pkt_sched: Check the state of tx_queue in dequeue_skb() (ebf05982) · Commits · 戴 / test

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 <jarkao2@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/sched/sch_generic.c

+14 −4

Original line number	Diff line number	Diff line
		@@ -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;
		struct sk_buff *skb = skb_peek(&q->requeue);

		if (unlikely(skb)) {
		struct net_device *dev = qdisc_dev(q);
		struct netdev_queue *txq;

		skb = __skb_dequeue(&q->requeue);
		if (!skb)
		/* 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;
		}

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