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/compiler.h>
  25#include <linux/kernel.h>
  26#include <linux/module.h>
  27#include <linux/suspend.h>
  28#include <linux/pagevec.h>
  29#include <linux/blkdev.h>
  30#include <linux/slab.h>
  31#include <linux/oom.h>
  32#include <linux/notifier.h>
  33#include <linux/topology.h>
  34#include <linux/sysctl.h>
  35#include <linux/cpu.h>
  36#include <linux/cpuset.h>
  37#include <linux/memory_hotplug.h>
  38#include <linux/nodemask.h>
  39#include <linux/vmalloc.h>
  40#include <linux/mempolicy.h>
  41#include <linux/stop_machine.h>
  42#include <linux/sort.h>
  43#include <linux/pfn.h>
  44#include <linux/backing-dev.h>
  45#include <linux/fault-inject.h>
  46#include <linux/page-isolation.h>
  47#include <linux/page_cgroup.h>
  48#include <linux/debugobjects.h>
  49
  50#include <asm/tlbflush.h>
  51#include <asm/div64.h>
  52#include "internal.h"
  53
  54/*
  55 * Array of node states.
  56 */
  57nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
  58        [N_POSSIBLE] = NODE_MASK_ALL,
  59        [N_ONLINE] = { { [0] = 1UL } },
  60#ifndef CONFIG_NUMA
  61        [N_NORMAL_MEMORY] = { { [0] = 1UL } },
  62#ifdef CONFIG_HIGHMEM
  63        [N_HIGH_MEMORY] = { { [0] = 1UL } },
  64#endif
  65        [N_CPU] = { { [0] = 1UL } },
  66#endif  /* NUMA */
  67};
  68EXPORT_SYMBOL(node_states);
  69
  70unsigned long totalram_pages __read_mostly;
  71unsigned long totalreserve_pages __read_mostly;
  72long nr_swap_pages;
  73int percpu_pagelist_fraction;
  74
  75#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
  76int pageblock_order __read_mostly;
  77#endif
  78
  79static void __free_pages_ok(struct page *page, unsigned int order);
  80
  81/*
  82 * results with 256, 32 in the lowmem_reserve sysctl:
  83 *      1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
  84 *      1G machine -> (16M dma, 784M normal, 224M high)
  85 *      NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
  86 *      HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
  87 *      HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
  88 *
  89 * TBD: should special case ZONE_DMA32 machines here - in those we normally
  90 * don't need any ZONE_NORMAL reservation
  91 */
  92int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
  93#ifdef CONFIG_ZONE_DMA
  94         256,
  95#endif
  96#ifdef CONFIG_ZONE_DMA32
  97         256,
  98#endif
  99#ifdef CONFIG_HIGHMEM
 100         32,
 101#endif
 102         32,
 103};
 104
 105EXPORT_SYMBOL(totalram_pages);
 106
 107static char * const zone_names[MAX_NR_ZONES] = {
 108#ifdef CONFIG_ZONE_DMA
 109         "DMA",
 110#endif
 111#ifdef CONFIG_ZONE_DMA32
 112         "DMA32",
 113#endif
 114         "Normal",
 115#ifdef CONFIG_HIGHMEM
 116         "HighMem",
 117#endif
 118         "Movable",
 119};
 120
 121int min_free_kbytes = 1024;
 122
 123unsigned long __meminitdata nr_kernel_pages;
 124unsigned long __meminitdata nr_all_pages;
 125static unsigned long __meminitdata dma_reserve;
 126
 127#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
 128  /*
 129   * MAX_ACTIVE_REGIONS determines the maximum number of distinct
 130   * ranges of memory (RAM) that may be registered with add_active_range().
 131   * Ranges passed to add_active_range() will be merged if possible
 132   * so the number of times add_active_range() can be called is
 133   * related to the number of nodes and the number of holes
 134   */
 135  #ifdef CONFIG_MAX_ACTIVE_REGIONS
 136    /* Allow an architecture to set MAX_ACTIVE_REGIONS to save memory */
 137    #define MAX_ACTIVE_REGIONS CONFIG_MAX_ACTIVE_REGIONS
 138  #else
 139    #if MAX_NUMNODES >= 32
 140      /* If there can be many nodes, allow up to 50 holes per node */
 141      #define MAX_ACTIVE_REGIONS (MAX_NUMNODES*50)
 142    #else
 143      /* By default, allow up to 256 distinct regions */
 144      #define MAX_ACTIVE_REGIONS 256
 145    #endif
 146  #endif
 147
 148  static struct node_active_region __meminitdata early_node_map[MAX_ACTIVE_REGIONS];
 149  static int __meminitdata nr_nodemap_entries;
 150  static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
 151  static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
 152#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
 153  static unsigned long __meminitdata node_boundary_start_pfn[MAX_NUMNODES];
 154  static unsigned long __meminitdata node_boundary_end_pfn[MAX_NUMNODES];
 155#endif /* CONFIG_MEMORY_HOTPLUG_RESERVE */
 156  static unsigned long __initdata required_kernelcore;
 157  static unsigned long __initdata required_movablecore;
 158  static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
 159
 160  /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
 161  int movable_zone;
 162  EXPORT_SYMBOL(movable_zone);
 163#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
 164
 165#if MAX_NUMNODES > 1
 166int nr_node_ids __read_mostly = MAX_NUMNODES;
 167EXPORT_SYMBOL(nr_node_ids);
 168#endif
 169
 170int page_group_by_mobility_disabled __read_mostly;
 171
 172static void set_pageblock_migratetype(struct page *page, int migratetype)
 173{
 174        set_pageblock_flags_group(page, (unsigned long)migratetype,
 175                                        PB_migrate, PB_migrate_end);
 176}
 177
 178#ifdef CONFIG_DEBUG_VM
 179static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
 180{
 181        int ret = 0;
 182        unsigned seq;
 183        unsigned long pfn = page_to_pfn(page);
 184
 185        do {
 186                seq = zone_span_seqbegin(zone);
 187                if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
 188                        ret = 1;
 189                else if (pfn < zone->zone_start_pfn)
 190                        ret = 1;
 191        } while (zone_span_seqretry(zone, seq));
 192
 193        return ret;
 194}
 195
 196static int page_is_consistent(struct zone *zone, struct page *page)
 197{
 198        if (!pfn_valid_within(page_to_pfn(page)))
 199                return 0;
 200        if (zone != page_zone(page))
 201                return 0;
 202
 203        return 1;
 204}
 205/*
 206 * Temporary debugging check for pages not lying within a given zone.
 207 */
 208static int bad_range(struct zone *zone, struct page *page)
 209{
 210        if (page_outside_zone_boundaries(zone, page))
 211                return 1;
 212        if (!page_is_consistent(zone, page))
 213                return 1;
 214
 215        return 0;
 216}
 217#else
 218static inline int bad_range(struct zone *zone, struct page *page)
 219{
 220        return 0;
 221}
 222#endif
 223
 224static void bad_page(struct page *page)
 225{
 226        printk(KERN_EMERG "Bad page state in process '%s'\n" KERN_EMERG
 227                "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n",
 228                current->comm, page, (int)(2*sizeof(unsigned long)),
 229                (unsigned long)page->flags, page->mapping,
 230                page_mapcount(page), page_count(page));
 231
 232        printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
 233                KERN_EMERG "Backtrace:\n");
 234        dump_stack();
 235        page->flags &= ~PAGE_FLAGS_CLEAR_WHEN_BAD;
 236        set_page_count(page, 0);
 237        reset_page_mapcount(page);
 238        page->mapping = NULL;
 239        add_taint(TAINT_BAD_PAGE);
 240}
 241
 242/*
 243 * Higher-order pages are called "compound pages".  They are structured thusly:
 244 *
 245 * The first PAGE_SIZE page is called the "head page".
 246 *
 247 * The remaining PAGE_SIZE pages are called "tail pages".
 248 *
 249 * All pages have PG_compound set.  All pages have their ->private pointing at
 250 * the head page (even the head page has this).
 251 *
 252 * The first tail page's ->lru.next holds the address of the compound page's
 253 * put_page() function.  Its ->lru.prev holds the order of allocation.
 254 * This usage means that zero-order pages may not be compound.
 255 */
 256
 257static void free_compound_page(struct page *page)
 258{
 259        __free_pages_ok(page, compound_order(page));
 260}
 261
 262void prep_compound_page(struct page *page, unsigned long order)
 263{
 264        int i;
 265        int nr_pages = 1 << order;
 266
 267        set_compound_page_dtor(page, free_compound_page);
 268        set_compound_order(page, order);
 269        __SetPageHead(page);
 270        for (i = 1; i < nr_pages; i++) {
 271                struct page *p = page + i;
 272
 273                __SetPageTail(p);
 274                p->first_page = page;
 275        }
 276}
 277
 278#ifdef CONFIG_HUGETLBFS
 279void prep_compound_gigantic_page(struct page *page, unsigned long order)
 280{
 281        int i;
 282        int nr_pages = 1 << order;
 283        struct page *p = page + 1;
 284
 285        set_compound_page_dtor(page, free_compound_page);
 286        set_compound_order(page, order);
 287        __SetPageHead(page);
 288        for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
 289                __SetPageTail(p);
 290                p->first_page = page;
 291        }
 292}
 293#endif
 294
 295static void destroy_compound_page(struct page *page, unsigned long order)
 296{
 297        int i;
 298        int nr_pages = 1 << order;
 299
 300        if (unlikely(compound_order(page) != order))
 301                bad_page(page);
 302
 303        if (unlikely(!PageHead(page)))
 304                        bad_page(page);
 305        __ClearPageHead(page);
 306        for (i = 1; i < nr_pages; i++) {
 307                struct page *p = page + i;
 308
 309                if (unlikely(!PageTail(p) |
 310                                (p->first_page != page)))
 311                        bad_page(page);
 312                __ClearPageTail(p);
 313        }
 314}
 315
 316static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
 317{
 318        int i;
 319
 320        /*
 321         * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
 322         * and __GFP_HIGHMEM from hard or soft interrupt context.
 323         */
 324        VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
 325        for (i = 0; i < (1 << order); i++)
 326                clear_highpage(page + i);
 327}
 328
 329static inline void set_page_order(struct page *page, int order)
 330{
 331        set_page_private(page, order);
 332        __SetPageBuddy(page);
 333}
 334
 335static inline void rmv_page_order(struct page *page)
 336{
 337        __ClearPageBuddy(page);
 338        set_page_private(page, 0);
 339}
 340
 341/*
 342 * Locate the struct page for both the matching buddy in our
 343 * pair (buddy1) and the combined O(n+1) page they form (page).
 344 *
 345 * 1) Any buddy B1 will have an order O twin B2 which satisfies
 346 * the following equation:
 347 *     B2 = B1 ^ (1 << O)
 348 * For example, if the starting buddy (buddy2) is #8 its order
 349 * 1 buddy is #10:
 350 *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
 351 *
 352 * 2) Any buddy B will have an order O+1 parent P which
 353 * satisfies the following equation:
 354 *     P = B & ~(1 << O)
 355 *
 356 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
 357 */
 358static inline struct page *
 359__page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
 360{
 361        unsigned long buddy_idx = page_idx ^ (1 << order);
 362
 363        return page + (buddy_idx - page_idx);
 364}
 365
 366static inline unsigned long
 367__find_combined_index(unsigned long page_idx, unsigned int order)
 368{
 369        return (page_idx & ~(1 << order));
 370}
 371
 372/*
 373 * This function checks whether a page is free && is the buddy
 374 * we can do coalesce a page and its buddy if
 375 * (a) the buddy is not in a hole &&
 376 * (b) the buddy is in the buddy system &&
 377 * (c) a page and its buddy have the same order &&
 378 * (d) a page and its buddy are in the same zone.
 379 *
 380 * For recording whether a page is in the buddy system, we use PG_buddy.
 381 * Setting, clearing, and testing PG_buddy is serialized by zone->lock.
 382 *
 383 * For recording page's order, we use page_private(page).
 384 */
 385static inline int page_is_buddy(struct page *page, struct page *buddy,
 386                                                                int order)
 387{
 388        if (!pfn_valid_within(page_to_pfn(buddy)))
 389                return 0;
 390
 391        if (page_zone_id(page) != page_zone_id(buddy))
 392                return 0;
 393
 394        if (PageBuddy(buddy) && page_order(buddy) == order) {
 395                BUG_ON(page_count(buddy) != 0);
 396                return 1;
 397        }
 398        return 0;
 399}
 400
 401/*
 402 * Freeing function for a buddy system allocator.
 403 *
 404 * The concept of a buddy system is to maintain direct-mapped table
 405 * (containing bit values) for memory blocks of various "orders".
 406 * The bottom level table contains the map for the smallest allocatable
 407 * units of memory (here, pages), and each level above it describes
 408 * pairs of units from the levels below, hence, "buddies".
 409 * At a high level, all that happens here is marking the table entry
 410 * at the bottom level available, and propagating the changes upward
 411 * as necessary, plus some accounting needed to play nicely with other
 412 * parts of the VM system.
 413 * At each level, we keep a list of pages, which are heads of continuous
 414 * free pages of length of (1 << order) and marked with PG_buddy. Page's
 415 * order is recorded in page_private(page) field.
 416 * So when we are allocating or freeing one, we can derive the state of the
 417 * other.  That is, if we allocate a small block, and both were   
 418 * free, the remainder of the region must be split into blocks.   
 419 * If a block is freed, and its buddy is also free, then this
 420 * triggers coalescing into a block of larger size.            
 421 *
 422 * -- wli
 423 */
 424
 425static inline void __free_one_page(struct page *page,
 426                struct zone *zone, unsigned int order)
 427{
 428        unsigned long page_idx;
 429        int order_size = 1 << order;
 430        int migratetype = get_pageblock_migratetype(page);
 431
 432        if (unlikely(PageCompound(page)))
 433                destroy_compound_page(page, order);
 434
 435        page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
 436
 437        VM_BUG_ON(page_idx & (order_size - 1));
 438        VM_BUG_ON(bad_range(zone, page));
 439
 440        __mod_zone_page_state(zone, NR_FREE_PAGES, order_size);
 441        while (order < MAX_ORDER-1) {
 442                unsigned long combined_idx;
 443                struct page *buddy;
 444
 445                buddy = __page_find_buddy(page, page_idx, order);
 446                if (!page_is_buddy(page, buddy, order))
 447                        break;
 448
 449                /* Our buddy is free, merge with it and move up one order. */
 450                list_del(&buddy->lru);
 451                zone->free_area[order].nr_free--;
 452                rmv_page_order(buddy);
 453                combined_idx = __find_combined_index(page_idx, order);
 454                page = page + (combined_idx - page_idx);
 455                page_idx = combined_idx;
 456                order++;
 457        }
 458        set_page_order(page, order);
 459        list_add(&page->lru,
 460                &zone->free_area[order].free_list[migratetype]);
 461        zone->free_area[order].nr_free++;
 462}
 463
 464static inline int free_pages_check(struct page *page)
 465{
 466        free_page_mlock(page);
 467        if (unlikely(page_mapcount(page) |
 468                (page->mapping != NULL)  |
 469                (page_count(page) != 0)  |
 470                (page->flags & PAGE_FLAGS_CHECK_AT_FREE)))
 471                bad_page(page);
 472        if (PageDirty(page))
 473                __ClearPageDirty(page);
 474        if (PageSwapBacked(page))
 475                __ClearPageSwapBacked(page);
 476        /*
 477         * For now, we report if PG_reserved was found set, but do not
 478         * clear it, and do not free the page.  But we shall soon need
 479         * to do more, for when the ZERO_PAGE count wraps negative.
 480         */
 481        return PageReserved(page);
 482}
 483
 484/*
 485 * Frees a list of pages. 
 486 * Assumes all pages on list are in same zone, and of same order.
 487 * count is the number of pages to free.
 488 *
 489 * If the zone was previously in an "all pages pinned" state then look to
 490 * see if this freeing clears that state.
 491 *
 492 * And clear the zone's pages_scanned counter, to hold off the "all pages are
 493 * pinned" detection logic.
 494 */
 495static void free_pages_bulk(struct zone *zone, int count,
 496                                        struct list_head *list, int order)
 497{
 498        spin_lock(&zone->lock);
 499        zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
 500        zone->pages_scanned = 0;
 501        while (count--) {
 502                struct page *page;
 503
 504                VM_BUG_ON(list_empty(list));
 505                page = list_entry(list->prev, struct page, lru);
 506                /* have to delete it as __free_one_page list manipulates */
 507                list_del(&page->lru);
 508                __free_one_page(page, zone, order);
 509        }
 510        spin_unlock(&zone->lock);
 511}
 512
 513static void free_one_page(struct zone *zone, struct page *page, int order)
 514{
 515        spin_lock(&zone->lock);
 516        zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
 517        zone->pages_scanned = 0;
 518        __free_one_page(page, zone, order);
 519        spin_unlock(&zone->lock);
 520}
 521
 522static void __free_pages_ok(struct page *page, unsigned int order)
 523{
 524        unsigned long flags;
 525        int i;
 526        int reserved = 0;
 527
 528        for (i = 0 ; i < (1 << order) ; ++i)
 529                reserved += free_pages_check(page + i);
 530        if (reserved)
 531                return;
 532
 533        if (!PageHighMem(page)) {
 534                debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
 535                debug_check_no_obj_freed(page_address(page),
 536                                           PAGE_SIZE << order);
 537        }
 538        arch_free_page(page, order);
 539        kernel_map_pages(page, 1 << order, 0);
 540
 541        local_irq_save(flags);
 542        __count_vm_events(PGFREE, 1 << order);
 543        free_one_page(page_zone(page), page, order);
 544        local_irq_restore(flags);
 545}
 546
 547/*
 548 * permit the bootmem allocator to evade page validation on high-order frees
 549 */
 550void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
 551{
 552        if (order == 0) {
 553                __ClearPageReserved(page);
 554                set_page_count(page, 0);
 555                set_page_refcounted(page);
 556                __free_page(page);
 557        } else {
 558                int loop;
 559
 560                prefetchw(page);
 561                for (loop = 0; loop < BITS_PER_LONG; loop++) {
 562                        struct page *p = &page[loop];
 563
 564                        if (loop + 1 < BITS_PER_LONG)
 565                                prefetchw(p + 1);
 566                        __ClearPageReserved(p);
 567                        set_page_count(p, 0);
 568                }
 569
 570                set_page_refcounted(page);
 571                __free_pages(page, order);
 572        }
 573}
 574
 575
 576/*
 577 * The order of subdivision here is critical for the IO subsystem.
 578 * Please do not alter this order without good reasons and regression
 579 * testing. Specifically, as large blocks of memory are subdivided,
 580 * the order in which smaller blocks are delivered depends on the order
 581 * they're subdivided in this function. This is the primary factor
 582 * influencing the order in which pages are delivered to the IO
 583 * subsystem according to empirical testing, and this is also justified
 584 * by considering the behavior of a buddy system containing a single
 585 * large block of memory acted on by a series of small allocations.
 586 * This behavior is a critical factor in sglist merging's success.
 587 *
 588 * -- wli
 589 */
 590static inline void expand(struct zone *zone, struct page *page,
 591        int low, int high, struct free_area *area,
 592        int migratetype)
 593{
 594        unsigned long size = 1 << high;
 595
 596        while (high > low) {
 597                area--;
 598                high--;
 599                size >>= 1;
 600                VM_BUG_ON(bad_range(zone, &page[size]));
 601                list_add(&page[size].lru, &area->free_list[migratetype]);
 602                area->nr_free++;
 603                set_page_order(&page[size], high);
 604        }
 605}
 606
 607/*
 608 * This page is about to be returned from the page allocator
 609 */
 610static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
 611{
 612        if (unlikely(page_mapcount(page) |
 613                (page->mapping != NULL)  |
 614                (page_count(page) != 0)  |
 615                (page->flags & PAGE_FLAGS_CHECK_AT_PREP)))
 616                bad_page(page);
 617
 618        /*
 619         * For now, we report if PG_reserved was found set, but do not
 620         * clear it, and do not allocate the page: as a safety net.
