From 95f30b336b944e3e418f825044b4793d9e9aac09 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 9 Feb 2007 15:44:52 -0800 Subject: [PATCH] [UDP]: UDP can use sk_hash to speedup lookups In a prior patch, I introduced a sk_hash field (__sk_common.skc_hash) to let tcp lookups use one cache line per unmatched entry instead of two. We can also use sk_hash to speedup UDP part as well. We store in sk_hash the hnum value, and use sk->sk_hash (same cache line than 'next' pointer), instead of inet->num (different cache line) Note : We still have a false sharing problem for SMP machines, because sock_hold(sock) dirties the cache line containing the 'next' pointer. Not counting the udp_hash_lock rwlock. (did someone mentioned RCU ? :) ) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/udp.c | 9 +++++---- net/ipv6/udp.c | 4 ++-- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 2a246de6a6..ce6c460343 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -120,7 +120,7 @@ static inline int __udp_lib_lport_inuse(__u16 num, struct hlist_head udptable[]) struct hlist_node *node; sk_for_each(sk, node, &udptable[num & (UDP_HTABLE_SIZE - 1)]) - if (inet_sk(sk)->num == num) + if (sk->sk_hash == num) return 1; return 0; } @@ -191,7 +191,7 @@ gotit: head = &udptable[snum & (UDP_HTABLE_SIZE - 1)]; sk_for_each(sk2, node, head) - if (inet_sk(sk2)->num == snum && + if (sk2->sk_hash == snum && sk2 != sk && (!sk2->sk_reuse || !sk->sk_reuse) && (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if @@ -200,6 +200,7 @@ gotit: goto fail; } inet_sk(sk)->num = snum; + sk->sk_hash = snum; if (sk_unhashed(sk)) { head = &udptable[snum & (UDP_HTABLE_SIZE - 1)]; sk_add_node(sk, head); @@ -247,7 +248,7 @@ static struct sock *__udp4_lib_lookup(__be32 saddr, __be16 sport, sk_for_each(sk, node, &udptable[hnum & (UDP_HTABLE_SIZE - 1)]) { struct inet_sock *inet = inet_sk(sk); - if (inet->num == hnum && !ipv6_only_sock(sk)) { + if (sk->sk_hash == hnum && !ipv6_only_sock(sk)) { int score = (sk->sk_family == PF_INET ? 1 : 0); if (inet->rcv_saddr) { if (inet->rcv_saddr != daddr) @@ -296,7 +297,7 @@ static inline struct sock *udp_v4_mcast_next(struct sock *sk, sk_for_each_from(s, node) { struct inet_sock *inet = inet_sk(s); - if (inet->num != hnum || + if (s->sk_hash != hnum || (inet->daddr && inet->daddr != rmt_addr) || (inet->dport != rmt_port && inet->dport) || (inet->rcv_saddr && inet->rcv_saddr != loc_addr) || diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index dbe2748db1..ccf2f4d196 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -71,7 +71,7 @@ static struct sock *__udp6_lib_lookup(struct in6_addr *saddr, __be16 sport, sk_for_each(sk, node, &udptable[hnum & (UDP_HTABLE_SIZE - 1)]) { struct inet_sock *inet = inet_sk(sk); - if (inet->num == hnum && sk->sk_family == PF_INET6) { + if (sk->sk_hash == hnum && sk->sk_family == PF_INET6) { struct ipv6_pinfo *np = inet6_sk(sk); int score = 0; if (inet->dport) { @@ -309,7 +309,7 @@ static struct sock *udp_v6_mcast_next(struct sock *sk, sk_for_each_from(s, node) { struct inet_sock *inet = inet_sk(s); - if (inet->num == num && s->sk_family == PF_INET6) { + if (s->sk_hash == num && s->sk_family == PF_INET6) { struct ipv6_pinfo *np = inet6_sk(s); if (inet->dport) { if (inet->dport != rmt_port) -- 2.39.5