1. 10 Aug, 2010 40 commits
    • Michael Cree's avatar
      alpha: implement HW performance events on the EV67 and later CPUs · 979f8671
      Michael Cree authored
      This implements hardware performance events for the EV67 and later CPUs
      within the Linux performance events subsystem.  Only using the performance
      monitoring unit in HP/Compaq's so called "Aggregrate mode" is supported.
      
      The code has been implemented in a manner that makes extension to other
      older Alpha CPUs relatively straightforward should some mug wish to
      indulge themselves.
      Signed-off-by: default avatarMichael Cree <mcree@orcon.net.nz>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Jay Estabrook <jay.estabrook@hp.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      979f8671
    • Michael Cree's avatar
      alpha: add wrperfmon.h header file to aid use of wrperfmon PALcall · 92484f10
      Michael Cree authored
      Signed-off-by: default avatarMichael Cree <mcree@orcon.net.nz>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Jay Estabrook <jay.estabrook@hp.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      92484f10
    • Michael Cree's avatar
      alpha: add performance monitor interrupt counter · 65d92064
      Michael Cree authored
      The following patches implement hardware performance events for the Alpha
      EV67 and later CPUs.  I have had this running on a Compaq XP1000 (EV67,
      single CPU) for a few days now.  Pretty cool -- discovered that the glibc
      exp2() library routine uses on average 985 cycles to execute 777 CPU
      instructions whereas Compaq's CPML library version of exp2() uses on
      average 32 cycles to execute 47 CPU instructions to achieve the same
      thing!
      
      This patch:
      
      Add performance monitor interrupt counternd and export the count to user
      space via /proc/interrupts.
      Signed-off-by: default avatarMichael Cree <mcree@orcon.net.nz>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Jay Estabrook <jay.estabrook@hp.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      65d92064
    • Jan Kara's avatar
      mm: avoid resetting wb_start after each writeback round · 7624ee72
      Jan Kara authored
      WB_SYNC_NONE writeback is done in rounds of 1024 pages so that we don't
      write out some huge inode for too long while starving writeout of other
      inodes.  To avoid livelocks, we record time we started writeback in
      wbc->wb_start and do not write out inodes which were dirtied after this
      time.  But currently, writeback_inodes_wb() resets wb_start each time it
      is called thus effectively invalidating this logic and making any
      WB_SYNC_NONE writeback prone to livelocks.
      
      This patch makes sure wb_start is set only once when we start writeback.
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Reviewed-by: default avatarWu Fengguang <fengguang.wu@intel.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Acked-by: default avatarJens Axboe <jaxboe@fusionio.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7624ee72
    • Lai Jiangshan's avatar
      ksm: cleanup for mm_slots_hash · d9f8984c
      Lai Jiangshan authored
      Use compile-allocated memory instead of dynamic allocated memory for
      mm_slots_hash.
      
      Use hash_ptr() instead divisions for bucket calculation.
      Signed-off-by: default avatarLai Jiangshan <laijs@cn.fujitsu.com>
      Signed-off-by: default avatarIzik Eidus <ieidus@redhat.com>
      Cc: Avi Kivity <avi@redhat.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d9f8984c
    • Wu Fengguang's avatar
      vmscan: raise the bar to PAGEOUT_IO_SYNC stalls · e31f3698
      Wu Fengguang authored
      Fix "system goes unresponsive under memory pressure and lots of
      dirty/writeback pages" bug.
      
      	http://lkml.org/lkml/2010/4/4/86
      
      In the above thread, Andreas Mohr described that
      
      	Invoking any command locked up for minutes (note that I'm
      	talking about attempted additional I/O to the _other_,
      	_unaffected_ main system HDD - such as loading some shell
      	binaries -, NOT the external SSD18M!!).
      
      This happens when the two conditions are both meet:
      - under memory pressure
      - writing heavily to a slow device
      
      OOM also happens in Andreas' system.  The OOM trace shows that 3 processes
      are stuck in wait_on_page_writeback() in the direct reclaim path.  One in
      do_fork() and the other two in unix_stream_sendmsg().  They are blocked on
      this condition:
      
      	(sc->order && priority < DEF_PRIORITY - 2)
      
      which was introduced in commit 78dc583d (vmscan: low order lumpy reclaim
      also should use PAGEOUT_IO_SYNC) one year ago.  That condition may be too
      permissive.  In Andreas' case, 512MB/1024 = 512KB.  If the direct reclaim
      for the order-1 fork() allocation runs into a range of 512KB
      hard-to-reclaim LRU pages, it will be stalled.
      
      It's a severe problem in three ways.
      
      Firstly, it can easily happen in daily desktop usage.  vmscan priority can
      easily go below (DEF_PRIORITY - 2) on _local_ memory pressure.  Even if
      the system has 50% globally reclaimable pages, it still has good
      opportunity to have 0.1% sized hard-to-reclaim ranges.  For example, a
      simple dd can easily create a big range (up to 20%) of dirty pages in the
      LRU lists.  And order-1 to order-3 allocations are more than common with
      SLUB.  Try "grep -v '1 :' /proc/slabinfo" to get the list of high order
      slab caches.  For example, the order-1 radix_tree_node slab cache may
      stall applications at swap-in time; the order-3 inode cache on most
      filesystems may stall applications when trying to read some file; the
      order-2 proc_inode_cache may stall applications when trying to open a
      /proc file.
      
      Secondly, once triggered, it will stall unrelated processes (not doing IO
      at all) in the system.  This "one slow USB device stalls the whole system"
      avalanching effect is very bad.
      
