Root/mm/page_alloc.c

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/kmemcheck.h>
27#include <linux/module.h>
28#include <linux/suspend.h>
29#include <linux/pagevec.h>
30#include <linux/blkdev.h>
31#include <linux/slab.h>
32#include <linux/oom.h>
33#include <linux/notifier.h>
34#include <linux/topology.h>
35#include <linux/sysctl.h>
36#include <linux/cpu.h>
37#include <linux/cpuset.h>
38#include <linux/memory_hotplug.h>
39#include <linux/nodemask.h>
40#include <linux/vmalloc.h>
41#include <linux/mempolicy.h>
42#include <linux/stop_machine.h>
43#include <linux/sort.h>
44#include <linux/pfn.h>
45#include <linux/backing-dev.h>
46#include <linux/fault-inject.h>
47#include <linux/page-isolation.h>
48#include <linux/page_cgroup.h>
49#include <linux/debugobjects.h>
50#include <linux/kmemleak.h>
51#include <linux/memory.h>
52#include <linux/compaction.h>
53#include <trace/events/kmem.h>
54#include <linux/ftrace_event.h>
55
56#include <asm/tlbflush.h>
57#include <asm/div64.h>
58#include "internal.h"
59
60#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
61DEFINE_PER_CPU(int, numa_node);
62EXPORT_PER_CPU_SYMBOL(numa_node);
63#endif
64
65#ifdef CONFIG_HAVE_MEMORYLESS_NODES
66/*
67 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
68 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
69 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
70 * defined in <linux/topology.h>.
71 */
72DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */
73EXPORT_PER_CPU_SYMBOL(_numa_mem_);
74#endif
75
76/*
77 * Array of node states.
78 */
79nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
80    [N_POSSIBLE] = NODE_MASK_ALL,
81    [N_ONLINE] = { { [0] = 1UL } },
82#ifndef CONFIG_NUMA
83    [N_NORMAL_MEMORY] = { { [0] = 1UL } },
84#ifdef CONFIG_HIGHMEM
85    [N_HIGH_MEMORY] = { { [0] = 1UL } },
86#endif
87    [N_CPU] = { { [0] = 1UL } },
88#endif /* NUMA */
89};
90EXPORT_SYMBOL(node_states);
91
92unsigned long totalram_pages __read_mostly;
93unsigned long totalreserve_pages __read_mostly;
94int percpu_pagelist_fraction;
95gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
96
97#ifdef CONFIG_PM_SLEEP
98/*
99 * The following functions are used by the suspend/hibernate code to temporarily
100 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
101 * while devices are suspended. To avoid races with the suspend/hibernate code,
102 * they should always be called with pm_mutex held (gfp_allowed_mask also should
103 * only be modified with pm_mutex held, unless the suspend/hibernate code is
104 * guaranteed not to run in parallel with that modification).
105 */
106void set_gfp_allowed_mask(gfp_t mask)
107{
108    WARN_ON(!mutex_is_locked(&pm_mutex));
109    gfp_allowed_mask = mask;
110}
111
112gfp_t clear_gfp_allowed_mask(gfp_t mask)
113{
114    gfp_t ret = gfp_allowed_mask;
115
116    WARN_ON(!mutex_is_locked(&pm_mutex));
117    gfp_allowed_mask &= ~mask;
118    return ret;
119}
120#endif /* CONFIG_PM_SLEEP */
121
122#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
123int pageblock_order __read_mostly;
124#endif
125
126static void __free_pages_ok(struct page *page, unsigned int order);
127
128/*
129 * results with 256, 32 in the lowmem_reserve sysctl:
130 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
131 * 1G machine -> (16M dma, 784M normal, 224M high)
132 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
133 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
134 * HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
135 *
136 * TBD: should special case ZONE_DMA32 machines here - in those we normally
137 * don't need any ZONE_NORMAL reservation
138 */
139int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
140#ifdef CONFIG_ZONE_DMA
141     256,
142#endif
143#ifdef CONFIG_ZONE_DMA32
144     256,
145#endif
146#ifdef CONFIG_HIGHMEM
147     32,
148#endif
149     32,
150};
151
152EXPORT_SYMBOL(totalram_pages);
153
154static char * const zone_names[MAX_NR_ZONES] = {
155#ifdef CONFIG_ZONE_DMA
156     "DMA",
157#endif
158#ifdef CONFIG_ZONE_DMA32
159     "DMA32",
160#endif
161     "Normal",
162#ifdef CONFIG_HIGHMEM
163     "HighMem",
164#endif
165     "Movable",
166};
167
168int min_free_kbytes = 1024;
169
170static unsigned long __meminitdata nr_kernel_pages;
171static unsigned long __meminitdata nr_all_pages;
172static unsigned long __meminitdata dma_reserve;
173
174#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
175  /*
176   * MAX_ACTIVE_REGIONS determines the maximum number of distinct
177   * ranges of memory (RAM) that may be registered with add_active_range().
178   * Ranges passed to add_active_range() will be merged if possible
179   * so the number of times add_active_range() can be called is
180   * related to the number of nodes and the number of holes
181   */
182  #ifdef CONFIG_MAX_ACTIVE_REGIONS
183    /* Allow an architecture to set MAX_ACTIVE_REGIONS to save memory */
184    #define MAX_ACTIVE_REGIONS CONFIG_MAX_ACTIVE_REGIONS
185  #else
186    #if MAX_NUMNODES >= 32
187      /* If there can be many nodes, allow up to 50 holes per node */
188      #define MAX_ACTIVE_REGIONS (MAX_NUMNODES*50)
189    #else
190      /* By default, allow up to 256 distinct regions */
191      #define MAX_ACTIVE_REGIONS 256
192    #endif
193  #endif
194
195  static struct node_active_region __meminitdata early_node_map[MAX_ACTIVE_REGIONS];
196  static int __meminitdata nr_nodemap_entries;
197  static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
198  static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
199  static unsigned long __initdata required_kernelcore;
200  static unsigned long __initdata required_movablecore;
201  static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
202
203  /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
204  int movable_zone;
205  EXPORT_SYMBOL(movable_zone);
206#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
207
208#if MAX_NUMNODES > 1
209int nr_node_ids __read_mostly = MAX_NUMNODES;
210int nr_online_nodes __read_mostly = 1;
211EXPORT_SYMBOL(nr_node_ids);
212EXPORT_SYMBOL(nr_online_nodes);
213#endif
214
215int page_group_by_mobility_disabled __read_mostly;
216
217static void set_pageblock_migratetype(struct page *page, int migratetype)
218{
219
220    if (unlikely(page_group_by_mobility_disabled))
221        migratetype = MIGRATE_UNMOVABLE;
222
223    set_pageblock_flags_group(page, (unsigned long)migratetype,
224                    PB_migrate, PB_migrate_end);
225}
226
227bool oom_killer_disabled __read_mostly;
228
229#ifdef CONFIG_DEBUG_VM
230static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
231{
232    int ret = 0;
233    unsigned seq;
234    unsigned long pfn = page_to_pfn(page);
235
236    do {
237        seq = zone_span_seqbegin(zone);
238        if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
239            ret = 1;
240        else if (pfn < zone->zone_start_pfn)
241            ret = 1;
242    } while (zone_span_seqretry(zone, seq));
243
244    return ret;
245}
246
247static int page_is_consistent(struct zone *zone, struct page *page)
248{
249    if (!pfn_valid_within(page_to_pfn(page)))
250        return 0;
251    if (zone != page_zone(page))
252        return 0;
253
254    return 1;
255}
256/*
257 * Temporary debugging check for pages not lying within a given zone.
258 */
259static int bad_range(struct zone *zone, struct page *page)
260{
261    if (page_outside_zone_boundaries(zone, page))
262        return 1;
263    if (!page_is_consistent(zone, page))
264        return 1;
265
266    return 0;
267}
268#else
269static inline int bad_range(struct zone *zone, struct page *page)
270{
271    return 0;
272}
273#endif
274
275static void bad_page(struct page *page)
276{
277    static unsigned long resume;
278    static unsigned long nr_shown;
279    static unsigned long nr_unshown;
280
281    /* Don't complain about poisoned pages */
282    if (PageHWPoison(page)) {
283        __ClearPageBuddy(page);
284        return;
285    }
286
287    /*
288     * Allow a burst of 60 reports, then keep quiet for that minute;
289     * or allow a steady drip of one report per second.
290     */
291    if (nr_shown == 60) {
292        if (time_before(jiffies, resume)) {
293            nr_unshown++;
294            goto out;
295        }
296        if (nr_unshown) {
297            printk(KERN_ALERT
298                  "BUG: Bad page state: %lu messages suppressed\n",
299                nr_unshown);
300            nr_unshown = 0;
301        }
302        nr_shown = 0;
303    }
304    if (nr_shown++ == 0)
305        resume = jiffies + 60 * HZ;
306
307    printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n",
308        current->comm, page_to_pfn(page));
309    dump_page(page);
310
311    dump_stack();
312out:
313    /* Leave bad fields for debug, except PageBuddy could make trouble */
314    __ClearPageBuddy(page);
315    add_taint(TAINT_BAD_PAGE);
316}
317
318/*
319 * Higher-order pages are called "compound pages". They are structured thusly:
320 *
321 * The first PAGE_SIZE page is called the "head page".
322 *
323 * The remaining PAGE_SIZE pages are called "tail pages".
324 *
325 * All pages have PG_compound set. All pages have their ->private pointing at
326 * the head page (even the head page has this).
327 *
328 * The first tail page's ->lru.next holds the address of the compound page's
329 * put_page() function. Its ->lru.prev holds the order of allocation.
330 * This usage means that zero-order pages may not be compound.
331 */
332
333static void free_compound_page(struct page *page)
334{
335    __free_pages_ok(page, compound_order(page));
336}
337
338void prep_compound_page(struct page *page, unsigned long order)
339{
340    int i;
341    int nr_pages = 1 << order;
342
343    set_compound_page_dtor(page, free_compound_page);
344    set_compound_order(page, order);
345    __SetPageHead(page);
346    for (i = 1; i < nr_pages; i++) {
347        struct page *p = page + i;
348
349        __SetPageTail(p);
350        p->first_page = page;
351    }
352}
353
354static int destroy_compound_page(struct page *page, unsigned long order)
355{
356    int i;
357    int nr_pages = 1 << order;
358    int bad = 0;
359
360    if (unlikely(compound_order(page) != order) ||
361        unlikely(!PageHead(page))) {
362        bad_page(page);
363        bad++;
364    }
365
366    __ClearPageHead(page);
367
368    for (i = 1; i < nr_pages; i++) {
369        struct page *p = page + i;
370
371        if (unlikely(!PageTail(p) || (p->first_page != page))) {
372            bad_page(page);
373            bad++;
374        }
375        __ClearPageTail(p);
376    }
377
378    return bad;
379}
380
381static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
382{
383    int i;
384
385    /*
386     * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
387     * and __GFP_HIGHMEM from hard or soft interrupt context.
388     */
389    VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
390    for (i = 0; i < (1 << order); i++)
391        clear_highpage(page + i);
392}
393
394static inline void set_page_order(struct page *page, int order)
395{
396    set_page_private(page, order);
397    __SetPageBuddy(page);
398}
399
400static inline void rmv_page_order(struct page *page)
401{
402    __ClearPageBuddy(page);
403    set_page_private(page, 0);
404}
405
406/*
407 * Locate the struct page for both the matching buddy in our
408 * pair (buddy1) and the combined O(n+1) page they form (page).
409 *
410 * 1) Any buddy B1 will have an order O twin B2 which satisfies
411 * the following equation:
412 * B2 = B1 ^ (1 << O)
413 * For example, if the starting buddy (buddy2) is #8 its order
414 * 1 buddy is #10:
415 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
416 *
417 * 2) Any buddy B will have an order O+1 parent P which
418 * satisfies the following equation:
419 * P = B & ~(1 << O)
420 *
421 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
422 */
423static inline struct page *
424__page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
425{
426    unsigned long buddy_idx = page_idx ^ (1 << order);
427
428    return page + (buddy_idx - page_idx);
429}
430
431static inline unsigned long
432__find_combined_index(unsigned long page_idx, unsigned int order)
433{
434    return (page_idx & ~(1 << order));
435}
436
437/*
438 * This function checks whether a page is free && is the buddy
439 * we can do coalesce a page and its buddy if
440 * (a) the buddy is not in a hole &&
441 * (b) the buddy is in the buddy system &&
442 * (c) a page and its buddy have the same order &&
443 * (d) a page and its buddy are in the same zone.
444 *
445 * For recording whether a page is in the buddy system, we use PG_buddy.
446 * Setting, clearing, and testing PG_buddy is serialized by zone->lock.
447 *
448 * For recording page's order, we use page_private(page).
449 */
450static inline int page_is_buddy(struct page *page, struct page *buddy,
451                                int order)
452{
453    if (!pfn_valid_within(page_to_pfn(buddy)))
454        return 0;
455
456    if (page_zone_id(page) != page_zone_id(buddy))
457        return 0;
458
459    if (PageBuddy(buddy) && page_order(buddy) == order) {
460        VM_BUG_ON(page_count(buddy) != 0);
461        return 1;
462    }
463    return 0;
464}
465
466/*
467 * Freeing function for a buddy system allocator.
468 *
469 * The concept of a buddy system is to maintain direct-mapped table
470 * (containing bit values) for memory blocks of various "orders".
471 * The bottom level table contains the map for the smallest allocatable
472 * units of memory (here, pages), and each level above it describes
473 * pairs of units from the levels below, hence, "buddies".
474 * At a high level, all that happens here is marking the table entry
475 * at the bottom level available, and propagating the changes upward
476 * as necessary, plus some accounting needed to play nicely with other
477 * parts of the VM system.
478 * At each level, we keep a list of pages, which are heads of continuous
479 * free pages of length of (1 << order) and marked with PG_buddy. Page's
480 * order is recorded in page_private(page) field.
481 * So when we are allocating or freeing one, we can derive the state of the
482 * other. That is, if we allocate a small block, and both were
483 * free, the remainder of the region must be split into blocks.
484 * If a block is freed, and its buddy is also free, then this
485 * triggers coalescing into a block of larger size.
486 *
487 * -- wli
488 */
489
490static inline void __free_one_page(struct page *page,
491        struct zone *zone, unsigned int order,
492        int migratetype)
493{
494    unsigned long page_idx;
495    unsigned long combined_idx;
496    struct page *buddy;
497
498    if (unlikely(PageCompound(page)))
499        if (unlikely(destroy_compound_page(page, order)))
500            return;
501
502    VM_BUG_ON(migratetype == -1);
503
504    page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
505
506    VM_BUG_ON(page_idx & ((1 << order) - 1));
507    VM_BUG_ON(bad_range(zone, page));
508
509    while (order < MAX_ORDER-1) {
510        buddy = __page_find_buddy(page, page_idx, order);
511        if (!page_is_buddy(page, buddy, order))
512            break;
513
514        /* Our buddy is free, merge with it and move up one order. */
515        list_del(&buddy->lru);
516        zone->free_area[order].nr_free--;
517        rmv_page_order(buddy);
518        combined_idx = __find_combined_index(page_idx, order);
519        page = page + (combined_idx - page_idx);
520        page_idx = combined_idx;
521        order++;
522    }
523    set_page_order(page, order);
524
525    /*
526     * If this is not the largest possible page, check if the buddy
527     * of the next-highest order is free. If it is, it's possible
528     * that pages are being freed that will coalesce soon. In case,
529     * that is happening, add the free page to the tail of the list
530     * so it's less likely to be used soon and more likely to be merged
531     * as a higher order page
532     */
533    if ((order < MAX_ORDER-1) && pfn_valid_within(page_to_pfn(buddy))) {
534        struct page *higher_page, *higher_buddy;
535        combined_idx = __find_combined_index(page_idx, order);
536        higher_page = page + combined_idx - page_idx;
537        higher_buddy = __page_find_buddy(higher_page, combined_idx, order + 1);
538        if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
539            list_add_tail(&page->lru,
540                &zone->free_area[order].free_list[migratetype]);
541            goto out;
542        }
543    }
544
545    list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
546out:
547    zone->free_area[order].nr_free++;
548}
549
550/*
551 * free_page_mlock() -- clean up attempts to free and mlocked() page.
552 * Page should not be on lru, so no need to fix that up.
553 * free_pages_check() will verify...
554 */
555static inline void free_page_mlock(struct page *page)
556{
557    __dec_zone_page_state(page, NR_MLOCK);
558    __count_vm_event(UNEVICTABLE_MLOCKFREED);
559}
560
561static inline int free_pages_check(struct page *page)
562{
563    if (unlikely(page_mapcount(page) |
564        (page->mapping != NULL) |
565        (atomic_read(&page->_count) != 0) |
566        (page->flags & PAGE_FLAGS_CHECK_AT_FREE))) {
567        bad_page(page);
568        return 1;
569    }
570    if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
571        page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
572    return 0;
573}
574
575/*
576 * Frees a number of pages from the PCP lists
577 * Assumes all pages on list are in same zone, and of same order.
578 * count is the number of pages to free.
579 *
580 * If the zone was previously in an "all pages pinned" state then look to
581 * see if this freeing clears that state.
582 *
583 * And clear the zone's pages_scanned counter, to hold off the "all pages are
584 * pinned" detection logic.
585 */
586static void free_pcppages_bulk(struct zone *zone, int count,
587                    struct per_cpu_pages *pcp)
588{
589    int migratetype = 0;
590    int batch_free = 0;
591    int to_free = count;
592
593    spin_lock(&zone->lock);
594    zone->all_unreclaimable = 0;
595    zone->pages_scanned = 0;
596
597    while (to_free) {
598        struct page *page;
599        struct list_head *list;
600
601        /*
602         * Remove pages from lists in a round-robin fashion. A
603         * batch_free count is maintained that is incremented when an
604         * empty list is encountered. This is so more pages are freed
605         * off fuller lists instead of spinning excessively around empty
606         * lists
607         */
608        do {
609            batch_free++;
610            if (++migratetype == MIGRATE_PCPTYPES)
611                migratetype = 0;
612            list = &pcp->lists[migratetype];
613        } while (list_empty(list));
614
615        do {
616            page = list_entry(list->prev, struct page, lru);
617            /* must delete as __free_one_page list manipulates */
618            list_del(&page->lru);
619            /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
620            __free_one_page(page, zone, 0, page_private(page));
621            trace_mm_page_pcpu_drain(page, 0, page_private(page));
622        } while (--to_free && --batch_free && !list_empty(list));
623    }
624    __mod_zone_page_state(zone, NR_FREE_PAGES, count);
625    spin_unlock(&zone->lock);
626}
627
628static void free_one_page(struct zone *zone, struct page *page, int order,
629                int migratetype)
630{
631    spin_lock(&zone->lock);
632    zone->all_unreclaimable = 0;
633    zone->pages_scanned = 0;
634
635    __free_one_page(page, zone, order, migratetype);
636    __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
637    spin_unlock(&zone->lock);
638}
639
640static bool free_pages_prepare(struct page *page, unsigned int order)
641{
642    int i;
643    int bad = 0;
644
645    trace_mm_page_free_direct(page, order);
646    kmemcheck_free_shadow(page, order);
647
648    for (i = 0; i < (1 << order); i++) {
649        struct page *pg = page + i;
650
651        if (PageAnon(pg))
652            pg->mapping = NULL;
653        bad += free_pages_check(pg);
654    }
655    if (bad)
656        return false;
657
658    if (!PageHighMem(page)) {
659        debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
660        debug_check_no_obj_freed(page_address(page),
661                       PAGE_SIZE << order);
662    }
663    arch_free_page(page, order);
664    kernel_map_pages(page, 1 << order, 0);
665
666    return true;
667}
668
669static void __free_pages_ok(struct page *page, unsigned int order)
670{
671    unsigned long flags;
672    int wasMlocked = __TestClearPageMlocked(page);
673
674    if (!free_pages_prepare(page, order))
675        return;
676
677    local_irq_save(flags);
678    if (unlikely(wasMlocked))
679        free_page_mlock(page);
680    __count_vm_events(PGFREE, 1 << order);
681    free_one_page(page_zone(page), page, order,
682                    get_pageblock_migratetype(page));
683    local_irq_restore(flags);
684}
685
686/*
687 * permit the bootmem allocator to evade page validation on high-order frees
688 */
689void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
690{
691    if (order == 0) {
692        __ClearPageReserved(page);
693        set_page_count(page, 0);
694        set_page_refcounted(page);
695        __free_page(page);
696    } else {
697        int loop;
698
699        prefetchw(page);
700        for (loop = 0; loop < BITS_PER_LONG; loop++) {
701            struct page *p = &page[loop];
702
703            if (loop + 1 < BITS_PER_LONG)
704                prefetchw(p + 1);
705            __ClearPageReserved(p);
706            set_page_count(p, 0);
707        }
708
709        set_page_refcounted(page);
710        __free_pages(page, order);
711    }
712}
713
714
715/*
716 * The order of subdivision here is critical for the IO subsystem.
717 * Please do not alter this order without good reasons and regression
718 * testing. Specifically, as large blocks of memory are subdivided,
719 * the order in which smaller blocks are delivered depends on the order
720 * they're subdivided in this function. This is the primary factor
721 * influencing the order in which pages are delivered to the IO
722 * subsystem according to empirical testing, and this is also justified
723 * by considering the behavior of a buddy system containing a single
724 * large block of memory acted on by a series of small allocations.
725 * This behavior is a critical factor in sglist merging's success.
