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
  95 struct seq_file;
  96 struct file;
  97
  98 struct slabinfo {
  99         unsigned long active_objs;
 100         unsigned long num_objs;
 101         unsigned long active_slabs;
 102         unsigned long num_slabs;
 103         unsigned long shared_avail;
 104         unsigned int limit;
 105         unsigned int batchcount;
 106         unsigned int shared;
 107         unsigned int objects_per_slab;
 108         unsigned int cache_order;
 109 };
 110
 111 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
 112 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
 113 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 114                        size_t count, loff_t *ppos);
 115
 116 #ifdef CONFIG_MEMCG_KMEM
 117 static inline bool is_root_cache(struct kmem_cache *s)
 118 {
 119         return !s->memcg_params || s->memcg_params->is_root_cache;
 120 }
 121
 122 static inline void memcg_bind_pages(struct kmem_cache *s, int order)
 123 {
 124         if (!is_root_cache(s))
 125                 atomic_add(1 << order, &s->memcg_params->nr_pages);
 126 }
 127
 128 static inline void memcg_release_pages(struct kmem_cache *s, int order)
 129 {
 130         if (is_root_cache(s))
 131                 return;
 132
 133         if (atomic_sub_and_test((1 << order), &s->memcg_params->nr_pages))
 134                 mem_cgroup_destroy_cache(s);
 135 }
 136
 137 static inline bool slab_equal_or_root(struct kmem_cache *s,
 138                                         struct kmem_cache *p)
 139 {
 140         return (p == s) ||
 141                 (s->memcg_params && (p == s->memcg_params->root_cache));
 142 }
 143
 144 /*
 145  * We use suffixes to the name in memcg because we can't have caches
 146  * created in the system with the same name. But when we print them
 147  * locally, better refer to them with the base name
 148  */
 149 static inline const char *cache_name(struct kmem_cache *s)
 150 {
 151         if (!is_root_cache(s))
 152                 return s->memcg_params->root_cache->name;
 153         return s->name;
 154 }
 155
 156 /*
 157  * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
 158  * That said the caller must assure the memcg's cache won't go away. Since once
 159  * created a memcg's cache is destroyed only along with the root cache, it is
 160  * true if we are going to allocate from the cache or hold a reference to the
 161  * root cache by other means. Otherwise, we should hold either the slab_mutex
 162  * or the memcg's slab_caches_mutex while calling this function and accessing
 163  * the returned value.
 164  */
 165 static inline struct kmem_cache *
 166 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 167 {
 168         struct kmem_cache *cachep;
 169         struct memcg_cache_params *params;
 170
 171         if (!s->memcg_params)
 172                 return NULL;
 173
 174         rcu_read_lock();
 175         params = rcu_dereference(s->memcg_params);
 176         cachep = params->memcg_caches[idx];
 177         rcu_read_unlock();
 178
 179         /*
 180          * Make sure we will access the up-to-date value. The code updating
 181          * memcg_caches issues a write barrier to match this (see
 182          * memcg_register_cache()).
 183          */
 184         smp_read_barrier_depends();
 185         return cachep;
 186 }
 187
 188 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 189 {
 190         if (is_root_cache(s))
 191                 return s;
 192         return s->memcg_params->root_cache;
 193 }
 194 #else
 195 static inline bool is_root_cache(struct kmem_cache *s)
 196 {
 197         return true;
 198 }
 199
 200 static inline void memcg_bind_pages(struct kmem_cache *s, int order)
 201 {
 202 }
 203
 204 static inline void memcg_release_pages(struct kmem_cache *s, int order)
 205 {
 206 }
 207
 208 static inline bool slab_equal_or_root(struct kmem_cache *s,
 209                                       struct kmem_cache *p)
 210 {
 211         return true;
 212 }
 213
 214 static inline const char *cache_name(struct kmem_cache *s)
 215 {
 216         return s->name;
 217 }
 218
 219 static inline struct kmem_cache *
 220 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 221 {
 222         return NULL;
 223 }
 224
 225 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 226 {
 227         return s;
 228 }
 229 #endif
 230
 231 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 232 {
 233         struct kmem_cache *cachep;
 234         struct page *page;
 235
 236         /*
 237          * When kmemcg is not being used, both assignments should return the
 238          * same value. but we don't want to pay the assignment price in that
 239          * case. If it is not compiled in, the compiler should be smart enough
 240          * to not do even the assignment. In that case, slab_equal_or_root
 241          * will also be a constant.
 242          */
 243         if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))
 244                 return s;
 245
 246         page = virt_to_head_page(x);
 247         cachep = page->slab_cache;
 248         if (slab_equal_or_root(cachep, s))
 249                 return cachep;
 250
 251         pr_err("%s: Wrong slab cache. %s but object is from %s\n",
 252                 __FUNCTION__, cachep->name, s->name);
 253         WARN_ON_ONCE(1);
 254         return s;
 255 }
 256 #endif
 257
 258
 259 /*
 260  * The slab lists for all objects.
 261  */
 262 struct kmem_cache_node {
 263         spinlock_t list_lock;
 264
 265 #ifdef CONFIG_SLAB
 266         struct list_head slabs_partial; /* partial list first, better asm code */
 267         struct list_head slabs_full;
 268         struct list_head slabs_free;
 269         unsigned long free_objects;
 270         unsigned int free_limit;
 271         unsigned int colour_next;       /* Per-node cache coloring */
 272         struct array_cache *shared;     /* shared per node */
 273         struct array_cache **alien;     /* on other nodes */
 274         unsigned long next_reap;        /* updated without locking */
 275         int free_touched;               /* updated without locking */
 276 #endif
 277
 278 #ifdef CONFIG_SLUB
 279         unsigned long nr_partial;
 280         struct list_head partial;
 281 #ifdef CONFIG_SLUB_DEBUG
 282         atomic_long_t nr_slabs;
 283         atomic_long_t total_objects;
 284         struct list_head full;
 285 #endif
 286 #endif
 287
 288 };
 289
 290 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 291 void slab_stop(struct seq_file *m, void *p);