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: NTonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/openvswitch/flow.c

@@ -72,7 +72,6 @@ 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);
 
@@ -108,7 +107,7 @@ 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;