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Commit ef9da47c authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by David S. Miller
Browse files

tcp: don't clear retransmit_skb_hint when not necessary 



Most importantly avoid doing it with cumulative ACK. Not clearing
means that we no longer need n^2 processing in resolution of each
fast recovery.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f0ceb0ed

include/net/tcp.h

+6 −1
Original line number Diff line number Diff line
@@ -1037,10 +1037,15 @@ static inline void tcp_mib_init(struct net *net) 
}



/* from STCP */

static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)

static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp)

{

	tp->lost_skb_hint = NULL;

	tp->scoreboard_skb_hint = NULL;

}



static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp)

{

	tcp_clear_retrans_hints_partial(tp);

	tp->retransmit_skb_hint = NULL;

}

net/ipv4/tcp_input.c

+3 −1
Original line number Diff line number Diff line
@@ -2925,7 +2925,9 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets) 


		tcp_unlink_write_queue(skb, sk);

		sk_wmem_free_skb(sk, skb);

		tcp_clear_all_retrans_hints(tp);

		tcp_clear_retrans_hints_partial(tp);

		if (skb == tp->retransmit_skb_hint)

			tp->retransmit_skb_hint = NULL;

	}



	if (skb && (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED))

net/ipv4/tcp_output.c

+5 −3
Original line number Diff line number Diff line
@@ -750,7 +750,7 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len, 


	BUG_ON(len > skb->len);



	tcp_clear_all_retrans_hints(tp);

	tcp_clear_retrans_hints_partial(tp);

	nsize = skb_headlen(skb) - len;

	if (nsize < 0)

		nsize = 0;
@@ -1823,7 +1823,9 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *skb, 
	tp->packets_out -= tcp_skb_pcount(next_skb);



	/* changed transmit queue under us so clear hints */

	tcp_clear_all_retrans_hints(tp);

	tcp_clear_retrans_hints_partial(tp);

	if (next_skb == tp->retransmit_skb_hint)

		tp->retransmit_skb_hint = skb;



	sk_wmem_free_skb(sk, next_skb);

}
@@ -1853,7 +1855,7 @@ void tcp_simple_retransmit(struct sock *sk) 
		}

	}



	tcp_clear_all_retrans_hints(tp);

	tcp_clear_retrans_hints_partial(tp);



	if (prior_lost == tp->lost_out)

		return;