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/swapops.h>
23 #include <linux/interrupt.h>
24 #include <linux/pagemap.h>
25 #include <linux/jiffies.h>
26 #include <linux/memblock.h>
27 #include <linux/compiler.h>
28 #include <linux/kernel.h>
29 #include <linux/kasan.h>
30 #include <linux/kmsan.h>
31 #include <linux/module.h>
32 #include <linux/suspend.h>
33 #include <linux/pagevec.h>
34 #include <linux/blkdev.h>
35 #include <linux/slab.h>
36 #include <linux/ratelimit.h>
37 #include <linux/oom.h>
38 #include <linux/topology.h>
39 #include <linux/sysctl.h>
40 #include <linux/cpu.h>
41 #include <linux/cpuset.h>
42 #include <linux/memory_hotplug.h>
43 #include <linux/nodemask.h>
44 #include <linux/vmalloc.h>
45 #include <linux/vmstat.h>
46 #include <linux/mempolicy.h>
47 #include <linux/memremap.h>
48 #include <linux/stop_machine.h>
49 #include <linux/random.h>
50 #include <linux/sort.h>
51 #include <linux/pfn.h>
52 #include <linux/backing-dev.h>
53 #include <linux/fault-inject.h>
54 #include <linux/page-isolation.h>
55 #include <linux/debugobjects.h>
56 #include <linux/kmemleak.h>
57 #include <linux/compaction.h>
58 #include <trace/events/kmem.h>
59 #include <trace/events/oom.h>
60 #include <linux/prefetch.h>
61 #include <linux/mm_inline.h>
62 #include <linux/mmu_notifier.h>
63 #include <linux/migrate.h>
64 #include <linux/hugetlb.h>
65 #include <linux/sched/rt.h>
66 #include <linux/sched/mm.h>
67 #include <linux/page_owner.h>
68 #include <linux/page_table_check.h>
69 #include <linux/kthread.h>
70 #include <linux/memcontrol.h>
71 #include <linux/ftrace.h>
72 #include <linux/lockdep.h>
73 #include <linux/nmi.h>
74 #include <linux/psi.h>
75 #include <linux/padata.h>
76 #include <linux/khugepaged.h>
77 #include <linux/buffer_head.h>
78 #include <linux/delayacct.h>
79 #include <asm/sections.h>
80 #include <asm/tlbflush.h>
81 #include <asm/div64.h>
84 #include "page_reporting.h"
87 /* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */
88 typedef int __bitwise fpi_t;
90 /* No special request */
91 #define FPI_NONE ((__force fpi_t)0)
94 * Skip free page reporting notification for the (possibly merged) page.
95 * This does not hinder free page reporting from grabbing the page,
96 * reporting it and marking it "reported" - it only skips notifying
97 * the free page reporting infrastructure about a newly freed page. For
98 * example, used when temporarily pulling a page from a freelist and
99 * putting it back unmodified.
101 #define FPI_SKIP_REPORT_NOTIFY ((__force fpi_t)BIT(0))
104 * Place the (possibly merged) page to the tail of the freelist. Will ignore
105 * page shuffling (relevant code - e.g., memory onlining - is expected to
106 * shuffle the whole zone).
108 * Note: No code should rely on this flag for correctness - it's purely
109 * to allow for optimizations when handing back either fresh pages
110 * (memory onlining) or untouched pages (page isolation, free page
113 #define FPI_TO_TAIL ((__force fpi_t)BIT(1))
116 * Don't poison memory with KASAN (only for the tag-based modes).
117 * During boot, all non-reserved memblock memory is exposed to page_alloc.
118 * Poisoning all that memory lengthens boot time, especially on systems with
119 * large amount of RAM. This flag is used to skip that poisoning.
120 * This is only done for the tag-based KASAN modes, as those are able to
121 * detect memory corruptions with the memory tags assigned by default.
122 * All memory allocated normally after boot gets poisoned as usual.
124 #define FPI_SKIP_KASAN_POISON ((__force fpi_t)BIT(2))
126 /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
127 static DEFINE_MUTEX(pcp_batch_high_lock);
128 #define MIN_PERCPU_PAGELIST_HIGH_FRACTION (8)
130 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
132 * On SMP, spin_trylock is sufficient protection.
133 * On PREEMPT_RT, spin_trylock is equivalent on both SMP and UP.
135 #define pcp_trylock_prepare(flags) do { } while (0)
136 #define pcp_trylock_finish(flag) do { } while (0)
139 /* UP spin_trylock always succeeds so disable IRQs to prevent re-entrancy. */
140 #define pcp_trylock_prepare(flags) local_irq_save(flags)
141 #define pcp_trylock_finish(flags) local_irq_restore(flags)
145 * Locking a pcp requires a PCP lookup followed by a spinlock. To avoid
146 * a migration causing the wrong PCP to be locked and remote memory being
147 * potentially allocated, pin the task to the CPU for the lookup+lock.
148 * preempt_disable is used on !RT because it is faster than migrate_disable.
149 * migrate_disable is used on RT because otherwise RT spinlock usage is
150 * interfered with and a high priority task cannot preempt the allocator.
152 #ifndef CONFIG_PREEMPT_RT
153 #define pcpu_task_pin() preempt_disable()
154 #define pcpu_task_unpin() preempt_enable()
156 #define pcpu_task_pin() migrate_disable()
157 #define pcpu_task_unpin() migrate_enable()
161 * Generic helper to lookup and a per-cpu variable with an embedded spinlock.
162 * Return value should be used with equivalent unlock helper.
164 #define pcpu_spin_lock(type, member, ptr) \
168 _ret = this_cpu_ptr(ptr); \
169 spin_lock(&_ret->member); \
173 #define pcpu_spin_trylock(type, member, ptr) \
177 _ret = this_cpu_ptr(ptr); \
178 if (!spin_trylock(&_ret->member)) { \
185 #define pcpu_spin_unlock(member, ptr) \
187 spin_unlock(&ptr->member); \
191 /* struct per_cpu_pages specific helpers. */
192 #define pcp_spin_lock(ptr) \
193 pcpu_spin_lock(struct per_cpu_pages, lock, ptr)
195 #define pcp_spin_trylock(ptr) \
196 pcpu_spin_trylock(struct per_cpu_pages, lock, ptr)
198 #define pcp_spin_unlock(ptr) \
199 pcpu_spin_unlock(lock, ptr)
201 #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
202 DEFINE_PER_CPU(int, numa_node);
203 EXPORT_PER_CPU_SYMBOL(numa_node);
206 DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key);
208 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
210 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
211 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
212 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
213 * defined in <linux/topology.h>.
215 DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */
216 EXPORT_PER_CPU_SYMBOL(_numa_mem_);
219 static DEFINE_MUTEX(pcpu_drain_mutex);
221 #ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
222 volatile unsigned long latent_entropy __latent_entropy;
223 EXPORT_SYMBOL(latent_entropy);
227 * Array of node states.
229 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
230 [N_POSSIBLE] = NODE_MASK_ALL,
231 [N_ONLINE] = { { [0] = 1UL } },
233 [N_NORMAL_MEMORY] = { { [0] = 1UL } },
234 #ifdef CONFIG_HIGHMEM
235 [N_HIGH_MEMORY] = { { [0] = 1UL } },
237 [N_MEMORY] = { { [0] = 1UL } },
238 [N_CPU] = { { [0] = 1UL } },
241 EXPORT_SYMBOL(node_states);
243 atomic_long_t _totalram_pages __read_mostly;
244 EXPORT_SYMBOL(_totalram_pages);
245 unsigned long totalreserve_pages __read_mostly;
246 unsigned long totalcma_pages __read_mostly;
248 int percpu_pagelist_high_fraction;
249 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
250 DEFINE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, init_on_alloc);
251 EXPORT_SYMBOL(init_on_alloc);
253 DEFINE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_FREE_DEFAULT_ON, init_on_free);
254 EXPORT_SYMBOL(init_on_free);
256 static bool _init_on_alloc_enabled_early __read_mostly
257 = IS_ENABLED(CONFIG_INIT_ON_ALLOC_DEFAULT_ON);
258 static int __init early_init_on_alloc(char *buf)
261 return kstrtobool(buf, &_init_on_alloc_enabled_early);
263 early_param("init_on_alloc", early_init_on_alloc);
265 static bool _init_on_free_enabled_early __read_mostly
266 = IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON);
267 static int __init early_init_on_free(char *buf)
269 return kstrtobool(buf, &_init_on_free_enabled_early);
271 early_param("init_on_free", early_init_on_free);
274 * A cached value of the page's pageblock's migratetype, used when the page is
275 * put on a pcplist. Used to avoid the pageblock migratetype lookup when
276 * freeing from pcplists in most cases, at the cost of possibly becoming stale.
277 * Also the migratetype set in the page does not necessarily match the pcplist
278 * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
279 * other index - this ensures that it will be put on the correct CMA freelist.
281 static inline int get_pcppage_migratetype(struct page *page)
286 static inline void set_pcppage_migratetype(struct page *page, int migratetype)
288 page->index = migratetype;
291 #ifdef CONFIG_PM_SLEEP
293 * The following functions are used by the suspend/hibernate code to temporarily
294 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
295 * while devices are suspended. To avoid races with the suspend/hibernate code,
296 * they should always be called with system_transition_mutex held
297 * (gfp_allowed_mask also should only be modified with system_transition_mutex
298 * held, unless the suspend/hibernate code is guaranteed not to run in parallel
299 * with that modification).
302 static gfp_t saved_gfp_mask;
304 void pm_restore_gfp_mask(void)
306 WARN_ON(!mutex_is_locked(&system_transition_mutex));
307 if (saved_gfp_mask) {
308 gfp_allowed_mask = saved_gfp_mask;
313 void pm_restrict_gfp_mask(void)
315 WARN_ON(!mutex_is_locked(&system_transition_mutex));
316 WARN_ON(saved_gfp_mask);
317 saved_gfp_mask = gfp_allowed_mask;
318 gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
321 bool pm_suspended_storage(void)
323 if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS))
327 #endif /* CONFIG_PM_SLEEP */
329 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
330 unsigned int pageblock_order __read_mostly;
333 static void __free_pages_ok(struct page *page, unsigned int order,
337 * results with 256, 32 in the lowmem_reserve sysctl:
338 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
339 * 1G machine -> (16M dma, 784M normal, 224M high)
340 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
341 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
342 * HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA
344 * TBD: should special case ZONE_DMA32 machines here - in those we normally
345 * don't need any ZONE_NORMAL reservation
347 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = {
348 #ifdef CONFIG_ZONE_DMA
351 #ifdef CONFIG_ZONE_DMA32
355 #ifdef CONFIG_HIGHMEM
361 static char * const zone_names[MAX_NR_ZONES] = {
362 #ifdef CONFIG_ZONE_DMA
365 #ifdef CONFIG_ZONE_DMA32
369 #ifdef CONFIG_HIGHMEM
373 #ifdef CONFIG_ZONE_DEVICE
378 const char * const migratetype_names[MIGRATE_TYPES] = {
386 #ifdef CONFIG_MEMORY_ISOLATION
391 compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = {
392 [NULL_COMPOUND_DTOR] = NULL,
393 [COMPOUND_PAGE_DTOR] = free_compound_page,
394 #ifdef CONFIG_HUGETLB_PAGE
395 [HUGETLB_PAGE_DTOR] = free_huge_page,
397 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
398 [TRANSHUGE_PAGE_DTOR] = free_transhuge_page,
402 int min_free_kbytes = 1024;
403 int user_min_free_kbytes = -1;
404 int watermark_boost_factor __read_mostly = 15000;
405 int watermark_scale_factor = 10;
407 static unsigned long nr_kernel_pages __initdata;
408 static unsigned long nr_all_pages __initdata;
409 static unsigned long dma_reserve __initdata;
411 static unsigned long arch_zone_lowest_possible_pfn[MAX_NR_ZONES] __initdata;
412 static unsigned long arch_zone_highest_possible_pfn[MAX_NR_ZONES] __initdata;
413 static unsigned long required_kernelcore __initdata;
414 static unsigned long required_kernelcore_percent __initdata;
415 static unsigned long required_movablecore __initdata;
416 static unsigned long required_movablecore_percent __initdata;
417 static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
418 bool mirrored_kernelcore __initdata_memblock;
420 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
422 EXPORT_SYMBOL(movable_zone);
425 unsigned int nr_node_ids __read_mostly = MAX_NUMNODES;
426 unsigned int nr_online_nodes __read_mostly = 1;
427 EXPORT_SYMBOL(nr_node_ids);
428 EXPORT_SYMBOL(nr_online_nodes);
431 int page_group_by_mobility_disabled __read_mostly;
433 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
435 * During boot we initialize deferred pages on-demand, as needed, but once
436 * page_alloc_init_late() has finished, the deferred pages are all initialized,
437 * and we can permanently disable that path.
439 static DEFINE_STATIC_KEY_TRUE(deferred_pages);
441 static inline bool deferred_pages_enabled(void)
443 return static_branch_unlikely(&deferred_pages);
446 /* Returns true if the struct page for the pfn is uninitialised */
447 static inline bool __meminit early_page_uninitialised(unsigned long pfn)
449 int nid = early_pfn_to_nid(pfn);
451 if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn)
458 * Returns true when the remaining initialisation should be deferred until
459 * later in the boot cycle when it can be parallelised.
461 static bool __meminit
462 defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
464 static unsigned long prev_end_pfn, nr_initialised;
466 if (early_page_ext_enabled())
469 * prev_end_pfn static that contains the end of previous zone
470 * No need to protect because called very early in boot before smp_init.
472 if (prev_end_pfn != end_pfn) {
473 prev_end_pfn = end_pfn;
477 /* Always populate low zones for address-constrained allocations */
478 if (end_pfn < pgdat_end_pfn(NODE_DATA(nid)))
481 if (NODE_DATA(nid)->first_deferred_pfn != ULONG_MAX)
484 * We start only with one section of pages, more pages are added as
485 * needed until the rest of deferred pages are initialized.
488 if ((nr_initialised > PAGES_PER_SECTION) &&
489 (pfn & (PAGES_PER_SECTION - 1)) == 0) {
490 NODE_DATA(nid)->first_deferred_pfn = pfn;
496 static inline bool deferred_pages_enabled(void)
501 static inline bool early_page_uninitialised(unsigned long pfn)
506 static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
512 /* Return a pointer to the bitmap storing bits affecting a block of pages */
513 static inline unsigned long *get_pageblock_bitmap(const struct page *page,
516 #ifdef CONFIG_SPARSEMEM
517 return section_to_usemap(__pfn_to_section(pfn));
519 return page_zone(page)->pageblock_flags;
520 #endif /* CONFIG_SPARSEMEM */
523 static inline int pfn_to_bitidx(const struct page *page, unsigned long pfn)
525 #ifdef CONFIG_SPARSEMEM
526 pfn &= (PAGES_PER_SECTION-1);
528 pfn = pfn - pageblock_start_pfn(page_zone(page)->zone_start_pfn);
529 #endif /* CONFIG_SPARSEMEM */
530 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
533 static __always_inline
534 unsigned long __get_pfnblock_flags_mask(const struct page *page,
538 unsigned long *bitmap;
539 unsigned long bitidx, word_bitidx;
542 bitmap = get_pageblock_bitmap(page, pfn);
543 bitidx = pfn_to_bitidx(page, pfn);
544 word_bitidx = bitidx / BITS_PER_LONG;
545 bitidx &= (BITS_PER_LONG-1);
547 * This races, without locks, with set_pfnblock_flags_mask(). Ensure
548 * a consistent read of the memory array, so that results, even though
549 * racy, are not corrupted.
551 word = READ_ONCE(bitmap[word_bitidx]);
552 return (word >> bitidx) & mask;
556 * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
557 * @page: The page within the block of interest
558 * @pfn: The target page frame number
559 * @mask: mask of bits that the caller is interested in
561 * Return: pageblock_bits flags
563 unsigned long get_pfnblock_flags_mask(const struct page *page,
564 unsigned long pfn, unsigned long mask)
566 return __get_pfnblock_flags_mask(page, pfn, mask);
569 static __always_inline int get_pfnblock_migratetype(const struct page *page,
572 return __get_pfnblock_flags_mask(page, pfn, MIGRATETYPE_MASK);
576 * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
577 * @page: The page within the block of interest
578 * @flags: The flags to set
579 * @pfn: The target page frame number
580 * @mask: mask of bits that the caller is interested in
582 void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
586 unsigned long *bitmap;
587 unsigned long bitidx, word_bitidx;
590 BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
591 BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits));
593 bitmap = get_pageblock_bitmap(page, pfn);
594 bitidx = pfn_to_bitidx(page, pfn);
595 word_bitidx = bitidx / BITS_PER_LONG;
596 bitidx &= (BITS_PER_LONG-1);
598 VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
603 word = READ_ONCE(bitmap[word_bitidx]);
605 } while (!try_cmpxchg(&bitmap[word_bitidx], &word, (word & ~mask) | flags));
608 void set_pageblock_migratetype(struct page *page, int migratetype)
610 if (unlikely(page_group_by_mobility_disabled &&
611 migratetype < MIGRATE_PCPTYPES))
612 migratetype = MIGRATE_UNMOVABLE;
614 set_pfnblock_flags_mask(page, (unsigned long)migratetype,
615 page_to_pfn(page), MIGRATETYPE_MASK);
618 #ifdef CONFIG_DEBUG_VM
619 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
623 unsigned long pfn = page_to_pfn(page);
624 unsigned long sp, start_pfn;
627 seq = zone_span_seqbegin(zone);
628 start_pfn = zone->zone_start_pfn;
629 sp = zone->spanned_pages;
630 if (!zone_spans_pfn(zone, pfn))
632 } while (zone_span_seqretry(zone, seq));
635 pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
636 pfn, zone_to_nid(zone), zone->name,
637 start_pfn, start_pfn + sp);
642 static int page_is_consistent(struct zone *zone, struct page *page)
644 if (zone != page_zone(page))
650 * Temporary debugging check for pages not lying within a given zone.
652 static int __maybe_unused bad_range(struct zone *zone, struct page *page)
654 if (page_outside_zone_boundaries(zone, page))
656 if (!page_is_consistent(zone, page))
662 static inline int __maybe_unused bad_range(struct zone *zone, struct page *page)
668 static void bad_page(struct page *page, const char *reason)
670 static unsigned long resume;
671 static unsigned long nr_shown;
672 static unsigned long nr_unshown;
675 * Allow a burst of 60 reports, then keep quiet for that minute;
676 * or allow a steady drip of one report per second.
678 if (nr_shown == 60) {
679 if (time_before(jiffies, resume)) {
685 "BUG: Bad page state: %lu messages suppressed\n",
692 resume = jiffies + 60 * HZ;
694 pr_alert("BUG: Bad page state in process %s pfn:%05lx\n",
695 current->comm, page_to_pfn(page));
696 dump_page(page, reason);
701 /* Leave bad fields for debug, except PageBuddy could make trouble */
702 page_mapcount_reset(page); /* remove PageBuddy */
703 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
706 static inline unsigned int order_to_pindex(int migratetype, int order)
710 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
711 if (order > PAGE_ALLOC_COSTLY_ORDER) {
712 VM_BUG_ON(order != pageblock_order);
713 return NR_LOWORDER_PCP_LISTS;
716 VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
719 return (MIGRATE_PCPTYPES * base) + migratetype;
722 static inline int pindex_to_order(unsigned int pindex)
724 int order = pindex / MIGRATE_PCPTYPES;
726 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
727 if (pindex == NR_LOWORDER_PCP_LISTS)
728 order = pageblock_order;
730 VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
736 static inline bool pcp_allowed_order(unsigned int order)
738 if (order <= PAGE_ALLOC_COSTLY_ORDER)
740 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
741 if (order == pageblock_order)
747 static inline void free_the_page(struct page *page, unsigned int order)
749 if (pcp_allowed_order(order)) /* Via pcp? */
750 free_unref_page(page, order);
752 __free_pages_ok(page, order, FPI_NONE);
756 * Higher-order pages are called "compound pages". They are structured thusly:
758 * The first PAGE_SIZE page is called the "head page" and have PG_head set.
760 * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded
761 * in bit 0 of page->compound_head. The rest of bits is pointer to head page.
763 * The first tail page's ->compound_dtor holds the offset in array of compound
764 * page destructors. See compound_page_dtors.
766 * The first tail page's ->compound_order holds the order of allocation.
767 * This usage means that zero-order pages may not be compound.
770 void free_compound_page(struct page *page)
772 mem_cgroup_uncharge(page_folio(page));
773 free_the_page(page, compound_order(page));
776 static void prep_compound_head(struct page *page, unsigned int order)
778 set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
779 set_compound_order(page, order);
780 atomic_set(compound_mapcount_ptr(page), -1);
781 atomic_set(subpages_mapcount_ptr(page), 0);
782 atomic_set(compound_pincount_ptr(page), 0);
785 static void prep_compound_tail(struct page *head, int tail_idx)
787 struct page *p = head + tail_idx;
789 p->mapping = TAIL_MAPPING;
790 set_compound_head(p, head);
791 set_page_private(p, 0);
794 void prep_compound_page(struct page *page, unsigned int order)
797 int nr_pages = 1 << order;
800 for (i = 1; i < nr_pages; i++)
801 prep_compound_tail(page, i);
803 prep_compound_head(page, order);
806 void destroy_large_folio(struct folio *folio)
808 enum compound_dtor_id dtor = folio_page(folio, 1)->compound_dtor;
810 VM_BUG_ON_FOLIO(dtor >= NR_COMPOUND_DTORS, folio);
811 compound_page_dtors[dtor](&folio->page);
814 #ifdef CONFIG_DEBUG_PAGEALLOC
815 unsigned int _debug_guardpage_minorder;
817 bool _debug_pagealloc_enabled_early __read_mostly
818 = IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
819 EXPORT_SYMBOL(_debug_pagealloc_enabled_early);
820 DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
821 EXPORT_SYMBOL(_debug_pagealloc_enabled);
823 DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
825 static int __init early_debug_pagealloc(char *buf)
827 return kstrtobool(buf, &_debug_pagealloc_enabled_early);
829 early_param("debug_pagealloc", early_debug_pagealloc);
831 static int __init debug_guardpage_minorder_setup(char *buf)
835 if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) {
836 pr_err("Bad debug_guardpage_minorder value\n");
839 _debug_guardpage_minorder = res;
840 pr_info("Setting debug_guardpage_minorder to %lu\n", res);
843 early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
845 static inline bool set_page_guard(struct zone *zone, struct page *page,
846 unsigned int order, int migratetype)
848 if (!debug_guardpage_enabled())
851 if (order >= debug_guardpage_minorder())
854 __SetPageGuard(page);
855 INIT_LIST_HEAD(&page->buddy_list);
856 set_page_private(page, order);
857 /* Guard pages are not available for any usage */
858 if (!is_migrate_isolate(migratetype))
859 __mod_zone_freepage_state(zone, -(1 << order), migratetype);
864 static inline void clear_page_guard(struct zone *zone, struct page *page,
865 unsigned int order, int migratetype)
867 if (!debug_guardpage_enabled())
870 __ClearPageGuard(page);
872 set_page_private(page, 0);
873 if (!is_migrate_isolate(migratetype))
874 __mod_zone_freepage_state(zone, (1 << order), migratetype);
877 static inline bool set_page_guard(struct zone *zone, struct page *page,
878 unsigned int order, int migratetype) { return false; }
879 static inline void clear_page_guard(struct zone *zone, struct page *page,
880 unsigned int order, int migratetype) {}
884 * Enable static keys related to various memory debugging and hardening options.
885 * Some override others, and depend on early params that are evaluated in the
886 * order of appearance. So we need to first gather the full picture of what was
887 * enabled, and then make decisions.
889 void __init init_mem_debugging_and_hardening(void)
891 bool page_poisoning_requested = false;
893 #ifdef CONFIG_PAGE_POISONING
895 * Page poisoning is debug page alloc for some arches. If
896 * either of those options are enabled, enable poisoning.
898 if (page_poisoning_enabled() ||
899 (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) &&
900 debug_pagealloc_enabled())) {
901 static_branch_enable(&_page_poisoning_enabled);
902 page_poisoning_requested = true;
906 if ((_init_on_alloc_enabled_early || _init_on_free_enabled_early) &&
907 page_poisoning_requested) {
908 pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, "
909 "will take precedence over init_on_alloc and init_on_free\n");
910 _init_on_alloc_enabled_early = false;
911 _init_on_free_enabled_early = false;
914 if (_init_on_alloc_enabled_early)
915 static_branch_enable(&init_on_alloc);
917 static_branch_disable(&init_on_alloc);
919 if (_init_on_free_enabled_early)
920 static_branch_enable(&init_on_free);
922 static_branch_disable(&init_on_free);
924 if (IS_ENABLED(CONFIG_KMSAN) &&
925 (_init_on_alloc_enabled_early || _init_on_free_enabled_early))
926 pr_info("mem auto-init: please make sure init_on_alloc and init_on_free are disabled when running KMSAN\n");
928 #ifdef CONFIG_DEBUG_PAGEALLOC
929 if (!debug_pagealloc_enabled())
932 static_branch_enable(&_debug_pagealloc_enabled);
934 if (!debug_guardpage_minorder())
937 static_branch_enable(&_debug_guardpage_enabled);
941 static inline void set_buddy_order(struct page *page, unsigned int order)
943 set_page_private(page, order);
944 __SetPageBuddy(page);
947 #ifdef CONFIG_COMPACTION
948 static inline struct capture_control *task_capc(struct zone *zone)
950 struct capture_control *capc = current->capture_control;
952 return unlikely(capc) &&
953 !(current->flags & PF_KTHREAD) &&
955 capc->cc->zone == zone ? capc : NULL;
959 compaction_capture(struct capture_control *capc, struct page *page,
960 int order, int migratetype)
962 if (!capc || order != capc->cc->order)
965 /* Do not accidentally pollute CMA or isolated regions*/
966 if (is_migrate_cma(migratetype) ||
967 is_migrate_isolate(migratetype))
971 * Do not let lower order allocations pollute a movable pageblock.
972 * This might let an unmovable request use a reclaimable pageblock
973 * and vice-versa but no more than normal fallback logic which can
974 * have trouble finding a high-order free page.
976 if (order < pageblock_order && migratetype == MIGRATE_MOVABLE)
984 static inline struct capture_control *task_capc(struct zone *zone)
990 compaction_capture(struct capture_control *capc, struct page *page,
991 int order, int migratetype)
995 #endif /* CONFIG_COMPACTION */
997 /* Used for pages not on another list */
998 static inline void add_to_free_list(struct page *page, struct zone *zone,
999 unsigned int order, int migratetype)
1001 struct free_area *area = &zone->free_area[order];
1003 list_add(&page->buddy_list, &area->free_list[migratetype]);
1007 /* Used for pages not on another list */
1008 static inline void add_to_free_list_tail(struct page *page, struct zone *zone,
1009 unsigned int order, int migratetype)
1011 struct free_area *area = &zone->free_area[order];
1013 list_add_tail(&page->buddy_list, &area->free_list[migratetype]);
1018 * Used for pages which are on another list. Move the pages to the tail
1019 * of the list - so the moved pages won't immediately be considered for
1020 * allocation again (e.g., optimization for memory onlining).
1022 static inline void move_to_free_list(struct page *page, struct zone *zone,
1023 unsigned int order, int migratetype)
1025 struct free_area *area = &zone->free_area[order];
1027 list_move_tail(&page->buddy_list, &area->free_list[migratetype]);
1030 static inline void del_page_from_free_list(struct page *page, struct zone *zone,
1033 /* clear reported state and update reported page count */
1034 if (page_reported(page))
1035 __ClearPageReported(page);
1037 list_del(&page->buddy_list);
1038 __ClearPageBuddy(page);
1039 set_page_private(page, 0);
1040 zone->free_area[order].nr_free--;
1044 * If this is not the largest possible page, check if the buddy
1045 * of the next-highest order is free. If it is, it's possible
1046 * that pages are being freed that will coalesce soon. In case,
1047 * that is happening, add the free page to the tail of the list
1048 * so it's less likely to be used soon and more likely to be merged
1049 * as a higher order page
1052 buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn,
1053 struct page *page, unsigned int order)
1055 unsigned long higher_page_pfn;
1056 struct page *higher_page;
1058 if (order >= MAX_ORDER - 2)
1061 higher_page_pfn = buddy_pfn & pfn;
1062 higher_page = page + (higher_page_pfn - pfn);
1064 return find_buddy_page_pfn(higher_page, higher_page_pfn, order + 1,
1069 * Freeing function for a buddy system allocator.
1071 * The concept of a buddy system is to maintain direct-mapped table
1072 * (containing bit values) for memory blocks of various "orders".
1073 * The bottom level table contains the map for the smallest allocatable
1074 * units of memory (here, pages), and each level above it describes
1075 * pairs of units from the levels below, hence, "buddies".
1076 * At a high level, all that happens here is marking the table entry
1077 * at the bottom level available, and propagating the changes upward
1078 * as necessary, plus some accounting needed to play nicely with other
1079 * parts of the VM system.
1080 * At each level, we keep a list of pages, which are heads of continuous
1081 * free pages of length of (1 << order) and marked with PageBuddy.
1082 * Page's order is recorded in page_private(page) field.
1083 * So when we are allocating or freeing one, we can derive the state of the
1084 * other. That is, if we allocate a small block, and both were
1085 * free, the remainder of the region must be split into blocks.
1086 * If a block is freed, and its buddy is also free, then this
1087 * triggers coalescing into a block of larger size.
1092 static inline void __free_one_page(struct page *page,
1094 struct zone *zone, unsigned int order,
1095 int migratetype, fpi_t fpi_flags)
1097 struct capture_control *capc = task_capc(zone);
1098 unsigned long buddy_pfn = 0;
1099 unsigned long combined_pfn;
1103 VM_BUG_ON(!zone_is_initialized(zone));
1104 VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
1106 VM_BUG_ON(migratetype == -1);
1107 if (likely(!is_migrate_isolate(migratetype)))
1108 __mod_zone_freepage_state(zone, 1 << order, migratetype);
1110 VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
1111 VM_BUG_ON_PAGE(bad_range(zone, page), page);
1113 while (order < MAX_ORDER - 1) {
1114 if (compaction_capture(capc, page, order, migratetype)) {
1115 __mod_zone_freepage_state(zone, -(1 << order),
1120 buddy = find_buddy_page_pfn(page, pfn, order, &buddy_pfn);
1124 if (unlikely(order >= pageblock_order)) {
1126 * We want to prevent merge between freepages on pageblock
1127 * without fallbacks and normal pageblock. Without this,
1128 * pageblock isolation could cause incorrect freepage or CMA
1129 * accounting or HIGHATOMIC accounting.
1131 int buddy_mt = get_pageblock_migratetype(buddy);
1133 if (migratetype != buddy_mt
1134 && (!migratetype_is_mergeable(migratetype) ||
1135 !migratetype_is_mergeable(buddy_mt)))
1140 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
1141 * merge with it and move up one order.
1143 if (page_is_guard(buddy))
1144 clear_page_guard(zone, buddy, order, migratetype);
1146 del_page_from_free_list(buddy, zone, order);
1147 combined_pfn = buddy_pfn & pfn;
1148 page = page + (combined_pfn - pfn);
1154 set_buddy_order(page, order);
1156 if (fpi_flags & FPI_TO_TAIL)
1158 else if (is_shuffle_order(order))
1159 to_tail = shuffle_pick_tail();
1161 to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order);
1164 add_to_free_list_tail(page, zone, order, migratetype);
1166 add_to_free_list(page, zone, order, migratetype);
1168 /* Notify page reporting subsystem of freed page */
1169 if (!(fpi_flags & FPI_SKIP_REPORT_NOTIFY))
1170 page_reporting_notify_free(order);
1174 * split_free_page() -- split a free page at split_pfn_offset
1175 * @free_page: the original free page
1176 * @order: the order of the page
1177 * @split_pfn_offset: split offset within the page
1179 * Return -ENOENT if the free page is changed, otherwise 0
1181 * It is used when the free page crosses two pageblocks with different migratetypes
1182 * at split_pfn_offset within the page. The split free page will be put into
1183 * separate migratetype lists afterwards. Otherwise, the function achieves
1186 int split_free_page(struct page *free_page,
1187 unsigned int order, unsigned long split_pfn_offset)
1189 struct zone *zone = page_zone(free_page);
1190 unsigned long free_page_pfn = page_to_pfn(free_page);
1192 unsigned long flags;
1193 int free_page_order;
1197 if (split_pfn_offset == 0)
1200 spin_lock_irqsave(&zone->lock, flags);
1202 if (!PageBuddy(free_page) || buddy_order(free_page) != order) {
1207 mt = get_pageblock_migratetype(free_page);
1208 if (likely(!is_migrate_isolate(mt)))
1209 __mod_zone_freepage_state(zone, -(1UL << order), mt);
1211 del_page_from_free_list(free_page, zone, order);
1212 for (pfn = free_page_pfn;
1213 pfn < free_page_pfn + (1UL << order);) {
1214 int mt = get_pfnblock_migratetype(pfn_to_page(pfn), pfn);
1216 free_page_order = min_t(unsigned int,
1217 pfn ? __ffs(pfn) : order,
1218 __fls(split_pfn_offset));
1219 __free_one_page(pfn_to_page(pfn), pfn, zone, free_page_order,
1221 pfn += 1UL << free_page_order;
1222 split_pfn_offset -= (1UL << free_page_order);
1223 /* we have done the first part, now switch to second part */
1224 if (split_pfn_offset == 0)
1225 split_pfn_offset = (1UL << order) - (pfn - free_page_pfn);
1228 spin_unlock_irqrestore(&zone->lock, flags);
1232 * A bad page could be due to a number of fields. Instead of multiple branches,
1233 * try and check multiple fields with one check. The caller must do a detailed
1234 * check if necessary.
