Unify alloc_misplaced_dst_page() and alloc_misplaced_dst_page_thp().
Removes an assumption that compound pages are HPAGE_PMD_ORDER.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
This removes an assumption that a large folio is HPAGE_PMD_ORDER
as well as letting us remove the call to prep_transhuge_page()
and a few hidden calls to compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
The access to mlock_pvec is protected by disabling preemption via
get_cpu_var() or implicit by having preemption disabled by the caller
(in mlock_page_drain() case). This breaks on PREEMPT_RT since
folio_lruvec_lock_irq() acquires a sleeping lock in this section.
Create struct mlock_pvec which consits of the local_lock_t and the
pagevec. Acquire the local_lock() before accessing the per-CPU pagevec.
Replace mlock_page_drain() with a _local() version which is invoked on
the local CPU and acquires the local_lock_t and a _remote() version
which uses the pagevec from a remote CPU which offline.
Link: https://lkml.kernel.org/r/YjizWi9IY0mpvIfb@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.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>
This adds two trace events for base page and HugeTLB page migrations.
These events, closely follow the implementation details like setting and
removing of PTE migration entries, which are essential operations for
migration. The new CREATE_TRACE_POINTS in <mm/rmap.c> covers both
<events/migration.h> and <events/tlb.h> based trace events. Hence drop
redundant CREATE_TRACE_POINTS from other places which could have otherwise
conflicted during build.
Link: https://lkml.kernel.org/r/1643368182-9588-3-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Rewrite how munlock works to massively reduce the contention
on i_mmap_rwsem (Hugh Dickins):
https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/
- Sort out the page refcount mess for ZONE_DEVICE pages (Christoph Hellwig):
https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/
- Convert GUP to use folios and make pincount available for order-1
pages. (Matthew Wilcox)
- Convert a few more truncation functions to use folios (Matthew Wilcox)
- Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew Wilcox)
- Convert rmap_walk to use folios (Matthew Wilcox)
- Convert most of shrink_page_list() to use a folio (Matthew Wilcox)
- Add support for creating large folios in readahead (Matthew Wilcox)
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Merge tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache
Pull folio updates from Matthew Wilcox:
- Rewrite how munlock works to massively reduce the contention on
i_mmap_rwsem (Hugh Dickins):
https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/
- Sort out the page refcount mess for ZONE_DEVICE pages (Christoph
Hellwig):
https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/
- Convert GUP to use folios and make pincount available for order-1
pages. (Matthew Wilcox)
- Convert a few more truncation functions to use folios (Matthew
Wilcox)
- Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew
Wilcox)
- Convert rmap_walk to use folios (Matthew Wilcox)
- Convert most of shrink_page_list() to use a folio (Matthew Wilcox)
- Add support for creating large folios in readahead (Matthew Wilcox)
* tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache: (114 commits)
mm/damon: minor cleanup for damon_pa_young
selftests/vm/transhuge-stress: Support file-backed PMD folios
mm/filemap: Support VM_HUGEPAGE for file mappings
mm/readahead: Switch to page_cache_ra_order
mm/readahead: Align file mappings for non-DAX
mm/readahead: Add large folio readahead
mm: Support arbitrary THP sizes
mm: Make large folios depend on THP
mm: Fix READ_ONLY_THP warning
mm/filemap: Allow large folios to be added to the page cache
mm: Turn can_split_huge_page() into can_split_folio()
mm/vmscan: Convert pageout() to take a folio
mm/vmscan: Turn page_check_references() into folio_check_references()
mm/vmscan: Account large folios correctly
mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios
mm/vmscan: Free non-shmem folios without splitting them
mm/rmap: Constify the rmap_walk_control argument
mm/rmap: Convert rmap_walk() to take a folio
mm: Turn page_anon_vma() into folio_anon_vma()
mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read()
...
Abhishek reported that after patch [1], hotplug operations are taking
roughly double the expected time. [2]
The reason behind is that the CPU callbacks that
migrate_on_reclaim_init() sets always call set_migration_target_nodes()
whenever a CPU is brought up/down.
But we only care about numa nodes going from having cpus to become
cpuless, and vice versa, as that influences the demotion_target order.
We do already have two CPU callbacks (vmstat_cpu_online() and
vmstat_cpu_dead()) that check exactly that, so get rid of the CPU
callbacks in migrate_on_reclaim_init() and only call
set_migration_target_nodes() from vmstat_cpu_{dead,online}() whenever a
numa node change its N_CPU state.
[1] https://lore.kernel.org/linux-mm/20210721063926.3024591-2-ying.huang@intel.com/
[2] https://lore.kernel.org/linux-mm/eb438ddd-2919-73d4-bd9f-b7eecdd9577a@linux.vnet.ibm.com/
[osalvador@suse.de: add feedback from Huang Ying]
Link: https://lkml.kernel.org/r/20220314150945.12694-1-osalvador@suse.de
Link: https://lkml.kernel.org/r/20220310120749.23077-1-osalvador@suse.de
Fixes: 884a6e5d1f ("mm/migrate: update node demotion order on hotplug events")
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reported-by: Abhishek Goel <huntbag@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Abhishek Goel <huntbag@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>
With the advent of various new memory types, some machines will have
multiple types of memory, e.g. DRAM and PMEM (persistent memory). The
memory subsystem of these machines can be called memory tiering system,
because the performance of the different types of memory are usually
different.
In such system, because of the memory accessing pattern changing etc,
some pages in the slow memory may become hot globally. So in this
patch, the NUMA balancing mechanism is enhanced to optimize the page
placement among the different memory types according to hot/cold
dynamically.
In a typical memory tiering system, there are CPUs, fast memory and slow
memory in each physical NUMA node. The CPUs and the fast memory will be
put in one logical node (called fast memory node), while the slow memory
will be put in another (faked) logical node (called slow memory node).
That is, the fast memory is regarded as local while the slow memory is
regarded as remote. So it's possible for the recently accessed pages in
the slow memory node to be promoted to the fast memory node via the
existing NUMA balancing mechanism.
The original NUMA balancing mechanism will stop to migrate pages if the
free memory of the target node becomes below the high watermark. This
is a reasonable policy if there's only one memory type. But this makes
the original NUMA balancing mechanism almost do not work to optimize
page placement among different memory types. Details are as follows.
It's the common cases that the working-set size of the workload is
larger than the size of the fast memory nodes. Otherwise, it's
unnecessary to use the slow memory at all. So, there are almost always
no enough free pages in the fast memory nodes, so that the globally hot
pages in the slow memory node cannot be promoted to the fast memory
node. To solve the issue, we have 2 choices as follows,
a. Ignore the free pages watermark checking when promoting hot pages
from the slow memory node to the fast memory node. This will
create some memory pressure in the fast memory node, thus trigger
the memory reclaiming. So that, the cold pages in the fast memory
node will be demoted to the slow memory node.
b. Define a new watermark called wmark_promo which is higher than
wmark_high, and have kswapd reclaiming pages until free pages reach
such watermark. The scenario is as follows: when we want to promote
hot-pages from a slow memory to a fast memory, but fast memory's free
pages would go lower than high watermark with such promotion, we wake
up kswapd with wmark_promo watermark in order to demote cold pages and
free us up some space. So, next time we want to promote hot-pages we
might have a chance of doing so.
The choice "a" may create high memory pressure in the fast memory node.
If the memory pressure of the workload is high, the memory pressure
may become so high that the memory allocation latency of the workload
is influenced, e.g. the direct reclaiming may be triggered.
The choice "b" works much better at this aspect. If the memory
pressure of the workload is high, the hot pages promotion will stop
earlier because its allocation watermark is higher than that of the
normal memory allocation. So in this patch, choice "b" is implemented.
A new zone watermark (WMARK_PROMO) is added. Which is larger than the
high watermark and can be controlled via watermark_scale_factor.
In addition to the original page placement optimization among sockets,
the NUMA balancing mechanism is extended to be used to optimize page
placement according to hot/cold among different memory types. So the
sysctl user space interface (numa_balancing) is extended in a backward
compatible way as follow, so that the users can enable/disable these
functionality individually.
The sysctl is converted from a Boolean value to a bits field. The
definition of the flags is,
- 0: NUMA_BALANCING_DISABLED
- 1: NUMA_BALANCING_NORMAL
- 2: NUMA_BALANCING_MEMORY_TIERING
We have tested the patch with the pmbench memory accessing benchmark
with the 80:20 read/write ratio and the Gauss access address
distribution on a 2 socket Intel server with Optane DC Persistent
Memory Model. The test results shows that the pmbench score can
improve up to 95.9%.
Thanks Andrew Morton to help fix the document format error.
Link: https://lkml.kernel.org/r/20220221084529.1052339-3-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: zhongjiang-ali <zhongjiang-ali@linux.alibaba.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Feng Tang <feng.tang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "NUMA balancing: optimize memory placement for memory tiering system", v13
With the advent of various new memory types, some machines will have
multiple types of memory, e.g. DRAM and PMEM (persistent memory). The
memory subsystem of these machines can be called memory tiering system,
because the performance of the different types of memory are different.
After commit c221c0b030 ("device-dax: "Hotplug" persistent memory for
use like normal RAM"), the PMEM could be used as the cost-effective
volatile memory in separate NUMA nodes. In a typical memory tiering
system, there are CPUs, DRAM and PMEM in each physical NUMA node. The
CPUs and the DRAM will be put in one logical node, while the PMEM will
be put in another (faked) logical node.
To optimize the system overall performance, the hot pages should be
placed in DRAM node. To do that, we need to identify the hot pages in
the PMEM node and migrate them to DRAM node via NUMA migration.
In the original NUMA balancing, there are already a set of existing
mechanisms to identify the pages recently accessed by the CPUs in a node
and migrate the pages to the node. So we can reuse these mechanisms to
build the mechanisms to optimize the page placement in the memory
tiering system. This is implemented in this patchset.
At the other hand, the cold pages should be placed in PMEM node. So, we
also need to identify the cold pages in the DRAM node and migrate them
to PMEM node.
In commit 26aa2d199d ("mm/migrate: demote pages during reclaim"), a
mechanism to demote the cold DRAM pages to PMEM node under memory
pressure is implemented. Based on that, the cold DRAM pages can be
demoted to PMEM node proactively to free some memory space on DRAM node
to accommodate the promoted hot PMEM pages. This is implemented in this
patchset too.
We have tested the solution with the pmbench memory accessing benchmark
with the 80:20 read/write ratio and the Gauss access address
distribution on a 2 socket Intel server with Optane DC Persistent Memory
Model. The test results shows that the pmbench score can improve up to
95.9%.
This patch (of 3):
In a system with multiple memory types, e.g. DRAM and PMEM, the CPU
and DRAM in one socket will be put in one NUMA node as before, while
the PMEM will be put in another NUMA node as described in the
description of the commit c221c0b030 ("device-dax: "Hotplug"
persistent memory for use like normal RAM"). So, the NUMA balancing
mechanism will identify all PMEM accesses as remote access and try to
promote the PMEM pages to DRAM.
To distinguish the number of the inter-type promoted pages from that of
the inter-socket migrated pages. A new vmstat count is added. The
counter is per-node (count in the target node). So this can be used to
identify promotion imbalance among the NUMA nodes.
Link: https://lkml.kernel.org/r/20220301085329.3210428-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20220221084529.1052339-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20220221084529.1052339-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: zhongjiang-ali <zhongjiang-ali@linux.alibaba.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When memory is tight, system may start to compact memory for large
continuous memory demands. If one process tries to lock a memory page
that is being locked and isolated for compaction, it may wait a long time
or even forever. This is because compaction will perform non-atomic
PG_Isolated clear while holding page lock, this may overwrite PG_waiters
set by the process that can't obtain the page lock and add itself to the
waiting queue to wait for the lock to be unlocked.
CPU1 CPU2
lock_page(page); (successful)
lock_page(); (failed)
__ClearPageIsolated(page); SetPageWaiters(page) (may be overwritten)
unlock_page(page);
The solution is to not perform non-atomic operation on page flags while
holding page lock.
Link: https://lkml.kernel.org/r/20220315030515.20263-1-andrew.yang@mediatek.com
Signed-off-by: andrew.yang <andrew.yang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Vlastimil Babka" <vbabka@suse.cz>
Cc: David Howells <dhowells@redhat.com>
Cc: "William Kucharski" <william.kucharski@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Nicholas Tang <nicholas.tang@mediatek.com>
Cc: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In commit ac16ec8353 ("mm: migrate: support multiple target nodes
demotion"), after the first demotion target node is found, we will
continue to check the next candidate obtained via find_next_best_node().
This is to find all demotion target nodes with same NUMA distance. But
one side effect of find_next_best_node() is that the candidate node
returned will be set in "used" parameter, even if the candidate node isn't
passed in the following NUMA distance checking, the candidate node will
not be used as demotion target node for the following nodes. For example,
for system as follows,
node distances:
node 0 1 2 3
0: 10 21 17 28
1: 21 10 28 17
2: 17 28 10 28
3: 28 17 28 10
when we establish demotion target node for node 0, in the first round node
2 is added to the demotion target node set. Then in the second round,
node 3 is checked and failed because distance(0, 3) > distance(0, 2). But
node 3 is set in "used" nodemask too. When we establish demotion target
node for node 1, there is no available node. This is wrong, node 3 should
be set as the demotion target of node 1.
To fix this, if the candidate node is failed to pass the distance
checking, it will be cleared in "used" nodemask. So that it can be used
for the following node.
The bug can be reproduced and fixed with this patch on a 2 socket server
machine with DRAM and PMEM.
Link: https://lkml.kernel.org/r/20220128055940.1792614-1-ying.huang@intel.com
Fixes: ac16ec8353 ("mm: migrate: support multiple target nodes demotion")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Yang Shi <shy828301@gmail.com>
Cc: zhongjiang-ali <zhongjiang-ali@linux.alibaba.com>
Cc: Xunlei Pang <xlpang@linux.alibaba.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>
PF_SWAPWRITE has been redundant since v3.2 commit ee72886d8e ("mm:
vmscan: do not writeback filesystem pages in direct reclaim").
Coincidentally, NeilBrown's current patch "remove inode_congested()"
deletes may_write_to_inode(), which appeared to be the one function which
took notice of PF_SWAPWRITE. But if you study the old logic, and the
conditions under which may_write_to_inode() was called, you discover that
flag and function have been pointless for a decade.
