Commit Graph

1660 Commits

Author SHA1 Message Date
Matt Fleming a55c7454a8 sched/topology: Improve load balancing on AMD EPYC systems
SD_BALANCE_{FORK,EXEC} and SD_WAKE_AFFINE are stripped in sd_init()
for any sched domains with a NUMA distance greater than 2 hops
(RECLAIM_DISTANCE). The idea being that it's expensive to balance
across domains that far apart.

However, as is rather unfortunately explained in:

  commit 32e45ff43e ("mm: increase RECLAIM_DISTANCE to 30")

the value for RECLAIM_DISTANCE is based on node distance tables from
2011-era hardware.

Current AMD EPYC machines have the following NUMA node distances:

 node distances:
 node   0   1   2   3   4   5   6   7
   0:  10  16  16  16  32  32  32  32
   1:  16  10  16  16  32  32  32  32
   2:  16  16  10  16  32  32  32  32
   3:  16  16  16  10  32  32  32  32
   4:  32  32  32  32  10  16  16  16
   5:  32  32  32  32  16  10  16  16
   6:  32  32  32  32  16  16  10  16
   7:  32  32  32  32  16  16  16  10

where 2 hops is 32.

The result is that the scheduler fails to load balance properly across
NUMA nodes on different sockets -- 2 hops apart.

For example, pinning 16 busy threads to NUMA nodes 0 (CPUs 0-7) and 4
(CPUs 32-39) like so,

  $ numactl -C 0-7,32-39 ./spinner 16

causes all threads to fork and remain on node 0 until the active
balancer kicks in after a few seconds and forcibly moves some threads
to node 4.

Override node_reclaim_distance for AMD Zen.

Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Suravee.Suthikulpanit@amd.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas.Lendacky@amd.com
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20190808195301.13222-3-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-03 09:17:37 +02:00
David Rientjes cd96103838 mm, page_alloc: move_freepages should not examine struct page of reserved memory
After commit 907ec5fca3 ("mm: zero remaining unavailable struct
pages"), struct page of reserved memory is zeroed.  This causes
page->flags to be 0 and fixes issues related to reading
/proc/kpageflags, for example, of reserved memory.

The VM_BUG_ON() in move_freepages_block(), however, assumes that
page_zone() is meaningful even for reserved memory.  That assumption is
no longer true after the aforementioned commit.

There's no reason why move_freepages_block() should be testing the
legitimacy of page_zone() for reserved memory; its scope is limited only
to pages on the zone's freelist.

Note that pfn_valid() can be true for reserved memory: there is a
backing struct page.  The check for page_to_nid(page) is also buggy but
reserved memory normally only appears on node 0 so the zeroing doesn't
affect this.

Move the debug checks to after verifying PageBuddy is true.  This
isolates the scope of the checks to only be for buddy pages which are on
the zone's freelist which move_freepages_block() is operating on.  In
this case, an incorrect node or zone is a bug worthy of being warned
about (and the examination of struct page is acceptable bcause this
memory is not reserved).

Why does move_freepages_block() gets called on reserved memory? It's
simply math after finding a valid free page from the per-zone free area
to use as fallback.  We find the beginning and end of the pageblock of
the valid page and that can bring us into memory that was reserved per
the e820.  pfn_valid() is still true (it's backed by a struct page), but
since it's zero'd we shouldn't make any inferences here about comparing
its node or zone.  The current node check just happens to succeed most
of the time by luck because reserved memory typically appears on node 0.

The fix here is to validate that we actually have buddy pages before
testing if there's any type of zone or node strangeness going on.

We noticed it almost immediately after bringing 907ec5fca3 in on
CONFIG_DEBUG_VM builds.  It depends on finding specific free pages in
the per-zone free area where the math in move_freepages() will bring the
start or end pfn into reserved memory and wanting to claim that entire
pageblock as a new migratetype.  So the path will be rare, require
CONFIG_DEBUG_VM, and require fallback to a different migratetype.

Some struct pages were already zeroed from reserve pages before
907ec5fca3c so it theoretically could trigger before this commit.  I
think it's rare enough under a config option that most people don't run
that others may not have noticed.  I wouldn't argue against a stable tag
and the backport should be easy enough, but probably wouldn't single out
a commit that this is fixing.

Mel said:

: The overhead of the debugging check is higher with this patch although
: it'll only affect debug builds and the path is not particularly hot.
: If this was a concern, I think it would be reasonable to simply remove
: the debugging check as the zone boundaries are checked in
: move_freepages_block and we never expect a zone/node to be smaller than
: a pageblock and stuck in the middle of another zone.

Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1908122036560.10779@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-24 19:48:42 -07:00
Christoph Hellwig fdc029b19d memremap: remove the dev field in struct dev_pagemap
The dev field in struct dev_pagemap is only used to print dev_name in two
places, which are at best nice to have.  Just remove the field and thus
the name in those two messages.

Link: https://lore.kernel.org/r/20190818090557.17853-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Bharata B Rao <bharata@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-08-20 09:41:35 -03:00
Dan Williams ba72b4c8cf mm/sparsemem: support sub-section hotplug
The libnvdimm sub-system has suffered a series of hacks and broken
workarounds for the memory-hotplug implementation's awkward
section-aligned (128MB) granularity.

For example the following backtrace is emitted when attempting
arch_add_memory() with physical address ranges that intersect 'System
RAM' (RAM) with 'Persistent Memory' (PMEM) within a given section:

    # cat /proc/iomem | grep -A1 -B1 Persistent\ Memory
    100000000-1ffffffff : System RAM
    200000000-303ffffff : Persistent Memory (legacy)
    304000000-43fffffff : System RAM
    440000000-23ffffffff : Persistent Memory
    2400000000-43bfffffff : Persistent Memory
      2400000000-43bfffffff : namespace2.0

    WARNING: CPU: 38 PID: 928 at arch/x86/mm/init_64.c:850 add_pages+0x5c/0x60
    [..]
    RIP: 0010:add_pages+0x5c/0x60
    [..]
    Call Trace:
     devm_memremap_pages+0x460/0x6e0
     pmem_attach_disk+0x29e/0x680 [nd_pmem]
     ? nd_dax_probe+0xfc/0x120 [libnvdimm]
     nvdimm_bus_probe+0x66/0x160 [libnvdimm]

It was discovered that the problem goes beyond RAM vs PMEM collisions as
some platform produce PMEM vs PMEM collisions within a given section.
The libnvdimm workaround for that case revealed that the libnvdimm
section-alignment-padding implementation has been broken for a long
while.

A fix for that long-standing breakage introduces as many problems as it
solves as it would require a backward-incompatible change to the
namespace metadata interpretation.  Instead of that dubious route [1],
address the root problem in the memory-hotplug implementation.

Note that EEXIST is no longer treated as success as that is how
sparse_add_section() reports subsection collisions, it was also obviated
by recent changes to perform the request_region() for 'System RAM'
before arch_add_memory() in the add_memory() sequence.

[1] https://lore.kernel.org/r/155000671719.348031.2347363160141119237.stgit@dwillia2-desk3.amr.corp.intel.com

[osalvador@suse.de: fix deactivate_section for early sections]
  Link: http://lkml.kernel.org/r/20190715081549.32577-2-osalvador@suse.de
Link: http://lkml.kernel.org/r/156092354368.979959.6232443923440952359.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>	[ppc64]
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18 17:08:07 -07:00
Dan Williams 46d945aeab mm: kill is_dev_zone() helper
Given there are no more usages of is_dev_zone() outside of 'ifdef
CONFIG_ZONE_DEVICE' protection, kill off the compilation helper.

Link: http://lkml.kernel.org/r/156092353211.979959.1489004866360828964.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Wei Yang <richardw.yang@linux.intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>	[ppc64]
Cc: Michal Hocko <mhocko@suse.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18 17:08:07 -07:00
Dan Williams f46edbd1b1 mm/sparsemem: add helpers track active portions of a section at boot
Prepare for hot{plug,remove} of sub-ranges of a section by tracking a
sub-section active bitmask, each bit representing a PMD_SIZE span of the
architecture's memory hotplug section size.

The implications of a partially populated section is that pfn_valid()
needs to go beyond a valid_section() check and either determine that the
section is an "early section", or read the sub-section active ranges
from the bitmask.  The expectation is that the bitmask (subsection_map)
fits in the same cacheline as the valid_section() / early_section()
data, so the incremental performance overhead to pfn_valid() should be
negligible.

The rationale for using early_section() to short-ciruit the
subsection_map check is that there are legacy code paths that use
pfn_valid() at section granularity before validating the pfn against
pgdat data.  So, the early_section() check allows those traditional
assumptions to persist while also permitting subsection_map to tell the
truth for purposes of populating the unused portions of early sections
with PMEM and other ZONE_DEVICE mappings.

Link: http://lkml.kernel.org/r/156092350874.979959.18185938451405518285.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Qian Cai <cai@lca.pw>
Tested-by: Jane Chu <jane.chu@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>	[ppc64]
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18 17:08:07 -07:00
Dan Williams f1eca35a0d mm/sparsemem: introduce struct mem_section_usage
Patch series "mm: Sub-section memory hotplug support", v10.

The memory hotplug section is an arbitrary / convenient unit for memory
hotplug.  'Section-size' units have bled into the user interface
('memblock' sysfs) and can not be changed without breaking existing
userspace.  The section-size constraint, while mostly benign for typical
memory hotplug, has and continues to wreak havoc with 'device-memory'
use cases, persistent memory (pmem) in particular.  Recall that pmem
uses devm_memremap_pages(), and subsequently arch_add_memory(), to
allocate a 'struct page' memmap for pmem.  However, it does not use the
'bottom half' of memory hotplug, i.e.  never marks pmem pages online and
never exposes the userspace memblock interface for pmem.  This leaves an
opening to redress the section-size constraint.

To date, the libnvdimm subsystem has attempted to inject padding to
satisfy the internal constraints of arch_add_memory().  Beyond
complicating the code, leading to bugs [2], wasting memory, and limiting
configuration flexibility, the padding hack is broken when the platform
changes this physical memory alignment of pmem from one boot to the
next.  Device failure (intermittent or permanent) and physical
reconfiguration are events that can cause the platform firmware to
change the physical placement of pmem on a subsequent boot, and device
failure is an everyday event in a data-center.

It turns out that sections are only a hard requirement of the
user-facing interface for memory hotplug and with a bit more
infrastructure sub-section arch_add_memory() support can be added for
kernel internal usages like devm_memremap_pages().  Here is an analysis
of the current design assumptions in the current code and how they are
addressed in the new implementation:

Current design assumptions:

 - Sections that describe boot memory (early sections) are never
   unplugged / removed.

 - pfn_valid(), in the CONFIG_SPARSEMEM_VMEMMAP=y, case devolves to a
   valid_section() check

 - __add_pages() and helper routines assume all operations occur in
   PAGES_PER_SECTION units.

 - The memblock sysfs interface only comprehends full sections

New design assumptions:

 - Sections are instrumented with a sub-section bitmask to track (on
   x86) individual 2MB sub-divisions of a 128MB section.

 - Partially populated early sections can be extended with additional
   sub-sections, and those sub-sections can be removed with
   arch_remove_memory(). With this in place we no longer lose usable
   memory capacity to padding.

 - pfn_valid() is updated to look deeper than valid_section() to also
   check the active-sub-section mask. This indication is in the same
   cacheline as the valid_section() so the performance impact is
   expected to be negligible. So far the lkp robot has not reported any
   regressions.

 - Outside of the core vmemmap population routines which are replaced,
   other helper routines like shrink_{zone,pgdat}_span() are updated to
   handle the smaller granularity. Core memory hotplug routines that
   deal with online memory are not touched.

 - The existing memblock sysfs user api guarantees / assumptions are not
   touched since this capability is limited to !online
   !memblock-sysfs-accessible sections.

Meanwhile the issue reports continue to roll in from users that do not
understand when and how the 128MB constraint will bite them.  The current
implementation relied on being able to support at least one misaligned
namespace, but that immediately falls over on any moderately complex
namespace creation attempt.  Beyond the initial problem of 'System RAM'
colliding with pmem, and the unsolvable problem of physical alignment
changes, Linux is now being exposed to platforms that collide pmem ranges
with other pmem ranges by default [3].  In short, devm_memremap_pages()
has pushed the venerable section-size constraint past the breaking point,
and the simplicity of section-aligned arch_add_memory() is no longer
tenable.

These patches are exposed to the kbuild robot on a subsection-v10 branch
[4], and a preview of the unit test for this functionality is available
on the 'subsection-pending' branch of ndctl [5].

[2]: https://lore.kernel.org/r/155000671719.348031.2347363160141119237.stgit@dwillia2-desk3.amr.corp.intel.com
[3]: https://github.com/pmem/ndctl/issues/76
[4]: https://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm.git/log/?h=subsection-v10
[5]: https://github.com/pmem/ndctl/commit/7c59b4867e1c

This patch (of 13):

Towards enabling memory hotplug to track partial population of a section,
introduce 'struct mem_section_usage'.

A pointer to a 'struct mem_section_usage' instance replaces the existing
pointer to a 'pageblock_flags' bitmap.  Effectively it adds one more
'unsigned long' beyond the 'pageblock_flags' (usemap) allocation to house
a new 'subsection_map' bitmap.  The new bitmap enables the memory
hot{plug,remove} implementation to act on incremental sub-divisions of a
section.

SUBSECTION_SHIFT is defined as global constant instead of per-architecture
value like SECTION_SIZE_BITS in order to allow cross-arch compatibility of
subsection users.  Specifically a common subsection size allows for the
possibility that persistent memory namespace configurations be made
compatible across architectures.

The primary motivation for this functionality is to support platforms that
mix "System RAM" and "Persistent Memory" within a single section, or
multiple PMEM ranges with different mapping lifetimes within a single
section.  The section restriction for hotplug has caused an ongoing saga
of hacks and bugs for devm_memremap_pages() users.

Beyond the fixups to teach existing paths how to retrieve the 'usemap'
from a section, and updates to usemap allocation path, there are no
expected behavior changes.

Link: http://lkml.kernel.org/r/156092349845.979959.73333291612799019.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Wei Yang <richardw.yang@linux.intel.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>	[ppc64]
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Qian Cai <cai@lca.pw>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18 17:08:07 -07:00
Yafang Shao e5ca8071fe mm/vmscan.c: add a new member reclaim_state in struct shrink_control
Patch series "mm/vmscan: calculate reclaimed slab in all reclaim paths".

This patchset is to fix the issues in doing shrink slab.

There're six different reclaim paths by now,
 - kswapd reclaim path
 - node reclaim path
 - hibernate preallocate memory reclaim path
 - direct reclaim path
 - memcg reclaim path
 - memcg softlimit reclaim path

The slab caches reclaimed in these paths are only calculated in the
above three paths.  The issues are detailed explained in patch #2.  We
should calculate the reclaimed slab caches in every reclaim path.  In
order to do it, the struct reclaim_state is placed into the struct
shrink_control.

In node reclaim path, there'is another issue about shrinking slab, which
is adressed in "mm/vmscan: shrink slab in node reclaim"
(https://lore.kernel.org/linux-mm/1559874946-22960-1-git-send-email-laoar.shao@gmail.com/).

This patch (of 2):

The struct reclaim_state is used to record how many slab caches are
reclaimed in one reclaim path.  The struct shrink_control is used to
control one reclaim path.  So we'd better put reclaim_state into
shrink_control.

[laoar.shao@gmail.com: remove reclaim_state assignment from __perform_reclaim()]
Link: http://lkml.kernel.org/r/1561381582-13697-1-git-send-email-laoar.shao@gmail.com
Link: http://lkml.kernel.org/r/1561112086-6169-2-git-send-email-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-16 19:23:21 -07:00
Linus Torvalds fec88ab0af HMM patches for 5.3
Improvements and bug fixes for the hmm interface in the kernel:
 
 - Improve clarity, locking and APIs related to the 'hmm mirror' feature
   merged last cycle. In linux-next we now see AMDGPU and nouveau to be
   using this API.
 
 - Remove old or transitional hmm APIs. These are hold overs from the past
   with no users, or APIs that existed only to manage cross tree conflicts.
   There are still a few more of these cleanups that didn't make the merge
   window cut off.
 
 - Improve some core mm APIs:
   * export alloc_pages_vma() for driver use
   * refactor into devm_request_free_mem_region() to manage
     DEVICE_PRIVATE resource reservations
   * refactor duplicative driver code into the core dev_pagemap
     struct
 
 - Remove hmm wrappers of improved core mm APIs, instead have drivers use
   the simplified API directly
 
 - Remove DEVICE_PUBLIC
 
 - Simplify the kconfig flow for the hmm users and core code
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Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma

Pull HMM updates from Jason Gunthorpe:
 "Improvements and bug fixes for the hmm interface in the kernel:

   - Improve clarity, locking and APIs related to the 'hmm mirror'
     feature merged last cycle. In linux-next we now see AMDGPU and
     nouveau to be using this API.

   - Remove old or transitional hmm APIs. These are hold overs from the
     past with no users, or APIs that existed only to manage cross tree
     conflicts. There are still a few more of these cleanups that didn't
     make the merge window cut off.

   - Improve some core mm APIs:
       - export alloc_pages_vma() for driver use
       - refactor into devm_request_free_mem_region() to manage
         DEVICE_PRIVATE resource reservations
       - refactor duplicative driver code into the core dev_pagemap
         struct

   - Remove hmm wrappers of improved core mm APIs, instead have drivers
     use the simplified API directly

   - Remove DEVICE_PUBLIC

   - Simplify the kconfig flow for the hmm users and core code"

* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (42 commits)
  mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR
  mm: remove the HMM config option
  mm: sort out the DEVICE_PRIVATE Kconfig mess
  mm: simplify ZONE_DEVICE page private data
  mm: remove hmm_devmem_add
  mm: remove hmm_vma_alloc_locked_page
  nouveau: use devm_memremap_pages directly
  nouveau: use alloc_page_vma directly
  PCI/P2PDMA: use the dev_pagemap internal refcount
  device-dax: use the dev_pagemap internal refcount
  memremap: provide an optional internal refcount in struct dev_pagemap
  memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag
  memremap: remove the data field in struct dev_pagemap
  memremap: add a migrate_to_ram method to struct dev_pagemap_ops
  memremap: lift the devmap_enable manipulation into devm_memremap_pages
  memremap: pass a struct dev_pagemap to ->kill and ->cleanup
  memremap: move dev_pagemap callbacks into a separate structure
  memremap: validate the pagemap type passed to devm_memremap_pages
  mm: factor out a devm_request_free_mem_region helper
  mm: export alloc_pages_vma
  ...
2019-07-14 19:42:11 -07:00
Alexander Potapenko 6471384af2 mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options
Patch series "add init_on_alloc/init_on_free boot options", v10.

Provide init_on_alloc and init_on_free boot options.

These are aimed at preventing possible information leaks and making the
control-flow bugs that depend on uninitialized values more deterministic.

Enabling either of the options guarantees that the memory returned by the
page allocator and SL[AU]B is initialized with zeroes.  SLOB allocator
isn't supported at the moment, as its emulation of kmem caches complicates
handling of SLAB_TYPESAFE_BY_RCU caches correctly.

Enabling init_on_free also guarantees that pages and heap objects are
initialized right after they're freed, so it won't be possible to access
stale data by using a dangling pointer.

As suggested by Michal Hocko, right now we don't let the heap users to
disable initialization for certain allocations.  There's not enough
evidence that doing so can speed up real-life cases, and introducing ways
to opt-out may result in things going out of control.

This patch (of 2):

The new options are needed to prevent possible information leaks and make
control-flow bugs that depend on uninitialized values more deterministic.

This is expected to be on-by-default on Android and Chrome OS.  And it
gives the opportunity for anyone else to use it under distros too via the
boot args.  (The init_on_free feature is regularly requested by folks
where memory forensics is included in their threat models.)

init_on_alloc=1 makes the kernel initialize newly allocated pages and heap
objects with zeroes.  Initialization is done at allocation time at the
places where checks for __GFP_ZERO are performed.

init_on_free=1 makes the kernel initialize freed pages and heap objects
with zeroes upon their deletion.  This helps to ensure sensitive data
doesn't leak via use-after-free accesses.

Both init_on_alloc=1 and init_on_free=1 guarantee that the allocator
returns zeroed memory.  The two exceptions are slab caches with
constructors and SLAB_TYPESAFE_BY_RCU flag.  Those are never
zero-initialized to preserve their semantics.

Both init_on_alloc and init_on_free default to zero, but those defaults
can be overridden with CONFIG_INIT_ON_ALLOC_DEFAULT_ON and
CONFIG_INIT_ON_FREE_DEFAULT_ON.

If either SLUB poisoning or page poisoning is enabled, those options take
precedence over init_on_alloc and init_on_free: initialization is only
applied to unpoisoned allocations.

Slowdown for the new features compared to init_on_free=0, init_on_alloc=0:

hackbench, init_on_free=1:  +7.62% sys time (st.err 0.74%)
hackbench, init_on_alloc=1: +7.75% sys time (st.err 2.14%)

Linux build with -j12, init_on_free=1:  +8.38% wall time (st.err 0.39%)
Linux build with -j12, init_on_free=1:  +24.42% sys time (st.err 0.52%)
Linux build with -j12, init_on_alloc=1: -0.13% wall time (st.err 0.42%)
Linux build with -j12, init_on_alloc=1: +0.57% sys time (st.err 0.40%)

The slowdown for init_on_free=0, init_on_alloc=0 compared to the baseline
is within the standard error.

The new features are also going to pave the way for hardware memory
tagging (e.g.  arm64's MTE), which will require both on_alloc and on_free
hooks to set the tags for heap objects.  With MTE, tagging will have the
same cost as memory initialization.

Although init_on_free is rather costly, there are paranoid use-cases where
in-memory data lifetime is desired to be minimized.  There are various
arguments for/against the realism of the associated threat models, but
given that we'll need the infrastructure for MTE anyway, and there are
people who want wipe-on-free behavior no matter what the performance cost,
it seems reasonable to include it in this series.

[glider@google.com: v8]
  Link: http://lkml.kernel.org/r/20190626121943.131390-2-glider@google.com
[glider@google.com: v9]
  Link: http://lkml.kernel.org/r/20190627130316.254309-2-glider@google.com
[glider@google.com: v10]
  Link: http://lkml.kernel.org/r/20190628093131.199499-2-glider@google.com
Link: http://lkml.kernel.org/r/20190617151050.92663-2-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.cz>		[page and dmapool parts
Acked-by: James Morris <jamorris@linux.microsoft.com>]
Cc: Christoph Lameter <cl@linux.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Sandeep Patil <sspatil@android.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Jann Horn <jannh@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12 11:05:46 -07:00
Nicholas Piggin e03a5125ec mm/large system hash: clear hashdist when only one node with memory is booted
CONFIG_NUMA on 64-bit CPUs currently enables hashdist unconditionally even
when booting on single node machines.  This causes the large system hashes
to be allocated with vmalloc, and mapped with small pages.

This change clears hashdist if only one node has come up with memory.

This results in the important large inode and dentry hashes using memblock
allocations.  All others are within 4MB size up to about 128GB of RAM,
which allows them to be allocated from the linear map on most non-NUMA
images.

Other big hashes like futex and TCP should eventually be moved over to the
same style of allocation as those vfs caches that use HASH_EARLY if
!hashdist, so they don't exceed MAX_ORDER on very large non-NUMA images.

This brings dTLB misses for linux kernel tree `git diff` from ~45,000 to
~8,000 on a Kaby Lake KVM guest with 8MB dentry hash and mitigations=off
(performance is in the noise, under 1% difference, page tables are likely
to be well cached for this workload).

Link: http://lkml.kernel.org/r/20190605144814.29319-2-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12 11:05:46 -07:00
Nicholas Piggin ec11408a16 mm/large system hash: use vmalloc for size > MAX_ORDER when !hashdist
The kernel currently clamps large system hashes to MAX_ORDER when hashdist
is not set, which is rather arbitrary.

vmalloc space is limited on 32-bit machines, but this shouldn't result in
much more used because of small physical memory limiting system hash
sizes.

Include "vmalloc" or "linear" in the kernel log message.

Link: http://lkml.kernel.org/r/20190605144814.29319-1-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12 11:05:46 -07:00
Vlastimil Babka 3972f6bb1c mm, debug_pagealloc: use a page type instead of page_ext flag
When debug_pagealloc is enabled, we currently allocate the page_ext
array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag.  Now that
we have the page_type field in struct page, we can use that instead, as
guard pages are neither PageSlab nor mapped to userspace.  This reduces
memory overhead when debug_pagealloc is enabled and there are no other
features requiring the page_ext array.

Link: http://lkml.kernel.org/r/20190603143451.27353-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12 11:05:43 -07:00
Vlastimil Babka 4462b32c92 mm, page_alloc: more extensive free page checking with debug_pagealloc
The page allocator checks struct pages for expected state (mapcount,
flags etc) as pages are being allocated (check_new_page()) and freed
(free_pages_check()) to provide some defense against errors in page
allocator users.

Prior commits 479f854a20 ("mm, page_alloc: defer debugging checks of
pages allocated from the PCP") and 4db7548ccb ("mm, page_alloc: defer
debugging checks of freed pages until a PCP drain") this has happened
for order-0 pages as they were allocated from or freed to the per-cpu
caches (pcplists).  Since those are fast paths, the checks are now
performed only when pages are moved between pcplists and global free
lists.  This however lowers the chances of catching errors soon enough.

In order to increase the chances of the checks to catch errors, the
kernel has to be rebuilt with CONFIG_DEBUG_VM, which also enables
multiple other internal debug checks (VM_BUG_ON() etc), which is
suboptimal when the goal is to catch errors in mm users, not in mm code
itself.

To catch some wrong users of the page allocator we have
CONFIG_DEBUG_PAGEALLOC, which is designed to have virtually no overhead
unless enabled at boot time.  Memory corruptions when writing to freed
pages have often the same underlying errors (use-after-free, double free)
as corrupting the corresponding struct pages, so this existing debugging
functionality is a good fit to extend by also perform struct page checks
at least as often as if CONFIG_DEBUG_VM was enabled.

Specifically, after this patch, when debug_pagealloc is enabled on boot,
and CONFIG_DEBUG_VM disabled, pages are checked when allocated from or
freed to the pcplists *in addition* to being moved between pcplists and
free lists.  When both debug_pagealloc and CONFIG_DEBUG_VM are enabled,
pages are checked when being moved between pcplists and free lists *in
addition* to when allocated from or freed to the pcplists.

When debug_pagealloc is not enabled on boot, the overhead in fast paths
should be virtually none thanks to the use of static key.

Link: http://lkml.kernel.org/r/20190603143451.27353-3-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12 11:05:43 -07:00
Vlastimil Babka 96a2b03f28 mm, debug_pagelloc: use static keys to enable debugging
Patch series "debug_pagealloc improvements".

I have been recently debugging some pcplist corruptions, where it would be
useful to perform struct page checks immediately as pages are allocated
from and freed to pcplists, which is now only possible by rebuilding the
kernel with CONFIG_DEBUG_VM (details in Patch 2 changelog).

To make this kind of debugging simpler in future on a distro kernel, I
have improved CONFIG_DEBUG_PAGEALLOC so that it has even smaller overhead
when not enabled at boot time (Patch 1) and also when enabled (Patch 3),
and extended it to perform the struct page checks more often when enabled
(Patch 2).  Now it can be configured in when building a distro kernel
without extra overhead, and debugging page use after free or double free
can be enabled simply by rebooting with debug_pagealloc=on.

This patch (of 3):

CONFIG_DEBUG_PAGEALLOC has been redesigned by 031bc5743f
("mm/debug-pagealloc: make debug-pagealloc boottime configurable") to
allow being always enabled in a distro kernel, but only perform its
expensive functionality when booted with debug_pagelloc=on.  We can
further reduce the overhead when not boot-enabled (including page
allocator fast paths) using static keys.  This patch introduces one for
debug_pagealloc core functionality, and another for the optional guard
page functionality (enabled by booting with debug_guardpage_minorder=X).

Link: http://lkml.kernel.org/r/20190603143451.27353-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12 11:05:43 -07:00
Denis Efremov 98ef2046f2 mm: remove the exporting of totalram_pages
Previously totalram_pages was the global variable.  Currently,
totalram_pages is the static inline function from the include/linux/mm.h
However, the function is also marked as EXPORT_SYMBOL, which is at best an
odd combination.  Because there is no point for the static inline function
from a public header to be exported, this commit removes the
EXPORT_SYMBOL() marking.  It will be still possible to use the function in
modules because all the symbols it depends on are exported.

Link: http://lkml.kernel.org/r/20190710141031.15642-1-efremov@linux.com
Fixes: ca79b0c211 ("mm: convert totalram_pages and totalhigh_pages variables to atomic")
Signed-off-by: Denis Efremov <efremov@linux.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12 11:05:43 -07:00
Juergen Gross b9705d8778 mm/page_alloc.c: fix regression with deferred struct page init
Commit 0e56acae4b ("mm: initialize MAX_ORDER_NR_PAGES at a time
instead of doing larger sections") is causing a regression on some
systems when the kernel is booted as Xen dom0.

The system will just hang in early boot.

Reason is an endless loop in get_page_from_freelist() in case the first
zone looked at has no free memory.  deferred_grow_zone() is always
returning true due to the following code snipplet:

  /* If the zone is empty somebody else may have cleared out the zone */
  if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
                                           first_deferred_pfn)) {
          pgdat->first_deferred_pfn = ULONG_MAX;
          pgdat_resize_unlock(pgdat, &flags);
          return true;
  }

This in turn results in the loop as get_page_from_freelist() is assuming
forward progress can be made by doing some more struct page
initialization.

Link: http://lkml.kernel.org/r/20190620160821.4210-1-jgross@suse.com
Fixes: 0e56acae4b ("mm: initialize MAX_ORDER_NR_PAGES at a time instead of doing larger sections")
Signed-off-by: Juergen Gross <jgross@suse.com>
Suggested-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Acked-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-05 11:12:07 +09:00
Christoph Hellwig 8a164fef9c mm: simplify ZONE_DEVICE page private data
Remove the clumsy hmm_devmem_page_{get,set}_drvdata helpers, and
instead just access the page directly.  Also make the page data
a void pointer, and thus much easier to use.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02 14:32:45 -03:00
Christoph Hellwig 514caf23a7 memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag
Add a flags field to struct dev_pagemap to replace the altmap_valid
boolean to be a little more extensible.  Also add a pgmap_altmap() helper
to find the optional altmap and clean up the code using the altmap using
it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02 14:32:44 -03:00
Thomas Gleixner 457c899653 treewide: Add SPDX license identifier for missed files
Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:45 +02:00
Dan Williams 97500a4a54 mm: maintain randomization of page free lists
When freeing a page with an order >= shuffle_page_order randomly select
the front or back of the list for insertion.

While the mm tries to defragment physical pages into huge pages this can
tend to make the page allocator more predictable over time.  Inject the
front-back randomness to preserve the initial randomness established by
shuffle_free_memory() when the kernel was booted.

The overhead of this manipulation is constrained by only being applied
for MAX_ORDER sized pages by default.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/154899812788.3165233.9066631950746578517.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Robert Elliott <elliott@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:48 -07:00
Dan Williams b03641af68 mm: move buddy list manipulations into helpers
In preparation for runtime randomization of the zone lists, take all
(well, most of) the list_*() functions in the buddy allocator and put
them in helper functions.  Provide a common control point for injecting
additional behavior when freeing pages.

[dan.j.williams@intel.com: fix buddy list helpers]
  Link: http://lkml.kernel.org/r/155033679702.1773410.13041474192173212653.stgit@dwillia2-desk3.amr.corp.intel.com
[vbabka@suse.cz: remove del_page_from_free_area() migratetype parameter]
  Link: http://lkml.kernel.org/r/4672701b-6775-6efd-0797-b6242591419e@suse.cz
Link: http://lkml.kernel.org/r/154899812264.3165233.5219320056406926223.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Robert Elliott <elliott@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:48 -07:00
Dan Williams e900a918b0 mm: shuffle initial free memory to improve memory-side-cache utilization
Patch series "mm: Randomize free memory", v10.

This patch (of 3):

Randomization of the page allocator improves the average utilization of
a direct-mapped memory-side-cache.  Memory side caching is a platform
capability that Linux has been previously exposed to in HPC
(high-performance computing) environments on specialty platforms.  In
that instance it was a smaller pool of high-bandwidth-memory relative to
higher-capacity / lower-bandwidth DRAM.  Now, this capability is going
to be found on general purpose server platforms where DRAM is a cache in
front of higher latency persistent memory [1].

Robert offered an explanation of the state of the art of Linux
interactions with memory-side-caches [2], and I copy it here:

    It's been a problem in the HPC space:
    http://www.nersc.gov/research-and-development/knl-cache-mode-performance-coe/

    A kernel module called zonesort is available to try to help:
    https://software.intel.com/en-us/articles/xeon-phi-software

    and this abandoned patch series proposed that for the kernel:
    https://lkml.kernel.org/r/20170823100205.17311-1-lukasz.daniluk@intel.com

    Dan's patch series doesn't attempt to ensure buffers won't conflict, but
    also reduces the chance that the buffers will. This will make performance
    more consistent, albeit slower than "optimal" (which is near impossible
    to attain in a general-purpose kernel).  That's better than forcing
    users to deploy remedies like:
        "To eliminate this gradual degradation, we have added a Stream
         measurement to the Node Health Check that follows each job;
         nodes are rebooted whenever their measured memory bandwidth
         falls below 300 GB/s."

A replacement for zonesort was merged upstream in commit cc9aec03e5
("x86/numa_emulation: Introduce uniform split capability").  With this
numa_emulation capability, memory can be split into cache sized
("near-memory" sized) numa nodes.  A bind operation to such a node, and
disabling workloads on other nodes, enables full cache performance.
However, once the workload exceeds the cache size then cache conflicts
are unavoidable.  While HPC environments might be able to tolerate
time-scheduling of cache sized workloads, for general purpose server
platforms, the oversubscribed cache case will be the common case.

The worst case scenario is that a server system owner benchmarks a
workload at boot with an un-contended cache only to see that performance
degrade over time, even below the average cache performance due to
excessive conflicts.  Randomization clips the peaks and fills in the
valleys of cache utilization to yield steady average performance.

Here are some performance impact details of the patches:

1/ An Intel internal synthetic memory bandwidth measurement tool, saw a
   3X speedup in a contrived case that tries to force cache conflicts.
   The contrived cased used the numa_emulation capability to force an
   instance of the benchmark to be run in two of the near-memory sized
   numa nodes.  If both instances were placed on the same emulated they
   would fit and cause zero conflicts.  While on separate emulated nodes
   without randomization they underutilized the cache and conflicted
   unnecessarily due to the in-order allocation per node.

2/ A well known Java server application benchmark was run with a heap
   size that exceeded cache size by 3X.  The cache conflict rate was 8%
   for the first run and degraded to 21% after page allocator aging.  With
   randomization enabled the rate levelled out at 11%.

3/ A MongoDB workload did not observe measurable difference in
   cache-conflict rates, but the overall throughput dropped by 7% with
   randomization in one case.

4/ Mel Gorman ran his suite of performance workloads with randomization
   enabled on platforms without a memory-side-cache and saw a mix of some
   improvements and some losses [3].

While there is potentially significant improvement for applications that
depend on low latency access across a wide working-set, the performance
may be negligible to negative for other workloads.  For this reason the
shuffle capability defaults to off unless a direct-mapped
memory-side-cache is detected.  Even then, the page_alloc.shuffle=0
parameter can be specified to disable the randomization on those systems.

Outside of memory-side-cache utilization concerns there is potentially
security benefit from randomization.  Some data exfiltration and
return-oriented-programming attacks rely on the ability to infer the
location of sensitive data objects.  The kernel page allocator, especially
early in system boot, has predictable first-in-first out behavior for
physical pages.  Pages are freed in physical address order when first
onlined.

Quoting Kees:
    "While we already have a base-address randomization
     (CONFIG_RANDOMIZE_MEMORY), attacks against the same hardware and
     memory layouts would certainly be using the predictability of
     allocation ordering (i.e. for attacks where the base address isn't
     important: only the relative positions between allocated memory).
     This is common in lots of heap-style attacks. They try to gain
     control over ordering by spraying allocations, etc.

     I'd really like to see this because it gives us something similar
     to CONFIG_SLAB_FREELIST_RANDOM but for the page allocator."

While SLAB_FREELIST_RANDOM reduces the predictability of some local slab
caches it leaves vast bulk of memory to be predictably in order allocated.
However, it should be noted, the concrete security benefits are hard to
quantify, and no known CVE is mitigated by this randomization.

Introduce shuffle_free_memory(), and its helper shuffle_zone(), to perform
a Fisher-Yates shuffle of the page allocator 'free_area' lists when they
are initially populated with free memory at boot and at hotplug time.  Do
this based on either the presence of a page_alloc.shuffle=Y command line
parameter, or autodetection of a memory-side-cache (to be added in a
follow-on patch).

The shuffling is done in terms of CONFIG_SHUFFLE_PAGE_ORDER sized free
pages where the default CONFIG_SHUFFLE_PAGE_ORDER is MAX_ORDER-1 i.e.  10,
4MB this trades off randomization granularity for time spent shuffling.
MAX_ORDER-1 was chosen to be minimally invasive to the page allocator
while still showing memory-side cache behavior improvements, and the
expectation that the security implications of finer granularity
randomization is mitigated by CONFIG_SLAB_FREELIST_RANDOM.  The
performance impact of the shuffling appears to be in the noise compared to
other memory initialization work.

This initial randomization can be undone over time so a follow-on patch is
introduced to inject entropy on page free decisions.  It is reasonable to
ask if the page free entropy is sufficient, but it is not enough due to
the in-order initial freeing of pages.  At the start of that process
putting page1 in front or behind page0 still keeps them close together,
page2 is still near page1 and has a high chance of being adjacent.  As
more pages are added ordering diversity improves, but there is still high
page locality for the low address pages and this leads to no significant
impact to the cache conflict rate.

[1]: https://itpeernetwork.intel.com/intel-optane-dc-persistent-memory-operating-modes/
[2]: https://lkml.kernel.org/r/AT5PR8401MB1169D656C8B5E121752FC0F8AB120@AT5PR8401MB1169.NAMPRD84.PROD.OUTLOOK.COM
[3]: https://lkml.org/lkml/2018/10/12/309

[dan.j.williams@intel.com: fix shuffle enable]
  Link: http://lkml.kernel.org/r/154943713038.3858443.4125180191382062871.stgit@dwillia2-desk3.amr.corp.intel.com
[cai@lca.pw: fix SHUFFLE_PAGE_ALLOCATOR help texts]
  Link: http://lkml.kernel.org/r/20190425201300.75650-1-cai@lca.pw
Link: http://lkml.kernel.org/r/154899811738.3165233.12325692939590944259.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Robert Elliott <elliott@hpe.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:48 -07:00
Baruch Siach 136ac591f0 mm: update references to page _refcount
Commit 0139aa7b7f ("mm: rename _count, field of the struct page, to
_refcount") left out a couple of references to the old field name.  Fix
that.

Link: http://lkml.kernel.org/r/cedf87b02eb8a6b3eac57e8e91da53fb15c3c44c.1556537475.git.baruch@tkos.co.il
Fixes: 0139aa7b7f ("mm: rename _count, field of the struct page, to _refcount")
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:47 -07:00
Mike Rapoport 350e88bad4 mm: memblock: make keeping memblock memory opt-in rather than opt-out
Most architectures do not need the memblock memory after the page
allocator is initialized, but only few enable ARCH_DISCARD_MEMBLOCK in the
arch Kconfig.

Replacing ARCH_DISCARD_MEMBLOCK with ARCH_KEEP_MEMBLOCK and inverting the
logic makes it clear which architectures actually use memblock after
system initialization and skips the necessity to add ARCH_DISCARD_MEMBLOCK
to the architectures that are still missing that option.

Link: http://lkml.kernel.org/r/1556102150-32517-1-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:50 -07:00
Yafang Shao 1c52e6d068 mm/page_alloc.c: remove unnecessary parameter in rmqueue_pcplist
Because rmqueue_pcplist() is only called when order is 0, we don't need to
use order as a parameter.

Link: http://lkml.kernel.org/r/1555591709-11744-1-git-send-email-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Pankaj Gupta <pagupta@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:50 -07:00
Michal Hocko 5557c766ab mm, memory_hotplug: cleanup memory offline path
check_pages_isolated_cb currently accounts the whole pfn range as being
offlined if test_pages_isolated suceeds on the range.  This is based on
the assumption that all pages in the range are freed which is currently
the case in most cases but it won't be with later changes, as pages marked
as vmemmap won't be isolated.

Move the offlined pages counting to offline_isolated_pages_cb and rely on
__offline_isolated_pages to return the correct value.
check_pages_isolated_cb will still do it's primary job and check the pfn
range.

While we are at it remove check_pages_isolated and offline_isolated_pages
and use directly walk_system_ram_range as do in online_pages.

