net: keep name_hlist close to name

__dev_get_by_name() is slow because pm_qos_req has been inserted between
name[] and name_hlist, adding cache misses.

pm_qos_req has nothing to do at the beginning of struct net_device
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -1046,10 +1046,9 @@ struct net_device {
 	 */
 	char			name[IFNAMSIZ];
 
-	struct pm_qos_request	pm_qos_req;
-
-	/* device name hash chain */
+	/* device name hash chain, please keep it close to name[] */
 	struct hlist_node	name_hlist;
+
 	/* snmp alias */
 	char 			*ifalias;
 
@@ -1322,6 +1321,8 @@ struct net_device {
 
 	/* group the device belongs to */
 	int group;
+
+	struct pm_qos_request	pm_qos_req;
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)