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/memblock.h>
25#include <linux/compiler.h>
26#include <linux/kernel.h>
27#include <linux/kmemcheck.h>
28#include <linux/module.h>
29#include <linux/suspend.h>
30#include <linux/pagevec.h>
31#include <linux/blkdev.h>
32#include <linux/slab.h>
33#include <linux/ratelimit.h>
34#include <linux/oom.h>
35#include <linux/notifier.h>
36#include <linux/topology.h>
37#include <linux/sysctl.h>
38#include <linux/cpu.h>
39#include <linux/cpuset.h>
40#include <linux/memory_hotplug.h>
41#include <linux/nodemask.h>
42#include <linux/vmalloc.h>
43#include <linux/vmstat.h>
44#include <linux/mempolicy.h>
45#include <linux/stop_machine.h>
46#include <linux/sort.h>
47#include <linux/pfn.h>
48#include <linux/backing-dev.h>
49#include <linux/fault-inject.h>
50#include <linux/page-isolation.h>
51#include <linux/page_cgroup.h>
52#include <linux/debugobjects.h>
53#include <linux/kmemleak.h>
54#include <linux/compaction.h>
55#include <trace/events/kmem.h>
56#include <linux/ftrace_event.h>
57#include <linux/memcontrol.h>
58#include <linux/prefetch.h>
59#include <linux/migrate.h>
60#include <linux/page-debug-flags.h>
61#include <linux/hugetlb.h>
62#include <linux/sched/rt.h>
63
64#include <asm/sections.h>
65#include <asm/tlbflush.h>
66#include <asm/div64.h>
67#include "internal.h"
68
69/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
70static DEFINE_MUTEX(pcp_batch_high_lock);
71
72#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
73DEFINE_PER_CPU(int, numa_node);
74EXPORT_PER_CPU_SYMBOL(numa_node);
75#endif
76
77#ifdef CONFIG_HAVE_MEMORYLESS_NODES
78/*
79 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
80 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
81 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
82 * defined in <linux/topology.h>.
83 */
84DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */
85EXPORT_PER_CPU_SYMBOL(_numa_mem_);
86#endif
87
88/*
89 * Array of node states.
90 */
91nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
92    [N_POSSIBLE] = NODE_MASK_ALL,
93    [N_ONLINE] = { { [0] = 1UL } },
94#ifndef CONFIG_NUMA
95    [N_NORMAL_MEMORY] = { { [0] = 1UL } },
96#ifdef CONFIG_HIGHMEM
97    [N_HIGH_MEMORY] = { { [0] = 1UL } },
98#endif
99#ifdef CONFIG_MOVABLE_NODE
100    [N_MEMORY] = { { [0] = 1UL } },
101#endif
102    [N_CPU] = { { [0] = 1UL } },
103#endif /* NUMA */
104};
105EXPORT_SYMBOL(node_states);
106
107/* Protect totalram_pages and zone->managed_pages */
108static DEFINE_SPINLOCK(managed_page_count_lock);
109
110unsigned long totalram_pages __read_mostly;
111unsigned long totalreserve_pages __read_mostly;
112/*
113 * When calculating the number of globally allowed dirty pages, there
114 * is a certain number of per-zone reserves that should not be
115 * considered dirtyable memory. This is the sum of those reserves
116 * over all existing zones that contribute dirtyable memory.
117 */
118unsigned long dirty_balance_reserve __read_mostly;
119
120int percpu_pagelist_fraction;
121gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
122
123#ifdef CONFIG_PM_SLEEP
124/*
125 * The following functions are used by the suspend/hibernate code to temporarily
126 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
127 * while devices are suspended. To avoid races with the suspend/hibernate code,
128 * they should always be called with pm_mutex held (gfp_allowed_mask also should
129 * only be modified with pm_mutex held, unless the suspend/hibernate code is
130 * guaranteed not to run in parallel with that modification).
131 */
132
133static gfp_t saved_gfp_mask;
134
135void pm_restore_gfp_mask(void)
136{
137    WARN_ON(!mutex_is_locked(&pm_mutex));
138    if (saved_gfp_mask) {
139        gfp_allowed_mask = saved_gfp_mask;
140        saved_gfp_mask = 0;
141    }
142}
143
144void pm_restrict_gfp_mask(void)
145{
146    WARN_ON(!mutex_is_locked(&pm_mutex));
147    WARN_ON(saved_gfp_mask);
148    saved_gfp_mask = gfp_allowed_mask;
149    gfp_allowed_mask &= ~GFP_IOFS;
150}
151
152bool pm_suspended_storage(void)
153{
154    if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS)
155        return false;
156    return true;
157}
158#endif /* CONFIG_PM_SLEEP */
159
160#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
161int pageblock_order __read_mostly;
162#endif
163
164static void __free_pages_ok(struct page *page, unsigned int order);
165
166/*
167 * results with 256, 32 in the lowmem_reserve sysctl:
168 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
169 * 1G machine -> (16M dma, 784M normal, 224M high)
170 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
171 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
172 * HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
173 *
174 * TBD: should special case ZONE_DMA32 machines here - in those we normally
175 * don't need any ZONE_NORMAL reservation
176 */
177int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
178#ifdef CONFIG_ZONE_DMA
179     256,
180#endif
181#ifdef CONFIG_ZONE_DMA32
182     256,
183#endif
184#ifdef CONFIG_HIGHMEM
185     32,
186#endif
187     32,
188};
189
190EXPORT_SYMBOL(totalram_pages);
191
192static char * const zone_names[MAX_NR_ZONES] = {
193#ifdef CONFIG_ZONE_DMA
194     "DMA",
195#endif
196#ifdef CONFIG_ZONE_DMA32
197     "DMA32",
198#endif
199     "Normal",
200#ifdef CONFIG_HIGHMEM
201     "HighMem",
202#endif
203     "Movable",
204};
205
206int min_free_kbytes = 1024;
207int user_min_free_kbytes;
208
209static unsigned long __meminitdata nr_kernel_pages;
210static unsigned long __meminitdata nr_all_pages;
211static unsigned long __meminitdata dma_reserve;
212
213#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
214static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
215static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
216static unsigned long __initdata required_kernelcore;
217static unsigned long __initdata required_movablecore;
218static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
219
220/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
221int movable_zone;
222EXPORT_SYMBOL(movable_zone);
223#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
224
225#if MAX_NUMNODES > 1
226int nr_node_ids __read_mostly = MAX_NUMNODES;
227int nr_online_nodes __read_mostly = 1;
228EXPORT_SYMBOL(nr_node_ids);
229EXPORT_SYMBOL(nr_online_nodes);
230#endif
231
232int page_group_by_mobility_disabled __read_mostly;
233
234void set_pageblock_migratetype(struct page *page, int migratetype)
235{
236
237    if (unlikely(page_group_by_mobility_disabled))
238        migratetype = MIGRATE_UNMOVABLE;
239
240    set_pageblock_flags_group(page, (unsigned long)migratetype,
241                    PB_migrate, PB_migrate_end);
242}
243
244bool oom_killer_disabled __read_mostly;
245
246#ifdef CONFIG_DEBUG_VM
247static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
248{
249    int ret = 0;
250    unsigned seq;
251    unsigned long pfn = page_to_pfn(page);
252    unsigned long sp, start_pfn;
253
254    do {
255        seq = zone_span_seqbegin(zone);
256        start_pfn = zone->zone_start_pfn;
257        sp = zone->spanned_pages;
258        if (!zone_spans_pfn(zone, pfn))
259            ret = 1;
260    } while (zone_span_seqretry(zone, seq));
261
262    if (ret)
263        pr_err("page %lu outside zone [ %lu - %lu ]\n",
264            pfn, start_pfn, start_pfn + sp);
265
266    return ret;
267}
268
269static int page_is_consistent(struct zone *zone, struct page *page)
270{
271    if (!pfn_valid_within(page_to_pfn(page)))
272        return 0;
273    if (zone != page_zone(page))
274        return 0;
275
276    return 1;
277}
278/*
279 * Temporary debugging check for pages not lying within a given zone.
280 */
281static int bad_range(struct zone *zone, struct page *page)
282{
283    if (page_outside_zone_boundaries(zone, page))
284        return 1;
285    if (!page_is_consistent(zone, page))
286        return 1;
287
288    return 0;
289}
290#else
291static inline int bad_range(struct zone *zone, struct page *page)
292{
293    return 0;
294}
295#endif
296
297static void bad_page(struct page *page)
298{
299    static unsigned long resume;
300    static unsigned long nr_shown;
301    static unsigned long nr_unshown;
302
303    /* Don't complain about poisoned pages */
304    if (PageHWPoison(page)) {
305        page_mapcount_reset(page); /* remove PageBuddy */
306        return;
307    }
308
309    /*
310     * Allow a burst of 60 reports, then keep quiet for that minute;
311     * or allow a steady drip of one report per second.
312     */
313    if (nr_shown == 60) {
314        if (time_before(jiffies, resume)) {
315            nr_unshown++;
316            goto out;
317        }
318        if (nr_unshown) {
319            printk(KERN_ALERT
320                  "BUG: Bad page state: %lu messages suppressed\n",
321                nr_unshown);
322            nr_unshown = 0;
323        }
324        nr_shown = 0;
325    }
326    if (nr_shown++ == 0)
327        resume = jiffies + 60 * HZ;
328
329    printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n",
330        current->comm, page_to_pfn(page));
331    dump_page(page);
332
333    print_modules();
334    dump_stack();
335out:
336    /* Leave bad fields for debug, except PageBuddy could make trouble */
337    page_mapcount_reset(page); /* remove PageBuddy */
338    add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
339}
340
341/*
342 * Higher-order pages are called "compound pages". They are structured thusly:
343 *
344 * The first PAGE_SIZE page is called the "head page".
345 *
346 * The remaining PAGE_SIZE pages are called "tail pages".
347 *
348 * All pages have PG_compound set. All tail pages have their ->first_page
349 * pointing at the head page.
350 *
351 * The first tail page's ->lru.next holds the address of the compound page's
352 * put_page() function. Its ->lru.prev holds the order of allocation.
353 * This usage means that zero-order pages may not be compound.
354 */
355
356static void free_compound_page(struct page *page)
357{
358    __free_pages_ok(page, compound_order(page));
359}
360
361void prep_compound_page(struct page *page, unsigned long order)
362{
363    int i;
364    int nr_pages = 1 << order;
365
366    set_compound_page_dtor(page, free_compound_page);
367    set_compound_order(page, order);
368    __SetPageHead(page);
369    for (i = 1; i < nr_pages; i++) {
370        struct page *p = page + i;
371        __SetPageTail(p);
372        set_page_count(p, 0);
373        p->first_page = page;
374    }
375}
376
377/* update __split_huge_page_refcount if you change this function */
378static int destroy_compound_page(struct page *page, unsigned long order)
379{
380    int i;
381    int nr_pages = 1 << order;
382    int bad = 0;
383
384    if (unlikely(compound_order(page) != order)) {
385        bad_page(page);
386        bad++;
387    }
388
389    __ClearPageHead(page);
390
391    for (i = 1; i < nr_pages; i++) {
392        struct page *p = page + i;
393
394        if (unlikely(!PageTail(p) || (p->first_page != page))) {
395            bad_page(page);
396            bad++;
397        }
398        __ClearPageTail(p);
399    }
400
401    return bad;
402}
403
404static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
405{
406    int i;
407
408    /*
409     * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
410     * and __GFP_HIGHMEM from hard or soft interrupt context.
411     */
412    VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
413    for (i = 0; i < (1 << order); i++)
414        clear_highpage(page + i);
415}
416
417#ifdef CONFIG_DEBUG_PAGEALLOC
418unsigned int _debug_guardpage_minorder;
419
420static int __init debug_guardpage_minorder_setup(char *buf)
421{
422    unsigned long res;
423
424    if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) {
425        printk(KERN_ERR "Bad debug_guardpage_minorder value\n");
426        return 0;
427    }
428    _debug_guardpage_minorder = res;
429    printk(KERN_INFO "Setting debug_guardpage_minorder to %lu\n", res);
430    return 0;
431}
432__setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup);
433
434static inline void set_page_guard_flag(struct page *page)
435{
436    __set_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
437}
438
439static inline void clear_page_guard_flag(struct page *page)
440{
441    __clear_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
442}
443#else
444static inline void set_page_guard_flag(struct page *page) { }
445static inline void clear_page_guard_flag(struct page *page) { }
446#endif
447
448static inline void set_page_order(struct page *page, int order)
449{
450    set_page_private(page, order);
451    __SetPageBuddy(page);
452}
453
454static inline void rmv_page_order(struct page *page)
455{
456    __ClearPageBuddy(page);
457    set_page_private(page, 0);
458}
459
460/*
461 * Locate the struct page for both the matching buddy in our
462 * pair (buddy1) and the combined O(n+1) page they form (page).
463 *
464 * 1) Any buddy B1 will have an order O twin B2 which satisfies
465 * the following equation:
466 * B2 = B1 ^ (1 << O)
467 * For example, if the starting buddy (buddy2) is #8 its order
468 * 1 buddy is #10:
469 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
470 *
471 * 2) Any buddy B will have an order O+1 parent P which
472 * satisfies the following equation:
473 * P = B & ~(1 << O)
474 *
475 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
476 */
477static inline unsigned long
478__find_buddy_index(unsigned long page_idx, unsigned int order)
479{
480    return page_idx ^ (1 << order);
481}
482
483/*
484 * This function checks whether a page is free && is the buddy
485 * we can do coalesce a page and its buddy if
486 * (a) the buddy is not in a hole &&
487 * (b) the buddy is in the buddy system &&
488 * (c) a page and its buddy have the same order &&
489 * (d) a page and its buddy are in the same zone.
490 *
491 * For recording whether a page is in the buddy system, we set ->_mapcount -2.
492 * Setting, clearing, and testing _mapcount -2 is serialized by zone->lock.
493 *
494 * For recording page's order, we use page_private(page).
495 */
496static inline int page_is_buddy(struct page *page, struct page *buddy,
497                                int order)
498{
499    if (!pfn_valid_within(page_to_pfn(buddy)))
500        return 0;
501
502    if (page_zone_id(page) != page_zone_id(buddy))
503        return 0;
504
505    if (page_is_guard(buddy) && page_order(buddy) == order) {
506        VM_BUG_ON(page_count(buddy) != 0);
507        return 1;
508    }
509
510    if (PageBuddy(buddy) && page_order(buddy) == order) {
511        VM_BUG_ON(page_count(buddy) != 0);
512        return 1;
513    }
514    return 0;
515}
516
517/*
518 * Freeing function for a buddy system allocator.
519 *
520 * The concept of a buddy system is to maintain direct-mapped table
521 * (containing bit values) for memory blocks of various "orders".
522 * The bottom level table contains the map for the smallest allocatable
523 * units of memory (here, pages), and each level above it describes
524 * pairs of units from the levels below, hence, "buddies".
525 * At a high level, all that happens here is marking the table entry
526 * at the bottom level available, and propagating the changes upward
527 * as necessary, plus some accounting needed to play nicely with other
528 * parts of the VM system.
529 * At each level, we keep a list of pages, which are heads of continuous
530 * free pages of length of (1 << order) and marked with _mapcount -2. Page's
531 * order is recorded in page_private(page) field.
532 * So when we are allocating or freeing one, we can derive the state of the
533 * other. That is, if we allocate a small block, and both were
534 * free, the remainder of the region must be split into blocks.
535 * If a block is freed, and its buddy is also free, then this
536 * triggers coalescing into a block of larger size.
537 *
538 * -- nyc
539 */
540
541static inline void __free_one_page(struct page *page,
542        struct zone *zone, unsigned int order,
543        int migratetype)
544{
545    unsigned long page_idx;
546    unsigned long combined_idx;
547    unsigned long uninitialized_var(buddy_idx);
548    struct page *buddy;
549
550    VM_BUG_ON(!zone_is_initialized(zone));
551
552    if (unlikely(PageCompound(page)))
553        if (unlikely(destroy_compound_page(page, order)))
554            return;
555
556    VM_BUG_ON(migratetype == -1);
557
558    page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
559
560    VM_BUG_ON(page_idx & ((1 << order) - 1));
561    VM_BUG_ON(bad_range(zone, page));
562
563    while (order < MAX_ORDER-1) {
564        buddy_idx = __find_buddy_index(page_idx, order);
565        buddy = page + (buddy_idx - page_idx);
566        if (!page_is_buddy(page, buddy, order))
567            break;
568        /*
569         * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
570         * merge with it and move up one order.
571         */
572        if (page_is_guard(buddy)) {
573            clear_page_guard_flag(buddy);
574            set_page_private(page, 0);
575            __mod_zone_freepage_state(zone, 1 << order,
576                          migratetype);
577        } else {
578            list_del(&buddy->lru);
579            zone->free_area[order].nr_free--;
580            rmv_page_order(buddy);
581        }
582        combined_idx = buddy_idx & page_idx;
583        page = page + (combined_idx - page_idx);
584        page_idx = combined_idx;
585        order++;
586    }
587    set_page_order(page, order);
588
589    /*
590     * If this is not the largest possible page, check if the buddy
591     * of the next-highest order is free. If it is, it's possible
592     * that pages are being freed that will coalesce soon. In case,
593     * that is happening, add the free page to the tail of the list
594     * so it's less likely to be used soon and more likely to be merged
595     * as a higher order page
596     */
597    if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
598        struct page *higher_page, *higher_buddy;
599        combined_idx = buddy_idx & page_idx;
600        higher_page = page + (combined_idx - page_idx);
601        buddy_idx = __find_buddy_index(combined_idx, order + 1);
602        higher_buddy = higher_page + (buddy_idx - combined_idx);
603        if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
604            list_add_tail(&page->lru,
605                &zone->free_area[order].free_list[migratetype]);
606            goto out;
607        }
608    }
609
610    list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
611out:
612    zone->free_area[order].nr_free++;
613}
614
615static inline int free_pages_check(struct page *page)
616{
617    if (unlikely(page_mapcount(page) |
618        (page->mapping != NULL) |
619        (atomic_read(&page->_count) != 0) |
620        (page->flags & PAGE_FLAGS_CHECK_AT_FREE) |
621        (mem_cgroup_bad_page_check(page)))) {
622        bad_page(page);
623        return 1;
624    }
625    page_nid_reset_last(page);
626    if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
627        page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
628    return 0;
629}
630
631/*
632 * Frees a number of pages from the PCP lists
633 * Assumes all pages on list are in same zone, and of same order.
634 * count is the number of pages to free.
635 *
636 * If the zone was previously in an "all pages pinned" state then look to
637 * see if this freeing clears that state.
638 *
639 * And clear the zone's pages_scanned counter, to hold off the "all pages are
640 * pinned" detection logic.
641 */
642static void free_pcppages_bulk(struct zone *zone, int count,
643                    struct per_cpu_pages *pcp)
644{
645    int migratetype = 0;
646    int batch_free = 0;
647    int to_free = count;
648
649    spin_lock(&zone->lock);
650    zone->all_unreclaimable = 0;
651    zone->pages_scanned = 0;
652
653    while (to_free) {
654        struct page *page;
655        struct list_head *list;
656
657        /*
658         * Remove pages from lists in a round-robin fashion. A
659         * batch_free count is maintained that is incremented when an
660         * empty list is encountered. This is so more pages are freed
661         * off fuller lists instead of spinning excessively around empty
662         * lists
663         */
664        do {
665            batch_free++;
666            if (++migratetype == MIGRATE_PCPTYPES)
667                migratetype = 0;
668            list = &pcp->lists[migratetype];
669        } while (list_empty(list));
670
671        /* This is the only non-empty list. Free them all. */
672        if (batch_free == MIGRATE_PCPTYPES)
673            batch_free = to_free;
674
675        do {
676            int mt; /* migratetype of the to-be-freed page */
677
678            page = list_entry(list->prev, struct page, lru);
679            /* must delete as __free_one_page list manipulates */
680            list_del(&page->lru);
681            mt = get_freepage_migratetype(page);
682            /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
683            __free_one_page(page, zone, 0, mt);
684            trace_mm_page_pcpu_drain(page, 0, mt);
685            if (likely(!is_migrate_isolate_page(page))) {
686                __mod_zone_page_state(zone, NR_FREE_PAGES, 1);
687                if (is_migrate_cma(mt))
688                    __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
689            }
690        } while (--to_free && --batch_free && !list_empty(list));
691    }
692    spin_unlock(&zone->lock);
693}
694
695static void free_one_page(struct zone *zone, struct page *page, int order,
696                int migratetype)
697{
698    spin_lock(&zone->lock);
699    zone->all_unreclaimable = 0;
700    zone->pages_scanned = 0;
701
702    __free_one_page(page, zone, order, migratetype);
703    if (unlikely(!is_migrate_isolate(migratetype)))
704        __mod_zone_freepage_state(zone, 1 << order, migratetype);
705    spin_unlock(&zone->lock);
706}
707
708static bool free_pages_prepare(struct page *page, unsigned int order)
709{
710    int i;
711    int bad = 0;
712
713    trace_mm_page_free(page, order);
714    kmemcheck_free_shadow(page, order);
715
716    if (PageAnon(page))
717        page->mapping = NULL;
718    for (i = 0; i < (1 << order); i++)
719        bad += free_pages_check(page + i);
720    if (bad)
721        return false;
722
723    if (!PageHighMem(page)) {
724        debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
725        debug_check_no_obj_freed(page_address(page),
726                       PAGE_SIZE << order);
727    }
728    arch_free_page(page, order);
729    kernel_map_pages(page, 1 << order, 0);
730
731    return true;
732}
733
734static void __free_pages_ok(struct page *page, unsigned int order)
735{
736    unsigned long flags;
737    int migratetype;
738
739    if (!free_pages_prepare(page, order))
740        return;
741
742    local_irq_save(flags);
743    __count_vm_events(PGFREE, 1 << order);
744    migratetype = get_pageblock_migratetype(page);
745    set_freepage_migratetype(page, migratetype);
746    free_one_page(page_zone(page), page, order, migratetype);
747    local_irq_restore(flags);
748}
749
750void __init __free_pages_bootmem(struct page *page, unsigned int order)
751{
752    unsigned int nr_pages = 1 << order;
753    unsigned int loop;
754
755    prefetchw(page);
756    for (loop = 0; loop < nr_pages; loop++) {
757        struct page *p = &page[loop];
758
759        if (loop + 1 < nr_pages)
760            prefetchw(p + 1);
761        __ClearPageReserved(p);
762        set_page_count(p, 0);
763    }
764
765    page_zone(page)->managed_pages += 1 << order;
766    set_page_refcounted(page);
767    __free_pages(page, order);
768}
769
770#ifdef CONFIG_CMA
771/* Free whole pageblock and set it's migration type to MIGRATE_CMA. */
772void __init init_cma_reserved_pageblock(struct page *page)
773{
774    unsigned i = pageblock_nr_pages;
775    struct page *p = page;
776
777    do {
778        __ClearPageReserved(p);
779        set_page_count(p, 0);
780    } while (++p, --i);
781
782    set_page_refcounted(page);
783    set_pageblock_migratetype(page, MIGRATE_CMA);
784    __free_pages(page, pageblock_order);
785    adjust_managed_page_count(page, pageblock_nr_pages);
786}
787#endif
788
789/*
790 * The order of subdivision here is critical for the IO subsystem.
791 * Please do not alter this order without good reasons and regression
792 * testing. Specifically, as large blocks of memory are subdivided,
793 * the order in which smaller blocks are delivered depends on the order
794 * they're subdivided in this function. This is the primary factor
795 * influencing the order in which pages are delivered to the IO
796 * subsystem according to empirical testing, and this is also justified
797 * by considering the behavior of a buddy system containing a single
798 * large block of memory acted on by a series of small allocations.
799 * This behavior is a critical factor in sglist merging's success.
