Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1753973AbcLBQo6 (ORCPT <rfc822;w@1wt.eu>);
        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
        <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 2 Dec 2016 11:44:31 -0500
Date: Fri, 2 Dec 2016 08:44:08 -0800
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Boris Zhmurov <bb@kernelpanic.ru>
Cc: Michal Hocko <mhocko@kernel.org>, Paul Menzel <pmenzel@molgen.mpg.de>,
        Donald Buczek <buczek@molgen.mpg.de>, 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>
 <eba1571e-f7a8-09b3-5516-c2bc35b38a83@kernelpanic.ru>
 <20161128150509.GG3924@linux.vnet.ibm.com>
 <66fd50e1-a922-846a-f427-7654795bd4b5@kernelpanic.ru>
 <20161130174802.GM18432@dhcp22.suse.cz>
 <fd34243c-2ebf-c14b-55e6-684a9dc614e7@kernelpanic.ru>
 <20161130182552.GN18432@dhcp22.suse.cz>
 <e50dcb85-4552-9249-c53e-017fefcaf80b@kernelpanic.ru>
 <a21ba936-0b8e-fd8e-620e-933850cc992d@kernelpanic.ru>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <a21ba936-0b8e-fd8e-620e-933850cc992d@kernelpanic.ru>
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: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1051
Lines: 30

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