Initial commit: OpenHarmony-v4.0-ReleaseOpenHarmony-v4.0-Release

1 files changed, 9069 insertions, 0 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
new file mode 100644
index 000000000..468e20610
--- /dev/null
+++ b/mm/page_alloc.c
@@ -0,0 +1,9069 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  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/highmem.h>
+#include <linux/swap.h>
+#include <linux/interrupt.h>
+#include <linux/pagemap.h>
+#include <linux/jiffies.h>
+#include <linux/memblock.h>
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/kasan.h>
+#include <linux/module.h>
+#include <linux/suspend.h>
+#include <linux/pagevec.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/ratelimit.h>
+#include <linux/oom.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/vmstat.h>
+#include <linux/mempolicy.h>
+#include <linux/memremap.h>
+#include <linux/stop_machine.h>
+#include <linux/random.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/debugobjects.h>
+#include <linux/kmemleak.h>
+#include <linux/compaction.h>
+#include <trace/events/kmem.h>
+#include <trace/events/oom.h>
+#include <linux/prefetch.h>
+#include <linux/mm_inline.h>
+#include <linux/migrate.h>
+#include <linux/hugetlb.h>
+#include <linux/sched/rt.h>
+#include <linux/sched/mm.h>
+#include <linux/page_owner.h>
+#include <linux/kthread.h>
+#include <linux/memcontrol.h>
+#include <linux/ftrace.h>
+#include <linux/lockdep.h>
+#include <linux/nmi.h>
+#include <linux/psi.h>
+#include <linux/padata.h>
+#include <linux/khugepaged.h>
+#include <linux/zswapd.h>
+#ifdef CONFIG_RECLAIM_ACCT
+#include <linux/reclaim_acct.h>
+#endif
+
+#include <asm/sections.h>
+#include <asm/tlbflush.h>
+#include <asm/div64.h>
+#include "internal.h"
+#include "shuffle.h"
+#include "page_reporting.h"
+
+/* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */
+typedef int __bitwise fpi_t;
+
+/* No special request */
+#define FPI_NONE                ((__force fpi_t)0)
+
+/*
+ * Skip free page reporting notification for the (possibly merged) page.
+ * This does not hinder free page reporting from grabbing the page,
+ * reporting it and marking it "reported" -  it only skips notifying
+ * the free page reporting infrastructure about a newly freed page. For
+ * example, used when temporarily pulling a page from a freelist and
+ * putting it back unmodified.
+ */
+#define FPI_SKIP_REPORT_NOTIFY  ((__force fpi_t)BIT(0))
+
+/*
+ * Place the (possibly merged) page to the tail of the freelist. Will ignore
+ * page shuffling (relevant code - e.g., memory onlining - is expected to
+ * shuffle the whole zone).
+ *
+ * Note: No code should rely on this flag for correctness - it's purely
+ *       to allow for optimizations when handing back either fresh pages
+ *       (memory onlining) or untouched pages (page isolation, free page
+ *       reporting).
+ */
+#define FPI_TO_TAIL             ((__force fpi_t)BIT(1))
+
+/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
+static DEFINE_MUTEX(pcp_batch_high_lock);
+#define MIN_PERCPU_PAGELIST_FRACTION    (8)
+
+#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
+DEFINE_PER_CPU(int, numa_node);
+EXPORT_PER_CPU_SYMBOL(numa_node);
+#endif
+
+DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key);
+
+#ifdef CONFIG_HAVE_MEMORYLESS_NODES
+/*
+ * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
+ * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
+ * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
+ * defined in <linux/topology.h>.
+ */
+DEFINE_PER_CPU(int, _numa_mem_);                /* Kernel "local memory" node */
+EXPORT_PER_CPU_SYMBOL(_numa_mem_);
+#endif
+
+/* work_structs for global per-cpu drains */
+struct pcpu_drain {
+        struct zone *zone;
+        struct work_struct work;
+};
+static DEFINE_MUTEX(pcpu_drain_mutex);
+static DEFINE_PER_CPU(struct pcpu_drain, pcpu_drain);
+
+#ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
+volatile unsigned long latent_entropy __latent_entropy;
+EXPORT_SYMBOL(latent_entropy);
+#endif
+
+/*
+ * 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_MEMORY] = { { [0] = 1UL } },
+        [N_CPU] = { { [0] = 1UL } },
+#endif  /* NUMA */
+};
+EXPORT_SYMBOL(node_states);
+
+atomic_long_t _totalram_pages __read_mostly;
+EXPORT_SYMBOL(_totalram_pages);
+unsigned long totalreserve_pages __read_mostly;
+unsigned long totalcma_pages __read_mostly;
+
+int percpu_pagelist_fraction;
+gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
+#ifdef CONFIG_INIT_ON_ALLOC_DEFAULT_ON
+DEFINE_STATIC_KEY_TRUE(init_on_alloc);
+#else
+DEFINE_STATIC_KEY_FALSE(init_on_alloc);
+#endif
+EXPORT_SYMBOL(init_on_alloc);
+
+#ifdef CONFIG_INIT_ON_FREE_DEFAULT_ON
+DEFINE_STATIC_KEY_TRUE(init_on_free);
+#else
+DEFINE_STATIC_KEY_FALSE(init_on_free);
+#endif
+EXPORT_SYMBOL(init_on_free);
+
+static int __init early_init_on_alloc(char *buf)
+{
+        int ret;
+        bool bool_result;
+
+        ret = kstrtobool(buf, &bool_result);
+        if (ret)
+                return ret;
+        if (bool_result && page_poisoning_enabled())
+                pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_alloc\n");
+        if (bool_result)
+                static_branch_enable(&init_on_alloc);
+        else
+                static_branch_disable(&init_on_alloc);
+        return 0;
+}
+early_param("init_on_alloc", early_init_on_alloc);
+
+static int __init early_init_on_free(char *buf)
+{
+        int ret;
+        bool bool_result;
+
+        ret = kstrtobool(buf, &bool_result);
+        if (ret)
+                return ret;
+        if (bool_result && page_poisoning_enabled())
+                pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_free\n");
+        if (bool_result)
+                static_branch_enable(&init_on_free);
+        else
+                static_branch_disable(&init_on_free);
+        return 0;
+}
+early_param("init_on_free", early_init_on_free);
+
+/*
+ * A cached value of the page's pageblock's migratetype, used when the page is
+ * put on a pcplist. Used to avoid the pageblock migratetype lookup when
+ * freeing from pcplists in most cases, at the cost of possibly becoming stale.
+ * Also the migratetype set in the page does not necessarily match the pcplist
+ * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
+ * other index - this ensures that it will be put on the correct CMA freelist.
+ */
+static inline int get_pcppage_migratetype(struct page *page)
+{
+        return page->index;
+}
+
+static inline void set_pcppage_migratetype(struct page *page, int migratetype)
+{
+        page->index = migratetype;
+}
+
+#ifdef CONFIG_PM_SLEEP
+/*
+ * The following functions are used by the suspend/hibernate code to temporarily
+ * change gfp_allowed_mask in order to avoid using I/O during memory allocations
+ * while devices are suspended.  To avoid races with the suspend/hibernate code,
+ * they should always be called with system_transition_mutex held
+ * (gfp_allowed_mask also should only be modified with system_transition_mutex
+ * held, unless the suspend/hibernate code is guaranteed not to run in parallel
+ * with that modification).
+ */
+
+static gfp_t saved_gfp_mask;
+
+void pm_restore_gfp_mask(void)
+{
+        WARN_ON(!mutex_is_locked(&system_transition_mutex));
+        if (saved_gfp_mask) {
+                gfp_allowed_mask = saved_gfp_mask;
+                saved_gfp_mask = 0;
+        }
+}
+
+void pm_restrict_gfp_mask(void)
+{
+        WARN_ON(!mutex_is_locked(&system_transition_mutex));
+        WARN_ON(saved_gfp_mask);
+        saved_gfp_mask = gfp_allowed_mask;
+        gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
+}
+
+bool pm_suspended_storage(void)
+{
+        if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS))
+                return false;
+        return true;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
+unsigned int pageblock_order __read_mostly;
+#endif
+
+static void __free_pages_ok(struct page *page, unsigned int order,
+                            fpi_t fpi_flags);
+
+/*
+ * 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 leave (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] = {
+#ifdef CONFIG_ZONE_DMA
+        [ZONE_DMA] = 256,
+#endif
+#ifdef CONFIG_ZONE_DMA32
+        [ZONE_DMA32] = 256,
+#endif
+        [ZONE_NORMAL] = 32,
+#ifdef CONFIG_HIGHMEM
+        [ZONE_HIGHMEM] = 0,
+#endif
+        [ZONE_MOVABLE] = 0,
+};
+
+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",
+#ifdef CONFIG_ZONE_DEVICE
+         "Device",
+#endif
+};
+
+const char * const migratetype_names[MIGRATE_TYPES] = {
+        "Unmovable",
+        "Movable",
+        "Reclaimable",
+#ifdef CONFIG_CMA_REUSE
+        "CMA",
+#endif
+        "HighAtomic",
+#if defined(CONFIG_CMA) && !defined(CONFIG_CMA_REUSE)
+        "CMA",
+#endif
+#ifdef CONFIG_MEMORY_ISOLATION
+        "Isolate",
+#endif
+};
+
+compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = {
+        [NULL_COMPOUND_DTOR] = NULL,
+        [COMPOUND_PAGE_DTOR] = free_compound_page,
+#ifdef CONFIG_HUGETLB_PAGE
+        [HUGETLB_PAGE_DTOR] = free_huge_page,
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+        [TRANSHUGE_PAGE_DTOR] = free_transhuge_page,
+#endif
+};
+
+int min_free_kbytes = 1024;
+int user_min_free_kbytes = -1;
+#ifdef CONFIG_DISCONTIGMEM
+/*
+ * DiscontigMem defines memory ranges as separate pg_data_t even if the ranges
+ * are not on separate NUMA nodes. Functionally this works but with
+ * watermark_boost_factor, it can reclaim prematurely as the ranges can be
+ * quite small. By default, do not boost watermarks on discontigmem as in
+ * many cases very high-order allocations like THP are likely to be
+ * unsupported and the premature reclaim offsets the advantage of long-term
+ * fragmentation avoidance.
+ */
+int watermark_boost_factor __read_mostly;
+#else
+int watermark_boost_factor __read_mostly = 15000;
+#endif
+int watermark_scale_factor = 10;
+
+static unsigned long nr_kernel_pages __initdata;
+static unsigned long nr_all_pages __initdata;
+static unsigned long dma_reserve __initdata;
+
+static unsigned long arch_zone_lowest_possible_pfn[MAX_NR_ZONES] __initdata;
+static unsigned long arch_zone_highest_possible_pfn[MAX_NR_ZONES] __initdata;
+static unsigned long required_kernelcore __initdata;
+static unsigned long required_kernelcore_percent __initdata;
+static unsigned long required_movablecore __initdata;
+static unsigned long required_movablecore_percent __initdata;
+static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
+static bool mirrored_kernelcore __meminitdata;
+
+/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
+int movable_zone;
+EXPORT_SYMBOL(movable_zone);
+
+#if MAX_NUMNODES > 1
+unsigned int nr_node_ids __read_mostly = MAX_NUMNODES;
+unsigned 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;
+
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+/*
+ * During boot we initialize deferred pages on-demand, as needed, but once
+ * page_alloc_init_late() has finished, the deferred pages are all initialized,
+ * and we can permanently disable that path.
+ */
+static DEFINE_STATIC_KEY_TRUE(deferred_pages);
+
+/*
+ * Calling kasan_free_pages() only after deferred memory initialization
+ * has completed. Poisoning pages during deferred memory init will greatly
+ * lengthen the process and cause problem in large memory systems as the
+ * deferred pages initialization is done with interrupt disabled.
+ *
+ * Assuming that there will be no reference to those newly initialized
+ * pages before they are ever allocated, this should have no effect on
+ * KASAN memory tracking as the poison will be properly inserted at page
+ * allocation time. The only corner case is when pages are allocated by
+ * on-demand allocation and then freed again before the deferred pages
+ * initialization is done, but this is not likely to happen.
+ */
+static inline void kasan_free_nondeferred_pages(struct page *page, int order)
+{
+        if (!static_branch_unlikely(&deferred_pages))
+                kasan_free_pages(page, order);
+}
+
+/* Returns true if the struct page for the pfn is uninitialised */
+static inline bool __meminit early_page_uninitialised(unsigned long pfn)
+{
+        int nid = early_pfn_to_nid(pfn);
+
+        if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn)
+                return true;
+
+        return false;
+}
+
+/*
+ * Returns true when the remaining initialisation should be deferred until
+ * later in the boot cycle when it can be parallelised.
+ */
+static bool __meminit
+defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
+{
+        static unsigned long prev_end_pfn, nr_initialised;
+
+        /*
+         * prev_end_pfn static that contains the end of previous zone
+         * No need to protect because called very early in boot before smp_init.
+         */
+        if (prev_end_pfn != end_pfn) {
+                prev_end_pfn = end_pfn;
+                nr_initialised = 0;
+        }
+
+        /* Always populate low zones for address-constrained allocations */
+        if (end_pfn < pgdat_end_pfn(NODE_DATA(nid)))
+                return false;
+
+        if (NODE_DATA(nid)->first_deferred_pfn != ULONG_MAX)
+                return true;
+        /*
+         * We start only with one section of pages, more pages are added as
+         * needed until the rest of deferred pages are initialized.
+         */
+        nr_initialised++;
+        if ((nr_initialised > PAGES_PER_SECTION) &&
+            (pfn & (PAGES_PER_SECTION - 1)) == 0) {
+                NODE_DATA(nid)->first_deferred_pfn = pfn;
+                return true;
+        }
+        return false;
+}
+#else
+#define kasan_free_nondeferred_pages(p, o)      kasan_free_pages(p, o)
+
+static inline bool early_page_uninitialised(unsigned long pfn)
+{
+        return false;
+}
+
+static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
+{
+        return false;
+}
+#endif
+
+/* Return a pointer to the bitmap storing bits affecting a block of pages */
+static inline unsigned long *get_pageblock_bitmap(struct page *page,
+                                                        unsigned long pfn)
+{
+#ifdef CONFIG_SPARSEMEM
+        return section_to_usemap(__pfn_to_section(pfn));
+#else
+        return page_zone(page)->pageblock_flags;
+#endif /* CONFIG_SPARSEMEM */
+}
+
+static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
+{
+#ifdef CONFIG_SPARSEMEM
+        pfn &= (PAGES_PER_SECTION-1);
+#else
+        pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
+#endif /* CONFIG_SPARSEMEM */
+        return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
+}
+
+/**
+ * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
+ * @page: The page within the block of interest
+ * @pfn: The target page frame number
+ * @mask: mask of bits that the caller is interested in
+ *
+ * Return: pageblock_bits flags
+ */
+static __always_inline
+unsigned long __get_pfnblock_flags_mask(struct page *page,
+                                        unsigned long pfn,
+                                        unsigned long mask)
+{
+        unsigned long *bitmap;
+        unsigned long bitidx, word_bitidx;
+        unsigned long word;
+
+        bitmap = get_pageblock_bitmap(page, pfn);
+        bitidx = pfn_to_bitidx(page, pfn);
+        word_bitidx = bitidx / BITS_PER_LONG;
+        bitidx &= (BITS_PER_LONG-1);
+
+        word = bitmap[word_bitidx];
+        return (word >> bitidx) & mask;
+}
+
+unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
+                                        unsigned long mask)
+{
+        return __get_pfnblock_flags_mask(page, pfn, mask);
+}
+
+static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
+{
+        return __get_pfnblock_flags_mask(page, pfn, MIGRATETYPE_MASK);
+}
+
+/**
+ * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
+ * @page: The page within the block of interest
+ * @flags: The flags to set
+ * @pfn: The target page frame number
+ * @mask: mask of bits that the caller is interested in
+ */
+void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
+                                        unsigned long pfn,
+                                        unsigned long mask)
+{
+        unsigned long *bitmap;
+        unsigned long bitidx, word_bitidx;
+        unsigned long old_word, word;
+
+        BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
+        BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits));
+
+        bitmap = get_pageblock_bitmap(page, pfn);
+        bitidx = pfn_to_bitidx(page, pfn);
+        word_bitidx = bitidx / BITS_PER_LONG;
+        bitidx &= (BITS_PER_LONG-1);
+
+        VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
+
+        mask <<= bitidx;
+        flags <<= bitidx;
+
+        word = READ_ONCE(bitmap[word_bitidx]);
+        for (;;) {
+                old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags);
+                if (word == old_word)
+                        break;
+                word = old_word;
+        }
+}
+
+void set_pageblock_migratetype(struct page *page, int migratetype)
+{
+        if (unlikely(page_group_by_mobility_disabled &&
+                     migratetype < MIGRATE_PCPTYPES))
+                migratetype = MIGRATE_UNMOVABLE;
+
+        set_pfnblock_flags_mask(page, (unsigned long)migratetype,
+                                page_to_pfn(page), MIGRATETYPE_MASK);
+}
+
+#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);
+        unsigned long sp, start_pfn;
+
+        do {
+                seq = zone_span_seqbegin(zone);
+                start_pfn = zone->zone_start_pfn;
+                sp = zone->spanned_pages;
+                if (!zone_spans_pfn(zone, pfn))
+                        ret = 1;
+        } while (zone_span_seqretry(zone, seq));
+
+        if (ret)
+                pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
+                        pfn, zone_to_nid(zone), zone->name,
+                        start_pfn, start_pfn + sp);
+
+        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 __maybe_unused 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 __maybe_unused bad_range(struct zone *zone, struct page *page)
+{
+        return 0;
+}
+#endif
+
+static void bad_page(struct page *page, const char *reason)
+{
+        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) {
+                        pr_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;
+
+        pr_alert("BUG: Bad page state in process %s  pfn:%05lx\n",
+                current->comm, page_to_pfn(page));
+        __dump_page(page, reason);
+        dump_page_owner(page);
+
+        print_modules();
+        dump_stack();
+out:
+        /* Leave bad fields for debug, except PageBuddy could make trouble */
+        page_mapcount_reset(page); /* remove PageBuddy */
+        add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
+}
+
+/*
+ * Higher-order pages are called "compound pages".  They are structured thusly:
+ *
+ * The first PAGE_SIZE page is called the "head page" and have PG_head set.
+ *
+ * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded
+ * in bit 0 of page->compound_head. The rest of bits is pointer to head page.
+ *
+ * The first tail page's ->compound_dtor holds the offset in array of compound
+ * page destructors. See compound_page_dtors.
+ *
+ * The first tail page's ->compound_order holds the order of allocation.
+ * This usage means that zero-order pages may not be compound.
+ */
+
+void free_compound_page(struct page *page)
+{
+        mem_cgroup_uncharge(page);
+        __free_pages_ok(page, compound_order(page), FPI_NONE);
+}
+
+void prep_compound_page(struct page *page, unsigned int order)
+{
+        int i;
+        int nr_pages = 1 << order;
+
+        __SetPageHead(page);
+        for (i = 1; i < nr_pages; i++) {
+                struct page *p = page + i;
+                set_page_count(p, 0);
+                p->mapping = TAIL_MAPPING;
+                set_compound_head(p, page);
+        }
+
+        set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
+        set_compound_order(page, order);
+        atomic_set(compound_mapcount_ptr(page), -1);
+        if (hpage_pincount_available(page))
+                atomic_set(compound_pincount_ptr(page), 0);
+}
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+unsigned int _debug_guardpage_minorder;
+
+bool _debug_pagealloc_enabled_early __read_mostly
+                        = IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
+EXPORT_SYMBOL(_debug_pagealloc_enabled_early);
+DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
+EXPORT_SYMBOL(_debug_pagealloc_enabled);
+
+DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
+
+static int __init early_debug_pagealloc(char *buf)
+{
+        return kstrtobool(buf, &_debug_pagealloc_enabled_early);
+}
+early_param("debug_pagealloc", early_debug_pagealloc);
+
+void init_debug_pagealloc(void)
+{
+        if (!debug_pagealloc_enabled())
+                return;
+
+        static_branch_enable(&_debug_pagealloc_enabled);
+
+        if (!debug_guardpage_minorder())
+                return;
+
+        static_branch_enable(&_debug_guardpage_enabled);
+}
+
+static int __init debug_guardpage_minorder_setup(char *buf)
+{
+        unsigned long res;
+
+        if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
+                pr_err("Bad debug_guardpage_minorder value\n");
+                return 0;
+        }
+        _debug_guardpage_minorder = res;
+        pr_info("Setting debug_guardpage_minorder to %lu\n", res);
+        return 0;
+}
+early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
+
+static inline bool set_page_guard(struct zone *zone, struct page *page,
+                                unsigned int order, int migratetype)
+{
+        if (!debug_guardpage_enabled())
+                return false;
+
+        if (order >= debug_guardpage_minorder())
+                return false;
+
+        __SetPageGuard(page);
+        INIT_LIST_HEAD(&page->lru);
+        set_page_private(page, order);
+        /* Guard pages are not available for any usage */
+        __mod_zone_freepage_state(zone, -(1 << order), migratetype);
+
+        return true;
+}
+
+static inline void clear_page_guard(struct zone *zone, struct page *page,
+                                unsigned int order, int migratetype)
+{
+        if (!debug_guardpage_enabled())
+                return;
+
+        __ClearPageGuard(page);
+
+        set_page_private(page, 0);
+        if (!is_migrate_isolate(migratetype))
+                __mod_zone_freepage_state(zone, (1 << order), migratetype);
+}
+#else
+static inline bool set_page_guard(struct zone *zone, struct page *page,
+                        unsigned int order, int migratetype) { return false; }
+static inline void clear_page_guard(struct zone *zone, struct page *page,
+                                unsigned int order, int migratetype) {}
+#endif
+
+static inline void set_buddy_order(struct page *page, unsigned int order)
+{
+        set_page_private(page, order);
+        __SetPageBuddy(page);
+}
+
+/*
+ * This function checks whether a page is free && is the buddy
+ * we can coalesce a page and its buddy if
+ * (a) the buddy is not in a hole (check before calling!) &&
+ * (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 set PageBuddy.
+ * Setting, clearing, and testing PageBuddy is serialized by zone->lock.
+ *
+ * For recording page's order, we use page_private(page).
+ */
+static inline bool page_is_buddy(struct page *page, struct page *buddy,
+                                                        unsigned int order)
+{
+        if (!page_is_guard(buddy) && !PageBuddy(buddy))
+                return false;
+
+        if (buddy_order(buddy) != order)
+                return false;
+
+        /*
+         * zone check is done late to avoid uselessly calculating
+         * zone/node ids for pages that could never merge.
+         */
+        if (page_zone_id(page) != page_zone_id(buddy))
+                return false;
+
+        VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
+
+        return true;
+}
+
+#ifdef CONFIG_COMPACTION
+static inline struct capture_control *task_capc(struct zone *zone)
+{
+        struct capture_control *capc = current->capture_control;
+
+        return unlikely(capc) &&
+                !(current->flags & PF_KTHREAD) &&
+                !capc->page &&
+                capc->cc->zone == zone ? capc : NULL;
+}
+
+static inline bool
+compaction_capture(struct capture_control *capc, struct page *page,
+                   int order, int migratetype)
+{
+        if (!capc || order != capc->cc->order)
+                return false;
+
+        /* Do not accidentally pollute CMA or isolated regions*/
+        if (is_migrate_cma(migratetype) ||
+            is_migrate_isolate(migratetype))
+                return false;
+
+        /*
+         * Do not let lower order allocations polluate a movable pageblock.
+         * This might let an unmovable request use a reclaimable pageblock
+         * and vice-versa but no more than normal fallback logic which can
+         * have trouble finding a high-order free page.
+         */
+        if (order < pageblock_order && migratetype == MIGRATE_MOVABLE)
+                return false;
+
+        capc->page = page;
+        return true;
+}
+
+#else
+static inline struct capture_control *task_capc(struct zone *zone)
+{
+        return NULL;
+}
+
+static inline bool
+compaction_capture(struct capture_control *capc, struct page *page,
+                   int order, int migratetype)
+{
+        return false;
+}
+#endif /* CONFIG_COMPACTION */
+
+/* Used for pages not on another list */
+static inline void add_to_free_list(struct page *page, struct zone *zone,
+                                    unsigned int order, int migratetype)
+{
+        struct free_area *area = &zone->free_area[order];
+
+        list_add(&page->lru, &area->free_list[migratetype]);
+        area->nr_free++;
+}
+
+/* Used for pages not on another list */
+static inline void add_to_free_list_tail(struct page *page, struct zone *zone,
+                                         unsigned int order, int migratetype)
+{
+        struct free_area *area = &zone->free_area[order];
+
+        list_add_tail(&page->lru, &area->free_list[migratetype]);
+        area->nr_free++;
+}
+
+/*
+ * Used for pages which are on another list. Move the pages to the tail
+ * of the list - so the moved pages won't immediately be considered for
+ * allocation again (e.g., optimization for memory onlining).
+ */
+static inline void move_to_free_list(struct page *page, struct zone *zone,
+                                     unsigned int order, int migratetype)
+{
+        struct free_area *area = &zone->free_area[order];
+
+        list_move_tail(&page->lru, &area->free_list[migratetype]);
+}
+
+static inline void del_page_from_free_list(struct page *page, struct zone *zone,
+                                           unsigned int order)
+{
+        /* clear reported state and update reported page count */
+        if (page_reported(page))
+                __ClearPageReported(page);
+
+        list_del(&page->lru);
+        __ClearPageBuddy(page);
+        set_page_private(page, 0);
+        zone->free_area[order].nr_free--;
+}
+
+/*
+ * If this is not the largest possible page, check if the buddy
+ * of the next-highest order is free. If it is, it's possible
+ * that pages are being freed that will coalesce soon. In case,
+ * that is happening, add the free page to the tail of the list
+ * so it's less likely to be used soon and more likely to be merged
+ * as a higher order page
+ */
+static inline bool
+buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn,
+                   struct page *page, unsigned int order)
+{
+        struct page *higher_page, *higher_buddy;
+        unsigned long combined_pfn;
+
+        if (order >= MAX_ORDER - 2)
+                return false;
+
+        if (!pfn_valid_within(buddy_pfn))
+                return false;
+
+        combined_pfn = buddy_pfn & pfn;
+        higher_page = page + (combined_pfn - pfn);
+        buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1);
+        higher_buddy = higher_page + (buddy_pfn - combined_pfn);
+
+        return pfn_valid_within(buddy_pfn) &&
+               page_is_buddy(higher_page, higher_buddy, order + 1);
+}
+
+/*
+ * 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 PageBuddy.
+ * 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.
+ *
+ * -- nyc
+ */
+
+static inline void __free_one_page(struct page *page,
+                unsigned long pfn,
+                struct zone *zone, unsigned int order,
+                int migratetype, fpi_t fpi_flags)
+{
+        struct capture_control *capc = task_capc(zone);
+        unsigned long buddy_pfn;
+        unsigned long combined_pfn;
+        unsigned int max_order;
+        struct page *buddy;
+        bool to_tail;
+
+        max_order = min_t(unsigned int, MAX_ORDER - 1, pageblock_order);
+
+        VM_BUG_ON(!zone_is_initialized(zone));
+        VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
+
+        VM_BUG_ON(migratetype == -1);
+        if (likely(!is_migrate_isolate(migratetype)))
+                __mod_zone_freepage_state(zone, 1 << order, migratetype);
+
+        VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
+        VM_BUG_ON_PAGE(bad_range(zone, page), page);
+
+continue_merging:
+        while (order < max_order) {
+                if (compaction_capture(capc, page, order, migratetype)) {
+                        __mod_zone_freepage_state(zone, -(1 << order),
+                                                                migratetype);
+                        return;
+                }
+                buddy_pfn = __find_buddy_pfn(pfn, order);
+                buddy = page + (buddy_pfn - pfn);
+
+                if (!pfn_valid_within(buddy_pfn))
+                        goto done_merging;
+                if (!page_is_buddy(page, buddy, order))
+                        goto done_merging;
+                /*
+                 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
+                 * merge with it and move up one order.
+                 */
+                if (page_is_guard(buddy))
+                        clear_page_guard(zone, buddy, order, migratetype);
+                else
+                        del_page_from_free_list(buddy, zone, order);
+                combined_pfn = buddy_pfn & pfn;
+                page = page + (combined_pfn - pfn);
+                pfn = combined_pfn;
+                order++;
+        }
+        if (order < MAX_ORDER - 1) {
+                /* If we are here, it means order is >= pageblock_order.
+                 * We want to prevent merge between freepages on isolate
+                 * pageblock and normal pageblock. Without this, pageblock
+                 * isolation could cause incorrect freepage or CMA accounting.
+                 *
+                 * We don't want to hit this code for the more frequent
+                 * low-order merging.
+                 */
+                if (unlikely(has_isolate_pageblock(zone))) {
+                        int buddy_mt;
+
+                        buddy_pfn = __find_buddy_pfn(pfn, order);
+                        buddy = page + (buddy_pfn - pfn);
+                        buddy_mt = get_pageblock_migratetype(buddy);
+
+                        if (migratetype != buddy_mt
+                                        && (is_migrate_isolate(migratetype) ||
+                                                is_migrate_isolate(buddy_mt)))
+                                goto done_merging;
+                }
+                max_order = order + 1;
+                goto continue_merging;
+        }
+
+done_merging:
+        set_buddy_order(page, order);
+
+        if (fpi_flags & FPI_TO_TAIL)
+                to_tail = true;
+        else if (is_shuffle_order(order))
+                to_tail = shuffle_pick_tail();
+        else
+                to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order);
+
+        if (to_tail)
+                add_to_free_list_tail(page, zone, order, migratetype);
+        else
+                add_to_free_list(page, zone, order, migratetype);
+
+        /* Notify page reporting subsystem of freed page */
+        if (!(fpi_flags & FPI_SKIP_REPORT_NOTIFY))
+                page_reporting_notify_free(order);
+}
+
+/*
+ * A bad page could be due to a number of fields. Instead of multiple branches,
+ * try and check multiple fields with one check. The caller must do a detailed
+ * check if necessary.
+ */
+static inline bool page_expected_state(struct page *page,
+                                        unsigned long check_flags)
+{
+        if (unlikely(atomic_read(&page->_mapcount) != -1))
+                return false;
+
+        if (unlikely((unsigned long)page->mapping |
+                        page_ref_count(page) |
+#ifdef CONFIG_MEMCG
+                        (unsigned long)page->mem_cgroup |
+#endif
+                        (page->flags & check_flags)))
+                return false;
+
+        return true;
+}
+
+static const char *page_bad_reason(struct page *page, unsigned long flags)
+{
+        const char *bad_reason = NULL;
+
+        if (unlikely(atomic_read(&page->_mapcount) != -1))
+                bad_reason = "nonzero mapcount";
+        if (unlikely(page->mapping != NULL))
+                bad_reason = "non-NULL mapping";
+        if (unlikely(page_ref_count(page) != 0))
+                bad_reason = "nonzero _refcount";
+        if (unlikely(page->flags & flags)) {
+                if (flags == PAGE_FLAGS_CHECK_AT_PREP)
+                        bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag(s) set";
+                else
+                        bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
+        }
+#ifdef CONFIG_MEMCG
+        if (unlikely(page->mem_cgroup))
+                bad_reason = "page still charged to cgroup";
+#endif
+        return bad_reason;
+}
+
+static void check_free_page_bad(struct page *page)
+{
+        bad_page(page,
+                 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_FREE));
+}
+
+static inline int check_free_page(struct page *page)
+{
+        if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE)))
+                return 0;
+
+        /* Something has gone sideways, find it */
+        check_free_page_bad(page);
+        return 1;
+}
+
+static int free_tail_pages_check(struct page *head_page, struct page *page)
+{
+        int ret = 1;
+
+        /*
+         * We rely page->lru.next never has bit 0 set, unless the page
+         * is PageTail(). Let's make sure that's true even for poisoned ->lru.
