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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 DE956C10F27 for ; Wed, 11 Mar 2020 11:41:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8AC6721655 for ; Wed, 11 Mar 2020 11:41:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8AC6721655 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=I-love.SAKURA.ne.jp Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1BC706B0003; Wed, 11 Mar 2020 07:41:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 16D0F6B0006; Wed, 11 Mar 2020 07:41:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 083A86B0007; Wed, 11 Mar 2020 07:41:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0180.hostedemail.com [216.40.44.180]) by kanga.kvack.org (Postfix) with ESMTP id E289D6B0003 for ; Wed, 11 Mar 2020 07:41:53 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id AB0C35DD5 for ; Wed, 11 Mar 2020 11:41:53 +0000 (UTC) X-FDA: 76582892106.09.plane34_84d5505d5ee62 X-HE-Tag: plane34_84d5505d5ee62 X-Filterd-Recvd-Size: 2650 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Wed, 11 Mar 2020 11:41:52 +0000 (UTC) Received: from fsav101.sakura.ne.jp (fsav101.sakura.ne.jp [27.133.134.228]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 02BBfmMb037147; Wed, 11 Mar 2020 20:41:48 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav101.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav101.sakura.ne.jp); Wed, 11 Mar 2020 20:41:48 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav101.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 02BBflON037143 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 11 Mar 2020 20:41:47 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Subject: Re: [patch] mm, oom: make a last minute check to prevent unnecessary memcg oom kills To: David Rientjes Cc: Michal Hocko , Robert Kolchmeyer , Andrew Morton , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20200310221938.GF8447@dhcp22.suse.cz> From: Tetsuo Handa Message-ID: <54d56b12-3f75-1382-cc12-a8e63e24ce1f@I-love.SAKURA.ne.jp> Date: Wed, 11 Mar 2020 20:41:45 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 2020/03/11 7:54, David Rientjes wrote: > The patch certainly prevents unnecessary oom kills when there is a pending > victim that uncharges its memory between invoking the oom killer and > finding MMF_OOM_SKIP in the list of eligible tasks and its much more > common on systems with limited cpu cores. I think that it is dump_header() which currently spends much time (due to synchronous printing) enough to make "the second memcg oom kill shows usage is >40MB below its limit of 100MB" happen. Shouldn't we call dump_header() and then do the last check and end with "but did not kill anybody" message?