#include <linux/mm.h>
  #include <linux/mmzone.h>
  #include <linux/bootmem.h>
  #include <linux/bit_spinlock.h>
  #include <linux/page_cgroup.h>
  #include <linux/hash.h>

  #include <linux/slab.h>

  #include <linux/memory.h>

  #include <linux/vmalloc.h>

  #include <linux/cgroup.h>

  #include <linux/swapops.h>

  
  static void __meminit
  __init_page_cgroup(struct page_cgroup *pc, unsigned long pfn)
  {
  	pc->flags = 0;
  	pc->mem_cgroup = NULL;
  	pc->page = pfn_to_page(pfn);

  	INIT_LIST_HEAD(&pc->lru);

  }
  static unsigned long total_usage;
  
  #if !defined(CONFIG_SPARSEMEM)

  void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)

  {
  	pgdat->node_page_cgroup = NULL;
  }
  
  struct page_cgroup *lookup_page_cgroup(struct page *page)
  {
  	unsigned long pfn = page_to_pfn(page);
  	unsigned long offset;
  	struct page_cgroup *base;
  
  	base = NODE_DATA(page_to_nid(page))->node_page_cgroup;
  	if (unlikely(!base))
  		return NULL;
  
  	offset = pfn - NODE_DATA(page_to_nid(page))->node_start_pfn;
  	return base + offset;
  }
  
  static int __init alloc_node_page_cgroup(int nid)
  {
  	struct page_cgroup *base, *pc;
  	unsigned long table_size;
  	unsigned long start_pfn, nr_pages, index;
  
  	start_pfn = NODE_DATA(nid)->node_start_pfn;
  	nr_pages = NODE_DATA(nid)->node_spanned_pages;

  	if (!nr_pages)
  		return 0;

  	table_size = sizeof(struct page_cgroup) * nr_pages;

  
  	base = __alloc_bootmem_node_nopanic(NODE_DATA(nid),
  			table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
  	if (!base)

  		return -ENOMEM;
  	for (index = 0; index < nr_pages; index++) {
  		pc = base + index;
  		__init_page_cgroup(pc, start_pfn + index);
  	}
  	NODE_DATA(nid)->node_page_cgroup = base;
  	total_usage += table_size;
  	return 0;
  }

  void __init page_cgroup_init_flatmem(void)

  {
  
  	int nid, fail;

  	if (mem_cgroup_disabled())

  		return;

  	for_each_online_node(nid)  {
  		fail = alloc_node_page_cgroup(nid);
  		if (fail)
  			goto fail;
  	}
  	printk(KERN_INFO "allocated %ld bytes of page_cgroup
  ", total_usage);

  	printk(KERN_INFO "please try 'cgroup_disable=memory' option if you"
  	" don't want memory cgroups
  ");

  	return;
  fail:

  	printk(KERN_CRIT "allocation of page_cgroup failed.
  ");
  	printk(KERN_CRIT "please try 'cgroup_disable=memory' boot option
  ");

  	panic("Out of memory");
  }
  
  #else /* CONFIG_FLAT_NODE_MEM_MAP */
  
  struct page_cgroup *lookup_page_cgroup(struct page *page)
  {
  	unsigned long pfn = page_to_pfn(page);
  	struct mem_section *section = __pfn_to_section(pfn);

  	if (!section->page_cgroup)
  		return NULL;

  	return section->page_cgroup + pfn;
  }

  /* __alloc_bootmem...() is protected by !slab_available() */

  static int __init_refok init_section_page_cgroup(unsigned long pfn)

  {

  	struct mem_section *section = __pfn_to_section(pfn);

  	struct page_cgroup *base, *pc;
  	unsigned long table_size;
  	int nid, index;

  	if (!section->page_cgroup) {
  		nid = page_to_nid(pfn_to_page(pfn));
  		table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;

  		VM_BUG_ON(!slab_is_available());

  		if (node_state(nid, N_HIGH_MEMORY)) {
  			base = kmalloc_node(table_size,

  				GFP_KERNEL | __GFP_NOWARN, nid);

  			if (!base)
  				base = vmalloc_node(table_size, nid);
  		} else {
  			base = kmalloc(table_size, GFP_KERNEL | __GFP_NOWARN);
  			if (!base)
  				base = vmalloc(table_size);
  		}

  	} else {
  		/*
   		 * We don't have to allocate page_cgroup again, but
  		 * address of memmap may be changed. So, we have to initialize
  		 * again.
  		 */
  		base = section->page_cgroup + pfn;
  		table_size = 0;
  		/* check address of memmap is changed or not. */
  		if (base->page == pfn_to_page(pfn))
  			return 0;

