[PATCH net-next 8/8] vhost_net: use lockless peeking for skb array during busy polling
From: Jason Wang <jasowang@redhat.com>
Date: 2017-03-21 04:12:54
Also in:
kvm, lkml, netdev
Subsystem:
the rest, virtio host (vhost) · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
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@redhat.com> --- 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);
@@ -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