1 files changed, 67 insertions, 106 deletions

diff --git a/mm/vmstat.c b/mm/vmstat.c
index f1400ba46beb..0e27b62e487d 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -31,8 +31,6 @@
 
 #include "internal.h"
 
-#define NUMA_STATS_THRESHOLD (U16_MAX - 2)
-
 #ifdef CONFIG_NUMA
 int sysctl_vm_numa_stat = ENABLE_NUMA_STAT;
 
@@ -41,11 +39,12 @@ static void zero_zone_numa_counters(struct zone *zone)
 {
 	int item, cpu;
 
-	for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++) {
-		atomic_long_set(&zone->vm_numa_stat[item], 0);
-		for_each_online_cpu(cpu)
-			per_cpu_ptr(zone->per_cpu_zonestats, cpu)->vm_numa_stat_diff[item]
+	for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++) {
+		atomic_long_set(&zone->vm_numa_event[item], 0);
+		for_each_online_cpu(cpu) {
+			per_cpu_ptr(zone->per_cpu_zonestats, cpu)->vm_numa_event[item]
 						= 0;
+		}
 	}
 }
 
@@ -63,8 +62,8 @@ static void zero_global_numa_counters(void)
 {
 	int item;
 
-	for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++)
-		atomic_long_set(&vm_numa_stat[item], 0);
+	for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
+		atomic_long_set(&vm_numa_event[item], 0);
 }
 
 static void invalid_numa_statistics(void)
@@ -161,10 +160,9 @@ void vm_events_fold_cpu(int cpu)
  * vm_stat contains the global counters
  */
 atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
-atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS] __cacheline_aligned_in_smp;
 atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
+atomic_long_t vm_numa_event[NR_VM_NUMA_EVENT_ITEMS] __cacheline_aligned_in_smp;
 EXPORT_SYMBOL(vm_zone_stat);
-EXPORT_SYMBOL(vm_numa_stat);
 EXPORT_SYMBOL(vm_node_stat);
 
 #ifdef CONFIG_SMP
@@ -706,8 +704,7 @@ EXPORT_SYMBOL(dec_node_page_state);
  * Fold a differential into the global counters.
  * Returns the number of counters updated.
  */
-#ifdef CONFIG_NUMA
-static int fold_diff(int *zone_diff, int *numa_diff, int *node_diff)
+static int fold_diff(int *zone_diff, int *node_diff)
 {
 	int i;
 	int changes = 0;
@@ -718,12 +715,6 @@ static int fold_diff(int *zone_diff, int *numa_diff, int *node_diff)
 			changes++;
 	}
 
-	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
-		if (numa_diff[i]) {
-			atomic_long_add(numa_diff[i], &vm_numa_stat[i]);
-			changes++;
-	}
-
 	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 		if (node_diff[i]) {
 			atomic_long_add(node_diff[i], &vm_node_stat[i]);
@@ -731,26 +722,34 @@ static int fold_diff(int *zone_diff, int *numa_diff, int *node_diff)
 	}
 	return changes;
 }
-#else
-static int fold_diff(int *zone_diff, int *node_diff)
+
+#ifdef CONFIG_NUMA
+static void fold_vm_zone_numa_events(struct zone *zone)
 {
-	int i;
-	int changes = 0;
+	unsigned long zone_numa_events[NR_VM_NUMA_EVENT_ITEMS] = { 0, };
+	int cpu;
+	enum numa_stat_item item;
 
-	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
-		if (zone_diff[i]) {
-			atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
-			changes++;
-	}
+	for_each_online_cpu(cpu) {
+		struct per_cpu_zonestat *pzstats;
 
-	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
-		if (node_diff[i]) {
-			atomic_long_add(node_diff[i], &vm_node_stat[i]);
-			changes++;
+		pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
+		for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
+			zone_numa_events[item] += xchg(&pzstats->vm_numa_event[item], 0);
 	}
-	return changes;
+
+	for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
+		zone_numa_event_add(zone_numa_events[item], zone, item);
 }
-#endif /* CONFIG_NUMA */
+
+void fold_vm_numa_events(void)
+{
+	struct zone *zone;
+
+	for_each_populated_zone(zone)
+		fold_vm_zone_numa_events(zone);
+}
+#endif
 