1236 static inline bool page_expected_state(struct page *page,
1237 unsigned long check_flags)
1239 if (unlikely(atomic_read(&page->_mapcount) != -1))
1242 if (unlikely((unsigned long)page->mapping |
1243 page_ref_count(page) |
1247 (page->flags & check_flags)))
1253 static const char *page_bad_reason(struct page *page, unsigned long flags)
1255 const char *bad_reason = NULL;
1257 if (unlikely(atomic_read(&page->_mapcount) != -1))
1258 bad_reason = "nonzero mapcount";
1259 if (unlikely(page->mapping != NULL))
1260 bad_reason = "non-NULL mapping";
1261 if (unlikely(page_ref_count(page) != 0))
1262 bad_reason = "nonzero _refcount";
1263 if (unlikely(page->flags & flags)) {
1264 if (flags == PAGE_FLAGS_CHECK_AT_PREP)
1265 bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag(s) set";
1267 bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
1270 if (unlikely(page->memcg_data))
1271 bad_reason = "page still charged to cgroup";
1276 static void free_page_is_bad_report(struct page *page)
1279 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_FREE));
1282 static inline bool free_page_is_bad(struct page *page)
1284 if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE)))
1287 /* Something has gone sideways, find it */
1288 free_page_is_bad_report(page);
1292 static int free_tail_pages_check(struct page *head_page, struct page *page)
1297 * We rely page->lru.next never has bit 0 set, unless the page
1298 * is PageTail(). Let's make sure that's true even for poisoned ->lru.
1300 BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1);
1302 if (!IS_ENABLED(CONFIG_DEBUG_VM)) {
1306 switch (page - head_page) {
1308 /* the first tail page: these may be in place of ->mapping */
1309 if (unlikely(head_compound_mapcount(head_page))) {
1310 bad_page(page, "nonzero compound_mapcount");
1313 if (unlikely(atomic_read(subpages_mapcount_ptr(head_page)))) {
1314 bad_page(page, "nonzero subpages_mapcount");
1317 if (unlikely(head_compound_pincount(head_page))) {
1318 bad_page(page, "nonzero compound_pincount");
1324 * the second tail page: ->mapping is
1325 * deferred_list.next -- ignore value.
1329 if (page->mapping != TAIL_MAPPING) {
1330 bad_page(page, "corrupted mapping in tail page");
1335 if (unlikely(!PageTail(page))) {
1336 bad_page(page, "PageTail not set");
1339 if (unlikely(compound_head(page) != head_page)) {
1340 bad_page(page, "compound_head not consistent");
1345 page->mapping = NULL;
1346 clear_compound_head(page);
1351 * Skip KASAN memory poisoning when either:
1353 * 1. Deferred memory initialization has not yet completed,
1354 * see the explanation below.
1355 * 2. Skipping poisoning is requested via FPI_SKIP_KASAN_POISON,
1356 * see the comment next to it.
1357 * 3. Skipping poisoning is requested via __GFP_SKIP_KASAN_POISON,
1358 * see the comment next to it.
1360 * Poisoning pages during deferred memory init will greatly lengthen the
1361 * process and cause problem in large memory systems as the deferred pages
1362 * initialization is done with interrupt disabled.
1364 * Assuming that there will be no reference to those newly initialized
1365 * pages before they are ever allocated, this should have no effect on
1366 * KASAN memory tracking as the poison will be properly inserted at page
1367 * allocation time. The only corner case is when pages are allocated by
1368 * on-demand allocation and then freed again before the deferred pages
1369 * initialization is done, but this is not likely to happen.
1371 static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags)
1373 return deferred_pages_enabled() ||
1374 (!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
1375 (fpi_flags & FPI_SKIP_KASAN_POISON)) ||
1376 PageSkipKASanPoison(page);
1379 static void kernel_init_pages(struct page *page, int numpages)
1383 /* s390's use of memset() could override KASAN redzones. */
1384 kasan_disable_current();
1385 for (i = 0; i < numpages; i++)
1386 clear_highpage_kasan_tagged(page + i);
1387 kasan_enable_current();
1390 static __always_inline bool free_pages_prepare(struct page *page,
1391 unsigned int order, bool check_free, fpi_t fpi_flags)
1394 bool init = want_init_on_free();
1396 VM_BUG_ON_PAGE(PageTail(page), page);
1398 trace_mm_page_free(page, order);
1399 kmsan_free_page(page, order);
1401 if (unlikely(PageHWPoison(page)) && !order) {
1403 * Do not let hwpoison pages hit pcplists/buddy
1404 * Untie memcg state and reset page's owner
1406 if (memcg_kmem_enabled() && PageMemcgKmem(page))
1407 __memcg_kmem_uncharge_page(page, order);
1408 reset_page_owner(page, order);
1409 page_table_check_free(page, order);
1414 * Check tail pages before head page information is cleared to
1415 * avoid checking PageCompound for order-0 pages.
1417 if (unlikely(order)) {
1418 bool compound = PageCompound(page);
1421 VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
1424 ClearPageHasHWPoisoned(page);
1425 for (i = 1; i < (1 << order); i++) {
1427 bad += free_tail_pages_check(page, page + i);
1428 if (unlikely(free_page_is_bad(page + i))) {
1432 (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1435 if (PageMappingFlags(page))
1436 page->mapping = NULL;
1437 if (memcg_kmem_enabled() && PageMemcgKmem(page))
1438 __memcg_kmem_uncharge_page(page, order);
1439 if (check_free && free_page_is_bad(page))
1444 page_cpupid_reset_last(page);
1445 page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1446 reset_page_owner(page, order);
1447 page_table_check_free(page, order);
1449 if (!PageHighMem(page)) {
1450 debug_check_no_locks_freed(page_address(page),
1451 PAGE_SIZE << order);
1452 debug_check_no_obj_freed(page_address(page),
1453 PAGE_SIZE << order);
1456 kernel_poison_pages(page, 1 << order);
1459 * As memory initialization might be integrated into KASAN,
1460 * KASAN poisoning and memory initialization code must be
1461 * kept together to avoid discrepancies in behavior.
1463 * With hardware tag-based KASAN, memory tags must be set before the
1464 * page becomes unavailable via debug_pagealloc or arch_free_page.
1466 if (!should_skip_kasan_poison(page, fpi_flags)) {
1467 kasan_poison_pages(page, order, init);
1469 /* Memory is already initialized if KASAN did it internally. */
1470 if (kasan_has_integrated_init())
1474 kernel_init_pages(page, 1 << order);
1477 * arch_free_page() can make the page's contents inaccessible. s390
1478 * does this. So nothing which can access the page's contents should
1479 * happen after this.
1481 arch_free_page(page, order);
1483 debug_pagealloc_unmap_pages(page, 1 << order);
1488 #ifdef CONFIG_DEBUG_VM
1490 * With DEBUG_VM enabled, order-0 pages are checked immediately when being freed
1491 * to pcp lists. With debug_pagealloc also enabled, they are also rechecked when
1492 * moved from pcp lists to free lists.
1494 static bool free_pcp_prepare(struct page *page, unsigned int order)
1496 return free_pages_prepare(page, order, true, FPI_NONE);
1499 /* return true if this page has an inappropriate state */
1500 static bool bulkfree_pcp_prepare(struct page *page)
1502 if (debug_pagealloc_enabled_static())
1503 return free_page_is_bad(page);
1509 * With DEBUG_VM disabled, order-0 pages being freed are checked only when
1510 * moving from pcp lists to free list in order to reduce overhead. With
1511 * debug_pagealloc enabled, they are checked also immediately when being freed
1514 static bool free_pcp_prepare(struct page *page, unsigned int order)
1516 if (debug_pagealloc_enabled_static())
1517 return free_pages_prepare(page, order, true, FPI_NONE);
1519 return free_pages_prepare(page, order, false, FPI_NONE);
1522 static bool bulkfree_pcp_prepare(struct page *page)
1524 return free_page_is_bad(page);
1526 #endif /* CONFIG_DEBUG_VM */
1529 * Frees a number of pages from the PCP lists
1530 * Assumes all pages on list are in same zone.
1531 * count is the number of pages to free.
1533 static void free_pcppages_bulk(struct zone *zone, int count,
1534 struct per_cpu_pages *pcp,
1537 unsigned long flags;
1539 int max_pindex = NR_PCP_LISTS - 1;
1541 bool isolated_pageblocks;
1545 * Ensure proper count is passed which otherwise would stuck in the
1546 * below while (list_empty(list)) loop.
1548 count = min(pcp->count, count);
1550 /* Ensure requested pindex is drained first. */
1551 pindex = pindex - 1;
1553 spin_lock_irqsave(&zone->lock, flags);
1554 isolated_pageblocks = has_isolate_pageblock(zone);
1557 struct list_head *list;
1560 /* Remove pages from lists in a round-robin fashion. */
1562 if (++pindex > max_pindex)
1563 pindex = min_pindex;
1564 list = &pcp->lists[pindex];
1565 if (!list_empty(list))
1568 if (pindex == max_pindex)
1570 if (pindex == min_pindex)
1574 order = pindex_to_order(pindex);
1575 nr_pages = 1 << order;
1579 page = list_last_entry(list, struct page, pcp_list);
1580 mt = get_pcppage_migratetype(page);
1582 /* must delete to avoid corrupting pcp list */
1583 list_del(&page->pcp_list);
1585 pcp->count -= nr_pages;
1587 if (bulkfree_pcp_prepare(page))
1590 /* MIGRATE_ISOLATE page should not go to pcplists */
1591 VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
1592 /* Pageblock could have been isolated meanwhile */
1593 if (unlikely(isolated_pageblocks))
1594 mt = get_pageblock_migratetype(page);
1596 __free_one_page(page, page_to_pfn(page), zone, order, mt, FPI_NONE);
1597 trace_mm_page_pcpu_drain(page, order, mt);
1598 } while (count > 0 && !list_empty(list));
1601 spin_unlock_irqrestore(&zone->lock, flags);
1604 static void free_one_page(struct zone *zone,
1605 struct page *page, unsigned long pfn,
1607 int migratetype, fpi_t fpi_flags)
1609 unsigned long flags;
1611 spin_lock_irqsave(&zone->lock, flags);
1612 if (unlikely(has_isolate_pageblock(zone) ||
1613 is_migrate_isolate(migratetype))) {
1614 migratetype = get_pfnblock_migratetype(page, pfn);
1616 __free_one_page(page, pfn, zone, order, migratetype, fpi_flags);
1617 spin_unlock_irqrestore(&zone->lock, flags);
1620 static void __meminit __init_single_page(struct page *page, unsigned long pfn,
1621 unsigned long zone, int nid)
1623 mm_zero_struct_page(page);
1624 set_page_links(page, zone, nid, pfn);
1625 init_page_count(page);
1626 page_mapcount_reset(page);
1627 page_cpupid_reset_last(page);
1628 page_kasan_tag_reset(page);
1630 INIT_LIST_HEAD(&page->lru);
1631 #ifdef WANT_PAGE_VIRTUAL
1632 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
1633 if (!is_highmem_idx(zone))
1634 set_page_address(page, __va(pfn << PAGE_SHIFT));
1638 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1639 static void __meminit init_reserved_page(unsigned long pfn)
1644 if (!early_page_uninitialised(pfn))
1647 nid = early_pfn_to_nid(pfn);
1648 pgdat = NODE_DATA(nid);
1650 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1651 struct zone *zone = &pgdat->node_zones[zid];
1653 if (zone_spans_pfn(zone, pfn))
1656 __init_single_page(pfn_to_page(pfn), pfn, zid, nid);
1659 static inline void init_reserved_page(unsigned long pfn)
1662 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1665 * Initialised pages do not have PageReserved set. This function is
1666 * called for each range allocated by the bootmem allocator and
1667 * marks the pages PageReserved. The remaining valid pages are later
1668 * sent to the buddy page allocator.
1670 void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
1672 unsigned long start_pfn = PFN_DOWN(start);
1673 unsigned long end_pfn = PFN_UP(end);
1675 for (; start_pfn < end_pfn; start_pfn++) {
1676 if (pfn_valid(start_pfn)) {
1677 struct page *page = pfn_to_page(start_pfn);
1679 init_reserved_page(start_pfn);
1681 /* Avoid false-positive PageTail() */
1682 INIT_LIST_HEAD(&page->lru);
1685 * no need for atomic set_bit because the struct
1686 * page is not visible yet so nobody should
1689 __SetPageReserved(page);
1694 static void __free_pages_ok(struct page *page, unsigned int order,
1697 unsigned long flags;
1699 unsigned long pfn = page_to_pfn(page);
1700 struct zone *zone = page_zone(page);
1702 if (!free_pages_prepare(page, order, true, fpi_flags))
1706 * Calling get_pfnblock_migratetype() without spin_lock_irqsave() here
1707 * is used to avoid calling get_pfnblock_migratetype() under the lock.
1708 * This will reduce the lock holding time.
1710 migratetype = get_pfnblock_migratetype(page, pfn);
1712 spin_lock_irqsave(&zone->lock, flags);
1713 if (unlikely(has_isolate_pageblock(zone) ||
1714 is_migrate_isolate(migratetype))) {
1715 migratetype = get_pfnblock_migratetype(page, pfn);
1717 __free_one_page(page, pfn, zone, order, migratetype, fpi_flags);
1718 spin_unlock_irqrestore(&zone->lock, flags);
1720 __count_vm_events(PGFREE, 1 << order);
1723 void __free_pages_core(struct page *page, unsigned int order)
1725 unsigned int nr_pages = 1 << order;
1726 struct page *p = page;
1730 * When initializing the memmap, __init_single_page() sets the refcount
1731 * of all pages to 1 ("allocated"/"not free"). We have to set the
1732 * refcount of all involved pages to 0.
1735 for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
1737 __ClearPageReserved(p);
1738 set_page_count(p, 0);
1740 __ClearPageReserved(p);
1741 set_page_count(p, 0);
1743 atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
1746 * Bypass PCP and place fresh pages right to the tail, primarily
1747 * relevant for memory onlining.
1749 __free_pages_ok(page, order, FPI_TO_TAIL | FPI_SKIP_KASAN_POISON);
1755 * During memory init memblocks map pfns to nids. The search is expensive and
1756 * this caches recent lookups. The implementation of __early_pfn_to_nid
1757 * treats start/end as pfns.
1759 struct mminit_pfnnid_cache {
1760 unsigned long last_start;
1761 unsigned long last_end;
1765 static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
1768 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
1770 static int __meminit __early_pfn_to_nid(unsigned long pfn,
1771 struct mminit_pfnnid_cache *state)
1773 unsigned long start_pfn, end_pfn;
1776 if (state->last_start <= pfn && pfn < state->last_end)
1777 return state->last_nid;
1779 nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
1780 if (nid != NUMA_NO_NODE) {
1781 state->last_start = start_pfn;
1782 state->last_end = end_pfn;
1783 state->last_nid = nid;
1789 int __meminit early_pfn_to_nid(unsigned long pfn)
1791 static DEFINE_SPINLOCK(early_pfn_lock);
1794 spin_lock(&early_pfn_lock);
1795 nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
1797 nid = first_online_node;
1798 spin_unlock(&early_pfn_lock);
1802 #endif /* CONFIG_NUMA */
1804 void __init memblock_free_pages(struct page *page, unsigned long pfn,
1807 if (early_page_uninitialised(pfn))
1809 if (!kmsan_memblock_free_pages(page, order)) {
1810 /* KMSAN will take care of these pages. */
1813 __free_pages_core(page, order);
1817 * Check that the whole (or subset of) a pageblock given by the interval of
1818 * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
1819 * with the migration of free compaction scanner.
1821 * Return struct page pointer of start_pfn, or NULL if checks were not passed.
1823 * It's possible on some configurations to have a setup like node0 node1 node0
1824 * i.e. it's possible that all pages within a zones range of pages do not
1825 * belong to a single zone. We assume that a border between node0 and node1
1826 * can occur within a single pageblock, but not a node0 node1 node0
1827 * interleaving within a single pageblock. It is therefore sufficient to check
1828 * the first and last page of a pageblock and avoid checking each individual
1829 * page in a pageblock.
1831 struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
1832 unsigned long end_pfn, struct zone *zone)
1834 struct page *start_page;
1835 struct page *end_page;
1837 /* end_pfn is one past the range we are checking */
1840 if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
1843 start_page = pfn_to_online_page(start_pfn);
1847 if (page_zone(start_page) != zone)
1850 end_page = pfn_to_page(end_pfn);
1852 /* This gives a shorter code than deriving page_zone(end_page) */
1853 if (page_zone_id(start_page) != page_zone_id(end_page))
1859 void set_zone_contiguous(struct zone *zone)
1861 unsigned long block_start_pfn = zone->zone_start_pfn;
1862 unsigned long block_end_pfn;
1864 block_end_pfn = pageblock_end_pfn(block_start_pfn);
1865 for (; block_start_pfn < zone_end_pfn(zone);
1866 block_start_pfn = block_end_pfn,
1867 block_end_pfn += pageblock_nr_pages) {
1869 block_end_pfn = min(block_end_pfn, zone_end_pfn(zone));
1871 if (!__pageblock_pfn_to_page(block_start_pfn,
1872 block_end_pfn, zone))
1877 /* We confirm that there is no hole */
1878 zone->contiguous = true;
1881 void clear_zone_contiguous(struct zone *zone)
1883 zone->contiguous = false;
1886 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1887 static void __init deferred_free_range(unsigned long pfn,
1888 unsigned long nr_pages)
1896 page = pfn_to_page(pfn);
1898 /* Free a large naturally-aligned chunk if possible */
1899 if (nr_pages == pageblock_nr_pages && pageblock_aligned(pfn)) {
1900 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1901 __free_pages_core(page, pageblock_order);
1905 for (i = 0; i < nr_pages; i++, page++, pfn++) {
1906 if (pageblock_aligned(pfn))
1907 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1908 __free_pages_core(page, 0);
1912 /* Completion tracking for deferred_init_memmap() threads */
1913 static atomic_t pgdat_init_n_undone __initdata;
1914 static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp);
1916 static inline void __init pgdat_init_report_one_done(void)
1918 if (atomic_dec_and_test(&pgdat_init_n_undone))
1919 complete(&pgdat_init_all_done_comp);
1923 * Returns true if page needs to be initialized or freed to buddy allocator.
1925 * We check if a current large page is valid by only checking the validity
1928 static inline bool __init deferred_pfn_valid(unsigned long pfn)
1930 if (pageblock_aligned(pfn) && !pfn_valid(pfn))
1936 * Free pages to buddy allocator. Try to free aligned pages in
1937 * pageblock_nr_pages sizes.
1939 static void __init deferred_free_pages(unsigned long pfn,
1940 unsigned long end_pfn)
1942 unsigned long nr_free = 0;
1944 for (; pfn < end_pfn; pfn++) {
1945 if (!deferred_pfn_valid(pfn)) {
1946 deferred_free_range(pfn - nr_free, nr_free);
1948 } else if (pageblock_aligned(pfn)) {
1949 deferred_free_range(pfn - nr_free, nr_free);
1955 /* Free the last block of pages to allocator */
1956 deferred_free_range(pfn - nr_free, nr_free);
1960 * Initialize struct pages. We minimize pfn page lookups and scheduler checks
1961 * by performing it only once every pageblock_nr_pages.
1962 * Return number of pages initialized.
1964 static unsigned long __init deferred_init_pages(struct zone *zone,
1966 unsigned long end_pfn)
1968 int nid = zone_to_nid(zone);
1969 unsigned long nr_pages = 0;
1970 int zid = zone_idx(zone);
1971 struct page *page = NULL;
1973 for (; pfn < end_pfn; pfn++) {
1974 if (!deferred_pfn_valid(pfn)) {
1977 } else if (!page || pageblock_aligned(pfn)) {
1978 page = pfn_to_page(pfn);
1982 __init_single_page(page, pfn, zid, nid);
1989 * This function is meant to pre-load the iterator for the zone init.
1990 * Specifically it walks through the ranges until we are caught up to the
1991 * first_init_pfn value and exits there. If we never encounter the value we
1992 * return false indicating there are no valid ranges left.
1995 deferred_init_mem_pfn_range_in_zone(u64 *i, struct zone *zone,
1996 unsigned long *spfn, unsigned long *epfn,
1997 unsigned long first_init_pfn)
2002 * Start out by walking through the ranges in this zone that have
2003 * already been initialized. We don't need to do anything with them
2004 * so we just need to flush them out of the system.
2006 for_each_free_mem_pfn_range_in_zone(j, zone, spfn, epfn) {
2007 if (*epfn <= first_init_pfn)
2009 if (*spfn < first_init_pfn)
2010 *spfn = first_init_pfn;
2019 * Initialize and free pages. We do it in two loops: first we initialize
2020 * struct page, then free to buddy allocator, because while we are
2021 * freeing pages we can access pages that are ahead (computing buddy
2022 * page in __free_one_page()).
2024 * In order to try and keep some memory in the cache we have the loop
2025 * broken along max page order boundaries. This way we will not cause
2026 * any issues with the buddy page computation.
2028 static unsigned long __init
2029 deferred_init_maxorder(u64 *i, struct zone *zone, unsigned long *start_pfn,
2030 unsigned long *end_pfn)
2032 unsigned long mo_pfn = ALIGN(*start_pfn + 1, MAX_ORDER_NR_PAGES);
2033 unsigned long spfn = *start_pfn, epfn = *end_pfn;
2034 unsigned long nr_pages = 0;
2037 /* First we loop through and initialize the page values */
2038 for_each_free_mem_pfn_range_in_zone_from(j, zone, start_pfn, end_pfn) {
2041 if (mo_pfn <= *start_pfn)
2044 t = min(mo_pfn, *end_pfn);
2045 nr_pages += deferred_init_pages(zone, *start_pfn, t);
2047 if (mo_pfn < *end_pfn) {
2048 *start_pfn = mo_pfn;
2053 /* Reset values and now loop through freeing pages as needed */
2056 for_each_free_mem_pfn_range_in_zone_from(j, zone, &spfn, &epfn) {
2062 t = min(mo_pfn, epfn);
2063 deferred_free_pages(spfn, t);
2073 deferred_init_memmap_chunk(unsigned long start_pfn, unsigned long end_pfn,
2076 unsigned long spfn, epfn;
2077 struct zone *zone = arg;
2080 deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, start_pfn);
2083 * Initialize and free pages in MAX_ORDER sized increments so that we
2084 * can avoid introducing any issues with the buddy allocator.
2086 while (spfn < end_pfn) {
2087 deferred_init_maxorder(&i, zone, &spfn, &epfn);
2092 /* An arch may override for more concurrency. */
2094 deferred_page_init_max_threads(const struct cpumask *node_cpumask)
2099 /* Initialise remaining memory on a node */
2100 static int __init deferred_init_memmap(void *data)
2102 pg_data_t *pgdat = data;
2103 const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
2104 unsigned long spfn = 0, epfn = 0;
2105 unsigned long first_init_pfn, flags;
2106 unsigned long start = jiffies;
2108 int zid, max_threads;
2111 /* Bind memory initialisation thread to a local node if possible */
2112 if (!cpumask_empty(cpumask))
2113 set_cpus_allowed_ptr(current, cpumask);
2115 pgdat_resize_lock(pgdat, &flags);
2116 first_init_pfn = pgdat->first_deferred_pfn;
2117 if (first_init_pfn == ULONG_MAX) {
2118 pgdat_resize_unlock(pgdat, &flags);
2119 pgdat_init_report_one_done();
2123 /* Sanity check boundaries */
2124 BUG_ON(pgdat->first_deferred_pfn < pgdat->node_start_pfn);
2125 BUG_ON(pgdat->first_deferred_pfn > pgdat_end_pfn(pgdat));
2126 pgdat->first_deferred_pfn = ULONG_MAX;
2129 * Once we unlock here, the zone cannot be grown anymore, thus if an
2130 * interrupt thread must allocate this early in boot, zone must be
2131 * pre-grown prior to start of deferred page initialization.
2133 pgdat_resize_unlock(pgdat, &flags);
2135 /* Only the highest zone is deferred so find it */
2136 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
2137 zone = pgdat->node_zones + zid;
2138 if (first_init_pfn < zone_end_pfn(zone))
2142 /* If the zone is empty somebody else may have cleared out the zone */
2143 if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
2147 max_threads = deferred_page_init_max_threads(cpumask);
2149 while (spfn < epfn) {
2150 unsigned long epfn_align = ALIGN(epfn, PAGES_PER_SECTION);
2151 struct padata_mt_job job = {
2152 .thread_fn = deferred_init_memmap_chunk,
2155 .size = epfn_align - spfn,
2156 .align = PAGES_PER_SECTION,
2157 .min_chunk = PAGES_PER_SECTION,
2158 .max_threads = max_threads,
2161 padata_do_multithreaded(&job);
2162 deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
2166 /* Sanity check that the next zone really is unpopulated */
2167 WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));
2169 pr_info("node %d deferred pages initialised in %ums\n",
2170 pgdat->node_id, jiffies_to_msecs(jiffies - start));
2172 pgdat_init_report_one_done();
2177 * If this zone has deferred pages, try to grow it by initializing enough
2178 * deferred pages to satisfy the allocation specified by order, rounded up to
2179 * the nearest PAGES_PER_SECTION boundary. So we're adding memory in increments
2180 * of SECTION_SIZE bytes by initializing struct pages in increments of
2181 * PAGES_PER_SECTION * sizeof(struct page) bytes.
2183 * Return true when zone was grown, otherwise return false. We return true even
2184 * when we grow less than requested, to let the caller decide if there are
2185 * enough pages to satisfy the allocation.
2187 * Note: We use noinline because this function is needed only during boot, and
2188 * it is called from a __ref function _deferred_grow_zone. This way we are
2189 * making sure that it is not inlined into permanent text section.
2191 static noinline bool __init
2192 deferred_grow_zone(struct zone *zone, unsigned int order)
2194 unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION);
2195 pg_data_t *pgdat = zone->zone_pgdat;
2196 unsigned long first_deferred_pfn = pgdat->first_deferred_pfn;
2197 unsigned long spfn, epfn, flags;
2198 unsigned long nr_pages = 0;
2201 /* Only the last zone may have deferred pages */
2202 if (zone_end_pfn(zone) != pgdat_end_pfn(pgdat))
2205 pgdat_resize_lock(pgdat, &flags);
2208 * If someone grew this zone while we were waiting for spinlock, return
2209 * true, as there might be enough pages already.
2211 if (first_deferred_pfn != pgdat->first_deferred_pfn) {
2212 pgdat_resize_unlock(pgdat, &flags);
2216 /* If the zone is empty somebody else may have cleared out the zone */
2217 if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
2218 first_deferred_pfn)) {
2219 pgdat->first_deferred_pfn = ULONG_MAX;
2220 pgdat_resize_unlock(pgdat, &flags);
2221 /* Retry only once. */
2222 return first_deferred_pfn != ULONG_MAX;
2226 * Initialize and free pages in MAX_ORDER sized increments so
2227 * that we can avoid introducing any issues with the buddy
2230 while (spfn < epfn) {
2231 /* update our first deferred PFN for this section */
2232 first_deferred_pfn = spfn;
2234 nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
2235 touch_nmi_watchdog();
2237 /* We should only stop along section boundaries */
2238 if ((first_deferred_pfn ^ spfn) < PAGES_PER_SECTION)
2241 /* If our quota has been met we can stop here */
2242 if (nr_pages >= nr_pages_needed)
2246 pgdat->first_deferred_pfn = spfn;
2247 pgdat_resize_unlock(pgdat, &flags);
2249 return nr_pages > 0;
2253 * deferred_grow_zone() is __init, but it is called from
2254 * get_page_from_freelist() during early boot until deferred_pages permanently
2255 * disables this call. This is why we have refdata wrapper to avoid warning,
2256 * and to ensure that the function body gets unloaded.
2259 _deferred_grow_zone(struct zone *zone, unsigned int order)
2261 return deferred_grow_zone(zone, order);
2264 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
2266 void __init page_alloc_init_late(void)
2271 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
2273 /* There will be num_node_state(N_MEMORY) threads */
2274 atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY));
2275 for_each_node_state(nid, N_MEMORY) {
2276 kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid);
2279 /* Block until all are initialised */
2280 wait_for_completion(&pgdat_init_all_done_comp);
2283 * We initialized the rest of the deferred pages. Permanently disable
2284 * on-demand struct page initialization.
2286 static_branch_disable(&deferred_pages);
2288 /* Reinit limits that are based on free pages after the kernel is up */
2289 files_maxfiles_init();
2294 /* Discard memblock private memory */
2297 for_each_node_state(nid, N_MEMORY)
2298 shuffle_free_memory(NODE_DATA(nid));
2300 for_each_populated_zone(zone)
2301 set_zone_contiguous(zone);
2305 /* Free whole pageblock and set its migration type to MIGRATE_CMA. */
2306 void __init init_cma_reserved_pageblock(struct page *page)
2308 unsigned i = pageblock_nr_pages;
2309 struct page *p = page;
2312 __ClearPageReserved(p);
2313 set_page_count(p, 0);
2316 set_pageblock_migratetype(page, MIGRATE_CMA);
2317 set_page_refcounted(page);
2318 __free_pages(page, pageblock_order);
2320 adjust_managed_page_count(page, pageblock_nr_pages);
2321 page_zone(page)->cma_pages += pageblock_nr_pages;
2326 * The order of subdivision here is critical for the IO subsystem.
2327 * Please do not alter this order without good reasons and regression
2328 * testing. Specifically, as large blocks of memory are subdivided,
2329 * the order in which smaller blocks are delivered depends on the order
2330 * they're subdivided in this function. This is the primary factor
2331 * influencing the order in which pages are delivered to the IO
2332 * subsystem according to empirical testing, and this is also justified
2333 * by considering the behavior of a buddy system containing a single
2334 * large block of memory acted on by a series of small allocations.
2335 * This behavior is a critical factor in sglist merging's success.
2339 static inline void expand(struct zone *zone, struct page *page,
2340 int low, int high, int migratetype)
2342 unsigned long size = 1 << high;
2344 while (high > low) {
2347 VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
2350 * Mark as guard pages (or page), that will allow to
2351 * merge back to allocator when buddy will be freed.
2352 * Corresponding page table entries will not be touched,
2353 * pages will stay not present in virtual address space
2355 if (set_page_guard(zone, &page[size], high, migratetype))
2358 add_to_free_list(&page[size], zone, high, migratetype);
2359 set_buddy_order(&page[size], high);
2363 static void check_new_page_bad(struct page *page)
2365 if (unlikely(page->flags & __PG_HWPOISON)) {
2366 /* Don't complain about hwpoisoned pages */
2367 page_mapcount_reset(page); /* remove PageBuddy */
2372 page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP));
2376 * This page is about to be returned from the page allocator
2378 static inline int check_new_page(struct page *page)
2380 if (likely(page_expected_state(page,
2381 PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON)))
2384 check_new_page_bad(page);
2388 static bool check_new_pages(struct page *page, unsigned int order)
2391 for (i = 0; i < (1 << order); i++) {
2392 struct page *p = page + i;
2394 if (unlikely(check_new_page(p)))
2401 #ifdef CONFIG_DEBUG_VM
2403 * With DEBUG_VM enabled, order-0 pages are checked for expected state when
2404 * being allocated from pcp lists. With debug_pagealloc also enabled, they are
2405 * also checked when pcp lists are refilled from the free lists.
2407 static inline bool check_pcp_refill(struct page *page, unsigned int order)
2409 if (debug_pagealloc_enabled_static())
2410 return check_new_pages(page, order);
2415 static inline bool check_new_pcp(struct page *page, unsigned int order)
2417 return check_new_pages(page, order);
2421 * With DEBUG_VM disabled, free order-0 pages are checked for expected state
2422 * when pcp lists are being refilled from the free lists. With debug_pagealloc
2423 * enabled, they are also checked when being allocated from the pcp lists.
2425 static inline bool check_pcp_refill(struct page *page, unsigned int order)
2427 return check_new_pages(page, order);
2429 static inline bool check_new_pcp(struct page *page, unsigned int order)
2431 if (debug_pagealloc_enabled_static())
2432 return check_new_pages(page, order);
2436 #endif /* CONFIG_DEBUG_VM */
2438 static inline bool should_skip_kasan_unpoison(gfp_t flags)
2440 /* Don't skip if a software KASAN mode is enabled. */
2441 if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
2442 IS_ENABLED(CONFIG_KASAN_SW_TAGS))
2445 /* Skip, if hardware tag-based KASAN is not enabled. */
2446 if (!kasan_hw_tags_enabled())
2450 * With hardware tag-based KASAN enabled, skip if this has been
2451 * requested via __GFP_SKIP_KASAN_UNPOISON.
