diff options
Diffstat (limited to 'include/linux/slab.h')
| -rw-r--r-- | include/linux/slab.h | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h new file mode 100644 index 00000000..ad4dd1c8 --- /dev/null +++ b/include/linux/slab.h @@ -0,0 +1,336 @@ +/* + * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk). + * + * (C) SGI 2006, Christoph Lameter + * Cleaned up and restructured to ease the addition of alternative + * implementations of SLAB allocators. + */ + +#ifndef _LINUX_SLAB_H +#define _LINUX_SLAB_H + +#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_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */ +/* + * SLAB_DESTROY_BY_RCU - **WARNING** READ THIS! + * + * This delays freeing the SLAB page by a grace period, it does _NOT_ + * delay object freeing. This means that if you do kmem_cache_free() + * that memory location is free to be reused at any time. Thus it may + * be possible to see another object there in the same RCU grace period. + * + * This feature only ensures the memory location backing the object + * stays valid, the trick to using this is relying on an independent + * object validation pass. Something like: + * + * rcu_read_lock() + * again: + * obj = lockless_lookup(key); + * if (obj) { + * if (!try_get_ref(obj)) // might fail for free objects + * goto again; + * + * if (obj->key != key) { // not the object we expected + * put_ref(obj); + * goto again; + * } + * } + * rcu_read_unlock(); + * + * See also the comment on struct slab_rcu in mm/slab.c. + */ +#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 */ + +/* Flag to prevent checks on free */ +#ifdef CONFIG_DEBUG_OBJECTS +# define SLAB_DEBUG_OBJECTS 0x00400000UL +#else +# define SLAB_DEBUG_OBJECTS 0x00000000UL +#endif + +#define SLAB_NOLEAKTRACE 0x00800000UL /* Avoid kmemleak tracing */ + +/* Don't track use of uninitialized memory */ +#ifdef CONFIG_KMEMCHECK +# define SLAB_NOTRACK 0x01000000UL +#else +# define SLAB_NOTRACK 0x00000000UL +#endif +#ifdef CONFIG_FAILSLAB +# define SLAB_FAILSLAB 0x02000000UL /* Fault injection mark */ +#else +# define SLAB_FAILSLAB 0x00000000UL +#endif + +/* The following flags affect the page allocator grouping pages by mobility */ +#define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */ +#define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */ +/* + * 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 *)); +void kmem_cache_destroy(struct kmem_cache *); +int kmem_cache_shrink(struct kmem_cache *); +void kmem_cache_free(struct kmem_cache *, void *); +unsigned int kmem_cache_size(struct kmem_cache *); + +/* + * 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) + +/* + * 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 * __must_check __krealloc(const void *, size_t, gfp_t); +void * __must_check krealloc(const void *, size_t, gfp_t); +void kfree(const void *); +void kzfree(const void *); +size_t ksize(const void *); + +/* + * 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() + * + * 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 + +/** + * 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 (size != 0 && n > ULONG_MAX / size) + return NULL; + return __kmalloc(n * size, flags | __GFP_ZERO); +} + +#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) || \ + (defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) +extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long); +#define kmalloc_track_caller(size, flags) \ + __kmalloc_track_caller(size, flags, _RET_IP_) +#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) || \ + (defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) +extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long); +#define kmalloc_node_track_caller(size, flags, node) \ + __kmalloc_node_track_caller(size, flags, node, \ + _RET_IP_) +#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 /* CONFIG_NUMA */ + +/* + * Shortcuts + */ +static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags) +{ + return kmem_cache_alloc(k, flags | __GFP_ZERO); +} + +/** + * kzalloc - allocate memory. The memory is set to zero. + * @size: how many bytes of memory are required. + * @flags: the type of memory to allocate (see kmalloc). + */ +static inline void *kzalloc(size_t size, gfp_t flags) +{ + return kmalloc(size, flags | __GFP_ZERO); +} + +/** + * kzalloc_node - allocate zeroed memory from a particular memory node. + * @size: how many bytes of memory are required. + * @flags: the type of memory to allocate (see kmalloc). + * @node: memory node from which to allocate + */ +static inline void *kzalloc_node(size_t size, gfp_t flags, int node) +{ + return kmalloc_node(size, flags | __GFP_ZERO, node); +} + +void __init kmem_cache_init_late(void); + +#endif /* _LINUX_SLAB_H */ |