diff mbox series

[net-next,2/2] net-tcp_bbr: set tp->snd_ssthresh to BDP upon STARTUP exit

Message ID 20180316175149.224421-1-ysseung@google.com
State Accepted, archived
Delegated to: David Miller
Headers show
Series [net-next,1/2] tcp: add snd_ssthresh stat in SCM_TIMESTAMPING_OPT_STATS | expand

Commit Message

Yousuk Seung March 16, 2018, 5:51 p.m. UTC 
Set tp->snd_ssthresh to BDP upon STARTUP exit. This allows us
to check if a BBR flow exited STARTUP and the BDP at the
time of STARTUP exit with SCM_TIMESTAMPING_OPT_STATS. Since BBR does not
use snd_ssthresh this fix has no impact on BBR's behavior.

Signed-off-by: Yousuk Seung <ysseung@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
---
 net/ipv4/tcp_bbr.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

David Miller March 16, 2018, 7:08 p.m. UTC | #1 
From: Yousuk Seung <ysseung@google.com>
Date: Fri, 16 Mar 2018 10:51:49 -0700

> Set tp->snd_ssthresh to BDP upon STARTUP exit. This allows us
> to check if a BBR flow exited STARTUP and the BDP at the
> time of STARTUP exit with SCM_TIMESTAMPING_OPT_STATS. Since BBR does not
> use snd_ssthresh this fix has no impact on BBR's behavior.
> 
> Signed-off-by: Yousuk Seung <ysseung@google.com>
> Signed-off-by: Neal Cardwell <ncardwell@google.com>
> Signed-off-by: Priyaranjan Jha <priyarjha@google.com>
> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
> Signed-off-by: Yuchung Cheng <ycheng@google.com>

Applied.

Please submit future patch series with a proper cover letter.
Eric Dumazet March 16, 2018, 8:02 p.m. UTC | #2 
On 03/16/2018 10:51 AM, Yousuk Seung wrote:
> Set tp->snd_ssthresh to BDP upon STARTUP exit. This allows us
> to check if a BBR flow exited STARTUP and the BDP at the
> time of STARTUP exit with SCM_TIMESTAMPING_OPT_STATS. Since BBR does not
> use snd_ssthresh this fix has no impact on BBR's behavior.


Reviewed-by: Eric Dumazet <edumazet@google.com>
diff mbox series

Patch

diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c
index c92014cb1e16..158d105e76da 100644
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -731,6 +731,8 @@  static void bbr_check_drain(struct sock *sk, const struct rate_sample *rs)
 		bbr->mode = BBR_DRAIN;	/* drain queue we created */
 		bbr->pacing_gain = bbr_drain_gain;	/* pace slow to drain */
 		bbr->cwnd_gain = bbr_high_gain;	/* maintain cwnd */
+		tcp_sk(sk)->snd_ssthresh =
+				bbr_target_cwnd(sk, bbr_max_bw(sk), BBR_UNIT);
 	}	/* fall through to check if in-flight is already small: */
 	if (bbr->mode == BBR_DRAIN &&
 	    tcp_packets_in_flight(tcp_sk(sk)) <=
@@ -834,6 +836,7 @@  static void bbr_init(struct sock *sk)
 	struct bbr *bbr = inet_csk_ca(sk);
 
 	bbr->prior_cwnd = 0;
+	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
 	bbr->rtt_cnt = 0;
 	bbr->next_rtt_delivered = 0;
 	bbr->prev_ca_state = TCP_CA_Open;
@@ -886,7 +889,7 @@  static u32 bbr_undo_cwnd(struct sock *sk)
 static u32 bbr_ssthresh(struct sock *sk)
 {
 	bbr_save_cwnd(sk);
-	return TCP_INFINITE_SSTHRESH;	 /* BBR does not use ssthresh */
+	return tcp_sk(sk)->snd_ssthresh;
 }
 
 static size_t bbr_get_info(struct sock *sk, u32 ext, int *attr,