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/sched/rt.h>
62
63#include <asm/tlbflush.h>
64#include <asm/div64.h>
65#include "internal.h"
66
67#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
68DEFINE_PER_CPU(int, numa_node);
69EXPORT_PER_CPU_SYMBOL(numa_node);
70#endif
71
72#ifdef CONFIG_HAVE_MEMORYLESS_NODES
73/*
74 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
75 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
76 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
77 * defined in <linux/topology.h>.
78 */
79DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */
80EXPORT_PER_CPU_SYMBOL(_numa_mem_);
81#endif
82
83/*
84 * Array of node states.
85 */
86nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
87    [N_POSSIBLE] = NODE_MASK_ALL,
88    [N_ONLINE] = { { [0] = 1UL } },
89#ifndef CONFIG_NUMA
90    [N_NORMAL_MEMORY] = { { [0] = 1UL } },
91#ifdef CONFIG_HIGHMEM
92    [N_HIGH_MEMORY] = { { [0] = 1UL } },
93#endif
94#ifdef CONFIG_MOVABLE_NODE
95    [N_MEMORY] = { { [0] = 1UL } },
96#endif
97    [N_CPU] = { { [0] = 1UL } },
98#endif /* NUMA */
99};
100EXPORT_SYMBOL(node_states);
101
102unsigned long totalram_pages __read_mostly;
103unsigned long totalreserve_pages __read_mostly;
104/*
105 * When calculating the number of globally allowed dirty pages, there
106 * is a certain number of per-zone reserves that should not be
107 * considered dirtyable memory. This is the sum of those reserves
108 * over all existing zones that contribute dirtyable memory.
109 */
110unsigned long dirty_balance_reserve __read_mostly;
111
112int percpu_pagelist_fraction;
113gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
114
115#ifdef CONFIG_PM_SLEEP
116/*
117 * The following functions are used by the suspend/hibernate code to temporarily
118 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
119 * while devices are suspended. To avoid races with the suspend/hibernate code,
120 * they should always be called with pm_mutex held (gfp_allowed_mask also should
121 * only be modified with pm_mutex held, unless the suspend/hibernate code is
122 * guaranteed not to run in parallel with that modification).
123 */
124
125static gfp_t saved_gfp_mask;
126
127void pm_restore_gfp_mask(void)
128{
129    WARN_ON(!mutex_is_locked(&pm_mutex));
130    if (saved_gfp_mask) {
131        gfp_allowed_mask = saved_gfp_mask;
132        saved_gfp_mask = 0;
133    }
134}
135
136void pm_restrict_gfp_mask(void)
137{
138    WARN_ON(!mutex_is_locked(&pm_mutex));
139    WARN_ON(saved_gfp_mask);
140    saved_gfp_mask = gfp_allowed_mask;
141    gfp_allowed_mask &= ~GFP_IOFS;
142}
143
144bool pm_suspended_storage(void)
145{
146    if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS)
147        return false;
148    return true;
149}
150#endif /* CONFIG_PM_SLEEP */
151
152#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
153int pageblock_order __read_mostly;
154#endif
155
156static void __free_pages_ok(struct page *page, unsigned int order);
157
158/*
159 * results with 256, 32 in the lowmem_reserve sysctl:
160 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
161 * 1G machine -> (16M dma, 784M normal, 224M high)
162 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
163 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
164 * HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
165 *
166 * TBD: should special case ZONE_DMA32 machines here - in those we normally
167 * don't need any ZONE_NORMAL reservation
168 */
169int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
170#ifdef CONFIG_ZONE_DMA
171     256,
172#endif
173#ifdef CONFIG_ZONE_DMA32
174     256,
175#endif
176#ifdef CONFIG_HIGHMEM
177     32,
178#endif
179     32,
180};
181
182EXPORT_SYMBOL(totalram_pages);
183
184static char * const zone_names[MAX_NR_ZONES] = {
185#ifdef CONFIG_ZONE_DMA
186     "DMA",
187#endif
188#ifdef CONFIG_ZONE_DMA32
189     "DMA32",
190#endif
191     "Normal",
192#ifdef CONFIG_HIGHMEM
193     "HighMem",
194#endif
195     "Movable",
196};
197
198int min_free_kbytes = 1024;
199
200static unsigned long __meminitdata nr_kernel_pages;
201static unsigned long __meminitdata nr_all_pages;
202static unsigned long __meminitdata dma_reserve;
203
204#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
205static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
206static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
207static unsigned long __initdata required_kernelcore;
208static unsigned long __initdata required_movablecore;
209static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
210
211/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
212int movable_zone;
213EXPORT_SYMBOL(movable_zone);
214#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
215
216#if MAX_NUMNODES > 1
217int nr_node_ids __read_mostly = MAX_NUMNODES;
218int nr_online_nodes __read_mostly = 1;
219EXPORT_SYMBOL(nr_node_ids);
220EXPORT_SYMBOL(nr_online_nodes);
221#endif
222
223int page_group_by_mobility_disabled __read_mostly;
224
225void set_pageblock_migratetype(struct page *page, int migratetype)
226{
227
228    if (unlikely(page_group_by_mobility_disabled))
229        migratetype = MIGRATE_UNMOVABLE;
230
231    set_pageblock_flags_group(page, (unsigned long)migratetype,
232                    PB_migrate, PB_migrate_end);
233}
234
235bool oom_killer_disabled __read_mostly;
236
237#ifdef CONFIG_DEBUG_VM
238static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
239{
240    int ret = 0;
241    unsigned seq;
242    unsigned long pfn = page_to_pfn(page);
243    unsigned long sp, start_pfn;
244
245    do {
246        seq = zone_span_seqbegin(zone);
247        start_pfn = zone->zone_start_pfn;
248        sp = zone->spanned_pages;
249        if (!zone_spans_pfn(zone, pfn))
250            ret = 1;
251    } while (zone_span_seqretry(zone, seq));
252
253    if (ret)
254        pr_err("page %lu outside zone [ %lu - %lu ]\n",
255            pfn, start_pfn, start_pfn + sp);
256
257    return ret;
258}
259
260static int page_is_consistent(struct zone *zone, struct page *page)
261{
262    if (!pfn_valid_within(page_to_pfn(page)))
263        return 0;
264    if (zone != page_zone(page))
265        return 0;
266
267    return 1;
268}
269/*
270 * Temporary debugging check for pages not lying within a given zone.
271 */
272static int bad_range(struct zone *zone, struct page *page)
273{
274    if (page_outside_zone_boundaries(zone, page))
275        return 1;
276    if (!page_is_consistent(zone, page))
277        return 1;
278
279    return 0;
280}
281#else
282static inline int bad_range(struct zone *zone, struct page *page)
283{
284    return 0;
285}
286#endif
287
288static void bad_page(struct page *page)
289{
290    static unsigned long resume;
291    static unsigned long nr_shown;
292    static unsigned long nr_unshown;
293
294    /* Don't complain about poisoned pages */
295    if (PageHWPoison(page)) {
296        page_mapcount_reset(page); /* remove PageBuddy */
297        return;
298    }
299
300    /*
301     * Allow a burst of 60 reports, then keep quiet for that minute;
302     * or allow a steady drip of one report per second.
303     */
304    if (nr_shown == 60) {
305        if (time_before(jiffies, resume)) {
306            nr_unshown++;
307            goto out;
308        }
309        if (nr_unshown) {
310            printk(KERN_ALERT
311                  "BUG: Bad page state: %lu messages suppressed\n",
312                nr_unshown);
313            nr_unshown = 0;
314        }
315        nr_shown = 0;
316    }
317    if (nr_shown++ == 0)
318        resume = jiffies + 60 * HZ;
319
320    printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n",
321        current->comm, page_to_pfn(page));
322    dump_page(page);
323
324    print_modules();
325    dump_stack();
326out:
327    /* Leave bad fields for debug, except PageBuddy could make trouble */
328    page_mapcount_reset(page); /* remove PageBuddy */
329    add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
330}
331
332/*
333 * Higher-order pages are called "compound pages". They are structured thusly:
334 *
335 * The first PAGE_SIZE page is called the "head page".
336 *
337 * The remaining PAGE_SIZE pages are called "tail pages".
338 *
339 * All pages have PG_compound set. All tail pages have their ->first_page
340 * pointing at the head page.
341 *
342 * The first tail page's ->lru.next holds the address of the compound page's
343 * put_page() function. Its ->lru.prev holds the order of allocation.
344 * This usage means that zero-order pages may not be compound.
345 */
346
347static void free_compound_page(struct page *page)
348{
349    __free_pages_ok(page, compound_order(page));
350}
351
352void prep_compound_page(struct page *page, unsigned long order)
353{
354    int i;
355    int nr_pages = 1 << order;
356
357    set_compound_page_dtor(page, free_compound_page);
358    set_compound_order(page, order);
359    __SetPageHead(page);
360    for (i = 1; i < nr_pages; i++) {
361        struct page *p = page + i;
362        __SetPageTail(p);
363        set_page_count(p, 0);
364        p->first_page = page;
365    }
366}
367
368/* update __split_huge_page_refcount if you change this function */
369static int destroy_compound_page(struct page *page, unsigned long order)
370{
371    int i;
372    int nr_pages = 1 << order;
373    int bad = 0;
374
375    if (unlikely(compound_order(page) != order)) {
376        bad_page(page);
377        bad++;
378    }
379
380    __ClearPageHead(page);
381
382    for (i = 1; i < nr_pages; i++) {
383        struct page *p = page + i;
384
385        if (unlikely(!PageTail(p) || (p->first_page != page))) {
386            bad_page(page);
387            bad++;
388        }
389        __ClearPageTail(p);
390    }
391
392    return bad;
393}
394
395static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
396{
397    int i;
398
399    /*
400     * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
401     * and __GFP_HIGHMEM from hard or soft interrupt context.
402     */
403    VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
404    for (i = 0; i < (1 << order); i++)
405        clear_highpage(page + i);
406}
407
408#ifdef CONFIG_DEBUG_PAGEALLOC
409unsigned int _debug_guardpage_minorder;
410
411static int __init debug_guardpage_minorder_setup(char *buf)
412{
413    unsigned long res;
414
415    if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) {
416        printk(KERN_ERR "Bad debug_guardpage_minorder value\n");
417        return 0;
418    }
419    _debug_guardpage_minorder = res;
420    printk(KERN_INFO "Setting debug_guardpage_minorder to %lu\n", res);
421    return 0;
422}
423__setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup);
424
425static inline void set_page_guard_flag(struct page *page)
426{
427    __set_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
428}
429
430static inline void clear_page_guard_flag(struct page *page)
431{
432    __clear_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
433}
434#else
435static inline void set_page_guard_flag(struct page *page) { }
436static inline void clear_page_guard_flag(struct page *page) { }
437#endif
438
439static inline void set_page_order(struct page *page, int order)
440{
441    set_page_private(page, order);
442    __SetPageBuddy(page);
443}
444
445static inline void rmv_page_order(struct page *page)
446{
447    __ClearPageBuddy(page);
448    set_page_private(page, 0);
449}
450
451/*
452 * Locate the struct page for both the matching buddy in our
453 * pair (buddy1) and the combined O(n+1) page they form (page).
454 *
455 * 1) Any buddy B1 will have an order O twin B2 which satisfies
456 * the following equation:
457 * B2 = B1 ^ (1 << O)
458 * For example, if the starting buddy (buddy2) is #8 its order
459 * 1 buddy is #10:
460 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
461 *
462 * 2) Any buddy B will have an order O+1 parent P which
463 * satisfies the following equation:
464 * P = B & ~(1 << O)
465 *
466 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
467 */
468static inline unsigned long
469__find_buddy_index(unsigned long page_idx, unsigned int order)
470{
471    return page_idx ^ (1 << order);
472}
473
474/*
475 * This function checks whether a page is free && is the buddy
476 * we can do coalesce a page and its buddy if
477 * (a) the buddy is not in a hole &&
478 * (b) the buddy is in the buddy system &&
479 * (c) a page and its buddy have the same order &&
480 * (d) a page and its buddy are in the same zone.
481 *
482 * For recording whether a page is in the buddy system, we set ->_mapcount -2.
483 * Setting, clearing, and testing _mapcount -2 is serialized by zone->lock.
484 *
485 * For recording page's order, we use page_private(page).
486 */
487static inline int page_is_buddy(struct page *page, struct page *buddy,
488                                int order)
489{
490    if (!pfn_valid_within(page_to_pfn(buddy)))
491        return 0;
492
493    if (page_zone_id(page) != page_zone_id(buddy))
494        return 0;
495
496    if (page_is_guard(buddy) && page_order(buddy) == order) {
497        VM_BUG_ON(page_count(buddy) != 0);
498        return 1;
499    }
500
501    if (PageBuddy(buddy) && page_order(buddy) == order) {
502        VM_BUG_ON(page_count(buddy) != 0);
503        return 1;
504    }
505    return 0;
506}
507
508/*
509 * Freeing function for a buddy system allocator.
510 *
511 * The concept of a buddy system is to maintain direct-mapped table
512 * (containing bit values) for memory blocks of various "orders".
513 * The bottom level table contains the map for the smallest allocatable
514 * units of memory (here, pages), and each level above it describes
515 * pairs of units from the levels below, hence, "buddies".
516 * At a high level, all that happens here is marking the table entry
517 * at the bottom level available, and propagating the changes upward
518 * as necessary, plus some accounting needed to play nicely with other
519 * parts of the VM system.
520 * At each level, we keep a list of pages, which are heads of continuous
521 * free pages of length of (1 << order) and marked with _mapcount -2. Page's
522 * order is recorded in page_private(page) field.
523 * So when we are allocating or freeing one, we can derive the state of the
524 * other. That is, if we allocate a small block, and both were
525 * free, the remainder of the region must be split into blocks.
526 * If a block is freed, and its buddy is also free, then this
527 * triggers coalescing into a block of larger size.
528 *
529 * -- nyc
530 */
531
532static inline void __free_one_page(struct page *page,
533        struct zone *zone, unsigned int order,
534        int migratetype)
535{
536    unsigned long page_idx;
537    unsigned long combined_idx;
538    unsigned long uninitialized_var(buddy_idx);
539    struct page *buddy;
540
541    VM_BUG_ON(!zone_is_initialized(zone));
542
543    if (unlikely(PageCompound(page)))
544        if (unlikely(destroy_compound_page(page, order)))
545            return;
546
547    VM_BUG_ON(migratetype == -1);
548
549    page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
550
551    VM_BUG_ON(page_idx & ((1 << order) - 1));
552    VM_BUG_ON(bad_range(zone, page));
553
554    while (order < MAX_ORDER-1) {
555        buddy_idx = __find_buddy_index(page_idx, order);
556        buddy = page + (buddy_idx - page_idx);
557        if (!page_is_buddy(page, buddy, order))
558            break;
559        /*
560         * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
561         * merge with it and move up one order.
562         */
563        if (page_is_guard(buddy)) {
564            clear_page_guard_flag(buddy);
565            set_page_private(page, 0);
566            __mod_zone_freepage_state(zone, 1 << order,
567                          migratetype);
568        } else {
569            list_del(&buddy->lru);
570            zone->free_area[order].nr_free--;
571            rmv_page_order(buddy);
572        }
573        combined_idx = buddy_idx & page_idx;
574        page = page + (combined_idx - page_idx);
575        page_idx = combined_idx;
576        order++;
577    }
578    set_page_order(page, order);
579
580    /*
581     * If this is not the largest possible page, check if the buddy
582     * of the next-highest order is free. If it is, it's possible
583     * that pages are being freed that will coalesce soon. In case,
584     * that is happening, add the free page to the tail of the list
585     * so it's less likely to be used soon and more likely to be merged
586     * as a higher order page
587     */
588    if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
589        struct page *higher_page, *higher_buddy;
590        combined_idx = buddy_idx & page_idx;
591        higher_page = page + (combined_idx - page_idx);
592        buddy_idx = __find_buddy_index(combined_idx, order + 1);
593        higher_buddy = higher_page + (buddy_idx - combined_idx);
594        if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
595            list_add_tail(&page->lru,
596                &zone->free_area[order].free_list[migratetype]);
597            goto out;
598        }
599    }
600
601    list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
602out:
603    zone->free_area[order].nr_free++;
604}
605
606static inline int free_pages_check(struct page *page)
607{
608    if (unlikely(page_mapcount(page) |
609        (page->mapping != NULL) |
610        (atomic_read(&page->_count) != 0) |
611        (page->flags & PAGE_FLAGS_CHECK_AT_FREE) |
612        (mem_cgroup_bad_page_check(page)))) {
613        bad_page(page);
614        return 1;
615    }
616    page_nid_reset_last(page);
617    if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
618        page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
619    return 0;
620}
621
622/*
623 * Frees a number of pages from the PCP lists
624 * Assumes all pages on list are in same zone, and of same order.
625 * count is the number of pages to free.
626 *
627 * If the zone was previously in an "all pages pinned" state then look to
628 * see if this freeing clears that state.
629 *
630 * And clear the zone's pages_scanned counter, to hold off the "all pages are
631 * pinned" detection logic.
632 */
633static void free_pcppages_bulk(struct zone *zone, int count,
634                    struct per_cpu_pages *pcp)
635{
636    int migratetype = 0;
637    int batch_free = 0;
638    int to_free = count;
639
640    spin_lock(&zone->lock);
641    zone->all_unreclaimable = 0;
642    zone->pages_scanned = 0;
643
644    while (to_free) {
645        struct page *page;
646        struct list_head *list;
647
648        /*
649         * Remove pages from lists in a round-robin fashion. A
650         * batch_free count is maintained that is incremented when an
651         * empty list is encountered. This is so more pages are freed
652         * off fuller lists instead of spinning excessively around empty
653         * lists
654         */
655        do {
656            batch_free++;
657            if (++migratetype == MIGRATE_PCPTYPES)
658                migratetype = 0;
659            list = &pcp->lists[migratetype];
660        } while (list_empty(list));
661
662        /* This is the only non-empty list. Free them all. */
663        if (batch_free == MIGRATE_PCPTYPES)
664            batch_free = to_free;
665
666        do {
667            int mt; /* migratetype of the to-be-freed page */
668
669            page = list_entry(list->prev, struct page, lru);
670            /* must delete as __free_one_page list manipulates */
671            list_del(&page->lru);
672            mt = get_freepage_migratetype(page);
673            /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
674            __free_one_page(page, zone, 0, mt);
675            trace_mm_page_pcpu_drain(page, 0, mt);
676            if (likely(!is_migrate_isolate_page(page))) {
677                __mod_zone_page_state(zone, NR_FREE_PAGES, 1);
678                if (is_migrate_cma(mt))
679                    __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
680            }
681        } while (--to_free && --batch_free && !list_empty(list));
682    }
683    spin_unlock(&zone->lock);
684}
685
686static void free_one_page(struct zone *zone, struct page *page, int order,
687                int migratetype)
688{
689    spin_lock(&zone->lock);
690    zone->all_unreclaimable = 0;
691    zone->pages_scanned = 0;
692
693    __free_one_page(page, zone, order, migratetype);
694    if (unlikely(!is_migrate_isolate(migratetype)))
695        __mod_zone_freepage_state(zone, 1 << order, migratetype);
696    spin_unlock(&zone->lock);
697}
698
699static bool free_pages_prepare(struct page *page, unsigned int order)
700{
701    int i;
702    int bad = 0;
703
704    trace_mm_page_free(page, order);
705    kmemcheck_free_shadow(page, order);
706
707    if (PageAnon(page))
708        page->mapping = NULL;
709    for (i = 0; i < (1 << order); i++)
710        bad += free_pages_check(page + i);
711    if (bad)
712        return false;
713
714    if (!PageHighMem(page)) {
715        debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
716        debug_check_no_obj_freed(page_address(page),
717                       PAGE_SIZE << order);
718    }
719    arch_free_page(page, order);
720    kernel_map_pages(page, 1 << order, 0);
721
722    return true;
723}
724
725static void __free_pages_ok(struct page *page, unsigned int order)
726{
727    unsigned long flags;
728    int migratetype;
729
730    if (!free_pages_prepare(page, order))
731        return;
732
733    local_irq_save(flags);
734    __count_vm_events(PGFREE, 1 << order);
735    migratetype = get_pageblock_migratetype(page);
736    set_freepage_migratetype(page, migratetype);
737    free_one_page(page_zone(page), page, order, migratetype);
738    local_irq_restore(flags);
739}
740
741/*
742 * Read access to zone->managed_pages is safe because it's unsigned long,
743 * but we still need to serialize writers. Currently all callers of
744 * __free_pages_bootmem() except put_page_bootmem() should only be used
745 * at boot time. So for shorter boot time, we shift the burden to
746 * put_page_bootmem() to serialize writers.
747 */
748void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
749{
750    unsigned int nr_pages = 1 << order;
751    unsigned int loop;
752
753    prefetchw(page);
754    for (loop = 0; loop < nr_pages; loop++) {
755        struct page *p = &page[loop];
756
757        if (loop + 1 < nr_pages)
758            prefetchw(p + 1);
759        __ClearPageReserved(p);
760        set_page_count(p, 0);
761    }
762
763    page_zone(page)->managed_pages += 1 << order;
764    set_page_refcounted(page);
765    __free_pages(page, order);
766}
767
768#ifdef CONFIG_CMA
769/* Free whole pageblock and set it's migration type to MIGRATE_CMA. */
770void __init init_cma_reserved_pageblock(struct page *page)
771{
772    unsigned i = pageblock_nr_pages;
773    struct page *p = page;
774
775    do {
776        __ClearPageReserved(p);
777        set_page_count(p, 0);
778    } while (++p, --i);
779
780    set_page_refcounted(page);
781    set_pageblock_migratetype(page, MIGRATE_CMA);
782    __free_pages(page, pageblock_order);
783    totalram_pages += pageblock_nr_pages;
784#ifdef CONFIG_HIGHMEM
785    if (PageHighMem(page))
786        totalhigh_pages += pageblock_nr_pages;
787#endif
788}
789#endif
790
791/*
792 * The order of subdivision here is critical for the IO subsystem.
793 * Please do not alter this order without good reasons and regression
794 * testing. Specifically, as large blocks of memory are subdivided,
795 * the order in which smaller blocks are delivered depends on the order
796 * they're subdivided in this function. This is the primary factor
797 * influencing the order in which pages are delivered to the IO
798 * subsystem according to empirical testing, and this is also justified
799 * by considering the behavior of a buddy system containing a single
800 * large block of memory acted on by a series of small allocations.
801 * This behavior is a critical factor in sglist merging's success.
802 *
803 * -- nyc
804 */
805static inline void expand(struct zone *zone, struct page *page,
806    int low, int high, struct free_area *area,
807    int migratetype)
808{
809    unsigned long size = 1 << high;
810
811    while (high > low) {
812        area--;
813        high--;
814        size >>= 1;
815        VM_BUG_ON(bad_range(zone, &page[size]));
816
817#ifdef CONFIG_DEBUG_PAGEALLOC
818        if (high < debug_guardpage_minorder()) {
819            /*
820             * Mark as guard pages (or page), that will allow to
821             * merge back to allocator when buddy will be freed.
