[PATCH net-next 0/9] inet: shrink netns_ipv{4|6}

[PATCH net-next 0/9] inet: shrink netns_ipv{4|6}

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

This patch series work on reducing footprint of netns_ipv4
and netns_ipv6. Some sysctls are converted to bytes,
and some fields are moves to reduce number of holes
and paddings.

Eric Dumazet (9):
  inet: shrink inet_timewait_death_row by 48 bytes
  inet: shrink netns_ipv4 by another cache line
  ipv4: convert fib_notify_on_flag_change sysctl to u8
  ipv4: convert udp_l3mdev_accept sysctl to u8
  ipv4: convert fib_multipath_{use_neigh|hash_policy} sysctls to u8
  ipv4: convert igmp_link_local_mcast_reports sysctl to u8
  tcp: convert tcp_comp_sack_nr sysctl to u8
  ipv6: convert elligible sysctls to u8
  ipv6: move ip6_dst_ops first in netns_ipv6

 include/net/netns/ipv4.h   | 25 ++++++++++++++-----------
 include/net/netns/ipv6.h   | 28 +++++++++++++++-------------
 net/ipv4/sysctl_net_ipv4.c | 26 ++++++++++++--------------
 net/ipv6/icmp.c            | 12 ++++++------
 net/ipv6/sysctl_net_ipv6.c | 38 ++++++++++++++++++--------------------
 5 files changed, 65 insertions(+), 64 deletions(-)

-- 
2.31.0.291.g576ba9dcdaf-goog

[PATCH net-next 1/9] inet: shrink inet_timewait_death_row by 48 bytes

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

struct inet_timewait_death_row uses two cache lines, because we want
tw_count to use a full cache line to avoid false sharing.

Rework its definition and placement in netns_ipv4 so that:

1) We add 60 bytes of padding after tw_count to avoid
  false sharing, knowing that tcp_death_row will
  have ____cacheline_aligned_in_smp attribute.

2) We do not risk padding before tcp_death_row, because
  we move it at the beginning of netns_ipv4, even if new
 fields are added later.

3) We do not waste 48 bytes of padding after it.

Note that I have not changed dccp.

pahole result for struct netns_ipv4 before/after the patch :

/* size: 832, cachelines: 13, members: 139 */
/* sum members: 721, holes: 12, sum holes: 95 */
/* padding: 16 */
/* paddings: 2, sum paddings: 55 */

->

/* size: 768, cachelines: 12, members: 139 */
/* sum members: 673, holes: 11, sum holes: 39 */
/* padding: 56 */
/* paddings: 2, sum paddings: 7 */
/* forced alignments: 1 */

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/netns/ipv4.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 9c8dd424d79b1d1100b6cbaa64d9fda9352a0b3a..1085ed4e0788d7cd432dfc7e5604ef3cd66dc337 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -32,14 +32,18 @@ struct inet_hashinfo;
 
 struct inet_timewait_death_row {
 	atomic_t		tw_count;
+	char			tw_pad[L1_CACHE_BYTES - sizeof(atomic_t)];
 
-	struct inet_hashinfo 	*hashinfo ____cacheline_aligned_in_smp;
+	struct inet_hashinfo 	*hashinfo;
 	int			sysctl_max_tw_buckets;
 };
 
 struct tcp_fastopen_context;
 
 struct netns_ipv4 {
+	/* Please keep tcp_death_row at first field in netns_ipv4 */
+	struct inet_timewait_death_row tcp_death_row ____cacheline_aligned_in_smp;
+
 #ifdef CONFIG_SYSCTL
 	struct ctl_table_header	*forw_hdr;
 	struct ctl_table_header	*frags_hdr;
@@ -175,7 +179,6 @@ struct netns_ipv4 {
 	int sysctl_tcp_comp_sack_nr;
 	unsigned long sysctl_tcp_comp_sack_delay_ns;
 	unsigned long sysctl_tcp_comp_sack_slack_ns;
-	struct inet_timewait_death_row tcp_death_row;
 	int sysctl_max_syn_backlog;
 	int sysctl_tcp_fastopen;
 	const struct tcp_congestion_ops __rcu  *tcp_congestion_control;
-- 
2.31.0.291.g576ba9dcdaf-goog

