From: Kevin Wolf <kwolf@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations
Date: Fri, 09 Mar 2012 17:37:06 +0100 [thread overview]
Message-ID: <4F5A31B2.3050701@redhat.com> (raw)
In-Reply-To: <1331226917-6658-7-git-send-email-pbonzini@redhat.com>
Am 08.03.2012 18:15, schrieb Paolo Bonzini:
> Remove the bdrv_co_write_zeroes callback. Instead use the discard
> information from bdrv_get_info to choose between bdrv_co_discard
> and a normal write.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
I'm not sure if this a good idea.
The goal of discard is to remove data from the image (or not add it if
it isn't there yet) and ideally deallocate the used clusters. The goal
of write_zeroes is to mark space as zero and explicitly allocate it for
this purpose.
>From a guest point of view these are pretty similar, but from a host
perspective I'd say there's a difference.
Kevin
next prev parent reply other threads:[~2012-03-09 16:33 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-08 17:15 [Qemu-devel] [RFC PATCH 00/17] Improvements around discard and write zeroes Paolo Bonzini
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 01/17] qemu-iotests: add a simple test for write_zeroes Paolo Bonzini
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 02/17] qed: make write-zeroes bounce buffer smaller than a single cluster Paolo Bonzini
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 03/17] block: add discard properties to BlockDriverInfo Paolo Bonzini
2012-03-09 16:47 ` Kevin Wolf
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 04/17] qed: implement bdrv_aio_discard Paolo Bonzini
2012-03-09 16:31 ` Kevin Wolf
2012-03-09 17:53 ` Paolo Bonzini
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 05/17] block: pass around qiov for write_zeroes operation Paolo Bonzini
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 06/17] block: use bdrv_{co, aio}_discard for write_zeroes operations Paolo Bonzini
2012-03-09 16:37 ` Kevin Wolf [this message]
2012-03-09 18:06 ` Paolo Bonzini
2012-03-10 18:02 ` Richard Laager
2012-03-12 12:27 ` Paolo Bonzini
2012-03-12 13:04 ` Kevin Wolf
2012-03-13 19:13 ` Richard Laager
2012-03-14 7:41 ` Paolo Bonzini
2012-03-14 12:01 ` Kevin Wolf
2012-03-14 12:14 ` Paolo Bonzini
2012-03-14 12:37 ` Kevin Wolf
2012-03-14 12:49 ` Paolo Bonzini
2012-03-14 13:04 ` Kevin Wolf
2012-03-24 15:33 ` Christoph Hellwig
2012-03-24 15:30 ` Christoph Hellwig
2012-03-26 19:40 ` Richard Laager
2012-03-27 10:20 ` Kevin Wolf
2012-03-24 15:29 ` Christoph Hellwig
2012-03-26 9:44 ` Daniel P. Berrange
2012-03-26 9:56 ` Christoph Hellwig
2012-03-15 0:42 ` Richard Laager
2012-03-15 9:36 ` Paolo Bonzini
2012-03-16 0:47 ` Richard Laager
2012-03-16 9:34 ` Paolo Bonzini
2012-03-24 15:27 ` Christoph Hellwig
2012-03-26 19:40 ` Richard Laager
2012-03-27 9:08 ` Christoph Hellwig
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 07/17] block: make high level discard operation always zero Paolo Bonzini
2012-03-08 17:55 ` Avi Kivity
2012-03-09 16:42 ` Kevin Wolf
2012-03-12 10:42 ` Avi Kivity
2012-03-12 11:04 ` Kevin Wolf
2012-03-12 12:03 ` Avi Kivity
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 08/17] block: kill the write zeroes operation Paolo Bonzini
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 09/17] ide: issue discard asynchronously but serialize the pieces Paolo Bonzini
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 10/17] ide/scsi: add discard_zeroes_data property Paolo Bonzini
2012-03-08 18:13 ` Avi Kivity
2012-03-08 18:14 ` Avi Kivity
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 11/17] ide/scsi: prepare for flipping the discard defaults Paolo Bonzini
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 12/17] ide/scsi: turn on discard Paolo Bonzini
2012-03-08 18:17 ` Avi Kivity
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 13/17] block: fallback from discard to writes Paolo Bonzini
2012-03-24 15:35 ` Christoph Hellwig
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 14/17] block: support FALLOC_FL_PUNCH_HOLE trimming Paolo Bonzini
2012-03-09 8:20 ` Chris Wedgwood
2012-03-09 8:31 ` Paolo Bonzini
2012-03-09 8:35 ` Chris Wedgwood
2012-03-09 8:40 ` Paolo Bonzini
2012-03-09 10:31 ` Stefan Hajnoczi
2012-03-09 10:43 ` Paolo Bonzini
2012-03-09 10:53 ` Stefan Hajnoczi
2012-03-09 10:57 ` Paolo Bonzini
2012-03-09 20:36 ` Richard Laager
2012-03-12 9:34 ` Paolo Bonzini
2012-03-24 15:40 ` Christoph Hellwig
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 15/17] raw: add get_info Paolo Bonzini
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 16/17] qemu-io: fix the alloc command Paolo Bonzini
2012-03-08 17:15 ` [Qemu-devel] [RFC PATCH 17/17] raw: implement is_allocated Paolo Bonzini
2012-03-24 15:42 ` Christoph Hellwig
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