Commit fd245a4a authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net_sched: move TCQ_F_THROTTLED flag 



In commit 37112105 (net: QDISC_STATE_RUNNING dont need atomic bit
ops) I moved QDISC_STATE_RUNNING flag to __state container, located in
the cache line containing qdisc lock and often dirtied fields.

I now move TCQ_F_THROTTLED bit too, so that we let first cache line read
mostly, and shared by all cpus. This should speedup HTB/CBQ for example.

Not using test_bit()/__clear_bit()/__test_and_set_bit allows to use an
"unsigned int" for __state container, reducing by 8 bytes Qdisc size.

Introduce helpers to hide implementation details.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
CC: Jesper Dangaard Brouer <hawk@diku.dk>
CC: Jarek Poplawski <jarkao2@gmail.com>
CC: Jamal Hadi Salim <hadi@cyberus.ca>
CC: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 817fb15d

include/net/sch_generic.h

+28 −10
Original line number Diff line number Diff line
@@ -31,7 +31,8 @@ enum qdisc_state_t { 
 * following bits are only changed while qdisc lock is held

 */

enum qdisc___state_t {

	__QDISC___STATE_RUNNING,

	__QDISC___STATE_RUNNING = 1,

	__QDISC___STATE_THROTTLED = 2,

};



struct qdisc_size_table {
@@ -46,10 +47,9 @@ struct Qdisc { 
	struct sk_buff *	(*dequeue)(struct Qdisc *dev);

	unsigned		flags;

#define TCQ_F_BUILTIN		1

#define TCQ_F_THROTTLED		2

#define TCQ_F_INGRESS		4

#define TCQ_F_CAN_BYPASS	8

#define TCQ_F_MQROOT		16

#define TCQ_F_INGRESS		2

#define TCQ_F_CAN_BYPASS	4

#define TCQ_F_MQROOT		8

#define TCQ_F_WARN_NONWC	(1 << 16)

	int			padded;

	struct Qdisc_ops	*ops;
@@ -78,25 +78,43 @@ struct Qdisc { 
	unsigned long		state;

	struct sk_buff_head	q;

	struct gnet_stats_basic_packed bstats;

	unsigned long		__state;

	unsigned int		__state;

	struct gnet_stats_queue	qstats;

	struct rcu_head		rcu_head;

	spinlock_t		busylock;

};



static inline bool qdisc_is_running(struct Qdisc *qdisc)

static inline bool qdisc_is_running(const struct Qdisc *qdisc)

{

	return test_bit(__QDISC___STATE_RUNNING, &qdisc->__state);

	return (qdisc->__state & __QDISC___STATE_RUNNING) ? true : false;

}



static inline bool qdisc_run_begin(struct Qdisc *qdisc)

{

	return !__test_and_set_bit(__QDISC___STATE_RUNNING, &qdisc->__state);

	if (qdisc_is_running(qdisc))

		return false;

	qdisc->__state |= __QDISC___STATE_RUNNING;

	return true;

}



static inline void qdisc_run_end(struct Qdisc *qdisc)

{

	__clear_bit(__QDISC___STATE_RUNNING, &qdisc->__state);

	qdisc->__state &= ~__QDISC___STATE_RUNNING;

}



static inline bool qdisc_is_throttled(const struct Qdisc *qdisc)

{

	return (qdisc->__state & __QDISC___STATE_THROTTLED) ? true : false;

}



static inline void qdisc_throttled(struct Qdisc *qdisc)

{

	qdisc->__state |= __QDISC___STATE_THROTTLED;

}



static inline void qdisc_unthrottled(struct Qdisc *qdisc)

{

	qdisc->__state &= ~__QDISC___STATE_THROTTLED;

}



struct Qdisc_class_ops {

net/sched/sch_api.c

+3 −3
Original line number Diff line number Diff line
@@ -473,7 +473,7 @@ static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer) 
	struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,

						 timer);



	wd->qdisc->flags &= ~TCQ_F_THROTTLED;

	qdisc_unthrottled(wd->qdisc);

	__netif_schedule(qdisc_root(wd->qdisc));



	return HRTIMER_NORESTART;
@@ -495,7 +495,7 @@ void qdisc_watchdog_schedule(struct qdisc_watchdog *wd, psched_time_t expires) 
		     &qdisc_root_sleeping(wd->qdisc)->state))

		return;



	wd->qdisc->flags |= TCQ_F_THROTTLED;

	qdisc_throttled(wd->qdisc);

	time = ktime_set(0, 0);

	time = ktime_add_ns(time, PSCHED_TICKS2NS(expires));

	hrtimer_start(&wd->timer, time, HRTIMER_MODE_ABS);
@@ -505,7 +505,7 @@ EXPORT_SYMBOL(qdisc_watchdog_schedule); 
void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)

{

	hrtimer_cancel(&wd->timer);

	wd->qdisc->flags &= ~TCQ_F_THROTTLED;

	qdisc_unthrottled(wd->qdisc);

}

EXPORT_SYMBOL(qdisc_watchdog_cancel);

net/sched/sch_cbq.c

+3 −3
Original line number Diff line number Diff line
@@ -351,7 +351,7 @@ cbq_mark_toplevel(struct cbq_sched_data *q, struct cbq_class *cl) 
{

	int toplevel = q->toplevel;



	if (toplevel > cl->level && !(cl->q->flags & TCQ_F_THROTTLED)) {

	if (toplevel > cl->level && !(qdisc_is_throttled(cl->q))) {

		psched_time_t now;

		psched_tdiff_t incr;
@@ -625,7 +625,7 @@ static enum hrtimer_restart cbq_undelay(struct hrtimer *timer) 
		hrtimer_start(&q->delay_timer, time, HRTIMER_MODE_ABS);

	}



	sch->flags &= ~TCQ_F_THROTTLED;

	qdisc_unthrottled(sch);

	__netif_schedule(qdisc_root(sch));

	return HRTIMER_NORESTART;

}
@@ -974,7 +974,7 @@ cbq_dequeue(struct Qdisc *sch) 
		skb = cbq_dequeue_1(sch);

		if (skb) {

			sch->q.qlen--;

			sch->flags &= ~TCQ_F_THROTTLED;

			qdisc_unthrottled(sch);

			return skb;

		}

net/sched/sch_hfsc.c

+1 −1
Original line number Diff line number Diff line
@@ -1664,7 +1664,7 @@ hfsc_dequeue(struct Qdisc *sch) 
		set_passive(cl);

	}



	sch->flags &= ~TCQ_F_THROTTLED;

	qdisc_unthrottled(sch);

	sch->q.qlen--;



	return skb;

net/sched/sch_htb.c

+2 −2
Original line number Diff line number Diff line
@@ -865,7 +865,7 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch) 
	/* try to dequeue direct packets as high prio (!) to minimize cpu work */

	skb = __skb_dequeue(&q->direct_queue);

	if (skb != NULL) {

		sch->flags &= ~TCQ_F_THROTTLED;

		qdisc_unthrottled(sch);

		sch->q.qlen--;

		return skb;

	}
@@ -901,7 +901,7 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch) 
			skb = htb_dequeue_tree(q, prio, level);

			if (likely(skb != NULL)) {

				sch->q.qlen--;

				sch->flags &= ~TCQ_F_THROTTLED;

				qdisc_unthrottled(sch);

				goto fin;

			}

		}

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