- 17 Jun, 2009 40 commits
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Mel Gorman authored
On NUMA machines, the administrator can configure zone_reclaim_mode that is a more targetted form of direct reclaim. On machines with large NUMA distances for example, a zone_reclaim_mode defaults to 1 meaning that clean unmapped pages will be reclaimed if the zone watermarks are not being met. There is a heuristic that determines if the scan is worthwhile but it is possible that the heuristic will fail and the CPU gets tied up scanning uselessly. Detecting the situation requires some guesswork and experimentation so this patch adds a counter "zreclaim_failed" to /proc/vmstat. If during high CPU utilisation this counter is increasing rapidly, then the resolution to the problem may be to set /proc/sys/vm/zone_reclaim_mode to 0. [akpm@linux-foundation.org: name things consistently] Signed-off-by:
Mel Gorman <mel@csn.ul.ie> Reviewed-by:
Rik van Riel <riel@redhat.com> Cc: Christoph Lameter <cl@linux-foundation.org> Reviewed-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: <stable@kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Mel Gorman authored
On NUMA machines, the administrator can configure zone_reclaim_mode that is a more targetted form of direct reclaim. On machines with large NUMA distances for example, a zone_reclaim_mode defaults to 1 meaning that clean unmapped pages will be reclaimed if the zone watermarks are not being met. The problem is that zone_reclaim() failing at all means the zone gets marked full. This can cause situations where a zone is usable, but is being skipped because it has been considered full. Take a situation where a large tmpfs mount is occuping a large percentage of memory overall. The pages do not get cleaned or reclaimed by zone_reclaim(), but the zone gets marked full and the zonelist cache considers them not worth trying in the future. This patch makes zone_reclaim() return more fine-grained information about what occured when zone_reclaim() failued. The zone only gets marked full if it really is unreclaimable. If it's a case that the scan did not occur or if enough pages were not reclaimed with the limited reclaim_mode, then the zone is simply skipped. There is a side-effect to this patch. Currently, if zone_reclaim() successfully reclaimed SWAP_CLUSTER_MAX, an allocation attempt would go ahead. With this patch applied, zone watermarks are rechecked after zone_reclaim() does some work. This bug was introduced by commit 9276b1bc ("memory page_alloc zonelist caching speedup") way back in 2.6.19 when the zonelist_cache was introduced. It was not intended that zone_reclaim() aggressively consider the zone to be full when it failed as full direct reclaim can still be an option. Due to the age of the bug, it should be considered a -stable candidate. Signed-off-by:
Wu Fengguang <fengguang.wu@intel.com> Reviewed-by:
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Mel Gorman authored
A bug was brought to my attention against a distro kernel but it affects mainline and I believe problems like this have been reported in various guises on the mailing lists although I don't have specific examples at the moment. The reported problem was that malloc() stalled for a long time (minutes in some cases) if a large tmpfs mount was occupying a large percentage of memory overall. The pages did not get cleaned or reclaimed by zone_reclaim() because the zone_reclaim_mode was unsuitable, but the lists are uselessly scanned frequencly making the CPU spin at near 100%. This patchset intends to address that bug and bring the behaviour of zone_reclaim() more in line with expectations which were noticed during investigation. It is based on top of mmotm and takes advantage of Kosaki's work with respect to zone_reclaim(). Patch 1 fixes the heuristics that zone_reclaim() uses to determine if the scan should go ahead. The broken heuristic is what was causing the malloc() stall as it uselessly scanned the LRU constantly. Currently, zone_reclaim is assuming zone_reclaim_mode is 1 and historically it could not deal with tmpfs pages at all. This fixes up the heuristic so that an unnecessary scan is more likely to be correctly avoided. Patch 2 notes that zone_reclaim() returning a failure automatically means the zone is marked full. This is not always true. It could have failed because the GFP mask or zone_reclaim_mode were unsuitable. Patch 3 introduces a counter zreclaim_failed that will increment each time the zone_reclaim scan-avoidance heuristics fail. If that counter is rapidly increasing, then zone_reclaim_mode should be set to 0 as a temporarily resolution and a bug reported because the scan-avoidance heuristic is still broken. This patch: On NUMA machines, the administrator can configure zone_reclaim_mode that is a more targetted form of direct reclaim. On machines with large NUMA distances for example, a zone_reclaim_mode defaults to 1 meaning that clean unmapped pages will be reclaimed if the zone watermarks are not being met. There