Link: http://lkml.kernel.org/r/20190408082633.2864-2-osalvador@suse.de
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:49 -07:00
Alexander Duyck 0e56acae4b mm: initialize MAX_ORDER_NR_PAGES at a time instead of doing larger sections
Add yet another iterator, for_each_free_mem_range_in_zone_from, and then
use it to support initializing and freeing pages in groups no larger than
MAX_ORDER_NR_PAGES.  By doing this we can greatly improve the cache
locality of the pages while we do several loops over them in the init and
freeing process.

We are able to tighten the loops further as a result of the "from"
iterator as we can perform the initial checks for first_init_pfn in our
first call to the iterator, and continue without the need for those checks
via the "from" iterator.  I have added this functionality in the function
called deferred_init_mem_pfn_range_in_zone that primes the iterator and
causes us to exit if we encounter any failure.

On my x86_64 test system with 384GB of memory per node I saw a reduction
in initialization time from 1.85s to 1.38s as a result of this patch.

Link: http://lkml.kernel.org/r/20190405221231.12227.85836.stgit@localhost.localdomain
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <yi.z.zhang@linux.intel.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:49 -07:00
Alexander Duyck 837566e7e0 mm: implement new zone specific memblock iterator
Introduce a new iterator for_each_free_mem_pfn_range_in_zone.

This iterator will take care of making sure a given memory range provided
is in fact contained within a zone.  It takes are of all the bounds
checking we were doing in deferred_grow_zone, and deferred_init_memmap.
In addition it should help to speed up the search a bit by iterating until
the end of a range is greater than the start of the zone pfn range, and
will exit completely if the start is beyond the end of the zone.

Link: http://lkml.kernel.org/r/20190405221225.12227.22573.stgit@localhost.localdomain
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <yi.z.zhang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:49 -07:00
Alexander Duyck 56ec43d8b0 mm: drop meminit_pfn_in_nid as it is redundant
As best as I can tell the meminit_pfn_in_nid call is completely redundant.
The deferred memory initialization is already making use of
for_each_free_mem_range which in turn will call into __next_mem_range
which will only return a memory range if it matches the node ID provided
assuming it is not NUMA_NO_NODE.

I am operating on the assumption that there are no zones or pgdata_t
structures that have a NUMA node of NUMA_NO_NODE associated with them.  If
that is the case then __next_mem_range will never return a memory range
that doesn't match the zone's node ID and as such the check is redundant.

So one piece I would like to verify on this is if this works for ia64.
Technically it was using a different approach to get the node ID, but it
seems to have the node ID also encoded into the memblock.  So I am
assuming this is okay, but would like to get confirmation on that.

On my x86_64 test system with 384GB of memory per node I saw a reduction
in initialization time from 2.80s to 1.85s as a result of this patch.

Link: http://lkml.kernel.org/r/20190405221219.12227.93957.stgit@localhost.localdomain
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <yi.z.zhang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:49 -07:00
Linxu Fang 299c83dce9 mem-hotplug: fix node spanned pages when we have a node with only ZONE_MOVABLE
342332e6a9 ("mm/page_alloc.c: introduce kernelcore=mirror option") and
later patches rewrote the calculation of node spanned pages.

e506b99696 ("mem-hotplug: fix node spanned pages when we have a movable
node"), but the current code still has problems,

When we have a node with only zone_movable and the node id is not zero,
the size of node spanned pages is double added.

That's because we have an empty normal zone, and zone_start_pfn or
zone_end_pfn is not between arch_zone_lowest_possible_pfn and
arch_zone_highest_possible_pfn, so we need to use clamp to constrain the
range just like the commit <96e907d13602> (bootmem: Reimplement
__absent_pages_in_range() using for_each_mem_pfn_range()).

e.g.
Zone ranges:
  DMA      [mem 0x0000000000001000-0x0000000000ffffff]
  DMA32    [mem 0x0000000001000000-0x00000000ffffffff]
  Normal   [mem 0x0000000100000000-0x000000023fffffff]
Movable zone start for each node
  Node 0: 0x0000000100000000
  Node 1: 0x0000000140000000
Early memory node ranges
  node   0: [mem 0x0000000000001000-0x000000000009efff]
  node   0: [mem 0x0000000000100000-0x00000000bffdffff]
  node   0: [mem 0x0000000100000000-0x000000013fffffff]
  node   1: [mem 0x0000000140000000-0x000000023fffffff]

node 0 DMA	spanned:0xfff   present:0xf9e   absent:0x61
node 0 DMA32	spanned:0xff000 present:0xbefe0	absent:0x40020
node 0 Normal	spanned:0	present:0	absent:0
node 0 Movable	spanned:0x40000 present:0x40000 absent:0
On node 0 totalpages(node_present_pages): 1048446
node_spanned_pages:1310719
node 1 DMA	spanned:0	    present:0		absent:0
node 1 DMA32	spanned:0	    present:0		absent:0
node 1 Normal	spanned:0x100000    present:0x100000	absent:0
node 1 Movable	spanned:0x100000    present:0x100000	absent:0
On node 1 totalpages(node_present_pages): 2097152
node_spanned_pages:2097152
Memory: 6967796K/12582392K available (16388K kernel code, 3686K rwdata,
4468K rodata, 2160K init, 10444K bss, 5614596K reserved, 0K
cma-reserved)

It shows that the current memory of node 1 is double added.
After this patch, the problem is fixed.

node 0 DMA	spanned:0xfff   present:0xf9e   absent:0x61
node 0 DMA32	spanned:0xff000 present:0xbefe0	absent:0x40020
node 0 Normal	spanned:0	present:0	absent:0
node 0 Movable	spanned:0x40000 present:0x40000 absent:0
On node 0 totalpages(node_present_pages): 1048446
node_spanned_pages:1310719
node 1 DMA	spanned:0	    present:0		absent:0
node 1 DMA32	spanned:0	    present:0		absent:0
node 1 Normal	spanned:0	    present:0		absent:0
node 1 Movable	spanned:0x100000    present:0x100000	absent:0
On node 1 totalpages(node_present_pages): 1048576
node_spanned_pages:1048576
memory: 6967796K/8388088K available (16388K kernel code, 3686K rwdata,
4468K rodata, 2160K init, 10444K bss, 1420292K reserved, 0K
cma-reserved)

Link: http://lkml.kernel.org/r/1554178276-10372-1-git-send-email-fanglinxu@huawei.com
Signed-off-by: Linxu Fang <fanglinxu@huawei.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:48 -07:00
Alexandre Ghiti 4eb0716e86 hugetlb: allow to free gigantic pages regardless of the configuration
On systems without CONTIG_ALLOC activated but that support gigantic pages,
boottime reserved gigantic pages can not be freed at all.  This patch
simply enables the possibility to hand back those pages to memory
allocator.

Link: http://lkml.kernel.org/r/20190327063626.18421-5-alex@ghiti.fr
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Acked-by: David S. Miller <davem@davemloft.net> [sparc]
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:47 -07:00
Alexandre Ghiti 8df995f6bd mm: simplify MEMORY_ISOLATION && COMPACTION || CMA into CONTIG_ALLOC
This condition allows to define alloc_contig_range, so simplify it into a
more accurate naming.

Link: http://lkml.kernel.org/r/20190327063626.18421-4-alex@ghiti.fr
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:47 -07:00
Vlastimil Babka 63931eb975 mm, page_alloc: disallow __GFP_COMP in alloc_pages_exact()
alloc_pages_exact*() allocates a page of sufficient order and then splits
it to return only the number of pages requested.  That makes it
incompatible with __GFP_COMP, because compound pages cannot be split.

As shown by [1] things may silently work until the requested size
(possibly depending on user) stops being power of two.  Then for
CONFIG_DEBUG_VM, BUG_ON() triggers in split_page().  Without
CONFIG_DEBUG_VM, consequences are unclear.

There are several options here, none of them great:

1) Don't do the splitting when __GFP_COMP is passed, and return the
   whole compound page.  However if caller then returns it via
   free_pages_exact(), that will be unexpected and the freeing actions
   there will be wrong.

2) Warn and remove __GFP_COMP from the flags.  But the caller may have
   really wanted it, so things may break later somewhere.

3) Warn and return NULL.  However NULL may be unexpected, especially
   for small sizes.

This patch picks option 2, because as Michal Hocko put it: "callers wanted
it" is much less probable than "caller is simply confused and more gfp
flags is surely better than fewer".

[1] https://lore.kernel.org/lkml/20181126002805.GI18977@shao2-debian/T/#u

Link: http://lkml.kernel.org/r/0c6393eb-b28d-4607-c386-862a71f09de6@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:45 -07:00
Rick Edgecombe d633269286 mm/hibernation: Make hibernation handle unmapped pages
Make hibernate handle unmapped pages on the direct map when
CONFIG_ARCH_HAS_SET_ALIAS=y is set. These functions allow for setting pages
to invalid configurations, so now hibernate should check if the pages have
valid mappings and handle if they are unmapped when doing a hibernate
save operation.

Previously this checking was already done when CONFIG_DEBUG_PAGEALLOC=y
was configured. It does not appear to have a big hibernating performance
impact. The speed of the saving operation before this change was measured
as 819.02 MB/s, and after was measured at 813.32 MB/s.

Before:
[    4.670938] PM: Wrote 171996 kbytes in 0.21 seconds (819.02 MB/s)

After:
[    4.504714] PM: Wrote 178932 kbytes in 0.22 seconds (813.32 MB/s)

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-16-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-30 12:37:57 +02:00
Andrey Ryabinin 8118b82eb7 mm/page_alloc.c: fix never set ALLOC_NOFRAGMENT flag
Commit 0a79cdad5e ("mm: use alloc_flags to record if kswapd can wake")
removed setting of the ALLOC_NOFRAGMENT flag.  Bring it back.

The runtime effect is that ALLOC_NOFRAGMENT behaviour is restored so
that allocations are spread across local zones to avoid fragmentation
due to mixing pageblocks as long as possible.

Link: http://lkml.kernel.org/r/20190423120806.3503-2-aryabinin@virtuozzo.com
Fixes: 0a79cdad5e ("mm: use alloc_flags to record if kswapd can wake")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-26 09:18:05 -07:00
Andrey Ryabinin 8139ad043d mm/page_alloc.c: avoid potential NULL pointer dereference
ac.preferred_zoneref->zone passed to alloc_flags_nofragment() can be NULL.
'zone' pointer unconditionally derefernced in alloc_flags_nofragment().
Bail out on NULL zone to avoid potential crash.  Currently we don't see
any crashes only because alloc_flags_nofragment() has another bug which
allows compiler to optimize away all accesses to 'zone'.

Link: http://lkml.kernel.org/r/20190423120806.3503-1-aryabinin@virtuozzo.com
Fixes: 6bb154504f ("mm, page_alloc: spread allocations across zones before introducing fragmentation")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-26 09:18:05 -07:00
Mel Gorman ee8ab0eeb4 mm, page_alloc: always use a captured page regardless of compaction result
During the development of commit 5e1f0f098b ("mm, compaction: capture
a page under direct compaction"), a paranoid check was added to ensure
that if a captured page was available after compaction that it was
consistent with the final state of compaction.  The intent was to catch
serious programming bugs such as using a stale page pointer and causing
corruption problems.

However, it is possible to get a captured page even if compaction was
unsuccessful if an interrupt triggered and happened to free pages in
interrupt context that got merged into a suitable high-order page.  It's
highly unlikely but Li Wang did report the following warning on s390
occuring when testing OOM handling.  Note that the warning is slightly
edited for clarity.

  WARNING: CPU: 0 PID: 9783 at mm/page_alloc.c:3777 __alloc_pages_direct_compact+0x182/0x190
  Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs
    lockd grace fscache sunrpc pkey ghash_s390 prng xts aes_s390
    des_s390 des_generic sha512_s390 zcrypt_cex4 zcrypt vmur binfmt_misc
    ip_tables xfs libcrc32c dasd_fba_mod qeth_l2 dasd_eckd_mod dasd_mod
    qeth qdio lcs ctcm ccwgroup fsm dm_mirror dm_region_hash dm_log
    dm_mod
  CPU: 0 PID: 9783 Comm: copy.sh Kdump: loaded Not tainted 5.1.0-rc 5 #1

This patch simply removes the check entirely instead of trying to be
clever about pages freed from interrupt context.  If a serious
programming error was introduced, it is highly likely to be caught by
prep_new_page() instead.

Link: http://lkml.kernel.org/r/20190419085133.GH18914@techsingularity.net
Fixes: 5e1f0f098b ("mm, compaction: capture a page under direct compaction")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Li Wang <liwang@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-26 09:18:05 -07:00
Mel Gorman 24512228b7 mm: do not boost watermarks to avoid fragmentation for the DISCONTIG memory model
Mikulas Patocka reported that commit 1c30844d2d ("mm: reclaim small
amounts of memory when an external fragmentation event occurs") "broke"
memory management on parisc.

The machine is not NUMA but the DISCONTIG model creates three pgdats
even though it's a UMA machine for the following ranges

        0) Start 0x0000000000000000 End 0x000000003fffffff Size   1024 MB
        1) Start 0x0000000100000000 End 0x00000001bfdfffff Size   3070 MB
        2) Start 0x0000004040000000 End 0x00000040ffffffff Size   3072 MB

Mikulas reported:

	With the patch 1c30844d2, the kernel will incorrectly reclaim the
	first zone when it fills up, ignoring the fact that there are two
	completely free zones. Basiscally, it limits cache size to 1GiB.

	For example, if I run:
	# dd if=/dev/sda of=/dev/null bs=1M count=2048

	- with the proper kernel, there should be "Buffers - 2GiB"
	when this command finishes. With the patch 1c30844d2, buffers
	will consume just 1GiB or slightly more, because the kernel was
	incorrectly reclaiming them.

The page allocator and reclaim makes assumptions that pgdats really
represent NUMA nodes and zones represent ranges and makes decisions on
that basis.  Watermark boosting for small pgdats leads to unexpected
results even though this would have behaved reasonably on SPARSEMEM.

DISCONTIG is essentially deprecated and even parisc plans to move to
SPARSEMEM so there is no need to be fancy, this patch simply disables
watermark boosting by default on DISCONTIGMEM.

Link: http://lkml.kernel.org/r/20190419094335.GJ18914@techsingularity.net
Fixes: 1c30844d2d ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-26 09:18:05 -07:00
Qian Cai 1a9f219157 mm/hotplug: treat CMA pages as unmovable
has_unmovable_pages() is used by allocating CMA and gigantic pages as
well as the memory hotplug.  The later doesn't know how to offline CMA
pool properly now, but if an unused (free) CMA page is encountered, then
has_unmovable_pages() happily considers it as a free memory and
propagates this up the call chain.  Memory offlining code then frees the
page without a proper CMA tear down which leads to an accounting issues.
Moreover if the same memory range is onlined again then the memory never
gets back to the CMA pool.

State after memory offline:

 # grep cma /proc/vmstat
 nr_free_cma 205824

 # cat /sys/kernel/debug/cma/cma-kvm_cma/count
 209920

Also, kmemleak still think those memory address are reserved below but
have already been used by the buddy allocator after onlining.  This
patch fixes the situation by treating CMA pageblocks as unmovable except
when has_unmovable_pages() is called as part of CMA allocation.

  Offlined Pages 4096
  kmemleak: Cannot insert 0xc000201f7d040008 into the object search tree (overlaps existing)
  Call Trace:
    dump_stack+0xb0/0xf4 (unreliable)
    create_object+0x344/0x380
    __kmalloc_node+0x3ec/0x860
    kvmalloc_node+0x58/0x110
    seq_read+0x41c/0x620
    __vfs_read+0x3c/0x70
    vfs_read+0xbc/0x1a0
    ksys_read+0x7c/0x140
    system_call+0x5c/0x70
  kmemleak: Kernel memory leak detector disabled
  kmemleak: Object 0xc000201cc8000000 (size 13757317120):
  kmemleak:   comm "swapper/0", pid 0, jiffies 4294937297
  kmemleak:   min_count = -1
  kmemleak:   count = 0
  kmemleak:   flags = 0x5
  kmemleak:   checksum = 0
  kmemleak:   backtrace:
       cma_declare_contiguous+0x2a4/0x3b0
       kvm_cma_reserve+0x11c/0x134
       setup_arch+0x300/0x3f8
       start_kernel+0x9c/0x6e8
       start_here_common+0x1c/0x4b0
  kmemleak: Automatic memory scanning thread ended

[cai@lca.pw: use is_migrate_cma_page() and update commit log]
  Link: http://lkml.kernel.org/r/20190416170510.20048-1-cai@lca.pw
Link: http://lkml.kernel.org/r/20190413002623.8967-1-cai@lca.pw
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-04-19 09:46:05 -07:00
Qian Cai 9b7ea46a82 mm/hotplug: fix offline undo_isolate_page_range()
Commit f1dd2cd13c ("mm, memory_hotplug: do not associate hotadded
memory to zones until online") introduced move_pfn_range_to_zone() which
calls memmap_init_zone() during onlining a memory block.
memmap_init_zone() will reset pagetype flags and makes migrate type to
be MOVABLE.

However, in __offline_pages(), it also call undo_isolate_page_range()
after offline_isolated_pages() to do the same thing.  Due to commit
2ce13640b3 ("mm: __first_valid_page skip over offline pages") changed
__first_valid_page() to skip offline pages, undo_isolate_page_range()
here just waste CPU cycles looping around the offlining PFN range while
doing nothing, because __first_valid_page() will return NULL as
offline_isolated_pages() has already marked all memory sections within
the pfn range as offline via offline_mem_sections().

Also, after calling the "useless" undo_isolate_page_range() here, it
reaches the point of no returning by notifying MEM_OFFLINE.  Those pages
will be marked as MIGRATE_MOVABLE again once onlining.  The only thing
left to do is to decrease the number of isolated pageblocks zone counter
which would make some paths of the page allocation slower that the above
commit introduced.

Even if alloc_contig_range() can be used to isolate 16GB-hugetlb pages
on ppc64, an "int" should still be enough to represent the number of
pageblocks there.  Fix an incorrect comment along the way.

[cai@lca.pw: v4]
  Link: http://lkml.kernel.org/r/20190314150641.59358-1-cai@lca.pw
Link: http://lkml.kernel.org/r/20190313143133.46200-1-cai@lca.pw
Fixes: 2ce13640b3 ("mm: __first_valid_page skip over offline pages")
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>	[4.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-29 10:01:37 -07:00
Mike Rapoport 26fb3dae0a memblock: drop memblock_alloc_*_nopanic() variants
As all the memblock allocation functions return NULL in case of error
rather than panic(), the duplicates with _nopanic suffix can be removed.

Link: http://lkml.kernel.org/r/1548057848-15136-22-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>		[printk]
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Guo Ren <ren_guo@c-sky.com>				[c-sky]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Juergen Gross <jgross@suse.com>			[Xen]
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-12 10:04:02 -07:00
Christoph Hellwig afa0011289 mm: unexport free_reserved_area
This function is only used by built-in code, which makes perfect sense
given the purpose of it.

Link: http://lkml.kernel.org/r/20190213174621.29297-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:20 -08:00
Mike Rapoport a862f68a8b docs/core-api/mm: fix return value descriptions in mm/
Many kernel-doc comments in mm/ have the return value descriptions
either misformatted or omitted at all which makes kernel-doc script
unhappy:

$ make V=1 htmldocs
...
./mm/util.c:36: info: Scanning doc for kstrdup
./mm/util.c:41: warning: No description found for return value of 'kstrdup'
./mm/util.c:57: info: Scanning doc for kstrdup_const
./mm/util.c:66: warning: No description found for return value of 'kstrdup_const'
./mm/util.c:75: info: Scanning doc for kstrndup
./mm/util.c:83: warning: No description found for return value of 'kstrndup'
...

Fixing the formatting and adding the missing return value descriptions
eliminates ~100 such warnings.

Link: http://lkml.kernel.org/r/1549549644-4903-4-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:20 -08:00
Alexey Dobriyan ce0725f78a numa: make "nr_online_nodes" unsigned int
Number of online NUMA nodes can't be negative as well.  This doesn't
save space as the variable is used only in 32-bit context, but do it
anyway for consistency.

Link: http://lkml.kernel.org/r/20190201223151.GB15820@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:20 -08:00
Alexey Dobriyan b9726c26dc numa: make "nr_node_ids" unsigned int
Number of NUMA nodes can't be negative.

This saves a few bytes on x86_64:

	add/remove: 0/0 grow/shrink: 4/21 up/down: 27/-265 (-238)
	Function                                     old     new   delta
	hv_synic_alloc.cold                           88     110     +22
	prealloc_shrinker                            260     262      +2
	bootstrap                                    249     251      +2
	sched_init_numa                             1566    1567      +1
	show_slab_objects                            778     777      -1
	s_show                                      1201    1200      -1
	kmem_cache_init                              346     345      -1
	__alloc_workqueue_key                       1146    1145      -1
	mem_cgroup_css_alloc                        1614    1612      -2
	__do_sys_swapon                             4702    4699      -3
	__list_lru_init                              655     651      -4
	nic_probe                                   2379    2374      -5
	store_user_store                             118     111      -7
	red_zone_store                               106      99      -7
	poison_store                                 106      99      -7
	wq_numa_init                                 348     338     -10
	__kmem_cache_empty                            75      65     -10
	task_numa_free                               186     173     -13
	merge_across_nodes_store                     351     336     -15
	irq_create_affinity_masks                   1261    1246     -15
	do_numa_crng_init                            343     321     -22
	task_numa_fault                             4760    4737     -23
	swapfile_init                                179     156     -23
	hv_synic_alloc                               536     492     -44
	apply_wqattrs_prepare                        746     695     -51

Link: http://lkml.kernel.org/r/20190201223029.GA15820@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:19 -08:00
Mike Rapoport 23a7052a5d mm/page_alloc.c: check return value of memblock_alloc_node_nopanic()
There are two early memory allocations that use
memblock_alloc_node_nopanic() and do not check its return value.

While this happens very early during boot and chances that the
allocation will fail are diminishing, it is still worth to have proper
checks for the allocation errors.

Link: http://lkml.kernel.org/r/1547734941-944-1-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:18 -08:00
Wei Yang 8bb4e7a2ee mm: fix some typos in mm directory
No functional change.

Link: http://lkml.kernel.org/r/20190118235123.27843-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:18 -08:00
Greg Kroah-Hartman d9f7979c92 mm: no need to check return value of debugfs_create functions
When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Link: http://lkml.kernel.org/r/20190122152151.16139-14-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Laura Abbott <labbott@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:17 -08:00
Mel Gorman 5e1f0f098b mm, compaction: capture a page under direct compaction
Compaction is inherently race-prone as a suitable page freed during
compaction can be allocated by any parallel task.  This patch uses a
capture_control structure to isolate a page immediately when it is freed
by a direct compactor in the slow path of the page allocator.  The
intent is to avoid redundant scanning.

                                     5.0.0-rc1              5.0.0-rc1
                               selective-v3r17          capture-v3r19
Amean     fault-both-1         0.00 (   0.00%)        0.00 *   0.00%*
Amean     fault-both-3      2582.11 (   0.00%)     2563.68 (   0.71%)
Amean     fault-both-5      4500.26 (   0.00%)     4233.52 (   5.93%)
Amean     fault-both-7      5819.53 (   0.00%)     6333.65 (  -8.83%)
Amean     fault-both-12     9321.18 (   0.00%)     9759.38 (  -4.70%)
Amean     fault-both-18     9782.76 (   0.00%)    10338.76 (  -5.68%)
Amean     fault-both-24    15272.81 (   0.00%)    13379.55 *  12.40%*
Amean     fault-both-30    15121.34 (   0.00%)    16158.25 (  -6.86%)
Amean     fault-both-32    18466.67 (   0.00%)    18971.21 (  -2.73%)

Latency is only moderately affected but the devil is in the details.  A
closer examination indicates that base page fault latency is reduced but
latency of huge pages is increased as it takes creater care to succeed.
Part of the "problem" is that allocation success rates are close to 100%
even when under pressure and compaction gets harder

                                5.0.0-rc1              5.0.0-rc1
                          selective-v3r17          capture-v3r19
Percentage huge-3        96.70 (   0.00%)       98.23 (   1.58%)
Percentage huge-5        96.99 (   0.00%)       95.30 (  -1.75%)
Percentage huge-7        94.19 (   0.00%)       97.24 (   3.24%)
Percentage huge-12       94.95 (   0.00%)       97.35 (   2.53%)
Percentage huge-18       96.74 (   0.00%)       97.30 (   0.58%)
Percentage huge-24       97.07 (   0.00%)       97.55 (   0.50%)
Percentage huge-30       95.69 (   0.00%)       98.50 (   2.95%)
Percentage huge-32       96.70 (   0.00%)       99.27 (   2.65%)

And scan rates are reduced as expected by 6% for the migration scanner
and 29% for the free scanner indicating that there is less redundant
work.

Compaction migrate scanned    20815362    19573286
Compaction free scanned       16352612    11510663

[mgorman@techsingularity.net: remove redundant check]
  Link: http://lkml.kernel.org/r/20190201143853.GH9565@techsingularity.net
Link: http://lkml.kernel.org/r/20190118175136.31341-23-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:17 -08:00
Mel Gorman fd1444b272 mm, compaction: ignore the fragmentation avoidance boost for isolation and compaction
When pageblocks get fragmented, watermarks are artifically boosted to
reclaim pages to avoid further fragmentation events.  However,
compaction is often either fragmentation-neutral or moving movable pages
away from unmovable/reclaimable pages.  As the true watermarks are
preserved, allow compaction to ignore the boost factor.

The expected impact is very slight as the main benefit is that
compaction is slightly more likely to succeed when the system has been
fragmented very recently.  On both 1-socket and 2-socket machines for
THP-intensive allocation during fragmentation the success rate was
increased by less than 1% which is marginal.  However, detailed tracing
indicated that failure of migration due to a premature ENOMEM triggered
by watermark checks were eliminated.

Link: http://lkml.kernel.org/r/20190118175136.31341-9-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:16 -08:00
Wei Yang c52e75935f mm: remove extra drain pages on pcp list
In the current implementation, there are two places to isolate a range
of page: __offline_pages() and alloc_contig_range().  During this
procedure, it will drain pages on pcp list.

Below is a brief call flow:

  __offline_pages()/alloc_contig_range()
      start_isolate_page_range()
          set_migratetype_isolate()
              drain_all_pages()
      drain_all_pages()                 <--- A

This snippet shows the current logic is isolate and drain pcp list for
each pageblock and drain pcp list again for the whole range.

start_isolate_page_range is responsible for isolating the given pfn
range.  One part of that job is to make sure that also pages that are on
the allocator pcp lists are properly isolated.  Otherwise they could be
reused and the range wouldn't be completely isolated until the memory is
freed back.  While there is no strict guarantee here because pages might
get allocated at any time before drain_all_pages is called there doesn't
seem to be any strong demand for such a guarantee.

In any case, draining is already done at the isolation level and there
is no need to do it again later by start_isolate_page_range callers
(memory hotplug and CMA allocator currently).  Therefore remove
pointless draining in existing callers to make the code more clear and
functionally correct.

[mhocko@suse.com: provide a clearer changelog for the last two paragraphs]
Link: http://lkml.kernel.org/r/20190105233141.2329-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:15 -08:00
Shakeel Butt 60cd4bcd62 memcg: localize memcg_kmem_enabled() check
Move the memcg_kmem_enabled() checks into memcg kmem charge/uncharge
functions, so, the users don't have to explicitly check that condition.

This is purely code cleanup patch without any functional change.  Only
the order of checks in memcg_charge_slab() can potentially be changed
but the functionally it will be same.  This should not matter as
memcg_charge_slab() is not in the hot path.

Link: http://lkml.kernel.org/r/20190103161203.162375-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:15 -08:00
Anshuman Khandual 98fa15f34c mm: replace all open encodings for NUMA_NO_NODE
Patch series "Replace all open encodings for NUMA_NO_NODE", v3.

All these places for replacement were found by running the following
grep patterns on the entire kernel code.  Please let me know if this
might have missed some instances.  This might also have replaced some
false positives.  I will appreciate suggestions, inputs and review.

1. git grep "nid == -1"
2. git grep "node == -1"
3. git grep "nid = -1"
4. git grep "node = -1"

This patch (of 2):

At present there are multiple places where invalid node number is
encoded as -1.  Even though implicitly understood it is always better to
have macros in there.  Replace these open encodings for an invalid node
number with the global macro NUMA_NO_NODE.  This helps remove NUMA
related assumptions like 'invalid node' from various places redirecting
them to a common definition.

Link: http://lkml.kernel.org/r/1545127933-10711-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>	[ixgbe]
Acked-by: Jens Axboe <axboe@kernel.dk>			[mtip32xx]
Acked-by: Vinod Koul <vkoul@kernel.org>			[dmaengine.c]
Acked-by: Michael Ellerman <mpe@ellerman.id.au>		[powerpc]
Acked-by: Doug Ledford <dledford@redhat.com>		[drivers/infiniband]
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:14 -08:00
Arun KS a9cd410a3d mm/page_alloc.c: memory hotplug: free pages as higher order
When freeing pages are done with higher order, time spent on coalescing
pages by buddy allocator can be reduced.  With section size of 256MB,
hot add latency of a single section shows improvement from 50-60 ms to
less than 1 ms, hence improving the hot add latency by 60 times.  Modify
external providers of online callback to align with the change.

[arunks@codeaurora.org: v11]
  Link: http://lkml.kernel.org/r/1547792588-18032-1-git-send-email-arunks@codeaurora.org
[akpm@linux-foundation.org: remove unused local, per Arun]
[akpm@linux-foundation.org: avoid return of void-returning __free_pages_core(), per Oscar]
[akpm@linux-foundation.org: fix it for mm-convert-totalram_pages-and-totalhigh_pages-variables-to-atomic.patch]
[arunks@codeaurora.org: v8]
  Link: http://lkml.kernel.org/r/1547032395-24582-1-git-send-email-arunks@codeaurora.org
[arunks@codeaurora.org: v9]
  Link: http://lkml.kernel.org/r/1547098543-26452-1-git-send-email-arunks@codeaurora.org
Link: http://lkml.kernel.org/r/1538727006-5727-1-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS <arunks@codeaurora.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Srivatsa Vaddagiri <vatsa@codeaurora.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:14 -08:00
Qian Cai 4117992df6 page_poison: play nicely with KASAN
KASAN does not play well with the page poisoning (CONFIG_PAGE_POISONING).
It triggers false positives in the allocation path:

  BUG: KASAN: use-after-free in memchr_inv+0x2ea/0x330
  Read of size 8 at addr ffff88881f800000 by task swapper/0
  CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc1+ #54
  Call Trace:
   dump_stack+0xe0/0x19a
   print_address_description.cold.2+0x9/0x28b
   kasan_report.cold.3+0x7a/0xb5
   __asan_report_load8_noabort+0x19/0x20
   memchr_inv+0x2ea/0x330
   kernel_poison_pages+0x103/0x3d5
   get_page_from_freelist+0x15e7/0x4d90

because KASAN has not yet unpoisoned the shadow page for allocation
before it checks memchr_inv() but only found a stale poison pattern.

Also, false positives in free path,

  BUG: KASAN: slab-out-of-bounds in kernel_poison_pages+0x29e/0x3d5
  Write of size 4096 at addr ffff8888112cc000 by task swapper/0/1
  CPU: 5 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc1+ #55
  Call Trace:
   dump_stack+0xe0/0x19a
   print_address_description.cold.2+0x9/0x28b
   kasan_report.cold.3+0x7a/0xb5
   check_memory_region+0x22d/0x250
   memset+0x28/0x40
   kernel_poison_pages+0x29e/0x3d5
   __free_pages_ok+0x75f/0x13e0

due to KASAN adds poisoned redzones around slab objects, but the page
poisoning needs to poison the whole page.

Link: http://lkml.kernel.org/r/20190114233405.67843-1-cai@lca.pw
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 21:07:13 -08:00
Mel Gorman 94b3334cbe mm, page_alloc: fix a division by zero error when boosting watermarks v2
Yury Norov reported that an arm64 KVM instance could not boot since
after v5.0-rc1 and could addressed by reverting the patches

  1c30844d2d ("mm: reclaim small amounts of memory when an external
  73444bc4d8 ("mm, page_alloc: do not wake kswapd with zone lock held")

The problem is that a division by zero error is possible if boosting
occurs very early in boot if the system has very little memory.  This
patch avoids the division by zero error.

Link: http://lkml.kernel.org/r/20190213143012.GT9565@techsingularity.net
Fixes: 1c30844d2d ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-02-21 09:01:00 -08:00
Alexander Duyck 8644772637 mm: Use fixed constant in page_frag_alloc instead of size + 1
This patch replaces the size + 1 value introduced with the recent fix for 1
byte allocs with a constant value.

The idea here is to reduce code overhead as the previous logic would have
to read size into a register, then increment it, and write it back to
whatever field was being used. By using a constant we can avoid those
memory reads and arithmetic operations in favor of just encoding the
maximum value into the operation itself.

Fixes: 2c2ade8174 ("mm: page_alloc: fix ref bias in page_frag_alloc() for 1-byte allocs")
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-17 15:48:43 -08:00
Jann Horn 2c2ade8174 mm: page_alloc: fix ref bias in page_frag_alloc() for 1-byte allocs
The basic idea behind ->pagecnt_bias is: If we pre-allocate the maximum
number of references that we might need to create in the fastpath later,
the bump-allocation fastpath only has to modify the non-atomic bias value
that tracks the number of extra references we hold instead of the atomic
refcount. The maximum number of allocations we can serve (under the
assumption that no allocation is made with size 0) is nc->size, so that's
the bias used.

However, even when all memory in the allocation has been given away, a
reference to the page is still held; and in the `offset < 0` slowpath, the
page may be reused if everyone else has dropped their references.
This means that the necessary number of references is actually
`nc->size+1`.

Luckily, from a quick grep, it looks like the only path that can call
page_frag_alloc(fragsz=1) is TAP with the IFF_NAPI_FRAGS flag, which
requires CAP_NET_ADMIN in the init namespace and is only intended to be
used for kernel testing and fuzzing.

To test for this issue, put a `WARN_ON(page_ref_count(page) == 0)` in the
`offset < 0` path, below the virt_to_page() call, and then repeatedly call
writev() on a TAP device with IFF_TAP|IFF_NO_PI|IFF_NAPI_FRAGS|IFF_NAPI,
with a vector consisting of 15 elements containing 1 byte each.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-14 12:12:17 -05:00
Michal Hocko 4aa9fc2a43 Revert "mm, memory_hotplug: initialize struct pages for the full memory section"
This reverts commit 2830bf6f05.

The underlying assumption that one sparse section belongs into a single
numa node doesn't hold really. Robert Shteynfeld has reported a boot
failure. The boot log was not captured but his memory layout is as
follows:

  Early memory node ranges
    node   1: [mem 0x0000000000001000-0x0000000000090fff]
    node   1: [mem 0x0000000000100000-0x00000000dbdf8fff]
    node   1: [mem 0x0000000100000000-0x0000001423ffffff]
    node   0: [mem 0x0000001424000000-0x0000002023ffffff]

This means that node0 starts in the middle of a memory section which is
also in node1.  memmap_init_zone tries to initialize padding of a
section even when it is outside of the given pfn range because there are
code paths (e.g.  memory hotplug) which assume that the full worth of
memory section is always initialized.

In this particular case, though, such a range is already intialized and
most likely already managed by the page allocator.  Scribbling over
those pages corrupts the internal state and likely blows up when any of
those pages gets used.

Reported-by: Robert Shteynfeld <robert.shteynfeld@gmail.com>
Fixes: 2830bf6f05 ("mm, memory_hotplug: initialize struct pages for the full memory section")
Cc: stable@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-28 10:35:22 -08:00
Mel Gorman 73444bc4d8 mm, page_alloc: do not wake kswapd with zone lock held
syzbot reported the following regression in the latest merge window and
it was confirmed by Qian Cai that a similar bug was visible from a
different context.

  ======================================================
  WARNING: possible circular locking dependency detected
  4.20.0+ #297 Not tainted
  ------------------------------------------------------
  syz-executor0/8529 is trying to acquire lock:
  000000005e7fb829 (&pgdat->kswapd_wait){....}, at:
  __wake_up_common_lock+0x19e/0x330 kernel/sched/wait.c:120

  but task is already holding lock:
  000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: spin_lock
  include/linux/spinlock.h:329 [inline]
  000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue_bulk
  mm/page_alloc.c:2548 [inline]
  000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: __rmqueue_pcplist
  mm/page_alloc.c:3021 [inline]
  000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue_pcplist
  mm/page_alloc.c:3050 [inline]
  000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at: rmqueue
  mm/page_alloc.c:3072 [inline]
  000000009bb7bae0 (&(&zone->lock)->rlock){-.-.}, at:
  get_page_from_freelist+0x1bae/0x52a0 mm/page_alloc.c:3491

It appears to be a false positive in that the only way the lock ordering
should be inverted is if kswapd is waking itself and the wakeup
allocates debugging objects which should already be allocated if it's
kswapd doing the waking.  Nevertheless, the possibility exists and so
it's best to avoid the problem.

This patch flags a zone as needing a kswapd using the, surprisingly,
unused zone flag field.  The flag is read without the lock held to do
the wakeup.  It's possible that the flag setting context is not the same
as the flag clearing context or for small races to occur.  However, each
race possibility is harmless and there is no visible degredation in
fragmentation treatment.

While zone->flag could have continued to be unused, there is potential
for moving some existing fields into the flags field instead.
Particularly read-mostly ones like zone->initialized and
zone->contiguous.

Link: http://lkml.kernel.org/r/20190103225712.GJ31517@techsingularity.net
Fixes: 1c30844d2d ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
Reported-by: syzbot+93d94a001cfbce9e60e1@syzkaller.appspotmail.com
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-08 17:15:11 -08:00
Benjamin Poirier af3b854492 mm/page_alloc.c: allow error injection
Model call chain after should_failslab().  Likewise, we can now use a
kprobe to override the return value of should_fail_alloc_page() and inject
allocation failures into alloc_page*().

This will allow injecting allocation failures using the BCC tools even
without building kernel with CONFIG_FAIL_PAGE_ALLOC and booting it with a
fail_page_alloc= parameter, which incurs some overhead even when failures
are not being injected.  On the other hand, this patch adds an
unconditional call to should_fail_alloc_page() from page allocation
hotpath.  That overhead should be rather negligible with
CONFIG_FAIL_PAGE_ALLOC=n when there's no kprobe attached, though.

[vbabka@suse.cz: changelog addition]
Link: http://lkml.kernel.org/r/20181214074330.18917-1-bpoirier@suse.com
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:51 -08:00
Wei Yang d9367bd06f mm, page_alloc: enable pcpu_drain with zone capability
drain_all_pages is documented to drain per-cpu pages for a given zone (if
non-NULL).  The current implementation doesn't match the description
though.  It will drain all pcp pages for all zones that happen to have
cached pages on the same cpu as the given zone.  This will lead to
premature pcp cache draining for zones that are not of any interest to the
caller - e.g.  compaction, hwpoison or memory offline.

This forces the page allocator to take locks and potential lock contention
as a result.

There is no real reason for this sub-optimal implementation.  Replace
per-cpu work item with a dedicated structure which contains a pointer to
the zone and pass it over to the worker.  This will get the zone
information all the way down to the worker function and do the right job.

[akpm@linux-foundation.org: avoid 80-col tricks]
[mhocko@suse.com: refactor the whole changelog]
Link: http://lkml.kernel.org/r/20181212142550.61686-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:51 -08:00
Waiman Long 3c0c12cc8f mm/page_alloc.c: don't call kasan_free_pages() at deferred mem init
When CONFIG_KASAN is enabled on large memory SMP systems, the deferrred
pages initialization can take a long time.  Below were the reported init
times on a 8-socket 96-core 4TB IvyBridge system.

  1) Non-debug kernel without CONFIG_KASAN
     [    8.764222] node 1 initialised, 132086516 pages in 7027ms

  2) Debug kernel with CONFIG_KASAN
     [  146.288115] node 1 initialised, 132075466 pages in 143052ms

So the page init time in a debug kernel was 20X of the non-debug kernel.
The long init time can be problematic as the page initialization is done
with interrupt disabled.  In this particular case, it caused the
appearance of following warning messages as well as NMI backtraces of all
the cores that were doing the initialization.

[   68.240049] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[   68.241000] rcu: 	25-...0: (100 ticks this GP) idle=b72/1/0x4000000000000000 softirq=915/915 fqs=16252
[   68.241000] rcu: 	44-...0: (95 ticks this GP) idle=49a/1/0x4000000000000000 softirq=788/788 fqs=16253
[   68.241000] rcu: 	54-...0: (104 ticks this GP) idle=03a/1/0x4000000000000000 softirq=721/825 fqs=16253
[   68.241000] rcu: 	60-...0: (103 ticks this GP) idle=cbe/1/0x4000000000000000 softirq=637/740 fqs=16253
[   68.241000] rcu: 	72-...0: (105 ticks this GP) idle=786/1/0x4000000000000000 softirq=536/641 fqs=16253
[   68.241000] rcu: 	84-...0: (99 ticks this GP) idle=292/1/0x4000000000000000 softirq=537/537 fqs=16253
[   68.241000] rcu: 	111-...0: (104 ticks this GP) idle=bde/1/0x4000000000000000 softirq=474/476 fqs=16253
[   68.241000] rcu: 	(detected by 13, t=65018 jiffies, g=249, q=2)

The long init time was mainly caused by the call to kasan_free_pages() to
poison the newly initialized pages.  On a 4TB system, we are talking about
almost 500GB of memory probably on the same node.

