Release 4.13 mm/page_alloc.c

/*
 *  linux/mm/page_alloc.c
 *
 *  Manages the free list, the system allocates free pages here.
 *  Note that kmalloc() lives in slab.c
 *
 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *  Swap reorganised 29.12.95, Stephen Tweedie
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
 *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
 *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
 *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
 *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
 */

#include <linux/stddef.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
#include <linux/jiffies.h>
#include <linux/bootmem.h>
#include <linux/memblock.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/kmemcheck.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/notifier.h>
#include <linux/topology.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/memory_hotplug.h>
#include <linux/nodemask.h>
#include <linux/vmalloc.h>
#include <linux/vmstat.h>
#include <linux/mempolicy.h>
#include <linux/memremap.h>
#include <linux/stop_machine.h>
#include <linux/sort.h>
#include <linux/pfn.h>
#include <linux/backing-dev.h>
#include <linux/fault-inject.h>
#include <linux/page-isolation.h>
#include <linux/page_ext.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/nmi.h>

#include <asm/sections.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
#include "internal.h"

/* 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

#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_);

int _node_numa_mem_[MAX_NUMNODES];
#endif

/* work_structs for global per-cpu drains */

DEFINE_MUTEX(pcpu_drain_mutex);
DEFINE_PER_CPU(struct work_struct, 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);

/* Protect totalram_pages and zone->managed_pages */
static DEFINE_SPINLOCK(managed_page_count_lock);


unsigned long totalram_pages __read_mostly;

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;

/*
 * 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;
}

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static inline void set_pcppage_migratetype(struct page *page, int migratetype)
{
	page->index = migratetype;
}

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#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 pm_mutex held (gfp_allowed_mask also should
 * only be modified with pm_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(&pm_mutex));
	if (saved_gfp_mask) {
		gfp_allowed_mask = saved_gfp_mask;
		saved_gfp_mask = 0;
	}
}

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void pm_restrict_gfp_mask(void)
{
	WARN_ON(!mutex_is_locked(&pm_mutex));
	WARN_ON(saved_gfp_mask);
	saved_gfp_mask = gfp_allowed_mask;
	gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
}

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bool pm_suspended_storage(void)
{
	if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS))
		return false;
	return true;
}
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#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);

/*
 * 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-1] = {
#ifdef CONFIG_ZONE_DMA
	 256,
#endif
#ifdef CONFIG_ZONE_DMA32
	 256,
#endif
#ifdef CONFIG_HIGHMEM
	 32,
#endif
	 32,
};


EXPORT_SYMBOL(totalram_pages);


static char * const zone_names[MAX_NR_ZONES] = {
#ifdef CONFIG_ZONE_DMA
	 "DMA",
#endif
#ifdef CONFIG_ZONE_DMA32
	 "DMA32",
#endif
	 "Normal",
#ifdef CONFIG_HIGHMEM
	 "HighMem",
#endif
	 "Movable",
#ifdef CONFIG_ZONE_DEVICE
	 "Device",
#endif
};


char * const migratetype_names[MIGRATE_TYPES] = {
	"Unmovable",
	"Movable",
	"Reclaimable",
	"HighAtomic",
#ifdef CONFIG_CMA
	"CMA",
#endif
#ifdef CONFIG_MEMORY_ISOLATION
	"Isolate",
#endif
};


compound_page_dtor * const compound_page_dtors[] = {
	NULL,
	free_compound_page,
#ifdef CONFIG_HUGETLB_PAGE
	free_huge_page,
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	free_transhuge_page,
#endif
};


int min_free_kbytes = 1024;

int user_min_free_kbytes = -1;

int watermark_scale_factor = 10;


static unsigned long __meminitdata nr_kernel_pages;

static unsigned long __meminitdata nr_all_pages;

static unsigned long __meminitdata dma_reserve;

#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP

static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];

static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];

static unsigned long __initdata required_kernelcore;

static unsigned long __initdata required_movablecore;

static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];

static bool mirrored_kernelcore;

/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */

int movable_zone;

EXPORT_SYMBOL(movable_zone);
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */

#if MAX_NUMNODES > 1

int nr_node_ids __read_mostly = MAX_NUMNODES;

int nr_online_nodes __read_mostly = 1;

EXPORT_SYMBOL(nr_node_ids);

EXPORT_SYMBOL(nr_online_nodes);
#endif


int page_group_by_mobility_disabled __read_mostly;

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT


static inline void reset_deferred_meminit(pg_data_t *pgdat)
{
	unsigned long max_initialise;
	unsigned long reserved_lowmem;

	/*
         * Initialise at least 2G of a node but also take into account that
         * two large system hashes that can take up 1GB for 0.25TB/node.
         */
	max_initialise = max(2UL << (30 - PAGE_SHIFT),
		(pgdat->node_spanned_pages >> 8));

	/*
         * Compensate the all the memblock reservations (e.g. crash kernel)
         * from the initial estimation to make sure we will initialize enough
         * memory to boot.
         */
	reserved_lowmem = memblock_reserved_memory_within(pgdat->node_start_pfn,
			pgdat->node_start_pfn + max_initialise);
	max_initialise += reserved_lowmem;

	pgdat->static_init_size = min(max_initialise, pgdat->node_spanned_pages);
	pgdat->first_deferred_pfn = ULONG_MAX;
}

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/* 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;
}

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/*
 * Returns false when the remaining initialisation should be deferred until
 * later in the boot cycle when it can be parallelised.
 */


static inline bool update_defer_init(pg_data_t *pgdat,
				unsigned long pfn, unsigned long zone_end,
				unsigned long *nr_initialised)
{
	/* Always populate low zones for address-contrained allocations */
	if (zone_end < pgdat_end_pfn(pgdat))
		return true;
	(*nr_initialised)++;
	if ((*nr_initialised > pgdat->static_init_size) &&
	    (pfn & (PAGES_PER_SECTION - 1)) == 0) {
		pgdat->first_deferred_pfn = pfn;
		return false;
	}

	return true;
}
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#else


static inline void reset_deferred_meminit(pg_data_t *pgdat)
{
}

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static inline bool early_page_uninitialised(unsigned long pfn)
{
	return false;
}

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static inline bool update_defer_init(pg_data_t *pgdat,
				unsigned long pfn, unsigned long zone_end,
				unsigned long *nr_initialised)
{
	return true;
}
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#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 __pfn_to_section(pfn)->pageblock_flags;
#else
	return page_zone(page)->pageblock_flags;
#endif /* CONFIG_SPARSEMEM */
}

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static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
{
#ifdef CONFIG_SPARSEMEM
	pfn &= (PAGES_PER_SECTION-1);
	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
#else
	pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
#endif /* CONFIG_SPARSEMEM */
}

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/**
 * 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
 * @end_bitidx: The last bit of interest to retrieve
 * @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 end_bitidx,
					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];
	bitidx += end_bitidx;
	return (word >> (BITS_PER_LONG - bitidx - 1)) & mask;
}

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unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
					unsigned long end_bitidx,
					unsigned long mask)
{
	return __get_pfnblock_flags_mask(page, pfn, end_bitidx, mask);
}

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static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
{
	return __get_pfnblock_flags_mask(page, pfn, PB_migrate_end, MIGRATETYPE_MASK);
}

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/**
 * 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
 * @end_bitidx: The last bit of interest
 * @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 end_bitidx,
					unsigned long mask)
{
	unsigned long *bitmap;
	unsigned long bitidx, word_bitidx;
	unsigned long old_word, word;

	BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);

	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);

	bitidx += end_bitidx;
	mask <<= (BITS_PER_LONG - bitidx - 1);
	flags <<= (BITS_PER_LONG - bitidx - 1);

	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;
	}
}

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void set_pageblock_migratetype(struct page *page, int migratetype)
{
	if (unlikely(page_group_by_mobility_disabled &&
		     migratetype < MIGRATE_PCPTYPES))
		migratetype = MIGRATE_UNMOVABLE;

	set_pageblock_flags_group(page, (unsigned long)migratetype,
					PB_migrate, PB_migrate_end);
}

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#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;
}

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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;
}
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/*
 * 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;
}
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#else


static inline int __maybe_unused bad_range(struct zone *zone, struct page *page)
{
	return 0;
}
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JoonSoo Kim
5
23.81%
1
33.33%
Matthias Kaehlcke
1
4.76%
1
33.33%
Total
21
100.00%
3
100.00%

#endif



static void bad_page(struct page *page, const char *reason,
		unsigned long bad_flags)
{
	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);
	bad_flags &= page->flags;
	if (bad_flags)
		pr_alert("bad because of flags: %#lx(%pGp)\n",
						bad_flags, &bad_flags);
	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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
120
72.73%
1
25.00%
Stanislaw Gruszka
23
13.94%
1
25.00%
JoonSoo Kim
22
13.33%
2
50.00%
Total
165
100.00%
4
100.00%

