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>
71 #include <linux/padata.h>
72 #include <linux/khugepaged.h>
74 #include <asm/sections.h>
75 #include <asm/tlbflush.h>
76 #include <asm/div64.h>
79 #include "page_reporting.h"
81 /* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */
82 typedef int __bitwise fpi_t;
84 /* No special request */
85 #define FPI_NONE ((__force fpi_t)0)
88 * Skip free page reporting notification for the (possibly merged) page.
89 * This does not hinder free page reporting from grabbing the page,
90 * reporting it and marking it "reported" - it only skips notifying
91 * the free page reporting infrastructure about a newly freed page. For
92 * example, used when temporarily pulling a page from a freelist and
93 * putting it back unmodified.
95 #define FPI_SKIP_REPORT_NOTIFY ((__force fpi_t)BIT(0))
98 * Place the (possibly merged) page to the tail of the freelist. Will ignore
99 * page shuffling (relevant code - e.g., memory onlining - is expected to
100 * shuffle the whole zone).
102 * Note: No code should rely on this flag for correctness - it's purely
103 * to allow for optimizations when handing back either fresh pages
104 * (memory onlining) or untouched pages (page isolation, free page
107 #define FPI_TO_TAIL ((__force fpi_t)BIT(1))
109 /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
110 static DEFINE_MUTEX(pcp_batch_high_lock);
111 #define MIN_PERCPU_PAGELIST_FRACTION (8)
113 #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
114 DEFINE_PER_CPU(int, numa_node);
115 EXPORT_PER_CPU_SYMBOL(numa_node);
118 DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key);
120 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
122 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
123 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
124 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
125 * defined in <linux/topology.h>.
127 DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */
128 EXPORT_PER_CPU_SYMBOL(_numa_mem_);
131 /* work_structs for global per-cpu drains */
134 struct work_struct work;
136 static DEFINE_MUTEX(pcpu_drain_mutex);
137 static DEFINE_PER_CPU(struct pcpu_drain, pcpu_drain);
139 #ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
140 volatile unsigned long latent_entropy __latent_entropy;
141 EXPORT_SYMBOL(latent_entropy);
145 * Array of node states.
147 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
148 [N_POSSIBLE] = NODE_MASK_ALL,
149 [N_ONLINE] = { { [0] = 1UL } },
151 [N_NORMAL_MEMORY] = { { [0] = 1UL } },
152 #ifdef CONFIG_HIGHMEM
153 [N_HIGH_MEMORY] = { { [0] = 1UL } },
155 [N_MEMORY] = { { [0] = 1UL } },
156 [N_CPU] = { { [0] = 1UL } },
159 EXPORT_SYMBOL(node_states);
161 atomic_long_t _totalram_pages __read_mostly;
162 EXPORT_SYMBOL(_totalram_pages);
163 unsigned long totalreserve_pages __read_mostly;
164 unsigned long totalcma_pages __read_mostly;
166 int percpu_pagelist_fraction;
167 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
168 #ifdef CONFIG_INIT_ON_ALLOC_DEFAULT_ON
169 DEFINE_STATIC_KEY_TRUE(init_on_alloc);
171 DEFINE_STATIC_KEY_FALSE(init_on_alloc);
173 EXPORT_SYMBOL(init_on_alloc);
175 #ifdef CONFIG_INIT_ON_FREE_DEFAULT_ON
176 DEFINE_STATIC_KEY_TRUE(init_on_free);
178 DEFINE_STATIC_KEY_FALSE(init_on_free);
180 EXPORT_SYMBOL(init_on_free);
182 static int __init early_init_on_alloc(char *buf)
187 ret = kstrtobool(buf, &bool_result);
190 if (bool_result && page_poisoning_enabled())
191 pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_alloc\n");
193 static_branch_enable(&init_on_alloc);
195 static_branch_disable(&init_on_alloc);
198 early_param("init_on_alloc", early_init_on_alloc);
200 static int __init early_init_on_free(char *buf)
205 ret = kstrtobool(buf, &bool_result);
208 if (bool_result && page_poisoning_enabled())
209 pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_free\n");
211 static_branch_enable(&init_on_free);
213 static_branch_disable(&init_on_free);
216 early_param("init_on_free", early_init_on_free);
219 * A cached value of the page's pageblock's migratetype, used when the page is
220 * put on a pcplist. Used to avoid the pageblock migratetype lookup when
221 * freeing from pcplists in most cases, at the cost of possibly becoming stale.
222 * Also the migratetype set in the page does not necessarily match the pcplist
223 * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
224 * other index - this ensures that it will be put on the correct CMA freelist.
226 static inline int get_pcppage_migratetype(struct page *page)
231 static inline void set_pcppage_migratetype(struct page *page, int migratetype)
233 page->index = migratetype;
236 #ifdef CONFIG_PM_SLEEP
238 * The following functions are used by the suspend/hibernate code to temporarily
239 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
240 * while devices are suspended. To avoid races with the suspend/hibernate code,
241 * they should always be called with system_transition_mutex held
242 * (gfp_allowed_mask also should only be modified with system_transition_mutex
243 * held, unless the suspend/hibernate code is guaranteed not to run in parallel
244 * with that modification).
247 static gfp_t saved_gfp_mask;
249 void pm_restore_gfp_mask(void)
251 WARN_ON(!mutex_is_locked(&system_transition_mutex));
252 if (saved_gfp_mask) {
253 gfp_allowed_mask = saved_gfp_mask;
258 void pm_restrict_gfp_mask(void)
260 WARN_ON(!mutex_is_locked(&system_transition_mutex));
261 WARN_ON(saved_gfp_mask);
262 saved_gfp_mask = gfp_allowed_mask;
263 gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
266 bool pm_suspended_storage(void)
268 if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS))
272 #endif /* CONFIG_PM_SLEEP */
274 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
275 unsigned int pageblock_order __read_mostly;
278 static void __free_pages_ok(struct page *page, unsigned int order,
282 * results with 256, 32 in the lowmem_reserve sysctl:
283 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
284 * 1G machine -> (16M dma, 784M normal, 224M high)
285 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
286 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
287 * HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA
289 * TBD: should special case ZONE_DMA32 machines here - in those we normally
290 * don't need any ZONE_NORMAL reservation
292 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = {
293 #ifdef CONFIG_ZONE_DMA
296 #ifdef CONFIG_ZONE_DMA32
300 #ifdef CONFIG_HIGHMEM
306 static char * const zone_names[MAX_NR_ZONES] = {
307 #ifdef CONFIG_ZONE_DMA
310 #ifdef CONFIG_ZONE_DMA32
314 #ifdef CONFIG_HIGHMEM
318 #ifdef CONFIG_ZONE_DEVICE
323 const char * const migratetype_names[MIGRATE_TYPES] = {
331 #ifdef CONFIG_MEMORY_ISOLATION
336 compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = {
337 [NULL_COMPOUND_DTOR] = NULL,
338 [COMPOUND_PAGE_DTOR] = free_compound_page,
339 #ifdef CONFIG_HUGETLB_PAGE
340 [HUGETLB_PAGE_DTOR] = free_huge_page,
342 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
343 [TRANSHUGE_PAGE_DTOR] = free_transhuge_page,
347 int min_free_kbytes = 1024;
348 int user_min_free_kbytes = -1;
349 #ifdef CONFIG_DISCONTIGMEM
351 * DiscontigMem defines memory ranges as separate pg_data_t even if the ranges
352 * are not on separate NUMA nodes. Functionally this works but with
353 * watermark_boost_factor, it can reclaim prematurely as the ranges can be
354 * quite small. By default, do not boost watermarks on discontigmem as in
355 * many cases very high-order allocations like THP are likely to be
356 * unsupported and the premature reclaim offsets the advantage of long-term
357 * fragmentation avoidance.
359 int watermark_boost_factor __read_mostly;
361 int watermark_boost_factor __read_mostly = 15000;
363 int watermark_scale_factor = 10;
365 static unsigned long nr_kernel_pages __initdata;
366 static unsigned long nr_all_pages __initdata;
367 static unsigned long dma_reserve __initdata;
369 static unsigned long arch_zone_lowest_possible_pfn[MAX_NR_ZONES] __initdata;
370 static unsigned long arch_zone_highest_possible_pfn[MAX_NR_ZONES] __initdata;
371 static unsigned long required_kernelcore __initdata;
372 static unsigned long required_kernelcore_percent __initdata;
373 static unsigned long required_movablecore __initdata;
374 static unsigned long required_movablecore_percent __initdata;
375 static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
376 static bool mirrored_kernelcore __meminitdata;
378 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
380 EXPORT_SYMBOL(movable_zone);
383 unsigned int nr_node_ids __read_mostly = MAX_NUMNODES;
384 unsigned int nr_online_nodes __read_mostly = 1;
385 EXPORT_SYMBOL(nr_node_ids);
386 EXPORT_SYMBOL(nr_online_nodes);
389 int page_group_by_mobility_disabled __read_mostly;
391 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
393 * During boot we initialize deferred pages on-demand, as needed, but once
394 * page_alloc_init_late() has finished, the deferred pages are all initialized,
395 * and we can permanently disable that path.
397 static DEFINE_STATIC_KEY_TRUE(deferred_pages);
400 * Calling kasan_free_pages() only after deferred memory initialization
401 * has completed. Poisoning pages during deferred memory init will greatly
402 * lengthen the process and cause problem in large memory systems as the
403 * deferred pages initialization is done with interrupt disabled.
405 * Assuming that there will be no reference to those newly initialized
406 * pages before they are ever allocated, this should have no effect on
407 * KASAN memory tracking as the poison will be properly inserted at page
408 * allocation time. The only corner case is when pages are allocated by
409 * on-demand allocation and then freed again before the deferred pages
410 * initialization is done, but this is not likely to happen.
412 static inline void kasan_free_nondeferred_pages(struct page *page, int order)
414 if (!static_branch_unlikely(&deferred_pages))
415 kasan_free_pages(page, order);
418 /* Returns true if the struct page for the pfn is uninitialised */
419 static inline bool __meminit early_page_uninitialised(unsigned long pfn)
421 int nid = early_pfn_to_nid(pfn);
423 if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn)
430 * Returns true when the remaining initialisation should be deferred until
431 * later in the boot cycle when it can be parallelised.
433 static bool __meminit
434 defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
436 static unsigned long prev_end_pfn, nr_initialised;
439 * prev_end_pfn static that contains the end of previous zone
440 * No need to protect because called very early in boot before smp_init.
442 if (prev_end_pfn != end_pfn) {
443 prev_end_pfn = end_pfn;
447 /* Always populate low zones for address-constrained allocations */
448 if (end_pfn < pgdat_end_pfn(NODE_DATA(nid)))
451 if (NODE_DATA(nid)->first_deferred_pfn != ULONG_MAX)
454 * We start only with one section of pages, more pages are added as
455 * needed until the rest of deferred pages are initialized.
458 if ((nr_initialised > PAGES_PER_SECTION) &&
459 (pfn & (PAGES_PER_SECTION - 1)) == 0) {
460 NODE_DATA(nid)->first_deferred_pfn = pfn;
466 #define kasan_free_nondeferred_pages(p, o) kasan_free_pages(p, o)
468 static inline bool early_page_uninitialised(unsigned long pfn)
473 static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
479 /* Return a pointer to the bitmap storing bits affecting a block of pages */
480 static inline unsigned long *get_pageblock_bitmap(struct page *page,
483 #ifdef CONFIG_SPARSEMEM
484 return section_to_usemap(__pfn_to_section(pfn));
486 return page_zone(page)->pageblock_flags;
487 #endif /* CONFIG_SPARSEMEM */
490 static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
492 #ifdef CONFIG_SPARSEMEM
493 pfn &= (PAGES_PER_SECTION-1);
495 pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
496 #endif /* CONFIG_SPARSEMEM */
497 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
501 * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
502 * @page: The page within the block of interest
503 * @pfn: The target page frame number
504 * @mask: mask of bits that the caller is interested in
506 * Return: pageblock_bits flags
508 static __always_inline
509 unsigned long __get_pfnblock_flags_mask(struct page *page,
513 unsigned long *bitmap;
514 unsigned long bitidx, word_bitidx;
517 bitmap = get_pageblock_bitmap(page, pfn);
518 bitidx = pfn_to_bitidx(page, pfn);
519 word_bitidx = bitidx / BITS_PER_LONG;
520 bitidx &= (BITS_PER_LONG-1);
522 word = bitmap[word_bitidx];
523 return (word >> bitidx) & mask;
526 unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
529 return __get_pfnblock_flags_mask(page, pfn, mask);
532 static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
534 return __get_pfnblock_flags_mask(page, pfn, MIGRATETYPE_MASK);
538 * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
539 * @page: The page within the block of interest
540 * @flags: The flags to set
541 * @pfn: The target page frame number
542 * @mask: mask of bits that the caller is interested in
544 void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
548 unsigned long *bitmap;
549 unsigned long bitidx, word_bitidx;
550 unsigned long old_word, word;
552 BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
553 BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits));
555 bitmap = get_pageblock_bitmap(page, pfn);
556 bitidx = pfn_to_bitidx(page, pfn);
557 word_bitidx = bitidx / BITS_PER_LONG;
558 bitidx &= (BITS_PER_LONG-1);
560 VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
565 word = READ_ONCE(bitmap[word_bitidx]);
567 old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags);
568 if (word == old_word)
574 void set_pageblock_migratetype(struct page *page, int migratetype)
576 if (unlikely(page_group_by_mobility_disabled &&
577 migratetype < MIGRATE_PCPTYPES))
578 migratetype = MIGRATE_UNMOVABLE;
580 set_pfnblock_flags_mask(page, (unsigned long)migratetype,
581 page_to_pfn(page), MIGRATETYPE_MASK);
584 #ifdef CONFIG_DEBUG_VM
585 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
589 unsigned long pfn = page_to_pfn(page);
590 unsigned long sp, start_pfn;
593 seq = zone_span_seqbegin(zone);
594 start_pfn = zone->zone_start_pfn;
595 sp = zone->spanned_pages;
596 if (!zone_spans_pfn(zone, pfn))
598 } while (zone_span_seqretry(zone, seq));
601 pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
602 pfn, zone_to_nid(zone), zone->name,
603 start_pfn, start_pfn + sp);
608 static int page_is_consistent(struct zone *zone, struct page *page)
610 if (!pfn_valid_within(page_to_pfn(page)))
612 if (zone != page_zone(page))
618 * Temporary debugging check for pages not lying within a given zone.
620 static int __maybe_unused bad_range(struct zone *zone, struct page *page)
622 if (page_outside_zone_boundaries(zone, page))
624 if (!page_is_consistent(zone, page))
630 static inline int __maybe_unused bad_range(struct zone *zone, struct page *page)
636 static void bad_page(struct page *page, const char *reason)
638 static unsigned long resume;
639 static unsigned long nr_shown;
640 static unsigned long nr_unshown;
643 * Allow a burst of 60 reports, then keep quiet for that minute;
644 * or allow a steady drip of one report per second.
646 if (nr_shown == 60) {
647 if (time_before(jiffies, resume)) {
653 "BUG: Bad page state: %lu messages suppressed\n",
660 resume = jiffies + 60 * HZ;
662 pr_alert("BUG: Bad page state in process %s pfn:%05lx\n",
663 current->comm, page_to_pfn(page));
664 __dump_page(page, reason);
665 dump_page_owner(page);
670 /* Leave bad fields for debug, except PageBuddy could make trouble */
671 page_mapcount_reset(page); /* remove PageBuddy */
672 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
676 * Higher-order pages are called "compound pages". They are structured thusly:
678 * The first PAGE_SIZE page is called the "head page" and have PG_head set.
680 * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded
681 * in bit 0 of page->compound_head. The rest of bits is pointer to head page.
683 * The first tail page's ->compound_dtor holds the offset in array of compound
684 * page destructors. See compound_page_dtors.
686 * The first tail page's ->compound_order holds the order of allocation.
687 * This usage means that zero-order pages may not be compound.
690 void free_compound_page(struct page *page)
692 mem_cgroup_uncharge(page);
693 __free_pages_ok(page, compound_order(page), FPI_NONE);
696 void prep_compound_page(struct page *page, unsigned int order)
699 int nr_pages = 1 << order;
702 for (i = 1; i < nr_pages; i++) {
703 struct page *p = page + i;
704 set_page_count(p, 0);
705 p->mapping = TAIL_MAPPING;
706 set_compound_head(p, page);
709 set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
710 set_compound_order(page, order);
711 atomic_set(compound_mapcount_ptr(page), -1);
712 if (hpage_pincount_available(page))
713 atomic_set(compound_pincount_ptr(page), 0);
716 #ifdef CONFIG_DEBUG_PAGEALLOC
717 unsigned int _debug_guardpage_minorder;
719 bool _debug_pagealloc_enabled_early __read_mostly
720 = IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
721 EXPORT_SYMBOL(_debug_pagealloc_enabled_early);
722 DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
723 EXPORT_SYMBOL(_debug_pagealloc_enabled);
725 DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
727 static int __init early_debug_pagealloc(char *buf)
729 return kstrtobool(buf, &_debug_pagealloc_enabled_early);
731 early_param("debug_pagealloc", early_debug_pagealloc);
733 void init_debug_pagealloc(void)
735 if (!debug_pagealloc_enabled())
738 static_branch_enable(&_debug_pagealloc_enabled);
740 if (!debug_guardpage_minorder())
743 static_branch_enable(&_debug_guardpage_enabled);
746 static int __init debug_guardpage_minorder_setup(char *buf)
750 if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) {
751 pr_err("Bad debug_guardpage_minorder value\n");
754 _debug_guardpage_minorder = res;
755 pr_info("Setting debug_guardpage_minorder to %lu\n", res);
758 early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
760 static inline bool set_page_guard(struct zone *zone, struct page *page,
761 unsigned int order, int migratetype)
763 if (!debug_guardpage_enabled())
766 if (order >= debug_guardpage_minorder())
769 __SetPageGuard(page);
770 INIT_LIST_HEAD(&page->lru);
771 set_page_private(page, order);
772 /* Guard pages are not available for any usage */
773 __mod_zone_freepage_state(zone, -(1 << order), migratetype);
778 static inline void clear_page_guard(struct zone *zone, struct page *page,
779 unsigned int order, int migratetype)
781 if (!debug_guardpage_enabled())
784 __ClearPageGuard(page);
786 set_page_private(page, 0);
787 if (!is_migrate_isolate(migratetype))
788 __mod_zone_freepage_state(zone, (1 << order), migratetype);
791 static inline bool set_page_guard(struct zone *zone, struct page *page,
792 unsigned int order, int migratetype) { return false; }
793 static inline void clear_page_guard(struct zone *zone, struct page *page,
794 unsigned int order, int migratetype) {}
797 static inline void set_buddy_order(struct page *page, unsigned int order)
799 set_page_private(page, order);
800 __SetPageBuddy(page);
804 * This function checks whether a page is free && is the buddy
805 * we can coalesce a page and its buddy if
806 * (a) the buddy is not in a hole (check before calling!) &&
807 * (b) the buddy is in the buddy system &&
808 * (c) a page and its buddy have the same order &&
809 * (d) a page and its buddy are in the same zone.
811 * For recording whether a page is in the buddy system, we set PageBuddy.
812 * Setting, clearing, and testing PageBuddy is serialized by zone->lock.
814 * For recording page's order, we use page_private(page).
816 static inline bool page_is_buddy(struct page *page, struct page *buddy,
819 if (!page_is_guard(buddy) && !PageBuddy(buddy))
822 if (buddy_order(buddy) != order)
826 * zone check is done late to avoid uselessly calculating
827 * zone/node ids for pages that could never merge.
829 if (page_zone_id(page) != page_zone_id(buddy))
832 VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
837 #ifdef CONFIG_COMPACTION
838 static inline struct capture_control *task_capc(struct zone *zone)
840 struct capture_control *capc = current->capture_control;
842 return unlikely(capc) &&
843 !(current->flags & PF_KTHREAD) &&
845 capc->cc->zone == zone ? capc : NULL;
849 compaction_capture(struct capture_control *capc, struct page *page,
850 int order, int migratetype)
852 if (!capc || order != capc->cc->order)
855 /* Do not accidentally pollute CMA or isolated regions*/
856 if (is_migrate_cma(migratetype) ||
857 is_migrate_isolate(migratetype))
861 * Do not let lower order allocations polluate a movable pageblock.
862 * This might let an unmovable request use a reclaimable pageblock
863 * and vice-versa but no more than normal fallback logic which can
864 * have trouble finding a high-order free page.
866 if (order < pageblock_order && migratetype == MIGRATE_MOVABLE)
874 static inline struct capture_control *task_capc(struct zone *zone)
880 compaction_capture(struct capture_control *capc, struct page *page,
881 int order, int migratetype)
885 #endif /* CONFIG_COMPACTION */
887 /* Used for pages not on another list */
888 static inline void add_to_free_list(struct page *page, struct zone *zone,
889 unsigned int order, int migratetype)
891 struct free_area *area = &zone->free_area[order];
893 list_add(&page->lru, &area->free_list[migratetype]);
897 /* Used for pages not on another list */
898 static inline void add_to_free_list_tail(struct page *page, struct zone *zone,
899 unsigned int order, int migratetype)
901 struct free_area *area = &zone->free_area[order];
903 list_add_tail(&page->lru, &area->free_list[migratetype]);
908 * Used for pages which are on another list. Move the pages to the tail
909 * of the list - so the moved pages won't immediately be considered for
910 * allocation again (e.g., optimization for memory onlining).
912 static inline void move_to_free_list(struct page *page, struct zone *zone,
913 unsigned int order, int migratetype)
915 struct free_area *area = &zone->free_area[order];
917 list_move_tail(&page->lru, &area->free_list[migratetype]);
920 static inline void del_page_from_free_list(struct page *page, struct zone *zone,
923 /* clear reported state and update reported page count */
924 if (page_reported(page))
925 __ClearPageReported(page);
927 list_del(&page->lru);
928 __ClearPageBuddy(page);
929 set_page_private(page, 0);
930 zone->free_area[order].nr_free--;
934 * If this is not the largest possible page, check if the buddy
935 * of the next-highest order is free. If it is, it's possible
936 * that pages are being freed that will coalesce soon. In case,
937 * that is happening, add the free page to the tail of the list
938 * so it's less likely to be used soon and more likely to be merged
939 * as a higher order page
942 buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn,
943 struct page *page, unsigned int order)
945 struct page *higher_page, *higher_buddy;
946 unsigned long combined_pfn;
948 if (order >= MAX_ORDER - 2)
951 if (!pfn_valid_within(buddy_pfn))
954 combined_pfn = buddy_pfn & pfn;
955 higher_page = page + (combined_pfn - pfn);
956 buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1);
957 higher_buddy = higher_page + (buddy_pfn - combined_pfn);
959 return pfn_valid_within(buddy_pfn) &&
960 page_is_buddy(higher_page, higher_buddy, order + 1);
964 * Freeing function for a buddy system allocator.
966 * The concept of a buddy system is to maintain direct-mapped table
967 * (containing bit values) for memory blocks of various "orders".
968 * The bottom level table contains the map for the smallest allocatable
969 * units of memory (here, pages), and each level above it describes
970 * pairs of units from the levels below, hence, "buddies".
971 * At a high level, all that happens here is marking the table entry
972 * at the bottom level available, and propagating the changes upward
973 * as necessary, plus some accounting needed to play nicely with other
974 * parts of the VM system.
975 * At each level, we keep a list of pages, which are heads of continuous
976 * free pages of length of (1 << order) and marked with PageBuddy.
977 * Page's order is recorded in page_private(page) field.
978 * So when we are allocating or freeing one, we can derive the state of the
979 * other. That is, if we allocate a small block, and both were
980 * free, the remainder of the region must be split into blocks.
981 * If a block is freed, and its buddy is also free, then this
982 * triggers coalescing into a block of larger size.
987 static inline void __free_one_page(struct page *page,
989 struct zone *zone, unsigned int order,
990 int migratetype, fpi_t fpi_flags)
992 struct capture_control *capc = task_capc(zone);
993 unsigned long buddy_pfn;
994 unsigned long combined_pfn;
995 unsigned int max_order;
999 max_order = min_t(unsigned int, MAX_ORDER - 1, pageblock_order);
1001 VM_BUG_ON(!zone_is_initialized(zone));
1002 VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
1004 VM_BUG_ON(migratetype == -1);
1005 if (likely(!is_migrate_isolate(migratetype)))
1006 __mod_zone_freepage_state(zone, 1 << order, migratetype);
1008 VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
1009 VM_BUG_ON_PAGE(bad_range(zone, page), page);
1012 while (order < max_order) {
1013 if (compaction_capture(capc, page, order, migratetype)) {
1014 __mod_zone_freepage_state(zone, -(1 << order),
1018 buddy_pfn = __find_buddy_pfn(pfn, order);
1019 buddy = page + (buddy_pfn - pfn);
1021 if (!pfn_valid_within(buddy_pfn))
1023 if (!page_is_buddy(page, buddy, order))
1026 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
1027 * merge with it and move up one order.
1029 if (page_is_guard(buddy))
1030 clear_page_guard(zone, buddy, order, migratetype);
1032 del_page_from_free_list(buddy, zone, order);
1033 combined_pfn = buddy_pfn & pfn;
1034 page = page + (combined_pfn - pfn);
1038 if (order < MAX_ORDER - 1) {
1039 /* If we are here, it means order is >= pageblock_order.
1040 * We want to prevent merge between freepages on isolate
1041 * pageblock and normal pageblock. Without this, pageblock
1042 * isolation could cause incorrect freepage or CMA accounting.
1044 * We don't want to hit this code for the more frequent
1045 * low-order merging.
1047 if (unlikely(has_isolate_pageblock(zone))) {
1050 buddy_pfn = __find_buddy_pfn(pfn, order);
1051 buddy = page + (buddy_pfn - pfn);
1052 buddy_mt = get_pageblock_migratetype(buddy);
1054 if (migratetype != buddy_mt
1055 && (is_migrate_isolate(migratetype) ||
1056 is_migrate_isolate(buddy_mt)))
1059 max_order = order + 1;
1060 goto continue_merging;
1064 set_buddy_order(page, order);
1066 if (fpi_flags & FPI_TO_TAIL)
1068 else if (is_shuffle_order(order))
1069 to_tail = shuffle_pick_tail();
1071 to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order);
1074 add_to_free_list_tail(page, zone, order, migratetype);
1076 add_to_free_list(page, zone, order, migratetype);
1078 /* Notify page reporting subsystem of freed page */
1079 if (!(fpi_flags & FPI_SKIP_REPORT_NOTIFY))
1080 page_reporting_notify_free(order);
1084 * A bad page could be due to a number of fields. Instead of multiple branches,
1085 * try and check multiple fields with one check. The caller must do a detailed
1086 * check if necessary.
1088 static inline bool page_expected_state(struct page *page,
1089 unsigned long check_flags)
1091 if (unlikely(atomic_read(&page->_mapcount) != -1))
1094 if (unlikely((unsigned long)page->mapping |
1095 page_ref_count(page) |
1097 (unsigned long)page->mem_cgroup |
1099 (page->flags & check_flags)))
1105 static const char *page_bad_reason(struct page *page, unsigned long flags)
1107 const char *bad_reason = NULL;
1109 if (unlikely(atomic_read(&page->_mapcount) != -1))
1110 bad_reason = "nonzero mapcount";
1111 if (unlikely(page->mapping != NULL))
1112 bad_reason = "non-NULL mapping";
1113 if (unlikely(page_ref_count(page) != 0))
1114 bad_reason = "nonzero _refcount";
1115 if (unlikely(page->flags & flags)) {
1116 if (flags == PAGE_FLAGS_CHECK_AT_PREP)
1117 bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag(s) set";
1119 bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
1122 if (unlikely(page->mem_cgroup))
1123 bad_reason = "page still charged to cgroup";
1128 static void check_free_page_bad(struct page *page)
1131 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_FREE));
1134 static inline int check_free_page(struct page *page)
1136 if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE)))
1139 /* Something has gone sideways, find it */
1140 check_free_page_bad(page);
1144 static int free_tail_pages_check(struct page *head_page, struct page *page)
1149 * We rely page->lru.next never has bit 0 set, unless the page
1150 * is PageTail(). Let's make sure that's true even for poisoned ->lru.
1152 BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1);
1154 if (!IS_ENABLED(CONFIG_DEBUG_VM)) {
1158 switch (page - head_page) {
1160 /* the first tail page: ->mapping may be compound_mapcount() */
1161 if (unlikely(compound_mapcount(page))) {
1162 bad_page(page, "nonzero compound_mapcount");
1168 * the second tail page: ->mapping is
1169 * deferred_list.next -- ignore value.
1173 if (page->mapping != TAIL_MAPPING) {
1174 bad_page(page, "corrupted mapping in tail page");
1179 if (unlikely(!PageTail(page))) {
1180 bad_page(page, "PageTail not set");
1183 if (unlikely(compound_head(page) != head_page)) {
1184 bad_page(page, "compound_head not consistent");
1189 page->mapping = NULL;
1190 clear_compound_head(page);
1194 static void kernel_init_free_pages(struct page *page, int numpages)
1198 /* s390's use of memset() could override KASAN redzones. */
1199 kasan_disable_current();
1200 for (i = 0; i < numpages; i++)
1201 clear_highpage(page + i);
1202 kasan_enable_current();
1205 static __always_inline bool free_pages_prepare(struct page *page,
1206 unsigned int order, bool check_free)
1210 VM_BUG_ON_PAGE(PageTail(page), page);
1212 trace_mm_page_free(page, order);
1214 if (unlikely(PageHWPoison(page)) && !order) {
1216 * Do not let hwpoison pages hit pcplists/buddy
1217 * Untie memcg state and reset page's owner
1219 if (memcg_kmem_enabled() && PageKmemcg(page))
1220 __memcg_kmem_uncharge_page(page, order);
1221 reset_page_owner(page, order);
1226 * Check tail pages before head page information is cleared to
1227 * avoid checking PageCompound for order-0 pages.