In reality, we may not need to poison the newly initialized pages before
they are ever allocated.  So KASAN poisoning of freed pages before the
completion of deferred memory initialization is now disabled.  Those pages
will be properly poisoned when they are allocated or freed after deferred
pages initialization is done.

With this change, the new page initialization time became:

[   21.948010] node 1 initialised, 132075466 pages in 18702ms

This was still about double the non-debug kernel time, but was much
better than before.

Link: http://lkml.kernel.org/r/1544459388-8736-1-git-send-email-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:51 -08:00
Pingfan Liu 125b860b25 mm/pageblock: throw compile error if pageblock_bits cannot hold MIGRATE_TYPES
Currently, NR_PAGEBLOCK_BITS and MIGRATE_TYPES are not associated by code.
If someone adds extra migrate type, then he may forget to enlarge the
NR_PAGEBLOCK_BITS.  Hence it requires some way to fix.

NR_PAGEBLOCK_BITS depends on MIGRATE_TYPES, while these macro spread on
two different .h file with reverse dependency, it is a little hard to
refer to MIGRATE_TYPES in pageblock-flag.h.  This patch tries to remind
such relation in compiling-time.

Link: http://lkml.kernel.org/r/1544508709-11358-1-git-send-email-kernelfans@gmail.com
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:51 -08:00
Oscar Salvador bbe5d9939e mm/page_alloc.c: drop uneeded __meminit and __meminitdata
Since commit 03e85f9d5f ("mm/page_alloc: Introduce
free_area_init_core_hotplug"), some functions changed to only be called
during system initialization.  Concretly, free_area_init_node() and the
functions that hang from it.

Also, some variables are no longer used after the system has gone
through initialization.  So this could be considered as a late clean-up
for that patch.

This patch changes the functions from __meminit to __init, and the
variables from __meminitdata to __initdata.

In return, we get some KBs back:

Before:
  Freeing unused kernel image memory: 2472K

After:
  Freeing unused kernel image memory: 2480K

Link: http://lkml.kernel.org/r/20181204111507.4808-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:49 -08:00
Wei Yang 23b68cfaae mm: check nr_initialised with PAGES_PER_SECTION directly in defer_init()
When DEFERRED_STRUCT_PAGE_INIT is configured, only the first section of
each node's highest zone is initialized before defer stage.

static_init_pgcnt is used to store the number of pages like this:

    pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION,
                                              pgdat->node_spanned_pages);

because we don't want to overflow zone's range.

But this is not necessary, since defer_init() is called like this:

  memmap_init_zone()
    for pfn in [start_pfn, end_pfn)
      defer_init(pfn, end_pfn)

In case (pgdat->node_spanned_pages < PAGES_PER_SECTION), the loop would
stop before calling defer_init().

BTW, comparing PAGES_PER_SECTION with node_spanned_pages is not correct,
since nr_initialised is zone based instead of node based.  Even
node_spanned_pages is bigger than PAGES_PER_SECTION, its highest zone
would have pages less than PAGES_PER_SECTION.

Link: http://lkml.kernel.org/r/20181122094807.6985-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:49 -08:00
yuzhoujian ef8444ea01 mm, oom: reorganize the oom report in dump_header
OOM report contains several sections.  The first one is the allocation
context that has triggered the OOM.  Then we have cpuset context followed
by the stack trace of the OOM path.  The tird one is the OOM memory
information.  Followed by the current memory state of all system tasks.
At last, we will show oom eligible tasks and the information about the
chosen oom victim.

One thing that makes parsing more awkward than necessary is that we do not
have a single and easily parsable line about the oom context.  This patch
is reorganizing the oom report to

1) who invoked oom and what was the allocation request

[  515.902945] tuned invoked oom-killer: gfp_mask=0x6200ca(GFP_HIGHUSER_MOVABLE), order=0, oom_score_adj=0

2) OOM stack trace

[  515.904273] CPU: 24 PID: 1809 Comm: tuned Not tainted 4.20.0-rc3+ #3
[  515.905518] Hardware name: Inspur SA5212M4/YZMB-00370-107, BIOS 4.1.10 11/14/2016
[  515.906821] Call Trace:
[  515.908062]  dump_stack+0x5a/0x73
[  515.909311]  dump_header+0x55/0x28c
[  515.914260]  oom_kill_process+0x2d8/0x300
[  515.916708]  out_of_memory+0x145/0x4a0
[  515.917932]  __alloc_pages_slowpath+0x7d2/0xa16
[  515.919157]  __alloc_pages_nodemask+0x277/0x290
[  515.920367]  filemap_fault+0x3d0/0x6c0
[  515.921529]  ? filemap_map_pages+0x2b8/0x420
[  515.922709]  ext4_filemap_fault+0x2c/0x40 [ext4]
[  515.923884]  __do_fault+0x20/0x80
[  515.925032]  __handle_mm_fault+0xbc0/0xe80
[  515.926195]  handle_mm_fault+0xfa/0x210
[  515.927357]  __do_page_fault+0x233/0x4c0
[  515.928506]  do_page_fault+0x32/0x140
[  515.929646]  ? page_fault+0x8/0x30
[  515.930770]  page_fault+0x1e/0x30

3) OOM memory information

[  515.958093] Mem-Info:
[  515.959647] active_anon:26501758 inactive_anon:1179809 isolated_anon:0
 active_file:4402672 inactive_file:483963 isolated_file:1344
 unevictable:0 dirty:4886753 writeback:0 unstable:0
 slab_reclaimable:148442 slab_unreclaimable:18741
 mapped:1347 shmem:1347 pagetables:58669 bounce:0
 free:88663 free_pcp:0 free_cma:0
...

4) current memory state of all system tasks

[  516.079544] [    744]     0   744     9211     1345   114688       82             0 systemd-journal
[  516.082034] [    787]     0   787    31764        0   143360       92             0 lvmetad
[  516.084465] [    792]     0   792    10930        1   110592      208         -1000 systemd-udevd
[  516.086865] [   1199]     0  1199    13866        0   131072      112         -1000 auditd
[  516.089190] [   1222]     0  1222    31990        1   110592      157             0 smartd
[  516.091477] [   1225]     0  1225     4864       85    81920       43             0 irqbalance
[  516.093712] [   1226]     0  1226    52612        0   258048      426             0 abrtd
[  516.112128] [   1280]     0  1280   109774       55   299008      400             0 NetworkManager
[  516.113998] [   1295]     0  1295    28817       37    69632       24             0 ksmtuned
[  516.144596] [  10718]     0 10718  2622484  1721372 15998976   267219             0 panic
[  516.145792] [  10719]     0 10719  2622484  1164767  9818112    53576             0 panic
[  516.146977] [  10720]     0 10720  2622484  1174361  9904128    53709             0 panic
[  516.148163] [  10721]     0 10721  2622484  1209070 10194944    54824             0 panic
[  516.149329] [  10722]     0 10722  2622484  1745799 14774272    91138             0 panic

5) oom context (contrains and the chosen victim).

oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0-1,task=panic,pid=10737,uid=0

An admin can easily get the full oom context at a single line which
makes parsing much easier.

Link: http://lkml.kernel.org/r/1542799799-36184-1-git-send-email-ufo19890607@gmail.com
Signed-off-by: yuzhoujian <yuzhoujian@didichuxing.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <yang.s@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:48 -08:00
Alexey Dobriyan e5cb113f2d mm: make free_reserved_area() return "const char *"
and propagate through down the call stack.

Link: http://lkml.kernel.org/r/20181124091411.GC10969@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:48 -08:00
Alexey Dobriyan c999fbd3dc mm/mmzone.c: make "migratetype_names" const char *
Those strings are immutable in fact.

Link: http://lkml.kernel.org/r/20181124090327.GA10877@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:48 -08:00
Mel Gorman 1c30844d2d mm: reclaim small amounts of memory when an external fragmentation event occurs
An external fragmentation event was previously described as

    When the page allocator fragments memory, it records the event using
    the mm_page_alloc_extfrag event. If the fallback_order is smaller
    than a pageblock order (order-9 on 64-bit x86) then it's considered
    an event that will cause external fragmentation issues in the future.

The kernel reduces the probability of such events by increasing the
watermark sizes by calling set_recommended_min_free_kbytes early in the
lifetime of the system.  This works reasonably well in general but if
there are enough sparsely populated pageblocks then the problem can still
occur as enough memory is free overall and kswapd stays asleep.

This patch introduces a watermark_boost_factor sysctl that allows a zone
watermark to be temporarily boosted when an external fragmentation causing
events occurs.  The boosting will stall allocations that would decrease
free memory below the boosted low watermark and kswapd is woken if the
calling context allows to reclaim an amount of memory relative to the size
of the high watermark and the watermark_boost_factor until the boost is
cleared.  When kswapd finishes, it wakes kcompactd at the pageblock order
to clean some of the pageblocks that may have been affected by the
fragmentation event.  kswapd avoids any writeback, slab shrinkage and swap
from reclaim context during this operation to avoid excessive system
disruption in the name of fragmentation avoidance.  Care is taken so that
kswapd will do normal reclaim work if the system is really low on memory.

This was evaluated using the same workloads as "mm, page_alloc: Spread
allocations across zones before introducing fragmentation".

1-socket Skylake machine
config-global-dhp__workload_thpfioscale XFS (no special madvise)
4 fio threads, 1 THP allocating thread
--------------------------------------

4.20-rc3 extfrag events < order 9:   804694
4.20-rc3+patch:                      408912 (49% reduction)
4.20-rc3+patch1-4:                    18421 (98% reduction)

                                   4.20.0-rc3             4.20.0-rc3
                                 lowzone-v5r8             boost-v5r8
Amean     fault-base-1      653.58 (   0.00%)      652.71 (   0.13%)
Amean     fault-huge-1        0.00 (   0.00%)      178.93 * -99.00%*

                              4.20.0-rc3             4.20.0-rc3
                            lowzone-v5r8             boost-v5r8
Percentage huge-1        0.00 (   0.00%)        5.12 ( 100.00%)

Note that external fragmentation causing events are massively reduced by
this path whether in comparison to the previous kernel or the vanilla
kernel.  The fault latency for huge pages appears to be increased but that
is only because THP allocations were successful with the patch applied.

1-socket Skylake machine
global-dhp__workload_thpfioscale-madvhugepage-xfs (MADV_HUGEPAGE)
-----------------------------------------------------------------

4.20-rc3 extfrag events < order 9:  291392
4.20-rc3+patch:                     191187 (34% reduction)
4.20-rc3+patch1-4:                   13464 (95% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                 lowzone-v5r8             boost-v5r8
Min       fault-base-1      912.00 (   0.00%)      905.00 (   0.77%)
Min       fault-huge-1      127.00 (   0.00%)      135.00 (  -6.30%)
Amean     fault-base-1     1467.55 (   0.00%)     1481.67 (  -0.96%)
Amean     fault-huge-1     1127.11 (   0.00%)     1063.88 *   5.61%*

                              4.20.0-rc3             4.20.0-rc3
                            lowzone-v5r8             boost-v5r8
Percentage huge-1       77.64 (   0.00%)       83.46 (   7.49%)

As before, massive reduction in external fragmentation events, some jitter
on latencies and an increase in THP allocation success rates.

2-socket Haswell machine
config-global-dhp__workload_thpfioscale XFS (no special madvise)
4 fio threads, 5 THP allocating threads
----------------------------------------------------------------

4.20-rc3 extfrag events < order 9:  215698
4.20-rc3+patch:                     200210 (7% reduction)
4.20-rc3+patch1-4:                   14263 (93% reduction)

                                   4.20.0-rc3             4.20.0-rc3
                                 lowzone-v5r8             boost-v5r8
Amean     fault-base-5     1346.45 (   0.00%)     1306.87 (   2.94%)
Amean     fault-huge-5     3418.60 (   0.00%)     1348.94 (  60.54%)

                              4.20.0-rc3             4.20.0-rc3
                            lowzone-v5r8             boost-v5r8
Percentage huge-5        0.78 (   0.00%)        7.91 ( 910.64%)

There is a 93% reduction in fragmentation causing events, there is a big
reduction in the huge page fault latency and allocation success rate is
higher.

2-socket Haswell machine
global-dhp__workload_thpfioscale-madvhugepage-xfs (MADV_HUGEPAGE)
-----------------------------------------------------------------

4.20-rc3 extfrag events < order 9: 166352
4.20-rc3+patch:                    147463 (11% reduction)
4.20-rc3+patch1-4:                  11095 (93% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                 lowzone-v5r8             boost-v5r8
Amean     fault-base-5     6217.43 (   0.00%)     7419.67 * -19.34%*
Amean     fault-huge-5     3163.33 (   0.00%)     3263.80 (  -3.18%)

                              4.20.0-rc3             4.20.0-rc3
                            lowzone-v5r8             boost-v5r8
Percentage huge-5       95.14 (   0.00%)       87.98 (  -7.53%)

There is a large reduction in fragmentation events with some jitter around
the latencies and success rates.  As before, the high THP allocation
success rate does mean the system is under a lot of pressure.  However, as
the fragmentation events are reduced, it would be expected that the
long-term allocation success rate would be higher.

Link: http://lkml.kernel.org/r/20181123114528.28802-5-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:48 -08:00
Mel Gorman 0a79cdad5e mm: use alloc_flags to record if kswapd can wake
This is a preparation patch that copies the GFP flag __GFP_KSWAPD_RECLAIM
into alloc_flags.  This is a preparation patch only that avoids having to
pass gfp_mask through a long callchain in a future patch.

Note that the setting in the fast path happens in alloc_flags_nofragment()
and it may be claimed that this has nothing to do with ALLOC_NO_FRAGMENT.
That's true in this patch but is not true later so it's done now for
easier review to show where the flag needs to be recorded.

No functional change.

[mgorman@techsingularity.net: ALLOC_KSWAPD flag needs to be applied in the !CONFIG_ZONE_DMA32 case]
  Link: http://lkml.kernel.org/r/20181126143503.GO23260@techsingularity.net
Link: http://lkml.kernel.org/r/20181123114528.28802-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:48 -08:00
Mel Gorman a921444382 mm: move zone watermark accesses behind an accessor
This is a preparation patch only, no functional change.

Link: http://lkml.kernel.org/r/20181123114528.28802-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:48 -08:00
Mel Gorman 6bb154504f mm, page_alloc: spread allocations across zones before introducing fragmentation
Patch series "Fragmentation avoidance improvements", v5.

It has been noted before that fragmentation avoidance (aka
anti-fragmentation) is not perfect. Given sufficient time or an adverse
workload, memory gets fragmented and the long-term success of high-order
allocations degrades. This series defines an adverse workload, a definition
of external fragmentation events (including serious) ones and a series
that reduces the level of those fragmentation events.

The details of the workload and the consequences are described in more
detail in the changelogs. However, from patch 1, this is a high-level
summary of the adverse workload. The exact details are found in the
mmtests implementation.

The broad details of the workload are as follows;

1. Create an XFS filesystem (not specified in the configuration but done
   as part of the testing for this patch)
2. Start 4 fio threads that write a number of 64K files inefficiently.
   Inefficiently means that files are created on first access and not
   created in advance (fio parameterr create_on_open=1) and fallocate
   is not used (fallocate=none). With multiple IO issuers this creates
   a mix of slab and page cache allocations over time. The total size
   of the files is 150% physical memory so that the slabs and page cache
   pages get mixed
3. Warm up a number of fio read-only threads accessing the same files
   created in step 2. This part runs for the same length of time it
   took to create the files. It'll fault back in old data and further
   interleave slab and page cache allocations. As it's now low on
   memory due to step 2, fragmentation occurs as pageblocks get
   stolen.
4. While step 3 is still running, start a process that tries to allocate
   75% of memory as huge pages with a number of threads. The number of
   threads is based on a (NR_CPUS_SOCKET - NR_FIO_THREADS)/4 to avoid THP
   threads contending with fio, any other threads or forcing cross-NUMA
   scheduling. Note that the test has not been used on a machine with less
   than 8 cores. The benchmark records whether huge pages were allocated
   and what the fault latency was in microseconds
5. Measure the number of events potentially causing external fragmentation,
   the fault latency and the huge page allocation success rate.
6. Cleanup

Overall the series reduces external fragmentation causing events by over 94%
on 1 and 2 socket machines, which in turn impacts high-order allocation
success rates over the long term. There are differences in latencies and
high-order allocation success rates. Latencies are a mixed bag as they
are vulnerable to exact system state and whether allocations succeeded
so they are treated as a secondary metric.

Patch 1 uses lower zones if they are populated and have free memory
	instead of fragmenting a higher zone. It's special cased to
	handle a Normal->DMA32 fallback with the reasons explained
	in the changelog.

Patch 2-4 boosts watermarks temporarily when an external fragmentation
	event occurs. kswapd wakes to reclaim a small amount of old memory
	and then wakes kcompactd on completion to recover the system
	slightly. This introduces some overhead in the slowpath. The level
	of boosting can be tuned or disabled depending on the tolerance
	for fragmentation vs allocation latency.

Patch 5 stalls some movable allocation requests to let kswapd from patch 4
	make some progress. The duration of the stalls is very low but it
	is possible to tune the system to avoid fragmentation events if
	larger stalls can be tolerated.

The bulk of the improvement in fragmentation avoidance is from patches
1-4 but patch 5 can deal with a rare corner case and provides the option
of tuning a system for THP allocation success rates in exchange for
some stalls to control fragmentation.

This patch (of 5):

The page allocator zone lists are iterated based on the watermarks of each
zone which does not take anti-fragmentation into account.  On x86, node 0
may have multiple zones while other nodes have one zone.  A consequence is
that tasks running on node 0 may fragment ZONE_NORMAL even though
ZONE_DMA32 has plenty of free memory.  This patch special cases the
allocator fast path such that it'll try an allocation from a lower local
zone before fragmenting a higher zone.  In this case, stealing of
pageblocks or orders larger than a pageblock are still allowed in the fast
path as they are uninteresting from a fragmentation point of view.

This was evaluated using a benchmark designed to fragment memory before
attempting THP allocations.  It's implemented in mmtests as the following
configurations

configs/config-global-dhp__workload_thpfioscale
configs/config-global-dhp__workload_thpfioscale-defrag
configs/config-global-dhp__workload_thpfioscale-madvhugepage

e.g. from mmtests
./run-mmtests.sh --run-monitor --config configs/config-global-dhp__workload_thpfioscale test-run-1

The broad details of the workload are as follows;

1. Create an XFS filesystem (not specified in the configuration but done
   as part of the testing for this patch).
2. Start 4 fio threads that write a number of 64K files inefficiently.
   Inefficiently means that files are created on first access and not
   created in advance (fio parameter create_on_open=1) and fallocate
   is not used (fallocate=none). With multiple IO issuers this creates
   a mix of slab and page cache allocations over time. The total size
   of the files is 150% physical memory so that the slabs and page cache
   pages get mixed.
3. Warm up a number of fio read-only processes accessing the same files
   created in step 2. This part runs for the same length of time it
   took to create the files. It'll refault old data and further
   interleave slab and page cache allocations. As it's now low on
   memory due to step 2, fragmentation occurs as pageblocks get
   stolen.
4. While step 3 is still running, start a process that tries to allocate
   75% of memory as huge pages with a number of threads. The number of
   threads is based on a (NR_CPUS_SOCKET - NR_FIO_THREADS)/4 to avoid THP
   threads contending with fio, any other threads or forcing cross-NUMA
   scheduling. Note that the test has not been used on a machine with less
   than 8 cores. The benchmark records whether huge pages were allocated
   and what the fault latency was in microseconds.
5. Measure the number of events potentially causing external fragmentation,
   the fault latency and the huge page allocation success rate.
6. Cleanup the test files.

Note that due to the use of IO and page cache that this benchmark is not
suitable for running on large machines where the time to fragment memory
may be excessive.  Also note that while this is one mix that generates
fragmentation that it's not the only mix that generates fragmentation.
Differences in workload that are more slab-intensive or whether SLUB is
used with high-order pages may yield different results.

When the page allocator fragments memory, it records the event using the
mm_page_alloc_extfrag ftrace event.  If the fallback_order is smaller than
a pageblock order (order-9 on 64-bit x86) then it's considered to be an
"external fragmentation event" that may cause issues in the future.
Hence, the primary metric here is the number of external fragmentation
events that occur with order < 9.  The secondary metric is allocation
latency and huge page allocation success rates but note that differences
in latencies and what the success rate also can affect the number of
external fragmentation event which is why it's a secondary metric.

1-socket Skylake machine
config-global-dhp__workload_thpfioscale XFS (no special madvise)
4 fio threads, 1 THP allocating thread
--------------------------------------

4.20-rc3 extfrag events < order 9:   804694
4.20-rc3+patch:                      408912 (49% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                      vanilla           lowzone-v5r8
Amean     fault-base-1      662.92 (   0.00%)      653.58 *   1.41%*
Amean     fault-huge-1        0.00 (   0.00%)        0.00 (   0.00%)

                              4.20.0-rc3             4.20.0-rc3
                                 vanilla           lowzone-v5r8
Percentage huge-1        0.00 (   0.00%)        0.00 (   0.00%)

Fault latencies are slightly reduced while allocation success rates remain
at zero as this configuration does not make any special effort to allocate
THP and fio is heavily active at the time and either filling memory or
keeping pages resident.  However, a 49% reduction of serious fragmentation
events reduces the changes of external fragmentation being a problem in
the future.

Vlastimil asked during review for a breakdown of the allocation types
that are falling back.

vanilla
   3816 MIGRATE_UNMOVABLE
 800845 MIGRATE_MOVABLE
     33 MIGRATE_UNRECLAIMABLE

patch
    735 MIGRATE_UNMOVABLE
 408135 MIGRATE_MOVABLE
     42 MIGRATE_UNRECLAIMABLE

The majority of the fallbacks are due to movable allocations and this is
consistent for the workload throughout the series so will not be presented
again as the primary source of fallbacks are movable allocations.

Movable fallbacks are sometimes considered "ok" to fallback because they
can be migrated.  The problem is that they can fill an
unmovable/reclaimable pageblock causing those allocations to fallback
later and polluting pageblocks with pages that cannot move.  If there is a
movable fallback, it is pretty much guaranteed to affect an
unmovable/reclaimable pageblock and while it might not be enough to
actually cause a unmovable/reclaimable fallback in the future, we cannot
know that in advance so the patch takes the only option available to it.
Hence, it's important to control them.  This point is also consistent
throughout the series and will not be repeated.

1-socket Skylake machine
global-dhp__workload_thpfioscale-madvhugepage-xfs (MADV_HUGEPAGE)
-----------------------------------------------------------------

4.20-rc3 extfrag events < order 9:  291392
4.20-rc3+patch:                     191187 (34% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                      vanilla           lowzone-v5r8
Amean     fault-base-1     1495.14 (   0.00%)     1467.55 (   1.85%)
Amean     fault-huge-1     1098.48 (   0.00%)     1127.11 (  -2.61%)

thpfioscale Percentage Faults Huge
                              4.20.0-rc3             4.20.0-rc3
                                 vanilla           lowzone-v5r8
Percentage huge-1       78.57 (   0.00%)       77.64 (  -1.18%)

Fragmentation events were reduced quite a bit although this is known
to be a little variable. The latencies and allocation success rates
are similar but they were already quite high.

2-socket Haswell machine
config-global-dhp__workload_thpfioscale XFS (no special madvise)
4 fio threads, 5 THP allocating threads
----------------------------------------------------------------

4.20-rc3 extfrag events < order 9:  215698
4.20-rc3+patch:                     200210 (7% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                      vanilla           lowzone-v5r8
Amean     fault-base-5     1350.05 (   0.00%)     1346.45 (   0.27%)
Amean     fault-huge-5     4181.01 (   0.00%)     3418.60 (  18.24%)

                              4.20.0-rc3             4.20.0-rc3
                                 vanilla           lowzone-v5r8
Percentage huge-5        1.15 (   0.00%)        0.78 ( -31.88%)

The reduction of external fragmentation events is slight and this is
partially due to the removal of __GFP_THISNODE in commit ac5b2c1891
("mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings") as THP
allocations can now spill over to remote nodes instead of fragmenting
local memory.

2-socket Haswell machine
global-dhp__workload_thpfioscale-madvhugepage-xfs (MADV_HUGEPAGE)
-----------------------------------------------------------------

4.20-rc3 extfrag events < order 9: 166352
4.20-rc3+patch:                    147463 (11% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                      vanilla           lowzone-v5r8
Amean     fault-base-5     6138.97 (   0.00%)     6217.43 (  -1.28%)
Amean     fault-huge-5     2294.28 (   0.00%)     3163.33 * -37.88%*

thpfioscale Percentage Faults Huge
                              4.20.0-rc3             4.20.0-rc3
                                 vanilla           lowzone-v5r8
Percentage huge-5       96.82 (   0.00%)       95.14 (  -1.74%)

There was a slight reduction in external fragmentation events although the
latencies were higher.  The allocation success rate is high enough that
the system is struggling and there is quite a lot of parallel reclaim and
compaction activity.  There is also a certain degree of luck on whether
processes start on node 0 or not for this patch but the relevance is
reduced later in the series.

Overall, the patch reduces the number of external fragmentation causing
events so the success of THP over long periods of time would be improved
for this adverse workload.

Link: http://lkml.kernel.org/r/20181123114528.28802-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:48 -08:00
Aaron Lu 742aa7fb52 mm/page_alloc.c: use a single function to free page
There are multiple places of freeing a page, they all do the same things
so a common function can be used to reduce code duplicate.

It also avoids bug fixed in one function but left in another.

Link: http://lkml.kernel.org/r/20181119134834.17765-3-aaron.lu@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Pankaj gupta <pagupta@redhat.com>
Cc: Pawel Staszewski <pstaszewski@itcare.pl>
Cc: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:48 -08:00
Aaron Lu 65895b67ad mm/page_alloc.c: free order-0 pages through PCP in page_frag_free()
page_frag_free() calls __free_pages_ok() to free the page back to Buddy.
This is OK for high order page, but for order-0 pages, it misses the
optimization opportunity of using Per-Cpu-Pages and can cause zone lock
contention when called frequently.

Pawel Staszewski recently shared his result of 'how Linux kernel handles
normal traffic'[1] and from perf data, Jesper Dangaard Brouer found the
lock contention comes from page allocator:

  mlx5e_poll_tx_cq
  |
   --16.34%--napi_consume_skb
             |
             |--12.65%--__free_pages_ok
             |          |
             |           --11.86%--free_one_page
             |                     |
             |                     |--10.10%--queued_spin_lock_slowpath
             |                     |
             |                      --0.65%--_raw_spin_lock
             |
             |--1.55%--page_frag_free
             |
              --1.44%--skb_release_data

Jesper explained how it happened: mlx5 driver RX-page recycle mechanism is
not effective in this workload and pages have to go through the page
allocator.  The lock contention happens during mlx5 DMA TX completion
cycle.  And the page allocator cannot keep up at these speeds.[2]

I thought that __free_pages_ok() are mostly freeing high order pages and
thought this is an lock contention for high order pages but Jesper
explained in detail that __free_pages_ok() here are actually freeing
order-0 pages because mlx5 is using order-0 pages to satisfy its page pool
allocation request.[3]

The free path as pointed out by Jesper is:
skb_free_head()
  -> skb_free_frag()
    -> page_frag_free()
And the pages being freed on this path are order-0 pages.

Fix this by doing similar things as in __page_frag_cache_drain() - send
the being freed page to PCP if it's an order-0 page, or directly to Buddy
if it is a high order page.

With this change, Paweł hasn't noticed lock contention yet in his
workload and Jesper has noticed a 7% performance improvement using a micro
benchmark and lock contention is gone.  Ilias' test on a 'low' speed 1Gbit
interface on an cortex-a53 shows ~11% performance boost testing with
64byte packets and __free_pages_ok() disappeared from perf top.

[1]: https://www.spinics.net/lists/netdev/msg531362.html
[2]: https://www.spinics.net/lists/netdev/msg531421.html
[3]: https://www.spinics.net/lists/netdev/msg531556.html

[akpm@linux-foundation.org: add comment]
Link: http://lkml.kernel.org/r/20181120014544.GB10657@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reported-by: Pawel Staszewski <pstaszewski@itcare.pl>
Analysed-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Acked-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Pankaj gupta <pagupta@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:48 -08:00
Huang Shijie 7ead334215 mm/page_alloc.c: change the order of MIGRATE_RECLAIMABLE/MIGRATE_MOVABLE in fallbacks
In the enum migratetype definition, MIGRATE_MOVABLE is before
MIGRATE_RECLAIMABLE.  Change the order of them to match the enumeration's
order.

Link: http://lkml.kernel.org/r/20181121085821.3442-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Arun KS 476567e873 mm: remove managed_page_count_lock spinlock
Now that totalram_pages and managed_pages are atomic varibles, no need of
managed_page_count spinlock.  The lock had really a weak consistency
guarantee.  It hasn't been used for anything but the update but no reader
actually cares about all the values being updated to be in sync.

Link: http://lkml.kernel.org/r/1542090790-21750-5-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS <arunks@codeaurora.org>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Arun KS ca79b0c211 mm: convert totalram_pages and totalhigh_pages variables to atomic
totalram_pages and totalhigh_pages are made static inline function.

Main motivation was that managed_page_count_lock handling was complicating
things.  It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes
better to remove the lock and convert variables to atomic, with preventing
poteintial store-to-read tearing as a bonus.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS <arunks@codeaurora.org>
Suggested-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Arun KS 9705bea5f8 mm: convert zone->managed_pages to atomic variable
totalram_pages, zone->managed_pages and totalhigh_pages updates are
protected by managed_page_count_lock, but readers never care about it.
Convert these variables to atomic to avoid readers potentially seeing a
store tear.

This patch converts zone->managed_pages.  Subsequent patches will convert
totalram_panges, totalhigh_pages and eventually managed_page_count_lock
will be removed.

Main motivation was that managed_page_count_lock handling was complicating
things.  It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes
better to remove the lock and convert variables to atomic, with preventing
poteintial store-to-read tearing as a bonus.

Link: http://lkml.kernel.org/r/1542090790-21750-3-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS <arunks@codeaurora.org>
Suggested-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Arun KS 3d6357de8a mm: reference totalram_pages and managed_pages once per function
Patch series "mm: convert totalram_pages, totalhigh_pages and managed
pages to atomic", v5.

This series converts totalram_pages, totalhigh_pages and
zone->managed_pages to atomic variables.

totalram_pages, zone->managed_pages and totalhigh_pages updates are
protected by managed_page_count_lock, but readers never care about it.
Convert these variables to atomic to avoid readers potentially seeing a
store tear.

Main motivation was that managed_page_count_lock handling was complicating
things.  It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 It seemes better
to remove the lock and convert variables to atomic.  With the change,
preventing poteintial store-to-read tearing comes as a bonus.

This patch (of 4):

This is in preparation to a later patch which converts totalram_pages and
zone->managed_pages to atomic variables.  Please note that re-reading the
value might lead to a different value and as such it could lead to
unexpected behavior.  There are no known bugs as a result of the current
code but it is better to prevent from them in principle.

Link: http://lkml.kernel.org/r/1542090790-21750-2-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS <arunks@codeaurora.org>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Wei Yang fecd4a50ba mm: remove reset of pcp->counter in pageset_init()
per_cpu_pageset is cleared by memset, it is not necessary to reset it
again.

Link: http://lkml.kernel.org/r/20181021023920.5501-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Michal Hocko d381c54760 mm: only report isolation failures when offlining memory
Heiko has complained that his log is swamped by warnings from
has_unmovable_pages

[   20.536664] page dumped because: has_unmovable_pages
[   20.536792] page:000003d081ff4080 count:1 mapcount:0 mapping:000000008ff88600 index:0x0 compound_mapcount: 0
[   20.536794] flags: 0x3fffe0000010200(slab|head)
[   20.536795] raw: 03fffe0000010200 0000000000000100 0000000000000200 000000008ff88600
[   20.536796] raw: 0000000000000000 0020004100000000 ffffffff00000001 0000000000000000
[   20.536797] page dumped because: has_unmovable_pages
[   20.536814] page:000003d0823b0000 count:1 mapcount:0 mapping:0000000000000000 index:0x0
[   20.536815] flags: 0x7fffe0000000000()
[   20.536817] raw: 07fffe0000000000 0000000000000100 0000000000000200 0000000000000000
[   20.536818] raw: 0000000000000000 0000000000000000 ffffffff00000001 0000000000000000

which are not triggered by the memory hotplug but rather CMA allocator.
The original idea behind dumping the page state for all call paths was
that these messages will be helpful debugging failures.  From the above it
seems that this is not the case for the CMA path because we are lacking
much more context.  E.g the second reported page might be a CMA allocated
page.  It is still interesting to see a slab page in the CMA area but it
is hard to tell whether this is bug from the above output alone.

Address this issue by dumping the page state only on request.  Both
start_isolate_page_range and has_unmovable_pages already have an argument
to ignore hwpoison pages so make this argument more generic and turn it
into flags and allow callers to combine non-default modes into a mask.
While we are at it, has_unmovable_pages call from
is_pageblock_removable_nolock (sysfs removable file) is questionable to
report the failure so drop it from there as well.

Link: http://lkml.kernel.org/r/20181218092802.31429-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:46 -08:00
Michal Hocko 2932c8b050 mm, memory_hotplug: be more verbose for memory offline failures
There is only very limited information printed when the memory offlining
fails:

[ 1984.506184] rac1 kernel: memory offlining [mem 0x82600000000-0x8267fffffff] failed due to signal backoff

This tells us that the failure is triggered by the userspace intervention
but it doesn't tell us much more about the underlying reason.  It might be
that the page migration failes repeatedly and the userspace timeout
expires and send a signal or it might be some of the earlier steps
(isolation, memory notifier) takes too long.

If the migration failes then it would be really helpful to see which page
that and its state.  The same applies to the isolation phase.  If we fail
to isolate a page from the allocator then knowing the state of the page
would be helpful as well.

Dump the page state that fails to get isolated or migrated.  This will
tell us more about the failure and what to focus on during debugging.

[akpm@linux-foundation.org: add missing printk arg]
[mhocko@suse.com: tweak dump_page() `reason' text]
  Link: http://lkml.kernel.org/r/20181116083020.20260-6-mhocko@kernel.org
Link: http://lkml.kernel.org/r/20181107101830.17405-6-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Oscar Salvador <OSalvador@suse.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:46 -08:00
Andrey Konovalov 2813b9c029 kasan, mm, arm64: tag non slab memory allocated via pagealloc
Tag-based KASAN doesn't check memory accesses through pointers tagged with
0xff.  When page_address is used to get pointer to memory that corresponds
to some page, the tag of the resulting pointer gets set to 0xff, even
though the allocated memory might have been tagged differently.

For slab pages it's impossible to recover the correct tag to return from
page_address, since the page might contain multiple slab objects tagged
with different values, and we can't know in advance which one of them is
going to get accessed.  For non slab pages however, we can recover the tag
in page_address, since the whole page was marked with the same tag.

This patch adds tagging to non slab memory allocated with pagealloc.  To
set the tag of the pointer returned from page_address, the tag gets stored
to page->flags when the memory gets allocated.

Link: http://lkml.kernel.org/r/d758ddcef46a5abc9970182b9137e2fbee202a2c.1544099024.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:44 -08:00
Oscar Salvador 17e2e7d7e1 mm, page_alloc: fix has_unmovable_pages for HugePages
While playing with gigantic hugepages and memory_hotplug, I triggered
the following #PF when "cat memoryX/removable":

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  #PF error: [normal kernel read fault]
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP PTI
  CPU: 1 PID: 1481 Comm: cat Tainted: G            E     4.20.0-rc6-mm1-1-default+ #18
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014
  RIP: 0010:has_unmovable_pages+0x154/0x210
  Call Trace:
   is_mem_section_removable+0x7d/0x100
   removable_show+0x90/0xb0
   dev_attr_show+0x1c/0x50
   sysfs_kf_seq_show+0xca/0x1b0
   seq_read+0x133/0x380
   __vfs_read+0x26/0x180
   vfs_read+0x89/0x140
   ksys_read+0x42/0x90
   do_syscall_64+0x5b/0x180
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

The reason is we do not pass the Head to page_hstate(), and so, the call
to compound_order() in page_hstate() returns 0, so we end up checking
all hstates's size to match PAGE_SIZE.

Obviously, we do not find any hstate matching that size, and we return
NULL.  Then, we dereference that NULL pointer in
hugepage_migration_supported() and we got the #PF from above.

Fix that by getting the head page before calling page_hstate().

Also, since gigantic pages span several pageblocks, re-adjust the logic
for skipping pages.  While are it, we can also get rid of the
round_up().

[osalvador@suse.de: remove round_up(), adjust skip pages logic per Michal]
  Link: http://lkml.kernel.org/r/20181221062809.31771-1-osalvador@suse.de
Link: http://lkml.kernel.org/r/20181217225113.17864-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-21 14:51:18 -08:00
Mikhail Zaslonko 2830bf6f05 mm, memory_hotplug: initialize struct pages for the full memory section
If memory end is not aligned with the sparse memory section boundary,
the mapping of such a section is only partly initialized.  This may lead
to VM_BUG_ON due to uninitialized struct page access from
is_mem_section_removable() or test_pages_in_a_zone() function triggered
by memory_hotplug sysfs handlers:

Here are the the panic examples:
 CONFIG_DEBUG_VM=y
 CONFIG_DEBUG_VM_PGFLAGS=y

 kernel parameter mem=2050M
 --------------------------
 page:000003d082008000 is uninitialized and poisoned
 page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
 Call Trace:
 ( test_pages_in_a_zone+0xde/0x160)
   show_valid_zones+0x5c/0x190
   dev_attr_show+0x34/0x70
   sysfs_kf_seq_show+0xc8/0x148
   seq_read+0x204/0x480
   __vfs_read+0x32/0x178
   vfs_read+0x82/0x138
   ksys_read+0x5a/0xb0
   system_call+0xdc/0x2d8
 Last Breaking-Event-Address:
   test_pages_in_a_zone+0xde/0x160
 Kernel panic - not syncing: Fatal exception: panic_on_oops

 kernel parameter mem=3075M
 --------------------------
 page:000003d08300c000 is uninitialized and poisoned
 page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
 Call Trace:
 ( is_mem_section_removable+0xb4/0x190)
   show_mem_removable+0x9a/0xd8
   dev_attr_show+0x34/0x70
   sysfs_kf_seq_show+0xc8/0x148
   seq_read+0x204/0x480
   __vfs_read+0x32/0x178
   vfs_read+0x82/0x138
   ksys_read+0x5a/0xb0
   system_call+0xdc/0x2d8
 Last Breaking-Event-Address:
   is_mem_section_removable+0xb4/0x190
 Kernel panic - not syncing: Fatal exception: panic_on_oops

Fix the problem by initializing the last memory section of each zone in
memmap_init_zone() till the very end, even if it goes beyond the zone end.

Michal said:

: This has alwways been problem AFAIU.  It just went unnoticed because we
: have zeroed memmaps during allocation before f7f99100d8 ("mm: stop
: zeroing memory during allocation in vmemmap") and so the above test
: would simply skip these ranges as belonging to zone 0 or provided a
: garbage.
:
: So I guess we do care for post f7f99100d8 kernels mostly and
: therefore Fixes: f7f99100d8 ("mm: stop zeroing memory during
: allocation in vmemmap")

Link: http://lkml.kernel.org/r/20181212172712.34019-2-zaslonko@linux.ibm.com
Fixes: f7f99100d8 ("mm: stop zeroing memory during allocation in vmemmap")
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Suggested-by: Michal Hocko <mhocko@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-21 14:51:18 -08:00
Wei Yang 8f416836c0 mm/page_alloc.c: fix calculation of pgdat->nr_zones
init_currently_empty_zone() will adjust pgdat->nr_zones and set it to
'zone_idx(zone) + 1' unconditionally.  This is correct in the normal
case, while not exact in hot-plug situation.

This function is used in two places:

  * free_area_init_core()
  * move_pfn_range_to_zone()

In the first case, we are sure zone index increase monotonically.  While
in the second one, this is under users control.

One way to reproduce this is:
----------------------------

1. create a virtual machine with empty node1

   -m 4G,slots=32,maxmem=32G \
   -smp 4,maxcpus=8          \
   -numa node,nodeid=0,mem=4G,cpus=0-3 \
   -numa node,nodeid=1,mem=0G,cpus=4-7

2. hot-add cpu 3-7

   cpu-add [3-7]

2. hot-add memory to nod1

   object_add memory-backend-ram,id=ram0,size=1G
   device_add pc-dimm,id=dimm0,memdev=ram0,node=1

3. online memory with following order

   echo online_movable > memory47/state
   echo online > memory40/state

After this, node1 will have its nr_zones equals to (ZONE_NORMAL + 1)
instead of (ZONE_MOVABLE + 1).

