res_counter.h 4.0 KB

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  1. #ifndef __RES_COUNTER_H__
  2. #define __RES_COUNTER_H__
  3. /*
  4. * Resource Counters
  5. * Contain common data types and routines for resource accounting
  6. *
  7. * Copyright 2007 OpenVZ SWsoft Inc
  8. *
  9. * Author: Pavel Emelianov <xemul@openvz.org>
  10. *
  11. * See Documentation/controllers/resource_counter.txt for more
  12. * info about what this counter is.
  13. */
  14. #include <linux/cgroup.h>
  15. /*
  16. * The core object. the cgroup that wishes to account for some
  17. * resource may include this counter into its structures and use
  18. * the helpers described beyond
  19. */
  20. struct res_counter {
  21. /*
  22. * the current resource consumption level
  23. */
  24. unsigned long long usage;
  25. /*
  26. * the maximal value of the usage from the counter creation
  27. */
  28. unsigned long long max_usage;
  29. /*
  30. * the limit that usage cannot exceed
  31. */
  32. unsigned long long limit;
  33. /*
  34. * the number of unsuccessful attempts to consume the resource
  35. */
  36. unsigned long long failcnt;
  37. /*
  38. * the lock to protect all of the above.
  39. * the routines below consider this to be IRQ-safe
  40. */
  41. spinlock_t lock;
  42. };
  43. /**
  44. * Helpers to interact with userspace
  45. * res_counter_read_u64() - returns the value of the specified member.
  46. * res_counter_read/_write - put/get the specified fields from the
  47. * res_counter struct to/from the user
  48. *
  49. * @counter: the counter in question
  50. * @member: the field to work with (see RES_xxx below)
  51. * @buf: the buffer to opeate on,...
  52. * @nbytes: its size...
  53. * @pos: and the offset.
  54. */
  55. u64 res_counter_read_u64(struct res_counter *counter, int member);
  56. ssize_t res_counter_read(struct res_counter *counter, int member,
  57. const char __user *buf, size_t nbytes, loff_t *pos,
  58. int (*read_strategy)(unsigned long long val, char *s));
  59. typedef int (*write_strategy_fn)(const char *buf, unsigned long long *val);
  60. int res_counter_memparse_write_strategy(const char *buf,
  61. unsigned long long *res);
  62. int res_counter_write(struct res_counter *counter, int member,
  63. const char *buffer, write_strategy_fn write_strategy);
  64. /*
  65. * the field descriptors. one for each member of res_counter
  66. */
  67. enum {
  68. RES_USAGE,
  69. RES_MAX_USAGE,
  70. RES_LIMIT,
  71. RES_FAILCNT,
  72. };
  73. /*
  74. * helpers for accounting
  75. */
  76. void res_counter_init(struct res_counter *counter);
  77. /*
  78. * charge - try to consume more resource.
  79. *
  80. * @counter: the counter
  81. * @val: the amount of the resource. each controller defines its own
  82. * units, e.g. numbers, bytes, Kbytes, etc
  83. *
  84. * returns 0 on success and <0 if the counter->usage will exceed the
  85. * counter->limit _locked call expects the counter->lock to be taken
  86. */
  87. int __must_check res_counter_charge_locked(struct res_counter *counter,
  88. unsigned long val);
  89. int __must_check res_counter_charge(struct res_counter *counter,
  90. unsigned long val);
  91. /*
  92. * uncharge - tell that some portion of the resource is released
  93. *
  94. * @counter: the counter
  95. * @val: the amount of the resource
  96. *
  97. * these calls check for usage underflow and show a warning on the console
  98. * _locked call expects the counter->lock to be taken
  99. */
  100. void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
  101. void res_counter_uncharge(struct res_counter *counter, unsigned long val);
  102. static inline bool res_counter_limit_check_locked(struct res_counter *cnt)
  103. {
  104. if (cnt->usage < cnt->limit)
  105. return true;
  106. return false;
  107. }
  108. /*
  109. * Helper function to detect if the cgroup is within it's limit or
  110. * not. It's currently called from cgroup_rss_prepare()
  111. */
  112. static inline bool res_counter_check_under_limit(struct res_counter *cnt)
  113. {
  114. bool ret;
  115. unsigned long flags;
  116. spin_lock_irqsave(&cnt->lock, flags);
  117. ret = res_counter_limit_check_locked(cnt);
  118. spin_unlock_irqrestore(&cnt->lock, flags);
  119. return ret;
  120. }
  121. static inline void res_counter_reset_max(struct res_counter *cnt)
  122. {
  123. unsigned long flags;
  124. spin_lock_irqsave(&cnt->lock, flags);
  125. cnt->max_usage = cnt->usage;
  126. spin_unlock_irqrestore(&cnt->lock, flags);
  127. }
  128. static inline void res_counter_reset_failcnt(struct res_counter *cnt)
  129. {
  130. unsigned long flags;
  131. spin_lock_irqsave(&cnt->lock, flags);
  132. cnt->failcnt = 0;
  133. spin_unlock_irqrestore(&cnt->lock, flags);
  134. }
  135. #endif