pkt_sched: sch_htb: Break all htb_do_events() after 2 jiffies

Currently htb_do_events() breaks events recounting for a level after 2
jiffies, but there is no reason to repeat this for next levels and
increase delays even more (with softirqs disabled). htb_dequeue_tree()
can add to this too, btw. In such a case q->now time is invalid anyway.

Thanks to Patrick McHardy for spotting an error around earlier version
of this patch.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 9ca8a26..2f0f0b0 100644 (file)
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -661,12 +661,13 @@ static void htb_charge_class(struct htb_sched *q, struct htb_class *cl,
  * next pending event (0 for no event in pq).
  * Note: Applied are events whose have cl->pq_key <= q->now.
  */
-static psched_time_t htb_do_events(struct htb_sched *q, int level)
+static psched_time_t htb_do_events(struct htb_sched *q, int level,
+                                  unsigned long start)
 {
        /* don't run for longer than 2 jiffies; 2 is used instead of
           1 to simplify things when jiffy is going to be incremented
           too soon */
-       unsigned long stop_at = jiffies + 2;
+       unsigned long stop_at = start + 2;
        while (time_before(jiffies, stop_at)) {
                struct htb_class *cl;
                long diff;
@@ -845,6 +846,7 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
        struct htb_sched *q = qdisc_priv(sch);
        int level;
        psched_time_t next_event;
+       unsigned long start_at;
 
        /* try to dequeue direct packets as high prio (!) to minimize cpu work */
        skb = __skb_dequeue(&q->direct_queue);
@@ -857,6 +859,7 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
        if (!sch->q.qlen)
                goto fin;
        q->now = psched_get_time();
+       start_at = jiffies;
 
        next_event = q->now + 5 * PSCHED_TICKS_PER_SEC;
 
@@ -866,7 +869,7 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
                psched_time_t event;
 
                if (q->now >= q->near_ev_cache[level]) {
-                       event = htb_do_events(q, level);
+                       event = htb_do_events(q, level, start_at);
                        if (!event)
                                event = q->now + PSCHED_TICKS_PER_SEC;
                        q->near_ev_cache[level] = event;