1229 if (unlikely(order)) {
1230 bool compound = PageCompound(page);
1233 VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
1236 ClearPageDoubleMap(page);
1237 for (i = 1; i < (1 << order); i++) {
1239 bad += free_tail_pages_check(page, page + i);
1240 if (unlikely(check_free_page(page + i))) {
1244 (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1247 if (PageMappingFlags(page))
1248 page->mapping = NULL;
1249 if (memcg_kmem_enabled() && PageKmemcg(page))
1250 __memcg_kmem_uncharge_page(page, order);
1252 bad += check_free_page(page);
1256 page_cpupid_reset_last(page);
1257 page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1258 reset_page_owner(page, order);
1260 if (!PageHighMem(page)) {
1261 debug_check_no_locks_freed(page_address(page),
1262 PAGE_SIZE << order);
1263 debug_check_no_obj_freed(page_address(page),
1264 PAGE_SIZE << order);
1266 if (want_init_on_free())
1267 kernel_init_free_pages(page, 1 << order);
1269 kernel_poison_pages(page, 1 << order, 0);
1271 * arch_free_page() can make the page's contents inaccessible. s390
1272 * does this. So nothing which can access the page's contents should
1273 * happen after this.
1275 arch_free_page(page, order);
1277 if (debug_pagealloc_enabled_static())
1278 kernel_map_pages(page, 1 << order, 0);
1280 kasan_free_nondeferred_pages(page, order);
1285 #ifdef CONFIG_DEBUG_VM
1287 * With DEBUG_VM enabled, order-0 pages are checked immediately when being freed
1288 * to pcp lists. With debug_pagealloc also enabled, they are also rechecked when
1289 * moved from pcp lists to free lists.
1291 static bool free_pcp_prepare(struct page *page)
1293 return free_pages_prepare(page, 0, true);
1296 static bool bulkfree_pcp_prepare(struct page *page)
1298 if (debug_pagealloc_enabled_static())
1299 return check_free_page(page);
1305 * With DEBUG_VM disabled, order-0 pages being freed are checked only when
1306 * moving from pcp lists to free list in order to reduce overhead. With
1307 * debug_pagealloc enabled, they are checked also immediately when being freed
1310 static bool free_pcp_prepare(struct page *page)
1312 if (debug_pagealloc_enabled_static())
1313 return free_pages_prepare(page, 0, true);
1315 return free_pages_prepare(page, 0, false);
1318 static bool bulkfree_pcp_prepare(struct page *page)
1320 return check_free_page(page);
1322 #endif /* CONFIG_DEBUG_VM */
1324 static inline void prefetch_buddy(struct page *page)
1326 unsigned long pfn = page_to_pfn(page);
1327 unsigned long buddy_pfn = __find_buddy_pfn(pfn, 0);
1328 struct page *buddy = page + (buddy_pfn - pfn);
1334 * Frees a number of pages from the PCP lists
1335 * Assumes all pages on list are in same zone, and of same order.
1336 * count is the number of pages to free.
1338 * If the zone was previously in an "all pages pinned" state then look to
1339 * see if this freeing clears that state.
1341 * And clear the zone's pages_scanned counter, to hold off the "all pages are
1342 * pinned" detection logic.
1344 static void free_pcppages_bulk(struct zone *zone, int count,
1345 struct per_cpu_pages *pcp)
1347 int migratetype = 0;
1349 int prefetch_nr = 0;
1350 bool isolated_pageblocks;
1351 struct page *page, *tmp;
1355 * Ensure proper count is passed which otherwise would stuck in the
1356 * below while (list_empty(list)) loop.
1358 count = min(pcp->count, count);
1360 struct list_head *list;
1363 * Remove pages from lists in a round-robin fashion. A
1364 * batch_free count is maintained that is incremented when an
1365 * empty list is encountered. This is so more pages are freed
1366 * off fuller lists instead of spinning excessively around empty
1371 if (++migratetype == MIGRATE_PCPTYPES)
1373 list = &pcp->lists[migratetype];
1374 } while (list_empty(list));
1376 /* This is the only non-empty list. Free them all. */
1377 if (batch_free == MIGRATE_PCPTYPES)
1381 page = list_last_entry(list, struct page, lru);
1382 /* must delete to avoid corrupting pcp list */
1383 list_del(&page->lru);
1386 if (bulkfree_pcp_prepare(page))
1389 list_add_tail(&page->lru, &head);
1392 * We are going to put the page back to the global
1393 * pool, prefetch its buddy to speed up later access
1394 * under zone->lock. It is believed the overhead of
1395 * an additional test and calculating buddy_pfn here
1396 * can be offset by reduced memory latency later. To
1397 * avoid excessive prefetching due to large count, only
1398 * prefetch buddy for the first pcp->batch nr of pages.
1400 if (prefetch_nr++ < pcp->batch)
1401 prefetch_buddy(page);
1402 } while (--count && --batch_free && !list_empty(list));
1405 spin_lock(&zone->lock);
1406 isolated_pageblocks = has_isolate_pageblock(zone);
1409 * Use safe version since after __free_one_page(),
1410 * page->lru.next will not point to original list.
1412 list_for_each_entry_safe(page, tmp, &head, lru) {
1413 int mt = get_pcppage_migratetype(page);
1414 /* MIGRATE_ISOLATE page should not go to pcplists */
1415 VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
1416 /* Pageblock could have been isolated meanwhile */
1417 if (unlikely(isolated_pageblocks))
1418 mt = get_pageblock_migratetype(page);
1420 __free_one_page(page, page_to_pfn(page), zone, 0, mt, FPI_NONE);
1421 trace_mm_page_pcpu_drain(page, 0, mt);
1423 spin_unlock(&zone->lock);
1426 static void free_one_page(struct zone *zone,
1427 struct page *page, unsigned long pfn,
1429 int migratetype, fpi_t fpi_flags)
1431 spin_lock(&zone->lock);
1432 if (unlikely(has_isolate_pageblock(zone) ||
1433 is_migrate_isolate(migratetype))) {
1434 migratetype = get_pfnblock_migratetype(page, pfn);
1436 __free_one_page(page, pfn, zone, order, migratetype, fpi_flags);
1437 spin_unlock(&zone->lock);
1440 static void __meminit __init_single_page(struct page *page, unsigned long pfn,
1441 unsigned long zone, int nid)
1443 mm_zero_struct_page(page);
1444 set_page_links(page, zone, nid, pfn);
1445 init_page_count(page);
1446 page_mapcount_reset(page);
1447 page_cpupid_reset_last(page);
1448 page_kasan_tag_reset(page);
1450 INIT_LIST_HEAD(&page->lru);
1451 #ifdef WANT_PAGE_VIRTUAL
1452 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
1453 if (!is_highmem_idx(zone))
1454 set_page_address(page, __va(pfn << PAGE_SHIFT));
1458 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1459 static void __meminit init_reserved_page(unsigned long pfn)
1464 if (!early_page_uninitialised(pfn))
1467 nid = early_pfn_to_nid(pfn);
1468 pgdat = NODE_DATA(nid);
1470 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1471 struct zone *zone = &pgdat->node_zones[zid];
1473 if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
1476 __init_single_page(pfn_to_page(pfn), pfn, zid, nid);
1479 static inline void init_reserved_page(unsigned long pfn)
1482 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1485 * Initialised pages do not have PageReserved set. This function is
1486 * called for each range allocated by the bootmem allocator and
1487 * marks the pages PageReserved. The remaining valid pages are later
1488 * sent to the buddy page allocator.
1490 void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
1492 unsigned long start_pfn = PFN_DOWN(start);
1493 unsigned long end_pfn = PFN_UP(end);
1495 for (; start_pfn < end_pfn; start_pfn++) {
1496 if (pfn_valid(start_pfn)) {
1497 struct page *page = pfn_to_page(start_pfn);
1499 init_reserved_page(start_pfn);
1501 /* Avoid false-positive PageTail() */
1502 INIT_LIST_HEAD(&page->lru);
1505 * no need for atomic set_bit because the struct
1506 * page is not visible yet so nobody should
1509 __SetPageReserved(page);
1514 static void __free_pages_ok(struct page *page, unsigned int order,
1517 unsigned long flags;
1519 unsigned long pfn = page_to_pfn(page);
1521 if (!free_pages_prepare(page, order, true))
1524 migratetype = get_pfnblock_migratetype(page, pfn);
1525 local_irq_save(flags);
1526 __count_vm_events(PGFREE, 1 << order);
1527 free_one_page(page_zone(page), page, pfn, order, migratetype,
1529 local_irq_restore(flags);
1532 void __free_pages_core(struct page *page, unsigned int order)
1534 unsigned int nr_pages = 1 << order;
1535 struct page *p = page;
1539 * When initializing the memmap, __init_single_page() sets the refcount
1540 * of all pages to 1 ("allocated"/"not free"). We have to set the
1541 * refcount of all involved pages to 0.
1544 for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
1546 __ClearPageReserved(p);
1547 set_page_count(p, 0);
1549 __ClearPageReserved(p);
1550 set_page_count(p, 0);
1552 atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
1555 * Bypass PCP and place fresh pages right to the tail, primarily
1556 * relevant for memory onlining.
1558 __free_pages_ok(page, order, FPI_TO_TAIL);
1561 #ifdef CONFIG_NEED_MULTIPLE_NODES
1563 static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
1565 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
1568 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
1570 int __meminit __early_pfn_to_nid(unsigned long pfn,
1571 struct mminit_pfnnid_cache *state)
1573 unsigned long start_pfn, end_pfn;
1576 if (state->last_start <= pfn && pfn < state->last_end)
1577 return state->last_nid;
1579 nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
1580 if (nid != NUMA_NO_NODE) {
1581 state->last_start = start_pfn;
1582 state->last_end = end_pfn;
1583 state->last_nid = nid;
1588 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
1590 int __meminit early_pfn_to_nid(unsigned long pfn)
1592 static DEFINE_SPINLOCK(early_pfn_lock);
1595 spin_lock(&early_pfn_lock);
1596 nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
1598 nid = first_online_node;
1599 spin_unlock(&early_pfn_lock);
1603 #endif /* CONFIG_NEED_MULTIPLE_NODES */
1605 void __init memblock_free_pages(struct page *page, unsigned long pfn,
1608 if (early_page_uninitialised(pfn))
1610 __free_pages_core(page, order);
1614 * Check that the whole (or subset of) a pageblock given by the interval of
1615 * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
1616 * with the migration of free compaction scanner. The scanners then need to
1617 * use only pfn_valid_within() check for arches that allow holes within
1620 * Return struct page pointer of start_pfn, or NULL if checks were not passed.
1622 * It's possible on some configurations to have a setup like node0 node1 node0
1623 * i.e. it's possible that all pages within a zones range of pages do not
1624 * belong to a single zone. We assume that a border between node0 and node1
1625 * can occur within a single pageblock, but not a node0 node1 node0
1626 * interleaving within a single pageblock. It is therefore sufficient to check
1627 * the first and last page of a pageblock and avoid checking each individual
1628 * page in a pageblock.
1630 struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
1631 unsigned long end_pfn, struct zone *zone)
1633 struct page *start_page;
1634 struct page *end_page;
1636 /* end_pfn is one past the range we are checking */
1639 if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
1642 start_page = pfn_to_online_page(start_pfn);
1646 if (page_zone(start_page) != zone)
1649 end_page = pfn_to_page(end_pfn);
1651 /* This gives a shorter code than deriving page_zone(end_page) */
1652 if (page_zone_id(start_page) != page_zone_id(end_page))
1658 void set_zone_contiguous(struct zone *zone)
1660 unsigned long block_start_pfn = zone->zone_start_pfn;
1661 unsigned long block_end_pfn;
1663 block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages);
1664 for (; block_start_pfn < zone_end_pfn(zone);
1665 block_start_pfn = block_end_pfn,
1666 block_end_pfn += pageblock_nr_pages) {
1668 block_end_pfn = min(block_end_pfn, zone_end_pfn(zone));
1670 if (!__pageblock_pfn_to_page(block_start_pfn,
1671 block_end_pfn, zone))
1676 /* We confirm that there is no hole */
1677 zone->contiguous = true;
1680 void clear_zone_contiguous(struct zone *zone)
1682 zone->contiguous = false;
1685 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1686 static void __init deferred_free_range(unsigned long pfn,
1687 unsigned long nr_pages)
1695 page = pfn_to_page(pfn);
1697 /* Free a large naturally-aligned chunk if possible */
1698 if (nr_pages == pageblock_nr_pages &&
1699 (pfn & (pageblock_nr_pages - 1)) == 0) {
1700 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1701 __free_pages_core(page, pageblock_order);
1705 for (i = 0; i < nr_pages; i++, page++, pfn++) {
1706 if ((pfn & (pageblock_nr_pages - 1)) == 0)
1707 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1708 __free_pages_core(page, 0);
1712 /* Completion tracking for deferred_init_memmap() threads */
1713 static atomic_t pgdat_init_n_undone __initdata;
1714 static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp);
1716 static inline void __init pgdat_init_report_one_done(void)
1718 if (atomic_dec_and_test(&pgdat_init_n_undone))
1719 complete(&pgdat_init_all_done_comp);
1723 * Returns true if page needs to be initialized or freed to buddy allocator.
1725 * First we check if pfn is valid on architectures where it is possible to have
1726 * holes within pageblock_nr_pages. On systems where it is not possible, this
1727 * function is optimized out.
1729 * Then, we check if a current large page is valid by only checking the validity
1732 static inline bool __init deferred_pfn_valid(unsigned long pfn)
1734 if (!pfn_valid_within(pfn))
1736 if (!(pfn & (pageblock_nr_pages - 1)) && !pfn_valid(pfn))
1742 * Free pages to buddy allocator. Try to free aligned pages in
1743 * pageblock_nr_pages sizes.
1745 static void __init deferred_free_pages(unsigned long pfn,
1746 unsigned long end_pfn)
1748 unsigned long nr_pgmask = pageblock_nr_pages - 1;
1749 unsigned long nr_free = 0;
1751 for (; pfn < end_pfn; pfn++) {
1752 if (!deferred_pfn_valid(pfn)) {
1753 deferred_free_range(pfn - nr_free, nr_free);
1755 } else if (!(pfn & nr_pgmask)) {
1756 deferred_free_range(pfn - nr_free, nr_free);
1762 /* Free the last block of pages to allocator */
1763 deferred_free_range(pfn - nr_free, nr_free);
1767 * Initialize struct pages. We minimize pfn page lookups and scheduler checks
1768 * by performing it only once every pageblock_nr_pages.
1769 * Return number of pages initialized.
1771 static unsigned long __init deferred_init_pages(struct zone *zone,
1773 unsigned long end_pfn)
1775 unsigned long nr_pgmask = pageblock_nr_pages - 1;
1776 int nid = zone_to_nid(zone);
1777 unsigned long nr_pages = 0;
1778 int zid = zone_idx(zone);
1779 struct page *page = NULL;
1781 for (; pfn < end_pfn; pfn++) {
1782 if (!deferred_pfn_valid(pfn)) {
1785 } else if (!page || !(pfn & nr_pgmask)) {
1786 page = pfn_to_page(pfn);
1790 __init_single_page(page, pfn, zid, nid);
1797 * This function is meant to pre-load the iterator for the zone init.
1798 * Specifically it walks through the ranges until we are caught up to the
1799 * first_init_pfn value and exits there. If we never encounter the value we
1800 * return false indicating there are no valid ranges left.
1803 deferred_init_mem_pfn_range_in_zone(u64 *i, struct zone *zone,
1804 unsigned long *spfn, unsigned long *epfn,
1805 unsigned long first_init_pfn)
1810 * Start out by walking through the ranges in this zone that have
1811 * already been initialized. We don't need to do anything with them
1812 * so we just need to flush them out of the system.
1814 for_each_free_mem_pfn_range_in_zone(j, zone, spfn, epfn) {
1815 if (*epfn <= first_init_pfn)
1817 if (*spfn < first_init_pfn)
1818 *spfn = first_init_pfn;
1827 * Initialize and free pages. We do it in two loops: first we initialize
1828 * struct page, then free to buddy allocator, because while we are
1829 * freeing pages we can access pages that are ahead (computing buddy
1830 * page in __free_one_page()).
1832 * In order to try and keep some memory in the cache we have the loop
1833 * broken along max page order boundaries. This way we will not cause
1834 * any issues with the buddy page computation.
1836 static unsigned long __init
1837 deferred_init_maxorder(u64 *i, struct zone *zone, unsigned long *start_pfn,
1838 unsigned long *end_pfn)
1840 unsigned long mo_pfn = ALIGN(*start_pfn + 1, MAX_ORDER_NR_PAGES);
1841 unsigned long spfn = *start_pfn, epfn = *end_pfn;
1842 unsigned long nr_pages = 0;
1845 /* First we loop through and initialize the page values */
1846 for_each_free_mem_pfn_range_in_zone_from(j, zone, start_pfn, end_pfn) {
1849 if (mo_pfn <= *start_pfn)
1852 t = min(mo_pfn, *end_pfn);
1853 nr_pages += deferred_init_pages(zone, *start_pfn, t);
1855 if (mo_pfn < *end_pfn) {
1856 *start_pfn = mo_pfn;
1861 /* Reset values and now loop through freeing pages as needed */
1864 for_each_free_mem_pfn_range_in_zone_from(j, zone, &spfn, &epfn) {
1870 t = min(mo_pfn, epfn);
1871 deferred_free_pages(spfn, t);
1881 deferred_init_memmap_chunk(unsigned long start_pfn, unsigned long end_pfn,
1884 unsigned long spfn, epfn;
1885 struct zone *zone = arg;
1888 deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, start_pfn);
1891 * Initialize and free pages in MAX_ORDER sized increments so that we
1892 * can avoid introducing any issues with the buddy allocator.
1894 while (spfn < end_pfn) {
1895 deferred_init_maxorder(&i, zone, &spfn, &epfn);
1900 /* An arch may override for more concurrency. */
1902 deferred_page_init_max_threads(const struct cpumask *node_cpumask)
1907 /* Initialise remaining memory on a node */
1908 static int __init deferred_init_memmap(void *data)
1910 pg_data_t *pgdat = data;
1911 const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
1912 unsigned long spfn = 0, epfn = 0;
1913 unsigned long first_init_pfn, flags;
1914 unsigned long start = jiffies;
1916 int zid, max_threads;
1919 /* Bind memory initialisation thread to a local node if possible */
1920 if (!cpumask_empty(cpumask))
1921 set_cpus_allowed_ptr(current, cpumask);
1923 pgdat_resize_lock(pgdat, &flags);
1924 first_init_pfn = pgdat->first_deferred_pfn;
1925 if (first_init_pfn == ULONG_MAX) {
1926 pgdat_resize_unlock(pgdat, &flags);
1927 pgdat_init_report_one_done();
1931 /* Sanity check boundaries */
1932 BUG_ON(pgdat->first_deferred_pfn < pgdat->node_start_pfn);
1933 BUG_ON(pgdat->first_deferred_pfn > pgdat_end_pfn(pgdat));
1934 pgdat->first_deferred_pfn = ULONG_MAX;
1937 * Once we unlock here, the zone cannot be grown anymore, thus if an
1938 * interrupt thread must allocate this early in boot, zone must be
1939 * pre-grown prior to start of deferred page initialization.
1941 pgdat_resize_unlock(pgdat, &flags);
1943 /* Only the highest zone is deferred so find it */
1944 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1945 zone = pgdat->node_zones + zid;
1946 if (first_init_pfn < zone_end_pfn(zone))
1950 /* If the zone is empty somebody else may have cleared out the zone */
1951 if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
1955 max_threads = deferred_page_init_max_threads(cpumask);
1957 while (spfn < epfn) {
1958 unsigned long epfn_align = ALIGN(epfn, PAGES_PER_SECTION);
1959 struct padata_mt_job job = {
1960 .thread_fn = deferred_init_memmap_chunk,
1963 .size = epfn_align - spfn,
1964 .align = PAGES_PER_SECTION,
1965 .min_chunk = PAGES_PER_SECTION,
1966 .max_threads = max_threads,
1969 padata_do_multithreaded(&job);
1970 deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
1974 /* Sanity check that the next zone really is unpopulated */
1975 WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));
1977 pr_info("node %d deferred pages initialised in %ums\n",
1978 pgdat->node_id, jiffies_to_msecs(jiffies - start));
1980 pgdat_init_report_one_done();
1985 * If this zone has deferred pages, try to grow it by initializing enough
1986 * deferred pages to satisfy the allocation specified by order, rounded up to
1987 * the nearest PAGES_PER_SECTION boundary. So we're adding memory in increments
1988 * of SECTION_SIZE bytes by initializing struct pages in increments of
1989 * PAGES_PER_SECTION * sizeof(struct page) bytes.
1991 * Return true when zone was grown, otherwise return false. We return true even
1992 * when we grow less than requested, to let the caller decide if there are
1993 * enough pages to satisfy the allocation.
1995 * Note: We use noinline because this function is needed only during boot, and
1996 * it is called from a __ref function _deferred_grow_zone. This way we are
1997 * making sure that it is not inlined into permanent text section.
1999 static noinline bool __init
2000 deferred_grow_zone(struct zone *zone, unsigned int order)
2002 unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION);
2003 pg_data_t *pgdat = zone->zone_pgdat;
2004 unsigned long first_deferred_pfn = pgdat->first_deferred_pfn;
2005 unsigned long spfn, epfn, flags;
2006 unsigned long nr_pages = 0;
2009 /* Only the last zone may have deferred pages */
2010 if (zone_end_pfn(zone) != pgdat_end_pfn(pgdat))
2013 pgdat_resize_lock(pgdat, &flags);
2016 * If someone grew this zone while we were waiting for spinlock, return
2017 * true, as there might be enough pages already.
2019 if (first_deferred_pfn != pgdat->first_deferred_pfn) {
2020 pgdat_resize_unlock(pgdat, &flags);
2024 /* If the zone is empty somebody else may have cleared out the zone */
2025 if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
2026 first_deferred_pfn)) {
2027 pgdat->first_deferred_pfn = ULONG_MAX;
2028 pgdat_resize_unlock(pgdat, &flags);
2029 /* Retry only once. */
2030 return first_deferred_pfn != ULONG_MAX;
2034 * Initialize and free pages in MAX_ORDER sized increments so
2035 * that we can avoid introducing any issues with the buddy
2038 while (spfn < epfn) {
2039 /* update our first deferred PFN for this section */
2040 first_deferred_pfn = spfn;
2042 nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
2043 touch_nmi_watchdog();
2045 /* We should only stop along section boundaries */
2046 if ((first_deferred_pfn ^ spfn) < PAGES_PER_SECTION)
2049 /* If our quota has been met we can stop here */
2050 if (nr_pages >= nr_pages_needed)
2054 pgdat->first_deferred_pfn = spfn;
2055 pgdat_resize_unlock(pgdat, &flags);
2057 return nr_pages > 0;
2061 * deferred_grow_zone() is __init, but it is called from
2062 * get_page_from_freelist() during early boot until deferred_pages permanently
2063 * disables this call. This is why we have refdata wrapper to avoid warning,
2064 * and to ensure that the function body gets unloaded.
2067 _deferred_grow_zone(struct zone *zone, unsigned int order)
2069 return deferred_grow_zone(zone, order);
2072 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
2074 void __init page_alloc_init_late(void)
2079 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
2081 /* There will be num_node_state(N_MEMORY) threads */
2082 atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY));
2083 for_each_node_state(nid, N_MEMORY) {
2084 kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid);
2087 /* Block until all are initialised */
2088 wait_for_completion(&pgdat_init_all_done_comp);
2091 * The number of managed pages has changed due to the initialisation
2092 * so the pcpu batch and high limits needs to be updated or the limits
2093 * will be artificially small.
2095 for_each_populated_zone(zone)
2096 zone_pcp_update(zone);
2099 * We initialized the rest of the deferred pages. Permanently disable
2100 * on-demand struct page initialization.
2102 static_branch_disable(&deferred_pages);
2104 /* Reinit limits that are based on free pages after the kernel is up */
2105 files_maxfiles_init();
2108 /* Discard memblock private memory */
2111 for_each_node_state(nid, N_MEMORY)
2112 shuffle_free_memory(NODE_DATA(nid));
2114 for_each_populated_zone(zone)
2115 set_zone_contiguous(zone);
2119 /* Free whole pageblock and set its migration type to MIGRATE_CMA. */
2120 void __init init_cma_reserved_pageblock(struct page *page)
2122 unsigned i = pageblock_nr_pages;
2123 struct page *p = page;
2126 __ClearPageReserved(p);
2127 set_page_count(p, 0);
2130 set_pageblock_migratetype(page, MIGRATE_CMA);
2132 if (pageblock_order >= MAX_ORDER) {
2133 i = pageblock_nr_pages;
2136 set_page_refcounted(p);
2137 __free_pages(p, MAX_ORDER - 1);
2138 p += MAX_ORDER_NR_PAGES;
2139 } while (i -= MAX_ORDER_NR_PAGES);
2141 set_page_refcounted(page);
2142 __free_pages(page, pageblock_order);
2145 adjust_managed_page_count(page, pageblock_nr_pages);
2150 * The order of subdivision here is critical for the IO subsystem.
2151 * Please do not alter this order without good reasons and regression
2152 * testing. Specifically, as large blocks of memory are subdivided,
2153 * the order in which smaller blocks are delivered depends on the order
2154 * they're subdivided in this function. This is the primary factor
2155 * influencing the order in which pages are delivered to the IO
2156 * subsystem according to empirical testing, and this is also justified
2157 * by considering the behavior of a buddy system containing a single
2158 * large block of memory acted on by a series of small allocations.
2159 * This behavior is a critical factor in sglist merging's success.
2163 static inline void expand(struct zone *zone, struct page *page,
2164 int low, int high, int migratetype)
2166 unsigned long size = 1 << high;
2168 while (high > low) {
2171 VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
2174 * Mark as guard pages (or page), that will allow to
2175 * merge back to allocator when buddy will be freed.
2176 * Corresponding page table entries will not be touched,
2177 * pages will stay not present in virtual address space
2179 if (set_page_guard(zone, &page[size], high, migratetype))
2182 add_to_free_list(&page[size], zone, high, migratetype);
2183 set_buddy_order(&page[size], high);
2187 static void check_new_page_bad(struct page *page)
2189 if (unlikely(page->flags & __PG_HWPOISON)) {
2190 /* Don't complain about hwpoisoned pages */
2191 page_mapcount_reset(page); /* remove PageBuddy */
2196 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP));
2200 * This page is about to be returned from the page allocator
2202 static inline int check_new_page(struct page *page)
2204 if (likely(page_expected_state(page,
2205 PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON)))
2208 check_new_page_bad(page);
2212 static inline bool free_pages_prezeroed(void)
2214 return (IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) &&
2215 page_poisoning_enabled()) || want_init_on_free();
2218 #ifdef CONFIG_DEBUG_VM
2220 * With DEBUG_VM enabled, order-0 pages are checked for expected state when
2221 * being allocated from pcp lists. With debug_pagealloc also enabled, they are
2222 * also checked when pcp lists are refilled from the free lists.
2224 static inline bool check_pcp_refill(struct page *page)
2226 if (debug_pagealloc_enabled_static())
2227 return check_new_page(page);
2232 static inline bool check_new_pcp(struct page *page)
2234 return check_new_page(page);
2238 * With DEBUG_VM disabled, free order-0 pages are checked for expected state
2239 * when pcp lists are being refilled from the free lists. With debug_pagealloc
2240 * enabled, they are also checked when being allocated from the pcp lists.
2242 static inline bool check_pcp_refill(struct page *page)
2244 return check_new_page(page);
2246 static inline bool check_new_pcp(struct page *page)
2248 if (debug_pagealloc_enabled_static())
2249 return check_new_page(page);
2253 #endif /* CONFIG_DEBUG_VM */
2255 static bool check_new_pages(struct page *page, unsigned int order)
2258 for (i = 0; i < (1 << order); i++) {
2259 struct page *p = page + i;
2261 if (unlikely(check_new_page(p)))
2268 inline void post_alloc_hook(struct page *page, unsigned int order,
2271 set_page_private(page, 0);
2272 set_page_refcounted(page);
2274 arch_alloc_page(page, order);
2275 if (debug_pagealloc_enabled_static())
2276 kernel_map_pages(page, 1 << order, 1);
2277 kasan_alloc_pages(page, order);
2278 kernel_poison_pages(page, 1 << order, 1);
2279 set_page_owner(page, order, gfp_flags);
2282 static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
2283 unsigned int alloc_flags)
2285 post_alloc_hook(page, order, gfp_flags);
2287 if (!free_pages_prezeroed() && want_init_on_alloc(gfp_flags))
2288 kernel_init_free_pages(page, 1 << order);
2290 if (order && (gfp_flags & __GFP_COMP))
2291 prep_compound_page(page, order);
2294 * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
2295 * allocate the page. The expectation is that the caller is taking
2296 * steps that will free more memory. The caller should avoid the page
2297 * being used for !PFMEMALLOC purposes.
