From: Johannes Weiner <hannes@cmpxchg.org>
Date: Wed, 24 Jun 2015 23:57:04 +0000 (-0700)
Subject: mm: oom_kill: remove unnecessary locking in oom_enable()
X-Git-Tag: v4.9.8~4063^2~38
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3f5ab8cfbf15e8e02838ffc3549191351305df0e;p=platform%2Fkernel%2Flinux-rpi3.git

mm: oom_kill: remove unnecessary locking in oom_enable()

Setting oom_killer_disabled to false is atomic, there is no need for
further synchronization with ongoing allocations trying to OOM-kill.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 2b665da..73763e4 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -488,9 +488,7 @@ bool oom_killer_disable(void)
  */
 void oom_killer_enable(void)
 {
-	down_write(&oom_sem);
 	oom_killer_disabled = false;
-	up_write(&oom_sem);
 }
 
 #define K(x) ((x) << (PAGE_SHIFT-10))