  	}

  
  	if (!base) {
  		printk(KERN_ERR "page cgroup allocation failure
  ");
  		return -ENOMEM;
  	}
  
  	for (index = 0; index < PAGES_PER_SECTION; index++) {
  		pc = base + index;
  		__init_page_cgroup(pc, pfn + index);
  	}

  	section->page_cgroup = base - pfn;
  	total_usage += table_size;
  	return 0;
  }
  #ifdef CONFIG_MEMORY_HOTPLUG
  void __free_page_cgroup(unsigned long pfn)
  {
  	struct mem_section *ms;
  	struct page_cgroup *base;
  
  	ms = __pfn_to_section(pfn);
  	if (!ms || !ms->page_cgroup)
  		return;
  	base = ms->page_cgroup + pfn;

  	if (is_vmalloc_addr(base)) {

  		vfree(base);

  		ms->page_cgroup = NULL;
  	} else {
  		struct page *page = virt_to_page(base);
  		if (!PageReserved(page)) { /* Is bootmem ? */
  			kfree(base);
  			ms->page_cgroup = NULL;
  		}
  	}

  }

  int __meminit online_page_cgroup(unsigned long start_pfn,

  			unsigned long nr_pages,
  			int nid)
  {
  	unsigned long start, end, pfn;
  	int fail = 0;

  	start = start_pfn & ~(PAGES_PER_SECTION - 1);

  	end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);
  
  	for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
  		if (!pfn_present(pfn))
  			continue;
  		fail = init_section_page_cgroup(pfn);
  	}
  	if (!fail)
  		return 0;
  
  	/* rollback */
  	for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
  		__free_page_cgroup(pfn);
  
  	return -ENOMEM;
  }

  int __meminit offline_page_cgroup(unsigned long start_pfn,

  		unsigned long nr_pages, int nid)
  {
  	unsigned long start, end, pfn;

  	start = start_pfn & ~(PAGES_PER_SECTION - 1);

  	end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);
  
  	for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
  		__free_page_cgroup(pfn);
  	return 0;
  
  }

  static int __meminit page_cgroup_callback(struct notifier_block *self,

  			       unsigned long action, void *arg)
  {
  	struct memory_notify *mn = arg;
  	int ret = 0;
  	switch (action) {
  	case MEM_GOING_ONLINE:
  		ret = online_page_cgroup(mn->start_pfn,
  				   mn->nr_pages, mn->status_change_nid);
  		break;

  	case MEM_OFFLINE:
  		offline_page_cgroup(mn->start_pfn,
  				mn->nr_pages, mn->status_change_nid);
  		break;

  	case MEM_CANCEL_ONLINE:

  	case MEM_GOING_OFFLINE:
  		break;
  	case MEM_ONLINE:
  	case MEM_CANCEL_OFFLINE:
  		break;
  	}

  
  	if (ret)
  		ret = notifier_from_errno(ret);
  	else
  		ret = NOTIFY_OK;

  	return ret;
  }
  
  #endif
  
  void __init page_cgroup_init(void)
  {
  	unsigned long pfn;
  	int fail = 0;

  	if (mem_cgroup_disabled())

  		return;

  	for (pfn = 0; !fail && pfn < max_pfn; pfn += PAGES_PER_SECTION) {
  		if (!pfn_present(pfn))
  			continue;
  		fail = init_section_page_cgroup(pfn);
  	}
  	if (fail) {

  		printk(KERN_CRIT "try 'cgroup_disable=memory' boot option
  ");

  		panic("Out of memory");
  	} else {
  		hotplug_memory_notifier(page_cgroup_callback, 0);
  	}
  	printk(KERN_INFO "allocated %ld bytes of page_cgroup
  ", total_usage);

  	printk(KERN_INFO "please try 'cgroup_disable=memory' option if you don't"
  	" want memory cgroups
  ");

  }

  void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)

  {
  	return;
  }
  
  #endif

  
  
  #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
  
  static DEFINE_MUTEX(swap_cgroup_mutex);
  struct swap_cgroup_ctrl {
  	struct page **map;
  	unsigned long length;

  	spinlock_t	lock;

  };
  
  struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];

  struct swap_cgroup {

  	unsigned short		id;

  };
  #define SC_PER_PAGE	(PAGE_SIZE/sizeof(struct swap_cgroup))
  #define SC_POS_MASK	(SC_PER_PAGE - 1)
  
  /*
   * SwapCgroup implements "lookup" and "exchange" operations.
   * In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
   * against SwapCache. At swap_free(), this is accessed directly from swap.
   *
   * This means,
   *  - we have no race in "exchange" when we're accessed via SwapCache because
   *    SwapCache(and its swp_entry) is under lock.
   *  - When called via swap_free(), there is no user of this entry and no race.
   * Then, we don't need lock around "exchange".
   *
   * TODO: we can push these buffers out to HIGHMEM.
   */
  
