linux/mm/page_alloc.c
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   1/*
   2 *  linux/mm/page_alloc.c
   3 *
   4 *  Manages the free list, the system allocates free pages here.
   5 *  Note that kmalloc() lives in slab.c
   6 *
   7 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   8 *  Swap reorganised 29.12.95, Stephen Tweedie
   9 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
  10 *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
  11 *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
  12 *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
  13 *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
  14 *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
  15 */
  16
  17#include <linux/stddef.h>
  18#include <linux/mm.h>
  19#include <linux/swap.h>
  20#include <linux/interrupt.h>
  21#include <linux/pagemap.h>
  22#include <linux/jiffies.h>
  23#include <linux/bootmem.h>
  24#include <linux/memblock.h>
  25#include <linux/compiler.h>
  26#include <linux/kernel.h>
  27#include <linux/kmemcheck.h>
  28#include <linux/module.h>
  29#include <linux/suspend.h>
  30#include <linux/pagevec.h>
  31#include <linux/blkdev.h>
  32#include <linux/slab.h>
  33#include <linux/ratelimit.h>
  34#include <linux/oom.h>
  35#include <linux/notifier.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/stop_machine.h>
  46#include <linux/sort.h>
  47#include <linux/pfn.h>
  48#include <linux/backing-dev.h>
  49#include <linux/fault-inject.h>
  50#include <linux/page-isolation.h>
  51#include <linux/page_cgroup.h>
  52#include <linux/debugobjects.h>
  53#include <linux/kmemleak.h>
  54#include <linux/compaction.h>
  55#include <trace/events/kmem.h>
  56#include <linux/ftrace_event.h>
  57#include <linux/memcontrol.h>
  58#include <linux/prefetch.h>
  59#include <linux/mm_inline.h>
  60#include <linux/migrate.h>
  61#include <linux/page-debug-flags.h>
  62#include <linux/hugetlb.h>
  63#include <linux/sched/rt.h>
  64
  65#include <asm/sections.h>
  66#include <asm/tlbflush.h>
  67#include <asm/div64.h>
  68#include "internal.h"
  69
  70/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
  71static DEFINE_MUTEX(pcp_batch_high_lock);
  72
  73#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
  74DEFINE_PER_CPU(int, numa_node);
  75EXPORT_PER_CPU_SYMBOL(numa_node);
  76#endif
  77
  78#ifdef CONFIG_HAVE_MEMORYLESS_NODES
  79/*
  80 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
  81 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
  82 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
  83 * defined in <linux/topology.h>.
  84 */
  85DEFINE_PER_CPU(int, _numa_mem_);                /* Kernel "local memory" node */
  86EXPORT_PER_CPU_SYMBOL(_numa_mem_);
  87#endif
  88
  89/*
  90 * Array of node states.
  91 */
  92nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
  93        [N_POSSIBLE] = NODE_MASK_ALL,
  94        [N_ONLINE] = { { [0] = 1UL } },
  95#ifndef CONFIG_NUMA
  96        [N_NORMAL_MEMORY] = { { [0] = 1UL } },
  97#ifdef CONFIG_HIGHMEM
  98        [N_HIGH_MEMORY] = { { [0] = 1UL } },
  99#endif
 100#ifdef CONFIG_MOVABLE_NODE
 101        [N_MEMORY] = { { [0] = 1UL } },
 102#endif
 103        [N_CPU] = { { [0] = 1UL } },
 104#endif  /* NUMA */
 105};
 106EXPORT_SYMBOL(node_states);
 107
 108/* Protect totalram_pages and zone->managed_pages */
 109static DEFINE_SPINLOCK(managed_page_count_lock);
 110
 111unsigned long totalram_pages __read_mostly;
 112unsigned long totalreserve_pages __read_mostly;
 113/*
 114 * When calculating the number of globally allowed dirty pages, there
 115 * is a certain number of per-zone reserves that should not be
 116 * considered dirtyable memory.  This is the sum of those reserves
 117 * over all existing zones that contribute dirtyable memory.
 118 */
 119unsigned long dirty_balance_reserve __read_mostly;
 120
 121int percpu_pagelist_fraction;
 122gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
 123
 124#ifdef CONFIG_PM_SLEEP
 125/*
 126 * The following functions are used by the suspend/hibernate code to temporarily
 127 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
 128 * while devices are suspended.  To avoid races with the suspend/hibernate code,
 129 * they should always be called with pm_mutex held (gfp_allowed_mask also should
 130 * only be modified with pm_mutex held, unless the suspend/hibernate code is
 131 * guaranteed not to run in parallel with that modification).
 132 */
 133
 134static gfp_t saved_gfp_mask;
 135
 136void pm_restore_gfp_mask(void)
 137{
 138        WARN_ON(!mutex_is_locked(&pm_mutex));
 139        if (saved_gfp_mask) {
 140                gfp_allowed_mask = saved_gfp_mask;
 141                saved_gfp_mask = 0;
 142        }
 143}
 144
 145void pm_restrict_gfp_mask(void)
 146{
 147        WARN_ON(!mutex_is_locked(&pm_mutex));
 148        WARN_ON(saved_gfp_mask);
 149        saved_gfp_mask = gfp_allowed_mask;
 150        gfp_allowed_mask &= ~GFP_IOFS;
 151}
 152
 153bool pm_suspended_storage(void)
 154{
 155        if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS)
 156                return false;
 157        return true;
 158}
 159#endif /* CONFIG_PM_SLEEP */
 160
 161#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
 162int pageblock_order __read_mostly;
 163#endif
 164
 165static void __free_pages_ok(struct page *page, unsigned int order);
 166
 167/*
 168 * results with 256, 32 in the lowmem_reserve sysctl:
 169 *      1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
 170 *      1G machine -> (16M dma, 784M normal, 224M high)
 171 *      NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
 172 *      HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
 173 *      HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
 174 *
 175 * TBD: should special case ZONE_DMA32 machines here - in those we normally
 176 * don't need any ZONE_NORMAL reservation
 177 */
 178int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
 179#ifdef CONFIG_ZONE_DMA
 180         256,
 181#endif
 182#ifdef CONFIG_ZONE_DMA32
 183         256,
 184#endif
 185#ifdef CONFIG_HIGHMEM
 186         32,
 187#endif
 188         32,
 189};
 190
 191EXPORT_SYMBOL(totalram_pages);
 192
 193static char * const zone_names[MAX_NR_ZONES] = {
 194#ifdef CONFIG_ZONE_DMA
 195         "DMA",
 196#endif
 197#ifdef CONFIG_ZONE_DMA32
 198         "DMA32",
 199#endif
 200         "Normal",
 201#ifdef CONFIG_HIGHMEM
 202         "HighMem",
 203#endif
 204         "Movable",
 205};
 206
 207int min_free_kbytes = 1024;
 208int user_min_free_kbytes;
 209
 210static unsigned long __meminitdata nr_kernel_pages;
 211static unsigned long __meminitdata nr_all_pages;
 212static unsigned long __meminitdata dma_reserve;
 213
 214#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 215static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
 216static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
 217static unsigned long __initdata required_kernelcore;
 218static unsigned long __initdata required_movablecore;
 219static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
 220
 221/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
 222int movable_zone;
 223EXPORT_SYMBOL(movable_zone);
 224#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 225
 226#if MAX_NUMNODES > 1
 227int nr_node_ids __read_mostly = MAX_NUMNODES;
 228int nr_online_nodes __read_mostly = 1;
 229EXPORT_SYMBOL(nr_node_ids);
 230EXPORT_SYMBOL(nr_online_nodes);
 231#endif
 232
 233int page_group_by_mobility_disabled __read_mostly;
 234
 235void set_pageblock_migratetype(struct page *page, int migratetype)
 236{
 237
 238        if (unlikely(page_group_by_mobility_disabled))
 239                migratetype = MIGRATE_UNMOVABLE;
 240
 241        set_pageblock_flags_group(page, (unsigned long)migratetype,
 242                                        PB_migrate, PB_migrate_end);
 243}
 244
 245bool oom_killer_disabled __read_mostly;
 246
 247#ifdef CONFIG_DEBUG_VM
 248static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
 249{
 250        int ret = 0;
 251        unsigned seq;
 252        unsigned long pfn = page_to_pfn(page);
 253        unsigned long sp, start_pfn;
 254
 255        do {
 256                seq = zone_span_seqbegin(zone);
 257                start_pfn = zone->zone_start_pfn;
 258                sp = zone->spanned_pages;
 259                if (!zone_spans_pfn(zone, pfn))
 260                        ret = 1;
 261        } while (zone_span_seqretry(zone, seq));
 262
 263        if (ret)
 264                pr_err("page %lu outside zone [ %lu - %lu ]\n",
 265                        pfn, start_pfn, start_pfn + sp);
 266
 267        return ret;
 268}
 269
 270static int page_is_consistent(struct zone *zone, struct page *page)
 271{
 272        if (!pfn_valid_within(page_to_pfn(page)))
 273                return 0;
 274        if (zone != page_zone(page))
 275                return 0;
 276
 277        return 1;
 278}
 279/*
 280 * Temporary debugging check for pages not lying within a given zone.
 281 */
 282static int bad_range(struct zone *zone, struct page *page)
 283{
 284        if (page_outside_zone_boundaries(zone, page))
 285                return 1;
 286        if (!page_is_consistent(zone, page))
 287                return 1;
 288
 289        return 0;
 290}
 291#else
 292static inline int bad_range(struct zone *zone, struct page *page)
 293{
 294        return 0;
 295}
 296#endif
 297
 298static void bad_page(struct page *page)
 299{
 300        static unsigned long resume;
 301        static unsigned long nr_shown;
 302        static unsigned long nr_unshown;
 303
 304        /* Don't complain about poisoned pages */
 305        if (PageHWPoison(page)) {
 306                page_mapcount_reset(page); /* remove PageBuddy */
 307                return;
 308        }
 309
 310        /*
 311         * Allow a burst of 60 reports, then keep quiet for that minute;
 312         * or allow a steady drip of one report per second.
 313         */
 314        if (nr_shown == 60) {
 315                if (time_before(jiffies, resume)) {
 316                        nr_unshown++;
 317                        goto out;
 318                }
 319                if (nr_unshown) {
 320                        printk(KERN_ALERT
 321                              "BUG: Bad page state: %lu messages suppressed\n",
 322                                nr_unshown);
 323                        nr_unshown = 0;
 324                }
 325                nr_shown = 0;
 326        }
 327        if (nr_shown++ == 0)
 328                resume = jiffies + 60 * HZ;
 329
 330        printk(KERN_ALERT "BUG: Bad page state in process %s  pfn:%05lx\n",
 331                current->comm, page_to_pfn(page));
 332        dump_page(page);
 333
 334        print_modules();
 335        dump_stack();
 336out:
 337        /* Leave bad fields for debug, except PageBuddy could make trouble */
 338        page_mapcount_reset(page); /* remove PageBuddy */
 339        add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 340}
 341
 342/*
 343 * Higher-order pages are called "compound pages".  They are structured thusly:
 344 *
 345 * The first PAGE_SIZE page is called the "head page".
 346 *
 347 * The remaining PAGE_SIZE pages are called "tail pages".
 348 *
 349 * All pages have PG_compound set.  All tail pages have their ->first_page
 350 * pointing at the head page.
 351 *
 352 * The first tail page's ->lru.next holds the address of the compound page's
 353 * put_page() function.  Its ->lru.prev holds the order of allocation.
 354 * This usage means that zero-order pages may not be compound.
 355 */
 356
 357static void free_compound_page(struct page *page)
 358{
 359        __free_pages_ok(page, compound_order(page));
 360}
 361
 362void prep_compound_page(struct page *page, unsigned long order)
 363{
 364        int i;
 365        int nr_pages = 1 << order;
 366
 367        set_compound_page_dtor(page, free_compound_page);
 368        set_compound_order(page, order);
 369        __SetPageHead(page);
 370        for (i = 1; i < nr_pages; i++) {
 371                struct page *p = page + i;
 372                __SetPageTail(p);
 373                set_page_count(p, 0);
 374                p->first_page = page;
 375        }
 376}
 377
 378/* update __split_huge_page_refcount if you change this function */
 379static int destroy_compound_page(struct page *page, unsigned long order)
 380{
 381        int i;
 382        int nr_pages = 1 << order;
 383        int bad = 0;
 384
 385        if (unlikely(compound_order(page) != order)) {
 386                bad_page(page);
 387                bad++;
 388        }
 389
 390        __ClearPageHead(page);
 391
 392        for (i = 1; i < nr_pages; i++) {
 393                struct page *p = page + i;
 394
 395                if (unlikely(!PageTail(p) || (p->first_page != page))) {
 396                        bad_page(page);
 397                        bad++;
 398                }
 399                __ClearPageTail(p);
 400        }
 401
 402        return bad;
 403}
 404
 405static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
 406{
 407        int i;
 408
 409        /*
 410         * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
 411         * and __GFP_HIGHMEM from hard or soft interrupt context.
 412         */
 413        VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
 414        for (i = 0; i < (1 << order); i++)
 415                clear_highpage(page + i);
 416}
 417
 418#ifdef CONFIG_DEBUG_PAGEALLOC
 419unsigned int _debug_guardpage_minorder;
 420
 421static int __init debug_guardpage_minorder_setup(char *buf)
 422{
 423        unsigned long res;
 424
 425        if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
 426                printk(KERN_ERR "Bad debug_guardpage_minorder value\n");
 427                return 0;
 428        }
 429        _debug_guardpage_minorder = res;
 430        printk(KERN_INFO "Setting debug_guardpage_minorder to %lu\n", res);
 431        return 0;
 432}
 433__setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup);
 434
 435static inline void set_page_guard_flag(struct page *page)
 436{
 437        __set_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
 438}
 439
 440static inline void clear_page_guard_flag(struct page *page)
 441{
 442        __clear_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
 443}
 444#else
 445static inline void set_page_guard_flag(struct page *page) { }
 446static inline void clear_page_guard_flag(struct page *page) { }
 447#endif
 448
 449static inline void set_page_order(struct page *page, int order)
 450{
 451        set_page_private(page, order);
 452        __SetPageBuddy(page);
 453}
 454
 455static inline void rmv_page_order(struct page *page)
 456{
 457        __ClearPageBuddy(page);
 458        set_page_private(page, 0);
 459}
 460
 461/*
 462 * Locate the struct page for both the matching buddy in our
 463 * pair (buddy1) and the combined O(n+1) page they form (page).
 464 *
 465 * 1) Any buddy B1 will have an order O twin B2 which satisfies
 466 * the following equation:
 467 *     B2 = B1 ^ (1 << O)
 468 * For example, if the starting buddy (buddy2) is #8 its order
 469 * 1 buddy is #10:
 470 *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
 471 *
 472 * 2) Any buddy B will have an order O+1 parent P which
 473 * satisfies the following equation:
 474 *     P = B & ~(1 << O)
 475 *
 476 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
 477 */
 478static inline unsigned long
 479__find_buddy_index(unsigned long page_idx, unsigned int order)
 480{
 481        return page_idx ^ (1 << order);
 482}
 483
 484/*
 485 * This function checks whether a page is free && is the buddy
 486 * we can do coalesce a page and its buddy if
 487 * (a) the buddy is not in a hole &&
 488 * (b) the buddy is in the buddy system &&
 489 * (c) a page and its buddy have the same order &&
 490 * (d) a page and its buddy are in the same zone.
 491 *
 492 * For recording whether a page is in the buddy system, we set ->_mapcount
 493 * PAGE_BUDDY_MAPCOUNT_VALUE.
 494 * Setting, clearing, and testing _mapcount PAGE_BUDDY_MAPCOUNT_VALUE is
 495 * serialized by zone->lock.
 496 *
 497 * For recording page's order, we use page_private(page).
 498 */
 499static inline int page_is_buddy(struct page *page, struct page *buddy,
 500                                                                int order)
 501{
 502        if (!pfn_valid_within(page_to_pfn(buddy)))
 503                return 0;
 504
 505        if (page_zone_id(page) != page_zone_id(buddy))
 506                return 0;
 507
 508        if (page_is_guard(buddy) && page_order(buddy) == order) {
 509                VM_BUG_ON(page_count(buddy) != 0);
 510                return 1;
 511        }
 512
 513        if (PageBuddy(buddy) && page_order(buddy) == order) {
 514                VM_BUG_ON(page_count(buddy) != 0);
 515                return 1;
 516        }
 517        return 0;
 518}
 519
 520/*
 521 * Freeing function for a buddy system allocator.
 522 *
 523 * The concept of a buddy system is to maintain direct-mapped table
 524 * (containing bit values) for memory blocks of various "orders".
 525 * The bottom level table contains the map for the smallest allocatable
 526 * units of memory (here, pages), and each level above it describes
 527 * pairs of units from the levels below, hence, "buddies".
 528 * At a high level, all that happens here is marking the table entry
 529 * at the bottom level available, and propagating the changes upward
 530 * as necessary, plus some accounting needed to play nicely with other
 531 * parts of the VM system.
 532 * At each level, we keep a list of pages, which are heads of continuous
 533 * free pages of length of (1 << order) and marked with _mapcount
 534 * PAGE_BUDDY_MAPCOUNT_VALUE. Page's order is recorded in page_private(page)
 535 * field.
 536 * So when we are allocating or freeing one, we can derive the state of the
 537 * other.  That is, if we allocate a small block, and both were
 538 * free, the remainder of the region must be split into blocks.
 539 * If a block is freed, and its buddy is also free, then this
 540 * triggers coalescing into a block of larger size.
 541 *
 542 * -- nyc
 543 */
 544
 545static inline void __free_one_page(struct page *page,
 546                struct zone *zone, unsigned int order,
 547                int migratetype)
 548{
 549        unsigned long page_idx;
 550        unsigned long combined_idx;
 551        unsigned long uninitialized_var(buddy_idx);
 552        struct page *buddy;
 553
 554        VM_BUG_ON(!zone_is_initialized(zone));
 555
 556        if (unlikely(PageCompound(page)))
 557                if (unlikely(destroy_compound_page(page, order)))
 558                        return;
 559
 560        VM_BUG_ON(migratetype == -1);
 561
 562        page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
 563
 564        VM_BUG_ON(page_idx & ((1 << order) - 1));
 565        VM_BUG_ON(bad_range(zone, page));
 566
 567        while (order < MAX_ORDER-1) {
 568                buddy_idx = __find_buddy_index(page_idx, order);
 569                buddy = page + (buddy_idx - page_idx);
 570                if (!page_is_buddy(page, buddy, order))
 571                        break;
 572                /*
 573                 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
 574                 * merge with it and move up one order.
 575                 */
 576                if (page_is_guard(buddy)) {
 577                        clear_page_guard_flag(buddy);
 578                        set_page_private(page, 0);
 579                        __mod_zone_freepage_state(zone, 1 << order,
 580                                                  migratetype);
 581                } else {
 582                        list_del(&buddy->lru);
 583                        zone->free_area[order].nr_free--;
 584                        rmv_page_order(buddy);
 585                }
 586                combined_idx = buddy_idx & page_idx;
 587                page = page + (combined_idx - page_idx);
 588                page_idx = combined_idx;
 589                order++;
 590        }
 591        set_page_order(page, order);
 592
 593        /*
 594         * If this is not the largest possible page, check if the buddy
 595         * of the next-highest order is free. If it is, it's possible
 596         * that pages are being freed that will coalesce soon. In case,
 597         * that is happening, add the free page to the tail of the list
 598         * so it's less likely to be used soon and more likely to be merged
 599         * as a higher order page
 600         */
 601        if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
 602                struct page *higher_page, *higher_buddy;
 603                combined_idx = buddy_idx & page_idx;
 604                higher_page = page + (combined_idx - page_idx);
 605                buddy_idx = __find_buddy_index(combined_idx, order + 1);
 606                higher_buddy = higher_page + (buddy_idx - combined_idx);
 607                if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
 608                        list_add_tail(&page->lru,
 609                                &zone->free_area[order].free_list[migratetype]);
 610                        goto out;
 611                }
 612        }
 613
 614        list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
 615out:
 616        zone->free_area[order].nr_free++;
 617}
 618
 619static inline int free_pages_check(struct page *page)
 620{
 621        if (unlikely(page_mapcount(page) |
 622                (page->mapping != NULL)  |
 623                (atomic_read(&page->_count) != 0) |
 624                (page->flags & PAGE_FLAGS_CHECK_AT_FREE) |
 625                (mem_cgroup_bad_page_check(page)))) {
 626                bad_page(page);
 627                return 1;
 628        }
 629        page_nid_reset_last(page);
 630        if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
 631                page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
 632        return 0;
 633}
 634
 635/*
 636 * Frees a number of pages from the PCP lists
 637 * Assumes all pages on list are in same zone, and of same order.
 638 * count is the number of pages to free.
 639 *
 640 * If the zone was previously in an "all pages pinned" state then look to
 641 * see if this freeing clears that state.
 642 *
 643 * And clear the zone's pages_scanned counter, to hold off the "all pages are
 644 * pinned" detection logic.
 645 */
 646static void free_pcppages_bulk(struct zone *zone, int count,
 647                                        struct per_cpu_pages *pcp)
 648{
 649        int migratetype = 0;
 650        int batch_free = 0;
 651        int to_free = count;
 652
 653        spin_lock(&zone->lock);
 654        zone->pages_scanned = 0;
 655
 656        while (to_free) {
 657                struct page *page;
 658                struct list_head *list;
 659
 660                /*
 661                 * Remove pages from lists in a round-robin fashion. A
 662                 * batch_free count is maintained that is incremented when an
 663                 * empty list is encountered.  This is so more pages are freed
 664                 * off fuller lists instead of spinning excessively around empty
 665                 * lists
 666                 */
 667                do {
 668                        batch_free++;
 669                        if (++migratetype == MIGRATE_PCPTYPES)
 670                                migratetype = 0;
 671                        list = &pcp->lists[migratetype];
 672                } while (list_empty(list));
 673
 674                /* This is the only non-empty list. Free them all. */
 675                if (batch_free == MIGRATE_PCPTYPES)
 676                        batch_free = to_free;
 677
 678                do {
 679                        int mt; /* migratetype of the to-be-freed page */
 680
 681                        page = list_entry(list->prev, struct page, lru);
 682                        /* must delete as __free_one_page list manipulates */
 683                        list_del(&page->lru);
 684                        mt = get_freepage_migratetype(page);
 685                        /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
 686                        __free_one_page(page, zone, 0, mt);
 687                        trace_mm_page_pcpu_drain(page, 0, mt);
 688                        if (likely(!is_migrate_isolate_page(page))) {
 689                                __mod_zone_page_state(zone, NR_FREE_PAGES, 1);
 690                                if (is_migrate_cma(mt))
 691                                        __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
 692                        }
 693                } while (--to_free && --batch_free && !list_empty(list));
 694        }
 695        spin_unlock(&zone->lock);
 696}
 697
 698static void free_one_page(struct zone *zone, struct page *page, int order,
 699                                int migratetype)
 700{
 701        spin_lock(&zone->lock);
 702        zone->pages_scanned = 0;
 703
 704        __free_one_page(page, zone, order, migratetype);
 705        if (unlikely(!is_migrate_isolate(migratetype)))
 706                __mod_zone_freepage_state(zone, 1 << order, migratetype);
 707        spin_unlock(&zone->lock);
 708}
 709
 710static bool free_pages_prepare(struct page *page, unsigned int order)
 711{
 712        int i;
 713        int bad = 0;
 714
 715        trace_mm_page_free(page, order);
 716        kmemcheck_free_shadow(page, order);
 717
 718        if (PageAnon(page))
 719                page->mapping = NULL;
 720        for (i = 0; i < (1 << order); i++)
 721                bad += free_pages_check(page + i);
 722        if (bad)
 723                return false;
 724
 725        if (!PageHighMem(page)) {
 726                debug_check_no_locks_freed(page_address(page),
 727                                           PAGE_SIZE << order);
 728                debug_check_no_obj_freed(page_address(page),
 729                                           PAGE_SIZE << order);
 730        }
 731        arch_free_page(page, order);
 732        kernel_map_pages(page, 1 << order, 0);
 733
 734        return true;
 735}
 736
 737static void __free_pages_ok(struct page *page, unsigned int order)
 738{
 739        unsigned long flags;
 740        int migratetype;
 741
 742        if (!free_pages_prepare(page, order))
 743                return;
 744
 745        local_irq_save(flags);
 746        __count_vm_events(PGFREE, 1 << order);
 747        migratetype = get_pageblock_migratetype(page);
 748        set_freepage_migratetype(page, migratetype);
 749        free_one_page(page_zone(page), page, order, migratetype);
 750        local_irq_restore(flags);
 751}
 752
 753void __init __free_pages_bootmem(struct page *page, unsigned int order)
 754{
 755        unsigned int nr_pages = 1 << order;
 756        struct page *p = page;
 757        unsigned int loop;
 758
 759        prefetchw(p);
 760        for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
 761                prefetchw(p + 1);
 762                __ClearPageReserved(p);
 763                set_page_count(p, 0);
 764        }
 765        __ClearPageReserved(p);
 766        set_page_count(p, 0);
 767
 768        page_zone(page)->managed_pages += nr_pages;
 769        set_page_refcounted(page);
 770        __free_pages(page, order);
 771}
 772
 773#ifdef CONFIG_CMA
 774/* Free whole pageblock and set its migration type to MIGRATE_CMA. */
 775void __init init_cma_reserved_pageblock(struct page *page)
 776{
 777        unsigned i = pageblock_nr_pages;
 778        struct page *p = page;
 779
 780        do {
 781                __ClearPageReserved(p);
 782                set_page_count(p, 0);
 783        } while (++p, --i);
 784
 785        set_page_refcounted(page);
 786        set_pageblock_migratetype(page, MIGRATE_CMA);
 787        __free_pages(page, pageblock_order);
 788        adjust_managed_page_count(page, pageblock_nr_pages);
 789}
 790#endif
 791
 792/*
 793 * The order of subdivision here is critical for the IO subsystem.
