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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, 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 7FA5AC433E0 for ; Sat, 8 Aug 2020 13:23:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0B1FC20723 for ; Sat, 8 Aug 2020 13:23:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B1FC20723 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 3D5CB6B0002; Sat, 8 Aug 2020 09:23:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 35F226B0003; Sat, 8 Aug 2020 09:23:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 226EF6B0005; Sat, 8 Aug 2020 09:23:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0041.hostedemail.com [216.40.44.41]) by kanga.kvack.org (Postfix) with ESMTP id 081426B0002 for ; Sat, 8 Aug 2020 09:23:02 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id AC77E3A9E for ; Sat, 8 Aug 2020 13:23:01 +0000 (UTC) X-FDA: 77127466962.04.tree98_1a1506126fc9 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin04.hostedemail.com (Postfix) with ESMTP id 82A99800E2DF for ; Sat, 8 Aug 2020 13:23:01 +0000 (UTC) X-HE-Tag: tree98_1a1506126fc9 X-Filterd-Recvd-Size: 4051 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) by imf44.hostedemail.com (Postfix) with ESMTP for ; Sat, 8 Aug 2020 13:22:59 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0U56q4nE_1596892973; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U56q4nE_1596892973) by smtp.aliyun-inc.com(127.0.0.1); Sat, 08 Aug 2020 21:22:54 +0800 Subject: Re: [PATCH] mm/memcg: remove useless check on page->mem_cgroup From: Alex Shi To: Michal Hocko Cc: Johannes Weiner , Vladimir Davydov , Andrew Morton , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1596166480-22814-1-git-send-email-alex.shi@linux.alibaba.com> <20200731151655.GB491801@cmpxchg.org> <9338716f-ca0e-057f-8d94-03e2b3f70281@linux.alibaba.com> <20200803081815.GD5174@dhcp22.suse.cz> <92dd8e68-8095-72c5-0144-2a084e4d5993@linux.alibaba.com> <5622ef68-5e70-d1a9-d1be-b45411b6be5c@linux.alibaba.com> Message-ID: <4740bac1-72f6-a640-ab6a-a8801e68c27a@linux.alibaba.com> Date: Sat, 8 Aug 2020 21:22:29 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <5622ef68-5e70-d1a9-d1be-b45411b6be5c@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 X-Rspamd-Queue-Id: 82A99800E2DF X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 Content-Transfer-Encoding: quoted-printable 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: =E5=9C=A8 2020/8/5 =E4=B8=8B=E5=8D=889:02, Alex Shi =E5=86=99=E9=81=93: >=20 >=20 > =E5=9C=A8 2020/8/5 =E4=B8=8B=E5=8D=888:28, Alex Shi =E5=86=99=E9=81=93: >> The last patch has a problem on define. this version could fix it. >> >> BTW, I see some !memcg happens when MEMCG compilered but disabled by c= group_disable >> >> >> [ 94.657666] ---[ end trace f1f34bfc3b32ed2f ]--- >> [ 95.138995] anon flags: 0x5005b48008000d(locked|uptodate|dirty|swap= backed) >> [ 95.146220] raw: 005005b48008000d dead000000000100 dead000000000122= ffff8897c7c76ad1 >> [ 95.154549] raw: 0000000000000022 0000000000000000 0000000200000000= 0000000000000000 >> [ 95.162876] page dumped because: VM_WARN_ON_ONCE_PAGE(!memcg) >> >> >=20 > The following patch may helpful. Any comments for the 2 patches? Thanks Alex >=20 > From 8bfb26a2e37e08dc61d20212bcfa5812a367ba94 Mon Sep 17 00:00:00 2001 > From: Alex Shi > Date: Wed, 5 Aug 2020 20:32:12 +0800 > Subject: [PATCH] mm/memcg: don't try charge swap if memcg disabled >=20 > If we disabled memcg by cgroup_disable=3Dmemory, the swap charges are > still called. Let's return from the funcs earlier and keep WARN_ON > monitor. >=20 > Signed-off-by: Alex Shi > Cc: Johannes Weiner > Cc: Michal Hocko > Cc: Vladimir Davydov > Cc: Andrew Morton > Cc: cgroups@vger.kernel.org > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > --- > mm/memcontrol.c | 6 ++++++ > 1 file changed, 6 insertions(+) >=20 > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index cb07a48d53aa..65f2b42d25af 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -7163,6 +7163,9 @@ void mem_cgroup_swapout(struct page *page, swp_en= try_t entry) > VM_BUG_ON_PAGE(PageLRU(page), page); > VM_BUG_ON_PAGE(page_count(page), page); > =20 > + if (mem_cgroup_disabled()) > + return; > + > if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) > return; > =20 > @@ -7228,6 +7231,9 @@ int mem_cgroup_try_charge_swap(struct page *page,= swp_entry_t entry) > struct mem_cgroup *memcg; > unsigned short oldid; > =20 > + if (mem_cgroup_disabled()) > + return 0; > + > if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) > return 0; > =20 >=20