Link: https://lkml.kernel.org/r/75e80e7-742d-e3bd-531-614db8961e4@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Jan Kara <jack@suse.de>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We can pass FOLL_GET | FOLL_DUMP to follow_page directly to simplify the
code a bit in add_page_for_migration and split_huge_pages_pid.
Link: https://lkml.kernel.org/r/20220311072002.35575-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Simplify the code by using flush_dcache_folio().
Link: https://lkml.kernel.org/r/20220210123058.79206-8-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lars Persson <lars.persson@axis.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The D-cache maintenance inside move_to_new_page() only consider one
page, there is still D-cache maintenance issue for tail pages of
compound page (e.g. THP or HugeTLB).
THP migration is only enabled on x86_64, ARM64 and powerpc, while
powerpc and arm64 need to maintain the consistency between I-Cache and
D-Cache, which depends on flush_dcache_page() to maintain the
consistency between I-Cache and D-Cache.
But there is no issues on arm64 and powerpc since they already considers
the compound page cache flushing in their icache flush function.
HugeTLB migration is enabled on arm, arm64, mips, parisc, powerpc,
riscv, s390 and sh, while arm has handled the compound page cache flush
in flush_dcache_page(), but most others do not.
In theory, the issue exists on many architectures. Fix this by not
using flush_dcache_folio() since it is not backportable.
Link: https://lkml.kernel.org/r/20220210123058.79206-3-songmuchun@bytedance.com
Fixes: 290408d4a2 ("hugetlb: hugepage migration core")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lars Persson <lars.persson@axis.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove a quirky special case from follow_pfn_pte(), and adjust its
callers to match. Caller changes include:
__get_user_pages(): Regardless of any FOLL_* flags, get_user_pages() and
its variants should handle PFN-only entries by stopping early, if the
caller expected **pages to be filled in. This makes for a more reliable
API, as compared to the previous approach of skipping over such entries
(and thus leaving them silently unwritten).
move_pages(): squash the -EEXIST error return from follow_page() into
-EFAULT, because -EFAULT is listed in the man page, whereas -EEXIST is
not.
Link: https://lkml.kernel.org/r/20220204020010.68930-3-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Peter Xu <peterx@redhat.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert the callers to pass a folio and the try_to_migrate_one()
worker to use a folio throughout. Fixes an assumption that a
folio must be <= PMD size.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
page_mapped_in_vma() really just wants to walk one page, but as the
code stands, if passed the head page of a compound page, it will
walk every page in the compound page. Extract pfn/nr_pages/pgoff
from the struct page early, so they can be overridden by
page_mapped_in_vma().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Instead of declaring a struct page_vma_mapped_walk directly,
use these helpers to allow us to transition to a PFN approach in the
following patches.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Split the code used to migrate to and from ZONE_DEVICE memory from
migrate.c into a new file.
Link: https://lkml.kernel.org/r/20220210072828.2930359-14-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: "Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christian Knig <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Make the flow a little more clear and prepare for adding a new
ZONE_DEVICE memory type.
Link: https://lkml.kernel.org/r/20220210072828.2930359-13-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Tested-by: "Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christian Knig <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Make the flow a little more clear and prepare for adding a new
ZONE_DEVICE memory type.
Link: https://lkml.kernel.org/r/20220210072828.2930359-12-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Tested-by: "Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christian Knig <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
ZONE_DEVICE struct pages have an extra reference count that complicates
the code for put_page() and several places in the kernel that need to
check the reference count to see that a page is not being used (gup,
compaction, migration, etc.). Clean up the code so the reference count
doesn't need to be treated specially for ZONE_DEVICE pages.
Note that this excludes the special idle page wakeup for fsdax pages,
which still happens at refcount 1. This is a separate issue and will
be sorted out later. Given that only fsdax pages require the
notifiacation when the refcount hits 1 now, the PAGEMAP_OPS Kconfig
symbol can go away and be replaced with a FS_DAX check for this hook
in the put_page fastpath.
Based on an earlier patch from Ralph Campbell <rcampbell@nvidia.com>.
Link: https://lkml.kernel.org/r/20220210072828.2930359-8-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Tested-by: "Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christian Knig <christian.koenig@amd.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Page migration of a VM_LOCKED page tends to fail, because when the old
page is unmapped, it is put on the mlock pagevec with raised refcount,
which then fails the freeze.
At first I thought this would be fixed by a local mlock_page_drain() at
the upper rmap_walk() level - which would have nicely batched all the
munlocks of that page; but tests show that the task can too easily move
to another cpu, leaving pagevec residue behind which fails the migration.
So try_to_migrate_one() drain the local pagevec after page_remove_rmap()
from a VM_LOCKED vma; and do the same in try_to_unmap_one(), whose
TTU_IGNORE_MLOCK users would want the same treatment; and do the same
in remove_migration_pte() - not important when successfully inserting
a new page, but necessary when hoping to retry after failure.
Any new pagevec runs the risk of adding a new way of stranding, and we
might discover other corners where mlock_page_drain() or lru_add_drain()
would now help.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Compaction, NUMA page movement, THP collapse/split, and memory failure
do isolate unevictable pages from their "LRU", losing the record of
mlock_count in doing so (isolators are likely to use page->lru for their
own private lists, so mlock_count has to be presumed lost).
That's unfortunate, and we should put in some work to correct that: one
can imagine a function to build up the mlock_count again - but it would
require i_mmap_rwsem for read, so be careful where it's called. Or
page_referenced_one() and try_to_unmap_one() might do that extra work.
But one place that can very easily be improved is page migration's
__unmap_and_move(): a small adjustment to where the successful new page
is put back on LRU, and its mlock_count (if any) is built back up by
remove_migration_ptes().
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Add vma argument to mlock_vma_page() and munlock_vma_page(), make them
inline functions which check (vma->vm_flags & VM_LOCKED) before calling
mlock_page() and munlock_page() in mm/mlock.c.
Add bool compound to mlock_vma_page() and munlock_vma_page(): this is
because we have understandable difficulty in accounting pte maps of THPs,
and if passed a PageHead page, mlock_page() and munlock_page() cannot
tell whether it's a pmd map to be counted or a pte map to be ignored.
Add vma arg to page_add_file_rmap() and page_remove_rmap(), like the
others, and use that to call mlock_vma_page() at the end of the page
adds, and munlock_vma_page() at the end of page_remove_rmap() (end or
beginning? unimportant, but end was easier for assertions in testing).
No page lock is required (although almost all adds happen to hold it):
delete the "Serialize with page migration" BUG_ON(!PageLocked(page))s.
Certainly page lock did serialize with page migration, but I'm having
difficulty explaining why that was ever important.
Mlock accounting on THPs has been hard to define, differed between anon
and file, involved PageDoubleMap in some places and not others, required
clear_page_mlock() at some points. Keep it simple now: just count the
pmds and ignore the ptes, there is no reason for ptes to undo pmd mlocks.
page_add_new_anon_rmap() callers unchanged: they have long been calling
lru_cache_add_inactive_or_unevictable(), which does its own VM_LOCKED
handling (it also checks for not VM_SPECIAL: I think that's overcautious,
and inconsistent with other checks, that mmap_region() already prevents
VM_LOCKED on VM_SPECIAL; but haven't quite convinced myself to change it).
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
This fixes the FIXME in migrate_vma_check_page().
Before migrating a page migration code will take a reference and check
there are no unexpected page references, failing the migration if there
are. When a thread faults on a migration entry it will take a temporary
reference to the page to wait for the page to become unlocked signifying
the migration entry has been removed.
This reference is dropped just prior to waiting on the page lock,
however the extra reference can cause migration failures so it is
desirable to avoid taking it.
As migration code already has a reference to the migrating page an extra
reference to wait on PG_locked is unnecessary so long as the reference
can't be dropped whilst setting up the wait.
When faulting on a migration entry the ptl is taken to check the
migration entry. Removing a migration entry also requires the ptl, and
migration code won't drop its page reference until after the migration
entry has been removed. Therefore retaining the ptl of a migration
entry is sufficient to ensure the page has a reference. Reworking
migration_entry_wait() to hold the ptl until the wait setup is complete
means the extra page reference is no longer needed.
[apopple@nvidia.com: v5]
Link: https://lkml.kernel.org/r/20211213033848.1973946-1-apopple@nvidia.com
Link: https://lkml.kernel.org/r/20211118020754.954425-1-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc updates from Andrew Morton:
"146 patches.
Subsystems affected by this patch series: kthread, ia64, scripts,
ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (146 commits)
mm/damon: hide kernel pointer from tracepoint event
mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
mm/damon/dbgfs: remove an unnecessary variable
mm/damon: move the implementation of damon_insert_region to damon.h
mm/damon: add access checking for hugetlb pages
Docs/admin-guide/mm/damon/usage: update for schemes statistics
mm/damon/dbgfs: support all DAMOS stats
Docs/admin-guide/mm/damon/reclaim: document statistics parameters
mm/damon/reclaim: provide reclamation statistics
mm/damon/schemes: account how many times quota limit has exceeded
mm/damon/schemes: account scheme actions that successfully applied
mm/damon: remove a mistakenly added comment for a future feature
Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
Docs/admin-guide/mm/damon/usage: remove redundant information
Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
mm/damon: convert macro functions to static inline functions
mm/damon: modify damon_rand() macro to static inline function
mm/damon: move damon_rand() definition into damon.h
...
The variable addr is being set and incremented in a for-loop but not
actually being used. It is redundant and so addr and also variable
start can be removed.
Link: https://lkml.kernel.org/r/20211221185729.609630-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now, node_demotion and next_demotion_node() are placed between
__unmap_and_move() and unmap_and_move(). This hurts code readability.
So move them near their users in the file. There's no functionality
change in this patch.
Link: https://lkml.kernel.org/r/20211206031227.3323097-1-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Wei Xu <weixugc@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have some machines with multiple memory types like below, which have
one fast (DRAM) memory node and two slow (persistent memory) memory
nodes. According to current node demotion policy, if node 0 fills up,
its memory should be migrated to node 1, when node 1 fills up, its
memory will be migrated to node 2: node 0 -> node 1 -> node 2 ->stop.
But this is not efficient and suitbale memory migration route for our
machine with multiple slow memory nodes. Since the distance between
node 0 to node 1 and node 0 to node 2 is equal, and memory migration
between slow memory nodes will increase persistent memory bandwidth
greatly, which will hurt the whole system's performance.
Thus for this case, we can treat the slow memory node 1 and node 2 as a
whole slow memory region, and we should migrate memory from node 0 to
node 1 and node 2 if node 0 fills up.
This patch changes the node_demotion data structure to support multiple
target nodes, and establishes the migration path to support multiple
target nodes with validating if the node distance is the best or not.
available: 3 nodes (0-2)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
node 0 size: 62153 MB
node 0 free: 55135 MB
node 1 cpus:
node 1 size: 127007 MB
node 1 free: 126930 MB
node 2 cpus:
node 2 size: 126968 MB
node 2 free: 126878 MB
node distances:
node 0 1 2
0: 10 20 20
1: 20 10 20
2: 20 20 10
Link: https://lkml.kernel.org/r/00728da107789bb4ed9e0d28b1d08fd8056af2ef.1636697263.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: zhongjiang-ali <zhongjiang-ali@linux.alibaba.com>
Cc: Xunlei Pang <xlpang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Correct the migration stats for hugetlb with using compound_nr() instead
of thp_nr_pages(), meanwhile change 'nr_failed_pages' to record the
number of normal pages failed to migrate, including THP and hugetlb, and
'nr_succeeded' will record the number of normal pages migrated
successfully.
[baolin.wang@linux.alibaba.com: fix docs, per Mike]
Link: https://lkml.kernel.org/r/141bdfc6-f898-3cc3-f692-726c5f6cb74d@linux.alibaba.com
Link: https://lkml.kernel.org/r/71a4b6c22f208728fe8c78ad26375436c4ff9704.1636275127.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Improve the migration stats".
According to talk with Zi Yan [1], this patch set changes the return
value of migrate_pages() to avoid returning a number which is larger
than the number of pages the users tried to migrate by move_pages()
syscall. Also fix the hugetlb migration stats and migration stats in
trace_mm_compaction_migratepages().
[1] https://lore.kernel.org/linux-mm/7E44019D-2A5D-4BA7-B4D5-00D4712F1687@nvidia.com/
This patch (of 3):
As Zi Yan pointed out, the syscall move_pages() can return a
non-migrated number larger than the number of pages the users tried to
migrate, when a THP page is failed to migrate. This is confusing for
users.
Since other migration scenarios do not care about the actual
non-migrated number of pages except the memory compaction migration
which will fix in following patch. Thus we can change the return value
to return the number of {normal page, THP, hugetlb} instead to avoid
this issue, and the number of THP splits will be considered as the
number of non-migrated THP, no matter how many subpages of the THP are
migrated successfully. Meanwhile we should still keep the migration
counters using the number of normal pages.
Link: https://lkml.kernel.org/r/cover.1636275127.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/6486fabc3e8c66ff613e150af25e89b3147977a6.1636275127.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Zi Yan <ziy@nvidia.com>
Co-developed-by: Zi Yan <ziy@nvidia.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "page table check", v3.
Ensure that some memory corruptions are prevented by checking at the
time of insertion of entries into user page tables that there is no
illegal sharing.
We have recently found a problem [1] that existed in kernel since 4.14.
The problem was caused by broken page ref count and led to memory
leaking from one process into another. The problem was accidentally
detected by studying a dump of one process and noticing that one page
contains memory that should not belong to this process.
There are some other page->_refcount related problems that were recently
fixed: [2], [3] which potentially could also lead to illegal sharing.
In addition to hardening refcount [4] itself, this work is an attempt to
prevent this class of memory corruption issues.
It uses a simple state machine that is independent from regular MM logic
to check for illegal sharing at time pages are inserted and removed from
page tables.
[1] https://lore.kernel.org/all/xr9335nxwc5y.fsf@gthelen2.svl.corp.google.com
[2] https://lore.kernel.org/all/1582661774-30925-2-git-send-email-akaher@vmware.com
[3] https://lore.kernel.org/all/20210622021423.154662-3-mike.kravetz@oracle.com
[4] https://lore.kernel.org/all/20211221150140.988298-1-pasha.tatashin@soleen.com
This patch (of 4):
There are a few places where we first update the entry in the user page
table, and later change the struct page to indicate that this is
anonymous or file page.
