Commit ec789686 authored by Neal Cardwell's avatar Neal Cardwell Committed by Greg Kroah-Hartman

tcp_bbr: introduce bbr_bw_to_pacing_rate() helper


[ Upstream commit f19fd62d ]

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: 0f8782ea ("tcp_bbr: add BBR congestion control")
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 73520d38
...@@ -182,6 +182,16 @@ static u64 bbr_rate_bytes_per_sec(struct sock *sk, u64 rate, int gain) ...@@ -182,6 +182,16 @@ static u64 bbr_rate_bytes_per_sec(struct sock *sk, u64 rate, int gain)
return rate >> BW_SCALE; 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 /* 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 * network toward lower queues while maintaining high utilization and low
* latency, the average pacing rate aims to be slightly (~1%) lower than the * 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 sock *sk, u64 rate, int gain) ...@@ -191,10 +201,8 @@ static u64 bbr_rate_bytes_per_sec(struct sock *sk, u64 rate, int gain)
*/ */
static void bbr_set_pacing_rate(struct sock *sk, u32 bw, int gain) 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) if (bbr_full_bw_reached(sk) || rate > sk->sk_pacing_rate)
sk->sk_pacing_rate = rate; sk->sk_pacing_rate = rate;
} }
......
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