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Subject: Re: [Qemu-devel] [PATCH 00/13] linux-aio/virtio-scsi: support
 AioContext wide IO submission as batch
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To: Ming Lei <ming.lei@canonical.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, Fam Zheng <famz@redhat.com>, qemu-devel <qemu-devel@nongnu.org>, Stefan Hajnoczi <stefanha@redhat.com>



On 22/11/2014 13:33, Ming Lei wrote:
> > these patches are interesting.  I would like to compare them with the
> > opposite approach (and, I think, more similar to your old work) where
> > the qemu_laio_state API is moved entirely into AioContext, with lazy
> > allocation (reference-counted too, probably).
> 
> Yes, it can be done in that way, but the feature is linux native aio
> specific, so it might not be good to put it into AioContext.

I think it's not a problem as long as the eventfd and io queue is
created lazily.  My main issue with these series is that
aio_attach_aio_bs() (and detach) feels like a very ad hoc API.  Adding
io queue support directly in AioContext sounds better.

> Basically most of the implementation should be same, and the
> difference should be where the io queue is put.

Yes, the change is not big.

Paolo