On 2018年07月04日 17:46, Tonghao Zhang wrote:
On Wed, Jul 4, 2018 at 5:18 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
On 2018年07月04日 15:59, Toshiaki Makita wrote:
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)) {
Right, rx need to be checked first here.
thanks， if we dont call the vhost_enable_notify for tx. so we dont
need to call vhost_disable_notify for tx?
@@ -451,7 +451,9 @@ static void vhost_net_busy_poll(struct vhost_net *net,
tvq->busyloop_timeout;
mutex_lock_nested(&vq->mutex, rx ? VHOST_NET_VQ_TX: VHOST_NET_VQ_RX);
- vhost_disable_notify(&net->dev, vq);
+
+ if (rx)
+ vhost_disable_notify(&net->dev, vq);
preempt_disable();
endtime = busy_clock() + busyloop_timeout;
Sorry for being unclear. We need enable tx notification at end end of
the loop.
I meant we need replace
+ } else if (vhost_enable_notify(&net->dev, vq) && rx) {
with
+ } else if (rx && vhost_enable_notify(&net->dev, vq)) {
We only need rx notification when there's no avail buffers. This means
we need only enable notification for tx.
And maybe we can simplify the logic as
if (rx) {
......
} else {
......
}
here. (not a must).
Thanks
Thanks
+ vhost_disable_notify(&net->dev, vq);
+ vhost_poll_queue(&vq->poll);
+ }
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