Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 1272 insertions, 0 deletions

diff --git a/kernel/include/linux/mmzone.h b/kernel/include/linux/mmzone.h
new file mode 100644
index 000000000..54d74f6eb
--- /dev/null
+++ b/kernel/include/linux/mmzone.h
@@ -0,0 +1,1272 @@
+#ifndef _LINUX_MMZONE_H
+#define _LINUX_MMZONE_H
+
+#ifndef __ASSEMBLY__
+#ifndef __GENERATING_BOUNDS_H
+
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+#include <linux/bitops.h>
+#include <linux/cache.h>
+#include <linux/threads.h>
+#include <linux/numa.h>
+#include <linux/init.h>
+#include <linux/seqlock.h>
+#include <linux/nodemask.h>
+#include <linux/pageblock-flags.h>
+#include <linux/page-flags-layout.h>
+#include <linux/atomic.h>
+#include <asm/page.h>
+
+/* Free memory management - zoned buddy allocator.  */
+#ifndef CONFIG_FORCE_MAX_ZONEORDER
+#define MAX_ORDER 11
+#else
+#define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
+#endif
+#define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
+
+/*
+ * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
+ * costly to service.  That is between allocation orders which should
+ * coalesce naturally under reasonable reclaim pressure and those which
+ * will not.
+ */
+#define PAGE_ALLOC_COSTLY_ORDER 3
+
+enum {
+	MIGRATE_UNMOVABLE,
+	MIGRATE_RECLAIMABLE,
+	MIGRATE_MOVABLE,
+	MIGRATE_PCPTYPES,	/* the number of types on the pcp lists */
+	MIGRATE_RESERVE = MIGRATE_PCPTYPES,
+#ifdef CONFIG_CMA
+	/*
+	 * MIGRATE_CMA migration type is designed to mimic the way
+	 * ZONE_MOVABLE works.  Only movable pages can be allocated
+	 * from MIGRATE_CMA pageblocks and page allocator never
+	 * implicitly change migration type of MIGRATE_CMA pageblock.
+	 *
+	 * The way to use it is to change migratetype of a range of
+	 * pageblocks to MIGRATE_CMA which can be done by
+	 * __free_pageblock_cma() function.  What is important though
+	 * is that a range of pageblocks must be aligned to
+	 * MAX_ORDER_NR_PAGES should biggest page be bigger then
+	 * a single pageblock.
+	 */
+	MIGRATE_CMA,
+#endif
+#ifdef CONFIG_MEMORY_ISOLATION
+	MIGRATE_ISOLATE,	/* can't allocate from here */
+#endif
+	MIGRATE_TYPES
+};
+
+#ifdef CONFIG_CMA
+#  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
+#else
+#  define is_migrate_cma(migratetype) false
+#endif
+
+#define for_each_migratetype_order(order, type) \
+	for (order = 0; order < MAX_ORDER; order++) \
+		for (type = 0; type < MIGRATE_TYPES; type++)
+
+extern int page_group_by_mobility_disabled;
+
+#define NR_MIGRATETYPE_BITS (PB_migrate_end - PB_migrate + 1)
+#define MIGRATETYPE_MASK ((1UL << NR_MIGRATETYPE_BITS) - 1)
+
+#define get_pageblock_migratetype(page)					\
+	get_pfnblock_flags_mask(page, page_to_pfn(page),		\
+			PB_migrate_end, MIGRATETYPE_MASK)
+
+static inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
+{
+	BUILD_BUG_ON(PB_migrate_end - PB_migrate != 2);
+	return get_pfnblock_flags_mask(page, pfn, PB_migrate_end,
+					MIGRATETYPE_MASK);
+}
+
+struct free_area {
+	struct list_head	free_list[MIGRATE_TYPES];
+	unsigned long		nr_free;
+};
+
+struct pglist_data;
+
+/*
+ * zone->lock and zone->lru_lock are two of the hottest locks in the kernel.
+ * So add a wild amount of padding here to ensure that they fall into separate
+ * cachelines.  There are very few zone structures in the machine, so space
+ * consumption is not a concern here.
+ */
+#if defined(CONFIG_SMP)
+struct zone_padding {
+	char x[0];
+} ____cacheline_internodealigned_in_smp;
+#define ZONE_PADDING(name)	struct zone_padding name;
+#else
+#define ZONE_PADDING(name)
+#endif
+
+enum zone_stat_item {
+	/* First 128 byte cacheline (assuming 64 bit words) */
+	NR_FREE_PAGES,
+	NR_ALLOC_BATCH,
+	NR_LRU_BASE,
+	NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
+	NR_ACTIVE_ANON,		/*  "     "     "   "       "         */
+	NR_INACTIVE_FILE,	/*  "     "     "   "       "         */
+	NR_ACTIVE_FILE,		/*  "     "     "   "       "         */
+	NR_UNEVICTABLE,		/*  "     "     "   "       "         */
+	NR_MLOCK,		/* mlock()ed pages found and moved off LRU */
+	NR_ANON_PAGES,	/* Mapped anonymous pages */
+	NR_FILE_MAPPED,	/* pagecache pages mapped into pagetables.