 794 * Please do not alter this order without good reasons and regression
 795 * testing. Specifically, as large blocks of memory are subdivided,
 796 * the order in which smaller blocks are delivered depends on the order
 797 * they're subdivided in this function. This is the primary factor
 798 * influencing the order in which pages are delivered to the IO
 799 * subsystem according to empirical testing, and this is also justified
 800 * by considering the behavior of a buddy system containing a single
 801 * large block of memory acted on by a series of small allocations.
 802 * This behavior is a critical factor in sglist merging's success.
 803 *
 804 * -- nyc
 805 */
 806static inline void expand(struct zone *zone, struct page *page,
 807        int low, int high, struct free_area *area,
 808        int migratetype)
 809{
 810        unsigned long size = 1 << high;
 811
 812        while (high > low) {
 813                area--;
 814                high--;
 815                size >>= 1;
 816                VM_BUG_ON(bad_range(zone, &page[size]));
 817
 818#ifdef CONFIG_DEBUG_PAGEALLOC
 819                if (high < debug_guardpage_minorder()) {
 820                        /*
 821                         * Mark as guard pages (or page), that will allow to
 822                         * merge back to allocator when buddy will be freed.
 823                         * Corresponding page table entries will not be touched,
 824                         * pages will stay not present in virtual address space
 825                         */
 826                        INIT_LIST_HEAD(&page[size].lru);
 827                        set_page_guard_flag(&page[size]);
 828                        set_page_private(&page[size], high);
 829                        /* Guard pages are not available for any usage */
 830                        __mod_zone_freepage_state(zone, -(1 << high),
 831                                                  migratetype);
 832                        continue;
 833                }
 834#endif
 835                list_add(&page[size].lru, &area->free_list[migratetype]);
 836                area->nr_free++;
 837                set_page_order(&page[size], high);
 838        }
 839}
 840
 841/*
 842 * This page is about to be returned from the page allocator
 843 */
 844static inline int check_new_page(struct page *page)
 845{
 846        if (unlikely(page_mapcount(page) |
 847                (page->mapping != NULL)  |
 848                (atomic_read(&page->_count) != 0)  |
 849                (page->flags & PAGE_FLAGS_CHECK_AT_PREP) |
 850                (mem_cgroup_bad_page_check(page)))) {
 851                bad_page(page);
 852                return 1;
 853        }
 854        return 0;
 855}
 856
 857static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
 858{
 859        int i;
 860
 861        for (i = 0; i < (1 << order); i++) {
 862                struct page *p = page + i;
 863                if (unlikely(check_new_page(p)))
 864                        return 1;
 865        }
 866
 867        set_page_private(page, 0);
 868        set_page_refcounted(page);
 869
 870        arch_alloc_page(page, order);
 871        kernel_map_pages(page, 1 << order, 1);
 872
 873        if (gfp_flags & __GFP_ZERO)
 874                prep_zero_page(page, order, gfp_flags);
 875
 876        if (order && (gfp_flags & __GFP_COMP))
 877                prep_compound_page(page, order);
 878
 879        return 0;
 880}
 881
 882/*
 883 * Go through the free lists for the given migratetype and remove
 884 * the smallest available page from the freelists
 885 */
 886static inline
 887struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
 888                                                int migratetype)
 889{
 890        unsigned int current_order;
 891        struct free_area *area;
 892        struct page *page;
 893
 894        /* Find a page of the appropriate size in the preferred list */
 895        for (current_order = order; current_order < MAX_ORDER; ++current_order) {
 896                area = &(zone->free_area[current_order]);
 897                if (list_empty(&area->free_list[migratetype]))
 898                        continue;
 899
 900                page = list_entry(area->free_list[migratetype].next,
 901                                                        struct page, lru);
 902                list_del(&page->lru);
 903                rmv_page_order(page);
 904                area->nr_free--;
 905                expand(zone, page, order, current_order, area, migratetype);
 906                return page;
 907        }
 908
 909        return NULL;
 910}
 911
 912
 913/*
 914 * This array describes the order lists are fallen back to when
 915 * the free lists for the desirable migrate type are depleted
 916 */
 917static int fallbacks[MIGRATE_TYPES][4] = {
 918        [MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,     MIGRATE_RESERVE },
 919        [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,     MIGRATE_RESERVE },
 920#ifdef CONFIG_CMA
 921        [MIGRATE_MOVABLE]     = { MIGRATE_CMA,         MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
 922        [MIGRATE_CMA]         = { MIGRATE_RESERVE }, /* Never used */
 923#else
 924        [MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE,   MIGRATE_RESERVE },
 925#endif
 926        [MIGRATE_RESERVE]     = { MIGRATE_RESERVE }, /* Never used */
 927#ifdef CONFIG_MEMORY_ISOLATION
 928        [MIGRATE_ISOLATE]     = { MIGRATE_RESERVE }, /* Never used */
 929#endif
 930};
 931
 932/*
 933 * Move the free pages in a range to the free lists of the requested type.
 934 * Note that start_page and end_pages are not aligned on a pageblock
 935 * boundary. If alignment is required, use move_freepages_block()
 936 */
 937int move_freepages(struct zone *zone,
 938                          struct page *start_page, struct page *end_page,
 939                          int migratetype)
 940{
 941        struct page *page;
 942        unsigned long order;
 943        int pages_moved = 0;
 944
 945#ifndef CONFIG_HOLES_IN_ZONE
 946        /*
 947         * page_zone is not safe to call in this context when
 948         * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
 949         * anyway as we check zone boundaries in move_freepages_block().
 950         * Remove at a later date when no bug reports exist related to
 951         * grouping pages by mobility
 952         */
 953        BUG_ON(page_zone(start_page) != page_zone(end_page));
 954#endif
 955
 956        for (page = start_page; page <= end_page;) {
 957                /* Make sure we are not inadvertently changing nodes */
 958                VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
 959
 960                if (!pfn_valid_within(page_to_pfn(page))) {
 961                        page++;
 962                        continue;
 963                }
 964
 965                if (!PageBuddy(page)) {
 966                        page++;
 967                        continue;
 968                }
 969
 970                order = page_order(page);
 971                list_move(&page->lru,
 972                          &zone->free_area[order].free_list[migratetype]);
 973                set_freepage_migratetype(page, migratetype);
 974                page += 1 << order;
 975                pages_moved += 1 << order;
 976        }
 977
 978        return pages_moved;
 979}
 980
 981int move_freepages_block(struct zone *zone, struct page *page,
 982                                int migratetype)
 983{
 984        unsigned long start_pfn, end_pfn;
 985        struct page *start_page, *end_page;
 986
 987        start_pfn = page_to_pfn(page);
 988        start_pfn = start_pfn & ~(pageblock_nr_pages-1);
 989        start_page = pfn_to_page(start_pfn);
 990        end_page = start_page + pageblock_nr_pages - 1;
 991        end_pfn = start_pfn + pageblock_nr_pages - 1;
 992
 993        /* Do not cross zone boundaries */
 994        if (!zone_spans_pfn(zone, start_pfn))
 995                start_page = page;
 996        if (!zone_spans_pfn(zone, end_pfn))
 997                return 0;
 998
 999        return move_freepages(zone, start_page, end_page, migratetype);
1000}
1001
1002static void change_pageblock_range(struct page *pageblock_page,
1003                                        int start_order, int migratetype)
1004{
1005        int nr_pageblocks = 1 << (start_order - pageblock_order);
1006
1007        while (nr_pageblocks--) {
1008                set_pageblock_migratetype(pageblock_page, migratetype);
1009                pageblock_page += pageblock_nr_pages;
1010        }
1011}
1012
1013/*
1014 * If breaking a large block of pages, move all free pages to the preferred
1015 * allocation list. If falling back for a reclaimable kernel allocation, be
1016 * more aggressive about taking ownership of free pages.
1017 *
1018 * On the other hand, never change migration type of MIGRATE_CMA pageblocks
1019 * nor move CMA pages to different free lists. We don't want unmovable pages
1020 * to be allocated from MIGRATE_CMA areas.
1021 *
1022 * Returns the new migratetype of the pageblock (or the same old migratetype
1023 * if it was unchanged).
1024 */
1025static int try_to_steal_freepages(struct zone *zone, struct page *page,
1026                                  int start_type, int fallback_type)
1027{
1028        int current_order = page_order(page);
1029
1030        if (is_migrate_cma(fallback_type))
1031                return fallback_type;
1032
1033        /* Take ownership for orders >= pageblock_order */
1034        if (current_order >= pageblock_order) {
1035                change_pageblock_range(page, current_order, start_type);
1036                return start_type;
1037        }
1038
1039        if (current_order >= pageblock_order / 2 ||
1040            start_type == MIGRATE_RECLAIMABLE ||
1041            page_group_by_mobility_disabled) {
1042                int pages;
1043
1044                pages = move_freepages_block(zone, page, start_type);
1045
1046                /* Claim the whole block if over half of it is free */
1047                if (pages >= (1 << (pageblock_order-1)) ||
1048                                page_group_by_mobility_disabled) {
1049
1050                        set_pageblock_migratetype(page, start_type);
1051                        return start_type;
1052                }
1053
1054        }
1055
1056        return fallback_type;
1057}
1058
1059/* Remove an element from the buddy allocator from the fallback list */
1060static inline struct page *
1061__rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
1062{
1063        struct free_area *area;
1064        int current_order;
1065        struct page *page;
1066        int migratetype, new_type, i;
1067
1068        /* Find the largest possible block of pages in the other list */
1069        for (current_order = MAX_ORDER-1; current_order >= order;
1070                                                --current_order) {
1071                for (i = 0;; i++) {
1072                        migratetype = fallbacks[start_migratetype][i];
1073
1074                        /* MIGRATE_RESERVE handled later if necessary */
1075                        if (migratetype == MIGRATE_RESERVE)
1076                                break;
1077
1078                        area = &(zone->free_area[current_order]);
1079                        if (list_empty(&area->free_list[migratetype]))
1080                                continue;
1081
1082                        page = list_entry(area->free_list[migratetype].next,
1083                                        struct page, lru);
1084                        area->nr_free--;
1085
1086                        new_type = try_to_steal_freepages(zone, page,
1087                                                          start_migratetype,
1088                                                          migratetype);
1089
1090                        /* Remove the page from the freelists */
1091                        list_del(&page->lru);
1092                        rmv_page_order(page);
1093
1094                        /*
1095                         * Borrow the excess buddy pages as well, irrespective
1096                         * of whether we stole freepages, or took ownership of
1097                         * the pageblock or not.
1098                         *
1099                         * Exception: When borrowing from MIGRATE_CMA, release
1100                         * the excess buddy pages to CMA itself.
1101                         */
1102                        expand(zone, page, order, current_order, area,
1103                               is_migrate_cma(migratetype)
1104                             ? migratetype : start_migratetype);
1105
1106                        trace_mm_page_alloc_extfrag(page, order,
1107                                current_order, start_migratetype, migratetype,
1108                                new_type == start_migratetype);
1109
1110                        return page;
1111                }
1112        }
1113
1114        return NULL;
1115}
1116
1117/*
1118 * Do the hard work of removing an element from the buddy allocator.
1119 * Call me with the zone->lock already held.
1120 */
1121static struct page *__rmqueue(struct zone *zone, unsigned int order,
1122                                                int migratetype)
1123{
1124        struct page *page;
1125
1126retry_reserve:
1127        page = __rmqueue_smallest(zone, order, migratetype);
1128
1129        if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
1130                page = __rmqueue_fallback(zone, order, migratetype);
1131
1132                /*
1133                 * Use MIGRATE_RESERVE rather than fail an allocation. goto
1134                 * is used because __rmqueue_smallest is an inline function
1135                 * and we want just one call site
1136                 */
1137                if (!page) {
1138                        migratetype = MIGRATE_RESERVE;
1139                        goto retry_reserve;
1140                }
1141        }
1142
1143        trace_mm_page_alloc_zone_locked(page, order, migratetype);
1144        return page;
1145}
1146
1147/*
1148 * Obtain a specified number of elements from the buddy allocator, all under
1149 * a single hold of the lock, for efficiency.  Add them to the supplied list.
1150 * Returns the number of new pages which were placed at *list.
1151 */
1152static int rmqueue_bulk(struct zone *zone, unsigned int order,
1153                        unsigned long count, struct list_head *list,
1154                        int migratetype, int cold)
1155{
1156        int mt = migratetype, i;
1157
1158        spin_lock(&zone->lock);
1159        for (i = 0; i < count; ++i) {
1160                struct page *page = __rmqueue(zone, order, migratetype);
1161                if (unlikely(page == NULL))
1162                        break;
1163
1164                /*
1165                 * Split buddy pages returned by expand() are received here
1166                 * in physical page order. The page is added to the callers and
1167                 * list and the list head then moves forward. From the callers
1168                 * perspective, the linked list is ordered by page number in
1169                 * some conditions. This is useful for IO devices that can
1170                 * merge IO requests if the physical pages are ordered
1171                 * properly.
1172                 */
1173                if (likely(cold == 0))
1174                        list_add(&page->lru, list);
1175                else
1176                        list_add_tail(&page->lru, list);
1177                if (IS_ENABLED(CONFIG_CMA)) {
1178                        mt = get_pageblock_migratetype(page);
1179                        if (!is_migrate_cma(mt) && !is_migrate_isolate(mt))
1180                                mt = migratetype;
1181                }
1182                set_freepage_migratetype(page, mt);
1183                list = &page->lru;
1184                if (is_migrate_cma(mt))
1185                        __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
1186                                              -(1 << order));
1187        }
1188        __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
1189        spin_unlock(&zone->lock);
1190        return i;
1191}
1192
1193#ifdef CONFIG_NUMA
1194/*
1195 * Called from the vmstat counter updater to drain pagesets of this
1196 * currently executing processor on remote nodes after they have
1197 * expired.
1198 *
1199 * Note that this function must be called with the thread pinned to
1200 * a single processor.
1201 */
1202void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
1203{
1204        unsigned long flags;
1205        int to_drain;
1206        unsigned long batch;
1207
1208        local_irq_save(flags);
1209        batch = ACCESS_ONCE(pcp->batch);
1210        if (pcp->count >= batch)
1211                to_drain = batch;
1212        else
1213                to_drain = pcp->count;
1214        if (to_drain > 0) {
1215                free_pcppages_bulk(zone, to_drain, pcp);
1216                pcp->count -= to_drain;
1217        }
1218        local_irq_restore(flags);
1219}
1220#endif
1221
1222/*
1223 * Drain pages of the indicated processor.
1224 *
1225 * The processor must either be the current processor and the
1226 * thread pinned to the current processor or a processor that
1227 * is not online.
1228 */
1229static void drain_pages(unsigned int cpu)
1230{
1231        unsigned long flags;
1232        struct zone *zone;
1233
1234        for_each_populated_zone(zone) {
1235                struct per_cpu_pageset *pset;
1236                struct per_cpu_pages *pcp;
1237
1238                local_irq_save(flags);
1239                pset = per_cpu_ptr(zone->pageset, cpu);
1240
1241                pcp = &pset->pcp;
1242                if (pcp->count) {
1243                        free_pcppages_bulk(zone, pcp->count, pcp);
1244                        pcp->count = 0;
1245                }
1246                local_irq_restore(flags);
1247        }
1248}
1249
1250/*
1251 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
1252 */
1253void drain_local_pages(void *arg)
1254{
1255        drain_pages(smp_processor_id());
1256}
1257
1258/*
1259 * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
1260 *
1261 * Note that this code is protected against sending an IPI to an offline
1262 * CPU but does not guarantee sending an IPI to newly hotplugged CPUs:
1263 * on_each_cpu_mask() blocks hotplug and won't talk to offlined CPUs but
1264 * nothing keeps CPUs from showing up after we populated the cpumask and
1265 * before the call to on_each_cpu_mask().
1266 */
1267void drain_all_pages(void)
1268{
1269        int cpu;
1270        struct per_cpu_pageset *pcp;
1271        struct zone *zone;
1272
1273        /*
1274         * Allocate in the BSS so we wont require allocation in
1275         * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
1276         */
1277        static cpumask_t cpus_with_pcps;
1278
1279        /*
1280         * We don't care about racing with CPU hotplug event
1281         * as offline notification will cause the notified
1282         * cpu to drain that CPU pcps and on_each_cpu_mask
1283         * disables preemption as part of its processing
1284         */
1285        for_each_online_cpu(cpu) {
1286                bool has_pcps = false;
1287                for_each_populated_zone(zone) {
1288                        pcp = per_cpu_ptr(zone->pageset, cpu);
1289                        if (pcp->pcp.count) {
1290                                has_pcps = true;
1291                                break;
1292                        }
1293                }
1294                if (has_pcps)
1295                        cpumask_set_cpu(cpu, &cpus_with_pcps);
1296                else
1297                        cpumask_clear_cpu(cpu, &cpus_with_pcps);
1298        }
1299        on_each_cpu_mask(&cpus_with_pcps, drain_local_pages, NULL, 1);
1300}
1301
1302#ifdef CONFIG_HIBERNATION
1303
1304void mark_free_pages(struct zone *zone)
1305{
1306        unsigned long pfn, max_zone_pfn;
1307        unsigned long flags;
1308        int order, t;
1309        struct list_head *curr;
1310
1311        if (zone_is_empty(zone))
1312                return;
1313
1314        spin_lock_irqsave(&zone->lock, flags);
1315
1316        max_zone_pfn = zone_end_pfn(zone);
1317        for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1318                if (pfn_valid(pfn)) {
1319                        struct page *page = pfn_to_page(pfn);
1320
1321                        if (!swsusp_page_is_forbidden(page))
1322                                swsusp_unset_page_free(page);
1323                }
1324
1325        for_each_migratetype_order(order, t) {
1326                list_for_each(curr, &zone->free_area[order].free_list[t]) {
1327                        unsigned long i;
1328
1329                        pfn = page_to_pfn(list_entry(curr, struct page, lru));
1330                        for (i = 0; i < (1UL << order); i++)
1331                                swsusp_set_page_free(pfn_to_page(pfn + i));
1332                }
1333        }
1334        spin_unlock_irqrestore(&zone->lock, flags);
1335}
1336#endif /* CONFIG_PM */
1337
1338/*
1339 * Free a 0-order page
1340 * cold == 1 ? free a cold page : free a hot page
1341 */
1342void free_hot_cold_page(struct page *page, int cold)
1343{
1344        struct zone *zone = page_zone(page);
1345        struct per_cpu_pages *pcp;
1346        unsigned long flags;
1347        int migratetype;
1348
1349        if (!free_pages_prepare(page, 0))
1350                return;
1351
1352        migratetype = get_pageblock_migratetype(page);
1353        set_freepage_migratetype(page, migratetype);
1354        local_irq_save(flags);
1355        __count_vm_event(PGFREE);
1356
1357        /*
1358         * We only track unmovable, reclaimable and movable on pcp lists.
1359         * Free ISOLATE pages back to the allocator because they are being
1360         * offlined but treat RESERVE as movable pages so we can get those
1361         * areas back if necessary. Otherwise, we may have to free
1362         * excessively into the page allocator
1363         */
1364        if (migratetype >= MIGRATE_PCPTYPES) {
1365                if (unlikely(is_migrate_isolate(migratetype))) {
1366                        free_one_page(zone, page, 0, migratetype);
1367                        goto out;
1368                }
1369                migratetype = MIGRATE_MOVABLE;
1370        }
1371
1372        pcp = &this_cpu_ptr(zone->pageset)->pcp;
1373        if (cold)
1374                list_add_tail(&page->lru, &pcp->lists[migratetype]);
1375        else
1376                list_add(&page->lru, &pcp->lists[migratetype]);
1377        pcp->count++;
1378        if (pcp->count >= pcp->high) {
1379                unsigned long batch = ACCESS_ONCE(pcp->batch);
1380                free_pcppages_bulk(zone, batch, pcp);
1381                pcp->count -= batch;
1382        }
1383
1384out:
1385        local_irq_restore(flags);
1386}
1387
1388/*
1389 * Free a list of 0-order pages
1390 */
1391void free_hot_cold_page_list(struct list_head *list, int cold)
1392{
1393        struct page *page, *next;
1394
1395        list_for_each_entry_safe(page, next, list, lru) {
1396                trace_mm_page_free_batched(page, cold);
1397                free_hot_cold_page(page, cold);
1398        }
1399}
1400
1401/*
1402 * split_page takes a non-compound higher-order page, and splits it into
1403 * n (1<<order) sub-pages: page[0..n]
1404 * Each sub-page must be freed individually.
1405 *
1406 * Note: this is probably too low level an operation for use in drivers.
1407 * Please consult with lkml before using this in your driver.
1408 */
1409void split_page(struct page *page, unsigned int order)
1410{
1411        int i;
1412
1413        VM_BUG_ON(PageCompound(page));
1414        VM_BUG_ON(!page_count(page));
1415
1416#ifdef CONFIG_KMEMCHECK
1417        /*
1418         * Split shadow pages too, because free(page[0]) would
1419         * otherwise free the whole shadow.
1420         */
1421        if (kmemcheck_page_is_tracked(page))
1422                split_page(virt_to_page(page[0].shadow), order);
1423#endif
1424
1425        for (i = 1; i < (1 << order); i++)
1426                set_page_refcounted(page + i);
1427}
1428EXPORT_SYMBOL_GPL(split_page);
1429
1430static int __isolate_free_page(struct page *page, unsigned int order)
1431{
1432        unsigned long watermark;
1433        struct zone *zone;
1434        int mt;
1435
1436        BUG_ON(!PageBuddy(page));
1437
1438        zone = page_zone(page);
1439        mt = get_pageblock_migratetype(page);
1440
1441        if (!is_migrate_isolate(mt)) {
1442                /* Obey watermarks as if the page was being allocated */
1443                watermark = low_wmark_pages(zone) + (1 << order);
1444                if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
1445                        return 0;
1446
1447                __mod_zone_freepage_state(zone, -(1UL << order), mt);
1448        }
1449
1450        /* Remove page from free list */
1451        list_del(&page->lru);
1452        zone->free_area[order].nr_free--;
1453        rmv_page_order(page);
1454
1455        /* Set the pageblock if the isolated page is at least a pageblock */
1456        if (order >= pageblock_order - 1) {
1457                struct page *endpage = page + (1 << order) - 1;
1458                for (; page < endpage; page += pageblock_nr_pages) {
1459                        int mt = get_pageblock_migratetype(page);
1460                        if (!is_migrate_isolate(mt) && !is_migrate_cma(mt))
1461                                set_pageblock_migratetype(page,
1462                                                          MIGRATE_MOVABLE);
1463                }
1464        }
1465
1466        return 1UL << order;
1467}
1468
1469/*
1470 * Similar to split_page except the page is already free. As this is only
1471 * being used for migration, the migratetype of the block also changes.