726 *
727 * -- wli
728 */
729static inline void expand(struct zone *zone, struct page *page,
730    int low, int high, struct free_area *area,
731    int migratetype)
732{
733    unsigned long size = 1 << high;
734
735    while (high > low) {
736        area--;
737        high--;
738        size >>= 1;
739        VM_BUG_ON(bad_range(zone, &page[size]));
740        list_add(&page[size].lru, &area->free_list[migratetype]);
741        area->nr_free++;
742        set_page_order(&page[size], high);
743    }
744}
745
746/*
747 * This page is about to be returned from the page allocator
748 */
749static inline int check_new_page(struct page *page)
750{
751    if (unlikely(page_mapcount(page) |
752        (page->mapping != NULL) |
753        (atomic_read(&page->_count) != 0) |
754        (page->flags & PAGE_FLAGS_CHECK_AT_PREP))) {
755        bad_page(page);
756        return 1;
757    }
758    return 0;
759}
760
761static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
762{
763    int i;
764
765    for (i = 0; i < (1 << order); i++) {
766        struct page *p = page + i;
767        if (unlikely(check_new_page(p)))
768            return 1;
769    }
770
771    set_page_private(page, 0);
772    set_page_refcounted(page);
773
774    arch_alloc_page(page, order);
775    kernel_map_pages(page, 1 << order, 1);
776
777    if (gfp_flags & __GFP_ZERO)
778        prep_zero_page(page, order, gfp_flags);
779
780    if (order && (gfp_flags & __GFP_COMP))
781        prep_compound_page(page, order);
782
783    return 0;
784}
785
786/*
787 * Go through the free lists for the given migratetype and remove
788 * the smallest available page from the freelists
789 */
790static inline
791struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
792                        int migratetype)
793{
794    unsigned int current_order;
795    struct free_area * area;
796    struct page *page;
797
798    /* Find a page of the appropriate size in the preferred list */
799    for (current_order = order; current_order < MAX_ORDER; ++current_order) {
800        area = &(zone->free_area[current_order]);
801        if (list_empty(&area->free_list[migratetype]))
802            continue;
803
804        page = list_entry(area->free_list[migratetype].next,
805                            struct page, lru);
806        list_del(&page->lru);
807        rmv_page_order(page);
808        area->nr_free--;
809        expand(zone, page, order, current_order, area, migratetype);
810        return page;
811    }
812
813    return NULL;
814}
815
816
817/*
818 * This array describes the order lists are fallen back to when
819 * the free lists for the desirable migrate type are depleted
820 */
821static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = {
822    [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
823    [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
824    [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
825    [MIGRATE_RESERVE] = { MIGRATE_RESERVE, MIGRATE_RESERVE, MIGRATE_RESERVE }, /* Never used */
826};
827
828/*
829 * Move the free pages in a range to the free lists of the requested type.
830 * Note that start_page and end_pages are not aligned on a pageblock
831 * boundary. If alignment is required, use move_freepages_block()
832 */
833static int move_freepages(struct zone *zone,
834              struct page *start_page, struct page *end_page,
835              int migratetype)
836{
837    struct page *page;
838    unsigned long order;
839    int pages_moved = 0;
840
841#ifndef CONFIG_HOLES_IN_ZONE
842    /*
843     * page_zone is not safe to call in this context when
844     * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
845     * anyway as we check zone boundaries in move_freepages_block().
846     * Remove at a later date when no bug reports exist related to
847     * grouping pages by mobility
848     */
849    BUG_ON(page_zone(start_page) != page_zone(end_page));
850#endif
851
852    for (page = start_page; page <= end_page;) {
853        /* Make sure we are not inadvertently changing nodes */
854        VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
855
856        if (!pfn_valid_within(page_to_pfn(page))) {
857            page++;
858            continue;
859        }
860
861        if (!PageBuddy(page)) {
862            page++;
863            continue;
864        }
865
866        order = page_order(page);
867        list_del(&page->lru);
868        list_add(&page->lru,
869            &zone->free_area[order].free_list[migratetype]);
870        page += 1 << order;
871        pages_moved += 1 << order;
872    }
873
874    return pages_moved;
875}
876
877static int move_freepages_block(struct zone *zone, struct page *page,
878                int migratetype)
879{
880    unsigned long start_pfn, end_pfn;
881    struct page *start_page, *end_page;
882
883    start_pfn = page_to_pfn(page);
884    start_pfn = start_pfn & ~(pageblock_nr_pages-1);
885    start_page = pfn_to_page(start_pfn);
886    end_page = start_page + pageblock_nr_pages - 1;
887    end_pfn = start_pfn + pageblock_nr_pages - 1;
888
889    /* Do not cross zone boundaries */
890    if (start_pfn < zone->zone_start_pfn)
891        start_page = page;
892    if (end_pfn >= zone->zone_start_pfn + zone->spanned_pages)
893        return 0;
894
895    return move_freepages(zone, start_page, end_page, migratetype);
896}
897
898static void change_pageblock_range(struct page *pageblock_page,
899                    int start_order, int migratetype)
900{
901    int nr_pageblocks = 1 << (start_order - pageblock_order);
902
903    while (nr_pageblocks--) {
904        set_pageblock_migratetype(pageblock_page, migratetype);
905        pageblock_page += pageblock_nr_pages;
906    }
907}
908
909/* Remove an element from the buddy allocator from the fallback list */
910static inline struct page *
911__rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
912{
913    struct free_area * area;
914    int current_order;
915    struct page *page;
916    int migratetype, i;
917
918    /* Find the largest possible block of pages in the other list */
919    for (current_order = MAX_ORDER-1; current_order >= order;
920                        --current_order) {
921        for (i = 0; i < MIGRATE_TYPES - 1; i++) {
922            migratetype = fallbacks[start_migratetype][i];
923
924            /* MIGRATE_RESERVE handled later if necessary */
925            if (migratetype == MIGRATE_RESERVE)
926                continue;
927
928            area = &(zone->free_area[current_order]);
929            if (list_empty(&area->free_list[migratetype]))
930                continue;
931
932            page = list_entry(area->free_list[migratetype].next,
933                    struct page, lru);
934            area->nr_free--;
935
936            /*
937             * If breaking a large block of pages, move all free
938             * pages to the preferred allocation list. If falling
939             * back for a reclaimable kernel allocation, be more
940             * agressive about taking ownership of free pages
941             */
942            if (unlikely(current_order >= (pageblock_order >> 1)) ||
943                    start_migratetype == MIGRATE_RECLAIMABLE ||
944                    page_group_by_mobility_disabled) {
945                unsigned long pages;
946                pages = move_freepages_block(zone, page,
947                                start_migratetype);
948
949                /* Claim the whole block if over half of it is free */
950                if (pages >= (1 << (pageblock_order-1)) ||
951                        page_group_by_mobility_disabled)
952                    set_pageblock_migratetype(page,
953                                start_migratetype);
954
955                migratetype = start_migratetype;
956            }
957
958            /* Remove the page from the freelists */
959            list_del(&page->lru);
960            rmv_page_order(page);
961
962            /* Take ownership for orders >= pageblock_order */
963            if (current_order >= pageblock_order)
964                change_pageblock_range(page, current_order,
965                            start_migratetype);
966
967            expand(zone, page, order, current_order, area, migratetype);
968
969            trace_mm_page_alloc_extfrag(page, order, current_order,
970                start_migratetype, migratetype);
971
972            return page;
973        }
974    }
975
976    return NULL;
977}
978
979/*
980 * Do the hard work of removing an element from the buddy allocator.
981 * Call me with the zone->lock already held.
982 */
983static struct page *__rmqueue(struct zone *zone, unsigned int order,
984                        int migratetype)
985{
986    struct page *page;
987
988retry_reserve:
989    page = __rmqueue_smallest(zone, order, migratetype);
990
991    if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
992        page = __rmqueue_fallback(zone, order, migratetype);
993
994        /*
995         * Use MIGRATE_RESERVE rather than fail an allocation. goto
996         * is used because __rmqueue_smallest is an inline function
997         * and we want just one call site
998         */
999        if (!page) {
1000            migratetype = MIGRATE_RESERVE;
1001            goto retry_reserve;
1002        }
1003    }
1004
1005    trace_mm_page_alloc_zone_locked(page, order, migratetype);
1006    return page;
1007}
1008
1009/*
1010 * Obtain a specified number of elements from the buddy allocator, all under
1011 * a single hold of the lock, for efficiency. Add them to the supplied list.
1012 * Returns the number of new pages which were placed at *list.
1013 */
1014static int rmqueue_bulk(struct zone *zone, unsigned int order,
1015            unsigned long count, struct list_head *list,
1016            int migratetype, int cold)
1017{
1018    int i;
1019    
1020    spin_lock(&zone->lock);
1021    for (i = 0; i < count; ++i) {
1022        struct page *page = __rmqueue(zone, order, migratetype);
1023        if (unlikely(page == NULL))
1024            break;
1025
1026        /*
1027         * Split buddy pages returned by expand() are received here
1028         * in physical page order. The page is added to the callers and
1029         * list and the list head then moves forward. From the callers
1030         * perspective, the linked list is ordered by page number in
1031         * some conditions. This is useful for IO devices that can
1032         * merge IO requests if the physical pages are ordered
1033         * properly.
1034         */
1035        if (likely(cold == 0))
1036            list_add(&page->lru, list);
1037        else
1038            list_add_tail(&page->lru, list);
1039        set_page_private(page, migratetype);
1040        list = &page->lru;
1041    }
1042    __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
1043    spin_unlock(&zone->lock);
1044    return i;
1045}
1046
1047#ifdef CONFIG_NUMA
1048/*
1049 * Called from the vmstat counter updater to drain pagesets of this
1050 * currently executing processor on remote nodes after they have
1051 * expired.
1052 *
1053 * Note that this function must be called with the thread pinned to
1054 * a single processor.
1055 */
1056void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
1057{
1058    unsigned long flags;
1059    int to_drain;
1060
1061    local_irq_save(flags);
1062    if (pcp->count >= pcp->batch)
1063        to_drain = pcp->batch;
1064    else
1065        to_drain = pcp->count;
1066    free_pcppages_bulk(zone, to_drain, pcp);
1067    pcp->count -= to_drain;
1068    local_irq_restore(flags);
1069}
1070#endif
1071
1072/*
1073 * Drain pages of the indicated processor.
1074 *
1075 * The processor must either be the current processor and the
1076 * thread pinned to the current processor or a processor that
1077 * is not online.
1078 */
1079static void drain_pages(unsigned int cpu)
1080{
1081    unsigned long flags;
1082    struct zone *zone;
1083
1084    for_each_populated_zone(zone) {
1085        struct per_cpu_pageset *pset;
1086        struct per_cpu_pages *pcp;
1087
1088        local_irq_save(flags);
1089        pset = per_cpu_ptr(zone->pageset, cpu);
1090
1091        pcp = &pset->pcp;
1092        free_pcppages_bulk(zone, pcp->count, pcp);
1093        pcp->count = 0;
1094        local_irq_restore(flags);
1095    }
1096}
1097
1098/*
1099 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
1100 */
1101void drain_local_pages(void *arg)
1102{
1103    drain_pages(smp_processor_id());
1104}
1105
1106/*
1107 * Spill all the per-cpu pages from all CPUs back into the buddy allocator
1108 */
1109void drain_all_pages(void)
1110{
1111    on_each_cpu(drain_local_pages, NULL, 1);
1112}
1113
1114#ifdef CONFIG_HIBERNATION
1115
1116void mark_free_pages(struct zone *zone)
1117{
1118    unsigned long pfn, max_zone_pfn;
1119    unsigned long flags;
1120    int order, t;
1121    struct list_head *curr;
1122
1123    if (!zone->spanned_pages)
1124        return;
1125
1126    spin_lock_irqsave(&zone->lock, flags);
1127
1128    max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1129    for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1130        if (pfn_valid(pfn)) {
1131            struct page *page = pfn_to_page(pfn);
1132
1133            if (!swsusp_page_is_forbidden(page))
1134                swsusp_unset_page_free(page);
1135        }
1136
1137    for_each_migratetype_order(order, t) {
1138        list_for_each(curr, &zone->free_area[order].free_list[t]) {
1139            unsigned long i;
1140
1141            pfn = page_to_pfn(list_entry(curr, struct page, lru));
1142            for (i = 0; i < (1UL << order); i++)
1143                swsusp_set_page_free(pfn_to_page(pfn + i));
1144        }
1145    }
1146    spin_unlock_irqrestore(&zone->lock, flags);
1147}
1148#endif /* CONFIG_PM */
1149
1150/*
1151 * Free a 0-order page
1152 * cold == 1 ? free a cold page : free a hot page
1153 */
1154void free_hot_cold_page(struct page *page, int cold)
1155{
1156    struct zone *zone = page_zone(page);
1157    struct per_cpu_pages *pcp;
1158    unsigned long flags;
1159    int migratetype;
1160    int wasMlocked = __TestClearPageMlocked(page);
1161
1162    if (!free_pages_prepare(page, 0))
1163        return;
1164
1165    migratetype = get_pageblock_migratetype(page);
1166    set_page_private(page, migratetype);
1167    local_irq_save(flags);
1168    if (unlikely(wasMlocked))
1169        free_page_mlock(page);
1170    __count_vm_event(PGFREE);
1171
1172    /*
1173     * We only track unmovable, reclaimable and movable on pcp lists.
1174     * Free ISOLATE pages back to the allocator because they are being
1175     * offlined but treat RESERVE as movable pages so we can get those
1176     * areas back if necessary. Otherwise, we may have to free
1177     * excessively into the page allocator
1178     */
1179    if (migratetype >= MIGRATE_PCPTYPES) {
1180        if (unlikely(migratetype == MIGRATE_ISOLATE)) {
1181            free_one_page(zone, page, 0, migratetype);
1182            goto out;
1183        }
1184        migratetype = MIGRATE_MOVABLE;
1185    }
1186
1187    pcp = &this_cpu_ptr(zone->pageset)->pcp;
1188    if (cold)
1189        list_add_tail(&page->lru, &pcp->lists[migratetype]);
1190    else
1191        list_add(&page->lru, &pcp->lists[migratetype]);
1192    pcp->count++;
1193    if (pcp->count >= pcp->high) {
1194        free_pcppages_bulk(zone, pcp->batch, pcp);
1195        pcp->count -= pcp->batch;
1196    }
1197
1198out:
1199    local_irq_restore(flags);
1200}
1201
1202/*
1203 * split_page takes a non-compound higher-order page, and splits it into
1204 * n (1<<order) sub-pages: page[0..n]
1205 * Each sub-page must be freed individually.
1206 *
1207 * Note: this is probably too low level an operation for use in drivers.
1208 * Please consult with lkml before using this in your driver.
1209 */
1210void split_page(struct page *page, unsigned int order)
1211{
1212    int i;
1213
1214    VM_BUG_ON(PageCompound(page));
1215    VM_BUG_ON(!page_count(page));
1216
1217#ifdef CONFIG_KMEMCHECK
1218    /*
1219     * Split shadow pages too, because free(page[0]) would
1220     * otherwise free the whole shadow.
1221     */
1222    if (kmemcheck_page_is_tracked(page))
1223        split_page(virt_to_page(page[0].shadow), order);
1224#endif
1225
1226    for (i = 1; i < (1 << order); i++)
1227        set_page_refcounted(page + i);
1228}
1229
1230/*
1231 * Similar to split_page except the page is already free. As this is only
1232 * being used for migration, the migratetype of the block also changes.
1233 * As this is called with interrupts disabled, the caller is responsible
1234 * for calling arch_alloc_page() and kernel_map_page() after interrupts
1235 * are enabled.
1236 *
1237 * Note: this is probably too low level an operation for use in drivers.
1238 * Please consult with lkml before using this in your driver.
1239 */
1240int split_free_page(struct page *page)
1241{
1242    unsigned int order;
1243    unsigned long watermark;
1244    struct zone *zone;
1245
1246    BUG_ON(!PageBuddy(page));
1247
1248    zone = page_zone(page);
1249    order = page_order(page);
1250
1251    /* Obey watermarks as if the page was being allocated */
1252    watermark = low_wmark_pages(zone) + (1 << order);
1253    if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
1254        return 0;
1255
1256    /* Remove page from free list */
1257    list_del(&page->lru);
1258    zone->free_area[order].nr_free--;
1259    rmv_page_order(page);
1260    __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order));
1261
1262    /* Split into individual pages */
1263    set_page_refcounted(page);
1264    split_page(page, order);
1265
1266    if (order >= pageblock_order - 1) {
1267        struct page *endpage = page + (1 << order) - 1;
1268        for (; page < endpage; page += pageblock_nr_pages)
1269            set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1270    }
1271
1272    return 1 << order;
1273}
1274
1275/*
1276 * Really, prep_compound_page() should be called from __rmqueue_bulk(). But
1277 * we cheat by calling it from here, in the order > 0 path. Saves a branch
1278 * or two.
1279 */
1280static inline
1281struct page *buffered_rmqueue(struct zone *preferred_zone,
1282            struct zone *zone, int order, gfp_t gfp_flags,
1283            int migratetype)
1284{
1285    unsigned long flags;
1286    struct page *page;
1287    int cold = !!(gfp_flags & __GFP_COLD);
1288
1289again:
1290    if (likely(order == 0)) {
1291        struct per_cpu_pages *pcp;
1292        struct list_head *list;
1293
1294        local_irq_save(flags);
1295        pcp = &this_cpu_ptr(zone->pageset)->pcp;
1296        list = &pcp->lists[migratetype];
1297        if (list_empty(list)) {
1298            pcp->count += rmqueue_bulk(zone, 0,
1299                    pcp->batch, list,
1300                    migratetype, cold);
1301            if (unlikely(list_empty(list)))
1302                goto failed;
1303        }
1304
1305        if (cold)
1306            page = list_entry(list->prev, struct page, lru);
1307        else
1308            page = list_entry(list->next, struct page, lru);
1309
1310        list_del(&page->lru);
1311        pcp->count--;
1312    } else {
1313        if (unlikely(gfp_flags & __GFP_NOFAIL)) {
1314            /*
1315             * __GFP_NOFAIL is not to be used in new code.
1316             *
1317             * All __GFP_NOFAIL callers should be fixed so that they
1318             * properly detect and handle allocation failures.
1319             *
1320             * We most definitely don't want callers attempting to
1321             * allocate greater than order-1 page units with
1322             * __GFP_NOFAIL.
1323             */
1324            WARN_ON_ONCE(order > 1);
1325        }
1326        spin_lock_irqsave(&zone->lock, flags);
1327        page = __rmqueue(zone, order, migratetype);
1328        spin_unlock(&zone->lock);
1329        if (!page)
1330            goto failed;
1331        __mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
1332    }
1333
1334    __count_zone_vm_events(PGALLOC, zone, 1 << order);
1335    zone_statistics(preferred_zone, zone);
1336    local_irq_restore(flags);
1337
1338    VM_BUG_ON(bad_range(zone, page));
1339    if (prep_new_page(page, order, gfp_flags))
1340        goto again;
1341    return page;
1342
1343failed:
1344    local_irq_restore(flags);
1345    return NULL;
1346}
1347
1348/* The ALLOC_WMARK bits are used as an index to zone->watermark */
1349#define ALLOC_WMARK_MIN WMARK_MIN
1350#define ALLOC_WMARK_LOW WMARK_LOW
1351#define ALLOC_WMARK_HIGH WMARK_HIGH
1352#define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */
1353
1354/* Mask to get the watermark bits */
1355#define ALLOC_WMARK_MASK (ALLOC_NO_WATERMARKS-1)
1356
1357#define ALLOC_HARDER 0x10 /* try to alloc harder */
1358#define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
1359#define ALLOC_CPUSET 0x40 /* check for correct cpuset */
1360
1361#ifdef CONFIG_FAIL_PAGE_ALLOC
1362
1363static struct fail_page_alloc_attr {
1364    struct fault_attr attr;
1365
1366    u32 ignore_gfp_highmem;
1367    u32 ignore_gfp_wait;
1368    u32 min_order;
1369
1370#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1371
1372    struct dentry *ignore_gfp_highmem_file;
1373    struct dentry *ignore_gfp_wait_file;
1374    struct dentry *min_order_file;
1375
1376#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1377
1378} fail_page_alloc = {
1379    .attr = FAULT_ATTR_INITIALIZER,
1380    .ignore_gfp_wait = 1,
1381    .ignore_gfp_highmem = 1,
1382    .min_order = 1,
1383};
1384
1385static int __init setup_fail_page_alloc(char *str)
1386{
1387    return setup_fault_attr(&fail_page_alloc.attr, str);
1388}
1389__setup("fail_page_alloc=", setup_fail_page_alloc);
1390
1391static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1392{
1393    if (order < fail_page_alloc.min_order)
1394        return 0;
1395    if (gfp_mask & __GFP_NOFAIL)
1396        return 0;
1397    if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1398        return 0;
1399    if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1400        return 0;
1401
1402    return should_fail(&fail_page_alloc.attr, 1 << order);
1403}
1404
1405#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1406
1407static int __init fail_page_alloc_debugfs(void)
1408{
1409    mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1410    struct dentry *dir;
1411    int err;
1412
1413    err = init_fault_attr_dentries(&fail_page_alloc.attr,
1414                       "fail_page_alloc");
1415    if (err)
1416        return err;
1417    dir = fail_page_alloc.attr.dentries.dir;
1418
1419    fail_page_alloc.ignore_gfp_wait_file =
1420        debugfs_create_bool("ignore-gfp-wait", mode, dir,
1421                      &fail_page_alloc.ignore_gfp_wait);
1422
1423    fail_page_alloc.ignore_gfp_highmem_file =
1424        debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1425                      &fail_page_alloc.ignore_gfp_highmem);
1426    fail_page_alloc.min_order_file =
1427        debugfs_create_u32("min-order", mode, dir,
1428                   &fail_page_alloc.min_order);
1429
1430    if (!fail_page_alloc.ignore_gfp_wait_file ||
1431            !fail_page_alloc.ignore_gfp_highmem_file ||
1432            !fail_page_alloc.min_order_file) {
1433        err = -ENOMEM;
1434        debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
1435        debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
1436        debugfs_remove(fail_page_alloc.min_order_file);
1437        cleanup_fault_attr_dentries(&fail_page_alloc.attr);
1438    }
1439
1440    return err;
1441}
1442
1443late_initcall(fail_page_alloc_debugfs);
1444
1445#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1446
1447#else /* CONFIG_FAIL_PAGE_ALLOC */
1448
1449static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1450{
1451    return 0;
1452}
1453
1454#endif /* CONFIG_FAIL_PAGE_ALLOC */
1455
1456/*
1457 * Return 1 if free pages are above 'mark'. This takes into account the order
1458 * of the allocation.
1459 */
1460int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1461              int classzone_idx, int alloc_flags)
1462{
1463    /* free_pages my go negative - that's OK */
1464    long min = mark;
1465    long free_pages = zone_nr_free_pages(z) - (1 << order) + 1;
1466    int o;
1467
1468    if (alloc_flags & ALLOC_HIGH)
1469        min -= min / 2;
1470    if (alloc_flags & ALLOC_HARDER)
1471        min -= min / 4;
1472
1473    if (free_pages <= min + z->lowmem_reserve[classzone_idx])
1474        return 0;
1475    for (o = 0; o < order; o++) {
1476        /* At the next order, this order's pages become unavailable */
1477        free_pages -= z->free_area[o].nr_free << o;
1478
1479        /* Require fewer higher order pages to be free */
1480        min >>= 1;
1481
1482        if (free_pages <= min)
1483            return 0;
1484    }
1485    return 1;
1486}
1487
1488#ifdef CONFIG_NUMA
1489/*
1490 * zlc_setup - Setup for "zonelist cache". Uses cached zone data to
1491 * skip over zones that are not allowed by the cpuset, or that have
1492 * been recently (in last second) found to be nearly full. See further
1493 * comments in mmzone.h. Reduces cache footprint of zonelist scans
1494 * that have to skip over a lot of full or unallowed zones.
