From 8f3ea33a5078a09eba12bfe57424507809367756 Mon Sep 17 00:00:00 2001 From: Martin Devera Date: Sun, 23 Mar 2008 22:00:38 -0700 Subject: 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 Signed-off-by: David S. Miller --- net/sched/sch_htb.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'net') diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c index 795c761ad99f..66148cc4759e 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 -- cgit v1.2.3-59-g8ed1b