1/* 2 * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk). 3 * 4 * (C) SGI 2006, Christoph Lameter 5 * Cleaned up and restructured to ease the addition of alternative 6 * implementations of SLAB allocators. 7 */ 8 9#ifndef _LINUX_SLAB_H 10#define _LINUX_SLAB_H 11 12#include <linux/gfp.h> 13#include <linux/types.h> 14#include <linux/workqueue.h> 15 16 17/* 18 * Flags to pass to kmem_cache_create(). 19 * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set. 20 */ 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 */ 28/* 29 * SLAB_DESTROY_BY_RCU - **WARNING** READ THIS! 30 * 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. 35 * 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: 39 * 40 * rcu_read_lock() 41 * again: 42 * obj = lockless_lookup(key); 43 * if (obj) { 44 * if (!try_get_ref(obj)) // might fail for free objects 45 * goto again; 46 * 47 * if (obj->key != key) { // not the object we expected 48 * put_ref(obj); 49 * goto again; 50 * } 51 * } 52 * rcu_read_unlock(); 53 * 54 * See also the comment on struct slab_rcu in mm/slab.c. 55 */ 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 */ 59 60/* Flag to prevent checks on free */ 61#ifdef CONFIG_DEBUG_OBJECTS 62# define SLAB_DEBUG_OBJECTS 0x00400000UL 63#else 64# define SLAB_DEBUG_OBJECTS 0x00000000UL 65#endif 66 67#define SLAB_NOLEAKTRACE 0x00800000UL /* Avoid kmemleak tracing */ 68 69/* Don't track use of uninitialized memory */ 70#ifdef CONFIG_KMEMCHECK 71# define SLAB_NOTRACK 0x01000000UL 72#else 73# define SLAB_NOTRACK 0x00000000UL 74#endif 75#ifdef CONFIG_FAILSLAB 76# define SLAB_FAILSLAB 0x02000000UL /* Fault injection mark */ 77#else 78# define SLAB_FAILSLAB 0x00000000UL 79#endif 80 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 */ 84/* 85 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests. 86 * 87 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault. 88 * 89 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can. 90 * Both make kfree a no-op. 91 */ 92#define ZERO_SIZE_PTR ((void *)16) 93 94#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \ 95 (unsigned long)ZERO_SIZE_PTR) 96 97 98struct mem_cgroup; 99/* 100 * struct kmem_cache related prototypes 101 */ 102void __init kmem_cache_init(void); 103int slab_is_available(void); 104 105struct kmem_cache *kmem_cache_create(const char *, size_t, size_t, 106 unsigned long, 107 void (*)(void *)); 108struct kmem_cache * 109kmem_cache_create_memcg(struct mem_cgroup *, const char *, size_t, size_t, 110 unsigned long, void (*)(void *), struct kmem_cache *); 111void kmem_cache_destroy(struct kmem_cache *); 112int kmem_cache_shrink(struct kmem_cache *); 113void kmem_cache_free(struct kmem_cache *, void *); 114 115/* 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. 118 * 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. 122 */ 123#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\ 124 sizeof(struct __struct), __alignof__(struct __struct),\ 125 (__flags), NULL) 126 127/* 128 * Common kmalloc functions provided by all allocators 129 */ 130void * __must_check __krealloc(const void *, size_t, gfp_t); 131void * __must_check krealloc(const void *, size_t, gfp_t); 132void kfree(const void *); 133void kzfree(const void *); 134size_t ksize(const void *); 135 136/* 137 * Some archs want to perform DMA into kmalloc caches and need a guaranteed 138 * alignment larger than the alignment of a 64-bit integer. 139 * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that. 140 */ 141#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8 142#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN 143#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN 144#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN) 145#else 146#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) 147#endif 148 149#ifdef CONFIG_SLOB 150/* 151 * Common fields provided in kmem_cache by all slab allocators 152 * This struct is either used directly by the allocator (SLOB) 153 * or the allocator must include definitions for all fields 154 * provided in kmem_cache_common in their definition of kmem_cache. 155 * 156 * Once we can do anonymous structs (C11 standard) we could put a 157 * anonymous struct definition in these allocators so that the 158 * separate allocations in the kmem_cache structure of SLAB and 159 * SLUB is no longer needed. 