From: Tejun Heo <tj@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: 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,
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
Subject: Re: [PATCH 2/5] virtio_blk: implement REQ_FLUSH/FUA support
Date: Tue, 17 Aug 2010 18:22:38 +0200 [thread overview]
Message-ID: <4C6AB74E.7080909@kernel.org> (raw)
In-Reply-To: <20100817132327.GA3347@lst.de>
Hello,
On 08/17/2010 03:23 PM, Christoph Hellwig wrote:
>> Hmmm... the underlying storage could be md/dm RAIDs in which case FUA
>> should be cheaper than FLUSH.
>
> If someone ever wrote a virtio-blk backend that sits directly ontop
> of the Linux block layer that would be true. Of the five known
> virtio-blk backends all operate on normal files using the Posix I/O
> APIs, or the Linux aio API (optionally in qemu) or in-kernel
> vfs_read/vfs_write (vhost-blk).
Right.
> Given how little testing lguest gets compared to qemu I really don't
> want a protocol addition for it unless it really buys us something.
> Once we're done with this barrier conversion I plan into benchmarking
> FUA and a pre-flush tag on the command for virtio in real life setups,
> and see if it actually buys us anything.
Hmmm... yeah, we can drop it. Michael, what do you think?
Thanks.
--
tejun
next prev parent reply other threads:[~2010-08-17 16:22 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 [this message]
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
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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