text: #ifndef _LINUX_MM_H
  #define _LINUX_MM_H
  
  #include <linux/errno.h>
  
  #ifdef __KERNEL__
  
  #include <linux/gfp.h>
  #include <linux/bug.h>
  #include <linux/list.h>
  #include <linux/mmzone.h>
  #include <linux/rbtree.h>
  #include <linux/atomic.h>
  #include <linux/debug_locks.h>
  #include <linux/mm_types.h>
  #include <linux/range.h>
  #include <linux/pfn.h>
  #include <linux/bit_spinlock.h>
  #include <linux/shrinker.h>
  
  #ifdef CONFIG_STRICT_MEMORY_RWX
  extern char __init_data_begin[];
  #endif
  
  struct mempolicy;
  struct anon_vma;
  struct anon_vma_chain;
  struct file_ra_state;
  struct user_struct;
  struct writeback_control;
  
  #ifndef CONFIG_DISCONTIGMEM          /* Don't use mapnrs, do it properly */
  extern unsigned long max_mapnr;
  #endif
  
  extern unsigned long num_physpages;
  extern unsigned long totalram_pages;
  #ifdef CONFIG_FIX_MOVABLE_ZONE
  extern unsigned long total_unmovable_pages;
  #endif
  extern void * high_memory;
  extern int page_cluster;
  
  #ifdef CONFIG_SYSCTL
  extern int sysctl_legacy_va_layout;
  #else
  #define sysctl_legacy_va_layout 0
  #endif
  
  #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
  extern const int mmap_rnd_bits_min;
  extern const int mmap_rnd_bits_max;
  extern int mmap_rnd_bits __read_mostly;
  #endif
  #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
  extern const int mmap_rnd_compat_bits_min;
  extern const int mmap_rnd_compat_bits_max;
  extern int mmap_rnd_compat_bits __read_mostly;
  #endif
  
  #include <asm/page.h>
  #include <asm/pgtable.h>
  #include <asm/processor.h>
  
  extern unsigned long sysctl_user_reserve_kbytes;
  extern unsigned long sysctl_admin_reserve_kbytes;
  
  #define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
  
  /* to align the pointer to the (next) page boundary */
  #define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
  
  /*
   * Linux kernel virtual memory manager primitives.
   * The idea being to have a "virtual" mm in the same way
   * we have a virtual fs - giving a cleaner interface to the
   * mm details, and allowing different kinds of memory mappings
   * (from shared memory to executable loading to arbitrary
   * mmap() functions).
   */
  
  extern struct kmem_cache *vm_area_cachep;
  
  #ifndef CONFIG_MMU
  extern struct rb_root nommu_region_tree;
  extern struct rw_semaphore nommu_region_sem;
  
  extern unsigned int kobjsize(const void *objp);
  #endif
  
  #ifdef CONFIG_ZSWAP
  extern int sysctl_zswap_compact;
  extern int sysctl_zswap_compaction_handler(struct ctl_table *table, int write,
  			void __user *buffer, size_t *length, loff_t *ppos);
  #endif
  
  /*
   * vm_flags in vm_area_struct, see mm_types.h.
   */
  #define VM_NONE		0x00000000
  
  #define VM_READ		0x00000001	/* currently active flags */
  #define VM_WRITE	0x00000002
  #define VM_EXEC		0x00000004
  #define VM_SHARED	0x00000008
  
  /* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
  #define VM_MAYREAD	0x00000010	/* limits for mprotect() etc */
  #define VM_MAYWRITE	0x00000020
  #define VM_MAYEXEC	0x00000040
  #define VM_MAYSHARE	0x00000080
  
  #define VM_GROWSDOWN	0x00000100	/* general info on the segment */
  #define VM_PFNMAP	0x00000400	/* Page-ranges managed without "struct page", just pure PFN */
  #define VM_DENYWRITE	0x00000800	/* ETXTBSY on write attempts.. */
  
  #define VM_LOCKED	0x00002000
  #define VM_IO           0x00004000	/* Memory mapped I/O or similar */
  
  					/* Used by sys_madvise() */
  #define VM_SEQ_READ	0x00008000	/* App will access data sequentially */
  #define VM_RAND_READ	0x00010000	/* App will not benefit from clustered reads */
  
  #define VM_DONTCOPY	0x00020000      /* Do not copy this vma on fork */
  #define VM_DONTEXPAND	0x00040000	/* Cannot expand with mremap() */
  #define VM_ACCOUNT	0x00100000	/* Is a VM accounted object */
  #define VM_NORESERVE	0x00200000	/* should the VM suppress accounting */
  #define VM_HUGETLB	0x00400000	/* Huge TLB Page VM */
  #define VM_NONLINEAR	0x00800000	/* Is non-linear (remap_file_pages) */
  #define VM_ARCH_1	0x01000000	/* Architecture-specific flag */
  #define VM_DONTDUMP	0x04000000	/* Do not include in the core dump */
  
  #define VM_MIXEDMAP	0x10000000	/* Can contain "struct page" and pure PFN pages */
  #define VM_HUGEPAGE	0x20000000	/* MADV_HUGEPAGE marked this vma */
  #define VM_NOHUGEPAGE	0x40000000	/* MADV_NOHUGEPAGE marked this vma */
  #define VM_MERGEABLE	0x80000000	/* KSM may merge identical pages */
  
  #if defined(CONFIG_X86)
  # define VM_PAT		VM_ARCH_1	/* PAT reserves whole VMA at once (x86) */
  #elif defined(CONFIG_PPC)
  # define VM_SAO		VM_ARCH_1	/* Strong Access Ordering (powerpc) */
  #elif defined(CONFIG_PARISC)
  # define VM_GROWSUP	VM_ARCH_1
  #elif defined(CONFIG_METAG)
  # define VM_GROWSUP	VM_ARCH_1
  #elif defined(CONFIG_IA64)
  # define VM_GROWSUP	VM_ARCH_1
  #elif !defined(CONFIG_MMU)
  # define VM_MAPPED_COPY	VM_ARCH_1	/* T if mapped copy of data (nommu mmap) */
  #endif
  
  #ifndef VM_GROWSUP
  # define VM_GROWSUP	VM_NONE
  #endif
  
  /* Bits set in the VMA until the stack is in its final location */
  #define VM_STACK_INCOMPLETE_SETUP	(VM_RAND_READ | VM_SEQ_READ)
  
  #ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */
  #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
  #endif
  
  #ifdef CONFIG_STACK_GROWSUP
  #define VM_STACK_FLAGS	(VM_GROWSUP | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
  #else
  #define VM_STACK_FLAGS	(VM_GROWSDOWN | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
  #endif
  
  #define VM_READHINTMASK			(VM_SEQ_READ | VM_RAND_READ)
  #define VM_ClearReadHint(v)		(v)->vm_flags &= ~VM_READHINTMASK
  #define VM_NormalReadHint(v)		(!((v)->vm_flags & VM_READHINTMASK))
  #define VM_SequentialReadHint(v)	((v)->vm_flags & VM_SEQ_READ)
  #define VM_RandomReadHint(v)		((v)->vm_flags & VM_RAND_READ)
  
  /*
   * Special vmas that are non-mergable, non-mlock()able.
   * Note: mm/huge_memory.c VM_NO_THP depends on this definition.
   */
  #define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP)
  
  /*
   * mapping from the currently active vm_flags protection bits (the
   * low four bits) to a page protection mask..
   */
  extern pgprot_t protection_map[16];
  
  #define FAULT_FLAG_WRITE	0x01	/* Fault was a write access */
  #define FAULT_FLAG_NONLINEAR	0x02	/* Fault was via a nonlinear mapping */
  #define FAULT_FLAG_MKWRITE	0x04	/* Fault was mkwrite of existing pte */
  #define FAULT_FLAG_ALLOW_RETRY	0x08	/* Retry fault if blocking */
  #define FAULT_FLAG_RETRY_NOWAIT	0x10	/* Don't drop mmap_sem and wait when retrying */
  #define FAULT_FLAG_KILLABLE	0x20	/* The fault task is in SIGKILL killable region */
  #define FAULT_FLAG_TRIED	0x40	/* second try */
  #define FAULT_FLAG_USER		0x80	/* The fault originated in userspace */
  
  /*
   * vm_fault is filled by the the pagefault handler and passed to the vma's
   * ->fault function. The vma's ->fault is responsible for returning a bitmask
   * of VM_FAULT_xxx flags that give details about how the fault was handled.
   *
   * pgoff should be used in favour of virtual_address, if possible. If pgoff
   * is used, one may implement ->remap_pages to get nonlinear mapping support.
   */
  struct vm_fault {
  	unsigned int flags;		/* FAULT_FLAG_xxx flags */
  	pgoff_t pgoff;			/* Logical page offset based on vma */
  	void __user *virtual_address;	/* Faulting virtual address */
  
  	struct page *page;		/* ->fault handlers should return a
  					 * page here, unless VM_FAULT_NOPAGE
  					 * is set (which is also implied by
  					 * VM_FAULT_ERROR).
  					 */
  };
  
