tcp_bbr: reset long-term bandwidth sampling on loss recovery undo

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 <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>
This commit is contained in:
Neal Cardwell 2017-12-07 12:43:32 -05:00 committed by David S. Miller
parent 2f6c498e4f
commit 600647d467

View File

@ -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;
}