1495 *
1496 * If the zonelist cache is present in the passed in zonelist, then
1497 * returns a pointer to the allowed node mask (either the current
1498 * tasks mems_allowed, or node_states[N_HIGH_MEMORY].)
1499 *
1500 * If the zonelist cache is not available for this zonelist, does
1501 * nothing and returns NULL.
1502 *
1503 * If the fullzones BITMAP in the zonelist cache is stale (more than
1504 * a second since last zap'd) then we zap it out (clear its bits.)
1505 *
1506 * We hold off even calling zlc_setup, until after we've checked the
1507 * first zone in the zonelist, on the theory that most allocations will
1508 * be satisfied from that first zone, so best to examine that zone as
1509 * quickly as we can.
1510 */
1511static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1512{
1513    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1514    nodemask_t *allowednodes; /* zonelist_cache approximation */
1515
1516    zlc = zonelist->zlcache_ptr;
1517    if (!zlc)
1518        return NULL;
1519
1520    if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1521        bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1522        zlc->last_full_zap = jiffies;
1523    }
1524
1525    allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1526                    &cpuset_current_mems_allowed :
1527                    &node_states[N_HIGH_MEMORY];
1528    return allowednodes;
1529}
1530
1531/*
1532 * Given 'z' scanning a zonelist, run a couple of quick checks to see
1533 * if it is worth looking at further for free memory:
1534 * 1) Check that the zone isn't thought to be full (doesn't have its
1535 * bit set in the zonelist_cache fullzones BITMAP).
1536 * 2) Check that the zones node (obtained from the zonelist_cache
1537 * z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1538 * Return true (non-zero) if zone is worth looking at further, or
1539 * else return false (zero) if it is not.
1540 *
1541 * This check -ignores- the distinction between various watermarks,
1542 * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ... If a zone is
1543 * found to be full for any variation of these watermarks, it will
1544 * be considered full for up to one second by all requests, unless
1545 * we are so low on memory on all allowed nodes that we are forced
1546 * into the second scan of the zonelist.
1547 *
1548 * In the second scan we ignore this zonelist cache and exactly
1549 * apply the watermarks to all zones, even it is slower to do so.
1550 * We are low on memory in the second scan, and should leave no stone
1551 * unturned looking for a free page.
1552 */
1553static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1554                        nodemask_t *allowednodes)
1555{
1556    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1557    int i; /* index of *z in zonelist zones */
1558    int n; /* node that zone *z is on */
1559
1560    zlc = zonelist->zlcache_ptr;
1561    if (!zlc)
1562        return 1;
1563
1564    i = z - zonelist->_zonerefs;
1565    n = zlc->z_to_n[i];
1566
1567    /* This zone is worth trying if it is allowed but not full */
1568    return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1569}
1570
1571/*
1572 * Given 'z' scanning a zonelist, set the corresponding bit in
1573 * zlc->fullzones, so that subsequent attempts to allocate a page
1574 * from that zone don't waste time re-examining it.
1575 */
1576static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1577{
1578    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1579    int i; /* index of *z in zonelist zones */
1580
1581    zlc = zonelist->zlcache_ptr;
1582    if (!zlc)
1583        return;
1584
1585    i = z - zonelist->_zonerefs;
1586
1587    set_bit(i, zlc->fullzones);
1588}
1589
1590#else /* CONFIG_NUMA */
1591
1592static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1593{
1594    return NULL;
1595}
1596
1597static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1598                nodemask_t *allowednodes)
1599{
1600    return 1;
1601}
1602
1603static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1604{
1605}
1606#endif /* CONFIG_NUMA */
1607
1608/*
1609 * get_page_from_freelist goes through the zonelist trying to allocate
1610 * a page.
1611 */
1612static struct page *
1613get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1614        struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
1615        struct zone *preferred_zone, int migratetype)
1616{
1617    struct zoneref *z;
1618    struct page *page = NULL;
1619    int classzone_idx;
1620    struct zone *zone;
1621    nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1622    int zlc_active = 0; /* set if using zonelist_cache */
1623    int did_zlc_setup = 0; /* just call zlc_setup() one time */
1624
1625    classzone_idx = zone_idx(preferred_zone);
1626zonelist_scan:
1627    /*
1628     * Scan zonelist, looking for a zone with enough free.
1629     * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1630     */
1631    for_each_zone_zonelist_nodemask(zone, z, zonelist,
1632                        high_zoneidx, nodemask) {
1633        if (NUMA_BUILD && zlc_active &&
1634            !zlc_zone_worth_trying(zonelist, z, allowednodes))
1635                continue;
1636        if ((alloc_flags & ALLOC_CPUSET) &&
1637            !cpuset_zone_allowed_softwall(zone, gfp_mask))
1638                goto try_next_zone;
1639
1640        BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
1641        if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
1642            unsigned long mark;
1643            int ret;
1644
1645            mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
1646            if (zone_watermark_ok(zone, order, mark,
1647                    classzone_idx, alloc_flags))
1648                goto try_this_zone;
1649
1650            if (zone_reclaim_mode == 0)
1651                goto this_zone_full;
1652
1653            ret = zone_reclaim(zone, gfp_mask, order);
1654            switch (ret) {
1655            case ZONE_RECLAIM_NOSCAN:
1656                /* did not scan */
1657                goto try_next_zone;
1658            case ZONE_RECLAIM_FULL:
1659                /* scanned but unreclaimable */
1660                goto this_zone_full;
1661            default:
1662                /* did we reclaim enough */
1663                if (!zone_watermark_ok(zone, order, mark,
1664                        classzone_idx, alloc_flags))
1665                    goto this_zone_full;
1666            }
1667        }
1668
1669try_this_zone:
1670        page = buffered_rmqueue(preferred_zone, zone, order,
1671                        gfp_mask, migratetype);
1672        if (page)
1673            break;
1674this_zone_full:
1675        if (NUMA_BUILD)
1676            zlc_mark_zone_full(zonelist, z);
1677try_next_zone:
1678        if (NUMA_BUILD && !did_zlc_setup && nr_online_nodes > 1) {
1679            /*
1680             * we do zlc_setup after the first zone is tried but only
1681             * if there are multiple nodes make it worthwhile
1682             */
1683            allowednodes = zlc_setup(zonelist, alloc_flags);
1684            zlc_active = 1;
1685            did_zlc_setup = 1;
1686        }
1687    }
1688
1689    if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
1690        /* Disable zlc cache for second zonelist scan */
1691        zlc_active = 0;
1692        goto zonelist_scan;
1693    }
1694    return page;
1695}
1696
1697static inline int
1698should_alloc_retry(gfp_t gfp_mask, unsigned int order,
1699                unsigned long pages_reclaimed)
1700{
1701    /* Do not loop if specifically requested */
1702    if (gfp_mask & __GFP_NORETRY)
1703        return 0;
1704
1705    /*
1706     * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
1707     * means __GFP_NOFAIL, but that may not be true in other
1708     * implementations.
1709     */
1710    if (order <= PAGE_ALLOC_COSTLY_ORDER)
1711        return 1;
1712
1713    /*
1714     * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
1715     * specified, then we retry until we no longer reclaim any pages
1716     * (above), or we've reclaimed an order of pages at least as
1717     * large as the allocation's order. In both cases, if the
1718     * allocation still fails, we stop retrying.
1719     */
1720    if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
1721        return 1;
1722
1723    /*
1724     * Don't let big-order allocations loop unless the caller
1725     * explicitly requests that.
1726     */
1727    if (gfp_mask & __GFP_NOFAIL)
1728        return 1;
1729
1730    return 0;
1731}
1732
1733static inline struct page *
1734__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
1735    struct zonelist *zonelist, enum zone_type high_zoneidx,
1736    nodemask_t *nodemask, struct zone *preferred_zone,
1737    int migratetype)
1738{
1739    struct page *page;
1740
1741    /* Acquire the OOM killer lock for the zones in zonelist */
1742    if (!try_set_zonelist_oom(zonelist, gfp_mask)) {
1743        schedule_timeout_uninterruptible(1);
1744        return NULL;
1745    }
1746
1747    /*
1748     * Go through the zonelist yet one more time, keep very high watermark
1749     * here, this is only to catch a parallel oom killing, we must fail if
1750     * we're still under heavy pressure.
1751     */
1752    page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
1753        order, zonelist, high_zoneidx,
1754        ALLOC_WMARK_HIGH|ALLOC_CPUSET,
1755        preferred_zone, migratetype);
1756    if (page)
1757        goto out;
1758
1759    if (!(gfp_mask & __GFP_NOFAIL)) {
1760        /* The OOM killer will not help higher order allocs */
1761        if (order > PAGE_ALLOC_COSTLY_ORDER)
1762            goto out;
1763        /* The OOM killer does not needlessly kill tasks for lowmem */
1764        if (high_zoneidx < ZONE_NORMAL)
1765            goto out;
1766        /*
1767         * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
1768         * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
1769         * The caller should handle page allocation failure by itself if
1770         * it specifies __GFP_THISNODE.
1771         * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
1772         */
1773        if (gfp_mask & __GFP_THISNODE)
1774            goto out;
1775    }
1776    /* Exhausted what can be done so it's blamo time */
1777    out_of_memory(zonelist, gfp_mask, order, nodemask);
1778
1779out:
1780    clear_zonelist_oom(zonelist, gfp_mask);
1781    return page;
1782}
1783
1784#ifdef CONFIG_COMPACTION
1785/* Try memory compaction for high-order allocations before reclaim */
1786static struct page *
1787__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
1788    struct zonelist *zonelist, enum zone_type high_zoneidx,
1789    nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1790    int migratetype, unsigned long *did_some_progress)
1791{
1792    struct page *page;
1793
1794    if (!order || compaction_deferred(preferred_zone))
1795        return NULL;
1796
1797    *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
1798                                nodemask);
1799    if (*did_some_progress != COMPACT_SKIPPED) {
1800
1801        /* Page migration frees to the PCP lists but we want merging */
1802        drain_pages(get_cpu());
1803        put_cpu();
1804
1805        page = get_page_from_freelist(gfp_mask, nodemask,
1806                order, zonelist, high_zoneidx,
1807                alloc_flags, preferred_zone,
1808                migratetype);
1809        if (page) {
1810            preferred_zone->compact_considered = 0;
1811            preferred_zone->compact_defer_shift = 0;
1812            count_vm_event(COMPACTSUCCESS);
1813            return page;
1814        }
1815
1816        /*
1817         * It's bad if compaction run occurs and fails.
1818         * The most likely reason is that pages exist,
1819         * but not enough to satisfy watermarks.
1820         */
1821        count_vm_event(COMPACTFAIL);
1822        defer_compaction(preferred_zone);
1823
1824        cond_resched();
1825    }
1826
1827    return NULL;
1828}
1829#else
1830static inline struct page *
1831__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
1832    struct zonelist *zonelist, enum zone_type high_zoneidx,
1833    nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1834    int migratetype, unsigned long *did_some_progress)
1835{
1836    return NULL;
1837}
1838#endif /* CONFIG_COMPACTION */
1839
1840/* The really slow allocator path where we enter direct reclaim */
1841static inline struct page *
1842__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
1843    struct zonelist *zonelist, enum zone_type high_zoneidx,
1844    nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1845    int migratetype, unsigned long *did_some_progress)
1846{
1847    struct page *page = NULL;
1848    struct reclaim_state reclaim_state;
1849    struct task_struct *p = current;
1850    bool drained = false;
1851
1852    cond_resched();
1853
1854    /* We now go into synchronous reclaim */
1855    cpuset_memory_pressure_bump();
1856    p->flags |= PF_MEMALLOC;
1857    lockdep_set_current_reclaim_state(gfp_mask);
1858    reclaim_state.reclaimed_slab = 0;
1859    p->reclaim_state = &reclaim_state;
1860
1861    *did_some_progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
1862
1863    p->reclaim_state = NULL;
1864    lockdep_clear_current_reclaim_state();
1865    p->flags &= ~PF_MEMALLOC;
1866
1867    cond_resched();
1868
1869    if (unlikely(!(*did_some_progress)))
1870        return NULL;
1871
1872retry:
1873    page = get_page_from_freelist(gfp_mask, nodemask, order,
1874                    zonelist, high_zoneidx,
1875                    alloc_flags, preferred_zone,
1876                    migratetype);
1877
1878    /*
1879     * If an allocation failed after direct reclaim, it could be because
1880     * pages are pinned on the per-cpu lists. Drain them and try again
1881     */
1882    if (!page && !drained) {
1883        drain_all_pages();
1884        drained = true;
1885        goto retry;
1886    }
1887
1888    return page;
1889}
1890
1891/*
1892 * This is called in the allocator slow-path if the allocation request is of
1893 * sufficient urgency to ignore watermarks and take other desperate measures
1894 */
1895static inline struct page *
1896__alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
1897    struct zonelist *zonelist, enum zone_type high_zoneidx,
1898    nodemask_t *nodemask, struct zone *preferred_zone,
1899    int migratetype)
1900{
1901    struct page *page;
1902
1903    do {
1904        page = get_page_from_freelist(gfp_mask, nodemask, order,
1905            zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
1906            preferred_zone, migratetype);
1907
1908        if (!page && gfp_mask & __GFP_NOFAIL)
1909            congestion_wait(BLK_RW_ASYNC, HZ/50);
1910    } while (!page && (gfp_mask & __GFP_NOFAIL));
1911
1912    return page;
1913}
1914
1915static inline
1916void wake_all_kswapd(unsigned int order, struct zonelist *zonelist,
1917                        enum zone_type high_zoneidx)
1918{
1919    struct zoneref *z;
1920    struct zone *zone;
1921
1922    for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
1923        wakeup_kswapd(zone, order);
1924}
1925
1926static inline int
1927gfp_to_alloc_flags(gfp_t gfp_mask)
1928{
1929    struct task_struct *p = current;
1930    int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
1931    const gfp_t wait = gfp_mask & __GFP_WAIT;
1932
1933    /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
1934    BUILD_BUG_ON(__GFP_HIGH != ALLOC_HIGH);
1935
1936    /*
1937     * The caller may dip into page reserves a bit more if the caller
1938     * cannot run direct reclaim, or if the caller has realtime scheduling
1939     * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
1940     * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
1941     */
1942    alloc_flags |= (gfp_mask & __GFP_HIGH);
1943
1944    if (!wait) {
1945        alloc_flags |= ALLOC_HARDER;
1946        /*
1947         * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
1948         * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1949         */
1950        alloc_flags &= ~ALLOC_CPUSET;
1951    } else if (unlikely(rt_task(p)) && !in_interrupt())
1952        alloc_flags |= ALLOC_HARDER;
1953
1954    if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
1955        if (!in_interrupt() &&
1956            ((p->flags & PF_MEMALLOC) ||
1957             unlikely(test_thread_flag(TIF_MEMDIE))))
1958            alloc_flags |= ALLOC_NO_WATERMARKS;
1959    }
1960
1961    return alloc_flags;
1962}
1963
1964static inline struct page *
1965__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
1966    struct zonelist *zonelist, enum zone_type high_zoneidx,
1967    nodemask_t *nodemask, struct zone *preferred_zone,
1968    int migratetype)
1969{
1970    const gfp_t wait = gfp_mask & __GFP_WAIT;
1971    struct page *page = NULL;
1972    int alloc_flags;
1973    unsigned long pages_reclaimed = 0;
1974    unsigned long did_some_progress;
1975    struct task_struct *p = current;
1976
1977    /*
1978     * In the slowpath, we sanity check order to avoid ever trying to
1979     * reclaim >= MAX_ORDER areas which will never succeed. Callers may
1980     * be using allocators in order of preference for an area that is
1981     * too large.
1982     */
1983    if (order >= MAX_ORDER) {
1984        WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
1985        return NULL;
1986    }
1987
1988    /*
1989     * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
1990     * __GFP_NOWARN set) should not cause reclaim since the subsystem
1991     * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
1992     * using a larger set of nodes after it has established that the
1993     * allowed per node queues are empty and that nodes are
1994     * over allocated.
1995     */
1996    if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
1997        goto nopage;
1998
1999restart:
2000    wake_all_kswapd(order, zonelist, high_zoneidx);
2001
2002    /*
2003     * OK, we're below the kswapd watermark and have kicked background
2004     * reclaim. Now things get more complex, so set up alloc_flags according
2005     * to how we want to proceed.
2006     */
2007    alloc_flags = gfp_to_alloc_flags(gfp_mask);
2008
2009    /* This is the last chance, in general, before the goto nopage. */
2010    page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
2011            high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
2012            preferred_zone, migratetype);
2013    if (page)
2014        goto got_pg;
2015
2016rebalance:
2017    /* Allocate without watermarks if the context allows */
2018    if (alloc_flags & ALLOC_NO_WATERMARKS) {
2019        page = __alloc_pages_high_priority(gfp_mask, order,
2020                zonelist, high_zoneidx, nodemask,
2021                preferred_zone, migratetype);
2022        if (page)
2023            goto got_pg;
2024    }
2025
2026    /* Atomic allocations - we can't balance anything */
2027    if (!wait)
2028        goto nopage;
2029
2030    /* Avoid recursion of direct reclaim */
2031    if (p->flags & PF_MEMALLOC)
2032        goto nopage;
2033
2034    /* Avoid allocations with no watermarks from looping endlessly */
2035    if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
2036        goto nopage;
2037
2038    /* Try direct compaction */
2039    page = __alloc_pages_direct_compact(gfp_mask, order,
2040                    zonelist, high_zoneidx,
2041                    nodemask,
2042                    alloc_flags, preferred_zone,
2043                    migratetype, &did_some_progress);
2044    if (page)
2045        goto got_pg;
2046
2047    /* Try direct reclaim and then allocating */
2048    page = __alloc_pages_direct_reclaim(gfp_mask, order,
2049                    zonelist, high_zoneidx,
2050                    nodemask,
2051                    alloc_flags, preferred_zone,
2052                    migratetype, &did_some_progress);
2053    if (page)
2054        goto got_pg;
2055
2056    /*
2057     * If we failed to make any progress reclaiming, then we are
2058     * running out of options and have to consider going OOM
2059     */
2060    if (!did_some_progress) {
2061        if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
2062            if (oom_killer_disabled)
2063                goto nopage;
2064            page = __alloc_pages_may_oom(gfp_mask, order,
2065                    zonelist, high_zoneidx,
2066                    nodemask, preferred_zone,
2067                    migratetype);
2068            if (page)
2069                goto got_pg;
2070
2071            if (!(gfp_mask & __GFP_NOFAIL)) {
2072                /*
2073                 * The oom killer is not called for high-order
2074                 * allocations that may fail, so if no progress
2075                 * is being made, there are no other options and
2076                 * retrying is unlikely to help.
2077                 */
2078                if (order > PAGE_ALLOC_COSTLY_ORDER)
2079                    goto nopage;
2080                /*
2081                 * The oom killer is not called for lowmem
2082                 * allocations to prevent needlessly killing
2083                 * innocent tasks.
2084                 */
2085                if (high_zoneidx < ZONE_NORMAL)
2086                    goto nopage;
2087            }
2088
2089            goto restart;
2090        }
2091    }
2092
2093    /* Check if we should retry the allocation */
2094    pages_reclaimed += did_some_progress;
2095    if (should_alloc_retry(gfp_mask, order, pages_reclaimed)) {
2096        /* Wait for some write requests to complete then retry */
2097        congestion_wait(BLK_RW_ASYNC, HZ/50);
2098        goto rebalance;
2099    }
2100
2101nopage:
2102    if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
2103        printk(KERN_WARNING "%s: page allocation failure."
2104            " order:%d, mode:0x%x\n",
2105            p->comm, order, gfp_mask);
2106        dump_stack();
2107        show_mem();
2108    }
2109    return page;
2110got_pg:
2111    if (kmemcheck_enabled)
2112        kmemcheck_pagealloc_alloc(page, order, gfp_mask);
2113    return page;
2114
2115}
2116
2117/*
2118 * This is the 'heart' of the zoned buddy allocator.
2119 */
2120struct page *
2121__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
2122            struct zonelist *zonelist, nodemask_t *nodemask)
2123{
2124    enum zone_type high_zoneidx = gfp_zone(gfp_mask);
2125    struct zone *preferred_zone;
2126    struct page *page;
2127    int migratetype = allocflags_to_migratetype(gfp_mask);
2128
2129    gfp_mask &= gfp_allowed_mask;
2130
2131    lockdep_trace_alloc(gfp_mask);
2132
2133    might_sleep_if(gfp_mask & __GFP_WAIT);
2134
2135    if (should_fail_alloc_page(gfp_mask, order))
2136        return NULL;
2137
2138    /*
2139     * Check the zones suitable for the gfp_mask contain at least one
2140     * valid zone. It's possible to have an empty zonelist as a result
2141     * of GFP_THISNODE and a memoryless node
2142     */
2143    if (unlikely(!zonelist->_zonerefs->zone))
2144        return NULL;
2145
2146    get_mems_allowed();
2147    /* The preferred zone is used for statistics later */
2148    first_zones_zonelist(zonelist, high_zoneidx, nodemask, &preferred_zone);
2149    if (!preferred_zone) {
2150        put_mems_allowed();
2151        return NULL;
2152    }
2153
2154    /* First allocation attempt */
2155    page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
2156            zonelist, high_zoneidx, ALLOC_WMARK_LOW|ALLOC_CPUSET,
2157            preferred_zone, migratetype);
2158    if (unlikely(!page))
2159        page = __alloc_pages_slowpath(gfp_mask, order,
2160                zonelist, high_zoneidx, nodemask,
2161                preferred_zone, migratetype);
2162    put_mems_allowed();
2163
2164    trace_mm_page_alloc(page, order, gfp_mask, migratetype);
2165    return page;
2166}
2167EXPORT_SYMBOL(__alloc_pages_nodemask);
2168
2169/*
2170 * Common helper functions.