  /*
   * allocate buffer for swap_cgroup.
   */
  static int swap_cgroup_prepare(int type)
  {
  	struct page *page;
  	struct swap_cgroup_ctrl *ctrl;
  	unsigned long idx, max;

  	ctrl = &swap_cgroup_ctrl[type];
  
  	for (idx = 0; idx < ctrl->length; idx++) {
  		page = alloc_page(GFP_KERNEL | __GFP_ZERO);
  		if (!page)
  			goto not_enough_page;
  		ctrl->map[idx] = page;
  	}
  	return 0;
  not_enough_page:
  	max = idx;
  	for (idx = 0; idx < max; idx++)
  		__free_page(ctrl->map[idx]);
  
  	return -ENOMEM;
  }
  
  /**

   * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
   * @end: swap entry to be cmpxchged
   * @old: old id
   * @new: new id
   *
   * Returns old id at success, 0 at failure.
   * (There is no mem_cgroup useing 0 as its id)
   */
  unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
  					unsigned short old, unsigned short new)
  {
  	int type = swp_type(ent);
  	unsigned long offset = swp_offset(ent);
  	unsigned long idx = offset / SC_PER_PAGE;
  	unsigned long pos = offset & SC_POS_MASK;
  	struct swap_cgroup_ctrl *ctrl;
  	struct page *mappage;
  	struct swap_cgroup *sc;

  	unsigned long flags;
  	unsigned short retval;

  
  	ctrl = &swap_cgroup_ctrl[type];
  
  	mappage = ctrl->map[idx];
  	sc = page_address(mappage);
  	sc += pos;

  	spin_lock_irqsave(&ctrl->lock, flags);
  	retval = sc->id;
  	if (retval == old)
  		sc->id = new;

  	else

  		retval = 0;
  	spin_unlock_irqrestore(&ctrl->lock, flags);
  	return retval;

  }
  
  /**

   * swap_cgroup_record - record mem_cgroup for this swp_entry.
   * @ent: swap entry to be recorded into
   * @mem: mem_cgroup to be recorded
   *

   * Returns old value at success, 0 at failure.
   * (Of course, old value can be 0.)

   */

  unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)

  {
  	int type = swp_type(ent);
  	unsigned long offset = swp_offset(ent);
  	unsigned long idx = offset / SC_PER_PAGE;
  	unsigned long pos = offset & SC_POS_MASK;
  	struct swap_cgroup_ctrl *ctrl;
  	struct page *mappage;
  	struct swap_cgroup *sc;

  	unsigned short old;

  	unsigned long flags;

  	ctrl = &swap_cgroup_ctrl[type];
  
  	mappage = ctrl->map[idx];
  	sc = page_address(mappage);
  	sc += pos;

  	spin_lock_irqsave(&ctrl->lock, flags);
  	old = sc->id;
  	sc->id = id;
  	spin_unlock_irqrestore(&ctrl->lock, flags);

  
  	return old;
  }
  
  /**
   * lookup_swap_cgroup - lookup mem_cgroup tied to swap entry
   * @ent: swap entry to be looked up.
   *

   * Returns CSS ID of mem_cgroup at success. 0 at failure. (0 is invalid ID)

   */

  unsigned short lookup_swap_cgroup(swp_entry_t ent)

  {
  	int type = swp_type(ent);
  	unsigned long offset = swp_offset(ent);
  	unsigned long idx = offset / SC_PER_PAGE;
  	unsigned long pos = offset & SC_POS_MASK;
  	struct swap_cgroup_ctrl *ctrl;
  	struct page *mappage;
  	struct swap_cgroup *sc;

  	unsigned short ret;

  	ctrl = &swap_cgroup_ctrl[type];
  	mappage = ctrl->map[idx];
  	sc = page_address(mappage);
  	sc += pos;

  	ret = sc->id;

  	return ret;
  }
  
  int swap_cgroup_swapon(int type, unsigned long max_pages)
  {
  	void *array;
  	unsigned long array_size;
  	unsigned long length;
  	struct swap_cgroup_ctrl *ctrl;
  
  	if (!do_swap_account)
  		return 0;
  
  	length = ((max_pages/SC_PER_PAGE) + 1);
  	array_size = length * sizeof(void *);
  
  	array = vmalloc(array_size);
  	if (!array)
  		goto nomem;
  
  	memset(array, 0, array_size);
  	ctrl = &swap_cgroup_ctrl[type];
  	mutex_lock(&swap_cgroup_mutex);
  	ctrl->length = length;
  	ctrl->map = array;

  	spin_lock_init(&ctrl->lock);

  	if (swap_cgroup_prepare(type)) {
  		/* memory shortage */
  		ctrl->map = NULL;
  		ctrl->length = 0;
  		vfree(array);
  		mutex_unlock(&swap_cgroup_mutex);
  		goto nomem;
  	}
  	mutex_unlock(&swap_cgroup_mutex);

  	return 0;
  nomem:
  	printk(KERN_INFO "couldn't allocate enough memory for swap_cgroup.
  ");
  	printk(KERN_INFO
  		"swap_cgroup can be disabled by noswapaccount boot option
  ");
  	return -ENOMEM;
  }
  
  void swap_cgroup_swapoff(int type)
  {
  	int i;
  	struct swap_cgroup_ctrl *ctrl;
  
  	if (!do_swap_account)
  		return;
  
  	mutex_lock(&swap_cgroup_mutex);
  	ctrl = &swap_cgroup_ctrl[type];
  	if (ctrl->map) {
  		for (i = 0; i < ctrl->length; i++) {
  			struct page *page = ctrl->map[i];
  			if (page)
  				__free_page(page);
  		}
  		vfree(ctrl->map);
  		ctrl->map = NULL;
  		ctrl->length = 0;
  	}
  	mutex_unlock(&swap_cgroup_mutex);
  }
  
  #endif