      Thirdly, once stalled, the stall time could be intolerable long for the
      users.  When there are 20MB queued writeback pages and USB 1.1 is writing
      them in 1MB/s, wait_on_page_writeback() will stuck for up to 20 seconds.
      Not to mention it may be called multiple times.
      
      So raise the bar to only enable PAGEOUT_IO_SYNC when priority goes below
      DEF_PRIORITY/3, or 6.25% LRU size.  As the default dirty throttle ratio is
      20%, it will hardly be triggered by pure dirty pages.  We'd better treat
      PAGEOUT_IO_SYNC as some last resort workaround -- its stall time is so
      uncomfortably long (easily goes beyond 1s).
      
      The bar is only raised for (order < PAGE_ALLOC_COSTLY_ORDER) allocations,
      which are easy to satisfy in 1TB memory boxes.  So, although 6.25% of
      memory could be an awful lot of pages to scan on a system with 1TB of
      memory, it won't really have to busy scan that much.
      
      Andreas tested an older version of this patch and reported that it mostly
      fixed his problem.  Mel Gorman helped improve it and KOSAKI Motohiro will
      fix it further in the next patch.
      Reported-by: default avatarAndreas Mohr <andi@lisas.de>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e31f3698
    • Kulikov Vasiliy's avatar
      mm/vmalloc.c: check kmalloc() return value · 51980ac9
      Kulikov Vasiliy authored
      kmalloc() may fail, if so return -ENOMEM.
      Signed-off-by: default avatarKulikov Vasiliy <segooon@gmail.com>
      Acked-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      51980ac9
    • KOSAKI Motohiro's avatar
      memcg: add mm_vmscan_memcg_isolate tracepoint · cc8e970c
      KOSAKI Motohiro authored
      Memcg also need to trace page isolation information as global reclaim.
      This patch does it.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
      Acked-by: default avatarBalbir Singh <balbir@linux.vnet.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cc8e970c
    • KOSAKI Motohiro's avatar
      vmscan: convert mm_vmscan_lru_isolate to DEFINE_EVENT · e17613c3
      KOSAKI Motohiro authored
      Mel Gorman recently added some vmscan tracepoints.  Unfortunately they are
      covered only global reclaim.  But we want to trace memcg reclaim too.
      
      Thus, this patch convert them to DEFINE_TRACE macro.  it help to reuse
      tracepoint definition for other similar usage (i.e.  memcg).  This patch
      have no functionally change.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarBalbir Singh <balbir@linux.vnet.ibm.com>
      Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e17613c3
    • KOSAKI Motohiro's avatar
      memcg, vmscan: add memcg reclaim tracepoint · bdce6d9e
      KOSAKI Motohiro authored
      Memcg also need to trace reclaim progress as direct reclaim.  This patch
      add it.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
      Acked-by: default avatarBalbir Singh <balbir@linux.vnet.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bdce6d9e
    • KOSAKI Motohiro's avatar
      vmscan: convert direct reclaim tracepoint to DEFINE_TRACE · cf4dcc3e
      KOSAKI Motohiro authored
      Mel Gorman recently added some vmscan tracepoints.  Unfortunately they are
      covered only global reclaim.  But we want to trace memcg reclaim too.
      
      Thus, this patch convert them to DEFINE_TRACE macro.  it help to reuse
      tracepoint definition for other similar usage (i.e.  memcg).  This patch
      have no functionally change.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
      Acked-by: default avatarBalbir Singh <balbir@linux.vnet.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cf4dcc3e
    • KOSAKI Motohiro's avatar
      vmscan: shrink_slab() requires the number of lru_pages, not the page order · 4dc4b3d9
      KOSAKI Motohiro authored
      Presently shrink_slab() has the following scanning equation.
      
                                  lru_scanned        max_pass
        basic_scan_objects = 4 x -------------  x -----------------------------
                                  lru_pages        shrinker->seeks (default:2)
      
        scan_objects = min(basic_scan_objects, max_pass * 2)
      
      If we pass very small value as lru_pages instead real number of lru pages,
      shrink_slab() drop much objects rather than necessary.  And now,
      __zone_reclaim() pass 'order' as lru_pages by mistake.  That produces a
      bad result.
      
      For example, if we receive very low memory pressure (scan = 32, order =
      0), shrink_slab() via zone_reclaim() always drop _all_ icache/dcache
      objects.  (see above equation, very small lru_pages make very big
      scan_objects result).
      
      This patch fixes it.
      
      [akpm@linux-foundation.org: fix layout, typos]
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Acked-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4dc4b3d9
    • Jeremy Fitzhardinge's avatar
      mmu-notifiers: remove mmu notifier calls in apply_to_page_range() · 57250a5b
      Jeremy Fitzhardinge authored
      It is not appropriate for apply_to_page_range() to directly call any mmu
      notifiers, because it is a general purpose function whose effect depends
      on what context it is called in and what the callback function does.
      
      In particular, if it is being used as part of an mmu notifier
      implementation, the recursive calls can be particularly problematic.
      
      It is up to apply_to_page_range's caller to do any notifier calls if
      necessary.  It does not affect any in-tree users because they all operate
      on init_mm, and mmu notifiers only pertain to usermode mappings.
      
      [stefano.stabellini@eu.citrix.com: remove unused local `start']
      Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
      Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
      Cc: Avi Kivity <avi@qumranet.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      57250a5b
    • KOSAKI Motohiro's avatar
      vmscan: protect reading of reclaim_stat with lru_lock · 58c37f6e
      KOSAKI Motohiro authored
      Rik van Riel pointed out reading reclaim_stat should be protected
      lru_lock, otherwise vmscan might sweep 2x much pages.
      
