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| author | Neal Cardwell <ncardwell@google.com> | 2017-08-17 00:53:36 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-08-30 11:19:21 +0300 |
| commit | 4e39b7409f3b852ae95e580207b4aec93965834c (patch) | |
| tree | d6837563a9c1aad79a7420945b68ffcbcaeed120 /net/ipv4/tcp_input.c | |
| parent | ece3ff173731fa87fec618fbf8734ca867eb8e42 (diff) | |
| download | linux-4e39b7409f3b852ae95e580207b4aec93965834c.tar.xz | |
tcp: when rearming RTO, if RTO time is in past then fire RTO ASAP
[ Upstream commit cdbeb633ca71a02b7b63bfeb94994bf4e1a0b894 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -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 f0dabd125c43..c4bbf704ff9c 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3028,8 +3028,7 @@ void tcp_rearm_rto(struct sock *sk) /* delta may not be positive if the socket is locked * when the retrans timer fires and is rescheduled. */ - if (delta > 0) - rto = delta; + rto = max(delta, 1); } inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, rto, TCP_RTO_MAX); |