[linux-2.6-block.git] / include / linux / slab.h

/*
 * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
 *
 * (C) SGI 2006, Christoph Lameter <clameter@sgi.com>
 * 	Cleaned up and restructured to ease the addition of alternative
 * 	implementations of SLAB allocators.
 */

#ifndef _LINUX_SLAB_H
#define	_LINUX_SLAB_H

#ifdef __KERNEL__

#include <linux/gfp.h>
#include <linux/types.h>

/*
 * Flags to pass to kmem_cache_create().
 * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
 */
#define SLAB_DEBUG_FREE		0x00000100UL	/* DEBUG: Perform (expensive) checks on free */
#define SLAB_RED_ZONE		0x00000400UL	/* DEBUG: Red zone objs in a cache */
#define SLAB_POISON		0x00000800UL	/* DEBUG: Poison objects */
#define SLAB_HWCACHE_ALIGN	0x00002000UL	/* Align objs on cache lines */
#define SLAB_CACHE_DMA		0x00004000UL	/* Use GFP_DMA memory */
#define SLAB_STORE_USER		0x00010000UL	/* DEBUG: Store the last owner for bug hunting */
#define SLAB_RECLAIM_ACCOUNT	0x00020000UL	/* Objects are reclaimable */
#define SLAB_PANIC		0x00040000UL	/* Panic if kmem_cache_create() fails */
#define SLAB_DESTROY_BY_RCU	0x00080000UL	/* Defer freeing slabs to RCU */
#define SLAB_MEM_SPREAD		0x00100000UL	/* Spread some memory over cpuset */
#define SLAB_TRACE		0x00200000UL	/* Trace allocations and frees */

/*
 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
 *
 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
 *
 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
 * Both make kfree a no-op.
 */
#define ZERO_SIZE_PTR ((void *)16)

#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) < \
				(unsigned long)ZERO_SIZE_PTR)

/*
 * struct kmem_cache related prototypes
 */
void __init kmem_cache_init(void);
int slab_is_available(void);

struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
			unsigned long,
			void (*)(void *, struct kmem_cache *, unsigned long),
			void (*)(void *, struct kmem_cache *, unsigned long));
void kmem_cache_destroy(struct kmem_cache *);
int kmem_cache_shrink(struct kmem_cache *);
void *kmem_cache_zalloc(struct kmem_cache *, gfp_t);
void kmem_cache_free(struct kmem_cache *, void *);
unsigned int kmem_cache_size(struct kmem_cache *);
const char *kmem_cache_name(struct kmem_cache *);
int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);

/*
 * Please use this macro to create slab caches. Simply specify the
 * name of the structure and maybe some flags that are listed above.
 *
 * The alignment of the struct determines object alignment. If you
 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
 * then the objects will be properly aligned in SMP configurations.
 */
#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
		sizeof(struct __struct), __alignof__(struct __struct),\
		(__flags), NULL, NULL)

/*
 * The largest kmalloc size supported by the slab allocators is
 * 32 megabyte (2^25) or the maximum allocatable page order if that is
 * less than 32 MB.
 *
 * WARNING: Its not easy to increase this value since the allocators have
 * to do various tricks to work around compiler limitations in order to
 * ensure proper constant folding.
 */
#define KMALLOC_SHIFT_HIGH	((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
				(MAX_ORDER + PAGE_SHIFT - 1) : 25)

#define KMALLOC_MAX_SIZE	(1UL << KMALLOC_SHIFT_HIGH)
#define KMALLOC_MAX_ORDER	(KMALLOC_SHIFT_HIGH - PAGE_SHIFT)

/*
 * Common kmalloc functions provided by all allocators
 */
void *__kzalloc(size_t, gfp_t);
void * __must_check krealloc(const void *, size_t, gfp_t);
void kfree(const void *);
size_t ksize(const void *);

/**
 * kcalloc - allocate memory for an array. The memory is set to zero.
 * @n: number of elements.
 * @size: element size.
 * @flags: the type of memory to allocate.
 *
 * The @flags argument may be one of:
 *
 * %GFP_USER - Allocate memory on behalf of user.  May sleep.
 *
 * %GFP_KERNEL - Allocate normal kernel ram.  May sleep.
 *
 * %GFP_ATOMIC - Allocation will not sleep.  May use emergency pools.
 *   For example, use this inside interrupt handlers.
 *
 * %GFP_HIGHUSER - Allocate pages from high memory.
 *
 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
 *
 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
 *
 * %GFP_NOWAIT - Allocation will not sleep.
 *
 * %GFP_THISNODE - Allocate node-local memory only.
 *
 * %GFP_DMA - Allocation suitable for DMA.
 *   Should only be used for kmalloc() caches. Otherwise, use a
 *   slab created with SLAB_DMA.
 *
 * Also it is possible to set different flags by OR'ing
 * in one or more of the following additional @flags:
 *
 * %__GFP_COLD - Request cache-cold pages instead of
 *   trying to return cache-warm pages.
 *
 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
 *
 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
 *   (think twice before using).
 *
 * %__GFP_NORETRY - If memory is not immediately available,
 *   then give up at once.
 *
 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
 *
 * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
 *
 * There are other flags available as well, but these are not intended
 * for general use, and so are not documented here. For a full list of
 * potential flags, always refer to linux/gfp.h.
 */
static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
{
	if (n != 0 && size > ULONG_MAX / n)
		return NULL;
	return __kzalloc(n * size, flags);
}

