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-rw-r--r--mm/vmstat.c54
1 files changed, 49 insertions, 5 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 006eb762186..9832d9a41d8 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
}
}