From patchwork Tue Dec 9 10:21:18 2008 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [2/6] pkt_sched: sch_htb: Consider used jiffies in htb_dequeue() Date: Tue, 09 Dec 2008 00:21:18 -0000 From: Jarek Poplawski X-Patchwork-Id: 12908 Message-Id: <20081209102118.GB14862@ff.dom.local> To: David Miller Cc: Martin Devera , Patrick McHardy , netdev@vger.kernel.org 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). This patch charges jiffies globally, so we can skip this in htb_do_events(). Signed-off-by: Jarek Poplawski --- net/sched/sch_htb.c | 14 ++++++++++++-- 1 files changed, 12 insertions(+), 2 deletions(-) diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c index d6eb4a7..102866d 100644 --- a/net/sched/sch_htb.c +++ b/net/sched/sch_htb.c @@ -685,8 +685,11 @@ 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 (including above) */ - return q->now + 2 * PSCHED_TICKS_PER_SEC / HZ; + /* + * Too much load - let's continue on next jiffie. + * (Used jiffies are charged later.) + */ + return q->now + 1; } /* Returns class->node+prio from id-tree where classe's id is >= id. NULL @@ -845,6 +848,7 @@ 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 +861,7 @@ 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; @@ -889,6 +894,11 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch) } } sch->qstats.overlimits++; + /* charge used jiffies */ + start_at = jiffies - start_at; + if (start_at > 0) + next_event += start_at * PSCHED_TICKS_PER_SEC / HZ; + qdisc_watchdog_schedule(&q->watchdog, next_event); fin: return skb;