mm/slab.h

   1 #ifndef MM_SLAB_H
   2 #define MM_SLAB_H
   3 /*
   4  * Internal slab definitions
   5  */
   6
   7 /*
   8  * State of the slab allocator.
   9  *
  10  * This is used to describe the states of the allocator during bootup.
  11  * Allocators use this to gradually bootstrap themselves. Most allocators
  12  * have the problem that the structures used for managing slab caches are
  13  * allocated from slab caches themselves.
  14  */
  15 enum slab_state {
  16         DOWN,                   /* No slab functionality yet */
  17         PARTIAL,                /* SLUB: kmem_cache_node available */
  18         PARTIAL_ARRAYCACHE,     /* SLAB: kmalloc size for arraycache available */
  19         PARTIAL_NODE,           /* SLAB: kmalloc size for node struct available */
  20         UP,                     /* Slab caches usable but not all extras yet */
  21         FULL                    /* Everything is working */
  22 };
  23
  24 extern enum slab_state slab_state;
  25
  26 /* The slab cache mutex protects the management structures during changes */
  27 extern struct mutex slab_mutex;
  28
  29 /* The list of all slab caches on the system */
  30 extern struct list_head slab_caches;
  31
  32 /* The slab cache that manages slab cache information */
  33 extern struct kmem_cache *kmem_cache;
  34
  35 unsigned long calculate_alignment(unsigned long flags,
  36                 unsigned long align, unsigned long size);
  37
  38 #ifndef CONFIG_SLOB
  39 /* Kmalloc array related functions */
  40 void create_kmalloc_caches(unsigned long);
  41
  42 /* Find the kmalloc slab corresponding for a certain size */
  43 struct kmem_cache *kmalloc_slab(size_t, gfp_t);
  44 #endif
  45
  46
  47 /* Functions provided by the slab allocators */
  48 extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
  49
  50 extern struct kmem_cache *create_kmalloc_cache(const char *name, size_t size,
  51                         unsigned long flags);
  52 extern void create_boot_cache(struct kmem_cache *, const char *name,
  53                         size_t size, unsigned long flags);
  54
  55 struct mem_cgroup;
  56 #ifdef CONFIG_SLUB
  57 struct kmem_cache *
  58 __kmem_cache_alias(const char *name, size_t size, size_t align,
  59                    unsigned long flags, void (*ctor)(void *));
  60 #else
  61 static inline struct kmem_cache *
  62 __kmem_cache_alias(const char *name, size_t size, size_t align,
  63                    unsigned long flags, void (*ctor)(void *))
  64 { return NULL; }
  65 #endif
  66
  67
  68 /* Legal flag mask for kmem_cache_create(), for various configurations */
  69 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
  70                          SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS )
  71
  72 #if defined(CONFIG_DEBUG_SLAB)
  73 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
  74 #elif defined(CONFIG_SLUB_DEBUG)
  75 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
  76                           SLAB_TRACE | SLAB_DEBUG_FREE)
  77 #else
  78 #define SLAB_DEBUG_FLAGS (0)
  79 #endif
  80
  81 #if defined(CONFIG_SLAB)
  82 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
  83                           SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | SLAB_NOTRACK)
  84 #elif defined(CONFIG_SLUB)
  85 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
  86                           SLAB_TEMPORARY | SLAB_NOTRACK)
  87 #else
  88 #define SLAB_CACHE_FLAGS (0)
  89 #endif
  90
  91 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
  92
  93 int __kmem_cache_shutdown(struct kmem_cache *);
  94 int __kmem_cache_shrink(struct kmem_cache *);
  95 void slab_kmem_cache_release(struct kmem_cache *);
  96
  97 struct seq_file;
  98 struct file;
  99
 100 struct slabinfo {
 101         unsigned long active_objs;
 102         unsigned long num_objs;
 103         unsigned long active_slabs;
 104         unsigned long num_slabs;
 105         unsigned long shared_avail;
 106         unsigned int limit;
 107         unsigned int batchcount;
 108         unsigned int shared;
 109         unsigned int objects_per_slab;
 110         unsigned int cache_order;
 111 };
 112
 113 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
 114 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
 115 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 116                        size_t count, loff_t *ppos);
 117
 118 #ifdef CONFIG_MEMCG_KMEM
 119 static inline bool is_root_cache(struct kmem_cache *s)
 120 {
 121         return !s->memcg_params || s->memcg_params->is_root_cache;
 122 }
 123
 124 static inline bool slab_equal_or_root(struct kmem_cache *s,
 125                                         struct kmem_cache *p)
 126 {
 127         return (p == s) ||
 128                 (s->memcg_params && (p == s->memcg_params->root_cache));
 129 }
 130
 131 /*
 132  * We use suffixes to the name in memcg because we can't have caches
 133  * created in the system with the same name. But when we print them
 134  * locally, better refer to them with the base name
 135  */
 136 static inline const char *cache_name(struct kmem_cache *s)
 137 {
 138         if (!is_root_cache(s))
 139                 return s->memcg_params->root_cache->name;
 140         return s->name;
 141 }
 142
 143 /*
 144  * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
 145  * That said the caller must assure the memcg's cache won't go away. Since once
 146  * created a memcg's cache is destroyed only along with the root cache, it is
 147  * true if we are going to allocate from the cache or hold a reference to the
 148  * root cache by other means. Otherwise, we should hold either the slab_mutex
 149  * or the memcg's slab_caches_mutex while calling this function and accessing
 150  * the returned value.
