1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/mm/page_alloc.c
   4 *
   5 *  Manages the free list, the system allocates free pages here.
   6 *  Note that kmalloc() lives in slab.c
   7 *
   8 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   9 *  Swap reorganised 29.12.95, Stephen Tweedie
  10 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
  11 *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
  12 *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
  13 *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
  14 *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
  15 *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
  16 */
  17
  18#include <linux/stddef.h>
  19#include <linux/mm.h>
  20#include <linux/highmem.h>
  21#include <linux/swap.h>
  22#include <linux/interrupt.h>
  23#include <linux/pagemap.h>
  24#include <linux/jiffies.h>
  25#include <linux/memblock.h>
  26#include <linux/compiler.h>
  27#include <linux/kernel.h>
  28#include <linux/kasan.h>
 
  29#include <linux/module.h>
  30#include <linux/suspend.h>
  31#include <linux/pagevec.h>
  32#include <linux/blkdev.h>
  33#include <linux/slab.h>
  34#include <linux/ratelimit.h>
  35#include <linux/oom.h>
  36#include <linux/topology.h>
  37#include <linux/sysctl.h>
  38#include <linux/cpu.h>
  39#include <linux/cpuset.h>
  40#include <linux/memory_hotplug.h>
  41#include <linux/nodemask.h>
  42#include <linux/vmalloc.h>
  43#include <linux/vmstat.h>
  44#include <linux/mempolicy.h>
  45#include <linux/memremap.h>
  46#include <linux/stop_machine.h>
  47#include <linux/random.h>
  48#include <linux/sort.h>
  49#include <linux/pfn.h>
  50#include <linux/backing-dev.h>
  51#include <linux/fault-inject.h>
  52#include <linux/page-isolation.h>
  53#include <linux/debugobjects.h>
  54#include <linux/kmemleak.h>
  55#include <linux/compaction.h>
  56#include <trace/events/kmem.h>
  57#include <trace/events/oom.h>
  58#include <linux/prefetch.h>
  59#include <linux/mm_inline.h>
 
  60#include <linux/migrate.h>
  61#include <linux/hugetlb.h>
  62#include <linux/sched/rt.h>
  63#include <linux/sched/mm.h>
  64#include <linux/page_owner.h>
  65#include <linux/kthread.h>
  66#include <linux/memcontrol.h>
  67#include <linux/ftrace.h>
  68#include <linux/lockdep.h>
  69#include <linux/nmi.h>
  70#include <linux/psi.h>
  71
  72#include <asm/sections.h>
  73#include <asm/tlbflush.h>
  74#include <asm/div64.h>
  75#include "internal.h"
  76#include "shuffle.h"
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  77
  78/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
  79static DEFINE_MUTEX(pcp_batch_high_lock);
  80#define MIN_PERCPU_PAGELIST_FRACTION	(8)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  81
  82#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
  83DEFINE_PER_CPU(int, numa_node);
  84EXPORT_PER_CPU_SYMBOL(numa_node);
  85#endif
  86
  87DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key);
  88
  89#ifdef CONFIG_HAVE_MEMORYLESS_NODES
  90/*
  91 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
  92 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
  93 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
  94 * defined in <linux/topology.h>.
  95 */
  96DEFINE_PER_CPU(int, _numa_mem_);		/* Kernel "local memory" node */
  97EXPORT_PER_CPU_SYMBOL(_numa_mem_);
  98int _node_numa_mem_[MAX_NUMNODES];
  99#endif
 100
 101/* work_structs for global per-cpu drains */
 102struct pcpu_drain {
 103	struct zone *zone;
 104	struct work_struct work;
 105};
 106DEFINE_MUTEX(pcpu_drain_mutex);
 107DEFINE_PER_CPU(struct pcpu_drain, pcpu_drain);
 108
 109#ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
 110volatile unsigned long latent_entropy __latent_entropy;
 111EXPORT_SYMBOL(latent_entropy);
 112#endif
 113
 114/*
 115 * Array of node states.
 116 */
 117nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
 118	[N_POSSIBLE] = NODE_MASK_ALL,
 119	[N_ONLINE] = { { [0] = 1UL } },
 120#ifndef CONFIG_NUMA
 121	[N_NORMAL_MEMORY] = { { [0] = 1UL } },
 122#ifdef CONFIG_HIGHMEM
 123	[N_HIGH_MEMORY] = { { [0] = 1UL } },
 124#endif
 125	[N_MEMORY] = { { [0] = 1UL } },
 126	[N_CPU] = { { [0] = 1UL } },
 127#endif	/* NUMA */
 128};
 129EXPORT_SYMBOL(node_states);
 130
 131atomic_long_t _totalram_pages __read_mostly;
 132EXPORT_SYMBOL(_totalram_pages);
 133unsigned long totalreserve_pages __read_mostly;
 134unsigned long totalcma_pages __read_mostly;
 135
 136int percpu_pagelist_fraction;
 137gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
 138#ifdef CONFIG_INIT_ON_ALLOC_DEFAULT_ON
 139DEFINE_STATIC_KEY_TRUE(init_on_alloc);
 140#else
 141DEFINE_STATIC_KEY_FALSE(init_on_alloc);
 142#endif
 143EXPORT_SYMBOL(init_on_alloc);
 144
 145#ifdef CONFIG_INIT_ON_FREE_DEFAULT_ON
 146DEFINE_STATIC_KEY_TRUE(init_on_free);
 147#else
 148DEFINE_STATIC_KEY_FALSE(init_on_free);
 149#endif
 150EXPORT_SYMBOL(init_on_free);
 151
 152static int __init early_init_on_alloc(char *buf)
 153{
 154	int ret;
 155	bool bool_result;
 156
 157	if (!buf)
 158		return -EINVAL;
 159	ret = kstrtobool(buf, &bool_result);
 160	if (bool_result && page_poisoning_enabled())
 161		pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_alloc\n");
 162	if (bool_result)
 163		static_branch_enable(&init_on_alloc);
 164	else
 165		static_branch_disable(&init_on_alloc);
 166	return ret;
 167}
 168early_param("init_on_alloc", early_init_on_alloc);
 169
 170static int __init early_init_on_free(char *buf)
 171{
 172	int ret;
 173	bool bool_result;
 174
 175	if (!buf)
 176		return -EINVAL;
 177	ret = kstrtobool(buf, &bool_result);
 178	if (bool_result && page_poisoning_enabled())
 179		pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_free\n");
 180	if (bool_result)
 181		static_branch_enable(&init_on_free);
 182	else
 183		static_branch_disable(&init_on_free);
 184	return ret;
 185}
 186early_param("init_on_free", early_init_on_free);
 187
 188/*
 189 * A cached value of the page's pageblock's migratetype, used when the page is
 190 * put on a pcplist. Used to avoid the pageblock migratetype lookup when
 191 * freeing from pcplists in most cases, at the cost of possibly becoming stale.
 192 * Also the migratetype set in the page does not necessarily match the pcplist
 193 * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
 194 * other index - this ensures that it will be put on the correct CMA freelist.
 195 */
 196static inline int get_pcppage_migratetype(struct page *page)
 197{
 198	return page->index;
 199}
 200
 201static inline void set_pcppage_migratetype(struct page *page, int migratetype)
 202{
 203	page->index = migratetype;
 204}
 205
 206#ifdef CONFIG_PM_SLEEP
 207/*
 208 * The following functions are used by the suspend/hibernate code to temporarily
 209 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
 210 * while devices are suspended.  To avoid races with the suspend/hibernate code,
 211 * they should always be called with system_transition_mutex held
 212 * (gfp_allowed_mask also should only be modified with system_transition_mutex
 213 * held, unless the suspend/hibernate code is guaranteed not to run in parallel
 214 * with that modification).
 215 */
 216
 217static gfp_t saved_gfp_mask;
 218
 219void pm_restore_gfp_mask(void)
 220{
 221	WARN_ON(!mutex_is_locked(&system_transition_mutex));
 222	if (saved_gfp_mask) {
 223		gfp_allowed_mask = saved_gfp_mask;
 224		saved_gfp_mask = 0;
 225	}
 226}
 227
 228void pm_restrict_gfp_mask(void)
 229{
 230	WARN_ON(!mutex_is_locked(&system_transition_mutex));
 231	WARN_ON(saved_gfp_mask);
 232	saved_gfp_mask = gfp_allowed_mask;
 233	gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
 234}
 235
 236bool pm_suspended_storage(void)
 237{
 238	if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS))
 239		return false;
 240	return true;
 241}
 242#endif /* CONFIG_PM_SLEEP */
 243
 244#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
 245unsigned int pageblock_order __read_mostly;
 246#endif
 247
 248static void __free_pages_ok(struct page *page, unsigned int order);
 
 249
 250/*
 251 * results with 256, 32 in the lowmem_reserve sysctl:
 252 *	1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
 253 *	1G machine -> (16M dma, 784M normal, 224M high)
 254 *	NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
 255 *	HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
 256 *	HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA
 257 *
 258 * TBD: should special case ZONE_DMA32 machines here - in those we normally
 259 * don't need any ZONE_NORMAL reservation
 260 */
 261int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = {
 262#ifdef CONFIG_ZONE_DMA
 263	[ZONE_DMA] = 256,
 264#endif
 265#ifdef CONFIG_ZONE_DMA32
 266	[ZONE_DMA32] = 256,
 267#endif
 268	[ZONE_NORMAL] = 32,
 269#ifdef CONFIG_HIGHMEM
 270	[ZONE_HIGHMEM] = 0,
 271#endif
 272	[ZONE_MOVABLE] = 0,
 273};
 274
 275static char * const zone_names[MAX_NR_ZONES] = {
 276#ifdef CONFIG_ZONE_DMA
 277	 "DMA",
 278#endif
 279#ifdef CONFIG_ZONE_DMA32
 280	 "DMA32",
 281#endif
 282	 "Normal",
 283#ifdef CONFIG_HIGHMEM
 284	 "HighMem",
 285#endif
 286	 "Movable",
 287#ifdef CONFIG_ZONE_DEVICE
 288	 "Device",
 289#endif
 290};
 291
 292const char * const migratetype_names[MIGRATE_TYPES] = {
 293	"Unmovable",
 294	"Movable",
 295	"Reclaimable",
 296	"HighAtomic",
 297#ifdef CONFIG_CMA
 298	"CMA",
 299#endif
 300#ifdef CONFIG_MEMORY_ISOLATION
 301	"Isolate",
 302#endif
 303};
 304
 305compound_page_dtor * const compound_page_dtors[] = {
 306	NULL,
 307	free_compound_page,
 308#ifdef CONFIG_HUGETLB_PAGE
 309	free_huge_page,
 310#endif
 311#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 312	free_transhuge_page,
 313#endif
 314};
 315
 316int min_free_kbytes = 1024;
 317int user_min_free_kbytes = -1;
 318#ifdef CONFIG_DISCONTIGMEM
 319/*
 320 * DiscontigMem defines memory ranges as separate pg_data_t even if the ranges
 321 * are not on separate NUMA nodes. Functionally this works but with
 322 * watermark_boost_factor, it can reclaim prematurely as the ranges can be
 323 * quite small. By default, do not boost watermarks on discontigmem as in
 324 * many cases very high-order allocations like THP are likely to be
 325 * unsupported and the premature reclaim offsets the advantage of long-term
 326 * fragmentation avoidance.
 327 */
 328int watermark_boost_factor __read_mostly;
 329#else
 330int watermark_boost_factor __read_mostly = 15000;
 331#endif
 332int watermark_scale_factor = 10;
 333
 334static unsigned long nr_kernel_pages __initdata;
 335static unsigned long nr_all_pages __initdata;
 336static unsigned long dma_reserve __initdata;
 337
 338#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 339static unsigned long arch_zone_lowest_possible_pfn[MAX_NR_ZONES] __initdata;
 340static unsigned long arch_zone_highest_possible_pfn[MAX_NR_ZONES] __initdata;
 341static unsigned long required_kernelcore __initdata;
 342static unsigned long required_kernelcore_percent __initdata;
 343static unsigned long required_movablecore __initdata;
 344static unsigned long required_movablecore_percent __initdata;
 345static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
 346static bool mirrored_kernelcore __meminitdata;
 347
 348/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
 349int movable_zone;
 350EXPORT_SYMBOL(movable_zone);
 351#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 352
 353#if MAX_NUMNODES > 1
 354unsigned int nr_node_ids __read_mostly = MAX_NUMNODES;
 355unsigned int nr_online_nodes __read_mostly = 1;
 356EXPORT_SYMBOL(nr_node_ids);
 357EXPORT_SYMBOL(nr_online_nodes);
 358#endif
 359
 
 
 
 
 
 
 360int page_group_by_mobility_disabled __read_mostly;
 361
 362#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 363/*
 364 * During boot we initialize deferred pages on-demand, as needed, but once
 365 * page_alloc_init_late() has finished, the deferred pages are all initialized,
 366 * and we can permanently disable that path.
 367 */
 368static DEFINE_STATIC_KEY_TRUE(deferred_pages);
 369
 370/*
 371 * Calling kasan_free_pages() only after deferred memory initialization
 372 * has completed. Poisoning pages during deferred memory init will greatly
 373 * lengthen the process and cause problem in large memory systems as the
 374 * deferred pages initialization is done with interrupt disabled.
 375 *
 376 * Assuming that there will be no reference to those newly initialized
 377 * pages before they are ever allocated, this should have no effect on
 378 * KASAN memory tracking as the poison will be properly inserted at page
 379 * allocation time. The only corner case is when pages are allocated by
 380 * on-demand allocation and then freed again before the deferred pages
 381 * initialization is done, but this is not likely to happen.
 382 */
 383static inline void kasan_free_nondeferred_pages(struct page *page, int order)
 384{
 385	if (!static_branch_unlikely(&deferred_pages))
 386		kasan_free_pages(page, order);
 387}
 388
 389/* Returns true if the struct page for the pfn is uninitialised */
 390static inline bool __meminit early_page_uninitialised(unsigned long pfn)
 391{
 392	int nid = early_pfn_to_nid(pfn);
 393
 394	if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn)
 395		return true;
 396
 397	return false;
 398}
 399
 400/*
 401 * Returns true when the remaining initialisation should be deferred until
 402 * later in the boot cycle when it can be parallelised.
 
 
 403 */
 404static bool __meminit
 405defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
 406{
 407	static unsigned long prev_end_pfn, nr_initialised;
 408
 409	/*
 410	 * prev_end_pfn static that contains the end of previous zone
 411	 * No need to protect because called very early in boot before smp_init.
 412	 */
 413	if (prev_end_pfn != end_pfn) {
 414		prev_end_pfn = end_pfn;
 415		nr_initialised = 0;
 416	}
 417
 418	/* Always populate low zones for address-constrained allocations */
 419	if (end_pfn < pgdat_end_pfn(NODE_DATA(nid)))
 420		return false;
 421
 422	/*
 423	 * We start only with one section of pages, more pages are added as
 424	 * needed until the rest of deferred pages are initialized.
 425	 */
 426	nr_initialised++;
 427	if ((nr_initialised > PAGES_PER_SECTION) &&
 428	    (pfn & (PAGES_PER_SECTION - 1)) == 0) {
 429		NODE_DATA(nid)->first_deferred_pfn = pfn;
 430		return true;
 431	}
 432	return false;
 433}
 434#else
 435#define kasan_free_nondeferred_pages(p, o)	kasan_free_pages(p, o)
 436
 437static inline bool early_page_uninitialised(unsigned long pfn)
 438{
 439	return false;
 440}
 441
 442static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
 443{
 444	return false;
 445}
 446#endif
 447
 448/* Return a pointer to the bitmap storing bits affecting a block of pages */
 449static inline unsigned long *get_pageblock_bitmap(struct page *page,
 450							unsigned long pfn)
 451{
 452#ifdef CONFIG_SPARSEMEM
 453	return section_to_usemap(__pfn_to_section(pfn));
 454#else
 455	return page_zone(page)->pageblock_flags;
 456#endif /* CONFIG_SPARSEMEM */
 457}
 458
 459static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
 460{
 461#ifdef CONFIG_SPARSEMEM
 462	pfn &= (PAGES_PER_SECTION-1);
 463	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
 464#else
 465	pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
 466	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
 467#endif /* CONFIG_SPARSEMEM */
 
 468}
 469
 470/**
 471 * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
 472 * @page: The page within the block of interest
 473 * @pfn: The target page frame number
 474 * @end_bitidx: The last bit of interest to retrieve
 475 * @mask: mask of bits that the caller is interested in
 476 *
 477 * Return: pageblock_bits flags
 478 */
 479static __always_inline unsigned long __get_pfnblock_flags_mask(struct page *page,
 480					unsigned long pfn,
 481					unsigned long end_bitidx,
 482					unsigned long mask)
 483{
 484	unsigned long *bitmap;
 485	unsigned long bitidx, word_bitidx;
 486	unsigned long word;
 487
 488	bitmap = get_pageblock_bitmap(page, pfn);
 489	bitidx = pfn_to_bitidx(page, pfn);
 490	word_bitidx = bitidx / BITS_PER_LONG;
 491	bitidx &= (BITS_PER_LONG-1);
 492
 493	word = bitmap[word_bitidx];
 494	bitidx += end_bitidx;
 495	return (word >> (BITS_PER_LONG - bitidx - 1)) & mask;
 496}
 497
 498unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
 499					unsigned long end_bitidx,
 500					unsigned long mask)
 501{
 502	return __get_pfnblock_flags_mask(page, pfn, end_bitidx, mask);
 503}
 504
 505static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
 
 506{
 507	return __get_pfnblock_flags_mask(page, pfn, PB_migrate_end, MIGRATETYPE_MASK);
 508}
 509
 510/**
 511 * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
 512 * @page: The page within the block of interest
 513 * @flags: The flags to set
 514 * @pfn: The target page frame number
 515 * @end_bitidx: The last bit of interest
 516 * @mask: mask of bits that the caller is interested in
 517 */
 518void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
 519					unsigned long pfn,
 520					unsigned long end_bitidx,
 521					unsigned long mask)
 522{
 523	unsigned long *bitmap;
 524	unsigned long bitidx, word_bitidx;
 525	unsigned long old_word, word;
 526
 527	BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
 528	BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits));
 529
 530	bitmap = get_pageblock_bitmap(page, pfn);
 531	bitidx = pfn_to_bitidx(page, pfn);
 532	word_bitidx = bitidx / BITS_PER_LONG;
 533	bitidx &= (BITS_PER_LONG-1);
 534
 535	VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
 536
 537	bitidx += end_bitidx;
 538	mask <<= (BITS_PER_LONG - bitidx - 1);
 539	flags <<= (BITS_PER_LONG - bitidx - 1);
 540
 541	word = READ_ONCE(bitmap[word_bitidx]);
 542	for (;;) {
 543		old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags);
 544		if (word == old_word)
 545			break;
 546		word = old_word;
 547	}
 548}
 549
 550void set_pageblock_migratetype(struct page *page, int migratetype)
 551{
 552	if (unlikely(page_group_by_mobility_disabled &&
 553		     migratetype < MIGRATE_PCPTYPES))
 554		migratetype = MIGRATE_UNMOVABLE;
 555
 556	set_pageblock_flags_group(page, (unsigned long)migratetype,
 557					PB_migrate, PB_migrate_end);
 558}
 559
 560#ifdef CONFIG_DEBUG_VM
 561static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
 562{
 563	int ret = 0;
 564	unsigned seq;
 565	unsigned long pfn = page_to_pfn(page);
 566	unsigned long sp, start_pfn;
 567
 568	do {
 569		seq = zone_span_seqbegin(zone);
 570		start_pfn = zone->zone_start_pfn;
 571		sp = zone->spanned_pages;
 572		if (!zone_spans_pfn(zone, pfn))
 573			ret = 1;
 574	} while (zone_span_seqretry(zone, seq));
 575
 576	if (ret)
 577		pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
 578			pfn, zone_to_nid(zone), zone->name,
 579			start_pfn, start_pfn + sp);
 580
 581	return ret;
 582}
 583
 584static int page_is_consistent(struct zone *zone, struct page *page)
 585{
 586	if (!pfn_valid_within(page_to_pfn(page)))
 587		return 0;
 588	if (zone != page_zone(page))
 589		return 0;
 590
 591	return 1;
 592}
 593/*
 594 * Temporary debugging check for pages not lying within a given zone.
 595 */
 596static int __maybe_unused bad_range(struct zone *zone, struct page *page)
 597{
 598	if (page_outside_zone_boundaries(zone, page))
 599		return 1;
 600	if (!page_is_consistent(zone, page))
 601		return 1;
 602
 603	return 0;
 604}
 605#else
 606static inline int __maybe_unused bad_range(struct zone *zone, struct page *page)
 607{
 608	return 0;
 609}
 610#endif
 611
 612static void bad_page(struct page *page, const char *reason,
 613		unsigned long bad_flags)
 614{
 615	static unsigned long resume;
 616	static unsigned long nr_shown;
 617	static unsigned long nr_unshown;
 618
 619	/*
 620	 * Allow a burst of 60 reports, then keep quiet for that minute;
 621	 * or allow a steady drip of one report per second.
 622	 */
 623	if (nr_shown == 60) {
 624		if (time_before(jiffies, resume)) {
 625			nr_unshown++;
 626			goto out;
 627		}
 628		if (nr_unshown) {
 629			pr_alert(
 630			      "BUG: Bad page state: %lu messages suppressed\n",
 631				nr_unshown);
 632			nr_unshown = 0;
 633		}
 634		nr_shown = 0;
 635	}
 636	if (nr_shown++ == 0)
 637		resume = jiffies + 60 * HZ;
 638
 639	pr_alert("BUG: Bad page state in process %s  pfn:%05lx\n",
 640		current->comm, page_to_pfn(page));
 641	__dump_page(page, reason);
 642	bad_flags &= page->flags;
 643	if (bad_flags)
 644		pr_alert("bad because of flags: %#lx(%pGp)\n",
 645						bad_flags, &bad_flags);
 646	dump_page_owner(page);
 647
 648	print_modules();
 649	dump_stack();
 650out:
 651	/* Leave bad fields for debug, except PageBuddy could make trouble */
 652	page_mapcount_reset(page); /* remove PageBuddy */
 653	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 654}
 655
 656/*
 657 * Higher-order pages are called "compound pages".  They are structured thusly:
 658 *
 659 * The first PAGE_SIZE page is called the "head page" and have PG_head set.
 660 *
 661 * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded
 662 * in bit 0 of page->compound_head. The rest of bits is pointer to head page.
 663 *
 664 * The first tail page's ->compound_dtor holds the offset in array of compound
 665 * page destructors. See compound_page_dtors.
 666 *
 667 * The first tail page's ->compound_order holds the order of allocation.
 668 * This usage means that zero-order pages may not be compound.
 669 */
 670
 671void free_compound_page(struct page *page)
 672{
 673	mem_cgroup_uncharge(page);
 674	__free_pages_ok(page, compound_order(page));
 675}
 676
 677void prep_compound_page(struct page *page, unsigned int order)
 678{
 679	int i;
 680	int nr_pages = 1 << order;
 681
 682	set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
 683	set_compound_order(page, order);
 684	__SetPageHead(page);
 685	for (i = 1; i < nr_pages; i++) {
 686		struct page *p = page + i;
 687		set_page_count(p, 0);
 688		p->mapping = TAIL_MAPPING;
 689		set_compound_head(p, page);
 690	}
 691	atomic_set(compound_mapcount_ptr(page), -1);
 692}
 693
 694#ifdef CONFIG_DEBUG_PAGEALLOC
 695unsigned int _debug_guardpage_minorder;
 696
 697#ifdef CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT
 698DEFINE_STATIC_KEY_TRUE(_debug_pagealloc_enabled);
 699#else
 700DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
 701#endif
 702EXPORT_SYMBOL(_debug_pagealloc_enabled);
 703
 704DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
 
 705
 706static int __init early_debug_pagealloc(char *buf)
 707{
 708	bool enable = false;
 709
 710	if (kstrtobool(buf, &enable))
 711		return -EINVAL;
 712
 713	if (enable)
 714		static_branch_enable(&_debug_pagealloc_enabled);
 
 
 
 
 715
 716	return 0;
 717}
 718early_param("debug_pagealloc", early_debug_pagealloc);
 719
 720static void init_debug_guardpage(void)
 721{
 722	if (!debug_pagealloc_enabled())
 723		return;
 724
 725	if (!debug_guardpage_minorder())
 726		return;
 727
 728	static_branch_enable(&_debug_guardpage_enabled);
 729}
 730
 731static int __init debug_guardpage_minorder_setup(char *buf)
 732{
 733	unsigned long res;
 734
 735	if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
 736		pr_err("Bad debug_guardpage_minorder value\n");
 737		return 0;
 738	}
 739	_debug_guardpage_minorder = res;
 740	pr_info("Setting debug_guardpage_minorder to %lu\n", res);
 741	return 0;
 742}
 743early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
 744
 745static inline bool set_page_guard(struct zone *zone, struct page *page,
 746				unsigned int order, int migratetype)
 747{
 748	if (!debug_guardpage_enabled())
 749		return false;
 
 
 
 
 
 
 750
 751	if (order >= debug_guardpage_minorder())
 752		return false;
 
 
 753
 754	__SetPageGuard(page);
 755	INIT_LIST_HEAD(&page->lru);
 756	set_page_private(page, order);
 757	/* Guard pages are not available for any usage */
 758	__mod_zone_freepage_state(zone, -(1 << order), migratetype);
 759
 760	return true;
 761}
 762
 763static inline void clear_page_guard(struct zone *zone, struct page *page,
 764				unsigned int order, int migratetype)
 765{
 766	if (!debug_guardpage_enabled())
 
 767		return;
 
 768
 769	__ClearPageGuard(page);
 
 770
 771	set_page_private(page, 0);
 772	if (!is_migrate_isolate(migratetype))
 773		__mod_zone_freepage_state(zone, (1 << order), migratetype);
 774}
 775#else
 776static inline bool set_page_guard(struct zone *zone, struct page *page,
 777			unsigned int order, int migratetype) { return false; }
 778static inline void clear_page_guard(struct zone *zone, struct page *page,
 779				unsigned int order, int migratetype) {}
 780#endif
 781
 782static inline void set_page_order(struct page *page, unsigned int order)
 783{
 784	set_page_private(page, order);
 785	__SetPageBuddy(page);
 786}
 787
 788/*
 789 * This function checks whether a page is free && is the buddy
 790 * we can coalesce a page and its buddy if
 791 * (a) the buddy is not in a hole (check before calling!) &&
 792 * (b) the buddy is in the buddy system &&
 793 * (c) a page and its buddy have the same order &&
 794 * (d) a page and its buddy are in the same zone.
 795 *
 796 * For recording whether a page is in the buddy system, we set PageBuddy.
 797 * Setting, clearing, and testing PageBuddy is serialized by zone->lock.
 798 *
 799 * For recording page's order, we use page_private(page).
 800 */
 801static inline int page_is_buddy(struct page *page, struct page *buddy,
 802							unsigned int order)
 803{
 804	if (page_is_guard(buddy) && page_order(buddy) == order) {
 805		if (page_zone_id(page) != page_zone_id(buddy))
 806			return 0;
 807
 808		VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
 809
 810		return 1;
 811	}
 812
 813	if (PageBuddy(buddy) && page_order(buddy) == order) {
 814		/*
 815		 * zone check is done late to avoid uselessly
 816		 * calculating zone/node ids for pages that could
 817		 * never merge.
 818		 */
 819		if (page_zone_id(page) != page_zone_id(buddy))
 820			return 0;
 821
 822		VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
 823
 824		return 1;
 825	}
 826	return 0;
 827}
 828
 829#ifdef CONFIG_COMPACTION
 830static inline struct capture_control *task_capc(struct zone *zone)
 831{
 832	struct capture_control *capc = current->capture_control;
 833
 834	return capc &&
 835		!(current->flags & PF_KTHREAD) &&
 836		!capc->page &&
 837		capc->cc->zone == zone &&
 838		capc->cc->direct_compaction ? capc : NULL;
 839}
 840
 841static inline bool
 842compaction_capture(struct capture_control *capc, struct page *page,
 843		   int order, int migratetype)
 844{
 845	if (!capc || order != capc->cc->order)
 846		return false;
 847
 848	/* Do not accidentally pollute CMA or isolated regions*/
 849	if (is_migrate_cma(migratetype) ||
 850	    is_migrate_isolate(migratetype))
 851		return false;
 852
 853	/*
 854	 * Do not let lower order allocations polluate a movable pageblock.
 855	 * This might let an unmovable request use a reclaimable pageblock
 856	 * and vice-versa but no more than normal fallback logic which can
 857	 * have trouble finding a high-order free page.
 858	 */
 859	if (order < pageblock_order && migratetype == MIGRATE_MOVABLE)
 860		return false;
 861
 862	capc->page = page;
 863	return true;
 864}
 865
 866#else
 867static inline struct capture_control *task_capc(struct zone *zone)
 868{
 869	return NULL;
 870}
 871
 872static inline bool
 873compaction_capture(struct capture_control *capc, struct page *page,
 874		   int order, int migratetype)
 875{
 876	return false;
 877}
 878#endif /* CONFIG_COMPACTION */
 879
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 880/*
 881 * Freeing function for a buddy system allocator.
 882 *
 883 * The concept of a buddy system is to maintain direct-mapped table
 884 * (containing bit values) for memory blocks of various "orders".
 885 * The bottom level table contains the map for the smallest allocatable
 886 * units of memory (here, pages), and each level above it describes
 887 * pairs of units from the levels below, hence, "buddies".
 888 * At a high level, all that happens here is marking the table entry
 889 * at the bottom level available, and propagating the changes upward
 890 * as necessary, plus some accounting needed to play nicely with other
 891 * parts of the VM system.
 892 * At each level, we keep a list of pages, which are heads of continuous
 893 * free pages of length of (1 << order) and marked with PageBuddy.
 894 * Page's order is recorded in page_private(page) field.
 895 * So when we are allocating or freeing one, we can derive the state of the
 896 * other.  That is, if we allocate a small block, and both were
 897 * free, the remainder of the region must be split into blocks.
 898 * If a block is freed, and its buddy is also free, then this
 899 * triggers coalescing into a block of larger size.
 900 *
 901 * -- nyc
 902 */
 903
 904static inline void __free_one_page(struct page *page,
 905		unsigned long pfn,
 906		struct zone *zone, unsigned int order,
 907		int migratetype)
 908{
 
 
 909	unsigned long combined_pfn;
 910	unsigned long uninitialized_var(buddy_pfn);
 911	struct page *buddy;
 912	unsigned int max_order;
 913	struct capture_control *capc = task_capc(zone);
 914
 915	max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);
 916
 917	VM_BUG_ON(!zone_is_initialized(zone));
 918	VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
 919
 920	VM_BUG_ON(migratetype == -1);
 921	if (likely(!is_migrate_isolate(migratetype)))
 922		__mod_zone_freepage_state(zone, 1 << order, migratetype);
 923
 924	VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
 925	VM_BUG_ON_PAGE(bad_range(zone, page), page);
 926
 927continue_merging:
 928	while (order < max_order - 1) {
 929		if (compaction_capture(capc, page, order, migratetype)) {
 930			__mod_zone_freepage_state(zone, -(1 << order),
 931								migratetype);
 932			return;
 933		}
 934		buddy_pfn = __find_buddy_pfn(pfn, order);
 935		buddy = page + (buddy_pfn - pfn);
 936
 937		if (!pfn_valid_within(buddy_pfn))
 938			goto done_merging;
 939		if (!page_is_buddy(page, buddy, order))
 940			goto done_merging;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 941		/*
 942		 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
 943		 * merge with it and move up one order.
 944		 */
 945		if (page_is_guard(buddy))
 946			clear_page_guard(zone, buddy, order, migratetype);
 947		else
 948			del_page_from_free_area(buddy, &zone->free_area[order]);
 949		combined_pfn = buddy_pfn & pfn;
 950		page = page + (combined_pfn - pfn);
 951		pfn = combined_pfn;
 952		order++;
 953	}
 954	if (max_order < MAX_ORDER) {
 955		/* If we are here, it means order is >= pageblock_order.
 956		 * We want to prevent merge between freepages on isolate
 957		 * pageblock and normal pageblock. Without this, pageblock
 958		 * isolation could cause incorrect freepage or CMA accounting.
 959		 *
 960		 * We don't want to hit this code for the more frequent
 961		 * low-order merging.
 962		 */
 963		if (unlikely(has_isolate_pageblock(zone))) {
 964			int buddy_mt;
 965
 966			buddy_pfn = __find_buddy_pfn(pfn, order);
 967			buddy = page + (buddy_pfn - pfn);
 968			buddy_mt = get_pageblock_migratetype(buddy);
 969
 970			if (migratetype != buddy_mt
 971					&& (is_migrate_isolate(migratetype) ||
 972						is_migrate_isolate(buddy_mt)))
 973				goto done_merging;
 974		}
 975		max_order++;
 976		goto continue_merging;
 977	}
 978
 979done_merging:
 980	set_page_order(page, order);
 981
 982	/*
 983	 * If this is not the largest possible page, check if the buddy
 984	 * of the next-highest order is free. If it is, it's possible
 985	 * that pages are being freed that will coalesce soon. In case,
 986	 * that is happening, add the free page to the tail of the list
 987	 * so it's less likely to be used soon and more likely to be merged
 988	 * as a higher order page
 989	 */
 990	if ((order < MAX_ORDER-2) && pfn_valid_within(buddy_pfn)
 991			&& !is_shuffle_order(order)) {
 992		struct page *higher_page, *higher_buddy;
 993		combined_pfn = buddy_pfn & pfn;
 994		higher_page = page + (combined_pfn - pfn);
 995		buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1);
 996		higher_buddy = higher_page + (buddy_pfn - combined_pfn);
 997		if (pfn_valid_within(buddy_pfn) &&
 998		    page_is_buddy(higher_page, higher_buddy, order + 1)) {
 999			add_to_free_area_tail(page, &zone->free_area[order],
1000					      migratetype);
1001			return;
1002		}
1003	}
1004
1005	if (is_shuffle_order(order))
1006		add_to_free_area_random(page, &zone->free_area[order],
1007				migratetype);
1008	else
1009		add_to_free_area(page, &zone->free_area[order], migratetype);
1010
 
 
 
1011}
1012
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1013/*
1014 * A bad page could be due to a number of fields. Instead of multiple branches,
1015 * try and check multiple fields with one check. The caller must do a detailed
1016 * check if necessary.
1017 */
1018static inline bool page_expected_state(struct page *page,
1019					unsigned long check_flags)
1020{
1021	if (unlikely(atomic_read(&page->_mapcount) != -1))
1022		return false;
1023
1024	if (unlikely((unsigned long)page->mapping |
1025			page_ref_count(page) |
1026#ifdef CONFIG_MEMCG
1027			(unsigned long)page->mem_cgroup |
 
 
 
1028#endif
1029			(page->flags & check_flags)))
1030		return false;
1031
1032	return true;
1033}
1034
1035static void free_pages_check_bad(struct page *page)
1036{
1037	const char *bad_reason;
1038	unsigned long bad_flags;
1039
1040	bad_reason = NULL;
1041	bad_flags = 0;
1042
1043	if (unlikely(atomic_read(&page->_mapcount) != -1))
1044		bad_reason = "nonzero mapcount";
1045	if (unlikely(page->mapping != NULL))
1046		bad_reason = "non-NULL mapping";
1047	if (unlikely(page_ref_count(page) != 0))
1048		bad_reason = "nonzero _refcount";
1049	if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
1050		bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
1051		bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
 
 
1052	}
1053#ifdef CONFIG_MEMCG
1054	if (unlikely(page->mem_cgroup))
1055		bad_reason = "page still charged to cgroup";
1056#endif
1057	bad_page(page, bad_reason, bad_flags);
 
 
 
 
1058}
1059
1060static inline int free_pages_check(struct page *page)
 
 
 
 
 
 
1061{
1062	if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE)))
1063		return 0;
1064
1065	/* Something has gone sideways, find it */
1066	free_pages_check_bad(page);
1067	return 1;
1068}
1069
1070static int free_tail_pages_check(struct page *head_page, struct page *page)
1071{
 
 
 
 
 