800 *
801 * -- nyc
802 */
803static inline void expand(struct zone *zone, struct page *page,
804    int low, int high, struct free_area *area,
805    int migratetype)
806{
807    unsigned long size = 1 << high;
808
809    while (high > low) {
810        area--;
811        high--;
812        size >>= 1;
813        VM_BUG_ON(bad_range(zone, &page[size]));
814
815#ifdef CONFIG_DEBUG_PAGEALLOC
816        if (high < debug_guardpage_minorder()) {
817            /*
818             * Mark as guard pages (or page), that will allow to
819             * merge back to allocator when buddy will be freed.
820             * Corresponding page table entries will not be touched,
821             * pages will stay not present in virtual address space
822             */
823            INIT_LIST_HEAD(&page[size].lru);
824            set_page_guard_flag(&page[size]);
825            set_page_private(&page[size], high);
826            /* Guard pages are not available for any usage */
827            __mod_zone_freepage_state(zone, -(1 << high),
828                          migratetype);
829            continue;
830        }
831#endif
832        list_add(&page[size].lru, &area->free_list[migratetype]);
833        area->nr_free++;
834        set_page_order(&page[size], high);
835    }
836}
837
838/*
839 * This page is about to be returned from the page allocator
840 */
841static inline int check_new_page(struct page *page)
842{
843    if (unlikely(page_mapcount(page) |
844        (page->mapping != NULL) |
845        (atomic_read(&page->_count) != 0) |
846        (page->flags & PAGE_FLAGS_CHECK_AT_PREP) |
847        (mem_cgroup_bad_page_check(page)))) {
848        bad_page(page);
849        return 1;
850    }
851    return 0;
852}
853
854static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
855{
856    int i;
857
858    for (i = 0; i < (1 << order); i++) {
859        struct page *p = page + i;
860        if (unlikely(check_new_page(p)))
861            return 1;
862    }
863
864    set_page_private(page, 0);
865    set_page_refcounted(page);
866
867    arch_alloc_page(page, order);
868    kernel_map_pages(page, 1 << order, 1);
869
870    if (gfp_flags & __GFP_ZERO)
871        prep_zero_page(page, order, gfp_flags);
872
873    if (order && (gfp_flags & __GFP_COMP))
874        prep_compound_page(page, order);
875
876    return 0;
877}
878
879/*
880 * Go through the free lists for the given migratetype and remove
881 * the smallest available page from the freelists
882 */
883static inline
884struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
885                        int migratetype)
886{
887    unsigned int current_order;
888    struct free_area * area;
889    struct page *page;
890
891    /* Find a page of the appropriate size in the preferred list */
892    for (current_order = order; current_order < MAX_ORDER; ++current_order) {
893        area = &(zone->free_area[current_order]);
894        if (list_empty(&area->free_list[migratetype]))
895            continue;
896
897        page = list_entry(area->free_list[migratetype].next,
898                            struct page, lru);
899        list_del(&page->lru);
900        rmv_page_order(page);
901        area->nr_free--;
902        expand(zone, page, order, current_order, area, migratetype);
903        return page;
904    }
905
906    return NULL;
907}
908
909
910/*
911 * This array describes the order lists are fallen back to when
912 * the free lists for the desirable migrate type are depleted
913 */
914static int fallbacks[MIGRATE_TYPES][4] = {
915    [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
916    [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
917#ifdef CONFIG_CMA
918    [MIGRATE_MOVABLE] = { MIGRATE_CMA, MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
919    [MIGRATE_CMA] = { MIGRATE_RESERVE }, /* Never used */
920#else
921    [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
922#endif
923    [MIGRATE_RESERVE] = { MIGRATE_RESERVE }, /* Never used */
924#ifdef CONFIG_MEMORY_ISOLATION
925    [MIGRATE_ISOLATE] = { MIGRATE_RESERVE }, /* Never used */
926#endif
927};
928
929/*
930 * Move the free pages in a range to the free lists of the requested type.
931 * Note that start_page and end_pages are not aligned on a pageblock
932 * boundary. If alignment is required, use move_freepages_block()
933 */
934int move_freepages(struct zone *zone,
935              struct page *start_page, struct page *end_page,
936              int migratetype)
937{
938    struct page *page;
939    unsigned long order;
940    int pages_moved = 0;
941
942#ifndef CONFIG_HOLES_IN_ZONE
943    /*
944     * page_zone is not safe to call in this context when
945     * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
946     * anyway as we check zone boundaries in move_freepages_block().
947     * Remove at a later date when no bug reports exist related to
948     * grouping pages by mobility
949     */
950    BUG_ON(page_zone(start_page) != page_zone(end_page));
951#endif
952
953    for (page = start_page; page <= end_page;) {
954        /* Make sure we are not inadvertently changing nodes */
955        VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
956
957        if (!pfn_valid_within(page_to_pfn(page))) {
958            page++;
959            continue;
960        }
961
962        if (!PageBuddy(page)) {
963            page++;
964            continue;
965        }
966
967        order = page_order(page);
968        list_move(&page->lru,
969              &zone->free_area[order].free_list[migratetype]);
970        set_freepage_migratetype(page, migratetype);
971        page += 1 << order;
972        pages_moved += 1 << order;
973    }
974
975    return pages_moved;
976}
977
978int move_freepages_block(struct zone *zone, struct page *page,
979                int migratetype)
980{
981    unsigned long start_pfn, end_pfn;
982    struct page *start_page, *end_page;
983
984    start_pfn = page_to_pfn(page);
985    start_pfn = start_pfn & ~(pageblock_nr_pages-1);
986    start_page = pfn_to_page(start_pfn);
987    end_page = start_page + pageblock_nr_pages - 1;
988    end_pfn = start_pfn + pageblock_nr_pages - 1;
989
990    /* Do not cross zone boundaries */
991    if (!zone_spans_pfn(zone, start_pfn))
992        start_page = page;
993    if (!zone_spans_pfn(zone, end_pfn))
994        return 0;
995
996    return move_freepages(zone, start_page, end_page, migratetype);
997}
998
999static void change_pageblock_range(struct page *pageblock_page,
1000                    int start_order, int migratetype)
1001{
1002    int nr_pageblocks = 1 << (start_order - pageblock_order);
1003
1004    while (nr_pageblocks--) {
1005        set_pageblock_migratetype(pageblock_page, migratetype);
1006        pageblock_page += pageblock_nr_pages;
1007    }
1008}
1009
1010/* Remove an element from the buddy allocator from the fallback list */
1011static inline struct page *
1012__rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
1013{
1014    struct free_area * area;
1015    int current_order;
1016    struct page *page;
1017    int migratetype, i;
1018
1019    /* Find the largest possible block of pages in the other list */
1020    for (current_order = MAX_ORDER-1; current_order >= order;
1021                        --current_order) {
1022        for (i = 0;; i++) {
1023            migratetype = fallbacks[start_migratetype][i];
1024
1025            /* MIGRATE_RESERVE handled later if necessary */
1026            if (migratetype == MIGRATE_RESERVE)
1027                break;
1028
1029            area = &(zone->free_area[current_order]);
1030            if (list_empty(&area->free_list[migratetype]))
1031                continue;
1032
1033            page = list_entry(area->free_list[migratetype].next,
1034                    struct page, lru);
1035            area->nr_free--;
1036
1037            /*
1038             * If breaking a large block of pages, move all free
1039             * pages to the preferred allocation list. If falling
1040             * back for a reclaimable kernel allocation, be more
1041             * aggressive about taking ownership of free pages
1042             *
1043             * On the other hand, never change migration
1044             * type of MIGRATE_CMA pageblocks nor move CMA
1045             * pages on different free lists. We don't
1046             * want unmovable pages to be allocated from
1047             * MIGRATE_CMA areas.
1048             */
1049            if (!is_migrate_cma(migratetype) &&
1050                (current_order >= pageblock_order / 2 ||
1051                 start_migratetype == MIGRATE_RECLAIMABLE ||
1052                 page_group_by_mobility_disabled)) {
1053                int pages;
1054                pages = move_freepages_block(zone, page,
1055                                start_migratetype);
1056
1057                /* Claim the whole block if over half of it is free */
1058                if (pages >= (1 << (pageblock_order-1)) ||
1059                        page_group_by_mobility_disabled)
1060                    set_pageblock_migratetype(page,
1061                                start_migratetype);
1062
1063                migratetype = start_migratetype;
1064            }
1065
1066            /* Remove the page from the freelists */
1067            list_del(&page->lru);
1068            rmv_page_order(page);
1069
1070            /* Take ownership for orders >= pageblock_order */
1071            if (current_order >= pageblock_order &&
1072                !is_migrate_cma(migratetype))
1073                change_pageblock_range(page, current_order,
1074                            start_migratetype);
1075
1076            expand(zone, page, order, current_order, area,
1077                   is_migrate_cma(migratetype)
1078                 ? migratetype : start_migratetype);
1079
1080            trace_mm_page_alloc_extfrag(page, order, current_order,
1081                start_migratetype, migratetype);
1082
1083            return page;
1084        }
1085    }
1086
1087    return NULL;
1088}
1089
1090/*
1091 * Do the hard work of removing an element from the buddy allocator.
1092 * Call me with the zone->lock already held.
1093 */
1094static struct page *__rmqueue(struct zone *zone, unsigned int order,
1095                        int migratetype)
1096{
1097    struct page *page;
1098
1099retry_reserve:
1100    page = __rmqueue_smallest(zone, order, migratetype);
1101
1102    if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
1103        page = __rmqueue_fallback(zone, order, migratetype);
1104
1105        /*
1106         * Use MIGRATE_RESERVE rather than fail an allocation. goto
1107         * is used because __rmqueue_smallest is an inline function
1108         * and we want just one call site
1109         */
1110        if (!page) {
1111            migratetype = MIGRATE_RESERVE;
1112            goto retry_reserve;
1113        }
1114    }
1115
1116    trace_mm_page_alloc_zone_locked(page, order, migratetype);
1117    return page;
1118}
1119
1120/*
1121 * Obtain a specified number of elements from the buddy allocator, all under
1122 * a single hold of the lock, for efficiency. Add them to the supplied list.
1123 * Returns the number of new pages which were placed at *list.
1124 */
1125static int rmqueue_bulk(struct zone *zone, unsigned int order,
1126            unsigned long count, struct list_head *list,
1127            int migratetype, int cold)
1128{
1129    int mt = migratetype, i;
1130
1131    spin_lock(&zone->lock);
1132    for (i = 0; i < count; ++i) {
1133        struct page *page = __rmqueue(zone, order, migratetype);
1134        if (unlikely(page == NULL))
1135            break;
1136
1137        /*
1138         * Split buddy pages returned by expand() are received here
1139         * in physical page order. The page is added to the callers and
1140         * list and the list head then moves forward. From the callers
1141         * perspective, the linked list is ordered by page number in
1142         * some conditions. This is useful for IO devices that can
1143         * merge IO requests if the physical pages are ordered
1144         * properly.
1145         */
1146        if (likely(cold == 0))
1147            list_add(&page->lru, list);
1148        else
1149            list_add_tail(&page->lru, list);
1150        if (IS_ENABLED(CONFIG_CMA)) {
1151            mt = get_pageblock_migratetype(page);
1152            if (!is_migrate_cma(mt) && !is_migrate_isolate(mt))
1153                mt = migratetype;
1154        }
1155        set_freepage_migratetype(page, mt);
1156        list = &page->lru;
1157        if (is_migrate_cma(mt))
1158            __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
1159                          -(1 << order));
1160    }
1161    __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
1162    spin_unlock(&zone->lock);
1163    return i;
1164}
1165
1166#ifdef CONFIG_NUMA
1167/*
1168 * Called from the vmstat counter updater to drain pagesets of this
1169 * currently executing processor on remote nodes after they have
1170 * expired.
1171 *
1172 * Note that this function must be called with the thread pinned to
1173 * a single processor.
1174 */
1175void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
1176{
1177    unsigned long flags;
1178    int to_drain;
1179    unsigned long batch;
1180
1181    local_irq_save(flags);
1182    batch = ACCESS_ONCE(pcp->batch);
1183    if (pcp->count >= batch)
1184        to_drain = batch;
1185    else
1186        to_drain = pcp->count;
1187    if (to_drain > 0) {
1188        free_pcppages_bulk(zone, to_drain, pcp);
1189        pcp->count -= to_drain;
1190    }
1191    local_irq_restore(flags);
1192}
1193#endif
1194
1195/*
1196 * Drain pages of the indicated processor.
1197 *
1198 * The processor must either be the current processor and the
1199 * thread pinned to the current processor or a processor that
1200 * is not online.
1201 */
1202static void drain_pages(unsigned int cpu)
1203{
1204    unsigned long flags;
1205    struct zone *zone;
1206
1207    for_each_populated_zone(zone) {
1208        struct per_cpu_pageset *pset;
1209        struct per_cpu_pages *pcp;
1210
1211        local_irq_save(flags);
1212        pset = per_cpu_ptr(zone->pageset, cpu);
1213
1214        pcp = &pset->pcp;
1215        if (pcp->count) {
1216            free_pcppages_bulk(zone, pcp->count, pcp);
1217            pcp->count = 0;
1218        }
1219        local_irq_restore(flags);
1220    }
1221}
1222
1223/*
1224 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
1225 */
1226void drain_local_pages(void *arg)
1227{
1228    drain_pages(smp_processor_id());
1229}
1230
1231/*
1232 * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
1233 *
1234 * Note that this code is protected against sending an IPI to an offline
1235 * CPU but does not guarantee sending an IPI to newly hotplugged CPUs:
1236 * on_each_cpu_mask() blocks hotplug and won't talk to offlined CPUs but
1237 * nothing keeps CPUs from showing up after we populated the cpumask and
1238 * before the call to on_each_cpu_mask().
1239 */
1240void drain_all_pages(void)
1241{
1242    int cpu;
1243    struct per_cpu_pageset *pcp;
1244    struct zone *zone;
1245
1246    /*
1247     * Allocate in the BSS so we wont require allocation in
1248     * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
1249     */
1250    static cpumask_t cpus_with_pcps;
1251
1252    /*
1253     * We don't care about racing with CPU hotplug event
1254     * as offline notification will cause the notified
1255     * cpu to drain that CPU pcps and on_each_cpu_mask
1256     * disables preemption as part of its processing
1257     */
1258    for_each_online_cpu(cpu) {
1259        bool has_pcps = false;
1260        for_each_populated_zone(zone) {
1261            pcp = per_cpu_ptr(zone->pageset, cpu);
1262            if (pcp->pcp.count) {
1263                has_pcps = true;
1264                break;
1265            }
1266        }
1267        if (has_pcps)
1268            cpumask_set_cpu(cpu, &cpus_with_pcps);
1269        else
1270            cpumask_clear_cpu(cpu, &cpus_with_pcps);
1271    }
1272    on_each_cpu_mask(&cpus_with_pcps, drain_local_pages, NULL, 1);
1273}
1274
1275#ifdef CONFIG_HIBERNATION
1276
1277void mark_free_pages(struct zone *zone)
1278{
1279    unsigned long pfn, max_zone_pfn;
1280    unsigned long flags;
1281    int order, t;
1282    struct list_head *curr;
1283
1284    if (!zone->spanned_pages)
1285        return;
1286
1287    spin_lock_irqsave(&zone->lock, flags);
1288
1289    max_zone_pfn = zone_end_pfn(zone);
1290    for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1291        if (pfn_valid(pfn)) {
1292            struct page *page = pfn_to_page(pfn);
1293
1294            if (!swsusp_page_is_forbidden(page))
1295                swsusp_unset_page_free(page);
1296        }
1297
1298    for_each_migratetype_order(order, t) {
1299        list_for_each(curr, &zone->free_area[order].free_list[t]) {
1300            unsigned long i;
1301
1302            pfn = page_to_pfn(list_entry(curr, struct page, lru));
1303            for (i = 0; i < (1UL << order); i++)
1304                swsusp_set_page_free(pfn_to_page(pfn + i));
1305        }
1306    }
1307    spin_unlock_irqrestore(&zone->lock, flags);
1308}
1309#endif /* CONFIG_PM */
1310
1311/*
1312 * Free a 0-order page
1313 * cold == 1 ? free a cold page : free a hot page
1314 */
1315void free_hot_cold_page(struct page *page, int cold)
1316{
1317    struct zone *zone = page_zone(page);
1318    struct per_cpu_pages *pcp;
1319    unsigned long flags;
1320    int migratetype;
1321
1322    if (!free_pages_prepare(page, 0))
1323        return;
1324
1325    migratetype = get_pageblock_migratetype(page);
1326    set_freepage_migratetype(page, migratetype);
1327    local_irq_save(flags);
1328    __count_vm_event(PGFREE);
1329
1330    /*
1331     * We only track unmovable, reclaimable and movable on pcp lists.
1332     * Free ISOLATE pages back to the allocator because they are being
1333     * offlined but treat RESERVE as movable pages so we can get those
1334     * areas back if necessary. Otherwise, we may have to free
1335     * excessively into the page allocator
1336     */
1337    if (migratetype >= MIGRATE_PCPTYPES) {
1338        if (unlikely(is_migrate_isolate(migratetype))) {
1339            free_one_page(zone, page, 0, migratetype);
1340            goto out;
1341        }
1342        migratetype = MIGRATE_MOVABLE;
1343    }
1344
1345    pcp = &this_cpu_ptr(zone->pageset)->pcp;
1346    if (cold)
1347        list_add_tail(&page->lru, &pcp->lists[migratetype]);
1348    else
1349        list_add(&page->lru, &pcp->lists[migratetype]);
1350    pcp->count++;
1351    if (pcp->count >= pcp->high) {
1352        unsigned long batch = ACCESS_ONCE(pcp->batch);
1353        free_pcppages_bulk(zone, batch, pcp);
1354        pcp->count -= batch;
1355    }
1356
1357out:
1358    local_irq_restore(flags);
1359}
1360
1361/*
1362 * Free a list of 0-order pages
1363 */
1364void free_hot_cold_page_list(struct list_head *list, int cold)
1365{
1366    struct page *page, *next;
1367
1368    list_for_each_entry_safe(page, next, list, lru) {
1369        trace_mm_page_free_batched(page, cold);
1370        free_hot_cold_page(page, cold);
1371    }
1372}
1373
1374/*
1375 * split_page takes a non-compound higher-order page, and splits it into
1376 * n (1<<order) sub-pages: page[0..n]
1377 * Each sub-page must be freed individually.
1378 *
1379 * Note: this is probably too low level an operation for use in drivers.
1380 * Please consult with lkml before using this in your driver.
1381 */
1382void split_page(struct page *page, unsigned int order)
1383{
1384    int i;
1385
1386    VM_BUG_ON(PageCompound(page));
1387    VM_BUG_ON(!page_count(page));
1388
1389#ifdef CONFIG_KMEMCHECK
1390    /*
1391     * Split shadow pages too, because free(page[0]) would
1392     * otherwise free the whole shadow.
1393     */
1394    if (kmemcheck_page_is_tracked(page))
1395        split_page(virt_to_page(page[0].shadow), order);
1396#endif
1397
1398    for (i = 1; i < (1 << order); i++)
1399        set_page_refcounted(page + i);
1400}
1401EXPORT_SYMBOL_GPL(split_page);
1402
1403static int __isolate_free_page(struct page *page, unsigned int order)
1404{
1405    unsigned long watermark;
1406    struct zone *zone;
1407    int mt;
1408
1409    BUG_ON(!PageBuddy(page));
1410
1411    zone = page_zone(page);
1412    mt = get_pageblock_migratetype(page);
1413
1414    if (!is_migrate_isolate(mt)) {
1415        /* Obey watermarks as if the page was being allocated */
1416        watermark = low_wmark_pages(zone) + (1 << order);
1417        if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
1418            return 0;
1419
1420        __mod_zone_freepage_state(zone, -(1UL << order), mt);
1421    }
1422
1423    /* Remove page from free list */
1424    list_del(&page->lru);
1425    zone->free_area[order].nr_free--;
1426    rmv_page_order(page);
1427
1428    /* Set the pageblock if the isolated page is at least a pageblock */
1429    if (order >= pageblock_order - 1) {
1430        struct page *endpage = page + (1 << order) - 1;
1431        for (; page < endpage; page += pageblock_nr_pages) {
1432            int mt = get_pageblock_migratetype(page);
1433            if (!is_migrate_isolate(mt) && !is_migrate_cma(mt))
1434                set_pageblock_migratetype(page,
1435                              MIGRATE_MOVABLE);
1436        }
1437    }
1438
1439    return 1UL << order;
1440}
1441
1442/*
1443 * Similar to split_page except the page is already free. As this is only
1444 * being used for migration, the migratetype of the block also changes.
1445 * As this is called with interrupts disabled, the caller is responsible
1446 * for calling arch_alloc_page() and kernel_map_page() after interrupts
1447 * are enabled.
1448 *
1449 * Note: this is probably too low level an operation for use in drivers.
1450 * Please consult with lkml before using this in your driver.
1451 */
1452int split_free_page(struct page *page)
1453{
1454    unsigned int order;
1455    int nr_pages;
1456
1457    order = page_order(page);
1458
1459    nr_pages = __isolate_free_page(page, order);
1460    if (!nr_pages)
1461        return 0;
1462
1463    /* Split into individual pages */
1464    set_page_refcounted(page);
1465    split_page(page, order);
1466    return nr_pages;
1467}
1468
1469/*
1470 * Really, prep_compound_page() should be called from __rmqueue_bulk(). But
1471 * we cheat by calling it from here, in the order > 0 path. Saves a branch
1472 * or two.
1473 */
1474static inline
1475struct page *buffered_rmqueue(struct zone *preferred_zone,
1476            struct zone *zone, int order, gfp_t gfp_flags,
1477            int migratetype)
1478{
1479    unsigned long flags;
1480    struct page *page;
1481    int cold = !!(gfp_flags & __GFP_COLD);
1482
1483again:
1484    if (likely(order == 0)) {
1485        struct per_cpu_pages *pcp;
1486        struct list_head *list;
1487
1488        local_irq_save(flags);
1489        pcp = &this_cpu_ptr(zone->pageset)->pcp;
1490        list = &pcp->lists[migratetype];
1491        if (list_empty(list)) {
1492            pcp->count += rmqueue_bulk(zone, 0,
1493                    pcp->batch, list,
1494                    migratetype, cold);
1495            if (unlikely(list_empty(list)))
1496                goto failed;
1497        }
1498
1499        if (cold)
1500            page = list_entry(list->prev, struct page, lru);
1501        else
1502            page = list_entry(list->next, struct page, lru);
1503
1504        list_del(&page->lru);
1505        pcp->count--;
1506    } else {
1507        if (unlikely(gfp_flags & __GFP_NOFAIL)) {
1508            /*
1509             * __GFP_NOFAIL is not to be used in new code.
1510             *
1511             * All __GFP_NOFAIL callers should be fixed so that they
1512             * properly detect and handle allocation failures.
1513             *
1514             * We most definitely don't want callers attempting to
1515             * allocate greater than order-1 page units with
1516             * __GFP_NOFAIL.
