/* * 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 /* 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 *); 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) /* * 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) 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) 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); } #endif /* _LINUX_SLAB_H */