1472 * As this is called with interrupts disabled, the caller is responsible
1473 * for calling arch_alloc_page() and kernel_map_page() after interrupts
1474 * are enabled.
1475 *
1476 * Note: this is probably too low level an operation for use in drivers.
1477 * Please consult with lkml before using this in your driver.
1478 */
1479int split_free_page(struct page *page)
1480{
1481        unsigned int order;
1482        int nr_pages;
1483
1484        order = page_order(page);
1485
1486        nr_pages = __isolate_free_page(page, order);
1487        if (!nr_pages)
1488                return 0;
1489
1490        /* Split into individual pages */
1491        set_page_refcounted(page);
1492        split_page(page, order);
1493        return nr_pages;
1494}
1495
1496/*
1497 * Really, prep_compound_page() should be called from __rmqueue_bulk().  But
1498 * we cheat by calling it from here, in the order > 0 path.  Saves a branch
1499 * or two.
1500 */
1501static inline
1502struct page *buffered_rmqueue(struct zone *preferred_zone,
1503                        struct zone *zone, int order, gfp_t gfp_flags,
1504                        int migratetype)
1505{
1506        unsigned long flags;
1507        struct page *page;
1508        int cold = !!(gfp_flags & __GFP_COLD);
1509
1510again:
1511        if (likely(order == 0)) {
1512                struct per_cpu_pages *pcp;
1513                struct list_head *list;
1514
1515                local_irq_save(flags);
1516                pcp = &this_cpu_ptr(zone->pageset)->pcp;
1517                list = &pcp->lists[migratetype];
1518                if (list_empty(list)) {
1519                        pcp->count += rmqueue_bulk(zone, 0,
1520                                        pcp->batch, list,
1521                                        migratetype, cold);
1522                        if (unlikely(list_empty(list)))
1523                                goto failed;
1524                }
1525
1526                if (cold)
1527                        page = list_entry(list->prev, struct page, lru);
1528                else
1529                        page = list_entry(list->next, struct page, lru);
1530
1531                list_del(&page->lru);
1532                pcp->count--;
1533        } else {
1534                if (unlikely(gfp_flags & __GFP_NOFAIL)) {
1535                        /*
1536                         * __GFP_NOFAIL is not to be used in new code.
1537                         *
1538                         * All __GFP_NOFAIL callers should be fixed so that they
1539                         * properly detect and handle allocation failures.
1540                         *
1541                         * We most definitely don't want callers attempting to
1542                         * allocate greater than order-1 page units with
1543                         * __GFP_NOFAIL.
1544                         */
1545                        WARN_ON_ONCE(order > 1);
1546                }
1547                spin_lock_irqsave(&zone->lock, flags);
1548                page = __rmqueue(zone, order, migratetype);
1549                spin_unlock(&zone->lock);
1550                if (!page)
1551                        goto failed;
1552                __mod_zone_freepage_state(zone, -(1 << order),
1553                                          get_pageblock_migratetype(page));
1554        }
1555
1556        __mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
1557        __count_zone_vm_events(PGALLOC, zone, 1 << order);
1558        zone_statistics(preferred_zone, zone, gfp_flags);
1559        local_irq_restore(flags);
1560
1561        VM_BUG_ON(bad_range(zone, page));
1562        if (prep_new_page(page, order, gfp_flags))
1563                goto again;
1564        return page;
1565
1566failed:
1567        local_irq_restore(flags);
1568        return NULL;
1569}
1570
1571#ifdef CONFIG_FAIL_PAGE_ALLOC
1572
1573static struct {
1574        struct fault_attr attr;
1575
1576        u32 ignore_gfp_highmem;
1577        u32 ignore_gfp_wait;
1578        u32 min_order;
1579} fail_page_alloc = {
1580        .attr = FAULT_ATTR_INITIALIZER,
1581        .ignore_gfp_wait = 1,
1582        .ignore_gfp_highmem = 1,
1583        .min_order = 1,
1584};
1585
1586static int __init setup_fail_page_alloc(char *str)
1587{
1588        return setup_fault_attr(&fail_page_alloc.attr, str);
1589}
1590__setup("fail_page_alloc=", setup_fail_page_alloc);
1591
1592static bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1593{
1594        if (order < fail_page_alloc.min_order)
1595                return false;
1596        if (gfp_mask & __GFP_NOFAIL)
1597                return false;
1598        if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1599                return false;
1600        if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1601                return false;
1602
1603        return should_fail(&fail_page_alloc.attr, 1 << order);
1604}
1605
1606#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1607
1608static int __init fail_page_alloc_debugfs(void)
1609{
1610        umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1611        struct dentry *dir;
1612
1613        dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
1614                                        &fail_page_alloc.attr);
1615        if (IS_ERR(dir))
1616                return PTR_ERR(dir);
1617
1618        if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
1619                                &fail_page_alloc.ignore_gfp_wait))
1620                goto fail;
1621        if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1622                                &fail_page_alloc.ignore_gfp_highmem))
1623                goto fail;
1624        if (!debugfs_create_u32("min-order", mode, dir,
1625                                &fail_page_alloc.min_order))
1626                goto fail;
1627
1628        return 0;
1629fail:
1630        debugfs_remove_recursive(dir);
1631
1632        return -ENOMEM;
1633}
1634
1635late_initcall(fail_page_alloc_debugfs);
1636
1637#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1638
1639#else /* CONFIG_FAIL_PAGE_ALLOC */
1640
1641static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1642{
1643        return false;
1644}
1645
1646#endif /* CONFIG_FAIL_PAGE_ALLOC */
1647
1648/*
1649 * Return true if free pages are above 'mark'. This takes into account the order
1650 * of the allocation.
1651 */
1652static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1653                      int classzone_idx, int alloc_flags, long free_pages)
1654{
1655        /* free_pages my go negative - that's OK */
1656        long min = mark;
1657        long lowmem_reserve = z->lowmem_reserve[classzone_idx];
1658        int o;
1659        long free_cma = 0;
1660
1661        free_pages -= (1 << order) - 1;
1662        if (alloc_flags & ALLOC_HIGH)
1663                min -= min / 2;
1664        if (alloc_flags & ALLOC_HARDER)
1665                min -= min / 4;
1666#ifdef CONFIG_CMA
1667        /* If allocation can't use CMA areas don't use free CMA pages */
1668        if (!(alloc_flags & ALLOC_CMA))
1669                free_cma = zone_page_state(z, NR_FREE_CMA_PAGES);
1670#endif
1671
1672        if (free_pages - free_cma <= min + lowmem_reserve)
1673                return false;
1674        for (o = 0; o < order; o++) {
1675                /* At the next order, this order's pages become unavailable */
1676                free_pages -= z->free_area[o].nr_free << o;
1677
1678                /* Require fewer higher order pages to be free */
1679                min >>= 1;
1680
1681                if (free_pages <= min)
1682                        return false;
1683        }
1684        return true;
1685}
1686
1687bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1688                      int classzone_idx, int alloc_flags)
1689{
1690        return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1691                                        zone_page_state(z, NR_FREE_PAGES));
1692}
1693
1694bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark,
1695                      int classzone_idx, int alloc_flags)
1696{
1697        long free_pages = zone_page_state(z, NR_FREE_PAGES);
1698
1699        if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
1700                free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
1701
1702        return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1703                                                                free_pages);
1704}
1705
1706#ifdef CONFIG_NUMA
1707/*
1708 * zlc_setup - Setup for "zonelist cache".  Uses cached zone data to
1709 * skip over zones that are not allowed by the cpuset, or that have
1710 * been recently (in last second) found to be nearly full.  See further
1711 * comments in mmzone.h.  Reduces cache footprint of zonelist scans
1712 * that have to skip over a lot of full or unallowed zones.
1713 *
1714 * If the zonelist cache is present in the passed in zonelist, then
1715 * returns a pointer to the allowed node mask (either the current
1716 * tasks mems_allowed, or node_states[N_MEMORY].)
1717 *
1718 * If the zonelist cache is not available for this zonelist, does
1719 * nothing and returns NULL.
1720 *
1721 * If the fullzones BITMAP in the zonelist cache is stale (more than
1722 * a second since last zap'd) then we zap it out (clear its bits.)
1723 *
1724 * We hold off even calling zlc_setup, until after we've checked the
1725 * first zone in the zonelist, on the theory that most allocations will
1726 * be satisfied from that first zone, so best to examine that zone as
1727 * quickly as we can.
1728 */
1729static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1730{
1731        struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1732        nodemask_t *allowednodes;       /* zonelist_cache approximation */
1733
1734        zlc = zonelist->zlcache_ptr;
1735        if (!zlc)
1736                return NULL;
1737
1738        if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1739                bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1740                zlc->last_full_zap = jiffies;
1741        }
1742
1743        allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1744                                        &cpuset_current_mems_allowed :
1745                                        &node_states[N_MEMORY];
1746        return allowednodes;
1747}
1748
1749/*
1750 * Given 'z' scanning a zonelist, run a couple of quick checks to see
1751 * if it is worth looking at further for free memory:
1752 *  1) Check that the zone isn't thought to be full (doesn't have its
1753 *     bit set in the zonelist_cache fullzones BITMAP).
1754 *  2) Check that the zones node (obtained from the zonelist_cache
1755 *     z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1756 * Return true (non-zero) if zone is worth looking at further, or
1757 * else return false (zero) if it is not.
1758 *
1759 * This check -ignores- the distinction between various watermarks,
1760 * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ...  If a zone is
1761 * found to be full for any variation of these watermarks, it will
1762 * be considered full for up to one second by all requests, unless
1763 * we are so low on memory on all allowed nodes that we are forced
1764 * into the second scan of the zonelist.
1765 *
1766 * In the second scan we ignore this zonelist cache and exactly
1767 * apply the watermarks to all zones, even it is slower to do so.
1768 * We are low on memory in the second scan, and should leave no stone
1769 * unturned looking for a free page.
1770 */
1771static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1772                                                nodemask_t *allowednodes)
1773{
1774        struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1775        int i;                          /* index of *z in zonelist zones */
1776        int n;                          /* node that zone *z is on */
1777
1778        zlc = zonelist->zlcache_ptr;
1779        if (!zlc)
1780                return 1;
1781
1782        i = z - zonelist->_zonerefs;
1783        n = zlc->z_to_n[i];
1784
1785        /* This zone is worth trying if it is allowed but not full */
1786        return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1787}
1788
1789/*
1790 * Given 'z' scanning a zonelist, set the corresponding bit in
1791 * zlc->fullzones, so that subsequent attempts to allocate a page
1792 * from that zone don't waste time re-examining it.
1793 */
1794static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1795{
1796        struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1797        int i;                          /* index of *z in zonelist zones */
1798
1799        zlc = zonelist->zlcache_ptr;
1800        if (!zlc)
1801                return;
1802
1803        i = z - zonelist->_zonerefs;
1804
1805        set_bit(i, zlc->fullzones);
1806}
1807
1808/*
1809 * clear all zones full, called after direct reclaim makes progress so that
1810 * a zone that was recently full is not skipped over for up to a second
1811 */
1812static void zlc_clear_zones_full(struct zonelist *zonelist)
1813{
1814        struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1815
1816        zlc = zonelist->zlcache_ptr;
1817        if (!zlc)
1818                return;
1819
1820        bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1821}
1822
1823static bool zone_local(struct zone *local_zone, struct zone *zone)
1824{
1825        return node_distance(local_zone->node, zone->node) == LOCAL_DISTANCE;
1826}
1827
1828static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
1829{
1830        return node_isset(local_zone->node, zone->zone_pgdat->reclaim_nodes);
1831}
1832
1833static void __paginginit init_zone_allows_reclaim(int nid)
1834{
1835        int i;
1836
1837        for_each_online_node(i)
1838                if (node_distance(nid, i) <= RECLAIM_DISTANCE)
1839                        node_set(i, NODE_DATA(nid)->reclaim_nodes);
1840                else
1841                        zone_reclaim_mode = 1;
1842}
1843
1844#else   /* CONFIG_NUMA */
1845
1846static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1847{
1848        return NULL;
1849}
1850
1851static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1852                                nodemask_t *allowednodes)
1853{
1854        return 1;
1855}
1856
1857static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1858{
1859}
1860
1861static void zlc_clear_zones_full(struct zonelist *zonelist)
1862{
1863}
1864
1865static bool zone_local(struct zone *local_zone, struct zone *zone)
1866{
1867        return true;
1868}
1869
1870static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
1871{
1872        return true;
1873}
1874
1875static inline void init_zone_allows_reclaim(int nid)
1876{
1877}
1878#endif  /* CONFIG_NUMA */
1879
1880/*
1881 * get_page_from_freelist goes through the zonelist trying to allocate
1882 * a page.
1883 */
1884static struct page *
1885get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1886                struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
1887                struct zone *preferred_zone, int migratetype)
1888{
1889        struct zoneref *z;
1890        struct page *page = NULL;
1891        int classzone_idx;
1892        struct zone *zone;
1893        nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1894        int zlc_active = 0;             /* set if using zonelist_cache */
1895        int did_zlc_setup = 0;          /* just call zlc_setup() one time */
1896
1897        classzone_idx = zone_idx(preferred_zone);
1898zonelist_scan:
1899        /*
1900         * Scan zonelist, looking for a zone with enough free.
1901         * See also __cpuset_node_allowed_softwall() comment in kernel/cpuset.c.
1902         */
1903        for_each_zone_zonelist_nodemask(zone, z, zonelist,
1904                                                high_zoneidx, nodemask) {
1905                unsigned long mark;
1906
1907                if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
1908                        !zlc_zone_worth_trying(zonelist, z, allowednodes))
1909                                continue;
1910                if ((alloc_flags & ALLOC_CPUSET) &&
1911                        !cpuset_zone_allowed_softwall(zone, gfp_mask))
1912                                continue;
1913                BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
1914                if (unlikely(alloc_flags & ALLOC_NO_WATERMARKS))
1915                        goto try_this_zone;
1916                /*
1917                 * Distribute pages in proportion to the individual
1918                 * zone size to ensure fair page aging.  The zone a
1919                 * page was allocated in should have no effect on the
1920                 * time the page has in memory before being reclaimed.
1921                 *
1922                 * When zone_reclaim_mode is enabled, try to stay in
1923                 * local zones in the fastpath.  If that fails, the
1924                 * slowpath is entered, which will do another pass
1925                 * starting with the local zones, but ultimately fall
1926                 * back to remote zones that do not partake in the
1927                 * fairness round-robin cycle of this zonelist.
1928                 */
1929                if (alloc_flags & ALLOC_WMARK_LOW) {
1930                        if (zone_page_state(zone, NR_ALLOC_BATCH) <= 0)
1931                                continue;
1932                        if (zone_reclaim_mode &&
1933                            !zone_local(preferred_zone, zone))
1934                                continue;
1935                }
1936                /*
1937                 * When allocating a page cache page for writing, we
1938                 * want to get it from a zone that is within its dirty
1939                 * limit, such that no single zone holds more than its
1940                 * proportional share of globally allowed dirty pages.
1941                 * The dirty limits take into account the zone's
1942                 * lowmem reserves and high watermark so that kswapd
1943                 * should be able to balance it without having to
1944                 * write pages from its LRU list.
1945                 *
1946                 * This may look like it could increase pressure on
1947                 * lower zones by failing allocations in higher zones
1948                 * before they are full.  But the pages that do spill
1949                 * over are limited as the lower zones are protected
1950                 * by this very same mechanism.  It should not become
1951                 * a practical burden to them.
1952                 *
1953                 * XXX: For now, allow allocations to potentially
1954                 * exceed the per-zone dirty limit in the slowpath
1955                 * (ALLOC_WMARK_LOW unset) before going into reclaim,
1956                 * which is important when on a NUMA setup the allowed
1957                 * zones are together not big enough to reach the
1958                 * global limit.  The proper fix for these situations
1959                 * will require awareness of zones in the
1960                 * dirty-throttling and the flusher threads.
1961                 */
1962                if ((alloc_flags & ALLOC_WMARK_LOW) &&
1963                    (gfp_mask & __GFP_WRITE) && !zone_dirty_ok(zone))
1964                        goto this_zone_full;
1965
1966                mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
1967                if (!zone_watermark_ok(zone, order, mark,
1968                                       classzone_idx, alloc_flags)) {
1969                        int ret;
1970
1971                        if (IS_ENABLED(CONFIG_NUMA) &&
1972                                        !did_zlc_setup && nr_online_nodes > 1) {
1973                                /*
1974                                 * we do zlc_setup if there are multiple nodes
1975                                 * and before considering the first zone allowed
1976                                 * by the cpuset.
1977                                 */
1978                                allowednodes = zlc_setup(zonelist, alloc_flags);
1979                                zlc_active = 1;
1980                                did_zlc_setup = 1;
1981                        }
1982
1983                        if (zone_reclaim_mode == 0 ||
1984                            !zone_allows_reclaim(preferred_zone, zone))
1985                                goto this_zone_full;
1986
1987                        /*
1988                         * As we may have just activated ZLC, check if the first
1989                         * eligible zone has failed zone_reclaim recently.
1990                         */
1991                        if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
1992                                !zlc_zone_worth_trying(zonelist, z, allowednodes))
1993                                continue;
1994
1995                        ret = zone_reclaim(zone, gfp_mask, order);
1996                        switch (ret) {
1997                        case ZONE_RECLAIM_NOSCAN:
1998                                /* did not scan */
1999                                continue;
2000                        case ZONE_RECLAIM_FULL:
2001                                /* scanned but unreclaimable */
2002                                continue;
2003                        default:
2004                                /* did we reclaim enough */
2005                                if (zone_watermark_ok(zone, order, mark,
2006                                                classzone_idx, alloc_flags))
2007                                        goto try_this_zone;
2008
2009                                /*
2010                                 * Failed to reclaim enough to meet watermark.
2011                                 * Only mark the zone full if checking the min
2012                                 * watermark or if we failed to reclaim just
2013                                 * 1<<order pages or else the page allocator
2014                                 * fastpath will prematurely mark zones full
2015                                 * when the watermark is between the low and
2016                                 * min watermarks.
2017                                 */
2018                                if (((alloc_flags & ALLOC_WMARK_MASK) == ALLOC_WMARK_MIN) ||
2019                                    ret == ZONE_RECLAIM_SOME)
2020                                        goto this_zone_full;
2021
2022                                continue;
2023                        }
2024                }
2025
2026try_this_zone:
2027                page = buffered_rmqueue(preferred_zone, zone, order,
2028                                                gfp_mask, migratetype);
2029                if (page)
2030                        break;
2031this_zone_full:
2032                if (IS_ENABLED(CONFIG_NUMA))
2033                        zlc_mark_zone_full(zonelist, z);
2034        }
2035
2036        if (unlikely(IS_ENABLED(CONFIG_NUMA) && page == NULL && zlc_active)) {
2037                /* Disable zlc cache for second zonelist scan */
2038                zlc_active = 0;
2039                goto zonelist_scan;
2040        }
2041
2042        if (page)
2043                /*
2044                 * page->pfmemalloc is set when ALLOC_NO_WATERMARKS was
2045                 * necessary to allocate the page. The expectation is
2046                 * that the caller is taking steps that will free more
2047                 * memory. The caller should avoid the page being used
2048                 * for !PFMEMALLOC purposes.
2049                 */
2050                page->pfmemalloc = !!(alloc_flags & ALLOC_NO_WATERMARKS);
2051
2052        return page;
2053}
2054
2055/*
2056 * Large machines with many possible nodes should not always dump per-node
2057 * meminfo in irq context.
2058 */
2059static inline bool should_suppress_show_mem(void)
2060{
2061        bool ret = false;
2062
2063#if NODES_SHIFT > 8
2064        ret = in_interrupt();
2065#endif
2066        return ret;
2067}
2068
2069static DEFINE_RATELIMIT_STATE(nopage_rs,
2070                DEFAULT_RATELIMIT_INTERVAL,
2071                DEFAULT_RATELIMIT_BURST);
2072
2073void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...)
2074{
2075        unsigned int filter = SHOW_MEM_FILTER_NODES;
2076
2077        if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) ||
2078            debug_guardpage_minorder() > 0)
2079                return;
2080
2081        /*
2082         * Walking all memory to count page types is very expensive and should
2083         * be inhibited in non-blockable contexts.
2084         */
2085        if (!(gfp_mask & __GFP_WAIT))
2086                filter |= SHOW_MEM_FILTER_PAGE_COUNT;
2087
2088        /*
2089         * This documents exceptions given to allocations in certain
2090         * contexts that are allowed to allocate outside current's set
2091         * of allowed nodes.
2092         */
2093        if (!(gfp_mask & __GFP_NOMEMALLOC))
2094                if (test_thread_flag(TIF_MEMDIE) ||
2095                    (current->flags & (PF_MEMALLOC | PF_EXITING)))
2096                        filter &= ~SHOW_MEM_FILTER_NODES;
2097        if (in_interrupt() || !(gfp_mask & __GFP_WAIT))
2098                filter &= ~SHOW_MEM_FILTER_NODES;
2099
2100        if (fmt) {
2101                struct va_format vaf;
2102                va_list args;
2103
2104                va_start(args, fmt);
2105
2106                vaf.fmt = fmt;
2107                vaf.va = &args;
2108
2109                pr_warn("%pV", &vaf);
2110
2111                va_end(args);
2112        }
2113
2114        pr_warn("%s: page allocation failure: order:%d, mode:0x%x\n",
2115                current->comm, order, gfp_mask);
2116
2117        dump_stack();
2118        if (!should_suppress_show_mem())
2119                show_mem(filter);
2120}
2121
2122static inline int
2123should_alloc_retry(gfp_t gfp_mask, unsigned int order,
2124                                unsigned long did_some_progress,
2125                                unsigned long pages_reclaimed)
2126{
2127        /* Do not loop if specifically requested */
2128        if (gfp_mask & __GFP_NORETRY)
2129                return 0;
2130
2131        /* Always retry if specifically requested */
2132        if (gfp_mask & __GFP_NOFAIL)
2133                return 1;
2134
2135        /*
2136         * Suspend converts GFP_KERNEL to __GFP_WAIT which can prevent reclaim
2137         * making forward progress without invoking OOM. Suspend also disables
2138         * storage devices so kswapd will not help. Bail if we are suspending.
2139         */
2140        if (!did_some_progress && pm_suspended_storage())
2141                return 0;
2142
2143        /*
2144         * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
2145         * means __GFP_NOFAIL, but that may not be true in other
2146         * implementations.
2147         */
2148        if (order <= PAGE_ALLOC_COSTLY_ORDER)
2149                return 1;
2150
2151        /*
2152         * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
2153         * specified, then we retry until we no longer reclaim any pages
2154         * (above), or we've reclaimed an order of pages at least as
2155         * large as the allocation's order. In both cases, if the
2156         * allocation still fails, we stop retrying.
2157         */
2158        if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
2159                return 1;
2160
2161        return 0;
2162}
2163
2164static inline struct page *
2165__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
2166        struct zonelist *zonelist, enum zone_type high_zoneidx,
2167        nodemask_t *nodemask, struct zone *preferred_zone,
2168        int migratetype)
2169{
2170        struct page *page;
2171
2172        /* Acquire the OOM killer lock for the zones in zonelist */
2173        if (!try_set_zonelist_oom(zonelist, gfp_mask)) {
2174                schedule_timeout_uninterruptible(1);
2175                return NULL;
2176        }
2177
2178        /*
2179         * Go through the zonelist yet one more time, keep very high watermark
2180         * here, this is only to catch a parallel oom killing, we must fail if
2181         * we're still under heavy pressure.
2182         */
2183        page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
2184                order, zonelist, high_zoneidx,
2185                ALLOC_WMARK_HIGH|ALLOC_CPUSET,
2186                preferred_zone, migratetype);
2187        if (page)
2188                goto out;
2189
2190        if (!(gfp_mask & __GFP_NOFAIL)) {
2191                /* The OOM killer will not help higher order allocs */
2192                if (order > PAGE_ALLOC_COSTLY_ORDER)
2193                        goto out;
2194                /* The OOM killer does not needlessly kill tasks for lowmem */
2195                if (high_zoneidx < ZONE_NORMAL)
2196                        goto out;
2197                /*
2198                 * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
2199                 * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
2200                 * The caller should handle page allocation failure by itself if
2201                 * it specifies __GFP_THISNODE.
