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>
14 #include <linux/workqueue.h>
18 * Flags to pass to kmem_cache_create().
19 * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
21 #define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
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 */
25 #define SLAB_CACHE_DMA 0x00004000UL /* Use GFP_DMA memory */
26 #define SLAB_STORE_USER 0x00010000UL /* DEBUG: Store the last owner for bug hunting */
27 #define SLAB_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
29 * SLAB_DESTROY_BY_RCU - **WARNING** READ THIS!
31 * This delays freeing the SLAB page by a grace period, it does _NOT_
32 * delay object freeing. This means that if you do kmem_cache_free()
33 * that memory location is free to be reused at any time. Thus it may
34 * be possible to see another object there in the same RCU grace period.
36 * This feature only ensures the memory location backing the object
37 * stays valid, the trick to using this is relying on an independent
38 * object validation pass. Something like:
42 * obj = lockless_lookup(key);
44 * if (!try_get_ref(obj)) // might fail for free objects
47 * if (obj->key != key) { // not the object we expected
54 * See also the comment on struct slab_rcu in mm/slab.c.
56 #define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
57 #define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
58 #define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */
60 /* Flag to prevent checks on free */
61 #ifdef CONFIG_DEBUG_OBJECTS
62 # define SLAB_DEBUG_OBJECTS 0x00400000UL
64 # define SLAB_DEBUG_OBJECTS 0x00000000UL
67 #define SLAB_NOLEAKTRACE 0x00800000UL /* Avoid kmemleak tracing */
69 /* Don't track use of uninitialized memory */
70 #ifdef CONFIG_KMEMCHECK
71 # define SLAB_NOTRACK 0x01000000UL
73 # define SLAB_NOTRACK 0x00000000UL
75 #ifdef CONFIG_FAILSLAB
76 # define SLAB_FAILSLAB 0x02000000UL /* Fault injection mark */
78 # define SLAB_FAILSLAB 0x00000000UL
81 /* The following flags affect the page allocator grouping pages by mobility */
82 #define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
83 #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
85 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
87 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
89 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
90 * Both make kfree a no-op.
92 #define ZERO_SIZE_PTR ((void *)16)
94 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
95 (unsigned long)ZERO_SIZE_PTR)
100 * struct kmem_cache related prototypes
102 void __init
kmem_cache_init(void);
103 int slab_is_available(void);
105 struct kmem_cache
*kmem_cache_create(const char *, size_t, size_t,
109 kmem_cache_create_memcg(struct mem_cgroup
*, const char *, size_t, size_t,
110 unsigned long, void (*)(void *), struct kmem_cache
*);
111 void kmem_cache_destroy(struct kmem_cache
*);
112 int kmem_cache_shrink(struct kmem_cache
*);
113 void kmem_cache_free(struct kmem_cache
*, void *);
116 * Please use this macro to create slab caches. Simply specify the
117 * name of the structure and maybe some flags that are listed above.
119 * The alignment of the struct determines object alignment. If you
120 * f.e. add ____cacheline_aligned_in_smp to the struct declaration
121 * then the objects will be properly aligned in SMP configurations.
123 #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
124 sizeof(struct __struct), __alignof__(struct __struct),\
128 * Common kmalloc functions provided by all allocators
130 void * __must_check
__krealloc(const void *, size_t, gfp_t
);
131 void * __must_check
krealloc(const void *, size_t, gfp_t
);
132 void kfree(const void *);
133 void kzfree(const void *);
134 size_t ksize(const void *);
138 * Common fields provided in kmem_cache by all slab allocators
139 * This struct is either used directly by the allocator (SLOB)
140 * or the allocator must include definitions for all fields
141 * provided in kmem_cache_common in their definition of kmem_cache.
143 * Once we can do anonymous structs (C11 standard) we could put a
144 * anonymous struct definition in these allocators so that the
145 * separate allocations in the kmem_cache structure of SLAB and
146 * SLUB is no longer needed.
149 unsigned int object_size
;/* The original size of the object */
150 unsigned int size
; /* The aligned/padded/added on size */
151 unsigned int align
; /* Alignment as calculated */
152 unsigned long flags
; /* Active flags on the slab */
153 const char *name
; /* Slab name for sysfs */
154 int refcount
; /* Use counter */
155 void (*ctor
)(void *); /* Called on object slot creation */
156 struct list_head list
; /* List of all slab caches on the system */
159 #define KMALLOC_MAX_SIZE (1UL << 30)
161 #include <linux/slob_def.h>
163 #else /* CONFIG_SLOB */
166 * The largest kmalloc size supported by the slab allocators is
167 * 32 megabyte (2^25) or the maximum allocatable page order if that is
170 * WARNING: Its not easy to increase this value since the allocators have
171 * to do various tricks to work around compiler limitations in order to
172 * ensure proper constant folding.
