From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755463AbZEIVia (ORCPT ); Sat, 9 May 2009 17:38:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755257AbZEIViQ (ORCPT ); Sat, 9 May 2009 17:38:16 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:52463 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754863AbZEIViO (ORCPT ); Sat, 9 May 2009 17:38:14 -0400 From: "Rafael J. Wysocki" To: David Rientjes Subject: Re: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag Date: Sat, 9 May 2009 23:37:38 +0200 User-Agent: KMail/1.11.2 (Linux/2.6.30-rc4-rjw; KDE/4.2.2; x86_64; ; ) Cc: Andrew Morton , fengguang.wu@intel.com, linux-pm@lists.linux-foundation.org, pavel@ucw.cz, Linus Torvalds , jens.axboe@oracle.com, alan-jenkins@tuffmail.co.uk, linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org, Mel Gorman References: <200905090155.44635.rjw@sisk.pl> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200905092337.39906.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Saturday 09 May 2009, David Rientjes wrote: > On Sat, 9 May 2009, Rafael J. Wysocki wrote: > > > > All of your tasks are in D state other than kthreads, right? That means > > > they won't be in the oom killer (thus no zones are oom locked), so you can > > > easily do this > > > > > > struct zone *z; > > > for_each_populated_zone(z) > > > zone_set_flag(z, ZONE_OOM_LOCKED); > > > > > > and then > > > > > > for_each_populated_zone(z) > > > zone_clear_flag(z, ZONE_OOM_LOCKED); > > > > > > The serialization is done with trylocks so this will never invoke the oom > > > killer because all zones in the allocator's zonelist will be oom locked. > > > > Well, that might have been a good idea if it actually had worked. :-( > > > > > Why does this not work for you? > > > > If I set image_size to something below "hard core working set" + > > totalreserve_pages, preallocate_image_memory() hangs the > > box (please refer to the last patch I sent, > > http://patchwork.kernel.org/patch/22423/). > > > > This has been changed in the latest mmotm with Mel's page alloactor > patches (and I think yours should be based on mmotm). Specifically, > page-allocator-break-up-the-allocator-entry-point-into-fast-and-slow-paths.patch. > > Before his patchset, zonelists that had ZONE_OOM_LOCKED set for at least > one of their zones would unconditionally goto restart. Now, if > order > PAGE_ALLOC_COSTLY_ORDER, it gives up and returns NULL. Otherwise, > it does goto restart. > > So if your allocation has order > PAGE_ALLOC_COSTLY_ORDER, It doesn't. All of my allocations are of order 0. > using the ZONE_OOM_LOCKED approach to locking out the oom killer will work > just fine in mmotm. No, it won't, AFAICT. Best, Rafael