1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/mm/page_alloc.c
5 * Manages the free list, the system allocates free pages here.
6 * Note that kmalloc() lives in slab.c
8 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
9 * Swap reorganised 29.12.95, Stephen Tweedie
10 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
11 * Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
12 * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
13 * Zone balancing, Kanoj Sarcar, SGI, Jan 2000
14 * Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
15 * (lots of bits borrowed from Ingo Molnar & Andrew Morton)
18 #include <linux/stddef.h>
20 #include <linux/highmem.h>
21 #include <linux/swap.h>
22 #include <linux/interrupt.h>
23 #include <linux/pagemap.h>
24 #include <linux/jiffies.h>
25 #include <linux/memblock.h>
26 #include <linux/compiler.h>
27 #include <linux/kernel.h>
28 #include <linux/kasan.h>
29 #include <linux/module.h>
30 #include <linux/suspend.h>
31 #include <linux/pagevec.h>
32 #include <linux/blkdev.h>
33 #include <linux/slab.h>
34 #include <linux/ratelimit.h>
35 #include <linux/oom.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/memremap.h>
46 #include <linux/stop_machine.h>
47 #include <linux/random.h>
48 #include <linux/sort.h>
49 #include <linux/pfn.h>
50 #include <linux/backing-dev.h>
51 #include <linux/fault-inject.h>
52 #include <linux/page-isolation.h>
53 #include <linux/debugobjects.h>
54 #include <linux/kmemleak.h>
55 #include <linux/compaction.h>
56 #include <trace/events/kmem.h>
57 #include <trace/events/oom.h>
58 #include <linux/prefetch.h>
59 #include <linux/mm_inline.h>
60 #include <linux/migrate.h>
61 #include <linux/hugetlb.h>
62 #include <linux/sched/rt.h>
63 #include <linux/sched/mm.h>
64 #include <linux/page_owner.h>
65 #include <linux/kthread.h>
66 #include <linux/memcontrol.h>
67 #include <linux/ftrace.h>
68 #include <linux/lockdep.h>
69 #include <linux/nmi.h>
70 #include <linux/psi.h>
72 #include <asm/sections.h>
73 #include <asm/tlbflush.h>
74 #include <asm/div64.h>
78 /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
79 static DEFINE_MUTEX(pcp_batch_high_lock);
80 #define MIN_PERCPU_PAGELIST_FRACTION (8)
82 #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
83 DEFINE_PER_CPU(int, numa_node);
84 EXPORT_PER_CPU_SYMBOL(numa_node);
87 DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key);
89 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
91 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
92 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
93 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
94 * defined in <linux/topology.h>.
96 DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */
97 EXPORT_PER_CPU_SYMBOL(_numa_mem_);
100 /* work_structs for global per-cpu drains */
103 struct work_struct work;
105 DEFINE_MUTEX(pcpu_drain_mutex);
106 DEFINE_PER_CPU(struct pcpu_drain, pcpu_drain);
108 #ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
109 volatile unsigned long latent_entropy __latent_entropy;
110 EXPORT_SYMBOL(latent_entropy);
114 * Array of node states.
116 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
117 [N_POSSIBLE] = NODE_MASK_ALL,
118 [N_ONLINE] = { { [0] = 1UL } },
120 [N_NORMAL_MEMORY] = { { [0] = 1UL } },
121 #ifdef CONFIG_HIGHMEM
122 [N_HIGH_MEMORY] = { { [0] = 1UL } },
124 [N_MEMORY] = { { [0] = 1UL } },
125 [N_CPU] = { { [0] = 1UL } },
128 EXPORT_SYMBOL(node_states);
130 atomic_long_t _totalram_pages __read_mostly;
131 EXPORT_SYMBOL(_totalram_pages);
132 unsigned long totalreserve_pages __read_mostly;
133 unsigned long totalcma_pages __read_mostly;
135 int percpu_pagelist_fraction;
136 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
137 #ifdef CONFIG_INIT_ON_ALLOC_DEFAULT_ON
138 DEFINE_STATIC_KEY_TRUE(init_on_alloc);
140 DEFINE_STATIC_KEY_FALSE(init_on_alloc);
142 EXPORT_SYMBOL(init_on_alloc);
144 #ifdef CONFIG_INIT_ON_FREE_DEFAULT_ON
145 DEFINE_STATIC_KEY_TRUE(init_on_free);
147 DEFINE_STATIC_KEY_FALSE(init_on_free);
149 EXPORT_SYMBOL(init_on_free);
151 static int __init early_init_on_alloc(char *buf)
158 ret = kstrtobool(buf, &bool_result);
159 if (bool_result && page_poisoning_enabled())
160 pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_alloc\n");
162 static_branch_enable(&init_on_alloc);
164 static_branch_disable(&init_on_alloc);
167 early_param("init_on_alloc", early_init_on_alloc);
169 static int __init early_init_on_free(char *buf)
176 ret = kstrtobool(buf, &bool_result);
177 if (bool_result && page_poisoning_enabled())
178 pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_free\n");
180 static_branch_enable(&init_on_free);
182 static_branch_disable(&init_on_free);
185 early_param("init_on_free", early_init_on_free);
188 * A cached value of the page's pageblock's migratetype, used when the page is
189 * put on a pcplist. Used to avoid the pageblock migratetype lookup when
190 * freeing from pcplists in most cases, at the cost of possibly becoming stale.
191 * Also the migratetype set in the page does not necessarily match the pcplist
192 * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
193 * other index - this ensures that it will be put on the correct CMA freelist.
195 static inline int get_pcppage_migratetype(struct page *page)
200 static inline void set_pcppage_migratetype(struct page *page, int migratetype)
202 page->index = migratetype;
205 #ifdef CONFIG_PM_SLEEP
207 * The following functions are used by the suspend/hibernate code to temporarily
208 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
209 * while devices are suspended. To avoid races with the suspend/hibernate code,
210 * they should always be called with system_transition_mutex held
211 * (gfp_allowed_mask also should only be modified with system_transition_mutex
212 * held, unless the suspend/hibernate code is guaranteed not to run in parallel
213 * with that modification).
216 static gfp_t saved_gfp_mask;
218 void pm_restore_gfp_mask(void)
220 WARN_ON(!mutex_is_locked(&system_transition_mutex));
221 if (saved_gfp_mask) {
222 gfp_allowed_mask = saved_gfp_mask;
227 void pm_restrict_gfp_mask(void)
229 WARN_ON(!mutex_is_locked(&system_transition_mutex));
230 WARN_ON(saved_gfp_mask);
231 saved_gfp_mask = gfp_allowed_mask;
232 gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
235 bool pm_suspended_storage(void)
237 if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS))
241 #endif /* CONFIG_PM_SLEEP */
243 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
244 unsigned int pageblock_order __read_mostly;
247 static void __free_pages_ok(struct page *page, unsigned int order);
250 * results with 256, 32 in the lowmem_reserve sysctl:
251 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
252 * 1G machine -> (16M dma, 784M normal, 224M high)
253 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
254 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
255 * HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA
257 * TBD: should special case ZONE_DMA32 machines here - in those we normally
258 * don't need any ZONE_NORMAL reservation
260 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = {
261 #ifdef CONFIG_ZONE_DMA
264 #ifdef CONFIG_ZONE_DMA32
268 #ifdef CONFIG_HIGHMEM
274 static char * const zone_names[MAX_NR_ZONES] = {
275 #ifdef CONFIG_ZONE_DMA
278 #ifdef CONFIG_ZONE_DMA32
282 #ifdef CONFIG_HIGHMEM
286 #ifdef CONFIG_ZONE_DEVICE
291 const char * const migratetype_names[MIGRATE_TYPES] = {
299 #ifdef CONFIG_MEMORY_ISOLATION
304 compound_page_dtor * const compound_page_dtors[] = {
307 #ifdef CONFIG_HUGETLB_PAGE
310 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
315 int min_free_kbytes = 1024;
316 int user_min_free_kbytes = -1;
317 #ifdef CONFIG_DISCONTIGMEM
319 * DiscontigMem defines memory ranges as separate pg_data_t even if the ranges
320 * are not on separate NUMA nodes. Functionally this works but with
321 * watermark_boost_factor, it can reclaim prematurely as the ranges can be
322 * quite small. By default, do not boost watermarks on discontigmem as in
323 * many cases very high-order allocations like THP are likely to be
324 * unsupported and the premature reclaim offsets the advantage of long-term
325 * fragmentation avoidance.
327 int watermark_boost_factor __read_mostly;
329 int watermark_boost_factor __read_mostly = 15000;
331 int watermark_scale_factor = 10;
333 static unsigned long nr_kernel_pages __initdata;
334 static unsigned long nr_all_pages __initdata;
335 static unsigned long dma_reserve __initdata;
337 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
338 static unsigned long arch_zone_lowest_possible_pfn[MAX_NR_ZONES] __initdata;
339 static unsigned long arch_zone_highest_possible_pfn[MAX_NR_ZONES] __initdata;
340 static unsigned long required_kernelcore __initdata;
341 static unsigned long required_kernelcore_percent __initdata;
342 static unsigned long required_movablecore __initdata;
343 static unsigned long required_movablecore_percent __initdata;
344 static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
345 static bool mirrored_kernelcore __meminitdata;
347 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
349 EXPORT_SYMBOL(movable_zone);
350 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
353 unsigned int nr_node_ids __read_mostly = MAX_NUMNODES;
354 unsigned int nr_online_nodes __read_mostly = 1;
355 EXPORT_SYMBOL(nr_node_ids);
356 EXPORT_SYMBOL(nr_online_nodes);
359 int page_group_by_mobility_disabled __read_mostly;
361 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
363 * During boot we initialize deferred pages on-demand, as needed, but once
364 * page_alloc_init_late() has finished, the deferred pages are all initialized,
365 * and we can permanently disable that path.
367 static DEFINE_STATIC_KEY_TRUE(deferred_pages);
370 * Calling kasan_free_pages() only after deferred memory initialization
371 * has completed. Poisoning pages during deferred memory init will greatly
372 * lengthen the process and cause problem in large memory systems as the
373 * deferred pages initialization is done with interrupt disabled.
375 * Assuming that there will be no reference to those newly initialized
376 * pages before they are ever allocated, this should have no effect on
377 * KASAN memory tracking as the poison will be properly inserted at page
378 * allocation time. The only corner case is when pages are allocated by
379 * on-demand allocation and then freed again before the deferred pages
380 * initialization is done, but this is not likely to happen.
382 static inline void kasan_free_nondeferred_pages(struct page *page, int order)
384 if (!static_branch_unlikely(&deferred_pages))
385 kasan_free_pages(page, order);
388 /* Returns true if the struct page for the pfn is uninitialised */
389 static inline bool __meminit early_page_uninitialised(unsigned long pfn)
391 int nid = early_pfn_to_nid(pfn);
393 if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn)
400 * Returns true when the remaining initialisation should be deferred until
401 * later in the boot cycle when it can be parallelised.
403 static bool __meminit
404 defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
406 static unsigned long prev_end_pfn, nr_initialised;
409 * prev_end_pfn static that contains the end of previous zone
410 * No need to protect because called very early in boot before smp_init.
412 if (prev_end_pfn != end_pfn) {
413 prev_end_pfn = end_pfn;
417 /* Always populate low zones for address-constrained allocations */
418 if (end_pfn < pgdat_end_pfn(NODE_DATA(nid)))
422 * We start only with one section of pages, more pages are added as
423 * needed until the rest of deferred pages are initialized.
426 if ((nr_initialised > PAGES_PER_SECTION) &&
427 (pfn & (PAGES_PER_SECTION - 1)) == 0) {
428 NODE_DATA(nid)->first_deferred_pfn = pfn;
434 #define kasan_free_nondeferred_pages(p, o) kasan_free_pages(p, o)
436 static inline bool early_page_uninitialised(unsigned long pfn)
441 static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
447 /* Return a pointer to the bitmap storing bits affecting a block of pages */
448 static inline unsigned long *get_pageblock_bitmap(struct page *page,
451 #ifdef CONFIG_SPARSEMEM
452 return section_to_usemap(__pfn_to_section(pfn));
454 return page_zone(page)->pageblock_flags;
455 #endif /* CONFIG_SPARSEMEM */
458 static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
460 #ifdef CONFIG_SPARSEMEM
461 pfn &= (PAGES_PER_SECTION-1);
462 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
464 pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
465 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
466 #endif /* CONFIG_SPARSEMEM */
470 * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
471 * @page: The page within the block of interest
472 * @pfn: The target page frame number
473 * @end_bitidx: The last bit of interest to retrieve
474 * @mask: mask of bits that the caller is interested in
476 * Return: pageblock_bits flags
478 static __always_inline unsigned long __get_pfnblock_flags_mask(struct page *page,
480 unsigned long end_bitidx,
483 unsigned long *bitmap;
484 unsigned long bitidx, word_bitidx;
487 bitmap = get_pageblock_bitmap(page, pfn);
488 bitidx = pfn_to_bitidx(page, pfn);
489 word_bitidx = bitidx / BITS_PER_LONG;
490 bitidx &= (BITS_PER_LONG-1);
492 word = bitmap[word_bitidx];
493 bitidx += end_bitidx;
494 return (word >> (BITS_PER_LONG - bitidx - 1)) & mask;
497 unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
498 unsigned long end_bitidx,
501 return __get_pfnblock_flags_mask(page, pfn, end_bitidx, mask);
504 static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
506 return __get_pfnblock_flags_mask(page, pfn, PB_migrate_end, MIGRATETYPE_MASK);
510 * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
511 * @page: The page within the block of interest
512 * @flags: The flags to set
513 * @pfn: The target page frame number
514 * @end_bitidx: The last bit of interest
515 * @mask: mask of bits that the caller is interested in
517 void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
519 unsigned long end_bitidx,
522 unsigned long *bitmap;
523 unsigned long bitidx, word_bitidx;
524 unsigned long old_word, word;
526 BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
527 BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits));
529 bitmap = get_pageblock_bitmap(page, pfn);
530 bitidx = pfn_to_bitidx(page, pfn);
531 word_bitidx = bitidx / BITS_PER_LONG;
532 bitidx &= (BITS_PER_LONG-1);
534 VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
536 bitidx += end_bitidx;
537 mask <<= (BITS_PER_LONG - bitidx - 1);
538 flags <<= (BITS_PER_LONG - bitidx - 1);
540 word = READ_ONCE(bitmap[word_bitidx]);
542 old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags);
543 if (word == old_word)
549 void set_pageblock_migratetype(struct page *page, int migratetype)
551 if (unlikely(page_group_by_mobility_disabled &&
552 migratetype < MIGRATE_PCPTYPES))
553 migratetype = MIGRATE_UNMOVABLE;
555 set_pageblock_flags_group(page, (unsigned long)migratetype,
556 PB_migrate, PB_migrate_end);
559 #ifdef CONFIG_DEBUG_VM
560 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
564 unsigned long pfn = page_to_pfn(page);
565 unsigned long sp, start_pfn;
568 seq = zone_span_seqbegin(zone);
569 start_pfn = zone->zone_start_pfn;
570 sp = zone->spanned_pages;
571 if (!zone_spans_pfn(zone, pfn))
573 } while (zone_span_seqretry(zone, seq));
576 pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
577 pfn, zone_to_nid(zone), zone->name,
578 start_pfn, start_pfn + sp);
583 static int page_is_consistent(struct zone *zone, struct page *page)
585 if (!pfn_valid_within(page_to_pfn(page)))
587 if (zone != page_zone(page))
593 * Temporary debugging check for pages not lying within a given zone.
595 static int __maybe_unused bad_range(struct zone *zone, struct page *page)
597 if (page_outside_zone_boundaries(zone, page))
599 if (!page_is_consistent(zone, page))
605 static inline int __maybe_unused bad_range(struct zone *zone, struct page *page)
611 static void bad_page(struct page *page, const char *reason,
612 unsigned long bad_flags)
614 static unsigned long resume;
615 static unsigned long nr_shown;
616 static unsigned long nr_unshown;
619 * Allow a burst of 60 reports, then keep quiet for that minute;
620 * or allow a steady drip of one report per second.
622 if (nr_shown == 60) {
623 if (time_before(jiffies, resume)) {
629 "BUG: Bad page state: %lu messages suppressed\n",
636 resume = jiffies + 60 * HZ;
638 pr_alert("BUG: Bad page state in process %s pfn:%05lx\n",
639 current->comm, page_to_pfn(page));
640 __dump_page(page, reason);
641 bad_flags &= page->flags;
643 pr_alert("bad because of flags: %#lx(%pGp)\n",
644 bad_flags, &bad_flags);
645 dump_page_owner(page);
650 /* Leave bad fields for debug, except PageBuddy could make trouble */
651 page_mapcount_reset(page); /* remove PageBuddy */
652 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
656 * Higher-order pages are called "compound pages". They are structured thusly:
658 * The first PAGE_SIZE page is called the "head page" and have PG_head set.
660 * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded
661 * in bit 0 of page->compound_head. The rest of bits is pointer to head page.
663 * The first tail page's ->compound_dtor holds the offset in array of compound
664 * page destructors. See compound_page_dtors.
666 * The first tail page's ->compound_order holds the order of allocation.
667 * This usage means that zero-order pages may not be compound.
670 void free_compound_page(struct page *page)
672 mem_cgroup_uncharge(page);
673 __free_pages_ok(page, compound_order(page));
676 void prep_compound_page(struct page *page, unsigned int order)
679 int nr_pages = 1 << order;
681 set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
682 set_compound_order(page, order);
684 for (i = 1; i < nr_pages; i++) {
685 struct page *p = page + i;
686 set_page_count(p, 0);
687 p->mapping = TAIL_MAPPING;
688 set_compound_head(p, page);
690 atomic_set(compound_mapcount_ptr(page), -1);
691 if (hpage_pincount_available(page))
692 atomic_set(compound_pincount_ptr(page), 0);
695 #ifdef CONFIG_DEBUG_PAGEALLOC
696 unsigned int _debug_guardpage_minorder;
698 bool _debug_pagealloc_enabled_early __read_mostly
699 = IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
700 EXPORT_SYMBOL(_debug_pagealloc_enabled_early);
701 DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
702 EXPORT_SYMBOL(_debug_pagealloc_enabled);
704 DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
706 static int __init early_debug_pagealloc(char *buf)
708 return kstrtobool(buf, &_debug_pagealloc_enabled_early);
710 early_param("debug_pagealloc", early_debug_pagealloc);
712 void init_debug_pagealloc(void)
714 if (!debug_pagealloc_enabled())
717 static_branch_enable(&_debug_pagealloc_enabled);
719 if (!debug_guardpage_minorder())
722 static_branch_enable(&_debug_guardpage_enabled);
725 static int __init debug_guardpage_minorder_setup(char *buf)
729 if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) {
730 pr_err("Bad debug_guardpage_minorder value\n");
733 _debug_guardpage_minorder = res;
734 pr_info("Setting debug_guardpage_minorder to %lu\n", res);
737 early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
739 static inline bool set_page_guard(struct zone *zone, struct page *page,
740 unsigned int order, int migratetype)
742 if (!debug_guardpage_enabled())
745 if (order >= debug_guardpage_minorder())
748 __SetPageGuard(page);
749 INIT_LIST_HEAD(&page->lru);
750 set_page_private(page, order);
751 /* Guard pages are not available for any usage */
752 __mod_zone_freepage_state(zone, -(1 << order), migratetype);
757 static inline void clear_page_guard(struct zone *zone, struct page *page,
758 unsigned int order, int migratetype)
760 if (!debug_guardpage_enabled())
763 __ClearPageGuard(page);
765 set_page_private(page, 0);
766 if (!is_migrate_isolate(migratetype))
767 __mod_zone_freepage_state(zone, (1 << order), migratetype);
770 static inline bool set_page_guard(struct zone *zone, struct page *page,
771 unsigned int order, int migratetype) { return false; }
772 static inline void clear_page_guard(struct zone *zone, struct page *page,
773 unsigned int order, int migratetype) {}
776 static inline void set_page_order(struct page *page, unsigned int order)
778 set_page_private(page, order);
779 __SetPageBuddy(page);
783 * This function checks whether a page is free && is the buddy
784 * we can coalesce a page and its buddy if
785 * (a) the buddy is not in a hole (check before calling!) &&
786 * (b) the buddy is in the buddy system &&
787 * (c) a page and its buddy have the same order &&
788 * (d) a page and its buddy are in the same zone.
790 * For recording whether a page is in the buddy system, we set PageBuddy.
791 * Setting, clearing, and testing PageBuddy is serialized by zone->lock.
793 * For recording page's order, we use page_private(page).
795 static inline int page_is_buddy(struct page *page, struct page *buddy,
798 if (page_is_guard(buddy) && page_order(buddy) == order) {
799 if (page_zone_id(page) != page_zone_id(buddy))
802 VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
807 if (PageBuddy(buddy) && page_order(buddy) == order) {
809 * zone check is done late to avoid uselessly
810 * calculating zone/node ids for pages that could
813 if (page_zone_id(page) != page_zone_id(buddy))
816 VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
823 #ifdef CONFIG_COMPACTION
824 static inline struct capture_control *task_capc(struct zone *zone)
826 struct capture_control *capc = current->capture_control;
829 !(current->flags & PF_KTHREAD) &&
831 capc->cc->zone == zone &&
832 capc->cc->direct_compaction ? capc : NULL;
836 compaction_capture(struct capture_control *capc, struct page *page,
837 int order, int migratetype)
839 if (!capc || order != capc->cc->order)
842 /* Do not accidentally pollute CMA or isolated regions*/
843 if (is_migrate_cma(migratetype) ||
844 is_migrate_isolate(migratetype))
848 * Do not let lower order allocations polluate a movable pageblock.
849 * This might let an unmovable request use a reclaimable pageblock
850 * and vice-versa but no more than normal fallback logic which can
851 * have trouble finding a high-order free page.
853 if (order < pageblock_order && migratetype == MIGRATE_MOVABLE)
861 static inline struct capture_control *task_capc(struct zone *zone)
867 compaction_capture(struct capture_control *capc, struct page *page,
868 int order, int migratetype)
872 #endif /* CONFIG_COMPACTION */
875 * Freeing function for a buddy system allocator.
877 * The concept of a buddy system is to maintain direct-mapped table
878 * (containing bit values) for memory blocks of various "orders".
879 * The bottom level table contains the map for the smallest allocatable
880 * units of memory (here, pages), and each level above it describes
881 * pairs of units from the levels below, hence, "buddies".
882 * At a high level, all that happens here is marking the table entry
883 * at the bottom level available, and propagating the changes upward
884 * as necessary, plus some accounting needed to play nicely with other
885 * parts of the VM system.
886 * At each level, we keep a list of pages, which are heads of continuous
887 * free pages of length of (1 << order) and marked with PageBuddy.
888 * Page's order is recorded in page_private(page) field.
889 * So when we are allocating or freeing one, we can derive the state of the
890 * other. That is, if we allocate a small block, and both were
891 * free, the remainder of the region must be split into blocks.
892 * If a block is freed, and its buddy is also free, then this
893 * triggers coalescing into a block of larger size.
898 static inline void __free_one_page(struct page *page,
900 struct zone *zone, unsigned int order,
903 unsigned long combined_pfn;
904 unsigned long uninitialized_var(buddy_pfn);
906 unsigned int max_order;
907 struct capture_control *capc = task_capc(zone);
909 max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);
911 VM_BUG_ON(!zone_is_initialized(zone));
912 VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
914 VM_BUG_ON(migratetype == -1);
915 if (likely(!is_migrate_isolate(migratetype)))
916 __mod_zone_freepage_state(zone, 1 << order, migratetype);
918 VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
919 VM_BUG_ON_PAGE(bad_range(zone, page), page);
922 while (order < max_order - 1) {
923 if (compaction_capture(capc, page, order, migratetype)) {
924 __mod_zone_freepage_state(zone, -(1 << order),
928 buddy_pfn = __find_buddy_pfn(pfn, order);
929 buddy = page + (buddy_pfn - pfn);
931 if (!pfn_valid_within(buddy_pfn))
933 if (!page_is_buddy(page, buddy, order))
936 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
937 * merge with it and move up one order.
939 if (page_is_guard(buddy))
940 clear_page_guard(zone, buddy, order, migratetype);
942 del_page_from_free_area(buddy, &zone->free_area[order]);
943 combined_pfn = buddy_pfn & pfn;
944 page = page + (combined_pfn - pfn);
948 if (max_order < MAX_ORDER) {
949 /* If we are here, it means order is >= pageblock_order.
950 * We want to prevent merge between freepages on isolate
951 * pageblock and normal pageblock. Without this, pageblock
952 * isolation could cause incorrect freepage or CMA accounting.
954 * We don't want to hit this code for the more frequent
957 if (unlikely(has_isolate_pageblock(zone))) {
960 buddy_pfn = __find_buddy_pfn(pfn, order);
961 buddy = page + (buddy_pfn - pfn);
962 buddy_mt = get_pageblock_migratetype(buddy);
964 if (migratetype != buddy_mt
965 && (is_migrate_isolate(migratetype) ||
966 is_migrate_isolate(buddy_mt)))
970 goto continue_merging;
974 set_page_order(page, order);
977 * If this is not the largest possible page, check if the buddy
978 * of the next-highest order is free. If it is, it's possible
979 * that pages are being freed that will coalesce soon. In case,
980 * that is happening, add the free page to the tail of the list
981 * so it's less likely to be used soon and more likely to be merged
982 * as a higher order page
984 if ((order < MAX_ORDER-2) && pfn_valid_within(buddy_pfn)
985 && !is_shuffle_order(order)) {
986 struct page *higher_page, *higher_buddy;
987 combined_pfn = buddy_pfn & pfn;
988 higher_page = page + (combined_pfn - pfn);
989 buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1);
990 higher_buddy = higher_page + (buddy_pfn - combined_pfn);
991 if (pfn_valid_within(buddy_pfn) &&
992 page_is_buddy(higher_page, higher_buddy, order + 1)) {
993 add_to_free_area_tail(page, &zone->free_area[order],
999 if (is_shuffle_order(order))
1000 add_to_free_area_random(page, &zone->free_area[order],
1003 add_to_free_area(page, &zone->free_area[order], migratetype);
1008 * A bad page could be due to a number of fields. Instead of multiple branches,
1009 * try and check multiple fields with one check. The caller must do a detailed
1010 * check if necessary.
1012 static inline bool page_expected_state(struct page *page,
1013 unsigned long check_flags)
1015 if (unlikely(atomic_read(&page->_mapcount) != -1))
1018 if (unlikely((unsigned long)page->mapping |
1019 page_ref_count(page) |
1021 (unsigned long)page->mem_cgroup |
1023 (page->flags & check_flags)))
1029 static void free_pages_check_bad(struct page *page)
1031 const char *bad_reason;
1032 unsigned long bad_flags;
1037 if (unlikely(atomic_read(&page->_mapcount) != -1))
1038 bad_reason = "nonzero mapcount";
1039 if (unlikely(page->mapping != NULL))
1040 bad_reason = "non-NULL mapping";
1041 if (unlikely(page_ref_count(page) != 0))
1042 bad_reason = "nonzero _refcount";
1043 if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
1044 bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
1045 bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
1048 if (unlikely(page->mem_cgroup))
1049 bad_reason = "page still charged to cgroup";
1051 bad_page(page, bad_reason, bad_flags);
1054 static inline int free_pages_check(struct page *page)
1056 if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE)))
1059 /* Something has gone sideways, find it */
1060 free_pages_check_bad(page);
1064 static int free_tail_pages_check(struct page *head_page, struct page *page)
1069 * We rely page->lru.next never has bit 0 set, unless the page
1070 * is PageTail(). Let's make sure that's true even for poisoned ->lru.
1072 BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1);
1074 if (!IS_ENABLED(CONFIG_DEBUG_VM)) {
1078 switch (page - head_page) {
1080 /* the first tail page: ->mapping may be compound_mapcount() */
1081 if (unlikely(compound_mapcount(page))) {
1082 bad_page(page, "nonzero compound_mapcount", 0);
1088 * the second tail page: ->mapping is
1089 * deferred_list.next -- ignore value.
1093 if (page->mapping != TAIL_MAPPING) {
1094 bad_page(page, "corrupted mapping in tail page", 0);
1099 if (unlikely(!PageTail(page))) {
1100 bad_page(page, "PageTail not set", 0);
1103 if (unlikely(compound_head(page) != head_page)) {
1104 bad_page(page, "compound_head not consistent", 0);
1109 page->mapping = NULL;
1110 clear_compound_head(page);
1114 static void kernel_init_free_pages(struct page *page, int numpages)
1118 for (i = 0; i < numpages; i++)
1119 clear_highpage(page + i);
1122 static __always_inline bool free_pages_prepare(struct page *page,
1123 unsigned int order, bool check_free)
1127 VM_BUG_ON_PAGE(PageTail(page), page);
1129 trace_mm_page_free(page, order);
1132 * Check tail pages before head page information is cleared to
1133 * avoid checking PageCompound for order-0 pages.
