net: convert TCP/DCCP ehash rwlocks to spinlocks
Now TCP & DCCP use RCU lookups, we can convert ehash rwlocks to spinlocks.
/proc/net/tcp and other seq_file 'readers' can safely be converted to 'writers'.
This should speedup writers, since spin_lock()/spin_unlock()
only use one atomic operation instead of two for write_lock()/write_unlock()
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 62d2dd0d..28b3ee3 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -116,7 +116,7 @@
* TIME_WAIT sockets use a separate chain (twchain).
*/
struct inet_ehash_bucket *ehash;
- rwlock_t *ehash_locks;
+ spinlock_t *ehash_locks;
unsigned int ehash_size;
unsigned int ehash_locks_mask;
@@ -152,7 +152,7 @@
return &hashinfo->ehash[hash & (hashinfo->ehash_size - 1)];
}
-static inline rwlock_t *inet_ehash_lockp(
+static inline spinlock_t *inet_ehash_lockp(
struct inet_hashinfo *hashinfo,
unsigned int hash)
{
@@ -177,16 +177,16 @@
size = 4096;
if (sizeof(rwlock_t) != 0) {
#ifdef CONFIG_NUMA
- if (size * sizeof(rwlock_t) > PAGE_SIZE)
- hashinfo->ehash_locks = vmalloc(size * sizeof(rwlock_t));
+ if (size * sizeof(spinlock_t) > PAGE_SIZE)
+ hashinfo->ehash_locks = vmalloc(size * sizeof(spinlock_t));
else
#endif
- hashinfo->ehash_locks = kmalloc(size * sizeof(rwlock_t),
+ hashinfo->ehash_locks = kmalloc(size * sizeof(spinlock_t),
GFP_KERNEL);
if (!hashinfo->ehash_locks)
return ENOMEM;
for (i = 0; i < size; i++)
- rwlock_init(&hashinfo->ehash_locks[i]);
+ spin_lock_init(&hashinfo->ehash_locks[i]);
}
hashinfo->ehash_locks_mask = size - 1;
return 0;
@@ -197,7 +197,7 @@
if (hashinfo->ehash_locks) {
#ifdef CONFIG_NUMA
unsigned int size = (hashinfo->ehash_locks_mask + 1) *
- sizeof(rwlock_t);
+ sizeof(spinlock_t);
if (size > PAGE_SIZE)
vfree(hashinfo->ehash_locks);
else
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 377d004..4c273a9 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -271,13 +271,12 @@
struct net *net = sock_net(sk);
unsigned int hash = inet_ehashfn(net, daddr, lport, saddr, inet->dport);
struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
- rwlock_t *lock = inet_ehash_lockp(hinfo, hash);
+ spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
struct sock *sk2;
const struct hlist_nulls_node *node;
struct inet_timewait_sock *tw;
- prefetch(head->chain.first);
- write_lock(lock);
+ spin_lock(lock);
/* Check TIME-WAIT sockets first. */
sk_nulls_for_each(sk2, node, &head->twchain) {
@@ -308,8 +307,8 @@
sk->sk_hash = hash;
WARN_ON(!sk_unhashed(sk));
__sk_nulls_add_node_rcu(sk, &head->chain);
+ spin_unlock(lock);
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
- write_unlock(lock);
if (twp) {
*twp = tw;
@@ -325,7 +324,7 @@
return 0;
not_unique:
- write_unlock(lock);
+ spin_unlock(lock);
return -EADDRNOTAVAIL;
}
@@ -340,7 +339,7 @@
{
struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
struct hlist_nulls_head *list;
- rwlock_t *lock;
+ spinlock_t *lock;
struct inet_ehash_bucket *head;
WARN_ON(!sk_unhashed(sk));
@@ -350,10 +349,10 @@
list = &head->chain;
lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
- write_lock(lock);
+ spin_lock(lock);
__sk_nulls_add_node_rcu(sk, list);
+ spin_unlock(lock);
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
- write_unlock(lock);
}
EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
@@ -402,12 +401,12 @@
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
spin_unlock_bh(&ilb->lock);
} else {
- rwlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+ spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
- write_lock_bh(lock);
+ spin_lock_bh(lock);
if (__sk_nulls_del_node_init_rcu(sk))
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
- write_unlock_bh(lock);
+ spin_unlock_bh(lock);
}
}
EXPORT_SYMBOL_GPL(inet_unhash);
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 6068995..8554d0e 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -20,16 +20,16 @@
struct inet_bind_hashbucket *bhead;
struct inet_bind_bucket *tb;
/* Unlink from established hashes. */
- rwlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);
+ spinlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash);
- write_lock(lock);
+ spin_lock(lock);
if (hlist_nulls_unhashed(&tw->tw_node)) {
- write_unlock(lock);
+ spin_unlock(lock);
return;
}
hlist_nulls_del_rcu(&tw->tw_node);
sk_nulls_node_init(&tw->tw_node);
- write_unlock(lock);
+ spin_unlock(lock);
/* Disassociate with bind bucket. */
bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), tw->tw_num,
@@ -76,7 +76,7 @@
const struct inet_sock *inet = inet_sk(sk);
const struct inet_connection_sock *icsk = inet_csk(sk);
struct inet_ehash_bucket *ehead = inet_ehash_bucket(hashinfo, sk->sk_hash);
- rwlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+ spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
struct inet_bind_hashbucket *bhead;
/* Step 1: Put TW into bind hash. Original socket stays there too.
