Cross-Referenced Linux and Device Driver Code

   /*
    *  linux/mm/page_alloc.c
    *
    *  Manages the free list, the system allocates free pages here.
    *  Note that kmalloc() lives in slab.c
    *
    *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
    *  Swap reorganised 29.12.95, Stephen Tweedie
    *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
   *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
   *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
   *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
   *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
   *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
   */
  
  #include <linux/stddef.h>
  #include <linux/mm.h>
  #include <linux/swap.h>
  #include <linux/interrupt.h>
  #include <linux/pagemap.h>
  #include <linux/jiffies.h>
  #include <linux/bootmem.h>
  #include <linux/compiler.h>
  #include <linux/kernel.h>
  #include <linux/kmemcheck.h>
  #include <linux/module.h>
  #include <linux/suspend.h>
  #include <linux/pagevec.h>
  #include <linux/blkdev.h>
  #include <linux/slab.h>
  #include <linux/oom.h>
  #include <linux/notifier.h>
  #include <linux/topology.h>
  #include <linux/sysctl.h>
  #include <linux/cpu.h>
  #include <linux/cpuset.h>
  #include <linux/memory_hotplug.h>
  #include <linux/nodemask.h>
  #include <linux/vmalloc.h>
  #include <linux/mempolicy.h>
  #include <linux/stop_machine.h>
  #include <linux/sort.h>
  #include <linux/pfn.h>
  #include <linux/backing-dev.h>
  #include <linux/fault-inject.h>
  #include <linux/page-isolation.h>
  #include <linux/page_cgroup.h>
  #include <linux/debugobjects.h>
  #include <linux/kmemleak.h>
  
  #include <asm/tlbflush.h>
  #include <asm/div64.h>
  #include "internal.h"
  
  /*
   * Array of node states.
   */
  nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
          [N_POSSIBLE] = NODE_MASK_ALL,
          [N_ONLINE] = { { [0] = 1UL } },
  #ifndef CONFIG_NUMA
          [N_NORMAL_MEMORY] = { { [0] = 1UL } },
  #ifdef CONFIG_HIGHMEM
          [N_HIGH_MEMORY] = { { [0] = 1UL } },
  #endif
          [N_CPU] = { { [0] = 1UL } },
  #endif  /* NUMA */
  };
  EXPORT_SYMBOL(node_states);
  
  unsigned long totalram_pages __read_mostly;
  unsigned long totalreserve_pages __read_mostly;
  unsigned long highest_memmap_pfn __read_mostly;
  int percpu_pagelist_fraction;
  gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
  
  #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
  int pageblock_order __read_mostly;
  #endif
  
  static void __free_pages_ok(struct page *page, unsigned int order);
  
  /*
   * results with 256, 32 in the lowmem_reserve sysctl:
   *      1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
   *      1G machine -> (16M dma, 784M normal, 224M high)
   *      NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
   *      HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
   *      HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
   *
   * TBD: should special case ZONE_DMA32 machines here - in those we normally
   * don't need any ZONE_NORMAL reservation
   */
  int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
  #ifdef CONFIG_ZONE_DMA
           256,
  #endif
  #ifdef CONFIG_ZONE_DMA32
          256,
 #endif
 #ifdef CONFIG_HIGHMEM
          32,
 #endif
          32,
 };
 
 EXPORT_SYMBOL(totalram_pages);
 
 static char * const zone_names[MAX_NR_ZONES] = {
 #ifdef CONFIG_ZONE_DMA
          "DMA",
 #endif
 #ifdef CONFIG_ZONE_DMA32
          "DMA32",
 #endif
          "Normal",
 #ifdef CONFIG_HIGHMEM
          "HighMem",
 #endif
          "Movable",
 };
 
 int min_free_kbytes = 1024;
 
 unsigned long __meminitdata nr_kernel_pages;
 unsigned long __meminitdata nr_all_pages;
 static unsigned long __meminitdata dma_reserve;
 
 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
   /*
    * MAX_ACTIVE_REGIONS determines the maximum number of distinct
    * ranges of memory (RAM) that may be registered with add_active_range().
    * Ranges passed to add_active_range() will be merged if possible
    * so the number of times add_active_range() can be called is
    * related to the number of nodes and the number of holes
    */
   #ifdef CONFIG_MAX_ACTIVE_REGIONS
     /* Allow an architecture to set MAX_ACTIVE_REGIONS to save memory */
     #define MAX_ACTIVE_REGIONS CONFIG_MAX_ACTIVE_REGIONS
   #else
     #if MAX_NUMNODES >= 32
       /* If there can be many nodes, allow up to 50 holes per node */
       #define MAX_ACTIVE_REGIONS (MAX_NUMNODES*50)
     #else
       /* By default, allow up to 256 distinct regions */
       #define MAX_ACTIVE_REGIONS 256
     #endif
   #endif
 
   static struct node_active_region __meminitdata early_node_map[MAX_ACTIVE_REGIONS];
   static int __meminitdata nr_nodemap_entries;
   static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
   static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
   static unsigned long __initdata required_kernelcore;
   static unsigned long __initdata required_movablecore;
   static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
 
   /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
   int movable_zone;
   EXPORT_SYMBOL(movable_zone);
 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
 
 #if MAX_NUMNODES > 1
 int nr_node_ids __read_mostly = MAX_NUMNODES;
 int nr_online_nodes __read_mostly = 1;
 EXPORT_SYMBOL(nr_node_ids);
 EXPORT_SYMBOL(nr_online_nodes);
 #endif
 
 int page_group_by_mobility_disabled __read_mostly;
 
 static void set_pageblock_migratetype(struct page *page, int migratetype)
 {
 
         if (unlikely(page_group_by_mobility_disabled))
                 migratetype = MIGRATE_UNMOVABLE;
 
         set_pageblock_flags_group(page, (unsigned long)migratetype,
                                         PB_migrate, PB_migrate_end);
 }
 
 bool oom_killer_disabled __read_mostly;
 
 #ifdef CONFIG_DEBUG_VM
 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
 {
         int ret = 0;
         unsigned seq;
         unsigned long pfn = page_to_pfn(page);
 
         do {
                 seq = zone_span_seqbegin(zone);
                 if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
                         ret = 1;
                 else if (pfn < zone->zone_start_pfn)
                         ret = 1;
         } while (zone_span_seqretry(zone, seq));
 
         return ret;
 }
 
 static int page_is_consistent(struct zone *zone, struct page *page)
 {
         if (!pfn_valid_within(page_to_pfn(page)))
                 return 0;
         if (zone != page_zone(page))
                 return 0;
 
         return 1;
 }
 /*
  * Temporary debugging check for pages not lying within a given zone.
  */
 static int bad_range(struct zone *zone, struct page *page)
 {
         if (page_outside_zone_boundaries(zone, page))
                 return 1;
         if (!page_is_consistent(zone, page))
                 return 1;
 
         return 0;
 }
 #else
 static inline int bad_range(struct zone *zone, struct page *page)
 {
         return 0;
 }
 #endif
 
 static void bad_page(struct page *page)
 {
         static unsigned long resume;
         static unsigned long nr_shown;
         static unsigned long nr_unshown;
 
         /*
          * Allow a burst of 60 reports, then keep quiet for that minute;
          * or allow a steady drip of one report per second.
          */
         if (nr_shown == 60) {
                 if (time_before(jiffies, resume)) {
                         nr_unshown++;
                         goto out;
                 }
                 if (nr_unshown) {
                         printk(KERN_ALERT
                               "BUG: Bad page state: %lu messages suppressed\n",
                                 nr_unshown);
                         nr_unshown = 0;
                 }
                 nr_shown = 0;
         }
         if (nr_shown++ == 0)
                 resume = jiffies + 60 * HZ;
 
         printk(KERN_ALERT "BUG: Bad page state in process %s  pfn:%05lx\n",
                 current->comm, page_to_pfn(page));
         printk(KERN_ALERT
                 "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
                 page, (void *)page->flags, page_count(page),
                 page_mapcount(page), page->mapping, page->index);
 
         dump_stack();
 out:
         /* Leave bad fields for debug, except PageBuddy could make trouble */
         __ClearPageBuddy(page);
         add_taint(TAINT_BAD_PAGE);
 }
 
 /*
  * Higher-order pages are called "compound pages".  They are structured thusly:
  *
  * The first PAGE_SIZE page is called the "head page".
  *
  * The remaining PAGE_SIZE pages are called "tail pages".
  *
  * All pages have PG_compound set.  All pages have their ->private pointing at
  * the head page (even the head page has this).
  *
  * The first tail page's ->lru.next holds the address of the compound page's
  * put_page() function.  Its ->lru.prev holds the order of allocation.
  * This usage means that zero-order pages may not be compound.
  */
 
 static void free_compound_page(struct page *page)
 {
         __free_pages_ok(page, compound_order(page));
 }
 
 void prep_compound_page(struct page *page, unsigned long order)
 {
         int i;
         int nr_pages = 1 << order;
 
         set_compound_page_dtor(page, free_compound_page);
         set_compound_order(page, order);
         __SetPageHead(page);
         for (i = 1; i < nr_pages; i++) {
                 struct page *p = page + i;
 
                 __SetPageTail(p);
                 p->first_page = page;
         }
 }
 
 static int destroy_compound_page(struct page *page, unsigned long order)
 {
         int i;
         int nr_pages = 1 << order;
         int bad = 0;
 
         if (unlikely(compound_order(page) != order) ||
             unlikely(!PageHead(page))) {
                 bad_page(page);
                 bad++;
         }
 
         __ClearPageHead(page);
 
         for (i = 1; i < nr_pages; i++) {
                 struct page *p = page + i;
 
                 if (unlikely(!PageTail(p) || (p->first_page != page))) {
                         bad_page(page);
                         bad++;
                 }
                 __ClearPageTail(p);
         }
 
         return bad;
 }
 
 static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
 {
         int i;
 
         /*
          * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
          * and __GFP_HIGHMEM from hard or soft interrupt context.
          */
         VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
         for (i = 0; i < (1 << order); i++)
                 clear_highpage(page + i);
 }
 
 static inline void set_page_order(struct page *page, int order)
 {
         set_page_private(page, order);
         __SetPageBuddy(page);
 }
 
 static inline void rmv_page_order(struct page *page)
 {
         __ClearPageBuddy(page);
         set_page_private(page, 0);
 }
 
 /*
  * Locate the struct page for both the matching buddy in our
  * pair (buddy1) and the combined O(n+1) page they form (page).
  *
  * 1) Any buddy B1 will have an order O twin B2 which satisfies
  * the following equation:
  *     B2 = B1 ^ (1 << O)
  * For example, if the starting buddy (buddy2) is #8 its order
  * 1 buddy is #10:
  *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
  *
  * 2) Any buddy B will have an order O+1 parent P which
  * satisfies the following equation:
  *     P = B & ~(1 << O)
  *
  * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
  */
 static inline struct page *
 __page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
 {
         unsigned long buddy_idx = page_idx ^ (1 << order);
 
         return page + (buddy_idx - page_idx);
 }
 
 static inline unsigned long
 __find_combined_index(unsigned long page_idx, unsigned int order)
 {
         return (page_idx & ~(1 << order));
 }
 
 /*
  * This function checks whether a page is free && is the buddy
  * we can do coalesce a page and its buddy if
  * (a) the buddy is not in a hole &&
  * (b) the buddy is in the buddy system &&
  * (c) a page and its buddy have the same order &&
  * (d) a page and its buddy are in the same zone.
  *
  * For recording whether a page is in the buddy system, we use PG_buddy.
  * Setting, clearing, and testing PG_buddy is serialized by zone->lock.
  *
  * For recording page's order, we use page_private(page).
  */
 static inline int page_is_buddy(struct page *page, struct page *buddy,
                                                                 int order)
 {
         if (!pfn_valid_within(page_to_pfn(buddy)))
                 return 0;
 
         if (page_zone_id(page) != page_zone_id(buddy))
                 return 0;
 
         if (PageBuddy(buddy) && page_order(buddy) == order) {
                 VM_BUG_ON(page_count(buddy) != 0);
                 return 1;
         }
         return 0;
 }
 
 /*
  * Freeing function for a buddy system allocator.
  *
  * The concept of a buddy system is to maintain direct-mapped table
  * (containing bit values) for memory blocks of various "orders".
  * The bottom level table contains the map for the smallest allocatable
  * units of memory (here, pages), and each level above it describes
  * pairs of units from the levels below, hence, "buddies".
  * At a high level, all that happens here is marking the table entry
  * at the bottom level available, and propagating the changes upward
  * as necessary, plus some accounting needed to play nicely with other
  * parts of the VM system.
  * At each level, we keep a list of pages, which are heads of continuous
  * free pages of length of (1 << order) and marked with PG_buddy. Page's
  * order is recorded in page_private(page) field.
  * So when we are allocating or freeing one, we can derive the state of the
  * other.  That is, if we allocate a small block, and both were   
  * free, the remainder of the region must be split into blocks.   
  * If a block is freed, and its buddy is also free, then this
  * triggers coalescing into a block of larger size.            
  *
  * -- wli
  */
 
 static inline void __free_one_page(struct page *page,
                 struct zone *zone, unsigned int order,
                 int migratetype)
 {
         unsigned long page_idx;
 
         if (unlikely(PageCompound(page)))
                 if (unlikely(destroy_compound_page(page, order)))
                         return;
 
         VM_BUG_ON(migratetype == -1);
 
         page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
 
         VM_BUG_ON(page_idx & ((1 << order) - 1));
         VM_BUG_ON(bad_range(zone, page));
 
         while (order < MAX_ORDER-1) {
                 unsigned long combined_idx;
                 struct page *buddy;
 
                 buddy = __page_find_buddy(page, page_idx, order);
                 if (!page_is_buddy(page, buddy, order))
                         break;
 
                 /* Our buddy is free, merge with it and move up one order. */
                 list_del(&buddy->lru);
                 zone->free_area[order].nr_free--;
                 rmv_page_order(buddy);
                 combined_idx = __find_combined_index(page_idx, order);
                 page = page + (combined_idx - page_idx);
                 page_idx = combined_idx;
                 order++;
         }
         set_page_order(page, order);
         list_add(&page->lru,
                 &zone->free_area[order].free_list[migratetype]);
         zone->free_area[order].nr_free++;
 }
 
 #ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
 /*
  * free_page_mlock() -- clean up attempts to free and mlocked() page.
  * Page should not be on lru, so no need to fix that up.
  * free_pages_check() will verify...
  */
 static inline void free_page_mlock(struct page *page)
 {
         __dec_zone_page_state(page, NR_MLOCK);
         __count_vm_event(UNEVICTABLE_MLOCKFREED);
 }
 #else
 static void free_page_mlock(struct page *page) { }
 #endif
 
 static inline int free_pages_check(struct page *page)
 {
         if (unlikely(page_mapcount(page) |
                 (page->mapping != NULL)  |
                 (atomic_read(&page->_count) != 0) |
                 (page->flags & PAGE_FLAGS_CHECK_AT_FREE))) {
                 bad_page(page);
                 return 1;
         }
         if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
                 page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
         return 0;
 }
 
 /*
  * Frees a list of pages. 
  * Assumes all pages on list are in same zone, and of same order.
  * count is the number of pages to free.
  *
  * If the zone was previously in an "all pages pinned" state then look to
  * see if this freeing clears that state.
  *
  * And clear the zone's pages_scanned counter, to hold off the "all pages are
  * pinned" detection logic.
  */
 static void free_pages_bulk(struct zone *zone, int count,
                                         struct list_head *list, int order)
 {
         spin_lock(&zone->lock);
         zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
         zone->pages_scanned = 0;
 
         __mod_zone_page_state(zone, NR_FREE_PAGES, count << order);
         while (count--) {
                 struct page *page;
 
                 VM_BUG_ON(list_empty(list));
                 page = list_entry(list->prev, struct page, lru);
                 /* have to delete it as __free_one_page list manipulates */
                 list_del(&page->lru);
                 __free_one_page(page, zone, order, page_private(page));
         }
         spin_unlock(&zone->lock);
 }
 
 static void free_one_page(struct zone *zone, struct page *page, int order,
                                 int migratetype)
 {
         spin_lock(&zone->lock);
         zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
         zone->pages_scanned = 0;
 
         __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
         __free_one_page(page, zone, order, migratetype);
         spin_unlock(&zone->lock);
 }
 
 static void __free_pages_ok(struct page *page, unsigned int order)
 {
         unsigned long flags;
         int i;
         int bad = 0;
         int wasMlocked = TestClearPageMlocked(page);
 
         kmemcheck_free_shadow(page, order);
 
         for (i = 0 ; i < (1 << order) ; ++i)
                 bad += free_pages_check(page + i);
         if (bad)
                 return;
 
         if (!PageHighMem(page)) {
                 debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
                 debug_check_no_obj_freed(page_address(page),
                                            PAGE_SIZE << order);
         }
         arch_free_page(page, order);
         kernel_map_pages(page, 1 << order, 0);
 
         local_irq_save(flags);
         if (unlikely(wasMlocked))
                 free_page_mlock(page);
         __count_vm_events(PGFREE, 1 << order);
         free_one_page(page_zone(page), page, order,
                                         get_pageblock_migratetype(page));
         local_irq_restore(flags);
 }
 
 /*
  * permit the bootmem allocator to evade page validation on high-order frees
  */
 void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
 {
         if (order == 0) {
                 __ClearPageReserved(page);
                 set_page_count(page, 0);
                 set_page_refcounted(page);
                 __free_page(page);
         } else {
                 int loop;
 
                 prefetchw(page);
                 for (loop = 0; loop < BITS_PER_LONG; loop++) {
                         struct page *p = &page[loop];
 
                         if (loop + 1 < BITS_PER_LONG)
                                 prefetchw(p + 1);
                         __ClearPageReserved(p);
                         set_page_count(p, 0);
                 }
 
                 set_page_refcounted(page);
                 __free_pages(page, order);
         }
 }
 
 
 /*
  * The order of subdivision here is critical for the IO subsystem.
  * Please do not alter this order without good reasons and regression
  * testing. Specifically, as large blocks of memory are subdivided,
  * the order in which smaller blocks are delivered depends on the order
  * they're subdivided in this function. This is the primary factor
  * influencing the order in which pages are delivered to the IO
  * subsystem according to empirical testing, and this is also justified
  * by considering the behavior of a buddy system containing a single
  * large block of memory acted on by a series of small allocations.
  * This behavior is a critical factor in sglist merging's success.
  *
  * -- wli
  */
 static inline void expand(struct zone *zone, struct page *page,
         int low, int high, struct free_area *area,
         int migratetype)
 {
         unsigned long size = 1 << high;
 
         while (high > low) {
                 area--;
                 high--;
                 size >>= 1;
                 VM_BUG_ON(bad_range(zone, &page[size]));
                 list_add(&page[size].lru, &area->free_list[migratetype]);
                 area->nr_free++;
                 set_page_order(&page[size], high);
         }
 }
 