      This fault was introduced by
      
        commit 4f98a2fe
        Author: Rik van Riel <riel@redhat.com>
        Date:   Sat Oct 18 20:26:32 2008 -0700
      
          vmscan: split LRU lists into anon & file sets
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      58c37f6e
    • KOSAKI Motohiro's avatar
      vmscan: avoid subtraction of unsigned types · 15748048
      KOSAKI Motohiro authored
      'slab_reclaimable' and 'nr_pages' are unsigned.  Subtraction is unsafe
      because negative results would be misinterpreted.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      15748048
    • KOSAKI Motohiro's avatar
      drivers/base/node.c: reduce stack usage of node_read_meminfo() · 7ee92255
      KOSAKI Motohiro authored
      	drivers/base/node.c: In function 'node_read_meminfo':
      	drivers/base/node.c:139: warning: the frame size of 848 bytes is
      	larger than 512 bytes
      
      Fix it by splitting the sprintf() into three parts.  It has no functional
      change.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Greg KH <greg@kroah.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7ee92255
    • Andrea Arcangeli's avatar
      mm: set VM_FAULT_WRITE in do_swap_page() · 9a5b489b
      Andrea Arcangeli authored
      Set the flag if do_swap_page is decowing the page the same way do_wp_page
      would too.
      Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Hugh Dickins <hughd@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9a5b489b
    • Rik van Riel's avatar
      rmap: add exclusive page to private anon_vma on swapin · ad8c2ee8
      Rik van Riel authored
      On swapin it is fairly common for a page to be owned exclusively by one
      process.  In that case we want to add the page to the anon_vma of that
      process's VMA, instead of to the root anon_vma.
      
      This will reduce the amount of rmap searching that the swapout code needs
      to do.
      Signed-off-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ad8c2ee8
    • David Rientjes's avatar
      oom: deprecate oom_adj tunable · 51b1bd2a
      David Rientjes authored
      /proc/pid/oom_adj is now deprecated so that that it may eventually be
      removed.  The target date for removal is August 2012.
      
      A warning will be printed to the kernel log if a task attempts to use this
      interface.  Future warning will be suppressed until the kernel is rebooted
      to prevent spamming the kernel log.
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Balbir Singh <balbir@in.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      51b1bd2a
    • David Rientjes's avatar
      oom: badness heuristic rewrite · a63d83f4
      David Rientjes authored
      This a complete rewrite of the oom killer's badness() heuristic which is
      used to determine which task to kill in oom conditions.  The goal is to
      make it as simple and predictable as possible so the results are better
      understood and we end up killing the task which will lead to the most
      memory freeing while still respecting the fine-tuning from userspace.
      
      Instead of basing the heuristic on mm->total_vm for each task, the task's
      rss and swap space is used instead.  This is a better indication of the
      amount of memory that will be freeable if the oom killed task is chosen
      and subsequently exits.  This helps specifically in cases where KDE or
      GNOME is chosen for oom kill on desktop systems instead of a memory
      hogging task.
      
      The baseline for the heuristic is a proportion of memory that each task is
      currently using in memory plus swap compared to the amount of "allowable"
      memory.  "Allowable," in this sense, means the system-wide resources for
      unconstrained oom conditions, the set of mempolicy nodes, the mems
      attached to current's cpuset, or a memory controller's limit.  The
      proportion is given on a scale of 0 (never kill) to 1000 (always kill),
      roughly meaning that if a task has a badness() score of 500 that the task
      consumes approximately 50% of allowable memory resident in RAM or in swap
      space.
      
      The proportion is always relative to the amount of "allowable" memory and
      not the total amount of RAM systemwide so that mempolicies and cpusets may
      operate in isolation; they shall not need to know the true size of the
      machine on which they are running if they are bound to a specific set of
      nodes or mems, respectively.
      
      Root tasks are given 3% extra memory just like __vm_enough_memory()
      provides in LSMs.  In the event of two tasks consuming similar amounts of
      memory, it is generally better to save root's task.
      
      Because of the change in the badness() heuristic's baseline, it is also
      necessary to introduce a new user interface to tune it.  It's not possible
      to redefine the meaning of /proc/pid/oom_adj with a new scale since the
      ABI cannot be changed for backward compatability.  Instead, a new tunable,
      /proc/pid/oom_score_adj, is added that ranges from -1000 to +1000.  It may
      be used to polarize the heuristic such that certain tasks are never
      considered for oom kill while others may always be considered.  The value
      is added directly into the badness() score so a value of -500, for
      example, means to discount 50% of its memory consumption in comparison to
      other tasks either on the system, bound to the mempolicy, in the cpuset,
      or sharing the same memory controller.
      
      /proc/pid/oom_adj is changed so that its meaning is rescaled into the
      units used by /proc/pid/oom_score_adj, and vice versa.  Changing one of
      these per-task tunables will rescale the value of the other to an
      equivalent meaning.  Although /proc/pid/oom_adj was originally defined as
      a bitshift on the badness score, it now shares the same linear growth as
      /proc/pid/oom_score_adj but with different granularity.  This is required
      so the ABI is not broken with userspace applications and allows oom_adj to
      be deprecated for future removal.
      Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Balbir Singh <balbir@in.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a63d83f4
    • Andrew Morton's avatar
      oom: move badness() declaration into oom.h · 74bcbf40
      Andrew Morton authored
      Cc: Minchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      74bcbf40
    • KOSAKI Motohiro's avatar
      oom: multi threaded process coredump don't make deadlock · cef1d352
      KOSAKI Motohiro authored
      Oleg pointed out current PF_EXITING check is wrong. Because PF_EXITING
      is per-thread flag, not per-process flag. He said,
      
         Two threads, group-leader L and its sub-thread T. T dumps the code.
         In this case both threads have ->mm != NULL, L has PF_EXITING.
      