  /*
   * These are the virtual MM functions - opening of an area, closing and
   * unmapping it (needed to keep files on disk up-to-date etc), pointer
   * to the functions called when a no-page or a wp-page exception occurs. 
   */
  struct vm_operations_struct {
  	void (*open)(struct vm_area_struct * area);
  	void (*close)(struct vm_area_struct * area);
  	int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
  
  	/* notification that a previously read-only page is about to become
  	 * writable, if an error is returned it will cause a SIGBUS */
  	int (*page_mkwrite)(struct vm_area_struct *vma, struct vm_fault *vmf);
  
  	/* called by access_process_vm when get_user_pages() fails, typically
  	 * for use by special VMAs that can switch between memory and hardware
  	 */
  	int (*access)(struct vm_area_struct *vma, unsigned long addr,
  		      void *buf, int len, int write);
  #ifdef CONFIG_NUMA
  	/*
  	 * set_policy() op must add a reference to any non-NULL @new mempolicy
  	 * to hold the policy upon return.  Caller should pass NULL @new to
  	 * remove a policy and fall back to surrounding context--i.e. do not
  	 * install a MPOL_DEFAULT policy, nor the task or system default
  	 * mempolicy.
  	 */
  	int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
  
  	/*
  	 * get_policy() op must add reference [mpol_get()] to any policy at
  	 * (vma,addr) marked as MPOL_SHARED.  The shared policy infrastructure
  	 * in mm/mempolicy.c will do this automatically.
  	 * get_policy() must NOT add a ref if the policy at (vma,addr) is not
  	 * marked as MPOL_SHARED. vma policies are protected by the mmap_sem.
  	 * If no [shared/vma] mempolicy exists at the addr, get_policy() op
  	 * must return NULL--i.e., do not "fallback" to task or system default
  	 * policy.
  	 */
  	struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
  					unsigned long addr);
  	int (*migrate)(struct vm_area_struct *vma, const nodemask_t *from,
  		const nodemask_t *to, unsigned long flags);
  #endif
  	/* called by sys_remap_file_pages() to populate non-linear mapping */
  	int (*remap_pages)(struct vm_area_struct *vma, unsigned long addr,
  			   unsigned long size, pgoff_t pgoff);
  };
  
  struct mmu_gather;
  struct inode;
  
  #define page_private(page)		((page)->private)
  #define set_page_private(page, v)	((page)->private = (v))
  
  /* It's valid only if the page is free path or free_list */
  static inline void set_freepage_migratetype(struct page *page, int migratetype)
  {
  	page->index = migratetype;
  }
  
  /* It's valid only if the page is free path or free_list */
  static inline int get_freepage_migratetype(struct page *page)
  {
  	return page->index;
  }
  
  /*
   * FIXME: take this include out, include page-flags.h in
   * files which need it (119 of them)
   */
  #include <linux/page-flags.h>
  #include <linux/huge_mm.h>
  
  /*
   * Methods to modify the page usage count.
   *
   * What counts for a page usage:
   * - cache mapping   (page->mapping)
   * - private data    (page->private)
   * - page mapped in a task's page tables, each mapping
   *   is counted separately
   *
   * Also, many kernel routines increase the page count before a critical
   * routine so they can be sure the page doesn't go away from under them.
   */
  
  /*
   * Drop a ref, return true if the refcount fell to zero (the page has no users)
   */
  static inline int put_page_testzero(struct page *page)
  {
  	VM_BUG_ON(atomic_read(&page->_count) == 0);
  	return atomic_dec_and_test(&page->_count);
  }
  
  /*
   * Try to grab a ref unless the page has a refcount of zero, return false if
   * that is the case.
   */
  static inline int get_page_unless_zero(struct page *page)
  {
  	return atomic_inc_not_zero(&page->_count);
  }
  
  extern int page_is_ram(unsigned long pfn);
  
  /* Support for virtually mapped pages */
  struct page *vmalloc_to_page(const void *addr);
  unsigned long vmalloc_to_pfn(const void *addr);
  
  /*
   * Determine if an address is within the vmalloc range
   *
   * On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there
   * is no special casing required.
   */
  
  #ifdef CONFIG_MMU
  extern int is_vmalloc_addr(const void *x);
  #else
  static inline int is_vmalloc_addr(const void *x)
  {
  	return 0;
  }
  #endif
  
  #ifdef CONFIG_MMU
  extern int is_vmalloc_or_module_addr(const void *x);
  #else
  static inline int is_vmalloc_or_module_addr(const void *x)
  {
  	return 0;
  }
  #endif
  
  extern void kvfree(const void *addr);
  
  static inline void compound_lock(struct page *page)
  {
  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  	VM_BUG_ON(PageSlab(page));
  	bit_spin_lock(PG_compound_lock, &page->flags);
  #endif
  }
  
  static inline void compound_unlock(struct page *page)
  {
  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  	VM_BUG_ON(PageSlab(page));
  	bit_spin_unlock(PG_compound_lock, &page->flags);
  #endif
  }
  
  static inline unsigned long compound_lock_irqsave(struct page *page)
  {
  	unsigned long uninitialized_var(flags);
  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  	local_irq_save(flags);
  	compound_lock(page);
  #endif
  	return flags;
  }
  
  static inline void compound_unlock_irqrestore(struct page *page,
  					      unsigned long flags)
  {
  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  	compound_unlock(page);
  	local_irq_restore(flags);
  #endif
  }
  
  static inline struct page *compound_head(struct page *page)
  {
  	if (unlikely(PageTail(page))) {
  		struct page *head = page->first_page;
  
  		/*
  		 * page->first_page may be a dangling pointer to an old
  		 * compound page, so recheck that it is still a tail
  		 * page before returning.
  		 */
  		smp_rmb();
  		if (likely(PageTail(page)))
  			return head;
  	}
  	return page;
  }
  
  /*
   * The atomic page->_mapcount, starts from -1: so that transitions
   * both from it and to it can be tracked, using atomic_inc_and_test
   * and atomic_add_negative(-1).
   */
  static inline void page_mapcount_reset(struct page *page)
  {
  	atomic_set(&(page)->_mapcount, -1);
  }
  
  static inline int page_mapcount(struct page *page)
  {
  	return atomic_read(&(page)->_mapcount) + 1;
  }
  
  static inline int page_count(struct page *page)
  {
  	return atomic_read(&compound_head(page)->_count);
  }
  
  static inline void get_huge_page_tail(struct page *page)
  {
  	/*
  	 * __split_huge_page_refcount() cannot run
  	 * from under us.
  	 */
  	VM_BUG_ON(page_mapcount(page) < 0);
  	VM_BUG_ON(atomic_read(&page->_count) != 0);
  	atomic_inc(&page->_mapcount);
  }
  
  extern bool __get_page_tail(struct page *page);
  
  static inline void get_page(struct page *page)
  {
  	if (unlikely(PageTail(page)))
  		if (likely(__get_page_tail(page)))
  			return;
  	/*
  	 * Getting a normal page or the head of a compound page
  	 * requires to already have an elevated page->_count.
  	 */
  	VM_BUG_ON(atomic_read(&page->_count) <= 0);
  	atomic_inc(&page->_count);
  }
  
  static inline struct page *virt_to_head_page(const void *x)
  {
  	struct page *page = virt_to_page(x);
  	return compound_head(page);
  }
  
  /*
   * Setup the page count before being freed into the page allocator for
   * the first time (boot or memory hotplug)
   */
  static inline void init_page_count(struct page *page)
  {
  	atomic_set(&page->_count, 1);
  }
  
  /*
   * PageBuddy() indicate that the page is free and in the buddy system
   * (see mm/page_alloc.c).
   *
   * PAGE_BUDDY_MAPCOUNT_VALUE must be <= -2 but better not too close to
   * -2 so that an underflow of the page_mapcount() won't be mistaken
   * for a genuine PAGE_BUDDY_MAPCOUNT_VALUE. -128 can be created very
   * efficiently by most CPU architectures.
   */
  #define PAGE_BUDDY_MAPCOUNT_VALUE (-128)
  
  static inline int PageBuddy(struct page *page)
  {
  	return atomic_read(&page->_mapcount) == PAGE_BUDDY_MAPCOUNT_VALUE;
  }
  
  static inline void __SetPageBuddy(struct page *page)
  {
  	VM_BUG_ON(atomic_read(&page->_mapcount) != -1);
  	atomic_set(&page->_mapcount, PAGE_BUDDY_MAPCOUNT_VALUE);
  }
  
  static inline void __ClearPageBuddy(struct page *page)
  {
  	VM_BUG_ON(!PageBuddy(page));
  	atomic_set(&page->_mapcount, -1);
  }
  
  void put_page(struct page *page);
  void put_pages_list(struct list_head *pages);
  
  void split_page(struct page *page, unsigned int order);
  int split_free_page(struct page *page);
  
