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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 9C334C3F2D7 for ; Wed, 4 Mar 2020 07:19:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 672212166E for ; Wed, 4 Mar 2020 07:19:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 672212166E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 04B6E6B0003; Wed, 4 Mar 2020 02:19:55 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F3DB26B0005; Wed, 4 Mar 2020 02:19:54 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E54016B0006; Wed, 4 Mar 2020 02:19:54 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0120.hostedemail.com [216.40.44.120]) by kanga.kvack.org (Postfix) with ESMTP id CB2EB6B0003 for ; Wed, 4 Mar 2020 02:19:54 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 89E1D5DF2 for ; Wed, 4 Mar 2020 07:19:54 +0000 (UTC) X-FDA: 76556830308.08.bread95_394c2a894810b X-HE-Tag: bread95_394c2a894810b X-Filterd-Recvd-Size: 2264 Received: from out30-44.freemail.mail.aliyun.com (out30-44.freemail.mail.aliyun.com [115.124.30.44]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Wed, 4 Mar 2020 07:19:53 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07488;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=16;SR=0;TI=SMTPD_---0TrcXp76_1583306386; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0TrcXp76_1583306386) by smtp.aliyun-inc.com(127.0.0.1); Wed, 04 Mar 2020 15:19:46 +0800 Subject: Re: [PATCH v9 02/20] mm/memcg: fold lock_page_lru into commit_charge To: Hillf Danton Cc: cgroups@vger.kernel.org, akpm@linux-foundation.org, mgorman@techsingularity.net, tj@kernel.org, hughd@google.com, khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com, yang.shi@linux.alibaba.com, willy@infradead.org, hannes@cmpxchg.org, lkp@intel.com, Michal Hocko , Vladimir Davydov , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1583146830-169516-1-git-send-email-alex.shi@linux.alibaba.com> <20200304031335.9784-1-hdanton@sina.com> From: Alex Shi Message-ID: <4131e7d9-acad-4372-73b1-6fa1b0b251ef@linux.alibaba.com> Date: Wed, 4 Mar 2020 15:19:46 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200304031335.9784-1-hdanton@sina.com> Content-Type: text/plain; charset=gbk Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.008147, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: =D4=DA 2020/3/4 =C9=CF=CE=E711:13, Hillf Danton =D0=B4=B5=C0: >> * Nobody should be changing or seriously looking at >> * page->mem_cgroup at this point: >> @@ -2633,8 +2611,13 @@ static void commit_charge(struct page *page, st= ruct mem_cgroup *memcg, >> */ >> page->mem_cgroup =3D memcg; >> =20 > Well it is likely to update memcg for page without lru_lock held even i= f > more care is required, which is a change added in the current semantic = and > worth a line of words in log. >=20 the lru_lock is guard for lru list, not for page->mem_cgroup, seem no nee= d to highlight this point. Do we? Thanks Alex