 621         */
 622        if (PageReserved(page))
 623                return 1;
 624
 625        page->flags &= ~(1 << PG_uptodate | 1 << PG_error | 1 << PG_reclaim |
 626                        1 << PG_referenced | 1 << PG_arch_1 |
 627                        1 << PG_owner_priv_1 | 1 << PG_mappedtodisk
 628#ifdef CONFIG_UNEVICTABLE_LRU
 629                        | 1 << PG_mlocked
 630#endif
 631                        );
 632        set_page_private(page, 0);
 633        set_page_refcounted(page);
 634
 635        arch_alloc_page(page, order);
 636        kernel_map_pages(page, 1 << order, 1);
 637
 638        if (gfp_flags & __GFP_ZERO)
 639                prep_zero_page(page, order, gfp_flags);
 640
 641        if (order && (gfp_flags & __GFP_COMP))
 642                prep_compound_page(page, order);
 643
 644        return 0;
 645}
 646
 647/*
 648 * Go through the free lists for the given migratetype and remove
 649 * the smallest available page from the freelists
 650 */
 651static struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
 652                                                int migratetype)
 653{
 654        unsigned int current_order;
 655        struct free_area * area;
 656        struct page *page;
 657
 658        /* Find a page of the appropriate size in the preferred list */
 659        for (current_order = order; current_order < MAX_ORDER; ++current_order) {
 660                area = &(zone->free_area[current_order]);
 661                if (list_empty(&area->free_list[migratetype]))
 662                        continue;
 663
 664                page = list_entry(area->free_list[migratetype].next,
 665                                                        struct page, lru);
 666                list_del(&page->lru);
 667                rmv_page_order(page);
 668                area->nr_free--;
 669                __mod_zone_page_state(zone, NR_FREE_PAGES, - (1UL << order));
 670                expand(zone, page, order, current_order, area, migratetype);
 671                return page;
 672        }
 673
 674        return NULL;
 675}
 676
 677
 678/*
 679 * This array describes the order lists are fallen back to when
 680 * the free lists for the desirable migrate type are depleted
 681 */
 682static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = {
 683        [MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_RESERVE },
 684        [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_RESERVE },
 685        [MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
 686        [MIGRATE_RESERVE]     = { MIGRATE_RESERVE,     MIGRATE_RESERVE,   MIGRATE_RESERVE }, /* Never used */
 687};
 688
 689/*
 690 * Move the free pages in a range to the free lists of the requested type.
 691 * Note that start_page and end_pages are not aligned on a pageblock
 692 * boundary. If alignment is required, use move_freepages_block()
 693 */
 694static int move_freepages(struct zone *zone,
 695                          struct page *start_page, struct page *end_page,
 696                          int migratetype)
 697{
 698        struct page *page;
 699        unsigned long order;
 700        int pages_moved = 0;
 701
 702#ifndef CONFIG_HOLES_IN_ZONE
 703        /*
 704         * page_zone is not safe to call in this context when
 705         * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
 706         * anyway as we check zone boundaries in move_freepages_block().
 707         * Remove at a later date when no bug reports exist related to
 708         * grouping pages by mobility
 709         */
 710        BUG_ON(page_zone(start_page) != page_zone(end_page));
 711#endif
 712
 713        for (page = start_page; page <= end_page;) {
 714                /* Make sure we are not inadvertently changing nodes */
 715                VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
 716
 717                if (!pfn_valid_within(page_to_pfn(page))) {
 718                        page++;
 719                        continue;
 720                }
 721
 722                if (!PageBuddy(page)) {
 723                        page++;
 724                        continue;
 725                }
 726
 727                order = page_order(page);
 728                list_del(&page->lru);
 729                list_add(&page->lru,
 730                        &zone->free_area[order].free_list[migratetype]);
 731                page += 1 << order;
 732                pages_moved += 1 << order;
 733        }
 734
 735        return pages_moved;
 736}
 737
 738static int move_freepages_block(struct zone *zone, struct page *page,
 739                                int migratetype)
 740{
 741        unsigned long start_pfn, end_pfn;
 742        struct page *start_page, *end_page;
 743
 744        start_pfn = page_to_pfn(page);
 745        start_pfn = start_pfn & ~(pageblock_nr_pages-1);
 746        start_page = pfn_to_page(start_pfn);
 747        end_page = start_page + pageblock_nr_pages - 1;
 748        end_pfn = start_pfn + pageblock_nr_pages - 1;
 749
 750        /* Do not cross zone boundaries */
 751        if (start_pfn < zone->zone_start_pfn)
 752                start_page = page;
 753        if (end_pfn >= zone->zone_start_pfn + zone->spanned_pages)
 754                return 0;
 755
 756        return move_freepages(zone, start_page, end_page, migratetype);
 757}
 758
 759/* Remove an element from the buddy allocator from the fallback list */
 760static struct page *__rmqueue_fallback(struct zone *zone, int order,
 761                                                int start_migratetype)
 762{
 763        struct free_area * area;
 764        int current_order;
 765        struct page *page;
 766        int migratetype, i;
 767
 768        /* Find the largest possible block of pages in the other list */
 769        for (current_order = MAX_ORDER-1; current_order >= order;
 770                                                --current_order) {
 771                for (i = 0; i < MIGRATE_TYPES - 1; i++) {
 772                        migratetype = fallbacks[start_migratetype][i];
 773
 774                        /* MIGRATE_RESERVE handled later if necessary */
 775                        if (migratetype == MIGRATE_RESERVE)
 776                                continue;
 777
 778                        area = &(zone->free_area[current_order]);
 779                        if (list_empty(&area->free_list[migratetype]))
 780                                continue;
 781
 782                        page = list_entry(area->free_list[migratetype].next,
 783                                        struct page, lru);
 784                        area->nr_free--;
 785
 786                        /*
 787                         * If breaking a large block of pages, move all free
 788                         * pages to the preferred allocation list. If falling
 789                         * back for a reclaimable kernel allocation, be more
 790                         * agressive about taking ownership of free pages
 791                         */
 792                        if (unlikely(current_order >= (pageblock_order >> 1)) ||
 793                                        start_migratetype == MIGRATE_RECLAIMABLE) {
 794                                unsigned long pages;
 795                                pages = move_freepages_block(zone, page,
 796                                                                start_migratetype);
 797
 798                                /* Claim the whole block if over half of it is free */
 799                                if (pages >= (1 << (pageblock_order-1)))
 800                                        set_pageblock_migratetype(page,
 801                                                                start_migratetype);
 802
 803                                migratetype = start_migratetype;
 804                        }
 805
 806                        /* Remove the page from the freelists */
 807                        list_del(&page->lru);
 808                        rmv_page_order(page);
 809                        __mod_zone_page_state(zone, NR_FREE_PAGES,
 810                                                        -(1UL << order));
 811
 812                        if (current_order == pageblock_order)
 813                                set_pageblock_migratetype(page,
 814                                                        start_migratetype);
 815
 816                        expand(zone, page, order, current_order, area, migratetype);
 817                        return page;
 818                }
 819        }
 820
 821        /* Use MIGRATE_RESERVE rather than fail an allocation */
 822        return __rmqueue_smallest(zone, order, MIGRATE_RESERVE);
 823}
 824
 825/*
 826 * Do the hard work of removing an element from the buddy allocator.
 827 * Call me with the zone->lock already held.
 828 */
 829static struct page *__rmqueue(struct zone *zone, unsigned int order,
 830                                                int migratetype)
 831{
 832        struct page *page;
 833
 834        page = __rmqueue_smallest(zone, order, migratetype);
 835
 836        if (unlikely(!page))
 837                page = __rmqueue_fallback(zone, order, migratetype);
 838
 839        return page;
 840}
 841
 842/* 
 843 * Obtain a specified number of elements from the buddy allocator, all under
 844 * a single hold of the lock, for efficiency.  Add them to the supplied list.
 845 * Returns the number of new pages which were placed at *list.
 846 */
 847static int rmqueue_bulk(struct zone *zone, unsigned int order, 
 848                        unsigned long count, struct list_head *list,
 849                        int migratetype)
 850{
 851        int i;
 852        
 853        spin_lock(&zone->lock);
 854        for (i = 0; i < count; ++i) {
 855                struct page *page = __rmqueue(zone, order, migratetype);
 856                if (unlikely(page == NULL))
 857                        break;
 858
 859                /*
 860                 * Split buddy pages returned by expand() are received here
 861                 * in physical page order. The page is added to the callers and
 862                 * list and the list head then moves forward. From the callers
 863                 * perspective, the linked list is ordered by page number in
 864                 * some conditions. This is useful for IO devices that can
 865                 * merge IO requests if the physical pages are ordered
 866                 * properly.
 867                 */
 868                list_add(&page->lru, list);
 869                set_page_private(page, migratetype);
 870                list = &page->lru;
 871        }
 872        spin_unlock(&zone->lock);
 873        return i;
 874}
 875
 876#ifdef CONFIG_NUMA
 877/*
 878 * Called from the vmstat counter updater to drain pagesets of this
 879 * currently executing processor on remote nodes after they have
 880 * expired.
 881 *
 882 * Note that this function must be called with the thread pinned to
 883 * a single processor.
 884 */
 885void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
 886{
 887        unsigned long flags;
 888        int to_drain;
 889
 890        local_irq_save(flags);
 891        if (pcp->count >= pcp->batch)
 892                to_drain = pcp->batch;
 893        else
 894                to_drain = pcp->count;
 895        free_pages_bulk(zone, to_drain, &pcp->list, 0);
 896        pcp->count -= to_drain;
 897        local_irq_restore(flags);
 898}
 899#endif
 900
 901/*
 902 * Drain pages of the indicated processor.
 903 *
 904 * The processor must either be the current processor and the
 905 * thread pinned to the current processor or a processor that
 906 * is not online.
 907 */
 908static void drain_pages(unsigned int cpu)
 909{
 910        unsigned long flags;
 911        struct zone *zone;
 912
 913        for_each_zone(zone) {
 914                struct per_cpu_pageset *pset;
 915                struct per_cpu_pages *pcp;
 916
 917                if (!populated_zone(zone))
 918                        continue;
 919
 920                pset = zone_pcp(zone, cpu);
 921
 922                pcp = &pset->pcp;
 923                local_irq_save(flags);
 924                free_pages_bulk(zone, pcp->count, &pcp->list, 0);
 925                pcp->count = 0;
 926                local_irq_restore(flags);
 927        }
 928}
 929
 930/*
 931 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
 932 */
 933void drain_local_pages(void *arg)
 934{
 935        drain_pages(smp_processor_id());
 936}
 937
 938/*
 939 * Spill all the per-cpu pages from all CPUs back into the buddy allocator
 940 */
 941void drain_all_pages(void)
 942{
 943        on_each_cpu(drain_local_pages, NULL, 1);
 944}
 945
 946#ifdef CONFIG_HIBERNATION
 947
 948void mark_free_pages(struct zone *zone)
 949{
 950        unsigned long pfn, max_zone_pfn;
 951        unsigned long flags;
 952        int order, t;
 953        struct list_head *curr;
 954
 955        if (!zone->spanned_pages)
 956                return;
 957
 958        spin_lock_irqsave(&zone->lock, flags);
 959
 960        max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
 961        for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
 962                if (pfn_valid(pfn)) {
 963                        struct page *page = pfn_to_page(pfn);
 964
 965                        if (!swsusp_page_is_forbidden(page))
 966                                swsusp_unset_page_free(page);
 967                }
 968
 969        for_each_migratetype_order(order, t) {
 970                list_for_each(curr, &zone->free_area[order].free_list[t]) {
 971                        unsigned long i;
 972
 973                        pfn = page_to_pfn(list_entry(curr, struct page, lru));
 974                        for (i = 0; i < (1UL << order); i++)
 975                                swsusp_set_page_free(pfn_to_page(pfn + i));
 976                }
 977        }
 978        spin_unlock_irqrestore(&zone->lock, flags);
 979}
 980#endif /* CONFIG_PM */
 981
 982/*
 983 * Free a 0-order page
 984 */
 985static void free_hot_cold_page(struct page *page, int cold)
 986{
 987        struct zone *zone = page_zone(page);
 988        struct per_cpu_pages *pcp;
 989        unsigned long flags;
 990
 991        if (PageAnon(page))
 992                page->mapping = NULL;
 993        if (free_pages_check(page))
 994                return;
 995
 996        if (!PageHighMem(page)) {
 997                debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
 998                debug_check_no_obj_freed(page_address(page), PAGE_SIZE);
 999        }
1000        arch_free_page(page, 0);
1001        kernel_map_pages(page, 1, 0);
1002
1003        pcp = &zone_pcp(zone, get_cpu())->pcp;
1004        local_irq_save(flags);
1005        __count_vm_event(PGFREE);
1006        if (cold)
1007                list_add_tail(&page->lru, &pcp->list);
1008        else
1009                list_add(&page->lru, &pcp->list);
1010        set_page_private(page, get_pageblock_migratetype(page));
1011        pcp->count++;
1012        if (pcp->count >= pcp->high) {
1013                free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
1014                pcp->count -= pcp->batch;
1015        }
1016        local_irq_restore(flags);
1017        put_cpu();
1018}
1019
1020void free_hot_page(struct page *page)
1021{
1022        free_hot_cold_page(page, 0);
1023}
1024        
1025void free_cold_page(struct page *page)
1026{
1027        free_hot_cold_page(page, 1);
1028}
1029
1030/*
1031 * split_page takes a non-compound higher-order page, and splits it into
1032 * n (1<<order) sub-pages: page[0..n]
1033 * Each sub-page must be freed individually.
1034 *
1035 * Note: this is probably too low level an operation for use in drivers.
1036 * Please consult with lkml before using this in your driver.
1037 */
1038void split_page(struct page *page, unsigned int order)
1039{
1040        int i;
1041
1042        VM_BUG_ON(PageCompound(page));
1043        VM_BUG_ON(!page_count(page));
1044        for (i = 1; i < (1 << order); i++)
1045                set_page_refcounted(page + i);
1046}
1047
1048/*
1049 * Really, prep_compound_page() should be called from __rmqueue_bulk().  But
1050 * we cheat by calling it from here, in the order > 0 path.  Saves a branch
1051 * or two.
1052 */
1053static struct page *buffered_rmqueue(struct zone *preferred_zone,
1054                        struct zone *zone, int order, gfp_t gfp_flags)
1055{
1056        unsigned long flags;
1057        struct page *page;
1058        int cold = !!(gfp_flags & __GFP_COLD);
1059        int cpu;
1060        int migratetype = allocflags_to_migratetype(gfp_flags);
1061
1062again:
1063        cpu  = get_cpu();
1064        if (likely(order == 0)) {
1065                struct per_cpu_pages *pcp;
1066
1067                pcp = &zone_pcp(zone, cpu)->pcp;
1068                local_irq_save(flags);
1069                if (!pcp->count) {
1070                        pcp->count = rmqueue_bulk(zone, 0,
1071                                        pcp->batch, &pcp->list, migratetype);
1072                        if (unlikely(!pcp->count))
1073                                goto failed;
1074                }
1075
1076                /* Find a page of the appropriate migrate type */
1077                if (cold) {
1078                        list_for_each_entry_reverse(page, &pcp->list, lru)
1079                                if (page_private(page) == migratetype)
1080                                        break;
1081                } else {
1082                        list_for_each_entry(page, &pcp->list, lru)
1083                                if (page_private(page) == migratetype)
1084                                        break;
1085                }
1086
1087                /* Allocate more to the pcp list if necessary */
1088                if (unlikely(&page->lru == &pcp->list)) {
1089                        pcp->count += rmqueue_bulk(zone, 0,
1090                                        pcp->batch, &pcp->list, migratetype);
1091                        page = list_entry(pcp->list.next, struct page, lru);
1092                }
1093
1094                list_del(&page->lru);
1095                pcp->count--;
1096        } else {
1097                spin_lock_irqsave(&zone->lock, flags);
1098                page = __rmqueue(zone, order, migratetype);
1099                spin_unlock(&zone->lock);
1100                if (!page)
1101                        goto failed;
1102        }
1103
1104        __count_zone_vm_events(PGALLOC, zone, 1 << order);
1105        zone_statistics(preferred_zone, zone);
1106        local_irq_restore(flags);
1107        put_cpu();
1108
1109        VM_BUG_ON(bad_range(zone, page));
1110        if (prep_new_page(page, order, gfp_flags))
1111                goto again;
1112        return page;
1113
1114failed:
1115        local_irq_restore(flags);
1116        put_cpu();
1117        return NULL;
1118}
1119
1120#define ALLOC_NO_WATERMARKS     0x01 /* don't check watermarks at all */
1121#define ALLOC_WMARK_MIN         0x02 /* use pages_min watermark */
1122#define ALLOC_WMARK_LOW         0x04 /* use pages_low watermark */
1123#define ALLOC_WMARK_HIGH        0x08 /* use pages_high watermark */
1124#define ALLOC_HARDER            0x10 /* try to alloc harder */
1125#define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
1126#define ALLOC_CPUSET            0x40 /* check for correct cpuset */
1127
1128#ifdef CONFIG_FAIL_PAGE_ALLOC
1129
1130static struct fail_page_alloc_attr {
1131        struct fault_attr attr;
1132
1133        u32 ignore_gfp_highmem;
1134        u32 ignore_gfp_wait;
1135        u32 min_order;
1136
1137#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1138
1139        struct dentry *ignore_gfp_highmem_file;
1140        struct dentry *ignore_gfp_wait_file;
1141        struct dentry *min_order_file;
1142
1143#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1144
1145} fail_page_alloc = {
1146        .attr = FAULT_ATTR_INITIALIZER,
1147        .ignore_gfp_wait = 1,
1148        .ignore_gfp_highmem = 1,
1149        .min_order = 1,
1150};
1151
1152static int __init setup_fail_page_alloc(char *str)
1153{
1154        return setup_fault_attr(&fail_page_alloc.attr, str);
1155}
1156__setup("fail_page_alloc=", setup_fail_page_alloc);
1157
1158static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1159{
1160        if (order < fail_page_alloc.min_order)
1161                return 0;
1162        if (gfp_mask & __GFP_NOFAIL)
1163                return 0;
1164        if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1165                return 0;
1166        if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1167                return 0;
1168
1169        return should_fail(&fail_page_alloc.attr, 1 << order);
1170}
1171
1172#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1173
1174static int __init fail_page_alloc_debugfs(void)
1175{
1176        mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1177        struct dentry *dir;
1178        int err;
1179
1180        err = init_fault_attr_dentries(&fail_page_alloc.attr,
1181                                       "fail_page_alloc");
1182        if (err)
1183                return err;
1184        dir = fail_page_alloc.attr.dentries.dir;
1185
1186        fail_page_alloc.ignore_gfp_wait_file =
1187                debugfs_create_bool("ignore-gfp-wait", mode, dir,
1188                                      &fail_page_alloc.ignore_gfp_wait);
1189
1190        fail_page_alloc.ignore_gfp_highmem_file =
1191                debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1192                                      &fail_page_alloc.ignore_gfp_highmem);
1193        fail_page_alloc.min_order_file =
1194                debugfs_create_u32("min-order", mode, dir,
1195                                   &fail_page_alloc.min_order);
1196
1197        if (!fail_page_alloc.ignore_gfp_wait_file ||
1198            !fail_page_alloc.ignore_gfp_highmem_file ||
1199            !fail_page_alloc.min_order_file) {
1200                err = -ENOMEM;
1201                debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
1202                debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
1203                debugfs_remove(fail_page_alloc.min_order_file);
1204                cleanup_fault_attr_dentries(&fail_page_alloc.attr);
1205        }
1206
1207        return err;
1208}
1209
1210late_initcall(fail_page_alloc_debugfs);
1211
1212#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1213
1214#else /* CONFIG_FAIL_PAGE_ALLOC */
1215
1216static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1217{
1218        return 0;
1219}
1220
1221#endif /* CONFIG_FAIL_PAGE_ALLOC */
1222
1223/*
1224 * Return 1 if free pages are above 'mark'. This takes into account the order
1225 * of the allocation.
1226 */
1227int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1228                      int classzone_idx, int alloc_flags)
1229{
1230        /* free_pages my go negative - that's OK */
1231        long min = mark;
1232        long free_pages = zone_page_state(z, NR_FREE_PAGES) - (1 << order) + 1;
1233        int o;
1234
1235        if (alloc_flags & ALLOC_HIGH)
1236                min -= min / 2;
1237        if (alloc_flags & ALLOC_HARDER)
1238                min -= min / 4;
1239
1240        if (free_pages <= min + z->lowmem_reserve[classzone_idx])
1241                return 0;
1242        for (o = 0; o < order; o++) {
1243                /* At the next order, this order's pages become unavailable */
1244                free_pages -= z->free_area[o].nr_free << o;
1245
1246                /* Require fewer higher order pages to be free */
1247                min >>= 1;
1248
1249                if (free_pages <= min)
1250                        return 0;
1251        }
1252        return 1;
1253}
1254
1255#ifdef CONFIG_NUMA
1256/*
1257 * zlc_setup - Setup for "zonelist cache".  Uses cached zone data to
1258 * skip over zones that are not allowed by the cpuset, or that have
1259 * been recently (in last second) found to be nearly full.  See further
1260 * comments in mmzone.h.  Reduces cache footprint of zonelist scans
1261 * that have to skip over a lot of full or unallowed zones.