822             * Corresponding page table entries will not be touched,
823             * pages will stay not present in virtual address space
824             */
825            INIT_LIST_HEAD(&page[size].lru);
826            set_page_guard_flag(&page[size]);
827            set_page_private(&page[size], high);
828            /* Guard pages are not available for any usage */
829            __mod_zone_freepage_state(zone, -(1 << high),
830                          migratetype);
831            continue;
832        }
833#endif
834        list_add(&page[size].lru, &area->free_list[migratetype]);
835        area->nr_free++;
836        set_page_order(&page[size], high);
837    }
838}
839
840/*
841 * This page is about to be returned from the page allocator
842 */
843static inline int check_new_page(struct page *page)
844{
845    if (unlikely(page_mapcount(page) |
846        (page->mapping != NULL) |
847        (atomic_read(&page->_count) != 0) |
848        (page->flags & PAGE_FLAGS_CHECK_AT_PREP) |
849        (mem_cgroup_bad_page_check(page)))) {
850        bad_page(page);
851        return 1;
852    }
853    return 0;
854}
855
856static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
857{
858    int i;
859
860    for (i = 0; i < (1 << order); i++) {
861        struct page *p = page + i;
862        if (unlikely(check_new_page(p)))
863            return 1;
864    }
865
866    set_page_private(page, 0);
867    set_page_refcounted(page);
868
869    arch_alloc_page(page, order);
870    kernel_map_pages(page, 1 << order, 1);
871
872    if (gfp_flags & __GFP_ZERO)
873        prep_zero_page(page, order, gfp_flags);
874
875    if (order && (gfp_flags & __GFP_COMP))
876        prep_compound_page(page, order);
877
878    return 0;
879}
880
881/*
882 * Go through the free lists for the given migratetype and remove
883 * the smallest available page from the freelists
884 */
885static inline
886struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
887                        int migratetype)
888{
889    unsigned int current_order;
890    struct free_area * area;
891    struct page *page;
892
893    /* Find a page of the appropriate size in the preferred list */
894    for (current_order = order; current_order < MAX_ORDER; ++current_order) {
895        area = &(zone->free_area[current_order]);
896        if (list_empty(&area->free_list[migratetype]))
897            continue;
898
899        page = list_entry(area->free_list[migratetype].next,
900                            struct page, lru);
901        list_del(&page->lru);
902        rmv_page_order(page);
903        area->nr_free--;
904        expand(zone, page, order, current_order, area, migratetype);
905        return page;
906    }
907
908    return NULL;
909}
910
911
912/*
913 * This array describes the order lists are fallen back to when
914 * the free lists for the desirable migrate type are depleted
915 */
916static int fallbacks[MIGRATE_TYPES][4] = {
917    [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
918    [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
919#ifdef CONFIG_CMA
920    [MIGRATE_MOVABLE] = { MIGRATE_CMA, MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
921    [MIGRATE_CMA] = { MIGRATE_RESERVE }, /* Never used */
922#else
923    [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
924#endif
925    [MIGRATE_RESERVE] = { MIGRATE_RESERVE }, /* Never used */
926#ifdef CONFIG_MEMORY_ISOLATION
927    [MIGRATE_ISOLATE] = { MIGRATE_RESERVE }, /* Never used */
928#endif
929};
930
931/*
932 * Move the free pages in a range to the free lists of the requested type.
933 * Note that start_page and end_pages are not aligned on a pageblock
934 * boundary. If alignment is required, use move_freepages_block()
935 */
936int move_freepages(struct zone *zone,
937              struct page *start_page, struct page *end_page,
938              int migratetype)
939{
940    struct page *page;
941    unsigned long order;
942    int pages_moved = 0;
943
944#ifndef CONFIG_HOLES_IN_ZONE
945    /*
946     * page_zone is not safe to call in this context when
947     * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
948     * anyway as we check zone boundaries in move_freepages_block().
949     * Remove at a later date when no bug reports exist related to
950     * grouping pages by mobility
951     */
952    BUG_ON(page_zone(start_page) != page_zone(end_page));
953#endif
954
955    for (page = start_page; page <= end_page;) {
956        /* Make sure we are not inadvertently changing nodes */
957        VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
958
959        if (!pfn_valid_within(page_to_pfn(page))) {
960            page++;
961            continue;
962        }
963
964        if (!PageBuddy(page)) {
965            page++;
966            continue;
967        }
968
969        order = page_order(page);
970        list_move(&page->lru,
971              &zone->free_area[order].free_list[migratetype]);
972        set_freepage_migratetype(page, migratetype);
973        page += 1 << order;
974        pages_moved += 1 << order;
975    }
976
977    return pages_moved;
978}
979
980int move_freepages_block(struct zone *zone, struct page *page,
981                int migratetype)
982{
983    unsigned long start_pfn, end_pfn;
984    struct page *start_page, *end_page;
985
986    start_pfn = page_to_pfn(page);
987    start_pfn = start_pfn & ~(pageblock_nr_pages-1);
988    start_page = pfn_to_page(start_pfn);
989    end_page = start_page + pageblock_nr_pages - 1;
990    end_pfn = start_pfn + pageblock_nr_pages - 1;
991
992    /* Do not cross zone boundaries */
993    if (!zone_spans_pfn(zone, start_pfn))
994        start_page = page;
995    if (!zone_spans_pfn(zone, end_pfn))
996        return 0;
997
998    return move_freepages(zone, start_page, end_page, migratetype);
999}
1000
1001static void change_pageblock_range(struct page *pageblock_page,
1002                    int start_order, int migratetype)
1003{
1004    int nr_pageblocks = 1 << (start_order - pageblock_order);
1005
1006    while (nr_pageblocks--) {
1007        set_pageblock_migratetype(pageblock_page, migratetype);
1008        pageblock_page += pageblock_nr_pages;
1009    }
1010}
1011
1012/* Remove an element from the buddy allocator from the fallback list */
1013static inline struct page *
1014__rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
1015{
1016    struct free_area * area;
1017    int current_order;
1018    struct page *page;
1019    int migratetype, i;
1020
1021    /* Find the largest possible block of pages in the other list */
1022    for (current_order = MAX_ORDER-1; current_order >= order;
1023                        --current_order) {
1024        for (i = 0;; i++) {
1025            migratetype = fallbacks[start_migratetype][i];
1026
1027            /* MIGRATE_RESERVE handled later if necessary */
1028            if (migratetype == MIGRATE_RESERVE)
1029                break;
1030
1031            area = &(zone->free_area[current_order]);
1032            if (list_empty(&area->free_list[migratetype]))
1033                continue;
1034
1035            page = list_entry(area->free_list[migratetype].next,
1036                    struct page, lru);
1037            area->nr_free--;
1038
1039            /*
1040             * If breaking a large block of pages, move all free
1041             * pages to the preferred allocation list. If falling
1042             * back for a reclaimable kernel allocation, be more
1043             * aggressive about taking ownership of free pages
1044             *
1045             * On the other hand, never change migration
1046             * type of MIGRATE_CMA pageblocks nor move CMA
1047             * pages on different free lists. We don't
1048             * want unmovable pages to be allocated from
1049             * MIGRATE_CMA areas.
1050             */
1051            if (!is_migrate_cma(migratetype) &&
1052                (unlikely(current_order >= pageblock_order / 2) ||
1053                 start_migratetype == MIGRATE_RECLAIMABLE ||
1054                 page_group_by_mobility_disabled)) {
1055                int pages;
1056                pages = move_freepages_block(zone, page,
1057                                start_migratetype);
1058
1059                /* Claim the whole block if over half of it is free */
1060                if (pages >= (1 << (pageblock_order-1)) ||
1061                        page_group_by_mobility_disabled)
1062                    set_pageblock_migratetype(page,
1063                                start_migratetype);
1064
1065                migratetype = start_migratetype;
1066            }
1067
1068            /* Remove the page from the freelists */
1069            list_del(&page->lru);
1070            rmv_page_order(page);
1071
1072            /* Take ownership for orders >= pageblock_order */
1073            if (current_order >= pageblock_order &&
1074                !is_migrate_cma(migratetype))
1075                change_pageblock_range(page, current_order,
1076                            start_migratetype);
1077
1078            expand(zone, page, order, current_order, area,
1079                   is_migrate_cma(migratetype)
1080                 ? migratetype : start_migratetype);
1081
1082            trace_mm_page_alloc_extfrag(page, order, current_order,
1083                start_migratetype, migratetype);
1084
1085            return page;
1086        }
1087    }
1088
1089    return NULL;
1090}
1091
1092/*
1093 * Do the hard work of removing an element from the buddy allocator.
1094 * Call me with the zone->lock already held.
1095 */
1096static struct page *__rmqueue(struct zone *zone, unsigned int order,
1097                        int migratetype)
1098{
1099    struct page *page;
1100
1101retry_reserve:
1102    page = __rmqueue_smallest(zone, order, migratetype);
1103
1104    if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
1105        page = __rmqueue_fallback(zone, order, migratetype);
1106
1107        /*
1108         * Use MIGRATE_RESERVE rather than fail an allocation. goto
1109         * is used because __rmqueue_smallest is an inline function
1110         * and we want just one call site
1111         */
1112        if (!page) {
1113            migratetype = MIGRATE_RESERVE;
1114            goto retry_reserve;
1115        }
1116    }
1117
1118    trace_mm_page_alloc_zone_locked(page, order, migratetype);
1119    return page;
1120}
1121
1122/*
1123 * Obtain a specified number of elements from the buddy allocator, all under
1124 * a single hold of the lock, for efficiency. Add them to the supplied list.
1125 * Returns the number of new pages which were placed at *list.
1126 */
1127static int rmqueue_bulk(struct zone *zone, unsigned int order,
1128            unsigned long count, struct list_head *list,
1129            int migratetype, int cold)
1130{
1131    int mt = migratetype, i;
1132
1133    spin_lock(&zone->lock);
1134    for (i = 0; i < count; ++i) {
1135        struct page *page = __rmqueue(zone, order, migratetype);
1136        if (unlikely(page == NULL))
1137            break;
1138
1139        /*
1140         * Split buddy pages returned by expand() are received here
1141         * in physical page order. The page is added to the callers and
1142         * list and the list head then moves forward. From the callers
1143         * perspective, the linked list is ordered by page number in
1144         * some conditions. This is useful for IO devices that can
1145         * merge IO requests if the physical pages are ordered
1146         * properly.
1147         */
1148        if (likely(cold == 0))
1149            list_add(&page->lru, list);
1150        else
1151            list_add_tail(&page->lru, list);
1152        if (IS_ENABLED(CONFIG_CMA)) {
1153            mt = get_pageblock_migratetype(page);
1154            if (!is_migrate_cma(mt) && !is_migrate_isolate(mt))
1155                mt = migratetype;
1156        }
1157        set_freepage_migratetype(page, mt);
1158        list = &page->lru;
1159        if (is_migrate_cma(mt))
1160            __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
1161                          -(1 << order));
1162    }
1163    __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
1164    spin_unlock(&zone->lock);
1165    return i;
1166}
1167
1168#ifdef CONFIG_NUMA
1169/*
1170 * Called from the vmstat counter updater to drain pagesets of this
1171 * currently executing processor on remote nodes after they have
1172 * expired.
1173 *
1174 * Note that this function must be called with the thread pinned to
1175 * a single processor.
1176 */
1177void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
1178{
1179    unsigned long flags;
1180    int to_drain;
1181
1182    local_irq_save(flags);
1183    if (pcp->count >= pcp->batch)
1184        to_drain = pcp->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        free_pcppages_bulk(zone, pcp->batch, pcp);
1353        pcp->count -= pcp->batch;
1354    }
1355
1356out:
1357    local_irq_restore(flags);
1358}
1359
1360/*
1361 * Free a list of 0-order pages
1362 */
1363void free_hot_cold_page_list(struct list_head *list, int cold)
1364{
1365    struct page *page, *next;
1366
1367    list_for_each_entry_safe(page, next, list, lru) {
1368        trace_mm_page_free_batched(page, cold);
1369        free_hot_cold_page(page, cold);
1370    }
1371}
1372
1373/*
1374 * split_page takes a non-compound higher-order page, and splits it into
1375 * n (1<<order) sub-pages: page[0..n]
1376 * Each sub-page must be freed individually.
1377 *
1378 * Note: this is probably too low level an operation for use in drivers.
1379 * Please consult with lkml before using this in your driver.
1380 */
1381void split_page(struct page *page, unsigned int order)
1382{
1383    int i;
1384
1385    VM_BUG_ON(PageCompound(page));
1386    VM_BUG_ON(!page_count(page));
1387
1388#ifdef CONFIG_KMEMCHECK
1389    /*
1390     * Split shadow pages too, because free(page[0]) would
1391     * otherwise free the whole shadow.
1392     */
1393    if (kmemcheck_page_is_tracked(page))
1394        split_page(virt_to_page(page[0].shadow), order);
1395#endif
1396
1397    for (i = 1; i < (1 << order); i++)
1398        set_page_refcounted(page + i);
1399}
1400
1401static int __isolate_free_page(struct page *page, unsigned int order)
1402{
1403    unsigned long watermark;
1404    struct zone *zone;
1405    int mt;
1406
1407    BUG_ON(!PageBuddy(page));
1408
1409    zone = page_zone(page);
1410    mt = get_pageblock_migratetype(page);
1411
1412    if (!is_migrate_isolate(mt)) {
1413        /* Obey watermarks as if the page was being allocated */
1414        watermark = low_wmark_pages(zone) + (1 << order);
1415        if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
1416            return 0;
1417
1418        __mod_zone_freepage_state(zone, -(1UL << order), mt);
1419    }
1420
1421    /* Remove page from free list */
1422    list_del(&page->lru);
1423    zone->free_area[order].nr_free--;
1424    rmv_page_order(page);
1425
1426    /* Set the pageblock if the isolated page is at least a pageblock */
1427    if (order >= pageblock_order - 1) {
1428        struct page *endpage = page + (1 << order) - 1;
1429        for (; page < endpage; page += pageblock_nr_pages) {
1430            int mt = get_pageblock_migratetype(page);
1431            if (!is_migrate_isolate(mt) && !is_migrate_cma(mt))
1432                set_pageblock_migratetype(page,
1433                              MIGRATE_MOVABLE);
1434        }
1435    }
1436
1437    return 1UL << order;
1438}
1439
1440/*
1441 * Similar to split_page except the page is already free. As this is only
1442 * being used for migration, the migratetype of the block also changes.
1443 * As this is called with interrupts disabled, the caller is responsible
1444 * for calling arch_alloc_page() and kernel_map_page() after interrupts
1445 * are enabled.
1446 *
1447 * Note: this is probably too low level an operation for use in drivers.
1448 * Please consult with lkml before using this in your driver.
1449 */
1450int split_free_page(struct page *page)
1451{
1452    unsigned int order;
1453    int nr_pages;
1454
1455    order = page_order(page);
1456
1457    nr_pages = __isolate_free_page(page, order);
1458    if (!nr_pages)
1459        return 0;
1460
1461    /* Split into individual pages */
1462    set_page_refcounted(page);
1463    split_page(page, order);
1464    return nr_pages;
1465}
1466
1467/*
1468 * Really, prep_compound_page() should be called from __rmqueue_bulk(). But
1469 * we cheat by calling it from here, in the order > 0 path. Saves a branch
1470 * or two.
1471 */
1472static inline
1473struct page *buffered_rmqueue(struct zone *preferred_zone,
1474            struct zone *zone, int order, gfp_t gfp_flags,
1475            int migratetype)
1476{
1477    unsigned long flags;
1478    struct page *page;
1479    int cold = !!(gfp_flags & __GFP_COLD);
1480
1481again:
1482    if (likely(order == 0)) {
1483        struct per_cpu_pages *pcp;
1484        struct list_head *list;
1485
1486        local_irq_save(flags);
1487        pcp = &this_cpu_ptr(zone->pageset)->pcp;
1488        list = &pcp->lists[migratetype];
1489        if (list_empty(list)) {
1490            pcp->count += rmqueue_bulk(zone, 0,
1491                    pcp->batch, list,
1492                    migratetype, cold);
1493            if (unlikely(list_empty(list)))
1494                goto failed;
1495        }
1496
1497        if (cold)
1498            page = list_entry(list->prev, struct page, lru);
1499        else
1500            page = list_entry(list->next, struct page, lru);
1501
1502        list_del(&page->lru);
1503        pcp->count--;
1504    } else {
1505        if (unlikely(gfp_flags & __GFP_NOFAIL)) {
1506            /*
1507             * __GFP_NOFAIL is not to be used in new code.
1508             *
1509             * All __GFP_NOFAIL callers should be fixed so that they
1510             * properly detect and handle allocation failures.
1511             *
1512             * We most definitely don't want callers attempting to
1513             * allocate greater than order-1 page units with
1514             * __GFP_NOFAIL.
1515             */
1516            WARN_ON_ONCE(order > 1);
1517        }
1518        spin_lock_irqsave(&zone->lock, flags);
1519        page = __rmqueue(zone, order, migratetype);
1520        spin_unlock(&zone->lock);
1521        if (!page)
1522            goto failed;
1523        __mod_zone_freepage_state(zone, -(1 << order),
1524                      get_pageblock_migratetype(page));
1525    }
1526
1527    __count_zone_vm_events(PGALLOC, zone, 1 << order);
1528    zone_statistics(preferred_zone, zone, gfp_flags);
1529    local_irq_restore(flags);
1530
1531    VM_BUG_ON(bad_range(zone, page));
1532    if (prep_new_page(page, order, gfp_flags))
1533        goto again;
1534    return page;
1535
1536failed:
1537    local_irq_restore(flags);
1538    return NULL;
1539}
1540
1541#ifdef CONFIG_FAIL_PAGE_ALLOC
1542
1543static struct {
1544    struct fault_attr attr;
1545
1546    u32 ignore_gfp_highmem;
1547    u32 ignore_gfp_wait;
1548    u32 min_order;
1549} fail_page_alloc = {
1550    .attr = FAULT_ATTR_INITIALIZER,
1551    .ignore_gfp_wait = 1,
1552    .ignore_gfp_highmem = 1,
1553    .min_order = 1,
1554};
1555
1556static int __init setup_fail_page_alloc(char *str)
1557{
1558    return setup_fault_attr(&fail_page_alloc.attr, str);
1559}
1560__setup("fail_page_alloc=", setup_fail_page_alloc);
1561
1562static bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1563{
1564    if (order < fail_page_alloc.min_order)
1565        return false;
1566    if (gfp_mask & __GFP_NOFAIL)
1567        return false;
1568    if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1569        return false;
1570    if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1571        return false;
1572
1573    return should_fail(&fail_page_alloc.attr, 1 << order);
1574}
1575
1576#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1577
1578static int __init fail_page_alloc_debugfs(void)
1579{
1580    umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1581    struct dentry *dir;
1582
1583    dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
1584                    &fail_page_alloc.attr);
1585    if (IS_ERR(dir))
1586        return PTR_ERR(dir);
1587
1588    if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
1589                &fail_page_alloc.ignore_gfp_wait))
1590        goto fail;
1591    if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1592                &fail_page_alloc.ignore_gfp_highmem))
1593        goto fail;
1594    if (!debugfs_create_u32("min-order", mode, dir,
1595                &fail_page_alloc.min_order))
1596        goto fail;
1597
1598    return 0;
1599fail:
1600    debugfs_remove_recursive(dir);
1601
1602    return -ENOMEM;
1603}
1604
1605late_initcall(fail_page_alloc_debugfs);
1606
1607#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1608
1609#else /* CONFIG_FAIL_PAGE_ALLOC */
1610
1611static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1612{
1613    return false;
1614}
1615
1616#endif /* CONFIG_FAIL_PAGE_ALLOC */
1617
1618/*
1619 * Return true if free pages are above 'mark'. This takes into account the order
1620 * of the allocation.
1621 */
1622static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1623              int classzone_idx, int alloc_flags, long free_pages)
1624{
1625    /* free_pages my go negative - that's OK */
1626    long min = mark;
1627    long lowmem_reserve = z->lowmem_reserve[classzone_idx];
1628    int o;
1629
1630    free_pages -= (1 << order) - 1;
1631    if (alloc_flags & ALLOC_HIGH)
1632        min -= min / 2;
1633    if (alloc_flags & ALLOC_HARDER)
1634        min -= min / 4;
1635#ifdef CONFIG_CMA
1636    /* If allocation can't use CMA areas don't use free CMA pages */
1637    if (!(alloc_flags & ALLOC_CMA))
1638        free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
1639#endif
1640    if (free_pages <= min + lowmem_reserve)
1641        return false;
1642    for (o = 0; o < order; o++) {
1643        /* At the next order, this order's pages become unavailable */
1644        free_pages -= z->free_area[o].nr_free << o;
1645
1646        /* Require fewer higher order pages to be free */
1647        min >>= 1;
1648
1649        if (free_pages <= min)
1650            return false;
1651    }
1652    return true;
1653}
1654
1655bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1656              int classzone_idx, int alloc_flags)
1657{
1658    return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1659                    zone_page_state(z, NR_FREE_PAGES));
1660}
1661
1662bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark,
1663              int classzone_idx, int alloc_flags)
1664{
1665    long free_pages = zone_page_state(z, NR_FREE_PAGES);
1666
1667    if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
1668        free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
1669
1670    return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1671                                free_pages);
1672}
1673
1674#ifdef CONFIG_NUMA
1675/*
1676 * zlc_setup - Setup for "zonelist cache". Uses cached zone data to
1677 * skip over zones that are not allowed by the cpuset, or that have
1678 * been recently (in last second) found to be nearly full. See further
1679 * comments in mmzone.h. Reduces cache footprint of zonelist scans
1680 * that have to skip over a lot of full or unallowed zones.
1681 *
1682 * If the zonelist cache is present in the passed in zonelist, then
1683 * returns a pointer to the allowed node mask (either the current
1684 * tasks mems_allowed, or node_states[N_MEMORY].)
1685 *
1686 * If the zonelist cache is not available for this zonelist, does
1687 * nothing and returns NULL.
1688 *
1689 * If the fullzones BITMAP in the zonelist cache is stale (more than
1690 * a second since last zap'd) then we zap it out (clear its bits.)
1691 *
1692 * We hold off even calling zlc_setup, until after we've checked the
1693 * first zone in the zonelist, on the theory that most allocations will
1694 * be satisfied from that first zone, so best to examine that zone as
1695 * quickly as we can.
1696 */
1697static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1698{
1699    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1700    nodemask_t *allowednodes; /* zonelist_cache approximation */
1701
1702    zlc = zonelist->zlcache_ptr;
1703    if (!zlc)
1704        return NULL;
1705
1706    if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1707        bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1708        zlc->last_full_zap = jiffies;
1709    }
1710
1711    allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1712                    &cpuset_current_mems_allowed :
1713                    &node_states[N_MEMORY];
1714    return allowednodes;
1715}
1716
1717/*
1718 * Given 'z' scanning a zonelist, run a couple of quick checks to see
1719 * if it is worth looking at further for free memory:
1720 * 1) Check that the zone isn't thought to be full (doesn't have its
1721 * bit set in the zonelist_cache fullzones BITMAP).
