include/linux/percpu.h

   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/string.h> /* For memset() */
   8 #include <linux/cpumask.h>
   9
  10 #include <asm/percpu.h>
  11
  12 #ifdef CONFIG_SMP
  13 #define DEFINE_PER_CPU(type, name)                                      \
  14         __attribute__((__section__(".data.percpu")))                    \
  15         PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  16
  17 #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)                       \
  18         __attribute__((__section__(".data.percpu.shared_aligned")))     \
  19         PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name             \
  20         ____cacheline_aligned_in_smp
  21 #else
  22 #define DEFINE_PER_CPU(type, name)                                      \
  23         PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  24
  25 #define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)                     \
  26         DEFINE_PER_CPU(type, name)
  27 #endif
  28
  29 #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
  30 #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
  31
  32 /* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
  33 #ifndef PERCPU_ENOUGH_ROOM
  34 #ifdef CONFIG_MODULES
  35 #define PERCPU_MODULE_RESERVE   8192
  36 #else
  37 #define PERCPU_MODULE_RESERVE   0
  38 #endif
  39
  40 #define PERCPU_ENOUGH_ROOM                                              \
  41         (__per_cpu_end - __per_cpu_start + PERCPU_MODULE_RESERVE)
  42 #endif  /* PERCPU_ENOUGH_ROOM */
  43
  44 /*
  45  * Must be an lvalue. Since @var must be a simple identifier,
  46  * we force a syntax error here if it isn't.
  47  */
  48 #define get_cpu_var(var) (*({                           \
  49         extern int simple_identifier_##var(void);       \
  50         preempt_disable();                              \
  51         &__get_cpu_var(var); }))
  52 #define put_cpu_var(var) preempt_enable()
  53
  54 #ifdef CONFIG_SMP
  55
  56 struct percpu_data {
  57         void *ptrs[1];
  58 };
  59
  60 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
  61 /*
  62  * Use this to get to a cpu's version of the per-cpu object dynamically
  63  * allocated. Non-atomic access to the current CPU's version should
  64  * probably be combined with get_cpu()/put_cpu().
  65  */
  66 #define percpu_ptr(ptr, cpu)                              \
  67 ({                                                        \
  68         struct percpu_data *__p = __percpu_disguise(ptr); \
  69         (__typeof__(ptr))__p->ptrs[(cpu)];                \
  70 })
  71
  72 extern void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu);
  73 extern void percpu_depopulate(void *__pdata, int cpu);
  74 extern int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
  75                                   cpumask_t *mask);
  76 extern void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask);
  77 extern void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask);
  78 extern void percpu_free(void *__pdata);
  79
  80 #else /* CONFIG_SMP */
  81
  82 #define percpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
  83
  84 static inline void percpu_depopulate(void *__pdata, int cpu)
  85 {
  86 }
  87
  88 static inline void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
  89 {
  90 }
  91
  92 static inline void *percpu_populate(void *__pdata, size_t size, gfp_t gfp,
  93                                     int cpu)
  94 {
  95         return percpu_ptr(__pdata, cpu);
  96 }
  97
  98 static inline int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
  99                                          cpumask_t *mask)
 100 {
 101         return 0;
 102 }
 103
 104 static __always_inline void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
 105 {
 106         return kzalloc(size, gfp);
 107 }
 108
 109 static inline void percpu_free(void *__pdata)
 110 {
 111         kfree(__pdata);
 112 }
 113
 114 #endif /* CONFIG_SMP */
 115
 116 #define percpu_populate_mask(__pdata, size, gfp, mask) \
 117         __percpu_populate_mask((__pdata), (size), (gfp), &(mask))
 118 #define percpu_depopulate_mask(__pdata, mask) \
 119         __percpu_depopulate_mask((__pdata), &(mask))
 120 #define percpu_alloc_mask(size, gfp, mask) \
 121         __percpu_alloc_mask((size), (gfp), &(mask))
 122
 123 #define percpu_alloc(size, gfp) percpu_alloc_mask((size), (gfp), cpu_online_map)
 124
 125 /* (legacy) interface for use without CPU hotplug handling */
 126
 127 #define __alloc_percpu(size)    percpu_alloc_mask((size), GFP_KERNEL, \
 128                                                   cpu_possible_map)
 129 #define alloc_percpu(type)      (type *)__alloc_percpu(sizeof(type))
 130 #define free_percpu(ptr)        percpu_free((ptr))
 131 #define per_cpu_ptr(ptr, cpu)   percpu_ptr((ptr), (cpu))
 132
 133 #endif /* __LINUX_PERCPU_H */