1 files changed, 15 insertions, 1 deletions

diff --git a/mm/vmstat.c b/mm/vmstat.c
index f389168f9a83..355a9e669aaa 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -138,11 +138,24 @@ static void refresh_zone_stat_thresholds(void)
         int threshold;
 
         for_each_populated_zone(zone) {
+                unsigned long max_drift, tolerate_drift;
+
                 threshold = calculate_threshold(zone);
 
                 for_each_online_cpu(cpu)
                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
                                                         = threshold;
+
+                /*
+                 * Only set percpu_drift_mark if there is a danger that
+                 * NR_FREE_PAGES reports the low watermark is ok when in fact
+                 * the min watermark could be breached by an allocation
+                 */
+                tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
+                max_drift = num_online_cpus() * threshold;
+                if (max_drift > tolerate_drift)
+                        zone->percpu_drift_mark = high_wmark_pages(zone) +
+                                        max_drift;
         }
 }
 
@@ -813,7 +826,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
                    "\n        scanned  %lu"
                    "\n        spanned  %lu"
                    "\n        present  %lu",
-                   zone_page_state(zone, NR_FREE_PAGES),
+                   zone_nr_free_pages(zone),
                    min_wmark_pages(zone),
                    low_wmark_pages(zone),
                    high_wmark_pages(zone),
@@ -998,6 +1011,7 @@ static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
         switch (action) {
         case CPU_ONLINE:
         case CPU_ONLINE_FROZEN:
+                refresh_zone_stat_thresholds();
                 start_cpu_timer(cpu);
                 node_set_state(cpu_to_node(cpu), N_CPU);
                 break;