is a heuristic that determines if the scan is worthwhile but the problem is that the heuristic is not being properly applied and is basically assuming zone_reclaim_mode is 1 if it is enabled. The lack of proper detection can manfiest as high CPU usage as the LRU list is scanned uselessly. Historically, once enabled it was depending on NR_FILE_PAGES which may include swapcache pages that the reclaim_mode cannot deal with. Patch vmscan-change-the-number-of-the-unmapped-files-in-zone-reclaim.patch by Kosaki Motohiro noted that zone_page_state(zone, NR_FILE_PAGES) included pages that were not file-backed such as swapcache and made a calculation based on the inactive, active and mapped files. This is far superior when zone_reclaim==1 but if RECLAIM_SWAP is set, then NR_FILE_PAGES is a reasonable starting figure. This patch alters how zone_reclaim() works out how many pages it might be able to reclaim given the current reclaim_mode. If RECLAIM_SWAP is set in the reclaim_mode it will either consider NR_FILE_PAGES as potential candidates or else use NR_{IN}ACTIVE}_PAGES-NR_FILE_MAPPED to discount swapcache and other non-file-backed pages. If RECLAIM_WRITE is not set, then NR_FILE_DIRTY number of pages are not candidates. If RECLAIM_SWAP is not set, then NR_FILE_MAPPED are not. [kosaki.motohiro@jp.fujitsu.com: Estimate unmapped pages minus tmpfs pages] [fengguang.wu@intel.com: Fix underflow problem in Kosaki's estimate] Signed-off-by:Christoph Lameter <cl@linux-foundation.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: <stable@kernel.org> Signed-off-by:
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Wu Fengguang authored
1) I_FREEING tests should be coupled with I_CLEAR The two I_FREEING tests are racy because clear_inode() can set i_state to I_CLEAR between the clear of I_SYNC and the test of I_FREEING. 2) skip I_WILL_FREE inodes in generic_sync_sb_inodes() to avoid possible races with generic_forget_inode() generic_forget_inode() sets I_WILL_FREE call writeback on its own, so generic_sync_sb_inodes() shall not try to step in and create possible races: generic_forget_inode inode->i_state |= I_WILL_FREE; spin_unlock(&inode_lock); generic_sync_sb_inodes() spin_lock(&inode_lock); __iget(inode); __writeback_single_inode // see non zero i_count may WARN here ==> WARN_ON(inode->i_state & I_WILL_FREE); spin_unlock(&inode_lock); may call generic_forget_inode again ==> iput(inode); The above race and warning didn't turn up because writeback_inodes() holds the s_umount lock, so generic_forget_inode() finds MS_ACTIVE and returns early. But we are not sure the UBIFS calls and future callers will guarantee that. So skip I_WILL_FREE inodes for the sake of safety. Cc: Eric Sandeen <sandeen@sandeen.net> Acked-by:Jeff Layton <jlayton@redhat.com> Cc: Masayoshi MIZUMA <m.mizuma@jp.fujitsu.com> Signed-off-by:
Jan Kara <jack@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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David Rientjes authored
When a task is chosen for oom kill and is found to be PF_EXITING, __oom_kill_task() is called to elevate the task's timeslice and give it access to memory reserves so that it may quickly exit. This privilege is unnecessary, however, if the task has already detached its mm. Although its possible for the mm to become detached later since task_lock() is not held, __oom_kill_task() will simply be a no-op in such circumstances. Subsequently, it is no longer necessary to warn about killing mm-less tasks since it is a no-op. Signed-off-by:
David Rientjes <rientjes@google.com> Acked-by:
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Daisuke Nishimura authored
Commit 2e2e4259 ("vmscan,memcg: reintroduce sc->may_swap) add may_swap flag and handle it at get_scan_ratio(). But the result of get_scan_ratio() is ignored when priority == 0, so anon lru is scanned even if may_swap == 0 or nr_swap_pages == 0. IMHO, this is not an expected behavior. As for memcg especially, because of this behavior many and many pages are swapped-out just in vain when oom is invoked by mem+swap limit. This patch is for handling may_swap flag more strictly. Signed-off-by:
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Reviewed-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by:
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Wu Fengguang authored
The "move pages to active list" and "move pages to inactive list" code blocks are mostly identical and can be served by a function. Thanks to Andrew Morton for pointing this out. Note that buffer_heads_over_limit check will also be carried out for re-activated pages, which is slightly different from pre-2.6.28 kernels. Also, Rik's "vmscan: evict use-once pages first" patch could totally stop scans of active file list when memory pressure is low. So the net effect could be, the number of buffer heads is now more likely to grow large. However that's fine according to Johannes' comments: I don't think that this could be harmful. We just preserve the buffer mappings of what we consider the working set and with low memory pressure, as you say, this set is not big. As to stripping of reactivated pages: the only pages we re-activate for now are those VM_EXEC mapped ones. Since we don't expect IO from or to these pages, removing the buffer mappings in case they grow too large should be okay, I guess. Cc: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by:
Peter Zijlstra <peterz@infradead.org> Reviewed-by:
Minchan Kim <minchan.kim@gmail.com> Reviewed-by:
Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
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Wu Fengguang authored
Protect referenced PROT_EXEC mapped pages from being deactivated. PROT_EXEC(or its internal presentation VM_EXEC) pages normally belong to some currently running executables and their linked libraries, they shall really be cached aggressively to provide good user experiences. Thanks to Johannes Weiner for the advice to reuse the VMA walk in page_referenced() to get the PROT_EXEC bit. [more details] ( The consequences of this patch will have to be discussed together with Rik van Riel's recent patch "vmscan: evict use-once pages first". ) ( Some of the good points and insights are taken into this changelog. Thanks to all the involved people for the great LKML discussions. ) the problem =========== For a typical desktop, the most precious working set is composed of *actively accessed* (1) memory mapped executables (2) and their anonymous pages (3) and other files (4) and the dcache/icache/.. slabs while the least important data are (5) infrequently used or use-once files For a typical desktop, one major problem is busty and large amount of (5) use-once files flushing out the working set. Inside the working set, (4) dcache/icache have already been too sticky ;-) So we only have to care (2) anonymous and (1)(3) file pages. anonymous pages =============== Anonymous pages are effectively immune to the streaming IO attack, because we now have separate file/anon LRU lists. When the use-once files crowd into the file LRU, the list's "quality" is significantly lowered. Therefore the scan balance policy in get_scan_ratio() will choose to scan the (low quality) file LRU much more frequently than the anon LRU. file pages ========== Rik proposed to *not* scan the active file LRU when the inactive list grows larger than active list. This guarantees that when there are use-once streaming IO, and the working set is not too large(so that active_size < inactive_size), the active file LRU will *not* be scanned at all. So the not-too-large working set can be well protected. But there are also situations where the file working set is a bit large so that (active_size >= inactive_size), or the streaming IOs are not purely use-once. In these cases, the active list will be scanned slowly. Because the current shrink_active_list() policy is to deactivate active pages regardless of their referenced bits. The deactivated pages become susceptible to the streaming IO attack: the inactive list could be scanned fast (500MB / 50MBps = 10s) so that the deactivated pages don't have enough time to get re-referenced. Because a user tend to switch between windows in intervals from seconds to minutes. This patch holds mapped executable pages in the active list as long as they are referenced during each full scan of the active list. Because the active list is normally scanned much slower, they get longer grace time (eg. 100s) for further references, which better matches the pace of user operations. Therefore this patch greatly prolongs the in-cache time of executable code, when there are moderate memory pressures. before patch: guaranteed to be cached if reference intervals < I after patch: guaranteed to be cached if reference intervals < I+A (except when randomly reclaimed by the lumpy reclaim) where A = time to fully scan the active file LRU I = time to fully scan the inactive file LRU Note that normally A >> I. side effects ============ This patch is safe in general, it restores the pre-2.6.28 mmap() behavior but in a much smaller and well targeted scope. One may worry about some one to abuse the PROT_EXEC heuristic. But as Andrew Morton stated, there are other tricks to getting that sort of boost. Another concern is the PROT_EXEC mapped pages growing large in rare cases, and therefore hurting reclaim efficiency. But a sane application targeted for large audience will never use PROT_EXEC for data mappings. If some home made application tries to abuse that bit, it shall be aware of the consequences. If it is abused to scale of 2/3 total memory, it gains nothing but overheads. benchmarks ========== 1) memory tight desktop 1.1) brief summary - clock time and major faults are reduced by 50%; - pswpin numbers are reduced to ~1/3. That means X desktop responsiveness is doubled under high memory/swap pressure. 1.2) test scenario - nfsroot gnome desktop with 512M physical memory - run some programs, and switch between the existing windows after starting each new program. 