ipv6 fib: Make rt6_info{} more cache-line aware.
The head element of rt6_info{} is dst_entry{}, and
IPv6 specific elements follow.
Because elements at the end of dst_entry{} are frequently
updated, it is not good to put frequently-used static
elements, such as rt6i_idev, rt6i_dst or rt6i_flags in the
same cache line.
On the other hand, fib6_table, rt6i_node or rt6i_gateway are
rarely used, so it is okay to stay in the same cache line.
Let's rearrange rt6_info{}.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 86f46c4..4b1dc11 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -88,34 +88,37 @@
struct dst_entry dst;
} u;
- struct inet6_dev *rt6i_idev;
-
#define rt6i_dev u.dst.dev
#define rt6i_nexthop u.dst.neighbour
#define rt6i_expires u.dst.expires
+ /*
+ * Tail elements of dst_entry (__refcnt etc.)
+ * and these elements (rarely used in hot path) are in
+ * the same cache line.
+ */
+ struct fib6_table *rt6i_table;
struct fib6_node *rt6i_node;
struct in6_addr rt6i_gateway;
-
- u32 rt6i_flags;
- u32 rt6i_metric;
+
atomic_t rt6i_ref;
- /* more non-fragment space at head required */
- unsigned short rt6i_nfheader_len;
+ /* These are in a separate cache line. */
+ struct rt6key rt6i_dst ____cacheline_aligned_in_smp;
+ u32 rt6i_flags;
+ struct rt6key rt6i_src;
+ u32 rt6i_metric;
- u8 rt6i_protocol;
-
- struct fib6_table *rt6i_table;
-
- struct rt6key rt6i_dst;
+ struct inet6_dev *rt6i_idev;
#ifdef CONFIG_XFRM
u32 rt6i_flow_cache_genid;
#endif
+ /* more non-fragment space at head required */
+ unsigned short rt6i_nfheader_len;
- struct rt6key rt6i_src;
+ u8 rt6i_protocol;
};
static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)