1135 if (unlikely(order)) {
1136 bool compound = PageCompound(page);
1139 VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
1142 ClearPageDoubleMap(page);
1143 for (i = 1; i < (1 << order); i++) {
1145 bad += free_tail_pages_check(page, page + i);
1146 if (unlikely(free_pages_check(page + i))) {
1150 (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1153 if (PageMappingFlags(page))
1154 page->mapping = NULL;
1155 if (memcg_kmem_enabled() && PageKmemcg(page))
1156 __memcg_kmem_uncharge_page(page, order);
1158 bad += free_pages_check(page);
1162 page_cpupid_reset_last(page);
1163 page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1164 reset_page_owner(page, order);
1166 if (!PageHighMem(page)) {
1167 debug_check_no_locks_freed(page_address(page),
1168 PAGE_SIZE << order);
1169 debug_check_no_obj_freed(page_address(page),
1170 PAGE_SIZE << order);
1172 if (want_init_on_free())
1173 kernel_init_free_pages(page, 1 << order);
1175 kernel_poison_pages(page, 1 << order, 0);
1177 * arch_free_page() can make the page's contents inaccessible. s390
1178 * does this. So nothing which can access the page's contents should
1179 * happen after this.
1181 arch_free_page(page, order);
1183 if (debug_pagealloc_enabled_static())
1184 kernel_map_pages(page, 1 << order, 0);
1186 kasan_free_nondeferred_pages(page, order);
1191 #ifdef CONFIG_DEBUG_VM
1193 * With DEBUG_VM enabled, order-0 pages are checked immediately when being freed
1194 * to pcp lists. With debug_pagealloc also enabled, they are also rechecked when
1195 * moved from pcp lists to free lists.
1197 static bool free_pcp_prepare(struct page *page)
1199 return free_pages_prepare(page, 0, true);
1202 static bool bulkfree_pcp_prepare(struct page *page)
1204 if (debug_pagealloc_enabled_static())
1205 return free_pages_check(page);
1211 * With DEBUG_VM disabled, order-0 pages being freed are checked only when
1212 * moving from pcp lists to free list in order to reduce overhead. With
1213 * debug_pagealloc enabled, they are checked also immediately when being freed
1216 static bool free_pcp_prepare(struct page *page)
1218 if (debug_pagealloc_enabled_static())
1219 return free_pages_prepare(page, 0, true);
1221 return free_pages_prepare(page, 0, false);
1224 static bool bulkfree_pcp_prepare(struct page *page)
1226 return free_pages_check(page);
1228 #endif /* CONFIG_DEBUG_VM */
1230 static inline void prefetch_buddy(struct page *page)
1232 unsigned long pfn = page_to_pfn(page);
1233 unsigned long buddy_pfn = __find_buddy_pfn(pfn, 0);
1234 struct page *buddy = page + (buddy_pfn - pfn);
1240 * Frees a number of pages from the PCP lists
1241 * Assumes all pages on list are in same zone, and of same order.
1242 * count is the number of pages to free.
1244 * If the zone was previously in an "all pages pinned" state then look to
1245 * see if this freeing clears that state.
1247 * And clear the zone's pages_scanned counter, to hold off the "all pages are
1248 * pinned" detection logic.
1250 static void free_pcppages_bulk(struct zone *zone, int count,
1251 struct per_cpu_pages *pcp)
1253 int migratetype = 0;
1255 int prefetch_nr = 0;
1256 bool isolated_pageblocks;
1257 struct page *page, *tmp;
1261 struct list_head *list;
1264 * Remove pages from lists in a round-robin fashion. A
1265 * batch_free count is maintained that is incremented when an
1266 * empty list is encountered. This is so more pages are freed
1267 * off fuller lists instead of spinning excessively around empty
1272 if (++migratetype == MIGRATE_PCPTYPES)
1274 list = &pcp->lists[migratetype];
1275 } while (list_empty(list));
1277 /* This is the only non-empty list. Free them all. */
1278 if (batch_free == MIGRATE_PCPTYPES)
1282 page = list_last_entry(list, struct page, lru);
1283 /* must delete to avoid corrupting pcp list */
1284 list_del(&page->lru);
1287 if (bulkfree_pcp_prepare(page))
1290 list_add_tail(&page->lru, &head);
1293 * We are going to put the page back to the global
1294 * pool, prefetch its buddy to speed up later access
1295 * under zone->lock. It is believed the overhead of
1296 * an additional test and calculating buddy_pfn here
1297 * can be offset by reduced memory latency later. To
1298 * avoid excessive prefetching due to large count, only
1299 * prefetch buddy for the first pcp->batch nr of pages.
1301 if (prefetch_nr++ < pcp->batch)
1302 prefetch_buddy(page);
1303 } while (--count && --batch_free && !list_empty(list));
1306 spin_lock(&zone->lock);
1307 isolated_pageblocks = has_isolate_pageblock(zone);
1310 * Use safe version since after __free_one_page(),
1311 * page->lru.next will not point to original list.
1313 list_for_each_entry_safe(page, tmp, &head, lru) {
1314 int mt = get_pcppage_migratetype(page);
1315 /* MIGRATE_ISOLATE page should not go to pcplists */
1316 VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
1317 /* Pageblock could have been isolated meanwhile */
1318 if (unlikely(isolated_pageblocks))
1319 mt = get_pageblock_migratetype(page);
1321 __free_one_page(page, page_to_pfn(page), zone, 0, mt);
1322 trace_mm_page_pcpu_drain(page, 0, mt);
1324 spin_unlock(&zone->lock);
1327 static void free_one_page(struct zone *zone,
1328 struct page *page, unsigned long pfn,
1332 spin_lock(&zone->lock);
1333 if (unlikely(has_isolate_pageblock(zone) ||
1334 is_migrate_isolate(migratetype))) {
1335 migratetype = get_pfnblock_migratetype(page, pfn);
1337 __free_one_page(page, pfn, zone, order, migratetype);
1338 spin_unlock(&zone->lock);
1341 static void __meminit __init_single_page(struct page *page, unsigned long pfn,
1342 unsigned long zone, int nid)
1344 mm_zero_struct_page(page);
1345 set_page_links(page, zone, nid, pfn);
1346 init_page_count(page);
1347 page_mapcount_reset(page);
1348 page_cpupid_reset_last(page);
1349 page_kasan_tag_reset(page);
1351 INIT_LIST_HEAD(&page->lru);
1352 #ifdef WANT_PAGE_VIRTUAL
1353 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
1354 if (!is_highmem_idx(zone))
1355 set_page_address(page, __va(pfn << PAGE_SHIFT));
1359 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1360 static void __meminit init_reserved_page(unsigned long pfn)
1365 if (!early_page_uninitialised(pfn))
1368 nid = early_pfn_to_nid(pfn);
1369 pgdat = NODE_DATA(nid);
1371 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1372 struct zone *zone = &pgdat->node_zones[zid];
1374 if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
1377 __init_single_page(pfn_to_page(pfn), pfn, zid, nid);
1380 static inline void init_reserved_page(unsigned long pfn)
1383 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1386 * Initialised pages do not have PageReserved set. This function is
1387 * called for each range allocated by the bootmem allocator and
1388 * marks the pages PageReserved. The remaining valid pages are later
1389 * sent to the buddy page allocator.
1391 void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
1393 unsigned long start_pfn = PFN_DOWN(start);
1394 unsigned long end_pfn = PFN_UP(end);
1396 for (; start_pfn < end_pfn; start_pfn++) {
1397 if (pfn_valid(start_pfn)) {
1398 struct page *page = pfn_to_page(start_pfn);
1400 init_reserved_page(start_pfn);
1402 /* Avoid false-positive PageTail() */
1403 INIT_LIST_HEAD(&page->lru);
1406 * no need for atomic set_bit because the struct
1407 * page is not visible yet so nobody should
1410 __SetPageReserved(page);
1415 static void __free_pages_ok(struct page *page, unsigned int order)
1417 unsigned long flags;
1419 unsigned long pfn = page_to_pfn(page);
1421 if (!free_pages_prepare(page, order, true))
1424 migratetype = get_pfnblock_migratetype(page, pfn);
1425 local_irq_save(flags);
1426 __count_vm_events(PGFREE, 1 << order);
1427 free_one_page(page_zone(page), page, pfn, order, migratetype);
1428 local_irq_restore(flags);
1431 void __free_pages_core(struct page *page, unsigned int order)
1433 unsigned int nr_pages = 1 << order;
1434 struct page *p = page;
1438 for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
1440 __ClearPageReserved(p);
1441 set_page_count(p, 0);
1443 __ClearPageReserved(p);
1444 set_page_count(p, 0);
1446 atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
1447 set_page_refcounted(page);
1448 __free_pages(page, order);
1451 #if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \
1452 defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
1454 static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
1456 int __meminit early_pfn_to_nid(unsigned long pfn)
1458 static DEFINE_SPINLOCK(early_pfn_lock);
1461 spin_lock(&early_pfn_lock);
1462 nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
1464 nid = first_online_node;
1465 spin_unlock(&early_pfn_lock);
1471 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
1472 /* Only safe to use early in boot when initialisation is single-threaded */
1473 static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
1477 nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
1478 if (nid >= 0 && nid != node)
1484 static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
1491 void __init memblock_free_pages(struct page *page, unsigned long pfn,
1494 if (early_page_uninitialised(pfn))
1496 __free_pages_core(page, order);
1500 * Check that the whole (or subset of) a pageblock given by the interval of
1501 * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
1502 * with the migration of free compaction scanner. The scanners then need to
1503 * use only pfn_valid_within() check for arches that allow holes within
1506 * Return struct page pointer of start_pfn, or NULL if checks were not passed.
1508 * It's possible on some configurations to have a setup like node0 node1 node0
1509 * i.e. it's possible that all pages within a zones range of pages do not
1510 * belong to a single zone. We assume that a border between node0 and node1
1511 * can occur within a single pageblock, but not a node0 node1 node0
1512 * interleaving within a single pageblock. It is therefore sufficient to check
1513 * the first and last page of a pageblock and avoid checking each individual
1514 * page in a pageblock.
1516 struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
1517 unsigned long end_pfn, struct zone *zone)
1519 struct page *start_page;
1520 struct page *end_page;
1522 /* end_pfn is one past the range we are checking */
1525 if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
1528 start_page = pfn_to_online_page(start_pfn);
1532 if (page_zone(start_page) != zone)
1535 end_page = pfn_to_page(end_pfn);
1537 /* This gives a shorter code than deriving page_zone(end_page) */
1538 if (page_zone_id(start_page) != page_zone_id(end_page))
1544 void set_zone_contiguous(struct zone *zone)
1546 unsigned long block_start_pfn = zone->zone_start_pfn;
1547 unsigned long block_end_pfn;
1549 block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages);
1550 for (; block_start_pfn < zone_end_pfn(zone);
1551 block_start_pfn = block_end_pfn,
1552 block_end_pfn += pageblock_nr_pages) {
1554 block_end_pfn = min(block_end_pfn, zone_end_pfn(zone));
1556 if (!__pageblock_pfn_to_page(block_start_pfn,
1557 block_end_pfn, zone))
1561 /* We confirm that there is no hole */
1562 zone->contiguous = true;
1565 void clear_zone_contiguous(struct zone *zone)
1567 zone->contiguous = false;
1570 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1571 static void __init deferred_free_range(unsigned long pfn,
1572 unsigned long nr_pages)
1580 page = pfn_to_page(pfn);
1582 /* Free a large naturally-aligned chunk if possible */
1583 if (nr_pages == pageblock_nr_pages &&
1584 (pfn & (pageblock_nr_pages - 1)) == 0) {
1585 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1586 __free_pages_core(page, pageblock_order);
1590 for (i = 0; i < nr_pages; i++, page++, pfn++) {
1591 if ((pfn & (pageblock_nr_pages - 1)) == 0)
1592 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1593 __free_pages_core(page, 0);
1597 /* Completion tracking for deferred_init_memmap() threads */
1598 static atomic_t pgdat_init_n_undone __initdata;
1599 static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp);
1601 static inline void __init pgdat_init_report_one_done(void)
1603 if (atomic_dec_and_test(&pgdat_init_n_undone))
1604 complete(&pgdat_init_all_done_comp);
1608 * Returns true if page needs to be initialized or freed to buddy allocator.
1610 * First we check if pfn is valid on architectures where it is possible to have
1611 * holes within pageblock_nr_pages. On systems where it is not possible, this
1612 * function is optimized out.
1614 * Then, we check if a current large page is valid by only checking the validity
1617 static inline bool __init deferred_pfn_valid(unsigned long pfn)
1619 if (!pfn_valid_within(pfn))
1621 if (!(pfn & (pageblock_nr_pages - 1)) && !pfn_valid(pfn))
1627 * Free pages to buddy allocator. Try to free aligned pages in
1628 * pageblock_nr_pages sizes.
1630 static void __init deferred_free_pages(unsigned long pfn,
1631 unsigned long end_pfn)
1633 unsigned long nr_pgmask = pageblock_nr_pages - 1;
1634 unsigned long nr_free = 0;
1636 for (; pfn < end_pfn; pfn++) {
1637 if (!deferred_pfn_valid(pfn)) {
1638 deferred_free_range(pfn - nr_free, nr_free);
1640 } else if (!(pfn & nr_pgmask)) {
1641 deferred_free_range(pfn - nr_free, nr_free);
1643 touch_nmi_watchdog();
1648 /* Free the last block of pages to allocator */
1649 deferred_free_range(pfn - nr_free, nr_free);
1653 * Initialize struct pages. We minimize pfn page lookups and scheduler checks
1654 * by performing it only once every pageblock_nr_pages.
1655 * Return number of pages initialized.
1657 static unsigned long __init deferred_init_pages(struct zone *zone,
1659 unsigned long end_pfn)
1661 unsigned long nr_pgmask = pageblock_nr_pages - 1;
1662 int nid = zone_to_nid(zone);
1663 unsigned long nr_pages = 0;
1664 int zid = zone_idx(zone);
1665 struct page *page = NULL;
1667 for (; pfn < end_pfn; pfn++) {
1668 if (!deferred_pfn_valid(pfn)) {
1671 } else if (!page || !(pfn & nr_pgmask)) {
1672 page = pfn_to_page(pfn);
1673 touch_nmi_watchdog();
1677 __init_single_page(page, pfn, zid, nid);
1684 * This function is meant to pre-load the iterator for the zone init.
1685 * Specifically it walks through the ranges until we are caught up to the
1686 * first_init_pfn value and exits there. If we never encounter the value we
1687 * return false indicating there are no valid ranges left.
1690 deferred_init_mem_pfn_range_in_zone(u64 *i, struct zone *zone,
1691 unsigned long *spfn, unsigned long *epfn,
1692 unsigned long first_init_pfn)
1697 * Start out by walking through the ranges in this zone that have
1698 * already been initialized. We don't need to do anything with them
1699 * so we just need to flush them out of the system.
1701 for_each_free_mem_pfn_range_in_zone(j, zone, spfn, epfn) {
1702 if (*epfn <= first_init_pfn)
1704 if (*spfn < first_init_pfn)
1705 *spfn = first_init_pfn;
1714 * Initialize and free pages. We do it in two loops: first we initialize
1715 * struct page, then free to buddy allocator, because while we are
1716 * freeing pages we can access pages that are ahead (computing buddy
1717 * page in __free_one_page()).
1719 * In order to try and keep some memory in the cache we have the loop
1720 * broken along max page order boundaries. This way we will not cause
1721 * any issues with the buddy page computation.
1723 static unsigned long __init
1724 deferred_init_maxorder(u64 *i, struct zone *zone, unsigned long *start_pfn,
1725 unsigned long *end_pfn)
1727 unsigned long mo_pfn = ALIGN(*start_pfn + 1, MAX_ORDER_NR_PAGES);
1728 unsigned long spfn = *start_pfn, epfn = *end_pfn;
1729 unsigned long nr_pages = 0;
1732 /* First we loop through and initialize the page values */
1733 for_each_free_mem_pfn_range_in_zone_from(j, zone, start_pfn, end_pfn) {
1736 if (mo_pfn <= *start_pfn)
1739 t = min(mo_pfn, *end_pfn);
1740 nr_pages += deferred_init_pages(zone, *start_pfn, t);
1742 if (mo_pfn < *end_pfn) {
1743 *start_pfn = mo_pfn;
1748 /* Reset values and now loop through freeing pages as needed */
1751 for_each_free_mem_pfn_range_in_zone_from(j, zone, &spfn, &epfn) {
1757 t = min(mo_pfn, epfn);
1758 deferred_free_pages(spfn, t);
1767 /* Initialise remaining memory on a node */
1768 static int __init deferred_init_memmap(void *data)
1770 pg_data_t *pgdat = data;
1771 const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
1772 unsigned long spfn = 0, epfn = 0, nr_pages = 0;
1773 unsigned long first_init_pfn, flags;
1774 unsigned long start = jiffies;
1779 /* Bind memory initialisation thread to a local node if possible */
1780 if (!cpumask_empty(cpumask))
1781 set_cpus_allowed_ptr(current, cpumask);
1783 pgdat_resize_lock(pgdat, &flags);
1784 first_init_pfn = pgdat->first_deferred_pfn;
1785 if (first_init_pfn == ULONG_MAX) {
1786 pgdat_resize_unlock(pgdat, &flags);
1787 pgdat_init_report_one_done();
1791 /* Sanity check boundaries */
1792 BUG_ON(pgdat->first_deferred_pfn < pgdat->node_start_pfn);
1793 BUG_ON(pgdat->first_deferred_pfn > pgdat_end_pfn(pgdat));
1794 pgdat->first_deferred_pfn = ULONG_MAX;
1796 /* Only the highest zone is deferred so find it */
1797 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1798 zone = pgdat->node_zones + zid;
1799 if (first_init_pfn < zone_end_pfn(zone))
1803 /* If the zone is empty somebody else may have cleared out the zone */
1804 if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
1809 * Initialize and free pages in MAX_ORDER sized increments so
1810 * that we can avoid introducing any issues with the buddy
1814 nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
1816 pgdat_resize_unlock(pgdat, &flags);
1818 /* Sanity check that the next zone really is unpopulated */
1819 WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));
1821 pr_info("node %d initialised, %lu pages in %ums\n",
1822 pgdat->node_id, nr_pages, jiffies_to_msecs(jiffies - start));
1824 pgdat_init_report_one_done();
1829 * If this zone has deferred pages, try to grow it by initializing enough
1830 * deferred pages to satisfy the allocation specified by order, rounded up to
1831 * the nearest PAGES_PER_SECTION boundary. So we're adding memory in increments
1832 * of SECTION_SIZE bytes by initializing struct pages in increments of
1833 * PAGES_PER_SECTION * sizeof(struct page) bytes.
1835 * Return true when zone was grown, otherwise return false. We return true even
1836 * when we grow less than requested, to let the caller decide if there are
1837 * enough pages to satisfy the allocation.
1839 * Note: We use noinline because this function is needed only during boot, and
1840 * it is called from a __ref function _deferred_grow_zone. This way we are
1841 * making sure that it is not inlined into permanent text section.
1843 static noinline bool __init
1844 deferred_grow_zone(struct zone *zone, unsigned int order)
1846 unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION);
1847 pg_data_t *pgdat = zone->zone_pgdat;
1848 unsigned long first_deferred_pfn = pgdat->first_deferred_pfn;
1849 unsigned long spfn, epfn, flags;
1850 unsigned long nr_pages = 0;
1853 /* Only the last zone may have deferred pages */
1854 if (zone_end_pfn(zone) != pgdat_end_pfn(pgdat))
1857 pgdat_resize_lock(pgdat, &flags);
1860 * If deferred pages have been initialized while we were waiting for
1861 * the lock, return true, as the zone was grown. The caller will retry
1862 * this zone. We won't return to this function since the caller also
1863 * has this static branch.
1865 if (!static_branch_unlikely(&deferred_pages)) {
1866 pgdat_resize_unlock(pgdat, &flags);
1871 * If someone grew this zone while we were waiting for spinlock, return
1872 * true, as there might be enough pages already.
1874 if (first_deferred_pfn != pgdat->first_deferred_pfn) {
1875 pgdat_resize_unlock(pgdat, &flags);
1879 /* If the zone is empty somebody else may have cleared out the zone */
1880 if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
1881 first_deferred_pfn)) {
1882 pgdat->first_deferred_pfn = ULONG_MAX;
1883 pgdat_resize_unlock(pgdat, &flags);
1884 /* Retry only once. */
1885 return first_deferred_pfn != ULONG_MAX;
1889 * Initialize and free pages in MAX_ORDER sized increments so
1890 * that we can avoid introducing any issues with the buddy
1893 while (spfn < epfn) {
1894 /* update our first deferred PFN for this section */
1895 first_deferred_pfn = spfn;
1897 nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
1899 /* We should only stop along section boundaries */
1900 if ((first_deferred_pfn ^ spfn) < PAGES_PER_SECTION)
1903 /* If our quota has been met we can stop here */
1904 if (nr_pages >= nr_pages_needed)
1908 pgdat->first_deferred_pfn = spfn;
1909 pgdat_resize_unlock(pgdat, &flags);
1911 return nr_pages > 0;
1915 * deferred_grow_zone() is __init, but it is called from
1916 * get_page_from_freelist() during early boot until deferred_pages permanently
1917 * disables this call. This is why we have refdata wrapper to avoid warning,
1918 * and to ensure that the function body gets unloaded.
1921 _deferred_grow_zone(struct zone *zone, unsigned int order)
1923 return deferred_grow_zone(zone, order);
1926 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1928 void __init page_alloc_init_late(void)
1933 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1935 /* There will be num_node_state(N_MEMORY) threads */
1936 atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY));
1937 for_each_node_state(nid, N_MEMORY) {
1938 kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid);
1941 /* Block until all are initialised */
1942 wait_for_completion(&pgdat_init_all_done_comp);
1945 * The number of managed pages has changed due to the initialisation
1946 * so the pcpu batch and high limits needs to be updated or the limits
1947 * will be artificially small.
1949 for_each_populated_zone(zone)
1950 zone_pcp_update(zone);
1953 * We initialized the rest of the deferred pages. Permanently disable
1954 * on-demand struct page initialization.
1956 static_branch_disable(&deferred_pages);
1958 /* Reinit limits that are based on free pages after the kernel is up */
1959 files_maxfiles_init();
1962 /* Discard memblock private memory */
1965 for_each_node_state(nid, N_MEMORY)
1966 shuffle_free_memory(NODE_DATA(nid));
1968 for_each_populated_zone(zone)
1969 set_zone_contiguous(zone);
1973 /* Free whole pageblock and set its migration type to MIGRATE_CMA. */
1974 void __init init_cma_reserved_pageblock(struct page *page)
1976 unsigned i = pageblock_nr_pages;
1977 struct page *p = page;
1980 __ClearPageReserved(p);
1981 set_page_count(p, 0);
1984 set_pageblock_migratetype(page, MIGRATE_CMA);
1986 if (pageblock_order >= MAX_ORDER) {
1987 i = pageblock_nr_pages;
1990 set_page_refcounted(p);
1991 __free_pages(p, MAX_ORDER - 1);
1992 p += MAX_ORDER_NR_PAGES;
1993 } while (i -= MAX_ORDER_NR_PAGES);
1995 set_page_refcounted(page);
1996 __free_pages(page, pageblock_order);
1999 adjust_managed_page_count(page, pageblock_nr_pages);
2004 * The order of subdivision here is critical for the IO subsystem.
2005 * Please do not alter this order without good reasons and regression
2006 * testing. Specifically, as large blocks of memory are subdivided,
2007 * the order in which smaller blocks are delivered depends on the order
2008 * they're subdivided in this function. This is the primary factor
2009 * influencing the order in which pages are delivered to the IO
2010 * subsystem according to empirical testing, and this is also justified
2011 * by considering the behavior of a buddy system containing a single
2012 * large block of memory acted on by a series of small allocations.
2013 * This behavior is a critical factor in sglist merging's success.
2017 static inline void expand(struct zone *zone, struct page *page,
2018 int low, int high, struct free_area *area,
2021 unsigned long size = 1 << high;
2023 while (high > low) {
2027 VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
2030 * Mark as guard pages (or page), that will allow to
2031 * merge back to allocator when buddy will be freed.
2032 * Corresponding page table entries will not be touched,
2033 * pages will stay not present in virtual address space
2035 if (set_page_guard(zone, &page[size], high, migratetype))
2038 add_to_free_area(&page[size], area, migratetype);
2039 set_page_order(&page[size], high);
2043 static void check_new_page_bad(struct page *page)
2045 const char *bad_reason = NULL;
2046 unsigned long bad_flags = 0;
2048 if (unlikely(atomic_read(&page->_mapcount) != -1))
2049 bad_reason = "nonzero mapcount";
2050 if (unlikely(page->mapping != NULL))
2051 bad_reason = "non-NULL mapping";
2052 if (unlikely(page_ref_count(page) != 0))
2053 bad_reason = "nonzero _refcount";
2054 if (unlikely(page->flags & __PG_HWPOISON)) {
2055 bad_reason = "HWPoisoned (hardware-corrupted)";
2056 bad_flags = __PG_HWPOISON;
2057 /* Don't complain about hwpoisoned pages */
2058 page_mapcount_reset(page); /* remove PageBuddy */
2061 if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
2062 bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
2063 bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
2066 if (unlikely(page->mem_cgroup))
2067 bad_reason = "page still charged to cgroup";
2069 bad_page(page, bad_reason, bad_flags);
2073 * This page is about to be returned from the page allocator
2075 static inline int check_new_page(struct page *page)
2077 if (likely(page_expected_state(page,
2078 PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON)))
2081 check_new_page_bad(page);
2085 static inline bool free_pages_prezeroed(void)
2087 return (IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) &&
2088 page_poisoning_enabled()) || want_init_on_free();
2091 #ifdef CONFIG_DEBUG_VM
2093 * With DEBUG_VM enabled, order-0 pages are checked for expected state when
2094 * being allocated from pcp lists. With debug_pagealloc also enabled, they are
2095 * also checked when pcp lists are refilled from the free lists.
2097 static inline bool check_pcp_refill(struct page *page)
2099 if (debug_pagealloc_enabled_static())
2100 return check_new_page(page);
2105 static inline bool check_new_pcp(struct page *page)
2107 return check_new_page(page);
2111 * With DEBUG_VM disabled, free order-0 pages are checked for expected state
2112 * when pcp lists are being refilled from the free lists. With debug_pagealloc
2113 * enabled, they are also checked when being allocated from the pcp lists.
2115 static inline bool check_pcp_refill(struct page *page)
2117 return check_new_page(page);
2119 static inline bool check_new_pcp(struct page *page)
2121 if (debug_pagealloc_enabled_static())
2122 return check_new_page(page);
2126 #endif /* CONFIG_DEBUG_VM */
2128 static bool check_new_pages(struct page *page, unsigned int order)
2131 for (i = 0; i < (1 << order); i++) {
2132 struct page *p = page + i;
2134 if (unlikely(check_new_page(p)))
2141 inline void post_alloc_hook(struct page *page, unsigned int order,
2144 set_page_private(page, 0);
2145 set_page_refcounted(page);
2147 arch_alloc_page(page, order);
2148 if (debug_pagealloc_enabled_static())
2149 kernel_map_pages(page, 1 << order, 1);
2150 kasan_alloc_pages(page, order);
2151 kernel_poison_pages(page, 1 << order, 1);
2152 set_page_owner(page, order, gfp_flags);
2155 static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
2156 unsigned int alloc_flags)
2158 post_alloc_hook(page, order, gfp_flags);
2160 if (!free_pages_prezeroed() && want_init_on_alloc(gfp_flags))
2161 kernel_init_free_pages(page, 1 << order);
2163 if (order && (gfp_flags & __GFP_COMP))
2164 prep_compound_page(page, order);
2167 * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
2168 * allocate the page. The expectation is that the caller is taking
2169 * steps that will free more memory. The caller should avoid the page
2170 * being used for !PFMEMALLOC purposes.
2172 if (alloc_flags & ALLOC_NO_WATERMARKS)
2173 set_page_pfmemalloc(page);
2175 clear_page_pfmemalloc(page);
2179 * Go through the free lists for the given migratetype and remove
2180 * the smallest available page from the freelists
2182 static __always_inline
2183 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
2186 unsigned int current_order;
2187 struct free_area *area;
2190 /* Find a page of the appropriate size in the preferred list */
2191 for (current_order = order; current_order < MAX_ORDER; ++current_order) {
2192 area = &(zone->free_area[current_order]);
2193 page = get_page_from_free_area(area, migratetype);
2196 del_page_from_free_area(page, area);
2197 expand(zone, page, order, current_order, area, migratetype);
2198 set_pcppage_migratetype(page, migratetype);
2207 * This array describes the order lists are fallen back to when
2208 * the free lists for the desirable migrate type are depleted
2210 static int fallbacks[MIGRATE_TYPES][4] = {
2211 [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
2212 [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
2213 [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
2215 [MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */
2217 #ifdef CONFIG_MEMORY_ISOLATION
2218 [MIGRATE_ISOLATE] = { MIGRATE_TYPES }, /* Never used */
2223 static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone,
2226 return __rmqueue_smallest(zone, order, MIGRATE_CMA);
2229 static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
2230 unsigned int order) { return NULL; }
2234 * Move the free pages in a range to the free lists of the requested type.
