When calculating pages in a node, for each zone in that node, we will
have
zone_spanned_pages_in_node
--> get_pfn_range_for_nid
zone_absent_pages_in_node
--> get_pfn_range_for_nid
That is to say, we call the get_pfn_range_for_nid to get start_pfn and
end_pfn of the node for MAX_NR_ZONES * 2 times. And this is totally
unnecessary if we call the get_pfn_range_for_nid before
zone_*_pages_in_node add two extra arguments node_start_pfn and
node_end_pfn for zone_*_pages_in_node, then we can remove the
get_pfn_range_in_node in zone_*_pages_in_node.
[akpm@linux-foundation.org: make definitions more readable]
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove struct mem_cgroup_lru_info and fold its single member, the
variably sized nodeinfo[0], directly into struct mem_cgroup. This
should make it more obvious why it has to be the last member there.
Also move the comment that's above that special last member below it, so
it is more visible to somebody that considers appending to the struct
mem_cgroup.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is very similar to commit 84d96d8976 ("mm: madvise:
complete input validation before taking lock"): perform some basic
validation of the input to mremap() before taking the
¤t->mm->mmap_sem lock.
This also makes the MREMAP_FIXED => MREMAP_MAYMOVE dependency slightly
more explicit.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Give s_next and s_stop slab-specific names instead of exporting
"s_next" and "s_stop".
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
While doing some code inspection, I noticed that the slob constructor
method can be called with a NULL pointer. If memory is tight and slob
fails to allocate with slob_alloc() or slob_new_pages() it still calls
the ctor() method with a NULL pointer. Looking at the first ctor()
method I found, I noticed that it can not handle a NULL pointer (I'm
sure others probably can't either):
static void sighand_ctor(void *data)
{
struct sighand_struct *sighand = data;
spin_lock_init(&sighand->siglock);
init_waitqueue_head(&sighand->signalfd_wqh);
}
The solution is to only call the ctor() method if allocation succeeded.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
CPU partial support can introduce level of indeterminism that is not
wanted in certain context (like a realtime kernel). Make it
configurable.
This patch is based on Christoph Lameter's "slub: Make cpu partial slab
support configurable V2".
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Some architectures (e.g. powerpc built with CONFIG_PPC_256K_PAGES=y
CONFIG_FORCE_MAX_ZONEORDER=11) get PAGE_SHIFT + MAX_ORDER > 26.
In 3.10 kernels, CONFIG_LOCKDEP=y with PAGE_SHIFT + MAX_ORDER > 26 makes
init_lock_keys() dereference beyond kmalloc_caches[26].
This leads to an unbootable system (kernel panic at initializing SLAB)
if one of kmalloc_caches[26...PAGE_SHIFT+MAX_ORDER-1] is not NULL.
Fix this by making sure that init_lock_keys() does not dereference beyond
kmalloc_caches[26] arrays.
Signed-off-by: Christoph Lameter <cl@linux.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-Love.SAKURA.ne.jp>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: <stable@vger.kernel.org> [3.10.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
In free path, we don't check number of cpu_partial, so one slab can
be linked in cpu partial list even if cpu_partial is 0. To prevent this,
we should check number of cpu_partial in put_cpu_partial().
Acked-by: Christoph Lameeter <cl@linux.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Use existing interface node_nr_slabs and node_nr_objs to get
nr_slabs and nr_objs.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This patch remove unused nr_partials variable.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Slab have some tunables like limit, batchcount, and sharedfactor can be
tuned through function slabinfo_write. Commit (b7454ad3: mm/sl[au]b: Move
slabinfo processing to slab_common.c) uncorrectly change /proc/slabinfo
unwriteable for slab, this patch fix it by revert to original mode.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This patch shares s_next and s_stop between slab and slub.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
The drain_freelist is called to drain slabs_free lists for cache reap,
cache shrink, memory hotplug callback etc. The tofree parameter should
be the number of slab to free instead of the number of slab objects to
free.
This patch fix the callers that pass # of objects. Make sure they pass #
of slabs.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Pull trivial tree updates from Jiri Kosina:
"The usual stuff from trivial tree"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (34 commits)
treewide: relase -> release
Documentation/cgroups/memory.txt: fix stat file documentation
sysctl/net.txt: delete reference to obsolete 2.4.x kernel
spinlock_api_smp.h: fix preprocessor comments
treewide: Fix typo in printk
doc: device tree: clarify stuff in usage-model.txt.
open firmware: "/aliasas" -> "/aliases"
md: bcache: Fixed a typo with the word 'arithmetic'
irq/generic-chip: fix a few kernel-doc entries
frv: Convert use of typedef ctl_table to struct ctl_table
sgi: xpc: Convert use of typedef ctl_table to struct ctl_table
doc: clk: Fix incorrect wording
Documentation/arm/IXP4xx fix a typo
Documentation/networking/ieee802154 fix a typo
Documentation/DocBook/media/v4l fix a typo
Documentation/video4linux/si476x.txt fix a typo
Documentation/virtual/kvm/api.txt fix a typo
Documentation/early-userspace/README fix a typo
Documentation/video4linux/soc-camera.txt fix a typo
lguest: fix CONFIG_PAE -> CONFIG_x86_PAE in comment
...
Pull powerpc updates from Ben Herrenschmidt:
"This is the powerpc changes for the 3.11 merge window. In addition to
the usual bug fixes and small updates, the main highlights are:
- Support for transparent huge pages by Aneesh Kumar for 64-bit
server processors. This allows the use of 16M pages as transparent
huge pages on kernels compiled with a 64K base page size.
- Base VFIO support for KVM on power by Alexey Kardashevskiy
- Wiring up of our nvram to the pstore infrastructure, including
putting compressed oopses in there by Aruna Balakrishnaiah
- Move, rework and improve our "EEH" (basically PCI error handling
and recovery) infrastructure. It is no longer specific to pseries
but is now usable by the new "powernv" platform as well (no
hypervisor) by Gavin Shan.
- I fixed some bugs in our math-emu instruction decoding and made it
usable to emulate some optional FP instructions on processors with
hard FP that lack them (such as fsqrt on Freescale embedded
processors).
- Support for Power8 "Event Based Branch" facility by Michael
Ellerman. This facility allows what is basically "userspace
interrupts" for performance monitor events.
- A bunch of Transactional Memory vs. Signals bug fixes and HW
breakpoint/watchpoint fixes by Michael Neuling.
And more ... I appologize in advance if I've failed to highlight
something that somebody deemed worth it."
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (156 commits)
pstore: Add hsize argument in write_buf call of pstore_ftrace_call
powerpc/fsl: add MPIC timer wakeup support
powerpc/mpic: create mpic subsystem object
powerpc/mpic: add global timer support
powerpc/mpic: add irq_set_wake support
powerpc/85xx: enable coreint for all the 64bit boards
powerpc/8xx: Erroneous double irq_eoi() on CPM IRQ in MPC8xx
powerpc/fsl: Enable CONFIG_E1000E in mpc85xx_smp_defconfig
powerpc/mpic: Add get_version API both for internal and external use
powerpc: Handle both new style and old style reserve maps
powerpc/hw_brk: Fix off by one error when validating DAWR region end
powerpc/pseries: Support compression of oops text via pstore
powerpc/pseries: Re-organise the oops compression code
pstore: Pass header size in the pstore write callback
powerpc/powernv: Fix iommu initialization again
powerpc/pseries: Inform the hypervisor we are using EBB regs
powerpc/perf: Add power8 EBB support
powerpc/perf: Core EBB support for 64-bit book3s
powerpc/perf: Drop MMCRA from thread_struct
powerpc/perf: Don't enable if we have zero events
...
Merge first patch-bomb from Andrew Morton:
- various misc bits
- I'm been patchmonkeying ocfs2 for a while, as Joel and Mark have been
distracted. There has been quite a bit of activity.
- About half the MM queue
- Some backlight bits
- Various lib/ updates
- checkpatch updates
- zillions more little rtc patches
- ptrace
- signals
- exec
- procfs
- rapidio
- nbd
- aoe
- pps
- memstick
- tools/testing/selftests updates
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (445 commits)
tools/testing/selftests: don't assume the x bit is set on scripts
selftests: add .gitignore for kcmp
selftests: fix clean target in kcmp Makefile
selftests: add .gitignore for vm
selftests: add hugetlbfstest
self-test: fix make clean
selftests: exit 1 on failure
kernel/resource.c: remove the unneeded assignment in function __find_resource
aio: fix wrong comment in aio_complete()
drivers/w1/slaves/w1_ds2408.c: add magic sequence to disable P0 test mode
drivers/memstick/host/r592.c: convert to module_pci_driver
drivers/memstick/host/jmb38x_ms: convert to module_pci_driver
pps-gpio: add device-tree binding and support
drivers/pps/clients/pps-gpio.c: convert to module_platform_driver
drivers/pps/clients/pps-gpio.c: convert to devm_* helpers
drivers/parport/share.c: use kzalloc
Documentation/accounting/getdelays.c: avoid strncpy in accounting tool
aoe: update internal version number to v83
aoe: update copyright date
aoe: perform I/O completions in parallel
...
Calling dev_set_name with a single paramter causes it to be handled as a
format string. Many callers are passing potentially dynamic string
content, so use "%s" in those cases to avoid any potential accidents,
including wrappers like device_create*() and bdi_register().
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mem_cgroup_iter() is too hard to follow. Factor out the lockless reclaim
iterator loading and updating so it's easier to follow the big picture.
Also document the iterator invalidation mechanism a bit more extensively.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now this function is nowhere used, we can remove it directly.
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here we pass flags with only VM_ALLOC bit set, it is unnecessary to call
clear_vm_unlist to clear VM_UNLIST bit. So use setup_vmalloc_vm instead
of insert_vmalloc_vm.
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now for insert_vmalloc_vm, it only calls the two functions:
- setup_vmalloc_vm: fill vm_struct and vmap_area instances
- clear_vm_unlist: clear VM_UNLIST bit in vm_struct->flags
So in __get_vm_area_node(), if VM_UNLIST bit unset in flags, that is the
else branch here, we don't need to clear VM_UNLIST bit for vm->flags since
this bit is obviously not set. That is to say, we could only call
setup_vmalloc_vm instead of insert_vmalloc_vm here. And then we could
even remove the if test here.
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instead of leaving a hidden trap for the next person who comes along and
wants to add something to mem_section, add a big fat warning about it
needing to be a power-of-2, and insert a BUILD_BUG_ON() in sparse_init()
to catch mistakes.
Right now non-power-of-2 mem_sections cause a number of WARNs at boot
(which don't clearly point to the size of mem_section as an issue), but
the system limps on (temporarily, at least).
This is based upon Dave Hansen's earlier RFC where he ran into the same
issue:
"sparsemem: fix boot when SECTIONS_PER_ROOT is not power-of-2"
http://lkml.indiana.edu/hypermail/linux/kernel/1205.2/03077.html
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jiang Liu <liuj97@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now nobody makes use of free_all_bootmem_node(), kill it.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Yinghai Lu <yinghai@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now all references to num_physpages have been removed, so kill it.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce helper function mem_init_print_info() to simplify mem_init()
across different architectures, which also unifies the format and
information printed.
Function mem_init_print_info() calculates memory statistics information
without walking each page, so it should be a little faster on some
architectures.
Also introduce another helper get_num_physpages() to kill the global
variable num_physpages.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
zap_pte_range loops from @addr to @end. In the middle, if it runs out of
batching slots, TLB entries needs to be flushed for @start to @interim,
NOT @interim to @end.
Since ARC port doesn't use page free batching I can't test it myself but
this seems like the right thing to do.
