From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: [net-next rfc V2 1/8] macvtap: do not add self to waitqueue if doing a nonblock read Date: Fri, 31 May 2013 17:53:18 +0800 Message-ID: <1369994005-5943-2-git-send-email-jasowang@redhat.com> References: <1369994005-5943-1-git-send-email-jasowang@redhat.com> Cc: Jason Wang To: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, mst@redhat.com Return-path: In-Reply-To: <1369994005-5943-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org There's no need to add self to waitqueue if doing a nonblock read. This could help to avoid the spinlock contention. Signed-off-by: Jason Wang --- drivers/net/macvtap.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 59e9605..2395062 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -845,7 +845,9 @@ static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb, ssize_t ret = 0; while (len) { - prepare_to_wait(sk_sleep(&q->sk), &wait, TASK_INTERRUPTIBLE); + if (!noblock) + prepare_to_wait(sk_sleep(&q->sk), &wait, + TASK_INTERRUPTIBLE); /* Read frames from the queue */ skb = skb_dequeue(&q->sk.sk_receive_queue); @@ -867,7 +869,8 @@ static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb, break; } - finish_wait(sk_sleep(&q->sk), &wait); + if (!noblock) + finish_wait(sk_sleep(&q->sk), &wait); return ret; } -- 1.7.1