2453 return flags & __GFP_SKIP_KASAN_UNPOISON;
2456 static inline bool should_skip_init(gfp_t flags)
2458 /* Don't skip, if hardware tag-based KASAN is not enabled. */
2459 if (!kasan_hw_tags_enabled())
2462 /* For hardware tag-based KASAN, skip if requested. */
2463 return (flags & __GFP_SKIP_ZERO);
2466 inline void post_alloc_hook(struct page *page, unsigned int order,
2469 bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags) &&
2470 !should_skip_init(gfp_flags);
2471 bool init_tags = init && (gfp_flags & __GFP_ZEROTAGS);
2474 set_page_private(page, 0);
2475 set_page_refcounted(page);
2477 arch_alloc_page(page, order);
2478 debug_pagealloc_map_pages(page, 1 << order);
2481 * Page unpoisoning must happen before memory initialization.
2482 * Otherwise, the poison pattern will be overwritten for __GFP_ZERO
2483 * allocations and the page unpoisoning code will complain.
2485 kernel_unpoison_pages(page, 1 << order);
2488 * As memory initialization might be integrated into KASAN,
2489 * KASAN unpoisoning and memory initializion code must be
2490 * kept together to avoid discrepancies in behavior.
2494 * If memory tags should be zeroed (which happens only when memory
2495 * should be initialized as well).
2498 /* Initialize both memory and tags. */
2499 for (i = 0; i != 1 << order; ++i)
2500 tag_clear_highpage(page + i);
2502 /* Note that memory is already initialized by the loop above. */
2505 if (!should_skip_kasan_unpoison(gfp_flags)) {
2506 /* Unpoison shadow memory or set memory tags. */
2507 kasan_unpoison_pages(page, order, init);
2509 /* Note that memory is already initialized by KASAN. */
2510 if (kasan_has_integrated_init())
2513 /* Ensure page_address() dereferencing does not fault. */
2514 for (i = 0; i != 1 << order; ++i)
2515 page_kasan_tag_reset(page + i);
2517 /* If memory is still not initialized, do it now. */
2519 kernel_init_pages(page, 1 << order);
2520 /* Propagate __GFP_SKIP_KASAN_POISON to page flags. */
2521 if (kasan_hw_tags_enabled() && (gfp_flags & __GFP_SKIP_KASAN_POISON))
2522 SetPageSkipKASanPoison(page);
2524 set_page_owner(page, order, gfp_flags);
2525 page_table_check_alloc(page, order);
2528 static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
2529 unsigned int alloc_flags)
2531 post_alloc_hook(page, order, gfp_flags);
2533 if (order && (gfp_flags & __GFP_COMP))
2534 prep_compound_page(page, order);
2537 * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
2538 * allocate the page. The expectation is that the caller is taking
2539 * steps that will free more memory. The caller should avoid the page
2540 * being used for !PFMEMALLOC purposes.
2542 if (alloc_flags & ALLOC_NO_WATERMARKS)
2543 set_page_pfmemalloc(page);
2545 clear_page_pfmemalloc(page);
2549 * Go through the free lists for the given migratetype and remove
2550 * the smallest available page from the freelists
2552 static __always_inline
2553 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
2556 unsigned int current_order;
2557 struct free_area *area;
2560 /* Find a page of the appropriate size in the preferred list */
2561 for (current_order = order; current_order < MAX_ORDER; ++current_order) {
2562 area = &(zone->free_area[current_order]);
2563 page = get_page_from_free_area(area, migratetype);
2566 del_page_from_free_list(page, zone, current_order);
2567 expand(zone, page, order, current_order, migratetype);
2568 set_pcppage_migratetype(page, migratetype);
2569 trace_mm_page_alloc_zone_locked(page, order, migratetype,
2570 pcp_allowed_order(order) &&
2571 migratetype < MIGRATE_PCPTYPES);
2580 * This array describes the order lists are fallen back to when
2581 * the free lists for the desirable migrate type are depleted
2583 * The other migratetypes do not have fallbacks.
2585 static int fallbacks[MIGRATE_TYPES][3] = {
2586 [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
2587 [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
2588 [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
2592 static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone,
2595 return __rmqueue_smallest(zone, order, MIGRATE_CMA);
2598 static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
2599 unsigned int order) { return NULL; }
2603 * Move the free pages in a range to the freelist tail of the requested type.
2604 * Note that start_page and end_pages are not aligned on a pageblock
2605 * boundary. If alignment is required, use move_freepages_block()
2607 static int move_freepages(struct zone *zone,
2608 unsigned long start_pfn, unsigned long end_pfn,
2609 int migratetype, int *num_movable)
2614 int pages_moved = 0;
2616 for (pfn = start_pfn; pfn <= end_pfn;) {
2617 page = pfn_to_page(pfn);
2618 if (!PageBuddy(page)) {
2620 * We assume that pages that could be isolated for
2621 * migration are movable. But we don't actually try
2622 * isolating, as that would be expensive.
2625 (PageLRU(page) || __PageMovable(page)))
2631 /* Make sure we are not inadvertently changing nodes */
2632 VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
2633 VM_BUG_ON_PAGE(page_zone(page) != zone, page);
2635 order = buddy_order(page);
2636 move_to_free_list(page, zone, order, migratetype);
2638 pages_moved += 1 << order;
2644 int move_freepages_block(struct zone *zone, struct page *page,
2645 int migratetype, int *num_movable)
2647 unsigned long start_pfn, end_pfn, pfn;
2652 pfn = page_to_pfn(page);
2653 start_pfn = pageblock_start_pfn(pfn);
2654 end_pfn = pageblock_end_pfn(pfn) - 1;
2656 /* Do not cross zone boundaries */
2657 if (!zone_spans_pfn(zone, start_pfn))
2659 if (!zone_spans_pfn(zone, end_pfn))
2662 return move_freepages(zone, start_pfn, end_pfn, migratetype,
2666 static void change_pageblock_range(struct page *pageblock_page,
2667 int start_order, int migratetype)
2669 int nr_pageblocks = 1 << (start_order - pageblock_order);
2671 while (nr_pageblocks--) {
2672 set_pageblock_migratetype(pageblock_page, migratetype);
2673 pageblock_page += pageblock_nr_pages;
2678 * When we are falling back to another migratetype during allocation, try to
2679 * steal extra free pages from the same pageblocks to satisfy further
2680 * allocations, instead of polluting multiple pageblocks.
2682 * If we are stealing a relatively large buddy page, it is likely there will
2683 * be more free pages in the pageblock, so try to steal them all. For
2684 * reclaimable and unmovable allocations, we steal regardless of page size,
2685 * as fragmentation caused by those allocations polluting movable pageblocks
2686 * is worse than movable allocations stealing from unmovable and reclaimable
2689 static bool can_steal_fallback(unsigned int order, int start_mt)
2692 * Leaving this order check is intended, although there is
2693 * relaxed order check in next check. The reason is that
2694 * we can actually steal whole pageblock if this condition met,
2695 * but, below check doesn't guarantee it and that is just heuristic
2696 * so could be changed anytime.
2698 if (order >= pageblock_order)
2701 if (order >= pageblock_order / 2 ||
2702 start_mt == MIGRATE_RECLAIMABLE ||
2703 start_mt == MIGRATE_UNMOVABLE ||
2704 page_group_by_mobility_disabled)
2710 static inline bool boost_watermark(struct zone *zone)
2712 unsigned long max_boost;
2714 if (!watermark_boost_factor)
2717 * Don't bother in zones that are unlikely to produce results.
2718 * On small machines, including kdump capture kernels running
2719 * in a small area, boosting the watermark can cause an out of
2720 * memory situation immediately.
2722 if ((pageblock_nr_pages * 4) > zone_managed_pages(zone))
2725 max_boost = mult_frac(zone->_watermark[WMARK_HIGH],
2726 watermark_boost_factor, 10000);
2729 * high watermark may be uninitialised if fragmentation occurs
2730 * very early in boot so do not boost. We do not fall
2731 * through and boost by pageblock_nr_pages as failing
2732 * allocations that early means that reclaim is not going
2733 * to help and it may even be impossible to reclaim the
2734 * boosted watermark resulting in a hang.
2739 max_boost = max(pageblock_nr_pages, max_boost);
2741 zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages,
2748 * This function implements actual steal behaviour. If order is large enough,
2749 * we can steal whole pageblock. If not, we first move freepages in this
2750 * pageblock to our migratetype and determine how many already-allocated pages
2751 * are there in the pageblock with a compatible migratetype. If at least half
2752 * of pages are free or compatible, we can change migratetype of the pageblock
2753 * itself, so pages freed in the future will be put on the correct free list.
2755 static void steal_suitable_fallback(struct zone *zone, struct page *page,
2756 unsigned int alloc_flags, int start_type, bool whole_block)
2758 unsigned int current_order = buddy_order(page);
2759 int free_pages, movable_pages, alike_pages;
2762 old_block_type = get_pageblock_migratetype(page);
2765 * This can happen due to races and we want to prevent broken
2766 * highatomic accounting.
2768 if (is_migrate_highatomic(old_block_type))
2771 /* Take ownership for orders >= pageblock_order */
2772 if (current_order >= pageblock_order) {
2773 change_pageblock_range(page, current_order, start_type);
2778 * Boost watermarks to increase reclaim pressure to reduce the
2779 * likelihood of future fallbacks. Wake kswapd now as the node
2780 * may be balanced overall and kswapd will not wake naturally.
2782 if (boost_watermark(zone) && (alloc_flags & ALLOC_KSWAPD))
2783 set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
2785 /* We are not allowed to try stealing from the whole block */
2789 free_pages = move_freepages_block(zone, page, start_type,
2792 * Determine how many pages are compatible with our allocation.
2793 * For movable allocation, it's the number of movable pages which
2794 * we just obtained. For other types it's a bit more tricky.
2796 if (start_type == MIGRATE_MOVABLE) {
2797 alike_pages = movable_pages;
2800 * If we are falling back a RECLAIMABLE or UNMOVABLE allocation
2801 * to MOVABLE pageblock, consider all non-movable pages as
2802 * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or
2803 * vice versa, be conservative since we can't distinguish the
2804 * exact migratetype of non-movable pages.
2806 if (old_block_type == MIGRATE_MOVABLE)
2807 alike_pages = pageblock_nr_pages
2808 - (free_pages + movable_pages);
2813 /* moving whole block can fail due to zone boundary conditions */
2818 * If a sufficient number of pages in the block are either free or of
2819 * comparable migratability as our allocation, claim the whole block.
2821 if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||
2822 page_group_by_mobility_disabled)
2823 set_pageblock_migratetype(page, start_type);
2828 move_to_free_list(page, zone, current_order, start_type);
2832 * Check whether there is a suitable fallback freepage with requested order.
2833 * If only_stealable is true, this function returns fallback_mt only if
2834 * we can steal other freepages all together. This would help to reduce
2835 * fragmentation due to mixed migratetype pages in one pageblock.
2837 int find_suitable_fallback(struct free_area *area, unsigned int order,
2838 int migratetype, bool only_stealable, bool *can_steal)
2843 if (area->nr_free == 0)
2848 fallback_mt = fallbacks[migratetype][i];
2849 if (fallback_mt == MIGRATE_TYPES)
2852 if (free_area_empty(area, fallback_mt))
2855 if (can_steal_fallback(order, migratetype))
2858 if (!only_stealable)
2869 * Reserve a pageblock for exclusive use of high-order atomic allocations if
2870 * there are no empty page blocks that contain a page with a suitable order
2872 static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
2873 unsigned int alloc_order)
2876 unsigned long max_managed, flags;
2879 * Limit the number reserved to 1 pageblock or roughly 1% of a zone.
2880 * Check is race-prone but harmless.
2882 max_managed = (zone_managed_pages(zone) / 100) + pageblock_nr_pages;
2883 if (zone->nr_reserved_highatomic >= max_managed)
2886 spin_lock_irqsave(&zone->lock, flags);
2888 /* Recheck the nr_reserved_highatomic limit under the lock */
2889 if (zone->nr_reserved_highatomic >= max_managed)
2893 mt = get_pageblock_migratetype(page);
2894 /* Only reserve normal pageblocks (i.e., they can merge with others) */
2895 if (migratetype_is_mergeable(mt)) {
2896 zone->nr_reserved_highatomic += pageblock_nr_pages;
2897 set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
2898 move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL);
2902 spin_unlock_irqrestore(&zone->lock, flags);
2906 * Used when an allocation is about to fail under memory pressure. This
2907 * potentially hurts the reliability of high-order allocations when under
2908 * intense memory pressure but failed atomic allocations should be easier
2909 * to recover from than an OOM.
2911 * If @force is true, try to unreserve a pageblock even though highatomic
2912 * pageblock is exhausted.
2914 static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
2917 struct zonelist *zonelist = ac->zonelist;
2918 unsigned long flags;
2925 for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->highest_zoneidx,
2928 * Preserve at least one pageblock unless memory pressure
2931 if (!force && zone->nr_reserved_highatomic <=
2935 spin_lock_irqsave(&zone->lock, flags);
2936 for (order = 0; order < MAX_ORDER; order++) {
2937 struct free_area *area = &(zone->free_area[order]);
2939 page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
2944 * In page freeing path, migratetype change is racy so
2945 * we can counter several free pages in a pageblock
2946 * in this loop although we changed the pageblock type
2947 * from highatomic to ac->migratetype. So we should
2948 * adjust the count once.
2950 if (is_migrate_highatomic_page(page)) {
2952 * It should never happen but changes to
2953 * locking could inadvertently allow a per-cpu
2954 * drain to add pages to MIGRATE_HIGHATOMIC
2955 * while unreserving so be safe and watch for
2958 zone->nr_reserved_highatomic -= min(
2960 zone->nr_reserved_highatomic);
2964 * Convert to ac->migratetype and avoid the normal
2965 * pageblock stealing heuristics. Minimally, the caller
2966 * is doing the work and needs the pages. More
2967 * importantly, if the block was always converted to
2968 * MIGRATE_UNMOVABLE or another type then the number
2969 * of pageblocks that cannot be completely freed
2972 set_pageblock_migratetype(page, ac->migratetype);
2973 ret = move_freepages_block(zone, page, ac->migratetype,
2976 spin_unlock_irqrestore(&zone->lock, flags);
2980 spin_unlock_irqrestore(&zone->lock, flags);
2987 * Try finding a free buddy page on the fallback list and put it on the free
2988 * list of requested migratetype, possibly along with other pages from the same
2989 * block, depending on fragmentation avoidance heuristics. Returns true if
2990 * fallback was found so that __rmqueue_smallest() can grab it.
2992 * The use of signed ints for order and current_order is a deliberate
2993 * deviation from the rest of this file, to make the for loop
2994 * condition simpler.
2996 static __always_inline bool
2997 __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
2998 unsigned int alloc_flags)
3000 struct free_area *area;
3002 int min_order = order;
3008 * Do not steal pages from freelists belonging to other pageblocks
3009 * i.e. orders < pageblock_order. If there are no local zones free,
3010 * the zonelists will be reiterated without ALLOC_NOFRAGMENT.
3012 if (order < pageblock_order && alloc_flags & ALLOC_NOFRAGMENT)
3013 min_order = pageblock_order;
3016 * Find the largest available free page in the other list. This roughly
3017 * approximates finding the pageblock with the most free pages, which
3018 * would be too costly to do exactly.
3020 for (current_order = MAX_ORDER - 1; current_order >= min_order;
3022 area = &(zone->free_area[current_order]);
3023 fallback_mt = find_suitable_fallback(area, current_order,
3024 start_migratetype, false, &can_steal);
3025 if (fallback_mt == -1)
3029 * We cannot steal all free pages from the pageblock and the
3030 * requested migratetype is movable. In that case it's better to
3031 * steal and split the smallest available page instead of the
3032 * largest available page, because even if the next movable
3033 * allocation falls back into a different pageblock than this
3034 * one, it won't cause permanent fragmentation.
3036 if (!can_steal && start_migratetype == MIGRATE_MOVABLE
3037 && current_order > order)
3046 for (current_order = order; current_order < MAX_ORDER;
3048 area = &(zone->free_area[current_order]);
3049 fallback_mt = find_suitable_fallback(area, current_order,
3050 start_migratetype, false, &can_steal);
3051 if (fallback_mt != -1)
3056 * This should not happen - we already found a suitable fallback
3057 * when looking for the largest page.
3059 VM_BUG_ON(current_order == MAX_ORDER);
3062 page = get_page_from_free_area(area, fallback_mt);
3064 steal_suitable_fallback(zone, page, alloc_flags, start_migratetype,
3067 trace_mm_page_alloc_extfrag(page, order, current_order,
3068 start_migratetype, fallback_mt);
3075 * Do the hard work of removing an element from the buddy allocator.
3076 * Call me with the zone->lock already held.
3078 static __always_inline struct page *
3079 __rmqueue(struct zone *zone, unsigned int order, int migratetype,
3080 unsigned int alloc_flags)
3084 if (IS_ENABLED(CONFIG_CMA)) {
3086 * Balance movable allocations between regular and CMA areas by
3087 * allocating from CMA when over half of the zone's free memory
3088 * is in the CMA area.
3090 if (alloc_flags & ALLOC_CMA &&
3091 zone_page_state(zone, NR_FREE_CMA_PAGES) >
3092 zone_page_state(zone, NR_FREE_PAGES) / 2) {
3093 page = __rmqueue_cma_fallback(zone, order);
3099 page = __rmqueue_smallest(zone, order, migratetype);
3100 if (unlikely(!page)) {
3101 if (alloc_flags & ALLOC_CMA)
3102 page = __rmqueue_cma_fallback(zone, order);
3104 if (!page && __rmqueue_fallback(zone, order, migratetype,
3112 * Obtain a specified number of elements from the buddy allocator, all under
3113 * a single hold of the lock, for efficiency. Add them to the supplied list.
3114 * Returns the number of new pages which were placed at *list.
3116 static int rmqueue_bulk(struct zone *zone, unsigned int order,
3117 unsigned long count, struct list_head *list,
3118 int migratetype, unsigned int alloc_flags)
3120 unsigned long flags;
3121 int i, allocated = 0;
3123 spin_lock_irqsave(&zone->lock, flags);
3124 for (i = 0; i < count; ++i) {
3125 struct page *page = __rmqueue(zone, order, migratetype,
3127 if (unlikely(page == NULL))
3130 if (unlikely(check_pcp_refill(page, order)))
3134 * Split buddy pages returned by expand() are received here in
3135 * physical page order. The page is added to the tail of
3136 * caller's list. From the callers perspective, the linked list
3137 * is ordered by page number under some conditions. This is
3138 * useful for IO devices that can forward direction from the
3139 * head, thus also in the physical page order. This is useful
3140 * for IO devices that can merge IO requests if the physical
3141 * pages are ordered properly.
3143 list_add_tail(&page->pcp_list, list);
3145 if (is_migrate_cma(get_pcppage_migratetype(page)))
3146 __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
3151 * i pages were removed from the buddy list even if some leak due
3152 * to check_pcp_refill failing so adjust NR_FREE_PAGES based
3153 * on i. Do not confuse with 'allocated' which is the number of
3154 * pages added to the pcp list.
3156 __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
3157 spin_unlock_irqrestore(&zone->lock, flags);
3163 * Called from the vmstat counter updater to drain pagesets of this
3164 * currently executing processor on remote nodes after they have
3167 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
3169 int to_drain, batch;
3171 batch = READ_ONCE(pcp->batch);
3172 to_drain = min(pcp->count, batch);
3174 spin_lock(&pcp->lock);
3175 free_pcppages_bulk(zone, to_drain, pcp, 0);
3176 spin_unlock(&pcp->lock);
3182 * Drain pcplists of the indicated processor and zone.
3184 static void drain_pages_zone(unsigned int cpu, struct zone *zone)
3186 struct per_cpu_pages *pcp;
3188 pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
3190 spin_lock(&pcp->lock);
3191 free_pcppages_bulk(zone, pcp->count, pcp, 0);
3192 spin_unlock(&pcp->lock);
3197 * Drain pcplists of all zones on the indicated processor.
3199 static void drain_pages(unsigned int cpu)
3203 for_each_populated_zone(zone) {
3204 drain_pages_zone(cpu, zone);
3209 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
3211 void drain_local_pages(struct zone *zone)
3213 int cpu = smp_processor_id();
3216 drain_pages_zone(cpu, zone);
3222 * The implementation of drain_all_pages(), exposing an extra parameter to
3223 * drain on all cpus.
3225 * drain_all_pages() is optimized to only execute on cpus where pcplists are
3226 * not empty. The check for non-emptiness can however race with a free to
3227 * pcplist that has not yet increased the pcp->count from 0 to 1. Callers
3228 * that need the guarantee that every CPU has drained can disable the
3229 * optimizing racy check.
3231 static void __drain_all_pages(struct zone *zone, bool force_all_cpus)
3236 * Allocate in the BSS so we won't require allocation in
3237 * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
3239 static cpumask_t cpus_with_pcps;
3242 * Do not drain if one is already in progress unless it's specific to
3243 * a zone. Such callers are primarily CMA and memory hotplug and need
3244 * the drain to be complete when the call returns.
3246 if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) {
3249 mutex_lock(&pcpu_drain_mutex);
3253 * We don't care about racing with CPU hotplug event
3254 * as offline notification will cause the notified
3255 * cpu to drain that CPU pcps and on_each_cpu_mask
3256 * disables preemption as part of its processing
3258 for_each_online_cpu(cpu) {
3259 struct per_cpu_pages *pcp;
3261 bool has_pcps = false;
3263 if (force_all_cpus) {
3265 * The pcp.count check is racy, some callers need a
3266 * guarantee that no cpu is missed.
3270 pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
3274 for_each_populated_zone(z) {
3275 pcp = per_cpu_ptr(z->per_cpu_pageset, cpu);
3284 cpumask_set_cpu(cpu, &cpus_with_pcps);
3286 cpumask_clear_cpu(cpu, &cpus_with_pcps);
3289 for_each_cpu(cpu, &cpus_with_pcps) {
3291 drain_pages_zone(cpu, zone);
3296 mutex_unlock(&pcpu_drain_mutex);
3300 * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
3302 * When zone parameter is non-NULL, spill just the single zone's pages.
3304 void drain_all_pages(struct zone *zone)
3306 __drain_all_pages(zone, false);
3309 #ifdef CONFIG_HIBERNATION
3312 * Touch the watchdog for every WD_PAGE_COUNT pages.
3314 #define WD_PAGE_COUNT (128*1024)
3316 void mark_free_pages(struct zone *zone)
3318 unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
3319 unsigned long flags;
3320 unsigned int order, t;
3323 if (zone_is_empty(zone))
3326 spin_lock_irqsave(&zone->lock, flags);
3328 max_zone_pfn = zone_end_pfn(zone);
3329 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
3330 if (pfn_valid(pfn)) {
3331 page = pfn_to_page(pfn);
3333 if (!--page_count) {
3334 touch_nmi_watchdog();
3335 page_count = WD_PAGE_COUNT;
3338 if (page_zone(page) != zone)
3341 if (!swsusp_page_is_forbidden(page))
3342 swsusp_unset_page_free(page);
3345 for_each_migratetype_order(order, t) {
3346 list_for_each_entry(page,
3347 &zone->free_area[order].free_list[t], buddy_list) {
3350 pfn = page_to_pfn(page);
3351 for (i = 0; i < (1UL << order); i++) {
3352 if (!--page_count) {
3353 touch_nmi_watchdog();
3354 page_count = WD_PAGE_COUNT;
3356 swsusp_set_page_free(pfn_to_page(pfn + i));
3360 spin_unlock_irqrestore(&zone->lock, flags);
3362 #endif /* CONFIG_PM */
3364 static bool free_unref_page_prepare(struct page *page, unsigned long pfn,
3369 if (!free_pcp_prepare(page, order))
3372 migratetype = get_pfnblock_migratetype(page, pfn);
3373 set_pcppage_migratetype(page, migratetype);
3377 static int nr_pcp_free(struct per_cpu_pages *pcp, int high, int batch,
3380 int min_nr_free, max_nr_free;
3382 /* Free everything if batch freeing high-order pages. */
3383 if (unlikely(free_high))
3386 /* Check for PCP disabled or boot pageset */
3387 if (unlikely(high < batch))
3390 /* Leave at least pcp->batch pages on the list */
3391 min_nr_free = batch;
3392 max_nr_free = high - batch;
3395 * Double the number of pages freed each time there is subsequent
3396 * freeing of pages without any allocation.
3398 batch <<= pcp->free_factor;
3399 if (batch < max_nr_free)
3401 batch = clamp(batch, min_nr_free, max_nr_free);
3406 static int nr_pcp_high(struct per_cpu_pages *pcp, struct zone *zone,
3409 int high = READ_ONCE(pcp->high);
3411 if (unlikely(!high || free_high))
3414 if (!test_bit(ZONE_RECLAIM_ACTIVE, &zone->flags))
3418 * If reclaim is active, limit the number of pages that can be
3419 * stored on pcp lists
3421 return min(READ_ONCE(pcp->batch) << 2, high);
3424 static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp,
3425 struct page *page, int migratetype,
3432 __count_vm_events(PGFREE, 1 << order);
3433 pindex = order_to_pindex(migratetype, order);
3434 list_add(&page->pcp_list, &pcp->lists[pindex]);
3435 pcp->count += 1 << order;
3438 * As high-order pages other than THP's stored on PCP can contribute
3439 * to fragmentation, limit the number stored when PCP is heavily
3440 * freeing without allocation. The remainder after bulk freeing
3441 * stops will be drained from vmstat refresh context.
3443 free_high = (pcp->free_factor && order && order <= PAGE_ALLOC_COSTLY_ORDER);
3445 high = nr_pcp_high(pcp, zone, free_high);
3446 if (pcp->count >= high) {
3447 int batch = READ_ONCE(pcp->batch);
3449 free_pcppages_bulk(zone, nr_pcp_free(pcp, high, batch, free_high), pcp, pindex);
3456 void free_unref_page(struct page *page, unsigned int order)
3458 unsigned long __maybe_unused UP_flags;
3459 struct per_cpu_pages *pcp;
3461 unsigned long pfn = page_to_pfn(page);
3464 if (!free_unref_page_prepare(page, pfn, order))
3468 * We only track unmovable, reclaimable and movable on pcp lists.
3469 * Place ISOLATE pages on the isolated list because they are being
3470 * offlined but treat HIGHATOMIC as movable pages so we can get those
3471 * areas back if necessary. Otherwise, we may have to free
3472 * excessively into the page allocator
3474 migratetype = get_pcppage_migratetype(page);
3475 if (unlikely(migratetype >= MIGRATE_PCPTYPES)) {
3476 if (unlikely(is_migrate_isolate(migratetype))) {
3477 free_one_page(page_zone(page), page, pfn, order, migratetype, FPI_NONE);
3480 migratetype = MIGRATE_MOVABLE;
3483 zone = page_zone(page);
3484 pcp_trylock_prepare(UP_flags);
3485 pcp = pcp_spin_trylock(zone->per_cpu_pageset);
3487 free_unref_page_commit(zone, pcp, page, migratetype, order);
3488 pcp_spin_unlock(pcp);
3490 free_one_page(zone, page, pfn, order, migratetype, FPI_NONE);
3492 pcp_trylock_finish(UP_flags);
3496 * Free a list of 0-order pages
3498 void free_unref_page_list(struct list_head *list)
3500 unsigned long __maybe_unused UP_flags;
3501 struct page *page, *next;
3502 struct per_cpu_pages *pcp = NULL;
3503 struct zone *locked_zone = NULL;
3504 int batch_count = 0;
3507 /* Prepare pages for freeing */
3508 list_for_each_entry_safe(page, next, list, lru) {
3509 unsigned long pfn = page_to_pfn(page);
3510 if (!free_unref_page_prepare(page, pfn, 0)) {
3511 list_del(&page->lru);
3516 * Free isolated pages directly to the allocator, see
3517 * comment in free_unref_page.
3519 migratetype = get_pcppage_migratetype(page);
3520 if (unlikely(is_migrate_isolate(migratetype))) {
3521 list_del(&page->lru);
3522 free_one_page(page_zone(page), page, pfn, 0, migratetype, FPI_NONE);
3527 list_for_each_entry_safe(page, next, list, lru) {
3528 struct zone *zone = page_zone(page);
3530 list_del(&page->lru);
3531 migratetype = get_pcppage_migratetype(page);
3534 * Either different zone requiring a different pcp lock or
3535 * excessive lock hold times when freeing a large list of
3538 if (zone != locked_zone || batch_count == SWAP_CLUSTER_MAX) {
3540 pcp_spin_unlock(pcp);
3541 pcp_trylock_finish(UP_flags);
3547 * trylock is necessary as pages may be getting freed
3548 * from IRQ or SoftIRQ context after an IO completion.
3550 pcp_trylock_prepare(UP_flags);
3551 pcp = pcp_spin_trylock(zone->per_cpu_pageset);
3552 if (unlikely(!pcp)) {
3553 pcp_trylock_finish(UP_flags);
3554 free_one_page(zone, page, page_to_pfn(page),
3555 0, migratetype, FPI_NONE);
3563 * Non-isolated types over MIGRATE_PCPTYPES get added
3564 * to the MIGRATE_MOVABLE pcp list.
3566 if (unlikely(migratetype >= MIGRATE_PCPTYPES))
3567 migratetype = MIGRATE_MOVABLE;
3569 trace_mm_page_free_batched(page);
3570 free_unref_page_commit(zone, pcp, page, migratetype, 0);
3575 pcp_spin_unlock(pcp);
3576 pcp_trylock_finish(UP_flags);
3581 * split_page takes a non-compound higher-order page, and splits it into
3582 * n (1<<order) sub-pages: page[0..n]
3583 * Each sub-page must be freed individually.
3585 * Note: this is probably too low level an operation for use in drivers.
3586 * Please consult with lkml before using this in your driver.
3588 void split_page(struct page *page, unsigned int order)
3592 VM_BUG_ON_PAGE(PageCompound(page), page);
3593 VM_BUG_ON_PAGE(!page_count(page), page);
3595 for (i = 1; i < (1 << order); i++)
3596 set_page_refcounted(page + i);
3597 split_page_owner(page, 1 << order);
3598 split_page_memcg(page, 1 << order);
3600 EXPORT_SYMBOL_GPL(split_page);
3602 int __isolate_free_page(struct page *page, unsigned int order)
3604 struct zone *zone = page_zone(page);
3605 int mt = get_pageblock_migratetype(page);
3607 if (!is_migrate_isolate(mt)) {
3608 unsigned long watermark;
3610 * Obey watermarks as if the page was being allocated. We can
3611 * emulate a high-order watermark check with a raised order-0
3612 * watermark, because we already know our high-order page
3615 watermark = zone->_watermark[WMARK_MIN] + (1UL << order);
3616 if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
3619 __mod_zone_freepage_state(zone, -(1UL << order), mt);
3622 del_page_from_free_list(page, zone, order);
3625 * Set the pageblock if the isolated page is at least half of a
3628 if (order >= pageblock_order - 1) {
3629 struct page *endpage = page + (1 << order) - 1;
3630 for (; page < endpage; page += pageblock_nr_pages) {
3631 int mt = get_pageblock_migratetype(page);
3633 * Only change normal pageblocks (i.e., they can merge
3636 if (migratetype_is_mergeable(mt))
3637 set_pageblock_migratetype(page,
3642 return 1UL << order;
3646 * __putback_isolated_page - Return a now-isolated page back where we got it
3647 * @page: Page that was isolated
3648 * @order: Order of the isolated page
3649 * @mt: The page's pageblock's migratetype
3651 * This function is meant to return a page pulled from the free lists via
3652 * __isolate_free_page back to the free lists they were pulled from.
3654 void __putback_isolated_page(struct page *page, unsigned int order, int mt)
3656 struct zone *zone = page_zone(page);
3658 /* zone lock should be held when this function is called */
3659 lockdep_assert_held(&zone->lock);
3661 /* Return isolated page to tail of freelist. */
3662 __free_one_page(page, page_to_pfn(page), zone, order, mt,
3663 FPI_SKIP_REPORT_NOTIFY | FPI_TO_TAIL);
3667 * Update NUMA hit/miss statistics
3669 static inline void zone_statistics(struct zone *preferred_zone, struct zone *z,
3673 enum numa_stat_item local_stat = NUMA_LOCAL;
3675 /* skip numa counters update if numa stats is disabled */
3676 if (!static_branch_likely(&vm_numa_stat_key))
3679 if (zone_to_nid(z) != numa_node_id())
3680 local_stat = NUMA_OTHER;
3682 if (zone_to_nid(z) == zone_to_nid(preferred_zone))
3683 __count_numa_events(z, NUMA_HIT, nr_account);
3685 __count_numa_events(z, NUMA_MISS, nr_account);
3686 __count_numa_events(preferred_zone, NUMA_FOREIGN, nr_account);
3688 __count_numa_events(z, local_stat, nr_account);
3692 static __always_inline
3693 struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone,
3694 unsigned int order, unsigned int alloc_flags,
3698 unsigned long flags;
3702 spin_lock_irqsave(&zone->lock, flags);
3704 * order-0 request can reach here when the pcplist is skipped
3705 * due to non-CMA allocation context. HIGHATOMIC area is
3706 * reserved for high-order atomic allocation, so order-0
3707 * request should skip it.
