From: Matthew Wilcox <matthew@wil.cx>
To: Mingming Cao <cmm@us.ibm.com>
Cc: Dave Chinner <david@fromorbit.com>,
Ric Wheeler <rwheeler@redhat.com>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
lsf@lists.linux-foundation.org,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
device-mapper development <dm-devel@redhat.com>
Subject: Re: [Lsf] Preliminary Agenda and Activities for LSF
Date: Wed, 30 Mar 2011 18:05:08 -0600 [thread overview]
Message-ID: <20110331000508.GV13806@parisc-linux.org> (raw)
In-Reply-To: <1301521798.7449.65.camel@mingming-laptop>
On Wed, Mar 30, 2011 at 02:49:58PM -0700, Mingming Cao wrote:
> > Direct IO semantics have always been that the application is allowed
> > to overlap IO to the same range if it wants to. The result is
> > undefined (just like issuing overlapping reads and writes to a disk
> > at the same time) so it's the application's responsibility to avoid
> > overlapping IO if it is a problem.
>
> I was thinking along the line to provide finer granularity lock to allow
> concurrent direct IO to different offset/range, but to same offset, they
> have to be serialized. If it's undefined behavior, i.e. overlapping is
> allowed, then concurrent dio implementation is much easier. But not sure
> if any apps currently using DIO aware of the ordering has to be done at
> the application level.
Yes, they're aware of it. And they consider it a bug if they ever do
concurrent I/O to the same sector.
--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
next prev parent reply other threads:[~2011-03-31 0:05 UTC|newest]
Thread overview: 138+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1301373398.2590.20.camel@mulgrave.site>
2011-03-29 5:14 ` [Lsf] Preliminary Agenda and Activities for LSF Amir Goldstein
2011-03-29 11:16 ` Ric Wheeler
2011-03-29 11:22 ` Matthew Wilcox
2011-03-29 12:17 ` Jens Axboe
2011-03-29 13:09 ` Martin K. Petersen
2011-03-29 13:12 ` Ric Wheeler
2011-03-29 13:38 ` James Bottomley
2011-03-29 17:20 ` Shyam_Iyer
2011-03-29 17:33 ` Vivek Goyal
2011-03-29 18:10 ` Shyam_Iyer
2011-03-29 18:45 ` Vivek Goyal
2011-03-29 19:13 ` Shyam_Iyer
2011-03-29 19:57 ` Vivek Goyal
2011-03-29 19:59 ` Mike Snitzer
2011-03-29 20:12 ` Shyam_Iyer
2011-03-29 20:23 ` Mike Snitzer
2011-03-29 23:09 ` Shyam_Iyer
2011-03-30 5:58 ` [Lsf] " Hannes Reinecke
2011-03-30 14:02 ` James Bottomley
2011-03-30 14:10 ` Hannes Reinecke
2011-03-30 14:26 ` James Bottomley
2011-03-30 14:55 ` Hannes Reinecke
2011-03-30 15:33 ` James Bottomley
2011-03-30 15:46 ` Shyam_Iyer
2011-03-30 20:32 ` Giridhar Malavali
2011-03-30 20:45 ` James Bottomley
2011-03-29 19:47 ` Nicholas A. Bellinger
2011-03-29 20:29 ` Jan Kara
2011-03-29 20:31 ` Ric Wheeler
2011-03-30 0:33 ` Mingming Cao
2011-03-30 2:17 ` Dave Chinner
2011-03-30 11:13 ` Theodore Tso
2011-03-30 11:28 ` Ric Wheeler
2011-03-30 14:07 ` Chris Mason
2011-04-01 15:19 ` Ted Ts'o
2011-04-01 16:30 ` Amir Goldstein
2011-04-01 21:46 ` Joel Becker
2011-04-02 3:26 ` Amir Goldstein
2011-04-01 21:43 ` Joel Becker
2011-03-30 21:49 ` Mingming Cao
2011-03-31 0:05 ` Matthew Wilcox [this message]
2011-03-31 1:00 ` Joel Becker
2011-04-01 21:34 ` Mingming Cao
2011-04-01 21:49 ` Joel Becker
2011-03-29 17:35 ` Chad Talbott
2011-03-29 19:09 ` Vivek Goyal
2011-03-29 20:14 ` Chad Talbott
2011-03-29 20:35 ` Jan Kara
2011-03-29 21:08 ` Greg Thelen
2011-03-30 4:18 ` Dave Chinner
2011-03-30 15:37 ` IO less throttling and cgroup aware writeback (Was: Re: [Lsf] Preliminary Agenda and Activities for LSF) Vivek Goyal
