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