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=-3.8 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 B9071C433DF for ; Wed, 26 Aug 2020 11:00:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 87C9A2071E for ; Wed, 26 Aug 2020 11:00:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 87C9A2071E 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 0D74F6B0003; Wed, 26 Aug 2020 07:00:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0862A6B0005; Wed, 26 Aug 2020 07:00:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F05486B0006; Wed, 26 Aug 2020 07:00:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0184.hostedemail.com [216.40.44.184]) by kanga.kvack.org (Postfix) with ESMTP id DB28A6B0003 for ; Wed, 26 Aug 2020 07:00:18 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 90DC9824934B for ; Wed, 26 Aug 2020 11:00:18 +0000 (UTC) X-FDA: 77192425716.02.hope31_181812a27063 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id 50F3910097AA4 for ; Wed, 26 Aug 2020 11:00:18 +0000 (UTC) X-HE-Tag: hope31_181812a27063 X-Filterd-Recvd-Size: 1914 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Wed, 26 Aug 2020 11:00:17 +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 C457DACA0; Wed, 26 Aug 2020 11:00:47 +0000 (UTC) Date: Wed, 26 Aug 2020 13:00:15 +0200 From: Michal Hocko To: xunlei Cc: Johannes Weiner , Andrew Morton , Vladimir Davydov , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm: memcg: Fix memcg reclaim soft lockup Message-ID: <20200826110015.GO22869@dhcp22.suse.cz> References: <1598426822-93737-1-git-send-email-xlpang@linux.alibaba.com> <20200826081102.GM22869@dhcp22.suse.cz> <99efed0e-050a-e313-46ab-8fe6228839d5@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <99efed0e-050a-e313-46ab-8fe6228839d5@linux.alibaba.com> X-Rspamd-Queue-Id: 50F3910097AA4 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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 26-08-20 18:41:18, xunlei wrote: > On 2020/8/26 =E4=B8=8B=E5=8D=884:11, Michal Hocko wrote: > > On Wed 26-08-20 15:27:02, Xunlei Pang wrote: > >> We've met softlockup with "CONFIG_PREEMPT_NONE=3Dy", when > >> the target memcg doesn't have any reclaimable memory. > >=20 > > Do you have any scenario when this happens or is this some sort of a > > test case? >=20 > It can happen on tiny guest scenarios. OK, you made me more curious. If this is a tiny guest and this is a hard limit reclaim path then we should trigger an oom killer which should kill the offender and that in turn bail out from the try_charge lopp (see should_force_charge). So how come this repeats enough in your setup that it causes soft lockups? --=20 Michal Hocko SUSE Labs