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 ESMTP id 428998D0040 for ; Tue, 12 Apr 2011 06:55:19 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp (unknown [10.0.50.73]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id F091E3EE081 for ; Tue, 12 Apr 2011 19:55:15 +0900 (JST) Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id D5AE445DE99 for ; Tue, 12 Apr 2011 19:55:15 +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 BA91045DE92 for ; Tue, 12 Apr 2011 19:55:15 +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 A9D1BE08006 for ; Tue, 12 Apr 2011 19:55:15 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.240.81.147]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 753F0E08004 for ; Tue, 12 Apr 2011 19:55:15 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH 1/4] vmscan: all_unreclaimable() use zone->all_unreclaimable as a name In-Reply-To: <20110411182606.016f9486.akpm@linux-foundation.org> References: <20110412100417.43F2.A69D9226@jp.fujitsu.com> <20110411182606.016f9486.akpm@linux-foundation.org> Message-Id: <20110412195513.B533.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 12 Apr 2011 19:55:14 +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 > > The above says "Eventually, oom-killer never works". Is this no enough? > > The above says > > 1) current logic have a race > > 2) x86 increase a chance of the race by dma zone > > 3) if race is happen, oom killer don't work > > And the system hangs up, so it's a local DoS and I guess we should > backport the fix into -stable. I added this: > > : This resulted in the kernel hanging up when executing a loop of the form > : > : 1. fork > : 2. mmap > : 3. touch memory > : 4. read memory > : 5. munmmap > : > : as described in > : http://www.gossamer-threads.com/lists/linux/kernel/1348725#1348725 > > And the problems which the other patches in this series address are > pretty deadly as well. Should we backport everything? patch [1/4] and [2/4] should be backported because they are regression fix. But [3/4] and [4/4] are on borderline to me. they improve a recovery time from oom. some times it is very important, some times not. And it is not regression fix. Our oom-killer is very weak from forkbomb attack since very old days. 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org