3709 if (order > 0 && alloc_flags & ALLOC_HARDER)
3710 page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
3712 page = __rmqueue(zone, order, migratetype, alloc_flags);
3714 spin_unlock_irqrestore(&zone->lock, flags);
3718 __mod_zone_freepage_state(zone, -(1 << order),
3719 get_pcppage_migratetype(page));
3720 spin_unlock_irqrestore(&zone->lock, flags);
3721 } while (check_new_pages(page, order));
3723 __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
3724 zone_statistics(preferred_zone, zone, 1);
3729 /* Remove page from the per-cpu list, caller must protect the list */
3731 struct page *__rmqueue_pcplist(struct zone *zone, unsigned int order,
3733 unsigned int alloc_flags,
3734 struct per_cpu_pages *pcp,
3735 struct list_head *list)
3740 if (list_empty(list)) {
3741 int batch = READ_ONCE(pcp->batch);
3745 * Scale batch relative to order if batch implies
3746 * free pages can be stored on the PCP. Batch can
3747 * be 1 for small zones or for boot pagesets which
3748 * should never store free pages as the pages may
3749 * belong to arbitrary zones.
3752 batch = max(batch >> order, 2);
3753 alloced = rmqueue_bulk(zone, order,
3755 migratetype, alloc_flags);
3757 pcp->count += alloced << order;
3758 if (unlikely(list_empty(list)))
3762 page = list_first_entry(list, struct page, pcp_list);
3763 list_del(&page->pcp_list);
3764 pcp->count -= 1 << order;
3765 } while (check_new_pcp(page, order));
3770 /* Lock and remove page from the per-cpu list */
3771 static struct page *rmqueue_pcplist(struct zone *preferred_zone,
3772 struct zone *zone, unsigned int order,
3773 int migratetype, unsigned int alloc_flags)
3775 struct per_cpu_pages *pcp;
3776 struct list_head *list;
3778 unsigned long __maybe_unused UP_flags;
3780 /* spin_trylock may fail due to a parallel drain or IRQ reentrancy. */
3781 pcp_trylock_prepare(UP_flags);
3782 pcp = pcp_spin_trylock(zone->per_cpu_pageset);
3784 pcp_trylock_finish(UP_flags);
3789 * On allocation, reduce the number of pages that are batch freed.
3790 * See nr_pcp_free() where free_factor is increased for subsequent
3793 pcp->free_factor >>= 1;
3794 list = &pcp->lists[order_to_pindex(migratetype, order)];
3795 page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags, pcp, list);
3796 pcp_spin_unlock(pcp);
3797 pcp_trylock_finish(UP_flags);
3799 __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
3800 zone_statistics(preferred_zone, zone, 1);
3806 * Allocate a page from the given zone.
3807 * Use pcplists for THP or "cheap" high-order allocations.
3811 * Do not instrument rmqueue() with KMSAN. This function may call
3812 * __msan_poison_alloca() through a call to set_pfnblock_flags_mask().
3813 * If __msan_poison_alloca() attempts to allocate pages for the stack depot, it
3814 * may call rmqueue() again, which will result in a deadlock.
3816 __no_sanitize_memory
3818 struct page *rmqueue(struct zone *preferred_zone,
3819 struct zone *zone, unsigned int order,
3820 gfp_t gfp_flags, unsigned int alloc_flags,
3826 * We most definitely don't want callers attempting to
3827 * allocate greater than order-1 page units with __GFP_NOFAIL.
3829 WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
3831 if (likely(pcp_allowed_order(order))) {
3833 * MIGRATE_MOVABLE pcplist could have the pages on CMA area and
3834 * we need to skip it when CMA area isn't allowed.
3836 if (!IS_ENABLED(CONFIG_CMA) || alloc_flags & ALLOC_CMA ||
3837 migratetype != MIGRATE_MOVABLE) {
3838 page = rmqueue_pcplist(preferred_zone, zone, order,
3839 migratetype, alloc_flags);
3845 page = rmqueue_buddy(preferred_zone, zone, order, alloc_flags,
3849 /* Separate test+clear to avoid unnecessary atomics */
3850 if (unlikely(test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags))) {
3851 clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
3852 wakeup_kswapd(zone, 0, 0, zone_idx(zone));
3855 VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
3859 #ifdef CONFIG_FAIL_PAGE_ALLOC
3862 struct fault_attr attr;
3864 bool ignore_gfp_highmem;
3865 bool ignore_gfp_reclaim;
3867 } fail_page_alloc = {
3868 .attr = FAULT_ATTR_INITIALIZER,
3869 .ignore_gfp_reclaim = true,
3870 .ignore_gfp_highmem = true,
3874 static int __init setup_fail_page_alloc(char *str)
3876 return setup_fault_attr(&fail_page_alloc.attr, str);
3878 __setup("fail_page_alloc=", setup_fail_page_alloc);
3880 static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3884 if (order < fail_page_alloc.min_order)
3886 if (gfp_mask & __GFP_NOFAIL)
3888 if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
3890 if (fail_page_alloc.ignore_gfp_reclaim &&
3891 (gfp_mask & __GFP_DIRECT_RECLAIM))
3894 /* See comment in __should_failslab() */
3895 if (gfp_mask & __GFP_NOWARN)
3896 flags |= FAULT_NOWARN;
3898 return should_fail_ex(&fail_page_alloc.attr, 1 << order, flags);
3901 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
3903 static int __init fail_page_alloc_debugfs(void)
3905 umode_t mode = S_IFREG | 0600;
3908 dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
3909 &fail_page_alloc.attr);
3911 debugfs_create_bool("ignore-gfp-wait", mode, dir,
3912 &fail_page_alloc.ignore_gfp_reclaim);
3913 debugfs_create_bool("ignore-gfp-highmem", mode, dir,
3914 &fail_page_alloc.ignore_gfp_highmem);
3915 debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);
3920 late_initcall(fail_page_alloc_debugfs);
3922 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
3924 #else /* CONFIG_FAIL_PAGE_ALLOC */
3926 static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3931 #endif /* CONFIG_FAIL_PAGE_ALLOC */
3933 noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3935 return __should_fail_alloc_page(gfp_mask, order);
3937 ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);
3939 static inline long __zone_watermark_unusable_free(struct zone *z,
3940 unsigned int order, unsigned int alloc_flags)
3942 const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM));
3943 long unusable_free = (1 << order) - 1;
3946 * If the caller does not have rights to ALLOC_HARDER then subtract
3947 * the high-atomic reserves. This will over-estimate the size of the
3948 * atomic reserve but it avoids a search.
3950 if (likely(!alloc_harder))
3951 unusable_free += z->nr_reserved_highatomic;
3954 /* If allocation can't use CMA areas don't use free CMA pages */
3955 if (!(alloc_flags & ALLOC_CMA))
3956 unusable_free += zone_page_state(z, NR_FREE_CMA_PAGES);
3959 return unusable_free;
3963 * Return true if free base pages are above 'mark'. For high-order checks it
3964 * will return true of the order-0 watermark is reached and there is at least
3965 * one free page of a suitable size. Checking now avoids taking the zone lock
3966 * to check in the allocation paths if no pages are free.
3968 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
3969 int highest_zoneidx, unsigned int alloc_flags,
3974 const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM));
3976 /* free_pages may go negative - that's OK */
3977 free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags);
3979 if (alloc_flags & ALLOC_HIGH)
3982 if (unlikely(alloc_harder)) {
3984 * OOM victims can try even harder than normal ALLOC_HARDER
3985 * users on the grounds that it's definitely going to be in
3986 * the exit path shortly and free memory. Any allocation it
3987 * makes during the free path will be small and short-lived.
3989 if (alloc_flags & ALLOC_OOM)
3996 * Check watermarks for an order-0 allocation request. If these
3997 * are not met, then a high-order request also cannot go ahead
3998 * even if a suitable page happened to be free.
4000 if (free_pages <= min + z->lowmem_reserve[highest_zoneidx])
4003 /* If this is an order-0 request then the watermark is fine */
4007 /* For a high-order request, check at least one suitable page is free */
4008 for (o = order; o < MAX_ORDER; o++) {
4009 struct free_area *area = &z->free_area[o];
4015 for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
4016 if (!free_area_empty(area, mt))
4021 if ((alloc_flags & ALLOC_CMA) &&
4022 !free_area_empty(area, MIGRATE_CMA)) {
4026 if (alloc_harder && !free_area_empty(area, MIGRATE_HIGHATOMIC))
4032 bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
4033 int highest_zoneidx, unsigned int alloc_flags)
4035 return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags,
4036 zone_page_state(z, NR_FREE_PAGES));
4039 static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
4040 unsigned long mark, int highest_zoneidx,
4041 unsigned int alloc_flags, gfp_t gfp_mask)
4045 free_pages = zone_page_state(z, NR_FREE_PAGES);
4048 * Fast check for order-0 only. If this fails then the reserves
4049 * need to be calculated.
4055 usable_free = free_pages;
4056 reserved = __zone_watermark_unusable_free(z, 0, alloc_flags);
4058 /* reserved may over estimate high-atomic reserves. */
4059 usable_free -= min(usable_free, reserved);
4060 if (usable_free > mark + z->lowmem_reserve[highest_zoneidx])
4064 if (__zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags,
4068 * Ignore watermark boosting for GFP_ATOMIC order-0 allocations
4069 * when checking the min watermark. The min watermark is the
4070 * point where boosting is ignored so that kswapd is woken up
4071 * when below the low watermark.
4073 if (unlikely(!order && (gfp_mask & __GFP_ATOMIC) && z->watermark_boost
4074 && ((alloc_flags & ALLOC_WMARK_MASK) == WMARK_MIN))) {
4075 mark = z->_watermark[WMARK_MIN];
4076 return __zone_watermark_ok(z, order, mark, highest_zoneidx,
4077 alloc_flags, free_pages);
4083 bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
4084 unsigned long mark, int highest_zoneidx)
4086 long free_pages = zone_page_state(z, NR_FREE_PAGES);
4088 if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
4089 free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
4091 return __zone_watermark_ok(z, order, mark, highest_zoneidx, 0,
4096 int __read_mostly node_reclaim_distance = RECLAIM_DISTANCE;
4098 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
4100 return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <=
4101 node_reclaim_distance;
4103 #else /* CONFIG_NUMA */
4104 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
4108 #endif /* CONFIG_NUMA */
4111 * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid
4112 * fragmentation is subtle. If the preferred zone was HIGHMEM then
4113 * premature use of a lower zone may cause lowmem pressure problems that
4114 * are worse than fragmentation. If the next zone is ZONE_DMA then it is
4115 * probably too small. It only makes sense to spread allocations to avoid
4116 * fragmentation between the Normal and DMA32 zones.
4118 static inline unsigned int
4119 alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
4121 unsigned int alloc_flags;
4124 * __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
4127 alloc_flags = (__force int) (gfp_mask & __GFP_KSWAPD_RECLAIM);
4129 #ifdef CONFIG_ZONE_DMA32
4133 if (zone_idx(zone) != ZONE_NORMAL)
4137 * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and
4138 * the pointer is within zone->zone_pgdat->node_zones[]. Also assume
4139 * on UMA that if Normal is populated then so is DMA32.
4141 BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1);
4142 if (nr_online_nodes > 1 && !populated_zone(--zone))
4145 alloc_flags |= ALLOC_NOFRAGMENT;
4146 #endif /* CONFIG_ZONE_DMA32 */
4150 /* Must be called after current_gfp_context() which can change gfp_mask */
4151 static inline unsigned int gfp_to_alloc_flags_cma(gfp_t gfp_mask,
4152 unsigned int alloc_flags)
4155 if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE)
4156 alloc_flags |= ALLOC_CMA;
4162 * get_page_from_freelist goes through the zonelist trying to allocate
4165 static struct page *
4166 get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
4167 const struct alloc_context *ac)
4171 struct pglist_data *last_pgdat = NULL;
4172 bool last_pgdat_dirty_ok = false;
4177 * Scan zonelist, looking for a zone with enough free.
4178 * See also __cpuset_node_allowed() comment in kernel/cgroup/cpuset.c.
4180 no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
4181 z = ac->preferred_zoneref;
4182 for_next_zone_zonelist_nodemask(zone, z, ac->highest_zoneidx,
4187 if (cpusets_enabled() &&
4188 (alloc_flags & ALLOC_CPUSET) &&
4189 !__cpuset_zone_allowed(zone, gfp_mask))
4192 * When allocating a page cache page for writing, we
4193 * want to get it from a node that is within its dirty
4194 * limit, such that no single node holds more than its
4195 * proportional share of globally allowed dirty pages.
4196 * The dirty limits take into account the node's
4197 * lowmem reserves and high watermark so that kswapd
4198 * should be able to balance it without having to
4199 * write pages from its LRU list.
4201 * XXX: For now, allow allocations to potentially
4202 * exceed the per-node dirty limit in the slowpath
4203 * (spread_dirty_pages unset) before going into reclaim,
4204 * which is important when on a NUMA setup the allowed
4205 * nodes are together not big enough to reach the
4206 * global limit. The proper fix for these situations
4207 * will require awareness of nodes in the
4208 * dirty-throttling and the flusher threads.
4210 if (ac->spread_dirty_pages) {
4211 if (last_pgdat != zone->zone_pgdat) {
4212 last_pgdat = zone->zone_pgdat;
4213 last_pgdat_dirty_ok = node_dirty_ok(zone->zone_pgdat);
4216 if (!last_pgdat_dirty_ok)
4220 if (no_fallback && nr_online_nodes > 1 &&
4221 zone != ac->preferred_zoneref->zone) {
4225 * If moving to a remote node, retry but allow
4226 * fragmenting fallbacks. Locality is more important
4227 * than fragmentation avoidance.
4229 local_nid = zone_to_nid(ac->preferred_zoneref->zone);
4230 if (zone_to_nid(zone) != local_nid) {
4231 alloc_flags &= ~ALLOC_NOFRAGMENT;
4236 mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
4237 if (!zone_watermark_fast(zone, order, mark,
4238 ac->highest_zoneidx, alloc_flags,
4242 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
4244 * Watermark failed for this zone, but see if we can
4245 * grow this zone if it contains deferred pages.
4247 if (static_branch_unlikely(&deferred_pages)) {
4248 if (_deferred_grow_zone(zone, order))
4252 /* Checked here to keep the fast path fast */
4253 BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
4254 if (alloc_flags & ALLOC_NO_WATERMARKS)
4257 if (!node_reclaim_enabled() ||
4258 !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
4261 ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
4263 case NODE_RECLAIM_NOSCAN:
4266 case NODE_RECLAIM_FULL:
4267 /* scanned but unreclaimable */
4270 /* did we reclaim enough */
4271 if (zone_watermark_ok(zone, order, mark,
4272 ac->highest_zoneidx, alloc_flags))
4280 page = rmqueue(ac->preferred_zoneref->zone, zone, order,
4281 gfp_mask, alloc_flags, ac->migratetype);
4283 prep_new_page(page, order, gfp_mask, alloc_flags);
4286 * If this is a high-order atomic allocation then check
4287 * if the pageblock should be reserved for the future
4289 if (unlikely(order && (alloc_flags & ALLOC_HARDER)))
4290 reserve_highatomic_pageblock(page, zone, order);
4294 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
4295 /* Try again if zone has deferred pages */
4296 if (static_branch_unlikely(&deferred_pages)) {
4297 if (_deferred_grow_zone(zone, order))
4305 * It's possible on a UMA machine to get through all zones that are
4306 * fragmented. If avoiding fragmentation, reset and try again.
4309 alloc_flags &= ~ALLOC_NOFRAGMENT;
4316 static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask)
4318 unsigned int filter = SHOW_MEM_FILTER_NODES;
4321 * This documents exceptions given to allocations in certain
4322 * contexts that are allowed to allocate outside current's set
4325 if (!(gfp_mask & __GFP_NOMEMALLOC))
4326 if (tsk_is_oom_victim(current) ||
4327 (current->flags & (PF_MEMALLOC | PF_EXITING)))
4328 filter &= ~SHOW_MEM_FILTER_NODES;
4329 if (!in_task() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
4330 filter &= ~SHOW_MEM_FILTER_NODES;
4332 __show_mem(filter, nodemask, gfp_zone(gfp_mask));
4335 void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)
4337 struct va_format vaf;
4339 static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1);
4341 if ((gfp_mask & __GFP_NOWARN) ||
4342 !__ratelimit(&nopage_rs) ||
4343 ((gfp_mask & __GFP_DMA) && !has_managed_dma()))
4346 va_start(args, fmt);
4349 pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl",
4350 current->comm, &vaf, gfp_mask, &gfp_mask,
4351 nodemask_pr_args(nodemask));
4354 cpuset_print_current_mems_allowed();
4357 warn_alloc_show_mem(gfp_mask, nodemask);
4360 static inline struct page *
4361 __alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order,
4362 unsigned int alloc_flags,
4363 const struct alloc_context *ac)
4367 page = get_page_from_freelist(gfp_mask, order,
4368 alloc_flags|ALLOC_CPUSET, ac);
4370 * fallback to ignore cpuset restriction if our nodes
4374 page = get_page_from_freelist(gfp_mask, order,
4380 static inline struct page *
4381 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
4382 const struct alloc_context *ac, unsigned long *did_some_progress)
4384 struct oom_control oc = {
4385 .zonelist = ac->zonelist,
4386 .nodemask = ac->nodemask,
4388 .gfp_mask = gfp_mask,
4393 *did_some_progress = 0;
4396 * Acquire the oom lock. If that fails, somebody else is
4397 * making progress for us.
4399 if (!mutex_trylock(&oom_lock)) {
4400 *did_some_progress = 1;
4401 schedule_timeout_uninterruptible(1);
4406 * Go through the zonelist yet one more time, keep very high watermark
4407 * here, this is only to catch a parallel oom killing, we must fail if
4408 * we're still under heavy pressure. But make sure that this reclaim
4409 * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY
4410 * allocation which will never fail due to oom_lock already held.
4412 page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) &
4413 ~__GFP_DIRECT_RECLAIM, order,
4414 ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
4418 /* Coredumps can quickly deplete all memory reserves */
4419 if (current->flags & PF_DUMPCORE)
4421 /* The OOM killer will not help higher order allocs */
4422 if (order > PAGE_ALLOC_COSTLY_ORDER)
4425 * We have already exhausted all our reclaim opportunities without any
4426 * success so it is time to admit defeat. We will skip the OOM killer
4427 * because it is very likely that the caller has a more reasonable
4428 * fallback than shooting a random task.
4430 * The OOM killer may not free memory on a specific node.
4432 if (gfp_mask & (__GFP_RETRY_MAYFAIL | __GFP_THISNODE))
4434 /* The OOM killer does not needlessly kill tasks for lowmem */
4435 if (ac->highest_zoneidx < ZONE_NORMAL)
4437 if (pm_suspended_storage())
4440 * XXX: GFP_NOFS allocations should rather fail than rely on
4441 * other request to make a forward progress.
4442 * We are in an unfortunate situation where out_of_memory cannot
4443 * do much for this context but let's try it to at least get
4444 * access to memory reserved if the current task is killed (see
4445 * out_of_memory). Once filesystems are ready to handle allocation
4446 * failures more gracefully we should just bail out here.
4449 /* Exhausted what can be done so it's blame time */
4450 if (out_of_memory(&oc) ||
4451 WARN_ON_ONCE_GFP(gfp_mask & __GFP_NOFAIL, gfp_mask)) {
4452 *did_some_progress = 1;
4455 * Help non-failing allocations by giving them access to memory
4458 if (gfp_mask & __GFP_NOFAIL)
4459 page = __alloc_pages_cpuset_fallback(gfp_mask, order,
4460 ALLOC_NO_WATERMARKS, ac);
4463 mutex_unlock(&oom_lock);
4468 * Maximum number of compaction retries with a progress before OOM
4469 * killer is consider as the only way to move forward.
4471 #define MAX_COMPACT_RETRIES 16
4473 #ifdef CONFIG_COMPACTION
4474 /* Try memory compaction for high-order allocations before reclaim */
4475 static struct page *
4476 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
4477 unsigned int alloc_flags, const struct alloc_context *ac,
4478 enum compact_priority prio, enum compact_result *compact_result)
4480 struct page *page = NULL;
4481 unsigned long pflags;
4482 unsigned int noreclaim_flag;
4487 psi_memstall_enter(&pflags);
4488 delayacct_compact_start();
4489 noreclaim_flag = memalloc_noreclaim_save();
4491 *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
4494 memalloc_noreclaim_restore(noreclaim_flag);
4495 psi_memstall_leave(&pflags);
4496 delayacct_compact_end();
4498 if (*compact_result == COMPACT_SKIPPED)
4501 * At least in one zone compaction wasn't deferred or skipped, so let's
4502 * count a compaction stall
4504 count_vm_event(COMPACTSTALL);
4506 /* Prep a captured page if available */
4508 prep_new_page(page, order, gfp_mask, alloc_flags);
4510 /* Try get a page from the freelist if available */
4512 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4515 struct zone *zone = page_zone(page);
4517 zone->compact_blockskip_flush = false;
4518 compaction_defer_reset(zone, order, true);
4519 count_vm_event(COMPACTSUCCESS);
4524 * It's bad if compaction run occurs and fails. The most likely reason
4525 * is that pages exist, but not enough to satisfy watermarks.
4527 count_vm_event(COMPACTFAIL);
4535 should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
4536 enum compact_result compact_result,
4537 enum compact_priority *compact_priority,
4538 int *compaction_retries)
4540 int max_retries = MAX_COMPACT_RETRIES;
4543 int retries = *compaction_retries;
4544 enum compact_priority priority = *compact_priority;
4549 if (fatal_signal_pending(current))
4552 if (compaction_made_progress(compact_result))
4553 (*compaction_retries)++;
4556 * compaction considers all the zone as desperately out of memory
4557 * so it doesn't really make much sense to retry except when the
4558 * failure could be caused by insufficient priority
4560 if (compaction_failed(compact_result))
4561 goto check_priority;
4564 * compaction was skipped because there are not enough order-0 pages
4565 * to work with, so we retry only if it looks like reclaim can help.
4567 if (compaction_needs_reclaim(compact_result)) {
4568 ret = compaction_zonelist_suitable(ac, order, alloc_flags);
4573 * make sure the compaction wasn't deferred or didn't bail out early
4574 * due to locks contention before we declare that we should give up.
4575 * But the next retry should use a higher priority if allowed, so
4576 * we don't just keep bailing out endlessly.
4578 if (compaction_withdrawn(compact_result)) {
4579 goto check_priority;
4583 * !costly requests are much more important than __GFP_RETRY_MAYFAIL
4584 * costly ones because they are de facto nofail and invoke OOM
4585 * killer to move on while costly can fail and users are ready
4586 * to cope with that. 1/4 retries is rather arbitrary but we
4587 * would need much more detailed feedback from compaction to
4588 * make a better decision.
4590 if (order > PAGE_ALLOC_COSTLY_ORDER)
4592 if (*compaction_retries <= max_retries) {
4598 * Make sure there are attempts at the highest priority if we exhausted
4599 * all retries or failed at the lower priorities.
4602 min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ?
4603 MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;
4605 if (*compact_priority > min_priority) {
4606 (*compact_priority)--;
4607 *compaction_retries = 0;
4611 trace_compact_retry(order, priority, compact_result, retries, max_retries, ret);
4615 static inline struct page *
4616 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
4617 unsigned int alloc_flags, const struct alloc_context *ac,
4618 enum compact_priority prio, enum compact_result *compact_result)
4620 *compact_result = COMPACT_SKIPPED;
4625 should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
4626 enum compact_result compact_result,
4627 enum compact_priority *compact_priority,
4628 int *compaction_retries)
4633 if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
4637 * There are setups with compaction disabled which would prefer to loop
4638 * inside the allocator rather than hit the oom killer prematurely.
4639 * Let's give them a good hope and keep retrying while the order-0
4640 * watermarks are OK.
4642 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
4643 ac->highest_zoneidx, ac->nodemask) {
4644 if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
4645 ac->highest_zoneidx, alloc_flags))
4650 #endif /* CONFIG_COMPACTION */
4652 #ifdef CONFIG_LOCKDEP
4653 static struct lockdep_map __fs_reclaim_map =
4654 STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map);
4656 static bool __need_reclaim(gfp_t gfp_mask)
4658 /* no reclaim without waiting on it */
4659 if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
4662 /* this guy won't enter reclaim */
4663 if (current->flags & PF_MEMALLOC)
4666 if (gfp_mask & __GFP_NOLOCKDEP)
4672 void __fs_reclaim_acquire(unsigned long ip)
4674 lock_acquire_exclusive(&__fs_reclaim_map, 0, 0, NULL, ip);
4677 void __fs_reclaim_release(unsigned long ip)
4679 lock_release(&__fs_reclaim_map, ip);
4682 void fs_reclaim_acquire(gfp_t gfp_mask)
4684 gfp_mask = current_gfp_context(gfp_mask);
4686 if (__need_reclaim(gfp_mask)) {
4687 if (gfp_mask & __GFP_FS)
4688 __fs_reclaim_acquire(_RET_IP_);
4690 #ifdef CONFIG_MMU_NOTIFIER
4691 lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
4692 lock_map_release(&__mmu_notifier_invalidate_range_start_map);
4697 EXPORT_SYMBOL_GPL(fs_reclaim_acquire);
4699 void fs_reclaim_release(gfp_t gfp_mask)
4701 gfp_mask = current_gfp_context(gfp_mask);
4703 if (__need_reclaim(gfp_mask)) {
4704 if (gfp_mask & __GFP_FS)
4705 __fs_reclaim_release(_RET_IP_);
4708 EXPORT_SYMBOL_GPL(fs_reclaim_release);
4712 * Zonelists may change due to hotplug during allocation. Detect when zonelists
4713 * have been rebuilt so allocation retries. Reader side does not lock and
4714 * retries the allocation if zonelist changes. Writer side is protected by the
4715 * embedded spin_lock.
4717 static DEFINE_SEQLOCK(zonelist_update_seq);
4719 static unsigned int zonelist_iter_begin(void)
4721 if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
4722 return read_seqbegin(&zonelist_update_seq);
4727 static unsigned int check_retry_zonelist(unsigned int seq)
4729 if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
4730 return read_seqretry(&zonelist_update_seq, seq);
4735 /* Perform direct synchronous page reclaim */
4736 static unsigned long
4737 __perform_reclaim(gfp_t gfp_mask, unsigned int order,
4738 const struct alloc_context *ac)
4740 unsigned int noreclaim_flag;
4741 unsigned long progress;
4745 /* We now go into synchronous reclaim */
4746 cpuset_memory_pressure_bump();
4747 fs_reclaim_acquire(gfp_mask);
4748 noreclaim_flag = memalloc_noreclaim_save();
4750 progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
4753 memalloc_noreclaim_restore(noreclaim_flag);
4754 fs_reclaim_release(gfp_mask);
4761 /* The really slow allocator path where we enter direct reclaim */
4762 static inline struct page *
4763 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
4764 unsigned int alloc_flags, const struct alloc_context *ac,
4765 unsigned long *did_some_progress)
4767 struct page *page = NULL;
4768 unsigned long pflags;
4769 bool drained = false;
4771 psi_memstall_enter(&pflags);
4772 *did_some_progress = __perform_reclaim(gfp_mask, order, ac);
4773 if (unlikely(!(*did_some_progress)))
4777 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4780 * If an allocation failed after direct reclaim, it could be because
4781 * pages are pinned on the per-cpu lists or in high alloc reserves.
4782 * Shrink them and try again
4784 if (!page && !drained) {
4785 unreserve_highatomic_pageblock(ac, false);
4786 drain_all_pages(NULL);
4791 psi_memstall_leave(&pflags);
4796 static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
4797 const struct alloc_context *ac)
4801 pg_data_t *last_pgdat = NULL;
4802 enum zone_type highest_zoneidx = ac->highest_zoneidx;
4804 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx,
4806 if (!managed_zone(zone))
4808 if (last_pgdat != zone->zone_pgdat) {
4809 wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx);
4810 last_pgdat = zone->zone_pgdat;
4815 static inline unsigned int
4816 gfp_to_alloc_flags(gfp_t gfp_mask)
4818 unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
4821 * __GFP_HIGH is assumed to be the same as ALLOC_HIGH
4822 * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD
4823 * to save two branches.
4825 BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
4826 BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD);
4829 * The caller may dip into page reserves a bit more if the caller
4830 * cannot run direct reclaim, or if the caller has realtime scheduling
4831 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
4832 * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
4834 alloc_flags |= (__force int)
4835 (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM));
4837 if (gfp_mask & __GFP_ATOMIC) {
4839 * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
4840 * if it can't schedule.
4842 if (!(gfp_mask & __GFP_NOMEMALLOC))
4843 alloc_flags |= ALLOC_HARDER;
4845 * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
4846 * comment for __cpuset_node_allowed().
4848 alloc_flags &= ~ALLOC_CPUSET;
4849 } else if (unlikely(rt_task(current)) && in_task())
4850 alloc_flags |= ALLOC_HARDER;
4852 alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags);
4857 static bool oom_reserves_allowed(struct task_struct *tsk)
4859 if (!tsk_is_oom_victim(tsk))
4863 * !MMU doesn't have oom reaper so give access to memory reserves
4864 * only to the thread with TIF_MEMDIE set
4866 if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE))
4873 * Distinguish requests which really need access to full memory
4874 * reserves from oom victims which can live with a portion of it
4876 static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask)
4878 if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
4880 if (gfp_mask & __GFP_MEMALLOC)
4881 return ALLOC_NO_WATERMARKS;
4882 if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
4883 return ALLOC_NO_WATERMARKS;
4884 if (!in_interrupt()) {
4885 if (current->flags & PF_MEMALLOC)
4886 return ALLOC_NO_WATERMARKS;
4887 else if (oom_reserves_allowed(current))
4894 bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
4896 return !!__gfp_pfmemalloc_flags(gfp_mask);
4900 * Checks whether it makes sense to retry the reclaim to make a forward progress
4901 * for the given allocation request.
4903 * We give up when we either have tried MAX_RECLAIM_RETRIES in a row
4904 * without success, or when we couldn't even meet the watermark if we
4905 * reclaimed all remaining pages on the LRU lists.
4907 * Returns true if a retry is viable or false to enter the oom path.
4910 should_reclaim_retry(gfp_t gfp_mask, unsigned order,
4911 struct alloc_context *ac, int alloc_flags,
4912 bool did_some_progress, int *no_progress_loops)
4919 * Costly allocations might have made a progress but this doesn't mean
4920 * their order will become available due to high fragmentation so
4921 * always increment the no progress counter for them
4923 if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
4924 *no_progress_loops = 0;
4926 (*no_progress_loops)++;
4929 * Make sure we converge to OOM if we cannot make any progress
4930 * several times in the row.
4932 if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
4933 /* Before OOM, exhaust highatomic_reserve */
4934 return unreserve_highatomic_pageblock(ac, true);
4938 * Keep reclaiming pages while there is a chance this will lead
4939 * somewhere. If none of the target zones can satisfy our allocation
4940 * request even if all reclaimable pages are considered then we are
4941 * screwed and have to go OOM.
4943 for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
4944 ac->highest_zoneidx, ac->nodemask) {
4945 unsigned long available;
4946 unsigned long reclaimable;
4947 unsigned long min_wmark = min_wmark_pages(zone);
4950 available = reclaimable = zone_reclaimable_pages(zone);
4951 available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
4954 * Would the allocation succeed if we reclaimed all
4955 * reclaimable pages?
4957 wmark = __zone_watermark_ok(zone, order, min_wmark,
4958 ac->highest_zoneidx, alloc_flags, available);
4959 trace_reclaim_retry_zone(z, order, reclaimable,
4960 available, min_wmark, *no_progress_loops, wmark);
4968 * Memory allocation/reclaim might be called from a WQ context and the
4969 * current implementation of the WQ concurrency control doesn't
4970 * recognize that a particular WQ is congested if the worker thread is
4971 * looping without ever sleeping. Therefore we have to do a short sleep
4972 * here rather than calling cond_resched().
4974 if (current->flags & PF_WQ_WORKER)
4975 schedule_timeout_uninterruptible(1);
4982 check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac)
4985 * It's possible that cpuset's mems_allowed and the nodemask from
4986 * mempolicy don't intersect. This should be normally dealt with by
4987 * policy_nodemask(), but it's possible to race with cpuset update in
4988 * such a way the check therein was true, and then it became false
4989 * before we got our cpuset_mems_cookie here.
4990 * This assumes that for all allocations, ac->nodemask can come only
4991 * from MPOL_BIND mempolicy (whose documented semantics is to be ignored
4992 * when it does not intersect with the cpuset restrictions) or the
4993 * caller can deal with a violated nodemask.
4995 if (cpusets_enabled() && ac->nodemask &&
4996 !cpuset_nodemask_valid_mems_allowed(ac->nodemask)) {
4997 ac->nodemask = NULL;
5002 * When updating a task's mems_allowed or mempolicy nodemask, it is
5003 * possible to race with parallel threads in such a way that our
5004 * allocation can fail while the mask is being updated. If we are about
5005 * to fail, check if the cpuset changed during allocation and if so,
5008 if (read_mems_allowed_retry(cpuset_mems_cookie))
5014 static inline struct page *
5015 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
5016 struct alloc_context *ac)
5018 bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
5019 const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER;
5020 struct page *page = NULL;
5021 unsigned int alloc_flags;
5022 unsigned long did_some_progress;
5023 enum compact_priority compact_priority;
5024 enum compact_result compact_result;
5025 int compaction_retries;
5026 int no_progress_loops;
5027 unsigned int cpuset_mems_cookie;
5028 unsigned int zonelist_iter_cookie;
5032 * We also sanity check to catch abuse of atomic reserves being used by
5033 * callers that are not in atomic context.