2299 if (alloc_flags & ALLOC_NO_WATERMARKS)
2300 set_page_pfmemalloc(page);
2302 clear_page_pfmemalloc(page);
2306 * Go through the free lists for the given migratetype and remove
2307 * the smallest available page from the freelists
2309 static __always_inline
2310 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
2313 unsigned int current_order;
2314 struct free_area *area;
2317 /* Find a page of the appropriate size in the preferred list */
2318 for (current_order = order; current_order < MAX_ORDER; ++current_order) {
2319 area = &(zone->free_area[current_order]);
2320 page = get_page_from_free_area(area, migratetype);
2323 del_page_from_free_list(page, zone, current_order);
2324 expand(zone, page, order, current_order, migratetype);
2325 set_pcppage_migratetype(page, migratetype);
2334 * This array describes the order lists are fallen back to when
2335 * the free lists for the desirable migrate type are depleted
2337 static int fallbacks[MIGRATE_TYPES][3] = {
2338 [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
2339 [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
2340 [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
2342 [MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */
2344 #ifdef CONFIG_MEMORY_ISOLATION
2345 [MIGRATE_ISOLATE] = { MIGRATE_TYPES }, /* Never used */
2350 static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone,
2353 return __rmqueue_smallest(zone, order, MIGRATE_CMA);
2356 static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
2357 unsigned int order) { return NULL; }
2361 * Move the free pages in a range to the freelist tail of the requested type.
2362 * Note that start_page and end_pages are not aligned on a pageblock
2363 * boundary. If alignment is required, use move_freepages_block()
2365 static int move_freepages(struct zone *zone,
2366 struct page *start_page, struct page *end_page,
2367 int migratetype, int *num_movable)
2371 int pages_moved = 0;
2373 for (page = start_page; page <= end_page;) {
2374 if (!pfn_valid_within(page_to_pfn(page))) {
2379 if (!PageBuddy(page)) {
2381 * We assume that pages that could be isolated for
2382 * migration are movable. But we don't actually try
2383 * isolating, as that would be expensive.
2386 (PageLRU(page) || __PageMovable(page)))
2393 /* Make sure we are not inadvertently changing nodes */
2394 VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
2395 VM_BUG_ON_PAGE(page_zone(page) != zone, page);
2397 order = buddy_order(page);
2398 move_to_free_list(page, zone, order, migratetype);
2400 pages_moved += 1 << order;
2406 int move_freepages_block(struct zone *zone, struct page *page,
2407 int migratetype, int *num_movable)
2409 unsigned long start_pfn, end_pfn;
2410 struct page *start_page, *end_page;
2415 start_pfn = page_to_pfn(page);
2416 start_pfn = start_pfn & ~(pageblock_nr_pages-1);
2417 start_page = pfn_to_page(start_pfn);
2418 end_page = start_page + pageblock_nr_pages - 1;
2419 end_pfn = start_pfn + pageblock_nr_pages - 1;
2421 /* Do not cross zone boundaries */
2422 if (!zone_spans_pfn(zone, start_pfn))
2424 if (!zone_spans_pfn(zone, end_pfn))
2427 return move_freepages(zone, start_page, end_page, migratetype,
2431 static void change_pageblock_range(struct page *pageblock_page,
2432 int start_order, int migratetype)
2434 int nr_pageblocks = 1 << (start_order - pageblock_order);
2436 while (nr_pageblocks--) {
2437 set_pageblock_migratetype(pageblock_page, migratetype);
2438 pageblock_page += pageblock_nr_pages;
2443 * When we are falling back to another migratetype during allocation, try to
2444 * steal extra free pages from the same pageblocks to satisfy further
2445 * allocations, instead of polluting multiple pageblocks.
2447 * If we are stealing a relatively large buddy page, it is likely there will
2448 * be more free pages in the pageblock, so try to steal them all. For
2449 * reclaimable and unmovable allocations, we steal regardless of page size,
2450 * as fragmentation caused by those allocations polluting movable pageblocks
2451 * is worse than movable allocations stealing from unmovable and reclaimable
2454 static bool can_steal_fallback(unsigned int order, int start_mt)
2457 * Leaving this order check is intended, although there is
2458 * relaxed order check in next check. The reason is that
2459 * we can actually steal whole pageblock if this condition met,
2460 * but, below check doesn't guarantee it and that is just heuristic
2461 * so could be changed anytime.
2463 if (order >= pageblock_order)
2466 if (order >= pageblock_order / 2 ||
2467 start_mt == MIGRATE_RECLAIMABLE ||
2468 start_mt == MIGRATE_UNMOVABLE ||
2469 page_group_by_mobility_disabled)
2475 static inline bool boost_watermark(struct zone *zone)
2477 unsigned long max_boost;
2479 if (!watermark_boost_factor)
2482 * Don't bother in zones that are unlikely to produce results.
2483 * On small machines, including kdump capture kernels running
2484 * in a small area, boosting the watermark can cause an out of
2485 * memory situation immediately.
2487 if ((pageblock_nr_pages * 4) > zone_managed_pages(zone))
2490 max_boost = mult_frac(zone->_watermark[WMARK_HIGH],
2491 watermark_boost_factor, 10000);
2494 * high watermark may be uninitialised if fragmentation occurs
2495 * very early in boot so do not boost. We do not fall
2496 * through and boost by pageblock_nr_pages as failing
2497 * allocations that early means that reclaim is not going
2498 * to help and it may even be impossible to reclaim the
2499 * boosted watermark resulting in a hang.
2504 max_boost = max(pageblock_nr_pages, max_boost);
2506 zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages,
2513 * This function implements actual steal behaviour. If order is large enough,
2514 * we can steal whole pageblock. If not, we first move freepages in this
2515 * pageblock to our migratetype and determine how many already-allocated pages
2516 * are there in the pageblock with a compatible migratetype. If at least half
2517 * of pages are free or compatible, we can change migratetype of the pageblock
2518 * itself, so pages freed in the future will be put on the correct free list.
2520 static void steal_suitable_fallback(struct zone *zone, struct page *page,
2521 unsigned int alloc_flags, int start_type, bool whole_block)
2523 unsigned int current_order = buddy_order(page);
2524 int free_pages, movable_pages, alike_pages;
2527 old_block_type = get_pageblock_migratetype(page);
2530 * This can happen due to races and we want to prevent broken
2531 * highatomic accounting.
2533 if (is_migrate_highatomic(old_block_type))
2536 /* Take ownership for orders >= pageblock_order */
2537 if (current_order >= pageblock_order) {
2538 change_pageblock_range(page, current_order, start_type);
2543 * Boost watermarks to increase reclaim pressure to reduce the
2544 * likelihood of future fallbacks. Wake kswapd now as the node
2545 * may be balanced overall and kswapd will not wake naturally.
2547 if (boost_watermark(zone) && (alloc_flags & ALLOC_KSWAPD))
2548 set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
2550 /* We are not allowed to try stealing from the whole block */
2554 free_pages = move_freepages_block(zone, page, start_type,
2557 * Determine how many pages are compatible with our allocation.
2558 * For movable allocation, it's the number of movable pages which
2559 * we just obtained. For other types it's a bit more tricky.
2561 if (start_type == MIGRATE_MOVABLE) {
2562 alike_pages = movable_pages;
2565 * If we are falling back a RECLAIMABLE or UNMOVABLE allocation
2566 * to MOVABLE pageblock, consider all non-movable pages as
2567 * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or
2568 * vice versa, be conservative since we can't distinguish the
2569 * exact migratetype of non-movable pages.
2571 if (old_block_type == MIGRATE_MOVABLE)
2572 alike_pages = pageblock_nr_pages
2573 - (free_pages + movable_pages);
2578 /* moving whole block can fail due to zone boundary conditions */
2583 * If a sufficient number of pages in the block are either free or of
2584 * comparable migratability as our allocation, claim the whole block.
2586 if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||
2587 page_group_by_mobility_disabled)
2588 set_pageblock_migratetype(page, start_type);
2593 move_to_free_list(page, zone, current_order, start_type);
2597 * Check whether there is a suitable fallback freepage with requested order.
2598 * If only_stealable is true, this function returns fallback_mt only if
2599 * we can steal other freepages all together. This would help to reduce
2600 * fragmentation due to mixed migratetype pages in one pageblock.
2602 int find_suitable_fallback(struct free_area *area, unsigned int order,
2603 int migratetype, bool only_stealable, bool *can_steal)
2608 if (area->nr_free == 0)
2613 fallback_mt = fallbacks[migratetype][i];
2614 if (fallback_mt == MIGRATE_TYPES)
2617 if (free_area_empty(area, fallback_mt))
2620 if (can_steal_fallback(order, migratetype))
2623 if (!only_stealable)
2634 * Reserve a pageblock for exclusive use of high-order atomic allocations if
2635 * there are no empty page blocks that contain a page with a suitable order
2637 static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
2638 unsigned int alloc_order)
2641 unsigned long max_managed, flags;
2644 * Limit the number reserved to 1 pageblock or roughly 1% of a zone.
2645 * Check is race-prone but harmless.
2647 max_managed = (zone_managed_pages(zone) / 100) + pageblock_nr_pages;
2648 if (zone->nr_reserved_highatomic >= max_managed)
2651 spin_lock_irqsave(&zone->lock, flags);
2653 /* Recheck the nr_reserved_highatomic limit under the lock */
2654 if (zone->nr_reserved_highatomic >= max_managed)
2658 mt = get_pageblock_migratetype(page);
2659 if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt)
2660 && !is_migrate_cma(mt)) {
2661 zone->nr_reserved_highatomic += pageblock_nr_pages;
2662 set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
2663 move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL);
2667 spin_unlock_irqrestore(&zone->lock, flags);
2671 * Used when an allocation is about to fail under memory pressure. This
2672 * potentially hurts the reliability of high-order allocations when under
2673 * intense memory pressure but failed atomic allocations should be easier
2674 * to recover from than an OOM.
2676 * If @force is true, try to unreserve a pageblock even though highatomic
2677 * pageblock is exhausted.
2679 static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
2682 struct zonelist *zonelist = ac->zonelist;
2683 unsigned long flags;
2690 for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->highest_zoneidx,
2693 * Preserve at least one pageblock unless memory pressure
2696 if (!force && zone->nr_reserved_highatomic <=
2700 spin_lock_irqsave(&zone->lock, flags);
2701 for (order = 0; order < MAX_ORDER; order++) {
2702 struct free_area *area = &(zone->free_area[order]);
2704 page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
2709 * In page freeing path, migratetype change is racy so
2710 * we can counter several free pages in a pageblock
2711 * in this loop althoug we changed the pageblock type
2712 * from highatomic to ac->migratetype. So we should
2713 * adjust the count once.
2715 if (is_migrate_highatomic_page(page)) {
2717 * It should never happen but changes to
2718 * locking could inadvertently allow a per-cpu
2719 * drain to add pages to MIGRATE_HIGHATOMIC
2720 * while unreserving so be safe and watch for
2723 zone->nr_reserved_highatomic -= min(
2725 zone->nr_reserved_highatomic);
2729 * Convert to ac->migratetype and avoid the normal
2730 * pageblock stealing heuristics. Minimally, the caller
2731 * is doing the work and needs the pages. More
2732 * importantly, if the block was always converted to
2733 * MIGRATE_UNMOVABLE or another type then the number
2734 * of pageblocks that cannot be completely freed
2737 set_pageblock_migratetype(page, ac->migratetype);
2738 ret = move_freepages_block(zone, page, ac->migratetype,
2741 spin_unlock_irqrestore(&zone->lock, flags);
2745 spin_unlock_irqrestore(&zone->lock, flags);
2752 * Try finding a free buddy page on the fallback list and put it on the free
2753 * list of requested migratetype, possibly along with other pages from the same
2754 * block, depending on fragmentation avoidance heuristics. Returns true if
2755 * fallback was found so that __rmqueue_smallest() can grab it.
2757 * The use of signed ints for order and current_order is a deliberate
2758 * deviation from the rest of this file, to make the for loop
2759 * condition simpler.
2761 static __always_inline bool
2762 __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
2763 unsigned int alloc_flags)
2765 struct free_area *area;
2767 int min_order = order;
2773 * Do not steal pages from freelists belonging to other pageblocks
2774 * i.e. orders < pageblock_order. If there are no local zones free,
2775 * the zonelists will be reiterated without ALLOC_NOFRAGMENT.
2777 if (alloc_flags & ALLOC_NOFRAGMENT)
2778 min_order = pageblock_order;
2781 * Find the largest available free page in the other list. This roughly
2782 * approximates finding the pageblock with the most free pages, which
2783 * would be too costly to do exactly.
2785 for (current_order = MAX_ORDER - 1; current_order >= min_order;
2787 area = &(zone->free_area[current_order]);
2788 fallback_mt = find_suitable_fallback(area, current_order,
2789 start_migratetype, false, &can_steal);
2790 if (fallback_mt == -1)
2794 * We cannot steal all free pages from the pageblock and the
2795 * requested migratetype is movable. In that case it's better to
2796 * steal and split the smallest available page instead of the
2797 * largest available page, because even if the next movable
2798 * allocation falls back into a different pageblock than this
2799 * one, it won't cause permanent fragmentation.
2801 if (!can_steal && start_migratetype == MIGRATE_MOVABLE
2802 && current_order > order)
2811 for (current_order = order; current_order < MAX_ORDER;
2813 area = &(zone->free_area[current_order]);
2814 fallback_mt = find_suitable_fallback(area, current_order,
2815 start_migratetype, false, &can_steal);
2816 if (fallback_mt != -1)
2821 * This should not happen - we already found a suitable fallback
2822 * when looking for the largest page.
2824 VM_BUG_ON(current_order == MAX_ORDER);
2827 page = get_page_from_free_area(area, fallback_mt);
2829 steal_suitable_fallback(zone, page, alloc_flags, start_migratetype,
2832 trace_mm_page_alloc_extfrag(page, order, current_order,
2833 start_migratetype, fallback_mt);
2840 * Do the hard work of removing an element from the buddy allocator.
2841 * Call me with the zone->lock already held.
2843 static __always_inline struct page *
2844 __rmqueue(struct zone *zone, unsigned int order, int migratetype,
2845 unsigned int alloc_flags)
2849 if (IS_ENABLED(CONFIG_CMA)) {
2851 * Balance movable allocations between regular and CMA areas by
2852 * allocating from CMA when over half of the zone's free memory
2853 * is in the CMA area.
2855 if (alloc_flags & ALLOC_CMA &&
2856 zone_page_state(zone, NR_FREE_CMA_PAGES) >
2857 zone_page_state(zone, NR_FREE_PAGES) / 2) {
2858 page = __rmqueue_cma_fallback(zone, order);
2864 page = __rmqueue_smallest(zone, order, migratetype);
2865 if (unlikely(!page)) {
2866 if (alloc_flags & ALLOC_CMA)
2867 page = __rmqueue_cma_fallback(zone, order);
2869 if (!page && __rmqueue_fallback(zone, order, migratetype,
2875 trace_mm_page_alloc_zone_locked(page, order, migratetype);
2880 * Obtain a specified number of elements from the buddy allocator, all under
2881 * a single hold of the lock, for efficiency. Add them to the supplied list.
2882 * Returns the number of new pages which were placed at *list.
2884 static int rmqueue_bulk(struct zone *zone, unsigned int order,
2885 unsigned long count, struct list_head *list,
2886 int migratetype, unsigned int alloc_flags)
2890 spin_lock(&zone->lock);
2891 for (i = 0; i < count; ++i) {
2892 struct page *page = __rmqueue(zone, order, migratetype,
2894 if (unlikely(page == NULL))
2897 if (unlikely(check_pcp_refill(page)))
2901 * Split buddy pages returned by expand() are received here in
2902 * physical page order. The page is added to the tail of
2903 * caller's list. From the callers perspective, the linked list
2904 * is ordered by page number under some conditions. This is
2905 * useful for IO devices that can forward direction from the
2906 * head, thus also in the physical page order. This is useful
2907 * for IO devices that can merge IO requests if the physical
2908 * pages are ordered properly.
2910 list_add_tail(&page->lru, list);
2912 if (is_migrate_cma(get_pcppage_migratetype(page)))
2913 __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
2918 * i pages were removed from the buddy list even if some leak due
2919 * to check_pcp_refill failing so adjust NR_FREE_PAGES based
2920 * on i. Do not confuse with 'alloced' which is the number of
2921 * pages added to the pcp list.
2923 __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
2924 spin_unlock(&zone->lock);
2930 * Called from the vmstat counter updater to drain pagesets of this
2931 * currently executing processor on remote nodes after they have
2934 * Note that this function must be called with the thread pinned to
2935 * a single processor.
2937 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
2939 unsigned long flags;
2940 int to_drain, batch;
2942 local_irq_save(flags);
2943 batch = READ_ONCE(pcp->batch);
2944 to_drain = min(pcp->count, batch);
2946 free_pcppages_bulk(zone, to_drain, pcp);
2947 local_irq_restore(flags);
2952 * Drain pcplists of the indicated processor and zone.
2954 * The processor must either be the current processor and the
2955 * thread pinned to the current processor or a processor that
2958 static void drain_pages_zone(unsigned int cpu, struct zone *zone)
2960 unsigned long flags;
2961 struct per_cpu_pageset *pset;
2962 struct per_cpu_pages *pcp;
2964 local_irq_save(flags);
2965 pset = per_cpu_ptr(zone->pageset, cpu);
2969 free_pcppages_bulk(zone, pcp->count, pcp);
2970 local_irq_restore(flags);
2974 * Drain pcplists of all zones on the indicated processor.
2976 * The processor must either be the current processor and the
2977 * thread pinned to the current processor or a processor that
2980 static void drain_pages(unsigned int cpu)
2984 for_each_populated_zone(zone) {
2985 drain_pages_zone(cpu, zone);
2990 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
2992 * The CPU has to be pinned. When zone parameter is non-NULL, spill just
2993 * the single zone's pages.
2995 void drain_local_pages(struct zone *zone)
2997 int cpu = smp_processor_id();
3000 drain_pages_zone(cpu, zone);
3005 static void drain_local_pages_wq(struct work_struct *work)
3007 struct pcpu_drain *drain;
3009 drain = container_of(work, struct pcpu_drain, work);
3012 * drain_all_pages doesn't use proper cpu hotplug protection so
3013 * we can race with cpu offline when the WQ can move this from
3014 * a cpu pinned worker to an unbound one. We can operate on a different
3015 * cpu which is allright but we also have to make sure to not move to
3019 drain_local_pages(drain->zone);
3024 * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
3026 * When zone parameter is non-NULL, spill just the single zone's pages.
3028 * Note that this can be extremely slow as the draining happens in a workqueue.
3030 void drain_all_pages(struct zone *zone)
3035 * Allocate in the BSS so we wont require allocation in
3036 * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
3038 static cpumask_t cpus_with_pcps;
3041 * Make sure nobody triggers this path before mm_percpu_wq is fully
3044 if (WARN_ON_ONCE(!mm_percpu_wq))
3048 * Do not drain if one is already in progress unless it's specific to
3049 * a zone. Such callers are primarily CMA and memory hotplug and need
3050 * the drain to be complete when the call returns.
3052 if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) {
3055 mutex_lock(&pcpu_drain_mutex);
3059 * We don't care about racing with CPU hotplug event
3060 * as offline notification will cause the notified
3061 * cpu to drain that CPU pcps and on_each_cpu_mask
3062 * disables preemption as part of its processing
3064 for_each_online_cpu(cpu) {
3065 struct per_cpu_pageset *pcp;
3067 bool has_pcps = false;
3070 pcp = per_cpu_ptr(zone->pageset, cpu);
3074 for_each_populated_zone(z) {
3075 pcp = per_cpu_ptr(z->pageset, cpu);
3076 if (pcp->pcp.count) {
3084 cpumask_set_cpu(cpu, &cpus_with_pcps);
3086 cpumask_clear_cpu(cpu, &cpus_with_pcps);
3089 for_each_cpu(cpu, &cpus_with_pcps) {
3090 struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu);
3093 INIT_WORK(&drain->work, drain_local_pages_wq);
3094 queue_work_on(cpu, mm_percpu_wq, &drain->work);
3096 for_each_cpu(cpu, &cpus_with_pcps)
3097 flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work);
3099 mutex_unlock(&pcpu_drain_mutex);
3102 #ifdef CONFIG_HIBERNATION
3105 * Touch the watchdog for every WD_PAGE_COUNT pages.
3107 #define WD_PAGE_COUNT (128*1024)
3109 void mark_free_pages(struct zone *zone)
3111 unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
3112 unsigned long flags;
3113 unsigned int order, t;
3116 if (zone_is_empty(zone))
3119 spin_lock_irqsave(&zone->lock, flags);
3121 max_zone_pfn = zone_end_pfn(zone);
3122 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
3123 if (pfn_valid(pfn)) {
3124 page = pfn_to_page(pfn);
3126 if (!--page_count) {
3127 touch_nmi_watchdog();
3128 page_count = WD_PAGE_COUNT;
3131 if (page_zone(page) != zone)
3134 if (!swsusp_page_is_forbidden(page))
3135 swsusp_unset_page_free(page);
3138 for_each_migratetype_order(order, t) {
3139 list_for_each_entry(page,
3140 &zone->free_area[order].free_list[t], lru) {
3143 pfn = page_to_pfn(page);
3144 for (i = 0; i < (1UL << order); i++) {
3145 if (!--page_count) {
3146 touch_nmi_watchdog();
3147 page_count = WD_PAGE_COUNT;
3149 swsusp_set_page_free(pfn_to_page(pfn + i));
3153 spin_unlock_irqrestore(&zone->lock, flags);
3155 #endif /* CONFIG_PM */
3157 static bool free_unref_page_prepare(struct page *page, unsigned long pfn)
3161 if (!free_pcp_prepare(page))
3164 migratetype = get_pfnblock_migratetype(page, pfn);
3165 set_pcppage_migratetype(page, migratetype);
3169 static void free_unref_page_commit(struct page *page, unsigned long pfn)
3171 struct zone *zone = page_zone(page);
3172 struct per_cpu_pages *pcp;
3175 migratetype = get_pcppage_migratetype(page);
3176 __count_vm_event(PGFREE);
3179 * We only track unmovable, reclaimable and movable on pcp lists.
3180 * Free ISOLATE pages back to the allocator because they are being
3181 * offlined but treat HIGHATOMIC as movable pages so we can get those
3182 * areas back if necessary. Otherwise, we may have to free
3183 * excessively into the page allocator
3185 if (migratetype >= MIGRATE_PCPTYPES) {
3186 if (unlikely(is_migrate_isolate(migratetype))) {
3187 free_one_page(zone, page, pfn, 0, migratetype,
3191 migratetype = MIGRATE_MOVABLE;
3194 pcp = &this_cpu_ptr(zone->pageset)->pcp;
3195 list_add(&page->lru, &pcp->lists[migratetype]);
3197 if (pcp->count >= pcp->high) {
3198 unsigned long batch = READ_ONCE(pcp->batch);
3199 free_pcppages_bulk(zone, batch, pcp);
3204 * Free a 0-order page
3206 void free_unref_page(struct page *page)
3208 unsigned long flags;
3209 unsigned long pfn = page_to_pfn(page);
3211 if (!free_unref_page_prepare(page, pfn))
3214 local_irq_save(flags);
3215 free_unref_page_commit(page, pfn);
3216 local_irq_restore(flags);
3220 * Free a list of 0-order pages
3222 void free_unref_page_list(struct list_head *list)
3224 struct page *page, *next;
3225 unsigned long flags, pfn;
3226 int batch_count = 0;
3228 /* Prepare pages for freeing */
3229 list_for_each_entry_safe(page, next, list, lru) {
3230 pfn = page_to_pfn(page);
3231 if (!free_unref_page_prepare(page, pfn))
3232 list_del(&page->lru);
3233 set_page_private(page, pfn);
3236 local_irq_save(flags);
3237 list_for_each_entry_safe(page, next, list, lru) {
3238 unsigned long pfn = page_private(page);
3240 set_page_private(page, 0);
3241 trace_mm_page_free_batched(page);
3242 free_unref_page_commit(page, pfn);
3245 * Guard against excessive IRQ disabled times when we get
3246 * a large list of pages to free.
3248 if (++batch_count == SWAP_CLUSTER_MAX) {
3249 local_irq_restore(flags);
3251 local_irq_save(flags);
3254 local_irq_restore(flags);
3258 * split_page takes a non-compound higher-order page, and splits it into
3259 * n (1<<order) sub-pages: page[0..n]
3260 * Each sub-page must be freed individually.
3262 * Note: this is probably too low level an operation for use in drivers.
3263 * Please consult with lkml before using this in your driver.
3265 void split_page(struct page *page, unsigned int order)
3269 VM_BUG_ON_PAGE(PageCompound(page), page);
3270 VM_BUG_ON_PAGE(!page_count(page), page);
3272 for (i = 1; i < (1 << order); i++)
3273 set_page_refcounted(page + i);
3274 split_page_owner(page, 1 << order);
3275 split_page_memcg(page, 1 << order);
3277 EXPORT_SYMBOL_GPL(split_page);
3279 int __isolate_free_page(struct page *page, unsigned int order)
3281 unsigned long watermark;
3285 BUG_ON(!PageBuddy(page));
3287 zone = page_zone(page);
3288 mt = get_pageblock_migratetype(page);
3290 if (!is_migrate_isolate(mt)) {
3292 * Obey watermarks as if the page was being allocated. We can
3293 * emulate a high-order watermark check with a raised order-0
3294 * watermark, because we already know our high-order page
3297 watermark = zone->_watermark[WMARK_MIN] + (1UL << order);
3298 if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
3301 __mod_zone_freepage_state(zone, -(1UL << order), mt);
3304 /* Remove page from free list */
3306 del_page_from_free_list(page, zone, order);
3309 * Set the pageblock if the isolated page is at least half of a
3312 if (order >= pageblock_order - 1) {
3313 struct page *endpage = page + (1 << order) - 1;
3314 for (; page < endpage; page += pageblock_nr_pages) {
3315 int mt = get_pageblock_migratetype(page);
3316 if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
3317 && !is_migrate_highatomic(mt))
3318 set_pageblock_migratetype(page,
3324 return 1UL << order;
3328 * __putback_isolated_page - Return a now-isolated page back where we got it
3329 * @page: Page that was isolated
3330 * @order: Order of the isolated page
3331 * @mt: The page's pageblock's migratetype
3333 * This function is meant to return a page pulled from the free lists via
3334 * __isolate_free_page back to the free lists they were pulled from.
3336 void __putback_isolated_page(struct page *page, unsigned int order, int mt)
3338 struct zone *zone = page_zone(page);
3340 /* zone lock should be held when this function is called */
3341 lockdep_assert_held(&zone->lock);
3343 /* Return isolated page to tail of freelist. */
3344 __free_one_page(page, page_to_pfn(page), zone, order, mt,
3345 FPI_SKIP_REPORT_NOTIFY | FPI_TO_TAIL);
3349 * Update NUMA hit/miss statistics
3351 * Must be called with interrupts disabled.
3353 static inline void zone_statistics(struct zone *preferred_zone, struct zone *z)
3356 enum numa_stat_item local_stat = NUMA_LOCAL;
3358 /* skip numa counters update if numa stats is disabled */
3359 if (!static_branch_likely(&vm_numa_stat_key))
3362 if (zone_to_nid(z) != numa_node_id())
3363 local_stat = NUMA_OTHER;
3365 if (zone_to_nid(z) == zone_to_nid(preferred_zone))
3366 __inc_numa_state(z, NUMA_HIT);
3368 __inc_numa_state(z, NUMA_MISS);
3369 __inc_numa_state(preferred_zone, NUMA_FOREIGN);
3371 __inc_numa_state(z, local_stat);
3375 /* Remove page from the per-cpu list, caller must protect the list */
3376 static struct page *__rmqueue_pcplist(struct zone *zone, int migratetype,
3377 unsigned int alloc_flags,
3378 struct per_cpu_pages *pcp,
3379 struct list_head *list)
3384 if (list_empty(list)) {
3385 pcp->count += rmqueue_bulk(zone, 0,
3387 migratetype, alloc_flags);
3388 if (unlikely(list_empty(list)))
3392 page = list_first_entry(list, struct page, lru);
3393 list_del(&page->lru);
3395 } while (check_new_pcp(page));
3400 /* Lock and remove page from the per-cpu list */
3401 static struct page *rmqueue_pcplist(struct zone *preferred_zone,
3402 struct zone *zone, gfp_t gfp_flags,
3403 int migratetype, unsigned int alloc_flags)
3405 struct per_cpu_pages *pcp;
3406 struct list_head *list;
3408 unsigned long flags;
3410 local_irq_save(flags);
3411 pcp = &this_cpu_ptr(zone->pageset)->pcp;
3412 list = &pcp->lists[migratetype];
3413 page = __rmqueue_pcplist(zone, migratetype, alloc_flags, pcp, list);
3415 __count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
3416 zone_statistics(preferred_zone, zone);
3418 local_irq_restore(flags);
3423 * Allocate a page from the given zone. Use pcplists for order-0 allocations.
