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
  42 /*
  43  * State of the slab allocator.
  44  *
  45  * This is used to describe the states of the allocator during bootup.
  46  * Allocators use this to gradually bootstrap themselves. Most allocators
  47  * have the problem that the structures used for managing slab caches are
  48  * allocated from slab caches themselves.
  49  */
  50 enum slab_state {
  51         DOWN,                   /* No slab functionality yet */
  52         PARTIAL,                /* SLUB: kmem_cache_node available */
  53         PARTIAL_NODE,           /* SLAB: kmalloc size for node struct available */
  54         UP,                     /* Slab caches usable but not all extras yet */
  55         FULL                    /* Everything is working */
  56 };
  57
  58 extern enum slab_state slab_state;
  59
  60 /* The slab cache mutex protects the management structures during changes */
  61 extern struct mutex slab_mutex;
  62
  63 /* The list of all slab caches on the system */
  64 extern struct list_head slab_caches;
  65
  66 /* The slab cache that manages slab cache information */
  67 extern struct kmem_cache *kmem_cache;
  68
  69 unsigned long calculate_alignment(unsigned long flags,
  70                 unsigned long align, unsigned long size);
  71
  72 #ifndef CONFIG_SLOB
  73 /* Kmalloc array related functions */
  74 void setup_kmalloc_cache_index_table(void);
  75 void create_kmalloc_caches(unsigned long);
  76
  77 /* Find the kmalloc slab corresponding for a certain size */
  78 struct kmem_cache *kmalloc_slab(size_t, gfp_t);
  79 #endif
  80
  81
  82 /* Functions provided by the slab allocators */
  83 extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
  84
  85 extern struct kmem_cache *create_kmalloc_cache(const char *name, size_t size,
  86                         unsigned long flags);
  87 extern void create_boot_cache(struct kmem_cache *, const char *name,
  88                         size_t size, unsigned long flags);
  89
  90 int slab_unmergeable(struct kmem_cache *s);
  91 struct kmem_cache *find_mergeable(size_t size, size_t align,
  92                 unsigned long flags, const char *name, void (*ctor)(void *));
  93 #ifndef CONFIG_SLOB
  94 struct kmem_cache *
  95 __kmem_cache_alias(const char *name, size_t size, size_t align,
  96                    unsigned long flags, void (*ctor)(void *));
  97
  98 unsigned long kmem_cache_flags(unsigned long object_size,
  99         unsigned long flags, const char *name,
 100         void (*ctor)(void *));
 101 #else
 102 static inline struct kmem_cache *
 103 __kmem_cache_alias(const char *name, size_t size, size_t align,
 104                    unsigned long flags, void (*ctor)(void *))
 105 { return NULL; }
 106
 107 static inline unsigned long kmem_cache_flags(unsigned long object_size,
 108         unsigned long flags, const char *name,
 109         void (*ctor)(void *))
 110 {
 111         return flags;
 112 }
 113 #endif
 114
 115
 116 /* Legal flag mask for kmem_cache_create(), for various configurations */
 117 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
 118                          SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS )
 119
 120 #if defined(CONFIG_DEBUG_SLAB)
 121 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 122 #elif defined(CONFIG_SLUB_DEBUG)
 123 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
 124                           SLAB_TRACE | SLAB_DEBUG_FREE)
 125 #else
 126 #define SLAB_DEBUG_FLAGS (0)
 127 #endif
 128
 129 #if defined(CONFIG_SLAB)
 130 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
 131                           SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
 132                           SLAB_NOTRACK | SLAB_ACCOUNT)
 133 #elif defined(CONFIG_SLUB)
 134 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
 135                           SLAB_TEMPORARY | SLAB_NOTRACK | SLAB_ACCOUNT)
 136 #else
 137 #define SLAB_CACHE_FLAGS (0)
 138 #endif
 139
 140 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
 141
 142 int __kmem_cache_shutdown(struct kmem_cache *);
 143 void __kmem_cache_release(struct kmem_cache *);
 144 int __kmem_cache_shrink(struct kmem_cache *, bool);
 145 void slab_kmem_cache_release(struct kmem_cache *);
 146
 147 struct seq_file;
 148 struct file;
 149
 150 struct slabinfo {
 151         unsigned long active_objs;
 152         unsigned long num_objs;
 153         unsigned long active_slabs;
 154         unsigned long num_slabs;
 155         unsigned long shared_avail;
 156         unsigned int limit;
 157         unsigned int batchcount;
 158         unsigned int shared;
 159         unsigned int objects_per_slab;
 160         unsigned int cache_order;
 161 };
 162
 163 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
 164 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
 165 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 166                        size_t count, loff_t *ppos);
 167
 168 /*
 169  * Generic implementation of bulk operations
 170  * These are useful for situations in which the allocator cannot
 171  * perform optimizations. In that case segments of the objecct listed
 172  * may be allocated or freed using these operations.
 173  */
 174 void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
 175 int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
 176
 177 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
 178 /*
 179  * Iterate over all memcg caches of the given root cache. The caller must hold
 180  * slab_mutex.
 181  */
 182 #define for_each_memcg_cache(iter, root) \
 183         list_for_each_entry(iter, &(root)->memcg_params.list, \
 184                             memcg_params.list)
 185
 186 static inline bool is_root_cache(struct kmem_cache *s)
 187 {
 188         return s->memcg_params.is_root_cache;
 189 }
 190
 191 static inline bool slab_equal_or_root(struct kmem_cache *s,
 192                                       struct kmem_cache *p)
 193 {
 194         return p == s || p == s->memcg_params.root_cache;
 195 }
 196
 197 /*
 198  * We use suffixes to the name in memcg because we can't have caches
 199  * created in the system with the same name. But when we print them
 200  * locally, better refer to them with the base name
 201  */
 202 static inline const char *cache_name(struct kmem_cache *s)
 203 {
 204         if (!is_root_cache(s))
 205                 s = s->memcg_params.root_cache;
 206         return s->name;
 207 }
 208
 209 /*
 210  * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
 211  * That said the caller must assure the memcg's cache won't go away by either
 212  * taking a css reference to the owner cgroup, or holding the slab_mutex.