         The first problem is, select_bad_process() always return -1 in this
         case (even if the caller is T, this doesn't matter).
      
         The second problem is that we should add TIF_MEMDIE to T, not L.
      
      I think we can remove this dubious PF_EXITING check. but as first step,
      This patch add the protection of multi threaded issue.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Minchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cef1d352
    • Luis Claudio R. Goncalves's avatar
      oom: give the dying task a higher priority · 93b43fa5
      Luis Claudio R. Goncalves authored
      In a system under heavy load it was observed that even after the
      oom-killer selects a task to die, the task may take a long time to die.
      
      Right after sending a SIGKILL to the task selected by the oom-killer this
      task has its priority increased so that it can exit() soon, freeing
      memory.  That is accomplished by:
      
              /*
               * We give our sacrificial lamb high priority and access to
               * all the memory it needs. That way it should be able to
               * exit() and clear out its resources quickly...
               */
       	p->rt.time_slice = HZ;
       	set_tsk_thread_flag(p, TIF_MEMDIE);
      
      It sounds plausible giving the dying task an even higher priority to be
      sure it will be scheduled sooner and free the desired memory.  It was
      suggested on LKML using SCHED_FIFO:1, the lowest RT priority so that this
      task won't interfere with any running RT task.
      
      If the dying task is already an RT task, leave it untouched.  Another good
      suggestion, implemented here, was to avoid boosting the dying task
      priority in case of mem_cgroup OOM.
      Signed-off-by: default avatarLuis Claudio R. Goncalves <lclaudio@uudg.org>
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      93b43fa5
    • KOSAKI Motohiro's avatar
      oom: remove child->mm check from oom_kill_process() · 19b4586c
      KOSAKI Motohiro authored
      The current "child->mm == p->mm" check prevents selection of vfork()ed
      task.  But we don't have any reason to don't consider vfork().
      
      Removed.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Minchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      19b4586c
    • KOSAKI Motohiro's avatar
      oom: cleanup has_intersects_mems_allowed() · df1090a8
      KOSAKI Motohiro authored
      presently has_intersects_mems_allowed() has own thread iterate logic, but
      it should use while_each_thread().
      
      It slightly improve the code readability.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      df1090a8
    • KOSAKI Motohiro's avatar
      oom: move OOM_DISABLE check from oom_kill_task to out_of_memory() · a96cfd6e
      KOSAKI Motohiro authored
      Presently if oom_kill_allocating_task is enabled and current have
      OOM_DISABLED, following printk in oom_kill_process is called twice.
      
          pr_err("%s: Kill process %d (%s) score %lu or sacrifice child\n",
                  message, task_pid_nr(p), p->comm, points);
      
      So, OOM_DISABLE check should be more early.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Minchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a96cfd6e
    • KOSAKI Motohiro's avatar
      oom: kill duplicate OOM_DISABLE check · 113e27f3
      KOSAKI Motohiro authored
      select_bad_process() and badness() have the same OOM_DISABLE check.  This
      patch kills one.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      113e27f3
    • KOSAKI Motohiro's avatar
      oom: /proc/<pid>/oom_score treat kernel thread honestly · 26ebc984
      KOSAKI Motohiro authored
      If a kernel thread is using use_mm(), badness() returns a positive value.
      This is not a big issue because caller take care of it correctly.  But
      there is one exception, /proc/<pid>/oom_score calls badness() directly and
      doesn't care that the task is a regular process.
      
      Another example, /proc/1/oom_score return !0 value.  But it's unkillable.
      This incorrectness makes administration a little confusing.
      
      This patch fixes it.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Minchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      26ebc984
    • KOSAKI Motohiro's avatar
      oom: oom_kill_process() needs to check that p is unkillable · f88ccad5
      KOSAKI Motohiro authored
      When oom_kill_allocating_task is enabled, an argument task of
      oom_kill_process is not selected by select_bad_process(), It's just
      out_of_memory() caller task.  It mean the task can be unkillable.  check
      it first.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f88ccad5
    • KOSAKI Motohiro's avatar
      oom: make oom_unkillable_task() helper function · ab290adb
      KOSAKI Motohiro authored
      Presently we have the same task check in two places. Unify it.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ab290adb
    • KOSAKI Motohiro's avatar
      oom: oom_kill_process() doesn't select kthread child · 2c5ea53c
      KOSAKI Motohiro authored
      Presently select_bad_process() has a PF_KTHREAD check, but
      oom_kill_process doesn't.  It mean oom_kill_process() may choose wrong
      task, especially, when the child are using use_mm().
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2c5ea53c
    • KOSAKI Motohiro's avatar
      oom: don't try to kill oom_unkillable child · 7c59aec8
      KOSAKI Motohiro authored
      Presently, badness() doesn't care about either CPUSET nor mempolicy.  Then
      if the victim child process have disjoint nodemask, OOM Killer might kill
      innocent process.
      
