Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753006AbcLBQlT (ORCPT ); Fri, 2 Dec 2016 11:41:19 -0500 Received: from mail.setcomm.ru ([81.211.32.179]:10314 "EHLO mail.setcomm.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750833AbcLBQjs (ORCPT ); Fri, 2 Dec 2016 11:39:48 -0500 Reply-To: bb@kernelpanic.ru Subject: Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` References: <20161125212000.GI31360@linux.vnet.ibm.com> <20161128095825.GI14788@dhcp22.suse.cz> <20161128105425.GY31360@linux.vnet.ibm.com> <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> Cc: Michal Hocko , Paul Menzel , Donald Buczek , linux-mm@kvack.org, linux-kernel@vger.kernel.org To: paulmck@linux.vnet.ibm.com From: Boris Zhmurov X-Enigmail-Draft-Status: N1110 Message-ID: Date: Fri, 2 Dec 2016 19:39:24 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 944 Lines: 30 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. Thanks. -- Boris Zhmurov mailto: bb@kernelpanic.ru "wget http://kernelpanic.ru/bb_public_key.pgp -O - | gpg --import"