From: Christoph Hellwig <hch@infradead.org>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>, xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: Do background CIL flushes via a workqueue
Date: Tue, 27 Mar 2012 12:03:00 -0400 [thread overview]
Message-ID: <20120327160300.GA22555@infradead.org> (raw)
In-Reply-To: <20120327155759.GB28707@redhat.com>
On Tue, Mar 27, 2012 at 11:57:59AM -0400, Vivek Goyal wrote:
> On Tue, Mar 27, 2012 at 10:31:27AM -0400, Christoph Hellwig wrote:
> > Vivek, does CFQ still need any hints for this sort of handoff?
> >
>
> Christoph, I don't understand the issue enough to comment on it.
>
> Had a quick look at the patch. Looks like some action (writing log), has
> been moved to a worker thread. And in some cases (log force triggered
> flush, whatever it is), we seem to prefer to do it from the submitter's
> context.
Yes. This is to workaround the old problem of cfq getting utterly
confused if cooperating I/O beeing submitted from different threads.
The case in the previous version of this patch was:
- thread doing the fsync will write out data, and wait for it
- then we'd force the log by kicking a workqueue and waiting for it
quite similar to the ext3/4 fsync issues that we had long discussions
about.
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next prev parent reply other threads:[~2012-03-27 16:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-27 9:46 [PATCH] xfs: Do background CIL flushes via a workqueue Dave Chinner
2012-03-27 14:31 ` Christoph Hellwig
2012-03-27 15:57 ` Vivek Goyal
2012-03-27 16:03 ` Christoph Hellwig [this message]
2012-03-27 16:19 ` Vivek Goyal
2012-03-27 17:03 ` Christoph Hellwig
2012-03-27 17:18 ` Vivek Goyal
2012-03-27 17:23 ` Vivek Goyal
2012-03-29 8:52 ` Dave Chinner
2012-03-29 8:51 ` Dave Chinner
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