Observed this when working on a fix for the issue at thread:
http://www.spinics.net/lists/linux-arch/msg21736.html
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As reported by https://bugzilla.kernel.org/show_bug.cgi?id=53501,
"MemTotal" from /proc/meminfo means memory pages managed by the buddy
system (managed_pages), but "MemTotal" from /sys/.../node/nodex/meminfo
means physical pages present (present_pages) within the NUMA node.
There's a difference between managed_pages and present_pages due to
bootmem allocator and reserved pages.
And Documentation/filesystems/proc.txt says
MemTotal: Total usable ram (i.e. physical ram minus a few reserved
bits and the kernel binary code)
So change /sys/.../node/nodex/meminfo to report available pages within
the node as "MemTotal".
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Reported-by: <sworddragon2@aol.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Concentrate code to modify totalram_pages into the mm core, so the arch
memory initialized code doesn't need to take care of it. With these
changes applied, only following functions from mm core modify global
variable totalram_pages: free_bootmem_late(), free_all_bootmem(),
free_all_bootmem_node(), adjust_managed_page_count().
With this patch applied, it will be much more easier for us to keep
totalram_pages and zone->managed_pages in consistence.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michel Lespinasse <walken@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Enhance adjust_managed_page_count() to adjust totalhigh_pages for
highmem pages. And change code which directly adjusts totalram_pages to
use adjust_managed_page_count() because it adjusts totalram_pages,
totalhigh_pages and zone->managed_pages altogether in a safe way.
Remove inc_totalhigh_pages() and dec_totalhigh_pages() from xen/balloon
driver bacause adjust_managed_page_count() has already adjusted
totalhigh_pages.
This patch also fixes two bugs:
1) enhances virtio_balloon driver to adjust totalhigh_pages when
reserve/unreserve pages.
2) enhance memory_hotplug.c to adjust totalhigh_pages when hot-removing
memory.
We still need to deal with modifications of totalram_pages in file
arch/powerpc/platforms/pseries/cmm.c, but need help from PPC experts.
[akpm@linux-foundation.org: remove ifdef, per Wanpeng Li, virtio_balloon.c cleanup, per Sergei]
[akpm@linux-foundation.org: export adjust_managed_page_count() to modules, for drivers/virtio/virtio_balloon.c]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In order to simpilify management of totalram_pages and
zone->managed_pages, make __free_pages_bootmem() only available at boot
time. With this change applied, __free_pages_bootmem() will only be
used by bootmem.c and nobootmem.c at boot time, so mark it as __init.
Other callers of __free_pages_bootmem() have been converted to use
free_reserved_page(), which handles totalram_pages and
zone->managed_pages in a safer way.
This patch also fix a bug in free_pagetable() for x86_64, which should
increase zone->managed_pages instead of zone->present_pages when freeing
reserved pages.
And now we have managed_pages_count_lock to protect totalram_pages and
zone->managed_pages, so remove the redundant ppb_lock lock in
put_page_bootmem(). This greatly simplifies the locking rules.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently lock_memory_hotplug()/unlock_memory_hotplug() are used to
protect totalram_pages and zone->managed_pages. Other than the memory
hotplug driver, totalram_pages and zone->managed_pages may also be
modified at runtime by other drivers, such as Xen balloon,
virtio_balloon etc. For those cases, memory hotplug lock is a little
too heavy, so introduce a dedicated lock to protect totalram_pages and
zone->managed_pages.
Now we have a simplified locking rules totalram_pages and
zone->managed_pages as:
1) no locking for read accesses because they are unsigned long.
2) no locking for write accesses at boot time in single-threaded context.
3) serialize write accesses at runtime by acquiring the dedicated
managed_page_count_lock.
Also adjust zone->managed_pages when freeing reserved pages into the
buddy system, to keep totalram_pages and zone->managed_pages in
consistence.
[akpm@linux-foundation.org: don't export adjust_managed_page_count to modules (for now)]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit "mm: introduce new field 'managed_pages' to struct zone" assumes
that all highmem pages will be freed into the buddy system by function
mem_init(). But that's not always true, some architectures may reserve
some highmem pages during boot. For example PPC may allocate highmem
pages for giagant HugeTLB pages, and several architectures have code to
check PageReserved flag to exclude highmem pages allocated during boot
when freeing highmem pages into the buddy system.
So treat highmem pages in the same way as normal pages, that is to:
1) reset zone->managed_pages to zero in mem_init().
2) recalculate managed_pages when freeing pages into the buddy system.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Address more review comments from last round of code review.
1) Enhance free_reserved_area() to support poisoning freed memory with
pattern '0'. This could be used to get rid of poison_init_mem()
on ARM64.
2) A previous patch has disabled memory poison for initmem on s390
by mistake, so restore to the original behavior.
3) Remove redundant PAGE_ALIGN() when calling free_reserved_area().
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michel Lespinasse <walken@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change signature of free_reserved_area() according to Russell King's
suggestion to fix following build warnings:
arch/arm/mm/init.c: In function 'mem_init':
arch/arm/mm/init.c:603:2: warning: passing argument 1 of 'free_reserved_area' makes integer from pointer without a cast [enabled by default]
free_reserved_area(__va(PHYS_PFN_OFFSET), swapper_pg_dir, 0, NULL);
^
In file included from include/linux/mman.h:4:0,
from arch/arm/mm/init.c:15:
include/linux/mm.h:1301:22: note: expected 'long unsigned int' but argument is of type 'void *'
extern unsigned long free_reserved_area(unsigned long start, unsigned long end,
mm/page_alloc.c: In function 'free_reserved_area':
>> mm/page_alloc.c:5134:3: warning: passing argument 1 of 'virt_to_phys' makes pointer from integer without a cast [enabled by default]
In file included from arch/mips/include/asm/page.h:49:0,
from include/linux/mmzone.h:20,
from include/linux/gfp.h:4,
from include/linux/mm.h:8,
from mm/page_alloc.c:18:
arch/mips/include/asm/io.h:119:29: note: expected 'const volatile void *' but argument is of type 'long unsigned int'
mm/page_alloc.c: In function 'free_area_init_nodes':
mm/page_alloc.c:5030:34: warning: array subscript is below array bounds [-Warray-bounds]
Also address some minor code review comments.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <sworddragon2@aol.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michel Lespinasse <walken@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Considering the use cases where the swap device supports discard:
a) and can do it quickly;
b) but it's slow to do in small granularities (or concurrent with other
I/O);
c) but the implementation is so horrendous that you don't even want to
send one down;
And assuming that the sysadmin considers it useful to send the discards down
at all, we would (probably) want the following solutions:
i. do the fine-grained discards for freed swap pages, if device is
capable of doing so optimally;
ii. do single-time (batched) swap area discards, either at swapon
or via something like fstrim (not implemented yet);
iii. allow doing both single-time and fine-grained discards; or
iv. turn it off completely (default behavior)
As implemented today, one can only enable/disable discards for swap, but
one cannot select, for instance, solution (ii) on a swap device like (b)
even though the single-time discard is regarded to be interesting, or
necessary to the workload because it would imply (1), and the device is
not capable of performing it optimally.
This patch addresses the scenario depicted above by introducing a way to
ensure the (probably) wanted solutions (i, ii, iii and iv) can be flexibly
flagged through swapon(8) to allow a sysadmin to select the best suitable
swap discard policy accordingly to system constraints.
This patch introduces SWAP_FLAG_DISCARD_PAGES and SWAP_FLAG_DISCARD_ONCE
new flags to allow more flexibe swap discard policies being flagged
through swapon(8). The default behavior is to keep both single-time, or
batched, area discards (SWAP_FLAG_DISCARD_ONCE) and fine-grained discards
for page-clusters (SWAP_FLAG_DISCARD_PAGES) enabled, in order to keep
consistentcy with older kernel behavior, as well as maintain compatibility
with older swapon(8). However, through the new introduced flags the best
suitable discard policy can be selected accordingly to any given swap
device constraint.
[akpm@linux-foundation.org: tweak comments]
Signed-off-by: Rafael Aquini <aquini@redhat.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the per cpu counter's batch size for memory accounting is
configured as twice the number of cpus in the system. However, for
system with very large memory, it is more appropriate to make it
proportional to the memory size per cpu in the system.
For example, for a x86_64 system with 64 cpus and 128 GB of memory, the
batch size is only 2*64 pages (0.5 MB). So any memory accounting
changes of more than 0.5MB will overflow the per cpu counter into the
global counter. Instead, for the new scheme, the batch size is
configured to be 0.4% of the memory/cpu = 8MB (128 GB/64 /256), which is
more inline with the memory size.
I've done a repeated brk test of 800KB (from will-it-scale test suite)
with 80 concurrent processes on a 4 socket Westmere machine with a total
of 40 cores. Without the patch, about 80% of cpu is spent on spin-lock
contention within the vm_committed_as counter. With the patch, there's
a 73x speedup on the benchmark and the lock contention drops off almost
entirely.
[akpm@linux-foundation.org: fix section mismatch]
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the already existing interface huge_page_shift instead of h->order +
PAGE_SHIFT.
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During early boot-up, iomem_resource is set up from the boot descriptor
table, such as EFI Memory Table and e820. Later,
acpi_memory_device_add() calls add_memory() for each ACPI memory device
object as it enumerates ACPI namespace. This add_memory() call is
expected to fail in register_memory_resource() at boot since
iomem_resource has been set up from EFI/e820. As a result, add_memory()
returns -EEXIST, which acpi_memory_device_add() handles as the normal
case.
This scheme works fine, but the following error message is logged for
every ACPI memory device object during boot-up.
"System RAM resource %pR cannot be added\n"
This patch changes register_memory_resource() to use pr_debug() for the
message as it shows up under the normal case.
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After a successful page migration by soft offlining, the source page is
not properly freed and it's never reusable even if we unpoison it
afterward.
This is caused by the race between freeing page and setting PG_hwpoison.
In successful soft offlining, the source page is put (and the refcount
becomes 0) by putback_lru_page() in unmap_and_move(), where it's linked
to pagevec and actual freeing back to buddy is delayed. So if
PG_hwpoison is set for the page before freeing, the freeing does not
functions as expected (in such case freeing aborts in
free_pages_prepare() check.)
This patch tries to make sure to free the source page before setting
PG_hwpoison on it. To avoid reallocating, the page keeps
MIGRATE_ISOLATE until after setting PG_hwpoison.
This patch also removes obsolete comments about "keeping elevated
refcount" because what they say is not true. Unlike memory_failure(),
soft_offline_page() uses no special page isolation code, and the
soft-offlined pages have no elevated.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
vwrite() checks for overflow. vread() should do the same thing.
Since vwrite() checks the source buffer address, vread() should check
the destination buffer address.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- check the length of the procfs data before copying it into a fixed
size array.
- when __parse_numa_zonelist_order() fails, save the error code for
return.
- 'char*' --> 'char *' coding style fix
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Similar to __pagevec_lru_add, this patch removes the LRU parameter from
__lru_cache_add and lru_cache_add_lru as the caller does not control the
exact LRU the page gets added to. lru_cache_add_lru gets renamed to
lru_cache_add the name is silly without the lru parameter. With the
parameter removed, it is required that the caller indicate if they want
the page added to the active or inactive list by setting or clearing
PageActive respectively.