5035 if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) ==
5036 (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
5037 gfp_mask &= ~__GFP_ATOMIC;
5040 compaction_retries = 0;
5041 no_progress_loops = 0;
5042 compact_priority = DEF_COMPACT_PRIORITY;
5043 cpuset_mems_cookie = read_mems_allowed_begin();
5044 zonelist_iter_cookie = zonelist_iter_begin();
5047 * The fast path uses conservative alloc_flags to succeed only until
5048 * kswapd needs to be woken up, and to avoid the cost of setting up
5049 * alloc_flags precisely. So we do that now.
5051 alloc_flags = gfp_to_alloc_flags(gfp_mask);
5054 * We need to recalculate the starting point for the zonelist iterator
5055 * because we might have used different nodemask in the fast path, or
5056 * there was a cpuset modification and we are retrying - otherwise we
5057 * could end up iterating over non-eligible zones endlessly.
5059 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
5060 ac->highest_zoneidx, ac->nodemask);
5061 if (!ac->preferred_zoneref->zone)
5065 * Check for insane configurations where the cpuset doesn't contain
5066 * any suitable zone to satisfy the request - e.g. non-movable
5067 * GFP_HIGHUSER allocations from MOVABLE nodes only.
5069 if (cpusets_insane_config() && (gfp_mask & __GFP_HARDWALL)) {
5070 struct zoneref *z = first_zones_zonelist(ac->zonelist,
5071 ac->highest_zoneidx,
5072 &cpuset_current_mems_allowed);
5077 if (alloc_flags & ALLOC_KSWAPD)
5078 wake_all_kswapds(order, gfp_mask, ac);
5081 * The adjusted alloc_flags might result in immediate success, so try
5084 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
5089 * For costly allocations, try direct compaction first, as it's likely
5090 * that we have enough base pages and don't need to reclaim. For non-
5091 * movable high-order allocations, do that as well, as compaction will
5092 * try prevent permanent fragmentation by migrating from blocks of the
5094 * Don't try this for allocations that are allowed to ignore
5095 * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen.
5097 if (can_direct_reclaim &&
5099 (order > 0 && ac->migratetype != MIGRATE_MOVABLE))
5100 && !gfp_pfmemalloc_allowed(gfp_mask)) {
5101 page = __alloc_pages_direct_compact(gfp_mask, order,
5103 INIT_COMPACT_PRIORITY,
5109 * Checks for costly allocations with __GFP_NORETRY, which
5110 * includes some THP page fault allocations
5112 if (costly_order && (gfp_mask & __GFP_NORETRY)) {
5114 * If allocating entire pageblock(s) and compaction
5115 * failed because all zones are below low watermarks
5116 * or is prohibited because it recently failed at this
5117 * order, fail immediately unless the allocator has
5118 * requested compaction and reclaim retry.
5121 * - potentially very expensive because zones are far
5122 * below their low watermarks or this is part of very
5123 * bursty high order allocations,
5124 * - not guaranteed to help because isolate_freepages()
5125 * may not iterate over freed pages as part of its
5127 * - unlikely to make entire pageblocks free on its
5130 if (compact_result == COMPACT_SKIPPED ||
5131 compact_result == COMPACT_DEFERRED)
5135 * Looks like reclaim/compaction is worth trying, but
5136 * sync compaction could be very expensive, so keep
5137 * using async compaction.
5139 compact_priority = INIT_COMPACT_PRIORITY;
5144 /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
5145 if (alloc_flags & ALLOC_KSWAPD)
5146 wake_all_kswapds(order, gfp_mask, ac);
5148 reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
5150 alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) |
5151 (alloc_flags & ALLOC_KSWAPD);
5154 * Reset the nodemask and zonelist iterators if memory policies can be
5155 * ignored. These allocations are high priority and system rather than
5158 if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) {
5159 ac->nodemask = NULL;
5160 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
5161 ac->highest_zoneidx, ac->nodemask);
5164 /* Attempt with potentially adjusted zonelist and alloc_flags */
5165 page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
5169 /* Caller is not willing to reclaim, we can't balance anything */
5170 if (!can_direct_reclaim)
5173 /* Avoid recursion of direct reclaim */
5174 if (current->flags & PF_MEMALLOC)
5177 /* Try direct reclaim and then allocating */
5178 page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
5179 &did_some_progress);
5183 /* Try direct compaction and then allocating */
5184 page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
5185 compact_priority, &compact_result);
5189 /* Do not loop if specifically requested */
5190 if (gfp_mask & __GFP_NORETRY)
5194 * Do not retry costly high order allocations unless they are
5195 * __GFP_RETRY_MAYFAIL
5197 if (costly_order && !(gfp_mask & __GFP_RETRY_MAYFAIL))
5200 if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
5201 did_some_progress > 0, &no_progress_loops))
5205 * It doesn't make any sense to retry for the compaction if the order-0
5206 * reclaim is not able to make any progress because the current
5207 * implementation of the compaction depends on the sufficient amount
5208 * of free memory (see __compaction_suitable)
5210 if (did_some_progress > 0 &&
5211 should_compact_retry(ac, order, alloc_flags,
5212 compact_result, &compact_priority,
5213 &compaction_retries))
5218 * Deal with possible cpuset update races or zonelist updates to avoid
5219 * a unnecessary OOM kill.
5221 if (check_retry_cpuset(cpuset_mems_cookie, ac) ||
5222 check_retry_zonelist(zonelist_iter_cookie))
5225 /* Reclaim has failed us, start killing things */
5226 page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
5230 /* Avoid allocations with no watermarks from looping endlessly */
5231 if (tsk_is_oom_victim(current) &&
5232 (alloc_flags & ALLOC_OOM ||
5233 (gfp_mask & __GFP_NOMEMALLOC)))
5236 /* Retry as long as the OOM killer is making progress */
5237 if (did_some_progress) {
5238 no_progress_loops = 0;
5244 * Deal with possible cpuset update races or zonelist updates to avoid
5245 * a unnecessary OOM kill.
5247 if (check_retry_cpuset(cpuset_mems_cookie, ac) ||
5248 check_retry_zonelist(zonelist_iter_cookie))
5252 * Make sure that __GFP_NOFAIL request doesn't leak out and make sure
5255 if (gfp_mask & __GFP_NOFAIL) {
5257 * All existing users of the __GFP_NOFAIL are blockable, so warn
5258 * of any new users that actually require GFP_NOWAIT
5260 if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask))
5264 * PF_MEMALLOC request from this context is rather bizarre
5265 * because we cannot reclaim anything and only can loop waiting
5266 * for somebody to do a work for us
5268 WARN_ON_ONCE_GFP(current->flags & PF_MEMALLOC, gfp_mask);
5271 * non failing costly orders are a hard requirement which we
5272 * are not prepared for much so let's warn about these users
5273 * so that we can identify them and convert them to something
5276 WARN_ON_ONCE_GFP(costly_order, gfp_mask);
5279 * Help non-failing allocations by giving them access to memory
5280 * reserves but do not use ALLOC_NO_WATERMARKS because this
5281 * could deplete whole memory reserves which would just make
5282 * the situation worse
5284 page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_HARDER, ac);
5292 warn_alloc(gfp_mask, ac->nodemask,
5293 "page allocation failure: order:%u", order);
5298 static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
5299 int preferred_nid, nodemask_t *nodemask,
5300 struct alloc_context *ac, gfp_t *alloc_gfp,
5301 unsigned int *alloc_flags)
5303 ac->highest_zoneidx = gfp_zone(gfp_mask);
5304 ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
5305 ac->nodemask = nodemask;
5306 ac->migratetype = gfp_migratetype(gfp_mask);
5308 if (cpusets_enabled()) {
5309 *alloc_gfp |= __GFP_HARDWALL;
5311 * When we are in the interrupt context, it is irrelevant
5312 * to the current task context. It means that any node ok.
5314 if (in_task() && !ac->nodemask)
5315 ac->nodemask = &cpuset_current_mems_allowed;
5317 *alloc_flags |= ALLOC_CPUSET;
5320 might_alloc(gfp_mask);
5322 if (should_fail_alloc_page(gfp_mask, order))
5325 *alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, *alloc_flags);
5327 /* Dirty zone balancing only done in the fast path */
5328 ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
5331 * The preferred zone is used for statistics but crucially it is
5332 * also used as the starting point for the zonelist iterator. It
5333 * may get reset for allocations that ignore memory policies.
5335 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
5336 ac->highest_zoneidx, ac->nodemask);
5342 * __alloc_pages_bulk - Allocate a number of order-0 pages to a list or array
5343 * @gfp: GFP flags for the allocation
5344 * @preferred_nid: The preferred NUMA node ID to allocate from
5345 * @nodemask: Set of nodes to allocate from, may be NULL
5346 * @nr_pages: The number of pages desired on the list or array
5347 * @page_list: Optional list to store the allocated pages
5348 * @page_array: Optional array to store the pages
5350 * This is a batched version of the page allocator that attempts to
5351 * allocate nr_pages quickly. Pages are added to page_list if page_list
5352 * is not NULL, otherwise it is assumed that the page_array is valid.
5354 * For lists, nr_pages is the number of pages that should be allocated.
5356 * For arrays, only NULL elements are populated with pages and nr_pages
5357 * is the maximum number of pages that will be stored in the array.
5359 * Returns the number of pages on the list or array.
5361 unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid,
5362 nodemask_t *nodemask, int nr_pages,
5363 struct list_head *page_list,
5364 struct page **page_array)
5367 unsigned long __maybe_unused UP_flags;
5370 struct per_cpu_pages *pcp;
5371 struct list_head *pcp_list;
5372 struct alloc_context ac;
5374 unsigned int alloc_flags = ALLOC_WMARK_LOW;
5375 int nr_populated = 0, nr_account = 0;
5378 * Skip populated array elements to determine if any pages need
5379 * to be allocated before disabling IRQs.
5381 while (page_array && nr_populated < nr_pages && page_array[nr_populated])
5384 /* No pages requested? */
5385 if (unlikely(nr_pages <= 0))
5388 /* Already populated array? */
5389 if (unlikely(page_array && nr_pages - nr_populated == 0))
5392 /* Bulk allocator does not support memcg accounting. */
5393 if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT))
5396 /* Use the single page allocator for one page. */
5397 if (nr_pages - nr_populated == 1)
5400 #ifdef CONFIG_PAGE_OWNER
5402 * PAGE_OWNER may recurse into the allocator to allocate space to
5403 * save the stack with pagesets.lock held. Releasing/reacquiring
5404 * removes much of the performance benefit of bulk allocation so
5405 * force the caller to allocate one page at a time as it'll have
5406 * similar performance to added complexity to the bulk allocator.
5408 if (static_branch_unlikely(&page_owner_inited))
5412 /* May set ALLOC_NOFRAGMENT, fragmentation will return 1 page. */
5413 gfp &= gfp_allowed_mask;
5415 if (!prepare_alloc_pages(gfp, 0, preferred_nid, nodemask, &ac, &alloc_gfp, &alloc_flags))
5419 /* Find an allowed local zone that meets the low watermark. */
5420 for_each_zone_zonelist_nodemask(zone, z, ac.zonelist, ac.highest_zoneidx, ac.nodemask) {
5423 if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) &&
5424 !__cpuset_zone_allowed(zone, gfp)) {
5428 if (nr_online_nodes > 1 && zone != ac.preferred_zoneref->zone &&
5429 zone_to_nid(zone) != zone_to_nid(ac.preferred_zoneref->zone)) {
5433 mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK) + nr_pages;
5434 if (zone_watermark_fast(zone, 0, mark,
5435 zonelist_zone_idx(ac.preferred_zoneref),
5436 alloc_flags, gfp)) {
5442 * If there are no allowed local zones that meets the watermarks then
5443 * try to allocate a single page and reclaim if necessary.
5445 if (unlikely(!zone))
5448 /* spin_trylock may fail due to a parallel drain or IRQ reentrancy. */
5449 pcp_trylock_prepare(UP_flags);
5450 pcp = pcp_spin_trylock(zone->per_cpu_pageset);
5454 /* Attempt the batch allocation */
5455 pcp_list = &pcp->lists[order_to_pindex(ac.migratetype, 0)];
5456 while (nr_populated < nr_pages) {
5458 /* Skip existing pages */
5459 if (page_array && page_array[nr_populated]) {
5464 page = __rmqueue_pcplist(zone, 0, ac.migratetype, alloc_flags,
5466 if (unlikely(!page)) {
5467 /* Try and allocate at least one page */
5469 pcp_spin_unlock(pcp);
5476 prep_new_page(page, 0, gfp, 0);
5478 list_add(&page->lru, page_list);
5480 page_array[nr_populated] = page;
5484 pcp_spin_unlock(pcp);
5485 pcp_trylock_finish(UP_flags);
5487 __count_zid_vm_events(PGALLOC, zone_idx(zone), nr_account);
5488 zone_statistics(ac.preferred_zoneref->zone, zone, nr_account);
5491 return nr_populated;
5494 pcp_trylock_finish(UP_flags);
5497 page = __alloc_pages(gfp, 0, preferred_nid, nodemask);
5500 list_add(&page->lru, page_list);
5502 page_array[nr_populated] = page;
5508 EXPORT_SYMBOL_GPL(__alloc_pages_bulk);
5511 * This is the 'heart' of the zoned buddy allocator.
5513 struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid,
5514 nodemask_t *nodemask)
5517 unsigned int alloc_flags = ALLOC_WMARK_LOW;
5518 gfp_t alloc_gfp; /* The gfp_t that was actually used for allocation */
5519 struct alloc_context ac = { };
5522 * There are several places where we assume that the order value is sane
5523 * so bail out early if the request is out of bound.
5525 if (WARN_ON_ONCE_GFP(order >= MAX_ORDER, gfp))
5528 gfp &= gfp_allowed_mask;
5530 * Apply scoped allocation constraints. This is mainly about GFP_NOFS
5531 * resp. GFP_NOIO which has to be inherited for all allocation requests
5532 * from a particular context which has been marked by
5533 * memalloc_no{fs,io}_{save,restore}. And PF_MEMALLOC_PIN which ensures
5534 * movable zones are not used during allocation.
5536 gfp = current_gfp_context(gfp);
5538 if (!prepare_alloc_pages(gfp, order, preferred_nid, nodemask, &ac,
5539 &alloc_gfp, &alloc_flags))
5543 * Forbid the first pass from falling back to types that fragment
5544 * memory until all local zones are considered.
5546 alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp);
5548 /* First allocation attempt */
5549 page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac);
5554 ac.spread_dirty_pages = false;
5557 * Restore the original nodemask if it was potentially replaced with
5558 * &cpuset_current_mems_allowed to optimize the fast-path attempt.
5560 ac.nodemask = nodemask;
5562 page = __alloc_pages_slowpath(alloc_gfp, order, &ac);
5565 if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT) && page &&
5566 unlikely(__memcg_kmem_charge_page(page, gfp, order) != 0)) {
5567 __free_pages(page, order);
5571 trace_mm_page_alloc(page, order, alloc_gfp, ac.migratetype);
5572 kmsan_alloc_page(page, order, alloc_gfp);
5576 EXPORT_SYMBOL(__alloc_pages);
5578 struct folio *__folio_alloc(gfp_t gfp, unsigned int order, int preferred_nid,
5579 nodemask_t *nodemask)
5581 struct page *page = __alloc_pages(gfp | __GFP_COMP, order,
5582 preferred_nid, nodemask);
5584 if (page && order > 1)
5585 prep_transhuge_page(page);
5586 return (struct folio *)page;
5588 EXPORT_SYMBOL(__folio_alloc);
5591 * Common helper functions. Never use with __GFP_HIGHMEM because the returned
5592 * address cannot represent highmem pages. Use alloc_pages and then kmap if
5593 * you need to access high mem.
5595 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
5599 page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, order);
5602 return (unsigned long) page_address(page);
5604 EXPORT_SYMBOL(__get_free_pages);
5606 unsigned long get_zeroed_page(gfp_t gfp_mask)
5608 return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
5610 EXPORT_SYMBOL(get_zeroed_page);
5613 * __free_pages - Free pages allocated with alloc_pages().
5614 * @page: The page pointer returned from alloc_pages().
5615 * @order: The order of the allocation.
5617 * This function can free multi-page allocations that are not compound
5618 * pages. It does not check that the @order passed in matches that of
5619 * the allocation, so it is easy to leak memory. Freeing more memory
5620 * than was allocated will probably emit a warning.
5622 * If the last reference to this page is speculative, it will be released
5623 * by put_page() which only frees the first page of a non-compound
5624 * allocation. To prevent the remaining pages from being leaked, we free
5625 * the subsequent pages here. If you want to use the page's reference
5626 * count to decide when to free the allocation, you should allocate a
5627 * compound page, and use put_page() instead of __free_pages().
5629 * Context: May be called in interrupt context or while holding a normal
5630 * spinlock, but not in NMI context or while holding a raw spinlock.
5632 void __free_pages(struct page *page, unsigned int order)
5634 /* get PageHead before we drop reference */
5635 int head = PageHead(page);
5637 if (put_page_testzero(page))
5638 free_the_page(page, order);
5641 free_the_page(page + (1 << order), order);
5643 EXPORT_SYMBOL(__free_pages);
5645 void free_pages(unsigned long addr, unsigned int order)
5648 VM_BUG_ON(!virt_addr_valid((void *)addr));
5649 __free_pages(virt_to_page((void *)addr), order);
5653 EXPORT_SYMBOL(free_pages);
5657 * An arbitrary-length arbitrary-offset area of memory which resides
5658 * within a 0 or higher order page. Multiple fragments within that page
5659 * are individually refcounted, in the page's reference counter.
5661 * The page_frag functions below provide a simple allocation framework for
5662 * page fragments. This is used by the network stack and network device
5663 * drivers to provide a backing region of memory for use as either an
5664 * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
5666 static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
5669 struct page *page = NULL;
5670 gfp_t gfp = gfp_mask;
5672 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
5673 gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
5675 page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
5676 PAGE_FRAG_CACHE_MAX_ORDER);
5677 nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
5679 if (unlikely(!page))
5680 page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
5682 nc->va = page ? page_address(page) : NULL;
5687 void __page_frag_cache_drain(struct page *page, unsigned int count)
5689 VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
5691 if (page_ref_sub_and_test(page, count))
5692 free_the_page(page, compound_order(page));
5694 EXPORT_SYMBOL(__page_frag_cache_drain);
5696 void *page_frag_alloc_align(struct page_frag_cache *nc,
5697 unsigned int fragsz, gfp_t gfp_mask,
5698 unsigned int align_mask)
5700 unsigned int size = PAGE_SIZE;
5704 if (unlikely(!nc->va)) {
5706 page = __page_frag_cache_refill(nc, gfp_mask);
5710 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
5711 /* if size can vary use size else just use PAGE_SIZE */
5714 /* Even if we own the page, we do not use atomic_set().
5715 * This would break get_page_unless_zero() users.
5717 page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE);
5719 /* reset page count bias and offset to start of new frag */
5720 nc->pfmemalloc = page_is_pfmemalloc(page);
5721 nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
5725 offset = nc->offset - fragsz;
5726 if (unlikely(offset < 0)) {
5727 page = virt_to_page(nc->va);
5729 if (!page_ref_sub_and_test(page, nc->pagecnt_bias))
5732 if (unlikely(nc->pfmemalloc)) {
5733 free_the_page(page, compound_order(page));
5737 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
5738 /* if size can vary use size else just use PAGE_SIZE */
5741 /* OK, page count is 0, we can safely set it */
5742 set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1);
5744 /* reset page count bias and offset to start of new frag */
5745 nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
5746 offset = size - fragsz;
5747 if (unlikely(offset < 0)) {
5749 * The caller is trying to allocate a fragment
5750 * with fragsz > PAGE_SIZE but the cache isn't big
5751 * enough to satisfy the request, this may
5752 * happen in low memory conditions.
5753 * We don't release the cache page because
5754 * it could make memory pressure worse
5755 * so we simply return NULL here.
5762 offset &= align_mask;
5763 nc->offset = offset;
5765 return nc->va + offset;
5767 EXPORT_SYMBOL(page_frag_alloc_align);
5770 * Frees a page fragment allocated out of either a compound or order 0 page.
5772 void page_frag_free(void *addr)
5774 struct page *page = virt_to_head_page(addr);
5776 if (unlikely(put_page_testzero(page)))
5777 free_the_page(page, compound_order(page));
5779 EXPORT_SYMBOL(page_frag_free);
5781 static void *make_alloc_exact(unsigned long addr, unsigned int order,
5785 unsigned long nr = DIV_ROUND_UP(size, PAGE_SIZE);
5786 struct page *page = virt_to_page((void *)addr);
5787 struct page *last = page + nr;
5789 split_page_owner(page, 1 << order);
5790 split_page_memcg(page, 1 << order);
5791 while (page < --last)
5792 set_page_refcounted(last);
5794 last = page + (1UL << order);
5795 for (page += nr; page < last; page++)
5796 __free_pages_ok(page, 0, FPI_TO_TAIL);
5798 return (void *)addr;
5802 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
5803 * @size: the number of bytes to allocate
5804 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
5806 * This function is similar to alloc_pages(), except that it allocates the
5807 * minimum number of pages to satisfy the request. alloc_pages() can only
5808 * allocate memory in power-of-two pages.
5810 * This function is also limited by MAX_ORDER.
5812 * Memory allocated by this function must be released by free_pages_exact().
5814 * Return: pointer to the allocated area or %NULL in case of error.
5816 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
5818 unsigned int order = get_order(size);
5821 if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM)))
5822 gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM);
5824 addr = __get_free_pages(gfp_mask, order);
5825 return make_alloc_exact(addr, order, size);
5827 EXPORT_SYMBOL(alloc_pages_exact);
5830 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
5832 * @nid: the preferred node ID where memory should be allocated
5833 * @size: the number of bytes to allocate
5834 * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
5836 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
5839 * Return: pointer to the allocated area or %NULL in case of error.
5841 void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
5843 unsigned int order = get_order(size);
5846 if (WARN_ON_ONCE(gfp_mask & (__GFP_COMP | __GFP_HIGHMEM)))
5847 gfp_mask &= ~(__GFP_COMP | __GFP_HIGHMEM);
5849 p = alloc_pages_node(nid, gfp_mask, order);
5852 return make_alloc_exact((unsigned long)page_address(p), order, size);
5856 * free_pages_exact - release memory allocated via alloc_pages_exact()
5857 * @virt: the value returned by alloc_pages_exact.
5858 * @size: size of allocation, same value as passed to alloc_pages_exact().
5860 * Release the memory allocated by a previous call to alloc_pages_exact.
5862 void free_pages_exact(void *virt, size_t size)
5864 unsigned long addr = (unsigned long)virt;
5865 unsigned long end = addr + PAGE_ALIGN(size);
5867 while (addr < end) {
5872 EXPORT_SYMBOL(free_pages_exact);
5875 * nr_free_zone_pages - count number of pages beyond high watermark
5876 * @offset: The zone index of the highest zone
5878 * nr_free_zone_pages() counts the number of pages which are beyond the
5879 * high watermark within all zones at or below a given zone index. For each
5880 * zone, the number of pages is calculated as:
5882 * nr_free_zone_pages = managed_pages - high_pages
5884 * Return: number of pages beyond high watermark.
5886 static unsigned long nr_free_zone_pages(int offset)
5891 /* Just pick one node, since fallback list is circular */
5892 unsigned long sum = 0;
5894 struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
5896 for_each_zone_zonelist(zone, z, zonelist, offset) {
5897 unsigned long size = zone_managed_pages(zone);
5898 unsigned long high = high_wmark_pages(zone);
5907 * nr_free_buffer_pages - count number of pages beyond high watermark
5909 * nr_free_buffer_pages() counts the number of pages which are beyond the high
5910 * watermark within ZONE_DMA and ZONE_NORMAL.
5912 * Return: number of pages beyond high watermark within ZONE_DMA and
5915 unsigned long nr_free_buffer_pages(void)
5917 return nr_free_zone_pages(gfp_zone(GFP_USER));
5919 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
5921 static inline void show_node(struct zone *zone)
5923 if (IS_ENABLED(CONFIG_NUMA))
5924 printk("Node %d ", zone_to_nid(zone));
5927 long si_mem_available(void)
5930 unsigned long pagecache;
5931 unsigned long wmark_low = 0;
5932 unsigned long pages[NR_LRU_LISTS];
5933 unsigned long reclaimable;
5937 for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
5938 pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
5941 wmark_low += low_wmark_pages(zone);
5944 * Estimate the amount of memory available for userspace allocations,
5945 * without causing swapping or OOM.
5947 available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages;
5950 * Not all the page cache can be freed, otherwise the system will
5951 * start swapping or thrashing. Assume at least half of the page
5952 * cache, or the low watermark worth of cache, needs to stay.
5954 pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
5955 pagecache -= min(pagecache / 2, wmark_low);
5956 available += pagecache;
5959 * Part of the reclaimable slab and other kernel memory consists of
5960 * items that are in use, and cannot be freed. Cap this estimate at the
5963 reclaimable = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B) +
5964 global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
5965 available += reclaimable - min(reclaimable / 2, wmark_low);
5971 EXPORT_SYMBOL_GPL(si_mem_available);
5973 void si_meminfo(struct sysinfo *val)
5975 val->totalram = totalram_pages();
5976 val->sharedram = global_node_page_state(NR_SHMEM);
5977 val->freeram = global_zone_page_state(NR_FREE_PAGES);
5978 val->bufferram = nr_blockdev_pages();
5979 val->totalhigh = totalhigh_pages();
5980 val->freehigh = nr_free_highpages();
5981 val->mem_unit = PAGE_SIZE;
5984 EXPORT_SYMBOL(si_meminfo);
5987 void si_meminfo_node(struct sysinfo *val, int nid)
5989 int zone_type; /* needs to be signed */
5990 unsigned long managed_pages = 0;
5991 unsigned long managed_highpages = 0;
5992 unsigned long free_highpages = 0;
5993 pg_data_t *pgdat = NODE_DATA(nid);
5995 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
5996 managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]);
5997 val->totalram = managed_pages;
5998 val->sharedram = node_page_state(pgdat, NR_SHMEM);
5999 val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
6000 #ifdef CONFIG_HIGHMEM
6001 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
6002 struct zone *zone = &pgdat->node_zones[zone_type];
6004 if (is_highmem(zone)) {
6005 managed_highpages += zone_managed_pages(zone);
6006 free_highpages += zone_page_state(zone, NR_FREE_PAGES);
6009 val->totalhigh = managed_highpages;
6010 val->freehigh = free_highpages;
6012 val->totalhigh = managed_highpages;
6013 val->freehigh = free_highpages;
6015 val->mem_unit = PAGE_SIZE;
6020 * Determine whether the node should be displayed or not, depending on whether
6021 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
6023 static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask)
6025 if (!(flags & SHOW_MEM_FILTER_NODES))
6029 * no node mask - aka implicit memory numa policy. Do not bother with
6030 * the synchronization - read_mems_allowed_begin - because we do not
6031 * have to be precise here.
6034 nodemask = &cpuset_current_mems_allowed;
6036 return !node_isset(nid, *nodemask);
6039 #define K(x) ((x) << (PAGE_SHIFT-10))
6041 static void show_migration_types(unsigned char type)
6043 static const char types[MIGRATE_TYPES] = {
6044 [MIGRATE_UNMOVABLE] = 'U',
6045 [MIGRATE_MOVABLE] = 'M',
6046 [MIGRATE_RECLAIMABLE] = 'E',
6047 [MIGRATE_HIGHATOMIC] = 'H',
6049 [MIGRATE_CMA] = 'C',
6051 #ifdef CONFIG_MEMORY_ISOLATION
6052 [MIGRATE_ISOLATE] = 'I',
6055 char tmp[MIGRATE_TYPES + 1];
6059 for (i = 0; i < MIGRATE_TYPES; i++) {
6060 if (type & (1 << i))
6065 printk(KERN_CONT "(%s) ", tmp);
6068 static bool node_has_managed_zones(pg_data_t *pgdat, int max_zone_idx)
6071 for (zone_idx = 0; zone_idx <= max_zone_idx; zone_idx++)
6072 if (zone_managed_pages(pgdat->node_zones + zone_idx))
6078 * Show free area list (used inside shift_scroll-lock stuff)
6079 * We also calculate the percentage fragmentation. We do this by counting the
6080 * memory on each free list with the exception of the first item on the list.
6083 * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
6086 void __show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_zone_idx)
6088 unsigned long free_pcp = 0;
6093 for_each_populated_zone(zone) {
6094 if (zone_idx(zone) > max_zone_idx)
6096 if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
6099 for_each_online_cpu(cpu)
6100 free_pcp += per_cpu_ptr(zone->per_cpu_pageset, cpu)->count;
6103 printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
6104 " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
6105 " unevictable:%lu dirty:%lu writeback:%lu\n"
6106 " slab_reclaimable:%lu slab_unreclaimable:%lu\n"
6107 " mapped:%lu shmem:%lu pagetables:%lu\n"
6108 " sec_pagetables:%lu bounce:%lu\n"
6109 " kernel_misc_reclaimable:%lu\n"
6110 " free:%lu free_pcp:%lu free_cma:%lu\n",
6111 global_node_page_state(NR_ACTIVE_ANON),
6112 global_node_page_state(NR_INACTIVE_ANON),
6113 global_node_page_state(NR_ISOLATED_ANON),
6114 global_node_page_state(NR_ACTIVE_FILE),
6115 global_node_page_state(NR_INACTIVE_FILE),
6116 global_node_page_state(NR_ISOLATED_FILE),
6117 global_node_page_state(NR_UNEVICTABLE),
6118 global_node_page_state(NR_FILE_DIRTY),
6119 global_node_page_state(NR_WRITEBACK),
6120 global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B),
6121 global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B),
6122 global_node_page_state(NR_FILE_MAPPED),
6123 global_node_page_state(NR_SHMEM),
6124 global_node_page_state(NR_PAGETABLE),
6125 global_node_page_state(NR_SECONDARY_PAGETABLE),
6126 global_zone_page_state(NR_BOUNCE),
6127 global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE),
6128 global_zone_page_state(NR_FREE_PAGES),
6130 global_zone_page_state(NR_FREE_CMA_PAGES));
6132 for_each_online_pgdat(pgdat) {
6133 if (show_mem_node_skip(filter, pgdat->node_id, nodemask))
6135 if (!node_has_managed_zones(pgdat, max_zone_idx))
6139 " active_anon:%lukB"
6140 " inactive_anon:%lukB"
6141 " active_file:%lukB"
6142 " inactive_file:%lukB"
6143 " unevictable:%lukB"
6144 " isolated(anon):%lukB"
6145 " isolated(file):%lukB"
6150 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6152 " shmem_pmdmapped: %lukB"
6155 " writeback_tmp:%lukB"
6156 " kernel_stack:%lukB"
6157 #ifdef CONFIG_SHADOW_CALL_STACK
6158 " shadow_call_stack:%lukB"
6161 " sec_pagetables:%lukB"
6162 " all_unreclaimable? %s"
6165 K(node_page_state(pgdat, NR_ACTIVE_ANON)),
6166 K(node_page_state(pgdat, NR_INACTIVE_ANON)),
6167 K(node_page_state(pgdat, NR_ACTIVE_FILE)),
6168 K(node_page_state(pgdat, NR_INACTIVE_FILE)),
6169 K(node_page_state(pgdat, NR_UNEVICTABLE)),
6170 K(node_page_state(pgdat, NR_ISOLATED_ANON)),
6171 K(node_page_state(pgdat, NR_ISOLATED_FILE)),
6172 K(node_page_state(pgdat, NR_FILE_MAPPED)),
6173 K(node_page_state(pgdat, NR_FILE_DIRTY)),
6174 K(node_page_state(pgdat, NR_WRITEBACK)),
6175 K(node_page_state(pgdat, NR_SHMEM)),
6176 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6177 K(node_page_state(pgdat, NR_SHMEM_THPS)),
6178 K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)),
6179 K(node_page_state(pgdat, NR_ANON_THPS)),
6181 K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
6182 node_page_state(pgdat, NR_KERNEL_STACK_KB),
6183 #ifdef CONFIG_SHADOW_CALL_STACK
6184 node_page_state(pgdat, NR_KERNEL_SCS_KB),
6186 K(node_page_state(pgdat, NR_PAGETABLE)),
6187 K(node_page_state(pgdat, NR_SECONDARY_PAGETABLE)),
6188 pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ?
