From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx110.postini.com [74.125.245.110]) by kanga.kvack.org (Postfix) with SMTP id 824EE6B0005 for ; Fri, 8 Feb 2013 11:40:59 -0500 (EST) Date: Fri, 8 Feb 2013 17:40:56 +0100 From: Michal Hocko Subject: Re: [PATCH for 3.2.34] memcg: do not trigger OOM from add_to_page_cache_locked Message-ID: <20130208164056.GG7557@dhcp22.suse.cz> References: <20130125163130.GF4721@dhcp22.suse.cz> <20130205134937.GA22804@dhcp22.suse.cz> <20130205154947.CD6411E2@pobox.sk> <20130205160934.GB22804@dhcp22.suse.cz> <20130205174651.GA3959@dhcp22.suse.cz> <20130205185953.GB3959@dhcp22.suse.cz> <20130208162918.GF7557@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130208162918.GF7557@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Greg Thelen Cc: azurIt , linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups mailinglist , KAMEZAWA Hiroyuki , Johannes Weiner On Fri 08-02-13 17:29:18, Michal Hocko wrote: [...] > OK, I have checked the allocator slow path and you are right even > GFP_KERNEL will not fail. This can lead to similar deadlocks - e.g. > OOM killed task blocked on down_write(mmap_sem) while the page fault > handler holding mmap_sem for reading and allocating a new page without > any progress. And now that I think about it some more it sounds like it shouldn't be possible because allocator would fail because it would see TIF_MEMDIE (OOM killer kills all threads that share the same mm). But maybe there are other locks that are dangerous, but I think that the risk is pretty low. -- Michal Hocko SUSE Labs -- 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