1517             */
1518            WARN_ON_ONCE(order > 1);
1519        }
1520        spin_lock_irqsave(&zone->lock, flags);
1521        page = __rmqueue(zone, order, migratetype);
1522        spin_unlock(&zone->lock);
1523        if (!page)
1524            goto failed;
1525        __mod_zone_freepage_state(zone, -(1 << order),
1526                      get_pageblock_migratetype(page));
1527    }
1528
1529    __count_zone_vm_events(PGALLOC, zone, 1 << order);
1530    zone_statistics(preferred_zone, zone, gfp_flags);
1531    local_irq_restore(flags);
1532
1533    VM_BUG_ON(bad_range(zone, page));
1534    if (prep_new_page(page, order, gfp_flags))
1535        goto again;
1536    return page;
1537
1538failed:
1539    local_irq_restore(flags);
1540    return NULL;
1541}
1542
1543#ifdef CONFIG_FAIL_PAGE_ALLOC
1544
1545static struct {
1546    struct fault_attr attr;
1547
1548    u32 ignore_gfp_highmem;
1549    u32 ignore_gfp_wait;
1550    u32 min_order;
1551} fail_page_alloc = {
1552    .attr = FAULT_ATTR_INITIALIZER,
1553    .ignore_gfp_wait = 1,
1554    .ignore_gfp_highmem = 1,
1555    .min_order = 1,
1556};
1557
1558static int __init setup_fail_page_alloc(char *str)
1559{
1560    return setup_fault_attr(&fail_page_alloc.attr, str);
1561}
1562__setup("fail_page_alloc=", setup_fail_page_alloc);
1563
1564static bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1565{
1566    if (order < fail_page_alloc.min_order)
1567        return false;
1568    if (gfp_mask & __GFP_NOFAIL)
1569        return false;
1570    if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1571        return false;
1572    if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1573        return false;
1574
1575    return should_fail(&fail_page_alloc.attr, 1 << order);
1576}
1577
1578#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1579
1580static int __init fail_page_alloc_debugfs(void)
1581{
1582    umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1583    struct dentry *dir;
1584
1585    dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
1586                    &fail_page_alloc.attr);
1587    if (IS_ERR(dir))
1588        return PTR_ERR(dir);
1589
1590    if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
1591                &fail_page_alloc.ignore_gfp_wait))
1592        goto fail;
1593    if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1594                &fail_page_alloc.ignore_gfp_highmem))
1595        goto fail;
1596    if (!debugfs_create_u32("min-order", mode, dir,
1597                &fail_page_alloc.min_order))
1598        goto fail;
1599
1600    return 0;
1601fail:
1602    debugfs_remove_recursive(dir);
1603
1604    return -ENOMEM;
1605}
1606
1607late_initcall(fail_page_alloc_debugfs);
1608
1609#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1610
1611#else /* CONFIG_FAIL_PAGE_ALLOC */
1612
1613static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1614{
1615    return false;
1616}
1617
1618#endif /* CONFIG_FAIL_PAGE_ALLOC */
1619
1620/*
1621 * Return true if free pages are above 'mark'. This takes into account the order
1622 * of the allocation.
1623 */
1624static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1625              int classzone_idx, int alloc_flags, long free_pages)
1626{
1627    /* free_pages my go negative - that's OK */
1628    long min = mark;
1629    long lowmem_reserve = z->lowmem_reserve[classzone_idx];
1630    int o;
1631    long free_cma = 0;
1632
1633    free_pages -= (1 << order) - 1;
1634    if (alloc_flags & ALLOC_HIGH)
1635        min -= min / 2;
1636    if (alloc_flags & ALLOC_HARDER)
1637        min -= min / 4;
1638#ifdef CONFIG_CMA
1639    /* If allocation can't use CMA areas don't use free CMA pages */
1640    if (!(alloc_flags & ALLOC_CMA))
1641        free_cma = zone_page_state(z, NR_FREE_CMA_PAGES);
1642#endif
1643
1644    if (free_pages - free_cma <= min + lowmem_reserve)
1645        return false;
1646    for (o = 0; o < order; o++) {
1647        /* At the next order, this order's pages become unavailable */
1648        free_pages -= z->free_area[o].nr_free << o;
1649
1650        /* Require fewer higher order pages to be free */
1651        min >>= 1;
1652
1653        if (free_pages <= min)
1654            return false;
1655    }
1656    return true;
1657}
1658
1659bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1660              int classzone_idx, int alloc_flags)
1661{
1662    return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1663                    zone_page_state(z, NR_FREE_PAGES));
1664}
1665
1666bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark,
1667              int classzone_idx, int alloc_flags)
1668{
1669    long free_pages = zone_page_state(z, NR_FREE_PAGES);
1670
1671    if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
1672        free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
1673
1674    return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1675                                free_pages);
1676}
1677
1678#ifdef CONFIG_NUMA
1679/*
1680 * zlc_setup - Setup for "zonelist cache". Uses cached zone data to
1681 * skip over zones that are not allowed by the cpuset, or that have
1682 * been recently (in last second) found to be nearly full. See further
1683 * comments in mmzone.h. Reduces cache footprint of zonelist scans
1684 * that have to skip over a lot of full or unallowed zones.
1685 *
1686 * If the zonelist cache is present in the passed in zonelist, then
1687 * returns a pointer to the allowed node mask (either the current
1688 * tasks mems_allowed, or node_states[N_MEMORY].)
1689 *
1690 * If the zonelist cache is not available for this zonelist, does
1691 * nothing and returns NULL.
1692 *
1693 * If the fullzones BITMAP in the zonelist cache is stale (more than
1694 * a second since last zap'd) then we zap it out (clear its bits.)
1695 *
1696 * We hold off even calling zlc_setup, until after we've checked the
1697 * first zone in the zonelist, on the theory that most allocations will
1698 * be satisfied from that first zone, so best to examine that zone as
1699 * quickly as we can.
1700 */
1701static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1702{
1703    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1704    nodemask_t *allowednodes; /* zonelist_cache approximation */
1705
1706    zlc = zonelist->zlcache_ptr;
1707    if (!zlc)
1708        return NULL;
1709
1710    if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1711        bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1712        zlc->last_full_zap = jiffies;
1713    }
1714
1715    allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1716                    &cpuset_current_mems_allowed :
1717                    &node_states[N_MEMORY];
1718    return allowednodes;
1719}
1720
1721/*
1722 * Given 'z' scanning a zonelist, run a couple of quick checks to see
1723 * if it is worth looking at further for free memory:
1724 * 1) Check that the zone isn't thought to be full (doesn't have its
1725 * bit set in the zonelist_cache fullzones BITMAP).
1726 * 2) Check that the zones node (obtained from the zonelist_cache
1727 * z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1728 * Return true (non-zero) if zone is worth looking at further, or
1729 * else return false (zero) if it is not.
1730 *
1731 * This check -ignores- the distinction between various watermarks,
1732 * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ... If a zone is
1733 * found to be full for any variation of these watermarks, it will
1734 * be considered full for up to one second by all requests, unless
1735 * we are so low on memory on all allowed nodes that we are forced
1736 * into the second scan of the zonelist.
1737 *
1738 * In the second scan we ignore this zonelist cache and exactly
1739 * apply the watermarks to all zones, even it is slower to do so.
1740 * We are low on memory in the second scan, and should leave no stone
1741 * unturned looking for a free page.
1742 */
1743static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1744                        nodemask_t *allowednodes)
1745{
1746    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1747    int i; /* index of *z in zonelist zones */
1748    int n; /* node that zone *z is on */
1749
1750    zlc = zonelist->zlcache_ptr;
1751    if (!zlc)
1752        return 1;
1753
1754    i = z - zonelist->_zonerefs;
1755    n = zlc->z_to_n[i];
1756
1757    /* This zone is worth trying if it is allowed but not full */
1758    return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1759}
1760
1761/*
1762 * Given 'z' scanning a zonelist, set the corresponding bit in
1763 * zlc->fullzones, so that subsequent attempts to allocate a page
1764 * from that zone don't waste time re-examining it.
1765 */
1766static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1767{
1768    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1769    int i; /* index of *z in zonelist zones */
1770
1771    zlc = zonelist->zlcache_ptr;
1772    if (!zlc)
1773        return;
1774
1775    i = z - zonelist->_zonerefs;
1776
1777    set_bit(i, zlc->fullzones);
1778}
1779
1780/*
1781 * clear all zones full, called after direct reclaim makes progress so that
1782 * a zone that was recently full is not skipped over for up to a second
1783 */
1784static void zlc_clear_zones_full(struct zonelist *zonelist)
1785{
1786    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1787
1788    zlc = zonelist->zlcache_ptr;
1789    if (!zlc)
1790        return;
1791
1792    bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1793}
1794
1795static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
1796{
1797    return node_isset(local_zone->node, zone->zone_pgdat->reclaim_nodes);
1798}
1799
1800static void __paginginit init_zone_allows_reclaim(int nid)
1801{
1802    int i;
1803
1804    for_each_online_node(i)
1805        if (node_distance(nid, i) <= RECLAIM_DISTANCE)
1806            node_set(i, NODE_DATA(nid)->reclaim_nodes);
1807        else
1808            zone_reclaim_mode = 1;
1809}
1810
1811#else /* CONFIG_NUMA */
1812
1813static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1814{
1815    return NULL;
1816}
1817
1818static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1819                nodemask_t *allowednodes)
1820{
1821    return 1;
1822}
1823
1824static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1825{
1826}
1827
1828static void zlc_clear_zones_full(struct zonelist *zonelist)
1829{
1830}
1831
1832static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
1833{
1834    return true;
1835}
1836
1837static inline void init_zone_allows_reclaim(int nid)
1838{
1839}
1840#endif /* CONFIG_NUMA */
1841
1842/*
1843 * get_page_from_freelist goes through the zonelist trying to allocate
1844 * a page.
1845 */
1846static struct page *
1847get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1848        struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
1849        struct zone *preferred_zone, int migratetype)
1850{
1851    struct zoneref *z;
1852    struct page *page = NULL;
1853    int classzone_idx;
1854    struct zone *zone;
1855    nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1856    int zlc_active = 0; /* set if using zonelist_cache */
1857    int did_zlc_setup = 0; /* just call zlc_setup() one time */
1858
1859    classzone_idx = zone_idx(preferred_zone);
1860zonelist_scan:
1861    /*
1862     * Scan zonelist, looking for a zone with enough free.
1863     * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1864     */
1865    for_each_zone_zonelist_nodemask(zone, z, zonelist,
1866                        high_zoneidx, nodemask) {
1867        if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
1868            !zlc_zone_worth_trying(zonelist, z, allowednodes))
1869                continue;
1870        if ((alloc_flags & ALLOC_CPUSET) &&
1871            !cpuset_zone_allowed_softwall(zone, gfp_mask))
1872                continue;
1873        /*
1874         * When allocating a page cache page for writing, we
1875         * want to get it from a zone that is within its dirty
1876         * limit, such that no single zone holds more than its
1877         * proportional share of globally allowed dirty pages.
1878         * The dirty limits take into account the zone's
1879         * lowmem reserves and high watermark so that kswapd
1880         * should be able to balance it without having to
1881         * write pages from its LRU list.
1882         *
1883         * This may look like it could increase pressure on
1884         * lower zones by failing allocations in higher zones
1885         * before they are full. But the pages that do spill
1886         * over are limited as the lower zones are protected
1887         * by this very same mechanism. It should not become
1888         * a practical burden to them.
1889         *
1890         * XXX: For now, allow allocations to potentially
1891         * exceed the per-zone dirty limit in the slowpath
1892         * (ALLOC_WMARK_LOW unset) before going into reclaim,
1893         * which is important when on a NUMA setup the allowed
1894         * zones are together not big enough to reach the
1895         * global limit. The proper fix for these situations
1896         * will require awareness of zones in the
1897         * dirty-throttling and the flusher threads.
1898         */
1899        if ((alloc_flags & ALLOC_WMARK_LOW) &&
1900            (gfp_mask & __GFP_WRITE) && !zone_dirty_ok(zone))
1901            goto this_zone_full;
1902
1903        BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
1904        if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
1905            unsigned long mark;
1906            int ret;
1907
1908            mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
1909            if (zone_watermark_ok(zone, order, mark,
1910                    classzone_idx, alloc_flags))
1911                goto try_this_zone;
1912
1913            if (IS_ENABLED(CONFIG_NUMA) &&
1914                    !did_zlc_setup && nr_online_nodes > 1) {
1915                /*
1916                 * we do zlc_setup if there are multiple nodes
1917                 * and before considering the first zone allowed
1918                 * by the cpuset.
1919                 */
1920                allowednodes = zlc_setup(zonelist, alloc_flags);
1921                zlc_active = 1;
1922                did_zlc_setup = 1;
1923            }
1924
1925            if (zone_reclaim_mode == 0 ||
1926                !zone_allows_reclaim(preferred_zone, zone))
1927                goto this_zone_full;
1928
1929            /*
1930             * As we may have just activated ZLC, check if the first
1931             * eligible zone has failed zone_reclaim recently.
1932             */
1933            if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
1934                !zlc_zone_worth_trying(zonelist, z, allowednodes))
1935                continue;
1936
1937            ret = zone_reclaim(zone, gfp_mask, order);
1938            switch (ret) {
1939            case ZONE_RECLAIM_NOSCAN:
1940                /* did not scan */
1941                continue;
1942            case ZONE_RECLAIM_FULL:
1943                /* scanned but unreclaimable */
1944                continue;
1945            default:
1946                /* did we reclaim enough */
1947                if (zone_watermark_ok(zone, order, mark,
1948                        classzone_idx, alloc_flags))
1949                    goto try_this_zone;
1950
1951                /*
1952                 * Failed to reclaim enough to meet watermark.
1953                 * Only mark the zone full if checking the min
1954                 * watermark or if we failed to reclaim just
1955                 * 1<<order pages or else the page allocator
1956                 * fastpath will prematurely mark zones full
1957                 * when the watermark is between the low and
1958                 * min watermarks.
1959                 */
1960                if (((alloc_flags & ALLOC_WMARK_MASK) == ALLOC_WMARK_MIN) ||
1961                    ret == ZONE_RECLAIM_SOME)
1962                    goto this_zone_full;
1963
1964                continue;
1965            }
1966        }
1967
1968try_this_zone:
1969        page = buffered_rmqueue(preferred_zone, zone, order,
1970                        gfp_mask, migratetype);
1971        if (page)
1972            break;
1973this_zone_full:
1974        if (IS_ENABLED(CONFIG_NUMA))
1975            zlc_mark_zone_full(zonelist, z);
1976    }
1977
1978    if (unlikely(IS_ENABLED(CONFIG_NUMA) && page == NULL && zlc_active)) {
1979        /* Disable zlc cache for second zonelist scan */
1980        zlc_active = 0;
1981        goto zonelist_scan;
1982    }
1983
1984    if (page)
1985        /*
1986         * page->pfmemalloc is set when ALLOC_NO_WATERMARKS was
1987         * necessary to allocate the page. The expectation is
1988         * that the caller is taking steps that will free more
1989         * memory. The caller should avoid the page being used
1990         * for !PFMEMALLOC purposes.
1991         */
1992        page->pfmemalloc = !!(alloc_flags & ALLOC_NO_WATERMARKS);
1993
1994    return page;
1995}
1996
1997/*
1998 * Large machines with many possible nodes should not always dump per-node
1999 * meminfo in irq context.
2000 */
2001static inline bool should_suppress_show_mem(void)
2002{
2003    bool ret = false;
2004
2005#if NODES_SHIFT > 8
2006    ret = in_interrupt();
2007#endif
2008    return ret;
2009}
2010
2011static DEFINE_RATELIMIT_STATE(nopage_rs,
2012        DEFAULT_RATELIMIT_INTERVAL,
2013        DEFAULT_RATELIMIT_BURST);
2014
2015void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...)
2016{
2017    unsigned int filter = SHOW_MEM_FILTER_NODES;
2018
2019    if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) ||
2020        debug_guardpage_minorder() > 0)
2021        return;
2022
2023    /*
2024     * Walking all memory to count page types is very expensive and should
2025     * be inhibited in non-blockable contexts.
2026     */
2027    if (!(gfp_mask & __GFP_WAIT))
2028        filter |= SHOW_MEM_FILTER_PAGE_COUNT;
2029
2030    /*
2031     * This documents exceptions given to allocations in certain
2032     * contexts that are allowed to allocate outside current's set
2033     * of allowed nodes.
2034     */
2035    if (!(gfp_mask & __GFP_NOMEMALLOC))
2036        if (test_thread_flag(TIF_MEMDIE) ||
2037            (current->flags & (PF_MEMALLOC | PF_EXITING)))
2038            filter &= ~SHOW_MEM_FILTER_NODES;
2039    if (in_interrupt() || !(gfp_mask & __GFP_WAIT))
2040        filter &= ~SHOW_MEM_FILTER_NODES;
2041
2042    if (fmt) {
2043        struct va_format vaf;
2044        va_list args;
2045
2046        va_start(args, fmt);
2047
2048        vaf.fmt = fmt;
2049        vaf.va = &args;
2050
2051        pr_warn("%pV", &vaf);
2052
2053        va_end(args);
2054    }
2055
2056    pr_warn("%s: page allocation failure: order:%d, mode:0x%x\n",
2057        current->comm, order, gfp_mask);
2058
2059    dump_stack();
2060    if (!should_suppress_show_mem())
2061        show_mem(filter);
2062}
2063
2064static inline int
2065should_alloc_retry(gfp_t gfp_mask, unsigned int order,
2066                unsigned long did_some_progress,
2067                unsigned long pages_reclaimed)
2068{
2069    /* Do not loop if specifically requested */
2070    if (gfp_mask & __GFP_NORETRY)
2071        return 0;
2072
2073    /* Always retry if specifically requested */
2074    if (gfp_mask & __GFP_NOFAIL)
2075        return 1;
2076
2077    /*
2078     * Suspend converts GFP_KERNEL to __GFP_WAIT which can prevent reclaim
2079     * making forward progress without invoking OOM. Suspend also disables
2080     * storage devices so kswapd will not help. Bail if we are suspending.
2081     */
2082    if (!did_some_progress && pm_suspended_storage())
2083        return 0;
2084
2085    /*
2086     * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
2087     * means __GFP_NOFAIL, but that may not be true in other
2088     * implementations.
2089     */
2090    if (order <= PAGE_ALLOC_COSTLY_ORDER)
2091        return 1;
2092
2093    /*
2094     * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
2095     * specified, then we retry until we no longer reclaim any pages
2096     * (above), or we've reclaimed an order of pages at least as
2097     * large as the allocation's order. In both cases, if the
2098     * allocation still fails, we stop retrying.
2099     */
2100    if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
2101        return 1;
2102
2103    return 0;
2104}
2105
2106static inline struct page *
2107__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
2108    struct zonelist *zonelist, enum zone_type high_zoneidx,
2109    nodemask_t *nodemask, struct zone *preferred_zone,
2110    int migratetype)
2111{
2112    struct page *page;
2113
2114    /* Acquire the OOM killer lock for the zones in zonelist */
2115    if (!try_set_zonelist_oom(zonelist, gfp_mask)) {
2116        schedule_timeout_uninterruptible(1);
2117        return NULL;
2118    }
2119
2120    /*
2121     * Go through the zonelist yet one more time, keep very high watermark
2122     * here, this is only to catch a parallel oom killing, we must fail if
2123     * we're still under heavy pressure.
2124     */
2125    page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
2126        order, zonelist, high_zoneidx,
2127        ALLOC_WMARK_HIGH|ALLOC_CPUSET,
2128        preferred_zone, migratetype);
2129    if (page)
2130        goto out;
2131
2132    if (!(gfp_mask & __GFP_NOFAIL)) {
2133        /* The OOM killer will not help higher order allocs */
2134        if (order > PAGE_ALLOC_COSTLY_ORDER)
2135            goto out;
2136        /* The OOM killer does not needlessly kill tasks for lowmem */
2137        if (high_zoneidx < ZONE_NORMAL)
2138            goto out;
2139        /*
2140         * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
2141         * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
2142         * The caller should handle page allocation failure by itself if
2143         * it specifies __GFP_THISNODE.
2144         * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
2145         */
2146        if (gfp_mask & __GFP_THISNODE)
2147            goto out;
2148    }
2149    /* Exhausted what can be done so it's blamo time */
2150    out_of_memory(zonelist, gfp_mask, order, nodemask, false);
2151
2152out:
2153    clear_zonelist_oom(zonelist, gfp_mask);
2154    return page;
2155}
2156
2157#ifdef CONFIG_COMPACTION
2158/* Try memory compaction for high-order allocations before reclaim */
2159static struct page *
2160__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2161    struct zonelist *zonelist, enum zone_type high_zoneidx,
2162    nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2163    int migratetype, bool sync_migration,
2164    bool *contended_compaction, bool *deferred_compaction,
2165    unsigned long *did_some_progress)
2166{
2167    if (!order)
2168        return NULL;
2169
2170    if (compaction_deferred(preferred_zone, order)) {
2171        *deferred_compaction = true;
2172        return NULL;
2173    }
2174
2175    current->flags |= PF_MEMALLOC;
2176    *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
2177                        nodemask, sync_migration,
2178                        contended_compaction);
2179    current->flags &= ~PF_MEMALLOC;
2180
2181    if (*did_some_progress != COMPACT_SKIPPED) {
2182        struct page *page;
2183
2184        /* Page migration frees to the PCP lists but we want merging */
2185        drain_pages(get_cpu());
2186        put_cpu();
2187
2188        page = get_page_from_freelist(gfp_mask, nodemask,
2189                order, zonelist, high_zoneidx,
2190                alloc_flags & ~ALLOC_NO_WATERMARKS,
2191                preferred_zone, migratetype);
2192        if (page) {
2193            preferred_zone->compact_blockskip_flush = false;
2194            preferred_zone->compact_considered = 0;
2195            preferred_zone->compact_defer_shift = 0;
2196            if (order >= preferred_zone->compact_order_failed)
2197                preferred_zone->compact_order_failed = order + 1;
2198            count_vm_event(COMPACTSUCCESS);
2199            return page;
2200        }
2201
2202        /*
2203         * It's bad if compaction run occurs and fails.
2204         * The most likely reason is that pages exist,
2205         * but not enough to satisfy watermarks.
2206         */
2207        count_vm_event(COMPACTFAIL);
2208
2209        /*
2210         * As async compaction considers a subset of pageblocks, only
2211         * defer if the failure was a sync compaction failure.
2212         */
2213        if (sync_migration)
2214            defer_compaction(preferred_zone, order);
2215
2216        cond_resched();
2217    }
2218
2219    return NULL;
2220}
2221#else
2222static inline struct page *
2223__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2224    struct zonelist *zonelist, enum zone_type high_zoneidx,
2225    nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2226    int migratetype, bool sync_migration,
2227    bool *contended_compaction, bool *deferred_compaction,
2228    unsigned long *did_some_progress)
2229{
2230    return NULL;
2231}
2232#endif /* CONFIG_COMPACTION */
2233
2234/* Perform direct synchronous page reclaim */
2235static int
2236__perform_reclaim(gfp_t gfp_mask, unsigned int order, struct zonelist *zonelist,
2237          nodemask_t *nodemask)
2238{
2239    struct reclaim_state reclaim_state;
2240    int progress;
2241
2242    cond_resched();
2243
2244    /* We now go into synchronous reclaim */
2245    cpuset_memory_pressure_bump();
2246    current->flags |= PF_MEMALLOC;
2247    lockdep_set_current_reclaim_state(gfp_mask);
2248    reclaim_state.reclaimed_slab = 0;
2249    current->reclaim_state = &reclaim_state;
2250
2251    progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
2252
2253    current->reclaim_state = NULL;
2254    lockdep_clear_current_reclaim_state();
2255    current->flags &= ~PF_MEMALLOC;
2256
2257    cond_resched();
2258
2259    return progress;
2260}
2261
2262/* The really slow allocator path where we enter direct reclaim */
2263static inline struct page *
2264__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
2265    struct zonelist *zonelist, enum zone_type high_zoneidx,
2266    nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2267    int migratetype, unsigned long *did_some_progress)
2268{
2269    struct page *page = NULL;
2270    bool drained = false;
2271
2272    *did_some_progress = __perform_reclaim(gfp_mask, order, zonelist,
2273                           nodemask);
2274    if (unlikely(!(*did_some_progress)))
2275        return NULL;
2276
2277    /* After successful reclaim, reconsider all zones for allocation */
2278    if (IS_ENABLED(CONFIG_NUMA))
2279        zlc_clear_zones_full(zonelist);
2280
2281retry:
2282    page = get_page_from_freelist(gfp_mask, nodemask, order,
2283                    zonelist, high_zoneidx,
2284                    alloc_flags & ~ALLOC_NO_WATERMARKS,
2285                    preferred_zone, migratetype);
2286
2287    /*
2288     * If an allocation failed after direct reclaim, it could be because
2289     * pages are pinned on the per-cpu lists. Drain them and try again
2290     */
2291    if (!page && !drained) {
2292        drain_all_pages();
2293        drained = true;
2294        goto retry;
2295    }
2296
2297    return page;
2298}
2299
2300/*
2301 * This is called in the allocator slow-path if the allocation request is of
2302 * sufficient urgency to ignore watermarks and take other desperate measures
2303 */
2304static inline struct page *
2305__alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
2306    struct zonelist *zonelist, enum zone_type high_zoneidx,
2307    nodemask_t *nodemask, struct zone *preferred_zone,
2308    int migratetype)
2309{
2310    struct page *page;
2311
2312    do {
2313        page = get_page_from_freelist(gfp_mask, nodemask, order,
2314            zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
2315            preferred_zone, migratetype);
2316
2317        if (!page && gfp_mask & __GFP_NOFAIL)
2318            wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2319    } while (!page && (gfp_mask & __GFP_NOFAIL));
2320
2321    return page;
2322}
2323
2324static inline
2325void wake_all_kswapd(unsigned int order, struct zonelist *zonelist,
2326                        enum zone_type high_zoneidx,
2327                        enum zone_type classzone_idx)
2328{
2329    struct zoneref *z;
2330    struct zone *zone;
2331
2332    for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
2333        wakeup_kswapd(zone, order, classzone_idx);
2334}
2335
2336static inline int
2337gfp_to_alloc_flags(gfp_t gfp_mask)
2338{
2339    int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
2340    const gfp_t wait = gfp_mask & __GFP_WAIT;
2341
2342    /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
2343    BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
2344
2345    /*
2346     * The caller may dip into page reserves a bit more if the caller
2347     * cannot run direct reclaim, or if the caller has realtime scheduling
2348     * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
2349     * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
2350     */
2351    alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
2352
2353    if (!wait) {
2354        /*
2355         * Not worth trying to allocate harder for
2356         * __GFP_NOMEMALLOC even if it can't schedule.