  /*
   * Compound pages have a destructor function.  Provide a
   * prototype for that function and accessor functions.
   * These are _only_ valid on the head of a PG_compound page.
   */
  typedef void compound_page_dtor(struct page *);
  
  static inline void set_compound_page_dtor(struct page *page,
  						compound_page_dtor *dtor)
  {
  	page[1].lru.next = (void *)dtor;
  }
  
  static inline compound_page_dtor *get_compound_page_dtor(struct page *page)
  {
  	return (compound_page_dtor *)page[1].lru.next;
  }
  
  static inline int compound_order(struct page *page)
  {
  	if (!PageHead(page))
  		return 0;
  	return (unsigned long)page[1].lru.prev;
  }
  
  static inline int compound_trans_order(struct page *page)
  {
  	int order;
  	unsigned long flags;
  
  	if (!PageHead(page))
  		return 0;
  
  	flags = compound_lock_irqsave(page);
  	order = compound_order(page);
  	compound_unlock_irqrestore(page, flags);
  	return order;
  }
  
  static inline void set_compound_order(struct page *page, unsigned long order)
  {
  	page[1].lru.prev = (void *)order;
  }
  
  #ifdef CONFIG_MMU
  /*
   * Do pte_mkwrite, but only if the vma says VM_WRITE.  We do this when
   * servicing faults for write access.  In the normal case, do always want
   * pte_mkwrite.  But get_user_pages can cause write faults for mappings
   * that do not have writing enabled, when used by access_process_vm.
   */
  static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
  {
  	if (likely(vma->vm_flags & VM_WRITE))
  		pte = pte_mkwrite(pte);
  	return pte;
  }
  #endif
  
  /*
   * Multiple processes may "see" the same page. E.g. for untouched
   * mappings of /dev/null, all processes see the same page full of
   * zeroes, and text pages of executables and shared libraries have
   * only one copy in memory, at most, normally.
   *
   * For the non-reserved pages, page_count(page) denotes a reference count.
   *   page_count() == 0 means the page is free. page->lru is then used for
   *   freelist management in the buddy allocator.
   *   page_count() > 0  means the page has been allocated.
   *
   * Pages are allocated by the slab allocator in order to provide memory
   * to kmalloc and kmem_cache_alloc. In this case, the management of the
   * page, and the fields in 'struct page' are the responsibility of mm/slab.c
   * unless a particular usage is carefully commented. (the responsibility of
   * freeing the kmalloc memory is the caller's, of course).
   *
   * A page may be used by anyone else who does a __get_free_page().
   * In this case, page_count still tracks the references, and should only
   * be used through the normal accessor functions. The top bits of page->flags
   * and page->virtual store page management information, but all other fields
   * are unused and could be used privately, carefully. The management of this
   * page is the responsibility of the one who allocated it, and those who have
   * subsequently been given references to it.
   *
   * The other pages (we may call them "pagecache pages") are completely
   * managed by the Linux memory manager: I/O, buffers, swapping etc.
   * The following discussion applies only to them.
   *
   * A pagecache page contains an opaque `private' member, which belongs to the
   * page's address_space. Usually, this is the address of a circular list of
   * the page's disk buffers. PG_private must be set to tell the VM to call
   * into the filesystem to release these pages.
   *
   * A page may belong to an inode's memory mapping. In this case, page->mapping
   * is the pointer to the inode, and page->index is the file offset of the page,
   * in units of PAGE_CACHE_SIZE.
   *
   * If pagecache pages are not associated with an inode, they are said to be
   * anonymous pages. These may become associated with the swapcache, and in that
   * case PG_swapcache is set, and page->private is an offset into the swapcache.
   *
   * In either case (swapcache or inode backed), the pagecache itself holds one
   * reference to the page. Setting PG_private should also increment the
   * refcount. The each user mapping also has a reference to the page.
   *
   * The pagecache pages are stored in a per-mapping radix tree, which is
   * rooted at mapping->page_tree, and indexed by offset.
   * Where 2.4 and early 2.6 kernels kept dirty/clean pages in per-address_space
   * lists, we instead now tag pages as dirty/writeback in the radix tree.
   *
   * All pagecache pages may be subject to I/O:
   * - inode pages may need to be read from disk,
   * - inode pages which have been modified and are MAP_SHARED may need
   *   to be written back to the inode on disk,
   * - anonymous pages (including MAP_PRIVATE file mappings) which have been
   *   modified may need to be swapped out to swap space and (later) to be read
   *   back into memory.
   */
  
  /*
   * The zone field is never updated after free_area_init_core()
   * sets it, so none of the operations on it need to be atomic.
   */
  
  /* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_NID] | ... | FLAGS | */
  #define SECTIONS_PGOFF		((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
  #define NODES_PGOFF		(SECTIONS_PGOFF - NODES_WIDTH)
  #define ZONES_PGOFF		(NODES_PGOFF - ZONES_WIDTH)
  #define LAST_NID_PGOFF		(ZONES_PGOFF - LAST_NID_WIDTH)
  
  /*
   * Define the bit shifts to access each section.  For non-existent
   * sections we define the shift as 0; that plus a 0 mask ensures
   * the compiler will optimise away reference to them.
   */
  #define SECTIONS_PGSHIFT	(SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
  #define NODES_PGSHIFT		(NODES_PGOFF * (NODES_WIDTH != 0))
  #define ZONES_PGSHIFT		(ZONES_PGOFF * (ZONES_WIDTH != 0))
  #define LAST_NID_PGSHIFT	(LAST_NID_PGOFF * (LAST_NID_WIDTH != 0))
  
  /* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
  #ifdef NODE_NOT_IN_PAGE_FLAGS
  #define ZONEID_SHIFT		(SECTIONS_SHIFT + ZONES_SHIFT)
  #define ZONEID_PGOFF		((SECTIONS_PGOFF < ZONES_PGOFF)? \
  						SECTIONS_PGOFF : ZONES_PGOFF)
  #else
  #define ZONEID_SHIFT		(NODES_SHIFT + ZONES_SHIFT)
  #define ZONEID_PGOFF		((NODES_PGOFF < ZONES_PGOFF)? \
  						NODES_PGOFF : ZONES_PGOFF)
  #endif
  
  #define ZONEID_PGSHIFT		(ZONEID_PGOFF * (ZONEID_SHIFT != 0))
  
  #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
  #error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
  #endif
  
  #define ZONES_MASK		((1UL << ZONES_WIDTH) - 1)
  #define NODES_MASK		((1UL << NODES_WIDTH) - 1)
  #define SECTIONS_MASK		((1UL << SECTIONS_WIDTH) - 1)
  #define LAST_NID_MASK		((1UL << LAST_NID_WIDTH) - 1)
  #define ZONEID_MASK		((1UL << ZONEID_SHIFT) - 1)
  
  static inline enum zone_type page_zonenum(const struct page *page)
  {
  	return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
  }
  
  #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
  #define SECTION_IN_PAGE_FLAGS
  #endif
  
  /*
   * The identification function is only used by the buddy allocator for
   * determining if two pages could be buddies. We are not really
   * identifying a zone since we could be using a the section number
   * id if we have not node id available in page flags.
   * We guarantee only that it will return the same value for two
   * combinable pages in a zone.
   */
  static inline int page_zone_id(struct page *page)
  {
  	return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
  }
  
  static inline int zone_to_nid(struct zone *zone)
  {
  #ifdef CONFIG_NUMA
  	return zone->node;
  #else
  	return 0;
  #endif
  }
  
  #ifdef NODE_NOT_IN_PAGE_FLAGS
  extern int page_to_nid(const struct page *page);
  #else
  static inline int page_to_nid(const struct page *page)
  {
  	return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
  }
  #endif
  
