page_counter.h 2.1 KB

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