4.7-stable review patch. If anyone has any objections, please let me know.
------------------
From: Artem Germanov <agermanov@xxxxxxxxxxxxxx>
[ Upstream commit db7196a0d0984b933ccf2cd6a60e26abf466e8a3 ]
Commit 76174004a0f19785a328f40388e87e982bbf69b9
(tcp: do not slow start when cwnd equals ssthresh )
introduced regression in TCP YeAH. Using 100ms delay 1% loss virtual
ethernet link kernel 4.2 shows bandwidth ~500KB/s for single TCP
connection and kernel 4.3 and above (including 4.8-rc4) shows bandwidth
~100KB/s.
That is caused by stalled cwnd when cwnd equals ssthresh. This patch
fixes it by proper increasing cwnd in this case.
Signed-off-by: Artem Germanov <agermanov@xxxxxxxxxxxxxx>
Acked-by: Dmitry Adamushko <d.adamushko@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_yeah.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv4/tcp_yeah.c
+++ b/net/ipv4/tcp_yeah.c
@@ -76,7 +76,7 @@ static void tcp_yeah_cong_avoid(struct s
if (!tcp_is_cwnd_limited(sk))
return;
- if (tp->snd_cwnd <= tp->snd_ssthresh)
+ if (tcp_in_slow_start(tp))
tcp_slow_start(tp, acked);
else if (!yeah->doing_reno_now) {
--
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