+         */
+        BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1);
+
+        if (!IS_ENABLED(CONFIG_DEBUG_VM)) {
+                ret = 0;
+                goto out;
+        }
+        switch (page - head_page) {
+        case 1:
+                /* the first tail page: ->mapping may be compound_mapcount() */
+                if (unlikely(compound_mapcount(page))) {
+                        bad_page(page, "nonzero compound_mapcount");
+                        goto out;
+                }
+                break;
+        case 2:
+                /*
+                 * the second tail page: ->mapping is
+                 * deferred_list.next -- ignore value.
+                 */
+                break;
+        default:
+                if (page->mapping != TAIL_MAPPING) {
+                        bad_page(page, "corrupted mapping in tail page");
+                        goto out;
+                }
+                break;
+        }
+        if (unlikely(!PageTail(page))) {
+                bad_page(page, "PageTail not set");
+                goto out;
+        }
+        if (unlikely(compound_head(page) != head_page)) {
+                bad_page(page, "compound_head not consistent");
+                goto out;
+        }
+        ret = 0;
+out:
+        page->mapping = NULL;
+        clear_compound_head(page);
+        return ret;
+}
+
+static void kernel_init_free_pages(struct page *page, int numpages)
+{
+        int i;
+
+        /* s390's use of memset() could override KASAN redzones. */
+        kasan_disable_current();
+        for (i = 0; i < numpages; i++)
+                clear_highpage(page + i);
+        kasan_enable_current();
+}
+
+static __always_inline bool free_pages_prepare(struct page *page,
+                                        unsigned int order, bool check_free)
+{
+        int bad = 0;
+
+        VM_BUG_ON_PAGE(PageTail(page), page);
+
+        trace_mm_page_free(page, order);
+
+        if (unlikely(PageHWPoison(page)) && !order) {
+                /*
+                 * Do not let hwpoison pages hit pcplists/buddy
+                 * Untie memcg state and reset page's owner
+                 */
+                if (memcg_kmem_enabled() && PageKmemcg(page))
+                        __memcg_kmem_uncharge_page(page, order);
+                reset_page_owner(page, order);
+                return false;
+        }
+
+        /*
+         * Check tail pages before head page information is cleared to
+         * avoid checking PageCompound for order-0 pages.
+         */
+        if (unlikely(order)) {
+                bool compound = PageCompound(page);
+                int i;
+
+                VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
+
+                if (compound)
+                        ClearPageDoubleMap(page);
+                for (i = 1; i < (1 << order); i++) {
+                        if (compound)
+                                bad += free_tail_pages_check(page, page + i);
+                        if (unlikely(check_free_page(page + i))) {
+                                bad++;
+                                continue;
+                        }
+                        (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
+                }
+        }
+        if (PageMappingFlags(page))
+                page->mapping = NULL;
+        if (memcg_kmem_enabled() && PageKmemcg(page))
+                __memcg_kmem_uncharge_page(page, order);
+        if (check_free)
+                bad += check_free_page(page);
+        if (bad)
+                return false;
+
+        page_cpupid_reset_last(page);
+        page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
+        reset_page_owner(page, order);
+
+        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);
+        }
+        if (want_init_on_free())
+                kernel_init_free_pages(page, 1 << order);
+
+        kernel_poison_pages(page, 1 << order, 0);
+        /*
+         * arch_free_page() can make the page's contents inaccessible.  s390
+         * does this.  So nothing which can access the page's contents should
+         * happen after this.
+         */
+        arch_free_page(page, order);
+
+        if (debug_pagealloc_enabled_static())
+                kernel_map_pages(page, 1 << order, 0);
+
+        kasan_free_nondeferred_pages(page, order);
+
+        return true;
+}
+
+#ifdef CONFIG_DEBUG_VM
+/*
+ * With DEBUG_VM enabled, order-0 pages are checked immediately when being freed
+ * to pcp lists. With debug_pagealloc also enabled, they are also rechecked when
+ * moved from pcp lists to free lists.
+ */
+static bool free_pcp_prepare(struct page *page)
+{
+        return free_pages_prepare(page, 0, true);
+}
+
+static bool bulkfree_pcp_prepare(struct page *page)
+{
+        if (debug_pagealloc_enabled_static())
+                return check_free_page(page);
+        else
+                return false;
+}
+#else
+/*
+ * With DEBUG_VM disabled, order-0 pages being freed are checked only when
+ * moving from pcp lists to free list in order to reduce overhead. With
+ * debug_pagealloc enabled, they are checked also immediately when being freed
+ * to the pcp lists.
+ */
+static bool free_pcp_prepare(struct page *page)
+{
+        if (debug_pagealloc_enabled_static())
+                return free_pages_prepare(page, 0, true);
+        else
+                return free_pages_prepare(page, 0, false);
+}
+
+static bool bulkfree_pcp_prepare(struct page *page)
+{
+        return check_free_page(page);
+}
+#endif /* CONFIG_DEBUG_VM */
+
+static inline void prefetch_buddy(struct page *page)
+{
+        unsigned long pfn = page_to_pfn(page);
+        unsigned long buddy_pfn = __find_buddy_pfn(pfn, 0);
+        struct page *buddy = page + (buddy_pfn - pfn);
+
+        prefetch(buddy);
+}
+
+/*
+ * Frees a number of pages from the PCP lists
+ * 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_pcppages_bulk(struct zone *zone, int count,
+                                        struct per_cpu_pages *pcp)
+{
+        int migratetype = 0;
+        int batch_free = 0;
+        int prefetch_nr = 0;
+        bool isolated_pageblocks;
+        struct page *page, *tmp;
+        LIST_HEAD(head);
+
+        /*
+         * Ensure proper count is passed which otherwise would stuck in the
+         * below while (list_empty(list)) loop.
+         */
+        count = min(pcp->count, count);
+        while (count) {
+                struct list_head *list;
+
+                /*
+                 * Remove pages from lists in a round-robin fashion. A
+                 * batch_free count is maintained that is incremented when an
+                 * empty list is encountered.  This is so more pages are freed
+                 * off fuller lists instead of spinning excessively around empty
+                 * lists
+                 */
+                do {
+                        batch_free++;
+                        if (++migratetype == MIGRATE_PCPTYPES)
+                                migratetype = 0;
+                        list = &pcp->lists[migratetype];
+                } while (list_empty(list));
+
+                /* This is the only non-empty list. Free them all. */
+                if (batch_free == MIGRATE_PCPTYPES)
+                        batch_free = count;
+
+                do {
+                        page = list_last_entry(list, struct page, lru);
+                        /* must delete to avoid corrupting pcp list */
+                        list_del(&page->lru);
+                        pcp->count--;
+
+                        if (bulkfree_pcp_prepare(page))
+                                continue;
+
+                        list_add_tail(&page->lru, &head);
+
+                        /*
+                         * We are going to put the page back to the global
+                         * pool, prefetch its buddy to speed up later access
+                         * under zone->lock. It is believed the overhead of
+                         * an additional test and calculating buddy_pfn here
+                         * can be offset by reduced memory latency later. To
+                         * avoid excessive prefetching due to large count, only
+                         * prefetch buddy for the first pcp->batch nr of pages.
+                         */
+                        if (prefetch_nr++ < pcp->batch)
+                                prefetch_buddy(page);
+                } while (--count && --batch_free && !list_empty(list));
+        }
+
+        spin_lock(&zone->lock);
+        isolated_pageblocks = has_isolate_pageblock(zone);
+
+        /*
+         * Use safe version since after __free_one_page(),
+         * page->lru.next will not point to original list.
+         */
+        list_for_each_entry_safe(page, tmp, &head, lru) {
+                int mt = get_pcppage_migratetype(page);
+                /* MIGRATE_ISOLATE page should not go to pcplists */
+                VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
+                /* Pageblock could have been isolated meanwhile */
+                if (unlikely(isolated_pageblocks))
+                        mt = get_pageblock_migratetype(page);
+
+                __free_one_page(page, page_to_pfn(page), zone, 0, mt, FPI_NONE);
+                trace_mm_page_pcpu_drain(page, 0, mt);
+        }
+        spin_unlock(&zone->lock);
+}
+
+static void free_one_page(struct zone *zone,
+                                struct page *page, unsigned long pfn,
+                                unsigned int order,
+                                int migratetype, fpi_t fpi_flags)
+{
+        spin_lock(&zone->lock);
+        if (unlikely(has_isolate_pageblock(zone) ||
+                is_migrate_isolate(migratetype))) {
+                migratetype = get_pfnblock_migratetype(page, pfn);
+        }
+        __free_one_page(page, pfn, zone, order, migratetype, fpi_flags);
+        spin_unlock(&zone->lock);
+}
+
+static void __meminit __init_single_page(struct page *page, unsigned long pfn,
+                                unsigned long zone, int nid)
+{
+        mm_zero_struct_page(page);
+        set_page_links(page, zone, nid, pfn);
+        init_page_count(page);
+        page_mapcount_reset(page);
+        page_cpupid_reset_last(page);
+        page_kasan_tag_reset(page);
+
+        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
+}
+
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+static void __meminit init_reserved_page(unsigned long pfn)
+{
+        pg_data_t *pgdat;
+        int nid, zid;
+
+        if (!early_page_uninitialised(pfn))
+                return;
+
+        nid = early_pfn_to_nid(pfn);
+        pgdat = NODE_DATA(nid);
+
+        for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+                struct zone *zone = &pgdat->node_zones[zid];
+
+                if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
+                        break;
+        }
+        __init_single_page(pfn_to_page(pfn), pfn, zid, nid);
+}
+#else
+static inline void init_reserved_page(unsigned long pfn)
+{
+}
+#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
+
+/*
+ * Initialised pages do not have PageReserved set. This function is
+ * called for each range allocated by the bootmem allocator and
+ * marks the pages PageReserved. The remaining valid pages are later
+ * sent to the buddy page allocator.
+ */
+void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
+{
+        unsigned long start_pfn = PFN_DOWN(start);
+        unsigned long end_pfn = PFN_UP(end);
+
+        for (; start_pfn < end_pfn; start_pfn++) {
+                if (pfn_valid(start_pfn)) {
+                        struct page *page = pfn_to_page(start_pfn);
+
+                        init_reserved_page(start_pfn);
+
+                        /* Avoid false-positive PageTail() */
+                        INIT_LIST_HEAD(&page->lru);
+
+                        /*
+                         * no need for atomic set_bit because the struct
+                         * page is not visible yet so nobody should
+                         * access it yet.
+                         */
+                        __SetPageReserved(page);
+                }
+        }
+}
+
+static void __free_pages_ok(struct page *page, unsigned int order,
+                            fpi_t fpi_flags)
+{
+        unsigned long flags;
+        int migratetype;
+        unsigned long pfn = page_to_pfn(page);
+
+        if (!free_pages_prepare(page, order, true))
+                return;
+
+        migratetype = get_pfnblock_migratetype(page, pfn);
+        local_irq_save(flags);
+        __count_vm_events(PGFREE, 1 << order);
+        free_one_page(page_zone(page), page, pfn, order, migratetype,
+                      fpi_flags);
+        local_irq_restore(flags);
+}
+
+void __free_pages_core(struct page *page, unsigned int order)
+{
+        unsigned int nr_pages = 1 << order;
+        struct page *p = page;
+        unsigned int loop;
+
+        /*
+         * When initializing the memmap, __init_single_page() sets the refcount
+         * of all pages to 1 ("allocated"/"not free"). We have to set the
+         * refcount of all involved pages to 0.
+         */
+        prefetchw(p);
+        for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
+                prefetchw(p + 1);
+                __ClearPageReserved(p);
+                set_page_count(p, 0);
+        }
+        __ClearPageReserved(p);
+        set_page_count(p, 0);
+
+        atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
+
+        /*
+         * Bypass PCP and place fresh pages right to the tail, primarily
+         * relevant for memory onlining.
+         */
+        __free_pages_ok(page, order, FPI_TO_TAIL);
+}
+
+#ifdef CONFIG_NEED_MULTIPLE_NODES
+
+static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
+
+#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
+
+/*
+ * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
+ */
+int __meminit __early_pfn_to_nid(unsigned long pfn,
+                                        struct mminit_pfnnid_cache *state)
+{
+        unsigned long start_pfn, end_pfn;
+        int nid;
+
+        if (state->last_start <= pfn && pfn < state->last_end)
+                return state->last_nid;
+
+        nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
+        if (nid != NUMA_NO_NODE) {
+                state->last_start = start_pfn;
+                state->last_end = end_pfn;
+                state->last_nid = nid;
+        }
+
+        return nid;
+}
+#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
+
+int __meminit early_pfn_to_nid(unsigned long pfn)
+{
+        static DEFINE_SPINLOCK(early_pfn_lock);
+        int nid;
+
+        spin_lock(&early_pfn_lock);
+        nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
+        if (nid < 0)
+                nid = first_online_node;
+        spin_unlock(&early_pfn_lock);
+
+        return nid;
+}
+#endif /* CONFIG_NEED_MULTIPLE_NODES */
+
+void __init memblock_free_pages(struct page *page, unsigned long pfn,
+                                                        unsigned int order)
+{
+        if (early_page_uninitialised(pfn))
+                return;
+        __free_pages_core(page, order);
+}
+
+/*
+ * Check that the whole (or subset of) a pageblock given by the interval of
+ * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
+ * with the migration of free compaction scanner. The scanners then need to
+ * use only pfn_valid_within() check for arches that allow holes within
+ * pageblocks.
+ *
+ * Return struct page pointer of start_pfn, or NULL if checks were not passed.
+ *
+ * It's possible on some configurations to have a setup like node0 node1 node0
+ * i.e. it's possible that all pages within a zones range of pages do not
+ * belong to a single zone. We assume that a border between node0 and node1
+ * can occur within a single pageblock, but not a node0 node1 node0
+ * interleaving within a single pageblock. It is therefore sufficient to check
+ * the first and last page of a pageblock and avoid checking each individual
+ * page in a pageblock.
+ */
+struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
+                                     unsigned long end_pfn, struct zone *zone)
+{
+        struct page *start_page;
+        struct page *end_page;
+
+        /* end_pfn is one past the range we are checking */
+        end_pfn--;
+
+        if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
+                return NULL;
+
+        start_page = pfn_to_online_page(start_pfn);
+        if (!start_page)
+                return NULL;
+
+        if (page_zone(start_page) != zone)
+                return NULL;
+
+        end_page = pfn_to_page(end_pfn);
+
+        /* This gives a shorter code than deriving page_zone(end_page) */
+        if (page_zone_id(start_page) != page_zone_id(end_page))
+                return NULL;
+
+        return start_page;
+}
+
+void set_zone_contiguous(struct zone *zone)
+{
+        unsigned long block_start_pfn = zone->zone_start_pfn;
+        unsigned long block_end_pfn;
+
+        block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages);
+        for (; block_start_pfn < zone_end_pfn(zone);
+                        block_start_pfn = block_end_pfn,
+                         block_end_pfn += pageblock_nr_pages) {
+
+                block_end_pfn = min(block_end_pfn, zone_end_pfn(zone));
+
+                if (!__pageblock_pfn_to_page(block_start_pfn,
+                                             block_end_pfn, zone))
+                        return;
+                cond_resched();
+        }
+
+        /* We confirm that there is no hole */
+        zone->contiguous = true;
+}
+
+void clear_zone_contiguous(struct zone *zone)
+{
+        zone->contiguous = false;
+}
+
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+static void __init deferred_free_range(unsigned long pfn,
+                                       unsigned long nr_pages)
+{
+        struct page *page;
+        unsigned long i;
+
+        if (!nr_pages)
+                return;
+
+        page = pfn_to_page(pfn);
+
+        /* Free a large naturally-aligned chunk if possible */
+        if (nr_pages == pageblock_nr_pages &&
+            (pfn & (pageblock_nr_pages - 1)) == 0) {
+                set_pageblock_migratetype(page, MIGRATE_MOVABLE);
+                __free_pages_core(page, pageblock_order);
+                return;
+        }
+
+        for (i = 0; i < nr_pages; i++, page++, pfn++) {
+                if ((pfn & (pageblock_nr_pages - 1)) == 0)
+                        set_pageblock_migratetype(page, MIGRATE_MOVABLE);
+                __free_pages_core(page, 0);
+        }
+}
+
+/* Completion tracking for deferred_init_memmap() threads */
+static atomic_t pgdat_init_n_undone __initdata;
+static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp);
+
+static inline void __init pgdat_init_report_one_done(void)
+{
+        if (atomic_dec_and_test(&pgdat_init_n_undone))
+                complete(&pgdat_init_all_done_comp);
+}
+
+/*
+ * Returns true if page needs to be initialized or freed to buddy allocator.
+ *
+ * First we check if pfn is valid on architectures where it is possible to have
+ * holes within pageblock_nr_pages. On systems where it is not possible, this
+ * function is optimized out.
+ *
+ * Then, we check if a current large page is valid by only checking the validity
+ * of the head pfn.
+ */
+static inline bool __init deferred_pfn_valid(unsigned long pfn)
+{
+        if (!pfn_valid_within(pfn))
+                return false;
+        if (!(pfn & (pageblock_nr_pages - 1)) && !pfn_valid(pfn))
+                return false;
+        return true;
+}
+
+/*
+ * Free pages to buddy allocator. Try to free aligned pages in
+ * pageblock_nr_pages sizes.
+ */
+static void __init deferred_free_pages(unsigned long pfn,
+                                       unsigned long end_pfn)
+{
+        unsigned long nr_pgmask = pageblock_nr_pages - 1;
+        unsigned long nr_free = 0;
+
+        for (; pfn < end_pfn; pfn++) {
+                if (!deferred_pfn_valid(pfn)) {
+                        deferred_free_range(pfn - nr_free, nr_free);
+                        nr_free = 0;
+                } else if (!(pfn & nr_pgmask)) {
+                        deferred_free_range(pfn - nr_free, nr_free);
+                        nr_free = 1;
+                } else {
+                        nr_free++;
+                }
+        }
+        /* Free the last block of pages to allocator */
+        deferred_free_range(pfn - nr_free, nr_free);
+}
+
+/*
+ * Initialize struct pages.  We minimize pfn page lookups and scheduler checks
+ * by performing it only once every pageblock_nr_pages.
+ * Return number of pages initialized.
+ */
+static unsigned long  __init deferred_init_pages(struct zone *zone,
+                                                 unsigned long pfn,
+                                                 unsigned long end_pfn)
+{
+        unsigned long nr_pgmask = pageblock_nr_pages - 1;
+        int nid = zone_to_nid(zone);
+        unsigned long nr_pages = 0;
+        int zid = zone_idx(zone);
+        struct page *page = NULL;
+
+        for (; pfn < end_pfn; pfn++) {
+                if (!deferred_pfn_valid(pfn)) {
+                        page = NULL;
+                        continue;
+                } else if (!page || !(pfn & nr_pgmask)) {
+                        page = pfn_to_page(pfn);
+                } else {
+                        page++;
+                }
+                __init_single_page(page, pfn, zid, nid);
+                nr_pages++;
+        }
+        return (nr_pages);
+}
+
+/*
+ * This function is meant to pre-load the iterator for the zone init.
+ * Specifically it walks through the ranges until we are caught up to the
+ * first_init_pfn value and exits there. If we never encounter the value we
+ * return false indicating there are no valid ranges left.
+ */
+static bool __init
+deferred_init_mem_pfn_range_in_zone(u64 *i, struct zone *zone,
+                                    unsigned long *spfn, unsigned long *epfn,
+                                    unsigned long first_init_pfn)
+{
+        u64 j;
+
+        /*
+         * Start out by walking through the ranges in this zone that have
+         * already been initialized. We don't need to do anything with them
+         * so we just need to flush them out of the system.
+         */
+        for_each_free_mem_pfn_range_in_zone(j, zone, spfn, epfn) {
+                if (*epfn <= first_init_pfn)
+                        continue;
+                if (*spfn < first_init_pfn)
+                        *spfn = first_init_pfn;
+                *i = j;
+                return true;
+        }
+
+        return false;
+}
+
+/*
+ * Initialize and free pages. We do it in two loops: first we initialize
+ * struct page, then free to buddy allocator, because while we are
+ * freeing pages we can access pages that are ahead (computing buddy
+ * page in __free_one_page()).
+ *
+ * In order to try and keep some memory in the cache we have the loop
+ * broken along max page order boundaries. This way we will not cause
+ * any issues with the buddy page computation.
+ */
+static unsigned long __init
+deferred_init_maxorder(u64 *i, struct zone *zone, unsigned long *start_pfn,
+                       unsigned long *end_pfn)
+{
+        unsigned long mo_pfn = ALIGN(*start_pfn + 1, MAX_ORDER_NR_PAGES);
+        unsigned long spfn = *start_pfn, epfn = *end_pfn;
+        unsigned long nr_pages = 0;
+        u64 j = *i;
+
+        /* First we loop through and initialize the page values */
+        for_each_free_mem_pfn_range_in_zone_from(j, zone, start_pfn, end_pfn) {
+                unsigned long t;
+
+                if (mo_pfn <= *start_pfn)
+                        break;
+
+                t = min(mo_pfn, *end_pfn);
+                nr_pages += deferred_init_pages(zone, *start_pfn, t);
+
+                if (mo_pfn < *end_pfn) {
+                        *start_pfn = mo_pfn;
+                        break;
+                }
+        }
+
+        /* Reset values and now loop through freeing pages as needed */
+        swap(j, *i);
+
+        for_each_free_mem_pfn_range_in_zone_from(j, zone, &spfn, &epfn) {
+                unsigned long t;
+
+                if (mo_pfn <= spfn)
+                        break;
+
+                t = min(mo_pfn, epfn);
+                deferred_free_pages(spfn, t);
+
+                if (mo_pfn <= epfn)
+                        break;
+        }
+
+        return nr_pages;
+}
+
+static void __init
+deferred_init_memmap_chunk(unsigned long start_pfn, unsigned long end_pfn,
+                           void *arg)
+{
+        unsigned long spfn, epfn;
+        struct zone *zone = arg;
+        u64 i;
+
+        deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, start_pfn);
+
+        /*
+         * Initialize and free pages in MAX_ORDER sized increments so that we
+         * can avoid introducing any issues with the buddy allocator.
+         */
+        while (spfn < end_pfn) {
+                deferred_init_maxorder(&i, zone, &spfn, &epfn);
+                cond_resched();
+        }
+}
+
+/* An arch may override for more concurrency. */
+__weak int __init
+deferred_page_init_max_threads(const struct cpumask *node_cpumask)
+{
+        return 1;
+}
+
+/* Initialise remaining memory on a node */
+static int __init deferred_init_memmap(void *data)
+{
+        pg_data_t *pgdat = data;
+        const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
+        unsigned long spfn = 0, epfn = 0;
+        unsigned long first_init_pfn, flags;
+        unsigned long start = jiffies;
+        struct zone *zone;
+        int zid, max_threads;
+        u64 i;
+
+        /* Bind memory initialisation thread to a local node if possible */
+        if (!cpumask_empty(cpumask))
+                set_cpus_allowed_ptr(current, cpumask);
+
+        pgdat_resize_lock(pgdat, &flags);
+        first_init_pfn = pgdat->first_deferred_pfn;
+        if (first_init_pfn == ULONG_MAX) {
+                pgdat_resize_unlock(pgdat, &flags);
+                pgdat_init_report_one_done();
+                return 0;
+        }
+
+        /* Sanity check boundaries */
+        BUG_ON(pgdat->first_deferred_pfn < pgdat->node_start_pfn);
+        BUG_ON(pgdat->first_deferred_pfn > pgdat_end_pfn(pgdat));
+        pgdat->first_deferred_pfn = ULONG_MAX;
+
+        /*
+         * Once we unlock here, the zone cannot be grown anymore, thus if an
+         * interrupt thread must allocate this early in boot, zone must be
+         * pre-grown prior to start of deferred page initialization.
+         */
+        pgdat_resize_unlock(pgdat, &flags);
+
+        /* Only the highest zone is deferred so find it */
+        for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+                zone = pgdat->node_zones + zid;
+                if (first_init_pfn < zone_end_pfn(zone))
+                        break;
+        }
+
+        /* If the zone is empty somebody else may have cleared out the zone */
+        if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
+                                                 first_init_pfn))
+                goto zone_empty;
+
+        max_threads = deferred_page_init_max_threads(cpumask);
+
+        while (spfn < epfn) {
+                unsigned long epfn_align = ALIGN(epfn, PAGES_PER_SECTION);
+                struct padata_mt_job job = {
+                        .thread_fn   = deferred_init_memmap_chunk,
+                        .fn_arg      = zone,
+                        .start       = spfn,
+                        .size        = epfn_align - spfn,
+                        .align       = PAGES_PER_SECTION,
+                        .min_chunk   = PAGES_PER_SECTION,
+                        .max_threads = max_threads,
+                };
+
+                padata_do_multithreaded(&job);
+                deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
+                                                    epfn_align);
+        }
+zone_empty:
+        /* Sanity check that the next zone really is unpopulated */
+        WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));
+
+        pr_info("node %d deferred pages initialised in %ums\n",
+                pgdat->node_id, jiffies_to_msecs(jiffies - start));
+
+        pgdat_init_report_one_done();
+        return 0;
+}
+
+/*
+ * If this zone has deferred pages, try to grow it by initializing enough
+ * deferred pages to satisfy the allocation specified by order, rounded up to
+ * the nearest PAGES_PER_SECTION boundary.  So we're adding memory in increments
+ * of SECTION_SIZE bytes by initializing struct pages in increments of
+ * PAGES_PER_SECTION * sizeof(struct page) bytes.
+ *
+ * Return true when zone was grown, otherwise return false. We return true even
+ * when we grow less than requested, to let the caller decide if there are
+ * enough pages to satisfy the allocation.
+ *
+ * Note: We use noinline because this function is needed only during boot, and
+ * it is called from a __ref function _deferred_grow_zone. This way we are
+ * making sure that it is not inlined into permanent text section.
+ */
+static noinline bool __init
+deferred_grow_zone(struct zone *zone, unsigned int order)
+{
+        unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION);
+        pg_data_t *pgdat = zone->zone_pgdat;
+        unsigned long first_deferred_pfn = pgdat->first_deferred_pfn;
+        unsigned long spfn, epfn, flags;
+        unsigned long nr_pages = 0;
+        u64 i;
+
+        /* Only the last zone may have deferred pages */
+        if (zone_end_pfn(zone) != pgdat_end_pfn(pgdat))
+                return false;
+
+        pgdat_resize_lock(pgdat, &flags);
+
+        /*
+         * If someone grew this zone while we were waiting for spinlock, return
+         * true, as there might be enough pages already.
+         */
+        if (first_deferred_pfn != pgdat->first_deferred_pfn) {
+                pgdat_resize_unlock(pgdat, &flags);
+                return true;
+        }
+
+        /* If the zone is empty somebody else may have cleared out the zone */
+        if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
+                                                 first_deferred_pfn)) {
+                pgdat->first_deferred_pfn = ULONG_MAX;
+                pgdat_resize_unlock(pgdat, &flags);
+                /* Retry only once. */
+                return first_deferred_pfn != ULONG_MAX;
+        }
+
+        /*
+         * Initialize and free pages in MAX_ORDER sized increments so
+         * that we can avoid introducing any issues with the buddy
+         * allocator.
+         */
+        while (spfn < epfn) {
+                /* update our first deferred PFN for this section */
+                first_deferred_pfn = spfn;
+
+                nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
+                touch_nmi_watchdog();
+
+                /* We should only stop along section boundaries */
+                if ((first_deferred_pfn ^ spfn) < PAGES_PER_SECTION)
+                        continue;
+
+                /* If our quota has been met we can stop here */
+                if (nr_pages >= nr_pages_needed)
+                        break;
+        }
+
+        pgdat->first_deferred_pfn = spfn;
+        pgdat_resize_unlock(pgdat, &flags);
+
+        return nr_pages > 0;
+}
+
+/*
+ * deferred_grow_zone() is __init, but it is called from
+ * get_page_from_freelist() during early boot until deferred_pages permanently
+ * disables this call. This is why we have refdata wrapper to avoid warning,
+ * and to ensure that the function body gets unloaded.
+ */
+static bool __ref
+_deferred_grow_zone(struct zone *zone, unsigned int order)
+{
+        return deferred_grow_zone(zone, order);
+}
+
+#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
+
+void __init page_alloc_init_late(void)
+{
+        struct zone *zone;
+        int nid;
+
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+
+        /* There will be num_node_state(N_MEMORY) threads */
+        atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY));
+        for_each_node_state(nid, N_MEMORY) {
+                kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid);
+        }
+
+        /* Block until all are initialised */
+        wait_for_completion(&pgdat_init_all_done_comp);
+
+        /*
+         * The number of managed pages has changed due to the initialisation
+         * so the pcpu batch and high limits needs to be updated or the limits
+         * will be artificially small.
+         */
+        for_each_populated_zone(zone)
+                zone_pcp_update(zone);
+
+        /*
+         * We initialized the rest of the deferred pages.  Permanently disable
+         * on-demand struct page initialization.
+         */
+        static_branch_disable(&deferred_pages);
+
+        /* Reinit limits that are based on free pages after the kernel is up */
+        files_maxfiles_init();
+#endif
+
+        /* Discard memblock private memory */
+        memblock_discard();
+
+        for_each_node_state(nid, N_MEMORY)
+                shuffle_free_memory(NODE_DATA(nid));
+
+        for_each_populated_zone(zone)
+                set_zone_contiguous(zone);
+}
+
+#ifdef CONFIG_CMA
+/* Free whole pageblock and set its migration type to MIGRATE_CMA. */
+void __init init_cma_reserved_pageblock(struct page *page)
+{
+        unsigned i = pageblock_nr_pages;
+        struct page *p = page;
+
+        do {
+                __ClearPageReserved(p);
+                set_page_count(p, 0);
+        } while (++p, --i);
+
+        set_pageblock_migratetype(page, MIGRATE_CMA);
+
+        if (pageblock_order >= MAX_ORDER) {
+                i = pageblock_nr_pages;
+                p = page;
+                do {
+                        set_page_refcounted(p);
+                        __free_pages(p, MAX_ORDER - 1);
+                        p += MAX_ORDER_NR_PAGES;
+                } while (i -= MAX_ORDER_NR_PAGES);
+        } else {
+                set_page_refcounted(page);
+                __free_pages(page, pageblock_order);
+        }
+
+        adjust_managed_page_count(page, pageblock_nr_pages);
+}
+#endif
+
+/*
+ * 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.
+ *
+ * -- nyc
+ */
+static inline void expand(struct zone *zone, struct page *page,
+        int low, int high, int migratetype)
+{
+        unsigned long size = 1 << high;
+
+        while (high > low) {
+                high--;
+                size >>= 1;
+                VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
+
+                /*
+                 * Mark as guard pages (or page), that will allow to
+                 * merge back to allocator when buddy will be freed.
