1#ifndef _LINUX_PAGE_COUNTER_H
2#define _LINUX_PAGE_COUNTER_H
3
4#include <linux/atomic.h>
5#include <linux/kernel.h>
6#include <asm/page.h>
7
8struct page_counter {
9	atomic_long_t count;
10	unsigned long limit;
11	struct page_counter *parent;
12
13	/* legacy */
14	unsigned long watermark;
15	unsigned long failcnt;
16};
17
18#if BITS_PER_LONG == 32
19#define PAGE_COUNTER_MAX LONG_MAX
20#else
21#define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE)
22#endif
23
24static inline void page_counter_init(struct page_counter *counter,
25				     struct page_counter *parent)
26{
27	atomic_long_set(&counter->count, 0);
28	counter->limit = PAGE_COUNTER_MAX;
29	counter->parent = parent;
30}
31
32static inline unsigned long page_counter_read(struct page_counter *counter)
33{
34	return atomic_long_read(&counter->count);
35}
36
37void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages);
38void page_counter_charge(struct page_counter *counter, unsigned long nr_pages);
39int page_counter_try_charge(struct page_counter *counter,
40			    unsigned long nr_pages,
41			    struct page_counter **fail);
42void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
43int page_counter_limit(struct page_counter *counter, unsigned long limit);
44int page_counter_memparse(const char *buf, const char *max,
45			  unsigned long *nr_pages);
46
47static inline void page_counter_reset_watermark(struct page_counter *counter)
48{
49	counter->watermark = page_counter_read(counter);
50}
51
52#endif /* _LINUX_PAGE_COUNTER_H */
53