+			   only modified from process context */
+	NR_FILE_PAGES,
+	NR_FILE_DIRTY,
+	NR_WRITEBACK,
+	NR_SLAB_RECLAIMABLE,
+	NR_SLAB_UNRECLAIMABLE,
+	NR_PAGETABLE,		/* used for pagetables */
+	NR_KERNEL_STACK,
+	/* Second 128 byte cacheline */
+	NR_UNSTABLE_NFS,	/* NFS unstable pages */
+	NR_BOUNCE,
+	NR_VMSCAN_WRITE,
+	NR_VMSCAN_IMMEDIATE,	/* Prioritise for reclaim when writeback ends */
+	NR_WRITEBACK_TEMP,	/* Writeback using temporary buffers */
+	NR_ISOLATED_ANON,	/* Temporary isolated pages from anon lru */
+	NR_ISOLATED_FILE,	/* Temporary isolated pages from file lru */
+	NR_SHMEM,		/* shmem pages (included tmpfs/GEM pages) */
+	NR_DIRTIED,		/* page dirtyings since bootup */
+	NR_WRITTEN,		/* page writings since bootup */
+	NR_PAGES_SCANNED,	/* pages scanned since last reclaim */
+#ifdef CONFIG_NUMA
+	NUMA_HIT,		/* allocated in intended node */
+	NUMA_MISS,		/* allocated in non intended node */
+	NUMA_FOREIGN,		/* was intended here, hit elsewhere */
+	NUMA_INTERLEAVE_HIT,	/* interleaver preferred this zone */
+	NUMA_LOCAL,		/* allocation from local node */
+	NUMA_OTHER,		/* allocation from other node */
+#endif
+	WORKINGSET_REFAULT,
+	WORKINGSET_ACTIVATE,
+	WORKINGSET_NODERECLAIM,
+	NR_ANON_TRANSPARENT_HUGEPAGES,
+	NR_FREE_CMA_PAGES,
+	NR_VM_ZONE_STAT_ITEMS };
+
+/*
+ * We do arithmetic on the LRU lists in various places in the code,
+ * so it is important to keep the active lists LRU_ACTIVE higher in
+ * the array than the corresponding inactive lists, and to keep
+ * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
+ *
+ * This has to be kept in sync with the statistics in zone_stat_item
+ * above and the descriptions in vmstat_text in mm/vmstat.c
+ */
+#define LRU_BASE 0
+#define LRU_ACTIVE 1
+#define LRU_FILE 2
+
+enum lru_list {
+	LRU_INACTIVE_ANON = LRU_BASE,
+	LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
+	LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
+	LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
+	LRU_UNEVICTABLE,
+	NR_LRU_LISTS
+};
+
+#define for_each_lru(lru) for (lru = 0; lru < NR_LRU_LISTS; lru++)
+
+#define for_each_evictable_lru(lru) for (lru = 0; lru <= LRU_ACTIVE_FILE; lru++)
+
+static inline int is_file_lru(enum lru_list lru)
+{
+	return (lru == LRU_INACTIVE_FILE || lru == LRU_ACTIVE_FILE);
+}
+
+static inline int is_active_lru(enum lru_list lru)
+{
+	return (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE);
+}
+
+static inline int is_unevictable_lru(enum lru_list lru)
+{
+	return (lru == LRU_UNEVICTABLE);
+}
+
+struct zone_reclaim_stat {
+	/*
+	 * The pageout code in vmscan.c keeps track of how many of the
+	 * mem/swap backed and file backed pages are referenced.
+	 * The higher the rotated/scanned ratio, the more valuable
+	 * that cache is.
+	 *
+	 * The anon LRU stats live in [0], file LRU stats in [1]
+	 */
+	unsigned long		recent_rotated[2];
+	unsigned long		recent_scanned[2];
+};
+
+struct lruvec {
+	struct list_head lists[NR_LRU_LISTS];
+	struct zone_reclaim_stat reclaim_stat;
+#ifdef CONFIG_MEMCG
+	struct zone *zone;
+#endif
+};
+
+/* Mask used at gathering information at once (see memcontrol.c) */
+#define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
+#define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
+#define LRU_ALL	     ((1 << NR_LRU_LISTS) - 1)
+
+/* Isolate clean file */
+#define ISOLATE_CLEAN		((__force isolate_mode_t)0x1)
+/* Isolate unmapped file */
+#define ISOLATE_UNMAPPED	((__force isolate_mode_t)0x2)
+/* Isolate for asynchronous migration */
+#define ISOLATE_ASYNC_MIGRATE	((__force isolate_mode_t)0x4)
+/* Isolate unevictable pages */
+#define ISOLATE_UNEVICTABLE	((__force isolate_mode_t)0x8)
+
+/* LRU Isolation modes. */
+typedef unsigned __bitwise__ isolate_mode_t;
+
+enum zone_watermarks {
+	WMARK_MIN,
+	WMARK_LOW,
+	WMARK_HIGH,
+	NR_WMARK
+};
+
+#define min_wmark_pages(z) (z->watermark[WMARK_MIN])
+#define low_wmark_pages(z) (z->watermark[WMARK_LOW])
+#define high_wmark_pages(z) (z->watermark[WMARK_HIGH])
+
+struct per_cpu_pages {
+	int count;		/* number of pages in the list */
+	int high;		/* high watermark, emptying needed */
+	int batch;		/* chunk size for buddy add/remove */
+
+	/* Lists of pages, one per migrate type stored on the pcp-lists */
+	struct list_head lists[MIGRATE_PCPTYPES];
+};
+
+struct per_cpu_pageset {
+	struct per_cpu_pages pcp;
+#ifdef CONFIG_NUMA
+	s8 expire;
+#endif
+#ifdef CONFIG_SMP
+	s8 stat_threshold;
+	s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
+#endif
+};
+
+#endif /* !__GENERATING_BOUNDS.H */
+
+enum zone_type {
+#ifdef CONFIG_ZONE_DMA
+	/*
+	 * ZONE_DMA is used when there are devices that are not able
+	 * to do DMA to all of addressable memory (ZONE_NORMAL). Then we
+	 * carve out the portion of memory that is needed for these devices.
+	 * The range is arch specific.
+	 *
+	 * Some examples
+	 *
+	 * Architecture		Limit
+	 * ---------------------------
+	 * parisc, ia64, sparc	<4G
+	 * s390			<2G
+	 * arm			Various
+	 * alpha		Unlimited or 0-16MB.
+	 *
+	 * i386, x86_64 and multiple other arches
+	 * 			<16M.
+	 */
+	ZONE_DMA,
+#endif
+#ifdef CONFIG_ZONE_DMA32
+	/*
+	 * x86_64 needs two ZONE_DMAs because it supports devices that are
+	 * only able to do DMA to the lower 16M but also 32 bit devices that
+	 * can only do DMA areas below 4G.
