1 #ifndef __LINUX_PERCPU_H
2 #define __LINUX_PERCPU_H
4 #include <linux/preempt.h>
5 #include <linux/slab.h> /* For kmalloc() */
7 #include <linux/cpumask.h>
10 #include <asm/percpu.h>
12 /* enough to cover all DEFINE_PER_CPUs in modules */
14 #define PERCPU_MODULE_RESERVE (8 << 10)
16 #define PERCPU_MODULE_RESERVE 0
19 #ifndef PERCPU_ENOUGH_ROOM
20 #define PERCPU_ENOUGH_ROOM \
21 (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) + \
22 PERCPU_MODULE_RESERVE)
26 * Must be an lvalue. Since @var must be a simple identifier,
27 * we force a syntax error here if it isn't.
29 #define get_cpu_var(var) (*({ \
30 extern int simple_identifier_##var(void); \
32 &__get_cpu_var(var); }))
33 #define put_cpu_var(var) preempt_enable()
37 /* minimum unit size, also is the maximum supported allocation size */
38 #define PCPU_MIN_UNIT_SIZE PFN_ALIGN(64 << 10)
41 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
42 * back on the first chunk for dynamic percpu allocation if arch is
43 * manually allocating and mapping it for faster access (as a part of
44 * large page mapping for example).
46 * The following values give between one and two pages of free space
47 * after typical minimal boot (2-way SMP, single disk and NIC) with
48 * both defconfig and a distro config on x86_64 and 32. More
49 * intelligent way to determine this would be nice.
51 #if BITS_PER_LONG > 32
52 #define PERCPU_DYNAMIC_RESERVE (20 << 10)
54 #define PERCPU_DYNAMIC_RESERVE (12 << 10)
57 extern void *pcpu_base_addr;
58 extern const unsigned long *pcpu_unit_offsets;
60 struct pcpu_group_info {
61 int nr_units; /* aligned # of units */
62 unsigned long base_offset; /* base address offset */
63 unsigned int *cpu_map; /* unit->cpu map, empty
64 * entries contain NR_CPUS */
67 struct pcpu_alloc_info {
74 size_t __ai_size; /* internal, don't use */
75 int nr_groups; /* 0 if grouping unnecessary */
76 struct pcpu_group_info groups[];
86 extern const char *pcpu_fc_names[PCPU_FC_NR];
88 extern enum pcpu_fc pcpu_chosen_fc;
90 typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
92 typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
93 typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
94 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
96 extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
98 extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
100 extern struct pcpu_alloc_info * __init pcpu_build_alloc_info(
101 size_t reserved_size, ssize_t dyn_size,
103 pcpu_fc_cpu_distance_fn_t cpu_distance_fn);
105 extern int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
108 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
109 extern int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
111 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
112 pcpu_fc_alloc_fn_t alloc_fn,
113 pcpu_fc_free_fn_t free_fn);
116 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
117 extern int __init pcpu_page_first_chunk(size_t reserved_size,
118 pcpu_fc_alloc_fn_t alloc_fn,
119 pcpu_fc_free_fn_t free_fn,
120 pcpu_fc_populate_pte_fn_t populate_pte_fn);
124 * Use this to get to a cpu's version of the per-cpu object
125 * dynamically allocated. Non-atomic access to the current CPU's
126 * version should probably be combined with get_cpu()/put_cpu().
128 #define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
130 extern void *__alloc_reserved_percpu(size_t size, size_t align);
131 extern void *__alloc_percpu(size_t size, size_t align);
132 extern void free_percpu(void *__pdata);
134 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
135 extern void __init setup_per_cpu_areas(void);
138 #else /* CONFIG_SMP */
140 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
142 static inline void *__alloc_percpu(size_t size, size_t align)
145 * Can't easily make larger alignment work with kmalloc. WARN
146 * on it. Larger alignment should only be used for module
147 * percpu sections on SMP for which this path isn't used.
149 WARN_ON_ONCE(align > SMP_CACHE_BYTES);
150 return kzalloc(size, GFP_KERNEL);
153 static inline void free_percpu(void *p)
158 static inline void __init setup_per_cpu_areas(void) { }
160 static inline void *pcpu_lpage_remapped(void *kaddr)
165 #endif /* CONFIG_SMP */
167 #define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \
171 * Optional methods for optimized non-lvalue per-cpu variable access.
173 * @var can be a percpu variable or a field of it and its size should
174 * equal char, int or long. percpu_read() evaluates to a lvalue and
175 * all others to void.
177 * These operations are guaranteed to be atomic w.r.t. preemption.
178 * The generic versions use plain get/put_cpu_var(). Archs are
179 * encouraged to implement single-instruction alternatives which don't
180 * require preemption protection.
183 # define percpu_read(var) \
185 typeof(per_cpu_var(var)) __tmp_var__; \
186 __tmp_var__ = get_cpu_var(var); \
192 #define __percpu_generic_to_op(var, val, op) \
194 get_cpu_var(var) op val; \
199 # define percpu_write(var, val) __percpu_generic_to_op(var, (val), =)
203 # define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=)
207 # define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=)
211 # define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=)
215 # define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=)
219 # define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=)
222 #endif /* __LINUX_PERCPU_H */