  #ifdef CONFIG_NUMA_BALANCING
  #ifdef LAST_NID_NOT_IN_PAGE_FLAGS
  static inline int page_nid_xchg_last(struct page *page, int nid)
  {
  	return xchg(&page->_last_nid, nid);
  }
  
  static inline int page_nid_last(struct page *page)
  {
  	return page->_last_nid;
  }
  static inline void page_nid_reset_last(struct page *page)
  {
  	page->_last_nid = -1;
  }
  #else
  static inline int page_nid_last(struct page *page)
  {
  	return (page->flags >> LAST_NID_PGSHIFT) & LAST_NID_MASK;
  }
  
  extern int page_nid_xchg_last(struct page *page, int nid);
  
  static inline void page_nid_reset_last(struct page *page)
  {
  	int nid = (1 << LAST_NID_SHIFT) - 1;
  
  	page->flags &= ~(LAST_NID_MASK << LAST_NID_PGSHIFT);
  	page->flags |= (nid & LAST_NID_MASK) << LAST_NID_PGSHIFT;
  }
  #endif /* LAST_NID_NOT_IN_PAGE_FLAGS */
  #else
  static inline int page_nid_xchg_last(struct page *page, int nid)
  {
  	return page_to_nid(page);
  }
  
  static inline int page_nid_last(struct page *page)
  {
  	return page_to_nid(page);
  }
  
  static inline void page_nid_reset_last(struct page *page)
  {
  }
  #endif
  
  static inline struct zone *page_zone(const struct page *page)
  {
  	return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
  }
  
  #ifdef SECTION_IN_PAGE_FLAGS
  static inline void set_page_section(struct page *page, unsigned long section)
  {
  	page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
  	page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
  }
  
  static inline unsigned long page_to_section(const struct page *page)
  {
  	return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
  }
  #endif
  
  static inline void set_page_zone(struct page *page, enum zone_type zone)
  {
  	page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);
  	page->flags |= (zone & ZONES_MASK) << ZONES_PGSHIFT;
  }
  
  static inline void set_page_node(struct page *page, unsigned long node)
  {
  	page->flags &= ~(NODES_MASK << NODES_PGSHIFT);
  	page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
  }
  
  static inline void set_page_links(struct page *page, enum zone_type zone,
  	unsigned long node, unsigned long pfn)
  {
  	set_page_zone(page, zone);
  	set_page_node(page, node);
  #ifdef SECTION_IN_PAGE_FLAGS
  	set_page_section(page, pfn_to_section_nr(pfn));
  #endif
  }
  
  /*
   * Some inline functions in vmstat.h depend on page_zone()
   */
  #include <linux/vmstat.h>
  
  static __always_inline void *lowmem_page_address(const struct page *page)
  {
  	return __va(PFN_PHYS(page_to_pfn(page)));
  }
  
  #if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
  #define HASHED_PAGE_VIRTUAL
  #endif
  
  #if defined(WANT_PAGE_VIRTUAL)
  static inline void *page_address(const struct page *page)
  {
  	return page->virtual;
  }
  static inline void set_page_address(struct page *page, void *address)
  {
  	page->virtual = address;
  }
  #define page_address_init()  do { } while(0)
  #endif
  
  #if defined(HASHED_PAGE_VIRTUAL)
  void *page_address(const struct page *page);
  void set_page_address(struct page *page, void *virtual);
  void page_address_init(void);
  #endif
  
  #if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
  #define page_address(page) lowmem_page_address(page)
  #define set_page_address(page, address)  do { } while(0)
  #define page_address_init()  do { } while(0)
  #endif
  
  /*
   * On an anonymous page mapped into a user virtual memory area,
   * page->mapping points to its anon_vma, not to a struct address_space;
   * with the PAGE_MAPPING_ANON bit set to distinguish it.  See rmap.h.
   *
   * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
   * the PAGE_MAPPING_KSM bit may be set along with the PAGE_MAPPING_ANON bit;
   * and then page->mapping points, not to an anon_vma, but to a private
   * structure which KSM associates with that merged page.  See ksm.h.
   *
   * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is currently never used.
   *
   * Please note that, confusingly, "page_mapping" refers to the inode
   * address_space which maps the page from disk; whereas "page_mapped"
   * refers to user virtual address space into which the page is mapped.
   */
  #define PAGE_MAPPING_ANON	1
  #define PAGE_MAPPING_KSM	2
  #define PAGE_MAPPING_FLAGS	(PAGE_MAPPING_ANON | PAGE_MAPPING_KSM)
  
  extern struct address_space *page_mapping(struct page *page);
  
  /* Neutral page->mapping pointer to address_space or anon_vma or other */
  static inline void *page_rmapping(struct page *page)
  {
  	return (void *)((unsigned long)page->mapping & ~PAGE_MAPPING_FLAGS);
  }
  
  extern struct address_space *__page_file_mapping(struct page *);
  
  static inline
  struct address_space *page_file_mapping(struct page *page)
  {
  	if (unlikely(PageSwapCache(page)))
  		return __page_file_mapping(page);
  
  	return page->mapping;
  }
  
  static inline int PageAnon(struct page *page)
  {
  	return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
  }
  
  /*
   * Return the pagecache index of the passed page.  Regular pagecache pages
   * use ->index whereas swapcache pages use ->private
   */
  static inline pgoff_t page_index(struct page *page)
  {
  	if (unlikely(PageSwapCache(page)))
  		return page_private(page);
  	return page->index;
  }
  
  extern pgoff_t __page_file_index(struct page *page);
  
  /*
   * Return the file index of the page. Regular pagecache pages use ->index
   * whereas swapcache pages use swp_offset(->private)
   */
  static inline pgoff_t page_file_index(struct page *page)
  {
  	if (unlikely(PageSwapCache(page)))
  		return __page_file_index(page);
  
  	return page->index;
  }
  
  /*
   * Return true if this page is mapped into pagetables.
   */
  static inline int page_mapped(struct page *page)
  {
  	return atomic_read(&(page)->_mapcount) >= 0;
  }
  
  /*
   * Different kinds of faults, as returned by handle_mm_fault().
   * Used to decide whether a process gets delivered SIGBUS or
   * just gets major/minor fault counters bumped up.
   */
  
  #define VM_FAULT_MINOR	0 /* For backwards compat. Remove me quickly. */
  
  #define VM_FAULT_OOM	0x0001
  #define VM_FAULT_SIGBUS	0x0002
  #define VM_FAULT_MAJOR	0x0004
  #define VM_FAULT_WRITE	0x0008	/* Special case for get_user_pages */
  #define VM_FAULT_HWPOISON 0x0010	/* Hit poisoned small page */
  #define VM_FAULT_HWPOISON_LARGE 0x0020  /* Hit poisoned large page. Index encoded in upper bits */
  
  #define VM_FAULT_NOPAGE	0x0100	/* ->fault installed the pte, not return page */
  #define VM_FAULT_LOCKED	0x0200	/* ->fault locked the returned page */
  #define VM_FAULT_RETRY	0x0400	/* ->fault blocked, must retry */
  
  #define VM_FAULT_HWPOISON_LARGE_MASK 0xf000 /* encodes hpage index for large hwpoison */
  
  #define VM_FAULT_ERROR	(VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_HWPOISON | \
  			 VM_FAULT_HWPOISON_LARGE)
  
  /* Encode hstate index for a hwpoisoned large page */
  #define VM_FAULT_SET_HINDEX(x) ((x) << 12)
  #define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf)
  
  /*
   * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
   */
  extern void pagefault_out_of_memory(void);
  
  #define offset_in_page(p)	((unsigned long)(p) & ~PAGE_MASK)
  
  /*
   * Flags passed to show_mem() and show_free_areas() to suppress output in
   * various contexts.
   */
  #define SHOW_MEM_FILTER_NODES		(0x0001u)	/* disallowed nodes */
  #define SHOW_MEM_FILTER_PAGE_COUNT	(0x0002u)	/* page type count */
  
  extern void show_free_areas(unsigned int flags);
  extern bool skip_free_areas_node(unsigned int flags, int nid);
  
  void shmem_set_file(struct vm_area_struct *vma, struct file *file);
  int shmem_zero_setup(struct vm_area_struct *);
  
  extern int can_do_mlock(void);
  extern int user_shm_lock(size_t, struct user_struct *);
  extern void user_shm_unlock(size_t, struct user_struct *);
  
  /*
   * Parameter block passed down to zap_pte_range in exceptional cases.
   */
  struct zap_details {
  	struct vm_area_struct *nonlinear_vma;	/* Check page->index if set */
  	struct address_space *check_mapping;	/* Check page->mapping if set */
  	pgoff_t	first_index;			/* Lowest page->index to unmap */
  	pgoff_t last_index;			/* Highest page->index to unmap */
  };
  
  struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
  		pte_t pte);
  
  int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
  		unsigned long size);
  void zap_page_range(struct vm_area_struct *vma, unsigned long address,
  		unsigned long size, struct zap_details *);
  void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
  		unsigned long start, unsigned long end);
  
