From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f72.google.com (mail-lf0-f72.google.com [209.85.215.72]) by kanga.kvack.org (Postfix) with ESMTP id 47A106B0253 for ; Thu, 1 Dec 2016 13:10:06 -0500 (EST) Received: by mail-lf0-f72.google.com with SMTP id c13so99413606lfg.4 for ; Thu, 01 Dec 2016 10:10:06 -0800 (PST) Received: from mail.setcomm.ru (mail.setcomm.ru. [2a00:1248:5004:5::3]) by mx.google.com with ESMTP id t11si591845lfi.50.2016.12.01.10.10.04 for ; Thu, 01 Dec 2016 10:10:04 -0800 (PST) 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> From: Boris Zhmurov Message-ID: Date: Thu, 1 Dec 2016 21:10:01 +0300 MIME-Version: 1.0 In-Reply-To: <20161130182552.GN18432@dhcp22.suse.cz> Content-Type: multipart/mixed; boundary="------------541DA7624281D19B58B355C0" Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: paulmck@linux.vnet.ibm.com, Paul Menzel , Donald Buczek , linux-mm@kvack.org, linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------541DA7624281D19B58B355C0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Michal Hocko 30/11/16 21:25: >>> Do I get it right that s@cond_resched_rcu_qs@cond_resched@ didn't help? >> >> I didn't try that. I've tried 4 patches from Paul's linux-rcu tree. >> I can try another portion of patches, no problem :) > > Replacing cond_resched_rcu_qs in shrink_node_memcg by cond_resched would > be really helpful to tell whether we are missing a real scheduling point > or whether something more serious is going on here. 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. -- Boris Zhmurov System/Network Administrator mailto: bb@kernelpanic.ru "wget http://kernelpanic.ru/bb_public_key.pgp -O - | gpg --import" --------------541DA7624281D19B58B355C0 Content-Type: text/x-patch; name="linux-4.8-mm-prevent-shrink_node_memcg-RCU-CPU-stall-warnings.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename*0="linux-4.8-mm-prevent-shrink_node_memcg-RCU-CPU-stall-warning"; filename*1="s.patch" --- a/mm/vmscan.c.orig 2016-11-30 21:52:58.314895320 +0300 +++ b/mm/vmscan.c 2016-11-30 21:53:29.502895320 +0300 @@ -2352,6 +2352,7 @@ nr_reclaimed += shrink_list(lru, nr_to_scan, lruvec, sc); } + cond_resched(); } if (nr_reclaimed < nr_to_reclaim || scan_adjusted) --------------541DA7624281D19B58B355C0-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org