[PATCH] [NET] reduce sizeof(struct flow)

[Eric Dumazet <dada1@cosmosbay.com>]

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Hi David

Each route entry includes a 'struct flow'. This structure has a current size 
of 80 bytes. This patch makes a size reduction depending on 
CONFIG_IPV6/CONFIG_IPV6_MODULE/CONFIG_DECNET/CONFIG_IP_ROUTE_FWMARK

For a platform doing IPV4 only, the new size is 36 bytes (instead of 80)
As many routers are base on PIII (L1_CACHE_SIZE=32), this saves one cache line 
per rtable entry.

Thank you

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>



[-- Attachment #2: shrink_flow.patch --]
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--- linux-2.6.19-rc2/include/net/flow.h	2006-10-18 06:03:08.000000000 +0200
+++ linux-2.6.19-rc2-ed/include/net/flow.h	2006-10-18 06:56:37.000000000 +0200
@@ -18,17 +18,21 @@
 		struct {
 			__be32			daddr;
 			__be32			saddr;
+#if defined(CONFIG_IP_ROUTE_FWMARK)
 			__u32			fwmark;
+#endif
 			__u8			tos;
 			__u8			scope;
 		} ip4_u;
 		
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 		struct {
 			struct in6_addr		daddr;
 			struct in6_addr		saddr;
 			__u32			fwmark;
 			__u32			flowlabel;
 		} ip6_u;
+#endif
 
 		struct {
 			__le16			daddr;
@@ -65,6 +69,7 @@
 			__u8	code;
 		} icmpt;
 
+#if defined(CONFIG_DECNET)
 		struct {
 			__le16	sport;
 			__le16	dport;
@@ -72,6 +77,7 @@
 			__u8	objnamel; /* Not 16 bits since max val is 16 */
 			__u8	objname[16]; /* Not zero terminated */
 		} dnports;
+#endif
 
 		__be32		spi;
 
--- linux-2.6.19-rc2/include/net/xfrm.h	2006-10-18 06:21:19.000000000 +0200
+++ linux-2.6.19-rc2-ed/include/net/xfrm.h	2006-10-18 06:53:41.000000000 +0200
@@ -517,6 +517,7 @@
 		(fl->oif == sel->ifindex || !sel->ifindex);
 }
 
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 static inline int
 __xfrm6_selector_match(struct xfrm_selector *sel, struct flowi *fl)
 {
@@ -527,6 +528,7 @@
 		(fl->proto == sel->proto || !sel->proto) &&
 		(fl->oif == sel->ifindex || !sel->ifindex);
 }
+#endif
 
 static inline int
 xfrm_selector_match(struct xfrm_selector *sel, struct flowi *fl,
@@ -535,8 +537,10 @@
 	switch (family) {
 	case AF_INET:
 		return __xfrm4_selector_match(sel, fl);
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	case AF_INET6:
 		return __xfrm6_selector_match(sel, fl);
+#endif
 	}
 	return 0;
 }
@@ -577,7 +581,9 @@
 		struct xfrm_dst		*next;
 		struct dst_entry	dst;
 		struct rtable		rt;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 		struct rt6_info		rt6;
+#endif
 	} u;
 	struct dst_entry *route;
 	u32 genid;
@@ -650,12 +656,14 @@
 		 tmpl->saddr.a4 != x->props.saddr.a4);
 }
 
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 static inline int
 __xfrm6_state_addr_cmp(struct xfrm_tmpl *tmpl, struct xfrm_state *x)
 {
 	return	(!ipv6_addr_any((struct in6_addr*)&tmpl->saddr) &&
 		 ipv6_addr_cmp((struct in6_addr *)&tmpl->saddr, (struct in6_addr*)&x->props.saddr));
 }
+#endif
 
 static inline int
 xfrm_state_addr_cmp(struct xfrm_tmpl *tmpl, struct xfrm_state *x, unsigned short family)
@@ -663,8 +671,10 @@
 	switch (family) {
 	case AF_INET:
 		return __xfrm4_state_addr_cmp(tmpl, x);
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	case AF_INET6:
 		return __xfrm6_state_addr_cmp(tmpl, x);
+#endif
 	}
 	return !0;
 }
@@ -762,8 +772,10 @@
 	switch (family){
 	case AF_INET:
 		return (xfrm_address_t *)&fl->fl4_dst;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	case AF_INET6:
 		return (xfrm_address_t *)&fl->fl6_dst;
+#endif
 	}
 	return NULL;
 }
@@ -774,8 +786,10 @@
 	switch (family){
 	case AF_INET:
 		return (xfrm_address_t *)&fl->fl4_src;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	case AF_INET6:
 		return (xfrm_address_t *)&fl->fl6_src;
+#endif
 	}
 	return NULL;
 }
@@ -790,6 +804,7 @@
 	return 0;
 }
 
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 static __inline__ int
 __xfrm6_state_addr_check(struct xfrm_state *x,
 			 xfrm_address_t *daddr, xfrm_address_t *saddr)
@@ -801,6 +816,7 @@
 		return 1;
 	return 0;
 }
+#endif
 
 static __inline__ int
 xfrm_state_addr_check(struct xfrm_state *x,
@@ -810,8 +826,10 @@
 	switch (family) {
 	case AF_INET:
 		return __xfrm4_state_addr_check(x, daddr, saddr);
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	case AF_INET6:
 		return __xfrm6_state_addr_check(x, daddr, saddr);
+#endif
 	}
 	return 0;
 }
@@ -825,10 +843,12 @@
 		return __xfrm4_state_addr_check(x,
 						(xfrm_address_t *)&fl->fl4_dst,
 						(xfrm_address_t *)&fl->fl4_src);
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 	case AF_INET6:
 		return __xfrm6_state_addr_check(x,
 						(xfrm_address_t *)&fl->fl6_dst,
 						(xfrm_address_t *)&fl->fl6_src);
+#endif
 	}
 	return 0;
 }