From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Date: Wed, 10 Mar 2010 23:22:32 +0000 (-0800)
Subject: memcg: handle panic_on_oom=always case
X-Git-Tag: v2.6.34-rc2~160
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=daaf1e68874c078a15ae6ae827751839c4d81739;p=pandora-kernel.git

memcg: handle panic_on_oom=always case

Presently, if panic_on_oom=2, the whole system panics even if the oom
happend in some special situation (as cpuset, mempolicy....).  Then,
panic_on_oom=2 means painc_on_oom_always.

Now, memcg doesn't check panic_on_oom flag. This patch adds a check.

BTW, how it's useful ?

kdump+panic_on_oom=2 is the last tool to investigate what happens in
oom-ed system.  When a task is killed, the sysytem recovers and there will
be few hint to know what happnes.  In mission critical system, oom should
never happen.  Then, panic_on_oom=2+kdump is useful to avoid next OOM by
knowing precise information via snapshot.

TODO:
 - For memcg, it's for isolate system's memory usage, oom-notiifer and
   freeze_at_oom (or rest_at_oom) should be implemented. Then, management
   daemon can do similar jobs (as kdump) or taking snapshot per cgroup.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

Reading git-diff-tree failed