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 int slab_unmergeable(struct kmem_cache *s);
  90 struct kmem_cache *find_mergeable(size_t size, size_t align,
  91                 unsigned long flags, const char *name, void (*ctor)(void *));
  92 #ifndef CONFIG_SLOB
  93 struct kmem_cache *
  94 __kmem_cache_alias(const char *name, size_t size, size_t align,
  95                    unsigned long flags, void (*ctor)(void *));
  96
  97 unsigned long kmem_cache_flags(unsigned long object_size,
  98         unsigned long flags, const char *name,
  99         void (*ctor)(void *));
 100 #else
 101 static inline struct kmem_cache *
 102 __kmem_cache_alias(const char *name, size_t size, size_t align,
 103                    unsigned long flags, void (*ctor)(void *))
 104 { return NULL; }
 105
 106 static inline unsigned long kmem_cache_flags(unsigned long object_size,
 107         unsigned long flags, const char *name,
 108         void (*ctor)(void *))
 109 {
 110         return flags;
 111 }
 112 #endif
 113
 114
 115 /* Legal flag mask for kmem_cache_create(), for various configurations */
 116 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
 117                          SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS )
 118
 119 #if defined(CONFIG_DEBUG_SLAB)
 120 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 121 #elif defined(CONFIG_SLUB_DEBUG)
 122 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
 123                           SLAB_TRACE | SLAB_DEBUG_FREE)
 124 #else
 125 #define SLAB_DEBUG_FLAGS (0)
 126 #endif
 127
 128 #if defined(CONFIG_SLAB)
 129 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
 130                           SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | SLAB_NOTRACK)
 131 #elif defined(CONFIG_SLUB)
 132 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
 133                           SLAB_TEMPORARY | SLAB_NOTRACK)
 134 #else
 135 #define SLAB_CACHE_FLAGS (0)
 136 #endif
 137
 138 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
 139
 140 int __kmem_cache_shutdown(struct kmem_cache *);
 141 int __kmem_cache_shrink(struct kmem_cache *, bool);
 142 void slab_kmem_cache_release(struct kmem_cache *);
 143
 144 struct seq_file;
 145 struct file;
 146
 147 struct slabinfo {
 148         unsigned long active_objs;
 149         unsigned long num_objs;
 150         unsigned long active_slabs;
 151         unsigned long num_slabs;
 152         unsigned long shared_avail;
 153         unsigned int limit;
 154         unsigned int batchcount;
 155         unsigned int shared;
 156         unsigned int objects_per_slab;
 157         unsigned int cache_order;
 158 };
 159
 160 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
 161 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
 162 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 163                        size_t count, loff_t *ppos);
 164
 165 #ifdef CONFIG_MEMCG_KMEM
 166 /*
 167  * Iterate over all memcg caches of the given root cache. The caller must hold
 168  * slab_mutex.
 169  */
 170 #define for_each_memcg_cache(iter, root) \
 171         list_for_each_entry(iter, &(root)->memcg_params.list, \
 172                             memcg_params.list)
 173
 174 #define for_each_memcg_cache_safe(iter, tmp, root) \
 175         list_for_each_entry_safe(iter, tmp, &(root)->memcg_params.list, \
 176                                  memcg_params.list)
 177
 178 static inline bool is_root_cache(struct kmem_cache *s)
 179 {
 180         return s->memcg_params.is_root_cache;
 181 }
 182
 183 static inline bool slab_equal_or_root(struct kmem_cache *s,
 184                                       struct kmem_cache *p)
 185 {
 186         return p == s || p == s->memcg_params.root_cache;
 187 }
 188
 189 /*
 190  * We use suffixes to the name in memcg because we can't have caches
 191  * created in the system with the same name. But when we print them
 192  * locally, better refer to them with the base name
 193  */
 194 static inline const char *cache_name(struct kmem_cache *s)
 195 {
 196         if (!is_root_cache(s))
 197                 s = s->memcg_params.root_cache;
 198         return s->name;
 199 }
 200
 201 /*
 202  * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
 203  * That said the caller must assure the memcg's cache won't go away by either
 204  * taking a css reference to the owner cgroup, or holding the slab_mutex.
 205  */
 206 static inline struct kmem_cache *
 207 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 208 {
 209         struct kmem_cache *cachep;
 210         struct memcg_cache_array *arr;
 211
 212         rcu_read_lock();
 213         arr = rcu_dereference(s->memcg_params.memcg_caches);
 214
 215         /*
 216          * Make sure we will access the up-to-date value. The code updating
 217          * memcg_caches issues a write barrier to match this (see
 218          * memcg_create_kmem_cache()).
