// SPDX-License-Identifier: GPL-2.0-only /* * linux/mm/page_alloc.c * * Manages the free list, the system allocates free pages here. * Note that kmalloc() lives in slab.c * * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds * Swap reorganised 29.12.95, Stephen Tweedie * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 * Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999 * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999 * Zone balancing, Kanoj Sarcar, SGI, Jan 2000 * Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002 * (lots of bits borrowed from Ingo Molnar & Andrew Morton) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "internal.h" #include "shuffle.h" #include "page_reporting.h" /* Free Page Internal flags: for internal, non-pcp variants of free_pages(). */ typedef int __bitwise fpi_t; /* No special request */ #define FPI_NONE ((__force fpi_t)0) /* * Skip free page reporting notification for the (possibly merged) page. * This does not hinder free page reporting from grabbing the page, * reporting it and marking it "reported" - it only skips notifying * the free page reporting infrastructure about a newly freed page. For * example, used when temporarily pulling a page from a freelist and * putting it back unmodified. */ #define FPI_SKIP_REPORT_NOTIFY ((__force fpi_t)BIT(0)) /* * Place the (possibly merged) page to the tail of the freelist. Will ignore * page shuffling (relevant code - e.g., memory onlining - is expected to * shuffle the whole zone). * * Note: No code should rely on this flag for correctness - it's purely * to allow for optimizations when handing back either fresh pages * (memory onlining) or untouched pages (page isolation, free page * reporting). */ #define FPI_TO_TAIL ((__force fpi_t)BIT(1)) /* * Don't poison memory with KASAN (only for the tag-based modes). * During boot, all non-reserved memblock memory is exposed to page_alloc. * Poisoning all that memory lengthens boot time, especially on systems with * large amount of RAM. This flag is used to skip that poisoning. * This is only done for the tag-based KASAN modes, as those are able to * detect memory corruptions with the memory tags assigned by default. * All memory allocated normally after boot gets poisoned as usual. */ #define FPI_SKIP_KASAN_POISON ((__force fpi_t)BIT(2)) /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */ static DEFINE_MUTEX(pcp_batch_high_lock); #define MIN_PERCPU_PAGELIST_FRACTION (8) #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID DEFINE_PER_CPU(int, numa_node); EXPORT_PER_CPU_SYMBOL(numa_node); #endif DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key); #ifdef CONFIG_HAVE_MEMORYLESS_NODES /* * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly. * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined. * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem() * defined in . */ DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */ EXPORT_PER_CPU_SYMBOL(_numa_mem_); #endif /* work_structs for global per-cpu drains */ struct pcpu_drain { struct zone *zone; struct work_struct work; }; static DEFINE_MUTEX(pcpu_drain_mutex); static DEFINE_PER_CPU(struct pcpu_drain, pcpu_drain); #ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY volatile unsigned long latent_entropy __latent_entropy; EXPORT_SYMBOL(latent_entropy); #endif /* * Array of node states. */ nodemask_t node_states[NR_NODE_STATES] __read_mostly = { [N_POSSIBLE] = NODE_MASK_ALL, [N_ONLINE] = { { [0] = 1UL } }, #ifndef CONFIG_NUMA [N_NORMAL_MEMORY] = { { [0] = 1UL } }, #ifdef CONFIG_HIGHMEM [N_HIGH_MEMORY] = { { [0] = 1UL } }, #endif [N_MEMORY] = { { [0] = 1UL } }, [N_CPU] = { { [0] = 1UL } }, #endif /* NUMA */ }; EXPORT_SYMBOL(node_states); atomic_long_t _totalram_pages __read_mostly; EXPORT_SYMBOL(_totalram_pages); unsigned long totalreserve_pages __read_mostly; unsigned long totalcma_pages __read_mostly; int percpu_pagelist_fraction; gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK; DEFINE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, init_on_alloc); EXPORT_SYMBOL(init_on_alloc); DEFINE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_FREE_DEFAULT_ON, init_on_free); EXPORT_SYMBOL(init_on_free); static bool _init_on_alloc_enabled_early __read_mostly = IS_ENABLED(CONFIG_INIT_ON_ALLOC_DEFAULT_ON); static int __init early_init_on_alloc(char *buf) { return kstrtobool(buf, &_init_on_alloc_enabled_early); } early_param("init_on_alloc", early_init_on_alloc); static bool _init_on_free_enabled_early __read_mostly = IS_ENABLED(CONFIG_INIT_ON_FREE_DEFAULT_ON); static int __init early_init_on_free(char *buf) { return kstrtobool(buf, &_init_on_free_enabled_early); } early_param("init_on_free", early_init_on_free); /* * A cached value of the page's pageblock's migratetype, used when the page is * put on a pcplist. Used to avoid the pageblock migratetype lookup when * freeing from pcplists in most cases, at the cost of possibly becoming stale. * Also the migratetype set in the page does not necessarily match the pcplist * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any * other index - this ensures that it will be put on the correct CMA freelist. */ static inline int get_pcppage_migratetype(struct page *page) { return page->index; } static inline void set_pcppage_migratetype(struct page *page, int migratetype) { page->index = migratetype; } #ifdef CONFIG_PM_SLEEP /* * The following functions are used by the suspend/hibernate code to temporarily * change gfp_allowed_mask in order to avoid using I/O during memory allocations * while devices are suspended. To avoid races with the suspend/hibernate code, * they should always be called with system_transition_mutex held * (gfp_allowed_mask also should only be modified with system_transition_mutex * held, unless the suspend/hibernate code is guaranteed not to run in parallel * with that modification). */ static gfp_t saved_gfp_mask; void pm_restore_gfp_mask(void) { WARN_ON(!mutex_is_locked(&system_transition_mutex)); if (saved_gfp_mask) { gfp_allowed_mask = saved_gfp_mask; saved_gfp_mask = 0; } } void pm_restrict_gfp_mask(void) { WARN_ON(!mutex_is_locked(&system_transition_mutex)); WARN_ON(saved_gfp_mask); saved_gfp_mask = gfp_allowed_mask; gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS); } bool pm_suspended_storage(void) { if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS)) return false; return true; } #endif /* CONFIG_PM_SLEEP */ #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE unsigned int pageblock_order __read_mostly; #endif static void __free_pages_ok(struct page *page, unsigned int order, fpi_t fpi_flags); /* * results with 256, 32 in the lowmem_reserve sysctl: * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high) * 1G machine -> (16M dma, 784M normal, 224M high) * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL * HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA * * TBD: should special case ZONE_DMA32 machines here - in those we normally * don't need any ZONE_NORMAL reservation */ int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = { #ifdef CONFIG_ZONE_DMA [ZONE_DMA] = 256, #endif #ifdef CONFIG_ZONE_DMA32 [ZONE_DMA32] = 256, #endif [ZONE_NORMAL] = 32, #ifdef CONFIG_HIGHMEM [ZONE_HIGHMEM] = 0, #endif [ZONE_MOVABLE] = 0, }; static char * const zone_names[MAX_NR_ZONES] = { #ifdef CONFIG_ZONE_DMA "DMA", #endif #ifdef CONFIG_ZONE_DMA32 "DMA32", #endif "Normal", #ifdef CONFIG_HIGHMEM "HighMem", #endif "Movable", #ifdef CONFIG_ZONE_DEVICE "Device", #endif }; const char * const migratetype_names[MIGRATE_TYPES] = { "Unmovable", "Movable", "Reclaimable", "HighAtomic", #ifdef CONFIG_CMA "CMA", #endif #ifdef CONFIG_MEMORY_ISOLATION "Isolate", #endif }; compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = { [NULL_COMPOUND_DTOR] = NULL, [COMPOUND_PAGE_DTOR] = free_compound_page, #ifdef CONFIG_HUGETLB_PAGE [HUGETLB_PAGE_DTOR] = free_huge_page, #endif #ifdef CONFIG_TRANSPARENT_HUGEPAGE [TRANSHUGE_PAGE_DTOR] = free_transhuge_page, #endif }; int min_free_kbytes = 1024; int user_min_free_kbytes = -1; #ifdef CONFIG_DISCONTIGMEM /* * DiscontigMem defines memory ranges as separate pg_data_t even if the ranges * are not on separate NUMA nodes. Functionally this works but with * watermark_boost_factor, it can reclaim prematurely as the ranges can be * quite small. By default, do not boost watermarks on discontigmem as in * many cases very high-order allocations like THP are likely to be * unsupported and the premature reclaim offsets the advantage of long-term * fragmentation avoidance. */ int watermark_boost_factor __read_mostly; #else int watermark_boost_factor __read_mostly = 15000; #endif int watermark_scale_factor = 10; static unsigned long nr_kernel_pages __initdata; static unsigned long nr_all_pages __initdata; static unsigned long dma_reserve __initdata; static unsigned long arch_zone_lowest_possible_pfn[MAX_NR_ZONES] __initdata; static unsigned long arch_zone_highest_possible_pfn[MAX_NR_ZONES] __initdata; static unsigned long required_kernelcore __initdata; static unsigned long required_kernelcore_percent __initdata; static unsigned long required_movablecore __initdata; static unsigned long required_movablecore_percent __initdata; static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata; static bool mirrored_kernelcore __meminitdata; /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */ int movable_zone; EXPORT_SYMBOL(movable_zone); #if MAX_NUMNODES > 1 unsigned int nr_node_ids __read_mostly = MAX_NUMNODES; unsigned int nr_online_nodes __read_mostly = 1; EXPORT_SYMBOL(nr_node_ids); EXPORT_SYMBOL(nr_online_nodes); #endif int page_group_by_mobility_disabled __read_mostly; #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT /* * During boot we initialize deferred pages on-demand, as needed, but once * page_alloc_init_late() has finished, the deferred pages are all initialized, * and we can permanently disable that path. */ static DEFINE_STATIC_KEY_TRUE(deferred_pages); /* * Calling kasan_poison_pages() only after deferred memory initialization * has completed. Poisoning pages during deferred memory init will greatly * lengthen the process and cause problem in large memory systems as the * deferred pages initialization is done with interrupt disabled. * * Assuming that there will be no reference to those newly initialized * pages before they are ever allocated, this should have no effect on * KASAN memory tracking as the poison will be properly inserted at page * allocation time. The only corner case is when pages are allocated by * on-demand allocation and then freed again before the deferred pages * initialization is done, but this is not likely to happen. */ static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags) { return static_branch_unlikely(&deferred_pages) || (!IS_ENABLED(CONFIG_KASAN_GENERIC) && (fpi_flags & FPI_SKIP_KASAN_POISON)) || PageSkipKASanPoison(page); } /* Returns true if the struct page for the pfn is uninitialised */ static inline bool __meminit early_page_uninitialised(unsigned long pfn) { int nid = early_pfn_to_nid(pfn); if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn) return true; return false; } /* * Returns true when the remaining initialisation should be deferred until * later in the boot cycle when it can be parallelised. */ static bool __meminit defer_init(int nid, unsigned long pfn, unsigned long end_pfn) { static unsigned long prev_end_pfn, nr_initialised; /* * prev_end_pfn static that contains the end of previous zone * No need to protect because called very early in boot before smp_init. */ if (prev_end_pfn != end_pfn) { prev_end_pfn = end_pfn; nr_initialised = 0; } /* Always populate low zones for address-constrained allocations */ if (end_pfn < pgdat_end_pfn(NODE_DATA(nid))) return false; if (NODE_DATA(nid)->first_deferred_pfn != ULONG_MAX) return true; /* * We start only with one section of pages, more pages are added as * needed until the rest of deferred pages are initialized. */ nr_initialised++; if ((nr_initialised > PAGES_PER_SECTION) && (pfn & (PAGES_PER_SECTION - 1)) == 0) { NODE_DATA(nid)->first_deferred_pfn = pfn; return true; } return false; } #else static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags) { return (!IS_ENABLED(CONFIG_KASAN_GENERIC) && (fpi_flags & FPI_SKIP_KASAN_POISON)) || PageSkipKASanPoison(page); } static inline bool early_page_uninitialised(unsigned long pfn) { return false; } static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn) { return false; } #endif /* Return a pointer to the bitmap storing bits affecting a block of pages */ static inline unsigned long *get_pageblock_bitmap(struct page *page, unsigned long pfn) { #ifdef CONFIG_SPARSEMEM return section_to_usemap(__pfn_to_section(pfn)); #else return page_zone(page)->pageblock_flags; #endif /* CONFIG_SPARSEMEM */ } static inline int pfn_to_bitidx(struct page *page, unsigned long pfn) { #ifdef CONFIG_SPARSEMEM pfn &= (PAGES_PER_SECTION-1); #else pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages); #endif /* CONFIG_SPARSEMEM */ return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS; } static __always_inline unsigned long __get_pfnblock_flags_mask(struct page *page, unsigned long pfn, unsigned long mask) { unsigned long *bitmap; unsigned long bitidx, word_bitidx; unsigned long word; bitmap = get_pageblock_bitmap(page, pfn); bitidx = pfn_to_bitidx(page, pfn); word_bitidx = bitidx / BITS_PER_LONG; bitidx &= (BITS_PER_LONG-1); word = bitmap[word_bitidx]; return (word >> bitidx) & mask; } /** * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages * @page: The page within the block of interest * @pfn: The target page frame number * @mask: mask of bits that the caller is interested in * * Return: pageblock_bits flags */ unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn, unsigned long mask) { return __get_pfnblock_flags_mask(page, pfn, mask); } static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn) { return __get_pfnblock_flags_mask(page, pfn, MIGRATETYPE_MASK); } /** * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages * @page: The page within the block of interest * @flags: The flags to set * @pfn: The target page frame number * @mask: mask of bits that the caller is interested in */ void set_pfnblock_flags_mask(struct page *page, unsigned long flags, unsigned long pfn, unsigned long mask) { unsigned long *bitmap; unsigned long bitidx, word_bitidx; unsigned long old_word, word; BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4); BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits)); bitmap = get_pageblock_bitmap(page, pfn); bitidx = pfn_to_bitidx(page, pfn); word_bitidx = bitidx / BITS_PER_LONG; bitidx &= (BITS_PER_LONG-1); VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page); mask <<= bitidx; flags <<= bitidx; word = READ_ONCE(bitmap[word_bitidx]); for (;;) { old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags); if (word == old_word) break; word = old_word; } } void set_pageblock_migratetype(struct page *page, int migratetype) { if (unlikely(page_group_by_mobility_disabled && migratetype < MIGRATE_PCPTYPES)) migratetype = MIGRATE_UNMOVABLE; set_pfnblock_flags_mask(page, (unsigned long)migratetype, page_to_pfn(page), MIGRATETYPE_MASK); } #ifdef CONFIG_DEBUG_VM static int page_outside_zone_boundaries(struct zone *zone, struct page *page) { int ret = 0; unsigned seq; unsigned long pfn = page_to_pfn(page); unsigned long sp, start_pfn; do { seq = zone_span_seqbegin(zone); start_pfn = zone->zone_start_pfn; sp = zone->spanned_pages; if (!zone_spans_pfn(zone, pfn)) ret = 1; } while (zone_span_seqretry(zone, seq)); if (ret) pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n", pfn, zone_to_nid(zone), zone->name, start_pfn, start_pfn + sp); return ret; } static int page_is_consistent(struct zone *zone, struct page *page) { if (!pfn_valid_within(page_to_pfn(page))) return 0; if (zone != page_zone(page)) return 0; return 1; } /* * Temporary debugging check for pages not lying within a given zone. */ static int __maybe_unused bad_range(struct zone *zone, struct page *page) { if (page_outside_zone_boundaries(zone, page)) return 1; if (!page_is_consistent(zone, page)) return 1; return 0; } #else static inline int __maybe_unused bad_range(struct zone *zone, struct page *page) { return 0; } #endif static void bad_page(struct page *page, const char *reason) { static unsigned long resume; static unsigned long nr_shown; static unsigned long nr_unshown; /* * Allow a burst of 60 reports, then keep quiet for that minute; * or allow a steady drip of one report per second. */ if (nr_shown == 60) { if (time_before(jiffies, resume)) { nr_unshown++; goto out; } if (nr_unshown) { pr_alert( "BUG: Bad page state: %lu messages suppressed\n", nr_unshown); nr_unshown = 0; } nr_shown = 0; } if (nr_shown++ == 0) resume = jiffies + 60 * HZ; pr_alert("BUG: Bad page state in process %s pfn:%05lx\n", current->comm, page_to_pfn(page)); __dump_page(page, reason); dump_page_owner(page); print_modules(); dump_stack(); out: /* Leave bad fields for debug, except PageBuddy could make trouble */ page_mapcount_reset(page); /* remove PageBuddy */ add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); } /* * Higher-order pages are called "compound pages". They are structured thusly: * * The first PAGE_SIZE page is called the "head page" and have PG_head set. * * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded * in bit 0 of page->compound_head. The rest of bits is pointer to head page. * * The first tail page's ->compound_dtor holds the offset in array of compound * page destructors. See compound_page_dtors. * * The first tail page's ->compound_order holds the order of allocation. * This usage means that zero-order pages may not be compound. */ void free_compound_page(struct page *page) { mem_cgroup_uncharge(page); __free_pages_ok(page, compound_order(page), FPI_NONE); } void prep_compound_page(struct page *page, unsigned int order) { int i; int nr_pages = 1 << order; __SetPageHead(page); for (i = 1; i < nr_pages; i++) { struct page *p = page + i; set_page_count(p, 0); p->mapping = TAIL_MAPPING; set_compound_head(p, page); } set_compound_page_dtor(page, COMPOUND_PAGE_DTOR); set_compound_order(page, order); atomic_set(compound_mapcount_ptr(page), -1); if (hpage_pincount_available(page)) atomic_set(compound_pincount_ptr(page), 0); } #ifdef CONFIG_DEBUG_PAGEALLOC unsigned int _debug_guardpage_minorder; bool _debug_pagealloc_enabled_early __read_mostly = IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT); EXPORT_SYMBOL(_debug_pagealloc_enabled_early); DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled); EXPORT_SYMBOL(_debug_pagealloc_enabled); DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled); static int __init early_debug_pagealloc(char *buf) { return kstrtobool(buf, &_debug_pagealloc_enabled_early); } early_param("debug_pagealloc", early_debug_pagealloc); static int __init debug_guardpage_minorder_setup(char *buf) { unsigned long res; if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) { pr_err("Bad debug_guardpage_minorder value\n"); return 0; } _debug_guardpage_minorder = res; pr_info("Setting debug_guardpage_minorder to %lu\n", res); return 0; } early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup); static inline bool set_page_guard(struct zone *zone, struct page *page, unsigned int order, int migratetype) { if (!debug_guardpage_enabled()) return false; if (order >= debug_guardpage_minorder()) return false; __SetPageGuard(page); INIT_LIST_HEAD(&page->lru); set_page_private(page, order); /* Guard pages are not available for any usage */ __mod_zone_freepage_state(zone, -(1 << order), migratetype); return true; } static inline void clear_page_guard(struct zone *zone, struct page *page, unsigned int order, int migratetype) { if (!debug_guardpage_enabled()) return; __ClearPageGuard(page); set_page_private(page, 0); if (!is_migrate_isolate(migratetype)) __mod_zone_freepage_state(zone, (1 << order), migratetype); } #else static inline bool set_page_guard(struct zone *zone, struct page *page, unsigned int order, int migratetype) { return false; } static inline void clear_page_guard(struct zone *zone, struct page *page, unsigned int order, int migratetype) {} #endif /* * Enable static keys related to various memory debugging and hardening options. * Some override others, and depend on early params that are evaluated in the * order of appearance. So we need to first gather the full picture of what was * enabled, and then make decisions. */ void init_mem_debugging_and_hardening(void) { bool page_poisoning_requested = false; #ifdef CONFIG_PAGE_POISONING /* * Page poisoning is debug page alloc for some arches. If * either of those options are enabled, enable poisoning. */ if (page_poisoning_enabled() || (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) && debug_pagealloc_enabled())) { static_branch_enable(&_page_poisoning_enabled); page_poisoning_requested = true; } #endif if (_init_on_alloc_enabled_early) { if (page_poisoning_requested) pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, " "will take precedence over init_on_alloc\n"); else static_branch_enable(&init_on_alloc); } if (_init_on_free_enabled_early) { if (page_poisoning_requested) pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, " "will take precedence over init_on_free\n"); else static_branch_enable(&init_on_free); } #ifdef CONFIG_DEBUG_PAGEALLOC if (!debug_pagealloc_enabled()) return; static_branch_enable(&_debug_pagealloc_enabled); if (!debug_guardpage_minorder()) return; static_branch_enable(&_debug_guardpage_enabled); #endif } static inline void set_buddy_order(struct page *page, unsigned int order) { set_page_private(page, order); __SetPageBuddy(page); } /* * This function checks whether a page is free && is the buddy * we can coalesce a page and its buddy if * (a) the buddy is not in a hole (check before calling!) && * (b) the buddy is in the buddy system && * (c) a page and its buddy have the same order && * (d) a page and its buddy are in the same zone. * * For recording whether a page is in the buddy system, we set PageBuddy. * Setting, clearing, and testing PageBuddy is serialized by zone->lock. * * For recording page's order, we use page_private(page). */ static inline bool page_is_buddy(struct page *page, struct page *buddy, unsigned int order) { if (!page_is_guard(buddy) && !PageBuddy(buddy)) return false; if (buddy_order(buddy) != order) return false; /* * zone check is done late to avoid uselessly calculating * zone/node ids for pages that could never merge. */ if (page_zone_id(page) != page_zone_id(buddy)) return false; VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); return true; } #ifdef CONFIG_COMPACTION static inline struct capture_control *task_capc(struct zone *zone) { struct capture_control *capc = current->capture_control; return unlikely(capc) && !(current->flags & PF_KTHREAD) && !capc->page && capc->cc->zone == zone ? capc : NULL; } static inline bool compaction_capture(struct capture_control *capc, struct page *page, int order, int migratetype) { if (!capc || order != capc->cc->order) return false; /* Do not accidentally pollute CMA or isolated regions*/ if (is_migrate_cma(migratetype) || is_migrate_isolate(migratetype)) return false; /* * Do not let lower order allocations pollute a movable pageblock. * This might let an unmovable request use a reclaimable pageblock * and vice-versa but no more than normal fallback logic which can * have trouble finding a high-order free page. */ if (order < pageblock_order && migratetype == MIGRATE_MOVABLE) return false; capc->page = page; return true; } #else static inline struct capture_control *task_capc(struct zone *zone) { return NULL; } static inline bool compaction_capture(struct capture_control *capc, struct page *page, int order, int migratetype) { return false; } #endif /* CONFIG_COMPACTION */ /* Used for pages not on another list */ static inline void add_to_free_list(struct page *page, struct zone *zone, unsigned int order, int migratetype) { struct free_area *area = &zone->free_area[order]; list_add(&page->lru, &area->free_list[migratetype]); area->nr_free++; } /* Used for pages not on another list */ static inline void add_to_free_list_tail(struct page *page, struct zone *zone, unsigned int order, int migratetype) { struct free_area *area = &zone->free_area[order]; list_add_tail(&page->lru, &area->free_list[migratetype]); area->nr_free++; } /* * Used for pages which are on another list. Move the pages to the tail * of the list - so the moved pages won't immediately be considered for * allocation again (e.g., optimization for memory onlining). */ static inline void move_to_free_list(struct page *page, struct zone *zone, unsigned int order, int migratetype) { struct free_area *area = &zone->free_area[order]; list_move_tail(&page->lru, &area->free_list[migratetype]); } static inline void del_page_from_free_list(struct page *page, struct zone *zone, unsigned int order) { /* clear reported state and update reported page count */ if (page_reported(page)) __ClearPageReported(page); list_del(&page->lru); __ClearPageBuddy(page); set_page_private(page, 0); zone->free_area[order].nr_free--; } /* * If this is not the largest possible page, check if the buddy * of the next-highest order is free. If it is, it's possible * that pages are being freed that will coalesce soon. In case, * that is happening, add the free page to the tail of the list * so it's less likely to be used soon and more likely to be merged * as a higher order page */ static inline bool buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn, struct page *page, unsigned int order) { struct page *higher_page, *higher_buddy; unsigned long combined_pfn; if (order >= MAX_ORDER - 2) return false; if (!pfn_valid_within(buddy_pfn)) return false; combined_pfn = buddy_pfn & pfn; higher_page = page + (combined_pfn - pfn); buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1); higher_buddy = higher_page + (buddy_pfn - combined_pfn); return pfn_valid_within(buddy_pfn) && page_is_buddy(higher_page, higher_buddy, order + 1); } /* * Freeing function for a buddy system allocator. * * The concept of a buddy system is to maintain direct-mapped table * (containing bit values) for memory blocks of various "orders". * The bottom level table contains the map for the smallest allocatable * units of memory (here, pages), and each level above it describes * pairs of units from the levels below, hence, "buddies". * At a high level, all that happens here is marking the table entry * at the bottom level available, and propagating the changes upward * as necessary, plus some accounting needed to play nicely with other * parts of the VM system. * At each level, we keep a list of pages, which are heads of continuous * free pages of length of (1 << order) and marked with PageBuddy. * Page's order is recorded in page_private(page) field. * So when we are allocating or freeing one, we can derive the state of the * other. That is, if we allocate a small block, and both were * free, the remainder of the region must be split into blocks. * If a block is freed, and its buddy is also free, then this * triggers coalescing into a block of larger size. * * -- nyc */ static inline void __free_one_page(struct page *page, unsigned long pfn, struct zone *zone, unsigned int order, int migratetype, fpi_t fpi_flags) { struct capture_control *capc = task_capc(zone); unsigned long buddy_pfn; unsigned long combined_pfn; unsigned int max_order; struct page *buddy; bool to_tail; max_order = min_t(unsigned int, MAX_ORDER - 1, pageblock_order); VM_BUG_ON(!zone_is_initialized(zone)); VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page); VM_BUG_ON(migratetype == -1); if (likely(!is_migrate_isolate(migratetype))) __mod_zone_freepage_state(zone, 1 << order, migratetype); VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page); VM_BUG_ON_PAGE(bad_range(zone, page), page); continue_merging: while (order < max_order) { if (compaction_capture(capc, page, order, migratetype)) { __mod_zone_freepage_state(zone, -(1 << order), migratetype); return; } buddy_pfn = __find_buddy_pfn(pfn, order); buddy = page + (buddy_pfn - pfn); if (!pfn_valid_within(buddy_pfn)) goto done_merging; if (!page_is_buddy(page, buddy, order)) goto done_merging; /* * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page, * merge with it and move up one order. */ if (page_is_guard(buddy)) clear_page_guard(zone, buddy, order, migratetype); else del_page_from_free_list(buddy, zone, order); combined_pfn = buddy_pfn & pfn; page = page + (combined_pfn - pfn); pfn = combined_pfn; order++; } if (order < MAX_ORDER - 1) { /* If we are here, it means order is >= pageblock_order. * We want to prevent merge between freepages on isolate * pageblock and normal pageblock. Without this, pageblock * isolation could cause incorrect freepage or CMA accounting. * * We don't want to hit this code for the more frequent * low-order merging. */ if (unlikely(has_isolate_pageblock(zone))) { int buddy_mt; buddy_pfn = __find_buddy_pfn(pfn, order); buddy = page + (buddy_pfn - pfn); buddy_mt = get_pageblock_migratetype(buddy); if (migratetype != buddy_mt && (is_migrate_isolate(migratetype) || is_migrate_isolate(buddy_mt))) goto done_merging; } max_order = order + 1; goto continue_merging; } done_merging: set_buddy_order(page, order); if (fpi_flags & FPI_TO_TAIL) to_tail = true; else if (is_shuffle_order(order)) to_tail = shuffle_pick_tail(); else to_tail = buddy_merge_likely(pfn, buddy_pfn, page, order); if (to_tail) add_to_free_list_tail(page, zone, order, migratetype); else add_to_free_list(page, zone, order, migratetype); /* Notify page reporting subsystem of freed page */ if (!(fpi_flags & FPI_SKIP_REPORT_NOTIFY)) page_reporting_notify_free(order); } /* * A bad page could be due to a number of fields. Instead of multiple branches, * try and check multiple fields with one check. The caller must do a detailed * check if necessary. */ static inline bool page_expected_state(struct page *page, unsigned long check_flags) { if (unlikely(atomic_read(&page->_mapcount) != -1)) return false; if (unlikely((unsigned long)page->mapping | page_ref_count(page) | #ifdef CONFIG_MEMCG page->memcg_data | #endif (page->flags & check_flags))) return false; return true; } static const char *page_bad_reason(struct page *page, unsigned long flags) { const char *bad_reason = NULL; if (unlikely(atomic_read(&page->_mapcount) != -1)) bad_reason = "nonzero mapcount"; if (unlikely(page->mapping != NULL)) bad_reason = "non-NULL mapping"; if (unlikely(page_ref_count(page) != 0)) bad_reason = "nonzero _refcount"; if (unlikely(page->flags & flags)) { if (flags == PAGE_FLAGS_CHECK_AT_PREP) bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag(s) set"; else bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set"; } #ifdef CONFIG_MEMCG if (unlikely(page->memcg_data)) bad_reason = "page still charged to cgroup"; #endif return bad_reason; } static void check_free_page_bad(struct page *page) { bad_page(page, page_bad_reason(page, PAGE_FLAGS_CHECK_AT_FREE)); } static inline int check_free_page(struct page *page) { if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE))) return 0; /* Something has gone sideways, find it */ check_free_page_bad(page); return 1; } static int free_tail_pages_check(struct page *head_page, struct page *page) { int ret = 1; /* * We rely page->lru.next never has bit 0 set, unless the page * is PageTail(). Let's make sure that's true even for poisoned ->lru. */ BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1); if (!IS_ENABLED(CONFIG_DEBUG_VM)) { ret = 0; goto out; } switch (page - head_page) { case 1: /* the first tail page: ->mapping may be compound_mapcount() */ if (unlikely(compound_mapcount(page))) { bad_page(page, "nonzero compound_mapcount"); goto out; } break; case 2: /* * the second tail page: ->mapping is * deferred_list.next -- ignore value. */ break; default: if (page->mapping != TAIL_MAPPING) { bad_page(page, "corrupted mapping in tail page"); goto out; } break; } if (unlikely(!PageTail(page))) { bad_page(page, "PageTail not set"); goto out; } if (unlikely(compound_head(page) != head_page)) { bad_page(page, "compound_head not consistent"); goto out; } ret = 0; out: page->mapping = NULL; clear_compound_head(page); return ret; } static void kernel_init_free_pages(struct page *page, int numpages, bool zero_tags) { int i; if (zero_tags) { for (i = 0; i < numpages; i++) tag_clear_highpage(page + i); return; } /* s390's use of memset() could override KASAN redzones. */ kasan_disable_current(); for (i = 0; i < numpages; i++) { u8 tag = page_kasan_tag(page + i); page_kasan_tag_reset(page + i); clear_highpage(page + i); page_kasan_tag_set(page + i, tag); } kasan_enable_current(); } static __always_inline bool free_pages_prepare(struct page *page, unsigned int order, bool check_free, fpi_t fpi_flags) { int bad = 0; bool skip_kasan_poison = should_skip_kasan_poison(page, fpi_flags); VM_BUG_ON_PAGE(PageTail(page), page); trace_mm_page_free(page, order); if (unlikely(PageHWPoison(page)) && !order) { /* * Do not let hwpoison pages hit pcplists/buddy * Untie memcg state and reset page's owner */ if (memcg_kmem_enabled() && PageMemcgKmem(page)) __memcg_kmem_uncharge_page(page, order); reset_page_owner(page, order); return false; } /* * Check tail pages before head page information is cleared to * avoid checking PageCompound for order-0 pages. */ if (unlikely(order)) { bool compound = PageCompound(page); int i; VM_BUG_ON_PAGE(compound && compound_order(page) != order, page); if (compound) ClearPageDoubleMap(page); for (i = 1; i < (1 << order); i++) { if (compound) bad += free_tail_pages_check(page, page + i); if (unlikely(check_free_page(page + i))) { bad++; continue; } (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; } } if (PageMappingFlags(page)) page->mapping = NULL; if (memcg_kmem_enabled() && PageMemcgKmem(page)) __memcg_kmem_uncharge_page(page, order); if (check_free) bad += check_free_page(page); if (bad) return false; page_cpupid_reset_last(page); page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; reset_page_owner(page, order); if (!PageHighMem(page)) { debug_check_no_locks_freed(page_address(page), PAGE_SIZE << order); debug_check_no_obj_freed(page_address(page), PAGE_SIZE << order); } kernel_poison_pages(page, 1 << order); /* * As memory initialization might be integrated into KASAN, * kasan_free_pages and kernel_init_free_pages must be * kept together to avoid discrepancies in behavior. * * With hardware tag-based KASAN, memory tags must be set before the * page becomes unavailable via debug_pagealloc or arch_free_page. */ if (kasan_has_integrated_init()) { if (!skip_kasan_poison) kasan_free_pages(page, order); } else { bool init = want_init_on_free(); if (init) kernel_init_free_pages(page, 1 << order, false); if (!skip_kasan_poison) kasan_poison_pages(page, order, init); } /* * arch_free_page() can make the page's contents inaccessible. s390 * does this. So nothing which can access the page's contents should * happen after this. */ arch_free_page(page, order); debug_pagealloc_unmap_pages(page, 1 << order); return true; } #ifdef CONFIG_DEBUG_VM /* * With DEBUG_VM enabled, order-0 pages are checked immediately when being freed * to pcp lists. With debug_pagealloc also enabled, they are also rechecked when * moved from pcp lists to free lists. */ static bool free_pcp_prepare(struct page *page) { return free_pages_prepare(page, 0, true, FPI_NONE); } static bool bulkfree_pcp_prepare(struct page *page) { if (debug_pagealloc_enabled_static()) return check_free_page(page); else return false; } #else /* * With DEBUG_VM disabled, order-0 pages being freed are checked only when * moving from pcp lists to free list in order to reduce overhead. With * debug_pagealloc enabled, they are checked also immediately when being freed * to the pcp lists. */ static bool free_pcp_prepare(struct page *page) { if (debug_pagealloc_enabled_static()) return free_pages_prepare(page, 0, true, FPI_NONE); else return free_pages_prepare(page, 0, false, FPI_NONE); } static bool bulkfree_pcp_prepare(struct page *page) { return check_free_page(page); } #endif /* CONFIG_DEBUG_VM */ static inline void prefetch_buddy(struct page *page) { unsigned long pfn = page_to_pfn(page); unsigned long buddy_pfn = __find_buddy_pfn(pfn, 0); struct page *buddy = page + (buddy_pfn - pfn); prefetch(buddy); } /* * Frees a number of pages from the PCP lists * Assumes all pages on list are in same zone, and of same order. * count is the number of pages to free. * * If the zone was previously in an "all pages pinned" state then look to * see if this freeing clears that state. * * And clear the zone's pages_scanned counter, to hold off the "all pages are * pinned" detection logic. */ static void free_pcppages_bulk(struct zone *zone, int count, struct per_cpu_pages *pcp) { int migratetype = 0; int batch_free = 0; int prefetch_nr = READ_ONCE(pcp->batch); bool isolated_pageblocks; struct page *page, *tmp; LIST_HEAD(head); /* * Ensure proper count is passed which otherwise would stuck in the * below while (list_empty(list)) loop. */ count = min(pcp->count, count); while (count) { struct list_head *list; /* * Remove pages from lists in a round-robin fashion. A * batch_free count is maintained that is incremented when an * empty list is encountered. This is so more pages are freed * off fuller lists instead of spinning excessively around empty * lists */ do { batch_free++; if (++migratetype == MIGRATE_PCPTYPES) migratetype = 0; list = &pcp->lists[migratetype]; } while (list_empty(list)); /* This is the only non-empty list. Free them all. */ if (batch_free == MIGRATE_PCPTYPES) batch_free = count; do { page = list_last_entry(list, struct page, lru); /* must delete to avoid corrupting pcp list */ list_del(&page->lru); pcp->count--; if (bulkfree_pcp_prepare(page)) continue; list_add_tail(&page->lru, &head); /* * We are going to put the page back to the global * pool, prefetch its buddy to speed up later access * under zone->lock. It is believed the overhead of * an additional test and calculating buddy_pfn here * can be offset by reduced memory latency later. To * avoid excessive prefetching due to large count, only * prefetch buddy for the first pcp->batch nr of pages. */ if (prefetch_nr) { prefetch_buddy(page); prefetch_nr--; } } while (--count && --batch_free && !list_empty(list)); } spin_lock(&zone->lock); isolated_pageblocks = has_isolate_pageblock(zone); /* * Use safe version since after __free_one_page(), * page->lru.next will not point to original list. */ list_for_each_entry_safe(page, tmp, &head, lru) { int mt = get_pcppage_migratetype(page); /* MIGRATE_ISOLATE page should not go to pcplists */ VM_BUG_ON_PAGE(is_migrate_isolate(mt), page); /* Pageblock could have been