[PATCH net-next 2/9] inet: shrink netns_ipv4 by another cache line

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

By shuffling around some fields to remove 8 bytes of hole,
we can save one cache line.

pahole result before/after the patch :

/* size: 768, cachelines: 12, members: 139 */
/* sum members: 673, holes: 11, sum holes: 39 */
/* padding: 56 */
/* paddings: 2, sum paddings: 7 */
/* forced alignments: 1 */

->

/* size: 704, cachelines: 11, members: 139 */
/* sum members: 673, holes: 10, sum holes: 31 */
/* paddings: 2, sum paddings: 7 */
/* forced alignments: 1 */

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/netns/ipv4.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 1085ed4e0788d7cd432dfc7e5604ef3cd66dc337..538ed69919dc4d51acfd43c7d6d1fca611fcb003 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -57,17 +57,17 @@ struct netns_ipv4 {
 	struct mutex		ra_mutex;
 #ifdef CONFIG_IP_MULTIPLE_TABLES
 	struct fib_rules_ops	*rules_ops;
-	bool			fib_has_custom_rules;
-	unsigned int		fib_rules_require_fldissect;
 	struct fib_table __rcu	*fib_main;
 	struct fib_table __rcu	*fib_default;
+	unsigned int		fib_rules_require_fldissect;
+	bool			fib_has_custom_rules;
 #endif
 	bool			fib_has_custom_local_routes;
+	bool			fib_offload_disabled;
 #ifdef CONFIG_IP_ROUTE_CLASSID
 	int			fib_num_tclassid_users;
 #endif
 	struct hlist_head	*fib_table_hash;
-	bool			fib_offload_disabled;
 	struct sock		*fibnl;
 
 	struct sock  * __percpu	*icmp_sk;
-- 
2.31.0.291.g576ba9dcdaf-goog

[PATCH net-next 3/9] ipv4: convert fib_notify_on_flag_change sysctl to u8

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

Reduce footprint of sysctls.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/netns/ipv4.h   | 2 +-
 net/ipv4/sysctl_net_ipv4.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 538ed69919dc4d51acfd43c7d6d1fca611fcb003..b187ac597b8ce33376070bcd42c8c935b9c287eb 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -191,7 +191,7 @@ struct netns_ipv4 {
 	int sysctl_udp_wmem_min;
 	int sysctl_udp_rmem_min;
 
-	int sysctl_fib_notify_on_flag_change;
+	u8 sysctl_fib_notify_on_flag_change;
 
 #ifdef CONFIG_NET_L3_MASTER_DEV
 	int sysctl_udp_l3mdev_accept;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 9199f507a005efc3f57ca0225d3898bfa5d01c53..a2352d8d88cc9956ac0ddcaf351cbc996fa10add 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -1364,9 +1364,9 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "fib_notify_on_flag_change",
 		.data		= &init_net.ipv4.sysctl_fib_notify_on_flag_change,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_dou8vec_minmax,
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 	},
-- 
2.31.0.291.g576ba9dcdaf-goog

[PATCH net-next 4/9] ipv4: convert udp_l3mdev_accept sysctl to u8

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

Reduce footprint of sysctls.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/netns/ipv4.h   | 2 +-
 net/ipv4/sysctl_net_ipv4.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index b187ac597b8ce33376070bcd42c8c935b9c287eb..d309b1b897158c564ac8e07e4ed6826fa6e7c7b7 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -194,7 +194,7 @@ struct netns_ipv4 {
 	u8 sysctl_fib_notify_on_flag_change;
 
