/* memcontrol.h - Memory Controller
   *
   * Copyright IBM Corporation, 2007
   * Author Balbir Singh <balbir@linux.vnet.ibm.com>
   *
   * Copyright 2007 OpenVZ SWsoft Inc
   * Author: Pavel Emelianov <xemul@openvz.org>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   */
  
  #ifndef _LINUX_MEMCONTROL_H
  #define _LINUX_MEMCONTROL_H
  #include <linux/cgroup.h>
  #include <linux/vm_event_item.h>
  #include <linux/hardirq.h>
  #include <linux/jump_label.h>
  
  struct mem_cgroup;
  struct page_cgroup;
  struct page;
  struct mm_struct;
  struct kmem_cache;
  
  /*
   * The corresponding mem_cgroup_stat_names is defined in mm/memcontrol.c,
   * These two lists should keep in accord with each other.
   */
  enum mem_cgroup_stat_index {
  	/*
  	 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
  	 */
  	MEM_CGROUP_STAT_CACHE,		/* # of pages charged as cache */
  	MEM_CGROUP_STAT_RSS,		/* # of pages charged as anon rss */
  	MEM_CGROUP_STAT_RSS_HUGE,	/* # of pages charged as anon huge */
  	MEM_CGROUP_STAT_FILE_MAPPED,	/* # of pages charged as file rss */
  	MEM_CGROUP_STAT_WRITEBACK,	/* # of pages under writeback */
  	MEM_CGROUP_STAT_SWAP,		/* # of pages, swapped out */
  	MEM_CGROUP_STAT_NSTATS,
  };
  
  struct mem_cgroup_reclaim_cookie {
  	struct zone *zone;
  	int priority;
  	unsigned int generation;
  };
  
  #ifdef CONFIG_MEMCG
  /*
   * All "charge" functions with gfp_mask should use GFP_KERNEL or
   * (gfp_mask & GFP_RECLAIM_MASK). In current implementatin, memcg doesn't
   * alloc memory but reclaims memory from all available zones. So, "where I want
   * memory from" bits of gfp_mask has no meaning. So any bits of that field is
   * available but adding a rule is better. charge functions' gfp_mask should
   * be set to GFP_KERNEL or gfp_mask & GFP_RECLAIM_MASK for avoiding ambiguous
   * codes.
   * (Of course, if memcg does memory allocation in future, GFP_KERNEL is sane.)
   */
  
  extern int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm,
  				gfp_t gfp_mask);
  /* for swap handling */
  extern int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
  		struct page *page, gfp_t mask, struct mem_cgroup **memcgp);
  extern void mem_cgroup_commit_charge_swapin(struct page *page,
  					struct mem_cgroup *memcg);
  extern void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg);
  
  extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
  					gfp_t gfp_mask);
  
  struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *);
  struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *);
  
  /* For coalescing uncharge for reducing memcg' overhead*/
  extern void mem_cgroup_uncharge_start(void);
  extern void mem_cgroup_uncharge_end(void);
  
  extern void mem_cgroup_uncharge_page(struct page *page);
  extern void mem_cgroup_uncharge_cache_page(struct page *page);
  
  bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
  				  struct mem_cgroup *memcg);
  bool task_in_mem_cgroup(struct task_struct *task,
  			const struct mem_cgroup *memcg);
  
  extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
  extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
  extern struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm);
  
  extern struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);
  extern struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css);
  
  static inline
  bool mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *memcg)
  {
  	struct mem_cgroup *task_memcg;
  	bool match;
  
  	rcu_read_lock();
  	task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
  	match = __mem_cgroup_same_or_subtree(memcg, task_memcg);
  	rcu_read_unlock();
  	return match;
  }
  
  extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg);
  
  extern void
  mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
  			     struct mem_cgroup **memcgp);
  extern void mem_cgroup_end_migration(struct mem_cgroup *memcg,
  	struct page *oldpage, struct page *newpage, bool migration_ok);
  
  struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
  				   struct mem_cgroup *,
  				   struct mem_cgroup_reclaim_cookie *);
  void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
  
  /*
   * For memory reclaim.
   */
  int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec);
  int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
  unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list);
  void mem_cgroup_update_lru_size(struct lruvec *, enum lru_list, int);
  extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
  					struct task_struct *p);
  extern void mem_cgroup_replace_page_cache(struct page *oldpage,
  					struct page *newpage);
  
  static inline void mem_cgroup_oom_enable(void)
  {
  	WARN_ON(current->memcg_oom.may_oom);
  	current->memcg_oom.may_oom = 1;
  }
  
  static inline void mem_cgroup_oom_disable(void)
  {
  	WARN_ON(!current->memcg_oom.may_oom);
  	current->memcg_oom.may_oom = 0;
  }
  
  static inline bool task_in_memcg_oom(struct task_struct *p)
  {
  	return p->memcg_oom.memcg;
  }
  
  bool mem_cgroup_oom_synchronize(bool wait);
  
