On Fri, Jun 09, 2017 at 06:41:41PM +0800, Wei Wang wrote:
> - if (!virtqueue_indirect_desc_table_add(vq, desc, num)) {
> + if (!virtqueue_indirect_desc_table_add(vq, desc, *num)) {
> virtqueue_kick(vq);
> - wait_event(vb->acked, virtqueue_get_buf(vq, &len));
> - vb->balloon_page_chunk.chunk_num = 0;
> + if (busy_wait)
> + while (!virtqueue_get_buf(vq, &len) &&
> + !virtqueue_is_broken(vq))
> + cpu_relax();
> + else
> + wait_event(vb->acked, virtqueue_get_buf(vq, &len));
This is something I didn't previously notice.
As you always keep a single buffer in flight, you do not
really need indirect at all. Just add all descriptors
in the ring directly, then kick.
E.g.
virtqueue_add_first
virtqueue_add_next
virtqueue_add_last
?
You also want a flag to avoid allocations but there's no need to do it
per descriptor, set it on vq.
--
MST
