1. 根目录:
2. include
3. linux
4. vmstat.h

#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);

/*
 * vm counters are allowed to be racy. Use raw_cpu_ops to avoid the
 * local_irq_disable overhead.
 */
static inline void __count_vm_event(enum vm_event_item item)
{
	raw_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)
{
	raw_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 */

#ifdef CONFIG_DEBUG_TLBFLUSH
#define count_vm_tlb_event(x)	   count_vm_event(x)
#define count_vm_tlb_events(x, y)  count_vm_events(x, y)
#else
#define count_vm_tlb_event(x)     do {} while (0)
#define count_vm_tlb_events(x, y) do { (void)(y); } while (0)
#endif

#ifdef CONFIG_DEBUG_VM_VMACACHE
#define count_vm_vmacache_event(x) count_vm_event(x)
#else
#define count_vm_vmacache_event(x) do {} while (0)
#endif

#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;
}

#ifdef CONFIG_NUMA

extern unsigned long node_page_state(int node, enum zone_stat_item 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))

#ifdef CONFIG_SMP
void __mod_zone_page_state(struct zone *, enum zone_stat_item item, long);
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, long);
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 cpu_vm_stats_fold(int cpu);
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, long 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 __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 __inc_zone_page_state(struct page *page,
			enum zone_stat_item item)
{
	__inc_zone_state(page_zone(page), 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 inc_zone_state __inc_zone_state
#define dec_zone_state __dec_zone_state

#define set_pgdat_percpu_threshold(pgdat, callback) { }

static inline void refresh_zone_stat_thresholds(void) { }
static inline void cpu_vm_stats_fold(int cpu) { }

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 */