From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757618AbZEGXVj (ORCPT ); Thu, 7 May 2009 19:21:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754049AbZEGXV2 (ORCPT ); Thu, 7 May 2009 19:21:28 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:60096 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753330AbZEGXV1 (ORCPT ); Thu, 7 May 2009 19:21:27 -0400 Date: Thu, 7 May 2009 16:15:08 -0700 From: Andrew Morton To: "Rafael J. Wysocki" Cc: rientjes@google.com, fengguang.wu@intel.com, linux-pm@lists.linux-foundation.org, pavel@ucw.cz, torvalds@linux-foundation.org, jens.axboe@oracle.com, alan-jenkins@tuffmail.co.uk, linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Message-Id: <20090507161508.42f586ef.akpm@linux-foundation.org> In-Reply-To: <200905080050.41973.rjw@sisk.pl> References: <200905080014.49426.rjw@sisk.pl> <20090507153824.df54658c.akpm@linux-foundation.org> <200905080050.41973.rjw@sisk.pl> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.20; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 8 May 2009 00:50:41 +0200 "Rafael J. Wysocki" wrote: > On Friday 08 May 2009, Andrew Morton wrote: > > On Fri, 8 May 2009 00:14:48 +0200 > > "Rafael J. Wysocki" wrote: > > > > > IOW, you need to freeze the user space totally before trying to disable the > > > OOM killer. > > > > Not necessarily. We only need to take action if a task is about to > > start oom-killing - presumably by taking a nap. > > > > If a process is sitting there happily computing pi then we can leave it > > running. > > Well, the point is we don't really know what the task is going to do next. > Is it going to continue computing pi, or is it going to execl(huge_binary), for > example? > > If we knew what tasks were going to do in advance, the whole freezing wouldn't > really be necessary. :-) argh. Third time: - if the task is computing pi, let it do so. - if the task tries to allocate memory and succeeds, let it proceed. - if the task tries to allocate memory and fails and then tries to invoke the oom-killer, stop the task. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Date: Thu, 7 May 2009 16:15:08 -0700 Message-ID: <20090507161508.42f586ef.akpm@linux-foundation.org> References: <200905080014.49426.rjw@sisk.pl> <20090507153824.df54658c.akpm@linux-foundation.org> <200905080050.41973.rjw@sisk.pl> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200905080050.41973.rjw-KKrjLPT3xs0@public.gmane.org> Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: "Rafael J. Wysocki" Cc: rientjes-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, fengguang.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, linux-pm-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, pavel-+ZI9xUNit7I@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, alan-jenkins-cCz0Lq7MMjm9FHfhHBbuYA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Fri, 8 May 2009 00:50:41 +0200 "Rafael J. Wysocki" wrote: > On Friday 08 May 2009, Andrew Morton wrote: > > On Fri, 8 May 2009 00:14:48 +0200 > > "Rafael J. Wysocki" wrote: > > > > > IOW, you need to freeze the user space totally before trying to disable the > > > OOM killer. > > > > Not necessarily. We only need to take action if a task is about to > > start oom-killing - presumably by taking a nap. > > > > If a process is sitting there happily computing pi then we can leave it > > running. > > Well, the point is we don't really know what the task is going to do next. > Is it going to continue computing pi, or is it going to execl(huge_binary), for > example? > > If we knew what tasks were going to do in advance, the whole freezing wouldn't > really be necessary. :-) argh. Third time: - if the task is computing pi, let it do so. - if the task tries to allocate memory and succeeds, let it proceed. - if the task tries to allocate memory and fails and then tries to invoke the oom-killer, stop the task.