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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: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2011-03-03 11:10:02 -08:00 committed by David S. Miller
parent c53fa1ed92
commit d276055c4e
3 changed files with 23 additions and 30 deletions
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1
include/net/sch_generic.h
View File

@ -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)

34
net/sched/sch_fifo.c
View File

@ -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,

18
net/sched/sch_generic.c
View File

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