diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 2eb5994..f451fed 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -117,4 +117,23 @@
 	return lru;
 }
 
+/**
+ * inactive_anon_is_low - check if anonymous pages need to be deactivated
+ * @zone: zone to check
+ *
+ * Returns true if the zone does not have enough inactive anon pages,
+ * meaning some active anon pages need to be deactivated.
+ */
+static inline int inactive_anon_is_low(struct zone *zone)
+{
+	unsigned long active, inactive;
+
+	active = zone_page_state(zone, NR_ACTIVE_ANON);
+	inactive = zone_page_state(zone, NR_INACTIVE_ANON);
+
+	if (inactive * zone->inactive_ratio < active)
+		return 1;
+
+	return 0;
+}
 #endif
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 59a4c8f..9c5111f 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -323,6 +323,12 @@
 	 */
 	int prev_priority;
 
+	/*
+	 * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on
+	 * this zone's LRU.  Maintained by the pageout code.
+	 */
+	unsigned int inactive_ratio;
+
 
 	ZONE_PADDING(_pad2_)
 	/* Rarely used or read-mostly fields */