This patch fix the case where BBR does not exit PROBE_RTT mode when
it restarts from idle. When BBR restarts from idle and if BBR is in
PROBE_RTT mode, BBR should check if it's time to exit PROBE_RTT. If
yes, then BBR should exit PROBE_RTT mode and restore the cwnd to its
full value.
Fixes: 0f8782ea1497 ("tcp_bbr: add BBR congestion control")
Signed-off-by: Kevin Yang <y...@google.com>
Signed-off-by: Neal Cardwell <ncardw...@google.com>
Reviewed-by: Yuchung Cheng <ych...@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soh...@google.com>
---
net/ipv4/tcp_bbr.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c
index fd7bccf36a263..1d4bdd3b5e4d0 100644
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -174,6 +174,8 @@ static const u32 bbr_lt_bw_diff = 4000 / 8;
/* If we estimate we're policed, use lt_bw for this many round trips: */
static const u32 bbr_lt_bw_max_rtts = 48;
+static void bbr_check_probe_rtt_done(struct sock *sk);
+
/* Do we estimate that STARTUP filled the pipe? */
static bool bbr_full_bw_reached(const struct sock *sk)
{
@@ -308,6 +310,8 @@ static void bbr_cwnd_event(struct sock *sk, enum
tcp_ca_event event)
*/
if (bbr->mode == BBR_PROBE_BW)
bbr_set_pacing_rate(sk, bbr_bw(sk), BBR_UNIT);
+ else if (bbr->mode == BBR_PROBE_RTT)
+ bbr_check_probe_rtt_done(sk);
}
}
--
2.18.0.1017.ga543ac7ca45-goog