3426 struct page *rmqueue(struct zone *preferred_zone,
3427 struct zone *zone, unsigned int order,
3428 gfp_t gfp_flags, unsigned int alloc_flags,
3431 unsigned long flags;
3434 if (likely(order == 0)) {
3436 * MIGRATE_MOVABLE pcplist could have the pages on CMA area and
3437 * we need to skip it when CMA area isn't allowed.
3439 if (!IS_ENABLED(CONFIG_CMA) || alloc_flags & ALLOC_CMA ||
3440 migratetype != MIGRATE_MOVABLE) {
3441 page = rmqueue_pcplist(preferred_zone, zone, gfp_flags,
3442 migratetype, alloc_flags);
3448 * We most definitely don't want callers attempting to
3449 * allocate greater than order-1 page units with __GFP_NOFAIL.
3451 WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
3452 spin_lock_irqsave(&zone->lock, flags);
3457 * order-0 request can reach here when the pcplist is skipped
3458 * due to non-CMA allocation context. HIGHATOMIC area is
3459 * reserved for high-order atomic allocation, so order-0
3460 * request should skip it.
3462 if (order > 0 && alloc_flags & ALLOC_HARDER) {
3463 page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
3465 trace_mm_page_alloc_zone_locked(page, order, migratetype);
3468 page = __rmqueue(zone, order, migratetype, alloc_flags);
3469 } while (page && check_new_pages(page, order));
3470 spin_unlock(&zone->lock);
3473 __mod_zone_freepage_state(zone, -(1 << order),
3474 get_pcppage_migratetype(page));
3476 __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
3477 zone_statistics(preferred_zone, zone);
3478 local_irq_restore(flags);
3481 /* Separate test+clear to avoid unnecessary atomics */
3482 if (test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags)) {
3483 clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
3484 wakeup_kswapd(zone, 0, 0, zone_idx(zone));
3487 VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
3491 local_irq_restore(flags);
3495 #ifdef CONFIG_FAIL_PAGE_ALLOC
3498 struct fault_attr attr;
3500 bool ignore_gfp_highmem;
3501 bool ignore_gfp_reclaim;
3503 } fail_page_alloc = {
3504 .attr = FAULT_ATTR_INITIALIZER,
3505 .ignore_gfp_reclaim = true,
3506 .ignore_gfp_highmem = true,
3510 static int __init setup_fail_page_alloc(char *str)
3512 return setup_fault_attr(&fail_page_alloc.attr, str);
3514 __setup("fail_page_alloc=", setup_fail_page_alloc);
3516 static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3518 if (order < fail_page_alloc.min_order)
3520 if (gfp_mask & __GFP_NOFAIL)
3522 if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
3524 if (fail_page_alloc.ignore_gfp_reclaim &&
3525 (gfp_mask & __GFP_DIRECT_RECLAIM))
3528 return should_fail(&fail_page_alloc.attr, 1 << order);
3531 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
3533 static int __init fail_page_alloc_debugfs(void)
3535 umode_t mode = S_IFREG | 0600;
3538 dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
3539 &fail_page_alloc.attr);
3541 debugfs_create_bool("ignore-gfp-wait", mode, dir,
3542 &fail_page_alloc.ignore_gfp_reclaim);
3543 debugfs_create_bool("ignore-gfp-highmem", mode, dir,
3544 &fail_page_alloc.ignore_gfp_highmem);
3545 debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);
3550 late_initcall(fail_page_alloc_debugfs);
3552 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
3554 #else /* CONFIG_FAIL_PAGE_ALLOC */
3556 static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3561 #endif /* CONFIG_FAIL_PAGE_ALLOC */
3563 noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3565 return __should_fail_alloc_page(gfp_mask, order);
3567 ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);
3569 static inline long __zone_watermark_unusable_free(struct zone *z,
3570 unsigned int order, unsigned int alloc_flags)
3572 const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM));
3573 long unusable_free = (1 << order) - 1;
3576 * If the caller does not have rights to ALLOC_HARDER then subtract
3577 * the high-atomic reserves. This will over-estimate the size of the
3578 * atomic reserve but it avoids a search.
3580 if (likely(!alloc_harder))
3581 unusable_free += z->nr_reserved_highatomic;
3584 /* If allocation can't use CMA areas don't use free CMA pages */
3585 if (!(alloc_flags & ALLOC_CMA))
3586 unusable_free += zone_page_state(z, NR_FREE_CMA_PAGES);
3589 return unusable_free;
3593 * Return true if free base pages are above 'mark'. For high-order checks it
3594 * will return true of the order-0 watermark is reached and there is at least
3595 * one free page of a suitable size. Checking now avoids taking the zone lock
3596 * to check in the allocation paths if no pages are free.
3598 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
3599 int highest_zoneidx, unsigned int alloc_flags,
3604 const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM));
3606 /* free_pages may go negative - that's OK */
3607 free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags);
3609 if (alloc_flags & ALLOC_HIGH)
3612 if (unlikely(alloc_harder)) {
3614 * OOM victims can try even harder than normal ALLOC_HARDER
3615 * users on the grounds that it's definitely going to be in
3616 * the exit path shortly and free memory. Any allocation it
3617 * makes during the free path will be small and short-lived.
3619 if (alloc_flags & ALLOC_OOM)
3626 * Check watermarks for an order-0 allocation request. If these
3627 * are not met, then a high-order request also cannot go ahead
3628 * even if a suitable page happened to be free.
3630 if (free_pages <= min + z->lowmem_reserve[highest_zoneidx])
3633 /* If this is an order-0 request then the watermark is fine */
3637 /* For a high-order request, check at least one suitable page is free */
3638 for (o = order; o < MAX_ORDER; o++) {
3639 struct free_area *area = &z->free_area[o];
3645 for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
3646 if (!free_area_empty(area, mt))
3651 if ((alloc_flags & ALLOC_CMA) &&
3652 !free_area_empty(area, MIGRATE_CMA)) {
3656 if (alloc_harder && !free_area_empty(area, MIGRATE_HIGHATOMIC))
3662 bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
3663 int highest_zoneidx, unsigned int alloc_flags)
3665 return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags,
3666 zone_page_state(z, NR_FREE_PAGES));
3669 static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
3670 unsigned long mark, int highest_zoneidx,
3671 unsigned int alloc_flags, gfp_t gfp_mask)
3675 free_pages = zone_page_state(z, NR_FREE_PAGES);
3678 * Fast check for order-0 only. If this fails then the reserves
3679 * need to be calculated.
3684 fast_free = free_pages;
3685 fast_free -= __zone_watermark_unusable_free(z, 0, alloc_flags);
3686 if (fast_free > mark + z->lowmem_reserve[highest_zoneidx])
3690 if (__zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags,
3694 * Ignore watermark boosting for GFP_ATOMIC order-0 allocations
3695 * when checking the min watermark. The min watermark is the
3696 * point where boosting is ignored so that kswapd is woken up
3697 * when below the low watermark.
3699 if (unlikely(!order && (gfp_mask & __GFP_ATOMIC) && z->watermark_boost
3700 && ((alloc_flags & ALLOC_WMARK_MASK) == WMARK_MIN))) {
3701 mark = z->_watermark[WMARK_MIN];
3702 return __zone_watermark_ok(z, order, mark, highest_zoneidx,
3703 alloc_flags, free_pages);
3709 bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
3710 unsigned long mark, int highest_zoneidx)
3712 long free_pages = zone_page_state(z, NR_FREE_PAGES);
3714 if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
3715 free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
3717 return __zone_watermark_ok(z, order, mark, highest_zoneidx, 0,
3722 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
3724 return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <=
3725 node_reclaim_distance;
3727 #else /* CONFIG_NUMA */
3728 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
3732 #endif /* CONFIG_NUMA */
3735 * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid
3736 * fragmentation is subtle. If the preferred zone was HIGHMEM then
3737 * premature use of a lower zone may cause lowmem pressure problems that
3738 * are worse than fragmentation. If the next zone is ZONE_DMA then it is
3739 * probably too small. It only makes sense to spread allocations to avoid
3740 * fragmentation between the Normal and DMA32 zones.
3742 static inline unsigned int
3743 alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
3745 unsigned int alloc_flags;
3748 * __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
3751 alloc_flags = (__force int) (gfp_mask & __GFP_KSWAPD_RECLAIM);
3753 #ifdef CONFIG_ZONE_DMA32
3757 if (zone_idx(zone) != ZONE_NORMAL)
3761 * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and
3762 * the pointer is within zone->zone_pgdat->node_zones[]. Also assume
3763 * on UMA that if Normal is populated then so is DMA32.
3765 BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1);
3766 if (nr_online_nodes > 1 && !populated_zone(--zone))
3769 alloc_flags |= ALLOC_NOFRAGMENT;
3770 #endif /* CONFIG_ZONE_DMA32 */
3774 static inline unsigned int current_alloc_flags(gfp_t gfp_mask,
3775 unsigned int alloc_flags)
3778 unsigned int pflags = current->flags;
3780 if (!(pflags & PF_MEMALLOC_NOCMA) &&
3781 gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE)
3782 alloc_flags |= ALLOC_CMA;
3789 * get_page_from_freelist goes through the zonelist trying to allocate
3792 static struct page *
3793 get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
3794 const struct alloc_context *ac)
3798 struct pglist_data *last_pgdat_dirty_limit = NULL;
3803 * Scan zonelist, looking for a zone with enough free.
3804 * See also __cpuset_node_allowed() comment in kernel/cpuset.c.
3806 no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
3807 z = ac->preferred_zoneref;
3808 for_next_zone_zonelist_nodemask(zone, z, ac->highest_zoneidx,
3813 if (cpusets_enabled() &&
3814 (alloc_flags & ALLOC_CPUSET) &&
3815 !__cpuset_zone_allowed(zone, gfp_mask))
3818 * When allocating a page cache page for writing, we
3819 * want to get it from a node that is within its dirty
3820 * limit, such that no single node holds more than its
3821 * proportional share of globally allowed dirty pages.
3822 * The dirty limits take into account the node's
3823 * lowmem reserves and high watermark so that kswapd
3824 * should be able to balance it without having to
3825 * write pages from its LRU list.
3827 * XXX: For now, allow allocations to potentially
3828 * exceed the per-node dirty limit in the slowpath
3829 * (spread_dirty_pages unset) before going into reclaim,
3830 * which is important when on a NUMA setup the allowed
3831 * nodes are together not big enough to reach the
3832 * global limit. The proper fix for these situations
3833 * will require awareness of nodes in the
3834 * dirty-throttling and the flusher threads.
3836 if (ac->spread_dirty_pages) {
3837 if (last_pgdat_dirty_limit == zone->zone_pgdat)
3840 if (!node_dirty_ok(zone->zone_pgdat)) {
3841 last_pgdat_dirty_limit = zone->zone_pgdat;
3846 if (no_fallback && nr_online_nodes > 1 &&
3847 zone != ac->preferred_zoneref->zone) {
3851 * If moving to a remote node, retry but allow
3852 * fragmenting fallbacks. Locality is more important
3853 * than fragmentation avoidance.
3855 local_nid = zone_to_nid(ac->preferred_zoneref->zone);
3856 if (zone_to_nid(zone) != local_nid) {
3857 alloc_flags &= ~ALLOC_NOFRAGMENT;
3862 mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
3863 if (!zone_watermark_fast(zone, order, mark,
3864 ac->highest_zoneidx, alloc_flags,
3868 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
3870 * Watermark failed for this zone, but see if we can
3871 * grow this zone if it contains deferred pages.
3873 if (static_branch_unlikely(&deferred_pages)) {
3874 if (_deferred_grow_zone(zone, order))
3878 /* Checked here to keep the fast path fast */
3879 BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
3880 if (alloc_flags & ALLOC_NO_WATERMARKS)
3883 if (node_reclaim_mode == 0 ||
3884 !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
3887 ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
3889 case NODE_RECLAIM_NOSCAN:
3892 case NODE_RECLAIM_FULL:
3893 /* scanned but unreclaimable */
3896 /* did we reclaim enough */
3897 if (zone_watermark_ok(zone, order, mark,
3898 ac->highest_zoneidx, alloc_flags))
3906 page = rmqueue(ac->preferred_zoneref->zone, zone, order,
3907 gfp_mask, alloc_flags, ac->migratetype);
3909 prep_new_page(page, order, gfp_mask, alloc_flags);
3912 * If this is a high-order atomic allocation then check
3913 * if the pageblock should be reserved for the future
3915 if (unlikely(order && (alloc_flags & ALLOC_HARDER)))
3916 reserve_highatomic_pageblock(page, zone, order);
3920 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
3921 /* Try again if zone has deferred pages */
3922 if (static_branch_unlikely(&deferred_pages)) {
3923 if (_deferred_grow_zone(zone, order))
3931 * It's possible on a UMA machine to get through all zones that are
3932 * fragmented. If avoiding fragmentation, reset and try again.
3935 alloc_flags &= ~ALLOC_NOFRAGMENT;
3942 static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask)
3944 unsigned int filter = SHOW_MEM_FILTER_NODES;
3947 * This documents exceptions given to allocations in certain
3948 * contexts that are allowed to allocate outside current's set
3951 if (!(gfp_mask & __GFP_NOMEMALLOC))
3952 if (tsk_is_oom_victim(current) ||
3953 (current->flags & (PF_MEMALLOC | PF_EXITING)))
3954 filter &= ~SHOW_MEM_FILTER_NODES;
3955 if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
3956 filter &= ~SHOW_MEM_FILTER_NODES;
3958 show_mem(filter, nodemask);
3961 void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)
3963 struct va_format vaf;
3965 static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1);
3967 if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs))
3970 va_start(args, fmt);
3973 pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl",
3974 current->comm, &vaf, gfp_mask, &gfp_mask,
3975 nodemask_pr_args(nodemask));
3978 cpuset_print_current_mems_allowed();
3981 warn_alloc_show_mem(gfp_mask, nodemask);
3984 static inline struct page *
3985 __alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order,
3986 unsigned int alloc_flags,
3987 const struct alloc_context *ac)
3991 page = get_page_from_freelist(gfp_mask, order,
3992 alloc_flags|ALLOC_CPUSET, ac);
3994 * fallback to ignore cpuset restriction if our nodes
3998 page = get_page_from_freelist(gfp_mask, order,
4004 static inline struct page *
4005 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
4006 const struct alloc_context *ac, unsigned long *did_some_progress)
4008 struct oom_control oc = {
4009 .zonelist = ac->zonelist,
4010 .nodemask = ac->nodemask,
4012 .gfp_mask = gfp_mask,
4017 *did_some_progress = 0;
4020 * Acquire the oom lock. If that fails, somebody else is
4021 * making progress for us.
4023 if (!mutex_trylock(&oom_lock)) {
4024 *did_some_progress = 1;
4025 schedule_timeout_uninterruptible(1);
4030 * Go through the zonelist yet one more time, keep very high watermark
4031 * here, this is only to catch a parallel oom killing, we must fail if
4032 * we're still under heavy pressure. But make sure that this reclaim
4033 * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY
4034 * allocation which will never fail due to oom_lock already held.
4036 page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) &
4037 ~__GFP_DIRECT_RECLAIM, order,
4038 ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
4042 /* Coredumps can quickly deplete all memory reserves */
4043 if (current->flags & PF_DUMPCORE)
4045 /* The OOM killer will not help higher order allocs */
4046 if (order > PAGE_ALLOC_COSTLY_ORDER)
4049 * We have already exhausted all our reclaim opportunities without any
4050 * success so it is time to admit defeat. We will skip the OOM killer
4051 * because it is very likely that the caller has a more reasonable
4052 * fallback than shooting a random task.
4054 * The OOM killer may not free memory on a specific node.
4056 if (gfp_mask & (__GFP_RETRY_MAYFAIL | __GFP_THISNODE))
4058 /* The OOM killer does not needlessly kill tasks for lowmem */
4059 if (ac->highest_zoneidx < ZONE_NORMAL)
4061 if (pm_suspended_storage())
4064 * XXX: GFP_NOFS allocations should rather fail than rely on
4065 * other request to make a forward progress.
4066 * We are in an unfortunate situation where out_of_memory cannot
4067 * do much for this context but let's try it to at least get
4068 * access to memory reserved if the current task is killed (see
4069 * out_of_memory). Once filesystems are ready to handle allocation
4070 * failures more gracefully we should just bail out here.
4073 /* Exhausted what can be done so it's blame time */
4074 if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
4075 *did_some_progress = 1;
4078 * Help non-failing allocations by giving them access to memory
4081 if (gfp_mask & __GFP_NOFAIL)
4082 page = __alloc_pages_cpuset_fallback(gfp_mask, order,
4083 ALLOC_NO_WATERMARKS, ac);
4086 mutex_unlock(&oom_lock);
4091 * Maximum number of compaction retries wit a progress before OOM
4092 * killer is consider as the only way to move forward.
4094 #define MAX_COMPACT_RETRIES 16
4096 #ifdef CONFIG_COMPACTION
4097 /* Try memory compaction for high-order allocations before reclaim */
4098 static struct page *
4099 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
4100 unsigned int alloc_flags, const struct alloc_context *ac,
4101 enum compact_priority prio, enum compact_result *compact_result)
4103 struct page *page = NULL;
4104 unsigned long pflags;
4105 unsigned int noreclaim_flag;
4110 psi_memstall_enter(&pflags);
4111 noreclaim_flag = memalloc_noreclaim_save();
4113 *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
4116 memalloc_noreclaim_restore(noreclaim_flag);
4117 psi_memstall_leave(&pflags);
4120 * At least in one zone compaction wasn't deferred or skipped, so let's
4121 * count a compaction stall
4123 count_vm_event(COMPACTSTALL);
4125 /* Prep a captured page if available */
4127 prep_new_page(page, order, gfp_mask, alloc_flags);
4129 /* Try get a page from the freelist if available */
4131 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4134 struct zone *zone = page_zone(page);
4136 zone->compact_blockskip_flush = false;
4137 compaction_defer_reset(zone, order, true);
4138 count_vm_event(COMPACTSUCCESS);
4143 * It's bad if compaction run occurs and fails. The most likely reason
4144 * is that pages exist, but not enough to satisfy watermarks.
4146 count_vm_event(COMPACTFAIL);
4154 should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
4155 enum compact_result compact_result,
4156 enum compact_priority *compact_priority,
4157 int *compaction_retries)
4159 int max_retries = MAX_COMPACT_RETRIES;
4162 int retries = *compaction_retries;
4163 enum compact_priority priority = *compact_priority;
4168 if (compaction_made_progress(compact_result))
4169 (*compaction_retries)++;
4172 * compaction considers all the zone as desperately out of memory
4173 * so it doesn't really make much sense to retry except when the
4174 * failure could be caused by insufficient priority
4176 if (compaction_failed(compact_result))
4177 goto check_priority;
4180 * compaction was skipped because there are not enough order-0 pages
4181 * to work with, so we retry only if it looks like reclaim can help.
4183 if (compaction_needs_reclaim(compact_result)) {
4184 ret = compaction_zonelist_suitable(ac, order, alloc_flags);
4189 * make sure the compaction wasn't deferred or didn't bail out early
4190 * due to locks contention before we declare that we should give up.
4191 * But the next retry should use a higher priority if allowed, so
4192 * we don't just keep bailing out endlessly.
4194 if (compaction_withdrawn(compact_result)) {
4195 goto check_priority;
4199 * !costly requests are much more important than __GFP_RETRY_MAYFAIL
4200 * costly ones because they are de facto nofail and invoke OOM
4201 * killer to move on while costly can fail and users are ready
4202 * to cope with that. 1/4 retries is rather arbitrary but we
4203 * would need much more detailed feedback from compaction to
4204 * make a better decision.
4206 if (order > PAGE_ALLOC_COSTLY_ORDER)
4208 if (*compaction_retries <= max_retries) {
4214 * Make sure there are attempts at the highest priority if we exhausted
4215 * all retries or failed at the lower priorities.
4218 min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ?
4219 MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;
4221 if (*compact_priority > min_priority) {
4222 (*compact_priority)--;
4223 *compaction_retries = 0;
4227 trace_compact_retry(order, priority, compact_result, retries, max_retries, ret);
4231 static inline struct page *
4232 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
4233 unsigned int alloc_flags, const struct alloc_context *ac,
4234 enum compact_priority prio, enum compact_result *compact_result)
4236 *compact_result = COMPACT_SKIPPED;
4241 should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
4242 enum compact_result compact_result,
4243 enum compact_priority *compact_priority,
4244 int *compaction_retries)
4249 if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
4253 * There are setups with compaction disabled which would prefer to loop
4254 * inside the allocator rather than hit the oom killer prematurely.
4255 * Let's give them a good hope and keep retrying while the order-0
4256 * watermarks are OK.
4258 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
4259 ac->highest_zoneidx, ac->nodemask) {
4260 if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
4261 ac->highest_zoneidx, alloc_flags))
4266 #endif /* CONFIG_COMPACTION */
4268 #ifdef CONFIG_LOCKDEP
4269 static struct lockdep_map __fs_reclaim_map =
4270 STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map);
4272 static bool __need_fs_reclaim(gfp_t gfp_mask)
4274 gfp_mask = current_gfp_context(gfp_mask);
4276 /* no reclaim without waiting on it */
4277 if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
4280 /* this guy won't enter reclaim */
4281 if (current->flags & PF_MEMALLOC)
4284 /* We're only interested __GFP_FS allocations for now */
4285 if (!(gfp_mask & __GFP_FS))
4288 if (gfp_mask & __GFP_NOLOCKDEP)
4294 void __fs_reclaim_acquire(void)
4296 lock_map_acquire(&__fs_reclaim_map);
4299 void __fs_reclaim_release(void)
4301 lock_map_release(&__fs_reclaim_map);
4304 void fs_reclaim_acquire(gfp_t gfp_mask)
4306 if (__need_fs_reclaim(gfp_mask))
4307 __fs_reclaim_acquire();
4309 EXPORT_SYMBOL_GPL(fs_reclaim_acquire);
4311 void fs_reclaim_release(gfp_t gfp_mask)
4313 if (__need_fs_reclaim(gfp_mask))
4314 __fs_reclaim_release();
4316 EXPORT_SYMBOL_GPL(fs_reclaim_release);
4319 /* Perform direct synchronous page reclaim */
4320 static unsigned long
4321 __perform_reclaim(gfp_t gfp_mask, unsigned int order,
4322 const struct alloc_context *ac)
4324 unsigned int noreclaim_flag;
4325 unsigned long pflags, progress;
4329 /* We now go into synchronous reclaim */
4330 cpuset_memory_pressure_bump();
4331 psi_memstall_enter(&pflags);
4332 fs_reclaim_acquire(gfp_mask);
4333 noreclaim_flag = memalloc_noreclaim_save();
4335 progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
4338 memalloc_noreclaim_restore(noreclaim_flag);
4339 fs_reclaim_release(gfp_mask);
4340 psi_memstall_leave(&pflags);
4347 /* The really slow allocator path where we enter direct reclaim */
4348 static inline struct page *
4349 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
4350 unsigned int alloc_flags, const struct alloc_context *ac,
4351 unsigned long *did_some_progress)
4353 struct page *page = NULL;
4354 bool drained = false;
4356 *did_some_progress = __perform_reclaim(gfp_mask, order, ac);
4357 if (unlikely(!(*did_some_progress)))
4361 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4364 * If an allocation failed after direct reclaim, it could be because
4365 * pages are pinned on the per-cpu lists or in high alloc reserves.
4366 * Shrink them and try again
4368 if (!page && !drained) {
4369 unreserve_highatomic_pageblock(ac, false);
4370 drain_all_pages(NULL);
4378 static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
4379 const struct alloc_context *ac)
4383 pg_data_t *last_pgdat = NULL;
4384 enum zone_type highest_zoneidx = ac->highest_zoneidx;
4386 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx,
4388 if (last_pgdat != zone->zone_pgdat)
4389 wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx);
4390 last_pgdat = zone->zone_pgdat;
4394 static inline unsigned int
4395 gfp_to_alloc_flags(gfp_t gfp_mask)
4397 unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
4400 * __GFP_HIGH is assumed to be the same as ALLOC_HIGH
4401 * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
4402 * to save two branches.
4404 BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
4405 BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD);
4408 * The caller may dip into page reserves a bit more if the caller
4409 * cannot run direct reclaim, or if the caller has realtime scheduling
4410 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
4411 * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
4413 alloc_flags |= (__force int)
4414 (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM));
4416 if (gfp_mask & __GFP_ATOMIC) {
4418 * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
4419 * if it can't schedule.
4421 if (!(gfp_mask & __GFP_NOMEMALLOC))
4422 alloc_flags |= ALLOC_HARDER;
4424 * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
4425 * comment for __cpuset_node_allowed().
4427 alloc_flags &= ~ALLOC_CPUSET;
4428 } else if (unlikely(rt_task(current)) && !in_interrupt())
4429 alloc_flags |= ALLOC_HARDER;
4431 alloc_flags = current_alloc_flags(gfp_mask, alloc_flags);
4436 static bool oom_reserves_allowed(struct task_struct *tsk)
4438 if (!tsk_is_oom_victim(tsk))
4442 * !MMU doesn't have oom reaper so give access to memory reserves
4443 * only to the thread with TIF_MEMDIE set
4445 if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE))
4452 * Distinguish requests which really need access to full memory
4453 * reserves from oom victims which can live with a portion of it
4455 static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask)
4457 if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
4459 if (gfp_mask & __GFP_MEMALLOC)
4460 return ALLOC_NO_WATERMARKS;
4461 if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
4462 return ALLOC_NO_WATERMARKS;
4463 if (!in_interrupt()) {
4464 if (current->flags & PF_MEMALLOC)
4465 return ALLOC_NO_WATERMARKS;
4466 else if (oom_reserves_allowed(current))
4473 bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
4475 return !!__gfp_pfmemalloc_flags(gfp_mask);
4479 * Checks whether it makes sense to retry the reclaim to make a forward progress
4480 * for the given allocation request.
4482 * We give up when we either have tried MAX_RECLAIM_RETRIES in a row
4483 * without success, or when we couldn't even meet the watermark if we
4484 * reclaimed all remaining pages on the LRU lists.
4486 * Returns true if a retry is viable or false to enter the oom path.
4489 should_reclaim_retry(gfp_t gfp_mask, unsigned order,
4490 struct alloc_context *ac, int alloc_flags,
4491 bool did_some_progress, int *no_progress_loops)
4498 * Costly allocations might have made a progress but this doesn't mean
4499 * their order will become available due to high fragmentation so
4500 * always increment the no progress counter for them
4502 if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
4503 *no_progress_loops = 0;
4505 (*no_progress_loops)++;
4508 * Make sure we converge to OOM if we cannot make any progress
4509 * several times in the row.
4511 if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
4512 /* Before OOM, exhaust highatomic_reserve */
4513 return unreserve_highatomic_pageblock(ac, true);
4517 * Keep reclaiming pages while there is a chance this will lead
4518 * somewhere. If none of the target zones can satisfy our allocation
4519 * request even if all reclaimable pages are considered then we are
4520 * screwed and have to go OOM.
4522 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
4523 ac->highest_zoneidx, ac->nodemask) {
4524 unsigned long available;
4525 unsigned long reclaimable;
4526 unsigned long min_wmark = min_wmark_pages(zone);
4529 available = reclaimable = zone_reclaimable_pages(zone);
4530 available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
4533 * Would the allocation succeed if we reclaimed all
4534 * reclaimable pages?
4536 wmark = __zone_watermark_ok(zone, order, min_wmark,
4537 ac->highest_zoneidx, alloc_flags, available);
4538 trace_reclaim_retry_zone(z, order, reclaimable,
4539 available, min_wmark, *no_progress_loops, wmark);
4542 * If we didn't make any progress and have a lot of
4543 * dirty + writeback pages then we should wait for
4544 * an IO to complete to slow down the reclaim and
4545 * prevent from pre mature OOM
4547 if (!did_some_progress) {
4548 unsigned long write_pending;
4550 write_pending = zone_page_state_snapshot(zone,
4551 NR_ZONE_WRITE_PENDING);
4553 if (2 * write_pending > reclaimable) {
4554 congestion_wait(BLK_RW_ASYNC, HZ/10);
4566 * Memory allocation/reclaim might be called from a WQ context and the
4567 * current implementation of the WQ concurrency control doesn't
4568 * recognize that a particular WQ is congested if the worker thread is
4569 * looping without ever sleeping. Therefore we have to do a short sleep
4570 * here rather than calling cond_resched().
4572 if (current->flags & PF_WQ_WORKER)
4573 schedule_timeout_uninterruptible(1);
4580 check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac)
4583 * It's possible that cpuset's mems_allowed and the nodemask from
4584 * mempolicy don't intersect. This should be normally dealt with by
4585 * policy_nodemask(), but it's possible to race with cpuset update in
4586 * such a way the check therein was true, and then it became false
4587 * before we got our cpuset_mems_cookie here.
4588 * This assumes that for all allocations, ac->nodemask can come only
4589 * from MPOL_BIND mempolicy (whose documented semantics is to be ignored
4590 * when it does not intersect with the cpuset restrictions) or the
4591 * caller can deal with a violated nodemask.
