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1/*
2 * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
3 *
4 * (C) SGI 2006, Christoph Lameter <clameter@sgi.com>
5 * Cleaned up and restructured to ease the addition of alternative
6 * implementations of SLAB allocators.
7 */
8
9#ifndef _LINUX_SLAB_H
10#define _LINUX_SLAB_H
11
12#ifdef __KERNEL__
13
14#include <linux/gfp.h>
15#include <linux/types.h>
16
17/*
18 * Flags to pass to kmem_cache_create().
19 * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
20 */
21#define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
22#define SLAB_RED_ZONE 0x00000400UL /* DEBUG: Red zone objs in a cache */
23#define SLAB_POISON 0x00000800UL /* DEBUG: Poison objects */
24#define SLAB_HWCACHE_ALIGN 0x00002000UL /* Align objs on cache lines */
25#define SLAB_CACHE_DMA 0x00004000UL /* Use GFP_DMA memory */
26#define SLAB_STORE_USER 0x00010000UL /* DEBUG: Store the last owner for bug hunting */
27#define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
28#define SLAB_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
29#define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
30#define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
31#define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */
32
33/*
34 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
35 *
36 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
37 *
38 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
39 * Both make kfree a no-op.
40 */
41#define ZERO_SIZE_PTR ((void *)16)
42
43#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
44 (unsigned long)ZERO_SIZE_PTR)
45
46/*
47 * struct kmem_cache related prototypes
48 */
49void __init kmem_cache_init(void);
50int slab_is_available(void);
51
52struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
53 unsigned long,
54 void (*)(void *, struct kmem_cache *, unsigned long));
55void kmem_cache_destroy(struct kmem_cache *);
56int kmem_cache_shrink(struct kmem_cache *);
57void kmem_cache_free(struct kmem_cache *, void *);
58unsigned int kmem_cache_size(struct kmem_cache *);
59const char *kmem_cache_name(struct kmem_cache *);
60int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
61
62/*
63 * Please use this macro to create slab caches. Simply specify the
64 * name of the structure and maybe some flags that are listed above.
65 *
66 * The alignment of the struct determines object alignment. If you
67 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
68 * then the objects will be properly aligned in SMP configurations.
69 */
70#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
71 sizeof(struct __struct), __alignof__(struct __struct),\
72 (__flags), NULL)
73
74/*
75 * The largest kmalloc size supported by the slab allocators is
76 * 32 megabyte (2^25) or the maximum allocatable page order if that is
77 * less than 32 MB.
78 *
79 * WARNING: Its not easy to increase this value since the allocators have
80 * to do various tricks to work around compiler limitations in order to
81 * ensure proper constant folding.
82 */
83#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
84 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
85
86#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
87#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
88
89/*
90 * Common kmalloc functions provided by all allocators
91 */
92void * __must_check krealloc(const void *, size_t, gfp_t);
93void kfree(const void *);
94size_t ksize(const void *);
95
96/*
97 * Allocator specific definitions. These are mainly used to establish optimized
98 * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
99 * selecting the appropriate general cache at compile time.
100 *
101 * Allocators must define at least:
102 *
103 * kmem_cache_alloc()
104 * __kmalloc()
105 * kmalloc()
106 *
107 * Those wishing to support NUMA must also define:
108 *
109 * kmem_cache_alloc_node()
110 * kmalloc_node()
111 *
112 * See each allocator definition file for additional comments and
113 * implementation notes.
114 */
115#ifdef CONFIG_SLUB
116#include <linux/slub_def.h>
117#elif defined(CONFIG_SLOB)
118#include <linux/slob_def.h>
119#else
120#include <linux/slab_def.h>
121#endif
122
123/**
124 * kcalloc - allocate memory for an array. The memory is set to zero.
125 * @n: number of elements.
126 * @size: element size.
127 * @flags: the type of memory to allocate.
128 *
129 * The @flags argument may be one of:
130 *
131 * %GFP_USER - Allocate memory on behalf of user. May sleep.
132 *
133 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
134 *
135 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
136 * For example, use this inside interrupt handlers.
137 *
138 * %GFP_HIGHUSER - Allocate pages from high memory.