1.3) progress timing (seconds) before after programs 0.02 0.02 N xeyes 0.75 0.76 N firefox 2.02 1.88 N nautilus 3.36 3.17 N nautilus --browser 5.26 4.89 N gthumb 7.12 6.47 N gedit 9.22 8.16 N xpdf /usr/share/doc/shared-mime-info/shared-mime-info-spec.pdf 13.58 12.55 N xterm 15.87 14.57 N mlterm 18.63 17.06 N gnome-terminal 21.16 18.90 N urxvt 26.24 23.48 N gnome-system-monitor 28.72 26.52 N gnome-help 32.15 29.65 N gnome-dictionary 39.66 36.12 N /usr/games/sol 43.16 39.27 N /usr/games/gnometris 48.65 42.56 N /usr/games/gnect 53.31 47.03 N /usr/games/gtali 58.60 52.05 N /usr/games/iagno 65.77 55.42 N /usr/games/gnotravex 70.76 61.47 N /usr/games/mahjongg 76.15 67.11 N /usr/games/gnome-sudoku 86.32 75.15 N /usr/games/glines 92.21 79.70 N /usr/games/glchess 103.79 88.48 N /usr/games/gnomine 113.84 96.51 N /usr/games/gnotski 124.40 102.19 N /usr/games/gnibbles 137.41 114.93 N /usr/games/gnobots2 155.53 125.02 N /usr/games/blackjack 179.85 135.11 N /usr/games/same-gnome 224.49 154.50 N /usr/bin/gnome-window-properties 248.44 162.09 N /usr/bin/gnome-default-applications-properties 282.62 173.29 N /usr/bin/gnome-at-properties 323.72 188.21 N /usr/bin/gnome-typing-monitor 363.99 199.93 N /usr/bin/gnome-at-visual 394.21 206.95 N /usr/bin/gnome-sound-properties 435.14 224.49 N /usr/bin/gnome-at-mobility 463.05 234.11 N /usr/bin/gnome-keybinding-properties 503.75 248.59 N /usr/bin/gnome-about-me 554.00 276.27 N /usr/bin/gnome-display-properties 615.48 304.39 N /usr/bin/gnome-network-preferences 693.03 342.01 N /usr/bin/gnome-mouse-properties 759.90 388.58 N /usr/bin/gnome-appearance-properties 937.90 508.47 N /usr/bin/gnome-control-center 1109.75 587.57 N /usr/bin/gnome-keyboard-properties 1399.05 758.16 N : oocalc 1524.64 830.03 N : oodraw 1684.31 900.03 N : ooimpress 1874.04 993.91 N : oomath 2115.12 1081.89 N : ooweb 2369.02 1161.99 N : oowriter Note that the last ": oo*" commands are actually commented out. 1.4) vmstat numbers (some relevant ones are marked with *) before after nr_free_pages 1293 3898 nr_inactive_anon 59956 53460 nr_active_anon 26815 30026 nr_inactive_file 2657 3218 nr_active_file 2019 2806 nr_unevictable 4 4 nr_mlock 4 4 nr_anon_pages 26706 27859 *nr_mapped 3542 4469 nr_file_pages 72232 67681 nr_dirty 1 0 nr_writeback 123 19 nr_slab_reclaimable 3375 3534 nr_slab_unreclaimable 11405 10665 nr_page_table_pages 8106 7864 nr_unstable 0 0 nr_bounce 0 0 *nr_vmscan_write 394776 230839 nr_writeback_temp 0 0 numa_hit 6843353 3318676 numa_miss 0 0 numa_foreign 0 0 numa_interleave 1719 1719 numa_local 6843353 3318676 numa_other 0 0 *pgpgin 5954683 2057175 *pgpgout 1578276 922744 *pswpin 1486615 512238 *pswpout 394568 230685 pgalloc_dma 277432 56602 pgalloc_dma32 6769477 3310348 pgalloc_normal 0 0 pgalloc_movable 0 0 pgfree 7048396 3371118 pgactivate 2036343 1471492 pgdeactivate 2189691 1612829 pgfault 3702176 3100702 *pgmajfault 452116 201343 pgrefill_dma 12185 7127 pgrefill_dma32 334384 653703 pgrefill_normal 0 0 pgrefill_movable 0 0 pgsteal_dma 74214 22179 pgsteal_dma32 3334164 1638029 pgsteal_normal 0 0 pgsteal_movable 0 0 pgscan_kswapd_dma 1081421 1216199 pgscan_kswapd_dma32 58979118 46002810 pgscan_kswapd_normal 0 0 pgscan_kswapd_movable 0 0 pgscan_direct_dma 2015438 1086109 pgscan_direct_dma32 55787823 36101597 pgscan_direct_normal 0 0 pgscan_direct_movable 0 0 pginodesteal 3461 7281 slabs_scanned 564864 527616 kswapd_steal 2889797 1448082 kswapd_inodesteal 14827 14835 pageoutrun 43459 21562 allocstall 9653 4032 pgrotated 384216 228631 1.5) free numbers at the end of the tests before patch: total used free shared buffers cached Mem: 474 467 7 0 0 236 -/+ buffers/cache: 230 243 Swap: 1023 418 605 after patch: total used free shared buffers cached Mem: 474 457 16 0 0 236 -/+ buffers/cache: 221 253 Swap: 1023 404 619 2) memory flushing in a file server 2.1) brief summary The number of major faults from 50 to 3 during 10% cache hot reads. That means this patch successfully stops major faults when the active file list is slowly scanned when there are partially cache hot streaming IO. 2.2) test scenario Do 100000 pread(size=110 pages, offset=(i*100) pages), where 10% of the pages will be activated: for i in `seq 0 100 10000000`; do echo $i 110; done > pattern-hot-10 iotrace.rb --load pattern-hot-10 --play /b/sparse vmmon nr_mapped nr_active_file nr_inactive_file pgmajfault pgdeactivate pgfree and monitor /proc/vmstat during the time. The test box has 2G memory. I carried out tests on fresh booted console as well as X desktop, and fetched the vmstat numbers on (1) begin: shortly after the big read IO starts; (2) end: just before the big read IO stops; (3) restore: the big read IO stops and the zsh working set restored (4) restore X: after IO, switch back and forth between the urxvt and firefox windows to restore their working set. 2.3) console mode results nr_mapped nr_active_file nr_inactive_file pgmajfault pgdeactivate pgfree 2.6.29 VM_EXEC protection ON: begin: 2481 2237 8694 630 0 574299 end: 275 231976 233914 633 776271 20933042 restore: 370 232154 234524 691 777183 20958453 2.6.29 VM_EXEC