6192 for_each_populated_zone(zone) {
6195 if (zone_idx(zone) > max_zone_idx)
6197 if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
6201 for_each_online_cpu(cpu)
6202 free_pcp += per_cpu_ptr(zone->per_cpu_pageset, cpu)->count;
6212 " reserved_highatomic:%luKB"
6213 " active_anon:%lukB"
6214 " inactive_anon:%lukB"
6215 " active_file:%lukB"
6216 " inactive_file:%lukB"
6217 " unevictable:%lukB"
6218 " writepending:%lukB"
6228 K(zone_page_state(zone, NR_FREE_PAGES)),
6229 K(zone->watermark_boost),
6230 K(min_wmark_pages(zone)),
6231 K(low_wmark_pages(zone)),
6232 K(high_wmark_pages(zone)),
6233 K(zone->nr_reserved_highatomic),
6234 K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)),
6235 K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)),
6236 K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
6237 K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
6238 K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
6239 K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
6240 K(zone->present_pages),
6241 K(zone_managed_pages(zone)),
6242 K(zone_page_state(zone, NR_MLOCK)),
6243 K(zone_page_state(zone, NR_BOUNCE)),
6245 K(this_cpu_read(zone->per_cpu_pageset->count)),
6246 K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
6247 printk("lowmem_reserve[]:");
6248 for (i = 0; i < MAX_NR_ZONES; i++)
6249 printk(KERN_CONT " %ld", zone->lowmem_reserve[i]);
6250 printk(KERN_CONT "\n");
6253 for_each_populated_zone(zone) {
6255 unsigned long nr[MAX_ORDER], flags, total = 0;
6256 unsigned char types[MAX_ORDER];
6258 if (zone_idx(zone) > max_zone_idx)
6260 if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
6263 printk(KERN_CONT "%s: ", zone->name);
6265 spin_lock_irqsave(&zone->lock, flags);
6266 for (order = 0; order < MAX_ORDER; order++) {
6267 struct free_area *area = &zone->free_area[order];
6270 nr[order] = area->nr_free;
6271 total += nr[order] << order;
6274 for (type = 0; type < MIGRATE_TYPES; type++) {
6275 if (!free_area_empty(area, type))
6276 types[order] |= 1 << type;
6279 spin_unlock_irqrestore(&zone->lock, flags);
6280 for (order = 0; order < MAX_ORDER; order++) {
6281 printk(KERN_CONT "%lu*%lukB ",
6282 nr[order], K(1UL) << order);
6284 show_migration_types(types[order]);
6286 printk(KERN_CONT "= %lukB\n", K(total));
6289 for_each_online_node(nid) {
6290 if (show_mem_node_skip(filter, nid, nodemask))
6292 hugetlb_show_meminfo_node(nid);
6295 printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
6297 show_swap_cache_info();
6300 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
6302 zoneref->zone = zone;
6303 zoneref->zone_idx = zone_idx(zone);
6307 * Builds allocation fallback zone lists.
6309 * Add all populated zones of a node to the zonelist.
6311 static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs)
6314 enum zone_type zone_type = MAX_NR_ZONES;
6319 zone = pgdat->node_zones + zone_type;
6320 if (populated_zone(zone)) {
6321 zoneref_set_zone(zone, &zonerefs[nr_zones++]);
6322 check_highest_zone(zone_type);
6324 } while (zone_type);
6331 static int __parse_numa_zonelist_order(char *s)
6334 * We used to support different zonelists modes but they turned
6335 * out to be just not useful. Let's keep the warning in place
6336 * if somebody still use the cmd line parameter so that we do
6337 * not fail it silently
6339 if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) {
6340 pr_warn("Ignoring unsupported numa_zonelist_order value: %s\n", s);
6346 char numa_zonelist_order[] = "Node";
6349 * sysctl handler for numa_zonelist_order
6351 int numa_zonelist_order_handler(struct ctl_table *table, int write,
6352 void *buffer, size_t *length, loff_t *ppos)
6355 return __parse_numa_zonelist_order(buffer);
6356 return proc_dostring(table, write, buffer, length, ppos);
6360 static int node_load[MAX_NUMNODES];
6363 * find_next_best_node - find the next node that should appear in a given node's fallback list
6364 * @node: node whose fallback list we're appending
6365 * @used_node_mask: nodemask_t of already used nodes
6367 * We use a number of factors to determine which is the next node that should
6368 * appear on a given node's fallback list. The node should not have appeared
6369 * already in @node's fallback list, and it should be the next closest node
6370 * according to the distance array (which contains arbitrary distance values
6371 * from each node to each node in the system), and should also prefer nodes
6372 * with no CPUs, since presumably they'll have very little allocation pressure
6373 * on them otherwise.
6375 * Return: node id of the found node or %NUMA_NO_NODE if no node is found.
6377 int find_next_best_node(int node, nodemask_t *used_node_mask)
6380 int min_val = INT_MAX;
6381 int best_node = NUMA_NO_NODE;
6383 /* Use the local node if we haven't already */
6384 if (!node_isset(node, *used_node_mask)) {
6385 node_set(node, *used_node_mask);
6389 for_each_node_state(n, N_MEMORY) {
6391 /* Don't want a node to appear more than once */
6392 if (node_isset(n, *used_node_mask))
6395 /* Use the distance array to find the distance */
6396 val = node_distance(node, n);
6398 /* Penalize nodes under us ("prefer the next node") */
6401 /* Give preference to headless and unused nodes */
6402 if (!cpumask_empty(cpumask_of_node(n)))
6403 val += PENALTY_FOR_NODE_WITH_CPUS;
6405 /* Slight preference for less loaded node */
6406 val *= MAX_NUMNODES;
6407 val += node_load[n];
6409 if (val < min_val) {
6416 node_set(best_node, *used_node_mask);
6423 * Build zonelists ordered by node and zones within node.
6424 * This results in maximum locality--normal zone overflows into local
6425 * DMA zone, if any--but risks exhausting DMA zone.
6427 static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order,
6430 struct zoneref *zonerefs;
6433 zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
6435 for (i = 0; i < nr_nodes; i++) {
6438 pg_data_t *node = NODE_DATA(node_order[i]);
6440 nr_zones = build_zonerefs_node(node, zonerefs);
6441 zonerefs += nr_zones;
6443 zonerefs->zone = NULL;
6444 zonerefs->zone_idx = 0;
6448 * Build gfp_thisnode zonelists
6450 static void build_thisnode_zonelists(pg_data_t *pgdat)
6452 struct zoneref *zonerefs;
6455 zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs;
6456 nr_zones = build_zonerefs_node(pgdat, zonerefs);
6457 zonerefs += nr_zones;
6458 zonerefs->zone = NULL;
6459 zonerefs->zone_idx = 0;
6463 * Build zonelists ordered by zone and nodes within zones.
6464 * This results in conserving DMA zone[s] until all Normal memory is
6465 * exhausted, but results in overflowing to remote node while memory
6466 * may still exist in local DMA zone.
6469 static void build_zonelists(pg_data_t *pgdat)
6471 static int node_order[MAX_NUMNODES];
6472 int node, nr_nodes = 0;
6473 nodemask_t used_mask = NODE_MASK_NONE;
6474 int local_node, prev_node;
6476 /* NUMA-aware ordering of nodes */
6477 local_node = pgdat->node_id;
6478 prev_node = local_node;
6480 memset(node_order, 0, sizeof(node_order));
6481 while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
6483 * We don't want to pressure a particular node.
6484 * So adding penalty to the first node in same
6485 * distance group to make it round-robin.
6487 if (node_distance(local_node, node) !=
6488 node_distance(local_node, prev_node))
6489 node_load[node] += 1;
6491 node_order[nr_nodes++] = node;
6495 build_zonelists_in_node_order(pgdat, node_order, nr_nodes);
6496 build_thisnode_zonelists(pgdat);
6497 pr_info("Fallback order for Node %d: ", local_node);
6498 for (node = 0; node < nr_nodes; node++)
6499 pr_cont("%d ", node_order[node]);
6503 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
6505 * Return node id of node used for "local" allocations.
6506 * I.e., first node id of first zone in arg node's generic zonelist.
6507 * Used for initializing percpu 'numa_mem', which is used primarily
6508 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
6510 int local_memory_node(int node)
6514 z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
6515 gfp_zone(GFP_KERNEL),
6517 return zone_to_nid(z->zone);
6521 static void setup_min_unmapped_ratio(void);
6522 static void setup_min_slab_ratio(void);
6523 #else /* CONFIG_NUMA */
6525 static void build_zonelists(pg_data_t *pgdat)
6527 int node, local_node;
6528 struct zoneref *zonerefs;
6531 local_node = pgdat->node_id;
6533 zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
6534 nr_zones = build_zonerefs_node(pgdat, zonerefs);
6535 zonerefs += nr_zones;
6538 * Now we build the zonelist so that it contains the zones
6539 * of all the other nodes.
6540 * We don't want to pressure a particular node, so when
6541 * building the zones for node N, we make sure that the
6542 * zones coming right after the local ones are those from
6543 * node N+1 (modulo N)
6545 for (node = local_node + 1; node < MAX_NUMNODES; node++) {
6546 if (!node_online(node))
6548 nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
6549 zonerefs += nr_zones;
6551 for (node = 0; node < local_node; node++) {
6552 if (!node_online(node))
6554 nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
6555 zonerefs += nr_zones;
6558 zonerefs->zone = NULL;
6559 zonerefs->zone_idx = 0;
6562 #endif /* CONFIG_NUMA */
6565 * Boot pageset table. One per cpu which is going to be used for all
6566 * zones and all nodes. The parameters will be set in such a way
6567 * that an item put on a list will immediately be handed over to
6568 * the buddy list. This is safe since pageset manipulation is done
6569 * with interrupts disabled.
6571 * The boot_pagesets must be kept even after bootup is complete for
6572 * unused processors and/or zones. They do play a role for bootstrapping
6573 * hotplugged processors.
6575 * zoneinfo_show() and maybe other functions do
6576 * not check if the processor is online before following the pageset pointer.
6577 * Other parts of the kernel may not check if the zone is available.
6579 static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats);
6580 /* These effectively disable the pcplists in the boot pageset completely */
6581 #define BOOT_PAGESET_HIGH 0
6582 #define BOOT_PAGESET_BATCH 1
6583 static DEFINE_PER_CPU(struct per_cpu_pages, boot_pageset);
6584 static DEFINE_PER_CPU(struct per_cpu_zonestat, boot_zonestats);
6585 static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
6587 static void __build_all_zonelists(void *data)
6590 int __maybe_unused cpu;
6591 pg_data_t *self = data;
6593 write_seqlock(&zonelist_update_seq);
6596 memset(node_load, 0, sizeof(node_load));
6600 * This node is hotadded and no memory is yet present. So just
6601 * building zonelists is fine - no need to touch other nodes.
6603 if (self && !node_online(self->node_id)) {
6604 build_zonelists(self);
6607 * All possible nodes have pgdat preallocated
6610 for_each_node(nid) {
6611 pg_data_t *pgdat = NODE_DATA(nid);
6613 build_zonelists(pgdat);
6616 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
6618 * We now know the "local memory node" for each node--
6619 * i.e., the node of the first zone in the generic zonelist.
6620 * Set up numa_mem percpu variable for on-line cpus. During
6621 * boot, only the boot cpu should be on-line; we'll init the
6622 * secondary cpus' numa_mem as they come on-line. During
6623 * node/memory hotplug, we'll fixup all on-line cpus.
6625 for_each_online_cpu(cpu)
6626 set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
6630 write_sequnlock(&zonelist_update_seq);
6633 static noinline void __init
6634 build_all_zonelists_init(void)
6638 __build_all_zonelists(NULL);
6641 * Initialize the boot_pagesets that are going to be used
6642 * for bootstrapping processors. The real pagesets for
6643 * each zone will be allocated later when the per cpu
6644 * allocator is available.
6646 * boot_pagesets are used also for bootstrapping offline
6647 * cpus if the system is already booted because the pagesets
6648 * are needed to initialize allocators on a specific cpu too.
6649 * F.e. the percpu allocator needs the page allocator which
6650 * needs the percpu allocator in order to allocate its pagesets
6651 * (a chicken-egg dilemma).
6653 for_each_possible_cpu(cpu)
6654 per_cpu_pages_init(&per_cpu(boot_pageset, cpu), &per_cpu(boot_zonestats, cpu));
6656 mminit_verify_zonelist();
6657 cpuset_init_current_mems_allowed();
6661 * unless system_state == SYSTEM_BOOTING.
6663 * __ref due to call of __init annotated helper build_all_zonelists_init
6664 * [protected by SYSTEM_BOOTING].
6666 void __ref build_all_zonelists(pg_data_t *pgdat)
6668 unsigned long vm_total_pages;
6670 if (system_state == SYSTEM_BOOTING) {
6671 build_all_zonelists_init();
6673 __build_all_zonelists(pgdat);
6674 /* cpuset refresh routine should be here */
6676 /* Get the number of free pages beyond high watermark in all zones. */
6677 vm_total_pages = nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
6679 * Disable grouping by mobility if the number of pages in the
6680 * system is too low to allow the mechanism to work. It would be
6681 * more accurate, but expensive to check per-zone. This check is
6682 * made on memory-hotadd so a system can start with mobility
6683 * disabled and enable it later
6685 if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
6686 page_group_by_mobility_disabled = 1;
6688 page_group_by_mobility_disabled = 0;
6690 pr_info("Built %u zonelists, mobility grouping %s. Total pages: %ld\n",
6692 page_group_by_mobility_disabled ? "off" : "on",
6695 pr_info("Policy zone: %s\n", zone_names[policy_zone]);
6699 /* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
6700 static bool __meminit
6701 overlap_memmap_init(unsigned long zone, unsigned long *pfn)
6703 static struct memblock_region *r;
6705 if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
6706 if (!r || *pfn >= memblock_region_memory_end_pfn(r)) {
6707 for_each_mem_region(r) {
6708 if (*pfn < memblock_region_memory_end_pfn(r))
6712 if (*pfn >= memblock_region_memory_base_pfn(r) &&
6713 memblock_is_mirror(r)) {
6714 *pfn = memblock_region_memory_end_pfn(r);
6722 * Initially all pages are reserved - free ones are freed
6723 * up by memblock_free_all() once the early boot process is
6724 * done. Non-atomic initialization, single-pass.
6726 * All aligned pageblocks are initialized to the specified migratetype
6727 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
6728 * zone stats (e.g., nr_isolate_pageblock) are touched.
6730 void __meminit memmap_init_range(unsigned long size, int nid, unsigned long zone,
6731 unsigned long start_pfn, unsigned long zone_end_pfn,
6732 enum meminit_context context,
6733 struct vmem_altmap *altmap, int migratetype)
6735 unsigned long pfn, end_pfn = start_pfn + size;
6738 if (highest_memmap_pfn < end_pfn - 1)
6739 highest_memmap_pfn = end_pfn - 1;
6741 #ifdef CONFIG_ZONE_DEVICE
6743 * Honor reservation requested by the driver for this ZONE_DEVICE
6744 * memory. We limit the total number of pages to initialize to just
6745 * those that might contain the memory mapping. We will defer the
6746 * ZONE_DEVICE page initialization until after we have released
6749 if (zone == ZONE_DEVICE) {
6753 if (start_pfn == altmap->base_pfn)
6754 start_pfn += altmap->reserve;
6755 end_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
6759 for (pfn = start_pfn; pfn < end_pfn; ) {
6761 * There can be holes in boot-time mem_map[]s handed to this
6762 * function. They do not exist on hotplugged memory.
6764 if (context == MEMINIT_EARLY) {
6765 if (overlap_memmap_init(zone, &pfn))
6767 if (defer_init(nid, pfn, zone_end_pfn))
6771 page = pfn_to_page(pfn);
6772 __init_single_page(page, pfn, zone, nid);
6773 if (context == MEMINIT_HOTPLUG)
6774 __SetPageReserved(page);
6777 * Usually, we want to mark the pageblock MIGRATE_MOVABLE,
6778 * such that unmovable allocations won't be scattered all
6779 * over the place during system boot.
6781 if (pageblock_aligned(pfn)) {
6782 set_pageblock_migratetype(page, migratetype);
6789 #ifdef CONFIG_ZONE_DEVICE
6790 static void __ref __init_zone_device_page(struct page *page, unsigned long pfn,
6791 unsigned long zone_idx, int nid,
6792 struct dev_pagemap *pgmap)
6795 __init_single_page(page, pfn, zone_idx, nid);
6798 * Mark page reserved as it will need to wait for onlining
6799 * phase for it to be fully associated with a zone.
6801 * We can use the non-atomic __set_bit operation for setting
6802 * the flag as we are still initializing the pages.
6804 __SetPageReserved(page);
6807 * ZONE_DEVICE pages union ->lru with a ->pgmap back pointer
6808 * and zone_device_data. It is a bug if a ZONE_DEVICE page is
6809 * ever freed or placed on a driver-private list.
6811 page->pgmap = pgmap;
6812 page->zone_device_data = NULL;
6815 * Mark the block movable so that blocks are reserved for
6816 * movable at startup. This will force kernel allocations
6817 * to reserve their blocks rather than leaking throughout
6818 * the address space during boot when many long-lived
6819 * kernel allocations are made.
6821 * Please note that MEMINIT_HOTPLUG path doesn't clear memmap
6822 * because this is done early in section_activate()
6824 if (pageblock_aligned(pfn)) {
6825 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
6830 * ZONE_DEVICE pages are released directly to the driver page allocator
6831 * which will set the page count to 1 when allocating the page.
6833 if (pgmap->type == MEMORY_DEVICE_PRIVATE ||
6834 pgmap->type == MEMORY_DEVICE_COHERENT)
6835 set_page_count(page, 0);
6839 * With compound page geometry and when struct pages are stored in ram most
6840 * tail pages are reused. Consequently, the amount of unique struct pages to
6841 * initialize is a lot smaller that the total amount of struct pages being
6842 * mapped. This is a paired / mild layering violation with explicit knowledge
6843 * of how the sparse_vmemmap internals handle compound pages in the lack
6844 * of an altmap. See vmemmap_populate_compound_pages().
6846 static inline unsigned long compound_nr_pages(struct vmem_altmap *altmap,
6847 unsigned long nr_pages)
6849 return is_power_of_2(sizeof(struct page)) &&
6850 !altmap ? 2 * (PAGE_SIZE / sizeof(struct page)) : nr_pages;
6853 static void __ref memmap_init_compound(struct page *head,
6854 unsigned long head_pfn,
6855 unsigned long zone_idx, int nid,
6856 struct dev_pagemap *pgmap,
6857 unsigned long nr_pages)
6859 unsigned long pfn, end_pfn = head_pfn + nr_pages;
6860 unsigned int order = pgmap->vmemmap_shift;
6862 __SetPageHead(head);
6863 for (pfn = head_pfn + 1; pfn < end_pfn; pfn++) {
6864 struct page *page = pfn_to_page(pfn);
6866 __init_zone_device_page(page, pfn, zone_idx, nid, pgmap);
6867 prep_compound_tail(head, pfn - head_pfn);
6868 set_page_count(page, 0);
6871 * The first tail page stores important compound page info.
6872 * Call prep_compound_head() after the first tail page has
6873 * been initialized, to not have the data overwritten.
6875 if (pfn == head_pfn + 1)
6876 prep_compound_head(head, order);
6880 void __ref memmap_init_zone_device(struct zone *zone,
6881 unsigned long start_pfn,
6882 unsigned long nr_pages,
6883 struct dev_pagemap *pgmap)
6885 unsigned long pfn, end_pfn = start_pfn + nr_pages;
6886 struct pglist_data *pgdat = zone->zone_pgdat;
6887 struct vmem_altmap *altmap = pgmap_altmap(pgmap);
6888 unsigned int pfns_per_compound = pgmap_vmemmap_nr(pgmap);
6889 unsigned long zone_idx = zone_idx(zone);
6890 unsigned long start = jiffies;
6891 int nid = pgdat->node_id;
6893 if (WARN_ON_ONCE(!pgmap || zone_idx != ZONE_DEVICE))
6897 * The call to memmap_init should have already taken care
6898 * of the pages reserved for the memmap, so we can just jump to
6899 * the end of that region and start processing the device pages.
6902 start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
6903 nr_pages = end_pfn - start_pfn;
6906 for (pfn = start_pfn; pfn < end_pfn; pfn += pfns_per_compound) {
6907 struct page *page = pfn_to_page(pfn);
6909 __init_zone_device_page(page, pfn, zone_idx, nid, pgmap);
6911 if (pfns_per_compound == 1)
6914 memmap_init_compound(page, pfn, zone_idx, nid, pgmap,
6915 compound_nr_pages(altmap, pfns_per_compound));
6918 pr_info("%s initialised %lu pages in %ums\n", __func__,
6919 nr_pages, jiffies_to_msecs(jiffies - start));
6923 static void __meminit zone_init_free_lists(struct zone *zone)
6925 unsigned int order, t;
6926 for_each_migratetype_order(order, t) {
6927 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
6928 zone->free_area[order].nr_free = 0;
6933 * Only struct pages that correspond to ranges defined by memblock.memory
6934 * are zeroed and initialized by going through __init_single_page() during
6935 * memmap_init_zone_range().
6937 * But, there could be struct pages that correspond to holes in
6938 * memblock.memory. This can happen because of the following reasons:
6939 * - physical memory bank size is not necessarily the exact multiple of the
6940 * arbitrary section size
6941 * - early reserved memory may not be listed in memblock.memory
6942 * - memory layouts defined with memmap= kernel parameter may not align
6943 * nicely with memmap sections
6945 * Explicitly initialize those struct pages so that:
6946 * - PG_Reserved is set
6947 * - zone and node links point to zone and node that span the page if the
6948 * hole is in the middle of a zone
6949 * - zone and node links point to adjacent zone/node if the hole falls on
6950 * the zone boundary; the pages in such holes will be prepended to the
6951 * zone/node above the hole except for the trailing pages in the last
6952 * section that will be appended to the zone/node below.
6954 static void __init init_unavailable_range(unsigned long spfn,
6961 for (pfn = spfn; pfn < epfn; pfn++) {
6962 if (!pfn_valid(pageblock_start_pfn(pfn))) {
6963 pfn = pageblock_end_pfn(pfn) - 1;
6966 __init_single_page(pfn_to_page(pfn), pfn, zone, node);
6967 __SetPageReserved(pfn_to_page(pfn));
6972 pr_info("On node %d, zone %s: %lld pages in unavailable ranges",
6973 node, zone_names[zone], pgcnt);
6976 static void __init memmap_init_zone_range(struct zone *zone,
6977 unsigned long start_pfn,
6978 unsigned long end_pfn,
6979 unsigned long *hole_pfn)
6981 unsigned long zone_start_pfn = zone->zone_start_pfn;
6982 unsigned long zone_end_pfn = zone_start_pfn + zone->spanned_pages;
6983 int nid = zone_to_nid(zone), zone_id = zone_idx(zone);
6985 start_pfn = clamp(start_pfn, zone_start_pfn, zone_end_pfn);
6986 end_pfn = clamp(end_pfn, zone_start_pfn, zone_end_pfn);
6988 if (start_pfn >= end_pfn)
6991 memmap_init_range(end_pfn - start_pfn, nid, zone_id, start_pfn,
6992 zone_end_pfn, MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
6994 if (*hole_pfn < start_pfn)
6995 init_unavailable_range(*hole_pfn, start_pfn, zone_id, nid);
6997 *hole_pfn = end_pfn;
7000 static void __init memmap_init(void)
7002 unsigned long start_pfn, end_pfn;
7003 unsigned long hole_pfn = 0;
7004 int i, j, zone_id = 0, nid;
7006 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
7007 struct pglist_data *node = NODE_DATA(nid);
7009 for (j = 0; j < MAX_NR_ZONES; j++) {
7010 struct zone *zone = node->node_zones + j;
7012 if (!populated_zone(zone))
7015 memmap_init_zone_range(zone, start_pfn, end_pfn,
7021 #ifdef CONFIG_SPARSEMEM
7023 * Initialize the memory map for hole in the range [memory_end,
7025 * Append the pages in this hole to the highest zone in the last
7027 * The call to init_unavailable_range() is outside the ifdef to
7028 * silence the compiler warining about zone_id set but not used;
7029 * for FLATMEM it is a nop anyway
7031 end_pfn = round_up(end_pfn, PAGES_PER_SECTION);
7032 if (hole_pfn < end_pfn)
7034 init_unavailable_range(hole_pfn, end_pfn, zone_id, nid);
7037 void __init *memmap_alloc(phys_addr_t size, phys_addr_t align,
7038 phys_addr_t min_addr, int nid, bool exact_nid)
7043 ptr = memblock_alloc_exact_nid_raw(size, align, min_addr,
7044 MEMBLOCK_ALLOC_ACCESSIBLE,
7047 ptr = memblock_alloc_try_nid_raw(size, align, min_addr,
7048 MEMBLOCK_ALLOC_ACCESSIBLE,
7051 if (ptr && size > 0)
7052 page_init_poison(ptr, size);
7057 static int zone_batchsize(struct zone *zone)
7063 * The number of pages to batch allocate is either ~0.1%
7064 * of the zone or 1MB, whichever is smaller. The batch
7065 * size is striking a balance between allocation latency
7066 * and zone lock contention.
7068 batch = min(zone_managed_pages(zone) >> 10, SZ_1M / PAGE_SIZE);
7069 batch /= 4; /* We effectively *= 4 below */
7074 * Clamp the batch to a 2^n - 1 value. Having a power
7075 * of 2 value was found to be more likely to have
7076 * suboptimal cache aliasing properties in some cases.
7078 * For example if 2 tasks are alternately allocating
7079 * batches of pages, one task can end up with a lot
7080 * of pages of one half of the possible page colors
7081 * and the other with pages of the other colors.
7083 batch = rounddown_pow_of_two(batch + batch/2) - 1;
7088 /* The deferral and batching of frees should be suppressed under NOMMU
7091 * The problem is that NOMMU needs to be able to allocate large chunks
7092 * of contiguous memory as there's no hardware page translation to
7093 * assemble apparent contiguous memory from discontiguous pages.
7095 * Queueing large contiguous runs of pages for batching, however,
7096 * causes the pages to actually be freed in smaller chunks. As there
7097 * can be a significant delay between the individual batches being
7098 * recycled, this leads to the once large chunks of space being
7099 * fragmented and becoming unavailable for high-order allocations.
7105 static int zone_highsize(struct zone *zone, int batch, int cpu_online)
7110 unsigned long total_pages;
7112 if (!percpu_pagelist_high_fraction) {
7114 * By default, the high value of the pcp is based on the zone
7115 * low watermark so that if they are full then background
7116 * reclaim will not be started prematurely.
7118 total_pages = low_wmark_pages(zone);
7121 * If percpu_pagelist_high_fraction is configured, the high
7122 * value is based on a fraction of the managed pages in the
7125 total_pages = zone_managed_pages(zone) / percpu_pagelist_high_fraction;
7129 * Split the high value across all online CPUs local to the zone. Note
7130 * that early in boot that CPUs may not be online yet and that during
7131 * CPU hotplug that the cpumask is not yet updated when a CPU is being
7132 * onlined. For memory nodes that have no CPUs, split pcp->high across
7133 * all online CPUs to mitigate the risk that reclaim is triggered
7134 * prematurely due to pages stored on pcp lists.
7136 nr_split_cpus = cpumask_weight(cpumask_of_node(zone_to_nid(zone))) + cpu_online;
7138 nr_split_cpus = num_online_cpus();
7139 high = total_pages / nr_split_cpus;
7142 * Ensure high is at least batch*4. The multiple is based on the
7143 * historical relationship between high and batch.
7145 high = max(high, batch << 2);
7154 * pcp->high and pcp->batch values are related and generally batch is lower
7155 * than high. They are also related to pcp->count such that count is lower
7156 * than high, and as soon as it reaches high, the pcplist is flushed.
7158 * However, guaranteeing these relations at all times would require e.g. write
7159 * barriers here but also careful usage of read barriers at the read side, and
7160 * thus be prone to error and bad for performance. Thus the update only prevents
7161 * store tearing. Any new users of pcp->batch and pcp->high should ensure they
7162 * can cope with those fields changing asynchronously, and fully trust only the
7163 * pcp->count field on the local CPU with interrupts disabled.
7165 * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
7166 * outside of boot time (or some other assurance that no concurrent updaters
7169 static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
7170 unsigned long batch)
7172 WRITE_ONCE(pcp->batch, batch);
7173 WRITE_ONCE(pcp->high, high);
7176 static void per_cpu_pages_init(struct per_cpu_pages *pcp, struct per_cpu_zonestat *pzstats)
7180 memset(pcp, 0, sizeof(*pcp));
7181 memset(pzstats, 0, sizeof(*pzstats));
7183 spin_lock_init(&pcp->lock);
7184 for (pindex = 0; pindex < NR_PCP_LISTS; pindex++)
7185 INIT_LIST_HEAD(&pcp->lists[pindex]);
7188 * Set batch and high values safe for a boot pageset. A true percpu
7189 * pageset's initialization will update them subsequently. Here we don't
7190 * need to be as careful as pageset_update() as nobody can access the
7193 pcp->high = BOOT_PAGESET_HIGH;
7194 pcp->batch = BOOT_PAGESET_BATCH;
7195 pcp->free_factor = 0;
7198 static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high,
7199 unsigned long batch)
7201 struct per_cpu_pages *pcp;
7204 for_each_possible_cpu(cpu) {
7205 pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
7206 pageset_update(pcp, high, batch);
7211 * Calculate and set new high and batch values for all per-cpu pagesets of a
7212 * zone based on the zone's size.
7214 static void zone_set_pageset_high_and_batch(struct zone *zone, int cpu_online)
7216 int new_high, new_batch;
7218 new_batch = max(1, zone_batchsize(zone));
7219 new_high = zone_highsize(zone, new_batch, cpu_online);
7221 if (zone->pageset_high == new_high &&
7222 zone->pageset_batch == new_batch)
7225 zone->pageset_high = new_high;
7226 zone->pageset_batch = new_batch;
7228 __zone_set_pageset_high_and_batch(zone, new_high, new_batch);
7231 void __meminit setup_zone_pageset(struct zone *zone)
7235 /* Size may be 0 on !SMP && !NUMA */
7236 if (sizeof(struct per_cpu_zonestat) > 0)
7237 zone->per_cpu_zonestats = alloc_percpu(struct per_cpu_zonestat);
7239 zone->per_cpu_pageset = alloc_percpu(struct per_cpu_pages);
7240 for_each_possible_cpu(cpu) {
7241 struct per_cpu_pages *pcp;
7242 struct per_cpu_zonestat *pzstats;
7244 pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
7245 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
7246 per_cpu_pages_init(pcp, pzstats);
7249 zone_set_pageset_high_and_batch(zone, 0);
7253 * The zone indicated has a new number of managed_pages; batch sizes and percpu
7254 * page high values need to be recalculated.
7256 static void zone_pcp_update(struct zone *zone, int cpu_online)
7258 mutex_lock(&pcp_batch_high_lock);
7259 zone_set_pageset_high_and_batch(zone, cpu_online);
7260 mutex_unlock(&pcp_batch_high_lock);
7264 * Allocate per cpu pagesets and initialize them.
7265 * Before this call only boot pagesets were available.
7267 void __init setup_per_cpu_pageset(void)
7269 struct pglist_data *pgdat;
7271 int __maybe_unused cpu;
7273 for_each_populated_zone(zone)
7274 setup_zone_pageset(zone);
7278 * Unpopulated zones continue using the boot pagesets.
7279 * The numa stats for these pagesets need to be reset.
7280 * Otherwise, they will end up skewing the stats of
7281 * the nodes these zones are associated with.
7283 for_each_possible_cpu(cpu) {
7284 struct per_cpu_zonestat *pzstats = &per_cpu(boot_zonestats, cpu);
7285 memset(pzstats->vm_numa_event, 0,
7286 sizeof(pzstats->vm_numa_event));
7290 for_each_online_pgdat(pgdat)
7291 pgdat->per_cpu_nodestats =
7292 alloc_percpu(struct per_cpu_nodestat);
7295 static __meminit void zone_pcp_init(struct zone *zone)
7298 * per cpu subsystem is not up at this point. The following code
7299 * relies on the ability of the linker to provide the
7300 * offset of a (static) per cpu variable into the per cpu area.