1722 * 2) Check that the zones node (obtained from the zonelist_cache
1723 * z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1724 * Return true (non-zero) if zone is worth looking at further, or
1725 * else return false (zero) if it is not.
1726 *
1727 * This check -ignores- the distinction between various watermarks,
1728 * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ... If a zone is
1729 * found to be full for any variation of these watermarks, it will
1730 * be considered full for up to one second by all requests, unless
1731 * we are so low on memory on all allowed nodes that we are forced
1732 * into the second scan of the zonelist.
1733 *
1734 * In the second scan we ignore this zonelist cache and exactly
1735 * apply the watermarks to all zones, even it is slower to do so.
1736 * We are low on memory in the second scan, and should leave no stone
1737 * unturned looking for a free page.
1738 */
1739static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1740                        nodemask_t *allowednodes)
1741{
1742    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1743    int i; /* index of *z in zonelist zones */
1744    int n; /* node that zone *z is on */
1745
1746    zlc = zonelist->zlcache_ptr;
1747    if (!zlc)
1748        return 1;
1749
1750    i = z - zonelist->_zonerefs;
1751    n = zlc->z_to_n[i];
1752
1753    /* This zone is worth trying if it is allowed but not full */
1754    return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1755}
1756
1757/*
1758 * Given 'z' scanning a zonelist, set the corresponding bit in
1759 * zlc->fullzones, so that subsequent attempts to allocate a page
1760 * from that zone don't waste time re-examining it.
1761 */
1762static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1763{
1764    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1765    int i; /* index of *z in zonelist zones */
1766
1767    zlc = zonelist->zlcache_ptr;
1768    if (!zlc)
1769        return;
1770
1771    i = z - zonelist->_zonerefs;
1772
1773    set_bit(i, zlc->fullzones);
1774}
1775
1776/*
1777 * clear all zones full, called after direct reclaim makes progress so that
1778 * a zone that was recently full is not skipped over for up to a second
1779 */
1780static void zlc_clear_zones_full(struct zonelist *zonelist)
1781{
1782    struct zonelist_cache *zlc; /* cached zonelist speedup info */
1783
1784    zlc = zonelist->zlcache_ptr;
1785    if (!zlc)
1786        return;
1787
1788    bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1789}
1790
1791static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
1792{
1793    return node_isset(local_zone->node, zone->zone_pgdat->reclaim_nodes);
1794}
1795
1796static void __paginginit init_zone_allows_reclaim(int nid)
1797{
1798    int i;
1799
1800    for_each_online_node(i)
1801        if (node_distance(nid, i) <= RECLAIM_DISTANCE)
1802            node_set(i, NODE_DATA(nid)->reclaim_nodes);
1803        else
1804            zone_reclaim_mode = 1;
1805}
1806
1807#else /* CONFIG_NUMA */
1808
1809static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1810{
1811    return NULL;
1812}
1813
1814static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1815                nodemask_t *allowednodes)
1816{
1817    return 1;
1818}
1819
1820static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1821{
1822}
1823
1824static void zlc_clear_zones_full(struct zonelist *zonelist)
1825{
1826}
1827
1828static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
1829{
1830    return true;
1831}
1832
1833static inline void init_zone_allows_reclaim(int nid)
1834{
1835}
1836#endif /* CONFIG_NUMA */
1837
1838/*
1839 * get_page_from_freelist goes through the zonelist trying to allocate
1840 * a page.
1841 */
1842static struct page *
1843get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1844        struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
1845        struct zone *preferred_zone, int migratetype)
1846{
1847    struct zoneref *z;
1848    struct page *page = NULL;
1849    int classzone_idx;
1850    struct zone *zone;
1851    nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1852    int zlc_active = 0; /* set if using zonelist_cache */
1853    int did_zlc_setup = 0; /* just call zlc_setup() one time */
1854
1855    classzone_idx = zone_idx(preferred_zone);
1856zonelist_scan:
1857    /*
1858     * Scan zonelist, looking for a zone with enough free.
1859     * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1860     */
1861    for_each_zone_zonelist_nodemask(zone, z, zonelist,
1862                        high_zoneidx, nodemask) {
1863        if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
1864            !zlc_zone_worth_trying(zonelist, z, allowednodes))
1865                continue;
1866        if ((alloc_flags & ALLOC_CPUSET) &&
1867            !cpuset_zone_allowed_softwall(zone, gfp_mask))
1868                continue;
1869        /*
1870         * When allocating a page cache page for writing, we
1871         * want to get it from a zone that is within its dirty
1872         * limit, such that no single zone holds more than its
1873         * proportional share of globally allowed dirty pages.
1874         * The dirty limits take into account the zone's
1875         * lowmem reserves and high watermark so that kswapd
1876         * should be able to balance it without having to
1877         * write pages from its LRU list.
1878         *
1879         * This may look like it could increase pressure on
1880         * lower zones by failing allocations in higher zones
1881         * before they are full. But the pages that do spill
1882         * over are limited as the lower zones are protected
1883         * by this very same mechanism. It should not become
1884         * a practical burden to them.
1885         *
1886         * XXX: For now, allow allocations to potentially
1887         * exceed the per-zone dirty limit in the slowpath
1888         * (ALLOC_WMARK_LOW unset) before going into reclaim,
1889         * which is important when on a NUMA setup the allowed
1890         * zones are together not big enough to reach the
1891         * global limit. The proper fix for these situations
1892         * will require awareness of zones in the
1893         * dirty-throttling and the flusher threads.
1894         */
1895        if ((alloc_flags & ALLOC_WMARK_LOW) &&
1896            (gfp_mask & __GFP_WRITE) && !zone_dirty_ok(zone))
1897            goto this_zone_full;
1898
1899        BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
1900        if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
1901            unsigned long mark;
1902            int ret;
1903
1904            mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
1905            if (zone_watermark_ok(zone, order, mark,
1906                    classzone_idx, alloc_flags))
1907                goto try_this_zone;
1908
1909            if (IS_ENABLED(CONFIG_NUMA) &&
1910                    !did_zlc_setup && nr_online_nodes > 1) {
1911                /*
1912                 * we do zlc_setup if there are multiple nodes
1913                 * and before considering the first zone allowed
1914                 * by the cpuset.
1915                 */
1916                allowednodes = zlc_setup(zonelist, alloc_flags);
1917                zlc_active = 1;
1918                did_zlc_setup = 1;
1919            }
1920
1921            if (zone_reclaim_mode == 0 ||
1922                !zone_allows_reclaim(preferred_zone, zone))
1923                goto this_zone_full;
1924
1925            /*
1926             * As we may have just activated ZLC, check if the first
1927             * eligible zone has failed zone_reclaim recently.
1928             */
1929            if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
1930                !zlc_zone_worth_trying(zonelist, z, allowednodes))
1931                continue;
1932
1933            ret = zone_reclaim(zone, gfp_mask, order);
1934            switch (ret) {
1935            case ZONE_RECLAIM_NOSCAN:
1936                /* did not scan */
1937                continue;
1938            case ZONE_RECLAIM_FULL:
1939                /* scanned but unreclaimable */
1940                continue;
1941            default:
1942                /* did we reclaim enough */
1943                if (!zone_watermark_ok(zone, order, mark,
1944                        classzone_idx, alloc_flags))
1945                    goto this_zone_full;
1946            }
1947        }
1948
1949try_this_zone:
1950        page = buffered_rmqueue(preferred_zone, zone, order,
1951                        gfp_mask, migratetype);
1952        if (page)
1953            break;
1954this_zone_full:
1955        if (IS_ENABLED(CONFIG_NUMA))
1956            zlc_mark_zone_full(zonelist, z);
1957    }
1958
1959    if (unlikely(IS_ENABLED(CONFIG_NUMA) && page == NULL && zlc_active)) {
1960        /* Disable zlc cache for second zonelist scan */
1961        zlc_active = 0;
1962        goto zonelist_scan;
1963    }
1964
1965    if (page)
1966        /*
1967         * page->pfmemalloc is set when ALLOC_NO_WATERMARKS was
1968         * necessary to allocate the page. The expectation is
1969         * that the caller is taking steps that will free more
1970         * memory. The caller should avoid the page being used
1971         * for !PFMEMALLOC purposes.
1972         */
1973        page->pfmemalloc = !!(alloc_flags & ALLOC_NO_WATERMARKS);
1974
1975    return page;
1976}
1977
1978/*
1979 * Large machines with many possible nodes should not always dump per-node
1980 * meminfo in irq context.
1981 */
1982static inline bool should_suppress_show_mem(void)
1983{
1984    bool ret = false;
1985
1986#if NODES_SHIFT > 8
1987    ret = in_interrupt();
1988#endif
1989    return ret;
1990}
1991
1992static DEFINE_RATELIMIT_STATE(nopage_rs,
1993        DEFAULT_RATELIMIT_INTERVAL,
1994        DEFAULT_RATELIMIT_BURST);
1995
1996void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...)
1997{
1998    unsigned int filter = SHOW_MEM_FILTER_NODES;
1999
2000    if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) ||
2001        debug_guardpage_minorder() > 0)
2002        return;
2003
2004    /*
2005     * This documents exceptions given to allocations in certain
2006     * contexts that are allowed to allocate outside current's set
2007     * of allowed nodes.
2008     */
2009    if (!(gfp_mask & __GFP_NOMEMALLOC))
2010        if (test_thread_flag(TIF_MEMDIE) ||
2011            (current->flags & (PF_MEMALLOC | PF_EXITING)))
2012            filter &= ~SHOW_MEM_FILTER_NODES;
2013    if (in_interrupt() || !(gfp_mask & __GFP_WAIT))
2014        filter &= ~SHOW_MEM_FILTER_NODES;
2015
2016    if (fmt) {
2017        struct va_format vaf;
2018        va_list args;
2019
2020        va_start(args, fmt);
2021
2022        vaf.fmt = fmt;
2023        vaf.va = &args;
2024
2025        pr_warn("%pV", &vaf);
2026
2027        va_end(args);
2028    }
2029
2030    pr_warn("%s: page allocation failure: order:%d, mode:0x%x\n",
2031        current->comm, order, gfp_mask);
2032
2033    dump_stack();
2034    if (!should_suppress_show_mem())
2035        show_mem(filter);
2036}
2037
2038static inline int
2039should_alloc_retry(gfp_t gfp_mask, unsigned int order,
2040                unsigned long did_some_progress,
2041                unsigned long pages_reclaimed)
2042{
2043    /* Do not loop if specifically requested */
2044    if (gfp_mask & __GFP_NORETRY)
2045        return 0;
2046
2047    /* Always retry if specifically requested */
2048    if (gfp_mask & __GFP_NOFAIL)
2049        return 1;
2050
2051    /*
2052     * Suspend converts GFP_KERNEL to __GFP_WAIT which can prevent reclaim
2053     * making forward progress without invoking OOM. Suspend also disables
2054     * storage devices so kswapd will not help. Bail if we are suspending.
2055     */
2056    if (!did_some_progress && pm_suspended_storage())
2057        return 0;
2058
2059    /*
2060     * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
2061     * means __GFP_NOFAIL, but that may not be true in other
2062     * implementations.
2063     */
2064    if (order <= PAGE_ALLOC_COSTLY_ORDER)
2065        return 1;
2066
2067    /*
2068     * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
2069     * specified, then we retry until we no longer reclaim any pages
2070     * (above), or we've reclaimed an order of pages at least as
2071     * large as the allocation's order. In both cases, if the
2072     * allocation still fails, we stop retrying.
2073     */
2074    if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
2075        return 1;
2076
2077    return 0;
2078}
2079
2080static inline struct page *
2081__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
2082    struct zonelist *zonelist, enum zone_type high_zoneidx,
2083    nodemask_t *nodemask, struct zone *preferred_zone,
2084    int migratetype)
2085{
2086    struct page *page;
2087
2088    /* Acquire the OOM killer lock for the zones in zonelist */
2089    if (!try_set_zonelist_oom(zonelist, gfp_mask)) {
2090        schedule_timeout_uninterruptible(1);
2091        return NULL;
2092    }
2093
2094    /*
2095     * Go through the zonelist yet one more time, keep very high watermark
2096     * here, this is only to catch a parallel oom killing, we must fail if
2097     * we're still under heavy pressure.
2098     */
2099    page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
2100        order, zonelist, high_zoneidx,
2101        ALLOC_WMARK_HIGH|ALLOC_CPUSET,
2102        preferred_zone, migratetype);
2103    if (page)
2104        goto out;
2105
2106    if (!(gfp_mask & __GFP_NOFAIL)) {
2107        /* The OOM killer will not help higher order allocs */
2108        if (order > PAGE_ALLOC_COSTLY_ORDER)
2109            goto out;
2110        /* The OOM killer does not needlessly kill tasks for lowmem */
2111        if (high_zoneidx < ZONE_NORMAL)
2112            goto out;
2113        /*
2114         * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
2115         * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
2116         * The caller should handle page allocation failure by itself if
2117         * it specifies __GFP_THISNODE.
2118         * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
2119         */
2120        if (gfp_mask & __GFP_THISNODE)
2121            goto out;
2122    }
2123    /* Exhausted what can be done so it's blamo time */
2124    out_of_memory(zonelist, gfp_mask, order, nodemask, false);
2125
2126out:
2127    clear_zonelist_oom(zonelist, gfp_mask);
2128    return page;
2129}
2130
2131#ifdef CONFIG_COMPACTION
2132/* Try memory compaction for high-order allocations before reclaim */
2133static struct page *
2134__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2135    struct zonelist *zonelist, enum zone_type high_zoneidx,
2136    nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2137    int migratetype, bool sync_migration,
2138    bool *contended_compaction, bool *deferred_compaction,
2139    unsigned long *did_some_progress)
2140{
2141    if (!order)
2142        return NULL;
2143
2144    if (compaction_deferred(preferred_zone, order)) {
2145        *deferred_compaction = true;
2146        return NULL;
2147    }
2148
2149    current->flags |= PF_MEMALLOC;
2150    *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
2151                        nodemask, sync_migration,
2152                        contended_compaction);
2153    current->flags &= ~PF_MEMALLOC;
2154
2155    if (*did_some_progress != COMPACT_SKIPPED) {
2156        struct page *page;
2157
2158        /* Page migration frees to the PCP lists but we want merging */
2159        drain_pages(get_cpu());
2160        put_cpu();
2161
2162        page = get_page_from_freelist(gfp_mask, nodemask,
2163                order, zonelist, high_zoneidx,
2164                alloc_flags & ~ALLOC_NO_WATERMARKS,
2165                preferred_zone, migratetype);
2166        if (page) {
2167            preferred_zone->compact_blockskip_flush = false;
2168            preferred_zone->compact_considered = 0;
2169            preferred_zone->compact_defer_shift = 0;
2170            if (order >= preferred_zone->compact_order_failed)
2171                preferred_zone->compact_order_failed = order + 1;
2172            count_vm_event(COMPACTSUCCESS);
2173            return page;
2174        }
2175
2176        /*
2177         * It's bad if compaction run occurs and fails.
2178         * The most likely reason is that pages exist,
2179         * but not enough to satisfy watermarks.
2180         */
2181        count_vm_event(COMPACTFAIL);
2182
2183        /*
2184         * As async compaction considers a subset of pageblocks, only
2185         * defer if the failure was a sync compaction failure.
2186         */
2187        if (sync_migration)
2188            defer_compaction(preferred_zone, order);
2189
2190        cond_resched();
2191    }
2192
2193    return NULL;
2194}
2195#else
2196static inline struct page *
2197__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2198    struct zonelist *zonelist, enum zone_type high_zoneidx,
2199    nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2200    int migratetype, bool sync_migration,
2201    bool *contended_compaction, bool *deferred_compaction,
2202    unsigned long *did_some_progress)
2203{
2204    return NULL;
2205}
2206#endif /* CONFIG_COMPACTION */
2207
2208/* Perform direct synchronous page reclaim */
2209static int
2210__perform_reclaim(gfp_t gfp_mask, unsigned int order, struct zonelist *zonelist,
2211          nodemask_t *nodemask)
2212{
2213    struct reclaim_state reclaim_state;
2214    int progress;
2215
2216    cond_resched();
2217
2218    /* We now go into synchronous reclaim */
2219    cpuset_memory_pressure_bump();
2220    current->flags |= PF_MEMALLOC;
2221    lockdep_set_current_reclaim_state(gfp_mask);
2222    reclaim_state.reclaimed_slab = 0;
2223    current->reclaim_state = &reclaim_state;
2224
2225    progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
2226
2227    current->reclaim_state = NULL;
2228    lockdep_clear_current_reclaim_state();
2229    current->flags &= ~PF_MEMALLOC;
2230
2231    cond_resched();
2232
2233    return progress;
2234}
2235
2236/* The really slow allocator path where we enter direct reclaim */
2237static inline struct page *
2238__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
2239    struct zonelist *zonelist, enum zone_type high_zoneidx,
2240    nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2241    int migratetype, unsigned long *did_some_progress)
2242{
2243    struct page *page = NULL;
2244    bool drained = false;
2245
2246    *did_some_progress = __perform_reclaim(gfp_mask, order, zonelist,
2247                           nodemask);
2248    if (unlikely(!(*did_some_progress)))
2249        return NULL;
2250
2251    /* After successful reclaim, reconsider all zones for allocation */
2252    if (IS_ENABLED(CONFIG_NUMA))
2253        zlc_clear_zones_full(zonelist);
2254
2255retry:
2256    page = get_page_from_freelist(gfp_mask, nodemask, order,
2257                    zonelist, high_zoneidx,
2258                    alloc_flags & ~ALLOC_NO_WATERMARKS,
2259                    preferred_zone, migratetype);
2260
2261    /*
2262     * If an allocation failed after direct reclaim, it could be because
2263     * pages are pinned on the per-cpu lists. Drain them and try again
2264     */
2265    if (!page && !drained) {
2266        drain_all_pages();
2267        drained = true;
2268        goto retry;
2269    }
2270
2271    return page;
2272}
2273
2274/*
2275 * This is called in the allocator slow-path if the allocation request is of
2276 * sufficient urgency to ignore watermarks and take other desperate measures
2277 */
2278static inline struct page *
2279__alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
2280    struct zonelist *zonelist, enum zone_type high_zoneidx,
2281    nodemask_t *nodemask, struct zone *preferred_zone,
2282    int migratetype)
2283{
2284    struct page *page;
2285
2286    do {
2287        page = get_page_from_freelist(gfp_mask, nodemask, order,
2288            zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
2289            preferred_zone, migratetype);
2290
2291        if (!page && gfp_mask & __GFP_NOFAIL)
2292            wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2293    } while (!page && (gfp_mask & __GFP_NOFAIL));
2294
2295    return page;
2296}
2297
2298static inline
2299void wake_all_kswapd(unsigned int order, struct zonelist *zonelist,
2300                        enum zone_type high_zoneidx,
2301                        enum zone_type classzone_idx)
2302{
2303    struct zoneref *z;
2304    struct zone *zone;
2305
2306    for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
2307        wakeup_kswapd(zone, order, classzone_idx);
2308}
2309
2310static inline int
2311gfp_to_alloc_flags(gfp_t gfp_mask)
2312{
2313    int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
2314    const gfp_t wait = gfp_mask & __GFP_WAIT;
2315
2316    /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
2317    BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
2318
2319    /*
2320     * The caller may dip into page reserves a bit more if the caller
2321     * cannot run direct reclaim, or if the caller has realtime scheduling
2322     * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
2323     * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
2324     */
2325    alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
2326
2327    if (!wait) {
2328        /*
2329         * Not worth trying to allocate harder for
2330         * __GFP_NOMEMALLOC even if it can't schedule.
2331         */
2332        if (!(gfp_mask & __GFP_NOMEMALLOC))
2333            alloc_flags |= ALLOC_HARDER;
2334        /*
2335         * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
2336         * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
2337         */
2338        alloc_flags &= ~ALLOC_CPUSET;
2339    } else if (unlikely(rt_task(current)) && !in_interrupt())
2340        alloc_flags |= ALLOC_HARDER;
2341
2342    if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
2343        if (gfp_mask & __GFP_MEMALLOC)
2344            alloc_flags |= ALLOC_NO_WATERMARKS;
2345        else if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
2346            alloc_flags |= ALLOC_NO_WATERMARKS;
2347        else if (!in_interrupt() &&
2348                ((current->flags & PF_MEMALLOC) ||
2349                 unlikely(test_thread_flag(TIF_MEMDIE))))
2350            alloc_flags |= ALLOC_NO_WATERMARKS;
2351    }
2352#ifdef CONFIG_CMA
2353    if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
2354        alloc_flags |= ALLOC_CMA;
2355#endif
2356    return alloc_flags;
2357}
2358
2359bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
2360{
2361    return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_NO_WATERMARKS);
2362}
2363
2364static inline struct page *
2365__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
2366    struct zonelist *zonelist, enum zone_type high_zoneidx,
2367    nodemask_t *nodemask, struct zone *preferred_zone,
2368    int migratetype)
2369{
2370    const gfp_t wait = gfp_mask & __GFP_WAIT;
2371    struct page *page = NULL;
2372    int alloc_flags;
2373    unsigned long pages_reclaimed = 0;
2374    unsigned long did_some_progress;
2375    bool sync_migration = false;
2376    bool deferred_compaction = false;
2377    bool contended_compaction = false;
2378
2379    /*
2380     * In the slowpath, we sanity check order to avoid ever trying to
2381     * reclaim >= MAX_ORDER areas which will never succeed. Callers may
2382     * be using allocators in order of preference for an area that is
2383     * too large.
2384     */
2385    if (order >= MAX_ORDER) {
2386        WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
2387        return NULL;
2388    }
2389
2390    /*
2391     * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
2392     * __GFP_NOWARN set) should not cause reclaim since the subsystem
2393     * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
2394     * using a larger set of nodes after it has established that the
2395     * allowed per node queues are empty and that nodes are
2396     * over allocated.
2397     */
2398    if (IS_ENABLED(CONFIG_NUMA) &&
2399            (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
2400        goto nopage;
2401
2402restart:
2403    if (!(gfp_mask & __GFP_NO_KSWAPD))
2404        wake_all_kswapd(order, zonelist, high_zoneidx,
2405                        zone_idx(preferred_zone));
2406
2407    /*
2408     * OK, we're below the kswapd watermark and have kicked background
2409     * reclaim. Now things get more complex, so set up alloc_flags according
2410     * to how we want to proceed.
2411     */
2412    alloc_flags = gfp_to_alloc_flags(gfp_mask);
2413
2414    /*
2415     * Find the true preferred zone if the allocation is unconstrained by
2416     * cpusets.