2202                 * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
2203                 */
2204                if (gfp_mask & __GFP_THISNODE)
2205                        goto out;
2206        }
2207        /* Exhausted what can be done so it's blamo time */
2208        out_of_memory(zonelist, gfp_mask, order, nodemask, false);
2209
2210out:
2211        clear_zonelist_oom(zonelist, gfp_mask);
2212        return page;
2213}
2214
2215#ifdef CONFIG_COMPACTION
2216/* Try memory compaction for high-order allocations before reclaim */
2217static struct page *
2218__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2219        struct zonelist *zonelist, enum zone_type high_zoneidx,
2220        nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2221        int migratetype, bool sync_migration,
2222        bool *contended_compaction, bool *deferred_compaction,
2223        unsigned long *did_some_progress)
2224{
2225        if (!order)
2226                return NULL;
2227
2228        if (compaction_deferred(preferred_zone, order)) {
2229                *deferred_compaction = true;
2230                return NULL;
2231        }
2232
2233        current->flags |= PF_MEMALLOC;
2234        *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
2235                                                nodemask, sync_migration,
2236                                                contended_compaction);
2237        current->flags &= ~PF_MEMALLOC;
2238
2239        if (*did_some_progress != COMPACT_SKIPPED) {
2240                struct page *page;
2241
2242                /* Page migration frees to the PCP lists but we want merging */
2243                drain_pages(get_cpu());
2244                put_cpu();
2245
2246                page = get_page_from_freelist(gfp_mask, nodemask,
2247                                order, zonelist, high_zoneidx,
2248                                alloc_flags & ~ALLOC_NO_WATERMARKS,
2249                                preferred_zone, migratetype);
2250                if (page) {
2251                        preferred_zone->compact_blockskip_flush = false;
2252                        preferred_zone->compact_considered = 0;
2253                        preferred_zone->compact_defer_shift = 0;
2254                        if (order >= preferred_zone->compact_order_failed)
2255                                preferred_zone->compact_order_failed = order + 1;
2256                        count_vm_event(COMPACTSUCCESS);
2257                        return page;
2258                }
2259
2260                /*
2261                 * It's bad if compaction run occurs and fails.
2262                 * The most likely reason is that pages exist,
2263                 * but not enough to satisfy watermarks.
2264                 */
2265                count_vm_event(COMPACTFAIL);
2266
2267                /*
2268                 * As async compaction considers a subset of pageblocks, only
2269                 * defer if the failure was a sync compaction failure.
2270                 */
2271                if (sync_migration)
2272                        defer_compaction(preferred_zone, order);
2273
2274                cond_resched();
2275        }
2276
2277        return NULL;
2278}
2279#else
2280static inline struct page *
2281__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2282        struct zonelist *zonelist, enum zone_type high_zoneidx,
2283        nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2284        int migratetype, bool sync_migration,
2285        bool *contended_compaction, bool *deferred_compaction,
2286        unsigned long *did_some_progress)
2287{
2288        return NULL;
2289}
2290#endif /* CONFIG_COMPACTION */
2291
2292/* Perform direct synchronous page reclaim */
2293static int
2294__perform_reclaim(gfp_t gfp_mask, unsigned int order, struct zonelist *zonelist,
2295                  nodemask_t *nodemask)
2296{
2297        struct reclaim_state reclaim_state;
2298        int progress;
2299
2300        cond_resched();
2301
2302        /* We now go into synchronous reclaim */
2303        cpuset_memory_pressure_bump();
2304        current->flags |= PF_MEMALLOC;
2305        lockdep_set_current_reclaim_state(gfp_mask);
2306        reclaim_state.reclaimed_slab = 0;
2307        current->reclaim_state = &reclaim_state;
2308
2309        progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
2310
2311        current->reclaim_state = NULL;
2312        lockdep_clear_current_reclaim_state();
2313        current->flags &= ~PF_MEMALLOC;
2314
2315        cond_resched();
2316
2317        return progress;
2318}
2319
2320/* The really slow allocator path where we enter direct reclaim */
2321static inline struct page *
2322__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
2323        struct zonelist *zonelist, enum zone_type high_zoneidx,
2324        nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2325        int migratetype, unsigned long *did_some_progress)
2326{
2327        struct page *page = NULL;
2328        bool drained = false;
2329
2330        *did_some_progress = __perform_reclaim(gfp_mask, order, zonelist,
2331                                               nodemask);
2332        if (unlikely(!(*did_some_progress)))
2333                return NULL;
2334
2335        /* After successful reclaim, reconsider all zones for allocation */
2336        if (IS_ENABLED(CONFIG_NUMA))
2337                zlc_clear_zones_full(zonelist);
2338
2339retry:
2340        page = get_page_from_freelist(gfp_mask, nodemask, order,
2341                                        zonelist, high_zoneidx,
2342                                        alloc_flags & ~ALLOC_NO_WATERMARKS,
2343                                        preferred_zone, migratetype);
2344
2345        /*
2346         * If an allocation failed after direct reclaim, it could be because
2347         * pages are pinned on the per-cpu lists. Drain them and try again
2348         */
2349        if (!page && !drained) {
2350                drain_all_pages();
2351                drained = true;
2352                goto retry;
2353        }
2354
2355        return page;
2356}
2357
2358/*
2359 * This is called in the allocator slow-path if the allocation request is of
2360 * sufficient urgency to ignore watermarks and take other desperate measures
2361 */
2362static inline struct page *
2363__alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
2364        struct zonelist *zonelist, enum zone_type high_zoneidx,
2365        nodemask_t *nodemask, struct zone *preferred_zone,
2366        int migratetype)
2367{
2368        struct page *page;
2369
2370        do {
2371                page = get_page_from_freelist(gfp_mask, nodemask, order,
2372                        zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
2373                        preferred_zone, migratetype);
2374
2375                if (!page && gfp_mask & __GFP_NOFAIL)
2376                        wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2377        } while (!page && (gfp_mask & __GFP_NOFAIL));
2378
2379        return page;
2380}
2381
2382static void prepare_slowpath(gfp_t gfp_mask, unsigned int order,
2383                             struct zonelist *zonelist,
2384                             enum zone_type high_zoneidx,
2385                             struct zone *preferred_zone)
2386{
2387        struct zoneref *z;
2388        struct zone *zone;
2389
2390        for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
2391                if (!(gfp_mask & __GFP_NO_KSWAPD))
2392                        wakeup_kswapd(zone, order, zone_idx(preferred_zone));
2393                /*
2394                 * Only reset the batches of zones that were actually
2395                 * considered in the fast path, we don't want to
2396                 * thrash fairness information for zones that are not
2397                 * actually part of this zonelist's round-robin cycle.
2398                 */
2399                if (zone_reclaim_mode && !zone_local(preferred_zone, zone))
2400                        continue;
2401                mod_zone_page_state(zone, NR_ALLOC_BATCH,
2402                                    high_wmark_pages(zone) -
2403                                    low_wmark_pages(zone) -
2404                                    zone_page_state(zone, NR_ALLOC_BATCH));
2405        }
2406}
2407
2408static inline int
2409gfp_to_alloc_flags(gfp_t gfp_mask)
2410{
2411        int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
2412        const gfp_t wait = gfp_mask & __GFP_WAIT;
2413
2414        /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
2415        BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
2416
2417        /*
2418         * The caller may dip into page reserves a bit more if the caller
2419         * cannot run direct reclaim, or if the caller has realtime scheduling
2420         * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
2421         * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
2422         */
2423        alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
2424
2425        if (!wait) {
2426                /*
2427                 * Not worth trying to allocate harder for
2428                 * __GFP_NOMEMALLOC even if it can't schedule.
2429                 */
2430                if  (!(gfp_mask & __GFP_NOMEMALLOC))
2431                        alloc_flags |= ALLOC_HARDER;
2432                /*
2433                 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
2434                 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
2435                 */
2436                alloc_flags &= ~ALLOC_CPUSET;
2437        } else if (unlikely(rt_task(current)) && !in_interrupt())
2438                alloc_flags |= ALLOC_HARDER;
2439
2440        if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
2441                if (gfp_mask & __GFP_MEMALLOC)
2442                        alloc_flags |= ALLOC_NO_WATERMARKS;
2443                else if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
2444                        alloc_flags |= ALLOC_NO_WATERMARKS;
2445                else if (!in_interrupt() &&
2446                                ((current->flags & PF_MEMALLOC) ||
2447                                 unlikely(test_thread_flag(TIF_MEMDIE))))
2448                        alloc_flags |= ALLOC_NO_WATERMARKS;
2449        }
2450#ifdef CONFIG_CMA
2451        if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
2452                alloc_flags |= ALLOC_CMA;
2453#endif
2454        return alloc_flags;
2455}
2456
2457bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
2458{
2459        return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_NO_WATERMARKS);
2460}
2461
2462static inline struct page *
2463__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
2464        struct zonelist *zonelist, enum zone_type high_zoneidx,
2465        nodemask_t *nodemask, struct zone *preferred_zone,
2466        int migratetype)
2467{
2468        const gfp_t wait = gfp_mask & __GFP_WAIT;
2469        struct page *page = NULL;
2470        int alloc_flags;
2471        unsigned long pages_reclaimed = 0;
2472        unsigned long did_some_progress;
2473        bool sync_migration = false;
2474        bool deferred_compaction = false;
2475        bool contended_compaction = false;
2476
2477        /*
2478         * In the slowpath, we sanity check order to avoid ever trying to
2479         * reclaim >= MAX_ORDER areas which will never succeed. Callers may
2480         * be using allocators in order of preference for an area that is
2481         * too large.
2482         */
2483        if (order >= MAX_ORDER) {
2484                WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
2485                return NULL;
2486        }
2487
2488        /*
2489         * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
2490         * __GFP_NOWARN set) should not cause reclaim since the subsystem
2491         * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
2492         * using a larger set of nodes after it has established that the
2493         * allowed per node queues are empty and that nodes are
2494         * over allocated.
2495         */
2496        if (IS_ENABLED(CONFIG_NUMA) &&
2497                        (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
2498                goto nopage;
2499
2500restart:
2501        prepare_slowpath(gfp_mask, order, zonelist,
2502                         high_zoneidx, preferred_zone);
2503
2504        /*
2505         * OK, we're below the kswapd watermark and have kicked background
2506         * reclaim. Now things get more complex, so set up alloc_flags according
2507         * to how we want to proceed.
2508         */
2509        alloc_flags = gfp_to_alloc_flags(gfp_mask);
2510
2511        /*
2512         * Find the true preferred zone if the allocation is unconstrained by
2513         * cpusets.
2514         */
2515        if (!(alloc_flags & ALLOC_CPUSET) && !nodemask)
2516                first_zones_zonelist(zonelist, high_zoneidx, NULL,
2517                                        &preferred_zone);
2518
2519rebalance:
2520        /* This is the last chance, in general, before the goto nopage. */
2521        page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
2522                        high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
2523                        preferred_zone, migratetype);
2524        if (page)
2525                goto got_pg;
2526
2527        /* Allocate without watermarks if the context allows */
2528        if (alloc_flags & ALLOC_NO_WATERMARKS) {
2529                /*
2530                 * Ignore mempolicies if ALLOC_NO_WATERMARKS on the grounds
2531                 * the allocation is high priority and these type of
2532                 * allocations are system rather than user orientated
2533                 */
2534                zonelist = node_zonelist(numa_node_id(), gfp_mask);
2535
2536                page = __alloc_pages_high_priority(gfp_mask, order,
2537                                zonelist, high_zoneidx, nodemask,
2538                                preferred_zone, migratetype);
2539                if (page) {
2540                        goto got_pg;
2541                }
2542        }
2543
2544        /* Atomic allocations - we can't balance anything */
2545        if (!wait)
2546                goto nopage;
2547
2548        /* Avoid recursion of direct reclaim */
2549        if (current->flags & PF_MEMALLOC)
2550                goto nopage;
2551
2552        /* Avoid allocations with no watermarks from looping endlessly */
2553        if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
2554                goto nopage;
2555
2556        /*
2557         * Try direct compaction. The first pass is asynchronous. Subsequent
2558         * attempts after direct reclaim are synchronous
2559         */
2560        page = __alloc_pages_direct_compact(gfp_mask, order,
2561                                        zonelist, high_zoneidx,
2562                                        nodemask,
2563                                        alloc_flags, preferred_zone,
2564                                        migratetype, sync_migration,
2565                                        &contended_compaction,
2566                                        &deferred_compaction,
2567                                        &did_some_progress);
2568        if (page)
2569                goto got_pg;
2570        sync_migration = true;
2571
2572        /*
2573         * If compaction is deferred for high-order allocations, it is because
2574         * sync compaction recently failed. In this is the case and the caller
2575         * requested a movable allocation that does not heavily disrupt the
2576         * system then fail the allocation instead of entering direct reclaim.
2577         */
2578        if ((deferred_compaction || contended_compaction) &&
2579                                                (gfp_mask & __GFP_NO_KSWAPD))
2580                goto nopage;
2581
2582        /* Try direct reclaim and then allocating */
2583        page = __alloc_pages_direct_reclaim(gfp_mask, order,
2584                                        zonelist, high_zoneidx,
2585                                        nodemask,
2586                                        alloc_flags, preferred_zone,
2587                                        migratetype, &did_some_progress);
2588        if (page)
2589                goto got_pg;
2590
2591        /*
2592         * If we failed to make any progress reclaiming, then we are
2593         * running out of options and have to consider going OOM
2594         */
2595        if (!did_some_progress) {
2596                if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
2597                        if (oom_killer_disabled)
2598                                goto nopage;
2599                        /* Coredumps can quickly deplete all memory reserves */
2600                        if ((current->flags & PF_DUMPCORE) &&
2601                            !(gfp_mask & __GFP_NOFAIL))
2602                                goto nopage;
2603                        page = __alloc_pages_may_oom(gfp_mask, order,
2604                                        zonelist, high_zoneidx,
2605                                        nodemask, preferred_zone,
2606                                        migratetype);
2607                        if (page)
2608                                goto got_pg;
2609
2610                        if (!(gfp_mask & __GFP_NOFAIL)) {
2611                                /*
2612                                 * The oom killer is not called for high-order
2613                                 * allocations that may fail, so if no progress
2614                                 * is being made, there are no other options and
2615                                 * retrying is unlikely to help.
2616                                 */
2617                                if (order > PAGE_ALLOC_COSTLY_ORDER)
2618                                        goto nopage;
2619                                /*
2620                                 * The oom killer is not called for lowmem
2621                                 * allocations to prevent needlessly killing
2622                                 * innocent tasks.
2623                                 */
2624                                if (high_zoneidx < ZONE_NORMAL)
2625                                        goto nopage;
2626                        }
2627
2628                        goto restart;
2629                }
2630        }
2631
2632        /* Check if we should retry the allocation */
2633        pages_reclaimed += did_some_progress;
2634        if (should_alloc_retry(gfp_mask, order, did_some_progress,
2635                                                pages_reclaimed)) {
2636                /* Wait for some write requests to complete then retry */
2637                wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2638                goto rebalance;
2639        } else {
2640                /*
2641                 * High-order allocations do not necessarily loop after
2642                 * direct reclaim and reclaim/compaction depends on compaction
2643                 * being called after reclaim so call directly if necessary
2644                 */
2645                page = __alloc_pages_direct_compact(gfp_mask, order,
2646                                        zonelist, high_zoneidx,
2647                                        nodemask,
2648                                        alloc_flags, preferred_zone,
2649                                        migratetype, sync_migration,
2650                                        &contended_compaction,
2651                                        &deferred_compaction,
2652                                        &did_some_progress);
2653                if (page)
2654                        goto got_pg;
2655        }
2656
2657nopage:
2658        warn_alloc_failed(gfp_mask, order, NULL);
2659        return page;
2660got_pg:
2661        if (kmemcheck_enabled)
2662                kmemcheck_pagealloc_alloc(page, order, gfp_mask);
2663
2664        return page;
2665}
2666
2667/*
2668 * This is the 'heart' of the zoned buddy allocator.
2669 */
2670struct page *
2671__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
2672                        struct zonelist *zonelist, nodemask_t *nodemask)
2673{
2674        enum zone_type high_zoneidx = gfp_zone(gfp_mask);
2675        struct zone *preferred_zone;
2676        struct page *page = NULL;
2677        int migratetype = allocflags_to_migratetype(gfp_mask);
2678        unsigned int cpuset_mems_cookie;
2679        int alloc_flags = ALLOC_WMARK_LOW|ALLOC_CPUSET;
2680        struct mem_cgroup *memcg = NULL;
2681
2682        gfp_mask &= gfp_allowed_mask;
2683
2684        lockdep_trace_alloc(gfp_mask);
2685
2686        might_sleep_if(gfp_mask & __GFP_WAIT);
2687
2688        if (should_fail_alloc_page(gfp_mask, order))
2689                return NULL;
2690
2691        /*
2692         * Check the zones suitable for the gfp_mask contain at least one
2693         * valid zone. It's possible to have an empty zonelist as a result
2694         * of GFP_THISNODE and a memoryless node
2695         */
2696        if (unlikely(!zonelist->_zonerefs->zone))
2697                return NULL;
2698
2699        /*
2700         * Will only have any effect when __GFP_KMEMCG is set.  This is
2701         * verified in the (always inline) callee
2702         */
2703        if (!memcg_kmem_newpage_charge(gfp_mask, &memcg, order))
2704                return NULL;
2705
2706retry_cpuset:
2707        cpuset_mems_cookie = get_mems_allowed();
2708
2709        /* The preferred zone is used for statistics later */
2710        first_zones_zonelist(zonelist, high_zoneidx,
2711                                nodemask ? : &cpuset_current_mems_allowed,
2712                                &preferred_zone);
2713        if (!preferred_zone)
2714                goto out;
2715
2716#ifdef CONFIG_CMA
2717        if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
2718                alloc_flags |= ALLOC_CMA;
2719#endif
2720        /* First allocation attempt */
2721        page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
2722                        zonelist, high_zoneidx, alloc_flags,
2723                        preferred_zone, migratetype);
2724        if (unlikely(!page)) {
2725                /*
2726                 * Runtime PM, block IO and its error handling path
2727                 * can deadlock because I/O on the device might not
2728                 * complete.
2729                 */
2730                gfp_mask = memalloc_noio_flags(gfp_mask);
2731                page = __alloc_pages_slowpath(gfp_mask, order,
2732                                zonelist, high_zoneidx, nodemask,
2733                                preferred_zone, migratetype);
2734        }
2735
2736        trace_mm_page_alloc(page, order, gfp_mask, migratetype);
2737
2738out:
2739        /*
2740         * When updating a task's mems_allowed, it is possible to race with
2741         * parallel threads in such a way that an allocation can fail while
2742         * the mask is being updated. If a page allocation is about to fail,
2743         * check if the cpuset changed during allocation and if so, retry.
2744         */
2745        if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
2746                goto retry_cpuset;
2747
2748        memcg_kmem_commit_charge(page, memcg, order);
2749
2750        return page;
2751}
2752EXPORT_SYMBOL(__alloc_pages_nodemask);
2753
2754/*
2755 * Common helper functions.
2756 */
2757unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
2758{
2759        struct page *page;
2760
2761        /*
2762         * __get_free_pages() returns a 32-bit address, which cannot represent
2763         * a highmem page
2764         */
2765        VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
2766
2767        page = alloc_pages(gfp_mask, order);
2768        if (!page)
2769                return 0;
2770        return (unsigned long) page_address(page);
2771}
2772EXPORT_SYMBOL(__get_free_pages);
2773
2774unsigned long get_zeroed_page(gfp_t gfp_mask)
2775{
2776        return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
2777}
2778EXPORT_SYMBOL(get_zeroed_page);
2779
2780void __free_pages(struct page *page, unsigned int order)
2781{
2782        if (put_page_testzero(page)) {
2783                if (order == 0)
2784                        free_hot_cold_page(page, 0);
2785                else
2786                        __free_pages_ok(page, order);
2787        }
2788}
2789
2790EXPORT_SYMBOL(__free_pages);
2791
2792void free_pages(unsigned long addr, unsigned int order)
2793{
2794        if (addr != 0) {
2795                VM_BUG_ON(!virt_addr_valid((void *)addr));
2796                __free_pages(virt_to_page((void *)addr), order);
2797        }
2798}
2799
2800EXPORT_SYMBOL(free_pages);
2801
2802/*
2803 * __free_memcg_kmem_pages and free_memcg_kmem_pages will free
2804 * pages allocated with __GFP_KMEMCG.
2805 *
2806 * Those pages are accounted to a particular memcg, embedded in the
2807 * corresponding page_cgroup. To avoid adding a hit in the allocator to search
2808 * for that information only to find out that it is NULL for users who have no
2809 * interest in that whatsoever, we provide these functions.
2810 *
2811 * The caller knows better which flags it relies on.
2812 */
2813void __free_memcg_kmem_pages(struct page *page, unsigned int order)
2814{
2815        memcg_kmem_uncharge_pages(page, order);
2816        __free_pages(page, order);
2817}
2818
2819void free_memcg_kmem_pages(unsigned long addr, unsigned int order)
2820{
2821        if (addr != 0) {
2822                VM_BUG_ON(!virt_addr_valid((void *)addr));
2823                __free_memcg_kmem_pages(virt_to_page((void *)addr), order);
2824        }
2825}
2826
2827static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
2828{
2829        if (addr) {
2830                unsigned long alloc_end = addr + (PAGE_SIZE << order);
2831                unsigned long used = addr + PAGE_ALIGN(size);
2832
2833                split_page(virt_to_page((void *)addr), order);
2834                while (used < alloc_end) {
2835                        free_page(used);
2836                        used += PAGE_SIZE;
2837                }
2838        }
2839        return (void *)addr;
2840}
2841
2842/**
2843 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
2844 * @size: the number of bytes to allocate
2845 * @gfp_mask: GFP flags for the allocation
2846 *
2847 * This function is similar to alloc_pages(), except that it allocates the
2848 * minimum number of pages to satisfy the request.  alloc_pages() can only
2849 * allocate memory in power-of-two pages.
2850 *
2851 * This function is also limited by MAX_ORDER.
2852 *
2853 * Memory allocated by this function must be released by free_pages_exact().
2854 */
2855void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
2856{
2857        unsigned int order = get_order(size);
2858        unsigned long addr;
2859
2860        addr = __get_free_pages(gfp_mask, order);
2861        return make_alloc_exact(addr, order, size);
2862}
2863EXPORT_SYMBOL(alloc_pages_exact);
2864
2865/**
2866 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
2867 *                         pages on a node.
2868 * @nid: the preferred node ID where memory should be allocated
2869 * @size: the number of bytes to allocate
2870 * @gfp_mask: GFP flags for the allocation
2871 *
2872 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
2873 * back.
2874 * Note this is not alloc_pages_exact_node() which allocates on a specific node,
2875 * but is not exact.
2876 */
2877void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
2878{
2879        unsigned order = get_order(size);
2880        struct page *p = alloc_pages_node(nid, gfp_mask, order);
2881        if (!p)
2882                return NULL;
2883        return make_alloc_exact((unsigned long)page_address(p), order, size);
2884}
2885EXPORT_SYMBOL(alloc_pages_exact_nid);
2886
2887/**
2888 * free_pages_exact - release memory allocated via alloc_pages_exact()
2889 * @virt: the value returned by alloc_pages_exact.
2890 * @size: size of allocation, same value as passed to alloc_pages_exact().
2891 *
2892 * Release the memory allocated by a previous call to alloc_pages_exact.