2357         */
2358        if (!(gfp_mask & __GFP_NOMEMALLOC))
2359            alloc_flags |= ALLOC_HARDER;
2360        /*
2361         * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
2362         * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
2363         */
2364        alloc_flags &= ~ALLOC_CPUSET;
2365    } else if (unlikely(rt_task(current)) && !in_interrupt())
2366        alloc_flags |= ALLOC_HARDER;
2367
2368    if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
2369        if (gfp_mask & __GFP_MEMALLOC)
2370            alloc_flags |= ALLOC_NO_WATERMARKS;
2371        else if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
2372            alloc_flags |= ALLOC_NO_WATERMARKS;
2373        else if (!in_interrupt() &&
2374                ((current->flags & PF_MEMALLOC) ||
2375                 unlikely(test_thread_flag(TIF_MEMDIE))))
2376            alloc_flags |= ALLOC_NO_WATERMARKS;
2377    }
2378#ifdef CONFIG_CMA
2379    if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
2380        alloc_flags |= ALLOC_CMA;
2381#endif
2382    return alloc_flags;
2383}
2384
2385bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
2386{
2387    return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_NO_WATERMARKS);
2388}
2389
2390static inline struct page *
2391__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
2392    struct zonelist *zonelist, enum zone_type high_zoneidx,
2393    nodemask_t *nodemask, struct zone *preferred_zone,
2394    int migratetype)
2395{
2396    const gfp_t wait = gfp_mask & __GFP_WAIT;
2397    struct page *page = NULL;
2398    int alloc_flags;
2399    unsigned long pages_reclaimed = 0;
2400    unsigned long did_some_progress;
2401    bool sync_migration = false;
2402    bool deferred_compaction = false;
2403    bool contended_compaction = false;
2404
2405    /*
2406     * In the slowpath, we sanity check order to avoid ever trying to
2407     * reclaim >= MAX_ORDER areas which will never succeed. Callers may
2408     * be using allocators in order of preference for an area that is
2409     * too large.
2410     */
2411    if (order >= MAX_ORDER) {
2412        WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
2413        return NULL;
2414    }
2415
2416    /*
2417     * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
2418     * __GFP_NOWARN set) should not cause reclaim since the subsystem
2419     * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
2420     * using a larger set of nodes after it has established that the
2421     * allowed per node queues are empty and that nodes are
2422     * over allocated.
2423     */
2424    if (IS_ENABLED(CONFIG_NUMA) &&
2425            (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
2426        goto nopage;
2427
2428restart:
2429    if (!(gfp_mask & __GFP_NO_KSWAPD))
2430        wake_all_kswapd(order, zonelist, high_zoneidx,
2431                        zone_idx(preferred_zone));
2432
2433    /*
2434     * OK, we're below the kswapd watermark and have kicked background
2435     * reclaim. Now things get more complex, so set up alloc_flags according
2436     * to how we want to proceed.
2437     */
2438    alloc_flags = gfp_to_alloc_flags(gfp_mask);
2439
2440    /*
2441     * Find the true preferred zone if the allocation is unconstrained by
2442     * cpusets.
2443     */
2444    if (!(alloc_flags & ALLOC_CPUSET) && !nodemask)
2445        first_zones_zonelist(zonelist, high_zoneidx, NULL,
2446                    &preferred_zone);
2447
2448rebalance:
2449    /* This is the last chance, in general, before the goto nopage. */
2450    page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
2451            high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
2452            preferred_zone, migratetype);
2453    if (page)
2454        goto got_pg;
2455
2456    /* Allocate without watermarks if the context allows */
2457    if (alloc_flags & ALLOC_NO_WATERMARKS) {
2458        /*
2459         * Ignore mempolicies if ALLOC_NO_WATERMARKS on the grounds
2460         * the allocation is high priority and these type of
2461         * allocations are system rather than user orientated
2462         */
2463        zonelist = node_zonelist(numa_node_id(), gfp_mask);
2464
2465        page = __alloc_pages_high_priority(gfp_mask, order,
2466                zonelist, high_zoneidx, nodemask,
2467                preferred_zone, migratetype);
2468        if (page) {
2469            goto got_pg;
2470        }
2471    }
2472
2473    /* Atomic allocations - we can't balance anything */
2474    if (!wait)
2475        goto nopage;
2476
2477    /* Avoid recursion of direct reclaim */
2478    if (current->flags & PF_MEMALLOC)
2479        goto nopage;
2480
2481    /* Avoid allocations with no watermarks from looping endlessly */
2482    if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
2483        goto nopage;
2484
2485    /*
2486     * Try direct compaction. The first pass is asynchronous. Subsequent
2487     * attempts after direct reclaim are synchronous
2488     */
2489    page = __alloc_pages_direct_compact(gfp_mask, order,
2490                    zonelist, high_zoneidx,
2491                    nodemask,
2492                    alloc_flags, preferred_zone,
2493                    migratetype, sync_migration,
2494                    &contended_compaction,
2495                    &deferred_compaction,
2496                    &did_some_progress);
2497    if (page)
2498        goto got_pg;
2499    sync_migration = true;
2500
2501    /*
2502     * If compaction is deferred for high-order allocations, it is because
2503     * sync compaction recently failed. In this is the case and the caller
2504     * requested a movable allocation that does not heavily disrupt the
2505     * system then fail the allocation instead of entering direct reclaim.
2506     */
2507    if ((deferred_compaction || contended_compaction) &&
2508                        (gfp_mask & __GFP_NO_KSWAPD))
2509        goto nopage;
2510
2511    /* Try direct reclaim and then allocating */
2512    page = __alloc_pages_direct_reclaim(gfp_mask, order,
2513                    zonelist, high_zoneidx,
2514                    nodemask,
2515                    alloc_flags, preferred_zone,
2516                    migratetype, &did_some_progress);
2517    if (page)
2518        goto got_pg;
2519
2520    /*
2521     * If we failed to make any progress reclaiming, then we are
2522     * running out of options and have to consider going OOM
2523     */
2524    if (!did_some_progress) {
2525        if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
2526            if (oom_killer_disabled)
2527                goto nopage;
2528            /* Coredumps can quickly deplete all memory reserves */
2529            if ((current->flags & PF_DUMPCORE) &&
2530                !(gfp_mask & __GFP_NOFAIL))
2531                goto nopage;
2532            page = __alloc_pages_may_oom(gfp_mask, order,
2533                    zonelist, high_zoneidx,
2534                    nodemask, preferred_zone,
2535                    migratetype);
2536            if (page)
2537                goto got_pg;
2538
2539            if (!(gfp_mask & __GFP_NOFAIL)) {
2540                /*
2541                 * The oom killer is not called for high-order
2542                 * allocations that may fail, so if no progress
2543                 * is being made, there are no other options and
2544                 * retrying is unlikely to help.
2545                 */
2546                if (order > PAGE_ALLOC_COSTLY_ORDER)
2547                    goto nopage;
2548                /*
2549                 * The oom killer is not called for lowmem
2550                 * allocations to prevent needlessly killing
2551                 * innocent tasks.
2552                 */
2553                if (high_zoneidx < ZONE_NORMAL)
2554                    goto nopage;
2555            }
2556
2557            goto restart;
2558        }
2559    }
2560
2561    /* Check if we should retry the allocation */
2562    pages_reclaimed += did_some_progress;
2563    if (should_alloc_retry(gfp_mask, order, did_some_progress,
2564                        pages_reclaimed)) {
2565        /* Wait for some write requests to complete then retry */
2566        wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2567        goto rebalance;
2568    } else {
2569        /*
2570         * High-order allocations do not necessarily loop after
2571         * direct reclaim and reclaim/compaction depends on compaction
2572         * being called after reclaim so call directly if necessary
2573         */
2574        page = __alloc_pages_direct_compact(gfp_mask, order,
2575                    zonelist, high_zoneidx,
2576                    nodemask,
2577                    alloc_flags, preferred_zone,
2578                    migratetype, sync_migration,
2579                    &contended_compaction,
2580                    &deferred_compaction,
2581                    &did_some_progress);
2582        if (page)
2583            goto got_pg;
2584    }
2585
2586nopage:
2587    warn_alloc_failed(gfp_mask, order, NULL);
2588    return page;
2589got_pg:
2590    if (kmemcheck_enabled)
2591        kmemcheck_pagealloc_alloc(page, order, gfp_mask);
2592
2593    return page;
2594}
2595
2596/*
2597 * This is the 'heart' of the zoned buddy allocator.
2598 */
2599struct page *
2600__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
2601            struct zonelist *zonelist, nodemask_t *nodemask)
2602{
2603    enum zone_type high_zoneidx = gfp_zone(gfp_mask);
2604    struct zone *preferred_zone;
2605    struct page *page = NULL;
2606    int migratetype = allocflags_to_migratetype(gfp_mask);
2607    unsigned int cpuset_mems_cookie;
2608    int alloc_flags = ALLOC_WMARK_LOW|ALLOC_CPUSET;
2609    struct mem_cgroup *memcg = NULL;
2610
2611    gfp_mask &= gfp_allowed_mask;
2612
2613    lockdep_trace_alloc(gfp_mask);
2614
2615    might_sleep_if(gfp_mask & __GFP_WAIT);
2616
2617    if (should_fail_alloc_page(gfp_mask, order))
2618        return NULL;
2619
2620    /*
2621     * Check the zones suitable for the gfp_mask contain at least one
2622     * valid zone. It's possible to have an empty zonelist as a result
2623     * of GFP_THISNODE and a memoryless node
2624     */
2625    if (unlikely(!zonelist->_zonerefs->zone))
2626        return NULL;
2627
2628    /*
2629     * Will only have any effect when __GFP_KMEMCG is set. This is
2630     * verified in the (always inline) callee
2631     */
2632    if (!memcg_kmem_newpage_charge(gfp_mask, &memcg, order))
2633        return NULL;
2634
2635retry_cpuset:
2636    cpuset_mems_cookie = get_mems_allowed();
2637
2638    /* The preferred zone is used for statistics later */
2639    first_zones_zonelist(zonelist, high_zoneidx,
2640                nodemask ? : &cpuset_current_mems_allowed,
2641                &preferred_zone);
2642    if (!preferred_zone)
2643        goto out;
2644
2645#ifdef CONFIG_CMA
2646    if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
2647        alloc_flags |= ALLOC_CMA;
2648#endif
2649    /* First allocation attempt */
2650    page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
2651            zonelist, high_zoneidx, alloc_flags,
2652            preferred_zone, migratetype);
2653    if (unlikely(!page)) {
2654        /*
2655         * Runtime PM, block IO and its error handling path
2656         * can deadlock because I/O on the device might not
2657         * complete.
2658         */
2659        gfp_mask = memalloc_noio_flags(gfp_mask);
2660        page = __alloc_pages_slowpath(gfp_mask, order,
2661                zonelist, high_zoneidx, nodemask,
2662                preferred_zone, migratetype);
2663    }
2664
2665    trace_mm_page_alloc(page, order, gfp_mask, migratetype);
2666
2667out:
2668    /*
2669     * When updating a task's mems_allowed, it is possible to race with
2670     * parallel threads in such a way that an allocation can fail while
2671     * the mask is being updated. If a page allocation is about to fail,
2672     * check if the cpuset changed during allocation and if so, retry.
2673     */
2674    if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
2675        goto retry_cpuset;
2676
2677    memcg_kmem_commit_charge(page, memcg, order);
2678
2679    return page;
2680}
2681EXPORT_SYMBOL(__alloc_pages_nodemask);
2682
2683/*
2684 * Common helper functions.
2685 */
2686unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
2687{
2688    struct page *page;
2689
2690    /*
2691     * __get_free_pages() returns a 32-bit address, which cannot represent
2692     * a highmem page
2693     */
2694    VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
2695
2696    page = alloc_pages(gfp_mask, order);
2697    if (!page)
2698        return 0;
2699    return (unsigned long) page_address(page);
2700}
2701EXPORT_SYMBOL(__get_free_pages);
2702
2703unsigned long get_zeroed_page(gfp_t gfp_mask)
2704{
2705    return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
2706}
2707EXPORT_SYMBOL(get_zeroed_page);
2708
2709void __free_pages(struct page *page, unsigned int order)
2710{
2711    if (put_page_testzero(page)) {
2712        if (order == 0)
2713            free_hot_cold_page(page, 0);
2714        else
2715            __free_pages_ok(page, order);
2716    }
2717}
2718
2719EXPORT_SYMBOL(__free_pages);
2720
2721void free_pages(unsigned long addr, unsigned int order)
2722{
2723    if (addr != 0) {
2724        VM_BUG_ON(!virt_addr_valid((void *)addr));
2725        __free_pages(virt_to_page((void *)addr), order);
2726    }
2727}
2728
2729EXPORT_SYMBOL(free_pages);
2730
2731/*
2732 * __free_memcg_kmem_pages and free_memcg_kmem_pages will free
2733 * pages allocated with __GFP_KMEMCG.
2734 *
2735 * Those pages are accounted to a particular memcg, embedded in the
2736 * corresponding page_cgroup. To avoid adding a hit in the allocator to search
2737 * for that information only to find out that it is NULL for users who have no
2738 * interest in that whatsoever, we provide these functions.
2739 *
2740 * The caller knows better which flags it relies on.
2741 */
2742void __free_memcg_kmem_pages(struct page *page, unsigned int order)
2743{
2744    memcg_kmem_uncharge_pages(page, order);
2745    __free_pages(page, order);
2746}
2747
2748void free_memcg_kmem_pages(unsigned long addr, unsigned int order)
2749{
2750    if (addr != 0) {
2751        VM_BUG_ON(!virt_addr_valid((void *)addr));
2752        __free_memcg_kmem_pages(virt_to_page((void *)addr), order);
2753    }
2754}
2755
2756static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
2757{
2758    if (addr) {
2759        unsigned long alloc_end = addr + (PAGE_SIZE << order);
2760        unsigned long used = addr + PAGE_ALIGN(size);
2761
2762        split_page(virt_to_page((void *)addr), order);
2763        while (used < alloc_end) {
2764            free_page(used);
2765            used += PAGE_SIZE;
2766        }
2767    }
2768    return (void *)addr;
2769}
2770
2771/**
2772 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
2773 * @size: the number of bytes to allocate
2774 * @gfp_mask: GFP flags for the allocation
2775 *
2776 * This function is similar to alloc_pages(), except that it allocates the
2777 * minimum number of pages to satisfy the request. alloc_pages() can only
2778 * allocate memory in power-of-two pages.
2779 *
2780 * This function is also limited by MAX_ORDER.
2781 *
2782 * Memory allocated by this function must be released by free_pages_exact().
2783 */
2784void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
2785{
2786    unsigned int order = get_order(size);
2787    unsigned long addr;
2788
2789    addr = __get_free_pages(gfp_mask, order);
2790    return make_alloc_exact(addr, order, size);
2791}
2792EXPORT_SYMBOL(alloc_pages_exact);
2793
2794/**
2795 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
2796 * pages on a node.
2797 * @nid: the preferred node ID where memory should be allocated
2798 * @size: the number of bytes to allocate
2799 * @gfp_mask: GFP flags for the allocation
2800 *
2801 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
2802 * back.
2803 * Note this is not alloc_pages_exact_node() which allocates on a specific node,
2804 * but is not exact.
2805 */
2806void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
2807{
2808    unsigned order = get_order(size);
2809    struct page *p = alloc_pages_node(nid, gfp_mask, order);
2810    if (!p)
2811        return NULL;
2812    return make_alloc_exact((unsigned long)page_address(p), order, size);
2813}
2814EXPORT_SYMBOL(alloc_pages_exact_nid);
2815
2816/**
2817 * free_pages_exact - release memory allocated via alloc_pages_exact()
2818 * @virt: the value returned by alloc_pages_exact.
2819 * @size: size of allocation, same value as passed to alloc_pages_exact().
2820 *
2821 * Release the memory allocated by a previous call to alloc_pages_exact.
2822 */
2823void free_pages_exact(void *virt, size_t size)
2824{
2825    unsigned long addr = (unsigned long)virt;
2826    unsigned long end = addr + PAGE_ALIGN(size);
2827
2828    while (addr < end) {
2829        free_page(addr);
2830        addr += PAGE_SIZE;
2831    }
2832}
2833EXPORT_SYMBOL(free_pages_exact);
2834
2835/**
2836 * nr_free_zone_pages - count number of pages beyond high watermark
2837 * @offset: The zone index of the highest zone
2838 *
2839 * nr_free_zone_pages() counts the number of counts pages which are beyond the
2840 * high watermark within all zones at or below a given zone index. For each
2841 * zone, the number of pages is calculated as:
2842 * managed_pages - high_pages
2843 */
2844static unsigned long nr_free_zone_pages(int offset)
2845{
2846    struct zoneref *z;
2847    struct zone *zone;
2848
2849    /* Just pick one node, since fallback list is circular */
2850    unsigned long sum = 0;
2851
2852    struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
2853
2854    for_each_zone_zonelist(zone, z, zonelist, offset) {
2855        unsigned long size = zone->managed_pages;
2856        unsigned long high = high_wmark_pages(zone);
2857        if (size > high)
2858            sum += size - high;
2859    }
2860
2861    return sum;
2862}
2863
2864/**
2865 * nr_free_buffer_pages - count number of pages beyond high watermark
2866 *
2867 * nr_free_buffer_pages() counts the number of pages which are beyond the high
2868 * watermark within ZONE_DMA and ZONE_NORMAL.
2869 */
2870unsigned long nr_free_buffer_pages(void)
2871{
2872    return nr_free_zone_pages(gfp_zone(GFP_USER));
2873}
2874EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
2875
2876/**
2877 * nr_free_pagecache_pages - count number of pages beyond high watermark
2878 *
2879 * nr_free_pagecache_pages() counts the number of pages which are beyond the
2880 * high watermark within all zones.
2881 */
2882unsigned long nr_free_pagecache_pages(void)
2883{
2884    return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
2885}
2886
2887static inline void show_node(struct zone *zone)
2888{
2889    if (IS_ENABLED(CONFIG_NUMA))
2890        printk("Node %d ", zone_to_nid(zone));
2891}
2892
2893void si_meminfo(struct sysinfo *val)
2894{
2895    val->totalram = totalram_pages;
2896    val->sharedram = 0;
2897    val->freeram = global_page_state(NR_FREE_PAGES);
2898    val->bufferram = nr_blockdev_pages();
2899    val->totalhigh = totalhigh_pages;
2900    val->freehigh = nr_free_highpages();
2901    val->mem_unit = PAGE_SIZE;
2902}
2903
2904EXPORT_SYMBOL(si_meminfo);
2905
2906#ifdef CONFIG_NUMA
2907void si_meminfo_node(struct sysinfo *val, int nid)
2908{
2909    int zone_type; /* needs to be signed */
2910    unsigned long managed_pages = 0;
2911    pg_data_t *pgdat = NODE_DATA(nid);
2912
2913    for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
2914        managed_pages += pgdat->node_zones[zone_type].managed_pages;
2915    val->totalram = managed_pages;
2916    val->freeram = node_page_state(nid, NR_FREE_PAGES);
2917#ifdef CONFIG_HIGHMEM
2918    val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].managed_pages;
2919    val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
2920            NR_FREE_PAGES);
2921#else
2922    val->totalhigh = 0;
2923    val->freehigh = 0;
2924#endif
2925    val->mem_unit = PAGE_SIZE;
2926}
2927#endif
2928
2929/*
2930 * Determine whether the node should be displayed or not, depending on whether
2931 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
2932 */
2933bool skip_free_areas_node(unsigned int flags, int nid)
2934{
2935    bool ret = false;
2936    unsigned int cpuset_mems_cookie;
2937
2938    if (!(flags & SHOW_MEM_FILTER_NODES))
2939        goto out;
2940
2941    do {
2942        cpuset_mems_cookie = get_mems_allowed();
2943        ret = !node_isset(nid, cpuset_current_mems_allowed);
2944    } while (!put_mems_allowed(cpuset_mems_cookie));
2945out:
2946    return ret;
2947}
2948
2949#define K(x) ((x) << (PAGE_SHIFT-10))
2950
2951static void show_migration_types(unsigned char type)
2952{
2953    static const char types[MIGRATE_TYPES] = {
2954        [MIGRATE_UNMOVABLE] = 'U',
2955        [MIGRATE_RECLAIMABLE] = 'E',
2956        [MIGRATE_MOVABLE] = 'M',
2957        [MIGRATE_RESERVE] = 'R',
2958#ifdef CONFIG_CMA
2959        [MIGRATE_CMA] = 'C',
2960#endif
2961#ifdef CONFIG_MEMORY_ISOLATION
2962        [MIGRATE_ISOLATE] = 'I',
2963#endif
2964    };
2965    char tmp[MIGRATE_TYPES + 1];
2966    char *p = tmp;
2967    int i;
2968
2969    for (i = 0; i < MIGRATE_TYPES; i++) {
2970        if (type & (1 << i))
2971            *p++ = types[i];
2972    }
2973
2974    *p = '\0';
2975    printk("(%s) ", tmp);
2976}
2977
2978/*
2979 * Show free area list (used inside shift_scroll-lock stuff)
2980 * We also calculate the percentage fragmentation. We do this by counting the
2981 * memory on each free list with the exception of the first item on the list.
2982 * Suppresses nodes that are not allowed by current's cpuset if
2983 * SHOW_MEM_FILTER_NODES is passed.