 /*
  * This page is about to be returned from the page allocator
  */
 static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
 {
         if (unlikely(page_mapcount(page) |
                 (page->mapping != NULL)  |
                 (atomic_read(&page->_count) != 0)  |
                 (page->flags & PAGE_FLAGS_CHECK_AT_PREP))) {
                 bad_page(page);
                 return 1;
         }
 
         set_page_private(page, 0);
         set_page_refcounted(page);
 
         arch_alloc_page(page, order);
         kernel_map_pages(page, 1 << order, 1);
 
         if (gfp_flags & __GFP_ZERO)
                 prep_zero_page(page, order, gfp_flags);
 
         if (order && (gfp_flags & __GFP_COMP))
                 prep_compound_page(page, order);
 
         return 0;
 }
 
 /*
  * Go through the free lists for the given migratetype and remove
  * the smallest available page from the freelists
  */
 static inline
 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
                                                 int migratetype)
 {
         unsigned int current_order;
         struct free_area * area;
         struct page *page;
 
         /* Find a page of the appropriate size in the preferred list */
         for (current_order = order; current_order < MAX_ORDER; ++current_order) {
                 area = &(zone->free_area[current_order]);
                 if (list_empty(&area->free_list[migratetype]))
                         continue;
 
                 page = list_entry(area->free_list[migratetype].next,
                                                         struct page, lru);
                 list_del(&page->lru);
                 rmv_page_order(page);
                 area->nr_free--;
                 expand(zone, page, order, current_order, area, migratetype);
                 return page;
         }
 
         return NULL;
 }
 
 
 /*
  * This array describes the order lists are fallen back to when
  * the free lists for the desirable migrate type are depleted
  */
 static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = {
         [MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_RESERVE },
         [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_RESERVE },
         [MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
         [MIGRATE_RESERVE]     = { MIGRATE_RESERVE,     MIGRATE_RESERVE,   MIGRATE_RESERVE }, /* Never used */
 };
 
 /*
  * Move the free pages in a range to the free lists of the requested type.
  * Note that start_page and end_pages are not aligned on a pageblock
  * boundary. If alignment is required, use move_freepages_block()
  */
 static int move_freepages(struct zone *zone,
                           struct page *start_page, struct page *end_page,
                           int migratetype)
 {
         struct page *page;
         unsigned long order;
         int pages_moved = 0;
 
 #ifndef CONFIG_HOLES_IN_ZONE
         /*
          * page_zone is not safe to call in this context when
          * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
          * anyway as we check zone boundaries in move_freepages_block().
          * Remove at a later date when no bug reports exist related to
          * grouping pages by mobility
          */
         BUG_ON(page_zone(start_page) != page_zone(end_page));
 #endif
 
         for (page = start_page; page <= end_page;) {
                 /* Make sure we are not inadvertently changing nodes */
                 VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
 
                 if (!pfn_valid_within(page_to_pfn(page))) {
                         page++;
                         continue;
                 }
 
                 if (!PageBuddy(page)) {
                         page++;
                         continue;
                 }
 
                 order = page_order(page);
                 list_del(&page->lru);
                 list_add(&page->lru,
                         &zone->free_area[order].free_list[migratetype]);
                 page += 1 << order;
                 pages_moved += 1 << order;
         }
 
         return pages_moved;
 }
 
 static int move_freepages_block(struct zone *zone, struct page *page,
                                 int migratetype)
 {
         unsigned long start_pfn, end_pfn;
         struct page *start_page, *end_page;
 
         start_pfn = page_to_pfn(page);
         start_pfn = start_pfn & ~(pageblock_nr_pages-1);
         start_page = pfn_to_page(start_pfn);
         end_page = start_page + pageblock_nr_pages - 1;
         end_pfn = start_pfn + pageblock_nr_pages - 1;
 
         /* Do not cross zone boundaries */
         if (start_pfn < zone->zone_start_pfn)
                 start_page = page;
         if (end_pfn >= zone->zone_start_pfn + zone->spanned_pages)
                 return 0;
 
         return move_freepages(zone, start_page, end_page, migratetype);
 }
 
 /* Remove an element from the buddy allocator from the fallback list */
 static inline struct page *
 __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
 {
         struct free_area * area;
         int current_order;
         struct page *page;
         int migratetype, i;
 
         /* Find the largest possible block of pages in the other list */
         for (current_order = MAX_ORDER-1; current_order >= order;
                                                 --current_order) {
                 for (i = 0; i < MIGRATE_TYPES - 1; i++) {
                         migratetype = fallbacks[start_migratetype][i];
 
                         /* MIGRATE_RESERVE handled later if necessary */
                         if (migratetype == MIGRATE_RESERVE)
                                 continue;
 
                         area = &(zone->free_area[current_order]);
                         if (list_empty(&area->free_list[migratetype]))
                                 continue;
 
                         page = list_entry(area->free_list[migratetype].next,
                                         struct page, lru);
                         area->nr_free--;
 
                         /*
                          * If breaking a large block of pages, move all free
                          * pages to the preferred allocation list. If falling
                          * back for a reclaimable kernel allocation, be more
                          * agressive about taking ownership of free pages
                          */
                         if (unlikely(current_order >= (pageblock_order >> 1)) ||
                                         start_migratetype == MIGRATE_RECLAIMABLE ||
                                         page_group_by_mobility_disabled) {
                                 unsigned long pages;
                                 pages = move_freepages_block(zone, page,
                                                                 start_migratetype);
 
                                 /* Claim the whole block if over half of it is free */
                                 if (pages >= (1 << (pageblock_order-1)) ||
                                                 page_group_by_mobility_disabled)
                                         set_pageblock_migratetype(page,
                                                                 start_migratetype);
 
                                 migratetype = start_migratetype;
                         }
 
                         /* Remove the page from the freelists */
                         list_del(&page->lru);
                         rmv_page_order(page);
 
                         if (current_order == pageblock_order)
                                 set_pageblock_migratetype(page,
                                                         start_migratetype);
 
                         expand(zone, page, order, current_order, area, migratetype);
                         return page;
                 }
         }
 
         return NULL;
 }
 
 /*
  * Do the hard work of removing an element from the buddy allocator.
  * Call me with the zone->lock already held.
  */
 static struct page *__rmqueue(struct zone *zone, unsigned int order,
                                                 int migratetype)
 {
         struct page *page;
 
 retry_reserve:
         page = __rmqueue_smallest(zone, order, migratetype);
 
         if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
                 page = __rmqueue_fallback(zone, order, migratetype);
 
                 /*
                  * Use MIGRATE_RESERVE rather than fail an allocation. goto
                  * is used because __rmqueue_smallest is an inline function
                  * and we want just one call site
                  */
                 if (!page) {
                         migratetype = MIGRATE_RESERVE;
                         goto retry_reserve;
                 }
         }
 
         return page;
 }
 
 /* 
  * Obtain a specified number of elements from the buddy allocator, all under
  * a single hold of the lock, for efficiency.  Add them to the supplied list.
  * Returns the number of new pages which were placed at *list.
  */
 static int rmqueue_bulk(struct zone *zone, unsigned int order, 
                         unsigned long count, struct list_head *list,
                         int migratetype, int cold)
 {
         int i;
         
         spin_lock(&zone->lock);
         for (i = 0; i < count; ++i) {
                 struct page *page = __rmqueue(zone, order, migratetype);
                 if (unlikely(page == NULL))
                         break;
 
                 /*
                  * Split buddy pages returned by expand() are received here
                  * in physical page order. The page is added to the callers and
                  * list and the list head then moves forward. From the callers
                  * perspective, the linked list is ordered by page number in
                  * some conditions. This is useful for IO devices that can
                  * merge IO requests if the physical pages are ordered
                  * properly.
                  */
                 if (likely(cold == 0))
                         list_add(&page->lru, list);
                 else
                         list_add_tail(&page->lru, list);
                 set_page_private(page, migratetype);
                 list = &page->lru;
         }
         __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
         spin_unlock(&zone->lock);
         return i;
 }
 
 #ifdef CONFIG_NUMA
 /*
  * Called from the vmstat counter updater to drain pagesets of this
  * currently executing processor on remote nodes after they have
  * expired.
  *
  * Note that this function must be called with the thread pinned to
  * a single processor.
  */
 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
 {
         unsigned long flags;
         int to_drain;
 
         local_irq_save(flags);
         if (pcp->count >= pcp->batch)
                 to_drain = pcp->batch;
         else
                 to_drain = pcp->count;
         free_pages_bulk(zone, to_drain, &pcp->list, 0);
         pcp->count -= to_drain;
         local_irq_restore(flags);
 }
 #endif
 
 /*
  * Drain pages of the indicated processor.
  *
  * The processor must either be the current processor and the
  * thread pinned to the current processor or a processor that
  * is not online.
  */
 static void drain_pages(unsigned int cpu)
 {
         unsigned long flags;
         struct zone *zone;
 
         for_each_populated_zone(zone) {
                 struct per_cpu_pageset *pset;
                 struct per_cpu_pages *pcp;
 
                 pset = zone_pcp(zone, cpu);
 
                 pcp = &pset->pcp;
                 local_irq_save(flags);
                 free_pages_bulk(zone, pcp->count, &pcp->list, 0);
                 pcp->count = 0;
                 local_irq_restore(flags);
         }
 }
 
 /*
  * Spill all of this CPU's per-cpu pages back into the buddy allocator.
  */
 void drain_local_pages(void *arg)
 {
         drain_pages(smp_processor_id());
 }
 
 /*
  * Spill all the per-cpu pages from all CPUs back into the buddy allocator
  */
 void drain_all_pages(void)
 {
         on_each_cpu(drain_local_pages, NULL, 1);
 }
 
 #ifdef CONFIG_HIBERNATION
 
 void mark_free_pages(struct zone *zone)
 {
         unsigned long pfn, max_zone_pfn;
         unsigned long flags;
         int order, t;
         struct list_head *curr;
 
         if (!zone->spanned_pages)
                 return;
 
         spin_lock_irqsave(&zone->lock, flags);
 
         max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
         for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
                 if (pfn_valid(pfn)) {
                         struct page *page = pfn_to_page(pfn);
 
                         if (!swsusp_page_is_forbidden(page))
                                 swsusp_unset_page_free(page);
                 }
 
         for_each_migratetype_order(order, t) {
                 list_for_each(curr, &zone->free_area[order].free_list[t]) {
                         unsigned long i;
 
                         pfn = page_to_pfn(list_entry(curr, struct page, lru));
                         for (i = 0; i < (1UL << order); i++)
                                 swsusp_set_page_free(pfn_to_page(pfn + i));
                 }
         }
         spin_unlock_irqrestore(&zone->lock, flags);
 }
 #endif /* CONFIG_PM */
 
 /*
  * Free a 0-order page
  */
 static void free_hot_cold_page(struct page *page, int cold)
 {
         struct zone *zone = page_zone(page);
         struct per_cpu_pages *pcp;
         unsigned long flags;
         int wasMlocked = TestClearPageMlocked(page);
 
         kmemcheck_free_shadow(page, 0);
 
         if (PageAnon(page))
                 page->mapping = NULL;
         if (free_pages_check(page))
                 return;
 
         if (!PageHighMem(page)) {
                 debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
                 debug_check_no_obj_freed(page_address(page), PAGE_SIZE);
         }
         arch_free_page(page, 0);
         kernel_map_pages(page, 1, 0);
 
         pcp = &zone_pcp(zone, get_cpu())->pcp;
         set_page_private(page, get_pageblock_migratetype(page));
         local_irq_save(flags);
         if (unlikely(wasMlocked))
                 free_page_mlock(page);
         __count_vm_event(PGFREE);
 
         if (cold)
                 list_add_tail(&page->lru, &pcp->list);
         else
                 list_add(&page->lru, &pcp->list);
         pcp->count++;
         if (pcp->count >= pcp->high) {
                 free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
                 pcp->count -= pcp->batch;
         }
         local_irq_restore(flags);
         put_cpu();
 }
 
 void free_hot_page(struct page *page)
 {
         free_hot_cold_page(page, 0);
 }
         
 void free_cold_page(struct page *page)
 {
         free_hot_cold_page(page, 1);
 }
 
 /*
  * split_page takes a non-compound higher-order page, and splits it into
  * n (1<<order) sub-pages: page[0..n]
  * Each sub-page must be freed individually.
  *
  * Note: this is probably too low level an operation for use in drivers.
  * Please consult with lkml before using this in your driver.
  */
 void split_page(struct page *page, unsigned int order)
 {
         int i;
 
         VM_BUG_ON(PageCompound(page));
         VM_BUG_ON(!page_count(page));
 
 #ifdef CONFIG_KMEMCHECK
         /*
          * Split shadow pages too, because free(page[0]) would
          * otherwise free the whole shadow.
          */
         if (kmemcheck_page_is_tracked(page))
                 split_page(virt_to_page(page[0].shadow), order);
 #endif
 
         for (i = 1; i < (1 << order); i++)
                 set_page_refcounted(page + i);
 }
 
 /*
  * Really, prep_compound_page() should be called from __rmqueue_bulk().  But
  * we cheat by calling it from here, in the order > 0 path.  Saves a branch
  * or two.
  */
 static inline
 struct page *buffered_rmqueue(struct zone *preferred_zone,
                         struct zone *zone, int order, gfp_t gfp_flags,
                         int migratetype)
 {
         unsigned long flags;
         struct page *page;
         int cold = !!(gfp_flags & __GFP_COLD);
         int cpu;
 
 again:
         cpu  = get_cpu();
         if (likely(order == 0)) {
                 struct per_cpu_pages *pcp;
 
                 pcp = &zone_pcp(zone, cpu)->pcp;
                 local_irq_save(flags);
                 if (!pcp->count) {
                         pcp->count = rmqueue_bulk(zone, 0,
                                         pcp->batch, &pcp->list,
                                         migratetype, cold);
                         if (unlikely(!pcp->count))
                                 goto failed;
                 }
 
                 /* Find a page of the appropriate migrate type */
                 if (cold) {
                         list_for_each_entry_reverse(page, &pcp->list, lru)
                                 if (page_private(page) == migratetype)
                                         break;
                 } else {
                         list_for_each_entry(page, &pcp->list, lru)
                                 if (page_private(page) == migratetype)
                                         break;
                 }
 
                 /* Allocate more to the pcp list if necessary */
                 if (unlikely(&page->lru == &pcp->list)) {
                         pcp->count += rmqueue_bulk(zone, 0,
                                         pcp->batch, &pcp->list,
                                         migratetype, cold);
                         page = list_entry(pcp->list.next, struct page, lru);
                 }
 
                 list_del(&page->lru);
                 pcp->count--;
         } else {
                 if (unlikely(gfp_flags & __GFP_NOFAIL)) {
                         /*
                          * __GFP_NOFAIL is not to be used in new code.
                          *
                          * All __GFP_NOFAIL callers should be fixed so that they
                          * properly detect and handle allocation failures.
                          *
                          * We most definitely don't want callers attempting to
                          * allocate greater than order-1 page units with
                          * __GFP_NOFAIL.
                          */
                         WARN_ON_ONCE(order > 1);
                 }
                 spin_lock_irqsave(&zone->lock, flags);
                 page = __rmqueue(zone, order, migratetype);
                 spin_unlock(&zone->lock);
                 if (!page)
                         goto failed;
                 __mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
         }
 
         __count_zone_vm_events(PGALLOC, zone, 1 << order);
         zone_statistics(preferred_zone, zone);
         local_irq_restore(flags);
         put_cpu();
 
         VM_BUG_ON(bad_range(zone, page));
         if (prep_new_page(page, order, gfp_flags))
                 goto again;
         return page;
 
 failed:
         local_irq_restore(flags);
         put_cpu();
         return NULL;
 }
 
 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
 #define ALLOC_WMARK_MIN         WMARK_MIN
 #define ALLOC_WMARK_LOW         WMARK_LOW
 #define ALLOC_WMARK_HIGH        WMARK_HIGH
 #define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
 
 /* Mask to get the watermark bits */
 #define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
 
 #define ALLOC_HARDER            0x10 /* try to alloc harder */
 #define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
 #define ALLOC_CPUSET            0x40 /* check for correct cpuset */
 
 #ifdef CONFIG_FAIL_PAGE_ALLOC
 
 static struct fail_page_alloc_attr {
         struct fault_attr attr;
 
         u32 ignore_gfp_highmem;
         u32 ignore_gfp_wait;
         u32 min_order;
 
 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
 
         struct dentry *ignore_gfp_highmem_file;
         struct dentry *ignore_gfp_wait_file;
         struct dentry *min_order_file;
 
 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
 
 } fail_page_alloc = {
         .attr = FAULT_ATTR_INITIALIZER,
         .ignore_gfp_wait = 1,
         .ignore_gfp_highmem = 1,
         .min_order = 1,
 };
 
 static int __init setup_fail_page_alloc(char *str)
 {
         return setup_fault_attr(&fail_page_alloc.attr, str);
 }
 __setup("fail_page_alloc=", setup_fail_page_alloc);
 
 static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
 {
         if (order < fail_page_alloc.min_order)
                 return 0;
         if (gfp_mask & __GFP_NOFAIL)
                 return 0;
         if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
                 return 0;
         if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
                 return 0;
 
         return should_fail(&fail_page_alloc.attr, 1 << order);
 }
 
 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
 
 static int __init fail_page_alloc_debugfs(void)
 {
         mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
         struct dentry *dir;
         int err;
 
         err = init_fault_attr_dentries(&fail_page_alloc.attr,
                                        "fail_page_alloc");
         if (err)
                 return err;
         dir = fail_page_alloc.attr.dentries.dir;
 
         fail_page_alloc.ignore_gfp_wait_file =
                 debugfs_create_bool("ignore-gfp-wait", mode, dir,
                                       &fail_page_alloc.ignore_gfp_wait);
 
         fail_page_alloc.ignore_gfp_highmem_file =
                 debugfs_create_bool("ignore-gfp-highmem", mode, dir,
                                       &fail_page_alloc.ignore_gfp_highmem);
         fail_page_alloc.min_order_file =
                 debugfs_create_u32("min-order", mode, dir,
                                    &fail_page_alloc.min_order);
 
         if (!fail_page_alloc.ignore_gfp_wait_file ||
             !fail_page_alloc.ignore_gfp_highmem_file ||
             !fail_page_alloc.min_order_file) {
                 err = -ENOMEM;
                 debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
                 debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
                 debugfs_remove(fail_page_alloc.min_order_file);
                 cleanup_fault_attr_dentries(&fail_page_alloc.attr);
         }
 
         return err;
 }
 
 late_initcall(fail_page_alloc_debugfs);
 
