From: Dave Chinner <david@fromorbit.com>
To: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>,
Andreas Dilger <adilger@dilger.ca>, Jens Axboe <axboe@kernel.dk>,
linux-kernel <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Mingming Cao <mcao@us.ibm.com>,
linux-scsi <linux-scsi@vger.kernel.org>
Subject: Re: [RFC] block integrity: Fix write after checksum calculation problem
Date: Thu, 24 Feb 2011 10:47:50 +1100 [thread overview]
Message-ID: <20110223234750.GM3166@dastard> (raw)
In-Reply-To: <yq1vd0awwfh.fsf@sermon.lab.mkp.net>
On Wed, Feb 23, 2011 at 11:24:50AM -0500, Martin K. Petersen wrote:
> >>>>> "Dave" == Dave Chinner <david@fromorbit.com> writes:
>
> >> Agreed. I too am curious to study which circumstances favor copying
> >> vs blocking.
>
> Dave> IMO blocking is generally preferable in high throughput threaded
> Dave> workloads as there is always another thread that can do useful
> Dave> work while we wait for IO to complete. Most use cases for DIF
> Dave> center around high throughput environments....
>
> Yeah.
>
> A while back I did a bunch of tests with a liberal amount of
> wait_on_page_writeback() calls added to (I think) ext2, ext3, and
> XFS. For my regular workloads there was no measurable change (kernel
> builds, random database and I/O tests). I'm sure we'll unearth some apps
> that will suffer when DI is on but so far I'm not too worried about
> blocking in the data path.
>
> My main concern is wrt. metadata because that's where extN really
> hurts. Simple test: Unpack a kernel tarball and watch the directory
> block fireworks. Given how frequently those buffers get hit I'm sure
> blocking would cause performance to tank completely. I looked into
> fixing this in ext2 but I had to stop because my eyes were bleeding.
Not problems with metadata modifications for XFS - all metadata IO
is done with a lock held preventing modifications while IO is in
progress.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2011-02-23 23:47 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-22 2:00 [RFC] block integrity: Fix write after checksum calculation problem Darrick J. Wong
2011-02-22 5:45 ` Boaz Harrosh
2011-02-22 11:42 ` Jan Kara
2011-02-22 13:02 ` Chris Mason
2011-02-22 19:13 ` Boaz Harrosh
2011-03-04 20:51 ` Darrick J. Wong
2011-03-04 20:53 ` Christoph Hellwig
2011-02-22 16:13 ` Andreas Dilger
2011-02-22 16:40 ` Martin K. Petersen
2011-02-22 19:45 ` Darrick J. Wong
2011-02-22 22:53 ` Dave Chinner
2011-02-23 16:24 ` Martin K. Petersen
2011-02-23 23:47 ` Dave Chinner [this message]
2011-02-24 16:43 ` Jan Kara
2011-02-28 8:49 ` Christoph Hellwig
2011-02-22 16:45 ` Martin K. Petersen
2011-02-23 20:24 ` Joel Becker
2011-02-23 20:35 ` Chris Mason
2011-02-23 21:42 ` Joel Becker
2011-02-24 16:47 ` Jan Kara
2011-02-24 17:37 ` Chris Mason
2011-02-24 18:27 ` Darrick J. Wong
2011-02-28 12:54 ` Chris Mason
2011-03-04 21:07 ` Darrick J. Wong
2011-03-04 22:22 ` Andreas Dilger
2011-03-07 19:11 ` Darrick J. Wong
2011-03-07 21:12 ` Chris Mason
2011-03-08 4:56 ` Dave Chinner
2011-03-10 23:57 ` Darrick J. Wong
2011-03-11 16:34 ` Chris Mason
2011-03-11 18:51 ` Darrick J. Wong
2011-03-19 0:07 ` Darrick J. Wong
2011-03-19 2:28 ` Andreas Dilger
2011-03-22 19:23 ` Darrick J. Wong
2011-03-22 21:54 ` Jan Kara
2011-03-21 14:04 ` Jan Kara
2011-03-21 14:24 ` Chris Mason
2011-03-21 16:43 ` Jan Kara
2011-04-06 23:29 ` Darrick J. Wong
2011-04-07 16:44 ` Darrick J. Wong
2011-04-07 16:57 ` Jan Kara
2011-04-08 20:31 ` Darrick J. Wong
2011-04-11 16:42 ` Jeff Layton
2011-04-11 17:41 ` Chris Mason
2011-04-11 18:25 ` Christoph Hellwig
2011-04-11 18:38 ` Chris Mason
2011-04-12 0:46 ` Mingming Cao
2011-04-12 0:57 ` Christoph Hellwig
2011-04-14 0:48 ` Mingming Cao
2011-04-22 0:02 ` [RFC v2] block integrity: Stabilize(?) pages during writeback Darrick J. Wong
2011-04-22 12:50 ` Chris Mason
2011-04-22 20:34 ` Jan Kara
2011-04-26 0:37 ` Darrick J. Wong
2011-04-26 11:33 ` Chris Mason
2011-05-03 1:59 ` Darrick J. Wong
2011-05-04 1:26 ` Darrick J. Wong
2011-04-26 11:37 ` Jan Kara
2011-05-04 17:37 ` [PATCH v3 0/3] data integrity: Stabilize pages during writeback for ext4 Darrick J. Wong
2011-05-04 18:46 ` Christoph Hellwig
2011-05-04 19:21 ` Chris Mason
2011-05-04 20:00 ` Darrick J. Wong
2011-05-04 23:57 ` Darrick J. Wong
2011-05-05 15:26 ` Jan Kara
2011-05-04 17:39 ` [PATCH v3 1/3] ext4: Clean up some wait_on_page_writeback calls Darrick J. Wong
2011-05-04 17:41 ` [PATCH v3 2/3] ext4: Wait for writeback to complete while making pages writable Darrick J. Wong
2011-05-04 17:42 ` [PATCH v3 3/3] mm: Wait for writeback when grabbing pages to begin a write Darrick J. Wong
2011-05-04 18:48 ` Christoph Hellwig
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