[akpm@linux-foundation.org: Suggested the patch]
[gang.chen@asianux.com: fix used-unintialized warning]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Lyahkov <alexey.lyashkov@gmail.com>
Cc: Andrew Perepechko <anserper@ya.ru>
Cc: Robin Dong <sanbai@taobao.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Bernd Schubert <bernd.schubert@fastmail.fm>
Cc: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that the LRU to add a page to is decided at LRU-add time, remove the
misleading lru parameter from __pagevec_lru_add. A consequence of this
is that the pagevec_lru_add_file, pagevec_lru_add_anon and similar
helpers are misleading as the caller no longer has direct control over
what LRU the page is added to. Unused helpers are removed by this patch
and existing users of pagevec_lru_add_file() are converted to use
lru_cache_add_file() directly and use the per-cpu pagevecs instead of
creating their own pagevec.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Lyahkov <alexey.lyashkov@gmail.com>
Cc: Andrew Perepechko <anserper@ya.ru>
Cc: Robin Dong <sanbai@taobao.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Bernd Schubert <bernd.schubert@fastmail.fm>
Cc: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a page is on a pagevec then it is !PageLRU and mark_page_accessed()
may fail to move a page to the active list as expected. Now that the
LRU is selected at LRU drain time, mark pages PageActive if they are on
the local pagevec so it gets moved to the correct list at LRU drain
time. Using a debugging patch it was found that for a simple git
checkout based workload that pages were never added to the active file
list in practice but with this patch applied they are.
before after
LRU Add Active File 0 750583
LRU Add Active Anon 2640587 2702818
LRU Add Inactive File 8833662 8068353
LRU Add Inactive Anon 207 200
Note that only pages on the local pagevec are considered on purpose. A
!PageLRU page could be in the process of being released, reclaimed,
migrated or on a remote pagevec that is currently being drained.
Marking it PageActive is vunerable to races where PageLRU and Active
bits are checked at the wrong time. Page reclaim will trigger
VM_BUG_ONs but depending on when the race hits, it could also free a
PageActive page to the page allocator and trigger a bad_page warning.
Similarly a potential race exists between a per-cpu drain on a pagevec
list and an activation on a remote CPU.
lru_add_drain_cpu
__pagevec_lru_add
lru = page_lru(page);
mark_page_accessed
if (PageLRU(page))
activate_page
else
SetPageActive
SetPageLRU(page);
add_page_to_lru_list(page, lruvec, lru);
In this case a PageActive page is added to the inactivate list and later
the inactive/active stats will get skewed. While the PageActive checks
in vmscan could be removed and potentially dealt with, a skew in the
statistics would be very difficult to detect. Hence this patch deals
just with the common case where a page being marked accessed has just
been added to the local pagevec.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Jan Kara <jack@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Lyahkov <alexey.lyashkov@gmail.com>
Cc: Andrew Perepechko <anserper@ya.ru>
Cc: Robin Dong <sanbai@taobao.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Bernd Schubert <bernd.schubert@fastmail.fm>
Cc: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mark_page_accessed() cannot activate an inactive page that is located on
an inactive LRU pagevec. Hints from filesystems may be ignored as a
result. In preparation for fixing that problem, this patch removes the
per-LRU pagevecs and leaves just one pagevec. The final LRU the page is
added to is deferred until the pagevec is drained.
This means that fewer pagevecs are available and potentially there is
greater contention on the LRU lock. However, this only applies in the
case where there is an almost perfect mix of file, anon, active and
inactive pages being added to the LRU. In practice I expect that we are
adding stream of pages of a particular time and that the changes in
contention will barely be measurable.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Lyahkov <alexey.lyashkov@gmail.com>
Cc: Andrew Perepechko <anserper@ya.ru>
Cc: Robin Dong <sanbai@taobao.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Bernd Schubert <bernd.schubert@fastmail.fm>
Cc: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrew Perepechko reported a problem whereby pages are being prematurely
evicted as the mark_page_accessed() hint is ignored for pages that are
currently on a pagevec --
http://www.spinics.net/lists/linux-ext4/msg37340.html .
Alexey Lyahkov and Robin Dong have also reported problems recently that
could be due to hot pages reaching the end of the inactive list too
quickly and be reclaimed.
Rather than addressing this on a per-filesystem basis, this series aims
to fix the mark_page_accessed() interface by deferring what LRU a page
is added to pagevec drain time and allowing mark_page_accessed() to call
SetPageActive on a pagevec page.
Patch 1 adds two tracepoints for LRU page activation and insertion. Using
these processes it's possible to build a model of pages in the
LRU that can be processed offline.
Patch 2 defers making the decision on what LRU to add a page to until when
the pagevec is drained.
Patch 3 searches the local pagevec for pages to mark PageActive on
mark_page_accessed. The changelog explains why only the local
pagevec is examined.
Patches 4 and 5 tidy up the API.
postmark, a dd-based test and fs-mark both single and threaded mode were
run but none of them showed any performance degradation or gain as a
result of the patch.
Using patch 1, I built a *very* basic model of the LRU to examine
offline what the average age of different page types on the LRU were in
milliseconds. Of course, capturing the trace distorts the test as it's
written to local disk but it does not matter for the purposes of this
test. The average age of pages in milliseconds were
vanilla deferdrain
Average age mapped anon: 1454 1250
Average age mapped file: 127841 155552
Average age unmapped anon: 85 235
Average age unmapped file: 73633 38884
Average age unmapped buffers: 74054 116155
The LRU activity was mostly files which you'd expect for a dd-based
workload. Note that the average age of buffer pages is increased by the
series and it is expected this is due to the fact that the buffer pages
are now getting added to the active list when drained from the pagevecs.
Note that the average age of the unmapped file data is decreased as they
are still added to the inactive list and are reclaimed before the
buffers.
There is no guarantee this is a universal win for all workloads and it
would be nice if the filesystem people gave some thought as to whether
this decision is generally a win or a loss.
This patch:
Using these tracepoints it is possible to model LRU activity and the
average residency of pages of different types. This can be used to
debug problems related to premature reclaim of pages of particular
types.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Lyahkov <alexey.lyashkov@gmail.com>
Cc: Andrew Perepechko <anserper@ya.ru>
Cc: Robin Dong <sanbai@taobao.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Bernd Schubert <bernd.schubert@fastmail.fm>
Cc: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We want to allocate ELF note segment buffer on the 2nd kernel in vmalloc
space and remap it to user-space in order to reduce the risk that memory
allocation fails on system with huge number of CPUs and so with huge ELF
note segment that exceeds 11-order block size.
Although there's already remap_vmalloc_range for the purpose of
remapping vmalloc memory to user-space, we need to specify user-space
range via vma.
Mmap on /proc/vmcore needs to remap range across multiple objects, so
the interface that requires vma to cover full range is problematic.
This patch introduces remap_vmalloc_range_partial that receives user-space
range as a pair of base address and size and can be used for mmap on
/proc/vmcore case.
remap_vmalloc_range is rewritten using remap_vmalloc_range_partial.
[akpm@linux-foundation.org: use PAGE_ALIGNED()]
Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Lisa Mitchell <lisa.mitchell@hp.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, __find_vmap_area searches for the kernel VM area starting at
a given address. This patch changes this behavior so that it searches
for the kernel VM area to which the address belongs. This change is
needed by remap_vmalloc_range_partial to be introduced in later patch
that receives any position of kernel VM area as target address.
This patch changes the condition (addr > va->va_start) to the equivalent
(addr >= va->va_end) by taking advantage of the fact that each kernel VM
area is non-overlapping.
Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Lisa Mitchell <lisa.mitchell@hp.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mmzone.h documents node_size_lock (which pgdat_resize_lock() locks) as
follows:
* Must be held any time you expect node_start_pfn, node_present_pages
* or node_spanned_pages stay constant. [...]
So actually hold it when we update node_present_pages in __offline_pages().
[akpm@linux-foundation.org: fix build]
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mmzone.h documents node_size_lock (which pgdat_resize_lock() locks) as
follows:
* Must be held any time you expect node_start_pfn, node_present_pages
* or node_spanned_pages stay constant. [...]
So actually hold it when we update node_present_pages in online_pages().
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Page reclaim keeps track of dirty and under writeback pages and uses it
to determine if wait_iff_congested() should stall or if kswapd should
begin writing back pages. This fails to account for buffer pages that
can be under writeback but not PageWriteback which is the case for
filesystems like ext3 ordered mode. Furthermore, PageDirty buffer pages
can have all the buffers clean and writepage does no IO so it should not
be accounted as congested.
This patch adds an address_space operation that filesystems may
optionally use to check if a page is really dirty or really under
writeback. An implementation is provided for for buffer_heads is added
and used for block operations and ext3 in ordered mode. By default the
page flags are obeyed.
Credit goes to Jan Kara for identifying that the page flags alone are
not sufficient for ext3 and sanity checking a number of ideas on how the
problem could be addressed.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently a zone will only be marked congested if the underlying BDI is
congested but if dirty pages are spread across zones it is possible that
an individual zone is full of dirty pages without being congested. The
impact is that zone gets scanned very quickly potentially reclaiming
really clean pages. This patch treats pages marked for immediate
reclaim as congested for the purposes of marking a zone ZONE_CONGESTED
and stalling in wait_iff_congested.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
shrink_inactive_list makes decisions on whether to stall based on the
number of dirty pages encountered. The wait_iff_congested() call in
shrink_page_list does no such thing and it's arbitrary.
This patch moves the decision on whether to set ZONE_CONGESTED and the
wait_iff_congested call into shrink_page_list. This keeps all the
decisions on whether to stall or not in the one place.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In shrink_page_list a decision may be made to stall and flag a zone as
ZONE_WRITEBACK so that if a large number of unqueued dirty pages are
encountered later then the reclaimer will stall. Set ZONE_WRITEBACK
before potentially going to sleep so it is noticed sooner.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit "mm: vmscan: Block kswapd if it is encountering pages under
writeback" blocks page reclaim if it encounters pages under writeback
marked for immediate reclaim. It blocks while pages are still isolated
from the LRU which is unnecessary. This patch defers the blocking until
after the isolated pages have been processed and tidies up some of the
comments.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Further testing of the "Reduce system disruption due to kswapd"
discovered a few problems. First and foremost, it's possible for pages
under writeback to be freed which will lead to badness. Second, as
pages were not being swapped the file LRU was being scanned faster and
clean file pages were being reclaimed. In some cases this results in
increased read IO to re-read data from disk. Third, more pages were
being written from kswapd context which can adversly affect IO
performance. Lastly, it was observed that PageDirty pages are not
necessarily dirty on all filesystems (buffers can be clean while
PageDirty is set and ->writepage generates no IO) and not all
filesystems set PageWriteback when the page is being written (e.g.
ext3). This disconnect confuses the reclaim stalling logic. This
follow-up series is aimed at these problems.