 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
 
 #else /* CONFIG_FAIL_PAGE_ALLOC */
 
 static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
 {
         return 0;
 }
 
 #endif /* CONFIG_FAIL_PAGE_ALLOC */
 
 /*
  * Return 1 if free pages are above 'mark'. This takes into account the order
  * of the allocation.
  */
 int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
                       int classzone_idx, int alloc_flags)
 {
         /* free_pages my go negative - that's OK */
         long min = mark;
         long free_pages = zone_page_state(z, NR_FREE_PAGES) - (1 << order) + 1;
         int o;
 
         if (alloc_flags & ALLOC_HIGH)
                 min -= min / 2;
         if (alloc_flags & ALLOC_HARDER)
                 min -= min / 4;
 
         if (free_pages <= min + z->lowmem_reserve[classzone_idx])
                 return 0;
         for (o = 0; o < order; o++) {
                 /* At the next order, this order's pages become unavailable */
                 free_pages -= z->free_area[o].nr_free << o;
 
                 /* Require fewer higher order pages to be free */
                 min >>= 1;
 
                 if (free_pages <= min)
                         return 0;
         }
         return 1;
 }
 
 #ifdef CONFIG_NUMA
 /*
  * zlc_setup - Setup for "zonelist cache".  Uses cached zone data to
  * skip over zones that are not allowed by the cpuset, or that have
  * been recently (in last second) found to be nearly full.  See further
  * comments in mmzone.h.  Reduces cache footprint of zonelist scans
  * that have to skip over a lot of full or unallowed zones.
  *
  * If the zonelist cache is present in the passed in zonelist, then
  * returns a pointer to the allowed node mask (either the current
  * tasks mems_allowed, or node_states[N_HIGH_MEMORY].)
  *
  * If the zonelist cache is not available for this zonelist, does
  * nothing and returns NULL.
  *
  * If the fullzones BITMAP in the zonelist cache is stale (more than
  * a second since last zap'd) then we zap it out (clear its bits.)
  *
  * We hold off even calling zlc_setup, until after we've checked the
  * first zone in the zonelist, on the theory that most allocations will
  * be satisfied from that first zone, so best to examine that zone as
  * quickly as we can.
  */
 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
 {
         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
         nodemask_t *allowednodes;       /* zonelist_cache approximation */
 
         zlc = zonelist->zlcache_ptr;
         if (!zlc)
                 return NULL;
 
         if (time_after(jiffies, zlc->last_full_zap + HZ)) {
                 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
                 zlc->last_full_zap = jiffies;
         }
 
         allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
                                         &cpuset_current_mems_allowed :
                                         &node_states[N_HIGH_MEMORY];
         return allowednodes;
 }
 
 /*
  * Given 'z' scanning a zonelist, run a couple of quick checks to see
  * if it is worth looking at further for free memory:
  *  1) Check that the zone isn't thought to be full (doesn't have its
  *     bit set in the zonelist_cache fullzones BITMAP).
  *  2) Check that the zones node (obtained from the zonelist_cache
  *     z_to_n[] mapping) is allowed in the passed in allowednodes mask.
  * Return true (non-zero) if zone is worth looking at further, or
  * else return false (zero) if it is not.
  *
  * This check -ignores- the distinction between various watermarks,
  * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ...  If a zone is
  * found to be full for any variation of these watermarks, it will
  * be considered full for up to one second by all requests, unless
  * we are so low on memory on all allowed nodes that we are forced
  * into the second scan of the zonelist.
  *
  * In the second scan we ignore this zonelist cache and exactly
  * apply the watermarks to all zones, even it is slower to do so.
  * We are low on memory in the second scan, and should leave no stone
  * unturned looking for a free page.
  */
 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
                                                 nodemask_t *allowednodes)
 {
         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
         int i;                          /* index of *z in zonelist zones */
         int n;                          /* node that zone *z is on */
 
         zlc = zonelist->zlcache_ptr;
         if (!zlc)
                 return 1;
 
         i = z - zonelist->_zonerefs;
         n = zlc->z_to_n[i];
 
         /* This zone is worth trying if it is allowed but not full */
         return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
 }
 
 /*
  * Given 'z' scanning a zonelist, set the corresponding bit in
  * zlc->fullzones, so that subsequent attempts to allocate a page
  * from that zone don't waste time re-examining it.
  */
 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
 {
         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
         int i;                          /* index of *z in zonelist zones */
 
         zlc = zonelist->zlcache_ptr;
         if (!zlc)
                 return;
 
         i = z - zonelist->_zonerefs;
 
         set_bit(i, zlc->fullzones);
 }
 
 #else   /* CONFIG_NUMA */
 
 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
 {
         return NULL;
 }
 
 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
                                 nodemask_t *allowednodes)
 {
         return 1;
 }
 
 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
 {
 }
 #endif  /* CONFIG_NUMA */
 
 /*
  * get_page_from_freelist goes through the zonelist trying to allocate
  * a page.
  */
 static struct page *
 get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
                 struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
                 struct zone *preferred_zone, int migratetype)
 {
         struct zoneref *z;
         struct page *page = NULL;
         int classzone_idx;
         struct zone *zone;
         nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
         int zlc_active = 0;             /* set if using zonelist_cache */
         int did_zlc_setup = 0;          /* just call zlc_setup() one time */
 
         classzone_idx = zone_idx(preferred_zone);
 zonelist_scan:
         /*
          * Scan zonelist, looking for a zone with enough free.
          * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
          */
         for_each_zone_zonelist_nodemask(zone, z, zonelist,
                                                 high_zoneidx, nodemask) {
                 if (NUMA_BUILD && zlc_active &&
                         !zlc_zone_worth_trying(zonelist, z, allowednodes))
                                 continue;
                 if ((alloc_flags & ALLOC_CPUSET) &&
                         !cpuset_zone_allowed_softwall(zone, gfp_mask))
                                 goto try_next_zone;
 
                 BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
                 if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
                         unsigned long mark;
                         int ret;
 
                         mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
                         if (zone_watermark_ok(zone, order, mark,
                                     classzone_idx, alloc_flags))
                                 goto try_this_zone;
 
                         if (zone_reclaim_mode == 0)
                                 goto this_zone_full;
 
                         ret = zone_reclaim(zone, gfp_mask, order);
                         switch (ret) {
                         case ZONE_RECLAIM_NOSCAN:
                                 /* did not scan */
                                 goto try_next_zone;
                         case ZONE_RECLAIM_FULL:
                                 /* scanned but unreclaimable */
                                 goto this_zone_full;
                         default:
                                 /* did we reclaim enough */
                                 if (!zone_watermark_ok(zone, order, mark,
                                                 classzone_idx, alloc_flags))
                                         goto this_zone_full;
                         }
                 }
 
 try_this_zone:
                 page = buffered_rmqueue(preferred_zone, zone, order,
                                                 gfp_mask, migratetype);
                 if (page)
                         break;
 this_zone_full:
                 if (NUMA_BUILD)
                         zlc_mark_zone_full(zonelist, z);
 try_next_zone:
                 if (NUMA_BUILD && !did_zlc_setup && nr_online_nodes > 1) {
                         /*
                          * we do zlc_setup after the first zone is tried but only
                          * if there are multiple nodes make it worthwhile
                          */
                         allowednodes = zlc_setup(zonelist, alloc_flags);
                         zlc_active = 1;
                         did_zlc_setup = 1;
                 }
         }
 
         if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
                 /* Disable zlc cache for second zonelist scan */
                 zlc_active = 0;
                 goto zonelist_scan;
         }
         return page;
 }
 
 static inline int
 should_alloc_retry(gfp_t gfp_mask, unsigned int order,
                                 unsigned long pages_reclaimed)
 {
         /* Do not loop if specifically requested */
         if (gfp_mask & __GFP_NORETRY)
                 return 0;
 
         /*
          * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
          * means __GFP_NOFAIL, but that may not be true in other
          * implementations.
          */
         if (order <= PAGE_ALLOC_COSTLY_ORDER)
                 return 1;
 
         /*
          * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
          * specified, then we retry until we no longer reclaim any pages
          * (above), or we've reclaimed an order of pages at least as
          * large as the allocation's order. In both cases, if the
          * allocation still fails, we stop retrying.
          */
         if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
                 return 1;
 
         /*
          * Don't let big-order allocations loop unless the caller
          * explicitly requests that.
          */
         if (gfp_mask & __GFP_NOFAIL)
                 return 1;
 
         return 0;
 }
 
 static inline struct page *
 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
         struct zonelist *zonelist, enum zone_type high_zoneidx,
         nodemask_t *nodemask, struct zone *preferred_zone,
         int migratetype)
 {
         struct page *page;
 
         /* Acquire the OOM killer lock for the zones in zonelist */
         if (!try_set_zone_oom(zonelist, gfp_mask)) {
                 schedule_timeout_uninterruptible(1);
                 return NULL;
         }
 
         /*
          * Go through the zonelist yet one more time, keep very high watermark
          * here, this is only to catch a parallel oom killing, we must fail if
          * we're still under heavy pressure.
          */
         page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
                 order, zonelist, high_zoneidx,
                 ALLOC_WMARK_HIGH|ALLOC_CPUSET,
                 preferred_zone, migratetype);
         if (page)
                 goto out;
 
         /* The OOM killer will not help higher order allocs */
         if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_NOFAIL))
                 goto out;
 
         /* Exhausted what can be done so it's blamo time */
         out_of_memory(zonelist, gfp_mask, order);
 
 out:
         clear_zonelist_oom(zonelist, gfp_mask);
         return page;
 }
 
 /* The really slow allocator path where we enter direct reclaim */
 static inline struct page *
 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
         struct zonelist *zonelist, enum zone_type high_zoneidx,
         nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
         int migratetype, unsigned long *did_some_progress)
 {
         struct page *page = NULL;
         struct reclaim_state reclaim_state;
         struct task_struct *p = current;
 
         cond_resched();
 
         /* We now go into synchronous reclaim */
         cpuset_memory_pressure_bump();
 
         /*
          * The task's cpuset might have expanded its set of allowable nodes
          */
         p->flags |= PF_MEMALLOC;
         lockdep_set_current_reclaim_state(gfp_mask);
         reclaim_state.reclaimed_slab = 0;
         p->reclaim_state = &reclaim_state;
 
         *did_some_progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
 
         p->reclaim_state = NULL;
         lockdep_clear_current_reclaim_state();
         p->flags &= ~PF_MEMALLOC;
 
         cond_resched();
 
         if (order != 0)
                 drain_all_pages();
 
         if (likely(*did_some_progress))
                 page = get_page_from_freelist(gfp_mask, nodemask, order,
                                         zonelist, high_zoneidx,
                                         alloc_flags, preferred_zone,
                                         migratetype);
         return page;
 }
 
 /*
  * This is called in the allocator slow-path if the allocation request is of
  * sufficient urgency to ignore watermarks and take other desperate measures
  */
 static inline struct page *
 __alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
         struct zonelist *zonelist, enum zone_type high_zoneidx,
         nodemask_t *nodemask, struct zone *preferred_zone,
         int migratetype)
 {
         struct page *page;
 
         do {
                 page = get_page_from_freelist(gfp_mask, nodemask, order,
                         zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
                         preferred_zone, migratetype);
 
                 if (!page && gfp_mask & __GFP_NOFAIL)
                         congestion_wait(BLK_RW_ASYNC, HZ/50);
         } while (!page && (gfp_mask & __GFP_NOFAIL));
 
         return page;
 }
 
 static inline
 void wake_all_kswapd(unsigned int order, struct zonelist *zonelist,
                                                 enum zone_type high_zoneidx)
 {
         struct zoneref *z;
         struct zone *zone;
 
         for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
                 wakeup_kswapd(zone, order);
 }
 
 static inline int
 gfp_to_alloc_flags(gfp_t gfp_mask)
 {
         struct task_struct *p = current;
         int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
         const gfp_t wait = gfp_mask & __GFP_WAIT;
 
         /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
         BUILD_BUG_ON(__GFP_HIGH != ALLOC_HIGH);
 
         /*
          * The caller may dip into page reserves a bit more if the caller
          * cannot run direct reclaim, or if the caller has realtime scheduling
          * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
          * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
          */
         alloc_flags |= (gfp_mask & __GFP_HIGH);
 
         if (!wait) {
                 alloc_flags |= ALLOC_HARDER;
                 /*
                  * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
                  * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
                  */
                 alloc_flags &= ~ALLOC_CPUSET;
         } else if (unlikely(rt_task(p)) && !in_interrupt())
                 alloc_flags |= ALLOC_HARDER;
 
         if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
                 if (!in_interrupt() &&
                     ((p->flags & PF_MEMALLOC) ||
                      unlikely(test_thread_flag(TIF_MEMDIE))))
                         alloc_flags |= ALLOC_NO_WATERMARKS;
         }
 
         return alloc_flags;
 }
 
 static inline struct page *
 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
         struct zonelist *zonelist, enum zone_type high_zoneidx,
         nodemask_t *nodemask, struct zone *preferred_zone,
         int migratetype)
 {
         const gfp_t wait = gfp_mask & __GFP_WAIT;
         struct page *page = NULL;
         int alloc_flags;
         unsigned long pages_reclaimed = 0;
         unsigned long did_some_progress;
         struct task_struct *p = current;
 
         /*
          * In the slowpath, we sanity check order to avoid ever trying to
          * reclaim >= MAX_ORDER areas which will never succeed. Callers may
          * be using allocators in order of preference for an area that is
          * too large.
          */
         if (order >= MAX_ORDER) {
                 WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
                 return NULL;
         }
 
         /*
          * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
          * __GFP_NOWARN set) should not cause reclaim since the subsystem
          * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
          * using a larger set of nodes after it has established that the
          * allowed per node queues are empty and that nodes are
          * over allocated.
          */
         if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
                 goto nopage;
 
 restart:
         wake_all_kswapd(order, zonelist, high_zoneidx);
 
         /*
          * OK, we're below the kswapd watermark and have kicked background
          * reclaim. Now things get more complex, so set up alloc_flags according
          * to how we want to proceed.
          */
         alloc_flags = gfp_to_alloc_flags(gfp_mask);
 
         /* This is the last chance, in general, before the goto nopage. */
         page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
                         high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
                         preferred_zone, migratetype);
         if (page)
                 goto got_pg;
 
 rebalance:
         /* Allocate without watermarks if the context allows */
         if (alloc_flags & ALLOC_NO_WATERMARKS) {
                 page = __alloc_pages_high_priority(gfp_mask, order,
                                 zonelist, high_zoneidx, nodemask,
                                 preferred_zone, migratetype);
                 if (page)
                         goto got_pg;
         }
 
         /* Atomic allocations - we can't balance anything */
         if (!wait)
                 goto nopage;
 
         /* Avoid recursion of direct reclaim */
         if (p->flags & PF_MEMALLOC)
                 goto nopage;
 
         /* Avoid allocations with no watermarks from looping endlessly */
         if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
                 goto nopage;
 
         /* Try direct reclaim and then allocating */
         page = __alloc_pages_direct_reclaim(gfp_mask, order,
                                         zonelist, high_zoneidx,
                                         nodemask,
                                         alloc_flags, preferred_zone,
                                         migratetype, &did_some_progress);
         if (page)
                 goto got_pg;
 
         /*
          * If we failed to make any progress reclaiming, then we are
          * running out of options and have to consider going OOM
          */
         if (!did_some_progress) {
                 if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
                         if (oom_killer_disabled)
                                 goto nopage;
                         page = __alloc_pages_may_oom(gfp_mask, order,
                                         zonelist, high_zoneidx,
                                         nodemask, preferred_zone,
                                         migratetype);
                         if (page)
                                 goto got_pg;
 
                         /*
                          * The OOM killer does not trigger for high-order
                          * ~__GFP_NOFAIL allocations so if no progress is being
                          * made, there are no other options and retrying is
                          * unlikely to help.
                          */
                         if (order > PAGE_ALLOC_COSTLY_ORDER &&
                                                 !(gfp_mask & __GFP_NOFAIL))
                                 goto nopage;
 
                         goto restart;
                 }
         }
 
         /* Check if we should retry the allocation */
         pages_reclaimed += did_some_progress;
         if (should_alloc_retry(gfp_mask, order, pages_reclaimed)) {
                 /* Wait for some write requests to complete then retry */
                 congestion_wait(BLK_RW_ASYNC, HZ/50);
                 goto rebalance;
         }
 
 nopage:
         if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
                 printk(KERN_WARNING "%s: page allocation failure."
                         " order:%d, mode:0x%x\n",
                         p->comm, order, gfp_mask);
                 dump_stack();
                 show_mem();
         }
         return page;
 got_pg:
         if (kmemcheck_enabled)
                 kmemcheck_pagealloc_alloc(page, order, gfp_mask);
         return page;
 
 }
 
 /*
  * This is the 'heart' of the zoned buddy allocator.
  */
 struct page *
 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
                         struct zonelist *zonelist, nodemask_t *nodemask)
 {
         enum zone_type high_zoneidx = gfp_zone(gfp_mask);
         struct zone *preferred_zone;
         struct page *page;
         int migratetype = allocflags_to_migratetype(gfp_mask);
 
         gfp_mask &= gfp_allowed_mask;
 
         lockdep_trace_alloc(gfp_mask);
 
         might_sleep_if(gfp_mask & __GFP_WAIT);
 
         if (should_fail_alloc_page(gfp_mask, order))
                 return NULL;
 
         /*
          * Check the zones suitable for the gfp_mask contain at least one
          * valid zone. It's possible to have an empty zonelist as a result
          * of GFP_THISNODE and a memoryless node
          */
         if (unlikely(!zonelist->_zonerefs->zone))
                 return NULL;
 
         /* The preferred zone is used for statistics later */
         first_zones_zonelist(zonelist, high_zoneidx, nodemask, &preferred_zone);
         if (!preferred_zone)
                 return NULL;
 
         /* First allocation attempt */
         page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
                         zonelist, high_zoneidx, ALLOC_WMARK_LOW|ALLOC_CPUSET,
                         preferred_zone, migratetype);
         if (unlikely(!page))
                 page = __alloc_pages_slowpath(gfp_mask, order,
                                 zonelist, high_zoneidx, nodemask,
                                 preferred_zone, migratetype);
 
         return page;
 }
 EXPORT_SYMBOL(__alloc_pages_nodemask);
 
 /*
  * Common helper functions.
  */
 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
 {
         struct page * page;
         page = alloc_pages(gfp_mask, order);
         if (!page)
                 return 0;
         return (unsigned long) page_address(page);
 }
 
 EXPORT_SYMBOL(__get_free_pages);
 
 unsigned long get_zeroed_page(gfp_t gfp_mask)
 {
         struct page * page;
 
         /*
          * get_zeroed_page() returns a 32-bit address, which cannot represent
          * a highmem page
          */
         VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
 
         page = alloc_pages(gfp_mask | __GFP_ZERO, 0);
         if (page)
                 return (unsigned long) page_address(page);
         return 0;
 }
 
