1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_PAGE_COUNTER_H
3 #define _LINUX_PAGE_COUNTER_H
5 #include <linux/atomic.h>
6 #include <linux/kernel.h>
15 struct page_counter *parent;
17 /* effective memory.min and memory.min usage tracking */
19 atomic_long_t min_usage;
20 atomic_long_t children_min_usage;
22 /* effective memory.low and memory.low usage tracking */
24 atomic_long_t low_usage;
25 atomic_long_t children_low_usage;
28 unsigned long watermark;
29 unsigned long failcnt;
32 #if BITS_PER_LONG == 32
33 #define PAGE_COUNTER_MAX LONG_MAX
35 #define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE)
38 static inline void page_counter_init(struct page_counter *counter,
39 struct page_counter *parent)
41 atomic_long_set(&counter->usage, 0);
42 counter->max = PAGE_COUNTER_MAX;
43 counter->parent = parent;
46 static inline unsigned long page_counter_read(struct page_counter *counter)
48 return atomic_long_read(&counter->usage);
51 void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages);
52 void page_counter_charge(struct page_counter *counter, unsigned long nr_pages);
53 bool page_counter_try_charge(struct page_counter *counter,
54 unsigned long nr_pages,
55 struct page_counter **fail);
56 void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
57 void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages);
58 void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages);
60 static inline void page_counter_set_high(struct page_counter *counter,
61 unsigned long nr_pages)
63 WRITE_ONCE(counter->high, nr_pages);
66 int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages);
67 int page_counter_memparse(const char *buf, const char *max,
68 unsigned long *nr_pages);
70 static inline void page_counter_reset_watermark(struct page_counter *counter)
72 counter->watermark = page_counter_read(counter);
75 #endif /* _LINUX_PAGE_COUNTER_H */