/*
 * 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)
{
	__free_pages_ok(page, compound_order(page));
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Stanislaw Gruszka
10
50.00%
1
25.00%
JoonSoo Kim
7
35.00%
2
50.00%
Mel Gorman
3
15.00%
1
25.00%
Total
20
100.00%
4
100.00%



void prep_compound_page(struct page *page, unsigned int order)
{
	int i;
	int nr_pages = 1 << order;

	set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
	set_compound_order(page, 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);
	}
	atomic_set(compound_mapcount_ptr(page), -1);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
60
61.22%
1
20.00%
Kamezawa Hiroyuki
20
20.41%
1
20.00%
Stanislaw Gruszka
7
7.14%
1
20.00%
Hugh Dickins
6
6.12%
1
20.00%
JoonSoo Kim
5
5.10%
1
20.00%
Total
98
100.00%
5
100.00%

#ifdef CONFIG_DEBUG_PAGEALLOC

unsigned int _debug_guardpage_minorder;

bool _debug_pagealloc_enabled __read_mostly
			= IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);

EXPORT_SYMBOL(_debug_pagealloc_enabled);

bool _debug_guardpage_enabled __read_mostly;



static int __init early_debug_pagealloc(char *buf)
{
	if (!buf)
		return -EINVAL;
	return kstrtobool(buf, &_debug_pagealloc_enabled);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
16
55.17%
2
33.33%
Nicholas Piggin
6
20.69%
1
16.67%
Kamezawa Hiroyuki
3
10.34%
1
16.67%
Minfei Huang
3
10.34%
1
16.67%
Stanislaw Gruszka
1
3.45%
1
16.67%
Total
29
100.00%
6
100.00%

early_param("debug_pagealloc", early_debug_pagealloc);



static bool need_debug_guardpage(void)
{
	/* If we don't use debug_pagealloc, we don't need guard page */
	if (!debug_pagealloc_enabled())
		return false;

	if (!debug_guardpage_minorder())
		return false;

	return true;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
18
60.00%
1
33.33%
JoonSoo Kim
9
30.00%
1
33.33%
Stanislaw Gruszka
3
10.00%
1
33.33%
Total
30
100.00%
3
100.00%



static void init_debug_guardpage(void)
{
	if (!debug_pagealloc_enabled())
		return;

	if (!debug_guardpage_minorder())
		return;

	_debug_guardpage_enabled = true;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
16
61.54%
1
25.00%
JoonSoo Kim
7
26.92%
1
25.00%
Stanislaw Gruszka
2
7.69%
1
25.00%
Nicholas Piggin
1
3.85%
1
25.00%
Total
26
100.00%
4
100.00%


struct page_ext_operations debug_guardpage_ops = {
	.need = need_debug_guardpage,
	.init = init_debug_guardpage,
};



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;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
51
86.44%
2
50.00%
Kamezawa Hiroyuki
4
6.78%
1
25.00%
Weijie Yang
4
6.78%
1
25.00%
Total
59
100.00%
4
100.00%

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)
{
	struct page_ext *page_ext;

	if (!debug_guardpage_enabled())
		return false;

	if (order >= debug_guardpage_minorder())
		return false;

	page_ext = lookup_page_ext(page);
	if (unlikely(!page_ext))
		return false;

	__set_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);

	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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
45
41.28%
4
17.39%
JoonSoo Kim
25
22.94%
3
13.04%
Andrew Morton
9
8.26%
4
17.39%
Yang Shi
8
7.34%
1
4.35%
Linus Torvalds (pre-git)
6
5.50%
4
17.39%
Vlastimil Babka
4
3.67%
1
4.35%
Kirill A. Shutemov
3
2.75%
1
4.35%
Cody P Schafer
3
2.75%
1
4.35%
Corrado Zoccolo
2
1.83%
1
4.35%
Kamezawa Hiroyuki
2
1.83%
1
4.35%
Hugh Dickins
1
0.92%
1
4.35%
Sasha Levin
1
0.92%
1
4.35%
Total
109
100.00%
23
100.00%



static inline void clear_page_guard(struct zone *zone, struct page *page,
				unsigned int order, int migratetype)
{
	struct page_ext *page_ext;

	if (!debug_guardpage_enabled())
		return;

	page_ext = lookup_page_ext(page);
	if (unlikely(!page_ext))
		return;

	__clear_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);

	set_page_private(page, 0);
	if (!is_migrate_isolate(migratetype))
		__mod_zone_freepage_state(zone, (1 << order), migratetype);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
53
58.89%
1
7.14%
Stanislaw Gruszka
12
13.33%
1
7.14%
Yang Shi
9
10.00%
1
7.14%
Linus Torvalds (pre-git)
4
4.44%
3
21.43%
Kamezawa Hiroyuki
2
2.22%
1
7.14%
Dave Hansen
2
2.22%
1
7.14%
Andy Whitcroft
2
2.22%
1
7.14%
Bartlomiej Zolnierkiewicz
2
2.22%
1
7.14%
Sasha Levin
1
1.11%
1
7.14%
Martin J. Bligh
1
1.11%
1
7.14%
Andrew Morton
1
1.11%
1
7.14%
Cho KyongHo
1
1.11%
1
7.14%
Total
90
100.00%
14
100.00%

#else

struct page_ext_operations debug_guardpage_ops;


static inline bool set_page_guard(struct zone *zone, struct page *page,
			unsigned int order, int migratetype) { return false; }
Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
19
70.37%
1
25.00%
JoonSoo Kim
6
22.22%
1
25.00%
Martin J. Bligh
1
3.70%
1
25.00%
Kamezawa Hiroyuki
1
3.70%
1
25.00%
Total
27
100.00%
4
100.00%



static inline void clear_page_guard(struct zone *zone, struct page *page,
				unsigned int order, int migratetype) {}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
23
100.00%
1
100.00%
Total
23
100.00%
1
100.00%

#endif



static inline void set_page_order(struct page *page, unsigned int order)
{
	set_page_private(page, order);
	__SetPageBuddy(page);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
23
82.14%
1
25.00%
Kamezawa Hiroyuki
2
7.14%
1
25.00%
Linus Torvalds (pre-git)
2
7.14%
1
25.00%
Stanislaw Gruszka
1
3.57%
1
25.00%
Total
28
100.00%
4
100.00%



static inline void rmv_page_order(struct page *page)
{
	__ClearPageBuddy(page);
	set_page_private(page, 0);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
19
79.17%
1
25.00%
Dave Hansen
2
8.33%
1
25.00%
Linus Torvalds (pre-git)
2
8.33%
1
25.00%
Kamezawa Hiroyuki
1
4.17%
1
25.00%
Total
24
100.00%
4
100.00%

/*
 * This function checks whether a page is free && is the buddy
 * we can do coalesce a page and its buddy if
 * (a) the buddy is not in a hole (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 ->_mapcount
 * PAGE_BUDDY_MAPCOUNT_VALUE.
 * Setting, clearing, and testing _mapcount PAGE_BUDDY_MAPCOUNT_VALUE is
 * serialized by zone->lock.
 *
 * For recording page's order, we use page_private(page).
 */


static inline int page_is_buddy(struct page *page, struct page *buddy,
							unsigned int order)
{
	if (page_is_guard(buddy) && page_order(buddy) == order) {
		if (page_zone_id(page) != page_zone_id(buddy))
			return 0;

		VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);

		return 1;
	}

	if (PageBuddy(buddy) && page_order(buddy) == order) {
		/*
                 * 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 0;

		VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);

		return 1;
	}
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
79
67.52%
1
14.29%
Vlastimil Babka
15
12.82%
1
14.29%
Corrado Zoccolo
14
11.97%
1
14.29%
Kamezawa Hiroyuki
5
4.27%
1
14.29%
Linus Torvalds (pre-git)
3
2.56%
2
28.57%
Andrew Morton
1
0.85%
1
14.29%
Total
117
100.00%
7
100.00%

/*
 * 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 _mapcount
 * PAGE_BUDDY_MAPCOUNT_VALUE. 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)
{
	unsigned long combined_pfn;
	unsigned long uninitialized_var(buddy_pfn);
	struct page *buddy;
	unsigned int max_order;

	max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);

	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 - 1) {
		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 {
			list_del(&buddy->lru);
			zone->free_area[order].nr_free--;
			rmv_page_order(buddy);
		}
		combined_pfn = buddy_pfn & pfn;
		page = page + (combined_pfn - pfn);
		pfn = combined_pfn;
		order++;
	}
	if (max_order < MAX_ORDER) {
		/* 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++;
		goto continue_merging;
	}

done_merging:
	set_page_order(page, order);

