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net: convert TCP/DCCP ehash rwlocks to spinlocks

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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>
This commit is contained in:
Eric Dumazet 2008-11-20 20:39:09 -08:00 committed by David S. Miller
parent b8c26a33c8
commit 9db66bdcc8
5 changed files with 41 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
include/net/inet_hashtables.h
View File

@ -116,7 +116,7 @@ struct inet_hashinfo {
* 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 @@ static inline struct inet_ehash_bucket *inet_ehash_bucket(
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 @@ static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
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 @@ static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
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

21
net/ipv4/inet_hashtables.c
View File

@ -271,13 +271,12 @@ static int __inet_check_established(struct inet_timewait_death_row *death_row,
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 @@ unique:
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 @@ unique:
return 0;
not_unique:
write_unlock(lock);
spin_unlock(lock);
return -EADDRNOTAVAIL;
}
@ -340,7 +339,7 @@ void __inet_hash_nolisten(struct sock *sk)
{
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 @@ void __inet_hash_nolisten(struct sock *sk)
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 @@ void inet_unhash(struct sock *sk)
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);

22
net/ipv4/inet_timewait_sock.c
View File

@ -20,16 +20,16 @@ static void __inet_twsk_kill(struct inet_timewait_sock *tw,
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 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
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 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
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 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
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 @@ void inet_twsk_purge(struct net *net, struct inet_hashinfo *hashinfo,
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 @@ restart:
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();
}

12
net/ipv4/tcp_ipv4.c
View File

@ -1970,13 +1970,13 @@ static void *established_get_first(struct seq_file *seq)
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 @@ static void *established_get_first(struct seq_file *seq)
rc = tw;
goto out;
}
read_unlock_bh(lock);
spin_unlock_bh(lock);
st->state = TCP_SEQ_STATE_ESTABLISHED;
}
out:
@ -2023,7 +2023,7 @@ get_tw:
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 @@ get_tw:
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 @@ static void tcp_seq_stop(struct seq_file *seq, void *v)
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;
}
}

15
net/ipv6/inet6_hashtables.c
View File

@ -38,14 +38,14 @@ void __inet6_hash(struct sock *sk)
} 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 @@ static int __inet6_check_established(struct inet_timewait_death_row *death_row,
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 @@ unique:
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 @@ unique:
return 0;
not_unique:
write_unlock(lock);
spin_unlock(lock);
return -EADDRNOTAVAIL;
}