In AIM7 runs, recent kernels start swapping out anonymous pages well
before they should. This is due to shrink_list falling through to
shrink_inactive_list if !inactive_anon_is_low(zone, sc), when all we
really wanted to do is pre-age some anonymous pages to give them extra
time to be referenced while on the inactive list.
The obvious fix is to make sure that shrink_list does not fall through to
scanning/reclaiming inactive pages when we called it to scan one of the
active lists.
This change should be safe because the loop in shrink_zone ensures that we
will still shrink the anon and file inactive lists whenever we should.
[kosaki.motohiro@jp.fujitsu.com: inactive_file_is_low() should be inactive_anon_is_low()]
Reported-by: Larry Woodman <lwoodman@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tomasz Chmielewski <mangoo@wpkg.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
shrink_all_zone() was introduced by commit d6277db4ab (swsusp: rework
memory shrinker) for hibernate performance improvement. and
sc.swap_cluster_max was introduced by commit a06fe4d307 (Speed freeing
memory for suspend).
commit a06fe4d307 said
Without the patch:
Freed 14600 pages in 1749 jiffies = 32.61 MB/s (Anomolous!)
Freed 88563 pages in 14719 jiffies = 23.50 MB/s
Freed 205734 pages in 32389 jiffies = 24.81 MB/s
With the patch:
Freed 68252 pages in 496 jiffies = 537.52 MB/s
Freed 116464 pages in 569 jiffies = 798.54 MB/s
Freed 209699 pages in 705 jiffies = 1161.89 MB/s
At that time, their patch was pretty worth. However, Modern Hardware
trend and recent VM improvement broke its worth. From several reason, I
think we should remove shrink_all_zones() at all.
detail:
1) Old days, shrink_zone()'s slowness was mainly caused by stupid io-throttle
at no i/o congestion.
but current shrink_zone() is sane, not slow.
2) shrink_all_zone() try to shrink all pages at a time. but it doesn't works
fine on numa system.
example)
System has 4GB memory and each node have 2GB. and hibernate need 1GB.
optimal)
steal 500MB from each node.
shrink_all_zones)
steal 1GB from node-0.
Oh, Cache balancing logic was broken. ;)
Unfortunately, Desktop system moved ahead NUMA at nowadays.
(Side note, if hibernate require 2GB, shrink_all_zones() never success
on above machine)
3) if the node has several I/O flighting pages, shrink_all_zones() makes
pretty bad result.
schenario) hibernate need 1GB
1) shrink_all_zones() try to reclaim 1GB from Node-0
2) but it only reclaimed 990MB
3) stupidly, shrink_all_zones() try to reclaim 1GB from Node-1
4) it reclaimed 990MB
Oh, well. it reclaimed twice much than required.
In the other hand, current shrink_zone() has sane baling out logic.
then, it doesn't make overkill reclaim. then, we lost shrink_zones()'s risk.
4) SplitLRU VM always keep active/inactive ratio very carefully. inactive list only
shrinking break its assumption. it makes unnecessary OOM risk. it obviously suboptimal.
Now, shrink_all_memory() is only the wrapper function of do_try_to_free_pages().
it bring good reviewability and debuggability, and solve above problems.
side note: Reclaim logic unificication makes two good side effect.
- Fix recursive reclaim bug on shrink_all_memory().
it did forgot to use PF_MEMALLOC. it mean the system be able to stuck into deadlock.
- Now, shrink_all_memory() got lockdep awareness. it bring good debuggability.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
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, sc.scap_cluster_max has double meanings.
1) reclaim batch size as isolate_lru_pages()'s argument
2) reclaim baling out thresolds
The two meanings pretty unrelated. Thus, Let's separate it.
this patch doesn't change any behavior.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.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>
If reclaim fails to make sufficient progress, the priority is raised.
Once the priority is higher, kswapd starts waiting on congestion.
However, if the zone is below the min watermark then kswapd needs to
continue working without delay as there is a danger of an increased rate
of GFP_ATOMIC allocation failure.
This patch changes the conditions under which kswapd waits on congestion
by only going to sleep if the min watermarks are being met.
[mel@csn.ul.ie: add stats to track how relevant the logic is]
[mel@csn.ul.ie: make kswapd only check its own zones and rename the relevant counters]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After kswapd balances all zones in a pgdat, it goes to sleep. In the
event of no IO congestion, kswapd can go to sleep very shortly after the
high watermark was reached. If there are a constant stream of allocations
from parallel processes, it can mean that kswapd went to sleep too quickly
and the high watermark is not being maintained for sufficient length time.
This patch makes kswapd go to sleep as a two-stage process. It first
tries to sleep for HZ/10. If it is woken up by another process or the
high watermark is no longer met, it's considered a premature sleep and
kswapd continues work. Otherwise it goes fully to sleep.
This adds more counters to distinguish between fast and slow breaches of
watermarks. A "fast" premature sleep is one where the low watermark was
hit in a very short time after kswapd going to sleep. A "slow" premature
sleep indicates that the high watermark was breached after a very short
interval.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Frans Pop <elendil@planet.nl>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 543ade1fc9 ("Streamline generic_file_* interfaces and filemap
cleanups") removed generic_file_write() in filemap. Change the comment in
vmscan pageout() to __generic_file_aio_write().
Signed-off-by: Vincent Li <macli@brc.ubc.ca>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Isolators putting a page back to the LRU do not hold the page lock, and if
the page is mlocked, another thread might munlock it concurrently.
Expecting this, the putback code re-checks the evictability of a page when
it just moved it to the unevictable list in order to correct its decision.