Note, that any socket with inet->num != 0 MUST be bound in
@@ -90,7 +90,7 @@
inet_twsk_add_bind_node(tw, &tw->tw_tb->owners);
spin_unlock(&bhead->lock);
- write_lock(lock);
+ spin_lock(lock);
/*
* Step 2: Hash TW into TIMEWAIT chain.
@@ -104,7 +104,7 @@
if (__sk_nulls_del_node_init_rcu(sk))
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
- write_unlock(lock);
+ spin_unlock(lock);
}
EXPORT_SYMBOL_GPL(__inet_twsk_hashdance);
@@ -427,9 +427,9 @@
for (h = 0; h < (hashinfo->ehash_size); h++) {
struct inet_ehash_bucket *head =
inet_ehash_bucket(hashinfo, h);
- rwlock_t *lock = inet_ehash_lockp(hashinfo, h);
+ spinlock_t *lock = inet_ehash_lockp(hashinfo, h);
restart:
- write_lock(lock);
+ spin_lock(lock);
sk_nulls_for_each(sk, node, &head->twchain) {
tw = inet_twsk(sk);
@@ -438,13 +438,13 @@
continue;
atomic_inc(&tw->tw_refcnt);
- write_unlock(lock);
+ spin_unlock(lock);
inet_twsk_deschedule(tw, twdr);
inet_twsk_put(tw);
goto restart;
}
- write_unlock(lock);
+ spin_unlock(lock);
}
local_bh_enable();
}
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 330b08a..a81caa1 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1970,13 +1970,13 @@
struct sock *sk;
struct hlist_nulls_node *node;
struct inet_timewait_sock *tw;
- rwlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
+ spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket);
/* Lockless fast path for the common case of empty buckets */
if (empty_bucket(st))
continue;
- read_lock_bh(lock);
+ spin_lock_bh(lock);
sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) {
if (sk->sk_family != st->family ||
!net_eq(sock_net(sk), net)) {
@@ -1995,7 +1995,7 @@
rc = tw;
goto out;
}
- read_unlock_bh(lock);
+ spin_unlock_bh(lock);
st->state = TCP_SEQ_STATE_ESTABLISHED;
}
out:
@@ -2023,7 +2023,7 @@
cur = tw;
goto out;
}
- read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
+ spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
st->state = TCP_SEQ_STATE_ESTABLISHED;
/* Look for next non empty bucket */
@@ -2033,7 +2033,7 @@
if (st->bucket >= tcp_hashinfo.ehash_size)
return NULL;
- read_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
+ spin_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
sk = sk_nulls_head(&tcp_hashinfo.ehash[st->bucket].chain);
} else
sk = sk_nulls_next(sk);
@@ -2134,7 +2134,7 @@
case TCP_SEQ_STATE_TIME_WAIT:
case TCP_SEQ_STATE_ESTABLISHED:
if (v)
- read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
+ spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket));
break;
}
}
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index 21544b9..e0fd681 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -38,14 +38,14 @@
} else {
unsigned int hash;
struct hlist_nulls_head *list;
- rwlock_t *lock;
+ spinlock_t *lock;
sk->sk_hash = hash = inet6_sk_ehashfn(sk);
list = &inet_ehash_bucket(hashinfo, hash)->chain;
lock = inet_ehash_lockp(hashinfo, hash);
- write_lock(lock);
+ spin_lock(lock);
__sk_nulls_add_node_rcu(sk, list);
- write_unlock(lock);
+ spin_unlock(lock);
}
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
@@ -195,13 +195,12 @@
const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
inet->dport);
struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
- rwlock_t *lock = inet_ehash_lockp(hinfo, hash);
+ spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
struct sock *sk2;
const struct hlist_nulls_node *node;
struct inet_timewait_sock *tw;
- prefetch(head->chain.first);
- write_lock(lock);
+ spin_lock(lock);
/* Check TIME-WAIT sockets first. */
sk_nulls_for_each(sk2, node, &head->twchain) {
@@ -230,8 +229,8 @@
WARN_ON(!sk_unhashed(sk));
__sk_nulls_add_node_rcu(sk, &head->chain);
sk->sk_hash = hash;
+ spin_unlock(lock);
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
- write_unlock(lock);
if (twp != NULL) {
*twp = tw;
@@ -246,7 +245,7 @@
return 0;
not_unique:
- write_unlock(lock);
+ spin_unlock(lock);
return -EADDRNOTAVAIL;
}