	/*
         * 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
         */
	if ((order < MAX_ORDER-2) && pfn_valid_within(buddy_pfn)) {
		struct page *higher_page, *higher_buddy;
		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);
		if (pfn_valid_within(buddy_pfn) &&
		    page_is_buddy(higher_page, higher_buddy, order + 1)) {
			list_add_tail(&page->lru,
				&zone->free_area[order].free_list[migratetype]);
			goto out;
		}
	}

	list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
out:
	zone->free_area[order].nr_free++;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
342
69.51%
10
38.46%
Vlastimil Babka
45
9.15%
3
11.54%
Andrew Morton
30
6.10%
2
7.69%
Dave Hansen
26
5.28%
1
3.85%
JoonSoo Kim
18
3.66%
2
7.69%
Nicholas Piggin
8
1.63%
2
7.69%
Bartlomiej Zolnierkiewicz
6
1.22%
1
3.85%
Christoph Lameter
5
1.02%
1
3.85%
Tony Luck
5
1.02%
1
3.85%
Namhyung Kim
3
0.61%
1
3.85%
Kirill A. Shutemov
3
0.61%
1
3.85%
Daisuke Nishimura
1
0.20%
1
3.85%
Total
492
100.00%
26
100.00%

/*
 * 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
55
68.75%
1
16.67%
Kirill A. Shutemov
25
31.25%
5
83.33%
Total
80
100.00%
6
100.00%



static void free_pages_check_bad(struct page *page)
{
	const char *bad_reason;
	unsigned long bad_flags;

	bad_reason = NULL;
	bad_flags = 0;

	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 & PAGE_FLAGS_CHECK_AT_FREE)) {
		bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
		bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
	}
#ifdef CONFIG_MEMCG
	if (unlikely(page->mem_cgroup))
		bad_reason = "page still charged to cgroup";
#endif
	bad_page(page, bad_reason, bad_flags);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
86
67.72%
1
25.00%
Kirill A. Shutemov
41
32.28%
3
75.00%
Total
127
100.00%
4
100.00%



static inline int free_pages_check(struct page *page)
{
	if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE)))
		return 0;

	/* Something has gone sideways, find it */
	free_pages_check_bad(page);
	return 1;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Robin Holt
19
52.78%
1
50.00%
Mel Gorman
17
47.22%
1
50.00%
Total
36
100.00%
2
100.00%



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 is compound_mapcount() */
		if (unlikely(compound_mapcount(page))) {
			bad_page(page, "nonzero compound_mapcount", 0);
			goto out;
		}
		break;
	case 2:
		/*
                 * the second tail page: ->mapping is
                 * page_deferred_list().next -- ignore value.
                 */
		break;
	default:
		if (page->mapping != TAIL_MAPPING) {
			bad_page(page, "corrupted mapping in tail page", 0);
			goto out;
		}
		break;
	}
	if (unlikely(!PageTail(page))) {
		bad_page(page, "PageTail not set", 0);
		goto out;
	}
	if (unlikely(compound_head(page) != head_page)) {
		bad_page(page, "compound_head not consistent", 0);
		goto out;
	}
	ret = 0;
out:
	page->mapping = NULL;
	clear_compound_head(page);
	return ret;
}

Contributors
Person
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Mel Gorman
187
100.00%
1
100.00%
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187
100.00%
1
100.00%



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);
	kmemcheck_free_shadow(page, order);

	/*
         * 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(free_pages_check(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, order);
	if (check_free)
		bad += free_pages_check(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);
	}
	arch_free_page(page, order);
	kernel_poison_pages(page, 1 << order, 0);
	kernel_map_pages(page, 1 << order, 0);
	kasan_free_pages(page, order);

	return true;
}

Contributors
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Mel Gorman
261
88.47%
2
33.33%
Vladimir Davydov
17
5.76%
1
16.67%
Kirill A. Shutemov
9
3.05%
1
16.67%
seokhoon.yoon
7
2.37%
1
16.67%
MinChan Kim
1
0.34%
1
16.67%
Total
295
100.00%
6
100.00%

#ifdef CONFIG_DEBUG_VM


static inline bool free_pcp_prepare(struct page *page)
{
	return free_pages_prepare(page, 0, true);
}

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Mel Gorman
22
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22
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static inline bool bulkfree_pcp_prepare(struct page *page)
{
	return false;
}
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Mel Gorman
15
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15
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#else


static bool free_pcp_prepare(struct page *page)
{
	return free_pages_prepare(page, 0, false);
}

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Mel Gorman
21
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21
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static bool bulkfree_pcp_prepare(struct page *page)
{
	return free_pages_check(page);
}
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Mel Gorman
17
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17
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#endif /* CONFIG_DEBUG_VM */

/*
 * 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;
	bool isolated_pageblocks;

	spin_lock(&zone->lock);
	isolated_pageblocks = has_isolate_pageblock(zone);

	while (count) {
		struct page *page;
		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 {
			int mt;	/* migratetype of the to-be-freed page */

			page = list_last_entry(list, struct page, lru);
			/* must delete as __free_one_page list manipulates */
			list_del(&page->lru);

			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);

			if (bulkfree_pcp_prepare(page))
				continue;

			__free_one_page(page, page_to_pfn(page), zone, 0, mt);
			trace_mm_page_pcpu_drain(page, 0, mt);
		} while (--count && --batch_free && !list_empty(list));
	}
	spin_unlock(&zone->lock);
}

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Mel Gorman
204
89.87%
4
57.14%
Nathan Zimmer
11
4.85%
1
14.29%
Robin Holt
8
3.52%
1
14.29%
Kirill A. Shutemov
4
1.76%
1
14.29%
Total
227
100.00%
7
100.00%



static void free_one_page(struct zone *zone,
				struct page *page, unsigned long pfn,
				unsigned int order,
				int migratetype)
{
	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);
	spin_unlock(&zone->lock);
}

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Mel Gorman
57
69.51%
3
33.33%
Andrew Morton
11
13.41%
1
11.11%
Andrea Arcangeli
4
4.88%
1
11.11%
Kirill A. Shutemov
4
4.88%
1
11.11%
Yu Zhao
3
3.66%
1
11.11%
Andrey Ryabinin
2
2.44%
1
11.11%
Nicholas Piggin
1
1.22%
1
11.11%
Total
82
100.00%
9
100.00%



static void __meminit __init_single_page(struct page *page, unsigned long pfn,
				unsigned long zone, int nid)
{
	set_page_links(page, zone, nid, pfn);
	init_page_count(page);
	page_mapcount_reset(page);
	page_cpupid_reset_last(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
}

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Mel Gorman
56
67.47%
3
27.27%
Motohiro Kosaki
13
15.66%
1
9.09%
Nicholas Piggin
9
10.84%
3
27.27%
Linus Torvalds (pre-git)
3
3.61%
3
27.27%
Andrew Morton
2
2.41%
1
9.09%
Total
83
100.00%
11
100.00%



static void __meminit __init_single_pfn(unsigned long pfn, unsigned long zone,
					int nid)
{
	return __init_single_page(pfn_to_page(pfn), pfn, zone, nid);
}

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Mel Gorman
26
78.79%
2
66.67%
David Howells
7
21.21%
1
33.33%
Total
33
100.00%
3
100.00%

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT


static void 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_pfn(pfn, zid, nid);
}
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Mel Gorman
69
72.63%
1
16.67%
David Howells
18
18.95%
1
16.67%
Yinghai Lu
3
3.16%
1
16.67%
Nicholas Piggin
3
3.16%
1
16.67%
Johannes Weiner
1
1.05%
1
16.67%
Jiang Liu
1
1.05%
1
16.67%
Total
95
100.00%
6
100.00%

#else


static inline void init_reserved_page(unsigned long pfn)
{
}
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Mel Gorman
10
100.00%
2
100.00%
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10
100.00%
2
100.00%

#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);

			SetPageReserved(page);
		}
	}
}

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Mel Gorman
78
97.50%
3
75.00%
Stefan Bader
2
2.50%
1
25.00%
Total
80
100.00%
4
100.00%



static void __free_pages_ok(struct page *page, unsigned int order)
{
	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);
	local_irq_restore(flags);
}

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Mel Gorman
88
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5
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88
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5
100.00%



static void __init __free_pages_boot_core(struct page *page, unsigned int order)
{
	unsigned int nr_pages = 1 << order;
	struct page *p = page;
	unsigned int loop;

	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);

	page_zone(page)->managed_pages += nr_pages;
	set_page_refcounted(page);
	__free_pages(page, order);
}

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Mel Gorman
114
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4
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114
100.00%
4
100.00%

#if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \
	defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)


static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;



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;
}
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Mel Gorman
54
100.00%
5
100.00%
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54
100.00%
5
100.00%

#endif

#ifdef CONFIG_NODES_SPAN_OTHER_NODES

static inline bool __meminit __maybe_unused

meminit_pfn_in_nid(unsigned long pfn, int node,
		   struct mminit_pfnnid_cache *state)
{
	int nid;

	nid = __early_pfn_to_nid(pfn, state);
	if (nid >= 0 && nid != node)
		return false;
	return true;
}

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Mel Gorman
42
85.71%
2
40.00%
Nicolai Stange
4
8.16%
1
20.00%
JoonSoo Kim
2
4.08%
1
20.00%
Matthias Kaehlcke
1
2.04%
1
20.00%
Total
49
100.00%
5
100.00%

