#ifndef MM_SLAB_H
  #define MM_SLAB_H
  /*
   * Internal slab definitions
   */
  
  /*
   * State of the slab allocator.
   *
   * This is used to describe the states of the allocator during bootup.
   * Allocators use this to gradually bootstrap themselves. Most allocators
   * have the problem that the structures used for managing slab caches are
   * allocated from slab caches themselves.
   */
  enum slab_state {
  	DOWN,			/* No slab functionality yet */
  	PARTIAL,		/* SLUB: kmem_cache_node available */
  	PARTIAL_ARRAYCACHE,	/* SLAB: kmalloc size for arraycache available */
  	PARTIAL_NODE,		/* SLAB: kmalloc size for node struct available */
  	UP,			/* Slab caches usable but not all extras yet */
  	FULL			/* Everything is working */
  };
  
  extern enum slab_state slab_state;
  
  /* The slab cache mutex protects the management structures during changes */
  extern struct mutex slab_mutex;
  
  /* The list of all slab caches on the system */
  extern struct list_head slab_caches;
  
  /* The slab cache that manages slab cache information */
  extern struct kmem_cache *kmem_cache;
  
  unsigned long calculate_alignment(unsigned long flags,
  		unsigned long align, unsigned long size);
  
  #ifndef CONFIG_SLOB
  /* Kmalloc array related functions */
  void create_kmalloc_caches(unsigned long);
  
  /* Find the kmalloc slab corresponding for a certain size */
  struct kmem_cache *kmalloc_slab(size_t, gfp_t);
  #endif
  
  
  /* Functions provided by the slab allocators */
  extern int __kmem_cache_create(struct kmem_cache *, unsigned long flags);
  
  extern struct kmem_cache *create_kmalloc_cache(const char *name, size_t size,
  			unsigned long flags);
  extern void create_boot_cache(struct kmem_cache *, const char *name,
  			size_t size, unsigned long flags);
  
  struct mem_cgroup;
  #ifdef CONFIG_SLUB
  struct kmem_cache *
  __kmem_cache_alias(struct mem_cgroup *memcg, const char *name, size_t size,
  		   size_t align, unsigned long flags, void (*ctor)(void *));
  #else
  static inline struct kmem_cache *
  __kmem_cache_alias(struct mem_cgroup *memcg, const char *name, size_t size,
  		   size_t align, unsigned long flags, void (*ctor)(void *))
  { return NULL; }
  #endif
  
  
  /* Legal flag mask for kmem_cache_create(), for various configurations */
  #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
  			 SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS )
  
  #if defined(CONFIG_DEBUG_SLAB)
  #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
  #elif defined(CONFIG_SLUB_DEBUG)
  #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
  			  SLAB_TRACE | SLAB_DEBUG_FREE)
  #else
  #define SLAB_DEBUG_FLAGS (0)
  #endif
  
  #if defined(CONFIG_SLAB)
  #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
  			  SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | SLAB_NOTRACK)
  #elif defined(CONFIG_SLUB)
  #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
  			  SLAB_TEMPORARY | SLAB_NOTRACK)
  #else
  #define SLAB_CACHE_FLAGS (0)
  #endif
  
  #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
  
  int __kmem_cache_shutdown(struct kmem_cache *);
  
  struct seq_file;
  struct file;
  
  struct slabinfo {
  	unsigned long active_objs;
  	unsigned long num_objs;
  	unsigned long active_slabs;
  	unsigned long num_slabs;
  	unsigned long shared_avail;
  	unsigned int limit;
  	unsigned int batchcount;
  	unsigned int shared;
  	unsigned int objects_per_slab;
  	unsigned int cache_order;
  };
  
  void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
  void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
  ssize_t slabinfo_write(struct file *file, const char __user *buffer,
  		       size_t count, loff_t *ppos);
  
  #ifdef CONFIG_MEMCG_KMEM
  static inline bool is_root_cache(struct kmem_cache *s)
  {
  	return !s->memcg_params || s->memcg_params->is_root_cache;
  }
  
  static inline bool cache_match_memcg(struct kmem_cache *cachep,
  				     struct mem_cgroup *memcg)
  {
  	return (is_root_cache(cachep) && !memcg) ||
  				(cachep->memcg_params->memcg == memcg);
  }
  
  static inline void memcg_bind_pages(struct kmem_cache *s, int order)
  {
  	if (!is_root_cache(s))
  		atomic_add(1 << order, &s->memcg_params->nr_pages);
  }
  
  static inline void memcg_release_pages(struct kmem_cache *s, int order)
  {
  	if (is_root_cache(s))
  		return;
  
  	if (atomic_sub_and_test((1 << order), &s->memcg_params->nr_pages))
  		mem_cgroup_destroy_cache(s);
  }
  
  static inline bool slab_equal_or_root(struct kmem_cache *s,
  					struct kmem_cache *p)
  {
  	return (p == s) ||
  		(s->memcg_params && (p == s->memcg_params->root_cache));
  }
  
