From: Waiman Long <waiman.long@hp.com>
To: Marc Dionne <marc.c.dionne@gmail.com>
Cc: linux-btrfs@vger.kernel.org, clm@fb.com, t-itoh@jp.fujitsu.com
Subject: Re: Lockups with btrfs on 3.16-rc1 - bisected
Date: Wed, 18 Jun 2014 18:17:35 -0400 [thread overview]
Message-ID: <53A20FFF.3010807@hp.com> (raw)
In-Reply-To: <CAB9dFdsyB40V2BGwdQKzSSz7YUWMh-C2AWdDNK=PMG9h+BO57w@mail.gmail.com>
On 06/18/2014 04:57 PM, Marc Dionne wrote:
> Hi,
>
> I've been seeing very reproducible soft lockups with 3.16-rc1 similar
> to what is reported here:
> http://marc.info/?l=linux-btrfs&m=140290088532203&w=2 , along with the
> occasional hard lockup, making it impossible to complete a parallel
> build on a btrfs filesystem for the package I work on. This was
> working fine just a few days before rc1.
>
> Bisecting brought me to the following commit:
>
> commit bd01ec1a13f9a327950c8e3080096446c7804753
> Author: Waiman Long<Waiman.Long@hp.com>
> Date: Mon Feb 3 13:18:57 2014 +0100
>
> x86, locking/rwlocks: Enable qrwlocks on x86
>
> And sure enough if I revert that commit on top of current mainline,
> I'm unable to reproduce the soft lockups and hangs.
>
> Marc
The queue rwlock is fair. As a result, recursive read_lock is not
allowed unless the task is in an interrupt context. Doing recursive
read_lock will hang the process when a write_lock happens somewhere in
between. Are recursive read_lock being done in the btrfs code?
-Longman
next prev parent reply other threads:[~2014-06-18 22:18 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-18 20:57 Lockups with btrfs on 3.16-rc1 - bisected Marc Dionne
2014-06-18 22:17 ` Waiman Long [this message]
2014-06-18 22:27 ` Josef Bacik
2014-06-18 22:47 ` Waiman Long
2014-06-18 23:10 ` Josef Bacik
2014-06-18 23:19 ` Waiman Long
2014-06-18 23:27 ` Chris Mason
2014-06-18 23:30 ` Waiman Long
2014-06-18 23:53 ` Chris Mason
2014-06-19 0:03 ` Marc Dionne
2014-06-19 0:08 ` Waiman Long
2014-06-19 0:41 ` Marc Dionne
2014-06-19 2:03 ` Marc Dionne
2014-06-19 2:11 ` Chris Mason
2014-06-19 3:21 ` Waiman Long
2014-06-19 16:51 ` Chris Mason
2014-06-19 17:52 ` Waiman Long
2014-06-19 20:10 ` Chris Mason
2014-06-19 21:50 ` Chris Mason
2014-06-19 23:21 ` Waiman Long
2014-06-20 3:20 ` Tsutomu Itoh
2014-06-21 1:09 ` Long, Wai Man
2014-06-19 9:49 ` btrfs-transacti:516 blocked 120 seconds on 3.16-rc1 Konstantinos Skarlatos
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