Michal said:
 "Having an incorrect nr_zones might result in all sorts of problems
  which would be quite hard to debug (e.g. reclaim not considering the
  movable zone). I do not expect many users would suffer from this it
  but still this is trivial and obviously right thing to do so
  backporting to the stable tree shouldn't be harmful (last famous
  words)"

Link: http://lkml.kernel.org/r/20181117022022.9956-1-richard.weiyang@gmail.com
Fixes: f1dd2cd13c ("mm, memory_hotplug: do not associate hotadded memory to zones until online")
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-30 14:56:14 -08:00
Michal Hocko c63ae43ba5 mm, page_alloc: check for max order in hot path
Konstantin has noticed that kvmalloc might trigger the following
warning:

  WARNING: CPU: 0 PID: 6676 at mm/vmstat.c:986 __fragmentation_index+0x54/0x60
  [...]
  Call Trace:
   fragmentation_index+0x76/0x90
   compaction_suitable+0x4f/0xf0
   shrink_node+0x295/0x310
   node_reclaim+0x205/0x250
   get_page_from_freelist+0x649/0xad0
   __alloc_pages_nodemask+0x12a/0x2a0
   kmalloc_large_node+0x47/0x90
   __kmalloc_node+0x22b/0x2e0
   kvmalloc_node+0x3e/0x70
   xt_alloc_table_info+0x3a/0x80 [x_tables]
   do_ip6t_set_ctl+0xcd/0x1c0 [ip6_tables]
   nf_setsockopt+0x44/0x60
   SyS_setsockopt+0x6f/0xc0
   do_syscall_64+0x67/0x120
   entry_SYSCALL_64_after_hwframe+0x3d/0xa2

the problem is that we only check for an out of bound order in the slow
path and the node reclaim might happen from the fast path already.  This
is fixable by making sure that kvmalloc doesn't ever use kmalloc for
requests that are larger than KMALLOC_MAX_SIZE but this also shows that
the code is rather fragile.  A recent UBSAN report just underlines that
by the following report

  UBSAN: Undefined behaviour in mm/page_alloc.c:3117:19
  shift exponent 51 is too large for 32-bit type 'int'
  CPU: 0 PID: 6520 Comm: syz-executor1 Not tainted 4.19.0-rc2 #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Call Trace:
   __dump_stack lib/dump_stack.c:77 [inline]
   dump_stack+0xd2/0x148 lib/dump_stack.c:113
   ubsan_epilogue+0x12/0x94 lib/ubsan.c:159
   __ubsan_handle_shift_out_of_bounds+0x2b6/0x30b lib/ubsan.c:425
   __zone_watermark_ok+0x2c7/0x400 mm/page_alloc.c:3117
   zone_watermark_fast mm/page_alloc.c:3216 [inline]
   get_page_from_freelist+0xc49/0x44c0 mm/page_alloc.c:3300
   __alloc_pages_nodemask+0x21e/0x640 mm/page_alloc.c:4370
   alloc_pages_current+0xcc/0x210 mm/mempolicy.c:2093
   alloc_pages include/linux/gfp.h:509 [inline]
   __get_free_pages+0x12/0x60 mm/page_alloc.c:4414
   dma_mem_alloc+0x36/0x50 arch/x86/include/asm/floppy.h:156
   raw_cmd_copyin drivers/block/floppy.c:3159 [inline]
   raw_cmd_ioctl drivers/block/floppy.c:3206 [inline]
   fd_locked_ioctl+0xa00/0x2c10 drivers/block/floppy.c:3544
   fd_ioctl+0x40/0x60 drivers/block/floppy.c:3571
   __blkdev_driver_ioctl block/ioctl.c:303 [inline]
   blkdev_ioctl+0xb3c/0x1a30 block/ioctl.c:601
   block_ioctl+0x105/0x150 fs/block_dev.c:1883
   vfs_ioctl fs/ioctl.c:46 [inline]
   do_vfs_ioctl+0x1c0/0x1150 fs/ioctl.c:687
   ksys_ioctl+0x9e/0xb0 fs/ioctl.c:702
   __do_sys_ioctl fs/ioctl.c:709 [inline]
   __se_sys_ioctl fs/ioctl.c:707 [inline]
   __x64_sys_ioctl+0x7e/0xc0 fs/ioctl.c:707
   do_syscall_64+0xc4/0x510 arch/x86/entry/common.c:290
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Note that this is not a kvmalloc path.  It is just that the fast path
really depends on having sanitzed order as well.  Therefore move the
order check to the fast path.

Link: http://lkml.kernel.org/r/20181113094305.GM15120@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reported-by: Kyungtae Kim <kt0755@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Byoungyoung Lee <lifeasageek@gmail.com>
Cc: "Dae R. Jeong" <threeearcat@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-18 10:15:10 -08:00
Michal Hocko 9d7899999c mm, memory_hotplug: check zone_movable in has_unmovable_pages
Page state checks are racy.  Under a heavy memory workload (e.g.  stress
-m 200 -t 2h) it is quite easy to hit a race window when the page is
allocated but its state is not fully populated yet.  A debugging patch to
dump the struct page state shows

  has_unmovable_pages: pfn:0x10dfec00, found:0x1, count:0x0
  page:ffffea0437fb0000 count:1 mapcount:1 mapping:ffff880e05239841 index:0x7f26e5000 compound_mapcount: 1
  flags: 0x5fffffc0090034(uptodate|lru|active|head|swapbacked)

Note that the state has been checked for both PageLRU and PageSwapBacked
already.  Closing this race completely would require some sort of retry
logic.  This can be tricky and error prone (think of potential endless
or long taking loops).

Workaround this problem for movable zones at least.  Such a zone should
only contain movable pages.  Commit 15c30bc090 ("mm, memory_hotplug:
make has_unmovable_pages more robust") has told us that this is not
strictly true though.  Bootmem pages should be marked reserved though so
we can move the original check after the PageReserved check.  Pages from
other zones are still prone to races but we even do not pretend that
memory hotremove works for those so pre-mature failure doesn't hurt that
much.

Link: http://lkml.kernel.org/r/20181106095524.14629-1-mhocko@kernel.org
Fixes: 15c30bc090 ("mm, memory_hotplug: make has_unmovable_pages more robust")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Baoquan He <bhe@redhat.com>
Tested-by: Baoquan He <bhe@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-18 10:15:09 -08:00
Mike Rapoport 7e1c4e2792 memblock: stop using implicit alignment to SMP_CACHE_BYTES
When a memblock allocation APIs are called with align = 0, the alignment
is implicitly set to SMP_CACHE_BYTES.

Implicit alignment is done deep in the memblock allocator and it can
come as a surprise.  Not that such an alignment would be wrong even
when used incorrectly but it is better to be explicit for the sake of
clarity and the prinicple of the least surprise.

Replace all such uses of memblock APIs with the 'align' parameter
explicitly set to SMP_CACHE_BYTES and stop implicit alignment assignment
in the memblock internal allocation functions.

For the case when memblock APIs are used via helper functions, e.g.  like
iommu_arena_new_node() in Alpha, the helper functions were detected with
Coccinelle's help and then manually examined and updated where
appropriate.

The direct memblock APIs users were updated using the semantic patch below:

@@
expression size, min_addr, max_addr, nid;
@@
(
|
- memblock_alloc_try_nid_raw(size, 0, min_addr, max_addr, nid)
+ memblock_alloc_try_nid_raw(size, SMP_CACHE_BYTES, min_addr, max_addr,
nid)
|
- memblock_alloc_try_nid_nopanic(size, 0, min_addr, max_addr, nid)
+ memblock_alloc_try_nid_nopanic(size, SMP_CACHE_BYTES, min_addr, max_addr,
nid)
|
- memblock_alloc_try_nid(size, 0, min_addr, max_addr, nid)
+ memblock_alloc_try_nid(size, SMP_CACHE_BYTES, min_addr, max_addr, nid)
|
- memblock_alloc(size, 0)
+ memblock_alloc(size, SMP_CACHE_BYTES)
|
- memblock_alloc_raw(size, 0)
+ memblock_alloc_raw(size, SMP_CACHE_BYTES)
|
- memblock_alloc_from(size, 0, min_addr)
+ memblock_alloc_from(size, SMP_CACHE_BYTES, min_addr)
|
- memblock_alloc_nopanic(size, 0)
+ memblock_alloc_nopanic(size, SMP_CACHE_BYTES)
|
- memblock_alloc_low(size, 0)
+ memblock_alloc_low(size, SMP_CACHE_BYTES)
|
- memblock_alloc_low_nopanic(size, 0)
+ memblock_alloc_low_nopanic(size, SMP_CACHE_BYTES)
|
- memblock_alloc_from_nopanic(size, 0, min_addr)
+ memblock_alloc_from_nopanic(size, SMP_CACHE_BYTES, min_addr)
|
- memblock_alloc_node(size, 0, nid)
+ memblock_alloc_node(size, SMP_CACHE_BYTES, nid)
)

[mhocko@suse.com: changelog update]
[akpm@linux-foundation.org: coding-style fixes]
[rppt@linux.ibm.com: fix missed uses of implicit alignment]
  Link: http://lkml.kernel.org/r/20181016133656.GA10925@rapoport-lnx
Link: http://lkml.kernel.org/r/1538687224-17535-1-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Paul Burton <paul.burton@mips.com>	[MIPS]
Acked-by: Michael Ellerman <mpe@ellerman.id.au>	[powerpc]
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31 08:54:16 -07:00
Mike Rapoport 57c8a661d9 mm: remove include/linux/bootmem.h
Move remaining definitions and declarations from include/linux/bootmem.h
into include/linux/memblock.h and remove the redundant header.

The includes were replaced with the semantic patch below and then
semi-automated removal of duplicated '#include <linux/memblock.h>

@@
@@
- #include <linux/bootmem.h>
+ #include <linux/memblock.h>

[sfr@canb.auug.org.au: dma-direct: fix up for the removal of linux/bootmem.h]
  Link: http://lkml.kernel.org/r/20181002185342.133d1680@canb.auug.org.au
[sfr@canb.auug.org.au: powerpc: fix up for removal of linux/bootmem.h]
  Link: http://lkml.kernel.org/r/20181005161406.73ef8727@canb.auug.org.au
[sfr@canb.auug.org.au: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal]
  Link: http://lkml.kernel.org/r/20181008190341.5e396491@canb.auug.org.au
Link: http://lkml.kernel.org/r/1536927045-23536-30-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31 08:54:16 -07:00
Mike Rapoport 7c2ee349cf memblock: rename __free_pages_bootmem to memblock_free_pages
The conversion is done using

sed -i 's@__free_pages_bootmem@memblock_free_pages@' \
    $(git grep -l __free_pages_bootmem)

Link: http://lkml.kernel.org/r/1536927045-23536-27-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31 08:54:16 -07:00
Mike Rapoport c6ffc5ca8f memblock: rename free_all_bootmem to memblock_free_all
The conversion is done using

sed -i 's@free_all_bootmem@memblock_free_all@' \
    $(git grep -l free_all_bootmem)

Link: http://lkml.kernel.org/r/1536927045-23536-26-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31 08:54:16 -07:00
Mike Rapoport eb31d559f1 memblock: remove _virt from APIs returning virtual address
The conversion is done using

sed -i 's@memblock_virt_alloc@memblock_alloc@g' \
	$(git grep -l memblock_virt_alloc)

Link: http://lkml.kernel.org/r/1536927045-23536-8-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31 08:54:15 -07:00
Mike Rapoport aca52c3983 mm: remove CONFIG_HAVE_MEMBLOCK
All architecures use memblock for early memory management. There is no need
for the CONFIG_HAVE_MEMBLOCK configuration option.

[rppt@linux.vnet.ibm.com: of/fdt: fixup #ifdefs]
  Link: http://lkml.kernel.org/r/20180919103457.GA20545@rapoport-lnx
[rppt@linux.vnet.ibm.com: csky: fixups after bootmem removal]
  Link: http://lkml.kernel.org/r/20180926112744.GC4628@rapoport-lnx
[rppt@linux.vnet.ibm.com: remove stale #else and the code it protects]
  Link: http://lkml.kernel.org/r/1538067825-24835-1-git-send-email-rppt@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1536927045-23536-4-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31 08:54:15 -07:00
Pavel Tatashin ec393a0f01 mm: return zero_resv_unavail optimization
When checking for valid pfns in zero_resv_unavail(), it is not necessary
to verify that pfns within pageblock_nr_pages ranges are valid, only the
first one needs to be checked.  This is because memory for pages are
allocated in contiguous chunks that contain pageblock_nr_pages struct
pages.

Link: http://lkml.kernel.org/r/20181002143821.5112-3-msys.mizuma@gmail.com
Signed-off-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Reviewed-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:38:15 -07:00
Naoya Horiguchi 907ec5fca3 mm: zero remaining unavailable struct pages
Patch series "mm: Fix for movable_node boot option", v3.

This patch series contains a fix for the movable_node boot option issue
which was introduced by commit 124049decb ("x86/e820: put !E820_TYPE_RAM
regions into memblock.reserved").

The commit breaks the option because it changed the memory gap range to
reserved memblock.  So, the node is marked as Normal zone even if the SRAT
has Hot pluggable affinity.

First and second patch fix the original issue which the commit tried to
fix, then revert the commit.

This patch (of 3):

There is a kernel panic that is triggered when reading /proc/kpageflags on
the kernel booted with kernel parameter 'memmap=nn[KMG]!ss[KMG]':

  BUG: unable to handle kernel paging request at fffffffffffffffe
  PGD 9b20e067 P4D 9b20e067 PUD 9b210067 PMD 0
  Oops: 0000 [#1] SMP PTI
  CPU: 2 PID: 1728 Comm: page-types Not tainted 4.17.0-rc6-mm1-v4.17-rc6-180605-0816-00236-g2dfb086ef02c+ #160
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.fc28 04/01/2014
  RIP: 0010:stable_page_flags+0x27/0x3c0
  Code: 00 00 00 0f 1f 44 00 00 48 85 ff 0f 84 a0 03 00 00 41 54 55 49 89 fc 53 48 8b 57 08 48 8b 2f 48 8d 42 ff 83 e2 01 48 0f 44 c7 <48> 8b 00 f6 c4 01 0f 84 10 03 00 00 31 db 49 8b 54 24 08 4c 89 e7
  RSP: 0018:ffffbbd44111fde0 EFLAGS: 00010202
  RAX: fffffffffffffffe RBX: 00007fffffffeff9 RCX: 0000000000000000
  RDX: 0000000000000001 RSI: 0000000000000202 RDI: ffffed1182fff5c0
  RBP: ffffffffffffffff R08: 0000000000000001 R09: 0000000000000001
  R10: ffffbbd44111fed8 R11: 0000000000000000 R12: ffffed1182fff5c0
  R13: 00000000000bffd7 R14: 0000000002fff5c0 R15: ffffbbd44111ff10
  FS:  00007efc4335a500(0000) GS:ffff93a5bfc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: fffffffffffffffe CR3: 00000000b2a58000 CR4: 00000000001406e0
  Call Trace:
   kpageflags_read+0xc7/0x120
   proc_reg_read+0x3c/0x60
   __vfs_read+0x36/0x170
   vfs_read+0x89/0x130
   ksys_pread64+0x71/0x90
   do_syscall_64+0x5b/0x160
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7efc42e75e23
  Code: 09 00 ba 9f 01 00 00 e8 ab 81 f4 ff 66 2e 0f 1f 84 00 00 00 00 00 90 83 3d 29 0a 2d 00 00 75 13 49 89 ca b8 11 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 db d3 01 00 48 89 04 24

According to kernel bisection, this problem became visible due to commit
f7f99100d8 which changes how struct pages are initialized.

Memblock layout affects the pfn ranges covered by node/zone.  Consider
that we have a VM with 2 NUMA nodes and each node has 4GB memory, and the
default (no memmap= given) memblock layout is like below:

  MEMBLOCK configuration:
   memory size = 0x00000001fff75c00 reserved size = 0x000000000300c000
   memory.cnt  = 0x4
   memory[0x0]     [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0
   memory[0x1]     [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0
   memory[0x2]     [0x0000000100000000-0x000000013fffffff], 0x0000000040000000 bytes on node 0 flags: 0x0
   memory[0x3]     [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0
   ...

If you give memmap=1G!4G (so it just covers memory[0x2]),
the range [0x100000000-0x13fffffff] is gone:

  MEMBLOCK configuration:
   memory size = 0x00000001bff75c00 reserved size = 0x000000000300c000
   memory.cnt  = 0x3
   memory[0x0]     [0x0000000000001000-0x000000000009efff], 0x000000000009e000 bytes on node 0 flags: 0x0
   memory[0x1]     [0x0000000000100000-0x00000000bffd6fff], 0x00000000bfed7000 bytes on node 0 flags: 0x0
   memory[0x2]     [0x0000000140000000-0x000000023fffffff], 0x0000000100000000 bytes on node 1 flags: 0x0
   ...

This causes shrinking node 0's pfn range because it is calculated by the
address range of memblock.memory.  So some of struct pages in the gap
range are left uninitialized.

We have a function zero_resv_unavail() which does zeroing the struct pages
outside memblock.memory, but currently it covers only the reserved
unavailable range (i.e.  memblock.memory && !memblock.reserved).  This
patch extends it to cover all unavailable range, which fixes the reported
issue.

Link: http://lkml.kernel.org/r/20181002143821.5112-2-msys.mizuma@gmail.com
Fixes: f7f99100d8 ("mm: stop zeroing memory during allocation in vmemmap")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Tested-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:38:15 -07:00
Pavel Tatashin a9a9e77fbf mm: move mirrored memory specific code outside of memmap_init_zone
memmap_init_zone, is getting complex, because it is called from different
contexts: hotplug, and during boot, and also because it must handle some
architecture quirks.  One of them is mirrored memory.

Move the code that decides whether to skip mirrored memory outside of
memmap_init_zone, into a separate function.

[pasha.tatashin@oracle.com: uninline overlap_memmap_init()]
  Link: http://lkml.kernel.org/r/20180726193509.3326-4-pasha.tatashin@oracle.com
Link: http://lkml.kernel.org/r/20180724235520.10200-4-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:38:10 -07:00
Pavel Tatashin d3035be4ce mm: calculate deferred pages after skipping mirrored memory
update_defer_init() should be called only when struct page is about to be
initialized. Because it counts number of initialized struct pages, but
there we may skip struct pages if there is some mirrored memory.

So move, update_defer_init() after checking for mirrored memory.

Also, rename update_defer_init() to defer_init() and reverse the return
boolean to emphasize that this is a boolean function, that tells that the
reset of memmap initialization should be deferred.

Make this function self-contained: do not pass number of already
initialized pages in this zone by using static counters.

I found this bug by reading the code.  The effect is that fewer than
expected struct pages are initialized early in boot, and it is possible
that in some corner cases we may fail to boot when mirrored pages are
used.  The deferred on demand code should somewhat mitigate this.  But
this still brings some inconsistencies compared to when booting without
mirrored pages, so it is better to fix.

[pasha.tatashin@oracle.com: add comment about defer_init's lack of locking]
  Link: http://lkml.kernel.org/r/20180726193509.3326-3-pasha.tatashin@oracle.com
[akpm@linux-foundation.org: make defer_init non-inline, __meminit]
Link: http://lkml.kernel.org/r/20180724235520.10200-3-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:26:35 -07:00
Pavel Tatashin dfb3ccd00a mm: make memmap_init a proper function
memmap_init is sometimes a macro sometimes a function based on
__HAVE_ARCH_MEMMAP_INIT.  It is only a function on ia64.  Make memmap_init
a weak function instead, and let ia64 redefine it.

Link: http://lkml.kernel.org/r/20180724235520.10200-2-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:26:35 -07:00
David Rientjes 4a222127f3 mm/page_alloc.c: initialize num_movable in move_freepages()
If move_freepages_block() returns 0 because !zone_spans_pfn(),
*num_movable can hold the value from the stack because it does not get
initialized in move_freepages().

Move the initialization to move_freepages_block() to guarantee the value
actually makes sense.

This currently doesn't affect its only caller where num_movable != NULL,
so no bug fix, but just more robust.

Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1810051355490.212229@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:26:35 -07:00
Alexander Duyck 966cf44f63 mm: defer ZONE_DEVICE page initialization to the point where we init pgmap
The ZONE_DEVICE pages were being initialized in two locations.  One was
with the memory_hotplug lock held and another was outside of that lock.
The problem with this is that it was nearly doubling the memory
initialization time.  Instead of doing this twice, once while holding a
global lock and once without, I am opting to defer the initialization to
the one outside of the lock.  This allows us to avoid serializing the
overhead for memory init and we can instead focus on per-node init times.

One issue I encountered is that devm_memremap_pages and
hmm_devmmem_pages_create were initializing only the pgmap field the same
way.  One wasn't initializing hmm_data, and the other was initializing it
to a poison value.  Since this is something that is exposed to the driver
in the case of hmm I am opting for a third option and just initializing
hmm_data to 0 since this is going to be exposed to unknown third party
drivers.

[alexander.h.duyck@linux.intel.com: fix reference count for pgmap in devm_memremap_pages]
  Link: http://lkml.kernel.org/r/20181008233404.1909.37302.stgit@localhost.localdomain
Link: http://lkml.kernel.org/r/20180925202053.3576.66039.stgit@localhost.localdomain
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:26:34 -07:00
Alexander Duyck d483da5bc7 mm: create non-atomic version of SetPageReserved for init use
It doesn't make much sense to use the atomic SetPageReserved at init time
when we are using memset to clear the memory and manipulating the page
flags via simple "&=" and "|=" operations in __init_single_page.

This patch adds a non-atomic version __SetPageReserved that can be used
during page init and shows about a 10% improvement in initialization times
on the systems I have available for testing.  On those systems I saw
initialization times drop from around 35 seconds to around 32 seconds to
initialize a 3TB block of persistent memory.  I believe the main advantage
of this is that it allows for more compiler optimization as the __set_bit
operation can be reordered whereas the atomic version cannot.

I tried adding a bit of documentation based on f1dd2cd13c ("mm,
memory_hotplug: do not associate hotadded memory to zones until online").

Ideally the reserved flag should be set earlier since there is a brief
window where the page is initialization via __init_single_page and we have
not set the PG_Reserved flag.  I'm leaving that for a future patch set as
that will require a more significant refactor.

Link: http://lkml.kernel.org/r/20180925202018.3576.11607.stgit@localhost.localdomain
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:26:34 -07:00
Michal Hocko 2c029a1ea3 mm, page_alloc: drop should_suppress_show_mem
should_suppress_show_mem() was introduced to reduce the overhead of
show_mem on large NUMA systems.  Things have changed since then though.
Namely c78e93630d ("mm: do not walk all of system memory during
show_mem") has reduced the overhead considerably.

Moreover warn_alloc_show_mem clears SHOW_MEM_FILTER_NODES when called from
the IRQ context already so we are not printing per node stats.

Remove should_suppress_show_mem because we are losing potentially
interesting information about allocation failures.  We have seen a bug
report where system gets unresponsive under memory pressure and there is
only

kernel: [2032243.696888] qlge 0000:8b:00.1 ql1: Could not get a page chunk, i=8, clean_idx =200 .
kernel: [2032243.710725] swapper/7: page allocation failure: order:1, mode:0x1084120(GFP_ATOMIC|__GFP_COLD|__GFP_COMP)

without an additional information for debugging.  It would be great to see
the state of the page allocator at the moment.

Link: http://lkml.kernel.org/r/20180907114334.7088-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:26:33 -07:00
Johannes Weiner eb414681d5 psi: pressure stall information for CPU, memory, and IO
When systems are overcommitted and resources become contended, it's hard
to tell exactly the impact this has on workload productivity, or how close
the system is to lockups and OOM kills.  In particular, when machines work
multiple jobs concurrently, the impact of overcommit in terms of latency
and throughput on the individual job can be enormous.

In order to maximize hardware utilization without sacrificing individual
job health or risk complete machine lockups, this patch implements a way
to quantify resource pressure in the system.

A kernel built with CONFIG_PSI=y creates files in /proc/pressure/ that
expose the percentage of time the system is stalled on CPU, memory, or IO,
respectively.  Stall states are aggregate versions of the per-task delay
accounting delays:

       cpu: some tasks are runnable but not executing on a CPU
       memory: tasks are reclaiming, or waiting for swapin or thrashing cache
       io: tasks are waiting for io completions

These percentages of walltime can be thought of as pressure percentages,
and they give a general sense of system health and productivity loss
incurred by resource overcommit.  They can also indicate when the system
is approaching lockup scenarios and OOMs.

To do this, psi keeps track of the task states associated with each CPU
and samples the time they spend in stall states.  Every 2 seconds, the
samples are averaged across CPUs - weighted by the CPUs' non-idle time to
eliminate artifacts from unused CPUs - and translated into percentages of
walltime.  A running average of those percentages is maintained over 10s,
1m, and 5m periods (similar to the loadaverage).

[hannes@cmpxchg.org: doc fixlet, per Randy]
  Link: http://lkml.kernel.org/r/20180828205625.GA14030@cmpxchg.org
[hannes@cmpxchg.org: code optimization]
  Link: http://lkml.kernel.org/r/20180907175015.GA8479@cmpxchg.org
[hannes@cmpxchg.org: rename psi_clock() to psi_update_work(), per Peter]
  Link: http://lkml.kernel.org/r/20180907145404.GB11088@cmpxchg.org
[hannes@cmpxchg.org: fix build]
  Link: http://lkml.kernel.org/r/20180913014222.GA2370@cmpxchg.org
Link: http://lkml.kernel.org/r/20180828172258.3185-9-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Daniel Drake <drake@endlessm.com>
Tested-by: Suren Baghdasaryan <surenb@google.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <jweiner@fb.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Enderborg <peter.enderborg@sony.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:26:32 -07:00
Vlastimil Babka b29940c1ab mm: rename and change semantics of nr_indirectly_reclaimable_bytes
The vmstat counter NR_INDIRECTLY_RECLAIMABLE_BYTES was introduced by
commit eb59254608 ("mm: introduce NR_INDIRECTLY_RECLAIMABLE_BYTES") with
the goal of accounting objects that can be reclaimed, but cannot be
allocated via a SLAB_RECLAIM_ACCOUNT cache.  This is now possible via
kmalloc() with __GFP_RECLAIMABLE flag, and the dcache external names user
is converted.

The counter is however still useful for accounting direct page allocations
(i.e.  not slab) with a shrinker, such as the ION page pool.  So keep it,
and:

- change granularity to pages to be more like other counters; sub-page
  allocations should be able to use kmalloc
- rename the counter to NR_KERNEL_MISC_RECLAIMABLE
- expose the counter again in vmstat as "nr_kernel_misc_reclaimable"; we can
  again remove the check for not printing "hidden" counters

Link: http://lkml.kernel.org/r/20180731090649.16028-5-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:26:32 -07:00
Oscar Salvador 7b0e0c0e35 mm/page_alloc.c: clean up check_for_memory()
check_for_memory() looks a bit confusing.  First of all, we have this:

if (N_MEMORY == N_NORMAL_MEMORY)
	return;

Checking the ENUM declaration, looks like N_MEMORY canot be equal to
N_NORMAL_MEMORY.

I could not find where N_MEMORY is set to N_NORMAL_MEMORY, or the other
way around either, so unless I am missing something, this condition will
never evaluate to true.  It makes sense to get rid of it.

Moving forward, the operations within the loop look a bit confusing as
well.

We set N_HIGH_MEMORY unconditionally, and then we set N_NORMAL_MEMORY in
case we have CONFIG_HIGHMEM (N_NORMAL_MEMORY != N_HIGH_MEMORY) and zone <=
ZONE_NORMAL.  (N_HIGH_MEMORY falls back to N_NORMAL_MEMORY on
!CONFIG_HIGHMEM systems, and that is why we can just go ahead and set
N_HIGH_MEMORY unconditionally)

Although this works, it is a bit subtle.

I think that this could be easier to follow:

First, we should only set N_HIGH_MEMORY in case we have CONFIG_HIGHMEM.
And then we should set N_NORMAL_MEMORY in case zone <= ZONE_NORMAL,
without further checking whether we have CONFIG_HIGHMEM or not.

Link: http://lkml.kernel.org/r/20180828210158.4617-1-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michael Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:25:19 -07:00
Michal Hocko 15f570bf3d mm,page_alloc: PF_WQ_WORKER threads must sleep at should_reclaim_retry()
Tetsuo Handa has reported that it is possible to bypass the short sleep
for PF_WQ_WORKER threads which was introduced by commit 373ccbe592
("mm, vmstat: allow WQ concurrency to discover memory reclaim doesn't make
any progress") and lock up the system if OOM.

The primary reason is that WQ_MEM_RECLAIM WQs are not guaranteed to run
even when they have a rescuer available.  Those workers might be essential
for reclaim to make a forward progress, however.  If we are too unlucky
all the allocations requests can get stuck waiting for a WQ_MEM_RECLAIM
work item and the system is essentially stuck in an OOM condition without
much hope to move on.  Tetsuo has seen the reclaim stuck on
drain_local_pages_wq or xlog_cil_push_work (xfs).  There might be others.

Since should_reclaim_retry() should be a natural reschedule point,
let's do the short sleep for PF_WQ_WORKER threads unconditionally in
order to guarantee that other pending work items are started.  This
will workaround this problem and it is less fragile than hunting down
when the sleep is missed.  Having a single sleeping point is more
robust.

[akpm@linux-foundation.org: reflow comment to 80 cols to save a couple of lines]
Link: http://lkml.kernel.org/r/20180827135101.15700-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Debugged-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:25:19 -07:00
Srikar Dronamraju e054637597 mm, sched/numa: Remove remaining traces of NUMA rate-limiting
Remove the leftover pglist_data::numabalancing_migrate_lock and its
initialization, we stopped using this lock with:

  efaffc5e40 ("mm, sched/numa: Remove rate-limiting of automatic NUMA balancing migration")

[ mingo: Rewrote the changelog. ]

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1538824999-31230-1-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-10-09 08:30:51 +02:00
Mel Gorman efaffc5e40 mm, sched/numa: Remove rate-limiting of automatic NUMA balancing migration
Rate limiting of page migrations due to automatic NUMA balancing was
introduced to mitigate the worst-case scenario of migrating at high
frequency due to false sharing or slowly ping-ponging between nodes.
Since then, a lot of effort was spent on correctly identifying these
pages and avoiding unnecessary migrations and the safety net may no longer
be required.

Jirka Hladky reported a regression in 4.17 due to a scheduler patch that
avoids spreading STREAM tasks wide prematurely. However, once the task
was properly placed, it delayed migrating the memory due to rate limiting.
Increasing the limit fixed the problem for him.

Currently, the limit is hard-coded and does not account for the real
capabilities of the hardware. Even if an estimate was attempted, it would
not properly account for the number of memory controllers and it could
not account for the amount of bandwidth used for normal accesses. Rather
than fudging, this patch simply eliminates the rate limiting.

However, Jirka reports that a STREAM configuration using multiple
processes achieved similar performance to 4.16. In local tests, this patch
improved performance of STREAM relative to the baseline but it is somewhat
machine-dependent. Most workloads show little or not performance difference
implying that there is not a heavily reliance on the throttling mechanism
and it is safe to remove.

STREAM on 2-socket machine
                         4.19.0-rc5             4.19.0-rc5
                         numab-v1r1       noratelimit-v1r1
MB/sec copy     43298.52 (   0.00%)    44673.38 (   3.18%)
MB/sec scale    30115.06 (   0.00%)    31293.06 (   3.91%)
MB/sec add      32825.12 (   0.00%)    34883.62 (   6.27%)
MB/sec triad    32549.52 (   0.00%)    34906.60 (   7.24%

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jirka Hladky <jhladky@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20181001100525.29789-2-mgorman@techsingularity.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-10-02 11:31:14 +02:00
Aneesh Kumar K.V 464c7ffbcb mm/hugetlb: filter out hugetlb pages if HUGEPAGE migration is not supported.
When scanning for movable pages, filter out Hugetlb pages if hugepage
migration is not supported.  Without this we hit infinte loop in
__offline_pages() where we do

	pfn = scan_movable_pages(start_pfn, end_pfn);
	if (pfn) { /* We have movable pages */
		ret = do_migrate_range(pfn, end_pfn);
		goto repeat;
	}

Fix this by checking hugepage_migration_supported both in
has_unmovable_pages which is the primary backoff mechanism for page
offlining and for consistency reasons also into scan_movable_pages
because it doesn't make any sense to return a pfn to non-migrateable
huge page.

This issue was revealed by, but not caused by 72b39cfc4d ("mm,
memory_hotplug: do not fail offlining too early").

Link: http://lkml.kernel.org/r/20180824063314.21981-1-aneesh.kumar@linux.ibm.com
Fixes: 72b39cfc4d ("mm, memory_hotplug: do not fail offlining too early")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reported-by: Haren Myneni <haren@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-09-04 16:45:02 -07:00
Mukesh Ojha 13ba17bee1 notifier: Remove notifier header file wherever not used
The conversion of the hotplug notifiers to a state machine left the
notifier.h includes around in some places. Remove them.

Signed-off-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1535114033-4605-1-git-send-email-mojha@codeaurora.org
2018-08-30 12:56:40 +02:00
Naoya Horiguchi d4ae9916ea mm: soft-offline: close the race against page allocation
A process can be killed with SIGBUS(BUS_MCEERR_AR) when it tries to
allocate a page that was just freed on the way of soft-offline.  This is
undesirable because soft-offline (which is about corrected error) is
less aggressive than hard-offline (which is about uncorrected error),
and we can make soft-offline fail and keep using the page for good
reason like "system is busy."

Two main changes of this patch are:

- setting migrate type of the target page to MIGRATE_ISOLATE. As done
  in free_unref_page_commit(), this makes kernel bypass pcplist when
  freeing the page. So we can assume that the page is in freelist just
  after put_page() returns,

- setting PG_hwpoison on free page under zone->lock which protects
  freelists, so this allows us to avoid setting PG_hwpoison on a page
  that is decided to be allocated soon.

[akpm@linux-foundation.org: tweak set_hwpoison_free_buddy_page() comment]
Link: http://lkml.kernel.org/r/1531452366-11661-3-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Xishi Qiu <xishi.qiuxishi@alibaba-inc.com>
Tested-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <zy.zhengyi@alibaba-inc.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-23 18:48:43 -07:00
Oscar Salvador 03e85f9d5f mm/page_alloc: Introduce free_area_init_core_hotplug
Currently, whenever a new node is created/re-used from the memhotplug
path, we call free_area_init_node()->free_area_init_core().  But there is
some code that we do not really need to run when we are coming from such
path.

free_area_init_core() performs the following actions:

1) Initializes pgdat internals, such as spinlock, waitqueues and more.
2) Account # nr_all_pages and # nr_kernel_pages. These values are used later on
   when creating hash tables.
3) Account number of managed_pages per zone, substracting dma_reserved and
   memmap pages.
4) Initializes some fields of the zone structure data
5) Calls init_currently_empty_zone to initialize all the freelists
6) Calls memmap_init to initialize all pages belonging to certain zone

When called from memhotplug path, free_area_init_core() only performs
actions #1 and #4.

Action #2 is pointless as the zones do not have any pages since either the
node was freed, or we are re-using it, eitherway all zones belonging to
this node should have 0 pages.  For the same reason, action #3 results
always in manages_pages being 0.

Action #5 and #6 are performed later on when onlining the pages:
 online_pages()->move_pfn_range_to_zone()->init_currently_empty_zone()
 online_pages()->move_pfn_range_to_zone()->memmap_init_zone()

This patch does two things:

First, moves the node/zone initializtion to their own function, so it
allows us to create a small version of free_area_init_core, where we only
perform:

1) Initialization of pgdat internals, such as spinlock, waitqueues and more
4) Initialization of some fields of the zone structure data

These two functions are: pgdat_init_internals() and zone_init_internals().

The second thing this patch does, is to introduce
free_area_init_core_hotplug(), the memhotplug version of
free_area_init_core():

Currently, we call free_area_init_node() from the memhotplug path.  In
there, we set some pgdat's fields, and call calculate_node_totalpages().
calculate_node_totalpages() calculates the # of pages the node has.

Since the node is either new, or we are re-using it, the zones belonging
to this node should not have any pages, so there is no point to calculate
this now.

Actually, we re-set these values to 0 later on with the calls to:

reset_node_managed_pages()
reset_node_present_pages()

The # of pages per node and the # of pages per zone will be calculated when
onlining the pages:

online_pages()->move_pfn_range()->move_pfn_range_to_zone()->resize_zone_range()
online_pages()->move_pfn_range()->move_pfn_range_to_zone()->resize_pgdat_range()

Also, since free_area_init_core/free_area_init_node will now only get called during early init, let us replace
__paginginit with __init, so their code gets freed up.

[osalvador@techadventures.net: fix section usage]
  Link: http://lkml.kernel.org/r/20180731101752.GA473@techadventures.net
[osalvador@suse.de: v6]
  Link: http://lkml.kernel.org/r/20180801122348.21588-6-osalvador@techadventures.net
Link: http://lkml.kernel.org/r/20180730101757.28058-5-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:45 -07:00
Oscar Salvador 0188dc98ad mm/page_alloc: inline function to handle CONFIG_DEFERRED_STRUCT_PAGE_INIT
Let us move the code between CONFIG_DEFERRED_STRUCT_PAGE_INIT to an inline
function.  Not having an ifdef in the function makes the code more
readable.

Link: http://lkml.kernel.org/r/20180730101757.28058-4-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:45 -07:00
Pavel Tatashin 7cc2a9596d mm: remove __paginginit
__paginginit is the same thing as __meminit except for platforms without
sparsemem, there it is defined as __init.

Remove __paginginit and use __meminit.  Use __ref in one single function
that merges __meminit and __init sections: setup_usemap().

Link: http://lkml.kernel.org/r/20180801122348.21588-4-osalvador@techadventures.net
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:45 -07:00
Pavel Tatashin c1093b746c mm: access zone->node via zone_to_nid() and zone_set_nid()
zone->node is configured only when CONFIG_NUMA=y, so it is a good idea to
have inline functions to access this field in order to avoid ifdef's in c
files.

Link: http://lkml.kernel.org/r/20180730101757.28058-3-osalvador@techadventures.net
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:45 -07:00
Oscar Salvador ace1db3976 mm/page_alloc.c: move ifdefery out of free_area_init_core
Patch series "Refactor free_area_init_core and add
free_area_init_core_hotplug", v6.

This patchset does three things:

 1) Clean up/refactor free_area_init_core/free_area_init_node
    by moving the ifdefery out of the functions.
 2) Move the pgdat/zone initialization in free_area_init_core to its
    own function.
 3) Introduce free_area_init_core_hotplug, a small subset of
    free_area_init_core, which is only called from memhotlug code path. In this
    way, we have:

    free_area_init_core: called during early initialization
    free_area_init_core_hotplug: called whenever a new node is allocated/re-used (memhotplug path)

This patch (of 5):

Moving the #ifdefs out of the function makes it easier to follow.

Link: http://lkml.kernel.org/r/20180730101757.28058-2-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:45 -07:00
Aaron Lu d8a759b570 mm, page_alloc: double zone's batchsize
To improve page allocator's performance for order-0 pages, each CPU has
a Per-CPU-Pageset(PCP) per zone.  Whenever an order-0 page is needed,
PCP will be checked first before asking pages from Buddy.  When PCP is
used up, a batch of pages will be fetched from Buddy to improve
performance and the size of batch can affect performance.

zone's batch size gets doubled last time by commit ba56e91c9401("mm:
page_alloc: increase size of per-cpu-pages") over ten years ago.  Since
then, CPU has envolved a lot and CPU's cache sizes also increased.

Dave Hansen is concerned the current batch size doesn't fit well with
modern hardware and suggested me to do two things: first, use a page
allocator intensive benchmark, e.g.  will-it-scale/page_fault1 to find
out how performance changes with different batch sizes on various
machines and then choose a new default batch size; second, see how this
new batch size work with other workloads.

In the first test, we saw performance gains on high-core-count systems
and little to no effect on older systems with more modest core counts.
In this phase's test data, two candidates: 63 and 127 are chosen.

In the second step, ebizzy, oltp, kbuild, pigz, netperf, vm-scalability
and more will-it-scale sub-tests are tested to see how these two
candidates work with these workloads and decides a new default according
to their results.

Most test results are flat.  will-it-scale/page_fault2 process mode has
10%-18% performance increase on 4-sockets Skylake and Broadwell.
vm-scalability/lru-file-mmap-read has 17%-47% performance increase for
4-sockets servers while for 2-sockets servers, it caused 3%-8% performance
drop.  Further analysis showed that, with a larger pcp->batch and thus
larger pcp->high(the relationship of pcp->high=6 * pcp->batch is
maintained in this patch), zone lock contention shifted to LRU add side
lock contention and that caused performance drop.  This performance drop
might be mitigated by others' work on optimizing LRU lock.

