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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, 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 C57F5C433DB for ; Mon, 4 Jan 2021 08:11:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E52B20702 for ; Mon, 4 Jan 2021 08:11:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726602AbhADIL5 (ORCPT ); Mon, 4 Jan 2021 03:11:57 -0500 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:51424 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726306AbhADIL4 (ORCPT ); Mon, 4 Jan 2021 03:11:56 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R211e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=10;SR=0;TI=SMTPD_---0UKeYYmw_1609747872; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0UKeYYmw_1609747872) by smtp.aliyun-inc.com(127.0.0.1); Mon, 04 Jan 2021 16:11:13 +0800 Subject: Re: [PATCH] mm/memcontrol: fix warning in mem_cgroup_page_lruvec() To: Hugh Dickins , Andrew Morton Cc: Hui Su , Lorenzo Stoakes , Michal Hocko , Johannes Weiner , Shakeel Butt , Roman Gushchin , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: From: Alex Shi Message-ID: <2c1083cb-53d6-1cd6-9e1b-14a501db6f9a@linux.alibaba.com> Date: Mon, 4 Jan 2021 16:11:12 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.0; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=gbk Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Reviewed-by: Alex Shi ÔÚ 2021/1/4 ÏÂÎç1:03, Hugh Dickins дµÀ: > Boot a CONFIG_MEMCG=y kernel with "cgroup_disabled=memory" and you are > met by a series of warnings from the VM_WARN_ON_ONCE_PAGE(!memcg, page) > recently added to the inline mem_cgroup_page_lruvec(). > > An earlier attempt to place that warning, in mem_cgroup_lruvec(), had > been careful to do so after weeding out the mem_cgroup_disabled() case; > but was itself invalid because of the mem_cgroup_lruvec(NULL, pgdat) in > clear_pgdat_congested() and age_active_anon(). > > Warning in mem_cgroup_page_lruvec() was once useful in detecting a KSM > charge bug, so may be worth keeping: but skip if mem_cgroup_disabled(). > > Fixes: 9a1ac2288cf1 ("mm/memcontrol:rewrite mem_cgroup_page_lruvec()") > Signed-off-by: Hugh Dickins > --- > > include/linux/memcontrol.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- 5.11-rc2/include/linux/memcontrol.h 2020-12-27 20:39:36.751923135 -0800 > +++ linux/include/linux/memcontrol.h 2021-01-03 19:38:24.822978559 -0800 > @@ -665,7 +665,7 @@ static inline struct lruvec *mem_cgroup_ > { > struct mem_cgroup *memcg = page_memcg(page); > > - VM_WARN_ON_ONCE_PAGE(!memcg, page); > + VM_WARN_ON_ONCE_PAGE(!memcg && !mem_cgroup_disabled(), page); > return mem_cgroup_lruvec(memcg, pgdat); > } > >