 /*
  * Update the zone counters for the current cpu.
@@ -774,9 +773,6 @@ static int refresh_cpu_vm_stats(bool do_pagesets)
 	struct zone *zone;
 	int i;
 	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
-#ifdef CONFIG_NUMA
-	int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
-#endif
 	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
 	int changes = 0;
 
@@ -801,17 +797,6 @@ static int refresh_cpu_vm_stats(bool do_pagesets)
 			}
 		}
 #ifdef CONFIG_NUMA
-		for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++) {
-			int v;
-
-			v = this_cpu_xchg(pzstats->vm_numa_stat_diff[i], 0);
-			if (v) {
-
-				atomic_long_add(v, &zone->vm_numa_stat[i]);
-				global_numa_diff[i] += v;
-				__this_cpu_write(pcp->expire, 3);
-			}
-		}
 
 		if (do_pagesets) {
 			cond_resched();
@@ -859,12 +844,7 @@ static int refresh_cpu_vm_stats(bool do_pagesets)
 		}
 	}
 
-#ifdef CONFIG_NUMA
-	changes += fold_diff(global_zone_diff, global_numa_diff,
-			     global_node_diff);
-#else
 	changes += fold_diff(global_zone_diff, global_node_diff);
-#endif
 	return changes;
 }
 
@@ -879,9 +859,6 @@ void cpu_vm_stats_fold(int cpu)
 	struct zone *zone;
 	int i;
 	int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
-#ifdef CONFIG_NUMA
-	int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
-#endif
 	int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
 
 	for_each_populated_zone(zone) {
@@ -889,7 +866,7 @@ void cpu_vm_stats_fold(int cpu)
 
 		pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
 
-		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
+		for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
 			if (pzstats->vm_stat_diff[i]) {
 				int v;
 
@@ -898,17 +875,17 @@ void cpu_vm_stats_fold(int cpu)
 				atomic_long_add(v, &zone->vm_stat[i]);
 				global_zone_diff[i] += v;
 			}
-
+		}
 #ifdef CONFIG_NUMA
-		for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
-			if (pzstats->vm_numa_stat_diff[i]) {
-				int v;
+		for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
+			if (pzstats->vm_numa_event[i]) {
+				unsigned long v;
 
-				v = pzstats->vm_numa_stat_diff[i];
-				pzstats->vm_numa_stat_diff[i] = 0;
-				atomic_long_add(v, &zone->vm_numa_stat[i]);
-				global_numa_diff[i] += v;
+				v = pzstats->vm_numa_event[i];
+				pzstats->vm_numa_event[i] = 0;
+				zone_numa_event_add(v, zone, i);
 			}
+		}
 #endif
 	}
 
@@ -928,11 +905,7 @@ void cpu_vm_stats_fold(int cpu)
 			}
 	}
 
-#ifdef CONFIG_NUMA
-	fold_diff(global_zone_diff, global_numa_diff, global_node_diff);
-#else
 	fold_diff(global_zone_diff, global_node_diff);
-#endif
 }
 
 /*
@@ -941,43 +914,37 @@ void cpu_vm_stats_fold(int cpu)
  */
 void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *pzstats)
 {
+	unsigned long v;
 	int i;
 
-	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
+	for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
 		if (pzstats->vm_stat_diff[i]) {
-			int v = pzstats->vm_stat_diff[i];
+			v = pzstats->vm_stat_diff[i];
 			pzstats->vm_stat_diff[i] = 0;
-			atomic_long_add(v, &zone->vm_stat[i]);
-			atomic_long_add(v, &vm_zone_stat[i]);
+			zone_page_state_add(v, zone, i);
 		}
+	}
 