 EXPORT_SYMBOL(get_zeroed_page);
 
 void __pagevec_free(struct pagevec *pvec)
 {
         int i = pagevec_count(pvec);
 
         while (--i >= 0)
                 free_hot_cold_page(pvec->pages[i], pvec->cold);
 }
 
 void __free_pages(struct page *page, unsigned int order)
 {
         if (put_page_testzero(page)) {
                 if (order == 0)
                         free_hot_page(page);
                 else
                         __free_pages_ok(page, order);
         }
 }
 
 EXPORT_SYMBOL(__free_pages);
 
 void free_pages(unsigned long addr, unsigned int order)
 {
         if (addr != 0) {
                 VM_BUG_ON(!virt_addr_valid((void *)addr));
                 __free_pages(virt_to_page((void *)addr), order);
         }
 }
 
 EXPORT_SYMBOL(free_pages);
 
 /**
  * alloc_pages_exact - allocate an exact number physically-contiguous pages.
  * @size: the number of bytes to allocate
  * @gfp_mask: GFP flags for the allocation
  *
  * This function is similar to alloc_pages(), except that it allocates the
  * minimum number of pages to satisfy the request.  alloc_pages() can only
  * allocate memory in power-of-two pages.
  *
  * This function is also limited by MAX_ORDER.
  *
  * Memory allocated by this function must be released by free_pages_exact().
  */
 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
 {
         unsigned int order = get_order(size);
         unsigned long addr;
 
         addr = __get_free_pages(gfp_mask, order);
         if (addr) {
                 unsigned long alloc_end = addr + (PAGE_SIZE << order);
                 unsigned long used = addr + PAGE_ALIGN(size);
 
                 split_page(virt_to_page((void *)addr), order);
                 while (used < alloc_end) {
                         free_page(used);
                         used += PAGE_SIZE;
                 }
         }
 
         return (void *)addr;
 }
 EXPORT_SYMBOL(alloc_pages_exact);
 
 /**
  * free_pages_exact - release memory allocated via alloc_pages_exact()
  * @virt: the value returned by alloc_pages_exact.
  * @size: size of allocation, same value as passed to alloc_pages_exact().
  *
  * Release the memory allocated by a previous call to alloc_pages_exact.
  */
 void free_pages_exact(void *virt, size_t size)
 {
         unsigned long addr = (unsigned long)virt;
         unsigned long end = addr + PAGE_ALIGN(size);
 
         while (addr < end) {
                 free_page(addr);
                 addr += PAGE_SIZE;
         }
 }
 EXPORT_SYMBOL(free_pages_exact);
 
 static unsigned int nr_free_zone_pages(int offset)
 {
         struct zoneref *z;
         struct zone *zone;
 
         /* Just pick one node, since fallback list is circular */
         unsigned int sum = 0;
 
         struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
 
         for_each_zone_zonelist(zone, z, zonelist, offset) {
                 unsigned long size = zone->present_pages;
                 unsigned long high = high_wmark_pages(zone);
                 if (size > high)
                         sum += size - high;
         }
 
         return sum;
 }
 
 /*
  * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
  */
 unsigned int nr_free_buffer_pages(void)
 {
         return nr_free_zone_pages(gfp_zone(GFP_USER));
 }
 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
 
 /*
  * Amount of free RAM allocatable within all zones
  */
 unsigned int nr_free_pagecache_pages(void)
 {
         return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
 }
 
 static inline void show_node(struct zone *zone)
 {
         if (NUMA_BUILD)
                 printk("Node %d ", zone_to_nid(zone));
 }
 
 void si_meminfo(struct sysinfo *val)
 {
         val->totalram = totalram_pages;
         val->sharedram = 0;
         val->freeram = global_page_state(NR_FREE_PAGES);
         val->bufferram = nr_blockdev_pages();
         val->totalhigh = totalhigh_pages;
         val->freehigh = nr_free_highpages();
         val->mem_unit = PAGE_SIZE;
 }
 
 EXPORT_SYMBOL(si_meminfo);
 
 #ifdef CONFIG_NUMA
 void si_meminfo_node(struct sysinfo *val, int nid)
 {
         pg_data_t *pgdat = NODE_DATA(nid);
 
         val->totalram = pgdat->node_present_pages;
         val->freeram = node_page_state(nid, NR_FREE_PAGES);
 #ifdef CONFIG_HIGHMEM
         val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
         val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
                         NR_FREE_PAGES);
 #else
         val->totalhigh = 0;
         val->freehigh = 0;
 #endif
         val->mem_unit = PAGE_SIZE;
 }
 #endif
 
 #define K(x) ((x) << (PAGE_SHIFT-10))
 
 /*
  * Show free area list (used inside shift_scroll-lock stuff)
  * We also calculate the percentage fragmentation. We do this by counting the
  * memory on each free list with the exception of the first item on the list.
  */
 void show_free_areas(void)
 {
         int cpu;
         struct zone *zone;
 
         for_each_populated_zone(zone) {
                 show_node(zone);
                 printk("%s per-cpu:\n", zone->name);
 
                 for_each_online_cpu(cpu) {
                         struct per_cpu_pageset *pageset;
 
                         pageset = zone_pcp(zone, cpu);
 
                         printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
                                cpu, pageset->pcp.high,
                                pageset->pcp.batch, pageset->pcp.count);
                 }
         }
 
         printk("Active_anon:%lu active_file:%lu inactive_anon:%lu\n"
                 " inactive_file:%lu"
                 " unevictable:%lu"
                 " dirty:%lu writeback:%lu unstable:%lu\n"
                 " free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n",
                 global_page_state(NR_ACTIVE_ANON),
                 global_page_state(NR_ACTIVE_FILE),
                 global_page_state(NR_INACTIVE_ANON),
                 global_page_state(NR_INACTIVE_FILE),
                 global_page_state(NR_UNEVICTABLE),
                 global_page_state(NR_FILE_DIRTY),
                 global_page_state(NR_WRITEBACK),
                 global_page_state(NR_UNSTABLE_NFS),
                 global_page_state(NR_FREE_PAGES),
                 global_page_state(NR_SLAB_RECLAIMABLE) +
                         global_page_state(NR_SLAB_UNRECLAIMABLE),
                 global_page_state(NR_FILE_MAPPED),
                 global_page_state(NR_PAGETABLE),
                 global_page_state(NR_BOUNCE));
 
         for_each_populated_zone(zone) {
                 int i;
 
                 show_node(zone);
                 printk("%s"
                         " free:%lukB"
                         " min:%lukB"
                         " low:%lukB"
                         " high:%lukB"
                         " active_anon:%lukB"
                         " inactive_anon:%lukB"
                         " active_file:%lukB"
                         " inactive_file:%lukB"
                         " unevictable:%lukB"
                         " present:%lukB"
                         " pages_scanned:%lu"
                         " all_unreclaimable? %s"
                         "\n",
                         zone->name,
                         K(zone_page_state(zone, NR_FREE_PAGES)),
                         K(min_wmark_pages(zone)),
                         K(low_wmark_pages(zone)),
                         K(high_wmark_pages(zone)),
                         K(zone_page_state(zone, NR_ACTIVE_ANON)),
                         K(zone_page_state(zone, NR_INACTIVE_ANON)),
                         K(zone_page_state(zone, NR_ACTIVE_FILE)),
                         K(zone_page_state(zone, NR_INACTIVE_FILE)),
                         K(zone_page_state(zone, NR_UNEVICTABLE)),
                         K(zone->present_pages),
                         zone->pages_scanned,
                         (zone_is_all_unreclaimable(zone) ? "yes" : "no")
                         );
                 printk("lowmem_reserve[]:");
                 for (i = 0; i < MAX_NR_ZONES; i++)
                         printk(" %lu", zone->lowmem_reserve[i]);
                 printk("\n");
         }
 
         for_each_populated_zone(zone) {
                 unsigned long nr[MAX_ORDER], flags, order, total = 0;
 
                 show_node(zone);
                 printk("%s: ", zone->name);
 
                 spin_lock_irqsave(&zone->lock, flags);
                 for (order = 0; order < MAX_ORDER; order++) {
                         nr[order] = zone->free_area[order].nr_free;
                         total += nr[order] << order;
                 }
                 spin_unlock_irqrestore(&zone->lock, flags);
                 for (order = 0; order < MAX_ORDER; order++)
                         printk("%lu*%lukB ", nr[order], K(1UL) << order);
                 printk("= %lukB\n", K(total));
         }
 
         printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
 
         show_swap_cache_info();
 }
 
 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
 {
         zoneref->zone = zone;
         zoneref->zone_idx = zone_idx(zone);
 }
 
 /*
  * Builds allocation fallback zone lists.
  *
  * Add all populated zones of a node to the zonelist.
  */
 static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
                                 int nr_zones, enum zone_type zone_type)
 {
         struct zone *zone;
 
         BUG_ON(zone_type >= MAX_NR_ZONES);
         zone_type++;
 
         do {
                 zone_type--;
                 zone = pgdat->node_zones + zone_type;
                 if (populated_zone(zone)) {
                         zoneref_set_zone(zone,
                                 &zonelist->_zonerefs[nr_zones++]);
                         check_highest_zone(zone_type);
                 }
 
         } while (zone_type);
         return nr_zones;
 }
 
 
 /*
  *  zonelist_order:
  *  0 = automatic detection of better ordering.
  *  1 = order by ([node] distance, -zonetype)
  *  2 = order by (-zonetype, [node] distance)
  *
  *  If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
  *  the same zonelist. So only NUMA can configure this param.
  */
 #define ZONELIST_ORDER_DEFAULT  0
 #define ZONELIST_ORDER_NODE     1
 #define ZONELIST_ORDER_ZONE     2
 
 /* zonelist order in the kernel.
  * set_zonelist_order() will set this to NODE or ZONE.
  */
 static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
 static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
 
 
 #ifdef CONFIG_NUMA
 /* The value user specified ....changed by config */
 static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
 /* string for sysctl */
 #define NUMA_ZONELIST_ORDER_LEN 16
 char numa_zonelist_order[16] = "default";
 
 /*
  * interface for configure zonelist ordering.
  * command line option "numa_zonelist_order"
  *      = "[dD]efault   - default, automatic configuration.
  *      = "[nN]ode      - order by node locality, then by zone within node
  *      = "[zZ]one      - order by zone, then by locality within zone
  */
 
 static int __parse_numa_zonelist_order(char *s)
 {
         if (*s == 'd' || *s == 'D') {
                 user_zonelist_order = ZONELIST_ORDER_DEFAULT;
         } else if (*s == 'n' || *s == 'N') {
                 user_zonelist_order = ZONELIST_ORDER_NODE;
         } else if (*s == 'z' || *s == 'Z') {
                 user_zonelist_order = ZONELIST_ORDER_ZONE;
         } else {
                 printk(KERN_WARNING
                         "Ignoring invalid numa_zonelist_order value:  "
                         "%s\n", s);
                 return -EINVAL;
         }
         return 0;
 }
 
 static __init int setup_numa_zonelist_order(char *s)
 {
         if (s)
                 return __parse_numa_zonelist_order(s);
         return 0;
 }
 early_param("numa_zonelist_order", setup_numa_zonelist_order);
 
 /*
  * sysctl handler for numa_zonelist_order
  */
 int numa_zonelist_order_handler(ctl_table *table, int write,
                 struct file *file, void __user *buffer, size_t *length,
                 loff_t *ppos)
 {
         char saved_string[NUMA_ZONELIST_ORDER_LEN];
         int ret;
 
         if (write)
                 strncpy(saved_string, (char*)table->data,
                         NUMA_ZONELIST_ORDER_LEN);
         ret = proc_dostring(table, write, file, buffer, length, ppos);
         if (ret)
                 return ret;
         if (write) {
                 int oldval = user_zonelist_order;
                 if (__parse_numa_zonelist_order((char*)table->data)) {
                         /*
                          * bogus value.  restore saved string
                          */
                         strncpy((char*)table->data, saved_string,
                                 NUMA_ZONELIST_ORDER_LEN);
                         user_zonelist_order = oldval;
                 } else if (oldval != user_zonelist_order)
                         build_all_zonelists();
         }
         return 0;
 }
 
 
 #define MAX_NODE_LOAD (nr_online_nodes)
 static int node_load[MAX_NUMNODES];
 
 /**
  * find_next_best_node - find the next node that should appear in a given node's fallback list
  * @node: node whose fallback list we're appending
  * @used_node_mask: nodemask_t of already used nodes
  *
  * We use a number of factors to determine which is the next node that should
  * appear on a given node's fallback list.  The node should not have appeared
  * already in @node's fallback list, and it should be the next closest node
  * according to the distance array (which contains arbitrary distance values
  * from each node to each node in the system), and should also prefer nodes
  * with no CPUs, since presumably they'll have very little allocation pressure
  * on them otherwise.
  * It returns -1 if no node is found.
  */
 static int find_next_best_node(int node, nodemask_t *used_node_mask)
 {
         int n, val;
         int min_val = INT_MAX;
         int best_node = -1;
         const struct cpumask *tmp = cpumask_of_node(0);
 
         /* Use the local node if we haven't already */
         if (!node_isset(node, *used_node_mask)) {
                 node_set(node, *used_node_mask);
                 return node;
         }
 
         for_each_node_state(n, N_HIGH_MEMORY) {
 
                 /* Don't want a node to appear more than once */
                 if (node_isset(n, *used_node_mask))
                         continue;
 
                 /* Use the distance array to find the distance */
                 val = node_distance(node, n);
 
                 /* Penalize nodes under us ("prefer the next node") */
                 val += (n < node);
 
                 /* Give preference to headless and unused nodes */
                 tmp = cpumask_of_node(n);
                 if (!cpumask_empty(tmp))
                         val += PENALTY_FOR_NODE_WITH_CPUS;
 
                 /* Slight preference for less loaded node */
                 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
                 val += node_load[n];
 
                 if (val < min_val) {
                         min_val = val;
                         best_node = n;
                 }
         }
 
         if (best_node >= 0)
                 node_set(best_node, *used_node_mask);
 
         return best_node;
 }
 
 
 /*
  * Build zonelists ordered by node and zones within node.
  * This results in maximum locality--normal zone overflows into local
  * DMA zone, if any--but risks exhausting DMA zone.
  */
 static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
 {
         int j;
         struct zonelist *zonelist;
 
         zonelist = &pgdat->node_zonelists[0];
         for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
                 ;
         j = build_zonelists_node(NODE_DATA(node), zonelist, j,
                                                         MAX_NR_ZONES - 1);
         zonelist->_zonerefs[j].zone = NULL;
         zonelist->_zonerefs[j].zone_idx = 0;
 }
 
 /*
  * Build gfp_thisnode zonelists
  */
 static void build_thisnode_zonelists(pg_data_t *pgdat)
 {
         int j;
         struct zonelist *zonelist;
 
         zonelist = &pgdat->node_zonelists[1];
         j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
         zonelist->_zonerefs[j].zone = NULL;
         zonelist->_zonerefs[j].zone_idx = 0;
 }
 
 /*
  * Build zonelists ordered by zone and nodes within zones.
  * This results in conserving DMA zone[s] until all Normal memory is
  * exhausted, but results in overflowing to remote node while memory
  * may still exist in local DMA zone.
  */
 static int node_order[MAX_NUMNODES];
 
 static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
 {
         int pos, j, node;
         int zone_type;          /* needs to be signed */
         struct zone *z;
         struct zonelist *zonelist;
 
         zonelist = &pgdat->node_zonelists[0];
         pos = 0;
         for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
                 for (j = 0; j < nr_nodes; j++) {
                         node = node_order[j];
                         z = &NODE_DATA(node)->node_zones[zone_type];
                         if (populated_zone(z)) {
                                 zoneref_set_zone(z,
                                         &zonelist->_zonerefs[pos++]);
                                 check_highest_zone(zone_type);
                         }
                 }
         }
         zonelist->_zonerefs[pos].zone = NULL;
         zonelist->_zonerefs[pos].zone_idx = 0;
 }
 
 static int default_zonelist_order(void)
 {
         int nid, zone_type;
         unsigned long low_kmem_size,total_size;
         struct zone *z;
         int average_size;
         /*
          * ZONE_DMA and ZONE_DMA32 can be very small area in the sytem.
          * If they are really small and used heavily, the system can fall
          * into OOM very easily.
          * This function detect ZONE_DMA/DMA32 size and confgigures zone order.
          */
         /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
         low_kmem_size = 0;
         total_size = 0;
         for_each_online_node(nid) {
                 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
                         z = &NODE_DATA(nid)->node_zones[zone_type];
                         if (populated_zone(z)) {
                                 if (zone_type < ZONE_NORMAL)
                                         low_kmem_size += z->present_pages;
                                 total_size += z->present_pages;
                         }
                 }
         }
         if (!low_kmem_size ||  /* there are no DMA area. */
             low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
                 return ZONELIST_ORDER_NODE;
         /*
          * look into each node's config.
          * If there is a node whose DMA/DMA32 memory is very big area on
          * local memory, NODE_ORDER may be suitable.
          */
         average_size = total_size /
                                 (nodes_weight(node_states[N_HIGH_MEMORY]) + 1);
         for_each_online_node(nid) {
                 low_kmem_size = 0;
                 total_size = 0;
                 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
                         z = &NODE_DATA(nid)->node_zones[zone_type];
                         if (populated_zone(z)) {
                                 if (zone_type < ZONE_NORMAL)
                                         low_kmem_size += z->present_pages;
                                 total_size += z->present_pages;
                         }
                 }
                 if (low_kmem_size &&
                     total_size > average_size && /* ignore small node */
                     low_kmem_size > total_size * 70/100)
                         return ZONELIST_ORDER_NODE;
         }
         return ZONELIST_ORDER_ZONE;
 }
 
 static void set_zonelist_order(void)
 {
         if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
                 current_zonelist_order = default_zonelist_order();
         else
                 current_zonelist_order = user_zonelist_order;
 }
 
 static void build_zonelists(pg_data_t *pgdat)
 {
         int j, node, load;
         enum zone_type i;
         nodemask_t used_mask;
         int local_node, prev_node;
         struct zonelist *zonelist;
         int order = current_zonelist_order;
 
         /* initialize zonelists */
         for (i = 0; i < MAX_ZONELISTS; i++) {
                 zonelist = pgdat->node_zonelists + i;
                 zonelist->_zonerefs[0].zone = NULL;
                 zonelist->_zonerefs[0].zone_idx = 0;
         }
 
         /* NUMA-aware ordering of nodes */
         local_node = pgdat->node_id;
         load = nr_online_nodes;
         prev_node = local_node;
         nodes_clear(used_mask);
 
         memset(node_order, 0, sizeof(node_order));
         j = 0;
 
         while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
                 int distance = node_distance(local_node, node);
 
