/* 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>

  #include <linux/page_counter.h>
  #include <linux/vmpressure.h>
  #include <linux/eventfd.h>

  #include <linux/mm.h>
  #include <linux/vmstat.h>

  #include <linux/writeback.h>

  #include <linux/page-flags.h>

  struct mem_cgroup;

  struct page;
  struct mm_struct;

  struct kmem_cache;

  /* Cgroup-specific page state, on top of universal node page state */
  enum memcg_stat_item {
  	MEMCG_CACHE = NR_VM_NODE_STAT_ITEMS,
  	MEMCG_RSS,
  	MEMCG_RSS_HUGE,
  	MEMCG_SWAP,
  	MEMCG_SOCK,
  	/* XXX: why are these zone and not node counters? */
  	MEMCG_KERNEL_STACK_KB,

  	MEMCG_NR_STAT,

  };

  /* Cgroup-specific events, on top of universal VM events */
  enum memcg_event_item {
  	MEMCG_LOW = NR_VM_EVENT_ITEMS,
  	MEMCG_HIGH,
  	MEMCG_MAX,
  	MEMCG_OOM,
  	MEMCG_NR_EVENTS,
  };

  struct mem_cgroup_reclaim_cookie {

  	pg_data_t *pgdat;

  	int priority;
  	unsigned int generation;
  };

  #ifdef CONFIG_MEMCG
  
  #define MEM_CGROUP_ID_SHIFT	16
  #define MEM_CGROUP_ID_MAX	USHRT_MAX
  
  struct mem_cgroup_id {
  	int id;
  	atomic_t ref;
  };

  /*
   * Per memcg event counter is incremented at every pagein/pageout. With THP,
   * it will be incremated by the number of pages. This counter is used for
   * for trigger some periodic events. This is straightforward and better
   * than using jiffies etc. to handle periodic memcg event.
   */
  enum mem_cgroup_events_target {
  	MEM_CGROUP_TARGET_THRESH,
  	MEM_CGROUP_TARGET_SOFTLIMIT,
  	MEM_CGROUP_TARGET_NUMAINFO,
  	MEM_CGROUP_NTARGETS,
  };

  struct mem_cgroup_stat_cpu {

  	long count[MEMCG_NR_STAT];

  	unsigned long events[MEMCG_NR_EVENTS];
  	unsigned long nr_page_events;
  	unsigned long targets[MEM_CGROUP_NTARGETS];
  };
  
  struct mem_cgroup_reclaim_iter {
  	struct mem_cgroup *position;
  	/* scan generation, increased every round-trip */
  	unsigned int generation;
  };

  struct lruvec_stat {
  	long count[NR_VM_NODE_STAT_ITEMS];
  };

  /*
   * per-zone information in memory controller.
   */

  struct mem_cgroup_per_node {

  	struct lruvec		lruvec;

  	struct lruvec_stat __percpu *lruvec_stat;

  	unsigned long		lru_zone_size[MAX_NR_ZONES][NR_LRU_LISTS];

  
  	struct mem_cgroup_reclaim_iter	iter[DEF_PRIORITY + 1];
  
  	struct rb_node		tree_node;	/* RB tree node */
  	unsigned long		usage_in_excess;/* Set to the value by which */
  						/* the soft limit is exceeded*/
  	bool			on_tree;
  	struct mem_cgroup	*memcg;		/* Back pointer, we cannot */
  						/* use container_of	   */
  };

  struct mem_cgroup_threshold {
  	struct eventfd_ctx *eventfd;
  	unsigned long threshold;
  };
  
  /* For threshold */
  struct mem_cgroup_threshold_ary {
  	/* An array index points to threshold just below or equal to usage. */
  	int current_threshold;
  	/* Size of entries[] */
  	unsigned int size;
  	/* Array of thresholds */
  	struct mem_cgroup_threshold entries[0];
  };
  
  struct mem_cgroup_thresholds {
  	/* Primary thresholds array */
  	struct mem_cgroup_threshold_ary *primary;
  	/*
  	 * Spare threshold array.
  	 * This is needed to make mem_cgroup_unregister_event() "never fail".
  	 * It must be able to store at least primary->size - 1 entries.
  	 */
  	struct mem_cgroup_threshold_ary *spare;
  };

  enum memcg_kmem_state {
  	KMEM_NONE,
  	KMEM_ALLOCATED,
  	KMEM_ONLINE,
  };