 #ifdef CONFIG_NET_L3_MASTER_DEV
-	int sysctl_udp_l3mdev_accept;
+	u8 sysctl_udp_l3mdev_accept;
 #endif
 
 	int sysctl_igmp_max_memberships;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index a2352d8d88cc9956ac0ddcaf351cbc996fa10add..1b6ce649a433c6614d9b1ac28d6c6c3daa01a525 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -1065,9 +1065,9 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "udp_l3mdev_accept",
 		.data		= &init_net.ipv4.sysctl_udp_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,
 	},
-- 
2.31.0.291.g576ba9dcdaf-goog

[PATCH net-next 5/9] ipv4: convert fib_multipath_{use_neigh|hash_policy} sysctls to u8

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

Make room for better packing of netns_ipv4

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/netns/ipv4.h   | 4 ++--
 net/ipv4/sysctl_net_ipv4.c | 8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index d309b1b897158c564ac8e07e4ed6826fa6e7c7b7..eb6ca07d3b0f5a3e0e90eee3e3049c0a0cc31d3d 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -220,8 +220,8 @@ struct netns_ipv4 {
 #endif
 #endif
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
-	int sysctl_fib_multipath_use_neigh;
-	int sysctl_fib_multipath_hash_policy;
+	u8 sysctl_fib_multipath_use_neigh;
+	u8 sysctl_fib_multipath_hash_policy;
 #endif
 
 	struct fib_notifier_ops	*notifier_ops;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 1b6ce649a433c6614d9b1ac28d6c6c3daa01a525..ad75d6bb2df7f60afda5c4a4f6524885a8b982c2 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -456,7 +456,7 @@ static int proc_fib_multipath_hash_policy(struct ctl_table *table, int write,
 	    ipv4.sysctl_fib_multipath_hash_policy);
 	int ret;
 
-	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+	ret = proc_dou8vec_minmax(table, write, buffer, lenp, ppos);
 	if (write && ret == 0)
 		call_netevent_notifiers(NETEVENT_IPV4_MPATH_HASH_UPDATE, net);
 
@@ -1038,16 +1038,16 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "fib_multipath_use_neigh",
 		.data		= &init_net.ipv4.sysctl_fib_multipath_use_neigh,
-		.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	= "fib_multipath_hash_policy",
 		.data		= &init_net.ipv4.sysctl_fib_multipath_hash_policy,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
 		.proc_handler	= proc_fib_multipath_hash_policy,
 		.extra1		= SYSCTL_ZERO,
-- 
2.31.0.291.g576ba9dcdaf-goog

[PATCH net-next 6/9] ipv4: convert igmp_link_local_mcast_reports sysctl to u8

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

This sysctl is a bool, can use less storage.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/netns/ipv4.h   | 2 +-
 net/ipv4/sysctl_net_ipv4.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index eb6ca07d3b0f5a3e0e90eee3e3049c0a0cc31d3d..fafcedf643832d80ebbd3d1c7c0fd8ac0866b99a 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -197,9 +197,9 @@ struct netns_ipv4 {
 	u8 sysctl_udp_l3mdev_accept;
 #endif
 
+	u8 sysctl_igmp_llm_reports;
 	int sysctl_igmp_max_memberships;
 	int sysctl_igmp_max_msf;
-	int sysctl_igmp_llm_reports;
 	int sysctl_igmp_qrv;
 
 	struct ping_group_range ping_group_range;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index ad75d6bb2df7f60afda5c4a4f6524885a8b982c2..fd2b35065bb21195f65b80d7a815221320f08eb3 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -848,9 +848,9 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "igmp_link_local_mcast_reports",
 		.data		= &init_net.ipv4.sysctl_igmp_llm_reports,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "igmp_max_memberships",
-- 
2.31.0.291.g576ba9dcdaf-goog