2171 */
2172unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
2173{
2174    struct page *page;
2175
2176    /*
2177     * __get_free_pages() returns a 32-bit address, which cannot represent
2178     * a highmem page
2179     */
2180    VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
2181
2182    page = alloc_pages(gfp_mask, order);
2183    if (!page)
2184        return 0;
2185    return (unsigned long) page_address(page);
2186}
2187EXPORT_SYMBOL(__get_free_pages);
2188
2189unsigned long get_zeroed_page(gfp_t gfp_mask)
2190{
2191    return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
2192}
2193EXPORT_SYMBOL(get_zeroed_page);
2194
2195void __pagevec_free(struct pagevec *pvec)
2196{
2197    int i = pagevec_count(pvec);
2198
2199    while (--i >= 0) {
2200        trace_mm_pagevec_free(pvec->pages[i], pvec->cold);
2201        free_hot_cold_page(pvec->pages[i], pvec->cold);
2202    }
2203}
2204
2205void __free_pages(struct page *page, unsigned int order)
2206{
2207    if (put_page_testzero(page)) {
2208        if (order == 0)
2209            free_hot_cold_page(page, 0);
2210        else
2211            __free_pages_ok(page, order);
2212    }
2213}
2214
2215EXPORT_SYMBOL(__free_pages);
2216
2217void free_pages(unsigned long addr, unsigned int order)
2218{
2219    if (addr != 0) {
2220        VM_BUG_ON(!virt_addr_valid((void *)addr));
2221        __free_pages(virt_to_page((void *)addr), order);
2222    }
2223}
2224
2225EXPORT_SYMBOL(free_pages);
2226
2227/**
2228 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
2229 * @size: the number of bytes to allocate
2230 * @gfp_mask: GFP flags for the allocation
2231 *
2232 * This function is similar to alloc_pages(), except that it allocates the
2233 * minimum number of pages to satisfy the request. alloc_pages() can only
2234 * allocate memory in power-of-two pages.
2235 *
2236 * This function is also limited by MAX_ORDER.
2237 *
2238 * Memory allocated by this function must be released by free_pages_exact().
2239 */
2240void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
2241{
2242    unsigned int order = get_order(size);
2243    unsigned long addr;
2244
2245    addr = __get_free_pages(gfp_mask, order);
2246    if (addr) {
2247        unsigned long alloc_end = addr + (PAGE_SIZE << order);
2248        unsigned long used = addr + PAGE_ALIGN(size);
2249
2250        split_page(virt_to_page((void *)addr), order);
2251        while (used < alloc_end) {
2252            free_page(used);
2253            used += PAGE_SIZE;
2254        }
2255    }
2256
2257    return (void *)addr;
2258}
2259EXPORT_SYMBOL(alloc_pages_exact);
2260
2261/**
2262 * free_pages_exact - release memory allocated via alloc_pages_exact()
2263 * @virt: the value returned by alloc_pages_exact.
2264 * @size: size of allocation, same value as passed to alloc_pages_exact().
2265 *
2266 * Release the memory allocated by a previous call to alloc_pages_exact.
2267 */
2268void free_pages_exact(void *virt, size_t size)
2269{
2270    unsigned long addr = (unsigned long)virt;
2271    unsigned long end = addr + PAGE_ALIGN(size);
2272
2273    while (addr < end) {
2274        free_page(addr);
2275        addr += PAGE_SIZE;
2276    }
2277}
2278EXPORT_SYMBOL(free_pages_exact);
2279
2280static unsigned int nr_free_zone_pages(int offset)
2281{
2282    struct zoneref *z;
2283    struct zone *zone;
2284
2285    /* Just pick one node, since fallback list is circular */
2286    unsigned int sum = 0;
2287
2288    struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
2289
2290    for_each_zone_zonelist(zone, z, zonelist, offset) {
2291        unsigned long size = zone->present_pages;
2292        unsigned long high = high_wmark_pages(zone);
2293        if (size > high)
2294            sum += size - high;
2295    }
2296
2297    return sum;
2298}
2299
2300/*
2301 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
2302 */
2303unsigned int nr_free_buffer_pages(void)
2304{
2305    return nr_free_zone_pages(gfp_zone(GFP_USER));
2306}
2307EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
2308
2309/*
2310 * Amount of free RAM allocatable within all zones
2311 */
2312unsigned int nr_free_pagecache_pages(void)
2313{
2314    return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
2315}
2316
2317static inline void show_node(struct zone *zone)
2318{
2319    if (NUMA_BUILD)
2320        printk("Node %d ", zone_to_nid(zone));
2321}
2322
2323void si_meminfo(struct sysinfo *val)
2324{
2325    val->totalram = totalram_pages;
2326    val->sharedram = 0;
2327    val->freeram = global_page_state(NR_FREE_PAGES);
2328    val->bufferram = nr_blockdev_pages();
2329    val->totalhigh = totalhigh_pages;
2330    val->freehigh = nr_free_highpages();
2331    val->mem_unit = PAGE_SIZE;
2332}
2333
2334EXPORT_SYMBOL(si_meminfo);
2335
2336#ifdef CONFIG_NUMA
2337void si_meminfo_node(struct sysinfo *val, int nid)
2338{
2339    pg_data_t *pgdat = NODE_DATA(nid);
2340
2341    val->totalram = pgdat->node_present_pages;
2342    val->freeram = node_page_state(nid, NR_FREE_PAGES);
2343#ifdef CONFIG_HIGHMEM
2344    val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
2345    val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
2346            NR_FREE_PAGES);
2347#else
2348    val->totalhigh = 0;
2349    val->freehigh = 0;
2350#endif
2351    val->mem_unit = PAGE_SIZE;
2352}
2353#endif
2354
2355#define K(x) ((x) << (PAGE_SHIFT-10))
2356
2357/*
2358 * Show free area list (used inside shift_scroll-lock stuff)
2359 * We also calculate the percentage fragmentation. We do this by counting the
2360 * memory on each free list with the exception of the first item on the list.
2361 */
2362void show_free_areas(void)
2363{
2364    int cpu;
2365    struct zone *zone;
2366
2367    for_each_populated_zone(zone) {
2368        show_node(zone);
2369        printk("%s per-cpu:\n", zone->name);
2370
2371        for_each_online_cpu(cpu) {
2372            struct per_cpu_pageset *pageset;
2373
2374            pageset = per_cpu_ptr(zone->pageset, cpu);
2375
2376            printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
2377                   cpu, pageset->pcp.high,
2378                   pageset->pcp.batch, pageset->pcp.count);
2379        }
2380    }
2381
2382    printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
2383        " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
2384        " unevictable:%lu"
2385        " dirty:%lu writeback:%lu unstable:%lu\n"
2386        " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
2387        " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n",
2388        global_page_state(NR_ACTIVE_ANON),
2389        global_page_state(NR_INACTIVE_ANON),
2390        global_page_state(NR_ISOLATED_ANON),
2391        global_page_state(NR_ACTIVE_FILE),
2392        global_page_state(NR_INACTIVE_FILE),
2393        global_page_state(NR_ISOLATED_FILE),
2394        global_page_state(NR_UNEVICTABLE),
2395        global_page_state(NR_FILE_DIRTY),
2396        global_page_state(NR_WRITEBACK),
2397        global_page_state(NR_UNSTABLE_NFS),
2398        global_page_state(NR_FREE_PAGES),
2399        global_page_state(NR_SLAB_RECLAIMABLE),
2400        global_page_state(NR_SLAB_UNRECLAIMABLE),
2401        global_page_state(NR_FILE_MAPPED),
2402        global_page_state(NR_SHMEM),
2403        global_page_state(NR_PAGETABLE),
2404        global_page_state(NR_BOUNCE));
2405
2406    for_each_populated_zone(zone) {
2407        int i;
2408
2409        show_node(zone);
2410        printk("%s"
2411            " free:%lukB"
2412            " min:%lukB"
2413            " low:%lukB"
2414            " high:%lukB"
2415            " active_anon:%lukB"
2416            " inactive_anon:%lukB"
2417            " active_file:%lukB"
2418            " inactive_file:%lukB"
2419            " unevictable:%lukB"
2420            " isolated(anon):%lukB"
2421            " isolated(file):%lukB"
2422            " present:%lukB"
2423            " mlocked:%lukB"
2424            " dirty:%lukB"
2425            " writeback:%lukB"
2426            " mapped:%lukB"
2427            " shmem:%lukB"
2428            " slab_reclaimable:%lukB"
2429            " slab_unreclaimable:%lukB"
2430            " kernel_stack:%lukB"
2431            " pagetables:%lukB"
2432            " unstable:%lukB"
2433            " bounce:%lukB"
2434            " writeback_tmp:%lukB"
2435            " pages_scanned:%lu"
2436            " all_unreclaimable? %s"
2437            "\n",
2438            zone->name,
2439            K(zone_nr_free_pages(zone)),
2440            K(min_wmark_pages(zone)),
2441            K(low_wmark_pages(zone)),
2442            K(high_wmark_pages(zone)),
2443            K(zone_page_state(zone, NR_ACTIVE_ANON)),
2444            K(zone_page_state(zone, NR_INACTIVE_ANON)),
2445            K(zone_page_state(zone, NR_ACTIVE_FILE)),
2446            K(zone_page_state(zone, NR_INACTIVE_FILE)),
2447            K(zone_page_state(zone, NR_UNEVICTABLE)),
2448            K(zone_page_state(zone, NR_ISOLATED_ANON)),
2449            K(zone_page_state(zone, NR_ISOLATED_FILE)),
2450            K(zone->present_pages),
2451            K(zone_page_state(zone, NR_MLOCK)),
2452            K(zone_page_state(zone, NR_FILE_DIRTY)),
2453            K(zone_page_state(zone, NR_WRITEBACK)),
2454            K(zone_page_state(zone, NR_FILE_MAPPED)),
2455            K(zone_page_state(zone, NR_SHMEM)),
2456            K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
2457            K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
2458            zone_page_state(zone, NR_KERNEL_STACK) *
2459                THREAD_SIZE / 1024,
2460            K(zone_page_state(zone, NR_PAGETABLE)),
2461            K(zone_page_state(zone, NR_UNSTABLE_NFS)),
2462            K(zone_page_state(zone, NR_BOUNCE)),
2463            K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
2464            zone->pages_scanned,
2465            (zone->all_unreclaimable ? "yes" : "no")
2466            );
2467        printk("lowmem_reserve[]:");
2468        for (i = 0; i < MAX_NR_ZONES; i++)
2469            printk(" %lu", zone->lowmem_reserve[i]);
2470        printk("\n");
2471    }
2472
2473    for_each_populated_zone(zone) {
2474         unsigned long nr[MAX_ORDER], flags, order, total = 0;
2475
2476        show_node(zone);
2477        printk("%s: ", zone->name);
2478
2479        spin_lock_irqsave(&zone->lock, flags);
2480        for (order = 0; order < MAX_ORDER; order++) {
2481            nr[order] = zone->free_area[order].nr_free;
2482            total += nr[order] << order;
2483        }
2484        spin_unlock_irqrestore(&zone->lock, flags);
2485        for (order = 0; order < MAX_ORDER; order++)
2486            printk("%lu*%lukB ", nr[order], K(1UL) << order);
2487        printk("= %lukB\n", K(total));
2488    }
2489
2490    printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
2491
2492    show_swap_cache_info();
2493}
2494
2495static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
2496{
2497    zoneref->zone = zone;
2498    zoneref->zone_idx = zone_idx(zone);
2499}
2500
2501/*
2502 * Builds allocation fallback zone lists.
2503 *
2504 * Add all populated zones of a node to the zonelist.
2505 */
2506static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
2507                int nr_zones, enum zone_type zone_type)
2508{
2509    struct zone *zone;
2510
2511    BUG_ON(zone_type >= MAX_NR_ZONES);
2512    zone_type++;
2513
2514    do {
2515        zone_type--;
2516        zone = pgdat->node_zones + zone_type;
2517        if (populated_zone(zone)) {
2518            zoneref_set_zone(zone,
2519                &zonelist->_zonerefs[nr_zones++]);
2520            check_highest_zone(zone_type);
2521        }
2522
2523    } while (zone_type);
2524    return nr_zones;
2525}
2526
2527
2528/*
2529 * zonelist_order:
2530 * 0 = automatic detection of better ordering.
2531 * 1 = order by ([node] distance, -zonetype)
2532 * 2 = order by (-zonetype, [node] distance)
2533 *
2534 * If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
2535 * the same zonelist. So only NUMA can configure this param.
2536 */
2537#define ZONELIST_ORDER_DEFAULT 0
2538#define ZONELIST_ORDER_NODE 1
2539#define ZONELIST_ORDER_ZONE 2
2540
2541/* zonelist order in the kernel.
2542 * set_zonelist_order() will set this to NODE or ZONE.
2543 */
2544static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
2545static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
2546
2547
2548#ifdef CONFIG_NUMA
2549/* The value user specified ....changed by config */
2550static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2551/* string for sysctl */
2552#define NUMA_ZONELIST_ORDER_LEN 16
2553char numa_zonelist_order[16] = "default";
2554
2555/*
2556 * interface for configure zonelist ordering.
2557 * command line option "numa_zonelist_order"
2558 * = "[dD]efault - default, automatic configuration.
2559 * = "[nN]ode - order by node locality, then by zone within node
2560 * = "[zZ]one - order by zone, then by locality within zone
2561 */
2562
2563static int __parse_numa_zonelist_order(char *s)
2564{
2565    if (*s == 'd' || *s == 'D') {
2566        user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2567    } else if (*s == 'n' || *s == 'N') {
2568        user_zonelist_order = ZONELIST_ORDER_NODE;
2569    } else if (*s == 'z' || *s == 'Z') {
2570        user_zonelist_order = ZONELIST_ORDER_ZONE;
2571    } else {
2572        printk(KERN_WARNING
2573            "Ignoring invalid numa_zonelist_order value: "
2574            "%s\n", s);
2575        return -EINVAL;
2576    }
2577    return 0;
2578}
2579
2580static __init int setup_numa_zonelist_order(char *s)
2581{
2582    if (s)
2583        return __parse_numa_zonelist_order(s);
2584    return 0;
2585}
2586early_param("numa_zonelist_order", setup_numa_zonelist_order);
2587
2588/*
2589 * sysctl handler for numa_zonelist_order
2590 */
2591int numa_zonelist_order_handler(ctl_table *table, int write,
2592        void __user *buffer, size_t *length,
2593        loff_t *ppos)
2594{
2595    char saved_string[NUMA_ZONELIST_ORDER_LEN];
2596    int ret;
2597    static DEFINE_MUTEX(zl_order_mutex);
2598
2599    mutex_lock(&zl_order_mutex);
2600    if (write)
2601        strcpy(saved_string, (char*)table->data);
2602    ret = proc_dostring(table, write, buffer, length, ppos);
2603    if (ret)
2604        goto out;
2605    if (write) {
2606        int oldval = user_zonelist_order;
2607        if (__parse_numa_zonelist_order((char*)table->data)) {
2608            /*
2609             * bogus value. restore saved string
2610             */
2611            strncpy((char*)table->data, saved_string,
2612                NUMA_ZONELIST_ORDER_LEN);
2613            user_zonelist_order = oldval;
2614        } else if (oldval != user_zonelist_order) {
2615            mutex_lock(&zonelists_mutex);
2616            build_all_zonelists(NULL);
2617            mutex_unlock(&zonelists_mutex);
2618        }
2619    }
2620out:
2621    mutex_unlock(&zl_order_mutex);
2622    return ret;
2623}
2624
2625
2626#define MAX_NODE_LOAD (nr_online_nodes)
2627static int node_load[MAX_NUMNODES];
2628
2629/**
2630 * find_next_best_node - find the next node that should appear in a given node's fallback list
2631 * @node: node whose fallback list we're appending
2632 * @used_node_mask: nodemask_t of already used nodes
2633 *
2634 * We use a number of factors to determine which is the next node that should
2635 * appear on a given node's fallback list. The node should not have appeared
2636 * already in @node's fallback list, and it should be the next closest node
2637 * according to the distance array (which contains arbitrary distance values
2638 * from each node to each node in the system), and should also prefer nodes
2639 * with no CPUs, since presumably they'll have very little allocation pressure
2640 * on them otherwise.
2641 * It returns -1 if no node is found.
2642 */
2643static int find_next_best_node(int node, nodemask_t *used_node_mask)
2644{
2645    int n, val;
2646    int min_val = INT_MAX;
2647    int best_node = -1;
2648    const struct cpumask *tmp = cpumask_of_node(0);
2649
2650    /* Use the local node if we haven't already */
2651    if (!node_isset(node, *used_node_mask)) {
2652        node_set(node, *used_node_mask);
2653        return node;
2654    }
2655
2656    for_each_node_state(n, N_HIGH_MEMORY) {
2657
2658        /* Don't want a node to appear more than once */
2659        if (node_isset(n, *used_node_mask))
2660            continue;
2661
2662        /* Use the distance array to find the distance */
2663        val = node_distance(node, n);
2664
2665        /* Penalize nodes under us ("prefer the next node") */
2666        val += (n < node);
2667
2668        /* Give preference to headless and unused nodes */
2669        tmp = cpumask_of_node(n);
2670        if (!cpumask_empty(tmp))
2671            val += PENALTY_FOR_NODE_WITH_CPUS;
2672
2673        /* Slight preference for less loaded node */
2674        val *= (MAX_NODE_LOAD*MAX_NUMNODES);
2675        val += node_load[n];
2676
2677        if (val < min_val) {
2678            min_val = val;
2679            best_node = n;
2680        }
2681    }
2682
2683    if (best_node >= 0)
2684        node_set(best_node, *used_node_mask);
2685
2686    return best_node;
2687}
2688
2689
2690/*
2691 * Build zonelists ordered by node and zones within node.
2692 * This results in maximum locality--normal zone overflows into local
2693 * DMA zone, if any--but risks exhausting DMA zone.
2694 */
2695static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
2696{
2697    int j;
2698    struct zonelist *zonelist;
2699
2700    zonelist = &pgdat->node_zonelists[0];
2701    for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
2702        ;
2703    j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2704                            MAX_NR_ZONES - 1);
2705    zonelist->_zonerefs[j].zone = NULL;
2706    zonelist->_zonerefs[j].zone_idx = 0;
2707}
2708
2709/*
2710 * Build gfp_thisnode zonelists
2711 */
2712static void build_thisnode_zonelists(pg_data_t *pgdat)
2713{
2714    int j;
2715    struct zonelist *zonelist;
2716
2717    zonelist = &pgdat->node_zonelists[1];
2718    j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
2719    zonelist->_zonerefs[j].zone = NULL;
2720    zonelist->_zonerefs[j].zone_idx = 0;
2721}
2722
2723/*
2724 * Build zonelists ordered by zone and nodes within zones.
2725 * This results in conserving DMA zone[s] until all Normal memory is
2726 * exhausted, but results in overflowing to remote node while memory
2727 * may still exist in local DMA zone.
2728 */
2729static int node_order[MAX_NUMNODES];
2730
2731static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
2732{
2733    int pos, j, node;
2734    int zone_type; /* needs to be signed */
2735    struct zone *z;
2736    struct zonelist *zonelist;
2737
2738    zonelist = &pgdat->node_zonelists[0];
2739    pos = 0;
2740    for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
2741        for (j = 0; j < nr_nodes; j++) {
2742            node = node_order[j];
2743            z = &NODE_DATA(node)->node_zones[zone_type];
2744            if (populated_zone(z)) {
2745                zoneref_set_zone(z,
2746                    &zonelist->_zonerefs[pos++]);
2747                check_highest_zone(zone_type);
2748            }
2749        }
2750    }
2751    zonelist->_zonerefs[pos].zone = NULL;
2752    zonelist->_zonerefs[pos].zone_idx = 0;
2753}
2754
2755static int default_zonelist_order(void)
2756{
2757    int nid, zone_type;
2758    unsigned long low_kmem_size,total_size;
2759    struct zone *z;
2760    int average_size;
2761    /*
2762         * ZONE_DMA and ZONE_DMA32 can be very small area in the system.
2763     * If they are really small and used heavily, the system can fall
2764     * into OOM very easily.
2765     * This function detect ZONE_DMA/DMA32 size and configures zone order.
2766     */
2767    /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
2768    low_kmem_size = 0;
2769    total_size = 0;
2770    for_each_online_node(nid) {
2771        for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
2772            z = &NODE_DATA(nid)->node_zones[zone_type];
2773            if (populated_zone(z)) {
2774                if (zone_type < ZONE_NORMAL)
2775                    low_kmem_size += z->present_pages;
2776                total_size += z->present_pages;
2777            } else if (zone_type == ZONE_NORMAL) {
2778                /*
2779                 * If any node has only lowmem, then node order
2780                 * is preferred to allow kernel allocations
2781                 * locally; otherwise, they can easily infringe
2782                 * on other nodes when there is an abundance of
2783                 * lowmem available to allocate from.
2784                 */
2785                return ZONELIST_ORDER_NODE;
2786            }
2787        }
2788    }
2789    if (!low_kmem_size || /* there are no DMA area. */
2790        low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
2791        return ZONELIST_ORDER_NODE;
2792    /*
2793     * look into each node's config.
2794       * If there is a node whose DMA/DMA32 memory is very big area on
2795      * local memory, NODE_ORDER may be suitable.
2796         */
2797    average_size = total_size /
2798                (nodes_weight(node_states[N_HIGH_MEMORY]) + 1);
2799    for_each_online_node(nid) {
2800        low_kmem_size = 0;
2801        total_size = 0;
2802        for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
2803            z = &NODE_DATA(nid)->node_zones[zone_type];
2804            if (populated_zone(z)) {
2805                if (zone_type < ZONE_NORMAL)
2806                    low_kmem_size += z->present_pages;
2807                total_size += z->present_pages;
2808            }
2809        }
2810        if (low_kmem_size &&
2811            total_size > average_size && /* ignore small node */
2812            low_kmem_size > total_size * 70/100)
2813            return ZONELIST_ORDER_NODE;
2814    }
2815    return ZONELIST_ORDER_ZONE;
2816}
2817
2818static void set_zonelist_order(void)
2819{
2820    if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
2821        current_zonelist_order = default_zonelist_order();
2822    else
2823        current_zonelist_order = user_zonelist_order;
2824}
2825
2826static void build_zonelists(pg_data_t *pgdat)
2827{
2828    int j, node, load;
2829    enum zone_type i;
2830    nodemask_t used_mask;
2831    int local_node, prev_node;
2832    struct zonelist *zonelist;
2833    int order = current_zonelist_order;
2834
2835    /* initialize zonelists */
2836    for (i = 0; i < MAX_ZONELISTS; i++) {
2837        zonelist = pgdat->node_zonelists + i;
2838        zonelist->_zonerefs[0].zone = NULL;
2839        zonelist->_zonerefs[0].zone_idx = 0;
2840    }
2841
2842    /* NUMA-aware ordering of nodes */
2843    local_node = pgdat->node_id;
2844    load = nr_online_nodes;
2845    prev_node = local_node;
2846    nodes_clear(used_mask);
2847
2848    memset(node_order, 0, sizeof(node_order));
2849    j = 0;
2850
2851    while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
2852        int distance = node_distance(local_node, node);
2853
2854        /*
2855         * If another node is sufficiently far away then it is better
2856         * to reclaim pages in a zone before going off node.
2857         */
2858        if (distance > RECLAIM_DISTANCE)
2859            zone_reclaim_mode = 1;
2860
2861        /*
2862         * We don't want to pressure a particular node.
2863         * So adding penalty to the first node in same
2864         * distance group to make it round-robin.