  /**
   * mm_walk - callbacks for walk_page_range
   * @pgd_entry: if set, called for each non-empty PGD (top-level) entry
   * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry
   * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
   *	       this handler is required to be able to handle
   *	       pmd_trans_huge() pmds.  They may simply choose to
   *	       split_huge_page() instead of handling it explicitly.
   * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
   * @pte_hole: if set, called for each hole at all levels
   * @hugetlb_entry: if set, called for each hugetlb entry
   *		   *Caution*: The caller must hold mmap_sem() if @hugetlb_entry
   * 			      is used.
   *
   * (see walk_page_range for more details)
   */
  struct mm_walk {
  	int (*pgd_entry)(pgd_t *pgd, unsigned long addr,
  			 unsigned long next, struct mm_walk *walk);
  	int (*pud_entry)(pud_t *pud, unsigned long addr,
  	                 unsigned long next, struct mm_walk *walk);
  	int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
  			 unsigned long next, struct mm_walk *walk);
  	int (*pte_entry)(pte_t *pte, unsigned long addr,
  			 unsigned long next, struct mm_walk *walk);
  	int (*pte_hole)(unsigned long addr, unsigned long next,
  			struct mm_walk *walk);
  	int (*hugetlb_entry)(pte_t *pte, unsigned long hmask,
  			     unsigned long addr, unsigned long next,
  			     struct mm_walk *walk);
  	struct mm_struct *mm;
  	void *private;
  };
  
  int walk_page_range(unsigned long addr, unsigned long end,
  		struct mm_walk *walk);
  void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
  		unsigned long end, unsigned long floor, unsigned long ceiling);
  int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
  			struct vm_area_struct *vma);
  void unmap_mapping_range(struct address_space *mapping,
  		loff_t const holebegin, loff_t const holelen, int even_cows);
  int follow_pfn(struct vm_area_struct *vma, unsigned long address,
  	unsigned long *pfn);
  int follow_phys(struct vm_area_struct *vma, unsigned long address,
  		unsigned int flags, unsigned long *prot, resource_size_t *phys);
  int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
  			void *buf, int len, int write);
  
  static inline void unmap_shared_mapping_range(struct address_space *mapping,
  		loff_t const holebegin, loff_t const holelen)
  {
  	unmap_mapping_range(mapping, holebegin, holelen, 0);
  }
  
  extern void truncate_pagecache(struct inode *inode, loff_t old, loff_t new);
  extern void truncate_setsize(struct inode *inode, loff_t newsize);
  void truncate_pagecache_range(struct inode *inode, loff_t offset, loff_t end);
  int truncate_inode_page(struct address_space *mapping, struct page *page);
  int generic_error_remove_page(struct address_space *mapping, struct page *page);
  int invalidate_inode_page(struct page *page);
  
  #ifdef CONFIG_MMU
  extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
  			unsigned long address, unsigned int flags);
  extern int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
  			    unsigned long address, unsigned int fault_flags);
  #else
  static inline int handle_mm_fault(struct mm_struct *mm,
  			struct vm_area_struct *vma, unsigned long address,
  			unsigned int flags)
  {
  	/* should never happen if there's no MMU */
  	BUG();
  	return VM_FAULT_SIGBUS;
  }
  static inline int fixup_user_fault(struct task_struct *tsk,
  		struct mm_struct *mm, unsigned long address,
  		unsigned int fault_flags)
  {
  	/* should never happen if there's no MMU */
  	BUG();
  	return -EFAULT;
  }
  #endif
  
  extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
  extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
  		void *buf, int len, int write);
  
  long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
  		      unsigned long start, unsigned long nr_pages,
  		      unsigned int foll_flags, struct page **pages,
  		      struct vm_area_struct **vmas, int *nonblocking);
  long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
  		    unsigned long start, unsigned long nr_pages,
  		    int write, int force, struct page **pages,
  		    struct vm_area_struct **vmas);
  int get_user_pages_fast(unsigned long start, int nr_pages, int write,
  			struct page **pages);
  struct kvec;
  int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
  			struct page **pages);
  int get_kernel_page(unsigned long start, int write, struct page **pages);
  struct page *get_dump_page(unsigned long addr);
  
  extern int try_to_release_page(struct page * page, gfp_t gfp_mask);
  extern void do_invalidatepage(struct page *page, unsigned long offset);
  
  int __set_page_dirty_nobuffers(struct page *page);
  int __set_page_dirty_no_writeback(struct page *page);
  int redirty_page_for_writepage(struct writeback_control *wbc,
  				struct page *page);
  void account_page_dirtied(struct page *page, struct address_space *mapping);
  void account_page_writeback(struct page *page);
  int set_page_dirty(struct page *page);
  int set_page_dirty_lock(struct page *page);
  int clear_page_dirty_for_io(struct page *page);
  int get_cmdline(struct task_struct *task, char *buffer, int buflen);
  
  extern pid_t
  vm_is_stack(struct task_struct *task, struct vm_area_struct *vma, int in_group);
  
  extern unsigned long move_page_tables(struct vm_area_struct *vma,
  		unsigned long old_addr, struct vm_area_struct *new_vma,
  		unsigned long new_addr, unsigned long len,
  		bool need_rmap_locks);
  extern unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
  			      unsigned long end, pgprot_t newprot,
  			      int dirty_accountable, int prot_numa);
  extern int mprotect_fixup(struct vm_area_struct *vma,
  			  struct vm_area_struct **pprev, unsigned long start,
  			  unsigned long end, unsigned long newflags);
  
  /*
   * doesn't attempt to fault and will return short.
   */
  int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
  			  struct page **pages);
  /*
   * per-process(per-mm_struct) statistics.
   */
  static inline unsigned long get_mm_counter(struct mm_struct *mm, int member)
  {
  	long val = atomic_long_read(&mm->rss_stat.count[member]);
  
  #ifdef SPLIT_RSS_COUNTING
  	/*
  	 * counter is updated in asynchronous manner and may go to minus.
  	 * But it's never be expected number for users.
  	 */
  	if (val < 0)
  		val = 0;
  #endif
  	return (unsigned long)val;
  }
  
  static inline void add_mm_counter(struct mm_struct *mm, int member, long value)
  {
  	atomic_long_add(value, &mm->rss_stat.count[member]);
  }
  
  static inline void inc_mm_counter(struct mm_struct *mm, int member)
  {
  	atomic_long_inc(&mm->rss_stat.count[member]);
  }
  
  static inline void dec_mm_counter(struct mm_struct *mm, int member)
  {
  	atomic_long_dec(&mm->rss_stat.count[member]);
  }
  
  static inline unsigned long get_mm_rss(struct mm_struct *mm)
  {
  	return get_mm_counter(mm, MM_FILEPAGES) +
  		get_mm_counter(mm, MM_ANONPAGES);
  }
  
  static inline unsigned long get_mm_hiwater_rss(struct mm_struct *mm)
  {
  	return max(mm->hiwater_rss, get_mm_rss(mm));
  }
  
  static inline unsigned long get_mm_hiwater_vm(struct mm_struct *mm)
  {
  	return max(mm->hiwater_vm, mm->total_vm);
  }
  
  static inline void update_hiwater_rss(struct mm_struct *mm)
  {
  	unsigned long _rss = get_mm_rss(mm);
  
  	if ((mm)->hiwater_rss < _rss)
  		(mm)->hiwater_rss = _rss;
  }
  
  static inline void update_hiwater_vm(struct mm_struct *mm)
  {
  	if (mm->hiwater_vm < mm->total_vm)
  		mm->hiwater_vm = mm->total_vm;
  }
  
  static inline void setmax_mm_hiwater_rss(unsigned long *maxrss,
  					 struct mm_struct *mm)
  {
  	unsigned long hiwater_rss = get_mm_hiwater_rss(mm);
  
  	if (*maxrss < hiwater_rss)
  		*maxrss = hiwater_rss;
  }
  
  #if defined(SPLIT_RSS_COUNTING)
  void sync_mm_rss(struct mm_struct *mm);
  #else
  static inline void sync_mm_rss(struct mm_struct *mm)
  {
  }
  #endif
  
  int vma_wants_writenotify(struct vm_area_struct *vma);
  
  extern pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
  			       spinlock_t **ptl);
  static inline pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
  				    spinlock_t **ptl)
  {
  	pte_t *ptep;
  	__cond_lock(*ptl, ptep = __get_locked_pte(mm, addr, ptl));
  	return ptep;
  }
  
  #ifdef __PAGETABLE_PUD_FOLDED
  static inline int __pud_alloc(struct mm_struct *mm, pgd_t *pgd,
  						unsigned long address)
  {
  	return 0;
  }
  #else
  int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
  #endif
  