The tests were based on three kernels
vanilla: kernel 3.9 as that is what the current mmotm uses as a baseline
mmotm-20130522 is mmotm as of 22nd May with "Reduce system disruption due to
kswapd" applied on top as per what should be in Andrew's tree
right now
lessdisrupt-v7r10 is this follow-up series on top of the mmotm kernel
The first test used memcached+memcachetest while some background IO was
in progress as implemented by the parallel IO tests implement in MM
Tests. memcachetest benchmarks how many operations/second memcached can
service. It starts with no background IO on a freshly created ext4
filesystem and then re-runs the test with larger amounts of IO in the
background to roughly simulate a large copy in progress. The
expectation is that the IO should have little or no impact on
memcachetest which is running entirely in memory.
parallelio
3.9.0 3.9.0 3.9.0
vanilla mm1-mmotm-20130522 mm1-lessdisrupt-v7r10
Ops memcachetest-0M 23117.00 ( 0.00%) 22780.00 ( -1.46%) 22763.00 ( -1.53%)
Ops memcachetest-715M 23774.00 ( 0.00%) 23299.00 ( -2.00%) 22934.00 ( -3.53%)
Ops memcachetest-2385M 4208.00 ( 0.00%) 24154.00 (474.00%) 23765.00 (464.76%)
Ops memcachetest-4055M 4104.00 ( 0.00%) 25130.00 (512.33%) 24614.00 (499.76%)
Ops io-duration-0M 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops io-duration-715M 12.00 ( 0.00%) 7.00 ( 41.67%) 6.00 ( 50.00%)
Ops io-duration-2385M 116.00 ( 0.00%) 21.00 ( 81.90%) 21.00 ( 81.90%)
Ops io-duration-4055M 160.00 ( 0.00%) 36.00 ( 77.50%) 35.00 ( 78.12%)
Ops swaptotal-0M 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swaptotal-715M 140138.00 ( 0.00%) 18.00 ( 99.99%) 18.00 ( 99.99%)
Ops swaptotal-2385M 385682.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swaptotal-4055M 418029.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-0M 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-715M 144.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-2385M 134227.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-4055M 125618.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops minorfaults-0M 1536429.00 ( 0.00%) 1531632.00 ( 0.31%) 1533541.00 ( 0.19%)
Ops minorfaults-715M 1786996.00 ( 0.00%) 1612148.00 ( 9.78%) 1608832.00 ( 9.97%)
Ops minorfaults-2385M 1757952.00 ( 0.00%) 1614874.00 ( 8.14%) 1613541.00 ( 8.21%)
Ops minorfaults-4055M 1774460.00 ( 0.00%) 1633400.00 ( 7.95%) 1630881.00 ( 8.09%)
Ops majorfaults-0M 1.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops majorfaults-715M 184.00 ( 0.00%) 167.00 ( 9.24%) 166.00 ( 9.78%)
Ops majorfaults-2385M 24444.00 ( 0.00%) 155.00 ( 99.37%) 93.00 ( 99.62%)
Ops majorfaults-4055M 21357.00 ( 0.00%) 147.00 ( 99.31%) 134.00 ( 99.37%)
memcachetest is the transactions/second reported by memcachetest. In
the vanilla kernel note that performance drops from around
23K/sec to just over 4K/second when there is 2385M of IO going
on in the background. With current mmotm, there is no collapse
in performance and with this follow-up series there is little
change.
swaptotal is the total amount of swap traffic. With mmotm and the follow-up
series, the total amount of swapping is much reduced.
3.9.0 3.9.0 3.9.0
vanillamm1-mmotm-20130522mm1-lessdisrupt-v7r10
Minor Faults 11160152 10706748 10622316
Major Faults 46305 755 678
Swap Ins 260249 0 0
Swap Outs 683860 18 18
Direct pages scanned 0 678 2520
Kswapd pages scanned 6046108 8814900 1639279
Kswapd pages reclaimed 1081954 1172267 1094635
Direct pages reclaimed 0 566 2304
Kswapd efficiency 17% 13% 66%
Kswapd velocity 5217.560 7618.953 1414.879
Direct efficiency 100% 83% 91%
Direct velocity 0.000 0.586 2.175
Percentage direct scans 0% 0% 0%
Zone normal velocity 5105.086 6824.681 671.158
Zone dma32 velocity 112.473 794.858 745.896
Zone dma velocity 0.000 0.000 0.000
Page writes by reclaim 1929612.000 6861768.000 32821.000
Page writes file 1245752 6861750 32803
Page writes anon 683860 18 18
Page reclaim immediate 7484 40 239
Sector Reads 1130320 93996 86900
Sector Writes 13508052 10823500 11804436
Page rescued immediate 0 0 0
Slabs scanned 33536 27136 18560
Direct inode steals 0 0 0
Kswapd inode steals 8641 1035 0
Kswapd skipped wait 0 0 0
THP fault alloc 8 37 33
THP collapse alloc 508 552 515
THP splits 24 1 1
THP fault fallback 0 0 0
THP collapse fail 0 0 0
There are a number of observations to make here
1. Swap outs are almost eliminated. Swap ins are 0 indicating that the
pages swapped were really unused anonymous pages. Related to that,
major faults are much reduced.
2. kswapd efficiency was impacted by the initial series but with these
follow-up patches, the efficiency is now at 66% indicating that far
fewer pages were skipped during scanning due to dirty or writeback
pages.
3. kswapd velocity is reduced indicating that fewer pages are being scanned
with the follow-up series as kswapd now stalls when the tail of the
LRU queue is full of unqueued dirty pages. The stall gives flushers a
chance to catch-up so kswapd can reclaim clean pages when it wakes
4. In light of Zlatko's recent reports about zone scanning imbalances,
mmtests now reports scanning velocity on a per-zone basis. With mainline,
you can see that the scanning activity is dominated by the Normal
zone with over 45 times more scanning in Normal than the DMA32 zone.
With the series currently in mmotm, the ratio is slightly better but it
is still the case that the bulk of scanning is in the highest zone. With
this follow-up series, the ratio of scanning between the Normal and
DMA32 zone is roughly equal.
5. As Dave Chinner observed, the current patches in mmotm increased the
number of pages written from kswapd context which is expected to adversly
impact IO performance. With the follow-up patches, far fewer pages are
written from kswapd context than the mainline kernel
6. With the series in mmotm, fewer inodes were reclaimed by kswapd. With
the follow-up series, there is less slab shrinking activity and no inodes
were reclaimed.
7. Note that "Sectors Read" is drastically reduced implying that the source
data being used for the IO is not being aggressively discarded due to
page reclaim skipping over dirty pages and reclaiming clean pages. Note
that the reducion in reads could also be due to inode data not being
re-read from disk after a slab shrink.
3.9.0 3.9.0 3.9.0
vanillamm1-mmotm-20130522mm1-lessdisrupt-v7r10
Mean sda-avgqz 166.99 32.09 33.44
Mean sda-await 853.64 192.76 185.43
Mean sda-r_await 6.31 9.24 5.97
Mean sda-w_await 2992.81 202.65 192.43
Max sda-avgqz 1409.91 718.75 698.98
Max sda-await 6665.74 3538.00 3124.23
Max sda-r_await 58.96 111.95 58.00
Max sda-w_await 28458.94 3977.29 3148.61
In light of the changes in writes from reclaim context, the number of
reads and Dave Chinner's concerns about IO performance I took a closer
look at the IO stats for the test disk. Few observations
1. The average queue size is reduced by the initial series and roughly
the same with this follow up.
2. Average wait times for writes are reduced and as the IO
is completing faster it at least implies that the gain is because
flushers are writing the files efficiently instead of page reclaim
getting in the way.
3. The reduction in maximum write latency is staggering. 28 seconds down
to 3 seconds.
Jan Kara asked how NFS is affected by all of this. Unstable pages can
be taken into account as one of the patches in the series shows but it
is still the case that filesystems with unusual handling of dirty or
writeback could still be treated better.
Tests like postmark, fsmark and largedd showed up nothing useful. On my test
setup, pages are simply not being written back from reclaim context with or
without the patches and there are no changes in performance. My test setup
probably is just not strong enough network-wise to be really interesting.
I ran a longer-lived memcached test with IO going to NFS instead of a local disk
parallelio
3.9.0 3.9.0 3.9.0
vanilla mm1-mmotm-20130522 mm1-lessdisrupt-v7r10
Ops memcachetest-0M 23323.00 ( 0.00%) 23241.00 ( -0.35%) 23321.00 ( -0.01%)
Ops memcachetest-715M 25526.00 ( 0.00%) 24763.00 ( -2.99%) 23242.00 ( -8.95%)
Ops memcachetest-2385M 8814.00 ( 0.00%) 26924.00 (205.47%) 23521.00 (166.86%)
Ops memcachetest-4055M 5835.00 ( 0.00%) 26827.00 (359.76%) 25560.00 (338.05%)
Ops io-duration-0M 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops io-duration-715M 65.00 ( 0.00%) 71.00 ( -9.23%) 11.00 ( 83.08%)
Ops io-duration-2385M 129.00 ( 0.00%) 94.00 ( 27.13%) 53.00 ( 58.91%)
Ops io-duration-4055M 301.00 ( 0.00%) 100.00 ( 66.78%) 108.00 ( 64.12%)
Ops swaptotal-0M 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swaptotal-715M 14394.00 ( 0.00%) 949.00 ( 93.41%) 63.00 ( 99.56%)
Ops swaptotal-2385M 401483.00 ( 0.00%) 24437.00 ( 93.91%) 30118.00 ( 92.50%)
Ops swaptotal-4055M 554123.00 ( 0.00%) 35688.00 ( 93.56%) 63082.00 ( 88.62%)
Ops swapin-0M 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-715M 4522.00 ( 0.00%) 560.00 ( 87.62%) 63.00 ( 98.61%)
Ops swapin-2385M 169861.00 ( 0.00%) 5026.00 ( 97.04%) 13917.00 ( 91.81%)
Ops swapin-4055M 192374.00 ( 0.00%) 10056.00 ( 94.77%) 25729.00 ( 86.63%)
Ops minorfaults-0M 1445969.00 ( 0.00%) 1520878.00 ( -5.18%) 1454024.00 ( -0.56%)
Ops minorfaults-715M 1557288.00 ( 0.00%) 1528482.00 ( 1.85%) 1535776.00 ( 1.38%)
Ops minorfaults-2385M 1692896.00 ( 0.00%) 1570523.00 ( 7.23%) 1559622.00 ( 7.87%)
Ops minorfaults-4055M 1654985.00 ( 0.00%) 1581456.00 ( 4.44%) 1596713.00 ( 3.52%)
Ops majorfaults-0M 0.00 ( 0.00%) 1.00 (-99.00%) 0.00 ( 0.00%)
Ops majorfaults-715M 763.00 ( 0.00%) 265.00 ( 65.27%) 75.00 ( 90.17%)
Ops majorfaults-2385M 23861.00 ( 0.00%) 894.00 ( 96.25%) 2189.00 ( 90.83%)
Ops majorfaults-4055M 27210.00 ( 0.00%) 1569.00 ( 94.23%) 4088.00 ( 84.98%)
1. Performance does not collapse due to IO which is good. IO is also completing
faster. Note with mmotm, IO completes in a third of the time and faster again
with this series applied
2. Swapping is reduced, although not eliminated. The figures for the follow-up
look bad but it does vary a bit as the stalling is not perfect for nfs
or filesystems like ext3 with unusual handling of dirty and writeback
pages
3. There are swapins, particularly with larger amounts of IO indicating
that active pages are being reclaimed. However, the number of much
reduced.
3.9.0 3.9.0 3.9.0
vanillamm1-mmotm-20130522mm1-lessdisrupt-v7r10
Minor Faults 36339175 35025445 35219699
Major Faults 310964 27108 51887
Swap Ins 2176399 173069 333316
Swap Outs 3344050 357228 504824
Direct pages scanned 8972 77283 43242
Kswapd pages scanned 20899983 8939566 14772851
Kswapd pages reclaimed 6193156 5172605 5231026
Direct pages reclaimed 8450 73802 39514
Kswapd efficiency 29% 57% 35%
Kswapd velocity 3929.743 1847.499 3058.840
Direct efficiency 94% 95% 91%
Direct velocity 1.687 15.972 8.954
Percentage direct scans 0% 0% 0%
Zone normal velocity 3721.907 939.103 2185.142
Zone dma32 velocity 209.522 924.368 882.651
Zone dma velocity 0.000 0.000 0.000
Page writes by reclaim 4082185.000 526319.000 537114.000
Page writes file 738135 169091 32290
Page writes anon 3344050 357228 504824
Page reclaim immediate 9524 170 5595843
Sector Reads 8909900 861192 1483680
Sector Writes 13428980 1488744 2076800
Page rescued immediate 0 0 0
Slabs scanned 38016 31744 28672
Direct inode steals 0 0 0
Kswapd inode steals 424 0 0
Kswapd skipped wait 0 0 0
THP fault alloc 14 15 119
THP collapse alloc 1767 1569 1618
THP splits 30 29 25
THP fault fallback 0 0 0
THP collapse fail 8 5 0
Compaction stalls 17 41 100
Compaction success 7 31 95
Compaction failures 10 10 5
Page migrate success 7083 22157 62217
Page migrate failure 0 0 0
Compaction pages isolated 14847 48758 135830
Compaction migrate scanned 18328 48398 138929
Compaction free scanned 2000255 355827 1720269
Compaction cost 7 24 68
I guess the main takeaway again is the much reduced page writes
from reclaim context and reduced reads.
