diff options
| author | Florian Westphal <fw@strlen.de> | 2016-09-18 00:57:34 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-09-19 01:47:18 -0400 |
| commit | 48da34b7a74201f15315cb1fc40bb9a7bd2b4940 (patch) | |
| tree | 123595224534ee49f1175b6ef8371728b6d31538 /net/sched/sch_netem.c | |
| parent | ed760cb8aae7c2b84c193d4a7637b0c9e752f07e (diff) | |
sched: add and use qdisc_skb_head helpers
This change replaces sk_buff_head struct in Qdiscs with new qdisc_skb_head.
Its similar to the skb_buff_head api, but does not use skb->prev pointers.
Qdiscs will commonly enqueue at the tail of a list and dequeue at head.
While skb_buff_head works fine for this, enqueue/dequeue needs to also
adjust the prev pointer of next element.
The ->prev pointer is not required for qdiscs so we can just leave
it undefined and avoid one cacheline write access for en/dequeue.
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_netem.c')
| -rw-r--r-- | net/sched/sch_netem.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index 0a964b35f8c7..9f7b380cf0a3 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -413,6 +413,16 @@ static struct sk_buff *netem_segment(struct sk_buff *skb, struct Qdisc *sch, return segs; } +static void netem_enqueue_skb_head(struct qdisc_skb_head *qh, struct sk_buff *skb) +{ + skb->next = qh->head; + + if (!qh->head) + qh->tail = skb; + qh->head = skb; + qh->qlen++; +} + /* * Insert one skb into qdisc. * Note: parent depends on return value to account for queue length. @@ -523,7 +533,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff *last; if (sch->q.qlen) - last = skb_peek_tail(&sch->q); + last = sch->q.tail; else last = netem_rb_to_skb(rb_last(&q->t_root)); if (last) { @@ -552,7 +562,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, cb->time_to_send = psched_get_time(); q->counter = 0; - __skb_queue_head(&sch->q, skb); + netem_enqueue_skb_head(&sch->q, skb); sch->qstats.requeues++; } |