In most places, however, we first configure the page metadata and then
insert entries into the page table. Page table check, will use the
information from struct page to verify the type of entry is inserted.
Change the order in all places to first update struct page, and later to
update page table.
This means that we first do calls that may change the type of page (anon
or file):
page_move_anon_rmap
page_add_anon_rmap
do_page_add_anon_rmap
page_add_new_anon_rmap
page_add_file_rmap
hugepage_add_anon_rmap
hugepage_add_new_anon_rmap
And after that do calls that add entries to the page table:
set_huge_pte_at
set_pte_at
Link: https://lkml.kernel.org/r/20211221154650.1047963-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20211221154650.1047963-2-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Paul Turner <pjt@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Will Deacon <will@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We currently store large folios as 2^N consecutive entries. While this
consumes rather more memory than necessary, it also turns out to be buggy.
A writeback operation which starts within a tail page of a dirty folio will
not write back the folio as the xarray's dirty bit is only set on the
head index. With multi-index entries, the dirty bit will be found no
matter where in the folio the operation starts.
This does end up simplifying the page cache slightly, although not as
much as I had hoped.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Convert all three callers of put_and_wait_on_page_locked() to
folio_put_wait_locked(). This shrinks the kernel overall by 19 bytes.
filemap_update_page() shrinks by 19 bytes while __migration_entry_wait()
is unchanged. folio_put_wait_locked() is 14 bytes smaller than
put_and_wait_on_page_locked(), but pmd_migration_entry_wait() grows by
14 bytes. It removes the assumption from pmd_migration_entry_wait()
that pages cannot be larger than a PMD (which is true today, but
may be interesting to explore in the future).
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
MIGRATE_PFN_LOCKED is used to indicate to migrate_vma_prepare() that a
source page was already locked during migrate_vma_collect(). If it
wasn't then the a second attempt is made to lock the page. However if
the first attempt failed it's unlikely a second attempt will succeed,
and the retry adds complexity. So clean this up by removing the retry
and MIGRATE_PFN_LOCKED flag.
Destination pages are also meant to have the MIGRATE_PFN_LOCKED flag
set, but nothing actually checks that.
Link: https://lkml.kernel.org/r/20211025041608.289017-1-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no need to validate the file-backed page's refcount before
trying to freeze the page's expected refcount, instead we can rely on
the folio_ref_freeze() to validate if the page has the expected refcount
before migrating its mapping.
Moreover we are always under the page lock when migrating the page
mapping, which means nowhere else can remove it from the page cache, so
we can remove the xas_load() validation under the i_pages lock.
Link: https://lkml.kernel.org/r/cover.1629447552.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/df4c129fd8e86a95dbc55f4663d77441cc0d3bd1.1629447552.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc updates from Andrew Morton:
"257 patches.
Subsystems affected by this patch series: scripts, ocfs2, vfs, and
mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache,
gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc,
pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools,
memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm,
vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram,
cleanups, kfence, and damon)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits)
mm/damon: remove return value from before_terminate callback
mm/damon: fix a few spelling mistakes in comments and a pr_debug message
mm/damon: simplify stop mechanism
Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions
Docs/admin-guide/mm/damon/start: simplify the content
Docs/admin-guide/mm/damon/start: fix a wrong link
Docs/admin-guide/mm/damon/start: fix wrong example commands
mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on
mm/damon: remove unnecessary variable initialization
Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM
mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM)
selftests/damon: support watermarks
mm/damon/dbgfs: support watermarks
mm/damon/schemes: activate schemes based on a watermarks mechanism
tools/selftests/damon: update for regions prioritization of schemes
mm/damon/dbgfs: support prioritization weights
mm/damon/vaddr,paddr: support pageout prioritization
mm/damon/schemes: prioritize regions within the quotas
mm/damon/selftests: support schemes quotas
mm/damon/dbgfs: support quotas of schemes
...
The memory demotion needs to call migrate_pages() to do the jobs. And
it is controlled by a knob, however, the knob doesn't depend on
CONFIG_MIGRATION. The knob could be truned on even though MIGRATION is
disabled, this will not cause any crash since migrate_pages() would just
return -ENOSYS. But it is definitely not optimal to go through demotion
path then retry regular swap every time.
And it doesn't make too much sense to have the knob visible to the users
when !MIGRATION. Move the related code from mempolicy.[h|c] to
migrate.[h|c].
Link: https://lkml.kernel.org/r/20211015005559.246709-1-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add memory folios, a new type to represent either order-0 pages or
the head page of a compound page. This should be enough infrastructure
to support filesystems converting from pages to folios.
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Merge tag 'folio-5.16' of git://git.infradead.org/users/willy/pagecache
Pull memory folios from Matthew Wilcox:
"Add memory folios, a new type to represent either order-0 pages or the
head page of a compound page. This should be enough infrastructure to
support filesystems converting from pages to folios.
The point of all this churn is to allow filesystems and the page cache
to manage memory in larger chunks than PAGE_SIZE. The original plan
was to use compound pages like THP does, but I ran into problems with
some functions expecting only a head page while others expect the
precise page containing a particular byte.
The folio type allows a function to declare that it's expecting only a
head page. Almost incidentally, this allows us to remove various calls
to VM_BUG_ON(PageTail(page)) and compound_head().
This converts just parts of the core MM and the page cache. For 5.17,
we intend to convert various filesystems (XFS and AFS are ready; other
filesystems may make it) and also convert more of the MM and page
cache to folios. For 5.18, multi-page folios should be ready.
The multi-page folios offer some improvement to some workloads. The
80% win is real, but appears to be an artificial benchmark (postgres
startup, which isn't a serious workload). Real workloads (eg building
the kernel, running postgres in a steady state, etc) seem to benefit
between 0-10%. I haven't heard of any performance losses as a result
of this series. Nobody has done any serious performance tuning; I
imagine that tweaking the readahead algorithm could provide some more
interesting wins. There are also other places where we could choose to
create large folios and currently do not, such as writes that are
larger than PAGE_SIZE.
I'd like to thank all my reviewers who've offered review/ack tags:
Christoph Hellwig, David Howells, Jan Kara, Jeff Layton, Johannes
Weiner, Kirill A. Shutemov, Michal Hocko, Mike Rapoport, Vlastimil
Babka, William Kucharski, Yu Zhao and Zi Yan.
I'd also like to thank those who gave feedback I incorporated but
haven't offered up review tags for this part of the series: Nick
Piggin, Mel Gorman, Ming Lei, Darrick Wong, Ted Ts'o, John Hubbard,
Hugh Dickins, and probably a few others who I forget"
* tag 'folio-5.16' of git://git.infradead.org/users/willy/pagecache: (90 commits)
mm/writeback: Add folio_write_one
mm/filemap: Add FGP_STABLE
mm/filemap: Add filemap_get_folio
mm/filemap: Convert mapping_get_entry to return a folio
mm/filemap: Add filemap_add_folio()
mm/filemap: Add filemap_alloc_folio
mm/page_alloc: Add folio allocation functions
mm/lru: Add folio_add_lru()
mm/lru: Convert __pagevec_lru_add_fn to take a folio
mm: Add folio_evictable()
mm/workingset: Convert workingset_refault() to take a folio
mm/filemap: Add readahead_folio()
mm/filemap: Add folio_mkwrite_check_truncate()
mm/filemap: Add i_blocks_per_folio()
mm/writeback: Add folio_redirty_for_writepage()
mm/writeback: Add folio_account_redirty()
mm/writeback: Add folio_clear_dirty_for_io()
mm/writeback: Add folio_cancel_dirty()
mm/writeback: Add folio_account_cleaned()
mm/writeback: Add filemap_dirty_folio()
...
The node demotion order needs to be updated during CPU hotplug. Because
whether a NUMA node has CPU may influence the demotion order. The
update function should be called during CPU online/offline after the
node_states[N_CPU] has been updated. That is done in
CPUHP_AP_ONLINE_DYN during CPU online and in CPUHP_MM_VMSTAT_DEAD during
CPU offline. But in commit 884a6e5d1f ("mm/migrate: update node
demotion order on hotplug events"), the function to update node demotion
order is called in CPUHP_AP_ONLINE_DYN during CPU online/offline. This
doesn't satisfy the order requirement.
For example, there are 4 CPUs (P0, P1, P2, P3) in 2 sockets (P0, P1 in S0
and P2, P3 in S1), the demotion order is
- S0 -> NUMA_NO_NODE
- S1 -> NUMA_NO_NODE
After P2 and P3 is offlined, because S1 has no CPU now, the demotion
order should have been changed to
- S0 -> S1
- S1 -> NO_NODE
but it isn't changed, because the order updating callback for CPU
hotplug doesn't see the new nodemask. After that, if P1 is offlined,
the demotion order is changed to the expected order as above.
So in this patch, we added CPUHP_AP_MM_DEMOTION_ONLINE and
CPUHP_MM_DEMOTION_DEAD to be called after CPUHP_AP_ONLINE_DYN and
CPUHP_MM_VMSTAT_DEAD during CPU online and offline, and register the
update function on them.
Link: https://lkml.kernel.org/r/20210929060351.7293-1-ying.huang@intel.com
Fixes: 884a6e5d1f ("mm/migrate: update node demotion order on hotplug events")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Keith Busch <kbusch@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Once upon a time, the node demotion updates were driven solely by memory
hotplug events. But now, there are handlers for both CPU and memory
hotplug.
However, the #ifdef around the code checks only memory hotplug. A
system that has HOTPLUG_CPU=y but MEMORY_HOTPLUG=n would miss CPU
hotplug events.
Update the #ifdef around the common code. Add memory and CPU-specific
#ifdefs for their handlers. These memory/CPU #ifdefs avoid unused
function warnings when their Kconfig option is off.
[arnd@arndb.de: rework hotplug_memory_notifier() stub]
Link: https://lkml.kernel.org/r/20211013144029.2154629-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20210924161255.E5FE8F7E@davehans-spike.ostc.intel.com
Fixes: 884a6e5d1f ("mm/migrate: update node demotion order on hotplug events")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/migrate: 5.15 fixes for automatic demotion", v2.
This contains two fixes for the "automatic demotion" code which was
merged into 5.15:
* Fix memory hotplug performance regression by watching
suppressing any real action on irrelevant hotplug events.
* Ensure CPU hotplug handler is registered when memory hotplug
is disabled.
This patch (of 2):
== tl;dr ==
Automatic demotion opted for a simple, lazy approach to handling hotplug
events. This noticeably slows down memory hotplug[1]. Optimize away
updates to the demotion order when memory hotplug events should have no
effect.
This has no effect on CPU hotplug. There is no known problem on the CPU
side and any work there will be in a separate series.
== Background ==
Automatic demotion is a memory migration strategy to ensure that new
allocations have room in faster memory tiers on tiered memory systems.
The kernel maintains an array (node_demotion[]) to drive these
migrations.
The node_demotion[] path is calculated by starting at nodes with CPUs
and then "walking" to nodes with memory. Only hotplug events which
online or offline a node with memory (N_ONLINE) or CPUs (N_CPU) will
actually affect the migration order.
== Problem ==
However, the current code is lazy. It completely regenerates the
migration order on *any* CPU or memory hotplug event. The logic was
that these events are extremely rare and that the overhead from
indiscriminate order regeneration is minimal.
Part of the update logic involves a synchronize_rcu(), which is a pretty
big hammer. Its overhead was large enough to be detected by some 0day
tests that watch memory hotplug performance[1].
== Solution ==
Add a new helper (node_demotion_topo_changed()) which can differentiate
between superfluous and impactful hotplug events. Skip the expensive
update operation for superfluous events.
== Aside: Locking ==
It took me a few moments to declare the locking to be safe enough for
node_demotion_topo_changed() to work. It all hinges on the memory
hotplug lock:
During memory hotplug events, 'mem_hotplug_lock' is held for write.
This ensures that two memory hotplug events can not be called
simultaneously.
CPU hotplug has a similar lock (cpuhp_state_mutex) which also provides
mutual exclusion between CPU hotplug events. In addition, the demotion
code acquire and hold the mem_hotplug_lock for read during its CPU
hotplug handlers. This provides mutual exclusion between the demotion
memory hotplug callbacks and the CPU hotplug callbacks.
This effectively allows treating the migration target generation code to
act as if it is single-threaded.
1. https://lore.kernel.org/all/20210905135932.GE15026@xsang-OptiPlex-9020/
Link: https://lkml.kernel.org/r/20210924161251.093CCD06@davehans-spike.ostc.intel.com
Link: https://lkml.kernel.org/r/20210924161253.D7673E31@davehans-spike.ostc.intel.com
Fixes: 884a6e5d1f ("mm/migrate: update node demotion order on hotplug events")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the folio equivalent of migrate_page_copy(), which is retained
as a wrapper for filesystems which are not yet converted to folios.
Also convert copy_huge_page() to folio_copy().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Turn migrate_page_states() into a wrapper around folio_migrate_flags().
Also convert two functions only called from folio_migrate_flags() to
be folio-based. ksm_migrate_page() becomes folio_migrate_ksm() and
copy_page_owner() becomes folio_copy_owner(). folio_migrate_flags()
alone shrinks by two thirds -- 1967 bytes down to 642 bytes.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reimplement migrate_page_move_mapping() as a wrapper around
folio_migrate_mapping(). Saves 193 bytes of kernel text.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Convert all callers of mem_cgroup_migrate() to call page_folio() first.
They all look like they're using head pages already, but this proves it.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Convert all callers of mem_cgroup_charge() to call page_folio() on the
page they're currently passing in. Many of them will be converted to
use folios themselves soon.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
These are all handled correctly when calling the native system call entry
point, so remove the special cases.
Link: https://lkml.kernel.org/r/20210727144859.4150043-6-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The compat move_pages() implementation uses compat_alloc_user_space() for
converting the pointer array. Moving the compat handling into the
function itself is a bit simpler and lets us avoid the
compat_alloc_user_space() call.