+	 */
+	ZONE_DMA32,
+#endif
+	/*
+	 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be
+	 * performed on pages in ZONE_NORMAL if the DMA devices support
+	 * transfers to all addressable memory.
+	 */
+	ZONE_NORMAL,
+#ifdef CONFIG_HIGHMEM
+	/*
+	 * A memory area that is only addressable by the kernel through
+	 * mapping portions into its own address space. This is for example
+	 * used by i386 to allow the kernel to address the memory beyond
+	 * 900MB. The kernel will set up special mappings (page
+	 * table entries on i386) for each page that the kernel needs to
+	 * access.
+	 */
+	ZONE_HIGHMEM,
+#endif
+	ZONE_MOVABLE,
+	__MAX_NR_ZONES
+};
+
+#ifndef __GENERATING_BOUNDS_H
+
+struct zone {
+	/* Read-mostly fields */
+
+	/* zone watermarks, access with *_wmark_pages(zone) macros */
+	unsigned long watermark[NR_WMARK];
+
+	/*
+	 * We don't know if the memory that we're going to allocate will be freeable
+	 * or/and it will be released eventually, so to avoid totally wasting several
+	 * GB of ram we must reserve some of the lower zone memory (otherwise we risk
+	 * to run OOM on the lower zones despite there's tons of freeable ram
+	 * on the higher zones). This array is recalculated at runtime if the
+	 * sysctl_lowmem_reserve_ratio sysctl changes.
+	 */
+	long lowmem_reserve[MAX_NR_ZONES];
+
+#ifdef CONFIG_NUMA
+	int node;
+#endif
+
+	/*
+	 * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on
+	 * this zone's LRU.  Maintained by the pageout code.
+	 */
+	unsigned int inactive_ratio;
+
+	struct pglist_data	*zone_pgdat;
+	struct per_cpu_pageset __percpu *pageset;
+
+	/*
+	 * This is a per-zone reserve of pages that should not be
+	 * considered dirtyable memory.
+	 */
+	unsigned long		dirty_balance_reserve;
+
+#ifndef CONFIG_SPARSEMEM
+	/*
+	 * Flags for a pageblock_nr_pages block. See pageblock-flags.h.
+	 * In SPARSEMEM, this map is stored in struct mem_section
+	 */
+	unsigned long		*pageblock_flags;
+#endif /* CONFIG_SPARSEMEM */
+
+#ifdef CONFIG_NUMA
+	/*
+	 * zone reclaim becomes active if more unmapped pages exist.
+	 */
+	unsigned long		min_unmapped_pages;
+	unsigned long		min_slab_pages;
+#endif /* CONFIG_NUMA */
+
+	/* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
+	unsigned long		zone_start_pfn;
+
+	/*
+	 * spanned_pages is the total pages spanned by the zone, including
+	 * holes, which is calculated as:
+	 * 	spanned_pages = zone_end_pfn - zone_start_pfn;
+	 *
+	 * present_pages is physical pages existing within the zone, which
+	 * is calculated as:
+	 *	present_pages = spanned_pages - absent_pages(pages in holes);
+	 *
+	 * managed_pages is present pages managed by the buddy system, which
+	 * is calculated as (reserved_pages includes pages allocated by the
+	 * bootmem allocator):
+	 *	managed_pages = present_pages - reserved_pages;
+	 *
+	 * So present_pages may be used by memory hotplug or memory power
+	 * management logic to figure out unmanaged pages by checking
+	 * (present_pages - managed_pages). And managed_pages should be used
+	 * by page allocator and vm scanner to calculate all kinds of watermarks
+	 * and thresholds.
+	 *
+	 * Locking rules:
+	 *
+	 * zone_start_pfn and spanned_pages are protected by span_seqlock.
+	 * It is a seqlock because it has to be read outside of zone->lock,
+	 * and it is done in the main allocator path.  But, it is written
+	 * quite infrequently.
+	 *
+	 * The span_seq lock is declared along with zone->lock because it is
+	 * frequently read in proximity to zone->lock.  It's good to
+	 * give them a chance of being in the same cacheline.
+	 *
+	 * Write access to present_pages at runtime should be protected by
+	 * mem_hotplug_begin/end(). Any reader who can't tolerant drift of
+	 * present_pages should get_online_mems() to get a stable value.
+	 *
+	 * Read access to managed_pages should be safe because it's unsigned
+	 * long. Write access to zone->managed_pages and totalram_pages are
+	 * protected by managed_page_count_lock at runtime. Idealy only
+	 * adjust_managed_page_count() should be used instead of directly
+	 * touching zone->managed_pages and totalram_pages.
+	 */
+	unsigned long		managed_pages;
+	unsigned long		spanned_pages;
+	unsigned long		present_pages;
+
+	const char		*name;
+
+	/*
+	 * Number of MIGRATE_RESERVE page block. To maintain for just
+	 * optimization. Protected by zone->lock.
+	 */
+	int			nr_migrate_reserve_block;
+
+#ifdef CONFIG_MEMORY_ISOLATION
+	/*
+	 * Number of isolated pageblock. It is used to solve incorrect
+	 * freepage counting problem due to racy retrieving migratetype
+	 * of pageblock. Protected by zone->lock.
+	 */
+	unsigned long		nr_isolate_pageblock;
+#endif
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+	/* see spanned/present_pages for more description */
+	seqlock_t		span_seqlock;
+#endif
+
+	/*
+	 * wait_table		-- the array holding the hash table
+	 * wait_table_hash_nr_entries	-- the size of the hash table array
+	 * wait_table_bits	-- wait_table_size == (1 << wait_table_bits)
+	 *
+	 * The purpose of all these is to keep track of the people
+	 * waiting for a page to become available and make them
+	 * runnable again when possible. The trouble is that this
+	 * consumes a lot of space, especially when so few things
+	 * wait on pages at a given time. So instead of using
+	 * per-page waitqueues, we use a waitqueue hash table.
