#ifndef _LINUX_VMSTAT_H
  #define _LINUX_VMSTAT_H
  
  #include <linux/types.h>
  #include <linux/percpu.h>

  #include <linux/mm.h>

  #include <linux/mmzone.h>

  #include <linux/vm_event_item.h>

  #include <linux/atomic.h>

  extern int sysctl_stat_interval;

  #ifdef CONFIG_VM_EVENT_COUNTERS
  /*
   * Light weight per cpu counter implementation.
   *
   * Counters should only be incremented and no critical kernel component
   * should rely on the counter values.
   *
   * Counters are handled completely inline. On many platforms the code
   * generated will simply be the increment of a global address.
   */

  struct vm_event_state {
  	unsigned long event[NR_VM_EVENT_ITEMS];

  };

  DECLARE_PER_CPU(struct vm_event_state, vm_event_states);
  
  static inline void __count_vm_event(enum vm_event_item item)
  {

  	__this_cpu_inc(vm_event_states.event[item]);

  }
  
  static inline void count_vm_event(enum vm_event_item item)
  {

  	this_cpu_inc(vm_event_states.event[item]);

  }
  
  static inline void __count_vm_events(enum vm_event_item item, long delta)
  {

  	__this_cpu_add(vm_event_states.event[item], delta);

  }
  
  static inline void count_vm_events(enum vm_event_item item, long delta)
  {

  	this_cpu_add(vm_event_states.event[item], delta);

  }
  
  extern void all_vm_events(unsigned long *);

  extern void vm_events_fold_cpu(int cpu);
  
  #else
  
  /* Disable counters */

  static inline void count_vm_event(enum vm_event_item item)
  {
  }
  static inline void count_vm_events(enum vm_event_item item, long delta)
  {
  }
  static inline void __count_vm_event(enum vm_event_item item)
  {
  }
  static inline void __count_vm_events(enum vm_event_item item, long delta)
  {
  }
  static inline void all_vm_events(unsigned long *ret)
  {
  }
  static inline void vm_events_fold_cpu(int cpu)
  {
  }

  
  #endif /* CONFIG_VM_EVENT_COUNTERS */

  #ifdef CONFIG_NUMA_BALANCING
  #define count_vm_numa_event(x)     count_vm_event(x)
  #define count_vm_numa_events(x, y) count_vm_events(x, y)
  #else
  #define count_vm_numa_event(x) do {} while (0)

  #define count_vm_numa_events(x, y) do { (void)(y); } while (0)

  #endif /* CONFIG_NUMA_BALANCING */

  #define __count_zone_vm_events(item, zone, delta) \

  		__count_vm_events(item##_NORMAL - ZONE_NORMAL + \
  		zone_idx(zone), delta)

  /*
   * Zone based page accounting with per cpu differentials.
   */
  extern atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
  
  static inline void zone_page_state_add(long x, struct zone *zone,
  				 enum zone_stat_item item)
  {
  	atomic_long_add(x, &zone->vm_stat[item]);
  	atomic_long_add(x, &vm_stat[item]);
  }
  
  static inline unsigned long global_page_state(enum zone_stat_item item)
  {
  	long x = atomic_long_read(&vm_stat[item]);
  #ifdef CONFIG_SMP
  	if (x < 0)
  		x = 0;
  #endif
  	return x;
  }
  
  static inline unsigned long zone_page_state(struct zone *zone,
  					enum zone_stat_item item)
  {
  	long x = atomic_long_read(&zone->vm_stat[item]);
  #ifdef CONFIG_SMP
  	if (x < 0)
  		x = 0;
  #endif
  	return x;
  }

  /*
   * More accurate version that also considers the currently pending
   * deltas. For that we need to loop over all cpus to find the current
   * deltas. There is no synchronization so the result cannot be
   * exactly accurate either.
   */
  static inline unsigned long zone_page_state_snapshot(struct zone *zone,
  					enum zone_stat_item item)
  {
  	long x = atomic_long_read(&zone->vm_stat[item]);
  
  #ifdef CONFIG_SMP
  	int cpu;
  	for_each_online_cpu(cpu)
  		x += per_cpu_ptr(zone->pageset, cpu)->vm_stat_diff[item];
  
  	if (x < 0)
  		x = 0;
  #endif
  	return x;
  }

  extern unsigned long global_reclaimable_pages(void);
  extern unsigned long zone_reclaimable_pages(struct zone *zone);

