netdev - [PATCH 1/7] [TCP]: Add bytes_acked (ABC) clearing to FRTO too

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Date:	Thu, 11 Oct 2007 14:41:01 +0300
From:	"Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>
To:	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org, TAKANO Ryousei <takano@...-inc.co.jp>
Subject: [PATCH 1/7] [TCP]: Add bytes_acked (ABC) clearing to FRTO too

I was reading tcp_enter_loss while looking for Cedric's bug and
noticed bytes_acked adjustment is missing from FRTO side.

Since bytes_acked will only be used in tcp_cong_avoid, I think
it's safe to assume RTO would be spurious. During FRTO cwnd
will be not controlled by tcp_cong_avoid and if FRTO calls for
conventional recovery, cwnd is adjusted and the result of wrong
assumption is cleared from bytes_acked. If RTO was in fact
spurious, we did normal ABC already and can continue without
any additional adjustments.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...sinki.fi>
---
 net/ipv4/tcp_input.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 101054c..e40857e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1687,6 +1687,7 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag)
 	tp->snd_cwnd_cnt = 0;
 	tp->snd_cwnd_stamp = tcp_time_stamp;
 	tp->frto_counter = 0;
+	tp->bytes_acked = 0;
 
 	tp->reordering = min_t(unsigned int, tp->reordering,
 					     sysctl_tcp_reordering);
@@ -2824,6 +2825,7 @@ static void tcp_conservative_spur_to_response(struct tcp_sock *tp)
 {
 	tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh);
 	tp->snd_cwnd_cnt = 0;
+	tp->bytes_acked = 0;
 	TCP_ECN_queue_cwr(tp);
 	tcp_moderate_cwnd(tp);
 }
-- 
1.5.0.6

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