1262 *
1263 * If the zonelist cache is present in the passed in zonelist, then
1264 * returns a pointer to the allowed node mask (either the current
1265 * tasks mems_allowed, or node_states[N_HIGH_MEMORY].)
1266 *
1267 * If the zonelist cache is not available for this zonelist, does
1268 * nothing and returns NULL.
1269 *
1270 * If the fullzones BITMAP in the zonelist cache is stale (more than
1271 * a second since last zap'd) then we zap it out (clear its bits.)
1272 *
1273 * We hold off even calling zlc_setup, until after we've checked the
1274 * first zone in the zonelist, on the theory that most allocations will
1275 * be satisfied from that first zone, so best to examine that zone as
1276 * quickly as we can.
1277 */
1278static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1279{
1280        struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1281        nodemask_t *allowednodes;       /* zonelist_cache approximation */
1282
1283        zlc = zonelist->zlcache_ptr;
1284        if (!zlc)
1285                return NULL;
1286
1287        if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1288                bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1289                zlc->last_full_zap = jiffies;
1290        }
1291
1292        allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1293                                        &cpuset_current_mems_allowed :
1294                                        &node_states[N_HIGH_MEMORY];
1295        return allowednodes;
1296}
1297
1298/*
1299 * Given 'z' scanning a zonelist, run a couple of quick checks to see
1300 * if it is worth looking at further for free memory:
1301 *  1) Check that the zone isn't thought to be full (doesn't have its
1302 *     bit set in the zonelist_cache fullzones BITMAP).
1303 *  2) Check that the zones node (obtained from the zonelist_cache
1304 *     z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1305 * Return true (non-zero) if zone is worth looking at further, or
1306 * else return false (zero) if it is not.
1307 *
1308 * This check -ignores- the distinction between various watermarks,
1309 * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ...  If a zone is
1310 * found to be full for any variation of these watermarks, it will
1311 * be considered full for up to one second by all requests, unless
1312 * we are so low on memory on all allowed nodes that we are forced
1313 * into the second scan of the zonelist.
1314 *
1315 * In the second scan we ignore this zonelist cache and exactly
1316 * apply the watermarks to all zones, even it is slower to do so.
1317 * We are low on memory in the second scan, and should leave no stone
1318 * unturned looking for a free page.
1319 */
1320static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1321                                                nodemask_t *allowednodes)
1322{
1323        struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1324        int i;                          /* index of *z in zonelist zones */
1325        int n;                          /* node that zone *z is on */
1326
1327        zlc = zonelist->zlcache_ptr;
1328        if (!zlc)
1329                return 1;
1330
1331        i = z - zonelist->_zonerefs;
1332        n = zlc->z_to_n[i];
1333
1334        /* This zone is worth trying if it is allowed but not full */
1335        return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1336}
1337
1338/*
1339 * Given 'z' scanning a zonelist, set the corresponding bit in
1340 * zlc->fullzones, so that subsequent attempts to allocate a page
1341 * from that zone don't waste time re-examining it.
1342 */
1343static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1344{
1345        struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1346        int i;                          /* index of *z in zonelist zones */
1347
1348        zlc = zonelist->zlcache_ptr;
1349        if (!zlc)
1350                return;
1351
1352        i = z - zonelist->_zonerefs;
1353
1354        set_bit(i, zlc->fullzones);
1355}
1356
1357#else   /* CONFIG_NUMA */
1358
1359static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1360{
1361        return NULL;
1362}
1363
1364static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1365                                nodemask_t *allowednodes)
1366{
1367        return 1;
1368}
1369
1370static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1371{
1372}
1373#endif  /* CONFIG_NUMA */
1374
1375/*
1376 * get_page_from_freelist goes through the zonelist trying to allocate
1377 * a page.
1378 */
1379static struct page *
1380get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1381                struct zonelist *zonelist, int high_zoneidx, int alloc_flags)
1382{
1383        struct zoneref *z;
1384        struct page *page = NULL;
1385        int classzone_idx;
1386        struct zone *zone, *preferred_zone;
1387        nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1388        int zlc_active = 0;             /* set if using zonelist_cache */
1389        int did_zlc_setup = 0;          /* just call zlc_setup() one time */
1390
1391        (void)first_zones_zonelist(zonelist, high_zoneidx, nodemask,
1392                                                        &preferred_zone);
1393        if (!preferred_zone)
1394                return NULL;
1395
1396        classzone_idx = zone_idx(preferred_zone);
1397
1398zonelist_scan:
1399        /*
1400         * Scan zonelist, looking for a zone with enough free.
1401         * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1402         */
1403        for_each_zone_zonelist_nodemask(zone, z, zonelist,
1404                                                high_zoneidx, nodemask) {
1405                if (NUMA_BUILD && zlc_active &&
1406                        !zlc_zone_worth_trying(zonelist, z, allowednodes))
1407                                continue;
1408                if ((alloc_flags & ALLOC_CPUSET) &&
1409                        !cpuset_zone_allowed_softwall(zone, gfp_mask))
1410                                goto try_next_zone;
1411
1412                if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
1413                        unsigned long mark;
1414                        if (alloc_flags & ALLOC_WMARK_MIN)
1415                                mark = zone->pages_min;
1416                        else if (alloc_flags & ALLOC_WMARK_LOW)
1417                                mark = zone->pages_low;
1418                        else
1419                                mark = zone->pages_high;
1420                        if (!zone_watermark_ok(zone, order, mark,
1421                                    classzone_idx, alloc_flags)) {
1422                                if (!zone_reclaim_mode ||
1423                                    !zone_reclaim(zone, gfp_mask, order))
1424                                        goto this_zone_full;
1425                        }
1426                }
1427
1428                page = buffered_rmqueue(preferred_zone, zone, order, gfp_mask);
1429                if (page)
1430                        break;
1431this_zone_full:
1432                if (NUMA_BUILD)
1433                        zlc_mark_zone_full(zonelist, z);
1434try_next_zone:
1435                if (NUMA_BUILD && !did_zlc_setup) {
1436                        /* we do zlc_setup after the first zone is tried */
1437                        allowednodes = zlc_setup(zonelist, alloc_flags);
1438                        zlc_active = 1;
1439                        did_zlc_setup = 1;
1440                }
1441        }
1442
1443        if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
1444                /* Disable zlc cache for second zonelist scan */
1445                zlc_active = 0;
1446                goto zonelist_scan;
1447        }
1448        return page;
1449}
1450
1451/*
1452 * This is the 'heart' of the zoned buddy allocator.
1453 */
1454struct page *
1455__alloc_pages_internal(gfp_t gfp_mask, unsigned int order,
1456                        struct zonelist *zonelist, nodemask_t *nodemask)
1457{
1458        const gfp_t wait = gfp_mask & __GFP_WAIT;
1459        enum zone_type high_zoneidx = gfp_zone(gfp_mask);
1460        struct zoneref *z;
1461        struct zone *zone;
1462        struct page *page;
1463        struct reclaim_state reclaim_state;
1464        struct task_struct *p = current;
1465        int do_retry;
1466        int alloc_flags;
1467        unsigned long did_some_progress;
1468        unsigned long pages_reclaimed = 0;
1469
1470        might_sleep_if(wait);
1471
1472        if (should_fail_alloc_page(gfp_mask, order))
1473                return NULL;
1474
1475restart:
1476        z = zonelist->_zonerefs;  /* the list of zones suitable for gfp_mask */
1477
1478        if (unlikely(!z->zone)) {
1479                /*
1480                 * Happens if we have an empty zonelist as a result of
1481                 * GFP_THISNODE being used on a memoryless node
1482                 */
1483                return NULL;
1484        }
1485
1486        page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
1487                        zonelist, high_zoneidx, ALLOC_WMARK_LOW|ALLOC_CPUSET);
1488        if (page)
1489                goto got_pg;
1490
1491        /*
1492         * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
1493         * __GFP_NOWARN set) should not cause reclaim since the subsystem
1494         * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
1495         * using a larger set of nodes after it has established that the
1496         * allowed per node queues are empty and that nodes are
1497         * over allocated.
1498         */
1499        if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
1500                goto nopage;
1501
1502        for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
1503                wakeup_kswapd(zone, order);
1504
1505        /*
1506         * OK, we're below the kswapd watermark and have kicked background
1507         * reclaim. Now things get more complex, so set up alloc_flags according
1508         * to how we want to proceed.
1509         *
1510         * The caller may dip into page reserves a bit more if the caller
1511         * cannot run direct reclaim, or if the caller has realtime scheduling
1512         * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
1513         * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
1514         */
1515        alloc_flags = ALLOC_WMARK_MIN;
1516        if ((unlikely(rt_task(p)) && !in_interrupt()) || !wait)
1517                alloc_flags |= ALLOC_HARDER;
1518        if (gfp_mask & __GFP_HIGH)
1519                alloc_flags |= ALLOC_HIGH;
1520        if (wait)
1521                alloc_flags |= ALLOC_CPUSET;
1522
1523        /*
1524         * Go through the zonelist again. Let __GFP_HIGH and allocations
1525         * coming from realtime tasks go deeper into reserves.
1526         *
1527         * This is the last chance, in general, before the goto nopage.
1528         * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
1529         * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1530         */
1531        page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
1532                                                high_zoneidx, alloc_flags);
1533        if (page)
1534                goto got_pg;
1535
1536        /* This allocation should allow future memory freeing. */
1537
1538rebalance:
1539        if (((p->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE)))
1540                        && !in_interrupt()) {
1541                if (!(gfp_mask & __GFP_NOMEMALLOC)) {
1542nofail_alloc:
1543                        /* go through the zonelist yet again, ignoring mins */
1544                        page = get_page_from_freelist(gfp_mask, nodemask, order,
1545                                zonelist, high_zoneidx, ALLOC_NO_WATERMARKS);
1546                        if (page)
1547                                goto got_pg;
1548                        if (gfp_mask & __GFP_NOFAIL) {
1549                                congestion_wait(WRITE, HZ/50);
1550                                goto nofail_alloc;
1551                        }
1552                }
1553                goto nopage;
1554        }
1555
1556        /* Atomic allocations - we can't balance anything */
1557        if (!wait)
1558                goto nopage;
1559
1560        cond_resched();
1561
1562        /* We now go into synchronous reclaim */
1563        cpuset_memory_pressure_bump();
1564        /*
1565         * The task's cpuset might have expanded its set of allowable nodes
1566         */
1567        cpuset_update_task_memory_state();
1568        p->flags |= PF_MEMALLOC;
1569        reclaim_state.reclaimed_slab = 0;
1570        p->reclaim_state = &reclaim_state;
1571
1572        did_some_progress = try_to_free_pages(zonelist, order, gfp_mask);
1573
1574        p->reclaim_state = NULL;
1575        p->flags &= ~PF_MEMALLOC;
1576
1577        cond_resched();
1578
1579        if (order != 0)
1580                drain_all_pages();
1581
1582        if (likely(did_some_progress)) {
1583                page = get_page_from_freelist(gfp_mask, nodemask, order,
1584                                        zonelist, high_zoneidx, alloc_flags);
1585                if (page)
1586                        goto got_pg;
1587        } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
1588                if (!try_set_zone_oom(zonelist, gfp_mask)) {
1589                        schedule_timeout_uninterruptible(1);
1590                        goto restart;
1591                }
1592
1593                /*
1594                 * Go through the zonelist yet one more time, keep
1595                 * very high watermark here, this is only to catch
1596                 * a parallel oom killing, we must fail if we're still
1597                 * under heavy pressure.
1598                 */
1599                page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
1600                        order, zonelist, high_zoneidx,
1601                        ALLOC_WMARK_HIGH|ALLOC_CPUSET);
1602                if (page) {
1603                        clear_zonelist_oom(zonelist, gfp_mask);
1604                        goto got_pg;
1605                }
1606
1607                /* The OOM killer will not help higher order allocs so fail */
1608                if (order > PAGE_ALLOC_COSTLY_ORDER) {
1609                        clear_zonelist_oom(zonelist, gfp_mask);
1610                        goto nopage;
1611                }
1612
1613                out_of_memory(zonelist, gfp_mask, order);
1614                clear_zonelist_oom(zonelist, gfp_mask);
1615                goto restart;
1616        }
1617
1618        /*
1619         * Don't let big-order allocations loop unless the caller explicitly
1620         * requests that.  Wait for some write requests to complete then retry.
1621         *
1622         * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
1623         * means __GFP_NOFAIL, but that may not be true in other
1624         * implementations.
1625         *
1626         * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
1627         * specified, then we retry until we no longer reclaim any pages
1628         * (above), or we've reclaimed an order of pages at least as
1629         * large as the allocation's order. In both cases, if the
1630         * allocation still fails, we stop retrying.
1631         */
1632        pages_reclaimed += did_some_progress;
1633        do_retry = 0;
1634        if (!(gfp_mask & __GFP_NORETRY)) {
1635                if (order <= PAGE_ALLOC_COSTLY_ORDER) {
1636                        do_retry = 1;
1637                } else {
1638                        if (gfp_mask & __GFP_REPEAT &&
1639                                pages_reclaimed < (1 << order))
1640                                        do_retry = 1;
1641                }
1642                if (gfp_mask & __GFP_NOFAIL)
1643                        do_retry = 1;
1644        }
1645        if (do_retry) {
1646                congestion_wait(WRITE, HZ/50);
1647                goto rebalance;
1648        }
1649
1650nopage:
1651        if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
1652                printk(KERN_WARNING "%s: page allocation failure."
1653                        " order:%d, mode:0x%x\n",
1654                        p->comm, order, gfp_mask);
1655                dump_stack();
1656                show_mem();
1657        }
1658got_pg:
1659        return page;
1660}
1661EXPORT_SYMBOL(__alloc_pages_internal);
1662
1663/*
1664 * Common helper functions.
1665 */
1666unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
1667{
1668        struct page * page;
1669        page = alloc_pages(gfp_mask, order);
1670        if (!page)
1671                return 0;
1672        return (unsigned long) page_address(page);
1673}
1674
1675EXPORT_SYMBOL(__get_free_pages);
1676
1677unsigned long get_zeroed_page(gfp_t gfp_mask)
1678{
1679        struct page * page;
1680
1681        /*
1682         * get_zeroed_page() returns a 32-bit address, which cannot represent
1683         * a highmem page
1684         */
1685        VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
1686
1687        page = alloc_pages(gfp_mask | __GFP_ZERO, 0);
1688        if (page)
1689                return (unsigned long) page_address(page);
1690        return 0;
1691}
1692
1693EXPORT_SYMBOL(get_zeroed_page);
1694
1695void __pagevec_free(struct pagevec *pvec)
1696{
1697        int i = pagevec_count(pvec);
1698
1699        while (--i >= 0)
1700                free_hot_cold_page(pvec->pages[i], pvec->cold);
1701}
1702
1703void __free_pages(struct page *page, unsigned int order)
1704{
1705        if (put_page_testzero(page)) {
1706                if (order == 0)
1707                        free_hot_page(page);
1708                else
1709                        __free_pages_ok(page, order);
1710        }
1711}
1712
1713EXPORT_SYMBOL(__free_pages);
1714
1715void free_pages(unsigned long addr, unsigned int order)
1716{
1717        if (addr != 0) {
1718                VM_BUG_ON(!virt_addr_valid((void *)addr));
1719                __free_pages(virt_to_page((void *)addr), order);
1720        }
1721}
1722
1723EXPORT_SYMBOL(free_pages);
1724
1725/**
1726 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
1727 * @size: the number of bytes to allocate
1728 * @gfp_mask: GFP flags for the allocation
1729 *
1730 * This function is similar to alloc_pages(), except that it allocates the
1731 * minimum number of pages to satisfy the request.  alloc_pages() can only
1732 * allocate memory in power-of-two pages.
1733 *
1734 * This function is also limited by MAX_ORDER.
1735 *
1736 * Memory allocated by this function must be released by free_pages_exact().
1737 */
1738void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
1739{
1740        unsigned int order = get_order(size);
1741        unsigned long addr;
1742
1743        addr = __get_free_pages(gfp_mask, order);
1744        if (addr) {
1745                unsigned long alloc_end = addr + (PAGE_SIZE << order);
1746                unsigned long used = addr + PAGE_ALIGN(size);
1747
1748                split_page(virt_to_page(addr), order);
1749                while (used < alloc_end) {
1750                        free_page(used);
1751                        used += PAGE_SIZE;
1752                }
1753        }
1754
1755        return (void *)addr;
1756}
1757EXPORT_SYMBOL(alloc_pages_exact);
1758
1759/**
1760 * free_pages_exact - release memory allocated via alloc_pages_exact()
1761 * @virt: the value returned by alloc_pages_exact.
1762 * @size: size of allocation, same value as passed to alloc_pages_exact().
1763 *
1764 * Release the memory allocated by a previous call to alloc_pages_exact.
1765 */
1766void free_pages_exact(void *virt, size_t size)
1767{
1768        unsigned long addr = (unsigned long)virt;
1769        unsigned long end = addr + PAGE_ALIGN(size);
1770
1771        while (addr < end) {
1772                free_page(addr);
1773                addr += PAGE_SIZE;
1774        }
1775}
1776EXPORT_SYMBOL(free_pages_exact);
1777
1778static unsigned int nr_free_zone_pages(int offset)
1779{
1780        struct zoneref *z;
1781        struct zone *zone;
1782
1783        /* Just pick one node, since fallback list is circular */
1784        unsigned int sum = 0;
1785
1786        struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
1787
1788        for_each_zone_zonelist(zone, z, zonelist, offset) {
1789                unsigned long size = zone->present_pages;
1790                unsigned long high = zone->pages_high;
1791                if (size > high)
1792                        sum += size - high;
1793        }
1794
1795        return sum;
1796}
1797
1798/*
1799 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
1800 */
1801unsigned int nr_free_buffer_pages(void)
1802{
1803        return nr_free_zone_pages(gfp_zone(GFP_USER));
1804}
1805EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
1806
1807/*
1808 * Amount of free RAM allocatable within all zones
1809 */
1810unsigned int nr_free_pagecache_pages(void)
1811{
1812        return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
1813}
1814
1815static inline void show_node(struct zone *zone)
1816{
1817        if (NUMA_BUILD)
1818                printk("Node %d ", zone_to_nid(zone));
1819}
1820
1821void si_meminfo(struct sysinfo *val)
1822{
1823        val->totalram = totalram_pages;
1824        val->sharedram = 0;
1825        val->freeram = global_page_state(NR_FREE_PAGES);
1826        val->bufferram = nr_blockdev_pages();
1827        val->totalhigh = totalhigh_pages;
1828        val->freehigh = nr_free_highpages();
1829        val->mem_unit = PAGE_SIZE;
1830}
1831
1832EXPORT_SYMBOL(si_meminfo);
1833
1834#ifdef CONFIG_NUMA
1835void si_meminfo_node(struct sysinfo *val, int nid)
1836{
1837        pg_data_t *pgdat = NODE_DATA(nid);
1838
1839        val->totalram = pgdat->node_present_pages;
1840        val->freeram = node_page_state(nid, NR_FREE_PAGES);
1841#ifdef CONFIG_HIGHMEM
1842        val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
1843        val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
1844                        NR_FREE_PAGES);
1845#else
1846        val->totalhigh = 0;
1847        val->freehigh = 0;
1848#endif
1849        val->mem_unit = PAGE_SIZE;
1850}
1851#endif
1852
1853#define K(x) ((x) << (PAGE_SHIFT-10))
1854
1855/*
1856 * Show free area list (used inside shift_scroll-lock stuff)
1857 * We also calculate the percentage fragmentation. We do this by counting the
1858 * memory on each free list with the exception of the first item on the list.