  #ifdef CONFIG_NUMA
  /*
   * Determine the per node value of a stat item. This function
   * is called frequently in a NUMA machine, so try to be as
   * frugal as possible.
   */
  static inline unsigned long node_page_state(int node,
  				 enum zone_stat_item item)
  {
  	struct zone *zones = NODE_DATA(node)->node_zones;
  
  	return

  #ifdef CONFIG_ZONE_DMA
  		zone_page_state(&zones[ZONE_DMA], item) +
  #endif

  #ifdef CONFIG_ZONE_DMA32

  		zone_page_state(&zones[ZONE_DMA32], item) +
  #endif

  #ifdef CONFIG_HIGHMEM
  		zone_page_state(&zones[ZONE_HIGHMEM], item) +
  #endif

  		zone_page_state(&zones[ZONE_NORMAL], item) +
  		zone_page_state(&zones[ZONE_MOVABLE], item);

  }

  extern void zone_statistics(struct zone *, struct zone *, gfp_t gfp);

  #else

  #define node_page_state(node, item) global_page_state(item)

  #define zone_statistics(_zl, _z, gfp) do { } while (0)

  
  #endif /* CONFIG_NUMA */

  #define add_zone_page_state(__z, __i, __d) mod_zone_page_state(__z, __i, __d)
  #define sub_zone_page_state(__z, __i, __d) mod_zone_page_state(__z, __i, -(__d))

  extern void inc_zone_state(struct zone *, enum zone_stat_item);

  #ifdef CONFIG_SMP
  void __mod_zone_page_state(struct zone *, enum zone_stat_item item, int);
  void __inc_zone_page_state(struct page *, enum zone_stat_item);
  void __dec_zone_page_state(struct page *, enum zone_stat_item);

  void mod_zone_page_state(struct zone *, enum zone_stat_item, int);
  void inc_zone_page_state(struct page *, enum zone_stat_item);
  void dec_zone_page_state(struct page *, enum zone_stat_item);
  
  extern void inc_zone_state(struct zone *, enum zone_stat_item);

  extern void __inc_zone_state(struct zone *, enum zone_stat_item);
  extern void dec_zone_state(struct zone *, enum zone_stat_item);
  extern void __dec_zone_state(struct zone *, enum zone_stat_item);

  
  void refresh_cpu_vm_stats(int);

  void refresh_zone_stat_thresholds(void);

  void drain_zonestat(struct zone *zone, struct per_cpu_pageset *);

  int calculate_pressure_threshold(struct zone *zone);
  int calculate_normal_threshold(struct zone *zone);
  void set_pgdat_percpu_threshold(pg_data_t *pgdat,
  				int (*calculate_pressure)(struct zone *));

  #else /* CONFIG_SMP */
  
  /*
   * We do not maintain differentials in a single processor configuration.
   * The functions directly modify the zone and global counters.
   */
  static inline void __mod_zone_page_state(struct zone *zone,
  			enum zone_stat_item item, int delta)
  {
  	zone_page_state_add(delta, zone, item);
  }

  static inline void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
  {
  	atomic_long_inc(&zone->vm_stat[item]);
  	atomic_long_inc(&vm_stat[item]);
  }

  static inline void __inc_zone_page_state(struct page *page,
  			enum zone_stat_item item)
  {

  	__inc_zone_state(page_zone(page), item);

  }

  static inline void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
  {
  	atomic_long_dec(&zone->vm_stat[item]);
  	atomic_long_dec(&vm_stat[item]);
  }

  static inline void __dec_zone_page_state(struct page *page,
  			enum zone_stat_item item)
  {

  	__dec_zone_state(page_zone(page), item);

  }
  
  /*
   * We only use atomic operations to update counters. So there is no need to
   * disable interrupts.
   */
  #define inc_zone_page_state __inc_zone_page_state
  #define dec_zone_page_state __dec_zone_page_state
  #define mod_zone_page_state __mod_zone_page_state

  #define set_pgdat_percpu_threshold(pgdat, callback) { }

  static inline void refresh_cpu_vm_stats(int cpu) { }

  static inline void refresh_zone_stat_thresholds(void) { }

  static inline void drain_zonestat(struct zone *zone,
  			struct per_cpu_pageset *pset) { }

  #endif		/* CONFIG_SMP */

  static inline void __mod_zone_freepage_state(struct zone *zone, int nr_pages,
  					     int migratetype)
  {
  	__mod_zone_page_state(zone, NR_FREE_PAGES, nr_pages);
  	if (is_migrate_cma(migratetype))
  		__mod_zone_page_state(zone, NR_FREE_CMA_PAGES, nr_pages);
  }

  extern const char * const vmstat_text[];

  
  #endif /* _LINUX_VMSTAT_H */