  #ifdef __PAGETABLE_PMD_FOLDED
  static inline int __pmd_alloc(struct mm_struct *mm, pud_t *pud,
  						unsigned long address)
  {
  	return 0;
  }
  #else
  int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
  #endif
  
  int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
  		pmd_t *pmd, unsigned long address);
  int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);
  
  /*
   * The following ifdef needed to get the 4level-fixup.h header to work.
   * Remove it when 4level-fixup.h has been removed.
   */
  #if defined(CONFIG_MMU) && !defined(__ARCH_HAS_4LEVEL_HACK)
  static inline pud_t *pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
  {
  	return (unlikely(pgd_none(*pgd)) && __pud_alloc(mm, pgd, address))?
  		NULL: pud_offset(pgd, address);
  }
  
  static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
  {
  	return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
  		NULL: pmd_offset(pud, address);
  }
  #endif /* CONFIG_MMU && !__ARCH_HAS_4LEVEL_HACK */
  
  #if USE_SPLIT_PTLOCKS
  /*
   * We tuck a spinlock to guard each pagetable page into its struct page,
   * at page->private, with BUILD_BUG_ON to make sure that this will not
   * overflow into the next struct page (as it might with DEBUG_SPINLOCK).
   * When freeing, reset page->mapping so free_pages_check won't complain.
   */
  #define __pte_lockptr(page)	&((page)->ptl)
  #define pte_lock_init(_page)	do {					\
  	spin_lock_init(__pte_lockptr(_page));				\
  } while (0)
  #define pte_lock_deinit(page)	((page)->mapping = NULL)
  #define pte_lockptr(mm, pmd)	({(void)(mm); __pte_lockptr(pmd_page(*(pmd)));})
  #else	/* !USE_SPLIT_PTLOCKS */
  /*
   * We use mm->page_table_lock to guard all pagetable pages of the mm.
   */
  #define pte_lock_init(page)	do {} while (0)
  #define pte_lock_deinit(page)	do {} while (0)
  #define pte_lockptr(mm, pmd)	({(void)(pmd); &(mm)->page_table_lock;})
  #endif /* USE_SPLIT_PTLOCKS */
  
  static inline bool pgtable_page_ctor(struct page *page)
  {
  	pte_lock_init(page);
  	inc_zone_page_state(page, NR_PAGETABLE);
  	return true;
  }
  
  static inline void pgtable_page_dtor(struct page *page)
  {
  	pte_lock_deinit(page);
  	dec_zone_page_state(page, NR_PAGETABLE);
  }
  
  #define pte_offset_map_lock(mm, pmd, address, ptlp)	\
  ({							\
  	spinlock_t *__ptl = pte_lockptr(mm, pmd);	\
  	pte_t *__pte = pte_offset_map(pmd, address);	\
  	*(ptlp) = __ptl;				\
  	spin_lock(__ptl);				\
  	__pte;						\
  })
  
  #define pte_unmap_unlock(pte, ptl)	do {		\
  	spin_unlock(ptl);				\
  	pte_unmap(pte);					\
  } while (0)
  
  #define pte_alloc_map(mm, vma, pmd, address)				\
  	((unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, vma,	\
  							pmd, address))?	\
  	 NULL: pte_offset_map(pmd, address))
  
  #define pte_alloc_map_lock(mm, pmd, address, ptlp)	\
  	((unlikely(pmd_none(*(pmd))) && __pte_alloc(mm, NULL,	\
  							pmd, address))?	\
  		NULL: pte_offset_map_lock(mm, pmd, address, ptlp))
  
  #define pte_alloc_kernel(pmd, address)			\
  	((unlikely(pmd_none(*(pmd))) && __pte_alloc_kernel(pmd, address))? \
  		NULL: pte_offset_kernel(pmd, address))
  
  extern void free_area_init(unsigned long * zones_size);
  extern void free_area_init_node(int nid, unsigned long * zones_size,
  		unsigned long zone_start_pfn, unsigned long *zholes_size);
  extern void free_initmem(void);
  
  /*
   * Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
   * into the buddy system. The freed pages will be poisoned with pattern
   * "poison" if it's non-zero.
   * Return pages freed into the buddy system.
   */
  extern unsigned long free_reserved_area(unsigned long start, unsigned long end,
  					int poison, char *s);
  
  #ifdef	CONFIG_HIGHMEM
  /*
   * Free a highmem page into the buddy system, adjusting totalhigh_pages
   * and totalram_pages.
   */
  extern void free_highmem_page(struct page *page);
  #endif
  
  extern void adjust_managed_page_count(struct page *page, long count);
  extern void mem_init_print_info(const char *str);
  
  /* Free the reserved page into the buddy system, so it gets managed. */
  static inline void __free_reserved_page(struct page *page)
  {
  	ClearPageReserved(page);
  	init_page_count(page);
  	__free_page(page);
  }
  
  static inline void free_reserved_page(struct page *page)
  {
  	__free_reserved_page(page);
  	adjust_managed_page_count(page, 1);
  }
  
  static inline void mark_page_reserved(struct page *page)
  {
  	SetPageReserved(page);
  	adjust_managed_page_count(page, -1);
  }
  
  /*
   * Default method to free all the __init memory into the buddy system.
   * The freed pages will be poisoned with pattern "poison" if it is
   * non-zero. Return pages freed into the buddy system.
   */
  static inline unsigned long free_initmem_default(int poison)
  {
  	extern char __init_begin[], __init_end[];
  
  	return free_reserved_area(PAGE_ALIGN((unsigned long)&__init_begin) ,
  				  ((unsigned long)&__init_end) & PAGE_MASK,
  				  poison, "unused kernel");
  }
  
  static inline unsigned long get_num_physpages(void)
  {
  	int nid;
  	unsigned long phys_pages = 0;
  
  	for_each_online_node(nid)
  		phys_pages += node_present_pages(nid);
  
  	return phys_pages;
  }
  
  #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
  /*
   * With CONFIG_HAVE_MEMBLOCK_NODE_MAP set, an architecture may initialise its
   * zones, allocate the backing mem_map and account for memory holes in a more
   * architecture independent manner. This is a substitute for creating the
   * zone_sizes[] and zholes_size[] arrays and passing them to
   * free_area_init_node()
   *
   * An architecture is expected to register range of page frames backed by
   * physical memory with memblock_add[_node]() before calling
   * free_area_init_nodes() passing in the PFN each zone ends at. At a basic
   * usage, an architecture is expected to do something like
   *
   * unsigned long max_zone_pfns[MAX_NR_ZONES] = {max_dma, max_normal_pfn,
   * 							 max_highmem_pfn};
   * for_each_valid_physical_page_range()
   * 	memblock_add_node(base, size, nid)
   * free_area_init_nodes(max_zone_pfns);
   *
   * free_bootmem_with_active_regions() calls free_bootmem_node() for each
   * registered physical page range.  Similarly
   * sparse_memory_present_with_active_regions() calls memory_present() for
   * each range when SPARSEMEM is enabled.
   *
   * See mm/page_alloc.c for more information on each function exposed by
   * CONFIG_HAVE_MEMBLOCK_NODE_MAP.
   */
  extern void free_area_init_nodes(unsigned long *max_zone_pfn);
  unsigned long node_map_pfn_alignment(void);
  unsigned long __absent_pages_in_range(int nid, unsigned long start_pfn,
  						unsigned long end_pfn);
  extern unsigned long absent_pages_in_range(unsigned long start_pfn,
  						unsigned long end_pfn);
  extern void get_pfn_range_for_nid(unsigned int nid,
  			unsigned long *start_pfn, unsigned long *end_pfn);
  extern unsigned long find_min_pfn_with_active_regions(void);
  extern void free_bootmem_with_active_regions(int nid,
  						unsigned long max_low_pfn);
  extern void sparse_memory_present_with_active_regions(int nid);
  
  #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
  
  #if !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && \
      !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID)
  static inline int __early_pfn_to_nid(unsigned long pfn)
  {
  	return 0;
  }
  #else
  /* please see mm/page_alloc.c */
  extern int __meminit early_pfn_to_nid(unsigned long pfn);
  #ifdef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
  /* there is a per-arch backend function. */
  extern int __meminit __early_pfn_to_nid(unsigned long pfn);
  #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
  #endif
  
  extern void set_dma_reserve(unsigned long new_dma_reserve);
  extern void memmap_init_zone(unsigned long, int, unsigned long,
  				unsigned long, enum memmap_context);
  extern void setup_per_zone_wmarks(void);
  extern int __meminit init_per_zone_wmark_min(void);
  extern void mem_init(void);
  extern void __init mmap_init(void);
  extern void show_mem(unsigned int flags);
  extern void si_meminfo(struct sysinfo * val);
  extern void si_meminfo_node(struct sysinfo *val, int nid);
  
  extern __printf(3, 4)
  void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...);
  
  extern void setup_per_cpu_pageset(void);
  
  extern void zone_pcp_update(struct zone *zone);
  extern void zone_pcp_reset(struct zone *zone);
  
