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=-0.8 required=3.0 tests=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 068BEC2BA19 for ; Wed, 15 Apr 2020 11:37:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B06E12078A for ; Wed, 15 Apr 2020 11:37:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B06E12078A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-vserver.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6604B8E0010; Wed, 15 Apr 2020 07:37:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 60F9F8E0001; Wed, 15 Apr 2020 07:37:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 54CD08E0010; Wed, 15 Apr 2020 07:37:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0029.hostedemail.com [216.40.44.29]) by kanga.kvack.org (Postfix) with ESMTP id 3C58C8E0001 for ; Wed, 15 Apr 2020 07:37:39 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 01B4321E4 for ; Wed, 15 Apr 2020 11:37:39 +0000 (UTC) X-FDA: 76709889438.18.pets35_5fb7e37683e1d X-HE-Tag: pets35_5fb7e37683e1d X-Filterd-Recvd-Size: 3409 Received: from smtprelay.restena.lu (smtprelay.restena.lu [158.64.1.62]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Wed, 15 Apr 2020 11:37:37 +0000 (UTC) Received: from hemera.lan.sysophe.eu (unknown [IPv6:2001:a18:1:12::4]) by smtprelay.restena.lu (Postfix) with ESMTPS id 2577340FCB; Wed, 15 Apr 2020 13:37:29 +0200 (CEST) Date: Wed, 15 Apr 2020 13:37:28 +0200 From: Bruno =?UTF-8?B?UHLDqW1vbnQ=?= To: Michal Hocko Cc: Chris Down , cgroups@vger.kernel.org, linux-mm@kvack.org, Johannes Weiner , Vladimir Davydov Subject: Re: Memory CG and 5.1 to 5.6 uprade slows backup Message-ID: <20200415133728.3f58d46e@hemera.lan.sysophe.eu> In-Reply-To: <20200415102442.GE4629@dhcp22.suse.cz> References: <20200409094615.GE18386@dhcp22.suse.cz> <20200409121733.1a5ba17c@hemera.lan.sysophe.eu> <20200409103400.GF18386@dhcp22.suse.cz> <20200409170926.182354c3@hemera.lan.sysophe.eu> <20200409152540.GP18386@dhcp22.suse.cz> <20200410091525.287062fa@hemera.lan.sysophe.eu> <20200410104343.5bcde519@hemera.lan.sysophe.eu> <20200410115010.1d9f6a3f@hemera.lan.sysophe.eu> <20200414163134.GQ4629@dhcp22.suse.cz> <20200415121753.3c8d700b@hemera.lan.sysophe.eu> <20200415102442.GE4629@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 Wed, 15 Apr 2020 12:24:42 Michal Hocko wrote: > On Wed 15-04-20 12:17:53, Bruno Pr=C3=A9mont wrote: > [...] > > > Anyway the following simply tracing patch should give a better clue. > > > The output will appear in the trace buffer (mount tracefs and read > > > trace_pipe file). =20 > >=20 > > This is the output I get on 5.6.4 with simple tar -zc call (max=3Dhigh+= 4096): > > tar-16943 [000] .... 1098.796955: mem_cgroup_handle_over_high: memcg= _nr_pages_over_high:1 penalty_jiffies:200 current:262122 high:262144 > > tar-16943 [000] .... 1100.876794: mem_cgroup_handle_over_high: memcg= _nr_pages_over_high:1 penalty_jiffies:200 current:262122 high:262144 > > tar-16943 [000] .... 1102.956636: mem_cgroup_handle_over_high: memcg= _nr_pages_over_high:1 penalty_jiffies:200 current:262120 high:262144 > > tar-16943 [000] .... 1105.037388: mem_cgroup_handle_over_high: memcg= _nr_pages_over_high:1 penalty_jiffies:200 current:262121 high:262144 > > tar-16943 [000] .... 1107.117246: mem_cgroup_handle_over_high: memcg= _nr_pages_over_high:1 penalty_jiffies:200 current:262122 high:262144 =20 >=20 > OK, that points to the underflow fix. >=20 > >=20 > > With 5.7-rc1 it runs just fine, pressure remains zero and no output in = trace_pipe or throttling. > >=20 > > So the fixes that went in there do fix it. > > Now matter of cherry-picking the right ones... e26733e0d0ec and its fix= e's fix, > > maybe some others (will start with those tagged for stable). =20 >=20 > I have seen Greg picking up this for stable trees so it should show up > there soon. Applying just 9b8b17541f13809d06f6f873325305ddbb760e3e which went to stable-rc for 5.6.5 gets things running fine where. (e26733e0d0ec seems to have gone in shortly prior to 5.6 release, need to improve my git-foo to locate commits between tags!) So yes it's the fix. Thanks, Bruno > Thanks!