 219          */
 220         cachep = lockless_dereference(arr->entries[idx]);
 221         rcu_read_unlock();
 222
 223         return cachep;
 224 }
 225
 226 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 227 {
 228         if (is_root_cache(s))
 229                 return s;
 230         return s->memcg_params.root_cache;
 231 }
 232
 233 static __always_inline int memcg_charge_slab(struct kmem_cache *s,
 234                                              gfp_t gfp, int order)
 235 {
 236         if (!memcg_kmem_enabled())
 237                 return 0;
 238         if (is_root_cache(s))
 239                 return 0;
 240         return memcg_charge_kmem(s->memcg_params.memcg, gfp, 1 << order);
 241 }
 242
 243 static __always_inline void memcg_uncharge_slab(struct kmem_cache *s, int order)
 244 {
 245         if (!memcg_kmem_enabled())
 246                 return;
 247         if (is_root_cache(s))
 248                 return;
 249         memcg_uncharge_kmem(s->memcg_params.memcg, 1 << order);
 250 }
 251
 252 extern void slab_init_memcg_params(struct kmem_cache *);
 253
 254 #else /* !CONFIG_MEMCG_KMEM */
 255
 256 #define for_each_memcg_cache(iter, root) \
 257         for ((void)(iter), (void)(root); 0; )
 258 #define for_each_memcg_cache_safe(iter, tmp, root) \
 259         for ((void)(iter), (void)(tmp), (void)(root); 0; )
 260
 261 static inline bool is_root_cache(struct kmem_cache *s)
 262 {
 263         return true;
 264 }
 265
 266 static inline bool slab_equal_or_root(struct kmem_cache *s,
 267                                       struct kmem_cache *p)
 268 {
 269         return true;
 270 }
 271
 272 static inline const char *cache_name(struct kmem_cache *s)
 273 {
 274         return s->name;
 275 }
 276
 277 static inline struct kmem_cache *
 278 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 279 {
 280         return NULL;
 281 }
 282
 283 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 284 {
 285         return s;
 286 }
 287
 288 static inline int memcg_charge_slab(struct kmem_cache *s, gfp_t gfp, int order)
 289 {
 290         return 0;
 291 }
 292
 293 static inline void memcg_uncharge_slab(struct kmem_cache *s, int order)
 294 {
 295 }
 296
 297 static inline void slab_init_memcg_params(struct kmem_cache *s)
 298 {
 299 }
 300 #endif /* CONFIG_MEMCG_KMEM */
 301
 302 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 303 {
 304         struct kmem_cache *cachep;
 305         struct page *page;
 306
 307         /*
 308          * When kmemcg is not being used, both assignments should return the
 309          * same value. but we don't want to pay the assignment price in that
 310          * case. If it is not compiled in, the compiler should be smart enough
 311          * to not do even the assignment. In that case, slab_equal_or_root
 312          * will also be a constant.
 313          */
 314         if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))
 315                 return s;
 316
 317         page = virt_to_head_page(x);
 318         cachep = page->slab_cache;
 319         if (slab_equal_or_root(cachep, s))
 320                 return cachep;
 321
 322         pr_err("%s: Wrong slab cache. %s but object is from %s\n",
 323                __func__, cachep->name, s->name);
 324         WARN_ON_ONCE(1);
 325         return s;
 326 }
 327
 328 #ifndef CONFIG_SLOB
 329 /*
 330  * The slab lists for all objects.
 331  */
 332 struct kmem_cache_node {
 333         spinlock_t list_lock;
 334
 335 #ifdef CONFIG_SLAB
 336         struct list_head slabs_partial; /* partial list first, better asm code */
 337         struct list_head slabs_full;
 338         struct list_head slabs_free;
 339         unsigned long free_objects;
 340         unsigned int free_limit;
 341         unsigned int colour_next;       /* Per-node cache coloring */
 342         struct array_cache *shared;     /* shared per node */
 343         struct alien_cache **alien;     /* on other nodes */
 344         unsigned long next_reap;        /* updated without locking */
 345         int free_touched;               /* updated without locking */
 346 #endif
 347
 348 #ifdef CONFIG_SLUB
 349         unsigned long nr_partial;
 350         struct list_head partial;
 351 #ifdef CONFIG_SLUB_DEBUG
 352         atomic_long_t nr_slabs;
 353         atomic_long_t total_objects;
 354         struct list_head full;
 355 #endif
 356 #endif
 357
 358 };
 359
 360 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 361 {
 362         return s->node[node];
 363 }
 364
 365 /*
 366  * Iterator over all nodes. The body will be executed for each node that has
 367  * a kmem_cache_node structure allocated (which is true for all online nodes)
 368  */
 369 #define for_each_kmem_cache_node(__s, __node, __n) \
 370         for (__node = 0; __node < nr_node_ids; __node++) \
 371                  if ((__n = get_node(__s, __node)))
 372
 373 #endif
 374
 375 void *slab_start(struct seq_file *m, loff_t *pos);
 376 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 377 void slab_stop(struct seq_file *m, void *p);
 378 int memcg_slab_show(struct seq_file *m, void *p);
 379
 380 #endif /* MM_SLAB_H */