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net_sched: TCQ_F_CAN_BYPASS generalization

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Now qdisc stab is handled before TCQ_F_CAN_BYPASS test in
__dev_xmit_skb(), we can generalize TCQ_F_CAN_BYPASS to other qdiscs
than pfifo_fast : pfifo, bfifo, pfifo_head_drop and sfq

SFQ is special because it can have external classifiers, and in these
cases, we cannot bypass queue discipline (packet could be dropped by
classifier) without admin asking it, or further changes.

Its worth doing this, especially for SFQ, avoiding dirtying memory in
case no packets are already waiting in queue.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2011-01-21 16:26:09 -08:00
committed by David S. Miller
parent bb134d2298
commit 23624935e0
5 changed files with 20 additions and 6 deletions
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5
net/sched/sch_generic.c
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@@ -527,6 +527,8 @@ static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt)
for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
skb_queue_head_init(band2list(priv, prio));
/* Can by-pass the queue discipline */
qdisc->flags |= TCQ_F_CAN_BYPASS;
return 0;
}
@@ -691,9 +693,6 @@ static void attach_one_default_qdisc(struct net_device *dev,
netdev_info(dev, "activation failed\n");
return;
}
/* Can by-pass the queue discipline for default qdisc */
qdisc->flags |= TCQ_F_CAN_BYPASS;
}
dev_queue->qdisc_sleeping = qdisc;
}