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Commit 618d9f25 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
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tcp: back retransmit_high when it over-estimated 



If lost skb is sacked, we might have nothing to retransmit
as high as the retransmit_high is pointing to, so place
it lower to avoid unnecessary walking.

This is mainly for the case where high L'ed skbs gets sacked.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 90638a04

net/ipv4/tcp_output.c

+10 −2
Original line number Original line Diff line number Diff line
@@ -2035,16 +2035,22 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 
	struct tcp_sock *tp = tcp_sk(sk);

	struct tcp_sock *tp = tcp_sk(sk);

	struct sk_buff *skb;

	struct sk_buff *skb;

	struct sk_buff *hole = NULL;

	struct sk_buff *hole = NULL;

	u32 last_lost;

	int mib_idx;

	int mib_idx;

	int fwd_rexmitting = 0;

	int fwd_rexmitting = 0;





	if (!tp->lost_out)

	if (!tp->lost_out)

		tp->retransmit_high = tp->snd_una;

		tp->retransmit_high = tp->snd_una;





	if (tp->retransmit_skb_hint)

	if (tp->retransmit_skb_hint) {

		skb = tp->retransmit_skb_hint;

		skb = tp->retransmit_skb_hint;

	else

		last_lost = TCP_SKB_CB(skb)->end_seq;

		if (after(last_lost, tp->retransmit_high))

			last_lost = tp->retransmit_high;

	} else {

		skb = tcp_write_queue_head(sk);

		skb = tcp_write_queue_head(sk);

		last_lost = tp->snd_una;

	}





	/* First pass: retransmit lost packets. */

	/* First pass: retransmit lost packets. */

	tcp_for_write_queue_from(skb, sk) {

	tcp_for_write_queue_from(skb, sk) {
@@ -2073,6 +2079,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 
			mib_idx = LINUX_MIB_TCPFORWARDRETRANS;

			mib_idx = LINUX_MIB_TCPFORWARDRETRANS;





		} else if (!before(TCP_SKB_CB(skb)->seq, tp->retransmit_high)) {

		} else if (!before(TCP_SKB_CB(skb)->seq, tp->retransmit_high)) {

			tp->retransmit_high = last_lost;

			if (!tcp_can_forward_retransmit(sk))

			if (!tcp_can_forward_retransmit(sk))

				break;

				break;

			/* Backtrack if necessary to non-L'ed skb */

			/* Backtrack if necessary to non-L'ed skb */
@@ -2089,6 +2096,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 
			continue;

			continue;





		} else {

		} else {

			last_lost = TCP_SKB_CB(skb)->end_seq;

			if (icsk->icsk_ca_state != TCP_CA_Loss)

			if (icsk->icsk_ca_state != TCP_CA_Loss)

				mib_idx = LINUX_MIB_TCPFASTRETRANS;

				mib_idx = LINUX_MIB_TCPFASTRETRANS;

			else

			else