Link: https://lkml.kernel.org/r/20210727144859.4150043-4-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change to use bool type for 'page_was_mapped' variable making it more
readable.
Link: https://lkml.kernel.org/r/ce1279df18d2c163998c403e0b5ec6d3f6f90f7a.1629447552.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
since commit a98a2f0c8c ("mm/rmap: split migration into its own
function"), the migration ptes establishment has been split into a
separate try_to_migrate() function, thus update the related comments.
Link: https://lkml.kernel.org/r/5b824bad6183259c916ae6cf42f81d14c6118b06.1629447552.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use thp_nr_pages() instead of compound_nr() to get the number of pages for
THP page, meanwhile introducing a local variable 'nr_pages' to avoid
getting the number of pages repeatedly.
Link: https://lkml.kernel.org/r/a8e331ac04392ee230c79186330fb05e86a2aa77.1629447552.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the expected "Return:" format to prevent a kernel-doc warning.
mm/migrate.c:1157: warning: Excess function parameter 'returns' description in 'next_demotion_node'
Link: https://lkml.kernel.org/r/20210808203151.10632-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Under normal circumstances, migrate_pages() returns the number of pages
migrated. In error conditions, it returns an error code. When returning
an error code, there is no way to know how many pages were migrated or not
migrated.
Make migrate_pages() return how many pages are demoted successfully for
all cases, including when encountering errors. Page reclaim behavior will
depend on this in subsequent patches.
Link: https://lkml.kernel.org/r/20210721063926.3024591-3-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20210715055145.195411-4-ying.huang@intel.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-by: Oscar Salvador <osalvador@suse.de> [optional parameter]
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Keith Busch <kbusch@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reclaim-based migration is attempting to optimize data placement in memory
based on the system topology. If the system changes, so must the
migration ordering.
The implementation is conceptually simple and entirely unoptimized. On
any memory or CPU hotplug events, assume that a node was added or removed
and recalculate all migration targets. This ensures that the
node_demotion[] array is always ready to be used in case the new reclaim
mode is enabled.
This recalculation is far from optimal, most glaringly that it does not
even attempt to figure out the hotplug event would have some *actual*
effect on the demotion order. But, given the expected paucity of hotplug
events, this should be fine.
Link: https://lkml.kernel.org/r/20210721063926.3024591-2-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20210715055145.195411-3-ying.huang@intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Migrate Pages in lieu of discard", v11.
We're starting to see systems with more and more kinds of memory such as
Intel's implementation of persistent memory.
Let's say you have a system with some DRAM and some persistent memory.
Today, once DRAM fills up, reclaim will start and some of the DRAM
contents will be thrown out. Allocations will, at some point, start
falling over to the slower persistent memory.
That has two nasty properties. First, the newer allocations can end up in
the slower persistent memory. Second, reclaimed data in DRAM are just
discarded even if there are gobs of space in persistent memory that could
be used.
This patchset implements a solution to these problems. At the end of the
reclaim process in shrink_page_list() just before the last page refcount
is dropped, the page is migrated to persistent memory instead of being
dropped.
While I've talked about a DRAM/PMEM pairing, this approach would function
in any environment where memory tiers exist.
This is not perfect. It "strands" pages in slower memory and never brings
them back to fast DRAM. Huang Ying has follow-on work which repurposes
NUMA balancing to promote hot pages back to DRAM.
This is also all based on an upstream mechanism that allows persistent
memory to be onlined and used as if it were volatile:
http://lkml.kernel.org/r/20190124231441.37A4A305@viggo.jf.intel.com
With that, the DRAM and PMEM in each socket will be represented as 2
separate NUMA nodes, with the CPUs sit in the DRAM node. So the
general inter-NUMA demotion mechanism introduced in the patchset can
migrate the cold DRAM pages to the PMEM node.
We have tested the patchset with the postgresql and pgbench. On a
2-socket server machine with DRAM and PMEM, the kernel with the patchset
can improve the score of pgbench up to 22.1% compared with that of the
DRAM only + disk case. This comes from the reduced disk read throughput
(which reduces up to 70.8%).
== Open Issues ==
* Memory policies and cpusets that, for instance, restrict allocations
to DRAM can be demoted to PMEM whenever they opt in to this
new mechanism. A cgroup-level API to opt-in or opt-out of
these migrations will likely be required as a follow-on.
* Could be more aggressive about where anon LRU scanning occurs
since it no longer necessarily involves I/O. get_scan_count()
for instance says: "If we have no swap space, do not bother
scanning anon pages"
This patch (of 9):
Prepare for the kernel to auto-migrate pages to other memory nodes with a
node migration table. This allows creating single migration target for
each NUMA node to enable the kernel to do NUMA page migrations instead of
simply discarding colder pages. A node with no target is a "terminal
node", so reclaim acts normally there. The migration target does not
fundamentally _need_ to be a single node, but this implementation starts
there to limit complexity.
When memory fills up on a node, memory contents can be automatically
migrated to another node. The biggest problems are knowing when to
migrate and to where the migration should be targeted.
The most straightforward way to generate the "to where" list would be to
follow the page allocator fallback lists. Those lists already tell us if
memory is full where to look next. It would also be logical to move
memory in that order.
But, the allocator fallback lists have a fatal flaw: most nodes appear in
all the lists. This would potentially lead to migration cycles (A->B,
B->A, A->B, ...).
Instead of using the allocator fallback lists directly, keep a separate
node migration ordering. But, reuse the same data used to generate page
allocator fallback in the first place: find_next_best_node().
This means that the firmware data used to populate node distances
essentially dictates the ordering for now. It should also be
architecture-neutral since all NUMA architectures have a working
find_next_best_node().
RCU is used to allow lock-less read of node_demotion[] and prevent
demotion cycles been observed. If multiple reads of node_demotion[] are
performed, a single rcu_read_lock() must be held over all reads to ensure
no cycles are observed. Details are as follows.
=== What does RCU provide? ===
Imagine a simple loop which walks down the demotion path looking
for the last node:
terminal_node = start_node;
while (node_demotion[terminal_node] != NUMA_NO_NODE) {
terminal_node = node_demotion[terminal_node];
}
The initial values are:
node_demotion[0] = 1;
node_demotion[1] = NUMA_NO_NODE;
and are updated to:
node_demotion[0] = NUMA_NO_NODE;
node_demotion[1] = 0;
What guarantees that the cycle is not observed:
node_demotion[0] = 1;
node_demotion[1] = 0;
and would loop forever?
With RCU, a rcu_read_lock/unlock() can be placed around the loop. Since
the write side does a synchronize_rcu(), the loop that observed the old
contents is known to be complete before the synchronize_rcu() has
completed.
RCU, combined with disable_all_migrate_targets(), ensures that the old
migration state is not visible by the time __set_migration_target_nodes()
is called.
=== What does READ_ONCE() provide? ===
READ_ONCE() forbids the compiler from merging or reordering successive
reads of node_demotion[]. This ensures that any updates are *eventually*
observed.
Consider the above loop again. The compiler could theoretically read the
entirety of node_demotion[] into local storage (registers) and never go
back to memory, and *permanently* observe bad values for node_demotion[].
Note: RCU does not provide any universal compiler-ordering
guarantees:
https://lore.kernel.org/lkml/20150921204327.GH4029@linux.vnet.ibm.com/
This code is unused for now. It will be called later in the
series.
Link: https://lkml.kernel.org/r/20210721063926.3024591-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20210715055145.195411-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20210715055145.195411-2-ying.huang@intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Xu <weixugc@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Similar to commit 2da9f6305f ("mm/vmscan: fix NR_ISOLATED_FILE
corruption on 64-bit") avoid using unsigned int for nr_pages. With
unsigned int type the large unsigned int converts to a large positive
signed long.
Symptoms include CMA allocations hanging forever due to
alloc_contig_range->...->isolate_migratepages_block waiting forever in
"while (unlikely(too_many_isolated(pgdat)))".
Link: https://lkml.kernel.org/r/20210728042531.359409-1-aneesh.kumar@linux.ibm.com
Fixes: c5fc5c3ae0 ("mm: migrate: account THP NUMA migration counters correctly")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Nicholas Piggin <npiggin@gmail.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>
Rewrite copy_huge_page() and move it into mm/util.c so it's always
available. Fixes an exposure of uninitialised memory on configurations
with HUGETLB and UFFD enabled and MIGRATION disabled.
Fixes: 8cc5fcbb5b ("mm, hugetlb: fix racy resv_huge_pages underflow on UFFDIO_COPY")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MMU notifier ranges have a migrate_pgmap_owner field which is used by
drivers to store a pointer. This is subsequently used by the driver
callback to filter MMU_NOTIFY_MIGRATE events. Other notifier event types
can also benefit from this filtering, so rename the 'migrate_pgmap_owner'
field to 'owner' and create a new notifier initialisation function to
initialise this field.
Link: https://lkml.kernel.org/r/20210616105937.23201-6-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Suggested-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Migration is currently implemented as a mode of operation for
try_to_unmap_one() generally specified by passing the TTU_MIGRATION flag
or in the case of splitting a huge anonymous page TTU_SPLIT_FREEZE.
However it does not have much in common with the rest of the unmap
functionality of try_to_unmap_one() and thus splitting it into a separate
function reduces the complexity of try_to_unmap_one() making it more
readable.
Several simplifications can also be made in try_to_migrate_one() based on
the following observations:
- All users of TTU_MIGRATION also set TTU_IGNORE_MLOCK.
- No users of TTU_MIGRATION ever set TTU_IGNORE_HWPOISON.
- No users of TTU_MIGRATION ever set TTU_BATCH_FLUSH.
TTU_SPLIT_FREEZE is a special case of migration used when splitting an
anonymous page. This is most easily dealt with by calling the correct
function from unmap_page() in mm/huge_memory.c - either try_to_migrate()
for PageAnon or try_to_unmap().
Link: https://lkml.kernel.org/r/20210616105937.23201-5-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Both migration and device private pages use special swap entries that are
manipluated by a range of inline functions. The arguments to these are
somewhat inconsistent so rework them to remove flag type arguments and to
make the arguments similar for both read and write entry creation.
Link: https://lkml.kernel.org/r/20210616105937.23201-3-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Add support for SVM atomics in Nouveau", v11.
Introduction
============
Some devices have features such as atomic PTE bits that can be used to
implement atomic access to system memory. To support atomic operations to
a shared virtual memory page such a device needs access to that page which
is exclusive of the CPU. This series introduces a mechanism to
temporarily unmap pages granting exclusive access to a device.
These changes are required to support OpenCL atomic operations in Nouveau
to shared virtual memory (SVM) regions allocated with the
CL_MEM_SVM_ATOMICS clSVMAlloc flag. A more complete description of the
OpenCL SVM feature is available at
https://www.khronos.org/registry/OpenCL/specs/3.0-unified/html/
OpenCL_API.html#_shared_virtual_memory .
Implementation
==============
Exclusive device access is implemented by adding a new swap entry type
(SWAP_DEVICE_EXCLUSIVE) which is similar to a migration entry. The main
difference is that on fault the original entry is immediately restored by
the fault handler instead of waiting.
Restoring the entry triggers calls to MMU notifers which allows a device
driver to revoke the atomic access permission from the GPU prior to the
CPU finalising the entry.
Patches
=======
Patches 1 & 2 refactor existing migration and device private entry
functions.
Patches 3 & 4 rework try_to_unmap_one() by splitting out unrelated
functionality into separate functions - try_to_migrate_one() and
try_to_munlock_one().
Patch 5 renames some existing code but does not introduce functionality.
Patch 6 is a small clean-up to swap entry handling in copy_pte_range().
Patch 7 contains the bulk of the implementation for device exclusive
memory.
Patch 8 contains some additions to the HMM selftests to ensure everything
works as expected.
Patch 9 is a cleanup for the Nouveau SVM implementation.
Patch 10 contains the implementation of atomic access for the Nouveau
driver.
Testing
=======
This has been tested with upstream Mesa 21.1.0 and a simple OpenCL program
which checks that GPU atomic accesses to system memory are atomic.
Without this series the test fails as there is no way of write-protecting
the page mapping which results in the device clobbering CPU writes. For
reference the test is available at
https://ozlabs.org/~apopple/opencl_svm_atomics/
Further testing has been performed by adding support for testing exclusive
access to the hmm-tests kselftests.
This patch (of 10):
Remove multiple similar inline functions for dealing with different types
of special swap entries.
Both migration and device private swap entries use the swap offset to
store a pfn. Instead of multiple inline functions to obtain a struct page
for each swap entry type use a common function pfn_swap_entry_to_page().
Also open-code the various entry_to_pfn() functions as this results is
shorter code that is easier to understand.
Link: https://lkml.kernel.org/r/20210616105937.23201-1-apopple@nvidia.com
Link: https://lkml.kernel.org/r/20210616105937.23201-2-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The generic migration path will check refcount, so no need check refcount
here. But the old code actually prevents from migrating shared THP
(mapped by multiple processes), so bail out early if mapcount is > 1 to
keep the behavior.
Link: https://lkml.kernel.org/r/20210518200801.7413-7-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The old behavior didn't split THP if migration is failed due to lack of
memory on the target node. But the THP migration does split THP, so keep
the old behavior for misplaced NUMA page migration.
Link: https://lkml.kernel.org/r/20210518200801.7413-6-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now both base page and THP NUMA migration is done via
migrate_misplaced_page(), keep the counters correctly for THP.
Link: https://lkml.kernel.org/r/20210518200801.7413-5-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the THP NUMA fault support was added THP migration was not supported
yet. So the ad hoc THP migration was implemented in NUMA fault handling.
Since v4.14 THP migration has been supported so it doesn't make too much
sense to still keep another THP migration implementation rather than using
the generic migration code.
This patch reworks the NUMA fault handling to use generic migration
implementation to migrate misplaced page. There is no functional change.
After the refactor the flow of NUMA fault handling looks just like its
PTE counterpart:
Acquire ptl
Prepare for migration (elevate page refcount)
Release ptl
Isolate page from lru and elevate page refcount
Migrate the misplaced THP
If migration fails just restore the old normal PMD.
In the old code anon_vma lock was needed to serialize THP migration
against THP split, but since then the THP code has been reworked a lot, it
seems anon_vma lock is not required anymore to avoid the race.
The page refcount elevation when holding ptl should prevent from THP
split.