1859 */
1860void show_free_areas(void)
1861{
1862        int cpu;
1863        struct zone *zone;
1864
1865        for_each_zone(zone) {
1866                if (!populated_zone(zone))
1867                        continue;
1868
1869                show_node(zone);
1870                printk("%s per-cpu:\n", zone->name);
1871
1872                for_each_online_cpu(cpu) {
1873                        struct per_cpu_pageset *pageset;
1874
1875                        pageset = zone_pcp(zone, cpu);
1876
1877                        printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
1878                               cpu, pageset->pcp.high,
1879                               pageset->pcp.batch, pageset->pcp.count);
1880                }
1881        }
1882
1883        printk("Active_anon:%lu active_file:%lu inactive_anon:%lu\n"
1884                " inactive_file:%lu"
1885//TODO:  check/adjust line lengths
1886#ifdef CONFIG_UNEVICTABLE_LRU
1887                " unevictable:%lu"
1888#endif
1889                " dirty:%lu writeback:%lu unstable:%lu\n"
1890                " free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n",
1891                global_page_state(NR_ACTIVE_ANON),
1892                global_page_state(NR_ACTIVE_FILE),
1893                global_page_state(NR_INACTIVE_ANON),
1894                global_page_state(NR_INACTIVE_FILE),
1895#ifdef CONFIG_UNEVICTABLE_LRU
1896                global_page_state(NR_UNEVICTABLE),
1897#endif
1898                global_page_state(NR_FILE_DIRTY),
1899                global_page_state(NR_WRITEBACK),
1900                global_page_state(NR_UNSTABLE_NFS),
1901                global_page_state(NR_FREE_PAGES),
1902                global_page_state(NR_SLAB_RECLAIMABLE) +
1903                        global_page_state(NR_SLAB_UNRECLAIMABLE),
1904                global_page_state(NR_FILE_MAPPED),
1905                global_page_state(NR_PAGETABLE),
1906                global_page_state(NR_BOUNCE));
1907
1908        for_each_zone(zone) {
1909                int i;
1910
1911                if (!populated_zone(zone))
1912                        continue;
1913
1914                show_node(zone);
1915                printk("%s"
1916                        " free:%lukB"
1917                        " min:%lukB"
1918                        " low:%lukB"
1919                        " high:%lukB"
1920                        " active_anon:%lukB"
1921                        " inactive_anon:%lukB"
1922                        " active_file:%lukB"
1923                        " inactive_file:%lukB"
1924#ifdef CONFIG_UNEVICTABLE_LRU
1925                        " unevictable:%lukB"
1926#endif
1927                        " present:%lukB"
1928                        " pages_scanned:%lu"
1929                        " all_unreclaimable? %s"
1930                        "\n",
1931                        zone->name,
1932                        K(zone_page_state(zone, NR_FREE_PAGES)),
1933                        K(zone->pages_min),
1934                        K(zone->pages_low),
1935                        K(zone->pages_high),
1936                        K(zone_page_state(zone, NR_ACTIVE_ANON)),
1937                        K(zone_page_state(zone, NR_INACTIVE_ANON)),
1938                        K(zone_page_state(zone, NR_ACTIVE_FILE)),
1939                        K(zone_page_state(zone, NR_INACTIVE_FILE)),
1940#ifdef CONFIG_UNEVICTABLE_LRU
1941                        K(zone_page_state(zone, NR_UNEVICTABLE)),
1942#endif
1943                        K(zone->present_pages),
1944                        zone->pages_scanned,
1945                        (zone_is_all_unreclaimable(zone) ? "yes" : "no")
1946                        );
1947                printk("lowmem_reserve[]:");
1948                for (i = 0; i < MAX_NR_ZONES; i++)
1949                        printk(" %lu", zone->lowmem_reserve[i]);
1950                printk("\n");
1951        }
1952
1953        for_each_zone(zone) {
1954                unsigned long nr[MAX_ORDER], flags, order, total = 0;
1955
1956                if (!populated_zone(zone))
1957                        continue;
1958
1959                show_node(zone);
1960                printk("%s: ", zone->name);
1961
1962                spin_lock_irqsave(&zone->lock, flags);
1963                for (order = 0; order < MAX_ORDER; order++) {
1964                        nr[order] = zone->free_area[order].nr_free;
1965                        total += nr[order] << order;
1966                }
1967                spin_unlock_irqrestore(&zone->lock, flags);
1968                for (order = 0; order < MAX_ORDER; order++)
1969                        printk("%lu*%lukB ", nr[order], K(1UL) << order);
1970                printk("= %lukB\n", K(total));
1971        }
1972
1973        printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
1974
1975        show_swap_cache_info();
1976}
1977
1978static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
1979{
1980        zoneref->zone = zone;
1981        zoneref->zone_idx = zone_idx(zone);
1982}
1983
1984/*
1985 * Builds allocation fallback zone lists.
1986 *
1987 * Add all populated zones of a node to the zonelist.
1988 */
1989static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
1990                                int nr_zones, enum zone_type zone_type)
1991{
1992        struct zone *zone;
1993
1994        BUG_ON(zone_type >= MAX_NR_ZONES);
1995        zone_type++;
1996
1997        do {
1998                zone_type--;
1999                zone = pgdat->node_zones + zone_type;
2000                if (populated_zone(zone)) {
2001                        zoneref_set_zone(zone,
2002                                &zonelist->_zonerefs[nr_zones++]);
2003                        check_highest_zone(zone_type);
2004                }
2005
2006        } while (zone_type);
2007        return nr_zones;
2008}
2009
2010
2011/*
2012 *  zonelist_order:
2013 *  0 = automatic detection of better ordering.
2014 *  1 = order by ([node] distance, -zonetype)
2015 *  2 = order by (-zonetype, [node] distance)
2016 *
2017 *  If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
2018 *  the same zonelist. So only NUMA can configure this param.
2019 */
2020#define ZONELIST_ORDER_DEFAULT  0
2021#define ZONELIST_ORDER_NODE     1
2022#define ZONELIST_ORDER_ZONE     2
2023
2024/* zonelist order in the kernel.
2025 * set_zonelist_order() will set this to NODE or ZONE.
2026 */
2027static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
2028static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
2029
2030
2031#ifdef CONFIG_NUMA
2032/* The value user specified ....changed by config */
2033static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2034/* string for sysctl */
2035#define NUMA_ZONELIST_ORDER_LEN 16
2036char numa_zonelist_order[16] = "default";
2037
2038/*
2039 * interface for configure zonelist ordering.
2040 * command line option "numa_zonelist_order"
2041 *      = "[dD]efault   - default, automatic configuration.
2042 *      = "[nN]ode      - order by node locality, then by zone within node
2043 *      = "[zZ]one      - order by zone, then by locality within zone
2044 */
2045
2046static int __parse_numa_zonelist_order(char *s)
2047{
2048        if (*s == 'd' || *s == 'D') {
2049                user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2050        } else if (*s == 'n' || *s == 'N') {
2051                user_zonelist_order = ZONELIST_ORDER_NODE;
2052        } else if (*s == 'z' || *s == 'Z') {
2053                user_zonelist_order = ZONELIST_ORDER_ZONE;
2054        } else {
2055                printk(KERN_WARNING
2056                        "Ignoring invalid numa_zonelist_order value:  "
2057                        "%s\n", s);
2058                return -EINVAL;
2059        }
2060        return 0;
2061}
2062
2063static __init int setup_numa_zonelist_order(char *s)
2064{
2065        if (s)
2066                return __parse_numa_zonelist_order(s);
2067        return 0;
2068}
2069early_param("numa_zonelist_order", setup_numa_zonelist_order);
2070
2071/*
2072 * sysctl handler for numa_zonelist_order
2073 */
2074int numa_zonelist_order_handler(ctl_table *table, int write,
2075                struct file *file, void __user *buffer, size_t *length,
2076                loff_t *ppos)
2077{
2078        char saved_string[NUMA_ZONELIST_ORDER_LEN];
2079        int ret;
2080
2081        if (write)
2082                strncpy(saved_string, (char*)table->data,
2083                        NUMA_ZONELIST_ORDER_LEN);
2084        ret = proc_dostring(table, write, file, buffer, length, ppos);
2085        if (ret)
2086                return ret;
2087        if (write) {
2088                int oldval = user_zonelist_order;
2089                if (__parse_numa_zonelist_order((char*)table->data)) {
2090                        /*
2091                         * bogus value.  restore saved string
2092                         */
2093                        strncpy((char*)table->data, saved_string,
2094                                NUMA_ZONELIST_ORDER_LEN);
2095                        user_zonelist_order = oldval;
2096                } else if (oldval != user_zonelist_order)
2097                        build_all_zonelists();
2098        }
2099        return 0;
2100}
2101
2102
2103#define MAX_NODE_LOAD (num_online_nodes())
2104static int node_load[MAX_NUMNODES];
2105
2106/**
2107 * find_next_best_node - find the next node that should appear in a given node's fallback list
2108 * @node: node whose fallback list we're appending
2109 * @used_node_mask: nodemask_t of already used nodes
2110 *
2111 * We use a number of factors to determine which is the next node that should
2112 * appear on a given node's fallback list.  The node should not have appeared
2113 * already in @node's fallback list, and it should be the next closest node
2114 * according to the distance array (which contains arbitrary distance values
2115 * from each node to each node in the system), and should also prefer nodes
2116 * with no CPUs, since presumably they'll have very little allocation pressure
2117 * on them otherwise.
2118 * It returns -1 if no node is found.
2119 */
2120static int find_next_best_node(int node, nodemask_t *used_node_mask)
2121{
2122        int n, val;
2123        int min_val = INT_MAX;
2124        int best_node = -1;
2125        node_to_cpumask_ptr(tmp, 0);
2126
2127        /* Use the local node if we haven't already */
2128        if (!node_isset(node, *used_node_mask)) {
2129                node_set(node, *used_node_mask);
2130                return node;
2131        }
2132
2133        for_each_node_state(n, N_HIGH_MEMORY) {
2134
2135                /* Don't want a node to appear more than once */
2136                if (node_isset(n, *used_node_mask))
2137                        continue;
2138
2139                /* Use the distance array to find the distance */
2140                val = node_distance(node, n);
2141
2142                /* Penalize nodes under us ("prefer the next node") */
2143                val += (n < node);
2144
2145                /* Give preference to headless and unused nodes */
2146                node_to_cpumask_ptr_next(tmp, n);
2147                if (!cpus_empty(*tmp))
2148                        val += PENALTY_FOR_NODE_WITH_CPUS;
2149
2150                /* Slight preference for less loaded node */
2151                val *= (MAX_NODE_LOAD*MAX_NUMNODES);
2152                val += node_load[n];
2153
2154                if (val < min_val) {
2155                        min_val = val;
2156                        best_node = n;
2157                }
2158        }
2159
2160        if (best_node >= 0)
2161                node_set(best_node, *used_node_mask);
2162
2163        return best_node;
2164}
2165
2166
2167/*
2168 * Build zonelists ordered by node and zones within node.
2169 * This results in maximum locality--normal zone overflows into local
2170 * DMA zone, if any--but risks exhausting DMA zone.
2171 */
2172static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
2173{
2174        int j;
2175        struct zonelist *zonelist;
2176
2177        zonelist = &pgdat->node_zonelists[0];
2178        for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
2179                ;
2180        j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2181                                                        MAX_NR_ZONES - 1);
2182        zonelist->_zonerefs[j].zone = NULL;
2183        zonelist->_zonerefs[j].zone_idx = 0;
2184}
2185
2186/*
2187 * Build gfp_thisnode zonelists
2188 */
2189static void build_thisnode_zonelists(pg_data_t *pgdat)
2190{
2191        int j;
2192        struct zonelist *zonelist;
2193
2194        zonelist = &pgdat->node_zonelists[1];
2195        j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
2196        zonelist->_zonerefs[j].zone = NULL;
2197        zonelist->_zonerefs[j].zone_idx = 0;
2198}
2199
2200/*
2201 * Build zonelists ordered by zone and nodes within zones.
2202 * This results in conserving DMA zone[s] until all Normal memory is
2203 * exhausted, but results in overflowing to remote node while memory
2204 * may still exist in local DMA zone.
2205 */
2206static int node_order[MAX_NUMNODES];
2207
2208static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
2209{
2210        int pos, j, node;
2211        int zone_type;          /* needs to be signed */
2212        struct zone *z;
2213        struct zonelist *zonelist;
2214
2215        zonelist = &pgdat->node_zonelists[0];
2216        pos = 0;
2217        for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
2218                for (j = 0; j < nr_nodes; j++) {
2219                        node = node_order[j];
2220                        z = &NODE_DATA(node)->node_zones[zone_type];
2221                        if (populated_zone(z)) {
2222                                zoneref_set_zone(z,
2223                                        &zonelist->_zonerefs[pos++]);
2224                                check_highest_zone(zone_type);
2225                        }
2226                }
2227        }
2228        zonelist->_zonerefs[pos].zone = NULL;
2229        zonelist->_zonerefs[pos].zone_idx = 0;
2230}
2231
2232static int default_zonelist_order(void)
2233{
2234        int nid, zone_type;
2235        unsigned long low_kmem_size,total_size;
2236        struct zone *z;
2237        int average_size;
2238        /*
2239         * ZONE_DMA and ZONE_DMA32 can be very small area in the sytem.
2240         * If they are really small and used heavily, the system can fall
2241         * into OOM very easily.
2242         * This function detect ZONE_DMA/DMA32 size and confgigures zone order.
2243         */
2244        /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
2245        low_kmem_size = 0;
2246        total_size = 0;
2247        for_each_online_node(nid) {
2248                for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
2249                        z = &NODE_DATA(nid)->node_zones[zone_type];
2250                        if (populated_zone(z)) {
2251                                if (zone_type < ZONE_NORMAL)
2252                                        low_kmem_size += z->present_pages;
2253                                total_size += z->present_pages;
2254                        }
2255                }
2256        }
2257        if (!low_kmem_size ||  /* there are no DMA area. */
2258            low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
2259                return ZONELIST_ORDER_NODE;
2260        /*
2261         * look into each node's config.
2262         * If there is a node whose DMA/DMA32 memory is very big area on
2263         * local memory, NODE_ORDER may be suitable.
2264         */
2265        average_size = total_size /
2266                                (nodes_weight(node_states[N_HIGH_MEMORY]) + 1);
2267        for_each_online_node(nid) {
2268                low_kmem_size = 0;
2269                total_size = 0;
2270                for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
2271                        z = &NODE_DATA(nid)->node_zones[zone_type];
2272                        if (populated_zone(z)) {
2273                                if (zone_type < ZONE_NORMAL)
2274                                        low_kmem_size += z->present_pages;
2275                                total_size += z->present_pages;
2276                        }
2277                }
2278                if (low_kmem_size &&
2279                    total_size > average_size && /* ignore small node */
2280                    low_kmem_size > total_size * 70/100)
2281                        return ZONELIST_ORDER_NODE;
2282        }
2283        return ZONELIST_ORDER_ZONE;
2284}
2285
2286static void set_zonelist_order(void)
2287{
2288        if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
2289                current_zonelist_order = default_zonelist_order();
2290        else
2291                current_zonelist_order = user_zonelist_order;
2292}
2293
2294static void build_zonelists(pg_data_t *pgdat)
2295{
2296        int j, node, load;
2297        enum zone_type i;
2298        nodemask_t used_mask;
2299        int local_node, prev_node;
2300        struct zonelist *zonelist;
2301        int order = current_zonelist_order;
2302
2303        /* initialize zonelists */
2304        for (i = 0; i < MAX_ZONELISTS; i++) {
2305                zonelist = pgdat->node_zonelists + i;
2306                zonelist->_zonerefs[0].zone = NULL;
2307                zonelist->_zonerefs[0].zone_idx = 0;
2308        }
2309
2310        /* NUMA-aware ordering of nodes */
2311        local_node = pgdat->node_id;
2312        load = num_online_nodes();
2313        prev_node = local_node;
2314        nodes_clear(used_mask);
2315
2316        memset(node_load, 0, sizeof(node_load));
2317        memset(node_order, 0, sizeof(node_order));
2318        j = 0;
2319
2320        while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
2321                int distance = node_distance(local_node, node);
2322
2323                /*
2324                 * If another node is sufficiently far away then it is better
2325                 * to reclaim pages in a zone before going off node.
2326                 */
2327                if (distance > RECLAIM_DISTANCE)
2328                        zone_reclaim_mode = 1;
2329
2330                /*
2331                 * We don't want to pressure a particular node.
2332                 * So adding penalty to the first node in same
2333                 * distance group to make it round-robin.
2334                 */
2335                if (distance != node_distance(local_node, prev_node))
2336                        node_load[node] = load;
2337
2338                prev_node = node;
2339                load--;
2340                if (order == ZONELIST_ORDER_NODE)
2341                        build_zonelists_in_node_order(pgdat, node);
2342                else
2343                        node_order[j++] = node; /* remember order */
2344        }
2345
2346        if (order == ZONELIST_ORDER_ZONE) {
2347                /* calculate node order -- i.e., DMA last! */
2348                build_zonelists_in_zone_order(pgdat, j);
2349        }
2350
2351        build_thisnode_zonelists(pgdat);
2352}
2353
2354/* Construct the zonelist performance cache - see further mmzone.h */
2355static void build_zonelist_cache(pg_data_t *pgdat)
2356{
2357        struct zonelist *zonelist;
2358        struct zonelist_cache *zlc;
2359        struct zoneref *z;
2360
2361        zonelist = &pgdat->node_zonelists[0];
2362        zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
2363        bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
2364        for (z = zonelist->_zonerefs; z->zone; z++)
2365                zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
2366}
2367
2368
2369#else   /* CONFIG_NUMA */
2370
2371static void set_zonelist_order(void)
2372{
2373        current_zonelist_order = ZONELIST_ORDER_ZONE;
2374}
2375
2376static void build_zonelists(pg_data_t *pgdat)
2377{
2378        int node, local_node;
2379        enum zone_type j;
2380        struct zonelist *zonelist;
2381
2382        local_node = pgdat->node_id;
2383
2384        zonelist = &pgdat->node_zonelists[0];
2385        j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
2386
2387        /*
2388         * Now we build the zonelist so that it contains the zones
2389         * of all the other nodes.
2390         * We don't want to pressure a particular node, so when
2391         * building the zones for node N, we make sure that the
2392         * zones coming right after the local ones are those from
2393         * node N+1 (modulo N)
2394         */
2395        for (node = local_node + 1; node < MAX_NUMNODES; node++) {
2396                if (!node_online(node))
2397                        continue;
2398                j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2399                                                        MAX_NR_ZONES - 1);
2400        }
2401        for (node = 0; node < local_node; node++) {
2402                if (!node_online(node))
2403                        continue;
2404                j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2405                                                        MAX_NR_ZONES - 1);
2406        }
2407
2408        zonelist->_zonerefs[j].zone = NULL;
2409        zonelist->_zonerefs[j].zone_idx = 0;
2410}
2411
2412/* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
2413static void build_zonelist_cache(pg_data_t *pgdat)
2414{
2415        pgdat->node_zonelists[0].zlcache_ptr = NULL;
2416}
2417
2418#endif  /* CONFIG_NUMA */
2419
2420/* return values int ....just for stop_machine() */
2421static int __build_all_zonelists(void *dummy)
2422{
2423        int nid;
2424
2425        for_each_online_node(nid) {
2426                pg_data_t *pgdat = NODE_DATA(nid);
2427
2428                build_zonelists(pgdat);
2429                build_zonelist_cache(pgdat);
2430        }
2431        return 0;
2432}
2433
2434void build_all_zonelists(void)
2435{
2436        set_zonelist_order();
2437
2438        if (system_state == SYSTEM_BOOTING) {
2439                __build_all_zonelists(NULL);
2440                mminit_verify_zonelist();
2441                cpuset_init_current_mems_allowed();
2442        } else {
2443                /* we have to stop all cpus to guarantee there is no user
2444                   of zonelist */
2445                stop_machine(__build_all_zonelists, NULL, NULL);
2446                /* cpuset refresh routine should be here */
2447        }
2448        vm_total_pages = nr_free_pagecache_pages();
2449        /*
2450         * Disable grouping by mobility if the number of pages in the
2451         * system is too low to allow the mechanism to work. It would be
2452         * more accurate, but expensive to check per-zone. This check is
2453         * made on memory-hotadd so a system can start with mobility
2454         * disabled and enable it later
2455         */
2456        if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
2457                page_group_by_mobility_disabled = 1;
2458        else
2459                page_group_by_mobility_disabled = 0;
2460
2461        printk("Built %i zonelists in %s order, mobility grouping %s.  "
2462                "Total pages: %ld\n",
2463                        num_online_nodes(),
2464                        zonelist_order_name[current_zonelist_order],
2465                        page_group_by_mobility_disabled ? "off" : "on",
2466                        vm_total_pages);
2467#ifdef CONFIG_NUMA
2468        printk("Policy zone: %s\n", zone_names[policy_zone]);
2469#endif
2470}
2471
2472/*
2473 * Helper functions to size the waitqueue hash table.