/* Only safe to use early in boot when initialisation is single-threaded */


static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
{
	return meminit_pfn_in_nid(pfn, node, &early_pfnnid_cache);
}

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26
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2
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26
100.00%
2
100.00%

#else



static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
{
	return true;
}
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Mel Gorman
18
100.00%
1
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18
100.00%
1
100.00%


static inline bool __meminit  __maybe_unused

meminit_pfn_in_nid(unsigned long pfn, int node,
		   struct mminit_pfnnid_cache *state)
{
	return true;
}
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Mel Gorman
23
95.83%
1
50.00%
Matthias Kaehlcke
1
4.17%
1
50.00%
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24
100.00%
2
100.00%

#endif




void __init __free_pages_bootmem(struct page *page, unsigned long pfn,
							unsigned int order)
{
	if (early_page_uninitialised(pfn))
		return;
	return __free_pages_boot_core(page, order);
}

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Mel Gorman
30
85.71%
1
50.00%
JoonSoo Kim
5
14.29%
1
50.00%
Total
35
100.00%
2
100.00%

/*
 * 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;
}

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Mel Gorman
64
61.54%
1
16.67%
Michal Nazarewicz
29
27.88%
2
33.33%
Michal Hocko
9
8.65%
1
16.67%
Jiang Liu
1
0.96%
1
16.67%
Marek Szyprowski
1
0.96%
1
16.67%
Total
104
100.00%
6
100.00%



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;
	}

	/* We confirm that there is no hole */
	zone->contiguous = true;
}

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Mel Gorman
55
64.71%
1
9.09%
Linus Torvalds (pre-git)
13
15.29%
3
27.27%
Andrew Morton
7
8.24%
2
18.18%
Stanislaw Gruszka
6
7.06%
1
9.09%
Nicholas Piggin
2
2.35%
2
18.18%
Bartlomiej Zolnierkiewicz
1
1.18%
1
9.09%
Sasha Levin
1
1.18%
1
9.09%
Total
85
100.00%
11
100.00%



void clear_zone_contiguous(struct zone *zone)
{
	zone->contiguous = false;
}

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Mel Gorman
11
68.75%
1
50.00%
Andrew Morton
5
31.25%
1
50.00%
Total
16
100.00%
2
100.00%

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT


static void __init deferred_free_range(struct page *page,
					unsigned long pfn, int nr_pages)
{
	int i;

	if (!page)
		return;

	/* 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_boot_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_boot_core(page, 0);
	}
}

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Mel Gorman
58
51.33%
2
18.18%
Xishi Qiu
29
25.66%
1
9.09%
Dave Hansen
10
8.85%
1
9.09%
Andrew Morton
7
6.19%
3
27.27%
Naoya Horiguchi
4
3.54%
1
9.09%
Kirill A. Shutemov
3
2.65%
1
9.09%
Fengguang Wu
1
0.88%
1
9.09%
Hugh Dickins
1
0.88%
1
9.09%
Total
113
100.00%
11
100.00%

/* 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);
}

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Mel Gorman
17
70.83%
1
50.00%
Laura Abbott
7
29.17%
1
50.00%
Total
24
100.00%
2
100.00%

/* Initialise remaining memory on a node */


static int __init deferred_init_memmap(void *data)
{
	pg_data_t *pgdat = data;
	int nid = pgdat->node_id;
	struct mminit_pfnnid_cache nid_init_state = { };
	unsigned long start = jiffies;
	unsigned long nr_pages = 0;
	unsigned long walk_start, walk_end;
	int i, zid;
	struct zone *zone;
	unsigned long first_init_pfn = pgdat->first_deferred_pfn;
	const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);

	if (first_init_pfn == ULONG_MAX) {
		pgdat_init_report_one_done();
		return 0;
	}

	/* Bind memory initialisation thread to a local node if possible */
	if (!cpumask_empty(cpumask))
		set_cpus_allowed_ptr(current, cpumask);

	/* 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;

	/* 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;
	}

	for_each_mem_pfn_range(i, nid, &walk_start, &walk_end, NULL) {
		unsigned long pfn, end_pfn;
		struct page *page = NULL;
		struct page *free_base_page = NULL;
		unsigned long free_base_pfn = 0;
		int nr_to_free = 0;

		end_pfn = min(walk_end, zone_end_pfn(zone));
		pfn = first_init_pfn;
		if (pfn < walk_start)
			pfn = walk_start;
		if (pfn < zone->zone_start_pfn)
			pfn = zone->zone_start_pfn;

		for (; pfn < end_pfn; pfn++) {
			if (!pfn_valid_within(pfn))
				goto free_range;

			/*
                         * Ensure pfn_valid is checked every
                         * pageblock_nr_pages for memory holes
                         */
			if ((pfn & (pageblock_nr_pages - 1)) == 0) {
				if (!pfn_valid(pfn)) {
					page = NULL;
					goto free_range;
				}
			}

			if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state)) {
				page = NULL;
				goto free_range;
			}

			/* Minimise pfn page lookups and scheduler checks */
			if (page && (pfn & (pageblock_nr_pages - 1)) != 0) {
				page++;
			} else {
				nr_pages += nr_to_free;
				deferred_free_range(free_base_page,
						free_base_pfn, nr_to_free);
				free_base_page = NULL;
				free_base_pfn = nr_to_free = 0;

				page = pfn_to_page(pfn);
				cond_resched();
			}

			if (page->flags) {
				VM_BUG_ON(page_zone(page) != zone);
				goto free_range;
			}

			__init_single_page(page, pfn, zid, nid);
			if (!free_base_page) {
				free_base_page = page;
				free_base_pfn = pfn;
				nr_to_free = 0;
			}
			nr_to_free++;

			/* Where possible, batch up pages for a single free */
			continue;
free_range:
			/* Free the current block of pages to allocator */
			nr_pages += nr_to_free;
			deferred_free_range(free_base_page, free_base_pfn,
								nr_to_free);
			free_base_page = NULL;
			free_base_pfn = nr_to_free = 0;
		}
		/* Free the last block of pages to allocator */
		nr_pages += nr_to_free;
		deferred_free_range(free_base_page, free_base_pfn, nr_to_free);

		first_init_pfn = max(end_pfn, first_init_pfn);
	}

	/* Sanity check that the next zone really is unpopulated */
	WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));

	pr_info("node %d initialised, %lu pages in %ums\n", nid, nr_pages,
					jiffies_to_msecs(jiffies - start));

	pgdat_init_report_one_done();
	return 0;
}
Contributors
Person
Tokens
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Mel Gorman
456
84.92%
2
11.11%
Fengguang Wu
19
3.54%
1
5.56%
Xishi Qiu
17
3.17%
1
5.56%
Anisse Astier
10
1.86%
1
5.56%
Laura Abbott
8
1.49%
2
11.11%
Nicholas Piggin
6
1.12%
2
11.11%
Andrew Morton
4
0.74%
2
11.11%
Vlastimil Babka
4
0.74%
1
5.56%
Geliang Tang
3
0.56%
1
5.56%
JoonSoo Kim
3
0.56%
1
5.56%
Hugh Dickins
3
0.56%
1
5.56%
Linus Torvalds
2
0.37%
1
5.56%
Andrey Ryabinin
1
0.19%
1
5.56%
Michal Hocko
1
0.19%
1
5.56%
Total
537
100.00%
18
100.00%

#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */



void __init page_alloc_init_late(void)
{
	struct zone *zone;

#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
	int nid;

	/* 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);

	/* Reinit limits that are based on free pages after the kernel is up */
	files_maxfiles_init();
#endif
#ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
	/* Discard memblock private memory */
	memblock_discard();
#endif

	for_each_populated_zone(zone)
		set_zone_contiguous(zone);
}

Contributors
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CommitProp
Mel Gorman
63
75.00%
2
40.00%
JoonSoo Kim
11
13.10%
1
20.00%
Pavel Tatashin
9
10.71%
1
20.00%
Michal Nazarewicz
1
1.19%
1
20.00%
Total
84
100.00%
5
100.00%

#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);
}
Contributors
Person
Tokens
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Commits
CommitProp
Mel Gorman
114
95.00%
2
50.00%
Adam Litke
5
4.17%
1
25.00%
Sasha Levin
1
0.83%
1
25.00%
Total
120
100.00%
4
100.00%

#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, struct free_area *area,
	int migratetype)
{
	unsigned long size = 1 << high;

	while (high > low) {
		area--;
		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;

		list_add(&page[size].lru, &area->free_list[migratetype]);
		area->nr_free++;
		set_page_order(&page[size], high);
	}
}

Contributors
Person
Tokens
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Commits
CommitProp
Mel Gorman
126
96.18%
2
50.00%
Cody P Schafer
3
2.29%
1
25.00%
JoonSoo Kim
2
1.53%
1
25.00%
Total
131
100.00%
4
100.00%



static void check_new_page_bad(struct page *page)
{
	const char *bad_reason = NULL;
	unsigned long bad_flags = 0;