isolated meanwhile */ if (unlikely(isolated_pageblocks)) mt = get_pageblock_migratetype(page); __free_one_page(page, page_to_pfn(page), zone, 0, mt, FPI_NONE); trace_mm_page_pcpu_drain(page, 0, mt); } spin_unlock(&zone->lock); } static void free_one_page(struct zone *zone, struct page *page, unsigned long pfn, unsigned int order, int migratetype, fpi_t fpi_flags) { spin_lock(&zone->lock); if (unlikely(has_isolate_pageblock(zone) || is_migrate_isolate(migratetype))) { migratetype = get_pfnblock_migratetype(page, pfn); } __free_one_page(page, pfn, zone, order, migratetype, fpi_flags); spin_unlock(&zone->lock); } static void __meminit __init_single_page(struct page *page, unsigned long pfn, unsigned long zone, int nid) { mm_zero_struct_page(page); set_page_links(page, zone, nid, pfn); init_page_count(page); page_mapcount_reset(page); page_cpupid_reset_last(page); page_kasan_tag_reset(page); INIT_LIST_HEAD(&page->lru); #ifdef WANT_PAGE_VIRTUAL /* The shift won't overflow because ZONE_NORMAL is below 4G. */ if (!is_highmem_idx(zone)) set_page_address(page, __va(pfn << PAGE_SHIFT)); #endif } #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT static void __meminit init_reserved_page(unsigned long pfn) { pg_data_t *pgdat; int nid, zid; if (!early_page_uninitialised(pfn)) return; nid = early_pfn_to_nid(pfn); pgdat = NODE_DATA(nid); for (zid = 0; zid < MAX_NR_ZONES; zid++) { struct zone *zone = &pgdat->node_zones[zid]; if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone)) break; } __init_single_page(pfn_to_page(pfn), pfn, zid, nid); } #else static inline void init_reserved_page(unsigned long pfn) { } #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ /* * Initialised pages do not have PageReserved set. This function is * called for each range allocated by the bootmem allocator and * marks the pages PageReserved. The remaining valid pages are later * sent to the buddy page allocator. */ void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end) { unsigned long start_pfn = PFN_DOWN(start); unsigned long end_pfn = PFN_UP(end); for (; start_pfn < end_pfn; start_pfn++) { if (pfn_valid(start_pfn)) { struct page *page = pfn_to_page(start_pfn); init_reserved_page(start_pfn); /* Avoid false-positive PageTail() */ INIT_LIST_HEAD(&page->lru); /* * no need for atomic set_bit because the struct * page is not visible yet so nobody should * access it yet. */ __SetPageReserved(page); } } } static void __free_pages_ok(struct page *page, unsigned int order, fpi_t fpi_flags) { unsigned long flags; int migratetype; unsigned long pfn = page_to_pfn(page); if (!free_pages_prepare(page, order, true, fpi_flags)) return; migratetype = get_pfnblock_migratetype(page, pfn); local_irq_save(flags); __count_vm_events(PGFREE, 1 << order); free_one_page(page_zone(page), page, pfn, order, migratetype, fpi_flags); local_irq_restore(flags); } void __free_pages_core(struct page *page, unsigned int order) { unsigned int nr_pages = 1 << order; struct page *p = page; unsigned int loop; /* * When initializing the memmap, __init_single_page() sets the refcount * of all pages to 1 ("allocated"/"not free"). We have to set the * refcount of all involved pages to 0. */ prefetchw(p); for (loop = 0; loop < (nr_pages - 1); loop++, p++) { prefetchw(p + 1); __ClearPageReserved(p); set_page_count(p, 0); } __ClearPageReserved(p); set_page_count(p, 0); atomic_long_add(nr_pages, &page_zone(page)->managed_pages); /* * Bypass PCP and place fresh pages right to the tail, primarily * relevant for memory onlining. */ __free_pages_ok(page, order, FPI_TO_TAIL | FPI_SKIP_KASAN_POISON); } #ifdef CONFIG_NEED_MULTIPLE_NODES /* * During memory init memblocks map pfns to nids. The search is expensive and * this caches recent lookups. The implementation of __early_pfn_to_nid * treats start/end as pfns. */ struct mminit_pfnnid_cache { unsigned long last_start; unsigned long last_end; int last_nid; }; static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata; /* * Required by SPARSEMEM. Given a PFN, return what node the PFN is on. */ static int __meminit __early_pfn_to_nid(unsigned long pfn, struct mminit_pfnnid_cache *state) { unsigned long start_pfn, end_pfn; int nid; if (state->last_start <= pfn && pfn < state->last_end) return state->last_nid; nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn); if (nid != NUMA_NO_NODE) { state->last_start = start_pfn; state->last_end = end_pfn; state->last_nid = nid; } return nid; } int __meminit early_pfn_to_nid(unsigned long pfn) { static DEFINE_SPINLOCK(early_pfn_lock); int nid; spin_lock(&early_pfn_lock); nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache); if (nid < 0) nid = first_online_node; spin_unlock(&early_pfn_lock); return nid; } #endif /* CONFIG_NEED_MULTIPLE_NODES */ void __init memblock_free_pages(struct page *page, unsigned long pfn, unsigned int order) { if (early_page_uninitialised(pfn)) return; __free_pages_core(page, order); } /* * Check that the whole (or subset of) a pageblock given by the interval of * [start_pfn, end_pfn) is valid and within the same zone, before scanning it * with the migration of free compaction scanner. The scanners then need to * use only pfn_valid_within() check for arches that allow holes within * pageblocks. * * Return struct page pointer of start_pfn, or NULL if checks were not passed. * * It's possible on some configurations to have a setup like node0 node1 node0 * i.e. it's possible that all pages within a zones range of pages do not * belong to a single zone. We assume that a border between node0 and node1 * can occur within a single pageblock, but not a node0 node1 node0 * interleaving within a single pageblock. It is therefore sufficient to check * the first and last page of a pageblock and avoid checking each individual * page in a pageblock. */ struct page *__pageblock_pfn_to_page(unsigned long start_pfn, unsigned long end_pfn, struct zone *zone) { struct page *start_page; struct page *end_page; /* end_pfn is one past the range we are checking */ end_pfn--; if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn)) return NULL; start_page = pfn_to_online_page(start_pfn); if (!start_page) return NULL; if (page_zone(start_page) != zone) return NULL; end_page = pfn_to_page(end_pfn); /* This gives a shorter code than deriving page_zone(end_page) */ if (page_zone_id(start_page) != page_zone_id(end_page)) return NULL; return start_page; } void set_zone_contiguous(struct zone *zone) { unsigned long block_start_pfn = zone->zone_start_pfn; unsigned long block_end_pfn; block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages); for (; block_start_pfn < zone_end_pfn(zone); block_start_pfn = block_end_pfn, block_end_pfn += pageblock_nr_pages) { block_end_pfn = min(block_end_pfn, zone_end_pfn(zone)); if (!__pageblock_pfn_to_page(block_start_pfn, block_end_pfn, zone)) return; cond_resched(); } /* We confirm that there is no hole */ zone->contiguous = true; } void clear_zone_contiguous(struct zone *zone) { zone->contiguous = false; } #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT static void __init deferred_free_range(unsigned long pfn, unsigned long nr_pages) { struct page *page; unsigned long i; if (!nr_pages) return; page = pfn_to_page(pfn); /* Free a large naturally-aligned chunk if possible */ if (nr_pages == pageblock_nr_pages && (pfn & (pageblock_nr_pages - 1)) == 0) { set_pageblock_migratetype(page, MIGRATE_MOVABLE); __free_pages_core(page, pageblock_order); return; } for (i = 0; i < nr_pages; i++, page++, pfn++) { if ((pfn & (pageblock_nr_pages - 1)) == 0) set_pageblock_migratetype(page, MIGRATE_MOVABLE); __free_pages_core(page, 0); } } /* Completion tracking for deferred_init_memmap() threads */ static atomic_t pgdat_init_n_undone __initdata; static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp); static inline void __init pgdat_init_report_one_done(void) { if (atomic_dec_and_test(&pgdat_init_n_undone)) complete(&pgdat_init_all_done_comp); } /* * Returns true if page needs to be initialized or freed to buddy allocator. * * First we check if pfn is valid on architectures where it is possible to have * holes within pageblock_nr_pages. On systems where it is not possible, this * function is optimized out. * * Then, we check if a current large page is valid by only checking the validity * of the head pfn. */ static inline bool __init deferred_pfn_valid(unsigned long pfn) { if (!pfn_valid_within(pfn)) return false; if (!(pfn & (pageblock_nr_pages - 1)) && !pfn_valid(pfn)) return false; return true; } /* * Free pages to buddy allocator. Try to free aligned pages in * pageblock_nr_pages sizes. */ static void __init deferred_free_pages(unsigned long pfn, unsigned long end_pfn) { unsigned long nr_pgmask = pageblock_nr_pages - 1; unsigned long nr_free = 0; for (; pfn < end_pfn; pfn++) { if (!deferred_pfn_valid(pfn)) { deferred_free_range(pfn - nr_free, nr_free); nr_free = 0; } else if (!(pfn & nr_pgmask)) { deferred_free_range(pfn - nr_free, nr_free); nr_free = 1; } else { nr_free++; } } /* Free the last block of pages to allocator */ deferred_free_range(pfn - nr_free, nr_free); } /* * Initialize struct pages. We minimize pfn page lookups and scheduler checks * by performing it only once every pageblock_nr_pages. * Return number of pages initialized. */ static unsigned long __init deferred_init_pages(struct zone *zone, unsigned long pfn, unsigned long end_pfn) { unsigned long nr_pgmask = pageblock_nr_pages - 1; int nid = zone_to_nid(zone); unsigned long nr_pages = 0; int zid = zone_idx(zone); struct page *page = NULL; for (; pfn < end_pfn; pfn++) { if (!deferred_pfn_valid(pfn)) { page = NULL; continue; } else if (!page || !(pfn & nr_pgmask)) { page = pfn_to_page(pfn); } else { page++; } __init_single_page(page, pfn, zid, nid); nr_pages++; } return (nr_pages); } /* * This function is meant to pre-load the iterator for the zone init. * Specifically it walks through the ranges until we are caught up to the * first_init_pfn value and exits there. If we never encounter the value we * return false indicating there are no valid ranges left. */ static bool __init deferred_init_mem_pfn_range_in_zone(u64 *i, struct zone *zone, unsigned long *spfn, unsigned long *epfn, unsigned long first_init_pfn) { u64 j; /* * Start out by walking through the ranges in this zone that have * already been initialized. We don't need to do anything with them * so we just need to flush them out of the system. */ for_each_free_mem_pfn_range_in_zone(j, zone, spfn, epfn) { if (*epfn <= first_init_pfn) continue; if (*spfn < first_init_pfn) *spfn = first_init_pfn; *i = j; return true; } return false; } /* * Initialize and free pages. We do it in two loops: first we initialize * struct page, then free to buddy allocator, because while we are * freeing pages we can access pages that are ahead (computing buddy * page in __free_one_page()). * * In order to try and keep some memory in the cache we have the loop * broken along max page order boundaries. This way we will not cause * any issues with the buddy page computation. */ static unsigned long __init deferred_init_maxorder(u64 *i, struct zone *zone, unsigned long *start_pfn, unsigned long *end_pfn) { unsigned long mo_pfn = ALIGN(*start_pfn + 1, MAX_ORDER_NR_PAGES); unsigned long spfn = *start_pfn, epfn = *end_pfn; unsigned long nr_pages = 0; u64 j = *i; /* First we loop through and initialize the page values */ for_each_free_mem_pfn_range_in_zone_from(j, zone, start_pfn, end_pfn) { unsigned long t; if (mo_pfn <= *start_pfn) break; t = min(mo_pfn, *end_pfn); nr_pages += deferred_init_pages(zone, *start_pfn, t); if (mo_pfn < *end_pfn) { *start_pfn = mo_pfn; break; } } /* Reset values and now loop through freeing pages as needed */ swap(j, *i); for_each_free_mem_pfn_range_in_zone_from(j, zone, &spfn, &epfn) { unsigned long t; if (mo_pfn <= spfn) break; t = min(mo_pfn, epfn); deferred_free_pages(spfn, t); if (mo_pfn <= epfn) break; } return nr_pages; } static void __init deferred_init_memmap_chunk(unsigned long start_pfn, unsigned long end_pfn, void *arg) { unsigned long spfn, epfn; struct zone *zone = arg; u64 i; deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, start_pfn); /* * Initialize and free pages in MAX_ORDER sized increments so that we * can avoid introducing any issues with the buddy allocator. */ while (spfn < end_pfn) { deferred_init_maxorder(&i, zone, &spfn, &epfn); cond_resched(); } } /* An arch may override for more concurrency. */ __weak int __init deferred_page_init_max_threads(const struct cpumask *node_cpumask) { return 1; } /* Initialise remaining memory on a node */ static int __init deferred_init_memmap(void *data) { pg_data_t *pgdat = data; const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); unsigned long spfn = 0, epfn = 0; unsigned long first_init_pfn, flags; unsigned long start = jiffies; struct zone *zone; int zid, max_threads; u64 i; /* Bind memory initialisation thread to a local node if possible */ if (!cpumask_empty(cpumask)) set_cpus_allowed_ptr(current, cpumask); pgdat_resize_lock(pgdat, &flags); first_init_pfn = pgdat->first_deferred_pfn; if (first_init_pfn == ULONG_MAX) { pgdat_resize_unlock(pgdat, &flags); pgdat_init_report_one_done(); return 0; } /* Sanity check boundaries */ BUG_ON(pgdat->first_deferred_pfn < pgdat->node_start_pfn); BUG_ON(pgdat->first_deferred_pfn > pgdat_end_pfn(pgdat)); pgdat->first_deferred_pfn = ULONG_MAX; /* * Once we unlock here, the zone cannot be grown anymore, thus if an * interrupt thread must allocate this early in boot, zone must be * pre-grown prior to start of deferred page initialization. */ pgdat_resize_unlock(pgdat, &flags); /* Only the highest zone is deferred so find it */ for (zid = 0; zid < MAX_NR_ZONES; zid++) { zone = pgdat->node_zones + zid; if (first_init_pfn < zone_end_pfn(zone)) break; } /* If the zone is empty somebody else may have cleared out the zone */ if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, first_init_pfn)) goto zone_empty; max_threads = deferred_page_init_max_threads(cpumask); while (spfn < epfn) { unsigned long epfn_align = ALIGN(epfn, PAGES_PER_SECTION); struct padata_mt_job job = { .thread_fn = deferred_init_memmap_chunk, .fn_arg = zone, .start = spfn, .size = epfn_align - spfn, .align = PAGES_PER_SECTION, .min_chunk = PAGES_PER_SECTION, .max_threads = max_threads, }; padata_do_multithreaded(&job); deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, epfn_align); } zone_empty: /* Sanity check that the next zone really is unpopulated */ WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone)); pr_info("node %d deferred pages initialised in %ums\n", pgdat->node_id, jiffies_to_msecs(jiffies - start)); pgdat_init_report_one_done(); return 0; } /* * If this zone has deferred pages, try to grow it by initializing enough * deferred pages to satisfy the allocation specified by order, rounded up to * the nearest PAGES_PER_SECTION boundary. So we're adding memory in increments * of SECTION_SIZE bytes by initializing struct pages in increments of * PAGES_PER_SECTION * sizeof(struct page) bytes. * * Return true when zone was grown, otherwise return false. We return true even * when we grow less than requested, to let the caller decide if there are * enough pages to satisfy the allocation. * * Note: We use noinline because this function is needed only during boot, and * it is called from a __ref function _deferred_grow_zone. This way we are * making sure that it is not inlined into permanent text section. */ static noinline bool __init deferred_grow_zone(struct zone *zone, unsigned int order) { unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION); pg_data_t *pgdat = zone->zone_pgdat; unsigned long first_deferred_pfn = pgdat->first_deferred_pfn; unsigned long spfn, epfn, flags; unsigned long nr_pages = 0; u64 i; /* Only the last zone may have deferred pages */ if (zone_end_pfn(zone) != pgdat_end_pfn(pgdat)) return false; pgdat_resize_lock(pgdat, &flags); /* * If someone grew this zone while we were waiting for spinlock, return * true, as there might be enough pages already. */ if (first_deferred_pfn != pgdat->first_deferred_pfn) { pgdat_resize_unlock(pgdat, &flags); return true; } /* If the zone is empty somebody else may have cleared out the zone */ if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, first_deferred_pfn)) { pgdat->first_deferred_pfn = ULONG_MAX; pgdat_resize_unlock(pgdat, &flags); /* Retry only once. */ return first_deferred_pfn != ULONG_MAX; } /* * Initialize and free pages in MAX_ORDER sized increments so * that we can avoid introducing any issues with the buddy * allocator. */ while (spfn < epfn) { /* update our first deferred PFN for this section */ first_deferred_pfn = spfn; nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn); touch_nmi_watchdog(); /* We should only stop along section boundaries */ if ((first_deferred_pfn ^ spfn) < PAGES_PER_SECTION) continue; /* If our quota has been met we can stop here */ if (nr_pages >= nr_pages_needed) break; } pgdat->first_deferred_pfn = spfn; pgdat_resize_unlock(pgdat, &flags); return nr_pages > 0; } /* * deferred_grow_zone() is __init, but it is called from * get_page_from_freelist() during early boot until deferred_pages permanently * disables this call. This is why we have refdata wrapper to avoid warning, * and to ensure that the function body gets unloaded. */ static bool __ref _deferred_grow_zone(struct zone *zone, unsigned int order) { return deferred_grow_zone(zone, order); } #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ void __init page_alloc_init_late(void) { struct zone *zone; int nid; #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT /* There will be num_node_state(N_MEMORY) threads */ atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY)); for_each_node_state(nid, N_MEMORY) { kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid); } /* Block until all are initialised */ wait_for_completion(&pgdat_init_all_done_comp); /* * The number of managed pages has changed due to the initialisation * so the pcpu batch and high limits needs to be updated or the limits * will be artificially small. */ for_each_populated_zone(zone) zone_pcp_update(zone); /* * We initialized the rest of the deferred pages. Permanently disable * on-demand struct page initialization. */ static_branch_disable(&deferred_pages); /* Reinit limits that are based on free pages after the kernel is up */ files_maxfiles_init(); #endif buffer_init(); /* Discard memblock private memory */ memblock_discard(); for_each_node_state(nid, N_MEMORY) shuffle_free_memory(NODE_DATA(nid)); for_each_populated_zone(zone) set_zone_contiguous(zone); } #ifdef CONFIG_CMA /* Free whole pageblock and set its migration type to MIGRATE_CMA. */ void __init init_cma_reserved_pageblock(struct page *page) { unsigned i = pageblock_nr_pages; struct page *p = page; do { __ClearPageReserved(p); set_page_count(p, 0); } while (++p, --i); set_pageblock_migratetype(page, MIGRATE_CMA); if (pageblock_order >= MAX_ORDER) { i = pageblock_nr_pages; p = page; do { set_page_refcounted(p); __free_pages(p, MAX_ORDER - 1); p += MAX_ORDER_NR_PAGES; } while (i -= MAX_ORDER_NR_PAGES); } else { set_page_refcounted(page); __free_pages(page, pageblock_order); } adjust_managed_page_count(page, pageblock_nr_pages); page_zone(page)->cma_pages += pageblock_nr_pages; } #endif /* * The order of subdivision here is critical for the IO subsystem. * Please do not alter this order without good reasons and regression * testing. Specifically, as large blocks of memory are subdivided, * the order in which smaller blocks are delivered depends on the order * they're subdivided in this function. This is the primary factor * influencing the order in which pages are delivered to the IO * subsystem according to empirical testing, and this is also justified * by considering the behavior of a buddy system containing a single * large block of memory acted on by a series of small allocations. * This behavior is a critical factor in sglist merging's success. * * -- nyc */ static inline void expand(struct zone *zone, struct page *page, int low, int high, int migratetype) { unsigned long size = 1 << high; while (high > low) { high--; size >>= 1; VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]); /* * Mark as guard pages (or page), that will allow to * merge back to allocator when buddy will be freed. * Corresponding page table entries will not be touched, * pages will stay not present in virtual address space */ if (set_page_guard(zone, &page[size], high, migratetype)) continue; add_to_free_list(&page[size], zone, high, migratetype); set_buddy_order(&page[size], high); } } static void check_new_page_bad(struct page *page) { if (unlikely(page->flags & __PG_HWPOISON)) { /* Don't complain about hwpoisoned pages */ page_mapcount_reset(page); /* remove PageBuddy */ return; } bad_page(page, page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP)); } /* * This page is about to be returned from the page allocator */ static inline int check_new_page(struct page *page) { if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON))) return 0; check_new_page_bad(page); return 1; } #ifdef CONFIG_DEBUG_VM /* * With DEBUG_VM enabled, order-0 pages are checked for expected state when * being allocated from pcp lists. With debug_pagealloc also enabled, they are * also checked when pcp lists are refilled from the free lists. */ static inline bool check_pcp_refill(struct page *page) { if (debug_pagealloc_enabled_static()) return check_new_page(page); else return false; } static inline bool check_new_pcp(struct page *page) { return check_new_page(page); } #else /* * With DEBUG_VM disabled, free order-0 pages are checked for expected state * when pcp lists are being refilled from the free lists. With debug_pagealloc * enabled, they are also checked when being allocated from the pcp lists. */ static inline bool check_pcp_refill(struct page *page) { return check_new_page(page); } static inline bool check_new_pcp(struct page *page) { if (debug_pagealloc_enabled_static()) return check_new_page(page); else return false; } #endif /* CONFIG_DEBUG_VM */ static bool check_new_pages(struct page *page, unsigned int order) { int i; for (i = 0; i < (1 << order); i++) { struct page *p = page + i; if (unlikely(check_new_page(p))) return true; } return false; } inline void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags) { set_page_private(page, 0); set_page_refcounted(page); arch_alloc_page(page, order); debug_pagealloc_map_pages(page, 1 << order); /* * Page unpoisoning must happen before memory initialization. * Otherwise, the poison pattern will be overwritten for __GFP_ZERO * allocations and the page unpoisoning code will complain. */ kernel_unpoison_pages(page, 1 << order); /* * As memory initialization might be integrated into KASAN, * kasan_alloc_pages and kernel_init_free_pages must be * kept together to avoid discrepancies in behavior. */ if (kasan_has_integrated_init()) { kasan_alloc_pages(page, order, gfp_flags); } else { bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags); kasan_unpoison_pages(page, order, init); if (init) kernel_init_free_pages(page, 1 << order, gfp_flags & __GFP_ZEROTAGS); } set_page_owner(page, order, gfp_flags); } static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags, unsigned int alloc_flags) { post_alloc_hook(page, order, gfp_flags); if (order && (gfp_flags & __GFP_COMP)) prep_compound_page(page, order); /* * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to * allocate the page. The expectation is that the caller is taking * steps that will free more memory. The caller should avoid the page * being used for !PFMEMALLOC purposes. */ if (alloc_flags & ALLOC_NO_WATERMARKS) set_page_pfmemalloc(page); else clear_page_pfmemalloc(page); } /* * Go through the free lists for the given migratetype and remove * the smallest available page from the freelists */ static __always_inline struct page *__rmqueue_smallest(struct zone *zone, unsigned int order, int migratetype) { unsigned int current_order; struct free_area *area; struct page *page; /* Find a page of the appropriate size in the preferred list */ for (current_order = order; current_order < MAX_ORDER; ++current_order) { area = &(zone->free_area[current_order]); page = get_page_from_free_area(area, migratetype); if (!page) continue; del_page_from_free_list(page, zone, current_order); expand(zone, page, order, current_order, migratetype); set_pcppage_migratetype(page, migratetype); return page; } return NULL; } /* * This array describes the order lists are fallen back to when * the free lists for the desirable migrate type are depleted */ static int fallbacks[MIGRATE_TYPES][3] = { [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES }, [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, #ifdef CONFIG_CMA [MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */ #endif #ifdef CONFIG_MEMORY_ISOLATION [MIGRATE_ISOLATE] = { MIGRATE_TYPES }, /* Never used */ #endif }; #ifdef CONFIG_CMA static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone, unsigned int order) { return __rmqueue_smallest(zone, order, MIGRATE_CMA); } #else static inline struct page *__rmqueue_cma_fallback(struct zone *zone, unsigned int order) { return NULL; } #endif /* * Move the free pages in a range to the freelist tail of the requested type. * Note that start_page and end_pages are not aligned on a pageblock * boundary. If alignment is required, use move_freepages_block() */ static int move_freepages(struct zone *zone, unsigned long start_pfn, unsigned long end_pfn, int migratetype, int *num_movable) { struct page *page; unsigned long pfn; unsigned int order; int pages_moved = 0; for (pfn = start_pfn; pfn <= end_pfn;) { if (!pfn_valid_within(pfn)) { pfn++; continue; } page = pfn_to_page(pfn); if (!PageBuddy(page)) { /* * We assume that pages that could be isolated for * migration are movable. But we don't actually