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_generic.c | |
| parent | ed760cb8aae7c2b84c193d4a7637b0c9e752f07e (diff) | |
| download | lwn-48da34b7a74201f15315cb1fc40bb9a7bd2b4940.tar.gz lwn-48da34b7a74201f15315cb1fc40bb9a7bd2b4940.zip | |
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_generic.c')
| -rw-r--r-- | net/sched/sch_generic.c | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 73877d9c2bcb..6cfb6e9038c2 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -466,7 +466,7 @@ static const u8 prio2band[TC_PRIO_MAX + 1] = { */ struct pfifo_fast_priv { u32 bitmap; - struct sk_buff_head q[PFIFO_FAST_BANDS]; + struct qdisc_skb_head q[PFIFO_FAST_BANDS]; }; /* @@ -477,7 +477,7 @@ struct pfifo_fast_priv { */ static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0}; -static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv, +static inline struct qdisc_skb_head *band2list(struct pfifo_fast_priv *priv, int band) { return priv->q + band; @@ -489,7 +489,7 @@ static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc, if (qdisc->q.qlen < qdisc_dev(qdisc)->tx_queue_len) { int band = prio2band[skb->priority & TC_PRIO_MAX]; struct pfifo_fast_priv *priv = qdisc_priv(qdisc); - struct sk_buff_head *list = band2list(priv, band); + struct qdisc_skb_head *list = band2list(priv, band); priv->bitmap |= (1 << band); qdisc->q.qlen++; @@ -505,8 +505,8 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc) int band = bitmap2band[priv->bitmap]; if (likely(band >= 0)) { - struct sk_buff_head *list = band2list(priv, band); - struct sk_buff *skb = __qdisc_dequeue_head(list); + struct qdisc_skb_head *qh = band2list(priv, band); + struct sk_buff *skb = __qdisc_dequeue_head(qh); if (likely(skb != NULL)) { qdisc_qstats_backlog_dec(qdisc, skb); @@ -514,7 +514,7 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc) } qdisc->q.qlen--; - if (skb_queue_empty(list)) + if (qh->qlen == 0) priv->bitmap &= ~(1 << band); return skb; @@ -529,9 +529,9 @@ static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc) int band = bitmap2band[priv->bitmap]; if (band >= 0) { - struct sk_buff_head *list = band2list(priv, band); + struct qdisc_skb_head *qh = band2list(priv, band); - return skb_peek(list); + return qh->head; } return NULL; @@ -569,7 +569,7 @@ static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt) struct pfifo_fast_priv *priv = qdisc_priv(qdisc); for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) - __skb_queue_head_init(band2list(priv, prio)); + qdisc_skb_head_init(band2list(priv, prio)); /* Can by-pass the queue discipline */ qdisc->flags |= TCQ_F_CAN_BYPASS; @@ -617,7 +617,8 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p); sch->padded = (char *) sch - (char *) p; } - skb_queue_head_init(&sch->q); + qdisc_skb_head_init(&sch->q); + spin_lock_init(&sch->q.lock); spin_lock_init(&sch->busylock); lockdep_set_class(&sch->busylock, |