2984 */
2985void show_free_areas(unsigned int filter)
2986{
2987    int cpu;
2988    struct zone *zone;
2989
2990    for_each_populated_zone(zone) {
2991        if (skip_free_areas_node(filter, zone_to_nid(zone)))
2992            continue;
2993        show_node(zone);
2994        printk("%s per-cpu:\n", zone->name);
2995
2996        for_each_online_cpu(cpu) {
2997            struct per_cpu_pageset *pageset;
2998
2999            pageset = per_cpu_ptr(zone->pageset, cpu);
3000
3001            printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
3002                   cpu, pageset->pcp.high,
3003                   pageset->pcp.batch, pageset->pcp.count);
3004        }
3005    }
3006
3007    printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
3008        " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
3009        " unevictable:%lu"
3010        " dirty:%lu writeback:%lu unstable:%lu\n"
3011        " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
3012        " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
3013        " free_cma:%lu\n",
3014        global_page_state(NR_ACTIVE_ANON),
3015        global_page_state(NR_INACTIVE_ANON),
3016        global_page_state(NR_ISOLATED_ANON),
3017        global_page_state(NR_ACTIVE_FILE),
3018        global_page_state(NR_INACTIVE_FILE),
3019        global_page_state(NR_ISOLATED_FILE),
3020        global_page_state(NR_UNEVICTABLE),
3021        global_page_state(NR_FILE_DIRTY),
3022        global_page_state(NR_WRITEBACK),
3023        global_page_state(NR_UNSTABLE_NFS),
3024        global_page_state(NR_FREE_PAGES),
3025        global_page_state(NR_SLAB_RECLAIMABLE),
3026        global_page_state(NR_SLAB_UNRECLAIMABLE),
3027        global_page_state(NR_FILE_MAPPED),
3028        global_page_state(NR_SHMEM),
3029        global_page_state(NR_PAGETABLE),
3030        global_page_state(NR_BOUNCE),
3031        global_page_state(NR_FREE_CMA_PAGES));
3032
3033    for_each_populated_zone(zone) {
3034        int i;
3035
3036        if (skip_free_areas_node(filter, zone_to_nid(zone)))
3037            continue;
3038        show_node(zone);
3039        printk("%s"
3040            " free:%lukB"
3041            " min:%lukB"
3042            " low:%lukB"
3043            " high:%lukB"
3044            " active_anon:%lukB"
3045            " inactive_anon:%lukB"
3046            " active_file:%lukB"
3047            " inactive_file:%lukB"
3048            " unevictable:%lukB"
3049            " isolated(anon):%lukB"
3050            " isolated(file):%lukB"
3051            " present:%lukB"
3052            " managed:%lukB"
3053            " mlocked:%lukB"
3054            " dirty:%lukB"
3055            " writeback:%lukB"
3056            " mapped:%lukB"
3057            " shmem:%lukB"
3058            " slab_reclaimable:%lukB"
3059            " slab_unreclaimable:%lukB"
3060            " kernel_stack:%lukB"
3061            " pagetables:%lukB"
3062            " unstable:%lukB"
3063            " bounce:%lukB"
3064            " free_cma:%lukB"
3065            " writeback_tmp:%lukB"
3066            " pages_scanned:%lu"
3067            " all_unreclaimable? %s"
3068            "\n",
3069            zone->name,
3070            K(zone_page_state(zone, NR_FREE_PAGES)),
3071            K(min_wmark_pages(zone)),
3072            K(low_wmark_pages(zone)),
3073            K(high_wmark_pages(zone)),
3074            K(zone_page_state(zone, NR_ACTIVE_ANON)),
3075            K(zone_page_state(zone, NR_INACTIVE_ANON)),
3076            K(zone_page_state(zone, NR_ACTIVE_FILE)),
3077            K(zone_page_state(zone, NR_INACTIVE_FILE)),
3078            K(zone_page_state(zone, NR_UNEVICTABLE)),
3079            K(zone_page_state(zone, NR_ISOLATED_ANON)),
3080            K(zone_page_state(zone, NR_ISOLATED_FILE)),
3081            K(zone->present_pages),
3082            K(zone->managed_pages),
3083            K(zone_page_state(zone, NR_MLOCK)),
3084            K(zone_page_state(zone, NR_FILE_DIRTY)),
3085            K(zone_page_state(zone, NR_WRITEBACK)),
3086            K(zone_page_state(zone, NR_FILE_MAPPED)),
3087            K(zone_page_state(zone, NR_SHMEM)),
3088            K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
3089            K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
3090            zone_page_state(zone, NR_KERNEL_STACK) *
3091                THREAD_SIZE / 1024,
3092            K(zone_page_state(zone, NR_PAGETABLE)),
3093            K(zone_page_state(zone, NR_UNSTABLE_NFS)),
3094            K(zone_page_state(zone, NR_BOUNCE)),
3095            K(zone_page_state(zone, NR_FREE_CMA_PAGES)),
3096            K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
3097            zone->pages_scanned,
3098            (zone->all_unreclaimable ? "yes" : "no")
3099            );
3100        printk("lowmem_reserve[]:");
3101        for (i = 0; i < MAX_NR_ZONES; i++)
3102            printk(" %lu", zone->lowmem_reserve[i]);
3103        printk("\n");
3104    }
3105
3106    for_each_populated_zone(zone) {
3107         unsigned long nr[MAX_ORDER], flags, order, total = 0;
3108        unsigned char types[MAX_ORDER];
3109
3110        if (skip_free_areas_node(filter, zone_to_nid(zone)))
3111            continue;
3112        show_node(zone);
3113        printk("%s: ", zone->name);
3114
3115        spin_lock_irqsave(&zone->lock, flags);
3116        for (order = 0; order < MAX_ORDER; order++) {
3117            struct free_area *area = &zone->free_area[order];
3118            int type;
3119
3120            nr[order] = area->nr_free;
3121            total += nr[order] << order;
3122
3123            types[order] = 0;
3124            for (type = 0; type < MIGRATE_TYPES; type++) {
3125                if (!list_empty(&area->free_list[type]))
3126                    types[order] |= 1 << type;
3127            }
3128        }
3129        spin_unlock_irqrestore(&zone->lock, flags);
3130        for (order = 0; order < MAX_ORDER; order++) {
3131            printk("%lu*%lukB ", nr[order], K(1UL) << order);
3132            if (nr[order])
3133                show_migration_types(types[order]);
3134        }
3135        printk("= %lukB\n", K(total));
3136    }
3137
3138    hugetlb_show_meminfo();
3139
3140    printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
3141
3142    show_swap_cache_info();
3143}
3144
3145static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
3146{
3147    zoneref->zone = zone;
3148    zoneref->zone_idx = zone_idx(zone);
3149}
3150
3151/*
3152 * Builds allocation fallback zone lists.
3153 *
3154 * Add all populated zones of a node to the zonelist.
3155 */
3156static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
3157                int nr_zones)
3158{
3159    struct zone *zone;
3160    enum zone_type zone_type = MAX_NR_ZONES;
3161
3162    do {
3163        zone_type--;
3164        zone = pgdat->node_zones + zone_type;
3165        if (populated_zone(zone)) {
3166            zoneref_set_zone(zone,
3167                &zonelist->_zonerefs[nr_zones++]);
3168            check_highest_zone(zone_type);
3169        }
3170    } while (zone_type);
3171
3172    return nr_zones;
3173}
3174
3175
3176/*
3177 * zonelist_order:
3178 * 0 = automatic detection of better ordering.
3179 * 1 = order by ([node] distance, -zonetype)
3180 * 2 = order by (-zonetype, [node] distance)
3181 *
3182 * If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
3183 * the same zonelist. So only NUMA can configure this param.
3184 */
3185#define ZONELIST_ORDER_DEFAULT 0
3186#define ZONELIST_ORDER_NODE 1
3187#define ZONELIST_ORDER_ZONE 2
3188
3189/* zonelist order in the kernel.
3190 * set_zonelist_order() will set this to NODE or ZONE.
3191 */
3192static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
3193static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
3194
3195
3196#ifdef CONFIG_NUMA
3197/* The value user specified ....changed by config */
3198static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
3199/* string for sysctl */
3200#define NUMA_ZONELIST_ORDER_LEN 16
3201char numa_zonelist_order[16] = "default";
3202
3203/*
3204 * interface for configure zonelist ordering.
3205 * command line option "numa_zonelist_order"
3206 * = "[dD]efault - default, automatic configuration.
3207 * = "[nN]ode - order by node locality, then by zone within node
3208 * = "[zZ]one - order by zone, then by locality within zone
3209 */
3210
3211static int __parse_numa_zonelist_order(char *s)
3212{
3213    if (*s == 'd' || *s == 'D') {
3214        user_zonelist_order = ZONELIST_ORDER_DEFAULT;
3215    } else if (*s == 'n' || *s == 'N') {
3216        user_zonelist_order = ZONELIST_ORDER_NODE;
3217    } else if (*s == 'z' || *s == 'Z') {
3218        user_zonelist_order = ZONELIST_ORDER_ZONE;
3219    } else {
3220        printk(KERN_WARNING
3221            "Ignoring invalid numa_zonelist_order value: "
3222            "%s\n", s);
3223        return -EINVAL;
3224    }
3225    return 0;
3226}
3227
3228static __init int setup_numa_zonelist_order(char *s)
3229{
3230    int ret;
3231
3232    if (!s)
3233        return 0;
3234
3235    ret = __parse_numa_zonelist_order(s);
3236    if (ret == 0)
3237        strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
3238
3239    return ret;
3240}
3241early_param("numa_zonelist_order", setup_numa_zonelist_order);
3242
3243/*
3244 * sysctl handler for numa_zonelist_order
3245 */
3246int numa_zonelist_order_handler(ctl_table *table, int write,
3247        void __user *buffer, size_t *length,
3248        loff_t *ppos)
3249{
3250    char saved_string[NUMA_ZONELIST_ORDER_LEN];
3251    int ret;
3252    static DEFINE_MUTEX(zl_order_mutex);
3253
3254    mutex_lock(&zl_order_mutex);
3255    if (write) {
3256        if (strlen((char *)table->data) >= NUMA_ZONELIST_ORDER_LEN) {
3257            ret = -EINVAL;
3258            goto out;
3259        }
3260        strcpy(saved_string, (char *)table->data);
3261    }
3262    ret = proc_dostring(table, write, buffer, length, ppos);
3263    if (ret)
3264        goto out;
3265    if (write) {
3266        int oldval = user_zonelist_order;
3267
3268        ret = __parse_numa_zonelist_order((char *)table->data);
3269        if (ret) {
3270            /*
3271             * bogus value. restore saved string
3272             */
3273            strncpy((char *)table->data, saved_string,
3274                NUMA_ZONELIST_ORDER_LEN);
3275            user_zonelist_order = oldval;
3276        } else if (oldval != user_zonelist_order) {
3277            mutex_lock(&zonelists_mutex);
3278            build_all_zonelists(NULL, NULL);
3279            mutex_unlock(&zonelists_mutex);
3280        }
3281    }
3282out:
3283    mutex_unlock(&zl_order_mutex);
3284    return ret;
3285}
3286
3287
3288#define MAX_NODE_LOAD (nr_online_nodes)
3289static int node_load[MAX_NUMNODES];
3290
3291/**
3292 * find_next_best_node - find the next node that should appear in a given node's fallback list
3293 * @node: node whose fallback list we're appending
3294 * @used_node_mask: nodemask_t of already used nodes
3295 *
3296 * We use a number of factors to determine which is the next node that should
3297 * appear on a given node's fallback list. The node should not have appeared
3298 * already in @node's fallback list, and it should be the next closest node
3299 * according to the distance array (which contains arbitrary distance values
3300 * from each node to each node in the system), and should also prefer nodes
3301 * with no CPUs, since presumably they'll have very little allocation pressure
3302 * on them otherwise.
3303 * It returns -1 if no node is found.
3304 */
3305static int find_next_best_node(int node, nodemask_t *used_node_mask)
3306{
3307    int n, val;
3308    int min_val = INT_MAX;
3309    int best_node = NUMA_NO_NODE;
3310    const struct cpumask *tmp = cpumask_of_node(0);
3311
3312    /* Use the local node if we haven't already */
3313    if (!node_isset(node, *used_node_mask)) {
3314        node_set(node, *used_node_mask);
3315        return node;
3316    }
3317
3318    for_each_node_state(n, N_MEMORY) {
3319
3320        /* Don't want a node to appear more than once */
3321        if (node_isset(n, *used_node_mask))
3322            continue;
3323
3324        /* Use the distance array to find the distance */
3325        val = node_distance(node, n);
3326
3327        /* Penalize nodes under us ("prefer the next node") */
3328        val += (n < node);
3329
3330        /* Give preference to headless and unused nodes */
3331        tmp = cpumask_of_node(n);
3332        if (!cpumask_empty(tmp))
3333            val += PENALTY_FOR_NODE_WITH_CPUS;
3334
3335        /* Slight preference for less loaded node */
3336        val *= (MAX_NODE_LOAD*MAX_NUMNODES);
3337        val += node_load[n];
3338
3339        if (val < min_val) {
3340            min_val = val;
3341            best_node = n;
3342        }
3343    }
3344
3345    if (best_node >= 0)
3346        node_set(best_node, *used_node_mask);
3347
3348    return best_node;
3349}
3350
3351
3352/*
3353 * Build zonelists ordered by node and zones within node.
3354 * This results in maximum locality--normal zone overflows into local
3355 * DMA zone, if any--but risks exhausting DMA zone.
3356 */
3357static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
3358{
3359    int j;
3360    struct zonelist *zonelist;
3361
3362    zonelist = &pgdat->node_zonelists[0];
3363    for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
3364        ;
3365    j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3366    zonelist->_zonerefs[j].zone = NULL;
3367    zonelist->_zonerefs[j].zone_idx = 0;
3368}
3369
3370/*
3371 * Build gfp_thisnode zonelists
3372 */
3373static void build_thisnode_zonelists(pg_data_t *pgdat)
3374{
3375    int j;
3376    struct zonelist *zonelist;
3377
3378    zonelist = &pgdat->node_zonelists[1];
3379    j = build_zonelists_node(pgdat, zonelist, 0);
3380    zonelist->_zonerefs[j].zone = NULL;
3381    zonelist->_zonerefs[j].zone_idx = 0;
3382}
3383
3384/*
3385 * Build zonelists ordered by zone and nodes within zones.
3386 * This results in conserving DMA zone[s] until all Normal memory is
3387 * exhausted, but results in overflowing to remote node while memory
3388 * may still exist in local DMA zone.
3389 */
3390static int node_order[MAX_NUMNODES];
3391
3392static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
3393{
3394    int pos, j, node;
3395    int zone_type; /* needs to be signed */
3396    struct zone *z;
3397    struct zonelist *zonelist;
3398
3399    zonelist = &pgdat->node_zonelists[0];
3400    pos = 0;
3401    for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
3402        for (j = 0; j < nr_nodes; j++) {
3403            node = node_order[j];
3404            z = &NODE_DATA(node)->node_zones[zone_type];
3405            if (populated_zone(z)) {
3406                zoneref_set_zone(z,
3407                    &zonelist->_zonerefs[pos++]);
3408                check_highest_zone(zone_type);
3409            }
3410        }
3411    }
3412    zonelist->_zonerefs[pos].zone = NULL;
3413    zonelist->_zonerefs[pos].zone_idx = 0;
3414}
3415
3416static int default_zonelist_order(void)
3417{
3418    int nid, zone_type;
3419    unsigned long low_kmem_size,total_size;
3420    struct zone *z;
3421    int average_size;
3422    /*
3423         * ZONE_DMA and ZONE_DMA32 can be very small area in the system.
3424     * If they are really small and used heavily, the system can fall
3425     * into OOM very easily.
3426     * This function detect ZONE_DMA/DMA32 size and configures zone order.
3427     */
3428    /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
3429    low_kmem_size = 0;
3430    total_size = 0;
3431    for_each_online_node(nid) {
3432        for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3433            z = &NODE_DATA(nid)->node_zones[zone_type];
3434            if (populated_zone(z)) {
3435                if (zone_type < ZONE_NORMAL)
3436                    low_kmem_size += z->managed_pages;
3437                total_size += z->managed_pages;
3438            } else if (zone_type == ZONE_NORMAL) {
3439                /*
3440                 * If any node has only lowmem, then node order
3441                 * is preferred to allow kernel allocations
3442                 * locally; otherwise, they can easily infringe
3443                 * on other nodes when there is an abundance of
3444                 * lowmem available to allocate from.
3445                 */
3446                return ZONELIST_ORDER_NODE;
3447            }
3448        }
3449    }
3450    if (!low_kmem_size || /* there are no DMA area. */
3451        low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
3452        return ZONELIST_ORDER_NODE;
3453    /*
3454     * look into each node's config.
3455       * If there is a node whose DMA/DMA32 memory is very big area on
3456      * local memory, NODE_ORDER may be suitable.
3457         */
3458    average_size = total_size /
3459                (nodes_weight(node_states[N_MEMORY]) + 1);
3460    for_each_online_node(nid) {
3461        low_kmem_size = 0;
3462        total_size = 0;
3463        for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3464            z = &NODE_DATA(nid)->node_zones[zone_type];
3465            if (populated_zone(z)) {
3466                if (zone_type < ZONE_NORMAL)
3467                    low_kmem_size += z->present_pages;
3468                total_size += z->present_pages;
3469            }
3470        }
3471        if (low_kmem_size &&
3472            total_size > average_size && /* ignore small node */
3473            low_kmem_size > total_size * 70/100)
3474            return ZONELIST_ORDER_NODE;
3475    }
3476    return ZONELIST_ORDER_ZONE;
3477}
3478
3479static void set_zonelist_order(void)
3480{
3481    if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
3482        current_zonelist_order = default_zonelist_order();
3483    else
3484        current_zonelist_order = user_zonelist_order;
3485}
3486
3487static void build_zonelists(pg_data_t *pgdat)
3488{
3489    int j, node, load;
3490    enum zone_type i;
3491    nodemask_t used_mask;
3492    int local_node, prev_node;
3493    struct zonelist *zonelist;
3494    int order = current_zonelist_order;
3495
3496    /* initialize zonelists */
3497    for (i = 0; i < MAX_ZONELISTS; i++) {
3498        zonelist = pgdat->node_zonelists + i;
3499        zonelist->_zonerefs[0].zone = NULL;
3500        zonelist->_zonerefs[0].zone_idx = 0;
3501    }
3502
3503    /* NUMA-aware ordering of nodes */
3504    local_node = pgdat->node_id;
3505    load = nr_online_nodes;
3506    prev_node = local_node;
3507    nodes_clear(used_mask);
3508
3509    memset(node_order, 0, sizeof(node_order));
3510    j = 0;
3511
3512    while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
3513        /*
3514         * We don't want to pressure a particular node.
3515         * So adding penalty to the first node in same
3516         * distance group to make it round-robin.
3517         */
3518        if (node_distance(local_node, node) !=
3519            node_distance(local_node, prev_node))
3520            node_load[node] = load;
3521
3522        prev_node = node;
3523        load--;
3524        if (order == ZONELIST_ORDER_NODE)
3525            build_zonelists_in_node_order(pgdat, node);
3526        else
3527            node_order[j++] = node; /* remember order */
3528    }
3529
3530    if (order == ZONELIST_ORDER_ZONE) {
3531        /* calculate node order -- i.e., DMA last! */
3532        build_zonelists_in_zone_order(pgdat, j);
3533    }
3534
3535    build_thisnode_zonelists(pgdat);
3536}
3537
3538/* Construct the zonelist performance cache - see further mmzone.h */
3539static void build_zonelist_cache(pg_data_t *pgdat)
3540{
3541    struct zonelist *zonelist;
3542    struct zonelist_cache *zlc;
3543    struct zoneref *z;
3544
3545    zonelist = &pgdat->node_zonelists[0];
3546    zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
3547    bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
3548    for (z = zonelist->_zonerefs; z->zone; z++)
3549        zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
3550}
3551
3552#ifdef CONFIG_HAVE_MEMORYLESS_NODES
3553/*
3554 * Return node id of node used for "local" allocations.
3555 * I.e., first node id of first zone in arg node's generic zonelist.
3556 * Used for initializing percpu 'numa_mem', which is used primarily
3557 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
3558 */
3559int local_memory_node(int node)
3560{
3561    struct zone *zone;
3562
3563    (void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
3564                   gfp_zone(GFP_KERNEL),
3565                   NULL,
3566                   &zone);
3567    return zone->node;
3568}
3569#endif
3570
3571#else /* CONFIG_NUMA */
3572
3573static void set_zonelist_order(void)
3574{
3575    current_zonelist_order = ZONELIST_ORDER_ZONE;
3576}
3577
3578static void build_zonelists(pg_data_t *pgdat)
3579{
3580    int node, local_node;
3581    enum zone_type j;
3582    struct zonelist *zonelist;
3583
3584    local_node = pgdat->node_id;
3585
3586    zonelist = &pgdat->node_zonelists[0];
3587    j = build_zonelists_node(pgdat, zonelist, 0);
3588
3589    /*
3590     * Now we build the zonelist so that it contains the zones
3591     * of all the other nodes.
3592     * We don't want to pressure a particular node, so when
3593     * building the zones for node N, we make sure that the
3594     * zones coming right after the local ones are those from
3595     * node N+1 (modulo N)
3596     */
3597    for (node = local_node + 1; node < MAX_NUMNODES; node++) {
3598        if (!node_online(node))
3599            continue;
3600        j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3601    }
3602    for (node = 0; node < local_node; node++) {
3603        if (!node_online(node))
3604            continue;
3605        j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3606    }
3607
3608    zonelist->_zonerefs[j].zone = NULL;
3609    zonelist->_zonerefs[j].zone_idx = 0;
3610}
3611
3612/* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
3613static void build_zonelist_cache(pg_data_t *pgdat)
3614{
3615    pgdat->node_zonelists[0].zlcache_ptr = NULL;
3616}
3617
3618#endif /* CONFIG_NUMA */
3619
3620/*
3621 * Boot pageset table. One per cpu which is going to be used for all
3622 * zones and all nodes. The parameters will be set in such a way
3623 * that an item put on a list will immediately be handed over to
3624 * the buddy list. This is safe since pageset manipulation is done
3625 * with interrupts disabled.
3626 *
3627 * The boot_pagesets must be kept even after bootup is complete for
3628 * unused processors and/or zones. They do play a role for bootstrapping
3629 * hotplugged processors.
3630 *
3631 * zoneinfo_show() and maybe other functions do
3632 * not check if the processor is online before following the pageset pointer.
3633 * Other parts of the kernel may not check if the zone is available.
3634 */
3635static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
3636static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
3637static void setup_zone_pageset(struct zone *zone);
3638
3639/*
3640 * Global mutex to protect against size modification of zonelists
3641 * as well as to serialize pageset setup for the new populated zone.
3642 */
3643DEFINE_MUTEX(zonelists_mutex);
3644
3645/* return values int ....just for stop_machine() */
3646static int __build_all_zonelists(void *data)
3647{
3648    int nid;
3649    int cpu;
3650    pg_data_t *self = data;
3651
3652#ifdef CONFIG_NUMA
3653    memset(node_load, 0, sizeof(node_load));
3654#endif
3655
3656    if (self && !node_online(self->node_id)) {
3657        build_zonelists(self);
3658        build_zonelist_cache(self);
3659    }
3660
3661    for_each_online_node(nid) {
3662        pg_data_t *pgdat = NODE_DATA(nid);
3663
3664        build_zonelists(pgdat);
3665        build_zonelist_cache(pgdat);
3666    }
3667
3668    /*
3669     * Initialize the boot_pagesets that are going to be used
3670     * for bootstrapping processors. The real pagesets for
3671     * each zone will be allocated later when the per cpu
3672     * allocator is available.
3673     *
3674     * boot_pagesets are used also for bootstrapping offline
3675     * cpus if the system is already booted because the pagesets
3676     * are needed to initialize allocators on a specific cpu too.
3677     * F.e. the percpu allocator needs the page allocator which
3678     * needs the percpu allocator in order to allocate its pagesets
3679     * (a chicken-egg dilemma).
3680     */
3681    for_each_possible_cpu(cpu) {
3682        setup_pageset(&per_cpu(boot_pageset, cpu), 0);
3683
3684#ifdef CONFIG_HAVE_MEMORYLESS_NODES
3685        /*
3686         * We now know the "local memory node" for each node--
3687         * i.e., the node of the first zone in the generic zonelist.
