diff options
| author | Yuchung Cheng <ycheng@google.com> | 2017-08-03 20:38:51 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-08-06 21:25:10 -0700 |
| commit | 4faf783998b8cb88294e9df89032f473f8771b78 (patch) | |
| tree | 0ad450f18cbf6c23f23e9f181a4d4ee5c6a99b7a /net/ipv4/tcp_cong.c | |
| parent | 10377ba7673d19e28d92846955d51f49acd25c35 (diff) | |
| download | linux-4faf783998b8cb88294e9df89032f473f8771b78.tar.gz | |
tcp: fix cwnd undo in Reno and HTCP congestion controls
Using ssthresh to revert cwnd is less reliable when ssthresh is bounded to 2 packets. This patch uses an existing variable in TCP "prior_cwnd" that snapshots the cwnd right before entering fast recovery and RTO recovery in Reno. This fixes the issue discussed in netdev thread: "A buggy behavior for Linux TCP Reno and HTCP" https://www.spinics.net/lists/netdev/msg444955.html Suggested-by: Neal Cardwell <ncardwell@google.com> Reported-by: Wei Sun <unlcsewsun@gmail.com> Signed-off-by: Yuchung Cheng <ncardwell@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_cong.c')
| -rw-r--r-- | net/ipv4/tcp_cong.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c index fde983f6376b..c2b174469645 100644 --- a/net/ipv4/tcp_cong.c +++ b/net/ipv4/tcp_cong.c @@ -456,7 +456,7 @@ u32 tcp_reno_undo_cwnd(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); - return max(tp->snd_cwnd, tp->snd_ssthresh << 1); + return max(tp->snd_cwnd, tp->prior_cwnd); } EXPORT_SYMBOL_GPL(tcp_reno_undo_cwnd); |