+	 *
+	 * The bucket discipline is to sleep on the same queue when
+	 * colliding and wake all in that wait queue when removing.
+	 * When something wakes, it must check to be sure its page is
+	 * truly available, a la thundering herd. The cost of a
+	 * collision is great, but given the expected load of the
+	 * table, they should be so rare as to be outweighed by the
+	 * benefits from the saved space.
+	 *
+	 * __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the
+	 * primary users of these fields, and in mm/page_alloc.c
+	 * free_area_init_core() performs the initialization of them.
+	 */
+	wait_queue_head_t	*wait_table;
+	unsigned long		wait_table_hash_nr_entries;
+	unsigned long		wait_table_bits;
+
+	ZONE_PADDING(_pad1_)
+	/* free areas of different sizes */
+	struct free_area	free_area[MAX_ORDER];
+
+	/* zone flags, see below */
+	unsigned long		flags;
+
+	/* Write-intensive fields used from the page allocator */
+	spinlock_t		lock;
+
+	ZONE_PADDING(_pad2_)
+
+	/* Write-intensive fields used by page reclaim */
+
+	/* Fields commonly accessed by the page reclaim scanner */
+	spinlock_t		lru_lock;
+	struct lruvec		lruvec;
+
+	/* Evictions & activations on the inactive file list */
+	atomic_long_t		inactive_age;
+
+	/*
+	 * When free pages are below this point, additional steps are taken
+	 * when reading the number of free pages to avoid per-cpu counter
+	 * drift allowing watermarks to be breached
+	 */
+	unsigned long percpu_drift_mark;
+
+#if defined CONFIG_COMPACTION || defined CONFIG_CMA
+	/* pfn where compaction free scanner should start */
+	unsigned long		compact_cached_free_pfn;
+	/* pfn where async and sync compaction migration scanner should start */
+	unsigned long		compact_cached_migrate_pfn[2];
+#endif
+
+#ifdef CONFIG_COMPACTION
+	/*
+	 * On compaction failure, 1<<compact_defer_shift compactions
+	 * are skipped before trying again. The number attempted since
+	 * last failure is tracked with compact_considered.
+	 */
+	unsigned int		compact_considered;
+	unsigned int		compact_defer_shift;
+	int			compact_order_failed;
+#endif
+
+#if defined CONFIG_COMPACTION || defined CONFIG_CMA
+	/* Set to true when the PG_migrate_skip bits should be cleared */
+	bool			compact_blockskip_flush;
+#endif
+
+	ZONE_PADDING(_pad3_)
+	/* Zone statistics */
+	atomic_long_t		vm_stat[NR_VM_ZONE_STAT_ITEMS];
+} ____cacheline_internodealigned_in_smp;
+
+enum zone_flags {
+	ZONE_RECLAIM_LOCKED,		/* prevents concurrent reclaim */
+	ZONE_OOM_LOCKED,		/* zone is in OOM killer zonelist */
+	ZONE_CONGESTED,			/* zone has many dirty pages backed by
+					 * a congested BDI
+					 */
+	ZONE_DIRTY,			/* reclaim scanning has recently found
+					 * many dirty file pages at the tail
+					 * of the LRU.
+					 */
+	ZONE_WRITEBACK,			/* reclaim scanning has recently found
+					 * many pages under writeback
+					 */
+	ZONE_FAIR_DEPLETED,		/* fair zone policy batch depleted */
+};
+
+static inline unsigned long zone_end_pfn(const struct zone *zone)
+{
+	return zone->zone_start_pfn + zone->spanned_pages;
+}
+
+static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn)
+{
+	return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone);
+}
+
+static inline bool zone_is_initialized(struct zone *zone)
+{
+	return !!zone->wait_table;
+}
+
+static inline bool zone_is_empty(struct zone *zone)
+{
+	return zone->spanned_pages == 0;
+}
+
+/*
+ * The "priority" of VM scanning is how much of the queues we will scan in one
+ * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
+ * queues ("queue_length >> 12") during an aging round.
+ */
+#define DEF_PRIORITY 12
+
+/* Maximum number of zones on a zonelist */
+#define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES)
+
+#ifdef CONFIG_NUMA
+
+/*
+ * The NUMA zonelists are doubled because we need zonelists that restrict the
+ * allocations to a single node for __GFP_THISNODE.
+ *
+ * [0]	: Zonelist with fallback
+ * [1]	: No fallback (__GFP_THISNODE)
+ */
+#define MAX_ZONELISTS 2
+
+
+/*
+ * We cache key information from each zonelist for smaller cache
+ * footprint when scanning for free pages in get_page_from_freelist().
+ *
+ * 1) The BITMAP fullzones tracks which zones in a zonelist have come
+ *    up short of free memory since the last time (last_fullzone_zap)
+ *    we zero'd fullzones.
+ * 2) The array z_to_n[] maps each zone in the zonelist to its node
+ *    id, so that we can efficiently evaluate whether that node is
+ *    set in the current tasks mems_allowed.
+ *
+ * Both fullzones and z_to_n[] are one-to-one with the zonelist,
+ * indexed by a zones offset in the zonelist zones[] array.
+ *
+ * The get_page_from_freelist() routine does two scans.  During the
+ * first scan, we skip zones whose corresponding bit in 'fullzones'
+ * is set or whose corresponding node in current->mems_allowed (which
+ * comes from cpusets) is not set.  During the second scan, we bypass
+ * this zonelist_cache, to ensure we look methodically at each zone.
+ *
+ * Once per second, we zero out (zap) fullzones, forcing us to
+ * reconsider nodes that might have regained more free memory.
+ * The field last_full_zap is the time we last zapped fullzones.
+ *
+ * This mechanism reduces the amount of time we waste repeatedly
+ * reexaming zones for free memory when they just came up low on
+ * memory momentarilly ago.
