Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757065Ab1DLKzW (ORCPT ); Tue, 12 Apr 2011 06:55:22 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:60351 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753303Ab1DLKzU (ORCPT ); Tue, 12 Apr 2011 06:55:20 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Andrew Morton Subject: Re: [PATCH 1/4] vmscan: all_unreclaimable() use zone->all_unreclaimable as a name 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 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 X-Mailer: Becky! ver. 2.56.05 [ja] Date: Tue, 12 Apr 2011 19:55:14 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1315 Lines: 39 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/