[PATCH net-next 7/9] tcp: convert tcp_comp_sack_nr sysctl to u8

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

tcp_comp_sack_nr max value was already 255.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/netns/ipv4.h   | 2 +-
 net/ipv4/sysctl_net_ipv4.c | 6 ++----
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index fafcedf643832d80ebbd3d1c7c0fd8ac0866b99a..87e1612497eae2fb2c893c6c64d14ad373862f43 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -171,12 +171,12 @@ struct netns_ipv4 {
 	u8 sysctl_tcp_min_tso_segs;
 	u8 sysctl_tcp_autocorking;
 	u8 sysctl_tcp_reflect_tos;
+	u8 sysctl_tcp_comp_sack_nr;
 	int sysctl_tcp_invalid_ratelimit;
 	int sysctl_tcp_pacing_ss_ratio;
 	int sysctl_tcp_pacing_ca_ratio;
 	int sysctl_tcp_wmem[3];
 	int sysctl_tcp_rmem[3];
-	int sysctl_tcp_comp_sack_nr;
 	unsigned long sysctl_tcp_comp_sack_delay_ns;
 	unsigned long sysctl_tcp_comp_sack_slack_ns;
 	int sysctl_max_syn_backlog;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index fd2b35065bb21195f65b80d7a815221320f08eb3..a09e466ce11d04201bb4014e6895243c3bb2abdb 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -46,7 +46,6 @@ static int tcp_syn_retries_min = 1;
 static int tcp_syn_retries_max = MAX_TCP_SYNCNT;
 static int ip_ping_group_range_min[] = { 0, 0 };
 static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX };
-static int comp_sack_nr_max = 255;
 static u32 u32_max_div_HZ = UINT_MAX / HZ;
 static int one_day_secs = 24 * 3600;
 
@@ -1330,11 +1329,10 @@ static struct ctl_table ipv4_net_table[] = {
 	{
 		.procname	= "tcp_comp_sack_nr",
 		.data		= &init_net.ipv4.sysctl_tcp_comp_sack_nr,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_dou8vec_minmax,
 		.extra1		= SYSCTL_ZERO,
-		.extra2		= &comp_sack_nr_max,
 	},
 	{
 		.procname       = "tcp_reflect_tos",
-- 
2.31.0.291.g576ba9dcdaf-goog

[PATCH net-next 8/9] ipv6: convert elligible sysctls to u8

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

Convert most sysctls that can fit in a byte.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/netns/ipv6.h   | 24 ++++++++++++------------
 net/ipv6/icmp.c            | 12 ++++++------
 net/ipv6/sysctl_net_ipv6.c | 38 ++++++++++++++++++--------------------
 3 files changed, 36 insertions(+), 38 deletions(-)

diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index 21c0debbd39ee34fb029746b0920961747dc41fa..84f4a8bec397dc5a15d84fae118cda33d87671bb 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -20,7 +20,6 @@ struct netns_sysctl_ipv6 {
 	struct ctl_table_header *frags_hdr;
 	struct ctl_table_header *xfrm6_hdr;
 #endif
-	int bindv6only;
 	int flush_delay;
 	int ip6_rt_max_size;
 	int ip6_rt_gc_min_interval;
@@ -29,21 +28,22 @@ struct netns_sysctl_ipv6 {
 	int ip6_rt_gc_elasticity;
 	int ip6_rt_mtu_expires;
 	int ip6_rt_min_advmss;
-	int multipath_hash_policy;
-	int flowlabel_consistency;
-	int auto_flowlabels;
+	u8 bindv6only;
+	u8 multipath_hash_policy;
+	u8 flowlabel_consistency;
+	u8 auto_flowlabels;
 	int icmpv6_time;
-	int icmpv6_echo_ignore_all;
-	int icmpv6_echo_ignore_multicast;
-	int icmpv6_echo_ignore_anycast;
+	u8 icmpv6_echo_ignore_all;
+	u8 icmpv6_echo_ignore_multicast;
+	u8 icmpv6_echo_ignore_anycast;
 	DECLARE_BITMAP(icmpv6_ratemask, ICMPV6_MSG_MAX + 1);
 	unsigned long *icmpv6_ratemask_ptr;
-	int anycast_src_echo_reply;
-	int ip_nonlocal_bind;
-	int fwmark_reflect;
+	u8 anycast_src_echo_reply;
+	u8 ip_nonlocal_bind;
+	u8 fwmark_reflect;
+	u8 flowlabel_state_ranges;
 	int idgen_retries;
 	int idgen_delay;
-	int flowlabel_state_ranges;
 	int flowlabel_reflect;
 	int max_dst_opts_cnt;
 	int max_hbh_opts_cnt;
@@ -51,7 +51,7 @@ struct netns_sysctl_ipv6 {
 	int max_hbh_opts_len;
 	int seg6_flowlabel;
 	bool skip_notify_on_dev_down;
-	int fib_notify_on_flag_change;
+	u8 fib_notify_on_flag_change;
 };
 
