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Commit 1224736d authored by Jarek Poplawski's avatar Jarek Poplawski Committed by David S. Miller
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pkt_sched: sch_htb: Use workqueue to schedule after too many events. 



Patrick McHardy <kaber@trash.net> suggested using a workqueue instead
of hrtimers to trigger netif_schedule() when there is a problem with
setting exact time of this event: 'The differnce - yeah, it shouldn't
make much, mainly wake up the qdisc earlier (but not too early) after
"too many events" occured _and_ no further enqueue events wake up the
qdisc anyways.'

Signed-off-by: default avatarJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e82181de

net/sched/sch_htb.c

+21 −5
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#include <linux/list.h>

#include <linux/compiler.h>

#include <linux/rbtree.h>

#include <linux/workqueue.h>

#include <net/netlink.h>

#include <net/pkt_sched.h>
@@ -156,6 +157,7 @@ struct htb_sched { 


#define HTB_WARN_TOOMANYEVENTS	0x1

	unsigned int warned;	/* only one warning */

	struct work_struct work;

};



/* find class in global hash table using given handle */
@@ -659,7 +661,7 @@ static void htb_charge_class(struct htb_sched *q, struct htb_class *cl, 
 * htb_do_events - make mode changes to classes at the level

 *

 * Scans event queue for pending events and applies them. Returns time of

 * next pending event (0 for no event in pq).

 * next pending event (0 for no event in pq, q->now for too many events).

 * Note: Applied are events whose have cl->pq_key <= q->now.

 */

static psched_time_t htb_do_events(struct htb_sched *q, int level,
@@ -687,12 +689,14 @@ 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) */



	/* too much load - let's continue after a break for scheduling */

	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;



	return q->now;

}



/* Returns class->node+prio from id-tree where classe's id is >= id. NULL
@@ -892,7 +896,10 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch) 
		}

	}

	sch->qstats.overlimits++;

	if (likely(next_event > q->now))

		qdisc_watchdog_schedule(&q->watchdog, next_event);

	else

		schedule_work(&q->work);

fin:

	return skb;

}
@@ -962,6 +969,14 @@ static const struct nla_policy htb_policy[TCA_HTB_MAX + 1] = { 
	[TCA_HTB_RTAB]	= { .type = NLA_BINARY, .len = TC_RTAB_SIZE },

};



static void htb_work_func(struct work_struct *work)

{

	struct htb_sched *q = container_of(work, struct htb_sched, work);

	struct Qdisc *sch = q->watchdog.qdisc;



	__netif_schedule(qdisc_root(sch));

}



static int htb_init(struct Qdisc *sch, struct nlattr *opt)

{

	struct htb_sched *q = qdisc_priv(sch);
@@ -996,6 +1011,7 @@ static int htb_init(struct Qdisc *sch, struct nlattr *opt) 
		INIT_LIST_HEAD(q->drops + i);



	qdisc_watchdog_init(&q->watchdog, sch);

	INIT_WORK(&q->work, htb_work_func);

	skb_queue_head_init(&q->direct_queue);



	q->direct_qlen = qdisc_dev(sch)->tx_queue_len;
@@ -1188,7 +1204,6 @@ static void htb_destroy_class(struct Qdisc *sch, struct htb_class *cl) 
	kfree(cl);

}



/* always caled under BH & queue lock */

static void htb_destroy(struct Qdisc *sch)

{

	struct htb_sched *q = qdisc_priv(sch);
@@ -1196,6 +1211,7 @@ static void htb_destroy(struct Qdisc *sch) 
	struct htb_class *cl;

	unsigned int i;



	cancel_work_sync(&q->work);

	qdisc_watchdog_cancel(&q->watchdog);

	/* This line used to be after htb_destroy_class call below

	   and surprisingly it worked in 2.4. But it must precede it