[008/145] memcg: fix oom killing a child process in an other cgroup

From: Greg KH
Date: Fri Mar 12 2010 - 19:58:12 EST


2.6.32-stable review patch. If anyone has any objections, please let me know.

----------------
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

commit 5a2d41961dd6815b874b5c0afec0ac96cd90eea4 upstream.

Presently the oom-killer is memcg aware and it finds the worst process
from processes under memcg(s) in oom. Then, it kills victim's child
first.

It may kill a child in another cgroup and may not be any help for
recovery. And it will break the assumption users have.

This patch fixes it.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
mm/oom_kill.c | 2 ++
1 file changed, 2 insertions(+)

--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -426,6 +426,8 @@ static int oom_kill_process(struct task_
list_for_each_entry(c, &p->children, sibling) {
if (c->mm == p->mm)
continue;
+ if (mem && !task_in_mem_cgroup(c, mem))
+ continue;
if (!oom_kill_task(c))
return 0;
}


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