160 */ 161struct kmem_cache { 162 unsigned int object_size;/* The original size of the object */ 163 unsigned int size; /* The aligned/padded/added on size */ 164 unsigned int align; /* Alignment as calculated */ 165 unsigned long flags; /* Active flags on the slab */ 166 const char *name; /* Slab name for sysfs */ 167 int refcount; /* Use counter */ 168 void (*ctor)(void *); /* Called on object slot creation */ 169 struct list_head list; /* List of all slab caches on the system */ 170}; 171 172#endif /* CONFIG_SLOB */ 173 174/* 175 * Kmalloc array related definitions 176 */ 177 178#ifdef CONFIG_SLAB 179/* 180 * The largest kmalloc size supported by the SLAB allocators is 181 * 32 megabyte (2^25) or the maximum allocatable page order if that is 182 * less than 32 MB. 183 * 184 * WARNING: Its not easy to increase this value since the allocators have 185 * to do various tricks to work around compiler limitations in order to 186 * ensure proper constant folding. 187 */ 188#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \ 189 (MAX_ORDER + PAGE_SHIFT - 1) : 25) 190#define KMALLOC_SHIFT_MAX KMALLOC_SHIFT_HIGH 191#ifndef KMALLOC_SHIFT_LOW 192#define KMALLOC_SHIFT_LOW 5 193#endif 194#endif 195 196#ifdef CONFIG_SLUB 197/* 198 * SLUB allocates up to order 2 pages directly and otherwise 199 * passes the request to the page allocator. 200 */ 201#define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1) 202#define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT) 203#ifndef KMALLOC_SHIFT_LOW 204#define KMALLOC_SHIFT_LOW 3 205#endif 206#endif 207 208#ifdef CONFIG_SLOB 209/* 210 * SLOB passes all page size and larger requests to the page allocator. 211 * No kmalloc array is necessary since objects of different sizes can 212 * be allocated from the same page. 213 */ 214#define KMALLOC_SHIFT_MAX 30 215#define KMALLOC_SHIFT_HIGH PAGE_SHIFT 216#ifndef KMALLOC_SHIFT_LOW 217#define KMALLOC_SHIFT_LOW 3 218#endif 219#endif 220 221/* Maximum allocatable size */ 222#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX) 223/* Maximum size for which we actually use a slab cache */ 224#define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH) 225/* Maximum order allocatable via the slab allocagtor */ 226#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT) 227 228/* 229 * Kmalloc subsystem. 230 */ 231#ifndef KMALLOC_MIN_SIZE 232#define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW) 233#endif 234 235#ifndef CONFIG_SLOB 236extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1]; 237#ifdef CONFIG_ZONE_DMA 238extern struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1]; 239#endif 240 241/* 242 * Figure out which kmalloc slab an allocation of a certain size 243 * belongs to. 244 * 0 = zero alloc 245 * 1 = 65 .. 96 bytes 246 * 2 = 120 .. 192 bytes 247 * n = 2^(n-1) .. 2^n -1 248 */ 249static __always_inline int kmalloc_index(size_t size) 250{ 251 if (!size) 252 return 0; 253 254 if (size <= KMALLOC_MIN_SIZE) 255 return KMALLOC_SHIFT_LOW; 256 257 if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96) 258 return 1; 259 if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192) 260 return 2; 261 if (size <= 8) return 3; 262 if (size <= 16) return 4; 263 if (size <= 32) return 5; 264 if (size <= 64) return 6; 265 if (size <= 128) return 7; 266 if (size <= 256) return 8; 267 if (size <= 512) return 9; 268 if (size <= 1024) return 10; 269 if (size <= 2 * 1024) return 11; 270 if (size <= 4 * 1024) return 12; 271 if (size <= 8 * 1024) return 13; 272 if (size <= 16 * 1024) return 14; 273 if (size <= 32 * 1024) return 15; 274 if (size <= 64 * 1024) return 16; 275 if (size <= 128 * 1024) return 17; 276 if (size <= 256 * 1024) return 18; 277 if (size <= 512 * 1024) return 19; 278 if (size <= 1024 * 1024) return 20; 279 if (size <= 2 * 1024 * 1024) return 21; 280 if (size <= 4 * 1024 * 1024) return 22; 281 if (size <= 8 * 1024 * 1024) return 23; 282 if (size <= 16 * 1024 * 1024) return 24; 283 if (size <= 32 * 1024 * 1024) return 25; 284 if (size <= 64 * 1024 * 1024) return 26; 285 BUG(); 286 287 /* Will never be reached. Needed because the compiler may complain */ 288 return -1; 289} 290#endif /* !CONFIG_SLOB */ 291 292#ifdef CONFIG_SLAB 293#include <linux/slab_def.h> 294#endif 295 296#ifdef CONFIG_SLUB 297#include <linux/slub_def.h> 298#endif 299 300#ifdef CONFIG_SLOB 301#include <linux/slob_def.h> 302#endif 303 304/* 305 * Determine size used for the nth kmalloc cache. 