forked from luck/tmp_suning_uos_patched
netlink: Convert netlink_lookup() to use RCU protected hash table
Heavy Netlink users such as Open vSwitch spend a considerable amount of time in netlink_lookup() due to the read-lock on nl_table_lock. Use of RCU relieves the lock contention. Makes use of the new resizable hash table to avoid locking on the lookup. The hash table will grow if entries exceeds 75% of table size up to a total table size of 64K. It will automatically shrink if usage falls below 30%. Also splits nl_table_lock into a separate mutex to protect hash table mutations and allow synchronize_rcu() to sleep while waiting for readers during expansion and shrinking. Before: 9.16% kpktgend_0 [openvswitch] [k] masked_flow_lookup 6.42% kpktgend_0 [pktgen] [k] mod_cur_headers 6.26% kpktgend_0 [pktgen] [k] pktgen_thread_worker 6.23% kpktgend_0 [kernel.kallsyms] [k] memset 4.79% kpktgend_0 [kernel.kallsyms] [k] netlink_lookup 4.37% kpktgend_0 [kernel.kallsyms] [k] memcpy 3.60% kpktgend_0 [openvswitch] [k] ovs_flow_extract 2.69% kpktgend_0 [kernel.kallsyms] [k] jhash2 After: 15.26% kpktgend_0 [openvswitch] [k] masked_flow_lookup 8.12% kpktgend_0 [pktgen] [k] pktgen_thread_worker 7.92% kpktgend_0 [pktgen] [k] mod_cur_headers 5.11% kpktgend_0 [kernel.kallsyms] [k] memset 4.11% kpktgend_0 [openvswitch] [k] ovs_flow_extract 4.06% kpktgend_0 [kernel.kallsyms] [k] _raw_spin_lock 3.90% kpktgend_0 [kernel.kallsyms] [k] jhash2 [...] 0.67% kpktgend_0 [kernel.kallsyms] [k] netlink_lookup Signed-off-by: Thomas Graf <tgraf@suug.ch> Reviewed-by: Nikolay Aleksandrov <nikolay@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Thomas Graf
David S. Miller
parent
7e1e77636e
commit
e341694e3e
|
|
@ -58,7 +58,9 @@
|
|||
#include <linux/mutex.h>
|
||||
#include <linux/vmalloc.h>
|
||||
#include <linux/if_arp.h>
|
||||
#include <linux/rhashtable.h>
|
||||
#include <asm/cacheflush.h>
|
||||
#include <linux/hash.h>
|
||||
|
||||
#include <net/net_namespace.h>
|
||||
#include <net/sock.h>
|
||||
|
|
@ -100,6 +102,18 @@ static atomic_t nl_table_users = ATOMIC_INIT(0);
|
|||
|
||||
#define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
|
||||
|
||||
/* Protects netlink socket hash table mutations */
|
||||
DEFINE_MUTEX(nl_sk_hash_lock);
|
||||
|
||||
static int lockdep_nl_sk_hash_is_held(void)
|
||||
{
|
||||
#ifdef CONFIG_LOCKDEP
|
||||
return (debug_locks) ? lockdep_is_held(&nl_sk_hash_lock) : 1;
|
||||
#else
|
||||
return 1;
|
||||
#endif
|
||||
}
|
||||
|
||||
static ATOMIC_NOTIFIER_HEAD(netlink_chain);
|
||||
|
||||
static DEFINE_SPINLOCK(netlink_tap_lock);
|
||||
|
|
@ -110,11 +124,6 @@ static inline u32 netlink_group_mask(u32 group)
|
|||
return group ? 1 << (group - 1) : 0;
|
||||
}
|
||||
|
||||
static inline struct hlist_head *nl_portid_hashfn(struct nl_portid_hash *hash, u32 portid)
|
||||
{
|
||||
return &hash->table[jhash_1word(portid, hash->rnd) & hash->mask];
