From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx207.postini.com [74.125.245.207]) by kanga.kvack.org (Postfix) with SMTP id 98D5B6B029D for ; Tue, 13 Dec 2011 20:07:17 -0500 (EST) Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 8D79B3EE0BD for ; Wed, 14 Dec 2011 10:07:15 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 718F645DF59 for ; Wed, 14 Dec 2011 10:07:15 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 3C1EA45DF58 for ; Wed, 14 Dec 2011 10:07:15 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 2374C1DB803F for ; Wed, 14 Dec 2011 10:07:15 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.240.81.145]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id C0808E08001 for ; Wed, 14 Dec 2011 10:07:14 +0900 (JST) Date: Wed, 14 Dec 2011 10:06:00 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [patch] oom, memcg: fix exclusion of memcg threads after they have detached their mm Message-Id: <20111214100600.6f5975ba.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Johannes Weiner , Michal Hocko , Balbir Singh , cgroups@vger.kernel.org, linux-mm@kvack.org On Tue, 13 Dec 2011 16:59:32 -0800 (PST) David Rientjes wrote: > The oom killer relies on logic that identifies threads that have already > been oom killed when scanning the tasklist and, if found, deferring until > such threads have exited. This is done by checking for any candidate > threads that have the TIF_MEMDIE bit set. > > For memcg ooms, candidate threads are first found by calling > task_in_mem_cgroup() since the oom killer should not defer if there's an > oom killed thread in another memcg. > > Unfortunately, task_in_mem_cgroup() excludes threads if they have > detached their mm in the process of exiting so TIF_MEMDIE is never > detected for such conditions. This is different for global, mempolicy, > and cpuset oom conditions where a detached mm is only excluded after > checking for TIF_MEMDIE and deferring, if necessary, in > select_bad_process(). > > The fix is to return true if a task has a detached mm but is still in the > memcg that is currently oom. This will allow the oom killer to > appropriately defer rather than kill unnecessarily or, in the worst case, > panic the machine if nothing else is available to kill. > > Signed-off-by: David Rientjes > --- > mm/memcontrol.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1110,7 +1110,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) > > p = find_lock_task_mm(task); > if (!p) > - return 0; > + return mem_cgroup_from_task(task) == memcg; > curr = try_get_mem_cgroup_from_mm(p->mm); > task_unlock(p); > if (!curr) Acked-by: KAMEZAWA Hiroyuki -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org