+ *
+ * The zonelist_cache struct members logically belong in struct
+ * zonelist.  However, the mempolicy zonelists constructed for
+ * MPOL_BIND are intentionally variable length (and usually much
+ * shorter).  A general purpose mechanism for handling structs with
+ * multiple variable length members is more mechanism than we want
+ * here.  We resort to some special case hackery instead.
+ *
+ * The MPOL_BIND zonelists don't need this zonelist_cache (in good
+ * part because they are shorter), so we put the fixed length stuff
+ * at the front of the zonelist struct, ending in a variable length
+ * zones[], as is needed by MPOL_BIND.
+ *
+ * Then we put the optional zonelist cache on the end of the zonelist
+ * struct.  This optional stuff is found by a 'zlcache_ptr' pointer in
+ * the fixed length portion at the front of the struct.  This pointer
+ * both enables us to find the zonelist cache, and in the case of
+ * MPOL_BIND zonelists, (which will just set the zlcache_ptr to NULL)
+ * to know that the zonelist cache is not there.
+ *
+ * The end result is that struct zonelists come in two flavors:
+ *  1) The full, fixed length version, shown below, and
+ *  2) The custom zonelists for MPOL_BIND.
+ * The custom MPOL_BIND zonelists have a NULL zlcache_ptr and no zlcache.
+ *
+ * Even though there may be multiple CPU cores on a node modifying
+ * fullzones or last_full_zap in the same zonelist_cache at the same
+ * time, we don't lock it.  This is just hint data - if it is wrong now
+ * and then, the allocator will still function, perhaps a bit slower.
+ */
+
+
+struct zonelist_cache {
+	unsigned short z_to_n[MAX_ZONES_PER_ZONELIST];		/* zone->nid */
+	DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST);	/* zone full? */
+	unsigned long last_full_zap;		/* when last zap'd (jiffies) */
+};
+#else
+#define MAX_ZONELISTS 1
+struct zonelist_cache;
+#endif
+
+/*
+ * This struct contains information about a zone in a zonelist. It is stored
+ * here to avoid dereferences into large structures and lookups of tables
+ */
+struct zoneref {
+	struct zone *zone;	/* Pointer to actual zone */
+	int zone_idx;		/* zone_idx(zoneref->zone) */
+};
+
+/*
+ * One allocation request operates on a zonelist. A zonelist
+ * is a list of zones, the first one is the 'goal' of the
+ * allocation, the other zones are fallback zones, in decreasing
+ * priority.
+ *
+ * If zlcache_ptr is not NULL, then it is just the address of zlcache,
+ * as explained above.  If zlcache_ptr is NULL, there is no zlcache.
+ * *
+ * To speed the reading of the zonelist, the zonerefs contain the zone index
+ * of the entry being read. Helper functions to access information given
+ * a struct zoneref are
+ *
+ * zonelist_zone()	- Return the struct zone * for an entry in _zonerefs
+ * zonelist_zone_idx()	- Return the index of the zone for an entry
+ * zonelist_node_idx()	- Return the index of the node for an entry
+ */
+struct zonelist {
+	struct zonelist_cache *zlcache_ptr;		     // NULL or &zlcache
+	struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];
+#ifdef CONFIG_NUMA
+	struct zonelist_cache zlcache;			     // optional ...
+#endif
+};
+
+#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
+struct node_active_region {
+	unsigned long start_pfn;
+	unsigned long end_pfn;
+	int nid;
+};
+#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
+
+#ifndef CONFIG_DISCONTIGMEM
+/* The array of struct pages - for discontigmem use pgdat->lmem_map */
+extern struct page *mem_map;
+#endif
+
+/*
+ * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM
+ * (mostly NUMA machines?) to denote a higher-level memory zone than the
+ * zone denotes.
+ *
+ * On NUMA machines, each NUMA node would have a pg_data_t to describe
+ * it's memory layout.
+ *
+ * Memory statistics and page replacement data structures are maintained on a
+ * per-zone basis.
+ */
+struct bootmem_data;
+typedef struct pglist_data {
+	struct zone node_zones[MAX_NR_ZONES];
+	struct zonelist node_zonelists[MAX_ZONELISTS];
+	int nr_zones;
+#ifdef CONFIG_FLAT_NODE_MEM_MAP	/* means !SPARSEMEM */
+	struct page *node_mem_map;
+#ifdef CONFIG_PAGE_EXTENSION
+	struct page_ext *node_page_ext;
+#endif
+#endif
+#ifndef CONFIG_NO_BOOTMEM
+	struct bootmem_data *bdata;
+#endif
+#ifdef CONFIG_MEMORY_HOTPLUG
+	/*
+	 * Must be held any time you expect node_start_pfn, node_present_pages
+	 * or node_spanned_pages stay constant.  Holding this will also
+	 * guarantee that any pfn_valid() stays that way.
+	 *
+	 * pgdat_resize_lock() and pgdat_resize_unlock() are provided to
+	 * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG.
