On Tue, Feb 01, 2011 at 01:28:45PM -0800, Shirley Ma wrote: > On Tue, 2011-02-01 at 23:21 +0200, Michael S. Tsirkin wrote: > > Confused. We compare capacity to skb frags, no? > > That's sg I think ... > > Current guest kernel use indirect buffers, num_free returns how many > available descriptors not skb frags. So it's wrong here. > > Shirley I see. Good point. In other words when we complete the buffer it was indirect, but when we add a new one we can not allocate indirect so we consume. And then we start the queue and add will fail. I guess we need some kind of API to figure out whether the buf we complete was indirect? Another failure mode is when skb_xmit_done wakes the queue: it might be too early, there might not be space for the next packet in the vq yet. A solution might be to keep some kind of pool around for indirect, we wanted to do it for block anyway ... -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
