diff options
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -rw-r--r-- | net/ipv4/tcp_input.c | 58 |
1 files changed, 37 insertions, 21 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 45f750e85714..cfa51cfd2d99 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -97,6 +97,7 @@ int sysctl_tcp_max_orphans __read_mostly = NR_FILE; #define FLAG_SACK_RENEGING 0x2000 /* snd_una advanced to a sacked seq */ #define FLAG_UPDATE_TS_RECENT 0x4000 /* tcp_replace_ts_recent() */ #define FLAG_NO_CHALLENGE_ACK 0x8000 /* do not call tcp_send_challenge_ack() */ +#define FLAG_ACK_MAYBE_DELAYED 0x10000 /* Likely a delayed ACK */ #define FLAG_ACKED (FLAG_DATA_ACKED|FLAG_SYN_ACKED) #define FLAG_NOT_DUP (FLAG_DATA|FLAG_WIN_UPDATE|FLAG_ACKED) @@ -578,8 +579,8 @@ static inline void tcp_rcv_rtt_measure_ts(struct sock *sk, void tcp_rcv_space_adjust(struct sock *sk) { struct tcp_sock *tp = tcp_sk(sk); + u32 copied; int time; - int copied; tcp_mstamp_refresh(tp); time = tcp_stamp_us_delta(tp->tcp_mstamp, tp->rcvq_space.time); @@ -602,38 +603,31 @@ void tcp_rcv_space_adjust(struct sock *sk) if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf && !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { - int rcvwin, rcvmem, rcvbuf; + int rcvmem, rcvbuf; + u64 rcvwin, grow; /* minimal window to cope with packet losses, assuming * steady state. Add some cushion because of small variations. */ - rcvwin = (copied << 1) + 16 * tp->advmss; + rcvwin = ((u64)copied << 1) + 16 * tp->advmss; - /* If rate increased by 25%, - * assume slow start, rcvwin = 3 * copied - * If rate increased by 50%, - * assume sender can use 2x growth, rcvwin = 4 * copied - */ - if (copied >= - tp->rcvq_space.space + (tp->rcvq_space.space >> 2)) { - if (copied >= - tp->rcvq_space.space + (tp->rcvq_space.space >> 1)) - rcvwin <<= 1; - else - rcvwin += (rcvwin >> 1); - } + /* Accommodate for sender rate increase (eg. slow start) */ + grow = rcvwin * (copied - tp->rcvq_space.space); + do_div(grow, tp->rcvq_space.space); + rcvwin += (grow << 1); rcvmem = SKB_TRUESIZE(tp->advmss + MAX_TCP_HEADER); while (tcp_win_from_space(sk, rcvmem) < tp->advmss) rcvmem += 128; - rcvbuf = min(rcvwin / tp->advmss * rcvmem, - sock_net(sk)->ipv4.sysctl_tcp_rmem[2]); + do_div(rcvwin, tp->advmss); + rcvbuf = min_t(u64, rcvwin * rcvmem, + sock_net(sk)->ipv4.sysctl_tcp_rmem[2]); if (rcvbuf > sk->sk_rcvbuf) { sk->sk_rcvbuf = rcvbuf; /* Make the window clamp follow along. */ - tp->window_clamp = rcvwin; + tp->window_clamp = tcp_win_from_space(sk, rcvbuf); } } tp->rcvq_space.space = copied; @@ -2864,11 +2858,18 @@ static void tcp_fastretrans_alert(struct sock *sk, const u32 prior_snd_una, *rexmit = REXMIT_LOST; } -static void tcp_update_rtt_min(struct sock *sk, u32 rtt_us) +static void tcp_update_rtt_min(struct sock *sk, u32 rtt_us, const int flag) { u32 wlen = sock_net(sk)->ipv4.sysctl_tcp_min_rtt_wlen * HZ; struct tcp_sock *tp = tcp_sk(sk); + if ((flag & FLAG_ACK_MAYBE_DELAYED) && rtt_us > tcp_min_rtt(tp)) { + /* If the remote keeps returning delayed ACKs, eventually + * the min filter would pick it up and overestimate the + * prop. delay when it expires. Skip suspected delayed ACKs. + */ + return; + } minmax_running_min(&tp->rtt_min, wlen, tcp_jiffies32, rtt_us ? : jiffies_to_usecs(1)); } @@ -2908,7 +2909,7 @@ static bool tcp_ack_update_rtt(struct sock *sk, const int flag, * always taken together with ACK, SACK, or TS-opts. Any negative * values will be skipped with the seq_rtt_us < 0 check above. */ - tcp_update_rtt_min(sk, ca_rtt_us); + tcp_update_rtt_min(sk, ca_rtt_us, flag); tcp_rtt_estimator(sk, seq_rtt_us); tcp_set_rto(sk); @@ -3132,6 +3133,17 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack, if (likely(first_ackt) && !(flag & FLAG_RETRANS_DATA_ACKED)) { seq_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, first_ackt); ca_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, last_ackt); + + if (pkts_acked == 1 && last_in_flight < tp->mss_cache && + last_in_flight && !prior_sacked && fully_acked && + sack->rate->prior_delivered + 1 == tp->delivered && + !(flag & (FLAG_CA_ALERT | FLAG_SYN_ACKED))) { + /* Conservatively mark a delayed ACK. It's typically + * from a lone runt packet over the round trip to + * a receiver w/o out-of-order or CE events. + */ + flag |= FLAG_ACK_MAYBE_DELAYED; + } } if (sack->first_sackt) { sack_rtt_us = tcp_stamp_us_delta(tp->tcp_mstamp, sack->first_sackt); @@ -3621,6 +3633,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) delivered = tp->delivered - delivered; /* freshly ACKed or SACKed */ lost = tp->lost - lost; /* freshly marked lost */ + rs.is_ack_delayed = !!(flag & FLAG_ACK_MAYBE_DELAYED); tcp_rate_gen(sk, delivered, lost, is_sack_reneg, sack_state.rate); tcp_cong_control(sk, ack, delivered, flag, sack_state.rate); tcp_xmit_recovery(sk, rexmit); @@ -5306,6 +5319,9 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb, unsigned int len = skb->len; struct tcp_sock *tp = tcp_sk(sk); + /* TCP congestion window tracking */ + trace_tcp_probe(sk, skb); + tcp_mstamp_refresh(tp); if (unlikely(!sk->sk_rx_dst)) inet_csk(sk)->icsk_af_ops->sk_rx_dst_set(sk, skb); |