+                 * Corresponding page table entries will not be touched,
+                 * pages will stay not present in virtual address space
+                 */
+                if (set_page_guard(zone, &page[size], high, migratetype))
+                        continue;
+
+                add_to_free_list(&page[size], zone, high, migratetype);
+                set_buddy_order(&page[size], high);
+        }
+}
+
+static void check_new_page_bad(struct page *page)
+{
+        if (unlikely(page->flags & __PG_HWPOISON)) {
+                /* Don't complain about hwpoisoned pages */
+                page_mapcount_reset(page); /* remove PageBuddy */
+                return;
+        }
+
+        bad_page(page,
+                 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP));
+}
+
+/*
+ * This page is about to be returned from the page allocator
+ */
+static inline int check_new_page(struct page *page)
+{
+        if (likely(page_expected_state(page,
+                                PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON)))
+                return 0;
+
+        check_new_page_bad(page);
+        return 1;
+}
+
+static inline bool free_pages_prezeroed(void)
+{
+        return (IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) &&
+                page_poisoning_enabled()) || want_init_on_free();
+}
+
+#ifdef CONFIG_DEBUG_VM
+/*
+ * With DEBUG_VM enabled, order-0 pages are checked for expected state when
+ * being allocated from pcp lists. With debug_pagealloc also enabled, they are
+ * also checked when pcp lists are refilled from the free lists.
+ */
+static inline bool check_pcp_refill(struct page *page)
+{
+        if (debug_pagealloc_enabled_static())
+                return check_new_page(page);
+        else
+                return false;
+}
+
+static inline bool check_new_pcp(struct page *page)
+{
+        return check_new_page(page);
+}
+#else
+/*
+ * With DEBUG_VM disabled, free order-0 pages are checked for expected state
+ * when pcp lists are being refilled from the free lists. With debug_pagealloc
+ * enabled, they are also checked when being allocated from the pcp lists.
+ */
+static inline bool check_pcp_refill(struct page *page)
+{
+        return check_new_page(page);
+}
+static inline bool check_new_pcp(struct page *page)
+{
+        if (debug_pagealloc_enabled_static())
+                return check_new_page(page);
+        else
+                return false;
+}
+#endif /* CONFIG_DEBUG_VM */
+
+static bool check_new_pages(struct page *page, unsigned int order)
+{
+        int i;
+        for (i = 0; i < (1 << order); i++) {
+                struct page *p = page + i;
+
+                if (unlikely(check_new_page(p)))
+                        return true;
+        }
+
+        return false;
+}
+
+inline void post_alloc_hook(struct page *page, unsigned int order,
+                                gfp_t gfp_flags)
+{
+        set_page_private(page, 0);
+        set_page_refcounted(page);
+
+        arch_alloc_page(page, order);
+        if (debug_pagealloc_enabled_static())
+                kernel_map_pages(page, 1 << order, 1);
+        kasan_alloc_pages(page, order);
+        kernel_poison_pages(page, 1 << order, 1);
+        set_page_owner(page, order, gfp_flags);
+}
+
+static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
+                                                        unsigned int alloc_flags)
+{
+        post_alloc_hook(page, order, gfp_flags);
+
+        if (!free_pages_prezeroed() && want_init_on_alloc(gfp_flags))
+                kernel_init_free_pages(page, 1 << order);
+
+        if (order && (gfp_flags & __GFP_COMP))
+                prep_compound_page(page, order);
+
+        /*
+         * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
+         * allocate the page. The expectation is that the caller is taking
+         * steps that will free more memory. The caller should avoid the page
+         * being used for !PFMEMALLOC purposes.
+         */
+        if (alloc_flags & ALLOC_NO_WATERMARKS)
+                set_page_pfmemalloc(page);
+        else
+                clear_page_pfmemalloc(page);
+}
+
+/*
+ * Go through the free lists for the given migratetype and remove
+ * the smallest available page from the freelists
+ */
+static __always_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]);
+                page = get_page_from_free_area(area, migratetype);
+                if (!page)
+                        continue;
+                del_page_from_free_list(page, zone, current_order);
+                expand(zone, page, order, current_order, migratetype);
+                set_pcppage_migratetype(page, 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][3] = {
+        [MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_TYPES },
+        [MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
+        [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_TYPES },
+#ifdef CONFIG_CMA
+        [MIGRATE_CMA]         = { MIGRATE_TYPES }, /* Never used */
+#endif
+#ifdef CONFIG_MEMORY_ISOLATION
+        [MIGRATE_ISOLATE]     = { MIGRATE_TYPES }, /* Never used */
+#endif
+};
+
+#ifdef CONFIG_CMA
+static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone,
+                                        unsigned int order)
+{
+        return __rmqueue_smallest(zone, order, MIGRATE_CMA);
+}
+#else
+static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
+                                        unsigned int order) { return NULL; }
+#endif
+
+/*
+ * Move the free pages in a range to the freelist tail 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,
+                          unsigned long start_pfn, unsigned long end_pfn,
+                          int migratetype, int *num_movable)
+{
+        struct page *page;
+        unsigned long pfn;
+        unsigned int order;
+        int pages_moved = 0;
+
+        for (pfn = start_pfn; pfn <= end_pfn;) {
+                if (!pfn_valid_within(pfn)) {
+                        pfn++;
+                        continue;
+                }
+
+                page = pfn_to_page(pfn);
+                if (!PageBuddy(page)) {
+                        /*
+                         * We assume that pages that could be isolated for
+                         * migration are movable. But we don't actually try
+                         * isolating, as that would be expensive.
+                         */
+                        if (num_movable &&
+                                        (PageLRU(page) || __PageMovable(page)))
+                                (*num_movable)++;
+                        pfn++;
+                        continue;
+                }
+
+                /* Make sure we are not inadvertently changing nodes */
+                VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
+                VM_BUG_ON_PAGE(page_zone(page) != zone, page);
+
+                order = buddy_order(page);
+                move_to_free_list(page, zone, order, migratetype);
+                pfn += 1 << order;
+                pages_moved += 1 << order;
+        }
+
+        return pages_moved;
+}
+
+int move_freepages_block(struct zone *zone, struct page *page,
+                                int migratetype, int *num_movable)
+{
+        unsigned long start_pfn, end_pfn, pfn;
+
+        if (num_movable)
+                *num_movable = 0;
+
+        pfn = page_to_pfn(page);
+        start_pfn = pfn & ~(pageblock_nr_pages - 1);
+        end_pfn = start_pfn + pageblock_nr_pages - 1;
+
+        /* Do not cross zone boundaries */
+        if (!zone_spans_pfn(zone, start_pfn))
+                start_pfn = pfn;
+        if (!zone_spans_pfn(zone, end_pfn))
+                return 0;
+
+        return move_freepages(zone, start_pfn, end_pfn, migratetype,
+                                                                num_movable);
+}
+
+static void change_pageblock_range(struct page *pageblock_page,
+                                        int start_order, int migratetype)
+{
+        int nr_pageblocks = 1 << (start_order - pageblock_order);
+
+        while (nr_pageblocks--) {
+                set_pageblock_migratetype(pageblock_page, migratetype);
+                pageblock_page += pageblock_nr_pages;
+        }
+}
+
+/*
+ * When we are falling back to another migratetype during allocation, try to
+ * steal extra free pages from the same pageblocks to satisfy further
+ * allocations, instead of polluting multiple pageblocks.
+ *
+ * If we are stealing a relatively large buddy page, it is likely there will
+ * be more free pages in the pageblock, so try to steal them all. For
+ * reclaimable and unmovable allocations, we steal regardless of page size,
+ * as fragmentation caused by those allocations polluting movable pageblocks
+ * is worse than movable allocations stealing from unmovable and reclaimable
+ * pageblocks.
+ */
+static bool can_steal_fallback(unsigned int order, int start_mt)
+{
+        /*
+         * Leaving this order check is intended, although there is
+         * relaxed order check in next check. The reason is that
+         * we can actually steal whole pageblock if this condition met,
+         * but, below check doesn't guarantee it and that is just heuristic
+         * so could be changed anytime.
+         */
+        if (order >= pageblock_order)
+                return true;
+
+        if (order >= pageblock_order / 2 ||
+                start_mt == MIGRATE_RECLAIMABLE ||
+                start_mt == MIGRATE_UNMOVABLE ||
+                page_group_by_mobility_disabled)
+                return true;
+
+        return false;
+}
+
+static inline bool boost_watermark(struct zone *zone)
+{
+        unsigned long max_boost;
+
+        if (!watermark_boost_factor)
+                return false;
+        /*
+         * Don't bother in zones that are unlikely to produce results.
+         * On small machines, including kdump capture kernels running
+         * in a small area, boosting the watermark can cause an out of
+         * memory situation immediately.
+         */
+        if ((pageblock_nr_pages * 4) > zone_managed_pages(zone))
+                return false;
+
+        max_boost = mult_frac(zone->_watermark[WMARK_HIGH],
+                        watermark_boost_factor, 10000);
+
+        /*
+         * high watermark may be uninitialised if fragmentation occurs
+         * very early in boot so do not boost. We do not fall
+         * through and boost by pageblock_nr_pages as failing
+         * allocations that early means that reclaim is not going
+         * to help and it may even be impossible to reclaim the
+         * boosted watermark resulting in a hang.
+         */
+        if (!max_boost)
+                return false;
+
+        max_boost = max(pageblock_nr_pages, max_boost);
+
+        zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages,
+                max_boost);
+
+        return true;
+}
+
+/*
+ * This function implements actual steal behaviour. If order is large enough,
+ * we can steal whole pageblock. If not, we first move freepages in this
+ * pageblock to our migratetype and determine how many already-allocated pages
+ * are there in the pageblock with a compatible migratetype. If at least half
+ * of pages are free or compatible, we can change migratetype of the pageblock
+ * itself, so pages freed in the future will be put on the correct free list.
+ */
+static void steal_suitable_fallback(struct zone *zone, struct page *page,
+                unsigned int alloc_flags, int start_type, bool whole_block)
+{
+        unsigned int current_order = buddy_order(page);
+        int free_pages, movable_pages, alike_pages;
+        int old_block_type;
+
+        old_block_type = get_pageblock_migratetype(page);
+
+        /*
+         * This can happen due to races and we want to prevent broken
+         * highatomic accounting.
+         */
+        if (is_migrate_highatomic(old_block_type))
+                goto single_page;
+
+        /* Take ownership for orders >= pageblock_order */
+        if (current_order >= pageblock_order) {
+                change_pageblock_range(page, current_order, start_type);
+                goto single_page;
+        }
+
+        /*
+         * Boost watermarks to increase reclaim pressure to reduce the
+         * likelihood of future fallbacks. Wake kswapd now as the node
+         * may be balanced overall and kswapd will not wake naturally.
+         */
+        if (boost_watermark(zone) && (alloc_flags & ALLOC_KSWAPD))
+                set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
+
+        /* We are not allowed to try stealing from the whole block */
+        if (!whole_block)
+                goto single_page;
+
+        free_pages = move_freepages_block(zone, page, start_type,
+                                                &movable_pages);
+        /*
+         * Determine how many pages are compatible with our allocation.
+         * For movable allocation, it's the number of movable pages which
+         * we just obtained. For other types it's a bit more tricky.
+         */
+        if (start_type == MIGRATE_MOVABLE) {
+                alike_pages = movable_pages;
+        } else {
+                /*
+                 * If we are falling back a RECLAIMABLE or UNMOVABLE allocation
+                 * to MOVABLE pageblock, consider all non-movable pages as
+                 * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or
+                 * vice versa, be conservative since we can't distinguish the
+                 * exact migratetype of non-movable pages.
+                 */
+                if (old_block_type == MIGRATE_MOVABLE)
+                        alike_pages = pageblock_nr_pages
+                                                - (free_pages + movable_pages);
+                else
+                        alike_pages = 0;
+        }
+
+        /* moving whole block can fail due to zone boundary conditions */
+        if (!free_pages)
+                goto single_page;
+
+        /*
+         * If a sufficient number of pages in the block are either free or of
+         * comparable migratability as our allocation, claim the whole block.
+         */
+        if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||
+                        page_group_by_mobility_disabled)
+                set_pageblock_migratetype(page, start_type);
+
+        return;
+
+single_page:
+        move_to_free_list(page, zone, current_order, start_type);
+}
+
+/*
+ * Check whether there is a suitable fallback freepage with requested order.
+ * If only_stealable is true, this function returns fallback_mt only if
+ * we can steal other freepages all together. This would help to reduce
+ * fragmentation due to mixed migratetype pages in one pageblock.
+ */
+int find_suitable_fallback(struct free_area *area, unsigned int order,
+                        int migratetype, bool only_stealable, bool *can_steal)
+{
+        int i;
+        int fallback_mt;
+
+        if (area->nr_free == 0)
+                return -1;
+
+        *can_steal = false;
+        for (i = 0;; i++) {
+                fallback_mt = fallbacks[migratetype][i];
+                if (fallback_mt == MIGRATE_TYPES)
+                        break;
+
+                if (free_area_empty(area, fallback_mt))
+                        continue;
+
+                if (can_steal_fallback(order, migratetype))
+                        *can_steal = true;
+
+                if (!only_stealable)
+                        return fallback_mt;
+
+                if (*can_steal)
+                        return fallback_mt;
+        }
+
+        return -1;
+}
+
+/*
+ * Reserve a pageblock for exclusive use of high-order atomic allocations if
+ * there are no empty page blocks that contain a page with a suitable order
+ */
+static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
+                                unsigned int alloc_order)
+{
+        int mt;
+        unsigned long max_managed, flags;
+
+        /*
+         * Limit the number reserved to 1 pageblock or roughly 1% of a zone.
+         * Check is race-prone but harmless.
+         */
+        max_managed = (zone_managed_pages(zone) / 100) + pageblock_nr_pages;
+        if (zone->nr_reserved_highatomic >= max_managed)
+                return;
+
+        spin_lock_irqsave(&zone->lock, flags);
+
+        /* Recheck the nr_reserved_highatomic limit under the lock */
+        if (zone->nr_reserved_highatomic >= max_managed)
+                goto out_unlock;
+
+        /* Yoink! */
+        mt = get_pageblock_migratetype(page);
+        if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt)
+            && !is_migrate_cma(mt)) {
+                zone->nr_reserved_highatomic += pageblock_nr_pages;
+                set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
+                move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL);
+        }
+
+out_unlock:
+        spin_unlock_irqrestore(&zone->lock, flags);
+}
+
+/*
+ * Used when an allocation is about to fail under memory pressure. This
+ * potentially hurts the reliability of high-order allocations when under
+ * intense memory pressure but failed atomic allocations should be easier
+ * to recover from than an OOM.
+ *
+ * If @force is true, try to unreserve a pageblock even though highatomic
+ * pageblock is exhausted.
+ */
+static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
+                                                bool force)
+{
+        struct zonelist *zonelist = ac->zonelist;
+        unsigned long flags;
+        struct zoneref *z;
+        struct zone *zone;
+        struct page *page;
+        int order;
+        bool ret;
+
+        for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->highest_zoneidx,
+                                                                ac->nodemask) {
+                /*
+                 * Preserve at least one pageblock unless memory pressure
+                 * is really high.
+                 */
+                if (!force && zone->nr_reserved_highatomic <=
+                                        pageblock_nr_pages)
+                        continue;
+
+                spin_lock_irqsave(&zone->lock, flags);
+                for (order = 0; order < MAX_ORDER; order++) {
+                        struct free_area *area = &(zone->free_area[order]);
+
+                        page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
+                        if (!page)
+                                continue;
+
+                        /*
+                         * In page freeing path, migratetype change is racy so
+                         * we can counter several free pages in a pageblock
+                         * in this loop althoug we changed the pageblock type
+                         * from highatomic to ac->migratetype. So we should
+                         * adjust the count once.
+                         */
+                        if (is_migrate_highatomic_page(page)) {
+                                /*
+                                 * It should never happen but changes to
+                                 * locking could inadvertently allow a per-cpu
+                                 * drain to add pages to MIGRATE_HIGHATOMIC
+                                 * while unreserving so be safe and watch for
+                                 * underflows.
+                                 */
+                                zone->nr_reserved_highatomic -= min(
+                                                pageblock_nr_pages,
+                                                zone->nr_reserved_highatomic);
+                        }
+
+                        /*
+                         * Convert to ac->migratetype and avoid the normal
+                         * pageblock stealing heuristics. Minimally, the caller
+                         * is doing the work and needs the pages. More
+                         * importantly, if the block was always converted to
+                         * MIGRATE_UNMOVABLE or another type then the number
+                         * of pageblocks that cannot be completely freed
+                         * may increase.
+                         */
+                        set_pageblock_migratetype(page, ac->migratetype);
+                        ret = move_freepages_block(zone, page, ac->migratetype,
+                                                                        NULL);
+                        if (ret) {
+                                spin_unlock_irqrestore(&zone->lock, flags);
+                                return ret;
+                        }
+                }
+                spin_unlock_irqrestore(&zone->lock, flags);
+        }
+
+        return false;
+}
+
+/*
+ * Try finding a free buddy page on the fallback list and put it on the free
+ * list of requested migratetype, possibly along with other pages from the same
+ * block, depending on fragmentation avoidance heuristics. Returns true if
+ * fallback was found so that __rmqueue_smallest() can grab it.
+ *
+ * The use of signed ints for order and current_order is a deliberate
+ * deviation from the rest of this file, to make the for loop
+ * condition simpler.
+ */
+static __always_inline bool
+__rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
+                                                unsigned int alloc_flags)
+{
+        struct free_area *area;
+        int current_order;
+        int min_order = order;
+        struct page *page;
+        int fallback_mt;
+        bool can_steal;
+
+        /*
+         * Do not steal pages from freelists belonging to other pageblocks
+         * i.e. orders < pageblock_order. If there are no local zones free,
+         * the zonelists will be reiterated without ALLOC_NOFRAGMENT.
+         */
+        if (alloc_flags & ALLOC_NOFRAGMENT)
+                min_order = pageblock_order;
+
+        /*
+         * Find the largest available free page in the other list. This roughly
+         * approximates finding the pageblock with the most free pages, which
+         * would be too costly to do exactly.
+         */
+        for (current_order = MAX_ORDER - 1; current_order >= min_order;
+                                --current_order) {
+                area = &(zone->free_area[current_order]);
+                fallback_mt = find_suitable_fallback(area, current_order,
+                                start_migratetype, false, &can_steal);
+                if (fallback_mt == -1)
+                        continue;
+
+                /*
+                 * We cannot steal all free pages from the pageblock and the
+                 * requested migratetype is movable. In that case it's better to
+                 * steal and split the smallest available page instead of the
+                 * largest available page, because even if the next movable
+                 * allocation falls back into a different pageblock than this
+                 * one, it won't cause permanent fragmentation.
+                 */
+                if (!can_steal && start_migratetype == MIGRATE_MOVABLE
+                                        && current_order > order)
+                        goto find_smallest;
+
+                goto do_steal;
+        }
+
+        return false;
+
+find_smallest:
+        for (current_order = order; current_order < MAX_ORDER;
+                                                        current_order++) {
+                area = &(zone->free_area[current_order]);
+                fallback_mt = find_suitable_fallback(area, current_order,
+                                start_migratetype, false, &can_steal);
+                if (fallback_mt != -1)
+                        break;
+        }
+
+        /*
+         * This should not happen - we already found a suitable fallback
+         * when looking for the largest page.
+         */
+        VM_BUG_ON(current_order == MAX_ORDER);
+
+do_steal:
+        page = get_page_from_free_area(area, fallback_mt);
+
+        steal_suitable_fallback(zone, page, alloc_flags, start_migratetype,
+                                                                can_steal);
+
+        trace_mm_page_alloc_extfrag(page, order, current_order,
+                start_migratetype, fallback_mt);
+
+        return true;
+
+}
+
+static __always_inline struct page *
+__rmqueue_with_cma_reuse(struct zone *zone, unsigned int order,
+                                        int migratetype, unsigned int alloc_flags)
+{
+        struct page *page = NULL;
+retry:
+        page = __rmqueue_smallest(zone, order, migratetype);
+
+        if (unlikely(!page) && is_migrate_cma(migratetype)) {
+                migratetype = MIGRATE_MOVABLE;
+                alloc_flags &= ~ALLOC_CMA;
+                page = __rmqueue_smallest(zone, order, migratetype);
+        }
+
+        if (unlikely(!page) &&
+                __rmqueue_fallback(zone, order, migratetype, alloc_flags))
+                goto retry;
+
+        return page;
+}
+
+/*
+ * Do the hard work of removing an element from the buddy allocator.
+ * Call me with the zone->lock already held.
+ */
+static __always_inline struct page *
+__rmqueue(struct zone *zone, unsigned int order, int migratetype,
+                                                unsigned int alloc_flags)
+{
+        struct page *page;
+
+#ifdef CONFIG_CMA_REUSE
+        page = __rmqueue_with_cma_reuse(zone, order, migratetype, alloc_flags);
+        goto out;
+#endif
+
+        if (IS_ENABLED(CONFIG_CMA)) {
+                /*
+                 * Balance movable allocations between regular and CMA areas by
+                 * allocating from CMA when over half of the zone's free memory
+                 * is in the CMA area.
+                 */
+                if (alloc_flags & ALLOC_CMA &&
+                    zone_page_state(zone, NR_FREE_CMA_PAGES) >
+                    zone_page_state(zone, NR_FREE_PAGES) / 2) {
+                        page = __rmqueue_cma_fallback(zone, order);
+                        if (page)
+                                goto out;
+                }
+        }
+retry:
+        page = __rmqueue_smallest(zone, order, migratetype);
+        if (unlikely(!page)) {
+                if (alloc_flags & ALLOC_CMA)
+                        page = __rmqueue_cma_fallback(zone, order);
+
+                if (!page && __rmqueue_fallback(zone, order, migratetype,
+                                                                alloc_flags))
+                        goto retry;
+        }
+out:
+        if (page)
+                trace_mm_page_alloc_zone_locked(page, order, migratetype);
+        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, unsigned int alloc_flags)
+{
+        int i, alloced = 0;
+
+        spin_lock(&zone->lock);
+        for (i = 0; i < count; ++i) {
+                struct page *page = __rmqueue(zone, order, migratetype,
+                                                                alloc_flags);
+                if (unlikely(page == NULL))
+                        break;
+
+                if (unlikely(check_pcp_refill(page)))
+                        continue;
+
+                /*
+                 * Split buddy pages returned by expand() are received here in
+                 * physical page order. The page is added to the tail of
+                 * caller's list. From the callers perspective, the linked list
+                 * is ordered by page number under some conditions. This is
+                 * useful for IO devices that can forward direction from the
+                 * head, thus also in the physical page order. This is useful
+                 * for IO devices that can merge IO requests if the physical
+                 * pages are ordered properly.
+                 */
+                list_add_tail(&page->lru, list);
+                alloced++;
+                if (is_migrate_cma(get_pcppage_migratetype(page)))
+                        __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
+                                              -(1 << order));
+        }
+
+        /*
+         * i pages were removed from the buddy list even if some leak due
+         * to check_pcp_refill failing so adjust NR_FREE_PAGES based
+         * on i. Do not confuse with 'alloced' which is the number of
+         * pages added to the pcp list.
+         */
+        __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
+        spin_unlock(&zone->lock);
+        return alloced;
+}
+
+#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, batch;
+
+        local_irq_save(flags);
+        batch = READ_ONCE(pcp->batch);
+        to_drain = min(pcp->count, batch);
+        if (to_drain > 0)
+                free_pcppages_bulk(zone, to_drain, pcp);
+        local_irq_restore(flags);
+}
+#endif
+
+/*
+ * Drain pcplists of the indicated processor and zone.
+ *
+ * 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_zone(unsigned int cpu, struct zone *zone)
+{
+        unsigned long flags;
+        struct per_cpu_pageset *pset;
+        struct per_cpu_pages *pcp;
+
+        local_irq_save(flags);
+        pset = per_cpu_ptr(zone->pageset, cpu);
+
+        pcp = &pset->pcp;
+        if (pcp->count)
+                free_pcppages_bulk(zone, pcp->count, pcp);
+        local_irq_restore(flags);
+}
+
+/*
+ * Drain pcplists of all zones on 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)
+{
+        struct zone *zone;
+
+        for_each_populated_zone(zone) {
+                drain_pages_zone(cpu, zone);
+        }
+}
+
+/*
+ * Spill all of this CPU's per-cpu pages back into the buddy allocator.
+ *
+ * The CPU has to be pinned. When zone parameter is non-NULL, spill just
+ * the single zone's pages.
+ */
+void drain_local_pages(struct zone *zone)
+{
+        int cpu = smp_processor_id();
+
+        if (zone)
+                drain_pages_zone(cpu, zone);
+        else
+                drain_pages(cpu);
+}
+
+static void drain_local_pages_wq(struct work_struct *work)
+{
+        struct pcpu_drain *drain;
+
+        drain = container_of(work, struct pcpu_drain, work);
+
+        /*
+         * drain_all_pages doesn't use proper cpu hotplug protection so
+         * we can race with cpu offline when the WQ can move this from
+         * a cpu pinned worker to an unbound one. We can operate on a different
+         * cpu which is allright but we also have to make sure to not move to
+         * a different one.
+         */
+        preempt_disable();
+        drain_local_pages(drain->zone);
+        preempt_enable();
+}
+
+/*
+ * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
+ *
+ * When zone parameter is non-NULL, spill just the single zone's pages.
+ *
+ * Note that this can be extremely slow as the draining happens in a workqueue.
+ */
+void drain_all_pages(struct zone *zone)
+{
+        int cpu;
+
+        /*
+         * Allocate in the BSS so we wont require allocation in
+         * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
+         */
+        static cpumask_t cpus_with_pcps;
+
+        /*
+         * Make sure nobody triggers this path before mm_percpu_wq is fully
+         * initialized.
+         */
+        if (WARN_ON_ONCE(!mm_percpu_wq))
+                return;
+
+        /*
+         * Do not drain if one is already in progress unless it's specific to
+         * a zone. Such callers are primarily CMA and memory hotplug and need
+         * the drain to be complete when the call returns.
+         */
+        if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) {
+                if (!zone)
+                        return;
+                mutex_lock(&pcpu_drain_mutex);
+        }
+
+        /*
+         * We don't care about racing with CPU hotplug event
+         * as offline notification will cause the notified
+         * cpu to drain that CPU pcps and on_each_cpu_mask
+         * disables preemption as part of its processing
+         */
+        for_each_online_cpu(cpu) {
+                struct per_cpu_pageset *pcp;
+                struct zone *z;
+                bool has_pcps = false;
+
+                if (zone) {
+                        pcp = per_cpu_ptr(zone->pageset, cpu);
+                        if (pcp->pcp.count)
+                                has_pcps = true;
+                } else {
+                        for_each_populated_zone(z) {
+                                pcp = per_cpu_ptr(z->pageset, cpu);
+                                if (pcp->pcp.count) {
+                                        has_pcps = true;
+                                        break;
+                                }
+                        }
+                }
+
+                if (has_pcps)
+                        cpumask_set_cpu(cpu, &cpus_with_pcps);
+                else
+                        cpumask_clear_cpu(cpu, &cpus_with_pcps);
+        }
+
+        for_each_cpu(cpu, &cpus_with_pcps) {
+                struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu);
+
+                drain->zone = zone;
+                INIT_WORK(&drain->work, drain_local_pages_wq);
+                queue_work_on(cpu, mm_percpu_wq, &drain->work);
+        }
+        for_each_cpu(cpu, &cpus_with_pcps)
+                flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work);
+
+        mutex_unlock(&pcpu_drain_mutex);
+}
+
+#ifdef CONFIG_HIBERNATION
+
+/*
+ * Touch the watchdog for every WD_PAGE_COUNT pages.
+ */
+#define WD_PAGE_COUNT   (128*1024)
+
+void mark_free_pages(struct zone *zone)
+{
+        unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
+        unsigned long flags;
+        unsigned int order, t;
+        struct page *page;
+
+        if (zone_is_empty(zone))
+                return;
+
+        spin_lock_irqsave(&zone->lock, flags);
+
+        max_zone_pfn = zone_end_pfn(zone);
+        for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
+                if (pfn_valid(pfn)) {
+                        page = pfn_to_page(pfn);
+
+                        if (!--page_count) {
+                                touch_nmi_watchdog();
+                                page_count = WD_PAGE_COUNT;
+                        }
+
+                        if (page_zone(page) != zone)
+                                continue;
+
+                        if (!swsusp_page_is_forbidden(page))
+                                swsusp_unset_page_free(page);
+                }
+
+        for_each_migratetype_order(order, t) {
+                list_for_each_entry(page,
+                                &zone->free_area[order].free_list[t], lru) {
+                        unsigned long i;
+
+                        pfn = page_to_pfn(page);
+                        for (i = 0; i < (1UL << order); i++) {
+                                if (!--page_count) {
+                                        touch_nmi_watchdog();
+                                        page_count = WD_PAGE_COUNT;
+                                }
+                                swsusp_set_page_free(pfn_to_page(pfn + i));
+                        }
+                }
+        }
+        spin_unlock_irqrestore(&zone->lock, flags);
+}
+#endif /* CONFIG_PM */
+
+static bool free_unref_page_prepare(struct page *page, unsigned long pfn)
+{
+        int migratetype;
+
+        if (!free_pcp_prepare(page))
+                return false;
+
+        migratetype = get_pfnblock_migratetype(page, pfn);
+        set_pcppage_migratetype(page, migratetype);
+        return true;
+}
+
+static void free_unref_page_commit(struct page *page, unsigned long pfn)
+{
+        struct zone *zone = page_zone(page);
+        struct per_cpu_pages *pcp;
+        int migratetype;
+
+        migratetype = get_pcppage_migratetype(page);
+        __count_vm_event(PGFREE);
+
+        /*
+         * We only track unmovable, reclaimable and movable on pcp lists.
+         * Free ISOLATE pages back to the allocator because they are being
+         * offlined but treat HIGHATOMIC as movable pages so we can get those
+         * areas back if necessary. Otherwise, we may have to free
+         * excessively into the page allocator
+         */
+        if (migratetype >= MIGRATE_PCPTYPES) {
+                if (unlikely(is_migrate_isolate(migratetype))) {
+                        free_one_page(zone, page, pfn, 0, migratetype,
+                                      FPI_NONE);
+                        return;
+                }
+                migratetype = MIGRATE_MOVABLE;
+        }
+
+        pcp = &this_cpu_ptr(zone->pageset)->pcp;
+        list_add(&page->lru, &pcp->lists[migratetype]);
+        pcp->count++;
+        if (pcp->count >= pcp->high) {
+                unsigned long batch = READ_ONCE(pcp->batch);
+                free_pcppages_bulk(zone, batch, pcp);
+        }
+}
+
+/*
+ * Free a 0-order page
+ */
+void free_unref_page(struct page *page)
+{
+        unsigned long flags;
+        unsigned long pfn = page_to_pfn(page);
+
+        if (!free_unref_page_prepare(page, pfn))
+                return;
+
+        local_irq_save(flags);
+        free_unref_page_commit(page, pfn);
+        local_irq_restore(flags);
+}
+
+/*
+ * Free a list of 0-order pages
+ */
+void free_unref_page_list(struct list_head *list)
+{
+        struct page *page, *next;
+        unsigned long flags, pfn;
+        int batch_count = 0;
+
+        /* Prepare pages for freeing */
+        list_for_each_entry_safe(page, next, list, lru) {
+                pfn = page_to_pfn(page);
+                if (!free_unref_page_prepare(page, pfn))
+                        list_del(&page->lru);
+                set_page_private(page, pfn);
+        }
+
+        local_irq_save(flags);
+        list_for_each_entry_safe(page, next, list, lru) {
+                unsigned long pfn = page_private(page);
+
+                set_page_private(page, 0);
+                trace_mm_page_free_batched(page);
+                free_unref_page_commit(page, pfn);
+
+                /*
+                 * Guard against excessive IRQ disabled times when we get
+                 * a large list of pages to free.