2865         */
2866        if (distance != node_distance(local_node, prev_node))
2867            node_load[node] = load;
2868
2869        prev_node = node;
2870        load--;
2871        if (order == ZONELIST_ORDER_NODE)
2872            build_zonelists_in_node_order(pgdat, node);
2873        else
2874            node_order[j++] = node; /* remember order */
2875    }
2876
2877    if (order == ZONELIST_ORDER_ZONE) {
2878        /* calculate node order -- i.e., DMA last! */
2879        build_zonelists_in_zone_order(pgdat, j);
2880    }
2881
2882    build_thisnode_zonelists(pgdat);
2883}
2884
2885/* Construct the zonelist performance cache - see further mmzone.h */
2886static void build_zonelist_cache(pg_data_t *pgdat)
2887{
2888    struct zonelist *zonelist;
2889    struct zonelist_cache *zlc;
2890    struct zoneref *z;
2891
2892    zonelist = &pgdat->node_zonelists[0];
2893    zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
2894    bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
2895    for (z = zonelist->_zonerefs; z->zone; z++)
2896        zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
2897}
2898
2899#ifdef CONFIG_HAVE_MEMORYLESS_NODES
2900/*
2901 * Return node id of node used for "local" allocations.
2902 * I.e., first node id of first zone in arg node's generic zonelist.
2903 * Used for initializing percpu 'numa_mem', which is used primarily
2904 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
2905 */
2906int local_memory_node(int node)
2907{
2908    struct zone *zone;
2909
2910    (void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
2911                   gfp_zone(GFP_KERNEL),
2912                   NULL,
2913                   &zone);
2914    return zone->node;
2915}
2916#endif
2917
2918#else /* CONFIG_NUMA */
2919
2920static void set_zonelist_order(void)
2921{
2922    current_zonelist_order = ZONELIST_ORDER_ZONE;
2923}
2924
2925static void build_zonelists(pg_data_t *pgdat)
2926{
2927    int node, local_node;
2928    enum zone_type j;
2929    struct zonelist *zonelist;
2930
2931    local_node = pgdat->node_id;
2932
2933    zonelist = &pgdat->node_zonelists[0];
2934    j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
2935
2936    /*
2937     * Now we build the zonelist so that it contains the zones
2938     * of all the other nodes.
2939     * We don't want to pressure a particular node, so when
2940     * building the zones for node N, we make sure that the
2941     * zones coming right after the local ones are those from
2942     * node N+1 (modulo N)
2943     */
2944    for (node = local_node + 1; node < MAX_NUMNODES; node++) {
2945        if (!node_online(node))
2946            continue;
2947        j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2948                            MAX_NR_ZONES - 1);
2949    }
2950    for (node = 0; node < local_node; node++) {
2951        if (!node_online(node))
2952            continue;
2953        j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2954                            MAX_NR_ZONES - 1);
2955    }
2956
2957    zonelist->_zonerefs[j].zone = NULL;
2958    zonelist->_zonerefs[j].zone_idx = 0;
2959}
2960
2961/* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
2962static void build_zonelist_cache(pg_data_t *pgdat)
2963{
2964    pgdat->node_zonelists[0].zlcache_ptr = NULL;
2965}
2966
2967#endif /* CONFIG_NUMA */
2968
2969/*
2970 * Boot pageset table. One per cpu which is going to be used for all
2971 * zones and all nodes. The parameters will be set in such a way
2972 * that an item put on a list will immediately be handed over to
2973 * the buddy list. This is safe since pageset manipulation is done
2974 * with interrupts disabled.
2975 *
2976 * The boot_pagesets must be kept even after bootup is complete for
2977 * unused processors and/or zones. They do play a role for bootstrapping
2978 * hotplugged processors.
2979 *
2980 * zoneinfo_show() and maybe other functions do
2981 * not check if the processor is online before following the pageset pointer.
2982 * Other parts of the kernel may not check if the zone is available.
2983 */
2984static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
2985static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
2986static void setup_zone_pageset(struct zone *zone);
2987
2988/*
2989 * Global mutex to protect against size modification of zonelists
2990 * as well as to serialize pageset setup for the new populated zone.
2991 */
2992DEFINE_MUTEX(zonelists_mutex);
2993
2994/* return values int ....just for stop_machine() */
2995static __init_refok int __build_all_zonelists(void *data)
2996{
2997    int nid;
2998    int cpu;
2999
3000#ifdef CONFIG_NUMA
3001    memset(node_load, 0, sizeof(node_load));
3002#endif
3003    for_each_online_node(nid) {
3004        pg_data_t *pgdat = NODE_DATA(nid);
3005
3006        build_zonelists(pgdat);
3007        build_zonelist_cache(pgdat);
3008    }
3009
3010#ifdef CONFIG_MEMORY_HOTPLUG
3011    /* Setup real pagesets for the new zone */
3012    if (data) {
3013        struct zone *zone = data;
3014        setup_zone_pageset(zone);
3015    }
3016#endif
3017
3018    /*
3019     * Initialize the boot_pagesets that are going to be used
3020     * for bootstrapping processors. The real pagesets for
3021     * each zone will be allocated later when the per cpu
3022     * allocator is available.
3023     *
3024     * boot_pagesets are used also for bootstrapping offline
3025     * cpus if the system is already booted because the pagesets
3026     * are needed to initialize allocators on a specific cpu too.
3027     * F.e. the percpu allocator needs the page allocator which
3028     * needs the percpu allocator in order to allocate its pagesets
3029     * (a chicken-egg dilemma).
3030     */
3031    for_each_possible_cpu(cpu) {
3032        setup_pageset(&per_cpu(boot_pageset, cpu), 0);
3033
3034#ifdef CONFIG_HAVE_MEMORYLESS_NODES
3035        /*
3036         * We now know the "local memory node" for each node--
3037         * i.e., the node of the first zone in the generic zonelist.
3038         * Set up numa_mem percpu variable for on-line cpus. During
3039         * boot, only the boot cpu should be on-line; we'll init the
3040         * secondary cpus' numa_mem as they come on-line. During
3041         * node/memory hotplug, we'll fixup all on-line cpus.
3042         */
3043        if (cpu_online(cpu))
3044            set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
3045#endif
3046    }
3047
3048    return 0;
3049}
3050
3051/*
3052 * Called with zonelists_mutex held always
3053 * unless system_state == SYSTEM_BOOTING.
3054 */
3055void build_all_zonelists(void *data)
3056{
3057    set_zonelist_order();
3058
3059    if (system_state == SYSTEM_BOOTING) {
3060        __build_all_zonelists(NULL);
3061        mminit_verify_zonelist();
3062        cpuset_init_current_mems_allowed();
3063    } else {
3064        /* we have to stop all cpus to guarantee there is no user
3065           of zonelist */
3066        stop_machine(__build_all_zonelists, data, NULL);
3067        /* cpuset refresh routine should be here */
3068    }
3069    vm_total_pages = nr_free_pagecache_pages();
3070    /*
3071     * Disable grouping by mobility if the number of pages in the
3072     * system is too low to allow the mechanism to work. It would be
3073     * more accurate, but expensive to check per-zone. This check is
3074     * made on memory-hotadd so a system can start with mobility
3075     * disabled and enable it later
3076     */
3077    if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
3078        page_group_by_mobility_disabled = 1;
3079    else
3080        page_group_by_mobility_disabled = 0;
3081
3082    printk("Built %i zonelists in %s order, mobility grouping %s. "
3083        "Total pages: %ld\n",
3084            nr_online_nodes,
3085            zonelist_order_name[current_zonelist_order],
3086            page_group_by_mobility_disabled ? "off" : "on",
3087            vm_total_pages);
3088#ifdef CONFIG_NUMA
3089    printk("Policy zone: %s\n", zone_names[policy_zone]);
3090#endif
3091}
3092
3093/*
3094 * Helper functions to size the waitqueue hash table.
3095 * Essentially these want to choose hash table sizes sufficiently
3096 * large so that collisions trying to wait on pages are rare.
3097 * But in fact, the number of active page waitqueues on typical
3098 * systems is ridiculously low, less than 200. So this is even
3099 * conservative, even though it seems large.
3100 *
3101 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
3102 * waitqueues, i.e. the size of the waitq table given the number of pages.
3103 */
3104#define PAGES_PER_WAITQUEUE 256
3105
3106#ifndef CONFIG_MEMORY_HOTPLUG
3107static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3108{
3109    unsigned long size = 1;
3110
3111    pages /= PAGES_PER_WAITQUEUE;
3112
3113    while (size < pages)
3114        size <<= 1;
3115
3116    /*
3117     * Once we have dozens or even hundreds of threads sleeping
3118     * on IO we've got bigger problems than wait queue collision.
3119     * Limit the size of the wait table to a reasonable size.
3120     */
3121    size = min(size, 4096UL);
3122
3123    return max(size, 4UL);
3124}
3125#else
3126/*
3127 * A zone's size might be changed by hot-add, so it is not possible to determine
3128 * a suitable size for its wait_table. So we use the maximum size now.
3129 *
3130 * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie:
3131 *
3132 * i386 (preemption config) : 4096 x 16 = 64Kbyte.
3133 * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
3134 * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte.
3135 *
3136 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
3137 * or more by the traditional way. (See above). It equals:
3138 *
3139 * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte.
3140 * ia64(16K page size) : = ( 8G + 4M)byte.
3141 * powerpc (64K page size) : = (32G +16M)byte.
3142 */
3143static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3144{
3145    return 4096UL;
3146}
3147#endif
3148
3149/*
3150 * This is an integer logarithm so that shifts can be used later
3151 * to extract the more random high bits from the multiplicative
3152 * hash function before the remainder is taken.
3153 */
3154static inline unsigned long wait_table_bits(unsigned long size)
3155{
3156    return ffz(~size);
3157}
3158
3159#define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
3160
3161/*
3162 * Mark a number of pageblocks as MIGRATE_RESERVE. The number
3163 * of blocks reserved is based on min_wmark_pages(zone). The memory within
3164 * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
3165 * higher will lead to a bigger reserve which will get freed as contiguous
3166 * blocks as reclaim kicks in
3167 */
3168static void setup_zone_migrate_reserve(struct zone *zone)
3169{
3170    unsigned long start_pfn, pfn, end_pfn;
3171    struct page *page;
3172    unsigned long block_migratetype;
3173    int reserve;
3174
3175    /* Get the start pfn, end pfn and the number of blocks to reserve */
3176    start_pfn = zone->zone_start_pfn;
3177    end_pfn = start_pfn + zone->spanned_pages;
3178    reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
3179                            pageblock_order;
3180
3181    /*
3182     * Reserve blocks are generally in place to help high-order atomic
3183     * allocations that are short-lived. A min_free_kbytes value that
3184     * would result in more than 2 reserve blocks for atomic allocations
3185     * is assumed to be in place to help anti-fragmentation for the
3186     * future allocation of hugepages at runtime.
3187     */
3188    reserve = min(2, reserve);
3189
3190    for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
3191        if (!pfn_valid(pfn))
3192            continue;
3193        page = pfn_to_page(pfn);
3194
3195        /* Watch out for overlapping nodes */
3196        if (page_to_nid(page) != zone_to_nid(zone))
3197            continue;
3198
3199        /* Blocks with reserved pages will never free, skip them. */
3200        if (PageReserved(page))
3201            continue;
3202
3203        block_migratetype = get_pageblock_migratetype(page);
3204
3205        /* If this block is reserved, account for it */
3206        if (reserve > 0 && block_migratetype == MIGRATE_RESERVE) {
3207            reserve--;
3208            continue;
3209        }
3210
3211        /* Suitable for reserving if this block is movable */
3212        if (reserve > 0 && block_migratetype == MIGRATE_MOVABLE) {
3213            set_pageblock_migratetype(page, MIGRATE_RESERVE);
3214            move_freepages_block(zone, page, MIGRATE_RESERVE);
3215            reserve--;
3216            continue;
3217        }
3218
3219        /*
3220         * If the reserve is met and this is a previous reserved block,
3221         * take it back
3222         */
3223        if (block_migratetype == MIGRATE_RESERVE) {
3224            set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3225            move_freepages_block(zone, page, MIGRATE_MOVABLE);
3226        }
3227    }
3228}
3229
3230/*
3231 * Initially all pages are reserved - free ones are freed
3232 * up by free_all_bootmem() once the early boot process is
3233 * done. Non-atomic initialization, single-pass.
3234 */
3235void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
3236        unsigned long start_pfn, enum memmap_context context)
3237{
3238    struct page *page;
3239    unsigned long end_pfn = start_pfn + size;
3240    unsigned long pfn;
3241    struct zone *z;
3242
3243    if (highest_memmap_pfn < end_pfn - 1)
3244        highest_memmap_pfn = end_pfn - 1;
3245
3246    z = &NODE_DATA(nid)->node_zones[zone];
3247    for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3248        /*
3249         * There can be holes in boot-time mem_map[]s
3250         * handed to this function. They do not
3251         * exist on hotplugged memory.
3252         */
3253        if (context == MEMMAP_EARLY) {
3254            if (!early_pfn_valid(pfn))
3255                continue;
3256            if (!early_pfn_in_nid(pfn, nid))
3257                continue;
3258        }
3259        page = pfn_to_page(pfn);
3260        set_page_links(page, zone, nid, pfn);
3261        mminit_verify_page_links(page, zone, nid, pfn);
3262        init_page_count(page);
3263        reset_page_mapcount(page);
3264        SetPageReserved(page);
3265        /*
3266         * Mark the block movable so that blocks are reserved for
3267         * movable at startup. This will force kernel allocations
3268         * to reserve their blocks rather than leaking throughout
3269         * the address space during boot when many long-lived
3270         * kernel allocations are made. Later some blocks near
3271         * the start are marked MIGRATE_RESERVE by
3272         * setup_zone_migrate_reserve()
3273         *
3274         * bitmap is created for zone's valid pfn range. but memmap
3275         * can be created for invalid pages (for alignment)
3276         * check here not to call set_pageblock_migratetype() against
3277         * pfn out of zone.
3278         */
3279        if ((z->zone_start_pfn <= pfn)
3280            && (pfn < z->zone_start_pfn + z->spanned_pages)
3281            && !(pfn & (pageblock_nr_pages - 1)))
3282            set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3283
3284        INIT_LIST_HEAD(&page->lru);
3285#ifdef WANT_PAGE_VIRTUAL
3286        /* The shift won't overflow because ZONE_NORMAL is below 4G. */
3287        if (!is_highmem_idx(zone))
3288            set_page_address(page, __va(pfn << PAGE_SHIFT));
3289#endif
3290    }
3291}
3292
3293static void __meminit zone_init_free_lists(struct zone *zone)
3294{
3295    int order, t;
3296    for_each_migratetype_order(order, t) {
3297        INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
3298        zone->free_area[order].nr_free = 0;
3299    }
3300}
3301
3302#ifndef __HAVE_ARCH_MEMMAP_INIT
3303#define memmap_init(size, nid, zone, start_pfn) \
3304    memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
3305#endif
3306
3307static int zone_batchsize(struct zone *zone)
3308{
3309#ifdef CONFIG_MMU
3310    int batch;
3311
3312    /*
3313     * The per-cpu-pages pools are set to around 1000th of the
3314     * size of the zone. But no more than 1/2 of a meg.
3315     *
3316     * OK, so we don't know how big the cache is. So guess.
3317     */
3318    batch = zone->present_pages / 1024;
3319    if (batch * PAGE_SIZE > 512 * 1024)
3320        batch = (512 * 1024) / PAGE_SIZE;
3321    batch /= 4; /* We effectively *= 4 below */
3322    if (batch < 1)
3323        batch = 1;
3324
3325    /*
3326     * Clamp the batch to a 2^n - 1 value. Having a power
3327     * of 2 value was found to be more likely to have
3328     * suboptimal cache aliasing properties in some cases.
3329     *
3330     * For example if 2 tasks are alternately allocating
3331     * batches of pages, one task can end up with a lot
3332     * of pages of one half of the possible page colors
3333     * and the other with pages of the other colors.
3334     */
3335    batch = rounddown_pow_of_two(batch + batch/2) - 1;
3336
3337    return batch;
3338
3339#else
3340    /* The deferral and batching of frees should be suppressed under NOMMU
3341     * conditions.
3342     *
3343     * The problem is that NOMMU needs to be able to allocate large chunks
3344     * of contiguous memory as there's no hardware page translation to
3345     * assemble apparent contiguous memory from discontiguous pages.
3346     *
3347     * Queueing large contiguous runs of pages for batching, however,
3348     * causes the pages to actually be freed in smaller chunks. As there
3349     * can be a significant delay between the individual batches being
3350     * recycled, this leads to the once large chunks of space being
3351     * fragmented and becoming unavailable for high-order allocations.
3352     */
3353    return 0;
3354#endif
3355}
3356
3357static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
3358{
3359    struct per_cpu_pages *pcp;
3360    int migratetype;
3361
3362    memset(p, 0, sizeof(*p));
3363
3364    pcp = &p->pcp;
3365    pcp->count = 0;
3366    pcp->high = 6 * batch;
3367    pcp->batch = max(1UL, 1 * batch);
3368    for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
3369        INIT_LIST_HEAD(&pcp->lists[migratetype]);
3370}
3371
3372/*
3373 * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
3374 * to the value high for the pageset p.
3375 */
3376
3377static void setup_pagelist_highmark(struct per_cpu_pageset *p,
3378                unsigned long high)
3379{
3380    struct per_cpu_pages *pcp;
3381
3382    pcp = &p->pcp;
3383    pcp->high = high;
3384    pcp->batch = max(1UL, high/4);
3385    if ((high/4) > (PAGE_SHIFT * 8))
3386        pcp->batch = PAGE_SHIFT * 8;
3387}
3388
3389static __meminit void setup_zone_pageset(struct zone *zone)
3390{
3391    int cpu;
3392
3393    zone->pageset = alloc_percpu(struct per_cpu_pageset);
3394
3395    for_each_possible_cpu(cpu) {
3396        struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
3397
3398        setup_pageset(pcp, zone_batchsize(zone));
3399
3400        if (percpu_pagelist_fraction)
3401            setup_pagelist_highmark(pcp,
3402                (zone->present_pages /
3403                    percpu_pagelist_fraction));
3404    }
3405}
3406
3407/*
3408 * Allocate per cpu pagesets and initialize them.
3409 * Before this call only boot pagesets were available.
3410 */
3411void __init setup_per_cpu_pageset(void)
3412{
3413    struct zone *zone;
3414
3415    for_each_populated_zone(zone)
3416        setup_zone_pageset(zone);
3417}
3418
3419static noinline __init_refok
3420int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
3421{
3422    int i;
3423    struct pglist_data *pgdat = zone->zone_pgdat;
3424    size_t alloc_size;
3425
3426    /*
3427     * The per-page waitqueue mechanism uses hashed waitqueues
3428     * per zone.
3429     */
3430    zone->wait_table_hash_nr_entries =
3431         wait_table_hash_nr_entries(zone_size_pages);
3432    zone->wait_table_bits =
3433        wait_table_bits(zone->wait_table_hash_nr_entries);
3434    alloc_size = zone->wait_table_hash_nr_entries
3435                    * sizeof(wait_queue_head_t);
3436
3437    if (!slab_is_available()) {
3438        zone->wait_table = (wait_queue_head_t *)
3439            alloc_bootmem_node(pgdat, alloc_size);
3440    } else {
3441        /*
3442         * This case means that a zone whose size was 0 gets new memory
3443         * via memory hot-add.
3444         * But it may be the case that a new node was hot-added. In
3445         * this case vmalloc() will not be able to use this new node's
3446         * memory - this wait_table must be initialized to use this new
3447         * node itself as well.
3448         * To use this new node's memory, further consideration will be
3449         * necessary.
3450         */
3451        zone->wait_table = vmalloc(alloc_size);
3452    }
3453    if (!zone->wait_table)
3454        return -ENOMEM;
3455
3456    for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
3457        init_waitqueue_head(zone->wait_table + i);
3458
3459    return 0;
3460}
3461
3462static int __zone_pcp_update(void *data)
3463{
3464    struct zone *zone = data;
3465    int cpu;
3466    unsigned long batch = zone_batchsize(zone), flags;
3467
3468    for_each_possible_cpu(cpu) {
3469        struct per_cpu_pageset *pset;
3470        struct per_cpu_pages *pcp;
3471
3472        pset = per_cpu_ptr(zone->pageset, cpu);
3473        pcp = &pset->pcp;
3474
3475        local_irq_save(flags);
3476        free_pcppages_bulk(zone, pcp->count, pcp);
3477        setup_pageset(pset, batch);
3478        local_irq_restore(flags);
3479    }
3480    return 0;
3481}
3482
3483void zone_pcp_update(struct zone *zone)
3484{
3485    stop_machine(__zone_pcp_update, zone, NULL);
3486}
3487
3488static __meminit void zone_pcp_init(struct zone *zone)
3489{
3490    /*
3491     * per cpu subsystem is not up at this point. The following code
3492     * relies on the ability of the linker to provide the
3493     * offset of a (static) per cpu variable into the per cpu area.
