mm, page_alloc: inline zone_statistics

zone_statistics has one call-site but it's a public function.  Make it
static and inline.

The performance difference on a page allocator microbenchmark is;

                                             4.6.0-rc2                  4.6.0-rc2
                                      statbranch-v1r20           statinline-v1r20
  Min      alloc-odr0-1               419.00 (  0.00%)           412.00 (  1.67%)
  Min      alloc-odr0-2               305.00 (  0.00%)           301.00 (  1.31%)
  Min      alloc-odr0-4               250.00 (  0.00%)           247.00 (  1.20%)
  Min      alloc-odr0-8               219.00 (  0.00%)           215.00 (  1.83%)
  Min      alloc-odr0-16              203.00 (  0.00%)           199.00 (  1.97%)
  Min      alloc-odr0-32              195.00 (  0.00%)           191.00 (  2.05%)
  Min      alloc-odr0-64              191.00 (  0.00%)           187.00 (  2.09%)
  Min      alloc-odr0-128             189.00 (  0.00%)           185.00 (  2.12%)
  Min      alloc-odr0-256             198.00 (  0.00%)           193.00 (  2.53%)
  Min      alloc-odr0-512             210.00 (  0.00%)           207.00 (  1.43%)
  Min      alloc-odr0-1024            216.00 (  0.00%)           213.00 (  1.39%)
  Min      alloc-odr0-2048            221.00 (  0.00%)           220.00 (  0.45%)
  Min      alloc-odr0-4096            227.00 (  0.00%)           226.00 (  0.44%)
  Min      alloc-odr0-8192            232.00 (  0.00%)           229.00 (  1.29%)
  Min      alloc-odr0-16384           232.00 (  0.00%)           229.00 (  1.29%)

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/vmstat.h

@@ -163,12 +163,10 @@ static inline unsigned long zone_page_state_snapshot(struct zone *zone,
 #ifdef CONFIG_NUMA
 
 extern unsigned long node_page_state(int node, enum zone_stat_item item);
-extern void zone_statistics(struct zone *, struct zone *, gfp_t gfp);
 
 #else
 
 #define node_page_state(node, item) global_page_state(item)
-#define zone_statistics(_zl, _z, gfp) do { } while (0)
 
 #endif /* CONFIG_NUMA */
 

mm/page_alloc.c

@@ -2354,6 +2354,37 @@ int split_free_page(struct page *page)
 	return nr_pages;
 }
 
+/*
+ * Update NUMA hit/miss statistics
+ *
+ * Must be called with interrupts disabled.
+ *
+ * When __GFP_OTHER_NODE is set assume the node of the preferred
+ * zone is the local node. This is useful for daemons who allocate
+ * memory on behalf of other processes.
+ */
+static inline void zone_statistics(struct zone *preferred_zone, struct zone *z,
+								gfp_t flags)
+{
+#ifdef CONFIG_NUMA
+	int local_nid = numa_node_id();
+	enum zone_stat_item local_stat = NUMA_LOCAL;
+
+	if (unlikely(flags & __GFP_OTHER_NODE)) {
+		local_stat = NUMA_OTHER;
+		local_nid = preferred_zone->node;
+	}
+
+	if (z->node == local_nid) {
+		__inc_zone_state(z, NUMA_HIT);
+		__inc_zone_state(z, local_stat);
+	} else {
+		__inc_zone_state(z, NUMA_MISS);
+		__inc_zone_state(preferred_zone, NUMA_FOREIGN);
+	}
+#endif
+}
+
 /*
  * Allocate a page from the given zone. Use pcplists for order-0 allocations.
  */

mm/vmstat.c

@@ -569,35 +569,6 @@ void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
 #endif
 
 #ifdef CONFIG_NUMA
-/*
- * zonelist = the list of zones passed to the allocator
- * z 	    = the zone from which the allocation occurred.
- *
- * Must be called with interrupts disabled.
- *
- * When __GFP_OTHER_NODE is set assume the node of the preferred
- * zone is the local node. This is useful for daemons who allocate
- * memory on behalf of other processes.
- */
-void zone_statistics(struct zone *preferred_zone, struct zone *z, gfp_t flags)
-{
-	int local_nid = numa_node_id();
-	enum zone_stat_item local_stat = NUMA_LOCAL;
-
-	if (unlikely(flags & __GFP_OTHER_NODE)) {
-		local_stat = NUMA_OTHER;
-		local_nid = preferred_zone->node;
-	}
-
-	if (z->node == local_nid) {
-		__inc_zone_state(z, NUMA_HIT);
-		__inc_zone_state(z, local_stat);
-	} else {
-		__inc_zone_state(z, NUMA_MISS);
-		__inc_zone_state(preferred_zone, NUMA_FOREIGN);
-	}
-}
-
 /*
  * Determine the per node value of a stat item.
  */