From: Dave Chinner <david@fromorbit.com>
To: Tejun Heo <tj@kernel.org>
Cc: Jan Kara <jack@suse.cz>,
axboe@kernel.dk, laijs@cn.fujitsu.com, fengguang.wu@intel.com,
linux-kernel@vger.kernel.org, jmoyer@redhat.com
Subject: Re: [PATCH 3/4] writeback: replace custom worker pool implementation with unbound workqueue
Date: Thu, 21 Mar 2013 12:57:21 +1100 [thread overview]
Message-ID: <20130321015721.GL17758@dastard> (raw)
In-Reply-To: <CAOS58YMop8+TnCGK2+SH52WNyK011vP0BWu3XENjrGt9xks32w@mail.gmail.com>
On Tue, Mar 19, 2013 at 10:28:24AM -0700, Tejun Heo wrote:
> Hello, Jan.
>
> On Tue, Mar 19, 2013 at 8:46 AM, Jan Kara <jack@suse.cz> wrote:
> > Well, but what you often get is just output of sysrq-w, or sysrq-t, or
> > splat from scheduler about stuck task. You often don't have the comfort of
> > tracing... Can't we somehow change 'comm' of the task when it starts
> > processing work of some bdi?
>
> You sure can but I'd prefer not to do that. If you wanna do it
> properly, you have to grab task lock every time a work item starts
> execution. I'm not sure how beneficial having the block device
> identifier would be. Backtrace would be there the same. Is identifying
> the block device that important?
When you have a system that has 50+ active filesystems (pretty
common in the distributed storage environments were every disk has
it's own filesystem), knowing which filesystem(s) are getting stuck
in writeback from the sysrq-w or hangcheck output is pretty damn
important....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2013-03-21 1:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-07 21:44 [PATCHSET] writeback: convert writeback to unbound workqueue Tejun Heo
2013-03-07 21:44 ` [PATCH 1/4] implement current_is_workqueue_rescuer() Tejun Heo
2013-03-13 0:42 ` Tejun Heo
2013-03-07 21:44 ` [PATCH 2/4] writeback: remove unused bdi_pending_list Tejun Heo
2013-03-12 12:02 ` Jan Kara
2013-03-07 21:44 ` [PATCH 3/4] writeback: replace custom worker pool implementation with unbound workqueue Tejun Heo
2013-03-12 15:05 ` Jan Kara
2013-03-18 22:32 ` Jan Kara
2013-03-18 22:35 ` Tejun Heo
2013-03-19 15:46 ` Jan Kara
2013-03-19 17:28 ` Tejun Heo
2013-03-21 1:57 ` Dave Chinner [this message]
2013-03-21 5:07 ` Tejun Heo
2013-03-21 11:32 ` Jan Kara
2013-03-21 13:08 ` Christoph Hellwig
2013-03-21 18:37 ` Tejun Heo
2013-03-07 21:44 ` [PATCH 4/4] writeback: expose the bdi_wq workqueue Tejun Heo
2013-03-12 15:06 ` [PATCHSET] writeback: convert writeback to unbound workqueue Jens Axboe
2013-03-12 17:10 ` Tejun Heo
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