]> git.baikalelectronics.ru Git - kernel.git/commit
oom: remove oom_disable_count
authorDavid Rientjes <rientjes@google.com>
Tue, 1 Nov 2011 00:07:15 +0000 (17:07 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 1 Nov 2011 00:30:45 +0000 (17:30 -0700)
commita068066cdb62479a4027352072520bf012d78990
tree13ffde591a5bcefba39cb6393f09b27f1ebc1a30
parentfd3fea0b62e8c61dee1c042e5a0d6644a838e527
oom: remove oom_disable_count

This removes mm->oom_disable_count entirely since it's unnecessary and
currently buggy.  The counter was intended to be per-process but it's
currently decremented in the exit path for each thread that exits, causing
it to underflow.

The count was originally intended to prevent oom killing threads that
share memory with threads that cannot be killed since it doesn't lead to
future memory freeing.  The counter could be fixed to represent all
threads sharing the same mm, but it's better to remove the count since:

 - it is possible that the OOM_DISABLE thread sharing memory with the
   victim is waiting on that thread to exit and will actually cause
   future memory freeing, and

 - there is no guarantee that a thread is disabled from oom killing just
   because another thread sharing its mm is oom disabled.

Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ying Han <yinghan@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/exec.c
fs/proc/base.c
include/linux/mm_types.h
kernel/exit.c
kernel/fork.c
mm/oom_kill.c