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