Move remote node draining out of slab allocators

[powerpc.git] / mm / vmstat.c

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 006eb76..9832d9a 100644 (file)
--- 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
        }
 }