  /*
   * The memory controller data structure. The memory controller controls both
   * page cache and RSS per cgroup. We would eventually like to provide
   * statistics based on the statistics developed by Rik Van Riel for clock-pro,
   * to help the administrator determine what knobs to tune.
   */
  struct mem_cgroup {
  	struct cgroup_subsys_state css;

  	/* Private memcg ID. Used to ID objects that outlive the cgroup */
  	struct mem_cgroup_id id;

  	/* Accounted resources */
  	struct page_counter memory;

  	struct page_counter swap;

  
  	/* Legacy consumer-oriented counters */

  	struct page_counter memsw;
  	struct page_counter kmem;

  	struct page_counter tcpmem;

  
  	/* Normal memory consumption range */
  	unsigned long low;
  	unsigned long high;

  	/* Range enforcement for interrupt charges */
  	struct work_struct high_work;

  	unsigned long soft_limit;
  
  	/* vmpressure notifications */
  	struct vmpressure vmpressure;

  	/*
  	 * Should the accounting and control be hierarchical, per subtree?
  	 */
  	bool use_hierarchy;
  
  	/* protected by memcg_oom_lock */
  	bool		oom_lock;
  	int		under_oom;
  
  	int	swappiness;
  	/* OOM-Killer disable */
  	int		oom_kill_disable;

  	/* handle for "memory.events" */
  	struct cgroup_file events_file;

  	/* protect arrays of thresholds */
  	struct mutex thresholds_lock;
  
  	/* thresholds for memory usage. RCU-protected */
  	struct mem_cgroup_thresholds thresholds;
  
  	/* thresholds for mem+swap usage. RCU-protected */
  	struct mem_cgroup_thresholds memsw_thresholds;
  
  	/* For oom notifier event fd */
  	struct list_head oom_notify;
  
  	/*
  	 * Should we move charges of a task when a task is moved into this
  	 * mem_cgroup ? And what type of charges should we move ?
  	 */
  	unsigned long move_charge_at_immigrate;
  	/*
  	 * set > 0 if pages under this cgroup are moving to other cgroup.
  	 */
  	atomic_t		moving_account;
  	/* taken only while moving_account > 0 */
  	spinlock_t		move_lock;
  	struct task_struct	*move_lock_task;
  	unsigned long		move_lock_flags;
  	/*
  	 * percpu counter.
  	 */
  	struct mem_cgroup_stat_cpu __percpu *stat;

  	unsigned long		socket_pressure;
  
  	/* Legacy tcp memory accounting */

  	bool			tcpmem_active;
  	int			tcpmem_pressure;

  #ifndef CONFIG_SLOB

          /* Index in the kmem_cache->memcg_params.memcg_caches array */
  	int kmemcg_id;

  	enum memcg_kmem_state kmem_state;

  	struct list_head kmem_caches;

  #endif
  
  	int last_scanned_node;
  #if MAX_NUMNODES > 1
  	nodemask_t	scan_nodes;
  	atomic_t	numainfo_events;
  	atomic_t	numainfo_updating;
  #endif
  
  #ifdef CONFIG_CGROUP_WRITEBACK
  	struct list_head cgwb_list;
  	struct wb_domain cgwb_domain;
  #endif
  
  	/* List of events which userspace want to receive */
  	struct list_head event_list;
  	spinlock_t event_list_lock;
  
  	struct mem_cgroup_per_node *nodeinfo[0];
  	/* WARNING: nodeinfo must be the last member here */
  };

  
  extern struct mem_cgroup *root_mem_cgroup;

  static inline bool mem_cgroup_disabled(void)
  {
  	return !cgroup_subsys_enabled(memory_cgrp_subsys);
  }

  static inline void mem_cgroup_event(struct mem_cgroup *memcg,

  				    enum memcg_event_item event)

  {

  	this_cpu_inc(memcg->stat->events[event]);

  	cgroup_file_notify(&memcg->events_file);

