From 071d5080e33d6f24139e4213c2d9f97a2c21b602 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Thu, 9 Jul 2015 13:16:29 -0700 Subject: [PATCH] tcp: add tcp_in_slow_start helper Add a helper to test the slow start condition in various congestion control modules and other places. This is to prepare a slight improvement in policy as to exactly when to slow start. Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Signed-off-by: Eric Dumazet Signed-off-by: Nandita Dukkipati Signed-off-by: David S. Miller --- include/net/tcp.h | 7 ++++++- net/ipv4/tcp_bic.c | 2 +- net/ipv4/tcp_cong.c | 2 +- net/ipv4/tcp_cubic.c | 4 ++-- net/ipv4/tcp_highspeed.c | 2 +- net/ipv4/tcp_htcp.c | 2 +- net/ipv4/tcp_illinois.c | 2 +- net/ipv4/tcp_metrics.c | 2 +- net/ipv4/tcp_scalable.c | 2 +- net/ipv4/tcp_vegas.c | 6 +++--- net/ipv4/tcp_veno.c | 2 +- 11 files changed, 19 insertions(+), 14 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 950cfecaad3c..dba22fc1b065 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -989,6 +989,11 @@ static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) #define TCP_INFINITE_SSTHRESH 0x7fffffff +static inline bool tcp_in_slow_start(const struct tcp_sock *tp) +{ + return tp->snd_cwnd <= tp->snd_ssthresh; +} + static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) { return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; @@ -1065,7 +1070,7 @@ static inline bool tcp_is_cwnd_limited(const struct sock *sk) const struct tcp_sock *tp = tcp_sk(sk); /* If in slow start, ensure cwnd grows to twice what was ACKed. */ - if (tp->snd_cwnd <= tp->snd_ssthresh) + if (tcp_in_slow_start(tp)) return tp->snd_cwnd < 2 * tp->max_packets_out; return tp->is_cwnd_limited; diff --git a/net/ipv4/tcp_bic.c b/net/ipv4/tcp_bic.c index c037644eafb7..fd1405d37c14 100644 --- a/net/ipv4/tcp_bic.c +++ b/net/ipv4/tcp_bic.c @@ -146,7 +146,7 @@ static void bictcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) 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 { bictcp_update(ca, tp->snd_cwnd); diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c index 84be008c945c..654729a8cb23 100644 --- a/net/ipv4/tcp_cong.c +++ b/net/ipv4/tcp_cong.c @@ -413,7 +413,7 @@ void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 acked) return; /* In "safe" area, increase. */ - if (tp->snd_cwnd <= tp->snd_ssthresh) { + if (tcp_in_slow_start(tp)) { acked = tcp_slow_start(tp, acked); if (!acked) return; diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c index 06d3d665a9fd..28011fb1f4a2 100644 --- a/net/ipv4/tcp_cubic.c +++ b/net/ipv4/tcp_cubic.c @@ -320,7 +320,7 @@ static void bictcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) if (!tcp_is_cwnd_limited(sk)) return; - if (tp->snd_cwnd <= tp->snd_ssthresh) { + if (tcp_in_slow_start(tp)) { if (hystart && after(ack, ca->end_seq)) bictcp_hystart_reset(sk); acked = tcp_slow_start(tp, acked); @@ -439,7 +439,7 @@ static void bictcp_acked(struct sock *sk, u32 cnt, s32 rtt_us) ca->delay_min = delay; /* hystart triggers when cwnd is larger than some threshold */ - if (hystart && tp->snd_cwnd <= tp->snd_ssthresh && + if (hystart && tcp_in_slow_start(tp) && tp->snd_cwnd >= hystart_low_window) hystart_update(sk, delay); } diff --git a/net/ipv4/tcp_highspeed.c b/net/ipv4/tcp_highspeed.c