3494     */
3495    zone->pageset = &boot_pageset;
3496
3497    if (zone->present_pages)
3498        printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n",
3499            zone->name, zone->present_pages,
3500                     zone_batchsize(zone));
3501}
3502
3503__meminit int init_currently_empty_zone(struct zone *zone,
3504                    unsigned long zone_start_pfn,
3505                    unsigned long size,
3506                    enum memmap_context context)
3507{
3508    struct pglist_data *pgdat = zone->zone_pgdat;
3509    int ret;
3510    ret = zone_wait_table_init(zone, size);
3511    if (ret)
3512        return ret;
3513    pgdat->nr_zones = zone_idx(zone) + 1;
3514
3515    zone->zone_start_pfn = zone_start_pfn;
3516
3517    mminit_dprintk(MMINIT_TRACE, "memmap_init",
3518            "Initialising map node %d zone %lu pfns %lu -> %lu\n",
3519            pgdat->node_id,
3520            (unsigned long)zone_idx(zone),
3521            zone_start_pfn, (zone_start_pfn + size));
3522
3523    zone_init_free_lists(zone);
3524
3525    return 0;
3526}
3527
3528#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
3529/*
3530 * Basic iterator support. Return the first range of PFNs for a node
3531 * Note: nid == MAX_NUMNODES returns first region regardless of node
3532 */
3533static int __meminit first_active_region_index_in_nid(int nid)
3534{
3535    int i;
3536
3537    for (i = 0; i < nr_nodemap_entries; i++)
3538        if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
3539            return i;
3540
3541    return -1;
3542}
3543
3544/*
3545 * Basic iterator support. Return the next active range of PFNs for a node
3546 * Note: nid == MAX_NUMNODES returns next region regardless of node
3547 */
3548static int __meminit next_active_region_index_in_nid(int index, int nid)
3549{
3550    for (index = index + 1; index < nr_nodemap_entries; index++)
3551        if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
3552            return index;
3553
3554    return -1;
3555}
3556
3557#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
3558/*
3559 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
3560 * Architectures may implement their own version but if add_active_range()
3561 * was used and there are no special requirements, this is a convenient
3562 * alternative
3563 */
3564int __meminit __early_pfn_to_nid(unsigned long pfn)
3565{
3566    int i;
3567
3568    for (i = 0; i < nr_nodemap_entries; i++) {
3569        unsigned long start_pfn = early_node_map[i].start_pfn;
3570        unsigned long end_pfn = early_node_map[i].end_pfn;
3571
3572        if (start_pfn <= pfn && pfn < end_pfn)
3573            return early_node_map[i].nid;
3574    }
3575    /* This is a memory hole */
3576    return -1;
3577}
3578#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
3579
3580int __meminit early_pfn_to_nid(unsigned long pfn)
3581{
3582    int nid;
3583
3584    nid = __early_pfn_to_nid(pfn);
3585    if (nid >= 0)
3586        return nid;
3587    /* just returns 0 */
3588    return 0;
3589}
3590
3591#ifdef CONFIG_NODES_SPAN_OTHER_NODES
3592bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
3593{
3594    int nid;
3595
3596    nid = __early_pfn_to_nid(pfn);
3597    if (nid >= 0 && nid != node)
3598        return false;
3599    return true;
3600}
3601#endif
3602
3603/* Basic iterator support to walk early_node_map[] */
3604#define for_each_active_range_index_in_nid(i, nid) \
3605    for (i = first_active_region_index_in_nid(nid); i != -1; \
3606                i = next_active_region_index_in_nid(i, nid))
3607
3608/**
3609 * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
3610 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
3611 * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
3612 *
3613 * If an architecture guarantees that all ranges registered with
3614 * add_active_ranges() contain no holes and may be freed, this
3615 * this function may be used instead of calling free_bootmem() manually.
3616 */
3617void __init free_bootmem_with_active_regions(int nid,
3618                        unsigned long max_low_pfn)
3619{
3620    int i;
3621
3622    for_each_active_range_index_in_nid(i, nid) {
3623        unsigned long size_pages = 0;
3624        unsigned long end_pfn = early_node_map[i].end_pfn;
3625
3626        if (early_node_map[i].start_pfn >= max_low_pfn)
3627            continue;
3628
3629        if (end_pfn > max_low_pfn)
3630            end_pfn = max_low_pfn;
3631
3632        size_pages = end_pfn - early_node_map[i].start_pfn;
3633        free_bootmem_node(NODE_DATA(early_node_map[i].nid),
3634                PFN_PHYS(early_node_map[i].start_pfn),
3635                size_pages << PAGE_SHIFT);
3636    }
3637}
3638
3639int __init add_from_early_node_map(struct range *range, int az,
3640                   int nr_range, int nid)
3641{
3642    int i;
3643    u64 start, end;
3644
3645    /* need to go over early_node_map to find out good range for node */
3646    for_each_active_range_index_in_nid(i, nid) {
3647        start = early_node_map[i].start_pfn;
3648        end = early_node_map[i].end_pfn;
3649        nr_range = add_range(range, az, nr_range, start, end);
3650    }
3651    return nr_range;
3652}
3653
3654#ifdef CONFIG_NO_BOOTMEM
3655void * __init __alloc_memory_core_early(int nid, u64 size, u64 align,
3656                    u64 goal, u64 limit)
3657{
3658    int i;
3659    void *ptr;
3660
3661    if (limit > get_max_mapped())
3662        limit = get_max_mapped();
3663
3664    /* need to go over early_node_map to find out good range for node */
3665    for_each_active_range_index_in_nid(i, nid) {
3666        u64 addr;
3667        u64 ei_start, ei_last;
3668
3669        ei_last = early_node_map[i].end_pfn;
3670        ei_last <<= PAGE_SHIFT;
3671        ei_start = early_node_map[i].start_pfn;
3672        ei_start <<= PAGE_SHIFT;
3673        addr = find_early_area(ei_start, ei_last,
3674                     goal, limit, size, align);
3675
3676        if (addr == -1ULL)
3677            continue;
3678
3679#if 0
3680        printk(KERN_DEBUG "alloc (nid=%d %llx - %llx) (%llx - %llx) %llx %llx => %llx\n",
3681                nid,
3682                ei_start, ei_last, goal, limit, size,
3683                align, addr);
3684#endif
3685
3686        ptr = phys_to_virt(addr);
3687        memset(ptr, 0, size);
3688        reserve_early_without_check(addr, addr + size, "BOOTMEM");
3689        /*
3690         * The min_count is set to 0 so that bootmem allocated blocks
3691         * are never reported as leaks.
3692         */
3693        kmemleak_alloc(ptr, size, 0, 0);
3694        return ptr;
3695    }
3696
3697    return NULL;
3698}
3699#endif
3700
3701
3702void __init work_with_active_regions(int nid, work_fn_t work_fn, void *data)
3703{
3704    int i;
3705    int ret;
3706
3707    for_each_active_range_index_in_nid(i, nid) {
3708        ret = work_fn(early_node_map[i].start_pfn,
3709                  early_node_map[i].end_pfn, data);
3710        if (ret)
3711            break;
3712    }
3713}
3714/**
3715 * sparse_memory_present_with_active_regions - Call memory_present for each active range
3716 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
3717 *
3718 * If an architecture guarantees that all ranges registered with
3719 * add_active_ranges() contain no holes and may be freed, this
3720 * function may be used instead of calling memory_present() manually.
3721 */
3722void __init sparse_memory_present_with_active_regions(int nid)
3723{
3724    int i;
3725
3726    for_each_active_range_index_in_nid(i, nid)
3727        memory_present(early_node_map[i].nid,
3728                early_node_map[i].start_pfn,
3729                early_node_map[i].end_pfn);
3730}
3731
3732/**
3733 * get_pfn_range_for_nid - Return the start and end page frames for a node
3734 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
3735 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
3736 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
3737 *
3738 * It returns the start and end page frame of a node based on information
3739 * provided by an arch calling add_active_range(). If called for a node
3740 * with no available memory, a warning is printed and the start and end
3741 * PFNs will be 0.
3742 */
3743void __meminit get_pfn_range_for_nid(unsigned int nid,
3744            unsigned long *start_pfn, unsigned long *end_pfn)
3745{
3746    int i;
3747    *start_pfn = -1UL;
3748    *end_pfn = 0;
3749
3750    for_each_active_range_index_in_nid(i, nid) {
3751        *start_pfn = min(*start_pfn, early_node_map[i].start_pfn);
3752        *end_pfn = max(*end_pfn, early_node_map[i].end_pfn);
3753    }
3754
3755    if (*start_pfn == -1UL)
3756        *start_pfn = 0;
3757}
3758
3759/*
3760 * This finds a zone that can be used for ZONE_MOVABLE pages. The
3761 * assumption is made that zones within a node are ordered in monotonic
3762 * increasing memory addresses so that the "highest" populated zone is used
3763 */
3764static void __init find_usable_zone_for_movable(void)
3765{
3766    int zone_index;
3767    for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
3768        if (zone_index == ZONE_MOVABLE)
3769            continue;
3770
3771        if (arch_zone_highest_possible_pfn[zone_index] >
3772                arch_zone_lowest_possible_pfn[zone_index])
3773            break;
3774    }
3775
3776    VM_BUG_ON(zone_index == -1);
3777    movable_zone = zone_index;
3778}
3779
3780/*
3781 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
3782 * because it is sized independant of architecture. Unlike the other zones,
3783 * the starting point for ZONE_MOVABLE is not fixed. It may be different
3784 * in each node depending on the size of each node and how evenly kernelcore
3785 * is distributed. This helper function adjusts the zone ranges
3786 * provided by the architecture for a given node by using the end of the
3787 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
3788 * zones within a node are in order of monotonic increases memory addresses
3789 */
3790static void __meminit adjust_zone_range_for_zone_movable(int nid,
3791                    unsigned long zone_type,
3792                    unsigned long node_start_pfn,
3793                    unsigned long node_end_pfn,
3794                    unsigned long *zone_start_pfn,
3795                    unsigned long *zone_end_pfn)
3796{
3797    /* Only adjust if ZONE_MOVABLE is on this node */
3798    if (zone_movable_pfn[nid]) {
3799        /* Size ZONE_MOVABLE */
3800        if (zone_type == ZONE_MOVABLE) {
3801            *zone_start_pfn = zone_movable_pfn[nid];
3802            *zone_end_pfn = min(node_end_pfn,
3803                arch_zone_highest_possible_pfn[movable_zone]);
3804
3805        /* Adjust for ZONE_MOVABLE starting within this range */
3806        } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
3807                *zone_end_pfn > zone_movable_pfn[nid]) {
3808            *zone_end_pfn = zone_movable_pfn[nid];
3809
3810        /* Check if this whole range is within ZONE_MOVABLE */
3811        } else if (*zone_start_pfn >= zone_movable_pfn[nid])
3812            *zone_start_pfn = *zone_end_pfn;
3813    }
3814}
3815
3816/*
3817 * Return the number of pages a zone spans in a node, including holes
3818 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
3819 */
3820static unsigned long __meminit zone_spanned_pages_in_node(int nid,
3821                    unsigned long zone_type,
3822                    unsigned long *ignored)
3823{
3824    unsigned long node_start_pfn, node_end_pfn;
3825    unsigned long zone_start_pfn, zone_end_pfn;
3826
3827    /* Get the start and end of the node and zone */
3828    get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
3829    zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
3830    zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
3831    adjust_zone_range_for_zone_movable(nid, zone_type,
3832                node_start_pfn, node_end_pfn,
3833                &zone_start_pfn, &zone_end_pfn);
3834
3835    /* Check that this node has pages within the zone's required range */
3836    if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
3837        return 0;
3838
3839    /* Move the zone boundaries inside the node if necessary */
3840    zone_end_pfn = min(zone_end_pfn, node_end_pfn);
3841    zone_start_pfn = max(zone_start_pfn, node_start_pfn);
3842
3843    /* Return the spanned pages */
3844    return zone_end_pfn - zone_start_pfn;
3845}
3846
3847/*
3848 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
3849 * then all holes in the requested range will be accounted for.
3850 */
3851unsigned long __meminit __absent_pages_in_range(int nid,
3852                unsigned long range_start_pfn,
3853                unsigned long range_end_pfn)
3854{
3855    int i = 0;
3856    unsigned long prev_end_pfn = 0, hole_pages = 0;
3857    unsigned long start_pfn;
3858
3859    /* Find the end_pfn of the first active range of pfns in the node */
3860    i = first_active_region_index_in_nid(nid);
3861    if (i == -1)
3862        return 0;
3863
3864    prev_end_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
3865
3866    /* Account for ranges before physical memory on this node */
3867    if (early_node_map[i].start_pfn > range_start_pfn)
3868        hole_pages = prev_end_pfn - range_start_pfn;
3869
3870    /* Find all holes for the zone within the node */
3871    for (; i != -1; i = next_active_region_index_in_nid(i, nid)) {
3872
3873        /* No need to continue if prev_end_pfn is outside the zone */
3874        if (prev_end_pfn >= range_end_pfn)
3875            break;
3876
3877        /* Make sure the end of the zone is not within the hole */
3878        start_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
3879        prev_end_pfn = max(prev_end_pfn, range_start_pfn);
3880
3881        /* Update the hole size cound and move on */
3882        if (start_pfn > range_start_pfn) {
3883            BUG_ON(prev_end_pfn > start_pfn);
3884            hole_pages += start_pfn - prev_end_pfn;
3885        }
3886        prev_end_pfn = early_node_map[i].end_pfn;
3887    }
3888
3889    /* Account for ranges past physical memory on this node */
3890    if (range_end_pfn > prev_end_pfn)
3891        hole_pages += range_end_pfn -
3892                max(range_start_pfn, prev_end_pfn);
3893
3894    return hole_pages;
3895}
3896
3897/**
3898 * absent_pages_in_range - Return number of page frames in holes within a range
3899 * @start_pfn: The start PFN to start searching for holes
3900 * @end_pfn: The end PFN to stop searching for holes
3901 *
3902 * It returns the number of pages frames in memory holes within a range.
3903 */
3904unsigned long __init absent_pages_in_range(unsigned long start_pfn,
3905                            unsigned long end_pfn)
3906{
3907    return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
3908}
3909
3910/* Return the number of page frames in holes in a zone on a node */
3911static unsigned long __meminit zone_absent_pages_in_node(int nid,
3912                    unsigned long zone_type,
3913                    unsigned long *ignored)
3914{
3915    unsigned long node_start_pfn, node_end_pfn;
3916    unsigned long zone_start_pfn, zone_end_pfn;
3917
3918    get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
3919    zone_start_pfn = max(arch_zone_lowest_possible_pfn[zone_type],
3920                            node_start_pfn);
3921    zone_end_pfn = min(arch_zone_highest_possible_pfn[zone_type],
3922                            node_end_pfn);
3923
3924    adjust_zone_range_for_zone_movable(nid, zone_type,
3925            node_start_pfn, node_end_pfn,
3926            &zone_start_pfn, &zone_end_pfn);
3927    return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
3928}
3929
3930#else
3931static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
3932                    unsigned long zone_type,
3933                    unsigned long *zones_size)
3934{
3935    return zones_size[zone_type];
3936}
3937
3938static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
3939                        unsigned long zone_type,
3940                        unsigned long *zholes_size)
3941{
3942    if (!zholes_size)
3943        return 0;
3944
3945    return zholes_size[zone_type];
3946}
3947
3948#endif
3949
3950static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
3951        unsigned long *zones_size, unsigned long *zholes_size)
3952{
3953    unsigned long realtotalpages, totalpages = 0;
3954    enum zone_type i;
3955
3956    for (i = 0; i < MAX_NR_ZONES; i++)
3957        totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
3958                                zones_size);
3959    pgdat->node_spanned_pages = totalpages;
3960
3961    realtotalpages = totalpages;
3962    for (i = 0; i < MAX_NR_ZONES; i++)
3963        realtotalpages -=
3964            zone_absent_pages_in_node(pgdat->node_id, i,
3965                                zholes_size);
3966    pgdat->node_present_pages = realtotalpages;
3967    printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
3968                            realtotalpages);
3969}
3970
3971#ifndef CONFIG_SPARSEMEM
3972/*
3973 * Calculate the size of the zone->blockflags rounded to an unsigned long
3974 * Start by making sure zonesize is a multiple of pageblock_order by rounding
3975 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
3976 * round what is now in bits to nearest long in bits, then return it in
3977 * bytes.
3978 */
3979static unsigned long __init usemap_size(unsigned long zonesize)
3980{
3981    unsigned long usemapsize;
3982
3983    usemapsize = roundup(zonesize, pageblock_nr_pages);
3984    usemapsize = usemapsize >> pageblock_order;
3985    usemapsize *= NR_PAGEBLOCK_BITS;
3986    usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
3987
3988    return usemapsize / 8;
3989}
3990
3991static void __init setup_usemap(struct pglist_data *pgdat,
3992                struct zone *zone, unsigned long zonesize)
3993{
3994    unsigned long usemapsize = usemap_size(zonesize);
3995    zone->pageblock_flags = NULL;
3996    if (usemapsize)
3997        zone->pageblock_flags = alloc_bootmem_node(pgdat, usemapsize);
3998}
3999#else
4000static void inline setup_usemap(struct pglist_data *pgdat,
4001                struct zone *zone, unsigned long zonesize) {}
4002#endif /* CONFIG_SPARSEMEM */
4003
4004#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
4005
4006/* Return a sensible default order for the pageblock size. */
4007static inline int pageblock_default_order(void)
4008{
4009    if (HPAGE_SHIFT > PAGE_SHIFT)
4010        return HUGETLB_PAGE_ORDER;
4011
4012    return MAX_ORDER-1;
4013}
4014
4015/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
4016static inline void __init set_pageblock_order(unsigned int order)
4017{
4018    /* Check that pageblock_nr_pages has not already been setup */
4019    if (pageblock_order)
4020        return;
4021
4022    /*
4023     * Assume the largest contiguous order of interest is a huge page.
4024     * This value may be variable depending on boot parameters on IA64
4025     */
4026    pageblock_order = order;
4027}
4028#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4029
4030/*
4031 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
4032 * and pageblock_default_order() are unused as pageblock_order is set
4033 * at compile-time. See include/linux/pageblock-flags.h for the values of
4034 * pageblock_order based on the kernel config
4035 */
4036static inline int pageblock_default_order(unsigned int order)
4037{
4038    return MAX_ORDER-1;
4039}
4040#define set_pageblock_order(x) do {} while (0)
4041
4042#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4043
4044/*
4045 * Set up the zone data structures:
4046 * - mark all pages reserved
4047 * - mark all memory queues empty
4048 * - clear the memory bitmaps
4049 */
4050static void __paginginit free_area_init_core(struct pglist_data *pgdat,
4051        unsigned long *zones_size, unsigned long *zholes_size)
4052{
4053    enum zone_type j;
4054    int nid = pgdat->node_id;
4055    unsigned long zone_start_pfn = pgdat->node_start_pfn;
4056    int ret;
4057
4058    pgdat_resize_init(pgdat);
4059    pgdat->nr_zones = 0;
4060    init_waitqueue_head(&pgdat->kswapd_wait);
4061    pgdat->kswapd_max_order = 0;
4062    pgdat_page_cgroup_init(pgdat);
4063    
4064    for (j = 0; j < MAX_NR_ZONES; j++) {
4065        struct zone *zone = pgdat->node_zones + j;
4066        unsigned long size, realsize, memmap_pages;
4067        enum lru_list l;
4068
4069        size = zone_spanned_pages_in_node(nid, j, zones_size);
4070        realsize = size - zone_absent_pages_in_node(nid, j,
4071                                zholes_size);
4072
4073        /*
4074         * Adjust realsize so that it accounts for how much memory
4075         * is used by this zone for memmap. This affects the watermark
4076         * and per-cpu initialisations
4077         */
4078        memmap_pages =
4079            PAGE_ALIGN(size * sizeof(struct page)) >> PAGE_SHIFT;
4080        if (realsize >= memmap_pages) {
4081            realsize -= memmap_pages;
4082            if (memmap_pages)
4083                printk(KERN_DEBUG
4084                       " %s zone: %lu pages used for memmap\n",
4085                       zone_names[j], memmap_pages);
4086        } else
4087            printk(KERN_WARNING
4088                " %s zone: %lu pages exceeds realsize %lu\n",
4089                zone_names[j], memmap_pages, realsize);
4090
4091        /* Account for reserved pages */
4092        if (j == 0 && realsize > dma_reserve) {
4093            realsize -= dma_reserve;
4094            printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
4095                    zone_names[0], dma_reserve);
4096        }
4097
4098        if (!is_highmem_idx(j))
4099            nr_kernel_pages += realsize;
4100        nr_all_pages += realsize;
4101
4102        zone->spanned_pages = size;
4103        zone->present_pages = realsize;
4104#ifdef CONFIG_NUMA
4105        zone->node = nid;
4106        zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
4107                        / 100;
4108        zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
4109#endif
4110        zone->name = zone_names[j];
4111        spin_lock_init(&zone->lock);
4112        spin_lock_init(&zone->lru_lock);
4113        zone_seqlock_init(zone);
4114        zone->zone_pgdat = pgdat;
4115
4116        zone_pcp_init(zone);
4117        for_each_lru(l) {
4118            INIT_LIST_HEAD(&zone->lru[l].list);
4119            zone->reclaim_stat.nr_saved_scan[l] = 0;
4120        }
4121        zone->reclaim_stat.recent_rotated[0] = 0;
4122        zone->reclaim_stat.recent_rotated[1] = 0;
4123        zone->reclaim_stat.recent_scanned[0] = 0;
4124        zone->reclaim_stat.recent_scanned[1] = 0;
4125        zap_zone_vm_stats(zone);
4126        zone->flags = 0;
4127        if (!size)
4128            continue;
4129
4130        set_pageblock_order(pageblock_default_order());
4131        setup_usemap(pgdat, zone, size);
4132        ret = init_currently_empty_zone(zone, zone_start_pfn,
4133                        size, MEMMAP_EARLY);
4134        BUG_ON(ret);
4135        memmap_init(size, nid, j, zone_start_pfn);
4136        zone_start_pfn += size;
4137    }
4138}
4139
4140static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
4141{
4142    /* Skip empty nodes */
4143    if (!pgdat->node_spanned_pages)
4144        return;
4145
4146#ifdef CONFIG_FLAT_NODE_MEM_MAP
4147    /* ia64 gets its own node_mem_map, before this, without bootmem */
4148    if (!pgdat->node_mem_map) {
4149        unsigned long size, start, end;
4150        struct page *map;
4151
4152        /*
4153         * The zone's endpoints aren't required to be MAX_ORDER
4154         * aligned but the node_mem_map endpoints must be in order
4155         * for the buddy allocator to function correctly.
4156         */
4157        start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
4158        end = pgdat->node_start_pfn + pgdat->node_spanned_pages;
4159        end = ALIGN(end, MAX_ORDER_NR_PAGES);
4160        size = (end - start) * sizeof(struct page);
4161        map = alloc_remap(pgdat->node_id, size);
4162        if (!map)
4163            map = alloc_bootmem_node(pgdat, size);
4164        pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
4165    }
4166#ifndef CONFIG_NEED_MULTIPLE_NODES
4167    /*
4168     * With no DISCONTIG, the global mem_map is just set as node 0's
4169     */
4170    if (pgdat == NODE_DATA(0)) {
4171        mem_map = NODE_DATA(0)->node_mem_map;
4172#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
4173        if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
4174            mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
4175#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
4176    }
4177#endif
4178#endif /* CONFIG_FLAT_NODE_MEM_MAP */
4179}
4180
4181void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
4182        unsigned long node_start_pfn, unsigned long *zholes_size)
4183{
4184    pg_data_t *pgdat = NODE_DATA(nid);
4185
4186    pgdat->node_id = nid;
4187    pgdat->node_start_pfn = node_start_pfn;
4188    calculate_node_totalpages(pgdat, zones_size, zholes_size);
4189
4190    alloc_node_mem_map(pgdat);
4191#ifdef CONFIG_FLAT_NODE_MEM_MAP
4192    printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
4193        nid, (unsigned long)pgdat,
4194        (unsigned long)pgdat->node_mem_map);
4195#endif
4196
4197    free_area_init_core(pgdat, zones_size, zholes_size);
4198}
4199
4200#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
4201
4202#if MAX_NUMNODES > 1
4203/*
4204 * Figure out the number of possible node ids.