139 *
140 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
141 *
142 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
143 *
144 * %GFP_NOWAIT - Allocation will not sleep.
145 *
146 * %GFP_THISNODE - Allocate node-local memory only.
147 *
148 * %GFP_DMA - Allocation suitable for DMA.
149 * Should only be used for kmalloc() caches. Otherwise, use a
150 * slab created with SLAB_DMA.
151 *
152 * Also it is possible to set different flags by OR'ing
153 * in one or more of the following additional @flags:
154 *
155 * %__GFP_COLD - Request cache-cold pages instead of
156 * trying to return cache-warm pages.
157 *
158 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
159 *
160 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
161 * (think twice before using).
162 *
163 * %__GFP_NORETRY - If memory is not immediately available,
164 * then give up at once.
165 *
166 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
167 *
168 * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
169 *
170 * There are other flags available as well, but these are not intended
171 * for general use, and so are not documented here. For a full list of
172 * potential flags, always refer to linux/gfp.h.
173 */
174static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
175{
176 if (n != 0 && size > ULONG_MAX / n)
177 return NULL;
178 return __kmalloc(n * size, flags | __GFP_ZERO);
179}
180
181#if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
182/**
183 * kmalloc_node - allocate memory from a specific node
184 * @size: how many bytes of memory are required.
185 * @flags: the type of memory to allocate (see kcalloc).
186 * @node: node to allocate from.
187 *
188 * kmalloc() for non-local nodes, used to allocate from a specific node
189 * if available. Equivalent to kmalloc() in the non-NUMA single-node
190 * case.
191 */
192static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
193{
194 return kmalloc(size, flags);
195}
196
197static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
198{
199 return __kmalloc(size, flags);
200}
201
202void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
203
204static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
205 gfp_t flags, int node)
206{
207 return kmem_cache_alloc(cachep, flags);
208}
209#endif /* !CONFIG_NUMA && !CONFIG_SLOB */
210
211/*
212 * kmalloc_track_caller is a special version of kmalloc that records the
213 * calling function of the routine calling it for slab leak tracking instead
214 * of just the calling function (confusing, eh?).
215 * It's useful when the call to kmalloc comes from a widely-used standard
216 * allocator where we care about the real place the memory allocation
217 * request comes from.
218 */
219#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
220extern void *__kmalloc_track_caller(size_t, gfp_t, void*);
221#define kmalloc_track_caller(size, flags) \
222 __kmalloc_track_caller(size, flags, __builtin_return_address(0))
223#else
224#define kmalloc_track_caller(size, flags) \
225 __kmalloc(size, flags)
226#endif /* DEBUG_SLAB */
227
228#ifdef CONFIG_NUMA
229/*
230 * kmalloc_node_track_caller is a special version of kmalloc_node that
231 * records the calling function of the routine calling it for slab leak
232 * tracking instead of just the calling function (confusing, eh?).
233 * It's useful when the call to kmalloc_node comes from a widely-used
234 * standard allocator where we care about the real place the memory
235 * allocation request comes from.
236 */
237#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
238extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, void *);
239#define kmalloc_node_track_caller(size, flags, node) \
240 __kmalloc_node_track_caller(size, flags, node, \
241 __builtin_return_address(0))
242#else
243#define kmalloc_node_track_caller(size, flags, node) \
244 __kmalloc_node(size, flags, node)
245#endif
246
247#else /* CONFIG_NUMA */
248
249#define kmalloc_node_track_caller(size, flags, node) \
250 kmalloc_track_caller(size, flags)
251
252#endif /* DEBUG_SLAB */
253
254/*
255 * Shortcuts
256 */
257static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
258{
259 return kmem_cache_alloc(k, flags | __GFP_ZERO);
260}
261
262/**
263 * kzalloc - allocate memory. The memory is set to zero.
264 * @size: how many bytes of memory are required.
265 * @flags: the type of memory to allocate (see kmalloc).
266 */
267static inline void *kzalloc(size_t size, gfp_t flags)
268{
269 return kmalloc(size, flags | __GFP_ZERO);
270}
271
272#endif /* __KERNEL__ */
273#endif /* _LINUX_SLAB_H */