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Re: [Qemu-devel] [PATCH 4/4] block: add bdrv_co_discard and bdrv_aio_dis
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH 4/4] block: add bdrv_co_discard and bdrv_aio_discard support |
Date: |
Fri, 14 Oct 2011 16:32:57 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:7.0) Gecko/20110927 Thunderbird/7.0 |
Am 14.10.2011 16:24, schrieb Paolo Bonzini:
> On 10/14/2011 04:23 PM, Kevin Wolf wrote:
>>> This similarly adds support for coroutine and asynchronous discard.
>>>
>>> Signed-off-by: Paolo Bonzini<address@hidden>
>>
>> Do we really need bdrv_discard and bdrv_aio_discard in the backends? I
>> think it makes sense to have a bdrv_aio_discard() in block.h as AIO
>> generally fits well for device models, but I would just require
>> bdrv_co_discard for any block drivers implementing discard.
>
> bdrv_discard is needed for now since I wouldn't like to conflate this
> patch with the qcow2 patch.
Okay, that makes sense. Then I'll drop it when I convert qcow2.
> I can certainly drop aio_discard from the backends, but I'm not sure how
> heavy can fallocate be (with FALLOC_FL_PUNCH_HOLE). Probably not much,
> but I think there's no guarantee of O(1) behavior especially with
> filesystems like ecryptfs. So you would need to go through the thread
> pool and aio_discard would come in handy.
Sure, but the coroutine interface should be just as good for
implementing it this way in raw-posix.
Kevin
- Re: [Qemu-devel] [PATCH 2/4] block: unify flush implementations, (continued)
- Re: [Qemu-devel] [PATCH 2/4] block: unify flush implementations, Paolo Bonzini, 2011/10/14
- Re: [Qemu-devel] [PATCH 2/4] block: unify flush implementations, Kevin Wolf, 2011/10/14
- Re: [Qemu-devel] [PATCH 2/4] block: unify flush implementations, Paolo Bonzini, 2011/10/14
- Re: [Qemu-devel] [PATCH 2/4] block: unify flush implementations, Kevin Wolf, 2011/10/14
- Re: [Qemu-devel] [PATCH 2/4] block: unify flush implementations, Paolo Bonzini, 2011/10/14
- Re: [Qemu-devel] [PATCH 2/4] block: unify flush implementations, Stefan Hajnoczi, 2011/10/14
- Re: [Qemu-devel] [PATCH 2/4] block: unify flush implementations, Paolo Bonzini, 2011/10/14
[Qemu-devel] [PATCH 4/4] block: add bdrv_co_discard and bdrv_aio_discard support, Paolo Bonzini, 2011/10/14