+                 */
+                if (++batch_count == SWAP_CLUSTER_MAX) {
+                        local_irq_restore(flags);
+                        batch_count = 0;
+                        local_irq_save(flags);
+                }
+        }
+        local_irq_restore(flags);
+}
+
+/*
+ * 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_PAGE(PageCompound(page), page);
+        VM_BUG_ON_PAGE(!page_count(page), page);
+
+        for (i = 1; i < (1 << order); i++)
+                set_page_refcounted(page + i);
+        split_page_owner(page, 1 << order);
+        split_page_memcg(page, 1 << order);
+}
+EXPORT_SYMBOL_GPL(split_page);
+
+int __isolate_free_page(struct page *page, unsigned int order)
+{
+        unsigned long watermark;
+        struct zone *zone;
+        int mt;
+
+        BUG_ON(!PageBuddy(page));
+
+        zone = page_zone(page);
+        mt = get_pageblock_migratetype(page);
+
+        if (!is_migrate_isolate(mt)) {
+                /*
+                 * Obey watermarks as if the page was being allocated. We can
+                 * emulate a high-order watermark check with a raised order-0
+                 * watermark, because we already know our high-order page
+                 * exists.
+                 */
+                watermark = zone->_watermark[WMARK_MIN] + (1UL << order);
+                if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
+                        return 0;
+
+                __mod_zone_freepage_state(zone, -(1UL << order), mt);
+        }
+
+        /* Remove page from free list */
+
+        del_page_from_free_list(page, zone, order);
+
+        /*
+         * Set the pageblock if the isolated page is at least half of a
+         * pageblock
+         */
+        if (order >= pageblock_order - 1) {
+                struct page *endpage = page + (1 << order) - 1;
+                for (; page < endpage; page += pageblock_nr_pages) {
+                        int mt = get_pageblock_migratetype(page);
+                        if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
+                            && !is_migrate_highatomic(mt))
+                                set_pageblock_migratetype(page,
+                                                          MIGRATE_MOVABLE);
+                }
+        }
+
+
+        return 1UL << order;
+}
+
+/**
+ * __putback_isolated_page - Return a now-isolated page back where we got it
+ * @page: Page that was isolated
+ * @order: Order of the isolated page
+ * @mt: The page's pageblock's migratetype
+ *
+ * This function is meant to return a page pulled from the free lists via
+ * __isolate_free_page back to the free lists they were pulled from.
+ */
+void __putback_isolated_page(struct page *page, unsigned int order, int mt)
+{
+        struct zone *zone = page_zone(page);
+
+        /* zone lock should be held when this function is called */
+        lockdep_assert_held(&zone->lock);
+
+        /* Return isolated page to tail of freelist. */
+        __free_one_page(page, page_to_pfn(page), zone, order, mt,
+                        FPI_SKIP_REPORT_NOTIFY | FPI_TO_TAIL);
+}
+
+/*
+ * Update NUMA hit/miss statistics
+ *
+ * Must be called with interrupts disabled.
+ */
+static inline void zone_statistics(struct zone *preferred_zone, struct zone *z)
+{
+#ifdef CONFIG_NUMA
+        enum numa_stat_item local_stat = NUMA_LOCAL;
+
+        /* skip numa counters update if numa stats is disabled */
+        if (!static_branch_likely(&vm_numa_stat_key))
+                return;
+
+        if (zone_to_nid(z) != numa_node_id())
+                local_stat = NUMA_OTHER;
+
+        if (zone_to_nid(z) == zone_to_nid(preferred_zone))
+                __inc_numa_state(z, NUMA_HIT);
+        else {
+                __inc_numa_state(z, NUMA_MISS);
+                __inc_numa_state(preferred_zone, NUMA_FOREIGN);
+        }
+        __inc_numa_state(z, local_stat);
+#endif
+}
+
+/* Remove page from the per-cpu list, caller must protect the list */
+static struct page *__rmqueue_pcplist(struct zone *zone, int migratetype,
+                        unsigned int alloc_flags,
+                        struct per_cpu_pages *pcp,
+                        struct list_head *list)
+{
+        struct page *page;
+
+        do {
+                if (list_empty(list)) {
+                        pcp->count += rmqueue_bulk(zone, 0,
+                                        pcp->batch, list,
+                                        migratetype, alloc_flags);
+                        if (unlikely(list_empty(list)))
+                                return NULL;
+                }
+
+                page = list_first_entry(list, struct page, lru);
+                list_del(&page->lru);
+                pcp->count--;
+        } while (check_new_pcp(page));
+
+        return page;
+}
+
+/* Lock and remove page from the per-cpu list */
+static struct page *rmqueue_pcplist(struct zone *preferred_zone,
+                        struct zone *zone, gfp_t gfp_flags,
+                        int migratetype, unsigned int alloc_flags)
+{
+        struct per_cpu_pages *pcp;
+        struct list_head *list;
+        struct page *page;
+        unsigned long flags;
+
+        local_irq_save(flags);
+        pcp = &this_cpu_ptr(zone->pageset)->pcp;
+        list = &pcp->lists[migratetype];
+        page = __rmqueue_pcplist(zone,  migratetype, alloc_flags, pcp, list);
+        if (page) {
+                __count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
+                zone_statistics(preferred_zone, zone);
+        }
+        local_irq_restore(flags);
+        return page;
+}
+
+/*
+ * Allocate a page from the given zone. Use pcplists for order-0 allocations.
+ */
+static inline
+struct page *rmqueue(struct zone *preferred_zone,
+                        struct zone *zone, unsigned int order,
+                        gfp_t gfp_flags, unsigned int alloc_flags,
+                        int migratetype)
+{
+        unsigned long flags;
+        struct page *page;
+
+        if (likely(order == 0)) {
+                /*
+                 * MIGRATE_MOVABLE pcplist could have the pages on CMA area and
+                 * we need to skip it when CMA area isn't allowed.
+                 */
+                if (!IS_ENABLED(CONFIG_CMA) || alloc_flags & ALLOC_CMA ||
+                                migratetype != MIGRATE_MOVABLE ||
+                                IS_ENABLED(CONFIG_CMA_REUSE)) {
+                        page = rmqueue_pcplist(preferred_zone, zone, gfp_flags,
+                                        migratetype, alloc_flags);
+                        goto out;
+                }
+        }
+
+        /*
+         * We most definitely don't want callers attempting to
+         * allocate greater than order-1 page units with __GFP_NOFAIL.
+         */
+        WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
+        spin_lock_irqsave(&zone->lock, flags);
+
+        do {
+                page = NULL;
+                /*
+                 * order-0 request can reach here when the pcplist is skipped
+                 * due to non-CMA allocation context. HIGHATOMIC area is
+                 * reserved for high-order atomic allocation, so order-0
+                 * request should skip it.
+                 */
+                if (order > 0 && alloc_flags & ALLOC_HARDER) {
+                        page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
+                        if (page)
+                                trace_mm_page_alloc_zone_locked(page, order, migratetype);
+                }
+                if (!page)
+                        page = __rmqueue(zone, order, migratetype, alloc_flags);
+        } while (page && check_new_pages(page, order));
+        spin_unlock(&zone->lock);
+        if (!page)
+                goto failed;
+        __mod_zone_freepage_state(zone, -(1 << order),
+                                  get_pcppage_migratetype(page));
+
+        __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
+        zone_statistics(preferred_zone, zone);
+        local_irq_restore(flags);
+
+out:
+        /* Separate test+clear to avoid unnecessary atomics */
+        if (test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags)) {
+                clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
+                wakeup_kswapd(zone, 0, 0, zone_idx(zone));
+        }
+
+        VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
+        return page;
+
+failed:
+        local_irq_restore(flags);
+        return NULL;
+}
+
+#ifdef CONFIG_FAIL_PAGE_ALLOC
+
+static struct {
+        struct fault_attr attr;
+
+        bool ignore_gfp_highmem;
+        bool ignore_gfp_reclaim;
+        u32 min_order;
+} fail_page_alloc = {
+        .attr = FAULT_ATTR_INITIALIZER,
+        .ignore_gfp_reclaim = true,
+        .ignore_gfp_highmem = true,
+        .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 bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
+{
+        if (order < fail_page_alloc.min_order)
+                return false;
+        if (gfp_mask & __GFP_NOFAIL)
+                return false;
+        if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
+                return false;
+        if (fail_page_alloc.ignore_gfp_reclaim &&
+                        (gfp_mask & __GFP_DIRECT_RECLAIM))
+                return false;
+
+        return should_fail(&fail_page_alloc.attr, 1 << order);
+}
+
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+
+static int __init fail_page_alloc_debugfs(void)
+{
+        umode_t mode = S_IFREG | 0600;
+        struct dentry *dir;
+
+        dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
+                                        &fail_page_alloc.attr);
+
+        debugfs_create_bool("ignore-gfp-wait", mode, dir,
+                            &fail_page_alloc.ignore_gfp_reclaim);
+        debugfs_create_bool("ignore-gfp-highmem", mode, dir,
+                            &fail_page_alloc.ignore_gfp_highmem);
+        debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);
+
+        return 0;
+}
+
+late_initcall(fail_page_alloc_debugfs);
+
+#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
+
+#else /* CONFIG_FAIL_PAGE_ALLOC */
+
+static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
+{
+        return false;
+}
+
+#endif /* CONFIG_FAIL_PAGE_ALLOC */
+
+noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
+{
+        return __should_fail_alloc_page(gfp_mask, order);
+}
+ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);
+
+static inline long __zone_watermark_unusable_free(struct zone *z,
+                                unsigned int order, unsigned int alloc_flags)
+{
+        const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM));
+        long unusable_free = (1 << order) - 1;
+
+        /*
+         * If the caller does not have rights to ALLOC_HARDER then subtract
+         * the high-atomic reserves. This will over-estimate the size of the
+         * atomic reserve but it avoids a search.
+         */
+        if (likely(!alloc_harder))
+                unusable_free += z->nr_reserved_highatomic;
+
+#ifdef CONFIG_CMA
+        /* If allocation can't use CMA areas don't use free CMA pages */
+        if (!(alloc_flags & ALLOC_CMA))
+                unusable_free += zone_page_state(z, NR_FREE_CMA_PAGES);
+#endif
+
+        return unusable_free;
+}
+
+/*
+ * Return true if free base pages are above 'mark'. For high-order checks it
+ * will return true of the order-0 watermark is reached and there is at least
+ * one free page of a suitable size. Checking now avoids taking the zone lock
+ * to check in the allocation paths if no pages are free.
+ */
+bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
+                         int highest_zoneidx, unsigned int alloc_flags,
+                         long free_pages)
+{
+        long min = mark;
+        int o;
+        const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM));
+
+        /* free_pages may go negative - that's OK */
+        free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags);
+
+        if (alloc_flags & ALLOC_HIGH)
+                min -= min / 2;
+
+        if (unlikely(alloc_harder)) {
+                /*
+                 * OOM victims can try even harder than normal ALLOC_HARDER
+                 * users on the grounds that it's definitely going to be in
+                 * the exit path shortly and free memory. Any allocation it
+                 * makes during the free path will be small and short-lived.
+                 */
+                if (alloc_flags & ALLOC_OOM)
+                        min -= min / 2;
+                else
+                        min -= min / 4;
+        }
+
+        /*
+         * Check watermarks for an order-0 allocation request. If these
+         * are not met, then a high-order request also cannot go ahead
+         * even if a suitable page happened to be free.
+         */
+        if (free_pages <= min + z->lowmem_reserve[highest_zoneidx])
+                return false;
+
+        /* If this is an order-0 request then the watermark is fine */
+        if (!order)
+                return true;
+
+        /* For a high-order request, check at least one suitable page is free */
+        for (o = order; o < MAX_ORDER; o++) {
+                struct free_area *area = &z->free_area[o];
+                int mt;
+
+                if (!area->nr_free)
+                        continue;
+
+                for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
+                        if (!free_area_empty(area, mt))
+                                return true;
+                }
+
+#ifdef CONFIG_CMA
+                if ((alloc_flags & ALLOC_CMA) &&
+                    !free_area_empty(area, MIGRATE_CMA)) {
+                        return true;
+                }
+#endif
+                if (alloc_harder && !free_area_empty(area, MIGRATE_HIGHATOMIC))
+                        return true;
+        }
+        return false;
+}
+
+bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
+                      int highest_zoneidx, unsigned int alloc_flags)
+{
+        return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags,
+                                        zone_page_state(z, NR_FREE_PAGES));
+}
+
+static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
+                                unsigned long mark, int highest_zoneidx,
+                                unsigned int alloc_flags, gfp_t gfp_mask)
+{
+        long free_pages;
+
+        free_pages = zone_page_state(z, NR_FREE_PAGES);
+
+        /*
+         * Fast check for order-0 only. If this fails then the reserves
+         * need to be calculated.
+         */
+        if (!order) {
+                long usable_free;
+                long reserved;
+
+                usable_free = free_pages;
+                reserved = __zone_watermark_unusable_free(z, 0, alloc_flags);
+
+                /* reserved may over estimate high-atomic reserves. */
+                usable_free -= min(usable_free, reserved);
+                if (usable_free > mark + z->lowmem_reserve[highest_zoneidx])
+                        return true;
+        }
+
+        if (__zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags,
+                                        free_pages))
+                return true;
+        /*
+         * Ignore watermark boosting for GFP_ATOMIC order-0 allocations
+         * when checking the min watermark. The min watermark is the
+         * point where boosting is ignored so that kswapd is woken up
+         * when below the low watermark.
+         */
+        if (unlikely(!order && (gfp_mask & __GFP_ATOMIC) && z->watermark_boost
+                && ((alloc_flags & ALLOC_WMARK_MASK) == WMARK_MIN))) {
+                mark = z->_watermark[WMARK_MIN];
+                return __zone_watermark_ok(z, order, mark, highest_zoneidx,
+                                        alloc_flags, free_pages);
+        }
+
+        return false;
+}
+
+bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
+                        unsigned long mark, int highest_zoneidx)
+{
+        long free_pages = zone_page_state(z, NR_FREE_PAGES);
+
+        if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
+                free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
+
+        return __zone_watermark_ok(z, order, mark, highest_zoneidx, 0,
+                                                                free_pages);
+}
+
+#ifdef CONFIG_NUMA
+static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
+{
+        return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <=
+                                node_reclaim_distance;
+}
+#else   /* CONFIG_NUMA */
+static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
+{
+        return true;
+}
+#endif  /* CONFIG_NUMA */
+
+/*
+ * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid
+ * fragmentation is subtle. If the preferred zone was HIGHMEM then
+ * premature use of a lower zone may cause lowmem pressure problems that
+ * are worse than fragmentation. If the next zone is ZONE_DMA then it is
+ * probably too small. It only makes sense to spread allocations to avoid
+ * fragmentation between the Normal and DMA32 zones.
+ */
+static inline unsigned int
+alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
+{
+        unsigned int alloc_flags;
+
+        /*
+         * __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
+         * to save a branch.
+         */
+        alloc_flags = (__force int) (gfp_mask & __GFP_KSWAPD_RECLAIM);
+
+#ifdef CONFIG_ZONE_DMA32
+        if (!zone)
+                return alloc_flags;
+
+        if (zone_idx(zone) != ZONE_NORMAL)
+                return alloc_flags;
+
+        /*
+         * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and
+         * the pointer is within zone->zone_pgdat->node_zones[]. Also assume
+         * on UMA that if Normal is populated then so is DMA32.
+         */
+        BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1);
+        if (nr_online_nodes > 1 && !populated_zone(--zone))
+                return alloc_flags;
+
+        alloc_flags |= ALLOC_NOFRAGMENT;
+#endif /* CONFIG_ZONE_DMA32 */
+        return alloc_flags;
+}
+
+static inline unsigned int current_alloc_flags(gfp_t gfp_mask,
+                                        unsigned int alloc_flags)
+{
+#ifdef CONFIG_CMA
+        unsigned int pflags = current->flags;
+
+        if (!(pflags & PF_MEMALLOC_NOCMA) &&
+                        gfp_migratetype(gfp_mask) == get_cma_migratetype())
+                alloc_flags |= ALLOC_CMA;
+
+#endif
+        return alloc_flags;
+}
+
+/*
+ * get_page_from_freelist goes through the zonelist trying to allocate
+ * a page.
+ */
+static struct page *
+get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
+                                                const struct alloc_context *ac)
+{
+        struct zoneref *z;
+        struct zone *zone;
+        struct pglist_data *last_pgdat_dirty_limit = NULL;
+        bool no_fallback;
+
+retry:
+        /*
+         * Scan zonelist, looking for a zone with enough free.
+         * See also __cpuset_node_allowed() comment in kernel/cpuset.c.
+         */
+        no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
+        z = ac->preferred_zoneref;
+        for_next_zone_zonelist_nodemask(zone, z, ac->highest_zoneidx,
+                                        ac->nodemask) {
+                struct page *page;
+                unsigned long mark;
+
+                if (cpusets_enabled() &&
+                        (alloc_flags & ALLOC_CPUSET) &&
+                        !__cpuset_zone_allowed(zone, gfp_mask))
+                                continue;
+                /*
+                 * When allocating a page cache page for writing, we
+                 * want to get it from a node that is within its dirty
+                 * limit, such that no single node holds more than its
+                 * proportional share of globally allowed dirty pages.
+                 * The dirty limits take into account the node's
+                 * lowmem reserves and high watermark so that kswapd
+                 * should be able to balance it without having to
+                 * write pages from its LRU list.
+                 *
+                 * XXX: For now, allow allocations to potentially
+                 * exceed the per-node dirty limit in the slowpath
+                 * (spread_dirty_pages unset) before going into reclaim,
+                 * which is important when on a NUMA setup the allowed
+                 * nodes are together not big enough to reach the
+                 * global limit.  The proper fix for these situations
+                 * will require awareness of nodes in the
+                 * dirty-throttling and the flusher threads.
+                 */
+                if (ac->spread_dirty_pages) {
+                        if (last_pgdat_dirty_limit == zone->zone_pgdat)
+                                continue;
+
+                        if (!node_dirty_ok(zone->zone_pgdat)) {
+                                last_pgdat_dirty_limit = zone->zone_pgdat;
+                                continue;
+                        }
+                }
+
+                if (no_fallback && nr_online_nodes > 1 &&
+                    zone != ac->preferred_zoneref->zone) {
+                        int local_nid;
+
+                        /*
+                         * If moving to a remote node, retry but allow
+                         * fragmenting fallbacks. Locality is more important
+                         * than fragmentation avoidance.
+                         */
+                        local_nid = zone_to_nid(ac->preferred_zoneref->zone);
+                        if (zone_to_nid(zone) != local_nid) {
+                                alloc_flags &= ~ALLOC_NOFRAGMENT;
+                                goto retry;
+                        }
+                }
+
+                mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
+                if (!zone_watermark_fast(zone, order, mark,
+                                       ac->highest_zoneidx, alloc_flags,
+                                       gfp_mask)) {
+                        int ret;
+
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+                        /*
+                         * Watermark failed for this zone, but see if we can
+                         * grow this zone if it contains deferred pages.
+                         */
+                        if (static_branch_unlikely(&deferred_pages)) {
+                                if (_deferred_grow_zone(zone, order))
+                                        goto try_this_zone;
+                        }
+#endif
+                        /* Checked here to keep the fast path fast */
+                        BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
+                        if (alloc_flags & ALLOC_NO_WATERMARKS)
+                                goto try_this_zone;
+
+                        if (node_reclaim_mode == 0 ||
+                            !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
+                                continue;
+
+                        ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
+                        switch (ret) {
+                        case NODE_RECLAIM_NOSCAN:
+                                /* did not scan */
+                                continue;
+                        case NODE_RECLAIM_FULL:
+                                /* scanned but unreclaimable */
+                                continue;
+                        default:
+                                /* did we reclaim enough */
+                                if (zone_watermark_ok(zone, order, mark,
+                                        ac->highest_zoneidx, alloc_flags))
+                                        goto try_this_zone;
+
+                                continue;
+                        }
+                }
+
+try_this_zone:
+                page = rmqueue(ac->preferred_zoneref->zone, zone, order,
+                                gfp_mask, alloc_flags, ac->migratetype);
+                if (page) {
+                        prep_new_page(page, order, gfp_mask, alloc_flags);
+
+                        /*
+                         * If this is a high-order atomic allocation then check
+                         * if the pageblock should be reserved for the future
+                         */
+                        if (unlikely(order && (alloc_flags & ALLOC_HARDER)))
+                                reserve_highatomic_pageblock(page, zone, order);
+
+                        return page;
+                } else {
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+                        /* Try again if zone has deferred pages */
+                        if (static_branch_unlikely(&deferred_pages)) {
+                                if (_deferred_grow_zone(zone, order))
+                                        goto try_this_zone;
+                        }
+#endif
+                }
+        }
+
+        /*
+         * It's possible on a UMA machine to get through all zones that are
+         * fragmented. If avoiding fragmentation, reset and try again.
+         */
+        if (no_fallback) {
+                alloc_flags &= ~ALLOC_NOFRAGMENT;
+                goto retry;
+        }
+
+        return NULL;
+}
+
+static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask)
+{
+        unsigned int filter = SHOW_MEM_FILTER_NODES;
+
+        /*
+         * This documents exceptions given to allocations in certain
+         * contexts that are allowed to allocate outside current's set
+         * of allowed nodes.
+         */
+        if (!(gfp_mask & __GFP_NOMEMALLOC))
+                if (tsk_is_oom_victim(current) ||
+                    (current->flags & (PF_MEMALLOC | PF_EXITING)))
+                        filter &= ~SHOW_MEM_FILTER_NODES;
+        if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
+                filter &= ~SHOW_MEM_FILTER_NODES;
+
+        show_mem(filter, nodemask);
+}
+
+void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)
+{
+        struct va_format vaf;
+        va_list args;
+        static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1);
+
+        if ((gfp_mask & __GFP_NOWARN) ||
+             !__ratelimit(&nopage_rs) ||
+             ((gfp_mask & __GFP_DMA) && !has_managed_dma()))
+                return;
+
+        va_start(args, fmt);
+        vaf.fmt = fmt;
+        vaf.va = &args;
+        pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl",
+                        current->comm, &vaf, gfp_mask, &gfp_mask,
+                        nodemask_pr_args(nodemask));
+        va_end(args);
+
+        cpuset_print_current_mems_allowed();
+        pr_cont("\n");
+        dump_stack();
+        warn_alloc_show_mem(gfp_mask, nodemask);
+}
+
+static inline struct page *
+__alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order,
+                              unsigned int alloc_flags,
+                              const struct alloc_context *ac)
+{
+        struct page *page;
+
+        page = get_page_from_freelist(gfp_mask, order,
+                        alloc_flags|ALLOC_CPUSET, ac);
+        /*
+         * fallback to ignore cpuset restriction if our nodes
+         * are depleted
+         */
+        if (!page)
+                page = get_page_from_freelist(gfp_mask, order,
+                                alloc_flags, ac);
+
+        return page;
+}
+
+static inline struct page *
+__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
+        const struct alloc_context *ac, unsigned long *did_some_progress)
+{
+        struct oom_control oc = {
+                .zonelist = ac->zonelist,
+                .nodemask = ac->nodemask,
+                .memcg = NULL,
+                .gfp_mask = gfp_mask,
+                .order = order,
+        };
+        struct page *page;
+
+        *did_some_progress = 0;
+
+        /*
+         * Acquire the oom lock.  If that fails, somebody else is
+         * making progress for us.
+         */
+        if (!mutex_trylock(&oom_lock)) {
+                *did_some_progress = 1;
+                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. But make sure that this reclaim
+         * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY
+         * allocation which will never fail due to oom_lock already held.
+         */
+        page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) &
+                                      ~__GFP_DIRECT_RECLAIM, order,
+                                      ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
+        if (page)
+                goto out;
+
+        /* Coredumps can quickly deplete all memory reserves */
+        if (current->flags & PF_DUMPCORE)
+                goto out;
+        /* The OOM killer will not help higher order allocs */
+        if (order > PAGE_ALLOC_COSTLY_ORDER)
+                goto out;
+        /*
+         * We have already exhausted all our reclaim opportunities without any
+         * success so it is time to admit defeat. We will skip the OOM killer
+         * because it is very likely that the caller has a more reasonable
+         * fallback than shooting a random task.
+         *
+         * The OOM killer may not free memory on a specific node.
+         */
+        if (gfp_mask & (__GFP_RETRY_MAYFAIL | __GFP_THISNODE))
+                goto out;
+        /* The OOM killer does not needlessly kill tasks for lowmem */
+        if (ac->highest_zoneidx < ZONE_NORMAL)
+                goto out;
+        if (pm_suspended_storage())
+                goto out;
+        /*
+         * XXX: GFP_NOFS allocations should rather fail than rely on
+         * other request to make a forward progress.
+         * We are in an unfortunate situation where out_of_memory cannot
+         * do much for this context but let's try it to at least get
+         * access to memory reserved if the current task is killed (see
+         * out_of_memory). Once filesystems are ready to handle allocation
+         * failures more gracefully we should just bail out here.
+         */
+
+        /* Exhausted what can be done so it's blame time */
+        if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
+                *did_some_progress = 1;
+
+                /*
+                 * Help non-failing allocations by giving them access to memory
+                 * reserves
+                 */
+                if (gfp_mask & __GFP_NOFAIL)
+                        page = __alloc_pages_cpuset_fallback(gfp_mask, order,
+                                        ALLOC_NO_WATERMARKS, ac);
+        }
+out:
+        mutex_unlock(&oom_lock);
+        return page;
+}
+
+/*
+ * Maximum number of compaction retries wit a progress before OOM
+ * killer is consider as the only way to move forward.
+ */
+#define MAX_COMPACT_RETRIES 16
+
+#ifdef CONFIG_COMPACTION
+/* Try memory compaction for high-order allocations before reclaim */
+static struct page *
+__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
+                unsigned int alloc_flags, const struct alloc_context *ac,
+                enum compact_priority prio, enum compact_result *compact_result)
+{
+        struct page *page = NULL;
+        unsigned long pflags;
+        unsigned int noreclaim_flag;
+
+        if (!order)
+                return NULL;
+
+        psi_memstall_enter(&pflags);
+        noreclaim_flag = memalloc_noreclaim_save();
+
+        *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
+                                                                prio, &page);
+
+        memalloc_noreclaim_restore(noreclaim_flag);
+        psi_memstall_leave(&pflags);
+
+        /*
+         * At least in one zone compaction wasn't deferred or skipped, so let's
+         * count a compaction stall
+         */
+        count_vm_event(COMPACTSTALL);
+
+        /* Prep a captured page if available */
+        if (page)
+                prep_new_page(page, order, gfp_mask, alloc_flags);
+
+        /* Try get a page from the freelist if available */
+        if (!page)
+                page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
+
+        if (page) {
+                struct zone *zone = page_zone(page);
+
+                zone->compact_blockskip_flush = false;
+                compaction_defer_reset(zone, order, true);
+                count_vm_event(COMPACTSUCCESS);
+                return page;
+        }
+
+        /*
+         * It's bad if compaction run occurs and fails. The most likely reason
+         * is that pages exist, but not enough to satisfy watermarks.
+         */
+        count_vm_event(COMPACTFAIL);
+
+        cond_resched();
+
+        return NULL;
+}
+
+static inline bool
+should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
+                     enum compact_result compact_result,
+                     enum compact_priority *compact_priority,
+                     int *compaction_retries)
+{
+        int max_retries = MAX_COMPACT_RETRIES;
+        int min_priority;
+        bool ret = false;
+        int retries = *compaction_retries;
+        enum compact_priority priority = *compact_priority;
+
+        if (!order)
+                return false;
+
+        if (compaction_made_progress(compact_result))
+                (*compaction_retries)++;
+
+        /*
+         * compaction considers all the zone as desperately out of memory
+         * so it doesn't really make much sense to retry except when the
+         * failure could be caused by insufficient priority
+         */
+        if (compaction_failed(compact_result))
+                goto check_priority;
+
+        /*
+         * compaction was skipped because there are not enough order-0 pages
+         * to work with, so we retry only if it looks like reclaim can help.
+         */
+        if (compaction_needs_reclaim(compact_result)) {
+                ret = compaction_zonelist_suitable(ac, order, alloc_flags);
+                goto out;
+        }
+
+        /*
+         * make sure the compaction wasn't deferred or didn't bail out early
+         * due to locks contention before we declare that we should give up.
+         * But the next retry should use a higher priority if allowed, so
+         * we don't just keep bailing out endlessly.
+         */
+        if (compaction_withdrawn(compact_result)) {
+                goto check_priority;
+        }
+
+        /*
+         * !costly requests are much more important than __GFP_RETRY_MAYFAIL
+         * costly ones because they are de facto nofail and invoke OOM
+         * killer to move on while costly can fail and users are ready
+         * to cope with that. 1/4 retries is rather arbitrary but we
+         * would need much more detailed feedback from compaction to
+         * make a better decision.
+         */
+        if (order > PAGE_ALLOC_COSTLY_ORDER)
+                max_retries /= 4;
+        if (*compaction_retries <= max_retries) {
+                ret = true;
+                goto out;
+        }
+
+        /*
+         * Make sure there are attempts at the highest priority if we exhausted
+         * all retries or failed at the lower priorities.
+         */
+check_priority:
+        min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ?
+                        MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;
+
+        if (*compact_priority > min_priority) {
+                (*compact_priority)--;
+                *compaction_retries = 0;
+                ret = true;
+        }
+out:
+        trace_compact_retry(order, priority, compact_result, retries, max_retries, ret);
+        return ret;
+}
+#else
+static inline struct page *
+__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
+                unsigned int alloc_flags, const struct alloc_context *ac,
+                enum compact_priority prio, enum compact_result *compact_result)
+{
+        *compact_result = COMPACT_SKIPPED;
+        return NULL;
+}
+
+static inline bool
+should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
+                     enum compact_result compact_result,
+                     enum compact_priority *compact_priority,
+                     int *compaction_retries)
+{
+        struct zone *zone;
+        struct zoneref *z;
+
+        if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
+                return false;
+
+        /*
+         * There are setups with compaction disabled which would prefer to loop
+         * inside the allocator rather than hit the oom killer prematurely.
+         * Let's give them a good hope and keep retrying while the order-0
+         * watermarks are OK.
+         */
+        for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
+                                ac->highest_zoneidx, ac->nodemask) {
+                if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
+                                        ac->highest_zoneidx, alloc_flags))
+                        return true;
+        }
+        return false;
+}
+#endif /* CONFIG_COMPACTION */
+
+#ifdef CONFIG_LOCKDEP
+static struct lockdep_map __fs_reclaim_map =
+        STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map);
+
+static bool __need_fs_reclaim(gfp_t gfp_mask)
+{
+        gfp_mask = current_gfp_context(gfp_mask);
+
+        /* no reclaim without waiting on it */
+        if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
+                return false;
+
+        /* this guy won't enter reclaim */
+        if (current->flags & PF_MEMALLOC)
+                return false;
+
+        /* We're only interested __GFP_FS allocations for now */
+        if (!(gfp_mask & __GFP_FS))
+                return false;
+
+        if (gfp_mask & __GFP_NOLOCKDEP)
+                return false;
+
+        return true;
+}
+
+void __fs_reclaim_acquire(void)
+{
+        lock_map_acquire(&__fs_reclaim_map);
+}
+
+void __fs_reclaim_release(void)
+{
+        lock_map_release(&__fs_reclaim_map);
+}
+
+void fs_reclaim_acquire(gfp_t gfp_mask)
+{
+        if (__need_fs_reclaim(gfp_mask))
+                __fs_reclaim_acquire();
+}
+EXPORT_SYMBOL_GPL(fs_reclaim_acquire);
+
+void fs_reclaim_release(gfp_t gfp_mask)
+{
+        if (__need_fs_reclaim(gfp_mask))
+                __fs_reclaim_release();
+}
+EXPORT_SYMBOL_GPL(fs_reclaim_release);
+#endif
+
+/*
+ * Zonelists may change due to hotplug during allocation. Detect when zonelists
+ * have been rebuilt so allocation retries. Reader side does not lock and
+ * retries the allocation if zonelist changes. Writer side is protected by the
+ * embedded spin_lock.
