From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: [PATCH net-next 8/8] vhost_net: use lockless peeking for skb array during busy polling Date: Tue, 21 Mar 2017 12:04:47 +0800 Message-ID: <1490069087-4783-9-git-send-email-jasowang@redhat.com> References: <1490069087-4783-1-git-send-email-jasowang@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: In-Reply-To: <1490069087-4783-1-git-send-email-jasowang@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: netdev.vger.kernel.org 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 --- 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