index 882c08aae2f5..db7842495a64 100644 --- a/net/ipv4/tcp_highspeed.c +++ b/net/ipv4/tcp_highspeed.c @@ -116,7 +116,7 @@ static void hstcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) 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 { /* Update AIMD parameters. diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c index 58469fff6c18..82f0d9ed60f5 100644 --- a/net/ipv4/tcp_htcp.c +++ b/net/ipv4/tcp_htcp.c @@ -236,7 +236,7 @@ static void htcp_cong_avoid(struct sock *sk, u32 ack, u32 acked) 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 { /* In dangerous area, increase slowly. diff --git a/net/ipv4/tcp_illinois.c b/net/ipv4/tcp_illinois.c index f71002e4db0b..2ab9bbb6faff 100644 --- a/net/ipv4/tcp_illinois.c +++ b/net/ipv4/tcp_illinois.c @@ -268,7 +268,7 @@ static void tcp_illinois_cong_avoid(struct sock *sk, u32 ack, u32 acked) return; /* In slow start */ - if (tp->snd_cwnd <= tp->snd_ssthresh) + if (tcp_in_slow_start(tp)) tcp_slow_start(tp, acked); else { diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index a51d63a43e33..b3d64f61d922 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -461,7 +461,7 @@ void tcp_update_metrics(struct sock *sk) tcp_metric_set(tm, TCP_METRIC_CWND, tp->snd_cwnd); } - } else if (tp->snd_cwnd > tp->snd_ssthresh && + } else if (!tcp_in_slow_start(tp) && icsk->icsk_ca_state == TCP_CA_Open) { /* Cong. avoidance phase, cwnd is reliable. */ if (!tcp_metric_locked(tm, TCP_METRIC_SSTHRESH)) diff --git a/net/ipv4/tcp_scalable.c b/net/ipv4/tcp_scalable.c index 333bcb2415ff..bf5ea9e9bbc1 100644 --- a/net/ipv4/tcp_scalable.c +++ b/net/ipv4/tcp_scalable.c @@ -22,7 +22,7 @@ static void tcp_scalable_cong_avoid(struct sock *sk, u32 ack, u32 acked) 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 tcp_cong_avoid_ai(tp, min(tp->snd_cwnd, TCP_SCALABLE_AI_CNT), diff --git a/net/ipv4/tcp_vegas.c b/net/ipv4/tcp_vegas.c index a6cea1d5e20d..13951c4087d4 100644 --- a/net/ipv4/tcp_vegas.c +++ b/net/ipv4/tcp_vegas.c @@ -225,7 +225,7 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked) */ diff = tp->snd_cwnd * (rtt-vegas->baseRTT) / vegas->baseRTT; - if (diff > gamma && tp->snd_cwnd <= tp->snd_ssthresh) { + if (diff > gamma && tcp_in_slow_start(tp)) { /* Going too fast. Time to slow down * and switch to congestion avoidance. */ @@ -240,7 +240,7 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked) tp->snd_cwnd = min(tp->snd_cwnd, (u32)target_cwnd+1); tp->snd_ssthresh = tcp_vegas_ssthresh(tp); - } else if (tp->snd_cwnd <= tp->snd_ssthresh) { + } else if (tcp_in_slow_start(tp)) { /* Slow start. */ tcp_slow_start(tp, acked); } else { @@ -281,7 +281,7 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked) vegas->minRTT = 0x7fffffff; } /* Use normal slow start */ - else if (tp->snd_cwnd <= tp->snd_ssthresh) + else if (tcp_in_slow_start(tp)) tcp_slow_start(tp, acked); } diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c index 112151eeee45..0d094b995cd9 100644 --- a/net/ipv4/tcp_veno.c +++ b/net/ipv4/tcp_veno.c @@ -150,7 +150,7 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked) veno->diff = (tp->snd_cwnd << V_PARAM_SHIFT) - target_cwnd; - if (tp->snd_cwnd <= tp->snd_ssthresh) { + if (tcp_in_slow_start(tp)) { /* Slow start. */ tcp_slow_start(tp, acked); } else {