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Johannes Weiner3e32cb22014-12-10 15:42:31 -08001#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
Johannes Weiner64f21992014-12-10 15:42:45 -080037void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages);
Johannes Weiner3e32cb22014-12-10 15:42:31 -080038void 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);
Johannes Weiner64f21992014-12-10 15:42:45 -080042void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
Johannes Weiner3e32cb22014-12-10 15:42:31 -080043int page_counter_limit(struct page_counter *counter, unsigned long limit);
Johannes Weiner650c5e52015-02-11 15:26:03 -080044int page_counter_memparse(const char *buf, const char *max,
45 unsigned long *nr_pages);
Johannes Weiner3e32cb22014-12-10 15:42:31 -080046
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 */