net: sched: convert qdisc linked list to hashtable

Convert the per-device linked list into a hashtable. The primary
motivation for this change is that currently, we're not tracking all the
qdiscs in hierarchy (e.g. excluding default qdiscs), as the lookup
performed over the linked list by qdisc_match_from_root() is rather
expensive.

The ultimate goal is to get rid of hidden qdiscs completely, which will
bring much more determinism in user experience.

Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jiri Kosina
2016-08-10 11:05:15 +02:00
committed by David S. Miller
parent e87a8f24c9
commit 59cc1f61f0
8 changed files with 30 additions and 18 deletions

View File

@@ -29,6 +29,7 @@
#include <linux/hrtimer.h>
#include <linux/lockdep.h>
#include <linux/slab.h>
#include <linux/hashtable.h>
#include <net/net_namespace.h>
#include <net/sock.h>
@@ -263,33 +264,33 @@ static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
root->handle == handle)
return root;
list_for_each_entry_rcu(q, &root->list, list) {
hash_for_each_possible_rcu(qdisc_dev(root)->qdisc_hash, q, hash, handle) {
if (q->handle == handle)
return q;
}
return NULL;
}
void qdisc_list_add(struct Qdisc *q)
void qdisc_hash_add(struct Qdisc *q)
{
if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
struct Qdisc *root = qdisc_dev(q)->qdisc;
WARN_ON_ONCE(root == &noop_qdisc);
ASSERT_RTNL();
list_add_tail_rcu(&q->list, &root->list);
hash_add_rcu(qdisc_dev(q)->qdisc_hash, &q->hash, q->handle);
}
}
EXPORT_SYMBOL(qdisc_list_add);
EXPORT_SYMBOL(qdisc_hash_add);
void qdisc_list_del(struct Qdisc *q)
void qdisc_hash_del(struct Qdisc *q)
{
if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
ASSERT_RTNL();
list_del_rcu(&q->list);
hash_del_rcu(&q->hash);
}
}
EXPORT_SYMBOL(qdisc_list_del);
EXPORT_SYMBOL(qdisc_hash_del);
struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
{
@@ -998,7 +999,7 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
goto err_out4;
}
qdisc_list_add(sch);
qdisc_hash_add(sch);
return sch;
}
@@ -1435,6 +1436,7 @@ static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
{
int ret = 0, q_idx = *q_idx_p;
struct Qdisc *q;
int b;
if (!root)
return 0;
@@ -1449,7 +1451,7 @@ static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
goto done;
q_idx++;
}
list_for_each_entry(q, &root->list, list) {
hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
if (q_idx < s_q_idx) {
q_idx++;
continue;
@@ -1765,6 +1767,7 @@ static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb,
int *t_p, int s_t)
{
struct Qdisc *q;
int b;
if (!root)
return 0;
@@ -1772,7 +1775,7 @@ static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb,
if (tc_dump_tclass_qdisc(root, skb, tcm, cb, t_p, s_t) < 0)
return -1;
list_for_each_entry(q, &root->list, list) {
hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
if (tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
return -1;
}