From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751626AbaKFMt6 (ORCPT ); Thu, 6 Nov 2014 07:49:58 -0500 Received: from cantor2.suse.de ([195.135.220.15]:49505 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751133AbaKFMt4 (ORCPT ); Thu, 6 Nov 2014 07:49:56 -0500 Date: Thu, 6 Nov 2014 13:49:53 +0100 From: Michal Hocko To: Tejun Heo Cc: "Rafael J. Wysocki" , Andrew Morton , Cong Wang , David Rientjes , Oleg Nesterov , LKML , linux-mm@kvack.org, Linux PM list Subject: Re: [PATCH 3/4] OOM, PM: OOM killed task shouldn't escape PM suspend Message-ID: <20141106124953.GD7202@dhcp22.suse.cz> References: <20141105130247.GA14386@htj.dyndns.org> <20141105133100.GC4527@dhcp22.suse.cz> <20141105134219.GD4527@dhcp22.suse.cz> <20141105154436.GB14386@htj.dyndns.org> <20141105160115.GA28226@dhcp22.suse.cz> <20141105162929.GD14386@htj.dyndns.org> <20141105163956.GD28226@dhcp22.suse.cz> <20141105165428.GF14386@htj.dyndns.org> <20141105174609.GE28226@dhcp22.suse.cz> <20141105175527.GH14386@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141105175527.GH14386@htj.dyndns.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 05-11-14 12:55:27, Tejun Heo wrote: > On Wed, Nov 05, 2014 at 06:46:09PM +0100, Michal Hocko wrote: > > Because out_of_memory can be called from mutliple paths. And > > the only interesting one should be the page allocation path. > > pagefault_out_of_memory is not interesting because it cannot happen for > > the frozen task. > > Hmmm.... wouldn't that be broken by definition tho? So, if the oom > killer is invoked from somewhere else than page allocation path, it > would proceed ignoring the disabled setting and would race against PM > freeze path all the same. Not really because try_to_freeze_tasks doesn't finish until _all_ tasks are frozen and a task in the page fault path cannot be frozen, can it? I mean there shouldn't be any problem to not invoke OOM killer under from the page fault path as well but that might lead to looping in the page fault path without any progress until freezer enables OOM killer on the failure path because the said task cannot be frozen. Is this preferable? -- Michal Hocko SUSE Labs