 151  */
 152 static inline struct kmem_cache *
 153 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 154 {
 155         struct kmem_cache *cachep;
 156         struct memcg_cache_params *params;
 157
 158         if (!s->memcg_params)
 159                 return NULL;
 160
 161         rcu_read_lock();
 162         params = rcu_dereference(s->memcg_params);
 163         cachep = params->memcg_caches[idx];
 164         rcu_read_unlock();
 165
 166         /*
 167          * Make sure we will access the up-to-date value. The code updating
 168          * memcg_caches issues a write barrier to match this (see
 169          * memcg_register_cache()).
 170          */
 171         smp_read_barrier_depends();
 172         return cachep;
 173 }
 174
 175 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 176 {
 177         if (is_root_cache(s))
 178                 return s;
 179         return s->memcg_params->root_cache;
 180 }
 181
 182 static __always_inline int memcg_charge_slab(struct kmem_cache *s,
 183                                              gfp_t gfp, int order)
 184 {
 185         if (!memcg_kmem_enabled())
 186                 return 0;
 187         if (is_root_cache(s))
 188                 return 0;
 189         return __memcg_charge_slab(s, gfp, order);
 190 }
 191
 192 static __always_inline void memcg_uncharge_slab(struct kmem_cache *s, int order)
 193 {
 194         if (!memcg_kmem_enabled())
 195                 return;
 196         if (is_root_cache(s))
 197                 return;
 198         __memcg_uncharge_slab(s, order);
 199 }
 200 #else
 201 static inline bool is_root_cache(struct kmem_cache *s)
 202 {
 203         return true;
 204 }
 205
 206 static inline bool slab_equal_or_root(struct kmem_cache *s,
 207                                       struct kmem_cache *p)
 208 {
 209         return true;
 210 }
 211
 212 static inline const char *cache_name(struct kmem_cache *s)
 213 {
 214         return s->name;
 215 }
 216
 217 static inline struct kmem_cache *
 218 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 219 {
 220         return NULL;
 221 }
 222
 223 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 224 {
 225         return s;
 226 }
 227
 228 static inline int memcg_charge_slab(struct kmem_cache *s, gfp_t gfp, int order)
 229 {
 230         return 0;
 231 }
 232
 233 static inline void memcg_uncharge_slab(struct kmem_cache *s, int order)
 234 {
 235 }
 236 #endif
 237
 238 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 239 {
 240         struct kmem_cache *cachep;
 241         struct page *page;
 242
 243         /*
 244          * When kmemcg is not being used, both assignments should return the
 245          * same value. but we don't want to pay the assignment price in that
 246          * case. If it is not compiled in, the compiler should be smart enough
 247          * to not do even the assignment. In that case, slab_equal_or_root
 248          * will also be a constant.
 249          */
 250         if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))
 251                 return s;
 252
 253         page = virt_to_head_page(x);
 254         cachep = page->slab_cache;
 255         if (slab_equal_or_root(cachep, s))
 256                 return cachep;
 257
 258         pr_err("%s: Wrong slab cache. %s but object is from %s\n",
 259                 __FUNCTION__, cachep->name, s->name);
 260         WARN_ON_ONCE(1);
 261         return s;
 262 }
 263 #endif
 264
 265
 266 /*
 267  * The slab lists for all objects.
 268  */
 269 struct kmem_cache_node {
 270         spinlock_t list_lock;
 271
 272 #ifdef CONFIG_SLAB
 273         struct list_head slabs_partial; /* partial list first, better asm code */
 274         struct list_head slabs_full;
 275         struct list_head slabs_free;
 276         unsigned long free_objects;
 277         unsigned int free_limit;
 278         unsigned int colour_next;       /* Per-node cache coloring */
 279         struct array_cache *shared;     /* shared per node */
 280         struct array_cache **alien;     /* on other nodes */
 281         unsigned long next_reap;        /* updated without locking */
 282         int free_touched;               /* updated without locking */
 283 #endif
 284
 285 #ifdef CONFIG_SLUB
 286         unsigned long nr_partial;
 287         struct list_head partial;
 288 #ifdef CONFIG_SLUB_DEBUG
 289         atomic_long_t nr_slabs;
 290         atomic_long_t total_objects;
 291         struct list_head full;
 292 #endif
 293 #endif
 294
 295 };
 296
 297 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 298 void slab_stop(struct seq_file *m, void *p);