From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [regression] stack overflow in xfs_buf_iodone_callbacks
Date: Tue, 26 Jun 2012 12:20:11 +1000 [thread overview]
Message-ID: <20120626022011.GB19223@dastard> (raw)
In-Reply-To: <20120625090657.GA22726@infradead.org>
On Mon, Jun 25, 2012 at 05:06:58AM -0400, Christoph Hellwig wrote:
> 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.
We will very soon - CRC checks after reading for disk will be done
after reads. The patch series I'm working on at the moment
introduces sanity checks of buffers on read completion - it doesn't
do CRC checks yet, but it moves all the checks we do on read
completion into iodone callbacks, and when CRCs are introduced they
will simply be slotted into those functions....
> 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.
*nod*
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2012-06-26 2:20 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
2012-06-26 2:20 ` Dave Chinner [this message]
2012-06-26 7:51 ` Christoph Hellwig
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120626022011.GB19223@dastard \
--to=david@fromorbit.com \
--cc=hch@infradead.org \
--cc=xfs@oss.sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.