Another downside of increasing pcp->batch is, when PCP is used up and need
to fetch a batch of pages from Buddy, since batch is increased, that time
can be longer than before.  My understanding is, this doesn't affect
slowpath where direct reclaim and compaction dominates.  For fastpath,
throughput is a win(according to will-it-scale/page_fault1) but worst
latency can be larger now.

Overall, I think double the batch size from 31 to 63 is relatively safe
and provide good performance boost for high-core-count systems.

The two phase's test results are listed below(all tests are done with THP
disabled).

Phase one(will-it-scale/page_fault1) test results:

Skylake-EX: increased batch size has a good effect on zone->lock
contention, though LRU contention will rise at the same time and
limited the final performance increase.

batch   score     change   zone_contention   lru_contention   total_contention
 31   15345900    +0.00%       64%                 8%           72%
 53   17903847   +16.67%       32%                38%           70%
 63   17992886   +17.25%       24%                45%           69%
 73   18022825   +17.44%       10%                61%           71%
119   18023401   +17.45%        4%                66%           70%
127   18029012   +17.48%        3%                66%           69%
137   18036075   +17.53%        4%                66%           70%
165   18035964   +17.53%        2%                67%           69%
188   18101105   +17.95%        2%                67%           69%
223   18130951   +18.15%        2%                67%           69%
255   18118898   +18.07%        2%                67%           69%
267   18101559   +17.96%        2%                67%           69%
299   18160468   +18.34%        2%                68%           70%
320   18139845   +18.21%        2%                67%           69%
393   18160869   +18.34%        2%                68%           70%
424   18170999   +18.41%        2%                68%           70%
458   18144868   +18.24%        2%                68%           70%
467   18142366   +18.22%        2%                68%           70%
498   18154549   +18.30%        1%                68%           69%
511   18134525   +18.17%        1%                69%           70%

Broadwell-EX: similar pattern as Skylake-EX.

batch   score     change   zone_contention   lru_contention   total_contention
 31   16703983    +0.00%       67%                 7%           74%
 53   18195393    +8.93%       43%                28%           71%
 63   18288885    +9.49%       38%                33%           71%
 73   18344329    +9.82%       35%                37%           72%
119   18535529   +10.96%       24%                46%           70%
127   18513596   +10.83%       23%                48%           71%
137   18514327   +10.84%       23%                48%           71%
165   18511840   +10.82%       22%                49%           71%
188   18593478   +11.31%       17%                53%           70%
223   18601667   +11.36%       17%                52%           69%
255   18774825   +12.40%       12%                58%           70%
267   18754781   +12.28%        9%                60%           69%
299   18892265   +13.10%        7%                63%           70%
320   18873812   +12.99%        8%                62%           70%
393   18891174   +13.09%        6%                64%           70%
424   18975108   +13.60%        6%                64%           70%
458   18932364   +13.34%        8%                62%           70%
467   18960891   +13.51%        5%                65%           70%
498   18944526   +13.41%        5%                64%           69%
511   18960839   +13.51%        5%                64%           69%

Skylake-EP: although increased batch reduced zone->lock contention, but
the effect is not as good as EX: zone->lock contention is still as high as
20% with a very high batch value instead of 1% on Skylake-EX or 5% on
Broadwell-EX.  Also, total_contention actually decreased with a higher
batch but that doesn't translate to performance increase.

batch   score    change   zone_contention   lru_contention   total_contention
 31   9554867    +0.00%       66%                 3%           69%
 53   9855486    +3.15%       63%                 3%           66%
 63   9980145    +4.45%       62%                 4%           66%
 73   10092774   +5.63%       62%                 5%           67%
119   10310061   +7.90%       45%                19%           64%
127   10342019   +8.24%       42%                19%           61%
137   10358182   +8.41%       42%                21%           63%
165   10397060   +8.81%       37%                24%           61%
188   10341808   +8.24%       34%                26%           60%
223   10349135   +8.31%       31%                27%           58%
255   10327189   +8.08%       28%                29%           57%
267   10344204   +8.26%       27%                29%           56%
299   10325043   +8.06%       25%                30%           55%
320   10310325   +7.91%       25%                31%           56%
393   10293274   +7.73%       21%                31%           52%
424   10311099   +7.91%       21%                32%           53%
458   10321375   +8.02%       21%                32%           53%
467   10303881   +7.84%       21%                32%           53%
498   10332462   +8.14%       20%                33%           53%
511   10325016   +8.06%       20%                32%           52%

Broadwell-EP: zone->lock and lru lock had an agreement to make sure
performance doesn't increase and they successfully managed to keep total
contention at 70%.

batch   score    change   zone_contention   lru_contention   total_contention
 31   10121178   +0.00%       19%                50%           69%
 53   10142366   +0.21%        6%                63%           69%
 63   10117984   -0.03%       11%                58%           69%
 73   10123330   +0.02%        7%                63%           70%
119   10108791   -0.12%        2%                67%           69%
127   10166074   +0.44%        3%                66%           69%
137   10141574   +0.20%        3%                66%           69%
165   10154499   +0.33%        2%                68%           70%
188   10124921   +0.04%        2%                67%           69%
223   10137399   +0.16%        2%                67%           69%
255   10143289   +0.22%        0%                68%           68%
267   10123535   +0.02%        1%                68%           69%
299   10140952   +0.20%        0%                68%           68%
320   10163170   +0.41%        0%                68%           68%
393   10000633   -1.19%        0%                69%           69%
424   10087998   -0.33%        0%                69%           69%
458   10187116   +0.65%        0%                69%           69%
467   10146790   +0.25%        0%                69%           69%
498   10197958   +0.76%        0%                69%           69%
511   10152326   +0.31%        0%                69%           69%

Haswell-EP: similar to Broadwell-EP.

batch   score   change   zone_contention   lru_contention   total_contention
 31   10442205   +0.00%       14%                48%           62%
 53   10442255   +0.00%        5%                57%           62%
 63   10452059   +0.09%        6%                57%           63%
 73   10482349   +0.38%        5%                59%           64%
119   10454644   +0.12%        3%                60%           63%
127   10431514   -0.10%        3%                59%           62%
137   10423785   -0.18%        3%                60%           63%
165   10481216   +0.37%        2%                61%           63%
188   10448755   +0.06%        2%                61%           63%
223   10467144   +0.24%        2%                61%           63%
255   10480215   +0.36%        2%                61%           63%
267   10484279   +0.40%        2%                61%           63%
299   10466450   +0.23%        2%                61%           63%
320   10452578   +0.10%        2%                61%           63%
393   10499678   +0.55%        1%                62%           63%
424   10481454   +0.38%        1%                62%           63%
458   10473562   +0.30%        1%                62%           63%
467   10484269   +0.40%        0%                62%           62%
498   10505599   +0.61%        0%                62%           62%
511   10483395   +0.39%        0%                62%           62%

Westmere-EP: contention is pretty small so not interesting.  Note too high
a batch value could hurt performance.

batch   score   change   zone_contention   lru_contention   total_contention
 31   4831523   +0.00%        2%                 3%            5%
 53   4834086   +0.05%        2%                 4%            6%
 63   4834262   +0.06%        2%                 3%            5%
 73   4832851   +0.03%        2%                 4%            6%
119   4830534   -0.02%        1%                 3%            4%
127   4827461   -0.08%        1%                 4%            5%
137   4827459   -0.08%        1%                 3%            4%
165   4820534   -0.23%        0%                 4%            4%
188   4817947   -0.28%        0%                 3%            3%
223   4809671   -0.45%        0%                 3%            3%
255   4802463   -0.60%        0%                 4%            4%
267   4801634   -0.62%        0%                 3%            3%
299   4798047   -0.69%        0%                 3%            3%
320   4793084   -0.80%        0%                 3%            3%
393   4785877   -0.94%        0%                 3%            3%
424   4782911   -1.01%        0%                 3%            3%
458   4779346   -1.08%        0%                 3%            3%
467   4780306   -1.06%        0%                 3%            3%
498   4780589   -1.05%        0%                 3%            3%
511   4773724   -1.20%        0%                 3%            3%

Skylake-Desktop: similar to Westmere-EP, nothing interesting.

batch   score   change   zone_contention   lru_contention   total_contention
 31   3906608   +0.00%        2%                 3%            5%
 53   3940164   +0.86%        2%                 3%            5%
 63   3937289   +0.79%        2%                 3%            5%
 73   3940201   +0.86%        2%                 3%            5%
119   3933240   +0.68%        2%                 3%            5%
127   3930514   +0.61%        2%                 4%            6%
137   3938639   +0.82%        0%                 3%            3%
165   3908755   +0.05%        0%                 3%            3%
188   3905621   -0.03%        0%                 3%            3%
223   3903015   -0.09%        0%                 4%            4%
255   3889480   -0.44%        0%                 3%            3%
267   3891669   -0.38%        0%                 4%            4%
299   3898728   -0.20%        0%                 4%            4%
320   3894547   -0.31%        0%                 4%            4%
393   3875137   -0.81%        0%                 4%            4%
424   3874521   -0.82%        0%                 3%            3%
458   3880432   -0.67%        0%                 4%            4%
467   3888715   -0.46%        0%                 3%            3%
498   3888633   -0.46%        0%                 4%            4%
511   3875305   -0.80%        0%                 5%            5%

Haswell-Desktop: zone->lock is pretty low as other desktops, though lru
contention is higher than other desktops.

batch   score   change   zone_contention   lru_contention   total_contention
 31   3511158   +0.00%        2%                 5%            7%
 53   3555445   +1.26%        2%                 6%            8%
 63   3561082   +1.42%        2%                 6%            8%
 73   3547218   +1.03%        2%                 6%            8%
119   3571319   +1.71%        1%                 7%            8%
127   3549375   +1.09%        0%                 6%            6%
137   3560233   +1.40%        0%                 6%            6%
165   3555176   +1.25%        2%                 6%            8%
188   3551501   +1.15%        0%                 8%            8%
223   3531462   +0.58%        0%                 7%            7%
255   3570400   +1.69%        0%                 7%            7%
267   3532235   +0.60%        1%                 8%            9%
299   3562326   +1.46%        0%                 6%            6%
320   3553569   +1.21%        0%                 8%            8%
393   3539519   +0.81%        0%                 7%            7%
424   3549271   +1.09%        0%                 8%            8%
458   3528885   +0.50%        0%                 8%            8%
467   3526554   +0.44%        0%                 7%            7%
498   3525302   +0.40%        0%                 9%            9%
511   3527556   +0.47%        0%                 8%            8%

Sandybridge-Desktop: the 0% contention isn't accurate but caused by
dropped fractional part. Since multiple contention path's contentions
are all under 1% here, with some arithmetic operations like add, the
final deviation could be as large as 3%.

batch   score   change   zone_contention   lru_contention   total_contention
 31   1744495   +0.00%        0%                 0%            0%
 53   1755341   +0.62%        0%                 0%            0%
 63   1758469   +0.80%        0%                 0%            0%
 73   1759626   +0.87%        0%                 0%            0%
119   1770417   +1.49%        0%                 0%            0%
127   1768252   +1.36%        0%                 0%            0%
137   1767848   +1.34%        0%                 0%            0%
165   1765088   +1.18%        0%                 0%            0%
188   1766918   +1.29%        0%                 0%            0%
223   1767866   +1.34%        0%                 0%            0%
255   1768074   +1.35%        0%                 0%            0%
267   1763187   +1.07%        0%                 0%            0%
299   1765620   +1.21%        0%                 0%            0%
320   1767603   +1.32%        0%                 0%            0%
393   1764612   +1.15%        0%                 0%            0%
424   1758476   +0.80%        0%                 0%            0%
458   1758593   +0.81%        0%                 0%            0%
467   1757915   +0.77%        0%                 0%            0%
498   1753363   +0.51%        0%                 0%            0%
511   1755548   +0.63%        0%                 0%            0%

Phase two test results:
Note: all percent change is against base(batch=31).

ebizzy.throughput (higer is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    2410037±7%     2600451±2% +7.9%     2602878 +8.0%
lkp-bdw-ex1     1493328        1489243    -0.3%     1492145 -0.1%
lkp-skl-2sp2    1329674        1345891    +1.2%     1351056 +1.6%
lkp-bdw-ep2      711511         711511     0.0%      710708 -0.1%
lkp-wsm-ep2       75750          75528    -0.3%       75441 -0.4%
lkp-skl-d01      264126         262791    -0.5%      264113 +0.0%
lkp-hsw-d01      176601         176328    -0.2%      176368 -0.1%
lkp-sb02          98937          98937    +0.0%       99030 +0.1%

kbuild.buildtime (less is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1     107.00        107.67  +0.6%        107.11  +0.1%
lkp-bdw-ex1       97.33         97.33  +0.0%         97.42  +0.1%
lkp-skl-2sp2     180.00        179.83  -0.1%        179.83  -0.1%
lkp-bdw-ep2      178.17        179.17  +0.6%        177.50  -0.4%
lkp-wsm-ep2      737.00        738.00  +0.1%        738.00  +0.1%
lkp-skl-d01      642.00        653.00  +1.7%        653.00  +1.7%
lkp-hsw-d01     1310.00       1316.00  +0.5%       1311.00  +0.1%

netperf/TCP_STREAM.Throughput_total_Mbps (higher is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1     948790        947144  -0.2%        948333 -0.0%
lkp-bdw-ex1      904224        904366  +0.0%        904926 +0.1%
lkp-skl-2sp2     239731        239607  -0.1%        239565 -0.1%
lk-bdw-ep2       365764        365933  +0.0%        365951 +0.1%
lkp-wsm-ep2       93736         93803  +0.1%         93808 +0.1%
lkp-skl-d01       77314         77303  -0.0%         77375 +0.1%
lkp-hsw-d01       58617         60387  +3.0%         60208 +2.7%
lkp-sb02          29990         30137  +0.5%         30103 +0.4%

oltp.transactions (higer is better)

machine         batch=31      batch=63             batch=127
lkp-bdw-ex1      9073276       9100377     +0.3%    9036344     -0.4%
lkp-skl-2sp2     8898717       8852054     -0.5%    8894459     -0.0%
lkp-bdw-ep2     13426155      13384654     -0.3%   13333637     -0.7%
lkp-hsw-ep2     13146314      13232784     +0.7%   13193163     +0.4%
lkp-wsm-ep2      5035355       5019348     -0.3%    5033418     -0.0%
lkp-skl-d01       418485       4413339     -0.1%    4419039     +0.0%
lkp-hsw-d01      3517817±5%    3396120±3%  -3.5%    3455138±3%  -1.8%

pigz.throughput (higer is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    1.513e+08     1.507e+08 -0.4%      1.511e+08 -0.2%
lkp-bdw-ex1     2.060e+08     2.052e+08 -0.4%      2.044e+08 -0.8%
lkp-skl-2sp2    8.836e+08     8.845e+08 +0.1%      8.836e+08 -0.0%
lkp-bdw-ep2     8.275e+08     8.464e+08 +2.3%      8.330e+08 +0.7%
lkp-wsm-ep2     2.224e+08     2.221e+08 -0.2%      2.218e+08 -0.3%
lkp-skl-d01     1.177e+08     1.177e+08 -0.0%      1.176e+08 -0.1%
lkp-hsw-d01     1.154e+08     1.154e+08 +0.1%      1.154e+08 -0.0%
lkp-sb02        0.633e+08     0.633e+08 +0.1%      0.633e+08 +0.0%

will-it-scale.malloc1.processes (higher is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1      620181       620484 +0.0%         620240 +0.0%
lkp-bdw-ex1      1403610      1401201 -0.2%        1417900 +1.0%
lkp-skl-2sp2     1288097      1284145 -0.3%        1283907 -0.3%
lkp-bdw-ep2      1427879      1427675 -0.0%        1428266 +0.0%
lkp-hsw-ep2      1362546      1353965 -0.6%        1354759 -0.6%
lkp-wsm-ep2      2099657      2107576 +0.4%        2100226 +0.0%
lkp-skl-d01      1476835      1476358 -0.0%        1474487 -0.2%
lkp-hsw-d01      1308810      1303429 -0.4%        1301299 -0.6%
lkp-sb02          589286       589284 -0.0%         588101 -0.2%

will-it-scale.malloc1.threads (higher is better)
machine         batch=31      batch=63             batch=127
lkp-skl-4sp1     21289         21125     -0.8%      21241     -0.2%
lkp-bdw-ex1      28114         28089     -0.1%      28007     -0.4%
lkp-skl-2sp2     91866         91946     +0.1%      92723     +0.9%
lkp-bdw-ep2      37637         37501     -0.4%      37317     -0.9%
lkp-hsw-ep2      43673         43590     -0.2%      43754     +0.2%
lkp-wsm-ep2      28577         28298     -1.0%      28545     -0.1%
lkp-skl-d01     175277        173343     -1.1%     173082     -1.3%
lkp-hsw-d01     130303        129566     -0.6%     129250     -0.8%
lkp-sb02        113742±3%     116911     +2.8%     116417±3%  +2.4%

will-it-scale.malloc2.processes (higer is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    1.206e+09     1.206e+09 -0.0%      1.206e+09 +0.0%
lkp-bdw-ex1     1.319e+09     1.319e+09 -0.0%      1.319e+09 +0.0%
lkp-skl-2sp2    8.000e+08     8.021e+08 +0.3%      7.995e+08 -0.1%
lkp-bdw-ep2     6.582e+08     6.634e+08 +0.8%      6.513e+08 -1.1%
lkp-hsw-ep2     6.671e+08     6.669e+08 -0.0%      6.665e+08 -0.1%
lkp-wsm-ep2     1.805e+08     1.806e+08 +0.0%      1.804e+08 -0.1%
lkp-skl-d01     1.611e+08     1.611e+08 -0.0%      1.610e+08 -0.0%
lkp-hsw-d01     1.333e+08     1.332e+08 -0.0%      1.332e+08 -0.0%
lkp-sb02         82485104      82478206 -0.0%       82473546 -0.0%

will-it-scale.malloc2.threads (higer is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    1.574e+09     1.574e+09 -0.0%      1.574e+09 -0.0%
lkp-bdw-ex1     1.737e+09     1.737e+09 +0.0%      1.737e+09 -0.0%
lkp-skl-2sp2    9.161e+08     9.162e+08 +0.0%      9.181e+08 +0.2%
lkp-bdw-ep2     7.856e+08     8.015e+08 +2.0%      8.113e+08 +3.3%
lkp-hsw-ep2     6.908e+08     6.904e+08 -0.1%      6.907e+08 -0.0%
lkp-wsm-ep2     2.409e+08     2.409e+08 +0.0%      2.409e+08 -0.0%
lkp-skl-d01     1.199e+08     1.199e+08 -0.0%      1.199e+08 -0.0%
lkp-hsw-d01     1.029e+08     1.029e+08 -0.0%      1.029e+08 +0.0%
lkp-sb02         68081213      68061423 -0.0%       68076037 -0.0%

will-it-scale.page_fault2.processes (higer is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    14509125±4%   16472364 +13.5%       17123117 +18.0%
lkp-bdw-ex1     14736381      16196588  +9.9%       16364011 +11.0%
lkp-skl-2sp2     6354925       6435444  +1.3%        6436644  +1.3%
lkp-bdw-ep2      8749584       8834422  +1.0%        8827179  +0.9%
lkp-hsw-ep2      8762591       8845920  +1.0%        8825697  +0.7%
lkp-wsm-ep2      3036083       3030428  -0.2%        3021741  -0.5%
lkp-skl-d01      2307834       2304731  -0.1%        2286142  -0.9%
lkp-hsw-d01      1806237       1800786  -0.3%        1795943  -0.6%
lkp-sb02          842616        837844  -0.6%         833921  -1.0%

will-it-scale.page_fault2.threads

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1     1623294       1615132±2% -0.5%     1656777    +2.1%
lkp-bdw-ex1      1995714       2025948    +1.5%     2113753±3% +5.9%
lkp-skl-2sp2     2346708       2415591    +2.9%     2416919    +3.0%
lkp-bdw-ep2      2342564       2344882    +0.1%     2300206    -1.8%
lkp-hsw-ep2      1820658       1831681    +0.6%     1844057    +1.3%
lkp-wsm-ep2      1725482       1733774    +0.5%     1740517    +0.9%
lkp-skl-d01      1832833       1823628    -0.5%     1806489    -1.4%
lkp-hsw-d01      1427913       1427287    -0.0%     1420226    -0.5%
lkp-sb02          750626        748615    -0.3%      746621    -0.5%

will-it-scale.page_fault3.processes (higher is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    24382726      24400317 +0.1%       24668774 +1.2%
lkp-bdw-ex1     35399750      35683124 +0.8%       35829492 +1.2%
lkp-skl-2sp2    28136820      28068248 -0.2%       28147989 +0.0%
lkp-bdw-ep2     37269077      37459490 +0.5%       37373073 +0.3%
lkp-hsw-ep2     36224967      36114085 -0.3%       36104908 -0.3%
lkp-wsm-ep2     16820457      16911005 +0.5%       16968596 +0.9%
lkp-skl-d01      7721138       7725904 +0.1%        7756740 +0.5%
lkp-hsw-d01      7611979       7650928 +0.5%        7651323 +0.5%
lkp-sb02         3781546       3796502 +0.4%        3796827 +0.4%

will-it-scale.page_fault3.threads (higer is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1     1865820±3%   1900917±2%  +1.9%     1826245±4%  -2.1%
lkp-bdw-ex1      3094060      3148326     +1.8%     3150036     +1.8%
lkp-skl-2sp2     3952940      3953898     +0.0%     3989360     +0.9%
lkp-bdw-ep2      3420373±3%   3643964     +6.5%     3644910±5%  +6.6%
lkp-hsw-ep2      2609635±2%   2582310±3%  -1.0%     2780459     +6.5%
lkp-wsm-ep2      4395001      4417196     +0.5%     4432499     +0.9%
lkp-skl-d01      5363977      5400003     +0.7%     5411370     +0.9%
lkp-hsw-d01      5274131      5311294     +0.7%     5319359     +0.9%
lkp-sb02         2917314      2913004     -0.1%     2935286     +0.6%

will-it-scale.read1.processes (higer is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    73762279±14%  69322519±10% -6.0%    69349855±13%  -6.0% (result unstable)
lkp-bdw-ex1     1.701e+08     1.704e+08    +0.1%    1.705e+08     +0.2%
lkp-skl-2sp2    63111570      63113953     +0.0%    63836573      +1.1%
lkp-bdw-ep2     79247409      79424610     +0.2%    78012656      -1.6%
lkp-hsw-ep2     67677026      68308800     +0.9%    67539106      -0.2%
lkp-wsm-ep2     13339630      13939817     +4.5%    13766865      +3.2%
lkp-skl-d01     10969487      10972650     +0.0%    no data
lkp-hsw-d01     9857342±2%    10080592±2%  +2.3%    10131560      +2.8%
lkp-sb02        5189076        5197473     +0.2%    5163253       -0.5%

will-it-scale.read1.threads (higher is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    62468045±12%  73666726±7% +17.9%    79553123±12% +27.4% (result unstable)
lkp-bdw-ex1     1.62e+08      1.624e+08    +0.3%    1.614e+08     -0.3%
lkp-skl-2sp2    58319780      59181032     +1.5%    59821353      +2.6%
lkp-bdw-ep2     74057992      75698171     +2.2%    74990869      +1.3%
lkp-hsw-ep2     63672959      63639652     -0.1%    64387051      +1.1%
lkp-wsm-ep2     13489943      13526058     +0.3%    13259032      -1.7%
lkp-skl-d01     10297906      10338796     +0.4%    10407328      +1.1%
lkp-hsw-d01      9636721       9667376     +0.3%     9341147      -3.1%
lkp-sb02         4801938       4804496     +0.1%     4802290      +0.0%

will-it-scale.write1.processes (higer is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    1.111e+08     1.104e+08±2%  -0.7%   1.122e+08±2%  +1.0%
lkp-bdw-ex1     1.392e+08     1.399e+08     +0.5%   1.397e+08     +0.4%
lkp-skl-2sp2     59369233      58994841     -0.6%    58715168     -1.1%
lkp-bdw-ep2      61820979      CPU throttle          63593123     +2.9%
lkp-hsw-ep2      57897587      57435605     -0.8%    56347450     -2.7%
lkp-wsm-ep2       7814203       7918017±2%  +1.3%     7669068     -1.9%
lkp-skl-d01       8886557       8971422     +1.0%     8818366     -0.8%
lkp-hsw-d01       9171001±5%    9189915     +0.2%     9483909     +3.4%
lkp-sb02          4475406       4475294     -0.0%     4501756     +0.6%

will-it-scale.write1.threads (higer is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    1.058e+08     1.055e+08±2%  -0.2%   1.065e+08  +0.7%
lkp-bdw-ex1     1.316e+08     1.300e+08     -1.2%   1.308e+08  -0.6%
lkp-skl-2sp2     54492421      56086678     +2.9%    55975657  +2.7%
lkp-bdw-ep2      59360449      59003957     -0.6%    58101262  -2.1%
lkp-hsw-ep2      53346346±2%   52530876     -1.5%    52902487  -0.8%
lkp-wsm-ep2       7774006       7800092±2%  +0.3%     7558833  -2.8%
lkp-skl-d01       8346174       8235695     -1.3%     no data
lkp-hsw-d01       8636244       8655731     +0.2%     8658868  +0.3%
lkp-sb02          4181820       4204107     +0.5%     4182992  +0.0%

vm-scalability.anon-r-rand.throughput (higher is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    11933873±3%   12356544±2%  +3.5%   12188624     +2.1%
lkp-bdw-ex1      7114424±2%    7330949±2%  +3.0%    7392419     +3.9%
lkp-skl-2sp2     6773277±5%    6492332±8%  -4.1%    6543962     -3.4%
lkp-bdw-ep2      7133846±4%    7233508     +1.4%    7013518±3%  -1.7%
lkp-hsw-ep2      4576626       4527098     -1.1%    4551679     -0.5%
lkp-wsm-ep2      2583599       2592492     +0.3%    2588039     +0.2%
lkp-hsw-d01       998199±2%    1028311     +3.0%    1006460±2%  +0.8%
lkp-sb02          570572        567854     -0.5%     568449     -0.4%

vm-scalability.anon-r-rand-mt.throughput (higher is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1     1789419       1787830     -0.1%    1788208     -0.1%
lkp-bdw-ex1      3492595±2%    3554966±2%  +1.8%    3558835±3%  +1.9%
lkp-skl-2sp2     3856238±2%    3975403±4%  +3.1%    3994600     +3.6%
lkp-bdw-ep2      3726963±11%   3809292±6%  +2.2%    3871924±4%  +3.9%
lkp-hsw-ep2      2131760±3%    2033578±4%  -4.6%    2130727±6%  -0.0%
lkp-wsm-ep2      2369731       2368384     -0.1%    2370252     +0.0%
lkp-skl-d01      1207128       1206220     -0.1%    1205801     -0.1%
lkp-hsw-d01       964317        992329±2%  +2.9%     992099±2%  +2.9%
lkp-sb02          567137        567346     +0.0%     566144     -0.2%

vm-scalability.lru-file-mmap-read.throughput (higher is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1    19560469±6%   23018999     +17.7%   23418800     +19.7%
lkp-bdw-ex1     17769135±14%  26141676±3%  +47.1%   26284723±5%  +47.9%
lkp-skl-2sp2    14056512      13578884      -3.4%   13146214      -6.5%
lkp-bdw-ep2     15336542      14737654      -3.9%   14088159      -8.1%
lkp-hsw-ep2     16275498      15756296      -3.2%   15018090      -7.7%
lkp-wsm-ep2     11272160      11237231      -0.3%   11310047      +0.3%
lkp-skl-d01      7322119       7324569      +0.0%    7184148      -1.9%
lkp-hsw-d01      6449234       6404542      -0.7%    6356141      -1.4%
lkp-sb02         3517943       3520668      +0.1%    3527309      +0.3%

vm-scalability.lru-file-mmap-read-rand.throughput (higher is better)

machine         batch=31      batch=63             batch=127
lkp-skl-4sp1     1689052       1697553  +0.5%       1698726  +0.6%
lkp-bdw-ex1      1675246       1699764  +1.5%       1712226  +2.2%
lkp-skl-2sp2     1800533       1799749  -0.0%       1800581  +0.0%
lkp-bdw-ep2      1807422       1807758  +0.0%       1804932  -0.1%
lkp-hsw-ep2      1809807       1808781  -0.1%       1807811  -0.1%
lkp-wsm-ep2      1800198       1802434  +0.1%       1801236  +0.1%
lkp-skl-d01       696689        695537  -0.2%        694106  -0.4%
lkp-hsw-d01       698364        698666  +0.0%        696686  -0.2%
lkp-sb02          258939        258787  -0.1%        258199  -0.3%

Link: http://lkml.kernel.org/r/20180711055855.29072-1-aaron.lu@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17 16:20:32 -07:00
Michal Hocko 9ea9a68064 mm: drop VM_BUG_ON from __get_free_pages
There is no real reason to blow up just because the caller doesn't know
that __get_free_pages cannot return highmem pages.  Simply fix that up
silently.  Even if we have some confused users such a fixup will not be
harmful.

[akpm@linux-foundation.org: mask off __GFP_HIGHMEM]
Link: http://lkml.kernel.org/r/20180622162841.25114-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiankang Chen <chenjiankang1@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17 16:20:29 -07:00
Vlastimil Babka d6a24df006 mm, page_alloc: actually ignore mempolicies for high priority allocations
__alloc_pages_slowpath() has for a long time contained code to ignore
node restrictions from memory policies for high priority allocations.
The current code that resets the zonelist iterator however does
effectively nothing after commit 7810e6781e ("mm, page_alloc: do not
break __GFP_THISNODE by zonelist reset") removed a buggy zonelist reset.
Even before that commit, mempolicy restrictions were still not ignored,
as they are passed in ac->nodemask which is untouched by the code.

We can either remove the code, or make it work as intended.  Since
ac->nodemask can be set from task's mempolicy via alloc_pages_current()
and thus also alloc_pages(), it may indeed affect kernel allocations,
and it makes sense to ignore it to allow progress for high priority
allocations.

Thus, this patch resets ac->nodemask to NULL in such cases.  This
assumes all callers can handle it (i.e.  there are no guarantees as in
the case of __GFP_THISNODE) which seems to be the case.  The same
assumption is already present in check_retry_cpuset() for some time.

The expected effect is that high priority kernel allocations in the
context of userspace tasks (e.g.  OOM victims) restricted by mempolicies
will have higher chance to succeed if they are restricted to nodes with
depleted memory, while there are other nodes with free memory left.

It's not a new intention, but for the first time the code will match the
intention, AFAICS.  It was intended by commit 183f6371aa ("mm: ignore
mempolicies when using ALLOC_NO_WATERMARK") in v3.6 but I think it never
really worked, as mempolicy restriction was already encoded in nodemask,
not zonelist, at that time.

So originally that was for ALLOC_NO_WATERMARK only.  Then it was
adjusted by e46e7b77c9 ("mm, page_alloc: recalculate the preferred
zoneref if the context can ignore memory policies") and cd04ae1e2d
("mm, oom: do not rely on TIF_MEMDIE for memory reserves access") to the
current state.  So even GFP_ATOMIC would now ignore mempolicies after
the initial attempts fail - if the code worked as people thought it
does.

Link: http://lkml.kernel.org/r/20180612122624.8045-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17 16:20:28 -07:00
Pavel Tatashin 720e14ebec mm: skip invalid pages block at a time in zero_resv_unresv()
The role of zero_resv_unavail() is to make sure that every struct page
that is allocated but is not backed by memory that is accessible by
kernel is zeroed and not in some uninitialized state.

Since struct pages are allocated in blocks (2M pages in x86 case), we
can skip pageblock_nr_pages at a time, when the first one is found to be
invalid.

This optimization may help since now on x86 every hole in e820 maps is
marked as reserved in memblock, and thus will go through this function.

This function is called before sched_clock() is initialized, so I used
my x86 early boot clock patches to measure the performance improvement.

With 1T hole on i7-8700 currently we would take 0.606918s of boot time,
but with this optimization 0.001103s.

Link: http://lkml.kernel.org/r/20180615155733.1175-1-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17 16:20:28 -07:00
Linus Torvalds b018fc9800 Power management updates for 4.19-rc1
- Add a new framework for CPU idle time injection (Daniel Lezcano).
 
  - Add AVS support to the armada-37xx cpufreq driver (Gregory CLEMENT).
 
  - Add support for current CPU frequency reporting to the ACPI CPPC
    cpufreq driver (George Cherian).
 
  - Rework the cooling device registration in the imx6q/thermal
    driver (Bastian Stender).
 
  - Make the pcc-cpufreq driver refuse to work with dynamic
    scaling governors on systems with many CPUs to avoid
    scalability issues with it (Rafael Wysocki).
 
  - Fix the intel_pstate driver to report different maximum CPU
    frequencies on systems where they really are different and to
    ignore the turbo active ratio if hardware-managend P-states (HWP)
    are in use; make it use the match_string() helper (Xie Yisheng,
    Srinivas Pandruvada).
 
  - Fix a minor deferred probe issue in the qcom-kryo cpufreq
    driver (Niklas Cassel).
 
  - Add a tracepoint for the tracking of frequency limits changes
    (from Andriod) to the cpufreq core (Ruchi Kandoi).
 
  - Fix a circular lock dependency between CPU hotplug and sysfs
    locking in the cpufreq core reported by lockdep (Waiman Long).
 
  - Avoid excessive error reports on driver registration failures
    in the ARM cpuidle driver (Sudeep Holla).
 
  - Add a new device links flag to the driver core to make links go
    away automatically on supplier driver removal (Vivek Gautam).
 
  - Eliminate potential race condition between system-wide power
    management transitions and system shutdown (Pingfan Liu).
 
  - Add a quirk to save NVS memory on system suspend for the ASUS
    1025C laptop (Willy Tarreau).
 
  - Make more systems use suspend-to-idle (instead of ACPI S3) by
    default (Tristian Celestin).
 
  - Get rid of stack VLA usage in the low-level hibernation code on
    64-bit x86 (Kees Cook).
 
  - Fix error handling in the hibernation core and mark an expected
    fall-through switch in it (Chengguang Xu, Gustavo Silva).
 
  - Extend the generic power domains (genpd) framework to support
    attaching a device to a power domain by name (Ulf Hansson).
 
  - Fix device reference counting and user limits initialization in
    the devfreq core (Arvind Yadav, Matthias Kaehlcke).
 
  - Fix a few issues in the rk3399_dmc devfreq driver and improve its
    documentation (Enric Balletbo i Serra, Lin Huang, Nick Milner).
 
  - Drop a redundant error message from the exynos-ppmu devfreq driver
    (Markus Elfring).
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Merge tag 'pm-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "These add a new framework for CPU idle time injection, to be used by
  all of the idle injection code in the kernel in the future, fix some
  issues and add a number of relatively small extensions in multiple
  places.

  Specifics:

   - Add a new framework for CPU idle time injection (Daniel Lezcano).

   - Add AVS support to the armada-37xx cpufreq driver (Gregory
     CLEMENT).

   - Add support for current CPU frequency reporting to the ACPI CPPC
     cpufreq driver (George Cherian).

   - Rework the cooling device registration in the imx6q/thermal driver
     (Bastian Stender).

   - Make the pcc-cpufreq driver refuse to work with dynamic scaling
     governors on systems with many CPUs to avoid scalability issues
     with it (Rafael Wysocki).

   - Fix the intel_pstate driver to report different maximum CPU
     frequencies on systems where they really are different and to
     ignore the turbo active ratio if hardware-managend P-states (HWP)
     are in use; make it use the match_string() helper (Xie Yisheng,
     Srinivas Pandruvada).

   - Fix a minor deferred probe issue in the qcom-kryo cpufreq driver
     (Niklas Cassel).

   - Add a tracepoint for the tracking of frequency limits changes (from
     Andriod) to the cpufreq core (Ruchi Kandoi).

   - Fix a circular lock dependency between CPU hotplug and sysfs
     locking in the cpufreq core reported by lockdep (Waiman Long).

   - Avoid excessive error reports on driver registration failures in
     the ARM cpuidle driver (Sudeep Holla).

   - Add a new device links flag to the driver core to make links go
     away automatically on supplier driver removal (Vivek Gautam).

   - Eliminate potential race condition between system-wide power
     management transitions and system shutdown (Pingfan Liu).

   - Add a quirk to save NVS memory on system suspend for the ASUS 1025C
     laptop (Willy Tarreau).

   - Make more systems use suspend-to-idle (instead of ACPI S3) by
     default (Tristian Celestin).

   - Get rid of stack VLA usage in the low-level hibernation code on
     64-bit x86 (Kees Cook).

   - Fix error handling in the hibernation core and mark an expected
     fall-through switch in it (Chengguang Xu, Gustavo Silva).

   - Extend the generic power domains (genpd) framework to support
     attaching a device to a power domain by name (Ulf Hansson).

   - Fix device reference counting and user limits initialization in the
     devfreq core (Arvind Yadav, Matthias Kaehlcke).

   - Fix a few issues in the rk3399_dmc devfreq driver and improve its
     documentation (Enric Balletbo i Serra, Lin Huang, Nick Milner).

   - Drop a redundant error message from the exynos-ppmu devfreq driver
     (Markus Elfring)"

* tag 'pm-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (35 commits)
  PM / reboot: Eliminate race between reboot and suspend
  PM / hibernate: Mark expected switch fall-through
  cpufreq: intel_pstate: Ignore turbo active ratio in HWP
  cpufreq: Fix a circular lock dependency problem
  cpu/hotplug: Add a cpus_read_trylock() function
  x86/power/hibernate_64: Remove VLA usage
  cpufreq: trace frequency limits change
  cpufreq: intel_pstate: Show different max frequency with turbo 3 and HWP
  cpufreq: pcc-cpufreq: Disable dynamic scaling on many-CPU systems
  cpufreq: qcom-kryo: Silently error out on EPROBE_DEFER
  cpufreq / CPPC: Add cpuinfo_cur_freq support for CPPC
  cpufreq: armada-37xx: Add AVS support
  dt-bindings: marvell: Add documentation for the Armada 3700 AVS binding
  PM / devfreq: rk3399_dmc: Fix duplicated opp table on reload.
  PM / devfreq: Init user limits from OPP limits, not viceversa
  PM / devfreq: rk3399_dmc: fix spelling mistakes.
  PM / devfreq: rk3399_dmc: do not print error when get supply and clk defer.
  dt-bindings: devfreq: rk3399_dmc: move interrupts to be optional.
  PM / devfreq: rk3399_dmc: remove wait for dcf irq event.
  dt-bindings: clock: add rk3399 DDR3 standard speed bins.
  ...
2018-08-14 13:12:24 -07:00
Rafael J. Wysocki 17bc3432e3 Merge branches 'pm-core', 'pm-domains', 'pm-sleep', 'acpi-pm' and 'pm-cpuidle'
Merge changes in the PM core, system-wide PM infrastructure, generic
power domains (genpd) framework, ACPI PM infrastructure and cpuidle
for 4.19.

* pm-core:
  driver core: Add flag to autoremove device link on supplier unbind
  driver core: Rename flag AUTOREMOVE to AUTOREMOVE_CONSUMER

* pm-domains:
  PM / Domains: Introduce dev_pm_domain_attach_by_name()
  PM / Domains: Introduce option to attach a device by name to genpd
  PM / Domains: dt: Add a power-domain-names property

* pm-sleep:
  PM / reboot: Eliminate race between reboot and suspend
  PM / hibernate: Mark expected switch fall-through
  x86/power/hibernate_64: Remove VLA usage
  PM / hibernate: cast PAGE_SIZE to int when comparing with error code

* acpi-pm:
  ACPI / PM: save NVS memory for ASUS 1025C laptop
  ACPI / PM: Default to s2idle in all machines supporting LP S0

* pm-cpuidle:
  ARM: cpuidle: silence error on driver registration failure
2018-08-14 09:48:10 +02:00
Pingfan Liu 55f2503c3b PM / reboot: Eliminate race between reboot and suspend
At present, "systemctl suspend" and "shutdown" can run in parrallel. A
system can suspend after devices_shutdown(), and resume. Then the shutdown
task goes on to power off. This causes many devices are not really shut
off. Hence replacing reboot_mutex with system_transition_mutex (renamed
from pm_mutex) to achieve the exclusion. The renaming of pm_mutex as
system_transition_mutex can be better to reflect the purpose of the mutex.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-08-06 12:35:20 +02:00
Dave Hansen 0d83432811 mm: Allow non-direct-map arguments to free_reserved_area()
free_reserved_area() takes pointers as arguments to show which addresses
should be freed.  However, it does this in a somewhat ambiguous way.  If it
gets a kernel direct map address, it always works.  However, if it gets an
address that is part of the kernel image alias mapping, it can fail.

It fails if all of the following happen:
 * The specified address is part of the kernel image alias
 * Poisoning is requested (forcing a memset())
 * The address is in a read-only portion of the kernel image

The memset() fails on the read-only mapping, of course.
free_reserved_area() *is* called both on the direct map and on kernel image
alias addresses.  We've just lucked out thus far that the kernel image
alias areas it gets used on are read-write.  I'm fairly sure this has been
just a happy accident.

