2 * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
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.
14 #include <linux/gfp.h>
15 #include <linux/types.h>
18 * Flags to pass to kmem_cache_create().
19 * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
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_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
28 #define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
29 #define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
30 #define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */
32 /* Flag to prevent checks on free */
33 #ifdef CONFIG_DEBUG_OBJECTS
34 # define SLAB_DEBUG_OBJECTS 0x00400000UL
36 # define SLAB_DEBUG_OBJECTS 0x00000000UL
39 /* The following flags affect the page allocator grouping pages by mobility */
40 #define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
41 #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
43 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
45 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
47 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
48 * Both make kfree a no-op.
50 #define ZERO_SIZE_PTR ((void *)16)
52 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
53 (unsigned long)ZERO_SIZE_PTR)
56 * struct kmem_cache related prototypes
58 void __init kmem_cache_init(void);
59 int slab_is_available(void);
61 struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
63 void (*)(struct kmem_cache *, void *));
64 void kmem_cache_destroy(struct kmem_cache *);
65 int kmem_cache_shrink(struct kmem_cache *);
66 void kmem_cache_free(struct kmem_cache *, void *);
67 unsigned int kmem_cache_size(struct kmem_cache *);
68 const char *kmem_cache_name(struct kmem_cache *);
69 int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
72 * Please use this macro to create slab caches. Simply specify the
73 * name of the structure and maybe some flags that are listed above.
75 * The alignment of the struct determines object alignment. If you
76 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
77 * then the objects will be properly aligned in SMP configurations.
79 #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
80 sizeof(struct __struct), __alignof__(struct __struct),\
84 * The largest kmalloc size supported by the slab allocators is
85 * 32 megabyte (2^25) or the maximum allocatable page order if that is
88 * WARNING: Its not easy to increase this value since the allocators have
89 * to do various tricks to work around compiler limitations in order to
90 * ensure proper constant folding.
92 #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
93 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
95 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
96 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
99 * Common kmalloc functions provided by all allocators
101 void * __must_check krealloc(const void *, size_t, gfp_t);
102 void kfree(const void *);
103 size_t ksize(const void *);
106 * Allocator specific definitions. These are mainly used to establish optimized
107 * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
108 * selecting the appropriate general cache at compile time.
110 * Allocators must define at least:
116 * Those wishing to support NUMA must also define:
118 * kmem_cache_alloc_node()
121 * See each allocator definition file for additional comments and
122 * implementation notes.
125 #include <linux/slub_def.h>
126 #elif defined(CONFIG_SLOB)
127 #include <linux/slob_def.h>
129 #include <linux/slab_def.h>
133 * kcalloc - allocate memory for an array. The memory is set to zero.
134 * @n: number of elements.
135 * @size: element size.
136 * @flags: the type of memory to allocate.
138 * The @flags argument may be one of:
140 * %GFP_USER - Allocate memory on behalf of user. May sleep.
142 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
144 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
145 * For example, use this inside interrupt handlers.
147 * %GFP_HIGHUSER - Allocate pages from high memory.
149 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
151 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
153 * %GFP_NOWAIT - Allocation will not sleep.
155 * %GFP_THISNODE - Allocate node-local memory only.
157 * %GFP_DMA - Allocation suitable for DMA.
158 * Should only be used for kmalloc() caches. Otherwise, use a
159 * slab created with SLAB_DMA.
161 * Also it is possible to set different flags by OR'ing
162 * in one or more of the following additional @flags:
164 * %__GFP_COLD - Request cache-cold pages instead of
165 * trying to return cache-warm pages.
167 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
169 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
170 * (think twice before using).
172 * %__GFP_NORETRY - If memory is not immediately available,
173 * then give up at once.
175 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
177 * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
179 * There are other flags available as well, but these are not intended
180 * for general use, and so are not documented here. For a full list of
181 * potential flags, always refer to linux/gfp.h.
183 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
185 if (n != 0 && size > ULONG_MAX / n)
187 return __kmalloc(n * size, flags | __GFP_ZERO);
190 #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
192 * kmalloc_node - allocate memory from a specific node
193 * @size: how many bytes of memory are required.
194 * @flags: the type of memory to allocate (see kcalloc).
195 * @node: node to allocate from.
197 * kmalloc() for non-local nodes, used to allocate from a specific node
198 * if available. Equivalent to kmalloc() in the non-NUMA single-node
201 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
203 return kmalloc(size, flags);
206 static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
208 return __kmalloc(size, flags);
211 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
213 static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
214 gfp_t flags, int node)
216 return kmem_cache_alloc(cachep, flags);
218 #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
221 * kmalloc_track_caller is a special version of kmalloc that records the
222 * calling function of the routine calling it for slab leak tracking instead
223 * of just the calling function (confusing, eh?).
224 * It's useful when the call to kmalloc comes from a widely-used standard
225 * allocator where we care about the real place the memory allocation
226 * request comes from.
228 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
229 extern void *__kmalloc_track_caller(size_t, gfp_t, void*);
230 #define kmalloc_track_caller(size, flags) \
231 __kmalloc_track_caller(size, flags, __builtin_return_address(0))
233 #define kmalloc_track_caller(size, flags) \
234 __kmalloc(size, flags)
235 #endif /* DEBUG_SLAB */
239 * kmalloc_node_track_caller is a special version of kmalloc_node that
240 * records the calling function of the routine calling it for slab leak
241 * tracking instead of just the calling function (confusing, eh?).
242 * It's useful when the call to kmalloc_node comes from a widely-used
243 * standard allocator where we care about the real place the memory
244 * allocation request comes from.
246 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
247 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, void *);
248 #define kmalloc_node_track_caller(size, flags, node) \
249 __kmalloc_node_track_caller(size, flags, node, \
250 __builtin_return_address(0))
252 #define kmalloc_node_track_caller(size, flags, node) \
253 __kmalloc_node(size, flags, node)
256 #else /* CONFIG_NUMA */
258 #define kmalloc_node_track_caller(size, flags, node) \
259 kmalloc_track_caller(size, flags)
261 #endif /* DEBUG_SLAB */
266 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
268 return kmem_cache_alloc(k, flags | __GFP_ZERO);
272 * kzalloc - allocate memory. The memory is set to zero.
273 * @size: how many bytes of memory are required.
274 * @flags: the type of memory to allocate (see kmalloc).
276 static inline void *kzalloc(size_t size, gfp_t flags)
278 return kmalloc(size, flags | __GFP_ZERO);
281 #ifdef CONFIG_SLABINFO
282 extern const struct seq_operations slabinfo_op;
283 ssize_t slabinfo_write(struct file *, const char __user *, size_t, loff_t *);
286 #endif /* __KERNEL__ */
287 #endif /* _LINUX_SLAB_H */