174 #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
175 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
177 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
178 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
183 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
184 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
187 #define KMALLOC_MIN_SIZE 32
189 #define KMALLOC_MIN_SIZE 8
193 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
196 * Figure out which kmalloc slab an allocation of a certain size
200 * 2 = 120 .. 192 bytes
201 * n = 2^(n-1) .. 2^n -1
203 static __always_inline
int kmalloc_index(size_t size
)
208 if (size
<= KMALLOC_MIN_SIZE
)
209 return KMALLOC_SHIFT_LOW
;
211 if (KMALLOC_MIN_SIZE
<= 32 && size
> 64 && size
<= 96)
213 if (KMALLOC_MIN_SIZE
<= 64 && size
> 128 && size
<= 192)
215 if (size
<= 8) return 3;
216 if (size
<= 16) return 4;
217 if (size
<= 32) return 5;
218 if (size
<= 64) return 6;
219 if (size
<= 128) return 7;
220 if (size
<= 256) return 8;
221 if (size
<= 512) return 9;
222 if (size
<= 1024) return 10;
223 if (size
<= 2 * 1024) return 11;
224 if (size
<= 4 * 1024) return 12;
225 if (size
<= 8 * 1024) return 13;
226 if (size
<= 16 * 1024) return 14;
227 if (size
<= 32 * 1024) return 15;
228 if (size
<= 64 * 1024) return 16;
229 if (size
<= 128 * 1024) return 17;
230 if (size
<= 256 * 1024) return 18;
231 if (size
<= 512 * 1024) return 19;
232 if (size
<= 1024 * 1024) return 20;
233 if (size
<= 2 * 1024 * 1024) return 21;
234 if (size
<= 4 * 1024 * 1024) return 22;
235 if (size
<= 8 * 1024 * 1024) return 23;
236 if (size
<= 16 * 1024 * 1024) return 24;
237 if (size
<= 32 * 1024 * 1024) return 25;
238 if (size
<= 64 * 1024 * 1024) return 26;
241 /* Will never be reached. Needed because the compiler may complain */
246 #include <linux/slab_def.h>
247 #elif defined(CONFIG_SLUB)
248 #include <linux/slub_def.h>
250 #error "Unknown slab allocator"
254 * Determine size used for the nth kmalloc cache.
255 * return size or 0 if a kmalloc cache for that
256 * size does not exist
258 static __always_inline
int kmalloc_size(int n
)
263 if (n
== 1 && KMALLOC_MIN_SIZE
<= 32)
266 if (n
== 2 && KMALLOC_MIN_SIZE
<= 64)
271 #endif /* !CONFIG_SLOB */
274 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
275 * alignment larger than the alignment of a 64-bit integer.
276 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
278 #ifdef ARCH_DMA_MINALIGN
279 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
281 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
285 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
286 * Intended for arches that get misalignment faults even for 64 bit integer
289 #ifndef ARCH_SLAB_MINALIGN
290 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
293 * This is the main placeholder for memcg-related information in kmem caches.
294 * struct kmem_cache will hold a pointer to it, so the memory cost while
295 * disabled is 1 pointer. The runtime cost while enabled, gets bigger than it
296 * would otherwise be if that would be bundled in kmem_cache: we'll need an
297 * extra pointer chase. But the trade off clearly lays in favor of not
298 * penalizing non-users.
300 * Both the root cache and the child caches will have it. For the root cache,
301 * this will hold a dynamically allocated array large enough to hold
302 * information about the currently limited memcgs in the system.
304 * Child caches will hold extra metadata needed for its operation. Fields are:
306 * @memcg: pointer to the memcg this cache belongs to
307 * @list: list_head for the list of all caches in this memcg
308 * @root_cache: pointer to the global, root cache, this cache was derived from
309 * @dead: set to true after the memcg dies; the cache may still be around.
310 * @nr_pages: number of pages that belongs to this cache.
311 * @destroy: worker to be called whenever we are ready, or believe we may be
312 * ready, to destroy this cache.
314 struct memcg_cache_params
{
317 struct kmem_cache
*memcg_caches
[0];
319 struct mem_cgroup
*memcg
;
320 struct list_head list
;
321 struct kmem_cache
*root_cache
;
324 struct work_struct destroy
;
329 int memcg_update_all_caches(int num_memcgs
);
332 int cache_show(struct kmem_cache
*s
, struct seq_file
*m
);
333 void print_slabinfo_header(struct seq_file
*m
);
336 * kmalloc_array - allocate memory for an array.
337 * @n: number of elements.
338 * @size: element size.
339 * @flags: the type of memory to allocate.
341 * The @flags argument may be one of:
343 * %GFP_USER - Allocate memory on behalf of user. May sleep.
345 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
347 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
348 * For example, use this inside interrupt handlers.
350 * %GFP_HIGHUSER - Allocate pages from high memory.
352 * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
354 * %GFP_NOFS - Do not make any fs calls while trying to get memory.
356 * %GFP_NOWAIT - Allocation will not sleep.
358 * %GFP_THISNODE - Allocate node-local memory only.
360 * %GFP_DMA - Allocation suitable for DMA.
