path: root/net/ipv4/tcp_bbr.c
diff options
authorNeal Cardwell <ncardwell@google.com>2017-12-07 12:43:31 -0500
committerDavid S. Miller <davem@davemloft.net>2017-12-08 13:27:43 -0500
commit2f6c498e4f15d27852c04ed46d804a39137ba364 (patch)
treeb6e959c086f40e706866f248110678ef5b889ff5 /net/ipv4/tcp_bbr.c
parenttcp_bbr: record "full bw reached" decision in new full_bw_reached bit (diff)
tcp_bbr: reset full pipe detection on loss recovery undo
Fix BBR so that upon notification of a loss recovery undo BBR resets the full pipe detection (STARTUP exit) state machine. Under high reordering, reordering events can be interpreted as loss. If the reordering and spurious loss estimates are high enough, this could previously cause BBR to spuriously estimate that the pipe is full. Since spurious loss recovery means that our overall sending will have slowed down spuriously, this commit gives a flow more time to probe robustly for bandwidth and decide the pipe is really full. Signed-off-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_bbr.c')
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c
index 3089c956b9f9..ab3ff14ea7f7 100644
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -874,6 +874,10 @@ static u32 bbr_sndbuf_expand(struct sock *sk)
static u32 bbr_undo_cwnd(struct sock *sk)
+ struct bbr *bbr = inet_csk_ca(sk);
+ bbr->full_bw = 0; /* spurious slow-down; reset full pipe detection */
+ bbr->full_bw_cnt = 0;
return tcp_sk(sk)->snd_cwnd;