	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 _count";
	if (unlikely(page->flags & __PG_HWPOISON)) {
		bad_reason = "HWPoisoned (hardware-corrupted)";
		bad_flags = __PG_HWPOISON;
		/* Don't complain about hwpoisoned pages */
		page_mapcount_reset(page); /* remove PageBuddy */
		return;
	}
	if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
		bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
		bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
	}
#ifdef CONFIG_MEMCG
	if (unlikely(page->mem_cgroup))
		bad_reason = "page still charged to cgroup";
#endif
	bad_page(page, bad_reason, bad_flags);
}

Contributors
Person
Tokens
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CommitProp
Mel Gorman
103
67.76%
2
33.33%
Srivatsa S. Bhat
20
13.16%
1
16.67%
JoonSoo Kim
15
9.87%
1
16.67%
Naoya Horiguchi
8
5.26%
1
16.67%
Vlastimil Babka
6
3.95%
1
16.67%
Total
152
100.00%
6
100.00%

/*
 * 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;
}

Contributors
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Tokens
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Vlastimil Babka
33
89.19%
1
33.33%
JoonSoo Kim
3
8.11%
1
33.33%
Mel Gorman
1
2.70%
1
33.33%
Total
37
100.00%
3
100.00%



static inline bool free_pages_prezeroed(void)
{
	return IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) &&
		page_poisoning_enabled();
}

Contributors
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Mel Gorman
14
77.78%
1
25.00%
JoonSoo Kim
2
11.11%
1
25.00%
Srivatsa S. Bhat
1
5.56%
1
25.00%
Vinayak Menon
1
5.56%
1
25.00%
Total
18
100.00%
4
100.00%

#ifdef CONFIG_DEBUG_VM


static bool check_pcp_refill(struct page *page)
{
	return false;
}

Contributors
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Mel Gorman
14
100.00%
1
100.00%
Total
14
100.00%
1
100.00%



static bool check_new_pcp(struct page *page)
{
	return check_new_page(page);
}
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Mel Gorman
17
100.00%
1
100.00%
Total
17
100.00%
1
100.00%

#else


static bool check_pcp_refill(struct page *page)
{
	return check_new_page(page);
}
Contributors
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Mel Gorman
17
100.00%
1
100.00%
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17
100.00%
1
100.00%



static bool check_new_pcp(struct page *page)
{
	return false;
}
Contributors
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Mel Gorman
14
100.00%
1
100.00%
Total
14
100.00%
1
100.00%

#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;
}

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Mel Gorman
62
100.00%
3
100.00%
Total
62
100.00%
3
100.00%



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);
	kernel_map_pages(page, 1 << order, 1);
	kernel_poison_pages(page, 1 << order, 1);
	kasan_alloc_pages(page, order);
	set_page_owner(page, order, gfp_flags);
}

Contributors
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JoonSoo Kim
75
100.00%
1
100.00%
Total
75
100.00%
1
100.00%



static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
							unsigned int alloc_flags)
{
	int i;

	post_alloc_hook(page, order, gfp_flags);

	if (!free_pages_prezeroed() && (gfp_flags & __GFP_ZERO))
		for (i = 0; i < (1 << order); i++)
			clear_highpage(page + i);

	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);
}

Contributors
Person
Tokens
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CommitProp
Mel Gorman
102
97.14%
3
60.00%
JoonSoo Kim
2
1.90%
1
20.00%
Vinayak Menon
1
0.95%
1
20.00%
Total
105
100.00%
5
100.00%

/*
 * Go through the free lists for the given migratetype and remove
 * the smallest available page from the freelists
 */

static inline

struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
						int migratetype)
{
	unsigned int current_order;
	struct free_area *area;
	struct page *page;

	/* Find a page of the appropriate size in the preferred list */
	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
		area = &(zone->free_area[current_order]);
		page = list_first_entry_or_null(&area->free_list[migratetype],
							struct page, lru);
		if (!page)
			continue;
		list_del(&page->lru);
		rmv_page_order(page);
		area->nr_free--;
		expand(zone, page, order, current_order, area, migratetype);
		set_pcppage_migratetype(page, migratetype);
		return page;
	}

	return NULL;
}


Contributors
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Tokens
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Mel Gorman
125
93.98%
2
66.67%
Geliang Tang
8
6.02%
1
33.33%
Total
133
100.00%
3
100.00%

/*
 * 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][4] = {
	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_TYPES },
	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_TYPES },
	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, 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 struct page *__rmqueue_cma_fallback(struct zone *zone,
					unsigned int order)
{
	return __rmqueue_smallest(zone, order, MIGRATE_CMA);
}
Contributors
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Mel Gorman
27
100.00%
2
100.00%
Total
27
100.00%
2
100.00%

#else


static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
					unsigned int order) { return NULL; }
Contributors
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Mel Gorman
21
100.00%
4
100.00%
Total
21
100.00%
4
100.00%

#endif

/*
 * Move the free pages in a range to the free lists of the requested type.
 * Note that start_page and end_pages are not aligned on a pageblock
 * boundary. If alignment is required, use move_freepages_block()
 */


static int move_freepages(struct zone *zone,
			  struct page *start_page, struct page *end_page,
			  int migratetype, int *num_movable)
{
	struct page *page;
	unsigned int order;
	int pages_moved = 0;

#ifndef CONFIG_HOLES_IN_ZONE
	/*
         * page_zone is not safe to call in this context when
         * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
         * anyway as we check zone boundaries in move_freepages_block().
         * Remove at a later date when no bug reports exist related to
         * grouping pages by mobility
         */
	VM_BUG_ON(page_zone(start_page) != page_zone(end_page));
#endif

	if (num_movable)
		*num_movable = 0;

	for (page = start_page; page <= end_page;) {
		if (!pfn_valid_within(page_to_pfn(page))) {
			page++;
			continue;
		}

		/* Make sure we are not inadvertently changing nodes */
		VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);

		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)++;

			page++;
			continue;
		}

		order = page_order(page);
		list_move(&page->lru,
			  &zone->free_area[order].free_list[migratetype]);
		page += 1 << order;
		pages_moved += 1 << order;
	}

	return pages_moved;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
135
68.88%
6
54.55%
Vlastimil Babka
39
19.90%
2
18.18%
Ard Biesheuvel
16
8.16%
1
9.09%
JoonSoo Kim
5
2.55%
1
9.09%
Srivatsa S. Bhat
1
0.51%
1
9.09%
Total
196
100.00%
11
100.00%



int move_freepages_block(struct zone *zone, struct page *page,
				int migratetype, int *num_movable)
{
	unsigned long start_pfn, end_pfn;
	struct page *start_page, *end_page;

	start_pfn = page_to_pfn(page);
	start_pfn = start_pfn & ~(pageblock_nr_pages-1);
	start_page = pfn_to_page(start_pfn);
	end_page = start_page + pageblock_nr_pages - 1;
	end_pfn = start_pfn + pageblock_nr_pages - 1;

	/* Do not cross zone boundaries */
	if (!zone_spans_pfn(zone, start_pfn))
		start_page = page;
	if (!zone_spans_pfn(zone, end_pfn))
		return 0;

	return move_freepages(zone, start_page, end_page, migratetype,
								num_movable);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
93
78.15%
4
33.33%
JoonSoo Kim
10
8.40%
1
8.33%
Vlastimil Babka
6
5.04%
1
8.33%
Linus Torvalds (pre-git)
5
4.20%
3
25.00%
Andrew Morton
4
3.36%
2
16.67%
Nicholas Piggin
1
0.84%
1
8.33%
Total
119
100.00%
12
100.00%



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;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
35
76.09%
4
66.67%
Andrew Morton
9
19.57%
1
16.67%
Nicholas Piggin
2
4.35%
1
16.67%
Total
46
100.00%
6
100.00%

/*
 * 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
41
87.23%
2
50.00%
Linus Torvalds (pre-git)
3
6.38%
1
25.00%
Bartlomiej Zolnierkiewicz
3
6.38%
1
25.00%
Total
47
100.00%
4
100.00%

/*
 * 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,
					int start_type, bool whole_block)
{
	unsigned int current_order = page_order(page);
	struct free_area *area;
	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;
	}

	/* 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:
	area = &zone->free_area[current_order];
	list_move(&page->lru, &area->free_list[start_type]);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Vlastimil Babka
130
61.90%
2
18.18%
Mel Gorman
49
23.33%
1
9.09%
Christoph Lameter
22
10.48%
5
45.45%
Michal Nazarewicz
3
1.43%
1
9.09%
Motohiro Kosaki
3
1.43%
1
9.09%
Cody P Schafer
3
1.43%
1
9.09%
Total
210
100.00%
11
100.00%