 
1072	int ret = 1;
1073
1074	/*
1075	 * We rely page->lru.next never has bit 0 set, unless the page
1076	 * is PageTail(). Let's make sure that's true even for poisoned ->lru.
1077	 */
1078	BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1);
1079
1080	if (!IS_ENABLED(CONFIG_DEBUG_VM)) {
1081		ret = 0;
1082		goto out;
1083	}
1084	switch (page - head_page) {
1085	case 1:
1086		/* the first tail page: ->mapping may be compound_mapcount() */
1087		if (unlikely(compound_mapcount(page))) {
1088			bad_page(page, "nonzero compound_mapcount", 0);
 
 
 
 
 
 
 
 
1089			goto out;
1090		}
1091		break;
1092	case 2:
1093		/*
1094		 * the second tail page: ->mapping is
1095		 * deferred_list.next -- ignore value.
1096		 */
1097		break;
1098	default:
1099		if (page->mapping != TAIL_MAPPING) {
1100			bad_page(page, "corrupted mapping in tail page", 0);
1101			goto out;
1102		}
1103		break;
1104	}
1105	if (unlikely(!PageTail(page))) {
1106		bad_page(page, "PageTail not set", 0);
1107		goto out;
1108	}
1109	if (unlikely(compound_head(page) != head_page)) {
1110		bad_page(page, "compound_head not consistent", 0);
1111		goto out;
1112	}
1113	ret = 0;
1114out:
1115	page->mapping = NULL;
1116	clear_compound_head(page);
1117	return ret;
1118}
1119
1120static void kernel_init_free_pages(struct page *page, int numpages)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1121{
1122	int i;
1123
 
 
1124	for (i = 0; i < numpages; i++)
1125		clear_highpage(page + i);
 
1126}
1127
1128static __always_inline bool free_pages_prepare(struct page *page,
1129					unsigned int order, bool check_free)
1130{
1131	int bad = 0;
 
 
 
1132
1133	VM_BUG_ON_PAGE(PageTail(page), page);
1134
1135	trace_mm_page_free(page, order);
 
 
 
 
 
 
 
 
 
 
 
 
 
1136
1137	/*
1138	 * Check tail pages before head page information is cleared to
1139	 * avoid checking PageCompound for order-0 pages.
1140	 */
1141	if (unlikely(order)) {
1142		bool compound = PageCompound(page);
1143		int i;
1144
1145		VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
1146
1147		if (compound)
1148			ClearPageDoubleMap(page);
1149		for (i = 1; i < (1 << order); i++) {
1150			if (compound)
1151				bad += free_tail_pages_check(page, page + i);
1152			if (unlikely(free_pages_check(page + i))) {
1153				bad++;
1154				continue;
 
 
1155			}
1156			(page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1157		}
1158	}
1159	if (PageMappingFlags(page))
1160		page->mapping = NULL;
1161	if (memcg_kmem_enabled() && PageKmemcg(page))
1162		__memcg_kmem_uncharge(page, order);
1163	if (check_free)
1164		bad += free_pages_check(page);
1165	if (bad)
1166		return false;
1167
1168	page_cpupid_reset_last(page);
1169	page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1170	reset_page_owner(page, order);
 
1171
1172	if (!PageHighMem(page)) {
1173		debug_check_no_locks_freed(page_address(page),
1174					   PAGE_SIZE << order);
1175		debug_check_no_obj_freed(page_address(page),
1176					   PAGE_SIZE << order);
1177	}
1178	if (want_init_on_free())
1179		kernel_init_free_pages(page, 1 << order);
1180
1181	kernel_poison_pages(page, 1 << order, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1182	/*
1183	 * arch_free_page() can make the page's contents inaccessible.  s390
1184	 * does this.  So nothing which can access the page's contents should
1185	 * happen after this.
1186	 */
1187	arch_free_page(page, order);
1188
1189	if (debug_pagealloc_enabled())
1190		kernel_map_pages(page, 1 << order, 0);
1191
1192	kasan_free_nondeferred_pages(page, order);
1193
1194	return true;
1195}
1196
1197#ifdef CONFIG_DEBUG_VM
1198/*
1199 * With DEBUG_VM enabled, order-0 pages are checked immediately when being freed
1200 * to pcp lists. With debug_pagealloc also enabled, they are also rechecked when
1201 * moved from pcp lists to free lists.
1202 */
1203static bool free_pcp_prepare(struct page *page)
1204{
1205	return free_pages_prepare(page, 0, true);
1206}
1207
1208static bool bulkfree_pcp_prepare(struct page *page)
1209{
1210	if (debug_pagealloc_enabled())
1211		return free_pages_check(page);
1212	else
1213		return false;
1214}
1215#else
1216/*
1217 * With DEBUG_VM disabled, order-0 pages being freed are checked only when
1218 * moving from pcp lists to free list in order to reduce overhead. With
1219 * debug_pagealloc enabled, they are checked also immediately when being freed
1220 * to the pcp lists.
1221 */
1222static bool free_pcp_prepare(struct page *page)
1223{
1224	if (debug_pagealloc_enabled())
1225		return free_pages_prepare(page, 0, true);
1226	else
1227		return free_pages_prepare(page, 0, false);
1228}
1229
1230static bool bulkfree_pcp_prepare(struct page *page)
1231{
1232	return free_pages_check(page);
1233}
1234#endif /* CONFIG_DEBUG_VM */
1235
1236static inline void prefetch_buddy(struct page *page)
1237{
1238	unsigned long pfn = page_to_pfn(page);
1239	unsigned long buddy_pfn = __find_buddy_pfn(pfn, 0);
1240	struct page *buddy = page + (buddy_pfn - pfn);
1241
1242	prefetch(buddy);
1243}
1244
1245/*
1246 * Frees a number of pages from the PCP lists
1247 * Assumes all pages on list are in same zone, and of same order.
1248 * count is the number of pages to free.
1249 *
1250 * If the zone was previously in an "all pages pinned" state then look to
1251 * see if this freeing clears that state.
1252 *
1253 * And clear the zone's pages_scanned counter, to hold off the "all pages are
1254 * pinned" detection logic.
1255 */
1256static void free_pcppages_bulk(struct zone *zone, int count,
1257					struct per_cpu_pages *pcp)
 
1258{
1259	int migratetype = 0;
1260	int batch_free = 0;
1261	int prefetch_nr = 0;
1262	bool isolated_pageblocks;
1263	struct page *page, *tmp;
1264	LIST_HEAD(head);
 
 
 
 
 
 
 
 
1265
1266	while (count) {
 
 
 
1267		struct list_head *list;
 
1268
1269		/*
1270		 * Remove pages from lists in a round-robin fashion. A
1271		 * batch_free count is maintained that is incremented when an
1272		 * empty list is encountered.  This is so more pages are freed
1273		 * off fuller lists instead of spinning excessively around empty
1274		 * lists
1275		 */
1276		do {
1277			batch_free++;
1278			if (++migratetype == MIGRATE_PCPTYPES)
1279				migratetype = 0;
1280			list = &pcp->lists[migratetype];
1281		} while (list_empty(list));
1282
1283		/* This is the only non-empty list. Free them all. */
1284		if (batch_free == MIGRATE_PCPTYPES)
1285			batch_free = count;
1286
1287		do {
1288			page = list_last_entry(list, struct page, lru);
1289			/* must delete to avoid corrupting pcp list */
1290			list_del(&page->lru);
1291			pcp->count--;
1292
1293			if (bulkfree_pcp_prepare(page))
1294				continue;
1295
1296			list_add_tail(&page->lru, &head);
 
1297
1298			/*
1299			 * We are going to put the page back to the global
1300			 * pool, prefetch its buddy to speed up later access
1301			 * under zone->lock. It is believed the overhead of
1302			 * an additional test and calculating buddy_pfn here
1303			 * can be offset by reduced memory latency later. To
1304			 * avoid excessive prefetching due to large count, only
1305			 * prefetch buddy for the first pcp->batch nr of pages.
1306			 */
1307			if (prefetch_nr++ < pcp->batch)
1308				prefetch_buddy(page);
1309		} while (--count && --batch_free && !list_empty(list));
 
 
1310	}
1311
1312	spin_lock(&zone->lock);
1313	isolated_pageblocks = has_isolate_pageblock(zone);
1314
1315	/*
1316	 * Use safe version since after __free_one_page(),
1317	 * page->lru.next will not point to original list.
1318	 */
1319	list_for_each_entry_safe(page, tmp, &head, lru) {
1320		int mt = get_pcppage_migratetype(page);
1321		/* MIGRATE_ISOLATE page should not go to pcplists */
1322		VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
1323		/* Pageblock could have been isolated meanwhile */
1324		if (unlikely(isolated_pageblocks))
1325			mt = get_pageblock_migratetype(page);
1326
1327		__free_one_page(page, page_to_pfn(page), zone, 0, mt);
1328		trace_mm_page_pcpu_drain(page, 0, mt);
1329	}
1330	spin_unlock(&zone->lock);
1331}
1332
1333static void free_one_page(struct zone *zone,
1334				struct page *page, unsigned long pfn,
1335				unsigned int order,
1336				int migratetype)
1337{
1338	spin_lock(&zone->lock);
 
 
1339	if (unlikely(has_isolate_pageblock(zone) ||
1340		is_migrate_isolate(migratetype))) {
1341		migratetype = get_pfnblock_migratetype(page, pfn);
1342	}
1343	__free_one_page(page, pfn, zone, order, migratetype);
1344	spin_unlock(&zone->lock);
1345}
1346
1347static void __meminit __init_single_page(struct page *page, unsigned long pfn,
1348				unsigned long zone, int nid)
1349{
1350	mm_zero_struct_page(page);
1351	set_page_links(page, zone, nid, pfn);
1352	init_page_count(page);
1353	page_mapcount_reset(page);
1354	page_cpupid_reset_last(page);
1355	page_kasan_tag_reset(page);
1356
1357	INIT_LIST_HEAD(&page->lru);
1358#ifdef WANT_PAGE_VIRTUAL
1359	/* The shift won't overflow because ZONE_NORMAL is below 4G. */
1360	if (!is_highmem_idx(zone))
1361		set_page_address(page, __va(pfn << PAGE_SHIFT));
1362#endif
1363}
1364
1365#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1366static void __meminit init_reserved_page(unsigned long pfn)
1367{
1368	pg_data_t *pgdat;
1369	int nid, zid;
1370
1371	if (!early_page_uninitialised(pfn))
1372		return;
1373
1374	nid = early_pfn_to_nid(pfn);
1375	pgdat = NODE_DATA(nid);
1376
1377	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1378		struct zone *zone = &pgdat->node_zones[zid];
1379
1380		if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
1381			break;
1382	}
1383	__init_single_page(pfn_to_page(pfn), pfn, zid, nid);
1384}
1385#else
1386static inline void init_reserved_page(unsigned long pfn)
1387{
1388}
1389#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1390
1391/*
1392 * Initialised pages do not have PageReserved set. This function is
1393 * called for each range allocated by the bootmem allocator and
1394 * marks the pages PageReserved. The remaining valid pages are later
1395 * sent to the buddy page allocator.
1396 */
1397void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
1398{
1399	unsigned long start_pfn = PFN_DOWN(start);
1400	unsigned long end_pfn = PFN_UP(end);
1401
1402	for (; start_pfn < end_pfn; start_pfn++) {
1403		if (pfn_valid(start_pfn)) {
1404			struct page *page = pfn_to_page(start_pfn);
1405
1406			init_reserved_page(start_pfn);
1407
1408			/* Avoid false-positive PageTail() */
1409			INIT_LIST_HEAD(&page->lru);
1410
1411			/*
1412			 * no need for atomic set_bit because the struct
1413			 * page is not visible yet so nobody should
1414			 * access it yet.
1415			 */
1416			__SetPageReserved(page);
1417		}
1418	}
1419}
1420
1421static void __free_pages_ok(struct page *page, unsigned int order)
 
1422{
1423	unsigned long flags;
1424	int migratetype;
1425	unsigned long pfn = page_to_pfn(page);
 
1426
1427	if (!free_pages_prepare(page, order, true))
1428		return;
1429
 
 
 
 
 
1430	migratetype = get_pfnblock_migratetype(page, pfn);
1431	local_irq_save(flags);
 
 
1432	__count_vm_events(PGFREE, 1 << order);
1433	free_one_page(page_zone(page), page, pfn, order, migratetype);
1434	local_irq_restore(flags);
1435}
1436
1437void __free_pages_core(struct page *page, unsigned int order)
1438{
1439	unsigned int nr_pages = 1 << order;
1440	struct page *p = page;
1441	unsigned int loop;
1442
 
 
 
 
 
1443	prefetchw(p);
1444	for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
1445		prefetchw(p + 1);
1446		__ClearPageReserved(p);
1447		set_page_count(p, 0);
1448	}
1449	__ClearPageReserved(p);
1450	set_page_count(p, 0);
1451
1452	atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
1453	set_page_refcounted(page);
1454	__free_pages(page, order);
1455}
1456
1457#if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \
1458	defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
1459
1460static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
1461
1462int __meminit early_pfn_to_nid(unsigned long pfn)
1463{
1464	static DEFINE_SPINLOCK(early_pfn_lock);
1465	int nid;
1466
1467	spin_lock(&early_pfn_lock);
1468	nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
1469	if (nid < 0)
1470		nid = first_online_node;
1471	spin_unlock(&early_pfn_lock);
1472
1473	return nid;
1474}
1475#endif
1476
1477#ifdef CONFIG_NODES_SPAN_OTHER_NODES
1478/* Only safe to use early in boot when initialisation is single-threaded */
1479static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
1480{
1481	int nid;
1482
1483	nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
1484	if (nid >= 0 && nid != node)
1485		return false;
1486	return true;
1487}
1488
1489#else
1490static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
1491{
1492	return true;
1493}
1494#endif
1495
 
 
1496
1497void __init memblock_free_pages(struct page *page, unsigned long pfn,
1498							unsigned int order)
1499{
1500	if (early_page_uninitialised(pfn))
1501		return;
1502	__free_pages_core(page, order);
1503}
1504
1505/*
1506 * Check that the whole (or subset of) a pageblock given by the interval of
1507 * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
1508 * with the migration of free compaction scanner. The scanners then need to
1509 * use only pfn_valid_within() check for arches that allow holes within
1510 * pageblocks.
1511 *
1512 * Return struct page pointer of start_pfn, or NULL if checks were not passed.
1513 *
1514 * It's possible on some configurations to have a setup like node0 node1 node0
1515 * i.e. it's possible that all pages within a zones range of pages do not
1516 * belong to a single zone. We assume that a border between node0 and node1
1517 * can occur within a single pageblock, but not a node0 node1 node0
1518 * interleaving within a single pageblock. It is therefore sufficient to check
1519 * the first and last page of a pageblock and avoid checking each individual
1520 * page in a pageblock.
 
 
 
 
 
 
 
 
 
1521 */
1522struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
1523				     unsigned long end_pfn, struct zone *zone)
1524{
1525	struct page *start_page;
1526	struct page *end_page;
1527
1528	/* end_pfn is one past the range we are checking */
1529	end_pfn--;
1530
1531	if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
1532		return NULL;
1533
1534	start_page = pfn_to_online_page(start_pfn);
1535	if (!start_page)
1536		return NULL;
1537
1538	if (page_zone(start_page) != zone)
1539		return NULL;
1540
1541	end_page = pfn_to_page(end_pfn);
1542
1543	/* This gives a shorter code than deriving page_zone(end_page) */
1544	if (page_zone_id(start_page) != page_zone_id(end_page))
1545		return NULL;
1546
1547	return start_page;
1548}
1549
1550void set_zone_contiguous(struct zone *zone)
1551{
1552	unsigned long block_start_pfn = zone->zone_start_pfn;
1553	unsigned long block_end_pfn;
1554
1555	block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages);
1556	for (; block_start_pfn < zone_end_pfn(zone);
1557			block_start_pfn = block_end_pfn,
1558			 block_end_pfn += pageblock_nr_pages) {
1559
1560		block_end_pfn = min(block_end_pfn, zone_end_pfn(zone));
1561
1562		if (!__pageblock_pfn_to_page(block_start_pfn,
1563					     block_end_pfn, zone))
1564			return;
1565	}
1566
1567	/* We confirm that there is no hole */
1568	zone->contiguous = true;
1569}
1570
1571void clear_zone_contiguous(struct zone *zone)
1572{
1573	zone->contiguous = false;
1574}
1575
1576#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1577static void __init deferred_free_range(unsigned long pfn,
1578				       unsigned long nr_pages)
1579{
1580	struct page *page;
1581	unsigned long i;
1582
1583	if (!nr_pages)
1584		return;
1585
1586	page = pfn_to_page(pfn);
1587
1588	/* Free a large naturally-aligned chunk if possible */
1589	if (nr_pages == pageblock_nr_pages &&
1590	    (pfn & (pageblock_nr_pages - 1)) == 0) {
1591		set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1592		__free_pages_core(page, pageblock_order);
1593		return;
1594	}
1595
1596	for (i = 0; i < nr_pages; i++, page++, pfn++) {
1597		if ((pfn & (pageblock_nr_pages - 1)) == 0)
1598			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1599		__free_pages_core(page, 0);
1600	}
1601}
1602
1603/* Completion tracking for deferred_init_memmap() threads */
1604static atomic_t pgdat_init_n_undone __initdata;
1605static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp);
1606
1607static inline void __init pgdat_init_report_one_done(void)
1608{
1609	if (atomic_dec_and_test(&pgdat_init_n_undone))
1610		complete(&pgdat_init_all_done_comp);
1611}
1612
1613/*
1614 * Returns true if page needs to be initialized or freed to buddy allocator.
1615 *
1616 * First we check if pfn is valid on architectures where it is possible to have
1617 * holes within pageblock_nr_pages. On systems where it is not possible, this
1618 * function is optimized out.
1619 *
1620 * Then, we check if a current large page is valid by only checking the validity
1621 * of the head pfn.
1622 */
1623static inline bool __init deferred_pfn_valid(unsigned long pfn)
1624{
1625	if (!pfn_valid_within(pfn))
1626		return false;
1627	if (!(pfn & (pageblock_nr_pages - 1)) && !pfn_valid(pfn))
1628		return false;
1629	return true;
1630}
1631
1632/*
1633 * Free pages to buddy allocator. Try to free aligned pages in
1634 * pageblock_nr_pages sizes.
1635 */
1636static void __init deferred_free_pages(unsigned long pfn,
1637				       unsigned long end_pfn)
1638{
1639	unsigned long nr_pgmask = pageblock_nr_pages - 1;
1640	unsigned long nr_free = 0;
1641
1642	for (; pfn < end_pfn; pfn++) {
1643		if (!deferred_pfn_valid(pfn)) {
1644			deferred_free_range(pfn - nr_free, nr_free);
1645			nr_free = 0;
1646		} else if (!(pfn & nr_pgmask)) {
1647			deferred_free_range(pfn - nr_free, nr_free);
1648			nr_free = 1;
1649			touch_nmi_watchdog();
1650		} else {
1651			nr_free++;
1652		}
1653	}
1654	/* Free the last block of pages to allocator */
1655	deferred_free_range(pfn - nr_free, nr_free);
1656}
1657
1658/*
1659 * Initialize struct pages.  We minimize pfn page lookups and scheduler checks
1660 * by performing it only once every pageblock_nr_pages.
1661 * Return number of pages initialized.
1662 */
1663static unsigned long  __init deferred_init_pages(struct zone *zone,
1664						 unsigned long pfn,
1665						 unsigned long end_pfn)
1666{
1667	unsigned long nr_pgmask = pageblock_nr_pages - 1;
1668	int nid = zone_to_nid(zone);
1669	unsigned long nr_pages = 0;
1670	int zid = zone_idx(zone);
1671	struct page *page = NULL;
1672
1673	for (; pfn < end_pfn; pfn++) {
1674		if (!deferred_pfn_valid(pfn)) {
1675			page = NULL;
1676			continue;
1677		} else if (!page || !(pfn & nr_pgmask)) {
1678			page = pfn_to_page(pfn);
1679			touch_nmi_watchdog();
1680		} else {
1681			page++;
1682		}
1683		__init_single_page(page, pfn, zid, nid);
1684		nr_pages++;
1685	}
1686	return (nr_pages);
1687}
1688
1689/*
1690 * This function is meant to pre-load the iterator for the zone init.
1691 * Specifically it walks through the ranges until we are caught up to the
1692 * first_init_pfn value and exits there. If we never encounter the value we
1693 * return false indicating there are no valid ranges left.
1694 */
1695static bool __init
1696deferred_init_mem_pfn_range_in_zone(u64 *i, struct zone *zone,
1697				    unsigned long *spfn, unsigned long *epfn,
1698				    unsigned long first_init_pfn)
1699{
1700	u64 j;
1701
1702	/*
1703	 * Start out by walking through the ranges in this zone that have
1704	 * already been initialized. We don't need to do anything with them
1705	 * so we just need to flush them out of the system.
1706	 */
1707	for_each_free_mem_pfn_range_in_zone(j, zone, spfn, epfn) {
1708		if (*epfn <= first_init_pfn)
1709			continue;
1710		if (*spfn < first_init_pfn)
1711			*spfn = first_init_pfn;
1712		*i = j;
1713		return true;
1714	}
1715
1716	return false;
1717}
1718
1719/*
1720 * Initialize and free pages. We do it in two loops: first we initialize
1721 * struct page, then free to buddy allocator, because while we are
1722 * freeing pages we can access pages that are ahead (computing buddy
1723 * page in __free_one_page()).
1724 *
1725 * In order to try and keep some memory in the cache we have the loop
1726 * broken along max page order boundaries. This way we will not cause
1727 * any issues with the buddy page computation.
1728 */
1729static unsigned long __init
1730deferred_init_maxorder(u64 *i, struct zone *zone, unsigned long *start_pfn,
1731		       unsigned long *end_pfn)
1732{
1733	unsigned long mo_pfn = ALIGN(*start_pfn + 1, MAX_ORDER_NR_PAGES);
1734	unsigned long spfn = *start_pfn, epfn = *end_pfn;
1735	unsigned long nr_pages = 0;
1736	u64 j = *i;
1737
1738	/* First we loop through and initialize the page values */
1739	for_each_free_mem_pfn_range_in_zone_from(j, zone, start_pfn, end_pfn) {
1740		unsigned long t;
1741
1742		if (mo_pfn <= *start_pfn)
1743			break;
1744
1745		t = min(mo_pfn, *end_pfn);
1746		nr_pages += deferred_init_pages(zone, *start_pfn, t);
1747
1748		if (mo_pfn < *end_pfn) {
1749			*start_pfn = mo_pfn;
1750			break;
1751		}
1752	}
1753
1754	/* Reset values and now loop through freeing pages as needed */
1755	swap(j, *i);
1756
1757	for_each_free_mem_pfn_range_in_zone_from(j, zone, &spfn, &epfn) {
1758		unsigned long t;
1759
1760		if (mo_pfn <= spfn)
1761			break;
1762
1763		t = min(mo_pfn, epfn);
1764		deferred_free_pages(spfn, t);
1765
1766		if (mo_pfn <= epfn)
1767			break;
1768	}
1769
1770	return nr_pages;
1771}
1772
1773/* Initialise remaining memory on a node */
1774static int __init deferred_init_memmap(void *data)
1775{
1776	pg_data_t *pgdat = data;
1777	const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
1778	unsigned long spfn = 0, epfn = 0, nr_pages = 0;
1779	unsigned long first_init_pfn, flags;
1780	unsigned long start = jiffies;
1781	struct zone *zone;
1782	int zid;
1783	u64 i;
1784
1785	/* Bind memory initialisation thread to a local node if possible */
1786	if (!cpumask_empty(cpumask))
1787		set_cpus_allowed_ptr(current, cpumask);
1788
1789	pgdat_resize_lock(pgdat, &flags);
1790	first_init_pfn = pgdat->first_deferred_pfn;
1791	if (first_init_pfn == ULONG_MAX) {
1792		pgdat_resize_unlock(pgdat, &flags);
1793		pgdat_init_report_one_done();
1794		return 0;
1795	}
1796
1797	/* Sanity check boundaries */
1798	BUG_ON(pgdat->first_deferred_pfn < pgdat->node_start_pfn);
1799	BUG_ON(pgdat->first_deferred_pfn > pgdat_end_pfn(pgdat));
1800	pgdat->first_deferred_pfn = ULONG_MAX;
1801
1802	/* Only the highest zone is deferred so find it */
1803	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1804		zone = pgdat->node_zones + zid;
1805		if (first_init_pfn < zone_end_pfn(zone))
1806			break;
1807	}
1808
1809	/* If the zone is empty somebody else may have cleared out the zone */
1810	if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
1811						 first_init_pfn))
1812		goto zone_empty;
1813
1814	/*
1815	 * Initialize and free pages in MAX_ORDER sized increments so
1816	 * that we can avoid introducing any issues with the buddy
1817	 * allocator.
1818	 */
1819	while (spfn < epfn)
1820		nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
1821zone_empty:
1822	pgdat_resize_unlock(pgdat, &flags);
1823
1824	/* Sanity check that the next zone really is unpopulated */
1825	WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));
1826
1827	pr_info("node %d initialised, %lu pages in %ums\n",
1828		pgdat->node_id,	nr_pages, jiffies_to_msecs(jiffies - start));
1829
1830	pgdat_init_report_one_done();
1831	return 0;
1832}
1833
1834/*
1835 * If this zone has deferred pages, try to grow it by initializing enough
1836 * deferred pages to satisfy the allocation specified by order, rounded up to
1837 * the nearest PAGES_PER_SECTION boundary.  So we're adding memory in increments
1838 * of SECTION_SIZE bytes by initializing struct pages in increments of
1839 * PAGES_PER_SECTION * sizeof(struct page) bytes.
1840 *
1841 * Return true when zone was grown, otherwise return false. We return true even
1842 * when we grow less than requested, to let the caller decide if there are
1843 * enough pages to satisfy the allocation.
1844 *
1845 * Note: We use noinline because this function is needed only during boot, and
1846 * it is called from a __ref function _deferred_grow_zone. This way we are
1847 * making sure that it is not inlined into permanent text section.
1848 */
1849static noinline bool __init
1850deferred_grow_zone(struct zone *zone, unsigned int order)
1851{
1852	unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION);
1853	pg_data_t *pgdat = zone->zone_pgdat;
1854	unsigned long first_deferred_pfn = pgdat->first_deferred_pfn;
1855	unsigned long spfn, epfn, flags;
1856	unsigned long nr_pages = 0;
1857	u64 i;
1858
1859	/* Only the last zone may have deferred pages */
1860	if (zone_end_pfn(zone) != pgdat_end_pfn(pgdat))
1861		return false;
1862
1863	pgdat_resize_lock(pgdat, &flags);
1864
1865	/*
1866	 * If deferred pages have been initialized while we were waiting for
1867	 * the lock, return true, as the zone was grown.  The caller will retry
1868	 * this zone.  We won't return to this function since the caller also
1869	 * has this static branch.
1870	 */
1871	if (!static_branch_unlikely(&deferred_pages)) {
1872		pgdat_resize_unlock(pgdat, &flags);
1873		return true;
1874	}
1875
1876	/*
1877	 * If someone grew this zone while we were waiting for spinlock, return
1878	 * true, as there might be enough pages already.
1879	 */
1880	if (first_deferred_pfn != pgdat->first_deferred_pfn) {
1881		pgdat_resize_unlock(pgdat, &flags);
1882		return true;
1883	}
1884
1885	/* If the zone is empty somebody else may have cleared out the zone */
1886	if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
1887						 first_deferred_pfn)) {
1888		pgdat->first_deferred_pfn = ULONG_MAX;
1889		pgdat_resize_unlock(pgdat, &flags);
1890		/* Retry only once. */
1891		return first_deferred_pfn != ULONG_MAX;
1892	}
1893
1894	/*
1895	 * Initialize and free pages in MAX_ORDER sized increments so
1896	 * that we can avoid introducing any issues with the buddy
1897	 * allocator.
1898	 */
1899	while (spfn < epfn) {
1900		/* update our first deferred PFN for this section */
1901		first_deferred_pfn = spfn;
1902
1903		nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
1904
1905		/* We should only stop along section boundaries */
1906		if ((first_deferred_pfn ^ spfn) < PAGES_PER_SECTION)
1907			continue;
1908
1909		/* If our quota has been met we can stop here */
1910		if (nr_pages >= nr_pages_needed)
1911			break;
1912	}
1913
1914	pgdat->first_deferred_pfn = spfn;
1915	pgdat_resize_unlock(pgdat, &flags);
1916
1917	return nr_pages > 0;
1918}
1919
1920/*
1921 * deferred_grow_zone() is __init, but it is called from
1922 * get_page_from_freelist() during early boot until deferred_pages permanently
1923 * disables this call. This is why we have refdata wrapper to avoid warning,
1924 * and to ensure that the function body gets unloaded.
1925 */
1926static bool __ref
1927_deferred_grow_zone(struct zone *zone, unsigned int order)
1928{
1929	return deferred_grow_zone(zone, order);
1930}
1931
1932#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1933
1934void __init page_alloc_init_late(void)
1935{
1936	struct zone *zone;
1937	int nid;
1938
1939#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1940
1941	/* There will be num_node_state(N_MEMORY) threads */
1942	atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY));
1943	for_each_node_state(nid, N_MEMORY) {
1944		kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid);
1945	}
1946
1947	/* Block until all are initialised */
1948	wait_for_completion(&pgdat_init_all_done_comp);
1949
1950	/*
1951	 * The number of managed pages has changed due to the initialisation
1952	 * so the pcpu batch and high limits needs to be updated or the limits
1953	 * will be artificially small.
1954	 */
1955	for_each_populated_zone(zone)
1956		zone_pcp_update(zone);
1957
1958	/*
1959	 * We initialized the rest of the deferred pages.  Permanently disable
1960	 * on-demand struct page initialization.
1961	 */
1962	static_branch_disable(&deferred_pages);
1963
1964	/* Reinit limits that are based on free pages after the kernel is up */
1965	files_maxfiles_init();
1966#endif
1967
1968	/* Discard memblock private memory */
1969	memblock_discard();
1970
1971	for_each_node_state(nid, N_MEMORY)
1972		shuffle_free_memory(NODE_DATA(nid));
1973
1974	for_each_populated_zone(zone)
1975		set_zone_contiguous(zone);
1976
1977#ifdef CONFIG_DEBUG_PAGEALLOC
1978	init_debug_guardpage();
1979#endif
1980}
1981
1982#ifdef CONFIG_CMA
1983/* Free whole pageblock and set its migration type to MIGRATE_CMA. */
1984void __init init_cma_reserved_pageblock(struct page *page)
1985{
1986	unsigned i = pageblock_nr_pages;
1987	struct page *p = page;
1988
1989	do {
1990		__ClearPageReserved(p);
1991		set_page_count(p, 0);
1992	} while (++p, --i);
1993
1994	set_pageblock_migratetype(page, MIGRATE_CMA);
1995
1996	if (pageblock_order >= MAX_ORDER) {
1997		i = pageblock_nr_pages;
1998		p = page;
1999		do {
2000			set_page_refcounted(p);
2001			__free_pages(p, MAX_ORDER - 1);
2002			p += MAX_ORDER_NR_PAGES;
2003		} while (i -= MAX_ORDER_NR_PAGES);
2004	} else {
2005		set_page_refcounted(page);
2006		__free_pages(page, pageblock_order);
2007	}
2008
2009	adjust_managed_page_count(page, pageblock_nr_pages);
2010}
2011#endif
2012
2013/*
2014 * The order of subdivision here is critical for the IO subsystem.
2015 * Please do not alter this order without good reasons and regression
2016 * testing. Specifically, as large blocks of memory are subdivided,
2017 * the order in which smaller blocks are delivered depends on the order
2018 * they're subdivided in this function. This is the primary factor
2019 * influencing the order in which pages are delivered to the IO
2020 * subsystem according to empirical testing, and this is also justified
2021 * by considering the behavior of a buddy system containing a single
2022 * large block of memory acted on by a series of small allocations.
2023 * This behavior is a critical factor in sglist merging's success.
2024 *
2025 * -- nyc
2026 */
2027static inline void expand(struct zone *zone, struct page *page,
2028	int low, int high, struct free_area *area,
2029	int migratetype)
2030{
2031	unsigned long size = 1 << high;
2032
2033	while (high > low) {
2034		area--;
2035		high--;
2036		size >>= 1;
2037		VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
2038
2039		/*
2040		 * Mark as guard pages (or page), that will allow to
2041		 * merge back to allocator when buddy will be freed.
2042		 * Corresponding page table entries will not be touched,
2043		 * pages will stay not present in virtual address space
2044		 */
2045		if (set_page_guard(zone, &page[size], high, migratetype))
2046			continue;
2047
2048		add_to_free_area(&page[size], area, migratetype);
2049		set_page_order(&page[size], high);
2050	}
2051}
2052
2053static void check_new_page_bad(struct page *page)
2054{
2055	const char *bad_reason = NULL;
2056	unsigned long bad_flags = 0;
2057
2058	if (unlikely(atomic_read(&page->_mapcount) != -1))
2059		bad_reason = "nonzero mapcount";
2060	if (unlikely(page->mapping != NULL))
2061		bad_reason = "non-NULL mapping";
2062	if (unlikely(page_ref_count(page) != 0))
2063		bad_reason = "nonzero _refcount";
2064	if (unlikely(page->flags & __PG_HWPOISON)) {
2065		bad_reason = "HWPoisoned (hardware-corrupted)";
2066		bad_flags = __PG_HWPOISON;
2067		/* Don't complain about hwpoisoned pages */
2068		page_mapcount_reset(page); /* remove PageBuddy */
2069		return;
2070	}
2071	if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
2072		bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
2073		bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
2074	}
2075#ifdef CONFIG_MEMCG
2076	if (unlikely(page->mem_cgroup))
2077		bad_reason = "page still charged to cgroup";
2078#endif
2079	bad_page(page, bad_reason, bad_flags);
2080}
2081
2082/*
2083 * This page is about to be returned from the page allocator
2084 */
2085static inline int check_new_page(struct page *page)
2086{
2087	if (likely(page_expected_state(page,
2088				PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON)))
2089		return 0;
2090
2091	check_new_page_bad(page);
2092	return 1;
2093}
2094
2095static inline bool free_pages_prezeroed(void)
2096{
2097	return (IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) &&
2098		page_poisoning_enabled()) || want_init_on_free();
2099}
2100
2101#ifdef CONFIG_DEBUG_VM
2102/*
2103 * With DEBUG_VM enabled, order-0 pages are checked for expected state when
2104 * being allocated from pcp lists. With debug_pagealloc also enabled, they are
2105 * also checked when pcp lists are refilled from the free lists.
2106 */
2107static inline bool check_pcp_refill(struct page *page)
2108{
2109	if (debug_pagealloc_enabled())
2110		return check_new_page(page);
2111	else
2112		return false;
2113}
2114
2115static inline bool check_new_pcp(struct page *page)
2116{
2117	return check_new_page(page);
2118}
2119#else
2120/*
2121 * With DEBUG_VM disabled, free order-0 pages are checked for expected state
2122 * when pcp lists are being refilled from the free lists. With debug_pagealloc
2123 * enabled, they are also checked when being allocated from the pcp lists.
2124 */
2125static inline bool check_pcp_refill(struct page *page)
2126{
2127	return check_new_page(page);
2128}
2129static inline bool check_new_pcp(struct page *page)
 
2130{
2131	if (debug_pagealloc_enabled())
2132		return check_new_page(page);
2133	else
2134		return false;
 
 
 
 
 
 
 
 
 
 
2135}
2136#endif /* CONFIG_DEBUG_VM */
2137
2138static bool check_new_pages(struct page *page, unsigned int order)
2139{
2140	int i;
2141	for (i = 0; i < (1 << order); i++) {
2142		struct page *p = page + i;
2143
2144		if (unlikely(check_new_page(p)))
2145			return true;
2146	}
2147
2148	return false;
 
2149}
2150
2151inline void post_alloc_hook(struct page *page, unsigned int order,
2152				gfp_t gfp_flags)
2153{
 
 
 
 
 
2154	set_page_private(page, 0);
2155	set_page_refcounted(page);
2156
2157	arch_alloc_page(page, order);
2158	if (debug_pagealloc_enabled())
2159		kernel_map_pages(page, 1 << order, 1);
2160	kasan_alloc_pages(page, order);
2161	kernel_poison_pages(page, 1 << order, 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2162	set_page_owner(page, order, gfp_flags);
 