3688         * Set up numa_mem percpu variable for on-line cpus. During
3689         * boot, only the boot cpu should be on-line; we'll init the
3690         * secondary cpus' numa_mem as they come on-line. During
3691         * node/memory hotplug, we'll fixup all on-line cpus.
3692         */
3693        if (cpu_online(cpu))
3694            set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
3695#endif
3696    }
3697
3698    return 0;
3699}
3700
3701/*
3702 * Called with zonelists_mutex held always
3703 * unless system_state == SYSTEM_BOOTING.
3704 */
3705void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone)
3706{
3707    set_zonelist_order();
3708
3709    if (system_state == SYSTEM_BOOTING) {
3710        __build_all_zonelists(NULL);
3711        mminit_verify_zonelist();
3712        cpuset_init_current_mems_allowed();
3713    } else {
3714#ifdef CONFIG_MEMORY_HOTPLUG
3715        if (zone)
3716            setup_zone_pageset(zone);
3717#endif
3718        /* we have to stop all cpus to guarantee there is no user
3719           of zonelist */
3720        stop_machine(__build_all_zonelists, pgdat, NULL);
3721        /* cpuset refresh routine should be here */
3722    }
3723    vm_total_pages = nr_free_pagecache_pages();
3724    /*
3725     * Disable grouping by mobility if the number of pages in the
3726     * system is too low to allow the mechanism to work. It would be
3727     * more accurate, but expensive to check per-zone. This check is
3728     * made on memory-hotadd so a system can start with mobility
3729     * disabled and enable it later
3730     */
3731    if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
3732        page_group_by_mobility_disabled = 1;
3733    else
3734        page_group_by_mobility_disabled = 0;
3735
3736    printk("Built %i zonelists in %s order, mobility grouping %s. "
3737        "Total pages: %ld\n",
3738            nr_online_nodes,
3739            zonelist_order_name[current_zonelist_order],
3740            page_group_by_mobility_disabled ? "off" : "on",
3741            vm_total_pages);
3742#ifdef CONFIG_NUMA
3743    printk("Policy zone: %s\n", zone_names[policy_zone]);
3744#endif
3745}
3746
3747/*
3748 * Helper functions to size the waitqueue hash table.
3749 * Essentially these want to choose hash table sizes sufficiently
3750 * large so that collisions trying to wait on pages are rare.
3751 * But in fact, the number of active page waitqueues on typical
3752 * systems is ridiculously low, less than 200. So this is even
3753 * conservative, even though it seems large.
3754 *
3755 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
3756 * waitqueues, i.e. the size of the waitq table given the number of pages.
3757 */
3758#define PAGES_PER_WAITQUEUE 256
3759
3760#ifndef CONFIG_MEMORY_HOTPLUG
3761static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3762{
3763    unsigned long size = 1;
3764
3765    pages /= PAGES_PER_WAITQUEUE;
3766
3767    while (size < pages)
3768        size <<= 1;
3769
3770    /*
3771     * Once we have dozens or even hundreds of threads sleeping
3772     * on IO we've got bigger problems than wait queue collision.
3773     * Limit the size of the wait table to a reasonable size.
3774     */
3775    size = min(size, 4096UL);
3776
3777    return max(size, 4UL);
3778}
3779#else
3780/*
3781 * A zone's size might be changed by hot-add, so it is not possible to determine
3782 * a suitable size for its wait_table. So we use the maximum size now.
3783 *
3784 * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie:
3785 *
3786 * i386 (preemption config) : 4096 x 16 = 64Kbyte.
3787 * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
3788 * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte.
3789 *
3790 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
3791 * or more by the traditional way. (See above). It equals:
3792 *
3793 * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte.
3794 * ia64(16K page size) : = ( 8G + 4M)byte.
3795 * powerpc (64K page size) : = (32G +16M)byte.
3796 */
3797static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3798{
3799    return 4096UL;
3800}
3801#endif
3802
3803/*
3804 * This is an integer logarithm so that shifts can be used later
3805 * to extract the more random high bits from the multiplicative
3806 * hash function before the remainder is taken.
3807 */
3808static inline unsigned long wait_table_bits(unsigned long size)
3809{
3810    return ffz(~size);
3811}
3812
3813#define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
3814
3815/*
3816 * Check if a pageblock contains reserved pages
3817 */
3818static int pageblock_is_reserved(unsigned long start_pfn, unsigned long end_pfn)
3819{
3820    unsigned long pfn;
3821
3822    for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3823        if (!pfn_valid_within(pfn) || PageReserved(pfn_to_page(pfn)))
3824            return 1;
3825    }
3826    return 0;
3827}
3828
3829/*
3830 * Mark a number of pageblocks as MIGRATE_RESERVE. The number
3831 * of blocks reserved is based on min_wmark_pages(zone). The memory within
3832 * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
3833 * higher will lead to a bigger reserve which will get freed as contiguous
3834 * blocks as reclaim kicks in
3835 */
3836static void setup_zone_migrate_reserve(struct zone *zone)
3837{
3838    unsigned long start_pfn, pfn, end_pfn, block_end_pfn;
3839    struct page *page;
3840    unsigned long block_migratetype;
3841    int reserve;
3842
3843    /*
3844     * Get the start pfn, end pfn and the number of blocks to reserve
3845     * We have to be careful to be aligned to pageblock_nr_pages to
3846     * make sure that we always check pfn_valid for the first page in
3847     * the block.
3848     */
3849    start_pfn = zone->zone_start_pfn;
3850    end_pfn = zone_end_pfn(zone);
3851    start_pfn = roundup(start_pfn, pageblock_nr_pages);
3852    reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
3853                            pageblock_order;
3854
3855    /*
3856     * Reserve blocks are generally in place to help high-order atomic
3857     * allocations that are short-lived. A min_free_kbytes value that
3858     * would result in more than 2 reserve blocks for atomic allocations
3859     * is assumed to be in place to help anti-fragmentation for the
3860     * future allocation of hugepages at runtime.
3861     */
3862    reserve = min(2, reserve);
3863
3864    for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
3865        if (!pfn_valid(pfn))
3866            continue;
3867        page = pfn_to_page(pfn);
3868
3869        /* Watch out for overlapping nodes */
3870        if (page_to_nid(page) != zone_to_nid(zone))
3871            continue;
3872
3873        block_migratetype = get_pageblock_migratetype(page);
3874
3875        /* Only test what is necessary when the reserves are not met */
3876        if (reserve > 0) {
3877            /*
3878             * Blocks with reserved pages will never free, skip
3879             * them.
3880             */
3881            block_end_pfn = min(pfn + pageblock_nr_pages, end_pfn);
3882            if (pageblock_is_reserved(pfn, block_end_pfn))
3883                continue;
3884
3885            /* If this block is reserved, account for it */
3886            if (block_migratetype == MIGRATE_RESERVE) {
3887                reserve--;
3888                continue;
3889            }
3890
3891            /* Suitable for reserving if this block is movable */
3892            if (block_migratetype == MIGRATE_MOVABLE) {
3893                set_pageblock_migratetype(page,
3894                            MIGRATE_RESERVE);
3895                move_freepages_block(zone, page,
3896                            MIGRATE_RESERVE);
3897                reserve--;
3898                continue;
3899            }
3900        }
3901
3902        /*
3903         * If the reserve is met and this is a previous reserved block,
3904         * take it back
3905         */
3906        if (block_migratetype == MIGRATE_RESERVE) {
3907            set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3908            move_freepages_block(zone, page, MIGRATE_MOVABLE);
3909        }
3910    }
3911}
3912
3913/*
3914 * Initially all pages are reserved - free ones are freed
3915 * up by free_all_bootmem() once the early boot process is
3916 * done. Non-atomic initialization, single-pass.
3917 */
3918void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
3919        unsigned long start_pfn, enum memmap_context context)
3920{
3921    struct page *page;
3922    unsigned long end_pfn = start_pfn + size;
3923    unsigned long pfn;
3924    struct zone *z;
3925
3926    if (highest_memmap_pfn < end_pfn - 1)
3927        highest_memmap_pfn = end_pfn - 1;
3928
3929    z = &NODE_DATA(nid)->node_zones[zone];
3930    for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3931        /*
3932         * There can be holes in boot-time mem_map[]s
3933         * handed to this function. They do not
3934         * exist on hotplugged memory.
3935         */
3936        if (context == MEMMAP_EARLY) {
3937            if (!early_pfn_valid(pfn))
3938                continue;
3939            if (!early_pfn_in_nid(pfn, nid))
3940                continue;
3941        }
3942        page = pfn_to_page(pfn);
3943        set_page_links(page, zone, nid, pfn);
3944        mminit_verify_page_links(page, zone, nid, pfn);
3945        init_page_count(page);
3946        page_mapcount_reset(page);
3947        page_nid_reset_last(page);
3948        SetPageReserved(page);
3949        /*
3950         * Mark the block movable so that blocks are reserved for
3951         * movable at startup. This will force kernel allocations
3952         * to reserve their blocks rather than leaking throughout
3953         * the address space during boot when many long-lived
3954         * kernel allocations are made. Later some blocks near
3955         * the start are marked MIGRATE_RESERVE by
3956         * setup_zone_migrate_reserve()
3957         *
3958         * bitmap is created for zone's valid pfn range. but memmap
3959         * can be created for invalid pages (for alignment)
3960         * check here not to call set_pageblock_migratetype() against
3961         * pfn out of zone.
3962         */
3963        if ((z->zone_start_pfn <= pfn)
3964            && (pfn < zone_end_pfn(z))
3965            && !(pfn & (pageblock_nr_pages - 1)))
3966            set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3967
3968        INIT_LIST_HEAD(&page->lru);
3969#ifdef WANT_PAGE_VIRTUAL
3970        /* The shift won't overflow because ZONE_NORMAL is below 4G. */
3971        if (!is_highmem_idx(zone))
3972            set_page_address(page, __va(pfn << PAGE_SHIFT));
3973#endif
3974    }
3975}
3976
3977static void __meminit zone_init_free_lists(struct zone *zone)
3978{
3979    int order, t;
3980    for_each_migratetype_order(order, t) {
3981        INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
3982        zone->free_area[order].nr_free = 0;
3983    }
3984}
3985
3986#ifndef __HAVE_ARCH_MEMMAP_INIT
3987#define memmap_init(size, nid, zone, start_pfn) \
3988    memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
3989#endif
3990
3991static int __meminit zone_batchsize(struct zone *zone)
3992{
3993#ifdef CONFIG_MMU
3994    int batch;
3995
3996    /*
3997     * The per-cpu-pages pools are set to around 1000th of the
3998     * size of the zone. But no more than 1/2 of a meg.
3999     *
4000     * OK, so we don't know how big the cache is. So guess.
4001     */
4002    batch = zone->managed_pages / 1024;
4003    if (batch * PAGE_SIZE > 512 * 1024)
4004        batch = (512 * 1024) / PAGE_SIZE;
4005    batch /= 4; /* We effectively *= 4 below */
4006    if (batch < 1)
4007        batch = 1;
4008
4009    /*
4010     * Clamp the batch to a 2^n - 1 value. Having a power
4011     * of 2 value was found to be more likely to have
4012     * suboptimal cache aliasing properties in some cases.
4013     *
4014     * For example if 2 tasks are alternately allocating
4015     * batches of pages, one task can end up with a lot
4016     * of pages of one half of the possible page colors
4017     * and the other with pages of the other colors.
4018     */
4019    batch = rounddown_pow_of_two(batch + batch/2) - 1;
4020
4021    return batch;
4022
4023#else
4024    /* The deferral and batching of frees should be suppressed under NOMMU
4025     * conditions.
4026     *
4027     * The problem is that NOMMU needs to be able to allocate large chunks
4028     * of contiguous memory as there's no hardware page translation to
4029     * assemble apparent contiguous memory from discontiguous pages.
4030     *
4031     * Queueing large contiguous runs of pages for batching, however,
4032     * causes the pages to actually be freed in smaller chunks. As there
4033     * can be a significant delay between the individual batches being
4034     * recycled, this leads to the once large chunks of space being
4035     * fragmented and becoming unavailable for high-order allocations.
4036     */
4037    return 0;
4038#endif
4039}
4040
4041/*
4042 * pcp->high and pcp->batch values are related and dependent on one another:
4043 * ->batch must never be higher then ->high.
4044 * The following function updates them in a safe manner without read side
4045 * locking.
4046 *
4047 * Any new users of pcp->batch and pcp->high should ensure they can cope with
4048 * those fields changing asynchronously (acording the the above rule).
4049 *
4050 * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
4051 * outside of boot time (or some other assurance that no concurrent updaters
4052 * exist).
4053 */
4054static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
4055        unsigned long batch)
4056{
4057       /* start with a fail safe value for batch */
4058    pcp->batch = 1;
4059    smp_wmb();
4060
4061       /* Update high, then batch, in order */
4062    pcp->high = high;
4063    smp_wmb();
4064
4065    pcp->batch = batch;
4066}
4067
4068/* a companion to pageset_set_high() */
4069static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
4070{
4071    pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
4072}
4073
4074static void pageset_init(struct per_cpu_pageset *p)
4075{
4076    struct per_cpu_pages *pcp;
4077    int migratetype;
4078
4079    memset(p, 0, sizeof(*p));
4080
4081    pcp = &p->pcp;
4082    pcp->count = 0;
4083    for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
4084        INIT_LIST_HEAD(&pcp->lists[migratetype]);
4085}
4086
4087static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
4088{
4089    pageset_init(p);
4090    pageset_set_batch(p, batch);
4091}
4092
4093/*
4094 * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
4095 * to the value high for the pageset p.
4096 */
4097static void pageset_set_high(struct per_cpu_pageset *p,
4098                unsigned long high)
4099{
4100    unsigned long batch = max(1UL, high / 4);
4101    if ((high / 4) > (PAGE_SHIFT * 8))
4102        batch = PAGE_SHIFT * 8;
4103
4104    pageset_update(&p->pcp, high, batch);
4105}
4106
4107static void __meminit pageset_set_high_and_batch(struct zone *zone,
4108        struct per_cpu_pageset *pcp)
4109{
4110    if (percpu_pagelist_fraction)
4111        pageset_set_high(pcp,
4112            (zone->managed_pages /
4113                percpu_pagelist_fraction));
4114    else
4115        pageset_set_batch(pcp, zone_batchsize(zone));
4116}
4117
4118static void __meminit zone_pageset_init(struct zone *zone, int cpu)
4119{
4120    struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
4121
4122    pageset_init(pcp);
4123    pageset_set_high_and_batch(zone, pcp);
4124}
4125
4126static void __meminit setup_zone_pageset(struct zone *zone)
4127{
4128    int cpu;
4129    zone->pageset = alloc_percpu(struct per_cpu_pageset);
4130    for_each_possible_cpu(cpu)
4131        zone_pageset_init(zone, cpu);
4132}
4133
4134/*
4135 * Allocate per cpu pagesets and initialize them.
4136 * Before this call only boot pagesets were available.
4137 */
4138void __init setup_per_cpu_pageset(void)
4139{
4140    struct zone *zone;
4141
4142    for_each_populated_zone(zone)
4143        setup_zone_pageset(zone);
4144}
4145
4146static noinline __init_refok
4147int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
4148{
4149    int i;
4150    struct pglist_data *pgdat = zone->zone_pgdat;
4151    size_t alloc_size;
4152
4153    /*
4154     * The per-page waitqueue mechanism uses hashed waitqueues
4155     * per zone.
4156     */
4157    zone->wait_table_hash_nr_entries =
4158         wait_table_hash_nr_entries(zone_size_pages);
4159    zone->wait_table_bits =
4160        wait_table_bits(zone->wait_table_hash_nr_entries);
4161    alloc_size = zone->wait_table_hash_nr_entries
4162                    * sizeof(wait_queue_head_t);
4163
4164    if (!slab_is_available()) {
4165        zone->wait_table = (wait_queue_head_t *)
4166            alloc_bootmem_node_nopanic(pgdat, alloc_size);
4167    } else {
4168        /*
4169         * This case means that a zone whose size was 0 gets new memory
4170         * via memory hot-add.
4171         * But it may be the case that a new node was hot-added. In
4172         * this case vmalloc() will not be able to use this new node's
4173         * memory - this wait_table must be initialized to use this new
4174         * node itself as well.
4175         * To use this new node's memory, further consideration will be
4176         * necessary.
4177         */
4178        zone->wait_table = vmalloc(alloc_size);
4179    }
4180    if (!zone->wait_table)
4181        return -ENOMEM;
4182
4183    for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
4184        init_waitqueue_head(zone->wait_table + i);
4185
4186    return 0;
4187}
4188
4189static __meminit void zone_pcp_init(struct zone *zone)
4190{
4191    /*
4192     * per cpu subsystem is not up at this point. The following code
4193     * relies on the ability of the linker to provide the
4194     * offset of a (static) per cpu variable into the per cpu area.
4195     */
4196    zone->pageset = &boot_pageset;
4197
4198    if (zone->present_pages)
4199        printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n",
4200            zone->name, zone->present_pages,
4201                     zone_batchsize(zone));
4202}
4203
4204int __meminit init_currently_empty_zone(struct zone *zone,
4205                    unsigned long zone_start_pfn,
4206                    unsigned long size,
4207                    enum memmap_context context)
4208{
4209    struct pglist_data *pgdat = zone->zone_pgdat;
4210    int ret;
4211    ret = zone_wait_table_init(zone, size);
4212    if (ret)
4213        return ret;
4214    pgdat->nr_zones = zone_idx(zone) + 1;
4215
4216    zone->zone_start_pfn = zone_start_pfn;
4217
4218    mminit_dprintk(MMINIT_TRACE, "memmap_init",
4219            "Initialising map node %d zone %lu pfns %lu -> %lu\n",
4220            pgdat->node_id,
4221            (unsigned long)zone_idx(zone),
4222            zone_start_pfn, (zone_start_pfn + size));
4223
4224    zone_init_free_lists(zone);
4225
4226    return 0;
4227}
4228
4229#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4230#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
4231/*
4232 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
4233 * Architectures may implement their own version but if add_active_range()
4234 * was used and there are no special requirements, this is a convenient
4235 * alternative
4236 */
4237int __meminit __early_pfn_to_nid(unsigned long pfn)
4238{
4239    unsigned long start_pfn, end_pfn;
4240    int i, nid;
4241    /*
4242     * NOTE: The following SMP-unsafe globals are only used early in boot
4243     * when the kernel is running single-threaded.
4244     */
4245    static unsigned long __meminitdata last_start_pfn, last_end_pfn;
4246    static int __meminitdata last_nid;
4247
4248    if (last_start_pfn <= pfn && pfn < last_end_pfn)
4249        return last_nid;
4250
4251    for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
4252        if (start_pfn <= pfn && pfn < end_pfn) {
4253            last_start_pfn = start_pfn;
4254            last_end_pfn = end_pfn;
4255            last_nid = nid;
4256            return nid;
4257        }
4258    /* This is a memory hole */
4259    return -1;
4260}
4261#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
4262
4263int __meminit early_pfn_to_nid(unsigned long pfn)
4264{
4265    int nid;
4266
4267    nid = __early_pfn_to_nid(pfn);
4268    if (nid >= 0)
4269        return nid;
4270    /* just returns 0 */
4271    return 0;
4272}
4273
4274#ifdef CONFIG_NODES_SPAN_OTHER_NODES
4275bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
4276{
4277    int nid;
4278
4279    nid = __early_pfn_to_nid(pfn);
4280    if (nid >= 0 && nid != node)
4281        return false;
4282    return true;
4283}
4284#endif
4285
4286/**
4287 * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
4288 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
4289 * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
4290 *
4291 * If an architecture guarantees that all ranges registered with
4292 * add_active_ranges() contain no holes and may be freed, this
4293 * this function may be used instead of calling free_bootmem() manually.
4294 */
4295void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
4296{
4297    unsigned long start_pfn, end_pfn;
4298    int i, this_nid;
4299
4300    for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
4301        start_pfn = min(start_pfn, max_low_pfn);
4302        end_pfn = min(end_pfn, max_low_pfn);
4303
4304        if (start_pfn < end_pfn)
4305            free_bootmem_node(NODE_DATA(this_nid),
4306                      PFN_PHYS(start_pfn),
4307                      (end_pfn - start_pfn) << PAGE_SHIFT);
4308    }
4309}
4310
4311/**
4312 * sparse_memory_present_with_active_regions - Call memory_present for each active range
4313 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
4314 *
4315 * If an architecture guarantees that all ranges registered with
4316 * add_active_ranges() contain no holes and may be freed, this
4317 * function may be used instead of calling memory_present() manually.
4318 */
4319void __init sparse_memory_present_with_active_regions(int nid)
4320{
4321    unsigned long start_pfn, end_pfn;
4322    int i, this_nid;
4323
4324    for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
4325        memory_present(this_nid, start_pfn, end_pfn);
4326}
4327
4328/**
4329 * get_pfn_range_for_nid - Return the start and end page frames for a node
4330 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
4331 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
4332 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
4333 *
4334 * It returns the start and end page frame of a node based on information
4335 * provided by an arch calling add_active_range(). If called for a node
4336 * with no available memory, a warning is printed and the start and end
4337 * PFNs will be 0.
4338 */
4339void __meminit get_pfn_range_for_nid(unsigned int nid,
4340            unsigned long *start_pfn, unsigned long *end_pfn)
4341{
4342    unsigned long this_start_pfn, this_end_pfn;
4343    int i;
4344
4345    *start_pfn = -1UL;
4346    *end_pfn = 0;
4347
4348    for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
4349        *start_pfn = min(*start_pfn, this_start_pfn);
4350        *end_pfn = max(*end_pfn, this_end_pfn);
4351    }
4352
4353    if (*start_pfn == -1UL)
4354        *start_pfn = 0;
4355}
4356
4357/*
4358 * This finds a zone that can be used for ZONE_MOVABLE pages. The
4359 * assumption is made that zones within a node are ordered in monotonic
4360 * increasing memory addresses so that the "highest" populated zone is used
4361 */
4362static void __init find_usable_zone_for_movable(void)
4363{
4364    int zone_index;
4365    for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
4366        if (zone_index == ZONE_MOVABLE)
4367            continue;
4368
4369        if (arch_zone_highest_possible_pfn[zone_index] >
4370                arch_zone_lowest_possible_pfn[zone_index])
4371            break;
4372    }
4373
4374    VM_BUG_ON(zone_index == -1);
4375    movable_zone = zone_index;
4376}
4377
4378/*
4379 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
4380 * because it is sized independent of architecture. Unlike the other zones,
4381 * the starting point for ZONE_MOVABLE is not fixed. It may be different
4382 * in each node depending on the size of each node and how evenly kernelcore
4383 * is distributed. This helper function adjusts the zone ranges
4384 * provided by the architecture for a given node by using the end of the
4385 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
4386 * zones within a node are in order of monotonic increases memory addresses
4387 */
4388static void __meminit adjust_zone_range_for_zone_movable(int nid,
4389                    unsigned long zone_type,
4390                    unsigned long node_start_pfn,
4391                    unsigned long node_end_pfn,
4392                    unsigned long *zone_start_pfn,
4393                    unsigned long *zone_end_pfn)
4394{
4395    /* Only adjust if ZONE_MOVABLE is on this node */
4396    if (zone_movable_pfn[nid]) {
4397        /* Size ZONE_MOVABLE */
4398        if (zone_type == ZONE_MOVABLE) {
4399            *zone_start_pfn = zone_movable_pfn[nid];
4400            *zone_end_pfn = min(node_end_pfn,
4401                arch_zone_highest_possible_pfn[movable_zone]);
4402
4403        /* Adjust for ZONE_MOVABLE starting within this range */
4404        } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
4405                *zone_end_pfn > zone_movable_pfn[nid]) {
4406            *zone_end_pfn = zone_movable_pfn[nid];
4407
4408        /* Check if this whole range is within ZONE_MOVABLE */
4409        } else if (*zone_start_pfn >= zone_movable_pfn[nid])
4410            *zone_start_pfn = *zone_end_pfn;
4411    }
4412}
4413
4414/*
4415 * Return the number of pages a zone spans in a node, including holes
4416 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
4417 */
4418static unsigned long __meminit zone_spanned_pages_in_node(int nid,
4419                    unsigned long zone_type,
4420                    unsigned long node_start_pfn,
4421                    unsigned long node_end_pfn,
4422                    unsigned long *ignored)
4423{
4424    unsigned long zone_start_pfn, zone_end_pfn;
4425
4426    /* Get the start and end of the zone */
4427    zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
4428    zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
4429    adjust_zone_range_for_zone_movable(nid, zone_type,
4430                node_start_pfn, node_end_pfn,
4431                &zone_start_pfn, &zone_end_pfn);
4432
4433    /* Check that this node has pages within the zone's required range */
4434    if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
4435        return 0;
4436
4437    /* Move the zone boundaries inside the node if necessary */
4438    zone_end_pfn = min(zone_end_pfn, node_end_pfn);
4439    zone_start_pfn = max(zone_start_pfn, node_start_pfn);
4440
4441    /* Return the spanned pages */
4442    return zone_end_pfn - zone_start_pfn;
4443}
4444
4445/*
4446 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
4447 * then all holes in the requested range will be accounted for.
