From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id E14278D0039 for ; Wed, 9 Mar 2011 00:59:02 -0500 (EST) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id D8CA33EE0CB for ; Wed, 9 Mar 2011 14:58:59 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id C010E45DE51 for ; Wed, 9 Mar 2011 14:58:59 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 9C6DD45DE4D for ; Wed, 9 Mar 2011 14:58:59 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 90F7A1DB803E for ; Wed, 9 Mar 2011 14:58:59 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.240.81.147]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 5B6861DB802F for ; Wed, 9 Mar 2011 14:58:59 +0900 (JST) Date: Wed, 9 Mar 2011 14:52:39 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH] mm: check zone->all_unreclaimable in all_unreclaimable() Message-Id: <20110309145239.ba31b415.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <4D767D43.5020802@gmail.com> References: <20110307135831.9e0d7eaa.akpm@linux-foundation.org> <20110308094438.1ba05ed2.kamezawa.hiroyu@jp.fujitsu.com> <20110308120615.7EB9.A69D9226@jp.fujitsu.com> <4D767D43.5020802@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: avagin@gmail.com Cc: KOSAKI Motohiro , Andrew Morton , Minchan Kim , Andrey Vagin , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, 08 Mar 2011 22:02:27 +0300 "avagin@gmail.com" wrote: > On 03/08/2011 06:06 AM, KOSAKI Motohiro wrote: > >>>> Hmm.. Although it solves the problem, I think it's not a good idea that > >>>> depends on false alram and give up the retry. > >>> > >>> Any alternative proposals? We should get the livelock fixed if possible.. > >> > >> I agree with Minchan and can't think this is a real fix.... > >> Andrey, I'm now trying your fix and it seems your fix for oom-killer, > >> 'skip-zombie-process' works enough good for my environ. > >> > >> What is your enviroment ? number of cpus ? architecture ? size of memory ? > > > > me too. 'skip-zombie-process V1' work fine. and I didn't seen this patch > > improve oom situation. > > > > And, The test program is purely fork bomb. Our oom-killer is not silver > > bullet for fork bomb from very long time ago. That said, oom-killer send > > SIGKILL and start to kill the victim process. But, it doesn't prevent > > to be created new memory hogging tasks. Therefore we have no gurantee > > to win process exiting and creating race. > > I think a live-lock is a bug, even if it's provoked by fork bomds. > I tried to write fork-bomb-detector in oom-kill layer but I think it should be co-operative with do_fork(), now. IOW, some fork() should return -ENOMEM under OOM condition. I'd like to try some but if you have some idea, please do. > And now I want say some words about zone->all_unreclaimable. I think > this flag is "conservative". It is set when situation is bad and it's > unset when situation get better. If we have a small number of > reclaimable pages, the situation is still bad. What do you mean, when > say that kernel is alive? If we have one reclaimable page, is the kernel > alive? Yes, it can work, it will generate many page faults and do > something, but anyone say that it is more dead than alive. > > Try to look at it from my point of view. The patch will be correct and > the kernel will be more alive. > > Excuse me, If I'm mistaken... > Mayne something more casual interface than oom-kill should be provided. I wonder I can add memory-reclaim-priority to memory cgroup and allow control of page fault latency for applicaton... Maybe "soft_limit" for memcg, it's implemented now, works to some extent. Thanks, -Kame -- 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