mm/slab.h

   1 #ifndef MM_SLAB_H
   2 #define MM_SLAB_H
   3 /*
   4  * Internal slab definitions
   5  */
   6
   7 #ifdef CONFIG_SLOB
   8 /*
   9  * Common fields provided in kmem_cache by all slab allocators
  10  * This struct is either used directly by the allocator (SLOB)
  11  * or the allocator must include definitions for all fields
  12  * provided in kmem_cache_common in their definition of kmem_cache.
  13  *
  14  * Once we can do anonymous structs (C11 standard) we could put a
  15  * anonymous struct definition in these allocators so that the
  16  * separate allocations in the kmem_cache structure of SLAB and
  17  * SLUB is no longer needed.
  18  */
  19 struct kmem_cache {
  20         unsigned int object_size;/* The original size of the object */
  21         unsigned int size;      /* The aligned/padded/added on size  */
  22         unsigned int align;     /* Alignment as calculated */
  23         unsigned long flags;    /* Active flags on the slab */
  24         const char *name;       /* Slab name for sysfs */
  25         int refcount;           /* Use counter */
  26         void (*ctor)(void *);   /* Called on object slot creation */
  27         struct list_head list;  /* List of all slab caches on the system */
  28 };
  29
  30 #endif /* CONFIG_SLOB */
  31
  32 #ifdef CONFIG_SLAB
  33 #include <linux/slab_def.h>
  34 #endif
  35
  36 #ifdef CONFIG_SLUB
  37 #include <linux/slub_def.h>
  38 #endif
  39
  40 #include <linux/memcontrol.h>
  41 #include <linux/fault-inject.h>
  42 #include <linux/kmemcheck.h>
  43 #include <linux/kasan.h>
  44 #include <linux/kmemleak.h>
  45 #include <linux/random.h>
  46
  47 /*
  48  * State of the slab allocator.
  49  *
  50  * This is used to describe the states of the allocator during bootup.
  51  * Allocators use this to gradually bootstrap themselves. Most allocators
  52  * have the problem that the structures used for managing slab caches are
  53  * allocated from slab caches themselves.
  54  */
  55 enum slab_state {
  56         DOWN,                   /* No slab functionality yet */
  57         PARTIAL,                /* SLUB: kmem_cache_node available */
  58         PARTIAL_NODE,           /* SLAB: kmalloc size for node struct available */
  59         UP,                     /* Slab caches usable but not all extras yet */
  60         FULL                    /* Everything is working */
  61 };
  62
  63 extern enum slab_state slab_state;
  64
  65 /* The slab cache mutex protects the management structures during changes */
  66 extern struct mutex slab_mutex;
  67
  68 /* The list of all slab caches on the system */
  69 extern struct list_head slab_caches;
  70
  71 /* The slab cache that manages slab cache information */
  72 extern struct kmem_cache *kmem_cache;
  73
  74 /* A table of kmalloc cache names and sizes */
  75 extern const struct kmalloc_info_struct {
  76         const char *name;
  77         unsigned long size;
  78 } kmalloc_info[];
  79
  80 unsigned long calculate_alignment(unsigned long flags,
  81                 unsigned long align, unsigned long size);
  82
  83 #ifndef CONFIG_SLOB
  84 /* Kmalloc array related functions */
  85 void setup_kmalloc_cache_index_table(void);
  86 void create_kmalloc_caches(unsigned long);
  87
  88 /* Find the kmalloc slab corresponding for a certain size */
  89 struct kmem_cache *kmalloc_slab(size_t, gfp_t);
  90 #endif
  91
  92
  93 /* Functions provided by the slab allocators */
  94 extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
  95
  96 extern struct kmem_cache *create_kmalloc_cache(const char *name, size_t size,
  97                         unsigned long flags);
  98 extern void create_boot_cache(struct kmem_cache *, const char *name,
  99                         size_t size, unsigned long flags);
 100
 101 int slab_unmergeable(struct kmem_cache *s);
 102 struct kmem_cache *find_mergeable(size_t size, size_t align,
 103                 unsigned long flags, const char *name, void (*ctor)(void *));
 104 #ifndef CONFIG_SLOB
 105 struct kmem_cache *
 106 __kmem_cache_alias(const char *name, size_t size, size_t align,
 107                    unsigned long flags, void (*ctor)(void *));
 108
 109 unsigned long kmem_cache_flags(unsigned long object_size,
 110         unsigned long flags, const char *name,
 111         void (*ctor)(void *));
 112 #else
 113 static inline struct kmem_cache *
 114 __kmem_cache_alias(const char *name, size_t size, size_t align,
 115                    unsigned long flags, void (*ctor)(void *))
 116 { return NULL; }
 117
 118 static inline unsigned long kmem_cache_flags(unsigned long object_size,
 119         unsigned long flags, const char *name,
 120         void (*ctor)(void *))
 121 {
 122         return flags;
