This is a note to let you know that I've just added the patch titled
tcp_bbr: introduce bbr_bw_to_pacing_rate() helper
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tcp_bbr-introduce-bbr_bw_to_pacing_rate-helper.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Aug 8 16:27:53 PDT 2017
From: Neal Cardwell <ncardwell@xxxxxxxxxx>
Date: Fri, 14 Jul 2017 17:49:22 -0400
Subject: tcp_bbr: introduce bbr_bw_to_pacing_rate() helper
From: Neal Cardwell <ncardwell@xxxxxxxxxx>
[ Upstream commit f19fd62dafaf1ed6cf615dba655b82fa9df59074 ]
Introduce a helper to convert a BBR bandwidth and gain factor to a
pacing rate in bytes per second. This is a pure refactor, but is
needed for two following fixes.
Fixes: 0f8782ea1497 ("tcp_bbr: add BBR congestion control")
Signed-off-by: Neal Cardwell <ncardwell@xxxxxxxxxx>
Signed-off-by: Yuchung Cheng <ycheng@xxxxxxxxxx>
Signed-off-by: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_bbr.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -182,6 +182,16 @@ static u64 bbr_rate_bytes_per_sec(struct
return rate >> BW_SCALE;
}
+/* Convert a BBR bw and gain factor to a pacing rate in bytes per second. */
+static u32 bbr_bw_to_pacing_rate(struct sock *sk, u32 bw, int gain)
+{
+ u64 rate = bw;
+
+ rate = bbr_rate_bytes_per_sec(sk, rate, gain);
+ rate = min_t(u64, rate, sk->sk_max_pacing_rate);
+ return rate;
+}
+
/* Pace using current bw estimate and a gain factor. In order to help drive the
* network toward lower queues while maintaining high utilization and low
* latency, the average pacing rate aims to be slightly (~1%) lower than the
@@ -191,10 +201,8 @@ static u64 bbr_rate_bytes_per_sec(struct
*/
static void bbr_set_pacing_rate(struct sock *sk, u32 bw, int gain)
{
- u64 rate = bw;
+ u32 rate = bbr_bw_to_pacing_rate(sk, bw, gain);
- rate = bbr_rate_bytes_per_sec(sk, rate, gain);
- rate = min_t(u64, rate, sk->sk_max_pacing_rate);
if (bbr_full_bw_reached(sk) || rate > sk->sk_pacing_rate)
sk->sk_pacing_rate = rate;
}
Patches currently in stable-queue which might be from ncardwell@xxxxxxxxxx are
queue-4.9/tcp_bbr-remove-sk_pacing_rate-0-transient-during-init.patch
queue-4.9/tcp_bbr-introduce-bbr_bw_to_pacing_rate-helper.patch
queue-4.9/tcp_bbr-introduce-bbr_init_pacing_rate_from_rtt-helper.patch
queue-4.9/tcp_bbr-init-pacing-rate-on-first-rtt-sample.patch
queue-4.9/tcp_bbr-cut-pacing-rate-only-if-filled-pipe.patch