From: Christoph Hellwig <hch@infradead.org>
To: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Christoph Hellwig <hch@infradead.org>, Tejun Heo <tj@kernel.org>,
Stefan Priebe <s.priebe@profihost.ag>,
xfs@oss.sgi.com
Subject: Re: [PATCH 3/4] xfs: revert to using a kthread for AIL pushing
Date: Mon, 10 Oct 2011 09:26:11 -0400 [thread overview]
Message-ID: <20111010132611.GA1248@infradead.org> (raw)
In-Reply-To: <20111010055546.GA1641@x4.trippels.de>
On Mon, Oct 10, 2011 at 07:55:46AM +0200, Markus Trippelsdorf wrote:
> Wouldn't it be possible to verify that the problem also goes away with
> this simple one liner?
We've been through a few variants, and none fixed it while Stefan had
to try them on production machines.
To be honest I'm not convinced at all that a workqueue was such a good
idea for the ail in particular. It works extremly well for things were
we can easily define a work item, e.g. an object that gets queued up
and a method on it gets exectured. But for the AIL we really have
a changing target that needs more or less constant pushing, and the
target keeps changing while executing our work. Conceptually it fits
the idea of an thread much better, with the added benefit of not relying
on finding a combination of workqueue flags that gets the exact
behaviour (exectuion ASAP without any limits because of other items
or required memory allocation).
And unlike the various per-cpu threads we used to have it is only one
thread per filesystem anyway.
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next prev parent reply other threads:[~2011-10-10 13:26 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-06 18:32 [PATCH 0/4] fix AIL pushing under heavy concurrent metadata loads Christoph Hellwig
2011-10-06 18:32 ` [PATCH 1/4] xfs: do not update xa_last_pushed_lsn for locked items Christoph Hellwig
2011-10-07 22:18 ` Alex Elder
2011-10-10 1:37 ` Dave Chinner
2011-10-06 18:32 ` [PATCH 2/4] xfs: force the log if we encounter pinned buffers in .iop_pushbuf Christoph Hellwig
2011-10-07 22:18 ` Alex Elder
2011-10-10 1:39 ` Dave Chinner
2011-10-06 18:33 ` [PATCH 3/4] xfs: revert to using a kthread for AIL pushing Christoph Hellwig
2011-10-07 22:18 ` Alex Elder
2011-10-10 1:45 ` Dave Chinner
2011-10-10 5:55 ` Markus Trippelsdorf
2011-10-10 6:06 ` Stefan Priebe - Profihost AG
2011-10-10 13:26 ` Christoph Hellwig [this message]
2011-10-10 18:37 ` Tejun Heo
2011-10-19 11:16 ` Stefan Priebe - Profihost AG
2011-10-19 11:34 ` Christoph Hellwig
2011-10-19 13:10 ` Stefan Priebe - Profihost AG
2011-10-06 18:33 ` [PATCH 4/4] xfs: add AIL pushing tracepoints Christoph Hellwig
2011-10-07 22:18 ` Alex Elder
2011-10-10 1:45 ` Dave Chinner
-- strict thread matches above, loose matches on Subject: below --
2011-10-11 15:14 [PATCH 0/4] fix AIL pushing under heavy concurrent metadata loads V2 Christoph Hellwig
2011-10-11 15:14 ` [PATCH 3/4] xfs: revert to using a kthread for AIL pushing Christoph Hellwig
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