diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index 7e50aa2bd331..c086c5464dbb 100755
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -27,6 +27,22 @@
 #include <linux/module.h>
 #include <linux/vmpressure.h>
 
+/*
+ * The window size (vmpressure_win) is the number of scanned pages before
+ * we try to analyze scanned/reclaimed ratio. So the window is used as a
+ * rate-limit tunable for the "low" level notification, and also for
+ * averaging the ratio for medium/critical levels. Using small window
+ * sizes can cause lot of false positives, but too big window size will
+ * delay the notifications.
+ *
+ * As the vmscan reclaimer logic works with chunks which are multiple of
+ * SWAP_CLUSTER_MAX, it makes sense to use it for the window size as well.
+ *
+ * TODO: Make the window size depend on machine size, as we do for vmstat
+ * thresholds. Currently we set it to 512 pages (2MB for 4KB pages).
+ */
+static unsigned long vmpressure_win = SWAP_CLUSTER_MAX * 16;
+
 /*
  * These thresholds are used when we account memory pressure through
  * scanned/reclaimed ratio. The current values were chosen empirically. In
@@ -436,6 +452,29 @@ static void vmpressure_memcg(gfp_t gfp, struct mem_cgroup *memcg, bool tree,
 }
 #endif
 
+static void calculate_vmpressure_win(void)
+{
+	long x;
+
+	x = global_node_page_state(NR_FILE_PAGES) -
+			global_node_page_state(NR_SHMEM) -
+			total_swapcache_pages() +
+			global_zone_page_state(NR_FREE_PAGES);
+	if (x < 1)
+		x = 1;
+	/*
+	 * For low (free + cached), vmpressure window should be
+	 * small, and high for higher values of (free + cached).
+	 * But it should not be linear as well. This ensures
+	 * timely vmpressure notifications when system is under
+	 * memory pressure, and optimal number of events when
+	 * cached is high. The sqaure root function is empirically
+	 * found to serve the purpose.
+	 */
+	x = int_sqrt(x);
+	vmpressure_win = x;
+}
+
 static void vmpressure_global(gfp_t gfp, unsigned long scanned,
 		unsigned long reclaimed)
 {
@@ -450,6 +489,9 @@ static void vmpressure_global(gfp_t gfp, unsigned long scanned,
 		return;
 
 	spin_lock(&vmpr->sr_lock);
+	if (!vmpr->scanned)
+		calculate_vmpressure_win();
+
 	vmpr->scanned += scanned;
 	vmpr->reclaimed += reclaimed;