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C/C++ Source or Header  |  2008-12-24  |  3.3 KB  |  117 lines
  1. #ifndef __LINUX_PERCPU_H
  2. #define __LINUX_PERCPU_H
  3.  
  4. #include <linux/preempt.h>
  5. #include <linux/slab.h> /* For kmalloc() */
  6. #include <linux/smp.h>
  7. #include <linux/cpumask.h>
  8.  
  9. #include <asm/percpu.h>
  10.  
  11. #ifdef CONFIG_SMP
  12. #define DEFINE_PER_CPU(type, name)                    \
  13.     __attribute__((__section__(".data.percpu")))            \
  14.     PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  15.  
  16. #ifdef MODULE
  17. #define SHARED_ALIGNED_SECTION ".data.percpu"
  18. #else
  19. #define SHARED_ALIGNED_SECTION ".data.percpu.shared_aligned"
  20. #endif
  21.  
  22. #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)            \
  23.     __attribute__((__section__(SHARED_ALIGNED_SECTION)))        \
  24.     PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name        \
  25.     ____cacheline_aligned_in_smp
  26.  
  27. #define DEFINE_PER_CPU_PAGE_ALIGNED(type, name)            \
  28.     __attribute__((__section__(".data.percpu.page_aligned")))    \
  29.     PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  30. #else
  31. #define DEFINE_PER_CPU(type, name)                    \
  32.     PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  33.  
  34. #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)              \
  35.     DEFINE_PER_CPU(type, name)
  36.  
  37. #define DEFINE_PER_CPU_PAGE_ALIGNED(type, name)              \
  38.     DEFINE_PER_CPU(type, name)
  39. #endif
  40.  
  41. #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
  42. #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
  43.  
  44. /* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
  45. #ifndef PERCPU_ENOUGH_ROOM
  46. #ifdef CONFIG_MODULES
  47. #define PERCPU_MODULE_RESERVE    8192
  48. #else
  49. #define PERCPU_MODULE_RESERVE    0
  50. #endif
  51.  
  52. #define PERCPU_ENOUGH_ROOM                        \
  53.     (__per_cpu_end - __per_cpu_start + PERCPU_MODULE_RESERVE)
  54. #endif    /* PERCPU_ENOUGH_ROOM */
  55.  
  56. /*
  57.  * Must be an lvalue. Since @var must be a simple identifier,
  58.  * we force a syntax error here if it isn't.
  59.  */
  60. #define get_cpu_var(var) (*({                \
  61.     extern int simple_identifier_##var(void);    \
  62.     preempt_disable();                \
  63.     &__get_cpu_var(var); }))
  64. #define put_cpu_var(var) preempt_enable()
  65.  
  66. #ifdef CONFIG_SMP
  67.  
  68. struct percpu_data {
  69.     void *ptrs[1];
  70. };
  71.  
  72. #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
  73. /* 
  74.  * Use this to get to a cpu's version of the per-cpu object dynamically
  75.  * allocated. Non-atomic access to the current CPU's version should
  76.  * probably be combined with get_cpu()/put_cpu().
  77.  */ 
  78. #define percpu_ptr(ptr, cpu)                              \
  79. ({                                                        \
  80.         struct percpu_data *__p = __percpu_disguise(ptr); \
  81.         (__typeof__(ptr))__p->ptrs[(cpu)];              \
  82. })
  83.  
  84. extern void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask);
  85. extern void percpu_free(void *__pdata);
  86.  
  87. #else /* CONFIG_SMP */
  88.  
  89. #define percpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
  90.  
  91. static __always_inline void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
  92. {
  93.     return kzalloc(size, gfp);
  94. }
  95.  
  96. static inline void percpu_free(void *__pdata)
  97. {
  98.     kfree(__pdata);
  99. }
  100.  
  101. #endif /* CONFIG_SMP */
  102.  
  103. #define percpu_alloc_mask(size, gfp, mask) \
  104.     __percpu_alloc_mask((size), (gfp), &(mask))
  105.  
  106. #define percpu_alloc(size, gfp) percpu_alloc_mask((size), (gfp), cpu_online_map)
  107.  
  108. /* (legacy) interface for use without CPU hotplug handling */
  109.  
  110. #define __alloc_percpu(size)    percpu_alloc_mask((size), GFP_KERNEL, \
  111.                           cpu_possible_map)
  112. #define alloc_percpu(type)    (type *)__alloc_percpu(sizeof(type))
  113. #define free_percpu(ptr)    percpu_free((ptr))
  114. #define per_cpu_ptr(ptr, cpu)    percpu_ptr((ptr), (cpu))
  115.  
  116. #endif /* __LINUX_PERCPU_H */
  117.