diff options
| author | Florian Westphal <fw@strlen.de> | 2016-11-21 14:18:37 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-11-21 13:20:17 -0500 |
| commit | 85f7e7508a1d288b513493196ef406c6c06134e1 (patch) | |
| tree | 46cb7e0ff05b6e059d2060fbf3ad28bbc11ddc1e /net/ipv4/tcp_highspeed.c | |
| parent | 2fcb58ab30deb63e49f238bf95d587740fab59c4 (diff) | |
| download | lwn-85f7e7508a1d288b513493196ef406c6c06134e1.tar.gz lwn-85f7e7508a1d288b513493196ef406c6c06134e1.zip | |
tcp: add cwnd_undo functions to various tcp cc algorithms
congestion control algorithms that do not halve cwnd in their .ssthresh
should provide a .cwnd_undo rather than rely on current fallback which
assumes reno halving (and thus doubles the cwnd).
All of these do 'something else' in their .ssthresh implementation, thus
store the cwnd on loss and provide .undo_cwnd to restore it again.
A followup patch will remove the fallback and all algorithms will
need to provide a .cwnd_undo function.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_highspeed.c')
| -rw-r--r-- | net/ipv4/tcp_highspeed.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/net/ipv4/tcp_highspeed.c b/net/ipv4/tcp_highspeed.c index db7842495a64..6d9879e93648 100644 --- a/net/ipv4/tcp_highspeed.c +++ b/net/ipv4/tcp_highspeed.c @@ -94,6 +94,7 @@ static const struct hstcp_aimd_val { struct hstcp { u32 ai; + u32 loss_cwnd; }; static void hstcp_init(struct sock *sk) @@ -150,16 +151,24 @@ static void hstcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) static u32 hstcp_ssthresh(struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); - const struct hstcp *ca = inet_csk_ca(sk); + struct hstcp *ca = inet_csk_ca(sk); + ca->loss_cwnd = tp->snd_cwnd; /* Do multiplicative decrease */ return max(tp->snd_cwnd - ((tp->snd_cwnd * hstcp_aimd_vals[ca->ai].md) >> 8), 2U); } +static u32 hstcp_cwnd_undo(struct sock *sk) +{ + const struct hstcp *ca = inet_csk_ca(sk); + + return max(tcp_sk(sk)->snd_cwnd, ca->loss_cwnd); +} static struct tcp_congestion_ops tcp_highspeed __read_mostly = { .init = hstcp_init, .ssthresh = hstcp_ssthresh, + .undo_cwnd = hstcp_cwnd_undo, .cong_avoid = hstcp_cong_avoid, .owner = THIS_MODULE, |