try * isolating, as that would be expensive. */ if (num_movable && (PageLRU(page) || __PageMovable(page))) (*num_movable)++; pfn++; continue; } /* Make sure we are not inadvertently changing nodes */ VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); VM_BUG_ON_PAGE(page_zone(page) != zone, page); order = buddy_order(page); move_to_free_list(page, zone, order, migratetype); pfn += 1 << order; pages_moved += 1 << order; } return pages_moved; } int move_freepages_block(struct zone *zone, struct page *page, int migratetype, int *num_movable) { unsigned long start_pfn, end_pfn, pfn; if (num_movable) *num_movable = 0; pfn = page_to_pfn(page); start_pfn = pfn & ~(pageblock_nr_pages - 1); end_pfn = start_pfn + pageblock_nr_pages - 1; /* Do not cross zone boundaries */ if (!zone_spans_pfn(zone, start_pfn)) start_pfn = pfn; if (!zone_spans_pfn(zone, end_pfn)) return 0; return move_freepages(zone, start_pfn, end_pfn, migratetype, num_movable); } static void change_pageblock_range(struct page *pageblock_page, int start_order, int migratetype) { int nr_pageblocks = 1 << (start_order - pageblock_order); while (nr_pageblocks--) { set_pageblock_migratetype(pageblock_page, migratetype); pageblock_page += pageblock_nr_pages; } } /* * When we are falling back to another migratetype during allocation, try to * steal extra free pages from the same pageblocks to satisfy further * allocations, instead of polluting multiple pageblocks. * * If we are stealing a relatively large buddy page, it is likely there will * be more free pages in the pageblock, so try to steal them all. For * reclaimable and unmovable allocations, we steal regardless of page size, * as fragmentation caused by those allocations polluting movable pageblocks * is worse than movable allocations stealing from unmovable and reclaimable * pageblocks. */ static bool can_steal_fallback(unsigned int order, int start_mt) { /* * Leaving this order check is intended, although there is * relaxed order check in next check. The reason is that * we can actually steal whole pageblock if this condition met, * but, below check doesn't guarantee it and that is just heuristic * so could be changed anytime. */ if (order >= pageblock_order) return true; if (order >= pageblock_order / 2 || start_mt == MIGRATE_RECLAIMABLE || start_mt == MIGRATE_UNMOVABLE || page_group_by_mobility_disabled) return true; return false; } static inline bool boost_watermark(struct zone *zone) { unsigned long max_boost; if (!watermark_boost_factor) return false; /* * Don't bother in zones that are unlikely to produce results. * On small machines, including kdump capture kernels running * in a small area, boosting the watermark can cause an out of * memory situation immediately. */ if ((pageblock_nr_pages * 4) > zone_managed_pages(zone)) return false; max_boost = mult_frac(zone->_watermark[WMARK_HIGH], watermark_boost_factor, 10000); /* * high watermark may be uninitialised if fragmentation occurs * very early in boot so do not boost. We do not fall * through and boost by pageblock_nr_pages as failing * allocations that early means that reclaim is not going * to help and it may even be impossible to reclaim the * boosted watermark resulting in a hang. */ if (!max_boost) return false; max_boost = max(pageblock_nr_pages, max_boost); zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages, max_boost); return true; } /* * This function implements actual steal behaviour. If order is large enough, * we can steal whole pageblock. If not, we first move freepages in this * pageblock to our migratetype and determine how many already-allocated pages * are there in the pageblock with a compatible migratetype. If at least half * of pages are free or compatible, we can change migratetype of the pageblock * itself, so pages freed in the future will be put on the correct free list. */ static void steal_suitable_fallback(struct zone *zone, struct page *page, unsigned int alloc_flags, int start_type, bool whole_block) { unsigned int current_order = buddy_order(page); int free_pages, movable_pages, alike_pages; int old_block_type; old_block_type = get_pageblock_migratetype(page); /* * This can happen due to races and we want to prevent broken * highatomic accounting. */ if (is_migrate_highatomic(old_block_type)) goto single_page; /* Take ownership for orders >= pageblock_order */ if (current_order >= pageblock_order) { change_pageblock_range(page, current_order, start_type); goto single_page; } /* * Boost watermarks to increase reclaim pressure to reduce the * likelihood of future fallbacks. Wake kswapd now as the node * may be balanced overall and kswapd will not wake naturally. */ if (boost_watermark(zone) && (alloc_flags & ALLOC_KSWAPD)) set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags); /* We are not allowed to try stealing from the whole block */ if (!whole_block) goto single_page; free_pages = move_freepages_block(zone, page, start_type, &movable_pages); /* * Determine how many pages are compatible with our allocation. * For movable allocation, it's the number of movable pages which * we just obtained. For other types it's a bit more tricky. */ if (start_type == MIGRATE_MOVABLE) { alike_pages = movable_pages; } else { /* * If we are falling back a RECLAIMABLE or UNMOVABLE allocation * to MOVABLE pageblock, consider all non-movable pages as * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or * vice versa, be conservative since we can't distinguish the * exact migratetype of non-movable pages. */ if (old_block_type == MIGRATE_MOVABLE) alike_pages = pageblock_nr_pages - (free_pages + movable_pages); else alike_pages = 0; } /* moving whole block can fail due to zone boundary conditions */ if (!free_pages) goto single_page; /* * If a sufficient number of pages in the block are either free or of * comparable migratability as our allocation, claim the whole block. */ if (free_pages + alike_pages >= (1 << (pageblock_order-1)) || page_group_by_mobility_disabled) set_pageblock_migratetype(page, start_type); return; single_page: move_to_free_list(page, zone, current_order, start_type); } /* * Check whether there is a suitable fallback freepage with requested order. * If only_stealable is true, this function returns fallback_mt only if * we can steal other freepages all together. This would help to reduce * fragmentation due to mixed migratetype pages in one pageblock. */ int find_suitable_fallback(struct free_area *area, unsigned int order, int migratetype, bool only_stealable, bool *can_steal) { int i; int fallback_mt; if (area->nr_free == 0) return -1; *can_steal = false; for (i = 0;; i++) { fallback_mt = fallbacks[migratetype][i]; if (fallback_mt == MIGRATE_TYPES) break; if (free_area_empty(area, fallback_mt)) continue; if (can_steal_fallback(order, migratetype)) *can_steal = true; if (!only_stealable) return fallback_mt; if (*can_steal) return fallback_mt; } return -1; } /* * Reserve a pageblock for exclusive use of high-order atomic allocations if * there are no empty page blocks that contain a page with a suitable order */ static void reserve_highatomic_pageblock(struct page *page, struct zone *zone, unsigned int alloc_order) { int mt; unsigned long max_managed, flags; /* * Limit the number reserved to 1 pageblock or roughly 1% of a zone. * Check is race-prone but harmless. */ max_managed = (zone_managed_pages(zone) / 100) + pageblock_nr_pages; if (zone->nr_reserved_highatomic >= max_managed) return; spin_lock_irqsave(&zone->lock, flags); /* Recheck the nr_reserved_highatomic limit under the lock */ if (zone->nr_reserved_highatomic >= max_managed) goto out_unlock; /* Yoink! */ mt = get_pageblock_migratetype(page); if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt) && !is_migrate_cma(mt)) { zone->nr_reserved_highatomic += pageblock_nr_pages; set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC); move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL); } out_unlock: spin_unlock_irqrestore(&zone->lock, flags); } /* * Used when an allocation is about to fail under memory pressure. This * potentially hurts the reliability of high-order allocations when under * intense memory pressure but failed atomic allocations should be easier * to recover from than an OOM. * * If @force is true, try to unreserve a pageblock even though highatomic * pageblock is exhausted. */ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac, bool force) { struct zonelist *zonelist = ac->zonelist; unsigned long flags; struct zoneref *z; struct zone *zone; struct page *page; int order; bool ret; for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->highest_zoneidx, ac->nodemask) { /* * Preserve at least one pageblock unless memory pressure * is really high. */ if (!force && zone->nr_reserved_highatomic <= pageblock_nr_pages) continue; spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { struct free_area *area = &(zone->free_area[order]); page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC); if (!page) continue; /* * In page freeing path, migratetype change is racy so * we can counter several free pages in a pageblock * in this loop although we changed the pageblock type * from highatomic to ac->migratetype. So we should * adjust the count once. */ if (is_migrate_highatomic_page(page)) { /* * It should never happen but changes to * locking could inadvertently allow a per-cpu * drain to add pages to MIGRATE_HIGHATOMIC * while unreserving so be safe and watch for * underflows. */ zone->nr_reserved_highatomic -= min( pageblock_nr_pages, zone->nr_reserved_highatomic); } /* * Convert to ac->migratetype and avoid the normal * pageblock stealing heuristics. Minimally, the caller * is doing the work and needs the pages. More * importantly, if the block was always converted to * MIGRATE_UNMOVABLE or another type then the number * of pageblocks that cannot be completely freed * may increase. */ set_pageblock_migratetype(page, ac->migratetype); ret = move_freepages_block(zone, page, ac->migratetype, NULL); if (ret) { spin_unlock_irqrestore(&zone->lock, flags); return ret; } } spin_unlock_irqrestore(&zone->lock, flags); } return false; } /* * Try finding a free buddy page on the fallback list and put it on the free * list of requested migratetype, possibly along with other pages from the same * block, depending on fragmentation avoidance heuristics. Returns true if * fallback was found so that __rmqueue_smallest() can grab it. * * The use of signed ints for order and current_order is a deliberate * deviation from the rest of this file, to make the for loop * condition simpler. */ static __always_inline bool __rmqueue_fallback(struct zone *zone, int order, int start_migratetype, unsigned int alloc_flags) { struct free_area *area; int current_order; int min_order = order; struct page *page; int fallback_mt; bool can_steal; /* * Do not steal pages from freelists belonging to other pageblocks * i.e. orders < pageblock_order. If there are no local zones free, * the zonelists will be reiterated without ALLOC_NOFRAGMENT. */ if (alloc_flags & ALLOC_NOFRAGMENT) min_order = pageblock_order; /* * Find the largest available free page in the other list. This roughly * approximates finding the pageblock with the most free pages, which * would be too costly to do exactly. */ for (current_order = MAX_ORDER - 1; current_order >= min_order; --current_order) { area = &(zone->free_area[current_order]); fallback_mt = find_suitable_fallback(area, current_order, start_migratetype, false, &can_steal); if (fallback_mt == -1) continue; /* * We cannot steal all free pages from the pageblock and the * requested migratetype is movable. In that case it's better to * steal and split the smallest available page instead of the * largest available page, because even if the next movable * allocation falls back into a different pageblock than this * one, it won't cause permanent fragmentation. */ if (!can_steal && start_migratetype == MIGRATE_MOVABLE && current_order > order) goto find_smallest; goto do_steal; } return false; find_smallest: for (current_order = order; current_order < MAX_ORDER; current_order++) { area = &(zone->free_area[current_order]); fallback_mt = find_suitable_fallback(area, current_order, start_migratetype, false, &can_steal); if (fallback_mt != -1) break; } /* * This should not happen - we already found a suitable fallback * when looking for the largest page. */ VM_BUG_ON(current_order == MAX_ORDER); do_steal: page = get_page_from_free_area(area, fallback_mt); steal_suitable_fallback(zone, page, alloc_flags, start_migratetype, can_steal); trace_mm_page_alloc_extfrag(page, order, current_order, start_migratetype, fallback_mt); return true; } /* * Do the hard work of removing an element from the buddy allocator. * Call me with the zone->lock already held. */ static __always_inline struct page * __rmqueue(struct zone *zone, unsigned int order, int migratetype, unsigned int alloc_flags) { struct page *page; if (IS_ENABLED(CONFIG_CMA)) { /* * Balance