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 static inline struct kmem_cache *cache_from_memcg(struct kmem_cache *s, int idx)
 164 {
 165         return s->memcg_params->memcg_caches[idx];
 166 }
 167
 168 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 169 {
 170         if (is_root_cache(s))
 171                 return s;
 172         return s->memcg_params->root_cache;
 173 }
 174 #else
 175 static inline bool is_root_cache(struct kmem_cache *s)
 176 {
 177         return true;
 178 }
 179
 180 static inline bool cache_match_memcg(struct kmem_cache *cachep,
 181                                      struct mem_cgroup *memcg)
 182 {
 183         return true;
 184 }
 185
 186 static inline void memcg_bind_pages(struct kmem_cache *s, int order)
 187 {
 188 }
 189
 190 static inline void memcg_release_pages(struct kmem_cache *s, int order)
 191 {
 192 }
 193
 194 static inline bool slab_equal_or_root(struct kmem_cache *s,
 195                                       struct kmem_cache *p)
 196 {
 197         return true;
 198 }
 199
 200 static inline const char *cache_name(struct kmem_cache *s)
 201 {
 202         return s->name;
 203 }
 204
 205 static inline struct kmem_cache *cache_from_memcg(struct kmem_cache *s, int idx)
 206 {
 207         return NULL;
 208 }
 209
 210 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 211 {
 212         return s;
 213 }
 214 #endif
 215
 216 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 217 {
 218         struct kmem_cache *cachep;
 219         struct page *page;
 220
 221         /*
 222          * When kmemcg is not being used, both assignments should return the
 223          * same value. but we don't want to pay the assignment price in that
 224          * case. If it is not compiled in, the compiler should be smart enough
 225          * to not do even the assignment. In that case, slab_equal_or_root
 226          * will also be a constant.
 227          */
 228         if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))
 229                 return s;
 230
 231         page = virt_to_head_page(x);
 232         cachep = page->slab_cache;
 233         if (slab_equal_or_root(cachep, s))
 234                 return cachep;
 235
 236         pr_err("%s: Wrong slab cache. %s but object is from %s\n",
 237                 __FUNCTION__, cachep->name, s->name);
 238         WARN_ON_ONCE(1);
 239         return s;
 240 }
 241 #endif
 242
 243
 244 /*
 245  * The slab lists for all objects.
 246  */
 247 struct kmem_cache_node {
 248         spinlock_t list_lock;
 249
 250 #ifdef CONFIG_SLAB
 251         struct list_head slabs_partial; /* partial list first, better asm code */
 252         struct list_head slabs_full;
 253         struct list_head slabs_free;
 254         unsigned long free_objects;
 255         unsigned int free_limit;
 256         unsigned int colour_next;       /* Per-node cache coloring */
 257         struct array_cache *shared;     /* shared per node */
 258         struct array_cache **alien;     /* on other nodes */
 259         unsigned long next_reap;        /* updated without locking */
 260         int free_touched;               /* updated without locking */
 261 #endif
 262
 263 #ifdef CONFIG_SLUB
 264         unsigned long nr_partial;
 265         struct list_head partial;
 266 #ifdef CONFIG_SLUB_DEBUG
 267         atomic_long_t nr_slabs;
 268         atomic_long_t total_objects;
 269         struct list_head full;
 270 #endif
 271 #endif
 272
 273 };
 274
 275 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 276 void slab_stop(struct seq_file *m, void *p);