From cae3873c5b3a4fcd9706fb461ff4e91bdf1f0120 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Wed, 11 May 2022 17:06:05 -0700 Subject: net: inet: Retire port only listening_hash The listen sk is currently stored in two hash tables, listening_hash (hashed by port) and lhash2 (hashed by port and address). After commit 0ee58dad5b06 ("net: tcp6: prefer listeners bound to an address") and commit d9fbc7f6431f ("net: tcp: prefer listeners bound to an address"), the TCP-SYN lookup fast path does not use listening_hash. The commit 05c0b35709c5 ("tcp: seq_file: Replace listening_hash with lhash2") also moved the seq_file (/proc/net/tcp) iteration usage from listening_hash to lhash2. There are still a few listening_hash usages left. One of them is inet_reuseport_add_sock() which uses the listening_hash to search a listen sk during the listen() system call. This turns out to be very slow on use cases that listen on many different VIPs at a popular port (e.g. 443). [ On top of the slowness in adding to the tail in the IPv6 case ]. The latter patch has a selftest to demonstrate this case. This patch takes this chance to move all remaining listening_hash usages to lhash2 and then retire listening_hash. Since most changes need to be done together, it is hard to cut the listening_hash to lhash2 switch into small patches. The changes in this patch is highlighted here for the review purpose. 1. Because of the listening_hash removal, lhash2 can use the sk->sk_nulls_node instead of the icsk->icsk_listen_portaddr_node. This will also keep the sk_unhashed() check to work as is after stop adding sk to listening_hash. The union is removed from inet_listen_hashbucket because only nulls_head is needed. 2. icsk->icsk_listen_portaddr_node and its helpers are removed. 3. The current lhash2 users needs to iterate with sk_nulls_node instead of icsk_listen_portaddr_node. One case is in the inet[6]_lhash2_lookup(). Another case is the seq_file iterator in tcp_ipv4.c. One thing to note is sk_nulls_next() is needed because the old inet_lhash2_for_each_icsk_continue() does a "next" first before iterating. 4. Move the remaining listening_hash usage to lhash2 inet_reuseport_add_sock() which this series is trying to improve. inet_diag.c and mptcp_diag.c are the final two remaining use cases and is moved to lhash2 now also. Signed-off-by: Martin KaFai Lau Reviewed-by: Eric Dumazet Signed-off-by: Jakub Kicinski --- net/ipv4/tcp_ipv4.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) (limited to 'net/ipv4/tcp_ipv4.c') diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 918816ec5dd4..218ad871c0e4 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2283,16 +2283,15 @@ static void *listening_get_first(struct seq_file *seq) st->offset = 0; for (; st->bucket <= tcp_hashinfo.lhash2_mask; st->bucket++) { struct inet_listen_hashbucket *ilb2; - struct inet_connection_sock *icsk; + struct hlist_nulls_node *node; struct sock *sk; ilb2 = &tcp_hashinfo.lhash2[st->bucket]; - if (hlist_empty(&ilb2->head)) + if (hlist_nulls_empty(&ilb2->nulls_head)) continue; spin_lock(&ilb2->lock); - inet_lhash2_for_each_icsk(icsk, &ilb2->head) { - sk = (struct sock *)icsk; + sk_nulls_for_each(sk, node, &ilb2->nulls_head) { if (seq_sk_match(seq, sk)) return sk; } @@ -2311,15 +2310,14 @@ static void *listening_get_next(struct seq_file *seq, void *cur) { struct tcp_iter_state *st = seq->private; struct inet_listen_hashbucket *ilb2; - struct inet_connection_sock *icsk; + struct hlist_nulls_node *node; struct sock *sk = cur; ++st->num; ++st->offset; - icsk = inet_csk(sk); - inet_lhash2_for_each_icsk_continue(icsk) { - sk = (struct sock *)icsk; + sk = sk_nulls_next(sk); + sk_nulls_for_each_from(sk, node) { if (seq_sk_match(seq, sk)) return sk; } @@ -2728,16 +2726,15 @@ static unsigned int bpf_iter_tcp_listening_batch(struct seq_file *seq, { struct bpf_tcp_iter_state *iter = seq->private; struct tcp_iter_state *st = &iter->state; - struct inet_connection_sock *icsk; + struct hlist_nulls_node *node; unsigned int expected = 1; struct sock *sk; sock_hold(start_sk); iter->batch[iter->end_sk++] = start_sk; - icsk = inet_csk(start_sk); - inet_lhash2_for_each_icsk_continue(icsk) { - sk = (struct sock *)icsk; + sk = sk_nulls_next(start_sk); + sk_nulls_for_each_from(sk, node) { if (seq_sk_match(seq, sk)) { if (iter->end_sk < iter->max_sk) { sock_hold(sk); -- cgit