  #ifdef CONFIG_MEMCG_SWAP
  extern int do_swap_account;
  #endif
  
  static inline bool mem_cgroup_disabled(void)
  {
  	if (mem_cgroup_subsys.disabled)
  		return true;
  	return false;
  }
  
  void __mem_cgroup_begin_update_page_stat(struct page *page, bool *locked,
  					 unsigned long *flags);
  
  extern atomic_t memcg_moving;
  
  static inline void mem_cgroup_begin_update_page_stat(struct page *page,
  					bool *locked, unsigned long *flags)
  {
  	if (mem_cgroup_disabled())
  		return;
  	rcu_read_lock();
  	*locked = false;
  	if (atomic_read(&memcg_moving))
  		__mem_cgroup_begin_update_page_stat(page, locked, flags);
  }
  
  void __mem_cgroup_end_update_page_stat(struct page *page,
  				unsigned long *flags);
  static inline void mem_cgroup_end_update_page_stat(struct page *page,
  					bool *locked, unsigned long *flags)
  {
  	if (mem_cgroup_disabled())
  		return;
  	if (*locked)
  		__mem_cgroup_end_update_page_stat(page, flags);
  	rcu_read_unlock();
  }
  
  void mem_cgroup_update_page_stat(struct page *page,
  				 enum mem_cgroup_stat_index idx,
  				 int val);
  
  static inline void mem_cgroup_inc_page_stat(struct page *page,
  					    enum mem_cgroup_stat_index idx)
  {
  	mem_cgroup_update_page_stat(page, idx, 1);
  }
  
  static inline void mem_cgroup_dec_page_stat(struct page *page,
  					    enum mem_cgroup_stat_index idx)
  {
  	mem_cgroup_update_page_stat(page, idx, -1);
  }
  
  unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
  						gfp_t gfp_mask,
  						unsigned long *total_scanned);
  
  void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
  static inline void mem_cgroup_count_vm_event(struct mm_struct *mm,
  					     enum vm_event_item idx)
  {
  	if (mem_cgroup_disabled())
  		return;
  	__mem_cgroup_count_vm_event(mm, idx);
  }
  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  void mem_cgroup_split_huge_fixup(struct page *head);
  #endif
  
  #ifdef CONFIG_DEBUG_VM
  bool mem_cgroup_bad_page_check(struct page *page);
  void mem_cgroup_print_bad_page(struct page *page);
  #endif
  #else /* CONFIG_MEMCG */
  struct mem_cgroup;
  
  static inline int mem_cgroup_newpage_charge(struct page *page,
  					struct mm_struct *mm, gfp_t gfp_mask)
  {
  	return 0;
  }
  
  static inline int mem_cgroup_cache_charge(struct page *page,
  					struct mm_struct *mm, gfp_t gfp_mask)
  {
  	return 0;
  }
  
  static inline int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
  		struct page *page, gfp_t gfp_mask, struct mem_cgroup **memcgp)
  {
  	return 0;
  }
  
  static inline void mem_cgroup_commit_charge_swapin(struct page *page,
  					  struct mem_cgroup *memcg)
  {
  }
  
  static inline void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
  {
  }
  
  static inline void mem_cgroup_uncharge_start(void)
  {
  }
  
  static inline void mem_cgroup_uncharge_end(void)
  {
  }
  
  static inline void mem_cgroup_uncharge_page(struct page *page)
  {
  }
  
  static inline void mem_cgroup_uncharge_cache_page(struct page *page)
  {
  }
  
  static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
  						    struct mem_cgroup *memcg)
  {
  	return &zone->lruvec;
  }
  
  static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
  						    struct zone *zone)
  {
  	return &zone->lruvec;
  }
  
  static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
  {
  	return NULL;
  }
  
  static inline struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
  {
  	return NULL;
  }
  
  static inline bool mm_match_cgroup(struct mm_struct *mm,
  		struct mem_cgroup *memcg)
  {
  	return true;
  }
  
  static inline bool task_in_mem_cgroup(struct task_struct *task,
  				      const struct mem_cgroup *memcg)
  {
  	return true;
  }
  
  static inline struct cgroup_subsys_state
  		*mem_cgroup_css(struct mem_cgroup *memcg)
  {
  	return NULL;
  }
  
  static inline void
  mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
  			     struct mem_cgroup **memcgp)
  {
  }
  
  static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg,
  		struct page *oldpage, struct page *newpage, bool migration_ok)
  {
  }
  