  /* page_alloc.c */
  extern int min_free_kbytes;
  
  /* nommu.c */
  extern atomic_long_t mmap_pages_allocated;
  extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
  
  /* interval_tree.c */
  void vma_interval_tree_insert(struct vm_area_struct *node,
  			      struct rb_root *root);
  void vma_interval_tree_insert_after(struct vm_area_struct *node,
  				    struct vm_area_struct *prev,
  				    struct rb_root *root);
  void vma_interval_tree_remove(struct vm_area_struct *node,
  			      struct rb_root *root);
  struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root *root,
  				unsigned long start, unsigned long last);
  struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
  				unsigned long start, unsigned long last);
  
  #define vma_interval_tree_foreach(vma, root, start, last)		\
  	for (vma = vma_interval_tree_iter_first(root, start, last);	\
  	     vma; vma = vma_interval_tree_iter_next(vma, start, last))
  
  static inline void vma_nonlinear_insert(struct vm_area_struct *vma,
  					struct list_head *list)
  {
  	list_add_tail(&vma->shared.nonlinear, list);
  }
  
  void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
  				   struct rb_root *root);
  void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
  				   struct rb_root *root);
  struct anon_vma_chain *anon_vma_interval_tree_iter_first(
  	struct rb_root *root, unsigned long start, unsigned long last);
  struct anon_vma_chain *anon_vma_interval_tree_iter_next(
  	struct anon_vma_chain *node, unsigned long start, unsigned long last);
  #ifdef CONFIG_DEBUG_VM_RB
  void anon_vma_interval_tree_verify(struct anon_vma_chain *node);
  #endif
  
  #define anon_vma_interval_tree_foreach(avc, root, start, last)		 \
  	for (avc = anon_vma_interval_tree_iter_first(root, start, last); \
  	     avc; avc = anon_vma_interval_tree_iter_next(avc, start, last))
  
  /* mmap.c */
  extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
  extern int vma_adjust(struct vm_area_struct *vma, unsigned long start,
  	unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert);
  extern struct vm_area_struct *vma_merge(struct mm_struct *,
  	struct vm_area_struct *prev, unsigned long addr, unsigned long end,
  	unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
  	struct mempolicy *, const char __user *);
  extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
  extern int split_vma(struct mm_struct *,
  	struct vm_area_struct *, unsigned long addr, int new_below);
  extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
  extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
  	struct rb_node **, struct rb_node *);
  extern void unlink_file_vma(struct vm_area_struct *);
  extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
  	unsigned long addr, unsigned long len, pgoff_t pgoff,
  	bool *need_rmap_locks);
  extern void exit_mmap(struct mm_struct *);
  
  extern int mm_take_all_locks(struct mm_struct *mm);
  extern void mm_drop_all_locks(struct mm_struct *mm);
  
  extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
  extern struct file *get_mm_exe_file(struct mm_struct *mm);
  
  extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
  extern int install_special_mapping(struct mm_struct *mm,
  				   unsigned long addr, unsigned long len,
  				   unsigned long flags, struct page **pages);
  
  extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
  
  extern unsigned long mmap_region(struct file *file, unsigned long addr,
  	unsigned long len, vm_flags_t vm_flags, unsigned long pgoff);
  extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
  	unsigned long len, unsigned long prot, unsigned long flags,
  	unsigned long pgoff, unsigned long *populate);
  extern int do_munmap(struct mm_struct *, unsigned long, size_t);
  
  #ifdef CONFIG_MMU
  extern int __mm_populate(unsigned long addr, unsigned long len,
  			 int ignore_errors);
  static inline void mm_populate(unsigned long addr, unsigned long len)
  {
  	/* Ignore errors */
  	(void) __mm_populate(addr, len, 1);
  }
  #else
  static inline void mm_populate(unsigned long addr, unsigned long len) {}
  #endif
  
  /* These take the mm semaphore themselves */
  extern unsigned long vm_brk(unsigned long, unsigned long);
  extern int vm_munmap(unsigned long, size_t);
  extern unsigned long vm_mmap(struct file *, unsigned long,
          unsigned long, unsigned long,
          unsigned long, unsigned long);
  
  struct vm_unmapped_area_info {
  #define VM_UNMAPPED_AREA_TOPDOWN 1
  	unsigned long flags;
  	unsigned long length;
  	unsigned long low_limit;
  	unsigned long high_limit;
  	unsigned long align_mask;
  	unsigned long align_offset;
  };
  
  extern unsigned long unmapped_area(struct vm_unmapped_area_info *info);
  extern unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info);
  
  /*
   * Search for an unmapped address range.
   *
   * We are looking for a range that:
   * - does not intersect with any VMA;
   * - is contained within the [low_limit, high_limit) interval;
   * - is at least the desired size.
   * - satisfies (begin_addr & align_mask) == (align_offset & align_mask)
   */
  static inline unsigned long
  vm_unmapped_area(struct vm_unmapped_area_info *info)
  {
  	if (!(info->flags & VM_UNMAPPED_AREA_TOPDOWN))
  		return unmapped_area(info);
  	else
  		return unmapped_area_topdown(info);
  }
  
  /* truncate.c */
  extern void truncate_inode_pages(struct address_space *, loff_t);
  extern void truncate_inode_pages_range(struct address_space *,
  				       loff_t lstart, loff_t lend);
  
  /* generic vm_area_ops exported for stackable file systems */
  extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);
  extern int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
  
  /* mm/page-writeback.c */
  int write_one_page(struct page *page, int wait);
  void task_dirty_inc(struct task_struct *tsk);
  
  /* readahead.c */
  #define VM_MAX_READAHEAD	512	/* kbytes */
  #define VM_MIN_READAHEAD	16	/* kbytes (includes current page) */
  
  int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
  			pgoff_t offset, unsigned long nr_to_read);
  
  void page_cache_sync_readahead(struct address_space *mapping,
  			       struct file_ra_state *ra,
  			       struct file *filp,
  			       pgoff_t offset,
  			       unsigned long size);
  
  void page_cache_async_readahead(struct address_space *mapping,
  				struct file_ra_state *ra,
  				struct file *filp,
  				struct page *pg,
  				pgoff_t offset,
  				unsigned long size);
  
  unsigned long max_sane_readahead(unsigned long nr);
  unsigned long ra_submit(struct file_ra_state *ra,
  			struct address_space *mapping,
  			struct file *filp);
  
  extern unsigned long stack_guard_gap;
  
  /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
  extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
  
  /* CONFIG_STACK_GROWSUP still needs to to grow downwards at some places */
  extern int expand_downwards(struct vm_area_struct *vma,
  		unsigned long address);
  #if VM_GROWSUP
  extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
  #else
    #define expand_upwards(vma, address) do { } while (0)
  #endif
  
  /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
  extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
  extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
  					     struct vm_area_struct **pprev);
  
  /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
     NULL if none.  Assume start_addr < end_addr. */
  static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
  {
  	struct vm_area_struct * vma = find_vma(mm,start_addr);
  
  	if (vma && end_addr <= vma->vm_start)
  		vma = NULL;
  	return vma;
  }
  
  static inline unsigned long vm_start_gap(struct vm_area_struct *vma)
  {
  	unsigned long vm_start = vma->vm_start;
  
  	if (vma->vm_flags & VM_GROWSDOWN) {
  		vm_start -= stack_guard_gap;
  		if (vm_start > vma->vm_start)
  			vm_start = 0;
  	}
  	return vm_start;
  }
  
  static inline unsigned long vm_end_gap(struct vm_area_struct *vma)
  {
  	unsigned long vm_end = vma->vm_end;
  
  	if (vma->vm_flags & VM_GROWSUP) {
  		vm_end += stack_guard_gap;
  		if (vm_end < vma->vm_end)
  			vm_end = -PAGE_SIZE;
  	}
  	return vm_end;
  }
  
  static inline unsigned long vma_pages(struct vm_area_struct *vma)
  {
  	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
  }
  
  /* Look up the first VMA which exactly match the interval vm_start ... vm_end */
  static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
  				unsigned long vm_start, unsigned long vm_end)
  {
  	struct vm_area_struct *vma = find_vma(mm, vm_start);
  
  	if (vma && (vma->vm_start != vm_start || vma->vm_end != vm_end))
  		vma = NULL;
  
  	return vma;
  }
  
  #ifdef CONFIG_MMU
  pgprot_t vm_get_page_prot(unsigned long vm_flags);
  #else
  static inline pgprot_t vm_get_page_prot(unsigned long vm_flags)
  {
  	return __pgprot(0);
  }
  #endif
  