2417     */
2418    if (!(alloc_flags & ALLOC_CPUSET) && !nodemask)
2419        first_zones_zonelist(zonelist, high_zoneidx, NULL,
2420                    &preferred_zone);
2421
2422rebalance:
2423    /* This is the last chance, in general, before the goto nopage. */
2424    page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
2425            high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
2426            preferred_zone, migratetype);
2427    if (page)
2428        goto got_pg;
2429
2430    /* Allocate without watermarks if the context allows */
2431    if (alloc_flags & ALLOC_NO_WATERMARKS) {
2432        /*
2433         * Ignore mempolicies if ALLOC_NO_WATERMARKS on the grounds
2434         * the allocation is high priority and these type of
2435         * allocations are system rather than user orientated
2436         */
2437        zonelist = node_zonelist(numa_node_id(), gfp_mask);
2438
2439        page = __alloc_pages_high_priority(gfp_mask, order,
2440                zonelist, high_zoneidx, nodemask,
2441                preferred_zone, migratetype);
2442        if (page) {
2443            goto got_pg;
2444        }
2445    }
2446
2447    /* Atomic allocations - we can't balance anything */
2448    if (!wait)
2449        goto nopage;
2450
2451    /* Avoid recursion of direct reclaim */
2452    if (current->flags & PF_MEMALLOC)
2453        goto nopage;
2454
2455    /* Avoid allocations with no watermarks from looping endlessly */
2456    if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
2457        goto nopage;
2458
2459    /*
2460     * Try direct compaction. The first pass is asynchronous. Subsequent
2461     * attempts after direct reclaim are synchronous
2462     */
2463    page = __alloc_pages_direct_compact(gfp_mask, order,
2464                    zonelist, high_zoneidx,
2465                    nodemask,
2466                    alloc_flags, preferred_zone,
2467                    migratetype, sync_migration,
2468                    &contended_compaction,
2469                    &deferred_compaction,
2470                    &did_some_progress);
2471    if (page)
2472        goto got_pg;
2473    sync_migration = true;
2474
2475    /*
2476     * If compaction is deferred for high-order allocations, it is because
2477     * sync compaction recently failed. In this is the case and the caller
2478     * requested a movable allocation that does not heavily disrupt the
2479     * system then fail the allocation instead of entering direct reclaim.
2480     */
2481    if ((deferred_compaction || contended_compaction) &&
2482                        (gfp_mask & __GFP_NO_KSWAPD))
2483        goto nopage;
2484
2485    /* Try direct reclaim and then allocating */
2486    page = __alloc_pages_direct_reclaim(gfp_mask, order,
2487                    zonelist, high_zoneidx,
2488                    nodemask,
2489                    alloc_flags, preferred_zone,
2490                    migratetype, &did_some_progress);
2491    if (page)
2492        goto got_pg;
2493
2494    /*
2495     * If we failed to make any progress reclaiming, then we are
2496     * running out of options and have to consider going OOM
2497     */
2498    if (!did_some_progress) {
2499        if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
2500            if (oom_killer_disabled)
2501                goto nopage;
2502            /* Coredumps can quickly deplete all memory reserves */
2503            if ((current->flags & PF_DUMPCORE) &&
2504                !(gfp_mask & __GFP_NOFAIL))
2505                goto nopage;
2506            page = __alloc_pages_may_oom(gfp_mask, order,
2507                    zonelist, high_zoneidx,
2508                    nodemask, preferred_zone,
2509                    migratetype);
2510            if (page)
2511                goto got_pg;
2512
2513            if (!(gfp_mask & __GFP_NOFAIL)) {
2514                /*
2515                 * The oom killer is not called for high-order
2516                 * allocations that may fail, so if no progress
2517                 * is being made, there are no other options and
2518                 * retrying is unlikely to help.
2519                 */
2520                if (order > PAGE_ALLOC_COSTLY_ORDER)
2521                    goto nopage;
2522                /*
2523                 * The oom killer is not called for lowmem
2524                 * allocations to prevent needlessly killing
2525                 * innocent tasks.
2526                 */
2527                if (high_zoneidx < ZONE_NORMAL)
2528                    goto nopage;
2529            }
2530
2531            goto restart;
2532        }
2533    }
2534
2535    /* Check if we should retry the allocation */
2536    pages_reclaimed += did_some_progress;
2537    if (should_alloc_retry(gfp_mask, order, did_some_progress,
2538                        pages_reclaimed)) {
2539        /* Wait for some write requests to complete then retry */
2540        wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2541        goto rebalance;
2542    } else {
2543        /*
2544         * High-order allocations do not necessarily loop after
2545         * direct reclaim and reclaim/compaction depends on compaction
2546         * being called after reclaim so call directly if necessary
2547         */
2548        page = __alloc_pages_direct_compact(gfp_mask, order,
2549                    zonelist, high_zoneidx,
2550                    nodemask,
2551                    alloc_flags, preferred_zone,
2552                    migratetype, sync_migration,
2553                    &contended_compaction,
2554                    &deferred_compaction,
2555                    &did_some_progress);
2556        if (page)
2557            goto got_pg;
2558    }
2559
2560nopage:
2561    warn_alloc_failed(gfp_mask, order, NULL);
2562    return page;
2563got_pg:
2564    if (kmemcheck_enabled)
2565        kmemcheck_pagealloc_alloc(page, order, gfp_mask);
2566
2567    return page;
2568}
2569
2570/*
2571 * This is the 'heart' of the zoned buddy allocator.
2572 */
2573struct page *
2574__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
2575            struct zonelist *zonelist, nodemask_t *nodemask)
2576{
2577    enum zone_type high_zoneidx = gfp_zone(gfp_mask);
2578    struct zone *preferred_zone;
2579    struct page *page = NULL;
2580    int migratetype = allocflags_to_migratetype(gfp_mask);
2581    unsigned int cpuset_mems_cookie;
2582    int alloc_flags = ALLOC_WMARK_LOW|ALLOC_CPUSET;
2583    struct mem_cgroup *memcg = NULL;
2584
2585    gfp_mask &= gfp_allowed_mask;
2586
2587    lockdep_trace_alloc(gfp_mask);
2588
2589    might_sleep_if(gfp_mask & __GFP_WAIT);
2590
2591    if (should_fail_alloc_page(gfp_mask, order))
2592        return NULL;
2593
2594    /*
2595     * Check the zones suitable for the gfp_mask contain at least one
2596     * valid zone. It's possible to have an empty zonelist as a result
2597     * of GFP_THISNODE and a memoryless node
2598     */
2599    if (unlikely(!zonelist->_zonerefs->zone))
2600        return NULL;
2601
2602    /*
2603     * Will only have any effect when __GFP_KMEMCG is set. This is
2604     * verified in the (always inline) callee
2605     */
2606    if (!memcg_kmem_newpage_charge(gfp_mask, &memcg, order))
2607        return NULL;
2608
2609retry_cpuset:
2610    cpuset_mems_cookie = get_mems_allowed();
2611
2612    /* The preferred zone is used for statistics later */
2613    first_zones_zonelist(zonelist, high_zoneidx,
2614                nodemask ? : &cpuset_current_mems_allowed,
2615                &preferred_zone);
2616    if (!preferred_zone)
2617        goto out;
2618
2619#ifdef CONFIG_CMA
2620    if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
2621        alloc_flags |= ALLOC_CMA;
2622#endif
2623    /* First allocation attempt */
2624    page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
2625            zonelist, high_zoneidx, alloc_flags,
2626            preferred_zone, migratetype);
2627    if (unlikely(!page)) {
2628        /*
2629         * Runtime PM, block IO and its error handling path
2630         * can deadlock because I/O on the device might not
2631         * complete.
2632         */
2633        gfp_mask = memalloc_noio_flags(gfp_mask);
2634        page = __alloc_pages_slowpath(gfp_mask, order,
2635                zonelist, high_zoneidx, nodemask,
2636                preferred_zone, migratetype);
2637    }
2638
2639    trace_mm_page_alloc(page, order, gfp_mask, migratetype);
2640
2641out:
2642    /*
2643     * When updating a task's mems_allowed, it is possible to race with
2644     * parallel threads in such a way that an allocation can fail while
2645     * the mask is being updated. If a page allocation is about to fail,
2646     * check if the cpuset changed during allocation and if so, retry.
2647     */
2648    if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
2649        goto retry_cpuset;
2650
2651    memcg_kmem_commit_charge(page, memcg, order);
2652
2653    return page;
2654}
2655EXPORT_SYMBOL(__alloc_pages_nodemask);
2656
2657/*
2658 * Common helper functions.
2659 */
2660unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
2661{
2662    struct page *page;
2663
2664    /*
2665     * __get_free_pages() returns a 32-bit address, which cannot represent
2666     * a highmem page
2667     */
2668    VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
2669
2670    page = alloc_pages(gfp_mask, order);
2671    if (!page)
2672        return 0;
2673    return (unsigned long) page_address(page);
2674}
2675EXPORT_SYMBOL(__get_free_pages);
2676
2677unsigned long get_zeroed_page(gfp_t gfp_mask)
2678{
2679    return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
2680}
2681EXPORT_SYMBOL(get_zeroed_page);
2682
2683void __free_pages(struct page *page, unsigned int order)
2684{
2685    if (put_page_testzero(page)) {
2686        if (order == 0)
2687            free_hot_cold_page(page, 0);
2688        else
2689            __free_pages_ok(page, order);
2690    }
2691}
2692
2693EXPORT_SYMBOL(__free_pages);
2694
2695void free_pages(unsigned long addr, unsigned int order)
2696{
2697    if (addr != 0) {
2698        VM_BUG_ON(!virt_addr_valid((void *)addr));
2699        __free_pages(virt_to_page((void *)addr), order);
2700    }
2701}
2702
2703EXPORT_SYMBOL(free_pages);
2704
2705/*
2706 * __free_memcg_kmem_pages and free_memcg_kmem_pages will free
2707 * pages allocated with __GFP_KMEMCG.
2708 *
2709 * Those pages are accounted to a particular memcg, embedded in the
2710 * corresponding page_cgroup. To avoid adding a hit in the allocator to search
2711 * for that information only to find out that it is NULL for users who have no
2712 * interest in that whatsoever, we provide these functions.
2713 *
2714 * The caller knows better which flags it relies on.
2715 */
2716void __free_memcg_kmem_pages(struct page *page, unsigned int order)
2717{
2718    memcg_kmem_uncharge_pages(page, order);
2719    __free_pages(page, order);
2720}
2721
2722void free_memcg_kmem_pages(unsigned long addr, unsigned int order)
2723{
2724    if (addr != 0) {
2725        VM_BUG_ON(!virt_addr_valid((void *)addr));
2726        __free_memcg_kmem_pages(virt_to_page((void *)addr), order);
2727    }
2728}
2729
2730static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
2731{
2732    if (addr) {
2733        unsigned long alloc_end = addr + (PAGE_SIZE << order);
2734        unsigned long used = addr + PAGE_ALIGN(size);
2735
2736        split_page(virt_to_page((void *)addr), order);
2737        while (used < alloc_end) {
2738            free_page(used);
2739            used += PAGE_SIZE;
2740        }
2741    }
2742    return (void *)addr;
2743}
2744
2745/**
2746 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
2747 * @size: the number of bytes to allocate
2748 * @gfp_mask: GFP flags for the allocation
2749 *
2750 * This function is similar to alloc_pages(), except that it allocates the
2751 * minimum number of pages to satisfy the request. alloc_pages() can only
2752 * allocate memory in power-of-two pages.
2753 *
2754 * This function is also limited by MAX_ORDER.
2755 *
2756 * Memory allocated by this function must be released by free_pages_exact().
2757 */
2758void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
2759{
2760    unsigned int order = get_order(size);
2761    unsigned long addr;
2762
2763    addr = __get_free_pages(gfp_mask, order);
2764    return make_alloc_exact(addr, order, size);
2765}
2766EXPORT_SYMBOL(alloc_pages_exact);
2767
2768/**
2769 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
2770 * pages on a node.
2771 * @nid: the preferred node ID where memory should be allocated
2772 * @size: the number of bytes to allocate
2773 * @gfp_mask: GFP flags for the allocation
2774 *
2775 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
2776 * back.
2777 * Note this is not alloc_pages_exact_node() which allocates on a specific node,
2778 * but is not exact.
2779 */
2780void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
2781{
2782    unsigned order = get_order(size);
2783    struct page *p = alloc_pages_node(nid, gfp_mask, order);
2784    if (!p)
2785        return NULL;
2786    return make_alloc_exact((unsigned long)page_address(p), order, size);
2787}
2788EXPORT_SYMBOL(alloc_pages_exact_nid);
2789
2790/**
2791 * free_pages_exact - release memory allocated via alloc_pages_exact()
2792 * @virt: the value returned by alloc_pages_exact.
2793 * @size: size of allocation, same value as passed to alloc_pages_exact().
2794 *
2795 * Release the memory allocated by a previous call to alloc_pages_exact.
2796 */
2797void free_pages_exact(void *virt, size_t size)
2798{
2799    unsigned long addr = (unsigned long)virt;
2800    unsigned long end = addr + PAGE_ALIGN(size);
2801
2802    while (addr < end) {
2803        free_page(addr);
2804        addr += PAGE_SIZE;
2805    }
2806}
2807EXPORT_SYMBOL(free_pages_exact);
2808
2809/**
2810 * nr_free_zone_pages - count number of pages beyond high watermark
2811 * @offset: The zone index of the highest zone
2812 *
2813 * nr_free_zone_pages() counts the number of counts pages which are beyond the
2814 * high watermark within all zones at or below a given zone index. For each
2815 * zone, the number of pages is calculated as:
2816 * present_pages - high_pages
2817 */
2818static unsigned long nr_free_zone_pages(int offset)
2819{
2820    struct zoneref *z;
2821    struct zone *zone;
2822
2823    /* Just pick one node, since fallback list is circular */
2824    unsigned long sum = 0;
2825
2826    struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
2827
2828    for_each_zone_zonelist(zone, z, zonelist, offset) {
2829        unsigned long size = zone->managed_pages;
2830        unsigned long high = high_wmark_pages(zone);
2831        if (size > high)
2832            sum += size - high;
2833    }
2834
2835    return sum;
2836}
2837
2838/**
2839 * nr_free_buffer_pages - count number of pages beyond high watermark
2840 *
2841 * nr_free_buffer_pages() counts the number of pages which are beyond the high
2842 * watermark within ZONE_DMA and ZONE_NORMAL.
2843 */
2844unsigned long nr_free_buffer_pages(void)
2845{
2846    return nr_free_zone_pages(gfp_zone(GFP_USER));
2847}
2848EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
2849
2850/**
2851 * nr_free_pagecache_pages - count number of pages beyond high watermark
2852 *
2853 * nr_free_pagecache_pages() counts the number of pages which are beyond the
2854 * high watermark within all zones.
2855 */
2856unsigned long nr_free_pagecache_pages(void)
2857{
2858    return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
2859}
2860
2861static inline void show_node(struct zone *zone)
2862{
2863    if (IS_ENABLED(CONFIG_NUMA))
2864        printk("Node %d ", zone_to_nid(zone));
2865}
2866
2867void si_meminfo(struct sysinfo *val)
2868{
2869    val->totalram = totalram_pages;
2870    val->sharedram = 0;
2871    val->freeram = global_page_state(NR_FREE_PAGES);
2872    val->bufferram = nr_blockdev_pages();
2873    val->totalhigh = totalhigh_pages;
2874    val->freehigh = nr_free_highpages();
2875    val->mem_unit = PAGE_SIZE;
2876}
2877
2878EXPORT_SYMBOL(si_meminfo);
2879
2880#ifdef CONFIG_NUMA
2881void si_meminfo_node(struct sysinfo *val, int nid)
2882{
2883    pg_data_t *pgdat = NODE_DATA(nid);
2884
2885    val->totalram = pgdat->node_present_pages;
2886    val->freeram = node_page_state(nid, NR_FREE_PAGES);
2887#ifdef CONFIG_HIGHMEM
2888    val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].managed_pages;
2889    val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
2890            NR_FREE_PAGES);
2891#else
2892    val->totalhigh = 0;
2893    val->freehigh = 0;
2894#endif
2895    val->mem_unit = PAGE_SIZE;
2896}
2897#endif
2898
2899/*
2900 * Determine whether the node should be displayed or not, depending on whether
2901 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
2902 */
2903bool skip_free_areas_node(unsigned int flags, int nid)
2904{
2905    bool ret = false;
2906    unsigned int cpuset_mems_cookie;
2907
2908    if (!(flags & SHOW_MEM_FILTER_NODES))
2909        goto out;
2910
2911    do {
2912        cpuset_mems_cookie = get_mems_allowed();
2913        ret = !node_isset(nid, cpuset_current_mems_allowed);
2914    } while (!put_mems_allowed(cpuset_mems_cookie));
2915out:
2916    return ret;
2917}
2918
2919#define K(x) ((x) << (PAGE_SHIFT-10))
2920
2921static void show_migration_types(unsigned char type)
2922{
2923    static const char types[MIGRATE_TYPES] = {
2924        [MIGRATE_UNMOVABLE] = 'U',
2925        [MIGRATE_RECLAIMABLE] = 'E',
2926        [MIGRATE_MOVABLE] = 'M',
2927        [MIGRATE_RESERVE] = 'R',
2928#ifdef CONFIG_CMA
2929        [MIGRATE_CMA] = 'C',
2930#endif
2931#ifdef CONFIG_MEMORY_ISOLATION
2932        [MIGRATE_ISOLATE] = 'I',
2933#endif
2934    };
2935    char tmp[MIGRATE_TYPES + 1];
2936    char *p = tmp;
2937    int i;
2938
2939    for (i = 0; i < MIGRATE_TYPES; i++) {
2940        if (type & (1 << i))
2941            *p++ = types[i];
2942    }
2943
2944    *p = '\0';
2945    printk("(%s) ", tmp);
2946}
2947
2948/*
2949 * Show free area list (used inside shift_scroll-lock stuff)
2950 * We also calculate the percentage fragmentation. We do this by counting the
2951 * memory on each free list with the exception of the first item on the list.
2952 * Suppresses nodes that are not allowed by current's cpuset if
2953 * SHOW_MEM_FILTER_NODES is passed.
2954 */
2955void show_free_areas(unsigned int filter)
2956{
2957    int cpu;
2958    struct zone *zone;
2959
2960    for_each_populated_zone(zone) {
2961        if (skip_free_areas_node(filter, zone_to_nid(zone)))
2962            continue;
2963        show_node(zone);
2964        printk("%s per-cpu:\n", zone->name);
2965
2966        for_each_online_cpu(cpu) {
2967            struct per_cpu_pageset *pageset;
2968
2969            pageset = per_cpu_ptr(zone->pageset, cpu);
2970
2971            printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
2972                   cpu, pageset->pcp.high,
2973                   pageset->pcp.batch, pageset->pcp.count);
2974        }
2975    }
2976
2977    printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
2978        " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
2979        " unevictable:%lu"
2980        " dirty:%lu writeback:%lu unstable:%lu\n"
2981        " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
2982        " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
2983        " free_cma:%lu\n",
2984        global_page_state(NR_ACTIVE_ANON),
2985        global_page_state(NR_INACTIVE_ANON),
2986        global_page_state(NR_ISOLATED_ANON),
2987        global_page_state(NR_ACTIVE_FILE),
2988        global_page_state(NR_INACTIVE_FILE),
2989        global_page_state(NR_ISOLATED_FILE),
2990        global_page_state(NR_UNEVICTABLE),
2991        global_page_state(NR_FILE_DIRTY),
2992        global_page_state(NR_WRITEBACK),
2993        global_page_state(NR_UNSTABLE_NFS),
2994        global_page_state(NR_FREE_PAGES),
2995        global_page_state(NR_SLAB_RECLAIMABLE),
2996        global_page_state(NR_SLAB_UNRECLAIMABLE),
2997        global_page_state(NR_FILE_MAPPED),
2998        global_page_state(NR_SHMEM),
2999        global_page_state(NR_PAGETABLE),
3000        global_page_state(NR_BOUNCE),
3001        global_page_state(NR_FREE_CMA_PAGES));
3002
3003    for_each_populated_zone(zone) {
3004        int i;
3005
3006        if (skip_free_areas_node(filter, zone_to_nid(zone)))
3007            continue;
3008        show_node(zone);
3009        printk("%s"
3010            " free:%lukB"
3011            " min:%lukB"
3012            " low:%lukB"
3013            " high:%lukB"
3014            " active_anon:%lukB"
3015            " inactive_anon:%lukB"
3016            " active_file:%lukB"
3017            " inactive_file:%lukB"
3018            " unevictable:%lukB"
3019            " isolated(anon):%lukB"
3020            " isolated(file):%lukB"
3021            " present:%lukB"
3022            " managed:%lukB"
3023            " mlocked:%lukB"
3024            " dirty:%lukB"
3025            " writeback:%lukB"
3026            " mapped:%lukB"
3027            " shmem:%lukB"
3028            " slab_reclaimable:%lukB"
3029            " slab_unreclaimable:%lukB"
3030            " kernel_stack:%lukB"
3031            " pagetables:%lukB"
3032            " unstable:%lukB"
3033            " bounce:%lukB"
3034            " free_cma:%lukB"
3035            " writeback_tmp:%lukB"
3036            " pages_scanned:%lu"
3037            " all_unreclaimable? %s"
3038            "\n",
3039            zone->name,
3040            K(zone_page_state(zone, NR_FREE_PAGES)),
3041            K(min_wmark_pages(zone)),
3042            K(low_wmark_pages(zone)),
3043            K(high_wmark_pages(zone)),
3044            K(zone_page_state(zone, NR_ACTIVE_ANON)),
3045            K(zone_page_state(zone, NR_INACTIVE_ANON)),
3046            K(zone_page_state(zone, NR_ACTIVE_FILE)),
3047            K(zone_page_state(zone, NR_INACTIVE_FILE)),
3048            K(zone_page_state(zone, NR_UNEVICTABLE)),
3049            K(zone_page_state(zone, NR_ISOLATED_ANON)),
3050            K(zone_page_state(zone, NR_ISOLATED_FILE)),
3051            K(zone->present_pages),
3052            K(zone->managed_pages),
3053            K(zone_page_state(zone, NR_MLOCK)),
3054            K(zone_page_state(zone, NR_FILE_DIRTY)),
3055            K(zone_page_state(zone, NR_WRITEBACK)),
3056            K(zone_page_state(zone, NR_FILE_MAPPED)),
3057            K(zone_page_state(zone, NR_SHMEM)),
3058            K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
3059            K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
3060            zone_page_state(zone, NR_KERNEL_STACK) *
3061                THREAD_SIZE / 1024,
3062            K(zone_page_state(zone, NR_PAGETABLE)),
3063            K(zone_page_state(zone, NR_UNSTABLE_NFS)),
3064            K(zone_page_state(zone, NR_BOUNCE)),
3065            K(zone_page_state(zone, NR_FREE_CMA_PAGES)),
3066            K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
3067            zone->pages_scanned,
3068            (zone->all_unreclaimable ? "yes" : "no")
3069            );
3070        printk("lowmem_reserve[]:");
3071        for (i = 0; i < MAX_NR_ZONES; i++)
3072            printk(" %lu", zone->lowmem_reserve[i]);
3073        printk("\n");
3074    }
3075
3076    for_each_populated_zone(zone) {
3077         unsigned long nr[MAX_ORDER], flags, order, total = 0;
3078        unsigned char types[MAX_ORDER];
3079
3080        if (skip_free_areas_node(filter, zone_to_nid(zone)))
3081            continue;
3082        show_node(zone);
3083        printk("%s: ", zone->name);
3084
3085        spin_lock_irqsave(&zone->lock, flags);
3086        for (order = 0; order < MAX_ORDER; order++) {
3087            struct free_area *area = &zone->free_area[order];
3088            int type;
3089
3090            nr[order] = area->nr_free;
3091            total += nr[order] << order;
3092
3093            types[order] = 0;
3094            for (type = 0; type < MIGRATE_TYPES; type++) {
3095                if (!list_empty(&area->free_list[type]))
3096                    types[order] |= 1 << type;
3097            }
3098        }
3099        spin_unlock_irqrestore(&zone->lock, flags);
3100        for (order = 0; order < MAX_ORDER; order++) {
3101            printk("%lu*%lukB ", nr[order], K(1UL) << order);
3102            if (nr[order])
3103                show_migration_types(types[order]);
3104        }
3105        printk("= %lukB\n", K(total));
3106    }
3107
3108    printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
3109
3110    show_swap_cache_info();
3111}
3112
3113static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
3114{
3115    zoneref->zone = zone;
3116    zoneref->zone_idx = zone_idx(zone);
3117}
3118
3119/*
3120 * Builds allocation fallback zone lists.
