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netfilter: make xt_rateest hash table per net
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As suggested by Eric, we need to make the xt_rateest
hash table and its lock per netns to reduce lock
contentions.

Cc: Florian Westphal <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Pablo Neira Ayuso <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
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@congwang @ummakynes
congwang authored and ummakynes committed Mar 5, 2018
1 parent 0d7df90 commit 3427b2a
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Showing 3 changed files with 72 additions and 33 deletions.
4 changes: 2 additions & 2 deletions include/net/netfilter/xt_rateest.h
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ struct xt_rateest {
struct net_rate_estimator __rcu *rate_est;
};

struct xt_rateest *xt_rateest_lookup(const char *name);
void xt_rateest_put(struct xt_rateest *est);
struct xt_rateest *xt_rateest_lookup(struct net *net, const char *name);
void xt_rateest_put(struct net *net, struct xt_rateest *est);

#endif /* _XT_RATEEST_H */
91 changes: 65 additions & 26 deletions net/netfilter/xt_RATEEST.c
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Original file line number Diff line number Diff line change
Expand Up @@ -14,15 +14,21 @@
#include <linux/slab.h>
#include <net/gen_stats.h>
#include <net/netlink.h>
#include <net/netns/generic.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_RATEEST.h>
#include <net/netfilter/xt_rateest.h>

static DEFINE_MUTEX(xt_rateest_mutex);

#define RATEEST_HSIZE 16
static struct hlist_head rateest_hash[RATEEST_HSIZE] __read_mostly;

struct xt_rateest_net {
struct mutex hash_lock;
struct hlist_head hash[RATEEST_HSIZE];
};

static unsigned int xt_rateest_id;

static unsigned int jhash_rnd __read_mostly;

static unsigned int xt_rateest_hash(const char *name)
Expand All @@ -31,21 +37,23 @@ static unsigned int xt_rateest_hash(const char *name)
(RATEEST_HSIZE - 1);
}

static void xt_rateest_hash_insert(struct xt_rateest *est)
static void xt_rateest_hash_insert(struct xt_rateest_net *xn,
struct xt_rateest *est)
{
unsigned int h;

h = xt_rateest_hash(est->name);
hlist_add_head(&est->list, &rateest_hash[h]);
hlist_add_head(&est->list, &xn->hash[h]);
}

static struct xt_rateest *__xt_rateest_lookup(const char *name)
static struct xt_rateest *__xt_rateest_lookup(struct xt_rateest_net *xn,
const char *name)
{
struct xt_rateest *est;
unsigned int h;

h = xt_rateest_hash(name);
hlist_for_each_entry(est, &rateest_hash[h], list) {
hlist_for_each_entry(est, &xn->hash[h], list) {
if (strcmp(est->name, name) == 0) {
est->refcnt++;
return est;
Expand All @@ -55,20 +63,23 @@ static struct xt_rateest *__xt_rateest_lookup(const char *name)
return NULL;
}

struct xt_rateest *xt_rateest_lookup(const char *name)
struct xt_rateest *xt_rateest_lookup(struct net *net, const char *name)
{
struct xt_rateest_net *xn = net_generic(net, xt_rateest_id);
struct xt_rateest *est;

mutex_lock(&xt_rateest_mutex);
est = __xt_rateest_lookup(name);
mutex_unlock(&xt_rateest_mutex);
mutex_lock(&xn->hash_lock);
est = __xt_rateest_lookup(xn, name);
mutex_unlock(&xn->hash_lock);
return est;
}
EXPORT_SYMBOL_GPL(xt_rateest_lookup);

void xt_rateest_put(struct xt_rateest *est)
void xt_rateest_put(struct net *net, struct xt_rateest *est)
{
mutex_lock(&xt_rateest_mutex);
struct xt_rateest_net *xn = net_generic(net, xt_rateest_id);

mutex_lock(&xn->hash_lock);
if (--est->refcnt == 0) {
hlist_del(&est->list);
gen_kill_estimator(&est->rate_est);
Expand All @@ -78,7 +89,7 @@ void xt_rateest_put(struct xt_rateest *est)
*/
kfree_rcu(est, rcu);
}
mutex_unlock(&xt_rateest_mutex);
mutex_unlock(&xn->hash_lock);
}
EXPORT_SYMBOL_GPL(xt_rateest_put);