4593 if (cpusets_enabled() && ac->nodemask &&
4594 !cpuset_nodemask_valid_mems_allowed(ac->nodemask)) {
4595 ac->nodemask = NULL;
4600 * When updating a task's mems_allowed or mempolicy nodemask, it is
4601 * possible to race with parallel threads in such a way that our
4602 * allocation can fail while the mask is being updated. If we are about
4603 * to fail, check if the cpuset changed during allocation and if so,
4606 if (read_mems_allowed_retry(cpuset_mems_cookie))
4612 static inline struct page *
4613 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
4614 struct alloc_context *ac)
4616 bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
4617 const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER;
4618 struct page *page = NULL;
4619 unsigned int alloc_flags;
4620 unsigned long did_some_progress;
4621 enum compact_priority compact_priority;
4622 enum compact_result compact_result;
4623 int compaction_retries;
4624 int no_progress_loops;
4625 unsigned int cpuset_mems_cookie;
4629 * We also sanity check to catch abuse of atomic reserves being used by
4630 * callers that are not in atomic context.
4632 if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) ==
4633 (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
4634 gfp_mask &= ~__GFP_ATOMIC;
4637 compaction_retries = 0;
4638 no_progress_loops = 0;
4639 compact_priority = DEF_COMPACT_PRIORITY;
4640 cpuset_mems_cookie = read_mems_allowed_begin();
4643 * The fast path uses conservative alloc_flags to succeed only until
4644 * kswapd needs to be woken up, and to avoid the cost of setting up
4645 * alloc_flags precisely. So we do that now.
4647 alloc_flags = gfp_to_alloc_flags(gfp_mask);
4650 * We need to recalculate the starting point for the zonelist iterator
4651 * because we might have used different nodemask in the fast path, or
4652 * there was a cpuset modification and we are retrying - otherwise we
4653 * could end up iterating over non-eligible zones endlessly.
4655 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4656 ac->highest_zoneidx, ac->nodemask);
4657 if (!ac->preferred_zoneref->zone)
4660 if (alloc_flags & ALLOC_KSWAPD)
4661 wake_all_kswapds(order, gfp_mask, ac);
4664 * The adjusted alloc_flags might result in immediate success, so try
4667 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4672 * For costly allocations, try direct compaction first, as it's likely
4673 * that we have enough base pages and don't need to reclaim. For non-
4674 * movable high-order allocations, do that as well, as compaction will
4675 * try prevent permanent fragmentation by migrating from blocks of the
4677 * Don't try this for allocations that are allowed to ignore
4678 * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen.
4680 if (can_direct_reclaim &&
4682 (order > 0 && ac->migratetype != MIGRATE_MOVABLE))
4683 && !gfp_pfmemalloc_allowed(gfp_mask)) {
4684 page = __alloc_pages_direct_compact(gfp_mask, order,
4686 INIT_COMPACT_PRIORITY,
4692 * Checks for costly allocations with __GFP_NORETRY, which
4693 * includes some THP page fault allocations
4695 if (costly_order && (gfp_mask & __GFP_NORETRY)) {
4697 * If allocating entire pageblock(s) and compaction
4698 * failed because all zones are below low watermarks
4699 * or is prohibited because it recently failed at this
4700 * order, fail immediately unless the allocator has
4701 * requested compaction and reclaim retry.
4704 * - potentially very expensive because zones are far
4705 * below their low watermarks or this is part of very
4706 * bursty high order allocations,
4707 * - not guaranteed to help because isolate_freepages()
4708 * may not iterate over freed pages as part of its
4710 * - unlikely to make entire pageblocks free on its
4713 if (compact_result == COMPACT_SKIPPED ||
4714 compact_result == COMPACT_DEFERRED)
4718 * Looks like reclaim/compaction is worth trying, but
4719 * sync compaction could be very expensive, so keep
4720 * using async compaction.
4722 compact_priority = INIT_COMPACT_PRIORITY;
4727 /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
4728 if (alloc_flags & ALLOC_KSWAPD)
4729 wake_all_kswapds(order, gfp_mask, ac);
4731 reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
4733 alloc_flags = current_alloc_flags(gfp_mask, reserve_flags);
4736 * Reset the nodemask and zonelist iterators if memory policies can be
4737 * ignored. These allocations are high priority and system rather than
4740 if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) {
4741 ac->nodemask = NULL;
4742 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4743 ac->highest_zoneidx, ac->nodemask);
4746 /* Attempt with potentially adjusted zonelist and alloc_flags */
4747 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4751 /* Caller is not willing to reclaim, we can't balance anything */
4752 if (!can_direct_reclaim)
4755 /* Avoid recursion of direct reclaim */
4756 if (current->flags & PF_MEMALLOC)
4759 /* Try direct reclaim and then allocating */
4760 page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
4761 &did_some_progress);
4765 /* Try direct compaction and then allocating */
4766 page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
4767 compact_priority, &compact_result);
4771 /* Do not loop if specifically requested */
4772 if (gfp_mask & __GFP_NORETRY)
4776 * Do not retry costly high order allocations unless they are
4777 * __GFP_RETRY_MAYFAIL
4779 if (costly_order && !(gfp_mask & __GFP_RETRY_MAYFAIL))
4782 if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
4783 did_some_progress > 0, &no_progress_loops))
4787 * It doesn't make any sense to retry for the compaction if the order-0
4788 * reclaim is not able to make any progress because the current
4789 * implementation of the compaction depends on the sufficient amount
4790 * of free memory (see __compaction_suitable)
4792 if (did_some_progress > 0 &&
4793 should_compact_retry(ac, order, alloc_flags,
4794 compact_result, &compact_priority,
4795 &compaction_retries))
4799 /* Deal with possible cpuset update races before we start OOM killing */
4800 if (check_retry_cpuset(cpuset_mems_cookie, ac))
4803 /* Reclaim has failed us, start killing things */
4804 page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
4808 /* Avoid allocations with no watermarks from looping endlessly */
4809 if (tsk_is_oom_victim(current) &&
4810 (alloc_flags & ALLOC_OOM ||
4811 (gfp_mask & __GFP_NOMEMALLOC)))
4814 /* Retry as long as the OOM killer is making progress */
4815 if (did_some_progress) {
4816 no_progress_loops = 0;
4821 /* Deal with possible cpuset update races before we fail */
4822 if (check_retry_cpuset(cpuset_mems_cookie, ac))
4826 * Make sure that __GFP_NOFAIL request doesn't leak out and make sure
4829 if (gfp_mask & __GFP_NOFAIL) {
4831 * All existing users of the __GFP_NOFAIL are blockable, so warn
4832 * of any new users that actually require GFP_NOWAIT
4834 if (WARN_ON_ONCE(!can_direct_reclaim))
4838 * PF_MEMALLOC request from this context is rather bizarre
4839 * because we cannot reclaim anything and only can loop waiting
4840 * for somebody to do a work for us
4842 WARN_ON_ONCE(current->flags & PF_MEMALLOC);
4845 * non failing costly orders are a hard requirement which we
4846 * are not prepared for much so let's warn about these users
4847 * so that we can identify them and convert them to something
4850 WARN_ON_ONCE(order > PAGE_ALLOC_COSTLY_ORDER);
4853 * Help non-failing allocations by giving them access to memory
4854 * reserves but do not use ALLOC_NO_WATERMARKS because this
4855 * could deplete whole memory reserves which would just make
4856 * the situation worse
4858 page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_HARDER, ac);
4866 warn_alloc(gfp_mask, ac->nodemask,
4867 "page allocation failure: order:%u", order);
4872 static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
4873 int preferred_nid, nodemask_t *nodemask,
4874 struct alloc_context *ac, gfp_t *alloc_mask,
4875 unsigned int *alloc_flags)
4877 ac->highest_zoneidx = gfp_zone(gfp_mask);
4878 ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
4879 ac->nodemask = nodemask;
4880 ac->migratetype = gfp_migratetype(gfp_mask);
4882 if (cpusets_enabled()) {
4883 *alloc_mask |= __GFP_HARDWALL;
4885 * When we are in the interrupt context, it is irrelevant
4886 * to the current task context. It means that any node ok.
4888 if (!in_interrupt() && !ac->nodemask)
4889 ac->nodemask = &cpuset_current_mems_allowed;
4891 *alloc_flags |= ALLOC_CPUSET;
4894 fs_reclaim_acquire(gfp_mask);
4895 fs_reclaim_release(gfp_mask);
4897 might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
4899 if (should_fail_alloc_page(gfp_mask, order))
4902 *alloc_flags = current_alloc_flags(gfp_mask, *alloc_flags);
4904 /* Dirty zone balancing only done in the fast path */
4905 ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
4908 * The preferred zone is used for statistics but crucially it is
4909 * also used as the starting point for the zonelist iterator. It
4910 * may get reset for allocations that ignore memory policies.
4912 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4913 ac->highest_zoneidx, ac->nodemask);
4919 * This is the 'heart' of the zoned buddy allocator.
4922 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
4923 nodemask_t *nodemask)
4926 unsigned int alloc_flags = ALLOC_WMARK_LOW;
4927 gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */
4928 struct alloc_context ac = { };
4931 * There are several places where we assume that the order value is sane
4932 * so bail out early if the request is out of bound.
4934 if (unlikely(order >= MAX_ORDER)) {
4935 WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
4939 gfp_mask &= gfp_allowed_mask;
4940 alloc_mask = gfp_mask;
4941 if (!prepare_alloc_pages(gfp_mask, order, preferred_nid, nodemask, &ac, &alloc_mask, &alloc_flags))
4945 * Forbid the first pass from falling back to types that fragment
4946 * memory until all local zones are considered.
4948 alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp_mask);
4950 /* First allocation attempt */
4951 page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
4956 * Apply scoped allocation constraints. This is mainly about GFP_NOFS
4957 * resp. GFP_NOIO which has to be inherited for all allocation requests
4958 * from a particular context which has been marked by
4959 * memalloc_no{fs,io}_{save,restore}.
4961 alloc_mask = current_gfp_context(gfp_mask);
4962 ac.spread_dirty_pages = false;
4965 * Restore the original nodemask if it was potentially replaced with
4966 * &cpuset_current_mems_allowed to optimize the fast-path attempt.
4968 ac.nodemask = nodemask;
4970 page = __alloc_pages_slowpath(alloc_mask, order, &ac);
4973 if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
4974 unlikely(__memcg_kmem_charge_page(page, gfp_mask, order) != 0)) {
4975 __free_pages(page, order);
4979 trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);
4983 EXPORT_SYMBOL(__alloc_pages_nodemask);
4986 * Common helper functions. Never use with __GFP_HIGHMEM because the returned
4987 * address cannot represent highmem pages. Use alloc_pages and then kmap if
4988 * you need to access high mem.
4990 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
4994 page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, order);
4997 return (unsigned long) page_address(page);
4999 EXPORT_SYMBOL(__get_free_pages);
5001 unsigned long get_zeroed_page(gfp_t gfp_mask)
5003 return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
5005 EXPORT_SYMBOL(get_zeroed_page);
5007 static inline void free_the_page(struct page *page, unsigned int order)
5009 if (order == 0) /* Via pcp? */
5010 free_unref_page(page);
5012 __free_pages_ok(page, order, FPI_NONE);
5015 void __free_pages(struct page *page, unsigned int order)
5017 if (put_page_testzero(page))
5018 free_the_page(page, order);
5019 else if (!PageHead(page))
5021 free_the_page(page + (1 << order), order);
5023 EXPORT_SYMBOL(__free_pages);
5025 void free_pages(unsigned long addr, unsigned int order)
5028 VM_BUG_ON(!virt_addr_valid((void *)addr));
5029 __free_pages(virt_to_page((void *)addr), order);
5033 EXPORT_SYMBOL(free_pages);
5037 * An arbitrary-length arbitrary-offset area of memory which resides
5038 * within a 0 or higher order page. Multiple fragments within that page
5039 * are individually refcounted, in the page's reference counter.
5041 * The page_frag functions below provide a simple allocation framework for
5042 * page fragments. This is used by the network stack and network device
5043 * drivers to provide a backing region of memory for use as either an
5044 * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
5046 static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
5049 struct page *page = NULL;
5050 gfp_t gfp = gfp_mask;
5052 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
5053 gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
5055 page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
5056 PAGE_FRAG_CACHE_MAX_ORDER);
5057 nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
5059 if (unlikely(!page))
5060 page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
5062 nc->va = page ? page_address(page) : NULL;
5067 void __page_frag_cache_drain(struct page *page, unsigned int count)
5069 VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
5071 if (page_ref_sub_and_test(page, count))
5072 free_the_page(page, compound_order(page));
5074 EXPORT_SYMBOL(__page_frag_cache_drain);
5076 void *page_frag_alloc(struct page_frag_cache *nc,
5077 unsigned int fragsz, gfp_t gfp_mask)
5079 unsigned int size = PAGE_SIZE;
5083 if (unlikely(!nc->va)) {
5085 page = __page_frag_cache_refill(nc, gfp_mask);
5089 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
5090 /* if size can vary use size else just use PAGE_SIZE */
5093 /* Even if we own the page, we do not use atomic_set().
5094 * This would break get_page_unless_zero() users.
5096 page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE);
5098 /* reset page count bias and offset to start of new frag */
5099 nc->pfmemalloc = page_is_pfmemalloc(page);
5100 nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
5104 offset = nc->offset - fragsz;
5105 if (unlikely(offset < 0)) {
5106 page = virt_to_page(nc->va);
5108 if (!page_ref_sub_and_test(page, nc->pagecnt_bias))
5111 if (unlikely(nc->pfmemalloc)) {
5112 free_the_page(page, compound_order(page));
5116 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
5117 /* if size can vary use size else just use PAGE_SIZE */
5120 /* OK, page count is 0, we can safely set it */
5121 set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1);
5123 /* reset page count bias and offset to start of new frag */
5124 nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
5125 offset = size - fragsz;
5129 nc->offset = offset;
5131 return nc->va + offset;
5133 EXPORT_SYMBOL(page_frag_alloc);
5136 * Frees a page fragment allocated out of either a compound or order 0 page.
5138 void page_frag_free(void *addr)
5140 struct page *page = virt_to_head_page(addr);
5142 if (unlikely(put_page_testzero(page)))
5143 free_the_page(page, compound_order(page));
5145 EXPORT_SYMBOL(page_frag_free);
5147 static void *make_alloc_exact(unsigned long addr, unsigned int order,
5151 unsigned long alloc_end = addr + (PAGE_SIZE << order);
5152 unsigned long used = addr + PAGE_ALIGN(size);
5154 split_page(virt_to_page((void *)addr), order);
5155 while (used < alloc_end) {
5160 return (void *)addr;
5164 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
5165 * @size: the number of bytes to allocate
5166 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
5168 * This function is similar to alloc_pages(), except that it allocates the
5169 * minimum number of pages to satisfy the request. alloc_pages() can only
5170 * allocate memory in power-of-two pages.
5172 * This function is also limited by MAX_ORDER.
5174 * Memory allocated by this function must be released by free_pages_exact().
5176 * Return: pointer to the allocated area or %NULL in case of error.
5178 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
5180 unsigned int order = get_order(size);
5183 if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
5184 gfp_mask &= ~__GFP_COMP;
5186 addr = __get_free_pages(gfp_mask, order);
5187 return make_alloc_exact(addr, order, size);
5189 EXPORT_SYMBOL(alloc_pages_exact);
5192 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
5194 * @nid: the preferred node ID where memory should be allocated
5195 * @size: the number of bytes to allocate
5196 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
5198 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
5201 * Return: pointer to the allocated area or %NULL in case of error.
5203 void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
5205 unsigned int order = get_order(size);
5208 if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
5209 gfp_mask &= ~__GFP_COMP;
5211 p = alloc_pages_node(nid, gfp_mask, order);
5214 return make_alloc_exact((unsigned long)page_address(p), order, size);
5218 * free_pages_exact - release memory allocated via alloc_pages_exact()
5219 * @virt: the value returned by alloc_pages_exact.
5220 * @size: size of allocation, same value as passed to alloc_pages_exact().
5222 * Release the memory allocated by a previous call to alloc_pages_exact.
5224 void free_pages_exact(void *virt, size_t size)
5226 unsigned long addr = (unsigned long)virt;
5227 unsigned long end = addr + PAGE_ALIGN(size);
5229 while (addr < end) {
5234 EXPORT_SYMBOL(free_pages_exact);
5237 * nr_free_zone_pages - count number of pages beyond high watermark
5238 * @offset: The zone index of the highest zone
5240 * nr_free_zone_pages() counts the number of pages which are beyond the
5241 * high watermark within all zones at or below a given zone index. For each
5242 * zone, the number of pages is calculated as:
5244 * nr_free_zone_pages = managed_pages - high_pages
5246 * Return: number of pages beyond high watermark.
5248 static unsigned long nr_free_zone_pages(int offset)
5253 /* Just pick one node, since fallback list is circular */
5254 unsigned long sum = 0;
5256 struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
5258 for_each_zone_zonelist(zone, z, zonelist, offset) {
5259 unsigned long size = zone_managed_pages(zone);
5260 unsigned long high = high_wmark_pages(zone);
5269 * nr_free_buffer_pages - count number of pages beyond high watermark
5271 * nr_free_buffer_pages() counts the number of pages which are beyond the high
5272 * watermark within ZONE_DMA and ZONE_NORMAL.
5274 * Return: number of pages beyond high watermark within ZONE_DMA and
5277 unsigned long nr_free_buffer_pages(void)
5279 return nr_free_zone_pages(gfp_zone(GFP_USER));
5281 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
5283 static inline void show_node(struct zone *zone)
5285 if (IS_ENABLED(CONFIG_NUMA))
5286 printk("Node %d ", zone_to_nid(zone));
5289 long si_mem_available(void)
5292 unsigned long pagecache;
5293 unsigned long wmark_low = 0;
5294 unsigned long pages[NR_LRU_LISTS];
5295 unsigned long reclaimable;
5299 for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
5300 pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
5303 wmark_low += low_wmark_pages(zone);
5306 * Estimate the amount of memory available for userspace allocations,
5307 * without causing swapping.
5309 available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages;
5312 * Not all the page cache can be freed, otherwise the system will
5313 * start swapping. Assume at least half of the page cache, or the
5314 * low watermark worth of cache, needs to stay.
5316 pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
5317 pagecache -= min(pagecache / 2, wmark_low);
5318 available += pagecache;
5321 * Part of the reclaimable slab and other kernel memory consists of
5322 * items that are in use, and cannot be freed. Cap this estimate at the
5325 reclaimable = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B) +
5326 global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
5327 available += reclaimable - min(reclaimable / 2, wmark_low);
5333 EXPORT_SYMBOL_GPL(si_mem_available);
5335 void si_meminfo(struct sysinfo *val)
5337 val->totalram = totalram_pages();
5338 val->sharedram = global_node_page_state(NR_SHMEM);
5339 val->freeram = global_zone_page_state(NR_FREE_PAGES);
5340 val->bufferram = nr_blockdev_pages();
5341 val->totalhigh = totalhigh_pages();
5342 val->freehigh = nr_free_highpages();
5343 val->mem_unit = PAGE_SIZE;
5346 EXPORT_SYMBOL(si_meminfo);
5349 void si_meminfo_node(struct sysinfo *val, int nid)
5351 int zone_type; /* needs to be signed */
5352 unsigned long managed_pages = 0;
5353 unsigned long managed_highpages = 0;
5354 unsigned long free_highpages = 0;
5355 pg_data_t *pgdat = NODE_DATA(nid);
5357 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
5358 managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]);
5359 val->totalram = managed_pages;
5360 val->sharedram = node_page_state(pgdat, NR_SHMEM);
5361 val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
5362 #ifdef CONFIG_HIGHMEM
5363 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
5364 struct zone *zone = &pgdat->node_zones[zone_type];
5366 if (is_highmem(zone)) {
5367 managed_highpages += zone_managed_pages(zone);
5368 free_highpages += zone_page_state(zone, NR_FREE_PAGES);
5371 val->totalhigh = managed_highpages;
5372 val->freehigh = free_highpages;
5374 val->totalhigh = managed_highpages;
5375 val->freehigh = free_highpages;
5377 val->mem_unit = PAGE_SIZE;
5382 * Determine whether the node should be displayed or not, depending on whether
5383 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
5385 static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask)
5387 if (!(flags & SHOW_MEM_FILTER_NODES))
5391 * no node mask - aka implicit memory numa policy. Do not bother with
5392 * the synchronization - read_mems_allowed_begin - because we do not
5393 * have to be precise here.
5396 nodemask = &cpuset_current_mems_allowed;
5398 return !node_isset(nid, *nodemask);
5401 #define K(x) ((x) << (PAGE_SHIFT-10))
5403 static void show_migration_types(unsigned char type)
5405 static const char types[MIGRATE_TYPES] = {
5406 [MIGRATE_UNMOVABLE] = 'U',
5407 [MIGRATE_MOVABLE] = 'M',
5408 [MIGRATE_RECLAIMABLE] = 'E',
5409 [MIGRATE_HIGHATOMIC] = 'H',
5411 [MIGRATE_CMA] = 'C',
5413 #ifdef CONFIG_MEMORY_ISOLATION
5414 [MIGRATE_ISOLATE] = 'I',
5417 char tmp[MIGRATE_TYPES + 1];
5421 for (i = 0; i < MIGRATE_TYPES; i++) {
5422 if (type & (1 << i))
5427 printk(KERN_CONT "(%s) ", tmp);
5431 * Show free area list (used inside shift_scroll-lock stuff)
5432 * We also calculate the percentage fragmentation. We do this by counting the
5433 * memory on each free list with the exception of the first item on the list.
5436 * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
5439 void show_free_areas(unsigned int filter, nodemask_t *nodemask)
5441 unsigned long free_pcp = 0;
5446 for_each_populated_zone(zone) {
5447 if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5450 for_each_online_cpu(cpu)
5451 free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
5454 printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
5455 " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
5456 " unevictable:%lu dirty:%lu writeback:%lu\n"
5457 " slab_reclaimable:%lu slab_unreclaimable:%lu\n"
5458 " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
5459 " free:%lu free_pcp:%lu free_cma:%lu\n",
5460 global_node_page_state(NR_ACTIVE_ANON),
5461 global_node_page_state(NR_INACTIVE_ANON),
5462 global_node_page_state(NR_ISOLATED_ANON),
5463 global_node_page_state(NR_ACTIVE_FILE),
5464 global_node_page_state(NR_INACTIVE_FILE),
5465 global_node_page_state(NR_ISOLATED_FILE),
5466 global_node_page_state(NR_UNEVICTABLE),
5467 global_node_page_state(NR_FILE_DIRTY),
5468 global_node_page_state(NR_WRITEBACK),
5469 global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B),
5470 global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B),
5471 global_node_page_state(NR_FILE_MAPPED),
5472 global_node_page_state(NR_SHMEM),
5473 global_zone_page_state(NR_PAGETABLE),
5474 global_zone_page_state(NR_BOUNCE),
5475 global_zone_page_state(NR_FREE_PAGES),
5477 global_zone_page_state(NR_FREE_CMA_PAGES));
5479 for_each_online_pgdat(pgdat) {
5480 if (show_mem_node_skip(filter, pgdat->node_id, nodemask))
5484 " active_anon:%lukB"
5485 " inactive_anon:%lukB"
5486 " active_file:%lukB"
5487 " inactive_file:%lukB"
5488 " unevictable:%lukB"
5489 " isolated(anon):%lukB"
5490 " isolated(file):%lukB"
5495 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5497 " shmem_pmdmapped: %lukB"
5500 " writeback_tmp:%lukB"
5501 " kernel_stack:%lukB"
5502 #ifdef CONFIG_SHADOW_CALL_STACK
5503 " shadow_call_stack:%lukB"
5505 " all_unreclaimable? %s"
5508 K(node_page_state(pgdat, NR_ACTIVE_ANON)),
5509 K(node_page_state(pgdat, NR_INACTIVE_ANON)),
5510 K(node_page_state(pgdat, NR_ACTIVE_FILE)),
5511 K(node_page_state(pgdat, NR_INACTIVE_FILE)),
5512 K(node_page_state(pgdat, NR_UNEVICTABLE)),
5513 K(node_page_state(pgdat, NR_ISOLATED_ANON)),
5514 K(node_page_state(pgdat, NR_ISOLATED_FILE)),
5515 K(node_page_state(pgdat, NR_FILE_MAPPED)),
5516 K(node_page_state(pgdat, NR_FILE_DIRTY)),
5517 K(node_page_state(pgdat, NR_WRITEBACK)),
5518 K(node_page_state(pgdat, NR_SHMEM)),
5519 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5520 K(node_page_state(pgdat, NR_SHMEM_THPS) * HPAGE_PMD_NR),
5521 K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)
5523 K(node_page_state(pgdat, NR_ANON_THPS) * HPAGE_PMD_NR),
5525 K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
5526 node_page_state(pgdat, NR_KERNEL_STACK_KB),
5527 #ifdef CONFIG_SHADOW_CALL_STACK
5528 node_page_state(pgdat, NR_KERNEL_SCS_KB),
5530 pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ?
5534 for_each_populated_zone(zone) {
5537 if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5541 for_each_online_cpu(cpu)
5542 free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
5551 " reserved_highatomic:%luKB"
5552 " active_anon:%lukB"
5553 " inactive_anon:%lukB"
5554 " active_file:%lukB"
5555 " inactive_file:%lukB"
5556 " unevictable:%lukB"
5557 " writepending:%lukB"
5568 K(zone_page_state(zone, NR_FREE_PAGES)),
5569 K(min_wmark_pages(zone)),
5570 K(low_wmark_pages(zone)),
5571 K(high_wmark_pages(zone)),
5572 K(zone->nr_reserved_highatomic),
5573 K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)),
5574 K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)),
5575 K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
5576 K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
5577 K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
5578 K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
5579 K(zone->present_pages),
5580 K(zone_managed_pages(zone)),
5581 K(zone_page_state(zone, NR_MLOCK)),
5582 K(zone_page_state(zone, NR_PAGETABLE)),
5583 K(zone_page_state(zone, NR_BOUNCE)),
5585 K(this_cpu_read(zone->pageset->pcp.count)),
5586 K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
5587 printk("lowmem_reserve[]:");
5588 for (i = 0; i < MAX_NR_ZONES; i++)
5589 printk(KERN_CONT " %ld", zone->lowmem_reserve[i]);
5590 printk(KERN_CONT "\n");
5593 for_each_populated_zone(zone) {
5595 unsigned long nr[MAX_ORDER], flags, total = 0;
5596 unsigned char types[MAX_ORDER];
5598 if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5601 printk(KERN_CONT "%s: ", zone->name);
5603 spin_lock_irqsave(&zone->lock, flags);
5604 for (order = 0; order < MAX_ORDER; order++) {
5605 struct free_area *area = &zone->free_area[order];
5608 nr[order] = area->nr_free;
5609 total += nr[order] << order;
5612 for (type = 0; type < MIGRATE_TYPES; type++) {
5613 if (!free_area_empty(area, type))
5614 types[order] |= 1 << type;
5617 spin_unlock_irqrestore(&zone->lock, flags);
5618 for (order = 0; order < MAX_ORDER; order++) {
5619 printk(KERN_CONT "%lu*%lukB ",
5620 nr[order], K(1UL) << order);
5622 show_migration_types(types[order]);
5624 printk(KERN_CONT "= %lukB\n", K(total));
5627 hugetlb_show_meminfo();
5629 printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
5631 show_swap_cache_info();
5634 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
5636 zoneref->zone = zone;
5637 zoneref->zone_idx = zone_idx(zone);
5641 * Builds allocation fallback zone lists.
5643 * Add all populated zones of a node to the zonelist.
5645 static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs)
5648 enum zone_type zone_type = MAX_NR_ZONES;
5653 zone = pgdat->node_zones + zone_type;
5654 if (managed_zone(zone)) {
5655 zoneref_set_zone(zone, &zonerefs[nr_zones++]);
5656 check_highest_zone(zone_type);
5658 } while (zone_type);
5665 static int __parse_numa_zonelist_order(char *s)
5668 * We used to support different zonlists modes but they turned
5669 * out to be just not useful. Let's keep the warning in place
5670 * if somebody still use the cmd line parameter so that we do
5671 * not fail it silently
5673 if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) {
5674 pr_warn("Ignoring unsupported numa_zonelist_order value: %s\n", s);
5680 char numa_zonelist_order[] = "Node";
5683 * sysctl handler for numa_zonelist_order
5685 int numa_zonelist_order_handler(struct ctl_table *table, int write,
5686 void *buffer, size_t *length, loff_t *ppos)
5689 return __parse_numa_zonelist_order(buffer);
5690 return proc_dostring(table, write, buffer, length, ppos);
5694 #define MAX_NODE_LOAD (nr_online_nodes)
5695 static int node_load[MAX_NUMNODES];
5698 * find_next_best_node - find the next node that should appear in a given node's fallback list
5699 * @node: node whose fallback list we're appending
5700 * @used_node_mask: nodemask_t of already used nodes
5702 * We use a number of factors to determine which is the next node that should
5703 * appear on a given node's fallback list. The node should not have appeared
5704 * already in @node's fallback list, and it should be the next closest node
5705 * according to the distance array (which contains arbitrary distance values
5706 * from each node to each node in the system), and should also prefer nodes
5707 * with no CPUs, since presumably they'll have very little allocation pressure
5708 * on them otherwise.
5710 * Return: node id of the found node or %NUMA_NO_NODE if no node is found.
