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/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();
}