From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753481AbcAGQ2z (ORCPT ); Thu, 7 Jan 2016 11:28:55 -0500 Received: from gum.cmpxchg.org ([85.214.110.215]:51424 "EHLO gum.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751515AbcAGQ2y (ORCPT ); Thu, 7 Jan 2016 11:28:54 -0500 Date: Thu, 7 Jan 2016 11:28:15 -0500 From: Johannes Weiner To: Tetsuo Handa Cc: mhocko@kernel.org, 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: <20160107162815.GA31729@cmpxchg.org> References: <201512292258.ABF87505.OFOSJLHMFVOQFt@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201512292258.ABF87505.OFOSJLHMFVOQFt@I-love.SAKURA.ne.jp> 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 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.