|
||||
}
|
||||
|
||||
int netlink_add_tap(struct netlink_tap *nt)
|
||||
{
|
||||
if (unlikely(nt->dev->type != ARPHRD_NETLINK))
|
||||
|
|
@ -983,107 +992,50 @@ netlink_unlock_table(void)
|
|||
wake_up(&nl_table_wait);
|
||||
}
|
||||
|
||||
static bool netlink_compare(struct net *net, struct sock *sk)
|
||||
struct netlink_compare_arg
|
||||
{
|
||||
return net_eq(sock_net(sk), net);
|
||||
struct net *net;
|
||||
u32 portid;
|
||||
};
|
||||
|
||||
static bool netlink_compare(void *ptr, void *arg)
|
||||
{
|
||||
struct netlink_compare_arg *x = arg;
|
||||
struct sock *sk = ptr;
|
||||
|
||||
return nlk_sk(sk)->portid == x->portid &&
|
||||
net_eq(sock_net(sk), x->net);
|
||||
}
|
||||
|
||||
static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
|
||||
struct net *net)
|
||||
{
|
||||
struct netlink_compare_arg arg = {
|
||||
.net = net,
|
||||
.portid = portid,
|
||||
};
|
||||
u32 hash;
|
||||
|
||||
hash = rhashtable_hashfn(&table->hash, &portid, sizeof(portid));
|
||||
|
||||
return rhashtable_lookup_compare(&table->hash, hash,
|
||||
&netlink_compare, &arg);
|
||||
}
|
||||
|
||||
static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
|
||||
{
|
||||
struct netlink_table *table = &nl_table[protocol];
|
||||
struct nl_portid_hash *hash = &table->hash;
|
||||
struct hlist_head *head;
|
||||
struct sock *sk;
|
||||
|
||||
read_lock(&nl_table_lock);
|
||||
head = nl_portid_hashfn(hash, portid);
|
||||
sk_for_each(sk, head) {
|
||||
if (table->compare(net, sk) &&
|
||||
(nlk_sk(sk)->portid == portid)) {
|
||||
rcu_read_lock();
|
||||
sk = __netlink_lookup(table, portid, net);
|
||||
if (sk)
|
||||
sock_hold(sk);
|
||||
goto found;
|
||||
}
|
||||
}
|
||||
sk = NULL;
|
||||
found:
|
||||
read_unlock(&nl_table_lock);
|
||||
rcu_read_unlock();
|
||||
|
||||
return sk;
|
||||
}
|
||||
|
||||
static struct hlist_head *nl_portid_hash_zalloc(size_t size)
|
||||
{
|
||||
if (size <= PAGE_SIZE)
|
||||
return kzalloc(size, GFP_ATOMIC);
|
||||
else
|
||||
return (struct hlist_head *)
|
||||
__get_free_pages(GFP_ATOMIC | __GFP_ZERO,
|
||||
get_order(size));
|
||||
}
|
||||
|
||||
static void nl_portid_hash_free(struct hlist_head *table, size_t size)
|
||||
{
|
||||
if (size <= PAGE_SIZE)
|
||||
kfree(table);
|
||||
else
|
||||
free_pages((unsigned long)table, get_order(size));
|
||||
}
|
||||
|
||||
static int nl_portid_hash_rehash(struct nl_portid_hash *hash, int grow)
|
||||
{
|
||||
unsigned int omask, mask, shift;
|
||||
size_t osize, size;
|
||||
struct hlist_head *otable, *table;
|
||||
int i;
|
||||
|
||||
omask = mask = hash->mask;
|
||||
osize = size = (mask + 1) * sizeof(*table);
|
||||
shift = hash->shift;
|
||||
|
||||
if (grow) {
|
||||
if (++shift > hash->max_shift)
|
||||
return 0;
|
||||
mask = mask * 2 + 1;
|
||||
size *= 2;
|
||||
}
|
||||
|
||||
table = nl_portid_hash_zalloc(size);
|
||||
if (!table)
|
||||
return 0;
|
||||