+	 *
+	 * Nests above zone->lock and zone->span_seqlock
+	 */
+	spinlock_t node_size_lock;
+#endif
+	unsigned long node_start_pfn;
+	unsigned long node_present_pages; /* total number of physical pages */
+	unsigned long node_spanned_pages; /* total size of physical page
+					     range, including holes */
+	int node_id;
+	wait_queue_head_t kswapd_wait;
+	wait_queue_head_t pfmemalloc_wait;
+	struct task_struct *kswapd;	/* Protected by
+					   mem_hotplug_begin/end() */
+	int kswapd_max_order;
+	enum zone_type classzone_idx;
+#ifdef CONFIG_NUMA_BALANCING
+	/* Lock serializing the migrate rate limiting window */
+	spinlock_t numabalancing_migrate_lock;
+
+	/* Rate limiting time interval */
+	unsigned long numabalancing_migrate_next_window;
+
+	/* Number of pages migrated during the rate limiting time interval */
+	unsigned long numabalancing_migrate_nr_pages;
+#endif
+} pg_data_t;
+
+#define node_present_pages(nid)	(NODE_DATA(nid)->node_present_pages)
+#define node_spanned_pages(nid)	(NODE_DATA(nid)->node_spanned_pages)
+#ifdef CONFIG_FLAT_NODE_MEM_MAP
+#define pgdat_page_nr(pgdat, pagenr)	((pgdat)->node_mem_map + (pagenr))
+#else
+#define pgdat_page_nr(pgdat, pagenr)	pfn_to_page((pgdat)->node_start_pfn + (pagenr))
+#endif
+#define nid_page_nr(nid, pagenr) 	pgdat_page_nr(NODE_DATA(nid),(pagenr))
+
+#define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
+#define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid))
+
+static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
+{
+	return pgdat->node_start_pfn + pgdat->node_spanned_pages;
+}
+
+static inline bool pgdat_is_empty(pg_data_t *pgdat)
+{
+	return !pgdat->node_start_pfn && !pgdat->node_spanned_pages;
+}
+
+#include <linux/memory_hotplug.h>
+
+extern struct mutex zonelists_mutex;
+void build_all_zonelists(pg_data_t *pgdat, struct zone *zone);
+void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx);
+bool zone_watermark_ok(struct zone *z, unsigned int order,
+		unsigned long mark, int classzone_idx, int alloc_flags);
+bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
+		unsigned long mark, int classzone_idx, int alloc_flags);
+enum memmap_context {
+	MEMMAP_EARLY,
+	MEMMAP_HOTPLUG,
+};
+extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
+				     unsigned long size,
+				     enum memmap_context context);
+
+extern void lruvec_init(struct lruvec *lruvec);
+
+static inline struct zone *lruvec_zone(struct lruvec *lruvec)
+{
+#ifdef CONFIG_MEMCG
+	return lruvec->zone;
+#else
+	return container_of(lruvec, struct zone, lruvec);
+#endif
+}
+
+#ifdef CONFIG_HAVE_MEMORY_PRESENT
+void memory_present(int nid, unsigned long start, unsigned long end);
+#else
+static inline void memory_present(int nid, unsigned long start, unsigned long end) {}
+#endif
+
+#ifdef CONFIG_HAVE_MEMORYLESS_NODES
+int local_memory_node(int node_id);
+#else
+static inline int local_memory_node(int node_id) { return node_id; };
+#endif
+
+#ifdef CONFIG_NEED_NODE_MEMMAP_SIZE
+unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
+#endif
+
+/*
+ * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
+ */
+#define zone_idx(zone)		((zone) - (zone)->zone_pgdat->node_zones)
+
+static inline int populated_zone(struct zone *zone)
+{
+	return (!!zone->present_pages);
+}
+
+extern int movable_zone;
+
+#ifdef CONFIG_HIGHMEM
+static inline int zone_movable_is_highmem(void)
+{
+#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
+	return movable_zone == ZONE_HIGHMEM;
+#else
+	return (ZONE_MOVABLE - 1) == ZONE_HIGHMEM;
+#endif
+}
+#endif
+
+static inline int is_highmem_idx(enum zone_type idx)
+{
+#ifdef CONFIG_HIGHMEM
+	return (idx == ZONE_HIGHMEM ||
+		(idx == ZONE_MOVABLE && zone_movable_is_highmem()));
+#else
+	return 0;
+#endif
+}
+
+/**
+ * is_highmem - helper function to quickly check if a struct zone is a 
+ *              highmem zone or not.  This is an attempt to keep references
+ *              to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
+ * @zone - pointer to struct zone variable
+ */
+static inline int is_highmem(struct zone *zone)
+{
+#ifdef CONFIG_HIGHMEM
+	int zone_off = (char *)zone - (char *)zone->zone_pgdat->node_zones;
+	return zone_off == ZONE_HIGHMEM * sizeof(*zone) ||
+	       (zone_off == ZONE_MOVABLE * sizeof(*zone) &&
+		zone_movable_is_highmem());
+#else
+	return 0;
+#endif
+}
+
+/* These two functions are used to setup the per zone pages min values */
+struct ctl_table;
+int min_free_kbytes_sysctl_handler(struct ctl_table *, int,
+					void __user *, size_t *, loff_t *);
+extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1];
+int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int,
+					void __user *, size_t *, loff_t *);
+int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int,
+					void __user *, size_t *, loff_t *);
+int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
+			void __user *, size_t *, loff_t *);
+int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
+			void __user *, size_t *, loff_t *);
+
+extern int numa_zonelist_order_handler(struct ctl_table *, int,
+			void __user *, size_t *, loff_t *);
+extern char numa_zonelist_order[];
+#define NUMA_ZONELIST_ORDER_LEN 16	/* string buffer size */
+
+#ifndef CONFIG_NEED_MULTIPLE_NODES
+
+extern struct pglist_data contig_page_data;
+#define NODE_DATA(nid)		(&contig_page_data)
+#define NODE_MEM_MAP(nid)	mem_map
+
+#else /* CONFIG_NEED_MULTIPLE_NODES */
+
+#include <asm/mmzone.h>
+
+#endif /* !CONFIG_NEED_MULTIPLE_NODES */
+
+extern struct pglist_data *first_online_pgdat(void);
+extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
+extern struct zone *next_zone(struct zone *zone);
+
+/**
+ * for_each_online_pgdat - helper macro to iterate over all online nodes
+ * @pgdat - pointer to a pg_data_t variable
+ */
+#define for_each_online_pgdat(pgdat)			\
+	for (pgdat = first_online_pgdat();		\
+	     pgdat;					\
+	     pgdat = next_online_pgdat(pgdat))
+/**
+ * for_each_zone - helper macro to iterate over all memory zones
+ * @zone - pointer to struct zone variable
+ *
+ * The user only needs to declare the zone variable, for_each_zone
+ * fills it in.
