mm/slab.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef MM_SLAB_H
   3 #define MM_SLAB_H
   4 /*
   5  * Internal slab definitions
   6  */
   7
   8 #ifdef CONFIG_SLOB
   9 /*
  10  * Common fields provided in kmem_cache by all slab allocators
  11  * This struct is either used directly by the allocator (SLOB)
  12  * or the allocator must include definitions for all fields
  13  * provided in kmem_cache_common in their definition of kmem_cache.
  14  *
  15  * Once we can do anonymous structs (C11 standard) we could put a
  16  * anonymous struct definition in these allocators so that the
  17  * separate allocations in the kmem_cache structure of SLAB and
  18  * SLUB is no longer needed.
  19  */
  20 struct kmem_cache {
  21         unsigned int object_size;/* The original size of the object */
  22         unsigned int size;      /* The aligned/padded/added on size  */
  23         unsigned int align;     /* Alignment as calculated */
  24         slab_flags_t flags;     /* Active flags on the slab */
  25         unsigned int useroffset;/* Usercopy region offset */
  26         unsigned int usersize;  /* Usercopy region size */
  27         const char *name;       /* Slab name for sysfs */
  28         int refcount;           /* Use counter */
  29         void (*ctor)(void *);   /* Called on object slot creation */
  30         struct list_head list;  /* List of all slab caches on the system */
  31 };
  32
  33 #endif /* CONFIG_SLOB */
  34
  35 #ifdef CONFIG_SLAB
  36 #include <linux/slab_def.h>
  37 #endif
  38
  39 #ifdef CONFIG_SLUB
  40 #include <linux/slub_def.h>
  41 #endif
  42
  43 #include <linux/memcontrol.h>
  44 #include <linux/fault-inject.h>
  45 #include <linux/kasan.h>
  46 #include <linux/kmemleak.h>
  47 #include <linux/random.h>
  48 #include <linux/sched/mm.h>
  49
  50 /*
  51  * State of the slab allocator.
  52  *
  53  * This is used to describe the states of the allocator during bootup.
  54  * Allocators use this to gradually bootstrap themselves. Most allocators
  55  * have the problem that the structures used for managing slab caches are
  56  * allocated from slab caches themselves.
  57  */
  58 enum slab_state {
  59         DOWN,                   /* No slab functionality yet */
  60         PARTIAL,                /* SLUB: kmem_cache_node available */
  61         PARTIAL_NODE,           /* SLAB: kmalloc size for node struct available */
  62         UP,                     /* Slab caches usable but not all extras yet */
  63         FULL                    /* Everything is working */
  64 };
  65
  66 extern enum slab_state slab_state;
  67
  68 /* The slab cache mutex protects the management structures during changes */
  69 extern struct mutex slab_mutex;
  70
  71 /* The list of all slab caches on the system */
  72 extern struct list_head slab_caches;
  73
  74 /* The slab cache that manages slab cache information */
  75 extern struct kmem_cache *kmem_cache;
  76
  77 /* A table of kmalloc cache names and sizes */
  78 extern const struct kmalloc_info_struct {
  79         const char *name;
  80         unsigned int size;
  81 } kmalloc_info[];
  82
  83 #ifndef CONFIG_SLOB
  84 /* Kmalloc array related functions */
  85 void setup_kmalloc_cache_index_table(void);
  86 void create_kmalloc_caches(slab_flags_t);
  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 int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
  95
  96 struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size,
  97                         slab_flags_t flags, unsigned int useroffset,
  98                         unsigned int usersize);
  99 extern void create_boot_cache(struct kmem_cache *, const char *name,
 100                         unsigned int size, slab_flags_t flags,
 101                         unsigned int useroffset, unsigned int usersize);
 102
 103 int slab_unmergeable(struct kmem_cache *s);
 104 struct kmem_cache *find_mergeable(unsigned size, unsigned align,
 105                 slab_flags_t flags, const char *name, void (*ctor)(void *));
 106 #ifndef CONFIG_SLOB
 107 struct kmem_cache *
 108 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 109                    slab_flags_t flags, void (*ctor)(void *));
 110
 111 slab_flags_t kmem_cache_flags(unsigned int object_size,
 112         slab_flags_t flags, const char *name,
 113         void (*ctor)(void *));
 114 #else
 115 static inline struct kmem_cache *
 116 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 117                    slab_flags_t flags, void (*ctor)(void *))
 118 { return NULL; }
 119
 120 static inline slab_flags_t kmem_cache_flags(unsigned int object_size,
 121         slab_flags_t flags, const char *name,
 122         void (*ctor)(void *))
 123 {