+ */
+static DEFINE_SEQLOCK(zonelist_update_seq);
+
+static unsigned int zonelist_iter_begin(void)
+{
+        if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
+                return read_seqbegin(&zonelist_update_seq);
+
+        return 0;
+}
+
+static unsigned int check_retry_zonelist(unsigned int seq)
+{
+        if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
+                return read_seqretry(&zonelist_update_seq, seq);
+
+        return seq;
+}
+
+/* Perform direct synchronous page reclaim */
+static unsigned long
+__perform_reclaim(gfp_t gfp_mask, unsigned int order,
+                                        const struct alloc_context *ac)
+{
+        unsigned int noreclaim_flag;
+        unsigned long pflags, progress;
+
+        cond_resched();
+
+        /* We now go into synchronous reclaim */
+        cpuset_memory_pressure_bump();
+        psi_memstall_enter(&pflags);
+        fs_reclaim_acquire(gfp_mask);
+        noreclaim_flag = memalloc_noreclaim_save();
+
+        progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
+                                                                ac->nodemask);
+
+        memalloc_noreclaim_restore(noreclaim_flag);
+        fs_reclaim_release(gfp_mask);
+        psi_memstall_leave(&pflags);
+
+        cond_resched();
+
+        return progress;
+}
+
+/* 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,
+                unsigned int alloc_flags, const struct alloc_context *ac,
+                unsigned long *did_some_progress)
+{
+        struct page *page = NULL;
+        bool drained = false;
+
+        *did_some_progress = __perform_reclaim(gfp_mask, order, ac);
+        if (unlikely(!(*did_some_progress)))
+                return NULL;
+
+retry:
+        page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
+
+        /*
+         * If an allocation failed after direct reclaim, it could be because
+         * pages are pinned on the per-cpu lists or in high alloc reserves.
+         * Shrink them and try again
+         */
+        if (!page && !drained) {
+                unreserve_highatomic_pageblock(ac, false);
+#ifdef CONFIG_RECLAIM_ACCT
+                reclaimacct_substage_start(RA_DRAINALLPAGES);
+#endif
+                drain_all_pages(NULL);
+#ifdef CONFIG_RECLAIM_ACCT
+                reclaimacct_substage_end(RA_DRAINALLPAGES, 0, NULL);
+#endif
+                drained = true;
+                goto retry;
+        }
+
+        return page;
+}
+
+static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
+                             const struct alloc_context *ac)
+{
+        struct zoneref *z;
+        struct zone *zone;
+        pg_data_t *last_pgdat = NULL;
+        enum zone_type highest_zoneidx = ac->highest_zoneidx;
+
+        for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx,
+                                        ac->nodemask) {
+                if (last_pgdat != zone->zone_pgdat)
+                        wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx);
+                last_pgdat = zone->zone_pgdat;
+        }
+}
+
+static inline unsigned int
+gfp_to_alloc_flags(gfp_t gfp_mask)
+{
+        unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
+
+        /*
+         * __GFP_HIGH is assumed to be the same as ALLOC_HIGH
+         * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
+         * to save two branches.
+         */
+        BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
+        BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD);
+
+        /*
+         * 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 (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
+         */
+        alloc_flags |= (__force int)
+                (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM));
+
+        if (gfp_mask & __GFP_ATOMIC) {
+                /*
+                 * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
+                 * if it can't schedule.
+                 */
+                if (!(gfp_mask & __GFP_NOMEMALLOC))
+                        alloc_flags |= ALLOC_HARDER;
+                /*
+                 * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
+                 * comment for __cpuset_node_allowed().
+                 */
+                alloc_flags &= ~ALLOC_CPUSET;
+        } else if (unlikely(rt_task(current)) && !in_interrupt())
+                alloc_flags |= ALLOC_HARDER;
+
+        alloc_flags = current_alloc_flags(gfp_mask, alloc_flags);
+
+        return alloc_flags;
+}
+
+static bool oom_reserves_allowed(struct task_struct *tsk)
+{
+        if (!tsk_is_oom_victim(tsk))
+                return false;
+
+        /*
+         * !MMU doesn't have oom reaper so give access to memory reserves
+         * only to the thread with TIF_MEMDIE set
+         */
+        if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE))
+                return false;
+
+        return true;
+}
+
+/*
+ * Distinguish requests which really need access to full memory
+ * reserves from oom victims which can live with a portion of it
+ */
+static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask)
+{
+        if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
+                return 0;
+        if (gfp_mask & __GFP_MEMALLOC)
+                return ALLOC_NO_WATERMARKS;
+        if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
+                return ALLOC_NO_WATERMARKS;
+        if (!in_interrupt()) {
+                if (current->flags & PF_MEMALLOC)
+                        return ALLOC_NO_WATERMARKS;
+                else if (oom_reserves_allowed(current))
+                        return ALLOC_OOM;
+        }
+
+        return 0;
+}
+
+bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
+{
+        return !!__gfp_pfmemalloc_flags(gfp_mask);
+}
+
+/*
+ * Checks whether it makes sense to retry the reclaim to make a forward progress
+ * for the given allocation request.
+ *
+ * We give up when we either have tried MAX_RECLAIM_RETRIES in a row
+ * without success, or when we couldn't even meet the watermark if we
+ * reclaimed all remaining pages on the LRU lists.
+ *
+ * Returns true if a retry is viable or false to enter the oom path.
+ */
+static inline bool
+should_reclaim_retry(gfp_t gfp_mask, unsigned order,
+                     struct alloc_context *ac, int alloc_flags,
+                     bool did_some_progress, int *no_progress_loops)
+{
+        struct zone *zone;
+        struct zoneref *z;
+        bool ret = false;
+
+        /*
+         * Costly allocations might have made a progress but this doesn't mean
+         * their order will become available due to high fragmentation so
+         * always increment the no progress counter for them
+         */
+        if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
+                *no_progress_loops = 0;
+        else
+                (*no_progress_loops)++;
+
+        /*
+         * Make sure we converge to OOM if we cannot make any progress
+         * several times in the row.
+         */
+        if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
+                /* Before OOM, exhaust highatomic_reserve */
+                return unreserve_highatomic_pageblock(ac, true);
+        }
+
+        /*
+         * Keep reclaiming pages while there is a chance this will lead
+         * somewhere.  If none of the target zones can satisfy our allocation
+         * request even if all reclaimable pages are considered then we are
+         * screwed and have to go OOM.
+         */
+        for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
+                                ac->highest_zoneidx, ac->nodemask) {
+                unsigned long available;
+                unsigned long reclaimable;
+                unsigned long min_wmark = min_wmark_pages(zone);
+                bool wmark;
+
+                available = reclaimable = zone_reclaimable_pages(zone);
+                available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
+
+                /*
+                 * Would the allocation succeed if we reclaimed all
+                 * reclaimable pages?
+                 */
+                wmark = __zone_watermark_ok(zone, order, min_wmark,
+                                ac->highest_zoneidx, alloc_flags, available);
+                trace_reclaim_retry_zone(z, order, reclaimable,
+                                available, min_wmark, *no_progress_loops, wmark);
+                if (wmark) {
+                        /*
+                         * If we didn't make any progress and have a lot of
+                         * dirty + writeback pages then we should wait for
+                         * an IO to complete to slow down the reclaim and
+                         * prevent from pre mature OOM
+                         */
+                        if (!did_some_progress) {
+                                unsigned long write_pending;
+
+                                write_pending = zone_page_state_snapshot(zone,
+                                                        NR_ZONE_WRITE_PENDING);
+
+                                if (2 * write_pending > reclaimable) {
+                                        congestion_wait(BLK_RW_ASYNC, HZ/10);
+                                        return true;
+                                }
+                        }
+
+                        ret = true;
+                        goto out;
+                }
+        }
+
+out:
+        /*
+         * Memory allocation/reclaim might be called from a WQ context and the
+         * current implementation of the WQ concurrency control doesn't
+         * recognize that a particular WQ is congested if the worker thread is
+         * looping without ever sleeping. Therefore we have to do a short sleep
+         * here rather than calling cond_resched().
+         */
+        if (current->flags & PF_WQ_WORKER)
+                schedule_timeout_uninterruptible(1);
+        else
+                cond_resched();
+        return ret;
+}
+
+static inline bool
+check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac)
+{
+        /*
+         * It's possible that cpuset's mems_allowed and the nodemask from
+         * mempolicy don't intersect. This should be normally dealt with by
+         * policy_nodemask(), but it's possible to race with cpuset update in
+         * such a way the check therein was true, and then it became false
+         * before we got our cpuset_mems_cookie here.
+         * This assumes that for all allocations, ac->nodemask can come only
+         * from MPOL_BIND mempolicy (whose documented semantics is to be ignored
+         * when it does not intersect with the cpuset restrictions) or the
+         * caller can deal with a violated nodemask.
+         */
+        if (cpusets_enabled() && ac->nodemask &&
+                        !cpuset_nodemask_valid_mems_allowed(ac->nodemask)) {
+                ac->nodemask = NULL;
+                return true;
+        }
+
+        /*
+         * When updating a task's mems_allowed or mempolicy nodemask, it is
+         * possible to race with parallel threads in such a way that our
+         * allocation can fail while the mask is being updated. If we are about
+         * to fail, check if the cpuset changed during allocation and if so,
+         * retry.
+         */
+        if (read_mems_allowed_retry(cpuset_mems_cookie))
+                return true;
+
+        return false;
+}
+
+static inline struct page *
+__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
+                                                struct alloc_context *ac)
+{
+        bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
+        const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER;
+        struct page *page = NULL;
+        unsigned int alloc_flags;
+        unsigned long did_some_progress;
+        enum compact_priority compact_priority;
+        enum compact_result compact_result;
+        int compaction_retries;
+        int no_progress_loops;
+        unsigned int cpuset_mems_cookie;
+        unsigned int zonelist_iter_cookie;
+        int reserve_flags;
+#ifdef CONFIG_RECLAIM_ACCT
+        struct reclaim_acct ra = {0};
+#endif
+
+        /*
+         * We also sanity check to catch abuse of atomic reserves being used by
+         * callers that are not in atomic context.
+         */
+        if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) ==
+                                (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
+                gfp_mask &= ~__GFP_ATOMIC;
+
+restart:
+        compaction_retries = 0;
+        no_progress_loops = 0;
+        compact_priority = DEF_COMPACT_PRIORITY;
+        cpuset_mems_cookie = read_mems_allowed_begin();
+        zonelist_iter_cookie = zonelist_iter_begin();
+
+        /*
+         * The fast path uses conservative alloc_flags to succeed only until
+         * kswapd needs to be woken up, and to avoid the cost of setting up
+         * alloc_flags precisely. So we do that now.
+         */
+        alloc_flags = gfp_to_alloc_flags(gfp_mask);
+
+        /*
+         * We need to recalculate the starting point for the zonelist iterator
+         * because we might have used different nodemask in the fast path, or
+         * there was a cpuset modification and we are retrying - otherwise we
+         * could end up iterating over non-eligible zones endlessly.
+         */
+        ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
+                                        ac->highest_zoneidx, ac->nodemask);
+        if (!ac->preferred_zoneref->zone)
+                goto nopage;
+
+        if (alloc_flags & ALLOC_KSWAPD)
+                wake_all_kswapds(order, gfp_mask, ac);
+
+        /*
+         * The adjusted alloc_flags might result in immediate success, so try
+         * that first
+         */
+        page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
+        if (page)
+                goto got_pg;
+
+        /*
+         * For costly allocations, try direct compaction first, as it's likely
+         * that we have enough base pages and don't need to reclaim. For non-
+         * movable high-order allocations, do that as well, as compaction will
+         * try prevent permanent fragmentation by migrating from blocks of the
+         * same migratetype.
+         * Don't try this for allocations that are allowed to ignore
+         * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen.
+         */
+        if (can_direct_reclaim &&
+                        (costly_order ||
+                           (order > 0 && ac->migratetype != MIGRATE_MOVABLE))
+                        && !gfp_pfmemalloc_allowed(gfp_mask)) {
+                page = __alloc_pages_direct_compact(gfp_mask, order,
+                                                alloc_flags, ac,
+                                                INIT_COMPACT_PRIORITY,
+                                                &compact_result);
+                if (page)
+                        goto got_pg;
+
+                /*
+                 * Checks for costly allocations with __GFP_NORETRY, which
+                 * includes some THP page fault allocations
+                 */
+                if (costly_order && (gfp_mask & __GFP_NORETRY)) {
+                        /*
+                         * If allocating entire pageblock(s) and compaction
+                         * failed because all zones are below low watermarks
+                         * or is prohibited because it recently failed at this
+                         * order, fail immediately unless the allocator has
+                         * requested compaction and reclaim retry.
+                         *
+                         * Reclaim is
+                         *  - potentially very expensive because zones are far
+                         *    below their low watermarks or this is part of very
+                         *    bursty high order allocations,
+                         *  - not guaranteed to help because isolate_freepages()
+                         *    may not iterate over freed pages as part of its
+                         *    linear scan, and
+                         *  - unlikely to make entire pageblocks free on its
+                         *    own.
+                         */
+                        if (compact_result == COMPACT_SKIPPED ||
+                            compact_result == COMPACT_DEFERRED)
+                                goto nopage;
+
+                        /*
+                         * Looks like reclaim/compaction is worth trying, but
+                         * sync compaction could be very expensive, so keep
+                         * using async compaction.
+                         */
+                        compact_priority = INIT_COMPACT_PRIORITY;
+                }
+        }
+
+retry:
+        /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
+        if (alloc_flags & ALLOC_KSWAPD)
+                wake_all_kswapds(order, gfp_mask, ac);
+
+        reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
+        if (reserve_flags)
+                alloc_flags = current_alloc_flags(gfp_mask, reserve_flags);
+
+        /*
+         * Reset the nodemask and zonelist iterators if memory policies can be
+         * ignored. These allocations are high priority and system rather than
+         * user oriented.
+         */
+        if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) {
+                ac->nodemask = NULL;
+                ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
+                                        ac->highest_zoneidx, ac->nodemask);
+        }
+
+        /* Attempt with potentially adjusted zonelist and alloc_flags */
+        page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
+        if (page)
+                goto got_pg;
+
+        /* Caller is not willing to reclaim, we can't balance anything */
+        if (!can_direct_reclaim)
+                goto nopage;
+
+        /* Avoid recursion of direct reclaim */
+        if (current->flags & PF_MEMALLOC)
+                goto nopage;
+
+        /* Try direct reclaim and then allocating */
+#ifdef CONFIG_RECLAIM_ACCT
+        reclaimacct_start(DIRECT_RECLAIMS, &ra);
+#endif
+        page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
+                                                        &did_some_progress);
+#ifdef CONFIG_RECLAIM_ACCT
+        reclaimacct_end(DIRECT_RECLAIMS);
+#endif
+        if (page)
+                goto got_pg;
+
+        /* Try direct compaction and then allocating */
+        page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
+                                        compact_priority, &compact_result);
+        if (page)
+                goto got_pg;
+
+        /* Do not loop if specifically requested */
+        if (gfp_mask & __GFP_NORETRY)
+                goto nopage;
+
+        /*
+         * Do not retry costly high order allocations unless they are
+         * __GFP_RETRY_MAYFAIL
+         */
+        if (costly_order && !(gfp_mask & __GFP_RETRY_MAYFAIL))
+                goto nopage;
+
+        if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
+                                 did_some_progress > 0, &no_progress_loops))
+                goto retry;
+
+        /*
+         * It doesn't make any sense to retry for the compaction if the order-0
+         * reclaim is not able to make any progress because the current
+         * implementation of the compaction depends on the sufficient amount
+         * of free memory (see __compaction_suitable)
+         */
+        if (did_some_progress > 0 &&
+                        should_compact_retry(ac, order, alloc_flags,
+                                compact_result, &compact_priority,
+                                &compaction_retries))
+                goto retry;
+
+
+        /*
+         * Deal with possible cpuset update races or zonelist updates to avoid
+         * a unnecessary OOM kill.
+         */
+        if (check_retry_cpuset(cpuset_mems_cookie, ac) ||
+            check_retry_zonelist(zonelist_iter_cookie))
+                goto restart;
+
+        /* Reclaim has failed us, start killing things */
+        page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
+        if (page)
+                goto got_pg;
+
+        /* Avoid allocations with no watermarks from looping endlessly */
+        if (tsk_is_oom_victim(current) &&
+            (alloc_flags & ALLOC_OOM ||
+             (gfp_mask & __GFP_NOMEMALLOC)))
+                goto nopage;
+
+        /* Retry as long as the OOM killer is making progress */
+        if (did_some_progress) {
+                no_progress_loops = 0;
+                goto retry;
+        }
+
+nopage:
+        /*
+         * Deal with possible cpuset update races or zonelist updates to avoid
+         * a unnecessary OOM kill.
+         */
+        if (check_retry_cpuset(cpuset_mems_cookie, ac) ||
+            check_retry_zonelist(zonelist_iter_cookie))
+                goto restart;
+
+        /*
+         * Make sure that __GFP_NOFAIL request doesn't leak out and make sure
+         * we always retry
+         */
+        if (gfp_mask & __GFP_NOFAIL) {
+                /*
+                 * All existing users of the __GFP_NOFAIL are blockable, so warn
+                 * of any new users that actually require GFP_NOWAIT
+                 */
+                if (WARN_ON_ONCE(!can_direct_reclaim))
+                        goto fail;
+
+                /*
+                 * PF_MEMALLOC request from this context is rather bizarre
+                 * because we cannot reclaim anything and only can loop waiting
+                 * for somebody to do a work for us
+                 */
+                WARN_ON_ONCE(current->flags & PF_MEMALLOC);
+
+                /*
+                 * non failing costly orders are a hard requirement which we
+                 * are not prepared for much so let's warn about these users
+                 * so that we can identify them and convert them to something
+                 * else.
+                 */
+                WARN_ON_ONCE(order > PAGE_ALLOC_COSTLY_ORDER);
+
+                /*
+                 * Help non-failing allocations by giving them access to memory
+                 * reserves but do not use ALLOC_NO_WATERMARKS because this
+                 * could deplete whole memory reserves which would just make
+                 * the situation worse
+                 */
+                page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_HARDER, ac);
+                if (page)
+                        goto got_pg;
+
+                cond_resched();
+                goto retry;
+        }
+fail:
+        warn_alloc(gfp_mask, ac->nodemask,
+                        "page allocation failure: order:%u", order);
+got_pg:
+        return page;
+}
+
+static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
+                int preferred_nid, nodemask_t *nodemask,
+                struct alloc_context *ac, gfp_t *alloc_mask,
+                unsigned int *alloc_flags)
+{
+        ac->highest_zoneidx = gfp_zone(gfp_mask);
+        ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
+        ac->nodemask = nodemask;
+        ac->migratetype = gfp_migratetype(gfp_mask);
+
+        if (cpusets_enabled()) {
+                *alloc_mask |= __GFP_HARDWALL;
+                /*
+                 * When we are in the interrupt context, it is irrelevant
+                 * to the current task context. It means that any node ok.
+                 */
+                if (!in_interrupt() && !ac->nodemask)
+                        ac->nodemask = &cpuset_current_mems_allowed;
+                else
+                        *alloc_flags |= ALLOC_CPUSET;
+        }
+
+        fs_reclaim_acquire(gfp_mask);
+        fs_reclaim_release(gfp_mask);
+
+        might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
+
+#ifdef CONFIG_HYPERHOLD_ZSWAPD
+        if (gfp_mask & __GFP_KSWAPD_RECLAIM)
+                wake_all_zswapd();
+#endif
+
+        if (should_fail_alloc_page(gfp_mask, order))
+                return false;
+
+        *alloc_flags = current_alloc_flags(gfp_mask, *alloc_flags);
+
+        /* Dirty zone balancing only done in the fast path */
+        ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
+
+        /*
+         * The preferred zone is used for statistics but crucially it is
+         * also used as the starting point for the zonelist iterator. It
+         * may get reset for allocations that ignore memory policies.
+         */
+        ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
+                                        ac->highest_zoneidx, ac->nodemask);
+
+        return true;
+}
+
+/*
+ * This is the 'heart' of the zoned buddy allocator.
+ */
+struct page *
+__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
+                                                        nodemask_t *nodemask)
+{
+        struct page *page;
+        unsigned int alloc_flags = ALLOC_WMARK_LOW;
+        gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */
+        struct alloc_context ac = { };
+
+        /*
+         * There are several places where we assume that the order value is sane
+         * so bail out early if the request is out of bound.
+         */
+        if (unlikely(order >= MAX_ORDER)) {
+                WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
+                return NULL;
+        }
+
+        gfp_mask &= gfp_allowed_mask;
+        alloc_mask = gfp_mask;
+        if (!prepare_alloc_pages(gfp_mask, order, preferred_nid, nodemask, &ac, &alloc_mask, &alloc_flags))
+                return NULL;
+
+        /*
+         * Forbid the first pass from falling back to types that fragment
+         * memory until all local zones are considered.
+         */
+        alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp_mask);
+
+        /* First allocation attempt */
+        page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
+        if (likely(page))
+                goto out;
+
+        /*
+         * Apply scoped allocation constraints. This is mainly about GFP_NOFS
+         * resp. GFP_NOIO which has to be inherited for all allocation requests
+         * from a particular context which has been marked by
+         * memalloc_no{fs,io}_{save,restore}.
+         */
+        alloc_mask = current_gfp_context(gfp_mask);
+        ac.spread_dirty_pages = false;
+
+        /*
+         * Restore the original nodemask if it was potentially replaced with
+         * &cpuset_current_mems_allowed to optimize the fast-path attempt.
+         */
+        ac.nodemask = nodemask;
+
+        page = __alloc_pages_slowpath(alloc_mask, order, &ac);
+
+out:
+        if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
+            unlikely(__memcg_kmem_charge_page(page, gfp_mask, order) != 0)) {
+                __free_pages(page, order);
+                page = NULL;
+        }
+
+        trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);
+
+        return page;
+}
+EXPORT_SYMBOL(__alloc_pages_nodemask);
+
+/*
+ * Common helper functions. Never use with __GFP_HIGHMEM because the returned
+ * address cannot represent highmem pages. Use alloc_pages and then kmap if
+ * you need to access high mem.
+ */
+unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
+{
+        struct page *page;
+
+        page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, 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)
+{
+        return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
+}
+EXPORT_SYMBOL(get_zeroed_page);
+
+static inline void free_the_page(struct page *page, unsigned int order)
+{
+        if (order == 0)         /* Via pcp? */
+                free_unref_page(page);
+        else
+                __free_pages_ok(page, order, FPI_NONE);
+}
+
+void __free_pages(struct page *page, unsigned int order)
+{
+        if (put_page_testzero(page))
+                free_the_page(page, order);
+        else if (!PageHead(page))
+                while (order-- > 0)
+                        free_the_page(page + (1 << order), 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);
+
+/*
+ * Page Fragment:
+ *  An arbitrary-length arbitrary-offset area of memory which resides
+ *  within a 0 or higher order page.  Multiple fragments within that page
+ *  are individually refcounted, in the page's reference counter.
+ *
+ * The page_frag functions below provide a simple allocation framework for
+ * page fragments.  This is used by the network stack and network device
+ * drivers to provide a backing region of memory for use as either an
+ * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
+ */
+static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
+                                             gfp_t gfp_mask)
+{
+        struct page *page = NULL;
+        gfp_t gfp = gfp_mask;
+
+#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
+        gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
+                    __GFP_NOMEMALLOC;
+        page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
+                                PAGE_FRAG_CACHE_MAX_ORDER);
+        nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
+#endif
+        if (unlikely(!page))
+                page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
+
+        nc->va = page ? page_address(page) : NULL;
+
+#ifdef CONFIG_PAGE_TRACING
+        if (likely(page)) {
+                int order = get_order(nc->size);
+                int i;
+                struct page *newpage = page;
+                unsigned int deta = 1U << (unsigned int)order;
+
+                for (i = 0; i < (1 << order); i++) {
+                        if (!newpage)
+                                break;
+                        SetPageSKB(newpage);
+                        newpage++;
+                }
+                mod_zone_page_state(page_zone(page), NR_SKB_PAGES, (long)deta);
+        }
+#endif
+
+        return page;
+}
+
+void __page_frag_cache_drain(struct page *page, unsigned int count)
+{
+        VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
+
+        if (page_ref_sub_and_test(page, count)) {
+#ifdef CONFIG_PAGE_TRACING
+                if (likely(page)) {
+                        unsigned int deta = 1U << compound_order(page);
+
+                        mod_zone_page_state(page_zone(page), NR_SKB_PAGES, -(long)deta);
+                }
+#endif
+                free_the_page(page, compound_order(page));
+        }
+}
+EXPORT_SYMBOL(__page_frag_cache_drain);
+
+void *page_frag_alloc(struct page_frag_cache *nc,
+                      unsigned int fragsz, gfp_t gfp_mask)
+{
+        unsigned int size = PAGE_SIZE;
+        struct page *page;
+        int offset;
+
+        if (unlikely(!nc->va)) {
+refill:
+                page = __page_frag_cache_refill(nc, gfp_mask);
+                if (!page)
+                        return NULL;
+
+#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
+                /* if size can vary use size else just use PAGE_SIZE */
+                size = nc->size;
+#endif
+                /* Even if we own the page, we do not use atomic_set().
+                 * This would break get_page_unless_zero() users.
+                 */
+                page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE);
+
+                /* reset page count bias and offset to start of new frag */
+                nc->pfmemalloc = page_is_pfmemalloc(page);
+                nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
+                nc->offset = size;
+        }
+
+        offset = nc->offset - fragsz;
+        if (unlikely(offset < 0)) {
+                page = virt_to_page(nc->va);
+
+                if (!page_ref_sub_and_test(page, nc->pagecnt_bias))
+                        goto refill;
+
+                if (unlikely(nc->pfmemalloc)) {
+                        free_the_page(page, compound_order(page));
+                        goto refill;
+                }
+
+#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
+                /* if size can vary use size else just use PAGE_SIZE */
+                size = nc->size;
+#endif
+                /* OK, page count is 0, we can safely set it */
+                set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1);
+
+                /* reset page count bias and offset to start of new frag */
+                nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
+                offset = size - fragsz;
+                if (unlikely(offset < 0)) {
+                        /*
+                         * The caller is trying to allocate a fragment
+                         * with fragsz > PAGE_SIZE but the cache isn't big
+                         * enough to satisfy the request, this may
+                         * happen in low memory conditions.
+                         * We don't release the cache page because
+                         * it could make memory pressure worse
+                         * so we simply return NULL here.
+                         */
+                        return NULL;
+                }
+        }
+
+        nc->pagecnt_bias--;
+        nc->offset = offset;
+
+        return nc->va + offset;
+}
+EXPORT_SYMBOL(page_frag_alloc);
+
+/*
+ * Frees a page fragment allocated out of either a compound or order 0 page.
+ */
+void page_frag_free(void *addr)
+{
+        struct page *page = virt_to_head_page(addr);
+
+        if (unlikely(put_page_testzero(page))) {
+#ifdef CONFIG_PAGE_TRACING
+                if (likely(page)) {
+                        unsigned int deta = 1U << compound_order(page);
+
+                        mod_zone_page_state(page_zone(page), NR_SKB_PAGES, -(long)deta);
+                }
+#endif
+                free_the_page(page, compound_order(page));
+        }
+}
+EXPORT_SYMBOL(page_frag_free);
+
+static void *make_alloc_exact(unsigned long addr, unsigned int order,
+                size_t size)
+{
+        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;
+}
+
+/**
+ * alloc_pages_exact - allocate an exact number physically-contiguous pages.
+ * @size: the number of bytes to allocate
+ * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
+ *
+ * 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().
+ *
+ * Return: pointer to the allocated area or %NULL in case of error.
+ */
+void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
+{
+        unsigned int order = get_order(size);
+        unsigned long addr;
+
+        if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
+                gfp_mask &= ~__GFP_COMP;
+
+        addr = __get_free_pages(gfp_mask, order);
+        return make_alloc_exact(addr, order, size);
+}
+EXPORT_SYMBOL(alloc_pages_exact);
+
+/**
+ * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
+ *                         pages on a node.
+ * @nid: the preferred node ID where memory should be allocated
+ * @size: the number of bytes to allocate
+ * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
+ *
+ * Like alloc_pages_exact(), but try to allocate on node nid first before falling
+ * back.
+ *
+ * Return: pointer to the allocated area or %NULL in case of error.
+ */
+void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
+{
+        unsigned int order = get_order(size);
+        struct page *p;
+
+        if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
+                gfp_mask &= ~__GFP_COMP;
+
+        p = alloc_pages_node(nid, gfp_mask, order);
+        if (!p)
+                return NULL;
+        return make_alloc_exact((unsigned long)page_address(p), order, size);
+}
+
+/**
+ * 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);
+
+/**
+ * nr_free_zone_pages - count number of pages beyond high watermark
+ * @offset: The zone index of the highest zone
+ *
+ * nr_free_zone_pages() counts the number of pages which are beyond the
+ * high watermark within all zones at or below a given zone index.  For each
+ * zone, the number of pages is calculated as:
+ *
+ *     nr_free_zone_pages = managed_pages - high_pages
+ *
+ * Return: number of pages beyond high watermark.
+ */
+static unsigned long nr_free_zone_pages(int offset)
+{
+        struct zoneref *z;
+        struct zone *zone;
+
+        /* Just pick one node, since fallback list is circular */
+        unsigned long sum = 0;
+
+        struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
+
+        for_each_zone_zonelist(zone, z, zonelist, offset) {
+                unsigned long size = zone_managed_pages(zone);
+                unsigned long high = high_wmark_pages(zone);
+                if (size > high)
+                        sum += size - high;
+        }
+
+        return sum;
+}
+
+/**
+ * nr_free_buffer_pages - count number of pages beyond high watermark
+ *
+ * nr_free_buffer_pages() counts the number of pages which are beyond the high
+ * watermark within ZONE_DMA and ZONE_NORMAL.
+ *
+ * Return: number of pages beyond high watermark within ZONE_DMA and
+ * ZONE_NORMAL.
+ */
+unsigned long nr_free_buffer_pages(void)
+{
+        return nr_free_zone_pages(gfp_zone(GFP_USER));
+}
+EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
+
+static inline void show_node(struct zone *zone)
+{
+        if (IS_ENABLED(CONFIG_NUMA))
+                printk("Node %d ", zone_to_nid(zone));
+}
+
+long si_mem_available(void)
+{
+        long available;
+        unsigned long pagecache;
+        unsigned long wmark_low = 0;
+        unsigned long pages[NR_LRU_LISTS];
+        unsigned long reclaimable;
+        struct zone *zone;
+        int lru;
+
+        for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
+                pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
+
+        for_each_zone(zone)
+                wmark_low += low_wmark_pages(zone);
+
+        /*
+         * Estimate the amount of memory available for userspace allocations,
+         * without causing swapping.
