1. 10 Aug, 2010 40 commits
    • 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
    • Mel Gorman's avatar
      vmscan: tracing: add trace events for LRU page isolation · a8a94d15
      Mel Gorman authored
      Add an event for when pages are isolated en-masse from the LRU lists.
      This event augments the information available on LRU traffic and can be
      used to evaluate lumpy reclaim.
      
      [akpm@linux-foundation.org: coding-style fixes]
      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>
      a8a94d15
    • Mel Gorman's avatar
      vmscan: tracing: add trace events for kswapd wakeup, sleeping and direct reclaim · 33906bc5
      Mel Gorman authored
      Add two trace events for kswapd waking up and going asleep for the
      purposes of tracking kswapd activity and two trace events for direct
      reclaim beginning and ending.  The information can be used to work out how
      much time a process or the system is spending on the reclamation of pages
      and in the case of direct reclaim, how many pages were reclaimed for that
      process.  High frequency triggering of these events could point to memory
      pressure problems.
      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>
      33906bc5
    • KOSAKI Motohiro's avatar
      vmscan: recalculate lru_pages on each priority · c6a8a8c5
      KOSAKI Motohiro authored
      shrink_zones() need relatively long time and lru_pages can change
      dramatically during shrink_zones().  So lru_pages should be recalculated
      for each priority.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c6a8a8c5
    • KOSAKI Motohiro's avatar
      vmscan: zone_reclaim don't call disable_swap_token() · b00d3ea7
      KOSAKI Motohiro authored
      Swap token don't works when zone reclaim is enabled since it was born.
      Because __zone_reclaim() always call disable_swap_token() unconditionally.
      
      This kill swap token feature completely.  As far as I know, nobody want to
      that.  Remove it.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b00d3ea7
    • Jan Kara's avatar
      mm: implement writeback livelock avoidance using page tagging · f446daae
      Jan Kara authored
      We try to avoid livelocks of writeback when some steadily creates dirty
      pages in a mapping we are writing out.  For memory-cleaning writeback,
      using nr_to_write works reasonably well but we cannot really use it for
      data integrity writeback.  This patch tries to solve the problem.
      
      The idea is simple: Tag all pages that should be written back with a
      special tag (TOWRITE) in the radix tree.  This can be done rather quickly
      and thus livelocks should not happen in practice.  Then we start doing the
      hard work of locking pages and sending them to disk only for those pages
      that have TOWRITE tag set.
      
      Note: Adding new radix tree tag grows radix tree node from 288 to 296
      bytes for 32-bit archs and from 552 to 560 bytes for 64-bit archs.
      However, the number of slab/slub items per page remains the same (13 and 7
      respectively).
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Theodore Ts'o <tytso@mit.edu>
      Cc: Jens Axboe <axboe@kernel.dk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f446daae
    • Jan Kara's avatar
      radix-tree: omplement function radix_tree_range_tag_if_tagged · ebf8aa44
      Jan Kara authored
      Implement function for setting one tag if another tag is set for each item
      in given range.
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Theodore Ts'o <tytso@mit.edu>
      Cc: Jens Axboe <axboe@kernel.dk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ebf8aa44
    • Andrea Arcangeli's avatar
      rmap: add anon_vma bug checks · 44ab57a0
      Andrea Arcangeli authored
      Verify the refcounting doesn't go wrong, and resurrect the check in
      __page_check_anon_rmap as in old anon-vma code.
      Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Signed-off-by: default avatarRik 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>
      44ab57a0
    • Andrea Arcangeli's avatar
      rmap: resurrect page_address_in_vma anon_vma check · 21d0d443
      Andrea Arcangeli authored
      With root anon-vma it's trivial to keep doing the usual check as in
      old-anon-vma code.
      Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Signed-off-by: default avatarRik 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>
      21d0d443
    • Andrea Arcangeli's avatar
      rmap: always use anon_vma root pointer · 288468c3
      Andrea Arcangeli authored
      Always use anon_vma->root pointer instead of anon_vma_chain.prev.
      
