On Mon, Jul 23, 2018 at 5:58 PM Toshiaki Makita
<makita.toshiaki@xxxxxxxxxxxxx> wrote:
>
> On 2018/07/22 3:04, xiangxia.m.yue@xxxxxxxxx wrote:
> > From: Tonghao Zhang <xiangxia.m.yue@xxxxxxxxx>
> >
> > Factor out generic busy polling logic and will be
> > used for in tx path in the next patch. And with the patch,
> > qemu can set differently the busyloop_timeout for rx queue.
> >
> > Signed-off-by: Tonghao Zhang <xiangxia.m.yue@xxxxxxxxx>
> > ---
> ...
> > +static void vhost_net_busy_poll_vq_check(struct vhost_net *net,
> > + struct vhost_virtqueue *rvq,
> > + struct vhost_virtqueue *tvq,
> > + bool rx)
> > +{
> > + struct socket *sock = rvq->private_data;
> > +
> > + if (rx) {
> > + if (!vhost_vq_avail_empty(&net->dev, tvq)) {
> > + vhost_poll_queue(&tvq->poll);
> > + } else if (unlikely(vhost_enable_notify(&net->dev, tvq))) {
> > + vhost_disable_notify(&net->dev, tvq);
> > + vhost_poll_queue(&tvq->poll);
> > + }
> > + } else if ((sock && sk_has_rx_data(sock->sk)) &&
> > + !vhost_vq_avail_empty(&net->dev, rvq)) {
> > + vhost_poll_queue(&rvq->poll);
>
> Now we wait for vq_avail for rx as well, I think you cannot skip
> vhost_enable_notify() on tx. Probably you might want to do:
I think vhost_enable_notify is needed.
> } else if (sock && sk_has_rx_data(sock->sk)) {
> if (!vhost_vq_avail_empty(&net->dev, rvq)) {
> vhost_poll_queue(&rvq->poll);
> } else if (unlikely(vhost_enable_notify(&net->dev, rvq))) {
> vhost_disable_notify(&net->dev, rvq);
> vhost_poll_queue(&rvq->poll);
> }
> }
As Jason review as before, we only want rx kick when packet is pending at
socket but we're out of available buffers. So we just enable notify,
but not poll it ?
} else if ((sock && sk_has_rx_data(sock->sk)) &&
!vhost_vq_avail_empty(&net->dev, rvq)) {
vhost_poll_queue(&rvq->poll);
else {
vhost_enable_notify(&net->dev, rvq);
}
> Also it's better to care vhost_net_disable_vq()/vhost_net_enable_vq() on tx?
I cant find why it is better, if necessary, we can do it.
> --
> Toshiaki Makita
>
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