tcp: use RCU in __inet{6}_check_established()

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When __inet_hash_connect() has to try many 4-tuples before
finding an available one, we see a high spinlock cost from
__inet_check_established() and/or __inet6_check_established().

This patch adds an RCU lookup to avoid the spinlock
acquisition when the 4-tuple is found in the hash table.

Note that there are still spin_lock_bh() calls in
__inet_hash_connect() to protect inet_bind_hashbucket,
this will be fixed later in this series.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Tested-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250302124237.3913746-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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Eric Dumazet 2025-03-02 12:42:34 +00:00 • committed by Jakub Kicinski

parent 7ff1c88fc8

commit ae9d5b19b3

2 changed files with 32 additions and 6 deletions

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19

net/ipv4/inet_hashtables.c

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19

net/ipv6/inet6_hashtables.c

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