                 /*
                  * If another node is sufficiently far away then it is better
                  * to reclaim pages in a zone before going off node.
                  */
                 if (distance > RECLAIM_DISTANCE)
                         zone_reclaim_mode = 1;
 
                 /*
                  * We don't want to pressure a particular node.
                  * So adding penalty to the first node in same
                  * distance group to make it round-robin.
                  */
                 if (distance != node_distance(local_node, prev_node))
                         node_load[node] = load;
 
                 prev_node = node;
                 load--;
                 if (order == ZONELIST_ORDER_NODE)
                         build_zonelists_in_node_order(pgdat, node);
                 else
                         node_order[j++] = node; /* remember order */
         }
 
         if (order == ZONELIST_ORDER_ZONE) {
                 /* calculate node order -- i.e., DMA last! */
                 build_zonelists_in_zone_order(pgdat, j);
         }
 
         build_thisnode_zonelists(pgdat);
 }
 
 /* Construct the zonelist performance cache - see further mmzone.h */
 static void build_zonelist_cache(pg_data_t *pgdat)
 {
         struct zonelist *zonelist;
         struct zonelist_cache *zlc;
         struct zoneref *z;
 
         zonelist = &pgdat->node_zonelists[0];
         zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
         bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
         for (z = zonelist->_zonerefs; z->zone; z++)
                 zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
 }
 
 
 #else   /* CONFIG_NUMA */
 
 static void set_zonelist_order(void)
 {
         current_zonelist_order = ZONELIST_ORDER_ZONE;
 }
 
 static void build_zonelists(pg_data_t *pgdat)
 {
         int node, local_node;
         enum zone_type j;
         struct zonelist *zonelist;
 
         local_node = pgdat->node_id;
 
         zonelist = &pgdat->node_zonelists[0];
         j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
 
         /*
          * Now we build the zonelist so that it contains the zones
          * of all the other nodes.
          * We don't want to pressure a particular node, so when
          * building the zones for node N, we make sure that the
          * zones coming right after the local ones are those from
          * node N+1 (modulo N)
          */
         for (node = local_node + 1; node < MAX_NUMNODES; node++) {
                 if (!node_online(node))
                         continue;
                 j = build_zonelists_node(NODE_DATA(node), zonelist, j,
                                                         MAX_NR_ZONES - 1);
         }
         for (node = 0; node < local_node; node++) {
                 if (!node_online(node))
                         continue;
                 j = build_zonelists_node(NODE_DATA(node), zonelist, j,
                                                         MAX_NR_ZONES - 1);
         }
 
         zonelist->_zonerefs[j].zone = NULL;
         zonelist->_zonerefs[j].zone_idx = 0;
 }
 
 /* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
 static void build_zonelist_cache(pg_data_t *pgdat)
 {
         pgdat->node_zonelists[0].zlcache_ptr = NULL;
 }
 
 #endif  /* CONFIG_NUMA */
 
 /* return values int ....just for stop_machine() */
 static int __build_all_zonelists(void *dummy)
 {
         int nid;
 
 #ifdef CONFIG_NUMA
         memset(node_load, 0, sizeof(node_load));
 #endif
         for_each_online_node(nid) {
                 pg_data_t *pgdat = NODE_DATA(nid);
 
                 build_zonelists(pgdat);
                 build_zonelist_cache(pgdat);
         }
         return 0;
 }
 
 void build_all_zonelists(void)
 {
         set_zonelist_order();
 
         if (system_state == SYSTEM_BOOTING) {
                 __build_all_zonelists(NULL);
                 mminit_verify_zonelist();
                 cpuset_init_current_mems_allowed();
         } else {
                 /* we have to stop all cpus to guarantee there is no user
                    of zonelist */
                 stop_machine(__build_all_zonelists, NULL, NULL);
                 /* cpuset refresh routine should be here */
         }
         vm_total_pages = nr_free_pagecache_pages();
         /*
          * Disable grouping by mobility if the number of pages in the
          * system is too low to allow the mechanism to work. It would be
          * more accurate, but expensive to check per-zone. This check is
          * made on memory-hotadd so a system can start with mobility
          * disabled and enable it later
          */
         if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
                 page_group_by_mobility_disabled = 1;
         else
                 page_group_by_mobility_disabled = 0;
 
         printk("Built %i zonelists in %s order, mobility grouping %s.  "
                 "Total pages: %ld\n",
                         nr_online_nodes,
                         zonelist_order_name[current_zonelist_order],
                         page_group_by_mobility_disabled ? "off" : "on",
                         vm_total_pages);
 #ifdef CONFIG_NUMA
         printk("Policy zone: %s\n", zone_names[policy_zone]);
 #endif
 }
 
 /*
  * Helper functions to size the waitqueue hash table.
  * Essentially these want to choose hash table sizes sufficiently
  * large so that collisions trying to wait on pages are rare.
  * But in fact, the number of active page waitqueues on typical
  * systems is ridiculously low, less than 200. So this is even
  * conservative, even though it seems large.
  *
  * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
  * waitqueues, i.e. the size of the waitq table given the number of pages.
  */
 #define PAGES_PER_WAITQUEUE     256
 
 #ifndef CONFIG_MEMORY_HOTPLUG
 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
 {
         unsigned long size = 1;
 
         pages /= PAGES_PER_WAITQUEUE;
 
         while (size < pages)
                 size <<= 1;
 
         /*
          * Once we have dozens or even hundreds of threads sleeping
          * on IO we've got bigger problems than wait queue collision.
          * Limit the size of the wait table to a reasonable size.
          */
         size = min(size, 4096UL);
 
         return max(size, 4UL);
 }
 #else
 /*
  * A zone's size might be changed by hot-add, so it is not possible to determine
  * a suitable size for its wait_table.  So we use the maximum size now.
  *
  * The max wait table size = 4096 x sizeof(wait_queue_head_t).   ie:
  *
  *    i386 (preemption config)    : 4096 x 16 = 64Kbyte.
  *    ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
  *    ia64, x86-64 (preemption)   : 4096 x 24 = 96Kbyte.
  *
  * The maximum entries are prepared when a zone's memory is (512K + 256) pages
  * or more by the traditional way. (See above).  It equals:
  *
  *    i386, x86-64, powerpc(4K page size) : =  ( 2G + 1M)byte.
  *    ia64(16K page size)                 : =  ( 8G + 4M)byte.
  *    powerpc (64K page size)             : =  (32G +16M)byte.
  */
 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
 {
         return 4096UL;
 }
 #endif
 
 /*
  * This is an integer logarithm so that shifts can be used later
  * to extract the more random high bits from the multiplicative
  * hash function before the remainder is taken.
  */
 static inline unsigned long wait_table_bits(unsigned long size)
 {
         return ffz(~size);
 }
 
 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
 
 /*
  * Mark a number of pageblocks as MIGRATE_RESERVE. The number
  * of blocks reserved is based on min_wmark_pages(zone). The memory within
  * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
  * higher will lead to a bigger reserve which will get freed as contiguous
  * blocks as reclaim kicks in
  */
 static void setup_zone_migrate_reserve(struct zone *zone)
 {
         unsigned long start_pfn, pfn, end_pfn;
         struct page *page;
         unsigned long block_migratetype;
         int reserve;
 
         /* Get the start pfn, end pfn and the number of blocks to reserve */
         start_pfn = zone->zone_start_pfn;
         end_pfn = start_pfn + zone->spanned_pages;
         reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
                                                         pageblock_order;
 
         /*
          * Reserve blocks are generally in place to help high-order atomic
          * allocations that are short-lived. A min_free_kbytes value that
          * would result in more than 2 reserve blocks for atomic allocations
          * is assumed to be in place to help anti-fragmentation for the
          * future allocation of hugepages at runtime.
          */
         reserve = min(2, reserve);
 
         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
                 if (!pfn_valid(pfn))
                         continue;
                 page = pfn_to_page(pfn);
 
                 /* Watch out for overlapping nodes */
                 if (page_to_nid(page) != zone_to_nid(zone))
                         continue;
 
                 /* Blocks with reserved pages will never free, skip them. */
                 if (PageReserved(page))
                         continue;
 
                 block_migratetype = get_pageblock_migratetype(page);
 
                 /* If this block is reserved, account for it */
                 if (reserve > 0 && block_migratetype == MIGRATE_RESERVE) {
                         reserve--;
                         continue;
                 }
 
                 /* Suitable for reserving if this block is movable */
                 if (reserve > 0 && block_migratetype == MIGRATE_MOVABLE) {
                         set_pageblock_migratetype(page, MIGRATE_RESERVE);
                         move_freepages_block(zone, page, MIGRATE_RESERVE);
                         reserve--;
                         continue;
                 }
 
                 /*
                  * If the reserve is met and this is a previous reserved block,
                  * take it back
                  */
                 if (block_migratetype == MIGRATE_RESERVE) {
                         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
                         move_freepages_block(zone, page, MIGRATE_MOVABLE);
                 }
         }
 }
 
 /*
  * Initially all pages are reserved - free ones are freed
  * up by free_all_bootmem() once the early boot process is
  * done. Non-atomic initialization, single-pass.
  */
 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
                 unsigned long start_pfn, enum memmap_context context)
 {
         struct page *page;
         unsigned long end_pfn = start_pfn + size;
         unsigned long pfn;
         struct zone *z;
 
         if (highest_memmap_pfn < end_pfn - 1)
                 highest_memmap_pfn = end_pfn - 1;
 
         z = &NODE_DATA(nid)->node_zones[zone];
         for (pfn = start_pfn; pfn < end_pfn; pfn++) {
                 /*
                  * There can be holes in boot-time mem_map[]s
                  * handed to this function.  They do not
                  * exist on hotplugged memory.
                  */
                 if (context == MEMMAP_EARLY) {
                         if (!early_pfn_valid(pfn))
                                 continue;
                         if (!early_pfn_in_nid(pfn, nid))
                                 continue;
                 }
                 page = pfn_to_page(pfn);
                 set_page_links(page, zone, nid, pfn);
                 mminit_verify_page_links(page, zone, nid, pfn);
                 init_page_count(page);
                 reset_page_mapcount(page);
                 SetPageReserved(page);
                 /*
                  * Mark the block movable so that blocks are reserved for
                  * movable at startup. This will force kernel allocations
                  * to reserve their blocks rather than leaking throughout
                  * the address space during boot when many long-lived
                  * kernel allocations are made. Later some blocks near
                  * the start are marked MIGRATE_RESERVE by
                  * setup_zone_migrate_reserve()
                  *
                  * bitmap is created for zone's valid pfn range. but memmap
                  * can be created for invalid pages (for alignment)
                  * check here not to call set_pageblock_migratetype() against
                  * pfn out of zone.
                  */
                 if ((z->zone_start_pfn <= pfn)
                     && (pfn < z->zone_start_pfn + z->spanned_pages)
                     && !(pfn & (pageblock_nr_pages - 1)))
                         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
 
                 INIT_LIST_HEAD(&page->lru);
 #ifdef WANT_PAGE_VIRTUAL
                 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
                 if (!is_highmem_idx(zone))
                         set_page_address(page, __va(pfn << PAGE_SHIFT));
 #endif
         }
 }
 
 static void __meminit zone_init_free_lists(struct zone *zone)
 {
         int order, t;
         for_each_migratetype_order(order, t) {
                 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
                 zone->free_area[order].nr_free = 0;
         }
 }
 
 #ifndef __HAVE_ARCH_MEMMAP_INIT
 #define memmap_init(size, nid, zone, start_pfn) \
         memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
 #endif
 
 static int zone_batchsize(struct zone *zone)
 {
 #ifdef CONFIG_MMU
         int batch;
 
         /*
          * The per-cpu-pages pools are set to around 1000th of the
          * size of the zone.  But no more than 1/2 of a meg.
          *
          * OK, so we don't know how big the cache is.  So guess.
          */
         batch = zone->present_pages / 1024;
         if (batch * PAGE_SIZE > 512 * 1024)
                 batch = (512 * 1024) / PAGE_SIZE;
         batch /= 4;             /* We effectively *= 4 below */
         if (batch < 1)
                 batch = 1;
 
         /*
          * Clamp the batch to a 2^n - 1 value. Having a power
          * of 2 value was found to be more likely to have
          * suboptimal cache aliasing properties in some cases.
          *
          * For example if 2 tasks are alternately allocating
          * batches of pages, one task can end up with a lot
          * of pages of one half of the possible page colors
          * and the other with pages of the other colors.
          */
         batch = rounddown_pow_of_two(batch + batch/2) - 1;
 
         return batch;
 
 #else
         /* The deferral and batching of frees should be suppressed under NOMMU
          * conditions.
          *
          * The problem is that NOMMU needs to be able to allocate large chunks
          * of contiguous memory as there's no hardware page translation to
          * assemble apparent contiguous memory from discontiguous pages.
          *
          * Queueing large contiguous runs of pages for batching, however,
          * causes the pages to actually be freed in smaller chunks.  As there
          * can be a significant delay between the individual batches being
          * recycled, this leads to the once large chunks of space being
          * fragmented and becoming unavailable for high-order allocations.
          */
         return 0;
 #endif
 }
 
 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
 {
         struct per_cpu_pages *pcp;
 
         memset(p, 0, sizeof(*p));
 
         pcp = &p->pcp;
         pcp->count = 0;
         pcp->high = 6 * batch;
         pcp->batch = max(1UL, 1 * batch);
         INIT_LIST_HEAD(&pcp->list);
 }
 
 /*
  * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
  * to the value high for the pageset p.
  */
 
 static void setup_pagelist_highmark(struct per_cpu_pageset *p,
                                 unsigned long high)
 {
         struct per_cpu_pages *pcp;
 
         pcp = &p->pcp;
         pcp->high = high;
         pcp->batch = max(1UL, high/4);
         if ((high/4) > (PAGE_SHIFT * 8))
                 pcp->batch = PAGE_SHIFT * 8;
 }
 
 
 #ifdef CONFIG_NUMA
 /*
  * Boot pageset table. One per cpu which is going to be used for all
  * zones and all nodes. The parameters will be set in such a way
  * that an item put on a list will immediately be handed over to
  * the buddy list. This is safe since pageset manipulation is done
  * with interrupts disabled.
  *
  * Some NUMA counter updates may also be caught by the boot pagesets.
  *
  * The boot_pagesets must be kept even after bootup is complete for
  * unused processors and/or zones. They do play a role for bootstrapping
  * hotplugged processors.
  *
  * zoneinfo_show() and maybe other functions do
  * not check if the processor is online before following the pageset pointer.
  * Other parts of the kernel may not check if the zone is available.
  */
 static struct per_cpu_pageset boot_pageset[NR_CPUS];
 
 /*
  * Dynamically allocate memory for the
  * per cpu pageset array in struct zone.
  */
 static int __cpuinit process_zones(int cpu)
 {
         struct zone *zone, *dzone;
         int node = cpu_to_node(cpu);
 
         node_set_state(node, N_CPU);    /* this node has a cpu */
 
         for_each_populated_zone(zone) {
                 zone_pcp(zone, cpu) = kmalloc_node(sizeof(struct per_cpu_pageset),
                                          GFP_KERNEL, node);
                 if (!zone_pcp(zone, cpu))
                         goto bad;
 
                 setup_pageset(zone_pcp(zone, cpu), zone_batchsize(zone));
 
                 if (percpu_pagelist_fraction)
                         setup_pagelist_highmark(zone_pcp(zone, cpu),
                                 (zone->present_pages / percpu_pagelist_fraction));
         }
 
         return 0;
 bad:
         for_each_zone(dzone) {
                 if (!populated_zone(dzone))
                         continue;
                 if (dzone == zone)
                         break;
                 kfree(zone_pcp(dzone, cpu));
                 zone_pcp(dzone, cpu) = &boot_pageset[cpu];
         }
         return -ENOMEM;
 }
 
 static inline void free_zone_pagesets(int cpu)
 {
         struct zone *zone;
 
         for_each_zone(zone) {
                 struct per_cpu_pageset *pset = zone_pcp(zone, cpu);
 
                 /* Free per_cpu_pageset if it is slab allocated */
                 if (pset != &boot_pageset[cpu])
                         kfree(pset);
                 zone_pcp(zone, cpu) = &boot_pageset[cpu];
         }
 }
 
 static int __cpuinit pageset_cpuup_callback(struct notifier_block *nfb,
                 unsigned long action,
                 void *hcpu)
 {
         int cpu = (long)hcpu;
         int ret = NOTIFY_OK;
 
         switch (action) {
         case CPU_UP_PREPARE:
         case CPU_UP_PREPARE_FROZEN:
                 if (process_zones(cpu))
                         ret = NOTIFY_BAD;
                 break;
         case CPU_UP_CANCELED:
         case CPU_UP_CANCELED_FROZEN:
         case CPU_DEAD:
         case CPU_DEAD_FROZEN:
                 free_zone_pagesets(cpu);
                 break;
         default:
                 break;
         }
         return ret;
 }
 
 static struct notifier_block __cpuinitdata pageset_notifier =
         { &pageset_cpuup_callback, NULL, 0 };
 
 void __init setup_per_cpu_pageset(void)
 {
         int err;
 
         /* Initialize per_cpu_pageset for cpu 0.
          * A cpuup callback will do this for every cpu
          * as it comes online
          */
         err = process_zones(smp_processor_id());
         BUG_ON(err);
         register_cpu_notifier(&pageset_notifier);
 }
 
 #endif
 
 static noinline __init_refok
 int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
 {
         int i;
         struct pglist_data *pgdat = zone->zone_pgdat;
         size_t alloc_size;
 
         /*
          * The per-page waitqueue mechanism uses hashed waitqueues
          * per zone.
          */
         zone->wait_table_hash_nr_entries =
                  wait_table_hash_nr_entries(zone_size_pages);
         zone->wait_table_bits =
                 wait_table_bits(zone->wait_table_hash_nr_entries);
         alloc_size = zone->wait_table_hash_nr_entries
                                         * sizeof(wait_queue_head_t);
 
         if (!slab_is_available()) {
                 zone->wait_table = (wait_queue_head_t *)
                         alloc_bootmem_node(pgdat, alloc_size);
         } else {
                 /*
                  * This case means that a zone whose size was 0 gets new memory
                  * via memory hot-add.
                  * But it may be the case that a new node was hot-added.  In
                  * this case vmalloc() will not be able to use this new node's
                  * memory - this wait_table must be initialized to use this new
                  * node itself as well.
                  * To use this new node's memory, further consideration will be
                  * necessary.
                  */
                 zone->wait_table = vmalloc(alloc_size);
         }
         if (!zone->wait_table)
                 return -ENOMEM;
 
         for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
                 init_waitqueue_head(zone->wait_table + i);
 
         return 0;
 }
 
 static __meminit void zone_pcp_init(struct zone *zone)
 {
         int cpu;
         unsigned long batch = zone_batchsize(zone);
 
         for (cpu = 0; cpu < NR_CPUS; cpu++) {
 #ifdef CONFIG_NUMA
                 /* Early boot. Slab allocator not functional yet */
                 zone_pcp(zone, cpu) = &boot_pageset[cpu];
                 setup_pageset(&boot_pageset[cpu],0);
 #else
                 setup_pageset(zone_pcp(zone,cpu), batch);
 #endif
         }
         if (zone->present_pages)
                 printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%lu\n",
                         zone->name, zone->present_pages, batch);
 }
 
