From: Eric Blake <eblake@redhat.com>
To: Peter Lieven <pl@kamp.de>
Cc: kwolf@redhat.com, ronniesahlberg@gmail.com, stefanha@redhat.com,
qemu-devel@nongnu.org, anthony@codemonkey.ws,
pbonzini@redhat.com
Subject: Re: [Qemu-devel] [PATCH 03/12] block: introduce BDRV_REQ_MAY_UNMAP in bdrv_co_write_zeroes
Date: Fri, 13 Sep 2013 12:07:12 -0600 [thread overview]
Message-ID: <52335450.9070802@redhat.com> (raw)
In-Reply-To: <1379067909-22984-4-git-send-email-pl@kamp.de>
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On 09/13/2013 04:25 AM, Peter Lieven wrote:
> the BDRV_REQ_MAY_UNMAP flag is used to indicate that block driver
> is allowed to optimze a write zeroes request by unmapping (discarding)
s/optimze/optimize/
> blocks if it is guaranteed that the result will read back as
> zeroes.
>
> the flag is only passed to the driver if the block device is
> opened with BDRV_O_UNMAP.
>
> Signed-off-by: Peter Lieven <pl@kamp.de>
> ---
> +++ b/include/block/block.h
> @@ -65,6 +65,7 @@ typedef struct BlockDevOps {
> typedef enum {
> BDRV_REQ_COPY_ON_READ = 0x1,
> BDRV_REQ_ZERO_WRITE = 0x2,
> + BDRV_REQ_MAY_UNMAP = 0x4,
Now that this enum is public, it would be useful to have inline
documentation, rather than making people dig up the git history of when
it was introduced to learn its semantics.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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next prev parent reply other threads:[~2013-09-13 18:07 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-13 10:24 [Qemu-devel] [PATCH 00/12] block: logical block provisioning enhancements Peter Lieven
2013-09-13 10:24 ` [Qemu-devel] [PATCH 01/12] block: make BdrvRequestFlags public Peter Lieven
2013-09-13 16:29 ` Eric Blake
2013-09-13 10:24 ` [Qemu-devel] [PATCH 02/12] block: add flags to bdrv_*_write_zeroes Peter Lieven
2013-09-13 16:58 ` Eric Blake
2013-09-13 10:25 ` [Qemu-devel] [PATCH 03/12] block: introduce BDRV_REQ_MAY_UNMAP in bdrv_co_write_zeroes Peter Lieven
2013-09-13 18:07 ` Eric Blake [this message]
2013-09-13 10:25 ` [Qemu-devel] [PATCH 04/12] iscsi: add .bdrv_co_write_zeroes Peter Lieven
2013-09-13 18:10 ` Eric Blake
2013-09-13 10:25 ` [Qemu-devel] [PATCH 05/12] block: add logical block provisioning information to BlockDriverInfo Peter Lieven
2013-09-13 10:34 ` Paolo Bonzini
2013-09-13 10:44 ` Peter Lieven
2013-09-13 11:45 ` Paolo Bonzini
2013-09-13 12:22 ` Peter Lieven
2013-09-13 12:58 ` Paolo Bonzini
2013-09-16 11:30 ` Peter Lieven
2013-09-16 11:37 ` Paolo Bonzini
2013-09-13 10:25 ` [Qemu-devel] [PATCH 06/12] iscsi: add .bdrv_get_info Peter Lieven
2013-09-13 18:19 ` Eric Blake
2013-09-13 10:25 ` [Qemu-devel] [PATCH 07/12] block: introduce bdrv_zeroize Peter Lieven
2013-09-13 10:47 ` Peter Lieven
2013-09-13 18:23 ` Eric Blake
2013-09-13 10:25 ` [Qemu-devel] [PATCH 08/12] qemu-img: conditionally zero out target on convert Peter Lieven
2013-09-13 10:36 ` Paolo Bonzini
2013-09-13 10:46 ` Peter Lieven
2013-09-13 11:35 ` Paolo Bonzini
2013-09-13 18:25 ` Eric Blake
2013-09-13 19:48 ` Peter Lieven
2013-09-13 19:52 ` Eric Blake
2013-09-16 11:01 ` Paolo Bonzini
2013-09-13 10:25 ` [Qemu-devel] [PATCH 09/12] block/get_block_status: set *pnum = 0 on error Peter Lieven
2013-09-13 18:26 ` Eric Blake
2013-09-13 10:25 ` [Qemu-devel] [PATCH 10/12] block/get_block_status: avoid segfault if there is no backing_hd Peter Lieven
2013-09-13 18:26 ` Eric Blake
2013-09-13 10:25 ` [Qemu-devel] [PATCH 11/12] block/get_block_status: avoid redundant callouts on raw devices Peter Lieven
2013-09-13 18:28 ` Eric Blake
2013-09-13 10:25 ` [Qemu-devel] [PATCH 12/12] block/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocks Peter Lieven
2013-09-13 13:53 ` Eric Blake
2013-09-16 5:47 ` Peter Lieven
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