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 #ifndef CONFIG_HAVE_LEGACY_PER_CPU_AREA
39 /* minimum unit size, also is the maximum supported allocation size */
40 #define PCPU_MIN_UNIT_SIZE PFN_ALIGN(64 << 10)
43 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
44 * back on the first chunk for dynamic percpu allocation if arch is
45 * manually allocating and mapping it for faster access (as a part of
46 * large page mapping for example).
48 * The following values give between one and two pages of free space
49 * after typical minimal boot (2-way SMP, single disk and NIC) with
50 * both defconfig and a distro config on x86_64 and 32. More
51 * intelligent way to determine this would be nice.
53 #if BITS_PER_LONG > 32
54 #define PERCPU_DYNAMIC_RESERVE (20 << 10)
56 #define PERCPU_DYNAMIC_RESERVE (12 << 10)
59 extern void *pcpu_base_addr;
61 typedef struct page * (*pcpu_get_page_fn_t)(unsigned int cpu, int pageno);
62 typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size);
63 typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
64 typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
66 extern size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
67 size_t static_size, size_t reserved_size,
68 ssize_t dyn_size, ssize_t unit_size,
70 pcpu_fc_populate_pte_fn_t populate_pte_fn);
72 extern ssize_t __init pcpu_embed_first_chunk(
73 size_t static_size, size_t reserved_size,
76 extern ssize_t __init pcpu_4k_first_chunk(
77 size_t static_size, size_t reserved_size,
78 pcpu_fc_alloc_fn_t alloc_fn,
79 pcpu_fc_free_fn_t free_fn,
80 pcpu_fc_populate_pte_fn_t populate_pte_fn);
83 * Use this to get to a cpu's version of the per-cpu object
84 * dynamically allocated. Non-atomic access to the current CPU's
85 * version should probably be combined with get_cpu()/put_cpu().
87 #define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
89 extern void *__alloc_reserved_percpu(size_t size, size_t align);
91 #else /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */
97 /* pointer disguising messes up the kmemleak objects tracking */
98 #ifndef CONFIG_DEBUG_KMEMLEAK
99 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
101 #define __percpu_disguise(pdata) (struct percpu_data *)(pdata)
104 #define per_cpu_ptr(ptr, cpu) \
106 struct percpu_data *__p = __percpu_disguise(ptr); \
107 (__typeof__(ptr))__p->ptrs[(cpu)]; \
110 #endif /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */
112 extern void *__alloc_percpu(size_t size, size_t align);
113 extern void free_percpu(void *__pdata);
115 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
116 extern void __init setup_per_cpu_areas(void);
119 #else /* CONFIG_SMP */
121 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
123 static inline void *__alloc_percpu(size_t size, size_t align)
126 * Can't easily make larger alignment work with kmalloc. WARN
127 * on it. Larger alignment should only be used for module
128 * percpu sections on SMP for which this path isn't used.
130 WARN_ON_ONCE(align > SMP_CACHE_BYTES);
131 return kzalloc(size, GFP_KERNEL);
134 static inline void free_percpu(void *p)
139 static inline void __init setup_per_cpu_areas(void) { }
141 #endif /* CONFIG_SMP */
143 #define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \
147 * Optional methods for optimized non-lvalue per-cpu variable access.
149 * @var can be a percpu variable or a field of it and its size should
150 * equal char, int or long. percpu_read() evaluates to a lvalue and
151 * all others to void.
153 * These operations are guaranteed to be atomic w.r.t. preemption.
154 * The generic versions use plain get/put_cpu_var(). Archs are
155 * encouraged to implement single-instruction alternatives which don't
156 * require preemption protection.
159 # define percpu_read(var) \
161 typeof(per_cpu_var(var)) __tmp_var__; \
162 __tmp_var__ = get_cpu_var(var); \
168 #define __percpu_generic_to_op(var, val, op) \
170 get_cpu_var(var) op val; \
175 # define percpu_write(var, val) __percpu_generic_to_op(var, (val), =)
179 # define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=)
183 # define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=)
187 # define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=)
191 # define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=)
195 # define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=)
198 #endif /* __LINUX_PERCPU_H */