[Lguest] [PATCH 14/18] virtio: add api for delayed callbacks

[Rusty Russell]

On Sun, 15 May 2011 15:48:18 +0300, "Michael S. Tsirkin" <mst at redhat.com> wrote:
> On Mon, May 09, 2011 at 03:27:33PM +0930, Rusty Russell wrote:
> > On Wed, 4 May 2011 23:52:33 +0300, "Michael S. Tsirkin" <mst at redhat.com> wrote:
> > > Add an API that tells the other side that callbacks
> > > should be delayed until a lot of work has been done.
> > > Implement using the new used_event feature.
> > 
> > Since you're going to add a capacity query anyway, why not add the
> > threshold argument here?
> 
> I thought that if we keep the API kind of generic
> there might be more of a chance that future transports
> will be able to implement it. For example, with an
> old host we can't commit to a specific index.

No, it's always a hint anyway: you can be notified before the threshold
is reached.  But best make it explicit I think.

Cheers,
Rusty.