From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Date: Fri, 8 May 2009 01:24:18 +0200 Message-ID: <200905080124.19794.rjw@sisk.pl> References: <200905080050.41973.rjw@sisk.pl> <20090507161508.42f586ef.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090507161508.42f586ef.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> Content-Disposition: inline Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: Text/Plain; charset="us-ascii" To: Andrew Morton 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 Friday 08 May 2009, Andrew Morton wrote: > 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. Understood. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756749AbZEGXZ0 (ORCPT ); Thu, 7 May 2009 19:25:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752004AbZEGXZM (ORCPT ); Thu, 7 May 2009 19:25:12 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:39456 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751084AbZEGXZK (ORCPT ); Thu, 7 May 2009 19:25:10 -0400 From: "Rafael J. Wysocki" To: Andrew Morton Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Date: Fri, 8 May 2009 01:24:18 +0200 User-Agent: KMail/1.11.2 (Linux/2.6.30-rc4-rjw; KDE/4.2.2; x86_64; ; ) 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 References: <200905080050.41973.rjw@sisk.pl> <20090507161508.42f586ef.akpm@linux-foundation.org> In-Reply-To: <20090507161508.42f586ef.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200905080124.19794.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 08 May 2009, Andrew Morton wrote: > 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. Understood.