7302 zone->per_cpu_pageset = &boot_pageset;
7303 zone->per_cpu_zonestats = &boot_zonestats;
7304 zone->pageset_high = BOOT_PAGESET_HIGH;
7305 zone->pageset_batch = BOOT_PAGESET_BATCH;
7307 if (populated_zone(zone))
7308 pr_debug(" %s zone: %lu pages, LIFO batch:%u\n", zone->name,
7309 zone->present_pages, zone_batchsize(zone));
7312 void __meminit init_currently_empty_zone(struct zone *zone,
7313 unsigned long zone_start_pfn,
7316 struct pglist_data *pgdat = zone->zone_pgdat;
7317 int zone_idx = zone_idx(zone) + 1;
7319 if (zone_idx > pgdat->nr_zones)
7320 pgdat->nr_zones = zone_idx;
7322 zone->zone_start_pfn = zone_start_pfn;
7324 mminit_dprintk(MMINIT_TRACE, "memmap_init",
7325 "Initialising map node %d zone %lu pfns %lu -> %lu\n",
7327 (unsigned long)zone_idx(zone),
7328 zone_start_pfn, (zone_start_pfn + size));
7330 zone_init_free_lists(zone);
7331 zone->initialized = 1;
7335 * get_pfn_range_for_nid - Return the start and end page frames for a node
7336 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
7337 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
7338 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
7340 * It returns the start and end page frame of a node based on information
7341 * provided by memblock_set_node(). If called for a node
7342 * with no available memory, a warning is printed and the start and end
7345 void __init get_pfn_range_for_nid(unsigned int nid,
7346 unsigned long *start_pfn, unsigned long *end_pfn)
7348 unsigned long this_start_pfn, this_end_pfn;
7354 for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
7355 *start_pfn = min(*start_pfn, this_start_pfn);
7356 *end_pfn = max(*end_pfn, this_end_pfn);
7359 if (*start_pfn == -1UL)
7364 * This finds a zone that can be used for ZONE_MOVABLE pages. The
7365 * assumption is made that zones within a node are ordered in monotonic
7366 * increasing memory addresses so that the "highest" populated zone is used
7368 static void __init find_usable_zone_for_movable(void)
7371 for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
7372 if (zone_index == ZONE_MOVABLE)
7375 if (arch_zone_highest_possible_pfn[zone_index] >
7376 arch_zone_lowest_possible_pfn[zone_index])
7380 VM_BUG_ON(zone_index == -1);
7381 movable_zone = zone_index;
7385 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
7386 * because it is sized independent of architecture. Unlike the other zones,
7387 * the starting point for ZONE_MOVABLE is not fixed. It may be different
7388 * in each node depending on the size of each node and how evenly kernelcore
7389 * is distributed. This helper function adjusts the zone ranges
7390 * provided by the architecture for a given node by using the end of the
7391 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
7392 * zones within a node are in order of monotonic increases memory addresses
7394 static void __init adjust_zone_range_for_zone_movable(int nid,
7395 unsigned long zone_type,
7396 unsigned long node_start_pfn,
7397 unsigned long node_end_pfn,
7398 unsigned long *zone_start_pfn,
7399 unsigned long *zone_end_pfn)
7401 /* Only adjust if ZONE_MOVABLE is on this node */
7402 if (zone_movable_pfn[nid]) {
7403 /* Size ZONE_MOVABLE */
7404 if (zone_type == ZONE_MOVABLE) {
7405 *zone_start_pfn = zone_movable_pfn[nid];
7406 *zone_end_pfn = min(node_end_pfn,
7407 arch_zone_highest_possible_pfn[movable_zone]);
7409 /* Adjust for ZONE_MOVABLE starting within this range */
7410 } else if (!mirrored_kernelcore &&
7411 *zone_start_pfn < zone_movable_pfn[nid] &&
7412 *zone_end_pfn > zone_movable_pfn[nid]) {
7413 *zone_end_pfn = zone_movable_pfn[nid];
7415 /* Check if this whole range is within ZONE_MOVABLE */
7416 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
7417 *zone_start_pfn = *zone_end_pfn;
7422 * Return the number of pages a zone spans in a node, including holes
7423 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
7425 static unsigned long __init zone_spanned_pages_in_node(int nid,
7426 unsigned long zone_type,
7427 unsigned long node_start_pfn,
7428 unsigned long node_end_pfn,
7429 unsigned long *zone_start_pfn,
7430 unsigned long *zone_end_pfn)
7432 unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
7433 unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
7434 /* When hotadd a new node from cpu_up(), the node should be empty */
7435 if (!node_start_pfn && !node_end_pfn)
7438 /* Get the start and end of the zone */
7439 *zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
7440 *zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
7441 adjust_zone_range_for_zone_movable(nid, zone_type,
7442 node_start_pfn, node_end_pfn,
7443 zone_start_pfn, zone_end_pfn);
7445 /* Check that this node has pages within the zone's required range */
7446 if (*zone_end_pfn < node_start_pfn || *zone_start_pfn > node_end_pfn)
7449 /* Move the zone boundaries inside the node if necessary */
7450 *zone_end_pfn = min(*zone_end_pfn, node_end_pfn);
7451 *zone_start_pfn = max(*zone_start_pfn, node_start_pfn);
7453 /* Return the spanned pages */
7454 return *zone_end_pfn - *zone_start_pfn;
7458 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
7459 * then all holes in the requested range will be accounted for.
7461 unsigned long __init __absent_pages_in_range(int nid,
7462 unsigned long range_start_pfn,
7463 unsigned long range_end_pfn)
7465 unsigned long nr_absent = range_end_pfn - range_start_pfn;
7466 unsigned long start_pfn, end_pfn;
7469 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
7470 start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
7471 end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
7472 nr_absent -= end_pfn - start_pfn;
7478 * absent_pages_in_range - Return number of page frames in holes within a range
7479 * @start_pfn: The start PFN to start searching for holes
7480 * @end_pfn: The end PFN to stop searching for holes
7482 * Return: the number of pages frames in memory holes within a range.
7484 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
7485 unsigned long end_pfn)
7487 return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
7490 /* Return the number of page frames in holes in a zone on a node */
7491 static unsigned long __init zone_absent_pages_in_node(int nid,
7492 unsigned long zone_type,
7493 unsigned long node_start_pfn,
7494 unsigned long node_end_pfn)
7496 unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
7497 unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
7498 unsigned long zone_start_pfn, zone_end_pfn;
7499 unsigned long nr_absent;
7501 /* When hotadd a new node from cpu_up(), the node should be empty */
7502 if (!node_start_pfn && !node_end_pfn)
7505 zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
7506 zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
7508 adjust_zone_range_for_zone_movable(nid, zone_type,
7509 node_start_pfn, node_end_pfn,
7510 &zone_start_pfn, &zone_end_pfn);
7511 nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
7514 * ZONE_MOVABLE handling.
7515 * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
7518 if (mirrored_kernelcore && zone_movable_pfn[nid]) {
7519 unsigned long start_pfn, end_pfn;
7520 struct memblock_region *r;
7522 for_each_mem_region(r) {
7523 start_pfn = clamp(memblock_region_memory_base_pfn(r),
7524 zone_start_pfn, zone_end_pfn);
7525 end_pfn = clamp(memblock_region_memory_end_pfn(r),
7526 zone_start_pfn, zone_end_pfn);
7528 if (zone_type == ZONE_MOVABLE &&
7529 memblock_is_mirror(r))
7530 nr_absent += end_pfn - start_pfn;
7532 if (zone_type == ZONE_NORMAL &&
7533 !memblock_is_mirror(r))
7534 nr_absent += end_pfn - start_pfn;
7541 static void __init calculate_node_totalpages(struct pglist_data *pgdat,
7542 unsigned long node_start_pfn,
7543 unsigned long node_end_pfn)
7545 unsigned long realtotalpages = 0, totalpages = 0;
7548 for (i = 0; i < MAX_NR_ZONES; i++) {
7549 struct zone *zone = pgdat->node_zones + i;
7550 unsigned long zone_start_pfn, zone_end_pfn;
7551 unsigned long spanned, absent;
7552 unsigned long size, real_size;
7554 spanned = zone_spanned_pages_in_node(pgdat->node_id, i,
7559 absent = zone_absent_pages_in_node(pgdat->node_id, i,
7564 real_size = size - absent;
7567 zone->zone_start_pfn = zone_start_pfn;
7569 zone->zone_start_pfn = 0;
7570 zone->spanned_pages = size;
7571 zone->present_pages = real_size;
7572 #if defined(CONFIG_MEMORY_HOTPLUG)
7573 zone->present_early_pages = real_size;
7577 realtotalpages += real_size;
7580 pgdat->node_spanned_pages = totalpages;
7581 pgdat->node_present_pages = realtotalpages;
7582 pr_debug("On node %d totalpages: %lu\n", pgdat->node_id, realtotalpages);
7585 #ifndef CONFIG_SPARSEMEM
7587 * Calculate the size of the zone->blockflags rounded to an unsigned long
7588 * Start by making sure zonesize is a multiple of pageblock_order by rounding
7589 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
7590 * round what is now in bits to nearest long in bits, then return it in
7593 static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
7595 unsigned long usemapsize;
7597 zonesize += zone_start_pfn & (pageblock_nr_pages-1);
7598 usemapsize = roundup(zonesize, pageblock_nr_pages);
7599 usemapsize = usemapsize >> pageblock_order;
7600 usemapsize *= NR_PAGEBLOCK_BITS;
7601 usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
7603 return usemapsize / 8;
7606 static void __ref setup_usemap(struct zone *zone)
7608 unsigned long usemapsize = usemap_size(zone->zone_start_pfn,
7609 zone->spanned_pages);
7610 zone->pageblock_flags = NULL;
7612 zone->pageblock_flags =
7613 memblock_alloc_node(usemapsize, SMP_CACHE_BYTES,
7615 if (!zone->pageblock_flags)
7616 panic("Failed to allocate %ld bytes for zone %s pageblock flags on node %d\n",
7617 usemapsize, zone->name, zone_to_nid(zone));
7621 static inline void setup_usemap(struct zone *zone) {}
7622 #endif /* CONFIG_SPARSEMEM */
7624 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
7626 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
7627 void __init set_pageblock_order(void)
7629 unsigned int order = MAX_ORDER - 1;
7631 /* Check that pageblock_nr_pages has not already been setup */
7632 if (pageblock_order)
7635 /* Don't let pageblocks exceed the maximum allocation granularity. */
7636 if (HPAGE_SHIFT > PAGE_SHIFT && HUGETLB_PAGE_ORDER < order)
7637 order = HUGETLB_PAGE_ORDER;
7640 * Assume the largest contiguous order of interest is a huge page.
7641 * This value may be variable depending on boot parameters on IA64 and
7644 pageblock_order = order;
7646 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
7649 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
7650 * is unused as pageblock_order is set at compile-time. See
7651 * include/linux/pageblock-flags.h for the values of pageblock_order based on
7654 void __init set_pageblock_order(void)
7658 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
7660 static unsigned long __init calc_memmap_size(unsigned long spanned_pages,
7661 unsigned long present_pages)
7663 unsigned long pages = spanned_pages;
7666 * Provide a more accurate estimation if there are holes within
7667 * the zone and SPARSEMEM is in use. If there are holes within the
7668 * zone, each populated memory region may cost us one or two extra
7669 * memmap pages due to alignment because memmap pages for each
7670 * populated regions may not be naturally aligned on page boundary.
7671 * So the (present_pages >> 4) heuristic is a tradeoff for that.
7673 if (spanned_pages > present_pages + (present_pages >> 4) &&
7674 IS_ENABLED(CONFIG_SPARSEMEM))
7675 pages = present_pages;
7677 return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
7680 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
7681 static void pgdat_init_split_queue(struct pglist_data *pgdat)
7683 struct deferred_split *ds_queue = &pgdat->deferred_split_queue;
7685 spin_lock_init(&ds_queue->split_queue_lock);
7686 INIT_LIST_HEAD(&ds_queue->split_queue);
7687 ds_queue->split_queue_len = 0;
7690 static void pgdat_init_split_queue(struct pglist_data *pgdat) {}
7693 #ifdef CONFIG_COMPACTION
7694 static void pgdat_init_kcompactd(struct pglist_data *pgdat)
7696 init_waitqueue_head(&pgdat->kcompactd_wait);
7699 static void pgdat_init_kcompactd(struct pglist_data *pgdat) {}
7702 static void __meminit pgdat_init_internals(struct pglist_data *pgdat)
7706 pgdat_resize_init(pgdat);
7707 pgdat_kswapd_lock_init(pgdat);
7709 pgdat_init_split_queue(pgdat);
7710 pgdat_init_kcompactd(pgdat);
7712 init_waitqueue_head(&pgdat->kswapd_wait);
7713 init_waitqueue_head(&pgdat->pfmemalloc_wait);
7715 for (i = 0; i < NR_VMSCAN_THROTTLE; i++)
7716 init_waitqueue_head(&pgdat->reclaim_wait[i]);
7718 pgdat_page_ext_init(pgdat);
7719 lruvec_init(&pgdat->__lruvec);
7722 static void __meminit zone_init_internals(struct zone *zone, enum zone_type idx, int nid,
7723 unsigned long remaining_pages)
7725 atomic_long_set(&zone->managed_pages, remaining_pages);
7726 zone_set_nid(zone, nid);
7727 zone->name = zone_names[idx];
7728 zone->zone_pgdat = NODE_DATA(nid);
7729 spin_lock_init(&zone->lock);
7730 zone_seqlock_init(zone);
7731 zone_pcp_init(zone);
7735 * Set up the zone data structures
7736 * - init pgdat internals
7737 * - init all zones belonging to this node
7739 * NOTE: this function is only called during memory hotplug
7741 #ifdef CONFIG_MEMORY_HOTPLUG
7742 void __ref free_area_init_core_hotplug(struct pglist_data *pgdat)
7744 int nid = pgdat->node_id;
7748 pgdat_init_internals(pgdat);
7750 if (pgdat->per_cpu_nodestats == &boot_nodestats)
7751 pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);
7754 * Reset the nr_zones, order and highest_zoneidx before reuse.
7755 * Note that kswapd will init kswapd_highest_zoneidx properly
7756 * when it starts in the near future.
7758 pgdat->nr_zones = 0;
7759 pgdat->kswapd_order = 0;
7760 pgdat->kswapd_highest_zoneidx = 0;
7761 pgdat->node_start_pfn = 0;
7762 for_each_online_cpu(cpu) {
7763 struct per_cpu_nodestat *p;
7765 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
7766 memset(p, 0, sizeof(*p));
7769 for (z = 0; z < MAX_NR_ZONES; z++)
7770 zone_init_internals(&pgdat->node_zones[z], z, nid, 0);
7775 * Set up the zone data structures:
7776 * - mark all pages reserved
7777 * - mark all memory queues empty
7778 * - clear the memory bitmaps
7780 * NOTE: pgdat should get zeroed by caller.
7781 * NOTE: this function is only called during early init.
7783 static void __init free_area_init_core(struct pglist_data *pgdat)
7786 int nid = pgdat->node_id;
7788 pgdat_init_internals(pgdat);
7789 pgdat->per_cpu_nodestats = &boot_nodestats;
7791 for (j = 0; j < MAX_NR_ZONES; j++) {
7792 struct zone *zone = pgdat->node_zones + j;
7793 unsigned long size, freesize, memmap_pages;
7795 size = zone->spanned_pages;
7796 freesize = zone->present_pages;
7799 * Adjust freesize so that it accounts for how much memory
7800 * is used by this zone for memmap. This affects the watermark
7801 * and per-cpu initialisations
7803 memmap_pages = calc_memmap_size(size, freesize);
7804 if (!is_highmem_idx(j)) {
7805 if (freesize >= memmap_pages) {
7806 freesize -= memmap_pages;
7808 pr_debug(" %s zone: %lu pages used for memmap\n",
7809 zone_names[j], memmap_pages);
7811 pr_warn(" %s zone: %lu memmap pages exceeds freesize %lu\n",
7812 zone_names[j], memmap_pages, freesize);
7815 /* Account for reserved pages */
7816 if (j == 0 && freesize > dma_reserve) {
7817 freesize -= dma_reserve;
7818 pr_debug(" %s zone: %lu pages reserved\n", zone_names[0], dma_reserve);
7821 if (!is_highmem_idx(j))
7822 nr_kernel_pages += freesize;
7823 /* Charge for highmem memmap if there are enough kernel pages */
7824 else if (nr_kernel_pages > memmap_pages * 2)
7825 nr_kernel_pages -= memmap_pages;
7826 nr_all_pages += freesize;
7829 * Set an approximate value for lowmem here, it will be adjusted
7830 * when the bootmem allocator frees pages into the buddy system.
7831 * And all highmem pages will be managed by the buddy system.
7833 zone_init_internals(zone, j, nid, freesize);
7838 set_pageblock_order();
7840 init_currently_empty_zone(zone, zone->zone_start_pfn, size);
7844 #ifdef CONFIG_FLATMEM
7845 static void __init alloc_node_mem_map(struct pglist_data *pgdat)
7847 unsigned long __maybe_unused start = 0;
7848 unsigned long __maybe_unused offset = 0;
7850 /* Skip empty nodes */
7851 if (!pgdat->node_spanned_pages)
7854 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
7855 offset = pgdat->node_start_pfn - start;
7856 /* ia64 gets its own node_mem_map, before this, without bootmem */
7857 if (!pgdat->node_mem_map) {
7858 unsigned long size, end;
7862 * The zone's endpoints aren't required to be MAX_ORDER
7863 * aligned but the node_mem_map endpoints must be in order
7864 * for the buddy allocator to function correctly.
7866 end = pgdat_end_pfn(pgdat);
7867 end = ALIGN(end, MAX_ORDER_NR_PAGES);
7868 size = (end - start) * sizeof(struct page);
7869 map = memmap_alloc(size, SMP_CACHE_BYTES, MEMBLOCK_LOW_LIMIT,
7870 pgdat->node_id, false);
7872 panic("Failed to allocate %ld bytes for node %d memory map\n",
7873 size, pgdat->node_id);
7874 pgdat->node_mem_map = map + offset;
7876 pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
7877 __func__, pgdat->node_id, (unsigned long)pgdat,
7878 (unsigned long)pgdat->node_mem_map);
7881 * With no DISCONTIG, the global mem_map is just set as node 0's
7883 if (pgdat == NODE_DATA(0)) {
7884 mem_map = NODE_DATA(0)->node_mem_map;
7885 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
7891 static inline void alloc_node_mem_map(struct pglist_data *pgdat) { }
7892 #endif /* CONFIG_FLATMEM */
7894 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
7895 static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
7897 pgdat->first_deferred_pfn = ULONG_MAX;
7900 static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
7903 static void __init free_area_init_node(int nid)
7905 pg_data_t *pgdat = NODE_DATA(nid);
7906 unsigned long start_pfn = 0;
7907 unsigned long end_pfn = 0;
7909 /* pg_data_t should be reset to zero when it's allocated */
7910 WARN_ON(pgdat->nr_zones || pgdat->kswapd_highest_zoneidx);
7912 get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
7914 pgdat->node_id = nid;
7915 pgdat->node_start_pfn = start_pfn;
7916 pgdat->per_cpu_nodestats = NULL;
7918 if (start_pfn != end_pfn) {
7919 pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
7920 (u64)start_pfn << PAGE_SHIFT,
7921 end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
7923 pr_info("Initmem setup node %d as memoryless\n", nid);
7926 calculate_node_totalpages(pgdat, start_pfn, end_pfn);
7928 alloc_node_mem_map(pgdat);
7929 pgdat_set_deferred_range(pgdat);
7931 free_area_init_core(pgdat);
7934 static void __init free_area_init_memoryless_node(int nid)
7936 free_area_init_node(nid);
7939 #if MAX_NUMNODES > 1
7941 * Figure out the number of possible node ids.
7943 void __init setup_nr_node_ids(void)
7945 unsigned int highest;
7947 highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES);
7948 nr_node_ids = highest + 1;
7953 * node_map_pfn_alignment - determine the maximum internode alignment
7955 * This function should be called after node map is populated and sorted.
7956 * It calculates the maximum power of two alignment which can distinguish
7959 * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
7960 * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)). If the
7961 * nodes are shifted by 256MiB, 256MiB. Note that if only the last node is
7962 * shifted, 1GiB is enough and this function will indicate so.
7964 * This is used to test whether pfn -> nid mapping of the chosen memory
7965 * model has fine enough granularity to avoid incorrect mapping for the
7966 * populated node map.
7968 * Return: the determined alignment in pfn's. 0 if there is no alignment
7969 * requirement (single node).
7971 unsigned long __init node_map_pfn_alignment(void)
7973 unsigned long accl_mask = 0, last_end = 0;
7974 unsigned long start, end, mask;
7975 int last_nid = NUMA_NO_NODE;
7978 for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
7979 if (!start || last_nid < 0 || last_nid == nid) {
7986 * Start with a mask granular enough to pin-point to the
7987 * start pfn and tick off bits one-by-one until it becomes
7988 * too coarse to separate the current node from the last.
7990 mask = ~((1 << __ffs(start)) - 1);
7991 while (mask && last_end <= (start & (mask << 1)))
7994 /* accumulate all internode masks */
7998 /* convert mask to number of pages */
7999 return ~accl_mask + 1;
8003 * early_calculate_totalpages()
8004 * Sum pages in active regions for movable zone.
8005 * Populate N_MEMORY for calculating usable_nodes.
8007 static unsigned long __init early_calculate_totalpages(void)
8009 unsigned long totalpages = 0;
8010 unsigned long start_pfn, end_pfn;
8013 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
8014 unsigned long pages = end_pfn - start_pfn;
8016 totalpages += pages;
8018 node_set_state(nid, N_MEMORY);
8024 * Find the PFN the Movable zone begins in each node. Kernel memory
8025 * is spread evenly between nodes as long as the nodes have enough
8026 * memory. When they don't, some nodes will have more kernelcore than
8029 static void __init find_zone_movable_pfns_for_nodes(void)
8032 unsigned long usable_startpfn;
8033 unsigned long kernelcore_node, kernelcore_remaining;
8034 /* save the state before borrow the nodemask */
8035 nodemask_t saved_node_state = node_states[N_MEMORY];
8036 unsigned long totalpages = early_calculate_totalpages();
8037 int usable_nodes = nodes_weight(node_states[N_MEMORY]);
8038 struct memblock_region *r;
8040 /* Need to find movable_zone earlier when movable_node is specified. */
8041 find_usable_zone_for_movable();
8044 * If movable_node is specified, ignore kernelcore and movablecore
8047 if (movable_node_is_enabled()) {
8048 for_each_mem_region(r) {
8049 if (!memblock_is_hotpluggable(r))
8052 nid = memblock_get_region_node(r);
8054 usable_startpfn = PFN_DOWN(r->base);
8055 zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
8056 min(usable_startpfn, zone_movable_pfn[nid]) :
8064 * If kernelcore=mirror is specified, ignore movablecore option
8066 if (mirrored_kernelcore) {
8067 bool mem_below_4gb_not_mirrored = false;
8069 for_each_mem_region(r) {
8070 if (memblock_is_mirror(r))
8073 nid = memblock_get_region_node(r);
8075 usable_startpfn = memblock_region_memory_base_pfn(r);
8077 if (usable_startpfn < PHYS_PFN(SZ_4G)) {
8078 mem_below_4gb_not_mirrored = true;
8082 zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
8083 min(usable_startpfn, zone_movable_pfn[nid]) :
8087 if (mem_below_4gb_not_mirrored)
8088 pr_warn("This configuration results in unmirrored kernel memory.\n");
8094 * If kernelcore=nn% or movablecore=nn% was specified, calculate the
8095 * amount of necessary memory.
8097 if (required_kernelcore_percent)
8098 required_kernelcore = (totalpages * 100 * required_kernelcore_percent) /
8100 if (required_movablecore_percent)
8101 required_movablecore = (totalpages * 100 * required_movablecore_percent) /
8105 * If movablecore= was specified, calculate what size of
8106 * kernelcore that corresponds so that memory usable for
8107 * any allocation type is evenly spread. If both kernelcore
8108 * and movablecore are specified, then the value of kernelcore
8109 * will be used for required_kernelcore if it's greater than
8110 * what movablecore would have allowed.
8112 if (required_movablecore) {
8113 unsigned long corepages;
8116 * Round-up so that ZONE_MOVABLE is at least as large as what
8117 * was requested by the user
8119 required_movablecore =
8120 roundup(required_movablecore, MAX_ORDER_NR_PAGES);
8121 required_movablecore = min(totalpages, required_movablecore);
8122 corepages = totalpages - required_movablecore;
8124 required_kernelcore = max(required_kernelcore, corepages);
8128 * If kernelcore was not specified or kernelcore size is larger
8129 * than totalpages, there is no ZONE_MOVABLE.
8131 if (!required_kernelcore || required_kernelcore >= totalpages)
8134 /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
8135 usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
8138 /* Spread kernelcore memory as evenly as possible throughout nodes */
8139 kernelcore_node = required_kernelcore / usable_nodes;
8140 for_each_node_state(nid, N_MEMORY) {
8141 unsigned long start_pfn, end_pfn;
8144 * Recalculate kernelcore_node if the division per node
8145 * now exceeds what is necessary to satisfy the requested
8146 * amount of memory for the kernel
8148 if (required_kernelcore < kernelcore_node)
8149 kernelcore_node = required_kernelcore / usable_nodes;
8152 * As the map is walked, we track how much memory is usable
8153 * by the kernel using kernelcore_remaining. When it is
8154 * 0, the rest of the node is usable by ZONE_MOVABLE
8156 kernelcore_remaining = kernelcore_node;
8158 /* Go through each range of PFNs within this node */
8159 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
8160 unsigned long size_pages;
8162 start_pfn = max(start_pfn, zone_movable_pfn[nid]);
8163 if (start_pfn >= end_pfn)
8166 /* Account for what is only usable for kernelcore */
8167 if (start_pfn < usable_startpfn) {
8168 unsigned long kernel_pages;
8169 kernel_pages = min(end_pfn, usable_startpfn)
8172 kernelcore_remaining -= min(kernel_pages,
8173 kernelcore_remaining);
8174 required_kernelcore -= min(kernel_pages,
8175 required_kernelcore);
8177 /* Continue if range is now fully accounted */
8178 if (end_pfn <= usable_startpfn) {
8181 * Push zone_movable_pfn to the end so
8182 * that if we have to rebalance
8183 * kernelcore across nodes, we will
8184 * not double account here
8186 zone_movable_pfn[nid] = end_pfn;
8189 start_pfn = usable_startpfn;
8193 * The usable PFN range for ZONE_MOVABLE is from
8194 * start_pfn->end_pfn. Calculate size_pages as the
8195 * number of pages used as kernelcore
8197 size_pages = end_pfn - start_pfn;
8198 if (size_pages > kernelcore_remaining)
8199 size_pages = kernelcore_remaining;
8200 zone_movable_pfn[nid] = start_pfn + size_pages;
8203 * Some kernelcore has been met, update counts and
8204 * break if the kernelcore for this node has been
8207 required_kernelcore -= min(required_kernelcore,
8209 kernelcore_remaining -= size_pages;
8210 if (!kernelcore_remaining)
8216 * If there is still required_kernelcore, we do another pass with one
8217 * less node in the count. This will push zone_movable_pfn[nid] further
8218 * along on the nodes that still have memory until kernelcore is
8222 if (usable_nodes && required_kernelcore > usable_nodes)
8226 /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
8227 for (nid = 0; nid < MAX_NUMNODES; nid++) {
8228 unsigned long start_pfn, end_pfn;
8230 zone_movable_pfn[nid] =
8231 roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
8233 get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
8234 if (zone_movable_pfn[nid] >= end_pfn)
8235 zone_movable_pfn[nid] = 0;
8239 /* restore the node_state */
8240 node_states[N_MEMORY] = saved_node_state;
8243 /* Any regular or high memory on that node ? */
8244 static void check_for_memory(pg_data_t *pgdat, int nid)
8246 enum zone_type zone_type;
8248 for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
8249 struct zone *zone = &pgdat->node_zones[zone_type];
8250 if (populated_zone(zone)) {
8251 if (IS_ENABLED(CONFIG_HIGHMEM))
8252 node_set_state(nid, N_HIGH_MEMORY);
8253 if (zone_type <= ZONE_NORMAL)
8254 node_set_state(nid, N_NORMAL_MEMORY);
8261 * Some architectures, e.g. ARC may have ZONE_HIGHMEM below ZONE_NORMAL. For
8262 * such cases we allow max_zone_pfn sorted in the descending order
8264 bool __weak arch_has_descending_max_zone_pfns(void)
8270 * free_area_init - Initialise all pg_data_t and zone data
8271 * @max_zone_pfn: an array of max PFNs for each zone
8273 * This will call free_area_init_node() for each active node in the system.
8274 * Using the page ranges provided by memblock_set_node(), the size of each
8275 * zone in each node and their holes is calculated. If the maximum PFN
8276 * between two adjacent zones match, it is assumed that the zone is empty.
8277 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
8278 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
8279 * starts where the previous one ended. For example, ZONE_DMA32 starts
8280 * at arch_max_dma_pfn.
8282 void __init free_area_init(unsigned long *max_zone_pfn)
8284 unsigned long start_pfn, end_pfn;
8288 /* Record where the zone boundaries are */
8289 memset(arch_zone_lowest_possible_pfn, 0,
8290 sizeof(arch_zone_lowest_possible_pfn));
8291 memset(arch_zone_highest_possible_pfn, 0,
8292 sizeof(arch_zone_highest_possible_pfn));
8294 start_pfn = PHYS_PFN(memblock_start_of_DRAM());
8295 descending = arch_has_descending_max_zone_pfns();
8297 for (i = 0; i < MAX_NR_ZONES; i++) {
8299 zone = MAX_NR_ZONES - i - 1;
8303 if (zone == ZONE_MOVABLE)
8306 end_pfn = max(max_zone_pfn[zone], start_pfn);
8307 arch_zone_lowest_possible_pfn[zone] = start_pfn;
8308 arch_zone_highest_possible_pfn[zone] = end_pfn;
8310 start_pfn = end_pfn;
8313 /* Find the PFNs that ZONE_MOVABLE begins at in each node */
8314 memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
8315 find_zone_movable_pfns_for_nodes();
8317 /* Print out the zone ranges */
8318 pr_info("Zone ranges:\n");
8319 for (i = 0; i < MAX_NR_ZONES; i++) {
8320 if (i == ZONE_MOVABLE)
8322 pr_info(" %-8s ", zone_names[i]);
8323 if (arch_zone_lowest_possible_pfn[i] ==
8324 arch_zone_highest_possible_pfn[i])
8327 pr_cont("[mem %#018Lx-%#018Lx]\n",
8328 (u64)arch_zone_lowest_possible_pfn[i]
8330 ((u64)arch_zone_highest_possible_pfn[i]
8331 << PAGE_SHIFT) - 1);
8334 /* Print out the PFNs ZONE_MOVABLE begins at in each node */
8335 pr_info("Movable zone start for each node\n");
8336 for (i = 0; i < MAX_NUMNODES; i++) {
8337 if (zone_movable_pfn[i])
8338 pr_info(" Node %d: %#018Lx\n", i,
8339 (u64)zone_movable_pfn[i] << PAGE_SHIFT);
8343 * Print out the early node map, and initialize the
8344 * subsection-map relative to active online memory ranges to
8345 * enable future "sub-section" extensions of the memory map.
8347 pr_info("Early memory node ranges\n");
8348 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
8349 pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid,
8350 (u64)start_pfn << PAGE_SHIFT,
8351 ((u64)end_pfn << PAGE_SHIFT) - 1);
8352 subsection_map_init(start_pfn, end_pfn - start_pfn);
8355 /* Initialise every node */
8356 mminit_verify_pageflags_layout();
8357 setup_nr_node_ids();
8358 for_each_node(nid) {
8361 if (!node_online(nid)) {
8362 pr_info("Initializing node %d as memoryless\n", nid);
8364 /* Allocator not initialized yet */
8365 pgdat = arch_alloc_nodedata(nid);
8367 pr_err("Cannot allocate %zuB for node %d.\n",
8368 sizeof(*pgdat), nid);
8371 arch_refresh_nodedata(nid, pgdat);
8372 free_area_init_memoryless_node(nid);
8375 * We do not want to confuse userspace by sysfs
8376 * files/directories for node without any memory
8377 * attached to it, so this node is not marked as
8378 * N_MEMORY and not marked online so that no sysfs
8379 * hierarchy will be created via register_one_node for
8380 * it. The pgdat will get fully initialized by
8381 * hotadd_init_pgdat() when memory is hotplugged into
8387 pgdat = NODE_DATA(nid);
8388 free_area_init_node(nid);
8390 /* Any memory on that node */
8391 if (pgdat->node_present_pages)
8392 node_set_state(nid, N_MEMORY);
8393 check_for_memory(pgdat, nid);
8399 static int __init cmdline_parse_core(char *p, unsigned long *core,
8400 unsigned long *percent)
8402 unsigned long long coremem;
8408 /* Value may be a percentage of total memory, otherwise bytes */
8409 coremem = simple_strtoull(p, &endptr, 0);
8410 if (*endptr == '%') {
8411 /* Paranoid check for percent values greater than 100 */
8412 WARN_ON(coremem > 100);
8416 coremem = memparse(p, &p);
8417 /* Paranoid check that UL is enough for the coremem value */
8418 WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
8420 *core = coremem >> PAGE_SHIFT;
8427 * kernelcore=size sets the amount of memory for use for allocations that
8428 * cannot be reclaimed or migrated.
8430 static int __init cmdline_parse_kernelcore(char *p)
8432 /* parse kernelcore=mirror */
8433 if (parse_option_str(p, "mirror")) {
8434 mirrored_kernelcore = true;
8438 return cmdline_parse_core(p, &required_kernelcore,
8439 &required_kernelcore_percent);
8443 * movablecore=size sets the amount of memory for use for allocations that
8444 * can be reclaimed or migrated.
8446 static int __init cmdline_parse_movablecore(char *p)
8448 return cmdline_parse_core(p, &required_movablecore,
8449 &required_movablecore_percent);
8452 early_param("kernelcore", cmdline_parse_kernelcore);
8453 early_param("movablecore", cmdline_parse_movablecore);
8455 void adjust_managed_page_count(struct page *page, long count)
8457 atomic_long_add(count, &page_zone(page)->managed_pages);
8458 totalram_pages_add(count);
8459 #ifdef CONFIG_HIGHMEM
8460 if (PageHighMem(page))
8461 totalhigh_pages_add(count);
8464 EXPORT_SYMBOL(adjust_managed_page_count);
8466 unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
8469 unsigned long pages = 0;
8471 start = (void *)PAGE_ALIGN((unsigned long)start);
8472 end = (void *)((unsigned long)end & PAGE_MASK);
8473 for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
8474 struct page *page = virt_to_page(pos);
8475 void *direct_map_addr;
8478 * 'direct_map_addr' might be different from 'pos'
8479 * because some architectures' virt_to_page()
8480 * work with aliases. Getting the direct map
8481 * address ensures that we get a _writeable_
8482 * alias for the memset().