  }

  
  bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg);

  int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,

  			  gfp_t gfp_mask, struct mem_cgroup **memcgp,
  			  bool compound);

  void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,

  			      bool lrucare, bool compound);
  void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
  		bool compound);

  void mem_cgroup_uncharge(struct page *page);

  void mem_cgroup_uncharge_list(struct list_head *page_list);

  void mem_cgroup_migrate(struct page *oldpage, struct page *newpage);

  static struct mem_cgroup_per_node *
  mem_cgroup_nodeinfo(struct mem_cgroup *memcg, int nid)

  {

  	return memcg->nodeinfo[nid];

  }
  
  /**

   * mem_cgroup_lruvec - get the lru list vector for a node or a memcg zone
   * @node: node of the wanted lruvec

   * @memcg: memcg of the wanted lruvec
   *

   * Returns the lru list vector holding pages for a given @node or a given
   * @memcg and @zone. This can be the node lruvec, if the memory controller

   * is disabled.
   */

  static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,

  				struct mem_cgroup *memcg)

  {

  	struct mem_cgroup_per_node *mz;

  	struct lruvec *lruvec;
  
  	if (mem_cgroup_disabled()) {

  		lruvec = node_lruvec(pgdat);

  		goto out;
  	}

  	mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id);

  	lruvec = &mz->lruvec;
  out:
  	/*
  	 * Since a node can be onlined after the mem_cgroup was created,

  	 * we have to be prepared to initialize lruvec->pgdat here;

  	 * and if offlined then reonlined, we need to reinitialize it.
  	 */

  	if (unlikely(lruvec->pgdat != pgdat))
  		lruvec->pgdat = pgdat;

  	return lruvec;
  }

  struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);

  bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg);

  struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);

  static inline
  struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
  	return css ? container_of(css, struct mem_cgroup, css) : NULL;
  }

  #define mem_cgroup_from_counter(counter, member)	\
  	container_of(counter, struct mem_cgroup, member)

  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 *);

  int mem_cgroup_scan_tasks(struct mem_cgroup *,
  			  int (*)(struct task_struct *, void *), void *);

  static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
  {
  	if (mem_cgroup_disabled())
  		return 0;

  	return memcg->id.id;

  }

  struct mem_cgroup *mem_cgroup_from_id(unsigned short id);

  static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
  {
  	struct mem_cgroup_per_node *mz;
  
  	if (mem_cgroup_disabled())
  		return NULL;
  
  	mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
  	return mz->memcg;
  }

  /**
   * parent_mem_cgroup - find the accounting parent of a memcg
   * @memcg: memcg whose parent to find
   *
   * Returns the parent memcg, or NULL if this is the root or the memory
   * controller is in legacy no-hierarchy mode.
   */
  static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
  {
  	if (!memcg->memory.parent)
  		return NULL;
  	return mem_cgroup_from_counter(memcg->memory.parent, memory);
  }

  static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg,
  			      struct mem_cgroup *root)
  {
  	if (root == memcg)
  		return true;
  	if (!root->use_hierarchy)
  		return false;
  	return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup);
  }

  static inline bool mm_match_cgroup(struct mm_struct *mm,
  				   struct mem_cgroup *memcg)

  {

  	struct mem_cgroup *task_memcg;

  	bool match = false;

  	rcu_read_lock();

  	task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));

  	if (task_memcg)

  		match = mem_cgroup_is_descendant(task_memcg, memcg);

  	rcu_read_unlock();

  	return match;

  }

  struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page);

  ino_t page_cgroup_ino(struct page *page);

  static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
  {
  	if (mem_cgroup_disabled())
  		return true;
  	return !!(memcg->css.flags & CSS_ONLINE);
  }

  /*
   * For memory reclaim.
   */

  int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);

  
  void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,

  		int zid, int nr_pages);

  unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
  					   int nid, unsigned int lru_mask);

  static inline
  unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
  {

  	struct mem_cgroup_per_node *mz;

  	unsigned long nr_pages = 0;
  	int zid;

  	mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);

  	for (zid = 0; zid < MAX_NR_ZONES; zid++)
  		nr_pages += mz->lru_zone_size[zid][lru];
  	return nr_pages;
  }
  
  static inline
  unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
  		enum lru_list lru, int zone_idx)
  {
  	struct mem_cgroup_per_node *mz;
  
  	mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
  	return mz->lru_zone_size[zone_idx][lru];

