diff options
| author | Florian Westphal <fw@strlen.de> | 2016-11-21 14:18:38 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-11-21 13:20:17 -0500 |
| commit | e97991832a4ea4a5f47d65f068a4c966a2eb5730 (patch) | |
| tree | 870e5c09c37890d286872c9ae22382d6bf336b37 /net/ipv4/tcp_cong.c | |
| parent | 85f7e7508a1d288b513493196ef406c6c06134e1 (diff) | |
tcp: make undo_cwnd mandatory for congestion modules
The undo_cwnd fallback in the stack doubles cwnd based on ssthresh,
which un-does reno halving behaviour.
It seems more appropriate to let congctl algorithms pair .ssthresh
and .undo_cwnd properly. Add a 'tcp_reno_undo_cwnd' function and wire it
up for all congestion algorithms that used to rely on the fallback.
Cc: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
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 | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c index 1294af4e0127..38905ec5f508 100644 --- a/net/ipv4/tcp_cong.c +++ b/net/ipv4/tcp_cong.c @@ -68,8 +68,9 @@ int tcp_register_congestion_control(struct tcp_congestion_ops *ca) { int ret = 0; - /* all algorithms must implement ssthresh and cong_avoid ops */ - if (!ca->ssthresh || !(ca->cong_avoid || ca->cong_control)) { + /* all algorithms must implement these */ + if (!ca->ssthresh || !ca->undo_cwnd || + !(ca->cong_avoid || ca->cong_control)) { pr_err("%s does not implement required ops\n", ca->name); return -EINVAL; } @@ -441,10 +442,19 @@ u32 tcp_reno_ssthresh(struct sock *sk) } EXPORT_SYMBOL_GPL(tcp_reno_ssthresh); +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); +} +EXPORT_SYMBOL_GPL(tcp_reno_undo_cwnd); + struct tcp_congestion_ops tcp_reno = { .flags = TCP_CONG_NON_RESTRICTED, .name = "reno", .owner = THIS_MODULE, .ssthresh = tcp_reno_ssthresh, .cong_avoid = tcp_reno_cong_avoid, + .undo_cwnd = tcp_reno_undo_cwnd, }; |