diff options
| author | Jon Maxwell <jmaxwell37@gmail.com> | 2018-07-19 11:14:44 +1000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-07-21 10:28:55 -0700 |
| commit | b701a99e431db784714c32fc6b68123045714679 (patch) | |
| tree | b5ec36b84c8ca0ed31442df0c3c8e456709fb570 /net | |
| parent | a7fa37703d495310819d0a6747e5b32362305374 (diff) | |
tcp: Add tcp_clamp_rto_to_user_timeout() helper to improve accuracy
Create the tcp_clamp_rto_to_user_timeout() helper routine. To calculate
the correct rto, so that the TCP_USER_TIMEOUT socket option is more
accurate. Taking suggestions and feedback into account from
Eric Dumazet, Neal Cardwell and David Laight. Due to the 1st commit we
can avoid the msecs_to_jiffies() and jiffies_to_msecs() dance.
Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_timer.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index d212f183dd2d..a242f8874629 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -36,6 +36,21 @@ u32 tcp_retransmit_stamp(const struct sock *sk) return start_ts; } +static u32 tcp_clamp_rto_to_user_timeout(const struct sock *sk) +{ + struct inet_connection_sock *icsk = inet_csk(sk); + u32 elapsed, start_ts; + + start_ts = tcp_retransmit_stamp(sk); + if (!icsk->icsk_user_timeout || !start_ts) + return icsk->icsk_rto; + elapsed = tcp_time_stamp(tcp_sk(sk)) - start_ts; + if (elapsed >= icsk->icsk_user_timeout) + return 1; /* user timeout has passed; fire ASAP */ + else + return min_t(u32, icsk->icsk_rto, msecs_to_jiffies(icsk->icsk_user_timeout - elapsed)); +} + /** * tcp_write_err() - close socket and save error info * @sk: The socket the error has appeared on. @@ -544,7 +559,8 @@ out_reset_timer: /* Use normal (exponential) backoff */ icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX); } - inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, TCP_RTO_MAX); + inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, + tcp_clamp_rto_to_user_timeout(sk), TCP_RTO_MAX); if (retransmits_timed_out(sk, net->ipv4.sysctl_tcp_retries1 + 1, 0)) __sk_dst_reset(sk); |