2163}
2164
2165static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
2166							unsigned int alloc_flags)
2167{
2168	post_alloc_hook(page, order, gfp_flags);
2169
2170	if (!free_pages_prezeroed() && want_init_on_alloc(gfp_flags))
2171		kernel_init_free_pages(page, 1 << order);
2172
2173	if (order && (gfp_flags & __GFP_COMP))
2174		prep_compound_page(page, order);
2175
2176	/*
2177	 * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
2178	 * allocate the page. The expectation is that the caller is taking
2179	 * steps that will free more memory. The caller should avoid the page
2180	 * being used for !PFMEMALLOC purposes.
2181	 */
2182	if (alloc_flags & ALLOC_NO_WATERMARKS)
2183		set_page_pfmemalloc(page);
2184	else
2185		clear_page_pfmemalloc(page);
2186}
2187
2188/*
2189 * Go through the free lists for the given migratetype and remove
2190 * the smallest available page from the freelists
2191 */
2192static __always_inline
2193struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
2194						int migratetype)
2195{
2196	unsigned int current_order;
2197	struct free_area *area;
2198	struct page *page;
2199
2200	/* Find a page of the appropriate size in the preferred list */
2201	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
2202		area = &(zone->free_area[current_order]);
2203		page = get_page_from_free_area(area, migratetype);
2204		if (!page)
2205			continue;
2206		del_page_from_free_area(page, area);
2207		expand(zone, page, order, current_order, area, migratetype);
2208		set_pcppage_migratetype(page, migratetype);
 
 
 
2209		return page;
2210	}
2211
2212	return NULL;
2213}
2214
2215
2216/*
2217 * This array describes the order lists are fallen back to when
2218 * the free lists for the desirable migrate type are depleted
 
 
2219 */
2220static int fallbacks[MIGRATE_TYPES][4] = {
2221	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_TYPES },
2222	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
2223	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_TYPES },
2224#ifdef CONFIG_CMA
2225	[MIGRATE_CMA]         = { MIGRATE_TYPES }, /* Never used */
2226#endif
2227#ifdef CONFIG_MEMORY_ISOLATION
2228	[MIGRATE_ISOLATE]     = { MIGRATE_TYPES }, /* Never used */
2229#endif
2230};
2231
2232#ifdef CONFIG_CMA
2233static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone,
2234					unsigned int order)
2235{
2236	return __rmqueue_smallest(zone, order, MIGRATE_CMA);
2237}
2238#else
2239static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
2240					unsigned int order) { return NULL; }
2241#endif
2242
2243/*
2244 * Move the free pages in a range to the free lists of the requested type.
2245 * Note that start_page and end_pages are not aligned on a pageblock
2246 * boundary. If alignment is required, use move_freepages_block()
2247 */
2248static int move_freepages(struct zone *zone,
2249			  struct page *start_page, struct page *end_page,
2250			  int migratetype, int *num_movable)
2251{
2252	struct page *page;
 
2253	unsigned int order;
2254	int pages_moved = 0;
2255
2256	for (page = start_page; page <= end_page;) {
2257		if (!pfn_valid_within(page_to_pfn(page))) {
2258			page++;
2259			continue;
2260		}
2261
2262		if (!PageBuddy(page)) {
2263			/*
2264			 * We assume that pages that could be isolated for
2265			 * migration are movable. But we don't actually try
2266			 * isolating, as that would be expensive.
2267			 */
2268			if (num_movable &&
2269					(PageLRU(page) || __PageMovable(page)))
2270				(*num_movable)++;
2271
2272			page++;
2273			continue;
2274		}
2275
2276		/* Make sure we are not inadvertently changing nodes */
2277		VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
2278		VM_BUG_ON_PAGE(page_zone(page) != zone, page);
2279
2280		order = page_order(page);
2281		move_to_free_area(page, &zone->free_area[order], migratetype);
2282		page += 1 << order;
2283		pages_moved += 1 << order;
2284	}
2285
2286	return pages_moved;
2287}
2288
2289int move_freepages_block(struct zone *zone, struct page *page,
2290				int migratetype, int *num_movable)
2291{
2292	unsigned long start_pfn, end_pfn;
2293	struct page *start_page, *end_page;
2294
2295	if (num_movable)
2296		*num_movable = 0;
2297
2298	start_pfn = page_to_pfn(page);
2299	start_pfn = start_pfn & ~(pageblock_nr_pages-1);
2300	start_page = pfn_to_page(start_pfn);
2301	end_page = start_page + pageblock_nr_pages - 1;
2302	end_pfn = start_pfn + pageblock_nr_pages - 1;
2303
2304	/* Do not cross zone boundaries */
2305	if (!zone_spans_pfn(zone, start_pfn))
2306		start_page = page;
2307	if (!zone_spans_pfn(zone, end_pfn))
2308		return 0;
2309
2310	return move_freepages(zone, start_page, end_page, migratetype,
2311								num_movable);
2312}
2313
2314static void change_pageblock_range(struct page *pageblock_page,
2315					int start_order, int migratetype)
2316{
2317	int nr_pageblocks = 1 << (start_order - pageblock_order);
2318
2319	while (nr_pageblocks--) {
2320		set_pageblock_migratetype(pageblock_page, migratetype);
2321		pageblock_page += pageblock_nr_pages;
2322	}
2323}
2324
2325/*
2326 * When we are falling back to another migratetype during allocation, try to
2327 * steal extra free pages from the same pageblocks to satisfy further
2328 * allocations, instead of polluting multiple pageblocks.
2329 *
2330 * If we are stealing a relatively large buddy page, it is likely there will
2331 * be more free pages in the pageblock, so try to steal them all. For
2332 * reclaimable and unmovable allocations, we steal regardless of page size,
2333 * as fragmentation caused by those allocations polluting movable pageblocks
2334 * is worse than movable allocations stealing from unmovable and reclaimable
2335 * pageblocks.
2336 */
2337static bool can_steal_fallback(unsigned int order, int start_mt)
2338{
2339	/*
2340	 * Leaving this order check is intended, although there is
2341	 * relaxed order check in next check. The reason is that
2342	 * we can actually steal whole pageblock if this condition met,
2343	 * but, below check doesn't guarantee it and that is just heuristic
2344	 * so could be changed anytime.
2345	 */
2346	if (order >= pageblock_order)
2347		return true;
2348
2349	if (order >= pageblock_order / 2 ||
2350		start_mt == MIGRATE_RECLAIMABLE ||
2351		start_mt == MIGRATE_UNMOVABLE ||
2352		page_group_by_mobility_disabled)
2353		return true;
2354
2355	return false;
2356}
2357
2358static inline void boost_watermark(struct zone *zone)
2359{
2360	unsigned long max_boost;
2361
2362	if (!watermark_boost_factor)
2363		return;
 
 
 
 
 
 
 
 
2364
2365	max_boost = mult_frac(zone->_watermark[WMARK_HIGH],
2366			watermark_boost_factor, 10000);
2367
2368	/*
2369	 * high watermark may be uninitialised if fragmentation occurs
2370	 * very early in boot so do not boost. We do not fall
2371	 * through and boost by pageblock_nr_pages as failing
2372	 * allocations that early means that reclaim is not going
2373	 * to help and it may even be impossible to reclaim the
2374	 * boosted watermark resulting in a hang.
2375	 */
2376	if (!max_boost)
2377		return;
2378
2379	max_boost = max(pageblock_nr_pages, max_boost);
2380
2381	zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages,
2382		max_boost);
 
 
2383}
2384
2385/*
2386 * This function implements actual steal behaviour. If order is large enough,
2387 * we can steal whole pageblock. If not, we first move freepages in this
2388 * pageblock to our migratetype and determine how many already-allocated pages
2389 * are there in the pageblock with a compatible migratetype. If at least half
2390 * of pages are free or compatible, we can change migratetype of the pageblock
2391 * itself, so pages freed in the future will be put on the correct free list.
2392 */
2393static void steal_suitable_fallback(struct zone *zone, struct page *page,
2394		unsigned int alloc_flags, int start_type, bool whole_block)
2395{
2396	unsigned int current_order = page_order(page);
2397	struct free_area *area;
2398	int free_pages, movable_pages, alike_pages;
2399	int old_block_type;
2400
2401	old_block_type = get_pageblock_migratetype(page);
2402
2403	/*
2404	 * This can happen due to races and we want to prevent broken
2405	 * highatomic accounting.
2406	 */
2407	if (is_migrate_highatomic(old_block_type))
2408		goto single_page;
2409
2410	/* Take ownership for orders >= pageblock_order */
2411	if (current_order >= pageblock_order) {
2412		change_pageblock_range(page, current_order, start_type);
2413		goto single_page;
2414	}
2415
2416	/*
2417	 * Boost watermarks to increase reclaim pressure to reduce the
2418	 * likelihood of future fallbacks. Wake kswapd now as the node
2419	 * may be balanced overall and kswapd will not wake naturally.
2420	 */
2421	boost_watermark(zone);
2422	if (alloc_flags & ALLOC_KSWAPD)
2423		set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
2424
2425	/* We are not allowed to try stealing from the whole block */
2426	if (!whole_block)
2427		goto single_page;
2428
2429	free_pages = move_freepages_block(zone, page, start_type,
2430						&movable_pages);
 
 
 
 
2431	/*
2432	 * Determine how many pages are compatible with our allocation.
2433	 * For movable allocation, it's the number of movable pages which
2434	 * we just obtained. For other types it's a bit more tricky.
2435	 */
2436	if (start_type == MIGRATE_MOVABLE) {
2437		alike_pages = movable_pages;
2438	} else {
2439		/*
2440		 * If we are falling back a RECLAIMABLE or UNMOVABLE allocation
2441		 * to MOVABLE pageblock, consider all non-movable pages as
2442		 * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or
2443		 * vice versa, be conservative since we can't distinguish the
2444		 * exact migratetype of non-movable pages.
2445		 */
2446		if (old_block_type == MIGRATE_MOVABLE)
2447			alike_pages = pageblock_nr_pages
2448						- (free_pages + movable_pages);
2449		else
2450			alike_pages = 0;
2451	}
2452
2453	/* moving whole block can fail due to zone boundary conditions */
2454	if (!free_pages)
2455		goto single_page;
2456
2457	/*
2458	 * If a sufficient number of pages in the block are either free or of
2459	 * comparable migratability as our allocation, claim the whole block.
2460	 */
2461	if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||
2462			page_group_by_mobility_disabled)
2463		set_pageblock_migratetype(page, start_type);
2464
2465	return;
2466
2467single_page:
2468	area = &zone->free_area[current_order];
2469	move_to_free_area(page, area, start_type);
2470}
2471
2472/*
2473 * Check whether there is a suitable fallback freepage with requested order.
2474 * If only_stealable is true, this function returns fallback_mt only if
2475 * we can steal other freepages all together. This would help to reduce
2476 * fragmentation due to mixed migratetype pages in one pageblock.
2477 */
2478int find_suitable_fallback(struct free_area *area, unsigned int order,
2479			int migratetype, bool only_stealable, bool *can_steal)
2480{
2481	int i;
2482	int fallback_mt;
2483
2484	if (area->nr_free == 0)
2485		return -1;
2486
2487	*can_steal = false;
2488	for (i = 0;; i++) {
2489		fallback_mt = fallbacks[migratetype][i];
2490		if (fallback_mt == MIGRATE_TYPES)
2491			break;
2492
2493		if (free_area_empty(area, fallback_mt))
2494			continue;
2495
2496		if (can_steal_fallback(order, migratetype))
2497			*can_steal = true;
2498
2499		if (!only_stealable)
2500			return fallback_mt;
2501
2502		if (*can_steal)
2503			return fallback_mt;
2504	}
2505
2506	return -1;
2507}
2508
2509/*
2510 * Reserve a pageblock for exclusive use of high-order atomic allocations if
2511 * there are no empty page blocks that contain a page with a suitable order
2512 */
2513static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
2514				unsigned int alloc_order)
2515{
2516	int mt;
2517	unsigned long max_managed, flags;
2518
2519	/*
2520	 * Limit the number reserved to 1 pageblock or roughly 1% of a zone.
 
 
2521	 * Check is race-prone but harmless.
2522	 */
2523	max_managed = (zone_managed_pages(zone) / 100) + pageblock_nr_pages;
 
 
2524	if (zone->nr_reserved_highatomic >= max_managed)
2525		return;
2526
2527	spin_lock_irqsave(&zone->lock, flags);
2528
2529	/* Recheck the nr_reserved_highatomic limit under the lock */
2530	if (zone->nr_reserved_highatomic >= max_managed)
2531		goto out_unlock;
2532
2533	/* Yoink! */
2534	mt = get_pageblock_migratetype(page);
2535	if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt)
2536	    && !is_migrate_cma(mt)) {
2537		zone->nr_reserved_highatomic += pageblock_nr_pages;
2538		set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
2539		move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL);
2540	}
2541
2542out_unlock:
2543	spin_unlock_irqrestore(&zone->lock, flags);
2544}
2545
2546/*
2547 * Used when an allocation is about to fail under memory pressure. This
2548 * potentially hurts the reliability of high-order allocations when under
2549 * intense memory pressure but failed atomic allocations should be easier
2550 * to recover from than an OOM.
2551 *
2552 * If @force is true, try to unreserve a pageblock even though highatomic
2553 * pageblock is exhausted.
2554 */
2555static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
2556						bool force)
2557{
2558	struct zonelist *zonelist = ac->zonelist;
2559	unsigned long flags;
2560	struct zoneref *z;
2561	struct zone *zone;
2562	struct page *page;
2563	int order;
2564	bool ret;
2565
2566	for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->high_zoneidx,
2567								ac->nodemask) {
2568		/*
2569		 * Preserve at least one pageblock unless memory pressure
2570		 * is really high.
2571		 */
2572		if (!force && zone->nr_reserved_highatomic <=
2573					pageblock_nr_pages)
2574			continue;
2575
2576		spin_lock_irqsave(&zone->lock, flags);
2577		for (order = 0; order < MAX_ORDER; order++) {
2578			struct free_area *area = &(zone->free_area[order]);
2579
2580			page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
2581			if (!page)
2582				continue;
2583
2584			/*
2585			 * In page freeing path, migratetype change is racy so
2586			 * we can counter several free pages in a pageblock
2587			 * in this loop althoug we changed the pageblock type
2588			 * from highatomic to ac->migratetype. So we should
2589			 * adjust the count once.
2590			 */
2591			if (is_migrate_highatomic_page(page)) {
2592				/*
2593				 * It should never happen but changes to
2594				 * locking could inadvertently allow a per-cpu
2595				 * drain to add pages to MIGRATE_HIGHATOMIC
2596				 * while unreserving so be safe and watch for
2597				 * underflows.
2598				 */
2599				zone->nr_reserved_highatomic -= min(
2600						pageblock_nr_pages,
2601						zone->nr_reserved_highatomic);
2602			}
2603
2604			/*
2605			 * Convert to ac->migratetype and avoid the normal
2606			 * pageblock stealing heuristics. Minimally, the caller
2607			 * is doing the work and needs the pages. More
2608			 * importantly, if the block was always converted to
2609			 * MIGRATE_UNMOVABLE or another type then the number
2610			 * of pageblocks that cannot be completely freed
2611			 * may increase.
2612			 */
2613			set_pageblock_migratetype(page, ac->migratetype);
2614			ret = move_freepages_block(zone, page, ac->migratetype,
2615									NULL);
2616			if (ret) {
2617				spin_unlock_irqrestore(&zone->lock, flags);
2618				return ret;
2619			}
2620		}
2621		spin_unlock_irqrestore(&zone->lock, flags);
2622	}
2623
2624	return false;
2625}
2626
2627/*
2628 * Try finding a free buddy page on the fallback list and put it on the free
2629 * list of requested migratetype, possibly along with other pages from the same
2630 * block, depending on fragmentation avoidance heuristics. Returns true if
2631 * fallback was found so that __rmqueue_smallest() can grab it.
2632 *
2633 * The use of signed ints for order and current_order is a deliberate
2634 * deviation from the rest of this file, to make the for loop
2635 * condition simpler.
2636 */
2637static __always_inline bool
2638__rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
2639						unsigned int alloc_flags)
2640{
2641	struct free_area *area;
2642	int current_order;
2643	int min_order = order;
2644	struct page *page;
2645	int fallback_mt;
2646	bool can_steal;
2647
2648	/*
2649	 * Do not steal pages from freelists belonging to other pageblocks
2650	 * i.e. orders < pageblock_order. If there are no local zones free,
2651	 * the zonelists will be reiterated without ALLOC_NOFRAGMENT.
2652	 */
2653	if (alloc_flags & ALLOC_NOFRAGMENT)
2654		min_order = pageblock_order;
2655
2656	/*
2657	 * Find the largest available free page in the other list. This roughly
2658	 * approximates finding the pageblock with the most free pages, which
2659	 * would be too costly to do exactly.
2660	 */
2661	for (current_order = MAX_ORDER - 1; current_order >= min_order;
2662				--current_order) {
2663		area = &(zone->free_area[current_order]);
2664		fallback_mt = find_suitable_fallback(area, current_order,
2665				start_migratetype, false, &can_steal);
2666		if (fallback_mt == -1)
2667			continue;
2668
2669		/*
2670		 * We cannot steal all free pages from the pageblock and the
2671		 * requested migratetype is movable. In that case it's better to
2672		 * steal and split the smallest available page instead of the
2673		 * largest available page, because even if the next movable
2674		 * allocation falls back into a different pageblock than this
2675		 * one, it won't cause permanent fragmentation.
2676		 */
2677		if (!can_steal && start_migratetype == MIGRATE_MOVABLE
2678					&& current_order > order)
2679			goto find_smallest;
2680
2681		goto do_steal;
2682	}
2683
2684	return false;
2685
2686find_smallest:
2687	for (current_order = order; current_order < MAX_ORDER;
2688							current_order++) {
2689		area = &(zone->free_area[current_order]);
2690		fallback_mt = find_suitable_fallback(area, current_order,
2691				start_migratetype, false, &can_steal);
2692		if (fallback_mt != -1)
2693			break;
2694	}
2695
2696	/*
2697	 * This should not happen - we already found a suitable fallback
2698	 * when looking for the largest page.
2699	 */
2700	VM_BUG_ON(current_order == MAX_ORDER);
2701
2702do_steal:
2703	page = get_page_from_free_area(area, fallback_mt);
2704
2705	steal_suitable_fallback(zone, page, alloc_flags, start_migratetype,
2706								can_steal);
2707
2708	trace_mm_page_alloc_extfrag(page, order, current_order,
2709		start_migratetype, fallback_mt);
2710
2711	return true;
2712
2713}
2714
2715/*
2716 * Do the hard work of removing an element from the buddy allocator.
2717 * Call me with the zone->lock already held.
2718 */
2719static __always_inline struct page *
2720__rmqueue(struct zone *zone, unsigned int order, int migratetype,
2721						unsigned int alloc_flags)
2722{
2723	struct page *page;
2724
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2725retry:
2726	page = __rmqueue_smallest(zone, order, migratetype);
2727	if (unlikely(!page)) {
2728		if (migratetype == MIGRATE_MOVABLE)
2729			page = __rmqueue_cma_fallback(zone, order);
2730
2731		if (!page && __rmqueue_fallback(zone, order, migratetype,
2732								alloc_flags))
2733			goto retry;
2734	}
2735
2736	trace_mm_page_alloc_zone_locked(page, order, migratetype);
2737	return page;
2738}
2739
2740/*
2741 * Obtain a specified number of elements from the buddy allocator, all under
2742 * a single hold of the lock, for efficiency.  Add them to the supplied list.
2743 * Returns the number of new pages which were placed at *list.
2744 */
2745static int rmqueue_bulk(struct zone *zone, unsigned int order,
2746			unsigned long count, struct list_head *list,
2747			int migratetype, unsigned int alloc_flags)
2748{
2749	int i, alloced = 0;
 
2750
2751	spin_lock(&zone->lock);
2752	for (i = 0; i < count; ++i) {
2753		struct page *page = __rmqueue(zone, order, migratetype,
2754								alloc_flags);
2755		if (unlikely(page == NULL))
2756			break;
2757
2758		if (unlikely(check_pcp_refill(page)))
2759			continue;
2760
2761		/*
2762		 * Split buddy pages returned by expand() are received here in
2763		 * physical page order. The page is added to the tail of
2764		 * caller's list. From the callers perspective, the linked list
2765		 * is ordered by page number under some conditions. This is
2766		 * useful for IO devices that can forward direction from the
2767		 * head, thus also in the physical page order. This is useful
2768		 * for IO devices that can merge IO requests if the physical
2769		 * pages are ordered properly.
2770		 */
2771		list_add_tail(&page->lru, list);
2772		alloced++;
2773		if (is_migrate_cma(get_pcppage_migratetype(page)))
2774			__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
2775					      -(1 << order));
2776	}
2777
2778	/*
2779	 * i pages were removed from the buddy list even if some leak due
2780	 * to check_pcp_refill failing so adjust NR_FREE_PAGES based
2781	 * on i. Do not confuse with 'alloced' which is the number of
2782	 * pages added to the pcp list.
2783	 */
2784	__mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
2785	spin_unlock(&zone->lock);
2786	return alloced;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2787}
2788
2789#ifdef CONFIG_NUMA
2790/*
2791 * Called from the vmstat counter updater to drain pagesets of this
2792 * currently executing processor on remote nodes after they have
2793 * expired.
2794 *
2795 * Note that this function must be called with the thread pinned to
2796 * a single processor.
2797 */
2798void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
2799{
2800	unsigned long flags;
2801	int to_drain, batch;
2802
2803	local_irq_save(flags);
2804	batch = READ_ONCE(pcp->batch);
2805	to_drain = min(pcp->count, batch);
2806	if (to_drain > 0)
2807		free_pcppages_bulk(zone, to_drain, pcp);
2808	local_irq_restore(flags);
 
 
2809}
2810#endif
2811
2812/*
2813 * Drain pcplists of the indicated processor and zone.
2814 *
2815 * The processor must either be the current processor and the
2816 * thread pinned to the current processor or a processor that
2817 * is not online.
2818 */
2819static void drain_pages_zone(unsigned int cpu, struct zone *zone)
2820{
2821	unsigned long flags;
2822	struct per_cpu_pageset *pset;
2823	struct per_cpu_pages *pcp;
2824
2825	local_irq_save(flags);
2826	pset = per_cpu_ptr(zone->pageset, cpu);
2827
2828	pcp = &pset->pcp;
2829	if (pcp->count)
2830		free_pcppages_bulk(zone, pcp->count, pcp);
2831	local_irq_restore(flags);
2832}
2833
2834/*
2835 * Drain pcplists of all zones on the indicated processor.
2836 *
2837 * The processor must either be the current processor and the
2838 * thread pinned to the current processor or a processor that
2839 * is not online.
2840 */
2841static void drain_pages(unsigned int cpu)
2842{
2843	struct zone *zone;
2844
2845	for_each_populated_zone(zone) {
2846		drain_pages_zone(cpu, zone);
2847	}
2848}
2849
2850/*
2851 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
2852 *
2853 * The CPU has to be pinned. When zone parameter is non-NULL, spill just
2854 * the single zone's pages.
2855 */
2856void drain_local_pages(struct zone *zone)
2857{
2858	int cpu = smp_processor_id();
2859
2860	if (zone)
2861		drain_pages_zone(cpu, zone);
2862	else
2863		drain_pages(cpu);
2864}
2865
2866static void drain_local_pages_wq(struct work_struct *work)
2867{
2868	struct pcpu_drain *drain;
2869
2870	drain = container_of(work, struct pcpu_drain, work);
2871
2872	/*
2873	 * drain_all_pages doesn't use proper cpu hotplug protection so
2874	 * we can race with cpu offline when the WQ can move this from
2875	 * a cpu pinned worker to an unbound one. We can operate on a different
2876	 * cpu which is allright but we also have to make sure to not move to
2877	 * a different one.
2878	 */
2879	preempt_disable();
2880	drain_local_pages(drain->zone);
2881	preempt_enable();
2882}
2883
2884/*
2885 * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
2886 *
2887 * When zone parameter is non-NULL, spill just the single zone's pages.
2888 *
2889 * Note that this can be extremely slow as the draining happens in a workqueue.
 
 
 
 
2890 */
2891void drain_all_pages(struct zone *zone)
2892{
2893	int cpu;
2894
2895	/*
2896	 * Allocate in the BSS so we wont require allocation in
2897	 * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
2898	 */
2899	static cpumask_t cpus_with_pcps;
2900
2901	/*
2902	 * Make sure nobody triggers this path before mm_percpu_wq is fully
2903	 * initialized.
2904	 */
2905	if (WARN_ON_ONCE(!mm_percpu_wq))
2906		return;
2907
2908	/*
2909	 * Do not drain if one is already in progress unless it's specific to
2910	 * a zone. Such callers are primarily CMA and memory hotplug and need
2911	 * the drain to be complete when the call returns.
2912	 */
2913	if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) {
2914		if (!zone)
2915			return;
2916		mutex_lock(&pcpu_drain_mutex);
2917	}
2918
2919	/*
2920	 * We don't care about racing with CPU hotplug event
2921	 * as offline notification will cause the notified
2922	 * cpu to drain that CPU pcps and on_each_cpu_mask
2923	 * disables preemption as part of its processing
2924	 */
2925	for_each_online_cpu(cpu) {
2926		struct per_cpu_pageset *pcp;
2927		struct zone *z;
2928		bool has_pcps = false;
2929
2930		if (zone) {
2931			pcp = per_cpu_ptr(zone->pageset, cpu);
2932			if (pcp->pcp.count)
 
 
 
 
 
 
2933				has_pcps = true;
2934		} else {
2935			for_each_populated_zone(z) {
2936				pcp = per_cpu_ptr(z->pageset, cpu);
2937				if (pcp->pcp.count) {
2938					has_pcps = true;
2939					break;
2940				}
2941			}
2942		}
2943
2944		if (has_pcps)
2945			cpumask_set_cpu(cpu, &cpus_with_pcps);
2946		else
2947			cpumask_clear_cpu(cpu, &cpus_with_pcps);
2948	}
2949
2950	for_each_cpu(cpu, &cpus_with_pcps) {
2951		struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu);
2952
2953		drain->zone = zone;
2954		INIT_WORK(&drain->work, drain_local_pages_wq);
2955		queue_work_on(cpu, mm_percpu_wq, &drain->work);
2956	}
2957	for_each_cpu(cpu, &cpus_with_pcps)
2958		flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work);
2959
2960	mutex_unlock(&pcpu_drain_mutex);
2961}
2962
2963#ifdef CONFIG_HIBERNATION
2964
2965/*
2966 * Touch the watchdog for every WD_PAGE_COUNT pages.
 
 
2967 */
2968#define WD_PAGE_COUNT	(128*1024)
2969
2970void mark_free_pages(struct zone *zone)
2971{
2972	unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
2973	unsigned long flags;
2974	unsigned int order, t;
2975	struct page *page;
2976
2977	if (zone_is_empty(zone))
2978		return;
2979
2980	spin_lock_irqsave(&zone->lock, flags);
2981
2982	max_zone_pfn = zone_end_pfn(zone);
2983	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
2984		if (pfn_valid(pfn)) {
2985			page = pfn_to_page(pfn);
2986
2987			if (!--page_count) {
2988				touch_nmi_watchdog();
2989				page_count = WD_PAGE_COUNT;
2990			}
2991
2992			if (page_zone(page) != zone)
2993				continue;
2994
2995			if (!swsusp_page_is_forbidden(page))
2996				swsusp_unset_page_free(page);
2997		}
2998
2999	for_each_migratetype_order(order, t) {
3000		list_for_each_entry(page,
3001				&zone->free_area[order].free_list[t], lru) {
3002			unsigned long i;
3003
3004			pfn = page_to_pfn(page);
3005			for (i = 0; i < (1UL << order); i++) {
3006				if (!--page_count) {
3007					touch_nmi_watchdog();
3008					page_count = WD_PAGE_COUNT;
3009				}
3010				swsusp_set_page_free(pfn_to_page(pfn + i));
3011			}
3012		}
3013	}
3014	spin_unlock_irqrestore(&zone->lock, flags);
3015}
3016#endif /* CONFIG_PM */
3017
3018static bool free_unref_page_prepare(struct page *page, unsigned long pfn)
 
3019{
3020	int migratetype;
3021
3022	if (!free_pcp_prepare(page))
3023		return false;
3024
3025	migratetype = get_pfnblock_migratetype(page, pfn);
3026	set_pcppage_migratetype(page, migratetype);
3027	return true;
3028}
3029
3030static void free_unref_page_commit(struct page *page, unsigned long pfn)
3031{
3032	struct zone *zone = page_zone(page);
3033	struct per_cpu_pages *pcp;
3034	int migratetype;
 
 
3035
3036	migratetype = get_pcppage_migratetype(page);
3037	__count_vm_event(PGFREE);
 
 
 
 
 
3038
3039	/*
3040	 * We only track unmovable, reclaimable and movable on pcp lists.
3041	 * Free ISOLATE pages back to the allocator because they are being
3042	 * offlined but treat HIGHATOMIC as movable pages so we can get those
3043	 * areas back if necessary. Otherwise, we may have to free
3044	 * excessively into the page allocator
3045	 */
3046	if (migratetype >= MIGRATE_PCPTYPES) {
3047		if (unlikely(is_migrate_isolate(migratetype))) {
3048			free_one_page(zone, page, pfn, 0, migratetype);
3049			return;
3050		}
3051		migratetype = MIGRATE_MOVABLE;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3052	}
3053
3054	pcp = &this_cpu_ptr(zone->pageset)->pcp;
3055	list_add(&page->lru, &pcp->lists[migratetype]);
3056	pcp->count++;
3057	if (pcp->count >= pcp->high) {
3058		unsigned long batch = READ_ONCE(pcp->batch);
3059		free_pcppages_bulk(zone, batch, pcp);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3060	}
3061}
3062
3063/*
3064 * Free a 0-order page
3065 */
3066void free_unref_page(struct page *page)
3067{
3068	unsigned long flags;
 
 
3069	unsigned long pfn = page_to_pfn(page);
 
3070
3071	if (!free_unref_page_prepare(page, pfn))
3072		return;
3073
3074	local_irq_save(flags);
3075	free_unref_page_commit(page, pfn);
3076	local_irq_restore(flags);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3077}
3078
3079/*
3080 * Free a list of 0-order pages
3081 */
3082void free_unref_page_list(struct list_head *list)
3083{
 
3084	struct page *page, *next;
3085	unsigned long flags, pfn;
 
3086	int batch_count = 0;
 
3087
3088	/* Prepare pages for freeing */
3089	list_for_each_entry_safe(page, next, list, lru) {
3090		pfn = page_to_pfn(page);
3091		if (!free_unref_page_prepare(page, pfn))
 
 
 
 
 
 
 
 
 
 
3092			list_del(&page->lru);
3093		set_page_private(page, pfn);
 
 
3094	}
3095
3096	local_irq_save(flags);
3097	list_for_each_entry_safe(page, next, list, lru) {
3098		unsigned long pfn = page_private(page);
3099
3100		set_page_private(page, 0);
3101		trace_mm_page_free_batched(page);
3102		free_unref_page_commit(page, pfn);
3103
3104		/*
3105		 * Guard against excessive IRQ disabled times when we get
3106		 * a large list of pages to free.
 
3107		 */
3108		if (++batch_count == SWAP_CLUSTER_MAX) {
3109			local_irq_restore(flags);
 
 
 
 
3110			batch_count = 0;
3111			local_irq_save(flags);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3112		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3113	}
3114	local_irq_restore(flags);
3115}
3116
3117/*
3118 * split_page takes a non-compound higher-order page, and splits it into
3119 * n (1<<order) sub-pages: page[0..n]
3120 * Each sub-page must be freed individually.
3121 *
3122 * Note: this is probably too low level an operation for use in drivers.
3123 * Please consult with lkml before using this in your driver.
3124 */
3125void split_page(struct page *page, unsigned int order)
3126{
3127	int i;
3128
3129	VM_BUG_ON_PAGE(PageCompound(page), page);
3130	VM_BUG_ON_PAGE(!page_count(page), page);
3131
3132	for (i = 1; i < (1 << order); i++)
3133		set_page_refcounted(page + i);
3134	split_page_owner(page, order);
 
3135}
3136EXPORT_SYMBOL_GPL(split_page);
3137
3138int __isolate_free_page(struct page *page, unsigned int order)
3139{
3140	struct free_area *area = &page_zone(page)->free_area[order];
3141	unsigned long watermark;
3142	struct zone *zone;
3143	int mt;
3144
3145	BUG_ON(!PageBuddy(page));
3146
3147	zone = page_zone(page);
3148	mt = get_pageblock_migratetype(page);
3149
3150	if (!is_migrate_isolate(mt)) {
 
3151		/*
3152		 * Obey watermarks as if the page was being allocated. We can
3153		 * emulate a high-order watermark check with a raised order-0
3154		 * watermark, because we already know our high-order page
3155		 * exists.
3156		 */
3157		watermark = zone->_watermark[WMARK_MIN] + (1UL << order);
3158		if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
3159			return 0;
3160
3161		__mod_zone_freepage_state(zone, -(1UL << order), mt);
3162	}
3163
3164	/* Remove page from free list */
3165
3166	del_page_from_free_area(page, area);
3167
3168	/*
3169	 * Set the pageblock if the isolated page is at least half of a
3170	 * pageblock
3171	 */
3172	if (order >= pageblock_order - 1) {
3173		struct page *endpage = page + (1 << order) - 1;
3174		for (; page < endpage; page += pageblock_nr_pages) {
3175			int mt = get_pageblock_migratetype(page);
3176			if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
3177			    && !is_migrate_highatomic(mt))
 
 
 
3178				set_pageblock_migratetype(page,
3179							  MIGRATE_MOVABLE);
3180		}
3181	}
3182
3183
3184	return 1UL << order;
3185}
3186
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3187/*
3188 * Update NUMA hit/miss statistics
3189 *
3190 * Must be called with interrupts disabled.
3191 */
3192static inline void zone_statistics(struct zone *preferred_zone, struct zone *z)
 
3193{
3194#ifdef CONFIG_NUMA
3195	enum numa_stat_item local_stat = NUMA_LOCAL;
3196
3197	/* skip numa counters update if numa stats is disabled */
3198	if (!static_branch_likely(&vm_numa_stat_key))
3199		return;
3200
3201	if (zone_to_nid(z) != numa_node_id())
3202		local_stat = NUMA_OTHER;
3203
3204	if (zone_to_nid(z) == zone_to_nid(preferred_zone))
3205		__inc_numa_state(z, NUMA_HIT);
3206	else {
3207		__inc_numa_state(z, NUMA_MISS);
3208		__inc_numa_state(preferred_zone, NUMA_FOREIGN);
3209	}
3210	__inc_numa_state(z, local_stat);
3211#endif
3212}
3213
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3214/* Remove page from the per-cpu list, caller must protect the list */
3215static struct page *__rmqueue_pcplist(struct zone *zone, int migratetype,
 
 
3216			unsigned int alloc_flags,
3217			struct per_cpu_pages *pcp,
3218			struct list_head *list)
3219{
3220	struct page *page;
3221
3222	do {
3223		if (list_empty(list)) {
3224			pcp->count += rmqueue_bulk(zone, 0,
3225					pcp->batch, list,
 
 
 
3226					migratetype, alloc_flags);
 
 
3227			if (unlikely(list_empty(list)))
3228				return NULL;
3229		}
3230
3231		page = list_first_entry(list, struct page, lru);
3232		list_del(&page->lru);
3233		pcp->count--;
3234	} while (check_new_pcp(page));
3235
3236	return page;
3237}
3238
3239/* Lock and remove page from the per-cpu list */
3240static struct page *rmqueue_pcplist(struct zone *preferred_zone,
3241			struct zone *zone, gfp_t gfp_flags,
3242			int migratetype, unsigned int alloc_flags)
3243{
3244	struct per_cpu_pages *pcp;
3245	struct list_head *list;
3246	struct page *page;
3247	unsigned long flags;
 
 
 
 
 
 
 
 
3248
3249	local_irq_save(flags);
3250	pcp = &this_cpu_ptr(zone->pageset)->pcp;
3251	list = &pcp->lists[migratetype];
3252	page = __rmqueue_pcplist(zone,  migratetype, alloc_flags, pcp, list);
 
 
 
 
 
 
3253	if (page) {
3254		__count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
3255		zone_statistics(preferred_zone, zone);
3256	}
3257	local_irq_restore(flags);
3258	return page;
3259}
3260
3261/*
3262 * Allocate a page from the given zone. Use pcplists for order-0 allocations.
 