3121 *
3122 * Add all populated zones of a node to the zonelist.
3123 */
3124static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
3125                int nr_zones, enum zone_type zone_type)
3126{
3127    struct zone *zone;
3128
3129    BUG_ON(zone_type >= MAX_NR_ZONES);
3130    zone_type++;
3131
3132    do {
3133        zone_type--;
3134        zone = pgdat->node_zones + zone_type;
3135        if (populated_zone(zone)) {
3136            zoneref_set_zone(zone,
3137                &zonelist->_zonerefs[nr_zones++]);
3138            check_highest_zone(zone_type);
3139        }
3140
3141    } while (zone_type);
3142    return nr_zones;
3143}
3144
3145
3146/*
3147 * zonelist_order:
3148 * 0 = automatic detection of better ordering.
3149 * 1 = order by ([node] distance, -zonetype)
3150 * 2 = order by (-zonetype, [node] distance)
3151 *
3152 * If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
3153 * the same zonelist. So only NUMA can configure this param.
3154 */
3155#define ZONELIST_ORDER_DEFAULT 0
3156#define ZONELIST_ORDER_NODE 1
3157#define ZONELIST_ORDER_ZONE 2
3158
3159/* zonelist order in the kernel.
3160 * set_zonelist_order() will set this to NODE or ZONE.
3161 */
3162static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
3163static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
3164
3165
3166#ifdef CONFIG_NUMA
3167/* The value user specified ....changed by config */
3168static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
3169/* string for sysctl */
3170#define NUMA_ZONELIST_ORDER_LEN 16
3171char numa_zonelist_order[16] = "default";
3172
3173/*
3174 * interface for configure zonelist ordering.
3175 * command line option "numa_zonelist_order"
3176 * = "[dD]efault - default, automatic configuration.
3177 * = "[nN]ode - order by node locality, then by zone within node
3178 * = "[zZ]one - order by zone, then by locality within zone
3179 */
3180
3181static int __parse_numa_zonelist_order(char *s)
3182{
3183    if (*s == 'd' || *s == 'D') {
3184        user_zonelist_order = ZONELIST_ORDER_DEFAULT;
3185    } else if (*s == 'n' || *s == 'N') {
3186        user_zonelist_order = ZONELIST_ORDER_NODE;
3187    } else if (*s == 'z' || *s == 'Z') {
3188        user_zonelist_order = ZONELIST_ORDER_ZONE;
3189    } else {
3190        printk(KERN_WARNING
3191            "Ignoring invalid numa_zonelist_order value: "
3192            "%s\n", s);
3193        return -EINVAL;
3194    }
3195    return 0;
3196}
3197
3198static __init int setup_numa_zonelist_order(char *s)
3199{
3200    int ret;
3201
3202    if (!s)
3203        return 0;
3204
3205    ret = __parse_numa_zonelist_order(s);
3206    if (ret == 0)
3207        strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
3208
3209    return ret;
3210}
3211early_param("numa_zonelist_order", setup_numa_zonelist_order);
3212
3213/*
3214 * sysctl handler for numa_zonelist_order
3215 */
3216int numa_zonelist_order_handler(ctl_table *table, int write,
3217        void __user *buffer, size_t *length,
3218        loff_t *ppos)
3219{
3220    char saved_string[NUMA_ZONELIST_ORDER_LEN];
3221    int ret;
3222    static DEFINE_MUTEX(zl_order_mutex);
3223
3224    mutex_lock(&zl_order_mutex);
3225    if (write)
3226        strcpy(saved_string, (char*)table->data);
3227    ret = proc_dostring(table, write, buffer, length, ppos);
3228    if (ret)
3229        goto out;
3230    if (write) {
3231        int oldval = user_zonelist_order;
3232        if (__parse_numa_zonelist_order((char*)table->data)) {
3233            /*
3234             * bogus value. restore saved string
3235             */
3236            strncpy((char*)table->data, saved_string,
3237                NUMA_ZONELIST_ORDER_LEN);
3238            user_zonelist_order = oldval;
3239        } else if (oldval != user_zonelist_order) {
3240            mutex_lock(&zonelists_mutex);
3241            build_all_zonelists(NULL, NULL);
3242            mutex_unlock(&zonelists_mutex);
3243        }
3244    }
3245out:
3246    mutex_unlock(&zl_order_mutex);
3247    return ret;
3248}
3249
3250
3251#define MAX_NODE_LOAD (nr_online_nodes)
3252static int node_load[MAX_NUMNODES];
3253
3254/**
3255 * find_next_best_node - find the next node that should appear in a given node's fallback list
3256 * @node: node whose fallback list we're appending
3257 * @used_node_mask: nodemask_t of already used nodes
3258 *
3259 * We use a number of factors to determine which is the next node that should
3260 * appear on a given node's fallback list. The node should not have appeared
3261 * already in @node's fallback list, and it should be the next closest node
3262 * according to the distance array (which contains arbitrary distance values
3263 * from each node to each node in the system), and should also prefer nodes
3264 * with no CPUs, since presumably they'll have very little allocation pressure
3265 * on them otherwise.
3266 * It returns -1 if no node is found.
3267 */
3268static int find_next_best_node(int node, nodemask_t *used_node_mask)
3269{
3270    int n, val;
3271    int min_val = INT_MAX;
3272    int best_node = NUMA_NO_NODE;
3273    const struct cpumask *tmp = cpumask_of_node(0);
3274
3275    /* Use the local node if we haven't already */
3276    if (!node_isset(node, *used_node_mask)) {
3277        node_set(node, *used_node_mask);
3278        return node;
3279    }
3280
3281    for_each_node_state(n, N_MEMORY) {
3282
3283        /* Don't want a node to appear more than once */
3284        if (node_isset(n, *used_node_mask))
3285            continue;
3286
3287        /* Use the distance array to find the distance */
3288        val = node_distance(node, n);
3289
3290        /* Penalize nodes under us ("prefer the next node") */
3291        val += (n < node);
3292
3293        /* Give preference to headless and unused nodes */
3294        tmp = cpumask_of_node(n);
3295        if (!cpumask_empty(tmp))
3296            val += PENALTY_FOR_NODE_WITH_CPUS;
3297
3298        /* Slight preference for less loaded node */
3299        val *= (MAX_NODE_LOAD*MAX_NUMNODES);
3300        val += node_load[n];
3301
3302        if (val < min_val) {
3303            min_val = val;
3304            best_node = n;
3305        }
3306    }
3307
3308    if (best_node >= 0)
3309        node_set(best_node, *used_node_mask);
3310
3311    return best_node;
3312}
3313
3314
3315/*
3316 * Build zonelists ordered by node and zones within node.
3317 * This results in maximum locality--normal zone overflows into local
3318 * DMA zone, if any--but risks exhausting DMA zone.
3319 */
3320static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
3321{
3322    int j;
3323    struct zonelist *zonelist;
3324
3325    zonelist = &pgdat->node_zonelists[0];
3326    for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
3327        ;
3328    j = build_zonelists_node(NODE_DATA(node), zonelist, j,
3329                            MAX_NR_ZONES - 1);
3330    zonelist->_zonerefs[j].zone = NULL;
3331    zonelist->_zonerefs[j].zone_idx = 0;
3332}
3333
3334/*
3335 * Build gfp_thisnode zonelists
3336 */
3337static void build_thisnode_zonelists(pg_data_t *pgdat)
3338{
3339    int j;
3340    struct zonelist *zonelist;
3341
3342    zonelist = &pgdat->node_zonelists[1];
3343    j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
3344    zonelist->_zonerefs[j].zone = NULL;
3345    zonelist->_zonerefs[j].zone_idx = 0;
3346}
3347
3348/*
3349 * Build zonelists ordered by zone and nodes within zones.
3350 * This results in conserving DMA zone[s] until all Normal memory is
3351 * exhausted, but results in overflowing to remote node while memory
3352 * may still exist in local DMA zone.
3353 */
3354static int node_order[MAX_NUMNODES];
3355
3356static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
3357{
3358    int pos, j, node;
3359    int zone_type; /* needs to be signed */
3360    struct zone *z;
3361    struct zonelist *zonelist;
3362
3363    zonelist = &pgdat->node_zonelists[0];
3364    pos = 0;
3365    for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
3366        for (j = 0; j < nr_nodes; j++) {
3367            node = node_order[j];
3368            z = &NODE_DATA(node)->node_zones[zone_type];
3369            if (populated_zone(z)) {
3370                zoneref_set_zone(z,
3371                    &zonelist->_zonerefs[pos++]);
3372                check_highest_zone(zone_type);
3373            }
3374        }
3375    }
3376    zonelist->_zonerefs[pos].zone = NULL;
3377    zonelist->_zonerefs[pos].zone_idx = 0;
3378}
3379
3380static int default_zonelist_order(void)
3381{
3382    int nid, zone_type;
3383    unsigned long low_kmem_size,total_size;
3384    struct zone *z;
3385    int average_size;
3386    /*
3387         * ZONE_DMA and ZONE_DMA32 can be very small area in the system.
3388     * If they are really small and used heavily, the system can fall
3389     * into OOM very easily.
3390     * This function detect ZONE_DMA/DMA32 size and configures zone order.
3391     */
3392    /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
3393    low_kmem_size = 0;
3394    total_size = 0;
3395    for_each_online_node(nid) {
3396        for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3397            z = &NODE_DATA(nid)->node_zones[zone_type];
3398            if (populated_zone(z)) {
3399                if (zone_type < ZONE_NORMAL)
3400                    low_kmem_size += z->present_pages;
3401                total_size += z->present_pages;
3402            } else if (zone_type == ZONE_NORMAL) {
3403                /*
3404                 * If any node has only lowmem, then node order
3405                 * is preferred to allow kernel allocations
3406                 * locally; otherwise, they can easily infringe
3407                 * on other nodes when there is an abundance of
3408                 * lowmem available to allocate from.
3409                 */
3410                return ZONELIST_ORDER_NODE;
3411            }
3412        }
3413    }
3414    if (!low_kmem_size || /* there are no DMA area. */
3415        low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
3416        return ZONELIST_ORDER_NODE;
3417    /*
3418     * look into each node's config.
3419       * If there is a node whose DMA/DMA32 memory is very big area on
3420      * local memory, NODE_ORDER may be suitable.
3421         */
3422    average_size = total_size /
3423                (nodes_weight(node_states[N_MEMORY]) + 1);
3424    for_each_online_node(nid) {
3425        low_kmem_size = 0;
3426        total_size = 0;
3427        for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3428            z = &NODE_DATA(nid)->node_zones[zone_type];
3429            if (populated_zone(z)) {
3430                if (zone_type < ZONE_NORMAL)
3431                    low_kmem_size += z->present_pages;
3432                total_size += z->present_pages;
3433            }
3434        }
3435        if (low_kmem_size &&
3436            total_size > average_size && /* ignore small node */
3437            low_kmem_size > total_size * 70/100)
3438            return ZONELIST_ORDER_NODE;
3439    }
3440    return ZONELIST_ORDER_ZONE;
3441}
3442
3443static void set_zonelist_order(void)
3444{
3445    if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
3446        current_zonelist_order = default_zonelist_order();
3447    else
3448        current_zonelist_order = user_zonelist_order;
3449}
3450
3451static void build_zonelists(pg_data_t *pgdat)
3452{
3453    int j, node, load;
3454    enum zone_type i;
3455    nodemask_t used_mask;
3456    int local_node, prev_node;
3457    struct zonelist *zonelist;
3458    int order = current_zonelist_order;
3459
3460    /* initialize zonelists */
3461    for (i = 0; i < MAX_ZONELISTS; i++) {
3462        zonelist = pgdat->node_zonelists + i;
3463        zonelist->_zonerefs[0].zone = NULL;
3464        zonelist->_zonerefs[0].zone_idx = 0;
3465    }
3466
3467    /* NUMA-aware ordering of nodes */
3468    local_node = pgdat->node_id;
3469    load = nr_online_nodes;
3470    prev_node = local_node;
3471    nodes_clear(used_mask);
3472
3473    memset(node_order, 0, sizeof(node_order));
3474    j = 0;
3475
3476    while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
3477        /*
3478         * We don't want to pressure a particular node.
3479         * So adding penalty to the first node in same
3480         * distance group to make it round-robin.
3481         */
3482        if (node_distance(local_node, node) !=
3483            node_distance(local_node, prev_node))
3484            node_load[node] = load;
3485
3486        prev_node = node;
3487        load--;
3488        if (order == ZONELIST_ORDER_NODE)
3489            build_zonelists_in_node_order(pgdat, node);
3490        else
3491            node_order[j++] = node; /* remember order */
3492    }
3493
3494    if (order == ZONELIST_ORDER_ZONE) {
3495        /* calculate node order -- i.e., DMA last! */
3496        build_zonelists_in_zone_order(pgdat, j);
3497    }
3498
3499    build_thisnode_zonelists(pgdat);
3500}
3501
3502/* Construct the zonelist performance cache - see further mmzone.h */
3503static void build_zonelist_cache(pg_data_t *pgdat)
3504{
3505    struct zonelist *zonelist;
3506    struct zonelist_cache *zlc;
3507    struct zoneref *z;
3508
3509    zonelist = &pgdat->node_zonelists[0];
3510    zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
3511    bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
3512    for (z = zonelist->_zonerefs; z->zone; z++)
3513        zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
3514}
3515
3516#ifdef CONFIG_HAVE_MEMORYLESS_NODES
3517/*
3518 * Return node id of node used for "local" allocations.
3519 * I.e., first node id of first zone in arg node's generic zonelist.
3520 * Used for initializing percpu 'numa_mem', which is used primarily
3521 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
3522 */
3523int local_memory_node(int node)
3524{
3525    struct zone *zone;
3526
3527    (void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
3528                   gfp_zone(GFP_KERNEL),
3529                   NULL,
3530                   &zone);
3531    return zone->node;
3532}
3533#endif
3534
3535#else /* CONFIG_NUMA */
3536
3537static void set_zonelist_order(void)
3538{
3539    current_zonelist_order = ZONELIST_ORDER_ZONE;
3540}
3541
3542static void build_zonelists(pg_data_t *pgdat)
3543{
3544    int node, local_node;
3545    enum zone_type j;
3546    struct zonelist *zonelist;
3547
3548    local_node = pgdat->node_id;
3549
3550    zonelist = &pgdat->node_zonelists[0];
3551    j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
3552
3553    /*
3554     * Now we build the zonelist so that it contains the zones
3555     * of all the other nodes.
3556     * We don't want to pressure a particular node, so when
3557     * building the zones for node N, we make sure that the
3558     * zones coming right after the local ones are those from
3559     * node N+1 (modulo N)
3560     */
3561    for (node = local_node + 1; node < MAX_NUMNODES; node++) {
3562        if (!node_online(node))
3563            continue;
3564        j = build_zonelists_node(NODE_DATA(node), zonelist, j,
3565                            MAX_NR_ZONES - 1);
3566    }
3567    for (node = 0; node < local_node; node++) {
3568        if (!node_online(node))
3569            continue;
3570        j = build_zonelists_node(NODE_DATA(node), zonelist, j,
3571                            MAX_NR_ZONES - 1);
3572    }
3573
3574    zonelist->_zonerefs[j].zone = NULL;
3575    zonelist->_zonerefs[j].zone_idx = 0;
3576}
3577
3578/* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
3579static void build_zonelist_cache(pg_data_t *pgdat)
3580{
3581    pgdat->node_zonelists[0].zlcache_ptr = NULL;
3582}
3583
3584#endif /* CONFIG_NUMA */
3585
3586/*
3587 * Boot pageset table. One per cpu which is going to be used for all
3588 * zones and all nodes. The parameters will be set in such a way
3589 * that an item put on a list will immediately be handed over to
3590 * the buddy list. This is safe since pageset manipulation is done
3591 * with interrupts disabled.
3592 *
3593 * The boot_pagesets must be kept even after bootup is complete for
3594 * unused processors and/or zones. They do play a role for bootstrapping
3595 * hotplugged processors.
3596 *
3597 * zoneinfo_show() and maybe other functions do
3598 * not check if the processor is online before following the pageset pointer.
3599 * Other parts of the kernel may not check if the zone is available.
3600 */
3601static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
3602static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
3603static void setup_zone_pageset(struct zone *zone);
3604
3605/*
3606 * Global mutex to protect against size modification of zonelists
3607 * as well as to serialize pageset setup for the new populated zone.
3608 */
3609DEFINE_MUTEX(zonelists_mutex);
3610
3611/* return values int ....just for stop_machine() */
3612static int __build_all_zonelists(void *data)
3613{
3614    int nid;
3615    int cpu;
3616    pg_data_t *self = data;
3617
3618#ifdef CONFIG_NUMA
3619    memset(node_load, 0, sizeof(node_load));
3620#endif
3621
3622    if (self && !node_online(self->node_id)) {
3623        build_zonelists(self);
3624        build_zonelist_cache(self);
3625    }
3626
3627    for_each_online_node(nid) {
3628        pg_data_t *pgdat = NODE_DATA(nid);
3629
3630        build_zonelists(pgdat);
3631        build_zonelist_cache(pgdat);
3632    }
3633
3634    /*
3635     * Initialize the boot_pagesets that are going to be used
3636     * for bootstrapping processors. The real pagesets for
3637     * each zone will be allocated later when the per cpu
3638     * allocator is available.
3639     *
3640     * boot_pagesets are used also for bootstrapping offline
3641     * cpus if the system is already booted because the pagesets
3642     * are needed to initialize allocators on a specific cpu too.
3643     * F.e. the percpu allocator needs the page allocator which
3644     * needs the percpu allocator in order to allocate its pagesets
3645     * (a chicken-egg dilemma).
3646     */
3647    for_each_possible_cpu(cpu) {
3648        setup_pageset(&per_cpu(boot_pageset, cpu), 0);
3649
3650#ifdef CONFIG_HAVE_MEMORYLESS_NODES
3651        /*
3652         * We now know the "local memory node" for each node--
3653         * i.e., the node of the first zone in the generic zonelist.
3654         * Set up numa_mem percpu variable for on-line cpus. During
3655         * boot, only the boot cpu should be on-line; we'll init the
3656         * secondary cpus' numa_mem as they come on-line. During
3657         * node/memory hotplug, we'll fixup all on-line cpus.
3658         */
3659        if (cpu_online(cpu))
3660            set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
3661#endif
3662    }
3663
3664    return 0;
3665}
3666
3667/*
3668 * Called with zonelists_mutex held always
3669 * unless system_state == SYSTEM_BOOTING.
3670 */
3671void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone)
3672{
3673    set_zonelist_order();
3674
3675    if (system_state == SYSTEM_BOOTING) {
3676        __build_all_zonelists(NULL);
3677        mminit_verify_zonelist();
3678        cpuset_init_current_mems_allowed();
3679    } else {
3680        /* we have to stop all cpus to guarantee there is no user
3681           of zonelist */
3682#ifdef CONFIG_MEMORY_HOTPLUG
3683        if (zone)
3684            setup_zone_pageset(zone);
3685#endif
3686        stop_machine(__build_all_zonelists, pgdat, NULL);
3687        /* cpuset refresh routine should be here */
3688    }
3689    vm_total_pages = nr_free_pagecache_pages();
3690    /*
3691     * Disable grouping by mobility if the number of pages in the
3692     * system is too low to allow the mechanism to work. It would be
3693     * more accurate, but expensive to check per-zone. This check is
3694     * made on memory-hotadd so a system can start with mobility
3695     * disabled and enable it later
3696     */
3697    if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
3698        page_group_by_mobility_disabled = 1;
3699    else
3700        page_group_by_mobility_disabled = 0;
3701
3702    printk("Built %i zonelists in %s order, mobility grouping %s. "
3703        "Total pages: %ld\n",
3704            nr_online_nodes,
3705            zonelist_order_name[current_zonelist_order],
3706            page_group_by_mobility_disabled ? "off" : "on",
3707            vm_total_pages);
3708#ifdef CONFIG_NUMA
3709    printk("Policy zone: %s\n", zone_names[policy_zone]);
3710#endif
3711}
3712
3713/*
3714 * Helper functions to size the waitqueue hash table.
3715 * Essentially these want to choose hash table sizes sufficiently
3716 * large so that collisions trying to wait on pages are rare.
3717 * But in fact, the number of active page waitqueues on typical
3718 * systems is ridiculously low, less than 200. So this is even
3719 * conservative, even though it seems large.
3720 *
3721 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
3722 * waitqueues, i.e. the size of the waitq table given the number of pages.
3723 */
3724#define PAGES_PER_WAITQUEUE 256
3725
3726#ifndef CONFIG_MEMORY_HOTPLUG
3727static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3728{
3729    unsigned long size = 1;
3730
3731    pages /= PAGES_PER_WAITQUEUE;
3732
3733    while (size < pages)
3734        size <<= 1;
3735
3736    /*
3737     * Once we have dozens or even hundreds of threads sleeping
3738     * on IO we've got bigger problems than wait queue collision.
3739     * Limit the size of the wait table to a reasonable size.
3740     */
3741    size = min(size, 4096UL);
3742
3743    return max(size, 4UL);
3744}
3745#else
3746/*
3747 * A zone's size might be changed by hot-add, so it is not possible to determine
3748 * a suitable size for its wait_table. So we use the maximum size now.
3749 *
3750 * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie:
3751 *
3752 * i386 (preemption config) : 4096 x 16 = 64Kbyte.
3753 * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
3754 * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte.
3755 *
3756 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
3757 * or more by the traditional way. (See above). It equals:
3758 *
3759 * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte.
