LXR linux/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/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#else
  27#define DEFINE_PER_CPU(type, name)                                      \
  28        PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
  29
  30#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)                     \
  31        DEFINE_PER_CPU(type, name)
  32#endif
  33
  34#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
  35#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
  36
  37/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
  38#ifndef PERCPU_ENOUGH_ROOM
  39#ifdef CONFIG_MODULES
  40#define PERCPU_MODULE_RESERVE   8192
  41#else
  42#define PERCPU_MODULE_RESERVE   0
  43#endif
  44
  45#define PERCPU_ENOUGH_ROOM                                              \
  46        (__per_cpu_end - __per_cpu_start + PERCPU_MODULE_RESERVE)
  47#endif  /* PERCPU_ENOUGH_ROOM */
  48
  49/*
  50 * Must be an lvalue. Since @var must be a simple identifier,
  51 * we force a syntax error here if it isn't.
  52 */
  53#define get_cpu_var(var) (*({                           \
  54        extern int simple_identifier_##var(void);       \
  55        preempt_disable();                              \
  56        &__get_cpu_var(var); }))
  57#define put_cpu_var(var) preempt_enable()
  58
  59#ifdef CONFIG_SMP
  60
  61struct percpu_data {
  62        void *ptrs[1];
  63};
  64
  65#define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
  66/* 
  67 * Use this to get to a cpu's version of the per-cpu object dynamically
  68 * allocated. Non-atomic access to the current CPU's version should
  69 * probably be combined with get_cpu()/put_cpu().
  70 */ 
  71#define percpu_ptr(ptr, cpu)                              \
  72({                                                        \
  73        struct percpu_data *__p = __percpu_disguise(ptr); \
  74        (__typeof__(ptr))__p->ptrs[(cpu)];                \
  75})
  76
  77extern void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask);
  78extern void percpu_free(void *__pdata);
  79
  80#else /* CONFIG_SMP */
  81
  82#define percpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
  83
  84static __always_inline void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
  85{
  86        return kzalloc(size, gfp);
  87}
  88
  89static inline void percpu_free(void *__pdata)
  90{
  91        kfree(__pdata);
  92}
  93
  94#endif /* CONFIG_SMP */
  95
  96#define percpu_alloc_mask(size, gfp, mask) \
  97        __percpu_alloc_mask((size), (gfp), &(mask))
  98
  99#define percpu_alloc(size, gfp) percpu_alloc_mask((size), (gfp), cpu_online_map)
 100
 101/* (legacy) interface for use without CPU hotplug handling */
 102
 103#define __alloc_percpu(size)    percpu_alloc_mask((size), GFP_KERNEL, \
 104                                                  cpu_possible_map)
 105#define alloc_percpu(type)      (type *)__alloc_percpu(sizeof(type))
 106#define free_percpu(ptr)        percpu_free((ptr))
 107#define per_cpu_ptr(ptr, cpu)   percpu_ptr((ptr), (cpu))
 108
 109#endif /* __LINUX_PERCPU_H */
 110