Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756424AbdCUEMy (ORCPT ); Tue, 21 Mar 2017 00:12:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42064 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755482AbdCUEMv (ORCPT ); Tue, 21 Mar 2017 00:12:51 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 3719D81F01 Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jasowang@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 3719D81F01 From: Jason Wang To: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: 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> In-Reply-To: <1490069087-4783-1-git-send-email-jasowang@redhat.com> References: <1490069087-4783-1-git-send-email-jasowang@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 21 Mar 2017 04:05:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1140 Lines: 38 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