  /*
   * We use suffixes to the name in memcg because we can't have caches
   * created in the system with the same name. But when we print them
   * locally, better refer to them with the base name
   */
  static inline const char *cache_name(struct kmem_cache *s)
  {
  	if (!is_root_cache(s))
  		return s->memcg_params->root_cache->name;
  	return s->name;
  }
  
  /*
   * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
   * That said the caller must assure the memcg's cache won't go away. Since once
   * created a memcg's cache is destroyed only along with the root cache, it is
   * true if we are going to allocate from the cache or hold a reference to the
   * root cache by other means. Otherwise, we should hold either the slab_mutex
   * or the memcg's slab_caches_mutex while calling this function and accessing
   * the returned value.
   */
  static inline struct kmem_cache *
  cache_from_memcg_idx(struct kmem_cache *s, int idx)
  {
  	struct kmem_cache *cachep;
  	struct memcg_cache_params *params;
  
  	if (!s->memcg_params)
  		return NULL;
  
  	rcu_read_lock();
  	params = rcu_dereference(s->memcg_params);
  	cachep = params->memcg_caches[idx];
  	rcu_read_unlock();
  
  	/*
  	 * Make sure we will access the up-to-date value. The code updating
  	 * memcg_caches issues a write barrier to match this (see
  	 * memcg_register_cache()).
  	 */
  	smp_read_barrier_depends();
  	return cachep;
  }
  
  static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
  {
  	if (is_root_cache(s))
  		return s;
  	return s->memcg_params->root_cache;
  }
  #else
  static inline bool is_root_cache(struct kmem_cache *s)
  {
  	return true;
  }
  
  static inline bool cache_match_memcg(struct kmem_cache *cachep,
  				     struct mem_cgroup *memcg)
  {
  	return true;
  }
  
  static inline void memcg_bind_pages(struct kmem_cache *s, int order)
  {
  }
  
  static inline void memcg_release_pages(struct kmem_cache *s, int order)
  {
  }
  
  static inline bool slab_equal_or_root(struct kmem_cache *s,
  				      struct kmem_cache *p)
  {
  	return true;
  }
  
  static inline const char *cache_name(struct kmem_cache *s)
  {
  	return s->name;
  }
  
  static inline struct kmem_cache *
  cache_from_memcg_idx(struct kmem_cache *s, int idx)
  {
  	return NULL;
  }
  
  static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
  {
  	return s;
  }
  #endif
  
  static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
  {
  	struct kmem_cache *cachep;
  	struct page *page;
  
  	/*
  	 * When kmemcg is not being used, both assignments should return the
  	 * same value. but we don't want to pay the assignment price in that
  	 * case. If it is not compiled in, the compiler should be smart enough
  	 * to not do even the assignment. In that case, slab_equal_or_root
  	 * will also be a constant.
  	 */
  	if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE))
  		return s;
  
  	page = virt_to_head_page(x);
  	cachep = page->slab_cache;
  	if (slab_equal_or_root(cachep, s))
  		return cachep;
  
  	pr_err("%s: Wrong slab cache. %s but object is from %s
  ",
  		__FUNCTION__, cachep->name, s->name);
  	WARN_ON_ONCE(1);
  	return s;
  }
  #endif
  
  
  /*
   * The slab lists for all objects.
   */
  struct kmem_cache_node {
  	spinlock_t list_lock;
  
  #ifdef CONFIG_SLAB
  	struct list_head slabs_partial;	/* partial list first, better asm code */
  	struct list_head slabs_full;
  	struct list_head slabs_free;
  	unsigned long free_objects;
  	unsigned int free_limit;
  	unsigned int colour_next;	/* Per-node cache coloring */
  	struct array_cache *shared;	/* shared per node */
  	struct array_cache **alien;	/* on other nodes */
  	unsigned long next_reap;	/* updated without locking */
  	int free_touched;		/* updated without locking */
  #endif
  
  #ifdef CONFIG_SLUB
  	unsigned long nr_partial;
  	struct list_head partial;
  #ifdef CONFIG_SLUB_DEBUG
  	atomic_long_t nr_slabs;
  	atomic_long_t total_objects;
  	struct list_head full;
  #endif
  #endif
  
  };
  
  void *slab_next(struct seq_file *m, void *p, loff_t *pos);
  void slab_stop(struct seq_file *m, void *p);