 #ifdef CONFIG_NUMA
-	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
-		if (pzstats->vm_numa_stat_diff[i]) {
-			int v = pzstats->vm_numa_stat_diff[i];
-
-			pzstats->vm_numa_stat_diff[i] = 0;
-			atomic_long_add(v, &zone->vm_numa_stat[i]);
-			atomic_long_add(v, &vm_numa_stat[i]);
+	for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
+		if (pzstats->vm_numa_event[i]) {
+			v = pzstats->vm_numa_event[i];
+			pzstats->vm_numa_event[i] = 0;
+			zone_numa_event_add(v, zone, i);
 		}
+	}
 #endif
 }
 #endif
 
 #ifdef CONFIG_NUMA
-void __inc_numa_state(struct zone *zone,
+/* See __count_vm_event comment on why raw_cpu_inc is used. */
+void __count_numa_event(struct zone *zone,
 				 enum numa_stat_item item)
 {
 	struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats;
-	u16 __percpu *p = pzstats->vm_numa_stat_diff + item;
-	u16 v;
-
-	v = __this_cpu_inc_return(*p);
 
-	if (unlikely(v > NUMA_STATS_THRESHOLD)) {
-		zone_numa_state_add(v, zone, item);
-		__this_cpu_write(*p, 0);
-	}
+	raw_cpu_inc(pzstats->vm_numa_event[item]);
 }
 
 /*
@@ -998,19 +965,16 @@ unsigned long sum_zone_node_page_state(int node,
 	return count;
 }
 
-/*
- * Determine the per node value of a numa stat item. To avoid deviation,
- * the per cpu stat number in vm_numa_stat_diff[] is also included.
- */
-unsigned long sum_zone_numa_state(int node,
+/* Determine the per node value of a numa stat item. */
+unsigned long sum_zone_numa_event_state(int node,
 				 enum numa_stat_item item)
 {
 	struct zone *zones = NODE_DATA(node)->node_zones;
-	int i;
 	unsigned long count = 0;
+	int i;
 
 	for (i = 0; i < MAX_NR_ZONES; i++)
-		count += zone_numa_state_snapshot(zones + i, item);
+		count += zone_numa_event_state(zones + i, item);
 
 	return count;
 }
@@ -1689,9 +1653,9 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
 			   zone_page_state(zone, i));
 
 #ifdef CONFIG_NUMA
-	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
+	for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
 		seq_printf(m, "\n      %-12s %lu", numa_stat_name(i),
-			   zone_numa_state_snapshot(zone, i));
+			   zone_numa_event_state(zone, i));
 #endif
 
 	seq_printf(m, "\n  pagesets");
@@ -1745,7 +1709,7 @@ static const struct seq_operations zoneinfo_op = {
 };
 
 #define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
-			 NR_VM_NUMA_STAT_ITEMS + \
+			 NR_VM_NUMA_EVENT_ITEMS + \
 			 NR_VM_NODE_STAT_ITEMS + \
 			 NR_VM_WRITEBACK_STAT_ITEMS + \
 			 (IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
@@ -1760,6 +1724,7 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
 		return NULL;
 
 	BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS);
+	fold_vm_numa_events();
 	v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL);
 	m->private = v;
 	if (!v)
@@ -1769,9 +1734,9 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
 	v += NR_VM_ZONE_STAT_ITEMS;
 
 #ifdef CONFIG_NUMA
-	for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
-		v[i] = global_numa_state(i);
-	v += NR_VM_NUMA_STAT_ITEMS;
+	for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
+		v[i] = global_numa_event_state(i);
+	v += NR_VM_NUMA_EVENT_ITEMS;
 #endif
 
 	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
@@ -1941,11 +1906,7 @@ static bool need_update(int cpu)
 		if (memchr_inv(pzstats->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS *
 			       sizeof(pzstats->vm_stat_diff[0])))
 			return true;
-#ifdef CONFIG_NUMA
-		if (memchr_inv(pzstats->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS *
-			       sizeof(pzstats->vm_numa_stat_diff[0])))
-			return true;
-#endif
+
 		if (last_pgdat == zone->zone_pgdat)
 			continue;
 		last_pgdat = zone->zone_pgdat;