From: Matthew Wilcox <matthew@wil.cx>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>,
linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org,
linux-kernel@vger.kernel.org, liml@rtr.ca, jens.axboe@oracle.com,
Matthew Wilcox <willy@linux.intel.com>
Subject: Re: [PATCH 1/7] Make DISCARD_BARRIER and DISCARD_NOBARRIER writes instead of reads
Date: Thu, 3 Sep 2009 11:56:18 -0600 [thread overview]
Message-ID: <20090903175617.GA26346@parisc-linux.org> (raw)
In-Reply-To: <1252000340.4483.529.camel@macbook.infradead.org>
On Thu, Sep 03, 2009 at 06:52:20PM +0100, David Woodhouse wrote:
> On Sat, 2009-08-29 at 19:03 -0400, Christoph Hellwig wrote:
> >
> > The commands are conceptually writes, and in the case of IDE and SCSI
> > commands actually are writes. They were only reads because we thought
> > that would interact better with the elevators. Now the elevators know
> > about discard requests, that advantage no longer exists.
>
> Can you drop the final sentence of that? It isn't true, and I never said
> it.
No, but you wouldn't give me a changelog entry, so I had to make
something up.
> s/. Now.*/, but that isn't necessary, and making them writes makes it
> easier for the low-level IDE and SCSI code to cope with the fact that
> the command has to be sent with a payload./
Thanks.
--
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:[~2009-09-03 17:56 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-29 23:03 [PATCH 0/7] discard support revisited Christoph Hellwig
2009-08-29 23:03 ` [PATCH 1/7] Make DISCARD_BARRIER and DISCARD_NOBARRIER writes instead of reads Christoph Hellwig
2009-09-03 17:52 ` David Woodhouse
2009-09-03 17:56 ` Matthew Wilcox [this message]
2009-08-29 23:03 ` [PATCH 2/7] block: use blkdev_issue_discard in blk_ioctl_discard Christoph Hellwig
2009-09-01 9:06 ` Steven Whitehouse
2009-09-11 22:26 ` Christoph Hellwig
2009-09-14 9:40 ` Jens Axboe
2009-08-29 23:03 ` [PATCH 3/7] block: discard may need to allocate pages Christoph Hellwig
2009-08-29 23:03 ` [PATCH 4/7] sd: add support for WRITE SAME (16) with unmap bit Christoph Hellwig
2009-08-30 0:43 ` Douglas Gilbert
2009-08-30 1:05 ` Christoph Hellwig
2009-08-30 2:43 ` Douglas Gilbert
2009-08-30 2:48 ` Christoph Hellwig
2009-08-30 11:12 ` Sergei Shtylyov
2009-08-30 17:14 ` Christoph Hellwig
2009-08-29 23:03 ` [PATCH 5/7] libata: Add support for TRIM Christoph Hellwig
2009-08-29 23:03 ` [PATCH 6/7] block: allow large discard requests Christoph Hellwig
2009-08-30 2:49 ` Mark Lord
2009-08-30 2:50 ` Matthew Wilcox
2009-08-30 2:52 ` Mark Lord
2009-08-30 2:56 ` Christoph Hellwig
2009-08-29 23:03 ` [PATCH 7/7] xfs: add batches discard support Christoph Hellwig
2009-08-29 23:37 ` [PATCH 0/7] discard support revisited Matthew Wilcox
2009-08-30 2:15 ` Christoph Hellwig
2009-08-30 3:03 ` Matthew Wilcox
2009-08-30 20:17 ` James Bottomley
2009-08-30 21:42 ` Matthew Wilcox
2009-08-30 22:48 ` Christoph Hellwig
2009-09-02 19:46 ` Matthew Wilcox
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