Use migrate_misplaced_page() for both base page and THP NUMA hinting fault
and remove all the dead and duplicate code.
[dan.carpenter@oracle.com: fix a double unlock bug]
Link: https://lkml.kernel.org/r/YLX8uYN01JmfLnlK@mwanda
Link: https://lkml.kernel.org/r/20210518200801.7413-4-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit d6995da311 ("hugetlb: use page.private for hugetlb specific
page flags") converts page.private for hugetlb specific page flags. We
should use hugetlb_page_subpool() to get the subpool pointer instead of
page_private().
This 'could' prevent the migration of hugetlb pages. page_private(hpage)
is now used for hugetlb page specific flags. At migration time, the only
flag which could be set is HPageVmemmapOptimized. This flag will only be
set if the new vmemmap reduction feature is enabled. In addition,
!page_mapping() implies an anonymous mapping. So, this will prevent
migration of hugetb pages in anonymous mappings if the vmemmap reduction
feature is enabled.
In addition, that if statement checked for the rare race condition of a
page being migrated while in the process of being freed. Since that check
is now wrong, we could leak hugetlb subpool usage counts.
The commit forgot to update it in the page migration routine. So fix it.
[songmuchun@bytedance.com: fix compiler error when !CONFIG_HUGETLB_PAGE reported by Randy]
Link: https://lkml.kernel.org/r/20210521022747.35736-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20210520025949.1866-1-songmuchun@bytedance.com
Fixes: d6995da311 ("hugetlb: use page.private for hugetlb specific page flags")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reported-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Anshuman Khandual <anshuman.khandual@arm.com> [arm64]
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On UFFDIO_COPY, if we fail to copy the page contents while holding the
hugetlb_fault_mutex, we will drop the mutex and return to the caller after
allocating a page that consumed a reservation. In this case there may be
a fault that double consumes the reservation. To handle this, we free the
allocated page, fix the reservations, and allocate a temporary hugetlb
page and return that to the caller. When the caller does the copy outside
of the lock, we again check the cache, and allocate a page consuming the
reservation, and copy over the contents.
Test:
Hacked the code locally such that resv_huge_pages underflows produce
a warning and the copy_huge_page_from_user() always fails, then:
./tools/testing/selftests/vm/userfaultfd hugetlb_shared 10
2 /tmp/kokonut_test/huge/userfaultfd_test && echo test success
./tools/testing/selftests/vm/userfaultfd hugetlb 10
2 /tmp/kokonut_test/huge/userfaultfd_test && echo test success
Both tests succeed and produce no warnings. After the
test runs number of free/resv hugepages is correct.
[yuehaibing@huawei.com: remove set but not used variable 'vm_alloc_shared']
Link: https://lkml.kernel.org/r/20210601141610.28332-1-yuehaibing@huawei.com
[almasrymina@google.com: fix allocation error check and copy func name]
Link: https://lkml.kernel.org/r/20210605010626.1459873-1-almasrymina@google.com
Link: https://lkml.kernel.org/r/20210528005029.88088-1-almasrymina@google.com
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Peter Xu <peterx@redhat.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>
Patch series "Subject: [PATCH v2 0/5] Implement huge VMAP and VMALLOC on powerpc 8xx", v2.
This series implements huge VMAP and VMALLOC on powerpc 8xx.
Powerpc 8xx has 4 page sizes:
- 4k
- 16k
- 512k
- 8M
At the time being, vmalloc and vmap only support huge pages which are
leaf at PMD level.
Here the PMD level is 4M, it doesn't correspond to any supported
page size.
For now, implement use of 16k and 512k pages which is done
at PTE level.
Support of 8M pages will be implemented later, it requires use of
hugepd tables.
To allow this, the architecture provides two functions:
- arch_vmap_pte_range_map_size() which tells vmap_pte_range() what
page size to use. A stub returning PAGE_SIZE is provided when the
architecture doesn't provide this function.
- arch_vmap_pte_supported_shift() which tells __vmalloc_node_range()
what page shift to use for a given area size. A stub returning
PAGE_SHIFT is provided when the architecture doesn't provide this
function.
This patch (of 5):
At the time being, arch_make_huge_pte() has the following prototype:
pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
struct page *page, int writable);
vma is used to get the pages shift or size.
vma is also used on Sparc to get vm_flags.
page is not used.
writable is not used.
In order to use this function without a vma, replace vma by shift and
flags. Also remove the used parameters.
Link: https://lkml.kernel.org/r/cover.1620795204.git.christophe.leroy@csgroup.eu
Link: https://lkml.kernel.org/r/f4633ac6a7da2f22f31a04a89e0a7026bb78b15b.1620795204.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When we free a HugeTLB page to the buddy allocator, we need to allocate
the vmemmap pages associated with it. However, we may not be able to
allocate the vmemmap pages when the system is under memory pressure. In
this case, we just refuse to free the HugeTLB page. This changes behavior
in some corner cases as listed below:
1) Failing to free a huge page triggered by the user (decrease nr_pages).
User needs to try again later.
2) Failing to free a surplus huge page when freed by the application.
Try again later when freeing a huge page next time.
3) Failing to dissolve a free huge page on ZONE_MOVABLE via
offline_pages().
This can happen when we have plenty of ZONE_MOVABLE memory, but
not enough kernel memory to allocate vmemmmap pages. We may even
be able to migrate huge page contents, but will not be able to
dissolve the source huge page. This will prevent an offline
operation and is unfortunate as memory offlining is expected to
succeed on movable zones. Users that depend on memory hotplug
to succeed for movable zones should carefully consider whether the
memory savings gained from this feature are worth the risk of
possibly not being able to offline memory in certain situations.
4) Failing to dissolve a huge page on CMA/ZONE_MOVABLE via
alloc_contig_range() - once we have that handling in place. Mainly
affects CMA and virtio-mem.
Similar to 3). virito-mem will handle migration errors gracefully.
CMA might be able to fallback on other free areas within the CMA
region.
Vmemmap pages are allocated from the page freeing context. In order for
those allocations to be not disruptive (e.g. trigger oom killer)
__GFP_NORETRY is used. hugetlb_lock is dropped for the allocation because
a non sleeping allocation would be too fragile and it could fail too
easily under memory pressure. GFP_ATOMIC or other modes to access memory
reserves is not used because we want to prevent consuming reserves under
heavy hugetlb freeing.
[mike.kravetz@oracle.com: fix dissolve_free_huge_page use of tail/head page]
Link: https://lkml.kernel.org/r/20210527231225.226987-1-mike.kravetz@oracle.com
[willy@infradead.org: fix alloc_vmemmap_page_list documentation warning]
Link: https://lkml.kernel.org/r/20210615200242.1716568-6-willy@infradead.org
Link: https://lkml.kernel.org/r/20210510030027.56044-7-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chen Huang <chenhuang5@huawei.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: HORIGUCHI NAOYA <naoya.horiguchi@nec.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use vma_lookup() to find the VMA at a specific address. As vma_lookup()
will return NULL if the address is not within any VMA, the start address
no longer needs to be validated.
Link: https://lkml.kernel.org/r/20210521174745.2219620-20-Liam.Howlett@Oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We notice that hung task happens in a corner but practical scenario when
CONFIG_PREEMPT_NONE is enabled, as follows.
Process 0 Process 1 Process 2..Inf
split_huge_page_to_list
unmap_page
split_huge_pmd_address
__migration_entry_wait(head)
__migration_entry_wait(tail)
remap_page (roll back)
remove_migration_ptes
rmap_walk_anon
cond_resched
Where __migration_entry_wait(tail) is occurred in kernel space, e.g.,
copy_to_user in fstat, which will immediately fault again without
rescheduling, and thus occupy the cpu fully.
When there are too many processes performing __migration_entry_wait on
tail page, remap_page will never be done after cond_resched.
This makes __migration_entry_wait operate on the compound head page,
thus waits for remap_page to complete, whether the THP is split
successfully or roll back.
Note that put_and_wait_on_page_locked helps to drop the page reference
acquired with get_page_unless_zero, as soon as the page is on the wait
queue, before actually waiting. So splitting the THP is only prevented
for a brief interval.
Link: https://lkml.kernel.org/r/b9836c1dd522e903891760af9f0c86a2cce987eb.1623144009.git.xuyu@linux.alibaba.com
Fixes: ba98828088 ("thp: add option to setup migration entries during PMD split")
Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Gang Deng <gavin.dg@linux.alibaba.com>
Signed-off-by: Xu Yu <xuyu@linux.alibaba.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Hugh Dickins <hughd@google.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>
Add cma and migrate trace events to enable CMA allocation performance to
be measured via ftrace.
[georgi.djakov@linaro.org: add the CMA instance name to the cma_alloc_start trace event]
Link: https://lkml.kernel.org/r/20210326155414.25006-1-georgi.djakov@linaro.org
Link: https://lkml.kernel.org/r/20210324160740.15901-1-georgi.djakov@linaro.org
Signed-off-by: Liam Mark <lmark@codeaurora.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit c77c5cbafe.
Since commit c77c5cbafe ("mm: migrate: skip shared exec THP for NUMA
balancing"), the NUMA balancing would skip shared exec transhuge page.
But this enhancement is not suitable for transhuge page. Because it's
required that page_mapcount() must be 1 due to no migration pte dance is
done here. On the other hand, the shared exec transhuge page will leave
the migrate_misplaced_page() with pte entry untouched and page locked.
Thus pagefault for NUMA will be triggered again and deadlock occurs when
we start waiting for the page lock held by ourselves.
Yang Shi said:
"Thanks for catching this. By relooking the code I think the other
important reason for removing this is
migrate_misplaced_transhuge_page() actually can't see shared exec
file THP at all since page_lock_anon_vma_read() is called before
and if page is not anonymous page it will just restore the PMD
without migrating anything.
The pages for private mapped file vma may be anonymous pages due to
COW but they can't be THP so it won't trigger THP numa fault at all. I
think this is why no bug was reported. I overlooked this in the first
place."
Link: https://lkml.kernel.org/r/20210325131524.48181-6-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's more recommended to use helper function migrate_vma_collect_skip() to
skip the unexpected case and it also helps remove some duplicated codes.
Move migrate_vma_collect_skip() above migrate_vma_collect_hole() to avoid
compiler warning.
Link: https://lkml.kernel.org/r/20210325131524.48181-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the zone device page does not belong to un-addressable device memory,
the variable entry will be uninitialized and lead to indeterminate pte
entry ultimately. Fix this unexpected case and warn about it.
Link: https://lkml.kernel.org/r/20210325131524.48181-4-linmiaohe@huawei.com
Fixes: df6ad69838 ("mm/device-public-memory: device memory cache coherent with CPU")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's guaranteed that in the 'else' case of the rc == MIGRATEPAGE_SUCCESS
check, rc does not equal to MIGRATEPAGE_SUCCESS. Remove this unnecessary
check.
Link: https://lkml.kernel.org/r/20210325131524.48181-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Cleanup and fixup for mm/migrate.c", v3.
This series contains cleanups to remove unnecessary VM_BUG_ON_PAGE and rc
!= MIGRATEPAGE_SUCCESS check. Also use helper function to remove some
duplicated codes. What's more, this fixes potential deadlock in NUMA
balancing shared exec THP case and so on. More details can be found in
the respective changelogs.
This patch (of 5):
The putback_movable_page() is just called by putback_movable_pages() and
we know the page is locked and both PageMovable() and PageIsolated() is
checked right before calling putback_movable_page(). So we make it static
and remove all the 3 VM_BUG_ON_PAGE().
Link: https://lkml.kernel.org/r/20210325131524.48181-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210325131524.48181-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, migrate_[prep|finish] is merely a wrapper of
lru_cache_[disable|enable]. There is not much to gain from having
additional abstraction.
Use lru_cache_[disable|enable] instead of migrate_[prep|finish], which
would be more descriptive.
note: migrate_prep_local in compaction.c changed into lru_add_drain to
avoid CPU schedule cost with involving many other CPUs to keep old
behavior.
Link: https://lkml.kernel.org/r/20210319175127.886124-2-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Chris Goldsworthy <cgoldswo@codeaurora.org>
Cc: John Dias <joaodias@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oliver Sang <oliver.sang@intel.com>
Cc: Suren Baghdasaryan <surenb@google.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>
LRU pagevec holds refcount of pages until the pagevec are drained. It
could prevent migration since the refcount of the page is greater than
the expection in migration logic. To mitigate the issue, callers of
migrate_pages drains LRU pagevec via migrate_prep or lru_add_drain_all
before migrate_pages call.
However, it's not enough because pages coming into pagevec after the
draining call still could stay at the pagevec so it could keep
preventing page migration. Since some callers of migrate_pages have
retrial logic with LRU draining, the page would migrate at next trail
but it is still fragile in that it doesn't close the fundamental race
between upcoming LRU pages into pagvec and migration so the migration
failure could cause contiguous memory allocation failure in the end.
To close the race, this patch disables lru caches(i.e, pagevec) during
ongoing migration until migrate is done.
Since it's really hard to reproduce, I measured how many times
migrate_pages retried with force mode(it is about a fallback to a sync
migration) with below debug code.
int migrate_pages(struct list_head *from, new_page_t get_new_page,
..
..
if (rc && reason == MR_CONTIG_RANGE && pass > 2) {
printk(KERN_ERR, "pfn 0x%lx reason %d", page_to_pfn(page), rc);
dump_page(page, "fail to migrate");
}
The test was repeating android apps launching with cma allocation in
background every five seconds. Total cma allocation count was about 500
during the testing. With this patch, the dump_page count was reduced
from 400 to 30.
The new interface is also useful for memory hotplug which currently
drains lru pcp caches after each migration failure. This is rather
suboptimal as it has to disrupt others running during the operation.
With the new interface the operation happens only once. This is also in
line with pcp allocator cache which are disabled for the offlining as
well.
Link: https://lkml.kernel.org/r/20210319175127.886124-1-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Chris Goldsworthy <cgoldswo@codeaurora.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: John Dias <joaodias@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oliver Sang <oliver.sang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are only two callers of __alloc_pages() so prune the thicket of
alloc_page variants by combining the two functions together. Current
callers of __alloc_pages() simply add an extra 'NULL' parameter and
current callers of __alloc_pages_nodemask() call __alloc_pages() instead.