 124         return flags;
 125 }
 126 #endif
 127
 128
 129 /* Legal flag mask for kmem_cache_create(), for various configurations */
 130 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
 131                          SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
 132
 133 #if defined(CONFIG_DEBUG_SLAB)
 134 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 135 #elif defined(CONFIG_SLUB_DEBUG)
 136 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
 137                           SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
 138 #else
 139 #define SLAB_DEBUG_FLAGS (0)
 140 #endif
 141
 142 #if defined(CONFIG_SLAB)
 143 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
 144                           SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
 145                           SLAB_ACCOUNT)
 146 #elif defined(CONFIG_SLUB)
 147 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
 148                           SLAB_TEMPORARY | SLAB_ACCOUNT)
 149 #else
 150 #define SLAB_CACHE_FLAGS (0)
 151 #endif
 152
 153 /* Common flags available with current configuration */
 154 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
 155
 156 /* Common flags permitted for kmem_cache_create */
 157 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
 158                               SLAB_RED_ZONE | \
 159                               SLAB_POISON | \
 160                               SLAB_STORE_USER | \
 161                               SLAB_TRACE | \
 162                               SLAB_CONSISTENCY_CHECKS | \
 163                               SLAB_MEM_SPREAD | \
 164                               SLAB_NOLEAKTRACE | \
 165                               SLAB_RECLAIM_ACCOUNT | \
 166                               SLAB_TEMPORARY | \
 167                               SLAB_ACCOUNT)
 168
 169 bool __kmem_cache_empty(struct kmem_cache *);
 170 int __kmem_cache_shutdown(struct kmem_cache *);
 171 void __kmem_cache_release(struct kmem_cache *);
 172 int __kmem_cache_shrink(struct kmem_cache *);
 173 void __kmemcg_cache_deactivate(struct kmem_cache *s);
 174 void slab_kmem_cache_release(struct kmem_cache *);
 175
 176 struct seq_file;
 177 struct file;
 178
 179 struct slabinfo {
 180         unsigned long active_objs;
 181         unsigned long num_objs;
 182         unsigned long active_slabs;
 183         unsigned long num_slabs;
 184         unsigned long shared_avail;
 185         unsigned int limit;
 186         unsigned int batchcount;
 187         unsigned int shared;
 188         unsigned int objects_per_slab;
 189         unsigned int cache_order;
 190 };
 191
 192 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
 193 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
 194 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 195                        size_t count, loff_t *ppos);
 196
 197 /*
 198  * Generic implementation of bulk operations
 199  * These are useful for situations in which the allocator cannot
 200  * perform optimizations. In that case segments of the object listed
 201  * may be allocated or freed using these operations.
 202  */
 203 void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
 204 int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
 205
 206 #ifdef CONFIG_MEMCG_KMEM
 207
 208 /* List of all root caches. */
 209 extern struct list_head         slab_root_caches;
 210 #define root_caches_node        memcg_params.__root_caches_node
 211
 212 /*
 213  * Iterate over all memcg caches of the given root cache. The caller must hold
 214  * slab_mutex.
 215  */
 216 #define for_each_memcg_cache(iter, root) \
 217         list_for_each_entry(iter, &(root)->memcg_params.children, \
 218                             memcg_params.children_node)
 219
 220 static inline bool is_root_cache(struct kmem_cache *s)
 221 {
 222         return !s->memcg_params.root_cache;
 223 }
 224
 225 static inline bool slab_equal_or_root(struct kmem_cache *s,
 226                                       struct kmem_cache *p)
 227 {
 228         return p == s || p == s->memcg_params.root_cache;
 229 }
 230
 231 /*
 232  * We use suffixes to the name in memcg because we can't have caches
 233  * created in the system with the same name. But when we print them
 234  * locally, better refer to them with the base name
 235  */
 236 static inline const char *cache_name(struct kmem_cache *s)
 237 {
 238         if (!is_root_cache(s))
 239                 s = s->memcg_params.root_cache;
 240         return s->name;
 241 }
 242
 243 /*
 244  * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
 245  * That said the caller must assure the memcg's cache won't go away by either
 246  * taking a css reference to the owner cgroup, or holding the slab_mutex.
