1 files changed, 22 insertions, 0 deletions

diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 7f43ccdc1d38..eaaea37b3b75 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -170,6 +170,28 @@ static inline unsigned long zone_page_state(struct zone *zone,
         return x;
 }
 
+/*
+ * More accurate version that also considers the currently pending
+ * deltas. For that we need to loop over all cpus to find the current
+ * deltas. There is no synchronization so the result cannot be
+ * exactly accurate either.
+ */
+static inline unsigned long zone_page_state_snapshot(struct zone *zone,
+                                        enum zone_stat_item item)
+{
+        long x = atomic_long_read(&zone->vm_stat[item]);
+
+#ifdef CONFIG_SMP
+        int cpu;
+        for_each_online_cpu(cpu)
+                x += per_cpu_ptr(zone->pageset, cpu)->vm_stat_diff[item];
+
+        if (x < 0)
+                x = 0;
+#endif
+        return x;
+}
+
 extern unsigned long global_reclaimable_pages(void);
 extern unsigned long zone_reclaimable_pages(struct zone *zone);