+         */
+        available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages;
+
+        /*
+         * Not all the page cache can be freed, otherwise the system will
+         * start swapping. Assume at least half of the page cache, or the
+         * low watermark worth of cache, needs to stay.
+         */
+        pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
+        pagecache -= min(pagecache / 2, wmark_low);
+        available += pagecache;
+
+        /*
+         * Part of the reclaimable slab and other kernel memory consists of
+         * items that are in use, and cannot be freed. Cap this estimate at the
+         * low watermark.
+         */
+        reclaimable = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B) +
+                global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
+        available += reclaimable - min(reclaimable / 2, wmark_low);
+
+        if (available < 0)
+                available = 0;
+        return available;
+}
+EXPORT_SYMBOL_GPL(si_mem_available);
+
+void si_meminfo(struct sysinfo *val)
+{
+        val->totalram = totalram_pages();
+        val->sharedram = global_node_page_state(NR_SHMEM);
+        val->freeram = global_zone_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)
+{
+        int zone_type;          /* needs to be signed */
+        unsigned long managed_pages = 0;
+        unsigned long managed_highpages = 0;
+        unsigned long free_highpages = 0;
+        pg_data_t *pgdat = NODE_DATA(nid);
+
+        for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
+                managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]);
+        val->totalram = managed_pages;
+        val->sharedram = node_page_state(pgdat, NR_SHMEM);
+        val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
+#ifdef CONFIG_HIGHMEM
+        for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
+                struct zone *zone = &pgdat->node_zones[zone_type];
+
+                if (is_highmem(zone)) {
+                        managed_highpages += zone_managed_pages(zone);
+                        free_highpages += zone_page_state(zone, NR_FREE_PAGES);
+                }
+        }
+        val->totalhigh = managed_highpages;
+        val->freehigh = free_highpages;
+#else
+        val->totalhigh = managed_highpages;
+        val->freehigh = free_highpages;
+#endif
+        val->mem_unit = PAGE_SIZE;
+}
+#endif
+
+/*
+ * Determine whether the node should be displayed or not, depending on whether
+ * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
+ */
+static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask)
+{
+        if (!(flags & SHOW_MEM_FILTER_NODES))
+                return false;
+
+        /*
+         * no node mask - aka implicit memory numa policy. Do not bother with
+         * the synchronization - read_mems_allowed_begin - because we do not
+         * have to be precise here.
+         */
+        if (!nodemask)
+                nodemask = &cpuset_current_mems_allowed;
+
+        return !node_isset(nid, *nodemask);
+}
+
+#define K(x) ((x) << (PAGE_SHIFT-10))
+
+static void show_migration_types(unsigned char type)
+{
+        static const char types[MIGRATE_TYPES] = {
+                [MIGRATE_UNMOVABLE]     = 'U',
+                [MIGRATE_MOVABLE]       = 'M',
+                [MIGRATE_RECLAIMABLE]   = 'E',
+                [MIGRATE_HIGHATOMIC]    = 'H',
+#ifdef CONFIG_CMA
+                [MIGRATE_CMA]           = 'C',
+#endif
+#ifdef CONFIG_MEMORY_ISOLATION
+                [MIGRATE_ISOLATE]       = 'I',
+#endif
+        };
+        char tmp[MIGRATE_TYPES + 1];
+        char *p = tmp;
+        int i;
+
+        for (i = 0; i < MIGRATE_TYPES; i++) {
+                if (type & (1 << i))
+                        *p++ = types[i];
+        }
+
+        *p = '\0';
+        printk(KERN_CONT "(%s) ", tmp);
+}
+
+/*
+ * 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.
+ *
+ * Bits in @filter:
+ * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
+ *   cpuset.
+ */
+void show_free_areas(unsigned int filter, nodemask_t *nodemask)
+{
+        unsigned long free_pcp = 0;
+        int cpu;
+        struct zone *zone;
+        pg_data_t *pgdat;
+
+        for_each_populated_zone(zone) {
+                if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
+                        continue;
+
+                for_each_online_cpu(cpu)
+                        free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
+        }
+
+        printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
+                " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
+                " unevictable:%lu dirty:%lu writeback:%lu\n"
+                " slab_reclaimable:%lu slab_unreclaimable:%lu\n"
+                " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
+                " free:%lu free_pcp:%lu free_cma:%lu\n",
+                global_node_page_state(NR_ACTIVE_ANON),
+                global_node_page_state(NR_INACTIVE_ANON),
+                global_node_page_state(NR_ISOLATED_ANON),
+                global_node_page_state(NR_ACTIVE_FILE),
+                global_node_page_state(NR_INACTIVE_FILE),
+                global_node_page_state(NR_ISOLATED_FILE),
+                global_node_page_state(NR_UNEVICTABLE),
+                global_node_page_state(NR_FILE_DIRTY),
+                global_node_page_state(NR_WRITEBACK),
+                global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B),
+                global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B),
+                global_node_page_state(NR_FILE_MAPPED),
+                global_node_page_state(NR_SHMEM),
+                global_zone_page_state(NR_PAGETABLE),
+                global_zone_page_state(NR_BOUNCE),
+                global_zone_page_state(NR_FREE_PAGES),
+                free_pcp,
+                global_zone_page_state(NR_FREE_CMA_PAGES));
+
+        for_each_online_pgdat(pgdat) {
+                if (show_mem_node_skip(filter, pgdat->node_id, nodemask))
+                        continue;
+
+                printk("Node %d"
+                        " active_anon:%lukB"
+                        " inactive_anon:%lukB"
+                        " active_file:%lukB"
+                        " inactive_file:%lukB"
+                        " unevictable:%lukB"
+                        " isolated(anon):%lukB"
+                        " isolated(file):%lukB"
+                        " mapped:%lukB"
+                        " dirty:%lukB"
+                        " writeback:%lukB"
+                        " shmem:%lukB"
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+                        " shmem_thp: %lukB"
+                        " shmem_pmdmapped: %lukB"
+                        " anon_thp: %lukB"
+#endif
+                        " writeback_tmp:%lukB"
+                        " kernel_stack:%lukB"
+#ifdef CONFIG_SHADOW_CALL_STACK
+                        " shadow_call_stack:%lukB"
+#endif
+                        " all_unreclaimable? %s"
+                        "\n",
+                        pgdat->node_id,
+                        K(node_page_state(pgdat, NR_ACTIVE_ANON)),
+                        K(node_page_state(pgdat, NR_INACTIVE_ANON)),
+                        K(node_page_state(pgdat, NR_ACTIVE_FILE)),
+                        K(node_page_state(pgdat, NR_INACTIVE_FILE)),
+                        K(node_page_state(pgdat, NR_UNEVICTABLE)),
+                        K(node_page_state(pgdat, NR_ISOLATED_ANON)),
+                        K(node_page_state(pgdat, NR_ISOLATED_FILE)),
+                        K(node_page_state(pgdat, NR_FILE_MAPPED)),
+                        K(node_page_state(pgdat, NR_FILE_DIRTY)),
+                        K(node_page_state(pgdat, NR_WRITEBACK)),
+                        K(node_page_state(pgdat, NR_SHMEM)),
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+                        K(node_page_state(pgdat, NR_SHMEM_THPS) * HPAGE_PMD_NR),
+                        K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)
+                                        * HPAGE_PMD_NR),
+                        K(node_page_state(pgdat, NR_ANON_THPS) * HPAGE_PMD_NR),
+#endif
+                        K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
+                        node_page_state(pgdat, NR_KERNEL_STACK_KB),
+#ifdef CONFIG_SHADOW_CALL_STACK
+                        node_page_state(pgdat, NR_KERNEL_SCS_KB),
+#endif
+                        pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ?
+                                "yes" : "no");
+        }
+
+        for_each_populated_zone(zone) {
+                int i;
+
+                if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
+                        continue;
+
+                free_pcp = 0;
+                for_each_online_cpu(cpu)
+                        free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
+
+                show_node(zone);
+                printk(KERN_CONT
+                        "%s"
+                        " free:%lukB"
+                        " min:%lukB"
+                        " low:%lukB"
+                        " high:%lukB"
+                        " reserved_highatomic:%luKB"
+                        " active_anon:%lukB"
+                        " inactive_anon:%lukB"
+                        " active_file:%lukB"
+                        " inactive_file:%lukB"
+                        " unevictable:%lukB"
+                        " writepending:%lukB"
+                        " present:%lukB"
+                        " managed:%lukB"
+                        " mlocked:%lukB"
+                        " pagetables:%lukB"
+                        " bounce:%lukB"
+                        " free_pcp:%lukB"
+                        " local_pcp:%ukB"
+                        " free_cma:%lukB"
+                        "\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->nr_reserved_highatomic),
+                        K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)),
+                        K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)),
+                        K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
+                        K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
+                        K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
+                        K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
+                        K(zone->present_pages),
+                        K(zone_managed_pages(zone)),
+                        K(zone_page_state(zone, NR_MLOCK)),
+                        K(zone_page_state(zone, NR_PAGETABLE)),
+                        K(zone_page_state(zone, NR_BOUNCE)),
+                        K(free_pcp),
+                        K(this_cpu_read(zone->pageset->pcp.count)),
+                        K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
+                printk("lowmem_reserve[]:");
+                for (i = 0; i < MAX_NR_ZONES; i++)
+                        printk(KERN_CONT " %ld", zone->lowmem_reserve[i]);
+                printk(KERN_CONT "\n");
+        }
+
+        for_each_populated_zone(zone) {
+                unsigned int order;
+                unsigned long nr[MAX_ORDER], flags, total = 0;
+                unsigned char types[MAX_ORDER];
+
+                if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
+                        continue;
+                show_node(zone);
+                printk(KERN_CONT "%s: ", zone->name);
+
+                spin_lock_irqsave(&zone->lock, flags);
+                for (order = 0; order < MAX_ORDER; order++) {
+                        struct free_area *area = &zone->free_area[order];
+                        int type;
+
+                        nr[order] = area->nr_free;
+                        total += nr[order] << order;
+
+                        types[order] = 0;
+                        for (type = 0; type < MIGRATE_TYPES; type++) {
+                                if (!free_area_empty(area, type))
+                                        types[order] |= 1 << type;
+                        }
+                }
+                spin_unlock_irqrestore(&zone->lock, flags);
+                for (order = 0; order < MAX_ORDER; order++) {
+                        printk(KERN_CONT "%lu*%lukB ",
+                               nr[order], K(1UL) << order);
+                        if (nr[order])
+                                show_migration_types(types[order]);
+                }
+                printk(KERN_CONT "= %lukB\n", K(total));
+        }
+
+        hugetlb_show_meminfo();
+
+        printk("%ld total pagecache pages\n", global_node_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_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs)
+{
+        struct zone *zone;
+        enum zone_type zone_type = MAX_NR_ZONES;
+        int nr_zones = 0;
+
+        do {
+                zone_type--;
+                zone = pgdat->node_zones + zone_type;
+                if (populated_zone(zone)) {
+                        zoneref_set_zone(zone, &zonerefs[nr_zones++]);
+                        check_highest_zone(zone_type);
+                }
+        } while (zone_type);
+
+        return nr_zones;
+}
+
+#ifdef CONFIG_NUMA
+
+static int __parse_numa_zonelist_order(char *s)
+{
+        /*
+         * We used to support different zonlists modes but they turned
+         * out to be just not useful. Let's keep the warning in place
+         * if somebody still use the cmd line parameter so that we do
+         * not fail it silently
+         */
+        if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) {
+                pr_warn("Ignoring unsupported numa_zonelist_order value:  %s\n", s);
+                return -EINVAL;
+        }
+        return 0;
+}
+
+char numa_zonelist_order[] = "Node";
+
+/*
+ * sysctl handler for numa_zonelist_order
+ */
+int numa_zonelist_order_handler(struct ctl_table *table, int write,
+                void *buffer, size_t *length, loff_t *ppos)
+{
+        if (write)
+                return __parse_numa_zonelist_order(buffer);
+        return proc_dostring(table, write, buffer, length, ppos);
+}
+
+
+#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.
+ *
+ * Return: node id of the found node or %NUMA_NO_NODE 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 = NUMA_NO_NODE;
+
+        /* 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_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 */
+                if (!cpumask_empty(cpumask_of_node(n)))
+                        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_order,
+                unsigned nr_nodes)
+{
+        struct zoneref *zonerefs;
+        int i;
+
+        zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
+
+        for (i = 0; i < nr_nodes; i++) {
+                int nr_zones;
+
+                pg_data_t *node = NODE_DATA(node_order[i]);
+
+                nr_zones = build_zonerefs_node(node, zonerefs);
+                zonerefs += nr_zones;
+        }
+        zonerefs->zone = NULL;
+        zonerefs->zone_idx = 0;
+}
+
+/*
+ * Build gfp_thisnode zonelists
+ */
+static void build_thisnode_zonelists(pg_data_t *pgdat)
+{
+        struct zoneref *zonerefs;
+        int nr_zones;
+
+        zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs;
+        nr_zones = build_zonerefs_node(pgdat, zonerefs);
+        zonerefs += nr_zones;
+        zonerefs->zone = NULL;
+        zonerefs->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 void build_zonelists(pg_data_t *pgdat)
+{
+        static int node_order[MAX_NUMNODES];
+        int node, load, nr_nodes = 0;
+        nodemask_t used_mask = NODE_MASK_NONE;
+        int local_node, prev_node;
+
+        /* NUMA-aware ordering of nodes */
+        local_node = pgdat->node_id;
+        load = nr_online_nodes;
+        prev_node = local_node;
+
+        memset(node_order, 0, sizeof(node_order));
+        while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
+                /*
+                 * 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 (node_distance(local_node, node) !=
+                    node_distance(local_node, prev_node))
+                        node_load[node] = load;
+
+                node_order[nr_nodes++] = node;
+                prev_node = node;
+                load--;
+        }
+
+        build_zonelists_in_node_order(pgdat, node_order, nr_nodes);
+        build_thisnode_zonelists(pgdat);
+}
+
+#ifdef CONFIG_HAVE_MEMORYLESS_NODES
+/*
+ * Return node id of node used for "local" allocations.
+ * I.e., first node id of first zone in arg node's generic zonelist.
+ * Used for initializing percpu 'numa_mem', which is used primarily
+ * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
+ */
+int local_memory_node(int node)
+{
+        struct zoneref *z;
+
+        z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
+                                   gfp_zone(GFP_KERNEL),
+                                   NULL);
+        return zone_to_nid(z->zone);
+}
+#endif
+
+static void setup_min_unmapped_ratio(void);
+static void setup_min_slab_ratio(void);
+#else   /* CONFIG_NUMA */
+
+static void build_zonelists(pg_data_t *pgdat)
+{
+        int node, local_node;
+        struct zoneref *zonerefs;
+        int nr_zones;
+
+        local_node = pgdat->node_id;
+
+        zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
+        nr_zones = build_zonerefs_node(pgdat, zonerefs);
+        zonerefs += nr_zones;
+
+        /*
+         * 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;
+                nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
+                zonerefs += nr_zones;
+        }
+        for (node = 0; node < local_node; node++) {
+                if (!node_online(node))
+                        continue;
+                nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
+                zonerefs += nr_zones;
+        }
+
+        zonerefs->zone = NULL;
+        zonerefs->zone_idx = 0;
+}
+
+#endif  /* 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.
+ *
+ * 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 void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
+static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
+static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
+
+static void __build_all_zonelists(void *data)
+{
+        int nid;
+        int __maybe_unused cpu;
+        pg_data_t *self = data;
+
+        write_seqlock(&zonelist_update_seq);
+
+#ifdef CONFIG_NUMA
+        memset(node_load, 0, sizeof(node_load));
+#endif
+
+        /*
+         * This node is hotadded and no memory is yet present.   So just
+         * building zonelists is fine - no need to touch other nodes.
+         */
+        if (self && !node_online(self->node_id)) {
+                build_zonelists(self);
+        } else {
+                for_each_online_node(nid) {
+                        pg_data_t *pgdat = NODE_DATA(nid);
+
+                        build_zonelists(pgdat);
+                }
+
+#ifdef CONFIG_HAVE_MEMORYLESS_NODES
+                /*
+                 * We now know the "local memory node" for each node--
+                 * i.e., the node of the first zone in the generic zonelist.
+                 * Set up numa_mem percpu variable for on-line cpus.  During
+                 * boot, only the boot cpu should be on-line;  we'll init the
+                 * secondary cpus' numa_mem as they come on-line.  During
+                 * node/memory hotplug, we'll fixup all on-line cpus.
+                 */
+                for_each_online_cpu(cpu)
+                        set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
+#endif
+        }
+
+        write_sequnlock(&zonelist_update_seq);
+}
+
+static noinline void __init
+build_all_zonelists_init(void)
+{
+        int cpu;
+
+        __build_all_zonelists(NULL);
+
+        /*
+         * Initialize the boot_pagesets that are going to be used
+         * for bootstrapping processors. The real pagesets for
+         * each zone will be allocated later when the per cpu
+         * allocator is available.
+         *
+         * boot_pagesets are used also for bootstrapping offline
+         * cpus if the system is already booted because the pagesets
+         * are needed to initialize allocators on a specific cpu too.
+         * F.e. the percpu allocator needs the page allocator which
+         * needs the percpu allocator in order to allocate its pagesets
+         * (a chicken-egg dilemma).
+         */
+        for_each_possible_cpu(cpu)
+                setup_pageset(&per_cpu(boot_pageset, cpu), 0);
+
+        mminit_verify_zonelist();
+        cpuset_init_current_mems_allowed();
+}
+
+/*
+ * unless system_state == SYSTEM_BOOTING.
+ *
+ * __ref due to call of __init annotated helper build_all_zonelists_init
+ * [protected by SYSTEM_BOOTING].
+ */
+void __ref build_all_zonelists(pg_data_t *pgdat)
+{
+        unsigned long vm_total_pages;
+
+        if (system_state == SYSTEM_BOOTING) {
+                build_all_zonelists_init();
+        } else {
+                __build_all_zonelists(pgdat);
+                /* cpuset refresh routine should be here */
+        }
+        /* Get the number of free pages beyond high watermark in all zones. */
+        vm_total_pages = nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
+        /*
+         * 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;
+
+        pr_info("Built %u zonelists, mobility grouping %s.  Total pages: %ld\n",
+                nr_online_nodes,
+                page_group_by_mobility_disabled ? "off" : "on",
+                vm_total_pages);
+#ifdef CONFIG_NUMA
+        pr_info("Policy zone: %s\n", zone_names[policy_zone]);
+#endif
+}
+
+/* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
+static bool __meminit
+overlap_memmap_init(unsigned long zone, unsigned long *pfn)
+{
+        static struct memblock_region *r;
+
+        if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
+                if (!r || *pfn >= memblock_region_memory_end_pfn(r)) {
+                        for_each_mem_region(r) {
+                                if (*pfn < memblock_region_memory_end_pfn(r))
+                                        break;
+                        }
+                }
+                if (*pfn >= memblock_region_memory_base_pfn(r) &&
+                    memblock_is_mirror(r)) {
+                        *pfn = memblock_region_memory_end_pfn(r);
+                        return true;
+                }
+        }
+        return false;
+}
+
+/*
+ * Initially all pages are reserved - free ones are freed
+ * up by memblock_free_all() once the early boot process is
+ * done. Non-atomic initialization, single-pass.
+ *
+ * All aligned pageblocks are initialized to the specified migratetype
+ * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
+ * zone stats (e.g., nr_isolate_pageblock) are touched.
+ */
+void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
+                unsigned long start_pfn, unsigned long zone_end_pfn,
+                enum meminit_context context,
+                struct vmem_altmap *altmap, int migratetype)
+{
+        unsigned long pfn, end_pfn = start_pfn + size;
+        struct page *page;
+
+        if (highest_memmap_pfn < end_pfn - 1)
+                highest_memmap_pfn = end_pfn - 1;
+
+#ifdef CONFIG_ZONE_DEVICE
+        /*
+         * Honor reservation requested by the driver for this ZONE_DEVICE
+         * memory. We limit the total number of pages to initialize to just
+         * those that might contain the memory mapping. We will defer the
+         * ZONE_DEVICE page initialization until after we have released
+         * the hotplug lock.
+         */
+        if (zone == ZONE_DEVICE) {
+                if (!altmap)
+                        return;
+
+                if (start_pfn == altmap->base_pfn)
+                        start_pfn += altmap->reserve;
+                end_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
+        }
+#endif
+
+        for (pfn = start_pfn; pfn < end_pfn; ) {
+                /*
+                 * There can be holes in boot-time mem_map[]s handed to this
+                 * function.  They do not exist on hotplugged memory.
+                 */
+                if (context == MEMINIT_EARLY) {
+                        if (overlap_memmap_init(zone, &pfn))
+                                continue;
+                        if (defer_init(nid, pfn, zone_end_pfn))
+                                break;
+                }
+
+                page = pfn_to_page(pfn);
+                __init_single_page(page, pfn, zone, nid);
+                if (context == MEMINIT_HOTPLUG)
+                        __SetPageReserved(page);
+
+                /*
+                 * Usually, we want to mark the pageblock MIGRATE_MOVABLE,
+                 * such that unmovable allocations won't be scattered all
+                 * over the place during system boot.
+                 */
+                if (IS_ALIGNED(pfn, pageblock_nr_pages)) {
+                        set_pageblock_migratetype(page, migratetype);
+                        cond_resched();
+                }
+                pfn++;
+        }
+}
+
+#ifdef CONFIG_ZONE_DEVICE
+void __ref memmap_init_zone_device(struct zone *zone,
+                                   unsigned long start_pfn,
+                                   unsigned long nr_pages,
+                                   struct dev_pagemap *pgmap)
+{
+        unsigned long pfn, end_pfn = start_pfn + nr_pages;
+        struct pglist_data *pgdat = zone->zone_pgdat;
+        struct vmem_altmap *altmap = pgmap_altmap(pgmap);
+        unsigned long zone_idx = zone_idx(zone);
+        unsigned long start = jiffies;
+        int nid = pgdat->node_id;
+
+        if (WARN_ON_ONCE(!pgmap || zone_idx(zone) != ZONE_DEVICE))
+                return;
+
+        /*
+         * The call to memmap_init should have already taken care
+         * of the pages reserved for the memmap, so we can just jump to
+         * the end of that region and start processing the device pages.
+         */
+        if (altmap) {
+                start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
+                nr_pages = end_pfn - start_pfn;
+        }
+
+        for (pfn = start_pfn; pfn < end_pfn; pfn++) {
+                struct page *page = pfn_to_page(pfn);
+
+                __init_single_page(page, pfn, zone_idx, nid);
+
+                /*
+                 * Mark page reserved as it will need to wait for onlining
+                 * phase for it to be fully associated with a zone.
+                 *
+                 * We can use the non-atomic __set_bit operation for setting
+                 * the flag as we are still initializing the pages.
+                 */
+                __SetPageReserved(page);
+
+                /*
+                 * ZONE_DEVICE pages union ->lru with a ->pgmap back pointer
+                 * and zone_device_data.  It is a bug if a ZONE_DEVICE page is
+                 * ever freed or placed on a driver-private list.
+                 */
+                page->pgmap = pgmap;
+                page->zone_device_data = NULL;
+
+                /*
+                 * 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.
+                 *
+                 * Please note that MEMINIT_HOTPLUG path doesn't clear memmap
+                 * because this is done early in section_activate()
+                 */
+                if (IS_ALIGNED(pfn, pageblock_nr_pages)) {
+                        set_pageblock_migratetype(page, MIGRATE_MOVABLE);
+                        cond_resched();
+                }
+        }
+
+        pr_info("%s initialised %lu pages in %ums\n", __func__,
+                nr_pages, jiffies_to_msecs(jiffies - start));
+}
+
+#endif
+static void __meminit zone_init_free_lists(struct zone *zone)
+{
+        unsigned 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;
+        }
+}
+
+#if !defined(CONFIG_FLAT_NODE_MEM_MAP)
+/*
+ * Only struct pages that correspond to ranges defined by memblock.memory
+ * are zeroed and initialized by going through __init_single_page() during
+ * memmap_init_zone_range().
+ *
+ * But, there could be struct pages that correspond to holes in
+ * memblock.memory. This can happen because of the following reasons:
+ * - physical memory bank size is not necessarily the exact multiple of the
+ *   arbitrary section size
+ * - early reserved memory may not be listed in memblock.memory
+ * - memory layouts defined with memmap= kernel parameter may not align
+ *   nicely with memmap sections
+ *
+ * Explicitly initialize those struct pages so that:
+ * - PG_Reserved is set
+ * - zone and node links point to zone and node that span the page if the
+ *   hole is in the middle of a zone
+ * - zone and node links point to adjacent zone/node if the hole falls on
+ *   the zone boundary; the pages in such holes will be prepended to the
+ *   zone/node above the hole except for the trailing pages in the last
+ *   section that will be appended to the zone/node below.
+ */
+static void __init init_unavailable_range(unsigned long spfn,
+                                          unsigned long epfn,
+                                          int zone, int node)
+{
+        unsigned long pfn;
+        u64 pgcnt = 0;
+
+        for (pfn = spfn; pfn < epfn; pfn++) {
+                if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
+                        pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
+                                + pageblock_nr_pages - 1;
+                        continue;
+                }
+                __init_single_page(pfn_to_page(pfn), pfn, zone, node);
+                __SetPageReserved(pfn_to_page(pfn));
+                pgcnt++;
+        }
+
+        if (pgcnt)
+                pr_info("On node %d, zone %s: %lld pages in unavailable ranges",
+                        node, zone_names[zone], pgcnt);
+}
+#else
+static inline void init_unavailable_range(unsigned long spfn,
+                                          unsigned long epfn,
+                                          int zone, int node)
+{
+}
+#endif
+
+static void __init memmap_init_zone_range(struct zone *zone,
+                                          unsigned long start_pfn,
+                                          unsigned long end_pfn,
+                                          unsigned long *hole_pfn)
+{
+        unsigned long zone_start_pfn = zone->zone_start_pfn;
+        unsigned long zone_end_pfn = zone_start_pfn + zone->spanned_pages;
+        int nid = zone_to_nid(zone), zone_id = zone_idx(zone);
+
+        start_pfn = clamp(start_pfn, zone_start_pfn, zone_end_pfn);
+        end_pfn = clamp(end_pfn, zone_start_pfn, zone_end_pfn);
+
+        if (start_pfn >= end_pfn)
+                return;
+
+        memmap_init_zone(end_pfn - start_pfn, nid, zone_id, start_pfn,
+                          zone_end_pfn, MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
+
+        if (*hole_pfn < start_pfn)
+                init_unavailable_range(*hole_pfn, start_pfn, zone_id, nid);
+
+        *hole_pfn = end_pfn;
+}
+
+void __init __weak memmap_init(void)
+{
+        unsigned long start_pfn, end_pfn;
+        unsigned long hole_pfn = 0;
+        int i, j, zone_id, nid;
+
+        for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
+                struct pglist_data *node = NODE_DATA(nid);
+
+                for (j = 0; j < MAX_NR_ZONES; j++) {
+                        struct zone *zone = node->node_zones + j;
+
+                        if (!populated_zone(zone))
+                                continue;
+
+                        memmap_init_zone_range(zone, start_pfn, end_pfn,
+                                               &hole_pfn);
+                        zone_id = j;
+                }
+        }
+
+#ifdef CONFIG_SPARSEMEM
+        /*
+         * Initialize the memory map for hole in the range [memory_end,
+         * section_end].
+         * Append the pages in this hole to the highest zone in the last
+         * node.
+         * The call to init_unavailable_range() is outside the ifdef to
+         * silence the compiler warining about zone_id set but not used;
+         * for FLATMEM it is a nop anyway
+         */
+        end_pfn = round_up(end_pfn, PAGES_PER_SECTION);
+        if (hole_pfn < end_pfn)
+#endif
+                init_unavailable_range(hole_pfn, end_pfn, zone_id, nid);
+}
+
+/* A stub for backwards compatibility with custom implementatin on IA-64 */
+void __meminit __weak arch_memmap_init(unsigned long size, int nid,
+                                       unsigned long zone,
+                                       unsigned long range_start_pfn)
+{
+}
+
+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.
+         */
+        batch = zone_managed_pages(zone) / 1024;
+        /* But no more than a meg. */
+        if (batch * PAGE_SIZE > 1024 * 1024)
+                batch = (1024 * 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
+}
+
+/*
+ * pcp->high and pcp->batch values are related and dependent on one another:
+ * ->batch must never be higher then ->high.
+ * The following function updates them in a safe manner without read side
+ * locking.
+ *
+ * Any new users of pcp->batch and pcp->high should ensure they can cope with
+ * those fields changing asynchronously (acording to the above rule).
+ *
+ * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
+ * outside of boot time (or some other assurance that no concurrent updaters
+ * exist).
+ */
+static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
+                unsigned long batch)
+{
+       /* start with a fail safe value for batch */
+        pcp->batch = 1;
+        smp_wmb();
+
+       /* Update high, then batch, in order */
+        pcp->high = high;
+        smp_wmb();
+
+        pcp->batch = batch;
+}
+
+/* a companion to pageset_set_high() */
+static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
+{
+        pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
+}
+
+static void pageset_init(struct per_cpu_pageset *p)
+{
+        struct per_cpu_pages *pcp;
+        int migratetype;
+
+        memset(p, 0, sizeof(*p));
+
+        pcp = &p->pcp;
+        for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
+                INIT_LIST_HEAD(&pcp->lists[migratetype]);
+}
+
+static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
+{
+        pageset_init(p);
+        pageset_set_batch(p, batch);
+}
+
+/*
+ * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
+ * to the value high for the pageset p.
+ */
+static void pageset_set_high(struct per_cpu_pageset *p,
+                                unsigned long high)
+{
+        unsigned long batch = max(1UL, high / 4);
+        if ((high / 4) > (PAGE_SHIFT * 8))
+                batch = PAGE_SHIFT * 8;
+
+        pageset_update(&p->pcp, high, batch);
+}
+
+static void pageset_set_high_and_batch(struct zone *zone,
+                                       struct per_cpu_pageset *pcp)
+{
+        if (percpu_pagelist_fraction)
+                pageset_set_high(pcp,
+                        (zone_managed_pages(zone) /
+                                percpu_pagelist_fraction));
+        else
+                pageset_set_batch(pcp, zone_batchsize(zone));
+}
+
+static void __meminit zone_pageset_init(struct zone *zone, int cpu)
+{
+        struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
+
+        pageset_init(pcp);
+        pageset_set_high_and_batch(zone, pcp);
+}
+
+void __meminit setup_zone_pageset(struct zone *zone)
+{
+        int cpu;
+        zone->pageset = alloc_percpu(struct per_cpu_pageset);
+        for_each_possible_cpu(cpu)
+                zone_pageset_init(zone, cpu);
+}
+
+/*
+ * Allocate per cpu pagesets and initialize them.
+ * Before this call only boot pagesets were available.
+ */
+void __init setup_per_cpu_pageset(void)
+{
+        struct pglist_data *pgdat;
+        struct zone *zone;
+        int __maybe_unused cpu;
+
+        for_each_populated_zone(zone)
+                setup_zone_pageset(zone);
+
+#ifdef CONFIG_NUMA
+        /*
+         * Unpopulated zones continue using the boot pagesets.
+         * The numa stats for these pagesets need to be reset.
+         * Otherwise, they will end up skewing the stats of
+         * the nodes these zones are associated with.
