On Thu, 2010-10-28 at 07:20 +0200, Michael S. Tsirkin wrote:

My concern is this can delay signalling for unlimited time.
Could you pls test this with guests that do not have
2b5bbe3b8bee8b38bdc27dd9c0270829b6eb7eeb
b0c39dbdc204006ef3558a66716ff09797619778
that is 2.6.31 and older?

I will test it out.

This seems to be slighltly out of spec, even though
for TX, signals are less important.
Two ideas:
1. How about writing out used, just delaying the signal?
   This way we don't have to queue separately.
2. How about flushing out queued stuff before we exit
   the handle_tx loop? That would address most of
   the spec issue. 

I will modify the patch to test out the performance for both 1 & 2
approaches.

Thanks
Shirley