[Lguest] [PATCHv2 10/14] virtio_net: limit xmit polling

[Rusty Russell]

On Mon, 23 May 2011 14:19:00 +0300, "Michael S. Tsirkin" <mst at redhat.com> wrote:
> I do understand how it seems a waste to leave direct space
> in the ring while we might in practice have space
> due to indirect. Didn't come up with a nice way to
> solve this yet - but 'no worse than now :)'

Let's just make it "bool free_old_xmit_skbs(unsigned int max)".  max ==
2 for the normal xmit path, so we're low latency but we keep ahead on
average.  max == -1 for the "we're out of capacity, we may have to stop
the queue".

That keeps it simple and probably the right thing...

Thanks,
Rusty.