/*
 * 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 (list_empty(&area->free_list[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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
100
80.65%
1
14.29%
Rusty Russell
14
11.29%
1
14.29%
David Rientjes
4
3.23%
1
14.29%
Nicholas Piggin
2
1.61%
1
14.29%
Vlastimil Babka
2
1.61%
1
14.29%
Christoph Lameter
2
1.61%
2
28.57%
Total
124
100.00%
7
100.00%

/*
 * 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 / 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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
107
76.98%
1
20.00%
Vlastimil Babka
22
15.83%
2
40.00%
Christoph Lameter
6
4.32%
1
20.00%
Xishi Qiu
4
2.88%
1
20.00%
Total
139
100.00%
5
100.00%

/*
 * 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->high_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 = list_first_entry_or_null(
					&area->free_list[MIGRATE_HIGHATOMIC],
					struct page, lru);
			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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
129
58.37%
1
11.11%
MinChan Kim
34
15.38%
3
33.33%
Gilad Ben-Yossef
28
12.67%
1
11.11%
Vlastimil Babka
23
10.41%
2
22.22%
Christoph Lameter
6
2.71%
1
11.11%
Xishi Qiu
1
0.45%
1
11.11%
Total
221
100.00%
9
100.00%

/*
 * 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 inline bool

__rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
{
	struct free_area *area;
	int current_order;
	struct page *page;
	int fallback_mt;
	bool can_steal;

	/*
         * 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 >= 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 = list_first_entry(&area->free_list[fallback_mt],
							struct page, lru);

	steal_suitable_fallback(zone, page, start_migratetype, can_steal);

	trace_mm_page_alloc_extfrag(page, order, current_order,
		start_migratetype, fallback_mt);

	return true;

}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
93
41.89%
1
8.33%
Vlastimil Babka
91
40.99%
2
16.67%
Pavel Machek
18
8.11%
3
25.00%
Rafael J. Wysocki
7
3.15%
1
8.33%
Andrew Morton
5
2.25%
2
16.67%
Geliang Tang
4
1.80%
1
8.33%
JoonSoo Kim
3
1.35%
1
8.33%
Rusty Russell
1
0.45%
1
8.33%
Total
222
100.00%
12
100.00%

/*
 * Do the hard work of removing an element from the buddy allocator.
 * Call me with the zone->lock already held.
 */


static struct page *__rmqueue(struct zone *zone, unsigned int order,
				int migratetype)
{
	struct page *page;

retry:
	page = __rmqueue_smallest(zone, order, migratetype);
	if (unlikely(!page)) {
		if (migratetype == MIGRATE_MOVABLE)
			page = __rmqueue_cma_fallback(zone, order);

		if (!page && __rmqueue_fallback(zone, order, migratetype))
			goto retry;
	}

	trace_mm_page_alloc_zone_locked(page, order, migratetype);
	return page;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
67
72.83%
4
44.44%
Andrew Morton
12
13.04%
1
11.11%
Vlastimil Babka
7
7.61%
1
11.11%
Hugh Dickins
3
3.26%
1
11.11%
Nicholas Piggin
2
2.17%
1
11.11%
Motohiro Kosaki
1
1.09%
1
11.11%
Total
92
100.00%
9
100.00%

/*
 * 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, bool cold)
{
	int i, alloced = 0;

	spin_lock(&zone->lock);
	for (i = 0; i < count; ++i) {
		struct page *page = __rmqueue(zone, order, migratetype);
		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 callers and
                 * list and the list head then moves forward. From the callers
                 * perspective, the linked list is ordered by page number in
                 * some conditions. This is useful for IO devices that can
                 * merge IO requests if the physical pages are ordered
                 * properly.
                 */
		if (likely(!cold))
			list_add(&page->lru, list);
		else
			list_add_tail(&page->lru, list);
		list = &page->lru;
		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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
144
77.84%
6
46.15%
Christoph Lameter
25
13.51%
3
23.08%
Andrew Morton
12
6.49%
1
7.69%
Cody P Schafer
2
1.08%
1
7.69%
Nicholas Piggin
1
0.54%
1
7.69%
MinChan Kim
1
0.54%
1
7.69%
Total
185
100.00%
13
100.00%

#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);
		pcp->count -= to_drain;
	}
	local_irq_restore(flags);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
56
72.73%
1
50.00%
Konstantin Khlebnikov
21
27.27%
1
50.00%
Total
77
100.00%
2
100.00%

#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);
		pcp->count = 0;
	}
	local_irq_restore(flags);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
53
64.63%
1
16.67%
Nicholas Piggin
15
18.29%
1
16.67%
JoonSoo Kim
10
12.20%
2
33.33%
Vegard Nossum
3
3.66%
1
16.67%
Sasha Levin
1
1.22%
1
16.67%
Total
82
100.00%
6
100.00%

/*
 * 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);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
27
96.43%
3
75.00%
Michal Nazarewicz
1
3.57%
1
25.00%
Total
28
100.00%
4
100.00%

/*
 * 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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
33
100.00%
2
100.00%
Total
33
100.00%
2
100.00%



static void drain_local_pages_wq(struct work_struct *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(NULL);
	preempt_enable();
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
16
69.57%
1
50.00%
Michal Hocko
7
30.43%
1
50.00%
Total
23
100.00%
2
100.00%

/*
 * 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;

	/* Workqueues cannot recurse */
	if (current->flags & PF_WQ_WORKER)
		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 work_struct *work = per_cpu_ptr(&pcpu_drain, cpu);
		INIT_WORK(work, drain_local_pages_wq);
		queue_work_on(cpu, mm_percpu_wq, work);
	}
	for_each_cpu(cpu, &cpus_with_pcps)
		flush_work(per_cpu_ptr(&pcpu_drain, cpu));

	mutex_unlock(&pcpu_drain_mutex);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
219
94.40%
4
80.00%
Michal Hocko
13
5.60%
1
20.00%
Total
232
100.00%
5
100.00%

#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);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
114
53.77%
6
31.58%
Andrew Morton
37
17.45%
2
10.53%
Chen Yu
36
16.98%
1
5.26%
Pavel Machek
9
4.25%
2
10.53%
Christoph Lameter
8
3.77%
3
15.79%
Nicholas Piggin
5
2.36%
3
15.79%
Michal Hocko
2
0.94%
1
5.26%
David Shaohua Li
1
0.47%
1
5.26%
Total
212
100.00%
19
100.00%

#endif /* CONFIG_PM */

/*
 * Free a 0-order page
 * cold == true ? free a cold page : free a hot page
 */


void free_hot_cold_page(struct page *page, bool cold)
{
	struct zone *zone = page_zone(page);
	struct per_cpu_pages *pcp;
	unsigned long flags;
	unsigned long pfn = page_to_pfn(page);
	int migratetype;

	if (!free_pcp_prepare(page))
		return;

	migratetype = get_pfnblock_migratetype(page, pfn);
	set_pcppage_migratetype(page, migratetype);
	local_irq_save(flags);
	__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);
			goto out;
		}
		migratetype = MIGRATE_MOVABLE;
	}

	pcp = &this_cpu_ptr(zone->pageset)->pcp;
	if (!cold)
		list_add(&page->lru, &pcp->lists[migratetype]);
	else
		list_add_tail(&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);
		pcp->count -= batch;
	}

out:
	local_irq_restore(flags);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
194
88.18%
7
53.85%
Johannes Weiner
13
5.91%
3
23.08%
Andrew Morton
8
3.64%
1
7.69%
Motohiro Kosaki
4
1.82%
1
7.69%
Xishi Qiu
1
0.45%
1
7.69%
Total
220
100.00%
13
100.00%

/*
 * Free a list of 0-order pages
 */


void free_hot_cold_page_list(struct list_head *list, bool cold)
{
	struct page *page, *next;

	list_for_each_entry_safe(page, next, list, lru) {
		trace_mm_page_free_batched(page, cold);
		free_hot_cold_page(page, cold);
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
36
76.60%
1
25.00%
Nicholas Piggin
5
10.64%
1
25.00%
Andrew Morton
5
10.64%
1
25.00%
Andi Kleen
1
2.13%
1
25.00%
Total
47
100.00%
4
100.00%

/*
 * 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);

#ifdef CONFIG_KMEMCHECK
	/*
         * Split shadow pages too, because free(page[0]) would
         * otherwise free the whole shadow.
         */
	if (kmemcheck_page_is_tracked(page))
		split_page(virt_to_page(page[0].shadow), order);
#endif

	for (i = 1; i < (1 << order); i++)
		set_page_refcounted(page + i);
	split_page_owner(page, order);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
76
78.35%
1
12.50%
Nicholas Piggin
6
6.19%
1
12.50%
Akinobu Mita
6
6.19%
2
25.00%
Sasha Levin
3
3.09%
1
12.50%
Andrew Morton
3
3.09%
1
12.50%
JoonSoo Kim
2
2.06%
1
12.50%
Don Mullis
1
1.03%
1
12.50%
Total
97
100.00%
8
100.00%


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 = min_wmark_pages(zone) + (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 */
	list_del(&page->lru);
	zone->free_area[order].nr_free--;
	rmv_page_order(page);