 213  */
 214 static inline struct kmem_cache *
 215 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 216 {
 217         struct kmem_cache *cachep;
 218         struct memcg_cache_array *arr;
 219
 220         rcu_read_lock();
 221         arr = rcu_dereference(s->memcg_params.memcg_caches);
 222
 223         /*
 224          * Make sure we will access the up-to-date value. The code updating
 225          * memcg_caches issues a write barrier to match this (see
 226          * memcg_create_kmem_cache()).
 227          */
 228         cachep = lockless_dereference(arr->entries[idx]);
 229         rcu_read_unlock();
 230
 231         return cachep;
 232 }
 233
 234 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 235 {
 236         if (is_root_cache(s))
 237                 return s;
 238         return s->memcg_params.root_cache;
 239 }
 240
 241 static __always_inline int memcg_charge_slab(struct page *page,
 242                                              gfp_t gfp, int order,
 243                                              struct kmem_cache *s)
 244 {
 245         if (!memcg_kmem_enabled())
 246                 return 0;
 247         if (is_root_cache(s))
 248                 return 0;
 249         return __memcg_kmem_charge_memcg(page, gfp, order,
 250                                          s->memcg_params.memcg);
 251 }
 252
 253 extern void slab_init_memcg_params(struct kmem_cache *);
 254
 255 #else /* CONFIG_MEMCG && !CONFIG_SLOB */
 256
 257 #define for_each_memcg_cache(iter, root) \
 258         for ((void)(iter), (void)(root); 0; )
 259
 260 static inline bool is_root_cache(struct kmem_cache *s)
 261 {
 262         return true;
 263 }
 264
 265 static inline bool slab_equal_or_root(struct kmem_cache *s,
 266                                       struct kmem_cache *p)
 267 {
 268         return true;
 269 }
 270
 271 static inline const char *cache_name(struct kmem_cache *s)
 272 {
 273         return s->name;
 274 }
 275
 276 static inline struct kmem_cache *
 277 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 278 {
 279         return NULL;
 280 }
 281
 282 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 283 {
 284         return s;
 285 }
 286
 287 static inline int memcg_charge_slab(struct page *page, gfp_t gfp, int order,
 288                                     struct kmem_cache *s)
 289 {
 290         return 0;
 291 }
 292
 293 static inline void slab_init_memcg_params(struct kmem_cache *s)
 294 {
 295 }
 296 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */
 297
 298 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 299 {
 300         struct kmem_cache *cachep;
 301         struct page *page;
 302
 303         /*
 304          * When kmemcg is not being used, both assignments should return the
 305          * same value. but we don't want to pay the assignment price in that
 306          * case. If it is not compiled in, the compiler should be smart enough
 307          * to not do even the assignment. In that case, slab_equal_or_root
 308          * will also be a constant.
 309          */
 310         if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))
 311                 return s;
 312
 313         page = virt_to_head_page(x);
 314         cachep = page->slab_cache;
 315         if (slab_equal_or_root(cachep, s))
 316                 return cachep;
 317
 318         pr_err("%s: Wrong slab cache. %s but object is from %s\n",
 319                __func__, s->name, cachep->name);
 320         WARN_ON_ONCE(1);
 321         return s;
 322 }
 323
 324 #ifndef CONFIG_SLOB
 325 /*
 326  * The slab lists for all objects.
 327  */
 328 struct kmem_cache_node {
 329         spinlock_t list_lock;
 330
 331 #ifdef CONFIG_SLAB
 332         struct list_head slabs_partial; /* partial list first, better asm code */
 333         struct list_head slabs_full;
 334         struct list_head slabs_free;
 335         unsigned long free_objects;
 336         unsigned int free_limit;
 337         unsigned int colour_next;       /* Per-node cache coloring */
 338         struct array_cache *shared;     /* shared per node */
 339         struct alien_cache **alien;     /* on other nodes */
 340         unsigned long next_reap;        /* updated without locking */
 341         int free_touched;               /* updated without locking */
 342 #endif
 343
 344 #ifdef CONFIG_SLUB
 345         unsigned long nr_partial;
 346         struct list_head partial;
 347 #ifdef CONFIG_SLUB_DEBUG
 348         atomic_long_t nr_slabs;
 349         atomic_long_t total_objects;
 350         struct list_head full;
 351 #endif
 352 #endif
 353
 354 };
 355
 356 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 357 {
 358         return s->node[node];
 359 }
 360
 361 /*
 362  * Iterator over all nodes. The body will be executed for each node that has
 363  * a kmem_cache_node structure allocated (which is true for all online nodes)
 364  */
 365 #define for_each_kmem_cache_node(__s, __node, __n) \
 366         for (__node = 0; __node < nr_node_ids; __node++) \
 367                  if ((__n = get_node(__s, __node)))
 368
 369 #endif
 370
 371 void *slab_start(struct seq_file *m, loff_t *pos);
 372 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 373 void slab_stop(struct seq_file *m, void *p);
 374 int memcg_slab_show(struct seq_file *m, void *p);
 375
 376 #endif /* MM_SLAB_H */