4448 */
4449unsigned long __meminit __absent_pages_in_range(int nid,
4450                unsigned long range_start_pfn,
4451                unsigned long range_end_pfn)
4452{
4453    unsigned long nr_absent = range_end_pfn - range_start_pfn;
4454    unsigned long start_pfn, end_pfn;
4455    int i;
4456
4457    for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
4458        start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
4459        end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
4460        nr_absent -= end_pfn - start_pfn;
4461    }
4462    return nr_absent;
4463}
4464
4465/**
4466 * absent_pages_in_range - Return number of page frames in holes within a range
4467 * @start_pfn: The start PFN to start searching for holes
4468 * @end_pfn: The end PFN to stop searching for holes
4469 *
4470 * It returns the number of pages frames in memory holes within a range.
4471 */
4472unsigned long __init absent_pages_in_range(unsigned long start_pfn,
4473                            unsigned long end_pfn)
4474{
4475    return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
4476}
4477
4478/* Return the number of page frames in holes in a zone on a node */
4479static unsigned long __meminit zone_absent_pages_in_node(int nid,
4480                    unsigned long zone_type,
4481                    unsigned long node_start_pfn,
4482                    unsigned long node_end_pfn,
4483                    unsigned long *ignored)
4484{
4485    unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
4486    unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
4487    unsigned long zone_start_pfn, zone_end_pfn;
4488
4489    zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
4490    zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
4491
4492    adjust_zone_range_for_zone_movable(nid, zone_type,
4493            node_start_pfn, node_end_pfn,
4494            &zone_start_pfn, &zone_end_pfn);
4495    return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
4496}
4497
4498#else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4499static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
4500                    unsigned long zone_type,
4501                    unsigned long node_start_pfn,
4502                    unsigned long node_end_pfn,
4503                    unsigned long *zones_size)
4504{
4505    return zones_size[zone_type];
4506}
4507
4508static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
4509                        unsigned long zone_type,
4510                        unsigned long node_start_pfn,
4511                        unsigned long node_end_pfn,
4512                        unsigned long *zholes_size)
4513{
4514    if (!zholes_size)
4515        return 0;
4516
4517    return zholes_size[zone_type];
4518}
4519
4520#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4521
4522static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
4523                        unsigned long node_start_pfn,
4524                        unsigned long node_end_pfn,
4525                        unsigned long *zones_size,
4526                        unsigned long *zholes_size)
4527{
4528    unsigned long realtotalpages, totalpages = 0;
4529    enum zone_type i;
4530
4531    for (i = 0; i < MAX_NR_ZONES; i++)
4532        totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
4533                             node_start_pfn,
4534                             node_end_pfn,
4535                             zones_size);
4536    pgdat->node_spanned_pages = totalpages;
4537
4538    realtotalpages = totalpages;
4539    for (i = 0; i < MAX_NR_ZONES; i++)
4540        realtotalpages -=
4541            zone_absent_pages_in_node(pgdat->node_id, i,
4542                          node_start_pfn, node_end_pfn,
4543                          zholes_size);
4544    pgdat->node_present_pages = realtotalpages;
4545    printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
4546                            realtotalpages);
4547}
4548
4549#ifndef CONFIG_SPARSEMEM
4550/*
4551 * Calculate the size of the zone->blockflags rounded to an unsigned long
4552 * Start by making sure zonesize is a multiple of pageblock_order by rounding
4553 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
4554 * round what is now in bits to nearest long in bits, then return it in
4555 * bytes.
4556 */
4557static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
4558{
4559    unsigned long usemapsize;
4560
4561    zonesize += zone_start_pfn & (pageblock_nr_pages-1);
4562    usemapsize = roundup(zonesize, pageblock_nr_pages);
4563    usemapsize = usemapsize >> pageblock_order;
4564    usemapsize *= NR_PAGEBLOCK_BITS;
4565    usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
4566
4567    return usemapsize / 8;
4568}
4569
4570static void __init setup_usemap(struct pglist_data *pgdat,
4571                struct zone *zone,
4572                unsigned long zone_start_pfn,
4573                unsigned long zonesize)
4574{
4575    unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
4576    zone->pageblock_flags = NULL;
4577    if (usemapsize)
4578        zone->pageblock_flags = alloc_bootmem_node_nopanic(pgdat,
4579                                   usemapsize);
4580}
4581#else
4582static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
4583                unsigned long zone_start_pfn, unsigned long zonesize) {}
4584#endif /* CONFIG_SPARSEMEM */
4585
4586#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
4587
4588/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
4589void __init set_pageblock_order(void)
4590{
4591    unsigned int order;
4592
4593    /* Check that pageblock_nr_pages has not already been setup */
4594    if (pageblock_order)
4595        return;
4596
4597    if (HPAGE_SHIFT > PAGE_SHIFT)
4598        order = HUGETLB_PAGE_ORDER;
4599    else
4600        order = MAX_ORDER - 1;
4601
4602    /*
4603     * Assume the largest contiguous order of interest is a huge page.
4604     * This value may be variable depending on boot parameters on IA64 and
4605     * powerpc.
4606     */
4607    pageblock_order = order;
4608}
4609#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4610
4611/*
4612 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
4613 * is unused as pageblock_order is set at compile-time. See
4614 * include/linux/pageblock-flags.h for the values of pageblock_order based on
4615 * the kernel config
4616 */
4617void __init set_pageblock_order(void)
4618{
4619}
4620
4621#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4622
4623static unsigned long __paginginit calc_memmap_size(unsigned long spanned_pages,
4624                           unsigned long present_pages)
4625{
4626    unsigned long pages = spanned_pages;
4627
4628    /*
4629     * Provide a more accurate estimation if there are holes within
4630     * the zone and SPARSEMEM is in use. If there are holes within the
4631     * zone, each populated memory region may cost us one or two extra
4632     * memmap pages due to alignment because memmap pages for each
4633     * populated regions may not naturally algined on page boundary.
4634     * So the (present_pages >> 4) heuristic is a tradeoff for that.
4635     */
4636    if (spanned_pages > present_pages + (present_pages >> 4) &&
4637        IS_ENABLED(CONFIG_SPARSEMEM))
4638        pages = present_pages;
4639
4640    return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
4641}
4642
4643/*
4644 * Set up the zone data structures:
4645 * - mark all pages reserved
4646 * - mark all memory queues empty
4647 * - clear the memory bitmaps
4648 *
4649 * NOTE: pgdat should get zeroed by caller.
4650 */
4651static void __paginginit free_area_init_core(struct pglist_data *pgdat,
4652        unsigned long node_start_pfn, unsigned long node_end_pfn,
4653        unsigned long *zones_size, unsigned long *zholes_size)
4654{
4655    enum zone_type j;
4656    int nid = pgdat->node_id;
4657    unsigned long zone_start_pfn = pgdat->node_start_pfn;
4658    int ret;
4659
4660    pgdat_resize_init(pgdat);
4661#ifdef CONFIG_NUMA_BALANCING
4662    spin_lock_init(&pgdat->numabalancing_migrate_lock);
4663    pgdat->numabalancing_migrate_nr_pages = 0;
4664    pgdat->numabalancing_migrate_next_window = jiffies;
4665#endif
4666    init_waitqueue_head(&pgdat->kswapd_wait);
4667    init_waitqueue_head(&pgdat->pfmemalloc_wait);
4668    pgdat_page_cgroup_init(pgdat);
4669
4670    for (j = 0; j < MAX_NR_ZONES; j++) {
4671        struct zone *zone = pgdat->node_zones + j;
4672        unsigned long size, realsize, freesize, memmap_pages;
4673
4674        size = zone_spanned_pages_in_node(nid, j, node_start_pfn,
4675                          node_end_pfn, zones_size);
4676        realsize = freesize = size - zone_absent_pages_in_node(nid, j,
4677                                node_start_pfn,
4678                                node_end_pfn,
4679                                zholes_size);
4680
4681        /*
4682         * Adjust freesize so that it accounts for how much memory
4683         * is used by this zone for memmap. This affects the watermark
4684         * and per-cpu initialisations
4685         */
4686        memmap_pages = calc_memmap_size(size, realsize);
4687        if (freesize >= memmap_pages) {
4688            freesize -= memmap_pages;
4689            if (memmap_pages)
4690                printk(KERN_DEBUG
4691                       " %s zone: %lu pages used for memmap\n",
4692                       zone_names[j], memmap_pages);
4693        } else
4694            printk(KERN_WARNING
4695                " %s zone: %lu pages exceeds freesize %lu\n",
4696                zone_names[j], memmap_pages, freesize);
4697
4698        /* Account for reserved pages */
4699        if (j == 0 && freesize > dma_reserve) {
4700            freesize -= dma_reserve;
4701            printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
4702                    zone_names[0], dma_reserve);
4703        }
4704
4705        if (!is_highmem_idx(j))
4706            nr_kernel_pages += freesize;
4707        /* Charge for highmem memmap if there are enough kernel pages */
4708        else if (nr_kernel_pages > memmap_pages * 2)
4709            nr_kernel_pages -= memmap_pages;
4710        nr_all_pages += freesize;
4711
4712        zone->spanned_pages = size;
4713        zone->present_pages = realsize;
4714        /*
4715         * Set an approximate value for lowmem here, it will be adjusted
4716         * when the bootmem allocator frees pages into the buddy system.
4717         * And all highmem pages will be managed by the buddy system.
4718         */
4719        zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
4720#ifdef CONFIG_NUMA
4721        zone->node = nid;
4722        zone->min_unmapped_pages = (freesize*sysctl_min_unmapped_ratio)
4723                        / 100;
4724        zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100;
4725#endif
4726        zone->name = zone_names[j];
4727        spin_lock_init(&zone->lock);
4728        spin_lock_init(&zone->lru_lock);
4729        zone_seqlock_init(zone);
4730        zone->zone_pgdat = pgdat;
4731
4732        zone_pcp_init(zone);
4733        lruvec_init(&zone->lruvec);
4734        if (!size)
4735            continue;
4736
4737        set_pageblock_order();
4738        setup_usemap(pgdat, zone, zone_start_pfn, size);
4739        ret = init_currently_empty_zone(zone, zone_start_pfn,
4740                        size, MEMMAP_EARLY);
4741        BUG_ON(ret);
4742        memmap_init(size, nid, j, zone_start_pfn);
4743        zone_start_pfn += size;
4744    }
4745}
4746
4747static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
4748{
4749    /* Skip empty nodes */
4750    if (!pgdat->node_spanned_pages)
4751        return;
4752
4753#ifdef CONFIG_FLAT_NODE_MEM_MAP
4754    /* ia64 gets its own node_mem_map, before this, without bootmem */
4755    if (!pgdat->node_mem_map) {
4756        unsigned long size, start, end;
4757        struct page *map;
4758
4759        /*
4760         * The zone's endpoints aren't required to be MAX_ORDER
4761         * aligned but the node_mem_map endpoints must be in order
4762         * for the buddy allocator to function correctly.
4763         */
4764        start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
4765        end = pgdat_end_pfn(pgdat);
4766        end = ALIGN(end, MAX_ORDER_NR_PAGES);
4767        size = (end - start) * sizeof(struct page);
4768        map = alloc_remap(pgdat->node_id, size);
4769        if (!map)
4770            map = alloc_bootmem_node_nopanic(pgdat, size);
4771        pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
4772    }
4773#ifndef CONFIG_NEED_MULTIPLE_NODES
4774    /*
4775     * With no DISCONTIG, the global mem_map is just set as node 0's
4776     */
4777    if (pgdat == NODE_DATA(0)) {
4778        mem_map = NODE_DATA(0)->node_mem_map;
4779#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4780        if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
4781            mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
4782#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4783    }
4784#endif
4785#endif /* CONFIG_FLAT_NODE_MEM_MAP */
4786}
4787
4788void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
4789        unsigned long node_start_pfn, unsigned long *zholes_size)
4790{
4791    pg_data_t *pgdat = NODE_DATA(nid);
4792    unsigned long start_pfn = 0;
4793    unsigned long end_pfn = 0;
4794
4795    /* pg_data_t should be reset to zero when it's allocated */
4796    WARN_ON(pgdat->nr_zones || pgdat->classzone_idx);
4797
4798    pgdat->node_id = nid;
4799    pgdat->node_start_pfn = node_start_pfn;
4800    init_zone_allows_reclaim(nid);
4801#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4802    get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
4803#endif
4804    calculate_node_totalpages(pgdat, start_pfn, end_pfn,
4805                  zones_size, zholes_size);
4806
4807    alloc_node_mem_map(pgdat);
4808#ifdef CONFIG_FLAT_NODE_MEM_MAP
4809    printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
4810        nid, (unsigned long)pgdat,
4811        (unsigned long)pgdat->node_mem_map);
4812#endif
4813
4814    free_area_init_core(pgdat, start_pfn, end_pfn,
4815                zones_size, zholes_size);
4816}
4817
4818#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4819
4820#if MAX_NUMNODES > 1
4821/*
4822 * Figure out the number of possible node ids.
4823 */
4824void __init setup_nr_node_ids(void)
4825{
4826    unsigned int node;
4827    unsigned int highest = 0;
4828
4829    for_each_node_mask(node, node_possible_map)
4830        highest = node;
4831    nr_node_ids = highest + 1;
4832}
4833#endif
4834
4835/**
4836 * node_map_pfn_alignment - determine the maximum internode alignment
4837 *
4838 * This function should be called after node map is populated and sorted.
4839 * It calculates the maximum power of two alignment which can distinguish
4840 * all the nodes.
4841 *
4842 * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
4843 * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)). If the
4844 * nodes are shifted by 256MiB, 256MiB. Note that if only the last node is
4845 * shifted, 1GiB is enough and this function will indicate so.
4846 *
4847 * This is used to test whether pfn -> nid mapping of the chosen memory
4848 * model has fine enough granularity to avoid incorrect mapping for the
4849 * populated node map.
4850 *
4851 * Returns the determined alignment in pfn's. 0 if there is no alignment
4852 * requirement (single node).
4853 */
4854unsigned long __init node_map_pfn_alignment(void)
4855{
4856    unsigned long accl_mask = 0, last_end = 0;
4857    unsigned long start, end, mask;
4858    int last_nid = -1;
4859    int i, nid;
4860
4861    for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
4862        if (!start || last_nid < 0 || last_nid == nid) {
4863            last_nid = nid;
4864            last_end = end;
4865            continue;
4866        }
4867
4868        /*
4869         * Start with a mask granular enough to pin-point to the
4870         * start pfn and tick off bits one-by-one until it becomes
4871         * too coarse to separate the current node from the last.
4872         */
4873        mask = ~((1 << __ffs(start)) - 1);
4874        while (mask && last_end <= (start & (mask << 1)))
4875            mask <<= 1;
4876
4877        /* accumulate all internode masks */
4878        accl_mask |= mask;
4879    }
4880
4881    /* convert mask to number of pages */
4882    return ~accl_mask + 1;
4883}
4884
4885/* Find the lowest pfn for a node */
4886static unsigned long __init find_min_pfn_for_node(int nid)
4887{
4888    unsigned long min_pfn = ULONG_MAX;
4889    unsigned long start_pfn;
4890    int i;
4891
4892    for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
4893        min_pfn = min(min_pfn, start_pfn);
4894
4895    if (min_pfn == ULONG_MAX) {
4896        printk(KERN_WARNING
4897            "Could not find start_pfn for node %d\n", nid);
4898        return 0;
4899    }
4900
4901    return min_pfn;
4902}
4903
4904/**
4905 * find_min_pfn_with_active_regions - Find the minimum PFN registered
4906 *
4907 * It returns the minimum PFN based on information provided via
4908 * add_active_range().
4909 */
4910unsigned long __init find_min_pfn_with_active_regions(void)
4911{
4912    return find_min_pfn_for_node(MAX_NUMNODES);
4913}
4914
4915/*
4916 * early_calculate_totalpages()
4917 * Sum pages in active regions for movable zone.
4918 * Populate N_MEMORY for calculating usable_nodes.
4919 */
4920static unsigned long __init early_calculate_totalpages(void)
4921{
4922    unsigned long totalpages = 0;
4923    unsigned long start_pfn, end_pfn;
4924    int i, nid;
4925
4926    for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
4927        unsigned long pages = end_pfn - start_pfn;
4928
4929        totalpages += pages;
4930        if (pages)
4931            node_set_state(nid, N_MEMORY);
4932    }
4933      return totalpages;
4934}
4935
4936/*
4937 * Find the PFN the Movable zone begins in each node. Kernel memory
4938 * is spread evenly between nodes as long as the nodes have enough
4939 * memory. When they don't, some nodes will have more kernelcore than
4940 * others
4941 */
4942static void __init find_zone_movable_pfns_for_nodes(void)
4943{
4944    int i, nid;
4945    unsigned long usable_startpfn;
4946    unsigned long kernelcore_node, kernelcore_remaining;
4947    /* save the state before borrow the nodemask */
4948    nodemask_t saved_node_state = node_states[N_MEMORY];
4949    unsigned long totalpages = early_calculate_totalpages();
4950    int usable_nodes = nodes_weight(node_states[N_MEMORY]);
4951
4952    /*
4953     * If movablecore was specified, calculate what size of
4954     * kernelcore that corresponds so that memory usable for
4955     * any allocation type is evenly spread. If both kernelcore
4956     * and movablecore are specified, then the value of kernelcore
4957     * will be used for required_kernelcore if it's greater than
4958     * what movablecore would have allowed.
4959     */
4960    if (required_movablecore) {
4961        unsigned long corepages;
4962
4963        /*
4964         * Round-up so that ZONE_MOVABLE is at least as large as what
4965         * was requested by the user
4966         */
4967        required_movablecore =
4968            roundup(required_movablecore, MAX_ORDER_NR_PAGES);
4969        corepages = totalpages - required_movablecore;
4970
4971        required_kernelcore = max(required_kernelcore, corepages);
4972    }
4973
4974    /* If kernelcore was not specified, there is no ZONE_MOVABLE */
4975    if (!required_kernelcore)
4976        goto out;
4977
4978    /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
4979    find_usable_zone_for_movable();
4980    usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
4981
4982restart:
4983    /* Spread kernelcore memory as evenly as possible throughout nodes */
4984    kernelcore_node = required_kernelcore / usable_nodes;
4985    for_each_node_state(nid, N_MEMORY) {
4986        unsigned long start_pfn, end_pfn;
4987
4988        /*
4989         * Recalculate kernelcore_node if the division per node
4990         * now exceeds what is necessary to satisfy the requested
4991         * amount of memory for the kernel
4992         */
4993        if (required_kernelcore < kernelcore_node)
4994            kernelcore_node = required_kernelcore / usable_nodes;
4995
4996        /*
4997         * As the map is walked, we track how much memory is usable
4998         * by the kernel using kernelcore_remaining. When it is
4999         * 0, the rest of the node is usable by ZONE_MOVABLE
5000         */
5001        kernelcore_remaining = kernelcore_node;
5002
5003        /* Go through each range of PFNs within this node */
5004        for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
5005            unsigned long size_pages;
5006
5007            start_pfn = max(start_pfn, zone_movable_pfn[nid]);
5008            if (start_pfn >= end_pfn)
5009                continue;
5010
5011            /* Account for what is only usable for kernelcore */
5012            if (start_pfn < usable_startpfn) {
5013                unsigned long kernel_pages;
5014                kernel_pages = min(end_pfn, usable_startpfn)
5015                                - start_pfn;
5016
5017                kernelcore_remaining -= min(kernel_pages,
5018                            kernelcore_remaining);
5019                required_kernelcore -= min(kernel_pages,
5020                            required_kernelcore);
5021
5022                /* Continue if range is now fully accounted */
5023                if (end_pfn <= usable_startpfn) {
5024
5025                    /*
5026                     * Push zone_movable_pfn to the end so
5027                     * that if we have to rebalance
5028                     * kernelcore across nodes, we will
5029                     * not double account here
5030                     */
5031                    zone_movable_pfn[nid] = end_pfn;
5032                    continue;
5033                }
5034                start_pfn = usable_startpfn;
5035            }
5036
5037            /*
5038             * The usable PFN range for ZONE_MOVABLE is from
5039             * start_pfn->end_pfn. Calculate size_pages as the
5040             * number of pages used as kernelcore
5041             */
5042            size_pages = end_pfn - start_pfn;
5043            if (size_pages > kernelcore_remaining)
5044                size_pages = kernelcore_remaining;
5045            zone_movable_pfn[nid] = start_pfn + size_pages;
5046
5047            /*
5048             * Some kernelcore has been met, update counts and
5049             * break if the kernelcore for this node has been
5050             * satisified
5051             */
5052            required_kernelcore -= min(required_kernelcore,
5053                                size_pages);
5054            kernelcore_remaining -= size_pages;
5055            if (!kernelcore_remaining)
5056                break;
5057        }
5058    }
5059
5060    /*
5061     * If there is still required_kernelcore, we do another pass with one
5062     * less node in the count. This will push zone_movable_pfn[nid] further
5063     * along on the nodes that still have memory until kernelcore is
5064     * satisified
5065     */
5066    usable_nodes--;
5067    if (usable_nodes && required_kernelcore > usable_nodes)
5068        goto restart;
5069
5070    /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
5071    for (nid = 0; nid < MAX_NUMNODES; nid++)
5072        zone_movable_pfn[nid] =
5073            roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
5074
5075out:
5076    /* restore the node_state */
5077    node_states[N_MEMORY] = saved_node_state;
5078}
5079
5080/* Any regular or high memory on that node ? */
5081static void check_for_memory(pg_data_t *pgdat, int nid)
5082{
5083    enum zone_type zone_type;
5084
5085    if (N_MEMORY == N_NORMAL_MEMORY)
5086        return;
5087
5088    for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
5089        struct zone *zone = &pgdat->node_zones[zone_type];
5090        if (zone->present_pages) {
5091            node_set_state(nid, N_HIGH_MEMORY);
5092            if (N_NORMAL_MEMORY != N_HIGH_MEMORY &&
5093                zone_type <= ZONE_NORMAL)
5094                node_set_state(nid, N_NORMAL_MEMORY);
5095            break;
5096        }
5097    }
5098}
5099
5100/**
5101 * free_area_init_nodes - Initialise all pg_data_t and zone data
5102 * @max_zone_pfn: an array of max PFNs for each zone
5103 *
5104 * This will call free_area_init_node() for each active node in the system.
5105 * Using the page ranges provided by add_active_range(), the size of each
5106 * zone in each node and their holes is calculated. If the maximum PFN
5107 * between two adjacent zones match, it is assumed that the zone is empty.
5108 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
5109 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
5110 * starts where the previous one ended. For example, ZONE_DMA32 starts
5111 * at arch_max_dma_pfn.
