On Mon, Jul 05, 2010 at 02:16:56PM +0200, Jan Kiszka wrote:
> Avi Kivity wrote:
> > On 07/05/2010 02:13 PM, Jan Kiszka wrote:
> >> That decoupling between state change and acknowledgment worries me.
> >> Dispatching a source to multiple sinks or sharing a sink between
> >> multiple source is no longer cleanly manageable this way. Just look at
> >> the route of some ISA IRQ on x86: You may get an 'ack' from IOAPIC side
> >> and a 'masked' from the ISA side (or vice versa). And the 'masked' will
> >> arrive earlier.
> >
> > I think it is sufficient to only note masks and take action on acks.
>
> We would increment our backlog on injection, decrement it on mask
> notification - and decrement it again on ack.
>
On mask notification backlog is zeroed and not incremented until unmask
notification.
--
Gleb.