+ */
+#define for_each_zone(zone)			        \
+	for (zone = (first_online_pgdat())->node_zones; \
+	     zone;					\
+	     zone = next_zone(zone))
+
+#define for_each_populated_zone(zone)		        \
+	for (zone = (first_online_pgdat())->node_zones; \
+	     zone;					\
+	     zone = next_zone(zone))			\
+		if (!populated_zone(zone))		\
+			; /* do nothing */		\
+		else
+
+static inline struct zone *zonelist_zone(struct zoneref *zoneref)
+{
+	return zoneref->zone;
+}
+
+static inline int zonelist_zone_idx(struct zoneref *zoneref)
+{
+	return zoneref->zone_idx;
+}
+
+static inline int zonelist_node_idx(struct zoneref *zoneref)
+{
+#ifdef CONFIG_NUMA
+	/* zone_to_nid not available in this context */
+	return zoneref->zone->node;
+#else
+	return 0;
+#endif /* CONFIG_NUMA */
+}
+
+/**
+ * next_zones_zonelist - Returns the next zone at or below highest_zoneidx within the allowed nodemask using a cursor within a zonelist as a starting point
+ * @z - The cursor used as a starting point for the search
+ * @highest_zoneidx - The zone index of the highest zone to return
+ * @nodes - An optional nodemask to filter the zonelist with
+ *
+ * This function returns the next zone at or below a given zone index that is
+ * within the allowed nodemask using a cursor as the starting point for the
+ * search. The zoneref returned is a cursor that represents the current zone
+ * being examined. It should be advanced by one before calling
+ * next_zones_zonelist again.
+ */
+struct zoneref *next_zones_zonelist(struct zoneref *z,
+					enum zone_type highest_zoneidx,
+					nodemask_t *nodes);
+
+/**
+ * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
+ * @zonelist - The zonelist to search for a suitable zone
+ * @highest_zoneidx - The zone index of the highest zone to return
+ * @nodes - An optional nodemask to filter the zonelist with
+ * @zone - The first suitable zone found is returned via this parameter
+ *
+ * This function returns the first zone at or below a given zone index that is
+ * within the allowed nodemask. The zoneref returned is a cursor that can be
+ * used to iterate the zonelist with next_zones_zonelist by advancing it by
+ * one before calling.
+ */
+static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
+					enum zone_type highest_zoneidx,
+					nodemask_t *nodes,
+					struct zone **zone)
+{
+	struct zoneref *z = next_zones_zonelist(zonelist->_zonerefs,
+							highest_zoneidx, nodes);
+	*zone = zonelist_zone(z);
+	return z;
+}
+
+/**
+ * for_each_zone_zonelist_nodemask - helper macro to iterate over valid zones in a zonelist at or below a given zone index and within a nodemask
+ * @zone - The current zone in the iterator
+ * @z - The current pointer within zonelist->zones being iterated
+ * @zlist - The zonelist being iterated
+ * @highidx - The zone index of the highest zone to return
+ * @nodemask - Nodemask allowed by the allocator
+ *
+ * This iterator iterates though all zones at or below a given zone index and
+ * within a given nodemask
+ */
+#define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
+	for (z = first_zones_zonelist(zlist, highidx, nodemask, &zone);	\
+		zone;							\
+		z = next_zones_zonelist(++z, highidx, nodemask),	\
+			zone = zonelist_zone(z))			\
+
+/**
+ * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
+ * @zone - The current zone in the iterator
+ * @z - The current pointer within zonelist->zones being iterated
+ * @zlist - The zonelist being iterated
+ * @highidx - The zone index of the highest zone to return
+ *
+ * This iterator iterates though all zones at or below a given zone index.
+ */
+#define for_each_zone_zonelist(zone, z, zlist, highidx) \
+	for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
+
+#ifdef CONFIG_SPARSEMEM
+#include <asm/sparsemem.h>
+#endif
+
+#if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \
+	!defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
+static inline unsigned long early_pfn_to_nid(unsigned long pfn)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_FLATMEM
+#define pfn_to_nid(pfn)		(0)
+#endif
+
+#ifdef CONFIG_SPARSEMEM
+
+/*
+ * SECTION_SHIFT    		#bits space required to store a section #
+ *
+ * PA_SECTION_SHIFT		physical address to/from section number
+ * PFN_SECTION_SHIFT		pfn to/from section number
+ */
+#define PA_SECTION_SHIFT	(SECTION_SIZE_BITS)
+#define PFN_SECTION_SHIFT	(SECTION_SIZE_BITS - PAGE_SHIFT)
+
+#define NR_MEM_SECTIONS		(1UL << SECTIONS_SHIFT)
+
+#define PAGES_PER_SECTION       (1UL << PFN_SECTION_SHIFT)
+#define PAGE_SECTION_MASK	(~(PAGES_PER_SECTION-1))
+
+#define SECTION_BLOCKFLAGS_BITS \
+	((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
+
+#if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
+#error Allocator MAX_ORDER exceeds SECTION_SIZE
+#endif
+
+#define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
+#define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
+
+#define SECTION_ALIGN_UP(pfn)	(((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK)
+#define SECTION_ALIGN_DOWN(pfn)	((pfn) & PAGE_SECTION_MASK)
+
+struct page;
+struct page_ext;
+struct mem_section {
+	/*
+	 * This is, logically, a pointer to an array of struct
+	 * pages.  However, it is stored with some other magic.
+	 * (see sparse.c::sparse_init_one_section())
+	 *
+	 * Additionally during early boot we encode node id of
+	 * the location of the section here to guide allocation.
+	 * (see sparse.c::memory_present())
+	 *
+	 * Making it a UL at least makes someone do a cast
+	 * before using it wrong.
+	 */
+	unsigned long section_mem_map;
+
+	/* See declaration of similar field in struct zone */
+	unsigned long *pageblock_flags;
+#ifdef CONFIG_PAGE_EXTENSION
+	/*
+	 * If !SPARSEMEM, pgdat doesn't have page_ext pointer. We use
+	 * section. (see page_ext.h about this.)
