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Diffstat (limited to 'include/linux/slab.h')
| -rw-r--r-- | include/linux/slab.h | 544 |
1 files changed, 544 insertions, 0 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h new file mode 100644 index 000000000..a547077f8 --- /dev/null +++ b/include/linux/slab.h @@ -0,0 +1,544 @@ +/* + * 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> +#include <linux/workqueue.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 */ +#define SLAB_NO_DEBUG 0x10000000UL /* Disable slub debug for special cache */ +/* + * 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 mem_cgroup; +/* + * 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 * +kmem_cache_create_memcg(struct mem_cgroup *, const char *, size_t, size_t, + unsigned long, void (*)(void *), struct kmem_cache *); +void kmem_cache_destroy(struct kmem_cache *); +int kmem_cache_shrink(struct kmem_cache *); +void kmem_cache_free(struct kmem_cache *, void *); + +/* + * 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) + +/* + * 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 *); + +/* + * Some archs want to perform DMA into kmalloc caches and need a guaranteed + * alignment larger than the alignment of a 64-bit integer. + * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that. + */ +#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8 +#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN +#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN +#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN) +#else +#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) +#endif + +#ifdef CONFIG_SLOB +/* + * Common fields provided in kmem_cache by all slab allocators + * This struct is either used directly by the allocator (SLOB) + * or the allocator must include definitions for all fields + * provided in kmem_cache_common in their definition of kmem_cache. + * + * Once we can do anonymous structs (C11 standard) we could put a + * anonymous struct definition in these allocators so that the + * separate allocations in the kmem_cache structure of SLAB and + * SLUB is no longer needed. + */ +struct kmem_cache { + unsigned int object_size;/* The original size of the object */ + unsigned int size; /* The aligned/padded/added on size */ + unsigned int align; /* Alignment as calculated */ + unsigned long flags; /* Active flags on the slab */ + const char *name; /* Slab name for sysfs */ + int refcount; /* Use counter */ + void (*ctor)(void *); /* Called on object slot creation */ + struct list_head list; /* List of all slab caches on the system */ +}; + +#define KMALLOC_MAX_SIZE (1UL << 30) + +#include <linux/slob_def.h> + +#else /* CONFIG_SLOB */ + +/* + * Kmalloc array related definitions + */ + +#ifdef CONFIG_SLAB +/* + * 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_SHIFT_MAX KMALLOC_SHIFT_HIGH +#ifndef KMALLOC_SHIFT_LOW +#define KMALLOC_SHIFT_LOW 5 +#endif +#else +/* + * SLUB allocates up to order 2 pages directly and otherwise + * passes the request to the page allocator. + */ +#define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1) +#define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT) +#ifndef KMALLOC_SHIFT_LOW +#define KMALLOC_SHIFT_LOW 3 +#endif +#endif + +/* Maximum allocatable size */ +#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX) +/* Maximum size for which we actually use a slab cache */ +#define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH) +/* Maximum order allocatable via the slab allocagtor */ +#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT) + +/* + * Kmalloc subsystem. + */ +#ifndef KMALLOC_MIN_SIZE +#define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW) +#endif + +extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1]; +#ifdef CONFIG_ZONE_DMA +extern struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1]; +#endif + +/* + * Figure out which kmalloc slab an allocation of a certain size + * belongs to. + * 0 = zero alloc + * 1 = 65 .. 96 bytes + * 2 = 120 .. 192 bytes + * n = 2^(n-1) .. 