3760 * ia64(16K page size) : = ( 8G + 4M)byte.
3761 * powerpc (64K page size) : = (32G +16M)byte.
3762 */
3763static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3764{
3765    return 4096UL;
3766}
3767#endif
3768
3769/*
3770 * This is an integer logarithm so that shifts can be used later
3771 * to extract the more random high bits from the multiplicative
3772 * hash function before the remainder is taken.
3773 */
3774static inline unsigned long wait_table_bits(unsigned long size)
3775{
3776    return ffz(~size);
3777}
3778
3779#define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
3780
3781/*
3782 * Check if a pageblock contains reserved pages
3783 */
3784static int pageblock_is_reserved(unsigned long start_pfn, unsigned long end_pfn)
3785{
3786    unsigned long pfn;
3787
3788    for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3789        if (!pfn_valid_within(pfn) || PageReserved(pfn_to_page(pfn)))
3790            return 1;
3791    }
3792    return 0;
3793}
3794
3795/*
3796 * Mark a number of pageblocks as MIGRATE_RESERVE. The number
3797 * of blocks reserved is based on min_wmark_pages(zone). The memory within
3798 * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
3799 * higher will lead to a bigger reserve which will get freed as contiguous
3800 * blocks as reclaim kicks in
3801 */
3802static void setup_zone_migrate_reserve(struct zone *zone)
3803{
3804    unsigned long start_pfn, pfn, end_pfn, block_end_pfn;
3805    struct page *page;
3806    unsigned long block_migratetype;
3807    int reserve;
3808
3809    /*
3810     * Get the start pfn, end pfn and the number of blocks to reserve
3811     * We have to be careful to be aligned to pageblock_nr_pages to
3812     * make sure that we always check pfn_valid for the first page in
3813     * the block.
3814     */
3815    start_pfn = zone->zone_start_pfn;
3816    end_pfn = zone_end_pfn(zone);
3817    start_pfn = roundup(start_pfn, pageblock_nr_pages);
3818    reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
3819                            pageblock_order;
3820
3821    /*
3822     * Reserve blocks are generally in place to help high-order atomic
3823     * allocations that are short-lived. A min_free_kbytes value that
3824     * would result in more than 2 reserve blocks for atomic allocations
3825     * is assumed to be in place to help anti-fragmentation for the
3826     * future allocation of hugepages at runtime.
3827     */
3828    reserve = min(2, reserve);
3829
3830    for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
3831        if (!pfn_valid(pfn))
3832            continue;
3833        page = pfn_to_page(pfn);
3834
3835        /* Watch out for overlapping nodes */
3836        if (page_to_nid(page) != zone_to_nid(zone))
3837            continue;
3838
3839        block_migratetype = get_pageblock_migratetype(page);
3840
3841        /* Only test what is necessary when the reserves are not met */
3842        if (reserve > 0) {
3843            /*
3844             * Blocks with reserved pages will never free, skip
3845             * them.
3846             */
3847            block_end_pfn = min(pfn + pageblock_nr_pages, end_pfn);
3848            if (pageblock_is_reserved(pfn, block_end_pfn))
3849                continue;
3850
3851            /* If this block is reserved, account for it */
3852            if (block_migratetype == MIGRATE_RESERVE) {
3853                reserve--;
3854                continue;
3855            }
3856
3857            /* Suitable for reserving if this block is movable */
3858            if (block_migratetype == MIGRATE_MOVABLE) {
3859                set_pageblock_migratetype(page,
3860                            MIGRATE_RESERVE);
3861                move_freepages_block(zone, page,
3862                            MIGRATE_RESERVE);
3863                reserve--;
3864                continue;
3865            }
3866        }
3867
3868        /*
3869         * If the reserve is met and this is a previous reserved block,
3870         * take it back
3871         */
3872        if (block_migratetype == MIGRATE_RESERVE) {
3873            set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3874            move_freepages_block(zone, page, MIGRATE_MOVABLE);
3875        }
3876    }
3877}
3878
3879/*
3880 * Initially all pages are reserved - free ones are freed
3881 * up by free_all_bootmem() once the early boot process is
3882 * done. Non-atomic initialization, single-pass.
3883 */
3884void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
3885        unsigned long start_pfn, enum memmap_context context)
3886{
3887    struct page *page;
3888    unsigned long end_pfn = start_pfn + size;
3889    unsigned long pfn;
3890    struct zone *z;
3891
3892    if (highest_memmap_pfn < end_pfn - 1)
3893        highest_memmap_pfn = end_pfn - 1;
3894
3895    z = &NODE_DATA(nid)->node_zones[zone];
3896    for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3897        /*
3898         * There can be holes in boot-time mem_map[]s
3899         * handed to this function. They do not
3900         * exist on hotplugged memory.
3901         */
3902        if (context == MEMMAP_EARLY) {
3903            if (!early_pfn_valid(pfn))
3904                continue;
3905            if (!early_pfn_in_nid(pfn, nid))
3906                continue;
3907        }
3908        page = pfn_to_page(pfn);
3909        set_page_links(page, zone, nid, pfn);
3910        mminit_verify_page_links(page, zone, nid, pfn);
3911        init_page_count(page);
3912        page_mapcount_reset(page);
3913        page_nid_reset_last(page);
3914        SetPageReserved(page);
3915        /*
3916         * Mark the block movable so that blocks are reserved for
3917         * movable at startup. This will force kernel allocations
3918         * to reserve their blocks rather than leaking throughout
3919         * the address space during boot when many long-lived
3920         * kernel allocations are made. Later some blocks near
3921         * the start are marked MIGRATE_RESERVE by
3922         * setup_zone_migrate_reserve()
3923         *
3924         * bitmap is created for zone's valid pfn range. but memmap
3925         * can be created for invalid pages (for alignment)
3926         * check here not to call set_pageblock_migratetype() against
3927         * pfn out of zone.
3928         */
3929        if ((z->zone_start_pfn <= pfn)
3930            && (pfn < zone_end_pfn(z))
3931            && !(pfn & (pageblock_nr_pages - 1)))
3932            set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3933
3934        INIT_LIST_HEAD(&page->lru);
3935#ifdef WANT_PAGE_VIRTUAL
3936        /* The shift won't overflow because ZONE_NORMAL is below 4G. */
3937        if (!is_highmem_idx(zone))
3938            set_page_address(page, __va(pfn << PAGE_SHIFT));
3939#endif
3940    }
3941}
3942
3943static void __meminit zone_init_free_lists(struct zone *zone)
3944{
3945    int order, t;
3946    for_each_migratetype_order(order, t) {
3947        INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
3948        zone->free_area[order].nr_free = 0;
3949    }
3950}
3951
3952#ifndef __HAVE_ARCH_MEMMAP_INIT
3953#define memmap_init(size, nid, zone, start_pfn) \
3954    memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
3955#endif
3956
3957static int __meminit zone_batchsize(struct zone *zone)
3958{
3959#ifdef CONFIG_MMU
3960    int batch;
3961
3962    /*
3963     * The per-cpu-pages pools are set to around 1000th of the
3964     * size of the zone. But no more than 1/2 of a meg.
3965     *
3966     * OK, so we don't know how big the cache is. So guess.
3967     */
3968    batch = zone->managed_pages / 1024;
3969    if (batch * PAGE_SIZE > 512 * 1024)
3970        batch = (512 * 1024) / PAGE_SIZE;
3971    batch /= 4; /* We effectively *= 4 below */
3972    if (batch < 1)
3973        batch = 1;
3974
3975    /*
3976     * Clamp the batch to a 2^n - 1 value. Having a power
3977     * of 2 value was found to be more likely to have
3978     * suboptimal cache aliasing properties in some cases.
3979     *
3980     * For example if 2 tasks are alternately allocating
3981     * batches of pages, one task can end up with a lot
3982     * of pages of one half of the possible page colors
3983     * and the other with pages of the other colors.
3984     */
3985    batch = rounddown_pow_of_two(batch + batch/2) - 1;
3986
3987    return batch;
3988
3989#else
3990    /* The deferral and batching of frees should be suppressed under NOMMU
3991     * conditions.
3992     *
3993     * The problem is that NOMMU needs to be able to allocate large chunks
3994     * of contiguous memory as there's no hardware page translation to
3995     * assemble apparent contiguous memory from discontiguous pages.
3996     *
3997     * Queueing large contiguous runs of pages for batching, however,
3998     * causes the pages to actually be freed in smaller chunks. As there
3999     * can be a significant delay between the individual batches being
4000     * recycled, this leads to the once large chunks of space being
4001     * fragmented and becoming unavailable for high-order allocations.
4002     */
4003    return 0;
4004#endif
4005}
4006
4007static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
4008{
4009    struct per_cpu_pages *pcp;
4010    int migratetype;
4011
4012    memset(p, 0, sizeof(*p));
4013
4014    pcp = &p->pcp;
4015    pcp->count = 0;
4016    pcp->high = 6 * batch;
4017    pcp->batch = max(1UL, 1 * batch);
4018    for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
4019        INIT_LIST_HEAD(&pcp->lists[migratetype]);
4020}
4021
4022/*
4023 * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
4024 * to the value high for the pageset p.
4025 */
4026
4027static void setup_pagelist_highmark(struct per_cpu_pageset *p,
4028                unsigned long high)
4029{
4030    struct per_cpu_pages *pcp;
4031
4032    pcp = &p->pcp;
4033    pcp->high = high;
4034    pcp->batch = max(1UL, high/4);
4035    if ((high/4) > (PAGE_SHIFT * 8))
4036        pcp->batch = PAGE_SHIFT * 8;
4037}
4038
4039static void __meminit setup_zone_pageset(struct zone *zone)
4040{
4041    int cpu;
4042
4043    zone->pageset = alloc_percpu(struct per_cpu_pageset);
4044
4045    for_each_possible_cpu(cpu) {
4046        struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
4047
4048        setup_pageset(pcp, zone_batchsize(zone));
4049
4050        if (percpu_pagelist_fraction)
4051            setup_pagelist_highmark(pcp,
4052                (zone->managed_pages /
4053                    percpu_pagelist_fraction));
4054    }
4055}
4056
4057/*
4058 * Allocate per cpu pagesets and initialize them.
4059 * Before this call only boot pagesets were available.
4060 */
4061void __init setup_per_cpu_pageset(void)
4062{
4063    struct zone *zone;
4064
4065    for_each_populated_zone(zone)
4066        setup_zone_pageset(zone);
4067}
4068
4069static noinline __init_refok
4070int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
4071{
4072    int i;
4073    struct pglist_data *pgdat = zone->zone_pgdat;
4074    size_t alloc_size;
4075
4076    /*
4077     * The per-page waitqueue mechanism uses hashed waitqueues
4078     * per zone.
4079     */
4080    zone->wait_table_hash_nr_entries =
4081         wait_table_hash_nr_entries(zone_size_pages);
4082    zone->wait_table_bits =
4083        wait_table_bits(zone->wait_table_hash_nr_entries);
4084    alloc_size = zone->wait_table_hash_nr_entries
4085                    * sizeof(wait_queue_head_t);
4086
4087    if (!slab_is_available()) {
4088        zone->wait_table = (wait_queue_head_t *)
4089            alloc_bootmem_node_nopanic(pgdat, alloc_size);
4090    } else {
4091        /*
4092         * This case means that a zone whose size was 0 gets new memory
4093         * via memory hot-add.
4094         * But it may be the case that a new node was hot-added. In
4095         * this case vmalloc() will not be able to use this new node's
4096         * memory - this wait_table must be initialized to use this new
4097         * node itself as well.
4098         * To use this new node's memory, further consideration will be
4099         * necessary.
4100         */
4101        zone->wait_table = vmalloc(alloc_size);
4102    }
4103    if (!zone->wait_table)
4104        return -ENOMEM;
4105
4106    for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
4107        init_waitqueue_head(zone->wait_table + i);
4108
4109    return 0;
4110}
4111
4112static __meminit void zone_pcp_init(struct zone *zone)
4113{
4114    /*
4115     * per cpu subsystem is not up at this point. The following code
4116     * relies on the ability of the linker to provide the
4117     * offset of a (static) per cpu variable into the per cpu area.
4118     */
4119    zone->pageset = &boot_pageset;
4120
4121    if (zone->present_pages)
4122        printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n",
4123            zone->name, zone->present_pages,
4124                     zone_batchsize(zone));
4125}
4126
4127int __meminit init_currently_empty_zone(struct zone *zone,
4128                    unsigned long zone_start_pfn,
4129                    unsigned long size,
4130                    enum memmap_context context)
4131{
4132    struct pglist_data *pgdat = zone->zone_pgdat;
4133    int ret;
4134    ret = zone_wait_table_init(zone, size);
4135    if (ret)
4136        return ret;
4137    pgdat->nr_zones = zone_idx(zone) + 1;
4138
4139    zone->zone_start_pfn = zone_start_pfn;
4140
4141    mminit_dprintk(MMINIT_TRACE, "memmap_init",
4142            "Initialising map node %d zone %lu pfns %lu -> %lu\n",
4143            pgdat->node_id,
4144            (unsigned long)zone_idx(zone),
4145            zone_start_pfn, (zone_start_pfn + size));
4146
4147    zone_init_free_lists(zone);
4148
4149    return 0;
4150}
4151
4152#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4153#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
4154/*
4155 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
4156 * Architectures may implement their own version but if add_active_range()
4157 * was used and there are no special requirements, this is a convenient
4158 * alternative
4159 */
4160int __meminit __early_pfn_to_nid(unsigned long pfn)
4161{
4162    unsigned long start_pfn, end_pfn;
4163    int i, nid;
4164
4165    for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
4166        if (start_pfn <= pfn && pfn < end_pfn)
4167            return nid;
4168    /* This is a memory hole */
4169    return -1;
4170}
4171#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
4172
4173int __meminit early_pfn_to_nid(unsigned long pfn)
4174{
4175    int nid;
4176
4177    nid = __early_pfn_to_nid(pfn);
4178    if (nid >= 0)
4179        return nid;
4180    /* just returns 0 */
4181    return 0;
4182}
4183
4184#ifdef CONFIG_NODES_SPAN_OTHER_NODES
4185bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
4186{
4187    int nid;
4188
4189    nid = __early_pfn_to_nid(pfn);
4190    if (nid >= 0 && nid != node)
4191        return false;
4192    return true;
4193}
4194#endif
4195
4196/**
4197 * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
4198 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
4199 * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
4200 *
4201 * If an architecture guarantees that all ranges registered with
4202 * add_active_ranges() contain no holes and may be freed, this
4203 * this function may be used instead of calling free_bootmem() manually.
4204 */
4205void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
4206{
4207    unsigned long start_pfn, end_pfn;
4208    int i, this_nid;
4209
4210    for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
4211        start_pfn = min(start_pfn, max_low_pfn);
4212        end_pfn = min(end_pfn, max_low_pfn);
4213
4214        if (start_pfn < end_pfn)
4215            free_bootmem_node(NODE_DATA(this_nid),
4216                      PFN_PHYS(start_pfn),
4217                      (end_pfn - start_pfn) << PAGE_SHIFT);
4218    }
4219}
4220
4221/**
4222 * sparse_memory_present_with_active_regions - Call memory_present for each active range
4223 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
4224 *
4225 * If an architecture guarantees that all ranges registered with
4226 * add_active_ranges() contain no holes and may be freed, this
4227 * function may be used instead of calling memory_present() manually.
4228 */
4229void __init sparse_memory_present_with_active_regions(int nid)
4230{
4231    unsigned long start_pfn, end_pfn;
4232    int i, this_nid;
4233
4234    for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
4235        memory_present(this_nid, start_pfn, end_pfn);
4236}
4237
4238/**
4239 * get_pfn_range_for_nid - Return the start and end page frames for a node
4240 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
4241 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
4242 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
4243 *
4244 * It returns the start and end page frame of a node based on information
4245 * provided by an arch calling add_active_range(). If called for a node
4246 * with no available memory, a warning is printed and the start and end
4247 * PFNs will be 0.
4248 */
4249void __meminit get_pfn_range_for_nid(unsigned int nid,
4250            unsigned long *start_pfn, unsigned long *end_pfn)
4251{
4252    unsigned long this_start_pfn, this_end_pfn;
4253    int i;
4254
4255    *start_pfn = -1UL;
4256    *end_pfn = 0;
4257
4258    for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
4259        *start_pfn = min(*start_pfn, this_start_pfn);
4260        *end_pfn = max(*end_pfn, this_end_pfn);
4261    }
4262
4263    if (*start_pfn == -1UL)
4264        *start_pfn = 0;
4265}
4266
4267/*
4268 * This finds a zone that can be used for ZONE_MOVABLE pages. The
4269 * assumption is made that zones within a node are ordered in monotonic
4270 * increasing memory addresses so that the "highest" populated zone is used
4271 */
4272static void __init find_usable_zone_for_movable(void)
4273{
4274    int zone_index;
4275    for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
4276        if (zone_index == ZONE_MOVABLE)
4277            continue;
4278
4279        if (arch_zone_highest_possible_pfn[zone_index] >
4280                arch_zone_lowest_possible_pfn[zone_index])
4281            break;
4282    }
4283
4284    VM_BUG_ON(zone_index == -1);
4285    movable_zone = zone_index;
4286}
4287
4288/*
4289 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
4290 * because it is sized independent of architecture. Unlike the other zones,
4291 * the starting point for ZONE_MOVABLE is not fixed. It may be different
4292 * in each node depending on the size of each node and how evenly kernelcore
4293 * is distributed. This helper function adjusts the zone ranges
4294 * provided by the architecture for a given node by using the end of the
4295 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
4296 * zones within a node are in order of monotonic increases memory addresses
4297 */
4298static void __meminit adjust_zone_range_for_zone_movable(int nid,
4299                    unsigned long zone_type,
4300                    unsigned long node_start_pfn,
4301                    unsigned long node_end_pfn,
4302                    unsigned long *zone_start_pfn,
4303                    unsigned long *zone_end_pfn)
4304{
4305    /* Only adjust if ZONE_MOVABLE is on this node */
4306    if (zone_movable_pfn[nid]) {
4307        /* Size ZONE_MOVABLE */
4308        if (zone_type == ZONE_MOVABLE) {
4309            *zone_start_pfn = zone_movable_pfn[nid];
4310            *zone_end_pfn = min(node_end_pfn,
4311                arch_zone_highest_possible_pfn[movable_zone]);
4312
4313        /* Adjust for ZONE_MOVABLE starting within this range */
4314        } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
4315                *zone_end_pfn > zone_movable_pfn[nid]) {
4316            *zone_end_pfn = zone_movable_pfn[nid];
4317
4318        /* Check if this whole range is within ZONE_MOVABLE */
4319        } else if (*zone_start_pfn >= zone_movable_pfn[nid])
4320            *zone_start_pfn = *zone_end_pfn;
4321    }
4322}
4323
4324/*
4325 * Return the number of pages a zone spans in a node, including holes
4326 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
4327 */
4328static unsigned long __meminit zone_spanned_pages_in_node(int nid,
4329                    unsigned long zone_type,
4330                    unsigned long *ignored)
4331{
4332    unsigned long node_start_pfn, node_end_pfn;
4333    unsigned long zone_start_pfn, zone_end_pfn;
4334
4335    /* Get the start and end of the node and zone */
4336    get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
4337    zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
4338    zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
4339    adjust_zone_range_for_zone_movable(nid, zone_type,
4340                node_start_pfn, node_end_pfn,
4341                &zone_start_pfn, &zone_end_pfn);
4342
4343    /* Check that this node has pages within the zone's required range */
4344    if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
4345        return 0;
4346
4347    /* Move the zone boundaries inside the node if necessary */
4348    zone_end_pfn = min(zone_end_pfn, node_end_pfn);
4349    zone_start_pfn = max(zone_start_pfn, node_start_pfn);
4350
4351    /* Return the spanned pages */
4352    return zone_end_pfn - zone_start_pfn;
4353}
4354
4355/*
4356 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
4357 * then all holes in the requested range will be accounted for.
4358 */
4359unsigned long __meminit __absent_pages_in_range(int nid,
4360                unsigned long range_start_pfn,
4361                unsigned long range_end_pfn)
4362{
4363    unsigned long nr_absent = range_end_pfn - range_start_pfn;
4364    unsigned long start_pfn, end_pfn;
4365    int i;
4366
4367    for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
4368        start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
4369        end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
4370        nr_absent -= end_pfn - start_pfn;
4371    }
4372    return nr_absent;
4373}
4374
4375/**
4376 * absent_pages_in_range - Return number of page frames in holes within a range
4377 * @start_pfn: The start PFN to start searching for holes
4378 * @end_pfn: The end PFN to stop searching for holes
4379 *
4380 * It returns the number of pages frames in memory holes within a range.
4381 */
4382unsigned long __init absent_pages_in_range(unsigned long start_pfn,
4383                            unsigned long end_pfn)
4384{
4385    return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
4386}
4387
4388/* Return the number of page frames in holes in a zone on a node */
4389static unsigned long __meminit zone_absent_pages_in_node(int nid,
4390                    unsigned long zone_type,
4391                    unsigned long *ignored)
4392{
4393    unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
4394    unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
4395    unsigned long node_start_pfn, node_end_pfn;
4396    unsigned long zone_start_pfn, zone_end_pfn;
4397
4398    get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
4399    zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
4400    zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
4401
4402    adjust_zone_range_for_zone_movable(nid, zone_type,
4403            node_start_pfn, node_end_pfn,
4404            &zone_start_pfn, &zone_end_pfn);
4405    return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
4406}
4407
4408#else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4409static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
4410                    unsigned long zone_type,
4411                    unsigned long *zones_size)
4412{
4413    return zones_size[zone_type];
4414}
4415
4416static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
4417                        unsigned long zone_type,
4418                        unsigned long *zholes_size)
4419{
4420    if (!zholes_size)
4421        return 0;
4422
4423    return zholes_size[zone_type];
4424}
4425
4426#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4427
4428static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
4429        unsigned long *zones_size, unsigned long *zholes_size)
4430{
4431    unsigned long realtotalpages, totalpages = 0;
4432    enum zone_type i;
4433
4434    for (i = 0; i < MAX_NR_ZONES; i++)
4435        totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
4436                                zones_size);
4437    pgdat->node_spanned_pages = totalpages;
4438
4439    realtotalpages = totalpages;
4440    for (i = 0; i < MAX_NR_ZONES; i++)
4441        realtotalpages -=
4442            zone_absent_pages_in_node(pgdat->node_id, i,
4443                                zholes_size);
4444    pgdat->node_present_pages = realtotalpages;
4445    printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
4446                            realtotalpages);
4447}
4448
4449#ifndef CONFIG_SPARSEMEM
4450/*
4451 * Calculate the size of the zone->blockflags rounded to an unsigned long
4452 * Start by making sure zonesize is a multiple of pageblock_order by rounding
4453 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
4454 * round what is now in bits to nearest long in bits, then return it in
4455 * bytes.