 
 
 
 
 
 
 
3263 */
 
3264static inline
3265struct page *rmqueue(struct zone *preferred_zone,
3266			struct zone *zone, unsigned int order,
3267			gfp_t gfp_flags, unsigned int alloc_flags,
3268			int migratetype)
3269{
3270	unsigned long flags;
3271	struct page *page;
3272
3273	if (likely(order == 0)) {
3274		page = rmqueue_pcplist(preferred_zone, zone, gfp_flags,
3275					migratetype, alloc_flags);
3276		goto out;
3277	}
3278
3279	/*
3280	 * We most definitely don't want callers attempting to
3281	 * allocate greater than order-1 page units with __GFP_NOFAIL.
3282	 */
3283	WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
3284	spin_lock_irqsave(&zone->lock, flags);
3285
3286	do {
3287		page = NULL;
3288		if (alloc_flags & ALLOC_HARDER) {
3289			page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
3290			if (page)
3291				trace_mm_page_alloc_zone_locked(page, order, migratetype);
3292		}
3293		if (!page)
3294			page = __rmqueue(zone, order, migratetype, alloc_flags);
3295	} while (page && check_new_pages(page, order));
3296	spin_unlock(&zone->lock);
3297	if (!page)
3298		goto failed;
3299	__mod_zone_freepage_state(zone, -(1 << order),
3300				  get_pcppage_migratetype(page));
3301
3302	__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
3303	zone_statistics(preferred_zone, zone);
3304	local_irq_restore(flags);
3305
3306out:
3307	/* Separate test+clear to avoid unnecessary atomics */
3308	if (test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags)) {
 
3309		clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
3310		wakeup_kswapd(zone, 0, 0, zone_idx(zone));
3311	}
3312
3313	VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
3314	return page;
3315
3316failed:
3317	local_irq_restore(flags);
3318	return NULL;
3319}
3320
3321#ifdef CONFIG_FAIL_PAGE_ALLOC
3322
3323static struct {
3324	struct fault_attr attr;
3325
3326	bool ignore_gfp_highmem;
3327	bool ignore_gfp_reclaim;
3328	u32 min_order;
3329} fail_page_alloc = {
3330	.attr = FAULT_ATTR_INITIALIZER,
3331	.ignore_gfp_reclaim = true,
3332	.ignore_gfp_highmem = true,
3333	.min_order = 1,
3334};
3335
3336static int __init setup_fail_page_alloc(char *str)
3337{
3338	return setup_fault_attr(&fail_page_alloc.attr, str);
3339}
3340__setup("fail_page_alloc=", setup_fail_page_alloc);
3341
3342static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3343{
3344	if (order < fail_page_alloc.min_order)
3345		return false;
3346	if (gfp_mask & __GFP_NOFAIL)
3347		return false;
3348	if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
3349		return false;
3350	if (fail_page_alloc.ignore_gfp_reclaim &&
3351			(gfp_mask & __GFP_DIRECT_RECLAIM))
3352		return false;
3353
3354	return should_fail(&fail_page_alloc.attr, 1 << order);
3355}
 
3356
3357#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
3358
3359static int __init fail_page_alloc_debugfs(void)
3360{
3361	umode_t mode = S_IFREG | 0600;
3362	struct dentry *dir;
3363
3364	dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
3365					&fail_page_alloc.attr);
3366
3367	debugfs_create_bool("ignore-gfp-wait", mode, dir,
3368			    &fail_page_alloc.ignore_gfp_reclaim);
3369	debugfs_create_bool("ignore-gfp-highmem", mode, dir,
3370			    &fail_page_alloc.ignore_gfp_highmem);
3371	debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);
3372
3373	return 0;
3374}
3375
3376late_initcall(fail_page_alloc_debugfs);
3377
3378#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
3379
3380#else /* CONFIG_FAIL_PAGE_ALLOC */
3381
3382static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3383{
3384	return false;
3385}
3386
3387#endif /* CONFIG_FAIL_PAGE_ALLOC */
 
 
 
 
 
 
 
3388
3389static noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3390{
3391	return __should_fail_alloc_page(gfp_mask, order);
3392}
3393ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);
3394
3395/*
3396 * Return true if free base pages are above 'mark'. For high-order checks it
3397 * will return true of the order-0 watermark is reached and there is at least
3398 * one free page of a suitable size. Checking now avoids taking the zone lock
3399 * to check in the allocation paths if no pages are free.
3400 */
3401bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
3402			 int classzone_idx, unsigned int alloc_flags,
3403			 long free_pages)
3404{
3405	long min = mark;
3406	int o;
3407	const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM));
3408
3409	/* free_pages may go negative - that's OK */
3410	free_pages -= (1 << order) - 1;
3411
3412	if (alloc_flags & ALLOC_HIGH)
3413		min -= min / 2;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3414
3415	/*
3416	 * If the caller does not have rights to ALLOC_HARDER then subtract
3417	 * the high-atomic reserves. This will over-estimate the size of the
3418	 * atomic reserve but it avoids a search.
3419	 */
3420	if (likely(!alloc_harder)) {
3421		free_pages -= z->nr_reserved_highatomic;
3422	} else {
3423		/*
3424		 * OOM victims can try even harder than normal ALLOC_HARDER
3425		 * users on the grounds that it's definitely going to be in
3426		 * the exit path shortly and free memory. Any allocation it
3427		 * makes during the free path will be small and short-lived.
3428		 */
3429		if (alloc_flags & ALLOC_OOM)
3430			min -= min / 2;
3431		else
3432			min -= min / 4;
3433	}
3434
3435
3436#ifdef CONFIG_CMA
3437	/* If allocation can't use CMA areas don't use free CMA pages */
3438	if (!(alloc_flags & ALLOC_CMA))
3439		free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
3440#endif
3441
3442	/*
3443	 * Check watermarks for an order-0 allocation request. If these
3444	 * are not met, then a high-order request also cannot go ahead
3445	 * even if a suitable page happened to be free.
3446	 */
3447	if (free_pages <= min + z->lowmem_reserve[classzone_idx])
3448		return false;
3449
3450	/* If this is an order-0 request then the watermark is fine */
3451	if (!order)
3452		return true;
3453
3454	/* For a high-order request, check at least one suitable page is free */
3455	for (o = order; o < MAX_ORDER; o++) {
3456		struct free_area *area = &z->free_area[o];
3457		int mt;
3458
3459		if (!area->nr_free)
3460			continue;
3461
3462		for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
3463			if (!free_area_empty(area, mt))
3464				return true;
3465		}
3466
3467#ifdef CONFIG_CMA
3468		if ((alloc_flags & ALLOC_CMA) &&
3469		    !free_area_empty(area, MIGRATE_CMA)) {
3470			return true;
3471		}
3472#endif
3473		if (alloc_harder &&
3474			!list_empty(&area->free_list[MIGRATE_HIGHATOMIC]))
3475			return true;
 
3476	}
3477	return false;
3478}
3479
3480bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
3481		      int classzone_idx, unsigned int alloc_flags)
3482{
3483	return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
3484					zone_page_state(z, NR_FREE_PAGES));
3485}
3486
3487static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
3488		unsigned long mark, int classzone_idx, unsigned int alloc_flags)
 
3489{
3490	long free_pages = zone_page_state(z, NR_FREE_PAGES);
3491	long cma_pages = 0;
3492
3493#ifdef CONFIG_CMA
3494	/* If allocation can't use CMA areas don't use free CMA pages */
3495	if (!(alloc_flags & ALLOC_CMA))
3496		cma_pages = zone_page_state(z, NR_FREE_CMA_PAGES);
3497#endif
3498
3499	/*
3500	 * Fast check for order-0 only. If this fails then the reserves
3501	 * need to be calculated. There is a corner case where the check
3502	 * passes but only the high-order atomic reserve are free. If
3503	 * the caller is !atomic then it'll uselessly search the free
3504	 * list. That corner case is then slower but it is harmless.
3505	 */
3506	if (!order && (free_pages - cma_pages) > mark + z->lowmem_reserve[classzone_idx])
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3507		return true;
3508
3509	return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
3510					free_pages);
 
 
 
 
 
 
 
 
 
 
 
 
3511}
3512
3513bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
3514			unsigned long mark, int classzone_idx)
3515{
3516	long free_pages = zone_page_state(z, NR_FREE_PAGES);
3517
3518	if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
3519		free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
3520
3521	return __zone_watermark_ok(z, order, mark, classzone_idx, 0,
3522								free_pages);
3523}
3524
3525#ifdef CONFIG_NUMA
 
 
3526static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
3527{
3528	return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <=
3529				node_reclaim_distance;
3530}
3531#else	/* CONFIG_NUMA */
3532static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
3533{
3534	return true;
3535}
3536#endif	/* CONFIG_NUMA */
3537
3538/*
3539 * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid
3540 * fragmentation is subtle. If the preferred zone was HIGHMEM then
3541 * premature use of a lower zone may cause lowmem pressure problems that
3542 * are worse than fragmentation. If the next zone is ZONE_DMA then it is
3543 * probably too small. It only makes sense to spread allocations to avoid
3544 * fragmentation between the Normal and DMA32 zones.
3545 */
3546static inline unsigned int
3547alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
3548{
3549	unsigned int alloc_flags = 0;
3550
3551	if (gfp_mask & __GFP_KSWAPD_RECLAIM)
3552		alloc_flags |= ALLOC_KSWAPD;
 
 
 
3553
3554#ifdef CONFIG_ZONE_DMA32
3555	if (!zone)
3556		return alloc_flags;
3557
3558	if (zone_idx(zone) != ZONE_NORMAL)
3559		return alloc_flags;
3560
3561	/*
3562	 * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and
3563	 * the pointer is within zone->zone_pgdat->node_zones[]. Also assume
3564	 * on UMA that if Normal is populated then so is DMA32.
3565	 */
3566	BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1);
3567	if (nr_online_nodes > 1 && !populated_zone(--zone))
3568		return alloc_flags;
3569
3570	alloc_flags |= ALLOC_NOFRAGMENT;
3571#endif /* CONFIG_ZONE_DMA32 */
3572	return alloc_flags;
3573}
3574
 
 
 
 
 
 
 
 
 
 
 
3575/*
3576 * get_page_from_freelist goes through the zonelist trying to allocate
3577 * a page.
3578 */
3579static struct page *
3580get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
3581						const struct alloc_context *ac)
3582{
3583	struct zoneref *z;
3584	struct zone *zone;
3585	struct pglist_data *last_pgdat_dirty_limit = NULL;
 
3586	bool no_fallback;
3587
3588retry:
3589	/*
3590	 * Scan zonelist, looking for a zone with enough free.
3591	 * See also __cpuset_node_allowed() comment in kernel/cpuset.c.
3592	 */
3593	no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
3594	z = ac->preferred_zoneref;
3595	for_next_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
3596								ac->nodemask) {
3597		struct page *page;
3598		unsigned long mark;
3599
3600		if (cpusets_enabled() &&
3601			(alloc_flags & ALLOC_CPUSET) &&
3602			!__cpuset_zone_allowed(zone, gfp_mask))
3603				continue;
3604		/*
3605		 * When allocating a page cache page for writing, we
3606		 * want to get it from a node that is within its dirty
3607		 * limit, such that no single node holds more than its
3608		 * proportional share of globally allowed dirty pages.
3609		 * The dirty limits take into account the node's
3610		 * lowmem reserves and high watermark so that kswapd
3611		 * should be able to balance it without having to
3612		 * write pages from its LRU list.
3613		 *
3614		 * XXX: For now, allow allocations to potentially
3615		 * exceed the per-node dirty limit in the slowpath
3616		 * (spread_dirty_pages unset) before going into reclaim,
3617		 * which is important when on a NUMA setup the allowed
3618		 * nodes are together not big enough to reach the
3619		 * global limit.  The proper fix for these situations
3620		 * will require awareness of nodes in the
3621		 * dirty-throttling and the flusher threads.
3622		 */
3623		if (ac->spread_dirty_pages) {
3624			if (last_pgdat_dirty_limit == zone->zone_pgdat)
3625				continue;
 
 
3626
3627			if (!node_dirty_ok(zone->zone_pgdat)) {
3628				last_pgdat_dirty_limit = zone->zone_pgdat;
3629				continue;
3630			}
3631		}
3632
3633		if (no_fallback && nr_online_nodes > 1 &&
3634		    zone != ac->preferred_zoneref->zone) {
3635			int local_nid;
3636
3637			/*
3638			 * If moving to a remote node, retry but allow
3639			 * fragmenting fallbacks. Locality is more important
3640			 * than fragmentation avoidance.
3641			 */
3642			local_nid = zone_to_nid(ac->preferred_zoneref->zone);
3643			if (zone_to_nid(zone) != local_nid) {
3644				alloc_flags &= ~ALLOC_NOFRAGMENT;
3645				goto retry;
3646			}
3647		}
3648
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3649		mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
3650		if (!zone_watermark_fast(zone, order, mark,
3651				       ac_classzone_idx(ac), alloc_flags)) {
 
3652			int ret;
3653
 
 
 
 
 
3654#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
3655			/*
3656			 * Watermark failed for this zone, but see if we can
3657			 * grow this zone if it contains deferred pages.
3658			 */
3659			if (static_branch_unlikely(&deferred_pages)) {
3660				if (_deferred_grow_zone(zone, order))
3661					goto try_this_zone;
3662			}
3663#endif
3664			/* Checked here to keep the fast path fast */
3665			BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
3666			if (alloc_flags & ALLOC_NO_WATERMARKS)
3667				goto try_this_zone;
3668
3669			if (node_reclaim_mode == 0 ||
3670			    !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
3671				continue;
3672
3673			ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
3674			switch (ret) {
3675			case NODE_RECLAIM_NOSCAN:
3676				/* did not scan */
3677				continue;
3678			case NODE_RECLAIM_FULL:
3679				/* scanned but unreclaimable */
3680				continue;
3681			default:
3682				/* did we reclaim enough */
3683				if (zone_watermark_ok(zone, order, mark,
3684						ac_classzone_idx(ac), alloc_flags))
3685					goto try_this_zone;
3686
3687				continue;
3688			}
3689		}
3690
3691try_this_zone:
3692		page = rmqueue(ac->preferred_zoneref->zone, zone, order,
3693				gfp_mask, alloc_flags, ac->migratetype);
3694		if (page) {
3695			prep_new_page(page, order, gfp_mask, alloc_flags);
3696
3697			/*
3698			 * If this is a high-order atomic allocation then check
3699			 * if the pageblock should be reserved for the future
3700			 */
3701			if (unlikely(order && (alloc_flags & ALLOC_HARDER)))
3702				reserve_highatomic_pageblock(page, zone, order);
3703
3704			return page;
3705		} else {
 
 
 
 
 
3706#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
3707			/* Try again if zone has deferred pages */
3708			if (static_branch_unlikely(&deferred_pages)) {
3709				if (_deferred_grow_zone(zone, order))
3710					goto try_this_zone;
3711			}
3712#endif
3713		}
3714	}
3715
3716	/*
3717	 * It's possible on a UMA machine to get through all zones that are
3718	 * fragmented. If avoiding fragmentation, reset and try again.
3719	 */
3720	if (no_fallback) {
3721		alloc_flags &= ~ALLOC_NOFRAGMENT;
3722		goto retry;
3723	}
3724
3725	return NULL;
3726}
3727
3728static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask)
3729{
3730	unsigned int filter = SHOW_MEM_FILTER_NODES;
3731
3732	/*
3733	 * This documents exceptions given to allocations in certain
3734	 * contexts that are allowed to allocate outside current's set
3735	 * of allowed nodes.
3736	 */
3737	if (!(gfp_mask & __GFP_NOMEMALLOC))
3738		if (tsk_is_oom_victim(current) ||
3739		    (current->flags & (PF_MEMALLOC | PF_EXITING)))
3740			filter &= ~SHOW_MEM_FILTER_NODES;
3741	if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
3742		filter &= ~SHOW_MEM_FILTER_NODES;
3743
3744	show_mem(filter, nodemask);
3745}
3746
3747void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)
3748{
3749	struct va_format vaf;
3750	va_list args;
3751	static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1);
3752
3753	if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs))
 
 
3754		return;
3755
3756	va_start(args, fmt);
3757	vaf.fmt = fmt;
3758	vaf.va = &args;
3759	pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl",
3760			current->comm, &vaf, gfp_mask, &gfp_mask,
3761			nodemask_pr_args(nodemask));
3762	va_end(args);
3763
3764	cpuset_print_current_mems_allowed();
3765	pr_cont("\n");
3766	dump_stack();
3767	warn_alloc_show_mem(gfp_mask, nodemask);
3768}
3769
3770static inline struct page *
3771__alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order,
3772			      unsigned int alloc_flags,
3773			      const struct alloc_context *ac)
3774{
3775	struct page *page;
3776
3777	page = get_page_from_freelist(gfp_mask, order,
3778			alloc_flags|ALLOC_CPUSET, ac);
3779	/*
3780	 * fallback to ignore cpuset restriction if our nodes
3781	 * are depleted
3782	 */
3783	if (!page)
3784		page = get_page_from_freelist(gfp_mask, order,
3785				alloc_flags, ac);
3786
3787	return page;
3788}
3789
3790static inline struct page *
3791__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
3792	const struct alloc_context *ac, unsigned long *did_some_progress)
3793{
3794	struct oom_control oc = {
3795		.zonelist = ac->zonelist,
3796		.nodemask = ac->nodemask,
3797		.memcg = NULL,
3798		.gfp_mask = gfp_mask,
3799		.order = order,
3800	};
3801	struct page *page;
3802
3803	*did_some_progress = 0;
3804
3805	/*
3806	 * Acquire the oom lock.  If that fails, somebody else is
3807	 * making progress for us.
3808	 */
3809	if (!mutex_trylock(&oom_lock)) {
3810		*did_some_progress = 1;
3811		schedule_timeout_uninterruptible(1);
3812		return NULL;
3813	}
3814
3815	/*
3816	 * Go through the zonelist yet one more time, keep very high watermark
3817	 * here, this is only to catch a parallel oom killing, we must fail if
3818	 * we're still under heavy pressure. But make sure that this reclaim
3819	 * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY
3820	 * allocation which will never fail due to oom_lock already held.
3821	 */
3822	page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) &
3823				      ~__GFP_DIRECT_RECLAIM, order,
3824				      ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
3825	if (page)
3826		goto out;
3827
3828	/* Coredumps can quickly deplete all memory reserves */
3829	if (current->flags & PF_DUMPCORE)
3830		goto out;
3831	/* The OOM killer will not help higher order allocs */
3832	if (order > PAGE_ALLOC_COSTLY_ORDER)
3833		goto out;
3834	/*
3835	 * We have already exhausted all our reclaim opportunities without any
3836	 * success so it is time to admit defeat. We will skip the OOM killer
3837	 * because it is very likely that the caller has a more reasonable
3838	 * fallback than shooting a random task.
 
 
3839	 */
3840	if (gfp_mask & __GFP_RETRY_MAYFAIL)
3841		goto out;
3842	/* The OOM killer does not needlessly kill tasks for lowmem */
3843	if (ac->high_zoneidx < ZONE_NORMAL)
3844		goto out;
3845	if (pm_suspended_storage())
3846		goto out;
3847	/*
3848	 * XXX: GFP_NOFS allocations should rather fail than rely on
3849	 * other request to make a forward progress.
3850	 * We are in an unfortunate situation where out_of_memory cannot
3851	 * do much for this context but let's try it to at least get
3852	 * access to memory reserved if the current task is killed (see
3853	 * out_of_memory). Once filesystems are ready to handle allocation
3854	 * failures more gracefully we should just bail out here.
3855	 */
3856
3857	/* The OOM killer may not free memory on a specific node */
3858	if (gfp_mask & __GFP_THISNODE)
3859		goto out;
3860
3861	/* Exhausted what can be done so it's blame time */
3862	if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
 
3863		*did_some_progress = 1;
3864
3865		/*
3866		 * Help non-failing allocations by giving them access to memory
3867		 * reserves
3868		 */
3869		if (gfp_mask & __GFP_NOFAIL)
3870			page = __alloc_pages_cpuset_fallback(gfp_mask, order,
3871					ALLOC_NO_WATERMARKS, ac);
3872	}
3873out:
3874	mutex_unlock(&oom_lock);
3875	return page;
3876}
3877
3878/*
3879 * Maximum number of compaction retries wit a progress before OOM
3880 * killer is consider as the only way to move forward.
3881 */
3882#define MAX_COMPACT_RETRIES 16
3883
3884#ifdef CONFIG_COMPACTION
3885/* Try memory compaction for high-order allocations before reclaim */
3886static struct page *
3887__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
3888		unsigned int alloc_flags, const struct alloc_context *ac,
3889		enum compact_priority prio, enum compact_result *compact_result)
3890{
3891	struct page *page = NULL;
3892	unsigned long pflags;
3893	unsigned int noreclaim_flag;
3894
3895	if (!order)
3896		return NULL;
3897
3898	psi_memstall_enter(&pflags);
 
3899	noreclaim_flag = memalloc_noreclaim_save();
3900
3901	*compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
3902								prio, &page);
3903
3904	memalloc_noreclaim_restore(noreclaim_flag);
3905	psi_memstall_leave(&pflags);
 
3906
 
 
3907	/*
3908	 * At least in one zone compaction wasn't deferred or skipped, so let's
3909	 * count a compaction stall
3910	 */
3911	count_vm_event(COMPACTSTALL);
3912
3913	/* Prep a captured page if available */
3914	if (page)
3915		prep_new_page(page, order, gfp_mask, alloc_flags);
3916
3917	/* Try get a page from the freelist if available */
3918	if (!page)
3919		page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3920
3921	if (page) {
3922		struct zone *zone = page_zone(page);
3923
3924		zone->compact_blockskip_flush = false;
3925		compaction_defer_reset(zone, order, true);
3926		count_vm_event(COMPACTSUCCESS);
3927		return page;
3928	}
3929
3930	/*
3931	 * It's bad if compaction run occurs and fails. The most likely reason
3932	 * is that pages exist, but not enough to satisfy watermarks.
3933	 */
3934	count_vm_event(COMPACTFAIL);
3935
3936	cond_resched();
3937
3938	return NULL;
3939}
3940
3941static inline bool
3942should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
3943		     enum compact_result compact_result,
3944		     enum compact_priority *compact_priority,
3945		     int *compaction_retries)
3946{
3947	int max_retries = MAX_COMPACT_RETRIES;
3948	int min_priority;
3949	bool ret = false;
3950	int retries = *compaction_retries;
3951	enum compact_priority priority = *compact_priority;
3952
3953	if (!order)
3954		return false;
3955
3956	if (compaction_made_progress(compact_result))
3957		(*compaction_retries)++;
3958
3959	/*
3960	 * compaction considers all the zone as desperately out of memory
3961	 * so it doesn't really make much sense to retry except when the
3962	 * failure could be caused by insufficient priority
3963	 */
3964	if (compaction_failed(compact_result))
3965		goto check_priority;
3966
3967	/*
3968	 * compaction was skipped because there are not enough order-0 pages
3969	 * to work with, so we retry only if it looks like reclaim can help.
3970	 */
3971	if (compaction_needs_reclaim(compact_result)) {
3972		ret = compaction_zonelist_suitable(ac, order, alloc_flags);
3973		goto out;
3974	}
3975
3976	/*
3977	 * make sure the compaction wasn't deferred or didn't bail out early
3978	 * due to locks contention before we declare that we should give up.
3979	 * But the next retry should use a higher priority if allowed, so
3980	 * we don't just keep bailing out endlessly.
3981	 */
3982	if (compaction_withdrawn(compact_result)) {
3983		goto check_priority;
3984	}
3985
3986	/*
3987	 * !costly requests are much more important than __GFP_RETRY_MAYFAIL
3988	 * costly ones because they are de facto nofail and invoke OOM
3989	 * killer to move on while costly can fail and users are ready
3990	 * to cope with that. 1/4 retries is rather arbitrary but we
3991	 * would need much more detailed feedback from compaction to
3992	 * make a better decision.
3993	 */
3994	if (order > PAGE_ALLOC_COSTLY_ORDER)
3995		max_retries /= 4;
3996	if (*compaction_retries <= max_retries) {
3997		ret = true;
3998		goto out;
 
 
 
 
 
 
 
 
 
 
 
 
3999	}
4000
4001	/*
4002	 * Make sure there are attempts at the highest priority if we exhausted
4003	 * all retries or failed at the lower priorities.
4004	 */
4005check_priority:
4006	min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ?
4007			MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;
4008
4009	if (*compact_priority > min_priority) {
4010		(*compact_priority)--;
4011		*compaction_retries = 0;
4012		ret = true;
4013	}
4014out:
4015	trace_compact_retry(order, priority, compact_result, retries, max_retries, ret);
4016	return ret;
4017}
4018#else
4019static inline struct page *
4020__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
4021		unsigned int alloc_flags, const struct alloc_context *ac,
4022		enum compact_priority prio, enum compact_result *compact_result)
4023{
4024	*compact_result = COMPACT_SKIPPED;
4025	return NULL;
4026}
4027
4028static inline bool
4029should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
4030		     enum compact_result compact_result,
4031		     enum compact_priority *compact_priority,
4032		     int *compaction_retries)
4033{
4034	struct zone *zone;
4035	struct zoneref *z;
4036
4037	if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
4038		return false;
4039
4040	/*
4041	 * There are setups with compaction disabled which would prefer to loop
4042	 * inside the allocator rather than hit the oom killer prematurely.
4043	 * Let's give them a good hope and keep retrying while the order-0
4044	 * watermarks are OK.
4045	 */
4046	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
4047					ac->nodemask) {
4048		if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
4049					ac_classzone_idx(ac), alloc_flags))
4050			return true;
4051	}
4052	return false;
4053}
4054#endif /* CONFIG_COMPACTION */
4055
4056#ifdef CONFIG_LOCKDEP
4057static struct lockdep_map __fs_reclaim_map =
4058	STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map);
4059
4060static bool __need_fs_reclaim(gfp_t gfp_mask)
4061{
4062	gfp_mask = current_gfp_context(gfp_mask);
4063
4064	/* no reclaim without waiting on it */
4065	if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
4066		return false;
4067
4068	/* this guy won't enter reclaim */
4069	if (current->flags & PF_MEMALLOC)
4070		return false;
4071
4072	/* We're only interested __GFP_FS allocations for now */
4073	if (!(gfp_mask & __GFP_FS))
4074		return false;
4075
4076	if (gfp_mask & __GFP_NOLOCKDEP)
4077		return false;
4078
4079	return true;
4080}
4081
4082void __fs_reclaim_acquire(void)
4083{
4084	lock_map_acquire(&__fs_reclaim_map);
4085}
4086
4087void __fs_reclaim_release(void)
4088{
4089	lock_map_release(&__fs_reclaim_map);
4090}
4091
4092void fs_reclaim_acquire(gfp_t gfp_mask)
4093{
4094	if (__need_fs_reclaim(gfp_mask))
4095		__fs_reclaim_acquire();
 
 
 
 
 
 
 
 
 
 
4096}
4097EXPORT_SYMBOL_GPL(fs_reclaim_acquire);
4098
4099void fs_reclaim_release(gfp_t gfp_mask)
4100{
4101	if (__need_fs_reclaim(gfp_mask))
4102		__fs_reclaim_release();
 
 
 
 
4103}
4104EXPORT_SYMBOL_GPL(fs_reclaim_release);
4105#endif
4106
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4107/* Perform direct synchronous page reclaim */
4108static int
4109__perform_reclaim(gfp_t gfp_mask, unsigned int order,
4110					const struct alloc_context *ac)
4111{
4112	int progress;
4113	unsigned int noreclaim_flag;
4114	unsigned long pflags;
4115
4116	cond_resched();
4117
4118	/* We now go into synchronous reclaim */
4119	cpuset_memory_pressure_bump();
4120	psi_memstall_enter(&pflags);
4121	fs_reclaim_acquire(gfp_mask);
4122	noreclaim_flag = memalloc_noreclaim_save();
4123
4124	progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
4125								ac->nodemask);
4126
4127	memalloc_noreclaim_restore(noreclaim_flag);
4128	fs_reclaim_release(gfp_mask);
4129	psi_memstall_leave(&pflags);
4130
4131	cond_resched();
4132
4133	return progress;
4134}
4135
4136/* The really slow allocator path where we enter direct reclaim */
4137static inline struct page *
4138__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
4139		unsigned int alloc_flags, const struct alloc_context *ac,
4140		unsigned long *did_some_progress)
4141{
4142	struct page *page = NULL;
 
4143	bool drained = false;
4144
 
4145	*did_some_progress = __perform_reclaim(gfp_mask, order, ac);
4146	if (unlikely(!(*did_some_progress)))
4147		return NULL;
4148
4149retry:
4150	page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4151
4152	/*
4153	 * If an allocation failed after direct reclaim, it could be because
4154	 * pages are pinned on the per-cpu lists or in high alloc reserves.
4155	 * Shrink them them and try again
4156	 */
4157	if (!page && !drained) {
4158		unreserve_highatomic_pageblock(ac, false);
4159		drain_all_pages(NULL);
4160		drained = true;
4161		goto retry;
4162	}
 
 
4163
4164	return page;
4165}
4166
4167static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
4168			     const struct alloc_context *ac)
4169{
4170	struct zoneref *z;
4171	struct zone *zone;
4172	pg_data_t *last_pgdat = NULL;
4173	enum zone_type high_zoneidx = ac->high_zoneidx;
4174
4175	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, high_zoneidx,
4176					ac->nodemask) {
4177		if (last_pgdat != zone->zone_pgdat)
4178			wakeup_kswapd(zone, gfp_mask, order, high_zoneidx);
4179		last_pgdat = zone->zone_pgdat;
 
 
 
4180	}
4181}
4182
4183static inline unsigned int
4184gfp_to_alloc_flags(gfp_t gfp_mask)
4185{
4186	unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
4187
4188	/* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
4189	BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
 
 
 
 
 
4190
4191	/*
4192	 * The caller may dip into page reserves a bit more if the caller
4193	 * cannot run direct reclaim, or if the caller has realtime scheduling
4194	 * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
4195	 * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
4196	 */
4197	alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
 
4198
4199	if (gfp_mask & __GFP_ATOMIC) {
4200		/*
4201		 * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
4202		 * if it can't schedule.
4203		 */
4204		if (!(gfp_mask & __GFP_NOMEMALLOC))
4205			alloc_flags |= ALLOC_HARDER;
 
 
 
 
 
4206		/*
4207		 * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
4208		 * comment for __cpuset_node_allowed().
 
4209		 */
4210		alloc_flags &= ~ALLOC_CPUSET;
4211	} else if (unlikely(rt_task(current)) && !in_interrupt())
4212		alloc_flags |= ALLOC_HARDER;
 
4213
4214	if (gfp_mask & __GFP_KSWAPD_RECLAIM)
4215		alloc_flags |= ALLOC_KSWAPD;
4216
4217#ifdef CONFIG_CMA
4218	if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
4219		alloc_flags |= ALLOC_CMA;
4220#endif
4221	return alloc_flags;
4222}
4223
4224static bool oom_reserves_allowed(struct task_struct *tsk)
4225{
4226	if (!tsk_is_oom_victim(tsk))
4227		return false;
4228
4229	/*
4230	 * !MMU doesn't have oom reaper so give access to memory reserves
4231	 * only to the thread with TIF_MEMDIE set
4232	 */
4233	if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE))
4234		return false;
4235
4236	return true;
4237}
4238
4239/*
4240 * Distinguish requests which really need access to full memory
4241 * reserves from oom victims which can live with a portion of it
4242 */
4243static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask)
4244{
4245	if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
4246		return 0;
4247	if (gfp_mask & __GFP_MEMALLOC)
4248		return ALLOC_NO_WATERMARKS;
4249	if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
4250		return ALLOC_NO_WATERMARKS;
4251	if (!in_interrupt()) {
4252		if (current->flags & PF_MEMALLOC)
4253			return ALLOC_NO_WATERMARKS;
4254		else if (oom_reserves_allowed(current))
4255			return ALLOC_OOM;
4256	}
4257
4258	return 0;
4259}
4260
4261bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
4262{
4263	return !!__gfp_pfmemalloc_flags(gfp_mask);
4264}
4265
4266/*
4267 * Checks whether it makes sense to retry the reclaim to make a forward progress
4268 * for the given allocation request.
4269 *
4270 * We give up when we either have tried MAX_RECLAIM_RETRIES in a row
4271 * without success, or when we couldn't even meet the watermark if we
4272 * reclaimed all remaining pages on the LRU lists.
4273 *
4274 * Returns true if a retry is viable or false to enter the oom path.
4275 */
4276static inline bool
4277should_reclaim_retry(gfp_t gfp_mask, unsigned order,
4278		     struct alloc_context *ac, int alloc_flags,
4279		     bool did_some_progress, int *no_progress_loops)
4280{
4281	struct zone *zone;
4282	struct zoneref *z;
4283	bool ret = false;
4284
4285	/*
4286	 * Costly allocations might have made a progress but this doesn't mean
4287	 * their order will become available due to high fragmentation so
4288	 * always increment the no progress counter for them
4289	 */
4290	if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
4291		*no_progress_loops = 0;
4292	else
4293		(*no_progress_loops)++;
4294
4295	/*
4296	 * Make sure we converge to OOM if we cannot make any progress
4297	 * several times in the row.
4298	 */
4299	if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
4300		/* Before OOM, exhaust highatomic_reserve */
4301		return unreserve_highatomic_pageblock(ac, true);
4302	}
4303
4304	/*
4305	 * Keep reclaiming pages while there is a chance this will lead
4306	 * somewhere.  If none of the target zones can satisfy our allocation
4307	 * request even if all reclaimable pages are considered then we are
4308	 * screwed and have to go OOM.
4309	 */
4310	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
4311					ac->nodemask) {
4312		unsigned long available;
4313		unsigned long reclaimable;
4314		unsigned long min_wmark = min_wmark_pages(zone);
4315		bool wmark;
4316
4317		available = reclaimable = zone_reclaimable_pages(zone);
4318		available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
4319
4320		/*
4321		 * Would the allocation succeed if we reclaimed all
4322		 * reclaimable pages?
4323		 */
4324		wmark = __zone_watermark_ok(zone, order, min_wmark,
4325				ac_classzone_idx(ac), alloc_flags, available);
4326		trace_reclaim_retry_zone(z, order, reclaimable,
4327				available, min_wmark, *no_progress_loops, wmark);
4328		if (wmark) {
4329			/*
4330			 * If we didn't make any progress and have a lot of
4331			 * dirty + writeback pages then we should wait for
4332			 * an IO to complete to slow down the reclaim and
4333			 * prevent from pre mature OOM
4334			 */
4335			if (!did_some_progress) {
4336				unsigned long write_pending;
4337
4338				write_pending = zone_page_state_snapshot(zone,
4339							NR_ZONE_WRITE_PENDING);
4340
4341				if (2 * write_pending > reclaimable) {
4342					congestion_wait(BLK_RW_ASYNC, HZ/10);
4343					return true;
4344				}
4345			}
4346
4347			ret = true;
4348			goto out;
4349		}
4350	}
4351
4352out:
4353	/*
4354	 * Memory allocation/reclaim might be called from a WQ context and the
4355	 * current implementation of the WQ concurrency control doesn't
4356	 * recognize that a particular WQ is congested if the worker thread is
4357	 * looping without ever sleeping. Therefore we have to do a short sleep
4358	 * here rather than calling cond_resched().
4359	 */
4360	if (current->flags & PF_WQ_WORKER)
4361		schedule_timeout_uninterruptible(1);
4362	else
4363		cond_resched();
 
 
 
 
 
4364	return ret;
4365}
4366
4367static inline bool
4368check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac)
4369{
4370	/*
4371	 * It's possible that cpuset's mems_allowed and the nodemask from
4372	 * mempolicy don't intersect. This should be normally dealt with by
4373	 * policy_nodemask(), but it's possible to race with cpuset update in
4374	 * such a way the check therein was true, and then it became false
4375	 * before we got our cpuset_mems_cookie here.
4376	 * This assumes that for all allocations, ac->nodemask can come only
4377	 * from MPOL_BIND mempolicy (whose documented semantics is to be ignored
4378	 * when it does not intersect with the cpuset restrictions) or the
4379	 * caller can deal with a violated nodemask.
4380	 */
4381	if (cpusets_enabled() && ac->nodemask &&
4382			!cpuset_nodemask_valid_mems_allowed(ac->nodemask)) {
4383		ac->nodemask = NULL;
4384		return true;
4385	}
4386
4387	/*
4388	 * When updating a task's mems_allowed or mempolicy nodemask, it is
4389	 * possible to race with parallel threads in such a way that our
4390	 * allocation can fail while the mask is being updated. If we are about
4391	 * to fail, check if the cpuset changed during allocation and if so,
4392	 * retry.
4393	 */
4394	if (read_mems_allowed_retry(cpuset_mems_cookie))
4395		return true;
4396
4397	return false;
4398}
4399
4400static inline struct page *
4401__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
4402						struct alloc_context *ac)
4403{
4404	bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
 