  }

  void mem_cgroup_handle_over_high(void);

  unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg);

  void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
  				struct task_struct *p);

  static inline void mem_cgroup_oom_enable(void)

  {

  	WARN_ON(current->memcg_may_oom);
  	current->memcg_may_oom = 1;

  }

  static inline void mem_cgroup_oom_disable(void)

  {

  	WARN_ON(!current->memcg_may_oom);
  	current->memcg_may_oom = 0;

  }

  static inline bool task_in_memcg_oom(struct task_struct *p)
  {

  	return p->memcg_in_oom;

  }

  bool mem_cgroup_oom_synchronize(bool wait);

  #ifdef CONFIG_MEMCG_SWAP

  extern int do_swap_account;
  #endif

  struct mem_cgroup *lock_page_memcg(struct page *page);
  void __unlock_page_memcg(struct mem_cgroup *memcg);

  void unlock_page_memcg(struct page *page);

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline unsigned long memcg_page_state(struct mem_cgroup *memcg,

  					     int idx)

  {
  	long val = 0;
  	int cpu;
  
  	for_each_possible_cpu(cpu)
  		val += per_cpu(memcg->stat->count[idx], cpu);
  
  	if (val < 0)
  		val = 0;
  
  	return val;
  }

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void __mod_memcg_state(struct mem_cgroup *memcg,

  				     int idx, int val)

  {
  	if (!mem_cgroup_disabled())

  		__this_cpu_add(memcg->stat->count[idx], val);

  }

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void mod_memcg_state(struct mem_cgroup *memcg,

  				   int idx, int val)

  {

  	if (!mem_cgroup_disabled())
  		this_cpu_add(memcg->stat->count[idx], val);

  }

  /**

   * mod_memcg_page_state - update page state statistics

   * @page: the page

   * @idx: page state item to account
   * @val: number of pages (positive or negative)
   *

   * The @page must be locked or the caller must use lock_page_memcg()
   * to prevent double accounting when the page is concurrently being
   * moved to another memcg:

   *

   *   lock_page(page) or lock_page_memcg(page)

   *   if (TestClearPageState(page))

   *     mod_memcg_page_state(page, state, -1);

   *   unlock_page(page) or unlock_page_memcg(page)

   *
   * Kernel pages are an exception to this, since they'll never move.

   */

  static inline void __mod_memcg_page_state(struct page *page,

  					  int idx, int val)

  {
  	if (page->mem_cgroup)
  		__mod_memcg_state(page->mem_cgroup, idx, val);
  }

  static inline void mod_memcg_page_state(struct page *page,

  					int idx, int val)

  {

  	if (page->mem_cgroup)

  		mod_memcg_state(page->mem_cgroup, idx, val);

  }

  static inline unsigned long lruvec_page_state(struct lruvec *lruvec,
  					      enum node_stat_item idx)

  {

  	struct mem_cgroup_per_node *pn;
  	long val = 0;
  	int cpu;
  
  	if (mem_cgroup_disabled())
  		return node_page_state(lruvec_pgdat(lruvec), idx);
  
  	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
  	for_each_possible_cpu(cpu)
  		val += per_cpu(pn->lruvec_stat->count[idx], cpu);
  
  	if (val < 0)
  		val = 0;
  
  	return val;

  }

  static inline void __mod_lruvec_state(struct lruvec *lruvec,
  				      enum node_stat_item idx, int val)

  {

  	struct mem_cgroup_per_node *pn;
  
  	__mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
  	if (mem_cgroup_disabled())
  		return;
  	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
  	__mod_memcg_state(pn->memcg, idx, val);
  	__this_cpu_add(pn->lruvec_stat->count[idx], val);
  }
  
  static inline void mod_lruvec_state(struct lruvec *lruvec,
  				    enum node_stat_item idx, int val)
  {
  	struct mem_cgroup_per_node *pn;
  
  	mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
  	if (mem_cgroup_disabled())
  		return;
  	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
  	mod_memcg_state(pn->memcg, idx, val);
  	this_cpu_add(pn->lruvec_stat->count[idx], val);
  }
  
  static inline void __mod_lruvec_page_state(struct page *page,
  					   enum node_stat_item idx, int val)
  {
  	struct mem_cgroup_per_node *pn;
  
