From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754821AbcHVKXA (ORCPT ); Mon, 22 Aug 2016 06:23:00 -0400 Received: from ud10.udmedia.de ([194.117.254.50]:35363 "EHLO mail.ud10.udmedia.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752984AbcHVKW7 (ORCPT ); Mon, 22 Aug 2016 06:22:59 -0400 Date: Mon, 22 Aug 2016 12:16:14 +0200 From: Markus Trippelsdorf To: Michal Hocko Cc: Andrew Morton , greg@suse.cz, Linus Torvalds , Arkadiusz Miskiewicz , Ralf-Peter Rohbeck , Jiri Slaby , Olaf Hering , Vlastimil Babka , Joonsoo Kim , linux-mm@kvack.org, LKML Subject: Re: OOM detection regressions since 4.7 Message-ID: <20160822101614.GA314@x4> References: <20160822093249.GA14916@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160822093249.GA14916@dhcp22.suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016.08.22 at 11:32 +0200, Michal Hocko wrote: > there have been multiple reports [1][2][3][4][5] about pre-mature OOM > killer invocations since 4.7 which contains oom detection rework. All of > them were for order-2 (kernel stack) alloaction requests failing because > of a high fragmentation and compaction failing to make any forward > progress. While investigating this we have found out that the compaction > just gives up too early. Vlastimil has been working on compaction > improvement for quite some time and his series [6] is already sitting > in mmotm tree. This already helps a lot because it drops some heuristics > which are more aimed at lower latencies for high orders rather than > reliability. Joonsoo has then identified further problem with too many > blocks being marked as unmovable [7] and Vlastimil has prepared a patch > on top of his series [8] which is also in the mmotm tree now. > > That being said, the regression is real and should be fixed for 4.7 > stable users. [6][8] was reported to help and ooms are no longer > reproducible. I know we are quite late (rc3) in 4.8 but I would vote > for mergeing those patches and have them in 4.8. For 4.7 I would go > with a partial revert of the detection rework for high order requests > (see patch below). This patch is really trivial. If those compaction > improvements are just too large for 4.8 then we can use the same patch > as for 4.7 stable for now and revert it in 4.9 after compaction changes > are merged. > > Thoughts? > > [1] http://lkml.kernel.org/r/20160731051121.GB307@x4 For the report [1] above: markus@x4 linux % cat .config | grep CONFIG_COMPACTION # CONFIG_COMPACTION is not set -- Markus