d385dbcf190b0806ab1a6eb1e5cba9cbc6ca88b3
[linux-2.6.git] / include / linux / percpu.h
1 #ifndef __LINUX_PERCPU_H
2 #define __LINUX_PERCPU_H
3
4 #include <linux/preempt.h>
5 #include <linux/slab.h> /* For kmalloc() */
6 #include <linux/smp.h>
7 #include <linux/cpumask.h>
8 #include <linux/pfn.h>
9
10 #include <asm/percpu.h>
11
12 /* enough to cover all DEFINE_PER_CPUs in modules */
13 #ifdef CONFIG_MODULES
14 #define PERCPU_MODULE_RESERVE           (8 << 10)
15 #else
16 #define PERCPU_MODULE_RESERVE           0
17 #endif
18
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)
23 #endif
24
25 /*
26  * Must be an lvalue. Since @var must be a simple identifier,
27  * we force a syntax error here if it isn't.
28  */
29 #define get_cpu_var(var) (*({                           \
30         extern int simple_identifier_##var(void);       \
31         preempt_disable();                              \
32         &__get_cpu_var(var); }))
33 #define put_cpu_var(var) preempt_enable()
34
35 #ifdef CONFIG_SMP
36
37 #ifndef CONFIG_HAVE_LEGACY_PER_CPU_AREA
38
39 /* minimum unit size, also is the maximum supported allocation size */
40 #define PCPU_MIN_UNIT_SIZE              PFN_ALIGN(64 << 10)
41
42 /*
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).
47  *
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.
52  */
53 #if BITS_PER_LONG > 32
54 #define PERCPU_DYNAMIC_RESERVE          (20 << 10)
55 #else
56 #define PERCPU_DYNAMIC_RESERVE          (12 << 10)
57 #endif
58
59 extern void *pcpu_base_addr;
60 extern const int *pcpu_unit_map;
61
62 enum pcpu_fc {
63         PCPU_FC_AUTO,
64         PCPU_FC_EMBED,
65         PCPU_FC_PAGE,
66         PCPU_FC_LPAGE,
67
68         PCPU_FC_NR,
69 };
70 extern const char *pcpu_fc_names[PCPU_FC_NR];
71
72 extern enum pcpu_fc pcpu_chosen_fc;
73
74 typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
75                                      size_t align);
76 typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
77 typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
78 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
79 typedef void (*pcpu_fc_map_fn_t)(void *ptr, size_t size, void *addr);
80
81 extern size_t __init pcpu_setup_first_chunk(
82                                 size_t static_size, size_t reserved_size,
83                                 size_t dyn_size, size_t unit_size,
84                                 void *base_addr, const int *unit_map);
85
86 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
87 extern ssize_t __init pcpu_embed_first_chunk(
88                                 size_t reserved_size, ssize_t dyn_size);
89 #endif
90
91 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
92 extern ssize_t __init pcpu_page_first_chunk(
93                                 size_t reserved_size,
94                                 pcpu_fc_alloc_fn_t alloc_fn,
95                                 pcpu_fc_free_fn_t free_fn,
96                                 pcpu_fc_populate_pte_fn_t populate_pte_fn);
97 #endif
98
99 #ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
100 extern int __init pcpu_lpage_build_unit_map(
101                                 size_t reserved_size, ssize_t *dyn_sizep,
102                                 size_t *unit_sizep, size_t lpage_size,
103                                 int *unit_map,
104                                 pcpu_fc_cpu_distance_fn_t cpu_distance_fn);
105
106 extern ssize_t __init pcpu_lpage_first_chunk(
107                                 size_t reserved_size, size_t dyn_size,
108                                 size_t unit_size, size_t lpage_size,
109                                 const int *unit_map, int nr_units,
110                                 pcpu_fc_alloc_fn_t alloc_fn,
111                                 pcpu_fc_free_fn_t free_fn,
112                                 pcpu_fc_map_fn_t map_fn);
113
114 extern void *pcpu_lpage_remapped(void *kaddr);
115 #else
116 static inline void *pcpu_lpage_remapped(void *kaddr)
117 {
118         return NULL;
119 }
120 #endif
121
122 /*
123  * Use this to get to a cpu's version of the per-cpu object
124  * dynamically allocated. Non-atomic access to the current CPU's
125  * version should probably be combined with get_cpu()/put_cpu().