  	__mod_node_page_state(page_pgdat(page), idx, val);
  	if (mem_cgroup_disabled() || !page->mem_cgroup)
  		return;
  	__mod_memcg_state(page->mem_cgroup, idx, val);
  	pn = page->mem_cgroup->nodeinfo[page_to_nid(page)];
  	__this_cpu_add(pn->lruvec_stat->count[idx], val);
  }
  
  static inline void mod_lruvec_page_state(struct page *page,
  					 enum node_stat_item idx, int val)
  {
  	struct mem_cgroup_per_node *pn;
  
  	mod_node_page_state(page_pgdat(page), idx, val);
  	if (mem_cgroup_disabled() || !page->mem_cgroup)
  		return;
  	mod_memcg_state(page->mem_cgroup, idx, val);
  	pn = page->mem_cgroup->nodeinfo[page_to_nid(page)];
  	this_cpu_add(pn->lruvec_stat->count[idx], val);

  }

  unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,

  						gfp_t gfp_mask,
  						unsigned long *total_scanned);

  static inline void count_memcg_events(struct mem_cgroup *memcg,
  				      enum vm_event_item idx,
  				      unsigned long count)
  {
  	if (!mem_cgroup_disabled())
  		this_cpu_add(memcg->stat->events[idx], count);
  }

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void count_memcg_page_event(struct page *page,

  					  int idx)

  {
  	if (page->mem_cgroup)
  		count_memcg_events(page->mem_cgroup, idx, 1);
  }
  
  static inline void count_memcg_event_mm(struct mm_struct *mm,
  					enum vm_event_item idx)

  {

  	struct mem_cgroup *memcg;

  	if (mem_cgroup_disabled())
  		return;

  
  	rcu_read_lock();
  	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));

  	if (likely(memcg)) {

  		this_cpu_inc(memcg->stat->events[idx]);

  		if (idx == OOM_KILL)
  			cgroup_file_notify(&memcg->events_file);
  	}

  	rcu_read_unlock();

  }

  #ifdef CONFIG_TRANSPARENT_HUGEPAGE

  void mem_cgroup_split_huge_fixup(struct page *head);

  #endif

  #else /* CONFIG_MEMCG */

  
  #define MEM_CGROUP_ID_SHIFT	0
  #define MEM_CGROUP_ID_MAX	0

  struct mem_cgroup;

  static inline bool mem_cgroup_disabled(void)
  {
  	return true;
  }

  static inline void mem_cgroup_event(struct mem_cgroup *memcg,

  				    enum memcg_event_item event)

  {
  }
  
  static inline bool mem_cgroup_low(struct mem_cgroup *root,
  				  struct mem_cgroup *memcg)
  {
  	return false;
  }

  static inline int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
  					gfp_t gfp_mask,

  					struct mem_cgroup **memcgp,
  					bool compound)

  {

  	*memcgp = NULL;

  	return 0;
  }

  static inline void mem_cgroup_commit_charge(struct page *page,
  					    struct mem_cgroup *memcg,

  					    bool lrucare, bool compound)

  {
  }

  static inline void mem_cgroup_cancel_charge(struct page *page,

  					    struct mem_cgroup *memcg,
  					    bool compound)

  {
  }

  static inline void mem_cgroup_uncharge(struct page *page)

  {
  }

  static inline void mem_cgroup_uncharge_list(struct list_head *page_list)

  {
  }

  static inline void mem_cgroup_migrate(struct page *old, struct page *new)

  {
  }

  static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,

  				struct mem_cgroup *memcg)

  {

  	return node_lruvec(pgdat);

  }

  static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,

  						    struct pglist_data *pgdat)

  {

  	return &pgdat->lruvec;

  }

  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 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 int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
  		int (*fn)(struct task_struct *, void *), void *arg)
  {
  	return 0;
  }

  static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)

  {

  	return 0;
  }
  
  static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
  {
  	WARN_ON_ONCE(id);
  	/* XXX: This should always return root_mem_cgroup */
  	return NULL;

  }

  static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
  {
  	return NULL;
  }

  static inline bool mem_cgroup_online(struct mem_cgroup *memcg)

  {

  	return true;

  }

  static inline unsigned long

  mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)

