sk->sk_timer has been used for TCP keepalives.
Keepalive timers are not in fast path, we want to use sk->sk_timer
storage for retransmit timers, for better cache locality.
Create icsk->icsk_keepalive_timer and change keepalive
code to no longer use sk->sk_timer.
Added space is reclaimed in the following patch.
This includes changes to MPTCP, which was also using sk_timer.
Alias icsk->mptcp_tout_timer and icsk->icsk_keepalive_timer
for inet_sk_diag_fill() sake.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251124175013.1473655-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>