From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754949AbZEGTdz (ORCPT ); Thu, 7 May 2009 15:33:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753046AbZEGTdo (ORCPT ); Thu, 7 May 2009 15:33:44 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:38263 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750912AbZEGTdn (ORCPT ); Thu, 7 May 2009 15:33:43 -0400 From: "Rafael J. Wysocki" To: Andrew Morton Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Date: Thu, 7 May 2009 21:33:47 +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: <200905072009.53406.rjw@sisk.pl> <20090507114807.d7c6d26a.akpm@linux-foundation.org> In-Reply-To: <20090507114807.d7c6d26a.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: <200905072133.48917.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 07 May 2009, Andrew Morton wrote: > On Thu, 7 May 2009 20:09:52 +0200 > "Rafael J. Wysocki" wrote: > > > > > > I'm suspecting that hibernation can allocate its pages with > > > > > __GFP_FS|__GFP_WAIT|__GFP_NORETRY|__GFP_NOWARN, and the page allocator > > > > > will dtrt: no oom-killings. > > > > > > > > > > In which case, processes_are_frozen() is not needed at all? > > > > > > > > __GFP_NORETRY alone causes it to fail relatively quickly, but I'll try with > > > > the combination. > > > > > > OK. __GFP_WAIT is the big hammer. > > > > Unfortunately it fails too quickly with the combination as well, so it looks > > like we can't use __GFP_NORETRY during hibernation. > > hm. > > So where do we stand now? > > I'm not a big fan of the global application-specific state change > thing. Something like __GFP_NO_OOM_KILL has a better chance of being > reused by other subsystems in the future, which is a good indicator. I'm not against __GFP_NO_OOM_KILL, but there's been some strong resistance to adding new _GPF _FOO flags recently. Is there any likelihood anyone else we'll really need it any time soon? The advantage of the freezer-based approach is that it disables the OOM killer when it's not going to work anyway, so it looks like a reasonable thing to do regardless. IMHO. 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: Thu, 7 May 2009 21:33:47 +0200 Message-ID: <200905072133.48917.rjw@sisk.pl> References: <200905072009.53406.rjw@sisk.pl> <20090507114807.d7c6d26a.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090507114807.d7c6d26a.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 Thursday 07 May 2009, Andrew Morton wrote: > On Thu, 7 May 2009 20:09:52 +0200 > "Rafael J. Wysocki" wrote: > > > > > > I'm suspecting that hibernation can allocate its pages with > > > > > __GFP_FS|__GFP_WAIT|__GFP_NORETRY|__GFP_NOWARN, and the page allocator > > > > > will dtrt: no oom-killings. > > > > > > > > > > In which case, processes_are_frozen() is not needed at all? > > > > > > > > __GFP_NORETRY alone causes it to fail relatively quickly, but I'll try with > > > > the combination. > > > > > > OK. __GFP_WAIT is the big hammer. > > > > Unfortunately it fails too quickly with the combination as well, so it looks > > like we can't use __GFP_NORETRY during hibernation. > > hm. > > So where do we stand now? > > I'm not a big fan of the global application-specific state change > thing. Something like __GFP_NO_OOM_KILL has a better chance of being > reused by other subsystems in the future, which is a good indicator. I'm not against __GFP_NO_OOM_KILL, but there's been some strong resistance to adding new _GPF _FOO flags recently. Is there any likelihood anyone else we'll really need it any time soon? The advantage of the freezer-based approach is that it disables the OOM killer when it's not going to work anyway, so it looks like a reasonable thing to do regardless. IMHO.