rcutiny.h 3.5 KB

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  1. /*
  2. * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
  3. *
  4. * This program is free software; you can redistribute it and/or modify
  5. * it under the terms of the GNU General Public License as published by
  6. * the Free Software Foundation; either version 2 of the License, or
  7. * (at your option) any later version.
  8. *
  9. * This program is distributed in the hope that it will be useful,
  10. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12. * GNU General Public License for more details.
  13. *
  14. * You should have received a copy of the GNU General Public License
  15. * along with this program; if not, write to the Free Software
  16. * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17. *
  18. * Copyright IBM Corporation, 2008
  19. *
  20. * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
  21. *
  22. * For detailed explanation of Read-Copy Update mechanism see -
  23. * Documentation/RCU
  24. */
  25. #ifndef __LINUX_TINY_H
  26. #define __LINUX_TINY_H
  27. #include <linux/cache.h>
  28. static inline void rcu_init(void)
  29. {
  30. }
  31. static inline void rcu_barrier_bh(void)
  32. {
  33. wait_rcu_gp(call_rcu_bh);
  34. }
  35. static inline void rcu_barrier_sched(void)
  36. {
  37. wait_rcu_gp(call_rcu_sched);
  38. }
  39. #ifdef CONFIG_TINY_RCU
  40. static inline void synchronize_rcu_expedited(void)
  41. {
  42. synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */
  43. }
  44. static inline void rcu_barrier(void)
  45. {
  46. rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */
  47. }
  48. #else /* #ifdef CONFIG_TINY_RCU */
  49. void synchronize_rcu_expedited(void);
  50. static inline void rcu_barrier(void)
  51. {
  52. wait_rcu_gp(call_rcu);
  53. }
  54. #endif /* #else #ifdef CONFIG_TINY_RCU */
  55. static inline void synchronize_rcu_bh(void)
  56. {
  57. synchronize_sched();
  58. }
  59. static inline void synchronize_rcu_bh_expedited(void)
  60. {
  61. synchronize_sched();
  62. }
  63. static inline void synchronize_sched_expedited(void)
  64. {
  65. synchronize_sched();
  66. }
  67. static inline void kfree_call_rcu(struct rcu_head *head,
  68. void (*func)(struct rcu_head *rcu))
  69. {
  70. call_rcu(head, func);
  71. }
  72. #ifdef CONFIG_TINY_RCU
  73. static inline void rcu_preempt_note_context_switch(void)
  74. {
  75. }
  76. static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
  77. {
  78. *delta_jiffies = ULONG_MAX;
  79. return 0;
  80. }
  81. #else /* #ifdef CONFIG_TINY_RCU */
  82. void rcu_preempt_note_context_switch(void);
  83. int rcu_preempt_needs_cpu(void);
  84. static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
  85. {
  86. *delta_jiffies = ULONG_MAX;
  87. return rcu_preempt_needs_cpu();
  88. }
  89. #endif /* #else #ifdef CONFIG_TINY_RCU */
  90. static inline void rcu_note_context_switch(int cpu)
  91. {
  92. rcu_sched_qs(cpu);
  93. rcu_preempt_note_context_switch();
  94. }
  95. /*
  96. * Take advantage of the fact that there is only one CPU, which
  97. * allows us to ignore virtualization-based context switches.
  98. */
  99. static inline void rcu_virt_note_context_switch(int cpu)
  100. {
  101. }
  102. /*
  103. * Return the number of grace periods.
  104. */
  105. static inline long rcu_batches_completed(void)
  106. {
  107. return 0;
  108. }
  109. /*
  110. * Return the number of bottom-half grace periods.
  111. */
  112. static inline long rcu_batches_completed_bh(void)
  113. {
  114. return 0;
  115. }
  116. static inline void rcu_force_quiescent_state(void)
  117. {
  118. }
  119. static inline void rcu_bh_force_quiescent_state(void)
  120. {
  121. }
  122. static inline void rcu_sched_force_quiescent_state(void)
  123. {
  124. }
  125. static inline void rcu_cpu_stall_reset(void)
  126. {
  127. }
  128. #ifdef CONFIG_DEBUG_LOCK_ALLOC
  129. extern int rcu_scheduler_active __read_mostly;
  130. extern void rcu_scheduler_starting(void);
  131. #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
  132. static inline void rcu_scheduler_starting(void)
  133. {
  134. }
  135. #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
  136. #endif /* __LINUX_RCUTINY_H */