2 * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
4 * (C) SGI 2006, Christoph Lameter
5 * Cleaned up and restructured to ease the addition of alternative
6 * implementations of SLAB allocators.
12 #include <linux/gfp.h>
13 #include <linux/types.h>
16 * Flags to pass to kmem_cache_create().
17 * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
19 #define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
20 #define SLAB_RED_ZONE 0x00000400UL /* DEBUG: Red zone objs in a cache */
21 #define SLAB_POISON 0x00000800UL /* DEBUG: Poison objects */
22 #define SLAB_HWCACHE_ALIGN 0x00002000UL /* Align objs on cache lines */
23 #define SLAB_CACHE_DMA 0x00004000UL /* Use GFP_DMA memory */
24 #define SLAB_STORE_USER 0x00010000UL /* DEBUG: Store the last owner for bug hunting */
25 #define SLAB_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
27 * SLAB_DESTROY_BY_RCU - **WARNING** READ THIS!
29 * This delays freeing the SLAB page by a grace period, it does _NOT_
30 * delay object freeing. This means that if you do kmem_cache_free()
31 * that memory location is free to be reused at any time. Thus it may
32 * be possible to see another object there in the same RCU grace period.
34 * This feature only ensures the memory location backing the object
35 * stays valid, the trick to using this is relying on an independent
36 * object validation pass. Something like:
40 * obj = lockless_lookup(key);
42 * if (!try_get_ref(obj)) // might fail for free objects
45 * if (obj->key != key) { // not the object we expected
52 * See also the comment on struct slab_rcu in mm/slab.c.
54 #define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
55 #define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
56 #define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */
58 /* Flag to prevent checks on free */
59 #ifdef CONFIG_DEBUG_OBJECTS
60 # define SLAB_DEBUG_OBJECTS 0x00400000UL
62 # define SLAB_DEBUG_OBJECTS 0x00000000UL
65 #define SLAB_NOLEAKTRACE 0x00800000UL /* Avoid kmemleak tracing */
67 /* Don't track use of uninitialized memory */
68 #ifdef CONFIG_KMEMCHECK
69 # define SLAB_NOTRACK 0x01000000UL
71 # define SLAB_NOTRACK 0x00000000UL
73 #ifdef CONFIG_FAILSLAB
74 # define SLAB_FAILSLAB 0x02000000UL /* Fault injection mark */
76 # define SLAB_FAILSLAB 0x00000000UL
79 /* The following flags affect the page allocator grouping pages by mobility */
80 #define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
81 #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
83 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
85 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
87 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
88 * Both make kfree a no-op.
90 #define ZERO_SIZE_PTR ((void *)16)
92 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
93 (unsigned long)ZERO_SIZE_PTR)
96 * Common fields provided in kmem_cache by all slab allocators
97 * This struct is either used directly by the allocator (SLOB)
98 * or the allocator must include definitions for all fields
99 * provided in kmem_cache_common in their definition of kmem_cache.
101 * Once we can do anonymous structs (C11 standard) we could put a
102 * anonymous struct definition in these allocators so that the
103 * separate allocations in the kmem_cache structure of SLAB and
104 * SLUB is no longer needed.
108 unsigned int object_size;/* The original size of the object */
109 unsigned int size; /* The aligned/padded/added on size */
110 unsigned int align; /* Alignment as calculated */
111 unsigned long flags; /* Active flags on the slab */
112 const char *name; /* Slab name for sysfs */
113 int refcount; /* Use counter */
114 void (*ctor)(void *); /* Called on object slot creation */
115 struct list_head list; /* List of all slab caches on the system */
120 * struct kmem_cache related prototypes
122 void __init kmem_cache_init(void);
123 int slab_is_available(void);
125 struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
128 void kmem_cache_destroy(struct kmem_cache *);
129 int kmem_cache_shrink(struct kmem_cache *);
130 void kmem_cache_free(struct kmem_cache *, void *);
133 * Please use this macro to create slab caches. Simply specify the
134 * name of the structure and maybe some flags that are listed above.
136 * The alignment of the struct determines object alignment. If you
137 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
138 * then the objects will be properly aligned in SMP configurations.
140 #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
141 sizeof(struct __struct), __alignof__(struct __struct),\
145 * The largest kmalloc size supported by the slab allocators is
146 * 32 megabyte (2^25) or the maximum allocatable page order if that is
149 * WARNING: Its not easy to increase this value since the allocators have
150 * to do various tricks to work around compiler limitations in order to
151 * ensure proper constant folding.
153 #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
154 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
156 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
157 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
160 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
161 * alignment larger than the alignment of a 64-bit integer.
162 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
164 #ifdef ARCH_DMA_MINALIGN
165 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
167 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
171 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
172 * Intended for arches that get misalignment faults even for 64 bit integer
175 #ifndef ARCH_SLAB_MINALIGN
176 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
180 * Common kmalloc functions provided by all allocators
182 void * __must_check __krealloc(const void *, size_t, gfp_t);
183 void * __must_check krealloc(const void *, size_t, gfp_t);
184 void kfree(const void *);
185 void kzfree(const void *);
186 size_t ksize(const void *);
189 * Allocator specific definitions. These are mainly used to establish optimized
190 * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
191 * selecting the appropriate general cache at compile time.
