[NET]: use __read_mostly on kmem_cache_t , DEFINE_SNMP_STAT pointers

This patch puts mostly read only data in the right section
(read_mostly), to help sharing of these data between CPUS without
memory ping pongs.

On one of my production machine, tcp_statistics was sitting in a
heavily modified cache line, so *every* SNMP update had to force a
reload.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 2d9eb7f..f310403 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -34,10 +34,10 @@
 #define RPC_BUFFER_MAXSIZE	(2048)
 #define RPC_BUFFER_POOLSIZE	(8)
 #define RPC_TASK_POOLSIZE	(8)
-static kmem_cache_t	*rpc_task_slabp;
-static kmem_cache_t	*rpc_buffer_slabp;
-static mempool_t	*rpc_task_mempool;
-static mempool_t	*rpc_buffer_mempool;
+static kmem_cache_t	*rpc_task_slabp __read_mostly;
+static kmem_cache_t	*rpc_buffer_slabp __read_mostly;
+static mempool_t	*rpc_task_mempool __read_mostly;
+static mempool_t	*rpc_buffer_mempool __read_mostly;
 
 static void			__rpc_default_timer(struct rpc_task *task);
 static void			rpciod_killall(void);