tcp: Namespace-ify sysctl_tcp_pacing_ss_ratio

Also remove an obsolete comment about TCP pacing.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/netns/ipv4.h

@@ -152,6 +152,7 @@ struct netns_ipv4 {
 	int sysctl_tcp_min_rtt_wlen;
 	int sysctl_tcp_autocorking;
 	int sysctl_tcp_invalid_ratelimit;
+	int sysctl_tcp_pacing_ss_ratio;
 	struct inet_timewait_death_row tcp_death_row;
 	int sysctl_max_syn_backlog;
 	int sysctl_tcp_fastopen;

include/net/tcp.h

@@ -250,7 +250,6 @@ extern int sysctl_tcp_rmem[3];
 
 #define TCP_RACK_LOSS_DETECTION  0x1 /* Use RACK to detect losses */
 
-extern int sysctl_tcp_pacing_ss_ratio;
 extern int sysctl_tcp_pacing_ca_ratio;
 
 extern atomic_long_t tcp_memory_allocated;

net/ipv4/sysctl_net_ipv4.c

@@ -492,15 +492,6 @@ static struct ctl_table ipv4_table[] = {
 		.mode		= 0644,
 		.proc_handler   = proc_allowed_congestion_control,
 	},
-	{
-		.procname	= "tcp_pacing_ss_ratio",
-		.data		= &sysctl_tcp_pacing_ss_ratio,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &thousand,
-	},
 	{
 		.procname	= "tcp_pacing_ca_ratio",
 		.data		= &sysctl_tcp_pacing_ca_ratio,
@@ -1145,6 +1136,15 @@ static struct ctl_table ipv4_net_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_ms_jiffies,
 	},
+	{
+		.procname	= "tcp_pacing_ss_ratio",
+		.data		= &init_net.ipv4.sysctl_tcp_pacing_ss_ratio,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &thousand,
+	},
 	{ }
 };
 

net/ipv4/tcp_input.c

@@ -767,13 +767,6 @@ static void tcp_rtt_estimator(struct sock *sk, long mrtt_us)
 	tp->srtt_us = max(1U, srtt);
 }
 
-/* Set the sk_pacing_rate to allow proper sizing of TSO packets.
- * Note: TCP stack does not yet implement pacing.
- * FQ packet scheduler can be used to implement cheap but effective
- * TCP pacing, to smooth the burst on large writes when packets
- * in flight is significantly lower than cwnd (or rwin)
- */
-int sysctl_tcp_pacing_ss_ratio __read_mostly = 200;
 int sysctl_tcp_pacing_ca_ratio __read_mostly = 120;
 
 static void tcp_update_pacing_rate(struct sock *sk)
@@ -793,7 +786,7 @@ static void tcp_update_pacing_rate(struct sock *sk)
 	 *	 end of slow start and should slow down.
 	 */
 	if (tp->snd_cwnd < tp->snd_ssthresh / 2)
-		rate *= sysctl_tcp_pacing_ss_ratio;
+		rate *= sock_net(sk)->ipv4.sysctl_tcp_pacing_ss_ratio;
 	else
 		rate *= sysctl_tcp_pacing_ca_ratio;
 

net/ipv4/tcp_ipv4.c

@@ -2507,6 +2507,7 @@ static int __net_init tcp_sk_init(struct net *net)
 	net->ipv4.sysctl_tcp_min_rtt_wlen = 300;
 	net->ipv4.sysctl_tcp_autocorking = 1;
 	net->ipv4.sysctl_tcp_invalid_ratelimit = HZ/2;
+	net->ipv4.sysctl_tcp_pacing_ss_ratio = 200;
 
 	net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
 	spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);