5112 */
5113void __init free_area_init_nodes(unsigned long *max_zone_pfn)
5114{
5115    unsigned long start_pfn, end_pfn;
5116    int i, nid;
5117
5118    /* Record where the zone boundaries are */
5119    memset(arch_zone_lowest_possible_pfn, 0,
5120                sizeof(arch_zone_lowest_possible_pfn));
5121    memset(arch_zone_highest_possible_pfn, 0,
5122                sizeof(arch_zone_highest_possible_pfn));
5123    arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
5124    arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
5125    for (i = 1; i < MAX_NR_ZONES; i++) {
5126        if (i == ZONE_MOVABLE)
5127            continue;
5128        arch_zone_lowest_possible_pfn[i] =
5129            arch_zone_highest_possible_pfn[i-1];
5130        arch_zone_highest_possible_pfn[i] =
5131            max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
5132    }
5133    arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
5134    arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
5135
5136    /* Find the PFNs that ZONE_MOVABLE begins at in each node */
5137    memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
5138    find_zone_movable_pfns_for_nodes();
5139
5140    /* Print out the zone ranges */
5141    printk("Zone ranges:\n");
5142    for (i = 0; i < MAX_NR_ZONES; i++) {
5143        if (i == ZONE_MOVABLE)
5144            continue;
5145        printk(KERN_CONT " %-8s ", zone_names[i]);
5146        if (arch_zone_lowest_possible_pfn[i] ==
5147                arch_zone_highest_possible_pfn[i])
5148            printk(KERN_CONT "empty\n");
5149        else
5150            printk(KERN_CONT "[mem %0#10lx-%0#10lx]\n",
5151                arch_zone_lowest_possible_pfn[i] << PAGE_SHIFT,
5152                (arch_zone_highest_possible_pfn[i]
5153                    << PAGE_SHIFT) - 1);
5154    }
5155
5156    /* Print out the PFNs ZONE_MOVABLE begins at in each node */
5157    printk("Movable zone start for each node\n");
5158    for (i = 0; i < MAX_NUMNODES; i++) {
5159        if (zone_movable_pfn[i])
5160            printk(" Node %d: %#010lx\n", i,
5161                   zone_movable_pfn[i] << PAGE_SHIFT);
5162    }
5163
5164    /* Print out the early node map */
5165    printk("Early memory node ranges\n");
5166    for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
5167        printk(" node %3d: [mem %#010lx-%#010lx]\n", nid,
5168               start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1);
5169
5170    /* Initialise every node */
5171    mminit_verify_pageflags_layout();
5172    setup_nr_node_ids();
5173    for_each_online_node(nid) {
5174        pg_data_t *pgdat = NODE_DATA(nid);
5175        free_area_init_node(nid, NULL,
5176                find_min_pfn_for_node(nid), NULL);
5177
5178        /* Any memory on that node */
5179        if (pgdat->node_present_pages)
5180            node_set_state(nid, N_MEMORY);
5181        check_for_memory(pgdat, nid);
5182    }
5183}
5184
5185static int __init cmdline_parse_core(char *p, unsigned long *core)
5186{
5187    unsigned long long coremem;
5188    if (!p)
5189        return -EINVAL;
5190
5191    coremem = memparse(p, &p);
5192    *core = coremem >> PAGE_SHIFT;
5193
5194    /* Paranoid check that UL is enough for the coremem value */
5195    WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
5196
5197    return 0;
5198}
5199
5200/*
5201 * kernelcore=size sets the amount of memory for use for allocations that
5202 * cannot be reclaimed or migrated.
5203 */
5204static int __init cmdline_parse_kernelcore(char *p)
5205{
5206    return cmdline_parse_core(p, &required_kernelcore);
5207}
5208
5209/*
5210 * movablecore=size sets the amount of memory for use for allocations that
5211 * can be reclaimed or migrated.
5212 */
5213static int __init cmdline_parse_movablecore(char *p)
5214{
5215    return cmdline_parse_core(p, &required_movablecore);
5216}
5217
5218early_param("kernelcore", cmdline_parse_kernelcore);
5219early_param("movablecore", cmdline_parse_movablecore);
5220
5221#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5222
5223void adjust_managed_page_count(struct page *page, long count)
5224{
5225    spin_lock(&managed_page_count_lock);
5226    page_zone(page)->managed_pages += count;
5227    totalram_pages += count;
5228#ifdef CONFIG_HIGHMEM
5229    if (PageHighMem(page))
5230        totalhigh_pages += count;
5231#endif
5232    spin_unlock(&managed_page_count_lock);
5233}
5234EXPORT_SYMBOL(adjust_managed_page_count);
5235
5236unsigned long free_reserved_area(void *start, void *end, int poison, char *s)
5237{
5238    void *pos;
5239    unsigned long pages = 0;
5240
5241    start = (void *)PAGE_ALIGN((unsigned long)start);
5242    end = (void *)((unsigned long)end & PAGE_MASK);
5243    for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
5244        if ((unsigned int)poison <= 0xFF)
5245            memset(pos, poison, PAGE_SIZE);
5246        free_reserved_page(virt_to_page(pos));
5247    }
5248
5249    if (pages && s)
5250        pr_info("Freeing %s memory: %ldK (%p - %p)\n",
5251            s, pages << (PAGE_SHIFT - 10), start, end);
5252
5253    return pages;
5254}
5255EXPORT_SYMBOL(free_reserved_area);
5256
5257#ifdef CONFIG_HIGHMEM
5258void free_highmem_page(struct page *page)
5259{
5260    __free_reserved_page(page);
5261    totalram_pages++;
5262    page_zone(page)->managed_pages++;
5263    totalhigh_pages++;
5264}
5265#endif
5266
5267
5268void __init mem_init_print_info(const char *str)
5269{
5270    unsigned long physpages, codesize, datasize, rosize, bss_size;
5271    unsigned long init_code_size, init_data_size;
5272
5273    physpages = get_num_physpages();
5274    codesize = _etext - _stext;
5275    datasize = _edata - _sdata;
5276    rosize = __end_rodata - __start_rodata;
5277    bss_size = __bss_stop - __bss_start;
5278    init_data_size = __init_end - __init_begin;
5279    init_code_size = _einittext - _sinittext;
5280
5281    /*
5282     * Detect special cases and adjust section sizes accordingly:
5283     * 1) .init.* may be embedded into .data sections
5284     * 2) .init.text.* may be out of [__init_begin, __init_end],
5285     * please refer to arch/tile/kernel/vmlinux.lds.S.
5286     * 3) .rodata.* may be embedded into .text or .data sections.
5287     */
5288#define adj_init_size(start, end, size, pos, adj) \
5289    if (start <= pos && pos < end && size > adj) \
5290        size -= adj;
5291
5292    adj_init_size(__init_begin, __init_end, init_data_size,
5293             _sinittext, init_code_size);
5294    adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
5295    adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
5296    adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
5297    adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
5298
5299#undef adj_init_size
5300
5301    printk("Memory: %luK/%luK available "
5302           "(%luK kernel code, %luK rwdata, %luK rodata, "
5303           "%luK init, %luK bss, %luK reserved"
5304#ifdef CONFIG_HIGHMEM
5305           ", %luK highmem"
5306#endif
5307           "%s%s)\n",
5308           nr_free_pages() << (PAGE_SHIFT-10), physpages << (PAGE_SHIFT-10),
5309           codesize >> 10, datasize >> 10, rosize >> 10,
5310           (init_data_size + init_code_size) >> 10, bss_size >> 10,
5311           (physpages - totalram_pages) << (PAGE_SHIFT-10),
5312#ifdef CONFIG_HIGHMEM
5313           totalhigh_pages << (PAGE_SHIFT-10),
5314#endif
5315           str ? ", " : "", str ? str : "");
5316}
5317
5318/**
5319 * set_dma_reserve - set the specified number of pages reserved in the first zone
5320 * @new_dma_reserve: The number of pages to mark reserved
5321 *
5322 * The per-cpu batchsize and zone watermarks are determined by present_pages.
5323 * In the DMA zone, a significant percentage may be consumed by kernel image
5324 * and other unfreeable allocations which can skew the watermarks badly. This
5325 * function may optionally be used to account for unfreeable pages in the
5326 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
5327 * smaller per-cpu batchsize.
5328 */
5329void __init set_dma_reserve(unsigned long new_dma_reserve)
5330{
5331    dma_reserve = new_dma_reserve;
5332}
5333
5334void __init free_area_init(unsigned long *zones_size)
5335{
5336    free_area_init_node(0, zones_size,
5337            __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
5338}
5339
5340static int page_alloc_cpu_notify(struct notifier_block *self,
5341                 unsigned long action, void *hcpu)
5342{
5343    int cpu = (unsigned long)hcpu;
5344
5345    if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
5346        lru_add_drain_cpu(cpu);
5347        drain_pages(cpu);
5348
5349        /*
5350         * Spill the event counters of the dead processor
5351         * into the current processors event counters.
5352         * This artificially elevates the count of the current
5353         * processor.
5354         */
5355        vm_events_fold_cpu(cpu);
5356
5357        /*
5358         * Zero the differential counters of the dead processor
5359         * so that the vm statistics are consistent.
5360         *
5361         * This is only okay since the processor is dead and cannot
5362         * race with what we are doing.
5363         */
5364        refresh_cpu_vm_stats(cpu);
5365    }
5366    return NOTIFY_OK;
5367}
5368
5369void __init page_alloc_init(void)
5370{
5371    hotcpu_notifier(page_alloc_cpu_notify, 0);
5372}
5373
5374/*
5375 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
5376 * or min_free_kbytes changes.
5377 */
5378static void calculate_totalreserve_pages(void)
5379{
5380    struct pglist_data *pgdat;
5381    unsigned long reserve_pages = 0;
5382    enum zone_type i, j;
5383
5384    for_each_online_pgdat(pgdat) {
5385        for (i = 0; i < MAX_NR_ZONES; i++) {
5386            struct zone *zone = pgdat->node_zones + i;
5387            unsigned long max = 0;
5388
5389            /* Find valid and maximum lowmem_reserve in the zone */
5390            for (j = i; j < MAX_NR_ZONES; j++) {
5391                if (zone->lowmem_reserve[j] > max)
5392                    max = zone->lowmem_reserve[j];
5393            }
5394
5395            /* we treat the high watermark as reserved pages. */
5396            max += high_wmark_pages(zone);
5397
5398            if (max > zone->managed_pages)
5399                max = zone->managed_pages;
5400            reserve_pages += max;
5401            /*
5402             * Lowmem reserves are not available to
5403             * GFP_HIGHUSER page cache allocations and
5404             * kswapd tries to balance zones to their high
5405             * watermark. As a result, neither should be
5406             * regarded as dirtyable memory, to prevent a
5407             * situation where reclaim has to clean pages
5408             * in order to balance the zones.
5409             */
5410            zone->dirty_balance_reserve = max;
5411        }
5412    }
5413    dirty_balance_reserve = reserve_pages;
5414    totalreserve_pages = reserve_pages;
5415}
5416
5417/*
5418 * setup_per_zone_lowmem_reserve - called whenever
5419 * sysctl_lower_zone_reserve_ratio changes. Ensures that each zone
5420 * has a correct pages reserved value, so an adequate number of
5421 * pages are left in the zone after a successful __alloc_pages().
5422 */
5423static void setup_per_zone_lowmem_reserve(void)
5424{
5425    struct pglist_data *pgdat;
5426    enum zone_type j, idx;
5427
5428    for_each_online_pgdat(pgdat) {
5429        for (j = 0; j < MAX_NR_ZONES; j++) {
5430            struct zone *zone = pgdat->node_zones + j;
5431            unsigned long managed_pages = zone->managed_pages;
5432
5433            zone->lowmem_reserve[j] = 0;
5434
5435            idx = j;
5436            while (idx) {
5437                struct zone *lower_zone;
5438
5439                idx--;
5440
5441                if (sysctl_lowmem_reserve_ratio[idx] < 1)
5442                    sysctl_lowmem_reserve_ratio[idx] = 1;
5443
5444                lower_zone = pgdat->node_zones + idx;
5445                lower_zone->lowmem_reserve[j] = managed_pages /
5446                    sysctl_lowmem_reserve_ratio[idx];
5447                managed_pages += lower_zone->managed_pages;
5448            }
5449        }
5450    }
5451
5452    /* update totalreserve_pages */
5453    calculate_totalreserve_pages();
5454}
5455
5456static void __setup_per_zone_wmarks(void)
5457{
5458    unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
5459    unsigned long lowmem_pages = 0;
5460    struct zone *zone;
5461    unsigned long flags;
5462
5463    /* Calculate total number of !ZONE_HIGHMEM pages */
5464    for_each_zone(zone) {
5465        if (!is_highmem(zone))
5466            lowmem_pages += zone->managed_pages;
5467    }
5468
5469    for_each_zone(zone) {
5470        u64 tmp;
5471
5472        spin_lock_irqsave(&zone->lock, flags);
5473        tmp = (u64)pages_min * zone->managed_pages;
5474        do_div(tmp, lowmem_pages);
5475        if (is_highmem(zone)) {
5476            /*
5477             * __GFP_HIGH and PF_MEMALLOC allocations usually don't
5478             * need highmem pages, so cap pages_min to a small
5479             * value here.
5480             *
5481             * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
5482             * deltas controls asynch page reclaim, and so should
5483             * not be capped for highmem.
5484             */
5485            unsigned long min_pages;
5486
5487            min_pages = zone->managed_pages / 1024;
5488            min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
5489            zone->watermark[WMARK_MIN] = min_pages;
5490        } else {
5491            /*
5492             * If it's a lowmem zone, reserve a number of pages
5493             * proportionate to the zone's size.
5494             */
5495            zone->watermark[WMARK_MIN] = tmp;
5496        }
5497
5498        zone->watermark[WMARK_LOW] = min_wmark_pages(zone) + (tmp >> 2);
5499        zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
5500
5501        setup_zone_migrate_reserve(zone);
5502        spin_unlock_irqrestore(&zone->lock, flags);
5503    }
5504
5505    /* update totalreserve_pages */
5506    calculate_totalreserve_pages();
5507}
5508
5509/**
5510 * setup_per_zone_wmarks - called when min_free_kbytes changes
5511 * or when memory is hot-{added|removed}
5512 *
5513 * Ensures that the watermark[min,low,high] values for each zone are set
5514 * correctly with respect to min_free_kbytes.
5515 */
5516void setup_per_zone_wmarks(void)
5517{
5518    mutex_lock(&zonelists_mutex);
5519    __setup_per_zone_wmarks();
5520    mutex_unlock(&zonelists_mutex);
5521}
5522
5523/*
5524 * The inactive anon list should be small enough that the VM never has to
5525 * do too much work, but large enough that each inactive page has a chance
5526 * to be referenced again before it is swapped out.
5527 *
5528 * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
5529 * INACTIVE_ANON pages on this zone's LRU, maintained by the
5530 * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
5531 * the anonymous pages are kept on the inactive list.
5532 *
5533 * total target max
5534 * memory ratio inactive anon
5535 * -------------------------------------
5536 * 10MB 1 5MB
5537 * 100MB 1 50MB
5538 * 1GB 3 250MB
5539 * 10GB 10 0.9GB
5540 * 100GB 31 3GB
5541 * 1TB 101 10GB
5542 * 10TB 320 32GB
5543 */
5544static void __meminit calculate_zone_inactive_ratio(struct zone *zone)
5545{
5546    unsigned int gb, ratio;
5547
5548    /* Zone size in gigabytes */
5549    gb = zone->managed_pages >> (30 - PAGE_SHIFT);
5550    if (gb)
5551        ratio = int_sqrt(10 * gb);
5552    else
5553        ratio = 1;
5554
5555    zone->inactive_ratio = ratio;
5556}
5557
5558static void __meminit setup_per_zone_inactive_ratio(void)
5559{
5560    struct zone *zone;
5561
5562    for_each_zone(zone)
5563        calculate_zone_inactive_ratio(zone);
5564}
5565
5566/*
5567 * Initialise min_free_kbytes.
5568 *
5569 * For small machines we want it small (128k min). For large machines
5570 * we want it large (64MB max). But it is not linear, because network
5571 * bandwidth does not increase linearly with machine size. We use
5572 *
5573 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
5574 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
5575 *
5576 * which yields
5577 *
5578 * 16MB: 512k
5579 * 32MB: 724k
5580 * 64MB: 1024k
5581 * 128MB: 1448k
5582 * 256MB: 2048k
5583 * 512MB: 2896k
5584 * 1024MB: 4096k
5585 * 2048MB: 5792k
5586 * 4096MB: 8192k
5587 * 8192MB: 11584k
5588 * 16384MB: 16384k
5589 */
5590int __meminit init_per_zone_wmark_min(void)
5591{
5592    unsigned long lowmem_kbytes;
5593    int new_min_free_kbytes;
5594
5595    lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
5596    new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
5597
5598    if (new_min_free_kbytes > user_min_free_kbytes) {
5599        min_free_kbytes = new_min_free_kbytes;
5600        if (min_free_kbytes < 128)
5601            min_free_kbytes = 128;
5602        if (min_free_kbytes > 65536)
5603            min_free_kbytes = 65536;
5604    } else {
5605        pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
5606                new_min_free_kbytes, user_min_free_kbytes);
5607    }
5608    setup_per_zone_wmarks();
5609    refresh_zone_stat_thresholds();
5610    setup_per_zone_lowmem_reserve();
5611    setup_per_zone_inactive_ratio();
5612    return 0;
5613}
5614module_init(init_per_zone_wmark_min)
5615
5616/*
5617 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
5618 * that we can call two helper functions whenever min_free_kbytes
5619 * changes.
5620 */
5621int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
5622    void __user *buffer, size_t *length, loff_t *ppos)
5623{
5624    proc_dointvec(table, write, buffer, length, ppos);
5625    if (write) {
5626        user_min_free_kbytes = min_free_kbytes;
5627        setup_per_zone_wmarks();
5628    }
5629    return 0;
5630}
5631
5632#ifdef CONFIG_NUMA
5633int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
5634    void __user *buffer, size_t *length, loff_t *ppos)
5635{
5636    struct zone *zone;
5637    int rc;
5638
5639    rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5640    if (rc)
5641        return rc;
5642
5643    for_each_zone(zone)
5644        zone->min_unmapped_pages = (zone->managed_pages *
5645                sysctl_min_unmapped_ratio) / 100;
5646    return 0;
5647}
5648
5649int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
5650    void __user *buffer, size_t *length, loff_t *ppos)
5651{
5652    struct zone *zone;
5653    int rc;
5654
5655    rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5656    if (rc)
5657        return rc;
5658
5659    for_each_zone(zone)
5660        zone->min_slab_pages = (zone->managed_pages *
5661                sysctl_min_slab_ratio) / 100;
5662    return 0;
5663}
5664#endif
5665
5666/*
5667 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
5668 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
5669 * whenever sysctl_lowmem_reserve_ratio changes.
5670 *
5671 * The reserve ratio obviously has absolutely no relation with the
5672 * minimum watermarks. The lowmem reserve ratio can only make sense
5673 * if in function of the boot time zone sizes.
5674 */
5675int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
5676    void __user *buffer, size_t *length, loff_t *ppos)
5677{
5678    proc_dointvec_minmax(table, write, buffer, length, ppos);
5679    setup_per_zone_lowmem_reserve();
5680    return 0;
5681}
5682
5683/*
5684 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
5685 * cpu. It is the fraction of total pages in each zone that a hot per cpu pagelist
5686 * can have before it gets flushed back to buddy allocator.
5687 */
5688int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
5689    void __user *buffer, size_t *length, loff_t *ppos)
5690{
5691    struct zone *zone;
5692    unsigned int cpu;
5693    int ret;
5694
5695    ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
5696    if (!write || (ret < 0))
5697        return ret;
5698
5699    mutex_lock(&pcp_batch_high_lock);
5700    for_each_populated_zone(zone) {
5701        unsigned long high;
5702        high = zone->managed_pages / percpu_pagelist_fraction;
5703        for_each_possible_cpu(cpu)
5704            pageset_set_high(per_cpu_ptr(zone->pageset, cpu),
5705                     high);
5706    }
5707    mutex_unlock(&pcp_batch_high_lock);
5708    return 0;
5709}
5710
5711int hashdist = HASHDIST_DEFAULT;
5712
5713#ifdef CONFIG_NUMA
5714static int __init set_hashdist(char *str)
5715{
5716    if (!str)
5717        return 0;
5718    hashdist = simple_strtoul(str, &str, 0);
5719    return 1;
5720}
5721__setup("hashdist=", set_hashdist);
5722#endif
5723
5724/*
5725 * allocate a large system hash table from bootmem
5726 * - it is assumed that the hash table must contain an exact power-of-2
5727 * quantity of entries
5728 * - limit is the number of hash buckets, not the total allocation size
5729 */
5730void *__init alloc_large_system_hash(const char *tablename,
5731                     unsigned long bucketsize,
5732                     unsigned long numentries,
5733                     int scale,
5734                     int flags,
5735                     unsigned int *_hash_shift,
5736                     unsigned int *_hash_mask,
5737                     unsigned long low_limit,
5738                     unsigned long high_limit)
5739{
5740    unsigned long long max = high_limit;
5741    unsigned long log2qty, size;
5742    void *table = NULL;
5743
5744    /* allow the kernel cmdline to have a say */
5745    if (!numentries) {
5746        /* round applicable memory size up to nearest megabyte */
5747        numentries = nr_kernel_pages;
5748        numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
5749        numentries >>= 20 - PAGE_SHIFT;
5750        numentries <<= 20 - PAGE_SHIFT;
5751
5752        /* limit to 1 bucket per 2^scale bytes of low memory */
5753        if (scale > PAGE_SHIFT)
5754            numentries >>= (scale - PAGE_SHIFT);
5755        else
5756            numentries <<= (PAGE_SHIFT - scale);
5757
5758        /* Make sure we've got at least a 0-order allocation.. */
5759        if (unlikely(flags & HASH_SMALL)) {
5760            /* Makes no sense without HASH_EARLY */
5761            WARN_ON(!(flags & HASH_EARLY));
5762            if (!(numentries >> *_hash_shift)) {
5763                numentries = 1UL << *_hash_shift;
5764                BUG_ON(!numentries);
5765            }
5766        } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
5767            numentries = PAGE_SIZE / bucketsize;
5768    }
5769    numentries = roundup_pow_of_two(numentries);
5770
5771    /* limit allocation size to 1/16 total memory by default */
5772    if (max == 0) {
5773        max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
5774        do_div(max, bucketsize);
5775    }
5776    max = min(max, 0x80000000ULL);
5777
5778    if (numentries < low_limit)
5779        numentries = low_limit;
5780    if (numentries > max)
5781        numentries = max;
5782
5783    log2qty = ilog2(numentries);
5784
5785    do {
5786        size = bucketsize << log2qty;
5787        if (flags & HASH_EARLY)
5788            table = alloc_bootmem_nopanic(size);
5789        else if (hashdist)
5790            table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
5791        else {
5792            /*
5793             * If bucketsize is not a power-of-two, we may free
5794             * some pages at the end of hash table which
5795             * alloc_pages_exact() automatically does
5796             */
5797            if (get_order(size) < MAX_ORDER) {
5798                table = alloc_pages_exact(size, GFP_ATOMIC);
5799                kmemleak_alloc(table, size, 1, GFP_ATOMIC);
5800            }
5801        }
5802    } while (!table && size > PAGE_SIZE && --log2qty);
5803
5804    if (!table)
5805        panic("Failed to allocate %s hash table\n", tablename);
5806
5807    printk(KERN_INFO "%s hash table entries: %ld (order: %d, %lu bytes)\n",
5808           tablename,
5809           (1UL << log2qty),
5810           ilog2(size) - PAGE_SHIFT,
5811           size);
5812
5813    if (_hash_shift)
5814        *_hash_shift = log2qty;
5815    if (_hash_mask)
5816        *_hash_mask = (1 << log2qty) - 1;
5817
5818 &n