Link: https://lkml.kernel.org/r/20210225150642.2582252-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.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>
This patch adds swapcache stat for the cgroup v2. The swapcache
represents the memory that is accounted against both the memory and the
swap limit of the cgroup. The main motivation behind exposing the
swapcache stat is for enabling users to gracefully migrate from cgroup
v1's memsw counter to cgroup v2's memory and swap counters.
Cgroup v1's memsw limit allows users to limit the memory+swap usage of a
workload but without control on the exact proportion of memory and swap.
Cgroup v2 provides separate limits for memory and swap which enables more
control on the exact usage of memory and swap individually for the
workload.
With some little subtleties, the v1's memsw limit can be switched with the
sum of the v2's memory and swap limits. However the alternative for memsw
usage is not yet available in cgroup v2. Exposing per-cgroup swapcache
stat enables that alternative. Adding the memory usage and swap usage and
subtracting the swapcache will approximate the memsw usage. This will
help in the transparent migration of the workloads depending on memsw
usage and limit to v2' memory and swap counters.
The reasons these applications are still interested in this approximate
memsw usage are: (1) these applications are not really interested in two
separate memory and swap usage metrics. A single usage metric is more
simple to use and reason about for them.
(2) The memsw usage metric hides the underlying system's swap setup from
the applications. Applications with multiple instances running in a
datacenter with heterogeneous systems (some have swap and some don't) will
keep seeing a consistent view of their usage.
[akpm@linux-foundation.org: fix CONFIG_SWAP=n build]
Link: https://lkml.kernel.org/r/20210108155813.2914586-3-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is prep work for the next patch, but I think at least one of the
current callers would prefer a killable sleep to an uninterruptible one.
Link: https://lkml.kernel.org/r/20210122160140.223228-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All pages isolated for the migration have an elevated reference count and
therefore seeing a reference count equal to 1 means that the last user of
the page has dropped the reference and the page has became unused and
there doesn't make much sense to migrate it anymore.
This has been done for regular pages and this patch does the same for
hugetlb pages. Although the likelihood of the race is rather small for
hugetlb pages it makes sense the two code paths in sync.
Link: https://lkml.kernel.org/r/20210115124942.46403-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-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>
Currently the kernel is not correctly updating the numa stats for
NR_FILE_PAGES and NR_SHMEM on THP migration. Fix that.
For NR_FILE_DIRTY and NR_ZONE_WRITE_PENDING, although at the moment
there is no need to handle THP migration as kernel still does not have
write support for file THP but to be more future proof, this patch adds
the THP support for those stats as well.
Link: https://lkml.kernel.org/r/20210108155813.2914586-2-shakeelb@google.com
Fixes: e71769ae52 ("mm: enable thp migration for shmem thp")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The kernel updates the per-node NR_FILE_DIRTY stats on page migration
but not the memcg numa stats.
That was not an issue until recently the commit 5f9a4f4a70 ("mm:
memcontrol: add the missing numa_stat interface for cgroup v2") exposed
numa stats for the memcg.
So fix the file_dirty per-memcg numa stat.
Link: https://lkml.kernel.org/r/20210108155813.2914586-1-shakeelb@google.com
Fixes: 5f9a4f4a70 ("mm: memcontrol: add the missing numa_stat interface for cgroup v2")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
"dst" parameter to migrate_vma_insert_page() is not used anymore.
Link: https://lkml.kernel.org/r/CANubcdUwCAMuUyamG2dkWP=cqSR9MAS=tHLDc95kQkqU-rEnAg@mail.gmail.com
Signed-off-by: Stephen Zhang <starzhangzsd@gmail.com>
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>
In the current implementation unmap_and_move() would return -ENOMEM if THP
migration is unsupported, then the THP will be split. If split is failed
just exit without trying to migrate other pages. It doesn't make too much
sense since there may be enough free memory to migrate other pages and
there may be a lot base pages on the list.
Return -ENOSYS to make consistent with hugetlb. And if THP split is
failed just skip and try other pages on the list.
Just skip the whole list and exit when free memory is really low.
Link: https://lkml.kernel.org/r/20201113205359.556831-6-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The migrate_prep{_local} never fails, so it is pointless to have return
value and check the return value.
Link: https://lkml.kernel.org/r/20201113205359.556831-5-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The NUMA balancing skip shared exec base page. Since
CONFIG_READ_ONLY_THP_FOR_FS was introduced, there are probably shared exec
THP, so skip such THPs for NUMA balancing as well.
And Willy's regular filesystem THP support patches could create shared
exec THP wven without that config.
In addition, the page_is_file_lru() is used to tell if the page is file
cache or not, but it filters out shmem page. It sounds like a typical
usecase by putting executables in shmem to achieve performance gain via
using shmem-THP, so it sounds worth skipping migration for such case too.
Link: https://lkml.kernel.org/r/20201113205359.556831-4-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When unmap_and_move{_huge_page}() returns !-EAGAIN and
!MIGRATEPAGE_SUCCESS, the page would be put back to LRU or proper list if
it is non-LRU movable page. But, the callers always call
putback_movable_pages() to put the failed pages back later on, so it seems
not very efficient to put every single page back immediately, and the code
looks convoluted.
Put the failed page on a separate list, then splice the list to migrate
list when all pages are tried. It is the caller's responsibility to call
putback_movable_pages() to handle failures. This also makes the code
simpler and more readable.
After the change the rules are:
* Success: non hugetlb page will be freed, hugetlb page will be put
back
* -EAGAIN: stay on the from list
* -ENOMEM: stay on the from list
* Other errno: put on ret_pages list then splice to from list
The from list would be empty iff all pages are migrated successfully, it
was not so before. This has no impact to current existing callsites.
Link: https://lkml.kernel.org/r/20201113205359.556831-3-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm: misc migrate cleanup and improvement", v3.
This patch (of 5):
The commit 9f4e41f471 ("mm: refactor truncate_complete_page()")
refactored truncate_complete_page(), and it is not existed anymore,
correct the comment in vmscan and migrate to avoid confusion.
Link: https://lkml.kernel.org/r/20201113205359.556831-1-shy828301@gmail.com
Link: https://lkml.kernel.org/r/20201113205359.556831-2-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When migrating a zero page or pte_none() anonymous page to device private
memory, migrate_vma_setup() will initialize the src[] array with a NULL
PFN. This lets the device driver allocate device private memory and clear
it instead of DMAing a page of zeros over the device bus.
Since the source page didn't exist at the time, no struct page was locked
nor a migration PTE inserted into the CPU page tables. The actual PTE
insertion happens in migrate_vma_pages() when it tries to insert the
device private struct page PTE into the CPU page tables.
migrate_vma_pages() has to call the mmu notifiers again since another
device could fault on the same page before the page table locks are
acquired.
Allow device drivers to optimize the invalidation similar to
migrate_vma_setup() by calling mmu_notifier_range_init() which sets struct
mmu_notifier_range event type to MMU_NOTIFY_MIGRATE and the
migrate_pgmap_owner field.
Link: https://lkml.kernel.org/r/20201021191335.10916-1-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The word in the comment is misspelled, it should be "include".
Link: https://lkml.kernel.org/r/20201024114144.GA20552@lilong
Signed-off-by: Long Li <lonuxli.64@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>
Since commit 369ea8242c ("mm/rmap: update to new mmu_notifier semantic
v2"), the code to check the secondary MMU's page table access bit is
broken for !(TTU_IGNORE_ACCESS) because the page is unmapped from the
secondary MMU's page table before the check. More specifically for those
secondary MMUs which unmap the memory in
mmu_notifier_invalidate_range_start() like kvm.
However memory reclaim is the only user of !(TTU_IGNORE_ACCESS) or the
absence of TTU_IGNORE_ACCESS and it explicitly performs the page table
access check before trying to unmap the page. So, at worst the reclaim
will miss accesses in a very short window if we remove page table access
check in unmapping code.
There is an unintented consequence of !(TTU_IGNORE_ACCESS) for the memcg
reclaim. From memcg reclaim the page_referenced() only account the
accesses from the processes which are in the same memcg of the target page
but the unmapping code is considering accesses from all the processes, so,
decreasing the effectiveness of memcg reclaim.
The simplest solution is to always assume TTU_IGNORE_ACCESS in unmapping
code.
Link: https://lkml.kernel.org/r/20201104231928.1494083-1-shakeelb@google.com
Fixes: 369ea8242c ("mm/rmap: update to new mmu_notifier semantic v2")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
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>
Qian Cai reported the following BUG in [1]
LTP: starting move_pages12
BUG: unable to handle page fault for address: ffffffffffffffe0
...
RIP: 0010:anon_vma_interval_tree_iter_first+0xa2/0x170 avc_start_pgoff at mm/interval_tree.c:63
Call Trace:
rmap_walk_anon+0x141/0xa30 rmap_walk_anon at mm/rmap.c:1864
try_to_unmap+0x209/0x2d0 try_to_unmap at mm/rmap.c:1763
migrate_pages+0x1005/0x1fb0
move_pages_and_store_status.isra.47+0xd7/0x1a0
__x64_sys_move_pages+0xa5c/0x1100
do_syscall_64+0x5f/0x310
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Hugh Dickins diagnosed this as a migration bug caused by code introduced
to use i_mmap_rwsem for pmd sharing synchronization. Specifically, the
routine unmap_and_move_huge_page() is always passing the TTU_RMAP_LOCKED
flag to try_to_unmap() while holding i_mmap_rwsem. This is wrong for
anon pages as the anon_vma_lock should be held in this case. Further
analysis suggested that i_mmap_rwsem was not required to he held at all
when calling try_to_unmap for anon pages as an anon page could never be
part of a shared pmd mapping.
Discussion also revealed that the hack in hugetlb_page_mapping_lock_write
to drop page lock and acquire i_mmap_rwsem is wrong. There is no way to
keep mapping valid while dropping page lock.
This patch does the following:
- Do not take i_mmap_rwsem and set TTU_RMAP_LOCKED for anon pages when
calling try_to_unmap.
- Remove the hacky code in hugetlb_page_mapping_lock_write. The routine
will now simply do a 'trylock' while still holding the page lock. If
the trylock fails, it will return NULL. This could impact the
callers:
- migration calling code will receive -EAGAIN and retry up to the
hard coded limit (10).
- memory error code will treat the page as BUSY. This will force
killing (SIGKILL) instead of SIGBUS any mapping tasks.
Do note that this change in behavior only happens when there is a
race. None of the standard kernel testing suites actually hit this
race, but it is possible.
[1] https://lore.kernel.org/lkml/20200708012044.GC992@lca.pw/
[2] https://lore.kernel.org/linux-mm/alpine.LSU.2.11.2010071833100.2214@eggly.anvils/
Fixes: c0d0381ade ("hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization")
Reported-by: Qian Cai <cai@lca.pw>
Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201105195058.78401-1-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no need to check if this process has the right to modify the
specified process when they are same. And we could also skip the security
hook call if a process is modifying its own pages. Add helper function to
handle these.
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christopher Lameter <cl@linux.com>
Link: https://lkml.kernel.org/r/20200819083331.19012-1-linmiaohe@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch changes the way we set and handle in-use poisoned pages. Until
now, poisoned pages were released to the buddy allocator, trusting that
the checks that take place at allocation time would act as a safe net and
would skip that page.
This has proved to be wrong, as we got some pfn walkers out there, like
compaction, that all they care is the page to be in a buddy freelist.
Although this might not be the only user, having poisoned pages in the
buddy allocator seems a bad idea as we should only have free pages that
are ready and meant to be used as such.
Before explaining the taken approach, let us break down the kind of pages
we can soft offline.
- Anonymous THP (after the split, they end up being 4K pages)
- Hugetlb
- Order-0 pages (that can be either migrated or invalited)
* Normal pages (order-0 and anon-THP)
- If they are clean and unmapped page cache pages, we invalidate
then by means of invalidate_inode_page().
- If they are mapped/dirty, we do the isolate-and-migrate dance.
Either way, do not call put_page directly from those paths. Instead, we
keep the page and send it to page_handle_poison to perform the right
handling.
page_handle_poison sets the HWPoison flag and does the last put_page.
Down the chain, we placed a check for HWPoison page in
free_pages_prepare, that just skips any poisoned page, so those pages
do not end up in any pcplist/freelist.
After that, we set the refcount on the page to 1 and we increment
the poisoned pages counter.
If we see that the check in free_pages_prepare creates trouble, we can
always do what we do for free pages:
- wait until the page hits buddy's freelists
- take it off, and flag it
The downside of the above approach is that we could race with an
allocation, so by the time we want to take the page off the buddy, the
page has been already allocated so we cannot soft offline it.
But the user could always retry it.
* Hugetlb pages
- We isolate-and-migrate them
After the migration has been successful, we call dissolve_free_huge_page,
and we set HWPoison on the page if we succeed.
Hugetlb has a slightly different handling though.
While for non-hugetlb pages we cared about closing the race with an
allocation, doing so for hugetlb pages requires quite some additional
and intrusive code (we would need to hook in free_huge_page and some other
places).
So I decided to not make the code overly complicated and just fail
normally if the page we allocated in the meantime.
We can always build on top of this.
As a bonus, because of the way we handle now in-use pages, we no longer
need the put-as-isolation-migratetype dance, that was guarding for poisoned
pages to end up in pcplists.
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Aristeu Rozanski <aris@ruivo.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dmitry Yakunin <zeil@yandex-team.ru>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200922135650.1634-10-osalvador@suse.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Device public memory never had an in tree consumer and was removed in
commit 25b2995a35 ("mm: remove MEMORY_DEVICE_PUBLIC support"). Delete
the obsolete comment.
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20200827190735.12752-2-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The variable struct migrate_vma->cpages is only used in
migrate_vma_setup(). There is no need to decrement it in
migrate_vma_finalize() since it is never checked.
