From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx186.postini.com [74.125.245.186]) by kanga.kvack.org (Postfix) with SMTP id 81D406B0095 for ; Fri, 19 Oct 2012 16:34:07 -0400 (EDT) Received: by mail-pb0-f41.google.com with SMTP id rq2so763152pbb.14 for ; Fri, 19 Oct 2012 13:34:06 -0700 (PDT) Date: Fri, 19 Oct 2012 13:34:04 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH v5 06/14] memcg: kmem controller infrastructure In-Reply-To: <5081269B.5000603@parallels.com> Message-ID: References: <1350382611-20579-1-git-send-email-glommer@parallels.com> <1350382611-20579-7-git-send-email-glommer@parallels.com> <507FCA90.8060307@parallels.com> <5081269B.5000603@parallels.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Glauber Costa Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, Mel Gorman , Tejun Heo , Andrew Morton , Michal Hocko , Johannes Weiner , KAMEZAWA Hiroyuki , Christoph Lameter , Pekka Enberg , devel@openvz.org, linux-kernel@vger.kernel.org, Pekka Enberg On Fri, 19 Oct 2012, Glauber Costa wrote: > >>> What about gfp & __GFP_FS? > >>> > >> > >> Do you intend to prevent or allow OOM under that flag? I personally > >> think that anything that accepts to be OOM-killed should have GFP_WAIT > >> set, so that ought to be enough. > >> > > > > The oom killer in the page allocator cannot trigger without __GFP_FS > > because direct reclaim has little chance of being very successful and > > thus we end up needlessly killing processes, and that tends to happen > > quite a bit if we dont check for it. Seems like this would also happen > > with memcg if mem_cgroup_reclaim() has a large probability of failing? > > > > I can indeed see tests for GFP_FS in some key locations in mm/ before > calling the OOM Killer. > > Should I test for GFP_IO as well? It's not really necessary, if __GFP_IO isn't set then it wouldn't make sense for __GFP_FS to be set. > If the idea is preventing OOM to > trigger for allocations that can write their pages back, how would you > feel about the following test: > > may_oom = (gfp & GFP_KERNEL) && !(gfp & __GFP_NORETRY) ? > I would simply copy the logic from the page allocator and only trigger oom for __GFP_FS and !__GFP_NORETRY. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org