 247  */
 248 static inline struct kmem_cache *
 249 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 250 {
 251         struct kmem_cache *cachep;
 252         struct memcg_cache_array *arr;
 253
 254         rcu_read_lock();
 255         arr = rcu_dereference(s->memcg_params.memcg_caches);
 256
 257         /*
 258          * Make sure we will access the up-to-date value. The code updating
 259          * memcg_caches issues a write barrier to match this (see
 260          * memcg_create_kmem_cache()).
 261          */
 262         cachep = READ_ONCE(arr->entries[idx]);
 263         rcu_read_unlock();
 264
 265         return cachep;
 266 }
 267
 268 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 269 {
 270         if (is_root_cache(s))
 271                 return s;
 272         return s->memcg_params.root_cache;
 273 }
 274
 275 static __always_inline int memcg_charge_slab(struct page *page,
 276                                              gfp_t gfp, int order,
 277                                              struct kmem_cache *s)
 278 {
 279         if (!memcg_kmem_enabled())
 280                 return 0;
 281         if (is_root_cache(s))
 282                 return 0;
 283         return memcg_kmem_charge_memcg(page, gfp, order, s->memcg_params.memcg);
 284 }
 285
 286 static __always_inline void memcg_uncharge_slab(struct page *page, int order,
 287                                                 struct kmem_cache *s)
 288 {
 289         if (!memcg_kmem_enabled())
 290                 return;
 291         memcg_kmem_uncharge(page, order);
 292 }
 293
 294 extern void slab_init_memcg_params(struct kmem_cache *);
 295 extern void memcg_link_cache(struct kmem_cache *s);
 296 extern void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s,
 297                                 void (*deact_fn)(struct kmem_cache *));
 298
 299 #else /* CONFIG_MEMCG_KMEM */
 300
 301 /* If !memcg, all caches are root. */
 302 #define slab_root_caches        slab_caches
 303 #define root_caches_node        list
 304
 305 #define for_each_memcg_cache(iter, root) \
 306         for ((void)(iter), (void)(root); 0; )
 307
 308 static inline bool is_root_cache(struct kmem_cache *s)
 309 {
 310         return true;
 311 }
 312
 313 static inline bool slab_equal_or_root(struct kmem_cache *s,
 314                                       struct kmem_cache *p)
 315 {
 316         return true;
 317 }
 318
 319 static inline const char *cache_name(struct kmem_cache *s)
 320 {
 321         return s->name;
 322 }
 323
 324 static inline struct kmem_cache *
 325 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 326 {
 327         return NULL;
 328 }
 329
 330 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 331 {
 332         return s;
 333 }
 334
 335 static inline int memcg_charge_slab(struct page *page, gfp_t gfp, int order,
 336                                     struct kmem_cache *s)
 337 {
 338         return 0;
 339 }
 340
 341 static inline void memcg_uncharge_slab(struct page *page, int order,
 342                                        struct kmem_cache *s)
 343 {
 344 }
 345
 346 static inline void slab_init_memcg_params(struct kmem_cache *s)
 347 {
 348 }
 349
 350 static inline void memcg_link_cache(struct kmem_cache *s)
 351 {
 352 }
 353
 354 #endif /* CONFIG_MEMCG_KMEM */
 355
 356 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 357 {
 358         struct kmem_cache *cachep;
 359         struct page *page;
 360
 361         /*
 362          * When kmemcg is not being used, both assignments should return the
 363          * same value. but we don't want to pay the assignment price in that
 364          * case. If it is not compiled in, the compiler should be smart enough
 365          * to not do even the assignment. In that case, slab_equal_or_root
 366          * will also be a constant.
 367          */
 368         if (!memcg_kmem_enabled() &&
 369             !unlikely(s->flags & SLAB_CONSISTENCY_CHECKS))
 370                 return s;
 371
 372         page = virt_to_head_page(x);
 373         cachep = page->slab_cache;
 374         if (slab_equal_or_root(cachep, s))
 375                 return cachep;
 376
 377         pr_err("%s: Wrong slab cache. %s but object is from %s\n",
 378                __func__, s->name, cachep->name);
 379         WARN_ON_ONCE(1);
 380         return s;
 381 }
 382
 383 static inline size_t slab_ksize(const struct kmem_cache *s)
 384 {
 385 #ifndef CONFIG_SLUB
 386         return s->object_size;
 387
 388 #else /* CONFIG_SLUB */
 389 # ifdef CONFIG_SLUB_DEBUG
 390         /*
 391          * Debugging requires use of the padding between object
 392          * and whatever may come after it.
