From: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Date: Wed, 16 Dec 2009 00:47:12 +0000 (-0800)
Subject: memcg: avoid oom-killing innocent task in case of use_hierarchy
X-Git-Tag: v2.6.33-rc1~71^2~88
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d31f56dbf8bafaacb0c617f9a6f137498d5c7aed;p=pandora-kernel.git

memcg: avoid oom-killing innocent task in case of use_hierarchy

task_in_mem_cgroup(), which is called by select_bad_process() to check
whether a task can be a candidate for being oom-killed from memcg's limit,
checks "curr->use_hierarchy"("curr" is the mem_cgroup the task belongs
to).

But this check return true(it's false positive) when:

	<some path>/aa		use_hierarchy == 0	<- hitting limit
	  <some path>/aa/00	use_hierarchy == 1	<- the task belongs to

This leads to killing an innocent task in aa/00.  This patch is a fix for
this bug.  And this patch also fixes the arg for
mem_cgroup_print_oom_info().  We should print information of mem_cgroup
which the task being killed, not current, belongs to.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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