|
||||
otable = hash->table;
|
||||
hash->table = table;
|
||||
hash->mask = mask;
|
||||
hash->shift = shift;
|
||||
get_random_bytes(&hash->rnd, sizeof(hash->rnd));
|
||||
|
||||
for (i = 0; i <= omask; i++) {
|
||||
struct sock *sk;
|
||||
struct hlist_node *tmp;
|
||||
|
||||
sk_for_each_safe(sk, tmp, &otable[i])
|
||||
__sk_add_node(sk, nl_portid_hashfn(hash, nlk_sk(sk)->portid));
|
||||
}
|
||||
|
||||
nl_portid_hash_free(otable, osize);
|
||||
hash->rehash_time = jiffies + 10 * 60 * HZ;
|
||||
return 1;
|
||||
}
|
||||
|
||||
static inline int nl_portid_hash_dilute(struct nl_portid_hash *hash, int len)
|
||||
{
|
||||
int avg = hash->entries >> hash->shift;
|
||||
|
||||
if (unlikely(avg > 1) && nl_portid_hash_rehash(hash, 1))
|
||||
return 1;
|
||||
|
||||
if (unlikely(len > avg) && time_after(jiffies, hash->rehash_time)) {
|
||||
nl_portid_hash_rehash(hash, 0);
|
||||
return 1;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct proto_ops netlink_ops;
|
||||
|
||||
static void
|
||||
|
|
@ -1113,22 +1065,10 @@ netlink_update_listeners(struct sock *sk)
|
|||
static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
|
||||
{
|
||||
struct netlink_table *table = &nl_table[sk->sk_protocol];
|
||||
struct nl_portid_hash *hash = &table->hash;
|
||||
struct hlist_head *head;
|
||||
int err = -EADDRINUSE;
|
||||
struct sock *osk;
|
||||
int len;
|
||||
|
||||
netlink_table_grab();
|
||||
head = nl_portid_hashfn(hash, portid);
|
||||
len = 0;
|
||||
sk_for_each(osk, head) {
|
||||
if (table->compare(net, osk) &&
|
||||
(nlk_sk(osk)->portid == portid))
|
||||
break;
|
||||
len++;
|
||||
}
|
||||
if (osk)
|
||||
mutex_lock(&nl_sk_hash_lock);
|
||||
if (__netlink_lookup(table, portid, net))
|
||||
goto err;
|
||||
|
||||
err = -EBUSY;
|
||||
|
|
@ -1136,26 +1076,31 @@ static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
|
|||
goto err;
|
||||
|
||||
err = -ENOMEM;
|
||||
if (BITS_PER_LONG > 32 && unlikely(hash->entries >= UINT_MAX))
|
||||
if (BITS_PER_LONG > 32 && unlikely(table->hash.nelems >= UINT_MAX))
|
||||
goto err;
|
||||
|
||||
if (len && nl_portid_hash_dilute(hash, len))
|
||||
head = nl_portid_hashfn(hash, portid);
|
||||
hash->entries++;
|
||||
nlk_sk(sk)->portid = portid;
|
||||
sk_add_node(sk, head);
|
||||
sock_hold(sk);
|
||||
rhashtable_insert(&table->hash, &nlk_sk(sk)->node, GFP_KERNEL);
|
||||
err = 0;
|
||||
|
||||
err:
|
||||
netlink_table_ungrab();
|
||||
mutex_unlock(&nl_sk_hash_lock);
|
||||
return err;
|
||||
}
|
||||
|
||||
static void netlink_remove(struct sock *sk)
|
||||
{
|
||||
struct netlink_table *table;
|
||||
|
||||
mutex_lock(&nl_sk_hash_lock);
|
||||
table = &nl_table[sk->sk_protocol];
|
||||
if (rhashtable_remove(&table->hash, &nlk_sk(sk)->node, GFP_KERNEL)) {
|
||||
WARN_ON(atomic_read(&sk->sk_refcnt) == 1);
|
||||
__sock_put(sk);
|
||||
}
|
||||
mutex_unlock(&nl_sk_hash_lock);
|
||||
|
||||
netlink_table_grab();