	/*
         * 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
170
81.34%
1
12.50%
Akinobu Mita
28
13.40%
2
25.00%
Vlastimil Babka
4
1.91%
2
25.00%
Xishi Qiu
4
1.91%
1
12.50%
MinChan Kim
2
0.96%
1
12.50%
zhong jiang
1
0.48%
1
12.50%
Total
209
100.00%
8
100.00%

/*
 * 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 zone_stat_item local_stat = NUMA_LOCAL;

	if (z->node != numa_node_id())
		local_stat = NUMA_OTHER;

	if (z->node == preferred_zone->node)
		__inc_zone_state(z, NUMA_HIT);
	else {
		__inc_zone_state(z, NUMA_MISS);
		__inc_zone_state(preferred_zone, NUMA_FOREIGN);
	}
	__inc_zone_state(z, local_stat);
#endif
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
57
69.51%
1
33.33%
Michal Hocko
16
19.51%
1
33.33%
Akinobu Mita
9
10.98%
1
33.33%
Total
82
100.00%
3
100.00%

/* Remove page from the per-cpu list, caller must protect the list */


static struct page *__rmqueue_pcplist(struct zone *zone, int migratetype,
			bool cold, 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, cold);
			if (unlikely(list_empty(list)))
				return NULL;
		}

		if (cold)
			page = list_last_entry(list, struct page, lru);
		else
			page = list_first_entry(list, struct page, lru);

		list_del(&page->lru);
		pcp->count--;
	} while (check_new_pcp(page));

	return page;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
113
84.96%
6
75.00%
Nicholas Piggin
11
8.27%
1
12.50%
Vlastimil Babka
9
6.77%
1
12.50%
Total
133
100.00%
8
100.00%

/* Lock and remove page from the per-cpu list */


static struct page *rmqueue_pcplist(struct zone *preferred_zone,
			struct zone *zone, unsigned int order,
			gfp_t gfp_flags, int migratetype)
{
	struct per_cpu_pages *pcp;
	struct list_head *list;
	bool cold = ((gfp_flags & __GFP_COLD) != 0);
	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, cold, pcp, list);
	if (page) {
		__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
		zone_statistics(preferred_zone, zone);
	}
	local_irq_restore(flags);
	return page;
}

Contributors
Person
Tokens
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CommitProp
Mel Gorman
137
100.00%
3
100.00%
Total
137
100.00%
3
100.00%

/*
 * 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)) {
		page = rmqueue_pcplist(preferred_zone, zone, order,
				gfp_flags, migratetype);
		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;
		if (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);
	} 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:
	VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
	return page;

failed:
	local_irq_restore(flags);
	return NULL;
}

Contributors
Person
Tokens
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Commits
CommitProp
Mel Gorman
250
99.21%
7
87.50%
Nicholas Piggin
2
0.79%
1
12.50%
Total
252
100.00%
8
100.00%

#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);
}
Contributors
Person
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Mel Gorman
12
54.55%
2
66.67%
David Rientjes
10
45.45%
1
33.33%
Total
22
100.00%
3
100.00%

__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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
67
88.16%
1
50.00%
Johannes Weiner
9
11.84%
1
50.00%
Total
76
100.00%
2
100.00%

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS



static int __init fail_page_alloc_debugfs(void)
{
	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
	struct dentry *dir;

	dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
					&fail_page_alloc.attr);
	if (IS_ERR(dir))
		return PTR_ERR(dir);

	if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
				&fail_page_alloc.ignore_gfp_reclaim))
		goto fail;
	if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir,
				&fail_page_alloc.ignore_gfp_highmem))
		goto fail;
	if (!debugfs_create_u32("min-order", mode, dir,
				&fail_page_alloc.min_order))
		goto fail;

	return 0;
fail:
	debugfs_remove_recursive(dir);

	return -ENOMEM;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
121
97.58%
2
50.00%
Johannes Weiner
2
1.61%
1
25.00%
David Rientjes
1
0.81%
1
25.00%
Total
124
100.00%
4
100.00%


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;
}

Contributors
Person
Tokens
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CommitProp
Rohit Seth
8
47.06%
1
33.33%
Mel Gorman
7
41.18%
1
33.33%
Martin Hicks
2
11.76%
1
33.33%
Total
17
100.00%
3
100.00%

#endif /* CONFIG_FAIL_PAGE_ALLOC */

/*
 * 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 classzone_idx, unsigned int alloc_flags,
			 long free_pages)
{
	long min = mark;
	int o;
	const bool alloc_harder = (alloc_flags & ALLOC_HARDER);

	/* free_pages may go negative - that's OK */
	free_pages -= (1 << order) - 1;

	if (alloc_flags & ALLOC_HIGH)
		min -= min / 2;

	/*
         * 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))
		free_pages -= z->nr_reserved_highatomic;
	else
		min -= min / 4;

#ifdef CONFIG_CMA
	/* If allocation can't use CMA areas don't use free CMA pages */
	if (!(alloc_flags & ALLOC_CMA))
		free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
#endif

	/*
         * 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[classzone_idx])
		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;

		if (alloc_harder)
			return true;

		for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
			if (!list_empty(&area->free_list[mt]))
				return true;
		}

#ifdef CONFIG_CMA
		if ((alloc_flags & ALLOC_CMA) &&
		    !list_empty(&area->free_list[MIGRATE_CMA])) {
			return true;
		}
#endif
	}
	return false;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
223
88.14%
7
43.75%
Johannes Weiner
13
5.14%
3
18.75%
Christoph Lameter
6
2.37%
2
12.50%
Nicholas Piggin
4
1.58%
1
6.25%
David Rientjes
3
1.19%
1
6.25%
Rohit Seth
3
1.19%
1
6.25%
Martin Hicks
1
0.40%
1
6.25%
Total
253
100.00%
16
100.00%



bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
		      int classzone_idx, unsigned int alloc_flags)
{
	return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
					zone_page_state(z, NR_FREE_PAGES));
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
44
95.65%
2
50.00%
Nicholas Piggin
1
2.17%
1
25.00%
Rohit Seth
1
2.17%
1
25.00%
Total
46
100.00%
4
100.00%



static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
		unsigned long mark, int classzone_idx, unsigned int alloc_flags)
{
	long free_pages = zone_page_state(z, NR_FREE_PAGES);
	long cma_pages = 0;

#ifdef CONFIG_CMA
	/* If allocation can't use CMA areas don't use free CMA pages */
	if (!(alloc_flags & ALLOC_CMA))
		cma_pages = zone_page_state(z, NR_FREE_CMA_PAGES);
#endif

	/*
         * Fast check for order-0 only. If this fails then the reserves
         * need to be calculated. There is a corner case where the check
         * passes but only the high-order atomic reserve are free. If
         * the caller is !atomic then it'll uselessly search the free
         * list. That corner case is then slower but it is harmless.
         */
	if (!order && (free_pages - cma_pages) > mark + z->lowmem_reserve[classzone_idx])
		return true;

	return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
					free_pages);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
100
94.34%
3
50.00%
Vlastimil Babka
4
3.77%
1
16.67%
Christoph Lameter
1
0.94%
1
16.67%
Rohit Seth
1
0.94%
1
16.67%
Total
106
100.00%
6
100.00%



bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
			unsigned long mark, int classzone_idx)
{
	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, classzone_idx, 0,
								free_pages);
}

Contributors
Person
Tokens
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Commits
CommitProp
Mel Gorman
64
94.12%
3
50.00%
Martin Hicks
3
4.41%
2
33.33%
Vlastimil Babka
1
1.47%
1
16.67%
Total
68
100.00%
6
100.00%

#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)) <=
				RECLAIM_DISTANCE;
}
Contributors
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Tokens
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CommitProp
Mel Gorman
27
84.38%
1
33.33%
Dave Hansen
4
12.50%
1
33.33%
Gavin Shan
1
3.12%
1
33.33%
Total
32
100.00%
3
100.00%

#else	/* CONFIG_NUMA */


static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
{
	return true;
}
Contributors
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Mel Gorman
18
94.74%
1
50.00%
Dave Hansen
1
5.26%
1
50.00%
Total
19
100.00%
2
100.00%

#endif	/* CONFIG_NUMA */

/*
 * get_page_from_freelist goes through the zonelist trying to allocate
 * a page.
 */

static struct page *

get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
						const struct alloc_context *ac)
{
	struct zoneref *z = ac->preferred_zoneref;
	struct zone *zone;
	struct pglist_data *last_pgdat_dirty_limit = NULL;

	/*
         * Scan zonelist, looking for a zone with enough free.
         * See also __cpuset_node_allowed() comment in kernel/cpuset.c.
         */
	for_next_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_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;
			}
		}

		mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
		if (!zone_watermark_fast(zone, order, mark,
				       ac_classzone_idx(ac), alloc_flags)) {
			int ret;