 __meminit int init_currently_empty_zone(struct zone *zone,
                                         unsigned long zone_start_pfn,
                                         unsigned long size,
                                         enum memmap_context context)
 {
         struct pglist_data *pgdat = zone->zone_pgdat;
         int ret;
         ret = zone_wait_table_init(zone, size);
         if (ret)
                 return ret;
         pgdat->nr_zones = zone_idx(zone) + 1;
 
         zone->zone_start_pfn = zone_start_pfn;
 
         mminit_dprintk(MMINIT_TRACE, "memmap_init",
                         "Initialising map node %d zone %lu pfns %lu -> %lu\n",
                         pgdat->node_id,
                         (unsigned long)zone_idx(zone),
                         zone_start_pfn, (zone_start_pfn + size));
 
         zone_init_free_lists(zone);
 
         return 0;
 }
 
 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
 /*
  * Basic iterator support. Return the first range of PFNs for a node
  * Note: nid == MAX_NUMNODES returns first region regardless of node
  */
 static int __meminit first_active_region_index_in_nid(int nid)
 {
         int i;
 
         for (i = 0; i < nr_nodemap_entries; i++)
                 if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
                         return i;
 
         return -1;
 }
 
 /*
  * Basic iterator support. Return the next active range of PFNs for a node
  * Note: nid == MAX_NUMNODES returns next region regardless of node
  */
 static int __meminit next_active_region_index_in_nid(int index, int nid)
 {
         for (index = index + 1; index < nr_nodemap_entries; index++)
                 if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
                         return index;
 
         return -1;
 }
 
 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
 /*
  * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
  * Architectures may implement their own version but if add_active_range()
  * was used and there are no special requirements, this is a convenient
  * alternative
  */
 int __meminit __early_pfn_to_nid(unsigned long pfn)
 {
         int i;
 
         for (i = 0; i < nr_nodemap_entries; i++) {
                 unsigned long start_pfn = early_node_map[i].start_pfn;
                 unsigned long end_pfn = early_node_map[i].end_pfn;
 
                 if (start_pfn <= pfn && pfn < end_pfn)
                         return early_node_map[i].nid;
         }
         /* This is a memory hole */
         return -1;
 }
 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
 
 int __meminit early_pfn_to_nid(unsigned long pfn)
 {
         int nid;
 
         nid = __early_pfn_to_nid(pfn);
         if (nid >= 0)
                 return nid;
         /* just returns 0 */
         return 0;
 }
 
 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
 bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
 {
         int nid;
 
         nid = __early_pfn_to_nid(pfn);
         if (nid >= 0 && nid != node)
                 return false;
         return true;
 }
 #endif
 
 /* Basic iterator support to walk early_node_map[] */
 #define for_each_active_range_index_in_nid(i, nid) \
         for (i = first_active_region_index_in_nid(nid); i != -1; \
                                 i = next_active_region_index_in_nid(i, nid))
 
 /**
  * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
  * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
  * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
  *
  * If an architecture guarantees that all ranges registered with
  * add_active_ranges() contain no holes and may be freed, this
  * this function may be used instead of calling free_bootmem() manually.
  */
 void __init free_bootmem_with_active_regions(int nid,
                                                 unsigned long max_low_pfn)
 {
         int i;
 
         for_each_active_range_index_in_nid(i, nid) {
                 unsigned long size_pages = 0;
                 unsigned long end_pfn = early_node_map[i].end_pfn;
 
                 if (early_node_map[i].start_pfn >= max_low_pfn)
                         continue;
 
                 if (end_pfn > max_low_pfn)
                         end_pfn = max_low_pfn;
 
                 size_pages = end_pfn - early_node_map[i].start_pfn;
                 free_bootmem_node(NODE_DATA(early_node_map[i].nid),
                                 PFN_PHYS(early_node_map[i].start_pfn),
                                 size_pages << PAGE_SHIFT);
         }
 }
 
 void __init work_with_active_regions(int nid, work_fn_t work_fn, void *data)
 {
         int i;
         int ret;
 
         for_each_active_range_index_in_nid(i, nid) {
                 ret = work_fn(early_node_map[i].start_pfn,
                               early_node_map[i].end_pfn, data);
                 if (ret)
                         break;
         }
 }
 /**
  * sparse_memory_present_with_active_regions - Call memory_present for each active range
  * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
  *
  * If an architecture guarantees that all ranges registered with
  * add_active_ranges() contain no holes and may be freed, this
  * function may be used instead of calling memory_present() manually.
  */
 void __init sparse_memory_present_with_active_regions(int nid)
 {
         int i;
 
         for_each_active_range_index_in_nid(i, nid)
                 memory_present(early_node_map[i].nid,
                                 early_node_map[i].start_pfn,
                                 early_node_map[i].end_pfn);
 }
 
 /**
  * get_pfn_range_for_nid - Return the start and end page frames for a node
  * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
  * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
  * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
  *
  * It returns the start and end page frame of a node based on information
  * provided by an arch calling add_active_range(). If called for a node
  * with no available memory, a warning is printed and the start and end
  * PFNs will be 0.
  */
 void __meminit get_pfn_range_for_nid(unsigned int nid,
                         unsigned long *start_pfn, unsigned long *end_pfn)
 {
         int i;
         *start_pfn = -1UL;
         *end_pfn = 0;
 
         for_each_active_range_index_in_nid(i, nid) {
                 *start_pfn = min(*start_pfn, early_node_map[i].start_pfn);
                 *end_pfn = max(*end_pfn, early_node_map[i].end_pfn);
         }
 
         if (*start_pfn == -1UL)
                 *start_pfn = 0;
 }
 
 /*
  * This finds a zone that can be used for ZONE_MOVABLE pages. The
  * assumption is made that zones within a node are ordered in monotonic
  * increasing memory addresses so that the "highest" populated zone is used
  */
 static void __init find_usable_zone_for_movable(void)
 {
         int zone_index;
         for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
                 if (zone_index == ZONE_MOVABLE)
                         continue;
 
                 if (arch_zone_highest_possible_pfn[zone_index] >
                                 arch_zone_lowest_possible_pfn[zone_index])
                         break;
         }
 
         VM_BUG_ON(zone_index == -1);
         movable_zone = zone_index;
 }
 
 /*
  * The zone ranges provided by the architecture do not include ZONE_MOVABLE
  * because it is sized independant of architecture. Unlike the other zones,
  * the starting point for ZONE_MOVABLE is not fixed. It may be different
  * in each node depending on the size of each node and how evenly kernelcore
  * is distributed. This helper function adjusts the zone ranges
  * provided by the architecture for a given node by using the end of the
  * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
  * zones within a node are in order of monotonic increases memory addresses
  */
 static void __meminit adjust_zone_range_for_zone_movable(int nid,
                                         unsigned long zone_type,
                                         unsigned long node_start_pfn,
                                         unsigned long node_end_pfn,
                                         unsigned long *zone_start_pfn,
                                         unsigned long *zone_end_pfn)
 {
         /* Only adjust if ZONE_MOVABLE is on this node */
         if (zone_movable_pfn[nid]) {
                 /* Size ZONE_MOVABLE */
                 if (zone_type == ZONE_MOVABLE) {
                         *zone_start_pfn = zone_movable_pfn[nid];
                         *zone_end_pfn = min(node_end_pfn,
                                 arch_zone_highest_possible_pfn[movable_zone]);
 
                 /* Adjust for ZONE_MOVABLE starting within this range */
                 } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
                                 *zone_end_pfn > zone_movable_pfn[nid]) {
                         *zone_end_pfn = zone_movable_pfn[nid];
 
                 /* Check if this whole range is within ZONE_MOVABLE */
                 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
                         *zone_start_pfn = *zone_end_pfn;
         }
 }
 
 /*
  * Return the number of pages a zone spans in a node, including holes
  * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
  */
 static unsigned long __meminit zone_spanned_pages_in_node(int nid,
                                         unsigned long zone_type,
                                         unsigned long *ignored)
 {
         unsigned long node_start_pfn, node_end_pfn;
         unsigned long zone_start_pfn, zone_end_pfn;
 
         /* Get the start and end of the node and zone */
         get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
         zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
         zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
         adjust_zone_range_for_zone_movable(nid, zone_type,
                                 node_start_pfn, node_end_pfn,
                                 &zone_start_pfn, &zone_end_pfn);
 
         /* Check that this node has pages within the zone's required range */
         if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
                 return 0;
 
         /* Move the zone boundaries inside the node if necessary */
         zone_end_pfn = min(zone_end_pfn, node_end_pfn);
         zone_start_pfn = max(zone_start_pfn, node_start_pfn);
 
         /* Return the spanned pages */
         return zone_end_pfn - zone_start_pfn;
 }
 
 /*
  * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
  * then all holes in the requested range will be accounted for.
  */
 static unsigned long __meminit __absent_pages_in_range(int nid,
                                 unsigned long range_start_pfn,
                                 unsigned long range_end_pfn)
 {
         int i = 0;
         unsigned long prev_end_pfn = 0, hole_pages = 0;
         unsigned long start_pfn;
 
         /* Find the end_pfn of the first active range of pfns in the node */
         i = first_active_region_index_in_nid(nid);
         if (i == -1)
                 return 0;
 
         prev_end_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
 
         /* Account for ranges before physical memory on this node */
         if (early_node_map[i].start_pfn > range_start_pfn)
                 hole_pages = prev_end_pfn - range_start_pfn;
 
         /* Find all holes for the zone within the node */
         for (; i != -1; i = next_active_region_index_in_nid(i, nid)) {
 
                 /* No need to continue if prev_end_pfn is outside the zone */
                 if (prev_end_pfn >= range_end_pfn)
                         break;
 
                 /* Make sure the end of the zone is not within the hole */
                 start_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
                 prev_end_pfn = max(prev_end_pfn, range_start_pfn);
 
                 /* Update the hole size cound and move on */
                 if (start_pfn > range_start_pfn) {
                         BUG_ON(prev_end_pfn > start_pfn);
                         hole_pages += start_pfn - prev_end_pfn;
                 }
                 prev_end_pfn = early_node_map[i].end_pfn;
         }
 
         /* Account for ranges past physical memory on this node */
         if (range_end_pfn > prev_end_pfn)
                 hole_pages += range_end_pfn -
                                 max(range_start_pfn, prev_end_pfn);
 
         return hole_pages;
 }
 
 /**
  * absent_pages_in_range - Return number of page frames in holes within a range
  * @start_pfn: The start PFN to start searching for holes
  * @end_pfn: The end PFN to stop searching for holes
  *
  * It returns the number of pages frames in memory holes within a range.
  */
 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
                                                         unsigned long end_pfn)
 {
         return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
 }
 
 /* Return the number of page frames in holes in a zone on a node */
 static unsigned long __meminit zone_absent_pages_in_node(int nid,
                                         unsigned long zone_type,
                                         unsigned long *ignored)
 {
         unsigned long node_start_pfn, node_end_pfn;
         unsigned long zone_start_pfn, zone_end_pfn;
 
         get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
         zone_start_pfn = max(arch_zone_lowest_possible_pfn[zone_type],
                                                         node_start_pfn);
         zone_end_pfn = min(arch_zone_highest_possible_pfn[zone_type],
                                                         node_end_pfn);
 
         adjust_zone_range_for_zone_movable(nid, zone_type,
                         node_start_pfn, node_end_pfn,
                         &zone_start_pfn, &zone_end_pfn);
         return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
 }
 
 #else
 static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
                                         unsigned long zone_type,
                                         unsigned long *zones_size)
 {
         return zones_size[zone_type];
 }
 
 static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
                                                 unsigned long zone_type,
                                                 unsigned long *zholes_size)
 {
         if (!zholes_size)
                 return 0;
 
         return zholes_size[zone_type];
 }
 
 #endif
 
 static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
                 unsigned long *zones_size, unsigned long *zholes_size)
 {
         unsigned long realtotalpages, totalpages = 0;
         enum zone_type i;
 
         for (i = 0; i < MAX_NR_ZONES; i++)
                 totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
                                                                 zones_size);
         pgdat->node_spanned_pages = totalpages;
 
         realtotalpages = totalpages;
         for (i = 0; i < MAX_NR_ZONES; i++)
                 realtotalpages -=
                         zone_absent_pages_in_node(pgdat->node_id, i,
                                                                 zholes_size);
         pgdat->node_present_pages = realtotalpages;
         printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
                                                         realtotalpages);
 }
 
 #ifndef CONFIG_SPARSEMEM
 /*
  * Calculate the size of the zone->blockflags rounded to an unsigned long
  * Start by making sure zonesize is a multiple of pageblock_order by rounding
  * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
  * round what is now in bits to nearest long in bits, then return it in
  * bytes.
  */
 static unsigned long __init usemap_size(unsigned long zonesize)
 {
         unsigned long usemapsize;
 
         usemapsize = roundup(zonesize, pageblock_nr_pages);
         usemapsize = usemapsize >> pageblock_order;
         usemapsize *= NR_PAGEBLOCK_BITS;
         usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
 
         return usemapsize / 8;
 }
 
 static void __init setup_usemap(struct pglist_data *pgdat,
                                 struct zone *zone, unsigned long zonesize)
 {
         unsigned long usemapsize = usemap_size(zonesize);
         zone->pageblock_flags = NULL;
         if (usemapsize)
                 zone->pageblock_flags = alloc_bootmem_node(pgdat, usemapsize);
 }
 #else
 static void inline setup_usemap(struct pglist_data *pgdat,
                                 struct zone *zone, unsigned long zonesize) {}
 #endif /* CONFIG_SPARSEMEM */
 
 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
 
 /* Return a sensible default order for the pageblock size. */
 static inline int pageblock_default_order(void)
 {
         if (HPAGE_SHIFT > PAGE_SHIFT)
                 return HUGETLB_PAGE_ORDER;
 
         return MAX_ORDER-1;
 }
 
 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
 static inline void __init set_pageblock_order(unsigned int order)
 {
         /* Check that pageblock_nr_pages has not already been setup */
         if (pageblock_order)
                 return;
 
         /*
          * Assume the largest contiguous order of interest is a huge page.
          * This value may be variable depending on boot parameters on IA64
          */
         pageblock_order = order;
 }
 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
 
 /*
  * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
  * and pageblock_default_order() are unused as pageblock_order is set
  * at compile-time. See include/linux/pageblock-flags.h for the values of
  * pageblock_order based on the kernel config
  */
 static inline int pageblock_default_order(unsigned int order)
 {
         return MAX_ORDER-1;
 }
 #define set_pageblock_order(x)  do {} while (0)
 
 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
 
 /*
  * Set up the zone data structures:
  *   - mark all pages reserved
  *   - mark all memory queues empty
  *   - clear the memory bitmaps
  */
 static void __paginginit free_area_init_core(struct pglist_data *pgdat,
                 unsigned long *zones_size, unsigned long *zholes_size)
 {
         enum zone_type j;
         int nid = pgdat->node_id;
         unsigned long zone_start_pfn = pgdat->node_start_pfn;
         int ret;
 
         pgdat_resize_init(pgdat);
         pgdat->nr_zones = 0;
         init_waitqueue_head(&pgdat->kswapd_wait);
         pgdat->kswapd_max_order = 0;
         pgdat_page_cgroup_init(pgdat);
         
         for (j = 0; j < MAX_NR_ZONES; j++) {
                 struct zone *zone = pgdat->node_zones + j;
                 unsigned long size, realsize, memmap_pages;
                 enum lru_list l;
 
                 size = zone_spanned_pages_in_node(nid, j, zones_size);
                 realsize = size - zone_absent_pages_in_node(nid, j,
                                                                 zholes_size);
 
                 /*
                  * Adjust realsize so that it accounts for how much memory
                  * is used by this zone for memmap. This affects the watermark
                  * and per-cpu initialisations
                  */
                 memmap_pages =
                         PAGE_ALIGN(size * sizeof(struct page)) >> PAGE_SHIFT;
                 if (realsize >= memmap_pages) {
                         realsize -= memmap_pages;
                         if (memmap_pages)
                                 printk(KERN_DEBUG
                                        "  %s zone: %lu pages used for memmap\n",
                                        zone_names[j], memmap_pages);
                 } else
                         printk(KERN_WARNING
                                 "  %s zone: %lu pages exceeds realsize %lu\n",
                                 zone_names[j], memmap_pages, realsize);
 
                 /* Account for reserved pages */
                 if (j == 0 && realsize > dma_reserve) {
                         realsize -= dma_reserve;
                         printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
                                         zone_names[0], dma_reserve);
                 }
 
                 if (!is_highmem_idx(j))
                         nr_kernel_pages += realsize;
                 nr_all_pages += realsize;
 
                 zone->spanned_pages = size;
                 zone->present_pages = realsize;
 #ifdef CONFIG_NUMA
                 zone->node = nid;
                 zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
                                                 / 100;
                 zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
 #endif
                 zone->name = zone_names[j];
                 spin_lock_init(&zone->lock);
                 spin_lock_init(&zone->lru_lock);
                 zone_seqlock_init(zone);
                 zone->zone_pgdat = pgdat;
 
                 zone->prev_priority = DEF_PRIORITY;
 
                 zone_pcp_init(zone);
                 for_each_lru(l) {
                         INIT_LIST_HEAD(&zone->lru[l].list);
                         zone->lru[l].nr_saved_scan = 0;
                 }
                 zone->reclaim_stat.recent_rotated[0] = 0;
                 zone->reclaim_stat.recent_rotated[1] = 0;
                 zone->reclaim_stat.recent_scanned[0] = 0;
                 zone->reclaim_stat.recent_scanned[1] = 0;
                 zap_zone_vm_stats(zone);
                 zone->flags = 0;
                 if (!size)
                         continue;
 
                 set_pageblock_order(pageblock_default_order());
                 setup_usemap(pgdat, zone, size);
                 ret = init_currently_empty_zone(zone, zone_start_pfn,
                                                 size, MEMMAP_EARLY);
                 BUG_ON(ret);
                 memmap_init(size, nid, j, zone_start_pfn);
                 zone_start_pfn += size;
         }
 }
 
 static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
 {
         /* Skip empty nodes */
         if (!pgdat->node_spanned_pages)
                 return;
 