2474 * Essentially these want to choose hash table sizes sufficiently
2475 * large so that collisions trying to wait on pages are rare.
2476 * But in fact, the number of active page waitqueues on typical
2477 * systems is ridiculously low, less than 200. So this is even
2478 * conservative, even though it seems large.
2479 *
2480 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
2481 * waitqueues, i.e. the size of the waitq table given the number of pages.
2482 */
2483#define PAGES_PER_WAITQUEUE     256
2484
2485#ifndef CONFIG_MEMORY_HOTPLUG
2486static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
2487{
2488        unsigned long size = 1;
2489
2490        pages /= PAGES_PER_WAITQUEUE;
2491
2492        while (size < pages)
2493                size <<= 1;
2494
2495        /*
2496         * Once we have dozens or even hundreds of threads sleeping
2497         * on IO we've got bigger problems than wait queue collision.
2498         * Limit the size of the wait table to a reasonable size.
2499         */
2500        size = min(size, 4096UL);
2501
2502        return max(size, 4UL);
2503}
2504#else
2505/*
2506 * A zone's size might be changed by hot-add, so it is not possible to determine
2507 * a suitable size for its wait_table.  So we use the maximum size now.
2508 *
2509 * The max wait table size = 4096 x sizeof(wait_queue_head_t).   ie:
2510 *
2511 *    i386 (preemption config)    : 4096 x 16 = 64Kbyte.
2512 *    ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
2513 *    ia64, x86-64 (preemption)   : 4096 x 24 = 96Kbyte.
2514 *
2515 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
2516 * or more by the traditional way. (See above).  It equals:
2517 *
2518 *    i386, x86-64, powerpc(4K page size) : =  ( 2G + 1M)byte.
2519 *    ia64(16K page size)                 : =  ( 8G + 4M)byte.
2520 *    powerpc (64K page size)             : =  (32G +16M)byte.
2521 */
2522static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
2523{
2524        return 4096UL;
2525}
2526#endif
2527
2528/*
2529 * This is an integer logarithm so that shifts can be used later
2530 * to extract the more random high bits from the multiplicative
2531 * hash function before the remainder is taken.
2532 */
2533static inline unsigned long wait_table_bits(unsigned long size)
2534{
2535        return ffz(~size);
2536}
2537
2538#define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
2539
2540/*
2541 * Mark a number of pageblocks as MIGRATE_RESERVE. The number
2542 * of blocks reserved is based on zone->pages_min. The memory within the
2543 * reserve will tend to store contiguous free pages. Setting min_free_kbytes
2544 * higher will lead to a bigger reserve which will get freed as contiguous
2545 * blocks as reclaim kicks in
2546 */
2547static void setup_zone_migrate_reserve(struct zone *zone)
2548{
2549        unsigned long start_pfn, pfn, end_pfn;
2550        struct page *page;
2551        unsigned long reserve, block_migratetype;
2552
2553        /* Get the start pfn, end pfn and the number of blocks to reserve */
2554        start_pfn = zone->zone_start_pfn;
2555        end_pfn = start_pfn + zone->spanned_pages;
2556        reserve = roundup(zone->pages_min, pageblock_nr_pages) >>
2557                                                        pageblock_order;
2558
2559        for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
2560                if (!pfn_valid(pfn))
2561                        continue;
2562                page = pfn_to_page(pfn);
2563
2564                /* Watch out for overlapping nodes */
2565                if (page_to_nid(page) != zone_to_nid(zone))
2566                        continue;
2567
2568                /* Blocks with reserved pages will never free, skip them. */
2569                if (PageReserved(page))
2570                        continue;
2571
2572                block_migratetype = get_pageblock_migratetype(page);
2573
2574                /* If this block is reserved, account for it */
2575                if (reserve > 0 && block_migratetype == MIGRATE_RESERVE) {
2576                        reserve--;
2577                        continue;
2578                }
2579
2580                /* Suitable for reserving if this block is movable */
2581                if (reserve > 0 && block_migratetype == MIGRATE_MOVABLE) {
2582                        set_pageblock_migratetype(page, MIGRATE_RESERVE);
2583                        move_freepages_block(zone, page, MIGRATE_RESERVE);
2584                        reserve--;
2585                        continue;
2586                }
2587
2588                /*
2589                 * If the reserve is met and this is a previous reserved block,
2590                 * take it back
2591                 */
2592                if (block_migratetype == MIGRATE_RESERVE) {
2593                        set_pageblock_migratetype(page, MIGRATE_MOVABLE);
2594                        move_freepages_block(zone, page, MIGRATE_MOVABLE);
2595                }
2596        }
2597}
2598
2599/*
2600 * Initially all pages are reserved - free ones are freed
2601 * up by free_all_bootmem() once the early boot process is
2602 * done. Non-atomic initialization, single-pass.
2603 */
2604void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
2605                unsigned long start_pfn, enum memmap_context context)
2606{
2607        struct page *page;
2608        unsigned long end_pfn = start_pfn + size;
2609        unsigned long pfn;
2610        struct zone *z;
2611
2612        z = &NODE_DATA(nid)->node_zones[zone];
2613        for (pfn = start_pfn; pfn < end_pfn; pfn++) {
2614                /*
2615                 * There can be holes in boot-time mem_map[]s
2616                 * handed to this function.  They do not
2617                 * exist on hotplugged memory.
2618                 */
2619                if (context == MEMMAP_EARLY) {
2620                        if (!early_pfn_valid(pfn))
2621                                continue;
2622                        if (!early_pfn_in_nid(pfn, nid))
2623                                continue;
2624                }
2625                page = pfn_to_page(pfn);
2626                set_page_links(page, zone, nid, pfn);
2627                mminit_verify_page_links(page, zone, nid, pfn);
2628                init_page_count(page);
2629                reset_page_mapcount(page);
2630                SetPageReserved(page);
2631                /*
2632                 * Mark the block movable so that blocks are reserved for
2633                 * movable at startup. This will force kernel allocations
2634                 * to reserve their blocks rather than leaking throughout
2635                 * the address space during boot when many long-lived
2636                 * kernel allocations are made. Later some blocks near
2637                 * the start are marked MIGRATE_RESERVE by
2638                 * setup_zone_migrate_reserve()
2639                 *
2640                 * bitmap is created for zone's valid pfn range. but memmap
2641                 * can be created for invalid pages (for alignment)
2642                 * check here not to call set_pageblock_migratetype() against
2643                 * pfn out of zone.
2644                 */
2645                if ((z->zone_start_pfn <= pfn)
2646                    && (pfn < z->zone_start_pfn + z->spanned_pages)
2647                    && !(pfn & (pageblock_nr_pages - 1)))
2648                        set_pageblock_migratetype(page, MIGRATE_MOVABLE);
2649
2650                INIT_LIST_HEAD(&page->lru);
2651#ifdef WANT_PAGE_VIRTUAL
2652                /* The shift won't overflow because ZONE_NORMAL is below 4G. */
2653                if (!is_highmem_idx(zone))
2654                        set_page_address(page, __va(pfn << PAGE_SHIFT));
2655#endif
2656        }
2657}
2658
2659static void __meminit zone_init_free_lists(struct zone *zone)
2660{
2661        int order, t;
2662        for_each_migratetype_order(order, t) {
2663                INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
2664                zone->free_area[order].nr_free = 0;
2665        }
2666}
2667
2668#ifndef __HAVE_ARCH_MEMMAP_INIT
2669#define memmap_init(size, nid, zone, start_pfn) \
2670        memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
2671#endif
2672
2673static int zone_batchsize(struct zone *zone)
2674{
2675        int batch;
2676
2677        /*
2678         * The per-cpu-pages pools are set to around 1000th of the
2679         * size of the zone.  But no more than 1/2 of a meg.
2680         *
2681         * OK, so we don't know how big the cache is.  So guess.
2682         */
2683        batch = zone->present_pages / 1024;
2684        if (batch * PAGE_SIZE > 512 * 1024)
2685                batch = (512 * 1024) / PAGE_SIZE;
2686        batch /= 4;             /* We effectively *= 4 below */
2687        if (batch < 1)
2688                batch = 1;
2689
2690        /*
2691         * Clamp the batch to a 2^n - 1 value. Having a power
2692         * of 2 value was found to be more likely to have
2693         * suboptimal cache aliasing properties in some cases.
2694         *
2695         * For example if 2 tasks are alternately allocating
2696         * batches of pages, one task can end up with a lot
2697         * of pages of one half of the possible page colors
2698         * and the other with pages of the other colors.
2699         */
2700        batch = (1 << (fls(batch + batch/2)-1)) - 1;
2701
2702        return batch;
2703}
2704
2705static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
2706{
2707        struct per_cpu_pages *pcp;
2708
2709        memset(p, 0, sizeof(*p));
2710
2711        pcp = &p->pcp;
2712        pcp->count = 0;
2713        pcp->high = 6 * batch;
2714        pcp->batch = max(1UL, 1 * batch);
2715        INIT_LIST_HEAD(&pcp->list);
2716}
2717
2718/*
2719 * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
2720 * to the value high for the pageset p.
2721 */
2722
2723static void setup_pagelist_highmark(struct per_cpu_pageset *p,
2724                                unsigned long high)
2725{
2726        struct per_cpu_pages *pcp;
2727
2728        pcp = &p->pcp;
2729        pcp->high = high;
2730        pcp->batch = max(1UL, high/4);
2731        if ((high/4) > (PAGE_SHIFT * 8))
2732                pcp->batch = PAGE_SHIFT * 8;
2733}
2734
2735
2736#ifdef CONFIG_NUMA
2737/*
2738 * Boot pageset table. One per cpu which is going to be used for all
2739 * zones and all nodes. The parameters will be set in such a way
2740 * that an item put on a list will immediately be handed over to
2741 * the buddy list. This is safe since pageset manipulation is done
2742 * with interrupts disabled.
2743 *
2744 * Some NUMA counter updates may also be caught by the boot pagesets.
2745 *
2746 * The boot_pagesets must be kept even after bootup is complete for
2747 * unused processors and/or zones. They do play a role for bootstrapping
2748 * hotplugged processors.
2749 *
2750 * zoneinfo_show() and maybe other functions do
2751 * not check if the processor is online before following the pageset pointer.
2752 * Other parts of the kernel may not check if the zone is available.
2753 */
2754static struct per_cpu_pageset boot_pageset[NR_CPUS];
2755
2756/*
2757 * Dynamically allocate memory for the
2758 * per cpu pageset array in struct zone.
2759 */
2760static int __cpuinit process_zones(int cpu)
2761{
2762        struct zone *zone, *dzone;
2763        int node = cpu_to_node(cpu);
2764
2765        node_set_state(node, N_CPU);    /* this node has a cpu */
2766
2767        for_each_zone(zone) {
2768
2769                if (!populated_zone(zone))
2770                        continue;
2771
2772                zone_pcp(zone, cpu) = kmalloc_node(sizeof(struct per_cpu_pageset),
2773                                         GFP_KERNEL, node);
2774                if (!zone_pcp(zone, cpu))
2775                        goto bad;
2776
2777                setup_pageset(zone_pcp(zone, cpu), zone_batchsize(zone));
2778
2779                if (percpu_pagelist_fraction)
2780                        setup_pagelist_highmark(zone_pcp(zone, cpu),
2781                                (zone->present_pages / percpu_pagelist_fraction));
2782        }
2783
2784        return 0;
2785bad:
2786        for_each_zone(dzone) {
2787                if (!populated_zone(dzone))
2788                        continue;
2789                if (dzone == zone)
2790                        break;
2791                kfree(zone_pcp(dzone, cpu));
2792                zone_pcp(dzone, cpu) = NULL;
2793        }
2794        return -ENOMEM;
2795}
2796
2797static inline void free_zone_pagesets(int cpu)
2798{
2799        struct zone *zone;
2800
2801        for_each_zone(zone) {
2802                struct per_cpu_pageset *pset = zone_pcp(zone, cpu);
2803
2804                /* Free per_cpu_pageset if it is slab allocated */
2805                if (pset != &boot_pageset[cpu])
2806                        kfree(pset);
2807                zone_pcp(zone, cpu) = NULL;
2808        }
2809}
2810
2811static int __cpuinit pageset_cpuup_callback(struct notifier_block *nfb,
2812                unsigned long action,
2813                void *hcpu)
2814{
2815        int cpu = (long)hcpu;
2816        int ret = NOTIFY_OK;
2817
2818        switch (action) {
2819        case CPU_UP_PREPARE:
2820        case CPU_UP_PREPARE_FROZEN:
2821                if (process_zones(cpu))
2822                        ret = NOTIFY_BAD;
2823                break;
2824        case CPU_UP_CANCELED:
2825        case CPU_UP_CANCELED_FROZEN:
2826        case CPU_DEAD:
2827        case CPU_DEAD_FROZEN:
2828                free_zone_pagesets(cpu);
2829                break;
2830        default:
2831                break;
2832        }
2833        return ret;
2834}
2835
2836static struct notifier_block __cpuinitdata pageset_notifier =
2837        { &pageset_cpuup_callback, NULL, 0 };
2838
2839void __init setup_per_cpu_pageset(void)
2840{
2841        int err;
2842
2843        /* Initialize per_cpu_pageset for cpu 0.
2844         * A cpuup callback will do this for every cpu
2845         * as it comes online
2846         */
2847        err = process_zones(smp_processor_id());
2848        BUG_ON(err);
2849        register_cpu_notifier(&pageset_notifier);
2850}
2851
2852#endif
2853
2854static noinline __init_refok
2855int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
2856{
2857        int i;
2858        struct pglist_data *pgdat = zone->zone_pgdat;
2859        size_t alloc_size;
2860
2861        /*
2862         * The per-page waitqueue mechanism uses hashed waitqueues
2863         * per zone.
2864         */
2865        zone->wait_table_hash_nr_entries =
2866                 wait_table_hash_nr_entries(zone_size_pages);
2867        zone->wait_table_bits =
2868                wait_table_bits(zone->wait_table_hash_nr_entries);
2869        alloc_size = zone->wait_table_hash_nr_entries
2870                                        * sizeof(wait_queue_head_t);
2871
2872        if (!slab_is_available()) {
2873                zone->wait_table = (wait_queue_head_t *)
2874                        alloc_bootmem_node(pgdat, alloc_size);
2875        } else {
2876                /*
2877                 * This case means that a zone whose size was 0 gets new memory
2878                 * via memory hot-add.
2879                 * But it may be the case that a new node was hot-added.  In
2880                 * this case vmalloc() will not be able to use this new node's
2881                 * memory - this wait_table must be initialized to use this new
2882                 * node itself as well.
2883                 * To use this new node's memory, further consideration will be
2884                 * necessary.
2885                 */
2886                zone->wait_table = vmalloc(alloc_size);
2887        }
2888        if (!zone->wait_table)
2889                return -ENOMEM;
2890
2891        for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
2892                init_waitqueue_head(zone->wait_table + i);
2893
2894        return 0;
2895}
2896
2897static __meminit void zone_pcp_init(struct zone *zone)
2898{
2899        int cpu;
2900        unsigned long batch = zone_batchsize(zone);
2901
2902        for (cpu = 0; cpu < NR_CPUS; cpu++) {
2903#ifdef CONFIG_NUMA
2904                /* Early boot. Slab allocator not functional yet */
2905                zone_pcp(zone, cpu) = &boot_pageset[cpu];
2906                setup_pageset(&boot_pageset[cpu],0);
2907#else
2908                setup_pageset(zone_pcp(zone,cpu), batch);
2909#endif
2910        }
2911        if (zone->present_pages)
2912                printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%lu\n",
2913                        zone->name, zone->present_pages, batch);
2914}
2915
2916__meminit int init_currently_empty_zone(struct zone *zone,
2917                                        unsigned long zone_start_pfn,
2918                                        unsigned long size,
2919                                        enum memmap_context context)
2920{
2921        struct pglist_data *pgdat = zone->zone_pgdat;
2922        int ret;
2923        ret = zone_wait_table_init(zone, size);
2924        if (ret)
2925                return ret;
2926        pgdat->nr_zones = zone_idx(zone) + 1;
2927
2928        zone->zone_start_pfn = zone_start_pfn;
2929
2930        mminit_dprintk(MMINIT_TRACE, "memmap_init",
2931                        "Initialising map node %d zone %lu pfns %lu -> %lu\n",
2932                        pgdat->node_id,
2933                        (unsigned long)zone_idx(zone),
2934                        zone_start_pfn, (zone_start_pfn + size));
2935
2936        zone_init_free_lists(zone);
2937
2938        return 0;
2939}
2940
2941#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
2942/*
2943 * Basic iterator support. Return the first range of PFNs for a node
2944 * Note: nid == MAX_NUMNODES returns first region regardless of node
2945 */
2946static int __meminit first_active_region_index_in_nid(int nid)
2947{
2948        int i;
2949
2950        for (i = 0; i < nr_nodemap_entries; i++)
2951                if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
2952                        return i;
2953
2954        return -1;
2955}
2956
2957/*
2958 * Basic iterator support. Return the next active range of PFNs for a node
2959 * Note: nid == MAX_NUMNODES returns next region regardless of node
2960 */
2961static int __meminit next_active_region_index_in_nid(int index, int nid)
2962{
2963        for (index = index + 1; index < nr_nodemap_entries; index++)
2964                if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
2965                        return index;
2966
2967        return -1;
2968}
2969
2970#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
2971/*
2972 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
2973 * Architectures may implement their own version but if add_active_range()
2974 * was used and there are no special requirements, this is a convenient
2975 * alternative
2976 */
2977int __meminit early_pfn_to_nid(unsigned long pfn)
2978{
2979        int i;
2980
2981        for (i = 0; i < nr_nodemap_entries; i++) {
2982                unsigned long start_pfn = early_node_map[i].start_pfn;
2983                unsigned long end_pfn = early_node_map[i].end_pfn;
2984
2985                if (start_pfn <= pfn && pfn < end_pfn)
2986                        return early_node_map[i].nid;
2987        }
2988
2989        return 0;
2990}
2991#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
2992
2993/* Basic iterator support to walk early_node_map[] */
2994#define for_each_active_range_index_in_nid(i, nid) \
2995        for (i = first_active_region_index_in_nid(nid); i != -1; \
2996                                i = next_active_region_index_in_nid(i, nid))
2997
2998/**
2999 * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
3000 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
3001 * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
3002 *
3003 * If an architecture guarantees that all ranges registered with
3004 * add_active_ranges() contain no holes and may be freed, this
3005 * this function may be used instead of calling free_bootmem() manually.
3006 */
3007void __init free_bootmem_with_active_regions(int nid,
3008                                                unsigned long max_low_pfn)
3009{
3010        int i;
3011
3012        for_each_active_range_index_in_nid(i, nid) {
3013                unsigned long size_pages = 0;
3014                unsigned long end_pfn = early_node_map[i].end_pfn;
3015
3016                if (early_node_map[i].start_pfn >= max_low_pfn)
3017                        continue;
3018
3019                if (end_pfn > max_low_pfn)
3020                        end_pfn = max_low_pfn;
3021
3022                size_pages = end_pfn - early_node_map[i].start_pfn;
3023                free_bootmem_node(NODE_DATA(early_node_map[i].nid),
3024                                PFN_PHYS(early_node_map[i].start_pfn),
3025                                size_pages << PAGE_SHIFT);
3026        }
3027}
3028
3029void __init work_with_active_regions(int nid, work_fn_t work_fn, void *data)
3030{
3031        int i;
3032        int ret;
3033
3034        for_each_active_range_index_in_nid(i, nid) {
3035                ret = work_fn(early_node_map[i].start_pfn,
3036                              early_node_map[i].end_pfn, data);
3037                if (ret)
3038                        break;
3039        }
3040}
3041/**
3042 * sparse_memory_present_with_active_regions - Call memory_present for each active range
3043 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
3044 *
3045 * If an architecture guarantees that all ranges registered with
3046 * add_active_ranges() contain no holes and may be freed, this
3047 * function may be used instead of calling memory_present() manually.