2^n -1 + */ +static __always_inline int kmalloc_index(size_t size) +{ + if (!size) + return 0; + + if (size <= KMALLOC_MIN_SIZE) + return KMALLOC_SHIFT_LOW; + + if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96) + return 1; + if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192) + return 2; + if (size <= 8) return 3; + if (size <= 16) return 4; + if (size <= 32) return 5; + if (size <= 64) return 6; + if (size <= 128) return 7; + if (size <= 256) return 8; + if (size <= 512) return 9; + if (size <= 1024) return 10; + if (size <= 2 * 1024) return 11; + if (size <= 4 * 1024) return 12; + if (size <= 8 * 1024) return 13; + if (size <= 16 * 1024) return 14; + if (size <= 32 * 1024) return 15; + if (size <= 64 * 1024) return 16; + if (size <= 128 * 1024) return 17; + if (size <= 256 * 1024) return 18; + if (size <= 512 * 1024) return 19; + if (size <= 1024 * 1024) return 20; + if (size <= 2 * 1024 * 1024) return 21; + if (size <= 4 * 1024 * 1024) return 22; + if (size <= 8 * 1024 * 1024) return 23; + if (size <= 16 * 1024 * 1024) return 24; + if (size <= 32 * 1024 * 1024) return 25; + if (size <= 64 * 1024 * 1024) return 26; + BUG(); + + /* Will never be reached. Needed because the compiler may complain */ + return -1; +} + +#ifdef CONFIG_SLAB +#include <linux/slab_def.h> +#elif defined(CONFIG_SLUB) +#include <linux/slub_def.h> +#else +#error "Unknown slab allocator" +#endif + +/* + * Determine size used for the nth kmalloc cache. + * return size or 0 if a kmalloc cache for that + * size does not exist + */ +static __always_inline int kmalloc_size(int n) +{ + if (n > 2) + return 1 << n; + + if (n == 1 && KMALLOC_MIN_SIZE <= 32) + return 96; + + if (n == 2 && KMALLOC_MIN_SIZE <= 64) + return 192; + + return 0; +} +#endif /* !CONFIG_SLOB */ + +/* + * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment. + * Intended for arches that get misalignment faults even for 64 bit integer + * aligned buffers. + */ +#ifndef ARCH_SLAB_MINALIGN +#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long) +#endif +/* + * This is the main placeholder for memcg-related information in kmem caches. + * struct kmem_cache will hold a pointer to it, so the memory cost while + * disabled is 1 pointer. The runtime cost while enabled, gets bigger than it + * would otherwise be if that would be bundled in kmem_cache: we'll need an + * extra pointer chase. But the trade off clearly lays in favor of not + * penalizing non-users. + * + * Both the root cache and the child caches will have it. For the root cache, + * this will hold a dynamically allocated array large enough to hold + * information about the currently limited memcgs in the system. + * + * Child caches will hold extra metadata needed for its operation. Fields are: + * + * @memcg: pointer to the memcg this cache belongs to + * @list: list_head for the list of all caches in this memcg + * @root_cache: pointer to the global, root cache, this cache was derived from + * @dead: set to true after the memcg dies; the cache may still be around. + * @nr_pages: number of pages that belongs to this cache. + * @destroy: worker to be called whenever we are ready, or believe we may be + * ready, to destroy this cache. + */ +struct memcg_cache_params { + bool is_root_cache; + union { + struct kmem_cache *memcg_caches[0]; + struct { + struct mem_cgroup *memcg; + struct list_head list; + struct kmem_cache *root_cache; + bool dead; + atomic_t nr_pages; + struct work_struct destroy; + }; + }; +}; + +int memcg_update_all_caches(int num_memcgs); + +struct seq_file; +int cache_show(struct kmem_cache *s, struct seq_file *m); +void print_slabinfo_header(struct seq_file *m); + +/** + * kmalloc_array - allocate memory for an array. + * @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 *kmalloc_array(size_t n, size_t size, gfp_t flags) +{ + if (size != 0 && n > SIZE_MAX / size) + return NULL; + return __kmalloc(n * size, flags); +} + +/** + * 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 (see kmalloc). + */ +static inline void *kcalloc(size_t n, size_t size, gfp_t flags) +{ + return kmalloc_array(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)) || \ + (defined(CONFIG_SLOB) && 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)) || \ + (defined(CONFIG_SLOB) && 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); +} + +/* + * Determine the size of a slab object + */ +static inline unsigned int kmem_cache_size(struct kmem_cache *s) +{ + return s->object_size; +} + +void __init kmem_cache_init_late(void); + +#endif /* _LINUX_SLAB_H */ |