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net_sched: convert tcf_hashinfo to hlist and use spinlock
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So that we don't need to play with singly linked list,
and since the code is not on hot path, we can use spinlock
instead of rwlock.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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WANG Cong authored and David S. Miller committed Dec 18, 2013
1 parent 369ba56 commit 89819dc
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Showing 3 changed files with 58 additions and 72 deletions.
16 changes: 10 additions & 6 deletions include/net/act_api.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@
#include <net/pkt_sched.h>

struct tcf_common {
struct tcf_common *tcfc_next;
struct hlist_node tcfc_head;
u32 tcfc_index;
int tcfc_refcnt;
int tcfc_bindcnt;
Expand All @@ -22,7 +22,7 @@ struct tcf_common {
spinlock_t tcfc_lock;
struct rcu_head tcfc_rcu;
};
#define tcf_next common.tcfc_next
#define tcf_head common.tcfc_head
#define tcf_index common.tcfc_index
#define tcf_refcnt common.tcfc_refcnt
#define tcf_bindcnt common.tcfc_bindcnt
Expand All @@ -36,9 +36,9 @@ struct tcf_common {
#define tcf_rcu common.tcfc_rcu

struct tcf_hashinfo {
struct tcf_common **htab;
struct hlist_head *htab;
unsigned int hmask;
rwlock_t lock;
spinlock_t lock;
};

static inline unsigned int tcf_hash(u32 index, unsigned int hmask)
Expand All @@ -48,12 +48,16 @@ static inline unsigned int tcf_hash(u32 index, unsigned int hmask)

static inline int tcf_hashinfo_init(struct tcf_hashinfo *hf, unsigned int mask)
{
rwlock_init(&hf->lock);
int i;

spin_lock_init(&hf->lock);
hf->hmask = mask;
hf->htab = kzalloc((mask + 1) * sizeof(struct tcf_common *),
hf->htab = kzalloc((mask + 1) * sizeof(struct hlist_head),
GFP_KERNEL);
if (!hf->htab)
return -ENOMEM;
for (i = 0; i < mask + 1; i++)
INIT_HLIST_HEAD(&hf->htab[i]);
return 0;
}

Expand Down
69 changes: 30 additions & 39 deletions net/sched/act_api.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,25 +29,16 @@

void tcf_hash_destroy(struct tcf_common *p, struct tcf_hashinfo *hinfo)
{
unsigned int h = tcf_hash(p->tcfc_index, hinfo->hmask);
struct tcf_common **p1p;

for (p1p = &hinfo->htab[h]; *p1p; p1p = &(*p1p)->tcfc_next) {
if (*p1p == p) {
write_lock_bh(&hinfo->lock);
*p1p = p->tcfc_next;
write_unlock_bh(&hinfo->lock);
gen_kill_estimator(&p->tcfc_bstats,
&p->tcfc_rate_est);
/*
* gen_estimator est_timer() might access p->tcfc_lock
* or bstats, wait a RCU grace period before freeing p
*/
kfree_rcu(p, tcfc_rcu);
return;
}
}
WARN_ON(1);
spin_lock_bh(&hinfo->lock);
hlist_del(&p->tcfc_head);
spin_unlock_bh(&hinfo->lock);
gen_kill_estimator(&p->tcfc_bstats,
&p->tcfc_rate_est);
/*
* gen_estimator est_timer() might access p->tcfc_lock
* or bstats, wait a RCU grace period before freeing p
*/
kfree_rcu(p, tcfc_rcu);
}
EXPORT_SYMBOL(tcf_hash_destroy);

Expand All @@ -73,18 +64,19 @@ EXPORT_SYMBOL(tcf_hash_release);
static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb,
struct tc_action *a, struct tcf_hashinfo *hinfo)
{
struct hlist_head *head;
struct tcf_common *p;
int err = 0, index = -1, i = 0, s_i = 0, n_i = 0;
struct nlattr *nest;

read_lock_bh(&hinfo->lock);
spin_lock_bh(&hinfo->lock);

s_i = cb->args[0];

for (i = 0; i < (hinfo->hmask + 1); i++) {
p = hinfo->htab[tcf_hash(i, hinfo->hmask)];
head = &hinfo->htab[tcf_hash(i, hinfo->hmask)];

for (; p; p = p->tcfc_next) {
hlist_for_each_entry_rcu(p, head, tcfc_head) {
index++;
if (index < s_i)
continue;
Expand All @@ -107,7 +99,7 @@ static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb,
}
}
done:
read_unlock_bh(&hinfo->lock);
spin_unlock_bh(&hinfo->lock);
if (n_i)
cb->args[0] += n_i;
return n_i;
Expand All @@ -120,7 +112,9 @@ static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb,
static int tcf_del_walker(struct sk_buff *skb, struct tc_action *a,
struct tcf_hashinfo *hinfo)
{
struct tcf_common *p, *s_p;
struct hlist_head *head;
struct hlist_node *n;
struct tcf_common *p;
struct nlattr *nest;
int i = 0, n_i = 0;