4405	const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER;
4406	struct page *page = NULL;
4407	unsigned int alloc_flags;
4408	unsigned long did_some_progress;
4409	enum compact_priority compact_priority;
4410	enum compact_result compact_result;
4411	int compaction_retries;
4412	int no_progress_loops;
4413	unsigned int cpuset_mems_cookie;
 
4414	int reserve_flags;
4415
4416	/*
4417	 * We also sanity check to catch abuse of atomic reserves being used by
4418	 * callers that are not in atomic context.
4419	 */
4420	if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) ==
4421				(__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
4422		gfp_mask &= ~__GFP_ATOMIC;
4423
4424retry_cpuset:
4425	compaction_retries = 0;
4426	no_progress_loops = 0;
4427	compact_priority = DEF_COMPACT_PRIORITY;
4428	cpuset_mems_cookie = read_mems_allowed_begin();
 
4429
4430	/*
4431	 * The fast path uses conservative alloc_flags to succeed only until
4432	 * kswapd needs to be woken up, and to avoid the cost of setting up
4433	 * alloc_flags precisely. So we do that now.
4434	 */
4435	alloc_flags = gfp_to_alloc_flags(gfp_mask);
4436
4437	/*
4438	 * We need to recalculate the starting point for the zonelist iterator
4439	 * because we might have used different nodemask in the fast path, or
4440	 * there was a cpuset modification and we are retrying - otherwise we
4441	 * could end up iterating over non-eligible zones endlessly.
4442	 */
4443	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4444					ac->high_zoneidx, ac->nodemask);
4445	if (!ac->preferred_zoneref->zone)
4446		goto nopage;
4447
 
 
 
 
 
 
 
 
 
 
 
 
 
4448	if (alloc_flags & ALLOC_KSWAPD)
4449		wake_all_kswapds(order, gfp_mask, ac);
4450
4451	/*
4452	 * The adjusted alloc_flags might result in immediate success, so try
4453	 * that first
4454	 */
4455	page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4456	if (page)
4457		goto got_pg;
4458
4459	/*
4460	 * For costly allocations, try direct compaction first, as it's likely
4461	 * that we have enough base pages and don't need to reclaim. For non-
4462	 * movable high-order allocations, do that as well, as compaction will
4463	 * try prevent permanent fragmentation by migrating from blocks of the
4464	 * same migratetype.
4465	 * Don't try this for allocations that are allowed to ignore
4466	 * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen.
4467	 */
4468	if (can_direct_reclaim &&
4469			(costly_order ||
4470			   (order > 0 && ac->migratetype != MIGRATE_MOVABLE))
4471			&& !gfp_pfmemalloc_allowed(gfp_mask)) {
4472		page = __alloc_pages_direct_compact(gfp_mask, order,
4473						alloc_flags, ac,
4474						INIT_COMPACT_PRIORITY,
4475						&compact_result);
4476		if (page)
4477			goto got_pg;
4478
4479		 if (order >= pageblock_order && (gfp_mask & __GFP_IO) &&
4480		     !(gfp_mask & __GFP_RETRY_MAYFAIL)) {
 
 
 
4481			/*
4482			 * If allocating entire pageblock(s) and compaction
4483			 * failed because all zones are below low watermarks
4484			 * or is prohibited because it recently failed at this
4485			 * order, fail immediately unless the allocator has
4486			 * requested compaction and reclaim retry.
4487			 *
4488			 * Reclaim is
4489			 *  - potentially very expensive because zones are far
4490			 *    below their low watermarks or this is part of very
4491			 *    bursty high order allocations,
4492			 *  - not guaranteed to help because isolate_freepages()
4493			 *    may not iterate over freed pages as part of its
4494			 *    linear scan, and
4495			 *  - unlikely to make entire pageblocks free on its
4496			 *    own.
4497			 */
4498			if (compact_result == COMPACT_SKIPPED ||
4499			    compact_result == COMPACT_DEFERRED)
4500				goto nopage;
4501		}
4502
4503		/*
4504		 * Checks for costly allocations with __GFP_NORETRY, which
4505		 * includes THP page fault allocations
4506		 */
4507		if (costly_order && (gfp_mask & __GFP_NORETRY)) {
4508			/*
4509			 * If compaction is deferred for high-order allocations,
4510			 * it is because sync compaction recently failed. If
4511			 * this is the case and the caller requested a THP
4512			 * allocation, we do not want to heavily disrupt the
4513			 * system, so we fail the allocation instead of entering
4514			 * direct reclaim.
4515			 */
4516			if (compact_result == COMPACT_DEFERRED)
4517				goto nopage;
4518
4519			/*
4520			 * Looks like reclaim/compaction is worth trying, but
4521			 * sync compaction could be very expensive, so keep
4522			 * using async compaction.
4523			 */
4524			compact_priority = INIT_COMPACT_PRIORITY;
4525		}
4526	}
4527
4528retry:
4529	/* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
4530	if (alloc_flags & ALLOC_KSWAPD)
4531		wake_all_kswapds(order, gfp_mask, ac);
4532
4533	reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
4534	if (reserve_flags)
4535		alloc_flags = reserve_flags;
 
4536
4537	/*
4538	 * Reset the nodemask and zonelist iterators if memory policies can be
4539	 * ignored. These allocations are high priority and system rather than
4540	 * user oriented.
4541	 */
4542	if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) {
4543		ac->nodemask = NULL;
4544		ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4545					ac->high_zoneidx, ac->nodemask);
4546	}
4547
4548	/* Attempt with potentially adjusted zonelist and alloc_flags */
4549	page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4550	if (page)
4551		goto got_pg;
4552
4553	/* Caller is not willing to reclaim, we can't balance anything */
4554	if (!can_direct_reclaim)
4555		goto nopage;
4556
4557	/* Avoid recursion of direct reclaim */
4558	if (current->flags & PF_MEMALLOC)
4559		goto nopage;
4560
4561	/* Try direct reclaim and then allocating */
4562	page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
4563							&did_some_progress);
4564	if (page)
4565		goto got_pg;
4566
4567	/* Try direct compaction and then allocating */
4568	page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
4569					compact_priority, &compact_result);
4570	if (page)
4571		goto got_pg;
4572
4573	/* Do not loop if specifically requested */
4574	if (gfp_mask & __GFP_NORETRY)
4575		goto nopage;
4576
4577	/*
4578	 * Do not retry costly high order allocations unless they are
4579	 * __GFP_RETRY_MAYFAIL
4580	 */
4581	if (costly_order && !(gfp_mask & __GFP_RETRY_MAYFAIL))
 
4582		goto nopage;
4583
4584	if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
4585				 did_some_progress > 0, &no_progress_loops))
4586		goto retry;
4587
4588	/*
4589	 * It doesn't make any sense to retry for the compaction if the order-0
4590	 * reclaim is not able to make any progress because the current
4591	 * implementation of the compaction depends on the sufficient amount
4592	 * of free memory (see __compaction_suitable)
4593	 */
4594	if (did_some_progress > 0 &&
4595			should_compact_retry(ac, order, alloc_flags,
4596				compact_result, &compact_priority,
4597				&compaction_retries))
4598		goto retry;
4599
4600
4601	/* Deal with possible cpuset update races before we start OOM killing */
4602	if (check_retry_cpuset(cpuset_mems_cookie, ac))
4603		goto retry_cpuset;
 
 
 
 
4604
4605	/* Reclaim has failed us, start killing things */
4606	page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
4607	if (page)
4608		goto got_pg;
4609
4610	/* Avoid allocations with no watermarks from looping endlessly */
4611	if (tsk_is_oom_victim(current) &&
4612	    (alloc_flags == ALLOC_OOM ||
4613	     (gfp_mask & __GFP_NOMEMALLOC)))
4614		goto nopage;
4615
4616	/* Retry as long as the OOM killer is making progress */
4617	if (did_some_progress) {
4618		no_progress_loops = 0;
4619		goto retry;
4620	}
4621
4622nopage:
4623	/* Deal with possible cpuset update races before we fail */
4624	if (check_retry_cpuset(cpuset_mems_cookie, ac))
4625		goto retry_cpuset;
 
 
 
 
4626
4627	/*
4628	 * Make sure that __GFP_NOFAIL request doesn't leak out and make sure
4629	 * we always retry
4630	 */
4631	if (gfp_mask & __GFP_NOFAIL) {
4632		/*
4633		 * All existing users of the __GFP_NOFAIL are blockable, so warn
4634		 * of any new users that actually require GFP_NOWAIT
4635		 */
4636		if (WARN_ON_ONCE(!can_direct_reclaim))
4637			goto fail;
4638
4639		/*
4640		 * PF_MEMALLOC request from this context is rather bizarre
4641		 * because we cannot reclaim anything and only can loop waiting
4642		 * for somebody to do a work for us
4643		 */
4644		WARN_ON_ONCE(current->flags & PF_MEMALLOC);
4645
4646		/*
4647		 * non failing costly orders are a hard requirement which we
4648		 * are not prepared for much so let's warn about these users
4649		 * so that we can identify them and convert them to something
4650		 * else.
4651		 */
4652		WARN_ON_ONCE(order > PAGE_ALLOC_COSTLY_ORDER);
4653
4654		/*
4655		 * Help non-failing allocations by giving them access to memory
4656		 * reserves but do not use ALLOC_NO_WATERMARKS because this
 
4657		 * could deplete whole memory reserves which would just make
4658		 * the situation worse
4659		 */
4660		page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_HARDER, ac);
4661		if (page)
4662			goto got_pg;
4663
4664		cond_resched();
4665		goto retry;
4666	}
4667fail:
4668	warn_alloc(gfp_mask, ac->nodemask,
4669			"page allocation failure: order:%u", order);
4670got_pg:
4671	return page;
4672}
4673
4674static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
4675		int preferred_nid, nodemask_t *nodemask,
4676		struct alloc_context *ac, gfp_t *alloc_mask,
4677		unsigned int *alloc_flags)
4678{
4679	ac->high_zoneidx = gfp_zone(gfp_mask);
4680	ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
4681	ac->nodemask = nodemask;
4682	ac->migratetype = gfpflags_to_migratetype(gfp_mask);
4683
4684	if (cpusets_enabled()) {
4685		*alloc_mask |= __GFP_HARDWALL;
4686		if (!ac->nodemask)
 
 
 
 
4687			ac->nodemask = &cpuset_current_mems_allowed;
4688		else
4689			*alloc_flags |= ALLOC_CPUSET;
4690	}
4691
4692	fs_reclaim_acquire(gfp_mask);
4693	fs_reclaim_release(gfp_mask);
4694
4695	might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
4696
4697	if (should_fail_alloc_page(gfp_mask, order))
4698		return false;
4699
4700	if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE)
4701		*alloc_flags |= ALLOC_CMA;
4702
4703	return true;
4704}
4705
4706/* Determine whether to spread dirty pages and what the first usable zone */
4707static inline void finalise_ac(gfp_t gfp_mask, struct alloc_context *ac)
4708{
4709	/* Dirty zone balancing only done in the fast path */
4710	ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
4711
4712	/*
4713	 * The preferred zone is used for statistics but crucially it is
4714	 * also used as the starting point for the zonelist iterator. It
4715	 * may get reset for allocations that ignore memory policies.
4716	 */
4717	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4718					ac->high_zoneidx, ac->nodemask);
 
 
4719}
4720
4721/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4722 * This is the 'heart' of the zoned buddy allocator.
4723 */
4724struct page *
4725__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
4726							nodemask_t *nodemask)
4727{
4728	struct page *page;
4729	unsigned int alloc_flags = ALLOC_WMARK_LOW;
4730	gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */
4731	struct alloc_context ac = { };
4732
4733	/*
4734	 * There are several places where we assume that the order value is sane
4735	 * so bail out early if the request is out of bound.
4736	 */
4737	if (unlikely(order >= MAX_ORDER)) {
4738		WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
4739		return NULL;
4740	}
4741
4742	gfp_mask &= gfp_allowed_mask;
4743	alloc_mask = gfp_mask;
4744	if (!prepare_alloc_pages(gfp_mask, order, preferred_nid, nodemask, &ac, &alloc_mask, &alloc_flags))
 
 
 
 
 
 
 
 
 
4745		return NULL;
4746
4747	finalise_ac(gfp_mask, &ac);
4748
4749	/*
4750	 * Forbid the first pass from falling back to types that fragment
4751	 * memory until all local zones are considered.
4752	 */
4753	alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp_mask);
4754
4755	/* First allocation attempt */
4756	page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
4757	if (likely(page))
4758		goto out;
4759
4760	/*
4761	 * Apply scoped allocation constraints. This is mainly about GFP_NOFS
4762	 * resp. GFP_NOIO which has to be inherited for all allocation requests
4763	 * from a particular context which has been marked by
4764	 * memalloc_no{fs,io}_{save,restore}.
4765	 */
4766	alloc_mask = current_gfp_context(gfp_mask);
4767	ac.spread_dirty_pages = false;
4768
4769	/*
4770	 * Restore the original nodemask if it was potentially replaced with
4771	 * &cpuset_current_mems_allowed to optimize the fast-path attempt.
4772	 */
4773	if (unlikely(ac.nodemask != nodemask))
4774		ac.nodemask = nodemask;
4775
4776	page = __alloc_pages_slowpath(alloc_mask, order, &ac);
4777
4778out:
4779	if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
4780	    unlikely(__memcg_kmem_charge(page, gfp_mask, order) != 0)) {
4781		__free_pages(page, order);
4782		page = NULL;
4783	}
4784
4785	trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);
 
4786
4787	return page;
4788}
4789EXPORT_SYMBOL(__alloc_pages_nodemask);
 
 
 
 
 
 
 
 
 
4790
4791/*
4792 * Common helper functions. Never use with __GFP_HIGHMEM because the returned
4793 * address cannot represent highmem pages. Use alloc_pages and then kmap if
4794 * you need to access high mem.
4795 */
4796unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
4797{
4798	struct page *page;
4799
4800	page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, order);
4801	if (!page)
4802		return 0;
4803	return (unsigned long) page_address(page);
4804}
4805EXPORT_SYMBOL(__get_free_pages);
4806
4807unsigned long get_zeroed_page(gfp_t gfp_mask)
4808{
4809	return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
4810}
4811EXPORT_SYMBOL(get_zeroed_page);
4812
4813static inline void free_the_page(struct page *page, unsigned int order)
4814{
4815	if (order == 0)		/* Via pcp? */
4816		free_unref_page(page);
4817	else
4818		__free_pages_ok(page, order);
4819}
4820
 
 
 
 
 
 
 
 
 
 
 
 
4821void __free_pages(struct page *page, unsigned int order)
4822{
 
 
 
4823	if (put_page_testzero(page))
4824		free_the_page(page, order);
 
 
 
4825}
4826EXPORT_SYMBOL(__free_pages);
4827
4828void free_pages(unsigned long addr, unsigned int order)
4829{
4830	if (addr != 0) {
4831		VM_BUG_ON(!virt_addr_valid((void *)addr));
4832		__free_pages(virt_to_page((void *)addr), order);
4833	}
4834}
4835
4836EXPORT_SYMBOL(free_pages);
4837
4838/*
4839 * Page Fragment:
4840 *  An arbitrary-length arbitrary-offset area of memory which resides
4841 *  within a 0 or higher order page.  Multiple fragments within that page
4842 *  are individually refcounted, in the page's reference counter.
4843 *
4844 * The page_frag functions below provide a simple allocation framework for
4845 * page fragments.  This is used by the network stack and network device
4846 * drivers to provide a backing region of memory for use as either an
4847 * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
4848 */
4849static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
4850					     gfp_t gfp_mask)
4851{
4852	struct page *page = NULL;
4853	gfp_t gfp = gfp_mask;
4854
4855#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4856	gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
4857		    __GFP_NOMEMALLOC;
4858	page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
4859				PAGE_FRAG_CACHE_MAX_ORDER);
4860	nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
4861#endif
4862	if (unlikely(!page))
4863		page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
4864
4865	nc->va = page ? page_address(page) : NULL;
4866
4867	return page;
4868}
4869
4870void __page_frag_cache_drain(struct page *page, unsigned int count)
4871{
4872	VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
4873
4874	if (page_ref_sub_and_test(page, count))
4875		free_the_page(page, compound_order(page));
4876}
4877EXPORT_SYMBOL(__page_frag_cache_drain);
4878
4879void *page_frag_alloc(struct page_frag_cache *nc,
4880		      unsigned int fragsz, gfp_t gfp_mask)
 
4881{
4882	unsigned int size = PAGE_SIZE;
4883	struct page *page;
4884	int offset;
4885
4886	if (unlikely(!nc->va)) {
4887refill:
4888		page = __page_frag_cache_refill(nc, gfp_mask);
4889		if (!page)
4890			return NULL;
4891
4892#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4893		/* if size can vary use size else just use PAGE_SIZE */
4894		size = nc->size;
4895#endif
4896		/* Even if we own the page, we do not use atomic_set().
4897		 * This would break get_page_unless_zero() users.
4898		 */
4899		page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE);
4900
4901		/* reset page count bias and offset to start of new frag */
4902		nc->pfmemalloc = page_is_pfmemalloc(page);
4903		nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
4904		nc->offset = size;
4905	}
4906
4907	offset = nc->offset - fragsz;
4908	if (unlikely(offset < 0)) {
4909		page = virt_to_page(nc->va);
4910
4911		if (!page_ref_sub_and_test(page, nc->pagecnt_bias))
4912			goto refill;
4913
 
 
 
 
 
4914#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4915		/* if size can vary use size else just use PAGE_SIZE */
4916		size = nc->size;
4917#endif
4918		/* OK, page count is 0, we can safely set it */
4919		set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1);
4920
4921		/* reset page count bias and offset to start of new frag */
4922		nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
4923		offset = size - fragsz;
 
 
 
 
 
 
 
 
 
 
 
 
4924	}
4925
4926	nc->pagecnt_bias--;
 
4927	nc->offset = offset;
4928
4929	return nc->va + offset;
4930}
4931EXPORT_SYMBOL(page_frag_alloc);
4932
4933/*
4934 * Frees a page fragment allocated out of either a compound or order 0 page.
4935 */
4936void page_frag_free(void *addr)
4937{
4938	struct page *page = virt_to_head_page(addr);
4939
4940	if (unlikely(put_page_testzero(page)))
4941		free_the_page(page, compound_order(page));
4942}
4943EXPORT_SYMBOL(page_frag_free);
4944
4945static void *make_alloc_exact(unsigned long addr, unsigned int order,
4946		size_t size)
4947{
4948	if (addr) {
4949		unsigned long alloc_end = addr + (PAGE_SIZE << order);
4950		unsigned long used = addr + PAGE_ALIGN(size);
4951
4952		split_page(virt_to_page((void *)addr), order);
4953		while (used < alloc_end) {
4954			free_page(used);
4955			used += PAGE_SIZE;
4956		}
 
 
 
 
4957	}
4958	return (void *)addr;
4959}
4960
4961/**
4962 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
4963 * @size: the number of bytes to allocate
4964 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
4965 *
4966 * This function is similar to alloc_pages(), except that it allocates the
4967 * minimum number of pages to satisfy the request.  alloc_pages() can only
4968 * allocate memory in power-of-two pages.
4969 *
4970 * This function is also limited by MAX_ORDER.
4971 *
4972 * Memory allocated by this function must be released by free_pages_exact().
4973 *
4974 * Return: pointer to the allocated area or %NULL in case of error.
4975 */
4976void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
4977{
4978	unsigned int order = get_order(size);
4979	unsigned long addr;
4980
4981	if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
4982		gfp_mask &= ~__GFP_COMP;
4983
4984	addr = __get_free_pages(gfp_mask, order);
4985	return make_alloc_exact(addr, order, size);
4986}
4987EXPORT_SYMBOL(alloc_pages_exact);
4988
4989/**
4990 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
4991 *			   pages on a node.
4992 * @nid: the preferred node ID where memory should be allocated
4993 * @size: the number of bytes to allocate
4994 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
4995 *
4996 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
4997 * back.
4998 *
4999 * Return: pointer to the allocated area or %NULL in case of error.
5000 */
5001void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
5002{
5003	unsigned int order = get_order(size);
5004	struct page *p;
5005
5006	if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
5007		gfp_mask &= ~__GFP_COMP;
5008
5009	p = alloc_pages_node(nid, gfp_mask, order);
5010	if (!p)
5011		return NULL;
5012	return make_alloc_exact((unsigned long)page_address(p), order, size);
5013}
5014
5015/**
5016 * free_pages_exact - release memory allocated via alloc_pages_exact()
5017 * @virt: the value returned by alloc_pages_exact.
5018 * @size: size of allocation, same value as passed to alloc_pages_exact().
5019 *
5020 * Release the memory allocated by a previous call to alloc_pages_exact.
5021 */
5022void free_pages_exact(void *virt, size_t size)
5023{
5024	unsigned long addr = (unsigned long)virt;
5025	unsigned long end = addr + PAGE_ALIGN(size);
5026
5027	while (addr < end) {
5028		free_page(addr);
5029		addr += PAGE_SIZE;
5030	}
5031}
5032EXPORT_SYMBOL(free_pages_exact);
5033
5034/**
5035 * nr_free_zone_pages - count number of pages beyond high watermark
5036 * @offset: The zone index of the highest zone
5037 *
5038 * nr_free_zone_pages() counts the number of pages which are beyond the
5039 * high watermark within all zones at or below a given zone index.  For each
5040 * zone, the number of pages is calculated as:
5041 *
5042 *     nr_free_zone_pages = managed_pages - high_pages
5043 *
5044 * Return: number of pages beyond high watermark.
5045 */
5046static unsigned long nr_free_zone_pages(int offset)
5047{
5048	struct zoneref *z;
5049	struct zone *zone;
5050
5051	/* Just pick one node, since fallback list is circular */
5052	unsigned long sum = 0;
5053
5054	struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
5055
5056	for_each_zone_zonelist(zone, z, zonelist, offset) {
5057		unsigned long size = zone_managed_pages(zone);
5058		unsigned long high = high_wmark_pages(zone);
5059		if (size > high)
5060			sum += size - high;
5061	}
5062
5063	return sum;
5064}
5065
5066/**
5067 * nr_free_buffer_pages - count number of pages beyond high watermark
5068 *
5069 * nr_free_buffer_pages() counts the number of pages which are beyond the high
5070 * watermark within ZONE_DMA and ZONE_NORMAL.
5071 *
5072 * Return: number of pages beyond high watermark within ZONE_DMA and
5073 * ZONE_NORMAL.
5074 */
5075unsigned long nr_free_buffer_pages(void)
5076{
5077	return nr_free_zone_pages(gfp_zone(GFP_USER));
5078}
5079EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
5080
5081/**
5082 * nr_free_pagecache_pages - count number of pages beyond high watermark
5083 *
5084 * nr_free_pagecache_pages() counts the number of pages which are beyond the
5085 * high watermark within all zones.
5086 *
5087 * Return: number of pages beyond high watermark within all zones.
5088 */
5089unsigned long nr_free_pagecache_pages(void)
5090{
5091	return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
5092}
5093
5094static inline void show_node(struct zone *zone)
5095{
5096	if (IS_ENABLED(CONFIG_NUMA))
5097		printk("Node %d ", zone_to_nid(zone));
5098}
5099
5100long si_mem_available(void)
5101{
5102	long available;
5103	unsigned long pagecache;
5104	unsigned long wmark_low = 0;
5105	unsigned long pages[NR_LRU_LISTS];
5106	unsigned long reclaimable;
5107	struct zone *zone;
5108	int lru;
5109
5110	for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
5111		pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
5112
5113	for_each_zone(zone)
5114		wmark_low += low_wmark_pages(zone);
5115
5116	/*
5117	 * Estimate the amount of memory available for userspace allocations,
5118	 * without causing swapping.
5119	 */
5120	available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages;
5121
5122	/*
5123	 * Not all the page cache can be freed, otherwise the system will
5124	 * start swapping. Assume at least half of the page cache, or the
5125	 * low watermark worth of cache, needs to stay.
5126	 */
5127	pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
5128	pagecache -= min(pagecache / 2, wmark_low);
5129	available += pagecache;
5130
5131	/*
5132	 * Part of the reclaimable slab and other kernel memory consists of
5133	 * items that are in use, and cannot be freed. Cap this estimate at the
5134	 * low watermark.
5135	 */
5136	reclaimable = global_node_page_state(NR_SLAB_RECLAIMABLE) +
5137			global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
5138	available += reclaimable - min(reclaimable / 2, wmark_low);
5139
5140	if (available < 0)
5141		available = 0;
5142	return available;
5143}
5144EXPORT_SYMBOL_GPL(si_mem_available);
5145
5146void si_meminfo(struct sysinfo *val)
5147{
5148	val->totalram = totalram_pages();
5149	val->sharedram = global_node_page_state(NR_SHMEM);
5150	val->freeram = global_zone_page_state(NR_FREE_PAGES);
5151	val->bufferram = nr_blockdev_pages();
5152	val->totalhigh = totalhigh_pages();
5153	val->freehigh = nr_free_highpages();
5154	val->mem_unit = PAGE_SIZE;
5155}
5156
5157EXPORT_SYMBOL(si_meminfo);
5158
5159#ifdef CONFIG_NUMA
5160void si_meminfo_node(struct sysinfo *val, int nid)
5161{
5162	int zone_type;		/* needs to be signed */
5163	unsigned long managed_pages = 0;
5164	unsigned long managed_highpages = 0;
5165	unsigned long free_highpages = 0;
5166	pg_data_t *pgdat = NODE_DATA(nid);
5167
5168	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
5169		managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]);
5170	val->totalram = managed_pages;
5171	val->sharedram = node_page_state(pgdat, NR_SHMEM);
5172	val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
5173#ifdef CONFIG_HIGHMEM
5174	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
5175		struct zone *zone = &pgdat->node_zones[zone_type];
5176
5177		if (is_highmem(zone)) {
5178			managed_highpages += zone_managed_pages(zone);
5179			free_highpages += zone_page_state(zone, NR_FREE_PAGES);
5180		}
5181	}
5182	val->totalhigh = managed_highpages;
5183	val->freehigh = free_highpages;
5184#else
5185	val->totalhigh = managed_highpages;
5186	val->freehigh = free_highpages;
5187#endif
5188	val->mem_unit = PAGE_SIZE;
5189}
5190#endif
5191
5192/*
5193 * Determine whether the node should be displayed or not, depending on whether
5194 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
5195 */
5196static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask)
5197{
5198	if (!(flags & SHOW_MEM_FILTER_NODES))
5199		return false;
5200
5201	/*
5202	 * no node mask - aka implicit memory numa policy. Do not bother with
5203	 * the synchronization - read_mems_allowed_begin - because we do not
5204	 * have to be precise here.
5205	 */
5206	if (!nodemask)
5207		nodemask = &cpuset_current_mems_allowed;
5208
5209	return !node_isset(nid, *nodemask);
5210}
5211
5212#define K(x) ((x) << (PAGE_SHIFT-10))
5213
5214static void show_migration_types(unsigned char type)
5215{
5216	static const char types[MIGRATE_TYPES] = {
5217		[MIGRATE_UNMOVABLE]	= 'U',
5218		[MIGRATE_MOVABLE]	= 'M',
5219		[MIGRATE_RECLAIMABLE]	= 'E',
5220		[MIGRATE_HIGHATOMIC]	= 'H',
5221#ifdef CONFIG_CMA
5222		[MIGRATE_CMA]		= 'C',
5223#endif
5224#ifdef CONFIG_MEMORY_ISOLATION
5225		[MIGRATE_ISOLATE]	= 'I',
5226#endif
5227	};
5228	char tmp[MIGRATE_TYPES + 1];
5229	char *p = tmp;
5230	int i;
5231
5232	for (i = 0; i < MIGRATE_TYPES; i++) {
5233		if (type & (1 << i))
5234			*p++ = types[i];
5235	}
5236
5237	*p = '\0';
5238	printk(KERN_CONT "(%s) ", tmp);
5239}
5240
5241/*
5242 * Show free area list (used inside shift_scroll-lock stuff)
5243 * We also calculate the percentage fragmentation. We do this by counting the
5244 * memory on each free list with the exception of the first item on the list.
5245 *
5246 * Bits in @filter:
5247 * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
5248 *   cpuset.
5249 */
5250void show_free_areas(unsigned int filter, nodemask_t *nodemask)
5251{
5252	unsigned long free_pcp = 0;
5253	int cpu;
5254	struct zone *zone;
5255	pg_data_t *pgdat;
5256
5257	for_each_populated_zone(zone) {
5258		if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5259			continue;
5260
5261		for_each_online_cpu(cpu)
5262			free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
5263	}
5264
5265	printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
5266		" active_file:%lu inactive_file:%lu isolated_file:%lu\n"
5267		" unevictable:%lu dirty:%lu writeback:%lu unstable:%lu\n"
5268		" slab_reclaimable:%lu slab_unreclaimable:%lu\n"
5269		" mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
5270		" free:%lu free_pcp:%lu free_cma:%lu\n",
5271		global_node_page_state(NR_ACTIVE_ANON),
5272		global_node_page_state(NR_INACTIVE_ANON),
5273		global_node_page_state(NR_ISOLATED_ANON),
5274		global_node_page_state(NR_ACTIVE_FILE),
5275		global_node_page_state(NR_INACTIVE_FILE),
5276		global_node_page_state(NR_ISOLATED_FILE),
5277		global_node_page_state(NR_UNEVICTABLE),
5278		global_node_page_state(NR_FILE_DIRTY),
5279		global_node_page_state(NR_WRITEBACK),
5280		global_node_page_state(NR_UNSTABLE_NFS),
5281		global_node_page_state(NR_SLAB_RECLAIMABLE),
5282		global_node_page_state(NR_SLAB_UNRECLAIMABLE),
5283		global_node_page_state(NR_FILE_MAPPED),
5284		global_node_page_state(NR_SHMEM),
5285		global_zone_page_state(NR_PAGETABLE),
5286		global_zone_page_state(NR_BOUNCE),
5287		global_zone_page_state(NR_FREE_PAGES),
5288		free_pcp,
5289		global_zone_page_state(NR_FREE_CMA_PAGES));
5290
5291	for_each_online_pgdat(pgdat) {
5292		if (show_mem_node_skip(filter, pgdat->node_id, nodemask))
5293			continue;
5294
5295		printk("Node %d"
5296			" active_anon:%lukB"
5297			" inactive_anon:%lukB"
5298			" active_file:%lukB"
5299			" inactive_file:%lukB"
5300			" unevictable:%lukB"
5301			" isolated(anon):%lukB"
5302			" isolated(file):%lukB"
5303			" mapped:%lukB"
5304			" dirty:%lukB"
5305			" writeback:%lukB"
5306			" shmem:%lukB"
5307#ifdef CONFIG_TRANSPARENT_HUGEPAGE
5308			" shmem_thp: %lukB"
5309			" shmem_pmdmapped: %lukB"
5310			" anon_thp: %lukB"
5311#endif
5312			" writeback_tmp:%lukB"
5313			" unstable:%lukB"
5314			" all_unreclaimable? %s"
5315			"\n",
5316			pgdat->node_id,
5317			K(node_page_state(pgdat, NR_ACTIVE_ANON)),
5318			K(node_page_state(pgdat, NR_INACTIVE_ANON)),
5319			K(node_page_state(pgdat, NR_ACTIVE_FILE)),
5320			K(node_page_state(pgdat, NR_INACTIVE_FILE)),
5321			K(node_page_state(pgdat, NR_UNEVICTABLE)),
5322			K(node_page_state(pgdat, NR_ISOLATED_ANON)),
5323			K(node_page_state(pgdat, NR_ISOLATED_FILE)),
5324			K(node_page_state(pgdat, NR_FILE_MAPPED)),
5325			K(node_page_state(pgdat, NR_FILE_DIRTY)),
5326			K(node_page_state(pgdat, NR_WRITEBACK)),
5327			K(node_page_state(pgdat, NR_SHMEM)),
5328#ifdef CONFIG_TRANSPARENT_HUGEPAGE
5329			K(node_page_state(pgdat, NR_SHMEM_THPS) * HPAGE_PMD_NR),
5330			K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)
5331					* HPAGE_PMD_NR),
5332			K(node_page_state(pgdat, NR_ANON_THPS) * HPAGE_PMD_NR),
5333#endif
5334			K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
5335			K(node_page_state(pgdat, NR_UNSTABLE_NFS)),
5336			pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ?
5337				"yes" : "no");
5338	}
5339
5340	for_each_populated_zone(zone) {
5341		int i;
5342
5343		if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5344			continue;
5345
5346		free_pcp = 0;
5347		for_each_online_cpu(cpu)
5348			free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
5349
5350		show_node(zone);
5351		printk(KERN_CONT
5352			"%s"
5353			" free:%lukB"
5354			" min:%lukB"
5355			" low:%lukB"
5356			" high:%lukB"
5357			" active_anon:%lukB"
5358			" inactive_anon:%lukB"
5359			" active_file:%lukB"
5360			" inactive_file:%lukB"
5361			" unevictable:%lukB"
5362			" writepending:%lukB"
5363			" present:%lukB"
5364			" managed:%lukB"
5365			" mlocked:%lukB"
5366			" kernel_stack:%lukB"
5367			" pagetables:%lukB"
5368			" bounce:%lukB"
5369			" free_pcp:%lukB"
5370			" local_pcp:%ukB"
5371			" free_cma:%lukB"
5372			"\n",
5373			zone->name,
5374			K(zone_page_state(zone, NR_FREE_PAGES)),
5375			K(min_wmark_pages(zone)),
5376			K(low_wmark_pages(zone)),
5377			K(high_wmark_pages(zone)),
5378			K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)),
5379			K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)),
5380			K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
5381			K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
5382			K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
5383			K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
5384			K(zone->present_pages),
5385			K(zone_managed_pages(zone)),
5386			K(zone_page_state(zone, NR_MLOCK)),
5387			zone_page_state(zone, NR_KERNEL_STACK_KB),
5388			K(zone_page_state(zone, NR_PAGETABLE)),
5389			K(zone_page_state(zone, NR_BOUNCE)),
5390			K(free_pcp),
5391			K(this_cpu_read(zone->pageset->pcp.count)),
5392			K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
5393		printk("lowmem_reserve[]:");
5394		for (i = 0; i < MAX_NR_ZONES; i++)
5395			printk(KERN_CONT " %ld", zone->lowmem_reserve[i]);
5396		printk(KERN_CONT "\n");
5397	}
5398
5399	for_each_populated_zone(zone) {
5400		unsigned int order;
5401		unsigned long nr[MAX_ORDER], flags, total = 0;
5402		unsigned char types[MAX_ORDER];
5403
5404		if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5405			continue;
5406		show_node(zone);
5407		printk(KERN_CONT "%s: ", zone->name);
5408
5409		spin_lock_irqsave(&zone->lock, flags);
5410		for (order = 0; order < MAX_ORDER; order++) {
5411			struct free_area *area = &zone->free_area[order];
5412			int type;
5413
5414			nr[order] = area->nr_free;
5415			total += nr[order] << order;
5416
5417			types[order] = 0;
5418			for (type = 0; type < MIGRATE_TYPES; type++) {
5419				if (!free_area_empty(area, type))
5420					types[order] |= 1 << type;
5421			}
5422		}
5423		spin_unlock_irqrestore(&zone->lock, flags);
5424		for (order = 0; order < MAX_ORDER; order++) {
5425			printk(KERN_CONT "%lu*%lukB ",
5426			       nr[order], K(1UL) << order);
5427			if (nr[order])
5428				show_migration_types(types[order]);
5429		}
5430		printk(KERN_CONT "= %lukB\n", K(total));
5431	}
5432
5433	hugetlb_show_meminfo();
5434
5435	printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
5436
5437	show_swap_cache_info();
5438}
5439
5440static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
5441{
5442	zoneref->zone = zone;
5443	zoneref->zone_idx = zone_idx(zone);
5444}
5445
5446/*
5447 * Builds allocation fallback zone lists.
5448 *
5449 * Add all populated zones of a node to the zonelist.
5450 */
5451static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs)
5452{
5453	struct zone *zone;
5454	enum zone_type zone_type = MAX_NR_ZONES;
5455	int nr_zones = 0;
5456
5457	do {
5458		zone_type--;
5459		zone = pgdat->node_zones + zone_type;
5460		if (managed_zone(zone)) {
5461			zoneref_set_zone(zone, &zonerefs[nr_zones++]);
5462			check_highest_zone(zone_type);
5463		}
5464	} while (zone_type);
5465
5466	return nr_zones;
5467}
5468
5469#ifdef CONFIG_NUMA
5470
5471static int __parse_numa_zonelist_order(char *s)
5472{
5473	/*
5474	 * We used to support different zonlists modes but they turned
5475	 * out to be just not useful. Let's keep the warning in place
5476	 * if somebody still use the cmd line parameter so that we do
5477	 * not fail it silently
5478	 */
5479	if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) {
5480		pr_warn("Ignoring unsupported numa_zonelist_order value:  %s\n", s);
5481		return -EINVAL;
5482	}
5483	return 0;
5484}
5485
5486static __init int setup_numa_zonelist_order(char *s)
5487{
5488	if (!s)
5489		return 0;
5490
5491	return __parse_numa_zonelist_order(s);
5492}
5493early_param("numa_zonelist_order", setup_numa_zonelist_order);
5494
5495char numa_zonelist_order[] = "Node";
5496
5497/*
5498 * sysctl handler for numa_zonelist_order
5499 */
5500int numa_zonelist_order_handler(struct ctl_table *table, int write,
5501		void __user *buffer, size_t *length,
5502		loff_t *ppos)
5503{
5504	char *str;
5505	int ret;
5506
5507	if (!write)
5508		return proc_dostring(table, write, buffer, length, ppos);
5509	str = memdup_user_nul(buffer, 16);
5510	if (IS_ERR(str))
5511		return PTR_ERR(str);
5512
5513	ret = __parse_numa_zonelist_order(str);
5514	kfree(str);
5515	return ret;
5516}
5517
5518
5519#define MAX_NODE_LOAD (nr_online_nodes)
5520static int node_load[MAX_NUMNODES];
5521
5522/**
5523 * find_next_best_node - find the next node that should appear in a given node's fallback list
5524 * @node: node whose fallback list we're appending
5525 * @used_node_mask: nodemask_t of already used nodes
5526 *
5527 * We use a number of factors to determine which is the next node that should
5528 * appear on a given node's fallback list.  The node should not have appeared
5529 * already in @node's fallback list, and it should be the next closest node
5530 * according to the distance array (which contains arbitrary distance values
5531 * from each node to each node in the system), and should also prefer nodes
5532 * with no CPUs, since presumably they'll have very little allocation pressure
5533 * on them otherwise.
5534 *
5535 * Return: node id of the found node or %NUMA_NO_NODE if no node is found.
5536 */
5537static int find_next_best_node(int node, nodemask_t *used_node_mask)
5538{
5539	int n, val;
5540	int min_val = INT_MAX;
5541	int best_node = NUMA_NO_NODE;
5542	const struct cpumask *tmp = cpumask_of_node(0);
5543
5544	/* Use the local node if we haven't already */
5545	if (!node_isset(node, *used_node_mask)) {
 
