diff options
| -rw-r--r-- | net/sched/sch_generic.c | 70 |
1 files changed, 48 insertions, 22 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 693df7ae33d..6f7aebd1407 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -406,18 +406,38 @@ static const u8 prio2band[TC_PRIO_MAX+1] = #define PFIFO_FAST_BANDS 3 -static inline struct sk_buff_head *prio2list(struct sk_buff *skb, - struct Qdisc *qdisc) +/* + * Private data for a pfifo_fast scheduler containing: + * - queues for the three band + * - bitmap indicating which of the bands contain skbs + */ +struct pfifo_fast_priv { + u32 bitmap; + struct sk_buff_head q[PFIFO_FAST_BANDS]; +}; + +/* + * Convert a bitmap to the first band number where an skb is queued, where: + * bitmap=0 means there are no skbs on any band. + * bitmap=1 means there is an skb on band 0. + * bitmap=7 means there are skbs on all 3 bands, etc. + */ +static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0}; + +static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv, + int band) { - struct sk_buff_head *list = qdisc_priv(qdisc); - return list + prio2band[skb->priority & TC_PRIO_MAX]; + return priv->q + band; } static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc) { - struct sk_buff_head *list = prio2list(skb, qdisc); + int band = prio2band[skb->priority & TC_PRIO_MAX]; + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); + struct sk_buff_head *list = band2list(priv, band); if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len) { + priv->bitmap |= (1 << band); qdisc->q.qlen++; return __qdisc_enqueue_tail(skb, qdisc, list); } @@ -427,14 +447,18 @@ static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc* qdisc) static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc) { - int prio; - struct sk_buff_head *list = qdisc_priv(qdisc); + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); + int band = bitmap2band[priv->bitmap]; - for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) { - if (!skb_queue_empty(list + prio)) { - qdisc->q.qlen--; - return __qdisc_dequeue_head(qdisc, list + prio); - } + if (likely(band >= 0)) { + struct sk_buff_head *list = band2list(priv, band); + struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list); + + qdisc->q.qlen--; + if (skb_queue_empty(list)) + priv->bitmap &= ~(1 << band); + + return skb; } return NULL; @@ -442,12 +466,13 @@ static struct sk_buff *pfifo_fast_dequeue(struct Qdisc* qdisc) static struct sk_buff *pfifo_fast_peek(struct Qdisc* qdisc) { - int prio; - struct sk_buff_head *list = qdisc_priv(qdisc); + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); + int band = bitmap2band[priv->bitmap]; + + if (band >= 0) { + struct sk_buff_head *list = band2list(priv, band); - for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) { - if (!skb_queue_empty(list + prio)) - return skb_peek(list + prio); + return skb_peek(list); } return NULL; @@ -456,11 +481,12 @@ static struct sk_buff *pfifo_fast_peek(struct Qdisc* qdisc) static void pfifo_fast_reset(struct Qdisc* qdisc) { int prio; - struct sk_buff_head *list = qdisc_priv(qdisc); + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) - __qdisc_reset_queue(qdisc, list + prio); + __qdisc_reset_queue(qdisc, band2list(priv, prio)); + priv->bitmap = 0; qdisc->qstats.backlog = 0; qdisc->q.qlen = 0; } @@ -480,17 +506,17 @@ nla_put_failure: static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt) { int prio; - struct sk_buff_head *list = qdisc_priv(qdisc); + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) - skb_queue_head_init(list + prio); + skb_queue_head_init(band2list(priv, prio)); return 0; } static struct Qdisc_ops pfifo_fast_ops __read_mostly = { .id = "pfifo_fast", - .priv_size = PFIFO_FAST_BANDS * sizeof(struct sk_buff_head), + .priv_size = sizeof(struct pfifo_fast_priv), .enqueue = pfifo_fast_enqueue, .dequeue = pfifo_fast_dequeue, .peek = pfifo_fast_peek, |