path: root/net/ipv4/tcp_yeah.c
diff options
authorFlorian Westphal <fw@strlen.de>2016-11-21 14:18:37 +0100
committerDavid S. Miller <davem@davemloft.net>2016-11-21 13:20:17 -0500
commit85f7e7508a1d288b513493196ef406c6c06134e1 (patch)
tree46cb7e0ff05b6e059d2060fbf3ad28bbc11ddc1e /net/ipv4/tcp_yeah.c
parentMerge branch 'bridge-igmpv3-mldv2-support' (diff)
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_yeah.c')
1 files changed, 10 insertions, 0 deletions
diff --git a/net/ipv4/tcp_yeah.c b/net/ipv4/tcp_yeah.c
index 9c5fc973267f..e6ff99c4bd3b 100644
--- a/net/ipv4/tcp_yeah.c
+++ b/net/ipv4/tcp_yeah.c
@@ -37,6 +37,7 @@ struct yeah {
u32 fast_count;
u32 pkts_acked;
+ u32 loss_cwnd;
static void tcp_yeah_init(struct sock *sk)
@@ -219,13 +220,22 @@ static u32 tcp_yeah_ssthresh(struct sock *sk)
yeah->fast_count = 0;
yeah->reno_count = max(yeah->reno_count>>1, 2U);
+ yeah->loss_cwnd = tp->snd_cwnd;
return max_t(int, tp->snd_cwnd - reduction, 2);
+static u32 tcp_yeah_cwnd_undo(struct sock *sk)
+ const struct yeah *yeah = inet_csk_ca(sk);
+ return max(tcp_sk(sk)->snd_cwnd, yeah->loss_cwnd);
static struct tcp_congestion_ops tcp_yeah __read_mostly = {
.init = tcp_yeah_init,
.ssthresh = tcp_yeah_ssthresh,
+ .undo_cwnd = tcp_yeah_cwnd_undo,
.cong_avoid = tcp_yeah_cong_avoid,
.set_state = tcp_vegas_state,
.cwnd_event = tcp_vegas_cwnd_event,