From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 9ABA68D003B for ; Mon, 11 Apr 2011 20:35:21 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 1535F3EE0B6 for ; Tue, 12 Apr 2011 09:35:18 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id E691145DE60 for ; Tue, 12 Apr 2011 09:35:17 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id C616A45DE56 for ; Tue, 12 Apr 2011 09:35:17 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id B813A1DB804F for ; Tue, 12 Apr 2011 09:35:17 +0900 (JST) Received: from ml13.s.css.fujitsu.com (ml13.s.css.fujitsu.com [10.240.81.133]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 82D521DB8047 for ; Tue, 12 Apr 2011 09:35:17 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH 2/4] remove boost_dying_task_prio() In-Reply-To: <20110411145832.ae133cf8.akpm@linux-foundation.org> References: <20110411143215.0074.A69D9226@jp.fujitsu.com> <20110411145832.ae133cf8.akpm@linux-foundation.org> Message-Id: <20110412093503.43EF.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 12 Apr 2011 09:35:16 +0900 (JST) Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: kosaki.motohiro@jp.fujitsu.com, Andrey Vagin , Minchan Kim , KAMEZAWA Hiroyuki , "Luis Claudio R. Goncalves" , LKML , linux-mm , David Rientjes , Oleg Nesterov , Linus Torvalds Hi > On Mon, 11 Apr 2011 14:31:18 +0900 (JST) > KOSAKI Motohiro wrote: > > > This is a almost revert commit 93b43fa (oom: give the dying > > task a higher priority). > > > > The commit dramatically improve oom killer logic when fork-bomb > > occur. But, I've found it has nasty corner case. Now cpu cgroup > > has strange default RT runtime. It's 0! That said, if a process > > under cpu cgroup promote RT scheduling class, the process never > > run at all. > > hm. How did that happen? I thought that sched_setscheduler() modifies > only a single thread, and that thread is in the process of exiting? If admin insert !RT process into a cpu cgroup of setting rtruntime=0, usually it run perfectly because !RT task isn't affected from rtruntime knob, but If it promote RT task, by explicit setscheduler() syscall or OOM, the task can't run at all. In short, now oom killer don't work at all if admin are using cpu cgroup and don't touch rtruntime knob. -- 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