Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760961AbcLBRPp (ORCPT ); Fri, 2 Dec 2016 12:15:45 -0500 Received: from 001b2d01.pphosted.com ([148.163.156.1]:39930 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754040AbcLBRPn (ORCPT ); Fri, 2 Dec 2016 12:15:43 -0500 Date: Fri, 2 Dec 2016 09:15:42 -0800 From: "Paul E. McKenney" To: Michal Hocko Cc: Boris Zhmurov , Paul Menzel , Donald Buczek , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Reply-To: paulmck@linux.vnet.ibm.com References: <20161128150509.GG3924@linux.vnet.ibm.com> <66fd50e1-a922-846a-f427-7654795bd4b5@kernelpanic.ru> <20161130174802.GM18432@dhcp22.suse.cz> <20161130182552.GN18432@dhcp22.suse.cz> <20161202164408.GM3924@linux.vnet.ibm.com> <20161202170248.GT6830@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161202170248.GT6830@dhcp22.suse.cz> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16120217-0020-0000-0000-00000A6AE746 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006180; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000193; SDB=6.00788398; UDB=6.00381477; IPR=6.00566073; BA=6.00004937; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00013515; XFM=3.00000011; UTC=2016-12-02 17:15:41 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16120217-0021-0000-0000-000057C5C1FE Message-Id: <20161202171542.GO3924@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-12-02_12:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1612020263 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1538 Lines: 40 On Fri, Dec 02, 2016 at 06:02:49PM +0100, Michal Hocko wrote: > On Fri 02-12-16 08:44:08, Paul E. McKenney wrote: > > On Fri, Dec 02, 2016 at 07:39:24PM +0300, Boris Zhmurov wrote: > > > Paul E. McKenney Thu Dec 01 2016 - 14:39:21 EST: > > > > > > >> Well, I can confirm, that replacing cond_resched_rcu_qs in > > > >> shrink_node_memcg by cond_resched also makes dmesg clean from RCU > > > >> CPU stall warnings. > > > >> > > > >> I've attached patch (just modification of Paul's patch), that > > > >> fixes RCU stall messages in situations, when all memory is used by > > > >> couchbase/memcached + fs cache and linux starts to use swap. > > > > > > > Nice! Just to double-check, could you please also test your patch > > > > above with these two commits from -rcu? > > > > > > > > d2db185bfee8 ("rcu: Remove short-term CPU kicking") f8f127e738e3 > > > > ("rcu: Add long-term CPU kicking") > > > > > > > > Thanx, Paul > > > > > > > > > Looks like patches d2db185bfee8 and f8f127e738e3 change nothing. > > > > > > With cond_resched() in shrink_node_memcg and these two patches dmesg is > > > clean. No any RCU CPU stall messages. > > > > Very good! I have these two patches queued for 4.11. > > FWIW I have posted the cond_resched patch to Andrew [1]. I didn't CC you > Paul to save you from emails as this is more MM than anything else > related ;) > > [1] http://lkml.kernel.org/r/20161202095841.16648-1-mhocko@kernel.org Feel free to apply: Acked-by: Paul E. McKenney Thanx, Paul