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 <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Nandita Dukkipati <nanditad@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 @@
*/
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 @@
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 @@
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);
}