diff options
| author | Neal Cardwell <ncardwell@google.com> | 2017-08-16 17:53:36 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-08-18 16:07:43 -0700 |
| commit | cdbeb633ca71a02b7b63bfeb94994bf4e1a0b894 (patch) | |
| tree | 96d187e3d5f38c8fcb9045fb1ff323ad8164b021 /net/ipv4 | |
| parent | bc3aae2bbac46dd894c89db5d5e98f7f0ef9e205 (diff) | |
tcp: when rearming RTO, if RTO time is in past then fire RTO ASAP
In some situations tcp_send_loss_probe() can realize that it's unable
to send a loss probe (TLP), and falls back to calling tcp_rearm_rto()
to schedule an RTO timer. In such cases, sometimes tcp_rearm_rto()
realizes that the RTO was eligible to fire immediately or at some
point in the past (delta_us <= 0). Previously in such cases
tcp_rearm_rto() was scheduling such "overdue" RTOs to happen at now +
icsk_rto, which caused needless delays of hundreds of milliseconds
(and non-linear behavior that made reproducible testing
difficult). This commit changes the logic to schedule "overdue" RTOs
ASAP, rather than at now + icsk_rto.
Fixes: 6ba8a3b19e76 ("tcp: Tail loss probe (TLP)")
Suggested-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp_input.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 53de1424c13c..bab7f0493098 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3009,8 +3009,7 @@ void tcp_rearm_rto(struct sock *sk) /* delta_us may not be positive if the socket is locked * when the retrans timer fires and is rescheduled. */ - if (delta_us > 0) - rto = usecs_to_jiffies(delta_us); + rto = usecs_to_jiffies(max_t(int, delta_us, 1)); } inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, rto, TCP_RTO_MAX); |