126  */
127 #define per_cpu_ptr(ptr, cpu)   SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
128
129 extern void *__alloc_reserved_percpu(size_t size, size_t align);
130
131 #else /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */
132
133 struct percpu_data {
134         void *ptrs[1];
135 };
136
137 /* pointer disguising messes up the kmemleak objects tracking */
138 #ifndef CONFIG_DEBUG_KMEMLEAK
139 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
140 #else
141 #define __percpu_disguise(pdata) (struct percpu_data *)(pdata)
142 #endif
143
144 #define per_cpu_ptr(ptr, cpu)                                           \
145 ({                                                                      \
146         struct percpu_data *__p = __percpu_disguise(ptr);               \
147         (__typeof__(ptr))__p->ptrs[(cpu)];                              \
148 })
149
150 #endif /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */
151
152 extern void *__alloc_percpu(size_t size, size_t align);
153 extern void free_percpu(void *__pdata);
154
155 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
156 extern void __init setup_per_cpu_areas(void);
157 #endif
158
159 #else /* CONFIG_SMP */
160
161 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
162
163 static inline void *__alloc_percpu(size_t size, size_t align)
164 {
165         /*
166          * Can't easily make larger alignment work with kmalloc.  WARN
167          * on it.  Larger alignment should only be used for module
168          * percpu sections on SMP for which this path isn't used.
169          */
170         WARN_ON_ONCE(align > SMP_CACHE_BYTES);
171         return kzalloc(size, GFP_KERNEL);
172 }
173
174 static inline void free_percpu(void *p)
175 {
176         kfree(p);
177 }
178
179 static inline void __init setup_per_cpu_areas(void) { }
180
181 static inline void *pcpu_lpage_remapped(void *kaddr)
182 {
183         return NULL;
184 }
185
186 #endif /* CONFIG_SMP */
187
188 #define alloc_percpu(type)      (type *)__alloc_percpu(sizeof(type), \
189                                                        __alignof__(type))
190
191 /*
192  * Optional methods for optimized non-lvalue per-cpu variable access.
193  *
194  * @var can be a percpu variable or a field of it and its size should
195  * equal char, int or long.  percpu_read() evaluates to a lvalue and
196  * all others to void.
197  *
198  * These operations are guaranteed to be atomic w.r.t. preemption.
199  * The generic versions use plain get/put_cpu_var().  Archs are
200  * encouraged to implement single-instruction alternatives which don't
201  * require preemption protection.
202  */
203 #ifndef percpu_read
204 # define percpu_read(var)                                               \
205   ({                                                                    \
206         typeof(per_cpu_var(var)) __tmp_var__;                           \
207         __tmp_var__ = get_cpu_var(var);                                 \
208         put_cpu_var(var);                                               \
209         __tmp_var__;                                                    \
210   })
211 #endif
212
213 #define __percpu_generic_to_op(var, val, op)                            \
214 do {                                                                    \
215         get_cpu_var(var) op val;                                        \
216         put_cpu_var(var);                                               \
217 } while (0)
218
219 #ifndef percpu_write
220 # define percpu_write(var, val)         __percpu_generic_to_op(var, (val), =)
221 #endif
222
223 #ifndef percpu_add
224 # define percpu_add(var, val)           __percpu_generic_to_op(var, (val), +=)
225 #endif
226
227 #ifndef percpu_sub
228 # define percpu_sub(var, val)           __percpu_generic_to_op(var, (val), -=)
229 #endif
230
231 #ifndef percpu_and
232 # define percpu_and(var, val)           __percpu_generic_to_op(var, (val), &=)
233 #endif
234
235 #ifndef percpu_or
236 # define percpu_or(var, val)            __percpu_generic_to_op(var, (val), |=)
237 #endif
238
239 #ifndef percpu_xor
240 # define percpu_xor(var, val)           __percpu_generic_to_op(var, (val), ^=)
241 #endif
242
243 #endif /* __LINUX_PERCPU_H */