From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>, xfs@oss.sgi.com
Subject: Re: [regression] stack overflow in xfs_buf_iodone_callbacks
Date: Mon, 25 Jun 2012 05:06:58 -0400 [thread overview]
Message-ID: <20120625090657.GA22726@infradead.org> (raw)
In-Reply-To: <20120622233955.GY19223@dastard>
On Sat, Jun 23, 2012 at 09:39:55AM +1000, Dave Chinner wrote:
> Hmmmm. How often do we get real io completion occurring before we
> call _xfs_buf_ioend() here? I can't see that it is common, so this
> is probably fine, but perhaps a few numbers might help here? If it
> is rare as we think it is, then yeah, that would work....
The only case where I can see it ever hapen is when sending tons
of separate I/Os in one go to a reall fast device, e.g. a very
fragmented large directory to superfast battery backed dram device.
And even then I don't think it matters very much - for reads we
generally do not have an b_iodone handler attached, so for these
the change does not make any different. For delayed writes the
additional context switch also doesn't have a major impact on
performance, so the only thing where we could see a difference
is synchronous writes, of which we don't have a lot left, and
essentially none unless the shrinkers kick in and need to do
synchronous reclaims.
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next prev parent reply other threads:[~2012-06-25 9:07 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-21 9:18 [regression] stack overflow in xfs_buf_iodone_callbacks Dave Chinner
2012-06-21 9:21 ` Christoph Hellwig
2012-06-21 9:29 ` Dave Chinner
2012-06-21 10:06 ` Stan Hoeppner
2012-06-21 16:34 ` Christoph Hellwig
2012-06-21 23:24 ` Dave Chinner
2012-06-22 16:41 ` Christoph Hellwig
2012-06-22 23:39 ` Dave Chinner
2012-06-25 9:06 ` Christoph Hellwig [this message]
2012-06-26 2:20 ` Dave Chinner
2012-06-26 7:51 ` Christoph Hellwig
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