From: Michal Hocko <mhocko@suse.cz>
Date: Tue, 26 Jul 2011 23:08:24 +0000 (-0700)
Subject: memcg: change memcg_oom_mutex to spinlock
X-Git-Tag: v3.1-rc1~209
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1af8efe965676ab30d6c8a5b1fccc9229f339a3b;p=pandora-kernel.git

memcg: change memcg_oom_mutex to spinlock

memcg_oom_mutex is used to protect memcg OOM path and eventfd interface
for oom_control.  None of the critical sections which it protects sleep
(eventfd_signal works from atomic context and the rest are simple linked
list resp.  oom_lock atomic operations).

Mutex is also too heavyweight for those code paths because it triggers a
lot of scheduling.  It also makes makes convoying effects more visible
when we have a big number of oom killing because we take the lock
mutliple times during mem_cgroup_handle_oom so we have multiple places
where many processes can sleep.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

Reading git-diff-tree failed