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net: vhost: factor out busy polling logic to vhost_net_busy_poll()

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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@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tonghao Zhang 2018-09-25 05:36:51 -07:00 committed by David S. Miller
parent a6a67a2f34
commit dc151282bb
1 changed files with 70 additions and 40 deletions
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110
drivers/vhost/net.c
View File

@ -480,6 +480,74 @@ signal_used:
nvq->batched_xdp = 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 || sock_has_rx_data(sock))
vhost_net_busy_poll_try_queue(net, vq);
else if (!poll_rx) /* 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,
@ -897,16 +965,6 @@ 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)
{
@ -914,41 +972,13 @@ 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);
}