1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_PAGE_COUNTER_H
3#define _LINUX_PAGE_COUNTER_H
4
5#include <linux/atomic.h>
6#include <linux/kernel.h>
7#include <asm/page.h>
8
9struct page_counter {
10 atomic_long_t usage;
11 unsigned long min;
12 unsigned long low;
13 unsigned long max;
14 struct page_counter *parent;
15
16 /* effective memory.min and memory.min usage tracking */
17 unsigned long emin;
18 atomic_long_t min_usage;
19 atomic_long_t children_min_usage;
20
21 /* effective memory.low and memory.low usage tracking */
22 unsigned long elow;
23 atomic_long_t low_usage;
24 atomic_long_t children_low_usage;
25
26 /* legacy */
27 unsigned long watermark;
28 unsigned long failcnt;
29};
30
31#if BITS_PER_LONG == 32
32#define PAGE_COUNTER_MAX LONG_MAX
33#else
34#define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE)
35#endif
36
37static inline void page_counter_init(struct page_counter *counter,
38 struct page_counter *parent)
39{
40 atomic_long_set(&counter->usage, 0);
41 counter->max = PAGE_COUNTER_MAX;
42 counter->parent = parent;
43}
44
45static inline unsigned long page_counter_read(struct page_counter *counter)
46{
47 return atomic_long_read(&counter->usage);
48}
49
50void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages);
51void page_counter_charge(struct page_counter *counter, unsigned long nr_pages);
52bool page_counter_try_charge(struct page_counter *counter,
53 unsigned long nr_pages,
54 struct page_counter **fail);
55void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
56void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages);
57void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages);
58int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages);
59int page_counter_memparse(const char *buf, const char *max,
60 unsigned long *nr_pages);
61
62static inline void page_counter_reset_watermark(struct page_counter *counter)
63{
64 counter->watermark = page_counter_read(counter);
65}
66
67#endif /* _LINUX_PAGE_COUNTER_H */
68