  static inline struct mem_cgroup *
  mem_cgroup_iter(struct mem_cgroup *root,
  		struct mem_cgroup *prev,
  		struct mem_cgroup_reclaim_cookie *reclaim)
  {
  	return NULL;
  }
  
  static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
  					 struct mem_cgroup *prev)
  {
  }
  
  static inline bool mem_cgroup_disabled(void)
  {
  	return true;
  }
  
  static inline int
  mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
  {
  	return 1;
  }
  
  static inline unsigned long
  mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
  {
  	return 0;
  }
  
  static inline void
  mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
  			      int increment)
  {
  }
  
  static inline void
  mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
  {
  }
  
  static inline void mem_cgroup_begin_update_page_stat(struct page *page,
  					bool *locked, unsigned long *flags)
  {
  }
  
  static inline void mem_cgroup_end_update_page_stat(struct page *page,
  					bool *locked, unsigned long *flags)
  {
  }
  
  static inline void mem_cgroup_oom_enable(void)
  {
  }
  
  static inline void mem_cgroup_oom_disable(void)
  {
  }
  
  static inline bool task_in_memcg_oom(struct task_struct *p)
  {
  	return false;
  }
  
  static inline bool mem_cgroup_oom_synchronize(bool wait)
  {
  	return false;
  }
  
  static inline void mem_cgroup_inc_page_stat(struct page *page,
  					    enum mem_cgroup_stat_index idx)
  {
  }
  
  static inline void mem_cgroup_dec_page_stat(struct page *page,
  					    enum mem_cgroup_stat_index idx)
  {
  }
  
  static inline
  unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
  					    gfp_t gfp_mask,
  					    unsigned long *total_scanned)
  {
  	return 0;
  }
  
  static inline void mem_cgroup_split_huge_fixup(struct page *head)
  {
  }
  
  static inline
  void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
  {
  }
  static inline void mem_cgroup_replace_page_cache(struct page *oldpage,
  				struct page *newpage)
  {
  }
  #endif /* CONFIG_MEMCG */
  
  #if !defined(CONFIG_MEMCG) || !defined(CONFIG_DEBUG_VM)
  static inline bool
  mem_cgroup_bad_page_check(struct page *page)
  {
  	return false;
  }
  
  static inline void
  mem_cgroup_print_bad_page(struct page *page)
  {
  }
  #endif
  
  enum {
  	UNDER_LIMIT,
  	SOFT_LIMIT,
  	OVER_LIMIT,
  };
  
  struct sock;
  #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
  void sock_update_memcg(struct sock *sk);
  void sock_release_memcg(struct sock *sk);
  #else
  static inline void sock_update_memcg(struct sock *sk)
  {
  }
  static inline void sock_release_memcg(struct sock *sk)
  {
  }
  #endif /* CONFIG_INET && CONFIG_MEMCG_KMEM */
  
  #ifdef CONFIG_MEMCG_KMEM
  extern struct static_key memcg_kmem_enabled_key;
  
  extern int memcg_limited_groups_array_size;
  
  /*
   * Helper macro to loop through all memcg-specific caches. Callers must still
   * check if the cache is valid (it is either valid or NULL).
   * the slab_mutex must be held when looping through those caches
   */
  #define for_each_memcg_cache_index(_idx)	\
  	for ((_idx) = 0; (_idx) < memcg_limited_groups_array_size; (_idx)++)
  
  static inline bool memcg_kmem_enabled(void)
  {
  	return static_key_false(&memcg_kmem_enabled_key);
  }
  
  /*
   * In general, we'll do everything in our power to not incur in any overhead
   * for non-memcg users for the kmem functions. Not even a function call, if we
   * can avoid it.
   *
   * Therefore, we'll inline all those functions so that in the best case, we'll
   * see that kmemcg is off for everybody and proceed quickly.  If it is on,
   * we'll still do most of the flag checking inline. We check a lot of
   * conditions, but because they are pretty simple, they are expected to be
   * fast.
   */
  bool __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg,
  					int order);
  void __memcg_kmem_commit_charge(struct page *page,
  				       struct mem_cgroup *memcg, int order);
  void __memcg_kmem_uncharge_pages(struct page *page, int order);
  
  int memcg_cache_id(struct mem_cgroup *memcg);
  int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
  			     struct kmem_cache *root_cache);
  void memcg_free_cache_params(struct kmem_cache *s);
  void memcg_register_cache(struct kmem_cache *s);
  void memcg_unregister_cache(struct kmem_cache *s);
  
  int memcg_update_cache_size(struct kmem_cache *s, int num_groups);
  void memcg_update_array_size(int num_groups);
  
  struct kmem_cache *
  __memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp);
  
  void mem_cgroup_destroy_cache(struct kmem_cache *cachep);
  void kmem_cache_destroy_memcg_children(struct kmem_cache *s);
  