      This patch fixes it.
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Cc: Minchan Kim <minchan.kim@gmail.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7c59aec8
    • Mel Gorman's avatar
      vmscan: update isolated page counters outside of main path in shrink_inactive_list() · 1489fa14
      Mel Gorman authored
      When shrink_inactive_list() isolates pages, it updates a number of
      counters using temporary variables to gather them.  These consume stack
      and it's in the main path that calls ->writepage().  This patch moves the
      accounting updates outside of the main path to reduce stack usage.
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Reviewed-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Michael Rubin <mrubin@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1489fa14
    • Mel Gorman's avatar
      vmscan: set up pagevec as late as possible in shrink_page_list() · abe4c3b5
      Mel Gorman authored
      shrink_page_list() sets up a pagevec to release pages as according as they
      are free.  It uses significant amounts of stack on the pagevec.  This
      patch adds pages to be freed via pagevec to a linked list which is then
      freed en-masse at the end.  This avoids using stack in the main path that
      potentially calls writepage().
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Reviewed-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Michael Rubin <mrubin@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      abe4c3b5
    • Mel Gorman's avatar
      vmscan: set up pagevec as late as possible in shrink_inactive_list() · 66635629
      Mel Gorman authored
      shrink_inactive_list() sets up a pagevec to release unfreeable pages.  It
      uses significant amounts of stack doing this.  This patch splits
      shrink_inactive_list() to take the stack usage out of the main path so
      that callers to writepage() do not contain an unused pagevec on the stack.
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Reviewed-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Michael Rubin <mrubin@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      66635629
    • Mel Gorman's avatar
      vmscan: remove unnecessary temporary vars in do_try_to_free_pages · d4debc66
      Mel Gorman authored
      Remove temporary variable that is only used once and does not help clarify
      code.
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Reviewed-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Michael Rubin <mrubin@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d4debc66
    • KOSAKI Motohiro's avatar
      vmscan: simplify shrink_inactive_list() · e247dbce
      KOSAKI Motohiro authored
      Now, max_scan of shrink_inactive_list() is always passed less than
      SWAP_CLUSTER_MAX.  then, we can remove scanning pages loop in it.  This
      patch also help stack diet.
      
      detail
       - remove "while (nr_scanned < max_scan)" loop
       - remove nr_freed (now, we use nr_reclaimed directly)
       - remove nr_scan (now, we use nr_scanned directly)
       - rename max_scan to nr_to_scan
       - pass nr_to_scan into isolate_pages() directly instead
         using SWAP_CLUSTER_MAX
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Reviewed-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Reviewed-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Michael Rubin <mrubin@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e247dbce
    • KOSAKI Motohiro's avatar
      vmscan: kill prev_priority completely · 25edde03
      KOSAKI Motohiro authored
      Since 2.6.28 zone->prev_priority is unused. Then it can be removed
      safely. It reduce stack usage slightly.
      
      Now I have to say that I'm sorry. 2 years ago, I thought prev_priority
      can be integrate again, it's useful. but four (or more) times trying
      haven't got good performance number. Thus I give up such approach.
      
      The rest of this changelog is notes on prev_priority and why it existed in
      the first place and why it might be not necessary any more. This information
      is based heavily on discussions between Andrew Morton, Rik van Riel and
      Kosaki Motohiro who is heavily quotes from.
      
      Historically prev_priority was important because it determined when the VM
      would start unmapping PTE pages. i.e. there are no balances of note within
      the VM, Anon vs File and Mapped vs Unmapped. Without prev_priority, there
      is a potential risk of unnecessarily increasing minor faults as a large
      amount of read activity of use-once pages could push mapped pages to the
      end of the LRU and get unmapped.
      
      There is no proof this is still a problem but currently it is not considered
      to be. Active files are not deactivated if the active file list is smaller
      than the inactive list reducing the liklihood that file-mapped pages are
      being pushed off the LRU and referenced executable pages are kept on the
      active list to avoid them getting pushed out by read activity.
      
      Even if it is a problem, prev_priority prev_priority wouldn't works
      nowadays. First of all, current vmscan still a lot of UP centric code. it
      expose some weakness on some dozens CPUs machine. I think we need more and
      more improvement.
      
      The problem is, current vmscan mix up per-system-pressure, per-zone-pressure
      and per-task-pressure a bit. example, prev_priority try to boost priority to
      other concurrent priority. but if the another task have mempolicy restriction,
      it is unnecessary, but also makes wrong big latency and exceeding reclaim.
      per-task based priority + prev_priority adjustment make the emulation of
      per-system pressure. but it have two issue 1) too rough and brutal emulation
      2) we need per-zone pressure, not per-system.
      
      Another example, currently DEF_PRIORITY is 12. it mean the lru rotate about
      2 cycle (1/4096 + 1/2048 + 1/1024 + .. + 1) before invoking OOM-Killer.
      but if 10,0000 thrreads enter DEF_PRIORITY reclaim at the same time, the
      system have higher memory pressure than priority==0 (1/4096*10,000 > 2).
      prev_priority can't solve such multithreads workload issue. In other word,
      prev_priority concept assume the sysmtem don't have lots threads."
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Reviewed-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Reviewed-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Michael Rubin <mrubin@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      25edde03
    • Mel Gorman's avatar
      vmscan: tracing: add a postprocessing script for reclaim-related ftrace events · b898cc70
      Mel Gorman authored
      Add a simple post-processing script for the reclaim-related trace events.
      It can be used to give an indication of how much traffic there is on the
      LRU lists and how severe latencies due to reclaim are.  Example output
      looks like the following
      
