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Commit 31954cd8 authored by Wei Wang's avatar Wei Wang Committed by David S. Miller
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tcp: Refactor pingpong code 



Instead of using pingpong as a single bit information, we refactor the
code to treat it as a counter. When interactive session is detected,
we set pingpong count to TCP_PINGPONG_THRESH. And when pingpong count
is >= TCP_PINGPONG_THRESH, we consider the session in pingpong mode.

This patch is a pure refactor and sets foundation for the next patch.
This patch itself does not change any pingpong logic.

Signed-off-by: default avatarWei Wang <weiwan@google.com>
Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fb1b6999

include/net/inet_connection_sock.h

+17 −0
Original line number Diff line number Diff line
@@ -314,4 +314,21 @@ int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname, 
			       char __user *optval, unsigned int optlen);



struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);



#define TCP_PINGPONG_THRESH	1



static inline void inet_csk_enter_pingpong_mode(struct sock *sk)

{

	inet_csk(sk)->icsk_ack.pingpong = TCP_PINGPONG_THRESH;

}



static inline void inet_csk_exit_pingpong_mode(struct sock *sk)

{

	inet_csk(sk)->icsk_ack.pingpong = 0;

}



static inline bool inet_csk_in_pingpong_mode(struct sock *sk)

{

	return inet_csk(sk)->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;

}

#endif /* _INET_CONNECTION_SOCK_H */

net/dccp/input.c

+1 −1
Original line number Diff line number Diff line
@@ -480,7 +480,7 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk, 
			sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT);

		}



		if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||

		if (sk->sk_write_pending || inet_csk_in_pingpong_mode(sk) ||

		    icsk->icsk_accept_queue.rskq_defer_accept) {

			/* Save one ACK. Data will be ready after

			 * several ticks, if write_pending is set.

net/dccp/timer.c

+2 −2
Original line number Diff line number Diff line
@@ -199,7 +199,7 @@ static void dccp_delack_timer(struct timer_list *t) 
	icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;



	if (inet_csk_ack_scheduled(sk)) {

		if (!icsk->icsk_ack.pingpong) {

		if (!inet_csk_in_pingpong_mode(sk)) {

			/* Delayed ACK missed: inflate ATO. */

			icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1,

						 icsk->icsk_rto);
@@ -207,7 +207,7 @@ static void dccp_delack_timer(struct timer_list *t) 
			/* Delayed ACK missed: leave pingpong mode and

			 * deflate ATO.

			 */

			icsk->icsk_ack.pingpong = 0;

			inet_csk_exit_pingpong_mode(sk);

			icsk->icsk_ack.ato = TCP_ATO_MIN;

		}

		dccp_send_ack(sk);

net/ipv4/tcp.c

+5 −5
Original line number Diff line number Diff line
@@ -1551,7 +1551,7 @@ static void tcp_cleanup_rbuf(struct sock *sk, int copied) 
		    (copied > 0 &&

		     ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||

		      ((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&

		       !icsk->icsk_ack.pingpong)) &&

		       !inet_csk_in_pingpong_mode(sk))) &&

		      !atomic_read(&sk->sk_rmem_alloc)))

			time_to_ack = true;

	}
@@ -2984,16 +2984,16 @@ static int do_tcp_setsockopt(struct sock *sk, int level, 


	case TCP_QUICKACK:

		if (!val) {

			icsk->icsk_ack.pingpong = 1;

			inet_csk_enter_pingpong_mode(sk);

		} else {

			icsk->icsk_ack.pingpong = 0;

			inet_csk_exit_pingpong_mode(sk);

			if ((1 << sk->sk_state) &

			    (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&

			    inet_csk_ack_scheduled(sk)) {

				icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;

				tcp_cleanup_rbuf(sk, 1);

				if (!(val & 1))

					icsk->icsk_ack.pingpong = 1;

					inet_csk_enter_pingpong_mode(sk);

			}

		}

		break;
@@ -3407,7 +3407,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level, 
		return 0;

	}

	case TCP_QUICKACK:

		val = !icsk->icsk_ack.pingpong;

		val = !inet_csk_in_pingpong_mode(sk);

		break;



	case TCP_CONGESTION:

net/ipv4/tcp_input.c

+4 −4
Original line number Diff line number Diff line
@@ -221,7 +221,7 @@ void tcp_enter_quickack_mode(struct sock *sk, unsigned int max_quickacks) 
	struct inet_connection_sock *icsk = inet_csk(sk);



	tcp_incr_quickack(sk, max_quickacks);

	icsk->icsk_ack.pingpong = 0;

	inet_csk_exit_pingpong_mode(sk);

	icsk->icsk_ack.ato = TCP_ATO_MIN;

}

EXPORT_SYMBOL(tcp_enter_quickack_mode);
@@ -236,7 +236,7 @@ static bool tcp_in_quickack_mode(struct sock *sk) 
	const struct dst_entry *dst = __sk_dst_get(sk);



	return (dst && dst_metric(dst, RTAX_QUICKACK)) ||

		(icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong);

		(icsk->icsk_ack.quick && !inet_csk_in_pingpong_mode(sk));

}



static void tcp_ecn_queue_cwr(struct tcp_sock *tp)
@@ -4094,7 +4094,7 @@ void tcp_fin(struct sock *sk) 
	case TCP_ESTABLISHED:

		/* Move to CLOSE_WAIT */

		tcp_set_state(sk, TCP_CLOSE_WAIT);

		inet_csk(sk)->icsk_ack.pingpong = 1;

		inet_csk_enter_pingpong_mode(sk);

		break;



	case TCP_CLOSE_WAIT:
@@ -5889,7 +5889,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, 
			return -1;

		if (sk->sk_write_pending ||

		    icsk->icsk_accept_queue.rskq_defer_accept ||

		    icsk->icsk_ack.pingpong) {

		    inet_csk_in_pingpong_mode(sk)) {

			/* Save one ACK. Data will be ready after

			 * several ticks, if write_pending is set.

			 *