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>
13 struct page_counter *parent;
15 /* effective memory.low and memory.low usage tracking */
17 atomic_long_t low_usage;
18 atomic_long_t children_low_usage;
21 unsigned long watermark;
22 unsigned long failcnt;
25 #if BITS_PER_LONG == 32
26 #define PAGE_COUNTER_MAX LONG_MAX
28 #define PAGE_COUNTER_MAX (LONG_MAX / PAGE_SIZE)
31 static inline void page_counter_init(struct page_counter *counter,
32 struct page_counter *parent)
34 atomic_long_set(&counter->usage, 0);
35 counter->max = PAGE_COUNTER_MAX;
36 counter->parent = parent;
39 static inline unsigned long page_counter_read(struct page_counter *counter)
41 return atomic_long_read(&counter->usage);
44 void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages);
45 void page_counter_charge(struct page_counter *counter, unsigned long nr_pages);
46 bool page_counter_try_charge(struct page_counter *counter,
47 unsigned long nr_pages,
48 struct page_counter **fail);
49 void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
50 int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages);
51 void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages);
52 int page_counter_memparse(const char *buf, const char *max,
53 unsigned long *nr_pages);
55 static inline void page_counter_reset_watermark(struct page_counter *counter)
57 counter->watermark = page_counter_read(counter);
60 #endif /* _LINUX_PAGE_COUNTER_H */