From: Kevin Yang yyd@google.com
[ Upstream commit 5490b32dce6932ea7ee8e3b2f76db2957c92af6e ]
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 yyd@google.com Signed-off-by: Neal Cardwell ncardwell@google.com Reviewed-by: Yuchung Cheng ycheng@google.com Reviewed-by: Soheil Hassas Yeganeh soheil@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.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 5880015dee36..e99d6afb70ef 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) { @@ -304,6 +306,8 @@ 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); } }