4205 */
4206static void __init setup_nr_node_ids(void)
4207{
4208    unsigned int node;
4209    unsigned int highest = 0;
4210
4211    for_each_node_mask(node, node_possible_map)
4212        highest = node;
4213    nr_node_ids = highest + 1;
4214}
4215#else
4216static inline void setup_nr_node_ids(void)
4217{
4218}
4219#endif
4220
4221/**
4222 * add_active_range - Register a range of PFNs backed by physical memory
4223 * @nid: The node ID the range resides on
4224 * @start_pfn: The start PFN of the available physical memory
4225 * @end_pfn: The end PFN of the available physical memory
4226 *
4227 * These ranges are stored in an early_node_map[] and later used by
4228 * free_area_init_nodes() to calculate zone sizes and holes. If the
4229 * range spans a memory hole, it is up to the architecture to ensure
4230 * the memory is not freed by the bootmem allocator. If possible
4231 * the range being registered will be merged with existing ranges.
4232 */
4233void __init add_active_range(unsigned int nid, unsigned long start_pfn,
4234                        unsigned long end_pfn)
4235{
4236    int i;
4237
4238    mminit_dprintk(MMINIT_TRACE, "memory_register",
4239            "Entering add_active_range(%d, %#lx, %#lx) "
4240            "%d entries of %d used\n",
4241            nid, start_pfn, end_pfn,
4242            nr_nodemap_entries, MAX_ACTIVE_REGIONS);
4243
4244    mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
4245
4246    /* Merge with existing active regions if possible */
4247    for (i = 0; i < nr_nodemap_entries; i++) {
4248        if (early_node_map[i].nid != nid)
4249            continue;
4250
4251        /* Skip if an existing region covers this new one */
4252        if (start_pfn >= early_node_map[i].start_pfn &&
4253                end_pfn <= early_node_map[i].end_pfn)
4254            return;
4255
4256        /* Merge forward if suitable */
4257        if (start_pfn <= early_node_map[i].end_pfn &&
4258                end_pfn > early_node_map[i].end_pfn) {
4259            early_node_map[i].end_pfn = end_pfn;
4260            return;
4261        }
4262
4263        /* Merge backward if suitable */
4264        if (start_pfn < early_node_map[i].start_pfn &&
4265                end_pfn >= early_node_map[i].start_pfn) {
4266            early_node_map[i].start_pfn = start_pfn;
4267            return;
4268        }
4269    }
4270
4271    /* Check that early_node_map is large enough */
4272    if (i >= MAX_ACTIVE_REGIONS) {
4273        printk(KERN_CRIT "More than %d memory regions, truncating\n",
4274                            MAX_ACTIVE_REGIONS);
4275        return;
4276    }
4277
4278    early_node_map[i].nid = nid;
4279    early_node_map[i].start_pfn = start_pfn;
4280    early_node_map[i].end_pfn = end_pfn;
4281    nr_nodemap_entries = i + 1;
4282}
4283
4284/**
4285 * remove_active_range - Shrink an existing registered range of PFNs
4286 * @nid: The node id the range is on that should be shrunk
4287 * @start_pfn: The new PFN of the range
4288 * @end_pfn: The new PFN of the range
4289 *
4290 * i386 with NUMA use alloc_remap() to store a node_mem_map on a local node.
4291 * The map is kept near the end physical page range that has already been
4292 * registered. This function allows an arch to shrink an existing registered
4293 * range.
4294 */
4295void __init remove_active_range(unsigned int nid, unsigned long start_pfn,
4296                unsigned long end_pfn)
4297{
4298    int i, j;
4299    int removed = 0;
4300
4301    printk(KERN_DEBUG "remove_active_range (%d, %lu, %lu)\n",
4302              nid, start_pfn, end_pfn);
4303
4304    /* Find the old active region end and shrink */
4305    for_each_active_range_index_in_nid(i, nid) {
4306        if (early_node_map[i].start_pfn >= start_pfn &&
4307            early_node_map[i].end_pfn <= end_pfn) {
4308            /* clear it */
4309            early_node_map[i].start_pfn = 0;
4310            early_node_map[i].end_pfn = 0;
4311            removed = 1;
4312            continue;
4313        }
4314        if (early_node_map[i].start_pfn < start_pfn &&
4315            early_node_map[i].end_pfn > start_pfn) {
4316            unsigned long temp_end_pfn = early_node_map[i].end_pfn;
4317            early_node_map[i].end_pfn = start_pfn;
4318            if (temp_end_pfn > end_pfn)
4319                add_active_range(nid, end_pfn, temp_end_pfn);
4320            continue;
4321        }
4322        if (early_node_map[i].start_pfn >= start_pfn &&
4323            early_node_map[i].end_pfn > end_pfn &&
4324            early_node_map[i].start_pfn < end_pfn) {
4325            early_node_map[i].start_pfn = end_pfn;
4326            continue;
4327        }
4328    }
4329
4330    if (!removed)
4331        return;
4332
4333    /* remove the blank ones */
4334    for (i = nr_nodemap_entries - 1; i > 0; i--) {
4335        if (early_node_map[i].nid != nid)
4336            continue;
4337        if (early_node_map[i].end_pfn)
4338            continue;
4339        /* we found it, get rid of it */
4340        for (j = i; j < nr_nodemap_entries - 1; j++)
4341            memcpy(&early_node_map[j], &early_node_map[j+1],
4342                sizeof(early_node_map[j]));
4343        j = nr_nodemap_entries - 1;
4344        memset(&early_node_map[j], 0, sizeof(early_node_map[j]));
4345        nr_nodemap_entries--;
4346    }
4347}
4348
4349/**
4350 * remove_all_active_ranges - Remove all currently registered regions
4351 *
4352 * During discovery, it may be found that a table like SRAT is invalid
4353 * and an alternative discovery method must be used. This function removes
4354 * all currently registered regions.
4355 */
4356void __init remove_all_active_ranges(void)
4357{
4358    memset(early_node_map, 0, sizeof(early_node_map));
4359    nr_nodemap_entries = 0;
4360}
4361
4362/* Compare two active node_active_regions */
4363static int __init cmp_node_active_region(const void *a, const void *b)
4364{
4365    struct node_active_region *arange = (struct node_active_region *)a;
4366    struct node_active_region *brange = (struct node_active_region *)b;
4367
4368    /* Done this way to avoid overflows */
4369    if (arange->start_pfn > brange->start_pfn)
4370        return 1;
4371    if (arange->start_pfn < brange->start_pfn)
4372        return -1;
4373
4374    return 0;
4375}
4376
4377/* sort the node_map by start_pfn */
4378void __init sort_node_map(void)
4379{
4380    sort(early_node_map, (size_t)nr_nodemap_entries,
4381            sizeof(struct node_active_region),
4382            cmp_node_active_region, NULL);
4383}
4384
4385/* Find the lowest pfn for a node */
4386static unsigned long __init find_min_pfn_for_node(int nid)
4387{
4388    int i;
4389    unsigned long min_pfn = ULONG_MAX;
4390
4391    /* Assuming a sorted map, the first range found has the starting pfn */
4392    for_each_active_range_index_in_nid(i, nid)
4393        min_pfn = min(min_pfn, early_node_map[i].start_pfn);
4394
4395    if (min_pfn == ULONG_MAX) {
4396        printk(KERN_WARNING
4397            "Could not find start_pfn for node %d\n", nid);
4398        return 0;
4399    }
4400
4401    return min_pfn;
4402}
4403
4404/**
4405 * find_min_pfn_with_active_regions - Find the minimum PFN registered
4406 *
4407 * It returns the minimum PFN based on information provided via
4408 * add_active_range().
4409 */
4410unsigned long __init find_min_pfn_with_active_regions(void)
4411{
4412    return find_min_pfn_for_node(MAX_NUMNODES);
4413}
4414
4415/*
4416 * early_calculate_totalpages()
4417 * Sum pages in active regions for movable zone.
4418 * Populate N_HIGH_MEMORY for calculating usable_nodes.
4419 */
4420static unsigned long __init early_calculate_totalpages(void)
4421{
4422    int i;
4423    unsigned long totalpages = 0;
4424
4425    for (i = 0; i < nr_nodemap_entries; i++) {
4426        unsigned long pages = early_node_map[i].end_pfn -
4427                        early_node_map[i].start_pfn;
4428        totalpages += pages;
4429        if (pages)
4430            node_set_state(early_node_map[i].nid, N_HIGH_MEMORY);
4431    }
4432      return totalpages;
4433}
4434
4435/*
4436 * Find the PFN the Movable zone begins in each node. Kernel memory
4437 * is spread evenly between nodes as long as the nodes have enough
4438 * memory. When they don't, some nodes will have more kernelcore than
4439 * others
4440 */
4441static void __init find_zone_movable_pfns_for_nodes(unsigned long *movable_pfn)
4442{
4443    int i, nid;
4444    unsigned long usable_startpfn;
4445    unsigned long kernelcore_node, kernelcore_remaining;
4446    /* save the state before borrow the nodemask */
4447    nodemask_t saved_node_state = node_states[N_HIGH_MEMORY];
4448    unsigned long totalpages = early_calculate_totalpages();
4449    int usable_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
4450
4451    /*
4452     * If movablecore was specified, calculate what size of
4453     * kernelcore that corresponds so that memory usable for
4454     * any allocation type is evenly spread. If both kernelcore
4455     * and movablecore are specified, then the value of kernelcore
4456     * will be used for required_kernelcore if it's greater than
4457     * what movablecore would have allowed.
4458     */
4459    if (required_movablecore) {
4460        unsigned long corepages;
4461
4462        /*
4463         * Round-up so that ZONE_MOVABLE is at least as large as what
4464         * was requested by the user
4465         */
4466        required_movablecore =
4467            roundup(required_movablecore, MAX_ORDER_NR_PAGES);
4468        corepages = totalpages - required_movablecore;
4469
4470        required_kernelcore = max(required_kernelcore, corepages);
4471    }
4472
4473    /* If kernelcore was not specified, there is no ZONE_MOVABLE */
4474    if (!required_kernelcore)
4475        goto out;
4476
4477    /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
4478    find_usable_zone_for_movable();
4479    usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
4480
4481restart:
4482    /* Spread kernelcore memory as evenly as possible throughout nodes */
4483    kernelcore_node = required_kernelcore / usable_nodes;
4484    for_each_node_state(nid, N_HIGH_MEMORY) {
4485        /*
4486         * Recalculate kernelcore_node if the division per node
4487         * now exceeds what is necessary to satisfy the requested
4488         * amount of memory for the kernel
4489         */
4490        if (required_kernelcore < kernelcore_node)
4491            kernelcore_node = required_kernelcore / usable_nodes;
4492
4493        /*
4494         * As the map is walked, we track how much memory is usable
4495         * by the kernel using kernelcore_remaining. When it is
4496         * 0, the rest of the node is usable by ZONE_MOVABLE
4497         */
4498        kernelcore_remaining = kernelcore_node;
4499
4500        /* Go through each range of PFNs within this node */
4501        for_each_active_range_index_in_nid(i, nid) {
4502            unsigned long start_pfn, end_pfn;
4503            unsigned long size_pages;
4504
4505            start_pfn = max(early_node_map[i].start_pfn,
4506                        zone_movable_pfn[nid]);
4507            end_pfn = early_node_map[i].end_pfn;
4508            if (start_pfn >= end_pfn)
4509                continue;
4510
4511            /* Account for what is only usable for kernelcore */
4512            if (start_pfn < usable_startpfn) {
4513                unsigned long kernel_pages;
4514                kernel_pages = min(end_pfn, usable_startpfn)
4515                                - start_pfn;
4516
4517                kernelcore_remaining -= min(kernel_pages,
4518                            kernelcore_remaining);
4519                required_kernelcore -= min(kernel_pages,
4520                            required_kernelcore);
4521
4522                /* Continue if range is now fully accounted */
4523                if (end_pfn <= usable_startpfn) {
4524
4525                    /*
4526                     * Push zone_movable_pfn to the end so
4527                     * that if we have to rebalance
4528                     * kernelcore across nodes, we will
4529                     * not double account here
4530                     */
4531                    zone_movable_pfn[nid] = end_pfn;
4532                    continue;
4533                }
4534                start_pfn = usable_startpfn;
4535            }
4536
4537            /*
4538             * The usable PFN range for ZONE_MOVABLE is from
4539             * start_pfn->end_pfn. Calculate size_pages as the
4540             * number of pages used as kernelcore
4541             */
4542            size_pages = end_pfn - start_pfn;
4543            if (size_pages > kernelcore_remaining)
4544                size_pages = kernelcore_remaining;
4545            zone_movable_pfn[nid] = start_pfn + size_pages;
4546
4547            /*
4548             * Some kernelcore has been met, update counts and
4549             * break if the kernelcore for this node has been
4550             * satisified
4551             */
4552            required_kernelcore -= min(required_kernelcore,
4553                                size_pages);
4554            kernelcore_remaining -= size_pages;
4555            if (!kernelcore_remaining)
4556                break;
4557        }
4558    }
4559
4560    /*
4561     * If there is still required_kernelcore, we do another pass with one
4562     * less node in the count. This will push zone_movable_pfn[nid] further
4563     * along on the nodes that still have memory until kernelcore is
4564     * satisified
4565     */
4566    usable_nodes--;
4567    if (usable_nodes && required_kernelcore > usable_nodes)
4568        goto restart;
4569
4570    /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
4571    for (nid = 0; nid < MAX_NUMNODES; nid++)
4572        zone_movable_pfn[nid] =
4573            roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
4574
4575out:
4576    /* restore the node_state */
4577    node_states[N_HIGH_MEMORY] = saved_node_state;
4578}
4579
4580/* Any regular memory on that node ? */
4581static void check_for_regular_memory(pg_data_t *pgdat)
4582{
4583#ifdef CONFIG_HIGHMEM
4584    enum zone_type zone_type;
4585
4586    for (zone_type = 0; zone_type <= ZONE_NORMAL; zone_type++) {
4587        struct zone *zone = &pgdat->node_zones[zone_type];
4588        if (zone->present_pages)
4589            node_set_state(zone_to_nid(zone), N_NORMAL_MEMORY);
4590    }
4591#endif
4592}
4593
4594/**
4595 * free_area_init_nodes - Initialise all pg_data_t and zone data
4596 * @max_zone_pfn: an array of max PFNs for each zone
4597 *
4598 * This will call free_area_init_node() for each active node in the system.
4599 * Using the page ranges provided by add_active_range(), the size of each
4600 * zone in each node and their holes is calculated. If the maximum PFN
4601 * between two adjacent zones match, it is assumed that the zone is empty.
4602 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
4603 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
4604 * starts where the previous one ended. For example, ZONE_DMA32 starts
4605 * at arch_max_dma_pfn.
4606 */
4607void __init free_area_init_nodes(unsigned long *max_zone_pfn)
4608{
4609    unsigned long nid;
4610    int i;
4611
4612    /* Sort early_node_map as initialisation assumes it is sorted */
4613    sort_node_map();
4614
4615    /* Record where the zone boundaries are */
4616    memset(arch_zone_lowest_possible_pfn, 0,
4617                sizeof(arch_zone_lowest_possible_pfn));
4618    memset(arch_zone_highest_possible_pfn, 0,
4619                sizeof(arch_zone_highest_possible_pfn));
4620    arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
4621    arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
4622    for (i = 1; i < MAX_NR_ZONES; i++) {
4623        if (i == ZONE_MOVABLE)
4624            continue;
4625        arch_zone_lowest_possible_pfn[i] =
4626            arch_zone_highest_possible_pfn[i-1];
4627        arch_zone_highest_possible_pfn[i] =
4628            max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
4629    }
4630    arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
4631    arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
4632
4633    /* Find the PFNs that ZONE_MOVABLE begins at in each node */
4634    memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
4635    find_zone_movable_pfns_for_nodes(zone_movable_pfn);
4636
4637    /* Print out the zone ranges */
4638    printk("Zone PFN ranges:\n");
4639    for (i = 0; i < MAX_NR_ZONES; i++) {
4640        if (i == ZONE_MOVABLE)
4641            continue;
4642        printk(" %-8s ", zone_names[i]);
4643        if (arch_zone_lowest_possible_pfn[i] ==
4644                arch_zone_highest_possible_pfn[i])
4645            printk("empty\n");
4646        else
4647            printk("%0#10lx -> %0#10lx\n",
4648                arch_zone_lowest_possible_pfn[i],
4649                arch_zone_highest_possible_pfn[i]);
4650    }
4651
4652    /* Print out the PFNs ZONE_MOVABLE begins at in each node */
4653    printk("Movable zone start PFN for each node\n");
4654    for (i = 0; i < MAX_NUMNODES; i++) {
4655        if (zone_movable_pfn[i])
4656            printk(" Node %d: %lu\n", i, zone_movable_pfn[i]);
4657    }
4658
4659    /* Print out the early_node_map[] */
4660    printk("early_node_map[%d] active PFN ranges\n", nr_nodemap_entries);
4661    for (i = 0; i < nr_nodemap_entries; i++)
4662        printk(" %3d: %0#10lx -> %0#10lx\n", early_node_map[i].nid,
4663                        early_node_map[i].start_pfn,
4664                        early_node_map[i].end_pfn);
4665
4666    /* Initialise every node */
4667    mminit_verify_pageflags_layout();
4668    setup_nr_node_ids();
4669    for_each_online_node(nid) {
4670        pg_data_t *pgdat = NODE_DATA(nid);
4671        free_area_init_node(nid, NULL,
4672                find_min_pfn_for_node(nid), NULL);
4673
4674        /* Any memory on that node */
4675        if (pgdat->node_present_pages)
4676            node_set_state(nid, N_HIGH_MEMORY);
4677        check_for_regular_memory(pgdat);
4678    }
4679}
4680
4681static int __init cmdline_parse_core(char *p, unsigned long *core)
4682{
4683    unsigned long long coremem;
4684    if (!p)
4685        return -EINVAL;
4686
4687    coremem = memparse(p, &p);
4688    *core = coremem >> PAGE_SHIFT;
4689
4690    /* Paranoid check that UL is enough for the coremem value */
4691    WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
4692
4693    return 0;
4694}
4695
4696/*
4697 * kernelcore=size sets the amount of memory for use for allocations that
4698 * cannot be reclaimed or migrated.
4699 */
4700static int __init cmdline_parse_kernelcore(char *p)
4701{
4702    return cmdline_parse_core(p, &required_kernelcore);
4703}
4704
4705/*
4706 * movablecore=size sets the amount of memory for use for allocations that
4707 * can be reclaimed or migrated.
4708 */
4709static int __init cmdline_parse_movablecore(char *p)
4710{
4711    return cmdline_parse_core(p, &required_movablecore);
4712}
4713
4714early_param("kernelcore", cmdline_parse_kernelcore);
4715early_param("movablecore", cmdline_parse_movablecore);
4716
4717#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
4718
4719/**
4720 * set_dma_reserve - set the specified number of pages reserved in the first zone
4721 * @new_dma_reserve: The number of pages to mark reserved
4722 *
4723 * The per-cpu batchsize and zone watermarks are determined by present_pages.
4724 * In the DMA zone, a significant percentage may be consumed by kernel image
4725 * and other unfreeable allocations which can skew the watermarks badly. This
4726 * function may optionally be used to account for unfreeable pages in the
4727 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
4728 * smaller per-cpu batchsize.
4729 */
4730void __init set_dma_reserve(unsigned long new_dma_reserve)
4731{
4732    dma_reserve = new_dma_reserve;
4733}
4734
4735#ifndef CONFIG_NEED_MULTIPLE_NODES
4736struct pglist_data __refdata contig_page_data = {
4737#ifndef CONFIG_NO_BOOTMEM
4738 .bdata = &bootmem_node_data[0]
4739#endif
4740 };
4741EXPORT_SYMBOL(contig_page_data);
4742#endif
4743
4744void __init free_area_init(unsigned long *zones_size)
4745{
4746    free_area_init_node(0, zones_size,
4747            __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
4748}
4749
4750static int page_alloc_cpu_notify(struct notifier_block *self,
4751                 unsigned long action, void *hcpu)
4752{
4753    int cpu = (unsigned long)hcpu;
4754
4755    if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
4756        drain_pages(cpu);
4757
4758        /*
4759         * Spill the event counters of the dead processor
4760         * into the current processors event counters.
4761         * This artificially elevates the count of the current
4762         * processor.
4763         */
4764        vm_events_fold_cpu(cpu);
4765
4766        /*
4767         * Zero the differential counters of the dead processor
4768         * so that the vm statistics are consistent.
4769         *
4770         * This is only okay since the processor is dead and cannot
4771         * race with what we are doing.
4772         */
4773        refresh_cpu_vm_stats(cpu);
4774    }
4775    return NOTIFY_OK;
4776}
4777
4778void __init page_alloc_init(void)
4779{
4780    hotcpu_notifier(page_alloc_cpu_notify, 0);
4781}
4782
4783/*
4784 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
4785 * or min_free_kbytes changes.
4786 */
4787static void calculate_totalreserve_pages(void)
4788{
4789    struct pglist_data *pgdat;
4790    unsigned long reserve_pages = 0;
4791    enum zone_type i, j;
4792
4793    for_each_online_pgdat(pgdat) {
4794        for (i = 0; i < MAX_NR_ZONES; i++) {
4795            struct zone *zone = pgdat->node_zones + i;
4796            unsigned long max = 0;
4797
4798            /* Find valid and maximum lowmem_reserve in the zone */
4799            for (j = i; j < MAX_NR_ZONES; j++) {
4800                if (zone->lowmem_reserve[j] > max)
4801                    max = zone->lowmem_reserve[j];
4802            }
4803
4804            /* we treat the high watermark as reserved pages. */
4805            max += high_wmark_pages(zone);
4806
4807            if (max > zone->present_pages)
4808                max = zone->present_pages;
4809            reserve_pages += max;
4810        }
4811    }
4812    totalreserve_pages = reserve_pages;
4813}
4814
4815/*
4816 * setup_per_zone_lowmem_reserve - called whenever
4817 * sysctl_lower_zone_reserve_ratio changes. Ensures that each zone
4818 * has a correct pages reserved value, so an adequate number of
4819 * pages are left in the zone after a successful __alloc_pages().