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20200827190735.12752-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'block-5.10-2020-10-12' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
- Series of merge handling cleanups (Baolin, Christoph)
- Series of blk-throttle fixes and cleanups (Baolin)
- Series cleaning up BDI, seperating the block device from the
backing_dev_info (Christoph)
- Removal of bdget() as a generic API (Christoph)
- Removal of blkdev_get() as a generic API (Christoph)
- Cleanup of is-partition checks (Christoph)
- Series reworking disk revalidation (Christoph)
- Series cleaning up bio flags (Christoph)
- bio crypt fixes (Eric)
- IO stats inflight tweak (Gabriel)
- blk-mq tags fixes (Hannes)
- Buffer invalidation fixes (Jan)
- Allow soft limits for zone append (Johannes)
- Shared tag set improvements (John, Kashyap)
- Allow IOPRIO_CLASS_RT for CAP_SYS_NICE (Khazhismel)
- DM no-wait support (Mike, Konstantin)
- Request allocation improvements (Ming)
- Allow md/dm/bcache to use IO stat helpers (Song)
- Series improving blk-iocost (Tejun)
- Various cleanups (Geert, Damien, Danny, Julia, Tetsuo, Tian, Wang,
Xianting, Yang, Yufen, yangerkun)
* tag 'block-5.10-2020-10-12' of git://git.kernel.dk/linux-block: (191 commits)
block: fix uapi blkzoned.h comments
blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue
blk-mq: get rid of the dead flush handle code path
block: get rid of unnecessary local variable
block: fix comment and add lockdep assert
blk-mq: use helper function to test hw stopped
block: use helper function to test queue register
block: remove redundant mq check
block: invoke blk_mq_exit_sched no matter whether have .exit_sched
percpu_ref: don't refer to ref->data if it isn't allocated
block: ratelimit handle_bad_sector() message
blk-throttle: Re-use the throtl_set_slice_end()
blk-throttle: Open code __throtl_de/enqueue_tg()
blk-throttle: Move service tree validation out of the throtl_rb_first()
blk-throttle: Move the list operation after list validation
blk-throttle: Fix IO hang for a corner case
blk-throttle: Avoid tracking latency if low limit is invalid
blk-throttle: Avoid getting the current time if tg->last_finish_time is 0
blk-throttle: Remove a meaningless parameter for throtl_downgrade_state()
block: Remove redundant 'return' statement
...
PageTransHuge returns true for both thp and hugetlb, so thp stats was
counting both thp and hugetlb migrations. Exclude hugetlb migration by
setting is_thp variable right.
Clean up thp handling code too when we are there.
Fixes: 1a5bae25e3 ("mm/vmstat: add events for THP migration without split")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lkml.kernel.org/r/20200917210413.1462975-1-zi.yan@sent.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace the two negative flags that are always used together with a
single positive flag that indicates the writeback capability instead
of two related non-capabilities. Also remove the pointless wrappers
to just check the flag.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
hugetlbfs pages do not participate in memcg: so although they do find most
of migrate_page_states() useful, it would be better if they did not call
into mem_cgroup_migrate() - where Qian Cai reported that LTP's
move_pages12 triggers the warning in Alex Shi's prospective commit
"mm/memcg: warning on !memcg after readahead page charged".
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxch.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008301359460.5954@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The code to remove a migration PTE and replace it with a device private
PTE was not copying the soft dirty bit from the migration entry. This
could lead to page contents not being marked dirty when faulting the page
back from device private memory.
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-3-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/migrate: preserve soft dirty in remove_migration_pte()".
I happened to notice this from code inspection after seeing Alistair
Popple's patch ("mm/rmap: Fixup copying of soft dirty and uffd ptes").
This patch (of 2):
The check for is_zone_device_page() and is_device_private_page() is
unnecessary since the latter is sufficient to determine if the page is a
device private page. Simplify the code for easier reading.
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-1-rcampbell@nvidia.com
Link: https://lkml.kernel.org/r/20200831212222.22409-2-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During memory migration a pte is temporarily replaced with a migration
swap pte. Some pte bits from the existing mapping such as the soft-dirty
and uffd write-protect bits are preserved by copying these to the
temporary migration swap pte.
However these bits are not stored at the same location for swap and
non-swap ptes. Therefore testing these bits requires using the
appropriate helper function for the given pte type.
Unfortunately several code locations were found where the wrong helper
function is being used to test soft_dirty and uffd_wp bits which leads to
them getting incorrectly set or cleared during page-migration.
Fix these by using the correct tests based on pte type.
Fixes: a5430dda8a ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Fixes: 8c3328f1f3 ("mm/migrate: migrate_vma() unmap page from vma while collecting pages")
Fixes: f45ec5ff16 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Alistair Popple <alistair@popple.id.au>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200825064232.10023-2-alistair@popple.id.au
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit f45ec5ff16 ("userfaultfd: wp: support swap and page migration")
introduced support for tracking the uffd wp bit during page migration.
However the non-swap PTE variant was used to set the flag for zone device
private pages which are a type of swap page.
This leads to corruption of the swap offset if the original PTE has the
uffd_wp flag set.
Fixes: f45ec5ff16 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: https://lkml.kernel.org/r/20200825064232.10023-1-alistair@popple.id.au
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The thp prefix is more frequently used than hpage and we should be
consistent between the various functions.
[akpm@linux-foundation.org: fix mm/migrate.c]
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20200629151959.15779-6-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a well-defined migration target allocation callback. Use it.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-7-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are some similar functions for migration target allocation. Since
there is no fundamental difference, it's better to keep just one rather
than keeping all variants. This patch implements base migration target
allocation function. In the following patches, variants will be converted
to use this function.
Changes should be mechanical, but, unfortunately, there are some
differences. First, some callers' nodemask is assgined to NULL since NULL
nodemask will be considered as all available nodes, that is,
&node_states[N_MEMORY]. Second, for hugetlb page allocation, gfp_mask is
redefined as regular hugetlb allocation gfp_mask plus __GFP_THISNODE if
user provided gfp_mask has it. This is because future caller of this
function requires to set this node constaint. Lastly, if provided nodeid
is NUMA_NO_NODE, nodeid is set up to the node where migration source
lives. It helps to remove simple wrappers for setting up the nodeid.
Note that PageHighmem() call in previous function is changed to open-code
"is_highmem_idx()" since it provides more readability.
[akpm@linux-foundation.org: tweak patch title, per Vlastimil]
[akpm@linux-foundation.org: fix typo in comment]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-6-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
new_page_nodemask is a migration callback and it tries to use a common gfp
flags for the target page allocation whether it is a base page or a THP.
The later only adds GFP_TRANSHUGE to the given mask. This results in the
allocation being slightly more aggressive than necessary because the
resulting gfp mask will contain also __GFP_RECLAIM_KSWAPD. THP
allocations usually exclude this flag to reduce over eager background
reclaim during a high THP allocation load which has been seen during large
mmaps initialization. There is no indication that this is a problem for
migration as well but theoretically the same might happen when migrating
large mappings to a different node. Make the migration callback
consistent with regular THP allocations.
[akpm@linux-foundation.org: fix comment typo, per Vlastimil]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-5-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no difference between two migration callback functions,
alloc_huge_page_node() and alloc_huge_page_nodemask(), except
__GFP_THISNODE handling. It's redundant to have two almost similar
functions in order to handle this flag. So, this patch tries to remove
one by introducing a new argument, gfp_mask, to
alloc_huge_page_nodemask().
After introducing gfp_mask argument, it's caller's job to provide correct
gfp_mask. So, every callsites for alloc_huge_page_nodemask() are changed
to provide gfp_mask.
Note that it's safe to remove a node id check in alloc_huge_page_node()
since there is no caller passing NUMA_NO_NODE as a node id.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-4-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's not performance sensitive function. Move it to .c. This is a
preparation step for future change.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/1594622517-20681-3-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Drop the repeated word "and".
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Link: http://lkml.kernel.org/r/20200801173822.14973-8-rdunlap@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add following new vmstat events which will help in validating THP
migration without split. Statistics reported through these new VM events
will help in performance debugging.
1. THP_MIGRATION_SUCCESS
2. THP_MIGRATION_FAILURE
3. THP_MIGRATION_SPLIT
In addition, these new events also update normal page migration statistics
appropriately via PGMIGRATE_SUCCESS and PGMIGRATE_FAILURE. While here,
this updates current trace event 'mm_migrate_pages' to accommodate now
available THP statistics.
[akpm@linux-foundation.org: s/hpage_nr_pages/thp_nr_pages/]
[ziy@nvidia.com: v2]
Link: http://lkml.kernel.org/r/C5E3C65C-8253-4638-9D3C-71A61858BB8B@nvidia.com
[anshuman.khandual@arm.com: s/thp_nr_pages/hpage_nr_pages/]
Link: http://lkml.kernel.org/r/1594287583-16568-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Link: http://lkml.kernel.org/r/1594080415-27924-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/migrate: optimize migrate_vma_setup() for holes".
A simple optimization for migrate_vma_*() when the source vma is not an
anonymous vma and a new test case to exercise it.
This patch (of 2):
When migrating system memory to device private memory, if the source
address range is a valid VMA range and there is no memory or a zero page,
the source PFN array is marked as valid but with no PFN.
This lets the device driver allocate private memory and clear it, then
insert the new device private struct page into the CPU's page tables when
migrate_vma_pages() is called. migrate_vma_pages() only inserts the new
page if the VMA is an anonymous range.
There is no point in telling the device driver to allocate device private
memory and then not migrate the page. Instead, mark the source PFN array
entries as not migrating to avoid this overhead.
[rcampbell@nvidia.com: v2]
Link: http://lkml.kernel.org/r/20200710194840.7602-2-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: "Bharata B Rao" <bharata@linux.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200710194840.7602-1-rcampbell@nvidia.com
Link: http://lkml.kernel.org/r/20200709165711.26584-1-rcampbell@nvidia.com
Link: http://lkml.kernel.org/r/20200709165711.26584-2-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In current implementation, newly created or swap-in anonymous page is
started on active list. Growing active list results in rebalancing
active/inactive list so old pages on active list are demoted to inactive
list. Hence, the page on active list isn't protected at all.
Following is an example of this situation.
Assume that 50 hot pages on active list. Numbers denote the number of
pages on active/inactive list (active | inactive).
1. 50 hot pages on active list
50(h) | 0
2. workload: 50 newly created (used-once) pages
50(uo) | 50(h)
3. workload: another 50 newly created (used-once) pages
50(uo) | 50(uo), swap-out 50(h)
This patch tries to fix this issue. Like as file LRU, newly created or
swap-in anonymous pages will be inserted to the inactive list. They are
promoted to active list if enough reference happens. This simple
modification changes the above example as following.
1. 50 hot pages on active list
50(h) | 0
2. workload: 50 newly created (used-once) pages
50(h) | 50(uo)
3. workload: another 50 newly created (used-once) pages
50(h) | 50(uo), swap-out 50(uo)
As you can see, hot pages on active list would be protected.
Note that, this implementation has a drawback that the page cannot be
promoted and will be swapped-out if re-access interval is greater than the
size of inactive list but less than the size of total(active+inactive).
To solve this potential issue, following patch will apply workingset
detection similar to the one that's already applied to file LRU.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Link: http://lkml.kernel.org/r/1595490560-15117-3-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On x86_64, when CONFIG_MMU_NOTIFIER is not set/enabled, there is a
compiler error:
mm/migrate.c: In function 'migrate_vma_collect':
mm/migrate.c:2481:7: error: 'struct mmu_notifier_range' has no member named 'migrate_pgmap_owner'
range.migrate_pgmap_owner = migrate->pgmap_owner;
^
Fixes: 998427b3ad ("mm/notifier: add migration invalidation type")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Jason Gunthorpe" <jgg@mellanox.com>
Link: http://lkml.kernel.org/r/20200806193353.7124-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This series adds reporting of the page table order from hmm_range_fault()
and some optimization of migrate_vma():
- Report the size of the page table mapping out of hmm_range_fault(). This
makes it easier to establish a large/huge/etc mapping in the device's
page table.
- Allow devices to ignore the invalidations during migration in cases
where the migration is not going to change pages. For instance migrating
pages to a device does not require the device to invalidate pages
already in the device.
- Update nouveau and hmm_tests to use the above
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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:
"Ralph has been working on nouveau's use of hmm_range_fault() and
migrate_vma() which resulted in this small series. It adds reporting
of the page table order from hmm_range_fault() and some optimization
of migrate_vma():
- Report the size of the page table mapping out of hmm_range_fault().
This makes it easier to establish a large/huge/etc mapping in the
device's page table.
- Allow devices to ignore the invalidations during migration in cases
where the migration is not going to change pages.
For instance migrating pages to a device does not require the
device to invalidate pages already in the device.
- Update nouveau and hmm_tests to use the above"
* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
mm/hmm/test: use the new migration invalidation
nouveau/svm: use the new migration invalidation
mm/notifier: add migration invalidation type
mm/migrate: add a flags parameter to migrate_vma
nouveau: fix storing invalid ptes
nouveau/hmm: support mapping large sysmem pages
nouveau: fix mapping 2MB sysmem pages
nouveau/hmm: fault one page at a time
mm/hmm: add tests for hmm_pfn_to_map_order()
mm/hmm: provide the page mapping order in hmm_range_fault()
Currently migrate_vma_setup() calls mmu_notifier_invalidate_range_start()
which flushes all device private page mappings whether or not a page is
being migrated to/from device private memory.
In order to not disrupt device mappings that are not being migrated, shift
the responsibility for clearing device private mappings to the device
driver and leave CPU page table unmapping handled by
migrate_vma_setup().
To support this, the caller of migrate_vma_setup() should always set
struct migrate_vma::pgmap_owner to a non NULL value that matches the
device private page->pgmap->owner. This value is then passed to the struct
mmu_notifier_range with a new event type which the driver's invalidation
function can use to avoid device MMU invalidations.
Link: https://lore.kernel.org/r/20200723223004.9586-4-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
The src_owner field in struct migrate_vma is being used for two purposes,
it acts as a selection filter for which types of pages are to be migrated
and it identifies device private pages owned by the caller.
Split this into separate parameters so the src_owner field can be used
just to identify device private pages owned by the caller of
migrate_vma_setup().
Rename the src_owner field to pgmap_owner to reflect it is now used only
to identify which device private pages to migrate.
Link: https://lore.kernel.org/r/20200723223004.9586-3-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
I realize that we fairly recently raised it to 4.8, but the fact is, 4.9
is a much better minimum version to target.
We have a number of workarounds for actual bugs in pre-4.9 gcc versions
(including things like internal compiler errors on ARM), but we also
have some syntactic workarounds for lacking features.
