From ebf059821ed8a36acd706484b719d14d212ada32 Mon Sep 17 00:00:00 2001 From: Jarek Poplawski Date: Mon, 22 Sep 2008 22:16:23 -0700 Subject: [PATCH] pkt_sched: Check the state of tx_queue in dequeue_skb() Check in dequeue_skb() the state of tx_queue for requeued skb to save on locking and re-requeuing, and possibly remove the current check in qdisc_run(). Based on the idea of Alexander Duyck. Signed-off-by: Jarek Poplawski Signed-off-by: David S. Miller --- net/sched/sch_generic.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 1b508bd1c06c..5e7e0bd38fe8 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -52,11 +52,21 @@ static inline int dev_requeue_skb(struct sk_buff *skb, struct Qdisc *q) static inline struct sk_buff *dequeue_skb(struct Qdisc *q) { - struct sk_buff *skb; - - skb = __skb_dequeue(&q->requeue); - if (!skb) + struct sk_buff *skb = skb_peek(&q->requeue); + + if (unlikely(skb)) { + struct net_device *dev = qdisc_dev(q); + struct netdev_queue *txq; + + /* check the reason of requeuing without tx lock first */ + txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb)); + if (!netif_tx_queue_stopped(txq) && !netif_tx_queue_frozen(txq)) + __skb_unlink(skb, &q->requeue); + else + skb = NULL; + } else { skb = q->dequeue(q); + } return skb; } -- 2.20.1