3.9.0 3.9.0 3.9.0
vanillamm1-mmotm-20130522mm1-lessdisrupt-v7r10
Mean sda-avgqz 23.58 0.35 0.44
Mean sda-await 133.47 15.72 15.46
Mean sda-r_await 4.72 4.69 3.95
Mean sda-w_await 507.69 28.40 33.68
Max sda-avgqz 680.60 12.25 23.14
Max sda-await 3958.89 221.83 286.22
Max sda-r_await 63.86 61.23 67.29
Max sda-w_await 11710.38 883.57 1767.28
And as before, write wait times are much reduced.
This patch:
The patch "mm: vmscan: Have kswapd writeback pages based on dirty pages
encountered, not priority" decides whether to writeback pages from reclaim
context based on the number of dirty pages encountered. This situation is
flagged too easily and flushers are not given the chance to catch up
resulting in more pages being written from reclaim context and potentially
impacting IO performance. The check for PageWriteback is also misplaced
as it happens within a PageDirty check which is nonsense as the dirty may
have been cleared for IO. The accounting is updated very late and pages
that are already under writeback, were reactivated, could not unmapped or
could not be released are all missed. Similarly, a page is considered
congested for reasons other than being congested and pages that cannot be
written out in the correct context are skipped. Finally, it considers
stalling and writing back filesystem pages due to encountering dirty
anonymous pages at the tail of the LRU which is dumb.
This patch causes kswapd to begin writing filesystem pages from reclaim
context only if page reclaim found that all filesystem pages at the tail
of the LRU were unqueued dirty pages. Before it starts writing filesystem
pages, it will stall to give flushers a chance to catch up. The decision
on whether wait_iff_congested is also now determined by dirty filesystem
pages only. Congested pages are based on whether the underlying BDI is
congested regardless of the context of the reclaiming process.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
balance_pgdat() is very long and some of the logic can and should be
internal to kswapd_shrink_zone(). Move it so the flow of
balance_pgdat() is marginally easier to follow.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently kswapd checks if it should start writepage as it shrinks each
zone without taking into consideration if the zone is balanced or not.
This is not wrong as such but it does not make much sense either. This
patch checks once per pgdat scan if kswapd should be writing pages.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Historically, kswapd used to congestion_wait() at higher priorities if
it was not making forward progress. This made no sense as the failure
to make progress could be completely independent of IO. It was later
replaced by wait_iff_congested() and removed entirely by commit 258401a6
(mm: don't wait on congested zones in balance_pgdat()) as it was
duplicating logic in shrink_inactive_list().
This is problematic. If kswapd encounters many pages under writeback
and it continues to scan until it reaches the high watermark then it
will quickly skip over the pages under writeback and reclaim clean young
pages or push applications out to swap.
The use of wait_iff_congested() is not suited to kswapd as it will only
stall if the underlying BDI is really congested or a direct reclaimer
was unable to write to the underlying BDI. kswapd bypasses the BDI
congestion as it sets PF_SWAPWRITE but even if this was taken into
account then it would cause direct reclaimers to stall on writeback
which is not desirable.
This patch sets a ZONE_WRITEBACK flag if direct reclaim or kswapd is
encountering too many pages under writeback. If this flag is set and
kswapd encounters a PageReclaim page under writeback then it'll assume
that the LRU lists are being recycled too quickly before IO can complete
and block waiting for some IO to complete.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently kswapd queues dirty pages for writeback if scanning at an
elevated priority but the priority kswapd scans at is not related to the
number of unqueued dirty encountered. Since commit "mm: vmscan: Flatten
kswapd priority loop", the priority is related to the size of the LRU
and the zone watermark which is no indication as to whether kswapd
should write pages or not.
This patch tracks if an excessive number of unqueued dirty pages are
being encountered at the end of the LRU. If so, it indicates that dirty
pages are being recycled before flusher threads can clean them and flags
the zone so that kswapd will start writing pages until the zone is
balanced.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Page reclaim at priority 0 will scan the entire LRU as priority 0 is
considered to be a near OOM condition. Kswapd can reach priority 0
quite easily if it is encountering a large number of pages it cannot
reclaim such as pages under writeback. When this happens, kswapd
reclaims very aggressively even though there may be no real risk of
allocation failure or OOM.
This patch prevents kswapd reaching priority 0 and trying to reclaim the
world. Direct reclaimers will still reach priority 0 in the event of an
OOM situation.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In the past, kswapd makes a decision on whether to compact memory after
the pgdat was considered balanced. This more or less worked but it is
late to make such a decision and does not fit well now that kswapd makes
a decision whether to exit the zone scanning loop depending on reclaim
progress.
This patch will compact a pgdat if at least the requested number of
pages were reclaimed from unbalanced zones for a given priority. If any
zone is currently balanced, kswapd will not call compaction as it is
expected the necessary pages are already available.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kswapd stops raising the scanning priority when at least
SWAP_CLUSTER_MAX pages have been reclaimed or the pgdat is considered
balanced. It then rechecks if it needs to restart at DEF_PRIORITY and
whether high-order reclaim needs to be reset. This is not wrong per-se
but it is confusing to follow and forcing kswapd to stay at DEF_PRIORITY
may require several restarts before it has scanned enough pages to meet
the high watermark even at 100% efficiency. This patch irons out the
logic a bit by controlling when priority is raised and removing the
"goto loop_again".
This patch has kswapd raise the scanning priority until it is scanning
enough pages that it could meet the high watermark in one shrink of the
LRU lists if it is able to reclaim at 100% efficiency. It will not
raise the scanning prioirty higher unless it is failing to reclaim any
pages.
To avoid infinite looping for high-order allocation requests kswapd will
not reclaim for high-order allocations when it has reclaimed at least
twice the number of pages as the allocation request.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Simplistically, the anon and file LRU lists are scanned proportionally
depending on the value of vm.swappiness although there are other factors
taken into account by get_scan_count(). The patch "mm: vmscan: Limit
the number of pages kswapd reclaims" limits the number of pages kswapd
reclaims but it breaks this proportional scanning and may evenly shrink
anon/file LRUs regardless of vm.swappiness.
This patch preserves the proportional scanning and reclaim. It does
mean that kswapd will reclaim more than requested but the number of
pages will be related to the high watermark.
[mhocko@suse.cz: Correct proportional reclaim for memcg and simplify]
[kamezawa.hiroyu@jp.fujitsu.com: Recalculate scan based on target]
[hannes@cmpxchg.org: Account for already scanned pages properly]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This series does not fix all the current known problems with reclaim but
it addresses one important swapping bug when there is background IO.
Changelog since V3
- Drop the slab shrink changes in light of Glaubers series and
discussions highlighted that there were a number of potential
problems with the patch. (mel)
- Rebased to 3.10-rc1
Changelog since V2
- Preserve ratio properly for proportional scanning (kamezawa)
Changelog since V1
- Rename ZONE_DIRTY to ZONE_TAIL_LRU_DIRTY (andi)
- Reformat comment in shrink_page_list (andi)
- Clarify some comments (dhillf)
- Rework how the proportional scanning is preserved
- Add PageReclaim check before kswapd starts writeback
- Reset sc.nr_reclaimed on every full zone scan
Kswapd and page reclaim behaviour has been screwy in one way or the
other for a long time. Very broadly speaking it worked in the far past
because machines were limited in memory so it did not have that many
pages to scan and it stalled congestion_wait() frequently to prevent it
going completely nuts. In recent times it has behaved very
unsatisfactorily with some of the problems compounded by the removal of
stall logic and the introduction of transparent hugepage support with
high-order reclaims.
There are many variations of bugs that are rooted in this area. One
example is reports of a large copy operations or backup causing the
machine to grind to a halt or applications pushed to swap. Sometimes in
low memory situations a large percentage of memory suddenly gets
reclaimed. In other cases an application starts and kswapd hits 100%
CPU usage for prolonged periods of time and so on. There is now talk of
introducing features like an extra free kbytes tunable to work around
aspects of the problem instead of trying to deal with it. It's
compounded by the problem that it can be very workload and machine
specific.
This series aims at addressing some of the worst of these problems
without attempting to fundmentally alter how page reclaim works.
Patches 1-2 limits the number of pages kswapd reclaims while still obeying
the anon/file proportion of the LRUs it should be scanning.
Patches 3-4 control how and when kswapd raises its scanning priority and
deletes the scanning restart logic which is tricky to follow.
Patch 5 notes that it is too easy for kswapd to reach priority 0 when
scanning and then reclaim the world. Down with that sort of thing.
Patch 6 notes that kswapd starts writeback based on scanning priority which
is not necessarily related to dirty pages. It will have kswapd
writeback pages if a number of unqueued dirty pages have been
recently encountered at the tail of the LRU.
Patch 7 notes that sometimes kswapd should stall waiting on IO to complete
to reduce LRU churn and the likelihood that it'll reclaim young
clean pages or push applications to swap. It will cause kswapd
to block on IO if it detects that pages being reclaimed under
writeback are recycling through the LRU before the IO completes.
Patchies 8-9 are cosmetic but balance_pgdat() is easier to follow after they
are applied.
This was tested using memcached+memcachetest while some background IO
was in progress as implemented by the parallel IO tests implement in MM
Tests.
memcachetest benchmarks how many operations/second memcached can service
and it is run multiple times. It starts with no background IO and then
re-runs the test with larger amounts of IO in the background to roughly
simulate a large copy in progress. The expectation is that the IO
should have little or no impact on memcachetest which is running
entirely in memory.
3.10.0-rc1 3.10.0-rc1
vanilla lessdisrupt-v4
Ops memcachetest-0M 22155.00 ( 0.00%) 22180.00 ( 0.11%)
Ops memcachetest-715M 22720.00 ( 0.00%) 22355.00 ( -1.61%)
Ops memcachetest-2385M 3939.00 ( 0.00%) 23450.00 (495.33%)
Ops memcachetest-4055M 3628.00 ( 0.00%) 24341.00 (570.92%)
Ops io-duration-0M 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops io-duration-715M 12.00 ( 0.00%) 7.00 ( 41.67%)
Ops io-duration-2385M 118.00 ( 0.00%) 21.00 ( 82.20%)
Ops io-duration-4055M 162.00 ( 0.00%) 36.00 ( 77.78%)
Ops swaptotal-0M 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swaptotal-715M 140134.00 ( 0.00%) 18.00 ( 99.99%)
Ops swaptotal-2385M 392438.00 ( 0.00%) 0.00 ( 0.00%)
Ops swaptotal-4055M 449037.00 ( 0.00%) 27864.00 ( 93.79%)
Ops swapin-0M 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-715M 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-2385M 148031.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-4055M 135109.00 ( 0.00%) 0.00 ( 0.00%)
Ops minorfaults-0M 1529984.00 ( 0.00%) 1530235.00 ( -0.02%)
Ops minorfaults-715M 1794168.00 ( 0.00%) 1613750.00 ( 10.06%)
Ops minorfaults-2385M 1739813.00 ( 0.00%) 1609396.00 ( 7.50%)
Ops minorfaults-4055M 1754460.00 ( 0.00%) 1614810.00 ( 7.96%)
Ops majorfaults-0M 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops majorfaults-715M 185.00 ( 0.00%) 180.00 ( 2.70%)
Ops majorfaults-2385M 24472.00 ( 0.00%) 101.00 ( 99.59%)
Ops majorfaults-4055M 22302.00 ( 0.00%) 229.00 ( 98.97%)
Note how the vanilla kernels performance collapses when there is enough
IO taking place in the background. This drop in performance is part of
what users complain of when they start backups. Note how the swapin and
major fault figures indicate that processes were being pushed to swap
prematurely. With the series applied, there is no noticable performance
drop and while there is still some swap activity, it's tiny.
