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 create_kmalloc_caches(unsigned long);
  75
  76 /* Find the kmalloc slab corresponding for a certain size */
  77 struct kmem_cache *kmalloc_slab(size_t, gfp_t);
  78 #endif
  79
  80
  81 /* Functions provided by the slab allocators */
  82 extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
  83
  84 extern struct kmem_cache *create_kmalloc_cache(const char *name, size_t size,
  85                         unsigned long flags);
  86 extern void create_boot_cache(struct kmem_cache *, const char *name,
  87                         size_t size, unsigned long flags);
  88
  89 struct mem_cgroup;
  90
  91 int slab_unmergeable(struct kmem_cache *s);
  92 struct kmem_cache *find_mergeable(size_t size, size_t align,
  93                 unsigned long flags, const char *name, void (*ctor)(void *));
  94 #ifndef CONFIG_SLOB
  95 struct kmem_cache *
  96 __kmem_cache_alias(const char *name, size_t size, size_t align,
  97                    unsigned long flags, void (*ctor)(void *));
  98
  99 unsigned long kmem_cache_flags(unsigned long object_size,
 100         unsigned long flags, const char *name,
 101         void (*ctor)(void *));
 102 #else
 103 static inline struct kmem_cache *
 104 __kmem_cache_alias(const char *name, size_t size, size_t align,
 105                    unsigned long flags, void (*ctor)(void *))
 106 { return NULL; }
 107
 108 static inline unsigned long kmem_cache_flags(unsigned long object_size,
 109         unsigned long flags, const char *name,
 110         void (*ctor)(void *))
 111 {
 112         return flags;
 113 }
 114 #endif
 115
 116
 117 /* Legal flag mask for kmem_cache_create(), for various configurations */
 118 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
 119                          SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS )
 120
 121 #if defined(CONFIG_DEBUG_SLAB)
 122 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 123 #elif defined(CONFIG_SLUB_DEBUG)
 124 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
 125                           SLAB_TRACE | SLAB_DEBUG_FREE)
 126 #else
 127 #define SLAB_DEBUG_FLAGS (0)
 128 #endif
 129
 130 #if defined(CONFIG_SLAB)
 131 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
 132                           SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | SLAB_NOTRACK)
 133 #elif defined(CONFIG_SLUB)
 134 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
 135                           SLAB_TEMPORARY | SLAB_NOTRACK)
 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 int __kmem_cache_shrink(struct kmem_cache *);
 144 void slab_kmem_cache_release(struct kmem_cache *);
 145
 146 struct seq_file;
 147 struct file;
 148
 149 struct slabinfo {
 150         unsigned long active_objs;
 151         unsigned long num_objs;
 152         unsigned long active_slabs;
 153         unsigned long num_slabs;
 154         unsigned long shared_avail;
 155         unsigned int limit;
 156         unsigned int batchcount;
 157         unsigned int shared;
 158         unsigned int objects_per_slab;
 159         unsigned int cache_order;
 160 };
 161
 162 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
 163 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
 164 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 165                        size_t count, loff_t *ppos);
 166
 167 #ifdef CONFIG_MEMCG_KMEM
 168 static inline bool is_root_cache(struct kmem_cache *s)
 169 {
 170         return !s->memcg_params || s->memcg_params->is_root_cache;
 171 }
 172
 173 static inline bool slab_equal_or_root(struct kmem_cache *s,
 174                                         struct kmem_cache *p)
 175 {
 176         return (p == s) ||
 177                 (s->memcg_params && (p == s->memcg_params->root_cache));
 178 }
 179
 180 /*
 181  * We use suffixes to the name in memcg because we can't have caches
 182  * created in the system with the same name. But when we print them
 183  * locally, better refer to them with the base name
 184  */
 185 static inline const char *cache_name(struct kmem_cache *s)
 186 {
 187         if (!is_root_cache(s))
 188                 return s->memcg_params->root_cache->name;
 189         return s->name;
 190 }
 191
 192 /*
 193  * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
 194  * That said the caller must assure the memcg's cache won't go away. Since once
 195  * created a memcg's cache is destroyed only along with the root cache, it is
 196  * true if we are going to allocate from the cache or hold a reference to the
 197  * root cache by other means. Otherwise, we should hold either the slab_mutex
 198  * or the memcg's slab_caches_mutex while calling this function and accessing
 199  * the returned value.
 200  */
 201 static inline struct kmem_cache *
 202 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 203 {
 204         struct kmem_cache *cachep;
 205         struct memcg_cache_params *params;
 206
 207         if (!s->memcg_params)
 208                 return NULL;
 209
 210         rcu_read_lock();
 211         params = rcu_dereference(s->memcg_params);
 212
 213         /*
 214          * Make sure we will access the up-to-date value. The code updating
 215          * memcg_caches issues a write barrier to match this (see
 216          * memcg_register_cache()).
