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From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 3/4] block: add bdrv_aio_flush operation
References: <20090831201627.GA4811@lst.de> <20090831201730.GC4874@lst.de>
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To: Christoph Hellwig <hch@lst.de>
Cc: qemu-devel@nongnu.org

On 08/31/2009 11:17 PM, Christoph Hellwig wrote:
> Instead stalling the VCPU while serving a cache flush try to do it
> asynchronously.  Use our good old helper thread pool to issue an
> asynchronous fdatasync for raw-posix.  Note that while Linux AIO
> implements a fdatasync operation it is not useful for us because
> it isn't actually implement in asynchronous fashion.
>
>    

Doesn't aio_flush() need to wait for all previously issued requests to 
complete?

We can require callers to do that, but it seems quite a burden.

> For now only use it in IDE because virtio-blk doesn't implement
> cache flusing yet (will be fixed in patch 4/4) and the interface between
> the HBA emulation and scsi-disk will need some changes to accomodate
> it for scsi (will be a separate patch series).
>    

IDE integration should be in a separate patch.


Patch has some tabs.

-- 
error compiling committee.c: too many arguments to function