  /**
   * memcg_kmem_newpage_charge: verify if a new kmem allocation is allowed.
   * @gfp: the gfp allocation flags.
   * @memcg: a pointer to the memcg this was charged against.
   * @order: allocation order.
   *
   * returns true if the memcg where the current task belongs can hold this
   * allocation.
   *
   * We return true automatically if this allocation is not to be accounted to
   * any memcg.
   */
  static inline bool
  memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)
  {
  	if (!memcg_kmem_enabled())
  		return true;
  
  	/*
  	 * __GFP_NOFAIL allocations will move on even if charging is not
  	 * possible. Therefore we don't even try, and have this allocation
  	 * unaccounted. We could in theory charge it with
  	 * res_counter_charge_nofail, but we hope those allocations are rare,
  	 * and won't be worth the trouble.
  	 */
  	if (!(gfp & __GFP_KMEMCG) || (gfp & __GFP_NOFAIL))
  		return true;
  	if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
  		return true;
  
  	/* If the test is dying, just let it go. */
  	if (unlikely(fatal_signal_pending(current)))
  		return true;
  
  	return __memcg_kmem_newpage_charge(gfp, memcg, order);
  }
  
  /**
   * memcg_kmem_uncharge_pages: uncharge pages from memcg
   * @page: pointer to struct page being freed
   * @order: allocation order.
   *
   * there is no need to specify memcg here, since it is embedded in page_cgroup
   */
  static inline void
  memcg_kmem_uncharge_pages(struct page *page, int order)
  {
  	if (memcg_kmem_enabled())
  		__memcg_kmem_uncharge_pages(page, order);
  }
  
  /**
   * memcg_kmem_commit_charge: embeds correct memcg in a page
   * @page: pointer to struct page recently allocated
   * @memcg: the memcg structure we charged against
   * @order: allocation order.
   *
   * Needs to be called after memcg_kmem_newpage_charge, regardless of success or
   * failure of the allocation. if @page is NULL, this function will revert the
   * charges. Otherwise, it will commit the memcg given by @memcg to the
   * corresponding page_cgroup.
   */
  static inline void
  memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order)
  {
  	if (memcg_kmem_enabled() && memcg)
  		__memcg_kmem_commit_charge(page, memcg, order);
  }
  
  /**
   * memcg_kmem_get_cache: selects the correct per-memcg cache for allocation
   * @cachep: the original global kmem cache
   * @gfp: allocation flags.
   *
   * This function assumes that the task allocating, which determines the memcg
   * in the page allocator, belongs to the same cgroup throughout the whole
   * process.  Misacounting can happen if the task calls memcg_kmem_get_cache()
   * while belonging to a cgroup, and later on changes. This is considered
   * acceptable, and should only happen upon task migration.
   *
   * Before the cache is created by the memcg core, there is also a possible
   * imbalance: the task belongs to a memcg, but the cache being allocated from
   * is the global cache, since the child cache is not yet guaranteed to be
   * ready. This case is also fine, since in this case the GFP_KMEMCG will not be
   * passed and the page allocator will not attempt any cgroup accounting.
   */
  static __always_inline struct kmem_cache *
  memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
  {
  	if (!memcg_kmem_enabled())
  		return cachep;
  	if (gfp & __GFP_NOFAIL)
  		return cachep;
  	if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
  		return cachep;
  	if (unlikely(fatal_signal_pending(current)))
  		return cachep;
  
  	return __memcg_kmem_get_cache(cachep, gfp);
  }
  #else
  #define for_each_memcg_cache_index(_idx)	\
  	for (; NULL; )
  
  static inline bool memcg_kmem_enabled(void)
  {
  	return false;
  }
  
  static inline bool
  memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)
  {
  	return true;
  }
  
  static inline void memcg_kmem_uncharge_pages(struct page *page, int order)
  {
  }
  
  static inline void
  memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order)
  {
  }
  
  static inline int memcg_cache_id(struct mem_cgroup *memcg)
  {
  	return -1;
  }
  
  static inline int memcg_alloc_cache_params(struct mem_cgroup *memcg,
  		struct kmem_cache *s, struct kmem_cache *root_cache)
  {
  	return 0;
  }
  
  static inline void memcg_free_cache_params(struct kmem_cache *s)
  {
  }
  
  static inline void memcg_register_cache(struct kmem_cache *s)
  {
  }
  
  static inline void memcg_unregister_cache(struct kmem_cache *s)
  {
  }
  
  static inline struct kmem_cache *
  memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
  {
  	return cachep;
  }
  
  static inline void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
  {
  }
  #endif /* CONFIG_MEMCG_KMEM */
  #endif /* _LINUX_MEMCONTROL_H */