 123 }
 124 #endif
 125
 126
 127 /* Legal flag mask for kmem_cache_create(), for various configurations */
 128 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
 129                          SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS )
 130
 131 #if defined(CONFIG_DEBUG_SLAB)
 132 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 133 #elif defined(CONFIG_SLUB_DEBUG)
 134 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
 135                           SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
 136 #else
 137 #define SLAB_DEBUG_FLAGS (0)
 138 #endif
 139
 140 #if defined(CONFIG_SLAB)
 141 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
 142                           SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
 143                           SLAB_NOTRACK | SLAB_ACCOUNT)
 144 #elif defined(CONFIG_SLUB)
 145 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
 146                           SLAB_TEMPORARY | SLAB_NOTRACK | SLAB_ACCOUNT)
 147 #else
 148 #define SLAB_CACHE_FLAGS (0)
 149 #endif
 150
 151 /* Common flags available with current configuration */
 152 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
 153
 154 /* Common flags permitted for kmem_cache_create */
 155 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
 156                               SLAB_RED_ZONE | \
 157                               SLAB_POISON | \
 158                               SLAB_STORE_USER | \
 159                               SLAB_TRACE | \
 160                               SLAB_CONSISTENCY_CHECKS | \
 161                               SLAB_MEM_SPREAD | \
 162                               SLAB_NOLEAKTRACE | \
 163                               SLAB_RECLAIM_ACCOUNT | \
 164                               SLAB_TEMPORARY | \
 165                               SLAB_NOTRACK | \
 166                               SLAB_ACCOUNT)
 167
 168 int __kmem_cache_shutdown(struct kmem_cache *);
 169 void __kmem_cache_release(struct kmem_cache *);
 170 int __kmem_cache_shrink(struct kmem_cache *, bool);
 171 void slab_kmem_cache_release(struct kmem_cache *);
 172
 173 struct seq_file;
 174 struct file;
 175
 176 struct slabinfo {
 177         unsigned long active_objs;
 178         unsigned long num_objs;
 179         unsigned long active_slabs;
 180         unsigned long num_slabs;
 181         unsigned long shared_avail;
 182         unsigned int limit;
 183         unsigned int batchcount;
 184         unsigned int shared;
 185         unsigned int objects_per_slab;
 186         unsigned int cache_order;
 187 };
 188
 189 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
 190 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
 191 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 192                        size_t count, loff_t *ppos);
 193
 194 /*
 195  * Generic implementation of bulk operations
 196  * These are useful for situations in which the allocator cannot
 197  * perform optimizations. In that case segments of the object listed
 198  * may be allocated or freed using these operations.
 199  */
 200 void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
 201 int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
 202
 203 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
 204
 205 /* List of all root caches. */
 206 extern struct list_head         slab_root_caches;
 207 #define root_caches_node        memcg_params.__root_caches_node
 208
 209 /*
 210  * Iterate over all memcg caches of the given root cache. The caller must hold
 211  * slab_mutex.
 212  */
 213 #define for_each_memcg_cache(iter, root) \
 214         list_for_each_entry(iter, &(root)->memcg_params.children, \
 215                             memcg_params.children_node)
 216
 217 static inline bool is_root_cache(struct kmem_cache *s)
 218 {
 219         return !s->memcg_params.root_cache;
 220 }
 221
 222 static inline bool slab_equal_or_root(struct kmem_cache *s,
 223                                       struct kmem_cache *p)
 224 {
 225         return p == s || p == s->memcg_params.root_cache;
 226 }
 227
 228 /*
 229  * We use suffixes to the name in memcg because we can't have caches
 230  * created in the system with the same name. But when we print them
 231  * locally, better refer to them with the base name
 232  */
 233 static inline const char *cache_name(struct kmem_cache *s)
 234 {
 235         if (!is_root_cache(s))
 236                 s = s->memcg_params.root_cache;
 237         return s->name;
 238 }
 239
 240 /*
 241  * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
 242  * That said the caller must assure the memcg's cache won't go away by either
 243  * taking a css reference to the owner cgroup, or holding the slab_mutex.