20 iterations of this test were run in total and averaged. Every 5
iterations, additional IO was generated in the background using dd to
measure how the workload was impacted. The 0M, 715M, 2385M and 4055M
subblock refer to the amount of IO going on in the background at each
iteration. So memcachetest-2385M is reporting how many
transactions/second memcachetest recorded on average over 5 iterations
while there was 2385M of IO going on in the ground. There are six
blocks of information reported here
memcachetest is the transactions/second reported by memcachetest. In
the vanilla kernel note that performance drops from around
22K/sec to just under 4K/second when there is 2385M of IO going
on in the background. This is one type of performance collapse
users complain about if a large cp or backup starts in the
background
io-duration refers to how long it takes for the background IO to
complete. It's showing that with the patched kernel that the IO
completes faster while not interfering with the memcache
workload
swaptotal is the total amount of swap traffic. With the patched kernel,
the total amount of swapping is much reduced although it is
still not zero.
swapin in this case is an indication as to whether we are swap trashing.
The closer the swapin/swapout ratio is to 1, the worse the
trashing is. Note with the patched kernel that there is no swapin
activity indicating that all the pages swapped were really inactive
unused pages.
minorfaults are just minor faults. An increased number of minor faults
can indicate that page reclaim is unmapping the pages but not
swapping them out before they are faulted back in. With the
patched kernel, there is only a small change in minor faults
majorfaults are just major faults in the target workload and a high
number can indicate that a workload is being prematurely
swapped. With the patched kernel, major faults are much reduced. As
there are no swapin's recorded so it's not being swapped. The likely
explanation is that that libraries or configuration files used by
the workload during startup get paged out by the background IO.
Overall with the series applied, there is no noticable performance drop
due to background IO and while there is still some swap activity, it's
tiny and the lack of swapins imply that the swapped pages were inactive
and unused.
3.10.0-rc1 3.10.0-rc1
vanilla lessdisrupt-v4
Page Ins 1234608 101892
Page Outs 12446272 11810468
Swap Ins 283406 0
Swap Outs 698469 27882
Direct pages scanned 0 136480
Kswapd pages scanned 6266537 5369364
Kswapd pages reclaimed 1088989 930832
Direct pages reclaimed 0 120901
Kswapd efficiency 17% 17%
Kswapd velocity 5398.371 4635.115
Direct efficiency 100% 88%
Direct velocity 0.000 117.817
Percentage direct scans 0% 2%
Page writes by reclaim 1655843 4009929
Page writes file 957374 3982047
Page writes anon 698469 27882
Page reclaim immediate 5245 1745
Page rescued immediate 0 0
Slabs scanned 33664 25216
Direct inode steals 0 0
Kswapd inode steals 19409 778
Kswapd skipped wait 0 0
THP fault alloc 35 30
THP collapse alloc 472 401
THP splits 27 22
THP fault fallback 0 0
THP collapse fail 0 1
Compaction stalls 0 4
Compaction success 0 0
Compaction failures 0 4
Page migrate success 0 0
Page migrate failure 0 0
Compaction pages isolated 0 0
Compaction migrate scanned 0 0
Compaction free scanned 0 0
Compaction cost 0 0
NUMA PTE updates 0 0
NUMA hint faults 0 0
NUMA hint local faults 0 0
NUMA pages migrated 0 0
AutoNUMA cost 0 0
Unfortunately, note that there is a small amount of direct reclaim due to
kswapd no longer reclaiming the world. ftrace indicates that the direct
reclaim stalls are mostly harmless with the vast bulk of the stalls
incurred by dd
23 tclsh-3367
38 memcachetest-13733
49 memcachetest-12443
57 tee-3368
1541 dd-13826
1981 dd-12539
A consequence of the direct reclaim for dd is that the processes for the
IO workload may show a higher system CPU usage. There is also a risk that
kswapd not reclaiming the world may mean that it stays awake balancing
zones, does not stall on the appropriate events and continually scans
pages it cannot reclaim consuming CPU. This will be visible as continued
high CPU usage but in my own tests I only saw a single spike lasting less
than a second and I did not observe any problems related to reclaim while
running the series on my desktop.
This patch:
The number of pages kswapd can reclaim is bound by the number of pages it
scans which is related to the size of the zone and the scanning priority.
In many cases the priority remains low because it's reset every
SWAP_CLUSTER_MAX reclaimed pages but in the event kswapd scans a large
number of pages it cannot reclaim, it will raise the priority and
potentially discard a large percentage of the zone as sc->nr_to_reclaim is
ULONG_MAX. The user-visible effect is a reclaim "spike" where a large
percentage of memory is suddenly freed. It would be bad enough if this
was just unused memory but because of how anon/file pages are balanced it
is possible that applications get pushed to swap unnecessarily.
This patch limits the number of pages kswapd will reclaim to the high
watermark. Reclaim will still overshoot due to it not being a hard limit
as shrink_lruvec() will ignore the sc.nr_to_reclaim at DEF_PRIORITY but it
prevents kswapd reclaiming the world at higher priorities. The number of
pages it reclaims is not adjusted for high-order allocations as kswapd
will reclaim excessively if it is to balance zones for high-order
allocations.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When memory hotplug is triggered, we call pageset_init() on
per-cpu-pagesets which both contain pages and are in use, causing both the
leakage of those pages and (potentially) bad behaviour if a page is
allocated from a pageset while it is being cleared.
Avoid this by factoring out pageset_set_high_and_batch() (which contains
all needed logic too set a pageset's ->high and ->batch inrespective of
system state) from zone_pageset_init() and using the new
pageset_set_high_and_batch() instead of zone_pageset_init() in
zone_pcp_update().
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Simply moves calculation of the new 'high' value outside the
for_each_possible_cpu() loop, as it does not depend on the cpu.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
zone_pcp_update()'s goal is to adjust the ->high and ->mark members of a
percpu pageset based on a zone's ->managed_pages. We don't need to drain
the entire percpu pageset just to modify these fields.
This lets us avoid calling setup_pageset() (and the draining required to
call it) and instead allows simply setting the fields' values (with some
attention paid to memory barriers to prevent the relationship between
->batch and ->high from being thrown off).
This does change the behavior of zone_pcp_update() as the percpu pagesets
will not be drained when zone_pcp_update() is called (they will end up
being shrunk, not completely drained, later when a 0-order page is freed
in free_hot_cold_page()).
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pcp->batch could change at any point, avoid relying on it being a stable
value.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce pageset_update() to perform a safe transision from one set of
pcp->{batch,high} to a new set using memory barriers.
This ensures that batch is always set to a safe value (1) prior to
updating high, and ensure that high is fully updated before setting the
real value of batch. It avoids ->batch ever rising above ->high.
Suggested by Gilad Ben-Yossef in these threads:
https://lkml.org/lkml/2013/4/9/23https://lkml.org/lkml/2013/4/10/49
Also reproduces his proposed comment.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Reviewed-by: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Because we are going to rely upon a careful transision between old and new
->high and ->batch values using memory barriers and will remove
stop_machine(), we need to prevent multiple updaters from interweaving
their memory writes.
Add a simple mutex to protect both update loops.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
"Problems" with the current code:
1: there is a lack of synchronization in setting ->high and ->batch in
percpu_pagelist_fraction_sysctl_handler()
2: stop_machine() in zone_pcp_update() is unnecissary.
3: zone_pcp_update() does not consider the case where
percpu_pagelist_fraction is non-zero
To fix:
1: add memory barriers, a safe ->batch value, an update side mutex when
updating ->high and ->batch, and use ACCESS_ONCE() for ->batch users
that expect a stable value.
2: avoid draining pages in zone_pcp_update(), rely upon the memory
barriers added to fix#1
3: factor out quite a few functions, and then call the appropriate one.
Note that it results in a change to the behavior of zone_pcp_update(),
which is used by memory_hotplug. I'm rather certain that I've diserned
(and preserved) the essential behavior (changing ->high and ->batch), and
only eliminated unneeded actions (draining the per cpu pages), but this
may not be the case.
Further note that the draining of pages that previously took place in
zone_pcp_update() occured after repeated draining when attempting to
offline a page, and after the offline has "succeeded". It appears that
the draining was added to zone_pcp_update() to avoid refactoring
setup_pageset() into 2 funtions.
This patch:
Creates pageset_set_batch() for use in setup_pageset().
pageset_set_batch() imitates the functionality of
setup_pagelist_highmark(), but uses the boot time
(percpu_pagelist_fraction == 0) calculations for determining ->high based
on ->batch.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(*->vm_end - *->vm_start) >> PAGE_SHIFT operation is implemented
as a inline funcion vma_pages() in linux/mm.h, so using it.
Signed-off-by: Libin <huawei.libin@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Swap subsystem does lazy swap slot free with expecting the page would be
swapped out again so we can avoid unnecessary write.
But the problem in in-memory swap(ex, zram) is that it consumes memory
space until vm_swap_full(ie, used half of all of swap device) condition
meet. It could be bad if we use multiple swap device, small in-memory
swap and big storage swap or in-memory swap alone.
This patch makes swap subsystem free swap slot as soon as swap-read is
completed and make the swapcache page dirty so the page should be
written out the swap device to reclaim it. It means we never lose it.
I tested this patch with kernel compile workload.
1. before
compile time : 9882.42
zram max wasted space by fragmentation: 13471881 byte
memory space consumed by zram: 174227456 byte
the number of slot free notify: 206684
2. after
compile time : 9653.90
zram max wasted space by fragmentation: 11805932 byte
memory space consumed by zram: 154001408 byte
the number of slot free notify: 426972
[akpm@linux-foundation.org: tweak comment text]
[artem.savkov@gmail.com: fix BUG due to non-swapcache pages in end_swap_bio_read()]
[akpm@linux-foundation.org: invert unlikely() test, augment comment, 80-col cleanup]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Artem Savkov <artem.savkov@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Konrad Rzeszutek Wilk <konrad@darnok.org>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For processes that have detached their mm's, task_in_mem_cgroup()
unnecessarily takes task_lock() when rcu_read_lock() is all that is
necessary to call mem_cgroup_from_task().
While we're here, switch task_in_mem_cgroup() to return bool.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The soft-dirty is a bit on a PTE which helps to track which pages a task
writes to. In order to do this tracking one should
1. Clear soft-dirty bits from PTEs ("echo 4 > /proc/PID/clear_refs)
2. Wait some time.
3. Read soft-dirty bits (55'th in /proc/PID/pagemap2 entries)
To do this tracking, the writable bit is cleared from PTEs when the
soft-dirty bit is. Thus, after this, when the task tries to modify a
page at some virtual address the #PF occurs and the kernel sets the
soft-dirty bit on the respective PTE.
Note, that although all the task's address space is marked as r/o after
the soft-dirty bits clear, the #PF-s that occur after that are processed
fast. This is so, since the pages are still mapped to physical memory,
and thus all the kernel does is finds this fact out and puts back
writable, dirty and soft-dirty bits on the PTE.
Another thing to note, is that when mremap moves PTEs they are marked
with soft-dirty as well, since from the user perspective mremap modifies
the virtual memory at mremap's new address.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Hotplug changes allowing device hot-removal operations to fail
gracefully (instead of crashing the kernel) if they cannot be
carried out completely. From Rafael J Wysocki and Toshi Kani.
- Freezer update from Colin Cross and Mandeep Singh Baines targeted
at making the freezing of tasks a bit less heavy weight operation.
- cpufreq resume fix from Srivatsa S Bhat for a regression introduced
during the 3.10 cycle causing some cpufreq sysfs attributes to
return wrong values to user space after resume.