2893 */
2894void free_pages_exact(void *virt, size_t size)
2895{
2896        unsigned long addr = (unsigned long)virt;
2897        unsigned long end = addr + PAGE_ALIGN(size);
2898
2899        while (addr < end) {
2900                free_page(addr);
2901                addr += PAGE_SIZE;
2902        }
2903}
2904EXPORT_SYMBOL(free_pages_exact);
2905
2906/**
2907 * nr_free_zone_pages - count number of pages beyond high watermark
2908 * @offset: The zone index of the highest zone
2909 *
2910 * nr_free_zone_pages() counts the number of counts pages which are beyond the
2911 * high watermark within all zones at or below a given zone index.  For each
2912 * zone, the number of pages is calculated as:
2913 *     managed_pages - high_pages
2914 */
2915static unsigned long nr_free_zone_pages(int offset)
2916{
2917        struct zoneref *z;
2918        struct zone *zone;
2919
2920        /* Just pick one node, since fallback list is circular */
2921        unsigned long sum = 0;
2922
2923        struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
2924
2925        for_each_zone_zonelist(zone, z, zonelist, offset) {
2926                unsigned long size = zone->managed_pages;
2927                unsigned long high = high_wmark_pages(zone);
2928                if (size > high)
2929                        sum += size - high;
2930        }
2931
2932        return sum;
2933}
2934
2935/**
2936 * nr_free_buffer_pages - count number of pages beyond high watermark
2937 *
2938 * nr_free_buffer_pages() counts the number of pages which are beyond the high
2939 * watermark within ZONE_DMA and ZONE_NORMAL.
2940 */
2941unsigned long nr_free_buffer_pages(void)
2942{
2943        return nr_free_zone_pages(gfp_zone(GFP_USER));
2944}
2945EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
2946
2947/**
2948 * nr_free_pagecache_pages - count number of pages beyond high watermark
2949 *
2950 * nr_free_pagecache_pages() counts the number of pages which are beyond the
2951 * high watermark within all zones.
2952 */
2953unsigned long nr_free_pagecache_pages(void)
2954{
2955        return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
2956}
2957
2958static inline void show_node(struct zone *zone)
2959{
2960        if (IS_ENABLED(CONFIG_NUMA))
2961                printk("Node %d ", zone_to_nid(zone));
2962}
2963
2964void si_meminfo(struct sysinfo *val)
2965{
2966        val->totalram = totalram_pages;
2967        val->sharedram = 0;
2968        val->freeram = global_page_state(NR_FREE_PAGES);
2969        val->bufferram = nr_blockdev_pages();
2970        val->totalhigh = totalhigh_pages;
2971        val->freehigh = nr_free_highpages();
2972        val->mem_unit = PAGE_SIZE;
2973}
2974
2975EXPORT_SYMBOL(si_meminfo);
2976
2977#ifdef CONFIG_NUMA
2978void si_meminfo_node(struct sysinfo *val, int nid)
2979{
2980        int zone_type;          /* needs to be signed */
2981        unsigned long managed_pages = 0;
2982        pg_data_t *pgdat = NODE_DATA(nid);
2983
2984        for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
2985                managed_pages += pgdat->node_zones[zone_type].managed_pages;
2986        val->totalram = managed_pages;
2987        val->freeram = node_page_state(nid, NR_FREE_PAGES);
2988#ifdef CONFIG_HIGHMEM
2989        val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].managed_pages;
2990        val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
2991                        NR_FREE_PAGES);
2992#else
2993        val->totalhigh = 0;
2994        val->freehigh = 0;
2995#endif
2996        val->mem_unit = PAGE_SIZE;
2997}
2998#endif
2999
3000/*
3001 * Determine whether the node should be displayed or not, depending on whether
3002 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
3003 */
3004bool skip_free_areas_node(unsigned int flags, int nid)
3005{
3006        bool ret = false;
3007        unsigned int cpuset_mems_cookie;
3008
3009        if (!(flags & SHOW_MEM_FILTER_NODES))
3010                goto out;
3011
3012        do {
3013                cpuset_mems_cookie = get_mems_allowed();
3014                ret = !node_isset(nid, cpuset_current_mems_allowed);
3015        } while (!put_mems_allowed(cpuset_mems_cookie));
3016out:
3017        return ret;
3018}
3019
3020#define K(x) ((x) << (PAGE_SHIFT-10))
3021
3022static void show_migration_types(unsigned char type)
3023{
3024        static const char types[MIGRATE_TYPES] = {
3025                [MIGRATE_UNMOVABLE]     = 'U',
3026                [MIGRATE_RECLAIMABLE]   = 'E',
3027                [MIGRATE_MOVABLE]       = 'M',
3028                [MIGRATE_RESERVE]       = 'R',
3029#ifdef CONFIG_CMA
3030                [MIGRATE_CMA]           = 'C',
3031#endif
3032#ifdef CONFIG_MEMORY_ISOLATION
3033                [MIGRATE_ISOLATE]       = 'I',
3034#endif
3035        };
3036        char tmp[MIGRATE_TYPES + 1];
3037        char *p = tmp;
3038        int i;
3039
3040        for (i = 0; i < MIGRATE_TYPES; i++) {
3041                if (type & (1 << i))
3042                        *p++ = types[i];
3043        }
3044
3045        *p = '\0';
3046        printk("(%s) ", tmp);
3047}
3048
3049/*
3050 * Show free area list (used inside shift_scroll-lock stuff)
3051 * We also calculate the percentage fragmentation. We do this by counting the
3052 * memory on each free list with the exception of the first item on the list.
3053 * Suppresses nodes that are not allowed by current's cpuset if
3054 * SHOW_MEM_FILTER_NODES is passed.
3055 */
3056void show_free_areas(unsigned int filter)
3057{
3058        int cpu;
3059        struct zone *zone;
3060
3061        for_each_populated_zone(zone) {
3062                if (skip_free_areas_node(filter, zone_to_nid(zone)))
3063                        continue;
3064                show_node(zone);
3065                printk("%s per-cpu:\n", zone->name);
3066
3067                for_each_online_cpu(cpu) {
3068                        struct per_cpu_pageset *pageset;
3069
3070                        pageset = per_cpu_ptr(zone->pageset, cpu);
3071
3072                        printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
3073                               cpu, pageset->pcp.high,
3074                               pageset->pcp.batch, pageset->pcp.count);
3075                }
3076        }
3077
3078        printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
3079                " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
3080                " unevictable:%lu"
3081                " dirty:%lu writeback:%lu unstable:%lu\n"
3082                " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
3083                " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
3084                " free_cma:%lu\n",
3085                global_page_state(NR_ACTIVE_ANON),
3086                global_page_state(NR_INACTIVE_ANON),
3087                global_page_state(NR_ISOLATED_ANON),
3088                global_page_state(NR_ACTIVE_FILE),
3089                global_page_state(NR_INACTIVE_FILE),
3090                global_page_state(NR_ISOLATED_FILE),
3091                global_page_state(NR_UNEVICTABLE),
3092                global_page_state(NR_FILE_DIRTY),
3093                global_page_state(NR_WRITEBACK),
3094                global_page_state(NR_UNSTABLE_NFS),
3095                global_page_state(NR_FREE_PAGES),
3096                global_page_state(NR_SLAB_RECLAIMABLE),
3097                global_page_state(NR_SLAB_UNRECLAIMABLE),
3098                global_page_state(NR_FILE_MAPPED),
3099                global_page_state(NR_SHMEM),
3100                global_page_state(NR_PAGETABLE),
3101                global_page_state(NR_BOUNCE),
3102                global_page_state(NR_FREE_CMA_PAGES));
3103
3104        for_each_populated_zone(zone) {
3105                int i;
3106
3107                if (skip_free_areas_node(filter, zone_to_nid(zone)))
3108                        continue;
3109                show_node(zone);
3110                printk("%s"
3111                        " free:%lukB"
3112                        " min:%lukB"
3113                        " low:%lukB"
3114                        " high:%lukB"
3115                        " active_anon:%lukB"
3116                        " inactive_anon:%lukB"
3117                        " active_file:%lukB"
3118                        " inactive_file:%lukB"
3119                        " unevictable:%lukB"
3120                        " isolated(anon):%lukB"
3121                        " isolated(file):%lukB"
3122                        " present:%lukB"
3123                        " managed:%lukB"
3124                        " mlocked:%lukB"
3125                        " dirty:%lukB"
3126                        " writeback:%lukB"
3127                        " mapped:%lukB"
3128                        " shmem:%lukB"
3129                        " slab_reclaimable:%lukB"
3130                        " slab_unreclaimable:%lukB"
3131                        " kernel_stack:%lukB"
3132                        " pagetables:%lukB"
3133                        " unstable:%lukB"
3134                        " bounce:%lukB"
3135                        " free_cma:%lukB"
3136                        " writeback_tmp:%lukB"
3137                        " pages_scanned:%lu"
3138                        " all_unreclaimable? %s"
3139                        "\n",
3140                        zone->name,
3141                        K(zone_page_state(zone, NR_FREE_PAGES)),
3142                        K(min_wmark_pages(zone)),
3143                        K(low_wmark_pages(zone)),
3144                        K(high_wmark_pages(zone)),
3145                        K(zone_page_state(zone, NR_ACTIVE_ANON)),
3146                        K(zone_page_state(zone, NR_INACTIVE_ANON)),
3147                        K(zone_page_state(zone, NR_ACTIVE_FILE)),
3148                        K(zone_page_state(zone, NR_INACTIVE_FILE)),
3149                        K(zone_page_state(zone, NR_UNEVICTABLE)),
3150                        K(zone_page_state(zone, NR_ISOLATED_ANON)),
3151                        K(zone_page_state(zone, NR_ISOLATED_FILE)),
3152                        K(zone->present_pages),
3153                        K(zone->managed_pages),
3154                        K(zone_page_state(zone, NR_MLOCK)),
3155                        K(zone_page_state(zone, NR_FILE_DIRTY)),
3156                        K(zone_page_state(zone, NR_WRITEBACK)),
3157                        K(zone_page_state(zone, NR_FILE_MAPPED)),
3158                        K(zone_page_state(zone, NR_SHMEM)),
3159                        K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
3160                        K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
3161                        zone_page_state(zone, NR_KERNEL_STACK) *
3162                                THREAD_SIZE / 1024,
3163                        K(zone_page_state(zone, NR_PAGETABLE)),
3164                        K(zone_page_state(zone, NR_UNSTABLE_NFS)),
3165                        K(zone_page_state(zone, NR_BOUNCE)),
3166                        K(zone_page_state(zone, NR_FREE_CMA_PAGES)),
3167                        K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
3168                        zone->pages_scanned,
3169                        (!zone_reclaimable(zone) ? "yes" : "no")
3170                        );
3171                printk("lowmem_reserve[]:");
3172                for (i = 0; i < MAX_NR_ZONES; i++)
3173                        printk(" %lu", zone->lowmem_reserve[i]);
3174                printk("\n");
3175        }
3176
3177        for_each_populated_zone(zone) {
3178                unsigned long nr[MAX_ORDER], flags, order, total = 0;
3179                unsigned char types[MAX_ORDER];
3180
3181                if (skip_free_areas_node(filter, zone_to_nid(zone)))
3182                        continue;
3183                show_node(zone);
3184                printk("%s: ", zone->name);
3185
3186                spin_lock_irqsave(&zone->lock, flags);
3187                for (order = 0; order < MAX_ORDER; order++) {
3188                        struct free_area *area = &zone->free_area[order];
3189                        int type;
3190
3191                        nr[order] = area->nr_free;
3192                        total += nr[order] << order;
3193
3194                        types[order] = 0;
3195                        for (type = 0; type < MIGRATE_TYPES; type++) {
3196                                if (!list_empty(&area->free_list[type]))
3197                                        types[order] |= 1 << type;
3198                        }
3199                }
3200                spin_unlock_irqrestore(&zone->lock, flags);
3201                for (order = 0; order < MAX_ORDER; order++) {
3202                        printk("%lu*%lukB ", nr[order], K(1UL) << order);
3203                        if (nr[order])
3204                                show_migration_types(types[order]);
3205                }
3206                printk("= %lukB\n", K(total));
3207        }
3208
3209        hugetlb_show_meminfo();
3210
3211        printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
3212
3213        show_swap_cache_info();
3214}
3215
3216static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
3217{
3218        zoneref->zone = zone;
3219        zoneref->zone_idx = zone_idx(zone);
3220}
3221
3222/*
3223 * Builds allocation fallback zone lists.
3224 *
3225 * Add all populated zones of a node to the zonelist.
3226 */
3227static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
3228                                int nr_zones)
3229{
3230        struct zone *zone;
3231        enum zone_type zone_type = MAX_NR_ZONES;
3232
3233        do {
3234                zone_type--;
3235                zone = pgdat->node_zones + zone_type;
3236                if (populated_zone(zone)) {
3237                        zoneref_set_zone(zone,
3238                                &zonelist->_zonerefs[nr_zones++]);
3239                        check_highest_zone(zone_type);
3240                }
3241        } while (zone_type);
3242
3243        return nr_zones;
3244}
3245
3246
3247/*
3248 *  zonelist_order:
3249 *  0 = automatic detection of better ordering.
3250 *  1 = order by ([node] distance, -zonetype)
3251 *  2 = order by (-zonetype, [node] distance)
3252 *
3253 *  If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
3254 *  the same zonelist. So only NUMA can configure this param.
3255 */
3256#define ZONELIST_ORDER_DEFAULT  0
3257#define ZONELIST_ORDER_NODE     1
3258#define ZONELIST_ORDER_ZONE     2
3259
3260/* zonelist order in the kernel.
3261 * set_zonelist_order() will set this to NODE or ZONE.
3262 */
3263static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
3264static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
3265
3266
3267#ifdef CONFIG_NUMA
3268/* The value user specified ....changed by config */
3269static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
3270/* string for sysctl */
3271#define NUMA_ZONELIST_ORDER_LEN 16
3272char numa_zonelist_order[16] = "default";
3273
3274/*
3275 * interface for configure zonelist ordering.
3276 * command line option "numa_zonelist_order"
3277 *      = "[dD]efault   - default, automatic configuration.
3278 *      = "[nN]ode      - order by node locality, then by zone within node
3279 *      = "[zZ]one      - order by zone, then by locality within zone
3280 */
3281
3282static int __parse_numa_zonelist_order(char *s)
3283{
3284        if (*s == 'd' || *s == 'D') {
3285                user_zonelist_order = ZONELIST_ORDER_DEFAULT;
3286        } else if (*s == 'n' || *s == 'N') {
3287                user_zonelist_order = ZONELIST_ORDER_NODE;
3288        } else if (*s == 'z' || *s == 'Z') {
3289                user_zonelist_order = ZONELIST_ORDER_ZONE;
3290        } else {
3291                printk(KERN_WARNING
3292                        "Ignoring invalid numa_zonelist_order value:  "
3293                        "%s\n", s);
3294                return -EINVAL;
3295        }
3296        return 0;
3297}
3298
3299static __init int setup_numa_zonelist_order(char *s)
3300{
3301        int ret;
3302
3303        if (!s)
3304                return 0;
3305
3306        ret = __parse_numa_zonelist_order(s);
3307        if (ret == 0)
3308                strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
3309
3310        return ret;
3311}
3312early_param("numa_zonelist_order", setup_numa_zonelist_order);
3313
3314/*
3315 * sysctl handler for numa_zonelist_order
3316 */
3317int numa_zonelist_order_handler(ctl_table *table, int write,
3318                void __user *buffer, size_t *length,
3319                loff_t *ppos)
3320{
3321        char saved_string[NUMA_ZONELIST_ORDER_LEN];
3322        int ret;
3323        static DEFINE_MUTEX(zl_order_mutex);
3324
3325        mutex_lock(&zl_order_mutex);
3326        if (write) {
3327                if (strlen((char *)table->data) >= NUMA_ZONELIST_ORDER_LEN) {
3328                        ret = -EINVAL;
3329                        goto out;
3330                }
3331                strcpy(saved_string, (char *)table->data);
3332        }
3333        ret = proc_dostring(table, write, buffer, length, ppos);
3334        if (ret)
3335                goto out;
3336        if (write) {
3337                int oldval = user_zonelist_order;
3338
3339                ret = __parse_numa_zonelist_order((char *)table->data);
3340                if (ret) {
3341                        /*
3342                         * bogus value.  restore saved string
3343                         */
3344                        strncpy((char *)table->data, saved_string,
3345                                NUMA_ZONELIST_ORDER_LEN);
3346                        user_zonelist_order = oldval;
3347                } else if (oldval != user_zonelist_order) {
3348                        mutex_lock(&zonelists_mutex);
3349                        build_all_zonelists(NULL, NULL);
3350                        mutex_unlock(&zonelists_mutex);
3351                }
3352        }
3353out:
3354        mutex_unlock(&zl_order_mutex);
3355        return ret;
3356}
3357
3358
3359#define MAX_NODE_LOAD (nr_online_nodes)
3360static int node_load[MAX_NUMNODES];
3361
3362/**
3363 * find_next_best_node - find the next node that should appear in a given node's fallback list
3364 * @node: node whose fallback list we're appending
3365 * @used_node_mask: nodemask_t of already used nodes
3366 *
3367 * We use a number of factors to determine which is the next node that should
3368 * appear on a given node's fallback list.  The node should not have appeared
3369 * already in @node's fallback list, and it should be the next closest node
3370 * according to the distance array (which contains arbitrary distance values
3371 * from each node to each node in the system), and should also prefer nodes
3372 * with no CPUs, since presumably they'll have very little allocation pressure
3373 * on them otherwise.
3374 * It returns -1 if no node is found.
3375 */
3376static int find_next_best_node(int node, nodemask_t *used_node_mask)
3377{
3378        int n, val;
3379        int min_val = INT_MAX;
3380        int best_node = NUMA_NO_NODE;
3381        const struct cpumask *tmp = cpumask_of_node(0);
3382
3383        /* Use the local node if we haven't already */
3384        if (!node_isset(node, *used_node_mask)) {
3385                node_set(node, *used_node_mask);
3386                return node;
3387        }
3388
3389        for_each_node_state(n, N_MEMORY) {
3390
3391                /* Don't want a node to appear more than once */
3392                if (node_isset(n, *used_node_mask))
3393                        continue;
3394
3395                /* Use the distance array to find the distance */
3396                val = node_distance(node, n);
3397
3398                /* Penalize nodes under us ("prefer the next node") */
3399                val += (n < node);
3400
3401                /* Give preference to headless and unused nodes */
3402                tmp = cpumask_of_node(n);
3403                if (!cpumask_empty(tmp))
3404                        val += PENALTY_FOR_NODE_WITH_CPUS;
3405
3406                /* Slight preference for less loaded node */
3407                val *= (MAX_NODE_LOAD*MAX_NUMNODES);
3408                val += node_load[n];
3409
3410                if (val < min_val) {
3411                        min_val = val;
3412                        best_node = n;
3413                }
3414        }
3415
3416        if (best_node >= 0)
3417                node_set(best_node, *used_node_mask);
3418
3419        return best_node;
3420}
3421
3422
3423/*
3424 * Build zonelists ordered by node and zones within node.
3425 * This results in maximum locality--normal zone overflows into local
3426 * DMA zone, if any--but risks exhausting DMA zone.
3427 */
3428static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
3429{
3430        int j;
3431        struct zonelist *zonelist;
3432
3433        zonelist = &pgdat->node_zonelists[0];
3434        for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
3435                ;
3436        j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3437        zonelist->_zonerefs[j].zone = NULL;
3438        zonelist->_zonerefs[j].zone_idx = 0;
3439}
3440
3441/*
3442 * Build gfp_thisnode zonelists
3443 */
3444static void build_thisnode_zonelists(pg_data_t *pgdat)
3445{
3446        int j;
3447        struct zonelist *zonelist;
3448
3449        zonelist = &pgdat->node_zonelists[1];
3450        j = build_zonelists_node(pgdat, zonelist, 0);
3451        zonelist->_zonerefs[j].zone = NULL;
3452        zonelist->_zonerefs[j].zone_idx = 0;
3453}
3454
3455/*
3456 * Build zonelists ordered by zone and nodes within zones.
3457 * This results in conserving DMA zone[s] until all Normal memory is
3458 * exhausted, but results in overflowing to remote node while memory
3459 * may still exist in local DMA zone.
3460 */
3461static int node_order[MAX_NUMNODES];
3462
3463static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
3464{
3465        int pos, j, node;
3466        int zone_type;          /* needs to be signed */
3467        struct zone *z;
3468        struct zonelist *zonelist;
3469
3470        zonelist = &pgdat->node_zonelists[0];
3471        pos = 0;
3472        for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
3473                for (j = 0; j < nr_nodes; j++) {
3474                        node = node_order[j];
3475                        z = &NODE_DATA(node)->node_zones[zone_type];
3476                        if (populated_zone(z)) {
3477                                zoneref_set_zone(z,
3478                                        &zonelist->_zonerefs[pos++]);
3479                                check_highest_zone(zone_type);
3480                        }
3481                }
3482        }
3483        zonelist->_zonerefs[pos].zone = NULL;
3484        zonelist->_zonerefs[pos].zone_idx = 0;
3485}
3486
3487static int default_zonelist_order(void)
3488{
3489        int nid, zone_type;
3490        unsigned long low_kmem_size, total_size;
3491        struct zone *z;
3492        int average_size;
3493        /*
3494         * ZONE_DMA and ZONE_DMA32 can be very small area in the system.
3495         * If they are really small and used heavily, the system can fall
3496         * into OOM very easily.
3497         * This function detect ZONE_DMA/DMA32 size and configures zone order.
3498         */
3499        /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
3500        low_kmem_size = 0;
3501        total_size = 0;
3502        for_each_online_node(nid) {
3503                for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3504                        z = &NODE_DATA(nid)->node_zones[zone_type];
3505                        if (populated_zone(z)) {
3506                                if (zone_type < ZONE_NORMAL)
3507                                        low_kmem_size += z->managed_pages;
3508                                total_size += z->managed_pages;
3509                        } else if (zone_type == ZONE_NORMAL) {
3510                                /*
3511                                 * If any node has only lowmem, then node order
3512                                 * is preferred to allow kernel allocations
3513                                 * locally; otherwise, they can easily infringe
3514                                 * on other nodes when there is an abundance of
3515                                 * lowmem available to allocate from.
3516                                 */
3517                                return ZONELIST_ORDER_NODE;
3518                        }
3519                }
3520        }
3521        if (!low_kmem_size ||  /* there are no DMA area. */
3522            low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
3523                return ZONELIST_ORDER_NODE;
3524        /*
3525         * look into each node's config.
3526         * If there is a node whose DMA/DMA32 memory is very big area on
3527         * local memory, NODE_ORDER may be suitable.
3528         */
3529        average_size = total_size /
3530                                (nodes_weight(node_states[N_MEMORY]) + 1);
3531        for_each_online_node(nid) {
3532                low_kmem_size = 0;
3533                total_size = 0;
3534                for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3535                        z = &NODE_DATA(nid)->node_zones[zone_type];
3536                        if (populated_zone(z)) {
3537                                if (zone_type < ZONE_NORMAL)
3538                                        low_kmem_size += z->present_pages;
3539                                total_size += z->present_pages;
3540                        }
3541                }
3542                if (low_kmem_size &&
3543                    total_size > average_size && /* ignore small node */
3544                    low_kmem_size > total_size * 70/100)
3545                        return ZONELIST_ORDER_NODE;
3546        }
3547        return ZONELIST_ORDER_ZONE;
3548}
3549
3550static void set_zonelist_order(void)
3551{
3552        if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
3553                current_zonelist_order = default_zonelist_order();
3554        else
3555                current_zonelist_order = user_zonelist_order;
3556}
3557
3558static void build_zonelists(pg_data_t *pgdat)
3559{
3560        int j, node, load;
3561        enum zone_type i;
3562        nodemask_t used_mask;
3563        int local_node, prev_node;
3564        struct zonelist *zonelist;
3565        int order = current_zonelist_order;
3566
3567        /* initialize zonelists */
3568        for (i = 0; i < MAX_ZONELISTS; i++) {
3569                zonelist = pgdat->node_zonelists + i;
3570                zonelist->_zonerefs[0].zone = NULL;
3571                zonelist->_zonerefs[0].zone_idx = 0;
3572        }
3573
3574        /* NUMA-aware ordering of nodes */
3575        local_node = pgdat->node_id;
3576        load = nr_online_nodes;
3577        prev_node = local_node;
3578        nodes_clear(used_mask);
3579
3580        memset(node_order, 0, sizeof(node_order));
3581        j = 0;
3582
3583        while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
3584                /*
3585                 * We don't want to pressure a particular node.