 244  */
 245 static inline struct kmem_cache *
 246 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 247 {
 248         struct kmem_cache *cachep;
 249         struct memcg_cache_array *arr;
 250
 251         rcu_read_lock();
 252         arr = rcu_dereference(s->memcg_params.memcg_caches);
 253
 254         /*
 255          * Make sure we will access the up-to-date value. The code updating
 256          * memcg_caches issues a write barrier to match this (see
 257          * memcg_create_kmem_cache()).
 258          */
 259         cachep = lockless_dereference(arr->entries[idx]);
 260         rcu_read_unlock();
 261
 262         return cachep;
 263 }
 264
 265 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 266 {
 267         if (is_root_cache(s))
 268                 return s;
 269         return s->memcg_params.root_cache;
 270 }
 271
 272 static __always_inline int memcg_charge_slab(struct page *page,
 273                                              gfp_t gfp, int order,
 274                                              struct kmem_cache *s)
 275 {
 276         int ret;
 277
 278         if (!memcg_kmem_enabled())
 279                 return 0;
 280         if (is_root_cache(s))
 281                 return 0;
 282
 283         ret = memcg_kmem_charge_memcg(page, gfp, order, s->memcg_params.memcg);
 284         if (ret)
 285                 return ret;
 286
 287         memcg_kmem_update_page_stat(page,
 288                         (s->flags & SLAB_RECLAIM_ACCOUNT) ?
 289                         MEMCG_SLAB_RECLAIMABLE : MEMCG_SLAB_UNRECLAIMABLE,
 290                         1 << order);
 291         return 0;
 292 }
 293
 294 static __always_inline void memcg_uncharge_slab(struct page *page, int order,
 295                                                 struct kmem_cache *s)
 296 {
 297         if (!memcg_kmem_enabled())
 298                 return;
 299
 300         memcg_kmem_update_page_stat(page,
 301                         (s->flags & SLAB_RECLAIM_ACCOUNT) ?
 302                         MEMCG_SLAB_RECLAIMABLE : MEMCG_SLAB_UNRECLAIMABLE,
 303                         -(1 << order));
 304         memcg_kmem_uncharge(page, order);
 305 }
 306
 307 extern void slab_init_memcg_params(struct kmem_cache *);
 308 extern void memcg_link_cache(struct kmem_cache *s);
 309
 310 #else /* CONFIG_MEMCG && !CONFIG_SLOB */
 311
 312 /* If !memcg, all caches are root. */
 313 #define slab_root_caches        slab_caches
 314 #define root_caches_node        list
 315
 316 #define for_each_memcg_cache(iter, root) \
 317         for ((void)(iter), (void)(root); 0; )
 318
 319 static inline bool is_root_cache(struct kmem_cache *s)
 320 {
 321         return true;
 322 }
 323
 324 static inline bool slab_equal_or_root(struct kmem_cache *s,
 325                                       struct kmem_cache *p)
 326 {
 327         return true;
 328 }
 329
 330 static inline const char *cache_name(struct kmem_cache *s)
 331 {
 332         return s->name;
 333 }
 334
 335 static inline struct kmem_cache *
 336 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 337 {
 338         return NULL;
 339 }
 340
 341 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 342 {
 343         return s;
 344 }
 345
 346 static inline int memcg_charge_slab(struct page *page, gfp_t gfp, int order,
 347                                     struct kmem_cache *s)
 348 {
 349         return 0;
 350 }
 351
 352 static inline void memcg_uncharge_slab(struct page *page, int order,
 353                                        struct kmem_cache *s)
 354 {
 355 }
 356
 357 static inline void slab_init_memcg_params(struct kmem_cache *s)
 358 {
 359 }
 360
 361 static inline void memcg_link_cache(struct kmem_cache *s)
 362 {
 363 }
 364
 365 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */
 366
 367 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 368 {
 369         struct kmem_cache *cachep;
 370         struct page *page;
 371
 372         /*
 373          * When kmemcg is not being used, both assignments should return the
 374          * same value. but we don't want to pay the assignment price in that
 375          * case. If it is not compiled in, the compiler should be smart enough
 376          * to not do even the assignment. In that case, slab_equal_or_root
 377          * will also be a constant.
 378          */
 379         if (!memcg_kmem_enabled() &&
 380             !unlikely(s->flags & SLAB_CONSISTENCY_CHECKS))
 381                 return s;
 382
 383         page = virt_to_head_page(x);
 384         cachep = page->slab_cache;
 385         if (slab_equal_or_root(cachep, s))
 386                 return cachep;
 387
 388         pr_err("%s: Wrong slab cache. %s but object is from %s\n",
 389                __func__, s->name, cachep->name);
 390         WARN_ON_ONCE(1);
 391         return s;
 392 }
 393
 394 static inline size_t slab_ksize(const struct kmem_cache *s)
 395 {
 396 #ifndef CONFIG_SLUB
 397         return s->object_size;
 398
 399 #else /* CONFIG_SLUB */
 400 # ifdef CONFIG_SLUB_DEBUG
 401         /*
 402          * Debugging requires use of the padding between object
 403          * and whatever may come after it.
