On Tue, Mar 21, 2017 at 12:04:47PM +0800, Jason Wang wrote:
> For the socket that exports its skb array, we can use lockless polling
> to avoid touching spinlock during busy polling.
>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/vhost/net.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 53f09f2..41153a3 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -551,10 +551,13 @@ static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk)
> return len;
> }
>
> -static int sk_has_rx_data(struct sock *sk)
> +static int sk_has_rx_data(struct vhost_net_virtqueue *rvq, struct sock *sk)
> {
> struct socket *sock = sk->sk_socket;
>
> + if (rvq->rx_array)
> + return !__skb_array_empty(rvq->rx_array);
> +
> if (sock->ops->peek_len)
> return sock->ops->peek_len(sock);
>
I don't see which patch adds __skb_array_empty.
> @@ -579,7 +582,7 @@ static int vhost_net_rx_peek_head_len(struct vhost_net *net,
> endtime = busy_clock() + vq->busyloop_timeout;
>
> while (vhost_can_busy_poll(&net->dev, endtime) &&
> - !sk_has_rx_data(sk) &&
> + !sk_has_rx_data(rvq, sk) &&
> vhost_vq_avail_empty(&net->dev, vq))
> cpu_relax();
>
> --
> 2.7.4
