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=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 82424C433DF for ; Thu, 13 Aug 2020 11:01:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 20E4920866 for ; Thu, 13 Aug 2020 11:01:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 20E4920866 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7625F6B0002; Thu, 13 Aug 2020 07:01:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6EC506B0003; Thu, 13 Aug 2020 07:01:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 602786B0005; Thu, 13 Aug 2020 07:01:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0196.hostedemail.com [216.40.44.196]) by kanga.kvack.org (Postfix) with ESMTP id 473D16B0002 for ; Thu, 13 Aug 2020 07:01:06 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 02B975821 for ; Thu, 13 Aug 2020 11:01:06 +0000 (UTC) X-FDA: 77145253332.11.list05_5b0d8cb26ff3 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin11.hostedemail.com (Postfix) with ESMTP id 19E57180F8B8C for ; Thu, 13 Aug 2020 11:01:05 +0000 (UTC) X-HE-Tag: list05_5b0d8cb26ff3 X-Filterd-Recvd-Size: 2683 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Thu, 13 Aug 2020 11:01:04 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 9A84FB6A3; Thu, 13 Aug 2020 11:01:25 +0000 (UTC) Date: Thu, 13 Aug 2020 13:01:02 +0200 From: Michal Hocko To: Alex Shi Cc: akpm@linux-foundation.org, Johannes Weiner , Vladimir Davydov , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [Resend PATCH 2/6] mm/memcg: remove useless check on page->mem_cgroup Message-ID: <20200813110102.GF9477@dhcp22.suse.cz> References: <1597144232-11370-1-git-send-email-alex.shi@linux.alibaba.com> <1597144232-11370-2-git-send-email-alex.shi@linux.alibaba.com> <20200811113008.GK4793@dhcp22.suse.cz> <776b0e6f-4129-9fb9-0f66-47757cf320d5@linux.alibaba.com> <20200811135626.GL4793@dhcp22.suse.cz> <0b5e1ac3-c9c7-35e9-2661-b58430314d0a@linux.alibaba.com> <20200813062049.GA9477@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 19E57180F8B8C X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 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: On Thu 13-08-20 17:45:19, Alex Shi wrote: >=20 >=20 > =E5=9C=A8 2020/8/13 =E4=B8=8B=E5=8D=882:20, Michal Hocko =E5=86=99=E9=81= =93: > > On Wed 12-08-20 11:25:53, Alex Shi wrote: > >> >From 999b0fe5fc65865c3b59ff28500d45572a4a9570 Mon Sep 17 00:00:00 2= 001 > >> From: Alex Shi > >> Date: Wed, 5 Aug 2020 21:02:30 +0800 > >> Subject: [PATCH 2/6] mm/memcg: bail out early from swap accounting w= hen memcg > >> is disabled > >> > >> If we disabled memcg by cgroup_disable=3Dmemory, page->memcg will be= NULL > >> and so the charge is skipped and that will trigger a warning like be= low. > >> Let's return from the funcs earlier. > >> > >> ---[ end trace f1f34bfc3b32ed2f ]--- > >> anon flags:0x5005b48008000d(locked|uptodate|dirty|swapbacked) > >> raw: 005005b48008000d dead000000000100 dead000000000122 ffff8897c7c= 76ad1 > >> raw: 0000000000000022 0000000000000000 0000000200000000 00000000000= 00000 > >> page dumped because: VM_WARN_ON_ONCE_PAGE(!memcg) > >=20 > > Yes this is better. It would be even more informative if you added th= e > > backtrace. >=20 > The stack is a bit long. This doesn't matter. It is informative and potentially useful for future reference. Thanks! --=20 Michal Hocko SUSE Labs