/*
 * Allocator specific definitions. These are mainly used to establish optimized
 * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
 * selecting the appropriate general cache at compile time.
 *
 * Allocators must define at least:
 *
 *	kmem_cache_alloc()
 *	__kmalloc()
 *	kmalloc()
 *	kzalloc()
 *
 * Those wishing to support NUMA must also define:
 *
 *	kmem_cache_alloc_node()
 *	kmalloc_node()
 *
 * See each allocator definition file for additional comments and
 * implementation notes.
 */
#ifdef CONFIG_SLUB
#include <linux/slub_def.h>
#elif defined(CONFIG_SLOB)
#include <linux/slob_def.h>
#else
#include <linux/slab_def.h>
#endif

#if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
/**
 * kmalloc_node - allocate memory from a specific node
 * @size: how many bytes of memory are required.
 * @flags: the type of memory to allocate (see kcalloc).
 * @node: node to allocate from.
 *
 * kmalloc() for non-local nodes, used to allocate from a specific node
 * if available. Equivalent to kmalloc() in the non-NUMA single-node
 * case.
 */
static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
{
	return kmalloc(size, flags);
}

static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
{
	return __kmalloc(size, flags);
}

void *kmem_cache_alloc(struct kmem_cache *, gfp_t);

static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
					gfp_t flags, int node)
{
	return kmem_cache_alloc(cachep, flags);
}
#endif /* !CONFIG_NUMA && !CONFIG_SLOB */

/*
 * kmalloc_track_caller is a special version of kmalloc that records the
 * calling function of the routine calling it for slab leak tracking instead
 * of just the calling function (confusing, eh?).
 * It's useful when the call to kmalloc comes from a widely-used standard
 * allocator where we care about the real place the memory allocation
 * request comes from.
 */
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
extern void *__kmalloc_track_caller(size_t, gfp_t, void*);
#define kmalloc_track_caller(size, flags) \
	__kmalloc_track_caller(size, flags, __builtin_return_address(0))
#else
#define kmalloc_track_caller(size, flags) \
	__kmalloc(size, flags)
#endif /* DEBUG_SLAB */

#ifdef CONFIG_NUMA
/*
 * kmalloc_node_track_caller is a special version of kmalloc_node that
 * records the calling function of the routine calling it for slab leak
 * tracking instead of just the calling function (confusing, eh?).
 * It's useful when the call to kmalloc_node comes from a widely-used
 * standard allocator where we care about the real place the memory
 * allocation request comes from.
 */
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, void *);
#define kmalloc_node_track_caller(size, flags, node) \
	__kmalloc_node_track_caller(size, flags, node, \
			__builtin_return_address(0))
#else
#define kmalloc_node_track_caller(size, flags, node) \
	__kmalloc_node(size, flags, node)
#endif

#else /* CONFIG_NUMA */

#define kmalloc_node_track_caller(size, flags, node) \
	kmalloc_track_caller(size, flags)

