diff options
| -rw-r--r-- | net/sched/sch_netem.c | 124 |
1 files changed, 36 insertions, 88 deletions
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index 5c0f0c2..48360f7 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -53,7 +53,6 @@ struct netem_sched_data { struct Qdisc *qdisc; - struct sk_buff_head delayed; struct timer_list timer; u32 latency; @@ -137,72 +136,6 @@ static long tabledist(unsigned long mu, long sigma, return x / NETEM_DIST_SCALE + (sigma / NETEM_DIST_SCALE) * t + mu; } -/* Put skb in the private delayed queue. */ -static int netem_delay(struct Qdisc *sch, struct sk_buff *skb) -{ - struct netem_sched_data *q = qdisc_priv(sch); - psched_tdiff_t td; - psched_time_t now; - - PSCHED_GET_TIME(now); - td = tabledist(q->latency, q->jitter, &q->delay_cor, q->delay_dist); - - /* Always queue at tail to keep packets in order */ - if (likely(q->delayed.qlen < q->limit)) { - struct netem_skb_cb *cb = (struct netem_skb_cb *)skb->cb; - - PSCHED_TADD2(now, td, cb->time_to_send); - - pr_debug("netem_delay: skb=%p now=%llu tosend=%llu\n", skb, - now, cb->time_to_send); - - __skb_queue_tail(&q->delayed, skb); - return NET_XMIT_SUCCESS; - } - - pr_debug("netem_delay: queue over limit %d\n", q->limit); - sch->qstats.overlimits++; - kfree_skb(skb); - return NET_XMIT_DROP; -} - -/* - * Move a packet that is ready to send from the delay holding - * list to the underlying qdisc. - */ -static int netem_run(struct Qdisc *sch) -{ - struct netem_sched_data *q = qdisc_priv(sch); - struct sk_buff *skb; - psched_time_t now; - - PSCHED_GET_TIME(now); - - skb = skb_peek(&q->delayed); - if (skb) { - const struct netem_skb_cb *cb - = (const struct netem_skb_cb *)skb->cb; - long delay - = PSCHED_US2JIFFIE(PSCHED_TDIFF(cb->time_to_send, now)); - pr_debug("netem_run: skb=%p delay=%ld\n", skb, delay); - - /* if more time remaining? */ - if (delay > 0) { - mod_timer(&q->timer, jiffies + delay); - return 1; - } - - __skb_unlink(skb, &q->delayed); - - if (q->qdisc->enqueue(skb, q->qdisc)) { - sch->q.qlen--; - sch->qstats.drops++; - } - } - - return 0; -} - /* * Insert one skb into qdisc. * Note: parent depends on return value to account for queue length. @@ -212,6 +145,7 @@ static int netem_run(struct Qdisc *sch) static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch) { struct netem_sched_data *q = qdisc_priv(sch); + struct netem_skb_cb *cb = (struct netem_skb_cb *)skb->cb; struct sk_buff *skb2; int ret; int count = 1; @@ -246,18 +180,24 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch) q->duplicate = dupsave; } - /* If doing simple delay then gap == 0 so all packets - * go into the delayed holding queue - * otherwise if doing out of order only "1 out of gap" - * packets will be delayed. + /* + * Do re-ordering by putting one out of N packets at the front + * of the queue. + * gap == 0 is special case for no-reordering. */ - if (q->counter < q->gap) { + if (q->gap == 0 || q->counter != q->gap) { + psched_time_t now; + PSCHED_GET_TIME(now); + PSCHED_TADD2(now, + tabledist(q->latency, q->jitter, &q->delay_cor, q->delay_dist), + cb->time_to_send); + ++q->counter; ret = q->qdisc->enqueue(skb, q->qdisc); } else { q->counter = 0; - ret = netem_delay(sch, skb); - netem_run(sch); + PSCHED_GET_TIME(cb->time_to_send); + ret = q->qdisc->ops->requeue(skb, q->qdisc); } if (likely(ret == NET_XMIT_SUCCESS)) { @@ -301,22 +241,33 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch) { struct netem_sched_data *q = qdisc_priv(sch); struct sk_buff *skb; - int pending; - - pending = netem_run(sch); skb = q->qdisc->dequeue(q->qdisc); if (skb) { - pr_debug("netem_dequeue: return skb=%p\n", skb); - sch->q.qlen--; - sch->flags &= ~TCQ_F_THROTTLED; - } - else if (pending) { - pr_debug("netem_dequeue: throttling\n"); + const struct netem_skb_cb *cb + = (const struct netem_skb_cb *)skb->cb; + psched_time_t now; + long delay; + + /* if more time remaining? */ + PSCHED_GET_TIME(now); + delay = PSCHED_US2JIFFIE(PSCHED_TDIFF(cb->time_to_send, now)); + pr_debug("netem_run: skb=%p delay=%ld\n", skb, delay); + if (delay <= 0) { + pr_debug("netem_dequeue: return skb=%p\n", skb); + sch->q.qlen--; + sch->flags &= ~TCQ_F_THROTTLED; + return skb; + } + + mod_timer(&q->timer, jiffies + delay); sch->flags |= TCQ_F_THROTTLED; - } - return skb; + if (q->qdisc->ops->requeue(skb, q->qdisc) != 0) + sch->qstats.drops++; + } + + return NULL; } static void netem_watchdog(unsigned long arg) @@ -333,8 +284,6 @@ static void netem_reset(struct Qdisc *sch) struct netem_sched_data *q = qdisc_priv(sch); qdisc_reset(q->qdisc); - skb_queue_purge(&q->delayed); - sch->q.qlen = 0; sch->flags &= ~TCQ_F_THROTTLED; del_timer_sync(&q->timer); @@ -460,7 +409,6 @@ static int netem_init(struct Qdisc *sch, struct rtattr *opt) if (!opt) return -EINVAL; - skb_queue_head_init(&q->delayed); init_timer(&q->timer); q->timer.function = netem_watchdog; q->timer.data = (unsigned long) sch; |