From: Donald Buczek <buczek@molgen.mpg.de>
To: Michal Hocko <mhocko@kernel.org>
Cc: dvteam@molgen.mpg.de, Paul Menzel <pmenzel@molgen.mpg.de>,
linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
Josh Triplett <josh@joshtriplett.org>
Subject: Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node`
Date: Sun, 27 Nov 2016 10:19:06 +0100 [thread overview]
Message-ID: <583AA50A.9010608@molgen.mpg.de> (raw)
In-Reply-To: <20161124101525.GB20668@dhcp22.suse.cz>
On 24.11.2016 11:15, Michal Hocko wrote:
> On Mon 21-11-16 16:35:53, Donald Buczek wrote:
> [...]
>> Hello,
>>
>> thanks a lot for looking into this!
>>
>> Let me add some information from the reporting site:
>>
>> * We've tried the patch from Paul E. McKenney (the one posted Wed, 16 Nov
>> 2016) and it doesn't shut up the rcu stall warnings.
>>
>> * Log file from a boot with the patch applied ( grep kernel
>> /var/log/messages ) is here :
>> http://owww.molgen.mpg.de/~buczek/321322/2016-11-21_syslog.txt
>>
>> * This system is a backup server and walks over thousands of files sometimes
>> with multiple parallel rsync processes.
>>
>> * No rcu_* warnings on that machine with 4.7.2, but with 4.8.4 , 4.8.6 ,
>> 4.8.8 and now 4.9.0-rc5+Pauls patch
> I assume you haven't tried the Linus 4.8 kernel without any further
> stable patches? Just to be sure we are not talking about some later
> regression which found its way to the stable tree.
We've tried v4.8 and got the first rcu stall warnings with this, too.
First one after about 20 hours uptime.
>> * When the backups are actually happening there might be relevant memory
>> pressure from inode cache and the rsync processes. We saw the oom-killer
>> kick in on another machine with same hardware and similar (a bit higher)
>> workload. This other machine also shows a lot of rcu stall warnings since
>> 4.8.4.
>>
>> * We see "rcu_sched detected stalls" also on some other machines since we
>> switched to 4.8 but not as frequently as on the two backup servers. Usually
>> there's "shrink_node" and "kswapd" on the top of the stack. Often
>> "xfs_reclaim_inodes" variants on top of that.
> I would be interested to see some reclaim tracepoints enabled. Could you
> try that out? At least mm_shrink_slab_{start,end} and
> mm_vmscan_lru_shrink_inactive. This should tell us more about how the
> reclaim behaved.
http://owww.molgen.mpg.de/~buczek/321322/2016-11-26.dmesg.txt (80K)
http://owww.molgen.mpg.de/~buczek/321322/2016-11-26.trace.txt (50M)
Traces wrapped, but the last event is covered. all vmscan events were
enabled
--
Donald Buczek
buczek@molgen.mpg.de
Tel: +49 30 8413 1433
next prev parent reply other threads:[~2016-11-27 9:19 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <24c226a5-1a4a-173e-8b4e-5107a2baac04@molgen.mpg.de>
2016-11-08 12:22 ` INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Paul Menzel
2016-11-08 17:03 ` Paul E. McKenney
2016-11-08 17:38 ` Paul Menzel
2016-11-08 18:39 ` Paul E. McKenney
2016-11-16 17:01 ` Paul Menzel
2016-11-16 17:30 ` Paul E. McKenney
2016-11-21 13:41 ` Michal Hocko
2016-11-21 14:01 ` Paul E. McKenney
2016-11-21 14:18 ` Michal Hocko
2016-11-21 14:29 ` Paul E. McKenney
2016-11-21 15:35 ` Donald Buczek
2016-11-24 10:15 ` Michal Hocko
2016-11-24 18:50 ` Donald Buczek
2016-11-27 9:37 ` Paul Menzel
2016-11-27 5:32 ` Christopher S. Aker
2016-11-27 9:19 ` Donald Buczek [this message]
2016-11-28 11:04 ` Michal Hocko
2016-11-28 12:26 ` Paul Menzel
2016-11-30 10:28 ` Donald Buczek
2016-11-30 11:09 ` Michal Hocko
2016-11-30 11:43 ` Donald Buczek
2016-12-02 9:14 ` Donald Buczek
2016-12-06 8:32 ` Donald Buczek
2016-11-30 11:53 ` Paul E. McKenney
2016-11-30 11:54 ` Paul E. McKenney
2016-11-30 12:31 ` Paul Menzel
2016-11-30 14:31 ` Paul E. McKenney
2016-11-30 13:19 ` Michal Hocko
2016-11-30 14:29 ` Paul E. McKenney
2016-11-30 16:38 ` Peter Zijlstra
2016-11-30 17:02 ` Paul E. McKenney
2016-11-30 17:05 ` Michal Hocko
2016-11-30 17:23 ` Paul E. McKenney
2016-11-30 17:34 ` Michal Hocko
2016-11-30 17:50 ` Peter Zijlstra
2016-11-30 19:40 ` Paul E. McKenney
2016-12-01 5:30 ` Peter Zijlstra
2016-12-01 12:40 ` Paul E. McKenney
2016-12-01 16:36 ` Peter Zijlstra
2016-12-01 16:59 ` Paul E. McKenney
2016-12-01 18:09 ` Peter Zijlstra
2016-12-01 18:42 ` Paul E. McKenney
2016-12-01 18:49 ` Peter Zijlstra
[not found] <20161125212000.GI31360@linux.vnet.ibm.com>
[not found] ` <20161128095825.GI14788@dhcp22.suse.cz>
[not found] ` <20161128105425.GY31360@linux.vnet.ibm.com>
[not found] ` <3a4242cb-0198-0a3b-97ae-536fb5ff83ec@kernelpanic.ru>
[not found] ` <20161128143435.GC3924@linux.vnet.ibm.com>
[not found] ` <eba1571e-f7a8-09b3-5516-c2bc35b38a83@kernelpanic.ru>
[not found] ` <20161128150509.GG3924@linux.vnet.ibm.com>
[not found] ` <66fd50e1-a922-846a-f427-7654795bd4b5@kernelpanic.ru>
[not found] ` <20161130174802.GM18432@dhcp22.suse.cz>
[not found] ` <fd34243c-2ebf-c14b-55e6-684a9dc614e7@kernelpanic.ru>
[not found] ` <20161130182552.GN18432@dhcp22.suse.cz>
2016-12-01 18:10 ` Boris Zhmurov
2016-12-01 19:39 ` Paul E. McKenney
2016-12-02 9:37 ` Michal Hocko
2016-12-02 13:52 ` Paul E. McKenney
2016-12-02 16:39 ` Boris Zhmurov
2016-12-02 16:44 ` Paul E. McKenney
2016-12-02 17:02 ` Michal Hocko
2016-12-02 17:15 ` Paul E. McKenney
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