aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/percpu.h
blob: 926adaae0f9610885d5d64e341410a9b96900312 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
#ifndef __LINUX_PERCPU_H
#define __LINUX_PERCPU_H

#include <linux/preempt.h>
#include <linux/slab.h> /* For kmalloc() */
#include <linux/smp.h>
#include <linux/string.h> /* For memset() */
#include <linux/cpumask.h>

#include <asm/percpu.h>

/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
#ifndef PERCPU_ENOUGH_ROOM
#ifdef CONFIG_MODULES
#define PERCPU_MODULE_RESERVE	8192
#else
#define PERCPU_MODULE_RESERVE	0
#endif

#define PERCPU_ENOUGH_ROOM						\
	(__per_cpu_end - __per_cpu_start + PERCPU_MODULE_RESERVE)
#endif	/* PERCPU_ENOUGH_ROOM */

/*
 * Must be an lvalue. Since @var must be a simple identifier,
 * we force a syntax error here if it isn't.
 */
#define get_cpu_var(var) (*({				\
	extern int simple_identifier_##var(void);	\
	preempt_disable();				\
	&__get_cpu_var(var); }))
#define put_cpu_var(var) preempt_enable()

#ifdef CONFIG_SMP

struct percpu_data {
	void *ptrs[NR_CPUS];
};

#define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
/* 
 * Use this to get to a cpu's version of the per-cpu object dynamically
 * allocated. Non-atomic access to the current CPU's version should
 * probably be combined with get_cpu()/put_cpu().
 */ 
#define percpu_ptr(ptr, cpu)                              \
({                                                        \
        struct percpu_data *__p = __percpu_disguise(ptr); \
        (__typeof__(ptr))__p->ptrs[(cpu)];	          \
})

extern void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu);
extern void percpu_depopulate(void *__pdata, int cpu);
extern int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
				  cpumask_t *mask);
extern void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask);
extern void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask);
extern void percpu_free(void *__pdata);

#else /* CONFIG_SMP */

#define percpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })

static inline void percpu_depopulate(void *__pdata, int cpu)
{
}

static inline void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
{
}

static inline void *percpu_populate(void *__pdata, size_t size, gfp_t gfp,
				    int cpu)
{
	return percpu_ptr(__pdata, cpu);
}

static inline int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
					 cpumask_t *mask)
{
	return 0;
}

static __always_inline void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
{
	return kzalloc(size, gfp);
}

static inline void percpu_free(void *__pdata)
{
	kfree(__pdata);
}

#endif /* CONFIG_SMP */

#define percpu_populate_mask(__pdata, size, gfp, mask) \
	__percpu_populate_mask((__pdata), (size), (gfp), &(mask))
#define percpu_depopulate_mask(__pdata, mask) \
	__percpu_depopulate_mask((__pdata), &(mask))
#define percpu_alloc_mask(size, gfp, mask) \
	__percpu_alloc_mask((size), (gfp), &(mask))

#define percpu_alloc(size, gfp) percpu_alloc_mask((size), (gfp), cpu_online_map)

/* (legacy) interface for use without CPU hotplug handling */

#define __alloc_percpu(size)	percpu_alloc_mask((size), GFP_KERNEL, \
						  cpu_possible_map)
#define alloc_percpu(type)	(type *)__alloc_percpu(sizeof(type))
#define free_percpu(ptr)	percpu_free((ptr))
#define per_cpu_ptr(ptr, cpu)	percpu_ptr((ptr), (cpu))

#endif /* __LINUX_PERCPU_H */