Commit ee733cd8 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'tcp-minor-adjustments-for-low-pacing-rates' 



Eric Dumazet says:

====================
tcp: minor adjustments for low pacing rates

After pacing horizon addition, we have to adjust how we arm rto
timer, otherwise we might freeze very low pacing rate flows.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents b94c280d 916e6d1a

include/net/tcp.h

+8 −13
Original line number Diff line number Diff line
@@ -1289,26 +1289,22 @@ static inline bool tcp_needs_internal_pacing(const struct sock *sk) 
	return smp_load_acquire(&sk->sk_pacing_status) == SK_PACING_NEEDED;

}



/* Return in jiffies the delay before one skb is sent.

 * If @skb is NULL, we look at EDT for next packet being sent on the socket.

/* Estimates in how many jiffies next packet for this flow can be sent.

 * Scheduling a retransmit timer too early would be silly.

 */

static inline unsigned long tcp_pacing_delay(const struct sock *sk,

					     const struct sk_buff *skb)

static inline unsigned long tcp_pacing_delay(const struct sock *sk)

{

	s64 pacing_delay = skb ? skb->tstamp : tcp_sk(sk)->tcp_wstamp_ns;



	pacing_delay -= tcp_sk(sk)->tcp_clock_cache;

	s64 delay = tcp_sk(sk)->tcp_wstamp_ns - tcp_sk(sk)->tcp_clock_cache;



	return pacing_delay > 0 ? nsecs_to_jiffies(pacing_delay) : 0;

	return delay > 0 ? nsecs_to_jiffies(delay) : 0;

}



static inline void tcp_reset_xmit_timer(struct sock *sk,

					const int what,

					unsigned long when,

					const unsigned long max_when,

					const struct sk_buff *skb)

					const unsigned long max_when)

{

	inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk, skb),

	inet_csk_reset_xmit_timer(sk, what, when + tcp_pacing_delay(sk),

				  max_when);

}
@@ -1336,8 +1332,7 @@ static inline void tcp_check_probe_timer(struct sock *sk) 
{

	if (!tcp_sk(sk)->packets_out && !inet_csk(sk)->icsk_pending)

		tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0,

				     tcp_probe0_base(sk), TCP_RTO_MAX,

				     NULL);

				     tcp_probe0_base(sk), TCP_RTO_MAX);

}



static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq)

net/ipv4/tcp_input.c

+2 −2
Original line number Diff line number Diff line
@@ -3014,7 +3014,7 @@ void tcp_rearm_rto(struct sock *sk) 
			rto = usecs_to_jiffies(max_t(int, delta_us, 1));

		}

		tcp_reset_xmit_timer(sk, ICSK_TIME_RETRANS, rto,

				     TCP_RTO_MAX, tcp_rtx_queue_head(sk));

				     TCP_RTO_MAX);

	}

}
@@ -3291,7 +3291,7 @@ static void tcp_ack_probe(struct sock *sk) 
		unsigned long when = tcp_probe0_when(sk, TCP_RTO_MAX);



		tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0,

				     when, TCP_RTO_MAX, NULL);

				     when, TCP_RTO_MAX);

	}

}

net/ipv4/tcp_output.c

+12 −10
Original line number Diff line number Diff line
@@ -2593,8 +2593,7 @@ bool tcp_schedule_loss_probe(struct sock *sk, bool advancing_rto) 
	if (rto_delta_us > 0)

		timeout = min_t(u32, timeout, usecs_to_jiffies(rto_delta_us));



	tcp_reset_xmit_timer(sk, ICSK_TIME_LOSS_PROBE, timeout,

			     TCP_RTO_MAX, NULL);

	tcp_reset_xmit_timer(sk, ICSK_TIME_LOSS_PROBE, timeout, TCP_RTO_MAX);

	return true;

}
@@ -3113,6 +3112,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 
	const struct inet_connection_sock *icsk = inet_csk(sk);

	struct sk_buff *skb, *rtx_head, *hole = NULL;

	struct tcp_sock *tp = tcp_sk(sk);

	bool rearm_timer = false;

	u32 max_segs;

	int mib_idx;
@@ -3135,7 +3135,7 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 


		segs = tp->snd_cwnd - tcp_packets_in_flight(tp);

		if (segs <= 0)

			return;

			break;

		sacked = TCP_SKB_CB(skb)->sacked;

		/* In case tcp_shift_skb_data() have aggregated large skbs,

		 * we need to make sure not sending too bigs TSO packets
@@ -3160,10 +3160,10 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 
			continue;



		if (tcp_small_queue_check(sk, skb, 1))

			return;

			break;



		if (tcp_retransmit_skb(sk, skb, segs))

			return;

			break;



		NET_ADD_STATS(sock_net(sk), mib_idx, tcp_skb_pcount(skb));
@@ -3172,11 +3172,13 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 


		if (skb == rtx_head &&

		    icsk->icsk_pending != ICSK_TIME_REO_TIMEOUT)

			rearm_timer = true;



	}

	if (rearm_timer)

		tcp_reset_xmit_timer(sk, ICSK_TIME_RETRANS,

				     inet_csk(sk)->icsk_rto,

					     TCP_RTO_MAX,

					     skb);

	}

				     TCP_RTO_MAX);

}



/* We allow to exceed memory limits for FIN packets to expedite
@@ -3907,7 +3909,7 @@ void tcp_send_probe0(struct sock *sk) 
		 */

		timeout = TCP_RESOURCE_PROBE_INTERVAL;

	}

	tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, timeout, TCP_RTO_MAX, NULL);

	tcp_reset_xmit_timer(sk, ICSK_TIME_PROBE0, timeout, TCP_RTO_MAX);

}



int tcp_rtx_synack(const struct sock *sk, struct request_sock *req)