lkml.org 
[lkml]   [2020]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH RESEND net-next v2 5/5] tcp: fix stretch ACK bugs in Yeah
Date
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>
---
net/ipv4/tcp_yeah.c | 41 +++++++++++------------------------------
1 file changed, 11 insertions(+), 30 deletions(-)

diff --git a/net/ipv4/tcp_yeah.c b/net/ipv4/tcp_yeah.c
index e00570d..3bb4487 100644
--- a/net/ipv4/tcp_yeah.c
+++ b/net/ipv4/tcp_yeah.c
@@ -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 u32 tcp_yeah_ssthresh(struct sock *sk)
.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",
--
1.8.3.1
\
 
 \ /
  Last update: 2020-03-16 07:50    [W:0.074 / U:4.036 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site