3586                 * So adding penalty to the first node in same
3587                 * distance group to make it round-robin.
3588                 */
3589                if (node_distance(local_node, node) !=
3590                    node_distance(local_node, prev_node))
3591                        node_load[node] = load;
3592
3593                prev_node = node;
3594                load--;
3595                if (order == ZONELIST_ORDER_NODE)
3596                        build_zonelists_in_node_order(pgdat, node);
3597                else
3598                        node_order[j++] = node; /* remember order */
3599        }
3600
3601        if (order == ZONELIST_ORDER_ZONE) {
3602                /* calculate node order -- i.e., DMA last! */
3603                build_zonelists_in_zone_order(pgdat, j);
3604        }
3605
3606        build_thisnode_zonelists(pgdat);
3607}
3608
3609/* Construct the zonelist performance cache - see further mmzone.h */
3610static void build_zonelist_cache(pg_data_t *pgdat)
3611{
3612        struct zonelist *zonelist;
3613        struct zonelist_cache *zlc;
3614        struct zoneref *z;
3615
3616        zonelist = &pgdat->node_zonelists[0];
3617        zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
3618        bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
3619        for (z = zonelist->_zonerefs; z->zone; z++)
3620                zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
3621}
3622
3623#ifdef CONFIG_HAVE_MEMORYLESS_NODES
3624/*
3625 * Return node id of node used for "local" allocations.
3626 * I.e., first node id of first zone in arg node's generic zonelist.
3627 * Used for initializing percpu 'numa_mem', which is used primarily
3628 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
3629 */
3630int local_memory_node(int node)
3631{
3632        struct zone *zone;
3633
3634        (void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
3635                                   gfp_zone(GFP_KERNEL),
3636                                   NULL,
3637                                   &zone);
3638        return zone->node;
3639}
3640#endif
3641
3642#else   /* CONFIG_NUMA */
3643
3644static void set_zonelist_order(void)
3645{
3646        current_zonelist_order = ZONELIST_ORDER_ZONE;
3647}
3648
3649static void build_zonelists(pg_data_t *pgdat)
3650{
3651        int node, local_node;
3652        enum zone_type j;
3653        struct zonelist *zonelist;
3654
3655        local_node = pgdat->node_id;
3656
3657        zonelist = &pgdat->node_zonelists[0];
3658        j = build_zonelists_node(pgdat, zonelist, 0);
3659
3660        /*
3661         * Now we build the zonelist so that it contains the zones
3662         * of all the other nodes.
3663         * We don't want to pressure a particular node, so when
3664         * building the zones for node N, we make sure that the
3665         * zones coming right after the local ones are those from
3666         * node N+1 (modulo N)
3667         */
3668        for (node = local_node + 1; node < MAX_NUMNODES; node++) {
3669                if (!node_online(node))
3670                        continue;
3671                j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3672        }
3673        for (node = 0; node < local_node; node++) {
3674                if (!node_online(node))
3675                        continue;
3676                j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3677        }
3678
3679        zonelist->_zonerefs[j].zone = NULL;
3680        zonelist->_zonerefs[j].zone_idx = 0;
3681}
3682
3683/* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
3684static void build_zonelist_cache(pg_data_t *pgdat)
3685{
3686        pgdat->node_zonelists[0].zlcache_ptr = NULL;
3687}
3688
3689#endif  /* CONFIG_NUMA */
3690
3691/*
3692 * Boot pageset table. One per cpu which is going to be used for all
3693 * zones and all nodes. The parameters will be set in such a way
3694 * that an item put on a list will immediately be handed over to
3695 * the buddy list. This is safe since pageset manipulation is done
3696 * with interrupts disabled.
3697 *
3698 * The boot_pagesets must be kept even after bootup is complete for
3699 * unused processors and/or zones. They do play a role for bootstrapping
3700 * hotplugged processors.
3701 *
3702 * zoneinfo_show() and maybe other functions do
3703 * not check if the processor is online before following the pageset pointer.
3704 * Other parts of the kernel may not check if the zone is available.
3705 */
3706static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
3707static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
3708static void setup_zone_pageset(struct zone *zone);
3709
3710/*
3711 * Global mutex to protect against size modification of zonelists
3712 * as well as to serialize pageset setup for the new populated zone.
3713 */
3714DEFINE_MUTEX(zonelists_mutex);
3715
3716/* return values int ....just for stop_machine() */
3717static int __build_all_zonelists(void *data)
3718{
3719        int nid;
3720        int cpu;
3721        pg_data_t *self = data;
3722
3723#ifdef CONFIG_NUMA
3724        memset(node_load, 0, sizeof(node_load));
3725#endif
3726
3727        if (self && !node_online(self->node_id)) {
3728                build_zonelists(self);
3729                build_zonelist_cache(self);
3730        }
3731
3732        for_each_online_node(nid) {
3733                pg_data_t *pgdat = NODE_DATA(nid);
3734
3735                build_zonelists(pgdat);
3736                build_zonelist_cache(pgdat);
3737        }
3738
3739        /*
3740         * Initialize the boot_pagesets that are going to be used
3741         * for bootstrapping processors. The real pagesets for
3742         * each zone will be allocated later when the per cpu
3743         * allocator is available.
3744         *
3745         * boot_pagesets are used also for bootstrapping offline
3746         * cpus if the system is already booted because the pagesets
3747         * are needed to initialize allocators on a specific cpu too.
3748         * F.e. the percpu allocator needs the page allocator which
3749         * needs the percpu allocator in order to allocate its pagesets
3750         * (a chicken-egg dilemma).
3751         */
3752        for_each_possible_cpu(cpu) {
3753                setup_pageset(&per_cpu(boot_pageset, cpu), 0);
3754
3755#ifdef CONFIG_HAVE_MEMORYLESS_NODES
3756                /*
3757                 * We now know the "local memory node" for each node--
3758                 * i.e., the node of the first zone in the generic zonelist.
3759                 * Set up numa_mem percpu variable for on-line cpus.  During
3760                 * boot, only the boot cpu should be on-line;  we'll init the
3761                 * secondary cpus' numa_mem as they come on-line.  During
3762                 * node/memory hotplug, we'll fixup all on-line cpus.
3763                 */
3764                if (cpu_online(cpu))
3765                        set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
3766#endif
3767        }
3768
3769        return 0;
3770}
3771
3772/*
3773 * Called with zonelists_mutex held always
3774 * unless system_state == SYSTEM_BOOTING.
3775 */
3776void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone)
3777{
3778        set_zonelist_order();
3779
3780        if (system_state == SYSTEM_BOOTING) {
3781                __build_all_zonelists(NULL);
3782                mminit_verify_zonelist();
3783                cpuset_init_current_mems_allowed();
3784        } else {
3785#ifdef CONFIG_MEMORY_HOTPLUG
3786                if (zone)
3787                        setup_zone_pageset(zone);
3788#endif
3789                /* we have to stop all cpus to guarantee there is no user
3790                   of zonelist */
3791                stop_machine(__build_all_zonelists, pgdat, NULL);
3792                /* cpuset refresh routine should be here */
3793        }
3794        vm_total_pages = nr_free_pagecache_pages();
3795        /*
3796         * Disable grouping by mobility if the number of pages in the
3797         * system is too low to allow the mechanism to work. It would be
3798         * more accurate, but expensive to check per-zone. This check is
3799         * made on memory-hotadd so a system can start with mobility
3800         * disabled and enable it later
3801         */
3802        if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
3803                page_group_by_mobility_disabled = 1;
3804        else
3805                page_group_by_mobility_disabled = 0;
3806
3807        printk("Built %i zonelists in %s order, mobility grouping %s.  "
3808                "Total pages: %ld\n",
3809                        nr_online_nodes,
3810                        zonelist_order_name[current_zonelist_order],
3811                        page_group_by_mobility_disabled ? "off" : "on",
3812                        vm_total_pages);
3813#ifdef CONFIG_NUMA
3814        printk("Policy zone: %s\n", zone_names[policy_zone]);
3815#endif
3816}
3817
3818/*
3819 * Helper functions to size the waitqueue hash table.
3820 * Essentially these want to choose hash table sizes sufficiently
3821 * large so that collisions trying to wait on pages are rare.
3822 * But in fact, the number of active page waitqueues on typical
3823 * systems is ridiculously low, less than 200. So this is even
3824 * conservative, even though it seems large.
3825 *
3826 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
3827 * waitqueues, i.e. the size of the waitq table given the number of pages.
3828 */
3829#define PAGES_PER_WAITQUEUE     256
3830
3831#ifndef CONFIG_MEMORY_HOTPLUG
3832static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3833{
3834        unsigned long size = 1;
3835
3836        pages /= PAGES_PER_WAITQUEUE;
3837
3838        while (size < pages)
3839                size <<= 1;
3840
3841        /*
3842         * Once we have dozens or even hundreds of threads sleeping
3843         * on IO we've got bigger problems than wait queue collision.
3844         * Limit the size of the wait table to a reasonable size.
3845         */
3846        size = min(size, 4096UL);
3847
3848        return max(size, 4UL);
3849}
3850#else
3851/*
3852 * A zone's size might be changed by hot-add, so it is not possible to determine
3853 * a suitable size for its wait_table.  So we use the maximum size now.
3854 *
3855 * The max wait table size = 4096 x sizeof(wait_queue_head_t).   ie:
3856 *
3857 *    i386 (preemption config)    : 4096 x 16 = 64Kbyte.
3858 *    ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
3859 *    ia64, x86-64 (preemption)   : 4096 x 24 = 96Kbyte.
3860 *
3861 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
3862 * or more by the traditional way. (See above).  It equals:
3863 *
3864 *    i386, x86-64, powerpc(4K page size) : =  ( 2G + 1M)byte.
3865 *    ia64(16K page size)                 : =  ( 8G + 4M)byte.
3866 *    powerpc (64K page size)             : =  (32G +16M)byte.
3867 */
3868static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3869{
3870        return 4096UL;
3871}
3872#endif
3873
3874/*
3875 * This is an integer logarithm so that shifts can be used later
3876 * to extract the more random high bits from the multiplicative
3877 * hash function before the remainder is taken.
3878 */
3879static inline unsigned long wait_table_bits(unsigned long size)
3880{
3881        return ffz(~size);
3882}
3883
3884#define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
3885
3886/*
3887 * Check if a pageblock contains reserved pages
3888 */
3889static int pageblock_is_reserved(unsigned long start_pfn, unsigned long end_pfn)
3890{
3891        unsigned long pfn;
3892
3893        for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3894                if (!pfn_valid_within(pfn) || PageReserved(pfn_to_page(pfn)))
3895                        return 1;
3896        }
3897        return 0;
3898}
3899
3900/*
3901 * Mark a number of pageblocks as MIGRATE_RESERVE. The number
3902 * of blocks reserved is based on min_wmark_pages(zone). The memory within
3903 * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
3904 * higher will lead to a bigger reserve which will get freed as contiguous
3905 * blocks as reclaim kicks in
3906 */
3907static void setup_zone_migrate_reserve(struct zone *zone)
3908{
3909        unsigned long start_pfn, pfn, end_pfn, block_end_pfn;
3910        struct page *page;
3911        unsigned long block_migratetype;
3912        int reserve;
3913
3914        /*
3915         * Get the start pfn, end pfn and the number of blocks to reserve
3916         * We have to be careful to be aligned to pageblock_nr_pages to
3917         * make sure that we always check pfn_valid for the first page in
3918         * the block.
3919         */
3920        start_pfn = zone->zone_start_pfn;
3921        end_pfn = zone_end_pfn(zone);
3922        start_pfn = roundup(start_pfn, pageblock_nr_pages);
3923        reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
3924                                                        pageblock_order;
3925
3926        /*
3927         * Reserve blocks are generally in place to help high-order atomic
3928         * allocations that are short-lived. A min_free_kbytes value that
3929         * would result in more than 2 reserve blocks for atomic allocations
3930         * is assumed to be in place to help anti-fragmentation for the
3931         * future allocation of hugepages at runtime.
3932         */
3933        reserve = min(2, reserve);
3934
3935        for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
3936                if (!pfn_valid(pfn))
3937                        continue;
3938                page = pfn_to_page(pfn);
3939
3940                /* Watch out for overlapping nodes */
3941                if (page_to_nid(page) != zone_to_nid(zone))
3942                        continue;
3943
3944                block_migratetype = get_pageblock_migratetype(page);
3945
3946                /* Only test what is necessary when the reserves are not met */
3947                if (reserve > 0) {
3948                        /*
3949                         * Blocks with reserved pages will never free, skip
3950                         * them.
3951                         */
3952                        block_end_pfn = min(pfn + pageblock_nr_pages, end_pfn);
3953                        if (pageblock_is_reserved(pfn, block_end_pfn))
3954                                continue;
3955
3956                        /* If this block is reserved, account for it */
3957                        if (block_migratetype == MIGRATE_RESERVE) {
3958                                reserve--;
3959                                continue;
3960                        }
3961
3962                        /* Suitable for reserving if this block is movable */
3963                        if (block_migratetype == MIGRATE_MOVABLE) {
3964                                set_pageblock_migratetype(page,
3965                                                        MIGRATE_RESERVE);
3966                                move_freepages_block(zone, page,
3967                                                        MIGRATE_RESERVE);
3968                                reserve--;
3969                                continue;
3970                        }
3971                }
3972
3973                /*
3974                 * If the reserve is met and this is a previous reserved block,
3975                 * take it back
3976                 */
3977                if (block_migratetype == MIGRATE_RESERVE) {
3978                        set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3979                        move_freepages_block(zone, page, MIGRATE_MOVABLE);
3980                }
3981        }
3982}
3983
3984/*
3985 * Initially all pages are reserved - free ones are freed
3986 * up by free_all_bootmem() once the early boot process is
3987 * done. Non-atomic initialization, single-pass.
3988 */
3989void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
3990                unsigned long start_pfn, enum memmap_context context)
3991{
3992        struct page *page;
3993        unsigned long end_pfn = start_pfn + size;
3994        unsigned long pfn;
3995        struct zone *z;
3996
3997        if (highest_memmap_pfn < end_pfn - 1)
3998                highest_memmap_pfn = end_pfn - 1;
3999
4000        z = &NODE_DATA(nid)->node_zones[zone];
4001        for (pfn = start_pfn; pfn < end_pfn; pfn++) {
4002                /*
4003                 * There can be holes in boot-time mem_map[]s
4004                 * handed to this function.  They do not
4005                 * exist on hotplugged memory.
4006                 */
4007                if (context == MEMMAP_EARLY) {
4008                        if (!early_pfn_valid(pfn))
4009                                continue;
4010                        if (!early_pfn_in_nid(pfn, nid))
4011                                continue;
4012                }
4013                page = pfn_to_page(pfn);
4014                set_page_links(page, zone, nid, pfn);
4015                mminit_verify_page_links(page, zone, nid, pfn);
4016                init_page_count(page);
4017                page_mapcount_reset(page);
4018                page_nid_reset_last(page);
4019                SetPageReserved(page);
4020                /*
4021                 * Mark the block movable so that blocks are reserved for
4022                 * movable at startup. This will force kernel allocations
4023                 * to reserve their blocks rather than leaking throughout
4024                 * the address space during boot when many long-lived
4025                 * kernel allocations are made. Later some blocks near
4026                 * the start are marked MIGRATE_RESERVE by
4027                 * setup_zone_migrate_reserve()
4028                 *
4029                 * bitmap is created for zone's valid pfn range. but memmap
4030                 * can be created for invalid pages (for alignment)
4031                 * check here not to call set_pageblock_migratetype() against
4032                 * pfn out of zone.
4033                 */
4034                if ((z->zone_start_pfn <= pfn)
4035                    && (pfn < zone_end_pfn(z))
4036                    && !(pfn & (pageblock_nr_pages - 1)))
4037                        set_pageblock_migratetype(page, MIGRATE_MOVABLE);
4038
4039                INIT_LIST_HEAD(&page->lru);
4040#ifdef WANT_PAGE_VIRTUAL
4041                /* The shift won't overflow because ZONE_NORMAL is below 4G. */
4042                if (!is_highmem_idx(zone))
4043                        set_page_address(page, __va(pfn << PAGE_SHIFT));
4044#endif
4045        }
4046}
4047
4048static void __meminit zone_init_free_lists(struct zone *zone)
4049{
4050        int order, t;
4051        for_each_migratetype_order(order, t) {
4052                INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
4053                zone->free_area[order].nr_free = 0;
4054        }
4055}
4056
4057#ifndef __HAVE_ARCH_MEMMAP_INIT
4058#define memmap_init(size, nid, zone, start_pfn) \
4059        memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
4060#endif
4061
4062static int __meminit zone_batchsize(struct zone *zone)
4063{
4064#ifdef CONFIG_MMU
4065        int batch;
4066
4067        /*
4068         * The per-cpu-pages pools are set to around 1000th of the
4069         * size of the zone.  But no more than 1/2 of a meg.
4070         *
4071         * OK, so we don't know how big the cache is.  So guess.
4072         */
4073        batch = zone->managed_pages / 1024;
4074        if (batch * PAGE_SIZE > 512 * 1024)
4075                batch = (512 * 1024) / PAGE_SIZE;
4076        batch /= 4;             /* We effectively *= 4 below */
4077        if (batch < 1)
4078                batch = 1;
4079
4080        /*
4081         * Clamp the batch to a 2^n - 1 value. Having a power
4082         * of 2 value was found to be more likely to have
4083         * suboptimal cache aliasing properties in some cases.
4084         *
4085         * For example if 2 tasks are alternately allocating
4086         * batches of pages, one task can end up with a lot
4087         * of pages of one half of the possible page colors
4088         * and the other with pages of the other colors.
4089         */
4090        batch = rounddown_pow_of_two(batch + batch/2) - 1;
4091
4092        return batch;
4093
4094#else
4095        /* The deferral and batching of frees should be suppressed under NOMMU
4096         * conditions.
4097         *
4098         * The problem is that NOMMU needs to be able to allocate large chunks
4099         * of contiguous memory as there's no hardware page translation to
4100         * assemble apparent contiguous memory from discontiguous pages.
4101         *
4102         * Queueing large contiguous runs of pages for batching, however,
4103         * causes the pages to actually be freed in smaller chunks.  As there
4104         * can be a significant delay between the individual batches being
4105         * recycled, this leads to the once large chunks of space being
4106         * fragmented and becoming unavailable for high-order allocations.
4107         */
4108        return 0;
4109#endif
4110}
4111
4112/*
4113 * pcp->high and pcp->batch values are related and dependent on one another:
4114 * ->batch must never be higher then ->high.
4115 * The following function updates them in a safe manner without read side
4116 * locking.
4117 *
4118 * Any new users of pcp->batch and pcp->high should ensure they can cope with
4119 * those fields changing asynchronously (acording the the above rule).
4120 *
4121 * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
4122 * outside of boot time (or some other assurance that no concurrent updaters
4123 * exist).
4124 */
4125static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
4126                unsigned long batch)
4127{
4128       /* start with a fail safe value for batch */
4129        pcp->batch = 1;
4130        smp_wmb();
4131
4132       /* Update high, then batch, in order */
4133        pcp->high = high;
4134        smp_wmb();
4135
4136        pcp->batch = batch;
4137}
4138
4139/* a companion to pageset_set_high() */
4140static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
4141{
4142        pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
4143}
4144
4145static void pageset_init(struct per_cpu_pageset *p)
4146{
4147        struct per_cpu_pages *pcp;
4148        int migratetype;
4149
4150        memset(p, 0, sizeof(*p));
4151
4152        pcp = &p->pcp;
4153        pcp->count = 0;
4154        for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
4155                INIT_LIST_HEAD(&pcp->lists[migratetype]);
4156}
4157
4158static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
4159{
4160        pageset_init(p);
4161        pageset_set_batch(p, batch);
4162}
4163
4164/*
4165 * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
4166 * to the value high for the pageset p.
4167 */
4168static void pageset_set_high(struct per_cpu_pageset *p,
4169                                unsigned long high)
4170{
4171        unsigned long batch = max(1UL, high / 4);
4172        if ((high / 4) > (PAGE_SHIFT * 8))
4173                batch = PAGE_SHIFT * 8;
4174
4175        pageset_update(&p->pcp, high, batch);
4176}
4177
4178static void __meminit pageset_set_high_and_batch(struct zone *zone,
4179                struct per_cpu_pageset *pcp)
4180{
4181        if (percpu_pagelist_fraction)
4182                pageset_set_high(pcp,
4183                        (zone->managed_pages /
4184                                percpu_pagelist_fraction));
4185        else
4186                pageset_set_batch(pcp, zone_batchsize(zone));
4187}
4188
4189static void __meminit zone_pageset_init(struct zone *zone, int cpu)
4190{
4191        struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
4192
4193        pageset_init(pcp);
4194        pageset_set_high_and_batch(zone, pcp);
4195}
4196
4197static void __meminit setup_zone_pageset(struct zone *zone)
4198{
4199        int cpu;
4200        zone->pageset = alloc_percpu(struct per_cpu_pageset);
4201        for_each_possible_cpu(cpu)
4202                zone_pageset_init(zone, cpu);
4203}
4204
4205/*
4206 * Allocate per cpu pagesets and initialize them.
4207 * Before this call only boot pagesets were available.
4208 */
4209void __init setup_per_cpu_pageset(void)
4210{
4211        struct zone *zone;
4212
4213        for_each_populated_zone(zone)
4214                setup_zone_pageset(zone);
4215}
4216
4217static noinline __init_refok
4218int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
4219{
4220        int i;
4221        struct pglist_data *pgdat = zone->zone_pgdat;
4222        size_t alloc_size;
4223
4224        /*
4225         * The per-page waitqueue mechanism uses hashed waitqueues
4226         * per zone.
4227         */
4228        zone->wait_table_hash_nr_entries =
4229                 wait_table_hash_nr_entries(zone_size_pages);
4230        zone->wait_table_bits =
4231                wait_table_bits(zone->wait_table_hash_nr_entries);
4232        alloc_size = zone->wait_table_hash_nr_entries
4233                                        * sizeof(wait_queue_head_t);
4234
4235        if (!slab_is_available()) {
4236                zone->wait_table = (wait_queue_head_t *)
4237                        alloc_bootmem_node_nopanic(pgdat, alloc_size);
4238        } else {
4239                /*
4240                 * This case means that a zone whose size was 0 gets new memory
4241                 * via memory hot-add.
4242                 * But it may be the case that a new node was hot-added.  In
4243                 * this case vmalloc() will not be able to use this new node's
4244                 * memory - this wait_table must be initialized to use this new
4245                 * node itself as well.
4246                 * To use this new node's memory, further consideration will be
4247                 * necessary.
4248                 */
4249                zone->wait_table = vmalloc(alloc_size);
4250        }
4251        if (!zone->wait_table)
4252                return -ENOMEM;
4253
4254        for (i = 0; i < zone->wait_table_hash_nr_entries; ++i)
4255                init_waitqueue_head(zone->wait_table + i);
4256
4257        return 0;
4258}
4259
4260static __meminit void zone_pcp_init(struct zone *zone)
4261{
4262        /*
4263         * per cpu subsystem is not up at this point. The following code
4264         * relies on the ability of the linker to provide the
4265         * offset of a (static) per cpu variable into the per cpu area.
4266         */
4267        zone->pageset = &boot_pageset;
4268
4269        if (zone->present_pages)
4270                printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%u\n",
4271                        zone->name, zone->present_pages,
4272                                         zone_batchsize(zone));
4273}
4274
4275int __meminit init_currently_empty_zone(struct zone *zone,
4276                                        unsigned long zone_start_pfn,
4277                                        unsigned long size,
4278                                        enum memmap_context context)
4279{
4280        struct pglist_data *pgdat = zone->zone_pgdat;
4281        int ret;
4282        ret = zone_wait_table_init(zone, size);
4283        if (ret)
4284                return ret;
4285        pgdat->nr_zones = zone_idx(zone) + 1;
4286
4287        zone->zone_start_pfn = zone_start_pfn;
4288
4289        mminit_dprintk(MMINIT_TRACE, "memmap_init",
4290                        "Initialising map node %d zone %lu pfns %lu -> %lu\n",
4291                        pgdat->node_id,
4292                        (unsigned long)zone_idx(zone),
4293                        zone_start_pfn, (zone_start_pfn + size));
4294
4295        zone_init_free_lists(zone);
4296
4297        return 0;
4298}
4299
4300#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4301#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
4302/*
4303 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
4304 * Architectures may implement their own version but if add_active_range()
4305 * was used and there are no special requirements, this is a convenient
4306 * alternative
4307 */
4308int __meminit __early_pfn_to_nid(unsigned long pfn)
4309{
4310        unsigned long start_pfn, end_pfn;
4311        int nid;
4312        /*
4313         * NOTE: The following SMP-unsafe globals are only used early in boot
4314         * when the kernel is running single-threaded.