 #ifdef CONFIG_FLAT_NODE_MEM_MAP
         /* ia64 gets its own node_mem_map, before this, without bootmem */
         if (!pgdat->node_mem_map) {
                 unsigned long size, start, end;
                 struct page *map;
 
                 /*
                  * The zone's endpoints aren't required to be MAX_ORDER
                  * aligned but the node_mem_map endpoints must be in order
                  * for the buddy allocator to function correctly.
                  */
                 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
                 end = pgdat->node_start_pfn + pgdat->node_spanned_pages;
                 end = ALIGN(end, MAX_ORDER_NR_PAGES);
                 size =  (end - start) * sizeof(struct page);
                 map = alloc_remap(pgdat->node_id, size);
                 if (!map)
                         map = alloc_bootmem_node(pgdat, size);
                 pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
         }
 #ifndef CONFIG_NEED_MULTIPLE_NODES
         /*
          * With no DISCONTIG, the global mem_map is just set as node 0's
          */
         if (pgdat == NODE_DATA(0)) {
                 mem_map = NODE_DATA(0)->node_mem_map;
 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
                 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
                         mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
         }
 #endif
 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
 }
 
 void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
                 unsigned long node_start_pfn, unsigned long *zholes_size)
 {
         pg_data_t *pgdat = NODE_DATA(nid);
 
         pgdat->node_id = nid;
         pgdat->node_start_pfn = node_start_pfn;
         calculate_node_totalpages(pgdat, zones_size, zholes_size);
 
         alloc_node_mem_map(pgdat);
 #ifdef CONFIG_FLAT_NODE_MEM_MAP
         printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
                 nid, (unsigned long)pgdat,
                 (unsigned long)pgdat->node_mem_map);
 #endif
 
         free_area_init_core(pgdat, zones_size, zholes_size);
 }
 
 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
 
 #if MAX_NUMNODES > 1
 /*
  * Figure out the number of possible node ids.
  */
 static void __init setup_nr_node_ids(void)
 {
         unsigned int node;
         unsigned int highest = 0;
 
         for_each_node_mask(node, node_possible_map)
                 highest = node;
         nr_node_ids = highest + 1;
 }
 #else
 static inline void setup_nr_node_ids(void)
 {
 }
 #endif
 
 /**
  * add_active_range - Register a range of PFNs backed by physical memory
  * @nid: The node ID the range resides on
  * @start_pfn: The start PFN of the available physical memory
  * @end_pfn: The end PFN of the available physical memory
  *
  * These ranges are stored in an early_node_map[] and later used by
  * free_area_init_nodes() to calculate zone sizes and holes. If the
  * range spans a memory hole, it is up to the architecture to ensure
  * the memory is not freed by the bootmem allocator. If possible
  * the range being registered will be merged with existing ranges.
  */
 void __init add_active_range(unsigned int nid, unsigned long start_pfn,
                                                 unsigned long end_pfn)
 {
         int i;
 
         mminit_dprintk(MMINIT_TRACE, "memory_register",
                         "Entering add_active_range(%d, %#lx, %#lx) "
                         "%d entries of %d used\n",
                         nid, start_pfn, end_pfn,
                         nr_nodemap_entries, MAX_ACTIVE_REGIONS);
 
         mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
 
         /* Merge with existing active regions if possible */
         for (i = 0; i < nr_nodemap_entries; i++) {
                 if (early_node_map[i].nid != nid)
                         continue;
 
                 /* Skip if an existing region covers this new one */
                 if (start_pfn >= early_node_map[i].start_pfn &&
                                 end_pfn <= early_node_map[i].end_pfn)
                         return;
 
                 /* Merge forward if suitable */
                 if (start_pfn <= early_node_map[i].end_pfn &&
                                 end_pfn > early_node_map[i].end_pfn) {
                         early_node_map[i].end_pfn = end_pfn;
                         return;
                 }
 
                 /* Merge backward if suitable */
                 if (start_pfn < early_node_map[i].end_pfn &&
                                 end_pfn >= early_node_map[i].start_pfn) {
                         early_node_map[i].start_pfn = start_pfn;
                         return;
                 }
         }
 
         /* Check that early_node_map is large enough */
         if (i >= MAX_ACTIVE_REGIONS) {
                 printk(KERN_CRIT "More than %d memory regions, truncating\n",
                                                         MAX_ACTIVE_REGIONS);
                 return;
         }
 
         early_node_map[i].nid = nid;
         early_node_map[i].start_pfn = start_pfn;
         early_node_map[i].end_pfn = end_pfn;
         nr_nodemap_entries = i + 1;
 }
 
 /**
  * remove_active_range - Shrink an existing registered range of PFNs
  * @nid: The node id the range is on that should be shrunk
  * @start_pfn: The new PFN of the range
  * @end_pfn: The new PFN of the range
  *
  * i386 with NUMA use alloc_remap() to store a node_mem_map on a local node.
  * The map is kept near the end physical page range that has already been
  * registered. This function allows an arch to shrink an existing registered
  * range.
  */
 void __init remove_active_range(unsigned int nid, unsigned long start_pfn,
                                 unsigned long end_pfn)
 {
         int i, j;
         int removed = 0;
 
         printk(KERN_DEBUG "remove_active_range (%d, %lu, %lu)\n",
                           nid, start_pfn, end_pfn);
 
         /* Find the old active region end and shrink */
         for_each_active_range_index_in_nid(i, nid) {
                 if (early_node_map[i].start_pfn >= start_pfn &&
                     early_node_map[i].end_pfn <= end_pfn) {
                         /* clear it */
                         early_node_map[i].start_pfn = 0;
                         early_node_map[i].end_pfn = 0;
                         removed = 1;
                         continue;
                 }
                 if (early_node_map[i].start_pfn < start_pfn &&
                     early_node_map[i].end_pfn > start_pfn) {
                         unsigned long temp_end_pfn = early_node_map[i].end_pfn;
                         early_node_map[i].end_pfn = start_pfn;
                         if (temp_end_pfn > end_pfn)
                                 add_active_range(nid, end_pfn, temp_end_pfn);
                         continue;
                 }
                 if (early_node_map[i].start_pfn >= start_pfn &&
                     early_node_map[i].end_pfn > end_pfn &&
                     early_node_map[i].start_pfn < end_pfn) {
                         early_node_map[i].start_pfn = end_pfn;
                         continue;
                 }
         }
 
         if (!removed)
                 return;
 
         /* remove the blank ones */
         for (i = nr_nodemap_entries - 1; i > 0; i--) {
                 if (early_node_map[i].nid != nid)
                         continue;
                 if (early_node_map[i].end_pfn)
                         continue;
                 /* we found it, get rid of it */
                 for (j = i; j < nr_nodemap_entries - 1; j++)
                         memcpy(&early_node_map[j], &early_node_map[j+1],
                                 sizeof(early_node_map[j]));
                 j = nr_nodemap_entries - 1;
                 memset(&early_node_map[j], 0, sizeof(early_node_map[j]));
                 nr_nodemap_entries--;
         }
 }
 
 /**
  * remove_all_active_ranges - Remove all currently registered regions
  *
  * During discovery, it may be found that a table like SRAT is invalid
  * and an alternative discovery method must be used. This function removes
  * all currently registered regions.
  */
 void __init remove_all_active_ranges(void)
 {
         memset(early_node_map, 0, sizeof(early_node_map));
         nr_nodemap_entries = 0;
 }
 
 /* Compare two active node_active_regions */
 static int __init cmp_node_active_region(const void *a, const void *b)
 {
         struct node_active_region *arange = (struct node_active_region *)a;
         struct node_active_region *brange = (struct node_active_region *)b;
 
         /* Done this way to avoid overflows */
         if (arange->start_pfn > brange->start_pfn)
                 return 1;
         if (arange->start_pfn < brange->start_pfn)
                 return -1;
 
         return 0;
 }
 
 /* sort the node_map by start_pfn */
 static void __init sort_node_map(void)
 {
         sort(early_node_map, (size_t)nr_nodemap_entries,
                         sizeof(struct node_active_region),
                         cmp_node_active_region, NULL);
 }
 
 /* Find the lowest pfn for a node */
 static unsigned long __init find_min_pfn_for_node(int nid)
 {
         int i;
         unsigned long min_pfn = ULONG_MAX;
 
         /* Assuming a sorted map, the first range found has the starting pfn */
         for_each_active_range_index_in_nid(i, nid)
                 min_pfn = min(min_pfn, early_node_map[i].start_pfn);
 
         if (min_pfn == ULONG_MAX) {
                 printk(KERN_WARNING
                         "Could not find start_pfn for node %d\n", nid);
                 return 0;
         }
 
         return min_pfn;
 }
 
 /**
  * find_min_pfn_with_active_regions - Find the minimum PFN registered
  *
  * It returns the minimum PFN based on information provided via
  * add_active_range().
  */
 unsigned long __init find_min_pfn_with_active_regions(void)
 {
         return find_min_pfn_for_node(MAX_NUMNODES);
 }
 
 /*
  * early_calculate_totalpages()
  * Sum pages in active regions for movable zone.
  * Populate N_HIGH_MEMORY for calculating usable_nodes.
  */
 static unsigned long __init early_calculate_totalpages(void)
 {
         int i;
         unsigned long totalpages = 0;
 
         for (i = 0; i < nr_nodemap_entries; i++) {
                 unsigned long pages = early_node_map[i].end_pfn -
                                                 early_node_map[i].start_pfn;
                 totalpages += pages;
                 if (pages)
                         node_set_state(early_node_map[i].nid, N_HIGH_MEMORY);
         }
         return totalpages;
 }
 
 /*
  * Find the PFN the Movable zone begins in each node. Kernel memory
  * is spread evenly between nodes as long as the nodes have enough
  * memory. When they don't, some nodes will have more kernelcore than
  * others
  */
 static void __init find_zone_movable_pfns_for_nodes(unsigned long *movable_pfn)
 {
         int i, nid;
         unsigned long usable_startpfn;
         unsigned long kernelcore_node, kernelcore_remaining;
         /* save the state before borrow the nodemask */
         nodemask_t saved_node_state = node_states[N_HIGH_MEMORY];
         unsigned long totalpages = early_calculate_totalpages();
         int usable_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
 
         /*
          * If movablecore was specified, calculate what size of
          * kernelcore that corresponds so that memory usable for
          * any allocation type is evenly spread. If both kernelcore
          * and movablecore are specified, then the value of kernelcore
          * will be used for required_kernelcore if it's greater than
          * what movablecore would have allowed.
          */
         if (required_movablecore) {
                 unsigned long corepages;
 
                 /*
                  * Round-up so that ZONE_MOVABLE is at least as large as what
                  * was requested by the user
                  */
                 required_movablecore =
                         roundup(required_movablecore, MAX_ORDER_NR_PAGES);
                 corepages = totalpages - required_movablecore;
 
                 required_kernelcore = max(required_kernelcore, corepages);
         }
 
         /* If kernelcore was not specified, there is no ZONE_MOVABLE */
         if (!required_kernelcore)
                 goto out;
 
         /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
         find_usable_zone_for_movable();
         usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
 
 restart:
         /* Spread kernelcore memory as evenly as possible throughout nodes */
         kernelcore_node = required_kernelcore / usable_nodes;
         for_each_node_state(nid, N_HIGH_MEMORY) {
                 /*
                  * Recalculate kernelcore_node if the division per node
                  * now exceeds what is necessary to satisfy the requested
                  * amount of memory for the kernel
                  */
                 if (required_kernelcore < kernelcore_node)
                         kernelcore_node = required_kernelcore / usable_nodes;
 
                 /*
                  * As the map is walked, we track how much memory is usable
                  * by the kernel using kernelcore_remaining. When it is
                  * 0, the rest of the node is usable by ZONE_MOVABLE
                  */
                 kernelcore_remaining = kernelcore_node;
 
                 /* Go through each range of PFNs within this node */
                 for_each_active_range_index_in_nid(i, nid) {
                         unsigned long start_pfn, end_pfn;
                         unsigned long size_pages;
 
                         start_pfn = max(early_node_map[i].start_pfn,
                                                 zone_movable_pfn[nid]);
                         end_pfn = early_node_map[i].end_pfn;
                         if (start_pfn >= end_pfn)
                                 continue;
 
                         /* Account for what is only usable for kernelcore */
                         if (start_pfn < usable_startpfn) {
                                 unsigned long kernel_pages;
                                 kernel_pages = min(end_pfn, usable_startpfn)
                                                                 - start_pfn;
 
                                 kernelcore_remaining -= min(kernel_pages,
                                                         kernelcore_remaining);
                                 required_kernelcore -= min(kernel_pages,
                                                         required_kernelcore);
 
                                 /* Continue if range is now fully accounted */
                                 if (end_pfn <= usable_startpfn) {
 
                                         /*
                                          * Push zone_movable_pfn to the end so
                                          * that if we have to rebalance
                                          * kernelcore across nodes, we will
                                          * not double account here
                                          */
                                         zone_movable_pfn[nid] = end_pfn;
                                         continue;
                                 }
                                 start_pfn = usable_startpfn;
                         }
 
                         /*
                          * The usable PFN range for ZONE_MOVABLE is from
                          * start_pfn->end_pfn. Calculate size_pages as the
                          * number of pages used as kernelcore
                          */
                         size_pages = end_pfn - start_pfn;
                         if (size_pages > kernelcore_remaining)
                                 size_pages = kernelcore_remaining;
                         zone_movable_pfn[nid] = start_pfn + size_pages;
 
                         /*
                          * Some kernelcore has been met, update counts and
                          * break if the kernelcore for this node has been
                          * satisified
                          */
                         required_kernelcore -= min(required_kernelcore,
                                                                 size_pages);
                         kernelcore_remaining -= size_pages;
                         if (!kernelcore_remaining)
                                 break;
                 }
         }
 
         /*
          * If there is still required_kernelcore, we do another pass with one
          * less node in the count. This will push zone_movable_pfn[nid] further
          * along on the nodes that still have memory until kernelcore is
          * satisified
          */
         usable_nodes--;
         if (usable_nodes && required_kernelcore > usable_nodes)
                 goto restart;
 
         /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
         for (nid = 0; nid < MAX_NUMNODES; nid++)
                 zone_movable_pfn[nid] =
                         roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
 
 out:
         /* restore the node_state */
         node_states[N_HIGH_MEMORY] = saved_node_state;
 }
 
 /* Any regular memory on that node ? */
 static void check_for_regular_memory(pg_data_t *pgdat)
 {
 #ifdef CONFIG_HIGHMEM
         enum zone_type zone_type;
 
         for (zone_type = 0; zone_type <= ZONE_NORMAL; zone_type++) {
                 struct zone *zone = &pgdat->node_zones[zone_type];
                 if (zone->present_pages)
                         node_set_state(zone_to_nid(zone), N_NORMAL_MEMORY);
         }
 #endif
 }
 
 /**
  * free_area_init_nodes - Initialise all pg_data_t and zone data
  * @max_zone_pfn: an array of max PFNs for each zone
  *
  * This will call free_area_init_node() for each active node in the system.
  * Using the page ranges provided by add_active_range(), the size of each
  * zone in each node and their holes is calculated. If the maximum PFN
  * between two adjacent zones match, it is assumed that the zone is empty.
  * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
  * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
  * starts where the previous one ended. For example, ZONE_DMA32 starts
  * at arch_max_dma_pfn.
  */
 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
 {
         unsigned long nid;
         int i;
 
         /* Sort early_node_map as initialisation assumes it is sorted */
         sort_node_map();
 
         /* Record where the zone boundaries are */
         memset(arch_zone_lowest_possible_pfn, 0,
                                 sizeof(arch_zone_lowest_possible_pfn));
         memset(arch_zone_highest_possible_pfn, 0,
                                 sizeof(arch_zone_highest_possible_pfn));
         arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
         arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
         for (i = 1; i < MAX_NR_ZONES; i++) {
                 if (i == ZONE_MOVABLE)
                         continue;
                 arch_zone_lowest_possible_pfn[i] =
                         arch_zone_highest_possible_pfn[i-1];
                 arch_zone_highest_possible_pfn[i] =
                         max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
         }
         arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
         arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
 
         /* Find the PFNs that ZONE_MOVABLE begins at in each node */
         memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
         find_zone_movable_pfns_for_nodes(zone_movable_pfn);
 
         /* Print out the zone ranges */
         printk("Zone PFN ranges:\n");
         for (i = 0; i < MAX_NR_ZONES; i++) {
                 if (i == ZONE_MOVABLE)
                         continue;
                 printk("  %-8s %0#10lx -> %0#10lx\n",
                                 zone_names[i],
                                 arch_zone_lowest_possible_pfn[i],
                                 arch_zone_highest_possible_pfn[i]);
         }
 
         /* Print out the PFNs ZONE_MOVABLE begins at in each node */
         printk("Movable zone start PFN for each node\n");
         for (i = 0; i < MAX_NUMNODES; i++) {
                 if (zone_movable_pfn[i])
                         printk("  Node %d: %lu\n", i, zone_movable_pfn[i]);
         }
 
         /* Print out the early_node_map[] */
         printk("early_node_map[%d] active PFN ranges\n", nr_nodemap_entries);
         for (i = 0; i < nr_nodemap_entries; i++)
                 printk("  %3d: %0#10lx -> %0#10lx\n", early_node_map[i].nid,
                                                 early_node_map[i].start_pfn,
                                                 early_node_map[i].end_pfn);
 
         /* Initialise every node */
         mminit_verify_pageflags_layout();
         setup_nr_node_ids();
         for_each_online_node(nid) {
                 pg_data_t *pgdat = NODE_DATA(nid);
                 free_area_init_node(nid, NULL,
                                 find_min_pfn_for_node(nid), NULL);
 
                 /* Any memory on that node */
                 if (pgdat->node_present_pages)
                         node_set_state(nid, N_HIGH_MEMORY);
                 check_for_regular_memory(pgdat);
         }
 }
 
 static int __init cmdline_parse_core(char *p, unsigned long *core)
 {
         unsigned long long coremem;
         if (!p)
                 return -EINVAL;
 
         coremem = memparse(p, &p);
         *core = coremem >> PAGE_SHIFT;
 
         /* Paranoid check that UL is enough for the coremem value */
         WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
 
         return 0;
 }
 
 /*
  * kernelcore=size sets the amount of memory for use for allocations that
  * cannot be reclaimed or migrated.
  */
 static int __init cmdline_parse_kernelcore(char *p)
 {
         return cmdline_parse_core(p, &required_kernelcore);
 }
 
 /*
  * movablecore=size sets the amount of memory for use for allocations that
  * can be reclaimed or migrated.
  */
 static int __init cmdline_parse_movablecore(char *p)
 {
         return cmdline_parse_core(p, &required_movablecore);
 }
 
 early_param("kernelcore", cmdline_parse_kernelcore);
 early_param("movablecore", cmdline_parse_movablecore);
 