|
||||
if (sk_del_node_init(sk))
|
||||
nl_table[sk->sk_protocol].hash.entries--;
|
||||
if (nlk_sk(sk)->subscriptions)
|
||||
__sk_del_bind_node(sk);
|
||||
netlink_table_ungrab();
|
||||
|
|
@ -1311,6 +1256,9 @@ static int netlink_release(struct socket *sock)
|
|||
}
|
||||
netlink_table_ungrab();
|
||||
|
||||
/* Wait for readers to complete */
|
||||
synchronize_net();
|
||||
|
||||
kfree(nlk->groups);
|
||||
nlk->groups = NULL;
|
||||
|
||||
|
|
@ -1326,30 +1274,22 @@ static int netlink_autobind(struct socket *sock)
|
|||
struct sock *sk = sock->sk;
|
||||
struct net *net = sock_net(sk);
|
||||
struct netlink_table *table = &nl_table[sk->sk_protocol];
|
||||
struct nl_portid_hash *hash = &table->hash;
|
||||
struct hlist_head *head;
|
||||
struct sock *osk;
|
||||
s32 portid = task_tgid_vnr(current);
|
||||
int err;
|
||||
static s32 rover = -4097;
|
||||
|
||||
retry:
|
||||
cond_resched();
|
||||
netlink_table_grab();
|
||||
head = nl_portid_hashfn(hash, portid);
|
||||
sk_for_each(osk, head) {
|
||||
if (!table->compare(net, osk))
|
||||
continue;
|
||||
if (nlk_sk(osk)->portid == portid) {
|
||||
rcu_read_lock();
|
||||
if (__netlink_lookup(table, portid, net)) {
|
||||
/* Bind collision, search negative portid values. */
|
||||
portid = rover--;
|
||||
if (rover > -4097)
|
||||
rover = -4097;
|
||||
netlink_table_ungrab();
|
||||
rcu_read_unlock();
|
||||
goto retry;
|
||||
}
|
||||
}
|
||||
netlink_table_ungrab();
|
||||
rcu_read_unlock();
|
||||
|
||||
err = netlink_insert(sk, net, portid);
|
||||
if (err == -EADDRINUSE)
|
||||
|
|
@ -2953,14 +2893,18 @@ static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
|
|||
{
|
||||
struct nl_seq_iter *iter = seq->private;
|
||||
int i, j;
|
||||
struct netlink_sock *nlk;
|
||||
struct sock *s;
|
||||
loff_t off = 0;
|
||||
|
||||
for (i = 0; i < MAX_LINKS; i++) {
|
||||
struct nl_portid_hash *hash = &nl_table[i].hash;
|
||||
struct rhashtable *ht = &nl_table[i].hash;
|
||||
const struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
|
||||
|
||||
for (j = 0; j < tbl->size; j++) {
|
||||
rht_for_each_entry_rcu(nlk, tbl->buckets[j], node) {
|
||||
s = (struct sock *)nlk;
|
||||
|
||||
for (j = 0; j <= hash->mask; j++) {
|
||||
sk_for_each(s, &hash->table[j]) {
|
||||
if (sock_net(s) != seq_file_net(seq))
|
||||
continue;
|
||||
if (off == pos) {
|
||||
|
|
@ -2976,15 +2920,14 @@ static struct sock *netlink_seq_socket_idx(struct seq_file *seq, loff_t pos)
|
|||
}
|
||||
|
||||
static void *netlink_seq_start(struct seq_file *seq, loff_t *pos)
|
||||
__acquires(nl_table_lock)
|
||||
{
|
||||
read_lock(&nl_table_lock);
|
||||
rcu_read_lock();
|
||||
return *pos ? netlink_seq_socket_idx(seq, *pos - 1) : SEQ_START_TOKEN;
|
||||
}
|
||||
|
||||
static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
|
||||
{
|
||||
struct sock *s;
|
||||
struct netlink_sock *nlk;
|
||||