 
 
5546		node_set(node, *used_node_mask);
5547		return node;
5548	}
5549
5550	for_each_node_state(n, N_MEMORY) {
5551
5552		/* Don't want a node to appear more than once */
5553		if (node_isset(n, *used_node_mask))
5554			continue;
5555
5556		/* Use the distance array to find the distance */
5557		val = node_distance(node, n);
5558
5559		/* Penalize nodes under us ("prefer the next node") */
5560		val += (n < node);
5561
5562		/* Give preference to headless and unused nodes */
5563		tmp = cpumask_of_node(n);
5564		if (!cpumask_empty(tmp))
5565			val += PENALTY_FOR_NODE_WITH_CPUS;
5566
5567		/* Slight preference for less loaded node */
5568		val *= (MAX_NODE_LOAD*MAX_NUMNODES);
5569		val += node_load[n];
5570
5571		if (val < min_val) {
5572			min_val = val;
5573			best_node = n;
5574		}
5575	}
5576
5577	if (best_node >= 0)
5578		node_set(best_node, *used_node_mask);
5579
5580	return best_node;
5581}
5582
5583
5584/*
5585 * Build zonelists ordered by node and zones within node.
5586 * This results in maximum locality--normal zone overflows into local
5587 * DMA zone, if any--but risks exhausting DMA zone.
5588 */
5589static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order,
5590		unsigned nr_nodes)
5591{
5592	struct zoneref *zonerefs;
5593	int i;
5594
5595	zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
5596
5597	for (i = 0; i < nr_nodes; i++) {
5598		int nr_zones;
5599
5600		pg_data_t *node = NODE_DATA(node_order[i]);
5601
5602		nr_zones = build_zonerefs_node(node, zonerefs);
5603		zonerefs += nr_zones;
5604	}
5605	zonerefs->zone = NULL;
5606	zonerefs->zone_idx = 0;
5607}
5608
5609/*
5610 * Build gfp_thisnode zonelists
5611 */
5612static void build_thisnode_zonelists(pg_data_t *pgdat)
5613{
5614	struct zoneref *zonerefs;
5615	int nr_zones;
5616
5617	zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs;
5618	nr_zones = build_zonerefs_node(pgdat, zonerefs);
5619	zonerefs += nr_zones;
5620	zonerefs->zone = NULL;
5621	zonerefs->zone_idx = 0;
5622}
5623
5624/*
5625 * Build zonelists ordered by zone and nodes within zones.
5626 * This results in conserving DMA zone[s] until all Normal memory is
5627 * exhausted, but results in overflowing to remote node while memory
5628 * may still exist in local DMA zone.
5629 */
5630
5631static void build_zonelists(pg_data_t *pgdat)
5632{
5633	static int node_order[MAX_NUMNODES];
5634	int node, load, nr_nodes = 0;
5635	nodemask_t used_mask;
5636	int local_node, prev_node;
5637
5638	/* NUMA-aware ordering of nodes */
5639	local_node = pgdat->node_id;
5640	load = nr_online_nodes;
5641	prev_node = local_node;
5642	nodes_clear(used_mask);
5643
5644	memset(node_order, 0, sizeof(node_order));
5645	while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
5646		/*
5647		 * We don't want to pressure a particular node.
5648		 * So adding penalty to the first node in same
5649		 * distance group to make it round-robin.
5650		 */
5651		if (node_distance(local_node, node) !=
5652		    node_distance(local_node, prev_node))
5653			node_load[node] = load;
5654
5655		node_order[nr_nodes++] = node;
5656		prev_node = node;
5657		load--;
5658	}
5659
5660	build_zonelists_in_node_order(pgdat, node_order, nr_nodes);
5661	build_thisnode_zonelists(pgdat);
 
 
 
 
5662}
5663
5664#ifdef CONFIG_HAVE_MEMORYLESS_NODES
5665/*
5666 * Return node id of node used for "local" allocations.
5667 * I.e., first node id of first zone in arg node's generic zonelist.
5668 * Used for initializing percpu 'numa_mem', which is used primarily
5669 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
5670 */
5671int local_memory_node(int node)
5672{
5673	struct zoneref *z;
5674
5675	z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
5676				   gfp_zone(GFP_KERNEL),
5677				   NULL);
5678	return zone_to_nid(z->zone);
5679}
5680#endif
5681
5682static void setup_min_unmapped_ratio(void);
5683static void setup_min_slab_ratio(void);
5684#else	/* CONFIG_NUMA */
5685
5686static void build_zonelists(pg_data_t *pgdat)
5687{
5688	int node, local_node;
5689	struct zoneref *zonerefs;
5690	int nr_zones;
5691
5692	local_node = pgdat->node_id;
5693
5694	zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
5695	nr_zones = build_zonerefs_node(pgdat, zonerefs);
5696	zonerefs += nr_zones;
5697
5698	/*
5699	 * Now we build the zonelist so that it contains the zones
5700	 * of all the other nodes.
5701	 * We don't want to pressure a particular node, so when
5702	 * building the zones for node N, we make sure that the
5703	 * zones coming right after the local ones are those from
5704	 * node N+1 (modulo N)
5705	 */
5706	for (node = local_node + 1; node < MAX_NUMNODES; node++) {
5707		if (!node_online(node))
5708			continue;
5709		nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
5710		zonerefs += nr_zones;
5711	}
5712	for (node = 0; node < local_node; node++) {
5713		if (!node_online(node))
5714			continue;
5715		nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
5716		zonerefs += nr_zones;
5717	}
5718
5719	zonerefs->zone = NULL;
5720	zonerefs->zone_idx = 0;
5721}
5722
5723#endif	/* CONFIG_NUMA */
5724
5725/*
5726 * Boot pageset table. One per cpu which is going to be used for all
5727 * zones and all nodes. The parameters will be set in such a way
5728 * that an item put on a list will immediately be handed over to
5729 * the buddy list. This is safe since pageset manipulation is done
5730 * with interrupts disabled.
5731 *
5732 * The boot_pagesets must be kept even after bootup is complete for
5733 * unused processors and/or zones. They do play a role for bootstrapping
5734 * hotplugged processors.
5735 *
5736 * zoneinfo_show() and maybe other functions do
5737 * not check if the processor is online before following the pageset pointer.
5738 * Other parts of the kernel may not check if the zone is available.
5739 */
5740static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
5741static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
5742static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
 
 
 
5743
5744static void __build_all_zonelists(void *data)
5745{
5746	int nid;
5747	int __maybe_unused cpu;
5748	pg_data_t *self = data;
5749	static DEFINE_SPINLOCK(lock);
5750
5751	spin_lock(&lock);
 
 
 
 
 
 
 
 
 
 
 
5752
5753#ifdef CONFIG_NUMA
5754	memset(node_load, 0, sizeof(node_load));
5755#endif
5756
5757	/*
5758	 * This node is hotadded and no memory is yet present.   So just
5759	 * building zonelists is fine - no need to touch other nodes.
5760	 */
5761	if (self && !node_online(self->node_id)) {
5762		build_zonelists(self);
5763	} else {
5764		for_each_online_node(nid) {
 
 
 
 
5765			pg_data_t *pgdat = NODE_DATA(nid);
5766
5767			build_zonelists(pgdat);
5768		}
5769
5770#ifdef CONFIG_HAVE_MEMORYLESS_NODES
5771		/*
5772		 * We now know the "local memory node" for each node--
5773		 * i.e., the node of the first zone in the generic zonelist.
5774		 * Set up numa_mem percpu variable for on-line cpus.  During
5775		 * boot, only the boot cpu should be on-line;  we'll init the
5776		 * secondary cpus' numa_mem as they come on-line.  During
5777		 * node/memory hotplug, we'll fixup all on-line cpus.
5778		 */
5779		for_each_online_cpu(cpu)
5780			set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
5781#endif
5782	}
5783
5784	spin_unlock(&lock);
 
5785}
5786
5787static noinline void __init
5788build_all_zonelists_init(void)
5789{
5790	int cpu;
5791
5792	__build_all_zonelists(NULL);
5793
5794	/*
5795	 * Initialize the boot_pagesets that are going to be used
5796	 * for bootstrapping processors. The real pagesets for
5797	 * each zone will be allocated later when the per cpu
5798	 * allocator is available.
5799	 *
5800	 * boot_pagesets are used also for bootstrapping offline
5801	 * cpus if the system is already booted because the pagesets
5802	 * are needed to initialize allocators on a specific cpu too.
5803	 * F.e. the percpu allocator needs the page allocator which
5804	 * needs the percpu allocator in order to allocate its pagesets
5805	 * (a chicken-egg dilemma).
5806	 */
5807	for_each_possible_cpu(cpu)
5808		setup_pageset(&per_cpu(boot_pageset, cpu), 0);
5809
5810	mminit_verify_zonelist();
5811	cpuset_init_current_mems_allowed();
5812}
5813
5814/*
5815 * unless system_state == SYSTEM_BOOTING.
5816 *
5817 * __ref due to call of __init annotated helper build_all_zonelists_init
5818 * [protected by SYSTEM_BOOTING].
5819 */
5820void __ref build_all_zonelists(pg_data_t *pgdat)
5821{
 
 
5822	if (system_state == SYSTEM_BOOTING) {
5823		build_all_zonelists_init();
5824	} else {
5825		__build_all_zonelists(pgdat);
5826		/* cpuset refresh routine should be here */
5827	}
5828	vm_total_pages = nr_free_pagecache_pages();
 
5829	/*
5830	 * Disable grouping by mobility if the number of pages in the
5831	 * system is too low to allow the mechanism to work. It would be
5832	 * more accurate, but expensive to check per-zone. This check is
5833	 * made on memory-hotadd so a system can start with mobility
5834	 * disabled and enable it later
5835	 */
5836	if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
5837		page_group_by_mobility_disabled = 1;
5838	else
5839		page_group_by_mobility_disabled = 0;
5840
5841	pr_info("Built %u zonelists, mobility grouping %s.  Total pages: %ld\n",
5842		nr_online_nodes,
5843		page_group_by_mobility_disabled ? "off" : "on",
5844		vm_total_pages);
5845#ifdef CONFIG_NUMA
5846	pr_info("Policy zone: %s\n", zone_names[policy_zone]);
5847#endif
5848}
5849
5850/* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
5851static bool __meminit
5852overlap_memmap_init(unsigned long zone, unsigned long *pfn)
5853{
5854#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5855	static struct memblock_region *r;
5856
5857	if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
5858		if (!r || *pfn >= memblock_region_memory_end_pfn(r)) {
5859			for_each_memblock(memory, r) {
5860				if (*pfn < memblock_region_memory_end_pfn(r))
5861					break;
5862			}
5863		}
5864		if (*pfn >= memblock_region_memory_base_pfn(r) &&
5865		    memblock_is_mirror(r)) {
5866			*pfn = memblock_region_memory_end_pfn(r);
5867			return true;
5868		}
5869	}
5870#endif
5871	return false;
5872}
5873
5874/*
5875 * Initially all pages are reserved - free ones are freed
5876 * up by memblock_free_all() once the early boot process is
5877 * done. Non-atomic initialization, single-pass.
5878 */
5879void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
5880		unsigned long start_pfn, enum memmap_context context,
5881		struct vmem_altmap *altmap)
5882{
5883	unsigned long pfn, end_pfn = start_pfn + size;
5884	struct page *page;
5885
5886	if (highest_memmap_pfn < end_pfn - 1)
5887		highest_memmap_pfn = end_pfn - 1;
5888
5889#ifdef CONFIG_ZONE_DEVICE
5890	/*
5891	 * Honor reservation requested by the driver for this ZONE_DEVICE
5892	 * memory. We limit the total number of pages to initialize to just
5893	 * those that might contain the memory mapping. We will defer the
5894	 * ZONE_DEVICE page initialization until after we have released
5895	 * the hotplug lock.
5896	 */
5897	if (zone == ZONE_DEVICE) {
5898		if (!altmap)
5899			return;
5900
5901		if (start_pfn == altmap->base_pfn)
5902			start_pfn += altmap->reserve;
5903		end_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
5904	}
5905#endif
5906
5907	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
5908		/*
5909		 * There can be holes in boot-time mem_map[]s handed to this
5910		 * function.  They do not exist on hotplugged memory.
5911		 */
5912		if (context == MEMMAP_EARLY) {
5913			if (!early_pfn_valid(pfn))
5914				continue;
5915			if (!early_pfn_in_nid(pfn, nid))
5916				continue;
5917			if (overlap_memmap_init(zone, &pfn))
5918				continue;
5919			if (defer_init(nid, pfn, end_pfn))
5920				break;
5921		}
5922
5923		page = pfn_to_page(pfn);
5924		__init_single_page(page, pfn, zone, nid);
5925		if (context == MEMMAP_HOTPLUG)
5926			__SetPageReserved(page);
5927
5928		/*
5929		 * Mark the block movable so that blocks are reserved for
5930		 * movable at startup. This will force kernel allocations
5931		 * to reserve their blocks rather than leaking throughout
5932		 * the address space during boot when many long-lived
5933		 * kernel allocations are made.
5934		 *
5935		 * bitmap is created for zone's valid pfn range. but memmap
5936		 * can be created for invalid pages (for alignment)
5937		 * check here not to call set_pageblock_migratetype() against
5938		 * pfn out of zone.
5939		 */
5940		if (!(pfn & (pageblock_nr_pages - 1))) {
5941			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5942			cond_resched();
5943		}
5944	}
5945}
5946
5947#ifdef CONFIG_ZONE_DEVICE
5948void __ref memmap_init_zone_device(struct zone *zone,
5949				   unsigned long start_pfn,
5950				   unsigned long size,
5951				   struct dev_pagemap *pgmap)
5952{
5953	unsigned long pfn, end_pfn = start_pfn + size;
5954	struct pglist_data *pgdat = zone->zone_pgdat;
5955	struct vmem_altmap *altmap = pgmap_altmap(pgmap);
5956	unsigned long zone_idx = zone_idx(zone);
5957	unsigned long start = jiffies;
5958	int nid = pgdat->node_id;
5959
5960	if (WARN_ON_ONCE(!pgmap || zone_idx(zone) != ZONE_DEVICE))
5961		return;
5962
5963	/*
5964	 * The call to memmap_init_zone should have already taken care
5965	 * of the pages reserved for the memmap, so we can just jump to
5966	 * the end of that region and start processing the device pages.
5967	 */
5968	if (altmap) {
5969		start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
5970		size = end_pfn - start_pfn;
5971	}
5972
5973	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
5974		struct page *page = pfn_to_page(pfn);
5975
5976		__init_single_page(page, pfn, zone_idx, nid);
5977
5978		/*
5979		 * Mark page reserved as it will need to wait for onlining
5980		 * phase for it to be fully associated with a zone.
5981		 *
5982		 * We can use the non-atomic __set_bit operation for setting
5983		 * the flag as we are still initializing the pages.
5984		 */
5985		__SetPageReserved(page);
5986
5987		/*
5988		 * ZONE_DEVICE pages union ->lru with a ->pgmap back pointer
5989		 * and zone_device_data.  It is a bug if a ZONE_DEVICE page is
5990		 * ever freed or placed on a driver-private list.
5991		 */
5992		page->pgmap = pgmap;
5993		page->zone_device_data = NULL;
5994
5995		/*
5996		 * Mark the block movable so that blocks are reserved for
5997		 * movable at startup. This will force kernel allocations
5998		 * to reserve their blocks rather than leaking throughout
5999		 * the address space during boot when many long-lived
6000		 * kernel allocations are made.
6001		 *
6002		 * bitmap is created for zone's valid pfn range. but memmap
6003		 * can be created for invalid pages (for alignment)
6004		 * check here not to call set_pageblock_migratetype() against
6005		 * pfn out of zone.
6006		 *
6007		 * Please note that MEMMAP_HOTPLUG path doesn't clear memmap
6008		 * because this is done early in section_activate()
6009		 */
6010		if (!(pfn & (pageblock_nr_pages - 1))) {
6011			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
6012			cond_resched();
6013		}
6014	}
6015
6016	pr_info("%s initialised %lu pages in %ums\n", __func__,
6017		size, jiffies_to_msecs(jiffies - start));
6018}
6019
6020#endif
6021static void __meminit zone_init_free_lists(struct zone *zone)
6022{
6023	unsigned int order, t;
6024	for_each_migratetype_order(order, t) {
6025		INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
6026		zone->free_area[order].nr_free = 0;
6027	}
6028}
6029
6030void __meminit __weak memmap_init(unsigned long size, int nid,
6031				  unsigned long zone, unsigned long start_pfn)
6032{
6033	memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL);
6034}
6035
6036static int zone_batchsize(struct zone *zone)
6037{
6038#ifdef CONFIG_MMU
6039	int batch;
6040
6041	/*
6042	 * The per-cpu-pages pools are set to around 1000th of the
6043	 * size of the zone.
 
 
6044	 */
6045	batch = zone_managed_pages(zone) / 1024;
6046	/* But no more than a meg. */
6047	if (batch * PAGE_SIZE > 1024 * 1024)
6048		batch = (1024 * 1024) / PAGE_SIZE;
6049	batch /= 4;		/* We effectively *= 4 below */
6050	if (batch < 1)
6051		batch = 1;
6052
6053	/*
6054	 * Clamp the batch to a 2^n - 1 value. Having a power
6055	 * of 2 value was found to be more likely to have
6056	 * suboptimal cache aliasing properties in some cases.
6057	 *
6058	 * For example if 2 tasks are alternately allocating
6059	 * batches of pages, one task can end up with a lot
6060	 * of pages of one half of the possible page colors
6061	 * and the other with pages of the other colors.
6062	 */
6063	batch = rounddown_pow_of_two(batch + batch/2) - 1;
6064
6065	return batch;
6066
6067#else
6068	/* The deferral and batching of frees should be suppressed under NOMMU
6069	 * conditions.
6070	 *
6071	 * The problem is that NOMMU needs to be able to allocate large chunks
6072	 * of contiguous memory as there's no hardware page translation to
6073	 * assemble apparent contiguous memory from discontiguous pages.
6074	 *
6075	 * Queueing large contiguous runs of pages for batching, however,
6076	 * causes the pages to actually be freed in smaller chunks.  As there
6077	 * can be a significant delay between the individual batches being
6078	 * recycled, this leads to the once large chunks of space being
6079	 * fragmented and becoming unavailable for high-order allocations.
6080	 */
6081	return 0;
6082#endif
6083}
6084
6085/*
6086 * pcp->high and pcp->batch values are related and dependent on one another:
6087 * ->batch must never be higher then ->high.
6088 * The following function updates them in a safe manner without read side
6089 * locking.
6090 *
6091 * Any new users of pcp->batch and pcp->high should ensure they can cope with
6092 * those fields changing asynchronously (acording the the above rule).
6093 *
6094 * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
6095 * outside of boot time (or some other assurance that no concurrent updaters
6096 * exist).
6097 */
6098static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
6099		unsigned long batch)
6100{
6101       /* start with a fail safe value for batch */
6102	pcp->batch = 1;
6103	smp_wmb();
6104
6105       /* Update high, then batch, in order */
6106	pcp->high = high;
6107	smp_wmb();
6108
6109	pcp->batch = batch;
6110}
6111
6112/* a companion to pageset_set_high() */
6113static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
6114{
6115	pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
6116}
6117
6118static void pageset_init(struct per_cpu_pageset *p)
6119{
6120	struct per_cpu_pages *pcp;
6121	int migratetype;
6122
6123	memset(p, 0, sizeof(*p));
6124
6125	pcp = &p->pcp;
6126	for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
6127		INIT_LIST_HEAD(&pcp->lists[migratetype]);
6128}
6129
6130static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
6131{
6132	pageset_init(p);
6133	pageset_set_batch(p, batch);
6134}
6135
6136/*
6137 * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
6138 * to the value high for the pageset p.
6139 */
6140static void pageset_set_high(struct per_cpu_pageset *p,
6141				unsigned long high)
6142{
6143	unsigned long batch = max(1UL, high / 4);
6144	if ((high / 4) > (PAGE_SHIFT * 8))
6145		batch = PAGE_SHIFT * 8;
6146
6147	pageset_update(&p->pcp, high, batch);
6148}
6149
6150static void pageset_set_high_and_batch(struct zone *zone,
6151				       struct per_cpu_pageset *pcp)
6152{
6153	if (percpu_pagelist_fraction)
6154		pageset_set_high(pcp,
6155			(zone_managed_pages(zone) /
6156				percpu_pagelist_fraction));
6157	else
6158		pageset_set_batch(pcp, zone_batchsize(zone));
6159}
6160
6161static void __meminit zone_pageset_init(struct zone *zone, int cpu)
6162{
6163	struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
6164
6165	pageset_init(pcp);
6166	pageset_set_high_and_batch(zone, pcp);
6167}
6168
6169void __meminit setup_zone_pageset(struct zone *zone)
6170{
6171	int cpu;
6172	zone->pageset = alloc_percpu(struct per_cpu_pageset);
6173	for_each_possible_cpu(cpu)
6174		zone_pageset_init(zone, cpu);
6175}
6176
6177/*
6178 * Allocate per cpu pagesets and initialize them.
6179 * Before this call only boot pagesets were available.
6180 */
6181void __init setup_per_cpu_pageset(void)
6182{
6183	struct pglist_data *pgdat;
6184	struct zone *zone;
6185
6186	for_each_populated_zone(zone)
6187		setup_zone_pageset(zone);
6188
6189	for_each_online_pgdat(pgdat)
6190		pgdat->per_cpu_nodestats =
6191			alloc_percpu(struct per_cpu_nodestat);
6192}
 
 
 
 
 
 
 
 
 
 
 
6193
6194static __meminit void zone_pcp_init(struct zone *zone)
6195{
6196	/*
6197	 * per cpu subsystem is not up at this point. The following code
6198	 * relies on the ability of the linker to provide the
6199	 * offset of a (static) per cpu variable into the per cpu area.
 
 
 
6200	 */
6201	zone->pageset = &boot_pageset;
6202
6203	if (populated_zone(zone))
6204		printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%u\n",
6205			zone->name, zone->present_pages,
6206					 zone_batchsize(zone));
6207}
6208
6209void __meminit init_currently_empty_zone(struct zone *zone,
6210					unsigned long zone_start_pfn,
6211					unsigned long size)
6212{
6213	struct pglist_data *pgdat = zone->zone_pgdat;
6214	int zone_idx = zone_idx(zone) + 1;
6215
6216	if (zone_idx > pgdat->nr_zones)
6217		pgdat->nr_zones = zone_idx;
6218
6219	zone->zone_start_pfn = zone_start_pfn;
6220
6221	mminit_dprintk(MMINIT_TRACE, "memmap_init",
6222			"Initialising map node %d zone %lu pfns %lu -> %lu\n",
6223			pgdat->node_id,
6224			(unsigned long)zone_idx(zone),
6225			zone_start_pfn, (zone_start_pfn + size));
6226
6227	zone_init_free_lists(zone);
6228	zone->initialized = 1;
6229}
6230
6231#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
6232#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
6233
6234/*
6235 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
6236 */
6237int __meminit __early_pfn_to_nid(unsigned long pfn,
6238					struct mminit_pfnnid_cache *state)
6239{
6240	unsigned long start_pfn, end_pfn;
6241	int nid;
6242
6243	if (state->last_start <= pfn && pfn < state->last_end)
6244		return state->last_nid;
6245
6246	nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
6247	if (nid != NUMA_NO_NODE) {
6248		state->last_start = start_pfn;
6249		state->last_end = end_pfn;
6250		state->last_nid = nid;
6251	}
6252
6253	return nid;
6254}
6255#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
6256
6257/**
6258 * free_bootmem_with_active_regions - Call memblock_free_early_nid for each active range
6259 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
6260 * @max_low_pfn: The highest PFN that will be passed to memblock_free_early_nid
6261 *
6262 * If an architecture guarantees that all ranges registered contain no holes
6263 * and may be freed, this this function may be used instead of calling
6264 * memblock_free_early_nid() manually.
6265 */
6266void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
6267{
6268	unsigned long start_pfn, end_pfn;
6269	int i, this_nid;
6270
6271	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
6272		start_pfn = min(start_pfn, max_low_pfn);
6273		end_pfn = min(end_pfn, max_low_pfn);
6274
6275		if (start_pfn < end_pfn)
6276			memblock_free_early_nid(PFN_PHYS(start_pfn),
6277					(end_pfn - start_pfn) << PAGE_SHIFT,
6278					this_nid);
6279	}
6280}
6281
6282/**
6283 * sparse_memory_present_with_active_regions - Call memory_present for each active range
6284 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
6285 *
6286 * If an architecture guarantees that all ranges registered contain no holes and may
6287 * be freed, this function may be used instead of calling memory_present() manually.
6288 */
6289void __init sparse_memory_present_with_active_regions(int nid)
6290{
6291	unsigned long start_pfn, end_pfn;
6292	int i, this_nid;
6293
6294	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
6295		memory_present(this_nid, start_pfn, end_pfn);
6296}
6297
6298/**
6299 * get_pfn_range_for_nid - Return the start and end page frames for a node
6300 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
6301 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
6302 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
6303 *
6304 * It returns the start and end page frame of a node based on information
6305 * provided by memblock_set_node(). If called for a node
6306 * with no available memory, a warning is printed and the start and end
6307 * PFNs will be 0.
6308 */
6309void __init get_pfn_range_for_nid(unsigned int nid,
6310			unsigned long *start_pfn, unsigned long *end_pfn)
6311{
6312	unsigned long this_start_pfn, this_end_pfn;
6313	int i;
6314
6315	*start_pfn = -1UL;
6316	*end_pfn = 0;
6317
6318	for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
6319		*start_pfn = min(*start_pfn, this_start_pfn);
6320		*end_pfn = max(*end_pfn, this_end_pfn);
6321	}
6322
6323	if (*start_pfn == -1UL)
6324		*start_pfn = 0;
6325}
6326
6327/*
6328 * This finds a zone that can be used for ZONE_MOVABLE pages. The
6329 * assumption is made that zones within a node are ordered in monotonic
6330 * increasing memory addresses so that the "highest" populated zone is used
6331 */
6332static void __init find_usable_zone_for_movable(void)
6333{
6334	int zone_index;
6335	for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
6336		if (zone_index == ZONE_MOVABLE)
6337			continue;
6338
6339		if (arch_zone_highest_possible_pfn[zone_index] >
6340				arch_zone_lowest_possible_pfn[zone_index])
6341			break;
6342	}
6343
6344	VM_BUG_ON(zone_index == -1);
6345	movable_zone = zone_index;
6346}
6347
6348/*
6349 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
6350 * because it is sized independent of architecture. Unlike the other zones,
6351 * the starting point for ZONE_MOVABLE is not fixed. It may be different
6352 * in each node depending on the size of each node and how evenly kernelcore
6353 * is distributed. This helper function adjusts the zone ranges
6354 * provided by the architecture for a given node by using the end of the
6355 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
6356 * zones within a node are in order of monotonic increases memory addresses
6357 */
6358static void __init adjust_zone_range_for_zone_movable(int nid,
6359					unsigned long zone_type,
6360					unsigned long node_start_pfn,
6361					unsigned long node_end_pfn,
6362					unsigned long *zone_start_pfn,
6363					unsigned long *zone_end_pfn)
6364{
6365	/* Only adjust if ZONE_MOVABLE is on this node */
6366	if (zone_movable_pfn[nid]) {
6367		/* Size ZONE_MOVABLE */
6368		if (zone_type == ZONE_MOVABLE) {
6369			*zone_start_pfn = zone_movable_pfn[nid];
6370			*zone_end_pfn = min(node_end_pfn,
6371				arch_zone_highest_possible_pfn[movable_zone]);
6372
6373		/* Adjust for ZONE_MOVABLE starting within this range */
6374		} else if (!mirrored_kernelcore &&
6375			*zone_start_pfn < zone_movable_pfn[nid] &&
6376			*zone_end_pfn > zone_movable_pfn[nid]) {
6377			*zone_end_pfn = zone_movable_pfn[nid];
6378
6379		/* Check if this whole range is within ZONE_MOVABLE */
6380		} else if (*zone_start_pfn >= zone_movable_pfn[nid])
6381			*zone_start_pfn = *zone_end_pfn;
6382	}
6383}
6384
6385/*
6386 * Return the number of pages a zone spans in a node, including holes
6387 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
6388 */
6389static unsigned long __init zone_spanned_pages_in_node(int nid,
6390					unsigned long zone_type,
6391					unsigned long node_start_pfn,
6392					unsigned long node_end_pfn,
6393					unsigned long *zone_start_pfn,
6394					unsigned long *zone_end_pfn,
6395					unsigned long *ignored)
6396{
6397	unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
6398	unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
6399	/* When hotadd a new node from cpu_up(), the node should be empty */
6400	if (!node_start_pfn && !node_end_pfn)
6401		return 0;
6402
6403	/* Get the start and end of the zone */
6404	*zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
6405	*zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
6406	adjust_zone_range_for_zone_movable(nid, zone_type,
6407				node_start_pfn, node_end_pfn,
6408				zone_start_pfn, zone_end_pfn);
6409
6410	/* Check that this node has pages within the zone's required range */
6411	if (*zone_end_pfn < node_start_pfn || *zone_start_pfn > node_end_pfn)
6412		return 0;
6413
6414	/* Move the zone boundaries inside the node if necessary */
6415	*zone_end_pfn = min(*zone_end_pfn, node_end_pfn);
6416	*zone_start_pfn = max(*zone_start_pfn, node_start_pfn);
6417
6418	/* Return the spanned pages */
6419	return *zone_end_pfn - *zone_start_pfn;
6420}
6421
6422/*
6423 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
6424 * then all holes in the requested range will be accounted for.
6425 */
6426unsigned long __init __absent_pages_in_range(int nid,
6427				unsigned long range_start_pfn,
6428				unsigned long range_end_pfn)
6429{
6430	unsigned long nr_absent = range_end_pfn - range_start_pfn;
6431	unsigned long start_pfn, end_pfn;
6432	int i;
6433
6434	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
6435		start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
6436		end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
6437		nr_absent -= end_pfn - start_pfn;
6438	}
6439	return nr_absent;
6440}
6441
6442/**
6443 * absent_pages_in_range - Return number of page frames in holes within a range
6444 * @start_pfn: The start PFN to start searching for holes
6445 * @end_pfn: The end PFN to stop searching for holes
6446 *
6447 * Return: the number of pages frames in memory holes within a range.
6448 */
6449unsigned long __init absent_pages_in_range(unsigned long start_pfn,
6450							unsigned long end_pfn)
6451{
6452	return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
6453}
6454
6455/* Return the number of page frames in holes in a zone on a node */
6456static unsigned long __init zone_absent_pages_in_node(int nid,
6457					unsigned long zone_type,
6458					unsigned long node_start_pfn,
6459					unsigned long node_end_pfn,
6460					unsigned long *ignored)
6461{
6462	unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
6463	unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
6464	unsigned long zone_start_pfn, zone_end_pfn;
6465	unsigned long nr_absent;
6466
6467	/* When hotadd a new node from cpu_up(), the node should be empty */
6468	if (!node_start_pfn && !node_end_pfn)
6469		return 0;
6470
6471	zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
6472	zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
6473
6474	adjust_zone_range_for_zone_movable(nid, zone_type,
6475			node_start_pfn, node_end_pfn,
6476			&zone_start_pfn, &zone_end_pfn);
6477	nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
6478
6479	/*
6480	 * ZONE_MOVABLE handling.
6481	 * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
6482	 * and vice versa.
6483	 */
6484	if (mirrored_kernelcore && zone_movable_pfn[nid]) {
6485		unsigned long start_pfn, end_pfn;
6486		struct memblock_region *r;
6487
6488		for_each_memblock(memory, r) {
6489			start_pfn = clamp(memblock_region_memory_base_pfn(r),
6490					  zone_start_pfn, zone_end_pfn);
6491			end_pfn = clamp(memblock_region_memory_end_pfn(r),
6492					zone_start_pfn, zone_end_pfn);
6493
6494			if (zone_type == ZONE_MOVABLE &&
6495			    memblock_is_mirror(r))
6496				nr_absent += end_pfn - start_pfn;
6497
6498			if (zone_type == ZONE_NORMAL &&
6499			    !memblock_is_mirror(r))
6500				nr_absent += end_pfn - start_pfn;
6501		}
6502	}
6503
6504	return nr_absent;
6505}
6506
6507#else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6508static inline unsigned long __init zone_spanned_pages_in_node(int nid,
6509					unsigned long zone_type,
6510					unsigned long node_start_pfn,
6511					unsigned long node_end_pfn,
6512					unsigned long *zone_start_pfn,
6513					unsigned long *zone_end_pfn,
6514					unsigned long *zones_size)
6515{
6516	unsigned int zone;
6517
6518	*zone_start_pfn = node_start_pfn;
6519	for (zone = 0; zone < zone_type; zone++)
6520		*zone_start_pfn += zones_size[zone];
6521
6522	*zone_end_pfn = *zone_start_pfn + zones_size[zone_type];
6523
6524	return zones_size[zone_type];
6525}
6526
6527static inline unsigned long __init zone_absent_pages_in_node(int nid,
6528						unsigned long zone_type,
6529						unsigned long node_start_pfn,
6530						unsigned long node_end_pfn,
6531						unsigned long *zholes_size)
6532{
6533	if (!zholes_size)
6534		return 0;
6535
6536	return zholes_size[zone_type];
6537}
6538
6539#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6540
6541static void __init calculate_node_totalpages(struct pglist_data *pgdat,
6542						unsigned long node_start_pfn,
6543						unsigned long node_end_pfn,
6544						unsigned long *zones_size,
6545						unsigned long *zholes_size)
6546{
6547	unsigned long realtotalpages = 0, totalpages = 0;
6548	enum zone_type i;
6549
6550	for (i = 0; i < MAX_NR_ZONES; i++) {
6551		struct zone *zone = pgdat->node_zones + i;
6552		unsigned long zone_start_pfn, zone_end_pfn;
6553		unsigned long size, real_size;
6554
6555		size = zone_spanned_pages_in_node(pgdat->node_id, i,
6556						  node_start_pfn,
6557						  node_end_pfn,
6558						  &zone_start_pfn,
6559						  &zone_end_pfn,
6560						  zones_size);
6561		real_size = size - zone_absent_pages_in_node(pgdat->node_id, i,
6562						  node_start_pfn, node_end_pfn,
6563						  zholes_size);
6564		if (size)
6565			zone->zone_start_pfn = zone_start_pfn;
6566		else
6567			zone->zone_start_pfn = 0;
6568		zone->spanned_pages = size;
6569		zone->present_pages = real_size;
6570
6571		totalpages += size;
6572		realtotalpages += real_size;
6573	}
6574
6575	pgdat->node_spanned_pages = totalpages;
6576	pgdat->node_present_pages = realtotalpages;
6577	printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
6578							realtotalpages);
6579}
6580
6581#ifndef CONFIG_SPARSEMEM
6582/*
6583 * Calculate the size of the zone->blockflags rounded to an unsigned long
6584 * Start by making sure zonesize is a multiple of pageblock_order by rounding
6585 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
6586 * round what is now in bits to nearest long in bits, then return it in
6587 * bytes.
 