+         */
+        for_each_possible_cpu(cpu) {
+                struct per_cpu_pageset *pcp = &per_cpu(boot_pageset, cpu);
+                memset(pcp->vm_numa_stat_diff, 0,
+                       sizeof(pcp->vm_numa_stat_diff));
+        }
+#endif
+
+        for_each_online_pgdat(pgdat)
+                pgdat->per_cpu_nodestats =
+                        alloc_percpu(struct per_cpu_nodestat);
+}
+
+static __meminit void zone_pcp_init(struct zone *zone)
+{
+        /*
+         * per cpu subsystem is not up at this point. The following code
+         * relies on the ability of the linker to provide the
+         * offset of a (static) per cpu variable into the per cpu area.
+         */
+        zone->pageset = &boot_pageset;
+
+        if (populated_zone(zone))
+                printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%u\n",
+                        zone->name, zone->present_pages,
+                                         zone_batchsize(zone));
+}
+
+void __meminit init_currently_empty_zone(struct zone *zone,
+                                        unsigned long zone_start_pfn,
+                                        unsigned long size)
+{
+        struct pglist_data *pgdat = zone->zone_pgdat;
+        int zone_idx = zone_idx(zone) + 1;
+
+        if (zone_idx > pgdat->nr_zones)
+                pgdat->nr_zones = zone_idx;
+
+        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);
+        zone->initialized = 1;
+}
+
+/**
+ * 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 memblock_set_node(). If called for a node
+ * with no available memory, a warning is printed and the start and end
+ * PFNs will be 0.
+ */
+void __init get_pfn_range_for_nid(unsigned int nid,
+                        unsigned long *start_pfn, unsigned long *end_pfn)
+{
+        unsigned long this_start_pfn, this_end_pfn;
+        int i;
+
+        *start_pfn = -1UL;
+        *end_pfn = 0;
+
+        for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
+                *start_pfn = min(*start_pfn, this_start_pfn);
+                *end_pfn = max(*end_pfn, this_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 independent 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 __init 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 (!mirrored_kernelcore &&
+                        *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 __init zone_spanned_pages_in_node(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)
+{
+        unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
+        unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
+        /* When hotadd a new node from cpu_up(), the node should be empty */
+        if (!node_start_pfn && !node_end_pfn)
+                return 0;
+
+        /* Get the start and end of the zone */
+        *zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
+        *zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
+        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.
+ */
+unsigned long __init __absent_pages_in_range(int nid,
+                                unsigned long range_start_pfn,
+                                unsigned long range_end_pfn)
+{
+        unsigned long nr_absent = range_end_pfn - range_start_pfn;
+        unsigned long start_pfn, end_pfn;
+        int i;
+
+        for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
+                start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
+                end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
+                nr_absent -= end_pfn - start_pfn;
+        }
+        return nr_absent;
+}
+
+/**
+ * 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
+ *
+ * Return: 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 __init zone_absent_pages_in_node(int nid,
+                                        unsigned long zone_type,
+                                        unsigned long node_start_pfn,
+                                        unsigned long node_end_pfn)
+{
+        unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
+        unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
+        unsigned long zone_start_pfn, zone_end_pfn;
+        unsigned long nr_absent;
+
+        /* When hotadd a new node from cpu_up(), the node should be empty */
+        if (!node_start_pfn && !node_end_pfn)
+                return 0;
+
+        zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
+        zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
+
+        adjust_zone_range_for_zone_movable(nid, zone_type,
+                        node_start_pfn, node_end_pfn,
+                        &zone_start_pfn, &zone_end_pfn);
+        nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
+
+        /*
+         * ZONE_MOVABLE handling.
+         * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
+         * and vice versa.
+         */
+        if (mirrored_kernelcore && zone_movable_pfn[nid]) {
+                unsigned long start_pfn, end_pfn;
+                struct memblock_region *r;
+
+                for_each_mem_region(r) {
+                        start_pfn = clamp(memblock_region_memory_base_pfn(r),
+                                          zone_start_pfn, zone_end_pfn);
+                        end_pfn = clamp(memblock_region_memory_end_pfn(r),
+                                        zone_start_pfn, zone_end_pfn);
+
+                        if (zone_type == ZONE_MOVABLE &&
+                            memblock_is_mirror(r))
+                                nr_absent += end_pfn - start_pfn;
+
+                        if (zone_type == ZONE_NORMAL &&
+                            !memblock_is_mirror(r))
+                                nr_absent += end_pfn - start_pfn;
+                }
+        }
+
+        return nr_absent;
+}
+
+static void __init calculate_node_totalpages(struct pglist_data *pgdat,
+                                                unsigned long node_start_pfn,
+                                                unsigned long node_end_pfn)
+{
+        unsigned long realtotalpages = 0, totalpages = 0;
+        enum zone_type i;
+
+        for (i = 0; i < MAX_NR_ZONES; i++) {
+                struct zone *zone = pgdat->node_zones + i;
+                unsigned long zone_start_pfn, zone_end_pfn;
+                unsigned long spanned, absent;
+                unsigned long size, real_size;
+
+                spanned = zone_spanned_pages_in_node(pgdat->node_id, i,
+                                                     node_start_pfn,
+                                                     node_end_pfn,
+                                                     &zone_start_pfn,
+                                                     &zone_end_pfn);
+                absent = zone_absent_pages_in_node(pgdat->node_id, i,
+                                                   node_start_pfn,
+                                                   node_end_pfn);
+
+                size = spanned;
+                real_size = size - absent;
+
+                if (size)
+                        zone->zone_start_pfn = zone_start_pfn;
+                else
+                        zone->zone_start_pfn = 0;
+                zone->spanned_pages = size;
+                zone->present_pages = real_size;
+
+                totalpages += size;
+                realtotalpages += real_size;
+        }
+
+        pgdat->node_spanned_pages = totalpages;
+        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 zone_start_pfn, unsigned long zonesize)
+{
+        unsigned long usemapsize;
+
+        zonesize += zone_start_pfn & (pageblock_nr_pages-1);
+        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 __ref setup_usemap(struct pglist_data *pgdat,
+                                struct zone *zone,
+                                unsigned long zone_start_pfn,
+                                unsigned long zonesize)
+{
+        unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
+        zone->pageblock_flags = NULL;
+        if (usemapsize) {
+                zone->pageblock_flags =
+                        memblock_alloc_node(usemapsize, SMP_CACHE_BYTES,
+                                            pgdat->node_id);
+                if (!zone->pageblock_flags)
+                        panic("Failed to allocate %ld bytes for zone %s pageblock flags on node %d\n",
+                              usemapsize, zone->name, pgdat->node_id);
+        }
+}
+#else
+static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
+                                unsigned long zone_start_pfn, unsigned long zonesize) {}
+#endif /* CONFIG_SPARSEMEM */
+
+#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
+
+/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
+void __init set_pageblock_order(void)
+{
+        unsigned int order;
+
+        /* Check that pageblock_nr_pages has not already been setup */
+        if (pageblock_order)
+                return;
+
+        if (HPAGE_SHIFT > PAGE_SHIFT)
+                order = HUGETLB_PAGE_ORDER;
+        else
+                order = MAX_ORDER - 1;
+
+        /*
+         * Assume the largest contiguous order of interest is a huge page.
+         * This value may be variable depending on boot parameters on IA64 and
+         * powerpc.
+         */
+        pageblock_order = order;
+}
+#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
+
+/*
+ * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
+ * is 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
+ */
+void __init set_pageblock_order(void)
+{
+}
+
+#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
+
+static unsigned long __init calc_memmap_size(unsigned long spanned_pages,
+                                                unsigned long present_pages)
+{
+        unsigned long pages = spanned_pages;
+
+        /*
+         * Provide a more accurate estimation if there are holes within
+         * the zone and SPARSEMEM is in use. If there are holes within the
+         * zone, each populated memory region may cost us one or two extra
+         * memmap pages due to alignment because memmap pages for each
+         * populated regions may not be naturally aligned on page boundary.
+         * So the (present_pages >> 4) heuristic is a tradeoff for that.
+         */
+        if (spanned_pages > present_pages + (present_pages >> 4) &&
+            IS_ENABLED(CONFIG_SPARSEMEM))
+                pages = present_pages;
+
+        return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static void pgdat_init_split_queue(struct pglist_data *pgdat)
+{
+        struct deferred_split *ds_queue = &pgdat->deferred_split_queue;
+
+        spin_lock_init(&ds_queue->split_queue_lock);
+        INIT_LIST_HEAD(&ds_queue->split_queue);
+        ds_queue->split_queue_len = 0;
+}
+#else
+static void pgdat_init_split_queue(struct pglist_data *pgdat) {}
+#endif
+
+#ifdef CONFIG_COMPACTION
+static void pgdat_init_kcompactd(struct pglist_data *pgdat)
+{
+        init_waitqueue_head(&pgdat->kcompactd_wait);
+}
+#else
+static void pgdat_init_kcompactd(struct pglist_data *pgdat) {}
+#endif
+
+static void __meminit pgdat_init_internals(struct pglist_data *pgdat)
+{
+        pgdat_resize_init(pgdat);
+
+        pgdat_init_split_queue(pgdat);
+        pgdat_init_kcompactd(pgdat);
+
+        init_waitqueue_head(&pgdat->kswapd_wait);
+        init_waitqueue_head(&pgdat->pfmemalloc_wait);
+#ifdef CONFIG_HYPERHOLD_ZSWAPD
+        init_waitqueue_head(&pgdat->zswapd_wait);
+#endif
+
+        pgdat_page_ext_init(pgdat);
+        spin_lock_init(&pgdat->lru_lock);
+        lruvec_init(&pgdat->__lruvec);
+#if defined(CONFIG_HYPERHOLD_FILE_LRU) && defined(CONFIG_MEMCG)
+        pgdat->__lruvec.pgdat = pgdat;
+#endif
+}
+
+static void __meminit zone_init_internals(struct zone *zone, enum zone_type idx, int nid,
+                                                        unsigned long remaining_pages)
+{
+        atomic_long_set(&zone->managed_pages, remaining_pages);
+        zone_set_nid(zone, nid);
+        zone->name = zone_names[idx];
+        zone->zone_pgdat = NODE_DATA(nid);
+        spin_lock_init(&zone->lock);
+        zone_seqlock_init(zone);
+        zone_pcp_init(zone);
+}
+
+/*
+ * Set up the zone data structures
+ * - init pgdat internals
+ * - init all zones belonging to this node
+ *
+ * NOTE: this function is only called during memory hotplug
+ */
+#ifdef CONFIG_MEMORY_HOTPLUG
+void __ref free_area_init_core_hotplug(int nid)
+{
+        enum zone_type z;
+        pg_data_t *pgdat = NODE_DATA(nid);
+
+        pgdat_init_internals(pgdat);
+        for (z = 0; z < MAX_NR_ZONES; z++)
+                zone_init_internals(&pgdat->node_zones[z], z, nid, 0);
+}
+#endif
+
+/*
+ * Set up the zone data structures:
+ *   - mark all pages reserved
+ *   - mark all memory queues empty
+ *   - clear the memory bitmaps
+ *
+ * NOTE: pgdat should get zeroed by caller.
+ * NOTE: this function is only called during early init.
+ */
+static void __init free_area_init_core(struct pglist_data *pgdat)
+{
+        enum zone_type j;
+        int nid = pgdat->node_id;
+
+        pgdat_init_internals(pgdat);
+        pgdat->per_cpu_nodestats = &boot_nodestats;
+
+        for (j = 0; j < MAX_NR_ZONES; j++) {
+                struct zone *zone = pgdat->node_zones + j;
+                unsigned long size, freesize, memmap_pages;
+                unsigned long zone_start_pfn = zone->zone_start_pfn;
+
+                size = zone->spanned_pages;
+                freesize = zone->present_pages;
+
+                /*
+                 * Adjust freesize 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 = calc_memmap_size(size, freesize);
+                if (!is_highmem_idx(j)) {
+                        if (freesize >= memmap_pages) {
+                                freesize -= memmap_pages;
+                                if (memmap_pages)
+                                        printk(KERN_DEBUG
+                                               "  %s zone: %lu pages used for memmap\n",
+                                               zone_names[j], memmap_pages);
+                        } else
+                                pr_warn("  %s zone: %lu pages exceeds freesize %lu\n",
+                                        zone_names[j], memmap_pages, freesize);
+                }
+
+                /* Account for reserved pages */
+                if (j == 0 && freesize > dma_reserve) {
+                        freesize -= dma_reserve;
+                        printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
+                                        zone_names[0], dma_reserve);
+                }
+
+                if (!is_highmem_idx(j))
+                        nr_kernel_pages += freesize;
+                /* Charge for highmem memmap if there are enough kernel pages */
+                else if (nr_kernel_pages > memmap_pages * 2)
+                        nr_kernel_pages -= memmap_pages;
+                nr_all_pages += freesize;
+
+                /*
+                 * Set an approximate value for lowmem here, it will be adjusted
+                 * when the bootmem allocator frees pages into the buddy system.
+                 * And all highmem pages will be managed by the buddy system.
+                 */
+                zone_init_internals(zone, j, nid, freesize);
+
+                if (!size)
+                        continue;
+
+                set_pageblock_order();
+                setup_usemap(pgdat, zone, zone_start_pfn, size);
+                init_currently_empty_zone(zone, zone_start_pfn, size);
+                arch_memmap_init(size, nid, j, zone_start_pfn);
+        }
+}
+
+#ifdef CONFIG_FLAT_NODE_MEM_MAP
+static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
+{
+        unsigned long __maybe_unused start = 0;
+        unsigned long __maybe_unused offset = 0;
+
+        /* Skip empty nodes */
+        if (!pgdat->node_spanned_pages)
+                return;
+
+        start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
+        offset = pgdat->node_start_pfn - start;
+        /* ia64 gets its own node_mem_map, before this, without bootmem */
+        if (!pgdat->node_mem_map) {
+                unsigned long size, 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.
+                 */
+                end = pgdat_end_pfn(pgdat);
+                end = ALIGN(end, MAX_ORDER_NR_PAGES);
+                size =  (end - start) * sizeof(struct page);
+                map = memblock_alloc_node(size, SMP_CACHE_BYTES,
+                                          pgdat->node_id);
+                if (!map)
+                        panic("Failed to allocate %ld bytes for node %d memory map\n",
+                              size, pgdat->node_id);
+                pgdat->node_mem_map = map + offset;
+        }
+        pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
+                                __func__, pgdat->node_id, (unsigned long)pgdat,
+                                (unsigned long)pgdat->node_mem_map);
+#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;
+                if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
+                        mem_map -= offset;
+        }
+#endif
+}
+#else
+static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { }
+#endif /* CONFIG_FLAT_NODE_MEM_MAP */
+
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
+{
+        pgdat->first_deferred_pfn = ULONG_MAX;
+}
+#else
+static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
+#endif
+
+static void __init free_area_init_node(int nid)
+{
+        pg_data_t *pgdat = NODE_DATA(nid);
+        unsigned long start_pfn = 0;
+        unsigned long end_pfn = 0;
+
+        /* pg_data_t should be reset to zero when it's allocated */
+        WARN_ON(pgdat->nr_zones || pgdat->kswapd_highest_zoneidx);
+
+        get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
+
+        pgdat->node_id = nid;
+        pgdat->node_start_pfn = start_pfn;
+        pgdat->per_cpu_nodestats = NULL;
+
+        pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
+                (u64)start_pfn << PAGE_SHIFT,
+                end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
+        calculate_node_totalpages(pgdat, start_pfn, end_pfn);
+
+        alloc_node_mem_map(pgdat);
+        pgdat_set_deferred_range(pgdat);
+
+        free_area_init_core(pgdat);
+}
+
+void __init free_area_init_memoryless_node(int nid)
+{
+        free_area_init_node(nid);
+}
+
+#if MAX_NUMNODES > 1
+/*
+ * Figure out the number of possible node ids.
+ */
+void __init setup_nr_node_ids(void)
+{
+        unsigned int highest;
+
+        highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES);
+        nr_node_ids = highest + 1;
+}
+#endif
+
+/**
+ * node_map_pfn_alignment - determine the maximum internode alignment
+ *
+ * This function should be called after node map is populated and sorted.
+ * It calculates the maximum power of two alignment which can distinguish
+ * all the nodes.
+ *
+ * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
+ * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)).  If the
+ * nodes are shifted by 256MiB, 256MiB.  Note that if only the last node is
+ * shifted, 1GiB is enough and this function will indicate so.
+ *
+ * This is used to test whether pfn -> nid mapping of the chosen memory
+ * model has fine enough granularity to avoid incorrect mapping for the
+ * populated node map.
+ *
+ * Return: the determined alignment in pfn's.  0 if there is no alignment
+ * requirement (single node).
+ */
+unsigned long __init node_map_pfn_alignment(void)
+{
+        unsigned long accl_mask = 0, last_end = 0;
+        unsigned long start, end, mask;
+        int last_nid = NUMA_NO_NODE;
+        int i, nid;
+
+        for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
+                if (!start || last_nid < 0 || last_nid == nid) {
+                        last_nid = nid;
+                        last_end = end;
+                        continue;
+                }
+
+                /*
+                 * Start with a mask granular enough to pin-point to the
+                 * start pfn and tick off bits one-by-one until it becomes
+                 * too coarse to separate the current node from the last.
+                 */
+                mask = ~((1 << __ffs(start)) - 1);
+                while (mask && last_end <= (start & (mask << 1)))
+                        mask <<= 1;
+
+                /* accumulate all internode masks */
+                accl_mask |= mask;
+        }
+
+        /* convert mask to number of pages */
+        return ~accl_mask + 1;
+}
+
+/**
+ * find_min_pfn_with_active_regions - Find the minimum PFN registered
+ *
+ * Return: the minimum PFN based on information provided via
+ * memblock_set_node().
+ */
+unsigned long __init find_min_pfn_with_active_regions(void)
+{
+        return PHYS_PFN(memblock_start_of_DRAM());
+}
+
+/*
+ * early_calculate_totalpages()
+ * Sum pages in active regions for movable zone.
+ * Populate N_MEMORY for calculating usable_nodes.
+ */
+static unsigned long __init early_calculate_totalpages(void)
+{
+        unsigned long totalpages = 0;
+        unsigned long start_pfn, end_pfn;
+        int i, nid;
+
+        for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
+                unsigned long pages = end_pfn - start_pfn;
+
+                totalpages += pages;
+                if (pages)
+                        node_set_state(nid, N_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(void)
+{
+        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_MEMORY];
+        unsigned long totalpages = early_calculate_totalpages();
+        int usable_nodes = nodes_weight(node_states[N_MEMORY]);
+        struct memblock_region *r;
+
+        /* Need to find movable_zone earlier when movable_node is specified. */
+        find_usable_zone_for_movable();
+
+        /*
+         * If movable_node is specified, ignore kernelcore and movablecore
+         * options.
+         */
+        if (movable_node_is_enabled()) {
+                for_each_mem_region(r) {
+                        if (!memblock_is_hotpluggable(r))
+                                continue;
+
+                        nid = memblock_get_region_node(r);
+
+                        usable_startpfn = PFN_DOWN(r->base);
+                        zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
+                                min(usable_startpfn, zone_movable_pfn[nid]) :
+                                usable_startpfn;
+                }
+
+                goto out2;
+        }
+
+        /*
+         * If kernelcore=mirror is specified, ignore movablecore option
+         */
+        if (mirrored_kernelcore) {
+                bool mem_below_4gb_not_mirrored = false;
+
+                for_each_mem_region(r) {
+                        if (memblock_is_mirror(r))
+                                continue;
+
+                        nid = memblock_get_region_node(r);
+
+                        usable_startpfn = memblock_region_memory_base_pfn(r);
+
+                        if (usable_startpfn < 0x100000) {
+                                mem_below_4gb_not_mirrored = true;
+                                continue;
+                        }
+
+                        zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
+                                min(usable_startpfn, zone_movable_pfn[nid]) :
+                                usable_startpfn;
+                }
+
+                if (mem_below_4gb_not_mirrored)
+                        pr_warn("This configuration results in unmirrored kernel memory.\n");
+
+                goto out2;
+        }
+
+        /*
+         * If kernelcore=nn% or movablecore=nn% was specified, calculate the
+         * amount of necessary memory.
+         */
+        if (required_kernelcore_percent)
+                required_kernelcore = (totalpages * 100 * required_kernelcore_percent) /
+                                       10000UL;
+        if (required_movablecore_percent)
+                required_movablecore = (totalpages * 100 * required_movablecore_percent) /
+                                        10000UL;
+
+        /*
+         * 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);
+                required_movablecore = min(totalpages, required_movablecore);
+                corepages = totalpages - required_movablecore;
+
+                required_kernelcore = max(required_kernelcore, corepages);
+        }
+
+        /*
+         * If kernelcore was not specified or kernelcore size is larger
+         * than totalpages, there is no ZONE_MOVABLE.
+         */
+        if (!required_kernelcore || required_kernelcore >= totalpages)
+                goto out;
+
+        /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
+        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_MEMORY) {
+                unsigned long start_pfn, end_pfn;
+
+                /*
+                 * 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_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
+                        unsigned long size_pages;
+
+                        start_pfn = max(start_pfn, zone_movable_pfn[nid]);
+                        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
+                         * satisfied
+                         */
+                        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
+         * satisfied
+         */
+        usable_nodes--;
+        if (usable_nodes && required_kernelcore > usable_nodes)
+                goto restart;
+
+out2:
+        /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
+        for (nid = 0; nid < MAX_NUMNODES; nid++) {
+                unsigned long start_pfn, end_pfn;
+
+                zone_movable_pfn[nid] =
+                        roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
+
+                get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
+                if (zone_movable_pfn[nid] >= end_pfn)
+                        zone_movable_pfn[nid] = 0;
+        }
+
+out:
+        /* restore the node_state */
+        node_states[N_MEMORY] = saved_node_state;
+}
+
+/* Any regular or high memory on that node ? */
+static void check_for_memory(pg_data_t *pgdat, int nid)
+{
+        enum zone_type zone_type;
+
+        for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
+                struct zone *zone = &pgdat->node_zones[zone_type];
+                if (populated_zone(zone)) {
+                        if (IS_ENABLED(CONFIG_HIGHMEM))
+                                node_set_state(nid, N_HIGH_MEMORY);
+                        if (zone_type <= ZONE_NORMAL)
+                                node_set_state(nid, N_NORMAL_MEMORY);
+                        break;
+                }
+        }
+}
+
+/*
+ * Some architecturs, e.g. ARC may have ZONE_HIGHMEM below ZONE_NORMAL. For
+ * such cases we allow max_zone_pfn sorted in the descending order
+ */
+bool __weak arch_has_descending_max_zone_pfns(void)
+{
+        return false;
+}
+
+/**
+ * free_area_init - 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 memblock_set_node(), 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(unsigned long *max_zone_pfn)
+{
+        unsigned long start_pfn, end_pfn;
+        int i, nid, zone;
+        bool descending;
+
+        /* 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));
+
+        start_pfn = find_min_pfn_with_active_regions();
+        descending = arch_has_descending_max_zone_pfns();
+
+        for (i = 0; i < MAX_NR_ZONES; i++) {
+                if (descending)
+                        zone = MAX_NR_ZONES - i - 1;
+                else
+                        zone = i;
+
+                if (zone == ZONE_MOVABLE)
+                        continue;
+
+                end_pfn = max(max_zone_pfn[zone], start_pfn);
+                arch_zone_lowest_possible_pfn[zone] = start_pfn;
+                arch_zone_highest_possible_pfn[zone] = end_pfn;
+
+                start_pfn = end_pfn;
+        }
+
+        /* 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();
+
+        /* Print out the zone ranges */
+        pr_info("Zone ranges:\n");
+        for (i = 0; i < MAX_NR_ZONES; i++) {
+                if (i == ZONE_MOVABLE)
+                        continue;
+                pr_info("  %-8s ", zone_names[i]);
+                if (arch_zone_lowest_possible_pfn[i] ==
+                                arch_zone_highest_possible_pfn[i])
+                        pr_cont("empty\n");
+                else
+                        pr_cont("[mem %#018Lx-%#018Lx]\n",
+                                (u64)arch_zone_lowest_possible_pfn[i]
+                                        << PAGE_SHIFT,
+                                ((u64)arch_zone_highest_possible_pfn[i]
+                                        << PAGE_SHIFT) - 1);
+        }
+
+        /* Print out the PFNs ZONE_MOVABLE begins at in each node */
+        pr_info("Movable zone start for each node\n");
+        for (i = 0; i < MAX_NUMNODES; i++) {
+                if (zone_movable_pfn[i])
+                        pr_info("  Node %d: %#018Lx\n", i,
+                               (u64)zone_movable_pfn[i] << PAGE_SHIFT);
+        }
+
+        /*
+         * Print out the early node map, and initialize the
+         * subsection-map relative to active online memory ranges to
+         * enable future "sub-section" extensions of the memory map.
+         */
+        pr_info("Early memory node ranges\n");
+        for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
+                pr_info("  node %3d: [mem %#018Lx-%#018Lx]\n", nid,
+                        (u64)start_pfn << PAGE_SHIFT,
+                        ((u64)end_pfn << PAGE_SHIFT) - 1);
+                subsection_map_init(start_pfn, end_pfn - start_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);
+
+                /* Any memory on that node */
+                if (pgdat->node_present_pages)
+                        node_set_state(nid, N_MEMORY);
+                check_for_memory(pgdat, nid);
+        }
+
+        memmap_init();
+}
+
+static int __init cmdline_parse_core(char *p, unsigned long *core,
+                                     unsigned long *percent)
+{
+        unsigned long long coremem;
+        char *endptr;
+
+        if (!p)
+                return -EINVAL;
+
+        /* Value may be a percentage of total memory, otherwise bytes */
+        coremem = simple_strtoull(p, &endptr, 0);
+        if (*endptr == '%') {
+                /* Paranoid check for percent values greater than 100 */
+                WARN_ON(coremem > 100);
+
+                *percent = coremem;
+        } else {
+                coremem = memparse(p, &p);
+                /* Paranoid check that UL is enough for the coremem value */
+                WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
+
+                *core = coremem >> PAGE_SHIFT;
+                *percent = 0UL;
+        }
+        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)
+{
+        /* parse kernelcore=mirror */
+        if (parse_option_str(p, "mirror")) {
+                mirrored_kernelcore = true;
+                return 0;
+        }
+
+        return cmdline_parse_core(p, &required_kernelcore,
+                                  &required_kernelcore_percent);
+}
+
+/*
+ * 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,
+                                  &required_movablecore_percent);
+}
+
+early_param("kernelcore", cmdline_parse_kernelcore);
+early_param("movablecore", cmdline_parse_movablecore);
+
+void adjust_managed_page_count(struct page *page, long count)
+{
+        atomic_long_add(count, &page_zone(page)->managed_pages);
+        totalram_pages_add(count);
+#ifdef CONFIG_HIGHMEM
+        if (PageHighMem(page))
+                totalhigh_pages_add(count);
+#endif
+}
+EXPORT_SYMBOL(adjust_managed_page_count);
+
+unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
+{
+        void *pos;
+        unsigned long pages = 0;
+
+        start = (void *)PAGE_ALIGN((unsigned long)start);
+        end = (void *)((unsigned long)end & PAGE_MASK);
+        for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
+                struct page *page = virt_to_page(pos);
+                void *direct_map_addr;
+
+                /*
+                 * 'direct_map_addr' might be different from 'pos'
+                 * because some architectures' virt_to_page()
+                 * work with aliases.  Getting the direct map
+                 * address ensures that we get a _writeable_
+                 * alias for the memset().
+                 */
+                direct_map_addr = page_address(page);
+                if ((unsigned int)poison <= 0xFF)
+                        memset(direct_map_addr, poison, PAGE_SIZE);
+
+                free_reserved_page(page);
+        }
+
+        if (pages && s)
+                pr_info("Freeing %s memory: %ldK\n",
+                        s, pages << (PAGE_SHIFT - 10));
+
+        return pages;
+}
+
+#ifdef  CONFIG_HIGHMEM
+void free_highmem_page(struct page *page)
+{
+        __free_reserved_page(page);
+        totalram_pages_inc();
+        atomic_long_inc(&page_zone(page)->managed_pages);
+        totalhigh_pages_inc();
+}
+#endif
+
+
+void __init mem_init_print_info(const char *str)
+{
+        unsigned long physpages, codesize, datasize, rosize, bss_size;
+        unsigned long init_code_size, init_data_size;
+
+        physpages = get_num_physpages();
+        codesize = _etext - _stext;
+        datasize = _edata - _sdata;
+        rosize = __end_rodata - __start_rodata;
+        bss_size = __bss_stop - __bss_start;
+        init_data_size = __init_end - __init_begin;
+        init_code_size = _einittext - _sinittext;
+
+        /*
+         * Detect special cases and adjust section sizes accordingly:
+         * 1) .init.* may be embedded into .data sections
+         * 2) .init.text.* may be out of [__init_begin, __init_end],
+         *    please refer to arch/tile/kernel/vmlinux.lds.S.
+         * 3) .rodata.* may be embedded into .text or .data sections.
+         */
+#define adj_init_size(start, end, size, pos, adj) \
+        do { \
+                if (&start[0] <= &pos[0] && &pos[0] < &end[0] && size > adj) \
+                        size -= adj; \
+        } while (0)
+
+        adj_init_size(__init_begin, __init_end, init_data_size,
+                     _sinittext, init_code_size);
+        adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
+        adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
+        adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
+        adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
+
+#undef  adj_init_size
+
+        pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
+#ifdef  CONFIG_HIGHMEM
+                ", %luK highmem"
+#endif
+                "%s%s)\n",
+                nr_free_pages() << (PAGE_SHIFT - 10),
+                physpages << (PAGE_SHIFT - 10),
+                codesize >> 10, datasize >> 10, rosize >> 10,
+                (init_data_size + init_code_size) >> 10, bss_size >> 10,
+                (physpages - totalram_pages() - totalcma_pages) << (PAGE_SHIFT - 10),
+                totalcma_pages << (PAGE_SHIFT - 10),
+#ifdef  CONFIG_HIGHMEM
+                totalhigh_pages() << (PAGE_SHIFT - 10),
+#endif
+                str ? ", " : "", str ? str : "");
+}
+
+/**
+ * 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 managed_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;
+}
+
+static int page_alloc_cpu_dead(unsigned int cpu)
+{
+
+        lru_add_drain_cpu(cpu);
+        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.
