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 <ych...@google.com>
Signed-off-by: Neal Cardwell <ncardw...@google.com>
Signed-off-by: Eric Dumazet <eduma...@google.com>
Signed-off-by: Nandita Dukkipati <nandi...@google.com>
---
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 950cfec..dba22fc 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 c037644..fd1405d 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 84be008..654729a 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 06d3d66..28011fb 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 882c08a..db78424 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 58469ff..82f0d9e 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 f71002e..2ab9bbb 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 a51d63a..b3d64f6 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 333bcb2..bf5ea9e 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 a6cea1d..13951c4 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 112151e..0d094b9 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 {
--
2.4.3.573.g4eafbef
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