struct nl_seq_iter *iter;
|
||||
struct net *net;
|
||||
int i, j;
|
||||
|
|
@ -2996,28 +2939,26 @@ static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
|
|||
|
||||
net = seq_file_net(seq);
|
||||
iter = seq->private;
|
||||
s = v;
|
||||
do {
|
||||
s = sk_next(s);
|
||||
} while (s && !nl_table[s->sk_protocol].compare(net, s));
|
||||
if (s)
|
||||
return s;
|
||||
nlk = v;
|
||||
|
||||
rht_for_each_entry_rcu(nlk, nlk->node.next, node)
|
||||
if (net_eq(sock_net((struct sock *)nlk), net))
|
||||
return nlk;
|
||||
|
||||
i = iter->link;
|
||||
j = iter->hash_idx + 1;
|
||||
|
||||
do {
|
||||
struct nl_portid_hash *hash = &nl_table[i].hash;
|
||||
struct rhashtable *ht = &nl_table[i].hash;
|
||||
const struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
|
||||
|
||||
for (; j <= hash->mask; j++) {
|
||||
s = sk_head(&hash->table[j]);
|
||||
|
||||
while (s && !nl_table[s->sk_protocol].compare(net, s))
|
||||
s = sk_next(s);
|
||||
if (s) {
|
||||
for (; j < tbl->size; j++) {
|
||||
rht_for_each_entry_rcu(nlk, tbl->buckets[j], node) {
|
||||
if (net_eq(sock_net((struct sock *)nlk), net)) {
|
||||
iter->link = i;
|
||||
iter->hash_idx = j;
|
||||
return s;
|
||||
return nlk;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
|
@ -3028,9 +2969,8 @@ static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos)
|
|||
}
|
||||
|
||||
static void netlink_seq_stop(struct seq_file *seq, void *v)
|
||||
__releases(nl_table_lock)
|
||||
{
|
||||
read_unlock(&nl_table_lock);
|
||||
rcu_read_unlock();
|
||||
}
|
||||
|
||||
|
||||
|
|
@ -3168,9 +3108,17 @@ static struct pernet_operations __net_initdata netlink_net_ops = {
|
|||
static int __init netlink_proto_init(void)
|
||||
{
|
||||
int i;
|
||||
unsigned long limit;
|
||||
unsigned int order;
|
||||
int err = proto_register(&netlink_proto, 0);
|
||||
struct rhashtable_params ht_params = {
|
||||
.head_offset = offsetof(struct netlink_sock, node),
|
||||
.key_offset = offsetof(struct netlink_sock, portid),
|
||||
.key_len = sizeof(u32), /* portid */
|
||||
.hashfn = arch_fast_hash,
|
||||
.max_shift = 16, /* 64K */
|
||||
.grow_decision = rht_grow_above_75,
|
||||
.shrink_decision = rht_shrink_below_30,
|
||||
.mutex_is_held = lockdep_nl_sk_hash_is_held,
|
||||
};
|
||||
|
||||
if (err != 0)
|
||||
goto out;
|
||||
|
|
@ -3181,32 +3129,13 @@ static int __init netlink_proto_init(void)
|
|||
if (!nl_table)
|
||||
goto panic;
|
||||
|
||||
if (totalram_pages >= (128 * 1024))
|
||||
limit = totalram_pages >> (21 - PAGE_SHIFT);
|
||||
else
|
||||
limit = totalram_pages >> (23 - PAGE_SHIFT);
|
||||
|
||||
order = get_bitmask_order(limit) - 1 + PAGE_SHIFT;
|
||||
limit = (1UL << order) / sizeof(struct hlist_head);
|
||||
order = get_bitmask_order(min(limit, (unsigned long)UINT_MAX)) - 1;
|
||||
|
||||
for (i = 0; i < MAX_LINKS; i++) {
|
||||
struct nl_portid_hash *hash = &nl_table[i].hash;
|
||||
|
||||