4820 */
4821static void setup_per_zone_lowmem_reserve(void)
4822{
4823    struct pglist_data *pgdat;
4824    enum zone_type j, idx;
4825
4826    for_each_online_pgdat(pgdat) {
4827        for (j = 0; j < MAX_NR_ZONES; j++) {
4828            struct zone *zone = pgdat->node_zones + j;
4829            unsigned long present_pages = zone->present_pages;
4830
4831            zone->lowmem_reserve[j] = 0;
4832
4833            idx = j;
4834            while (idx) {
4835                struct zone *lower_zone;
4836
4837                idx--;
4838
4839                if (sysctl_lowmem_reserve_ratio[idx] < 1)
4840                    sysctl_lowmem_reserve_ratio[idx] = 1;
4841
4842                lower_zone = pgdat->node_zones + idx;
4843                lower_zone->lowmem_reserve[j] = present_pages /
4844                    sysctl_lowmem_reserve_ratio[idx];
4845                present_pages += lower_zone->present_pages;
4846            }
4847        }
4848    }
4849
4850    /* update totalreserve_pages */
4851    calculate_totalreserve_pages();
4852}
4853
4854/**
4855 * setup_per_zone_wmarks - called when min_free_kbytes changes
4856 * or when memory is hot-{added|removed}
4857 *
4858 * Ensures that the watermark[min,low,high] values for each zone are set
4859 * correctly with respect to min_free_kbytes.
4860 */
4861void setup_per_zone_wmarks(void)
4862{
4863    unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
4864    unsigned long lowmem_pages = 0;
4865    struct zone *zone;
4866    unsigned long flags;
4867
4868    /* Calculate total number of !ZONE_HIGHMEM pages */
4869    for_each_zone(zone) {
4870        if (!is_highmem(zone))
4871            lowmem_pages += zone->present_pages;
4872    }
4873
4874    for_each_zone(zone) {
4875        u64 tmp;
4876
4877        spin_lock_irqsave(&zone->lock, flags);
4878        tmp = (u64)pages_min * zone->present_pages;
4879        do_div(tmp, lowmem_pages);
4880        if (is_highmem(zone)) {
4881            /*
4882             * __GFP_HIGH and PF_MEMALLOC allocations usually don't
4883             * need highmem pages, so cap pages_min to a small
4884             * value here.
4885             *
4886             * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
4887             * deltas controls asynch page reclaim, and so should
4888             * not be capped for highmem.
4889             */
4890            int min_pages;
4891
4892            min_pages = zone->present_pages / 1024;
4893            if (min_pages < SWAP_CLUSTER_MAX)
4894                min_pages = SWAP_CLUSTER_MAX;
4895            if (min_pages > 128)
4896                min_pages = 128;
4897            zone->watermark[WMARK_MIN] = min_pages;
4898        } else {
4899            /*
4900             * If it's a lowmem zone, reserve a number of pages
4901             * proportionate to the zone's size.
4902             */
4903            zone->watermark[WMARK_MIN] = tmp;
4904        }
4905
4906        zone->watermark[WMARK_LOW] = min_wmark_pages(zone) + (tmp >> 2);
4907        zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
4908        setup_zone_migrate_reserve(zone);
4909        spin_unlock_irqrestore(&zone->lock, flags);
4910    }
4911
4912    /* update totalreserve_pages */
4913    calculate_totalreserve_pages();
4914}
4915
4916/*
4917 * The inactive anon list should be small enough that the VM never has to
4918 * do too much work, but large enough that each inactive page has a chance
4919 * to be referenced again before it is swapped out.
4920 *
4921 * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
4922 * INACTIVE_ANON pages on this zone's LRU, maintained by the
4923 * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
4924 * the anonymous pages are kept on the inactive list.
4925 *
4926 * total target max
4927 * memory ratio inactive anon
4928 * -------------------------------------
4929 * 10MB 1 5MB
4930 * 100MB 1 50MB
4931 * 1GB 3 250MB
4932 * 10GB 10 0.9GB
4933 * 100GB 31 3GB
4934 * 1TB 101 10GB
4935 * 10TB 320 32GB
4936 */
4937void calculate_zone_inactive_ratio(struct zone *zone)
4938{
4939    unsigned int gb, ratio;
4940
4941    /* Zone size in gigabytes */
4942    gb = zone->present_pages >> (30 - PAGE_SHIFT);
4943    if (gb)
4944        ratio = int_sqrt(10 * gb);
4945    else
4946        ratio = 1;
4947
4948    zone->inactive_ratio = ratio;
4949}
4950
4951static void __init setup_per_zone_inactive_ratio(void)
4952{
4953    struct zone *zone;
4954
4955    for_each_zone(zone)
4956        calculate_zone_inactive_ratio(zone);
4957}
4958
4959/*
4960 * Initialise min_free_kbytes.
4961 *
4962 * For small machines we want it small (128k min). For large machines
4963 * we want it large (64MB max). But it is not linear, because network
4964 * bandwidth does not increase linearly with machine size. We use
4965 *
4966 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
4967 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
4968 *
4969 * which yields
4970 *
4971 * 16MB: 512k
4972 * 32MB: 724k
4973 * 64MB: 1024k
4974 * 128MB: 1448k
4975 * 256MB: 2048k
4976 * 512MB: 2896k
4977 * 1024MB: 4096k
4978 * 2048MB: 5792k
4979 * 4096MB: 8192k
4980 * 8192MB: 11584k
4981 * 16384MB: 16384k
4982 */
4983static int __init init_per_zone_wmark_min(void)
4984{
4985    unsigned long lowmem_kbytes;
4986
4987    lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
4988
4989    min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
4990    if (min_free_kbytes < 128)
4991        min_free_kbytes = 128;
4992    if (min_free_kbytes > 65536)
4993        min_free_kbytes = 65536;
4994    setup_per_zone_wmarks();
4995    setup_per_zone_lowmem_reserve();
4996    setup_per_zone_inactive_ratio();
4997    return 0;
4998}
4999module_init(init_per_zone_wmark_min)
5000
5001/*
5002 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
5003 * that we can call two helper functions whenever min_free_kbytes
5004 * changes.
5005 */
5006int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
5007    void __user *buffer, size_t *length, loff_t *ppos)
5008{
5009    proc_dointvec(table, write, buffer, length, ppos);
5010    if (write)
5011        setup_per_zone_wmarks();
5012    return 0;
5013}
5014
5015#ifdef CONFIG_NUMA
5016int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
5017    void __user *buffer, size_t *length, loff_t *ppos)
5018{
5019    struct zone *zone;
5020    int rc;
5021
5022    rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5023    if (rc)
5024        return rc;
5025
5026    for_each_zone(zone)
5027        zone->min_unmapped_pages = (zone->present_pages *
5028                sysctl_min_unmapped_ratio) / 100;
5029    return 0;
5030}
5031
5032int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
5033    void __user *buffer, size_t *length, loff_t *ppos)
5034{
5035    struct zone *zone;
5036    int rc;
5037
5038    rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5039    if (rc)
5040        return rc;
5041
5042    for_each_zone(zone)
5043        zone->min_slab_pages = (zone->present_pages *
5044                sysctl_min_slab_ratio) / 100;
5045    return 0;
5046}
5047#endif
5048
5049/*
5050 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
5051 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
5052 * whenever sysctl_lowmem_reserve_ratio changes.
5053 *
5054 * The reserve ratio obviously has absolutely no relation with the
5055 * minimum watermarks. The lowmem reserve ratio can only make sense
5056 * if in function of the boot time zone sizes.
5057 */
5058int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
5059    void __user *buffer, size_t *length, loff_t *ppos)
5060{
5061    proc_dointvec_minmax(table, write, buffer, length, ppos);
5062    setup_per_zone_lowmem_reserve();
5063    return 0;
5064}
5065
5066/*
5067 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
5068 * cpu. It is the fraction of total pages in each zone that a hot per cpu pagelist
5069 * can have before it gets flushed back to buddy allocator.
5070 */
5071
5072int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
5073    void __user *buffer, size_t *length, loff_t *ppos)
5074{
5075    struct zone *zone;
5076    unsigned int cpu;
5077    int ret;
5078
5079    ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
5080    if (!write || (ret == -EINVAL))
5081        return ret;
5082    for_each_populated_zone(zone) {
5083        for_each_possible_cpu(cpu) {
5084            unsigned long high;
5085            high = zone->present_pages / percpu_pagelist_fraction;
5086            setup_pagelist_highmark(
5087                per_cpu_ptr(zone->pageset, cpu), high);
5088        }
5089    }
5090    return 0;
5091}
5092
5093int hashdist = HASHDIST_DEFAULT;
5094
5095#ifdef CONFIG_NUMA
5096static int __init set_hashdist(char *str)
5097{
5098    if (!str)
5099        return 0;
5100    hashdist = simple_strtoul(str, &str, 0);
5101    return 1;
5102}
5103__setup("hashdist=", set_hashdist);
5104#endif
5105
5106/*
5107 * allocate a large system hash table from bootmem
5108 * - it is assumed that the hash table must contain an exact power-of-2
5109 * quantity of entries
5110 * - limit is the number of hash buckets, not the total allocation size
5111 */
5112void *__init alloc_large_system_hash(const char *tablename,
5113                     unsigned long bucketsize,
5114                     unsigned long numentries,
5115                     int scale,
5116                     int flags,
5117                     unsigned int *_hash_shift,
5118                     unsigned int *_hash_mask,
5119                     unsigned long limit)
5120{
5121    unsigned long long max = limit;
5122    unsigned long log2qty, size;
5123    void *table = NULL;
5124
5125    /* allow the kernel cmdline to have a say */
5126    if (!numentries) {
5127        /* round applicable memory size up to nearest megabyte */
5128        numentries = nr_kernel_pages;
5129        numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
5130        numentries >>= 20 - PAGE_SHIFT;
5131        numentries <<= 20 - PAGE_SHIFT;
5132
5133        /* limit to 1 bucket per 2^scale bytes of low memory */
5134        if (scale > PAGE_SHIFT)
5135            numentries >>= (scale - PAGE_SHIFT);
5136        else
5137            numentries <<= (PAGE_SHIFT - scale);
5138
5139        /* Make sure we've got at least a 0-order allocation.. */
5140        if (unlikely(flags & HASH_SMALL)) {
5141            /* Makes no sense without HASH_EARLY */
5142            WARN_ON(!(flags & HASH_EARLY));
5143            if (!(numentries >> *_hash_shift)) {
5144                numentries = 1UL << *_hash_shift;
5145                BUG_ON(!numentries);
5146            }
5147        } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
5148            numentries = PAGE_SIZE / bucketsize;
5149    }
5150    numentries = roundup_pow_of_two(numentries);
5151
5152    /* limit allocation size to 1/16 total memory by default */
5153    if (max == 0) {
5154        max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
5155        do_div(max, bucketsize);
5156    }
5157
5158    if (numentries > max)
5159        numentries = max;
5160
5161    log2qty = ilog2(numentries);
5162
5163    do {
5164        size = bucketsize << log2qty;
5165        if (flags & HASH_EARLY)
5166            table = alloc_bootmem_nopanic(size);
5167        else if (hashdist)
5168            table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
5169        else {
5170            /*
5171             * If bucketsize is not a power-of-two, we may free
5172             * some pages at the end of hash table which
5173             * alloc_pages_exact() automatically does
5174             */
5175            if (get_order(size) < MAX_ORDER) {
5176                table = alloc_pages_exact(size, GFP_ATOMIC);
5177                kmemleak_alloc(table, size, 1, GFP_ATOMIC);
5178            }
5179        }
5180    } while (!table && size > PAGE_SIZE && --log2qty);
5181
5182    if (!table)
5183        panic("Failed to allocate %s hash table\n", tablename);
5184
5185    printk(KERN_INFO "%s hash table entries: %ld (order: %d, %lu bytes)\n",
5186           tablename,
5187           (1UL << log2qty),
5188           ilog2(size) - PAGE_SHIFT,
5189           size);
5190
5191    if (_hash_shift)
5192        *_hash_shift = log2qty;
5193    if (_hash_mask)
5194        *_hash_mask = (1 << log2qty) - 1;
5195
5196    return table;
5197}
5198
5199/* Return a pointer to the bitmap storing bits affecting a block of pages */
5200static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
5201                            unsigned long pfn)
5202{
5203#ifdef CONFIG_SPARSEMEM
5204    return __pfn_to_section(pfn)->pageblock_flags;
5205#else
5206    return zone->pageblock_flags;
5207#endif /* CONFIG_SPARSEMEM */
5208}
5209
5210static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
5211{
5212#ifdef CONFIG_SPARSEMEM
5213    pfn &= (PAGES_PER_SECTION-1);
5214    return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5215#else
5216    pfn = pfn - zone->zone_start_pfn;
5217    return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5218#endif /* CONFIG_SPARSEMEM */
5219}
5220
5221/**
5222 * get_pageblock_flags_group - Return the requested group of flags for the pageblock_nr_pages block of pages
5223 * @page: The page within the block of interest
5224 * @start_bitidx: The first bit of interest to retrieve
5225 * @end_bitidx: The last bit of interest
5226 * returns pageblock_bits flags
5227 */
5228unsigned long get_pageblock_flags_group(struct page *page,
5229                    int start_bitidx, int end_bitidx)
5230{
5231    struct zone *zone;
5232    unsigned long *bitmap;
5233    unsigned long pfn, bitidx;
5234    unsigned long flags = 0;
5235    unsigned long value = 1;
5236
5237    zone = page_zone(page);
5238    pfn = page_to_pfn(page);
5239    bitmap = get_pageblock_bitmap(zone, pfn);
5240    bitidx = pfn_to_bitidx(zone, pfn);
5241
5242    for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5243        if (test_bit(bitidx + start_bitidx, bitmap))
5244            flags |= value;
5245
5246    return flags;
5247}
5248
5249/**
5250 * set_pageblock_flags_group - Set the requested group of flags for a pageblock_nr_pages block of pages
5251 * @page: The page within the block of interest
5252 * @start_bitidx: The first bit of interest
5253 * @end_bitidx: The last bit of interest
5254 * @flags: The flags to set
5255 */
5256void set_pageblock_flags_group(struct page *page, unsigned long flags,
5257                    int start_bitidx, int end_bitidx)
5258{
5259    struct zone *zone;
5260    unsigned long *bitmap;
5261    unsigned long pfn, bitidx;
5262    unsigned long value = 1;
5263
5264    zone = page_zone(page);
5265    pfn = page_to_pfn(page);
5266    bitmap = get_pageblock_bitmap(zone, pfn);
5267    bitidx = pfn_to_bitidx(zone, pfn);
5268    VM_BUG_ON(pfn < zone->zone_start_pfn);
5269    VM_BUG_ON(pfn >= zone->zone_start_pfn + zone->spanned_pages);
5270
5271    for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5272        if (flags & value)
5273            __set_bit(bitidx + start_bitidx, bitmap);
5274        else
5275            __clear_bit(bitidx + start_bitidx, bitmap);
5276}
5277
5278/*
5279 * This is designed as sub function...plz see page_isolation.c also.
5280 * set/clear page block's type to be ISOLATE.
5281 * page allocater never alloc memory from ISOLATE block.
5282 */
5283
5284int set_migratetype_isolate(struct page *page)
5285{
5286    struct zone *zone;
5287    struct page *curr_page;
5288    unsigned long flags, pfn, iter;
5289    unsigned long immobile = 0;
5290    struct memory_isolate_notify arg;
5291    int notifier_ret;
5292    int ret = -EBUSY;
5293    int zone_idx;
5294
5295    zone = page_zone(page);
5296    zone_idx = zone_idx(zone);
5297
5298    spin_lock_irqsave(&zone->lock, flags);
5299    if (get_pageblock_migratetype(page) == MIGRATE_MOVABLE ||
5300        zone_idx == ZONE_MOVABLE) {
5301        ret = 0;
5302        goto out;
5303    }
5304
5305    pfn = page_to_pfn(page);
5306    arg.start_pfn = pfn;
5307    arg.nr_pages = pageblock_nr_pages;
5308    arg.pages_found = 0;
5309
5310    /*
5311     * It may be possible to isolate a pageblock even if the
5312     * migratetype is not MIGRATE_MOVABLE. The memory isolation
5313     * notifier chain is used by balloon drivers to return the
5314     * number of pages in a range that are held by the balloon
5315     * driver to shrink memory. If all the pages are accounted for
5316     * by balloons, are free, or on the LRU, isolation can continue.
5317     * Later, for example, when memory hotplug notifier runs, these
5318     * pages reported as "can be isolated" should be isolated(freed)
5319     * by the balloon driver through the memory notifier chain.
5320     */
5321    notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
5322    notifier_ret = notifier_to_errno(notifier_ret);
5323    if (notifier_ret || !arg.pages_found)
5324        goto out;
5325
5326    for (iter = pfn; iter < (pfn + pageblock_nr_pages); iter++) {
5327        if (!pfn_valid_within(pfn))
5328            continue;
5329
5330        curr_page = pfn_to_page(iter);
5331        if (!page_count(curr_page) || PageLRU(curr_page))
5332            continue;
5333
5334        immobile++;
5335    }
5336
5337    if (arg.pages_found == immobile)
5338        ret = 0;
5339
5340out:
5341    if (!ret) {
5342        set_pageblock_migratetype(page, MIGRATE_ISOLATE);
5343        move_freepages_block(zone, page, MIGRATE_ISOLATE);
5344    }
5345
5346    spin_unlock_irqrestore(&zone->lock, flags);
5347    if (!ret)
5348        drain_all_pages();
5349    return ret;
5350}
5351
5352void unset_migratetype_isolate(struct page *page)
5353{
5354    struct zone *zone;
5355    unsigned long flags;
5356    zone = page_zone(page);
5357    spin_lock_irqsave(&zone->lock, flags);
5358    if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
5359        goto out;
5360    set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5361    move_freepages_block(zone, page, MIGRATE_MOVABLE);
5362out:
5363    spin_unlock_irqrestore(&zone->lock, flags);
5364}
5365
5366#ifdef CONFIG_MEMORY_HOTREMOVE
5367/*
5368 * All pages in the range must be isolated before calling this.
5369 */
5370void
5371__offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
5372{
5373    struct page *page;
5374    struct zone *zone;
5375    int order, i;
5376    unsigned long pfn;
5377    unsigned long flags;
5378    /* find the first valid pfn */
5379    for (pfn = start_pfn; pfn < end_pfn; pfn++)
5380        if (pfn_valid(pfn))
5381            break;
5382    if (pfn == end_pfn)
5383        return;
5384    zone = page_zone(pfn_to_page(pfn));
5385    spin_lock_irqsave(&zone->lock, flags);
5386    pfn = start_pfn;
5387    while (pfn < end_pfn) {
5388        if (!pfn_valid(pfn)) {
5389            pfn++;
5390            continue;
5391        }
5392        page = pfn_to_page(pfn);
5393        BUG_ON(page_count(page));
5394        BUG_ON(!PageBuddy(page));
5395        order = page_order(page);
5396#ifdef CONFIG_DEBUG_VM
5397        printk(KERN_INFO "remove from free list %lx %d %lx\n",
5398               pfn, 1 << order, end_pfn);
5399#endif
5400        list_del(&page->lru);
5401        rmv_page_order(page);
5402        zone->free_area[order].nr_free--;
5403        __mod_zone_page_state(zone, NR_FREE_PAGES,
5404                      - (1UL << order));
5405        for (i = 0; i < (1 << order); i++)
5406            SetPageReserved((page+i));
5407        pfn += (1 << order);
5408    }
5409    spin_unlock_irqrestore(&zone->lock, flags);
5410}
5411#endif
5412
5413#ifdef CONFIG_MEMORY_FAILURE
5414bool is_free_buddy_page(struct page *page)
5415{
5416    struct zone *zone = page_zone(page);
5417    unsigned long pfn = page_to_pfn(page);
5418    unsigned long flags;
5419    int order;
5420
5421    spin_lock_irqsave(&zone->lock, flags);
5422    for (order = 0; order < MAX_ORDER; order++) {
5423        struct page *page_head = page - (pfn & ((1 << order) - 1));
5424
5425        if (PageBuddy(page_head) && page_order(page_head) >= order)
5426            break;
5427    }
5428    spin_unlock_irqrestore(&zone->lock, flags);
5429
5430    return order < MAX_ORDER;
5431}
5432#endif
5433
5434static struct trace_print_flags pageflag_names[] = {
5435    {1UL << PG_locked, "locked" },
5436    {1UL << PG_error, "error" },
5437    {1UL << PG_referenced, "referenced" },
5438    {1UL << PG_uptodate, "uptodate" },
5439    {1UL << PG_dirty, "dirty" },
5440    {1UL << PG_lru, "lru" },
5441    {1UL << PG_active, "active" },
5442    {1UL << PG_slab, "slab" },
5443    {1UL << PG_owner_priv_1, "owner_priv_1" },
5444    {1UL << PG_arch_1, "arch_1" },
5445    {1UL << PG_reserved, "reserved" },
5446    {1UL << PG_private, "private" },
5447    {1UL << PG_private_2, "private_2" },
5448    {1UL << PG_writeback, "writeback" },
5449#ifdef CONFIG_PAGEFLAGS_EXTENDED
5450    {1UL << PG_head, "head" },
5451    {1UL << PG_tail, "tail" },
5452#else
5453    {1UL << PG_compound, "compound" },
5454#endif
5455    {1UL << PG_swapcache, "swapcache" },
5456    {1UL << PG_mappedtodisk, "mappedtodisk" },
5457    {1UL << PG_reclaim, "reclaim" },
5458    {1UL << PG_buddy, "buddy" },
5459    {1UL << PG_swapbacked, "swapbacked" },
5460    {1UL << PG_unevictable, "unevictable" },
5461#ifdef CONFIG_MMU
5462    {1UL << PG_mlocked, "mlocked" },
5463#endif
5464#ifdef CONFIG_ARCH_USES_PG_UNCACHED
5465    {1UL << PG_uncached, "uncached" },
5466#endif
5467#ifdef CONFIG_MEMORY_FAILURE
5468    {1UL << PG_hwpoison, "hwpoison" },
5469#endif
5470    {-1UL, NULL },
5471};
5472
5473static void dump_page_flags(unsigned long flags)
5474{
5475    const char *delim = "";
5476    unsigned long mask;
5477    int i;
5478
5479    printk(KERN_ALERT "page flags: %#lx(", flags);
5480
5481    /* remove zone id */
5482    flags &= (1UL << NR_PAGEFLAGS) - 1;
5483
5484    for (i = 0; pageflag_names[i].name && flags; i++) {
5485
5486        mask = pageflag_names[i].mask;
5487        if ((flags & mask) != mask)
5488            continue;
5489
5490        flags &= ~mask;
5491        printk("%s%s", delim, pageflag_names[i].name);
5492        delim = "|";
5493    }
5494
5495    /* check for left over flags */
5496    if (flags)
5497        printk("%s%#lx", delim, flags);
5498
5499    printk(")\n");
5500}
5501
5502void dump_page(struct page *page)
5503{
5504    printk(KERN_ALERT
5505           "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
5506        page, page_count(page), page_mapcount(page),
5507        page->mapping, page->index);
5508    dump_page_flags(page->flags);
5509}
5510

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