summaryrefslogtreecommitdiffstats
path: root/include/linux/percpu.h
blob: d746a2abb322590a7e891762638e774ec0efe2b5 (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
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
#ifndef __LINUX_PERCPU_H
#define __LINUX_PERCPU_H

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

#include <asm/percpu.h>

#ifdef CONFIG_SMP
#define DEFINE_PER_CPU(type, name)					\
	__attribute__((__section__(".data.percpu")))			\
	PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name

#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)			\
	__attribute__((__section__(".data.percpu.shared_aligned")))	\
	PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name		\
	____cacheline_aligned_in_smp
#else
#define DEFINE_PER_CPU(type, name)					\
	PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name

#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		      \
	DEFINE_PER_CPU(type, name)
#endif

#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)

/* 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[1];
};

#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 */
OpenPOWER on IntegriCloud