path: root/net/ipv6/inet6_hashtables.c
diff options
authorEric Dumazet <dada1@cosmosbay.com>2007-11-07 02:40:20 -0800
committerDavid S. Miller <davem@sunset.davemloft.net>2007-11-07 04:15:11 -0800
commit230140cffa7feae90ad50bf259db1fa07674f3a7 (patch)
tree815472add31606423a508a17806b7884f0ab3e2e /net/ipv6/inet6_hashtables.c
parent[IPVS]: Synchronize closing of Connections (diff)
[INET]: Remove per bucket rwlock in tcp/dccp ehash table.
As done two years ago on IP route cache table (commit 22c047ccbc68fa8f3fa57f0e8f906479a062c426) , we can avoid using one lock per hash bucket for the huge TCP/DCCP hash tables. On a typical x86_64 platform, this saves about 2MB or 4MB of ram, for litle performance differences. (we hit a different cache line for the rwlock, but then the bucket cache line have a better sharing factor among cpus, since we dirty it less often). For netstat or ss commands that want a full scan of hash table, we perform fewer memory accesses. Using a 'small' table of hashed rwlocks should be more than enough to provide correct SMP concurrency between different buckets, without using too much memory. Sizing of this table depends on num_possible_cpus() and various CONFIG settings. This patch provides some locking abstraction that may ease a future work using a different model for TCP/DCCP table. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
1 files changed, 10 insertions, 9 deletions
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index d6f1026f1943..adc73adadfae 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -37,9 +37,8 @@ void __inet6_hash(struct inet_hashinfo *hashinfo,
} else {
unsigned int hash;
sk->sk_hash = hash = inet6_sk_ehashfn(sk);
- hash &= (hashinfo->ehash_size - 1);
- list = &hashinfo->ehash[hash].chain;
- lock = &hashinfo->ehash[hash].lock;
+ list = &inet_ehash_bucket(hashinfo, hash)->chain;
+ lock = inet_ehash_lockp(hashinfo, hash);
@@ -70,9 +69,10 @@ struct sock *__inet6_lookup_established(struct inet_hashinfo *hashinfo,
unsigned int hash = inet6_ehashfn(daddr, hnum, saddr, sport);
struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash);
+ rwlock_t *lock = inet_ehash_lockp(hashinfo, hash);
- read_lock(&head->lock);
+ read_lock(lock);
sk_for_each(sk, node, &head->chain) {
/* For IPV6 do the cheaper port and family tests first. */
if (INET6_MATCH(sk, hash, saddr, daddr, ports, dif))
@@ -92,12 +92,12 @@ struct sock *__inet6_lookup_established(struct inet_hashinfo *hashinfo,
goto hit;
- read_unlock(&head->lock);
+ read_unlock(lock);
return NULL;
- read_unlock(&head->lock);
+ read_unlock(lock);
return sk;
@@ -175,12 +175,13 @@ static int __inet6_check_established(struct inet_timewait_death_row *death_row,
const unsigned int hash = inet6_ehashfn(daddr, lport, saddr,
struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
+ rwlock_t *lock = inet_ehash_lockp(hinfo, hash);
struct sock *sk2;
const struct hlist_node *node;
struct inet_timewait_sock *tw;
- write_lock(&head->lock);
+ write_lock(lock);
/* Check TIME-WAIT sockets first. */
sk_for_each(sk2, node, &head->twchain) {
@@ -216,7 +217,7 @@ unique:
__sk_add_node(sk, &head->chain);
sk->sk_hash = hash;
- write_unlock(&head->lock);
+ write_unlock(lock);
if (twp != NULL) {
*twp = tw;
@@ -231,7 +232,7 @@ unique:
return 0;
- write_unlock(&head->lock);
+ write_unlock(lock);