It is quite easy to make free_reserved_area() work for all cases: just
convert the address to a direct map address before doing the memset(), and
do this unconditionally.  There is little chance of a regression here
because we previously did a virt_to_page() on the address for the memset,
so we know these are not highmem pages for which virt_to_page() would fail.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@google.com
Cc: aarcange@redhat.com
Cc: jgross@suse.com
Cc: jpoimboe@redhat.com
Cc: gregkh@linuxfoundation.org
Cc: peterz@infradead.org
Cc: hughd@google.com
Cc: torvalds@linux-foundation.org
Cc: bp@alien8.de
Cc: luto@kernel.org
Cc: ak@linux.intel.com
Cc: Kees Cook <keescook@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Link: https://lkml.kernel.org/r/20180802225826.1287AE3E@viggo.jf.intel.com
2018-08-05 22:21:02 +02:00
Pavel Tatashin d1b47a7c9e mm: don't do zero_resv_unavail if memmap is not allocated
Moving zero_resv_unavail before memmap_init_zone(), caused a regression on
x86-32.

The cause is that we access struct pages before they are allocated when
CONFIG_FLAT_NODE_MEM_MAP is used.

free_area_init_nodes()
  zero_resv_unavail()
    mm_zero_struct_page(pfn_to_page(pfn)); <- struct page is not alloced
  free_area_init_node()
    if CONFIG_FLAT_NODE_MEM_MAP
      alloc_node_mem_map()
        memblock_virt_alloc_node_nopanic() <- struct page alloced here

On the other hand memblock_virt_alloc_node_nopanic() zeroes all the memory
that it returns, so we do not need to do zero_resv_unavail() here.

Fixes: e181ae0c5d ("mm: zero unavailable pages before memmap init")
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Tested-by: Matt Hart <matt@mattface.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-16 09:41:57 -07:00
Pavel Tatashin e181ae0c5d mm: zero unavailable pages before memmap init
We must zero struct pages for memory that is not backed by physical
memory, or kernel does not have access to.

Recently, there was a change which zeroed all memmap for all holes in
e820.  Unfortunately, it introduced a bug that is discussed here:

  https://www.spinics.net/lists/linux-mm/msg156764.html

Linus, also saw this bug on his machine, and confirmed that reverting
commit 124049decb ("x86/e820: put !E820_TYPE_RAM regions into
memblock.reserved") fixes the issue.

The problem is that we incorrectly zero some struct pages after they
were setup.

The fix is to zero unavailable struct pages prior to initializing of
struct pages.

A more detailed fix should come later that would avoid double zeroing
cases: one in __init_single_page(), the other one in
zero_resv_unavail().

Fixes: 124049decb ("x86/e820: put !E820_TYPE_RAM regions into memblock.reserved")
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-14 11:02:20 -07:00
Joe Perches 0825a6f986 mm: use octal not symbolic permissions
mm/*.c files use symbolic and octal styles for permissions.

Using octal and not symbolic permissions is preferred by many as more
readable.

https://lkml.org/lkml/2016/8/2/1945

Prefer the direct use of octal for permissions.

Done using
$ scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace mm/*.c
and some typing.

Before:	 $ git grep -P -w "0[0-7]{3,3}" mm | wc -l
44
After:	 $ git grep -P -w "0[0-7]{3,3}" mm | wc -l
86

Miscellanea:

o Whitespace neatening around these conversions.

Link: http://lkml.kernel.org/r/2e032ef111eebcd4c5952bae86763b541d373469.1522102887.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-15 07:55:25 +09:00
Vlastimil Babka 7810e6781e mm, page_alloc: do not break __GFP_THISNODE by zonelist reset
In __alloc_pages_slowpath() we reset zonelist and preferred_zoneref for
allocations that can ignore memory policies.  The zonelist is obtained
from current CPU's node.  This is a problem for __GFP_THISNODE
allocations that want to allocate on a different node, e.g.  because the
allocating thread has been migrated to a different CPU.

This has been observed to break SLAB in our 4.4-based kernel, because
there it relies on __GFP_THISNODE working as intended.  If a slab page
is put on wrong node's list, then further list manipulations may corrupt
the list because page_to_nid() is used to determine which node's
list_lock should be locked and thus we may take a wrong lock and race.

Current SLAB implementation seems to be immune by luck thanks to commit
511e3a0588 ("mm/slab: make cache_grow() handle the page allocated on
arbitrary node") but there may be others assuming that __GFP_THISNODE
works as promised.

We can fix it by simply removing the zonelist reset completely.  There
is actually no reason to reset it, because memory policies and cpusets
don't affect the zonelist choice in the first place.  This was different
when commit 183f6371aa ("mm: ignore mempolicies when using
ALLOC_NO_WATERMARK") introduced the code, as mempolicies provided their
own restricted zonelists.

We might consider this for 4.17 although I don't know if there's
anything currently broken.

SLAB is currently not affected, but in kernels older than 4.7 that don't
yet have 511e3a0588 ("mm/slab: make cache_grow() handle the page
allocated on arbitrary node") it is.  That's at least 4.4 LTS.  Older
ones I'll have to check.

So stable backports should be more important, but will have to be
reviewed carefully, as the code went through many changes.  BTW I think
that also the ac->preferred_zoneref reset is currently useless if we
don't also reset ac->nodemask from a mempolicy to NULL first (which we
probably should for the OOM victims etc?), but I would leave that for a
separate patch.

Link: http://lkml.kernel.org/r/20180525130853.13915-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Fixes: 183f6371aa ("mm: ignore mempolicies when using ALLOC_NO_WATERMARK")
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:38 -07:00
Matthew Wilcox 4da1984edb mm: combine LRU and main union in struct page
This gives us five words of space in a single union in struct page.  The
compound_mapcount moves position (from offset 24 to offset 20) on 64-bit
systems, but that does not seem likely to cause any trouble.

Link: http://lkml.kernel.org/r/20180518194519.3820-11-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:37 -07:00
Matthew Wilcox fa3015b7ee mm: use page->deferred_list
Now that we can represent the location of 'deferred_list' in C instead of
comments, make use of that ability.

Link: http://lkml.kernel.org/r/20180518194519.3820-9-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:37 -07:00
Matthew Wilcox 6e292b9be7 mm: split page_type out from _mapcount
We're already using a union of many fields here, so stop abusing the
_mapcount and make page_type its own field.  That implies renaming some of
the machinery that creates PageBuddy, PageBalloon and PageKmemcg; bring
back the PG_buddy, PG_balloon and PG_kmemcg names.

As suggested by Kirill, make page_type a bitmask.  Because it starts out
life as -1 (thanks to sharing the storage with _mapcount), setting a page
flag means clearing the appropriate bit.  This gives us space for probably
twenty or so extra bits (depending how paranoid we want to be about
_mapcount underflow).

Link: http://lkml.kernel.org/r/20180518194519.3820-3-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:37 -07:00
Huaisheng Ye a380b40abb mm/page_alloc.c: remove useless parameter of finalise_ac()
finalise_ac() has parameter order which is not used at all.  Remove it.

Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:36 -07:00
Mathieu Malaterre fb52bbaee5 mm: move is_pageblock_removable_nolock() to mm/memory_hotplug.c
is_pageblock_removable_nolock() is not used outside of
mm/memory_hotplug.c.  Move it next to unique caller
is_mem_section_removable() and make it static.

Remove prototype in <linux/memory_hotplug.h> to silence gcc warning (W=1):

  mm/page_alloc.c:7704:6: warning: no previous prototype for `is_pageblock_removable_nolock' [-Wmissing-prototypes]

Link: http://lkml.kernel.org/r/20180509190001.24789-1-malat@debian.org
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Suggested-by: Michal Hocko <mhocko@kernel.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:36 -07:00
Omar Sandoval 93781325da lockdep: fix fs_reclaim annotation
While revisiting my Btrfs swapfile series [1], I introduced a situation
in which reclaim would lock i_rwsem, and even though the swapon() path
clearly made GFP_KERNEL allocations while holding i_rwsem, I got no
complaints from lockdep.  It turns out that the rework of the fs_reclaim
annotation was broken: if the current task has PF_MEMALLOC set, we don't
acquire the dummy fs_reclaim lock, but when reclaiming we always check
this _after_ we've just set the PF_MEMALLOC flag.  In most cases, we can
fix this by moving the fs_reclaim_{acquire,release}() outside of the
memalloc_noreclaim_{save,restore}(), althought kswapd is slightly
different.  After applying this, I got the expected lockdep splats.

1: https://lwn.net/Articles/625412/

Link: http://lkml.kernel.org/r/9f8aa70652a98e98d7c4de0fc96a4addcee13efe.1523778026.git.osandov@fb.com
Fixes: d92a8cfcb3 ("locking/lockdep: Rework FS_RECLAIM annotation")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:35 -07:00
Wei Yang e69438596b mm/page_alloc: remove realsize in free_area_init_core()
Highmem's realsize always equals to freesize, so it is not necessary to
spare a variable to record this.

Link: http://lkml.kernel.org/r/20180413083859.65888-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07 17:34:35 -07:00
Michal Hocko 15c30bc090 mm, memory_hotplug: make has_unmovable_pages more robust
Oscar has reported:
: Due to an unfortunate setting with movablecore, memblocks containing bootmem
: memory (pages marked by get_page_bootmem()) ended up marked in zone_movable.
: So while trying to remove that memory, the system failed in do_migrate_range
: and __offline_pages never returned.
:
: This can be reproduced by running
: qemu-system-x86_64 -m 6G,slots=8,maxmem=8G -numa node,mem=4096M -numa node,mem=2048M
: and movablecore=4G kernel command line
:
: linux kernel: BIOS-provided physical RAM map:
: linux kernel: BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
: linux kernel: BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
: linux kernel: BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
: linux kernel: BIOS-e820: [mem 0x0000000000100000-0x00000000bffdffff] usable
: linux kernel: BIOS-e820: [mem 0x00000000bffe0000-0x00000000bfffffff] reserved
: linux kernel: BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved
: linux kernel: BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
: linux kernel: BIOS-e820: [mem 0x0000000100000000-0x00000001bfffffff] usable
: linux kernel: NX (Execute Disable) protection: active
: linux kernel: SMBIOS 2.8 present.
: linux kernel: DMI: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org
: linux kernel: Hypervisor detected: KVM
: linux kernel: e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
: linux kernel: e820: remove [mem 0x000a0000-0x000fffff] usable
: linux kernel: last_pfn = 0x1c0000 max_arch_pfn = 0x400000000
:
: linux kernel: SRAT: PXM 0 -> APIC 0x00 -> Node 0
: linux kernel: SRAT: PXM 1 -> APIC 0x01 -> Node 1
: linux kernel: ACPI: SRAT: Node 0 PXM 0 [mem 0x00000000-0x0009ffff]
: linux kernel: ACPI: SRAT: Node 0 PXM 0 [mem 0x00100000-0xbfffffff]
: linux kernel: ACPI: SRAT: Node 0 PXM 0 [mem 0x100000000-0x13fffffff]
: linux kernel: ACPI: SRAT: Node 1 PXM 1 [mem 0x140000000-0x1bfffffff]
: linux kernel: ACPI: SRAT: Node 0 PXM 0 [mem 0x1c0000000-0x43fffffff] hotplug
: linux kernel: NUMA: Node 0 [mem 0x00000000-0x0009ffff] + [mem 0x00100000-0xbfffffff] -> [mem 0x0
: linux kernel: NUMA: Node 0 [mem 0x00000000-0xbfffffff] + [mem 0x100000000-0x13fffffff] -> [mem 0
: linux kernel: NODE_DATA(0) allocated [mem 0x13ffd6000-0x13fffffff]
: linux kernel: NODE_DATA(1) allocated [mem 0x1bffd3000-0x1bfffcfff]
:
: zoneinfo shows that the zone movable is placed into both numa nodes:
: Node 0, zone  Movable
:   pages free     160140
:         min      1823
:         low      2278
:         high     2733
:         spanned  262144
:         present  262144
:         managed  245670
: Node 1, zone  Movable
:   pages free     448427
:         min      3827
:         low      4783
:         high     5739
:         spanned  524288
:         present  524288
:         managed  515766

Note how only Node 0 has a hutplugable memory region which would rule it
out from the early memblock allocations (most likely memmap).  Node1
will surely contain memmaps on the same node and those would prevent
offlining to succeed.  So this is arguably a configuration issue.
Although one could argue that we should be more clever and rule early
allocations from the zone movable.  This would be correct but probably
not worth the effort considering what a hack movablecore is.

Anyway, We could do better for those cases though.  We rely on
start_isolate_page_range resp.  has_unmovable_pages to do their job.
The first one isolates the whole range to be offlined so that we do not
allocate from it anymore and the later makes sure we are not stumbling
over non-migrateable pages.

has_unmovable_pages is overly optimistic, however.  It doesn't check all
the pages if we are withing zone_movable because we rely that those
pages will be always migrateable.  As it turns out we are still not
perfect there.  While bootmem pages in zonemovable sound like a clear
bug which should be fixed let's remove the optimization for now and warn
if we encounter unmovable pages in zone_movable in the meantime.  That
should help for now at least.

Btw.  this wasn't a real problem until commit 72b39cfc4d ("mm,
memory_hotplug: do not fail offlining too early") because we used to
have a small number of retries and then failed.  This turned out to be
too fragile though.

Link: http://lkml.kernel.org/r/20180523125555.30039-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Oscar Salvador <osalvador@techadventures.net>
Tested-by: Oscar Salvador <osalvador@techadventures.net>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-25 18:12:11 -07:00
Joonsoo Kim d883c6cf3b Revert "mm/cma: manage the memory of the CMA area by using the ZONE_MOVABLE"
This reverts the following commits that change CMA design in MM.

 3d2054ad8c ("ARM: CMA: avoid double mapping to the CMA area if CONFIG_HIGHMEM=y")

 1d47a3ec09 ("mm/cma: remove ALLOC_CMA")

 bad8c6c0b1 ("mm/cma: manage the memory of the CMA area by using the ZONE_MOVABLE")

Ville reported a following error on i386.

  Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
  microcode: microcode updated early to revision 0x4, date = 2013-06-28
  Initializing CPU#0
  Initializing HighMem for node 0 (000377fe:00118000)
  Initializing Movable for node 0 (00000001:00118000)
  BUG: Bad page state in process swapper  pfn:377fe
  page:f53effc0 count:0 mapcount:-127 mapping:00000000 index:0x0
  flags: 0x80000000()
  raw: 80000000 00000000 00000000 ffffff80 00000000 00000100 00000200 00000001
  page dumped because: nonzero mapcount
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 4.17.0-rc5-elk+ #145
  Hardware name: Dell Inc. Latitude E5410/03VXMC, BIOS A15 07/11/2013
  Call Trace:
   dump_stack+0x60/0x96
   bad_page+0x9a/0x100
   free_pages_check_bad+0x3f/0x60
   free_pcppages_bulk+0x29d/0x5b0
   free_unref_page_commit+0x84/0xb0
   free_unref_page+0x3e/0x70
   __free_pages+0x1d/0x20
   free_highmem_page+0x19/0x40
   add_highpages_with_active_regions+0xab/0xeb
   set_highmem_pages_init+0x66/0x73
   mem_init+0x1b/0x1d7
   start_kernel+0x17a/0x363
   i386_start_kernel+0x95/0x99
   startup_32_smp+0x164/0x168

The reason for this error is that the span of MOVABLE_ZONE is extended
to whole node span for future CMA initialization, and, normal memory is
wrongly freed here.  I submitted the fix and it seems to work, but,
another problem happened.

It's so late time to fix the later problem so I decide to reverting the
series.

Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Laura Abbott <labbott@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-24 10:07:50 -07:00
Pavel Tatashin 6f84f8d158 xen, mm: allow deferred page initialization for xen pv domains
Juergen Gross noticed that commit f7f99100d8 ("mm: stop zeroing memory
during allocation in vmemmap") broke XEN PV domains when deferred struct
page initialization is enabled.

This is because the xen's PagePinned() flag is getting erased from
struct pages when they are initialized later in boot.

Juergen fixed this problem by disabling deferred pages on xen pv
domains.  It is desirable, however, to have this feature available as it
reduces boot time.  This fix re-enables the feature for pv-dmains, and
fixes the problem the following way:

The fix is to delay setting PagePinned flag until struct pages for all
allocated memory are initialized, i.e.  until after free_all_bootmem().

A new x86_init.hyper op init_after_bootmem() is called to let xen know
that boot allocator is done, and hence struct pages for all the
allocated memory are now initialized.  If deferred page initialization
is enabled, the rest of struct pages are going to be initialized later
in boot once page_alloc_init_late() is called.

xen_after_bootmem() walks page table's pages and marks them pinned.

Link: http://lkml.kernel.org/r/20180226160112.24724-2-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Tested-by: Juergen Gross <jgross@suse.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Jinbum Park <jinb.park7@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Jia Zhang <zhang.jia@linux.alibaba.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:38 -07:00
Joonsoo Kim 1d47a3ec09 mm/cma: remove ALLOC_CMA
Now, all reserved pages for CMA region are belong to the ZONE_MOVABLE
and it only serves for a request with GFP_HIGHMEM && GFP_MOVABLE.

Therefore, we don't need to maintain ALLOC_CMA at all.

Link: http://lkml.kernel.org/r/1512114786-5085-3-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:32 -07:00
Joonsoo Kim bad8c6c0b1 mm/cma: manage the memory of the CMA area by using the ZONE_MOVABLE
Patch series "mm/cma: manage the memory of the CMA area by using the
ZONE_MOVABLE", v2.

0. History

This patchset is the follow-up of the discussion about the "Introduce
ZONE_CMA (v7)" [1].  Please reference it if more information is needed.

1. What does this patch do?

This patch changes the management way for the memory of the CMA area in
the MM subsystem.  Currently the memory of the CMA area is managed by
the zone where their pfn is belong to.  However, this approach has some
problems since MM subsystem doesn't have enough logic to handle the
situation that different characteristic memories are in a single zone.
To solve this issue, this patch try to manage all the memory of the CMA
area by using the MOVABLE zone.  In MM subsystem's point of view,
characteristic of the memory on the MOVABLE zone and the memory of the
CMA area are the same.  So, managing the memory of the CMA area by using
the MOVABLE zone will not have any problem.

2. Motivation

There are some problems with current approach.  See following.  Although
these problem would not be inherent and it could be fixed without this
conception change, it requires many hooks addition in various code path
and it would be intrusive to core MM and would be really error-prone.
Therefore, I try to solve them with this new approach.  Anyway,
following is the problems of the current implementation.

o CMA memory utilization

First, following is the freepage calculation logic in MM.

 - For movable allocation: freepage = total freepage
 - For unmovable allocation: freepage = total freepage - CMA freepage

Freepages on the CMA area is used after the normal freepages in the zone
where the memory of the CMA area is belong to are exhausted.  At that
moment that the number of the normal freepages is zero, so

 - For movable allocation: freepage = total freepage = CMA freepage
 - For unmovable allocation: freepage = 0

If unmovable allocation comes at this moment, allocation request would
fail to pass the watermark check and reclaim is started.  After reclaim,
there would exist the normal freepages so freepages on the CMA areas
would not be used.

FYI, there is another attempt [2] trying to solve this problem in lkml.
And, as far as I know, Qualcomm also has out-of-tree solution for this
problem.

Useless reclaim:

There is no logic to distinguish CMA pages in the reclaim path.  Hence,
CMA page is reclaimed even if the system just needs the page that can be
usable for the kernel allocation.

Atomic allocation failure:

This is also related to the fallback allocation policy for the memory of
the CMA area.  Consider the situation that the number of the normal
freepages is *zero* since the bunch of the movable allocation requests
come.  Kswapd would not be woken up due to following freepage
calculation logic.

- For movable allocation: freepage = total freepage = CMA freepage

If atomic unmovable allocation request comes at this moment, it would
fails due to following logic.

- For unmovable allocation: freepage = total freepage - CMA freepage = 0

It was reported by Aneesh [3].

Useless compaction:

Usual high-order allocation request is unmovable allocation request and
it cannot be served from the memory of the CMA area.  In compaction,
migration scanner try to migrate the page in the CMA area and make
high-order page there.  As mentioned above, it cannot be usable for the
unmovable allocation request so it's just waste.

3. Current approach and new approach

Current approach is that the memory of the CMA area is managed by the
zone where their pfn is belong to.  However, these memory should be
distinguishable since they have a strong limitation.  So, they are
marked as MIGRATE_CMA in pageblock flag and handled specially.  However,
as mentioned in section 2, the MM subsystem doesn't have enough logic to
deal with this special pageblock so many problems raised.

New approach is that the memory of the CMA area is managed by the
MOVABLE zone.  MM already have enough logic to deal with special zone
like as HIGHMEM and MOVABLE zone.  So, managing the memory of the CMA
area by the MOVABLE zone just naturally work well because constraints
for the memory of the CMA area that the memory should always be
migratable is the same with the constraint for the MOVABLE zone.

There is one side-effect for the usability of the memory of the CMA
area.  The use of MOVABLE zone is only allowed for a request with
GFP_HIGHMEM && GFP_MOVABLE so now the memory of the CMA area is also
only allowed for this gfp flag.  Before this patchset, a request with
GFP_MOVABLE can use them.  IMO, It would not be a big issue since most
of GFP_MOVABLE request also has GFP_HIGHMEM flag.  For example, file
cache page and anonymous page.  However, file cache page for blockdev
file is an exception.  Request for it has no GFP_HIGHMEM flag.  There is
pros and cons on this exception.  In my experience, blockdev file cache
pages are one of the top reason that causes cma_alloc() to fail
temporarily.  So, we can get more guarantee of cma_alloc() success by
discarding this case.

Note that there is no change in admin POV since this patchset is just
for internal implementation change in MM subsystem.  Just one minor
difference for admin is that the memory stat for CMA area will be
printed in the MOVABLE zone.  That's all.

4. Result

Following is the experimental result related to utilization problem.

8 CPUs, 1024 MB, VIRTUAL MACHINE
make -j16

<Before>
  CMA area:               0 MB            512 MB
  Elapsed-time:           92.4		186.5
  pswpin:                 82		18647
  pswpout:                160		69839

<After>
  CMA        :            0 MB            512 MB
  Elapsed-time:           93.1		93.4
  pswpin:                 84		46
  pswpout:                183		92

akpm: "kernel test robot" reported a 26% improvement in
vm-scalability.throughput:
http://lkml.kernel.org/r/20180330012721.GA3845@yexl-desktop

[1]: lkml.kernel.org/r/1491880640-9944-1-git-send-email-iamjoonsoo.kim@lge.com
[2]: https://lkml.org/lkml/2014/10/15/623
[3]: http://www.spinics.net/lists/linux-mm/msg100562.html

Link: http://lkml.kernel.org/r/1512114786-5085-2-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:32 -07:00
Joonsoo Kim d3cda2337b mm/page_alloc: don't reserve ZONE_HIGHMEM for ZONE_MOVABLE request
Freepage on ZONE_HIGHMEM doesn't work for kernel memory so it's not that
important to reserve.  When ZONE_MOVABLE is used, this problem would
theorectically cause to decrease usable memory for GFP_HIGHUSER_MOVABLE
allocation request which is mainly used for page cache and anon page
allocation.  So, fix it by setting 0 to
sysctl_lowmem_reserve_ratio[ZONE_HIGHMEM].

And, defining sysctl_lowmem_reserve_ratio array by MAX_NR_ZONES - 1 size
makes code complex.  For example, if there is highmem system, following
reserve ratio is activated for *NORMAL ZONE* which would be easyily
misleading people.

 #ifdef CONFIG_HIGHMEM
 32
 #endif

This patch also fixes this situation by defining
sysctl_lowmem_reserve_ratio array by MAX_NR_ZONES and place "#ifdef" to
right place.

Link: http://lkml.kernel.org/r/1504672525-17915-1-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Tony Lindgren <tony@atomide.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:32 -07:00
Roman Gushchin 034ebf65c3 mm: treat indirectly reclaimable memory as available in MemAvailable
Adjust /proc/meminfo MemAvailable calculation by adding the amount of
indirectly reclaimable memory (rounded to the PAGE_SIZE).

Link: http://lkml.kernel.org/r/20180305133743.12746-4-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:29 -07:00
Mike Kravetz 2c7452a075 mm/page_isolation.c: make start_isolate_page_range() fail if already isolated
start_isolate_page_range() is used to set the migrate type of a set of
pageblocks to MIGRATE_ISOLATE while attempting to start a migration
operation.  It assumes that only one thread is calling it for the
specified range.  This routine is used by CMA, memory hotplug and
gigantic huge pages.  Each of these users synchronize access to the
range within their subsystem.  However, two subsystems (CMA and gigantic
huge pages for example) could attempt operations on the same range.  If
this happens, one thread may 'undo' the work another thread is doing.
This can result in pageblocks being incorrectly left marked as
MIGRATE_ISOLATE and therefore not available for page allocation.

What is ideally needed is a way to synchronize access to a set of
pageblocks that are undergoing isolation and migration.  The only thing
we know about these pageblocks is that they are all in the same zone.  A
per-node mutex is too coarse as we want to allow multiple operations on
different ranges within the same zone concurrently.  Instead, we will
use the migration type of the pageblocks themselves as a form of
synchronization.

start_isolate_page_range sets the migration type on a set of page-
blocks going in order from the one associated with the smallest pfn to
the largest pfn.  The zone lock is acquired to check and set the
migration type.  When going through the list of pageblocks check if
MIGRATE_ISOLATE is already set.  If so, this indicates another thread is
working on this pageblock.  We know exactly which pageblocks we set, so
clean up by undo those and return -EBUSY.

This allows start_isolate_page_range to serve as a synchronization
mechanism and will allow for more general use of callers making use of
these interfaces.  Update comments in alloc_contig_range to reflect this
new functionality.

Each CPU holds the associated zone lock to modify or examine the
migration type of a pageblock.  And, it will only examine/update a
single pageblock per lock acquire/release cycle.

Link: http://lkml.kernel.org/r/20180309224731.16978-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:27 -07:00
David Rientjes 5ecd9d403a mm, page_alloc: wakeup kcompactd even if kswapd cannot free more memory
Kswapd will not wakeup if per-zone watermarks are not failing or if too
many previous attempts at background reclaim have failed.

This can be true if there is a lot of free memory available.  For high-
order allocations, kswapd is responsible for waking up kcompactd for
background compaction.  If the zone is not below its watermarks or
reclaim has recently failed (lots of free memory, nothing left to
reclaim), kcompactd does not get woken up.

When __GFP_DIRECT_RECLAIM is not allowed, allow kcompactd to still be
woken up even if kswapd will not reclaim.  This allows high-order
allocations, such as thp, to still trigger background compaction even
when the zone has an abundance of free memory.

Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803111659420.209721@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:27 -07:00
Aaron Lu 97334162e4 mm/free_pcppages_bulk: prefetch buddy while not holding lock
When a page is freed back to the global pool, its buddy will be checked
to see if it's possible to do a merge.  This requires accessing buddy's
page structure and that access could take a long time if it's cache
cold.

This patch adds a prefetch to the to-be-freed page's buddy outside of
zone->lock in hope of accessing buddy's page structure later under
zone->lock will be faster.  Since we *always* do buddy merging and check
an order-0 page's buddy to try to merge it when it goes into the main
allocator, the cacheline will always come in, i.e.  the prefetched data
will never be unused.

Normally, the number of prefetch will be pcp->batch(default=31 and has
an upper limit of (PAGE_SHIFT * 8)=96 on x86_64) but in the case of
pcp's pages get all drained, it will be pcp->count which has an upper
limit of pcp->high.  pcp->high, although has a default value of 186
(pcp->batch=31 * 6), can be changed by user through
/proc/sys/vm/percpu_pagelist_fraction and there is no software upper
limit so could be large, like several thousand.  For this reason, only
the first pcp->batch number of page's buddy structure is prefetched to
avoid excessive prefetching.

In the meantime, there are two concerns:

 1. the prefetch could potentially evict existing cachelines, especially
    for L1D cache since it is not huge

 2. there is some additional instruction overhead, namely calculating
    buddy pfn twice

For 1, it's hard to say, this microbenchmark though shows good result
but the actual benefit of this patch will be workload/CPU dependant;

For 2, since the calculation is a XOR on two local variables, it's
expected in many cases that cycles spent will be offset by reduced
memory latency later.  This is especially true for NUMA machines where
multiple CPUs are contending on zone->lock and the most time consuming
part under zone->lock is the wait of 'struct page' cacheline of the
to-be-freed pages and their buddies.

Test with will-it-scale/page_fault1 full load:

  kernel      Broadwell(2S)  Skylake(2S)   Broadwell(4S)  Skylake(4S)
  v4.16-rc2+  9034215        7971818       13667135       15677465
  patch2/3    9536374 +5.6%  8314710 +4.3% 14070408 +3.0% 16675866 +6.4%
  this patch 10180856 +6.8%  8506369 +2.3% 14756865 +4.9% 17325324 +3.9%

Note: this patch's performance improvement percent is against patch2/3.

(Changelog stolen from Dave Hansen and Mel Gorman's comments at
http://lkml.kernel.org/r/148a42d8-8306-2f2f-7f7c-86bc118f8ccd@intel.com)

[aaron.lu@intel.com: use helper function, avoid disordering pages]
  Link: http://lkml.kernel.org/r/20180301062845.26038-4-aaron.lu@intel.com
  Link: http://lkml.kernel.org/r/20180320113146.GB24737@intel.com
[aaron.lu@intel.com: v4]
  Link: http://lkml.kernel.org/r/20180301062845.26038-4-aaron.lu@intel.com
  Link: http://lkml.kernel.org/r/20180309082431.GB30868@intel.com
Link: http://lkml.kernel.org/r/20180301062845.26038-4-aaron.lu@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Suggested-by: Ying Huang <ying.huang@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:26 -07:00
Aaron Lu 0a5f4e5b45 mm/free_pcppages_bulk: do not hold lock when picking pages to free
When freeing a batch of pages from Per-CPU-Pages(PCP) back to buddy, the
zone->lock is held and then pages are chosen from PCP's migratetype
list.  While there is actually no need to do this 'choose part' under
lock since it's PCP pages, the only CPU that can touch them is us and
irq is also disabled.

Moving this part outside could reduce lock held time and improve
performance.  Test with will-it-scale/page_fault1 full load:

  kernel      Broadwell(2S)  Skylake(2S)   Broadwell(4S)  Skylake(4S)
  v4.16-rc2+  9034215        7971818       13667135       15677465
  this patch  9536374 +5.6%  8314710 +4.3% 14070408 +3.0% 16675866 +6.4%

What the test does is: starts $nr_cpu processes and each will repeatedly
do the following for 5 minutes:

 - mmap 128M anonymouse space

 - write access to that space

 - munmap.

The score is the aggregated iteration.

https://github.com/antonblanchard/will-it-scale/blob/master/tests/page_fault1.c

Link: http://lkml.kernel.org/r/20180301062845.26038-3-aaron.lu@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:26 -07:00
Aaron Lu 77ba9062e4 mm/free_pcppages_bulk: update pcp->count inside
Matthew Wilcox found that all callers of free_pcppages_bulk() currently
update pcp->count immediately after so it's natural to do it inside
free_pcppages_bulk().

No functionality or performance change is expected from this patch.

Link: http://lkml.kernel.org/r/20180301062845.26038-2-aaron.lu@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:26 -07:00
David Rientjes 7f16f91fdf mm, page_alloc: move mirrored_kernelcore to __meminitdata
mirrored_kernelcore can be in __meminitdata, so move it there.

At the same time, fixup section specifiers to be after the name of the
variable per checkpatch.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1802121623280.179479@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:25 -07:00
David Rientjes a5c6d65093 mm, page_alloc: extend kernelcore and movablecore for percent
Both kernelcore= and movablecore= can be used to define the amount of
ZONE_NORMAL and ZONE_MOVABLE on a system, respectively.  This requires
the system memory capacity to be known when specifying the command line,
however.

This introduces the ability to define both kernelcore= and movablecore=
as a percentage of total system memory.  This is convenient for systems
software that wants to define the amount of ZONE_MOVABLE, for example,
as a proportion of a system's memory rather than a hardcoded byte value.

To define the percentage, the final character of the parameter should be
a '%'.

mhocko: "why is anyone using these options nowadays?"

rientjes:
:
: Fragmentation of non-__GFP_MOVABLE pages due to low on memory
: situations can pollute most pageblocks on the system, as much as 1GB of
: slab being fragmented over 128GB of memory, for example.  When the
: amount of kernel memory is well bounded for certain systems, it is
: better to aggressively reclaim from existing MIGRATE_UNMOVABLE
: pageblocks rather than eagerly fallback to others.
:
: We have additional patches that help with this fragmentation if you're
: interested, specifically kcompactd compaction of MIGRATE_UNMOVABLE
: pageblocks triggered by fallback of non-__GFP_MOVABLE allocations and
: draining of pcp lists back to the zone free area to prevent stranding.

[rientjes@google.com: updates]
  Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1802131700160.71590@chino.kir.corp.google.com
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1802121622470.179479@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:25 -07:00
Pavel Tatashin d0dc12e86b mm/memory_hotplug: optimize memory hotplug
During memory hotplugging we traverse struct pages three times:

1. memset(0) in sparse_add_one_section()
2. loop in __add_section() to set do: set_page_node(page, nid); and
   SetPageReserved(page);
3. loop in memmap_init_zone() to call __init_single_pfn()

This patch removes the first two loops, and leaves only loop 3.  All
struct pages are initialized in one place, the same as it is done during
boot.

The benefits:

 - We improve memory hotplug performance because we are not evicting the
   cache several times and also reduce loop branching overhead.

 - Remove condition from hotpath in __init_single_pfn(), that was added
   in order to fix the problem that was reported by Bharata in the above
   email thread, thus also improve performance during normal boot.

 - Make memory hotplug more similar to the boot memory initialization
   path because we zero and initialize struct pages only in one
   function.

 - Simplifies memory hotplug struct page initialization code, and thus
   enables future improvements, such as multi-threading the
   initialization of struct pages in order to improve hotplug
   performance even further on larger machines.

[pasha.tatashin@oracle.com: v5]
  Link: http://lkml.kernel.org/r/20180228030308.1116-7-pasha.tatashin@oracle.com
Link: http://lkml.kernel.org/r/20180215165920.8570-7-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:25 -07:00
Pavel Tatashin c9e97a1997 mm: initialize pages on demand during boot
Deferred page initialization allows the boot cpu to initialize a small
subset of the system's pages early in boot, with other cpus doing the
rest later on.

It is, however, problematic to know how many pages the kernel needs
during boot.  Different modules and kernel parameters may change the
requirement, so the boot cpu either initializes too many pages or runs
out of memory.

To fix that, initialize early pages on demand.  This ensures the kernel
does the minimum amount of work to initialize pages during boot and
leaves the rest to be divided in the multithreaded initialization path
(deferred_init_memmap).

The on-demand code is permanently disabled using static branching once
deferred pages are initialized.  After the static branch is changed to
false, the overhead is up-to two branch-always instructions if the zone
watermark check fails or if rmqueue fails.

Sergey Senozhatsky noticed that while deferred pages currently make
sense only on NUMA machines (we start one thread per latency node),
CONFIG_NUMA is not a requirement for CONFIG_DEFERRED_STRUCT_PAGE_INIT,
so that is also must be addressed in the patch.

[akpm@linux-foundation.org: fix typo in comment, make deferred_pages static]
[pasha.tatashin@oracle.com: fix min() type mismatch warning]
  Link: http://lkml.kernel.org/r/20180212164543.26592-1-pasha.tatashin@oracle.com
[pasha.tatashin@oracle.com: use zone_to_nid() in deferred_grow_zone()]
  Link: http://lkml.kernel.org/r/20180214163343.21234-2-pasha.tatashin@oracle.com
[pasha.tatashin@oracle.com: might_sleep warning]
  Link: http://lkml.kernel.org/r/20180306192022.28289-1-pasha.tatashin@oracle.com
[akpm@linux-foundation.org: s/spin_lock/spin_lock_irq/ in page_alloc_init_late()]
[pasha.tatashin@oracle.com: v5]
  Link: http://lkml.kernel.org/r/20180309220807.24961-3-pasha.tatashin@oracle.com
[akpm@linux-foundation.org: tweak comments]
[pasha.tatashin@oracle.com: v6]
  Link: http://lkml.kernel.org/r/20180313182355.17669-3-pasha.tatashin@oracle.com
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20180209192216.20509-2-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Gioh Kim <gi-oh.kim@profitbricks.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Miles Chen <miles.chen@mediatek.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:25 -07:00
Pavel Tatashin 3a2d7fa8a3 mm: disable interrupts while initializing deferred pages
Vlastimil Babka reported about a window issue during which when deferred
pages are initialized, and the current version of on-demand
initialization is finished, allocations may fail.  While this is highly
unlikely scenario, since this kind of allocation request must be large,
and must come from interrupt handler, we still want to cover it.

We solve this by initializing deferred pages with interrupts disabled,
and holding node_size_lock spin lock while pages in the node are being
initialized.  The on-demand deferred page initialization that comes
later will use the same lock, and thus synchronize with
deferred_init_memmap().

It is unlikely for threads that initialize deferred pages to be
interrupted.  They run soon after smp_init(), but before modules are
initialized, and long before user space programs.  This is why there is
no adverse effect of having these threads running with interrupts
disabled.

[pasha.tatashin@oracle.com: v6]
  Link: http://lkml.kernel.org/r/20180313182355.17669-2-pasha.tatashin@oracle.com
Link: http://lkml.kernel.org/r/20180309220807.24961-2-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Gioh Kim <gi-oh.kim@profitbricks.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Miles Chen <miles.chen@mediatek.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:24 -07:00
Anshuman Khandual 310253514b mm/migrate: rename migration reason MR_CMA to MR_CONTIG_RANGE
alloc_contig_range() initiates compaction and eventual migration for the
purpose of either CMA or HugeTLB allocations.  At present, the reason
code remains the same MR_CMA for either of these cases.  Let's make it
MR_CONTIG_RANGE which will appropriately reflect the reason code in both
these cases.

Link: http://lkml.kernel.org/r/20180202091518.18798-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 21:36:24 -07:00
Linus Torvalds f5a8eb632b arch: remove obsolete architecture ports
This removes the entire architecture code for blackfin, cris, frv, m32r,
 metag, mn10300, score, and tile, including the associated device drivers.
 
 I have been working with the (former) maintainers for each one to ensure
 that my interpretation was right and the code is definitely unused in
 mainline kernels. Many had fond memories of working on the respective
 ports to start with and getting them included in upstream, but also saw
 no point in keeping the port alive without any users.
 
 In the end, it seems that while the eight architectures are extremely
 different, they all suffered the same fate: There was one company
 in charge of an SoC line, a CPU microarchitecture and a software
 ecosystem, which was more costly than licensing newer off-the-shelf
 CPU cores from a third party (typically ARM, MIPS, or RISC-V). It seems
 that all the SoC product lines are still around, but have not used the
 custom CPU architectures for several years at this point. In contrast,
 CPU instruction sets that remain popular and have actively maintained
 kernel ports tend to all be used across multiple licensees.
 
 The removal came out of a discussion that is now documented at
 https://lwn.net/Articles/748074/. Unlike the original plans, I'm not
 marking any ports as deprecated but remove them all at once after I made
 sure that they are all unused. Some architectures (notably tile, mn10300,
 and blackfin) are still being shipped in products with old kernels,
 but those products will never be updated to newer kernel releases.
 
 After this series, we still have a few architectures without mainline
 gcc support:
 
 - unicore32 and hexagon both have very outdated gcc releases, but the
   maintainers promised to work on providing something newer. At least
   in case of hexagon, this will only be llvm, not gcc.
 
 - openrisc, risc-v and nds32 are still in the process of finishing their
   support or getting it added to mainline gcc in the first place.
   They all have patched gcc-7.3 ports that work to some degree, but
   complete upstream support won't happen before gcc-8.1. Csky posted
   their first kernel patch set last week, their situation will be similar.
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 -----END PGP SIGNATURE-----

Merge tag 'arch-removal' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pul removal of obsolete architecture ports from Arnd Bergmann:
 "This removes the entire architecture code for blackfin, cris, frv,
  m32r, metag, mn10300, score, and tile, including the associated device
  drivers.

  I have been working with the (former) maintainers for each one to
  ensure that my interpretation was right and the code is definitely
  unused in mainline kernels. Many had fond memories of working on the
  respective ports to start with and getting them included in upstream,
  but also saw no point in keeping the port alive without any users.

  In the end, it seems that while the eight architectures are extremely
  different, they all suffered the same fate: There was one company in
  charge of an SoC line, a CPU microarchitecture and a software
  ecosystem, which was more costly than licensing newer off-the-shelf
  CPU cores from a third party (typically ARM, MIPS, or RISC-V). It
  seems that all the SoC product lines are still around, but have not
  used the custom CPU architectures for several years at this point. In
  contrast, CPU instruction sets that remain popular and have actively
  maintained kernel ports tend to all be used across multiple licensees.

