From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: "Darrick J. Wong" <djwong@kernel.org>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 4/3] xfs: set WQ_SYSFS on all workqueues in debug mode
Date: Thu, 28 Jan 2021 10:29:42 +1100 [thread overview]
Message-ID: <20210127232942.GM4662@dread.disaster.area> (raw)
In-Reply-To: <20210127170306.GC1730140@infradead.org>
On Wed, Jan 27, 2021 at 05:03:06PM +0000, Christoph Hellwig wrote:
> On Mon, Jan 25, 2021 at 09:06:19PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > When CONFIG_XFS_DEBUG=y, set WQ_SYSFS on all workqueues that we create
> > so that we (developers) have a means to monitor cpu affinity and whatnot
> > for background workers. In the next patchset we'll expose knobs for
> > some of the workqueues publicly and document it, but not now.
>
> I don't really think this is a very good idea. If we want something like
> this it should be kernel-wide and coordinated with the workqueue
> maintainer, but I'm a little doubtful about the use case.
I don't think it is particular useful kernel wide. If it was, the
maintainer wouldn't have introduced a per-workqueue flag for this
functionality.
The reality is that very few workqueues in the system can expand out
into running thousands of kworker threads like the XFS workqueues
often do. And, really, there's nothing useful a typical user can do
at this point with the workqueue knobs to "tune" the behaviour - the
visibility/control the workqueue sysfs knobs provide at this point
is really only useful to XFS developers running tests in controlled
conditions...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
prev parent reply other threads:[~2021-01-27 23:31 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-23 18:53 [PATCHSET 0/3] xfs: speed up parallel workqueues Darrick J. Wong
2021-01-23 18:53 ` [PATCH 1/3] xfs: increase the default parallelism levels of pwork clients Darrick J. Wong
2021-01-24 9:57 ` Christoph Hellwig
2021-01-25 23:07 ` Darrick J. Wong
2021-01-26 5:04 ` [PATCH v2.1 " Darrick J. Wong
2021-01-26 20:46 ` Dave Chinner
2021-01-26 23:32 ` Darrick J. Wong
2021-01-23 18:53 ` [PATCH 2/3] xfs: use unbounded workqueues for parallel work Darrick J. Wong
2021-01-24 9:51 ` Christoph Hellwig
2021-01-25 23:18 ` Darrick J. Wong
2021-01-23 18:53 ` [PATCH 3/3] xfs: set WQ_SYSFS on all workqueues Darrick J. Wong
2021-01-24 9:54 ` Christoph Hellwig
2021-01-25 23:30 ` Darrick J. Wong
2021-01-26 5:06 ` [PATCH 4/3] xfs: set WQ_SYSFS on all workqueues in debug mode Darrick J. Wong
2021-01-26 20:48 ` Dave Chinner
2021-01-27 17:03 ` Christoph Hellwig
2021-01-27 23:29 ` Dave Chinner [this message]
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