2235 * Note that start_page and end_pages are not aligned on a pageblock
2236 * boundary. If alignment is required, use move_freepages_block()
2238 static int move_freepages(struct zone *zone,
2239 struct page *start_page, struct page *end_page,
2240 int migratetype, int *num_movable)
2244 int pages_moved = 0;
2246 for (page = start_page; page <= end_page;) {
2247 if (!pfn_valid_within(page_to_pfn(page))) {
2252 if (!PageBuddy(page)) {
2254 * We assume that pages that could be isolated for
2255 * migration are movable. But we don't actually try
2256 * isolating, as that would be expensive.
2259 (PageLRU(page) || __PageMovable(page)))
2266 /* Make sure we are not inadvertently changing nodes */
2267 VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
2268 VM_BUG_ON_PAGE(page_zone(page) != zone, page);
2270 order = page_order(page);
2271 move_to_free_area(page, &zone->free_area[order], migratetype);
2273 pages_moved += 1 << order;
2279 int move_freepages_block(struct zone *zone, struct page *page,
2280 int migratetype, int *num_movable)
2282 unsigned long start_pfn, end_pfn;
2283 struct page *start_page, *end_page;
2288 start_pfn = page_to_pfn(page);
2289 start_pfn = start_pfn & ~(pageblock_nr_pages-1);
2290 start_page = pfn_to_page(start_pfn);
2291 end_page = start_page + pageblock_nr_pages - 1;
2292 end_pfn = start_pfn + pageblock_nr_pages - 1;
2294 /* Do not cross zone boundaries */
2295 if (!zone_spans_pfn(zone, start_pfn))
2297 if (!zone_spans_pfn(zone, end_pfn))
2300 return move_freepages(zone, start_page, end_page, migratetype,
2304 static void change_pageblock_range(struct page *pageblock_page,
2305 int start_order, int migratetype)
2307 int nr_pageblocks = 1 << (start_order - pageblock_order);
2309 while (nr_pageblocks--) {
2310 set_pageblock_migratetype(pageblock_page, migratetype);
2311 pageblock_page += pageblock_nr_pages;
2316 * When we are falling back to another migratetype during allocation, try to
2317 * steal extra free pages from the same pageblocks to satisfy further
2318 * allocations, instead of polluting multiple pageblocks.
2320 * If we are stealing a relatively large buddy page, it is likely there will
2321 * be more free pages in the pageblock, so try to steal them all. For
2322 * reclaimable and unmovable allocations, we steal regardless of page size,
2323 * as fragmentation caused by those allocations polluting movable pageblocks
2324 * is worse than movable allocations stealing from unmovable and reclaimable
2327 static bool can_steal_fallback(unsigned int order, int start_mt)
2330 * Leaving this order check is intended, although there is
2331 * relaxed order check in next check. The reason is that
2332 * we can actually steal whole pageblock if this condition met,
2333 * but, below check doesn't guarantee it and that is just heuristic
2334 * so could be changed anytime.
2336 if (order >= pageblock_order)
2339 if (order >= pageblock_order / 2 ||
2340 start_mt == MIGRATE_RECLAIMABLE ||
2341 start_mt == MIGRATE_UNMOVABLE ||
2342 page_group_by_mobility_disabled)
2348 static inline void boost_watermark(struct zone *zone)
2350 unsigned long max_boost;
2352 if (!watermark_boost_factor)
2355 max_boost = mult_frac(zone->_watermark[WMARK_HIGH],
2356 watermark_boost_factor, 10000);
2359 * high watermark may be uninitialised if fragmentation occurs
2360 * very early in boot so do not boost. We do not fall
2361 * through and boost by pageblock_nr_pages as failing
2362 * allocations that early means that reclaim is not going
2363 * to help and it may even be impossible to reclaim the
2364 * boosted watermark resulting in a hang.
2369 max_boost = max(pageblock_nr_pages, max_boost);
2371 zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages,
2376 * This function implements actual steal behaviour. If order is large enough,
2377 * we can steal whole pageblock. If not, we first move freepages in this
2378 * pageblock to our migratetype and determine how many already-allocated pages
2379 * are there in the pageblock with a compatible migratetype. If at least half
2380 * of pages are free or compatible, we can change migratetype of the pageblock
2381 * itself, so pages freed in the future will be put on the correct free list.
2383 static void steal_suitable_fallback(struct zone *zone, struct page *page,
2384 unsigned int alloc_flags, int start_type, bool whole_block)
2386 unsigned int current_order = page_order(page);
2387 struct free_area *area;
2388 int free_pages, movable_pages, alike_pages;
2391 old_block_type = get_pageblock_migratetype(page);
2394 * This can happen due to races and we want to prevent broken
2395 * highatomic accounting.
2397 if (is_migrate_highatomic(old_block_type))
2400 /* Take ownership for orders >= pageblock_order */
2401 if (current_order >= pageblock_order) {
2402 change_pageblock_range(page, current_order, start_type);
2407 * Boost watermarks to increase reclaim pressure to reduce the
2408 * likelihood of future fallbacks. Wake kswapd now as the node
2409 * may be balanced overall and kswapd will not wake naturally.
2411 boost_watermark(zone);
2412 if (alloc_flags & ALLOC_KSWAPD)
2413 set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
2415 /* We are not allowed to try stealing from the whole block */
2419 free_pages = move_freepages_block(zone, page, start_type,
2422 * Determine how many pages are compatible with our allocation.
2423 * For movable allocation, it's the number of movable pages which
2424 * we just obtained. For other types it's a bit more tricky.
2426 if (start_type == MIGRATE_MOVABLE) {
2427 alike_pages = movable_pages;
2430 * If we are falling back a RECLAIMABLE or UNMOVABLE allocation
2431 * to MOVABLE pageblock, consider all non-movable pages as
2432 * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or
2433 * vice versa, be conservative since we can't distinguish the
2434 * exact migratetype of non-movable pages.
2436 if (old_block_type == MIGRATE_MOVABLE)
2437 alike_pages = pageblock_nr_pages
2438 - (free_pages + movable_pages);
2443 /* moving whole block can fail due to zone boundary conditions */
2448 * If a sufficient number of pages in the block are either free or of
2449 * comparable migratability as our allocation, claim the whole block.
2451 if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||
2452 page_group_by_mobility_disabled)
2453 set_pageblock_migratetype(page, start_type);
2458 area = &zone->free_area[current_order];
2459 move_to_free_area(page, area, start_type);
2463 * Check whether there is a suitable fallback freepage with requested order.
2464 * If only_stealable is true, this function returns fallback_mt only if
2465 * we can steal other freepages all together. This would help to reduce
2466 * fragmentation due to mixed migratetype pages in one pageblock.
2468 int find_suitable_fallback(struct free_area *area, unsigned int order,
2469 int migratetype, bool only_stealable, bool *can_steal)
2474 if (area->nr_free == 0)
2479 fallback_mt = fallbacks[migratetype][i];
2480 if (fallback_mt == MIGRATE_TYPES)
2483 if (free_area_empty(area, fallback_mt))
2486 if (can_steal_fallback(order, migratetype))
2489 if (!only_stealable)
2500 * Reserve a pageblock for exclusive use of high-order atomic allocations if
2501 * there are no empty page blocks that contain a page with a suitable order
2503 static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
2504 unsigned int alloc_order)
2507 unsigned long max_managed, flags;
2510 * Limit the number reserved to 1 pageblock or roughly 1% of a zone.
2511 * Check is race-prone but harmless.
2513 max_managed = (zone_managed_pages(zone) / 100) + pageblock_nr_pages;
2514 if (zone->nr_reserved_highatomic >= max_managed)
2517 spin_lock_irqsave(&zone->lock, flags);
2519 /* Recheck the nr_reserved_highatomic limit under the lock */
2520 if (zone->nr_reserved_highatomic >= max_managed)
2524 mt = get_pageblock_migratetype(page);
2525 if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt)
2526 && !is_migrate_cma(mt)) {
2527 zone->nr_reserved_highatomic += pageblock_nr_pages;
2528 set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
2529 move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL);
2533 spin_unlock_irqrestore(&zone->lock, flags);
2537 * Used when an allocation is about to fail under memory pressure. This
2538 * potentially hurts the reliability of high-order allocations when under
2539 * intense memory pressure but failed atomic allocations should be easier
2540 * to recover from than an OOM.
2542 * If @force is true, try to unreserve a pageblock even though highatomic
2543 * pageblock is exhausted.
2545 static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
2548 struct zonelist *zonelist = ac->zonelist;
2549 unsigned long flags;
2556 for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->high_zoneidx,
2559 * Preserve at least one pageblock unless memory pressure
2562 if (!force && zone->nr_reserved_highatomic <=
2566 spin_lock_irqsave(&zone->lock, flags);
2567 for (order = 0; order < MAX_ORDER; order++) {
2568 struct free_area *area = &(zone->free_area[order]);
2570 page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
2575 * In page freeing path, migratetype change is racy so
2576 * we can counter several free pages in a pageblock
2577 * in this loop althoug we changed the pageblock type
2578 * from highatomic to ac->migratetype. So we should
2579 * adjust the count once.
2581 if (is_migrate_highatomic_page(page)) {
2583 * It should never happen but changes to
2584 * locking could inadvertently allow a per-cpu
2585 * drain to add pages to MIGRATE_HIGHATOMIC
2586 * while unreserving so be safe and watch for
2589 zone->nr_reserved_highatomic -= min(
2591 zone->nr_reserved_highatomic);
2595 * Convert to ac->migratetype and avoid the normal
2596 * pageblock stealing heuristics. Minimally, the caller
2597 * is doing the work and needs the pages. More
2598 * importantly, if the block was always converted to
2599 * MIGRATE_UNMOVABLE or another type then the number
2600 * of pageblocks that cannot be completely freed
2603 set_pageblock_migratetype(page, ac->migratetype);
2604 ret = move_freepages_block(zone, page, ac->migratetype,
2607 spin_unlock_irqrestore(&zone->lock, flags);
2611 spin_unlock_irqrestore(&zone->lock, flags);
2618 * Try finding a free buddy page on the fallback list and put it on the free
2619 * list of requested migratetype, possibly along with other pages from the same
2620 * block, depending on fragmentation avoidance heuristics. Returns true if
2621 * fallback was found so that __rmqueue_smallest() can grab it.
2623 * The use of signed ints for order and current_order is a deliberate
2624 * deviation from the rest of this file, to make the for loop
2625 * condition simpler.
2627 static __always_inline bool
2628 __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
2629 unsigned int alloc_flags)
2631 struct free_area *area;
2633 int min_order = order;
2639 * Do not steal pages from freelists belonging to other pageblocks
2640 * i.e. orders < pageblock_order. If there are no local zones free,
2641 * the zonelists will be reiterated without ALLOC_NOFRAGMENT.
2643 if (alloc_flags & ALLOC_NOFRAGMENT)
2644 min_order = pageblock_order;
2647 * Find the largest available free page in the other list. This roughly
2648 * approximates finding the pageblock with the most free pages, which
2649 * would be too costly to do exactly.
2651 for (current_order = MAX_ORDER - 1; current_order >= min_order;
2653 area = &(zone->free_area[current_order]);
2654 fallback_mt = find_suitable_fallback(area, current_order,
2655 start_migratetype, false, &can_steal);
2656 if (fallback_mt == -1)
2660 * We cannot steal all free pages from the pageblock and the
2661 * requested migratetype is movable. In that case it's better to
2662 * steal and split the smallest available page instead of the
2663 * largest available page, because even if the next movable
2664 * allocation falls back into a different pageblock than this
2665 * one, it won't cause permanent fragmentation.
2667 if (!can_steal && start_migratetype == MIGRATE_MOVABLE
2668 && current_order > order)
2677 for (current_order = order; current_order < MAX_ORDER;
2679 area = &(zone->free_area[current_order]);
2680 fallback_mt = find_suitable_fallback(area, current_order,
2681 start_migratetype, false, &can_steal);
2682 if (fallback_mt != -1)
2687 * This should not happen - we already found a suitable fallback
2688 * when looking for the largest page.
2690 VM_BUG_ON(current_order == MAX_ORDER);
2693 page = get_page_from_free_area(area, fallback_mt);
2695 steal_suitable_fallback(zone, page, alloc_flags, start_migratetype,
2698 trace_mm_page_alloc_extfrag(page, order, current_order,
2699 start_migratetype, fallback_mt);
2706 * Do the hard work of removing an element from the buddy allocator.
2707 * Call me with the zone->lock already held.
2709 static __always_inline struct page *
2710 __rmqueue(struct zone *zone, unsigned int order, int migratetype,
2711 unsigned int alloc_flags)
2716 page = __rmqueue_smallest(zone, order, migratetype);
2717 if (unlikely(!page)) {
2718 if (migratetype == MIGRATE_MOVABLE)
2719 page = __rmqueue_cma_fallback(zone, order);
2721 if (!page && __rmqueue_fallback(zone, order, migratetype,
2726 trace_mm_page_alloc_zone_locked(page, order, migratetype);
2731 * Obtain a specified number of elements from the buddy allocator, all under
2732 * a single hold of the lock, for efficiency. Add them to the supplied list.
2733 * Returns the number of new pages which were placed at *list.
2735 static int rmqueue_bulk(struct zone *zone, unsigned int order,
2736 unsigned long count, struct list_head *list,
2737 int migratetype, unsigned int alloc_flags)
2741 spin_lock(&zone->lock);
2742 for (i = 0; i < count; ++i) {
2743 struct page *page = __rmqueue(zone, order, migratetype,
2745 if (unlikely(page == NULL))
2748 if (unlikely(check_pcp_refill(page)))
2752 * Split buddy pages returned by expand() are received here in
2753 * physical page order. The page is added to the tail of
2754 * caller's list. From the callers perspective, the linked list
2755 * is ordered by page number under some conditions. This is
2756 * useful for IO devices that can forward direction from the
2757 * head, thus also in the physical page order. This is useful
2758 * for IO devices that can merge IO requests if the physical
2759 * pages are ordered properly.
2761 list_add_tail(&page->lru, list);
2763 if (is_migrate_cma(get_pcppage_migratetype(page)))
2764 __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
2769 * i pages were removed from the buddy list even if some leak due
2770 * to check_pcp_refill failing so adjust NR_FREE_PAGES based
2771 * on i. Do not confuse with 'alloced' which is the number of
2772 * pages added to the pcp list.
2774 __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
2775 spin_unlock(&zone->lock);
2781 * Called from the vmstat counter updater to drain pagesets of this
2782 * currently executing processor on remote nodes after they have
2785 * Note that this function must be called with the thread pinned to
2786 * a single processor.
2788 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
2790 unsigned long flags;
2791 int to_drain, batch;
2793 local_irq_save(flags);
2794 batch = READ_ONCE(pcp->batch);
2795 to_drain = min(pcp->count, batch);
2797 free_pcppages_bulk(zone, to_drain, pcp);
2798 local_irq_restore(flags);
2803 * Drain pcplists of the indicated processor and zone.
2805 * The processor must either be the current processor and the
2806 * thread pinned to the current processor or a processor that
2809 static void drain_pages_zone(unsigned int cpu, struct zone *zone)
2811 unsigned long flags;
2812 struct per_cpu_pageset *pset;
2813 struct per_cpu_pages *pcp;
2815 local_irq_save(flags);
2816 pset = per_cpu_ptr(zone->pageset, cpu);
2820 free_pcppages_bulk(zone, pcp->count, pcp);
2821 local_irq_restore(flags);
2825 * Drain pcplists of all zones on the indicated processor.
2827 * The processor must either be the current processor and the
2828 * thread pinned to the current processor or a processor that
2831 static void drain_pages(unsigned int cpu)
2835 for_each_populated_zone(zone) {
2836 drain_pages_zone(cpu, zone);
2841 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
2843 * The CPU has to be pinned. When zone parameter is non-NULL, spill just
2844 * the single zone's pages.
2846 void drain_local_pages(struct zone *zone)
2848 int cpu = smp_processor_id();
2851 drain_pages_zone(cpu, zone);
2856 static void drain_local_pages_wq(struct work_struct *work)
2858 struct pcpu_drain *drain;
2860 drain = container_of(work, struct pcpu_drain, work);
2863 * drain_all_pages doesn't use proper cpu hotplug protection so
2864 * we can race with cpu offline when the WQ can move this from
2865 * a cpu pinned worker to an unbound one. We can operate on a different
2866 * cpu which is allright but we also have to make sure to not move to
2870 drain_local_pages(drain->zone);
2875 * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
2877 * When zone parameter is non-NULL, spill just the single zone's pages.
2879 * Note that this can be extremely slow as the draining happens in a workqueue.
2881 void drain_all_pages(struct zone *zone)
2886 * Allocate in the BSS so we wont require allocation in
2887 * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
2889 static cpumask_t cpus_with_pcps;
2892 * Make sure nobody triggers this path before mm_percpu_wq is fully
2895 if (WARN_ON_ONCE(!mm_percpu_wq))
2899 * Do not drain if one is already in progress unless it's specific to
2900 * a zone. Such callers are primarily CMA and memory hotplug and need
2901 * the drain to be complete when the call returns.
2903 if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) {
2906 mutex_lock(&pcpu_drain_mutex);
2910 * We don't care about racing with CPU hotplug event
2911 * as offline notification will cause the notified
2912 * cpu to drain that CPU pcps and on_each_cpu_mask
2913 * disables preemption as part of its processing
2915 for_each_online_cpu(cpu) {
2916 struct per_cpu_pageset *pcp;
2918 bool has_pcps = false;
2921 pcp = per_cpu_ptr(zone->pageset, cpu);
2925 for_each_populated_zone(z) {
2926 pcp = per_cpu_ptr(z->pageset, cpu);
2927 if (pcp->pcp.count) {
2935 cpumask_set_cpu(cpu, &cpus_with_pcps);
2937 cpumask_clear_cpu(cpu, &cpus_with_pcps);
2940 for_each_cpu(cpu, &cpus_with_pcps) {
2941 struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu);
2944 INIT_WORK(&drain->work, drain_local_pages_wq);
2945 queue_work_on(cpu, mm_percpu_wq, &drain->work);
2947 for_each_cpu(cpu, &cpus_with_pcps)
2948 flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work);
2950 mutex_unlock(&pcpu_drain_mutex);
2953 #ifdef CONFIG_HIBERNATION
2956 * Touch the watchdog for every WD_PAGE_COUNT pages.
2958 #define WD_PAGE_COUNT (128*1024)
2960 void mark_free_pages(struct zone *zone)
2962 unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
2963 unsigned long flags;
2964 unsigned int order, t;
2967 if (zone_is_empty(zone))
2970 spin_lock_irqsave(&zone->lock, flags);
2972 max_zone_pfn = zone_end_pfn(zone);
2973 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
2974 if (pfn_valid(pfn)) {
2975 page = pfn_to_page(pfn);
2977 if (!--page_count) {
2978 touch_nmi_watchdog();
2979 page_count = WD_PAGE_COUNT;
2982 if (page_zone(page) != zone)
2985 if (!swsusp_page_is_forbidden(page))
2986 swsusp_unset_page_free(page);
2989 for_each_migratetype_order(order, t) {
2990 list_for_each_entry(page,
2991 &zone->free_area[order].free_list[t], lru) {
2994 pfn = page_to_pfn(page);
2995 for (i = 0; i < (1UL << order); i++) {
2996 if (!--page_count) {
2997 touch_nmi_watchdog();
2998 page_count = WD_PAGE_COUNT;
3000 swsusp_set_page_free(pfn_to_page(pfn + i));
3004 spin_unlock_irqrestore(&zone->lock, flags);
3006 #endif /* CONFIG_PM */
3008 static bool free_unref_page_prepare(struct page *page, unsigned long pfn)
3012 if (!free_pcp_prepare(page))
3015 migratetype = get_pfnblock_migratetype(page, pfn);
3016 set_pcppage_migratetype(page, migratetype);
3020 static void free_unref_page_commit(struct page *page, unsigned long pfn)
3022 struct zone *zone = page_zone(page);
3023 struct per_cpu_pages *pcp;
3026 migratetype = get_pcppage_migratetype(page);
3027 __count_vm_event(PGFREE);
3030 * We only track unmovable, reclaimable and movable on pcp lists.
3031 * Free ISOLATE pages back to the allocator because they are being
3032 * offlined but treat HIGHATOMIC as movable pages so we can get those
3033 * areas back if necessary. Otherwise, we may have to free
3034 * excessively into the page allocator
3036 if (migratetype >= MIGRATE_PCPTYPES) {
3037 if (unlikely(is_migrate_isolate(migratetype))) {
3038 free_one_page(zone, page, pfn, 0, migratetype);
3041 migratetype = MIGRATE_MOVABLE;
3044 pcp = &this_cpu_ptr(zone->pageset)->pcp;
3045 list_add(&page->lru, &pcp->lists[migratetype]);
3047 if (pcp->count >= pcp->high) {
3048 unsigned long batch = READ_ONCE(pcp->batch);
3049 free_pcppages_bulk(zone, batch, pcp);
3054 * Free a 0-order page
3056 void free_unref_page(struct page *page)
3058 unsigned long flags;
3059 unsigned long pfn = page_to_pfn(page);
3061 if (!free_unref_page_prepare(page, pfn))
3064 local_irq_save(flags);
3065 free_unref_page_commit(page, pfn);
3066 local_irq_restore(flags);
3070 * Free a list of 0-order pages
3072 void free_unref_page_list(struct list_head *list)
3074 struct page *page, *next;
3075 unsigned long flags, pfn;
3076 int batch_count = 0;
3078 /* Prepare pages for freeing */
3079 list_for_each_entry_safe(page, next, list, lru) {
3080 pfn = page_to_pfn(page);
3081 if (!free_unref_page_prepare(page, pfn))
3082 list_del(&page->lru);
3083 set_page_private(page, pfn);
3086 local_irq_save(flags);
3087 list_for_each_entry_safe(page, next, list, lru) {
3088 unsigned long pfn = page_private(page);
3090 set_page_private(page, 0);
3091 trace_mm_page_free_batched(page);
3092 free_unref_page_commit(page, pfn);
3095 * Guard against excessive IRQ disabled times when we get
3096 * a large list of pages to free.
3098 if (++batch_count == SWAP_CLUSTER_MAX) {
3099 local_irq_restore(flags);
3101 local_irq_save(flags);
3104 local_irq_restore(flags);
3108 * split_page takes a non-compound higher-order page, and splits it into
3109 * n (1<<order) sub-pages: page[0..n]
3110 * Each sub-page must be freed individually.
3112 * Note: this is probably too low level an operation for use in drivers.
3113 * Please consult with lkml before using this in your driver.
3115 void split_page(struct page *page, unsigned int order)
3119 VM_BUG_ON_PAGE(PageCompound(page), page);
3120 VM_BUG_ON_PAGE(!page_count(page), page);
3122 for (i = 1; i < (1 << order); i++)
3123 set_page_refcounted(page + i);
3124 split_page_owner(page, order);
3126 EXPORT_SYMBOL_GPL(split_page);
3128 int __isolate_free_page(struct page *page, unsigned int order)
3130 struct free_area *area = &page_zone(page)->free_area[order];
3131 unsigned long watermark;
3135 BUG_ON(!PageBuddy(page));
3137 zone = page_zone(page);
3138 mt = get_pageblock_migratetype(page);
3140 if (!is_migrate_isolate(mt)) {
3142 * Obey watermarks as if the page was being allocated. We can
3143 * emulate a high-order watermark check with a raised order-0
3144 * watermark, because we already know our high-order page
3147 watermark = zone->_watermark[WMARK_MIN] + (1UL << order);
3148 if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
3151 __mod_zone_freepage_state(zone, -(1UL << order), mt);
3154 /* Remove page from free list */
3156 del_page_from_free_area(page, area);
3159 * Set the pageblock if the isolated page is at least half of a
3162 if (order >= pageblock_order - 1) {
3163 struct page *endpage = page + (1 << order) - 1;
3164 for (; page < endpage; page += pageblock_nr_pages) {
3165 int mt = get_pageblock_migratetype(page);
3166 if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
3167 && !is_migrate_highatomic(mt))
3168 set_pageblock_migratetype(page,
3174 return 1UL << order;
3178 * Update NUMA hit/miss statistics
3180 * Must be called with interrupts disabled.
3182 static inline void zone_statistics(struct zone *preferred_zone, struct zone *z)
3185 enum numa_stat_item local_stat = NUMA_LOCAL;
3187 /* skip numa counters update if numa stats is disabled */
3188 if (!static_branch_likely(&vm_numa_stat_key))
3191 if (zone_to_nid(z) != numa_node_id())
3192 local_stat = NUMA_OTHER;
3194 if (zone_to_nid(z) == zone_to_nid(preferred_zone))
3195 __inc_numa_state(z, NUMA_HIT);
3197 __inc_numa_state(z, NUMA_MISS);
3198 __inc_numa_state(preferred_zone, NUMA_FOREIGN);
3200 __inc_numa_state(z, local_stat);
3204 /* Remove page from the per-cpu list, caller must protect the list */
3205 static struct page *__rmqueue_pcplist(struct zone *zone, int migratetype,
3206 unsigned int alloc_flags,
3207 struct per_cpu_pages *pcp,
3208 struct list_head *list)
3213 if (list_empty(list)) {
3214 pcp->count += rmqueue_bulk(zone, 0,
3216 migratetype, alloc_flags);
3217 if (unlikely(list_empty(list)))
3221 page = list_first_entry(list, struct page, lru);
3222 list_del(&page->lru);
3224 } while (check_new_pcp(page));
3229 /* Lock and remove page from the per-cpu list */
3230 static struct page *rmqueue_pcplist(struct zone *preferred_zone,
3231 struct zone *zone, gfp_t gfp_flags,
3232 int migratetype, unsigned int alloc_flags)
3234 struct per_cpu_pages *pcp;
3235 struct list_head *list;
3237 unsigned long flags;
3239 local_irq_save(flags);
3240 pcp = &this_cpu_ptr(zone->pageset)->pcp;
3241 list = &pcp->lists[migratetype];
3242 page = __rmqueue_pcplist(zone, migratetype, alloc_flags, pcp, list);
3244 __count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
3245 zone_statistics(preferred_zone, zone);
3247 local_irq_restore(flags);
3252 * Allocate a page from the given zone. Use pcplists for order-0 allocations.
3255 struct page *rmqueue(struct zone *preferred_zone,
3256 struct zone *zone, unsigned int order,
3257 gfp_t gfp_flags, unsigned int alloc_flags,
3260 unsigned long flags;
3263 if (likely(order == 0)) {
3264 page = rmqueue_pcplist(preferred_zone, zone, gfp_flags,
3265 migratetype, alloc_flags);
3270 * We most definitely don't want callers attempting to
3271 * allocate greater than order-1 page units with __GFP_NOFAIL.
3273 WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
3274 spin_lock_irqsave(&zone->lock, flags);
3278 if (alloc_flags & ALLOC_HARDER) {
3279 page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
3281 trace_mm_page_alloc_zone_locked(page, order, migratetype);
3284 page = __rmqueue(zone, order, migratetype, alloc_flags);
3285 } while (page && check_new_pages(page, order));
3286 spin_unlock(&zone->lock);
3289 __mod_zone_freepage_state(zone, -(1 << order),
3290 get_pcppage_migratetype(page));
3292 __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
3293 zone_statistics(preferred_zone, zone);
3294 local_irq_restore(flags);
3297 /* Separate test+clear to avoid unnecessary atomics */
3298 if (test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags)) {
3299 clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
3300 wakeup_kswapd(zone, 0, 0, zone_idx(zone));
3303 VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
3307 local_irq_restore(flags);
3311 #ifdef CONFIG_FAIL_PAGE_ALLOC
3314 struct fault_attr attr;
3316 bool ignore_gfp_highmem;
3317 bool ignore_gfp_reclaim;
3319 } fail_page_alloc = {
3320 .attr = FAULT_ATTR_INITIALIZER,
3321 .ignore_gfp_reclaim = true,
3322 .ignore_gfp_highmem = true,
3326 static int __init setup_fail_page_alloc(char *str)
3328 return setup_fault_attr(&fail_page_alloc.attr, str);
3330 __setup("fail_page_alloc=", setup_fail_page_alloc);
3332 static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3334 if (order < fail_page_alloc.min_order)
3336 if (gfp_mask & __GFP_NOFAIL)
3338 if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
3340 if (fail_page_alloc.ignore_gfp_reclaim &&
3341 (gfp_mask & __GFP_DIRECT_RECLAIM))
3344 return should_fail(&fail_page_alloc.attr, 1 << order);
3347 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
3349 static int __init fail_page_alloc_debugfs(void)
3351 umode_t mode = S_IFREG | 0600;
3354 dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
3355 &fail_page_alloc.attr);
3357 debugfs_create_bool("ignore-gfp-wait", mode, dir,
3358 &fail_page_alloc.ignore_gfp_reclaim);
3359 debugfs_create_bool("ignore-gfp-highmem", mode, dir,
3360 &fail_page_alloc.ignore_gfp_highmem);
3361 debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);
3366 late_initcall(fail_page_alloc_debugfs);
3368 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
3370 #else /* CONFIG_FAIL_PAGE_ALLOC */
3372 static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3377 #endif /* CONFIG_FAIL_PAGE_ALLOC */
3379 static noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3381 return __should_fail_alloc_page(gfp_mask, order);
3383 ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);
3386 * Return true if free base pages are above 'mark'. For high-order checks it
3387 * will return true of the order-0 watermark is reached and there is at least
3388 * one free page of a suitable size. Checking now avoids taking the zone lock
3389 * to check in the allocation paths if no pages are free.
