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tcp: fix stretch ACK bugs in Yeah

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Change Yeah to properly handle stretch ACKs in additive
increase mode by passing in the count of ACKed packets
to tcp_cong_avoid_ai().

In addition, we re-implemented the scalable path using
tcp_cong_avoid_ai() and removed the pkts_acked variable.

Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Pengcheng Yang 2020-03-16 14:35:11 +08:00 committed by David S. Miller
parent ca04f5d4bb
commit fa4cb9eba3
1 changed files with 11 additions and 30 deletions
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41
net/ipv4/tcp_yeah.c
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@ -36,8 +36,6 @@ struct yeah {
u32 reno_count;
u32 fast_count;
u32 pkts_acked;
};
static void tcp_yeah_init(struct sock *sk)
@ -57,18 +55,6 @@ static void tcp_yeah_init(struct sock *sk)
tp->snd_cwnd_clamp = min_t(u32, tp->snd_cwnd_clamp, 0xffffffff/128);
}
static void tcp_yeah_pkts_acked(struct sock *sk,
const struct ack_sample *sample)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
struct yeah *yeah = inet_csk_ca(sk);
if (icsk->icsk_ca_state == TCP_CA_Open)
yeah->pkts_acked = sample->pkts_acked;
tcp_vegas_pkts_acked(sk, sample);
}
static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, u32 acked)
{
struct tcp_sock *tp = tcp_sk(sk);
@ -77,24 +63,19 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, u32 acked)
if (!tcp_is_cwnd_limited(sk))
return;
if (tcp_in_slow_start(tp))
tcp_slow_start(tp, acked);
if (tcp_in_slow_start(tp)) {
acked = tcp_slow_start(tp, acked);
if (!acked)
goto do_vegas;
}
else if (!yeah->doing_reno_now) {
if (!yeah->doing_reno_now) {
/* Scalable */
tp->snd_cwnd_cnt += yeah->pkts_acked;
if (tp->snd_cwnd_cnt > min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT)) {
if (tp->snd_cwnd < tp->snd_cwnd_clamp)
tp->snd_cwnd++;
tp->snd_cwnd_cnt = 0;
}
yeah->pkts_acked = 1;
tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT),
acked);
} else {
/* Reno */
tcp_cong_avoid_ai(tp, tp->snd_cwnd, 1);
tcp_cong_avoid_ai(tp, tp->snd_cwnd, acked);
}
/* The key players are v_vegas.beg_snd_una and v_beg_snd_nxt.
@ -118,7 +99,7 @@ static void tcp_yeah_cong_avoid(struct sock *sk, u32 ack, u32 acked)
* of bytes we send in an RTT is often less than our cwnd will allow.
* So we keep track of our cwnd separately, in v_beg_snd_cwnd.
*/
do_vegas:
if (after(ack, yeah->vegas.beg_snd_nxt)) {
/* We do the Vegas calculations only if we got enough RTT
* samples that we can be reasonably sure that we got
@ -232,7 +213,7 @@ static struct tcp_congestion_ops tcp_yeah __read_mostly = {
.set_state = tcp_vegas_state,
.cwnd_event = tcp_vegas_cwnd_event,
.get_info = tcp_vegas_get_info,
.pkts_acked = tcp_yeah_pkts_acked,
.pkts_acked = tcp_vegas_pkts_acked,
.owner = THIS_MODULE,
.name = "yeah",