datapath: Optimize updating for OvS flow_stats.

Upstream commit:
	commit c57c054eb5b1ccf230c49f736f7a018fcbc3e952
	Author: Tonghao Zhang <[email protected]>
	Date:   Mon Jul 17 23:28:05 2017 -0700

	openvswitch: Optimize updating for OvS flow_stats.

	In the ovs_flow_stats_update(), we only use the node
	var to alloc flow_stats struct. But this is not a
	common case, it is unnecessary to call the numa_node_id()
	everytime. This patch is not a bugfix, but there maybe
	a small increase.

	Signed-off-by: Tonghao Zhang <[email protected]>
	Signed-off-by: David S. Miller <[email protected]>

Signed-off-by: Tonghao Zhang <[email protected]>
Signed-off-by: Andy Zhou <[email protected]>

datapath/flow.c

@@ -71,7 +71,6 @@ void ovs_flow_stats_update(struct sw_flow *flow, __be16 tcp_flags,
 			   const struct sk_buff *skb)
 {
 	struct flow_stats *stats;
-	int node = numa_node_id();
 	int cpu = smp_processor_id();
 	int len = skb->len + (skb_vlan_tag_present(skb) ? VLAN_HLEN : 0);
 
@@ -107,7 +106,7 @@ void ovs_flow_stats_update(struct sw_flow *flow, __be16 tcp_flags,
                                                               __GFP_THISNODE |
                                                               __GFP_NOWARN |
 							      __GFP_NOMEMALLOC,
-							      node);
+							      numa_node_id());
 				if (likely(new_stats)) {
 					new_stats->used = jiffies;
 					new_stats->packet_count = 1;