From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with ESMTP id 988606B007B for ; Tue, 16 Feb 2010 21:28:10 -0500 (EST) Received: from spaceape24.eur.corp.google.com (spaceape24.eur.corp.google.com [172.28.16.76]) by smtp-out.google.com with ESMTP id o1H2SB9Z012793 for ; Tue, 16 Feb 2010 18:28:12 -0800 Received: from pxi35 (pxi35.prod.google.com [10.243.27.35]) by spaceape24.eur.corp.google.com with ESMTP id o1H2S9pV026777 for ; Tue, 16 Feb 2010 18:28:10 -0800 Received: by pxi35 with SMTP id 35so1515868pxi.16 for ; Tue, 16 Feb 2010 18:28:09 -0800 (PST) Date: Tue, 16 Feb 2010 18:28:05 -0800 (PST) From: David Rientjes Subject: Re: [patch -mm 4/9 v2] oom: remove compulsory panic_on_oom mode In-Reply-To: <20100217111319.d342f10e.kamezawa.hiroyu@jp.fujitsu.com> Message-ID: References: <20100216090005.f362f869.kamezawa.hiroyu@jp.fujitsu.com> <20100216092311.86bceb0c.kamezawa.hiroyu@jp.fujitsu.com> <20100217084239.265c65ea.kamezawa.hiroyu@jp.fujitsu.com> <20100217090124.398769d5.kamezawa.hiroyu@jp.fujitsu.com> <20100217094137.a0d26fbb.kamezawa.hiroyu@jp.fujitsu.com> <20100217111319.d342f10e.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Andrew Morton , Rik van Riel , Nick Piggin , Andrea Arcangeli , Balbir Singh , Lubos Lunak , KOSAKI Motohiro , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Wed, 17 Feb 2010, KAMEZAWA Hiroyuki wrote: > > What do you think about making pagefaults use out_of_memory() directly and > > respecting the sysctl_panic_on_oom settings? > > > > I don't think this patch is good. Because several memcg can > cause oom at the same time independently, system-wide oom locking is > unsuitable. BTW, what I doubt is much more fundamental thing. > We want to lock all populated zones with ZONE_OOM_LOCKED to avoid needlessly killing more than one task regardless of how many memcgs are oom. > What I doubt at most is "why VM_FAULT_OOM is necessary ? or why we have > to call oom_killer when page fault returns it". > Is there someone who returns VM_FAULT_OOM without calling page allocator > and oom-killer helps something in such situation ? > Before we invoked the oom killer for VM_FAULT_OOM, we simply sent a SIGKILL to current because we simply don't have memory to fault the page in, it's better to select a memory-hogging task to kill based on badness() than to constantly kill current which may not help in the long term. -- 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