Commit 0d14c394 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'support-tcp_rto_min_us-and-tcp_delack_max_us-for-set-getsockopt' 

Jason Xing says:

====================
support TCP_RTO_MIN_US and TCP_DELACK_MAX_US for set/getsockopt

Add set/getsockopt supports for TCP_RTO_MIN_US and TCP_DELACK_MAX_US.
====================

Link: https://patch.msgid.link/20250317120314.41404-1-kerneljasonxing@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 98b2c048 9552f908

Documentation/networking/ip-sysctl.rst

+2 −2
Original line number Diff line number Diff line
@@ -1229,8 +1229,8 @@ tcp_pingpong_thresh - INTEGER 
tcp_rto_min_us - INTEGER

	Minimal TCP retransmission timeout (in microseconds). Note that the

	rto_min route option has the highest precedence for configuring this

	setting, followed by the TCP_BPF_RTO_MIN socket option, followed by

	this tcp_rto_min_us sysctl.

	setting, followed by the TCP_BPF_RTO_MIN and TCP_RTO_MIN_US socket

	options, followed by this tcp_rto_min_us sysctl.



	The recommended practice is to use a value less or equal to 200000

	microseconds.

include/net/tcp.h

+1 −1
Original line number Diff line number Diff line
@@ -844,7 +844,7 @@ u32 tcp_delack_max(const struct sock *sk); 
static inline u32 tcp_rto_min(const struct sock *sk)

{

	const struct dst_entry *dst = __sk_dst_get(sk);

	u32 rto_min = inet_csk(sk)->icsk_rto_min;

	u32 rto_min = READ_ONCE(inet_csk(sk)->icsk_rto_min);



	if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))

		rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN);

include/uapi/linux/tcp.h

+2 −0
Original line number Diff line number Diff line
@@ -140,6 +140,8 @@ enum { 


#define TCP_IS_MPTCP		43	/* Is MPTCP being used? */

#define TCP_RTO_MAX_MS		44	/* max rto time in ms */

#define TCP_RTO_MIN_US		45	/* min rto time in us */

#define TCP_DELACK_MAX_US	46	/* max delayed ack time in us */



#define TCP_REPAIR_ON		1

#define TCP_REPAIR_OFF		0

net/ipv4/tcp.c

+24 −2
Original line number Diff line number Diff line
@@ -3352,8 +3352,8 @@ int tcp_disconnect(struct sock *sk, int flags) 
	icsk->icsk_probes_out = 0;

	icsk->icsk_probes_tstamp = 0;

	icsk->icsk_rto = TCP_TIMEOUT_INIT;

	icsk->icsk_rto_min = TCP_RTO_MIN;

	icsk->icsk_delack_max = TCP_DELACK_MAX;

	WRITE_ONCE(icsk->icsk_rto_min, TCP_RTO_MIN);

	WRITE_ONCE(icsk->icsk_delack_max, TCP_DELACK_MAX);

	tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;

	tcp_snd_cwnd_set(tp, TCP_INIT_CWND);

	tp->snd_cwnd_cnt = 0;
@@ -3833,6 +3833,22 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname, 
			return -EINVAL;

		WRITE_ONCE(inet_csk(sk)->icsk_rto_max, msecs_to_jiffies(val));

		return 0;

	case TCP_RTO_MIN_US: {

		int rto_min = usecs_to_jiffies(val);



		if (rto_min > TCP_RTO_MIN || rto_min < TCP_TIMEOUT_MIN)

			return -EINVAL;

		WRITE_ONCE(inet_csk(sk)->icsk_rto_min, rto_min);

		return 0;

	}

	case TCP_DELACK_MAX_US: {

		int delack_max = usecs_to_jiffies(val);



		if (delack_max > TCP_DELACK_MAX || delack_max < TCP_TIMEOUT_MIN)

			return -EINVAL;

		WRITE_ONCE(inet_csk(sk)->icsk_delack_max, delack_max);

		return 0;

	}

	}



	sockopt_lock_sock(sk);
@@ -4672,6 +4688,12 @@ int do_tcp_getsockopt(struct sock *sk, int level, 
	case TCP_RTO_MAX_MS:

		val = jiffies_to_msecs(tcp_rto_max(sk));

		break;

	case TCP_RTO_MIN_US:

		val = jiffies_to_usecs(READ_ONCE(inet_csk(sk)->icsk_rto_min));

		break;

	case TCP_DELACK_MAX_US:

		val = jiffies_to_usecs(READ_ONCE(inet_csk(sk)->icsk_delack_max));

		break;

	default:

		return -ENOPROTOOPT;

	}

net/ipv4/tcp_output.c

+1 −1
Original line number Diff line number Diff line
@@ -4179,7 +4179,7 @@ u32 tcp_delack_max(const struct sock *sk) 
{

	u32 delack_from_rto_min = max(tcp_rto_min(sk), 2) - 1;



	return min(inet_csk(sk)->icsk_delack_max, delack_from_rto_min);

	return min(READ_ONCE(inet_csk(sk)->icsk_delack_max), delack_from_rto_min);

}



/* Send out a delayed ack, the caller does the policy checking