4456 */
4457static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
4458{
4459    unsigned long usemapsize;
4460
4461    zonesize += zone_start_pfn & (pageblock_nr_pages-1);
4462    usemapsize = roundup(zonesize, pageblock_nr_pages);
4463    usemapsize = usemapsize >> pageblock_order;
4464    usemapsize *= NR_PAGEBLOCK_BITS;
4465    usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
4466
4467    return usemapsize / 8;
4468}
4469
4470static void __init setup_usemap(struct pglist_data *pgdat,
4471                struct zone *zone,
4472                unsigned long zone_start_pfn,
4473                unsigned long zonesize)
4474{
4475    unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
4476    zone->pageblock_flags = NULL;
4477    if (usemapsize)
4478        zone->pageblock_flags = alloc_bootmem_node_nopanic(pgdat,
4479                                   usemapsize);
4480}
4481#else
4482static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
4483                unsigned long zone_start_pfn, unsigned long zonesize) {}
4484#endif /* CONFIG_SPARSEMEM */
4485
4486#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
4487
4488/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
4489void __init set_pageblock_order(void)
4490{
4491    unsigned int order;
4492
4493    /* Check that pageblock_nr_pages has not already been setup */
4494    if (pageblock_order)
4495        return;
4496
4497    if (HPAGE_SHIFT > PAGE_SHIFT)
4498        order = HUGETLB_PAGE_ORDER;
4499    else
4500        order = MAX_ORDER - 1;
4501
4502    /*
4503     * Assume the largest contiguous order of interest is a huge page.
4504     * This value may be variable depending on boot parameters on IA64 and
4505     * powerpc.
4506     */
4507    pageblock_order = order;
4508}
4509#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4510
4511/*
4512 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
4513 * is unused as pageblock_order is set at compile-time. See
4514 * include/linux/pageblock-flags.h for the values of pageblock_order based on
4515 * the kernel config
4516 */
4517void __init set_pageblock_order(void)
4518{
4519}
4520
4521#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4522
4523static unsigned long __paginginit calc_memmap_size(unsigned long spanned_pages,
4524                           unsigned long present_pages)
4525{
4526    unsigned long pages = spanned_pages;
4527
4528    /*
4529     * Provide a more accurate estimation if there are holes within
4530     * the zone and SPARSEMEM is in use. If there are holes within the
4531     * zone, each populated memory region may cost us one or two extra
4532     * memmap pages due to alignment because memmap pages for each
4533     * populated regions may not naturally algined on page boundary.
4534     * So the (present_pages >> 4) heuristic is a tradeoff for that.
4535     */
4536    if (spanned_pages > present_pages + (present_pages >> 4) &&
4537        IS_ENABLED(CONFIG_SPARSEMEM))
4538        pages = present_pages;
4539
4540    return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
4541}
4542
4543/*
4544 * Set up the zone data structures:
4545 * - mark all pages reserved
4546 * - mark all memory queues empty
4547 * - clear the memory bitmaps
4548 *
4549 * NOTE: pgdat should get zeroed by caller.
4550 */
4551static void __paginginit free_area_init_core(struct pglist_data *pgdat,
4552        unsigned long *zones_size, unsigned long *zholes_size)
4553{
4554    enum zone_type j;
4555    int nid = pgdat->node_id;
4556    unsigned long zone_start_pfn = pgdat->node_start_pfn;
4557    int ret;
4558
4559    pgdat_resize_init(pgdat);
4560#ifdef CONFIG_NUMA_BALANCING
4561    spin_lock_init(&pgdat->numabalancing_migrate_lock);
4562    pgdat->numabalancing_migrate_nr_pages = 0;
4563    pgdat->numabalancing_migrate_next_window = jiffies;
4564#endif
4565    init_waitqueue_head(&pgdat->kswapd_wait);
4566    init_waitqueue_head(&pgdat->pfmemalloc_wait);
4567    pgdat_page_cgroup_init(pgdat);
4568
4569    for (j = 0; j < MAX_NR_ZONES; j++) {
4570        struct zone *zone = pgdat->node_zones + j;
4571        unsigned long size, realsize, freesize, memmap_pages;
4572
4573        size = zone_spanned_pages_in_node(nid, j, zones_size);
4574        realsize = freesize = size - zone_absent_pages_in_node(nid, j,
4575                                zholes_size);
4576
4577        /*
4578         * Adjust freesize so that it accounts for how much memory
4579         * is used by this zone for memmap. This affects the watermark
4580         * and per-cpu initialisations
4581         */
4582        memmap_pages = calc_memmap_size(size, realsize);
4583        if (freesize >= memmap_pages) {
4584            freesize -= memmap_pages;
4585            if (memmap_pages)
4586                printk(KERN_DEBUG
4587                       " %s zone: %lu pages used for memmap\n",
4588                       zone_names[j], memmap_pages);
4589        } else
4590            printk(KERN_WARNING
4591                " %s zone: %lu pages exceeds freesize %lu\n",
4592                zone_names[j], memmap_pages, freesize);
4593
4594        /* Account for reserved pages */
4595        if (j == 0 && freesize > dma_reserve) {
4596            freesize -= dma_reserve;
4597            printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
4598                    zone_names[0], dma_reserve);
4599        }
4600
4601        if (!is_highmem_idx(j))
4602            nr_kernel_pages += freesize;
4603        /* Charge for highmem memmap if there are enough kernel pages */
4604        else if (nr_kernel_pages > memmap_pages * 2)
4605            nr_kernel_pages -= memmap_pages;
4606        nr_all_pages += freesize;
4607
4608        zone->spanned_pages = size;
4609        zone->present_pages = realsize;
4610        /*
4611         * Set an approximate value for lowmem here, it will be adjusted
4612         * when the bootmem allocator frees pages into the buddy system.
4613         * And all highmem pages will be managed by the buddy system.
4614         */
4615        zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
4616#ifdef CONFIG_NUMA
4617        zone->node = nid;
4618        zone->min_unmapped_pages = (freesize*sysctl_min_unmapped_ratio)
4619                        / 100;
4620        zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100;
4621#endif
4622        zone->name = zone_names[j];
4623        spin_lock_init(&zone->lock);
4624        spin_lock_init(&zone->lru_lock);
4625        zone_seqlock_init(zone);
4626        zone->zone_pgdat = pgdat;
4627
4628        zone_pcp_init(zone);
4629        lruvec_init(&zone->lruvec);
4630        if (!size)
4631            continue;
4632
4633        set_pageblock_order();
4634        setup_usemap(pgdat, zone, zone_start_pfn, size);
4635        ret = init_currently_empty_zone(zone, zone_start_pfn,
4636                        size, MEMMAP_EARLY);
4637        BUG_ON(ret);
4638        memmap_init(size, nid, j, zone_start_pfn);
4639        zone_start_pfn += size;
4640    }
4641}
4642
4643static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
4644{
4645    /* Skip empty nodes */
4646    if (!pgdat->node_spanned_pages)
4647        return;
4648
4649#ifdef CONFIG_FLAT_NODE_MEM_MAP
4650    /* ia64 gets its own node_mem_map, before this, without bootmem */
4651    if (!pgdat->node_mem_map) {
4652        unsigned long size, start, end;
4653        struct page *map;
4654
4655        /*
4656         * The zone's endpoints aren't required to be MAX_ORDER
4657         * aligned but the node_mem_map endpoints must be in order
4658         * for the buddy allocator to function correctly.
4659         */
4660        start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
4661        end = pgdat_end_pfn(pgdat);
4662        end = ALIGN(end, MAX_ORDER_NR_PAGES);
4663        size = (end - start) * sizeof(struct page);
4664        map = alloc_remap(pgdat->node_id, size);
4665        if (!map)
4666            map = alloc_bootmem_node_nopanic(pgdat, size);
4667        pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
4668    }
4669#ifndef CONFIG_NEED_MULTIPLE_NODES
4670    /*
4671     * With no DISCONTIG, the global mem_map is just set as node 0's
4672     */
4673    if (pgdat == NODE_DATA(0)) {
4674        mem_map = NODE_DATA(0)->node_mem_map;
4675#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4676        if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
4677            mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
4678#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4679    }
4680#endif
4681#endif /* CONFIG_FLAT_NODE_MEM_MAP */
4682}
4683
4684void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
4685        unsigned long node_start_pfn, unsigned long *zholes_size)
4686{
4687    pg_data_t *pgdat = NODE_DATA(nid);
4688
4689    /* pg_data_t should be reset to zero when it's allocated */
4690    WARN_ON(pgdat->nr_zones || pgdat->classzone_idx);
4691
4692    pgdat->node_id = nid;
4693    pgdat->node_start_pfn = node_start_pfn;
4694    init_zone_allows_reclaim(nid);
4695    calculate_node_totalpages(pgdat, zones_size, zholes_size);
4696
4697    alloc_node_mem_map(pgdat);
4698#ifdef CONFIG_FLAT_NODE_MEM_MAP
4699    printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
4700        nid, (unsigned long)pgdat,
4701        (unsigned long)pgdat->node_mem_map);
4702#endif
4703
4704    free_area_init_core(pgdat, zones_size, zholes_size);
4705}
4706
4707#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4708
4709#if MAX_NUMNODES > 1
4710/*
4711 * Figure out the number of possible node ids.
4712 */
4713static void __init setup_nr_node_ids(void)
4714{
4715    unsigned int node;
4716    unsigned int highest = 0;
4717
4718    for_each_node_mask(node, node_possible_map)
4719        highest = node;
4720    nr_node_ids = highest + 1;
4721}
4722#else
4723static inline void setup_nr_node_ids(void)
4724{
4725}
4726#endif
4727
4728/**
4729 * node_map_pfn_alignment - determine the maximum internode alignment
4730 *
4731 * This function should be called after node map is populated and sorted.
4732 * It calculates the maximum power of two alignment which can distinguish
4733 * all the nodes.
4734 *
4735 * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
4736 * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)). If the
4737 * nodes are shifted by 256MiB, 256MiB. Note that if only the last node is
4738 * shifted, 1GiB is enough and this function will indicate so.
4739 *
4740 * This is used to test whether pfn -> nid mapping of the chosen memory
4741 * model has fine enough granularity to avoid incorrect mapping for the
4742 * populated node map.
4743 *
4744 * Returns the determined alignment in pfn's. 0 if there is no alignment
4745 * requirement (single node).
4746 */
4747unsigned long __init node_map_pfn_alignment(void)
4748{
4749    unsigned long accl_mask = 0, last_end = 0;
4750    unsigned long start, end, mask;
4751    int last_nid = -1;
4752    int i, nid;
4753
4754    for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
4755        if (!start || last_nid < 0 || last_nid == nid) {
4756            last_nid = nid;
4757            last_end = end;
4758            continue;
4759        }
4760
4761        /*
4762         * Start with a mask granular enough to pin-point to the
4763         * start pfn and tick off bits one-by-one until it becomes
4764         * too coarse to separate the current node from the last.
4765         */
4766        mask = ~((1 << __ffs(start)) - 1);
4767        while (mask && last_end <= (start & (mask << 1)))
4768            mask <<= 1;
4769
4770        /* accumulate all internode masks */
4771        accl_mask |= mask;
4772    }
4773
4774    /* convert mask to number of pages */
4775    return ~accl_mask + 1;
4776}
4777
4778/* Find the lowest pfn for a node */
4779static unsigned long __init find_min_pfn_for_node(int nid)
4780{
4781    unsigned long min_pfn = ULONG_MAX;
4782    unsigned long start_pfn;
4783    int i;
4784
4785    for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
4786        min_pfn = min(min_pfn, start_pfn);
4787
4788    if (min_pfn == ULONG_MAX) {
4789        printk(KERN_WARNING
4790            "Could not find start_pfn for node %d\n", nid);
4791        return 0;
4792    }
4793
4794    return min_pfn;
4795}
4796
4797/**
4798 * find_min_pfn_with_active_regions - Find the minimum PFN registered
4799 *
4800 * It returns the minimum PFN based on information provided via
4801 * add_active_range().
4802 */
4803unsigned long __init find_min_pfn_with_active_regions(void)
4804{
4805    return find_min_pfn_for_node(MAX_NUMNODES);
4806}
4807
4808/*
4809 * early_calculate_totalpages()
4810 * Sum pages in active regions for movable zone.
4811 * Populate N_MEMORY for calculating usable_nodes.
4812 */
4813static unsigned long __init early_calculate_totalpages(void)
4814{
4815    unsigned long totalpages = 0;
4816    unsigned long start_pfn, end_pfn;
4817    int i, nid;
4818
4819    for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
4820        unsigned long pages = end_pfn - start_pfn;
4821
4822        totalpages += pages;
4823        if (pages)
4824            node_set_state(nid, N_MEMORY);
4825    }
4826      return totalpages;
4827}
4828
4829/*
4830 * Find the PFN the Movable zone begins in each node. Kernel memory
4831 * is spread evenly between nodes as long as the nodes have enough
4832 * memory. When they don't, some nodes will have more kernelcore than
4833 * others
4834 */
4835static void __init find_zone_movable_pfns_for_nodes(void)
4836{
4837    int i, nid;
4838    unsigned long usable_startpfn;
4839    unsigned long kernelcore_node, kernelcore_remaining;
4840    /* save the state before borrow the nodemask */
4841    nodemask_t saved_node_state = node_states[N_MEMORY];
4842    unsigned long totalpages = early_calculate_totalpages();
4843    int usable_nodes = nodes_weight(node_states[N_MEMORY]);
4844
4845    /*
4846     * If movablecore was specified, calculate what size of
4847     * kernelcore that corresponds so that memory usable for
4848     * any allocation type is evenly spread. If both kernelcore
4849     * and movablecore are specified, then the value of kernelcore
4850     * will be used for required_kernelcore if it's greater than
4851     * what movablecore would have allowed.
4852     */
4853    if (required_movablecore) {
4854        unsigned long corepages;
4855
4856        /*
4857         * Round-up so that ZONE_MOVABLE is at least as large as what
4858         * was requested by the user
4859         */
4860        required_movablecore =
4861            roundup(required_movablecore, MAX_ORDER_NR_PAGES);
4862        corepages = totalpages - required_movablecore;
4863
4864        required_kernelcore = max(required_kernelcore, corepages);
4865    }
4866
4867    /* If kernelcore was not specified, there is no ZONE_MOVABLE */
4868    if (!required_kernelcore)
4869        goto out;
4870
4871    /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
4872    find_usable_zone_for_movable();
4873    usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
4874
4875restart:
4876    /* Spread kernelcore memory as evenly as possible throughout nodes */
4877    kernelcore_node = required_kernelcore / usable_nodes;
4878    for_each_node_state(nid, N_MEMORY) {
4879        unsigned long start_pfn, end_pfn;
4880
4881        /*
4882         * Recalculate kernelcore_node if the division per node
4883         * now exceeds what is necessary to satisfy the requested
4884         * amount of memory for the kernel
4885         */
4886        if (required_kernelcore < kernelcore_node)
4887            kernelcore_node = required_kernelcore / usable_nodes;
4888
4889        /*
4890         * As the map is walked, we track how much memory is usable
4891         * by the kernel using kernelcore_remaining. When it is
4892         * 0, the rest of the node is usable by ZONE_MOVABLE
4893         */
4894        kernelcore_remaining = kernelcore_node;
4895
4896        /* Go through each range of PFNs within this node */
4897        for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
4898            unsigned long size_pages;
4899
4900            start_pfn = max(start_pfn, zone_movable_pfn[nid]);
4901            if (start_pfn >= end_pfn)
4902                continue;
4903
4904            /* Account for what is only usable for kernelcore */
4905            if (start_pfn < usable_startpfn) {
4906                unsigned long kernel_pages;
4907                kernel_pages = min(end_pfn, usable_startpfn)
4908                                - start_pfn;
4909
4910                kernelcore_remaining -= min(kernel_pages,
4911                            kernelcore_remaining);
4912                required_kernelcore -= min(kernel_pages,
4913                            required_kernelcore);
4914
4915                /* Continue if range is now fully accounted */
4916                if (end_pfn <= usable_startpfn) {
4917
4918                    /*
4919                     * Push zone_movable_pfn to the end so
4920                     * that if we have to rebalance
4921                     * kernelcore across nodes, we will
4922                     * not double account here
4923                     */
4924                    zone_movable_pfn[nid] = end_pfn;
4925                    continue;
4926                }
4927                start_pfn = usable_startpfn;
4928            }
4929
4930            /*
4931             * The usable PFN range for ZONE_MOVABLE is from
4932             * start_pfn->end_pfn. Calculate size_pages as the
4933             * number of pages used as kernelcore
4934             */
4935            size_pages = end_pfn - start_pfn;
4936            if (size_pages > kernelcore_remaining)
4937                size_pages = kernelcore_remaining;
4938            zone_movable_pfn[nid] = start_pfn + size_pages;
4939
4940            /*
4941             * Some kernelcore has been met, update counts and
4942             * break if the kernelcore for this node has been
4943             * satisified
4944             */
4945            required_kernelcore -= min(required_kernelcore,
4946                                size_pages);
4947            kernelcore_remaining -= size_pages;
4948            if (!kernelcore_remaining)
4949                break;
4950        }
4951    }
4952
4953    /*
4954     * If there is still required_kernelcore, we do another pass with one
4955     * less node in the count. This will push zone_movable_pfn[nid] further
4956     * along on the nodes that still have memory until kernelcore is
4957     * satisified
4958     */
4959    usable_nodes--;
4960    if (usable_nodes && required_kernelcore > usable_nodes)
4961        goto restart;
4962
4963    /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
4964    for (nid = 0; nid < MAX_NUMNODES; nid++)
4965        zone_movable_pfn[nid] =
4966            roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
4967
4968out:
4969    /* restore the node_state */
4970    node_states[N_MEMORY] = saved_node_state;
4971}
4972
4973/* Any regular or high memory on that node ? */
4974static void check_for_memory(pg_data_t *pgdat, int nid)
4975{
4976    enum zone_type zone_type;
4977
4978    if (N_MEMORY == N_NORMAL_MEMORY)
4979        return;
4980
4981    for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
4982        struct zone *zone = &pgdat->node_zones[zone_type];
4983        if (zone->present_pages) {
4984            node_set_state(nid, N_HIGH_MEMORY);
4985            if (N_NORMAL_MEMORY != N_HIGH_MEMORY &&
4986                zone_type <= ZONE_NORMAL)
4987                node_set_state(nid, N_NORMAL_MEMORY);
4988            break;
4989        }
4990    }
4991}
4992
4993/**
4994 * free_area_init_nodes - Initialise all pg_data_t and zone data
4995 * @max_zone_pfn: an array of max PFNs for each zone
4996 *
4997 * This will call free_area_init_node() for each active node in the system.
4998 * Using the page ranges provided by add_active_range(), the size of each
4999 * zone in each node and their holes is calculated. If the maximum PFN
5000 * between two adjacent zones match, it is assumed that the zone is empty.
5001 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
5002 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
5003 * starts where the previous one ended. For example, ZONE_DMA32 starts
5004 * at arch_max_dma_pfn.
5005 */
5006void __init free_area_init_nodes(unsigned long *max_zone_pfn)
5007{
5008    unsigned long start_pfn, end_pfn;
5009    int i, nid;
5010
5011    /* Record where the zone boundaries are */
5012    memset(arch_zone_lowest_possible_pfn, 0,
5013                sizeof(arch_zone_lowest_possible_pfn));
5014    memset(arch_zone_highest_possible_pfn, 0,
5015                sizeof(arch_zone_highest_possible_pfn));
5016    arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
5017    arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
5018    for (i = 1; i < MAX_NR_ZONES; i++) {
5019        if (i == ZONE_MOVABLE)
5020            continue;
5021        arch_zone_lowest_possible_pfn[i] =
5022            arch_zone_highest_possible_pfn[i-1];
5023        arch_zone_highest_possible_pfn[i] =
5024            max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
5025    }
5026    arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
5027    arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
5028
5029    /* Find the PFNs that ZONE_MOVABLE begins at in each node */
5030    memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
5031    find_zone_movable_pfns_for_nodes();
5032
5033    /* Print out the zone ranges */
5034    printk("Zone ranges:\n");
5035    for (i = 0; i < MAX_NR_ZONES; i++) {
5036        if (i == ZONE_MOVABLE)
5037            continue;
5038        printk(KERN_CONT " %-8s ", zone_names[i]);
5039        if (arch_zone_lowest_possible_pfn[i] ==
5040                arch_zone_highest_possible_pfn[i])
5041            printk(KERN_CONT "empty\n");
5042        else
5043            printk(KERN_CONT "[mem %0#10lx-%0#10lx]\n",
5044                arch_zone_lowest_possible_pfn[i] << PAGE_SHIFT,
5045                (arch_zone_highest_possible_pfn[i]
5046                    << PAGE_SHIFT) - 1);
5047    }
5048
5049    /* Print out the PFNs ZONE_MOVABLE begins at in each node */
5050    printk("Movable zone start for each node\n");
5051    for (i = 0; i < MAX_NUMNODES; i++) {
5052        if (zone_movable_pfn[i])
5053            printk(" Node %d: %#010lx\n", i,
5054                   zone_movable_pfn[i] << PAGE_SHIFT);
5055    }
5056
5057    /* Print out the early node map */
5058    printk("Early memory node ranges\n");
5059    for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
5060        printk(" node %3d: [mem %#010lx-%#010lx]\n", nid,
5061               start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1);
5062
5063    /* Initialise every node */
5064    mminit_verify_pageflags_layout();
5065    setup_nr_node_ids();
5066    for_each_online_node(nid) {
5067        pg_data_t *pgdat = NODE_DATA(nid);
5068        free_area_init_node(nid, NULL,
5069                find_min_pfn_for_node(nid), NULL);
5070
5071        /* Any memory on that node */
5072        if (pgdat->node_present_pages)
5073            node_set_state(nid, N_MEMORY);
5074        check_for_memory(pgdat, nid);
5075    }
5076}
5077
5078static int __init cmdline_parse_core(char *p, unsigned long *core)
5079{
5080    unsigned long long coremem;
5081    if (!p)
5082        return -EINVAL;
5083
5084    coremem = memparse(p, &p);
5085    *core = coremem >> PAGE_SHIFT;
5086
5087    /* Paranoid check that UL is enough for the coremem value */
5088    WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
5089
5090    return 0;
5091}
5092
5093/*
5094 * kernelcore=size sets the amount of memory for use for allocations that
5095 * cannot be reclaimed or migrated.
5096 */
5097static int __init cmdline_parse_kernelcore(char *p)
5098{
5099    return cmdline_parse_core(p, &required_kernelcore);
5100}
5101
5102/*
5103 * movablecore=size sets the amount of memory for use for allocations that
5104 * can be reclaimed or migrated.
5105 */
5106static int __init cmdline_parse_movablecore(char *p)
5107{
5108    return cmdline_parse_core(p, &required_movablecore);
5109}
5110
5111early_param("kernelcore", cmdline_parse_kernelcore);
5112early_param("movablecore", cmdline_parse_movablecore);
5113
5114#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5115
5116/**
5117 * set_dma_reserve - set the specified number of pages reserved in the first zone
5118 * @new_dma_reserve: The number of pages to mark reserved
5119 *
5120 * The per-cpu batchsize and zone watermarks are determined by present_pages.