3048 */
3049void __init sparse_memory_present_with_active_regions(int nid)
3050{
3051        int i;
3052
3053        for_each_active_range_index_in_nid(i, nid)
3054                memory_present(early_node_map[i].nid,
3055                                early_node_map[i].start_pfn,
3056                                early_node_map[i].end_pfn);
3057}
3058
3059/**
3060 * push_node_boundaries - Push node boundaries to at least the requested boundary
3061 * @nid: The nid of the node to push the boundary for
3062 * @start_pfn: The start pfn of the node
3063 * @end_pfn: The end pfn of the node
3064 *
3065 * In reserve-based hot-add, mem_map is allocated that is unused until hotadd
3066 * time. Specifically, on x86_64, SRAT will report ranges that can potentially
3067 * be hotplugged even though no physical memory exists. This function allows
3068 * an arch to push out the node boundaries so mem_map is allocated that can
3069 * be used later.
3070 */
3071#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
3072void __init push_node_boundaries(unsigned int nid,
3073                unsigned long start_pfn, unsigned long end_pfn)
3074{
3075        mminit_dprintk(MMINIT_TRACE, "zoneboundary",
3076                        "Entering push_node_boundaries(%u, %lu, %lu)\n",
3077                        nid, start_pfn, end_pfn);
3078
3079        /* Initialise the boundary for this node if necessary */
3080        if (node_boundary_end_pfn[nid] == 0)
3081                node_boundary_start_pfn[nid] = -1UL;
3082
3083        /* Update the boundaries */
3084        if (node_boundary_start_pfn[nid] > start_pfn)
3085                node_boundary_start_pfn[nid] = start_pfn;
3086        if (node_boundary_end_pfn[nid] < end_pfn)
3087                node_boundary_end_pfn[nid] = end_pfn;
3088}
3089
3090/* If necessary, push the node boundary out for reserve hotadd */
3091static void __meminit account_node_boundary(unsigned int nid,
3092                unsigned long *start_pfn, unsigned long *end_pfn)
3093{
3094        mminit_dprintk(MMINIT_TRACE, "zoneboundary",
3095                        "Entering account_node_boundary(%u, %lu, %lu)\n",
3096                        nid, *start_pfn, *end_pfn);
3097
3098        /* Return if boundary information has not been provided */
3099        if (node_boundary_end_pfn[nid] == 0)
3100                return;
3101
3102        /* Check the boundaries and update if necessary */
3103        if (node_boundary_start_pfn[nid] < *start_pfn)
3104                *start_pfn = node_boundary_start_pfn[nid];
3105        if (node_boundary_end_pfn[nid] > *end_pfn)
3106                *end_pfn = node_boundary_end_pfn[nid];
3107}
3108#else
3109void __init push_node_boundaries(unsigned int nid,
3110                unsigned long start_pfn, unsigned long end_pfn) {}
3111
3112static void __meminit account_node_boundary(unsigned int nid,
3113                unsigned long *start_pfn, unsigned long *end_pfn) {}
3114#endif
3115
3116
3117/**
3118 * get_pfn_range_for_nid - Return the start and end page frames for a node
3119 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
3120 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
3121 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
3122 *
3123 * It returns the start and end page frame of a node based on information
3124 * provided by an arch calling add_active_range(). If called for a node
3125 * with no available memory, a warning is printed and the start and end
3126 * PFNs will be 0.
3127 */
3128void __meminit get_pfn_range_for_nid(unsigned int nid,
3129                        unsigned long *start_pfn, unsigned long *end_pfn)
3130{
3131        int i;
3132        *start_pfn = -1UL;
3133        *end_pfn = 0;
3134
3135        for_each_active_range_index_in_nid(i, nid) {
3136                *start_pfn = min(*start_pfn, early_node_map[i].start_pfn);
3137                *end_pfn = max(*end_pfn, early_node_map[i].end_pfn);
3138        }
3139
3140        if (*start_pfn == -1UL)
3141                *start_pfn = 0;
3142
3143        /* Push the node boundaries out if requested */
3144        account_node_boundary(nid, start_pfn, end_pfn);
3145}
3146
3147/*
3148 * This finds a zone that can be used for ZONE_MOVABLE pages. The
3149 * assumption is made that zones within a node are ordered in monotonic
3150 * increasing memory addresses so that the "highest" populated zone is used
3151 */
3152static void __init find_usable_zone_for_movable(void)
3153{
3154        int zone_index;
3155        for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
3156                if (zone_index == ZONE_MOVABLE)
3157                        continue;
3158
3159                if (arch_zone_highest_possible_pfn[zone_index] >
3160                                arch_zone_lowest_possible_pfn[zone_index])
3161                        break;
3162        }
3163
3164        VM_BUG_ON(zone_index == -1);
3165        movable_zone = zone_index;
3166}
3167
3168/*
3169 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
3170 * because it is sized independant of architecture. Unlike the other zones,
3171 * the starting point for ZONE_MOVABLE is not fixed. It may be different
3172 * in each node depending on the size of each node and how evenly kernelcore
3173 * is distributed. This helper function adjusts the zone ranges
3174 * provided by the architecture for a given node by using the end of the
3175 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
3176 * zones within a node are in order of monotonic increases memory addresses
3177 */
3178static void __meminit adjust_zone_range_for_zone_movable(int nid,
3179                                        unsigned long zone_type,
3180                                        unsigned long node_start_pfn,
3181                                        unsigned long node_end_pfn,
3182                                        unsigned long *zone_start_pfn,
3183                                        unsigned long *zone_end_pfn)
3184{
3185        /* Only adjust if ZONE_MOVABLE is on this node */
3186        if (zone_movable_pfn[nid]) {
3187                /* Size ZONE_MOVABLE */
3188                if (zone_type == ZONE_MOVABLE) {
3189                        *zone_start_pfn = zone_movable_pfn[nid];
3190                        *zone_end_pfn = min(node_end_pfn,
3191                                arch_zone_highest_possible_pfn[movable_zone]);
3192
3193                /* Adjust for ZONE_MOVABLE starting within this range */
3194                } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
3195                                *zone_end_pfn > zone_movable_pfn[nid]) {
3196                        *zone_end_pfn = zone_movable_pfn[nid];
3197
3198                /* Check if this whole range is within ZONE_MOVABLE */
3199                } else if (*zone_start_pfn >= zone_movable_pfn[nid])
3200                        *zone_start_pfn = *zone_end_pfn;
3201        }
3202}
3203
3204/*
3205 * Return the number of pages a zone spans in a node, including holes
3206 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
3207 */
3208static unsigned long __meminit zone_spanned_pages_in_node(int nid,
3209                                        unsigned long zone_type,
3210                                        unsigned long *ignored)
3211{
3212        unsigned long node_start_pfn, node_end_pfn;
3213        unsigned long zone_start_pfn, zone_end_pfn;
3214
3215        /* Get the start and end of the node and zone */
3216        get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
3217        zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
3218        zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
3219        adjust_zone_range_for_zone_movable(nid, zone_type,
3220                                node_start_pfn, node_end_pfn,
3221                                &zone_start_pfn, &zone_end_pfn);
3222
3223        /* Check that this node has pages within the zone's required range */
3224        if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
3225                return 0;
3226
3227        /* Move the zone boundaries inside the node if necessary */
3228        zone_end_pfn = min(zone_end_pfn, node_end_pfn);
3229        zone_start_pfn = max(zone_start_pfn, node_start_pfn);
3230
3231        /* Return the spanned pages */
3232        return zone_end_pfn - zone_start_pfn;
3233}
3234
3235/*
3236 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
3237 * then all holes in the requested range will be accounted for.
3238 */
3239static unsigned long __meminit __absent_pages_in_range(int nid,
3240                                unsigned long range_start_pfn,
3241                                unsigned long range_end_pfn)
3242{
3243        int i = 0;
3244        unsigned long prev_end_pfn = 0, hole_pages = 0;
3245        unsigned long start_pfn;
3246
3247        /* Find the end_pfn of the first active range of pfns in the node */
3248        i = first_active_region_index_in_nid(nid);
3249        if (i == -1)
3250                return 0;
3251
3252        prev_end_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
3253
3254        /* Account for ranges before physical memory on this node */
3255        if (early_node_map[i].start_pfn > range_start_pfn)
3256                hole_pages = prev_end_pfn - range_start_pfn;
3257
3258        /* Find all holes for the zone within the node */
3259        for (; i != -1; i = next_active_region_index_in_nid(i, nid)) {
3260
3261                /* No need to continue if prev_end_pfn is outside the zone */
3262                if (prev_end_pfn >= range_end_pfn)
3263                        break;
3264
3265                /* Make sure the end of the zone is not within the hole */
3266                start_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
3267                prev_end_pfn = max(prev_end_pfn, range_start_pfn);
3268
3269                /* Update the hole size cound and move on */
3270                if (start_pfn > range_start_pfn) {
3271                        BUG_ON(prev_end_pfn > start_pfn);
3272                        hole_pages += start_pfn - prev_end_pfn;
3273                }
3274                prev_end_pfn = early_node_map[i].end_pfn;
3275        }
3276
3277        /* Account for ranges past physical memory on this node */
3278        if (range_end_pfn > prev_end_pfn)
3279                hole_pages += range_end_pfn -
3280                                max(range_start_pfn, prev_end_pfn);
3281
3282        return hole_pages;
3283}
3284
3285/**
3286 * absent_pages_in_range - Return number of page frames in holes within a range
3287 * @start_pfn: The start PFN to start searching for holes
3288 * @end_pfn: The end PFN to stop searching for holes
3289 *
3290 * It returns the number of pages frames in memory holes within a range.
3291 */
3292unsigned long __init absent_pages_in_range(unsigned long start_pfn,
3293                                                        unsigned long end_pfn)
3294{
3295        return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
3296}
3297
3298/* Return the number of page frames in holes in a zone on a node */
3299static unsigned long __meminit zone_absent_pages_in_node(int nid,
3300                                        unsigned long zone_type,
3301                                        unsigned long *ignored)
3302{
3303        unsigned long node_start_pfn, node_end_pfn;
3304        unsigned long zone_start_pfn, zone_end_pfn;
3305
3306        get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
3307        zone_start_pfn = max(arch_zone_lowest_possible_pfn[zone_type],
3308                                                        node_start_pfn);
3309        zone_end_pfn = min(arch_zone_highest_possible_pfn[zone_type],
3310                                                        node_end_pfn);
3311
3312        adjust_zone_range_for_zone_movable(nid, zone_type,
3313                        node_start_pfn, node_end_pfn,
3314                        &zone_start_pfn, &zone_end_pfn);
3315        return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
3316}
3317
3318#else
3319static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
3320                                        unsigned long zone_type,
3321                                        unsigned long *zones_size)
3322{
3323        return zones_size[zone_type];
3324}
3325
3326static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
3327                                                unsigned long zone_type,
3328                                                unsigned long *zholes_size)
3329{
3330        if (!zholes_size)
3331                return 0;
3332
3333        return zholes_size[zone_type];
3334}
3335
3336#endif
3337
3338static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
3339                unsigned long *zones_size, unsigned long *zholes_size)
3340{
3341        unsigned long realtotalpages, totalpages = 0;
3342        enum zone_type i;
3343
3344        for (i = 0; i < MAX_NR_ZONES; i++)
3345                totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
3346                                                                zones_size);
3347        pgdat->node_spanned_pages = totalpages;
3348
3349        realtotalpages = totalpages;
3350        for (i = 0; i < MAX_NR_ZONES; i++)
3351                realtotalpages -=
3352                        zone_absent_pages_in_node(pgdat->node_id, i,
3353                                                                zholes_size);
3354        pgdat->node_present_pages = realtotalpages;
3355        printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
3356                                                        realtotalpages);
3357}
3358
3359#ifndef CONFIG_SPARSEMEM
3360/*
3361 * Calculate the size of the zone->blockflags rounded to an unsigned long
3362 * Start by making sure zonesize is a multiple of pageblock_order by rounding
3363 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
3364 * round what is now in bits to nearest long in bits, then return it in
3365 * bytes.
3366 */
3367static unsigned long __init usemap_size(unsigned long zonesize)
3368{
3369        unsigned long usemapsize;
3370
3371        usemapsize = roundup(zonesize, pageblock_nr_pages);
3372        usemapsize = usemapsize >> pageblock_order;
3373        usemapsize *= NR_PAGEBLOCK_BITS;
3374        usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
3375
3376        return usemapsize / 8;
3377}
3378
3379static void __init setup_usemap(struct pglist_data *pgdat,
3380                                struct zone *zone, unsigned long zonesize)
3381{
3382        unsigned long usemapsize = usemap_size(zonesize);
3383        zone->pageblock_flags = NULL;
3384        if (usemapsize) {
3385                zone->pageblock_flags = alloc_bootmem_node(pgdat, usemapsize);
3386                memset(zone->pageblock_flags, 0, usemapsize);
3387        }
3388}
3389#else
3390static void inline setup_usemap(struct pglist_data *pgdat,
3391                                struct zone *zone, unsigned long zonesize) {}
3392#endif /* CONFIG_SPARSEMEM */
3393
3394#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
3395
3396/* Return a sensible default order for the pageblock size. */
3397static inline int pageblock_default_order(void)
3398{
3399        if (HPAGE_SHIFT > PAGE_SHIFT)
3400                return HUGETLB_PAGE_ORDER;
3401
3402        return MAX_ORDER-1;
3403}
3404
3405/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
3406static inline void __init set_pageblock_order(unsigned int order)
3407{
3408        /* Check that pageblock_nr_pages has not already been setup */
3409        if (pageblock_order)
3410                return;
3411
3412        /*
3413         * Assume the largest contiguous order of interest is a huge page.
3414         * This value may be variable depending on boot parameters on IA64
3415         */
3416        pageblock_order = order;
3417}
3418#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
3419
3420/*
3421 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
3422 * and pageblock_default_order() are unused as pageblock_order is set
3423 * at compile-time. See include/linux/pageblock-flags.h for the values of
3424 * pageblock_order based on the kernel config
3425 */
3426static inline int pageblock_default_order(unsigned int order)
3427{
3428        return MAX_ORDER-1;
3429}
3430#define set_pageblock_order(x)  do {} while (0)
3431
3432#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
3433
3434/*
3435 * Set up the zone data structures:
3436 *   - mark all pages reserved
3437 *   - mark all memory queues empty
3438 *   - clear the memory bitmaps
3439 */
3440static void __paginginit free_area_init_core(struct pglist_data *pgdat,
3441                unsigned long *zones_size, unsigned long *zholes_size)
3442{
3443        enum zone_type j;
3444        int nid = pgdat->node_id;
3445        unsigned long zone_start_pfn = pgdat->node_start_pfn;
3446        int ret;
3447
3448        pgdat_resize_init(pgdat);
3449        pgdat->nr_zones = 0;
3450        init_waitqueue_head(&pgdat->kswapd_wait);
3451        pgdat->kswapd_max_order = 0;
3452        pgdat_page_cgroup_init(pgdat);
3453        
3454        for (j = 0; j < MAX_NR_ZONES; j++) {
3455                struct zone *zone = pgdat->node_zones + j;
3456                unsigned long size, realsize, memmap_pages;
3457                enum lru_list l;
3458
3459                size = zone_spanned_pages_in_node(nid, j, zones_size);
3460                realsize = size - zone_absent_pages_in_node(nid, j,
3461                                                                zholes_size);
3462
3463                /*
3464                 * Adjust realsize so that it accounts for how much memory
3465                 * is used by this zone for memmap. This affects the watermark
3466                 * and per-cpu initialisations
3467                 */
3468                memmap_pages =
3469                        PAGE_ALIGN(size * sizeof(struct page)) >> PAGE_SHIFT;
3470                if (realsize >= memmap_pages) {
3471                        realsize -= memmap_pages;
3472                        printk(KERN_DEBUG
3473                                "  %s zone: %lu pages used for memmap\n",
3474                                zone_names[j], memmap_pages);
3475                } else
3476                        printk(KERN_WARNING
3477                                "  %s zone: %lu pages exceeds realsize %lu\n",
3478                                zone_names[j], memmap_pages, realsize);
3479
3480                /* Account for reserved pages */
3481                if (j == 0 && realsize > dma_reserve) {
3482                        realsize -= dma_reserve;
3483                        printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
3484                                        zone_names[0], dma_reserve);
3485                }
3486
3487                if (!is_highmem_idx(j))
3488                        nr_kernel_pages += realsize;
3489                nr_all_pages += realsize;
3490
3491                zone->spanned_pages = size;
3492                zone->present_pages = realsize;
3493#ifdef CONFIG_NUMA
3494                zone->node = nid;
3495                zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
3496                                                / 100;
3497                zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
3498#endif
3499                zone->name = zone_names[j];
3500                spin_lock_init(&zone->lock);
3501                spin_lock_init(&zone->lru_lock);
3502                zone_seqlock_init(zone);
3503                zone->zone_pgdat = pgdat;
3504
3505                zone->prev_priority = DEF_PRIORITY;
3506
3507                zone_pcp_init(zone);
3508                for_each_lru(l) {
3509                        INIT_LIST_HEAD(&zone->lru[l].list);
3510                        zone->lru[l].nr_scan = 0;
3511                }
3512                zone->recent_rotated[0] = 0;
3513                zone->recent_rotated[1] = 0;
3514                zone->recent_scanned[0] = 0;
3515                zone->recent_scanned[1] = 0;
3516                zap_zone_vm_stats(zone);
3517                zone->flags = 0;
3518                if (!size)
3519                        continue;
3520
3521                set_pageblock_order(pageblock_default_order());
3522                setup_usemap(pgdat, zone, size);
3523                ret = init_currently_empty_zone(zone, zone_start_pfn,
3524                                                size, MEMMAP_EARLY);
3525                BUG_ON(ret);
3526                memmap_init(size, nid, j, zone_start_pfn);
3527                zone_start_pfn += size;
3528        }
3529}
3530
3531static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
3532{
3533        /* Skip empty nodes */
3534        if (!pgdat->node_spanned_pages)
3535                return;
3536
3537#ifdef CONFIG_FLAT_NODE_MEM_MAP
3538        /* ia64 gets its own node_mem_map, before this, without bootmem */
3539        if (!pgdat->node_mem_map) {
3540                unsigned long size, start, end;
3541                struct page *map;
3542
3543                /*
3544                 * The zone's endpoints aren't required to be MAX_ORDER
3545                 * aligned but the node_mem_map endpoints must be in order
3546                 * for the buddy allocator to function correctly.
3547                 */
3548                start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
3549                end = pgdat->node_start_pfn + pgdat->node_spanned_pages;
3550                end = ALIGN(end, MAX_ORDER_NR_PAGES);
3551                size =  (end - start) * sizeof(struct page);
3552                map = alloc_remap(pgdat->node_id, size);
3553                if (!map)
3554                        map = alloc_bootmem_node(pgdat, size);
3555                pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
3556        }
3557#ifndef CONFIG_NEED_MULTIPLE_NODES
3558        /*
3559         * With no DISCONTIG, the global mem_map is just set as node 0's
3560         */
3561        if (pgdat == NODE_DATA(0)) {
3562                mem_map = NODE_DATA(0)->node_mem_map;
3563#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
3564                if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
3565                        mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
3566#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
3567        }
3568#endif
3569#endif /* CONFIG_FLAT_NODE_MEM_MAP */
3570}
3571
3572void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
3573                unsigned long node_start_pfn, unsigned long *zholes_size)
3574{
3575        pg_data_t *pgdat = NODE_DATA(nid);
3576
3577        pgdat->node_id = nid;
3578        pgdat->node_start_pfn = node_start_pfn;
3579        calculate_node_totalpages(pgdat, zones_size, zholes_size);
3580
3581        alloc_node_mem_map(pgdat);
3582#ifdef CONFIG_FLAT_NODE_MEM_MAP
3583        printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
3584                nid, (unsigned long)pgdat,
3585                (unsigned long)pgdat->node_mem_map);
3586#endif
3587
3588        free_area_init_core(pgdat, zones_size, zholes_size);
3589}
3590
3591#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
3592
3593#if MAX_NUMNODES > 1
3594/*
3595 * Figure out the number of possible node ids.