361 * Should only be used for kmalloc() caches. Otherwise, use a
362 * slab created with SLAB_DMA.
364 * Also it is possible to set different flags by OR'ing
365 * in one or more of the following additional @flags:
367 * %__GFP_COLD - Request cache-cold pages instead of
368 * trying to return cache-warm pages.
370 * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
372 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
373 * (think twice before using).
375 * %__GFP_NORETRY - If memory is not immediately available,
376 * then give up at once.
378 * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
380 * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
382 * There are other flags available as well, but these are not intended
383 * for general use, and so are not documented here. For a full list of
384 * potential flags, always refer to linux/gfp.h.
386 static inline void *kmalloc_array(size_t n
, size_t size
, gfp_t flags
)
388 if (size
!= 0 && n
> SIZE_MAX
/ size
)
390 return __kmalloc(n
* size
, flags
);
394 * kcalloc - allocate memory for an array. The memory is set to zero.
395 * @n: number of elements.
396 * @size: element size.
397 * @flags: the type of memory to allocate (see kmalloc).
399 static inline void *kcalloc(size_t n
, size_t size
, gfp_t flags
)
401 return kmalloc_array(n
, size
, flags
| __GFP_ZERO
);
404 #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
406 * kmalloc_node - allocate memory from a specific node
407 * @size: how many bytes of memory are required.
408 * @flags: the type of memory to allocate (see kcalloc).
409 * @node: node to allocate from.
411 * kmalloc() for non-local nodes, used to allocate from a specific node
412 * if available. Equivalent to kmalloc() in the non-NUMA single-node
415 static inline void *kmalloc_node(size_t size
, gfp_t flags
, int node
)
417 return kmalloc(size
, flags
);
420 static inline void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
422 return __kmalloc(size
, flags
);
425 void *kmem_cache_alloc(struct kmem_cache
*, gfp_t
);
427 static inline void *kmem_cache_alloc_node(struct kmem_cache
*cachep
,
428 gfp_t flags
, int node
)
430 return kmem_cache_alloc(cachep
, flags
);
432 #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
435 * kmalloc_track_caller is a special version of kmalloc that records the
436 * calling function of the routine calling it for slab leak tracking instead
437 * of just the calling function (confusing, eh?).
438 * It's useful when the call to kmalloc comes from a widely-used standard
439 * allocator where we care about the real place the memory allocation
440 * request comes from.
442 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
443 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) || \
444 (defined(CONFIG_SLOB) && defined(CONFIG_TRACING))
445 extern void *__kmalloc_track_caller(size_t, gfp_t
, unsigned long);
446 #define kmalloc_track_caller(size, flags) \
447 __kmalloc_track_caller(size, flags, _RET_IP_)
449 #define kmalloc_track_caller(size, flags) \
450 __kmalloc(size, flags)
451 #endif /* DEBUG_SLAB */
455 * kmalloc_node_track_caller is a special version of kmalloc_node that
456 * records the calling function of the routine calling it for slab leak
457 * tracking instead of just the calling function (confusing, eh?).
458 * It's useful when the call to kmalloc_node comes from a widely-used
459 * standard allocator where we care about the real place the memory
460 * allocation request comes from.
462 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
463 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) || \
464 (defined(CONFIG_SLOB) && defined(CONFIG_TRACING))
465 extern void *__kmalloc_node_track_caller(size_t, gfp_t
, int, unsigned long);
466 #define kmalloc_node_track_caller(size, flags, node) \
467 __kmalloc_node_track_caller(size, flags, node, \
470 #define kmalloc_node_track_caller(size, flags, node) \
471 __kmalloc_node(size, flags, node)
474 #else /* CONFIG_NUMA */
476 #define kmalloc_node_track_caller(size, flags, node) \
477 kmalloc_track_caller(size, flags)
479 #endif /* CONFIG_NUMA */
484 static inline void *kmem_cache_zalloc(struct kmem_cache
*k
, gfp_t flags
)
486 return kmem_cache_alloc(k
, flags
| __GFP_ZERO
);
490 * kzalloc - allocate memory. The memory is set to zero.
491 * @size: how many bytes of memory are required.
492 * @flags: the type of memory to allocate (see kmalloc).
494 static inline void *kzalloc(size_t size
, gfp_t flags
)
496 return kmalloc(size
, flags
| __GFP_ZERO
);
500 * kzalloc_node - allocate zeroed memory from a particular memory node.
501 * @size: how many bytes of memory are required.
502 * @flags: the type of memory to allocate (see kmalloc).
503 * @node: memory node from which to allocate
505 static inline void *kzalloc_node(size_t size
, gfp_t flags
, int node
)
507 return kmalloc_node(size
, flags
| __GFP_ZERO
, node
);
511 * Determine the size of a slab object
513 static inline unsigned int kmem_cache_size(struct kmem_cache
*s
)
515 return s
->object_size
;
518 void __init
kmem_cache_init_late(void);
520 #endif /* _LINUX_SLAB_H */
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