[PATCH RESEND net-next v2 3/5] tcp: stretch ACK fixes in Veno prep

From: Pengcheng Yang
Date: Mon Mar 16 2020 - 03:23:50 EST


No code logic has been changed in this patch.

Signed-off-by: Pengcheng Yang <yangpc@xxxxxxxxxx>
---
net/ipv4/tcp_veno.c | 44 +++++++++++++++++++++++---------------------
1 file changed, 23 insertions(+), 21 deletions(-)

diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c
index 3b36bb1..857491c 100644
--- a/net/ipv4/tcp_veno.c
+++ b/net/ipv4/tcp_veno.c
@@ -153,31 +153,33 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked)
veno->diff = (tp->snd_cwnd << V_PARAM_SHIFT) - target_cwnd;

if (tcp_in_slow_start(tp)) {
- /* Slow start. */
+ /* Slow start. */
tcp_slow_start(tp, acked);
+ goto done;
+ }
+
+ /* Congestion avoidance. */
+ if (veno->diff < beta) {
+ /* In the "non-congestive state", increase cwnd
+ * every rtt.
+ */
+ tcp_cong_avoid_ai(tp, tp->snd_cwnd, 1);
} else {
- /* Congestion avoidance. */
- if (veno->diff < beta) {
- /* In the "non-congestive state", increase cwnd
- * every rtt.
- */
- tcp_cong_avoid_ai(tp, tp->snd_cwnd, 1);
- } else {
- /* In the "congestive state", increase cwnd
- * every other rtt.
- */
- if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
- if (veno->inc &&
- tp->snd_cwnd < tp->snd_cwnd_clamp) {
- tp->snd_cwnd++;
- veno->inc = 0;
- } else
- veno->inc = 1;
- tp->snd_cwnd_cnt = 0;
+ /* In the "congestive state", increase cwnd
+ * every other rtt.
+ */
+ if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
+ if (veno->inc &&
+ tp->snd_cwnd < tp->snd_cwnd_clamp) {
+ tp->snd_cwnd++;
+ veno->inc = 0;
} else
- tp->snd_cwnd_cnt++;
- }
+ veno->inc = 1;
+ tp->snd_cwnd_cnt = 0;
+ } else
+ tp->snd_cwnd_cnt++;
}
+done:
if (tp->snd_cwnd < 2)
tp->snd_cwnd = 2;
else if (tp->snd_cwnd > tp->snd_cwnd_clamp)
--
1.8.3.1