The problem, however, is that ordering is not garuanteed between setting
PG_lru when moving the page to the list and checking PG_mlocked
afterwards:
#0: #1
spin_lock()
if (TestClearPageMlocked())
if (PageLRU())
move to evictable list
SetPageLRU()
spin_unlock()
if (!PageMlocked())
move to evictable list
The PageMlocked() check may get reordered before SetPageLRU() in #0,
resulting in #0 not moving the still mlocked page, and in #1 failing to
isolate and move the page as well. The page is now stranded on the
unevictable list.
The race condition is very unlikely. The consequence currently is one
page falling off the reclaim grid and eventually getting freed with
PG_unevictable set, which triggers a warning in the page allocator.
TestClearPageMlocked() in #1 already provides full memory barrier
semantics.
This patch adds an explicit full barrier to force ordering between
SetPageLRU() and PageMlocked() so that either one of the competitors
rescues the page.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is possible to have !Anon but SwapBacked pages, and some apps could
create huge number of such pages with MAP_SHARED|MAP_ANONYMOUS. These
pages go into the ANON lru list, and hence shall not be protected: we only
care mapped executable files. Failing to do so may trigger OOM.
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'writeback' of git://git.kernel.dk/linux-2.6-block:
writeback: writeback_inodes_sb() should use bdi_start_writeback()
writeback: don't delay inodes redirtied by a fast dirtier
writeback: make the super_block pinning more efficient
writeback: don't resort for a single super_block in move_expired_inodes()
writeback: move inodes from one super_block together
writeback: get rid to incorrect references to pdflush in comments
writeback: improve readability of the wb_writeback() continue/break logic
writeback: cleanup writeback_single_inode()
writeback: kupdate writeback shall not stop when more io is possible
writeback: stop background writeback when below background threshold
writeback: balance_dirty_pages() shall write more than dirtied pages
fs: Fix busyloop in wb_writeback()
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (21 commits)
HWPOISON: Enable error_remove_page on btrfs
HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs
HWPOISON: Add madvise() based injector for hardware poisoned pages v4
HWPOISON: Enable error_remove_page for NFS
HWPOISON: Enable .remove_error_page for migration aware file systems
HWPOISON: The high level memory error handler in the VM v7
HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process
HWPOISON: shmem: call set_page_dirty() with locked page
HWPOISON: Define a new error_remove_page address space op for async truncation
HWPOISON: Add invalidate_inode_page
HWPOISON: Refactor truncate to allow direct truncating of page v2
HWPOISON: check and isolate corrupted free pages v2
HWPOISON: Handle hardware poisoned pages in try_to_unmap
HWPOISON: Use bitmask/action code for try_to_unmap behaviour
HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2
HWPOISON: Add poison check to page fault handling
HWPOISON: Add basic support for poisoned pages in fault handler v3
HWPOISON: Add new SIGBUS error codes for hardware poison signals
HWPOISON: Add support for poison swap entries v2
HWPOISON: Export some rmap vma locking to outside world
...
Implement reclaim from groups over their soft limit
Permit reclaim from memory cgroups on contention (via the direct reclaim
path).
memory cgroup soft limit reclaim finds the group that exceeds its soft
limit by the largest number of pages and reclaims pages from it and then
reinserts the cgroup into its correct place in the rbtree.
Add additional checks to mem_cgroup_hierarchical_reclaim() to detect long
loops in case all swap is turned off. The code has been refactored and
the loop check (loop < 2) has been enhanced for soft limits. For soft
limits, we try to do more targetted reclaim. Instead of bailing out after
two loops, the routine now reclaims memory proportional to the size by
which the soft limit is exceeded. The proportion has been empirically
determined.
[akpm@linux-foundation.org: build fix]
[kamezawa.hiroyu@jp.fujitsu.com: fix softlimit css refcnt handling]
[nishimura@mxp.nes.nec.co.jp: refcount of the "victim" should be decremented before exiting the loop]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For mem_cgroup, shrink_zone() may call shrink_list() with nr_to_scan=1, in
which case shrink_list() _still_ calls isolate_pages() with the much
larger SWAP_CLUSTER_MAX. It effectively scales up the inactive list scan
rate by up to 32 times.
For example, with 16k inactive pages and DEF_PRIORITY=12, (16k >> 12)=4.
So when shrink_zone() expects to scan 4 pages in the active/inactive list,
the active list will be scanned 4 pages, while the inactive list will be
(over) scanned SWAP_CLUSTER_MAX=32 pages in effect. And that could break
the balance between the two lists.
It can further impact the scan of anon active list, due to the anon
active/inactive ratio rebalance logic in balance_pgdat()/shrink_zone():
inactive anon list over scanned => inactive_anon_is_low() == TRUE
=> shrink_active_list()
=> active anon list over scanned
So the end result may be
- anon inactive => over scanned
- anon active => over scanned (maybe not as much)
- file inactive => over scanned
- file active => under scanned (relatively)
The accesses to nr_saved_scan are not lock protected and so not 100%
accurate, however we can tolerate small errors and the resulted small
imbalanced scan rates between zones.
Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
page_is_file_cache() has been used for both boolean checks and LRU
arithmetic, which was always a bit weird.
Now that page_lru_base_type() exists for LRU arithmetic, make
page_is_file_cache() a real predicate function and adjust the
boolean-using callsites to drop those pesky double negations.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Huang Shijie
Rik van Riel
KOSAKI Motohiro
Mel Gorman
Vincent Li
David Rientjes
Johannes Weiner
Wu Fengguang
Linus Torvalds
Jens Axboe
Alexey Dobriyan
Balbir Singh