3596 */
3597static void __init setup_nr_node_ids(void)
3598{
3599        unsigned int node;
3600        unsigned int highest = 0;
3601
3602        for_each_node_mask(node, node_possible_map)
3603                highest = node;
3604        nr_node_ids = highest + 1;
3605}
3606#else
3607static inline void setup_nr_node_ids(void)
3608{
3609}
3610#endif
3611
3612/**
3613 * add_active_range - Register a range of PFNs backed by physical memory
3614 * @nid: The node ID the range resides on
3615 * @start_pfn: The start PFN of the available physical memory
3616 * @end_pfn: The end PFN of the available physical memory
3617 *
3618 * These ranges are stored in an early_node_map[] and later used by
3619 * free_area_init_nodes() to calculate zone sizes and holes. If the
3620 * range spans a memory hole, it is up to the architecture to ensure
3621 * the memory is not freed by the bootmem allocator. If possible
3622 * the range being registered will be merged with existing ranges.
3623 */
3624void __init add_active_range(unsigned int nid, unsigned long start_pfn,
3625                                                unsigned long end_pfn)
3626{
3627        int i;
3628
3629        mminit_dprintk(MMINIT_TRACE, "memory_register",
3630                        "Entering add_active_range(%d, %#lx, %#lx) "
3631                        "%d entries of %d used\n",
3632                        nid, start_pfn, end_pfn,
3633                        nr_nodemap_entries, MAX_ACTIVE_REGIONS);
3634
3635        mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
3636
3637        /* Merge with existing active regions if possible */
3638        for (i = 0; i < nr_nodemap_entries; i++) {
3639                if (early_node_map[i].nid != nid)
3640                        continue;
3641
3642                /* Skip if an existing region covers this new one */
3643                if (start_pfn >= early_node_map[i].start_pfn &&
3644                                end_pfn <= early_node_map[i].end_pfn)
3645                        return;
3646
3647                /* Merge forward if suitable */
3648                if (start_pfn <= early_node_map[i].end_pfn &&
3649                                end_pfn > early_node_map[i].end_pfn) {
3650                        early_node_map[i].end_pfn = end_pfn;
3651                        return;
3652                }
3653
3654                /* Merge backward if suitable */
3655                if (start_pfn < early_node_map[i].end_pfn &&
3656                                end_pfn >= early_node_map[i].start_pfn) {
3657                        early_node_map[i].start_pfn = start_pfn;
3658                        return;
3659                }
3660        }
3661
3662        /* Check that early_node_map is large enough */
3663        if (i >= MAX_ACTIVE_REGIONS) {
3664                printk(KERN_CRIT "More than %d memory regions, truncating\n",
3665                                                        MAX_ACTIVE_REGIONS);
3666                return;
3667        }
3668
3669        early_node_map[i].nid = nid;
3670        early_node_map[i].start_pfn = start_pfn;
3671        early_node_map[i].end_pfn = end_pfn;
3672        nr_nodemap_entries = i + 1;
3673}
3674
3675/**
3676 * remove_active_range - Shrink an existing registered range of PFNs
3677 * @nid: The node id the range is on that should be shrunk
3678 * @start_pfn: The new PFN of the range
3679 * @end_pfn: The new PFN of the range
3680 *
3681 * i386 with NUMA use alloc_remap() to store a node_mem_map on a local node.
3682 * The map is kept near the end physical page range that has already been
3683 * registered. This function allows an arch to shrink an existing registered
3684 * range.
3685 */
3686void __init remove_active_range(unsigned int nid, unsigned long start_pfn,
3687                                unsigned long end_pfn)
3688{
3689        int i, j;
3690        int removed = 0;
3691
3692        printk(KERN_DEBUG "remove_active_range (%d, %lu, %lu)\n",
3693                          nid, start_pfn, end_pfn);
3694
3695        /* Find the old active region end and shrink */
3696        for_each_active_range_index_in_nid(i, nid) {
3697                if (early_node_map[i].start_pfn >= start_pfn &&
3698                    early_node_map[i].end_pfn <= end_pfn) {
3699                        /* clear it */
3700                        early_node_map[i].start_pfn = 0;
3701                        early_node_map[i].end_pfn = 0;
3702                        removed = 1;
3703                        continue;
3704                }
3705                if (early_node_map[i].start_pfn < start_pfn &&
3706                    early_node_map[i].end_pfn > start_pfn) {
3707                        unsigned long temp_end_pfn = early_node_map[i].end_pfn;
3708                        early_node_map[i].end_pfn = start_pfn;
3709                        if (temp_end_pfn > end_pfn)
3710                                add_active_range(nid, end_pfn, temp_end_pfn);
3711                        continue;
3712                }
3713                if (early_node_map[i].start_pfn >= start_pfn &&
3714                    early_node_map[i].end_pfn > end_pfn &&
3715                    early_node_map[i].start_pfn < end_pfn) {
3716                        early_node_map[i].start_pfn = end_pfn;
3717                        continue;
3718                }
3719        }
3720
3721        if (!removed)
3722                return;
3723
3724        /* remove the blank ones */
3725        for (i = nr_nodemap_entries - 1; i > 0; i--) {
3726                if (early_node_map[i].nid != nid)
3727                        continue;
3728                if (early_node_map[i].end_pfn)
3729                        continue;
3730                /* we found it, get rid of it */
3731                for (j = i; j < nr_nodemap_entries - 1; j++)
3732                        memcpy(&early_node_map[j], &early_node_map[j+1],
3733                                sizeof(early_node_map[j]));
3734                j = nr_nodemap_entries - 1;
3735                memset(&early_node_map[j], 0, sizeof(early_node_map[j]));
3736                nr_nodemap_entries--;
3737        }
3738}
3739
3740/**
3741 * remove_all_active_ranges - Remove all currently registered regions
3742 *
3743 * During discovery, it may be found that a table like SRAT is invalid
3744 * and an alternative discovery method must be used. This function removes
3745 * all currently registered regions.
3746 */
3747void __init remove_all_active_ranges(void)
3748{
3749        memset(early_node_map, 0, sizeof(early_node_map));
3750        nr_nodemap_entries = 0;
3751#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
3752        memset(node_boundary_start_pfn, 0, sizeof(node_boundary_start_pfn));
3753        memset(node_boundary_end_pfn, 0, sizeof(node_boundary_end_pfn));
3754#endif /* CONFIG_MEMORY_HOTPLUG_RESERVE */
3755}
3756
3757/* Compare two active node_active_regions */
3758static int __init cmp_node_active_region(const void *a, const void *b)
3759{
3760        struct node_active_region *arange = (struct node_active_region *)a;
3761        struct node_active_region *brange = (struct node_active_region *)b;
3762
3763        /* Done this way to avoid overflows */
3764        if (arange->start_pfn > brange->start_pfn)
3765                return 1;
3766        if (arange->start_pfn < brange->start_pfn)
3767                return -1;
3768
3769        return 0;
3770}
3771
3772/* sort the node_map by start_pfn */
3773static void __init sort_node_map(void)
3774{
3775        sort(early_node_map, (size_t)nr_nodemap_entries,
3776                        sizeof(struct node_active_region),
3777                        cmp_node_active_region, NULL);
3778}
3779
3780/* Find the lowest pfn for a node */
3781static unsigned long __init find_min_pfn_for_node(int nid)
3782{
3783        int i;
3784        unsigned long min_pfn = ULONG_MAX;
3785
3786        /* Assuming a sorted map, the first range found has the starting pfn */
3787        for_each_active_range_index_in_nid(i, nid)
3788                min_pfn = min(min_pfn, early_node_map[i].start_pfn);
3789
3790        if (min_pfn == ULONG_MAX) {
3791                printk(KERN_WARNING
3792                        "Could not find start_pfn for node %d\n", nid);
3793                return 0;
3794        }
3795
3796        return min_pfn;
3797}
3798
3799/**
3800 * find_min_pfn_with_active_regions - Find the minimum PFN registered
3801 *
3802 * It returns the minimum PFN based on information provided via
3803 * add_active_range().
3804 */
3805unsigned long __init find_min_pfn_with_active_regions(void)
3806{
3807        return find_min_pfn_for_node(MAX_NUMNODES);
3808}
3809
3810/*
3811 * early_calculate_totalpages()
3812 * Sum pages in active regions for movable zone.
3813 * Populate N_HIGH_MEMORY for calculating usable_nodes.
3814 */
3815static unsigned long __init early_calculate_totalpages(void)
3816{
3817        int i;
3818        unsigned long totalpages = 0;
3819
3820        for (i = 0; i < nr_nodemap_entries; i++) {
3821                unsigned long pages = early_node_map[i].end_pfn -
3822                                                early_node_map[i].start_pfn;
3823                totalpages += pages;
3824                if (pages)
3825                        node_set_state(early_node_map[i].nid, N_HIGH_MEMORY);
3826        }
3827        return totalpages;
3828}
3829
3830/*
3831 * Find the PFN the Movable zone begins in each node. Kernel memory
3832 * is spread evenly between nodes as long as the nodes have enough
3833 * memory. When they don't, some nodes will have more kernelcore than
3834 * others
3835 */
3836static void __init find_zone_movable_pfns_for_nodes(unsigned long *movable_pfn)
3837{
3838        int i, nid;
3839        unsigned long usable_startpfn;
3840        unsigned long kernelcore_node, kernelcore_remaining;
3841        unsigned long totalpages = early_calculate_totalpages();
3842        int usable_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
3843
3844        /*
3845         * If movablecore was specified, calculate what size of
3846         * kernelcore that corresponds so that memory usable for
3847         * any allocation type is evenly spread. If both kernelcore
3848         * and movablecore are specified, then the value of kernelcore
3849         * will be used for required_kernelcore if it's greater than
3850         * what movablecore would have allowed.
3851         */
3852        if (required_movablecore) {
3853                unsigned long corepages;
3854
3855                /*
3856                 * Round-up so that ZONE_MOVABLE is at least as large as what
3857                 * was requested by the user
3858                 */
3859                required_movablecore =
3860                        roundup(required_movablecore, MAX_ORDER_NR_PAGES);
3861                corepages = totalpages - required_movablecore;
3862
3863                required_kernelcore = max(required_kernelcore, corepages);
3864        }
3865
3866        /* If kernelcore was not specified, there is no ZONE_MOVABLE */
3867        if (!required_kernelcore)
3868                return;
3869
3870        /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
3871        find_usable_zone_for_movable();
3872        usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
3873
3874restart:
3875        /* Spread kernelcore memory as evenly as possible throughout nodes */
3876        kernelcore_node = required_kernelcore / usable_nodes;
3877        for_each_node_state(nid, N_HIGH_MEMORY) {
3878                /*
3879                 * Recalculate kernelcore_node if the division per node
3880                 * now exceeds what is necessary to satisfy the requested
3881                 * amount of memory for the kernel
3882                 */
3883                if (required_kernelcore < kernelcore_node)
3884                        kernelcore_node = required_kernelcore / usable_nodes;
3885
3886                /*
3887                 * As the map is walked, we track how much memory is usable
3888                 * by the kernel using kernelcore_remaining. When it is
3889                 * 0, the rest of the node is usable by ZONE_MOVABLE
3890                 */
3891                kernelcore_remaining = kernelcore_node;
3892
3893                /* Go through each range of PFNs within this node */
3894                for_each_active_range_index_in_nid(i, nid) {
3895                        unsigned long start_pfn, end_pfn;
3896                        unsigned long size_pages;
3897
3898                        start_pfn = max(early_node_map[i].start_pfn,
3899                                                zone_movable_pfn[nid]);
3900                        end_pfn = early_node_map[i].end_pfn;
3901                        if (start_pfn >= end_pfn)
3902                                continue;
3903
3904                        /* Account for what is only usable for kernelcore */
3905                        if (start_pfn < usable_startpfn) {
3906                                unsigned long kernel_pages;
3907                                kernel_pages = min(end_pfn, usable_startpfn)
3908                                                                - start_pfn;
3909
3910                                kernelcore_remaining -= min(kernel_pages,
3911                                                        kernelcore_remaining);
3912                                required_kernelcore -= min(kernel_pages,
3913                                                        required_kernelcore);
3914
3915                                /* Continue if range is now fully accounted */
3916                                if (end_pfn <= usable_startpfn) {
3917
3918                                        /*
3919                                         * Push zone_movable_pfn to the end so
3920                                         * that if we have to rebalance
3921                                         * kernelcore across nodes, we will
3922                                         * not double account here
3923                                         */
3924                                        zone_movable_pfn[nid] = end_pfn;
3925                                        continue;
3926                                }
3927                                start_pfn = usable_startpfn;
3928                        }
3929
3930                        /*
3931                         * The usable PFN range for ZONE_MOVABLE is from
3932                         * start_pfn->end_pfn. Calculate size_pages as the
3933                         * number of pages used as kernelcore
3934                         */
3935                        size_pages = end_pfn - start_pfn;
3936                        if (size_pages > kernelcore_remaining)
3937                                size_pages = kernelcore_remaining;
3938                        zone_movable_pfn[nid] = start_pfn + size_pages;
3939
3940                        /*
3941                         * Some kernelcore has been met, update counts and
3942                         * break if the kernelcore for this node has been
3943                         * satisified
3944                         */
3945                        required_kernelcore -= min(required_kernelcore,
3946                                                                size_pages);
3947                        kernelcore_remaining -= size_pages;
3948                        if (!kernelcore_remaining)
3949                                break;
3950                }
3951        }
3952
3953        /*
3954         * If there is still required_kernelcore, we do another pass with one
3955         * less node in the count. This will push zone_movable_pfn[nid] further
3956         * along on the nodes that still have memory until kernelcore is
3957         * satisified
3958         */
3959        usable_nodes--;
3960        if (usable_nodes && required_kernelcore > usable_nodes)
3961                goto restart;
3962
3963        /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
3964        for (nid = 0; nid < MAX_NUMNODES; nid++)
3965                zone_movable_pfn[nid] =
3966                        roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
3967}
3968
3969/* Any regular memory on that node ? */
3970static void check_for_regular_memory(pg_data_t *pgdat)
3971{
3972#ifdef CONFIG_HIGHMEM
3973        enum zone_type zone_type;
3974
3975        for (zone_type = 0; zone_type <= ZONE_NORMAL; zone_type++) {
3976                struct zone *zone = &pgdat->node_zones[zone_type];
3977                if (zone->present_pages)
3978                        node_set_state(zone_to_nid(zone), N_NORMAL_MEMORY);
3979        }
3980#endif
3981}
3982
3983/**
3984 * free_area_init_nodes - Initialise all pg_data_t and zone data
3985 * @max_zone_pfn: an array of max PFNs for each zone
3986 *
3987 * This will call free_area_init_node() for each active node in the system.
3988 * Using the page ranges provided by add_active_range(), the size of each
3989 * zone in each node and their holes is calculated. If the maximum PFN
3990 * between two adjacent zones match, it is assumed that the zone is empty.
3991 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
3992 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
3993 * starts where the previous one ended. For example, ZONE_DMA32 starts
3994 * at arch_max_dma_pfn.
3995 */
3996void __init free_area_init_nodes(unsigned long *max_zone_pfn)
3997{
3998        unsigned long nid;
3999        int i;
4000
4001        /* Sort early_node_map as initialisation assumes it is sorted */
4002        sort_node_map();
4003
4004        /* Record where the zone boundaries are */
4005        memset(arch_zone_lowest_possible_pfn, 0,
4006                                sizeof(arch_zone_lowest_possible_pfn));
4007        memset(arch_zone_highest_possible_pfn, 0,
4008                                sizeof(arch_zone_highest_possible_pfn));
4009        arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
4010        arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
4011        for (i = 1; i < MAX_NR_ZONES; i++) {
4012                if (i == ZONE_MOVABLE)
4013                        continue;
4014                arch_zone_lowest_possible_pfn[i] =
4015                        arch_zone_highest_possible_pfn[i-1];
4016                arch_zone_highest_possible_pfn[i] =
4017                        max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
4018        }
4019        arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
4020        arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
4021
4022        /* Find the PFNs that ZONE_MOVABLE begins at in each node */
4023        memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
4024        find_zone_movable_pfns_for_nodes(zone_movable_pfn);
4025
4026        /* Print out the zone ranges */
4027        printk("Zone PFN ranges:\n");
4028        for (i = 0; i < MAX_NR_ZONES; i++) {
4029                if (i == ZONE_MOVABLE)
4030                        continue;
4031                printk("  %-8s %0#10lx -> %0#10lx\n",
4032                                zone_names[i],
4033                                arch_zone_lowest_possible_pfn[i],
4034                                arch_zone_highest_possible_pfn[i]);
4035        }
4036
4037        /* Print out the PFNs ZONE_MOVABLE begins at in each node */
4038        printk("Movable zone start PFN for each node\n");
4039        for (i = 0; i < MAX_NUMNODES; i++) {
4040                if (zone_movable_pfn[i])
4041                        printk("  Node %d: %lu\n", i, zone_movable_pfn[i]);
4042        }
4043
4044        /* Print out the early_node_map[] */
4045        printk("early_node_map[%d] active PFN ranges\n", nr_nodemap_entries);
4046        for (i = 0; i < nr_nodemap_entries; i++)
4047                printk("  %3d: %0#10lx -> %0#10lx\n", early_node_map[i].nid,
4048                                                early_node_map[i].start_pfn,
4049                                                early_node_map[i].end_pfn);
4050
4051        /* Initialise every node */
4052        mminit_verify_pageflags_layout();
4053        setup_nr_node_ids();
4054        for_each_online_node(nid) {
4055                pg_data_t *pgdat = NODE_DATA(nid);
4056                free_area_init_node(nid, NULL,
4057                                find_min_pfn_for_node(nid), NULL);
4058
4059                /* Any memory on that node */
4060                if (pgdat->node_present_pages)
4061                        node_set_state(nid, N_HIGH_MEMORY);
4062                check_for_regular_memory(pgdat);
4063        }
4064}
4065
4066static int __init cmdline_parse_core(char *p, unsigned long *core)
4067{
4068        unsigned long long coremem;
4069        if (!p)
4070                return -EINVAL;
4071
4072        coremem = memparse(p, &p);
4073        *core = coremem >> PAGE_SHIFT;
4074
4075        /* Paranoid check that UL is enough for the coremem value */
4076        WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
4077
4078        return 0;
4079}
4080
4081/*
4082 * kernelcore=size sets the amount of memory for use for allocations that
4083 * cannot be reclaimed or migrated.
4084 */
4085static int __init cmdline_parse_kernelcore(char *p)
4086{
4087        return cmdline_parse_core(p, &required_kernelcore);
4088}
4089
4090/*
4091 * movablecore=size sets the amount of memory for use for allocations that
4092 * can be reclaimed or migrated.
4093 */
4094static int __init cmdline_parse_movablecore(char *p)
4095{
4096        return cmdline_parse_core(p, &required_movablecore);
4097}
4098
4099early_param("kernelcore", cmdline_parse_kernelcore);
4100early_param("movablecore", cmdline_parse_movablecore);
4101
4102#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
4103
4104/**
4105 * set_dma_reserve - set the specified number of pages reserved in the first zone
4106 * @new_dma_reserve: The number of pages to mark reserved
4107 *
4108 * The per-cpu batchsize and zone watermarks are determined by present_pages.
4109 * In the DMA zone, a significant percentage may be consumed by kernel image
4110 * and other unfreeable allocations which can skew the watermarks badly. This
4111 * function may optionally be used to account for unfreeable pages in the
4112 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
4113 * smaller per-cpu batchsize.
4114 */
4115void __init set_dma_reserve(unsigned long new_dma_reserve)
4116{
4117        dma_reserve = new_dma_reserve;
4118}
4119
4120#ifndef CONFIG_NEED_MULTIPLE_NODES
4121struct pglist_data __refdata contig_page_data = { .bdata = &bootmem_node_data[0] };
4122EXPORT_SYMBOL(contig_page_data);
4123#endif
4124
4125void __init free_area_init(unsigned long *zones_size)
4126{
4127        free_area_init_node(0, zones_size,
4128                        __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
4129}
4130
4131static int page_alloc_cpu_notify(struct notifier_block *self,
4132                                 unsigned long action, void *hcpu)
4133{
4134        int cpu = (unsigned long)hcpu;
4135
4136        if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
4137                drain_pages(cpu);
4138
4139                /*
4140                 * Spill the event counters of the dead processor
4141                 * into the current processors event counters.
4142                 * This artificially elevates the count of the current
4143                 * processor.
