From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33BD5C3A5A1 for ; Wed, 21 Aug 2019 06:47:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 00B422089E for ; Wed, 21 Aug 2019 06:47:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 00B422089E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A28876B029B; Wed, 21 Aug 2019 02:47:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9D9826B029C; Wed, 21 Aug 2019 02:47:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8EEBD6B029D; Wed, 21 Aug 2019 02:47:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0071.hostedemail.com [216.40.44.71]) by kanga.kvack.org (Postfix) with ESMTP id 6717D6B029B for ; Wed, 21 Aug 2019 02:47:35 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 075B98248AC4 for ; Wed, 21 Aug 2019 06:47:35 +0000 (UTC) X-FDA: 75845504070.28.geese06_7f39d1b24046 X-HE-Tag: geese06_7f39d1b24046 X-Filterd-Recvd-Size: 3229 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Wed, 21 Aug 2019 06:47:34 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id D59E2ABE3; Wed, 21 Aug 2019 06:47:32 +0000 (UTC) Date: Wed, 21 Aug 2019 08:47:32 +0200 From: Michal Hocko To: David Rientjes Cc: Edward Chron , Andrew Morton , Roman Gushchin , Johannes Weiner , Tetsuo Handa , Shakeel Butt , linux-mm@kvack.org, linux-kernel@vger.kernel.org, colona@arista.com Subject: Re: [PATCH] mm/oom: Add oom_score_adj value to oom Killed process message Message-ID: <20190821064732.GW3111@dhcp22.suse.cz> References: <20190821001445.32114-1-echron@arista.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue 20-08-19 20:25:32, David Rientjes wrote: > On Tue, 20 Aug 2019, Edward Chron wrote: > > > For an OOM event: print oom_score_adj value for the OOM Killed process to > > document what the oom score adjust value was at the time the process was > > OOM Killed. The adjustment value can be set by user code and it affects > > the resulting oom_score so it is used to influence kill process selection. > > > > When eligible tasks are not printed (sysctl oom_dump_tasks = 0) printing > > this value is the only documentation of the value for the process being > > killed. Having this value on the Killed process message documents if a > > miscconfiguration occurred or it can confirm that the oom_score_adj > > value applies as expected. > > > > An example which illustates both misconfiguration and validation that > > the oom_score_adj was applied as expected is: > > > > Aug 14 23:00:02 testserver kernel: Out of memory: Killed process 2692 > > (systemd-udevd) total-vm:1056800kB, anon-rss:1052760kB, file-rss:4kB, > > shmem-rss:0kB oom_score_adj:1000 > > > > The systemd-udevd is a critical system application that should have an > > oom_score_adj of -1000. Here it was misconfigured to have a adjustment > > of 1000 making it a highly favored OOM kill target process. The output > > documents both the misconfiguration and the fact that the process > > was correctly targeted by OOM due to the miconfiguration. Having > > the oom_score_adj on the Killed message ensures that it is documented. > > > > Signed-off-by: Edward Chron > > Acked-by: Michal Hocko > > Acked-by: David Rientjes > > vm.oom_dump_tasks is pretty useful, however, so it's curious why you > haven't left it enabled :/ Because it generates a lot of output potentially. Think of a workload with too many tasks which is not uncommon. -- Michal Hocko SUSE Labs