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pkt_sched: Check the state of tx_queue in dequeue_skb()

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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>
This commit is contained in:
Jarek Poplawski 2008-09-22 22:16:23 -07:00 committed by David S. Miller
parent f0876520b0
commit ebf059821e
1 changed files with 13 additions and 3 deletions
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16
net/sched/sch_generic.c
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@ -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);
skb = __skb_dequeue(&q->requeue);
if (!skb)
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;
}