3391 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
3392 int classzone_idx, unsigned int alloc_flags,
3397 const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM));
3399 /* free_pages may go negative - that's OK */
3400 free_pages -= (1 << order) - 1;
3402 if (alloc_flags & ALLOC_HIGH)
3406 * If the caller does not have rights to ALLOC_HARDER then subtract
3407 * the high-atomic reserves. This will over-estimate the size of the
3408 * atomic reserve but it avoids a search.
3410 if (likely(!alloc_harder)) {
3411 free_pages -= z->nr_reserved_highatomic;
3414 * OOM victims can try even harder than normal ALLOC_HARDER
3415 * users on the grounds that it's definitely going to be in
3416 * the exit path shortly and free memory. Any allocation it
3417 * makes during the free path will be small and short-lived.
3419 if (alloc_flags & ALLOC_OOM)
3427 /* If allocation can't use CMA areas don't use free CMA pages */
3428 if (!(alloc_flags & ALLOC_CMA))
3429 free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
3433 * Check watermarks for an order-0 allocation request. If these
3434 * are not met, then a high-order request also cannot go ahead
3435 * even if a suitable page happened to be free.
3437 if (free_pages <= min + z->lowmem_reserve[classzone_idx])
3440 /* If this is an order-0 request then the watermark is fine */
3444 /* For a high-order request, check at least one suitable page is free */
3445 for (o = order; o < MAX_ORDER; o++) {
3446 struct free_area *area = &z->free_area[o];
3452 for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
3453 if (!free_area_empty(area, mt))
3458 if ((alloc_flags & ALLOC_CMA) &&
3459 !free_area_empty(area, MIGRATE_CMA)) {
3464 !list_empty(&area->free_list[MIGRATE_HIGHATOMIC]))
3470 bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
3471 int classzone_idx, unsigned int alloc_flags)
3473 return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
3474 zone_page_state(z, NR_FREE_PAGES));
3477 static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
3478 unsigned long mark, int classzone_idx, unsigned int alloc_flags)
3480 long free_pages = zone_page_state(z, NR_FREE_PAGES);
3484 /* If allocation can't use CMA areas don't use free CMA pages */
3485 if (!(alloc_flags & ALLOC_CMA))
3486 cma_pages = zone_page_state(z, NR_FREE_CMA_PAGES);
3490 * Fast check for order-0 only. If this fails then the reserves
3491 * need to be calculated. There is a corner case where the check
3492 * passes but only the high-order atomic reserve are free. If
3493 * the caller is !atomic then it'll uselessly search the free
3494 * list. That corner case is then slower but it is harmless.
3496 if (!order && (free_pages - cma_pages) > mark + z->lowmem_reserve[classzone_idx])
3499 return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
3503 bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
3504 unsigned long mark, int classzone_idx)
3506 long free_pages = zone_page_state(z, NR_FREE_PAGES);
3508 if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
3509 free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
3511 return __zone_watermark_ok(z, order, mark, classzone_idx, 0,
3516 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
3518 return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <=
3519 node_reclaim_distance;
3521 #else /* CONFIG_NUMA */
3522 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
3526 #endif /* CONFIG_NUMA */
3529 * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid
3530 * fragmentation is subtle. If the preferred zone was HIGHMEM then
3531 * premature use of a lower zone may cause lowmem pressure problems that
3532 * are worse than fragmentation. If the next zone is ZONE_DMA then it is
3533 * probably too small. It only makes sense to spread allocations to avoid
3534 * fragmentation between the Normal and DMA32 zones.
3536 static inline unsigned int
3537 alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
3539 unsigned int alloc_flags;
3542 * __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
3545 alloc_flags = (__force int) (gfp_mask & __GFP_KSWAPD_RECLAIM);
3547 #ifdef CONFIG_ZONE_DMA32
3551 if (zone_idx(zone) != ZONE_NORMAL)
3555 * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and
3556 * the pointer is within zone->zone_pgdat->node_zones[]. Also assume
3557 * on UMA that if Normal is populated then so is DMA32.
3559 BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1);
3560 if (nr_online_nodes > 1 && !populated_zone(--zone))
3563 alloc_flags |= ALLOC_NOFRAGMENT;
3564 #endif /* CONFIG_ZONE_DMA32 */
3569 * get_page_from_freelist goes through the zonelist trying to allocate
3572 static struct page *
3573 get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
3574 const struct alloc_context *ac)
3578 struct pglist_data *last_pgdat_dirty_limit = NULL;
3583 * Scan zonelist, looking for a zone with enough free.
3584 * See also __cpuset_node_allowed() comment in kernel/cpuset.c.
3586 no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
3587 z = ac->preferred_zoneref;
3588 for_next_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
3593 if (cpusets_enabled() &&
3594 (alloc_flags & ALLOC_CPUSET) &&
3595 !__cpuset_zone_allowed(zone, gfp_mask))
3598 * When allocating a page cache page for writing, we
3599 * want to get it from a node that is within its dirty
3600 * limit, such that no single node holds more than its
3601 * proportional share of globally allowed dirty pages.
3602 * The dirty limits take into account the node's
3603 * lowmem reserves and high watermark so that kswapd
3604 * should be able to balance it without having to
3605 * write pages from its LRU list.
3607 * XXX: For now, allow allocations to potentially
3608 * exceed the per-node dirty limit in the slowpath
3609 * (spread_dirty_pages unset) before going into reclaim,
3610 * which is important when on a NUMA setup the allowed
3611 * nodes are together not big enough to reach the
3612 * global limit. The proper fix for these situations
3613 * will require awareness of nodes in the
3614 * dirty-throttling and the flusher threads.
3616 if (ac->spread_dirty_pages) {
3617 if (last_pgdat_dirty_limit == zone->zone_pgdat)
3620 if (!node_dirty_ok(zone->zone_pgdat)) {
3621 last_pgdat_dirty_limit = zone->zone_pgdat;
3626 if (no_fallback && nr_online_nodes > 1 &&
3627 zone != ac->preferred_zoneref->zone) {
3631 * If moving to a remote node, retry but allow
3632 * fragmenting fallbacks. Locality is more important
3633 * than fragmentation avoidance.
3635 local_nid = zone_to_nid(ac->preferred_zoneref->zone);
3636 if (zone_to_nid(zone) != local_nid) {
3637 alloc_flags &= ~ALLOC_NOFRAGMENT;
3642 mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
3643 if (!zone_watermark_fast(zone, order, mark,
3644 ac_classzone_idx(ac), alloc_flags)) {
3647 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
3649 * Watermark failed for this zone, but see if we can
3650 * grow this zone if it contains deferred pages.
3652 if (static_branch_unlikely(&deferred_pages)) {
3653 if (_deferred_grow_zone(zone, order))
3657 /* Checked here to keep the fast path fast */
3658 BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
3659 if (alloc_flags & ALLOC_NO_WATERMARKS)
3662 if (node_reclaim_mode == 0 ||
3663 !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
3666 ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
3668 case NODE_RECLAIM_NOSCAN:
3671 case NODE_RECLAIM_FULL:
3672 /* scanned but unreclaimable */
3675 /* did we reclaim enough */
3676 if (zone_watermark_ok(zone, order, mark,
3677 ac_classzone_idx(ac), alloc_flags))
3685 page = rmqueue(ac->preferred_zoneref->zone, zone, order,
3686 gfp_mask, alloc_flags, ac->migratetype);
3688 prep_new_page(page, order, gfp_mask, alloc_flags);
3691 * If this is a high-order atomic allocation then check
3692 * if the pageblock should be reserved for the future
3694 if (unlikely(order && (alloc_flags & ALLOC_HARDER)))
3695 reserve_highatomic_pageblock(page, zone, order);
3699 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
3700 /* Try again if zone has deferred pages */
3701 if (static_branch_unlikely(&deferred_pages)) {
3702 if (_deferred_grow_zone(zone, order))
3710 * It's possible on a UMA machine to get through all zones that are
3711 * fragmented. If avoiding fragmentation, reset and try again.
3714 alloc_flags &= ~ALLOC_NOFRAGMENT;
3721 static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask)
3723 unsigned int filter = SHOW_MEM_FILTER_NODES;
3726 * This documents exceptions given to allocations in certain
3727 * contexts that are allowed to allocate outside current's set
3730 if (!(gfp_mask & __GFP_NOMEMALLOC))
3731 if (tsk_is_oom_victim(current) ||
3732 (current->flags & (PF_MEMALLOC | PF_EXITING)))
3733 filter &= ~SHOW_MEM_FILTER_NODES;
3734 if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
3735 filter &= ~SHOW_MEM_FILTER_NODES;
3737 show_mem(filter, nodemask);
3740 void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)
3742 struct va_format vaf;
3744 static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1);
3746 if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs))
3749 va_start(args, fmt);
3752 pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl",
3753 current->comm, &vaf, gfp_mask, &gfp_mask,
3754 nodemask_pr_args(nodemask));
3757 cpuset_print_current_mems_allowed();
3760 warn_alloc_show_mem(gfp_mask, nodemask);
3763 static inline struct page *
3764 __alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order,
3765 unsigned int alloc_flags,
3766 const struct alloc_context *ac)
3770 page = get_page_from_freelist(gfp_mask, order,
3771 alloc_flags|ALLOC_CPUSET, ac);
3773 * fallback to ignore cpuset restriction if our nodes
3777 page = get_page_from_freelist(gfp_mask, order,
3783 static inline struct page *
3784 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
3785 const struct alloc_context *ac, unsigned long *did_some_progress)
3787 struct oom_control oc = {
3788 .zonelist = ac->zonelist,
3789 .nodemask = ac->nodemask,
3791 .gfp_mask = gfp_mask,
3796 *did_some_progress = 0;
3799 * Acquire the oom lock. If that fails, somebody else is
3800 * making progress for us.
3802 if (!mutex_trylock(&oom_lock)) {
3803 *did_some_progress = 1;
3804 schedule_timeout_uninterruptible(1);
3809 * Go through the zonelist yet one more time, keep very high watermark
3810 * here, this is only to catch a parallel oom killing, we must fail if
3811 * we're still under heavy pressure. But make sure that this reclaim
3812 * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY
3813 * allocation which will never fail due to oom_lock already held.
3815 page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) &
3816 ~__GFP_DIRECT_RECLAIM, order,
3817 ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
3821 /* Coredumps can quickly deplete all memory reserves */
3822 if (current->flags & PF_DUMPCORE)
3824 /* The OOM killer will not help higher order allocs */
3825 if (order > PAGE_ALLOC_COSTLY_ORDER)
3828 * We have already exhausted all our reclaim opportunities without any
3829 * success so it is time to admit defeat. We will skip the OOM killer
3830 * because it is very likely that the caller has a more reasonable
3831 * fallback than shooting a random task.
3833 if (gfp_mask & __GFP_RETRY_MAYFAIL)
3835 /* The OOM killer does not needlessly kill tasks for lowmem */
3836 if (ac->high_zoneidx < ZONE_NORMAL)
3838 if (pm_suspended_storage())
3841 * XXX: GFP_NOFS allocations should rather fail than rely on
3842 * other request to make a forward progress.
3843 * We are in an unfortunate situation where out_of_memory cannot
3844 * do much for this context but let's try it to at least get
3845 * access to memory reserved if the current task is killed (see
3846 * out_of_memory). Once filesystems are ready to handle allocation
3847 * failures more gracefully we should just bail out here.
3850 /* The OOM killer may not free memory on a specific node */
3851 if (gfp_mask & __GFP_THISNODE)
3854 /* Exhausted what can be done so it's blame time */
3855 if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
3856 *did_some_progress = 1;
3859 * Help non-failing allocations by giving them access to memory
3862 if (gfp_mask & __GFP_NOFAIL)
3863 page = __alloc_pages_cpuset_fallback(gfp_mask, order,
3864 ALLOC_NO_WATERMARKS, ac);
3867 mutex_unlock(&oom_lock);
3872 * Maximum number of compaction retries wit a progress before OOM
3873 * killer is consider as the only way to move forward.
3875 #define MAX_COMPACT_RETRIES 16
3877 #ifdef CONFIG_COMPACTION
3878 /* Try memory compaction for high-order allocations before reclaim */
3879 static struct page *
3880 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
3881 unsigned int alloc_flags, const struct alloc_context *ac,
3882 enum compact_priority prio, enum compact_result *compact_result)
3884 struct page *page = NULL;
3885 unsigned long pflags;
3886 unsigned int noreclaim_flag;
3891 psi_memstall_enter(&pflags);
3892 noreclaim_flag = memalloc_noreclaim_save();
3894 *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
3897 memalloc_noreclaim_restore(noreclaim_flag);
3898 psi_memstall_leave(&pflags);
3901 * At least in one zone compaction wasn't deferred or skipped, so let's
3902 * count a compaction stall
3904 count_vm_event(COMPACTSTALL);
3906 /* Prep a captured page if available */
3908 prep_new_page(page, order, gfp_mask, alloc_flags);
3910 /* Try get a page from the freelist if available */
3912 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3915 struct zone *zone = page_zone(page);
3917 zone->compact_blockskip_flush = false;
3918 compaction_defer_reset(zone, order, true);
3919 count_vm_event(COMPACTSUCCESS);
3924 * It's bad if compaction run occurs and fails. The most likely reason
3925 * is that pages exist, but not enough to satisfy watermarks.
3927 count_vm_event(COMPACTFAIL);
3935 should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
3936 enum compact_result compact_result,
3937 enum compact_priority *compact_priority,
3938 int *compaction_retries)
3940 int max_retries = MAX_COMPACT_RETRIES;
3943 int retries = *compaction_retries;
3944 enum compact_priority priority = *compact_priority;
3949 if (compaction_made_progress(compact_result))
3950 (*compaction_retries)++;
3953 * compaction considers all the zone as desperately out of memory
3954 * so it doesn't really make much sense to retry except when the
3955 * failure could be caused by insufficient priority
3957 if (compaction_failed(compact_result))
3958 goto check_priority;
3961 * compaction was skipped because there are not enough order-0 pages
3962 * to work with, so we retry only if it looks like reclaim can help.
3964 if (compaction_needs_reclaim(compact_result)) {
3965 ret = compaction_zonelist_suitable(ac, order, alloc_flags);
3970 * make sure the compaction wasn't deferred or didn't bail out early
3971 * due to locks contention before we declare that we should give up.
3972 * But the next retry should use a higher priority if allowed, so
3973 * we don't just keep bailing out endlessly.
3975 if (compaction_withdrawn(compact_result)) {
3976 goto check_priority;
3980 * !costly requests are much more important than __GFP_RETRY_MAYFAIL
3981 * costly ones because they are de facto nofail and invoke OOM
3982 * killer to move on while costly can fail and users are ready
3983 * to cope with that. 1/4 retries is rather arbitrary but we
3984 * would need much more detailed feedback from compaction to
3985 * make a better decision.
3987 if (order > PAGE_ALLOC_COSTLY_ORDER)
3989 if (*compaction_retries <= max_retries) {
3995 * Make sure there are attempts at the highest priority if we exhausted
3996 * all retries or failed at the lower priorities.
3999 min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ?
4000 MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;
4002 if (*compact_priority > min_priority) {
4003 (*compact_priority)--;
4004 *compaction_retries = 0;
4008 trace_compact_retry(order, priority, compact_result, retries, max_retries, ret);
4012 static inline struct page *
4013 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
4014 unsigned int alloc_flags, const struct alloc_context *ac,
4015 enum compact_priority prio, enum compact_result *compact_result)
4017 *compact_result = COMPACT_SKIPPED;
4022 should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
4023 enum compact_result compact_result,
4024 enum compact_priority *compact_priority,
4025 int *compaction_retries)
4030 if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
4034 * There are setups with compaction disabled which would prefer to loop
4035 * inside the allocator rather than hit the oom killer prematurely.
4036 * Let's give them a good hope and keep retrying while the order-0
4037 * watermarks are OK.
4039 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
4041 if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
4042 ac_classzone_idx(ac), alloc_flags))
4047 #endif /* CONFIG_COMPACTION */
4049 #ifdef CONFIG_LOCKDEP
4050 static struct lockdep_map __fs_reclaim_map =
4051 STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map);
4053 static bool __need_fs_reclaim(gfp_t gfp_mask)
4055 gfp_mask = current_gfp_context(gfp_mask);
4057 /* no reclaim without waiting on it */
4058 if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
4061 /* this guy won't enter reclaim */
4062 if (current->flags & PF_MEMALLOC)
4065 /* We're only interested __GFP_FS allocations for now */
4066 if (!(gfp_mask & __GFP_FS))
4069 if (gfp_mask & __GFP_NOLOCKDEP)
4075 void __fs_reclaim_acquire(void)
4077 lock_map_acquire(&__fs_reclaim_map);
4080 void __fs_reclaim_release(void)
4082 lock_map_release(&__fs_reclaim_map);
4085 void fs_reclaim_acquire(gfp_t gfp_mask)
4087 if (__need_fs_reclaim(gfp_mask))
4088 __fs_reclaim_acquire();
4090 EXPORT_SYMBOL_GPL(fs_reclaim_acquire);
4092 void fs_reclaim_release(gfp_t gfp_mask)
4094 if (__need_fs_reclaim(gfp_mask))
4095 __fs_reclaim_release();
4097 EXPORT_SYMBOL_GPL(fs_reclaim_release);
4100 /* Perform direct synchronous page reclaim */
4102 __perform_reclaim(gfp_t gfp_mask, unsigned int order,
4103 const struct alloc_context *ac)
4106 unsigned int noreclaim_flag;
4107 unsigned long pflags;
4111 /* We now go into synchronous reclaim */
4112 cpuset_memory_pressure_bump();
4113 psi_memstall_enter(&pflags);
4114 fs_reclaim_acquire(gfp_mask);
4115 noreclaim_flag = memalloc_noreclaim_save();
4117 progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
4120 memalloc_noreclaim_restore(noreclaim_flag);
4121 fs_reclaim_release(gfp_mask);
4122 psi_memstall_leave(&pflags);
4129 /* The really slow allocator path where we enter direct reclaim */
4130 static inline struct page *
4131 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
4132 unsigned int alloc_flags, const struct alloc_context *ac,
4133 unsigned long *did_some_progress)
4135 struct page *page = NULL;
4136 bool drained = false;
4138 *did_some_progress = __perform_reclaim(gfp_mask, order, ac);
4139 if (unlikely(!(*did_some_progress)))
4143 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4146 * If an allocation failed after direct reclaim, it could be because
4147 * pages are pinned on the per-cpu lists or in high alloc reserves.
4148 * Shrink them them and try again
4150 if (!page && !drained) {
4151 unreserve_highatomic_pageblock(ac, false);
4152 drain_all_pages(NULL);
4160 static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
4161 const struct alloc_context *ac)
4165 pg_data_t *last_pgdat = NULL;
4166 enum zone_type high_zoneidx = ac->high_zoneidx;
4168 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, high_zoneidx,
4170 if (last_pgdat != zone->zone_pgdat)
4171 wakeup_kswapd(zone, gfp_mask, order, high_zoneidx);
4172 last_pgdat = zone->zone_pgdat;
4176 static inline unsigned int
4177 gfp_to_alloc_flags(gfp_t gfp_mask)
4179 unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
4182 * __GFP_HIGH is assumed to be the same as ALLOC_HIGH
4183 * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
4184 * to save two branches.
4186 BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
4187 BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD);
4190 * The caller may dip into page reserves a bit more if the caller
4191 * cannot run direct reclaim, or if the caller has realtime scheduling
4192 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
4193 * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
4195 alloc_flags |= (__force int)
4196 (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM));
4198 if (gfp_mask & __GFP_ATOMIC) {
4200 * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
4201 * if it can't schedule.
4203 if (!(gfp_mask & __GFP_NOMEMALLOC))
4204 alloc_flags |= ALLOC_HARDER;
4206 * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
4207 * comment for __cpuset_node_allowed().
4209 alloc_flags &= ~ALLOC_CPUSET;
4210 } else if (unlikely(rt_task(current)) && !in_interrupt())
4211 alloc_flags |= ALLOC_HARDER;
4214 if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
4215 alloc_flags |= ALLOC_CMA;
4220 static bool oom_reserves_allowed(struct task_struct *tsk)
4222 if (!tsk_is_oom_victim(tsk))
4226 * !MMU doesn't have oom reaper so give access to memory reserves
4227 * only to the thread with TIF_MEMDIE set
4229 if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE))
4236 * Distinguish requests which really need access to full memory
4237 * reserves from oom victims which can live with a portion of it
4239 static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask)
4241 if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
4243 if (gfp_mask & __GFP_MEMALLOC)
4244 return ALLOC_NO_WATERMARKS;
4245 if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
4246 return ALLOC_NO_WATERMARKS;
4247 if (!in_interrupt()) {
4248 if (current->flags & PF_MEMALLOC)
4249 return ALLOC_NO_WATERMARKS;
4250 else if (oom_reserves_allowed(current))
4257 bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
4259 return !!__gfp_pfmemalloc_flags(gfp_mask);
4263 * Checks whether it makes sense to retry the reclaim to make a forward progress
4264 * for the given allocation request.
4266 * We give up when we either have tried MAX_RECLAIM_RETRIES in a row
4267 * without success, or when we couldn't even meet the watermark if we
4268 * reclaimed all remaining pages on the LRU lists.
4270 * Returns true if a retry is viable or false to enter the oom path.
4273 should_reclaim_retry(gfp_t gfp_mask, unsigned order,
4274 struct alloc_context *ac, int alloc_flags,
4275 bool did_some_progress, int *no_progress_loops)
4282 * Costly allocations might have made a progress but this doesn't mean
4283 * their order will become available due to high fragmentation so
4284 * always increment the no progress counter for them
4286 if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
4287 *no_progress_loops = 0;
4289 (*no_progress_loops)++;
4292 * Make sure we converge to OOM if we cannot make any progress
4293 * several times in the row.
4295 if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
4296 /* Before OOM, exhaust highatomic_reserve */
4297 return unreserve_highatomic_pageblock(ac, true);
4301 * Keep reclaiming pages while there is a chance this will lead
4302 * somewhere. If none of the target zones can satisfy our allocation
4303 * request even if all reclaimable pages are considered then we are
4304 * screwed and have to go OOM.
4306 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
4308 unsigned long available;
4309 unsigned long reclaimable;
4310 unsigned long min_wmark = min_wmark_pages(zone);
4313 available = reclaimable = zone_reclaimable_pages(zone);
4314 available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
4317 * Would the allocation succeed if we reclaimed all
4318 * reclaimable pages?
4320 wmark = __zone_watermark_ok(zone, order, min_wmark,
4321 ac_classzone_idx(ac), alloc_flags, available);
4322 trace_reclaim_retry_zone(z, order, reclaimable,
4323 available, min_wmark, *no_progress_loops, wmark);
4326 * If we didn't make any progress and have a lot of
4327 * dirty + writeback pages then we should wait for
4328 * an IO to complete to slow down the reclaim and
4329 * prevent from pre mature OOM
4331 if (!did_some_progress) {
4332 unsigned long write_pending;
4334 write_pending = zone_page_state_snapshot(zone,
4335 NR_ZONE_WRITE_PENDING);
4337 if (2 * write_pending > reclaimable) {
4338 congestion_wait(BLK_RW_ASYNC, HZ/10);
4350 * Memory allocation/reclaim might be called from a WQ context and the
4351 * current implementation of the WQ concurrency control doesn't
4352 * recognize that a particular WQ is congested if the worker thread is
4353 * looping without ever sleeping. Therefore we have to do a short sleep
4354 * here rather than calling cond_resched().
4356 if (current->flags & PF_WQ_WORKER)
4357 schedule_timeout_uninterruptible(1);
4364 check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac)
4367 * It's possible that cpuset's mems_allowed and the nodemask from
4368 * mempolicy don't intersect. This should be normally dealt with by
4369 * policy_nodemask(), but it's possible to race with cpuset update in
4370 * such a way the check therein was true, and then it became false
4371 * before we got our cpuset_mems_cookie here.
4372 * This assumes that for all allocations, ac->nodemask can come only
4373 * from MPOL_BIND mempolicy (whose documented semantics is to be ignored
4374 * when it does not intersect with the cpuset restrictions) or the
4375 * caller can deal with a violated nodemask.
4377 if (cpusets_enabled() && ac->nodemask &&
4378 !cpuset_nodemask_valid_mems_allowed(ac->nodemask)) {
4379 ac->nodemask = NULL;
4384 * When updating a task's mems_allowed or mempolicy nodemask, it is
4385 * possible to race with parallel threads in such a way that our
4386 * allocation can fail while the mask is being updated. If we are about
4387 * to fail, check if the cpuset changed during allocation and if so,
4390 if (read_mems_allowed_retry(cpuset_mems_cookie))
4396 static inline struct page *
4397 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
4398 struct alloc_context *ac)
4400 bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
4401 const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER;
4402 struct page *page = NULL;
4403 unsigned int alloc_flags;
4404 unsigned long did_some_progress;
4405 enum compact_priority compact_priority;
4406 enum compact_result compact_result;
4407 int compaction_retries;
4408 int no_progress_loops;
4409 unsigned int cpuset_mems_cookie;
4413 * We also sanity check to catch abuse of atomic reserves being used by
4414 * callers that are not in atomic context.
4416 if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) ==
4417 (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
4418 gfp_mask &= ~__GFP_ATOMIC;
4421 compaction_retries = 0;
4422 no_progress_loops = 0;
4423 compact_priority = DEF_COMPACT_PRIORITY;
4424 cpuset_mems_cookie = read_mems_allowed_begin();
4427 * The fast path uses conservative alloc_flags to succeed only until
4428 * kswapd needs to be woken up, and to avoid the cost of setting up
4429 * alloc_flags precisely. So we do that now.
4431 alloc_flags = gfp_to_alloc_flags(gfp_mask);
4434 * We need to recalculate the starting point for the zonelist iterator
4435 * because we might have used different nodemask in the fast path, or
4436 * there was a cpuset modification and we are retrying - otherwise we
4437 * could end up iterating over non-eligible zones endlessly.
4439 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4440 ac->high_zoneidx, ac->nodemask);
4441 if (!ac->preferred_zoneref->zone)
4444 if (alloc_flags & ALLOC_KSWAPD)
4445 wake_all_kswapds(order, gfp_mask, ac);
4448 * The adjusted alloc_flags might result in immediate success, so try
4451 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4456 * For costly allocations, try direct compaction first, as it's likely
4457 * that we have enough base pages and don't need to reclaim. For non-
4458 * movable high-order allocations, do that as well, as compaction will
4459 * try prevent permanent fragmentation by migrating from blocks of the
4461 * Don't try this for allocations that are allowed to ignore
4462 * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen.
4464 if (can_direct_reclaim &&
4466 (order > 0 && ac->migratetype != MIGRATE_MOVABLE))
4467 && !gfp_pfmemalloc_allowed(gfp_mask)) {
4468 page = __alloc_pages_direct_compact(gfp_mask, order,
4470 INIT_COMPACT_PRIORITY,
4476 * Checks for costly allocations with __GFP_NORETRY, which
4477 * includes some THP page fault allocations
4479 if (costly_order && (gfp_mask & __GFP_NORETRY)) {
4481 * If allocating entire pageblock(s) and compaction
4482 * failed because all zones are below low watermarks
4483 * or is prohibited because it recently failed at this
4484 * order, fail immediately unless the allocator has
4485 * requested compaction and reclaim retry.