8484 direct_map_addr = page_address(page);
8486 * Perform a kasan-unchecked memset() since this memory
8487 * has not been initialized.
8489 direct_map_addr = kasan_reset_tag(direct_map_addr);
8490 if ((unsigned int)poison <= 0xFF)
8491 memset(direct_map_addr, poison, PAGE_SIZE);
8493 free_reserved_page(page);
8497 pr_info("Freeing %s memory: %ldK\n", s, K(pages));
8502 void __init mem_init_print_info(void)
8504 unsigned long physpages, codesize, datasize, rosize, bss_size;
8505 unsigned long init_code_size, init_data_size;
8507 physpages = get_num_physpages();
8508 codesize = _etext - _stext;
8509 datasize = _edata - _sdata;
8510 rosize = __end_rodata - __start_rodata;
8511 bss_size = __bss_stop - __bss_start;
8512 init_data_size = __init_end - __init_begin;
8513 init_code_size = _einittext - _sinittext;
8516 * Detect special cases and adjust section sizes accordingly:
8517 * 1) .init.* may be embedded into .data sections
8518 * 2) .init.text.* may be out of [__init_begin, __init_end],
8519 * please refer to arch/tile/kernel/vmlinux.lds.S.
8520 * 3) .rodata.* may be embedded into .text or .data sections.
8522 #define adj_init_size(start, end, size, pos, adj) \
8524 if (&start[0] <= &pos[0] && &pos[0] < &end[0] && size > adj) \
8528 adj_init_size(__init_begin, __init_end, init_data_size,
8529 _sinittext, init_code_size);
8530 adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
8531 adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
8532 adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
8533 adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
8535 #undef adj_init_size
8537 pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
8538 #ifdef CONFIG_HIGHMEM
8542 K(nr_free_pages()), K(physpages),
8543 codesize / SZ_1K, datasize / SZ_1K, rosize / SZ_1K,
8544 (init_data_size + init_code_size) / SZ_1K, bss_size / SZ_1K,
8545 K(physpages - totalram_pages() - totalcma_pages),
8547 #ifdef CONFIG_HIGHMEM
8548 , K(totalhigh_pages())
8554 * set_dma_reserve - set the specified number of pages reserved in the first zone
8555 * @new_dma_reserve: The number of pages to mark reserved
8557 * The per-cpu batchsize and zone watermarks are determined by managed_pages.
8558 * In the DMA zone, a significant percentage may be consumed by kernel image
8559 * and other unfreeable allocations which can skew the watermarks badly. This
8560 * function may optionally be used to account for unfreeable pages in the
8561 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
8562 * smaller per-cpu batchsize.
8564 void __init set_dma_reserve(unsigned long new_dma_reserve)
8566 dma_reserve = new_dma_reserve;
8569 static int page_alloc_cpu_dead(unsigned int cpu)
8573 lru_add_drain_cpu(cpu);
8574 mlock_page_drain_remote(cpu);
8578 * Spill the event counters of the dead processor
8579 * into the current processors event counters.
8580 * This artificially elevates the count of the current
8583 vm_events_fold_cpu(cpu);
8586 * Zero the differential counters of the dead processor
8587 * so that the vm statistics are consistent.
8589 * This is only okay since the processor is dead and cannot
8590 * race with what we are doing.
8592 cpu_vm_stats_fold(cpu);
8594 for_each_populated_zone(zone)
8595 zone_pcp_update(zone, 0);
8600 static int page_alloc_cpu_online(unsigned int cpu)
8604 for_each_populated_zone(zone)
8605 zone_pcp_update(zone, 1);
8610 int hashdist = HASHDIST_DEFAULT;
8612 static int __init set_hashdist(char *str)
8616 hashdist = simple_strtoul(str, &str, 0);
8619 __setup("hashdist=", set_hashdist);
8622 void __init page_alloc_init(void)
8627 if (num_node_state(N_MEMORY) == 1)
8631 ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC,
8632 "mm/page_alloc:pcp",
8633 page_alloc_cpu_online,
8634 page_alloc_cpu_dead);
8639 * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio
8640 * or min_free_kbytes changes.
8642 static void calculate_totalreserve_pages(void)
8644 struct pglist_data *pgdat;
8645 unsigned long reserve_pages = 0;
8646 enum zone_type i, j;
8648 for_each_online_pgdat(pgdat) {
8650 pgdat->totalreserve_pages = 0;
8652 for (i = 0; i < MAX_NR_ZONES; i++) {
8653 struct zone *zone = pgdat->node_zones + i;
8655 unsigned long managed_pages = zone_managed_pages(zone);
8657 /* Find valid and maximum lowmem_reserve in the zone */
8658 for (j = i; j < MAX_NR_ZONES; j++) {
8659 if (zone->lowmem_reserve[j] > max)
8660 max = zone->lowmem_reserve[j];
8663 /* we treat the high watermark as reserved pages. */
8664 max += high_wmark_pages(zone);
8666 if (max > managed_pages)
8667 max = managed_pages;
8669 pgdat->totalreserve_pages += max;
8671 reserve_pages += max;
8674 totalreserve_pages = reserve_pages;
8678 * setup_per_zone_lowmem_reserve - called whenever
8679 * sysctl_lowmem_reserve_ratio changes. Ensures that each zone
8680 * has a correct pages reserved value, so an adequate number of
8681 * pages are left in the zone after a successful __alloc_pages().
8683 static void setup_per_zone_lowmem_reserve(void)
8685 struct pglist_data *pgdat;
8686 enum zone_type i, j;
8688 for_each_online_pgdat(pgdat) {
8689 for (i = 0; i < MAX_NR_ZONES - 1; i++) {
8690 struct zone *zone = &pgdat->node_zones[i];
8691 int ratio = sysctl_lowmem_reserve_ratio[i];
8692 bool clear = !ratio || !zone_managed_pages(zone);
8693 unsigned long managed_pages = 0;
8695 for (j = i + 1; j < MAX_NR_ZONES; j++) {
8696 struct zone *upper_zone = &pgdat->node_zones[j];
8698 managed_pages += zone_managed_pages(upper_zone);
8701 zone->lowmem_reserve[j] = 0;
8703 zone->lowmem_reserve[j] = managed_pages / ratio;
8708 /* update totalreserve_pages */
8709 calculate_totalreserve_pages();
8712 static void __setup_per_zone_wmarks(void)
8714 unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
8715 unsigned long lowmem_pages = 0;
8717 unsigned long flags;
8719 /* Calculate total number of !ZONE_HIGHMEM pages */
8720 for_each_zone(zone) {
8721 if (!is_highmem(zone))
8722 lowmem_pages += zone_managed_pages(zone);
8725 for_each_zone(zone) {
8728 spin_lock_irqsave(&zone->lock, flags);
8729 tmp = (u64)pages_min * zone_managed_pages(zone);
8730 do_div(tmp, lowmem_pages);
8731 if (is_highmem(zone)) {
8733 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
8734 * need highmem pages, so cap pages_min to a small
8737 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
8738 * deltas control async page reclaim, and so should
8739 * not be capped for highmem.
8741 unsigned long min_pages;
8743 min_pages = zone_managed_pages(zone) / 1024;
8744 min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
8745 zone->_watermark[WMARK_MIN] = min_pages;
8748 * If it's a lowmem zone, reserve a number of pages
8749 * proportionate to the zone's size.
8751 zone->_watermark[WMARK_MIN] = tmp;
8755 * Set the kswapd watermarks distance according to the
8756 * scale factor in proportion to available memory, but
8757 * ensure a minimum size on small systems.
8759 tmp = max_t(u64, tmp >> 2,
8760 mult_frac(zone_managed_pages(zone),
8761 watermark_scale_factor, 10000));
8763 zone->watermark_boost = 0;
8764 zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp;
8765 zone->_watermark[WMARK_HIGH] = low_wmark_pages(zone) + tmp;
8766 zone->_watermark[WMARK_PROMO] = high_wmark_pages(zone) + tmp;
8768 spin_unlock_irqrestore(&zone->lock, flags);
8771 /* update totalreserve_pages */
8772 calculate_totalreserve_pages();
8776 * setup_per_zone_wmarks - called when min_free_kbytes changes
8777 * or when memory is hot-{added|removed}
8779 * Ensures that the watermark[min,low,high] values for each zone are set
8780 * correctly with respect to min_free_kbytes.
8782 void setup_per_zone_wmarks(void)
8785 static DEFINE_SPINLOCK(lock);
8788 __setup_per_zone_wmarks();
8792 * The watermark size have changed so update the pcpu batch
8793 * and high limits or the limits may be inappropriate.
8796 zone_pcp_update(zone, 0);
8800 * Initialise min_free_kbytes.
8802 * For small machines we want it small (128k min). For large machines
8803 * we want it large (256MB max). But it is not linear, because network
8804 * bandwidth does not increase linearly with machine size. We use
8806 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
8807 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
8823 void calculate_min_free_kbytes(void)
8825 unsigned long lowmem_kbytes;
8826 int new_min_free_kbytes;
8828 lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
8829 new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
8831 if (new_min_free_kbytes > user_min_free_kbytes)
8832 min_free_kbytes = clamp(new_min_free_kbytes, 128, 262144);
8834 pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
8835 new_min_free_kbytes, user_min_free_kbytes);
8839 int __meminit init_per_zone_wmark_min(void)
8841 calculate_min_free_kbytes();
8842 setup_per_zone_wmarks();
8843 refresh_zone_stat_thresholds();
8844 setup_per_zone_lowmem_reserve();
8847 setup_min_unmapped_ratio();
8848 setup_min_slab_ratio();
8851 khugepaged_min_free_kbytes_update();
8855 postcore_initcall(init_per_zone_wmark_min)
8858 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
8859 * that we can call two helper functions whenever min_free_kbytes
8862 int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
8863 void *buffer, size_t *length, loff_t *ppos)
8867 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
8872 user_min_free_kbytes = min_free_kbytes;
8873 setup_per_zone_wmarks();
8878 int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
8879 void *buffer, size_t *length, loff_t *ppos)
8883 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
8888 setup_per_zone_wmarks();
8894 static void setup_min_unmapped_ratio(void)
8899 for_each_online_pgdat(pgdat)
8900 pgdat->min_unmapped_pages = 0;
8903 zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) *
8904 sysctl_min_unmapped_ratio) / 100;
8908 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
8909 void *buffer, size_t *length, loff_t *ppos)
8913 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
8917 setup_min_unmapped_ratio();
8922 static void setup_min_slab_ratio(void)
8927 for_each_online_pgdat(pgdat)
8928 pgdat->min_slab_pages = 0;
8931 zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) *
8932 sysctl_min_slab_ratio) / 100;
8935 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
8936 void *buffer, size_t *length, loff_t *ppos)
8940 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
8944 setup_min_slab_ratio();
8951 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
8952 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
8953 * whenever sysctl_lowmem_reserve_ratio changes.
8955 * The reserve ratio obviously has absolutely no relation with the
8956 * minimum watermarks. The lowmem reserve ratio can only make sense
8957 * if in function of the boot time zone sizes.
8959 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
8960 void *buffer, size_t *length, loff_t *ppos)
8964 proc_dointvec_minmax(table, write, buffer, length, ppos);
8966 for (i = 0; i < MAX_NR_ZONES; i++) {
8967 if (sysctl_lowmem_reserve_ratio[i] < 1)
8968 sysctl_lowmem_reserve_ratio[i] = 0;
8971 setup_per_zone_lowmem_reserve();
8976 * percpu_pagelist_high_fraction - changes the pcp->high for each zone on each
8977 * cpu. It is the fraction of total pages in each zone that a hot per cpu
8978 * pagelist can have before it gets flushed back to buddy allocator.
8980 int percpu_pagelist_high_fraction_sysctl_handler(struct ctl_table *table,
8981 int write, void *buffer, size_t *length, loff_t *ppos)
8984 int old_percpu_pagelist_high_fraction;
8987 mutex_lock(&pcp_batch_high_lock);
8988 old_percpu_pagelist_high_fraction = percpu_pagelist_high_fraction;
8990 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
8991 if (!write || ret < 0)
8994 /* Sanity checking to avoid pcp imbalance */
8995 if (percpu_pagelist_high_fraction &&
8996 percpu_pagelist_high_fraction < MIN_PERCPU_PAGELIST_HIGH_FRACTION) {
8997 percpu_pagelist_high_fraction = old_percpu_pagelist_high_fraction;
9003 if (percpu_pagelist_high_fraction == old_percpu_pagelist_high_fraction)
9006 for_each_populated_zone(zone)
9007 zone_set_pageset_high_and_batch(zone, 0);
9009 mutex_unlock(&pcp_batch_high_lock);
9013 #ifndef __HAVE_ARCH_RESERVED_KERNEL_PAGES
9015 * Returns the number of pages that arch has reserved but
9016 * is not known to alloc_large_system_hash().
9018 static unsigned long __init arch_reserved_kernel_pages(void)
9025 * Adaptive scale is meant to reduce sizes of hash tables on large memory
9026 * machines. As memory size is increased the scale is also increased but at
9027 * slower pace. Starting from ADAPT_SCALE_BASE (64G), every time memory
9028 * quadruples the scale is increased by one, which means the size of hash table
9029 * only doubles, instead of quadrupling as well.
9030 * Because 32-bit systems cannot have large physical memory, where this scaling
9031 * makes sense, it is disabled on such platforms.
9033 #if __BITS_PER_LONG > 32
9034 #define ADAPT_SCALE_BASE (64ul << 30)
9035 #define ADAPT_SCALE_SHIFT 2
9036 #define ADAPT_SCALE_NPAGES (ADAPT_SCALE_BASE >> PAGE_SHIFT)
9040 * allocate a large system hash table from bootmem
9041 * - it is assumed that the hash table must contain an exact power-of-2
9042 * quantity of entries
9043 * - limit is the number of hash buckets, not the total allocation size
9045 void *__init alloc_large_system_hash(const char *tablename,
9046 unsigned long bucketsize,
9047 unsigned long numentries,
9050 unsigned int *_hash_shift,
9051 unsigned int *_hash_mask,
9052 unsigned long low_limit,
9053 unsigned long high_limit)
9055 unsigned long long max = high_limit;
9056 unsigned long log2qty, size;
9062 /* allow the kernel cmdline to have a say */
9064 /* round applicable memory size up to nearest megabyte */
9065 numentries = nr_kernel_pages;
9066 numentries -= arch_reserved_kernel_pages();
9068 /* It isn't necessary when PAGE_SIZE >= 1MB */
9069 if (PAGE_SIZE < SZ_1M)
9070 numentries = round_up(numentries, SZ_1M / PAGE_SIZE);
9072 #if __BITS_PER_LONG > 32
9074 unsigned long adapt;
9076 for (adapt = ADAPT_SCALE_NPAGES; adapt < numentries;
9077 adapt <<= ADAPT_SCALE_SHIFT)
9082 /* limit to 1 bucket per 2^scale bytes of low memory */
9083 if (scale > PAGE_SHIFT)
9084 numentries >>= (scale - PAGE_SHIFT);
9086 numentries <<= (PAGE_SHIFT - scale);
9088 /* Make sure we've got at least a 0-order allocation.. */
9089 if (unlikely(flags & HASH_SMALL)) {
9090 /* Makes no sense without HASH_EARLY */
9091 WARN_ON(!(flags & HASH_EARLY));
9092 if (!(numentries >> *_hash_shift)) {
9093 numentries = 1UL << *_hash_shift;
9094 BUG_ON(!numentries);
9096 } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
9097 numentries = PAGE_SIZE / bucketsize;
9099 numentries = roundup_pow_of_two(numentries);
9101 /* limit allocation size to 1/16 total memory by default */
9103 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
9104 do_div(max, bucketsize);
9106 max = min(max, 0x80000000ULL);
9108 if (numentries < low_limit)
9109 numentries = low_limit;
9110 if (numentries > max)
9113 log2qty = ilog2(numentries);
9115 gfp_flags = (flags & HASH_ZERO) ? GFP_ATOMIC | __GFP_ZERO : GFP_ATOMIC;
9118 size = bucketsize << log2qty;
9119 if (flags & HASH_EARLY) {
9120 if (flags & HASH_ZERO)
9121 table = memblock_alloc(size, SMP_CACHE_BYTES);
9123 table = memblock_alloc_raw(size,
9125 } else if (get_order(size) >= MAX_ORDER || hashdist) {
9126 table = vmalloc_huge(size, gfp_flags);
9129 huge = is_vm_area_hugepages(table);
9132 * If bucketsize is not a power-of-two, we may free
9133 * some pages at the end of hash table which
9134 * alloc_pages_exact() automatically does
9136 table = alloc_pages_exact(size, gfp_flags);
9137 kmemleak_alloc(table, size, 1, gfp_flags);
9139 } while (!table && size > PAGE_SIZE && --log2qty);
9142 panic("Failed to allocate %s hash table\n", tablename);
9144 pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
9145 tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
9146 virt ? (huge ? "vmalloc hugepage" : "vmalloc") : "linear");
9149 *_hash_shift = log2qty;
9151 *_hash_mask = (1 << log2qty) - 1;
9156 #ifdef CONFIG_CONTIG_ALLOC
9157 #if defined(CONFIG_DYNAMIC_DEBUG) || \
9158 (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
9159 /* Usage: See admin-guide/dynamic-debug-howto.rst */
9160 static void alloc_contig_dump_pages(struct list_head *page_list)
9162 DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, "migrate failure");
9164 if (DYNAMIC_DEBUG_BRANCH(descriptor)) {
9168 list_for_each_entry(page, page_list, lru)
9169 dump_page(page, "migration failure");
9173 static inline void alloc_contig_dump_pages(struct list_head *page_list)
9178 /* [start, end) must belong to a single zone. */
9179 int __alloc_contig_migrate_range(struct compact_control *cc,
9180 unsigned long start, unsigned long end)
9182 /* This function is based on compact_zone() from compaction.c. */
9183 unsigned int nr_reclaimed;
9184 unsigned long pfn = start;
9185 unsigned int tries = 0;
9187 struct migration_target_control mtc = {
9188 .nid = zone_to_nid(cc->zone),
9189 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
9192 lru_cache_disable();
9194 while (pfn < end || !list_empty(&cc->migratepages)) {
9195 if (fatal_signal_pending(current)) {
9200 if (list_empty(&cc->migratepages)) {
9201 cc->nr_migratepages = 0;
9202 ret = isolate_migratepages_range(cc, pfn, end);
9203 if (ret && ret != -EAGAIN)
9205 pfn = cc->migrate_pfn;
9207 } else if (++tries == 5) {
9212 nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
9214 cc->nr_migratepages -= nr_reclaimed;
9216 ret = migrate_pages(&cc->migratepages, alloc_migration_target,
9217 NULL, (unsigned long)&mtc, cc->mode, MR_CONTIG_RANGE, NULL);
9220 * On -ENOMEM, migrate_pages() bails out right away. It is pointless
9221 * to retry again over this error, so do the same here.
9229 if (!(cc->gfp_mask & __GFP_NOWARN) && ret == -EBUSY)
9230 alloc_contig_dump_pages(&cc->migratepages);
9231 putback_movable_pages(&cc->migratepages);
9238 * alloc_contig_range() -- tries to allocate given range of pages
9239 * @start: start PFN to allocate
9240 * @end: one-past-the-last PFN to allocate
9241 * @migratetype: migratetype of the underlying pageblocks (either
9242 * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks
9243 * in range must have the same migratetype and it must
9244 * be either of the two.
9245 * @gfp_mask: GFP mask to use during compaction
9247 * The PFN range does not have to be pageblock aligned. The PFN range must
9248 * belong to a single zone.
9250 * The first thing this routine does is attempt to MIGRATE_ISOLATE all
9251 * pageblocks in the range. Once isolated, the pageblocks should not
9252 * be modified by others.
9254 * Return: zero on success or negative error code. On success all
9255 * pages which PFN is in [start, end) are allocated for the caller and
9256 * need to be freed with free_contig_range().
9258 int alloc_contig_range(unsigned long start, unsigned long end,
9259 unsigned migratetype, gfp_t gfp_mask)
9261 unsigned long outer_start, outer_end;
9265 struct compact_control cc = {
9266 .nr_migratepages = 0,
9268 .zone = page_zone(pfn_to_page(start)),
9269 .mode = MIGRATE_SYNC,
9270 .ignore_skip_hint = true,
9271 .no_set_skip_hint = true,
9272 .gfp_mask = current_gfp_context(gfp_mask),
9273 .alloc_contig = true,
9275 INIT_LIST_HEAD(&cc.migratepages);
9278 * What we do here is we mark all pageblocks in range as
9279 * MIGRATE_ISOLATE. Because pageblock and max order pages may
9280 * have different sizes, and due to the way page allocator
9281 * work, start_isolate_page_range() has special handlings for this.
9283 * Once the pageblocks are marked as MIGRATE_ISOLATE, we
9284 * migrate the pages from an unaligned range (ie. pages that
9285 * we are interested in). This will put all the pages in
9286 * range back to page allocator as MIGRATE_ISOLATE.
9288 * When this is done, we take the pages in range from page
9289 * allocator removing them from the buddy system. This way
9290 * page allocator will never consider using them.
9292 * This lets us mark the pageblocks back as
9293 * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
9294 * aligned range but not in the unaligned, original range are
9295 * put back to page allocator so that buddy can use them.
9298 ret = start_isolate_page_range(start, end, migratetype, 0, gfp_mask);
9302 drain_all_pages(cc.zone);
9305 * In case of -EBUSY, we'd like to know which page causes problem.
9306 * So, just fall through. test_pages_isolated() has a tracepoint
9307 * which will report the busy page.
9309 * It is possible that busy pages could become available before
9310 * the call to test_pages_isolated, and the range will actually be
9311 * allocated. So, if we fall through be sure to clear ret so that
9312 * -EBUSY is not accidentally used or returned to caller.
9314 ret = __alloc_contig_migrate_range(&cc, start, end);
9315 if (ret && ret != -EBUSY)
9320 * Pages from [start, end) are within a pageblock_nr_pages
9321 * aligned blocks that are marked as MIGRATE_ISOLATE. What's
9322 * more, all pages in [start, end) are free in page allocator.
9323 * What we are going to do is to allocate all pages from
9324 * [start, end) (that is remove them from page allocator).
9326 * The only problem is that pages at the beginning and at the
9327 * end of interesting range may be not aligned with pages that
9328 * page allocator holds, ie. they can be part of higher order
9329 * pages. Because of this, we reserve the bigger range and
9330 * once this is done free the pages we are not interested in.
9332 * We don't have to hold zone->lock here because the pages are
9333 * isolated thus they won't get removed from buddy.
9337 outer_start = start;
9338 while (!PageBuddy(pfn_to_page(outer_start))) {
9339 if (++order >= MAX_ORDER) {
9340 outer_start = start;
9343 outer_start &= ~0UL << order;
9346 if (outer_start != start) {
9347 order = buddy_order(pfn_to_page(outer_start));
9350 * outer_start page could be small order buddy page and
9351 * it doesn't include start page. Adjust outer_start
9352 * in this case to report failed page properly
9353 * on tracepoint in test_pages_isolated()
9355 if (outer_start + (1UL << order) <= start)
9356 outer_start = start;
9359 /* Make sure the range is really isolated. */
9360 if (test_pages_isolated(outer_start, end, 0)) {
9365 /* Grab isolated pages from freelists. */
9366 outer_end = isolate_freepages_range(&cc, outer_start, end);
9372 /* Free head and tail (if any) */
9373 if (start != outer_start)
9374 free_contig_range(outer_start, start - outer_start);
9375 if (end != outer_end)
9376 free_contig_range(end, outer_end - end);
9379 undo_isolate_page_range(start, end, migratetype);
9382 EXPORT_SYMBOL(alloc_contig_range);
9384 static int __alloc_contig_pages(unsigned long start_pfn,
9385 unsigned long nr_pages, gfp_t gfp_mask)
9387 unsigned long end_pfn = start_pfn + nr_pages;
9389 return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
9393 static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
9394 unsigned long nr_pages)
9396 unsigned long i, end_pfn = start_pfn + nr_pages;
9399 for (i = start_pfn; i < end_pfn; i++) {
9400 page = pfn_to_online_page(i);
9404 if (page_zone(page) != z)
9407 if (PageReserved(page))
9413 static bool zone_spans_last_pfn(const struct zone *zone,
9414 unsigned long start_pfn, unsigned long nr_pages)
9416 unsigned long last_pfn = start_pfn + nr_pages - 1;
9418 return zone_spans_pfn(zone, last_pfn);
9422 * alloc_contig_pages() -- tries to find and allocate contiguous range of pages
9423 * @nr_pages: Number of contiguous pages to allocate
9424 * @gfp_mask: GFP mask to limit search and used during compaction
9426 * @nodemask: Mask for other possible nodes
9428 * This routine is a wrapper around alloc_contig_range(). It scans over zones
9429 * on an applicable zonelist to find a contiguous pfn range which can then be
9430 * tried for allocation with alloc_contig_range(). This routine is intended
9431 * for allocation requests which can not be fulfilled with the buddy allocator.
9433 * The allocated memory is always aligned to a page boundary. If nr_pages is a
9434 * power of two, then allocated range is also guaranteed to be aligned to same
9435 * nr_pages (e.g. 1GB request would be aligned to 1GB).
9437 * Allocated pages can be freed with free_contig_range() or by manually calling
9438 * __free_page() on each allocated page.
9440 * Return: pointer to contiguous pages on success, or NULL if not successful.
9442 struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask,
9443 int nid, nodemask_t *nodemask)
9445 unsigned long ret, pfn, flags;
9446 struct zonelist *zonelist;
9450 zonelist = node_zonelist(nid, gfp_mask);
9451 for_each_zone_zonelist_nodemask(zone, z, zonelist,
9452 gfp_zone(gfp_mask), nodemask) {
9453 spin_lock_irqsave(&zone->lock, flags);
9455 pfn = ALIGN(zone->zone_start_pfn, nr_pages);
9456 while (zone_spans_last_pfn(zone, pfn, nr_pages)) {
9457 if (pfn_range_valid_contig(zone, pfn, nr_pages)) {
9459 * We release the zone lock here because
9460 * alloc_contig_range() will also lock the zone
9461 * at some point. If there's an allocation
9462 * spinning on this lock, it may win the race
9463 * and cause alloc_contig_range() to fail...
9465 spin_unlock_irqrestore(&zone->lock, flags);
9466 ret = __alloc_contig_pages(pfn, nr_pages,
9469 return pfn_to_page(pfn);
9470 spin_lock_irqsave(&zone->lock, flags);
9474 spin_unlock_irqrestore(&zone->lock, flags);
9478 #endif /* CONFIG_CONTIG_ALLOC */
9480 void free_contig_range(unsigned long pfn, unsigned long nr_pages)
9482 unsigned long count = 0;
9484 for (; nr_pages--; pfn++) {
9485 struct page *page = pfn_to_page(pfn);
9487 count += page_count(page) != 1;
9490 WARN(count != 0, "%lu pages are still in use!\n", count);
9492 EXPORT_SYMBOL(free_contig_range);
9495 * Effectively disable pcplists for the zone by setting the high limit to 0
9496 * and draining all cpus. A concurrent page freeing on another CPU that's about
9497 * to put the page on pcplist will either finish before the drain and the page
9498 * will be drained, or observe the new high limit and skip the pcplist.
9500 * Must be paired with a call to zone_pcp_enable().
9502 void zone_pcp_disable(struct zone *zone)
9504 mutex_lock(&pcp_batch_high_lock);
9505 __zone_set_pageset_high_and_batch(zone, 0, 1);
9506 __drain_all_pages(zone, true);
9509 void zone_pcp_enable(struct zone *zone)
9511 __zone_set_pageset_high_and_batch(zone, zone->pageset_high, zone->pageset_batch);
9512 mutex_unlock(&pcp_batch_high_lock);
9515 void zone_pcp_reset(struct zone *zone)
9518 struct per_cpu_zonestat *pzstats;
9520 if (zone->per_cpu_pageset != &boot_pageset) {
9521 for_each_online_cpu(cpu) {
9522 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
9523 drain_zonestat(zone, pzstats);
9525 free_percpu(zone->per_cpu_pageset);
9526 zone->per_cpu_pageset = &boot_pageset;
9527 if (zone->per_cpu_zonestats != &boot_zonestats) {
9528 free_percpu(zone->per_cpu_zonestats);
9529 zone->per_cpu_zonestats = &boot_zonestats;
9534 #ifdef CONFIG_MEMORY_HOTREMOVE
9536 * All pages in the range must be in a single zone, must not contain holes,
9537 * must span full sections, and must be isolated before calling this function.
9539 void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
9541 unsigned long pfn = start_pfn;
9545 unsigned long flags;
9547 offline_mem_sections(pfn, end_pfn);
9548 zone = page_zone(pfn_to_page(pfn));
9549 spin_lock_irqsave(&zone->lock, flags);
9550 while (pfn < end_pfn) {
9551 page = pfn_to_page(pfn);
9553 * The HWPoisoned page may be not in buddy system, and
9554 * page_count() is not 0.
9556 if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
9561 * At this point all remaining PageOffline() pages have a
9562 * reference count of 0 and can simply be skipped.
9564 if (PageOffline(page)) {
9565 BUG_ON(page_count(page));
9566 BUG_ON(PageBuddy(page));
9571 BUG_ON(page_count(page));
9572 BUG_ON(!PageBuddy(page));
9573 order = buddy_order(page);
9574 del_page_from_free_list(page, zone, order);
9575 pfn += (1 << order);
9577 spin_unlock_irqrestore(&zone->lock, flags);
9582 * This function returns a stable result only if called under zone lock.
9584 bool is_free_buddy_page(struct page *page)
9586 unsigned long pfn = page_to_pfn(page);
9589 for (order = 0; order < MAX_ORDER; order++) {
9590 struct page *page_head = page - (pfn & ((1 << order) - 1));
9592 if (PageBuddy(page_head) &&
9593 buddy_order_unsafe(page_head) >= order)
9597 return order < MAX_ORDER;
9599 EXPORT_SYMBOL(is_free_buddy_page);
9601 #ifdef CONFIG_MEMORY_FAILURE
9603 * Break down a higher-order page in sub-pages, and keep our target out of
9606 static void break_down_buddy_pages(struct zone *zone, struct page *page,
9607 struct page *target, int low, int high,
9610 unsigned long size = 1 << high;
9611 struct page *current_buddy, *next_page;
9613 while (high > low) {
9617 if (target >= &page[size]) {
9618 next_page = page + size;
9619 current_buddy = page;
9622 current_buddy = page + size;
9625 if (set_page_guard(zone, current_buddy, high, migratetype))
9628 if (current_buddy != target) {
9629 add_to_free_list(current_buddy, zone, high, migratetype);
9630 set_buddy_order(current_buddy, high);
9637 * Take a page that will be marked as poisoned off the buddy allocator.
9639 bool take_page_off_buddy(struct page *page)
9641 struct zone *zone = page_zone(page);
9642 unsigned long pfn = page_to_pfn(page);
9643 unsigned long flags;
9647 spin_lock_irqsave(&zone->lock, flags);
9648 for (order = 0; order < MAX_ORDER; order++) {
9649 struct page *page_head = page - (pfn & ((1 << order) - 1));
9650 int page_order = buddy_order(page_head);
9652 if (PageBuddy(page_head) && page_order >= order) {
9653 unsigned long pfn_head = page_to_pfn(page_head);
9654 int migratetype = get_pfnblock_migratetype(page_head,
9657 del_page_from_free_list(page_head, zone, page_order);
9658 break_down_buddy_pages(zone, page_head, page, 0,
9659 page_order, migratetype);
9660 SetPageHWPoisonTakenOff(page);
9661 if (!is_migrate_isolate(migratetype))
9662 __mod_zone_freepage_state(zone, -1, migratetype);
9666 if (page_count(page_head) > 0)
9669 spin_unlock_irqrestore(&zone->lock, flags);
9674 * Cancel takeoff done by take_page_off_buddy().
9676 bool put_page_back_buddy(struct page *page)
9678 struct zone *zone = page_zone(page);
9679 unsigned long pfn = page_to_pfn(page);
9680 unsigned long flags;
9681 int migratetype = get_pfnblock_migratetype(page, pfn);
9684 spin_lock_irqsave(&zone->lock, flags);
9685 if (put_page_testzero(page)) {
9686 ClearPageHWPoisonTakenOff(page);
9687 __free_one_page(page, pfn, zone, 0, migratetype, FPI_NONE);
9688 if (TestClearPageHWPoison(page)) {
9692 spin_unlock_irqrestore(&zone->lock, flags);
9698 #ifdef CONFIG_ZONE_DMA
9699 bool has_managed_dma(void)
9701 struct pglist_data *pgdat;
9703 for_each_online_pgdat(pgdat) {
9704 struct zone *zone = &pgdat->node_zones[ZONE_DMA];
9706 if (managed_zone(zone))
9711 #endif /* CONFIG_ZONE_DMA */