  [ See the new nds32 port merged in the previous commit for the next
    generation of "one company in charge of an SoC line, a CPU
    microarchitecture and a software ecosystem"   - Linus ]

  The removal came out of a discussion that is now documented at
  https://lwn.net/Articles/748074/. Unlike the original plans, I'm not
  marking any ports as deprecated but remove them all at once after I
  made sure that they are all unused. Some architectures (notably tile,
  mn10300, and blackfin) are still being shipped in products with old
  kernels, but those products will never be updated to newer kernel
  releases.

  After this series, we still have a few architectures without mainline
  gcc support:

   - unicore32 and hexagon both have very outdated gcc releases, but the
     maintainers promised to work on providing something newer. At least
     in case of hexagon, this will only be llvm, not gcc.

   - openrisc, risc-v and nds32 are still in the process of finishing
     their support or getting it added to mainline gcc in the first
     place. They all have patched gcc-7.3 ports that work to some
     degree, but complete upstream support won't happen before gcc-8.1.
     Csky posted their first kernel patch set last week, their situation
     will be similar

  [ Palmer Dabbelt points out that RISC-V support is in mainline gcc
    since gcc-7, although gcc-7.3.0 is the recommended minimum  - Linus ]"

This really says it all:

 2498 files changed, 95 insertions(+), 467668 deletions(-)

* tag 'arch-removal' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: (74 commits)
  MAINTAINERS: UNICORE32: Change email account
  staging: iio: remove iio-trig-bfin-timer driver
  tty: hvc: remove tile driver
  tty: remove bfin_jtag_comm and hvc_bfin_jtag drivers
  serial: remove tile uart driver
  serial: remove m32r_sio driver
  serial: remove blackfin drivers
  serial: remove cris/etrax uart drivers
  usb: Remove Blackfin references in USB support
  usb: isp1362: remove blackfin arch glue
  usb: musb: remove blackfin port
  usb: host: remove tilegx platform glue
  pwm: remove pwm-bfin driver
  i2c: remove bfin-twi driver
  spi: remove blackfin related host drivers
  watchdog: remove bfin_wdt driver
  can: remove bfin_can driver
  mmc: remove bfin_sdh driver
  input: misc: remove blackfin rotary driver
  input: keyboard: remove bf54x driver
  ...
2018-04-02 20:20:12 -07:00
Daniel Vacek f59f1caf72 Revert "mm: page_alloc: skip over regions of invalid pfns where possible"
This reverts commit b92df1de5d ("mm: page_alloc: skip over regions of
invalid pfns where possible").  The commit is meant to be a boot init
speed up skipping the loop in memmap_init_zone() for invalid pfns.

But given some specific memory mapping on x86_64 (or more generally
theoretically anywhere but on arm with CONFIG_HAVE_ARCH_PFN_VALID) the
implementation also skips valid pfns which is plain wrong and causes
'kernel BUG at mm/page_alloc.c:1389!'

  crash> log | grep -e BUG -e RIP -e Call.Trace -e move_freepages_block -e rmqueue -e freelist -A1
  kernel BUG at mm/page_alloc.c:1389!
  invalid opcode: 0000 [#1] SMP
  --
  RIP: 0010: move_freepages+0x15e/0x160
  --
  Call Trace:
    move_freepages_block+0x73/0x80
    __rmqueue+0x263/0x460
    get_page_from_freelist+0x7e1/0x9e0
    __alloc_pages_nodemask+0x176/0x420
  --

  crash> page_init_bug -v | grep RAM
  <struct resource 0xffff88067fffd2f8>          1000 -        9bfff       System RAM (620.00 KiB)
  <struct resource 0xffff88067fffd3a0>        100000 -     430bffff       System RAM (  1.05 GiB = 1071.75 MiB = 1097472.00 KiB)
  <struct resource 0xffff88067fffd410>      4b0c8000 -     4bf9cfff       System RAM ( 14.83 MiB = 15188.00 KiB)
  <struct resource 0xffff88067fffd480>      4bfac000 -     646b1fff       System RAM (391.02 MiB = 400408.00 KiB)
  <struct resource 0xffff88067fffd560>      7b788000 -     7b7fffff       System RAM (480.00 KiB)
  <struct resource 0xffff88067fffd640>     100000000 -    67fffffff       System RAM ( 22.00 GiB)

  crash> page_init_bug | head -6
  <struct resource 0xffff88067fffd560>      7b788000 -     7b7fffff       System RAM (480.00 KiB)
  <struct page 0xffffea0001ede200>   1fffff00000000  0 <struct pglist_data 0xffff88047ffd9000> 1 <struct zone 0xffff88047ffd9800> DMA32          4096    1048575
  <struct page 0xffffea0001ede200>       505736 505344 <struct page 0xffffea0001ed8000> 505855 <struct page 0xffffea0001edffc0>
  <struct page 0xffffea0001ed8000>                0  0 <struct pglist_data 0xffff88047ffd9000> 0 <struct zone 0xffff88047ffd9000> DMA               1       4095
  <struct page 0xffffea0001edffc0>   1fffff00000400  0 <struct pglist_data 0xffff88047ffd9000> 1 <struct zone 0xffff88047ffd9800> DMA32          4096    1048575
  BUG, zones differ!

  crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b787000 7b788000
        PAGE        PHYSICAL      MAPPING       INDEX CNT FLAGS
  ffffea0001e00000  78000000                0        0  0 0
  ffffea0001ed7fc0  7b5ff000                0        0  0 0
  ffffea0001ed8000  7b600000                0        0  0 0       <<<<
  ffffea0001ede1c0  7b787000                0        0  0 0
  ffffea0001ede200  7b788000                0        0  1 1fffff00000000

Link: http://lkml.kernel.org/r/20180316143855.29838-1-neelx@redhat.com
Fixes: b92df1de5d ("mm: page_alloc: skip over regions of invalid pfns where possible")
Signed-off-by: Daniel Vacek <neelx@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-03-22 17:07:01 -07:00
Tetsuo Handa 2e517d6816 lockdep: fix fs_reclaim warning
Dave Jones reported fs_reclaim lockdep warnings.

  ============================================
  WARNING: possible recursive locking detected
  4.15.0-rc9-backup-debug+ #1 Not tainted
  --------------------------------------------
  sshd/24800 is trying to acquire lock:
   (fs_reclaim){+.+.}, at: [<0000000084f438c2>] fs_reclaim_acquire.part.102+0x5/0x30

  but task is already holding lock:
   (fs_reclaim){+.+.}, at: [<0000000084f438c2>] fs_reclaim_acquire.part.102+0x5/0x30

  other info that might help us debug this:
   Possible unsafe locking scenario:

         CPU0
         ----
    lock(fs_reclaim);
    lock(fs_reclaim);

   *** DEADLOCK ***

   May be due to missing lock nesting notation

  2 locks held by sshd/24800:
   #0:  (sk_lock-AF_INET6){+.+.}, at: [<000000001a069652>] tcp_sendmsg+0x19/0x40
   #1:  (fs_reclaim){+.+.}, at: [<0000000084f438c2>] fs_reclaim_acquire.part.102+0x5/0x30

  stack backtrace:
  CPU: 3 PID: 24800 Comm: sshd Not tainted 4.15.0-rc9-backup-debug+ #1
  Call Trace:
   dump_stack+0xbc/0x13f
   __lock_acquire+0xa09/0x2040
   lock_acquire+0x12e/0x350
   fs_reclaim_acquire.part.102+0x29/0x30
   kmem_cache_alloc+0x3d/0x2c0
   alloc_extent_state+0xa7/0x410
   __clear_extent_bit+0x3ea/0x570
   try_release_extent_mapping+0x21a/0x260
   __btrfs_releasepage+0xb0/0x1c0
   btrfs_releasepage+0x161/0x170
   try_to_release_page+0x162/0x1c0
   shrink_page_list+0x1d5a/0x2fb0
   shrink_inactive_list+0x451/0x940
   shrink_node_memcg.constprop.88+0x4c9/0x5e0
   shrink_node+0x12d/0x260
   try_to_free_pages+0x418/0xaf0
   __alloc_pages_slowpath+0x976/0x1790
   __alloc_pages_nodemask+0x52c/0x5c0
   new_slab+0x374/0x3f0
   ___slab_alloc.constprop.81+0x47e/0x5a0
   __slab_alloc.constprop.80+0x32/0x60
   __kmalloc_track_caller+0x267/0x310
   __kmalloc_reserve.isra.40+0x29/0x80
   __alloc_skb+0xee/0x390
   sk_stream_alloc_skb+0xb8/0x340
   tcp_sendmsg_locked+0x8e6/0x1d30
   tcp_sendmsg+0x27/0x40
   inet_sendmsg+0xd0/0x310
   sock_write_iter+0x17a/0x240
   __vfs_write+0x2ab/0x380
   vfs_write+0xfb/0x260
   SyS_write+0xb6/0x140
   do_syscall_64+0x1e5/0xc05
   entry_SYSCALL64_slow_path+0x25/0x25

This warning is caused by commit d92a8cfcb3 ("locking/lockdep:
Rework FS_RECLAIM annotation") which replaced the use of
lockdep_{set,clear}_current_reclaim_state() in __perform_reclaim()
and lockdep_trace_alloc() in slab_pre_alloc_hook() with
fs_reclaim_acquire()/ fs_reclaim_release().

Since __kmalloc_reserve() from __alloc_skb() adds __GFP_NOMEMALLOC |
__GFP_NOWARN to gfp_mask, and all reclaim path simply propagates
__GFP_NOMEMALLOC, fs_reclaim_acquire() in slab_pre_alloc_hook() is
trying to grab the 'fake' lock again when __perform_reclaim() already
grabbed the 'fake' lock.

The

  /* this guy won't enter reclaim */
  if ((current->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
          return false;

test which causes slab_pre_alloc_hook() to try to grab the 'fake' lock
was added by commit cf40bd16fd ("lockdep: annotate reclaim context
(__GFP_NOFS)").  But that test is outdated because PF_MEMALLOC thread
won't enter reclaim regardless of __GFP_NOMEMALLOC after commit
341ce06f69 ("page allocator: calculate the alloc_flags for allocation
only once") added the PF_MEMALLOC safeguard (

  /* Avoid recursion of direct reclaim */
  if (p->flags & PF_MEMALLOC)
          goto nopage;

in __alloc_pages_slowpath()).

Thus, let's fix outdated test by removing __GFP_NOMEMALLOC test and
allow __need_fs_reclaim() to return false.

Link: http://lkml.kernel.org/r/201802280650.FJC73911.FOSOMLJVFFQtHO@I-love.SAKURA.ne.jp
Fixes: d92a8cfcb3 ("locking/lockdep: Rework FS_RECLAIM annotation")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Tested-by: Dave Jones <davej@codemonkey.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nikolay Borisov <nborisov@suse.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>	[4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-03-22 17:07:01 -07:00
Arnd Bergmann 79375ea3ec mm: remove obsolete alloc_remap()
Tile was the only remaining architecture to implement alloc_remap(),
and since that is being removed, there is no point in keeping this
function.

Removing all callers simplifies the mem_map handling.

Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2018-03-16 10:56:13 +01:00
Ard Biesheuvel 3e04040df6 Revert "mm/page_alloc: fix memmap_init_zone pageblock alignment"
This reverts commit 864b75f9d6.

Commit 864b75f9d6 ("mm/page_alloc: fix memmap_init_zone pageblock
alignment") modified the logic in memmap_init_zone() to initialize
struct pages associated with invalid PFNs, to appease a VM_BUG_ON()
in move_freepages(), which is redundant by its own admission, and
dereferences struct page fields to obtain the zone without checking
whether the struct pages in question are valid to begin with.

Commit 864b75f9d6 only makes it worse, since the rounding it does
may cause pfn assume the same value it had in a prior iteration of
the loop, resulting in an infinite loop and a hang very early in the
boot. Also, since it doesn't perform the same rounding on start_pfn
itself but only on intermediate values following an invalid PFN, we
may still hit the same VM_BUG_ON() as before.

So instead, let's fix this at the core, and ensure that the BUG
check doesn't dereference struct page fields of invalid pages.

Fixes: 864b75f9d6 ("mm/page_alloc: fix memmap_init_zone pageblock alignment")
Tested-by: Jan Glauber <jglauber@cavium.com>
Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
Cc: Daniel Vacek <neelx@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-03-14 16:33:28 -07:00
Daniel Vacek 864b75f9d6 mm/page_alloc: fix memmap_init_zone pageblock alignment
Commit b92df1de5d ("mm: page_alloc: skip over regions of invalid pfns
where possible") introduced a bug where move_freepages() triggers a
VM_BUG_ON() on uninitialized page structure due to pageblock alignment.
To fix this, simply align the skipped pfns in memmap_init_zone() the
same way as in move_freepages_block().

Seen in one of the RHEL reports:

  crash> log | grep -e BUG -e RIP -e Call.Trace -e move_freepages_block -e rmqueue -e freelist -A1
  kernel BUG at mm/page_alloc.c:1389!
  invalid opcode: 0000 [#1] SMP
  --
  RIP: 0010:[<ffffffff8118833e>]  [<ffffffff8118833e>] move_freepages+0x15e/0x160
  RSP: 0018:ffff88054d727688  EFLAGS: 00010087
  --
  Call Trace:
   [<ffffffff811883b3>] move_freepages_block+0x73/0x80
   [<ffffffff81189e63>] __rmqueue+0x263/0x460
   [<ffffffff8118c781>] get_page_from_freelist+0x7e1/0x9e0
   [<ffffffff8118caf6>] __alloc_pages_nodemask+0x176/0x420
  --
  RIP  [<ffffffff8118833e>] move_freepages+0x15e/0x160
   RSP <ffff88054d727688>

  crash> page_init_bug -v | grep RAM
  <struct resource 0xffff88067fffd2f8>          1000 -        9bfff	System RAM (620.00 KiB)
  <struct resource 0xffff88067fffd3a0>        100000 -     430bffff	System RAM (  1.05 GiB = 1071.75 MiB = 1097472.00 KiB)
  <struct resource 0xffff88067fffd410>      4b0c8000 -     4bf9cfff	System RAM ( 14.83 MiB = 15188.00 KiB)
  <struct resource 0xffff88067fffd480>      4bfac000 -     646b1fff	System RAM (391.02 MiB = 400408.00 KiB)
  <struct resource 0xffff88067fffd560>      7b788000 -     7b7fffff	System RAM (480.00 KiB)
  <struct resource 0xffff88067fffd640>     100000000 -    67fffffff	System RAM ( 22.00 GiB)

  crash> page_init_bug | head -6
  <struct resource 0xffff88067fffd560>      7b788000 -     7b7fffff	System RAM (480.00 KiB)
  <struct page 0xffffea0001ede200>   1fffff00000000  0 <struct pglist_data 0xffff88047ffd9000> 1 <struct zone 0xffff88047ffd9800> DMA32          4096    1048575
  <struct page 0xffffea0001ede200> 505736 505344 <struct page 0xffffea0001ed8000> 505855 <struct page 0xffffea0001edffc0>
  <struct page 0xffffea0001ed8000>                0  0 <struct pglist_data 0xffff88047ffd9000> 0 <struct zone 0xffff88047ffd9000> DMA               1       4095
  <struct page 0xffffea0001edffc0>   1fffff00000400  0 <struct pglist_data 0xffff88047ffd9000> 1 <struct zone 0xffff88047ffd9800> DMA32          4096    1048575
  BUG, zones differ!

Note that this range follows two not populated sections
68000000-77ffffff in this zone.  7b788000-7b7fffff is the first one
after a gap.  This makes memmap_init_zone() skip all the pfns up to the
beginning of this range.  But this range is not pageblock (2M) aligned.
In fact no range has to be.

  crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b787000 7b788000
        PAGE        PHYSICAL      MAPPING       INDEX CNT FLAGS
  ffffea0001e00000  78000000                0        0  0 0
  ffffea0001ed7fc0  7b5ff000                0        0  0 0
  ffffea0001ed8000  7b600000                0        0  0 0	<<<<
  ffffea0001ede1c0  7b787000                0        0  0 0
  ffffea0001ede200  7b788000                0        0  1 1fffff00000000

Top part of page flags should contain nodeid and zonenr, which is not
the case for page ffffea0001ed8000 here (<<<<).

  crash> log | grep -o fffea0001ed[^\ ]* | sort -u
  fffea0001ed8000
  fffea0001eded20
  fffea0001edffc0

  crash> bt -r | grep -o fffea0001ed[^\ ]* | sort -u
  fffea0001ed8000
  fffea0001eded00
  fffea0001eded20
  fffea0001edffc0

Initialization of the whole beginning of the section is skipped up to
the start of the range due to the commit b92df1de5d.  Now any code
calling move_freepages_block() (like reusing the page from a freelist as
in this example) with a page from the beginning of the range will get
the page rounded down to start_page ffffea0001ed8000 and passed to
move_freepages() which crashes on assertion getting wrong zonenr.

  >         VM_BUG_ON(page_zone(start_page) != page_zone(end_page));

Note, page_zone() derives the zone from page flags here.

From similar machine before commit b92df1de5d28:

  crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b7fe000 7b7ff000
        PAGE        PHYSICAL      MAPPING       INDEX CNT FLAGS
  fffff73941e00000  78000000                0        0  1 1fffff00000000
  fffff73941ed7fc0  7b5ff000                0        0  1 1fffff00000000
  fffff73941ed8000  7b600000                0        0  1 1fffff00000000
  fffff73941edff80  7b7fe000                0        0  1 1fffff00000000
  fffff73941edffc0  7b7ff000 ffff8e67e04d3ae0     ad84  1 1fffff00020068 uptodate,lru,active,mappedtodisk

All the pages since the beginning of the section are initialized.
move_freepages()' not gonna blow up.

The same machine with this fix applied:

  crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b7fe000 7b7ff000
        PAGE        PHYSICAL      MAPPING       INDEX CNT FLAGS
  ffffea0001e00000  78000000                0        0  0 0
  ffffea0001e00000  7b5ff000                0        0  0 0
  ffffea0001ed8000  7b600000                0        0  1 1fffff00000000
  ffffea0001edff80  7b7fe000                0        0  1 1fffff00000000
  ffffea0001edffc0  7b7ff000 ffff88017fb13720        8  2 1fffff00020068 uptodate,lru,active,mappedtodisk

At least the bare minimum of pages is initialized preventing the crash
as well.

Customers started to report this as soon as 7.4 (where b92df1de5d was
merged in RHEL) was released.  I remember reports from
September/October-ish times.  It's not easily reproduced and happens on
a handful of machines only.  I guess that's why.  But that does not make
it less serious, I think.

Though there actually is a report here:
  https://bugzilla.kernel.org/show_bug.cgi?id=196443

And there are reports for Fedora from July:
  https://bugzilla.redhat.com/show_bug.cgi?id=1473242
and CentOS:
  https://bugs.centos.org/view.php?id=13964
and we internally track several dozens reports for RHEL bug
  https://bugzilla.redhat.com/show_bug.cgi?id=1525121

Link: http://lkml.kernel.org/r/0485727b2e82da7efbce5f6ba42524b429d0391a.1520011945.git.neelx@redhat.com
Fixes: b92df1de5d ("mm: page_alloc: skip over regions of invalid pfns where possible")
Signed-off-by: Daniel Vacek <neelx@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-03-09 16:40:01 -08:00
Juergen Gross 895f7b8e90 mm: don't defer struct page initialization for Xen pv guests
Commit f7f99100d8 ("mm: stop zeroing memory during allocation in
vmemmap") broke Xen pv domains in some configurations, as the "Pinned"
information in struct page of early page tables could get lost.

This will lead to the kernel trying to write directly into the page
tables instead of asking the hypervisor to do so.  The result is a crash
like the following:

  BUG: unable to handle kernel paging request at ffff8801ead19008
  IP: xen_set_pud+0x4e/0xd0
  PGD 1c0a067 P4D 1c0a067 PUD 23a0067 PMD 1e9de0067 PTE 80100001ead19065
  Oops: 0003 [#1] PREEMPT SMP
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.0-default+ #271
  Hardware name: Dell Inc. Latitude E6440/0159N7, BIOS A07 06/26/2014
  task: ffffffff81c10480 task.stack: ffffffff81c00000
  RIP: e030:xen_set_pud+0x4e/0xd0
  Call Trace:
   __pmd_alloc+0x128/0x140
   ioremap_page_range+0x3f4/0x410
   __ioremap_caller+0x1c3/0x2e0
   acpi_os_map_iomem+0x175/0x1b0
   acpi_tb_acquire_table+0x39/0x66
   acpi_tb_validate_table+0x44/0x7c
   acpi_tb_verify_temp_table+0x45/0x304
   acpi_reallocate_root_table+0x12d/0x141
   acpi_early_init+0x4d/0x10a
   start_kernel+0x3eb/0x4a1
   xen_start_kernel+0x528/0x532
  Code: 48 01 e8 48 0f 42 15 a2 fd be 00 48 01 d0 48 ba 00 00 00 00 00 ea ff ff 48 c1 e8 0c 48 c1 e0 06 48 01 d0 48 8b 00 f6 c4 02 75 5d <4c> 89 65 00 5b 5d 41 5c c3 65 8b 05 52 9f fe 7e 89 c0 48 0f a3
  RIP: xen_set_pud+0x4e/0xd0 RSP: ffffffff81c03cd8
  CR2: ffff8801ead19008
  ---[ end trace 38eca2e56f1b642e ]---

Avoid this problem by not deferring struct page initialization when
running as Xen pv guest.

Pavel said:

: This is unique for Xen, so this particular issue won't effect other
: configurations.  I am going to investigate if there is a way to
: re-enable deferred page initialization on xen guests.

[akpm@linux-foundation.org: explicitly include xen.h]
Link: http://lkml.kernel.org/r/20180216154101.22865-1-jgross@suse.com
Fixes: f7f99100d8 ("mm: stop zeroing memory during allocation in vmemmap")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Bob Picco <bob.picco@oracle.com>
Cc: <stable@vger.kernel.org>	[4.15.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-21 15:35:43 -08:00
Linus Torvalds 3ff1b28caa libnvdimm for 4.16
* Require struct page by default for filesystem DAX to remove a number of
   surprising failure cases.  This includes failures with direct I/O, gdb and
   fork(2).
 
 * Add support for the new Platform Capabilities Structure added to the NFIT in
   ACPI 6.2a.  This new table tells us whether the platform supports flushing
   of CPU and memory controller caches on unexpected power loss events.
 
 * Revamp vmem_altmap and dev_pagemap handling to clean up code and better
   support future future PCI P2P uses.
 
 * Deprecate the ND_IOCTL_SMART_THRESHOLD command whose payload has become
   out-of-sync with recent versions of the NVDIMM_FAMILY_INTEL spec, and
   instead rely on the generic ND_CMD_CALL approach used by the two other IOCTL
   families, NVDIMM_FAMILY_{HPE,MSFT}.
 
 * Enhance nfit_test so we can test some of the new things added in version 1.6
   of the DSM specification.  This includes testing firmware download and
   simulating the Last Shutdown State (LSS) status.
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Merge tag 'libnvdimm-for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Ross Zwisler:

 - Require struct page by default for filesystem DAX to remove a number
   of surprising failure cases. This includes failures with direct I/O,
   gdb and fork(2).

 - Add support for the new Platform Capabilities Structure added to the
   NFIT in ACPI 6.2a. This new table tells us whether the platform
   supports flushing of CPU and memory controller caches on unexpected
   power loss events.

 - Revamp vmem_altmap and dev_pagemap handling to clean up code and
   better support future future PCI P2P uses.

 - Deprecate the ND_IOCTL_SMART_THRESHOLD command whose payload has
   become out-of-sync with recent versions of the NVDIMM_FAMILY_INTEL
   spec, and instead rely on the generic ND_CMD_CALL approach used by
   the two other IOCTL families, NVDIMM_FAMILY_{HPE,MSFT}.

 - Enhance nfit_test so we can test some of the new things added in
   version 1.6 of the DSM specification. This includes testing firmware
   download and simulating the Last Shutdown State (LSS) status.

* tag 'libnvdimm-for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (37 commits)
  libnvdimm, namespace: remove redundant initialization of 'nd_mapping'
  acpi, nfit: fix register dimm error handling
  libnvdimm, namespace: make min namespace size 4K
  tools/testing/nvdimm: force nfit_test to depend on instrumented modules
  libnvdimm/nfit_test: adding support for unit testing enable LSS status
  libnvdimm/nfit_test: add firmware download emulation
  nfit-test: Add platform cap support from ACPI 6.2a to test
  libnvdimm: expose platform persistence attribute for nd_region
  acpi: nfit: add persistent memory control flag for nd_region
  acpi: nfit: Add support for detect platform CPU cache flush on power loss
  device-dax: Fix trailing semicolon
  libnvdimm, btt: fix uninitialized err_lock
  dax: require 'struct page' by default for filesystem dax
  ext2: auto disable dax instead of failing mount
  ext4: auto disable dax instead of failing mount
  mm, dax: introduce pfn_t_special()
  mm: Fix devm_memremap_pages() collision handling
  mm: Fix memory size alignment in devm_memremap_pages_release()
  memremap: merge find_dev_pagemap into get_dev_pagemap
  memremap: change devm_memremap_pages interface to use struct dev_pagemap
  ...
2018-02-06 10:41:33 -08:00
Ross Zwisler ee95f4059a Merge branch 'for-4.16/nfit' into libnvdimm-for-next 2018-02-03 00:26:26 -07:00
Michal Hocko 9bb5a391f9 mm, memory_hotplug: fix memmap initialization
Bharata has noticed that onlining a newly added memory doesn't increase
the total memory, pointing to commit f7f99100d8 ("mm: stop zeroing
memory during allocation in vmemmap") as a culprit.  This commit has
changed the way how the memory for memmaps is initialized and moves it
from the allocation time to the initialization time.  This works
properly for the early memmap init path.

It doesn't work for the memory hotplug though because we need to mark
page as reserved when the sparsemem section is created and later
initialize it completely during onlining.  memmap_init_zone is called in
the early stage of onlining.  With the current code it calls
__init_single_page and as such it clears up the whole stage and
therefore online_pages_range skips those pages.

Fix this by skipping mm_zero_struct_page in __init_single_page for
memory hotplug path.  This is quite uggly but unifying both early init
and memory hotplug init paths is a large project.  Make sure we plug the
regression at least.

Link: http://lkml.kernel.org/r/20180130101141.GW21609@dhcp22.suse.cz
Fixes: f7f99100d8 ("mm: stop zeroing memory during allocation in vmemmap")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Tested-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Bob Picco <bob.picco@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31 17:18:40 -08:00
Shile Zhang 3c2c648842 mm/page_alloc.c: fix typos in comments
Link: http://lkml.kernel.org/r/1515485774-4768-1-git-send-email-zhangshile@gmail.com
Signed-off-by: Shile Zhang <zhangshile@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31 17:18:39 -08:00
Jiankang Chen 48128397b0 mm/page_alloc.c: fix comment in __get_free_pages()
__get_free_pages() will return a virtual address, but it is not just a
32-bit address, for example on a 64-bit system.  And this comment really
confuses new readers of mm.

Link: http://lkml.kernel.org/r/1511780964-64864-1-git-send-email-chenjiankang1@huawei.com
Signed-off-by: Jiankang Chen <chenjiankang1@huawei.com>
Reported-by: Hanjun Guo <guohanjun@huawei.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31 17:18:36 -08:00
Pavel Tatashin 80b1f41c09 mm: split deferred_init_range into initializing and freeing parts
In deferred_init_range() we initialize struct pages, and also free them
to buddy allocator.  We do it in separate loops, because buddy page is
computed ahead, so we do not want to access a struct page that has not
been initialized yet.

There is still, however, a corner case where it is potentially possible
to access uninitialized struct page: this is when buddy page is from the
next memblock range.

This patch fixes this problem by splitting deferred_init_range() into
two functions: one to initialize struct pages, and another to free them.

In addition, this patch brings the following improvements:
 - Get rid of __def_free() helper function. And simplifies loop logic by
   adding a new pfn validity check function: deferred_pfn_valid().
 - Reduces number of variables that we track. So, there is a higher
   chance that we will avoid using stack to store/load variables inside
   hot loops.
 - Enables future multi-threading of these functions: do initialization
   in multiple threads, wait for all threads to finish, do freeing part
   in multithreading.

Tested on x86 with 1T of memory to make sure no regressions are
introduced.

[akpm@linux-foundation.org: fix spello in comment]
Link: http://lkml.kernel.org/r/20171107150446.32055-2-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-31 17:18:36 -08:00
Christoph Hellwig a99583e780 mm: pass the vmem_altmap to memmap_init_zone
Pass the vmem_altmap two levels down instead of needing a lookup.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Dave Young e8c24773d6 mm: check pfn_valid first in zero_resv_unavail
With latest kernel I get below bug while testing kdump:

  BUG: unable to handle kernel paging request at ffffea00034b1040
  IP: zero_resv_unavail+0xbd/0x126
  PGD 37b98067 P4D 37b98067 PUD 37b97067 PMD 0
  Oops: 0002 [#1] SMP
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 4.15.0-rc1+ #316
  Hardware name: LENOVO 20ARS1BJ02/20ARS1BJ02, BIOS GJET92WW (2.42 ) 03/03/2017
  task: ffffffff81a0e4c0 task.stack: ffffffff81a00000
  RIP: 0010:zero_resv_unavail+0xbd/0x126
  RSP: 0000:ffffffff81a03d88 EFLAGS: 00010006
  RAX: 0000000000000000 RBX: ffffea00034b1040 RCX: 0000000000000010
  RDX: 0000000000000000 RSI: 0000000000000092 RDI: ffffea00034b1040
  RBP: 00000000000d2c41 R08: 00000000000000c0 R09: 0000000000000a0d
  R10: 0000000000000002 R11: 0000000000007f01 R12: ffffffff81a03d90
  R13: ffffea0000000000 R14: 0000000000000063 R15: 0000000000000062
  FS:  0000000000000000(0000) GS:ffffffff81c73000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffffea00034b1040 CR3: 0000000037609000 CR4: 00000000000606b0
  Call Trace:
   ? free_area_init_nodes+0x640/0x664
   ? zone_sizes_init+0x58/0x72
   ? setup_arch+0xb50/0xc6c
   ? start_kernel+0x64/0x43d
   ? secondary_startup_64+0xa5/0xb0
  Code: c1 e8 0c 48 39 d8 76 27 48 89 de 48 c1 e3 06 48 c7 c7 7a 87 79 81 e8 b0 c0 3e ff 4c 01 eb b9 10 00 00 00 31 c0 48 89 df 49 ff c6 <f3> ab eb bc 6a 00 49 c7 c0 f0 93 d1 81 31 d2 83 ce ff 41 54 49
  RIP: zero_resv_unavail+0xbd/0x126 RSP: ffffffff81a03d88
  CR2: ffffea00034b1040
  ---[ end trace f5ba9e8f73c7ee26 ]---

This is introduced by commit a4a3ede213 ("mm: zero reserved and
unavailable struct pages").

The reason is some efi reserved boot ranges is not reported in E820 ram.
In my case it is a bgrt buffer:

  efi: mem00: [Boot Data          |RUN|  |  |  |  |  |  |   |WB|WT|WC|UC] range=[0x00000000d2c41000-0x00000000d2c85fff] (0MB)

Use "add_efi_memmap" can workaround the problem with another fix:

  http://lkml.kernel.org/r/20171130052327.GA3500@dhcp-128-65.nay.redhat.com

In zero_resv_unavail it would be better to check pfn_valid first before
zero the page struct.  This fixes the problem and potential other
similar problems.  Also as Pavel Tatashin suggested checks pfn_valid at
the beginning of the section.

The range is backed by real memory.  The memory range is efi "Boot
Service Data", that means after ExitBootServices() these ranges can be
used as system ram.  But some of them need to be reserved, for example
the bgrt image address in an acpi table, if the image memory is freed
then kexec reboot will fail because kexec inherit same acpi table to
initialize the driver.

Link: http://lkml.kernel.org/r/20171201095048.GA3084@dhcp-128-65.nay.redhat.com
Fixes: a4a3ede213 ("mm: zero reserved and unavailable struct pages")
Signed-off-by: Dave Young <dyoung@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-01-04 16:45:09 -08:00
Lucas Stach c24ad77d96 mm/page_alloc.c: avoid excessive IRQ disabled times in free_unref_page_list()
Since commit 9cca35d42e ("mm, page_alloc: enable/disable IRQs once
when freeing a list of pages") we see excessive IRQ disabled times of up
to 25ms on an embedded ARM system (tracing overhead included).

This is due to graphics buffers being freed back to the system via
release_pages().  Graphics buffers can be huge, so it's not hard to hit
cases where the list of pages to free has 2048 entries.  Disabling IRQs
while freeing all those pages is clearly not a good idea.

Introduce a batch limit, which allows IRQ servicing once every few
pages.  The batch count is the same as used in other parts of the MM
subsystem when dealing with IRQ disabled regions.

Link: http://lkml.kernel.org/r/20171207170314.4419-1-l.stach@pengutronix.de
Fixes: 9cca35d42e ("mm, page_alloc: enable/disable IRQs once when freeing a list of pages")
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-12-14 16:00:48 -08:00
Mike Kravetz 63cd448908 mm/cma: fix alloc_contig_range ret code/potential leak
If the call __alloc_contig_migrate_range() in alloc_contig_range returns
-EBUSY, processing continues so that test_pages_isolated() is called
where there is a tracepoint to identify the busy pages.  However, it is
possible for busy pages to become available between the calls to these
two routines.  In this case, the range of pages may be allocated.
Unfortunately, the original return code (ret == -EBUSY) is still set and
returned to the caller.  Therefore, the caller believes the pages were
not allocated and they are leaked.

Update the comment to indicate that allocation is still possible even if
__alloc_contig_migrate_range returns -EBUSY.  Also, clear return code in
this case so that it is not accidentally used or returned to caller.

Link: http://lkml.kernel.org/r/20171122185214.25285-1-mike.kravetz@oracle.com
Fixes: 8ef5849fa8 ("mm/cma: always check which page caused allocation failure")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-29 18:40:42 -08:00
Michal Hocko 4b81cb2ff6 mm, memory_hotplug: do not back off draining pcp free pages from kworker context
drain_all_pages backs off when called from a kworker context since
commit 0ccce3b924 ("mm, page_alloc: drain per-cpu pages from workqueue
context") because the original IPI based pcp draining has been replaced
by a WQ based one and the check wanted to prevent from recursion and
inter workers dependencies.  This has made some sense at the time
because the system WQ has been used and one worker holding the lock
could be blocked while waiting for new workers to emerge which can be a
problem under OOM conditions.

Since then commit ce612879dd ("mm: move pcp and lru-pcp draining into
single wq") has moved draining to a dedicated (mm_percpu_wq) WQ with a
rescuer so we shouldn't depend on any other WQ activity to make a
forward progress so calling drain_all_pages from a worker context is
safe as long as this doesn't happen from mm_percpu_wq itself which is
not the case because all workers are required to _not_ depend on any MM
locks.

Why is this a problem in the first place? ACPI driven memory hot-remove
(acpi_device_hotplug) is executed from the worker context.  We end up
calling __offline_pages to free all the pages and that requires both
lru_add_drain_all_cpuslocked and drain_all_pages to do their job
otherwise we can have dangling pages on pcp lists and fail the offline
operation (__test_page_isolated_in_pageblock would see a page with 0 ref
count but without PageBuddy set).

Fix the issue by removing the worker check in drain_all_pages.
lru_add_drain_all_cpuslocked doesn't have this restriction so it works
as expected.

Link: http://lkml.kernel.org/r/20170828093341.26341-1-mhocko@kernel.org
Fixes: 0ccce3b924 ("mm, page_alloc: drain per-cpu pages from workqueue context")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>	[4.11+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-29 18:40:42 -08:00
Vlastimil Babka 2583d67132 mm, compaction: split off flag for not updating skip hints
Pageblock skip hints were added as a heuristic for compaction, which
shares core code with CMA.  Since CMA reliability would suffer from the
heuristics, compact_control flag ignore_skip_hint was added for the CMA
use case.  Since 6815bf3f23 ("mm/compaction: respect ignore_skip_hint
in update_pageblock_skip") the flag also means that CMA won't *update*
the skip hints in addition to ignoring them.

Today, direct compaction can also ignore the skip hints in the last
resort attempt, but there's no reason not to set them when isolation
fails in such case.  Thus, this patch splits off a new no_set_skip_hint
flag to avoid the updating, which only CMA sets.  This should improve
the heuristics a bit, and allow us to simplify the persistent skip bit
handling as the next step.

Link: http://lkml.kernel.org/r/20171102121706.21504-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-17 16:10:00 -08:00
Oscar Salvador 0cd842f970 mm: make alloc_node_mem_map a void call if we don't have CONFIG_FLAT_NODE_MEM_MAP
free_area_init_node() calls alloc_node_mem_map(), but this function does
nothing unless we have CONFIG_FLAT_NODE_MEM_MAP.

As a cleanup, we can move the "#ifdef CONFIG_FLAT_NODE_MEM_MAP" within
alloc_node_mem_map() out of the function, and define a
alloc_node_mem_map() { } when CONFIG_FLAT_NODE_MEM_MAP is not present.

This also moves the printk that lays within the "#ifdef
CONFIG_FLAT_NODE_MEM_MAP" block from free_area_init_node() to
alloc_node_mem_map(), getting rid of the "#ifdef
CONFIG_FLAT_NODE_MEM_MAP" in free_area_init_node().

[akpm@linux-foundation.org: clean up the printk while we're there]
Link: http://lkml.kernel.org/r/20171114111935.GA11758@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@techadventures.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:07 -08:00
Michal Hocko 0205f75571 mm: simplify nodemask printing
alloc_warn() and dump_header() have to explicitly handle NULL nodemask
which forces both paths to use pr_cont.  We can do better.  printk
already handles NULL pointers properly so all we need is to teach
nodemask_pr_args to handle NULL nodemask carefully.  This allows
simplification of both alloc_warn() and dump_header() and gets rid of
pr_cont altogether.

This patch has been motivated by patch from Joe Perches

  http://lkml.kernel.org/r/b31236dfe3fc924054fd7842bde678e71d193638.1509991345.git.joe@perches.com

[akpm@linux-foundation.org: fix tile warning, per Arnd]
Link: http://lkml.kernel.org/r/20171109100531.3cn2hcqnuj7mjaju@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Joe Perches <joe@perches.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:07 -08:00
Pavel Tatashin d135e57502 mm/page_alloc.c: broken deferred calculation
In reset_deferred_meminit() we determine number of pages that must not
be deferred.  We initialize pages for at least 2G of memory, but also
pages for reserved memory in this node.

The reserved memory is determined in this function:
memblock_reserved_memory_within(), which operates over physical
addresses, and returns size in bytes.  However, reset_deferred_meminit()
assumes that that this function operates with pfns, and returns page
count.

The result is that in the best case machine boots slower than expected
due to initializing more pages than needed in single thread, and in the
worst case panics because fewer than needed pages are initialized early.

Link: http://lkml.kernel.org/r/20171021011707.15191-1-pasha.tatashin@oracle.com
Fixes: 864b9a393d ("mm: consider memblock reservations for deferred memory initialization sizing")
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:07 -08:00
Tetsuo Handa 400e22499d mm: don't warn about allocations which stall for too long
Commit 63f53dea0c ("mm: warn about allocations which stall for too
long") was a great step for reducing possibility of silent hang up
problem caused by memory allocation stalls.  But this commit reverts it,
for it is possible to trigger OOM lockup and/or soft lockups when many
threads concurrently called warn_alloc() (in order to warn about memory
allocation stalls) due to current implementation of printk(), and it is
difficult to obtain useful information due to limitation of synchronous
warning approach.

Current printk() implementation flushes all pending logs using the
context of a thread which called console_unlock().  printk() should be
able to flush all pending logs eventually unless somebody continues
appending to printk() buffer.

Since warn_alloc() started appending to printk() buffer while waiting
for oom_kill_process() to make forward progress when oom_kill_process()
is processing pending logs, it became possible for warn_alloc() to force
oom_kill_process() loop inside printk().  As a result, warn_alloc()
significantly increased possibility of preventing oom_kill_process()
from making forward progress.

---------- Pseudo code start ----------
Before warn_alloc() was introduced:

  retry:
    if (mutex_trylock(&oom_lock)) {
      while (atomic_read(&printk_pending_logs) > 0) {
        atomic_dec(&printk_pending_logs);
        print_one_log();
      }
      // Send SIGKILL here.
      mutex_unlock(&oom_lock)
    }
    goto retry;

After warn_alloc() was introduced:

  retry:
    if (mutex_trylock(&oom_lock)) {
      while (atomic_read(&printk_pending_logs) > 0) {
        atomic_dec(&printk_pending_logs);
        print_one_log();
      }
      // Send SIGKILL here.
      mutex_unlock(&oom_lock)
    } else if (waited_for_10seconds()) {
      atomic_inc(&printk_pending_logs);
    }
    goto retry;
---------- Pseudo code end ----------

Although waited_for_10seconds() becomes true once per 10 seconds,
unbounded number of threads can call waited_for_10seconds() at the same
time.  Also, since threads doing waited_for_10seconds() keep doing
almost busy loop, the thread doing print_one_log() can use little CPU
resource.  Therefore, this situation can be simplified like

---------- Pseudo code start ----------
  retry:
    if (mutex_trylock(&oom_lock)) {
      while (atomic_read(&printk_pending_logs) > 0) {
        atomic_dec(&printk_pending_logs);
        print_one_log();
      }
      // Send SIGKILL here.
      mutex_unlock(&oom_lock)
    } else {
      atomic_inc(&printk_pending_logs);
    }
    goto retry;
---------- Pseudo code end ----------

when printk() is called faster than print_one_log() can process a log.