- New freqdomain_cpus sysfs attribute for the acpi-cpufreq driver to
provide information previously available via related_cpus from
Lan Tianyu.
- cpufreq fixes and cleanups from Viresh Kumar, Jacob Shin,
Heiko Stübner, Xiaoguang Chen, Ezequiel Garcia, Arnd Bergmann, and
Tang Yuantian.
- Fix for an ACPICA regression causing suspend/resume issues to
appear on some systems introduced during the 3.4 development cycle
from Lv Zheng.
- ACPICA fixes and cleanups from Bob Moore, Tomasz Nowicki, Lv Zheng,
Chao Guan, and Zhang Rui.
- New cupidle driver for Xilinx Zynq processors from Michal Simek.
- cpuidle fixes and cleanups from Daniel Lezcano.
- Changes to make suspend/resume work correctly in Xen guests from
Konrad Rzeszutek Wilk.
- ACPI device power management fixes and cleanups from Fengguang Wu
and Rafael J Wysocki.
- ACPI documentation updates from Lv Zheng, Aaron Lu and Hanjun Guo.
- Fix for the IA-64 issue that was the reason for reverting commit
9f29ab1 and updates of the ACPI scan code from Rafael J Wysocki.
- Mechanism for adding CMOS RTC address space handlers from Lan Tianyu
(to allow some EC-related breakage to be fixed on some systems).
- Spec-compliant implementation of acpi_os_get_timer() from
Mika Westerberg.
- Modification of do_acpi_find_child() to execute _STA in order to
to avoid situations in which a pointer to a disabled device object
is returned instead of an enabled one with the same _ADR value.
From Jeff Wu.
- Intel BayTrail PCH (Platform Controller Hub) support for the ACPI
Intel Low-Power Subsystems (LPSS) driver and modificaions of that
driver to work around a couple of known BIOS issues from
Mika Westerberg and Heikki Krogerus.
- EC driver fix from Vasiliy Kulikov to make it use get_user() and
put_user() instead of dereferencing user space pointers blindly.
- Assorted ACPI code cleanups from Bjorn Helgaas, Nicholas Mazzuca and
Toshi Kani.
- Modification of the "runtime idle" helper routine to take the return
values of the callbacks executed by it into account and to call
rpm_suspend() if they return 0, which allows some code bloat
reduction to be done, from Rafael J Wysocki and Alan Stern.
- New trace points for PM QoS from Sahara <keun-o.park@windriver.com>.
- PM QoS documentation update from Lan Tianyu.
- Assorted core PM code cleanups and changes from Bernie Thompson,
Bjorn Helgaas, Julius Werner, and Shuah Khan.
- New devfreq driver for the Exynos5-bus device from Abhilash Kesavan.
- Minor devfreq cleanups, fixes and MAINTAINERS update from
MyungJoo Ham, Abhilash Kesavan, Paul Bolle, Rajagopal Venkat, and
Wei Yongjun.
- OMAP Adaptive Voltage Scaling (AVS) SmartReflex voltage control
driver updates from Andrii Tseglytskyi and Nishanth Menon.
/
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Merge tag 'pm+acpi-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management and ACPI updates from Rafael Wysocki:
"This time the total number of ACPI commits is slightly greater than
the number of cpufreq commits, but Viresh Kumar (who works on cpufreq)
remains the most active patch submitter.
To me, the most significant change is the addition of offline/online
device operations to the driver core (with the Greg's blessing) and
the related modifications of the ACPI core hotplug code. Next are the
freezer updates from Colin Cross that should make the freezing of
tasks a bit less heavy weight.
We also have a couple of regression fixes, a number of fixes for
issues that have not been identified as regressions, two new drivers
and a bunch of cleanups all over.
Highlights:
- Hotplug changes to support graceful hot-removal failures.
It sometimes is necessary to fail device hot-removal operations
gracefully if they cannot be carried out completely. For example,
if memory from a memory module being hot-removed has been allocated
for the kernel's own use and cannot be moved elsewhere, it's
desirable to fail the hot-removal operation in a graceful way
rather than to crash the kernel, but currenty a success or a kernel
crash are the only possible outcomes of an attempted memory
hot-removal. Needless to say, that is not a very attractive
alternative and it had to be addressed.
However, in order to make it work for memory, I first had to make
it work for CPUs and for this purpose I needed to modify the ACPI
processor driver. It's been split into two parts, a resident one
handling the low-level initialization/cleanup and a modular one
playing the actual driver's role (but it binds to the CPU system
device objects rather than to the ACPI device objects representing
processors). That's been sort of like a live brain surgery on a
patient who's riding a bike.
So this is a little scary, but since we found and fixed a couple of
regressions it caused to happen during the early linux-next testing
(a month ago), nobody has complained.
As a bonus we remove some duplicated ACPI hotplug code, because the
ACPI-based CPU hotplug is now going to use the common ACPI hotplug
code.
- Lighter weight freezing of tasks.
These changes from Colin Cross and Mandeep Singh Baines are
targeted at making the freezing of tasks a bit less heavy weight
operation. They reduce the number of tasks woken up every time
during the freezing, by using the observation that the freezer
simply doesn't need to wake up some of them and wait for them all
to call refrigerator(). The time needed for the freezer to decide
to report a failure is reduced too.
Also reintroduced is the check causing a lockdep warining to
trigger when try_to_freeze() is called with locks held (which is
generally unsafe and shouldn't happen).
- cpufreq updates
First off, a commit from Srivatsa S Bhat fixes a resume regression
introduced during the 3.10 cycle causing some cpufreq sysfs
attributes to return wrong values to user space after resume. The
fix is kind of fresh, but also it's pretty obvious once Srivatsa
has identified the root cause.
Second, we have a new freqdomain_cpus sysfs attribute for the
acpi-cpufreq driver to provide information previously available via
related_cpus. From Lan Tianyu.
Finally, we fix a number of issues, mostly related to the
CPUFREQ_POSTCHANGE notifier and cpufreq Kconfig options and clean
up some code. The majority of changes from Viresh Kumar with bits
from Jacob Shin, Heiko Stübner, Xiaoguang Chen, Ezequiel Garcia,
Arnd Bergmann, and Tang Yuantian.
- ACPICA update
A usual bunch of updates from the ACPICA upstream.
During the 3.4 cycle we introduced support for ACPI 5 extended
sleep registers, but they are only supposed to be used if the
HW-reduced mode bit is set in the FADT flags and the code attempted
to use them without checking that bit. That caused suspend/resume
regressions to happen on some systems. Fix from Lv Zheng causes
those registers to be used only if the HW-reduced mode bit is set.
Apart from this some other ACPICA bugs are fixed and code cleanups
are made by Bob Moore, Tomasz Nowicki, Lv Zheng, Chao Guan, and
Zhang Rui.
- cpuidle updates
New driver for Xilinx Zynq processors is added by Michal Simek.
Multidriver support simplification, addition of some missing
kerneldoc comments and Kconfig-related fixes come from Daniel
Lezcano.
- ACPI power management updates
Changes to make suspend/resume work correctly in Xen guests from
Konrad Rzeszutek Wilk, sparse warning fix from Fengguang Wu and
cleanups and fixes of the ACPI device power state selection
routine.
- ACPI documentation updates
Some previously missing pieces of ACPI documentation are added by
Lv Zheng and Aaron Lu (hopefully, that will help people to
uderstand how the ACPI subsystem works) and one outdated doc is
updated by Hanjun Guo.
- Assorted ACPI updates
We finally nailed down the IA-64 issue that was the reason for
reverting commit 9f29ab11dd ("ACPI / scan: do not match drivers
against objects having scan handlers"), so we can fix it and move
the ACPI scan handler check added to the ACPI video driver back to
the core.
A mechanism for adding CMOS RTC address space handlers is
introduced by Lan Tianyu to allow some EC-related breakage to be
fixed on some systems.
A spec-compliant implementation of acpi_os_get_timer() is added by
Mika Westerberg.
The evaluation of _STA is added to do_acpi_find_child() to avoid
situations in which a pointer to a disabled device object is
returned instead of an enabled one with the same _ADR value. From
Jeff Wu.
Intel BayTrail PCH (Platform Controller Hub) support is added to
the ACPI driver for Intel Low-Power Subsystems (LPSS) and that
driver is modified to work around a couple of known BIOS issues.
Changes from Mika Westerberg and Heikki Krogerus.
The EC driver is fixed by Vasiliy Kulikov to use get_user() and
put_user() instead of dereferencing user space pointers blindly.
Code cleanups are made by Bjorn Helgaas, Nicholas Mazzuca and Toshi
Kani.
- Assorted power management updates
The "runtime idle" helper routine is changed to take the return
values of the callbacks executed by it into account and to call
rpm_suspend() if they return 0, which allows us to reduce the
overall code bloat a bit (by dropping some code that's not
necessary any more after that modification).
The runtime PM documentation is updated by Alan Stern (to reflect
the "runtime idle" behavior change).
New trace points for PM QoS are added by Sahara
(<keun-o.park@windriver.com>).
PM QoS documentation is updated by Lan Tianyu.
Code cleanups are made and minor issues are addressed by Bernie
Thompson, Bjorn Helgaas, Julius Werner, and Shuah Khan.
- devfreq updates
New driver for the Exynos5-bus device from Abhilash Kesavan.
Minor cleanups, fixes and MAINTAINERS update from MyungJoo Ham,
Abhilash Kesavan, Paul Bolle, Rajagopal Venkat, and Wei Yongjun.
- OMAP power management updates
Adaptive Voltage Scaling (AVS) SmartReflex voltage control driver
updates from Andrii Tseglytskyi and Nishanth Menon."
* tag 'pm+acpi-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (162 commits)
cpufreq: Fix cpufreq regression after suspend/resume
ACPI / PM: Fix possible NULL pointer deref in acpi_pm_device_sleep_state()
PM / Sleep: Warn about system time after resume with pm_trace
cpufreq: don't leave stale policy pointer in cdbs->cur_policy
acpi-cpufreq: Add new sysfs attribute freqdomain_cpus
cpufreq: make sure frequency transitions are serialized
ACPI: implement acpi_os_get_timer() according the spec
ACPI / EC: Add HP Folio 13 to ec_dmi_table in order to skip DSDT scan
ACPI: Add CMOS RTC Operation Region handler support
ACPI / processor: Drop unused variable from processor_perflib.c
cpufreq: tegra: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: s3c64xx: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: omap: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: imx6q: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: exynos: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: dbx500: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: davinci: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: arm-big-little: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: powernow-k8: call CPUFREQ_POSTCHANGE notfier in error cases
cpufreq: pcc: call CPUFREQ_POSTCHANGE notfier in error cases
...
Pull security subsystem updates from James Morris:
"In this update, Smack learns to love IPv6 and to mount a filesystem
with a transmutable hierarchy (i.e. security labels are inherited
from parent directory upon creation rather than creating process).
The rest of the changes are maintenance"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (37 commits)
tpm/tpm_i2c_infineon: Remove unused header file
tpm: tpm_i2c_infinion: Don't modify i2c_client->driver
evm: audit integrity metadata failures
integrity: move integrity_audit_msg()
evm: calculate HMAC after initializing posix acl on tmpfs
maintainers: add Dmitry Kasatkin
Smack: Fix the bug smackcipso can't set CIPSO correctly
Smack: Fix possible NULL pointer dereference at smk_netlbl_mls()
Smack: Add smkfstransmute mount option
Smack: Improve access check performance
Smack: Local IPv6 port based controls
tpm: fix regression caused by section type conflict of tpm_dev_release() in ppc builds
maintainers: Remove Kent from maintainers
tpm: move TPM_DIGEST_SIZE defintion
tpm_tis: missing platform_driver_unregister() on error in init_tis()
security: clarify cap_inode_getsecctx description
apparmor: no need to delay vfree()
apparmor: fix fully qualified name parsing
apparmor: fix setprocattr arg processing for onexec
apparmor: localize getting the security context to a few macros
...