      Reclaim latencies expressed as order-latency_in_ms
      uname-3942             9-200.179000000004 9-98.7900000000373 9-99.8330000001006
      kswapd0-311            0-662.097999999998 0-2.79700000002049 \
      	0-149.100000000035 0-3295.73600000003 0-9806.31799999997 0-35528.833 \
      	0-10043.197 0-129740.979 0-3.50500000000466 0-3.54899999999907 \
      	0-9297.78999999992 0-3.48499999998603 0-3596.97999999998 0-3.92799999995623 \
      	0-3.35000000009313 0-16729.017 0-3.57799999997951 0-47435.0630000001 \
      	0-3.7819999998901 0-5864.06999999995 0-18635.334 0-10541.289 9-186011.565 \
      	9-3680.86300000001 9-1379.06499999994 9-958571.115 9-66215.474 \
      	9-6721.14699999988 9-1962.15299999993 9-10948061.125 9-2267.83199999994 \
      	9-47120.9029999999 9-427653.886 9-2.6359999999404 9-632.148999999976 \
      	9-476.753000000026 9-495.577000000048 9-8.45900000003166 9-6.6820000000298 \
      	9-1.30500000016764 9-251.746000000043 9-383.905000000028 9-80.1419999999925 \
      	9-281.160000000149 9-14.8780000000261 9-381.45299999998 9-512.07799999998 \
      	9-49.5519999999087 9-167.439000000013 9-183.820999999996 9-239.527999999933 \
      	9-19.9479999998584 9-148.747999999905 9-164.583000000101 9-16.9480000000913 \
      	9-192.376000000164 9-64.1010000000242 9-1.40800000005402 9-3.60800000000745 \
      	9-17.1359999999404 9-4.69500000006519 9-2.06400000001304 9-1582488.554 \
      	9-6244.19499999983 9-348153.812 9-2.0999999998603 9-0.987999999895692 \
      	0-32218.473 0-1.6140000000596 0-1.28100000019185 0-1.41300000017509 \
      	0-1.32299999985844 0-602.584000000032 0-1.34400000004098 0-1.6929999999702 \
      	1-22101.8190000001 9-174876.724 9-16.2420000000857 9-175.165999999736 \
      	9-15.8589999997057 9-0.604999999981374 9-3061.09000000032 9-479.277000000235 \
      	9-1.54499999992549 9-771.985000000335 9-4.88700000010431 9-15.0649999999441 \
      	9-0.879999999888241 9-252.01500000013 9-1381.03600000031 9-545.689999999944 \
      	9-3438.0129999998 9-3343.70099999988
      bench-stresshig-3942   9-7063.33900000004 9-129960.482 9-2062.27500000002 \
      	9-3845.59399999992 9-171.82799999998 9-16493.821 9-7615.23900000006 \
      	9-10217.848 9-983.138000000035 9-2698.39999999991 9-4016.1540000001 \
      	9-5522.37700000009 9-21630.429 \
      	9-15061.048 9-10327.953 9-542.69700000016 9-317.652000000002 \
      	9-8554.71699999995 9-1786.61599999992 9-1899.31499999994 9-2093.41899999999 \
      	9-4992.62400000007 9-942.648999999976 9-1923.98300000001 9-3.7980000001844 \
      	9-5.99899999983609 9-0.912000000011176 9-1603.67700000014 9-1.98300000000745 \
      	9-3.96500000008382 9-0.902999999932945 9-2802.72199999983 9-1078.24799999991 \
      	9-2155.82900000014 9-10.058999999892 9-1984.723 9-1687.97999999998 \
      	9-1136.05300000007 9-3183.61699999985 9-458.731000000145 9-6.48600000003353 \
      	9-1013.25200000009 9-8415.22799999989 9-10065.584 9-2076.79600000009 \
      	9-3792.65699999989 9-71.2010000001173 9-2560.96999999997 9-2260.68400000012 \
      	9-2862.65799999982 9-1255.81500000018 9-15.7440000001807 9-4.33499999996275 \
      	9-1446.63800000004 9-238.635000000009 9-60.1790000000037 9-4.38800000003539 \
      	9-639.567000000039 9-306.698000000091 9-31.4070000001229 9-74.997999999905 \
      	9-632.725999999791 9-1625.93200000003 9-931.266000000061 9-98.7749999999069 \
      	9-984.606999999844 9-225.638999999966 9-421.316000000108 9-653.744999999879 \
      	9-572.804000000004 9-769.158999999985 9-603.918000000063 9-4.28499999991618 \
      	9-626.21399999992 9-1721.25 9-0.854999999981374 9-572.39599999995 \
      	9-681.881999999983 9-1345.12599999993 9-363.666999999899 9-3823.31099999999 \
      	9-2991.28200000012 9-4.27099999994971 9-309.76500000013 9-3068.35700000008 \
      	9-788.25 9-3515.73999999999 9-2065.96100000013 9-286.719999999972 \
      	9-316.076000000117 9-344.151000000071 9-2.51000000000931 9-306.688000000082 \
      	9-1515.00099999993 9-336.528999999864 9-793.491999999853 9-457.348999999929 \
      	9-13620.155 9-119.933999999892 9-35.0670000000391 9-918.266999999993 \
      	9-828.569000000134 9-4863.81099999999 9-105.222000000067 9-894.23900000006 \
      	9-110.964999999851 9-0.662999999942258 9-12753.3150000002 9-12.6129999998957 \
      	9-13368.0899999999 9-12.4199999999255 9-1.00300000002608 9-1.41100000008009 \
      	9-10300.5290000001 9-16.502000000095 9-30.7949999999255 9-6283.0140000002 \
      	9-4320.53799999994 9-6826.27300000004 9-3.07299999985844 9-1497.26799999992 \
      	9-13.4040000000969 9-3.12999999988824 9-3.86100000003353 9-11.3539999998175 \
      	9-0.10799999977462 9-21.780999999959 9-209.695999999996 9-299.647000000114 \
      	9-6.01699999999255 9-20.8349999999627 9-22.5470000000205 9-5470.16800000006 \
      	9-7.60499999998137 9-0.821000000229105 9-1.56600000010803 9-14.1669999998994 \
      	9-0.209000000031665 9-1.82300000009127 9-1.70000000018626 9-19.9429999999702 \
      	9-124.266999999993 9-0.0389999998733401 9-6.71400000015274 9-16.7710000001825 \
      	9-31.0409999999683 9-0.516999999992549 9-115.888000000035 9-5.19900000002235 \
      	9-222.389999999898 9-11.2739999999758 9-80.9050000000279 9-8.14500000001863 \
      	9-4.44599999999627 9-0.218999999808148 9-0.715000000083819 9-0.233000000007451
      \
      	9-48.2630000000354 9-248.560999999987 9-374.96800000011 9-644.179000000004 \
      	9-0.835999999893829 9-79.0060000000522 9-128.447999999858 9-0.692000000039116 \
      	9-5.26500000013039 9-128.449000000022 9-2.04799999995157 9-12.0990000001621 \
      	9-8.39899999997579 9-10.3860000001732 9-11.9310000000987 9-53.4450000000652 \
      	9-0.46999999997206 9-2.96299999998882 9-17.9699999999721 9-0.776000000070781 \
      	9-25.2919999998994 9-33.1110000000335 9-0.434000000124797 9-0.641000000061467 \
      	9-0.505000000121072 9-1.12800000002608 9-149.222000000067 9-1.17599999997765 \
      	9-3247.33100000001 9-10.7439999999478 9-153.523000000045 9-1.38300000014715 \
      	9-794.762000000104 9-3.36199999996461 9-128.765999999829 9-181.543999999994 \
      	9-78149.8229999999 9-176.496999999974 9-89.9940000001807 9-9.12700000009499 \
      	9-250.827000000048 9-0.224999999860302 9-0.388999999966472 9-1.16700000036508 \
      	9-32.1740000001155 9-12.6800000001676 9-0.0720000001601875 9-0.274999999906868
      \
      	9-0.724000000394881 9-266.866000000387 9-45.5709999999963 9-4.54399999976158 \
      	9-8.27199999988079 9-4.38099999958649 9-0.512000000104308 9-0.0640000002458692
      \
      	9-5.20000000018626 9-0.0839999997988343 9-12.816000000108 9-0.503000000026077 \
      	9-0.507999999914318 9-6.23999999975786 9-3.35100000025705 9-18.8530000001192 \
      	9-25.2220000000671 9-68.2309999996796 9-98.9939999999478 9-0.441000000108033 \
      	9-4.24599999981001 9-261.702000000048 9-3.01599999982864 9-0.0749999997206032 \
      	9-0.0370000000111759 9-4.375 9-3.21800000034273 9-11.3960000001825 \
      	9-0.0540000000037253 9-0.286000000312924 9-0.865999999921769 \
      	9-0.294999999925494 9-6.45999999996275 9-4.31099999975413 9-128.248999999836 \
      	9-0.282999999821186 9-102.155000000261 9-0.0860000001266599 \
      	9-0.0540000000037253 9-0.935000000055879 9-0.0670000002719462 \
      	9-5.8640000000596 9-19.9860000000335 9-4.18699999991804 9-0.566000000108033 \
      	9-2.55099999997765 9-0.702000000048429 9-131.653999999631 9-0.638999999966472 \
      	9-14.3229999998584 9-183.398000000045 9-178.095999999903 9-3.22899999981746 \
