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=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 510AFC433E3 for ; Tue, 14 Jul 2020 12:47:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1CA0422453 for ; Tue, 14 Jul 2020 12:47:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1CA0422453 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 AB2546B0002; Tue, 14 Jul 2020 08:47:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A88E96B0003; Tue, 14 Jul 2020 08:47:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9C6B76B0005; Tue, 14 Jul 2020 08:47:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0110.hostedemail.com [216.40.44.110]) by kanga.kvack.org (Postfix) with ESMTP id 850016B0002 for ; Tue, 14 Jul 2020 08:47:19 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 1CA36181AC9C6 for ; Tue, 14 Jul 2020 12:47:19 +0000 (UTC) X-FDA: 77036656998.23.turn94_02016df26ef1 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id E071337613 for ; Tue, 14 Jul 2020 12:47:18 +0000 (UTC) X-HE-Tag: turn94_02016df26ef1 X-Filterd-Recvd-Size: 2196 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Jul 2020 12:47:17 +0000 (UTC) Received: from fsav404.sakura.ne.jp (fsav404.sakura.ne.jp [133.242.250.103]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 06ECl64e039279; Tue, 14 Jul 2020 21:47:06 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav404.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav404.sakura.ne.jp); Tue, 14 Jul 2020 21:47:06 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav404.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 06ECl5HS039274 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 14 Jul 2020 21:47:06 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: [PATCH] mm, oom: check memcg margin for parallel oom To: Michal Hocko , Yafang Shao Cc: rientjes@google.com, akpm@linux-foundation.org, linux-mm@kvack.org References: <1594728512-18969-1-git-send-email-laoar.shao@gmail.com> <20200714123726.GI24642@dhcp22.suse.cz> From: Tetsuo Handa Message-ID: <83fececb-924c-0e1b-8e48-547b93593650@i-love.sakura.ne.jp> Date: Tue, 14 Jul 2020 21:47:06 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200714123726.GI24642@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: E071337613 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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 2020/07/14 21:37, Michal Hocko wrote: > - if (mutex_lock_killable(&oom_lock)) > + if (!mutex_trylock(&oom_lock)) > return true; I don't like this change. The trylock needlessly wastes CPU time which could have been utilized by the OOM killer/reaper for reclaiming memory. Rather, I want to change - if (!mutex_trylock(&oom_lock)) { + if (mutex_lock_killable(&oom_lock)) { in __alloc_pages_may_oom() side.