4488 * - potentially very expensive because zones are far
4489 * below their low watermarks or this is part of very
4490 * bursty high order allocations,
4491 * - not guaranteed to help because isolate_freepages()
4492 * may not iterate over freed pages as part of its
4494 * - unlikely to make entire pageblocks free on its
4497 if (compact_result == COMPACT_SKIPPED ||
4498 compact_result == COMPACT_DEFERRED)
4502 * Looks like reclaim/compaction is worth trying, but
4503 * sync compaction could be very expensive, so keep
4504 * using async compaction.
4506 compact_priority = INIT_COMPACT_PRIORITY;
4511 /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
4512 if (alloc_flags & ALLOC_KSWAPD)
4513 wake_all_kswapds(order, gfp_mask, ac);
4515 reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
4517 alloc_flags = reserve_flags;
4520 * Reset the nodemask and zonelist iterators if memory policies can be
4521 * ignored. These allocations are high priority and system rather than
4524 if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) {
4525 ac->nodemask = NULL;
4526 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4527 ac->high_zoneidx, ac->nodemask);
4530 /* Attempt with potentially adjusted zonelist and alloc_flags */
4531 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4535 /* Caller is not willing to reclaim, we can't balance anything */
4536 if (!can_direct_reclaim)
4539 /* Avoid recursion of direct reclaim */
4540 if (current->flags & PF_MEMALLOC)
4543 /* Try direct reclaim and then allocating */
4544 page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
4545 &did_some_progress);
4549 /* Try direct compaction and then allocating */
4550 page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
4551 compact_priority, &compact_result);
4555 /* Do not loop if specifically requested */
4556 if (gfp_mask & __GFP_NORETRY)
4560 * Do not retry costly high order allocations unless they are
4561 * __GFP_RETRY_MAYFAIL
4563 if (costly_order && !(gfp_mask & __GFP_RETRY_MAYFAIL))
4566 if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
4567 did_some_progress > 0, &no_progress_loops))
4571 * It doesn't make any sense to retry for the compaction if the order-0
4572 * reclaim is not able to make any progress because the current
4573 * implementation of the compaction depends on the sufficient amount
4574 * of free memory (see __compaction_suitable)
4576 if (did_some_progress > 0 &&
4577 should_compact_retry(ac, order, alloc_flags,
4578 compact_result, &compact_priority,
4579 &compaction_retries))
4583 /* Deal with possible cpuset update races before we start OOM killing */
4584 if (check_retry_cpuset(cpuset_mems_cookie, ac))
4587 /* Reclaim has failed us, start killing things */
4588 page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
4592 /* Avoid allocations with no watermarks from looping endlessly */
4593 if (tsk_is_oom_victim(current) &&
4594 (alloc_flags == ALLOC_OOM ||
4595 (gfp_mask & __GFP_NOMEMALLOC)))
4598 /* Retry as long as the OOM killer is making progress */
4599 if (did_some_progress) {
4600 no_progress_loops = 0;
4605 /* Deal with possible cpuset update races before we fail */
4606 if (check_retry_cpuset(cpuset_mems_cookie, ac))
4610 * Make sure that __GFP_NOFAIL request doesn't leak out and make sure
4613 if (gfp_mask & __GFP_NOFAIL) {
4615 * All existing users of the __GFP_NOFAIL are blockable, so warn
4616 * of any new users that actually require GFP_NOWAIT
4618 if (WARN_ON_ONCE(!can_direct_reclaim))
4622 * PF_MEMALLOC request from this context is rather bizarre
4623 * because we cannot reclaim anything and only can loop waiting
4624 * for somebody to do a work for us
4626 WARN_ON_ONCE(current->flags & PF_MEMALLOC);
4629 * non failing costly orders are a hard requirement which we
4630 * are not prepared for much so let's warn about these users
4631 * so that we can identify them and convert them to something
4634 WARN_ON_ONCE(order > PAGE_ALLOC_COSTLY_ORDER);
4637 * Help non-failing allocations by giving them access to memory
4638 * reserves but do not use ALLOC_NO_WATERMARKS because this
4639 * could deplete whole memory reserves which would just make
4640 * the situation worse
4642 page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_HARDER, ac);
4650 warn_alloc(gfp_mask, ac->nodemask,
4651 "page allocation failure: order:%u", order);
4656 static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
4657 int preferred_nid, nodemask_t *nodemask,
4658 struct alloc_context *ac, gfp_t *alloc_mask,
4659 unsigned int *alloc_flags)
4661 ac->high_zoneidx = gfp_zone(gfp_mask);
4662 ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
4663 ac->nodemask = nodemask;
4664 ac->migratetype = gfpflags_to_migratetype(gfp_mask);
4666 if (cpusets_enabled()) {
4667 *alloc_mask |= __GFP_HARDWALL;
4669 ac->nodemask = &cpuset_current_mems_allowed;
4671 *alloc_flags |= ALLOC_CPUSET;
4674 fs_reclaim_acquire(gfp_mask);
4675 fs_reclaim_release(gfp_mask);
4677 might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
4679 if (should_fail_alloc_page(gfp_mask, order))
4682 if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE)
4683 *alloc_flags |= ALLOC_CMA;
4688 /* Determine whether to spread dirty pages and what the first usable zone */
4689 static inline void finalise_ac(gfp_t gfp_mask, struct alloc_context *ac)
4691 /* Dirty zone balancing only done in the fast path */
4692 ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
4695 * The preferred zone is used for statistics but crucially it is
4696 * also used as the starting point for the zonelist iterator. It
4697 * may get reset for allocations that ignore memory policies.
4699 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4700 ac->high_zoneidx, ac->nodemask);
4704 * This is the 'heart' of the zoned buddy allocator.
4707 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
4708 nodemask_t *nodemask)
4711 unsigned int alloc_flags = ALLOC_WMARK_LOW;
4712 gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */
4713 struct alloc_context ac = { };
4716 * There are several places where we assume that the order value is sane
4717 * so bail out early if the request is out of bound.
4719 if (unlikely(order >= MAX_ORDER)) {
4720 WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
4724 gfp_mask &= gfp_allowed_mask;
4725 alloc_mask = gfp_mask;
4726 if (!prepare_alloc_pages(gfp_mask, order, preferred_nid, nodemask, &ac, &alloc_mask, &alloc_flags))
4729 finalise_ac(gfp_mask, &ac);
4732 * Forbid the first pass from falling back to types that fragment
4733 * memory until all local zones are considered.
4735 alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp_mask);
4737 /* First allocation attempt */
4738 page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
4743 * Apply scoped allocation constraints. This is mainly about GFP_NOFS
4744 * resp. GFP_NOIO which has to be inherited for all allocation requests
4745 * from a particular context which has been marked by
4746 * memalloc_no{fs,io}_{save,restore}.
4748 alloc_mask = current_gfp_context(gfp_mask);
4749 ac.spread_dirty_pages = false;
4752 * Restore the original nodemask if it was potentially replaced with
4753 * &cpuset_current_mems_allowed to optimize the fast-path attempt.
4755 if (unlikely(ac.nodemask != nodemask))
4756 ac.nodemask = nodemask;
4758 page = __alloc_pages_slowpath(alloc_mask, order, &ac);
4761 if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
4762 unlikely(__memcg_kmem_charge_page(page, gfp_mask, order) != 0)) {
4763 __free_pages(page, order);
4767 trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);
4771 EXPORT_SYMBOL(__alloc_pages_nodemask);
4774 * Common helper functions. Never use with __GFP_HIGHMEM because the returned
4775 * address cannot represent highmem pages. Use alloc_pages and then kmap if
4776 * you need to access high mem.
4778 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
4782 page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, order);
4785 return (unsigned long) page_address(page);
4787 EXPORT_SYMBOL(__get_free_pages);
4789 unsigned long get_zeroed_page(gfp_t gfp_mask)
4791 return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
4793 EXPORT_SYMBOL(get_zeroed_page);
4795 static inline void free_the_page(struct page *page, unsigned int order)
4797 if (order == 0) /* Via pcp? */
4798 free_unref_page(page);
4800 __free_pages_ok(page, order);
4803 void __free_pages(struct page *page, unsigned int order)
4805 if (put_page_testzero(page))
4806 free_the_page(page, order);
4808 EXPORT_SYMBOL(__free_pages);
4810 void free_pages(unsigned long addr, unsigned int order)
4813 VM_BUG_ON(!virt_addr_valid((void *)addr));
4814 __free_pages(virt_to_page((void *)addr), order);
4818 EXPORT_SYMBOL(free_pages);
4822 * An arbitrary-length arbitrary-offset area of memory which resides
4823 * within a 0 or higher order page. Multiple fragments within that page
4824 * are individually refcounted, in the page's reference counter.
4826 * The page_frag functions below provide a simple allocation framework for
4827 * page fragments. This is used by the network stack and network device
4828 * drivers to provide a backing region of memory for use as either an
4829 * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
4831 static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
4834 struct page *page = NULL;
4835 gfp_t gfp = gfp_mask;
4837 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4838 gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
4840 page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
4841 PAGE_FRAG_CACHE_MAX_ORDER);
4842 nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
4844 if (unlikely(!page))
4845 page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
4847 nc->va = page ? page_address(page) : NULL;
4852 void __page_frag_cache_drain(struct page *page, unsigned int count)
4854 VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
4856 if (page_ref_sub_and_test(page, count))
4857 free_the_page(page, compound_order(page));
4859 EXPORT_SYMBOL(__page_frag_cache_drain);
4861 void *page_frag_alloc(struct page_frag_cache *nc,
4862 unsigned int fragsz, gfp_t gfp_mask)
4864 unsigned int size = PAGE_SIZE;
4868 if (unlikely(!nc->va)) {
4870 page = __page_frag_cache_refill(nc, gfp_mask);
4874 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4875 /* if size can vary use size else just use PAGE_SIZE */
4878 /* Even if we own the page, we do not use atomic_set().
4879 * This would break get_page_unless_zero() users.
4881 page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE);
4883 /* reset page count bias and offset to start of new frag */
4884 nc->pfmemalloc = page_is_pfmemalloc(page);
4885 nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
4889 offset = nc->offset - fragsz;
4890 if (unlikely(offset < 0)) {
4891 page = virt_to_page(nc->va);
4893 if (!page_ref_sub_and_test(page, nc->pagecnt_bias))
4896 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4897 /* if size can vary use size else just use PAGE_SIZE */
4900 /* OK, page count is 0, we can safely set it */
4901 set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1);
4903 /* reset page count bias and offset to start of new frag */
4904 nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
4905 offset = size - fragsz;
4909 nc->offset = offset;
4911 return nc->va + offset;
4913 EXPORT_SYMBOL(page_frag_alloc);
4916 * Frees a page fragment allocated out of either a compound or order 0 page.
4918 void page_frag_free(void *addr)
4920 struct page *page = virt_to_head_page(addr);
4922 if (unlikely(put_page_testzero(page)))
4923 free_the_page(page, compound_order(page));
4925 EXPORT_SYMBOL(page_frag_free);
4927 static void *make_alloc_exact(unsigned long addr, unsigned int order,
4931 unsigned long alloc_end = addr + (PAGE_SIZE << order);
4932 unsigned long used = addr + PAGE_ALIGN(size);
4934 split_page(virt_to_page((void *)addr), order);
4935 while (used < alloc_end) {
4940 return (void *)addr;
4944 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
4945 * @size: the number of bytes to allocate
4946 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
4948 * This function is similar to alloc_pages(), except that it allocates the
4949 * minimum number of pages to satisfy the request. alloc_pages() can only
4950 * allocate memory in power-of-two pages.
4952 * This function is also limited by MAX_ORDER.
4954 * Memory allocated by this function must be released by free_pages_exact().
4956 * Return: pointer to the allocated area or %NULL in case of error.
4958 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
4960 unsigned int order = get_order(size);
4963 if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
4964 gfp_mask &= ~__GFP_COMP;
4966 addr = __get_free_pages(gfp_mask, order);
4967 return make_alloc_exact(addr, order, size);
4969 EXPORT_SYMBOL(alloc_pages_exact);
4972 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
4974 * @nid: the preferred node ID where memory should be allocated
4975 * @size: the number of bytes to allocate
4976 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
4978 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
4981 * Return: pointer to the allocated area or %NULL in case of error.
4983 void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
4985 unsigned int order = get_order(size);
4988 if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
4989 gfp_mask &= ~__GFP_COMP;
4991 p = alloc_pages_node(nid, gfp_mask, order);
4994 return make_alloc_exact((unsigned long)page_address(p), order, size);
4998 * free_pages_exact - release memory allocated via alloc_pages_exact()
4999 * @virt: the value returned by alloc_pages_exact.
5000 * @size: size of allocation, same value as passed to alloc_pages_exact().
5002 * Release the memory allocated by a previous call to alloc_pages_exact.
5004 void free_pages_exact(void *virt, size_t size)
5006 unsigned long addr = (unsigned long)virt;
5007 unsigned long end = addr + PAGE_ALIGN(size);
5009 while (addr < end) {
5014 EXPORT_SYMBOL(free_pages_exact);
5017 * nr_free_zone_pages - count number of pages beyond high watermark
5018 * @offset: The zone index of the highest zone
5020 * nr_free_zone_pages() counts the number of pages which are beyond the
5021 * high watermark within all zones at or below a given zone index. For each
5022 * zone, the number of pages is calculated as:
5024 * nr_free_zone_pages = managed_pages - high_pages
5026 * Return: number of pages beyond high watermark.
5028 static unsigned long nr_free_zone_pages(int offset)
5033 /* Just pick one node, since fallback list is circular */
5034 unsigned long sum = 0;
5036 struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
5038 for_each_zone_zonelist(zone, z, zonelist, offset) {
5039 unsigned long size = zone_managed_pages(zone);
5040 unsigned long high = high_wmark_pages(zone);
5049 * nr_free_buffer_pages - count number of pages beyond high watermark
5051 * nr_free_buffer_pages() counts the number of pages which are beyond the high
5052 * watermark within ZONE_DMA and ZONE_NORMAL.
5054 * Return: number of pages beyond high watermark within ZONE_DMA and
5057 unsigned long nr_free_buffer_pages(void)
5059 return nr_free_zone_pages(gfp_zone(GFP_USER));
5061 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
5064 * nr_free_pagecache_pages - count number of pages beyond high watermark
5066 * nr_free_pagecache_pages() counts the number of pages which are beyond the
5067 * high watermark within all zones.
5069 * Return: number of pages beyond high watermark within all zones.
5071 unsigned long nr_free_pagecache_pages(void)
5073 return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
5076 static inline void show_node(struct zone *zone)
5078 if (IS_ENABLED(CONFIG_NUMA))
5079 printk("Node %d ", zone_to_nid(zone));
5082 long si_mem_available(void)
5085 unsigned long pagecache;
5086 unsigned long wmark_low = 0;
5087 unsigned long pages[NR_LRU_LISTS];
5088 unsigned long reclaimable;
5092 for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
5093 pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
5096 wmark_low += low_wmark_pages(zone);
5099 * Estimate the amount of memory available for userspace allocations,
5100 * without causing swapping.
5102 available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages;
5105 * Not all the page cache can be freed, otherwise the system will
5106 * start swapping. Assume at least half of the page cache, or the
5107 * low watermark worth of cache, needs to stay.
5109 pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
5110 pagecache -= min(pagecache / 2, wmark_low);
5111 available += pagecache;
5114 * Part of the reclaimable slab and other kernel memory consists of
5115 * items that are in use, and cannot be freed. Cap this estimate at the
5118 reclaimable = global_node_page_state(NR_SLAB_RECLAIMABLE) +
5119 global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
5120 available += reclaimable - min(reclaimable / 2, wmark_low);
5126 EXPORT_SYMBOL_GPL(si_mem_available);
5128 void si_meminfo(struct sysinfo *val)
5130 val->totalram = totalram_pages();
5131 val->sharedram = global_node_page_state(NR_SHMEM);
5132 val->freeram = global_zone_page_state(NR_FREE_PAGES);
5133 val->bufferram = nr_blockdev_pages();
5134 val->totalhigh = totalhigh_pages();
5135 val->freehigh = nr_free_highpages();
5136 val->mem_unit = PAGE_SIZE;
5139 EXPORT_SYMBOL(si_meminfo);
5142 void si_meminfo_node(struct sysinfo *val, int nid)
5144 int zone_type; /* needs to be signed */
5145 unsigned long managed_pages = 0;
5146 unsigned long managed_highpages = 0;
5147 unsigned long free_highpages = 0;
5148 pg_data_t *pgdat = NODE_DATA(nid);
5150 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
5151 managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]);
5152 val->totalram = managed_pages;
5153 val->sharedram = node_page_state(pgdat, NR_SHMEM);
5154 val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
5155 #ifdef CONFIG_HIGHMEM
5156 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
5157 struct zone *zone = &pgdat->node_zones[zone_type];
5159 if (is_highmem(zone)) {
5160 managed_highpages += zone_managed_pages(zone);
5161 free_highpages += zone_page_state(zone, NR_FREE_PAGES);
5164 val->totalhigh = managed_highpages;
5165 val->freehigh = free_highpages;
5167 val->totalhigh = managed_highpages;
5168 val->freehigh = free_highpages;
5170 val->mem_unit = PAGE_SIZE;
5175 * Determine whether the node should be displayed or not, depending on whether
5176 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
5178 static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask)
5180 if (!(flags & SHOW_MEM_FILTER_NODES))
5184 * no node mask - aka implicit memory numa policy. Do not bother with
5185 * the synchronization - read_mems_allowed_begin - because we do not
5186 * have to be precise here.
5189 nodemask = &cpuset_current_mems_allowed;
5191 return !node_isset(nid, *nodemask);
5194 #define K(x) ((x) << (PAGE_SHIFT-10))
5196 static void show_migration_types(unsigned char type)
5198 static const char types[MIGRATE_TYPES] = {
5199 [MIGRATE_UNMOVABLE] = 'U',
5200 [MIGRATE_MOVABLE] = 'M',
5201 [MIGRATE_RECLAIMABLE] = 'E',
5202 [MIGRATE_HIGHATOMIC] = 'H',
5204 [MIGRATE_CMA] = 'C',
5206 #ifdef CONFIG_MEMORY_ISOLATION
5207 [MIGRATE_ISOLATE] = 'I',
5210 char tmp[MIGRATE_TYPES + 1];
5214 for (i = 0; i < MIGRATE_TYPES; i++) {
5215 if (type & (1 << i))
5220 printk(KERN_CONT "(%s) ", tmp);
5224 * Show free area list (used inside shift_scroll-lock stuff)
5225 * We also calculate the percentage fragmentation. We do this by counting the
5226 * memory on each free list with the exception of the first item on the list.
5229 * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
5232 void show_free_areas(unsigned int filter, nodemask_t *nodemask)
5234 unsigned long free_pcp = 0;
5239 for_each_populated_zone(zone) {
5240 if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5243 for_each_online_cpu(cpu)
5244 free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
5247 printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
5248 " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
5249 " unevictable:%lu dirty:%lu writeback:%lu unstable:%lu\n"
5250 " slab_reclaimable:%lu slab_unreclaimable:%lu\n"
5251 " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
5252 " free:%lu free_pcp:%lu free_cma:%lu\n",
5253 global_node_page_state(NR_ACTIVE_ANON),
5254 global_node_page_state(NR_INACTIVE_ANON),
5255 global_node_page_state(NR_ISOLATED_ANON),
5256 global_node_page_state(NR_ACTIVE_FILE),
5257 global_node_page_state(NR_INACTIVE_FILE),
5258 global_node_page_state(NR_ISOLATED_FILE),
5259 global_node_page_state(NR_UNEVICTABLE),
5260 global_node_page_state(NR_FILE_DIRTY),
5261 global_node_page_state(NR_WRITEBACK),
5262 global_node_page_state(NR_UNSTABLE_NFS),
5263 global_node_page_state(NR_SLAB_RECLAIMABLE),
5264 global_node_page_state(NR_SLAB_UNRECLAIMABLE),
5265 global_node_page_state(NR_FILE_MAPPED),
5266 global_node_page_state(NR_SHMEM),
5267 global_zone_page_state(NR_PAGETABLE),
5268 global_zone_page_state(NR_BOUNCE),
5269 global_zone_page_state(NR_FREE_PAGES),
5271 global_zone_page_state(NR_FREE_CMA_PAGES));
5273 for_each_online_pgdat(pgdat) {
5274 if (show_mem_node_skip(filter, pgdat->node_id, nodemask))
5278 " active_anon:%lukB"
5279 " inactive_anon:%lukB"
5280 " active_file:%lukB"
5281 " inactive_file:%lukB"
5282 " unevictable:%lukB"
5283 " isolated(anon):%lukB"
5284 " isolated(file):%lukB"
5289 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5291 " shmem_pmdmapped: %lukB"
5294 " writeback_tmp:%lukB"
5296 " all_unreclaimable? %s"
5299 K(node_page_state(pgdat, NR_ACTIVE_ANON)),
5300 K(node_page_state(pgdat, NR_INACTIVE_ANON)),
5301 K(node_page_state(pgdat, NR_ACTIVE_FILE)),
5302 K(node_page_state(pgdat, NR_INACTIVE_FILE)),
5303 K(node_page_state(pgdat, NR_UNEVICTABLE)),
5304 K(node_page_state(pgdat, NR_ISOLATED_ANON)),
5305 K(node_page_state(pgdat, NR_ISOLATED_FILE)),
5306 K(node_page_state(pgdat, NR_FILE_MAPPED)),
5307 K(node_page_state(pgdat, NR_FILE_DIRTY)),
5308 K(node_page_state(pgdat, NR_WRITEBACK)),
5309 K(node_page_state(pgdat, NR_SHMEM)),
5310 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5311 K(node_page_state(pgdat, NR_SHMEM_THPS) * HPAGE_PMD_NR),
5312 K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)
5314 K(node_page_state(pgdat, NR_ANON_THPS) * HPAGE_PMD_NR),
5316 K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
5317 K(node_page_state(pgdat, NR_UNSTABLE_NFS)),
5318 pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ?
5322 for_each_populated_zone(zone) {
5325 if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5329 for_each_online_cpu(cpu)
5330 free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
5339 " reserved_highatomic:%luKB"
5340 " active_anon:%lukB"
5341 " inactive_anon:%lukB"
5342 " active_file:%lukB"
5343 " inactive_file:%lukB"
5344 " unevictable:%lukB"
5345 " writepending:%lukB"
5349 " kernel_stack:%lukB"
5357 K(zone_page_state(zone, NR_FREE_PAGES)),
5358 K(min_wmark_pages(zone)),
5359 K(low_wmark_pages(zone)),
5360 K(high_wmark_pages(zone)),
5361 K(zone->nr_reserved_highatomic),
5362 K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)),
5363 K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)),
5364 K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
5365 K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
5366 K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
5367 K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
5368 K(zone->present_pages),
5369 K(zone_managed_pages(zone)),
5370 K(zone_page_state(zone, NR_MLOCK)),
5371 zone_page_state(zone, NR_KERNEL_STACK_KB),
5372 K(zone_page_state(zone, NR_PAGETABLE)),
5373 K(zone_page_state(zone, NR_BOUNCE)),
5375 K(this_cpu_read(zone->pageset->pcp.count)),
5376 K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
5377 printk("lowmem_reserve[]:");
5378 for (i = 0; i < MAX_NR_ZONES; i++)
5379 printk(KERN_CONT " %ld", zone->lowmem_reserve[i]);
5380 printk(KERN_CONT "\n");
5383 for_each_populated_zone(zone) {
5385 unsigned long nr[MAX_ORDER], flags, total = 0;
5386 unsigned char types[MAX_ORDER];
5388 if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5391 printk(KERN_CONT "%s: ", zone->name);
5393 spin_lock_irqsave(&zone->lock, flags);
5394 for (order = 0; order < MAX_ORDER; order++) {
5395 struct free_area *area = &zone->free_area[order];
5398 nr[order] = area->nr_free;
5399 total += nr[order] << order;
5402 for (type = 0; type < MIGRATE_TYPES; type++) {
5403 if (!free_area_empty(area, type))
5404 types[order] |= 1 << type;
5407 spin_unlock_irqrestore(&zone->lock, flags);
5408 for (order = 0; order < MAX_ORDER; order++) {
5409 printk(KERN_CONT "%lu*%lukB ",
5410 nr[order], K(1UL) << order);
5412 show_migration_types(types[order]);
5414 printk(KERN_CONT "= %lukB\n", K(total));
5417 hugetlb_show_meminfo();
5419 printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
5421 show_swap_cache_info();
5424 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
5426 zoneref->zone = zone;
5427 zoneref->zone_idx = zone_idx(zone);
5431 * Builds allocation fallback zone lists.
5433 * Add all populated zones of a node to the zonelist.
5435 static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs)
5438 enum zone_type zone_type = MAX_NR_ZONES;
5443 zone = pgdat->node_zones + zone_type;
5444 if (managed_zone(zone)) {
5445 zoneref_set_zone(zone, &zonerefs[nr_zones++]);
5446 check_highest_zone(zone_type);
5448 } while (zone_type);
5455 static int __parse_numa_zonelist_order(char *s)
5458 * We used to support different zonlists modes but they turned
5459 * out to be just not useful. Let's keep the warning in place
5460 * if somebody still use the cmd line parameter so that we do
5461 * not fail it silently
5463 if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) {
5464 pr_warn("Ignoring unsupported numa_zonelist_order value: %s\n", s);
5470 static __init int setup_numa_zonelist_order(char *s)
5475 return __parse_numa_zonelist_order(s);
5477 early_param("numa_zonelist_order", setup_numa_zonelist_order);
5479 char numa_zonelist_order[] = "Node";
5482 * sysctl handler for numa_zonelist_order
5484 int numa_zonelist_order_handler(struct ctl_table *table, int write,
5485 void __user *buffer, size_t *length,
5492 return proc_dostring(table, write, buffer, length, ppos);
5493 str = memdup_user_nul(buffer, 16);
5495 return PTR_ERR(str);
5497 ret = __parse_numa_zonelist_order(str);
5503 #define MAX_NODE_LOAD (nr_online_nodes)
5504 static int node_load[MAX_NUMNODES];
5507 * find_next_best_node - find the next node that should appear in a given node's fallback list
5508 * @node: node whose fallback list we're appending
5509 * @used_node_mask: nodemask_t of already used nodes
5511 * We use a number of factors to determine which is the next node that should
5512 * appear on a given node's fallback list. The node should not have appeared
5513 * already in @node's fallback list, and it should be the next closest node
5514 * according to the distance array (which contains arbitrary distance values
5515 * from each node to each node in the system), and should also prefer nodes
5516 * with no CPUs, since presumably they'll have very little allocation pressure
5517 * on them otherwise.
5519 * Return: node id of the found node or %NUMA_NO_NODE if no node is found.
5521 static int find_next_best_node(int node, nodemask_t *used_node_mask)
5524 int min_val = INT_MAX;
5525 int best_node = NUMA_NO_NODE;
5526 const struct cpumask *tmp = cpumask_of_node(0);
5528 /* Use the local node if we haven't already */
5529 if (!node_isset(node, *used_node_mask)) {
5530 node_set(node, *used_node_mask);
5534 for_each_node_state(n, N_MEMORY) {
5536 /* Don't want a node to appear more than once */
5537 if (node_isset(n, *used_node_mask))
5540 /* Use the distance array to find the distance */
5541 val = node_distance(node, n);
5543 /* Penalize nodes under us ("prefer the next node") */
5546 /* Give preference to headless and unused nodes */
5547 tmp = cpumask_of_node(n);
5548 if (!cpumask_empty(tmp))
5549 val += PENALTY_FOR_NODE_WITH_CPUS;
5551 /* Slight preference for less loaded node */
5552 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
5553 val += node_load[n];
5555 if (val < min_val) {
5562 node_set(best_node, *used_node_mask);
5569 * Build zonelists ordered by node and zones within node.
5570 * This results in maximum locality--normal zone overflows into local
5571 * DMA zone, if any--but risks exhausting DMA zone.
5573 static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order,
5576 struct zoneref *zonerefs;
5579 zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
5581 for (i = 0; i < nr_nodes; i++) {
5584 pg_data_t *node = NODE_DATA(node_order[i]);
5586 nr_zones = build_zonerefs_node(node, zonerefs);
5587 zonerefs += nr_zones;
5589 zonerefs->zone = NULL;
5590 zonerefs->zone_idx = 0;
5594 * Build gfp_thisnode zonelists
5596 static void build_thisnode_zonelists(pg_data_t *pgdat)
5598 struct zoneref *zonerefs;
5601 zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs;
5602 nr_zones = build_zonerefs_node(pgdat, zonerefs);
5603 zonerefs += nr_zones;
5604 zonerefs->zone = NULL;
5605 zonerefs->zone_idx = 0;
5609 * Build zonelists ordered by zone and nodes within zones.
5610 * This results in conserving DMA zone[s] until all Normal memory is
5611 * exhausted, but results in overflowing to remote node while memory
5612 * may still exist in local DMA zone.