      	9-7.31399999978021 9-22.2400000002235 9-11.7979999999516 9-108.10599999968 \
      	9-99.0159999998286 9-102.640999999829 9-38.414000000339
      Process                  Direct     Wokeup      Pages      Pages    Pages
      details                   Rclms     Kswapd    Scanned    Sync-IO ASync-IO
      cc1-30800                     0          1          0          0        0      wakeup-0=1
      cc1-24260                     0          1          0          0        0      wakeup-0=1
      cc1-24152                     0         12          0          0        0      wakeup-0=12
      cc1-8139                      0          1          0          0        0      wakeup-0=1
      cc1-4390                      0          1          0          0        0      wakeup-0=1
      cc1-4648                      0          7          0          0        0      wakeup-0=7
      cc1-4552                      0          3          0          0        0      wakeup-0=3
      dd-4550                       0         31          0          0        0      wakeup-0=31
      date-4898                     0          1          0          0        0      wakeup-0=1
      cc1-6549                      0          7          0          0        0      wakeup-0=7
      as-22202                      0         17          0          0        0      wakeup-0=17
      cc1-6495                      0          9          0          0        0      wakeup-0=9
      cc1-8299                      0          1          0          0        0      wakeup-0=1
      cc1-6009                      0          1          0          0        0      wakeup-0=1
      cc1-2574                      0          2          0          0        0      wakeup-0=2
      cc1-30568                     0          1          0          0        0      wakeup-0=1
      cc1-2679                      0          6          0          0        0      wakeup-0=6
      sh-13747                      0         12          0          0        0      wakeup-0=12
      cc1-22193                     0         18          0          0        0      wakeup-0=18
      cc1-30725                     0          2          0          0        0      wakeup-0=2
      as-4392                       0          2          0          0        0      wakeup-0=2
      cc1-28180                     0         14          0          0        0      wakeup-0=14
      cc1-13697                     0          2          0          0        0      wakeup-0=2
      cc1-22207                     0          8          0          0        0      wakeup-0=8
      cc1-15270                     0        179          0          0        0      wakeup-0=179
      cc1-22011                     0         82          0          0        0      wakeup-0=82
      cp-14682                      0          1          0          0        0      wakeup-0=1
      as-11926                      0          2          0          0        0      wakeup-0=2
      cc1-6016                      0          5          0          0        0      wakeup-0=5
      make-18554                    0         13          0          0        0      wakeup-0=13
      cc1-8292                      0         12          0          0        0      wakeup-0=12
      make-24381                    0          1          0          0        0      wakeup-1=1
      date-18681                    0         33          0          0        0      wakeup-0=33
      cc1-32276                     0          1          0          0        0      wakeup-0=1
      timestamp-outpu-2809          0        253          0          0        0      wakeup-0=240 wakeup-1=13
      date-18624                    0          7          0          0        0      wakeup-0=7
      cc1-30960                     0          9          0          0        0      wakeup-0=9
      cc1-4014                      0          1          0          0        0      wakeup-0=1
      cc1-30706                     0         22          0          0        0      wakeup-0=22
      uname-3942                    4          1        306          0       17      direct-9=4       wakeup-9=1
      cc1-28207                     0          1          0          0        0      wakeup-0=1
      cc1-30563                     0          9          0          0        0      wakeup-0=9
      cc1-22214                     0         10          0          0        0      wakeup-0=10
      cc1-28221                     0         11          0          0        0      wakeup-0=11
      cc1-28123                     0          6          0          0        0      wakeup-0=6
      kswapd0-311                   0          7     357302          0    34233      wakeup-0=7
      cc1-5988                      0          7          0          0        0      wakeup-0=7
      as-30734                      0        161          0          0        0      wakeup-0=161
      cc1-22004                     0         45          0          0        0      wakeup-0=45
      date-4590                     0          4          0          0        0      wakeup-0=4
      cc1-15279                     0        213          0          0        0      wakeup-0=213
      date-30735                    0          1          0          0        0      wakeup-0=1
      cc1-30583                     0          4          0          0        0      wakeup-0=4
      cc1-32324                     0          2          0          0        0      wakeup-0=2
      cc1-23933                     0          3          0          0        0      wakeup-0=3
      cc1-22001                     0         36          0          0        0      wakeup-0=36
      bench-stresshig-3942        287        287      80186       6295    12196      direct-9=287       wakeup-9=287
      cc1-28170                     0          7          0          0        0      wakeup-0=7
      date-7932                     0         92          0          0        0      wakeup-0=92
      cc1-22222                     0          6          0          0        0      wakeup-0=6
      cc1-32334                     0         16          0          0        0      wakeup-0=16
      cc1-2690                      0          6          0          0        0      wakeup-0=6
      cc1-30733                     0          9          0          0        0      wakeup-0=9
      cc1-32298                     0          2          0          0        0      wakeup-0=2
      cc1-13743                     0         18          0          0        0      wakeup-0=18
      cc1-22186                     0          4          0          0        0      wakeup-0=4
      cc1-28214                     0         11          0          0        0      wakeup-0=11
      cc1-13735                     0          1          0          0        0      wakeup-0=1
      updatedb-8173                 0         18          0          0        0      wakeup-0=18
      cc1-13750                     0          3          0          0        0      wakeup-0=3
      cat-2808                      0          2          0          0        0      wakeup-0=2
      cc1-15277                     0        169          0          0        0      wakeup-0=169
      date-18317                    0          1          0          0        0      wakeup-0=1
      cc1-15274                     0        197          0          0        0      wakeup-0=197
      cc1-30732                     0          1          0          0        0      wakeup-0=1
      
