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Commit d452e6ca authored by Yuchung Cheng's avatar Yuchung Cheng Committed by David S. Miller
Browse files

tcp: tcp_cong_control helper 



Refactor and consolidate cwnd and rate updates into a new function
tcp_cong_control().

Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarEric Dumazet <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2d14a4de

net/ipv4/tcp_input.c

+19 −12
Original line number Diff line number Diff line
@@ -3323,6 +3323,24 @@ static inline bool tcp_may_raise_cwnd(const struct sock *sk, const int flag) 
	return flag & FLAG_DATA_ACKED;

}



/* The "ultimate" congestion control function that aims to replace the rigid

 * cwnd increase and decrease control (tcp_cong_avoid,tcp_*cwnd_reduction).

 * It's called toward the end of processing an ACK with precise rate

 * information. All transmission or retransmission are delayed afterwards.

 */

static void tcp_cong_control(struct sock *sk, u32 ack, u32 acked_sacked,

			     int flag)

{

	if (tcp_in_cwnd_reduction(sk)) {

		/* Reduce cwnd if state mandates */

		tcp_cwnd_reduction(sk, acked_sacked, flag);

	} else if (tcp_may_raise_cwnd(sk, flag)) {

		/* Advance cwnd if state allows */

		tcp_cong_avoid(sk, ack, acked_sacked);

	}

	tcp_update_pacing_rate(sk);

}



/* Check that window update is acceptable.

 * The function assumes that snd_una<=ack<=snd_next.

 */
@@ -3553,7 +3571,6 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) 
	int prior_packets = tp->packets_out;

	u32 prior_delivered = tp->delivered;

	int acked = 0; /* Number of packets newly acked */

	u32 acked_sacked; /* Number of packets newly acked or sacked */

	int rexmit = REXMIT_NONE; /* Flag to (re)transmit to recover losses */



	sack_state.first_sackt.v64 = 0;
@@ -3653,16 +3670,6 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) 
	if (tp->tlp_high_seq)

		tcp_process_tlp_ack(sk, ack, flag);



	acked_sacked = tp->delivered - prior_delivered;

	/* Advance cwnd if state allows */

	if (tcp_in_cwnd_reduction(sk)) {

		/* Reduce cwnd if state mandates */

		tcp_cwnd_reduction(sk, acked_sacked, flag);

	} else if (tcp_may_raise_cwnd(sk, flag)) {

		/* Advance cwnd if state allows */

		tcp_cong_avoid(sk, ack, acked_sacked);

	}



	if ((flag & FLAG_FORWARD_PROGRESS) || !(flag & FLAG_NOT_DUP)) {

		struct dst_entry *dst = __sk_dst_get(sk);

		if (dst)
@@ -3671,7 +3678,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) 


	if (icsk->icsk_pending == ICSK_TIME_RETRANS)

		tcp_schedule_loss_probe(sk);

	tcp_update_pacing_rate(sk);

	tcp_cong_control(sk, ack, tp->delivered - prior_delivered, flag);

	tcp_xmit_recovery(sk, rexmit);

	return 1;