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Re: [Qemu-devel] [PATCH v5 13/15] block: add support for partial streami
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH v5 13/15] block: add support for partial streaming |
Date: |
Tue, 17 Jan 2012 15:05:29 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111115 Thunderbird/8.0 |
Am 17.01.2012 14:50, schrieb Marcelo Tosatti:
> On Tue, Jan 17, 2012 at 02:27:04PM +0100, Kevin Wolf wrote:
>> Am 13.01.2012 14:14, schrieb Stefan Hajnoczi:
>>> From: Marcelo Tosatti <address@hidden>
>>>
>>> Add support for streaming data from an intermediate section of the
>>> image chain (see patch and documentation for details).
>>>
>>> Signed-off-by: Marcelo Tosatti <address@hidden>
>>> Signed-off-by: Stefan Hajnoczi <address@hidden>
>>
>> I'm afraid that in the review for the previous version I couldn't see
>> the wood for the trees... This does limit the COR requests issued by
>> image streaming, but not those issued by the guest. Am I missing
>> something? This is not what we want, is it?
>
> What you mean "limit the COR requests"?
base -> sn1 -> sn2
You only want to copy the content of sn1 into sn2 and keep base. The
streaming coroutine is doing the right thing because it checks
is_allocated_base. However, if it is the guest that reads some data from
base, COR copies it into sn2 even though it's in the common base file.
Maybe streaming shouldn't enable normal COR on images, but instead of
calling bdrv_co_read it could directly call bdrv_co_copy_on_readv().
Kevin
- [Qemu-devel] [PATCH v5 07/15] qmp: add block_job_set_speed command, (continued)
- [Qemu-devel] [PATCH v5 07/15] qmp: add block_job_set_speed command, Stefan Hajnoczi, 2012/01/13
- [Qemu-devel] [PATCH v5 14/15] docs: describe live block operations, Stefan Hajnoczi, 2012/01/13
- [Qemu-devel] [PATCH v5 11/15] block: add bdrv_find_backing_image, Stefan Hajnoczi, 2012/01/13
- [Qemu-devel] [PATCH v5 10/15] blockdev: make image streaming safe across hotplug, Stefan Hajnoczi, 2012/01/13
- [Qemu-devel] [PATCH v5 12/15] add QERR_BASE_NOT_FOUND, Stefan Hajnoczi, 2012/01/13
- [Qemu-devel] [PATCH v5 08/15] qmp: add block_job_cancel command, Stefan Hajnoczi, 2012/01/13
- [Qemu-devel] [PATCH v5 06/15] qmp: add block_stream command, Stefan Hajnoczi, 2012/01/13
- [Qemu-devel] [PATCH v5 13/15] block: add support for partial streaming, Stefan Hajnoczi, 2012/01/13
[Qemu-devel] [PATCH v5 15/15] test: add image streaming test cases, Stefan Hajnoczi, 2012/01/13
[Qemu-devel] [PATCH v5 09/15] qmp: add query-block-jobs, Stefan Hajnoczi, 2012/01/13
Re: [Qemu-devel] [PATCH v5 00/15] block: generic image streaming, Luiz Capitulino, 2012/01/16