movable allocations between regular and CMA areas by * allocating from CMA when over half of the zone's free memory * is in the CMA area. */ if (alloc_flags & ALLOC_CMA && zone_page_state(zone, NR_FREE_CMA_PAGES) > zone_page_state(zone, NR_FREE_PAGES) / 2) { page = __rmqueue_cma_fallback(zone, order); if (page) goto out; } } retry: page = __rmqueue_smallest(zone, order, migratetype); if (unlikely(!page)) { if (alloc_flags & ALLOC_CMA) page = __rmqueue_cma_fallback(zone, order); if (!page && __rmqueue_fallback(zone, order, migratetype, alloc_flags)) goto retry; } out: if (page) trace_mm_page_alloc_zone_locked(page, order, migratetype); return page; } /* * Obtain a specified number of elements from the buddy allocator, all under * a single hold of the lock, for efficiency. Add them to the supplied list. * Returns the number of new pages which were placed at *list. */ static int rmqueue_bulk(struct zone *zone, unsigned int order, unsigned long count, struct list_head *list, int migratetype, unsigned int alloc_flags) { int i, allocated = 0; spin_lock(&zone->lock); for (i = 0; i < count; ++i) { struct page *page = __rmqueue(zone, order, migratetype, alloc_flags); if (unlikely(page == NULL)) break; if (unlikely(check_pcp_refill(page))) continue; /* * Split buddy pages returned by expand() are received here in * physical page order. The page is added to the tail of * caller's list. From the callers perspective, the linked list * is ordered by page number under some conditions. This is * useful for IO devices that can forward direction from the * head, thus also in the physical page order. This is useful * for IO devices that can merge IO requests if the physical * pages are ordered properly. */ list_add_tail(&page->lru, list); allocated++; if (is_migrate_cma(get_pcppage_migratetype(page))) __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, -(1 << order)); } /* * i pages were removed from the buddy list even if some leak due * to check_pcp_refill failing so adjust NR_FREE_PAGES based * on i. Do not confuse with 'allocated' which is the number of * pages added to the pcp list. */ __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order)); spin_unlock(&zone->lock); return allocated; } #ifdef CONFIG_NUMA /* * Called from the vmstat counter updater to drain pagesets of this * currently executing processor on remote nodes after they have * expired. * * Note that this function must be called with the thread pinned to * a single processor. */ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp) { unsigned long flags; int to_drain, batch; local_irq_save(flags); batch = READ_ONCE(pcp->batch); to_drain = min(pcp->count, batch); if (to_drain > 0) free_pcppages_bulk(zone, to_drain, pcp); local_irq_restore(flags); } #endif /* * Drain pcplists of the indicated processor and zone. * * The processor must either be the current processor and the * thread pinned to the current processor or a processor that * is not online. */ static void drain_pages_zone(unsigned int cpu, struct zone *zone) { unsigned long flags; struct per_cpu_pageset *pset; struct per_cpu_pages *pcp; local_irq_save(flags); pset = per_cpu_ptr(zone->pageset, cpu); pcp = &pset->pcp; if (pcp->count) free_pcppages_bulk(zone, pcp->count, pcp); local_irq_restore(flags); } /* * Drain pcplists of all zones on the indicated processor. * * The processor must either be the current processor and the * thread pinned to the current processor or a processor that * is not online. */ static void drain_pages(unsigned int cpu) { struct zone *zone; for_each_populated_zone(zone) { drain_pages_zone(cpu, zone); } } /* * Spill all of this CPU's per-cpu pages back into the buddy allocator. * * The CPU has to be pinned. When zone parameter is non-NULL, spill just * the single zone's pages. */ void drain_local_pages(struct zone *zone) { int cpu = smp_processor_id(); if (zone) drain_pages_zone(cpu, zone); else drain_pages(cpu); } static void drain_local_pages_wq(struct work_struct *work) { struct pcpu_drain *drain; drain = container_of(work, struct pcpu_drain, work); /* * drain_all_pages doesn't use proper cpu hotplug protection so * we can race with cpu offline when the WQ can move this from * a cpu pinned worker to an unbound one. We can operate on a different * cpu which is alright but we also have to make sure to not move to * a different one. */ preempt_disable(); drain_local_pages(drain->zone); preempt_enable(); } /* * The implementation of drain_all_pages(), exposing an extra parameter to * drain on all cpus. * * drain_all_pages() is optimized to only execute on cpus where pcplists are * not empty. The check for non-emptiness can however race with a free to * pcplist that has not yet increased the pcp->count from 0 to 1. Callers * that need the guarantee that every CPU has drained can disable the * optimizing racy check. */ static void __drain_all_pages(struct zone *zone, bool force_all_cpus) { int cpu; /* * Allocate in the BSS so we wont require allocation in * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y */ static cpumask_t cpus_with_pcps; /* * Make sure nobody triggers this path before mm_percpu_wq is fully * initialized. */ if (WARN_ON_ONCE(!mm_percpu_wq)) return; /* * Do not drain if one is already in progress unless it's specific to * a zone. Such callers are primarily CMA and memory hotplug and need * the drain to be complete when the call returns. */ if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) { if (!zone) return; mutex_lock(&pcpu_drain_mutex); } /* * We don't care about racing with CPU hotplug event * as offline notification will cause the notified * cpu to drain that CPU pcps and on_each_cpu_mask * disables preemption as part of its processing */ for_each_online_cpu(cpu) { struct per_cpu_pageset *pcp; struct zone *z; bool has_pcps = false; if (force_all_cpus) { /* * The pcp.count check is racy, some callers need a * guarantee that no cpu is missed. */ has_pcps = true; } else if (zone) { pcp = per_cpu_ptr(zone->pageset, cpu); if (pcp->pcp.count) has_pcps = true; } else { for_each_populated_zone(z) { pcp = per_cpu_ptr(z->pageset, cpu); if (pcp->pcp.count) { has_pcps = true; break; } } } if (has_pcps) cpumask_set_cpu(cpu, &cpus_with_pcps); else cpumask_clear_cpu(cpu, &cpus_with_pcps); } for_each_cpu(cpu, &cpus_with_pcps) { struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu); drain->zone = zone; INIT_WORK(&drain->work, drain_local_pages_wq); queue_work_on(cpu, mm_percpu_wq, &drain->work); } for_each_cpu(cpu, &cpus_with_pcps) flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work); mutex_unlock(&pcpu_drain_mutex); } /* * Spill all the per-cpu pages from all CPUs back into the buddy allocator. * * When zone parameter is non-NULL, spill just the single zone's pages. * * Note that this can be extremely slow as the draining happens in a workqueue. */ void drain_all_pages(struct zone *zone) { __drain_all_pages(zone, false); } #ifdef CONFIG_HIBERNATION /* * Touch the watchdog for every WD_PAGE_COUNT pages. */ #define WD_PAGE_COUNT (128*1024) void mark_free_pages(struct zone *zone) { unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT; unsigned long flags; unsigned int order, t; struct page *page; if (zone_is_empty(zone)) return; spin_lock_irqsave(&zone->lock, flags); max_zone_pfn = zone_end_pfn(zone); for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) if (pfn_valid(pfn)) { page = pfn_to_page(pfn); if (!--page_count) { touch_nmi_watchdog(); page_count = WD_PAGE_COUNT; } if (page_zone(page) != zone) continue; if (!swsusp_page_is_forbidden(page)) swsusp_unset_page_free(page); } for_each_migratetype_order(order, t) { list_for_each_entry(page, &zone->free_area[order].free_list[t], lru) { unsigned long i; pfn = page_to_pfn(page); for (i = 0; i < (1UL << order); i++) { if (!--page_count) { touch_nmi_watchdog(); page_count = WD_PAGE_COUNT; } swsusp_set_page_free(pfn_to_page(pfn + i)); } } } spin_unlock_irqrestore(&zone->lock, flags); } #endif /* CONFIG_PM */ static bool free_unref_page_prepare(struct page *page, unsigned long pfn) { int migratetype; if (!free_pcp_prepare(page)) return false; migratetype = get_pfnblock_migratetype(page, pfn); set_pcppage_migratetype(page, migratetype); return true; } static void free_unref_page_commit(struct page *page, unsigned long pfn) { struct zone *zone = page_zone(page); struct per_cpu_pages *pcp; int migratetype; migratetype = get_pcppage_migratetype(page); __count_vm_event(PGFREE); /* * We only track unmovable, reclaimable and movable on pcp lists. * Free ISOLATE pages back to the allocator because they are being * offlined but treat HIGHATOMIC as movable pages so we can get those * areas back if necessary. Otherwise, we may have to free * excessively into the page allocator */ if (migratetype >= MIGRATE_PCPTYPES) { if (unlikely(is_migrate_isolate(migratetype))) { free_one_page(zone, page, pfn, 0, migratetype, FPI_NONE); return; } migratetype = MIGRATE_MOVABLE; } pcp = &this_cpu_ptr(zone->pageset)->pcp; list_add(&page->lru, &pcp->lists[migratetype]); pcp->count++; if (pcp->count >= READ_ONCE(pcp->high)) free_pcppages_bulk(zone, READ_ONCE(pcp->batch), pcp); } /* * Free a 0-order page */ void free_unref_page(struct page *page) { unsigned long flags; unsigned long pfn = page_to_pfn(page); if (!free_unref_page_prepare(page, pfn)) return; local_irq_save(flags); free_unref_page_commit(page, pfn); local_irq_restore(flags); } /* * Free a list of 0-order pages */ void free_unref_page_list(struct list_head *list) { struct page *page, *next; unsigned long flags, pfn; int batch_count = 0; /* Prepare pages for freeing */ list_for_each_entry_safe(page, next, list, lru) { pfn = page_to_pfn(page); if (!free_unref_page_prepare(page, pfn)) list_del(&page->lru); set_page_private(page, pfn); } local_irq_save(flags); list_for_each_entry_safe(page, next, list, lru) { unsigned long pfn = page_private(page); set_page_private(page, 0); trace_mm_page_free_batched(page); free_unref_page_commit(page, pfn); /* * Guard against excessive IRQ disabled times when we get * a large list of pages to free. */ if (++batch_count == SWAP_CLUSTER_MAX) { local_irq_restore(flags); batch_count = 0; local_irq_save(flags); } } local_irq_restore(flags); } /* * split_page takes a non-compound higher-order page, and splits it into * n (1<_watermark[WMARK_MIN] + (1UL << order); if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA)) return 0; __mod_zone_freepage_state(zone, -(1UL << order), mt); } /* Remove page from free list */ del_page_from_free_list(page, zone, order); /* * Set the pageblock if the isolated page is at least half of a * pageblock */ if (order >= pageblock_order - 1) { struct page *endpage = page + (1 << order) - 1; for (; page < endpage; page += pageblock_nr_pages) { int mt = get_pageblock_migratetype(page); if (!is_migrate_isolate(mt) && !is_migrate_cma(mt) && !is_migrate_highatomic(mt)) set_pageblock_migratetype(page, MIGRATE_MOVABLE); } } return 1UL << order; } /** * __putback_isolated_page - Return a now-isolated page back where we got it * @page: Page that was isolated * @order: Order of the isolated page * @mt: The page's pageblock's migratetype * * This function is meant to return a page pulled from the free lists via * __isolate_free_page back to the free lists they were pulled from. */ void __putback_isolated_page(struct page *page, unsigned int order, int mt) { struct zone *zone = page_zone(page); /* zone lock should be held when this function is called */ lockdep_assert_held(&zone->lock); /* Return isolated page to tail of freelist. */ __free_one_page(page, page_to_pfn(page), zone, order, mt, FPI_SKIP_REPORT_NOTIFY | FPI_TO_TAIL); } /* * Update NUMA hit/miss statistics * * Must be called with interrupts disabled. */ static inline void zone_statistics(struct zone *preferred_zone, struct zone *z) { #ifdef CONFIG_NUMA enum numa_stat_item local_stat = NUMA_LOCAL; /* skip numa counters update if numa stats is disabled */ if (!static_branch_likely(&vm_numa_stat_key)) return; if (zone_to_nid(z) != numa_node_id()) local_stat = NUMA_OTHER; if (zone_to_nid(z) == zone_to_nid(preferred_zone)) __inc_numa_state(z, NUMA_HIT); else { __inc_numa_state(z, NUMA_MISS); __inc_numa_state(preferred_zone, NUMA_FOREIGN); } __inc_numa_state(z, local_stat); #endif } /* Remove page from the per-cpu list, caller must protect the list */ static inline struct page *__rmqueue_pcplist(struct zone *zone, int migratetype, unsigned int alloc_flags, struct per_cpu_pages *pcp, struct list_head *list) { struct page *page; do { if (list_empty(list)) { pcp->count += rmqueue_bulk(zone, 0, READ_ONCE(pcp->batch), list, migratetype, alloc_flags); if (unlikely(list_empty(list))) return NULL; } page = list_first_entry(list, struct page, lru); list_del(&page->lru); pcp->count--; } while (check_new_pcp(page)); return page; } /* Lock and remove page from the per-cpu list */ static struct page *rmqueue_pcplist(struct zone *preferred_zone, struct zone *zone, gfp_t gfp_flags, int