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/mptcp/mptcp_diag.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/mptcp') diff --git a/net/mptcp/mptcp_diag.c b/net/mptcp/mptcp_diag.c index dbb6d876a203..7f9a71780437 100644 --- a/net/mptcp/mptcp_diag.c +++ b/net/mptcp/mptcp_diag.c @@ -83,13 +83,13 @@ static void mptcp_diag_dump_listeners(struct sk_buff *skb, struct netlink_callba struct net *net = sock_net(skb->sk); int i; - for (i = diag_ctx->l_slot; i < INET_LHTABLE_SIZE; i++) { + for (i = diag_ctx->l_slot; i <= tcp_hashinfo.lhash2_mask; i++) { struct inet_listen_hashbucket *ilb; struct hlist_nulls_node *node; struct sock *sk; int num = 0; - ilb = &tcp_hashinfo.listening_hash[i]; + ilb = &tcp_hashinfo.lhash2[i]; rcu_read_lock(); spin_lock(&ilb->lock); -- cgit v1.2.3