On 2018/07/04 13:31, xiangxia.m.yue@xxxxxxxxx wrote:
...
> +static void vhost_net_busy_poll(struct vhost_net *net,
> + struct vhost_virtqueue *rvq,
> + struct vhost_virtqueue *tvq,
> + bool rx)
> +{
> + unsigned long uninitialized_var(endtime);
> + unsigned long busyloop_timeout;
> + struct socket *sock;
> + struct vhost_virtqueue *vq = rx ? tvq : rvq;
> +
> + mutex_lock_nested(&vq->mutex, rx ? VHOST_NET_VQ_TX: VHOST_NET_VQ_RX);
> +
> + vhost_disable_notify(&net->dev, vq);
> + sock = rvq->private_data;
> + busyloop_timeout = rx ? rvq->busyloop_timeout : tvq->busyloop_timeout;
> +
> + preempt_disable();
> + endtime = busy_clock() + busyloop_timeout;
> + while (vhost_can_busy_poll(tvq->dev, endtime) &&
> + !(sock && sk_has_rx_data(sock->sk)) &&
> + vhost_vq_avail_empty(tvq->dev, tvq))
> + cpu_relax();
> + preempt_enable();
> +
> + if ((rx && !vhost_vq_avail_empty(&net->dev, vq)) ||
> + (!rx && (sock && sk_has_rx_data(sock->sk)))) {
> + vhost_poll_queue(&vq->poll);
> + } else if (vhost_enable_notify(&net->dev, vq) && rx) {
Hmm... on tx here sock has no rx data, so you are waiting for sock
wakeup for rx and vhost_enable_notify() seems not needed. Do you want
this actually?
} else if (rx && vhost_enable_notify(&net->dev, vq)) {
> + vhost_disable_notify(&net->dev, vq);
> + vhost_poll_queue(&vq->poll);
> + }
--
Toshiaki Makita
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