pkt_sched: sch_htb: Warn on too many events.

Let's get some info on possible config problems. This patch brings
back an old warning, but is printed only once now.

With feedback from Patrick McHardy <kaber@trash.net>

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

net/sched/sch_htb.c

@@ -153,6 +153,9 @@ struct htb_sched {
 	int direct_qlen;	/* max qlen of above */
 
 	long direct_pkts;
+
+#define HTB_WARN_TOOMANYEVENTS	0x1
+	unsigned int warned;	/* only one warning */
 };
 
 /* find class in global hash table using given handle */
@@ -685,6 +688,10 @@ static psched_time_t htb_do_events(struct htb_sched *q, int level,
 			htb_add_to_wait_tree(q, cl, diff);
 	}
 	/* too much load - let's continue on next jiffie (including above) */
+	if (!(q->warned & HTB_WARN_TOOMANYEVENTS)) {
+		printk(KERN_WARNING "htb: too many events!\n");
+		q->warned |= HTB_WARN_TOOMANYEVENTS;
+	}
 	return q->now + 2 * PSCHED_TICKS_PER_SEC / HZ;
 }