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authorMartin Devera <devik@cdi.cz>2008-03-23 22:00:38 -0700
committerDavid S. Miller <davem@davemloft.net>2008-03-23 22:00:38 -0700
commit8f3ea33a5078a09eba12bfe57424507809367756 (patch)
tree4795705a232810311c72bc6dda939399653806f1
parent4b1b366721101f2f0d2350fbdccb679f7909cf57 (diff)
sch_htb: fix "too many events" situation
HTB is event driven algorithm and part of its work is to apply scheduled events at proper times. It tried to defend itself from livelock by processing only limited number of events per dequeue. Because of faster computers some users already hit this hardcoded limit. This patch limits processing up to 2 jiffies (why not 1 jiffie ? because it might stop prematurely when only fraction of jiffie remains). Signed-off-by: Martin Devera <devik@cdi.cz> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/sched/sch_htb.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 795c761ad99..66148cc4759 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -711,9 +711,11 @@ static void htb_charge_class(struct htb_sched *q, struct htb_class *cl,
*/
static psched_time_t htb_do_events(struct htb_sched *q, int level)
{
- int i;
-
- for (i = 0; i < 500; i++) {
+ /* 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;
+ while (time_before(jiffies, stop_at)) {
struct htb_class *cl;
long diff;
struct rb_node *p = rb_first(&q->wait_pq[level]);
@@ -731,9 +733,8 @@ static psched_time_t htb_do_events(struct htb_sched *q, int level)
if (cl->cmode != HTB_CAN_SEND)
htb_add_to_wait_tree(q, cl, diff);
}
- if (net_ratelimit())
- printk(KERN_WARNING "htb: too many events !\n");
- return q->now + PSCHED_TICKS_PER_SEC / 10;
+ /* too much load - let's continue on next jiffie */
+ return q->now + PSCHED_TICKS_PER_SEC / HZ;
}
/* Returns class->node+prio from id-tree where classe's id is >= id. NULL