      Also optimize the map-paths, if a mapping is already established no need
      to overwrite it with root anon-vma list, we can keep the more finegrined
      anon-vma and skip the overwrite: see the PageAnon check in !exclusive
      case.  This is also the optimization that hidden the ksm bug as this tends
      to make ksm_might_need_to_copy skip the copy, but only the proper fix to
      ksm_might_need_to_copy guarantees not triggering the ksm bug unless ksm is
      in use.  this is an optimization only...
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Signed-off-by: default avatarRik van Riel <riel@redhat.com>
      [kamezawa.hiroyu@jp.fujitsu.com: fix false positive BUG_ON in __page_set_anon_rmap]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      288468c3
    • Andrea Arcangeli's avatar
      ksm: fix ksm swapin time optimization · ba6f0ff3
      Andrea Arcangeli authored
      The new anon-vma code, was suboptimal and it lead to erratic invocation of
      ksm_does_need_to_copy.  That leads to host hangs or guest vnc lockup, or
      weird behavior.  It's unclear why ksm_does_need_to_copy is unstable but
      the point is that when KSM is not in use, ksm_does_need_to_copy must never
      run or we bounce pages for no good reason.  I suspect the same hangs will
      happen with KVM swaps.  But this at least fixes the regression in the
      new-anon-vma code and it only let KSM bugs triggers when KSM is in use.
      
      The code in do_swap_page likely doesn't cope well with a not-swapcache,
      especially the memcg code.
      Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Signed-off-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Izik Eidus <ieidus@yahoo.com>
      Cc: Avi Kivity <avi@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ba6f0ff3
    • Andrea Arcangeli's avatar
      rmap: always add new vmas at the end · 26ba0cb6
      Andrea Arcangeli authored
      Make sure to always add new VMAs at the end of the list.  This is
      important so rmap_walk does not miss a VMA that was created during the
      rmap_walk.
      
      The old code got this right most of the time due to luck, but was buggy
      when anon_vma_prepare reused a mergeable anon_vma.
      Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Signed-off-by: default avatarRik 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>
      26ba0cb6
    • Andrea Arcangeli's avatar
      mmap: remove unnecessary lock from __vma_link · 5e549e98
      Andrea Arcangeli authored
      There's no anon-vma related mangling happening inside __vma_link anymore
      so no need of anon_vma locking there.
      Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
      Signed-off-by: default avatarRik 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>
      5e549e98
    • Shaohua Li's avatar
      shmem: reduce pagefault lock contention · ff36b801
      Shaohua Li authored
      I'm running a shmem pagefault test case (see attached file) under a 64 CPU
      system.  Profile shows shmem_inode_info->lock is heavily contented and
      100% CPUs time are trying to get the lock.  In the pagefault (no swap)
      case, shmem_getpage gets the lock twice, the last one is avoidable if we
      prealloc a page so we could reduce one time of locking.  This is what
      below patch does.
      
      The result of the test case:
      2.6.35-rc3: ~20s
      2.6.35-rc3 + patch: ~12s
      so this is 40% improvement.
      
      One might argue if we could have better locking for shmem.  But even shmem
      is lockless, the pagefault will soon have pagecache lock heavily contented
      because shmem must add new page to pagecache.  So before we have better
      locking for pagecache, improving shmem locking doesn't have too much
      improvement.  I did a similar pagefault test against a ramfs file, the
      test result is ~10.5s.
      
      [akpm@linux-foundation.org: fix comment, clean up code layout, elimintate code duplication]
      Signed-off-by: default avatarShaohua Li <shaohua.li@intel.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: "Zhang, Yanmin" <yanmin.zhang@intel.com>
      Cc: Tim Chen <tim.c.chen@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ff36b801
    • Tim Chen's avatar
      tmpfs: make tmpfs scalable with percpu_counter for used blocks · 7e496299
      Tim Chen authored
      The current implementation of tmpfs is not scalable.  We found that
      stat_lock is contended by multiple threads when we need to get a new page,
      leading to useless spinning inside this spin lock.
      
      This patch makes use of the percpu_counter library to maintain local count
      of used blocks to speed up getting and returning of pages.  So the
      acquisition of stat_lock is unnecessary for getting and returning blocks,
      improving the performance of tmpfs on system with large number of cpus.
      On a 4 socket 32 core NHM-EX system, we saw improvement of 270%.
      
      The implementation below has a slight chance of race between threads
      causing a slight overshoot of the maximum configured blocks.  However, any
      overshoot is small, and is bounded by the number of cpus.  This happens
      when the number of used blocks is slightly below the maximum configured
      blocks when a thread checks the used block count, and another thread
      allocates the last block before the current thread does.  This should not
      be a problem for tmpfs, as the overshoot is most likely to be a few blocks
      and bounded.  If a strict limit is really desired, then configured the max
      blocks to be the limit less the number of cpus in system.
      Signed-off-by: default avatarTim Chen <tim.c.chen@linux.intel.com>
      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>
      7e496299