 
 
 
 
 
 
 
 
 
6588 */
6589static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
6590{
6591	unsigned long usemapsize;
6592
6593	zonesize += zone_start_pfn & (pageblock_nr_pages-1);
6594	usemapsize = roundup(zonesize, pageblock_nr_pages);
6595	usemapsize = usemapsize >> pageblock_order;
6596	usemapsize *= NR_PAGEBLOCK_BITS;
6597	usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
6598
6599	return usemapsize / 8;
6600}
6601
6602static void __ref setup_usemap(struct pglist_data *pgdat,
6603				struct zone *zone,
6604				unsigned long zone_start_pfn,
6605				unsigned long zonesize)
6606{
6607	unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
6608	zone->pageblock_flags = NULL;
6609	if (usemapsize) {
6610		zone->pageblock_flags =
6611			memblock_alloc_node(usemapsize, SMP_CACHE_BYTES,
6612					    pgdat->node_id);
6613		if (!zone->pageblock_flags)
6614			panic("Failed to allocate %ld bytes for zone %s pageblock flags on node %d\n",
6615			      usemapsize, zone->name, pgdat->node_id);
6616	}
6617}
6618#else
6619static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
6620				unsigned long zone_start_pfn, unsigned long zonesize) {}
6621#endif /* CONFIG_SPARSEMEM */
6622
6623#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
6624
6625/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
6626void __init set_pageblock_order(void)
6627{
6628	unsigned int order;
6629
6630	/* Check that pageblock_nr_pages has not already been setup */
6631	if (pageblock_order)
6632		return;
6633
6634	if (HPAGE_SHIFT > PAGE_SHIFT)
6635		order = HUGETLB_PAGE_ORDER;
6636	else
6637		order = MAX_ORDER - 1;
6638
6639	/*
6640	 * Assume the largest contiguous order of interest is a huge page.
6641	 * This value may be variable depending on boot parameters on IA64 and
6642	 * powerpc.
6643	 */
6644	pageblock_order = order;
6645}
6646#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
6647
6648/*
6649 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
6650 * is unused as pageblock_order is set at compile-time. See
6651 * include/linux/pageblock-flags.h for the values of pageblock_order based on
6652 * the kernel config
6653 */
6654void __init set_pageblock_order(void)
6655{
6656}
6657
6658#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
 
6659
6660static unsigned long __init calc_memmap_size(unsigned long spanned_pages,
6661						unsigned long present_pages)
6662{
6663	unsigned long pages = spanned_pages;
6664
6665	/*
6666	 * Provide a more accurate estimation if there are holes within
6667	 * the zone and SPARSEMEM is in use. If there are holes within the
6668	 * zone, each populated memory region may cost us one or two extra
6669	 * memmap pages due to alignment because memmap pages for each
6670	 * populated regions may not be naturally aligned on page boundary.
6671	 * So the (present_pages >> 4) heuristic is a tradeoff for that.
6672	 */
6673	if (spanned_pages > present_pages + (present_pages >> 4) &&
6674	    IS_ENABLED(CONFIG_SPARSEMEM))
6675		pages = present_pages;
6676
6677	return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
6678}
6679
6680#ifdef CONFIG_TRANSPARENT_HUGEPAGE
6681static void pgdat_init_split_queue(struct pglist_data *pgdat)
6682{
6683	struct deferred_split *ds_queue = &pgdat->deferred_split_queue;
6684
6685	spin_lock_init(&ds_queue->split_queue_lock);
6686	INIT_LIST_HEAD(&ds_queue->split_queue);
6687	ds_queue->split_queue_len = 0;
6688}
6689#else
6690static void pgdat_init_split_queue(struct pglist_data *pgdat) {}
6691#endif
6692
6693#ifdef CONFIG_COMPACTION
6694static void pgdat_init_kcompactd(struct pglist_data *pgdat)
6695{
6696	init_waitqueue_head(&pgdat->kcompactd_wait);
6697}
6698#else
6699static void pgdat_init_kcompactd(struct pglist_data *pgdat) {}
6700#endif
6701
6702static void __meminit pgdat_init_internals(struct pglist_data *pgdat)
6703{
6704	pgdat_resize_init(pgdat);
6705
6706	pgdat_init_split_queue(pgdat);
6707	pgdat_init_kcompactd(pgdat);
6708
6709	init_waitqueue_head(&pgdat->kswapd_wait);
6710	init_waitqueue_head(&pgdat->pfmemalloc_wait);
6711
6712	pgdat_page_ext_init(pgdat);
6713	spin_lock_init(&pgdat->lru_lock);
6714	lruvec_init(node_lruvec(pgdat));
6715}
6716
6717static void __meminit zone_init_internals(struct zone *zone, enum zone_type idx, int nid,
6718							unsigned long remaining_pages)
6719{
6720	atomic_long_set(&zone->managed_pages, remaining_pages);
6721	zone_set_nid(zone, nid);
6722	zone->name = zone_names[idx];
6723	zone->zone_pgdat = NODE_DATA(nid);
6724	spin_lock_init(&zone->lock);
6725	zone_seqlock_init(zone);
6726	zone_pcp_init(zone);
6727}
6728
6729/*
6730 * Set up the zone data structures
6731 * - init pgdat internals
6732 * - init all zones belonging to this node
6733 *
6734 * NOTE: this function is only called during memory hotplug
6735 */
6736#ifdef CONFIG_MEMORY_HOTPLUG
6737void __ref free_area_init_core_hotplug(int nid)
6738{
6739	enum zone_type z;
6740	pg_data_t *pgdat = NODE_DATA(nid);
6741
6742	pgdat_init_internals(pgdat);
6743	for (z = 0; z < MAX_NR_ZONES; z++)
6744		zone_init_internals(&pgdat->node_zones[z], z, nid, 0);
 
6745}
6746#endif
6747
6748/*
6749 * Set up the zone data structures:
6750 *   - mark all pages reserved
6751 *   - mark all memory queues empty
6752 *   - clear the memory bitmaps
6753 *
6754 * NOTE: pgdat should get zeroed by caller.
6755 * NOTE: this function is only called during early init.
6756 */
6757static void __init free_area_init_core(struct pglist_data *pgdat)
6758{
6759	enum zone_type j;
6760	int nid = pgdat->node_id;
6761
6762	pgdat_init_internals(pgdat);
6763	pgdat->per_cpu_nodestats = &boot_nodestats;
6764
6765	for (j = 0; j < MAX_NR_ZONES; j++) {
6766		struct zone *zone = pgdat->node_zones + j;
6767		unsigned long size, freesize, memmap_pages;
6768		unsigned long zone_start_pfn = zone->zone_start_pfn;
6769
6770		size = zone->spanned_pages;
6771		freesize = zone->present_pages;
6772
6773		/*
6774		 * Adjust freesize so that it accounts for how much memory
6775		 * is used by this zone for memmap. This affects the watermark
6776		 * and per-cpu initialisations
6777		 */
6778		memmap_pages = calc_memmap_size(size, freesize);
6779		if (!is_highmem_idx(j)) {
6780			if (freesize >= memmap_pages) {
6781				freesize -= memmap_pages;
6782				if (memmap_pages)
6783					printk(KERN_DEBUG
6784					       "  %s zone: %lu pages used for memmap\n",
6785					       zone_names[j], memmap_pages);
6786			} else
6787				pr_warn("  %s zone: %lu pages exceeds freesize %lu\n",
6788					zone_names[j], memmap_pages, freesize);
6789		}
6790
6791		/* Account for reserved pages */
6792		if (j == 0 && freesize > dma_reserve) {
6793			freesize -= dma_reserve;
6794			printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
6795					zone_names[0], dma_reserve);
6796		}
6797
6798		if (!is_highmem_idx(j))
6799			nr_kernel_pages += freesize;
6800		/* Charge for highmem memmap if there are enough kernel pages */
6801		else if (nr_kernel_pages > memmap_pages * 2)
6802			nr_kernel_pages -= memmap_pages;
6803		nr_all_pages += freesize;
6804
 
 
 
 
6805		/*
6806		 * Set an approximate value for lowmem here, it will be adjusted
6807		 * when the bootmem allocator frees pages into the buddy system.
6808		 * And all highmem pages will be managed by the buddy system.
6809		 */
6810		zone_init_internals(zone, j, nid, freesize);
6811
6812		if (!size)
6813			continue;
6814
6815		set_pageblock_order();
6816		setup_usemap(pgdat, zone, zone_start_pfn, size);
6817		init_currently_empty_zone(zone, zone_start_pfn, size);
6818		memmap_init(size, nid, j, zone_start_pfn);
6819	}
6820}
6821
6822#ifdef CONFIG_FLAT_NODE_MEM_MAP
6823static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
6824{
6825	unsigned long __maybe_unused start = 0;
6826	unsigned long __maybe_unused offset = 0;
6827
6828	/* Skip empty nodes */
6829	if (!pgdat->node_spanned_pages)
 
6830		return;
6831
6832	start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
6833	offset = pgdat->node_start_pfn - start;
6834	/* ia64 gets its own node_mem_map, before this, without bootmem */
6835	if (!pgdat->node_mem_map) {
6836		unsigned long size, end;
6837		struct page *map;
6838
6839		/*
6840		 * The zone's endpoints aren't required to be MAX_ORDER
6841		 * aligned but the node_mem_map endpoints must be in order
6842		 * for the buddy allocator to function correctly.
6843		 */
6844		end = pgdat_end_pfn(pgdat);
6845		end = ALIGN(end, MAX_ORDER_NR_PAGES);
6846		size =  (end - start) * sizeof(struct page);
6847		map = memblock_alloc_node(size, SMP_CACHE_BYTES,
6848					  pgdat->node_id);
6849		if (!map)
6850			panic("Failed to allocate %ld bytes for node %d memory map\n",
6851			      size, pgdat->node_id);
6852		pgdat->node_mem_map = map + offset;
6853	}
6854	pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
6855				__func__, pgdat->node_id, (unsigned long)pgdat,
6856				(unsigned long)pgdat->node_mem_map);
6857#ifndef CONFIG_NEED_MULTIPLE_NODES
6858	/*
6859	 * With no DISCONTIG, the global mem_map is just set as node 0's
6860	 */
6861	if (pgdat == NODE_DATA(0)) {
6862		mem_map = NODE_DATA(0)->node_mem_map;
6863#if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM)
6864		if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
6865			mem_map -= offset;
6866#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6867	}
6868#endif
6869}
6870#else
6871static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { }
6872#endif /* CONFIG_FLAT_NODE_MEM_MAP */
6873
6874#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
6875static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
6876{
6877	pgdat->first_deferred_pfn = ULONG_MAX;
6878}
6879#else
6880static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
6881#endif
6882
6883void __init free_area_init_node(int nid, unsigned long *zones_size,
6884				   unsigned long node_start_pfn,
6885				   unsigned long *zholes_size)
6886{
6887	pg_data_t *pgdat = NODE_DATA(nid);
6888	unsigned long start_pfn = 0;
6889	unsigned long end_pfn = 0;
6890
6891	/* pg_data_t should be reset to zero when it's allocated */
6892	WARN_ON(pgdat->nr_zones || pgdat->kswapd_classzone_idx);
6893
6894	pgdat->node_id = nid;
6895	pgdat->node_start_pfn = node_start_pfn;
6896	pgdat->per_cpu_nodestats = NULL;
6897#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
6898	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
6899	pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
6900		(u64)start_pfn << PAGE_SHIFT,
6901		end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
6902#else
6903	start_pfn = node_start_pfn;
6904#endif
6905	calculate_node_totalpages(pgdat, start_pfn, end_pfn,
6906				  zones_size, zholes_size);
6907
6908	alloc_node_mem_map(pgdat);
6909	pgdat_set_deferred_range(pgdat);
6910
6911	free_area_init_core(pgdat);
6912}
6913
6914#if !defined(CONFIG_FLAT_NODE_MEM_MAP)
6915/*
6916 * Zero all valid struct pages in range [spfn, epfn), return number of struct
6917 * pages zeroed
6918 */
6919static u64 zero_pfn_range(unsigned long spfn, unsigned long epfn)
6920{
6921	unsigned long pfn;
6922	u64 pgcnt = 0;
6923
6924	for (pfn = spfn; pfn < epfn; pfn++) {
6925		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
6926			pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
6927				+ pageblock_nr_pages - 1;
6928			continue;
6929		}
6930		mm_zero_struct_page(pfn_to_page(pfn));
6931		pgcnt++;
6932	}
6933
6934	return pgcnt;
6935}
 
6936
6937/*
6938 * Only struct pages that are backed by physical memory are zeroed and
6939 * initialized by going through __init_single_page(). But, there are some
6940 * struct pages which are reserved in memblock allocator and their fields
6941 * may be accessed (for example page_to_pfn() on some configuration accesses
6942 * flags). We must explicitly zero those struct pages.
6943 *
6944 * This function also addresses a similar issue where struct pages are left
6945 * uninitialized because the physical address range is not covered by
6946 * memblock.memory or memblock.reserved. That could happen when memblock
6947 * layout is manually configured via memmap=.
6948 */
6949void __init zero_resv_unavail(void)
6950{
6951	phys_addr_t start, end;
6952	u64 i, pgcnt;
6953	phys_addr_t next = 0;
6954
6955	/*
6956	 * Loop through unavailable ranges not covered by memblock.memory.
6957	 */
6958	pgcnt = 0;
6959	for_each_mem_range(i, &memblock.memory, NULL,
6960			NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) {
6961		if (next < start)
6962			pgcnt += zero_pfn_range(PFN_DOWN(next), PFN_UP(start));
6963		next = end;
6964	}
6965	pgcnt += zero_pfn_range(PFN_DOWN(next), max_pfn);
6966
6967	/*
6968	 * Struct pages that do not have backing memory. This could be because
6969	 * firmware is using some of this memory, or for some other reasons.
6970	 */
6971	if (pgcnt)
6972		pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt);
6973}
6974#endif /* !CONFIG_FLAT_NODE_MEM_MAP */
6975
6976#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
6977
6978#if MAX_NUMNODES > 1
6979/*
6980 * Figure out the number of possible node ids.
 
6981 */
6982void __init setup_nr_node_ids(void)
6983{
6984	unsigned int highest;
6985
6986	highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES);
6987	nr_node_ids = highest + 1;
6988}
6989#endif
6990
6991/**
6992 * node_map_pfn_alignment - determine the maximum internode alignment
6993 *
6994 * This function should be called after node map is populated and sorted.
6995 * It calculates the maximum power of two alignment which can distinguish
6996 * all the nodes.
6997 *
6998 * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
6999 * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)).  If the
7000 * nodes are shifted by 256MiB, 256MiB.  Note that if only the last node is
7001 * shifted, 1GiB is enough and this function will indicate so.
7002 *
7003 * This is used to test whether pfn -> nid mapping of the chosen memory
7004 * model has fine enough granularity to avoid incorrect mapping for the
7005 * populated node map.
7006 *
7007 * Return: the determined alignment in pfn's.  0 if there is no alignment
7008 * requirement (single node).
7009 */
7010unsigned long __init node_map_pfn_alignment(void)
7011{
7012	unsigned long accl_mask = 0, last_end = 0;
7013	unsigned long start, end, mask;
7014	int last_nid = NUMA_NO_NODE;
7015	int i, nid;
7016
7017	for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
7018		if (!start || last_nid < 0 || last_nid == nid) {
7019			last_nid = nid;
7020			last_end = end;
7021			continue;
7022		}
7023
7024		/*
7025		 * Start with a mask granular enough to pin-point to the
7026		 * start pfn and tick off bits one-by-one until it becomes
7027		 * too coarse to separate the current node from the last.
7028		 */
7029		mask = ~((1 << __ffs(start)) - 1);
7030		while (mask && last_end <= (start & (mask << 1)))
7031			mask <<= 1;
7032
7033		/* accumulate all internode masks */
7034		accl_mask |= mask;
7035	}
7036
7037	/* convert mask to number of pages */
7038	return ~accl_mask + 1;
7039}
7040
7041/* Find the lowest pfn for a node */
7042static unsigned long __init find_min_pfn_for_node(int nid)
7043{
7044	unsigned long min_pfn = ULONG_MAX;
7045	unsigned long start_pfn;
7046	int i;
7047
7048	for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
7049		min_pfn = min(min_pfn, start_pfn);
7050
7051	if (min_pfn == ULONG_MAX) {
7052		pr_warn("Could not find start_pfn for node %d\n", nid);
7053		return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
7054	}
7055
7056	return min_pfn;
7057}
7058
7059/**
7060 * find_min_pfn_with_active_regions - Find the minimum PFN registered
7061 *
7062 * Return: the minimum PFN based on information provided via
7063 * memblock_set_node().
7064 */
7065unsigned long __init find_min_pfn_with_active_regions(void)
7066{
7067	return find_min_pfn_for_node(MAX_NUMNODES);
7068}
7069
7070/*
7071 * early_calculate_totalpages()
7072 * Sum pages in active regions for movable zone.
7073 * Populate N_MEMORY for calculating usable_nodes.
7074 */
7075static unsigned long __init early_calculate_totalpages(void)
7076{
7077	unsigned long totalpages = 0;
7078	unsigned long start_pfn, end_pfn;
7079	int i, nid;
7080
7081	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
7082		unsigned long pages = end_pfn - start_pfn;
7083
7084		totalpages += pages;
7085		if (pages)
7086			node_set_state(nid, N_MEMORY);
7087	}
7088	return totalpages;
7089}
7090
7091/*
7092 * Find the PFN the Movable zone begins in each node. Kernel memory
7093 * is spread evenly between nodes as long as the nodes have enough
7094 * memory. When they don't, some nodes will have more kernelcore than
7095 * others
7096 */
7097static void __init find_zone_movable_pfns_for_nodes(void)
7098{
7099	int i, nid;
7100	unsigned long usable_startpfn;
7101	unsigned long kernelcore_node, kernelcore_remaining;
7102	/* save the state before borrow the nodemask */
7103	nodemask_t saved_node_state = node_states[N_MEMORY];
7104	unsigned long totalpages = early_calculate_totalpages();
7105	int usable_nodes = nodes_weight(node_states[N_MEMORY]);
7106	struct memblock_region *r;
7107
7108	/* Need to find movable_zone earlier when movable_node is specified. */
7109	find_usable_zone_for_movable();
7110
7111	/*
7112	 * If movable_node is specified, ignore kernelcore and movablecore
7113	 * options.
7114	 */
7115	if (movable_node_is_enabled()) {
7116		for_each_memblock(memory, r) {
7117			if (!memblock_is_hotpluggable(r))
7118				continue;
7119
7120			nid = r->nid;
7121
7122			usable_startpfn = PFN_DOWN(r->base);
7123			zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
7124				min(usable_startpfn, zone_movable_pfn[nid]) :
7125				usable_startpfn;
7126		}
7127
7128		goto out2;
7129	}
7130
7131	/*
7132	 * If kernelcore=mirror is specified, ignore movablecore option
7133	 */
7134	if (mirrored_kernelcore) {
7135		bool mem_below_4gb_not_mirrored = false;
7136
7137		for_each_memblock(memory, r) {
7138			if (memblock_is_mirror(r))
7139				continue;
7140
7141			nid = r->nid;
7142
7143			usable_startpfn = memblock_region_memory_base_pfn(r);
7144
7145			if (usable_startpfn < 0x100000) {
7146				mem_below_4gb_not_mirrored = true;
7147				continue;
7148			}
7149
7150			zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
7151				min(usable_startpfn, zone_movable_pfn[nid]) :
7152				usable_startpfn;
7153		}
7154
7155		if (mem_below_4gb_not_mirrored)
7156			pr_warn("This configuration results in unmirrored kernel memory.");
7157
7158		goto out2;
7159	}
7160
7161	/*
7162	 * If kernelcore=nn% or movablecore=nn% was specified, calculate the
7163	 * amount of necessary memory.
7164	 */
7165	if (required_kernelcore_percent)
7166		required_kernelcore = (totalpages * 100 * required_kernelcore_percent) /
7167				       10000UL;
7168	if (required_movablecore_percent)
7169		required_movablecore = (totalpages * 100 * required_movablecore_percent) /
7170					10000UL;
7171
7172	/*
7173	 * If movablecore= was specified, calculate what size of
7174	 * kernelcore that corresponds so that memory usable for
7175	 * any allocation type is evenly spread. If both kernelcore
7176	 * and movablecore are specified, then the value of kernelcore
7177	 * will be used for required_kernelcore if it's greater than
7178	 * what movablecore would have allowed.
7179	 */
7180	if (required_movablecore) {
7181		unsigned long corepages;
7182
7183		/*
7184		 * Round-up so that ZONE_MOVABLE is at least as large as what
7185		 * was requested by the user
7186		 */
7187		required_movablecore =
7188			roundup(required_movablecore, MAX_ORDER_NR_PAGES);
7189		required_movablecore = min(totalpages, required_movablecore);
7190		corepages = totalpages - required_movablecore;
7191
7192		required_kernelcore = max(required_kernelcore, corepages);
7193	}
7194
 
7195	/*
7196	 * If kernelcore was not specified or kernelcore size is larger
7197	 * than totalpages, there is no ZONE_MOVABLE.
7198	 */
7199	if (!required_kernelcore || required_kernelcore >= totalpages)
7200		goto out;
7201
7202	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
7203	usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
7204
7205restart:
7206	/* Spread kernelcore memory as evenly as possible throughout nodes */
7207	kernelcore_node = required_kernelcore / usable_nodes;
7208	for_each_node_state(nid, N_MEMORY) {
7209		unsigned long start_pfn, end_pfn;
7210
7211		/*
7212		 * Recalculate kernelcore_node if the division per node
7213		 * now exceeds what is necessary to satisfy the requested
7214		 * amount of memory for the kernel
7215		 */
7216		if (required_kernelcore < kernelcore_node)
7217			kernelcore_node = required_kernelcore / usable_nodes;
7218
7219		/*
7220		 * As the map is walked, we track how much memory is usable
7221		 * by the kernel using kernelcore_remaining. When it is
7222		 * 0, the rest of the node is usable by ZONE_MOVABLE
7223		 */
7224		kernelcore_remaining = kernelcore_node;
7225
7226		/* Go through each range of PFNs within this node */
7227		for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
7228			unsigned long size_pages;
7229
7230			start_pfn = max(start_pfn, zone_movable_pfn[nid]);
7231			if (start_pfn >= end_pfn)
7232				continue;
7233
7234			/* Account for what is only usable for kernelcore */
7235			if (start_pfn < usable_startpfn) {
7236				unsigned long kernel_pages;
7237				kernel_pages = min(end_pfn, usable_startpfn)
7238								- start_pfn;
7239
7240				kernelcore_remaining -= min(kernel_pages,
7241							kernelcore_remaining);
7242				required_kernelcore -= min(kernel_pages,
7243							required_kernelcore);
7244
7245				/* Continue if range is now fully accounted */
7246				if (end_pfn <= usable_startpfn) {
7247
7248					/*
7249					 * Push zone_movable_pfn to the end so
7250					 * that if we have to rebalance
7251					 * kernelcore across nodes, we will
7252					 * not double account here
7253					 */
7254					zone_movable_pfn[nid] = end_pfn;
7255					continue;
7256				}
7257				start_pfn = usable_startpfn;
7258			}
7259
7260			/*
7261			 * The usable PFN range for ZONE_MOVABLE is from
7262			 * start_pfn->end_pfn. Calculate size_pages as the
7263			 * number of pages used as kernelcore
7264			 */
7265			size_pages = end_pfn - start_pfn;
7266			if (size_pages > kernelcore_remaining)
7267				size_pages = kernelcore_remaining;
7268			zone_movable_pfn[nid] = start_pfn + size_pages;
7269
7270			/*
7271			 * Some kernelcore has been met, update counts and
7272			 * break if the kernelcore for this node has been
7273			 * satisfied
7274			 */
7275			required_kernelcore -= min(required_kernelcore,
7276								size_pages);
7277			kernelcore_remaining -= size_pages;
7278			if (!kernelcore_remaining)
7279				break;
7280		}
7281	}
 
7282
7283	/*
7284	 * If there is still required_kernelcore, we do another pass with one
7285	 * less node in the count. This will push zone_movable_pfn[nid] further
7286	 * along on the nodes that still have memory until kernelcore is
7287	 * satisfied
7288	 */
7289	usable_nodes--;
7290	if (usable_nodes && required_kernelcore > usable_nodes)
7291		goto restart;
7292
7293out2:
7294	/* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
7295	for (nid = 0; nid < MAX_NUMNODES; nid++)
7296		zone_movable_pfn[nid] =
7297			roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
7298
7299out:
7300	/* restore the node_state */
7301	node_states[N_MEMORY] = saved_node_state;
7302}
7303
7304/* Any regular or high memory on that node ? */
7305static void check_for_memory(pg_data_t *pgdat, int nid)
7306{
7307	enum zone_type zone_type;
7308
7309	for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
7310		struct zone *zone = &pgdat->node_zones[zone_type];
7311		if (populated_zone(zone)) {
7312			if (IS_ENABLED(CONFIG_HIGHMEM))
7313				node_set_state(nid, N_HIGH_MEMORY);
7314			if (zone_type <= ZONE_NORMAL)
7315				node_set_state(nid, N_NORMAL_MEMORY);
7316			break;
7317		}
7318	}
7319}
7320
7321/**
7322 * free_area_init_nodes - Initialise all pg_data_t and zone data
7323 * @max_zone_pfn: an array of max PFNs for each zone
7324 *
7325 * This will call free_area_init_node() for each active node in the system.
7326 * Using the page ranges provided by memblock_set_node(), the size of each
7327 * zone in each node and their holes is calculated. If the maximum PFN
7328 * between two adjacent zones match, it is assumed that the zone is empty.
7329 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
7330 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
7331 * starts where the previous one ended. For example, ZONE_DMA32 starts
7332 * at arch_max_dma_pfn.
7333 */
7334void __init free_area_init_nodes(unsigned long *max_zone_pfn)
7335{
7336	unsigned long start_pfn, end_pfn;
7337	int i, nid;
7338
7339	/* Record where the zone boundaries are */
7340	memset(arch_zone_lowest_possible_pfn, 0,
7341				sizeof(arch_zone_lowest_possible_pfn));
7342	memset(arch_zone_highest_possible_pfn, 0,
7343				sizeof(arch_zone_highest_possible_pfn));
7344
7345	start_pfn = find_min_pfn_with_active_regions();
7346
7347	for (i = 0; i < MAX_NR_ZONES; i++) {
7348		if (i == ZONE_MOVABLE)
7349			continue;
7350
7351		end_pfn = max(max_zone_pfn[i], start_pfn);
7352		arch_zone_lowest_possible_pfn[i] = start_pfn;
7353		arch_zone_highest_possible_pfn[i] = end_pfn;
7354
7355		start_pfn = end_pfn;
7356	}
7357
7358	/* Find the PFNs that ZONE_MOVABLE begins at in each node */
7359	memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
7360	find_zone_movable_pfns_for_nodes();
7361
7362	/* Print out the zone ranges */
7363	pr_info("Zone ranges:\n");
7364	for (i = 0; i < MAX_NR_ZONES; i++) {
7365		if (i == ZONE_MOVABLE)
7366			continue;
7367		pr_info("  %-8s ", zone_names[i]);
7368		if (arch_zone_lowest_possible_pfn[i] ==
7369				arch_zone_highest_possible_pfn[i])
7370			pr_cont("empty\n");
7371		else
7372			pr_cont("[mem %#018Lx-%#018Lx]\n",
7373				(u64)arch_zone_lowest_possible_pfn[i]
7374					<< PAGE_SHIFT,
7375				((u64)arch_zone_highest_possible_pfn[i]
7376					<< PAGE_SHIFT) - 1);
7377	}
7378
7379	/* Print out the PFNs ZONE_MOVABLE begins at in each node */
7380	pr_info("Movable zone start for each node\n");
7381	for (i = 0; i < MAX_NUMNODES; i++) {
7382		if (zone_movable_pfn[i])
7383			pr_info("  Node %d: %#018Lx\n", i,
7384			       (u64)zone_movable_pfn[i] << PAGE_SHIFT);
7385	}
7386
7387	/*
7388	 * Print out the early node map, and initialize the
7389	 * subsection-map relative to active online memory ranges to
7390	 * enable future "sub-section" extensions of the memory map.
7391	 */
7392	pr_info("Early memory node ranges\n");
7393	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
7394		pr_info("  node %3d: [mem %#018Lx-%#018Lx]\n", nid,
7395			(u64)start_pfn << PAGE_SHIFT,
7396			((u64)end_pfn << PAGE_SHIFT) - 1);
7397		subsection_map_init(start_pfn, end_pfn - start_pfn);
7398	}
7399
7400	/* Initialise every node */
7401	mminit_verify_pageflags_layout();
7402	setup_nr_node_ids();
7403	zero_resv_unavail();
7404	for_each_online_node(nid) {
7405		pg_data_t *pgdat = NODE_DATA(nid);
7406		free_area_init_node(nid, NULL,
7407				find_min_pfn_for_node(nid), NULL);
7408
7409		/* Any memory on that node */
7410		if (pgdat->node_present_pages)
7411			node_set_state(nid, N_MEMORY);
7412		check_for_memory(pgdat, nid);
7413	}
7414}
7415
7416static int __init cmdline_parse_core(char *p, unsigned long *core,
7417				     unsigned long *percent)
7418{
7419	unsigned long long coremem;
7420	char *endptr;
7421
7422	if (!p)
7423		return -EINVAL;
7424
7425	/* Value may be a percentage of total memory, otherwise bytes */
7426	coremem = simple_strtoull(p, &endptr, 0);
7427	if (*endptr == '%') {
7428		/* Paranoid check for percent values greater than 100 */
7429		WARN_ON(coremem > 100);
7430
7431		*percent = coremem;
7432	} else {
7433		coremem = memparse(p, &p);
7434		/* Paranoid check that UL is enough for the coremem value */
7435		WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
7436
7437		*core = coremem >> PAGE_SHIFT;
7438		*percent = 0UL;
7439	}
7440	return 0;
7441}
7442
7443/*
7444 * kernelcore=size sets the amount of memory for use for allocations that
7445 * cannot be reclaimed or migrated.
7446 */
7447static int __init cmdline_parse_kernelcore(char *p)
7448{
7449	/* parse kernelcore=mirror */
7450	if (parse_option_str(p, "mirror")) {
7451		mirrored_kernelcore = true;
7452		return 0;
7453	}
7454
7455	return cmdline_parse_core(p, &required_kernelcore,
7456				  &required_kernelcore_percent);
7457}
7458
7459/*
7460 * movablecore=size sets the amount of memory for use for allocations that
7461 * can be reclaimed or migrated.
7462 */
7463static int __init cmdline_parse_movablecore(char *p)
7464{
7465	return cmdline_parse_core(p, &required_movablecore,
7466				  &required_movablecore_percent);
7467}
7468
7469early_param("kernelcore", cmdline_parse_kernelcore);
7470early_param("movablecore", cmdline_parse_movablecore);
7471
7472#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
7473
7474void adjust_managed_page_count(struct page *page, long count)
7475{
7476	atomic_long_add(count, &page_zone(page)->managed_pages);
7477	totalram_pages_add(count);
7478#ifdef CONFIG_HIGHMEM
7479	if (PageHighMem(page))
7480		totalhigh_pages_add(count);
7481#endif
7482}
7483EXPORT_SYMBOL(adjust_managed_page_count);
7484
7485unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
7486{
7487	void *pos;
7488	unsigned long pages = 0;
7489
7490	start = (void *)PAGE_ALIGN((unsigned long)start);
7491	end = (void *)((unsigned long)end & PAGE_MASK);
7492	for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
7493		struct page *page = virt_to_page(pos);
7494		void *direct_map_addr;
7495
7496		/*
7497		 * 'direct_map_addr' might be different from 'pos'
7498		 * because some architectures' virt_to_page()
7499		 * work with aliases.  Getting the direct map
7500		 * address ensures that we get a _writeable_
7501		 * alias for the memset().
7502		 */
7503		direct_map_addr = page_address(page);
 
 
 
 
 
7504		if ((unsigned int)poison <= 0xFF)
7505			memset(direct_map_addr, poison, PAGE_SIZE);
7506
7507		free_reserved_page(page);
7508	}
7509
7510	if (pages && s)
7511		pr_info("Freeing %s memory: %ldK\n",
7512			s, pages << (PAGE_SHIFT - 10));
7513
7514	return pages;
7515}
7516
7517#ifdef	CONFIG_HIGHMEM
7518void free_highmem_page(struct page *page)
7519{
7520	__free_reserved_page(page);
7521	totalram_pages_inc();
7522	atomic_long_inc(&page_zone(page)->managed_pages);
7523	totalhigh_pages_inc();
7524}
7525#endif
7526
7527
7528void __init mem_init_print_info(const char *str)
7529{
7530	unsigned long physpages, codesize, datasize, rosize, bss_size;
7531	unsigned long init_code_size, init_data_size;
7532
7533	physpages = get_num_physpages();
7534	codesize = _etext - _stext;
7535	datasize = _edata - _sdata;
7536	rosize = __end_rodata - __start_rodata;
7537	bss_size = __bss_stop - __bss_start;
7538	init_data_size = __init_end - __init_begin;
7539	init_code_size = _einittext - _sinittext;
7540
7541	/*
7542	 * Detect special cases and adjust section sizes accordingly:
7543	 * 1) .init.* may be embedded into .data sections
7544	 * 2) .init.text.* may be out of [__init_begin, __init_end],
7545	 *    please refer to arch/tile/kernel/vmlinux.lds.S.
7546	 * 3) .rodata.* may be embedded into .text or .data sections.
7547	 */
7548#define adj_init_size(start, end, size, pos, adj) \
7549	do { \
7550		if (start <= pos && pos < end && size > adj) \
7551			size -= adj; \
7552	} while (0)
7553
7554	adj_init_size(__init_begin, __init_end, init_data_size,
7555		     _sinittext, init_code_size);
7556	adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
7557	adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
7558	adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
7559	adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
7560
7561#undef	adj_init_size
7562
7563	pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
7564#ifdef	CONFIG_HIGHMEM
7565		", %luK highmem"
7566#endif
7567		"%s%s)\n",
7568		nr_free_pages() << (PAGE_SHIFT - 10),
7569		physpages << (PAGE_SHIFT - 10),
7570		codesize >> 10, datasize >> 10, rosize >> 10,
7571		(init_data_size + init_code_size) >> 10, bss_size >> 10,
7572		(physpages - totalram_pages() - totalcma_pages) << (PAGE_SHIFT - 10),
7573		totalcma_pages << (PAGE_SHIFT - 10),
7574#ifdef	CONFIG_HIGHMEM
7575		totalhigh_pages() << (PAGE_SHIFT - 10),
7576#endif
7577		str ? ", " : "", str ? str : "");
7578}
7579
7580/**
7581 * set_dma_reserve - set the specified number of pages reserved in the first zone
7582 * @new_dma_reserve: The number of pages to mark reserved
7583 *
7584 * The per-cpu batchsize and zone watermarks are determined by managed_pages.
7585 * In the DMA zone, a significant percentage may be consumed by kernel image
7586 * and other unfreeable allocations which can skew the watermarks badly. This
7587 * function may optionally be used to account for unfreeable pages in the
7588 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
7589 * smaller per-cpu batchsize.
7590 */
7591void __init set_dma_reserve(unsigned long new_dma_reserve)
7592{
7593	dma_reserve = new_dma_reserve;
7594}
7595
7596void __init free_area_init(unsigned long *zones_size)
7597{
7598	zero_resv_unavail();
7599	free_area_init_node(0, zones_size,
7600			__pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
7601}
7602
7603static int page_alloc_cpu_dead(unsigned int cpu)
7604{
 