In particular, raising the minimum to 4.9 means that we can now just
assume _Generic() exists, which is likely the much better replacement
for a lot of very convoluted built-time magic with conditionals on
sizeof and/or __builtin_choose_expr() with same_type() etc.
Using _Generic also means that you will need to have a very recent
version of 'sparse', but thats easy to build yourself, and much less of
a hassle than some old gcc version can be.
The latest (in a long string) of reasons for minimum compiler version
upgrades was commit 5435f73d5c ("efi/x86: Fix build with gcc 4").
Ard points out that RHEL 7 uses gcc-4.8, but the people who stay back on
old RHEL versions persumably also don't build their own kernels anyway.
And maybe they should cross-built or just have a little side affair with
a newer compiler?
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Swapin faults were the last event to charge pages after they had already
been put on the LRU list. Now that we charge directly on swapin, the
lrucare portion of the charge code is unused.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-19-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the page->mapping requirement gone from memcg, we can charge anon and
file-thp pages in one single step, right after they're allocated.
This removes two out of three API calls - especially the tricky commit
step that needed to happen at just the right time between when the page is
"set up" and when it's "published" - somewhat vague and fluid concepts
that varied by page type. All we need is a freshly allocated page and a
memcg context to charge.
v2: prevent double charges on pre-allocated hugepages in khugepaged
[hannes@cmpxchg.org: Fix crash - *hpage could be ERR_PTR instead of NULL]
Link: http://lkml.kernel.org/r/20200512215813.GA487759@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/20200508183105.225460-13-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memcg maintains a private MEMCG_RSS counter. This divergence from the
generic VM accounting means unnecessary code overhead, and creates a
dependency for memcg that page->mapping is set up at the time of charging,
so that page types can be told apart.
Convert the generic accounting sites to mod_lruvec_page_state and friends
to maintain the per-cgroup vmstat counter of NR_ANON_MAPPED. We use
lock_page_memcg() to stabilize page->mem_cgroup during rmap changes, the
same way we do for NR_FILE_MAPPED.
With the previous patch removing MEMCG_CACHE and the private NR_SHMEM
counter, this patch finally eliminates the need to have page->mapping set
up at charge time. However, we need to have page->mem_cgroup set up by
the time rmap runs and does the accounting, so switch the commit and the
rmap callbacks around.
v2: fix temporary accounting bug by switching rmap<->commit (Joonsoo)
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-11-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memcg maintains private MEMCG_CACHE and NR_SHMEM counters. This
divergence from the generic VM accounting means unnecessary code overhead,
and creates a dependency for memcg that page->mapping is set up at the
time of charging, so that page types can be told apart.
Convert the generic accounting sites to mod_lruvec_page_state and friends
to maintain the per-cgroup vmstat counters of NR_FILE_PAGES and NR_SHMEM.
The page is already locked in these places, so page->mem_cgroup is stable;
we only need minimal tweaks of two mem_cgroup_migrate() calls to ensure
it's set up in time.
Then replace MEMCG_CACHE with NR_FILE_PAGES and delete the private
NR_SHMEM accounting sites.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-10-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memcg charging API carries a boolean @compound parameter that tells
whether the page we're dealing with is a hugepage.
mem_cgroup_commit_charge() has another boolean @lrucare that indicates
whether the page needs LRU locking or not while charging. The majority of
callsites know those parameters at compile time, which results in a lot of
naked "false, false" argument lists. This makes for cryptic code and is a
breeding ground for subtle mistakes.
Thankfully, the huge page state can be inferred from the page itself and
doesn't need to be passed along. This is safe because charging completes
before the page is published and somebody may split it.
Simplify the callsites by removing @compound, and let memcg infer the
state by using hpage_nr_pages() unconditionally. That function does
PageTransHuge() to identify huge pages, which also helpfully asserts that
nobody passes in tail pages by accident.
The following patches will introduce a new charging API, best not to carry
over unnecessary weight.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-4-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Just finished bisecting mmotm, to find why a test which used to take
four minutes now took more than an hour: the __buffer_migrate_page()
cleanup left behind a get_page() which attach_page_private() now does.
Fixes: cd0f371544 ("mm/migrate.c: call detach_page_private to cleanup code")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We can cleanup code a little by call detach_page_private here.
[akpm@linux-foundation.org: use attach_page_private(), per Dave]
http://lkml.kernel.org/r/20200521225220.GV2005@dread.disaster.area
[akpm@linux-foundation.org: clear PagePrivate]
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Link: http://lkml.kernel.org/r/20200519214049.15179-1-guoqing.jiang@cloud.ionos.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement the new readahead aop and convert all callers (block_dev,
exfat, ext2, fat, gfs2, hpfs, isofs, jfs, nilfs2, ocfs2, omfs, qnx6,
reiserfs & udf).
The callers are all trivial except for GFS2 & OCFS2.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com> # ocfs2
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> # ocfs2
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Link: http://lkml.kernel.org/r/20200414150233.24495-17-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For either swap and page migration, we all use the bit 2 of the entry to
identify whether this entry is uffd write-protected. It plays a similar
role as the existing soft dirty bit in swap entries but only for keeping
the uffd-wp tracking for a specific PTE/PMD.
Something special here is that when we want to recover the uffd-wp bit
from a swap/migration entry to the PTE bit we'll also need to take care of
the _PAGE_RW bit and make sure it's cleared, otherwise even with the
_PAGE_UFFD_WP bit we can't trap it at all.
In change_pte_range() we do nothing for uffd if the PTE is a swap entry.
That can lead to data mismatch if the page that we are going to write
protect is swapped out when sending the UFFDIO_WRITEPROTECT. This patch
also applies/removes the uffd-wp bit even for the swap entries.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Link: http://lkml.kernel.org/r/20200220163112.11409-11-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some comments for MADV_FREE is revised and added to help people understand
the MADV_FREE code, especially the page flag, PG_swapbacked. This makes
page_is_file_cache() isn't consistent with its comments. So the function
is renamed to page_is_file_lru() to make them consistent again. All these
are put in one patch as one logical change.
Suggested-by: David Hildenbrand <david@redhat.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@kernel.org>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200317100342.2730705-1-ying.huang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the migration code doesn't migrate PG_readahead flag.
Theoretically this would incur slight performance loss as the application
might have to ramp its readahead back up again. Even though such problem
happens, it might be hidden by something else since migration is typically
triggered by compaction and NUMA balancing, any of which should be more
noticeable.
Migrate the flag after end_page_writeback() since it may clear PG_reclaim
flag, which is the same bit as PG_readahead, for the new page.
[akpm@linux-foundation.org: tweak comment]
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Link: http://lkml.kernel.org/r/1581640185-95731-1-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It can currently happen that we store the status of a page twice:
* Once we detect that it is already on the target node
* Once we moved a bunch of pages, and a page that's already on the
target node is contained in the current interval.
Let's simplify the code and always call do_move_pages_to_node() in case we
did not queue a page for migration. Note that pages that are already on
the target node are not added to the pagelist and are, therefore, ignored
by do_move_pages_to_node() - there is no functional change.
The status of such a page is now only stored once.
[david@redhat.com rephrase changelog]
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/20200214003017.25558-5-richardw.yang@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When pagelist is empty, it is not necessary to do the move and store.
Also it consolidate the empty list check in one place.
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/20200214003017.25558-4-richardw.yang@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Usually, do_move_pages_to_node() and store_status() are used in
combination. We have three similar call sites.
Let's provide a wrapper for both function calls -
move_pages_and_store_status - to make the calling code easier to maintain
and fix (as noted by Yang Shi, the return value handling of
do_move_pages_to_node() has a flaw).
[david@redhat.com rephrase changelog]
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/20200214003017.25558-3-richardw.yang@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "cleanup on do_pages_move()", v5.
The logic in do_pages_move() is a little mess for audience to read and has
some potential error on handling the return value. Especially there are
three calls on do_move_pages_to_node() and store_status() with almost the
same form.
This patch set tries to make the code a little friendly for audience by
consolidate the calls.
This patch (of 4):
At this point, we always have i >= start. If i == start, store_status()
will return 0. So we can drop the check for i > start.
[david@redhat.com rephrase changelog]
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/20200214003017.25558-2-richardw.yang@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge updates from Andrew Morton:
"A large amount of MM, plenty more to come.
Subsystems affected by this patch series:
- tools
- kthread
- kbuild
- scripts
- ocfs2
- vfs
- mm: slub, kmemleak, pagecache, gup, swap, memcg, pagemap, mremap,
sparsemem, kasan, pagealloc, vmscan, compaction, mempolicy,
hugetlbfs, hugetlb"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (155 commits)
include/linux/huge_mm.h: check PageTail in hpage_nr_pages even when !THP
mm/hugetlb: fix build failure with HUGETLB_PAGE but not HUGEBTLBFS
selftests/vm: fix map_hugetlb length used for testing read and write
mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge()
mm/hugetlb.c: clean code by removing unnecessary initialization
hugetlb_cgroup: add hugetlb_cgroup reservation docs
hugetlb_cgroup: add hugetlb_cgroup reservation tests
hugetlb: support file_region coalescing again
hugetlb_cgroup: support noreserve mappings
hugetlb_cgroup: add accounting for shared mappings
hugetlb: disable region_add file_region coalescing
hugetlb_cgroup: add reservation accounting for private mappings
mm/hugetlb_cgroup: fix hugetlb_cgroup migration
hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations
hugetlb_cgroup: add hugetlb_cgroup reservation counter
hugetlbfs: Use i_mmap_rwsem to address page fault/truncate race
hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization
mm/memblock.c: remove redundant assignment to variable max_addr
mm: mempolicy: require at least one nodeid for MPOL_PREFERRED
mm: mempolicy: use VM_BUG_ON_VMA in queue_pages_test_walk()
...
Patch series "hugetlbfs: use i_mmap_rwsem for more synchronization", v2.
While discussing the issue with huge_pte_offset [1], I remembered that
there were more outstanding hugetlb races. These issues are:
1) For shared pmds, huge PTE pointers returned by huge_pte_alloc can become
invalid via a call to huge_pmd_unshare by another thread.
2) hugetlbfs page faults can race with truncation causing invalid global
reserve counts and state.
A previous attempt was made to use i_mmap_rwsem in this manner as
described at [2]. However, those patches were reverted starting with [3]
due to locking issues.
To effectively use i_mmap_rwsem to address the above issues it needs to be
held (in read mode) during page fault processing. However, during fault
processing we need to lock the page we will be adding. Lock ordering
requires we take page lock before i_mmap_rwsem. Waiting until after
taking the page lock is too late in the fault process for the
synchronization we want to do.
To address this lock ordering issue, the following patches change the lock
ordering for hugetlb pages. This is not too invasive as hugetlbfs
processing is done separate from core mm in many places. However, I don't
really like this idea. Much ugliness is contained in the new routine
hugetlb_page_mapping_lock_write() of patch 1.
The only other way I can think of to address these issues is by catching
all the races. After catching a race, cleanup, backout, retry ... etc,
as needed. This can get really ugly, especially for huge page
reservations. At one time, I started writing some of the reservation
backout code for page faults and it got so ugly and complicated I went
down the path of adding synchronization to avoid the races. Any other
suggestions would be welcome.
[1] https://lore.kernel.org/linux-mm/1582342427-230392-1-git-send-email-longpeng2@huawei.com/
[2] https://lore.kernel.org/linux-mm/20181222223013.22193-1-mike.kravetz@oracle.com/
[3] https://lore.kernel.org/linux-mm/20190103235452.29335-1-mike.kravetz@oracle.com
[4] https://lore.kernel.org/linux-mm/1584028670.7365.182.camel@lca.pw/
[5] https://lore.kernel.org/lkml/20200312183142.108df9ac@canb.auug.org.au/
This patch (of 2):
While looking at BUGs associated with invalid huge page map counts, it was
discovered and observed that a huge pte pointer could become 'invalid' and
point to another task's page table. Consider the following:
A task takes a page fault on a shared hugetlbfs file and calls
huge_pte_alloc to get a ptep. Suppose the returned ptep points to a
shared pmd.
Now, another task truncates the hugetlbfs file. As part of truncation, it
unmaps everyone who has the file mapped. If the range being truncated is
covered by a shared pmd, huge_pmd_unshare will be called. For all but the
last user of the shared pmd, huge_pmd_unshare will clear the pud pointing
to the pmd. If the task in the middle of the page fault is not the last
user, the ptep returned by huge_pte_alloc now points to another task's
page table or worse. This leads to bad things such as incorrect page
map/reference counts or invalid memory references.
To fix, expand the use of i_mmap_rwsem as follows:
- i_mmap_rwsem is held in read mode whenever huge_pmd_share is called.
huge_pmd_share is only called via huge_pte_alloc, so callers of
huge_pte_alloc take i_mmap_rwsem before calling. In addition, callers
of huge_pte_alloc continue to hold the semaphore until finished with
the ptep.
- i_mmap_rwsem is held in write mode whenever huge_pmd_unshare is called.
One problem with this scheme is that it requires taking i_mmap_rwsem
before taking the page lock during page faults. This is not the order
specified in the rest of mm code. Handling of hugetlbfs pages is mostly
isolated today. Therefore, we use this alternative locking order for
PageHuge() pages.
mapping->i_mmap_rwsem
hugetlb_fault_mutex (hugetlbfs specific page fault mutex)
page->flags PG_locked (lock_page)
To help with lock ordering issues, hugetlb_page_mapping_lock_write() is
introduced to write lock the i_mmap_rwsem associated with a page.
In most cases it is easy to get address_space via vma->vm_file->f_mapping.
However, in the case of migration or memory errors for anon pages we do
not have an associated vma. A new routine _get_hugetlb_page_mapping()
will use anon_vma to get address_space in these cases.
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Link: http://lkml.kernel.org/r/20200316205756.146666-2-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new src_owner field to struct migrate_vma. If the field is set,
only device private pages with page->pgmap->owner equal to that field are
migrated. If the field is not set only "normal" pages are migrated.
Fixes: df6ad69838 ("mm/device-public-memory: device memory cache coherent with CPU")
Link: https://lore.kernel.org/r/20200316193216.920734-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Tested-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Matthew Wilcox (Oracle)