From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753973AbcLBQo6 (ORCPT ); Fri, 2 Dec 2016 11:44:58 -0500 Received: from 001b2d01.pphosted.com ([148.163.156.1]:56383 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753905AbcLBQob (ORCPT ); Fri, 2 Dec 2016 11:44:31 -0500 Date: Fri, 2 Dec 2016 08:44:08 -0800 From: "Paul E. McKenney" To: Boris Zhmurov Cc: Michal Hocko , 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: <3a4242cb-0198-0a3b-97ae-536fb5ff83ec@kernelpanic.ru> <20161128143435.GC3924@linux.vnet.ibm.com> <20161128150509.GG3924@linux.vnet.ibm.com> <66fd50e1-a922-846a-f427-7654795bd4b5@kernelpanic.ru> <20161130174802.GM18432@dhcp22.suse.cz> <20161130182552.GN18432@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16120216-0024-0000-0000-0000152D1460 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006180; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000193; SDB=6.00788388; UDB=6.00381471; IPR=6.00566063; 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 16:44:08 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16120216-0025-0000-0000-000046A2CE9B Message-Id: <20161202164408.GM3924@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-1612020256 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. And thank you again for all the testing!!! Thanx, Paul