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(struct mem_cgroup *memcg, const char *name, size_t size,
  59                    size_t align, unsigned long flags, void (*ctor)(void *));
  60 #else
  61 static inline struct kmem_cache *
  62 __kmem_cache_alias(struct mem_cgroup *memcg, const char *name, size_t size,
  63                    size_t align, 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 bool cache_match_memcg(struct kmem_cache *cachep,
 123                                      struct mem_cgroup *memcg)
 124 {
 125         return (is_root_cache(cachep) && !memcg) ||
 126                                 (cachep->memcg_params->memcg == memcg);
 127 }
 128
 129 static inline void memcg_bind_pages(struct kmem_cache *s, int order)
 130 {
 131         if (!is_root_cache(s))
 132                 atomic_add(1 << order, &s->memcg_params->nr_pages);
 133 }
 134
 135 static inline void memcg_release_pages(struct kmem_cache *s, int order)
 136 {
 137         if (is_root_cache(s))
 138                 return;
 139
 140         if (atomic_sub_and_test((1 << order), &s->memcg_params->nr_pages))
 141                 mem_cgroup_destroy_cache(s);
 142 }
 143
 144 static inline bool slab_equal_or_root(struct kmem_cache *s,
 145                                         struct kmem_cache *p)
 146 {
 147         return (p == s) ||
 148                 (s->memcg_params && (p == s->memcg_params->root_cache));
 149 }
 150
 151 /*
 152  * We use suffixes to the name in memcg because we can't have caches
 153  * created in the system with the same name. But when we print them
 154  * locally, better refer to them with the base name
 155  */
 156 static inline const char *cache_name(struct kmem_cache *s)
 157 {
 158         if (!is_root_cache(s))
 159                 return s->memcg_params->root_cache->name;
 160         return s->name;
 161 }
 162
 163 /*
 164  * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
 165  * That said the caller must assure the memcg's cache won't go away. Since once
 166  * created a memcg's cache is destroyed only along with the root cache, it is
 167  * true if we are going to allocate from the cache or hold a reference to the
 168  * root cache by other means. Otherwise, we should hold either the slab_mutex
 169  * or the memcg's slab_caches_mutex while calling this function and accessing
 170  * the returned value.
 171  */
 172 static inline struct kmem_cache *
 173 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 174 {
 175         struct kmem_cache *cachep;
 176         struct memcg_cache_params *params;
 177
 178         if (!s->memcg_params)
 179                 return NULL;
 180
 181         rcu_read_lock();
 182         params = rcu_dereference(s->memcg_params);
 183         cachep = params->memcg_caches[idx];
 184         rcu_read_unlock();
 185
 186         /*
 187          * Make sure we will access the up-to-date value. The code updating
 188          * memcg_caches issues a write barrier to match this (see
 189          * memcg_register_cache()).
 190          */
 191         smp_read_barrier_depends();
 192         return cachep;
 193 }
 194
 195 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 196 {
 197         if (is_root_cache(s))
 198                 return s;
 199         return s->memcg_params->root_cache;
 200 }
 201 #else
 202 static inline bool is_root_cache(struct kmem_cache *s)
 203 {
 204         return true;
 205 }
 206
 207 static inline bool cache_match_memcg(struct kmem_cache *cachep,
 208                                      struct mem_cgroup *memcg)
 209 {
 210         return true;
 211 }
 212
 213 static inline void memcg_bind_pages(struct kmem_cache *s, int order)
 214 {
 215 }
 216
 217 static inline void memcg_release_pages(struct kmem_cache *s, int order)
 218 {
 219 }
 220
 221 static inline bool slab_equal_or_root(struct kmem_cache *s,
 222                                       struct kmem_cache *p)
 223 {
 224         return true;
 225 }
 226
 227 static inline const char *cache_name(struct kmem_cache *s)
 228 {
 229         return s->name;
 230 }
 231
 232 static inline struct kmem_cache *
 233 cache_from_memcg_idx(struct kmem_cache *s, int idx)
 234 {
 235         return NULL;
 236 }
 237
 238 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 239 {
 240         return s;
 241 }
 242 #endif
 243
 244 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 245 {
 246         struct kmem_cache *cachep;
 247         struct page *page;
 248
 249         /*
 250          * When kmemcg is not being used, both assignments should return the
 251          * same value. but we don't want to pay the assignment price in that
 252          * case. If it is not compiled in, the compiler should be smart enough
 253          * to not do even the assignment. In that case, slab_equal_or_root
 254          * will also be a constant.
 255          */
 256         if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))
 257                 return s;
 258
 259         page = virt_to_head_page(x);
 260         cachep = page->slab_cache;
 261         if (slab_equal_or_root(cachep, s))
 262                 return cachep;
 263
 264         pr_err("%s: Wrong slab cache. %s but object is from %s\n",
 265                 __FUNCTION__, cachep->name, s->name);
 266         WARN_ON_ONCE(1);
 267         return s;
 268 }
 269 #endif
 270
 271
 272 /*
 273  * The slab lists for all objects.
 274  */
 275 struct kmem_cache_node {
 276         spinlock_t list_lock;
 277
 278 #ifdef CONFIG_SLAB
 279         struct list_head slabs_partial; /* partial list first, better asm code */
 280         struct list_head slabs_full;
 281         struct list_head slabs_free;
 282         unsigned long free_objects;
 283         unsigned int free_limit;
 284         unsigned int colour_next;       /* Per-node cache coloring */
 285         struct array_cache *shared;     /* shared per node */
 286         struct array_cache **alien;     /* on other nodes */
 287         unsigned long next_reap;        /* updated without locking */
 288         int free_touched;               /* updated without locking */
 289 #endif
 290
 291 #ifdef CONFIG_SLUB
 292         unsigned long nr_partial;
 293         struct list_head partial;
 294 #ifdef CONFIG_SLUB_DEBUG
 295         atomic_long_t nr_slabs;
 296         atomic_long_t total_objects;
 297         struct list_head full;
 298 #endif
 299 #endif
 300
 301 };
 302
 303 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 304 void slab_stop(struct seq_file *m, void *p);