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 /include/linux/tcp.h | |
| parent | 10377ba7673d19e28d92846955d51f49acd25c35 (diff) | |
| download | lwn-4faf783998b8cb88294e9df89032f473f8771b78.tar.gz lwn-4faf783998b8cb88294e9df89032f473f8771b78.zip | |
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 'include/linux/tcp.h')
| -rw-r--r-- | include/linux/tcp.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h index d7389ea36e10..267164a1d559 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -258,7 +258,7 @@ struct tcp_sock { u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */ u32 snd_cwnd_used; u32 snd_cwnd_stamp; - u32 prior_cwnd; /* Congestion window at start of Recovery. */ + u32 prior_cwnd; /* cwnd right before starting loss recovery */ u32 prr_delivered; /* Number of newly delivered packets to * receiver in Recovery. */ u32 prr_out; /* Total number of pkts sent during Recovery. */ |