Expand All @@ -98,6 +109,7 @@ xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par)

static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
{
struct xt_rateest_net *xn = net_generic(par->net, xt_rateest_id);
struct xt_rateest_target_info *info = par->targinfo;
struct xt_rateest *est;
struct {
Expand All @@ -108,18 +120,18 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)

net_get_random_once(&jhash_rnd, sizeof(jhash_rnd));

mutex_lock(&xt_rateest_mutex);
est = __xt_rateest_lookup(info->name);
mutex_lock(&xn->hash_lock);
est = __xt_rateest_lookup(xn, info->name);
if (est) {
mutex_unlock(&xt_rateest_mutex);
mutex_unlock(&xn->hash_lock);
/*
* If estimator parameters are specified, they must match the
* existing estimator.
*/
if ((!info->interval && !info->ewma_log) ||
(info->interval != est->params.interval ||
info->ewma_log != est->params.ewma_log)) {
xt_rateest_put(est);
xt_rateest_put(par->net, est);
return -EINVAL;
}
info->est = est;
Expand Down Expand Up @@ -148,22 +160,22 @@ static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
goto err2;

info->est = est;
xt_rateest_hash_insert(est);
mutex_unlock(&xt_rateest_mutex);
xt_rateest_hash_insert(xn, est);
mutex_unlock(&xn->hash_lock);
return 0;

err2:
kfree(est);
err1:
mutex_unlock(&xt_rateest_mutex);
mutex_unlock(&xn->hash_lock);
return ret;
}

static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
{
struct xt_rateest_target_info *info = par->targinfo;

xt_rateest_put(info->est);
xt_rateest_put(par->net, info->est);
}

static struct xt_target xt_rateest_tg_reg __read_mostly = {
Expand All @@ -178,19 +190,46 @@ static struct xt_target xt_rateest_tg_reg __read_mostly = {
.me = THIS_MODULE,
};

static int __init xt_rateest_tg_init(void)
static __net_init int xt_rateest_net_init(struct net *net)
{
struct xt_rateest_net *xn = net_generic(net, xt_rateest_id);
int i;

mutex_init(&xn->hash_lock);
for (i = 0; i < ARRAY_SIZE(xn->hash); i++)
INIT_HLIST_HEAD(&xn->hash[i]);
return 0;
}

static void __net_exit xt_rateest_net_exit(struct net *net)
{
unsigned int i;
struct xt_rateest_net *xn = net_generic(net, xt_rateest_id);
int i;

for (i = 0; i < ARRAY_SIZE(xn->hash); i++)
WARN_ON_ONCE(!hlist_empty(&xn->hash[i]));
}

for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
INIT_HLIST_HEAD(&rateest_hash[i]);
static struct pernet_operations xt_rateest_net_ops = {
.init = xt_rateest_net_init,
.exit = xt_rateest_net_exit,
.id = &xt_rateest_id,
.size = sizeof(struct xt_rateest_net),
};

static int __init xt_rateest_tg_init(void)
{
int err = register_pernet_subsys(&xt_rateest_net_ops);

if (err)
return err;
return xt_register_target(&xt_rateest_tg_reg);
}

static void __exit xt_rateest_tg_fini(void)
{
xt_unregister_target(&xt_rateest_tg_reg);
unregister_pernet_subsys(&xt_rateest_net_ops);
}


Expand Down
10 changes: 5 additions & 5 deletions net/netfilter/xt_rateest.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -95,13 +95,13 @@ static int xt_rateest_mt_checkentry(const struct xt_mtchk_param *par)
}

ret = -ENOENT;
est1 = xt_rateest_lookup(info->name1);
est1 = xt_rateest_lookup(par->net, info->name1);
if (!est1)
goto err1;

est2 = NULL;
if (info->flags & XT_RATEEST_MATCH_REL) {
est2 = xt_rateest_lookup(info->name2);
est2 = xt_rateest_lookup(par->net, info->name2);
if (!est2)
goto err2;
}
Expand All @@ -111,7 +111,7 @@ static int xt_rateest_mt_checkentry(const struct xt_mtchk_param *par)
return 0;

err2:
xt_rateest_put(est1);
xt_rateest_put(par->net, est1);
err1:
return ret;
}
Expand All @@ -120,9 +120,9 @@ static void xt_rateest_mt_destroy(const struct xt_mtdtor_param *par)
{
struct xt_rateest_match_info *info = par->matchinfo;

xt_rateest_put(info->est1);
xt_rateest_put(par->net, info->est1);
if (info->est2)
xt_rateest_put(info->est2);
xt_rateest_put(par->net, info->est2);
}

static struct xt_match xt_rateest_mt_reg __read_mostly = {
Expand Down

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