[PATCH net-next 0/4] tcp: provide better locality for retransmit timer

[Eric Dumazet <edumazet@google.com>]

TCP stack uses three timers per flow, currently spread this way:

- sk->sk_timer : keepalive timer
- icsk->icsk_retransmit_timer : retransmit timer
- icsk->icsk_delack_timer : delayed ack timer

This series moves the retransmit timer to sk->sk_timer location,
to increase data locality in TX paths.

keepalive timers are not often used, this change should be neutral for them.

After the series we have following fields:

- sk->tcp_retransmit_timer : retransmit timer, in sock_write_tx group
- icsk->icsk_delack_timer : delayed ack timer
- icsk->icsk_keepalive_timer : keepalive timer

Moving icsk_delack_timer in a beter location would also be welcomed.

Eric Dumazet (4):
  tcp: rename icsk_timeout() to tcp_timeout_expires()
  net: move sk_dst_pending_confirm and sk_pacing_status to sock_read_tx
    group
  tcp: introduce icsk->icsk_keepalive_timer
  tcp: remove icsk->icsk_retransmit_timer

 .../net_cachelines/inet_connection_sock.rst   |  2 +-
 include/net/inet_connection_sock.h            | 20 ++++++++------
 include/net/sock.h                            | 13 ++++++---
 net/core/sock.c                               |  4 +--
 net/ipv4/inet_connection_sock.c               | 12 ++++-----
 net/ipv4/inet_diag.c                          |  8 +++---
 net/ipv4/tcp_ipv4.c                           |  8 +++---
 net/ipv4/tcp_timer.c                          | 23 ++++++++--------
 net/ipv6/tcp_ipv6.c                           |  8 +++---
 net/mptcp/protocol.c                          | 27 +++++++++----------
 net/mptcp/protocol.h                          |  2 +-
 .../selftests/bpf/progs/bpf_iter_tcp4.c       |  8 +++---
 .../selftests/bpf/progs/bpf_iter_tcp6.c       |  8 +++---
 13 files changed, 74 insertions(+), 69 deletions(-)

-- 
2.52.0.460.gd25c4c69ec-goog