From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 4163B6B037C for ; Sun, 22 Aug 2010 05:49:10 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp ([10.0.50.73]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o7M9n6ZN026283 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Sun, 22 Aug 2010 18:49:06 +0900 Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 269D945DE4F for ; Sun, 22 Aug 2010 18:49:06 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id EF05F45DE4E for ; Sun, 22 Aug 2010 18:49:05 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id D493C1DB8038 for ; Sun, 22 Aug 2010 18:49:05 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 8CD811DB8037 for ; Sun, 22 Aug 2010 18:49:05 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [patch 2/3 v3] oom: avoid killing a task if a thread sharing its mm cannot be killed In-Reply-To: References: Message-Id: <20100822184526.600F.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Sun, 22 Aug 2010 18:49:04 +0900 (JST) Sender: owner-linux-mm@kvack.org To: David Rientjes Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , KAMEZAWA Hiroyuki , Rik van Riel , linux-mm@kvack.org List-ID: > > The oom killer's goal is to kill a memory-hogging task so that it may > exit, free its memory, and allow the current context to allocate the > memory that triggered it in the first place. Thus, killing a task is > pointless if other threads sharing its mm cannot be killed because of its > /proc/pid/oom_adj or /proc/pid/oom_score_adj value. > > This patch checks whether any other thread sharing p->mm has an > oom_score_adj of OOM_SCORE_ADJ_MIN. If so, the thread cannot be killed > and oom_badness(p) returns 0, meaning it's unkillable. > > Signed-off-by: David Rientjes > --- > mm/oom_kill.c | 9 +++++---- > 1 files changed, 5 insertions(+), 4 deletions(-) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -162,10 +162,11 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, > return 0; > > /* > - * Shortcut check for OOM_SCORE_ADJ_MIN so the entire heuristic doesn't > - * need to be executed for something that cannot be killed. > + * Shortcut check for a thread sharing p->mm that is OOM_SCORE_ADJ_MIN > + * so the entire heuristic doesn't need to be executed for something > + * that cannot be killed. > */ > - if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { > + if (atomic_read(&p->mm->oom_disable_count)) { > task_unlock(p); > return 0; > } > @@ -675,7 +676,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, > read_lock(&tasklist_lock); > if (sysctl_oom_kill_allocating_task && > !oom_unkillable_task(current, NULL, nodemask) && > - (current->signal->oom_adj != OOM_DISABLE)) { > + current->mm && !atomic_read(¤t->mm->oom_disable_count)) { > /* > * oom_kill_process() needs tasklist_lock held. If it returns > * non-zero, current could not be killed so we must fallback to This seems significantly cleaner than previous. Of cource, even though I need to review [1/3] carefully. Unfortunatelly I'm very busy in this week, then my responce might late a while. but it's not mean silinetly nak. Thanks. -- 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/ . Don't email: email@kvack.org