#endif /* DEBUG_SLAB */

#endif	/* __KERNEL__ */
#endif	/* _LINUX_SLAB_H */
Commit	Line	Data
1da177e4	1	/*
2e892f43 CL	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.
1da177e4 LT	7	*/
	8
	9	#ifndef _LINUX_SLAB_H
	10	#define _LINUX_SLAB_H
	11
1b1cec4b	12	#ifdef __KERNEL__
1da177e4	13
1b1cec4b	14	#include <linux/gfp.h>
1b1cec4b	15	#include <linux/types.h>
1da177e4	16
2e892f43 CL	17	/*
	18	* Flags to pass to kmem_cache_create().
	19	* The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
1da177e4	20	*/
55935a34	21	#define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
55935a34 CL	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 */
2e892f43	25	#define SLAB_CACHE_DMA 0x00004000UL /* Use GFP_DMA memory */
2e892f43 CL	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 */
101a5001	30	#define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
81819f0f	31	#define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */
1da177e4	32
6cb8f913 CL	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
2e892f43 CL	46	/*
	47	* struct kmem_cache related prototypes
	48	*/
	49	void __init kmem_cache_init(void);
81819f0f	50	int slab_is_available(void);
1da177e4	51
2e892f43	52	struct kmem_cache kmem_cache_create(const char , size_t, size_t,
ebe29738 CL	53	unsigned long,
	54	void ()(void , struct kmem_cache *, unsigned long),
	55	void ()(void , struct kmem_cache *, unsigned long));
2e892f43 CL	56	void kmem_cache_destroy(struct kmem_cache *);
2e892f43 CL	57	int kmem_cache_shrink(struct kmem_cache *);
2e892f43 CL	58	void kmem_cache_zalloc(struct kmem_cache , gfp_t);
	59	void kmem_cache_free(struct kmem_cache , void );
	60	unsigned int kmem_cache_size(struct kmem_cache *);
	61	const char kmem_cache_name(struct kmem_cache );
55935a34	62	int kmem_ptr_validate(struct kmem_cache cachep, const void ptr);
2e892f43	63
0a31bd5f CL	64	/*
	65	* Please use this macro to create slab caches. Simply specify the
	66	* name of the structure and maybe some flags that are listed above.
	67	*
	68	* The alignment of the struct determines object alignment. If you
	69	* f.e. add ____cacheline_aligned_in_smp to the struct declaration
	70	* then the objects will be properly aligned in SMP configurations.
	71	*/
	72	#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
	73	sizeof(struct __struct), __alignof__(struct __struct),\
	74	(__flags), NULL, NULL)
	75
0aa817f0 CL	76	/*
	77	* The largest kmalloc size supported by the slab allocators is
	78	* 32 megabyte (2^25) or the maximum allocatable page order if that is
	79	* less than 32 MB.
	80	*
	81	* WARNING: Its not easy to increase this value since the allocators have
	82	* to do various tricks to work around compiler limitations in order to
	83	* ensure proper constant folding.
	84	*/
debee076 CL	85	#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
debee076 CL	86	(MAX_ORDER + PAGE_SHIFT - 1) : 25)
0aa817f0 CL	87
	88	#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
	89	#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
	90
2e892f43 CL	91	/*
	92	* Common kmalloc functions provided by all allocators
	93	*/
2e892f43	94	void *__kzalloc(size_t, gfp_t);
fd76bab2	95	void * __must_check krealloc(const void *, size_t, gfp_t);
2e892f43	96	void kfree(const void *);
fd76bab2	97	size_t ksize(const void *);
2e892f43 CL	98
	99	/**
	100	* kcalloc - allocate memory for an array. The memory is set to zero.
	101	* @n: number of elements.
	102	* @size: element size.
	103	* @flags: the type of memory to allocate.
800590f5 PD	104	*
	105	* The @flags argument may be one of:
	106	*
	107	* %GFP_USER - Allocate memory on behalf of user. May sleep.
	108	*
	109	* %GFP_KERNEL - Allocate normal kernel ram. May sleep.
	110	*
6193a2ff	111	* %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
800590f5 PD	112	* For example, use this inside interrupt handlers.
	113	*
	114	* %GFP_HIGHUSER - Allocate pages from high memory.
	115	*
	116	* %GFP_NOIO - Do not do any I/O at all while trying to get memory.
	117	*
	118	* %GFP_NOFS - Do not make any fs calls while trying to get memory.
	119	*
6193a2ff PM	120	* %GFP_NOWAIT - Allocation will not sleep.
	121	*
	122	* %GFP_THISNODE - Allocate node-local memory only.
	123	*
	124	* %GFP_DMA - Allocation suitable for DMA.
	125	* Should only be used for kmalloc() caches. Otherwise, use a
	126	* slab created with SLAB_DMA.
	127	*
800590f5 PD	128	* Also it is possible to set different flags by OR'ing
	129	* in one or more of the following additional @flags:
	130	*
	131	* %__GFP_COLD - Request cache-cold pages instead of
	132	* trying to return cache-warm pages.
	133	*
800590f5 PD	134	* %__GFP_HIGH - This allocation has high priority and may use emergency pools.
800590f5 PD	135	*