  #ifdef CONFIG_ARCH_USES_NUMA_PROT_NONE
  unsigned long change_prot_numa(struct vm_area_struct *vma,
  			unsigned long start, unsigned long end);
  #endif
  
  struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
  int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
  			unsigned long pfn, unsigned long size, pgprot_t);
  int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
  int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
  			unsigned long pfn);
  int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
  			unsigned long pfn);
  int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len);
  
  
  struct page *follow_page_mask(struct vm_area_struct *vma,
  			      unsigned long address, unsigned int foll_flags,
  			      unsigned int *page_mask);
  
  static inline struct page *follow_page(struct vm_area_struct *vma,
  		unsigned long address, unsigned int foll_flags)
  {
  	unsigned int unused_page_mask;
  	return follow_page_mask(vma, address, foll_flags, &unused_page_mask);
  }
  
  #define FOLL_WRITE	0x01	/* check pte is writable */
  #define FOLL_TOUCH	0x02	/* mark page accessed */
  #define FOLL_GET	0x04	/* do get_page on page */
  #define FOLL_DUMP	0x08	/* give error on hole if it would be zero */
  #define FOLL_FORCE	0x10	/* get_user_pages read/write w/o permission */
  #define FOLL_NOWAIT	0x20	/* if a disk transfer is needed, start the IO
  				 * and return without waiting upon it */
  #define FOLL_MLOCK	0x40	/* mark page as mlocked */
  #define FOLL_SPLIT	0x80	/* don't return transhuge pages, split them */
  #define FOLL_HWPOISON	0x100	/* check page is hwpoisoned */
  #define FOLL_NUMA	0x200	/* force NUMA hinting page fault */
  #define FOLL_MIGRATION	0x400	/* wait for page to replace migration entry */
  #define FOLL_COW	0x4000	/* internal GUP flag */
  #define FOLL_CMA	0x80000	/* migrate if the page is from cma pageblock */
  
  typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
  			void *data);
  extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
  			       unsigned long size, pte_fn_t fn, void *data);
  
  #ifdef CONFIG_PROC_FS
  void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long);
  #else
  static inline void vm_stat_account(struct mm_struct *mm,
  			unsigned long flags, struct file *file, long pages)
  {
  	mm->total_vm += pages;
  }
  #endif /* CONFIG_PROC_FS */
  
  #ifdef CONFIG_DEBUG_PAGEALLOC
  extern void kernel_map_pages(struct page *page, int numpages, int enable);
  #ifdef CONFIG_HIBERNATION
  extern bool kernel_page_present(struct page *page);
  #endif /* CONFIG_HIBERNATION */
  #else
  static inline void
  kernel_map_pages(struct page *page, int numpages, int enable) {}
  #ifdef CONFIG_HIBERNATION
  static inline bool kernel_page_present(struct page *page) { return true; }
  #endif /* CONFIG_HIBERNATION */
  #endif
  
  extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
  #ifdef	__HAVE_ARCH_GATE_AREA
  int in_gate_area_no_mm(unsigned long addr);
  int in_gate_area(struct mm_struct *mm, unsigned long addr);
  #else
  int in_gate_area_no_mm(unsigned long addr);
  #define in_gate_area(mm, addr) ({(void)mm; in_gate_area_no_mm(addr);})
  #endif	/* __HAVE_ARCH_GATE_AREA */
  
  #ifdef CONFIG_USE_USER_ACCESSIBLE_TIMERS
  static inline int use_user_accessible_timers(void) { return 1; }
  extern int in_user_timers_area(struct mm_struct *mm, unsigned long addr);
  extern struct vm_area_struct *get_user_timers_vma(struct mm_struct *mm);
  extern int get_user_timer_page(struct vm_area_struct *vma,
  	struct mm_struct *mm, unsigned long start, unsigned int gup_flags,
  	struct page **pages, int idx, int *goto_next_page);
  #else
  static inline int use_user_accessible_timers(void) { return 0; }
  static inline int in_user_timers_area(struct mm_struct *mm, unsigned long addr)
  {
  	return 0;
  }
  static inline struct vm_area_struct *get_user_timers_vma(struct mm_struct *mm)
  {
  	return NULL;
  }
  static inline int get_user_timer_page(struct vm_area_struct *vma,
  	struct mm_struct *mm, unsigned long start, unsigned int gup_flags,
  	struct page **pages, int idx, int *goto_next_page)
  {
  	*goto_next_page = 0;
  	return 0;
  }
  #endif
  
  #ifdef CONFIG_SYSCTL
  extern int sysctl_drop_caches;
  int drop_caches_sysctl_handler(struct ctl_table *, int,
  					void __user *, size_t *, loff_t *);
  #endif
  
  unsigned long shrink_slab(struct shrink_control *shrink,
  			  unsigned long nr_pages_scanned,
  			  unsigned long lru_pages);
  
  #ifndef CONFIG_MMU
  #define randomize_va_space 0
  #else
  extern int randomize_va_space;
  #endif
  
  const char * arch_vma_name(struct vm_area_struct *vma);
  void print_vma_addr(char *prefix, unsigned long rip);
  
  void sparse_mem_maps_populate_node(struct page **map_map,
  				   unsigned long pnum_begin,
  				   unsigned long pnum_end,
  				   unsigned long map_count,
  				   int nodeid);
  
  struct page *sparse_mem_map_populate(unsigned long pnum, int nid);
  pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
  pud_t *vmemmap_pud_populate(pgd_t *pgd, unsigned long addr, int node);
  pmd_t *vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node);
  pte_t *vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node);
  void *vmemmap_alloc_block(unsigned long size, int node);
  void *vmemmap_alloc_block_buf(unsigned long size, int node);
  void vmemmap_verify(pte_t *, int, unsigned long, unsigned long);
  int vmemmap_populate_basepages(unsigned long start, unsigned long end,
  			       int node);
  int vmemmap_populate(unsigned long start, unsigned long end, int node);
  void vmemmap_populate_print_last(void);
  #ifdef CONFIG_MEMORY_HOTPLUG
  void vmemmap_free(unsigned long start, unsigned long end);
  #endif
  void register_page_bootmem_memmap(unsigned long section_nr, struct page *map,
  				  unsigned long size);
  
  enum mf_flags {
  	MF_COUNT_INCREASED = 1 << 0,
  	MF_ACTION_REQUIRED = 1 << 1,
  	MF_MUST_KILL = 1 << 2,
  };
  extern int memory_failure(unsigned long pfn, int trapno, int flags);
  extern void memory_failure_queue(unsigned long pfn, int trapno, int flags);
  extern int unpoison_memory(unsigned long pfn);
  extern int sysctl_memory_failure_early_kill;
  extern int sysctl_memory_failure_recovery;
  extern void shake_page(struct page *p, int access);
  extern atomic_long_t num_poisoned_pages;
  extern int soft_offline_page(struct page *page, int flags);
  
  extern void dump_page(struct page *page);
  
  #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
  extern void clear_huge_page(struct page *page,
  			    unsigned long addr,
  			    unsigned int pages_per_huge_page);
  extern void copy_user_huge_page(struct page *dst, struct page *src,
  				unsigned long addr, struct vm_area_struct *vma,
  				unsigned int pages_per_huge_page);
  #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
  
  #ifdef CONFIG_DEBUG_PAGEALLOC
  extern unsigned int _debug_guardpage_minorder;
  
  static inline unsigned int debug_guardpage_minorder(void)
  {
  	return _debug_guardpage_minorder;
  }
  
  static inline bool page_is_guard(struct page *page)
  {
  	return test_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
  }
  #else
  static inline unsigned int debug_guardpage_minorder(void) { return 0; }
  static inline bool page_is_guard(struct page *page) { return false; }
  #endif /* CONFIG_DEBUG_PAGEALLOC */
  
  #if MAX_NUMNODES > 1
  void __init setup_nr_node_ids(void);
  #else
  static inline void setup_nr_node_ids(void) {}
  #endif
  
  #ifdef CONFIG_PROCESS_RECLAIM
  struct reclaim_param {
  	struct vm_area_struct *vma;
  	/* Number of pages scanned */
  	int nr_scanned;
  	/* max pages to reclaim */
  	int nr_to_reclaim;
  	/* pages reclaimed */
  	int nr_reclaimed;
  };
  extern struct reclaim_param reclaim_task_anon(struct task_struct *task,
  		int nr_to_reclaim);
  #endif
  
  #endif /* __KERNEL__ */
  #endif /* _LINUX_MM_H */
  