+         */
+        cpu_vm_stats_fold(cpu);
+        return 0;
+}
+
+#ifdef CONFIG_NUMA
+int hashdist = HASHDIST_DEFAULT;
+
+static int __init set_hashdist(char *str)
+{
+        if (!str)
+                return 0;
+        hashdist = simple_strtoul(str, &str, 0);
+        return 1;
+}
+__setup("hashdist=", set_hashdist);
+#endif
+
+void __init page_alloc_init(void)
+{
+        int ret;
+
+#ifdef CONFIG_NUMA
+        if (num_node_state(N_MEMORY) == 1)
+                hashdist = 0;
+#endif
+
+        ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC_DEAD,
+                                        "mm/page_alloc:dead", NULL,
+                                        page_alloc_cpu_dead);
+        WARN_ON(ret < 0);
+}
+
+/*
+ * calculate_totalreserve_pages - called when sysctl_lowmem_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) {
+
+                pgdat->totalreserve_pages = 0;
+
+                for (i = 0; i < MAX_NR_ZONES; i++) {
+                        struct zone *zone = pgdat->node_zones + i;
+                        long max = 0;
+                        unsigned long managed_pages = zone_managed_pages(zone);
+
+                        /* 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 > managed_pages)
+                                max = managed_pages;
+
+                        pgdat->totalreserve_pages += max;
+
+                        reserve_pages += max;
+                }
+        }
+        totalreserve_pages = reserve_pages;
+}
+
+/*
+ * setup_per_zone_lowmem_reserve - called whenever
+ *      sysctl_lowmem_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 i, j;
+
+        for_each_online_pgdat(pgdat) {
+                for (i = 0; i < MAX_NR_ZONES - 1; i++) {
+                        struct zone *zone = &pgdat->node_zones[i];
+                        int ratio = sysctl_lowmem_reserve_ratio[i];
+                        bool clear = !ratio || !zone_managed_pages(zone);
+                        unsigned long managed_pages = 0;
+
+                        for (j = i + 1; j < MAX_NR_ZONES; j++) {
+                                struct zone *upper_zone = &pgdat->node_zones[j];
+
+                                managed_pages += zone_managed_pages(upper_zone);
+
+                                if (clear)
+                                        zone->lowmem_reserve[j] = 0;
+                                else
+                                        zone->lowmem_reserve[j] = managed_pages / ratio;
+                        }
+                }
+        }
+
+        /* update totalreserve_pages */
+        calculate_totalreserve_pages();
+}
+
+static 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_managed_pages(zone);
+        }
+
+        for_each_zone(zone) {
+                u64 tmp;
+
+                spin_lock_irqsave(&zone->lock, flags);
+                tmp = (u64)pages_min * zone_managed_pages(zone);
+                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 control async page reclaim, and so should
+                         * not be capped for highmem.
+                         */
+                        unsigned long min_pages;
+
+                        min_pages = zone_managed_pages(zone) / 1024;
+                        min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
+                        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;
+                }
+
+                /*
+                 * Set the kswapd watermarks distance according to the
+                 * scale factor in proportion to available memory, but
+                 * ensure a minimum size on small systems.
+                 */
+                tmp = max_t(u64, tmp >> 2,
+                            mult_frac(zone_managed_pages(zone),
+                                      watermark_scale_factor, 10000));
+
+                zone->watermark_boost = 0;
+                zone->_watermark[WMARK_LOW]  = min_wmark_pages(zone) + tmp;
+                zone->_watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;
+
+                spin_unlock_irqrestore(&zone->lock, flags);
+        }
+
+        /* 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)
+{
+        static DEFINE_SPINLOCK(lock);
+
+        spin_lock(&lock);
+        __setup_per_zone_wmarks();
+        spin_unlock(&lock);
+}
+
+/*
+ * Initialise min_free_kbytes.
+ *
+ * For small machines we want it small (128k min).  For large machines
+ * we want it large (256MB 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
+ */
+int __meminit init_per_zone_wmark_min(void)
+{
+        unsigned long lowmem_kbytes;
+        int new_min_free_kbytes;
+
+        lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
+        new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
+
+        if (new_min_free_kbytes > user_min_free_kbytes) {
+                min_free_kbytes = new_min_free_kbytes;
+                if (min_free_kbytes < 128)
+                        min_free_kbytes = 128;
+                if (min_free_kbytes > 262144)
+                        min_free_kbytes = 262144;
+        } else {
+                pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
+                                new_min_free_kbytes, user_min_free_kbytes);
+        }
+        setup_per_zone_wmarks();
+        refresh_zone_stat_thresholds();
+        setup_per_zone_lowmem_reserve();
+
+#ifdef CONFIG_NUMA
+        setup_min_unmapped_ratio();
+        setup_min_slab_ratio();
+#endif
+
+        khugepaged_min_free_kbytes_update();
+
+        return 0;
+}
+postcore_initcall(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(struct ctl_table *table, int write,
+                void *buffer, size_t *length, loff_t *ppos)
+{
+        int rc;
+
+        rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
+        if (rc)
+                return rc;
+
+        if (write) {
+                user_min_free_kbytes = min_free_kbytes;
+                setup_per_zone_wmarks();
+        }
+        return 0;
+}
+
+int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
+                void *buffer, size_t *length, loff_t *ppos)
+{
+        int rc;
+
+        rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
+        if (rc)
+                return rc;
+
+        if (write)
+                setup_per_zone_wmarks();
+
+        return 0;
+}
+
+#ifdef CONFIG_NUMA
+static void setup_min_unmapped_ratio(void)
+{
+        pg_data_t *pgdat;
+        struct zone *zone;
+
+        for_each_online_pgdat(pgdat)
+                pgdat->min_unmapped_pages = 0;
+
+        for_each_zone(zone)
+                zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) *
+                                                         sysctl_min_unmapped_ratio) / 100;
+}
+
+
+int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
+                void *buffer, size_t *length, loff_t *ppos)
+{
+        int rc;
+
+        rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
+        if (rc)
+                return rc;
+
+        setup_min_unmapped_ratio();
+
+        return 0;
+}
+
+static void setup_min_slab_ratio(void)
+{
+        pg_data_t *pgdat;
+        struct zone *zone;
+
+        for_each_online_pgdat(pgdat)
+                pgdat->min_slab_pages = 0;
+
+        for_each_zone(zone)
+                zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) *
+                                                     sysctl_min_slab_ratio) / 100;
+}
+
+int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
+                void *buffer, size_t *length, loff_t *ppos)
+{
+        int rc;
+
+        rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
+        if (rc)
+                return rc;
+
+        setup_min_slab_ratio();
+
+        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(struct ctl_table *table, int write,
+                void *buffer, size_t *length, loff_t *ppos)
+{
+        int i;
+
+        proc_dointvec_minmax(table, write, buffer, length, ppos);
+
+        for (i = 0; i < MAX_NR_ZONES; i++) {
+                if (sysctl_lowmem_reserve_ratio[i] < 1)
+                        sysctl_lowmem_reserve_ratio[i] = 0;
+        }
+
+        setup_per_zone_lowmem_reserve();
+        return 0;
+}
+
+static void __zone_pcp_update(struct zone *zone)
+{
+        unsigned int cpu;
+
+        for_each_possible_cpu(cpu)
+                pageset_set_high_and_batch(zone,
+                                per_cpu_ptr(zone->pageset, cpu));
+}
+
+/*
+ * 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(struct ctl_table *table, int write,
+                void *buffer, size_t *length, loff_t *ppos)
+{
+        struct zone *zone;
+        int old_percpu_pagelist_fraction;
+        int ret;
+
+        mutex_lock(&pcp_batch_high_lock);
+        old_percpu_pagelist_fraction = percpu_pagelist_fraction;
+
+        ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
+        if (!write || ret < 0)
+                goto out;
+
+        /* Sanity checking to avoid pcp imbalance */
+        if (percpu_pagelist_fraction &&
+            percpu_pagelist_fraction < MIN_PERCPU_PAGELIST_FRACTION) {
+                percpu_pagelist_fraction = old_percpu_pagelist_fraction;
+                ret = -EINVAL;
+                goto out;
+        }
+
+        /* No change? */
+        if (percpu_pagelist_fraction == old_percpu_pagelist_fraction)
+                goto out;
+
+        for_each_populated_zone(zone)
+                __zone_pcp_update(zone);
+out:
+        mutex_unlock(&pcp_batch_high_lock);
+        return ret;
+}
+
+#ifndef __HAVE_ARCH_RESERVED_KERNEL_PAGES
+/*
+ * Returns the number of pages that arch has reserved but
+ * is not known to alloc_large_system_hash().
+ */
+static unsigned long __init arch_reserved_kernel_pages(void)
+{
+        return 0;
+}
+#endif
+
+/*
+ * Adaptive scale is meant to reduce sizes of hash tables on large memory
+ * machines. As memory size is increased the scale is also increased but at
+ * slower pace.  Starting from ADAPT_SCALE_BASE (64G), every time memory
+ * quadruples the scale is increased by one, which means the size of hash table
+ * only doubles, instead of quadrupling as well.
+ * Because 32-bit systems cannot have large physical memory, where this scaling
+ * makes sense, it is disabled on such platforms.
+ */
+#if __BITS_PER_LONG > 32
+#define ADAPT_SCALE_BASE        (64ul << 30)
+#define ADAPT_SCALE_SHIFT       2
+#define ADAPT_SCALE_NPAGES      (ADAPT_SCALE_BASE >> PAGE_SHIFT)
+#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 low_limit,
+                                     unsigned long high_limit)
+{
+        unsigned long long max = high_limit;
+        unsigned long log2qty, size;
+        void *table = NULL;
+        gfp_t gfp_flags;
+        bool virt;
+
+        /* allow the kernel cmdline to have a say */
+        if (!numentries) {
+                /* round applicable memory size up to nearest megabyte */
+                numentries = nr_kernel_pages;
+                numentries -= arch_reserved_kernel_pages();
+
+                /* It isn't necessary when PAGE_SIZE >= 1MB */
+                if (PAGE_SHIFT < 20)
+                        numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
+
+#if __BITS_PER_LONG > 32
+                if (!high_limit) {
+                        unsigned long adapt;
+
+                        for (adapt = ADAPT_SCALE_NPAGES; adapt < numentries;
+                             adapt <<= ADAPT_SCALE_SHIFT)
+                                scale++;
+                }
+#endif
+
+                /* 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(flags & HASH_SMALL)) {
+                        /* Makes no sense without HASH_EARLY */
+                        WARN_ON(!(flags & HASH_EARLY));
+                        if (!(numentries >> *_hash_shift)) {
+                                numentries = 1UL << *_hash_shift;
+                                BUG_ON(!numentries);
+                        }
+                } else 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);
+        }
+        max = min(max, 0x80000000ULL);
+
+        if (numentries < low_limit)
+                numentries = low_limit;
+        if (numentries > max)
+                numentries = max;
+
+        log2qty = ilog2(numentries);
+
+        gfp_flags = (flags & HASH_ZERO) ? GFP_ATOMIC | __GFP_ZERO : GFP_ATOMIC;
+        do {
+                virt = false;
+                size = bucketsize << log2qty;
+                if (flags & HASH_EARLY) {
+                        if (flags & HASH_ZERO)
+                                table = memblock_alloc(size, SMP_CACHE_BYTES);
+                        else
+                                table = memblock_alloc_raw(size,
+                                                           SMP_CACHE_BYTES);
+                } else if (get_order(size) >= MAX_ORDER || hashdist) {
+                        table = __vmalloc(size, gfp_flags);
+                        virt = true;
+                } 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
+                         */
+                        table = alloc_pages_exact(size, gfp_flags);
+                        kmemleak_alloc(table, size, 1, gfp_flags);
+                }
+        } while (!table && size > PAGE_SIZE && --log2qty);
+
+        if (!table)
+                panic("Failed to allocate %s hash table\n", tablename);
+
+        pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
+                tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
+                virt ? "vmalloc" : "linear");
+
+        if (_hash_shift)
+                *_hash_shift = log2qty;
+        if (_hash_mask)
+                *_hash_mask = (1 << log2qty) - 1;
+
+        return table;
+}
+
+/*
+ * This function checks whether pageblock includes unmovable pages or not.
+ *
+ * PageLRU check without isolation or lru_lock could race so that
+ * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
+ * check without lock_page also may miss some movable non-lru pages at
+ * race condition. So you can't expect this function should be exact.
+ *
+ * Returns a page without holding a reference. If the caller wants to
+ * dereference that page (e.g., dumping), it has to make sure that it
+ * cannot get removed (e.g., via memory unplug) concurrently.
+ *
+ */
+struct page *has_unmovable_pages(struct zone *zone, struct page *page,
+                                 int migratetype, int flags)
+{
+        unsigned long iter = 0;
+        unsigned long pfn = page_to_pfn(page);
+        unsigned long offset = pfn % pageblock_nr_pages;
+
+        if (is_migrate_cma_page(page)) {
+                /*
+                 * CMA allocations (alloc_contig_range) really need to mark
+                 * isolate CMA pageblocks even when they are not movable in fact
+                 * so consider them movable here.
+                 */
+                if (is_migrate_cma(migratetype))
+                        return NULL;
+
+                return page;
+        }
+
+        for (; iter < pageblock_nr_pages - offset; iter++) {
+                if (!pfn_valid_within(pfn + iter))
+                        continue;
+
+                page = pfn_to_page(pfn + iter);
+
+                /*
+                 * Both, bootmem allocations and memory holes are marked
+                 * PG_reserved and are unmovable. We can even have unmovable
+                 * allocations inside ZONE_MOVABLE, for example when
+                 * specifying "movablecore".
+                 */
+                if (PageReserved(page))
+                        return page;
+
+                /*
+                 * If the zone is movable and we have ruled out all reserved
+                 * pages then it should be reasonably safe to assume the rest
+                 * is movable.
+                 */
+                if (zone_idx(zone) == ZONE_MOVABLE)
+                        continue;
+
+                /*
+                 * Hugepages are not in LRU lists, but they're movable.
+                 * THPs are on the LRU, but need to be counted as #small pages.
+                 * We need not scan over tail pages because we don't
+                 * handle each tail page individually in migration.
+                 */
+                if (PageHuge(page) || PageTransCompound(page)) {
+                        struct page *head = compound_head(page);
+                        unsigned int skip_pages;
+
+                        if (PageHuge(page)) {
+                                if (!hugepage_migration_supported(page_hstate(head)))
+                                        return page;
+                        } else if (!PageLRU(head) && !__PageMovable(head)) {
+                                return page;
+                        }
+
+                        skip_pages = compound_nr(head) - (page - head);
+                        iter += skip_pages - 1;
+                        continue;
+                }
+
+                /*
+                 * We can't use page_count without pin a page
+                 * because another CPU can free compound page.
+                 * This check already skips compound tails of THP
+                 * because their page->_refcount is zero at all time.
+                 */
+                if (!page_ref_count(page)) {
+                        if (PageBuddy(page))
+                                iter += (1 << buddy_order(page)) - 1;
+                        continue;
+                }
+
+                /*
+                 * The HWPoisoned page may be not in buddy system, and
+                 * page_count() is not 0.
+                 */
+                if ((flags & MEMORY_OFFLINE) && PageHWPoison(page))
+                        continue;
+
+                /*
+                 * We treat all PageOffline() pages as movable when offlining
+                 * to give drivers a chance to decrement their reference count
+                 * in MEM_GOING_OFFLINE in order to indicate that these pages
+                 * can be offlined as there are no direct references anymore.
+                 * For actually unmovable PageOffline() where the driver does
+                 * not support this, we will fail later when trying to actually
+                 * move these pages that still have a reference count > 0.
+                 * (false negatives in this function only)
+                 */
+                if ((flags & MEMORY_OFFLINE) && PageOffline(page))
+                        continue;
+
+                if (__PageMovable(page) || PageLRU(page))
+                        continue;
+
+                /*
+                 * If there are RECLAIMABLE pages, we need to check
+                 * it.  But now, memory offline itself doesn't call
+                 * shrink_node_slabs() and it still to be fixed.
+                 */
+                return page;
+        }
+        return NULL;
+}
+
+#ifdef CONFIG_CONTIG_ALLOC
+static unsigned long pfn_max_align_down(unsigned long pfn)
+{
+        return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
+                             pageblock_nr_pages) - 1);
+}
+
+static unsigned long pfn_max_align_up(unsigned long pfn)
+{
+        return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
+                                pageblock_nr_pages));
+}
+
+/* [start, end) must belong to a single zone. */
+static int __alloc_contig_migrate_range(struct compact_control *cc,
+                                        unsigned long start, unsigned long end)
+{
+        /* This function is based on compact_zone() from compaction.c. */
+        unsigned int nr_reclaimed;
+        unsigned long pfn = start;
+        unsigned int tries = 0;
+        int ret = 0;
+        struct migration_target_control mtc = {
+                .nid = zone_to_nid(cc->zone),
+                .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
+        };
+
+        migrate_prep();
+
+        while (pfn < end || !list_empty(&cc->migratepages)) {
+                if (fatal_signal_pending(current)) {
+                        ret = -EINTR;
+                        break;
+                }
+
+                if (list_empty(&cc->migratepages)) {
+                        cc->nr_migratepages = 0;
+                        pfn = isolate_migratepages_range(cc, pfn, end);
+                        if (!pfn) {
+                                ret = -EINTR;
+                                break;
+                        }
+                        tries = 0;
+                } else if (++tries == 5) {
+                        ret = ret < 0 ? ret : -EBUSY;
+                        break;
+                }
+
+                nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
+                                                        &cc->migratepages);
+                cc->nr_migratepages -= nr_reclaimed;
+
+                ret = migrate_pages(&cc->migratepages, alloc_migration_target,
+                                NULL, (unsigned long)&mtc, cc->mode, MR_CONTIG_RANGE);
+        }
+        if (ret < 0) {
+                putback_movable_pages(&cc->migratepages);
+                return ret;
+        }
+        return 0;
+}
+
+/**
+ * alloc_contig_range() -- tries to allocate given range of pages
+ * @start:      start PFN to allocate
+ * @end:        one-past-the-last PFN to allocate
+ * @migratetype:        migratetype of the underlaying pageblocks (either
+ *                      #MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
+ *                      in range must have the same migratetype and it must
+ *                      be either of the two.
+ * @gfp_mask:   GFP mask to use during compaction
+ *
+ * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
+ * aligned.  The PFN range must belong to a single zone.
+ *
+ * The first thing this routine does is attempt to MIGRATE_ISOLATE all
+ * pageblocks in the range.  Once isolated, the pageblocks should not
+ * be modified by others.
+ *
+ * Return: zero on success or negative error code.  On success all
+ * pages which PFN is in [start, end) are allocated for the caller and
+ * need to be freed with free_contig_range().
+ */
+int alloc_contig_range(unsigned long start, unsigned long end,
+                       unsigned migratetype, gfp_t gfp_mask)
+{
+        unsigned long outer_start, outer_end;
+        unsigned int order;
+        int ret = 0;
+
+        struct compact_control cc = {
+                .nr_migratepages = 0,
+                .order = -1,
+                .zone = page_zone(pfn_to_page(start)),
+                .mode = MIGRATE_SYNC,
+                .ignore_skip_hint = true,
+                .no_set_skip_hint = true,
+                .gfp_mask = current_gfp_context(gfp_mask),
+                .alloc_contig = true,
+        };
+        INIT_LIST_HEAD(&cc.migratepages);
+
+        /*
+         * What we do here is we mark all pageblocks in range as
+         * MIGRATE_ISOLATE.  Because pageblock and max order pages may
+         * have different sizes, and due to the way page allocator
+         * work, we align the range to biggest of the two pages so
+         * that page allocator won't try to merge buddies from
+         * different pageblocks and change MIGRATE_ISOLATE to some
+         * other migration type.
+         *
+         * Once the pageblocks are marked as MIGRATE_ISOLATE, we
+         * migrate the pages from an unaligned range (ie. pages that
+         * we are interested in).  This will put all the pages in
+         * range back to page allocator as MIGRATE_ISOLATE.
+         *
+         * When this is done, we take the pages in range from page
+         * allocator removing them from the buddy system.  This way
+         * page allocator will never consider using them.
+         *
+         * This lets us mark the pageblocks back as
+         * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
+         * aligned range but not in the unaligned, original range are
+         * put back to page allocator so that buddy can use them.
+         */
+
+        ret = start_isolate_page_range(pfn_max_align_down(start),
+                                       pfn_max_align_up(end), migratetype, 0);
+        if (ret)
+                return ret;
+
+        /*
+         * In case of -EBUSY, we'd like to know which page causes problem.
+         * So, just fall through. test_pages_isolated() has a tracepoint
+         * which will report the busy page.
+         *
+         * It is possible that busy pages could become available before
+         * the call to test_pages_isolated, and the range will actually be
+         * allocated.  So, if we fall through be sure to clear ret so that
+         * -EBUSY is not accidentally used or returned to caller.
+         */
+        ret = __alloc_contig_migrate_range(&cc, start, end);
+        if (ret && ret != -EBUSY)
+                goto done;
+        ret =0;
+
+        /*
+         * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
+         * aligned blocks that are marked as MIGRATE_ISOLATE.  What's
+         * more, all pages in [start, end) are free in page allocator.
+         * What we are going to do is to allocate all pages from
+         * [start, end) (that is remove them from page allocator).
+         *
+         * The only problem is that pages at the beginning and at the
+         * end of interesting range may be not aligned with pages that
+         * page allocator holds, ie. they can be part of higher order
+         * pages.  Because of this, we reserve the bigger range and
+         * once this is done free the pages we are not interested in.
+         *
+         * We don't have to hold zone->lock here because the pages are
+         * isolated thus they won't get removed from buddy.
+         */
+
+        lru_add_drain_all();
+
+        order = 0;
+        outer_start = start;
+        while (!PageBuddy(pfn_to_page(outer_start))) {
+                if (++order >= MAX_ORDER) {
+                        outer_start = start;
+                        break;
+                }
+                outer_start &= ~0UL << order;
+        }
+
+        if (outer_start != start) {
+                order = buddy_order(pfn_to_page(outer_start));
+
+                /*
+                 * outer_start page could be small order buddy page and
+                 * it doesn't include start page. Adjust outer_start
+                 * in this case to report failed page properly
+                 * on tracepoint in test_pages_isolated()
+                 */
+                if (outer_start + (1UL << order) <= start)
+                        outer_start = start;
+        }
+
+        /* Make sure the range is really isolated. */
+        if (test_pages_isolated(outer_start, end, 0)) {
+                pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n",
+                        __func__, outer_start, end);
+                ret = -EBUSY;
+                goto done;
+        }
+
+        /* Grab isolated pages from freelists. */
+        outer_end = isolate_freepages_range(&cc, outer_start, end);
+        if (!outer_end) {
+                ret = -EBUSY;
+                goto done;
+        }
+
+        /* Free head and tail (if any) */
+        if (start != outer_start)
+                free_contig_range(outer_start, start - outer_start);
+        if (end != outer_end)
+                free_contig_range(end, outer_end - end);
+
+done:
+        undo_isolate_page_range(pfn_max_align_down(start),
+                                pfn_max_align_up(end), migratetype);
+        return ret;
+}
+EXPORT_SYMBOL(alloc_contig_range);
+
+static int __alloc_contig_pages(unsigned long start_pfn,
+                                unsigned long nr_pages, gfp_t gfp_mask)
+{
+        unsigned long end_pfn = start_pfn + nr_pages;
+
+        return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
+                                  gfp_mask);
+}
+
+static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
+                                   unsigned long nr_pages)
+{
+        unsigned long i, end_pfn = start_pfn + nr_pages;
+        struct page *page;
+
+        for (i = start_pfn; i < end_pfn; i++) {
+                page = pfn_to_online_page(i);
+                if (!page)
+                        return false;
+
+                if (page_zone(page) != z)
+                        return false;
+
+                if (PageReserved(page))
+                        return false;
+
+                if (page_count(page) > 0)
+                        return false;
+
+                if (PageHuge(page))
+                        return false;
+        }
+        return true;
+}
+
+static bool zone_spans_last_pfn(const struct zone *zone,
+                                unsigned long start_pfn, unsigned long nr_pages)
+{
+        unsigned long last_pfn = start_pfn + nr_pages - 1;
+
+        return zone_spans_pfn(zone, last_pfn);
+}
+
+/**
+ * alloc_contig_pages() -- tries to find and allocate contiguous range of pages
+ * @nr_pages:   Number of contiguous pages to allocate
+ * @gfp_mask:   GFP mask to limit search and used during compaction
+ * @nid:        Target node
+ * @nodemask:   Mask for other possible nodes
+ *
+ * This routine is a wrapper around alloc_contig_range(). It scans over zones
+ * on an applicable zonelist to find a contiguous pfn range which can then be
+ * tried for allocation with alloc_contig_range(). This routine is intended
+ * for allocation requests which can not be fulfilled with the buddy allocator.
+ *
+ * The allocated memory is always aligned to a page boundary. If nr_pages is a
+ * power of two then the alignment is guaranteed to be to the given nr_pages
+ * (e.g. 1GB request would be aligned to 1GB).
+ *
+ * Allocated pages can be freed with free_contig_range() or by manually calling
+ * __free_page() on each allocated page.
+ *
+ * Return: pointer to contiguous pages on success, or NULL if not successful.
+ */
+struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask,
+                                int nid, nodemask_t *nodemask)
+{
+        unsigned long ret, pfn, flags;
+        struct zonelist *zonelist;
+        struct zone *zone;
+        struct zoneref *z;
+
+        zonelist = node_zonelist(nid, gfp_mask);
+        for_each_zone_zonelist_nodemask(zone, z, zonelist,
+                                        gfp_zone(gfp_mask), nodemask) {
+                spin_lock_irqsave(&zone->lock, flags);
+
+                pfn = ALIGN(zone->zone_start_pfn, nr_pages);
+                while (zone_spans_last_pfn(zone, pfn, nr_pages)) {
+                        if (pfn_range_valid_contig(zone, pfn, nr_pages)) {
+                                /*
+                                 * We release the zone lock here because
+                                 * alloc_contig_range() will also lock the zone
+                                 * at some point. If there's an allocation
+                                 * spinning on this lock, it may win the race
+                                 * and cause alloc_contig_range() to fail...
+                                 */
+                                spin_unlock_irqrestore(&zone->lock, flags);
+                                ret = __alloc_contig_pages(pfn, nr_pages,
+                                                        gfp_mask);
+                                if (!ret)
+                                        return pfn_to_page(pfn);
+                                spin_lock_irqsave(&zone->lock, flags);
+                        }
+                        pfn += nr_pages;
+                }
+                spin_unlock_irqrestore(&zone->lock, flags);
+        }
+        return NULL;
+}
+#endif /* CONFIG_CONTIG_ALLOC */
+
+void free_contig_range(unsigned long pfn, unsigned int nr_pages)
+{
+        unsigned int count = 0;
+
+        for (; nr_pages--; pfn++) {
+                struct page *page = pfn_to_page(pfn);
+
+                count += page_count(page) != 1;
+                __free_page(page);
+        }
+        WARN(count != 0, "%d pages are still in use!\n", count);
+}
+EXPORT_SYMBOL(free_contig_range);
+
+/*
+ * The zone indicated has a new number of managed_pages; batch sizes and percpu
+ * page high values need to be recalulated.
+ */
+void __meminit zone_pcp_update(struct zone *zone)
+{
+        mutex_lock(&pcp_batch_high_lock);
+        __zone_pcp_update(zone);
+        mutex_unlock(&pcp_batch_high_lock);
+}
+
+void zone_pcp_reset(struct zone *zone)
+{
+        unsigned long flags;
+        int cpu;
+        struct per_cpu_pageset *pset;
+
+        /* avoid races with drain_pages()  */
+        local_irq_save(flags);
+        if (zone->pageset != &boot_pageset) {
+                for_each_online_cpu(cpu) {
+                        pset = per_cpu_ptr(zone->pageset, cpu);
+                        drain_zonestat(zone, pset);
+                }
+                free_percpu(zone->pageset);
+                zone->pageset = &boot_pageset;
+        }
+        local_irq_restore(flags);
+}
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+/*
+ * All pages in the range must be in a single zone, must not contain holes,
+ * must span full sections, and must be isolated before calling this function.
+ */
+void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
+{
+        unsigned long pfn = start_pfn;
+        struct page *page;
+        struct zone *zone;
+        unsigned int order;
+        unsigned long flags;
+
+        offline_mem_sections(pfn, end_pfn);
+        zone = page_zone(pfn_to_page(pfn));
+        spin_lock_irqsave(&zone->lock, flags);
+        while (pfn < end_pfn) {
+                page = pfn_to_page(pfn);
+                /*
+                 * The HWPoisoned page may be not in buddy system, and
+                 * page_count() is not 0.
+                 */
+                if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
+                        pfn++;
+                        continue;
+                }
+                /*
+                 * At this point all remaining PageOffline() pages have a
+                 * reference count of 0 and can simply be skipped.
+                 */
+                if (PageOffline(page)) {
+                        BUG_ON(page_count(page));
+                        BUG_ON(PageBuddy(page));
+                        pfn++;
+                        continue;
+                }
+
+                BUG_ON(page_count(page));
+                BUG_ON(!PageBuddy(page));
+                order = buddy_order(page);
+                del_page_from_free_list(page, zone, order);
+                pfn += (1 << order);
+        }
+        spin_unlock_irqrestore(&zone->lock, flags);
+}
+#endif
+
+bool is_free_buddy_page(struct page *page)
+{
+        struct zone *zone = page_zone(page);
+        unsigned long pfn = page_to_pfn(page);
+        unsigned long flags;
+        unsigned int order;
+
+        spin_lock_irqsave(&zone->lock, flags);
+        for (order = 0; order < MAX_ORDER; order++) {
+                struct page *page_head = page - (pfn & ((1 << order) - 1));
+
+                if (PageBuddy(page_head) && buddy_order(page_head) >= order)
+                        break;
+        }
+        spin_unlock_irqrestore(&zone->lock, flags);
+
+        return order < MAX_ORDER;
+}
+
+#ifdef CONFIG_MEMORY_FAILURE
+/*
+ * Break down a higher-order page in sub-pages, and keep our target out of
+ * buddy allocator.
+ */
+static void break_down_buddy_pages(struct zone *zone, struct page *page,
+                                   struct page *target, int low, int high,
+                                   int migratetype)
+{
+        unsigned long size = 1 << high;
+        struct page *current_buddy, *next_page;
+
+        while (high > low) {
+                high--;
+                size >>= 1;
+
+                if (target >= &page[size]) {
+                        next_page = page + size;
+                        current_buddy = page;
+                } else {
+                        next_page = page;
+                        current_buddy = page + size;
+                }
+
+                if (set_page_guard(zone, current_buddy, high, migratetype))
+                        continue;
+
+                if (current_buddy != target) {
+                        add_to_free_list(current_buddy, zone, high, migratetype);
+                        set_buddy_order(current_buddy, high);
+                        page = next_page;
+                }
+        }
+}
+
+/*
+ * Take a page that will be marked as poisoned off the buddy allocator.
+ */
+bool take_page_off_buddy(struct page *page)
+{
+        struct zone *zone = page_zone(page);
+        unsigned long pfn = page_to_pfn(page);
+        unsigned long flags;
+        unsigned int order;
+        bool ret = false;
+
+        spin_lock_irqsave(&zone->lock, flags);
+        for (order = 0; order < MAX_ORDER; order++) {
+                struct page *page_head = page - (pfn & ((1 << order) - 1));
+                int page_order = buddy_order(page_head);
+
+                if (PageBuddy(page_head) && page_order >= order) {
+                        unsigned long pfn_head = page_to_pfn(page_head);
+                        int migratetype = get_pfnblock_migratetype(page_head,
+                                                                   pfn_head);
+
+                        del_page_from_free_list(page_head, zone, page_order);
+                        break_down_buddy_pages(zone, page_head, page, 0,
+                                                page_order, migratetype);
+                        if (!is_migrate_isolate(migratetype))
+                                __mod_zone_freepage_state(zone, -1, migratetype);
+                        ret = true;
+                        break;
+                }
+                if (page_count(page_head) > 0)
+                        break;
+        }
+        spin_unlock_irqrestore(&zone->lock, flags);
+        return ret;
+}
+#endif
+
+#ifdef CONFIG_ZONE_DMA
+bool has_managed_dma(void)
+{
+        struct pglist_data *pgdat;
+
+        for_each_online_pgdat(pgdat) {
+                struct zone *zone = &pgdat->node_zones[ZONE_DMA];
+
+                if (managed_zone(zone))
+                        return true;
+        }
+        return false;
+}
+#endif /* CONFIG_ZONE_DMA */