5615 static void build_zonelists(pg_data_t *pgdat)
5617 static int node_order[MAX_NUMNODES];
5618 int node, load, nr_nodes = 0;
5619 nodemask_t used_mask;
5620 int local_node, prev_node;
5622 /* NUMA-aware ordering of nodes */
5623 local_node = pgdat->node_id;
5624 load = nr_online_nodes;
5625 prev_node = local_node;
5626 nodes_clear(used_mask);
5628 memset(node_order, 0, sizeof(node_order));
5629 while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
5631 * We don't want to pressure a particular node.
5632 * So adding penalty to the first node in same
5633 * distance group to make it round-robin.
5635 if (node_distance(local_node, node) !=
5636 node_distance(local_node, prev_node))
5637 node_load[node] = load;
5639 node_order[nr_nodes++] = node;
5644 build_zonelists_in_node_order(pgdat, node_order, nr_nodes);
5645 build_thisnode_zonelists(pgdat);
5648 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
5650 * Return node id of node used for "local" allocations.
5651 * I.e., first node id of first zone in arg node's generic zonelist.
5652 * Used for initializing percpu 'numa_mem', which is used primarily
5653 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
5655 int local_memory_node(int node)
5659 z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
5660 gfp_zone(GFP_KERNEL),
5662 return zone_to_nid(z->zone);
5666 static void setup_min_unmapped_ratio(void);
5667 static void setup_min_slab_ratio(void);
5668 #else /* CONFIG_NUMA */
5670 static void build_zonelists(pg_data_t *pgdat)
5672 int node, local_node;
5673 struct zoneref *zonerefs;
5676 local_node = pgdat->node_id;
5678 zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
5679 nr_zones = build_zonerefs_node(pgdat, zonerefs);
5680 zonerefs += nr_zones;
5683 * Now we build the zonelist so that it contains the zones
5684 * of all the other nodes.
5685 * We don't want to pressure a particular node, so when
5686 * building the zones for node N, we make sure that the
5687 * zones coming right after the local ones are those from
5688 * node N+1 (modulo N)
5690 for (node = local_node + 1; node < MAX_NUMNODES; node++) {
5691 if (!node_online(node))
5693 nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
5694 zonerefs += nr_zones;
5696 for (node = 0; node < local_node; node++) {
5697 if (!node_online(node))
5699 nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
5700 zonerefs += nr_zones;
5703 zonerefs->zone = NULL;
5704 zonerefs->zone_idx = 0;
5707 #endif /* CONFIG_NUMA */
5710 * Boot pageset table. One per cpu which is going to be used for all
5711 * zones and all nodes. The parameters will be set in such a way
5712 * that an item put on a list will immediately be handed over to
5713 * the buddy list. This is safe since pageset manipulation is done
5714 * with interrupts disabled.
5716 * The boot_pagesets must be kept even after bootup is complete for
5717 * unused processors and/or zones. They do play a role for bootstrapping
5718 * hotplugged processors.
5720 * zoneinfo_show() and maybe other functions do
5721 * not check if the processor is online before following the pageset pointer.
5722 * Other parts of the kernel may not check if the zone is available.
5724 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
5725 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
5726 static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
5728 static void __build_all_zonelists(void *data)
5731 int __maybe_unused cpu;
5732 pg_data_t *self = data;
5733 static DEFINE_SPINLOCK(lock);
5738 memset(node_load, 0, sizeof(node_load));
5742 * This node is hotadded and no memory is yet present. So just
5743 * building zonelists is fine - no need to touch other nodes.
5745 if (self && !node_online(self->node_id)) {
5746 build_zonelists(self);
5748 for_each_online_node(nid) {
5749 pg_data_t *pgdat = NODE_DATA(nid);
5751 build_zonelists(pgdat);
5754 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
5756 * We now know the "local memory node" for each node--
5757 * i.e., the node of the first zone in the generic zonelist.
5758 * Set up numa_mem percpu variable for on-line cpus. During
5759 * boot, only the boot cpu should be on-line; we'll init the
5760 * secondary cpus' numa_mem as they come on-line. During
5761 * node/memory hotplug, we'll fixup all on-line cpus.
5763 for_each_online_cpu(cpu)
5764 set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
5771 static noinline void __init
5772 build_all_zonelists_init(void)
5776 __build_all_zonelists(NULL);
5779 * Initialize the boot_pagesets that are going to be used
5780 * for bootstrapping processors. The real pagesets for
5781 * each zone will be allocated later when the per cpu
5782 * allocator is available.
5784 * boot_pagesets are used also for bootstrapping offline
5785 * cpus if the system is already booted because the pagesets
5786 * are needed to initialize allocators on a specific cpu too.
5787 * F.e. the percpu allocator needs the page allocator which
5788 * needs the percpu allocator in order to allocate its pagesets
5789 * (a chicken-egg dilemma).
5791 for_each_possible_cpu(cpu)
5792 setup_pageset(&per_cpu(boot_pageset, cpu), 0);
5794 mminit_verify_zonelist();
5795 cpuset_init_current_mems_allowed();
5799 * unless system_state == SYSTEM_BOOTING.
5801 * __ref due to call of __init annotated helper build_all_zonelists_init
5802 * [protected by SYSTEM_BOOTING].
5804 void __ref build_all_zonelists(pg_data_t *pgdat)
5806 if (system_state == SYSTEM_BOOTING) {
5807 build_all_zonelists_init();
5809 __build_all_zonelists(pgdat);
5810 /* cpuset refresh routine should be here */
5812 vm_total_pages = nr_free_pagecache_pages();
5814 * Disable grouping by mobility if the number of pages in the
5815 * system is too low to allow the mechanism to work. It would be
5816 * more accurate, but expensive to check per-zone. This check is
5817 * made on memory-hotadd so a system can start with mobility
5818 * disabled and enable it later
5820 if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
5821 page_group_by_mobility_disabled = 1;
5823 page_group_by_mobility_disabled = 0;
5825 pr_info("Built %u zonelists, mobility grouping %s. Total pages: %ld\n",
5827 page_group_by_mobility_disabled ? "off" : "on",
5830 pr_info("Policy zone: %s\n", zone_names[policy_zone]);
5834 /* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
5835 static bool __meminit
5836 overlap_memmap_init(unsigned long zone, unsigned long *pfn)
5838 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5839 static struct memblock_region *r;
5841 if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
5842 if (!r || *pfn >= memblock_region_memory_end_pfn(r)) {
5843 for_each_memblock(memory, r) {
5844 if (*pfn < memblock_region_memory_end_pfn(r))
5848 if (*pfn >= memblock_region_memory_base_pfn(r) &&
5849 memblock_is_mirror(r)) {
5850 *pfn = memblock_region_memory_end_pfn(r);
5858 #ifdef CONFIG_SPARSEMEM
5859 /* Skip PFNs that belong to non-present sections */
5860 static inline __meminit unsigned long next_pfn(unsigned long pfn)
5862 const unsigned long section_nr = pfn_to_section_nr(++pfn);
5864 if (present_section_nr(section_nr))
5866 return section_nr_to_pfn(next_present_section_nr(section_nr));
5869 static inline __meminit unsigned long next_pfn(unsigned long pfn)
5876 * Initially all pages are reserved - free ones are freed
5877 * up by memblock_free_all() once the early boot process is
5878 * done. Non-atomic initialization, single-pass.
5880 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
5881 unsigned long start_pfn, enum memmap_context context,
5882 struct vmem_altmap *altmap)
5884 unsigned long pfn, end_pfn = start_pfn + size;
5887 if (highest_memmap_pfn < end_pfn - 1)
5888 highest_memmap_pfn = end_pfn - 1;
5890 #ifdef CONFIG_ZONE_DEVICE
5892 * Honor reservation requested by the driver for this ZONE_DEVICE
5893 * memory. We limit the total number of pages to initialize to just
5894 * those that might contain the memory mapping. We will defer the
5895 * ZONE_DEVICE page initialization until after we have released
5898 if (zone == ZONE_DEVICE) {
5902 if (start_pfn == altmap->base_pfn)
5903 start_pfn += altmap->reserve;
5904 end_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
5908 for (pfn = start_pfn; pfn < end_pfn; ) {
5910 * There can be holes in boot-time mem_map[]s handed to this
5911 * function. They do not exist on hotplugged memory.
5913 if (context == MEMMAP_EARLY) {
5914 if (!early_pfn_valid(pfn)) {
5915 pfn = next_pfn(pfn);
5918 if (!early_pfn_in_nid(pfn, nid)) {
5922 if (overlap_memmap_init(zone, &pfn))
5924 if (defer_init(nid, pfn, end_pfn))
5928 page = pfn_to_page(pfn);
5929 __init_single_page(page, pfn, zone, nid);
5930 if (context == MEMMAP_HOTPLUG)
5931 __SetPageReserved(page);
5934 * Mark the block movable so that blocks are reserved for
5935 * movable at startup. This will force kernel allocations
5936 * to reserve their blocks rather than leaking throughout
5937 * the address space during boot when many long-lived
5938 * kernel allocations are made.
5940 * bitmap is created for zone's valid pfn range. but memmap
5941 * can be created for invalid pages (for alignment)
5942 * check here not to call set_pageblock_migratetype() against
5945 if (!(pfn & (pageblock_nr_pages - 1))) {
5946 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5953 #ifdef CONFIG_ZONE_DEVICE
5954 void __ref memmap_init_zone_device(struct zone *zone,
5955 unsigned long start_pfn,
5956 unsigned long nr_pages,
5957 struct dev_pagemap *pgmap)
5959 unsigned long pfn, end_pfn = start_pfn + nr_pages;
5960 struct pglist_data *pgdat = zone->zone_pgdat;
5961 struct vmem_altmap *altmap = pgmap_altmap(pgmap);
5962 unsigned long zone_idx = zone_idx(zone);
5963 unsigned long start = jiffies;
5964 int nid = pgdat->node_id;
5966 if (WARN_ON_ONCE(!pgmap || zone_idx(zone) != ZONE_DEVICE))
5970 * The call to memmap_init_zone should have already taken care
5971 * of the pages reserved for the memmap, so we can just jump to
5972 * the end of that region and start processing the device pages.
5975 start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
5976 nr_pages = end_pfn - start_pfn;
5979 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
5980 struct page *page = pfn_to_page(pfn);
5982 __init_single_page(page, pfn, zone_idx, nid);
5985 * Mark page reserved as it will need to wait for onlining
5986 * phase for it to be fully associated with a zone.
5988 * We can use the non-atomic __set_bit operation for setting
5989 * the flag as we are still initializing the pages.
5991 __SetPageReserved(page);
5994 * ZONE_DEVICE pages union ->lru with a ->pgmap back pointer
5995 * and zone_device_data. It is a bug if a ZONE_DEVICE page is
5996 * ever freed or placed on a driver-private list.
5998 page->pgmap = pgmap;
5999 page->zone_device_data = NULL;
6002 * Mark the block movable so that blocks are reserved for
6003 * movable at startup. This will force kernel allocations
6004 * to reserve their blocks rather than leaking throughout
6005 * the address space during boot when many long-lived
6006 * kernel allocations are made.
6008 * bitmap is created for zone's valid pfn range. but memmap
6009 * can be created for invalid pages (for alignment)
6010 * check here not to call set_pageblock_migratetype() against
6013 * Please note that MEMMAP_HOTPLUG path doesn't clear memmap
6014 * because this is done early in section_activate()
6016 if (!(pfn & (pageblock_nr_pages - 1))) {
6017 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
6022 pr_info("%s initialised %lu pages in %ums\n", __func__,
6023 nr_pages, jiffies_to_msecs(jiffies - start));
6027 static void __meminit zone_init_free_lists(struct zone *zone)
6029 unsigned int order, t;
6030 for_each_migratetype_order(order, t) {
6031 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
6032 zone->free_area[order].nr_free = 0;
6036 void __meminit __weak memmap_init(unsigned long size, int nid,
6037 unsigned long zone, unsigned long start_pfn)
6039 memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL);
6042 static int zone_batchsize(struct zone *zone)
6048 * The per-cpu-pages pools are set to around 1000th of the
6051 batch = zone_managed_pages(zone) / 1024;
6052 /* But no more than a meg. */
6053 if (batch * PAGE_SIZE > 1024 * 1024)
6054 batch = (1024 * 1024) / PAGE_SIZE;
6055 batch /= 4; /* We effectively *= 4 below */
6060 * Clamp the batch to a 2^n - 1 value. Having a power
6061 * of 2 value was found to be more likely to have
6062 * suboptimal cache aliasing properties in some cases.
6064 * For example if 2 tasks are alternately allocating
6065 * batches of pages, one task can end up with a lot
6066 * of pages of one half of the possible page colors
6067 * and the other with pages of the other colors.
6069 batch = rounddown_pow_of_two(batch + batch/2) - 1;
6074 /* The deferral and batching of frees should be suppressed under NOMMU
6077 * The problem is that NOMMU needs to be able to allocate large chunks
6078 * of contiguous memory as there's no hardware page translation to
6079 * assemble apparent contiguous memory from discontiguous pages.
6081 * Queueing large contiguous runs of pages for batching, however,
6082 * causes the pages to actually be freed in smaller chunks. As there
6083 * can be a significant delay between the individual batches being
6084 * recycled, this leads to the once large chunks of space being
6085 * fragmented and becoming unavailable for high-order allocations.
6092 * pcp->high and pcp->batch values are related and dependent on one another:
6093 * ->batch must never be higher then ->high.
6094 * The following function updates them in a safe manner without read side
6097 * Any new users of pcp->batch and pcp->high should ensure they can cope with
6098 * those fields changing asynchronously (acording the the above rule).
6100 * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
6101 * outside of boot time (or some other assurance that no concurrent updaters
6104 static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
6105 unsigned long batch)
6107 /* start with a fail safe value for batch */
6111 /* Update high, then batch, in order */
6118 /* a companion to pageset_set_high() */
6119 static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
6121 pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
6124 static void pageset_init(struct per_cpu_pageset *p)
6126 struct per_cpu_pages *pcp;
6129 memset(p, 0, sizeof(*p));
6132 for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
6133 INIT_LIST_HEAD(&pcp->lists[migratetype]);
6136 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
6139 pageset_set_batch(p, batch);
6143 * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
6144 * to the value high for the pageset p.
6146 static void pageset_set_high(struct per_cpu_pageset *p,
6149 unsigned long batch = max(1UL, high / 4);
6150 if ((high / 4) > (PAGE_SHIFT * 8))
6151 batch = PAGE_SHIFT * 8;
6153 pageset_update(&p->pcp, high, batch);
6156 static void pageset_set_high_and_batch(struct zone *zone,
6157 struct per_cpu_pageset *pcp)
6159 if (percpu_pagelist_fraction)
6160 pageset_set_high(pcp,
6161 (zone_managed_pages(zone) /
6162 percpu_pagelist_fraction));
6164 pageset_set_batch(pcp, zone_batchsize(zone));
6167 static void __meminit zone_pageset_init(struct zone *zone, int cpu)
6169 struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
6172 pageset_set_high_and_batch(zone, pcp);
6175 void __meminit setup_zone_pageset(struct zone *zone)
6178 zone->pageset = alloc_percpu(struct per_cpu_pageset);
6179 for_each_possible_cpu(cpu)
6180 zone_pageset_init(zone, cpu);
6184 * Allocate per cpu pagesets and initialize them.
6185 * Before this call only boot pagesets were available.
6187 void __init setup_per_cpu_pageset(void)
6189 struct pglist_data *pgdat;
6192 for_each_populated_zone(zone)
6193 setup_zone_pageset(zone);
6195 for_each_online_pgdat(pgdat)
6196 pgdat->per_cpu_nodestats =
6197 alloc_percpu(struct per_cpu_nodestat);
6200 static __meminit void zone_pcp_init(struct zone *zone)
6203 * per cpu subsystem is not up at this point. The following code
6204 * relies on the ability of the linker to provide the
6205 * offset of a (static) per cpu variable into the per cpu area.
6207 zone->pageset = &boot_pageset;
6209 if (populated_zone(zone))
6210 printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n",
6211 zone->name, zone->present_pages,
6212 zone_batchsize(zone));
6215 void __meminit init_currently_empty_zone(struct zone *zone,
6216 unsigned long zone_start_pfn,
6219 struct pglist_data *pgdat = zone->zone_pgdat;
6220 int zone_idx = zone_idx(zone) + 1;
6222 if (zone_idx > pgdat->nr_zones)
6223 pgdat->nr_zones = zone_idx;
6225 zone->zone_start_pfn = zone_start_pfn;
6227 mminit_dprintk(MMINIT_TRACE, "memmap_init",
6228 "Initialising map node %d zone %lu pfns %lu -> %lu\n",
6230 (unsigned long)zone_idx(zone),
6231 zone_start_pfn, (zone_start_pfn + size));
6233 zone_init_free_lists(zone);
6234 zone->initialized = 1;
6237 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
6238 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
6241 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
6243 int __meminit __early_pfn_to_nid(unsigned long pfn,
6244 struct mminit_pfnnid_cache *state)
6246 unsigned long start_pfn, end_pfn;
6249 if (state->last_start <= pfn && pfn < state->last_end)
6250 return state->last_nid;
6252 nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
6253 if (nid != NUMA_NO_NODE) {
6254 state->last_start = start_pfn;
6255 state->last_end = end_pfn;
6256 state->last_nid = nid;
6261 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
6264 * free_bootmem_with_active_regions - Call memblock_free_early_nid for each active range
6265 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
6266 * @max_low_pfn: The highest PFN that will be passed to memblock_free_early_nid
6268 * If an architecture guarantees that all ranges registered contain no holes
6269 * and may be freed, this this function may be used instead of calling
6270 * memblock_free_early_nid() manually.
6272 void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
6274 unsigned long start_pfn, end_pfn;
6277 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
6278 start_pfn = min(start_pfn, max_low_pfn);
6279 end_pfn = min(end_pfn, max_low_pfn);
6281 if (start_pfn < end_pfn)
6282 memblock_free_early_nid(PFN_PHYS(start_pfn),
6283 (end_pfn - start_pfn) << PAGE_SHIFT,
6289 * sparse_memory_present_with_active_regions - Call memory_present for each active range
6290 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
6292 * If an architecture guarantees that all ranges registered contain no holes and may
6293 * be freed, this function may be used instead of calling memory_present() manually.
6295 void __init sparse_memory_present_with_active_regions(int nid)
6297 unsigned long start_pfn, end_pfn;
6300 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
6301 memory_present(this_nid, start_pfn, end_pfn);
6305 * get_pfn_range_for_nid - Return the start and end page frames for a node
6306 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
6307 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
6308 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
6310 * It returns the start and end page frame of a node based on information
6311 * provided by memblock_set_node(). If called for a node
6312 * with no available memory, a warning is printed and the start and end
6315 void __init get_pfn_range_for_nid(unsigned int nid,
6316 unsigned long *start_pfn, unsigned long *end_pfn)
6318 unsigned long this_start_pfn, this_end_pfn;
6324 for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
6325 *start_pfn = min(*start_pfn, this_start_pfn);
6326 *end_pfn = max(*end_pfn, this_end_pfn);
6329 if (*start_pfn == -1UL)
6334 * This finds a zone that can be used for ZONE_MOVABLE pages. The
6335 * assumption is made that zones within a node are ordered in monotonic
6336 * increasing memory addresses so that the "highest" populated zone is used
6338 static void __init find_usable_zone_for_movable(void)
6341 for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
6342 if (zone_index == ZONE_MOVABLE)
6345 if (arch_zone_highest_possible_pfn[zone_index] >
6346 arch_zone_lowest_possible_pfn[zone_index])
6350 VM_BUG_ON(zone_index == -1);
6351 movable_zone = zone_index;
6355 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
6356 * because it is sized independent of architecture. Unlike the other zones,
6357 * the starting point for ZONE_MOVABLE is not fixed. It may be different
6358 * in each node depending on the size of each node and how evenly kernelcore
6359 * is distributed. This helper function adjusts the zone ranges
6360 * provided by the architecture for a given node by using the end of the
6361 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
6362 * zones within a node are in order of monotonic increases memory addresses
6364 static void __init adjust_zone_range_for_zone_movable(int nid,
6365 unsigned long zone_type,
6366 unsigned long node_start_pfn,
6367 unsigned long node_end_pfn,
6368 unsigned long *zone_start_pfn,
6369 unsigned long *zone_end_pfn)
6371 /* Only adjust if ZONE_MOVABLE is on this node */
6372 if (zone_movable_pfn[nid]) {
6373 /* Size ZONE_MOVABLE */
6374 if (zone_type == ZONE_MOVABLE) {
6375 *zone_start_pfn = zone_movable_pfn[nid];
6376 *zone_end_pfn = min(node_end_pfn,
6377 arch_zone_highest_possible_pfn[movable_zone]);
6379 /* Adjust for ZONE_MOVABLE starting within this range */
6380 } else if (!mirrored_kernelcore &&
6381 *zone_start_pfn < zone_movable_pfn[nid] &&
6382 *zone_end_pfn > zone_movable_pfn[nid]) {
6383 *zone_end_pfn = zone_movable_pfn[nid];
6385 /* Check if this whole range is within ZONE_MOVABLE */
6386 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
6387 *zone_start_pfn = *zone_end_pfn;
6392 * Return the number of pages a zone spans in a node, including holes
6393 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
6395 static unsigned long __init zone_spanned_pages_in_node(int nid,
6396 unsigned long zone_type,
6397 unsigned long node_start_pfn,
6398 unsigned long node_end_pfn,
6399 unsigned long *zone_start_pfn,
6400 unsigned long *zone_end_pfn,
6401 unsigned long *ignored)
6403 unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
6404 unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
6405 /* When hotadd a new node from cpu_up(), the node should be empty */
6406 if (!node_start_pfn && !node_end_pfn)
6409 /* Get the start and end of the zone */
6410 *zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
6411 *zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
6412 adjust_zone_range_for_zone_movable(nid, zone_type,
6413 node_start_pfn, node_end_pfn,
6414 zone_start_pfn, zone_end_pfn);
6416 /* Check that this node has pages within the zone's required range */
6417 if (*zone_end_pfn < node_start_pfn || *zone_start_pfn > node_end_pfn)
6420 /* Move the zone boundaries inside the node if necessary */
6421 *zone_end_pfn = min(*zone_end_pfn, node_end_pfn);
6422 *zone_start_pfn = max(*zone_start_pfn, node_start_pfn);
6424 /* Return the spanned pages */
6425 return *zone_end_pfn - *zone_start_pfn;
6429 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
6430 * then all holes in the requested range will be accounted for.
6432 unsigned long __init __absent_pages_in_range(int nid,
6433 unsigned long range_start_pfn,
6434 unsigned long range_end_pfn)
6436 unsigned long nr_absent = range_end_pfn - range_start_pfn;
6437 unsigned long start_pfn, end_pfn;
6440 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
6441 start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
6442 end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
6443 nr_absent -= end_pfn - start_pfn;
6449 * absent_pages_in_range - Return number of page frames in holes within a range
6450 * @start_pfn: The start PFN to start searching for holes
6451 * @end_pfn: The end PFN to stop searching for holes
6453 * Return: the number of pages frames in memory holes within a range.
6455 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
6456 unsigned long end_pfn)
6458 return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
6461 /* Return the number of page frames in holes in a zone on a node */
6462 static unsigned long __init zone_absent_pages_in_node(int nid,
6463 unsigned long zone_type,
6464 unsigned long node_start_pfn,
6465 unsigned long node_end_pfn,
6466 unsigned long *ignored)
6468 unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
6469 unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
6470 unsigned long zone_start_pfn, zone_end_pfn;
6471 unsigned long nr_absent;
6473 /* When hotadd a new node from cpu_up(), the node should be empty */
6474 if (!node_start_pfn && !node_end_pfn)
6477 zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
6478 zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
6480 adjust_zone_range_for_zone_movable(nid, zone_type,
6481 node_start_pfn, node_end_pfn,
6482 &zone_start_pfn, &zone_end_pfn);
6483 nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
6486 * ZONE_MOVABLE handling.
6487 * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
6490 if (mirrored_kernelcore && zone_movable_pfn[nid]) {
6491 unsigned long start_pfn, end_pfn;
6492 struct memblock_region *r;
6494 for_each_memblock(memory, r) {
6495 start_pfn = clamp(memblock_region_memory_base_pfn(r),
6496 zone_start_pfn, zone_end_pfn);
6497 end_pfn = clamp(memblock_region_memory_end_pfn(r),
6498 zone_start_pfn, zone_end_pfn);
6500 if (zone_type == ZONE_MOVABLE &&
6501 memblock_is_mirror(r))
6502 nr_absent += end_pfn - start_pfn;
6504 if (zone_type == ZONE_NORMAL &&
6505 !memblock_is_mirror(r))
6506 nr_absent += end_pfn - start_pfn;
6513 #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6514 static inline unsigned long __init zone_spanned_pages_in_node(int nid,
6515 unsigned long zone_type,
6516 unsigned long node_start_pfn,
6517 unsigned long node_end_pfn,
6518 unsigned long *zone_start_pfn,
6519 unsigned long *zone_end_pfn,
6520 unsigned long *zones_size)
6524 *zone_start_pfn = node_start_pfn;
6525 for (zone = 0; zone < zone_type; zone++)
6526 *zone_start_pfn += zones_size[zone];
6528 *zone_end_pfn = *zone_start_pfn + zones_size[zone_type];
6530 return zones_size[zone_type];
6533 static inline unsigned long __init zone_absent_pages_in_node(int nid,
6534 unsigned long zone_type,
6535 unsigned long node_start_pfn,
6536 unsigned long node_end_pfn,
6537 unsigned long *zholes_size)
6542 return zholes_size[zone_type];
6545 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6547 static void __init calculate_node_totalpages(struct pglist_data *pgdat,
6548 unsigned long node_start_pfn,
6549 unsigned long node_end_pfn,
6550 unsigned long *zones_size,
6551 unsigned long *zholes_size)
6553 unsigned long realtotalpages = 0, totalpages = 0;
6556 for (i = 0; i < MAX_NR_ZONES; i++) {
6557 struct zone *zone = pgdat->node_zones + i;
6558 unsigned long zone_start_pfn, zone_end_pfn;
6559 unsigned long size, real_size;
6561 size = zone_spanned_pages_in_node(pgdat->node_id, i,
6567 real_size = size - zone_absent_pages_in_node(pgdat->node_id, i,
6568 node_start_pfn, node_end_pfn,
6571 zone->zone_start_pfn = zone_start_pfn;
6573 zone->zone_start_pfn = 0;
6574 zone->spanned_pages = size;
6575 zone->present_pages = real_size;
6578 realtotalpages += real_size;
6581 pgdat->node_spanned_pages = totalpages;
6582 pgdat->node_present_pages = realtotalpages;
6583 printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
6587 #ifndef CONFIG_SPARSEMEM
6589 * Calculate the size of the zone->blockflags rounded to an unsigned long
6590 * Start by making sure zonesize is a multiple of pageblock_order by rounding
6591 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
6592 * round what is now in bits to nearest long in bits, then return it in
6595 static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
6597 unsigned long usemapsize;
6599 zonesize += zone_start_pfn & (pageblock_nr_pages-1);
6600 usemapsize = roundup(zonesize, pageblock_nr_pages);
6601 usemapsize = usemapsize >> pageblock_order;
6602 usemapsize *= NR_PAGEBLOCK_BITS;
6603 usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
6605 return usemapsize / 8;
6608 static void __ref setup_usemap(struct pglist_data *pgdat,
6610 unsigned long zone_start_pfn,
6611 unsigned long zonesize)
6613 unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
6614 zone->pageblock_flags = NULL;
6616 zone->pageblock_flags =
6617 memblock_alloc_node(usemapsize, SMP_CACHE_BYTES,
6619 if (!zone->pageblock_flags)
6620 panic("Failed to allocate %ld bytes for zone %s pageblock flags on node %d\n",
6621 usemapsize, zone->name, pgdat->node_id);
6625 static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
6626 unsigned long zone_start_pfn, unsigned long zonesize) {}
6627 #endif /* CONFIG_SPARSEMEM */
6629 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
6631 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
6632 void __init set_pageblock_order(void)
6636 /* Check that pageblock_nr_pages has not already been setup */
6637 if (pageblock_order)
6640 if (HPAGE_SHIFT > PAGE_SHIFT)
6641 order = HUGETLB_PAGE_ORDER;
6643 order = MAX_ORDER - 1;
6646 * Assume the largest contiguous order of interest is a huge page.