4315         */
4316        static unsigned long __meminitdata last_start_pfn, last_end_pfn;
4317        static int __meminitdata last_nid;
4318
4319        if (last_start_pfn <= pfn && pfn < last_end_pfn)
4320                return last_nid;
4321
4322        nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
4323        if (nid != -1) {
4324                last_start_pfn = start_pfn;
4325                last_end_pfn = end_pfn;
4326                last_nid = nid;
4327        }
4328
4329        return nid;
4330}
4331#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
4332
4333int __meminit early_pfn_to_nid(unsigned long pfn)
4334{
4335        int nid;
4336
4337        nid = __early_pfn_to_nid(pfn);
4338        if (nid >= 0)
4339                return nid;
4340        /* just returns 0 */
4341        return 0;
4342}
4343
4344#ifdef CONFIG_NODES_SPAN_OTHER_NODES
4345bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
4346{
4347        int nid;
4348
4349        nid = __early_pfn_to_nid(pfn);
4350        if (nid >= 0 && nid != node)
4351                return false;
4352        return true;
4353}
4354#endif
4355
4356/**
4357 * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
4358 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
4359 * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
4360 *
4361 * If an architecture guarantees that all ranges registered with
4362 * add_active_ranges() contain no holes and may be freed, this
4363 * this function may be used instead of calling free_bootmem() manually.
4364 */
4365void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
4366{
4367        unsigned long start_pfn, end_pfn;
4368        int i, this_nid;
4369
4370        for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
4371                start_pfn = min(start_pfn, max_low_pfn);
4372                end_pfn = min(end_pfn, max_low_pfn);
4373
4374                if (start_pfn < end_pfn)
4375                        free_bootmem_node(NODE_DATA(this_nid),
4376                                          PFN_PHYS(start_pfn),
4377                                          (end_pfn - start_pfn) << PAGE_SHIFT);
4378        }
4379}
4380
4381/**
4382 * sparse_memory_present_with_active_regions - Call memory_present for each active range
4383 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
4384 *
4385 * If an architecture guarantees that all ranges registered with
4386 * add_active_ranges() contain no holes and may be freed, this
4387 * function may be used instead of calling memory_present() manually.
4388 */
4389void __init sparse_memory_present_with_active_regions(int nid)
4390{
4391        unsigned long start_pfn, end_pfn;
4392        int i, this_nid;
4393
4394        for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
4395                memory_present(this_nid, start_pfn, end_pfn);
4396}
4397
4398/**
4399 * get_pfn_range_for_nid - Return the start and end page frames for a node
4400 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
4401 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
4402 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
4403 *
4404 * It returns the start and end page frame of a node based on information
4405 * provided by an arch calling add_active_range(). If called for a node
4406 * with no available memory, a warning is printed and the start and end
4407 * PFNs will be 0.
4408 */
4409void __meminit get_pfn_range_for_nid(unsigned int nid,
4410                        unsigned long *start_pfn, unsigned long *end_pfn)
4411{
4412        unsigned long this_start_pfn, this_end_pfn;
4413        int i;
4414
4415        *start_pfn = -1UL;
4416        *end_pfn = 0;
4417
4418        for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
4419                *start_pfn = min(*start_pfn, this_start_pfn);
4420                *end_pfn = max(*end_pfn, this_end_pfn);
4421        }
4422
4423        if (*start_pfn == -1UL)
4424                *start_pfn = 0;
4425}
4426
4427/*
4428 * This finds a zone that can be used for ZONE_MOVABLE pages. The
4429 * assumption is made that zones within a node are ordered in monotonic
4430 * increasing memory addresses so that the "highest" populated zone is used
4431 */
4432static void __init find_usable_zone_for_movable(void)
4433{
4434        int zone_index;
4435        for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
4436                if (zone_index == ZONE_MOVABLE)
4437                        continue;
4438
4439                if (arch_zone_highest_possible_pfn[zone_index] >
4440                                arch_zone_lowest_possible_pfn[zone_index])
4441                        break;
4442        }
4443
4444        VM_BUG_ON(zone_index == -1);
4445        movable_zone = zone_index;
4446}
4447
4448/*
4449 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
4450 * because it is sized independent of architecture. Unlike the other zones,
4451 * the starting point for ZONE_MOVABLE is not fixed. It may be different
4452 * in each node depending on the size of each node and how evenly kernelcore
4453 * is distributed. This helper function adjusts the zone ranges
4454 * provided by the architecture for a given node by using the end of the
4455 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
4456 * zones within a node are in order of monotonic increases memory addresses
4457 */
4458static void __meminit adjust_zone_range_for_zone_movable(int nid,
4459                                        unsigned long zone_type,
4460                                        unsigned long node_start_pfn,
4461                                        unsigned long node_end_pfn,
4462                                        unsigned long *zone_start_pfn,
4463                                        unsigned long *zone_end_pfn)
4464{
4465        /* Only adjust if ZONE_MOVABLE is on this node */
4466        if (zone_movable_pfn[nid]) {
4467                /* Size ZONE_MOVABLE */
4468                if (zone_type == ZONE_MOVABLE) {
4469                        *zone_start_pfn = zone_movable_pfn[nid];
4470                        *zone_end_pfn = min(node_end_pfn,
4471                                arch_zone_highest_possible_pfn[movable_zone]);
4472
4473                /* Adjust for ZONE_MOVABLE starting within this range */
4474                } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
4475                                *zone_end_pfn > zone_movable_pfn[nid]) {
4476                        *zone_end_pfn = zone_movable_pfn[nid];
4477
4478                /* Check if this whole range is within ZONE_MOVABLE */
4479                } else if (*zone_start_pfn >= zone_movable_pfn[nid])
4480                        *zone_start_pfn = *zone_end_pfn;
4481        }
4482}
4483
4484/*
4485 * Return the number of pages a zone spans in a node, including holes
4486 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
4487 */
4488static unsigned long __meminit zone_spanned_pages_in_node(int nid,
4489                                        unsigned long zone_type,
4490                                        unsigned long node_start_pfn,
4491                                        unsigned long node_end_pfn,
4492                                        unsigned long *ignored)
4493{
4494        unsigned long zone_start_pfn, zone_end_pfn;
4495
4496        /* Get the start and end of the zone */
4497        zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
4498        zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
4499        adjust_zone_range_for_zone_movable(nid, zone_type,
4500                                node_start_pfn, node_end_pfn,
4501                                &zone_start_pfn, &zone_end_pfn);
4502
4503        /* Check that this node has pages within the zone's required range */
4504        if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
4505                return 0;
4506
4507        /* Move the zone boundaries inside the node if necessary */
4508        zone_end_pfn = min(zone_end_pfn, node_end_pfn);
4509        zone_start_pfn = max(zone_start_pfn, node_start_pfn);
4510
4511        /* Return the spanned pages */
4512        return zone_end_pfn - zone_start_pfn;
4513}
4514
4515/*
4516 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
4517 * then all holes in the requested range will be accounted for.
4518 */
4519unsigned long __meminit __absent_pages_in_range(int nid,
4520                                unsigned long range_start_pfn,
4521                                unsigned long range_end_pfn)
4522{
4523        unsigned long nr_absent = range_end_pfn - range_start_pfn;
4524        unsigned long start_pfn, end_pfn;
4525        int i;
4526
4527        for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
4528                start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
4529                end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
4530                nr_absent -= end_pfn - start_pfn;
4531        }
4532        return nr_absent;
4533}
4534
4535/**
4536 * absent_pages_in_range - Return number of page frames in holes within a range
4537 * @start_pfn: The start PFN to start searching for holes
4538 * @end_pfn: The end PFN to stop searching for holes
4539 *
4540 * It returns the number of pages frames in memory holes within a range.
4541 */
4542unsigned long __init absent_pages_in_range(unsigned long start_pfn,
4543                                                        unsigned long end_pfn)
4544{
4545        return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
4546}
4547
4548/* Return the number of page frames in holes in a zone on a node */
4549static unsigned long __meminit zone_absent_pages_in_node(int nid,
4550                                        unsigned long zone_type,
4551                                        unsigned long node_start_pfn,
4552                                        unsigned long node_end_pfn,
4553                                        unsigned long *ignored)
4554{
4555        unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
4556        unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
4557        unsigned long zone_start_pfn, zone_end_pfn;
4558
4559        zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
4560        zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
4561
4562        adjust_zone_range_for_zone_movable(nid, zone_type,
4563                        node_start_pfn, node_end_pfn,
4564                        &zone_start_pfn, &zone_end_pfn);
4565        return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
4566}
4567
4568#else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4569static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
4570                                        unsigned long zone_type,
4571                                        unsigned long node_start_pfn,
4572                                        unsigned long node_end_pfn,
4573                                        unsigned long *zones_size)
4574{
4575        return zones_size[zone_type];
4576}
4577
4578static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
4579                                                unsigned long zone_type,
4580                                                unsigned long node_start_pfn,
4581                                                unsigned long node_end_pfn,
4582                                                unsigned long *zholes_size)
4583{
4584        if (!zholes_size)
4585                return 0;
4586
4587        return zholes_size[zone_type];
4588}
4589
4590#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4591
4592static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
4593                                                unsigned long node_start_pfn,
4594                                                unsigned long node_end_pfn,
4595                                                unsigned long *zones_size,
4596                                                unsigned long *zholes_size)
4597{
4598        unsigned long realtotalpages, totalpages = 0;
4599        enum zone_type i;
4600
4601        for (i = 0; i < MAX_NR_ZONES; i++)
4602                totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
4603                                                         node_start_pfn,
4604                                                         node_end_pfn,
4605                                                         zones_size);
4606        pgdat->node_spanned_pages = totalpages;
4607
4608        realtotalpages = totalpages;
4609        for (i = 0; i < MAX_NR_ZONES; i++)
4610                realtotalpages -=
4611                        zone_absent_pages_in_node(pgdat->node_id, i,
4612                                                  node_start_pfn, node_end_pfn,
4613                                                  zholes_size);
4614        pgdat->node_present_pages = realtotalpages;
4615        printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
4616                                                        realtotalpages);
4617}
4618
4619#ifndef CONFIG_SPARSEMEM
4620/*
4621 * Calculate the size of the zone->blockflags rounded to an unsigned long
4622 * Start by making sure zonesize is a multiple of pageblock_order by rounding
4623 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
4624 * round what is now in bits to nearest long in bits, then return it in
4625 * bytes.
4626 */
4627static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
4628{
4629        unsigned long usemapsize;
4630
4631        zonesize += zone_start_pfn & (pageblock_nr_pages-1);
4632        usemapsize = roundup(zonesize, pageblock_nr_pages);
4633        usemapsize = usemapsize >> pageblock_order;
4634        usemapsize *= NR_PAGEBLOCK_BITS;
4635        usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
4636
4637        return usemapsize / 8;
4638}
4639
4640static void __init setup_usemap(struct pglist_data *pgdat,
4641                                struct zone *zone,
4642                                unsigned long zone_start_pfn,
4643                                unsigned long zonesize)
4644{
4645        unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
4646        zone->pageblock_flags = NULL;
4647        if (usemapsize)
4648                zone->pageblock_flags = alloc_bootmem_node_nopanic(pgdat,
4649                                                                   usemapsize);
4650}
4651#else
4652static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
4653                                unsigned long zone_start_pfn, unsigned long zonesize) {}
4654#endif /* CONFIG_SPARSEMEM */
4655
4656#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
4657
4658/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
4659void __paginginit set_pageblock_order(void)
4660{
4661        unsigned int order;
4662
4663        /* Check that pageblock_nr_pages has not already been setup */
4664        if (pageblock_order)
4665                return;
4666
4667        if (HPAGE_SHIFT > PAGE_SHIFT)
4668                order = HUGETLB_PAGE_ORDER;
4669        else
4670                order = MAX_ORDER - 1;
4671
4672        /*
4673         * Assume the largest contiguous order of interest is a huge page.
4674         * This value may be variable depending on boot parameters on IA64 and
4675         * powerpc.
4676         */
4677        pageblock_order = order;
4678}
4679#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4680
4681/*
4682 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
4683 * is unused as pageblock_order is set at compile-time. See
4684 * include/linux/pageblock-flags.h for the values of pageblock_order based on
4685 * the kernel config
4686 */
4687void __paginginit set_pageblock_order(void)
4688{
4689}
4690
4691#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4692
4693static unsigned long __paginginit calc_memmap_size(unsigned long spanned_pages,
4694                                                   unsigned long present_pages)
4695{
4696        unsigned long pages = spanned_pages;
4697
4698        /*
4699         * Provide a more accurate estimation if there are holes within
4700         * the zone and SPARSEMEM is in use. If there are holes within the
4701         * zone, each populated memory region may cost us one or two extra
4702         * memmap pages due to alignment because memmap pages for each
4703         * populated regions may not naturally algined on page boundary.
4704         * So the (present_pages >> 4) heuristic is a tradeoff for that.
4705         */
4706        if (spanned_pages > present_pages + (present_pages >> 4) &&
4707            IS_ENABLED(CONFIG_SPARSEMEM))
4708                pages = present_pages;
4709
4710        return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
4711}
4712
4713/*
4714 * Set up the zone data structures:
4715 *   - mark all pages reserved
4716 *   - mark all memory queues empty
4717 *   - clear the memory bitmaps
4718 *
4719 * NOTE: pgdat should get zeroed by caller.
4720 */
4721static void __paginginit free_area_init_core(struct pglist_data *pgdat,
4722                unsigned long node_start_pfn, unsigned long node_end_pfn,
4723                unsigned long *zones_size, unsigned long *zholes_size)
4724{
4725        enum zone_type j;
4726        int nid = pgdat->node_id;
4727        unsigned long zone_start_pfn = pgdat->node_start_pfn;
4728        int ret;
4729
4730        pgdat_resize_init(pgdat);
4731#ifdef CONFIG_NUMA_BALANCING
4732        spin_lock_init(&pgdat->numabalancing_migrate_lock);
4733        pgdat->numabalancing_migrate_nr_pages = 0;
4734        pgdat->numabalancing_migrate_next_window = jiffies;
4735#endif
4736        init_waitqueue_head(&pgdat->kswapd_wait);
4737        init_waitqueue_head(&pgdat->pfmemalloc_wait);
4738        pgdat_page_cgroup_init(pgdat);
4739
4740        for (j = 0; j < MAX_NR_ZONES; j++) {
4741                struct zone *zone = pgdat->node_zones + j;
4742                unsigned long size, realsize, freesize, memmap_pages;
4743
4744                size = zone_spanned_pages_in_node(nid, j, node_start_pfn,
4745                                                  node_end_pfn, zones_size);
4746                realsize = freesize = size - zone_absent_pages_in_node(nid, j,
4747                                                                node_start_pfn,
4748                                                                node_end_pfn,
4749                                                                zholes_size);
4750
4751                /*
4752                 * Adjust freesize so that it accounts for how much memory
4753                 * is used by this zone for memmap. This affects the watermark
4754                 * and per-cpu initialisations
4755                 */
4756                memmap_pages = calc_memmap_size(size, realsize);
4757                if (freesize >= memmap_pages) {
4758                        freesize -= memmap_pages;
4759                        if (memmap_pages)
4760                                printk(KERN_DEBUG
4761                                       "  %s zone: %lu pages used for memmap\n",
4762                                       zone_names[j], memmap_pages);
4763                } else
4764                        printk(KERN_WARNING
4765                                "  %s zone: %lu pages exceeds freesize %lu\n",
4766                                zone_names[j], memmap_pages, freesize);
4767
4768                /* Account for reserved pages */
4769                if (j == 0 && freesize > dma_reserve) {
4770                        freesize -= dma_reserve;
4771                        printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
4772                                        zone_names[0], dma_reserve);
4773                }
4774
4775                if (!is_highmem_idx(j))
4776                        nr_kernel_pages += freesize;
4777                /* Charge for highmem memmap if there are enough kernel pages */
4778                else if (nr_kernel_pages > memmap_pages * 2)
4779                        nr_kernel_pages -= memmap_pages;
4780                nr_all_pages += freesize;
4781
4782                zone->spanned_pages = size;
4783                zone->present_pages = realsize;
4784                /*
4785                 * Set an approximate value for lowmem here, it will be adjusted
4786                 * when the bootmem allocator frees pages into the buddy system.
4787                 * And all highmem pages will be managed by the buddy system.
4788                 */
4789                zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
4790#ifdef CONFIG_NUMA
4791                zone->node = nid;
4792                zone->min_unmapped_pages = (freesize*sysctl_min_unmapped_ratio)
4793                                                / 100;
4794                zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100;
4795#endif
4796                zone->name = zone_names[j];
4797                spin_lock_init(&zone->lock);
4798                spin_lock_init(&zone->lru_lock);
4799                zone_seqlock_init(zone);
4800                zone->zone_pgdat = pgdat;
4801                zone_pcp_init(zone);
4802
4803                /* For bootup, initialized properly in watermark setup */
4804                mod_zone_page_state(zone, NR_ALLOC_BATCH, zone->managed_pages);
4805
4806                lruvec_init(&zone->lruvec);
4807                if (!size)
4808                        continue;
4809
4810                set_pageblock_order();
4811                setup_usemap(pgdat, zone, zone_start_pfn, size);
4812                ret = init_currently_empty_zone(zone, zone_start_pfn,
4813                                                size, MEMMAP_EARLY);
4814                BUG_ON(ret);
4815                memmap_init(size, nid, j, zone_start_pfn);
4816                zone_start_pfn += size;
4817        }
4818}
4819
4820static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
4821{
4822        /* Skip empty nodes */
4823        if (!pgdat->node_spanned_pages)
4824                return;
4825
4826#ifdef CONFIG_FLAT_NODE_MEM_MAP
4827        /* ia64 gets its own node_mem_map, before this, without bootmem */
4828        if (!pgdat->node_mem_map) {
4829                unsigned long size, start, end;
4830                struct page *map;
4831
4832                /*
4833                 * The zone's endpoints aren't required to be MAX_ORDER
4834                 * aligned but the node_mem_map endpoints must be in order
4835                 * for the buddy allocator to function correctly.
4836                 */
4837                start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
4838                end = pgdat_end_pfn(pgdat);
4839                end = ALIGN(end, MAX_ORDER_NR_PAGES);
4840                size =  (end - start) * sizeof(struct page);
4841                map = alloc_remap(pgdat->node_id, size);
4842                if (!map)
4843                        map = alloc_bootmem_node_nopanic(pgdat, size);
4844                pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
4845        }
4846#ifndef CONFIG_NEED_MULTIPLE_NODES
4847        /*
4848         * With no DISCONTIG, the global mem_map is just set as node 0's
4849         */
4850        if (pgdat == NODE_DATA(0)) {
4851                mem_map = NODE_DATA(0)->node_mem_map;
4852#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4853                if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
4854                        mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
4855#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4856        }
4857#endif
4858#endif /* CONFIG_FLAT_NODE_MEM_MAP */
4859}
4860
4861void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
4862                unsigned long node_start_pfn, unsigned long *zholes_size)
4863{
4864        pg_data_t *pgdat = NODE_DATA(nid);
4865        unsigned long start_pfn = 0;
4866        unsigned long end_pfn = 0;
4867
4868        /* pg_data_t should be reset to zero when it's allocated */
4869        WARN_ON(pgdat->nr_zones || pgdat->classzone_idx);
4870
4871        pgdat->node_id = nid;
4872        pgdat->node_start_pfn = node_start_pfn;
4873        init_zone_allows_reclaim(nid);
4874#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4875        get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
4876#endif
4877        calculate_node_totalpages(pgdat, start_pfn, end_pfn,
4878                                  zones_size, zholes_size);
4879
4880        alloc_node_mem_map(pgdat);
4881#ifdef CONFIG_FLAT_NODE_MEM_MAP
4882        printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
4883                nid, (unsigned long)pgdat,
4884                (unsigned long)pgdat->node_mem_map);
4885#endif
4886
4887        free_area_init_core(pgdat, start_pfn, end_pfn,
4888                            zones_size, zholes_size);
4889}
4890
4891#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4892
4893#if MAX_NUMNODES > 1
4894/*
4895 * Figure out the number of possible node ids.
4896 */
4897void __init setup_nr_node_ids(void)
4898{
4899        unsigned int node;
4900        unsigned int highest = 0;
4901
4902        for_each_node_mask(node, node_possible_map)
4903                highest = node;
4904        nr_node_ids = highest + 1;
4905}
4906#endif
4907
4908/**
4909 * node_map_pfn_alignment - determine the maximum internode alignment
4910 *
4911 * This function should be called after node map is populated and sorted.
4912 * It calculates the maximum power of two alignment which can distinguish
4913 * all the nodes.
4914 *
4915 * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
4916 * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)).  If the
4917 * nodes are shifted by 256MiB, 256MiB.  Note that if only the last node is
4918 * shifted, 1GiB is enough and this function will indicate so.
4919 *
4920 * This is used to test whether pfn -> nid mapping of the chosen memory
4921 * model has fine enough granularity to avoid incorrect mapping for the
4922 * populated node map.
4923 *
4924 * Returns the determined alignment in pfn's.  0 if there is no alignment
4925 * requirement (single node).
4926 */
4927unsigned long __init node_map_pfn_alignment(void)
4928{
4929        unsigned long accl_mask = 0, last_end = 0;
4930        unsigned long start, end, mask;
4931        int last_nid = -1;
4932        int i, nid;
4933
4934        for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
4935                if (!start || last_nid < 0 || last_nid == nid) {
4936                        last_nid = nid;
4937                        last_end = end;
4938                        continue;
4939                }
4940
4941                /*
4942                 * Start with a mask granular enough to pin-point to the
4943                 * start pfn and tick off bits one-by-one until it becomes
4944                 * too coarse to separate the current node from the last.
4945                 */
4946                mask = ~((1 << __ffs(start)) - 1);
4947                while (mask && last_end <= (start & (mask << 1)))
4948                        mask <<= 1;
4949
4950                /* accumulate all internode masks */
4951                accl_mask |= mask;
4952        }
4953
4954        /* convert mask to number of pages */
4955        return ~accl_mask + 1;
4956}
4957
4958/* Find the lowest pfn for a node */
4959static unsigned long __init find_min_pfn_for_node(int nid)
4960{
4961        unsigned long min_pfn = ULONG_MAX;
4962        unsigned long start_pfn;
4963        int i;
4964
4965        for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
4966                min_pfn = min(min_pfn, start_pfn);
4967
4968        if (min_pfn == ULONG_MAX) {
4969                printk(KERN_WARNING
4970                        "Could not find start_pfn for node %d\n", nid);
4971                return 0;
4972        }
4973
4974        return min_pfn;
4975}
4976
4977/**
4978 * find_min_pfn_with_active_regions - Find the minimum PFN registered
4979 *
4980 * It returns the minimum PFN based on information provided via
4981 * add_active_range().
4982 */
4983unsigned long __init find_min_pfn_with_active_regions(void)
4984{
4985        return find_min_pfn_for_node(MAX_NUMNODES);
4986}
4987
4988/*
4989 * early_calculate_totalpages()
4990 * Sum pages in active regions for movable zone.
4991 * Populate N_MEMORY for calculating usable_nodes.
