From 9db66bdcc83749affe61c61eb8ff3cf08f42afec Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 20 Nov 2008 20:39:09 -0800 Subject: 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 Signed-off-by: David S. Miller --- net/ipv4/inet_hashtables.c | 21 ++++++++++----------- net/ipv4/inet_timewait_sock.c | 22 +++++++++++----------- net/ipv4/tcp_ipv4.c | 12 ++++++------ 3 files changed, 27 insertions(+), 28 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 377d004e572..4c273a9981a 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -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); diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c index 60689951ecd..8554d0ea171 100644 --- a/net/ipv4/inet_timewait_sock.c +++ b/net/ipv4/inet_timewait_sock.c @@ -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(); } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 330b08a1227..a81caa1be0c 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -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; } } -- cgit v1.2.3-70-g09d2