protection ON (second run): begin: 2434 2237 8493 629 0 574195 end: 284 231970 233536 632 771918 20896129 restore: 399 232218 234789 690 774526 20957909 2.6.30-rc4-mm VM_EXEC protection OFF: begin: 2479 2344 9659 210 0 579643 end: 284 232010 234142 260 772776 20917184 restore: 379 232159 234371 301 774888 20967849 The above console numbers show that - The startup pgmajfault of 2.6.30-rc4-mm is merely 1/3 that of 2.6.29. I'd attribute that improvement to the mmap readahead improvements :-) - The pgmajfault increment during the file copy is 633-630=3 vs 260-210=50. That's a huge improvement - which means with the VM_EXEC protection logic, active mmap pages is pretty safe even under partially cache hot streaming IO. - when active:inactive file lru size reaches 1:1, their scan rates is 1:20.8 under 10% cache hot IO. (computed with formula Dpgdeactivate:Dpgfree) That roughly means the active mmap pages get 20.8 more chances to get re-referenced to stay in memory. - The absolute nr_mapped drops considerably to 1/9 during the big IO, and the dropped pages are mostly inactive ones. The patch has almost no impact in this aspect, that means it won't unnecessarily increase memory pressure. (In contrast, your 20% mmap protection ratio will keep them all, and therefore eliminate the extra 41 major faults to restore working set of zsh etc.) The iotrace.rb read throughput is 151.194384MB/s 284.198252s 100001x 450560b --load pattern-hot-10 --play /b/sparse which means the inactive list is rotated at the speed of 250MB/s, so a full scan of which takes about 3.5 seconds, while a full scan of active file list takes about 77 seconds. 2.4) X mode results We can reach roughly the same conclusions for X desktop: nr_mapped nr_active_file nr_inactive_file pgmajfault pgdeactivate pgfree 2.6.30-rc4-mm VM_EXEC protection ON: begin: 9740 8920 64075 561 0 678360 end: 768 218254 220029 565 798953 21057006 restore: 857 218543 220987 606 799462 21075710 restore X: 2414 218560 225344 797 799462 21080795 2.6.30-rc4-mm VM_EXEC protection OFF: begin: 9368 5035 26389 554 0 633391 end: 770 218449 221230 661 646472 17832500 restore: 1113 218466 220978 710 649881 17905235 restore X: 2687 218650 225484 947 802700 21083584 - the absolute nr_mapped drops considerably (to 1/13 of the original size) during the streaming IO. - the delta of pgmajfault is 3 vs 107 during IO, or 236 vs 393 during the whole process. Cc: Elladan <elladan@eskimo.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Lameter <cl@linux-foundation.org> Acked-by: -
Wu Fengguang authored
Collect vma->vm_flags of the VMAs that actually referenced the page. This is preparing for more informed reclaim heuristics, eg. to protect executable file pages more aggressively. For now only the VM_EXEC bit will be used by the caller. Thanks to Johannes, Peter and Minchan for all the good tips. Acked-by:
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Mel Gorman authored
The page allocation failure messages include a line that looks like page allocation failure. order:1, mode:0x4020 The mode is easy to translate but irritating for the lazy and a bit error prone. This patch adds a very simple helper script gfp-translate for the mode: portion of the page allocation failure messages. An example usage looks like mel@machina:~/linux-2.6 $ scripts/gfp-translate 0x4020 Source: /home/mel/linux-2.6 Parsing: 0x4020 #define __GFP_HIGH (0x20) /* Should access emergency pools? */ #define __GFP_COMP (0x4000) /* Add compound page metadata */ The script is not a work of art but it has come in handy for me a few times so I thought I would share. [akpm@linux-foundation.org: clarify an error message] Signed-off-by:
Pekka Enberg <penberg@cs.helsinki.fi> Cc: Christoph Hellwig <hch@infradead.org> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by:
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Sergei Trofimovich authored
As function shmem_file_setup does not modify/allocate/free/pass given filename - mark it as const. Signed-off-by:
Sergei Trofimovich <slyfox@inbox.ru> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by:
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Minchan Kim authored
The file argument resulted from address_space's readpage long time ago. We don't use it any more. Let's remove unnecessary argement. Signed-off-by:
Hugh Dickins <hugh.dickins@tiscali.co.uk> Reviewed-by:
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Minchan Kim authored
Hugh removed add_to_swap's gfp_mask argument. (mm: remove gfp_mask from add_to_swap) So we have to remove annotation of gfp_mask of the function. Signed-off-by:
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Yinghai Lu authored
SRAT tables may contains nodes of very small size. The arch code may decide to not activate such a node. However, currently the early boot code sets N_HIGH_MEMORY for such nodes. These nodes therefore seem to be active although these nodes have no present pages. For 64bit N_HIGH_MEMORY == N_NORMAL_MEMORY, so that works for 64 bit too Signed-off-by:
Yinghai Lu <Yinghai@kernel.org> Tested-by:
Jack Steiner <steiner@sgi.com> Acked-by:
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Mike Waychison authored
Remove __invalidate_mapping_pages atomic variant now that its sole caller can sleep (fixed in eccb95ce ("vfs: fix lock inversion in drop_pagecache_sb()")). This fixes softlockups that can occur while in the drop_caches path. Signed-off-by:
Mike Waychison <mikew@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Acked-by:
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David Rientjes authored
The oom killer must be invoked regardless of the order if the allocation is __GFP_NOFAIL, otherwise it will loop forever when reclaim fails to free some memory. Cc: Nick Piggin <npiggin@suse.de> Acked-by:
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David Rientjes authored
This moves the check for OOM_DISABLE to the badness heuristic so it is only necessary to hold task_lock() once. If the mm is OOM_DISABLE, the score is 0, which is also correctly exported via /proc/pid/oom_score. This requires that tasks with badness scores of 0 are prohibited from being oom killed, which makes sense since they would not allow for future memory freeing anyway. Since the oom_adj value is a characteristic of an mm and not a task, it is no longer necessary to check the oom_adj value for threads sharing the same memory (except when simply issuing SIGKILLs for threads in other thread groups). Cc: Nick Piggin <npiggin@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by:
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David Rientjes authored
The per-task oom_adj value is a characteristic of its mm more than the task itself since it's not possible to oom kill any thread that shares the mm. If a task were to be killed while attached to an mm that could not be freed because another thread were set to OOM_DISABLE, it would have needlessly been terminated since there is no potential for future memory freeing. This patch moves oomkilladj (now more appropriately named oom_adj) from struct task_struct to struct mm_struct. This requires task_lock() on a task to check its oom_adj value to protect against exec, but it's already necessary to take the lock when dereferencing the mm to find the total VM size for the badness heuristic. This fixes a livelock if the oom killer chooses a task and another thread sharing the same memory has an oom_adj value of OOM_DISABLE. This occurs because oom_kill_task() repeatedly returns 1 and refuses to kill the chosen task while select_bad_process() will repeatedly choose the same task during the next retry. Taking task_lock() in select_bad_process() to check for OOM_DISABLE and in oom_kill_task() to check for threads sharing the same memory will be removed in the next patch in this series where it will no longer be necessary. Writing to /proc/pid/oom_adj for a kthread will now return -EINVAL since these threads are immune from oom killing already. They simply report an oom_adj value of OOM_DISABLE. Cc: Nick Piggin <npiggin@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by:
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KAMEZAWA Hiroyuki authored
Presently we can know a swap entry is just used as SwapCache via swap_map, without looking up swap cache. Then, we have a chance to reuse swap-cache-only swap entries in get_swap_pages(). This patch tries to free swap-cache-only swap entries if swap is not enough. Note: We hit following path when swap_cluster code cannot find a free cluster. Then, vm_swap_full() is not only condition to allow the kernel to reclaim unused swap. Signed-off-by:
Balbir Singh <balbir@in.ibm.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Tested-by:
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KAMEZAWA Hiroyuki authored
This is a part of the patches for fixing memcg's swap accountinf leak. But, IMHO, not a bad patch even if no memcg. There are 2 kinds of references to swap. - reference from swap entry - reference from swap cache Then, - If there is swap cache && swap's refcnt is 1, there is only swap cache. (*) swapcount(entry) == 1 && find_get_page(swapper_space, entry) != NULL This counting logic have worked well for a long time. But considering that we cannot know there is a _real_ reference or not by swap_map[], current usage of counter is not very good. This patch adds a flag SWAP_HAS_CACHE and recored information that a swap entry has a cache or not. This will remove -1 magic used in swapfile.c and be a help to avoid unnecessary find_get_page(). Signed-off-by:
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KAMEZAWA Hiroyuki authored
In a following patch, the usage of swap cache is recorded into swap_map. This patch is for necessary interface changes to do that. 2 interfaces: - swapcache_prepare() - swapcache_free() are added for allocating/freeing refcnt from swap-cache to existing swap entries. But implementation itself is not changed under this patch. At adding swapcache_free(), memcg's hook code is moved under swapcache_free(). This is better than using scattered hooks. Signed-off-by:
