From: Neal Cardwell Date: Fri, 14 Jul 2017 21:49:21 +0000 (-0400) Subject: tcp_bbr: cut pacing rate only if filled pipe X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=4aea287e90dd61a48268ff2994b56f9799441b62;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git tcp_bbr: cut pacing rate only if filled pipe In bbr_set_pacing_rate(), which decides whether to cut the pacing rate, there was some code that considered exiting STARTUP to be equivalent to the notion of filling the pipe (i.e., bbr_full_bw_reached()). Specifically, as the code was structured, exiting STARTUP and going into PROBE_RTT could cause us to cut the pacing rate down to something silly and low, based on whatever bandwidth samples we've had so far, when it's possible that all of them have been small app-limited bandwidth samples that are not representative of the bandwidth available in the path. (The code was correct at the time it was written, but the state machine changed without this spot being adjusted correspondingly.) Fixes: 0f8782ea1497 ("tcp_bbr: add BBR congestion control") Signed-off-by: Neal Cardwell Signed-off-by: Yuchung Cheng Signed-off-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller --- diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c index dbcc9352a48f..743e97511dc8 100644 --- a/net/ipv4/tcp_bbr.c +++ b/net/ipv4/tcp_bbr.c @@ -220,12 +220,11 @@ static u64 bbr_rate_bytes_per_sec(struct sock *sk, u64 rate, int gain) */ static void bbr_set_pacing_rate(struct sock *sk, u32 bw, int gain) { - struct bbr *bbr = inet_csk_ca(sk); u64 rate = bw; rate = bbr_rate_bytes_per_sec(sk, rate, gain); rate = min_t(u64, rate, sk->sk_max_pacing_rate); - if (bbr->mode != BBR_STARTUP || rate > sk->sk_pacing_rate) + if (bbr_full_bw_reached(sk) || rate > sk->sk_pacing_rate) sk->sk_pacing_rate = rate; }