 217          */
 218         cachep = lockless_dereference(params->memcg_caches[idx]);
 219         rcu_read_unlock();
 220
 221         return cachep;
 222 }
 223
 224 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 225 {
 226         if (is_root_cache(s))
 227                 return s;
 228         return s->memcg_params->root_cache;
 229 }
 230
 231 static __always_inline int memcg_charge_slab(struct kmem_cache *s,
 232                                              gfp_t gfp, int order)
 233 {
 234         if (!memcg_kmem_enabled())
 235                 return 0;
 236         if (is_root_cache(s))
 237                 return 0;
 238         return __memcg_charge_slab(s, gfp, order);
 239 }
 240
 241 static __always_inline void memcg_uncharge_slab(struct kmem_cache *s, int order)
 242 {
 243         if (!memcg_kmem_enabled())
 244                 return;
 245         if (is_root_cache(s))
 246                 return;
 247         __memcg_uncharge_slab(s, order);
 248 }
 249 #else
 250 static inline bool is_root_cache(struct kmem_cache *s)
 251 {
 252         return true;
 253 }
 254
 255 static inline bool slab_equal_or_root(struct kmem_cache *s,
 256                                       struct kmem_cache *p)
 257 {
 258         return true;
 259 }
 260
 261 static inline const char *cache_name(struct kmem_cache *s)
 262 {
 263         return s->name;
 264 }
 265
 266 static inline struct kmem_cache *
 267 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 268 {
 269         return NULL;
 270 }
 271
 272 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 273 {
 274         return s;
 275 }
 276
 277 static inline int memcg_charge_slab(struct kmem_cache *s, gfp_t gfp, int order)
 278 {
 279         return 0;
 280 }
 281
 282 static inline void memcg_uncharge_slab(struct kmem_cache *s, int order)
 283 {
 284 }
 285 #endif
 286
 287 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 288 {
 289         struct kmem_cache *cachep;
 290         struct page *page;
 291
 292         /*
 293          * When kmemcg is not being used, both assignments should return the
 294          * same value. but we don't want to pay the assignment price in that
 295          * case. If it is not compiled in, the compiler should be smart enough
 296          * to not do even the assignment. In that case, slab_equal_or_root
 297          * will also be a constant.
 298          */
 299         if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))
 300                 return s;
 301
 302         page = virt_to_head_page(x);
 303         cachep = page->slab_cache;
 304         if (slab_equal_or_root(cachep, s))
 305                 return cachep;
 306
 307         pr_err("%s: Wrong slab cache. %s but object is from %s\n",
 308                __func__, cachep->name, s->name);
 309         WARN_ON_ONCE(1);
 310         return s;
 311 }
 312
 313 #ifndef CONFIG_SLOB
 314 /*
 315  * The slab lists for all objects.
 316  */
 317 struct kmem_cache_node {
 318         spinlock_t list_lock;
 319
 320 #ifdef CONFIG_SLAB
 321         struct list_head slabs_partial; /* partial list first, better asm code */
 322         struct list_head slabs_full;
 323         struct list_head slabs_free;
 324         unsigned long free_objects;
 325         unsigned int free_limit;
 326         unsigned int colour_next;       /* Per-node cache coloring */
 327         struct array_cache *shared;     /* shared per node */
 328         struct alien_cache **alien;     /* on other nodes */
 329         unsigned long next_reap;        /* updated without locking */
 330         int free_touched;               /* updated without locking */
 331 #endif
 332
 333 #ifdef CONFIG_SLUB
 334         unsigned long nr_partial;
 335         struct list_head partial;
 336 #ifdef CONFIG_SLUB_DEBUG
 337         atomic_long_t nr_slabs;
 338         atomic_long_t total_objects;
 339         struct list_head full;
 340 #endif
 341 #endif
 342
 343 };
 344
 345 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 346 {
 347         return s->node[node];
 348 }
 349
 350 /*
 351  * Iterator over all nodes. The body will be executed for each node that has
 352  * a kmem_cache_node structure allocated (which is true for all online nodes)
 353  */
 354 #define for_each_kmem_cache_node(__s, __node, __n) \
 355         for (__node = 0; __node < nr_node_ids; __node++) \
 356                  if ((__n = get_node(__s, __node)))
 357
 358 #endif
 359
 360 void *slab_start(struct seq_file *m, loff_t *pos);
 361 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 362 void slab_stop(struct seq_file *m, void *p);
 363 int memcg_slab_show(struct seq_file *m, void *p);
 364
 365 #endif /* MM_SLAB_H */