From c7e9d724785dc9b6a423bddc6b4fa6fb1368692f Mon Sep 17 00:00:00 2001 From: Neal Cardwell Date: Thu, 7 Dec 2017 12:43:32 -0500 Subject: [PATCH] tcp_bbr: reset long-term bandwidth sampling on loss recovery undo [ Upstream commit 600647d467c6d04b3954b41a6ee1795b5ae00550 ] Fix BBR so that upon notification of a loss recovery undo BBR resets long-term bandwidth sampling. Under high reordering, reordering events can be interpreted as loss. If the reordering and spurious loss estimates are high enough, this can cause BBR to spuriously estimate that we are seeing loss rates high enough to trigger long-term bandwidth estimation. To avoid that problem, this commit resets long-term bandwidth sampling on loss recovery undo events. Signed-off-by: Neal Cardwell Reviewed-by: Yuchung Cheng Acked-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_bbr.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c index ab3ff14ea7f7..8322f26e770e 100644 --- a/net/ipv4/tcp_bbr.c +++ b/net/ipv4/tcp_bbr.c @@ -878,6 +878,7 @@ static u32 bbr_undo_cwnd(struct sock *sk) bbr->full_bw = 0; /* spurious slow-down; reset full pipe detection */ bbr->full_bw_cnt = 0; + bbr_reset_lt_bw_sampling(sk); return tcp_sk(sk)->snd_cwnd; } -- 2.20.1