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