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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."

  reply	other threads:[~2011-03-31  0:05 UTC|newest]

Thread overview: 166+ 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 13:09         ` 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 17:20     ` Shyam_Iyer
2011-03-29 17:33     ` Vivek Goyal
2011-03-29 18:10       ` Shyam_Iyer
2011-03-29 18:10         ` Shyam_Iyer
2011-03-29 18:45         ` Vivek Goyal
2011-03-29 19:13           ` Shyam_Iyer
2011-03-29 19:13             ` 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 20:12                 ` Shyam_Iyer
2011-03-29 20:23                 ` Mike Snitzer
2011-03-29 23:09                   ` Shyam_Iyer
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 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
2011-04-01 21:43             ` Joel Becker
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 15:35 ` [LSF][MM] page allocation & direct reclaim latency Rik van Riel
2011-03-29 19:05   ` [Lsf] " Andrea Arcangeli
2011-03-29 20:35     ` Ying Han
2011-03-29 20:39       ` Ying Han
2011-03-29 20:45       ` Andrea Arcangeli
2011-03-29 20:53         ` Ying Han
2011-03-29 21:22     ` Rik van Riel
2011-03-29 22:38       ` Andrea Arcangeli
2011-03-29 22:13     ` Minchan Kim
2011-03-29 23:12       ` Andrea Arcangeli
2011-03-30 16:17       ` Mel Gorman
2011-03-30 16:49         ` Andrea Arcangeli
2011-03-31  0:42           ` Hugh Dickins
2011-03-31 15:15             ` Andrea Arcangeli
2011-03-31  9:30           ` Mel Gorman
2011-03-31 16:36             ` Andrea Arcangeli
2011-03-30 16:59         ` Dan Magenheimer
2011-03-29 17:35 ` [Lsf] Preliminary Agenda and Activities for LSF 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 19:57                 ` [LSF]: fc_rport attributes to further populate HBAAPIv2 Giridhar Malavali
2011-04-01 21:49                 ` [Lsf] IO less throttling and cgroup aware writeback (Was: Re: Preliminary Agenda and Activities for LSF) 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
2011-04-08  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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