ipv4: shrink netns_ipv4 with sysctl conversions

These sysctls that can fit in one byte instead of one int
are converted to save space and thus reduce cache line misses.

 - icmp_echo_ignore_all, icmp_echo_ignore_broadcasts,
 - icmp_ignore_bogus_error_responses, icmp_errors_use_inbound_ifaddr
 - tcp_ecn, tcp_ecn_fallback
 - ip_default_ttl, ip_no_pmtu_disc, ip_fwd_use_pmtu
 - ip_nonlocal_bind, ip_autobind_reuse
 - ip_dynaddr, ip_early_demux, raw_l3mdev_accept
 - nexthop_compat_mode, fwmark_reflect
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/netns/ipv4.h

@@ -83,36 +83,36 @@ struct netns_ipv4 {
 	struct xt_table		*nat_table;
 #endif
 
-	int sysctl_icmp_echo_ignore_all;
-	int sysctl_icmp_echo_ignore_broadcasts;
-	int sysctl_icmp_ignore_bogus_error_responses;
+	u8 sysctl_icmp_echo_ignore_all;
+	u8 sysctl_icmp_echo_ignore_broadcasts;
+	u8 sysctl_icmp_ignore_bogus_error_responses;
+	u8 sysctl_icmp_errors_use_inbound_ifaddr;
 	int sysctl_icmp_ratelimit;
 	int sysctl_icmp_ratemask;
-	int sysctl_icmp_errors_use_inbound_ifaddr;
 
 	struct local_ports ip_local_ports;
 
-	int sysctl_tcp_ecn;
-	int sysctl_tcp_ecn_fallback;
+	u8 sysctl_tcp_ecn;
+	u8 sysctl_tcp_ecn_fallback;
 
-	int sysctl_ip_default_ttl;
-	int sysctl_ip_no_pmtu_disc;
-	int sysctl_ip_fwd_use_pmtu;
+	u8 sysctl_ip_default_ttl;
+	u8 sysctl_ip_no_pmtu_disc;
+	u8 sysctl_ip_fwd_use_pmtu;
 	int sysctl_ip_fwd_update_priority;
-	int sysctl_ip_nonlocal_bind;
-	int sysctl_ip_autobind_reuse;
+	u8 sysctl_ip_nonlocal_bind;
+	u8 sysctl_ip_autobind_reuse;
 	/* Shall we try to damage output packets if routing dev changes? */
-	int sysctl_ip_dynaddr;
-	int sysctl_ip_early_demux;
+	u8 sysctl_ip_dynaddr;
+	u8 sysctl_ip_early_demux;
 #ifdef CONFIG_NET_L3_MASTER_DEV
-	int sysctl_raw_l3mdev_accept;
+	u8 sysctl_raw_l3mdev_accept;
 #endif
 	int sysctl_tcp_early_demux;
 	int sysctl_udp_early_demux;
 
-	int sysctl_nexthop_compat_mode;
+	u8 sysctl_nexthop_compat_mode;
 
-	int sysctl_fwmark_reflect;
+	u8 sysctl_fwmark_reflect;
 	int sysctl_tcp_fwmark_accept;
 #ifdef CONFIG_NET_L3_MASTER_DEV
 	int sysctl_tcp_l3mdev_accept;

net/ipv4/sysctl_net_ipv4.c

@@ -595,30 +595,30 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "icmp_echo_ignore_all",
 		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_all,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "icmp_echo_ignore_broadcasts",
 		.data		= &init_net.ipv4.sysctl_icmp_echo_ignore_broadcasts,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "icmp_ignore_bogus_error_responses",
 		.data		= &init_net.ipv4.sysctl_icmp_ignore_bogus_error_responses,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "icmp_errors_use_inbound_ifaddr",
 		.data		= &init_net.ipv4.sysctl_icmp_errors_use_inbound_ifaddr,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "icmp_ratelimit",
@@ -645,9 +645,9 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "raw_l3mdev_accept",
 		.data		= &init_net.ipv4.sysctl_raw_l3mdev_accept,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_dou8vec_minmax,
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
@@ -655,30 +655,30 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "tcp_ecn",
 		.data		= &init_net.ipv4.sysctl_tcp_ecn,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "tcp_ecn_fallback",
 		.data		= &init_net.ipv4.sysctl_tcp_ecn_fallback,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "ip_dynaddr",
 		.data		= &init_net.ipv4.sysctl_ip_dynaddr,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "ip_early_demux",
 		.data		= &init_net.ipv4.sysctl_ip_early_demux,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname       = "udp_early_demux",
@@ -697,18 +697,18 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname       = "nexthop_compat_mode",
 		.data           = &init_net.ipv4.sysctl_nexthop_compat_mode,
-		.maxlen         = sizeof(int),
+		.maxlen         = sizeof(u8),
 		.mode           = 0644,
-		.proc_handler   = proc_dointvec_minmax,
+		.proc_handler   = proc_dou8vec_minmax,
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "ip_default_ttl",
 		.data		= &init_net.ipv4.sysctl_ip_default_ttl,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_dou8vec_minmax,
 		.extra1		= &ip_ttl_min,
 		.extra2		= &ip_ttl_max,
 	},
@@ -729,16 +729,16 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "ip_no_pmtu_disc",
 		.data		= &init_net.ipv4.sysctl_ip_no_pmtu_disc,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "ip_forward_use_pmtu",
 		.data		= &init_net.ipv4.sysctl_ip_fwd_use_pmtu,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "ip_forward_update_priority",
@@ -752,25 +752,25 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "ip_nonlocal_bind",
 		.data		= &init_net.ipv4.sysctl_ip_nonlocal_bind,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "ip_autobind_reuse",
 		.data		= &init_net.ipv4.sysctl_ip_autobind_reuse,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_dou8vec_minmax,
 		.extra1         = SYSCTL_ZERO,
 		.extra2         = SYSCTL_ONE,
 	},
 	{
 		.procname	= "fwmark_reflect",
 		.data		= &init_net.ipv4.sysctl_fwmark_reflect,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "tcp_fwmark_accept",