From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754946AbcAHMhk (ORCPT ); Fri, 8 Jan 2016 07:37:40 -0500 Received: from mail-wm0-f45.google.com ([74.125.82.45]:38849 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753507AbcAHMhj (ORCPT ); Fri, 8 Jan 2016 07:37:39 -0500 Date: Fri, 8 Jan 2016 13:37:36 +0100 From: Michal Hocko To: Johannes Weiner Cc: Tetsuo Handa , akpm@linux-foundation.org, mgorman@suse.de, rientjes@google.com, torvalds@linux-foundation.org, oleg@redhat.com, hughd@google.com, andrea@kernel.org, riel@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm,oom: Exclude TIF_MEMDIE processes from candidates. Message-ID: <20160108123735.GB14657@dhcp22.suse.cz> References: <201512292258.ABF87505.OFOSJLHMFVOQFt@I-love.SAKURA.ne.jp> <20160107162815.GA31729@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160107162815.GA31729@cmpxchg.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 07-01-16 11:28:15, Johannes Weiner wrote: > On Tue, Dec 29, 2015 at 10:58:22PM +0900, Tetsuo Handa wrote: > > >From 8bb9e36891a803e82c589ef78077838026ce0f7d Mon Sep 17 00:00:00 2001 > > From: Tetsuo Handa > > Date: Tue, 29 Dec 2015 22:20:58 +0900 > > Subject: [PATCH] mm,oom: Exclude TIF_MEMDIE processes from candidates. > > > > The OOM reaper kernel thread can reclaim OOM victim's memory before the victim > > terminates. But since oom_kill_process() tries to kill children of the memory > > hog process first, the OOM reaper can not reclaim enough memory for terminating > > the victim if the victim is consuming little memory. The result is OOM livelock > > as usual, for timeout based next OOM victim selection is not implemented. > > What we should be doing is have the OOM reaper clear TIF_MEMDIE after > it's done. There is no reason to wait for and prioritize the exit of a > task that doesn't even have memory anymore. Once a task's memory has > been reaped, subsequent OOM invocations should evaluate anew the most > desirable OOM victim. This is an interesting idea. It definitely sounds better than timeout based solutions. I will cook up a patch for this. The API between oom killer and the reaper has to change slightly but that shouldn't be a big deal. Thanks! -- Michal Hocko SUSE Labs