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authorEric Dumazet <eric.dumazet@gmail.com>2011-01-21 16:26:09 -0800
committerDavid S. Miller <davem@davemloft.net>2011-01-21 16:26:09 -0800
commit23624935e0c4b04730ed8d7d21f0cd25b2c2cda1 (patch)
tree3fedc885d6bcd72c94fc239ae2ef98937f77c722 /net/sched/sch_fifo.c
parentbb134d2298b49f50cf6d9388410fba96272905dc (diff)
downloadlinux-23624935e0c4b04730ed8d7d21f0cd25b2c2cda1.tar.bz2
net_sched: TCQ_F_CAN_BYPASS generalization
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>
Diffstat (limited to 'net/sched/sch_fifo.c')
-rw-r--r--net/sched/sch_fifo.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/net/sched/sch_fifo.c b/net/sched/sch_fifo.c
index b3075f8a196b..f7290d2542c2 100644
--- a/net/sched/sch_fifo.c
+++ b/net/sched/sch_fifo.c
@@ -64,11 +64,13 @@ static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch)
static int fifo_init(struct Qdisc *sch, struct nlattr *opt)
{
struct fifo_sched_data *q = qdisc_priv(sch);
+ bool bypass;
+ bool is_bfifo = sch->ops == &bfifo_qdisc_ops;
if (opt == NULL) {
u32 limit = qdisc_dev(sch)->tx_queue_len ? : 1;
- if (sch->ops == &bfifo_qdisc_ops)
+ if (is_bfifo)
limit *= psched_mtu(qdisc_dev(sch));
q->limit = limit;
@@ -81,6 +83,15 @@ static int fifo_init(struct Qdisc *sch, struct nlattr *opt)
q->limit = ctl->limit;
}
+ if (is_bfifo)
+ bypass = q->limit >= psched_mtu(qdisc_dev(sch));
+ else
+ bypass = q->limit >= 1;
+
+ if (bypass)
+ sch->flags |= TCQ_F_CAN_BYPASS;
+ else
+ sch->flags &= ~TCQ_F_CAN_BYPASS;
return 0;
}