releases/2.6.19.2/fix-oom-killing-of-swapoff.patch

   1 From stable-bounces@linux.kernel.org  Fri Jan  5 16:57:46 2007
   2 Message-Id: <200701060037.l060bUhd013413@shell0.pdx.osdl.net>
   3 To: torvalds@osdl.org
   4 From: akpm@osdl.org
   5 Date: Fri, 05 Jan 2007 16:37:03 -0800
   6 Cc: akpm@osdl.org, hugh@veritas.com, stable@kernel.org
   7 Subject: fix OOM killing of swapoff
   8
   9 From: Hugh Dickins <hugh@veritas.com>
  10
  11 These days, if you swapoff when there isn't enough memory, OOM killer gives
  12 "BUG: scheduling while atomic" and the machine hangs: badness() needs to do
  13 its PF_SWAPOFF return after the task_unlock (tasklist_lock is also held
  14 here, so p isn't going to be freed: PF_SWAPOFF might get turned off at any
  15 moment, but that doesn't really matter).
  16
  17 Signed-off-by: Hugh Dickins <hugh@veritas.com>
  18 Cc: <stable@kernel.org>
  19 Signed-off-by: Andrew Morton <akpm@osdl.org>
  20 Signed-off-by: Chris Wright <chrisw@sous-sol.org>
  21 ---
  22
  23  mm/oom_kill.c |   12 ++++++------
  24  1 file changed, 6 insertions(+), 6 deletions(-)
  25
  26 --- linux-2.6.19.1.orig/mm/oom_kill.c
  27 +++ linux-2.6.19.1/mm/oom_kill.c
  28 @@ -61,12 +61,6 @@ unsigned long badness(struct task_struct
  29         }
  30
  31         /*
  32 -        * swapoff can easily use up all memory, so kill those first.
  33 -        */
  34 -       if (p->flags & PF_SWAPOFF)
  35 -               return ULONG_MAX;
  36 -
  37 -       /*
  38          * The memory size of the process is the basis for the badness.
  39          */
  40         points = mm->total_vm;
  41 @@ -77,6 +71,12 @@ unsigned long badness(struct task_struct
  42         task_unlock(p);
  43
  44         /*
  45 +        * swapoff can easily use up all memory, so kill those first.
  46 +        */
  47 +       if (p->flags & PF_SWAPOFF)
  48 +               return ULONG_MAX;
  49 +
  50 +       /*
  51          * Processes which fork a lot of child processes are likely
  52          * a good choice. We add half the vmsize of the children if they
  53          * have an own mm. This prevents forking servers to flood the