      Kswapd                   Kswapd      Order      Pages      Pages    Pages
      Instance                Wakeups  Re-wakeup    Scanned    Sync-IO ASync-IO
      kswapd0-311                  91         24     357302          0    34233      wake-0=31 wake-1=1 wake-9=59       rewake-0=10 rewake-1=1 rewake-9=13
      
      Summary
      Direct reclaims:     		291
      Direct reclaim pages scanned:	437794
      Direct reclaim write sync I/O:	6295
      Direct reclaim write async I/O:	46446
      Wake kswapd requests:		2152
      Time stalled direct reclaim: 	519.163009000002 ms
      
      Kswapd wakeups:			91
      Kswapd pages scanned:		357302
      Kswapd reclaim write sync I/O:	0
      Kswapd reclaim write async I/O:	34233
      Time kswapd awake:		5282.749757 ms
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Acked-by: default avatarLarry Woodman <lwoodman@redhat.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Michael Rubin <mrubin@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b898cc70
    • Mel Gorman's avatar
      vmscan: tracing: add trace event when a page is written · 755f0225
      Mel Gorman authored
      Add a trace event for when page reclaim queues a page for IO and records
      whether it is synchronous or asynchronous.  Excessive synchronous IO for a
      process can result in noticeable stalls during direct reclaim.  Excessive
      IO from page reclaim may indicate that the system is seriously under
      provisioned for the amount of dirty pages that exist.
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Acked-by: default avatarLarry Woodman <lwoodman@redhat.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Michael Rubin <mrubin@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      755f0225