306 * return size or 0 if a kmalloc cache for that 307 * size does not exist 308 */ 309static __always_inline int kmalloc_size(int n) 310{ 311#ifndef CONFIG_SLOB 312 if (n > 2) 313 return 1 << n; 314 315 if (n == 1 && KMALLOC_MIN_SIZE <= 32) 316 return 96; 317 318 if (n == 2 && KMALLOC_MIN_SIZE <= 64) 319 return 192; 320#endif 321 return 0; 322} 323 324/* 325 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment. 326 * Intended for arches that get misalignment faults even for 64 bit integer 327 * aligned buffers. 328 */ 329#ifndef ARCH_SLAB_MINALIGN 330#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long) 331#endif 332/* 333 * This is the main placeholder for memcg-related information in kmem caches. 334 * struct kmem_cache will hold a pointer to it, so the memory cost while 335 * disabled is 1 pointer. The runtime cost while enabled, gets bigger than it 336 * would otherwise be if that would be bundled in kmem_cache: we'll need an 337 * extra pointer chase. But the trade off clearly lays in favor of not 338 * penalizing non-users. 339 * 340 * Both the root cache and the child caches will have it. For the root cache, 341 * this will hold a dynamically allocated array large enough to hold 342 * information about the currently limited memcgs in the system. 343 * 344 * Child caches will hold extra metadata needed for its operation. Fields are: 345 * 346 * @memcg: pointer to the memcg this cache belongs to 347 * @list: list_head for the list of all caches in this memcg 348 * @root_cache: pointer to the global, root cache, this cache was derived from 349 * @dead: set to true after the memcg dies; the cache may still be around. 350 * @nr_pages: number of pages that belongs to this cache. 351 * @destroy: worker to be called whenever we are ready, or believe we may be 352 * ready, to destroy this cache. 353 */ 354struct memcg_cache_params { 355 bool is_root_cache; 356 union { 357 struct kmem_cache *memcg_caches[0]; 358 struct { 359 struct mem_cgroup *memcg; 360 struct list_head list; 361 struct kmem_cache *root_cache; 362 bool dead; 363 atomic_t nr_pages; 364 struct work_struct destroy; 365 }; 366 }; 367}; 368 369int memcg_update_all_caches(int num_memcgs); 370 371struct seq_file; 372int cache_show(struct kmem_cache *s, struct seq_file *m); 373void print_slabinfo_header(struct seq_file *m); 374 375/** 376 * kmalloc - allocate memory 377 * @size: how many bytes of memory are required. 378 * @flags: the type of memory to allocate. 379 * 380 * The @flags argument may be one of: 381 * 382 * %GFP_USER - Allocate memory on behalf of user. May sleep. 383 * 384 * %GFP_KERNEL - Allocate normal kernel ram. May sleep. 385 * 386 * %GFP_ATOMIC - Allocation will not sleep. May use emergency pools. 387 * For example, use this inside interrupt handlers. 388 * 389 * %GFP_HIGHUSER - Allocate pages from high memory. 390 * 391 * %GFP_NOIO - Do not do any I/O at all while trying to get memory. 392 * 393 * %GFP_NOFS - Do not make any fs calls while trying to get memory. 394 * 395 * %GFP_NOWAIT - Allocation will not sleep. 396 * 397 * %GFP_THISNODE - Allocate node-local memory only. 398 * 399 * %GFP_DMA - Allocation suitable for DMA. 400 * Should only be used for kmalloc() caches. Otherwise, use a 401 * slab created with SLAB_DMA. 402 * 403 * Also it is possible to set different flags by OR'ing 404 * in one or more of the following additional @flags: 405 * 406 * %__GFP_COLD - Request cache-cold pages instead of 407 * trying to return cache-warm pages. 408 * 409 * %__GFP_HIGH - This allocation has high priority and may use emergency pools. 410 * 411 * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail 412 * (think twice before using). 413 * 414 * %__GFP_NORETRY - If memory is not immediately available, 415 * then give up at once. 416 * 417 * %__GFP_NOWARN - If allocation fails, don't issue any warnings. 418 * 419 * %__GFP_REPEAT - If allocation fails initially, try once more before failing. 420 * 421 * There are other flags available as well, but these are not intended 422 * for general use, and so are not documented here. For a full list of 423 * potential flags, always refer to linux/gfp.h. 424 * 425 * kmalloc is the normal method of allocating memory 426 * in the kernel. 427 */ 428static __always_inline void *kmalloc(size_t size, gfp_t flags); 429 430/** 431 * kmalloc_array - allocate memory for an array. 432 * @n: number of elements. 433 * @size: element size. 434 * @flags: the type of memory to allocate (see kmalloc). 