From: Christoph Hellwig <hch@lst.de>
To: Tejun Heo <tj@kernel.org>
Cc: Mike Snitzer <snitzer@redhat.com>,
jaxboe@fusionio.com, linux-fsdevel@vger.kernel.org,
linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
hch@lst.de, James.Bottomley@suse.de, tytso@mit.edu,
chris.mason@oracle.com, swhiteho@redhat.com,
konishi.ryusuke@lab.ntt.co.jp, dm-devel@redhat.com, vst@vlnb.net,
jack@suse.cz, rwheeler@redhat.com, hare@suse.de, neilb@suse.de,
rusty@rustcorp.com.au, mst@redhat.com, Tejun Heo <tj@kernle.org>
Subject: Re: [PATCH 5/5] dm: implement REQ_FLUSH/FUA support
Date: Tue, 17 Aug 2010 15:13:09 +0200 [thread overview]
Message-ID: <20100817131309.GA2963@lst.de> (raw)
In-Reply-To: <4C6A5780.2090100@kernel.org>
On Tue, Aug 17, 2010 at 11:33:52AM +0200, Tejun Heo wrote:
> > That logic wasn't just about retries (at least not in the latest
> > kernel). With commit 708e929513502fb0 the -EOPNOTSUPP checking also
> > serves to optimize the barrier+discard case (when discards aren't
> > supported).
>
> With the patch applied, there's no second flush. Those requests would
> now be REQ_FLUSH + REQ_DISCARD. The first can't be avoided anyway and
> there won't be the second flush to begin with, so I don't think this
> worsens anything.
In fact the pre-flush is completely superflous for discards, but that's a
separate discussion and should not be changed as part of this patchset but
rather explicitly.
next prev parent reply other threads:[~2010-08-17 13:13 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-16 16:51 [RFC PATCHSET block#for-2.6.36-post] block: convert to REQ_FLUSH/FUA Tejun Heo
2010-08-16 16:51 ` [PATCH 1/5] block/loop: implement REQ_FLUSH/FUA support Tejun Heo
2010-08-16 16:52 ` [PATCH 2/5] virtio_blk: " Tejun Heo
2010-08-16 18:33 ` Christoph Hellwig
2010-08-17 8:17 ` Tejun Heo
2010-08-17 13:23 ` Christoph Hellwig
2010-08-17 16:22 ` Tejun Heo
2010-08-18 10:22 ` Rusty Russell
2010-08-17 1:16 ` Rusty Russell
2010-08-17 8:18 ` Tejun Heo
2010-08-19 15:14 ` [PATCH 2/5 UPDATED] virtio_blk: drop REQ_HARDBARRIER support Tejun Heo
2010-08-16 16:52 ` [PATCH 3/5] lguest: replace VIRTIO_F_BARRIER support with VIRTIO_F_FLUSH/FUA support Tejun Heo
2010-08-19 15:15 ` [PATCH 3/5] lguest: replace VIRTIO_F_BARRIER support with VIRTIO_F_FLUSH support Tejun Heo
2010-08-16 16:52 ` [PATCH 4/5] md: implment REQ_FLUSH/FUA support Tejun Heo
2010-08-24 5:41 ` Neil Brown
2010-08-25 11:22 ` [PATCH UPDATED " Tejun Heo
2010-08-25 11:42 ` Neil Brown
2010-08-16 16:52 ` [PATCH 5/5] dm: implement " Tejun Heo
2010-08-16 19:02 ` Mike Snitzer
2010-08-17 9:33 ` Tejun Heo
2010-08-17 13:13 ` Christoph Hellwig [this message]
2010-08-17 14:07 ` Mike Snitzer
2010-08-17 16:51 ` Tejun Heo
2010-08-17 18:21 ` Mike Snitzer
2010-08-18 6:32 ` Tejun Heo
2010-08-19 10:32 ` Kiyoshi Ueda
2010-08-19 15:45 ` Tejun Heo
2010-08-18 9:53 ` [RFC PATCHSET block#for-2.6.36-post] block: convert to REQ_FLUSH/FUA Christoph Hellwig
2010-08-18 14:26 ` James Bottomley
2010-08-18 14:33 ` Christoph Hellwig
2010-08-19 15:37 ` FUJITA Tomonori
2010-08-19 15:41 ` Christoph Hellwig
2010-08-19 15:56 ` FUJITA Tomonori
2010-08-23 16:47 ` Christoph Hellwig
2010-08-24 9:51 ` Lars Ellenberg
2010-08-24 15:45 ` Philipp Reisner
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