4144                 */
4145                vm_events_fold_cpu(cpu);
4146
4147                /*
4148                 * Zero the differential counters of the dead processor
4149                 * so that the vm statistics are consistent.
4150                 *
4151                 * This is only okay since the processor is dead and cannot
4152                 * race with what we are doing.
4153                 */
4154                refresh_cpu_vm_stats(cpu);
4155        }
4156        return NOTIFY_OK;
4157}
4158
4159void __init page_alloc_init(void)
4160{
4161        hotcpu_notifier(page_alloc_cpu_notify, 0);
4162}
4163
4164/*
4165 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
4166 *      or min_free_kbytes changes.
4167 */
4168static void calculate_totalreserve_pages(void)
4169{
4170        struct pglist_data *pgdat;
4171        unsigned long reserve_pages = 0;
4172        enum zone_type i, j;
4173
4174        for_each_online_pgdat(pgdat) {
4175                for (i = 0; i < MAX_NR_ZONES; i++) {
4176                        struct zone *zone = pgdat->node_zones + i;
4177                        unsigned long max = 0;
4178
4179                        /* Find valid and maximum lowmem_reserve in the zone */
4180                        for (j = i; j < MAX_NR_ZONES; j++) {
4181                                if (zone->lowmem_reserve[j] > max)
4182                                        max = zone->lowmem_reserve[j];
4183                        }
4184
4185                        /* we treat pages_high as reserved pages. */
4186                        max += zone->pages_high;
4187
4188                        if (max > zone->present_pages)
4189                                max = zone->present_pages;
4190                        reserve_pages += max;
4191                }
4192        }
4193        totalreserve_pages = reserve_pages;
4194}
4195
4196/*
4197 * setup_per_zone_lowmem_reserve - called whenever
4198 *      sysctl_lower_zone_reserve_ratio changes.  Ensures that each zone
4199 *      has a correct pages reserved value, so an adequate number of
4200 *      pages are left in the zone after a successful __alloc_pages().
4201 */
4202static void setup_per_zone_lowmem_reserve(void)
4203{
4204        struct pglist_data *pgdat;
4205        enum zone_type j, idx;
4206
4207        for_each_online_pgdat(pgdat) {
4208                for (j = 0; j < MAX_NR_ZONES; j++) {
4209                        struct zone *zone = pgdat->node_zones + j;
4210                        unsigned long present_pages = zone->present_pages;
4211
4212                        zone->lowmem_reserve[j] = 0;
4213
4214                        idx = j;
4215                        while (idx) {
4216                                struct zone *lower_zone;
4217
4218                                idx--;
4219
4220                                if (sysctl_lowmem_reserve_ratio[idx] < 1)
4221                                        sysctl_lowmem_reserve_ratio[idx] = 1;
4222
4223                                lower_zone = pgdat->node_zones + idx;
4224                                lower_zone->lowmem_reserve[j] = present_pages /
4225                                        sysctl_lowmem_reserve_ratio[idx];
4226                                present_pages += lower_zone->present_pages;
4227                        }
4228                }
4229        }
4230
4231        /* update totalreserve_pages */
4232        calculate_totalreserve_pages();
4233}
4234
4235/**
4236 * setup_per_zone_pages_min - called when min_free_kbytes changes.
4237 *
4238 * Ensures that the pages_{min,low,high} values for each zone are set correctly
4239 * with respect to min_free_kbytes.
4240 */
4241void setup_per_zone_pages_min(void)
4242{
4243        unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
4244        unsigned long lowmem_pages = 0;
4245        struct zone *zone;
4246        unsigned long flags;
4247
4248        /* Calculate total number of !ZONE_HIGHMEM pages */
4249        for_each_zone(zone) {
4250                if (!is_highmem(zone))
4251                        lowmem_pages += zone->present_pages;
4252        }
4253
4254        for_each_zone(zone) {
4255                u64 tmp;
4256
4257                spin_lock_irqsave(&zone->lock, flags);
4258                tmp = (u64)pages_min * zone->present_pages;
4259                do_div(tmp, lowmem_pages);
4260                if (is_highmem(zone)) {
4261                        /*
4262                         * __GFP_HIGH and PF_MEMALLOC allocations usually don't
4263                         * need highmem pages, so cap pages_min to a small
4264                         * value here.
4265                         *
4266                         * The (pages_high-pages_low) and (pages_low-pages_min)
4267                         * deltas controls asynch page reclaim, and so should
4268                         * not be capped for highmem.
4269                         */
4270                        int min_pages;
4271
4272                        min_pages = zone->present_pages / 1024;
4273                        if (min_pages < SWAP_CLUSTER_MAX)
4274                                min_pages = SWAP_CLUSTER_MAX;
4275                        if (min_pages > 128)
4276                                min_pages = 128;
4277                        zone->pages_min = min_pages;
4278                } else {
4279                        /*
4280                         * If it's a lowmem zone, reserve a number of pages
4281                         * proportionate to the zone's size.
4282                         */
4283                        zone->pages_min = tmp;
4284                }
4285
4286                zone->pages_low   = zone->pages_min + (tmp >> 2);
4287                zone->pages_high  = zone->pages_min + (tmp >> 1);
4288                setup_zone_migrate_reserve(zone);
4289                spin_unlock_irqrestore(&zone->lock, flags);
4290        }
4291
4292        /* update totalreserve_pages */
4293        calculate_totalreserve_pages();
4294}
4295
4296/**
4297 * setup_per_zone_inactive_ratio - called when min_free_kbytes changes.
4298 *
4299 * The inactive anon list should be small enough that the VM never has to
4300 * do too much work, but large enough that each inactive page has a chance
4301 * to be referenced again before it is swapped out.
4302 *
4303 * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
4304 * INACTIVE_ANON pages on this zone's LRU, maintained by the
4305 * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
4306 * the anonymous pages are kept on the inactive list.
4307 *
4308 * total     target    max
4309 * memory    ratio     inactive anon
4310 * -------------------------------------
4311 *   10MB       1         5MB
4312 *  100MB       1        50MB
4313 *    1GB       3       250MB
4314 *   10GB      10       0.9GB
4315 *  100GB      31         3GB
4316 *    1TB     101        10GB
4317 *   10TB     320        32GB
4318 */
4319void setup_per_zone_inactive_ratio(void)
4320{
4321        struct zone *zone;
4322
4323        for_each_zone(zone) {
4324                unsigned int gb, ratio;
4325
4326                /* Zone size in gigabytes */
4327                gb = zone->present_pages >> (30 - PAGE_SHIFT);
4328                ratio = int_sqrt(10 * gb);
4329                if (!ratio)
4330                        ratio = 1;
4331
4332                zone->inactive_ratio = ratio;
4333        }
4334}
4335
4336/*
4337 * Initialise min_free_kbytes.
4338 *
4339 * For small machines we want it small (128k min).  For large machines
4340 * we want it large (64MB max).  But it is not linear, because network
4341 * bandwidth does not increase linearly with machine size.  We use
4342 *
4343 *      min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
4344 *      min_free_kbytes = sqrt(lowmem_kbytes * 16)
4345 *
4346 * which yields
4347 *
4348 * 16MB:        512k
4349 * 32MB:        724k
4350 * 64MB:        1024k
4351 * 128MB:       1448k
4352 * 256MB:       2048k
4353 * 512MB:       2896k
4354 * 1024MB:      4096k
4355 * 2048MB:      5792k
4356 * 4096MB:      8192k
4357 * 8192MB:      11584k
4358 * 16384MB:     16384k
4359 */
4360static int __init init_per_zone_pages_min(void)
4361{
4362        unsigned long lowmem_kbytes;
4363
4364        lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
4365
4366        min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
4367        if (min_free_kbytes < 128)
4368                min_free_kbytes = 128;
4369        if (min_free_kbytes > 65536)
4370                min_free_kbytes = 65536;
4371        setup_per_zone_pages_min();
4372        setup_per_zone_lowmem_reserve();
4373        setup_per_zone_inactive_ratio();
4374        return 0;
4375}
4376module_init(init_per_zone_pages_min)
4377
4378/*
4379 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so 
4380 *      that we can call two helper functions whenever min_free_kbytes
4381 *      changes.
4382 */
4383int min_free_kbytes_sysctl_handler(ctl_table *table, int write, 
4384        struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
4385{
4386        proc_dointvec(table, write, file, buffer, length, ppos);
4387        if (write)
4388                setup_per_zone_pages_min();
4389        return 0;
4390}
4391
4392#ifdef CONFIG_NUMA
4393int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
4394        struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
4395{
4396        struct zone *zone;
4397        int rc;
4398
4399        rc = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
4400        if (rc)
4401                return rc;
4402
4403        for_each_zone(zone)
4404                zone->min_unmapped_pages = (zone->present_pages *
4405                                sysctl_min_unmapped_ratio) / 100;
4406        return 0;
4407}
4408
4409int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
4410        struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
4411{
4412        struct zone *zone;
4413        int rc;
4414
4415        rc = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
4416        if (rc)
4417                return rc;
4418
4419        for_each_zone(zone)
4420                zone->min_slab_pages = (zone->present_pages *
4421                                sysctl_min_slab_ratio) / 100;
4422        return 0;
4423}
4424#endif
4425
4426/*
4427 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
4428 *      proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
4429 *      whenever sysctl_lowmem_reserve_ratio changes.
4430 *
4431 * The reserve ratio obviously has absolutely no relation with the
4432 * pages_min watermarks. The lowmem reserve ratio can only make sense
4433 * if in function of the boot time zone sizes.
4434 */
4435int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
4436        struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
4437{
4438        proc_dointvec_minmax(table, write, file, buffer, length, ppos);
4439        setup_per_zone_lowmem_reserve();
4440        return 0;
4441}
4442
4443/*
4444 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
4445 * cpu.  It is the fraction of total pages in each zone that a hot per cpu pagelist
4446 * can have before it gets flushed back to buddy allocator.
4447 */
4448
4449int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
4450        struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
4451{
4452        struct zone *zone;
4453        unsigned int cpu;
4454        int ret;
4455
4456        ret = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
4457        if (!write || (ret == -EINVAL))
4458                return ret;
4459        for_each_zone(zone) {
4460                for_each_online_cpu(cpu) {
4461                        unsigned long  high;
4462                        high = zone->present_pages / percpu_pagelist_fraction;
4463                        setup_pagelist_highmark(zone_pcp(zone, cpu), high);
4464                }
4465        }
4466        return 0;
4467}
4468
4469int hashdist = HASHDIST_DEFAULT;
4470
4471#ifdef CONFIG_NUMA
4472static int __init set_hashdist(char *str)
4473{
4474        if (!str)
4475                return 0;
4476        hashdist = simple_strtoul(str, &str, 0);
4477        return 1;
4478}
4479__setup("hashdist=", set_hashdist);
4480#endif
4481
4482/*
4483 * allocate a large system hash table from bootmem
4484 * - it is assumed that the hash table must contain an exact power-of-2
4485 *   quantity of entries
4486 * - limit is the number of hash buckets, not the total allocation size
4487 */
4488void *__init alloc_large_system_hash(const char *tablename,
4489                                     unsigned long bucketsize,
4490                                     unsigned long numentries,
4491                                     int scale,
4492                                     int flags,
4493                                     unsigned int *_hash_shift,
4494                                     unsigned int *_hash_mask,
4495                                     unsigned long limit)
4496{
4497        unsigned long long max = limit;
4498        unsigned long log2qty, size;
4499        void *table = NULL;
4500
4501        /* allow the kernel cmdline to have a say */
4502        if (!numentries) {
4503                /* round applicable memory size up to nearest megabyte */
4504                numentries = nr_kernel_pages;
4505                numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
4506                numentries >>= 20 - PAGE_SHIFT;
4507                numentries <<= 20 - PAGE_SHIFT;
4508
4509                /* limit to 1 bucket per 2^scale bytes of low memory */
4510                if (scale > PAGE_SHIFT)
4511                        numentries >>= (scale - PAGE_SHIFT);
4512                else
4513                        numentries <<= (PAGE_SHIFT - scale);
4514
4515                /* Make sure we've got at least a 0-order allocation.. */
4516                if (unlikely((numentries * bucketsize) < PAGE_SIZE))
4517                        numentries = PAGE_SIZE / bucketsize;
4518        }
4519        numentries = roundup_pow_of_two(numentries);
4520
4521        /* limit allocation size to 1/16 total memory by default */
4522        if (max == 0) {
4523                max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
4524                do_div(max, bucketsize);
4525        }
4526
4527        if (numentries > max)
4528                numentries = max;
4529
4530        log2qty = ilog2(numentries);
4531
4532        do {
4533                size = bucketsize << log2qty;
4534                if (flags & HASH_EARLY)
4535                        table = alloc_bootmem_nopanic(size);
4536                else if (hashdist)
4537                        table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
4538                else {
4539                        unsigned long order = get_order(size);
4540                        table = (void*) __get_free_pages(GFP_ATOMIC, order);
4541                        /*
4542                         * If bucketsize is not a power-of-two, we may free
4543                         * some pages at the end of hash table.
4544                         */
4545                        if (table) {
4546                                unsigned long alloc_end = (unsigned long)table +
4547                                                (PAGE_SIZE << order);
4548                                unsigned long used = (unsigned long)table +
4549                                                PAGE_ALIGN(size);
4550                                split_page(virt_to_page(table), order);
4551                                while (used < alloc_end) {
4552                                        free_page(used);
4553                                        used += PAGE_SIZE;
4554                                }
4555                        }
4556                }
4557        } while (!table && size > PAGE_SIZE && --log2qty);
4558
4559        if (!table)
4560                panic("Failed to allocate %s hash table\n", tablename);
4561
4562        printk(KERN_INFO "%s hash table entries: %d (order: %d, %lu bytes)\n",
4563               tablename,
4564               (1U << log2qty),
4565               ilog2(size) - PAGE_SHIFT,
4566               size);
4567
4568        if (_hash_shift)
4569                *_hash_shift = log2qty;
4570        if (_hash_mask)
4571                *_hash_mask = (1 << log2qty) - 1;
4572
4573        return table;
4574}
4575
4576#ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
4577struct page *pfn_to_page(unsigned long pfn)
4578{
4579        return __pfn_to_page(pfn);
4580}
4581unsigned long page_to_pfn(struct page *page)
4582{
4583        return __page_to_pfn(page);
4584}
4585EXPORT_SYMBOL(pfn_to_page);
4586EXPORT_SYMBOL(page_to_pfn);
4587#endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */
4588
4589/* Return a pointer to the bitmap storing bits affecting a block of pages */
4590static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
4591                                                        unsigned long pfn)
4592{
4593#ifdef CONFIG_SPARSEMEM
4594        return __pfn_to_section(pfn)->pageblock_flags;
4595#else
4596        return zone->pageblock_flags;
4597#endif /* CONFIG_SPARSEMEM */
4598}
4599
4600static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
4601{
4602#ifdef CONFIG_SPARSEMEM
4603        pfn &= (PAGES_PER_SECTION-1);
4604        return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
4605#else
4606        pfn = pfn - zone->zone_start_pfn;
4607        return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
4608#endif /* CONFIG_SPARSEMEM */
4609}
4610
4611/**
4612 * get_pageblock_flags_group - Return the requested group of flags for the pageblock_nr_pages block of pages
4613 * @page: The page within the block of interest
4614 * @start_bitidx: The first bit of interest to retrieve
4615 * @end_bitidx: The last bit of interest
4616 * returns pageblock_bits flags
4617 */
4618unsigned long get_pageblock_flags_group(struct page *page,
4619                                        int start_bitidx, int end_bitidx)
4620{
4621        struct zone *zone;
4622        unsigned long *bitmap;
4623        unsigned long pfn, bitidx;
4624        unsigned long flags = 0;
4625        unsigned long value = 1;
4626
4627        zone = page_zone(page);
4628        pfn = page_to_pfn(page);
4629        bitmap = get_pageblock_bitmap(zone, pfn);
4630        bitidx = pfn_to_bitidx(zone, pfn);
4631
4632        for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
4633                if (test_bit(bitidx + start_bitidx, bitmap))
4634                        flags |= value;
4635
4636        return flags;
4637}
4638
4639/**
4640 * set_pageblock_flags_group - Set the requested group of flags for a pageblock_nr_pages block of pages
4641 * @page: The page within the block of interest
4642 * @start_bitidx: The first bit of interest
4643 * @end_bitidx: The last bit of interest
4644 * @flags: The flags to set
4645 */
4646void set_pageblock_flags_group(struct page *page, unsigned long flags,
4647                                        int start_bitidx, int end_bitidx)
4648{
4649        struct zone *zone;
4650        unsigned long *bitmap;
4651        unsigned long pfn, bitidx;
4652        unsigned long value = 1;
4653
4654        zone = page_zone(page);
4655        pfn = page_to_pfn(page);
4656        bitmap = get_pageblock_bitmap(zone, pfn);
4657        bitidx = pfn_to_bitidx(zone, pfn);
4658        VM_BUG_ON(pfn < zone->zone_start_pfn);
4659        VM_BUG_ON(pfn >= zone->zone_start_pfn + zone->spanned_pages);
4660
4661        for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
4662                if (flags & value)
4663                        __set_bit(bitidx + start_bitidx, bitmap);
4664                else
4665                        __clear_bit(bitidx + start_bitidx, bitmap);
4666}
4667
4668/*
4669 * This is designed as sub function...plz see page_isolation.c also.
4670 * set/clear page block's type to be ISOLATE.
4671 * page allocater never alloc memory from ISOLATE block.
4672 */
4673
4674int set_migratetype_isolate(struct page *page)
4675{
4676        struct zone *zone;
4677        unsigned long flags;
4678        int ret = -EBUSY;
4679
4680        zone = page_zone(page);
4681        spin_lock_irqsave(&zone->lock, flags);
4682        /*
4683         * In future, more migrate types will be able to be isolation target.
4684         */
4685        if (get_pageblock_migratetype(page) != MIGRATE_MOVABLE)
4686                goto out;
4687        set_pageblock_migratetype(page, MIGRATE_ISOLATE);
4688        move_freepages_block(zone, page, MIGRATE_ISOLATE);
4689        ret = 0;
4690out:
4691        spin_unlock_irqrestore(&zone->lock, flags);
4692        if (!ret)
4693                drain_all_pages();
4694        return ret;
4695}
4696
4697void unset_migratetype_isolate(struct page *page)
4698{
4699        struct zone *zone;
4700        unsigned long flags;
4701        zone = page_zone(page);
4702        spin_lock_irqsave(&zone->lock, flags);
4703        if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
4704                goto out;
4705        set_pageblock_migratetype(page, MIGRATE_MOVABLE);
4706        move_freepages_block(zone, page, MIGRATE_MOVABLE);
4707out:
4708        spin_unlock_irqrestore(&zone->lock, flags);
4709}
4710
4711#ifdef CONFIG_MEMORY_HOTREMOVE
4712/*
4713 * All pages in the range must be isolated before calling this.
4714 */
4715void
4716__offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
4717{
4718        struct page *page;
4719        struct zone *zone;
4720        int order, i;
4721        unsigned long pfn;
4722        unsigned long flags;
4723        /* find the first valid pfn */
4724        for (pfn = start_pfn; pfn < end_pfn; pfn++)
4725                if (pfn_valid(pfn))
4726                        break;
4727        if (pfn == end_pfn)
4728                return;
4729        zone = page_zone(pfn_to_page(pfn));
4730        spin_lock_irqsave(&zone->lock, flags);
4731        pfn = start_pfn;
4732        while (pfn < end_pfn) {
4733                if (!pfn_valid(pfn)) {
4734                        pfn++;
4735                        continue;
4736                }
4737                page = pfn_to_page(pfn);
4738                BUG_ON(page_count(page));
4739                BUG_ON(!PageBuddy(page));
4740                order = page_order(page);
4741#ifdef CONFIG_DEBUG_VM
4742                printk(KERN_INFO "remove from free list %lx %d %lx\n",
4743                       pfn, 1 << order, end_pfn);
4744#endif
4745                list_del(&page->lru);
4746                rmv_page_order(page);
4747                zone->free_area[order].nr_free--;
4748                __mod_zone_page_state(zone, NR_FREE_PAGES,
4749                                      - (1UL << order));
4750                for (i = 0; i < (1 << order); i++)
4751                        SetPageReserved((page+i));
4752                pfn += (1 << order);
4753        }
4754        spin_unlock_irqrestore(&zone->lock, flags);
4755}
4756#endif
4757