diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 807776928cb8..72705eaf4b84 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -218,6 +218,7 @@ struct tcp_sock { reord:1; /* reordering detected */ } rack; u16 advmss; /* Advertised MSS */ + u8 compressed_ack; u32 chrono_start; /* Start time in jiffies of a TCP chrono */ u32 chrono_stat[3]; /* Time in jiffies for chrono_stat stats */ u8 chrono_type:2, /* current chronograph type */ @@ -297,6 +298,7 @@ struct tcp_sock { u32 sacked_out; /* SACK'd packets */ struct hrtimer pacing_timer; + struct hrtimer compressed_ack_timer; /* from STCP, retrans queue hinting */ struct sk_buff* lost_skb_hint; diff --git a/include/net/tcp.h b/include/net/tcp.h index 511bd0fde1dc..952d842a604a 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -561,6 +561,9 @@ static inline void tcp_clear_xmit_timers(struct sock *sk) if (hrtimer_try_to_cancel(&tcp_sk(sk)->pacing_timer) == 1) __sock_put(sk); + if (hrtimer_try_to_cancel(&tcp_sk(sk)->compressed_ack_timer) == 1) + __sock_put(sk); + inet_csk_clear_xmit_timers(sk); } diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 62b776f90037..0a2ea0bbf867 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2595,6 +2595,7 @@ int tcp_disconnect(struct sock *sk, int flags) dst_release(sk->sk_rx_dst); sk->sk_rx_dst = NULL; tcp_saved_syn_free(tp); + tp->compressed_ack = 0; /* Clean up fastopen related fields */ tcp_free_fastopen_req(tp); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index f5622b250665..cc2ac5346b92 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4249,6 +4249,8 @@ static void tcp_sack_new_ofo_skb(struct sock *sk, u32 seq, u32 end_seq) * If the sack array is full, forget about the last one. */ if (this_sack >= TCP_NUM_SACKS) { + if (tp->compressed_ack) + tcp_send_ack(sk); this_sack--; tp->rx_opt.num_sacks--; sp--; @@ -5081,6 +5083,7 @@ static inline void tcp_data_snd_check(struct sock *sk) static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible) { struct tcp_sock *tp = tcp_sk(sk); + unsigned long rtt, delay; /* More than one full frame received... */ if (((tp->rcv_nxt - tp->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss && @@ -5092,15 +5095,35 @@ static void __tcp_ack_snd_check(struct sock *sk, int ofo_possible) (tp->rcv_nxt - tp->copied_seq < sk->sk_rcvlowat || __tcp_select_window(sk) >= tp->rcv_wnd)) || /* We ACK each frame or... */ - tcp_in_quickack_mode(sk) || - /* We have out of order data. */ - (ofo_possible && !RB_EMPTY_ROOT(&tp->out_of_order_queue))) { - /* Then ack it now */ + tcp_in_quickack_mode(sk)) { +send_now: tcp_send_ack(sk); - } else { - /* Else, send delayed ack. */ - tcp_send_delayed_ack(sk); + return; } + + if (!ofo_possible || RB_EMPTY_ROOT(&tp->out_of_order_queue)) { + tcp_send_delayed_ack(sk); + return; + } + + if (!tcp_is_sack(tp) || tp->compressed_ack >= 44) + goto send_now; + tp->compressed_ack++; + + if (hrtimer_is_queued(&tp->compressed_ack_timer)) + return; + + /* compress ack timer : 5 % of rtt, but no more than 1 ms */ + + rtt = tp->rcv_rtt_est.rtt_us; + if (tp->srtt_us && tp->srtt_us < rtt) + rtt = tp->srtt_us; + + delay = min_t(unsigned long, NSEC_PER_MSEC, + rtt * (NSEC_PER_USEC >> 3)/20); + sock_hold(sk); + hrtimer_start(&tp->compressed_ack_timer, ns_to_ktime(delay), + HRTIMER_MODE_REL_PINNED_SOFT); } static inline void tcp_ack_snd_check(struct sock *sk) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 0d8f950a9006..7ee98aad82b7 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -162,6 +162,13 @@ static void tcp_event_data_sent(struct tcp_sock *tp, /* Account for an ACK we sent. */ static inline void tcp_event_ack_sent(struct sock *sk, unsigned int pkts) { + struct tcp_sock *tp = tcp_sk(sk); + + if (unlikely(tp->compressed_ack)) { + tp->compressed_ack = 0; + if (hrtimer_try_to_cancel(&tp->compressed_ack_timer) == 1) + __sock_put(sk); + } tcp_dec_quickack_mode(sk, pkts); inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK); } diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 92bdf64fffae..3b3611729928 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -708,6 +708,27 @@ out: sock_put(sk); } +static enum hrtimer_restart tcp_compressed_ack_kick(struct hrtimer *timer) +{ + struct tcp_sock *tp = container_of(timer, struct tcp_sock, compressed_ack_timer); + struct sock *sk = (struct sock *)tp; + + bh_lock_sock(sk); + if (!sock_owned_by_user(sk)) { + if (tp->compressed_ack) + tcp_send_ack(sk); + } else { + if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED, + &sk->sk_tsq_flags)) + sock_hold(sk); + } + bh_unlock_sock(sk); + + sock_put(sk); + + return HRTIMER_NORESTART; +} + void tcp_init_xmit_timers(struct sock *sk) { inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer, @@ -715,4 +736,8 @@ void tcp_init_xmit_timers(struct sock *sk) hrtimer_init(&tcp_sk(sk)->pacing_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_SOFT); tcp_sk(sk)->pacing_timer.function = tcp_pace_kick; + + hrtimer_init(&tcp_sk(sk)->compressed_ack_timer, CLOCK_MONOTONIC, + HRTIMER_MODE_REL_PINNED_SOFT); + tcp_sk(sk)->compressed_ack_timer.function = tcp_compressed_ack_kick; }