From 23624935e0c4b04730ed8d7d21f0cd25b2c2cda1 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 21 Jan 2011 16:26:09 -0800 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/sched/sch_fifo.c | 13 ++++++++++++- net/sched/sch_generic.c | 5 ++--- net/sched/sch_mq.c | 1 - net/sched/sch_mqprio.c | 1 - net/sched/sch_sfq.c | 6 ++++++ 5 files changed, 20 insertions(+), 6 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; } diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index cc17e794c41e..0da09d508737 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -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; } diff --git a/net/sched/sch_mq.c b/net/sched/sch_mq.c index ecc302f4d2a1..ec5cbc848963 100644 --- a/net/sched/sch_mq.c +++ b/net/sched/sch_mq.c @@ -61,7 +61,6 @@ static int mq_init(struct Qdisc *sch, struct nlattr *opt) TC_H_MIN(ntx + 1))); if (qdisc == NULL) goto err; - qdisc->flags |= TCQ_F_CAN_BYPASS; priv->qdiscs[ntx] = qdisc; } diff --git a/net/sched/sch_mqprio.c b/net/sched/sch_mqprio.c index 8620c65f480a..fbc6f53cb1b7 100644 --- a/net/sched/sch_mqprio.c +++ b/net/sched/sch_mqprio.c @@ -130,7 +130,6 @@ static int mqprio_init(struct Qdisc *sch, struct nlattr *opt) err = -ENOMEM; goto err; } - qdisc->flags |= TCQ_F_CAN_BYPASS; priv->qdiscs[i] = qdisc; } diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c index 156ad30980b5..fdba52aa053d 100644 --- a/net/sched/sch_sfq.c +++ b/net/sched/sch_sfq.c @@ -560,6 +560,10 @@ static int sfq_init(struct Qdisc *sch, struct nlattr *opt) slot_queue_init(&q->slots[i]); sfq_link(q, i); } + if (q->limit >= 1) + sch->flags |= TCQ_F_CAN_BYPASS; + else + sch->flags &= ~TCQ_F_CAN_BYPASS; return 0; } @@ -611,6 +615,8 @@ static unsigned long sfq_get(struct Qdisc *sch, u32 classid) static unsigned long sfq_bind(struct Qdisc *sch, unsigned long parent, u32 classid) { + /* we cannot bypass queue discipline anymore */ + sch->flags &= ~TCQ_F_CAN_BYPASS; return 0; } -- 2.30.2