7605
7606	lru_add_drain_cpu(cpu);
 
7607	drain_pages(cpu);
7608
7609	/*
7610	 * Spill the event counters of the dead processor
7611	 * into the current processors event counters.
7612	 * This artificially elevates the count of the current
7613	 * processor.
7614	 */
7615	vm_events_fold_cpu(cpu);
7616
7617	/*
7618	 * Zero the differential counters of the dead processor
7619	 * so that the vm statistics are consistent.
7620	 *
7621	 * This is only okay since the processor is dead and cannot
7622	 * race with what we are doing.
7623	 */
7624	cpu_vm_stats_fold(cpu);
 
 
 
 
7625	return 0;
7626}
7627
7628#ifdef CONFIG_NUMA
7629int hashdist = HASHDIST_DEFAULT;
7630
7631static int __init set_hashdist(char *str)
7632{
7633	if (!str)
7634		return 0;
7635	hashdist = simple_strtoul(str, &str, 0);
7636	return 1;
 
7637}
7638__setup("hashdist=", set_hashdist);
7639#endif
7640
7641void __init page_alloc_init(void)
7642{
7643	int ret;
7644
7645#ifdef CONFIG_NUMA
7646	if (num_node_state(N_MEMORY) == 1)
7647		hashdist = 0;
7648#endif
7649
7650	ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC_DEAD,
7651					"mm/page_alloc:dead", NULL,
7652					page_alloc_cpu_dead);
7653	WARN_ON(ret < 0);
7654}
7655
7656/*
7657 * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio
7658 *	or min_free_kbytes changes.
7659 */
7660static void calculate_totalreserve_pages(void)
7661{
7662	struct pglist_data *pgdat;
7663	unsigned long reserve_pages = 0;
7664	enum zone_type i, j;
7665
7666	for_each_online_pgdat(pgdat) {
7667
7668		pgdat->totalreserve_pages = 0;
7669
7670		for (i = 0; i < MAX_NR_ZONES; i++) {
7671			struct zone *zone = pgdat->node_zones + i;
7672			long max = 0;
7673			unsigned long managed_pages = zone_managed_pages(zone);
7674
7675			/* Find valid and maximum lowmem_reserve in the zone */
7676			for (j = i; j < MAX_NR_ZONES; j++) {
7677				if (zone->lowmem_reserve[j] > max)
7678					max = zone->lowmem_reserve[j];
7679			}
7680
7681			/* we treat the high watermark as reserved pages. */
7682			max += high_wmark_pages(zone);
7683
7684			if (max > managed_pages)
7685				max = managed_pages;
7686
7687			pgdat->totalreserve_pages += max;
7688
7689			reserve_pages += max;
7690		}
7691	}
7692	totalreserve_pages = reserve_pages;
7693}
7694
7695/*
7696 * setup_per_zone_lowmem_reserve - called whenever
7697 *	sysctl_lowmem_reserve_ratio changes.  Ensures that each zone
7698 *	has a correct pages reserved value, so an adequate number of
7699 *	pages are left in the zone after a successful __alloc_pages().
7700 */
7701static void setup_per_zone_lowmem_reserve(void)
7702{
7703	struct pglist_data *pgdat;
7704	enum zone_type j, idx;
7705
7706	for_each_online_pgdat(pgdat) {
7707		for (j = 0; j < MAX_NR_ZONES; j++) {
7708			struct zone *zone = pgdat->node_zones + j;
7709			unsigned long managed_pages = zone_managed_pages(zone);
7710
7711			zone->lowmem_reserve[j] = 0;
7712
7713			idx = j;
7714			while (idx) {
7715				struct zone *lower_zone;
7716
7717				idx--;
7718				lower_zone = pgdat->node_zones + idx;
7719
7720				if (sysctl_lowmem_reserve_ratio[idx] < 1) {
7721					sysctl_lowmem_reserve_ratio[idx] = 0;
7722					lower_zone->lowmem_reserve[j] = 0;
7723				} else {
7724					lower_zone->lowmem_reserve[j] =
7725						managed_pages / sysctl_lowmem_reserve_ratio[idx];
7726				}
7727				managed_pages += zone_managed_pages(lower_zone);
7728			}
7729		}
7730	}
7731
7732	/* update totalreserve_pages */
7733	calculate_totalreserve_pages();
7734}
7735
7736static void __setup_per_zone_wmarks(void)
7737{
7738	unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
7739	unsigned long lowmem_pages = 0;
7740	struct zone *zone;
7741	unsigned long flags;
7742
7743	/* Calculate total number of !ZONE_HIGHMEM pages */
7744	for_each_zone(zone) {
7745		if (!is_highmem(zone))
7746			lowmem_pages += zone_managed_pages(zone);
7747	}
7748
7749	for_each_zone(zone) {
7750		u64 tmp;
7751
7752		spin_lock_irqsave(&zone->lock, flags);
7753		tmp = (u64)pages_min * zone_managed_pages(zone);
7754		do_div(tmp, lowmem_pages);
7755		if (is_highmem(zone)) {
7756			/*
7757			 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
7758			 * need highmem pages, so cap pages_min to a small
7759			 * value here.
7760			 *
7761			 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
7762			 * deltas control async page reclaim, and so should
7763			 * not be capped for highmem.
7764			 */
7765			unsigned long min_pages;
7766
7767			min_pages = zone_managed_pages(zone) / 1024;
7768			min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
7769			zone->_watermark[WMARK_MIN] = min_pages;
7770		} else {
7771			/*
7772			 * If it's a lowmem zone, reserve a number of pages
7773			 * proportionate to the zone's size.
7774			 */
7775			zone->_watermark[WMARK_MIN] = tmp;
7776		}
7777
7778		/*
7779		 * Set the kswapd watermarks distance according to the
7780		 * scale factor in proportion to available memory, but
7781		 * ensure a minimum size on small systems.
7782		 */
7783		tmp = max_t(u64, tmp >> 2,
7784			    mult_frac(zone_managed_pages(zone),
7785				      watermark_scale_factor, 10000));
7786
7787		zone->_watermark[WMARK_LOW]  = min_wmark_pages(zone) + tmp;
7788		zone->_watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;
7789		zone->watermark_boost = 0;
 
 
 
7790
7791		spin_unlock_irqrestore(&zone->lock, flags);
7792	}
7793
7794	/* update totalreserve_pages */
7795	calculate_totalreserve_pages();
7796}
7797
7798/**
7799 * setup_per_zone_wmarks - called when min_free_kbytes changes
7800 * or when memory is hot-{added|removed}
7801 *
7802 * Ensures that the watermark[min,low,high] values for each zone are set
7803 * correctly with respect to min_free_kbytes.
7804 */
7805void setup_per_zone_wmarks(void)
7806{
 
7807	static DEFINE_SPINLOCK(lock);
7808
7809	spin_lock(&lock);
7810	__setup_per_zone_wmarks();
7811	spin_unlock(&lock);
 
 
 
 
 
 
 
7812}
7813
7814/*
7815 * Initialise min_free_kbytes.
7816 *
7817 * For small machines we want it small (128k min).  For large machines
7818 * we want it large (64MB max).  But it is not linear, because network
7819 * bandwidth does not increase linearly with machine size.  We use
7820 *
7821 *	min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
7822 *	min_free_kbytes = sqrt(lowmem_kbytes * 16)
7823 *
7824 * which yields
7825 *
7826 * 16MB:	512k
7827 * 32MB:	724k
7828 * 64MB:	1024k
7829 * 128MB:	1448k
7830 * 256MB:	2048k
7831 * 512MB:	2896k
7832 * 1024MB:	4096k
7833 * 2048MB:	5792k
7834 * 4096MB:	8192k
7835 * 8192MB:	11584k
7836 * 16384MB:	16384k
7837 */
7838int __meminit init_per_zone_wmark_min(void)
7839{
7840	unsigned long lowmem_kbytes;
7841	int new_min_free_kbytes;
7842
7843	lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
7844	new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
7845
7846	if (new_min_free_kbytes > user_min_free_kbytes) {
7847		min_free_kbytes = new_min_free_kbytes;
7848		if (min_free_kbytes < 128)
7849			min_free_kbytes = 128;
7850		if (min_free_kbytes > 65536)
7851			min_free_kbytes = 65536;
7852	} else {
7853		pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
7854				new_min_free_kbytes, user_min_free_kbytes);
7855	}
 
 
 
 
 
7856	setup_per_zone_wmarks();
7857	refresh_zone_stat_thresholds();
7858	setup_per_zone_lowmem_reserve();
7859
7860#ifdef CONFIG_NUMA
7861	setup_min_unmapped_ratio();
7862	setup_min_slab_ratio();
7863#endif
7864
 
 
7865	return 0;
7866}
7867core_initcall(init_per_zone_wmark_min)
7868
7869/*
7870 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
7871 *	that we can call two helper functions whenever min_free_kbytes
7872 *	changes.
7873 */
7874int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
7875	void __user *buffer, size_t *length, loff_t *ppos)
7876{
7877	int rc;
7878
7879	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7880	if (rc)
7881		return rc;
7882
7883	if (write) {
7884		user_min_free_kbytes = min_free_kbytes;
7885		setup_per_zone_wmarks();
7886	}
7887	return 0;
7888}
7889
7890int watermark_boost_factor_sysctl_handler(struct ctl_table *table, int write,
7891	void __user *buffer, size_t *length, loff_t *ppos)
7892{
7893	int rc;
7894
7895	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7896	if (rc)
7897		return rc;
7898
7899	return 0;
7900}
7901
7902int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
7903	void __user *buffer, size_t *length, loff_t *ppos)
7904{
7905	int rc;
7906
7907	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7908	if (rc)
7909		return rc;
7910
7911	if (write)
7912		setup_per_zone_wmarks();
7913
7914	return 0;
7915}
7916
7917#ifdef CONFIG_NUMA
7918static void setup_min_unmapped_ratio(void)
7919{
7920	pg_data_t *pgdat;
7921	struct zone *zone;
7922
7923	for_each_online_pgdat(pgdat)
7924		pgdat->min_unmapped_pages = 0;
7925
7926	for_each_zone(zone)
7927		zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) *
7928						         sysctl_min_unmapped_ratio) / 100;
7929}
7930
7931
7932int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
7933	void __user *buffer, size_t *length, loff_t *ppos)
7934{
7935	int rc;
7936
7937	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7938	if (rc)
7939		return rc;
7940
7941	setup_min_unmapped_ratio();
7942
7943	return 0;
7944}
7945
7946static void setup_min_slab_ratio(void)
7947{
7948	pg_data_t *pgdat;
7949	struct zone *zone;
7950
7951	for_each_online_pgdat(pgdat)
7952		pgdat->min_slab_pages = 0;
7953
7954	for_each_zone(zone)
7955		zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) *
7956						     sysctl_min_slab_ratio) / 100;
7957}
7958
7959int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
7960	void __user *buffer, size_t *length, loff_t *ppos)
7961{
7962	int rc;
7963
7964	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7965	if (rc)
7966		return rc;
7967
7968	setup_min_slab_ratio();
7969
7970	return 0;
7971}
7972#endif
7973
7974/*
7975 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
7976 *	proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
7977 *	whenever sysctl_lowmem_reserve_ratio changes.
7978 *
7979 * The reserve ratio obviously has absolutely no relation with the
7980 * minimum watermarks. The lowmem reserve ratio can only make sense
7981 * if in function of the boot time zone sizes.
7982 */
7983int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
7984	void __user *buffer, size_t *length, loff_t *ppos)
7985{
 
 
7986	proc_dointvec_minmax(table, write, buffer, length, ppos);
 
 
 
 
 
 
7987	setup_per_zone_lowmem_reserve();
7988	return 0;
7989}
7990
7991/*
7992 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
7993 * cpu.  It is the fraction of total pages in each zone that a hot per cpu
7994 * pagelist can have before it gets flushed back to buddy allocator.
7995 */
7996int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write,
7997	void __user *buffer, size_t *length, loff_t *ppos)
7998{
7999	struct zone *zone;
8000	int old_percpu_pagelist_fraction;
8001	int ret;
8002
8003	mutex_lock(&pcp_batch_high_lock);
8004	old_percpu_pagelist_fraction = percpu_pagelist_fraction;
8005
8006	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
8007	if (!write || ret < 0)
8008		goto out;
8009
8010	/* Sanity checking to avoid pcp imbalance */
8011	if (percpu_pagelist_fraction &&
8012	    percpu_pagelist_fraction < MIN_PERCPU_PAGELIST_FRACTION) {
8013		percpu_pagelist_fraction = old_percpu_pagelist_fraction;
8014		ret = -EINVAL;
8015		goto out;
8016	}
8017
8018	/* No change? */
8019	if (percpu_pagelist_fraction == old_percpu_pagelist_fraction)
8020		goto out;
8021
8022	for_each_populated_zone(zone) {
8023		unsigned int cpu;
8024
8025		for_each_possible_cpu(cpu)
8026			pageset_set_high_and_batch(zone,
8027					per_cpu_ptr(zone->pageset, cpu));
8028	}
8029out:
8030	mutex_unlock(&pcp_batch_high_lock);
8031	return ret;
8032}
8033
8034#ifndef __HAVE_ARCH_RESERVED_KERNEL_PAGES
8035/*
8036 * Returns the number of pages that arch has reserved but
8037 * is not known to alloc_large_system_hash().
8038 */
8039static unsigned long __init arch_reserved_kernel_pages(void)
8040{
8041	return 0;
8042}
8043#endif
8044
8045/*
8046 * Adaptive scale is meant to reduce sizes of hash tables on large memory
8047 * machines. As memory size is increased the scale is also increased but at
8048 * slower pace.  Starting from ADAPT_SCALE_BASE (64G), every time memory
8049 * quadruples the scale is increased by one, which means the size of hash table
8050 * only doubles, instead of quadrupling as well.
8051 * Because 32-bit systems cannot have large physical memory, where this scaling
8052 * makes sense, it is disabled on such platforms.
8053 */
8054#if __BITS_PER_LONG > 32
8055#define ADAPT_SCALE_BASE	(64ul << 30)
8056#define ADAPT_SCALE_SHIFT	2
8057#define ADAPT_SCALE_NPAGES	(ADAPT_SCALE_BASE >> PAGE_SHIFT)
8058#endif
8059
8060/*
8061 * allocate a large system hash table from bootmem
8062 * - it is assumed that the hash table must contain an exact power-of-2
8063 *   quantity of entries
8064 * - limit is the number of hash buckets, not the total allocation size
8065 */
8066void *__init alloc_large_system_hash(const char *tablename,
8067				     unsigned long bucketsize,
8068				     unsigned long numentries,
8069				     int scale,
8070				     int flags,
8071				     unsigned int *_hash_shift,
8072				     unsigned int *_hash_mask,
8073				     unsigned long low_limit,
8074				     unsigned long high_limit)
8075{
8076	unsigned long long max = high_limit;
8077	unsigned long log2qty, size;
8078	void *table = NULL;
8079	gfp_t gfp_flags;
8080	bool virt;
8081
8082	/* allow the kernel cmdline to have a say */
8083	if (!numentries) {
8084		/* round applicable memory size up to nearest megabyte */
8085		numentries = nr_kernel_pages;
8086		numentries -= arch_reserved_kernel_pages();
8087
8088		/* It isn't necessary when PAGE_SIZE >= 1MB */
8089		if (PAGE_SHIFT < 20)
8090			numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
8091
8092#if __BITS_PER_LONG > 32
8093		if (!high_limit) {
8094			unsigned long adapt;
8095
8096			for (adapt = ADAPT_SCALE_NPAGES; adapt < numentries;
8097			     adapt <<= ADAPT_SCALE_SHIFT)
8098				scale++;
8099		}
 
8100#endif
 
 
8101
8102		/* limit to 1 bucket per 2^scale bytes of low memory */
8103		if (scale > PAGE_SHIFT)
8104			numentries >>= (scale - PAGE_SHIFT);
8105		else
8106			numentries <<= (PAGE_SHIFT - scale);
8107
8108		/* Make sure we've got at least a 0-order allocation.. */
8109		if (unlikely(flags & HASH_SMALL)) {
8110			/* Makes no sense without HASH_EARLY */
8111			WARN_ON(!(flags & HASH_EARLY));
8112			if (!(numentries >> *_hash_shift)) {
8113				numentries = 1UL << *_hash_shift;
8114				BUG_ON(!numentries);
8115			}
8116		} else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
8117			numentries = PAGE_SIZE / bucketsize;
8118	}
8119	numentries = roundup_pow_of_two(numentries);
8120
8121	/* limit allocation size to 1/16 total memory by default */
8122	if (max == 0) {
8123		max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
8124		do_div(max, bucketsize);
8125	}
8126	max = min(max, 0x80000000ULL);
8127
8128	if (numentries < low_limit)
8129		numentries = low_limit;
8130	if (numentries > max)
8131		numentries = max;
8132
8133	log2qty = ilog2(numentries);
8134
8135	gfp_flags = (flags & HASH_ZERO) ? GFP_ATOMIC | __GFP_ZERO : GFP_ATOMIC;
8136	do {
8137		virt = false;
8138		size = bucketsize << log2qty;
8139		if (flags & HASH_EARLY) {
8140			if (flags & HASH_ZERO)
8141				table = memblock_alloc(size, SMP_CACHE_BYTES);
8142			else
8143				table = memblock_alloc_raw(size,
8144							   SMP_CACHE_BYTES);
8145		} else if (get_order(size) >= MAX_ORDER || hashdist) {
8146			table = __vmalloc(size, gfp_flags, PAGE_KERNEL);
8147			virt = true;
8148		} else {
8149			/*
8150			 * If bucketsize is not a power-of-two, we may free
8151			 * some pages at the end of hash table which
8152			 * alloc_pages_exact() automatically does
8153			 */
8154			table = alloc_pages_exact(size, gfp_flags);
8155			kmemleak_alloc(table, size, 1, gfp_flags);
8156		}
8157	} while (!table && size > PAGE_SIZE && --log2qty);
8158
8159	if (!table)
8160		panic("Failed to allocate %s hash table\n", tablename);
8161
8162	pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
8163		tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
8164		virt ? "vmalloc" : "linear");
8165
8166	if (_hash_shift)
8167		*_hash_shift = log2qty;
8168	if (_hash_mask)
8169		*_hash_mask = (1 << log2qty) - 1;
8170
8171	return table;
8172}
8173
8174/*
8175 * This function checks whether pageblock includes unmovable pages or not.
8176 * If @count is not zero, it is okay to include less @count unmovable pages
8177 *
8178 * PageLRU check without isolation or lru_lock could race so that
8179 * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
8180 * check without lock_page also may miss some movable non-lru pages at
8181 * race condition. So you can't expect this function should be exact.
8182 */
8183bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
8184			 int migratetype, int flags)
8185{
8186	unsigned long found;
8187	unsigned long iter = 0;
8188	unsigned long pfn = page_to_pfn(page);
8189	const char *reason = "unmovable page";
8190
8191	/*
8192	 * TODO we could make this much more efficient by not checking every
8193	 * page in the range if we know all of them are in MOVABLE_ZONE and
8194	 * that the movable zone guarantees that pages are migratable but
8195	 * the later is not the case right now unfortunatelly. E.g. movablecore
8196	 * can still lead to having bootmem allocations in zone_movable.
8197	 */
8198
8199	if (is_migrate_cma_page(page)) {
8200		/*
8201		 * CMA allocations (alloc_contig_range) really need to mark
8202		 * isolate CMA pageblocks even when they are not movable in fact
8203		 * so consider them movable here.
8204		 */
8205		if (is_migrate_cma(migratetype))
8206			return false;
8207
8208		reason = "CMA page";
8209		goto unmovable;
8210	}
8211
8212	for (found = 0; iter < pageblock_nr_pages; iter++) {
8213		unsigned long check = pfn + iter;
8214
8215		if (!pfn_valid_within(check))
8216			continue;
8217
8218		page = pfn_to_page(check);
8219
8220		if (PageReserved(page))
8221			goto unmovable;
8222
8223		/*
8224		 * If the zone is movable and we have ruled out all reserved
8225		 * pages then it should be reasonably safe to assume the rest
8226		 * is movable.
8227		 */
8228		if (zone_idx(zone) == ZONE_MOVABLE)
8229			continue;
8230
8231		/*
8232		 * Hugepages are not in LRU lists, but they're movable.
8233		 * We need not scan over tail pages because we don't
8234		 * handle each tail page individually in migration.
8235		 */
8236		if (PageHuge(page)) {
8237			struct page *head = compound_head(page);
8238			unsigned int skip_pages;
8239
8240			if (!hugepage_migration_supported(page_hstate(head)))
8241				goto unmovable;
8242
8243			skip_pages = compound_nr(head) - (page - head);
8244			iter += skip_pages - 1;
8245			continue;
8246		}
8247
8248		/*
8249		 * We can't use page_count without pin a page
8250		 * because another CPU can free compound page.
8251		 * This check already skips compound tails of THP
8252		 * because their page->_refcount is zero at all time.
8253		 */
8254		if (!page_ref_count(page)) {
8255			if (PageBuddy(page))
8256				iter += (1 << page_order(page)) - 1;
8257			continue;
8258		}
8259
8260		/*
8261		 * The HWPoisoned page may be not in buddy system, and
8262		 * page_count() is not 0.
8263		 */
8264		if ((flags & SKIP_HWPOISON) && PageHWPoison(page))
8265			continue;
8266
8267		if (__PageMovable(page))
8268			continue;
8269
8270		if (!PageLRU(page))
8271			found++;
8272		/*
8273		 * If there are RECLAIMABLE pages, we need to check
8274		 * it.  But now, memory offline itself doesn't call
8275		 * shrink_node_slabs() and it still to be fixed.
8276		 */
8277		/*
8278		 * If the page is not RAM, page_count()should be 0.
8279		 * we don't need more check. This is an _used_ not-movable page.
8280		 *
8281		 * The problematic thing here is PG_reserved pages. PG_reserved
8282		 * is set to both of a memory hole page and a _used_ kernel
8283		 * page at boot.
8284		 */
8285		if (found > count)
8286			goto unmovable;
8287	}
8288	return false;
8289unmovable:
8290	WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE);
8291	if (flags & REPORT_FAILURE)
8292		dump_page(pfn_to_page(pfn + iter), reason);
8293	return true;
8294}
8295
8296#ifdef CONFIG_CONTIG_ALLOC
8297static unsigned long pfn_max_align_down(unsigned long pfn)
 
8298{
8299	return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
8300			     pageblock_nr_pages) - 1);
8301}
8302
8303static unsigned long pfn_max_align_up(unsigned long pfn)
8304{
8305	return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
8306				pageblock_nr_pages));
 
 
 
8307}
8308
8309/* [start, end) must belong to a single zone. */
8310static int __alloc_contig_migrate_range(struct compact_control *cc,
8311					unsigned long start, unsigned long end)
8312{
8313	/* This function is based on compact_zone() from compaction.c. */
8314	unsigned long nr_reclaimed;
8315	unsigned long pfn = start;
8316	unsigned int tries = 0;
8317	int ret = 0;
 
 
 
 
8318
8319	migrate_prep();
8320
8321	while (pfn < end || !list_empty(&cc->migratepages)) {
8322		if (fatal_signal_pending(current)) {
8323			ret = -EINTR;
8324			break;
8325		}
8326
8327		if (list_empty(&cc->migratepages)) {
8328			cc->nr_migratepages = 0;
8329			pfn = isolate_migratepages_range(cc, pfn, end);
8330			if (!pfn) {
8331				ret = -EINTR;
8332				break;
8333			}
8334			tries = 0;
8335		} else if (++tries == 5) {
8336			ret = ret < 0 ? ret : -EBUSY;
8337			break;
8338		}
8339
8340		nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
8341							&cc->migratepages);
8342		cc->nr_migratepages -= nr_reclaimed;
8343
8344		ret = migrate_pages(&cc->migratepages, alloc_migrate_target,
8345				    NULL, 0, cc->mode, MR_CONTIG_RANGE);
 
 
 
 
 
 
 
8346	}
 
 
8347	if (ret < 0) {
 
 
8348		putback_movable_pages(&cc->migratepages);
8349		return ret;
8350	}
8351	return 0;
8352}
8353
8354/**
8355 * alloc_contig_range() -- tries to allocate given range of pages
8356 * @start:	start PFN to allocate
8357 * @end:	one-past-the-last PFN to allocate
8358 * @migratetype:	migratetype of the underlaying pageblocks (either
8359 *			#MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
8360 *			in range must have the same migratetype and it must
8361 *			be either of the two.
8362 * @gfp_mask:	GFP mask to use during compaction
8363 *
8364 * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
8365 * aligned.  The PFN range must belong to a single zone.
8366 *
8367 * The first thing this routine does is attempt to MIGRATE_ISOLATE all
8368 * pageblocks in the range.  Once isolated, the pageblocks should not
8369 * be modified by others.
8370 *
8371 * Return: zero on success or negative error code.  On success all
8372 * pages which PFN is in [start, end) are allocated for the caller and
8373 * need to be freed with free_contig_range().
8374 */
8375int alloc_contig_range(unsigned long start, unsigned long end,
8376		       unsigned migratetype, gfp_t gfp_mask)
8377{
8378	unsigned long outer_start, outer_end;
8379	unsigned int order;
8380	int ret = 0;
8381
8382	struct compact_control cc = {
8383		.nr_migratepages = 0,
8384		.order = -1,
8385		.zone = page_zone(pfn_to_page(start)),
8386		.mode = MIGRATE_SYNC,
8387		.ignore_skip_hint = true,
8388		.no_set_skip_hint = true,
8389		.gfp_mask = current_gfp_context(gfp_mask),
 
8390	};
8391	INIT_LIST_HEAD(&cc.migratepages);
8392
8393	/*
8394	 * What we do here is we mark all pageblocks in range as
8395	 * MIGRATE_ISOLATE.  Because pageblock and max order pages may
8396	 * have different sizes, and due to the way page allocator
8397	 * work, we align the range to biggest of the two pages so
8398	 * that page allocator won't try to merge buddies from
8399	 * different pageblocks and change MIGRATE_ISOLATE to some
8400	 * other migration type.
8401	 *
8402	 * Once the pageblocks are marked as MIGRATE_ISOLATE, we
8403	 * migrate the pages from an unaligned range (ie. pages that
8404	 * we are interested in).  This will put all the pages in
8405	 * range back to page allocator as MIGRATE_ISOLATE.
8406	 *
8407	 * When this is done, we take the pages in range from page
8408	 * allocator removing them from the buddy system.  This way
8409	 * page allocator will never consider using them.
8410	 *
8411	 * This lets us mark the pageblocks back as
8412	 * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
8413	 * aligned range but not in the unaligned, original range are
8414	 * put back to page allocator so that buddy can use them.
8415	 */
8416
8417	ret = start_isolate_page_range(pfn_max_align_down(start),
8418				       pfn_max_align_up(end), migratetype, 0);
8419	if (ret < 0)
8420		return ret;
 
8421
8422	/*
8423	 * In case of -EBUSY, we'd like to know which page causes problem.
8424	 * So, just fall through. test_pages_isolated() has a tracepoint
8425	 * which will report the busy page.
8426	 *
8427	 * It is possible that busy pages could become available before
8428	 * the call to test_pages_isolated, and the range will actually be
8429	 * allocated.  So, if we fall through be sure to clear ret so that
8430	 * -EBUSY is not accidentally used or returned to caller.
8431	 */
8432	ret = __alloc_contig_migrate_range(&cc, start, end);
8433	if (ret && ret != -EBUSY)
8434		goto done;
8435	ret =0;
8436
8437	/*
8438	 * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
8439	 * aligned blocks that are marked as MIGRATE_ISOLATE.  What's
8440	 * more, all pages in [start, end) are free in page allocator.
8441	 * What we are going to do is to allocate all pages from
8442	 * [start, end) (that is remove them from page allocator).
8443	 *
8444	 * The only problem is that pages at the beginning and at the
8445	 * end of interesting range may be not aligned with pages that
8446	 * page allocator holds, ie. they can be part of higher order
8447	 * pages.  Because of this, we reserve the bigger range and
8448	 * once this is done free the pages we are not interested in.
8449	 *
8450	 * We don't have to hold zone->lock here because the pages are
8451	 * isolated thus they won't get removed from buddy.
8452	 */
8453
8454	lru_add_drain_all();
8455
8456	order = 0;
8457	outer_start = start;
8458	while (!PageBuddy(pfn_to_page(outer_start))) {
8459		if (++order >= MAX_ORDER) {
8460			outer_start = start;
8461			break;
8462		}
8463		outer_start &= ~0UL << order;
8464	}
8465
8466	if (outer_start != start) {
8467		order = page_order(pfn_to_page(outer_start));
8468
8469		/*
8470		 * outer_start page could be small order buddy page and
8471		 * it doesn't include start page. Adjust outer_start
8472		 * in this case to report failed page properly
8473		 * on tracepoint in test_pages_isolated()
8474		 */
8475		if (outer_start + (1UL << order) <= start)
8476			outer_start = start;
8477	}
8478
8479	/* Make sure the range is really isolated. */
8480	if (test_pages_isolated(outer_start, end, false)) {
8481		pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n",
8482			__func__, outer_start, end);
8483		ret = -EBUSY;
8484		goto done;
8485	}
8486
8487	/* Grab isolated pages from freelists. */
8488	outer_end = isolate_freepages_range(&cc, outer_start, end);
8489	if (!outer_end) {
8490		ret = -EBUSY;
8491		goto done;
8492	}
8493
8494	/* Free head and tail (if any) */
8495	if (start != outer_start)
8496		free_contig_range(outer_start, start - outer_start);
8497	if (end != outer_end)
8498		free_contig_range(end, outer_end - end);
8499
8500done:
8501	undo_isolate_page_range(pfn_max_align_down(start),
8502				pfn_max_align_up(end), migratetype);
8503	return ret;
8504}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8505#endif /* CONFIG_CONTIG_ALLOC */
8506
8507void free_contig_range(unsigned long pfn, unsigned int nr_pages)
8508{
8509	unsigned int count = 0;
8510
8511	for (; nr_pages--; pfn++) {
8512		struct page *page = pfn_to_page(pfn);
8513
8514		count += page_count(page) != 1;
8515		__free_page(page);
8516	}
8517	WARN(count != 0, "%d pages are still in use!\n", count);
8518}
 
8519
8520/*
8521 * The zone indicated has a new number of managed_pages; batch sizes and percpu
8522 * page high values need to be recalulated.
 
 
 
 
8523 */
8524void __meminit zone_pcp_update(struct zone *zone)
8525{
8526	unsigned cpu;
8527	mutex_lock(&pcp_batch_high_lock);
8528	for_each_possible_cpu(cpu)
8529		pageset_set_high_and_batch(zone,
8530				per_cpu_ptr(zone->pageset, cpu));
 
 
 
 
 
8531	mutex_unlock(&pcp_batch_high_lock);
8532}
8533
8534void zone_pcp_reset(struct zone *zone)
8535{
8536	unsigned long flags;
8537	int cpu;
8538	struct per_cpu_pageset *pset;
8539
8540	/* avoid races with drain_pages()  */
8541	local_irq_save(flags);
8542	if (zone->pageset != &boot_pageset) {
8543		for_each_online_cpu(cpu) {
8544			pset = per_cpu_ptr(zone->pageset, cpu);
8545			drain_zonestat(zone, pset);
 
 
 
 
 
 
8546		}
8547		free_percpu(zone->pageset);
8548		zone->pageset = &boot_pageset;
8549	}
8550	local_irq_restore(flags);
8551}
8552
8553#ifdef CONFIG_MEMORY_HOTREMOVE
8554/*
8555 * All pages in the range must be in a single zone and isolated
8556 * before calling this.
8557 */
8558unsigned long
8559__offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
8560{
 
8561	struct page *page;
8562	struct zone *zone;
8563	unsigned int order, i;
8564	unsigned long pfn;
8565	unsigned long flags;
8566	unsigned long offlined_pages = 0;
8567
8568	/* find the first valid pfn */
8569	for (pfn = start_pfn; pfn < end_pfn; pfn++)
8570		if (pfn_valid(pfn))
8571			break;
8572	if (pfn == end_pfn)
8573		return offlined_pages;
8574
8575	offline_mem_sections(pfn, end_pfn);
8576	zone = page_zone(pfn_to_page(pfn));
8577	spin_lock_irqsave(&zone->lock, flags);
8578	pfn = start_pfn;
8579	while (pfn < end_pfn) {
8580		if (!pfn_valid(pfn)) {
8581			pfn++;
8582			continue;
8583		}
8584		page = pfn_to_page(pfn);
8585		/*
8586		 * The HWPoisoned page may be not in buddy system, and
8587		 * page_count() is not 0.
8588		 */
8589		if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
8590			pfn++;
8591			SetPageReserved(page);
8592			offlined_pages++;
 
 
 
 
 
 
 
 
8593			continue;
8594		}
8595
8596		BUG_ON(page_count(page));
8597		BUG_ON(!PageBuddy(page));
8598		order = page_order(page);
8599		offlined_pages += 1 << order;
8600#ifdef CONFIG_DEBUG_VM
8601		pr_info("remove from free list %lx %d %lx\n",
8602			pfn, 1 << order, end_pfn);
8603#endif
8604		del_page_from_free_area(page, &zone->free_area[order]);
8605		for (i = 0; i < (1 << order); i++)
8606			SetPageReserved((page+i));
8607		pfn += (1 << order);
8608	}
8609	spin_unlock_irqrestore(&zone->lock, flags);
8610
8611	return offlined_pages;
8612}
8613#endif
8614
 
 
 
8615bool is_free_buddy_page(struct page *page)
8616{
8617	struct zone *zone = page_zone(page);
8618	unsigned long pfn = page_to_pfn(page);
8619	unsigned long flags;
8620	unsigned int order;
8621
8622	spin_lock_irqsave(&zone->lock, flags);
8623	for (order = 0; order < MAX_ORDER; order++) {
8624		struct page *page_head = page - (pfn & ((1 << order) - 1));
8625
8626		if (PageBuddy(page_head) && page_order(page_head) >= order)
 
8627			break;
8628	}
8629	spin_unlock_irqrestore(&zone->lock, flags);
8630
8631	return order < MAX_ORDER;
8632}
 
8633
8634#ifdef CONFIG_MEMORY_FAILURE
8635/*
8636 * Set PG_hwpoison flag if a given page is confirmed to be a free page.  This
8637 * test is performed under the zone lock to prevent a race against page
8638 * allocation.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8639 */
8640bool set_hwpoison_free_buddy_page(struct page *page)
8641{
8642	struct zone *zone = page_zone(page);
8643	unsigned long pfn = page_to_pfn(page);
8644	unsigned long flags;
8645	unsigned int order;
8646	bool hwpoisoned = false;
8647
8648	spin_lock_irqsave(&zone->lock, flags);
8649	for (order = 0; order < MAX_ORDER; order++) {
8650		struct page *page_head = page - (pfn & ((1 << order) - 1));
 
8651
8652		if (PageBuddy(page_head) && page_order(page_head) >= order) {
8653			if (!TestSetPageHWPoison(page))
8654				hwpoisoned = true;
 
 
 
 
 
 
 
 
 
 
 
 
8655			break;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8656		}
8657	}
8658	spin_unlock_irqrestore(&zone->lock, flags);
8659
8660	return hwpoisoned;
8661}
8662#endif