  {
  	return 0;
  }

  static inline
  unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
  		enum lru_list lru, int zone_idx)
  {
  	return 0;
  }

  static inline unsigned long
  mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
  			     int nid, unsigned int lru_mask)
  {
  	return 0;
  }

  static inline unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
  {
  	return 0;
  }

  static inline void
  mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
  {
  }

  static inline struct mem_cgroup *lock_page_memcg(struct page *page)
  {
  	return NULL;
  }
  
  static inline void __unlock_page_memcg(struct mem_cgroup *memcg)

  {
  }

  static inline void unlock_page_memcg(struct page *page)

  {
  }

  static inline void mem_cgroup_handle_over_high(void)
  {
  }

  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 unsigned long memcg_page_state(struct mem_cgroup *memcg,

  					     int idx)

  {
  	return 0;
  }

  static inline void __mod_memcg_state(struct mem_cgroup *memcg,

  				     int idx,

  				     int nr)

  {
  }

  static inline void mod_memcg_state(struct mem_cgroup *memcg,

  				   int idx,

  				   int nr)

  {
  }

  static inline void __mod_memcg_page_state(struct page *page,

  					  int idx,

  					  int nr)

  {
  }

  static inline void mod_memcg_page_state(struct page *page,

  					int idx,

  					int nr)

  {
  }

  static inline unsigned long lruvec_page_state(struct lruvec *lruvec,
  					      enum node_stat_item idx)

  {

  	return node_page_state(lruvec_pgdat(lruvec), idx);

  }

  static inline void __mod_lruvec_state(struct lruvec *lruvec,
  				      enum node_stat_item idx, int val)

  {

  	__mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
  }
  
  static inline void mod_lruvec_state(struct lruvec *lruvec,
  				    enum node_stat_item idx, int val)
  {
  	mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
  }
  
  static inline void __mod_lruvec_page_state(struct page *page,
  					   enum node_stat_item idx, int val)
  {
  	__mod_node_page_state(page_pgdat(page), idx, val);
  }
  
  static inline void mod_lruvec_page_state(struct page *page,
  					 enum node_stat_item idx, int val)
  {
  	mod_node_page_state(page_pgdat(page), idx, val);

  }

  static inline

  unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, 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 count_memcg_events(struct mem_cgroup *memcg,
  				      enum vm_event_item idx,
  				      unsigned long count)
  {
  }
  
  static inline void count_memcg_page_event(struct page *page,

  					  int idx)

  {
  }

  static inline

  void count_memcg_event_mm(struct mm_struct *mm, enum vm_event_item idx)

  {
  }

  #endif /* CONFIG_MEMCG */

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void __inc_memcg_state(struct mem_cgroup *memcg,

  				     int idx)

  {
  	__mod_memcg_state(memcg, idx, 1);
  }

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void __dec_memcg_state(struct mem_cgroup *memcg,

  				     int idx)

  {
  	__mod_memcg_state(memcg, idx, -1);
  }

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void __inc_memcg_page_state(struct page *page,

  					  int idx)

  {
  	__mod_memcg_page_state(page, idx, 1);
  }

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void __dec_memcg_page_state(struct page *page,

  					  int idx)

  {
  	__mod_memcg_page_state(page, idx, -1);
  }
  
  static inline void __inc_lruvec_state(struct lruvec *lruvec,
  				      enum node_stat_item idx)
  {
  	__mod_lruvec_state(lruvec, idx, 1);
  }
  
  static inline void __dec_lruvec_state(struct lruvec *lruvec,
  				      enum node_stat_item idx)
  {
  	__mod_lruvec_state(lruvec, idx, -1);
  }
  
  static inline void __inc_lruvec_page_state(struct page *page,
  					   enum node_stat_item idx)
  {
  	__mod_lruvec_page_state(page, idx, 1);
  }
  
  static inline void __dec_lruvec_page_state(struct page *page,
  					   enum node_stat_item idx)
  {
  	__mod_lruvec_page_state(page, idx, -1);
  }

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void inc_memcg_state(struct mem_cgroup *memcg,

  				   int idx)

  {
  	mod_memcg_state(memcg, idx, 1);
  }

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void dec_memcg_state(struct mem_cgroup *memcg,

  				   int idx)

  {
  	mod_memcg_state(memcg, idx, -1);
  }

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void inc_memcg_page_state(struct page *page,

  					int idx)