 struct netns_ipv6 {
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 29d38d6b55fb3c6587d3813c606c3813d789ad62..1bca2b09d77e64e4dd6177afe4765c53d3b18c05 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -1169,23 +1169,23 @@ static struct ctl_table ipv6_icmp_table_template[] = {
 	{
 		.procname	= "echo_ignore_all",
 		.data		= &init_net.ipv6.sysctl.icmpv6_echo_ignore_all,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler = proc_dointvec,
+		.proc_handler = proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "echo_ignore_multicast",
 		.data		= &init_net.ipv6.sysctl.icmpv6_echo_ignore_multicast,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler = proc_dointvec,
+		.proc_handler = proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "echo_ignore_anycast",
 		.data		= &init_net.ipv6.sysctl.icmpv6_echo_ignore_anycast,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler = proc_dointvec,
+		.proc_handler = proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "ratemask",
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 263ab43ed06bc964431235df8ff524ce74be5922..27102c3d6e1da00c194b43259d6db5b38234833a 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -23,7 +23,6 @@
 
 static int two = 2;
 static int flowlabel_reflect_max = 0x7;
-static int auto_flowlabels_min;
 static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX;
 
 static int proc_rt6_multipath_hash_policy(struct ctl_table *table, int write,
@@ -34,7 +33,7 @@ static int proc_rt6_multipath_hash_policy(struct ctl_table *table, int write,
 
 	net = container_of(table->data, struct net,
 			   ipv6.sysctl.multipath_hash_policy);
-	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+	ret = proc_dou8vec_minmax(table, write, buffer, lenp, ppos);
 	if (write && ret == 0)
 		call_netevent_notifiers(NETEVENT_IPV6_MPATH_HASH_UPDATE, net);
 
@@ -45,39 +44,38 @@ static struct ctl_table ipv6_table_template[] = {
 	{
 		.procname	= "bindv6only",
 		.data		= &init_net.ipv6.sysctl.bindv6only,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "anycast_src_echo_reply",
 		.data		= &init_net.ipv6.sysctl.anycast_src_echo_reply,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "flowlabel_consistency",
 		.data		= &init_net.ipv6.sysctl.flowlabel_consistency,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "auto_flowlabels",
 		.data		= &init_net.ipv6.sysctl.auto_flowlabels,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &auto_flowlabels_min,
+		.proc_handler	= proc_dou8vec_minmax,
 		.extra2		= &auto_flowlabels_max
 	},
 	{
 		.procname	= "fwmark_reflect",
 		.data		= &init_net.ipv6.sysctl.fwmark_reflect,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "idgen_retries",
@@ -96,16 +94,16 @@ static struct ctl_table ipv6_table_template[] = {
 	{
 		.procname	= "flowlabel_state_ranges",
 		.data		= &init_net.ipv6.sysctl.flowlabel_state_ranges,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "ip_nonlocal_bind",
 		.data		= &init_net.ipv6.sysctl.ip_nonlocal_bind,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dou8vec_minmax,
 	},
 	{
 		.procname	= "flowlabel_reflect",
@@ -147,7 +145,7 @@ static struct ctl_table ipv6_table_template[] = {
 	{
 		.procname	= "fib_multipath_hash_policy",
 		.data		= &init_net.ipv6.sysctl.multipath_hash_policy,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
 		.proc_handler   = proc_rt6_multipath_hash_policy,
 		.extra1		= SYSCTL_ZERO,
@@ -163,9 +161,9 @@ static struct ctl_table ipv6_table_template[] = {
 	{
 		.procname	= "fib_notify_on_flag_change",
 		.data		= &init_net.ipv6.sysctl.fib_notify_on_flag_change,
-		.maxlen		= sizeof(int),
+		.maxlen		= sizeof(u8),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_dou8vec_minmax,
 		.extra1         = SYSCTL_ZERO,
 		.extra2         = &two,
 	},
-- 
2.31.0.291.g576ba9dcdaf-goog