193 * Allocators must define at least:
199 * Those wishing to support NUMA must also define:
201 * kmem_cache_alloc_node()
204 * See each allocator definition file for additional comments and
205 * implementation notes.
208 #include <linux/slub_def.h>
209 #elif defined(CONFIG_SLOB)
210 #include <linux/slob_def.h>
212 #include <linux/slab_def.h>
216 * kmalloc_array - allocate memory for an array.
217 * @n: number of elements.
218 * @size: element size.
219 * @flags: the type of memory to allocate.
221 * The @flags argument may be one of:
223 * %GFP_USER - Allocate memory on behalf of user. May sleep.
225 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
227 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
228 * For example, use this inside interrupt handlers.
230 * %GFP_HIGHUSER - Allocate pages from high memory.
232 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
234 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
236 * %GFP_NOWAIT - Allocation will not sleep.
238 * %GFP_THISNODE - Allocate node-local memory only.
240 * %GFP_DMA - Allocation suitable for DMA.
241 * Should only be used for kmalloc() caches. Otherwise, use a
242 * slab created with SLAB_DMA.
244 * Also it is possible to set different flags by OR'ing
245 * in one or more of the following additional @flags:
247 * %__GFP_COLD - Request cache-cold pages instead of
248 * trying to return cache-warm pages.
250 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
252 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
253 * (think twice before using).
255 * %__GFP_NORETRY - If memory is not immediately available,
256 * then give up at once.
258 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
260 * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
262 * There are other flags available as well, but these are not intended
263 * for general use, and so are not documented here. For a full list of
264 * potential flags, always refer to linux/gfp.h.
266 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
268 if (size != 0 && n > SIZE_MAX / size)
270 return __kmalloc(n * size, flags);
274 * kcalloc - allocate memory for an array. The memory is set to zero.
275 * @n: number of elements.
276 * @size: element size.
277 * @flags: the type of memory to allocate (see kmalloc).
279 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
281 return kmalloc_array(n, size, flags | __GFP_ZERO);
284 #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
286 * kmalloc_node - allocate memory from a specific node
287 * @size: how many bytes of memory are required.
288 * @flags: the type of memory to allocate (see kcalloc).
289 * @node: node to allocate from.
291 * kmalloc() for non-local nodes, used to allocate from a specific node
292 * if available. Equivalent to kmalloc() in the non-NUMA single-node
295 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
297 return kmalloc(size, flags);
300 static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
302 return __kmalloc(size, flags);
305 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
307 static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
308 gfp_t flags, int node)
310 return kmem_cache_alloc(cachep, flags);
312 #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
315 * kmalloc_track_caller is a special version of kmalloc that records the
316 * calling function of the routine calling it for slab leak tracking instead
317 * of just the calling function (confusing, eh?).
318 * It's useful when the call to kmalloc comes from a widely-used standard
319 * allocator where we care about the real place the memory allocation
320 * request comes from.
322 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
323 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) || \
324 (defined(CONFIG_SLOB) && defined(CONFIG_TRACING))
325 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
326 #define kmalloc_track_caller(size, flags) \
327 __kmalloc_track_caller(size, flags, _RET_IP_)
329 #define kmalloc_track_caller(size, flags) \
330 __kmalloc(size, flags)
331 #endif /* DEBUG_SLAB */
335 * kmalloc_node_track_caller is a special version of kmalloc_node that
336 * records the calling function of the routine calling it for slab leak
337 * tracking instead of just the calling function (confusing, eh?).
338 * It's useful when the call to kmalloc_node comes from a widely-used
339 * standard allocator where we care about the real place the memory
340 * allocation request comes from.
342 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
343 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) || \
344 (defined(CONFIG_SLOB) && defined(CONFIG_TRACING))
345 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
346 #define kmalloc_node_track_caller(size, flags, node) \
347 __kmalloc_node_track_caller(size, flags, node, \
350 #define kmalloc_node_track_caller(size, flags, node) \
351 __kmalloc_node(size, flags, node)
354 #else /* CONFIG_NUMA */
356 #define kmalloc_node_track_caller(size, flags, node) \
357 kmalloc_track_caller(size, flags)
359 #endif /* CONFIG_NUMA */
364 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
366 return kmem_cache_alloc(k, flags | __GFP_ZERO);
370 * kzalloc - allocate memory. The memory is set to zero.
371 * @size: how many bytes of memory are required.
372 * @flags: the type of memory to allocate (see kmalloc).
374 static inline void *kzalloc(size_t size, gfp_t flags)
376 return kmalloc(size, flags | __GFP_ZERO);
380 * kzalloc_node - allocate zeroed memory from a particular memory node.
381 * @size: how many bytes of memory are required.
382 * @flags: the type of memory to allocate (see kmalloc).
383 * @node: memory node from which to allocate
385 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
387 return kmalloc_node(size, flags | __GFP_ZERO, node);
391 * Determine the size of a slab object
393 static inline unsigned int kmem_cache_size(struct kmem_cache *s)
395 return s->object_size;
398 void __init kmem_cache_init_late(void);
400 #endif /* _LINUX_SLAB_H */