5712 static int find_next_best_node(int node, nodemask_t *used_node_mask)
5715 int min_val = INT_MAX;
5716 int best_node = NUMA_NO_NODE;
5718 /* Use the local node if we haven't already */
5719 if (!node_isset(node, *used_node_mask)) {
5720 node_set(node, *used_node_mask);
5724 for_each_node_state(n, N_MEMORY) {
5726 /* Don't want a node to appear more than once */
5727 if (node_isset(n, *used_node_mask))
5730 /* Use the distance array to find the distance */
5731 val = node_distance(node, n);
5733 /* Penalize nodes under us ("prefer the next node") */
5736 /* Give preference to headless and unused nodes */
5737 if (!cpumask_empty(cpumask_of_node(n)))
5738 val += PENALTY_FOR_NODE_WITH_CPUS;
5740 /* Slight preference for less loaded node */
5741 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
5742 val += node_load[n];
5744 if (val < min_val) {
5751 node_set(best_node, *used_node_mask);
5758 * Build zonelists ordered by node and zones within node.
5759 * This results in maximum locality--normal zone overflows into local
5760 * DMA zone, if any--but risks exhausting DMA zone.
5762 static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order,
5765 struct zoneref *zonerefs;
5768 zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
5770 for (i = 0; i < nr_nodes; i++) {
5773 pg_data_t *node = NODE_DATA(node_order[i]);
5775 nr_zones = build_zonerefs_node(node, zonerefs);
5776 zonerefs += nr_zones;
5778 zonerefs->zone = NULL;
5779 zonerefs->zone_idx = 0;
5783 * Build gfp_thisnode zonelists
5785 static void build_thisnode_zonelists(pg_data_t *pgdat)
5787 struct zoneref *zonerefs;
5790 zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs;
5791 nr_zones = build_zonerefs_node(pgdat, zonerefs);
5792 zonerefs += nr_zones;
5793 zonerefs->zone = NULL;
5794 zonerefs->zone_idx = 0;
5798 * Build zonelists ordered by zone and nodes within zones.
5799 * This results in conserving DMA zone[s] until all Normal memory is
5800 * exhausted, but results in overflowing to remote node while memory
5801 * may still exist in local DMA zone.
5804 static void build_zonelists(pg_data_t *pgdat)
5806 static int node_order[MAX_NUMNODES];
5807 int node, load, nr_nodes = 0;
5808 nodemask_t used_mask = NODE_MASK_NONE;
5809 int local_node, prev_node;
5811 /* NUMA-aware ordering of nodes */
5812 local_node = pgdat->node_id;
5813 load = nr_online_nodes;
5814 prev_node = local_node;
5816 memset(node_order, 0, sizeof(node_order));
5817 while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
5819 * We don't want to pressure a particular node.
5820 * So adding penalty to the first node in same
5821 * distance group to make it round-robin.
5823 if (node_distance(local_node, node) !=
5824 node_distance(local_node, prev_node))
5825 node_load[node] = load;
5827 node_order[nr_nodes++] = node;
5832 build_zonelists_in_node_order(pgdat, node_order, nr_nodes);
5833 build_thisnode_zonelists(pgdat);
5836 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
5838 * Return node id of node used for "local" allocations.
5839 * I.e., first node id of first zone in arg node's generic zonelist.
5840 * Used for initializing percpu 'numa_mem', which is used primarily
5841 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
5843 int local_memory_node(int node)
5847 z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
5848 gfp_zone(GFP_KERNEL),
5850 return zone_to_nid(z->zone);
5854 static void setup_min_unmapped_ratio(void);
5855 static void setup_min_slab_ratio(void);
5856 #else /* CONFIG_NUMA */
5858 static void build_zonelists(pg_data_t *pgdat)
5860 int node, local_node;
5861 struct zoneref *zonerefs;
5864 local_node = pgdat->node_id;
5866 zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
5867 nr_zones = build_zonerefs_node(pgdat, zonerefs);
5868 zonerefs += nr_zones;
5871 * Now we build the zonelist so that it contains the zones
5872 * of all the other nodes.
5873 * We don't want to pressure a particular node, so when
5874 * building the zones for node N, we make sure that the
5875 * zones coming right after the local ones are those from
5876 * node N+1 (modulo N)
5878 for (node = local_node + 1; node < MAX_NUMNODES; node++) {
5879 if (!node_online(node))
5881 nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
5882 zonerefs += nr_zones;
5884 for (node = 0; node < local_node; node++) {
5885 if (!node_online(node))
5887 nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
5888 zonerefs += nr_zones;
5891 zonerefs->zone = NULL;
5892 zonerefs->zone_idx = 0;
5895 #endif /* CONFIG_NUMA */
5898 * Boot pageset table. One per cpu which is going to be used for all
5899 * zones and all nodes. The parameters will be set in such a way
5900 * that an item put on a list will immediately be handed over to
5901 * the buddy list. This is safe since pageset manipulation is done
5902 * with interrupts disabled.
5904 * The boot_pagesets must be kept even after bootup is complete for
5905 * unused processors and/or zones. They do play a role for bootstrapping
5906 * hotplugged processors.
5908 * zoneinfo_show() and maybe other functions do
5909 * not check if the processor is online before following the pageset pointer.
5910 * Other parts of the kernel may not check if the zone is available.
5912 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
5913 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
5914 static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
5916 static void __build_all_zonelists(void *data)
5919 int __maybe_unused cpu;
5920 pg_data_t *self = data;
5921 static DEFINE_SPINLOCK(lock);
5926 memset(node_load, 0, sizeof(node_load));
5930 * This node is hotadded and no memory is yet present. So just
5931 * building zonelists is fine - no need to touch other nodes.
5933 if (self && !node_online(self->node_id)) {
5934 build_zonelists(self);
5936 for_each_online_node(nid) {
5937 pg_data_t *pgdat = NODE_DATA(nid);
5939 build_zonelists(pgdat);
5942 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
5944 * We now know the "local memory node" for each node--
5945 * i.e., the node of the first zone in the generic zonelist.
5946 * Set up numa_mem percpu variable for on-line cpus. During
5947 * boot, only the boot cpu should be on-line; we'll init the
5948 * secondary cpus' numa_mem as they come on-line. During
5949 * node/memory hotplug, we'll fixup all on-line cpus.
5951 for_each_online_cpu(cpu)
5952 set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
5959 static noinline void __init
5960 build_all_zonelists_init(void)
5964 __build_all_zonelists(NULL);
5967 * Initialize the boot_pagesets that are going to be used
5968 * for bootstrapping processors. The real pagesets for
5969 * each zone will be allocated later when the per cpu
5970 * allocator is available.
5972 * boot_pagesets are used also for bootstrapping offline
5973 * cpus if the system is already booted because the pagesets
5974 * are needed to initialize allocators on a specific cpu too.
5975 * F.e. the percpu allocator needs the page allocator which
5976 * needs the percpu allocator in order to allocate its pagesets
5977 * (a chicken-egg dilemma).
5979 for_each_possible_cpu(cpu)
5980 setup_pageset(&per_cpu(boot_pageset, cpu), 0);
5982 mminit_verify_zonelist();
5983 cpuset_init_current_mems_allowed();
5987 * unless system_state == SYSTEM_BOOTING.
5989 * __ref due to call of __init annotated helper build_all_zonelists_init
5990 * [protected by SYSTEM_BOOTING].
5992 void __ref build_all_zonelists(pg_data_t *pgdat)
5994 unsigned long vm_total_pages;
5996 if (system_state == SYSTEM_BOOTING) {
5997 build_all_zonelists_init();
5999 __build_all_zonelists(pgdat);
6000 /* cpuset refresh routine should be here */
6002 /* Get the number of free pages beyond high watermark in all zones. */
6003 vm_total_pages = nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
6005 * Disable grouping by mobility if the number of pages in the
6006 * system is too low to allow the mechanism to work. It would be
6007 * more accurate, but expensive to check per-zone. This check is
6008 * made on memory-hotadd so a system can start with mobility
6009 * disabled and enable it later
6011 if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
6012 page_group_by_mobility_disabled = 1;
6014 page_group_by_mobility_disabled = 0;
6016 pr_info("Built %u zonelists, mobility grouping %s. Total pages: %ld\n",
6018 page_group_by_mobility_disabled ? "off" : "on",
6021 pr_info("Policy zone: %s\n", zone_names[policy_zone]);
6025 /* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
6026 static bool __meminit
6027 overlap_memmap_init(unsigned long zone, unsigned long *pfn)
6029 static struct memblock_region *r;
6031 if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
6032 if (!r || *pfn >= memblock_region_memory_end_pfn(r)) {
6033 for_each_mem_region(r) {
6034 if (*pfn < memblock_region_memory_end_pfn(r))
6038 if (*pfn >= memblock_region_memory_base_pfn(r) &&
6039 memblock_is_mirror(r)) {
6040 *pfn = memblock_region_memory_end_pfn(r);
6048 * Initially all pages are reserved - free ones are freed
6049 * up by memblock_free_all() once the early boot process is
6050 * done. Non-atomic initialization, single-pass.
6052 * All aligned pageblocks are initialized to the specified migratetype
6053 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
6054 * zone stats (e.g., nr_isolate_pageblock) are touched.
6056 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
6057 unsigned long start_pfn, unsigned long zone_end_pfn,
6058 enum meminit_context context,
6059 struct vmem_altmap *altmap, int migratetype)
6061 unsigned long pfn, end_pfn = start_pfn + size;
6064 if (highest_memmap_pfn < end_pfn - 1)
6065 highest_memmap_pfn = end_pfn - 1;
6067 #ifdef CONFIG_ZONE_DEVICE
6069 * Honor reservation requested by the driver for this ZONE_DEVICE
6070 * memory. We limit the total number of pages to initialize to just
6071 * those that might contain the memory mapping. We will defer the
6072 * ZONE_DEVICE page initialization until after we have released
6075 if (zone == ZONE_DEVICE) {
6079 if (start_pfn == altmap->base_pfn)
6080 start_pfn += altmap->reserve;
6081 end_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
6085 for (pfn = start_pfn; pfn < end_pfn; ) {
6087 * There can be holes in boot-time mem_map[]s handed to this
6088 * function. They do not exist on hotplugged memory.
6090 if (context == MEMINIT_EARLY) {
6091 if (overlap_memmap_init(zone, &pfn))
6093 if (defer_init(nid, pfn, zone_end_pfn))
6097 page = pfn_to_page(pfn);
6098 __init_single_page(page, pfn, zone, nid);
6099 if (context == MEMINIT_HOTPLUG)
6100 __SetPageReserved(page);
6103 * Usually, we want to mark the pageblock MIGRATE_MOVABLE,
6104 * such that unmovable allocations won't be scattered all
6105 * over the place during system boot.
6107 if (IS_ALIGNED(pfn, pageblock_nr_pages)) {
6108 set_pageblock_migratetype(page, migratetype);
6115 #ifdef CONFIG_ZONE_DEVICE
6116 void __ref memmap_init_zone_device(struct zone *zone,
6117 unsigned long start_pfn,
6118 unsigned long nr_pages,
6119 struct dev_pagemap *pgmap)
6121 unsigned long pfn, end_pfn = start_pfn + nr_pages;
6122 struct pglist_data *pgdat = zone->zone_pgdat;
6123 struct vmem_altmap *altmap = pgmap_altmap(pgmap);
6124 unsigned long zone_idx = zone_idx(zone);
6125 unsigned long start = jiffies;
6126 int nid = pgdat->node_id;
6128 if (WARN_ON_ONCE(!pgmap || zone_idx(zone) != ZONE_DEVICE))
6132 * The call to memmap_init should have already taken care
6133 * of the pages reserved for the memmap, so we can just jump to
6134 * the end of that region and start processing the device pages.
6137 start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
6138 nr_pages = end_pfn - start_pfn;
6141 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
6142 struct page *page = pfn_to_page(pfn);
6144 __init_single_page(page, pfn, zone_idx, nid);
6147 * Mark page reserved as it will need to wait for onlining
6148 * phase for it to be fully associated with a zone.
6150 * We can use the non-atomic __set_bit operation for setting
6151 * the flag as we are still initializing the pages.
6153 __SetPageReserved(page);
6156 * ZONE_DEVICE pages union ->lru with a ->pgmap back pointer
6157 * and zone_device_data. It is a bug if a ZONE_DEVICE page is
6158 * ever freed or placed on a driver-private list.
6160 page->pgmap = pgmap;
6161 page->zone_device_data = NULL;
6164 * Mark the block movable so that blocks are reserved for
6165 * movable at startup. This will force kernel allocations
6166 * to reserve their blocks rather than leaking throughout
6167 * the address space during boot when many long-lived
6168 * kernel allocations are made.
6170 * Please note that MEMINIT_HOTPLUG path doesn't clear memmap
6171 * because this is done early in section_activate()
6173 if (IS_ALIGNED(pfn, pageblock_nr_pages)) {
6174 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
6179 pr_info("%s initialised %lu pages in %ums\n", __func__,
6180 nr_pages, jiffies_to_msecs(jiffies - start));
6184 static void __meminit zone_init_free_lists(struct zone *zone)
6186 unsigned int order, t;
6187 for_each_migratetype_order(order, t) {
6188 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
6189 zone->free_area[order].nr_free = 0;
6193 #if !defined(CONFIG_FLAT_NODE_MEM_MAP)
6195 * Only struct pages that correspond to ranges defined by memblock.memory
6196 * are zeroed and initialized by going through __init_single_page() during
6197 * memmap_init_zone_range().
6199 * But, there could be struct pages that correspond to holes in
6200 * memblock.memory. This can happen because of the following reasons:
6201 * - physical memory bank size is not necessarily the exact multiple of the
6202 * arbitrary section size
6203 * - early reserved memory may not be listed in memblock.memory
6204 * - memory layouts defined with memmap= kernel parameter may not align
6205 * nicely with memmap sections
6207 * Explicitly initialize those struct pages so that:
6208 * - PG_Reserved is set
6209 * - zone and node links point to zone and node that span the page if the
6210 * hole is in the middle of a zone
6211 * - zone and node links point to adjacent zone/node if the hole falls on
6212 * the zone boundary; the pages in such holes will be prepended to the
6213 * zone/node above the hole except for the trailing pages in the last
6214 * section that will be appended to the zone/node below.
6216 static void __init init_unavailable_range(unsigned long spfn,
6223 for (pfn = spfn; pfn < epfn; pfn++) {
6224 if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
6225 pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
6226 + pageblock_nr_pages - 1;
6229 __init_single_page(pfn_to_page(pfn), pfn, zone, node);
6230 __SetPageReserved(pfn_to_page(pfn));
6235 pr_info("On node %d, zone %s: %lld pages in unavailable ranges",
6236 node, zone_names[zone], pgcnt);
6239 static inline void init_unavailable_range(unsigned long spfn,
6246 static void __init memmap_init_zone_range(struct zone *zone,
6247 unsigned long start_pfn,
6248 unsigned long end_pfn,
6249 unsigned long *hole_pfn)
6251 unsigned long zone_start_pfn = zone->zone_start_pfn;
6252 unsigned long zone_end_pfn = zone_start_pfn + zone->spanned_pages;
6253 int nid = zone_to_nid(zone), zone_id = zone_idx(zone);
6255 start_pfn = clamp(start_pfn, zone_start_pfn, zone_end_pfn);
6256 end_pfn = clamp(end_pfn, zone_start_pfn, zone_end_pfn);
6258 if (start_pfn >= end_pfn)
6261 memmap_init_zone(end_pfn - start_pfn, nid, zone_id, start_pfn,
6262 zone_end_pfn, MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
6264 if (*hole_pfn < start_pfn)
6265 init_unavailable_range(*hole_pfn, start_pfn, zone_id, nid);
6267 *hole_pfn = end_pfn;
6270 void __init __weak memmap_init(void)
6272 unsigned long start_pfn, end_pfn;
6273 unsigned long hole_pfn = 0;
6274 int i, j, zone_id, nid;
6276 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
6277 struct pglist_data *node = NODE_DATA(nid);
6279 for (j = 0; j < MAX_NR_ZONES; j++) {
6280 struct zone *zone = node->node_zones + j;
6282 if (!populated_zone(zone))
6285 memmap_init_zone_range(zone, start_pfn, end_pfn,
6291 #ifdef CONFIG_SPARSEMEM
6293 * Initialize the memory map for hole in the range [memory_end,
6295 * Append the pages in this hole to the highest zone in the last
6297 * The call to init_unavailable_range() is outside the ifdef to
6298 * silence the compiler warining about zone_id set but not used;
6299 * for FLATMEM it is a nop anyway
6301 end_pfn = round_up(end_pfn, PAGES_PER_SECTION);
6302 if (hole_pfn < end_pfn)
6304 init_unavailable_range(hole_pfn, end_pfn, zone_id, nid);
6307 /* A stub for backwards compatibility with custom implementatin on IA-64 */
6308 void __meminit __weak arch_memmap_init(unsigned long size, int nid,
6310 unsigned long range_start_pfn)
6314 static int zone_batchsize(struct zone *zone)
6320 * The per-cpu-pages pools are set to around 1000th of the
6323 batch = zone_managed_pages(zone) / 1024;
6324 /* But no more than a meg. */
6325 if (batch * PAGE_SIZE > 1024 * 1024)
6326 batch = (1024 * 1024) / PAGE_SIZE;
6327 batch /= 4; /* We effectively *= 4 below */
6332 * Clamp the batch to a 2^n - 1 value. Having a power
6333 * of 2 value was found to be more likely to have
6334 * suboptimal cache aliasing properties in some cases.
6336 * For example if 2 tasks are alternately allocating
6337 * batches of pages, one task can end up with a lot
6338 * of pages of one half of the possible page colors
6339 * and the other with pages of the other colors.
6341 batch = rounddown_pow_of_two(batch + batch/2) - 1;
6346 /* The deferral and batching of frees should be suppressed under NOMMU
6349 * The problem is that NOMMU needs to be able to allocate large chunks
6350 * of contiguous memory as there's no hardware page translation to
6351 * assemble apparent contiguous memory from discontiguous pages.
6353 * Queueing large contiguous runs of pages for batching, however,
6354 * causes the pages to actually be freed in smaller chunks. As there
6355 * can be a significant delay between the individual batches being
6356 * recycled, this leads to the once large chunks of space being
6357 * fragmented and becoming unavailable for high-order allocations.
6364 * pcp->high and pcp->batch values are related and dependent on one another:
6365 * ->batch must never be higher then ->high.
6366 * The following function updates them in a safe manner without read side
6369 * Any new users of pcp->batch and pcp->high should ensure they can cope with
6370 * those fields changing asynchronously (acording to the above rule).
6372 * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
6373 * outside of boot time (or some other assurance that no concurrent updaters
6376 static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
6377 unsigned long batch)
6379 /* start with a fail safe value for batch */
6383 /* Update high, then batch, in order */
6390 /* a companion to pageset_set_high() */
6391 static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
6393 pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
6396 static void pageset_init(struct per_cpu_pageset *p)
6398 struct per_cpu_pages *pcp;
6401 memset(p, 0, sizeof(*p));
6404 for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
6405 INIT_LIST_HEAD(&pcp->lists[migratetype]);
6408 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
6411 pageset_set_batch(p, batch);
6415 * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
6416 * to the value high for the pageset p.
6418 static void pageset_set_high(struct per_cpu_pageset *p,
6421 unsigned long batch = max(1UL, high / 4);
6422 if ((high / 4) > (PAGE_SHIFT * 8))
6423 batch = PAGE_SHIFT * 8;
6425 pageset_update(&p->pcp, high, batch);
6428 static void pageset_set_high_and_batch(struct zone *zone,
6429 struct per_cpu_pageset *pcp)
6431 if (percpu_pagelist_fraction)
6432 pageset_set_high(pcp,
6433 (zone_managed_pages(zone) /
6434 percpu_pagelist_fraction));
6436 pageset_set_batch(pcp, zone_batchsize(zone));
6439 static void __meminit zone_pageset_init(struct zone *zone, int cpu)
6441 struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
6444 pageset_set_high_and_batch(zone, pcp);
6447 void __meminit setup_zone_pageset(struct zone *zone)
6450 zone->pageset = alloc_percpu(struct per_cpu_pageset);
6451 for_each_possible_cpu(cpu)
6452 zone_pageset_init(zone, cpu);
6456 * Allocate per cpu pagesets and initialize them.
6457 * Before this call only boot pagesets were available.
6459 void __init setup_per_cpu_pageset(void)
6461 struct pglist_data *pgdat;
6463 int __maybe_unused cpu;
6465 for_each_populated_zone(zone)
6466 setup_zone_pageset(zone);
6470 * Unpopulated zones continue using the boot pagesets.
6471 * The numa stats for these pagesets need to be reset.
6472 * Otherwise, they will end up skewing the stats of
6473 * the nodes these zones are associated with.
6475 for_each_possible_cpu(cpu) {
6476 struct per_cpu_pageset *pcp = &per_cpu(boot_pageset, cpu);
6477 memset(pcp->vm_numa_stat_diff, 0,
6478 sizeof(pcp->vm_numa_stat_diff));
6482 for_each_online_pgdat(pgdat)
6483 pgdat->per_cpu_nodestats =
6484 alloc_percpu(struct per_cpu_nodestat);
6487 static __meminit void zone_pcp_init(struct zone *zone)
6490 * per cpu subsystem is not up at this point. The following code
6491 * relies on the ability of the linker to provide the
6492 * offset of a (static) per cpu variable into the per cpu area.
6494 zone->pageset = &boot_pageset;
6496 if (populated_zone(zone))
6497 printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n",
6498 zone->name, zone->present_pages,
6499 zone_batchsize(zone));
6502 void __meminit init_currently_empty_zone(struct zone *zone,
6503 unsigned long zone_start_pfn,
6506 struct pglist_data *pgdat = zone->zone_pgdat;
6507 int zone_idx = zone_idx(zone) + 1;
6509 if (zone_idx > pgdat->nr_zones)
6510 pgdat->nr_zones = zone_idx;
6512 zone->zone_start_pfn = zone_start_pfn;
6514 mminit_dprintk(MMINIT_TRACE, "memmap_init",
6515 "Initialising map node %d zone %lu pfns %lu -> %lu\n",
6517 (unsigned long)zone_idx(zone),
6518 zone_start_pfn, (zone_start_pfn + size));
6520 zone_init_free_lists(zone);
6521 zone->initialized = 1;
6525 * get_pfn_range_for_nid - Return the start and end page frames for a node
6526 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
6527 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
6528 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
6530 * It returns the start and end page frame of a node based on information
6531 * provided by memblock_set_node(). If called for a node
6532 * with no available memory, a warning is printed and the start and end
6535 void __init get_pfn_range_for_nid(unsigned int nid,
6536 unsigned long *start_pfn, unsigned long *end_pfn)
6538 unsigned long this_start_pfn, this_end_pfn;
6544 for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
6545 *start_pfn = min(*start_pfn, this_start_pfn);
6546 *end_pfn = max(*end_pfn, this_end_pfn);
6549 if (*start_pfn == -1UL)
6554 * This finds a zone that can be used for ZONE_MOVABLE pages. The
6555 * assumption is made that zones within a node are ordered in monotonic
6556 * increasing memory addresses so that the "highest" populated zone is used
6558 static void __init find_usable_zone_for_movable(void)
6561 for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
6562 if (zone_index == ZONE_MOVABLE)
6565 if (arch_zone_highest_possible_pfn[zone_index] >
6566 arch_zone_lowest_possible_pfn[zone_index])
6570 VM_BUG_ON(zone_index == -1);
6571 movable_zone = zone_index;
6575 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
6576 * because it is sized independent of architecture. Unlike the other zones,
6577 * the starting point for ZONE_MOVABLE is not fixed. It may be different
6578 * in each node depending on the size of each node and how evenly kernelcore
6579 * is distributed. This helper function adjusts the zone ranges
6580 * provided by the architecture for a given node by using the end of the
6581 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
6582 * zones within a node are in order of monotonic increases memory addresses
6584 static void __init adjust_zone_range_for_zone_movable(int nid,
6585 unsigned long zone_type,
6586 unsigned long node_start_pfn,
6587 unsigned long node_end_pfn,
6588 unsigned long *zone_start_pfn,
6589 unsigned long *zone_end_pfn)
6591 /* Only adjust if ZONE_MOVABLE is on this node */
6592 if (zone_movable_pfn[nid]) {
6593 /* Size ZONE_MOVABLE */
6594 if (zone_type == ZONE_MOVABLE) {
6595 *zone_start_pfn = zone_movable_pfn[nid];
6596 *zone_end_pfn = min(node_end_pfn,
6597 arch_zone_highest_possible_pfn[movable_zone]);
6599 /* Adjust for ZONE_MOVABLE starting within this range */
6600 } else if (!mirrored_kernelcore &&
6601 *zone_start_pfn < zone_movable_pfn[nid] &&
6602 *zone_end_pfn > zone_movable_pfn[nid]) {
6603 *zone_end_pfn = zone_movable_pfn[nid];
6605 /* Check if this whole range is within ZONE_MOVABLE */
6606 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
6607 *zone_start_pfn = *zone_end_pfn;
6612 * Return the number of pages a zone spans in a node, including holes
6613 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
6615 static unsigned long __init zone_spanned_pages_in_node(int nid,
6616 unsigned long zone_type,
6617 unsigned long node_start_pfn,
6618 unsigned long node_end_pfn,
6619 unsigned long *zone_start_pfn,
6620 unsigned long *zone_end_pfn)
6622 unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
6623 unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
6624 /* When hotadd a new node from cpu_up(), the node should be empty */
6625 if (!node_start_pfn && !node_end_pfn)
6628 /* Get the start and end of the zone */
6629 *zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
6630 *zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
6631 adjust_zone_range_for_zone_movable(nid, zone_type,
6632 node_start_pfn, node_end_pfn,
6633 zone_start_pfn, zone_end_pfn);
6635 /* Check that this node has pages within the zone's required range */
6636 if (*zone_end_pfn < node_start_pfn || *zone_start_pfn > node_end_pfn)
6639 /* Move the zone boundaries inside the node if necessary */
6640 *zone_end_pfn = min(*zone_end_pfn, node_end_pfn);
6641 *zone_start_pfn = max(*zone_start_pfn, node_start_pfn);
6643 /* Return the spanned pages */
6644 return *zone_end_pfn - *zone_start_pfn;
6648 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
6649 * then all holes in the requested range will be accounted for.
6651 unsigned long __init __absent_pages_in_range(int nid,
6652 unsigned long range_start_pfn,
6653 unsigned long range_end_pfn)
6655 unsigned long nr_absent = range_end_pfn - range_start_pfn;
6656 unsigned long start_pfn, end_pfn;
6659 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
6660 start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
6661 end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
6662 nr_absent -= end_pfn - start_pfn;
6668 * absent_pages_in_range - Return number of page frames in holes within a range
6669 * @start_pfn: The start PFN to start searching for holes
6670 * @end_pfn: The end PFN to stop searching for holes
6672 * Return: the number of pages frames in memory holes within a range.
6674 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
6675 unsigned long end_pfn)
6677 return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
6680 /* Return the number of page frames in holes in a zone on a node */
6681 static unsigned long __init zone_absent_pages_in_node(int nid,
6682 unsigned long zone_type,
6683 unsigned long node_start_pfn,
6684 unsigned long node_end_pfn)
6686 unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
6687 unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
6688 unsigned long zone_start_pfn, zone_end_pfn;
6689 unsigned long nr_absent;
6691 /* When hotadd a new node from cpu_up(), the node should be empty */
6692 if (!node_start_pfn && !node_end_pfn)
6695 zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
6696 zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
6698 adjust_zone_range_for_zone_movable(nid, zone_type,
6699 node_start_pfn, node_end_pfn,
6700 &zone_start_pfn, &zone_end_pfn);
6701 nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
6704 * ZONE_MOVABLE handling.
6705 * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
6708 if (mirrored_kernelcore && zone_movable_pfn[nid]) {
6709 unsigned long start_pfn, end_pfn;
6710 struct memblock_region *r;
6712 for_each_mem_region(r) {
6713 start_pfn = clamp(memblock_region_memory_base_pfn(r),
6714 zone_start_pfn, zone_end_pfn);
6715 end_pfn = clamp(memblock_region_memory_end_pfn(r),
6716 zone_start_pfn, zone_end_pfn);
6718 if (zone_type == ZONE_MOVABLE &&
6719 memblock_is_mirror(r))
6720 nr_absent += end_pfn - start_pfn;
6722 if (zone_type == ZONE_NORMAL &&
6723 !memblock_is_mirror(r))
6724 nr_absent += end_pfn - start_pfn;
6731 static void __init calculate_node_totalpages(struct pglist_data *pgdat,
6732 unsigned long node_start_pfn,
6733 unsigned long node_end_pfn)
6735 unsigned long realtotalpages = 0, totalpages = 0;
6738 for (i = 0; i < MAX_NR_ZONES; i++) {
6739 struct zone *zone = pgdat->node_zones + i;
6740 unsigned long zone_start_pfn, zone_end_pfn;
6741 unsigned long spanned, absent;
6742 unsigned long size, real_size;
6744 spanned = zone_spanned_pages_in_node(pgdat->node_id, i,
6749 absent = zone_absent_pages_in_node(pgdat->node_id, i,
6754 real_size = size - absent;
6757 zone->zone_start_pfn = zone_start_pfn;
6759 zone->zone_start_pfn = 0;
6760 zone->spanned_pages = size;
6761 zone->present_pages = real_size;
6764 realtotalpages += real_size;
6767 pgdat->node_spanned_pages = totalpages;
6768 pgdat->node_present_pages = realtotalpages;
6769 printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
6773 #ifndef CONFIG_SPARSEMEM
6775 * Calculate the size of the zone->blockflags rounded to an unsigned long
6776 * Start by making sure zonesize is a multiple of pageblock_order by rounding
6777 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
6778 * round what is now in bits to nearest long in bits, then return it in
6781 static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
6783 unsigned long usemapsize;
6785 zonesize += zone_start_pfn & (pageblock_nr_pages-1);
6786 usemapsize = roundup(zonesize, pageblock_nr_pages);
6787 usemapsize = usemapsize >> pageblock_order;
6788 usemapsize *= NR_PAGEBLOCK_BITS;
6789 usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
6791 return usemapsize / 8;
6794 static void __ref setup_usemap(struct pglist_data *pgdat,
6796 unsigned long zone_start_pfn,
6797 unsigned long zonesize)
6799 unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
6800 zone->pageblock_flags = NULL;
6802 zone->pageblock_flags =
6803 memblock_alloc_node(usemapsize, SMP_CACHE_BYTES,
6805 if (!zone->pageblock_flags)
6806 panic("Failed to allocate %ld bytes for zone %s pageblock flags on node %d\n",
6807 usemapsize, zone->name, pgdat->node_id);
6811 static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
6812 unsigned long zone_start_pfn, unsigned long zonesize) {}
6813 #endif /* CONFIG_SPARSEMEM */
6815 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
6817 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
6818 void __init set_pageblock_order(void)
6822 /* Check that pageblock_nr_pages has not already been setup */
6823 if (pageblock_order)
6826 if (HPAGE_SHIFT > PAGE_SHIFT)
6827 order = HUGETLB_PAGE_ORDER;
6829 order = MAX_ORDER - 1;
6832 * Assume the largest contiguous order of interest is a huge page.
