diff options
| -rw-r--r-- | include/linux/tcp.h | 2 | ||||
| -rw-r--r-- | include/net/tcp.h | 5 | ||||
| -rw-r--r-- | net/ipv4/tcp.c | 2 | ||||
| -rw-r--r-- | net/ipv4/tcp_output.c | 19 |
4 files changed, 19 insertions, 9 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h index a9fbe22732c3..4791fd801945 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -295,7 +295,7 @@ struct tcp_sock { u32 packets_out; /* Packets which are "in flight" */ u32 retrans_out; /* Retransmitted packets out */ u32 max_packets_out; /* max packets_out in last window */ - u32 max_packets_seq; /* right edge of max_packets_out flight */ + u32 cwnd_usage_seq; /* right edge of cwnd usage tracking flight */ u16 urg_data; /* Saved octet of OOB data and control flags */ u8 ecn_flags; /* ECN status bits. */ diff --git a/include/net/tcp.h b/include/net/tcp.h index d10962b9f0d0..95c1d51393ac 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1295,11 +1295,14 @@ static inline bool tcp_is_cwnd_limited(const struct sock *sk) { const struct tcp_sock *tp = tcp_sk(sk); + if (tp->is_cwnd_limited) + return true; + /* If in slow start, ensure cwnd grows to twice what was ACKed. */ if (tcp_in_slow_start(tp)) return tcp_snd_cwnd(tp) < 2 * tp->max_packets_out; - return tp->is_cwnd_limited; + return false; } /* BBR congestion control needs pacing. diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index e373dde1f46f..997a80ce1e13 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3137,6 +3137,8 @@ int tcp_disconnect(struct sock *sk, int flags) tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; tcp_snd_cwnd_set(tp, TCP_INIT_CWND); tp->snd_cwnd_cnt = 0; + tp->is_cwnd_limited = 0; + tp->max_packets_out = 0; tp->window_clamp = 0; tp->delivered = 0; tp->delivered_ce = 0; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 290019de766d..c69f4d966024 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1875,15 +1875,20 @@ static void tcp_cwnd_validate(struct sock *sk, bool is_cwnd_limited) const struct tcp_congestion_ops *ca_ops = inet_csk(sk)->icsk_ca_ops; struct tcp_sock *tp = tcp_sk(sk); - /* Track the maximum number of outstanding packets in each - * window, and remember whether we were cwnd-limited then. + /* Track the strongest available signal of the degree to which the cwnd + * is fully utilized. If cwnd-limited then remember that fact for the + * current window. If not cwnd-limited then track the maximum number of + * outstanding packets in the current window. (If cwnd-limited then we + * chose to not update tp->max_packets_out to avoid an extra else + * clause with no functional impact.) */ - if (!before(tp->snd_una, tp->max_packets_seq) || - tp->packets_out > tp->max_packets_out || - is_cwnd_limited) { - tp->max_packets_out = tp->packets_out; - tp->max_packets_seq = tp->snd_nxt; + if (!before(tp->snd_una, tp->cwnd_usage_seq) || + is_cwnd_limited || + (!tp->is_cwnd_limited && + tp->packets_out > tp->max_packets_out)) { tp->is_cwnd_limited = is_cwnd_limited; + tp->max_packets_out = tp->packets_out; + tp->cwnd_usage_seq = tp->snd_nxt; } if (tcp_is_cwnd_limited(sk)) { |