4992 */
4993static unsigned long __init early_calculate_totalpages(void)
4994{
4995        unsigned long totalpages = 0;
4996        unsigned long start_pfn, end_pfn;
4997        int i, nid;
4998
4999        for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
5000                unsigned long pages = end_pfn - start_pfn;
5001
5002                totalpages += pages;
5003                if (pages)
5004                        node_set_state(nid, N_MEMORY);
5005        }
5006        return totalpages;
5007}
5008
5009/*
5010 * Find the PFN the Movable zone begins in each node. Kernel memory
5011 * is spread evenly between nodes as long as the nodes have enough
5012 * memory. When they don't, some nodes will have more kernelcore than
5013 * others
5014 */
5015static void __init find_zone_movable_pfns_for_nodes(void)
5016{
5017        int i, nid;
5018        unsigned long usable_startpfn;
5019        unsigned long kernelcore_node, kernelcore_remaining;
5020        /* save the state before borrow the nodemask */
5021        nodemask_t saved_node_state = node_states[N_MEMORY];
5022        unsigned long totalpages = early_calculate_totalpages();
5023        int usable_nodes = nodes_weight(node_states[N_MEMORY]);
5024
5025        /*
5026         * If movablecore was specified, calculate what size of
5027         * kernelcore that corresponds so that memory usable for
5028         * any allocation type is evenly spread. If both kernelcore
5029         * and movablecore are specified, then the value of kernelcore
5030         * will be used for required_kernelcore if it's greater than
5031         * what movablecore would have allowed.
5032         */
5033        if (required_movablecore) {
5034                unsigned long corepages;
5035
5036                /*
5037                 * Round-up so that ZONE_MOVABLE is at least as large as what
5038                 * was requested by the user
5039                 */
5040                required_movablecore =
5041                        roundup(required_movablecore, MAX_ORDER_NR_PAGES);
5042                corepages = totalpages - required_movablecore;
5043
5044                required_kernelcore = max(required_kernelcore, corepages);
5045        }
5046
5047        /* If kernelcore was not specified, there is no ZONE_MOVABLE */
5048        if (!required_kernelcore)
5049                goto out;
5050
5051        /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
5052        find_usable_zone_for_movable();
5053        usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
5054
5055restart:
5056        /* Spread kernelcore memory as evenly as possible throughout nodes */
5057        kernelcore_node = required_kernelcore / usable_nodes;
5058        for_each_node_state(nid, N_MEMORY) {
5059                unsigned long start_pfn, end_pfn;
5060
5061                /*
5062                 * Recalculate kernelcore_node if the division per node
5063                 * now exceeds what is necessary to satisfy the requested
5064                 * amount of memory for the kernel
5065                 */
5066                if (required_kernelcore < kernelcore_node)
5067                        kernelcore_node = required_kernelcore / usable_nodes;
5068
5069                /*
5070                 * As the map is walked, we track how much memory is usable
5071                 * by the kernel using kernelcore_remaining. When it is
5072                 * 0, the rest of the node is usable by ZONE_MOVABLE
5073                 */
5074                kernelcore_remaining = kernelcore_node;
5075
5076                /* Go through each range of PFNs within this node */
5077                for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
5078                        unsigned long size_pages;
5079
5080                        start_pfn = max(start_pfn, zone_movable_pfn[nid]);
5081                        if (start_pfn >= end_pfn)
5082                                continue;
5083
5084                        /* Account for what is only usable for kernelcore */
5085                        if (start_pfn < usable_startpfn) {
5086                                unsigned long kernel_pages;
5087                                kernel_pages = min(end_pfn, usable_startpfn)
5088                                                                - start_pfn;
5089
5090                                kernelcore_remaining -= min(kernel_pages,
5091                                                        kernelcore_remaining);
5092                                required_kernelcore -= min(kernel_pages,
5093                                                        required_kernelcore);
5094
5095                                /* Continue if range is now fully accounted */
5096                                if (end_pfn <= usable_startpfn) {
5097
5098                                        /*
5099                                         * Push zone_movable_pfn to the end so
5100                                         * that if we have to rebalance
5101                                         * kernelcore across nodes, we will
5102                                         * not double account here
5103                                         */
5104                                        zone_movable_pfn[nid] = end_pfn;
5105                                        continue;
5106                                }
5107                                start_pfn = usable_startpfn;
5108                        }
5109
5110                        /*
5111                         * The usable PFN range for ZONE_MOVABLE is from
5112                         * start_pfn->end_pfn. Calculate size_pages as the
5113                         * number of pages used as kernelcore
5114                         */
5115                        size_pages = end_pfn - start_pfn;
5116                        if (size_pages > kernelcore_remaining)
5117                                size_pages = kernelcore_remaining;
5118                        zone_movable_pfn[nid] = start_pfn + size_pages;
5119
5120                        /*
5121                         * Some kernelcore has been met, update counts and
5122                         * break if the kernelcore for this node has been
5123                         * satisfied
5124                         */
5125                        required_kernelcore -= min(required_kernelcore,
5126                                                                size_pages);
5127                        kernelcore_remaining -= size_pages;
5128                        if (!kernelcore_remaining)
5129                                break;
5130                }
5131        }
5132
5133        /*
5134         * If there is still required_kernelcore, we do another pass with one
5135         * less node in the count. This will push zone_movable_pfn[nid] further
5136         * along on the nodes that still have memory until kernelcore is
5137         * satisfied
5138         */
5139        usable_nodes--;
5140        if (usable_nodes && required_kernelcore > usable_nodes)
5141                goto restart;
5142
5143        /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
5144        for (nid = 0; nid < MAX_NUMNODES; nid++)
5145                zone_movable_pfn[nid] =
5146                        roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
5147
5148out:
5149        /* restore the node_state */
5150        node_states[N_MEMORY] = saved_node_state;
5151}
5152
5153/* Any regular or high memory on that node ? */
5154static void check_for_memory(pg_data_t *pgdat, int nid)
5155{
5156        enum zone_type zone_type;
5157
5158        if (N_MEMORY == N_NORMAL_MEMORY)
5159                return;
5160
5161        for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
5162                struct zone *zone = &pgdat->node_zones[zone_type];
5163                if (zone->present_pages) {
5164                        node_set_state(nid, N_HIGH_MEMORY);
5165                        if (N_NORMAL_MEMORY != N_HIGH_MEMORY &&
5166                            zone_type <= ZONE_NORMAL)
5167                                node_set_state(nid, N_NORMAL_MEMORY);
5168                        break;
5169                }
5170        }
5171}
5172
5173/**
5174 * free_area_init_nodes - Initialise all pg_data_t and zone data
5175 * @max_zone_pfn: an array of max PFNs for each zone
5176 *
5177 * This will call free_area_init_node() for each active node in the system.
5178 * Using the page ranges provided by add_active_range(), the size of each
5179 * zone in each node and their holes is calculated. If the maximum PFN
5180 * between two adjacent zones match, it is assumed that the zone is empty.
5181 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
5182 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
5183 * starts where the previous one ended. For example, ZONE_DMA32 starts
5184 * at arch_max_dma_pfn.
5185 */
5186void __init free_area_init_nodes(unsigned long *max_zone_pfn)
5187{
5188        unsigned long start_pfn, end_pfn;
5189        int i, nid;
5190
5191        /* Record where the zone boundaries are */
5192        memset(arch_zone_lowest_possible_pfn, 0,
5193                                sizeof(arch_zone_lowest_possible_pfn));
5194        memset(arch_zone_highest_possible_pfn, 0,
5195                                sizeof(arch_zone_highest_possible_pfn));
5196        arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
5197        arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
5198        for (i = 1; i < MAX_NR_ZONES; i++) {
5199                if (i == ZONE_MOVABLE)
5200                        continue;
5201                arch_zone_lowest_possible_pfn[i] =
5202                        arch_zone_highest_possible_pfn[i-1];
5203                arch_zone_highest_possible_pfn[i] =
5204                        max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
5205        }
5206        arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
5207        arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
5208
5209        /* Find the PFNs that ZONE_MOVABLE begins at in each node */
5210        memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
5211        find_zone_movable_pfns_for_nodes();
5212
5213        /* Print out the zone ranges */
5214        printk("Zone ranges:\n");
5215        for (i = 0; i < MAX_NR_ZONES; i++) {
5216                if (i == ZONE_MOVABLE)
5217                        continue;
5218                printk(KERN_CONT "  %-8s ", zone_names[i]);
5219                if (arch_zone_lowest_possible_pfn[i] ==
5220                                arch_zone_highest_possible_pfn[i])
5221                        printk(KERN_CONT "empty\n");
5222                else
5223                        printk(KERN_CONT "[mem %0#10lx-%0#10lx]\n",
5224                                arch_zone_lowest_possible_pfn[i] << PAGE_SHIFT,
5225                                (arch_zone_highest_possible_pfn[i]
5226                                        << PAGE_SHIFT) - 1);
5227        }
5228
5229        /* Print out the PFNs ZONE_MOVABLE begins at in each node */
5230        printk("Movable zone start for each node\n");
5231        for (i = 0; i < MAX_NUMNODES; i++) {
5232                if (zone_movable_pfn[i])
5233                        printk("  Node %d: %#010lx\n", i,
5234                               zone_movable_pfn[i] << PAGE_SHIFT);
5235        }
5236
5237        /* Print out the early node map */
5238        printk("Early memory node ranges\n");
5239        for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
5240                printk("  node %3d: [mem %#010lx-%#010lx]\n", nid,
5241                       start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1);
5242
5243        /* Initialise every node */
5244        mminit_verify_pageflags_layout();
5245        setup_nr_node_ids();
5246        for_each_online_node(nid) {
5247                pg_data_t *pgdat = NODE_DATA(nid);
5248                free_area_init_node(nid, NULL,
5249                                find_min_pfn_for_node(nid), NULL);
5250
5251                /* Any memory on that node */
5252                if (pgdat->node_present_pages)
5253                        node_set_state(nid, N_MEMORY);
5254                check_for_memory(pgdat, nid);
5255        }
5256}
5257
5258static int __init cmdline_parse_core(char *p, unsigned long *core)
5259{
5260        unsigned long long coremem;
5261        if (!p)
5262                return -EINVAL;
5263
5264        coremem = memparse(p, &p);
5265        *core = coremem >> PAGE_SHIFT;
5266
5267        /* Paranoid check that UL is enough for the coremem value */
5268        WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
5269
5270        return 0;
5271}
5272
5273/*
5274 * kernelcore=size sets the amount of memory for use for allocations that
5275 * cannot be reclaimed or migrated.
5276 */
5277static int __init cmdline_parse_kernelcore(char *p)
5278{
5279        return cmdline_parse_core(p, &required_kernelcore);
5280}
5281
5282/*
5283 * movablecore=size sets the amount of memory for use for allocations that
5284 * can be reclaimed or migrated.
5285 */
5286static int __init cmdline_parse_movablecore(char *p)
5287{
5288        return cmdline_parse_core(p, &required_movablecore);
5289}
5290
5291early_param("kernelcore", cmdline_parse_kernelcore);
5292early_param("movablecore", cmdline_parse_movablecore);
5293
5294#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5295
5296void adjust_managed_page_count(struct page *page, long count)
5297{
5298        spin_lock(&managed_page_count_lock);
5299        page_zone(page)->managed_pages += count;
5300        totalram_pages += count;
5301#ifdef CONFIG_HIGHMEM
5302        if (PageHighMem(page))
5303                totalhigh_pages += count;
5304#endif
5305        spin_unlock(&managed_page_count_lock);
5306}
5307EXPORT_SYMBOL(adjust_managed_page_count);
5308
5309unsigned long free_reserved_area(void *start, void *end, int poison, char *s)
5310{
5311        void *pos;
5312        unsigned long pages = 0;
5313
5314        start = (void *)PAGE_ALIGN((unsigned long)start);
5315        end = (void *)((unsigned long)end & PAGE_MASK);
5316        for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
5317                if ((unsigned int)poison <= 0xFF)
5318                        memset(pos, poison, PAGE_SIZE);
5319                free_reserved_page(virt_to_page(pos));
5320        }
5321
5322        if (pages && s)
5323                pr_info("Freeing %s memory: %ldK (%p - %p)\n",
5324                        s, pages << (PAGE_SHIFT - 10), start, end);
5325
5326        return pages;
5327}
5328EXPORT_SYMBOL(free_reserved_area);
5329
5330#ifdef  CONFIG_HIGHMEM
5331void free_highmem_page(struct page *page)
5332{
5333        __free_reserved_page(page);
5334        totalram_pages++;
5335        page_zone(page)->managed_pages++;
5336        totalhigh_pages++;
5337}
5338#endif
5339
5340
5341void __init mem_init_print_info(const char *str)
5342{
5343        unsigned long physpages, codesize, datasize, rosize, bss_size;
5344        unsigned long init_code_size, init_data_size;
5345
5346        physpages = get_num_physpages();
5347        codesize = _etext - _stext;
5348        datasize = _edata - _sdata;
5349        rosize = __end_rodata - __start_rodata;
5350        bss_size = __bss_stop - __bss_start;
5351        init_data_size = __init_end - __init_begin;
5352        init_code_size = _einittext - _sinittext;
5353
5354        /*
5355         * Detect special cases and adjust section sizes accordingly:
5356         * 1) .init.* may be embedded into .data sections
5357         * 2) .init.text.* may be out of [__init_begin, __init_end],
5358         *    please refer to arch/tile/kernel/vmlinux.lds.S.
5359         * 3) .rodata.* may be embedded into .text or .data sections.
5360         */
5361#define adj_init_size(start, end, size, pos, adj) \
5362        do { \
5363                if (start <= pos && pos < end && size > adj) \
5364                        size -= adj; \
5365        } while (0)
5366
5367        adj_init_size(__init_begin, __init_end, init_data_size,
5368                     _sinittext, init_code_size);
5369        adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
5370        adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
5371        adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
5372        adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
5373
5374#undef  adj_init_size
5375
5376        printk("Memory: %luK/%luK available "
5377               "(%luK kernel code, %luK rwdata, %luK rodata, "
5378               "%luK init, %luK bss, %luK reserved"
5379#ifdef  CONFIG_HIGHMEM
5380               ", %luK highmem"
5381#endif
5382               "%s%s)\n",
5383               nr_free_pages() << (PAGE_SHIFT-10), physpages << (PAGE_SHIFT-10),
5384               codesize >> 10, datasize >> 10, rosize >> 10,
5385               (init_data_size + init_code_size) >> 10, bss_size >> 10,
5386               (physpages - totalram_pages) << (PAGE_SHIFT-10),
5387#ifdef  CONFIG_HIGHMEM
5388               totalhigh_pages << (PAGE_SHIFT-10),
5389#endif
5390               str ? ", " : "", str ? str : "");
5391}
5392
5393/**
5394 * set_dma_reserve - set the specified number of pages reserved in the first zone
5395 * @new_dma_reserve: The number of pages to mark reserved
5396 *
5397 * The per-cpu batchsize and zone watermarks are determined by present_pages.
5398 * In the DMA zone, a significant percentage may be consumed by kernel image
5399 * and other unfreeable allocations which can skew the watermarks badly. This
5400 * function may optionally be used to account for unfreeable pages in the
5401 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
5402 * smaller per-cpu batchsize.
5403 */
5404void __init set_dma_reserve(unsigned long new_dma_reserve)
5405{
5406        dma_reserve = new_dma_reserve;
5407}
5408
5409void __init free_area_init(unsigned long *zones_size)
5410{
5411        free_area_init_node(0, zones_size,
5412                        __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
5413}
5414
5415static int page_alloc_cpu_notify(struct notifier_block *self,
5416                                 unsigned long action, void *hcpu)
5417{
5418        int cpu = (unsigned long)hcpu;
5419
5420        if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
5421                lru_add_drain_cpu(cpu);
5422                drain_pages(cpu);
5423
5424                /*
5425                 * Spill the event counters of the dead processor
5426                 * into the current processors event counters.
5427                 * This artificially elevates the count of the current
5428                 * processor.
5429                 */
5430                vm_events_fold_cpu(cpu);
5431
5432                /*
5433                 * Zero the differential counters of the dead processor
5434                 * so that the vm statistics are consistent.
5435                 *
5436                 * This is only okay since the processor is dead and cannot
5437                 * race with what we are doing.
5438                 */
5439                cpu_vm_stats_fold(cpu);
5440        }
5441        return NOTIFY_OK;
5442}
5443
5444void __init page_alloc_init(void)
5445{
5446        hotcpu_notifier(page_alloc_cpu_notify, 0);
5447}
5448
5449/*
5450 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
5451 *      or min_free_kbytes changes.
5452 */
5453static void calculate_totalreserve_pages(void)
5454{
5455        struct pglist_data *pgdat;
5456        unsigned long reserve_pages = 0;
5457        enum zone_type i, j;
5458
5459        for_each_online_pgdat(pgdat) {
5460                for (i = 0; i < MAX_NR_ZONES; i++) {
5461                        struct zone *zone = pgdat->node_zones + i;
5462                        unsigned long max = 0;
5463
5464                        /* Find valid and maximum lowmem_reserve in the zone */
5465                        for (j = i; j < MAX_NR_ZONES; j++) {
5466                                if (zone->lowmem_reserve[j] > max)
5467                                        max = zone->lowmem_reserve[j];
5468                        }
5469
5470                        /* we treat the high watermark as reserved pages. */
5471                        max += high_wmark_pages(zone);
5472
5473                        if (max > zone->managed_pages)
5474                                max = zone->managed_pages;
5475                        reserve_pages += max;
5476                        /*
5477                         * Lowmem reserves are not available to
5478                         * GFP_HIGHUSER page cache allocations and
5479                         * kswapd tries to balance zones to their high
5480                         * watermark.  As a result, neither should be
5481                         * regarded as dirtyable memory, to prevent a
5482                         * situation where reclaim has to clean pages
5483                         * in order to balance the zones.
5484                         */
5485                        zone->dirty_balance_reserve = max;
5486                }
5487        }
5488        dirty_balance_reserve = reserve_pages;
5489        totalreserve_pages = reserve_pages;
5490}
5491
5492/*
5493 * setup_per_zone_lowmem_reserve - called whenever
5494 *      sysctl_lower_zone_reserve_ratio changes.  Ensures that each zone
5495 *      has a correct pages reserved value, so an adequate number of
5496 *      pages are left in the zone after a successful __alloc_pages().
5497 */
5498static void setup_per_zone_lowmem_reserve(void)
5499{
5500        struct pglist_data *pgdat;
5501        enum zone_type j, idx;
5502
5503        for_each_online_pgdat(pgdat) {
5504                for (j = 0; j < MAX_NR_ZONES; j++) {
5505                        struct zone *zone = pgdat->node_zones + j;
5506                        unsigned long managed_pages = zone->managed_pages;
5507
5508                        zone->lowmem_reserve[j] = 0;
5509
5510                        idx = j;
5511                        while (idx) {
5512                                struct zone *lower_zone;
5513
5514                                idx--;
5515
5516                                if (sysctl_lowmem_reserve_ratio[idx] < 1)
5517                                        sysctl_lowmem_reserve_ratio[idx] = 1;
5518
5519                                lower_zone = pgdat->node_zones + idx;
5520                                lower_zone->lowmem_reserve[j] = managed_pages /
5521                                        sysctl_lowmem_reserve_ratio[idx];
5522                                managed_pages += lower_zone->managed_pages;
5523                        }
5524                }
5525        }
5526
5527        /* update totalreserve_pages */
5528        calculate_totalreserve_pages();
5529}
5530
5531static void __setup_per_zone_wmarks(void)
5532{
5533        unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
5534        unsigned long lowmem_pages = 0;
5535        struct zone *zone;
5536        unsigned long flags;
5537
5538        /* Calculate total number of !ZONE_HIGHMEM pages */
5539        for_each_zone(zone) {
5540                if (!is_highmem(zone))
5541                        lowmem_pages += zone->managed_pages;
5542        }
5543
5544        for_each_zone(zone) {
5545                u64 tmp;
5546
5547                spin_lock_irqsave(&zone->lock, flags);
5548                tmp = (u64)pages_min * zone->managed_pages;
5549                do_div(tmp, lowmem_pages);
5550                if (is_highmem(zone)) {
5551                        /*
5552                         * __GFP_HIGH and PF_MEMALLOC allocations usually don't
5553                         * need highmem pages, so cap pages_min to a small
5554                         * value here.
5555                         *
5556                         * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
5557                         * deltas controls asynch page reclaim, and so should
5558                         * not be capped for highmem.
5559                         */
5560                        unsigned long min_pages;
5561
5562                        min_pages = zone->managed_pages / 1024;
5563                        min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
5564                        zone->watermark[WMARK_MIN] = min_pages;
5565                } else {
5566                        /*
5567                         * If it's a lowmem zone, reserve a number of pages
5568                         * proportionate to the zone's size.
5569                         */
5570                        zone->watermark[WMARK_MIN] = tmp;
5571                }
5572
5573                zone->watermark[WMARK_LOW]  = min_wmark_pages(zone) + (tmp >> 2);
5574                zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
5575
5576                __mod_zone_page_state(zone, NR_ALLOC_BATCH,
5577                                      high_wmark_pages(zone) -
5578                                      low_wmark_pages(zone) -
5579                                      zone_page_state(zone, NR_ALLOC_BATCH));
5580
5581                setup_zone_migrate_reserve(zone);
5582                spin_unlock_irqrestore(&zone->lock, flags);
5583        }
5584
5585        /* update totalreserve_pages */
5586        calculate_totalreserve_pages();
5587}
5588
5589/**
5590 * setup_per_zone_wmarks - called when min_free_kbytes changes
5591 * or when memory is hot-{added|removed}
5592 *
5593 * Ensures that the watermark[min,low,high] values for each zone are set
5594 * correctly with respect to min_free_kbytes.
5595 */
5596void setup_per_zone_wmarks(void)
5597{
5598        mutex_lock(&zonelists_mutex);
5599        __setup_per_zone_wmarks();
5600        mutex_unlock(&zonelists_mutex);
5601}
5602
5603/*
5604 * The inactive anon list should be small enough that the VM never has to
5605 * do too much work, but large enough that each inactive page has a chance
5606 * to be referenced again before it is swapped out.
5607 *
5608 * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
5609 * INACTIVE_ANON pages on this zone's LRU, maintained by the
5610 * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
5611 * the anonymous pages are kept on the inactive list.
5612 *
5613 * total     target    max
5614 * memory    ratio     inactive anon
5615 * -------------------------------------
5616 *   10MB       1         5MB
5617 *  100MB       1        50MB
5618 *    1GB       3       250MB
5619 *   10GB      10       0.9GB
5620 *  100GB      31         3GB
5621 *    1TB     101        10GB
5622 *   10TB     320        32GB
5623 */
5624static void __meminit calculate_zone_inactive_ratio(struct zone *zone)
5625{
5626        unsigned int gb, ratio;
5627
5628        /* Zone size in gigabytes */
5629        gb = zone->managed_pages >> (30 - PAGE_SHIFT);
5630        if (gb)
5631                ratio = int_sqrt(10 * gb);
5632        else
5633                ratio = 1;
5634
5635        zone->inactive_ratio = ratio;
5636}
5637
5638static void __meminit setup_per_zone_inactive_ratio(void)
5639{
5640        struct zone *zone;
5641
5642        for_each_zone(zone)
5643                calculate_zone_inactive_ratio(zone);
5644}
5645
5646/*
5647 * Initialise min_free_kbytes.
5648 *
5649 * For small machines we want it small (128k min).  For large machines
5650 * we want it large (64MB max).  But it is not linear, because network
5651 * bandwidth does not increase linearly with machine size.  We use
5652 *
5653 *      min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
5654 *      min_free_kbytes = sqrt(lowmem_kbytes * 16)
5655 *
5656 * which yields
5657 *
5658 * 16MB:        512k
5659 * 32MB:        724k
5660 * 64MB:        1024k
5661 * 128MB:       1448k
5662 * 256MB:       2048k
5663 * 512MB:       2896k
5664 * 1024MB:      4096k
5665 * 2048MB:      5792k
5666 * 4096MB:      8192k
5667 * 8192MB:      11584k
5668 * 16384MB:     16384k
5669 */
5670int __meminit init_per_zone_wmark_min(void)
5671{
5672        unsigned long lowmem_kbytes;
5673        int new_min_free_kbytes;
5674
5675        lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
5676        new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
5677
5678        if (new_min_free_kbytes > user_min_free_kbytes) {
5679                min_free_kbytes = new_min_free_kbytes;
5680                if (min_free_kbytes < 128)
5681                        min_free_kbytes = 128;
5682                if (min_free_kbytes > 65536)
5683                        min_free_kbytes = 65536;
5684        } else {
5685                pr_warn("min_free_kbytes is not updated to %d because user defined value