6833 * This value may be variable depending on boot parameters on IA64 and
6836 pageblock_order = order;
6838 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
6841 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
6842 * is unused as pageblock_order is set at compile-time. See
6843 * include/linux/pageblock-flags.h for the values of pageblock_order based on
6846 void __init set_pageblock_order(void)
6850 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
6852 static unsigned long __init calc_memmap_size(unsigned long spanned_pages,
6853 unsigned long present_pages)
6855 unsigned long pages = spanned_pages;
6858 * Provide a more accurate estimation if there are holes within
6859 * the zone and SPARSEMEM is in use. If there are holes within the
6860 * zone, each populated memory region may cost us one or two extra
6861 * memmap pages due to alignment because memmap pages for each
6862 * populated regions may not be naturally aligned on page boundary.
6863 * So the (present_pages >> 4) heuristic is a tradeoff for that.
6865 if (spanned_pages > present_pages + (present_pages >> 4) &&
6866 IS_ENABLED(CONFIG_SPARSEMEM))
6867 pages = present_pages;
6869 return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
6872 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6873 static void pgdat_init_split_queue(struct pglist_data *pgdat)
6875 struct deferred_split *ds_queue = &pgdat->deferred_split_queue;
6877 spin_lock_init(&ds_queue->split_queue_lock);
6878 INIT_LIST_HEAD(&ds_queue->split_queue);
6879 ds_queue->split_queue_len = 0;
6882 static void pgdat_init_split_queue(struct pglist_data *pgdat) {}
6885 #ifdef CONFIG_COMPACTION
6886 static void pgdat_init_kcompactd(struct pglist_data *pgdat)
6888 init_waitqueue_head(&pgdat->kcompactd_wait);
6891 static void pgdat_init_kcompactd(struct pglist_data *pgdat) {}
6894 static void __meminit pgdat_init_internals(struct pglist_data *pgdat)
6896 pgdat_resize_init(pgdat);
6898 pgdat_init_split_queue(pgdat);
6899 pgdat_init_kcompactd(pgdat);
6901 init_waitqueue_head(&pgdat->kswapd_wait);
6902 init_waitqueue_head(&pgdat->pfmemalloc_wait);
6904 pgdat_page_ext_init(pgdat);
6905 spin_lock_init(&pgdat->lru_lock);
6906 lruvec_init(&pgdat->__lruvec);
6909 static void __meminit zone_init_internals(struct zone *zone, enum zone_type idx, int nid,
6910 unsigned long remaining_pages)
6912 atomic_long_set(&zone->managed_pages, remaining_pages);
6913 zone_set_nid(zone, nid);
6914 zone->name = zone_names[idx];
6915 zone->zone_pgdat = NODE_DATA(nid);
6916 spin_lock_init(&zone->lock);
6917 zone_seqlock_init(zone);
6918 zone_pcp_init(zone);
6922 * Set up the zone data structures
6923 * - init pgdat internals
6924 * - init all zones belonging to this node
6926 * NOTE: this function is only called during memory hotplug
6928 #ifdef CONFIG_MEMORY_HOTPLUG
6929 void __ref free_area_init_core_hotplug(int nid)
6932 pg_data_t *pgdat = NODE_DATA(nid);
6934 pgdat_init_internals(pgdat);
6935 for (z = 0; z < MAX_NR_ZONES; z++)
6936 zone_init_internals(&pgdat->node_zones[z], z, nid, 0);
6941 * Set up the zone data structures:
6942 * - mark all pages reserved
6943 * - mark all memory queues empty
6944 * - clear the memory bitmaps
6946 * NOTE: pgdat should get zeroed by caller.
6947 * NOTE: this function is only called during early init.
6949 static void __init free_area_init_core(struct pglist_data *pgdat)
6952 int nid = pgdat->node_id;
6954 pgdat_init_internals(pgdat);
6955 pgdat->per_cpu_nodestats = &boot_nodestats;
6957 for (j = 0; j < MAX_NR_ZONES; j++) {
6958 struct zone *zone = pgdat->node_zones + j;
6959 unsigned long size, freesize, memmap_pages;
6960 unsigned long zone_start_pfn = zone->zone_start_pfn;
6962 size = zone->spanned_pages;
6963 freesize = zone->present_pages;
6966 * Adjust freesize so that it accounts for how much memory
6967 * is used by this zone for memmap. This affects the watermark
6968 * and per-cpu initialisations
6970 memmap_pages = calc_memmap_size(size, freesize);
6971 if (!is_highmem_idx(j)) {
6972 if (freesize >= memmap_pages) {
6973 freesize -= memmap_pages;
6976 " %s zone: %lu pages used for memmap\n",
6977 zone_names[j], memmap_pages);
6979 pr_warn(" %s zone: %lu pages exceeds freesize %lu\n",
6980 zone_names[j], memmap_pages, freesize);
6983 /* Account for reserved pages */
6984 if (j == 0 && freesize > dma_reserve) {
6985 freesize -= dma_reserve;
6986 printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
6987 zone_names[0], dma_reserve);
6990 if (!is_highmem_idx(j))
6991 nr_kernel_pages += freesize;
6992 /* Charge for highmem memmap if there are enough kernel pages */
6993 else if (nr_kernel_pages > memmap_pages * 2)
6994 nr_kernel_pages -= memmap_pages;
6995 nr_all_pages += freesize;
6998 * Set an approximate value for lowmem here, it will be adjusted
6999 * when the bootmem allocator frees pages into the buddy system.
7000 * And all highmem pages will be managed by the buddy system.
7002 zone_init_internals(zone, j, nid, freesize);
7007 set_pageblock_order();
7008 setup_usemap(pgdat, zone, zone_start_pfn, size);
7009 init_currently_empty_zone(zone, zone_start_pfn, size);
7010 arch_memmap_init(size, nid, j, zone_start_pfn);
7014 #ifdef CONFIG_FLAT_NODE_MEM_MAP
7015 static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
7017 unsigned long __maybe_unused start = 0;
7018 unsigned long __maybe_unused offset = 0;
7020 /* Skip empty nodes */
7021 if (!pgdat->node_spanned_pages)
7024 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
7025 offset = pgdat->node_start_pfn - start;
7026 /* ia64 gets its own node_mem_map, before this, without bootmem */
7027 if (!pgdat->node_mem_map) {
7028 unsigned long size, end;
7032 * The zone's endpoints aren't required to be MAX_ORDER
7033 * aligned but the node_mem_map endpoints must be in order
7034 * for the buddy allocator to function correctly.
7036 end = pgdat_end_pfn(pgdat);
7037 end = ALIGN(end, MAX_ORDER_NR_PAGES);
7038 size = (end - start) * sizeof(struct page);
7039 map = memblock_alloc_node(size, SMP_CACHE_BYTES,
7042 panic("Failed to allocate %ld bytes for node %d memory map\n",
7043 size, pgdat->node_id);
7044 pgdat->node_mem_map = map + offset;
7046 pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
7047 __func__, pgdat->node_id, (unsigned long)pgdat,
7048 (unsigned long)pgdat->node_mem_map);
7049 #ifndef CONFIG_NEED_MULTIPLE_NODES
7051 * With no DISCONTIG, the global mem_map is just set as node 0's
7053 if (pgdat == NODE_DATA(0)) {
7054 mem_map = NODE_DATA(0)->node_mem_map;
7055 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
7061 static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { }
7062 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
7064 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
7065 static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
7067 pgdat->first_deferred_pfn = ULONG_MAX;
7070 static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
7073 static void __init free_area_init_node(int nid)
7075 pg_data_t *pgdat = NODE_DATA(nid);
7076 unsigned long start_pfn = 0;
7077 unsigned long end_pfn = 0;
7079 /* pg_data_t should be reset to zero when it's allocated */
7080 WARN_ON(pgdat->nr_zones || pgdat->kswapd_highest_zoneidx);
7082 get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
7084 pgdat->node_id = nid;
7085 pgdat->node_start_pfn = start_pfn;
7086 pgdat->per_cpu_nodestats = NULL;
7088 pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
7089 (u64)start_pfn << PAGE_SHIFT,
7090 end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
7091 calculate_node_totalpages(pgdat, start_pfn, end_pfn);
7093 alloc_node_mem_map(pgdat);
7094 pgdat_set_deferred_range(pgdat);
7096 free_area_init_core(pgdat);
7099 void __init free_area_init_memoryless_node(int nid)
7101 free_area_init_node(nid);
7104 #if MAX_NUMNODES > 1
7106 * Figure out the number of possible node ids.
7108 void __init setup_nr_node_ids(void)
7110 unsigned int highest;
7112 highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES);
7113 nr_node_ids = highest + 1;
7118 * node_map_pfn_alignment - determine the maximum internode alignment
7120 * This function should be called after node map is populated and sorted.
7121 * It calculates the maximum power of two alignment which can distinguish
7124 * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
7125 * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)). If the
7126 * nodes are shifted by 256MiB, 256MiB. Note that if only the last node is
7127 * shifted, 1GiB is enough and this function will indicate so.
7129 * This is used to test whether pfn -> nid mapping of the chosen memory
7130 * model has fine enough granularity to avoid incorrect mapping for the
7131 * populated node map.
7133 * Return: the determined alignment in pfn's. 0 if there is no alignment
7134 * requirement (single node).
7136 unsigned long __init node_map_pfn_alignment(void)
7138 unsigned long accl_mask = 0, last_end = 0;
7139 unsigned long start, end, mask;
7140 int last_nid = NUMA_NO_NODE;
7143 for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
7144 if (!start || last_nid < 0 || last_nid == nid) {
7151 * Start with a mask granular enough to pin-point to the
7152 * start pfn and tick off bits one-by-one until it becomes
7153 * too coarse to separate the current node from the last.
7155 mask = ~((1 << __ffs(start)) - 1);
7156 while (mask && last_end <= (start & (mask << 1)))
7159 /* accumulate all internode masks */
7163 /* convert mask to number of pages */
7164 return ~accl_mask + 1;
7168 * find_min_pfn_with_active_regions - Find the minimum PFN registered
7170 * Return: the minimum PFN based on information provided via
7171 * memblock_set_node().
7173 unsigned long __init find_min_pfn_with_active_regions(void)
7175 return PHYS_PFN(memblock_start_of_DRAM());
7179 * early_calculate_totalpages()
7180 * Sum pages in active regions for movable zone.
7181 * Populate N_MEMORY for calculating usable_nodes.
7183 static unsigned long __init early_calculate_totalpages(void)
7185 unsigned long totalpages = 0;
7186 unsigned long start_pfn, end_pfn;
7189 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
7190 unsigned long pages = end_pfn - start_pfn;
7192 totalpages += pages;
7194 node_set_state(nid, N_MEMORY);
7200 * Find the PFN the Movable zone begins in each node. Kernel memory
7201 * is spread evenly between nodes as long as the nodes have enough
7202 * memory. When they don't, some nodes will have more kernelcore than
7205 static void __init find_zone_movable_pfns_for_nodes(void)
7208 unsigned long usable_startpfn;
7209 unsigned long kernelcore_node, kernelcore_remaining;
7210 /* save the state before borrow the nodemask */
7211 nodemask_t saved_node_state = node_states[N_MEMORY];
7212 unsigned long totalpages = early_calculate_totalpages();
7213 int usable_nodes = nodes_weight(node_states[N_MEMORY]);
7214 struct memblock_region *r;
7216 /* Need to find movable_zone earlier when movable_node is specified. */
7217 find_usable_zone_for_movable();
7220 * If movable_node is specified, ignore kernelcore and movablecore
7223 if (movable_node_is_enabled()) {
7224 for_each_mem_region(r) {
7225 if (!memblock_is_hotpluggable(r))
7228 nid = memblock_get_region_node(r);
7230 usable_startpfn = PFN_DOWN(r->base);
7231 zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
7232 min(usable_startpfn, zone_movable_pfn[nid]) :
7240 * If kernelcore=mirror is specified, ignore movablecore option
7242 if (mirrored_kernelcore) {
7243 bool mem_below_4gb_not_mirrored = false;
7245 for_each_mem_region(r) {
7246 if (memblock_is_mirror(r))
7249 nid = memblock_get_region_node(r);
7251 usable_startpfn = memblock_region_memory_base_pfn(r);
7253 if (usable_startpfn < 0x100000) {
7254 mem_below_4gb_not_mirrored = true;
7258 zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
7259 min(usable_startpfn, zone_movable_pfn[nid]) :
7263 if (mem_below_4gb_not_mirrored)
7264 pr_warn("This configuration results in unmirrored kernel memory.\n");
7270 * If kernelcore=nn% or movablecore=nn% was specified, calculate the
7271 * amount of necessary memory.
7273 if (required_kernelcore_percent)
7274 required_kernelcore = (totalpages * 100 * required_kernelcore_percent) /
7276 if (required_movablecore_percent)
7277 required_movablecore = (totalpages * 100 * required_movablecore_percent) /
7281 * If movablecore= was specified, calculate what size of
7282 * kernelcore that corresponds so that memory usable for
7283 * any allocation type is evenly spread. If both kernelcore
7284 * and movablecore are specified, then the value of kernelcore
7285 * will be used for required_kernelcore if it's greater than
7286 * what movablecore would have allowed.
7288 if (required_movablecore) {
7289 unsigned long corepages;
7292 * Round-up so that ZONE_MOVABLE is at least as large as what
7293 * was requested by the user
7295 required_movablecore =
7296 roundup(required_movablecore, MAX_ORDER_NR_PAGES);
7297 required_movablecore = min(totalpages, required_movablecore);
7298 corepages = totalpages - required_movablecore;
7300 required_kernelcore = max(required_kernelcore, corepages);
7304 * If kernelcore was not specified or kernelcore size is larger
7305 * than totalpages, there is no ZONE_MOVABLE.
7307 if (!required_kernelcore || required_kernelcore >= totalpages)
7310 /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
7311 usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
7314 /* Spread kernelcore memory as evenly as possible throughout nodes */
7315 kernelcore_node = required_kernelcore / usable_nodes;
7316 for_each_node_state(nid, N_MEMORY) {
7317 unsigned long start_pfn, end_pfn;
7320 * Recalculate kernelcore_node if the division per node
7321 * now exceeds what is necessary to satisfy the requested
7322 * amount of memory for the kernel
7324 if (required_kernelcore < kernelcore_node)
7325 kernelcore_node = required_kernelcore / usable_nodes;
7328 * As the map is walked, we track how much memory is usable
7329 * by the kernel using kernelcore_remaining. When it is
7330 * 0, the rest of the node is usable by ZONE_MOVABLE
7332 kernelcore_remaining = kernelcore_node;
7334 /* Go through each range of PFNs within this node */
7335 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
7336 unsigned long size_pages;
7338 start_pfn = max(start_pfn, zone_movable_pfn[nid]);
7339 if (start_pfn >= end_pfn)
7342 /* Account for what is only usable for kernelcore */
7343 if (start_pfn < usable_startpfn) {
7344 unsigned long kernel_pages;
7345 kernel_pages = min(end_pfn, usable_startpfn)
7348 kernelcore_remaining -= min(kernel_pages,
7349 kernelcore_remaining);
7350 required_kernelcore -= min(kernel_pages,
7351 required_kernelcore);
7353 /* Continue if range is now fully accounted */
7354 if (end_pfn <= usable_startpfn) {
7357 * Push zone_movable_pfn to the end so
7358 * that if we have to rebalance
7359 * kernelcore across nodes, we will
7360 * not double account here
7362 zone_movable_pfn[nid] = end_pfn;
7365 start_pfn = usable_startpfn;
7369 * The usable PFN range for ZONE_MOVABLE is from
7370 * start_pfn->end_pfn. Calculate size_pages as the
7371 * number of pages used as kernelcore
7373 size_pages = end_pfn - start_pfn;
7374 if (size_pages > kernelcore_remaining)
7375 size_pages = kernelcore_remaining;
7376 zone_movable_pfn[nid] = start_pfn + size_pages;
7379 * Some kernelcore has been met, update counts and
7380 * break if the kernelcore for this node has been
7383 required_kernelcore -= min(required_kernelcore,
7385 kernelcore_remaining -= size_pages;
7386 if (!kernelcore_remaining)
7392 * If there is still required_kernelcore, we do another pass with one
7393 * less node in the count. This will push zone_movable_pfn[nid] further
7394 * along on the nodes that still have memory until kernelcore is
7398 if (usable_nodes && required_kernelcore > usable_nodes)
7402 /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
7403 for (nid = 0; nid < MAX_NUMNODES; nid++)
7404 zone_movable_pfn[nid] =
7405 roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
7408 /* restore the node_state */
7409 node_states[N_MEMORY] = saved_node_state;
7412 /* Any regular or high memory on that node ? */
7413 static void check_for_memory(pg_data_t *pgdat, int nid)
7415 enum zone_type zone_type;
7417 for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
7418 struct zone *zone = &pgdat->node_zones[zone_type];
7419 if (populated_zone(zone)) {
7420 if (IS_ENABLED(CONFIG_HIGHMEM))
7421 node_set_state(nid, N_HIGH_MEMORY);
7422 if (zone_type <= ZONE_NORMAL)
7423 node_set_state(nid, N_NORMAL_MEMORY);
7430 * Some architecturs, e.g. ARC may have ZONE_HIGHMEM below ZONE_NORMAL. For
7431 * such cases we allow max_zone_pfn sorted in the descending order
7433 bool __weak arch_has_descending_max_zone_pfns(void)
7439 * free_area_init - Initialise all pg_data_t and zone data
7440 * @max_zone_pfn: an array of max PFNs for each zone
7442 * This will call free_area_init_node() for each active node in the system.
7443 * Using the page ranges provided by memblock_set_node(), the size of each
7444 * zone in each node and their holes is calculated. If the maximum PFN
7445 * between two adjacent zones match, it is assumed that the zone is empty.
7446 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
7447 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
7448 * starts where the previous one ended. For example, ZONE_DMA32 starts
7449 * at arch_max_dma_pfn.
7451 void __init free_area_init(unsigned long *max_zone_pfn)
7453 unsigned long start_pfn, end_pfn;
7457 /* Record where the zone boundaries are */
7458 memset(arch_zone_lowest_possible_pfn, 0,
7459 sizeof(arch_zone_lowest_possible_pfn));
7460 memset(arch_zone_highest_possible_pfn, 0,
7461 sizeof(arch_zone_highest_possible_pfn));
7463 start_pfn = find_min_pfn_with_active_regions();
7464 descending = arch_has_descending_max_zone_pfns();
7466 for (i = 0; i < MAX_NR_ZONES; i++) {
7468 zone = MAX_NR_ZONES - i - 1;
7472 if (zone == ZONE_MOVABLE)
7475 end_pfn = max(max_zone_pfn[zone], start_pfn);
7476 arch_zone_lowest_possible_pfn[zone] = start_pfn;
7477 arch_zone_highest_possible_pfn[zone] = end_pfn;
7479 start_pfn = end_pfn;
7482 /* Find the PFNs that ZONE_MOVABLE begins at in each node */
7483 memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
7484 find_zone_movable_pfns_for_nodes();
7486 /* Print out the zone ranges */
7487 pr_info("Zone ranges:\n");
7488 for (i = 0; i < MAX_NR_ZONES; i++) {
7489 if (i == ZONE_MOVABLE)
7491 pr_info(" %-8s ", zone_names[i]);
7492 if (arch_zone_lowest_possible_pfn[i] ==
7493 arch_zone_highest_possible_pfn[i])
7496 pr_cont("[mem %#018Lx-%#018Lx]\n",
7497 (u64)arch_zone_lowest_possible_pfn[i]
7499 ((u64)arch_zone_highest_possible_pfn[i]
7500 << PAGE_SHIFT) - 1);
7503 /* Print out the PFNs ZONE_MOVABLE begins at in each node */
7504 pr_info("Movable zone start for each node\n");
7505 for (i = 0; i < MAX_NUMNODES; i++) {
7506 if (zone_movable_pfn[i])
7507 pr_info(" Node %d: %#018Lx\n", i,
7508 (u64)zone_movable_pfn[i] << PAGE_SHIFT);
7512 * Print out the early node map, and initialize the
7513 * subsection-map relative to active online memory ranges to
7514 * enable future "sub-section" extensions of the memory map.
7516 pr_info("Early memory node ranges\n");
7517 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
7518 pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid,
7519 (u64)start_pfn << PAGE_SHIFT,
7520 ((u64)end_pfn << PAGE_SHIFT) - 1);
7521 subsection_map_init(start_pfn, end_pfn - start_pfn);
7524 /* Initialise every node */
7525 mminit_verify_pageflags_layout();
7526 setup_nr_node_ids();
7527 for_each_online_node(nid) {
7528 pg_data_t *pgdat = NODE_DATA(nid);
7529 free_area_init_node(nid);
7531 /* Any memory on that node */
7532 if (pgdat->node_present_pages)
7533 node_set_state(nid, N_MEMORY);
7534 check_for_memory(pgdat, nid);
7540 static int __init cmdline_parse_core(char *p, unsigned long *core,
7541 unsigned long *percent)
7543 unsigned long long coremem;
7549 /* Value may be a percentage of total memory, otherwise bytes */
7550 coremem = simple_strtoull(p, &endptr, 0);
7551 if (*endptr == '%') {
7552 /* Paranoid check for percent values greater than 100 */
7553 WARN_ON(coremem > 100);
7557 coremem = memparse(p, &p);
7558 /* Paranoid check that UL is enough for the coremem value */
7559 WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
7561 *core = coremem >> PAGE_SHIFT;
7568 * kernelcore=size sets the amount of memory for use for allocations that
7569 * cannot be reclaimed or migrated.
7571 static int __init cmdline_parse_kernelcore(char *p)
7573 /* parse kernelcore=mirror */
7574 if (parse_option_str(p, "mirror")) {
7575 mirrored_kernelcore = true;
7579 return cmdline_parse_core(p, &required_kernelcore,
7580 &required_kernelcore_percent);
7584 * movablecore=size sets the amount of memory for use for allocations that
7585 * can be reclaimed or migrated.
7587 static int __init cmdline_parse_movablecore(char *p)
7589 return cmdline_parse_core(p, &required_movablecore,
7590 &required_movablecore_percent);
7593 early_param("kernelcore", cmdline_parse_kernelcore);
7594 early_param("movablecore", cmdline_parse_movablecore);
7596 void adjust_managed_page_count(struct page *page, long count)
7598 atomic_long_add(count, &page_zone(page)->managed_pages);
7599 totalram_pages_add(count);
7600 #ifdef CONFIG_HIGHMEM
7601 if (PageHighMem(page))
7602 totalhigh_pages_add(count);
7605 EXPORT_SYMBOL(adjust_managed_page_count);
7607 unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
7610 unsigned long pages = 0;
7612 start = (void *)PAGE_ALIGN((unsigned long)start);
7613 end = (void *)((unsigned long)end & PAGE_MASK);
7614 for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
7615 struct page *page = virt_to_page(pos);
7616 void *direct_map_addr;
7619 * 'direct_map_addr' might be different from 'pos'
7620 * because some architectures' virt_to_page()
7621 * work with aliases. Getting the direct map
7622 * address ensures that we get a _writeable_
7623 * alias for the memset().
7625 direct_map_addr = page_address(page);
7626 if ((unsigned int)poison <= 0xFF)
7627 memset(direct_map_addr, poison, PAGE_SIZE);
7629 free_reserved_page(page);
7633 pr_info("Freeing %s memory: %ldK\n",
7634 s, pages << (PAGE_SHIFT - 10));
7639 #ifdef CONFIG_HIGHMEM
7640 void free_highmem_page(struct page *page)
7642 __free_reserved_page(page);
7643 totalram_pages_inc();
7644 atomic_long_inc(&page_zone(page)->managed_pages);
7645 totalhigh_pages_inc();
7650 void __init mem_init_print_info(const char *str)
7652 unsigned long physpages, codesize, datasize, rosize, bss_size;
7653 unsigned long init_code_size, init_data_size;
7655 physpages = get_num_physpages();
7656 codesize = _etext - _stext;
7657 datasize = _edata - _sdata;
7658 rosize = __end_rodata - __start_rodata;
7659 bss_size = __bss_stop - __bss_start;
7660 init_data_size = __init_end - __init_begin;
7661 init_code_size = _einittext - _sinittext;
7664 * Detect special cases and adjust section sizes accordingly:
7665 * 1) .init.* may be embedded into .data sections
7666 * 2) .init.text.* may be out of [__init_begin, __init_end],
7667 * please refer to arch/tile/kernel/vmlinux.lds.S.
7668 * 3) .rodata.* may be embedded into .text or .data sections.
7670 #define adj_init_size(start, end, size, pos, adj) \
7672 if (start <= pos && pos < end && size > adj) \
7676 adj_init_size(__init_begin, __init_end, init_data_size,
7677 _sinittext, init_code_size);
7678 adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
7679 adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
7680 adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
7681 adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
7683 #undef adj_init_size
7685 pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
7686 #ifdef CONFIG_HIGHMEM
7690 nr_free_pages() << (PAGE_SHIFT - 10),
7691 physpages << (PAGE_SHIFT - 10),
7692 codesize >> 10, datasize >> 10, rosize >> 10,
7693 (init_data_size + init_code_size) >> 10, bss_size >> 10,
7694 (physpages - totalram_pages() - totalcma_pages) << (PAGE_SHIFT - 10),
7695 totalcma_pages << (PAGE_SHIFT - 10),
7696 #ifdef CONFIG_HIGHMEM
7697 totalhigh_pages() << (PAGE_SHIFT - 10),
7699 str ? ", " : "", str ? str : "");
7703 * set_dma_reserve - set the specified number of pages reserved in the first zone
7704 * @new_dma_reserve: The number of pages to mark reserved
7706 * The per-cpu batchsize and zone watermarks are determined by managed_pages.
7707 * In the DMA zone, a significant percentage may be consumed by kernel image
7708 * and other unfreeable allocations which can skew the watermarks badly. This
7709 * function may optionally be used to account for unfreeable pages in the
7710 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
7711 * smaller per-cpu batchsize.
7713 void __init set_dma_reserve(unsigned long new_dma_reserve)
7715 dma_reserve = new_dma_reserve;
7718 static int page_alloc_cpu_dead(unsigned int cpu)
7721 lru_add_drain_cpu(cpu);
7725 * Spill the event counters of the dead processor
7726 * into the current processors event counters.
7727 * This artificially elevates the count of the current
7730 vm_events_fold_cpu(cpu);
7733 * Zero the differential counters of the dead processor
7734 * so that the vm statistics are consistent.
7736 * This is only okay since the processor is dead and cannot
7737 * race with what we are doing.
7739 cpu_vm_stats_fold(cpu);
7744 int hashdist = HASHDIST_DEFAULT;
7746 static int __init set_hashdist(char *str)
7750 hashdist = simple_strtoul(str, &str, 0);
7753 __setup("hashdist=", set_hashdist);
7756 void __init page_alloc_init(void)
7761 if (num_node_state(N_MEMORY) == 1)
7765 ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC_DEAD,
7766 "mm/page_alloc:dead", NULL,
7767 page_alloc_cpu_dead);
7772 * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio
7773 * or min_free_kbytes changes.