 393          */
 394         if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
 395                 return s->object_size;
 396 # endif
 397         if (s->flags & SLAB_KASAN)
 398                 return s->object_size;
 399         /*
 400          * If we have the need to store the freelist pointer
 401          * back there or track user information then we can
 402          * only use the space before that information.
 403          */
 404         if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER))
 405                 return s->inuse;
 406         /*
 407          * Else we can use all the padding etc for the allocation
 408          */
 409         return s->size;
 410 #endif
 411 }
 412
 413 static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
 414                                                      gfp_t flags)
 415 {
 416         flags &= gfp_allowed_mask;
 417
 418         fs_reclaim_acquire(flags);
 419         fs_reclaim_release(flags);
 420
 421         might_sleep_if(gfpflags_allow_blocking(flags));
 422
 423         if (should_failslab(s, flags))
 424                 return NULL;
 425
 426         if (memcg_kmem_enabled() &&
 427             ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
 428                 return memcg_kmem_get_cache(s);
 429
 430         return s;
 431 }
 432
 433 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
 434                                         size_t size, void **p)
 435 {
 436         size_t i;
 437
 438         flags &= gfp_allowed_mask;
 439         for (i = 0; i < size; i++) {
 440                 void *object = p[i];
 441
 442                 kmemleak_alloc_recursive(object, s->object_size, 1,
 443                                          s->flags, flags);
 444                 kasan_slab_alloc(s, object, flags);
 445         }
 446
 447         if (memcg_kmem_enabled())
 448                 memcg_kmem_put_cache(s);
 449 }
 450
 451 #ifndef CONFIG_SLOB
 452 /*
 453  * The slab lists for all objects.
 454  */
 455 struct kmem_cache_node {
 456         spinlock_t list_lock;
 457
 458 #ifdef CONFIG_SLAB
 459         struct list_head slabs_partial; /* partial list first, better asm code */
 460         struct list_head slabs_full;
 461         struct list_head slabs_free;
 462         unsigned long total_slabs;      /* length of all slab lists */
 463         unsigned long free_slabs;       /* length of free slab list only */
 464         unsigned long free_objects;
 465         unsigned int free_limit;
 466         unsigned int colour_next;       /* Per-node cache coloring */
 467         struct array_cache *shared;     /* shared per node */
 468         struct alien_cache **alien;     /* on other nodes */
 469         unsigned long next_reap;        /* updated without locking */
 470         int free_touched;               /* updated without locking */
 471 #endif
 472
 473 #ifdef CONFIG_SLUB
 474         unsigned long nr_partial;
 475         struct list_head partial;
 476 #ifdef CONFIG_SLUB_DEBUG
 477         atomic_long_t nr_slabs;
 478         atomic_long_t total_objects;
 479         struct list_head full;
 480 #endif
 481 #endif
 482
 483 };
 484
 485 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 486 {
 487         return s->node[node];
 488 }
 489
 490 /*
 491  * Iterator over all nodes. The body will be executed for each node that has
 492  * a kmem_cache_node structure allocated (which is true for all online nodes)
 493  */
 494 #define for_each_kmem_cache_node(__s, __node, __n) \
 495         for (__node = 0; __node < nr_node_ids; __node++) \
 496                  if ((__n = get_node(__s, __node)))
 497
 498 #endif
 499
 500 void *slab_start(struct seq_file *m, loff_t *pos);
 501 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 502 void slab_stop(struct seq_file *m, void *p);
 503 void *memcg_slab_start(struct seq_file *m, loff_t *pos);
 504 void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos);
 505 void memcg_slab_stop(struct seq_file *m, void *p);
 506 int memcg_slab_show(struct seq_file *m, void *p);
 507
 508 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
 509 void dump_unreclaimable_slab(void);
 510 #else
 511 static inline void dump_unreclaimable_slab(void)
 512 {
 513 }
 514 #endif
 515
 516 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
 517
 518 #ifdef CONFIG_SLAB_FREELIST_RANDOM
 519 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
 520                         gfp_t gfp);
 521 void cache_random_seq_destroy(struct kmem_cache *cachep);
 522 #else
 523 static inline int cache_random_seq_create(struct kmem_cache *cachep,
 524                                         unsigned int count, gfp_t gfp)
 525 {
 526         return 0;
 527 }
 528 static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
 529 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
 530
 531 #endif /* MM_SLAB_H */