6647 * This value may be variable depending on boot parameters on IA64 and
6650 pageblock_order = order;
6652 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
6655 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
6656 * is unused as pageblock_order is set at compile-time. See
6657 * include/linux/pageblock-flags.h for the values of pageblock_order based on
6660 void __init set_pageblock_order(void)
6664 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
6666 static unsigned long __init calc_memmap_size(unsigned long spanned_pages,
6667 unsigned long present_pages)
6669 unsigned long pages = spanned_pages;
6672 * Provide a more accurate estimation if there are holes within
6673 * the zone and SPARSEMEM is in use. If there are holes within the
6674 * zone, each populated memory region may cost us one or two extra
6675 * memmap pages due to alignment because memmap pages for each
6676 * populated regions may not be naturally aligned on page boundary.
6677 * So the (present_pages >> 4) heuristic is a tradeoff for that.
6679 if (spanned_pages > present_pages + (present_pages >> 4) &&
6680 IS_ENABLED(CONFIG_SPARSEMEM))
6681 pages = present_pages;
6683 return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
6686 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6687 static void pgdat_init_split_queue(struct pglist_data *pgdat)
6689 struct deferred_split *ds_queue = &pgdat->deferred_split_queue;
6691 spin_lock_init(&ds_queue->split_queue_lock);
6692 INIT_LIST_HEAD(&ds_queue->split_queue);
6693 ds_queue->split_queue_len = 0;
6696 static void pgdat_init_split_queue(struct pglist_data *pgdat) {}
6699 #ifdef CONFIG_COMPACTION
6700 static void pgdat_init_kcompactd(struct pglist_data *pgdat)
6702 init_waitqueue_head(&pgdat->kcompactd_wait);
6705 static void pgdat_init_kcompactd(struct pglist_data *pgdat) {}
6708 static void __meminit pgdat_init_internals(struct pglist_data *pgdat)
6710 pgdat_resize_init(pgdat);
6712 pgdat_init_split_queue(pgdat);
6713 pgdat_init_kcompactd(pgdat);
6715 init_waitqueue_head(&pgdat->kswapd_wait);
6716 init_waitqueue_head(&pgdat->pfmemalloc_wait);
6718 pgdat_page_ext_init(pgdat);
6719 spin_lock_init(&pgdat->lru_lock);
6720 lruvec_init(&pgdat->__lruvec);
6723 static void __meminit zone_init_internals(struct zone *zone, enum zone_type idx, int nid,
6724 unsigned long remaining_pages)
6726 atomic_long_set(&zone->managed_pages, remaining_pages);
6727 zone_set_nid(zone, nid);
6728 zone->name = zone_names[idx];
6729 zone->zone_pgdat = NODE_DATA(nid);
6730 spin_lock_init(&zone->lock);
6731 zone_seqlock_init(zone);
6732 zone_pcp_init(zone);
6736 * Set up the zone data structures
6737 * - init pgdat internals
6738 * - init all zones belonging to this node
6740 * NOTE: this function is only called during memory hotplug
6742 #ifdef CONFIG_MEMORY_HOTPLUG
6743 void __ref free_area_init_core_hotplug(int nid)
6746 pg_data_t *pgdat = NODE_DATA(nid);
6748 pgdat_init_internals(pgdat);
6749 for (z = 0; z < MAX_NR_ZONES; z++)
6750 zone_init_internals(&pgdat->node_zones[z], z, nid, 0);
6755 * Set up the zone data structures:
6756 * - mark all pages reserved
6757 * - mark all memory queues empty
6758 * - clear the memory bitmaps
6760 * NOTE: pgdat should get zeroed by caller.
6761 * NOTE: this function is only called during early init.
6763 static void __init free_area_init_core(struct pglist_data *pgdat)
6766 int nid = pgdat->node_id;
6768 pgdat_init_internals(pgdat);
6769 pgdat->per_cpu_nodestats = &boot_nodestats;
6771 for (j = 0; j < MAX_NR_ZONES; j++) {
6772 struct zone *zone = pgdat->node_zones + j;
6773 unsigned long size, freesize, memmap_pages;
6774 unsigned long zone_start_pfn = zone->zone_start_pfn;
6776 size = zone->spanned_pages;
6777 freesize = zone->present_pages;
6780 * Adjust freesize so that it accounts for how much memory
6781 * is used by this zone for memmap. This affects the watermark
6782 * and per-cpu initialisations
6784 memmap_pages = calc_memmap_size(size, freesize);
6785 if (!is_highmem_idx(j)) {
6786 if (freesize >= memmap_pages) {
6787 freesize -= memmap_pages;
6790 " %s zone: %lu pages used for memmap\n",
6791 zone_names[j], memmap_pages);
6793 pr_warn(" %s zone: %lu pages exceeds freesize %lu\n",
6794 zone_names[j], memmap_pages, freesize);
6797 /* Account for reserved pages */
6798 if (j == 0 && freesize > dma_reserve) {
6799 freesize -= dma_reserve;
6800 printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
6801 zone_names[0], dma_reserve);
6804 if (!is_highmem_idx(j))
6805 nr_kernel_pages += freesize;
6806 /* Charge for highmem memmap if there are enough kernel pages */
6807 else if (nr_kernel_pages > memmap_pages * 2)
6808 nr_kernel_pages -= memmap_pages;
6809 nr_all_pages += freesize;
6812 * Set an approximate value for lowmem here, it will be adjusted
6813 * when the bootmem allocator frees pages into the buddy system.
6814 * And all highmem pages will be managed by the buddy system.
6816 zone_init_internals(zone, j, nid, freesize);
6821 set_pageblock_order();
6822 setup_usemap(pgdat, zone, zone_start_pfn, size);
6823 init_currently_empty_zone(zone, zone_start_pfn, size);
6824 memmap_init(size, nid, j, zone_start_pfn);
6828 #ifdef CONFIG_FLAT_NODE_MEM_MAP
6829 static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
6831 unsigned long __maybe_unused start = 0;
6832 unsigned long __maybe_unused offset = 0;
6834 /* Skip empty nodes */
6835 if (!pgdat->node_spanned_pages)
6838 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
6839 offset = pgdat->node_start_pfn - start;
6840 /* ia64 gets its own node_mem_map, before this, without bootmem */
6841 if (!pgdat->node_mem_map) {
6842 unsigned long size, end;
6846 * The zone's endpoints aren't required to be MAX_ORDER
6847 * aligned but the node_mem_map endpoints must be in order
6848 * for the buddy allocator to function correctly.
6850 end = pgdat_end_pfn(pgdat);
6851 end = ALIGN(end, MAX_ORDER_NR_PAGES);
6852 size = (end - start) * sizeof(struct page);
6853 map = memblock_alloc_node(size, SMP_CACHE_BYTES,
6856 panic("Failed to allocate %ld bytes for node %d memory map\n",
6857 size, pgdat->node_id);
6858 pgdat->node_mem_map = map + offset;
6860 pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
6861 __func__, pgdat->node_id, (unsigned long)pgdat,
6862 (unsigned long)pgdat->node_mem_map);
6863 #ifndef CONFIG_NEED_MULTIPLE_NODES
6865 * With no DISCONTIG, the global mem_map is just set as node 0's
6867 if (pgdat == NODE_DATA(0)) {
6868 mem_map = NODE_DATA(0)->node_mem_map;
6869 #if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM)
6870 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
6872 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6877 static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { }
6878 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
6880 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
6881 static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
6883 pgdat->first_deferred_pfn = ULONG_MAX;
6886 static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
6889 void __init free_area_init_node(int nid, unsigned long *zones_size,
6890 unsigned long node_start_pfn,
6891 unsigned long *zholes_size)
6893 pg_data_t *pgdat = NODE_DATA(nid);
6894 unsigned long start_pfn = 0;
6895 unsigned long end_pfn = 0;
6897 /* pg_data_t should be reset to zero when it's allocated */
6898 WARN_ON(pgdat->nr_zones || pgdat->kswapd_classzone_idx);
6900 pgdat->node_id = nid;
6901 pgdat->node_start_pfn = node_start_pfn;
6902 pgdat->per_cpu_nodestats = NULL;
6903 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
6904 get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
6905 pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
6906 (u64)start_pfn << PAGE_SHIFT,
6907 end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
6909 start_pfn = node_start_pfn;
6911 calculate_node_totalpages(pgdat, start_pfn, end_pfn,
6912 zones_size, zholes_size);
6914 alloc_node_mem_map(pgdat);
6915 pgdat_set_deferred_range(pgdat);
6917 free_area_init_core(pgdat);
6920 #if !defined(CONFIG_FLAT_NODE_MEM_MAP)
6922 * Initialize all valid struct pages in the range [spfn, epfn) and mark them
6923 * PageReserved(). Return the number of struct pages that were initialized.
6925 static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn)
6930 for (pfn = spfn; pfn < epfn; pfn++) {
6931 if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
6932 pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
6933 + pageblock_nr_pages - 1;
6937 * Use a fake node/zone (0) for now. Some of these pages
6938 * (in memblock.reserved but not in memblock.memory) will
6939 * get re-initialized via reserve_bootmem_region() later.
6941 __init_single_page(pfn_to_page(pfn), pfn, 0, 0);
6942 __SetPageReserved(pfn_to_page(pfn));
6950 * Only struct pages that are backed by physical memory are zeroed and
6951 * initialized by going through __init_single_page(). But, there are some
6952 * struct pages which are reserved in memblock allocator and their fields
6953 * may be accessed (for example page_to_pfn() on some configuration accesses
6954 * flags). We must explicitly initialize those struct pages.
6956 * This function also addresses a similar issue where struct pages are left
6957 * uninitialized because the physical address range is not covered by
6958 * memblock.memory or memblock.reserved. That could happen when memblock
6959 * layout is manually configured via memmap=, or when the highest physical
6960 * address (max_pfn) does not end on a section boundary.
6962 static void __init init_unavailable_mem(void)
6964 phys_addr_t start, end;
6966 phys_addr_t next = 0;
6969 * Loop through unavailable ranges not covered by memblock.memory.
6972 for_each_mem_range(i, &memblock.memory, NULL,
6973 NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) {
6975 pgcnt += init_unavailable_range(PFN_DOWN(next),
6981 * Early sections always have a fully populated memmap for the whole
6982 * section - see pfn_valid(). If the last section has holes at the
6983 * end and that section is marked "online", the memmap will be
6984 * considered initialized. Make sure that memmap has a well defined
6987 pgcnt += init_unavailable_range(PFN_DOWN(next),
6988 round_up(max_pfn, PAGES_PER_SECTION));
6991 * Struct pages that do not have backing memory. This could be because
6992 * firmware is using some of this memory, or for some other reasons.
6995 pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt);
6998 static inline void __init init_unavailable_mem(void)
7001 #endif /* !CONFIG_FLAT_NODE_MEM_MAP */
7003 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
7005 #if MAX_NUMNODES > 1
7007 * Figure out the number of possible node ids.
7009 void __init setup_nr_node_ids(void)
7011 unsigned int highest;
7013 highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES);
7014 nr_node_ids = highest + 1;
7019 * node_map_pfn_alignment - determine the maximum internode alignment
7021 * This function should be called after node map is populated and sorted.
7022 * It calculates the maximum power of two alignment which can distinguish
7025 * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
7026 * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)). If the
7027 * nodes are shifted by 256MiB, 256MiB. Note that if only the last node is
7028 * shifted, 1GiB is enough and this function will indicate so.
7030 * This is used to test whether pfn -> nid mapping of the chosen memory
7031 * model has fine enough granularity to avoid incorrect mapping for the
7032 * populated node map.
7034 * Return: the determined alignment in pfn's. 0 if there is no alignment
7035 * requirement (single node).
7037 unsigned long __init node_map_pfn_alignment(void)
7039 unsigned long accl_mask = 0, last_end = 0;
7040 unsigned long start, end, mask;
7041 int last_nid = NUMA_NO_NODE;
7044 for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
7045 if (!start || last_nid < 0 || last_nid == nid) {
7052 * Start with a mask granular enough to pin-point to the
7053 * start pfn and tick off bits one-by-one until it becomes
7054 * too coarse to separate the current node from the last.
7056 mask = ~((1 << __ffs(start)) - 1);
7057 while (mask && last_end <= (start & (mask << 1)))
7060 /* accumulate all internode masks */
7064 /* convert mask to number of pages */
7065 return ~accl_mask + 1;
7068 /* Find the lowest pfn for a node */
7069 static unsigned long __init find_min_pfn_for_node(int nid)
7071 unsigned long min_pfn = ULONG_MAX;
7072 unsigned long start_pfn;
7075 for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
7076 min_pfn = min(min_pfn, start_pfn);
7078 if (min_pfn == ULONG_MAX) {
7079 pr_warn("Could not find start_pfn for node %d\n", nid);
7087 * find_min_pfn_with_active_regions - Find the minimum PFN registered
7089 * Return: the minimum PFN based on information provided via
7090 * memblock_set_node().
7092 unsigned long __init find_min_pfn_with_active_regions(void)
7094 return find_min_pfn_for_node(MAX_NUMNODES);
7098 * early_calculate_totalpages()
7099 * Sum pages in active regions for movable zone.
7100 * Populate N_MEMORY for calculating usable_nodes.
7102 static unsigned long __init early_calculate_totalpages(void)
7104 unsigned long totalpages = 0;
7105 unsigned long start_pfn, end_pfn;
7108 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
7109 unsigned long pages = end_pfn - start_pfn;
7111 totalpages += pages;
7113 node_set_state(nid, N_MEMORY);
7119 * Find the PFN the Movable zone begins in each node. Kernel memory
7120 * is spread evenly between nodes as long as the nodes have enough
7121 * memory. When they don't, some nodes will have more kernelcore than
7124 static void __init find_zone_movable_pfns_for_nodes(void)
7127 unsigned long usable_startpfn;
7128 unsigned long kernelcore_node, kernelcore_remaining;
7129 /* save the state before borrow the nodemask */
7130 nodemask_t saved_node_state = node_states[N_MEMORY];
7131 unsigned long totalpages = early_calculate_totalpages();
7132 int usable_nodes = nodes_weight(node_states[N_MEMORY]);
7133 struct memblock_region *r;
7135 /* Need to find movable_zone earlier when movable_node is specified. */
7136 find_usable_zone_for_movable();
7139 * If movable_node is specified, ignore kernelcore and movablecore
7142 if (movable_node_is_enabled()) {
7143 for_each_memblock(memory, r) {
7144 if (!memblock_is_hotpluggable(r))
7149 usable_startpfn = PFN_DOWN(r->base);
7150 zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
7151 min(usable_startpfn, zone_movable_pfn[nid]) :
7159 * If kernelcore=mirror is specified, ignore movablecore option
7161 if (mirrored_kernelcore) {
7162 bool mem_below_4gb_not_mirrored = false;
7164 for_each_memblock(memory, r) {
7165 if (memblock_is_mirror(r))
7170 usable_startpfn = memblock_region_memory_base_pfn(r);
7172 if (usable_startpfn < 0x100000) {
7173 mem_below_4gb_not_mirrored = true;
7177 zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
7178 min(usable_startpfn, zone_movable_pfn[nid]) :
7182 if (mem_below_4gb_not_mirrored)
7183 pr_warn("This configuration results in unmirrored kernel memory.");
7189 * If kernelcore=nn% or movablecore=nn% was specified, calculate the
7190 * amount of necessary memory.
7192 if (required_kernelcore_percent)
7193 required_kernelcore = (totalpages * 100 * required_kernelcore_percent) /
7195 if (required_movablecore_percent)
7196 required_movablecore = (totalpages * 100 * required_movablecore_percent) /
7200 * If movablecore= was specified, calculate what size of
7201 * kernelcore that corresponds so that memory usable for
7202 * any allocation type is evenly spread. If both kernelcore
7203 * and movablecore are specified, then the value of kernelcore
7204 * will be used for required_kernelcore if it's greater than
7205 * what movablecore would have allowed.
7207 if (required_movablecore) {
7208 unsigned long corepages;
7211 * Round-up so that ZONE_MOVABLE is at least as large as what
7212 * was requested by the user
7214 required_movablecore =
7215 roundup(required_movablecore, MAX_ORDER_NR_PAGES);
7216 required_movablecore = min(totalpages, required_movablecore);
7217 corepages = totalpages - required_movablecore;
7219 required_kernelcore = max(required_kernelcore, corepages);
7223 * If kernelcore was not specified or kernelcore size is larger
7224 * than totalpages, there is no ZONE_MOVABLE.
7226 if (!required_kernelcore || required_kernelcore >= totalpages)
7229 /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
7230 usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
7233 /* Spread kernelcore memory as evenly as possible throughout nodes */
7234 kernelcore_node = required_kernelcore / usable_nodes;
7235 for_each_node_state(nid, N_MEMORY) {
7236 unsigned long start_pfn, end_pfn;
7239 * Recalculate kernelcore_node if the division per node
7240 * now exceeds what is necessary to satisfy the requested
7241 * amount of memory for the kernel
7243 if (required_kernelcore < kernelcore_node)
7244 kernelcore_node = required_kernelcore / usable_nodes;
7247 * As the map is walked, we track how much memory is usable
7248 * by the kernel using kernelcore_remaining. When it is
7249 * 0, the rest of the node is usable by ZONE_MOVABLE
7251 kernelcore_remaining = kernelcore_node;
7253 /* Go through each range of PFNs within this node */
7254 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
7255 unsigned long size_pages;
7257 start_pfn = max(start_pfn, zone_movable_pfn[nid]);
7258 if (start_pfn >= end_pfn)
7261 /* Account for what is only usable for kernelcore */
7262 if (start_pfn < usable_startpfn) {
7263 unsigned long kernel_pages;
7264 kernel_pages = min(end_pfn, usable_startpfn)
7267 kernelcore_remaining -= min(kernel_pages,
7268 kernelcore_remaining);
7269 required_kernelcore -= min(kernel_pages,
7270 required_kernelcore);
7272 /* Continue if range is now fully accounted */
7273 if (end_pfn <= usable_startpfn) {
7276 * Push zone_movable_pfn to the end so
7277 * that if we have to rebalance
7278 * kernelcore across nodes, we will
7279 * not double account here
7281 zone_movable_pfn[nid] = end_pfn;
7284 start_pfn = usable_startpfn;
7288 * The usable PFN range for ZONE_MOVABLE is from
7289 * start_pfn->end_pfn. Calculate size_pages as the
7290 * number of pages used as kernelcore
7292 size_pages = end_pfn - start_pfn;
7293 if (size_pages > kernelcore_remaining)
7294 size_pages = kernelcore_remaining;
7295 zone_movable_pfn[nid] = start_pfn + size_pages;
7298 * Some kernelcore has been met, update counts and
7299 * break if the kernelcore for this node has been
7302 required_kernelcore -= min(required_kernelcore,
7304 kernelcore_remaining -= size_pages;
7305 if (!kernelcore_remaining)
7311 * If there is still required_kernelcore, we do another pass with one
7312 * less node in the count. This will push zone_movable_pfn[nid] further
7313 * along on the nodes that still have memory until kernelcore is
7317 if (usable_nodes && required_kernelcore > usable_nodes)
7321 /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
7322 for (nid = 0; nid < MAX_NUMNODES; nid++)
7323 zone_movable_pfn[nid] =
7324 roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
7327 /* restore the node_state */
7328 node_states[N_MEMORY] = saved_node_state;
7331 /* Any regular or high memory on that node ? */
7332 static void check_for_memory(pg_data_t *pgdat, int nid)
7334 enum zone_type zone_type;
7336 for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
7337 struct zone *zone = &pgdat->node_zones[zone_type];
7338 if (populated_zone(zone)) {
7339 if (IS_ENABLED(CONFIG_HIGHMEM))
7340 node_set_state(nid, N_HIGH_MEMORY);
7341 if (zone_type <= ZONE_NORMAL)
7342 node_set_state(nid, N_NORMAL_MEMORY);
7349 * free_area_init_nodes - Initialise all pg_data_t and zone data
7350 * @max_zone_pfn: an array of max PFNs for each zone
7352 * This will call free_area_init_node() for each active node in the system.
7353 * Using the page ranges provided by memblock_set_node(), the size of each
7354 * zone in each node and their holes is calculated. If the maximum PFN
7355 * between two adjacent zones match, it is assumed that the zone is empty.
7356 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
7357 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
7358 * starts where the previous one ended. For example, ZONE_DMA32 starts
7359 * at arch_max_dma_pfn.
7361 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
7363 unsigned long start_pfn, end_pfn;
7366 /* Record where the zone boundaries are */
7367 memset(arch_zone_lowest_possible_pfn, 0,
7368 sizeof(arch_zone_lowest_possible_pfn));
7369 memset(arch_zone_highest_possible_pfn, 0,
7370 sizeof(arch_zone_highest_possible_pfn));
7372 start_pfn = find_min_pfn_with_active_regions();
7374 for (i = 0; i < MAX_NR_ZONES; i++) {
7375 if (i == ZONE_MOVABLE)
7378 end_pfn = max(max_zone_pfn[i], start_pfn);
7379 arch_zone_lowest_possible_pfn[i] = start_pfn;
7380 arch_zone_highest_possible_pfn[i] = end_pfn;
7382 start_pfn = end_pfn;
7385 /* Find the PFNs that ZONE_MOVABLE begins at in each node */
7386 memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
7387 find_zone_movable_pfns_for_nodes();
7389 /* Print out the zone ranges */
7390 pr_info("Zone ranges:\n");
7391 for (i = 0; i < MAX_NR_ZONES; i++) {
7392 if (i == ZONE_MOVABLE)
7394 pr_info(" %-8s ", zone_names[i]);
7395 if (arch_zone_lowest_possible_pfn[i] ==
7396 arch_zone_highest_possible_pfn[i])
7399 pr_cont("[mem %#018Lx-%#018Lx]\n",
7400 (u64)arch_zone_lowest_possible_pfn[i]
7402 ((u64)arch_zone_highest_possible_pfn[i]
7403 << PAGE_SHIFT) - 1);
7406 /* Print out the PFNs ZONE_MOVABLE begins at in each node */
7407 pr_info("Movable zone start for each node\n");
7408 for (i = 0; i < MAX_NUMNODES; i++) {
7409 if (zone_movable_pfn[i])
7410 pr_info(" Node %d: %#018Lx\n", i,
7411 (u64)zone_movable_pfn[i] << PAGE_SHIFT);
7415 * Print out the early node map, and initialize the
7416 * subsection-map relative to active online memory ranges to
7417 * enable future "sub-section" extensions of the memory map.
7419 pr_info("Early memory node ranges\n");
7420 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
7421 pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid,
7422 (u64)start_pfn << PAGE_SHIFT,
7423 ((u64)end_pfn << PAGE_SHIFT) - 1);
7424 subsection_map_init(start_pfn, end_pfn - start_pfn);
7427 /* Initialise every node */
7428 mminit_verify_pageflags_layout();
7429 setup_nr_node_ids();
7430 init_unavailable_mem();
7431 for_each_online_node(nid) {
7432 pg_data_t *pgdat = NODE_DATA(nid);
7433 free_area_init_node(nid, NULL,
7434 find_min_pfn_for_node(nid), NULL);
7436 /* Any memory on that node */
7437 if (pgdat->node_present_pages)
7438 node_set_state(nid, N_MEMORY);
7439 check_for_memory(pgdat, nid);
7443 static int __init cmdline_parse_core(char *p, unsigned long *core,
7444 unsigned long *percent)
7446 unsigned long long coremem;
7452 /* Value may be a percentage of total memory, otherwise bytes */
7453 coremem = simple_strtoull(p, &endptr, 0);
7454 if (*endptr == '%') {
7455 /* Paranoid check for percent values greater than 100 */
7456 WARN_ON(coremem > 100);
7460 coremem = memparse(p, &p);
7461 /* Paranoid check that UL is enough for the coremem value */
7462 WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
7464 *core = coremem >> PAGE_SHIFT;
7471 * kernelcore=size sets the amount of memory for use for allocations that
7472 * cannot be reclaimed or migrated.
7474 static int __init cmdline_parse_kernelcore(char *p)
7476 /* parse kernelcore=mirror */
7477 if (parse_option_str(p, "mirror")) {
7478 mirrored_kernelcore = true;
7482 return cmdline_parse_core(p, &required_kernelcore,
7483 &required_kernelcore_percent);
7487 * movablecore=size sets the amount of memory for use for allocations that
7488 * can be reclaimed or migrated.
7490 static int __init cmdline_parse_movablecore(char *p)
7492 return cmdline_parse_core(p, &required_movablecore,
7493 &required_movablecore_percent);
7496 early_param("kernelcore", cmdline_parse_kernelcore);
7497 early_param("movablecore", cmdline_parse_movablecore);
7499 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
7501 void adjust_managed_page_count(struct page *page, long count)
7503 atomic_long_add(count, &page_zone(page)->managed_pages);
7504 totalram_pages_add(count);
7505 #ifdef CONFIG_HIGHMEM
7506 if (PageHighMem(page))
7507 totalhigh_pages_add(count);
7510 EXPORT_SYMBOL(adjust_managed_page_count);
7512 unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
7515 unsigned long pages = 0;
7517 start = (void *)PAGE_ALIGN((unsigned long)start);
7518 end = (void *)((unsigned long)end & PAGE_MASK);
7519 for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
7520 struct page *page = virt_to_page(pos);
7521 void *direct_map_addr;
7524 * 'direct_map_addr' might be different from 'pos'
7525 * because some architectures' virt_to_page()
7526 * work with aliases. Getting the direct map
7527 * address ensures that we get a _writeable_
7528 * alias for the memset().
7530 direct_map_addr = page_address(page);
7531 if ((unsigned int)poison <= 0xFF)
7532 memset(direct_map_addr, poison, PAGE_SIZE);
7534 free_reserved_page(page);
7538 pr_info("Freeing %s memory: %ldK\n",
7539 s, pages << (PAGE_SHIFT - 10));
7544 #ifdef CONFIG_HIGHMEM
7545 void free_highmem_page(struct page *page)
7547 __free_reserved_page(page);
7548 totalram_pages_inc();
7549 atomic_long_inc(&page_zone(page)->managed_pages);
7550 totalhigh_pages_inc();
7555 void __init mem_init_print_info(const char *str)
7557 unsigned long physpages, codesize, datasize, rosize, bss_size;
7558 unsigned long init_code_size, init_data_size;
7560 physpages = get_num_physpages();
7561 codesize = _etext - _stext;
7562 datasize = _edata - _sdata;
7563 rosize = __end_rodata - __start_rodata;
7564 bss_size = __bss_stop - __bss_start;
7565 init_data_size = __init_end - __init_begin;
7566 init_code_size = _einittext - _sinittext;
7569 * Detect special cases and adjust section sizes accordingly:
7570 * 1) .init.* may be embedded into .data sections
7571 * 2) .init.text.* may be out of [__init_begin, __init_end],
7572 * please refer to arch/tile/kernel/vmlinux.lds.S.
7573 * 3) .rodata.* may be embedded into .text or .data sections.
7575 #define adj_init_size(start, end, size, pos, adj) \
7577 if (start <= pos && pos < end && size > adj) \
7581 adj_init_size(__init_begin, __init_end, init_data_size,
7582 _sinittext, init_code_size);
7583 adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
7584 adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
7585 adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
7586 adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
7588 #undef adj_init_size
7590 pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
7591 #ifdef CONFIG_HIGHMEM
7595 nr_free_pages() << (PAGE_SHIFT - 10),
7596 physpages << (PAGE_SHIFT - 10),
7597 codesize >> 10, datasize >> 10, rosize >> 10,
7598 (init_data_size + init_code_size) >> 10, bss_size >> 10,
7599 (physpages - totalram_pages() - totalcma_pages) << (PAGE_SHIFT - 10),
7600 totalcma_pages << (PAGE_SHIFT - 10),
7601 #ifdef CONFIG_HIGHMEM
7602 totalhigh_pages() << (PAGE_SHIFT - 10),
7604 str ? ", " : "", str ? str : "");
7608 * set_dma_reserve - set the specified number of pages reserved in the first zone
7609 * @new_dma_reserve: The number of pages to mark reserved
7611 * The per-cpu batchsize and zone watermarks are determined by managed_pages.
7612 * In the DMA zone, a significant percentage may be consumed by kernel image
7613 * and other unfreeable allocations which can skew the watermarks badly. This
7614 * function may optionally be used to account for unfreeable pages in the
7615 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
7616 * smaller per-cpu batchsize.
7618 void __init set_dma_reserve(unsigned long new_dma_reserve)
7620 dma_reserve = new_dma_reserve;
7623 void __init free_area_init(unsigned long *zones_size)
7625 init_unavailable_mem();
7626 free_area_init_node(0, zones_size,
7627 __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
7630 static int page_alloc_cpu_dead(unsigned int cpu)
7633 lru_add_drain_cpu(cpu);
7637 * Spill the event counters of the dead processor
7638 * into the current processors event counters.
7639 * This artificially elevates the count of the current
7642 vm_events_fold_cpu(cpu);
7645 * Zero the differential counters of the dead processor
7646 * so that the vm statistics are consistent.
7648 * This is only okay since the processor is dead and cannot
7649 * race with what we are doing.
