diff --git a/net/key/af_key.c b/net/key/af_key.c
index 86b2c22..478c8b3 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -35,7 +35,7 @@
 #define _X2KEY(x) ((x) == XFRM_INF ? 0 : (x))
 #define _KEY2X(x) ((x) == 0 ? XFRM_INF : (x))
 
-static int pfkey_net_id;
+static int pfkey_net_id __read_mostly;
 struct netns_pfkey {
 	/* List of all pfkey sockets. */
 	struct hlist_head table;