  {
  	mod_memcg_page_state(page, idx, 1);
  }

  /* idx can be of type enum memcg_stat_item or node_stat_item */

  static inline void dec_memcg_page_state(struct page *page,

  					int idx)

  {
  	mod_memcg_page_state(page, idx, -1);
  }
  
  static inline void inc_lruvec_state(struct lruvec *lruvec,
  				    enum node_stat_item idx)
  {
  	mod_lruvec_state(lruvec, idx, 1);
  }
  
  static inline void dec_lruvec_state(struct lruvec *lruvec,
  				    enum node_stat_item idx)
  {
  	mod_lruvec_state(lruvec, idx, -1);
  }
  
  static inline void inc_lruvec_page_state(struct page *page,
  					 enum node_stat_item idx)
  {
  	mod_lruvec_page_state(page, idx, 1);
  }
  
  static inline void dec_lruvec_page_state(struct page *page,
  					 enum node_stat_item idx)
  {
  	mod_lruvec_page_state(page, idx, -1);
  }

  #ifdef CONFIG_CGROUP_WRITEBACK

  struct list_head *mem_cgroup_cgwb_list(struct mem_cgroup *memcg);

  struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb);

  void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
  			 unsigned long *pheadroom, unsigned long *pdirty,
  			 unsigned long *pwriteback);

  
  #else	/* CONFIG_CGROUP_WRITEBACK */
  
  static inline struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
  {
  	return NULL;
  }

  static inline void mem_cgroup_wb_stats(struct bdi_writeback *wb,

  				       unsigned long *pfilepages,
  				       unsigned long *pheadroom,

  				       unsigned long *pdirty,
  				       unsigned long *pwriteback)
  {
  }

  #endif	/* CONFIG_CGROUP_WRITEBACK */

  struct sock;

  bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);
  void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);

  #ifdef CONFIG_MEMCG

  extern struct static_key_false memcg_sockets_enabled_key;
  #define mem_cgroup_sockets_enabled static_branch_unlikely(&memcg_sockets_enabled_key)

  void mem_cgroup_sk_alloc(struct sock *sk);
  void mem_cgroup_sk_free(struct sock *sk);

  static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)

  {

  	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_pressure)

  		return true;

  	do {
  		if (time_before(jiffies, memcg->socket_pressure))
  			return true;
  	} while ((memcg = parent_mem_cgroup(memcg)));
  	return false;

  }
  #else

  #define mem_cgroup_sockets_enabled 0

  static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
  static inline void mem_cgroup_sk_free(struct sock *sk) { };

  static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)

  {
  	return false;
  }
  #endif

  struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep);
  void memcg_kmem_put_cache(struct kmem_cache *cachep);
  int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
  			    struct mem_cgroup *memcg);
  int memcg_kmem_charge(struct page *page, gfp_t gfp, int order);
  void memcg_kmem_uncharge(struct page *page, int order);

  #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)

  extern struct static_key_false memcg_kmem_enabled_key;

  extern struct workqueue_struct *memcg_kmem_cache_wq;

  extern int memcg_nr_cache_ids;

  void memcg_get_cache_ids(void);
  void memcg_put_cache_ids(void);

  
  /*
   * 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_nr_cache_ids; (_idx)++)

  static inline bool memcg_kmem_enabled(void)
  {

  	return static_branch_unlikely(&memcg_kmem_enabled_key);

  }
  
  /*

   * helper for accessing a memcg's index. It will be used as an index in the

   * child cache array in kmem_cache, and also to derive its name. This function
   * will return -1 when this is not a kmem-limited memcg.
   */
  static inline int memcg_cache_id(struct mem_cgroup *memcg)
  {
  	return memcg ? memcg->kmemcg_id : -1;
  }

  #else

  #define for_each_memcg_cache_index(_idx)	\
  	for (; NULL; )

  static inline bool memcg_kmem_enabled(void)
  {
  	return false;
  }

  static inline int memcg_cache_id(struct mem_cgroup *memcg)
  {
  	return -1;
  }

  static inline void memcg_get_cache_ids(void)
  {
  }
  
  static inline void memcg_put_cache_ids(void)
  {
  }

  #endif /* CONFIG_MEMCG && !CONFIG_SLOB */

  #endif /* _LINUX_MEMCONTROL_H */