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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 C0F53C3A59E for ; Wed, 21 Aug 2019 06:47:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 87D5B22CF7 for ; Wed, 21 Aug 2019 06:47:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566370055; bh=yRPfh8F94y95g3H5Rd/+ScGD3gH1ptVeOngAdtWIq44=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=BIWodrFXuMpbMtBA1TIrpGWqi+B3v9sE2FV5NHCXllc3ka0O3Czt61M8rP6ctfUQ4 kgy/Q8TH3O655UMxM8iO9W5aBMXiXcALJammSvlxWeB1cVW/pGxpanUvBqdTwhX746 FYGsZ1No5yagUB6qNsO2ExlKwFmxyp9mcWxy7jSs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727643AbfHUGre (ORCPT ); Wed, 21 Aug 2019 02:47:34 -0400 Received: from mx2.suse.de ([195.135.220.15]:50746 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726372AbfHUGre (ORCPT ); Wed, 21 Aug 2019 02:47:34 -0400 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) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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