[NET]: Reorder fields of struct dst_entry
This last patch (but not least :) ) finally moves the next pointer at
the end of struct dst_entry. This permits to perform route cache
lookups with a minimal cost of one cache line per entry, instead of
two.
Both 32bits and 64bits platforms benefit from this new layout.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/dst.h b/include/net/dst.h
index 5d62342..e12a8ce 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -37,14 +37,7 @@
struct dst_entry
{
- union {
- struct dst_entry *next;
- struct rtable *rt_next;
- struct rt6_info *rt6_next;
- struct dn_route *dn_next;
- };
- atomic_t __refcnt; /* client references */
- int __use;
+ struct rcu_head rcu_head;
struct dst_entry *child;
struct net_device *dev;
short error;
@@ -55,7 +48,6 @@
#define DST_NOPOLICY 4
#define DST_NOHASH 8
#define DST_BALANCED 0x10
- unsigned long lastuse;
unsigned long expires;
unsigned short header_len; /* more space at head required */
@@ -80,8 +72,16 @@
#endif
struct dst_ops *ops;
- struct rcu_head rcu_head;
+ unsigned long lastuse;
+ atomic_t __refcnt; /* client references */
+ int __use;
+ union {
+ struct dst_entry *next;
+ struct rtable *rt_next;
+ struct rt6_info *rt6_next;
+ struct dn_route *dn_next;
+ };
char info[0];
};