+	 */
+	struct page_ext *page_ext;
+	unsigned long pad;
+#endif
+	/*
+	 * WARNING: mem_section must be a power-of-2 in size for the
+	 * calculation and use of SECTION_ROOT_MASK to make sense.
+	 */
+};
+
+#ifdef CONFIG_SPARSEMEM_EXTREME
+#define SECTIONS_PER_ROOT       (PAGE_SIZE / sizeof (struct mem_section))
+#else
+#define SECTIONS_PER_ROOT	1
+#endif
+
+#define SECTION_NR_TO_ROOT(sec)	((sec) / SECTIONS_PER_ROOT)
+#define NR_SECTION_ROOTS	DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
+#define SECTION_ROOT_MASK	(SECTIONS_PER_ROOT - 1)
+
+#ifdef CONFIG_SPARSEMEM_EXTREME
+extern struct mem_section *mem_section[NR_SECTION_ROOTS];
+#else
+extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
+#endif
+
+static inline struct mem_section *__nr_to_section(unsigned long nr)
+{
+	if (!mem_section[SECTION_NR_TO_ROOT(nr)])
+		return NULL;
+	return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
+}
+extern int __section_nr(struct mem_section* ms);
+extern unsigned long usemap_size(void);
+
+/*
+ * We use the lower bits of the mem_map pointer to store
+ * a little bit of information.  There should be at least
+ * 3 bits here due to 32-bit alignment.
+ */
+#define	SECTION_MARKED_PRESENT	(1UL<<0)
+#define SECTION_HAS_MEM_MAP	(1UL<<1)
+#define SECTION_MAP_LAST_BIT	(1UL<<2)
+#define SECTION_MAP_MASK	(~(SECTION_MAP_LAST_BIT-1))
+#define SECTION_NID_SHIFT	2
+
+static inline struct page *__section_mem_map_addr(struct mem_section *section)
+{
+	unsigned long map = section->section_mem_map;
+	map &= SECTION_MAP_MASK;
+	return (struct page *)map;
+}
+
+static inline int present_section(struct mem_section *section)
+{
+	return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
+}
+
+static inline int present_section_nr(unsigned long nr)
+{
+	return present_section(__nr_to_section(nr));
+}
+
+static inline int valid_section(struct mem_section *section)
+{
+	return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
+}
+
+static inline int valid_section_nr(unsigned long nr)
+{
+	return valid_section(__nr_to_section(nr));
+}
+
+static inline struct mem_section *__pfn_to_section(unsigned long pfn)
+{
+	return __nr_to_section(pfn_to_section_nr(pfn));
+}
+
+#ifndef CONFIG_HAVE_ARCH_PFN_VALID
+static inline int pfn_valid(unsigned long pfn)
+{
+	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
+		return 0;
+	return valid_section(__nr_to_section(pfn_to_section_nr(pfn)));
+}
+#endif
+
+static inline int pfn_present(unsigned long pfn)
+{
+	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
+		return 0;
+	return present_section(__nr_to_section(pfn_to_section_nr(pfn)));
+}
+
+/*
+ * These are _only_ used during initialisation, therefore they
+ * can use __initdata ...  They could have names to indicate
+ * this restriction.
+ */
+#ifdef CONFIG_NUMA
+#define pfn_to_nid(pfn)							\
+({									\
+	unsigned long __pfn_to_nid_pfn = (pfn);				\
+	page_to_nid(pfn_to_page(__pfn_to_nid_pfn));			\
+})
+#else
+#define pfn_to_nid(pfn)		(0)
+#endif
+
+#define early_pfn_valid(pfn)	pfn_valid(pfn)
+void sparse_init(void);
+#else
+#define sparse_init()	do {} while (0)
+#define sparse_index_init(_sec, _nid)  do {} while (0)
+#endif /* CONFIG_SPARSEMEM */
+
+#ifdef CONFIG_NODES_SPAN_OTHER_NODES
+bool early_pfn_in_nid(unsigned long pfn, int nid);
+#else
+#define early_pfn_in_nid(pfn, nid)	(1)
+#endif
+
+#ifndef early_pfn_valid
+#define early_pfn_valid(pfn)	(1)
+#endif
+
+void memory_present(int nid, unsigned long start, unsigned long end);
+unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
+
+/*
+ * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we
+ * need to check pfn validility within that MAX_ORDER_NR_PAGES block.
+ * pfn_valid_within() should be used in this case; we optimise this away
+ * when we have no holes within a MAX_ORDER_NR_PAGES block.
+ */
+#ifdef CONFIG_HOLES_IN_ZONE
+#define pfn_valid_within(pfn) pfn_valid(pfn)
+#else
+#define pfn_valid_within(pfn) (1)
+#endif
+
+#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
+/*
+ * pfn_valid() is meant to be able to tell if a given PFN has valid memmap
+ * associated with it or not. In FLATMEM, it is expected that holes always
+ * have valid memmap as long as there is valid PFNs either side of the hole.
+ * In SPARSEMEM, it is assumed that a valid section has a memmap for the
+ * entire section.
+ *
+ * However, an ARM, and maybe other embedded architectures in the future
+ * free memmap backing holes to save memory on the assumption the memmap is
+ * never used. The page_zone linkages are then broken even though pfn_valid()
+ * returns true. A walker of the full memmap must then do this additional
+ * check to ensure the memmap they are looking at is sane by making sure
+ * the zone and PFN linkages are still valid. This is expensive, but walkers
+ * of the full memmap are extremely rare.
+ */
+int memmap_valid_within(unsigned long pfn,
+					struct page *page, struct zone *zone);
+#else
+static inline int memmap_valid_within(unsigned long pfn,
+					struct page *page, struct zone *zone)
+{
+	return 1;
+}
+#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
+
+#endif /* !__GENERATING_BOUNDS.H */
+#endif /* !__ASSEMBLY__ */
+#endif /* _LINUX_MMZONE_H */