hash->table = nl_portid_hash_zalloc(1 * sizeof(*hash->table));
|
||||
if (!hash->table) {
|
||||
while (i-- > 0)
|
||||
nl_portid_hash_free(nl_table[i].hash.table,
|
||||
1 * sizeof(*hash->table));
|
||||
if (rhashtable_init(&nl_table[i].hash, &ht_params) < 0) {
|
||||
while (--i > 0)
|
||||
rhashtable_destroy(&nl_table[i].hash);
|
||||
kfree(nl_table);
|
||||
goto panic;
|
||||
}
|
||||
hash->max_shift = order;
|
||||
hash->shift = 0;
|
||||
hash->mask = 0;
|
||||
hash->rehash_time = jiffies;
|
||||
|
||||
nl_table[i].compare = netlink_compare;
|
||||
}
|
||||
|
||||
INIT_LIST_HEAD(&netlink_tap_all);
|
||||
|
|
|
|||
|
|
@ -1,6 +1,7 @@
|
|||
#ifndef _AF_NETLINK_H
|
||||
#define _AF_NETLINK_H
|
||||
|
||||
#include <linux/rhashtable.h>
|
||||
#include <net/sock.h>
|
||||
|
||||
#define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
|
||||
|
|
@ -47,6 +48,8 @@ struct netlink_sock {
|
|||
struct netlink_ring tx_ring;
|
||||
atomic_t mapped;
|
||||
#endif /* CONFIG_NETLINK_MMAP */
|
||||
|
||||
struct rhash_head node;
|
||||
};
|
||||
|
||||
static inline struct netlink_sock *nlk_sk(struct sock *sk)
|
||||
|
|
@ -54,21 +57,8 @@ static inline struct netlink_sock *nlk_sk(struct sock *sk)
|
|||
return container_of(sk, struct netlink_sock, sk);
|
||||
}
|
||||
|
||||
struct nl_portid_hash {
|
||||
struct hlist_head *table;
|
||||
unsigned long rehash_time;
|
||||
|
||||
unsigned int mask;
|
||||
unsigned int shift;
|
||||
|
||||
unsigned int entries;
|
||||
unsigned int max_shift;
|
||||
|
||||
u32 rnd;
|
||||
};
|
||||
|
||||
struct netlink_table {
|
||||
struct nl_portid_hash hash;
|
||||
struct rhashtable hash;
|
||||
struct hlist_head mc_list;
|
||||
struct listeners __rcu *listeners;
|
||||
unsigned int flags;
|
||||
|
|
|
|||
|
|
@ -4,6 +4,7 @@
|
|||
#include <linux/netlink.h>
|
||||
#include <linux/sock_diag.h>
|
||||
#include <linux/netlink_diag.h>
|
||||
#include <linux/rhashtable.h>
|
||||
|
||||
#include "af_netlink.h"
|
||||
|
||||
|
|
@ -101,16 +102,20 @@ static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
|
|||
int protocol, int s_num)
|
||||
{
|
||||
struct netlink_table *tbl = &nl_table[protocol];
|
||||
struct nl_portid_hash *hash = &tbl->hash;
|
||||
struct rhashtable *ht = &tbl->hash;
|
||||
const struct bucket_table *htbl = rht_dereference(ht->tbl, ht);
|
||||
struct net *net = sock_net(skb->sk);
|
||||
struct netlink_diag_req *req;
|
||||
struct netlink_sock *nlsk;
|
||||
struct sock *sk;
|
||||
int ret = 0, num = 0, i;
|
||||
|
||||
req = nlmsg_data(cb->nlh);
|
||||
|
||||
for (i = 0; i <= hash->mask; i++) {
|
||||
sk_for_each(sk, &hash->table[i]) {
|
||||
for (i = 0; i < htbl->size; i++) {
|
||||
rht_for_each_entry(nlsk, htbl->buckets[i], ht, node) {
|
||||
sk = (struct sock *)nlsk;
|
||||
|
||||
if (!net_eq(sock_net(sk), net))
|
||||
continue;
|
||||
if (num < s_num) {
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user