Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933553Ab0BQC2Q (ORCPT ); Tue, 16 Feb 2010 21:28:16 -0500 Received: from smtp-out.google.com ([216.239.44.51]:38461 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933335Ab0BQC2O (ORCPT ); Tue, 16 Feb 2010 21:28:14 -0500 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id: references:user-agent:mime-version:content-type:x-system-of-record; b=hgD4qnHmPcbL7x0umjt+KwKDG+0S3AdkjCcniF1xRbW1cUiiM/ygMdJ8C9tlb37y9 Db2qud3hB7WwPB4EvV+vA== Date: Tue, 16 Feb 2010 18:28:05 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com 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 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> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1320 Lines: 30 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 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/