On Mon, Mar 12, 2012 at 5:12 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > Il 12/03/2012 09:59, Zhi Yong Wu ha scritto: >>> However, then I noticed that qemu_can_send_packet is not called very >>> much, and I do not understand why qemu_net_queue_send and >>> qemu_net_queue_send_iov do not call qemu_can_send_packet before calling >>> deliver/deliver_iov. >> >>> If they did, hubs could then do their own flow control via can_receive. >>> When qemu_send_packet returns zero you increment a count of in-flight >>> packets, and a sent-packet callback would decrement the same count. >> >> sent-packet callback is sent_cb here? i noticed that sent_cb is currently NULL. > > Yes. > >>> When the count is non-zero, can_receive returns false (and vice versa). >>> Can you elaborate this? since can_receive is called finally by qemu_send_packet, >>> how can can_receive return false or true based on the count? > > Based on counts from the previous sends. thanks. I agree with your opition, but hope to get stefan's comments. > > Paolo -- Regards, Zhi Yong Wu -- 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