One of possible mitigation would be to introduce a new lock in order to
make sure that no other series of printk() (either oom_kill_process() or
warn_alloc()) can append to printk() buffer when one series of printk()
(either oom_kill_process() or warn_alloc()) is already in progress.

Such serialization will also help obtaining kernel messages in readable
form.

---------- Pseudo code start ----------
  retry:
    if (mutex_trylock(&oom_lock)) {
      mutex_lock(&oom_printk_lock);
      while (atomic_read(&printk_pending_logs) > 0) {
        atomic_dec(&printk_pending_logs);
        print_one_log();
      }
      // Send SIGKILL here.
      mutex_unlock(&oom_printk_lock);
      mutex_unlock(&oom_lock)
    } else {
      if (mutex_trylock(&oom_printk_lock)) {
        atomic_inc(&printk_pending_logs);
        mutex_unlock(&oom_printk_lock);
      }
    }
    goto retry;
---------- Pseudo code end ----------

But this commit does not go that direction, for we don't want to
introduce a new lock dependency, and we unlikely be able to obtain
useful information even if we serialized oom_kill_process() and
warn_alloc().

Synchronous approach is prone to unexpected results (e.g.  too late [1],
too frequent [2], overlooked [3]).  As far as I know, warn_alloc() never
helped with providing information other than "something is going wrong".
I want to consider asynchronous approach which can obtain information
during stalls with possibly relevant threads (e.g.  the owner of
oom_lock and kswapd-like threads) and serve as a trigger for actions
(e.g.  turn on/off tracepoints, ask libvirt daemon to take a memory dump
of stalling KVM guest for diagnostic purpose).

This commit temporarily loses ability to report e.g.  OOM lockup due to
unable to invoke the OOM killer due to !__GFP_FS allocation request.
But asynchronous approach will be able to detect such situation and emit
warning.  Thus, let's remove warn_alloc().

[1] https://bugzilla.kernel.org/show_bug.cgi?id=192981
[2] http://lkml.kernel.org/r/CAM_iQpWuPVGc2ky8M-9yukECtS+zKjiDasNymX7rMcBjBFyM_A@mail.gmail.com
[3] commit db73ee0d46 ("mm, vmscan: do not loop on too_many_isolated for ever"))

Link: http://lkml.kernel.org/r/1509017339-4802-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Reported-by: yuwang.yuwang <yuwang.yuwang@alibaba-inc.com>
Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:07 -08:00
Vlastimil Babka b050e3769c mm, page_alloc: fix potential false positive in __zone_watermark_ok
Since commit 97a16fc82a ("mm, page_alloc: only enforce watermarks for
order-0 allocations"), __zone_watermark_ok() check for high-order
allocations will shortcut per-migratetype free list checks for
ALLOC_HARDER allocations, and return true as long as there's free page
of any migratetype.  The intention is that ALLOC_HARDER can allocate
from MIGRATE_HIGHATOMIC free lists, while normal allocations can't.

However, as a side effect, the watermark check will then also return
true when there are pages only on the MIGRATE_ISOLATE list, or (prior to
CMA conversion to ZONE_MOVABLE) on the MIGRATE_CMA list.  Since the
allocation cannot actually obtain isolated pages, and might not be able
to obtain CMA pages, this can result in a false positive.

The condition should be rare and perhaps the outcome is not a fatal one.
Still, it's better if the watermark check is correct.  There also
shouldn't be a performance tradeoff here.

Link: http://lkml.kernel.org/r/20171102125001.23708-1-vbabka@suse.cz
Fixes: 97a16fc82a ("mm, page_alloc: only enforce watermarks for order-0 allocations")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:07 -08:00
Kemi Wang 4518085e12 mm, sysctl: make NUMA stats configurable
This is the second step which introduces a tunable interface that allow
numa stats configurable for optimizing zone_statistics(), as suggested
by Dave Hansen and Ying Huang.

=========================================================================

When page allocation performance becomes a bottleneck and you can
tolerate some possible tool breakage and decreased numa counter
precision, you can do:

	echo 0 > /proc/sys/vm/numa_stat

In this case, numa counter update is ignored.  We can see about
*4.8%*(185->176) drop of cpu cycles per single page allocation and
reclaim on Jesper's page_bench01 (single thread) and *8.1%*(343->315)
drop of cpu cycles per single page allocation and reclaim on Jesper's
page_bench03 (88 threads) running on a 2-Socket Broadwell-based server
(88 threads, 126G memory).

Benchmark link provided by Jesper D Brouer (increase loop times to
10000000):

  https://github.com/netoptimizer/prototype-kernel/tree/master/kernel/mm/bench

=========================================================================

When page allocation performance is not a bottleneck and you want all
tooling to work, you can do:

	echo 1 > /proc/sys/vm/numa_stat

This is system default setting.

Many thanks to Michal Hocko, Dave Hansen, Ying Huang and Vlastimil Babka
for comments to help improve the original patch.

[keescook@chromium.org: make sure mutex is a global static]
  Link: http://lkml.kernel.org/r/20171107213809.GA4314@beast
Link: http://lkml.kernel.org/r/1508290927-8518-1-git-send-email-kemi.wang@intel.com
Signed-off-by: Kemi Wang <kemi.wang@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Suggested-by: Ying Huang <ying.huang@intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Luis R . Rodriguez" <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christopher Lameter <cl@linux.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:07 -08:00
Vlastimil Babka 0fac3ba527 mm, page_alloc: simplify list handling in rmqueue_bulk()
rmqueue_bulk() fills an empty pcplist with pages from the free list.  It
tries to preserve increasing order by pfn to the caller, because it
leads to better performance with some I/O controllers, as explained in
commit e084b2d95e ("page-allocator: preserve PFN ordering when
__GFP_COLD is set").

To preserve the order, it's sufficient to add pages to the tail of the
list as they are retrieved.  The current code instead adds to the head
of the list, but then updates the list head pointer to the last added
page, in each step.  This does result in the same order, but is
needlessly confusing and potentially wasteful, with no apparent benefit.
This patch simplifies the code and adjusts comment accordingly.

Link: http://lkml.kernel.org/r/f6505442-98a9-12e4-b2cd-0fa83874c159@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:06 -08:00
Mel Gorman 453f85d43f mm: remove __GFP_COLD
As the page free path makes no distinction between cache hot and cold
pages, there is no real useful ordering of pages in the free list that
allocation requests can take advantage of.  Juding from the users of
__GFP_COLD, it is likely that a number of them are the result of copying
other sites instead of actually measuring the impact.  Remove the
__GFP_COLD parameter which simplifies a number of paths in the page
allocator.

This is potentially controversial but bear in mind that the size of the
per-cpu pagelists versus modern cache sizes means that the whole per-cpu
list can often fit in the L3 cache.  Hence, there is only a potential
benefit for microbenchmarks that alloc/free pages in a tight loop.  It's
even worse when THP is taken into account which has little or no chance
of getting a cache-hot page as the per-cpu list is bypassed and the
zeroing of multiple pages will thrash the cache anyway.

The truncate microbenchmarks are not shown as this patch affects the
allocation path and not the free path.  A page fault microbenchmark was
tested but it showed no sigificant difference which is not surprising
given that the __GFP_COLD branches are a miniscule percentage of the
fault path.

Link: http://lkml.kernel.org/r/20171018075952.10627-9-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:06 -08:00
Mel Gorman 2d4894b5d2 mm: remove cold parameter from free_hot_cold_page*
Most callers users of free_hot_cold_page claim the pages being released
are cache hot.  The exception is the page reclaim paths where it is
likely that enough pages will be freed in the near future that the
per-cpu lists are going to be recycled and the cache hotness information
is lost.  As no one really cares about the hotness of pages being
released to the allocator, just ditch the parameter.

The APIs are renamed to indicate that it's no longer about hot/cold
pages.  It should also be less confusing as there are subtle differences
between them.  __free_pages drops a reference and frees a page when the
refcount reaches zero.  free_hot_cold_page handled pages whose refcount
was already zero which is non-obvious from the name.  free_unref_page
should be more obvious.

No performance impact is expected as the overhead is marginal.  The
parameter is removed simply because it is a bit stupid to have a useless
parameter copied everywhere.

[mgorman@techsingularity.net: add pages to head, not tail]
  Link: http://lkml.kernel.org/r/20171019154321.qtpzaeftoyyw4iey@techsingularity.net
Link: http://lkml.kernel.org/r/20171018075952.10627-8-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:06 -08:00
Mel Gorman 9cca35d42e mm, page_alloc: enable/disable IRQs once when freeing a list of pages
Patch series "Follow-up for speed up page cache truncation", v2.

This series is a follow-on for Jan Kara's series "Speed up page cache
truncation" series.  We both ended up looking at the same problem but
saw different problems based on the same data.  This series builds upon
his work.

A variety of workloads were compared on four separate machines but each
machine showed gains albeit at different levels.  Minimally, some of the
differences are due to NUMA where truncating data from a remote node is
slower than a local node.  The workloads checked were

o sparse truncate microbenchmark, tiny
o sparse truncate microbenchmark, large
o reaim-io disk workfile
o dbench4 (modified by mmtests to produce more stable results)
o filebench varmail configuration for small memory size
o bonnie, directory operations, working set size 2*RAM

reaim-io, dbench and filebench all showed minor gains.  Truncation does
not dominate those workloads but were tested to ensure no other
regressions.  They will not be reported further.

The sparse truncate microbench was written by Jan.  It creates a number
of files and then times how long it takes to truncate each one.  The
"tiny" configuraiton creates a number of files that easily fits in
memory and times how long it takes to truncate files with page cache.
The large configuration uses enough files to have data that is twice the
size of memory and so timings there include truncating page cache and
working set shadow entries in the radix tree.

Patches 1-4 are the most relevant parts of this series.  Patches 5-8 are
optional as they are deleting code that is essentially useless but has a
negligible performance impact.

The changelogs have more information on performance but just for bonnie
delete options, the main comparison is

bonnie
                                      4.14.0-rc5             4.14.0-rc5             4.14.0-rc5
                                          jan-v2                vanilla                 mel-v2
Hmean     SeqCreate ops         76.20 (   0.00%)       75.80 (  -0.53%)       76.80 (   0.79%)
Hmean     SeqCreate read        85.00 (   0.00%)       85.00 (   0.00%)       85.00 (   0.00%)
Hmean     SeqCreate del      13752.31 (   0.00%)    12090.23 ( -12.09%)    15304.84 (  11.29%)
Hmean     RandCreate ops        76.00 (   0.00%)       75.60 (  -0.53%)       77.00 (   1.32%)
Hmean     RandCreate read       96.80 (   0.00%)       96.80 (   0.00%)       97.00 (   0.21%)
Hmean     RandCreate del     13233.75 (   0.00%)    11525.35 ( -12.91%)    14446.61 (   9.16%)

Jan's series is the baseline and the vanilla kernel is 12% slower where
as this series on top gains another 11%.  This is from a different
machine than the data in the changelogs but the detailed data was not
collected as there was no substantial change in v2.

This patch (of 8):

Freeing a list of pages current enables/disables IRQs for each page
freed.  This patch splits freeing a list of pages into two operations --
preparing the pages for freeing and the actual freeing.  This is a
tradeoff - we're taking two passes of the list to free in exchange for
avoiding multiple enable/disable of IRQs.

sparsetruncate (tiny)
                              4.14.0-rc4             4.14.0-rc4
                           janbatch-v1r1            oneirq-v1r1
Min          Time      149.00 (   0.00%)      141.00 (   5.37%)
1st-qrtle    Time      150.00 (   0.00%)      142.00 (   5.33%)
2nd-qrtle    Time      151.00 (   0.00%)      142.00 (   5.96%)
3rd-qrtle    Time      151.00 (   0.00%)      143.00 (   5.30%)
Max-90%      Time      153.00 (   0.00%)      144.00 (   5.88%)
Max-95%      Time      155.00 (   0.00%)      147.00 (   5.16%)
Max-99%      Time      201.00 (   0.00%)      195.00 (   2.99%)
Max          Time      236.00 (   0.00%)      230.00 (   2.54%)
Amean        Time      152.65 (   0.00%)      144.37 (   5.43%)
Stddev       Time        9.78 (   0.00%)       10.44 (  -6.72%)
Coeff        Time        6.41 (   0.00%)        7.23 ( -12.84%)
Best99%Amean Time      152.07 (   0.00%)      143.72 (   5.50%)
Best95%Amean Time      150.75 (   0.00%)      142.37 (   5.56%)
Best90%Amean Time      150.59 (   0.00%)      142.19 (   5.58%)
Best75%Amean Time      150.36 (   0.00%)      141.92 (   5.61%)
Best50%Amean Time      150.04 (   0.00%)      141.69 (   5.56%)
Best25%Amean Time      149.85 (   0.00%)      141.38 (   5.65%)

With a tiny number of files, each file truncated has resident page cache
and it shows that time to truncate is roughtly 5-6% with some minor
jitter.

                                      4.14.0-rc4             4.14.0-rc4
                                   janbatch-v1r1            oneirq-v1r1
Hmean     SeqCreate ops         65.27 (   0.00%)       81.86 (  25.43%)
Hmean     SeqCreate read        39.48 (   0.00%)       47.44 (  20.16%)
Hmean     SeqCreate del      24963.95 (   0.00%)    26319.99 (   5.43%)
Hmean     RandCreate ops        65.47 (   0.00%)       82.01 (  25.26%)
Hmean     RandCreate read       42.04 (   0.00%)       51.75 (  23.09%)
Hmean     RandCreate del     23377.66 (   0.00%)    23764.79 (   1.66%)

As expected, there is a small gain for the delete operation.

[mgorman@techsingularity.net: use page_private and set_page_private helpers]
  Link: http://lkml.kernel.org/r/20171018101547.mjycw7zreb66jzpa@techsingularity.net
Link: http://lkml.kernel.org/r/20171018075952.10627-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Jan Kara <jack@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:06 -08:00
Aaron Lu 85ccc8fa81 mm/page_alloc: make sure __rmqueue() etc are always inline
__rmqueue(), __rmqueue_fallback(), __rmqueue_smallest() and
__rmqueue_cma_fallback() are all in page allocator's hot path and better
be finished as soon as possible.  One way to make them faster is by making
them inline.  But as Andrew Morton and Andi Kleen pointed out:

  https://lkml.org/lkml/2017/10/10/1252
  https://lkml.org/lkml/2017/10/10/1279

To make sure they are inlined, we should use __always_inline for them.

With the will-it-scale/page_fault1/process benchmark, when using nr_cpu
processes to stress buddy, the results for will-it-scale.processes with
and without the patch are:

On a 2-sockets Intel-Skylake machine:

   compiler          base        head
  gcc-4.4.7       6496131     6911823 +6.4%
  gcc-4.9.4       7225110     7731072 +7.0%
  gcc-5.4.1       7054224     7688146 +9.0%
  gcc-6.2.0       7059794     7651675 +8.4%

On a 4-sockets Intel-Skylake machine:

   compiler          base        head
  gcc-4.4.7      13162890    13508193 +2.6%
  gcc-4.9.4      14997463    15484353 +3.2%
  gcc-5.4.1      14708711    15449805 +5.0%
  gcc-6.2.0      14574099    15349204 +5.3%

The above 4 compilers are used because I've done the tests through
Intel's Linux Kernel Performance(LKP) infrastructure and they are the
available compilers there.

The benefit being less on 4 sockets machine is due to the lock
contention there(perf-profile/native_queued_spin_lock_slowpath=81%) is
less severe than on the 2 sockets machine(85%).

What the benchmark does is: it forks nr_cpu processes and then each
process does the following:
    1 mmap() 128M anonymous space;
    2 writes to each page there to trigger actual page allocation;
    3 munmap() it.
in a loop.

  https://github.com/antonblanchard/will-it-scale/blob/master/tests/page_fault1.c

Binary size wise, I have locally built them with different compilers:

[aaron@aaronlu obj]$ size */*/mm/page_alloc.o
   text    data     bss     dec     hex filename
  37409    9904    8524   55837    da1d gcc-4.9.4/base/mm/page_alloc.o
  38273    9904    8524   56701    dd7d gcc-4.9.4/head/mm/page_alloc.o
  37465    9840    8428   55733    d9b5 gcc-5.5.0/base/mm/page_alloc.o
  38169    9840    8428   56437    dc75 gcc-5.5.0/head/mm/page_alloc.o
  37573    9840    8428   55841    da21 gcc-6.4.0/base/mm/page_alloc.o
  38261    9840    8428   56529    dcd1 gcc-6.4.0/head/mm/page_alloc.o
  36863    9840    8428   55131    d75b gcc-7.2.0/base/mm/page_alloc.o
  37711    9840    8428   55979    daab gcc-7.2.0/head/mm/page_alloc.o

Text size increased about 800 bytes for mm/page_alloc.o.

[aaron@aaronlu obj]$ size */*/vmlinux
   text    data     bss     dec       hex     filename
10342757   5903208 17723392 33969357  20654cd gcc-4.9.4/base/vmlinux
10342757   5903208 17723392 33969357  20654cd gcc-4.9.4/head/vmlinux
10332448   5836608 17715200 33884256  2050860 gcc-5.5.0/base/vmlinux
10332448   5836608 17715200 33884256  2050860 gcc-5.5.0/head/vmlinux
10094546   5836696 17715200 33646442  201676a gcc-6.4.0/base/vmlinux
10094546   5836696 17715200 33646442  201676a gcc-6.4.0/head/vmlinux
10018775   5828732 17715200 33562707  2002053 gcc-7.2.0/base/vmlinux
10018775   5828732 17715200 33562707  2002053 gcc-7.2.0/head/vmlinux

Text size for vmlinux has no change though, probably due to function
alignment.

Link: http://lkml.kernel.org/r/20171013063111.GA26032@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Kemi Wang <kemi.wang@intel.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:05 -08:00
Pavel Tatashin f7f99100d8 mm: stop zeroing memory during allocation in vmemmap
vmemmap_alloc_block() will no longer zero the block, so zero memory at
its call sites for everything except struct pages.  Struct page memory
is zero'd by struct page initialization.

Replace allocators in sparse-vmemmap to use the non-zeroing version.
So, we will get the performance improvement by zeroing the memory in
parallel when struct pages are zeroed.

Add struct page zeroing as a part of initialization of other fields in
__init_single_page().

This single thread performance collected on: Intel(R) Xeon(R) CPU E7-8895
v3 @ 2.60GHz with 1T of memory (268400646 pages in 8 nodes):

                         BASE            FIX
sparse_init     11.244671836s   0.007199623s
zone_sizes_init  4.879775891s   8.355182299s
                  --------------------------
Total           16.124447727s   8.362381922s

sparse_init is where memory for struct pages is zeroed, and the zeroing
part is moved later in this patch into __init_single_page(), which is
called from zone_sizes_init().

[akpm@linux-foundation.org: make vmemmap_alloc_block_zero() private to sparse-vmemmap.c]
Link: http://lkml.kernel.org/r/20171013173214.27300-10-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Tested-by: Bob Picco <bob.picco@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:05 -08:00
Pavel Tatashin a4a3ede213 mm: zero reserved and unavailable struct pages
Some memory is reserved but unavailable: not present in memblock.memory
(because not backed by physical pages), but present in memblock.reserved.
Such memory has backing struct pages, but they are not initialized by
going through __init_single_page().

In some cases these struct pages are accessed even if they do not
contain any data.  One example is page_to_pfn() might access page->flags
if this is where section information is stored (CONFIG_SPARSEMEM,
SECTION_IN_PAGE_FLAGS).

One example of such memory: trim_low_memory_range() unconditionally
reserves from pfn 0, but e820__memblock_setup() might provide the
exiting memory from pfn 1 (i.e.  KVM).

Since struct pages are zeroed in __init_single_page(), and not during
allocation time, we must zero such struct pages explicitly.

The patch involves adding a new memblock iterator:
	for_each_resv_unavail_range(i, p_start, p_end)

Which iterates through reserved && !memory lists, and we zero struct pages
explicitly by calling mm_zero_struct_page().

===

Here is more detailed example of problem that this patch is addressing:

Run tested on qemu with the following arguments:

	-enable-kvm -cpu kvm64 -m 512 -smp 2

This patch reports that there are 98 unavailable pages.

They are: pfn 0 and pfns in range [159, 255].

Note, trim_low_memory_range() reserves only pfns in range [0, 15], it does
not reserve [159, 255] ones.

e820__memblock_setup() reports linux that the following physical ranges are
available:
    [1 , 158]
[256, 130783]

Notice, that exactly unavailable pfns are missing!

Now, lets check what we have in zone 0: [1, 131039]

pfn 0, is not part of the zone, but pfns [1, 158], are.

However, the bigger problem we have if we do not initialize these struct
pages is with memory hotplug.  Because, that path operates at 2M
boundaries (section_nr).  And checks if 2M range of pages is hot
removable.  It starts with first pfn from zone, rounds it down to 2M
boundary (sturct pages are allocated at 2M boundaries when vmemmap is
created), and checks if that section is hot removable.  In this case
start with pfn 1 and convert it down to pfn 0.  Later pfn is converted
to struct page, and some fields are checked.  Now, if we do not zero
struct pages, we get unpredictable results.

In fact when CONFIG_VM_DEBUG is enabled, and we explicitly set all
vmemmap memory to ones, the following panic is observed with kernel test
without this patch applied:

  BUG: unable to handle kernel NULL pointer dereference at          (null)
  IP: is_pageblock_removable_nolock+0x35/0x90
  PGD 0 P4D 0
  Oops: 0000 [#1] PREEMPT
  ...
  task: ffff88001f4e2900 task.stack: ffffc90000314000
  RIP: 0010:is_pageblock_removable_nolock+0x35/0x90
  Call Trace:
   ? is_mem_section_removable+0x5a/0xd0
   show_mem_removable+0x6b/0xa0
   dev_attr_show+0x1b/0x50
   sysfs_kf_seq_show+0xa1/0x100
   kernfs_seq_show+0x22/0x30
   seq_read+0x1ac/0x3a0
   kernfs_fop_read+0x36/0x190
   ? security_file_permission+0x90/0xb0
   __vfs_read+0x16/0x30
   vfs_read+0x81/0x130
   SyS_read+0x44/0xa0
   entry_SYSCALL_64_fastpath+0x1f/0xbd

Link: http://lkml.kernel.org/r/20171013173214.27300-7-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Tested-by: Bob Picco <bob.picco@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:05 -08:00
Pavel Tatashin ea1f5f3712 mm: define memblock_virt_alloc_try_nid_raw
* A new variant of memblock_virt_alloc_* allocations:
memblock_virt_alloc_try_nid_raw()
    - Does not zero the allocated memory
    - Does not panic if request cannot be satisfied

* optimize early system hash allocations

Clients can call alloc_large_system_hash() with flag: HASH_ZERO to
specify that memory that was allocated for system hash needs to be
zeroed, otherwise the memory does not need to be zeroed, and client will
initialize it.

If memory does not need to be zero'd, call the new
memblock_virt_alloc_raw() interface, and thus improve the boot
performance.

* debug for raw alloctor

When CONFIG_DEBUG_VM is enabled, this patch sets all the memory that is
returned by memblock_virt_alloc_try_nid_raw() to ones to ensure that no
places excpect zeroed memory.

Link: http://lkml.kernel.org/r/20171013173214.27300-6-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Tested-by: Bob Picco <bob.picco@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:05 -08:00
Pavel Tatashin 2f47a91f4d mm: deferred_init_memmap improvements
Patch series "complete deferred page initialization", v12.

SMP machines can benefit from the DEFERRED_STRUCT_PAGE_INIT config
option, which defers initializing struct pages until all cpus have been
started so it can be done in parallel.

However, this feature is sub-optimal, because the deferred page
initialization code expects that the struct pages have already been
zeroed, and the zeroing is done early in boot with a single thread only.
Also, we access that memory and set flags before struct pages are
initialized.  All of this is fixed in this patchset.

In this work we do the following:
 - Never read access struct page until it was initialized
 - Never set any fields in struct pages before they are initialized
 - Zero struct page at the beginning of struct page initialization

==========================================================================
Performance improvements on x86 machine with 8 nodes:
Intel(R) Xeon(R) CPU E7-8895 v3 @ 2.60GHz and 1T of memory:
                        TIME          SPEED UP
base no deferred:       95.796233s
fix no deferred:        79.978956s    19.77%

base deferred:          77.254713s
fix deferred:           55.050509s    40.34%
==========================================================================
SPARC M6 3600 MHz with 15T of memory
                        TIME          SPEED UP
base no deferred:       358.335727s
fix no deferred:        302.320936s   18.52%

base deferred:          237.534603s
fix deferred:           182.103003s   30.44%
==========================================================================
Raw dmesg output with timestamps:
x86 base no deferred:    https://hastebin.com/ofunepurit.scala
x86 base deferred:       https://hastebin.com/ifazegeyas.scala
x86 fix no deferred:     https://hastebin.com/pegocohevo.scala
x86 fix deferred:        https://hastebin.com/ofupevikuk.scala
sparc base no deferred:  https://hastebin.com/ibobeteken.go
sparc base deferred:     https://hastebin.com/fariqimiyu.go
sparc fix no deferred:   https://hastebin.com/muhegoheyi.go
sparc fix deferred:      https://hastebin.com/xadinobutu.go

This patch (of 11):

deferred_init_memmap() is called when struct pages are initialized later
in boot by slave CPUs.  This patch simplifies and optimizes this
function, and also fixes a couple issues (described below).

The main change is that now we are iterating through free memblock areas
instead of all configured memory.  Thus, we do not have to check if the
struct page has already been initialized.

=====
In deferred_init_memmap() where all deferred struct pages are
initialized we have a check like this:

  if (page->flags) {
	VM_BUG_ON(page_zone(page) != zone);
	goto free_range;
  }

This way we are checking if the current deferred page has already been
initialized.  It works, because memory for struct pages has been zeroed,
and the only way flags are not zero if it went through
__init_single_page() before.  But, once we change the current behavior
and won't zero the memory in memblock allocator, we cannot trust
anything inside "struct page"es until they are initialized.  This patch
fixes this.

The deferred_init_memmap() is re-written to loop through only free
memory ranges provided by memblock.

Note, this first issue is relevant only when the following change is
merged:

=====
This patch fixes another existing issue on systems that have holes in
zones i.e CONFIG_HOLES_IN_ZONE is defined.

In for_each_mem_pfn_range() we have code like this:

  if (!pfn_valid_within(pfn)
	goto free_range;

Note: 'page' is not set to NULL and is not incremented but 'pfn'
advances.  Thus means if deferred struct pages are enabled on systems
with these kind of holes, linux would get memory corruptions.  I have
fixed this issue by defining a new macro that performs all the necessary
operations when we free the current set of pages.

[pasha.tatashin@oracle.com: buddy page accessed before initialized]
  Link: http://lkml.kernel.org/r/20171102170221.7401-2-pasha.tatashin@oracle.com
Link: http://lkml.kernel.org/r/20171013173214.27300-2-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Tested-by: Bob Picco <bob.picco@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:05 -08:00
Levin, Alexander (Sasha Levin) 4950276672 kmemcheck: remove annotations
Patch series "kmemcheck: kill kmemcheck", v2.

As discussed at LSF/MM, kill kmemcheck.

KASan is a replacement that is able to work without the limitation of
kmemcheck (single CPU, slow).  KASan is already upstream.

We are also not aware of any users of kmemcheck (or users who don't
consider KASan as a suitable replacement).

The only objection was that since KASAN wasn't supported by all GCC
versions provided by distros at that time we should hold off for 2
years, and try again.

Now that 2 years have passed, and all distros provide gcc that supports
KASAN, kill kmemcheck again for the very same reasons.

This patch (of 4):

Remove kmemcheck annotations, and calls to kmemcheck from the kernel.

[alexander.levin@verizon.com: correctly remove kmemcheck call from dma_map_sg_attrs]
  Link: http://lkml.kernel.org/r/20171012192151.26531-1-alexander.levin@verizon.com
Link: http://lkml.kernel.org/r/20171007030159.22241-2-alexander.levin@verizon.com
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tim Hansen <devtimhansen@gmail.com>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:04 -08:00
Michal Hocko d7ab3672c3 mm, page_alloc: fail has_unmovable_pages when seeing reserved pages
Reserved pages should be completely ignored by the core mm because they
have a special meaning for their owners.  has_unmovable_pages doesn't
check those so we rely on other tests (reference count, or PageLRU) to
fail on such pages.  Althought this happens to work it is safer to
simply check for those explicitly and do not rely on the owner of the
page to abuse those fields for special purposes.

Please note that this is more of a further fortification of the code
rahter than a fix of an existing issue.

Link: http://lkml.kernel.org/r/20171013120756.jeopthigbmm3c7bl@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:02 -08:00
Michal Hocko 4da2ce250f mm: distinguish CMA and MOVABLE isolation in has_unmovable_pages()
Joonsoo has noticed that "mm: drop migrate type checks from
has_unmovable_pages" would break CMA allocator because it relies on
has_unmovable_pages returning false even for CMA pageblocks which in
fact don't have to be movable:

 alloc_contig_range
   start_isolate_page_range
     set_migratetype_isolate
       has_unmovable_pages

This is a result of the code sharing between CMA and memory hotplug
while each one has a different idea of what has_unmovable_pages should
return.  This is unfortunate but fixing it properly would require a lot
of code duplication.

Fix the issue by introducing the requested migrate type argument and
special case MIGRATE_CMA case where CMA page blocks are handled
properly.  This will work for memory hotplug because it requires
MIGRATE_MOVABLE.

Link: http://lkml.kernel.org/r/20171019122118.y6cndierwl2vnguj@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Ran Wang <ran.wang_1@nxp.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:02 -08:00
Michal Hocko d7b236e10c mm: drop migrate type checks from has_unmovable_pages
Michael has noticed that the memory offline tries to migrate kernel code
pages when doing

 echo 0 > /sys/devices/system/memory/memory0/online

The current implementation will fail the operation after several failed
page migration attempts but we shouldn't even attempt to migrate that
memory and fail right away because this memory is clearly not
migrateable.  This will become a real problem when we drop the retry
loop counter resp.  timeout.

The real problem is in has_unmovable_pages in fact.  We should fail if
there are any non migrateable pages in the area.  In orther to guarantee
that remove the migrate type checks because MIGRATE_MOVABLE is not
guaranteed to contain only migrateable pages.  It is merely a heuristic.
Similarly MIGRATE_CMA does guarantee that the page allocator doesn't
allocate any non-migrateable pages from the block but CMA allocations
themselves are unlikely to migrateable.  Therefore remove both checks.

[akpm@linux-foundation.org: remove unused local `mt']
Link: http://lkml.kernel.org/r/20171013120013.698-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ran Wang <ran.wang_1@nxp.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:02 -08:00
Michal Hocko 9b6e63cbf8 mm, page_alloc: add scheduling point to memmap_init_zone
memmap_init_zone gets a pfn range to initialize and it can be really
large resulting in a soft lockup on non-preemptible kernels

  NMI watchdog: BUG: soft lockup - CPU#31 stuck for 23s! [kworker/u642:5:1720]
  [...]
  task: ffff88ecd7e902c0 ti: ffff88eca4e50000 task.ti: ffff88eca4e50000
  RIP: move_pfn_range_to_zone+0x185/0x1d0
  [...]
  Call Trace:
    devm_memremap_pages+0x2c7/0x430
    pmem_attach_disk+0x2fd/0x3f0 [nd_pmem]
    nvdimm_bus_probe+0x64/0x110 [libnvdimm]
    driver_probe_device+0x1f7/0x420
    bus_for_each_drv+0x52/0x80
    __device_attach+0xb0/0x130
    bus_probe_device+0x87/0xa0
    device_add+0x3fc/0x5f0
    nd_async_device_register+0xe/0x40 [libnvdimm]
    async_run_entry_fn+0x43/0x150
    process_one_work+0x14e/0x410
    worker_thread+0x116/0x490
    kthread+0xc7/0xe0
    ret_from_fork+0x3f/0x70

Fix this by adding a scheduling point once per page block.

Link: http://lkml.kernel.org/r/20170918121410.24466-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Dan Williams <dan.j.williams@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Arnd Bergmann 57148a64e8 mm: meminit: mark init_reserved_page as __meminit
The function is called from __meminit context and calls other __meminit
functions but isn't it self mark as such today:

  WARNING: vmlinux.o(.text.unlikely+0x4516): Section mismatch in reference from the function init_reserved_page() to the function .meminit.text:early_pfn_to_nid()
  The function init_reserved_page() references the function __meminit early_pfn_to_nid().
  This is often because init_reserved_page lacks a __meminit annotation or the annotation of early_pfn_to_nid is wrong.

On most compilers, we don't notice this because the function gets
inlined all the time.  Adding __meminit here fixes the harmless warning
for the old versions and is generally the correct annotation.

Link: http://lkml.kernel.org/r/20170915193149.901180-1-arnd@arndb.de
Fixes: 7e18adb4f8 ("mm: meminit: initialise remaining struct pages in parallel with kswapd")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:24 -07:00
Tetsuo Handa f19360f015 mm/page_alloc.c: apply gfp_allowed_mask before the first allocation attempt
We are by error initializing alloc_flags before gfp_allowed_mask is
applied.  This could cause problems after pm_restrict_gfp_mask() is called
during suspend operation.  Apply gfp_allowed_mask before initializing
alloc_flags so that the first allocation attempt uses correct flags.

Link: http://lkml.kernel.org/r/201709020016.ADJ21342.OFLJHOOSMFVtFQ@I-love.SAKURA.ne.jp
Fixes: 83d4ca8148 ("mm, page_alloc: move __GFP_HARDWALL modifications out of the fastpath")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:47 -07:00
Kemi Wang 3a321d2a3d mm: change the call sites of numa statistics items
Patch series "Separate NUMA statistics from zone statistics", v2.

Each page allocation updates a set of per-zone statistics with a call to
zone_statistics().  As discussed in 2017 MM summit, these are a
substantial source of overhead in the page allocator and are very rarely
consumed.  This significant overhead in cache bouncing caused by zone
counters (NUMA associated counters) update in parallel in multi-threaded
page allocation (pointed out by Dave Hansen).

A link to the MM summit slides:
  http://people.netfilter.org/hawk/presentations/MM-summit2017/MM-summit2017-JesperBrouer.pdf

To mitigate this overhead, this patchset separates NUMA statistics from
zone statistics framework, and update NUMA counter threshold to a fixed
size of MAX_U16 - 2, as a small threshold greatly increases the update
frequency of the global counter from local per cpu counter (suggested by
Ying Huang).  The rationality is that these statistics counters don't
need to be read often, unlike other VM counters, so it's not a problem
to use a large threshold and make readers more expensive.

With this patchset, we see 31.3% drop of CPU cycles(537-->369, see
below) for per single page allocation and reclaim on Jesper's
page_bench03 benchmark.  Meanwhile, this patchset keeps the same style
of virtual memory statistics with little end-user-visible effects (only
move the numa stats to show behind zone page stats, see the first patch
for details).

I did an experiment of single page allocation and reclaim concurrently
using Jesper's page_bench03 benchmark on a 2-Socket Broadwell-based
server (88 processors with 126G memory) with different size of threshold
of pcp counter.

Benchmark provided by Jesper D Brouer(increase loop times to 10000000):
  https://github.com/netoptimizer/prototype-kernel/tree/master/kernel/mm/bench

   Threshold   CPU cycles    Throughput(88 threads)
      32        799         241760478
      64        640         301628829
      125       537         358906028 <==> system by default
      256       468         412397590
      512       428         450550704
      4096      399         482520943
      20000     394         489009617
      30000     395         488017817
      65533     369(-31.3%) 521661345(+45.3%) <==> with this patchset
      N/A       342(-36.3%) 562900157(+56.8%) <==> disable zone_statistics

This patch (of 3):

In this patch, NUMA statistics is separated from zone statistics
framework, all the call sites of NUMA stats are changed to use
numa-stats-specific functions, it does not have any functionality change
except that the number of NUMA stats is shown behind zone page stats
when users *read* the zone info.

E.g. cat /proc/zoneinfo
    ***Base***                           ***With this patch***
nr_free_pages 3976                         nr_free_pages 3976
nr_zone_inactive_anon 0                    nr_zone_inactive_anon 0
nr_zone_active_anon 0                      nr_zone_active_anon 0
nr_zone_inactive_file 0                    nr_zone_inactive_file 0
nr_zone_active_file 0                      nr_zone_active_file 0
nr_zone_unevictable 0                      nr_zone_unevictable 0
nr_zone_write_pending 0                    nr_zone_write_pending 0
nr_mlock     0                             nr_mlock     0
nr_page_table_pages 0                      nr_page_table_pages 0
nr_kernel_stack 0                          nr_kernel_stack 0
nr_bounce    0                             nr_bounce    0
nr_zspages   0                             nr_zspages   0
numa_hit 0                                *nr_free_cma  0*
numa_miss 0                                numa_hit     0
numa_foreign 0                             numa_miss    0
numa_interleave 0                          numa_foreign 0
numa_local   0                             numa_interleave 0
numa_other   0                             numa_local   0
*nr_free_cma 0*                            numa_other 0
    ...                                        ...
vm stats threshold: 10                     vm stats threshold: 10
    ...                                        ...

The next patch updates the numa stats counter size and threshold.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1503568801-21305-2-git-send-email-kemi.wang@intel.com
Signed-off-by: Kemi Wang <kemi.wang@intel.com>
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Ying Huang <ying.huang@intel.com>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:47 -07:00
Michal Hocko cd04ae1e2d mm, oom: do not rely on TIF_MEMDIE for memory reserves access
For ages we have been relying on TIF_MEMDIE thread flag to mark OOM
victims and then, among other things, to give these threads full access
to memory reserves.  There are few shortcomings of this implementation,
though.

First of all and the most serious one is that the full access to memory
reserves is quite dangerous because we leave no safety room for the
system to operate and potentially do last emergency steps to move on.

Secondly this flag is per task_struct while the OOM killer operates on
mm_struct granularity so all processes sharing the given mm are killed.
Giving the full access to all these task_structs could lead to a quick
memory reserves depletion.  We have tried to reduce this risk by giving
TIF_MEMDIE only to the main thread and the currently allocating task but
that doesn't really solve this problem while it surely opens up a room
for corner cases - e.g.  GFP_NO{FS,IO} requests might loop inside the
allocator without access to memory reserves because a particular thread
was not the group leader.

Now that we have the oom reaper and that all oom victims are reapable
after 1b51e65eab ("oom, oom_reaper: allow to reap mm shared by the
kthreads") we can be more conservative and grant only partial access to
memory reserves because there are reasonable chances of the parallel
memory freeing.  We still want some access to reserves because we do not
want other consumers to eat up the victim's freed memory.  oom victims
will still contend with __GFP_HIGH users but those shouldn't be so
aggressive to starve oom victims completely.

Introduce ALLOC_OOM flag and give all tsk_is_oom_victim tasks access to
the half of the reserves.  This makes the access to reserves independent
on which task has passed through mark_oom_victim.  Also drop any usage
of TIF_MEMDIE from the page allocator proper and replace it by
tsk_is_oom_victim as well which will make page_alloc.c completely
TIF_MEMDIE free finally.

CONFIG_MMU=n doesn't have oom reaper so let's stick to the original
ALLOC_NO_WATERMARKS approach.

There is a demand to make the oom killer memcg aware which will imply
many tasks killed at once.  This change will allow such a usecase
without worrying about complete memory reserves depletion.

Link: http://lkml.kernel.org/r/20170810075019.28998-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-06 17:27:30 -07:00
Michal Hocko c41f012ade mm: rename global_page_state to global_zone_page_state
global_page_state is error prone as a recent bug report pointed out [1].
It only returns proper values for zone based counters as the enum it
gets suggests.  We already have global_node_page_state so let's rename
global_page_state to global_zone_page_state to be more explicit here.
All existing users seems to be correct:

$ git grep "global_page_state(NR_" | sed 's@.*(\(NR_[A-Z_]*\)).*@\1@' | sort | uniq -c
      2 NR_BOUNCE
      2 NR_FREE_CMA_PAGES
     11 NR_FREE_PAGES
      1 NR_KERNEL_STACK_KB
      1 NR_MLOCK
      2 NR_PAGETABLE

This patch shouldn't introduce any functional change.

[1] http://lkml.kernel.org/r/201707260628.v6Q6SmaS030814@www262.sakura.ne.jp

Link: http://lkml.kernel.org/r/20170801134256.5400-2-hannes@cmpxchg.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-06 17:27:29 -07:00