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From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@us.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>, "Ted Ts'o" <tytso@mit.edu>,
	Mingming Cao <cmm@us.ibm.com>, Ric Wheeler <rwheeler@redhat.com>,
	linux-ext4 <linux-ext4@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Keith Mannthey <kmannth@us.ibm.com>,
	Mingming Cao <mcao@us.ibm.com>, Tejun Heo <tj@kernel.org>
Subject: Re: [RFC v3] ext4: Combine barrier requests coming from fsync
Date: Thu, 19 Aug 2010 04:53:49 -0400	[thread overview]
Message-ID: <20100819085349.GA8782@infradead.org> (raw)
In-Reply-To: <20100819020734.GL2109@tux1.beaverton.ibm.com>

On Wed, Aug 18, 2010 at 07:07:34PM -0700, Darrick J. Wong wrote:
> Oddly, I ran the entire suite of tests against a larger set of machines, and
> with Tejun's RFC patchset I didn't see nearly as much of an improvement.  I
> have been trying to put together a new tree based on "replace barrier with
> sequenced flush" and Christoph's "explicitly flush/FUA" patch sets, though I've
> gotten lost in the weeds. :(

Tejun's patches don't allow concurrent cache flushes to happen, while
my patch did.  Tejun said there are drivers that can't handly empty
flushes with a bio attached, making this nessecary.   

Tejun, any idea what drivers that would be?

> I also experienced some sort of crash with Tejun's relaxed barrier patch on one
> of my systems.  I was hitting the BUG_ON in drivers/scsi/scsi_lib.c, line 1115.

My kernel source doesn't have a BUG_ON line there, but only one two
lines above.  A req->nr_phys_segments that's zero sounds a bit like
empty flush requests, I'll need to look into it again.


  reply	other threads:[~2010-08-19  8:53 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-29 23:51 [RFC] ext4: Don't send extra barrier during fsync if there are no dirty pages Darrick J. Wong
2010-05-04  0:57 ` Mingming Cao
2010-05-04 14:16   ` Ric Wheeler
2010-05-04 15:45     ` Christoph Hellwig
2010-06-30 12:48       ` tytso
2010-06-30 13:21         ` Ric Wheeler
2010-06-30 13:44           ` tytso
2010-06-30 13:54             ` Ric Wheeler
2010-06-30 19:05               ` Andreas Dilger
2010-07-21 17:16             ` Jan Kara
2010-08-03  0:09               ` Darrick J. Wong
2010-08-03  9:01                 ` Christoph Hellwig
2010-08-04 18:16                   ` Darrick J. Wong
2010-08-03 13:21                 ` Jan Kara
2010-08-03 13:24         ` Avi Kivity
2010-08-04 23:32           ` Ted Ts'o
2010-08-05  2:20             ` Avi Kivity
2010-08-05 16:17               ` Ted Ts'o
2010-08-05 19:13                 ` Jeff Moyer
2010-08-05 20:39                   ` Ted Ts'o
2010-08-05 20:44                     ` Jeff Moyer
2010-05-04 19:49     ` Mingming Cao
2010-06-29 20:51       ` [RFC v2] " Darrick J. Wong
2010-08-05 16:40         ` Ted Ts'o
2010-08-05 16:45           ` Ted Ts'o
2010-08-06  7:04             ` Darrick J. Wong
2010-08-06 10:17               ` Ric Wheeler
2010-08-09 19:53               ` [RFC v3] ext4: Combine barrier requests coming from fsync Darrick J. Wong
2010-08-09 21:07                 ` Christoph Hellwig
2010-08-16 16:14                   ` Darrick J. Wong
2010-08-19  2:07                     ` Darrick J. Wong
2010-08-19  8:53                       ` Christoph Hellwig [this message]
2010-08-19  9:17                         ` Tejun Heo
2010-08-19 15:48                           ` Tejun Heo
2010-08-09 21:19                 ` Andreas Dilger
2010-08-09 23:38                   ` Darrick J. Wong
2010-08-19  2:14                     ` [RFC v4] ext4: Coordinate fsync requests Darrick J. Wong
2010-08-23 18:31                       ` Performance testing of various barrier reduction patches [was: Re: [RFC v4] ext4: Coordinate fsync requests] Darrick J. Wong
2010-09-23 23:25                         ` Darrick J. Wong
2010-09-24  6:24                           ` Andreas Dilger
2010-09-24 11:44                             ` Ric Wheeler
2010-09-27 23:01                             ` Darrick J. Wong
2010-10-08 21:26                               ` Darrick J. Wong
2010-10-08 21:56                                 ` Ric Wheeler
2010-10-11 20:20                                   ` Darrick J. Wong
2010-10-12 14:14                                     ` Christoph Hellwig
2010-10-15 23:39                                       ` Darrick J. Wong
2010-10-15 23:40                                         ` Christoph Hellwig
2010-10-16  0:02                                           ` Darrick J. Wong
2010-10-11 14:33                                 ` Ted Ts'o
2010-10-18 22:49                                 ` Darrick J. Wong
2010-10-19 18:28                                   ` Christoph Hellwig
2010-08-06  7:13           ` [RFC v2] ext4: Don't send extra barrier during fsync if there are no dirty pages Darrick J. Wong
2010-08-06 18:04             ` Ted Ts'o
2010-08-09 19:36               ` Darrick J. Wong

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