 404          */
 405         if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
 406                 return s->object_size;
 407 # endif
 408         if (s->flags & SLAB_KASAN)
 409                 return s->object_size;
 410         /*
 411          * If we have the need to store the freelist pointer
 412          * back there or track user information then we can
 413          * only use the space before that information.
 414          */
 415         if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
 416                 return s->inuse;
 417         /*
 418          * Else we can use all the padding etc for the allocation
 419          */
 420         return s->size;
 421 #endif
 422 }
 423
 424 static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
 425                                                      gfp_t flags)
 426 {
 427         flags &= gfp_allowed_mask;
 428         lockdep_trace_alloc(flags);
 429         might_sleep_if(gfpflags_allow_blocking(flags));
 430
 431         if (should_failslab(s, flags))
 432                 return NULL;
 433
 434         if (memcg_kmem_enabled() &&
 435             ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
 436                 return memcg_kmem_get_cache(s);
 437
 438         return s;
 439 }
 440
 441 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
 442                                         size_t size, void **p)
 443 {
 444         size_t i;
 445
 446         flags &= gfp_allowed_mask;
 447         for (i = 0; i < size; i++) {
 448                 void *object = p[i];
 449
 450                 kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
 451                 kmemleak_alloc_recursive(object, s->object_size, 1,
 452                                          s->flags, flags);
 453                 kasan_slab_alloc(s, object, flags);
 454         }
 455
 456         if (memcg_kmem_enabled())
 457                 memcg_kmem_put_cache(s);
 458 }
 459
 460 #ifndef CONFIG_SLOB
 461 /*
 462  * The slab lists for all objects.
 463  */
 464 struct kmem_cache_node {
 465         spinlock_t list_lock;
 466
 467 #ifdef CONFIG_SLAB
 468         struct list_head slabs_partial; /* partial list first, better asm code */
 469         struct list_head slabs_full;
 470         struct list_head slabs_free;
 471         unsigned long total_slabs;      /* length of all slab lists */
 472         unsigned long free_slabs;       /* length of free slab list only */
 473         unsigned long free_objects;
 474         unsigned int free_limit;
 475         unsigned int colour_next;       /* Per-node cache coloring */
 476         struct array_cache *shared;     /* shared per node */
 477         struct alien_cache **alien;     /* on other nodes */
 478         unsigned long next_reap;        /* updated without locking */
 479         int free_touched;               /* updated without locking */
 480 #endif
 481
 482 #ifdef CONFIG_SLUB
 483         unsigned long nr_partial;
 484         struct list_head partial;
 485 #ifdef CONFIG_SLUB_DEBUG
 486         atomic_long_t nr_slabs;
 487         atomic_long_t total_objects;
 488         struct list_head full;
 489 #endif
 490 #endif
 491
 492 };
 493
 494 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 495 {
 496         return s->node[node];
 497 }
 498
 499 /*
 500  * Iterator over all nodes. The body will be executed for each node that has
 501  * a kmem_cache_node structure allocated (which is true for all online nodes)
 502  */
 503 #define for_each_kmem_cache_node(__s, __node, __n) \
 504         for (__node = 0; __node < nr_node_ids; __node++) \
 505                  if ((__n = get_node(__s, __node)))
 506
 507 #endif
 508
 509 void *slab_start(struct seq_file *m, loff_t *pos);
 510 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 511 void slab_stop(struct seq_file *m, void *p);
 512 void *memcg_slab_start(struct seq_file *m, loff_t *pos);
 513 void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos);
 514 void memcg_slab_stop(struct seq_file *m, void *p);
 515 int memcg_slab_show(struct seq_file *m, void *p);
 516
 517 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
 518
 519 #ifdef CONFIG_SLAB_FREELIST_RANDOM
 520 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
 521                         gfp_t gfp);
 522 void cache_random_seq_destroy(struct kmem_cache *cachep);
 523 #else
 524 static inline int cache_random_seq_create(struct kmem_cache *cachep,
 525                                         unsigned int count, gfp_t gfp)
 526 {
 527         return 0;
 528 }
 529 static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
 530 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
 531
 532 #endif /* MM_SLAB_H */