800590f5 PD	136	* %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
	137	* (think twice before using).
	138	*
	139	* %__GFP_NORETRY - If memory is not immediately available,
	140	* then give up at once.
	141	*
	142	* %__GFP_NOWARN - If allocation fails, don't issue any warnings.
	143	*
	144	* %__GFP_REPEAT - If allocation fails initially, try once more before failing.
6193a2ff PM	145	*
	146	* There are other flags available as well, but these are not intended
	147	* for general use, and so are not documented here. For a full list of
	148	* potential flags, always refer to linux/gfp.h.
800590f5	149	*/
6193a2ff	150	static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
1da177e4	151	{
6193a2ff PM	152	if (n != 0 && size > ULONG_MAX / n)
	153	return NULL;
	154	return __kzalloc(n * size, flags);
1da177e4 LT	155	}
1da177e4 LT	156
6193a2ff PM	157	/*
	158	* Allocator specific definitions. These are mainly used to establish optimized
	159	* ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
	160	* selecting the appropriate general cache at compile time.
	161	*
	162	* Allocators must define at least:
	163	*
	164	* kmem_cache_alloc()
	165	* __kmalloc()
	166	* kmalloc()
	167	* kzalloc()
	168	*
	169	* Those wishing to support NUMA must also define:
	170	*
	171	* kmem_cache_alloc_node()
	172	* kmalloc_node()
	173	*
	174	* See each allocator definition file for additional comments and
	175	* implementation notes.
2e892f43	176	*/
6193a2ff PM	177	#ifdef CONFIG_SLUB
	178	#include <linux/slub_def.h>
	179	#elif defined(CONFIG_SLOB)
	180	#include <linux/slob_def.h>
	181	#else
	182	#include <linux/slab_def.h>
2e892f43 CL	183	#endif
2e892f43 CL	184
6193a2ff PM	185	#if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
	186	/**
	187	* kmalloc_node - allocate memory from a specific node
	188	* @size: how many bytes of memory are required.
	189	* @flags: the type of memory to allocate (see kcalloc).
	190	* @node: node to allocate from.
	191	*
	192	* kmalloc() for non-local nodes, used to allocate from a specific node
	193	* if available. Equivalent to kmalloc() in the non-NUMA single-node
	194	* case.
	195	*/
55935a34 CL	196	static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
	197	{
	198	return kmalloc(size, flags);
	199	}
	200
	201	static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
	202	{
	203	return __kmalloc(size, flags);
	204	}
6193a2ff PM	205
	206	void kmem_cache_alloc(struct kmem_cache , gfp_t);
	207
	208	static inline void kmem_cache_alloc_node(struct kmem_cache cachep,
	209	gfp_t flags, int node)
	210	{
	211	return kmem_cache_alloc(cachep, flags);
	212	}
	213	#endif /* !CONFIG_NUMA && !CONFIG_SLOB */
55935a34	214
1d2c8eea CH	215	/*
	216	* kmalloc_track_caller is a special version of kmalloc that records the
	217	* calling function of the routine calling it for slab leak tracking instead
	218	* of just the calling function (confusing, eh?).
	219	* It's useful when the call to kmalloc comes from a widely-used standard
	220	* allocator where we care about the real place the memory allocation
	221	* request comes from.
	222	*/
81819f0f	223	#if defined(CONFIG_DEBUG_SLAB) \|\| defined(CONFIG_SLUB)
1d2c8eea CH	224	extern void __kmalloc_track_caller(size_t, gfp_t, void);
	225	#define kmalloc_track_caller(size, flags) \
	226	__kmalloc_track_caller(size, flags, __builtin_return_address(0))
2e892f43 CL	227	#else
	228	#define kmalloc_track_caller(size, flags) \
	229	__kmalloc(size, flags)
	230	#endif /* DEBUG_SLAB */
1da177e4	231
97e2bde4	232	#ifdef CONFIG_NUMA
8b98c169 CH	233	/*
	234	* kmalloc_node_track_caller is a special version of kmalloc_node that
	235	* records the calling function of the routine calling it for slab leak
	236	* tracking instead of just the calling function (confusing, eh?).
	237	* It's useful when the call to kmalloc_node comes from a widely-used
	238	* standard allocator where we care about the real place the memory
	239	* allocation request comes from.
	240	*/
81819f0f	241	#if defined(CONFIG_DEBUG_SLAB) \|\| defined(CONFIG_SLUB)
8b98c169 CH	242	extern void __kmalloc_node_track_caller(size_t, gfp_t, int, void );
	243	#define kmalloc_node_track_caller(size, flags, node) \
	244	__kmalloc_node_track_caller(size, flags, node, \
	245	__builtin_return_address(0))
2e892f43 CL	246	#else
	247	#define kmalloc_node_track_caller(size, flags, node) \
	248	__kmalloc_node(size, flags, node)
8b98c169	249	#endif
2e892f43	250
8b98c169	251	#else /* CONFIG_NUMA */
8b98c169 CH	252
	253	#define kmalloc_node_track_caller(size, flags, node) \
	254	kmalloc_track_caller(size, flags)
97e2bde4	255
55935a34	256	#endif /* DEBUG_SLAB */
10cef602	257
1da177e4	258	#endif /* __KERNEL__ */
1da177e4	259	#endif /* _LINUX_SLAB_H */