Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1#ifndef __LINUX_PERCPU_H
2#define __LINUX_PERCPU_H
3
4#include <linux/spinlock.h> /* For preempt_disable() */
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/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
13#ifndef PERCPU_ENOUGH_ROOM
14#ifdef CONFIG_MODULES
15#define PERCPU_MODULE_RESERVE 8192
16#else
17#define PERCPU_MODULE_RESERVE 0
18#endif
19
20#define PERCPU_ENOUGH_ROOM \
21 (__per_cpu_end - __per_cpu_start + PERCPU_MODULE_RESERVE)
22#endif /* PERCPU_ENOUGH_ROOM */
23
24/*
25 * Must be an lvalue. Since @var must be a simple identifier,
26 * we force a syntax error here if it isn't.
27 */
28#define get_cpu_var(var) (*({ \
29 extern int simple_identifier_##var(void); \
30 preempt_disable(); \
31 &__get_cpu_var(var); }))
32#define put_cpu_var(var) preempt_enable()
33
34#ifdef CONFIG_SMP
35
36struct percpu_data {
37 void *ptrs[NR_CPUS];
38};
39
40#define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
41/*
42 * Use this to get to a cpu's version of the per-cpu object dynamically
43 * allocated. Non-atomic access to the current CPU's version should
44 * probably be combined with get_cpu()/put_cpu().
45 */
46#define percpu_ptr(ptr, cpu) \
47({ \
48 struct percpu_data *__p = __percpu_disguise(ptr); \
49 (__typeof__(ptr))__p->ptrs[(cpu)]; \
50})
51
52extern void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu);
53extern void percpu_depopulate(void *__pdata, int cpu);
54extern int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
55 cpumask_t *mask);
56extern void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask);
57extern void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask);
58extern void percpu_free(void *__pdata);
59
60#else /* CONFIG_SMP */
61
62#define percpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
63
64static inline void percpu_depopulate(void *__pdata, int cpu)
65{
66}
67
68static inline void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
69{
70}
71
72static inline void *percpu_populate(void *__pdata, size_t size, gfp_t gfp,
73 int cpu)
74{
75 return percpu_ptr(__pdata, cpu);
76}
77
78static inline int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
79 cpumask_t *mask)
80{
81 return 0;
82}
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_populate_mask(__pdata, size, gfp, mask) \
97 __percpu_populate_mask((__pdata), (size), (gfp), &(mask))
98#define percpu_depopulate_mask(__pdata, mask) \
99 __percpu_depopulate_mask((__pdata), &(mask))
100#define percpu_alloc_mask(size, gfp, mask) \
101 __percpu_alloc_mask((size), (gfp), &(mask))
102
103#define percpu_alloc(size, gfp) percpu_alloc_mask((size), (gfp), cpu_online_map)
104
105/* (legacy) interface for use without CPU hotplug handling */
106
107#define __alloc_percpu(size) percpu_alloc_mask((size), GFP_KERNEL, \
108 cpu_possible_map)
109#define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type))
110#define free_percpu(ptr) percpu_free((ptr))
111#define per_cpu_ptr(ptr, cpu) percpu_ptr((ptr), (cpu))
112
113#endif /* __LINUX_PERCPU_H */