7651 cpu_vm_stats_fold(cpu);
7656 int hashdist = HASHDIST_DEFAULT;
7658 static int __init set_hashdist(char *str)
7662 hashdist = simple_strtoul(str, &str, 0);
7665 __setup("hashdist=", set_hashdist);
7668 void __init page_alloc_init(void)
7673 if (num_node_state(N_MEMORY) == 1)
7677 ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC_DEAD,
7678 "mm/page_alloc:dead", NULL,
7679 page_alloc_cpu_dead);
7684 * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio
7685 * or min_free_kbytes changes.
7687 static void calculate_totalreserve_pages(void)
7689 struct pglist_data *pgdat;
7690 unsigned long reserve_pages = 0;
7691 enum zone_type i, j;
7693 for_each_online_pgdat(pgdat) {
7695 pgdat->totalreserve_pages = 0;
7697 for (i = 0; i < MAX_NR_ZONES; i++) {
7698 struct zone *zone = pgdat->node_zones + i;
7700 unsigned long managed_pages = zone_managed_pages(zone);
7702 /* Find valid and maximum lowmem_reserve in the zone */
7703 for (j = i; j < MAX_NR_ZONES; j++) {
7704 if (zone->lowmem_reserve[j] > max)
7705 max = zone->lowmem_reserve[j];
7708 /* we treat the high watermark as reserved pages. */
7709 max += high_wmark_pages(zone);
7711 if (max > managed_pages)
7712 max = managed_pages;
7714 pgdat->totalreserve_pages += max;
7716 reserve_pages += max;
7719 totalreserve_pages = reserve_pages;
7723 * setup_per_zone_lowmem_reserve - called whenever
7724 * sysctl_lowmem_reserve_ratio changes. Ensures that each zone
7725 * has a correct pages reserved value, so an adequate number of
7726 * pages are left in the zone after a successful __alloc_pages().
7728 static void setup_per_zone_lowmem_reserve(void)
7730 struct pglist_data *pgdat;
7731 enum zone_type j, idx;
7733 for_each_online_pgdat(pgdat) {
7734 for (j = 0; j < MAX_NR_ZONES; j++) {
7735 struct zone *zone = pgdat->node_zones + j;
7736 unsigned long managed_pages = zone_managed_pages(zone);
7738 zone->lowmem_reserve[j] = 0;
7742 struct zone *lower_zone;
7745 lower_zone = pgdat->node_zones + idx;
7747 if (sysctl_lowmem_reserve_ratio[idx] < 1) {
7748 sysctl_lowmem_reserve_ratio[idx] = 0;
7749 lower_zone->lowmem_reserve[j] = 0;
7751 lower_zone->lowmem_reserve[j] =
7752 managed_pages / sysctl_lowmem_reserve_ratio[idx];
7754 managed_pages += zone_managed_pages(lower_zone);
7759 /* update totalreserve_pages */
7760 calculate_totalreserve_pages();
7763 static void __setup_per_zone_wmarks(void)
7765 unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
7766 unsigned long lowmem_pages = 0;
7768 unsigned long flags;
7770 /* Calculate total number of !ZONE_HIGHMEM pages */
7771 for_each_zone(zone) {
7772 if (!is_highmem(zone))
7773 lowmem_pages += zone_managed_pages(zone);
7776 for_each_zone(zone) {
7779 spin_lock_irqsave(&zone->lock, flags);
7780 tmp = (u64)pages_min * zone_managed_pages(zone);
7781 do_div(tmp, lowmem_pages);
7782 if (is_highmem(zone)) {
7784 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
7785 * need highmem pages, so cap pages_min to a small
7788 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
7789 * deltas control async page reclaim, and so should
7790 * not be capped for highmem.
7792 unsigned long min_pages;
7794 min_pages = zone_managed_pages(zone) / 1024;
7795 min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
7796 zone->_watermark[WMARK_MIN] = min_pages;
7799 * If it's a lowmem zone, reserve a number of pages
7800 * proportionate to the zone's size.
7802 zone->_watermark[WMARK_MIN] = tmp;
7806 * Set the kswapd watermarks distance according to the
7807 * scale factor in proportion to available memory, but
7808 * ensure a minimum size on small systems.
7810 tmp = max_t(u64, tmp >> 2,
7811 mult_frac(zone_managed_pages(zone),
7812 watermark_scale_factor, 10000));
7814 zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp;
7815 zone->_watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;
7816 zone->watermark_boost = 0;
7818 spin_unlock_irqrestore(&zone->lock, flags);
7821 /* update totalreserve_pages */
7822 calculate_totalreserve_pages();
7826 * setup_per_zone_wmarks - called when min_free_kbytes changes
7827 * or when memory is hot-{added|removed}
7829 * Ensures that the watermark[min,low,high] values for each zone are set
7830 * correctly with respect to min_free_kbytes.
7832 void setup_per_zone_wmarks(void)
7834 static DEFINE_SPINLOCK(lock);
7837 __setup_per_zone_wmarks();
7842 * Initialise min_free_kbytes.
7844 * For small machines we want it small (128k min). For large machines
7845 * we want it large (64MB max). But it is not linear, because network
7846 * bandwidth does not increase linearly with machine size. We use
7848 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
7849 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
7865 int __meminit init_per_zone_wmark_min(void)
7867 unsigned long lowmem_kbytes;
7868 int new_min_free_kbytes;
7870 lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
7871 new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
7873 if (new_min_free_kbytes > user_min_free_kbytes) {
7874 min_free_kbytes = new_min_free_kbytes;
7875 if (min_free_kbytes < 128)
7876 min_free_kbytes = 128;
7877 if (min_free_kbytes > 262144)
7878 min_free_kbytes = 262144;
7880 pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
7881 new_min_free_kbytes, user_min_free_kbytes);
7883 setup_per_zone_wmarks();
7884 refresh_zone_stat_thresholds();
7885 setup_per_zone_lowmem_reserve();
7888 setup_min_unmapped_ratio();
7889 setup_min_slab_ratio();
7894 core_initcall(init_per_zone_wmark_min)
7897 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
7898 * that we can call two helper functions whenever min_free_kbytes
7901 int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
7902 void __user *buffer, size_t *length, loff_t *ppos)
7906 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7911 user_min_free_kbytes = min_free_kbytes;
7912 setup_per_zone_wmarks();
7917 int watermark_boost_factor_sysctl_handler(struct ctl_table *table, int write,
7918 void __user *buffer, size_t *length, loff_t *ppos)
7922 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7929 int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
7930 void __user *buffer, size_t *length, loff_t *ppos)
7934 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7939 setup_per_zone_wmarks();
7945 static void setup_min_unmapped_ratio(void)
7950 for_each_online_pgdat(pgdat)
7951 pgdat->min_unmapped_pages = 0;
7954 zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) *
7955 sysctl_min_unmapped_ratio) / 100;
7959 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
7960 void __user *buffer, size_t *length, loff_t *ppos)
7964 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7968 setup_min_unmapped_ratio();
7973 static void setup_min_slab_ratio(void)
7978 for_each_online_pgdat(pgdat)
7979 pgdat->min_slab_pages = 0;
7982 zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) *
7983 sysctl_min_slab_ratio) / 100;
7986 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
7987 void __user *buffer, size_t *length, loff_t *ppos)
7991 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7995 setup_min_slab_ratio();
8002 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
8003 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
8004 * whenever sysctl_lowmem_reserve_ratio changes.
8006 * The reserve ratio obviously has absolutely no relation with the
8007 * minimum watermarks. The lowmem reserve ratio can only make sense
8008 * if in function of the boot time zone sizes.
8010 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
8011 void __user *buffer, size_t *length, loff_t *ppos)
8013 proc_dointvec_minmax(table, write, buffer, length, ppos);
8014 setup_per_zone_lowmem_reserve();
8018 static void __zone_pcp_update(struct zone *zone)
8022 for_each_possible_cpu(cpu)
8023 pageset_set_high_and_batch(zone,
8024 per_cpu_ptr(zone->pageset, cpu));
8028 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
8029 * cpu. It is the fraction of total pages in each zone that a hot per cpu
8030 * pagelist can have before it gets flushed back to buddy allocator.
8032 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write,
8033 void __user *buffer, size_t *length, loff_t *ppos)
8036 int old_percpu_pagelist_fraction;
8039 mutex_lock(&pcp_batch_high_lock);
8040 old_percpu_pagelist_fraction = percpu_pagelist_fraction;
8042 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
8043 if (!write || ret < 0)
8046 /* Sanity checking to avoid pcp imbalance */
8047 if (percpu_pagelist_fraction &&
8048 percpu_pagelist_fraction < MIN_PERCPU_PAGELIST_FRACTION) {
8049 percpu_pagelist_fraction = old_percpu_pagelist_fraction;
8055 if (percpu_pagelist_fraction == old_percpu_pagelist_fraction)
8058 for_each_populated_zone(zone)
8059 __zone_pcp_update(zone);
8061 mutex_unlock(&pcp_batch_high_lock);
8065 #ifndef __HAVE_ARCH_RESERVED_KERNEL_PAGES
8067 * Returns the number of pages that arch has reserved but
8068 * is not known to alloc_large_system_hash().
8070 static unsigned long __init arch_reserved_kernel_pages(void)
8077 * Adaptive scale is meant to reduce sizes of hash tables on large memory
8078 * machines. As memory size is increased the scale is also increased but at
8079 * slower pace. Starting from ADAPT_SCALE_BASE (64G), every time memory
8080 * quadruples the scale is increased by one, which means the size of hash table
8081 * only doubles, instead of quadrupling as well.
8082 * Because 32-bit systems cannot have large physical memory, where this scaling
8083 * makes sense, it is disabled on such platforms.
8085 #if __BITS_PER_LONG > 32
8086 #define ADAPT_SCALE_BASE (64ul << 30)
8087 #define ADAPT_SCALE_SHIFT 2
8088 #define ADAPT_SCALE_NPAGES (ADAPT_SCALE_BASE >> PAGE_SHIFT)
8092 * allocate a large system hash table from bootmem
8093 * - it is assumed that the hash table must contain an exact power-of-2
8094 * quantity of entries
8095 * - limit is the number of hash buckets, not the total allocation size
8097 void *__init alloc_large_system_hash(const char *tablename,
8098 unsigned long bucketsize,
8099 unsigned long numentries,
8102 unsigned int *_hash_shift,
8103 unsigned int *_hash_mask,
8104 unsigned long low_limit,
8105 unsigned long high_limit)
8107 unsigned long long max = high_limit;
8108 unsigned long log2qty, size;
8113 /* allow the kernel cmdline to have a say */
8115 /* round applicable memory size up to nearest megabyte */
8116 numentries = nr_kernel_pages;
8117 numentries -= arch_reserved_kernel_pages();
8119 /* It isn't necessary when PAGE_SIZE >= 1MB */
8120 if (PAGE_SHIFT < 20)
8121 numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
8123 #if __BITS_PER_LONG > 32
8125 unsigned long adapt;
8127 for (adapt = ADAPT_SCALE_NPAGES; adapt < numentries;
8128 adapt <<= ADAPT_SCALE_SHIFT)
8133 /* limit to 1 bucket per 2^scale bytes of low memory */
8134 if (scale > PAGE_SHIFT)
8135 numentries >>= (scale - PAGE_SHIFT);
8137 numentries <<= (PAGE_SHIFT - scale);
8139 /* Make sure we've got at least a 0-order allocation.. */
8140 if (unlikely(flags & HASH_SMALL)) {
8141 /* Makes no sense without HASH_EARLY */
8142 WARN_ON(!(flags & HASH_EARLY));
8143 if (!(numentries >> *_hash_shift)) {
8144 numentries = 1UL << *_hash_shift;
8145 BUG_ON(!numentries);
8147 } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
8148 numentries = PAGE_SIZE / bucketsize;
8150 numentries = roundup_pow_of_two(numentries);
8152 /* limit allocation size to 1/16 total memory by default */
8154 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
8155 do_div(max, bucketsize);
8157 max = min(max, 0x80000000ULL);
8159 if (numentries < low_limit)
8160 numentries = low_limit;
8161 if (numentries > max)
8164 log2qty = ilog2(numentries);
8166 gfp_flags = (flags & HASH_ZERO) ? GFP_ATOMIC | __GFP_ZERO : GFP_ATOMIC;
8169 size = bucketsize << log2qty;
8170 if (flags & HASH_EARLY) {
8171 if (flags & HASH_ZERO)
8172 table = memblock_alloc(size, SMP_CACHE_BYTES);
8174 table = memblock_alloc_raw(size,
8176 } else if (get_order(size) >= MAX_ORDER || hashdist) {
8177 table = __vmalloc(size, gfp_flags, PAGE_KERNEL);
8181 * If bucketsize is not a power-of-two, we may free
8182 * some pages at the end of hash table which
8183 * alloc_pages_exact() automatically does
8185 table = alloc_pages_exact(size, gfp_flags);
8186 kmemleak_alloc(table, size, 1, gfp_flags);
8188 } while (!table && size > PAGE_SIZE && --log2qty);
8191 panic("Failed to allocate %s hash table\n", tablename);
8193 pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
8194 tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
8195 virt ? "vmalloc" : "linear");
8198 *_hash_shift = log2qty;
8200 *_hash_mask = (1 << log2qty) - 1;
8206 * This function checks whether pageblock includes unmovable pages or not.
8208 * PageLRU check without isolation or lru_lock could race so that
8209 * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
8210 * check without lock_page also may miss some movable non-lru pages at
8211 * race condition. So you can't expect this function should be exact.
8213 * Returns a page without holding a reference. If the caller wants to
8214 * dereference that page (e.g., dumping), it has to make sure that that it
8215 * cannot get removed (e.g., via memory unplug) concurrently.
8218 struct page *has_unmovable_pages(struct zone *zone, struct page *page,
8219 int migratetype, int flags)
8221 unsigned long iter = 0;
8222 unsigned long pfn = page_to_pfn(page);
8225 * TODO we could make this much more efficient by not checking every
8226 * page in the range if we know all of them are in MOVABLE_ZONE and
8227 * that the movable zone guarantees that pages are migratable but
8228 * the later is not the case right now unfortunatelly. E.g. movablecore
8229 * can still lead to having bootmem allocations in zone_movable.
8232 if (is_migrate_cma_page(page)) {
8234 * CMA allocations (alloc_contig_range) really need to mark
8235 * isolate CMA pageblocks even when they are not movable in fact
8236 * so consider them movable here.
8238 if (is_migrate_cma(migratetype))
8244 for (; iter < pageblock_nr_pages; iter++) {
8245 if (!pfn_valid_within(pfn + iter))
8248 page = pfn_to_page(pfn + iter);
8250 if (PageReserved(page))
8254 * If the zone is movable and we have ruled out all reserved
8255 * pages then it should be reasonably safe to assume the rest
8258 if (zone_idx(zone) == ZONE_MOVABLE)
8262 * Hugepages are not in LRU lists, but they're movable.
8263 * We need not scan over tail pages because we don't
8264 * handle each tail page individually in migration.
8266 if (PageHuge(page)) {
8267 struct page *head = compound_head(page);
8268 unsigned int skip_pages;
8270 if (!hugepage_migration_supported(page_hstate(head)))
8273 skip_pages = compound_nr(head) - (page - head);
8274 iter += skip_pages - 1;
8279 * We can't use page_count without pin a page
8280 * because another CPU can free compound page.
8281 * This check already skips compound tails of THP
8282 * because their page->_refcount is zero at all time.
8284 if (!page_ref_count(page)) {
8285 if (PageBuddy(page))
8286 iter += (1 << page_order(page)) - 1;
8291 * The HWPoisoned page may be not in buddy system, and
8292 * page_count() is not 0.
8294 if ((flags & MEMORY_OFFLINE) && PageHWPoison(page))
8297 if (__PageMovable(page) || PageLRU(page))
8301 * If there are RECLAIMABLE pages, we need to check
8302 * it. But now, memory offline itself doesn't call
8303 * shrink_node_slabs() and it still to be fixed.
8306 * If the page is not RAM, page_count()should be 0.
8307 * we don't need more check. This is an _used_ not-movable page.
8309 * The problematic thing here is PG_reserved pages. PG_reserved
8310 * is set to both of a memory hole page and a _used_ kernel
8318 #ifdef CONFIG_CONTIG_ALLOC
8319 static unsigned long pfn_max_align_down(unsigned long pfn)
8321 return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
8322 pageblock_nr_pages) - 1);
8325 static unsigned long pfn_max_align_up(unsigned long pfn)
8327 return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
8328 pageblock_nr_pages));
8331 /* [start, end) must belong to a single zone. */
8332 static int __alloc_contig_migrate_range(struct compact_control *cc,
8333 unsigned long start, unsigned long end)
8335 /* This function is based on compact_zone() from compaction.c. */
8336 unsigned long nr_reclaimed;
8337 unsigned long pfn = start;
8338 unsigned int tries = 0;
8343 while (pfn < end || !list_empty(&cc->migratepages)) {
8344 if (fatal_signal_pending(current)) {
8349 if (list_empty(&cc->migratepages)) {
8350 cc->nr_migratepages = 0;
8351 pfn = isolate_migratepages_range(cc, pfn, end);
8357 } else if (++tries == 5) {
8358 ret = ret < 0 ? ret : -EBUSY;
8362 nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
8364 cc->nr_migratepages -= nr_reclaimed;
8366 ret = migrate_pages(&cc->migratepages, alloc_migrate_target,
8367 NULL, 0, cc->mode, MR_CONTIG_RANGE);
8370 putback_movable_pages(&cc->migratepages);
8377 * alloc_contig_range() -- tries to allocate given range of pages
8378 * @start: start PFN to allocate
8379 * @end: one-past-the-last PFN to allocate
8380 * @migratetype: migratetype of the underlaying pageblocks (either
8381 * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks
8382 * in range must have the same migratetype and it must
8383 * be either of the two.
8384 * @gfp_mask: GFP mask to use during compaction
8386 * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
8387 * aligned. The PFN range must belong to a single zone.
8389 * The first thing this routine does is attempt to MIGRATE_ISOLATE all
8390 * pageblocks in the range. Once isolated, the pageblocks should not
8391 * be modified by others.
8393 * Return: zero on success or negative error code. On success all
8394 * pages which PFN is in [start, end) are allocated for the caller and
8395 * need to be freed with free_contig_range().
8397 int alloc_contig_range(unsigned long start, unsigned long end,
8398 unsigned migratetype, gfp_t gfp_mask)
8400 unsigned long outer_start, outer_end;
8404 struct compact_control cc = {
8405 .nr_migratepages = 0,
8407 .zone = page_zone(pfn_to_page(start)),
8408 .mode = MIGRATE_SYNC,
8409 .ignore_skip_hint = true,
8410 .no_set_skip_hint = true,
8411 .gfp_mask = current_gfp_context(gfp_mask),
8413 INIT_LIST_HEAD(&cc.migratepages);
8416 * What we do here is we mark all pageblocks in range as
8417 * MIGRATE_ISOLATE. Because pageblock and max order pages may
8418 * have different sizes, and due to the way page allocator
8419 * work, we align the range to biggest of the two pages so
8420 * that page allocator won't try to merge buddies from
8421 * different pageblocks and change MIGRATE_ISOLATE to some
8422 * other migration type.
8424 * Once the pageblocks are marked as MIGRATE_ISOLATE, we
8425 * migrate the pages from an unaligned range (ie. pages that
8426 * we are interested in). This will put all the pages in
8427 * range back to page allocator as MIGRATE_ISOLATE.
8429 * When this is done, we take the pages in range from page
8430 * allocator removing them from the buddy system. This way
8431 * page allocator will never consider using them.
8433 * This lets us mark the pageblocks back as
8434 * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
8435 * aligned range but not in the unaligned, original range are
8436 * put back to page allocator so that buddy can use them.
8439 ret = start_isolate_page_range(pfn_max_align_down(start),
8440 pfn_max_align_up(end), migratetype, 0);
8445 * In case of -EBUSY, we'd like to know which page causes problem.
8446 * So, just fall through. test_pages_isolated() has a tracepoint
8447 * which will report the busy page.
8449 * It is possible that busy pages could become available before
8450 * the call to test_pages_isolated, and the range will actually be
8451 * allocated. So, if we fall through be sure to clear ret so that
8452 * -EBUSY is not accidentally used or returned to caller.
8454 ret = __alloc_contig_migrate_range(&cc, start, end);
8455 if (ret && ret != -EBUSY)
8460 * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
8461 * aligned blocks that are marked as MIGRATE_ISOLATE. What's
8462 * more, all pages in [start, end) are free in page allocator.
8463 * What we are going to do is to allocate all pages from
8464 * [start, end) (that is remove them from page allocator).
8466 * The only problem is that pages at the beginning and at the
8467 * end of interesting range may be not aligned with pages that
8468 * page allocator holds, ie. they can be part of higher order
8469 * pages. Because of this, we reserve the bigger range and
8470 * once this is done free the pages we are not interested in.
8472 * We don't have to hold zone->lock here because the pages are
8473 * isolated thus they won't get removed from buddy.
8476 lru_add_drain_all();
8479 outer_start = start;
8480 while (!PageBuddy(pfn_to_page(outer_start))) {
8481 if (++order >= MAX_ORDER) {
8482 outer_start = start;
8485 outer_start &= ~0UL << order;
8488 if (outer_start != start) {
8489 order = page_order(pfn_to_page(outer_start));
8492 * outer_start page could be small order buddy page and
8493 * it doesn't include start page. Adjust outer_start
8494 * in this case to report failed page properly
8495 * on tracepoint in test_pages_isolated()
8497 if (outer_start + (1UL << order) <= start)
8498 outer_start = start;
8501 /* Make sure the range is really isolated. */
8502 if (test_pages_isolated(outer_start, end, 0)) {
8503 pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n",
8504 __func__, outer_start, end);
8509 /* Grab isolated pages from freelists. */
8510 outer_end = isolate_freepages_range(&cc, outer_start, end);
8516 /* Free head and tail (if any) */
8517 if (start != outer_start)
8518 free_contig_range(outer_start, start - outer_start);
8519 if (end != outer_end)
8520 free_contig_range(end, outer_end - end);
8523 undo_isolate_page_range(pfn_max_align_down(start),
8524 pfn_max_align_up(end), migratetype);
8528 static int __alloc_contig_pages(unsigned long start_pfn,
8529 unsigned long nr_pages, gfp_t gfp_mask)
8531 unsigned long end_pfn = start_pfn + nr_pages;
8533 return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
8537 static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
8538 unsigned long nr_pages)
8540 unsigned long i, end_pfn = start_pfn + nr_pages;
8543 for (i = start_pfn; i < end_pfn; i++) {
8544 page = pfn_to_online_page(i);
8548 if (page_zone(page) != z)
8551 if (PageReserved(page))
8554 if (page_count(page) > 0)
8563 static bool zone_spans_last_pfn(const struct zone *zone,
8564 unsigned long start_pfn, unsigned long nr_pages)
8566 unsigned long last_pfn = start_pfn + nr_pages - 1;
8568 return zone_spans_pfn(zone, last_pfn);
8572 * alloc_contig_pages() -- tries to find and allocate contiguous range of pages
8573 * @nr_pages: Number of contiguous pages to allocate
8574 * @gfp_mask: GFP mask to limit search and used during compaction
8576 * @nodemask: Mask for other possible nodes
8578 * This routine is a wrapper around alloc_contig_range(). It scans over zones
8579 * on an applicable zonelist to find a contiguous pfn range which can then be
8580 * tried for allocation with alloc_contig_range(). This routine is intended
8581 * for allocation requests which can not be fulfilled with the buddy allocator.
8583 * The allocated memory is always aligned to a page boundary. If nr_pages is a
8584 * power of two then the alignment is guaranteed to be to the given nr_pages
8585 * (e.g. 1GB request would be aligned to 1GB).
8587 * Allocated pages can be freed with free_contig_range() or by manually calling
8588 * __free_page() on each allocated page.
8590 * Return: pointer to contiguous pages on success, or NULL if not successful.
8592 struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask,
8593 int nid, nodemask_t *nodemask)
8595 unsigned long ret, pfn, flags;
8596 struct zonelist *zonelist;
8600 zonelist = node_zonelist(nid, gfp_mask);
8601 for_each_zone_zonelist_nodemask(zone, z, zonelist,
8602 gfp_zone(gfp_mask), nodemask) {
8603 spin_lock_irqsave(&zone->lock, flags);
8605 pfn = ALIGN(zone->zone_start_pfn, nr_pages);
8606 while (zone_spans_last_pfn(zone, pfn, nr_pages)) {
8607 if (pfn_range_valid_contig(zone, pfn, nr_pages)) {
8609 * We release the zone lock here because
8610 * alloc_contig_range() will also lock the zone
8611 * at some point. If there's an allocation
8612 * spinning on this lock, it may win the race
8613 * and cause alloc_contig_range() to fail...
8615 spin_unlock_irqrestore(&zone->lock, flags);
8616 ret = __alloc_contig_pages(pfn, nr_pages,
8619 return pfn_to_page(pfn);
8620 spin_lock_irqsave(&zone->lock, flags);
8624 spin_unlock_irqrestore(&zone->lock, flags);
8628 #endif /* CONFIG_CONTIG_ALLOC */
8630 void free_contig_range(unsigned long pfn, unsigned int nr_pages)
8632 unsigned int count = 0;
8634 for (; nr_pages--; pfn++) {
8635 struct page *page = pfn_to_page(pfn);
8637 count += page_count(page) != 1;
8640 WARN(count != 0, "%d pages are still in use!\n", count);
8644 * The zone indicated has a new number of managed_pages; batch sizes and percpu
8645 * page high values need to be recalulated.
8647 void __meminit zone_pcp_update(struct zone *zone)
8649 mutex_lock(&pcp_batch_high_lock);
8650 __zone_pcp_update(zone);
8651 mutex_unlock(&pcp_batch_high_lock);
8654 void zone_pcp_reset(struct zone *zone)
8656 unsigned long flags;
8658 struct per_cpu_pageset *pset;
8660 /* avoid races with drain_pages() */
8661 local_irq_save(flags);
8662 if (zone->pageset != &boot_pageset) {
8663 for_each_online_cpu(cpu) {
8664 pset = per_cpu_ptr(zone->pageset, cpu);
8665 drain_zonestat(zone, pset);
8667 free_percpu(zone->pageset);
8668 zone->pageset = &boot_pageset;
8670 local_irq_restore(flags);
8673 #ifdef CONFIG_MEMORY_HOTREMOVE
8675 * All pages in the range must be in a single zone and isolated
8676 * before calling this.
8679 __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
8685 unsigned long flags;
8686 unsigned long offlined_pages = 0;
8688 /* find the first valid pfn */
8689 for (pfn = start_pfn; pfn < end_pfn; pfn++)
8693 return offlined_pages;
8695 offline_mem_sections(pfn, end_pfn);
8696 zone = page_zone(pfn_to_page(pfn));
8697 spin_lock_irqsave(&zone->lock, flags);
8699 while (pfn < end_pfn) {
8700 if (!pfn_valid(pfn)) {
8704 page = pfn_to_page(pfn);
8706 * The HWPoisoned page may be not in buddy system, and
8707 * page_count() is not 0.
8709 if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
8715 BUG_ON(page_count(page));
8716 BUG_ON(!PageBuddy(page));
8717 order = page_order(page);
8718 offlined_pages += 1 << order;
8719 del_page_from_free_area(page, &zone->free_area[order]);
8720 pfn += (1 << order);
8722 spin_unlock_irqrestore(&zone->lock, flags);
8724 return offlined_pages;
8728 bool is_free_buddy_page(struct page *page)
8730 struct zone *zone = page_zone(page);
8731 unsigned long pfn = page_to_pfn(page);
8732 unsigned long flags;
8735 spin_lock_irqsave(&zone->lock, flags);
8736 for (order = 0; order < MAX_ORDER; order++) {
8737 struct page *page_head = page - (pfn & ((1 << order) - 1));
8739 if (PageBuddy(page_head) && page_order(page_head) >= order)
8742 spin_unlock_irqrestore(&zone->lock, flags);
8744 return order < MAX_ORDER;
8747 #ifdef CONFIG_MEMORY_FAILURE
8749 * Set PG_hwpoison flag if a given page is confirmed to be a free page. This
8750 * test is performed under the zone lock to prevent a race against page
8753 bool set_hwpoison_free_buddy_page(struct page *page)
8755 struct zone *zone = page_zone(page);
8756 unsigned long pfn = page_to_pfn(page);
8757 unsigned long flags;
8759 bool hwpoisoned = false;
8761 spin_lock_irqsave(&zone->lock, flags);
8762 for (order = 0; order < MAX_ORDER; order++) {
8763 struct page *page_head = page - (pfn & ((1 << order) - 1));
8765 if (PageBuddy(page_head) && page_order(page_head) >= order) {
8766 if (!TestSetPageHWPoison(page))
8771 spin_unlock_irqrestore(&zone->lock, flags);