1 files changed, 49 insertions, 5 deletions

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 006eb7621869..9832d9a41d8c 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -281,6 +281,17 @@ EXPORT_SYMBOL(dec_zone_page_state);
 
 /*
  * Update the zone counters for one cpu.
+ *
+ * Note that refresh_cpu_vm_stats strives to only access
+ * node local memory. The per cpu pagesets on remote zones are placed
+ * in the memory local to the processor using that pageset. So the
+ * loop over all zones will access a series of cachelines local to
+ * the processor.
+ *
+ * The call to zone_page_state_add updates the cachelines with the
+ * statistics in the remote zone struct as well as the global cachelines
+ * with the global counters. These could cause remote node cache line
+ * bouncing and will have to be only done when necessary.
  */
 void refresh_cpu_vm_stats(int cpu)
 {
@@ -289,21 +300,54 @@ void refresh_cpu_vm_stats(int cpu)
         unsigned long flags;
 
         for_each_zone(zone) {
-                struct per_cpu_pageset *pcp;
+                struct per_cpu_pageset *p;
 
                 if (!populated_zone(zone))
                         continue;
 
-                pcp = zone_pcp(zone, cpu);
+                p = zone_pcp(zone, cpu);
 
                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
-                        if (pcp->vm_stat_diff[i]) {
+                        if (p->vm_stat_diff[i]) {
                                 local_irq_save(flags);
-                                zone_page_state_add(pcp->vm_stat_diff[i],
+                                zone_page_state_add(p->vm_stat_diff[i],
                                         zone, i);
-                                pcp->vm_stat_diff[i] = 0;
+                                p->vm_stat_diff[i] = 0;
+#ifdef CONFIG_NUMA
+                                /* 3 seconds idle till flush */
+                                p->expire = 3;
+#endif
                                 local_irq_restore(flags);
                         }
+#ifdef CONFIG_NUMA
+                /*
+                 * Deal with draining the remote pageset of this
+                 * processor
+                 *
+                 * Check if there are pages remaining in this pageset
+                 * if not then there is nothing to expire.
+                 */
+                if (!p->expire || (!p->pcp[0].count && !p->pcp[1].count))
+                        continue;
+
+                /*
+                 * We never drain zones local to this processor.
+                 */
+                if (zone_to_nid(zone) == numa_node_id()) {
+                        p->expire = 0;
+                        continue;
+                }
+
+                p->expire--;
+                if (p->expire)
+                        continue;
+
+                if (p->pcp[0].count)
+                        drain_zone_pages(zone, p->pcp + 0);
+
+                if (p->pcp[1].count)
+                        drain_zone_pages(zone, p->pcp + 1);
+#endif
         }
 }