diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6e11cda1ba02..f0473a88ca2e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1053,6 +1053,7 @@ extern void set_dma_reserve(unsigned long new_dma_reserve);
 extern void memmap_init_zone(unsigned long, int, unsigned long,
 				unsigned long, enum memmap_context);
 extern void setup_per_zone_wmarks(void);
+extern void calculate_zone_inactive_ratio(struct zone *zone);
 extern void mem_init(void);
 extern void __init mmap_init(void);
 extern void show_mem(void);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8629c84fd9ba..303607f1d323 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4478,22 +4478,26 @@ void setup_per_zone_wmarks(void)
  *    1TB     101        10GB
  *   10TB     320        32GB
  */
+void calculate_zone_inactive_ratio(struct zone *zone)
+{
+	unsigned int gb, ratio;
+
+	/* Zone size in gigabytes */
+	gb = zone->present_pages >> (30 - PAGE_SHIFT);
+	if (gb)
+		ratio = int_sqrt(10 * gb);
+	else
+		ratio = 1;
+
+	zone->inactive_ratio = ratio;
+}
+
 static void __init setup_per_zone_inactive_ratio(void)
 {
 	struct zone *zone;
 
-	for_each_zone(zone) {
-		unsigned int gb, ratio;
-
-		/* Zone size in gigabytes */
-		gb = zone->present_pages >> (30 - PAGE_SHIFT);
-		if (gb)
-			ratio = int_sqrt(10 * gb);
-		else
-			ratio = 1;
-
-		zone->inactive_ratio = ratio;
-	}
+	for_each_zone(zone)
+		calculate_zone_inactive_ratio(zone);
 }
 
 /*