			/* 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_classzone_idx(ac), 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;
		}
	}

	return NULL;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
249
77.57%
12
38.71%
Vlastimil Babka
22
6.85%
6
19.35%
Michal Hocko
17
5.30%
3
9.68%
Linus Torvalds (pre-git)
9
2.80%
1
3.23%
Linus Torvalds
6
1.87%
2
6.45%
Christoph Lameter
6
1.87%
1
3.23%
David Rientjes
5
1.56%
1
3.23%
Martin Hicks
2
0.62%
1
3.23%
Johannes Weiner
2
0.62%
1
3.23%
Andrew Morton
1
0.31%
1
3.23%
Rik Van Riel
1
0.31%
1
3.23%
Al Viro
1
0.31%
1
3.23%
Total
321
100.00%
31
100.00%

/*
 * Large machines with many possible nodes should not always dump per-node
 * meminfo in irq context.
 */


static inline bool should_suppress_show_mem(void)
{
	bool ret = false;

#if NODES_SHIFT > 8
	ret = in_interrupt();
#endif
	return ret;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
29
100.00%
3
100.00%
Total
29
100.00%
3
100.00%



static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask)
{
	unsigned int filter = SHOW_MEM_FILTER_NODES;
	static DEFINE_RATELIMIT_STATE(show_mem_rs, HZ, 1);

	if (should_suppress_show_mem() || !__ratelimit(&show_mem_rs))
		return;

	/*
         * 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 (test_thread_flag(TIF_MEMDIE) ||
		    (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);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
71
71.00%
3
42.86%
Michal Hocko
27
27.00%
2
28.57%
Marek Szyprowski
1
1.00%
1
14.29%
Andrew Morton
1
1.00%
1
14.29%
Total
100
100.00%
7
100.00%



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, DEFAULT_RATELIMIT_INTERVAL,
				      DEFAULT_RATELIMIT_BURST);

	if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs))
		return;

	pr_warn("%s: ", current->comm);

	va_start(args, fmt);
	vaf.fmt = fmt;
	vaf.va = &args;
	pr_cont("%pV", &vaf);
	va_end(args);

	pr_cont(", mode:%#x(%pGg), nodemask=", gfp_mask, &gfp_mask);
	if (nodemask)
		pr_cont("%*pbl\n", nodemask_pr_args(nodemask));
	else
		pr_cont("(null)\n");

	cpuset_print_current_mems_allowed();

	dump_stack();
	warn_alloc_show_mem(gfp_mask, nodemask);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Michal Hocko
72
52.55%
4
44.44%
Mel Gorman
43
31.39%
2
22.22%
David Rientjes
18
13.14%
1
11.11%
Rohit Seth
3
2.19%
1
11.11%
Marek Szyprowski
1
0.73%
1
11.11%
Total
137
100.00%
9
100.00%


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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Michal Hocko
63
92.65%
1
50.00%
Marek Szyprowski
5
7.35%
1
50.00%
Total
68
100.00%
2
100.00%


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.
         */
	if (gfp_mask & __GFP_RETRY_MAYFAIL)
		goto out;
	/* The OOM killer does not needlessly kill tasks for lowmem */
	if (ac->high_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.
         */

	/* The OOM killer may not free memory on a specific node */
	if (gfp_mask & __GFP_THISNODE)
		goto out;

	/* Exhausted what can be done so it's blamo 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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
161
65.98%
5
27.78%
Marek Szyprowski
26
10.66%
1
5.56%
Michal Hocko
18
7.38%
3
16.67%
Linus Torvalds (pre-git)
8
3.28%
2
11.11%
Johannes Weiner
8
3.28%
1
5.56%
Vlastimil Babka
7
2.87%
2
11.11%
Tetsuo Handa
6
2.46%
1
5.56%
Vladimir Davydov
5
2.05%
1
5.56%
Rohit Seth
4
1.64%
1
5.56%
Andrew Morton
1
0.41%
1
5.56%
Total
244
100.00%
18
100.00%

/*
 * 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;
	unsigned int noreclaim_flag;

	if (!order)
		return NULL;

	noreclaim_flag = memalloc_noreclaim_save();
	*compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
									prio);
	memalloc_noreclaim_restore(noreclaim_flag);

	if (*compact_result <= COMPACT_INACTIVE)
		return NULL;

	/*
         * At least in one zone compaction wasn't deferred or skipped, so let's
         * count a compaction stall
         */
	count_vm_event(COMPACTSTALL);

	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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
108
68.79%
6
42.86%
Peter Zijlstra
17
10.83%
1
7.14%
Vlastimil Babka
15
9.55%
3
21.43%
Michal Hocko
10
6.37%
2
14.29%
Andrea Arcangeli
4
2.55%
1
7.14%
Bartlomiej Zolnierkiewicz
3
1.91%
1
7.14%
Total
157
100.00%
14
100.00%


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;

	/*
         * 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 do not retry if the given zonelist is not suitable for
         * compaction.
         */
	if (compaction_withdrawn(compact_result)) {
		ret = compaction_zonelist_suitable(ac, order, alloc_flags);
		goto out;
	}

	/*
         * !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;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Vlastimil Babka
143
71.86%
3
60.00%
Michal Hocko
56
28.14%
2
40.00%
Total
199
100.00%
5
100.00%

#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;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
33
76.74%
2
40.00%
Michal Hocko
8
18.60%
2
40.00%
Vlastimil Babka
2
4.65%
1
20.00%
Total
43
100.00%
5
100.00%


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->high_zoneidx,
					ac->nodemask) {
		if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
					ac_classzone_idx(ac), alloc_flags))
			return true;
	}
	return false;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Michal Hocko
93
96.88%
3
60.00%
Vlastimil Babka
3
3.12%
2
40.00%
Total
96
100.00%
5
100.00%

#endif /* CONFIG_COMPACTION */

/* Perform direct synchronous page reclaim */

static int

__perform_reclaim(gfp_t gfp_mask, unsigned int order,
					const struct alloc_context *ac)
{
	struct reclaim_state reclaim_state;
	int progress;
	unsigned int noreclaim_flag;

	cond_resched();

	/* We now go into synchronous reclaim */
	cpuset_memory_pressure_bump();
	noreclaim_flag = memalloc_noreclaim_save();
	lockdep_set_current_reclaim_state(gfp_mask);
	reclaim_state.reclaimed_slab = 0;
	current->reclaim_state = &reclaim_state;

	progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
								ac->nodemask);

	current->reclaim_state = NULL;
	lockdep_clear_current_reclaim_state();
	memalloc_noreclaim_restore(noreclaim_flag);

	cond_resched();

	return progress;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
73
75.26%
9
52.94%
Vlastimil Babka
16
16.49%
3
17.65%
Rohit Seth
2
2.06%
1
5.88%
Andrew Morton
2
2.06%
1
5.88%
Johannes Weiner
2
2.06%
1
5.88%
Peter Zijlstra
1
1.03%
1
5.88%
Linus Torvalds (pre-git)
1
1.03%
1
5.88%
Total
97
100.00%
17
100.00%

/* 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 them and try again
         */
	if (!page && !drained) {
		unreserve_highatomic_pageblock(ac, false);
		drain_all_pages(NULL);
		drained = true;
		goto retry;
	}

	return page;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
74
63.25%
2
15.38%
Linus Torvalds (pre-git)
15
12.82%
2
15.38%
Michal Hocko
10
8.55%
2
15.38%
David Rientjes
4
3.42%
1
7.69%
Kirill Korotaev
4
3.42%
1
7.69%
Vlastimil Babka
2
1.71%
1
7.69%
MinChan Kim
2
1.71%
1
7.69%
Rohit Seth
2
1.71%
1
7.69%
Linus Torvalds
2
1.71%
1
7.69%
Andrew Morton
2
1.71%
1
7.69%
Total
117
100.00%
13
100.00%



static void wake_all_kswapds(unsigned int order, const struct alloc_context *ac)
{
	struct zoneref *z;
	struct zone *zone;
	pg_data_t *last_pgdat = NULL;

	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
					ac->high_zoneidx, ac->nodemask) {
		if (last_pgdat != zone->zone_pgdat)
			wakeup_kswapd(zone, order, ac->high_zoneidx);
		last_pgdat = zone->zone_pgdat;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
71
100.00%
6
100.00%
Total
71
100.00%
6
100.00%


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 to save a branch. */
	BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);

	/*
         * The caller may dip into page reserves a bit more if the caller
         * cannot run direct reclaim, or if the caller has realtime scheduling
         * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
         * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
         */
	alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);

	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;

#ifdef CONFIG_CMA
	if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
		alloc_flags |= ALLOC_CMA;
#endif
	return alloc_flags;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Mel Gorman
86
76.79%
4
57.14%
Vlastimil Babka
24
21.43%
2
28.57%
David Rientjes
2
1.79%
1
14.29%
Total
112
100.00%
7
100.00%



bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
{
	if (unlikely(gfp_mask & __GFP_NOMEMALLOC