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 984E56B01AD for ; Mon, 29 Mar 2010 08:09:11 -0400 (EDT) Date: Mon, 29 Mar 2010 20:09:04 +0800 From: anfei Subject: Re: [PATCH] oom killer: break from infinite loop Message-ID: <20100329120904.GB11838@desktop> References: <1269447905-5939-1-git-send-email-anfei.zhou@gmail.com> <20100326150805.f5853d1c.akpm@linux-foundation.org> <20100326223356.GA20833@redhat.com> <20100328145528.GA14622@desktop> <20100328162821.GA16765@redhat.com> <20100329113113.GA11838@desktop> <20100329114630.GA19277@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100329114630.GA19277@redhat.com> Sender: owner-linux-mm@kvack.org To: Oleg Nesterov Cc: Andrew Morton , rientjes@google.com, kosaki.motohiro@jp.fujitsu.com, nishimura@mxp.nes.nec.co.jp, kamezawa.hiroyu@jp.fujitsu.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Mon, Mar 29, 2010 at 01:46:30PM +0200, Oleg Nesterov wrote: > On 03/29, anfei wrote: > > > > On Sun, Mar 28, 2010 at 06:28:21PM +0200, Oleg Nesterov wrote: > > > On 03/28, anfei wrote: > > > > > > > > Assume thread A and B are in the same group. If A runs into the oom, > > > > and selects B as the victim, B won't exit because at least in exit_mm(), > > > > it can not get the mm->mmap_sem semaphore which A has already got. > > > > > > I see. But still I can't understand. To me, the problem is not that > > > B can't exit, the problem is that A doesn't know it should exit. All > > > > If B can exit, its memory will be freed, > > Which memory? I thought, we are talking about the memory used by ->mm ? > There is also a little kernel struct related to the task can be freed, but I think you are correct, the memory used by ->mm takes more effect, and it won't be freed even B exits. So I agree you on: " the problem is not that B can't exit, the problem is that A doesn't know it should exit. All threads should exit and free ->mm. Even if B could exit, this is not enough. And, to some extent, it doesn't matter if it holds mmap_sem or not. " Thanks, Anfei. > Oleg. > -- 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