- KVM and Xen ports to AArch64
- Hugetlbfs and transparent huge pages support for arm64
- Applied Micro X-Gene Kconfig entry and dts file
- Cache flushing improvements
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64
Pull ARM64 updates from Catalin Marinas:
"Main features:
- KVM and Xen ports to AArch64
- Hugetlbfs and transparent huge pages support for arm64
- Applied Micro X-Gene Kconfig entry and dts file
- Cache flushing improvements
For arm64 huge pages support, there are x86 changes moving part of
arch/x86/mm/hugetlbpage.c into mm/hugetlb.c to be re-used by arm64"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64: (66 commits)
arm64: Add initial DTS for APM X-Gene Storm SOC and APM Mustang board
arm64: Add defines for APM ARMv8 implementation
arm64: Enable APM X-Gene SOC family in the defconfig
arm64: Add Kconfig option for APM X-Gene SOC family
arm64/Makefile: provide vdso_install target
ARM64: mm: THP support.
ARM64: mm: Raise MAX_ORDER for 64KB pages and THP.
ARM64: mm: HugeTLB support.
ARM64: mm: Move PTE_PROT_NONE bit.
ARM64: mm: Make PAGE_NONE pages read only and no-execute.
ARM64: mm: Restore memblock limit when map_mem finished.
mm: thp: Correct the HPAGE_PMD_ORDER check.
x86: mm: Remove general hugetlb code from x86.
mm: hugetlb: Copy general hugetlb code from x86 to mm.
x86: mm: Remove x86 version of huge_pmd_share.
mm: hugetlb: Copy huge_pmd_share from x86 to mm.
arm64: KVM: document kernel object mappings in HYP
arm64: KVM: MAINTAINERS update
arm64: KVM: userspace API documentation
arm64: KVM: enable initialization of a 32bit vcpu
...
Pull second set of VFS changes from Al Viro:
"Assorted f_pos race fixes, making do_splice_direct() safe to call with
i_mutex on parent, O_TMPFILE support, Jeff's locks.c series,
->d_hash/->d_compare calling conventions changes from Linus, misc
stuff all over the place."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
Document ->tmpfile()
ext4: ->tmpfile() support
vfs: export lseek_execute() to modules
lseek_execute() doesn't need an inode passed to it
block_dev: switch to fixed_size_llseek()
cpqphp_sysfs: switch to fixed_size_llseek()
tile-srom: switch to fixed_size_llseek()
proc_powerpc: switch to fixed_size_llseek()
ubi/cdev: switch to fixed_size_llseek()
pci/proc: switch to fixed_size_llseek()
isapnp: switch to fixed_size_llseek()
lpfc: switch to fixed_size_llseek()
locks: give the blocked_hash its own spinlock
locks: add a new "lm_owner_key" lock operation
locks: turn the blocked_list into a hashtable
locks: convert fl_link to a hlist_node
locks: avoid taking global lock if possible when waking up blocked waiters
locks: protect most of the file_lock handling with i_lock
locks: encapsulate the fl_link list handling
locks: make "added" in __posix_lock_file a bool
...
For those file systems(btrfs/ext4/ocfs2/tmpfs) that support
SEEK_DATA/SEEK_HOLE functions, we end up handling the similar
matter in lseek_execute() to update the current file offset
to the desired offset if it is valid, ceph also does the
simliar things at ceph_llseek().
To reduce the duplications, this patch make lseek_execute()
public accessible so that we can call it directly from the
underlying file systems.
Thanks Dave Chinner for this suggestion.
[AV: call it vfs_setpos(), don't bring the removed 'inode' argument back]
v2->v1:
- Add kernel-doc comments for lseek_execute()
- Call lseek_execute() in ceph->llseek()
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: Josef Bacik <jbacik@fusionio.com>
Cc: Ben Myers <bpm@sgi.com>
Cc: Ted Tso <tytso@mit.edu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Sage Weil <sage@inktank.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull voluntary preemption fixes from Ingo Molnar:
"This tree contains a speedup which is achieved through better
might_sleep()/might_fault() preemption point annotations for uaccess
functions, by Michael S Tsirkin:
1. The only reason uaccess routines might sleep is if they fault.
Make this explicit for all architectures.
2. A voluntary preemption point in uaccess functions means compiler
can't inline them efficiently, this breaks assumptions that they
are very fast and small that e.g. net code seems to make. Remove
this preemption point so behaviour matches with what callers
assume.
3. Accesses (e.g through socket ops) to kernel memory with KERNEL_DS
like net/sunrpc does will never sleep. Remove an unconditinal
might_sleep() in the might_fault() inline in kernel.h (used when
PROVE_LOCKING is not set).
4. Accesses with pagefault_disable() return EFAULT but won't cause
caller to sleep. Check for that and thus avoid might_sleep() when
PROVE_LOCKING is set.
These changes offer a nice speedup for CONFIG_PREEMPT_VOLUNTARY=y
kernels, here's a network bandwidth measurement between a virtual
machine and the host:
before:
incoming: 7122.77 Mb/s
outgoing: 8480.37 Mb/s
after:
incoming: 8619.24 Mb/s [ +21.0% ]
outgoing: 9455.42 Mb/s [ +11.5% ]
I kept these changes in a separate tree, separate from scheduler
changes, because it's a mixed MM and scheduler topic"
* 'sched-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
mm, sched: Allow uaccess in atomic with pagefault_disable()
mm, sched: Drop voluntary schedule from might_fault()
x86: uaccess s/might_sleep/might_fault/
tile: uaccess s/might_sleep/might_fault/
powerpc: uaccess s/might_sleep/might_fault/
mn10300: uaccess s/might_sleep/might_fault/
microblaze: uaccess s/might_sleep/might_fault/
m32r: uaccess s/might_sleep/might_fault/
frv: uaccess s/might_sleep/might_fault/
arm64: uaccess s/might_sleep/might_fault/
asm-generic: uaccess s/might_sleep/might_fault/
Pull locking changes from Ingo Molnar:
"Four miscellanous standalone fixes for futexes, rtmutexes and
Kconfig.locks."
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Use freezable blocking call
futex: Take hugepages into account when generating futex_key
rtmutex: Document rt_mutex_adjust_prio_chain()
locking: Fix copy/paste errors of "ARCH_INLINE_*_UNLOCK_BH"
Here's the big driver core merge for 3.11-rc1
Lots of little things, and larger firmware subsystem updates, all
described in the shortlog. Nice thing here is that we finally get rid
of CONFIG_HOTPLUG, after 10+ years, thanks to Stephen Rohtwell (it had
been always on for a number of kernel releases, now it's just removed.)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here's the big driver core merge for 3.11-rc1
Lots of little things, and larger firmware subsystem updates, all
described in the shortlog. Nice thing here is that we finally get rid
of CONFIG_HOTPLUG, after 10+ years, thanks to Stephen Rohtwell (it had
been always on for a number of kernel releases, now it's just
removed)"
* tag 'driver-core-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (27 commits)
driver core: device.h: fix doc compilation warnings
firmware loader: fix another compile warning with PM_SLEEP unset
build some drivers only when compile-testing
firmware loader: fix compile warning with PM_SLEEP set
kobject: sanitize argument for format string
sysfs_notify is only possible on file attributes
firmware loader: simplify holding module for request_firmware
firmware loader: don't export cache_firmware and uncache_firmware
drivers/base: Use attribute groups to create sysfs memory files
firmware loader: fix compile warning
firmware loader: fix build failure with !CONFIG_FW_LOADER_USER_HELPER
Documentation: Updated broken link in HOWTO
Finally eradicate CONFIG_HOTPLUG
driver core: firmware loader: kill FW_ACTION_NOHOTPLUG requests before suspend
driver core: firmware loader: don't cache FW_ACTION_NOHOTPLUG firmware
Documentation: Tidy up some drivers/base/core.c kerneldoc content.
platform_device: use a macro instead of platform_driver_register
firmware: move EXPORT_SYMBOL annotations
firmware: Avoid deadlock of usermodehelper lock at shutdown
dell_rbu: Select CONFIG_FW_LOADER_USER_HELPER explicitly
...
category, of note is a fix for on-line resizing file systems where the
block size is smaller than the page size (i.e., file systems 1k blocks
on x86, or more interestingly file systems with 4k blocks on Power or
ia64 systems.)
In the cleanup category, the ext4's punch hole implementation was
significantly improved by Lukas Czerner, and now supports bigalloc
file systems. In addition, Jan Kara significantly cleaned up the
write submission code path. We also improved error checking and added
a few sanity checks.
In the optimizations category, two major optimizations deserve
mention. The first is that ext4_writepages() is now used for
nodelalloc and ext3 compatibility mode. This allows writes to be
submitted much more efficiently as a single bio request, instead of
being sent as individual 4k writes into the block layer (which then
relied on the elevator code to coalesce the requests in the block
queue). Secondly, the extent cache shrink mechanism, which was
introduce in 3.9, no longer has a scalability bottleneck caused by the
i_es_lru spinlock. Other optimizations include some changes to reduce
CPU usage and to avoid issuing empty commits unnecessarily.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 update from Ted Ts'o:
"Lots of bug fixes, cleanups and optimizations. In the bug fixes
category, of note is a fix for on-line resizing file systems where the
block size is smaller than the page size (i.e., file systems 1k blocks
on x86, or more interestingly file systems with 4k blocks on Power or
ia64 systems.)
In the cleanup category, the ext4's punch hole implementation was
significantly improved by Lukas Czerner, and now supports bigalloc
file systems. In addition, Jan Kara significantly cleaned up the
write submission code path. We also improved error checking and added
a few sanity checks.
In the optimizations category, two major optimizations deserve
mention. The first is that ext4_writepages() is now used for
nodelalloc and ext3 compatibility mode. This allows writes to be
submitted much more efficiently as a single bio request, instead of
being sent as individual 4k writes into the block layer (which then
relied on the elevator code to coalesce the requests in the block
queue). Secondly, the extent cache shrink mechanism, which was
introduce in 3.9, no longer has a scalability bottleneck caused by the
i_es_lru spinlock. Other optimizations include some changes to reduce
CPU usage and to avoid issuing empty commits unnecessarily."
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (86 commits)
ext4: optimize starting extent in ext4_ext_rm_leaf()
jbd2: invalidate handle if jbd2_journal_restart() fails
ext4: translate flag bits to strings in tracepoints
ext4: fix up error handling for mpage_map_and_submit_extent()
jbd2: fix theoretical race in jbd2__journal_restart
ext4: only zero partial blocks in ext4_zero_partial_blocks()
ext4: check error return from ext4_write_inline_data_end()
ext4: delete unnecessary C statements
ext3,ext4: don't mess with dir_file->f_pos in htree_dirblock_to_tree()
jbd2: move superblock checksum calculation to jbd2_write_superblock()
ext4: pass inode pointer instead of file pointer to punch hole
ext4: improve free space calculation for inline_data
ext4: reduce object size when !CONFIG_PRINTK
ext4: improve extent cache shrink mechanism to avoid to burn CPU time
ext4: implement error handling of ext4_mb_new_preallocation()
ext4: fix corruption when online resizing a fs with 1K block size
ext4: delete unused variables
ext4: return FIEMAP_EXTENT_UNKNOWN for delalloc extents
jbd2: remove debug dependency on debug_fs and update Kconfig help text
jbd2: use a single printk for jbd_debug()
...
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Merge tag 'v3.10' into next
Merge 3.10 in order to get some of the last minute powerpc
changes, resolve conflicts and add additional fixes on top
of them.
Zhang Yanfei