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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT 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 CC2CDC433E1 for ; Mon, 24 Aug 2020 12:55:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B570F21775 for ; Mon, 24 Aug 2020 12:55:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727877AbgHXMzf (ORCPT ); Mon, 24 Aug 2020 08:55:35 -0400 Received: from out30-43.freemail.mail.aliyun.com ([115.124.30.43]:39562 "EHLO out30-43.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726968AbgHXMzW (ORCPT ); Mon, 24 Aug 2020 08:55:22 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R911e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07484;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=22;SR=0;TI=SMTPD_---0U6k9-bl_1598273712; Received: from aliy80.localdomain(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U6k9-bl_1598273712) by smtp.aliyun-inc.com(127.0.0.1); Mon, 24 Aug 2020 20:55:17 +0800 From: Alex Shi To: akpm@linux-foundation.org, mgorman@techsingularity.net, tj@kernel.org, hughd@google.com, khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com, willy@infradead.org, hannes@cmpxchg.org, lkp@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, shakeelb@google.com, iamjoonsoo.kim@lge.com, richard.weiyang@gmail.com, kirill@shutemov.name, alexander.duyck@gmail.com, rong.a.chen@intel.com, mhocko@suse.com, vdavydov.dev@gmail.com, shy828301@gmail.com Cc: Michal Hocko Subject: [PATCH v18 12/32] mm/memcg: optimize mem_cgroup_page_lruvec Date: Mon, 24 Aug 2020 20:54:45 +0800 Message-Id: <1598273705-69124-13-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1598273705-69124-1-git-send-email-alex.shi@linux.alibaba.com> References: <1598273705-69124-1-git-send-email-alex.shi@linux.alibaba.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hugh Dickins Add READ_ONCE on page->mem_cgroup, since we will check it later. Also the page should not be PageTail(page), so add a check. Signed-off-by: Hugh Dickins Signed-off-by: Alex Shi Cc: Andrew Morton Cc: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: cgroups@vger.kernel.org --- mm/memcontrol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 505f54087e82..65c1e873153e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1321,7 +1321,8 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd goto out; } - memcg = page->mem_cgroup; + VM_BUG_ON_PAGE(PageTail(page), page); + memcg = READ_ONCE(page->mem_cgroup); /* Readahead page is charged too, to see if other page uncharged */ VM_WARN_ON_ONCE_PAGE(!memcg, page); if (!memcg) -- 1.8.3.1