435 */ 436static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags) 437{ 438 if (size != 0 && n > SIZE_MAX / size) 439 return NULL; 440 return __kmalloc(n * size, flags); 441} 442 443/** 444 * kcalloc - allocate memory for an array. The memory is set to zero. 445 * @n: number of elements. 446 * @size: element size. 447 * @flags: the type of memory to allocate (see kmalloc). 448 */ 449static inline void *kcalloc(size_t n, size_t size, gfp_t flags) 450{ 451 return kmalloc_array(n, size, flags | __GFP_ZERO); 452} 453 454#if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB) 455/** 456 * kmalloc_node - allocate memory from a specific node 457 * @size: how many bytes of memory are required. 458 * @flags: the type of memory to allocate (see kmalloc). 459 * @node: node to allocate from. 460 * 461 * kmalloc() for non-local nodes, used to allocate from a specific node 462 * if available. Equivalent to kmalloc() in the non-NUMA single-node 463 * case. 464 */ 465static inline void *kmalloc_node(size_t size, gfp_t flags, int node) 466{ 467 return kmalloc(size, flags); 468} 469 470static inline void *__kmalloc_node(size_t size, gfp_t flags, int node) 471{ 472 return __kmalloc(size, flags); 473} 474 475void *kmem_cache_alloc(struct kmem_cache *, gfp_t); 476 477static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep, 478 gfp_t flags, int node) 479{ 480 return kmem_cache_alloc(cachep, flags); 481} 482#endif /* !CONFIG_NUMA && !CONFIG_SLOB */ 483 484/* 485 * kmalloc_track_caller is a special version of kmalloc that records the 486 * calling function of the routine calling it for slab leak tracking instead 487 * of just the calling function (confusing, eh?). 488 * It's useful when the call to kmalloc comes from a widely-used standard 489 * allocator where we care about the real place the memory allocation 490 * request comes from. 491 */ 492#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \ 493 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) || \ 494 (defined(CONFIG_SLOB) && defined(CONFIG_TRACING)) 495extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long); 496#define kmalloc_track_caller(size, flags) \ 497 __kmalloc_track_caller(size, flags, _RET_IP_) 498#else 499#define kmalloc_track_caller(size, flags) \ 500 __kmalloc(size, flags) 501#endif /* DEBUG_SLAB */ 502 503#ifdef CONFIG_NUMA 504/* 505 * kmalloc_node_track_caller is a special version of kmalloc_node that 506 * records the calling function of the routine calling it for slab leak 507 * tracking instead of just the calling function (confusing, eh?). 508 * It's useful when the call to kmalloc_node comes from a widely-used 509 * standard allocator where we care about the real place the memory 510 * allocation request comes from. 511 */ 512#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \ 513 (defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) || \ 514 (defined(CONFIG_SLOB) && defined(CONFIG_TRACING)) 515extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long); 516#define kmalloc_node_track_caller(size, flags, node) \ 517 __kmalloc_node_track_caller(size, flags, node, \ 518 _RET_IP_) 519#else 520#define kmalloc_node_track_caller(size, flags, node) \ 521 __kmalloc_node(size, flags, node) 522#endif 523 524#else /* CONFIG_NUMA */ 525 526#define kmalloc_node_track_caller(size, flags, node) \ 527 kmalloc_track_caller(size, flags) 528 529#endif /* CONFIG_NUMA */ 530 531/* 532 * Shortcuts 533 */ 534static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags) 535{ 536 return kmem_cache_alloc(k, flags | __GFP_ZERO); 537} 538 539/** 540 * kzalloc - allocate memory. The memory is set to zero. 541 * @size: how many bytes of memory are required. 542 * @flags: the type of memory to allocate (see kmalloc). 543 */ 544static inline void *kzalloc(size_t size, gfp_t flags) 545{ 546 return kmalloc(size, flags | __GFP_ZERO); 547} 548 549/** 550 * kzalloc_node - allocate zeroed memory from a particular memory node. 551 * @size: how many bytes of memory are required. 552 * @flags: the type of memory to allocate (see kmalloc). 553 * @node: memory node from which to allocate 554 */ 555static inline void *kzalloc_node(size_t size, gfp_t flags, int node) 556{ 557 return kmalloc_node(size, flags | __GFP_ZERO, node); 558} 559 560/* 561 * Determine the size of a slab object 562 */ 563static inline unsigned int kmem_cache_size(struct kmem_cache *s) 564{ 565 return s->object_size; 566} 567 568void __init kmem_cache_init_late(void); 569 570#endif /* _LINUX_SLAB_H */ 571