[PATCH net-next 9/9] ipv6: move ip6_dst_ops first in netns_ipv6

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

ip6_dst_ops have cache line alignement.

Moving it at beginning of netns_ipv6
removes a 48 byte hole, and shrinks netns_ipv6
from 12 to 11 cache lines.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/netns/ipv6.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index 84f4a8bec397dc5a15d84fae118cda33d87671bb..808f0f79ea9c9b9094dc94b71e295e26a9202ad1 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -55,6 +55,9 @@ struct netns_sysctl_ipv6 {
 };
 
 struct netns_ipv6 {
+	/* Keep ip6_dst_ops at the beginning of netns_sysctl_ipv6 */
+	struct dst_ops		ip6_dst_ops;
+
 	struct netns_sysctl_ipv6 sysctl;
 	struct ipv6_devconf	*devconf_all;
 	struct ipv6_devconf	*devconf_dflt;
@@ -76,7 +79,6 @@ struct netns_ipv6 {
 	struct hlist_head       *fib_table_hash;
 	struct fib6_table       *fib6_main_tbl;
 	struct list_head	fib6_walkers;
-	struct dst_ops		ip6_dst_ops;
 	rwlock_t		fib6_walker_lock;
 	spinlock_t		fib6_gc_lock;
 	unsigned int		 ip6_rt_gc_expire;
-- 
2.31.0.291.g576ba9dcdaf-goog

Re: [PATCH net-next 0/9] inet: shrink netns_ipv{4|6}

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (refs/heads/master):

On Wed, 31 Mar 2021 10:52:04 -0700 you wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> This patch series work on reducing footprint of netns_ipv4
> and netns_ipv6. Some sysctls are converted to bytes,
> and some fields are moves to reduce number of holes
> and paddings.
> 
> [...]

Here is the summary with links:
  - [net-next,1/9] inet: shrink inet_timewait_death_row by 48 bytes
    https://git.kernel.org/netdev/net-next/c/1caf8d39c58f
  - [net-next,2/9] inet: shrink netns_ipv4 by another cache line
    https://git.kernel.org/netdev/net-next/c/490f33c4e704
  - [net-next,3/9] ipv4: convert fib_notify_on_flag_change sysctl to u8
    https://git.kernel.org/netdev/net-next/c/b2908fac5b7b
  - [net-next,4/9] ipv4: convert udp_l3mdev_accept sysctl to u8
    https://git.kernel.org/netdev/net-next/c/cd04bd022258
  - [net-next,5/9] ipv4: convert fib_multipath_{use_neigh|hash_policy} sysctls to u8
    https://git.kernel.org/netdev/net-next/c/be205fe6ec4f
  - [net-next,6/9] ipv4: convert igmp_link_local_mcast_reports sysctl to u8
    https://git.kernel.org/netdev/net-next/c/7d4b37ebb934
  - [net-next,7/9] tcp: convert tcp_comp_sack_nr sysctl to u8
    https://git.kernel.org/netdev/net-next/c/1c3289c93174
  - [net-next,8/9] ipv6: convert elligible sysctls to u8
    https://git.kernel.org/netdev/net-next/c/a6175633a2af
  - [net-next,9/9] ipv6: move ip6_dst_ops first in netns_ipv6
    https://git.kernel.org/netdev/net-next/c/0dd39d952f75

You are awesome, thank you!
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