Tonghao Zhang
2018-Sep-09 10:58 UTC
[PATCH net-next v8 3/7] net: vhost: factor out busy polling logic to vhost_net_busy_poll()
On Tue, Aug 21, 2018 at 11:15 AM Jason Wang <jasowang at redhat.com> wrote:> > > > On 2018?08?19? 20:11, xiangxia.m.yue at gmail.com wrote: > > From: Tonghao Zhang <xiangxia.m.yue at gmail.com> > > > > 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. > > > > To avoid duplicate codes, introduce the helper functions: > > * sock_has_rx_data(changed from sk_has_rx_data) > > * vhost_net_busy_poll_try_queue > > > > Signed-off-by: Tonghao Zhang <xiangxia.m.yue at gmail.com> > > --- > > drivers/vhost/net.c | 111 +++++++++++++++++++++++++++++++++------------------- > > 1 file changed, 71 insertions(+), 40 deletions(-) > > > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > > index 32c1b52..453c061 100644 > > --- a/drivers/vhost/net.c > > +++ b/drivers/vhost/net.c > > @@ -440,6 +440,75 @@ static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq) > > nvq->done_idx = 0; > > } > > > > +static int sock_has_rx_data(struct socket *sock) > > +{ > > + if (unlikely(!sock)) > > + return 0; > > + > > + if (sock->ops->peek_len) > > + return sock->ops->peek_len(sock); > > + > > + return skb_queue_empty(&sock->sk->sk_receive_queue); > > +} > > + > > +static void vhost_net_busy_poll_try_queue(struct vhost_net *net, > > + struct vhost_virtqueue *vq) > > +{ > > + if (!vhost_vq_avail_empty(&net->dev, vq)) { > > + vhost_poll_queue(&vq->poll); > > + } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { > > + vhost_disable_notify(&net->dev, vq); > > + vhost_poll_queue(&vq->poll); > > + } > > +} > > + > > +static void vhost_net_busy_poll(struct vhost_net *net, > > + struct vhost_virtqueue *rvq, > > + struct vhost_virtqueue *tvq, > > + bool *busyloop_intr, > > + bool poll_rx) > > +{ > > + unsigned long busyloop_timeout; > > + unsigned long endtime; > > + struct socket *sock; > > + struct vhost_virtqueue *vq = poll_rx ? tvq : rvq; > > + > > + mutex_lock_nested(&vq->mutex, poll_rx ? VHOST_NET_VQ_TX: VHOST_NET_VQ_RX); > > + vhost_disable_notify(&net->dev, vq); > > + sock = rvq->private_data; > > + > > + busyloop_timeout = poll_rx ? rvq->busyloop_timeout: > > + tvq->busyloop_timeout; > > + > > + preempt_disable(); > > + endtime = busy_clock() + busyloop_timeout; > > + > > + while (vhost_can_busy_poll(endtime)) { > > + if (vhost_has_work(&net->dev)) { > > + *busyloop_intr = true; > > + break; > > + } > > + > > + if ((sock_has_rx_data(sock) && > > + !vhost_vq_avail_empty(&net->dev, rvq)) || > > + !vhost_vq_avail_empty(&net->dev, tvq)) > > + break; > > + > > + cpu_relax(); > > + } > > + > > + preempt_enable(); > > + > > + if (poll_rx) > > + vhost_net_busy_poll_try_queue(net, tvq); > > + else if (sock_has_rx_data(sock)) > > + vhost_net_busy_poll_try_queue(net, rvq); > > This could be simplified like: > > if (poll_rx || sock_has_rx_data(sock)) > vhost_net_busy_poll_try_queue(net, vq);done, thanks> Thanks > > > + else /* On tx here, sock has no rx data. */ > > + vhost_enable_notify(&net->dev, rvq); > > + > > + mutex_unlock(&vq->mutex); > > +} > > + > > static int vhost_net_tx_get_vq_desc(struct vhost_net *net, > > struct vhost_net_virtqueue *nvq, > > unsigned int *out_num, unsigned int *in_num, > > @@ -753,16 +822,6 @@ static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk) > > return len; > > } > > > > -static int sk_has_rx_data(struct sock *sk) > > -{ > > - struct socket *sock = sk->sk_socket; > > - > > - if (sock->ops->peek_len) > > - return sock->ops->peek_len(sock); > > - > > - return skb_queue_empty(&sk->sk_receive_queue); > > -} > > - > > static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, > > bool *busyloop_intr) > > { > > @@ -770,41 +829,13 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, > > struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX]; > > struct vhost_virtqueue *rvq = &rnvq->vq; > > struct vhost_virtqueue *tvq = &tnvq->vq; > > - unsigned long uninitialized_var(endtime); > > int len = peek_head_len(rnvq, sk); > > > > - if (!len && tvq->busyloop_timeout) { > > + if (!len && rvq->busyloop_timeout) { > > /* Flush batched heads first */ > > vhost_net_signal_used(rnvq); > > /* Both tx vq and rx socket were polled here */ > > - mutex_lock_nested(&tvq->mutex, VHOST_NET_VQ_TX); > > - vhost_disable_notify(&net->dev, tvq); > > - > > - preempt_disable(); > > - endtime = busy_clock() + tvq->busyloop_timeout; > > - > > - while (vhost_can_busy_poll(endtime)) { > > - if (vhost_has_work(&net->dev)) { > > - *busyloop_intr = true; > > - break; > > - } > > - if ((sk_has_rx_data(sk) && > > - !vhost_vq_avail_empty(&net->dev, rvq)) || > > - !vhost_vq_avail_empty(&net->dev, tvq)) > > - break; > > - cpu_relax(); > > - } > > - > > - preempt_enable(); > > - > > - 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); > > - } > > - > > - mutex_unlock(&tvq->mutex); > > + vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true); > > > > len = peek_head_len(rnvq, sk); > > } >