Commit d276055c authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net_sched: reduce fifo qdisc size 



Because of various alignements [SLUB / qdisc], we use 512 bytes of
memory for one {p|b}fifo qdisc, instead of 256 bytes on 64bit arches and
192 bytes on 32bit ones.

Move the "u32 limit" inside "struct Qdisc" (no impact on other qdiscs)

Change qdisc_alloc(), first trying a regular allocation before an
oversized one.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c53fa1ed

include/net/sch_generic.h

+1 −0
Original line number Diff line number Diff line
@@ -83,6 +83,7 @@ struct Qdisc { 
	struct gnet_stats_queue	qstats;

	struct rcu_head		rcu_head;

	spinlock_t		busylock;

	u32			limit;

};



static inline bool qdisc_is_running(const struct Qdisc *qdisc)

net/sched/sch_fifo.c

+11 −23
Original line number Diff line number Diff line
@@ -19,15 +19,9 @@ 


/* 1 band FIFO pseudo-"scheduler" */



struct fifo_sched_data {

	u32 limit;

};



static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch)

{

	struct fifo_sched_data *q = qdisc_priv(sch);



	if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= q->limit))

	if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= sch->limit))

		return qdisc_enqueue_tail(skb, sch);



	return qdisc_reshape_fail(skb, sch);
@@ -35,9 +29,7 @@ static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) 


static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch)

{

	struct fifo_sched_data *q = qdisc_priv(sch);



	if (likely(skb_queue_len(&sch->q) < q->limit))

	if (likely(skb_queue_len(&sch->q) < sch->limit))

		return qdisc_enqueue_tail(skb, sch);



	return qdisc_reshape_fail(skb, sch);
@@ -45,9 +37,7 @@ static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch) 


static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch)

{

	struct fifo_sched_data *q = qdisc_priv(sch);



	if (likely(skb_queue_len(&sch->q) < q->limit))

	if (likely(skb_queue_len(&sch->q) < sch->limit))

		return qdisc_enqueue_tail(skb, sch);



	/* queue full, remove one skb to fulfill the limit */
@@ -60,7 +50,6 @@ static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch) 


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

{

	struct fifo_sched_data *q = qdisc_priv(sch);

	bool bypass;

	bool is_bfifo = sch->ops == &bfifo_qdisc_ops;
@@ -70,20 +59,20 @@ static int fifo_init(struct Qdisc *sch, struct nlattr *opt) 
		if (is_bfifo)

			limit *= psched_mtu(qdisc_dev(sch));



		q->limit = limit;

		sch->limit = limit;

	} else {

		struct tc_fifo_qopt *ctl = nla_data(opt);



		if (nla_len(opt) < sizeof(*ctl))

			return -EINVAL;



		q->limit = ctl->limit;

		sch->limit = ctl->limit;

	}



	if (is_bfifo)

		bypass = q->limit >= psched_mtu(qdisc_dev(sch));

		bypass = sch->limit >= psched_mtu(qdisc_dev(sch));

	else

		bypass = q->limit >= 1;

		bypass = sch->limit >= 1;



	if (bypass)

		sch->flags |= TCQ_F_CAN_BYPASS;
@@ -94,8 +83,7 @@ static int fifo_init(struct Qdisc *sch, struct nlattr *opt) 


static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)

{

	struct fifo_sched_data *q = qdisc_priv(sch);

	struct tc_fifo_qopt opt = { .limit = q->limit };

	struct tc_fifo_qopt opt = { .limit = sch->limit };



	NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);

	return skb->len;
@@ -106,7 +94,7 @@ nla_put_failure: 


struct Qdisc_ops pfifo_qdisc_ops __read_mostly = {

	.id		=	"pfifo",

	.priv_size	=	sizeof(struct fifo_sched_data),

	.priv_size	=	0,

	.enqueue	=	pfifo_enqueue,

	.dequeue	=	qdisc_dequeue_head,

	.peek		=	qdisc_peek_head,
@@ -121,7 +109,7 @@ EXPORT_SYMBOL(pfifo_qdisc_ops); 


struct Qdisc_ops bfifo_qdisc_ops __read_mostly = {

	.id		=	"bfifo",

	.priv_size	=	sizeof(struct fifo_sched_data),

	.priv_size	=	0,

	.enqueue	=	bfifo_enqueue,

	.dequeue	=	qdisc_dequeue_head,

	.peek		=	qdisc_peek_head,
@@ -136,7 +124,7 @@ EXPORT_SYMBOL(bfifo_qdisc_ops); 


struct Qdisc_ops pfifo_head_drop_qdisc_ops __read_mostly = {

	.id		=	"pfifo_head_drop",

	.priv_size	=	sizeof(struct fifo_sched_data),

	.priv_size	=	0,

	.enqueue	=	pfifo_tail_enqueue,

	.dequeue	=	qdisc_dequeue_head,

	.peek		=	qdisc_peek_head,

net/sched/sch_generic.c

+11 −7
Original line number Diff line number Diff line
@@ -550,21 +550,25 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue, 
{

	void *p;

	struct Qdisc *sch;

	unsigned int size;

	unsigned int size = QDISC_ALIGN(sizeof(*sch)) + ops->priv_size;

	int err = -ENOBUFS;



	/* ensure that the Qdisc and the private data are 64-byte aligned */

	size = QDISC_ALIGN(sizeof(*sch));

	size += ops->priv_size + (QDISC_ALIGNTO - 1);



	p = kzalloc_node(size, GFP_KERNEL,

			 netdev_queue_numa_node_read(dev_queue));



	if (!p)

		goto errout;

	sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);

	/* if we got non aligned memory, ask more and do alignment ourself */

	if (sch != p) {

		kfree(p);

		p = kzalloc_node(size + QDISC_ALIGNTO - 1, GFP_KERNEL,

				 netdev_queue_numa_node_read(dev_queue));

		if (!p)

			goto errout;

		sch = (struct Qdisc *) QDISC_ALIGN((unsigned long) p);

		sch->padded = (char *) sch - (char *) p;



	}

	INIT_LIST_HEAD(&sch->list);

	skb_queue_head_init(&sch->q);

	spin_lock_init(&sch->busylock);

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