[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>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 3a5bbbe7dd85..e5beca7de86c 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -113,7 +113,7 @@
  *      Snmp MIB for the UDP layer
  */
 
-DEFINE_SNMP_STAT(struct udp_mib, udp_statistics);
+DEFINE_SNMP_STAT(struct udp_mib, udp_statistics) __read_mostly;
 
 struct hlist_head udp_hash[UDP_HTABLE_SIZE];
 DEFINE_RWLOCK(udp_hash_lock);