Patchwork [7/6,resend] pkt_sched: sch_htb: Consider used jiffies in htb_do_events()

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Submitter Jarek Poplawski
Date Jan. 12, 2009, 10:16 a.m.
Message ID <20090112101613.GA5781@ff.dom.local>
Download mbox | patch
Permalink /patch/17907/
State Accepted
Delegated to: David Miller
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Comments

Jarek Poplawski - Jan. 12, 2009, 10:16 a.m.
(resend)

pkt_sched: sch_htb: Consider used jiffies in htb_do_events()

Next event time should consider jiffies used for recounting. Otherwise
qdisc_watchdog_schedule() triggers hrtimer immediately with the event
in the past, and may cause very high ksoftirqd cpu usage (if highres
is on).

There is also removed checking "event" for zero in htb_dequeue(): it's
always true in this place.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
---

 net/sched/sch_htb.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

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David Miller - Jan. 13, 2009, 5:54 a.m.
From: Jarek Poplawski <jarkao2@gmail.com>
Date: Mon, 12 Jan 2009 10:16:13 +0000

> pkt_sched: sch_htb: Consider used jiffies in htb_do_events()
> 
> Next event time should consider jiffies used for recounting. Otherwise
> qdisc_watchdog_schedule() triggers hrtimer immediately with the event
> in the past, and may cause very high ksoftirqd cpu usage (if highres
> is on).
> 
> There is also removed checking "event" for zero in htb_dequeue(): it's
> always true in this place.
> 
> Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>

Applied.
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Patch

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 5070643..9ca8a26 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -685,8 +685,8 @@  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);
 	}
-	/* too much load - let's continue on next jiffie */
-	return q->now + PSCHED_TICKS_PER_SEC / HZ;
+	/* too much load - let's continue on next jiffie (including above) */
+	return q->now + 2 * PSCHED_TICKS_PER_SEC / HZ;
 }
 
 /* Returns class->node+prio from id-tree where classe's id is >= id. NULL
@@ -873,7 +873,7 @@  static struct sk_buff *htb_dequeue(struct Qdisc *sch)
 		} else
 			event = q->near_ev_cache[level];
 
-		if (event && next_event > event)
+		if (next_event > event)
 			next_event = event;
 
 		m = ~q->row_mask[level];