Re: [Qemu-block] [Qemu-devel] [PATCH v3 for-4.2 0/3] block: BDRV_REQ_PREFETCH

[Eric Blake]

On 7/29/19 10:00 AM, Stefan Hajnoczi wrote:
> On Thu, Jul 25, 2019 at 01:05:47PM +0300, Vladimir Sementsov-Ogievskiy wrote:
>> Hi all!
>>
>> Here is small new read flag: BDRV_REQ_PREFETCH, which in combination with
>> BDRV_REQ_COPY_ON_READ does copy-on-read without
>> extra buffer for read data. This means that only parts that needs COR
>> will be actually read and only corresponding buffers allocated, no more.
>>
>> This allows to improve a bit block-stream and NBD_CMD_CACHE
>>
>> v3: rebase 02 on master, fix commit message of 03.
>>
>> v2: change interface to be just one flag BDRV_REQ_PREFETCH
>>
>> v1 was "[PATCH 0/3] block: blk_co_pcache"
>>    https://lists.gnu.org/archive/html/qemu-devel/2019-06/msg01047.html
>>
>> Vladimir Sementsov-Ogievskiy (3):
>>   block: implement BDRV_REQ_PREFETCH
>>   block/stream: use BDRV_REQ_PREFETCH
>>   nbd: improve CMD_CACHE: use BDRV_REQ_PREFETCH
>>
>>  include/block/block.h |  8 +++++++-
>>  block/io.c            | 18 ++++++++++++------
>>  block/stream.c        | 20 +++++++-------------
>>  nbd/server.c          | 43 +++++++++++++++++++++++++++++++++++--------
>>  4 files changed, 61 insertions(+), 28 deletions(-)
>>
>> -- 
>> 2.18.0
>>
>>
> 
> Reviewed-by: Stefan Hajnoczi <address@hidden>
> 

I'm happy to queue this one through my NBD tree for 4.2.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

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