7775 static void calculate_totalreserve_pages(void)
7777 struct pglist_data *pgdat;
7778 unsigned long reserve_pages = 0;
7779 enum zone_type i, j;
7781 for_each_online_pgdat(pgdat) {
7783 pgdat->totalreserve_pages = 0;
7785 for (i = 0; i < MAX_NR_ZONES; i++) {
7786 struct zone *zone = pgdat->node_zones + i;
7788 unsigned long managed_pages = zone_managed_pages(zone);
7790 /* Find valid and maximum lowmem_reserve in the zone */
7791 for (j = i; j < MAX_NR_ZONES; j++) {
7792 if (zone->lowmem_reserve[j] > max)
7793 max = zone->lowmem_reserve[j];
7796 /* we treat the high watermark as reserved pages. */
7797 max += high_wmark_pages(zone);
7799 if (max > managed_pages)
7800 max = managed_pages;
7802 pgdat->totalreserve_pages += max;
7804 reserve_pages += max;
7807 totalreserve_pages = reserve_pages;
7811 * setup_per_zone_lowmem_reserve - called whenever
7812 * sysctl_lowmem_reserve_ratio changes. Ensures that each zone
7813 * has a correct pages reserved value, so an adequate number of
7814 * pages are left in the zone after a successful __alloc_pages().
7816 static void setup_per_zone_lowmem_reserve(void)
7818 struct pglist_data *pgdat;
7819 enum zone_type i, j;
7821 for_each_online_pgdat(pgdat) {
7822 for (i = 0; i < MAX_NR_ZONES - 1; i++) {
7823 struct zone *zone = &pgdat->node_zones[i];
7824 int ratio = sysctl_lowmem_reserve_ratio[i];
7825 bool clear = !ratio || !zone_managed_pages(zone);
7826 unsigned long managed_pages = 0;
7828 for (j = i + 1; j < MAX_NR_ZONES; j++) {
7829 struct zone *upper_zone = &pgdat->node_zones[j];
7831 managed_pages += zone_managed_pages(upper_zone);
7834 zone->lowmem_reserve[j] = 0;
7836 zone->lowmem_reserve[j] = managed_pages / ratio;
7841 /* update totalreserve_pages */
7842 calculate_totalreserve_pages();
7845 static void __setup_per_zone_wmarks(void)
7847 unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
7848 unsigned long lowmem_pages = 0;
7850 unsigned long flags;
7852 /* Calculate total number of !ZONE_HIGHMEM pages */
7853 for_each_zone(zone) {
7854 if (!is_highmem(zone))
7855 lowmem_pages += zone_managed_pages(zone);
7858 for_each_zone(zone) {
7861 spin_lock_irqsave(&zone->lock, flags);
7862 tmp = (u64)pages_min * zone_managed_pages(zone);
7863 do_div(tmp, lowmem_pages);
7864 if (is_highmem(zone)) {
7866 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
7867 * need highmem pages, so cap pages_min to a small
7870 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
7871 * deltas control async page reclaim, and so should
7872 * not be capped for highmem.
7874 unsigned long min_pages;
7876 min_pages = zone_managed_pages(zone) / 1024;
7877 min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
7878 zone->_watermark[WMARK_MIN] = min_pages;
7881 * If it's a lowmem zone, reserve a number of pages
7882 * proportionate to the zone's size.
7884 zone->_watermark[WMARK_MIN] = tmp;
7888 * Set the kswapd watermarks distance according to the
7889 * scale factor in proportion to available memory, but
7890 * ensure a minimum size on small systems.
7892 tmp = max_t(u64, tmp >> 2,
7893 mult_frac(zone_managed_pages(zone),
7894 watermark_scale_factor, 10000));
7896 zone->watermark_boost = 0;
7897 zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp;
7898 zone->_watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;
7900 spin_unlock_irqrestore(&zone->lock, flags);
7903 /* update totalreserve_pages */
7904 calculate_totalreserve_pages();
7908 * setup_per_zone_wmarks - called when min_free_kbytes changes
7909 * or when memory is hot-{added|removed}
7911 * Ensures that the watermark[min,low,high] values for each zone are set
7912 * correctly with respect to min_free_kbytes.
7914 void setup_per_zone_wmarks(void)
7916 static DEFINE_SPINLOCK(lock);
7919 __setup_per_zone_wmarks();
7924 * Initialise min_free_kbytes.
7926 * For small machines we want it small (128k min). For large machines
7927 * we want it large (256MB max). But it is not linear, because network
7928 * bandwidth does not increase linearly with machine size. We use
7930 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
7931 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
7947 int __meminit init_per_zone_wmark_min(void)
7949 unsigned long lowmem_kbytes;
7950 int new_min_free_kbytes;
7952 lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
7953 new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
7955 if (new_min_free_kbytes > user_min_free_kbytes) {
7956 min_free_kbytes = new_min_free_kbytes;
7957 if (min_free_kbytes < 128)
7958 min_free_kbytes = 128;
7959 if (min_free_kbytes > 262144)
7960 min_free_kbytes = 262144;
7962 pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
7963 new_min_free_kbytes, user_min_free_kbytes);
7965 setup_per_zone_wmarks();
7966 refresh_zone_stat_thresholds();
7967 setup_per_zone_lowmem_reserve();
7970 setup_min_unmapped_ratio();
7971 setup_min_slab_ratio();
7974 khugepaged_min_free_kbytes_update();
7978 postcore_initcall(init_per_zone_wmark_min)
7981 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
7982 * that we can call two helper functions whenever min_free_kbytes
7985 int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
7986 void *buffer, size_t *length, loff_t *ppos)
7990 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7995 user_min_free_kbytes = min_free_kbytes;
7996 setup_per_zone_wmarks();
8001 int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
8002 void *buffer, size_t *length, loff_t *ppos)
8006 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
8011 setup_per_zone_wmarks();
8017 static void setup_min_unmapped_ratio(void)
8022 for_each_online_pgdat(pgdat)
8023 pgdat->min_unmapped_pages = 0;
8026 zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) *
8027 sysctl_min_unmapped_ratio) / 100;
8031 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
8032 void *buffer, size_t *length, loff_t *ppos)
8036 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
8040 setup_min_unmapped_ratio();
8045 static void setup_min_slab_ratio(void)
8050 for_each_online_pgdat(pgdat)
8051 pgdat->min_slab_pages = 0;
8054 zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) *
8055 sysctl_min_slab_ratio) / 100;
8058 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
8059 void *buffer, size_t *length, loff_t *ppos)
8063 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
8067 setup_min_slab_ratio();
8074 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
8075 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
8076 * whenever sysctl_lowmem_reserve_ratio changes.
8078 * The reserve ratio obviously has absolutely no relation with the
8079 * minimum watermarks. The lowmem reserve ratio can only make sense
8080 * if in function of the boot time zone sizes.
8082 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
8083 void *buffer, size_t *length, loff_t *ppos)
8087 proc_dointvec_minmax(table, write, buffer, length, ppos);
8089 for (i = 0; i < MAX_NR_ZONES; i++) {
8090 if (sysctl_lowmem_reserve_ratio[i] < 1)
8091 sysctl_lowmem_reserve_ratio[i] = 0;
8094 setup_per_zone_lowmem_reserve();
8098 static void __zone_pcp_update(struct zone *zone)
8102 for_each_possible_cpu(cpu)
8103 pageset_set_high_and_batch(zone,
8104 per_cpu_ptr(zone->pageset, cpu));
8108 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
8109 * cpu. It is the fraction of total pages in each zone that a hot per cpu
8110 * pagelist can have before it gets flushed back to buddy allocator.
8112 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write,
8113 void *buffer, size_t *length, loff_t *ppos)
8116 int old_percpu_pagelist_fraction;
8119 mutex_lock(&pcp_batch_high_lock);
8120 old_percpu_pagelist_fraction = percpu_pagelist_fraction;
8122 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
8123 if (!write || ret < 0)
8126 /* Sanity checking to avoid pcp imbalance */
8127 if (percpu_pagelist_fraction &&
8128 percpu_pagelist_fraction < MIN_PERCPU_PAGELIST_FRACTION) {
8129 percpu_pagelist_fraction = old_percpu_pagelist_fraction;
8135 if (percpu_pagelist_fraction == old_percpu_pagelist_fraction)
8138 for_each_populated_zone(zone)
8139 __zone_pcp_update(zone);
8141 mutex_unlock(&pcp_batch_high_lock);
8145 #ifndef __HAVE_ARCH_RESERVED_KERNEL_PAGES
8147 * Returns the number of pages that arch has reserved but
8148 * is not known to alloc_large_system_hash().
8150 static unsigned long __init arch_reserved_kernel_pages(void)
8157 * Adaptive scale is meant to reduce sizes of hash tables on large memory
8158 * machines. As memory size is increased the scale is also increased but at
8159 * slower pace. Starting from ADAPT_SCALE_BASE (64G), every time memory
8160 * quadruples the scale is increased by one, which means the size of hash table
8161 * only doubles, instead of quadrupling as well.
8162 * Because 32-bit systems cannot have large physical memory, where this scaling
8163 * makes sense, it is disabled on such platforms.
8165 #if __BITS_PER_LONG > 32
8166 #define ADAPT_SCALE_BASE (64ul << 30)
8167 #define ADAPT_SCALE_SHIFT 2
8168 #define ADAPT_SCALE_NPAGES (ADAPT_SCALE_BASE >> PAGE_SHIFT)
8172 * allocate a large system hash table from bootmem
8173 * - it is assumed that the hash table must contain an exact power-of-2
8174 * quantity of entries
8175 * - limit is the number of hash buckets, not the total allocation size
8177 void *__init alloc_large_system_hash(const char *tablename,
8178 unsigned long bucketsize,
8179 unsigned long numentries,
8182 unsigned int *_hash_shift,
8183 unsigned int *_hash_mask,
8184 unsigned long low_limit,
8185 unsigned long high_limit)
8187 unsigned long long max = high_limit;
8188 unsigned long log2qty, size;
8193 /* allow the kernel cmdline to have a say */
8195 /* round applicable memory size up to nearest megabyte */
8196 numentries = nr_kernel_pages;
8197 numentries -= arch_reserved_kernel_pages();
8199 /* It isn't necessary when PAGE_SIZE >= 1MB */
8200 if (PAGE_SHIFT < 20)
8201 numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
8203 #if __BITS_PER_LONG > 32
8205 unsigned long adapt;
8207 for (adapt = ADAPT_SCALE_NPAGES; adapt < numentries;
8208 adapt <<= ADAPT_SCALE_SHIFT)
8213 /* limit to 1 bucket per 2^scale bytes of low memory */
8214 if (scale > PAGE_SHIFT)
8215 numentries >>= (scale - PAGE_SHIFT);
8217 numentries <<= (PAGE_SHIFT - scale);
8219 /* Make sure we've got at least a 0-order allocation.. */
8220 if (unlikely(flags & HASH_SMALL)) {
8221 /* Makes no sense without HASH_EARLY */
8222 WARN_ON(!(flags & HASH_EARLY));
8223 if (!(numentries >> *_hash_shift)) {
8224 numentries = 1UL << *_hash_shift;
8225 BUG_ON(!numentries);
8227 } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
8228 numentries = PAGE_SIZE / bucketsize;
8230 numentries = roundup_pow_of_two(numentries);
8232 /* limit allocation size to 1/16 total memory by default */
8234 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
8235 do_div(max, bucketsize);
8237 max = min(max, 0x80000000ULL);
8239 if (numentries < low_limit)
8240 numentries = low_limit;
8241 if (numentries > max)
8244 log2qty = ilog2(numentries);
8246 gfp_flags = (flags & HASH_ZERO) ? GFP_ATOMIC | __GFP_ZERO : GFP_ATOMIC;
8249 size = bucketsize << log2qty;
8250 if (flags & HASH_EARLY) {
8251 if (flags & HASH_ZERO)
8252 table = memblock_alloc(size, SMP_CACHE_BYTES);
8254 table = memblock_alloc_raw(size,
8256 } else if (get_order(size) >= MAX_ORDER || hashdist) {
8257 table = __vmalloc(size, gfp_flags);
8261 * If bucketsize is not a power-of-two, we may free
8262 * some pages at the end of hash table which
8263 * alloc_pages_exact() automatically does
8265 table = alloc_pages_exact(size, gfp_flags);
8266 kmemleak_alloc(table, size, 1, gfp_flags);
8268 } while (!table && size > PAGE_SIZE && --log2qty);
8271 panic("Failed to allocate %s hash table\n", tablename);
8273 pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
8274 tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
8275 virt ? "vmalloc" : "linear");
8278 *_hash_shift = log2qty;
8280 *_hash_mask = (1 << log2qty) - 1;
8286 * This function checks whether pageblock includes unmovable pages or not.
8288 * PageLRU check without isolation or lru_lock could race so that
8289 * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
8290 * check without lock_page also may miss some movable non-lru pages at
8291 * race condition. So you can't expect this function should be exact.
8293 * Returns a page without holding a reference. If the caller wants to
8294 * dereference that page (e.g., dumping), it has to make sure that it
8295 * cannot get removed (e.g., via memory unplug) concurrently.
8298 struct page *has_unmovable_pages(struct zone *zone, struct page *page,
8299 int migratetype, int flags)
8301 unsigned long iter = 0;
8302 unsigned long pfn = page_to_pfn(page);
8303 unsigned long offset = pfn % pageblock_nr_pages;
8305 if (is_migrate_cma_page(page)) {
8307 * CMA allocations (alloc_contig_range) really need to mark
8308 * isolate CMA pageblocks even when they are not movable in fact
8309 * so consider them movable here.
8311 if (is_migrate_cma(migratetype))
8317 for (; iter < pageblock_nr_pages - offset; iter++) {
8318 if (!pfn_valid_within(pfn + iter))
8321 page = pfn_to_page(pfn + iter);
8324 * Both, bootmem allocations and memory holes are marked
8325 * PG_reserved and are unmovable. We can even have unmovable
8326 * allocations inside ZONE_MOVABLE, for example when
8327 * specifying "movablecore".
8329 if (PageReserved(page))
8333 * If the zone is movable and we have ruled out all reserved
8334 * pages then it should be reasonably safe to assume the rest
8337 if (zone_idx(zone) == ZONE_MOVABLE)
8341 * Hugepages are not in LRU lists, but they're movable.
8342 * THPs are on the LRU, but need to be counted as #small pages.
8343 * We need not scan over tail pages because we don't
8344 * handle each tail page individually in migration.
8346 if (PageHuge(page) || PageTransCompound(page)) {
8347 struct page *head = compound_head(page);
8348 unsigned int skip_pages;
8350 if (PageHuge(page)) {
8351 if (!hugepage_migration_supported(page_hstate(head)))
8353 } else if (!PageLRU(head) && !__PageMovable(head)) {
8357 skip_pages = compound_nr(head) - (page - head);
8358 iter += skip_pages - 1;
8363 * We can't use page_count without pin a page
8364 * because another CPU can free compound page.
8365 * This check already skips compound tails of THP
8366 * because their page->_refcount is zero at all time.
8368 if (!page_ref_count(page)) {
8369 if (PageBuddy(page))
8370 iter += (1 << buddy_order(page)) - 1;
8375 * The HWPoisoned page may be not in buddy system, and
8376 * page_count() is not 0.
8378 if ((flags & MEMORY_OFFLINE) && PageHWPoison(page))
8382 * We treat all PageOffline() pages as movable when offlining
8383 * to give drivers a chance to decrement their reference count
8384 * in MEM_GOING_OFFLINE in order to indicate that these pages
8385 * can be offlined as there are no direct references anymore.
8386 * For actually unmovable PageOffline() where the driver does
8387 * not support this, we will fail later when trying to actually
8388 * move these pages that still have a reference count > 0.
8389 * (false negatives in this function only)
8391 if ((flags & MEMORY_OFFLINE) && PageOffline(page))
8394 if (__PageMovable(page) || PageLRU(page))
8398 * If there are RECLAIMABLE pages, we need to check
8399 * it. But now, memory offline itself doesn't call
8400 * shrink_node_slabs() and it still to be fixed.
8407 #ifdef CONFIG_CONTIG_ALLOC
8408 static unsigned long pfn_max_align_down(unsigned long pfn)
8410 return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
8411 pageblock_nr_pages) - 1);
8414 static unsigned long pfn_max_align_up(unsigned long pfn)
8416 return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
8417 pageblock_nr_pages));
8420 /* [start, end) must belong to a single zone. */
8421 static int __alloc_contig_migrate_range(struct compact_control *cc,
8422 unsigned long start, unsigned long end)
8424 /* This function is based on compact_zone() from compaction.c. */
8425 unsigned int nr_reclaimed;
8426 unsigned long pfn = start;
8427 unsigned int tries = 0;
8429 struct migration_target_control mtc = {
8430 .nid = zone_to_nid(cc->zone),
8431 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
8436 while (pfn < end || !list_empty(&cc->migratepages)) {
8437 if (fatal_signal_pending(current)) {
8442 if (list_empty(&cc->migratepages)) {
8443 cc->nr_migratepages = 0;
8444 pfn = isolate_migratepages_range(cc, pfn, end);
8450 } else if (++tries == 5) {
8451 ret = ret < 0 ? ret : -EBUSY;
8455 nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
8457 cc->nr_migratepages -= nr_reclaimed;
8459 ret = migrate_pages(&cc->migratepages, alloc_migration_target,
8460 NULL, (unsigned long)&mtc, cc->mode, MR_CONTIG_RANGE);
8463 putback_movable_pages(&cc->migratepages);
8470 * alloc_contig_range() -- tries to allocate given range of pages
8471 * @start: start PFN to allocate
8472 * @end: one-past-the-last PFN to allocate
8473 * @migratetype: migratetype of the underlaying pageblocks (either
8474 * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks
8475 * in range must have the same migratetype and it must
8476 * be either of the two.
8477 * @gfp_mask: GFP mask to use during compaction
8479 * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
8480 * aligned. The PFN range must belong to a single zone.
8482 * The first thing this routine does is attempt to MIGRATE_ISOLATE all
8483 * pageblocks in the range. Once isolated, the pageblocks should not
8484 * be modified by others.
8486 * Return: zero on success or negative error code. On success all
8487 * pages which PFN is in [start, end) are allocated for the caller and
8488 * need to be freed with free_contig_range().
8490 int alloc_contig_range(unsigned long start, unsigned long end,
8491 unsigned migratetype, gfp_t gfp_mask)
8493 unsigned long outer_start, outer_end;
8497 struct compact_control cc = {
8498 .nr_migratepages = 0,
8500 .zone = page_zone(pfn_to_page(start)),
8501 .mode = MIGRATE_SYNC,
8502 .ignore_skip_hint = true,
8503 .no_set_skip_hint = true,
8504 .gfp_mask = current_gfp_context(gfp_mask),
8505 .alloc_contig = true,
8507 INIT_LIST_HEAD(&cc.migratepages);
8510 * What we do here is we mark all pageblocks in range as
8511 * MIGRATE_ISOLATE. Because pageblock and max order pages may
8512 * have different sizes, and due to the way page allocator
8513 * work, we align the range to biggest of the two pages so
8514 * that page allocator won't try to merge buddies from
8515 * different pageblocks and change MIGRATE_ISOLATE to some
8516 * other migration type.
8518 * Once the pageblocks are marked as MIGRATE_ISOLATE, we
8519 * migrate the pages from an unaligned range (ie. pages that
8520 * we are interested in). This will put all the pages in
8521 * range back to page allocator as MIGRATE_ISOLATE.
8523 * When this is done, we take the pages in range from page
8524 * allocator removing them from the buddy system. This way
8525 * page allocator will never consider using them.
8527 * This lets us mark the pageblocks back as
8528 * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
8529 * aligned range but not in the unaligned, original range are
8530 * put back to page allocator so that buddy can use them.
8533 ret = start_isolate_page_range(pfn_max_align_down(start),
8534 pfn_max_align_up(end), migratetype, 0);
8539 * In case of -EBUSY, we'd like to know which page causes problem.
8540 * So, just fall through. test_pages_isolated() has a tracepoint
8541 * which will report the busy page.
8543 * It is possible that busy pages could become available before
8544 * the call to test_pages_isolated, and the range will actually be
8545 * allocated. So, if we fall through be sure to clear ret so that
8546 * -EBUSY is not accidentally used or returned to caller.
8548 ret = __alloc_contig_migrate_range(&cc, start, end);
8549 if (ret && ret != -EBUSY)
8554 * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
8555 * aligned blocks that are marked as MIGRATE_ISOLATE. What's
8556 * more, all pages in [start, end) are free in page allocator.
8557 * What we are going to do is to allocate all pages from
8558 * [start, end) (that is remove them from page allocator).
8560 * The only problem is that pages at the beginning and at the
8561 * end of interesting range may be not aligned with pages that
8562 * page allocator holds, ie. they can be part of higher order
8563 * pages. Because of this, we reserve the bigger range and
8564 * once this is done free the pages we are not interested in.
8566 * We don't have to hold zone->lock here because the pages are
8567 * isolated thus they won't get removed from buddy.
8570 lru_add_drain_all();
8573 outer_start = start;
8574 while (!PageBuddy(pfn_to_page(outer_start))) {
8575 if (++order >= MAX_ORDER) {
8576 outer_start = start;
8579 outer_start &= ~0UL << order;
8582 if (outer_start != start) {
8583 order = buddy_order(pfn_to_page(outer_start));
8586 * outer_start page could be small order buddy page and
8587 * it doesn't include start page. Adjust outer_start
8588 * in this case to report failed page properly
8589 * on tracepoint in test_pages_isolated()
8591 if (outer_start + (1UL << order) <= start)
8592 outer_start = start;
8595 /* Make sure the range is really isolated. */
8596 if (test_pages_isolated(outer_start, end, 0)) {
8597 pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n",
8598 __func__, outer_start, end);
8603 /* Grab isolated pages from freelists. */
8604 outer_end = isolate_freepages_range(&cc, outer_start, end);
8610 /* Free head and tail (if any) */
8611 if (start != outer_start)
8612 free_contig_range(outer_start, start - outer_start);
8613 if (end != outer_end)
8614 free_contig_range(end, outer_end - end);
8617 undo_isolate_page_range(pfn_max_align_down(start),
8618 pfn_max_align_up(end), migratetype);
8621 EXPORT_SYMBOL(alloc_contig_range);
8623 static int __alloc_contig_pages(unsigned long start_pfn,
8624 unsigned long nr_pages, gfp_t gfp_mask)
8626 unsigned long end_pfn = start_pfn + nr_pages;
8628 return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
8632 static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
8633 unsigned long nr_pages)
8635 unsigned long i, end_pfn = start_pfn + nr_pages;
8638 for (i = start_pfn; i < end_pfn; i++) {
8639 page = pfn_to_online_page(i);
8643 if (page_zone(page) != z)
8646 if (PageReserved(page))
8649 if (page_count(page) > 0)
8658 static bool zone_spans_last_pfn(const struct zone *zone,
8659 unsigned long start_pfn, unsigned long nr_pages)
8661 unsigned long last_pfn = start_pfn + nr_pages - 1;
8663 return zone_spans_pfn(zone, last_pfn);
8667 * alloc_contig_pages() -- tries to find and allocate contiguous range of pages
8668 * @nr_pages: Number of contiguous pages to allocate
8669 * @gfp_mask: GFP mask to limit search and used during compaction
8671 * @nodemask: Mask for other possible nodes
8673 * This routine is a wrapper around alloc_contig_range(). It scans over zones
8674 * on an applicable zonelist to find a contiguous pfn range which can then be
8675 * tried for allocation with alloc_contig_range(). This routine is intended
8676 * for allocation requests which can not be fulfilled with the buddy allocator.
8678 * The allocated memory is always aligned to a page boundary. If nr_pages is a
8679 * power of two then the alignment is guaranteed to be to the given nr_pages
8680 * (e.g. 1GB request would be aligned to 1GB).
8682 * Allocated pages can be freed with free_contig_range() or by manually calling
8683 * __free_page() on each allocated page.
8685 * Return: pointer to contiguous pages on success, or NULL if not successful.
8687 struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask,
8688 int nid, nodemask_t *nodemask)
8690 unsigned long ret, pfn, flags;
8691 struct zonelist *zonelist;
8695 zonelist = node_zonelist(nid, gfp_mask);
8696 for_each_zone_zonelist_nodemask(zone, z, zonelist,
8697 gfp_zone(gfp_mask), nodemask) {
8698 spin_lock_irqsave(&zone->lock, flags);
8700 pfn = ALIGN(zone->zone_start_pfn, nr_pages);
8701 while (zone_spans_last_pfn(zone, pfn, nr_pages)) {
8702 if (pfn_range_valid_contig(zone, pfn, nr_pages)) {
8704 * We release the zone lock here because
8705 * alloc_contig_range() will also lock the zone
8706 * at some point. If there's an allocation
8707 * spinning on this lock, it may win the race
8708 * and cause alloc_contig_range() to fail...
8710 spin_unlock_irqrestore(&zone->lock, flags);
8711 ret = __alloc_contig_pages(pfn, nr_pages,
8714 return pfn_to_page(pfn);
8715 spin_lock_irqsave(&zone->lock, flags);
8719 spin_unlock_irqrestore(&zone->lock, flags);
8723 #endif /* CONFIG_CONTIG_ALLOC */
8725 void free_contig_range(unsigned long pfn, unsigned int nr_pages)
8727 unsigned int count = 0;
8729 for (; nr_pages--; pfn++) {
8730 struct page *page = pfn_to_page(pfn);
8732 count += page_count(page) != 1;
8735 WARN(count != 0, "%d pages are still in use!\n", count);
8737 EXPORT_SYMBOL(free_contig_range);
8740 * The zone indicated has a new number of managed_pages; batch sizes and percpu
8741 * page high values need to be recalulated.
8743 void __meminit zone_pcp_update(struct zone *zone)
8745 mutex_lock(&pcp_batch_high_lock);
8746 __zone_pcp_update(zone);
8747 mutex_unlock(&pcp_batch_high_lock);
8750 void zone_pcp_reset(struct zone *zone)
8752 unsigned long flags;
8754 struct per_cpu_pageset *pset;
8756 /* avoid races with drain_pages() */
8757 local_irq_save(flags);
8758 if (zone->pageset != &boot_pageset) {
8759 for_each_online_cpu(cpu) {
8760 pset = per_cpu_ptr(zone->pageset, cpu);
8761 drain_zonestat(zone, pset);
8763 free_percpu(zone->pageset);
8764 zone->pageset = &boot_pageset;
8766 local_irq_restore(flags);
8769 #ifdef CONFIG_MEMORY_HOTREMOVE
8771 * All pages in the range must be in a single zone, must not contain holes,
8772 * must span full sections, and must be isolated before calling this function.
8774 void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
8776 unsigned long pfn = start_pfn;
8780 unsigned long flags;
8782 offline_mem_sections(pfn, end_pfn);
8783 zone = page_zone(pfn_to_page(pfn));
8784 spin_lock_irqsave(&zone->lock, flags);
8785 while (pfn < end_pfn) {
8786 page = pfn_to_page(pfn);
8788 * The HWPoisoned page may be not in buddy system, and
8789 * page_count() is not 0.
8791 if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
8796 * At this point all remaining PageOffline() pages have a
8797 * reference count of 0 and can simply be skipped.
8799 if (PageOffline(page)) {
8800 BUG_ON(page_count(page));
8801 BUG_ON(PageBuddy(page));
8806 BUG_ON(page_count(page));
8807 BUG_ON(!PageBuddy(page));
8808 order = buddy_order(page);
8809 del_page_from_free_list(page, zone, order);
8810 pfn += (1 << order);
8812 spin_unlock_irqrestore(&zone->lock, flags);
8816 bool is_free_buddy_page(struct page *page)
8818 struct zone *zone = page_zone(page);
8819 unsigned long pfn = page_to_pfn(page);
8820 unsigned long flags;
8823 spin_lock_irqsave(&zone->lock, flags);
8824 for (order = 0; order < MAX_ORDER; order++) {
8825 struct page *page_head = page - (pfn & ((1 << order) - 1));
8827 if (PageBuddy(page_head) && buddy_order(page_head) >= order)
8830 spin_unlock_irqrestore(&zone->lock, flags);
8832 return order < MAX_ORDER;
8835 #ifdef CONFIG_MEMORY_FAILURE
8837 * Break down a higher-order page in sub-pages, and keep our target out of
8840 static void break_down_buddy_pages(struct zone *zone, struct page *page,
8841 struct page *target, int low, int high,
8844 unsigned long size = 1 << high;
8845 struct page *current_buddy, *next_page;
8847 while (high > low) {
8851 if (target >= &page[size]) {
8852 next_page = page + size;
8853 current_buddy = page;
8856 current_buddy = page + size;
8859 if (set_page_guard(zone, current_buddy, high, migratetype))
8862 if (current_buddy != target) {
8863 add_to_free_list(current_buddy, zone, high, migratetype);
8864 set_buddy_order(current_buddy, high);
8871 * Take a page that will be marked as poisoned off the buddy allocator.
8873 bool take_page_off_buddy(struct page *page)
8875 struct zone *zone = page_zone(page);
8876 unsigned long pfn = page_to_pfn(page);
8877 unsigned long flags;
8881 spin_lock_irqsave(&zone->lock, flags);
8882 for (order = 0; order < MAX_ORDER; order++) {
8883 struct page *page_head = page - (pfn & ((1 << order) - 1));
8884 int page_order = buddy_order(page_head);
8886 if (PageBuddy(page_head) && page_order >= order) {
8887 unsigned long pfn_head = page_to_pfn(page_head);
8888 int migratetype = get_pfnblock_migratetype(page_head,
8891 del_page_from_free_list(page_head, zone, page_order);
8892 break_down_buddy_pages(zone, page_head, page, 0,
8893 page_order, migratetype);
8894 if (!is_migrate_isolate(migratetype))
8895 __mod_zone_freepage_state(zone, -1, migratetype);
8899 if (page_count(page_head) > 0)
8902 spin_unlock_irqrestore(&zone->lock, flags);