2011-03-30 22:20 ` Dave Chinner
2011-03-30 22:49 ` Chad Talbott
2011-03-31 3:00 ` Dave Chinner
2011-03-31 14:16 ` Vivek Goyal
2011-03-31 14:34 ` Chris Mason
2011-03-31 22:14 ` Dave Chinner
2011-03-31 23:43 ` Chris Mason
2011-04-01 0:55 ` Dave Chinner
2011-04-01 1:34 ` Vivek Goyal
2011-04-01 4:36 ` Dave Chinner
2011-04-01 6:32 ` [Lsf] IO less throttling and cgroup aware writeback (Was: " Christoph Hellwig
2011-04-01 7:23 ` Dave Chinner
2011-04-01 12:56 ` Christoph Hellwig
2011-04-21 15:07 ` Vivek Goyal
2011-04-01 14:49 ` IO less throttling and cgroup aware writeback (Was: Re: [Lsf] " Vivek Goyal
2011-03-31 22:25 ` Vivek Goyal
2011-03-31 14:50 ` [Lsf] IO less throttling and cgroup aware writeback (Was: " Greg Thelen
2011-03-31 22:27 ` Dave Chinner
2011-04-01 17:18 ` Vivek Goyal
2011-04-01 21:49 ` Dave Chinner
2011-04-02 7:33 ` Greg Thelen
2011-04-02 7:34 ` Greg Thelen
2011-04-05 13:13 ` Vivek Goyal
2011-04-05 22:56 ` Dave Chinner
2011-04-06 14:49 ` Curt Wohlgemuth
2011-04-06 15:39 ` Vivek Goyal
2011-04-06 19:49 ` Greg Thelen
2011-04-06 23:07 ` [Lsf] IO less throttling and cgroup aware writeback Greg Thelen
2011-04-06 23:36 ` Dave Chinner
2011-04-07 19:24 ` Vivek Goyal
2011-04-07 20:33 ` Christoph Hellwig
2011-04-07 21:34 ` Vivek Goyal
2011-04-07 23:42 ` Dave Chinner
2011-04-08 0:59 ` Greg Thelen
2011-04-08 1:25 ` Dave Chinner
2011-04-12 3:17 ` KAMEZAWA Hiroyuki
2011-04-08 13:43 ` Vivek Goyal
2011-04-06 23:08 ` [Lsf] IO less throttling and cgroup aware writeback (Was: Re: Preliminary Agenda and Activities for LSF) Dave Chinner
2011-04-07 20:04 ` Vivek Goyal
2011-04-07 23:47 ` Dave Chinner
2011-04-08 13:50 ` Vivek Goyal
2011-04-11 1:05 ` Dave Chinner
2011-04-06 15:37 ` Vivek Goyal
2011-04-06 16:08 ` Vivek Goyal
2011-04-06 17:10 ` Jan Kara
2011-04-06 17:14 ` Curt Wohlgemuth
2011-04-08 1:58 ` Dave Chinner
2011-04-19 14:26 ` Wu Fengguang
2011-04-06 23:50 ` Dave Chinner
2011-04-07 17:55 ` Vivek Goyal
2011-04-11 1:36 ` Dave Chinner
2011-04-15 21:07 ` Vivek Goyal
2011-04-16 3:06 ` Vivek Goyal
2011-04-18 21:58 ` Jan Kara
2011-04-18 22:51 ` cgroup IO throttling and filesystem ordered mode (Was: Re: [Lsf] IO less throttling and cgroup aware writeback (Was: Re: Preliminary Agenda and Activities for LSF)) Vivek Goyal
2011-04-19 0:33 ` Dave Chinner
2011-04-19 14:30 ` Vivek Goyal
2011-04-19 14:45 ` Jan Kara
2011-04-19 17:17 ` Vivek Goyal
2011-04-19 18:30 ` Vivek Goyal
2011-04-21 0:32 ` Dave Chinner
2011-04-21 0:29 ` Dave Chinner
2011-04-19 14:17 ` [Lsf] IO less throttling and cgroup aware writeback (Was: Re: Preliminary Agenda and Activities for LSF) Wu Fengguang
2011-04-19 14:34 ` Vivek Goyal
2011-04-19 14:48 ` Jan Kara
2011-04-19 15:11 ` Vivek Goyal
2011-04-19 15:22 ` Wu Fengguang
2011-04-19 15:31 ` Vivek Goyal
2011-04-19 16:58 ` Wu Fengguang
2011-04-19 17:05 ` Vivek Goyal
2011-04-19 20:58 ` Jan Kara
2011-04-20 1:21 ` Wu Fengguang
2011-04-20 10:56 ` Jan Kara
2011-04-20 11:19 ` Wu Fengguang
2011-04-20 14:42 ` Jan Kara
2011-04-20 1:16 ` Wu Fengguang
2011-04-20 18:44 ` Vivek Goyal
2011-04-20 19:16 ` Jan Kara
2011-04-21 0:17 ` Dave Chinner
2011-04-21 15:06 ` Wu Fengguang
2011-04-21 15:10 ` Wu Fengguang
2011-04-21 17:20 ` Vivek Goyal
2011-04-22 4:21 ` Wu Fengguang
2011-04-22 15:25 ` Vivek Goyal
2011-04-22 16:28 ` Andrea Arcangeli
2011-04-25 18:19 ` Vivek Goyal
2011-04-26 14:37 ` Vivek Goyal
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