On 2018年08月19日 20:11, 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.
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@xxxxxxxxx>
---
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);
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);
}
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