5121 * In the DMA zone, a significant percentage may be consumed by kernel image
5122 * and other unfreeable allocations which can skew the watermarks badly. This
5123 * function may optionally be used to account for unfreeable pages in the
5124 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
5125 * smaller per-cpu batchsize.
5126 */
5127void __init set_dma_reserve(unsigned long new_dma_reserve)
5128{
5129    dma_reserve = new_dma_reserve;
5130}
5131
5132void __init free_area_init(unsigned long *zones_size)
5133{
5134    free_area_init_node(0, zones_size,
5135            __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
5136}
5137
5138static int page_alloc_cpu_notify(struct notifier_block *self,
5139                 unsigned long action, void *hcpu)
5140{
5141    int cpu = (unsigned long)hcpu;
5142
5143    if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
5144        lru_add_drain_cpu(cpu);
5145        drain_pages(cpu);
5146
5147        /*
5148         * Spill the event counters of the dead processor
5149         * into the current processors event counters.
5150         * This artificially elevates the count of the current
5151         * processor.
5152         */
5153        vm_events_fold_cpu(cpu);
5154
5155        /*
5156         * Zero the differential counters of the dead processor
5157         * so that the vm statistics are consistent.
5158         *
5159         * This is only okay since the processor is dead and cannot
5160         * race with what we are doing.
5161         */
5162        refresh_cpu_vm_stats(cpu);
5163    }
5164    return NOTIFY_OK;
5165}
5166
5167void __init page_alloc_init(void)
5168{
5169    hotcpu_notifier(page_alloc_cpu_notify, 0);
5170}
5171
5172/*
5173 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
5174 * or min_free_kbytes changes.
5175 */
5176static void calculate_totalreserve_pages(void)
5177{
5178    struct pglist_data *pgdat;
5179    unsigned long reserve_pages = 0;
5180    enum zone_type i, j;
5181
5182    for_each_online_pgdat(pgdat) {
5183        for (i = 0; i < MAX_NR_ZONES; i++) {
5184            struct zone *zone = pgdat->node_zones + i;
5185            unsigned long max = 0;
5186
5187            /* Find valid and maximum lowmem_reserve in the zone */
5188            for (j = i; j < MAX_NR_ZONES; j++) {
5189                if (zone->lowmem_reserve[j] > max)
5190                    max = zone->lowmem_reserve[j];
5191            }
5192
5193            /* we treat the high watermark as reserved pages. */
5194            max += high_wmark_pages(zone);
5195
5196            if (max > zone->managed_pages)
5197                max = zone->managed_pages;
5198            reserve_pages += max;
5199            /*
5200             * Lowmem reserves are not available to
5201             * GFP_HIGHUSER page cache allocations and
5202             * kswapd tries to balance zones to their high
5203             * watermark. As a result, neither should be
5204             * regarded as dirtyable memory, to prevent a
5205             * situation where reclaim has to clean pages
5206             * in order to balance the zones.
5207             */
5208            zone->dirty_balance_reserve = max;
5209        }
5210    }
5211    dirty_balance_reserve = reserve_pages;
5212    totalreserve_pages = reserve_pages;
5213}
5214
5215/*
5216 * setup_per_zone_lowmem_reserve - called whenever
5217 * sysctl_lower_zone_reserve_ratio changes. Ensures that each zone
5218 * has a correct pages reserved value, so an adequate number of
5219 * pages are left in the zone after a successful __alloc_pages().
5220 */
5221static void setup_per_zone_lowmem_reserve(void)
5222{
5223    struct pglist_data *pgdat;
5224    enum zone_type j, idx;
5225
5226    for_each_online_pgdat(pgdat) {
5227        for (j = 0; j < MAX_NR_ZONES; j++) {
5228            struct zone *zone = pgdat->node_zones + j;
5229            unsigned long managed_pages = zone->managed_pages;
5230
5231            zone->lowmem_reserve[j] = 0;
5232
5233            idx = j;
5234            while (idx) {
5235                struct zone *lower_zone;
5236
5237                idx--;
5238
5239                if (sysctl_lowmem_reserve_ratio[idx] < 1)
5240                    sysctl_lowmem_reserve_ratio[idx] = 1;
5241
5242                lower_zone = pgdat->node_zones + idx;
5243                lower_zone->lowmem_reserve[j] = managed_pages /
5244                    sysctl_lowmem_reserve_ratio[idx];
5245                managed_pages += lower_zone->managed_pages;
5246            }
5247        }
5248    }
5249
5250    /* update totalreserve_pages */
5251    calculate_totalreserve_pages();
5252}
5253
5254static void __setup_per_zone_wmarks(void)
5255{
5256    unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
5257    unsigned long lowmem_pages = 0;
5258    struct zone *zone;
5259    unsigned long flags;
5260
5261    /* Calculate total number of !ZONE_HIGHMEM pages */
5262    for_each_zone(zone) {
5263        if (!is_highmem(zone))
5264            lowmem_pages += zone->managed_pages;
5265    }
5266
5267    for_each_zone(zone) {
5268        u64 tmp;
5269
5270        spin_lock_irqsave(&zone->lock, flags);
5271        tmp = (u64)pages_min * zone->managed_pages;
5272        do_div(tmp, lowmem_pages);
5273        if (is_highmem(zone)) {
5274            /*
5275             * __GFP_HIGH and PF_MEMALLOC allocations usually don't
5276             * need highmem pages, so cap pages_min to a small
5277             * value here.
5278             *
5279             * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
5280             * deltas controls asynch page reclaim, and so should
5281             * not be capped for highmem.
5282             */
5283            unsigned long min_pages;
5284
5285            min_pages = zone->managed_pages / 1024;
5286            min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
5287            zone->watermark[WMARK_MIN] = min_pages;
5288        } else {
5289            /*
5290             * If it's a lowmem zone, reserve a number of pages
5291             * proportionate to the zone's size.
5292             */
5293            zone->watermark[WMARK_MIN] = tmp;
5294        }
5295
5296        zone->watermark[WMARK_LOW] = min_wmark_pages(zone) + (tmp >> 2);
5297        zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
5298
5299        setup_zone_migrate_reserve(zone);
5300        spin_unlock_irqrestore(&zone->lock, flags);
5301    }
5302
5303    /* update totalreserve_pages */
5304    calculate_totalreserve_pages();
5305}
5306
5307/**
5308 * setup_per_zone_wmarks - called when min_free_kbytes changes
5309 * or when memory is hot-{added|removed}
5310 *
5311 * Ensures that the watermark[min,low,high] values for each zone are set
5312 * correctly with respect to min_free_kbytes.
5313 */
5314void setup_per_zone_wmarks(void)
5315{
5316    mutex_lock(&zonelists_mutex);
5317    __setup_per_zone_wmarks();
5318    mutex_unlock(&zonelists_mutex);
5319}
5320
5321/*
5322 * The inactive anon list should be small enough that the VM never has to
5323 * do too much work, but large enough that each inactive page has a chance
5324 * to be referenced again before it is swapped out.
5325 *
5326 * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
5327 * INACTIVE_ANON pages on this zone's LRU, maintained by the
5328 * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
5329 * the anonymous pages are kept on the inactive list.
5330 *
5331 * total target max
5332 * memory ratio inactive anon
5333 * -------------------------------------
5334 * 10MB 1 5MB
5335 * 100MB 1 50MB
5336 * 1GB 3 250MB
5337 * 10GB 10 0.9GB
5338 * 100GB 31 3GB
5339 * 1TB 101 10GB
5340 * 10TB 320 32GB
5341 */
5342static void __meminit calculate_zone_inactive_ratio(struct zone *zone)
5343{
5344    unsigned int gb, ratio;
5345
5346    /* Zone size in gigabytes */
5347    gb = zone->managed_pages >> (30 - PAGE_SHIFT);
5348    if (gb)
5349        ratio = int_sqrt(10 * gb);
5350    else
5351        ratio = 1;
5352
5353    zone->inactive_ratio = ratio;
5354}
5355
5356static void __meminit setup_per_zone_inactive_ratio(void)
5357{
5358    struct zone *zone;
5359
5360    for_each_zone(zone)
5361        calculate_zone_inactive_ratio(zone);
5362}
5363
5364/*
5365 * Initialise min_free_kbytes.
5366 *
5367 * For small machines we want it small (128k min). For large machines
5368 * we want it large (64MB max). But it is not linear, because network
5369 * bandwidth does not increase linearly with machine size. We use
5370 *
5371 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
5372 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
5373 *
5374 * which yields
5375 *
5376 * 16MB: 512k
5377 * 32MB: 724k
5378 * 64MB: 1024k
5379 * 128MB: 1448k
5380 * 256MB: 2048k
5381 * 512MB: 2896k
5382 * 1024MB: 4096k
5383 * 2048MB: 5792k
5384 * 4096MB: 8192k
5385 * 8192MB: 11584k
5386 * 16384MB: 16384k
5387 */
5388int __meminit init_per_zone_wmark_min(void)
5389{
5390    unsigned long lowmem_kbytes;
5391
5392    lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
5393
5394    min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
5395    if (min_free_kbytes < 128)
5396        min_free_kbytes = 128;
5397    if (min_free_kbytes > 65536)
5398        min_free_kbytes = 65536;
5399    setup_per_zone_wmarks();
5400    refresh_zone_stat_thresholds();
5401    setup_per_zone_lowmem_reserve();
5402    setup_per_zone_inactive_ratio();
5403    return 0;
5404}
5405module_init(init_per_zone_wmark_min)
5406
5407/*
5408 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
5409 * that we can call two helper functions whenever min_free_kbytes
5410 * changes.
5411 */
5412int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
5413    void __user *buffer, size_t *length, loff_t *ppos)
5414{
5415    proc_dointvec(table, write, buffer, length, ppos);
5416    if (write)
5417        setup_per_zone_wmarks();
5418    return 0;
5419}
5420
5421#ifdef CONFIG_NUMA
5422int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
5423    void __user *buffer, size_t *length, loff_t *ppos)
5424{
5425    struct zone *zone;
5426    int rc;
5427
5428    rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5429    if (rc)
5430        return rc;
5431
5432    for_each_zone(zone)
5433        zone->min_unmapped_pages = (zone->managed_pages *
5434                sysctl_min_unmapped_ratio) / 100;
5435    return 0;
5436}
5437
5438int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
5439    void __user *buffer, size_t *length, loff_t *ppos)
5440{
5441    struct zone *zone;
5442    int rc;
5443
5444    rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5445    if (rc)
5446        return rc;
5447
5448    for_each_zone(zone)
5449        zone->min_slab_pages = (zone->managed_pages *
5450                sysctl_min_slab_ratio) / 100;
5451    return 0;
5452}
5453#endif
5454
5455/*
5456 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
5457 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
5458 * whenever sysctl_lowmem_reserve_ratio changes.
5459 *
5460 * The reserve ratio obviously has absolutely no relation with the
5461 * minimum watermarks. The lowmem reserve ratio can only make sense
5462 * if in function of the boot time zone sizes.
5463 */
5464int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
5465    void __user *buffer, size_t *length, loff_t *ppos)
5466{
5467    proc_dointvec_minmax(table, write, buffer, length, ppos);
5468    setup_per_zone_lowmem_reserve();
5469    return 0;
5470}
5471
5472/*
5473 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
5474 * cpu. It is the fraction of total pages in each zone that a hot per cpu pagelist
5475 * can have before it gets flushed back to buddy allocator.
5476 */
5477
5478int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
5479    void __user *buffer, size_t *length, loff_t *ppos)
5480{
5481    struct zone *zone;
5482    unsigned int cpu;
5483    int ret;
5484
5485    ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
5486    if (!write || (ret < 0))
5487        return ret;
5488    for_each_populated_zone(zone) {
5489        for_each_possible_cpu(cpu) {
5490            unsigned long high;
5491            high = zone->managed_pages / percpu_pagelist_fraction;
5492            setup_pagelist_highmark(
5493                per_cpu_ptr(zone->pageset, cpu), high);
5494        }
5495    }
5496    return 0;
5497}
5498
5499int hashdist = HASHDIST_DEFAULT;
5500
5501#ifdef CONFIG_NUMA
5502static int __init set_hashdist(char *str)
5503{
5504    if (!str)
5505        return 0;
5506    hashdist = simple_strtoul(str, &str, 0);
5507    return 1;
5508}
5509__setup("hashdist=", set_hashdist);
5510#endif
5511
5512/*
5513 * allocate a large system hash table from bootmem
5514 * - it is assumed that the hash table must contain an exact power-of-2
5515 * quantity of entries
5516 * - limit is the number of hash buckets, not the total allocation size
5517 */
5518void *__init alloc_large_system_hash(const char *tablename,
5519                     unsigned long bucketsize,
5520                     unsigned long numentries,
5521                     int scale,
5522                     int flags,
5523                     unsigned int *_hash_shift,
5524                     unsigned int *_hash_mask,
5525                     unsigned long low_limit,
5526                     unsigned long high_limit)
5527{
5528    unsigned long long max = high_limit;
5529    unsigned long log2qty, size;
5530    void *table = NULL;
5531
5532    /* allow the kernel cmdline to have a say */
5533    if (!numentries) {
5534        /* round applicable memory size up to nearest megabyte */
5535        numentries = nr_kernel_pages;
5536        numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
5537        numentries >>= 20 - PAGE_SHIFT;
5538        numentries <<= 20 - PAGE_SHIFT;
5539
5540        /* limit to 1 bucket per 2^scale bytes of low memory */
5541        if (scale > PAGE_SHIFT)
5542            numentries >>= (scale - PAGE_SHIFT);
5543        else
5544            numentries <<= (PAGE_SHIFT - scale);
5545
5546        /* Make sure we've got at least a 0-order allocation.. */
5547        if (unlikely(flags & HASH_SMALL)) {
5548            /* Makes no sense without HASH_EARLY */
5549            WARN_ON(!(flags & HASH_EARLY));
5550            if (!(numentries >> *_hash_shift)) {
5551                numentries = 1UL << *_hash_shift;
5552                BUG_ON(!numentries);
5553            }
5554        } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
5555            numentries = PAGE_SIZE / bucketsize;
5556    }
5557    numentries = roundup_pow_of_two(numentries);
5558
5559    /* limit allocation size to 1/16 total memory by default */
5560    if (max == 0) {
5561        max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
5562        do_div(max, bucketsize);
5563    }
5564    max = min(max, 0x80000000ULL);
5565
5566    if (numentries < low_limit)
5567        numentries = low_limit;
5568    if (numentries > max)
5569        numentries = max;
5570
5571    log2qty = ilog2(numentries);
5572
5573    do {
5574        size = bucketsize << log2qty;
5575        if (flags & HASH_EARLY)
5576            table = alloc_bootmem_nopanic(size);
5577        else if (hashdist)
5578            table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
5579        else {
5580            /*
5581             * If bucketsize is not a power-of-two, we may free
5582             * some pages at the end of hash table which
5583             * alloc_pages_exact() automatically does
5584             */
5585            if (get_order(size) < MAX_ORDER) {
5586                table = alloc_pages_exact(size, GFP_ATOMIC);
5587                kmemleak_alloc(table, size, 1, GFP_ATOMIC);
5588            }
5589        }
5590    } while (!table && size > PAGE_SIZE && --log2qty);
5591
5592    if (!table)
5593        panic("Failed to allocate %s hash table\n", tablename);
5594
5595    printk(KERN_INFO "%s hash table entries: %ld (order: %d, %lu bytes)\n",
5596           tablename,
5597           (1UL << log2qty),
5598           ilog2(size) - PAGE_SHIFT,
5599           size);
5600
5601    if (_hash_shift)
5602        *_hash_shift = log2qty;
5603    if (_hash_mask)
5604        *_hash_mask = (1 << log2qty) - 1;
5605
5606    return table;
5607}
5608
5609/* Return a pointer to the bitmap storing bits affecting a block of pages */
5610static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
5611                            unsigned long pfn)
5612{
5613#ifdef CONFIG_SPARSEMEM
5614    return __pfn_to_section(pfn)->pageblock_flags;
5615#else
5616    return zone->pageblock_flags;
5617#endif /* CONFIG_SPARSEMEM */
5618}
5619
5620static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
5621{
5622#ifdef CONFIG_SPARSEMEM
5623    pfn &= (PAGES_PER_SECTION-1);
5624    return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5625#else
5626    pfn = pfn - round_down(zone->zone_start_pfn, pageblock_nr_pages);
5627    return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5628#endif /* CONFIG_SPARSEMEM */
5629}
5630
5631/**
5632 * get_pageblock_flags_group - Return the requested group of flags for the pageblock_nr_pages block of pages
5633 * @page: The page within the block of interest
5634 * @start_bitidx: The first bit of interest to retrieve
5635 * @end_bitidx: The last bit of interest
5636 * returns pageblock_bits flags
5637 */
5638unsigned long get_pageblock_flags_group(struct page *page,
5639                    int start_bitidx, int end_bitidx)
5640{
5641    struct zone *zone;
5642    unsigned long *bitmap;
5643    unsigned long pfn, bitidx;
5644    unsigned long flags = 0;
5645    unsigned long value = 1;
5646
5647    zone = page_zone(page);
5648    pfn = page_to_pfn(page);
5649    bitmap = get_pageblock_bitmap(zone, pfn);
5650    bitidx = pfn_to_bitidx(zone, pfn);
5651
5652    for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5653        if (test_bit(bitidx + start_bitidx, bitmap))
5654            flags |= value;
5655
5656    return flags;
5657}
5658
5659/**
5660 * set_pageblock_flags_group - Set the requested group of flags for a pageblock_nr_pages block of pages
5661 * @page: The page within the block of interest
5662 * @start_bitidx: The first bit of interest
5663 * @end_bitidx: The last bit of interest
5664 * @flags: The flags to set
5665 */
5666void set_pageblock_flags_group(struct page *page, unsigned long flags,
5667                    int start_bitidx, int end_bitidx)
5668{
5669    struct zone *zone;
5670    unsigned long *bitmap;
5671    unsigned long pfn, bitidx;
5672    unsigned long value = 1;
5673
5674    zone = page_zone(page);
5675    pfn = page_to_pfn(page);
5676    bitmap = get_pageblock_bitmap(zone, pfn);
5677    bitidx = pfn_to_bitidx(zone, pfn);
5678    VM_BUG_ON(!zone_spans_pfn(zone, pfn));
5679
5680    for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5681        if (flags & value)
5682            __set_bit(bitidx + start_bitidx, bitmap);
5683        else
5684            __clear_bit(bitidx + start_bitidx, bitmap);
5685}
5686
5687/*
5688 * This function checks whether pageblock includes unmovable pages or not.
5689 * If @count is not zero, it is okay to include less @count unmovable pages
5690 *
5691 * PageLRU check wihtout isolation or lru_lock could race so that
5692 * MIGRATE_MOVABLE block might include unmovable pages. It means you can't
5693 * expect this function should be exact.
5694 */
5695bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
5696             bool skip_hwpoisoned_pages)
5697{
5698    unsigned long pfn, iter, found;
5699    int mt;
5700
5701    /*
5702     * For avoiding noise data, lru_add_drain_all() should be called
5703     * If ZONE_MOVABLE, the zone never contains unmovable pages
5704     */
5705    if (zone_idx(zone) == ZONE_MOVABLE)
5706        return false;
5707    mt = get_pageblock_migratetype(page);
5708    if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
5709        return false;
5710
5711    pfn = page_to_pfn(page);
5712    for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
5713        unsigned long check = pfn + iter;
5714
5715        if (!pfn_valid_within(check))
5716            continue;
5717
5718        page = pfn_to_page(check);
5719        /*
5720         * We can't use page_count without pin a page
5721         * because another CPU can free compound page.
5722         * This check already skips compound tails of THP
5723         * because their page->_count is zero at all time.
5724         */
5725        if (!atomic_read(&page->_count)) {
5726            if (PageBuddy(page))
5727                iter += (1 << page_order(page)) - 1;
5728            continue;
5729        }
5730
5731        /*
5732         * The HWPoisoned page may be not in buddy system, and
5733         * page_count() is not 0.
5734         */
5735        if (skip_hwpoisoned_pages && PageHWPoison(page))
5736            continue;
5737
5738        if (!PageLRU(page))
5739            found++;
5740        /*
5741         * If there are RECLAIMABLE pages, we need to check it.
5742         * But now, memory offline itself doesn't call shrink_slab()
5743         * and it still to be fixed.
5744         */
5745        /*
5746         * If the page is not RAM, page_count()should be 0.
5747         * we don't need more check. This is an _used_ not-movable page.
5748         *
5749         * The problematic thing here is PG_reserved pages. PG_reserved
5750         * is set to both of a memory hole page and a _used_ kernel
5751         * page at boot.
5752         */
5753        if (found > count)
5754            return true;
5755    }
5756    return false;
5757}
5758
5759bool is_pageblock_removable_nolock(struct page *page)
5760{
5761    struct zone *zone;
5762    unsigned long pfn;
5763
5764    /*
5765     * We have to be careful here because we are iterating over memory
5766     * sections which are not zone aware so we might end up outside of
5767     * the zone but still within the section.
5768     * We have to take care about the node as well. If the node is offline
5769     * its NODE_DATA will be NULL - see page_zone.
5770     */
5771    if (!node_online(page_to_nid(page)))
5772        return false;
5773
5774    zone = page_zone(page);
5775    pfn = page_to_pfn(page);
5776    if (!zone_spans_pfn(zone, pfn))
5777        return false;
5778
5779    return !has_unmovable_pages(zone, page, 0, true);
5780}
5781
5782#ifdef CONFIG_CMA
5783
5784static unsigned long pfn_max_align_down(unsigned long pfn)
5785{
5786    return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
5787                 pageblock_nr_pages) - 1);
5788}
5789
5790static unsigned long pfn_max_align_up(unsigned long pfn)
5791{
5792    return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
5793                pageblock_nr_pages));
5794}
5795
5796/* [start, end) must belong to a single zone. */
5797static int __alloc_contig_migrate_range(struct compact_control *cc,
5798                    unsigned long start, unsigned long end)
5799{
5800    /* This function is based on compact_zone() from compaction.c. */
5801    unsigned long nr_reclaimed;
5802    unsigned long pfn = start;
5803    unsigned int tries = 0;
5804    int ret = 0;
5805
5806    migrate_prep();
5807
5808    while (pfn < end || !list_empty(&cc->migratepages)) {
5809        if (fatal_signal_pending(current)) {
5810            ret = -EINTR;
5811            break;
5812        }
5813
5814        if (list_empty(&cc->migratepages)) {
5815            cc->nr_migratepages = 0;
5816            pfn = isolate_migratepages_range(cc->zone, cc,
5817                             pfn, end, true);
5818            if (!pfn) {
5819                ret = -EINTR;
5820                break;
5821            }
5822            tries = 0;
5823        } else if (++tries == 5) {
5824            ret = ret < 0 ? ret : -EBUSY;
5825            break;
5826        }
5827
5828        nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
5829