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KOSAKI Motohiro authored
Currently, nobody wants to turn UNEVICTABLE_LRU off. Thus this configurability is unnecessary. Signed-off-by:
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Minchan Kim authored
Solve two problems. Whenever memory hotplug sucessfully happens, zone->present_pages have to be changed. 1) Now memory hotplug calls setup_per_zone_wmark_min only when online_pages called, not offline_pages. It breaks balance. 2) If zone->present_pages is changed, we also have to change zone->inactive_ratio. That's because inactive_ratio depends on zone->present_pages. Signed-off-by:
Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
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Minchan Kim authored
Factor the per-zone arithemetic inside setup_per_zone_inactive_ratio()'s loop into a a separate function, calculate_zone_inactive_ratio(). This function will be used in a later patch [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
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Minchan Kim authored
Change the names of two functions. It doesn't affect behavior. Presently, setup_per_zone_pages_min() changes low, high of zone as well as min. So a better name is setup_per_zone_wmarks(). That's because Mel changed zone->pages_[hig/low/min] to zone->watermark array in "page allocator: replace the watermark-related union in struct zone with a watermark[] array". * setup_per_zone_pages_min => setup_per_zone_wmarks Of course, we have to change init_per_zone_pages_min, too. There are not pages_min any more. * init_per_zone_pages_min => init_per_zone_wmark_min [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
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Christoph Lameter authored
page-allocator: use integer fields lookup for gfp_zone and check for errors in flags passed to the page allocator This simplifies the code in gfp_zone() and also keeps the ability of the compiler to use constant folding to get rid of gfp_zone processing. The lookup of the zone is done using a bitfield stored in an integer. So the code in gfp_zone is a simple extraction of bits from a constant bitfield. The compiler is generating a load of a constant into a register and then performs a shift and mask operation to get the zone from a gfp_t. No cachelines are touched and no branches have to be predicted by the compiler. We are doing some macro tricks here to convince the compiler to always do the constant folding if possible. Signed-off-by:
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Matthew Wilcox authored
If you're using a non-highmem architecture, passing an argument with the wrong type to kunmap() doesn't give you a warning because the ifdef doesn't check the type. Using a static inline function solves the problem nicely. Reported-by:
David Woodhouse <dwmw2@infradead.org> Signed-off-by:
Matthew Wilcox <willy@linux.intel.com> Signed-off-by:
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MinChan Kim authored
shrink_zone() can deactivate active anon pages even if we don't have a swap device. Many embedded products don't have a swap device. So the deactivation of anon pages is unnecessary. This patch prevents unnecessary deactivation of anon lru pages. But, it don't prevent aging of anon pages to swap out. Signed-off-by:
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Brice Goglin authored
migrate_prep() is fairly expensive (72us on 16-core barcelona 1.9GHz). Commit 3140a227 improved move_pages() throughput by breaking it into chunks, but it also made migrate_prep() be called once per chunk (every 128pages or so) instead of once per move_pages(). This patch reverts to calling migrate_prep() only once per chunk as we did before 2.6.29. It is also a followup to commit 0aedadf9 ("mm: move migrate_prep out from under mmap_sem"). This improves migration throughput on the above machine from 600MB/s to 750MB/s. Signed-off-by:
Brice Goglin <Brice.Goglin@inria.fr> Acked-by:
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Rafael J. Wysocki authored
Currently, the following scenario appears to be possible in theory: * Tasks are frozen for hibernation or suspend. * Free pages are almost exhausted. * Certain piece of code in the suspend code path attempts to allocate some memory using GFP_KERNEL and allocation order less than or equal to PAGE_ALLOC_COSTLY_ORDER. * __alloc_pages_internal() cannot find a free page so it invokes the OOM killer. * The OOM killer attempts to kill a task, but the task is frozen, so it doesn't die immediately. * __alloc_pages_internal() jumps to 'restart', unsuccessfully tries to find a free page and invokes the OOM killer. * No progress can be made. Although it is now hard to trigger during hibernation due to the memory shrinking carried out by the hibernation code, it is theoretically possible to trigger during suspend after the memory shrinking has been removed from that code path. Moreover, since memory allocations are going to be used for the hibernation memory shrinking, it will be even more likely to happen during hibernation. To prevent it from happening, introduce the oom_killer_disabled switch that will cause __alloc_pages_internal() to fail in the situations in which the OOM killer would have been called and make the freezer set this switch after tasks have been successfully frozen. [akpm@linux-foundation.org: be nicer to the namespace] Signed-off-by:
Rafael J. Wysocki <rjw@sisk.pl> Cc: Fengguang Wu <fengguang.wu@gmail.com> Cc: David Rientjes <rientjes@google.com> Acked-by:
Pavel Machek <pavel@ucw.cz> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by:
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Nick Piggin authored
The posix_madvise() function succeeds (and does nothing) when called with parameters (NULL, 0, -1); according to LSB tests, it should fail with EINVAL because -1 is not a valid flag. When called with a valid address and size, it correctly fails. So perform an initial check for valid flags first. Reported-by:
Jiri Dluhos <jdluhos@novell.com> Signed-off-by:
Nick Piggin <npiggin@suse.de> Reviewed-and-Tested-by:
WANG Cong <xiyou.wangcong@gmail.com> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by:
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Andrew Morton authored
__GFP_NOFAIL is a bad fiction. Allocations _can_ fail, and callers should detect and suitably handle this (and not by lamely moving the infinite loop up to the caller level either). Attempting to use __GFP_NOFAIL for a higher-order allocation is even worse, so add a once-off runtime check for this to slap people around for even thinking about trying it. Cc: David Rientjes <rientjes@google.com> Acked-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by:
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Magnus Damm authored
Since videobuf-dma-contig is designed to handle physically contiguous memory, this patch modifies the videobuf-dma-contig code to only accept a user space pointer to physically contiguous memory. For now only VM_PFNMAP vmas are supported, so forget hotplug. On SuperH Mobile we use this with our sh_mobile_ceu_camera driver together with various multimedia accelerator blocks that are exported to user space using UIO. The UIO kernel code exports physically contiguous memory to user space and lets the user space application mmap() this memory and pass a pointer using the USERPTR interface for V4L2 zero copy operation. With this approach we support zero copy capture, hardware scaling and various forms of hardware encoding and decoding. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
Magnus Damm <damm@igel.co.jp> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Paul Mundt <lethal@linux-sh.org> Acked-by:
Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by:
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Johannes Weiner authored
Analoguous to follow_phys(), add a helper that looks up the PFN at a user virtual address in an IO mapping or a raw PFN mapping. Signed-off-by:
Magnus Damm <magnus.damm@gmail.com> Cc: Hans Verkuil <hverkuil@xs4all.nl> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by:
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Johannes Weiner authored
Signed-off-by:
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Johannes Weiner authored
A generic readonly page table lookup helper to map an address space and an address from it to a pte. Signed-off-by:
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Cyrill Gorcunov authored
The caller of setup_per_zone_inactive_ratio is an __init function. There is no need to keep the callee after it completed as well. Also fix a comment. Acked-by:
Cyrill Gorcunov <gorcunov@openvz.org> Reviewed-by:
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Cyrill Gorcunov authored
int_sqrt() returns 0 if its argument is zero so call it if only needed. Signed-off-by:
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Wu Fengguang authored
This effectively lifts the unit of updates to nr_inactive_* and pgdeactivate from PAGEVEC_SIZE=14 to SWAP_CLUSTER_MAX=32, or MAX_ORDER_NR_PAGES=1024 for reclaim_zone(). Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by:
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Wu Fengguang authored
The lru->nr_saved_scan's are not meaningful counters for even kernel developers. They typically are smaller than 32 and are always 0 for large lists. So remove them from /proc/zoneinfo. Hopefully this interface change won't break too many scripts. /proc/zoneinfo is too unstructured to be script friendly, and I wonder the affected scripts - if there are any - are still bleeding since the not long ago commit "vmscan: split LRU lists into anon & file sets", which also touched the "scanned" line :) If we are to re-export accumulated vmscan counts in the future, they can go to new lines in /proc/zoneinfo instead of the current form, or to /sys/devices/system/node/node0/meminfo? Signed-off-by:
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