Expand All @@ -130,14 +124,11 @@ static int tcf_del_walker(struct sk_buff *skb, struct tc_action *a,
if (nla_put_string(skb, TCA_KIND, a->ops->kind))
goto nla_put_failure;
for (i = 0; i < (hinfo->hmask + 1); i++) {
p = hinfo->htab[tcf_hash(i, hinfo->hmask)];

while (p != NULL) {
s_p = p->tcfc_next;
head = &hinfo->htab[tcf_hash(i, hinfo->hmask)];
hlist_for_each_entry_safe(p, n, head, tcfc_head) {
if (ACT_P_DELETED == tcf_hash_release(p, 0, hinfo))
module_put(a->ops->owner);
n_i++;
p = s_p;
}
}
if (nla_put_u32(skb, TCA_FCNT, n_i))
Expand Down Expand Up @@ -168,15 +159,15 @@ EXPORT_SYMBOL(tcf_generic_walker);

struct tcf_common *tcf_hash_lookup(u32 index, struct tcf_hashinfo *hinfo)
{
struct tcf_common *p;
struct tcf_common *p = NULL;
struct hlist_head *head;

read_lock_bh(&hinfo->lock);
for (p = hinfo->htab[tcf_hash(index, hinfo->hmask)]; p;
p = p->tcfc_next) {
spin_lock_bh(&hinfo->lock);
head = &hinfo->htab[tcf_hash(index, hinfo->hmask)];
hlist_for_each_entry_rcu(p, head, tcfc_head)
if (p->tcfc_index == index)
break;
}
read_unlock_bh(&hinfo->lock);
spin_unlock_bh(&hinfo->lock);

return p;
}
Expand Down Expand Up @@ -236,6 +227,7 @@ struct tcf_common *tcf_hash_create(u32 index, struct nlattr *est,
p->tcfc_bindcnt = 1;

spin_lock_init(&p->tcfc_lock);
INIT_HLIST_NODE(&p->tcfc_head);
p->tcfc_index = index ? index : tcf_hash_new_index(idx_gen, hinfo);
p->tcfc_tm.install = jiffies;
p->tcfc_tm.lastuse = jiffies;
Expand All @@ -257,10 +249,9 @@ void tcf_hash_insert(struct tcf_common *p, struct tcf_hashinfo *hinfo)
{
unsigned int h = tcf_hash(p->tcfc_index, hinfo->hmask);

write_lock_bh(&hinfo->lock);
p->tcfc_next = hinfo->htab[h];
hinfo->htab[h] = p;
write_unlock_bh(&hinfo->lock);
spin_lock_bh(&hinfo->lock);
hlist_add_head(&p->tcfc_head, &hinfo->htab[h]);
spin_unlock_bh(&hinfo->lock);
}
EXPORT_SYMBOL(tcf_hash_insert);

Expand Down
45 changes: 18 additions & 27 deletions net/sched/act_police.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -60,18 +60,19 @@ struct tc_police_compat {
static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *cb,
int type, struct tc_action *a)
{
struct hlist_head *head;
struct tcf_common *p;
int err = 0, index = -1, i = 0, s_i = 0, n_i = 0;
struct nlattr *nest;

read_lock_bh(&police_hash_info.lock);
spin_lock_bh(&police_hash_info.lock);

s_i = cb->args[0];

for (i = 0; i < (POL_TAB_MASK + 1); i++) {
p = police_hash_info.htab[tcf_hash(i, POL_TAB_MASK)];
head = &police_hash_info.htab[tcf_hash(i, POL_TAB_MASK)];

for (; p; p = p->tcfc_next) {
hlist_for_each_entry_rcu(p, head, tcfc_head) {
index++;
if (index < s_i)
continue;
Expand All @@ -94,7 +95,7 @@ static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *c
}
}
done:
read_unlock_bh(&police_hash_info.lock);
spin_unlock_bh(&police_hash_info.lock);
if (n_i)
cb->args[0] += n_i;
return n_i;
Expand All @@ -106,25 +107,16 @@ static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *c

static void tcf_police_destroy(struct tcf_police *p)
{
unsigned int h = tcf_hash(p->tcf_index, POL_TAB_MASK);
struct tcf_common **p1p;

for (p1p = &police_hash_info.htab[h]; *p1p; p1p = &(*p1p)->tcfc_next) {
if (*p1p == &p->common) {
write_lock_bh(&police_hash_info.lock);
*p1p = p->tcf_next;
write_unlock_bh(&police_hash_info.lock);
gen_kill_estimator(&p->tcf_bstats,
&p->tcf_rate_est);
/*
* gen_estimator est_timer() might access p->tcf_lock
* or bstats, wait a RCU grace period before freeing p
*/
kfree_rcu(p, tcf_rcu);
return;
}
}
WARN_ON(1);
spin_lock_bh(&police_hash_info.lock);
hlist_del(&p->tcf_head);
spin_unlock_bh(&police_hash_info.lock);
gen_kill_estimator(&p->tcf_bstats,
&p->tcf_rate_est);
/*
* gen_estimator est_timer() might access p->tcf_lock
* or bstats, wait a RCU grace period before freeing p
*/
kfree_rcu(p, tcf_rcu);
}

static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
Expand Down Expand Up @@ -259,10 +251,9 @@ static int tcf_act_police_locate(struct net *net, struct nlattr *nla,
police->tcf_index = parm->index ? parm->index :
tcf_hash_new_index(&police_idx_gen, &police_hash_info);
h = tcf_hash(police->tcf_index, POL_TAB_MASK);
write_lock_bh(&police_hash_info.lock);
police->tcf_next = police_hash_info.htab[h];
police_hash_info.htab[h] = &police->common;
write_unlock_bh(&police_hash_info.lock);
spin_lock_bh(&police_hash_info.lock);
hlist_add_head(&police->tcf_head, &police_hash_info.htab[h]);
spin_unlock_bh(&police_hash_info.lock);

a->priv = police;
return ret;
Expand Down

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