 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
 
 /**
  * set_dma_reserve - set the specified number of pages reserved in the first zone
  * @new_dma_reserve: The number of pages to mark reserved
  *
  * The per-cpu batchsize and zone watermarks are determined by present_pages.
  * In the DMA zone, a significant percentage may be consumed by kernel image
  * and other unfreeable allocations which can skew the watermarks badly. This
  * function may optionally be used to account for unfreeable pages in the
  * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
  * smaller per-cpu batchsize.
  */
 void __init set_dma_reserve(unsigned long new_dma_reserve)
 {
         dma_reserve = new_dma_reserve;
 }
 
 #ifndef CONFIG_NEED_MULTIPLE_NODES
 struct pglist_data __refdata contig_page_data = { .bdata = &bootmem_node_data[0] };
 EXPORT_SYMBOL(contig_page_data);
 #endif
 
 void __init free_area_init(unsigned long *zones_size)
 {
         free_area_init_node(0, zones_size,
                         __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
 }
 
 static int page_alloc_cpu_notify(struct notifier_block *self,
                                  unsigned long action, void *hcpu)
 {
         int cpu = (unsigned long)hcpu;
 
         if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
                 drain_pages(cpu);
 
                 /*
                  * Spill the event counters of the dead processor
                  * into the current processors event counters.
                  * This artificially elevates the count of the current
                  * processor.
                  */
                 vm_events_fold_cpu(cpu);
 
                 /*
                  * Zero the differential counters of the dead processor
                  * so that the vm statistics are consistent.
                  *
                  * This is only okay since the processor is dead and cannot
                  * race with what we are doing.
                  */
                 refresh_cpu_vm_stats(cpu);
         }
         return NOTIFY_OK;
 }
 
 void __init page_alloc_init(void)
 {
         hotcpu_notifier(page_alloc_cpu_notify, 0);
 }
 
 /*
  * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
  *      or min_free_kbytes changes.
  */
 static void calculate_totalreserve_pages(void)
 {
         struct pglist_data *pgdat;
         unsigned long reserve_pages = 0;
         enum zone_type i, j;
 
         for_each_online_pgdat(pgdat) {
                 for (i = 0; i < MAX_NR_ZONES; i++) {
                         struct zone *zone = pgdat->node_zones + i;
                         unsigned long max = 0;
 
                         /* Find valid and maximum lowmem_reserve in the zone */
                         for (j = i; j < MAX_NR_ZONES; j++) {
                                 if (zone->lowmem_reserve[j] > max)
                                         max = zone->lowmem_reserve[j];
                         }
 
                         /* we treat the high watermark as reserved pages. */
                         max += high_wmark_pages(zone);
 
                         if (max > zone->present_pages)
                                 max = zone->present_pages;
                         reserve_pages += max;
                 }
         }
         totalreserve_pages = reserve_pages;
 }
 
 /*
  * setup_per_zone_lowmem_reserve - called whenever
  *      sysctl_lower_zone_reserve_ratio changes.  Ensures that each zone
  *      has a correct pages reserved value, so an adequate number of
  *      pages are left in the zone after a successful __alloc_pages().
  */
 static void setup_per_zone_lowmem_reserve(void)
 {
         struct pglist_data *pgdat;
         enum zone_type j, idx;
 
         for_each_online_pgdat(pgdat) {
                 for (j = 0; j < MAX_NR_ZONES; j++) {
                         struct zone *zone = pgdat->node_zones + j;
                         unsigned long present_pages = zone->present_pages;
 
                         zone->lowmem_reserve[j] = 0;
 
                         idx = j;
                         while (idx) {
                                 struct zone *lower_zone;
 
                                 idx--;
 
                                 if (sysctl_lowmem_reserve_ratio[idx] < 1)
                                         sysctl_lowmem_reserve_ratio[idx] = 1;
 
                                 lower_zone = pgdat->node_zones + idx;
                                 lower_zone->lowmem_reserve[j] = present_pages /
                                         sysctl_lowmem_reserve_ratio[idx];
                                 present_pages += lower_zone->present_pages;
                         }
                 }
         }
 
         /* update totalreserve_pages */
         calculate_totalreserve_pages();
 }
 
 /**
  * setup_per_zone_wmarks - called when min_free_kbytes changes
  * or when memory is hot-{added|removed}
  *
  * Ensures that the watermark[min,low,high] values for each zone are set
  * correctly with respect to min_free_kbytes.
  */
 void setup_per_zone_wmarks(void)
 {
         unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
         unsigned long lowmem_pages = 0;
         struct zone *zone;
         unsigned long flags;
 
         /* Calculate total number of !ZONE_HIGHMEM pages */
         for_each_zone(zone) {
                 if (!is_highmem(zone))
                         lowmem_pages += zone->present_pages;
         }
 
         for_each_zone(zone) {
                 u64 tmp;
 
                 spin_lock_irqsave(&zone->lock, flags);
                 tmp = (u64)pages_min * zone->present_pages;
                 do_div(tmp, lowmem_pages);
                 if (is_highmem(zone)) {
                         /*
                          * __GFP_HIGH and PF_MEMALLOC allocations usually don't
                          * need highmem pages, so cap pages_min to a small
                          * value here.
                          *
                          * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
                          * deltas controls asynch page reclaim, and so should
                          * not be capped for highmem.
                          */
                         int min_pages;
 
                         min_pages = zone->present_pages / 1024;
                         if (min_pages < SWAP_CLUSTER_MAX)
                                 min_pages = SWAP_CLUSTER_MAX;
                         if (min_pages > 128)
                                 min_pages = 128;
                         zone->watermark[WMARK_MIN] = min_pages;
                 } else {
                         /*
                          * If it's a lowmem zone, reserve a number of pages
                          * proportionate to the zone's size.
                          */
                         zone->watermark[WMARK_MIN] = tmp;
                 }
 
                 zone->watermark[WMARK_LOW]  = min_wmark_pages(zone) + (tmp >> 2);
                 zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
                 setup_zone_migrate_reserve(zone);
                 spin_unlock_irqrestore(&zone->lock, flags);
         }
 
         /* update totalreserve_pages */
         calculate_totalreserve_pages();
 }
 
 /**
  * The inactive anon list should be small enough that the VM never has to
  * do too much work, but large enough that each inactive page has a chance
  * to be referenced again before it is swapped out.
  *
  * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
  * INACTIVE_ANON pages on this zone's LRU, maintained by the
  * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
  * the anonymous pages are kept on the inactive list.
  *
  * total     target    max
  * memory    ratio     inactive anon
  * -------------------------------------
  *   10MB       1         5MB
  *  100MB       1        50MB
  *    1GB       3       250MB
  *   10GB      10       0.9GB
  *  100GB      31         3GB
  *    1TB     101        10GB
  *   10TB     320        32GB
  */
 void calculate_zone_inactive_ratio(struct zone *zone)
 {
         unsigned int gb, ratio;
 
         /* Zone size in gigabytes */
         gb = zone->present_pages >> (30 - PAGE_SHIFT);
         if (gb)
                 ratio = int_sqrt(10 * gb);
         else
                 ratio = 1;
 
         zone->inactive_ratio = ratio;
 }
 
 static void __init setup_per_zone_inactive_ratio(void)
 {
         struct zone *zone;
 
         for_each_zone(zone)
                 calculate_zone_inactive_ratio(zone);
 }
 
 /*
  * Initialise min_free_kbytes.
  *
  * For small machines we want it small (128k min).  For large machines
  * we want it large (64MB max).  But it is not linear, because network
  * bandwidth does not increase linearly with machine size.  We use
  *
  *      min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
  *      min_free_kbytes = sqrt(lowmem_kbytes * 16)
  *
  * which yields
  *
  * 16MB:        512k
  * 32MB:        724k
  * 64MB:        1024k
  * 128MB:       1448k
  * 256MB:       2048k
  * 512MB:       2896k
  * 1024MB:      4096k
  * 2048MB:      5792k
  * 4096MB:      8192k
  * 8192MB:      11584k
  * 16384MB:     16384k
  */
 static int __init init_per_zone_wmark_min(void)
 {
         unsigned long lowmem_kbytes;
 
         lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
 
         min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
         if (min_free_kbytes < 128)
                 min_free_kbytes = 128;
         if (min_free_kbytes > 65536)
                 min_free_kbytes = 65536;
         setup_per_zone_wmarks();
         setup_per_zone_lowmem_reserve();
         setup_per_zone_inactive_ratio();
         return 0;
 }
 module_init(init_per_zone_wmark_min)
 
 /*
  * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so 
  *      that we can call two helper functions whenever min_free_kbytes
  *      changes.
  */
 int min_free_kbytes_sysctl_handler(ctl_table *table, int write, 
         struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
 {
         proc_dointvec(table, write, file, buffer, length, ppos);
         if (write)
                 setup_per_zone_wmarks();
         return 0;
 }
 
 #ifdef CONFIG_NUMA
 int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
         struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
 {
         struct zone *zone;
         int rc;
 
         rc = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
         if (rc)
                 return rc;
 
         for_each_zone(zone)
                 zone->min_unmapped_pages = (zone->present_pages *
                                 sysctl_min_unmapped_ratio) / 100;
         return 0;
 }
 
 int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
         struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
 {
         struct zone *zone;
         int rc;
 
         rc = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
         if (rc)
                 return rc;
 
         for_each_zone(zone)
                 zone->min_slab_pages = (zone->present_pages *
                                 sysctl_min_slab_ratio) / 100;
         return 0;
 }
 #endif
 
 /*
  * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
  *      proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
  *      whenever sysctl_lowmem_reserve_ratio changes.
  *
  * The reserve ratio obviously has absolutely no relation with the
  * minimum watermarks. The lowmem reserve ratio can only make sense
  * if in function of the boot time zone sizes.
  */
 int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
         struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
 {
         proc_dointvec_minmax(table, write, file, buffer, length, ppos);
         setup_per_zone_lowmem_reserve();
         return 0;
 }
 
 /*
  * percpu_pagelist_fraction - changes the pcp->high for each zone on each
  * cpu.  It is the fraction of total pages in each zone that a hot per cpu pagelist
  * can have before it gets flushed back to buddy allocator.
  */
 
 int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
         struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
 {
         struct zone *zone;
         unsigned int cpu;
         int ret;
 
         ret = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
         if (!write || (ret == -EINVAL))
                 return ret;
         for_each_populated_zone(zone) {
                 for_each_online_cpu(cpu) {
                         unsigned long  high;
                         high = zone->present_pages / percpu_pagelist_fraction;
                         setup_pagelist_highmark(zone_pcp(zone, cpu), high);
                 }
         }
         return 0;
 }
 
 int hashdist = HASHDIST_DEFAULT;
 
 #ifdef CONFIG_NUMA
 static int __init set_hashdist(char *str)
 {
         if (!str)
                 return 0;
         hashdist = simple_strtoul(str, &str, 0);
         return 1;
 }
 __setup("hashdist=", set_hashdist);
 #endif
 
 /*
  * allocate a large system hash table from bootmem
  * - it is assumed that the hash table must contain an exact power-of-2
  *   quantity of entries
  * - limit is the number of hash buckets, not the total allocation size
  */
 void *__init alloc_large_system_hash(const char *tablename,
                                      unsigned long bucketsize,
                                      unsigned long numentries,
                                      int scale,
                                      int flags,
                                      unsigned int *_hash_shift,
                                      unsigned int *_hash_mask,
                                      unsigned long limit)
 {
         unsigned long long max = limit;
         unsigned long log2qty, size;
         void *table = NULL;
 
         /* allow the kernel cmdline to have a say */
         if (!numentries) {
                 /* round applicable memory size up to nearest megabyte */
                 numentries = nr_kernel_pages;
                 numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
                 numentries >>= 20 - PAGE_SHIFT;
                 numentries <<= 20 - PAGE_SHIFT;
 
                 /* limit to 1 bucket per 2^scale bytes of low memory */
                 if (scale > PAGE_SHIFT)
                         numentries >>= (scale - PAGE_SHIFT);
                 else
                         numentries <<= (PAGE_SHIFT - scale);
 
                 /* Make sure we've got at least a 0-order allocation.. */
                 if (unlikely((numentries * bucketsize) < PAGE_SIZE))
                         numentries = PAGE_SIZE / bucketsize;
         }
         numentries = roundup_pow_of_two(numentries);
 
         /* limit allocation size to 1/16 total memory by default */
         if (max == 0) {
                 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
                 do_div(max, bucketsize);
         }
 
         if (numentries > max)
                 numentries = max;
 
         log2qty = ilog2(numentries);
 
         do {
                 size = bucketsize << log2qty;
                 if (flags & HASH_EARLY)
                         table = alloc_bootmem_nopanic(size);
                 else if (hashdist)
                         table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
                 else {
                         /*
                          * If bucketsize is not a power-of-two, we may free
                          * some pages at the end of hash table which
                          * alloc_pages_exact() automatically does
                          */
                         if (get_order(size) < MAX_ORDER) {
                                 table = alloc_pages_exact(size, GFP_ATOMIC);
                                 kmemleak_alloc(table, size, 1, GFP_ATOMIC);
                         }
                 }
         } while (!table && size > PAGE_SIZE && --log2qty);
 
         if (!table)
                 panic("Failed to allocate %s hash table\n", tablename);
 
         printk(KERN_INFO "%s hash table entries: %d (order: %d, %lu bytes)\n",
                tablename,
                (1U << log2qty),
                ilog2(size) - PAGE_SHIFT,
                size);
 
         if (_hash_shift)
                 *_hash_shift = log2qty;
         if (_hash_mask)
                 *_hash_mask = (1 << log2qty) - 1;
 
         return table;
 }
 
 /* Return a pointer to the bitmap storing bits affecting a block of pages */
 static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
                                                         unsigned long pfn)
 {
 #ifdef CONFIG_SPARSEMEM
         return __pfn_to_section(pfn)->pageblock_flags;
 #else
         return zone->pageblock_flags;
 #endif /* CONFIG_SPARSEMEM */
 }
 
 static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
 {
 #ifdef CONFIG_SPARSEMEM
         pfn &= (PAGES_PER_SECTION-1);
         return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
 #else
         pfn = pfn - zone->zone_start_pfn;
         return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
 #endif /* CONFIG_SPARSEMEM */
 }
 
 /**
  * get_pageblock_flags_group - Return the requested group of flags for the pageblock_nr_pages block of pages
  * @page: The page within the block of interest
  * @start_bitidx: The first bit of interest to retrieve
  * @end_bitidx: The last bit of interest
  * returns pageblock_bits flags
  */
 unsigned long get_pageblock_flags_group(struct page *page,
                                         int start_bitidx, int end_bitidx)
 {
         struct zone *zone;
         unsigned long *bitmap;
         unsigned long pfn, bitidx;
         unsigned long flags = 0;
         unsigned long value = 1;
 
         zone = page_zone(page);
         pfn = page_to_pfn(page);
         bitmap = get_pageblock_bitmap(zone, pfn);
         bitidx = pfn_to_bitidx(zone, pfn);
 
         for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
                 if (test_bit(bitidx + start_bitidx, bitmap))
                         flags |= value;
 
         return flags;
 }
 
 /**
  * set_pageblock_flags_group - Set the requested group of flags for a pageblock_nr_pages block of pages
  * @page: The page within the block of interest
  * @start_bitidx: The first bit of interest
  * @end_bitidx: The last bit of interest
  * @flags: The flags to set
  */
 void set_pageblock_flags_group(struct page *page, unsigned long flags,
                                         int start_bitidx, int end_bitidx)
 {
         struct zone *zone;
         unsigned long *bitmap;
         unsigned long pfn, bitidx;
         unsigned long value = 1;
 
         zone = page_zone(page);
         pfn = page_to_pfn(page);
         bitmap = get_pageblock_bitmap(zone, pfn);
         bitidx = pfn_to_bitidx(zone, pfn);
         VM_BUG_ON(pfn < zone->zone_start_pfn);
         VM_BUG_ON(pfn >= zone->zone_start_pfn + zone->spanned_pages);
 
         for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
                 if (flags & value)
                         __set_bit(bitidx + start_bitidx, bitmap);
                 else
                         __clear_bit(bitidx + start_bitidx, bitmap);
 }
 
 /*
  * This is designed as sub function...plz see page_isolation.c also.
  * set/clear page block's type to be ISOLATE.
  * page allocater never alloc memory from ISOLATE block.
  */
 
 int set_migratetype_isolate(struct page *page)
 {
         struct zone *zone;
         unsigned long flags;
         int ret = -EBUSY;
 
         zone = page_zone(page);
         spin_lock_irqsave(&zone->lock, flags);
         /*
          * In future, more migrate types will be able to be isolation target.
          */
         if (get_pageblock_migratetype(page) != MIGRATE_MOVABLE)
                 goto out;
         set_pageblock_migratetype(page, MIGRATE_ISOLATE);
         move_freepages_block(zone, page, MIGRATE_ISOLATE);
         ret = 0;
 out:
         spin_unlock_irqrestore(&zone->lock, flags);
         if (!ret)
                 drain_all_pages();
         return ret;
 }
 
 void unset_migratetype_isolate(struct page *page)
 {
         struct zone *zone;
         unsigned long flags;
         zone = page_zone(page);
         spin_lock_irqsave(&zone->lock, flags);
         if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
                 goto out;
         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
         move_freepages_block(zone, page, MIGRATE_MOVABLE);
 out:
         spin_unlock_irqrestore(&zone->lock, flags);
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
 /*
  * All pages in the range must be isolated before calling this.
  */
 void
 __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 {
         struct page *page;
         struct zone *zone;
         int order, i;
         unsigned long pfn;
         unsigned long flags;
         /* find the first valid pfn */
         for (pfn = start_pfn; pfn < end_pfn; pfn++)
                 if (pfn_valid(pfn))
                         break;
         if (pfn == end_pfn)
                 return;
         zone = page_zone(pfn_to_page(pfn));
         spin_lock_irqsave(&zone->lock, flags);
         pfn = start_pfn;
         while (pfn < end_pfn) {
                 if (!pfn_valid(pfn)) {
                         pfn++;
                         continue;
                 }
                 page = pfn_to_page(pfn);
                 BUG_ON(page_count(page));
                 BUG_ON(!PageBuddy(page));
                 order = page_order(page);
 #ifdef CONFIG_DEBUG_VM
                 printk(KERN_INFO "remove from free list %lx %d %lx\n",
                        pfn, 1 << order, end_pfn);
 #endif
                 list_del(&page->lru);
                 rmv_page_order(page);
                 zone->free_area[order].nr_free--;
                 __mod_zone_page_state(zone, NR_FREE_PAGES,
                                       - (1UL << order));
                 for (i = 0; i < (1 << order); i++)
                         SetPageReserved((page+i));
                 pfn += (1 << order);
         }
         spin_unlock_irqrestore(&zone->lock, flags);
 }
 #endif