[PATCH 08/24] net, diet: Make TCP metrics optional

[Andi Kleen]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

This is all the code that saves connection information
between different sockets. Not really essential for
small systems.

Saves about 5.5k text

   text	   data	    bss	    dec	    hex	filename
 492952	  19571	  13480	 526003	  806b3	net/built-in.o-with-metrics
 487675	  19275	  13480	 520430	  7f0ee	net/built-in.o-without-metrics

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 include/net/tcp.h          | 25 +++++++++++++++++++++++++
 net/ipv4/Kconfig           |  6 ++++++
 net/ipv4/Makefile          |  3 ++-
 net/ipv4/sysctl_net_ipv4.c |  2 ++
 4 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 87d8774..d741d2f 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -419,14 +419,29 @@ int tcp_child_process(struct sock *parent, struct sock *child,
 		      struct sk_buff *skb);
 void tcp_enter_loss(struct sock *sk, int how);
 void tcp_clear_retrans(struct tcp_sock *tp);
+#ifdef CONFIG_TCP_METRICS
 void tcp_update_metrics(struct sock *sk);
 void tcp_init_metrics(struct sock *sk);
 void tcp_metrics_init(void);
+
 bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst,
 			bool paws_check);
 bool tcp_remember_stamp(struct sock *sk);
 bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw);
 void tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst);
+#else
+static inline void tcp_update_metrics(struct sock *sk) {}
+static inline void tcp_init_metrics(struct sock *sk) {}
+static inline void tcp_metrics_init(void) {}
+static inline bool tcp_peer_is_proven(struct request_sock *req,
+				      struct dst_entry *dst,
+				      bool paws_check) { return false; }
+static inline bool tcp_remember_stamp(struct sock *sk) { return false; }
+static inline bool
+tcp_tw_remember_stamp(struct inet_timewait_sock *tw) { return false; }
+static inline void
+tcp_fetch_timewait_stamp(struct sock *sk, struct dst_entry *dst) {}
+#endif
 void tcp_disable_fack(struct tcp_sock *tp);
 void tcp_close(struct sock *sk, long timeout);
 void tcp_init_sock(struct sock *sk);
@@ -1296,11 +1311,21 @@ int tcp_md5_hash_key(struct tcp_md5sig_pool *hp,
 		     const struct tcp_md5sig_key *key);
 
 /* From tcp_fastopen.c */
+#ifdef CONFIG_TCP_METRICS
 void tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
 			    struct tcp_fastopen_cookie *cookie, int *syn_loss,
 			    unsigned long *last_syn_loss);
 void tcp_fastopen_cache_set(struct sock *sk, u16 mss,
 			    struct tcp_fastopen_cookie *cookie, bool syn_lost);
+#else
+static inline void
+tcp_fastopen_cache_get(struct sock *sk, u16 *mss,
+		       struct tcp_fastopen_cookie *cookie, int *syn_loss,
+		       unsigned long *last_syn_loss) {}
+static inline void
+tcp_fastopen_cache_set(struct sock *sk, u16 mss,
+		       struct tcp_fastopen_cookie *cookie, bool syn_lost) {}
+#endif
 struct tcp_fastopen_request {
 	/* Fast Open cookie. Size 0 means a cookie request */
 	struct tcp_fastopen_cookie	cookie;
diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 6146b1b..db2dada 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -264,6 +264,12 @@ config IP_PIMSM_V2
 	  gated-5). This routing protocol is not used widely, so say N unless
 	  you want to play with it.
 
+config TCP_METRICS
+	bool "Report TCP metrics over netlink"
+	---help---
+           Enable support in TCP to save host information between different
+	   connections.
+
 config SYN_COOKIES
 	bool "IP: TCP syncookie support"
 	---help---
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index 756855c..8b17b83 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -7,7 +7,7 @@ obj-y     := route.o inetpeer.o protocol.o \
 	     ip_output.o ip_sockglue.o inet_hashtables.o \
 	     inet_timewait_sock.o inet_connection_sock.o \
 	     tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \
-	     tcp_minisocks.o tcp_cong.o tcp_metrics.o tcp_fastopen.o \
+	     tcp_minisocks.o tcp_cong.o tcp_fastopen.o \
 	     tcp_offload.o datagram.o raw.o udp.o udplite.o \
 	     udp_offload.o arp.o icmp.o devinet.o af_inet.o igmp.o \
 	     fib_frontend.o fib_semantics.o fib_trie.o \
@@ -17,6 +17,7 @@ obj-$(CONFIG_NET_IP_TUNNEL) += ip_tunnel.o
 obj-$(CONFIG_IP_PING) += ping.o
 obj-$(CONFIG_SYSCTL) += sysctl_net_ipv4.o
 obj-$(CONFIG_PROC_FS) += proc.o
+obj-$(CONFIG_TCP_METRICS) += tcp_metrics.o
 obj-$(CONFIG_IP_MULTIPLE_TABLES) += fib_rules.o
 obj-$(CONFIG_IP_MROUTE) += ipmr.o
 obj-$(CONFIG_NET_IPIP) += ipip.o
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 44eba05..2110d2e 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -573,6 +573,7 @@ static struct ctl_table ipv4_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec
 	},
+#ifdef CONFIG_TCP_METRICS
 	{
 		.procname	= "tcp_no_metrics_save",
 		.data		= &sysctl_tcp_nometrics_save,
@@ -580,6 +581,7 @@ static struct ctl_table ipv4_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
+#endif
 	{
 		.procname	= "tcp_moderate_rcvbuf",
 		.data		= &sysctl_tcp_moderate_rcvbuf,
-- 
1.9.0

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