Re: [Qemu-devel] Re: [RFC][PATCH] performance improvement for windows guests, running on top of virtio block device

[Christoph Hellwig]

On Mon, Jan 11, 2010 at 03:13:53PM +0200, Avi Kivity wrote:
> As Dor points out, the call to virtio_blk_handle_output() wants to be 
> before the test for pending, so we scan the ring as early as possible

It could cause a race window where we add an entry to the ring after
we run virtio_blk_handle_output, but before re-enabling the
notification.  But I think my variant of the patch that I just posted
should deal with this in an even better way.