migratetype, unsigned int alloc_flags) { struct per_cpu_pages *pcp; struct list_head *list; struct page *page; unsigned long flags; local_irq_save(flags); pcp = &this_cpu_ptr(zone->pageset)->pcp; list = &pcp->lists[migratetype]; page = __rmqueue_pcplist(zone, migratetype, alloc_flags, pcp, list); if (page) { __count_zid_vm_events(PGALLOC, page_zonenum(page), 1); zone_statistics(preferred_zone, zone); } local_irq_restore(flags); return page; } /* * Allocate a page from the given zone. Use pcplists for order-0 allocations. */ static inline struct page *rmqueue(struct zone *preferred_zone, struct zone *zone, unsigned int order, gfp_t gfp_flags, unsigned int alloc_flags, int migratetype) { unsigned long flags; struct page *page; if (likely(order == 0)) { /* * MIGRATE_MOVABLE pcplist could have the pages on CMA area and * we need to skip it when CMA area isn't allowed. */ if (!IS_ENABLED(CONFIG_CMA) || alloc_flags & ALLOC_CMA || migratetype != MIGRATE_MOVABLE) { page = rmqueue_pcplist(preferred_zone, zone, gfp_flags, migratetype, alloc_flags); goto out; } } /* * We most definitely don't want callers attempting to * allocate greater than order-1 page units with __GFP_NOFAIL. */ WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1)); spin_lock_irqsave(&zone->lock, flags); do { page = NULL; /* * order-0 request can reach here when the pcplist is skipped * due to non-CMA allocation context. HIGHATOMIC area is * reserved for high-order atomic allocation, so order-0 * request should skip it. */ if (order > 0 && alloc_flags & ALLOC_HARDER) { page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC); if (page) trace_mm_page_alloc_zone_locked(page, order, migratetype); } if (!page) page = __rmqueue(zone, order, migratetype, alloc_flags); } while (page && check_new_pages(page, order)); spin_unlock(&zone->lock); if (!page) goto failed; __mod_zone_freepage_state(zone, -(1 << order), get_pcppage_migratetype(page)); __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); zone_statistics(preferred_zone, zone); local_irq_restore(flags); out: /* Separate test+clear to avoid unnecessary atomics */ if (test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags)) { clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags); wakeup_kswapd(zone, 0, 0, zone_idx(zone)); } VM_BUG_ON_PAGE(page && bad_range(zone, page), page); return page; failed: local_irq_restore(flags); return NULL; } #ifdef CONFIG_FAIL_PAGE_ALLOC static struct { struct fault_attr attr; bool ignore_gfp_highmem; bool ignore_gfp_reclaim; u32 min_order; } fail_page_alloc = { .attr = FAULT_ATTR_INITIALIZER, .ignore_gfp_reclaim = true, .ignore_gfp_highmem = true, .min_order = 1, }; static int __init setup_fail_page_alloc(char *str) { return setup_fault_attr(&fail_page_alloc.attr, str); } __setup("fail_page_alloc=", setup_fail_page_alloc); static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) { if (order < fail_page_alloc.min_order) return false; if (gfp_mask & __GFP_NOFAIL) return false; if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM)) return false; if (fail_page_alloc.ignore_gfp_reclaim && (gfp_mask & __GFP_DIRECT_RECLAIM)) return false; return should_fail(&fail_page_alloc.attr, 1 << order); } #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS static int __init fail_page_alloc_debugfs(void) { umode_t mode = S_IFREG | 0600; struct dentry *dir; dir = fault_create_debugfs_attr("fail_page_alloc", NULL, &fail_page_alloc.attr); debugfs_create_bool("ignore-gfp-wait", mode, dir, &fail_page_alloc.ignore_gfp_reclaim); debugfs_create_bool("ignore-gfp-highmem", mode, dir, &fail_page_alloc.ignore_gfp_highmem); debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order); return 0; } late_initcall(fail_page_alloc_debugfs); #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ #else /* CONFIG_FAIL_PAGE_ALLOC */ static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) { return false; } #endif /* CONFIG_FAIL_PAGE_ALLOC */ noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) { return __should_fail_alloc_page(gfp_mask, order); } ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE); static inline long __zone_watermark_unusable_free(struct zone *z, unsigned int order, unsigned int alloc_flags) { const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM)); long unusable_free = (1 << order) - 1; /* * If the caller does not have rights to ALLOC_HARDER then subtract * the high-atomic reserves. This will over-estimate the size of the * atomic reserve but it avoids a search. */ if (likely(!alloc_harder)) unusable_free += z->nr_reserved_highatomic; #ifdef CONFIG_CMA /* If allocation can't use CMA areas don't use free CMA pages */ if (!(alloc_flags & ALLOC_CMA)) unusable_free += zone_page_state(z, NR_FREE_CMA_PAGES); #endif return unusable_free; } /* * Return true if free base pages are above 'mark'. For high-order checks it * will return true of the order-0 watermark is reached and there is at least * one free page of a suitable size. Checking now avoids taking the zone lock * to check in the allocation paths if no pages are free. */ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, int highest_zoneidx, unsigned int alloc_flags, long free_pages) { long min = mark; int o; const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM)); /* free_pages may go negative - that's OK */ free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags); if (alloc_flags & ALLOC_HIGH) min -= min / 2; if (unlikely(alloc_harder)) { /* * OOM victims can try even harder than normal ALLOC_HARDER * users on the grounds that it's definitely going to be in * the exit path shortly and free memory. Any allocation it * makes during the free path will be small and short-lived. */ if (alloc_flags & ALLOC_OOM) min -= min / 2; else min -= min / 4; } /* * Check watermarks for an order-0 allocation request. If these * are not met, then a high-order request also cannot go ahead * even if a suitable page happened to be free. */ if (free_pages <= min + z->lowmem_reserve[highest_zoneidx]) return false; /* If this is an order-0 request then the watermark is fine */ if (!order) return true; /* For a high-order request, check at least one suitable page is free */ for (o = order; o < MAX_ORDER; o++) { struct free_area *area = &z->free_area[o]; int mt; if (!area->nr_free) continue; for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) { if (!free_area_empty(area, mt)) return true; } #ifdef CONFIG_CMA if ((alloc_flags & ALLOC_CMA) && !free_area_empty(area, MIGRATE_CMA)) { return true; } #endif if (alloc_harder && !free_area_empty(area, MIGRATE_HIGHATOMIC)) return true; } return false; } bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, int highest_zoneidx, unsigned int alloc_flags) { return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, zone_page_state(z, NR_FREE_PAGES)); } static inline bool zone_watermark_fast(struct zone *z, unsigned int order, unsigned long mark, int highest_zoneidx, unsigned int alloc_flags, gfp_t gfp_mask) { long free_pages; free_pages = zone_page_state(z, NR_FREE_PAGES); /* * Fast check for order-0 only. If this fails then the reserves * need to be calculated. */ if (!order) { long fast_free; fast_free = free_pages; fast_free -= __zone_watermark_unusable_free(z, 0, alloc_flags); if (fast_free > mark + z->lowmem_reserve[highest_zoneidx]) return true; } if (__zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, free_pages)) return true; /* * Ignore watermark boosting for GFP_ATOMIC order-0 allocations * when checking the min watermark. The min watermark is the * point where boosting is ignored so that kswapd is woken up * when below the low watermark. */ if (unlikely(!order && (gfp_mask & __GFP_ATOMIC) && z->watermark_boost && ((alloc_flags & ALLOC_WMARK_MASK) == WMARK_MIN))) { mark = z->_watermark[WMARK_MIN]; return __zone_watermark_ok(z, order, mark, highest_zoneidx, alloc_flags, free_pages); } return false; } bool zone_watermark_ok_safe(struct zone *z, unsigned int order, unsigned long mark, int highest_zoneidx) { long free_pages = zone_page_state(z, NR_FREE_PAGES); if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark) free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES); return __zone_watermark_ok(z, order, mark, highest_zoneidx, 0, free_pages); } #ifdef CONFIG_NUMA static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) { return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <= node_reclaim_distance; } #else /* CONFIG_NUMA */ static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) { return true; } #endif /* CONFIG_NUMA */ /* * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid * fragmentation is subtle. If the preferred zone was HIGHMEM then * premature use of a lower zone may cause lowmem pressure problems that * are worse than fragmentation. If the next zone is ZONE_DMA then it is * probably too small. It only makes sense to spread allocations to avoid * fragmentation between the Normal and DMA32 zones. */ static inline unsigned int alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask) { unsigned int alloc_flags; /* * __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD * to save a branch. */ alloc_flags = (__force int) (gfp_mask & __GFP_KSWAPD_RECLAIM); #ifdef CONFIG_ZONE_DMA32 if (!zone) return alloc_flags; if (zone_idx(zone) != ZONE_NORMAL) return alloc_flags; /* * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and * the pointer is within zone->zone_pgdat->node_zones[]. Also assume * on UMA that if Normal is populated then so is DMA32. */ BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1); if (nr_online_nodes > 1 && !populated_zone(--zone)) return alloc_flags; alloc_flags |= ALLOC_NOFRAGMENT; #endif /* CONFIG_ZONE_DMA32 */ return alloc_flags; } /* Must be called after current_gfp_context() which can change gfp_mask */ static inline unsigned int gfp_to_alloc_flags_cma(gfp_t gfp_mask, unsigned int alloc_flags) { #ifdef CONFIG_CMA if (gfp_migratetype(gfp_mask) == MIGRATE_MOVABLE) alloc_flags |= ALLOC_CMA; #endif return alloc_flags; } /* * get_page_from_freelist goes through the zonelist trying to allocate * a page. */ static struct page * get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, const struct alloc_context *ac) { struct zoneref *z; struct zone *zone; struct pglist_data *last_pgdat_dirty_limit = NULL; bool no_fallback; retry: /* * Scan zonelist, looking for a zone with enough free. * See also __cpuset_node_allowed() comment in kernel/cpuset.c. */ no_fallback = alloc_flags & ALLOC_NOFRAGMENT; z = ac->preferred_zoneref; for_next_zone_zonelist_nodemask(zone, z, ac->highest_zoneidx, ac->nodemask) { struct page *page; unsigned long mark; if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) && !__cpuset_zone_allowed(zone, gfp_mask)) continue; /* * When allocating a page cache page for writing, we * want to get it from a node that is within its dirty * limit, such that no single node holds more than its * proportional share of globally allowed dirty pages. * The dirty limits take into account the node's * lowmem reserves and high watermark so that kswapd * should be able to balance it without having to * write pages from its LRU list. * * XXX: For now, allow allocations to potentially * exceed the per-node dirty limit in the slowpath * (spread_dirty_pages unset) before going into reclaim, * which is important when on a NUMA setup the allowed * nodes are together not big enough to reach the * global limit. The proper fix for these situations * will require awareness of nodes in the * dirty-throttling and the flusher threads. */ if (ac->spread_dirty_pages) { if (last_pgdat_dirty_limit == zone->zone_pgdat) continue; if (!node_dirty_ok(zone->zone_pgdat)) { last_pgdat_dirty_limit = zone->zone_pgdat; continue; } } if (no_fallback && nr_online_nodes > 1 && zone != ac->preferred_zoneref->zone) { int local_nid; /* * If moving to a remote node, retry but allow * fragmenting fallbacks. Locality is more important * than fragmentation avoidance. */ local_nid = zone_to_nid(ac->preferred_zoneref->zone); if (zone_to_nid(zone) != local_nid) { alloc_flags &= ~ALLOC_NOFRAGMENT; goto retry; } } mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK); if (!zone_watermark_fast(zone, order, mark, ac->highest_zoneidx, alloc_flags, gfp_mask)) { int ret; #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT /* * Watermark failed for this zone, but see if we can * grow this zone if it contains deferred pages. */ if (static_branch_unlikely(&deferred_pages)) { if (_deferred_grow_zone(zone, order)) goto try_this_zone; } #endif /* Checked here to keep the fast path fast */ BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK); if (alloc_flags & ALLOC_NO_WATERMARKS) goto try_this_zone; if (!node_reclaim_enabled() || !zone_allows_reclaim(ac->preferred_zoneref->zone, zone)) continue; ret = node_reclaim(zone->zone_pgdat, gfp_mask, order); switch (ret) { case NODE_RECLAIM_NOSCAN: /* did not scan */ continue; case NODE_RECLAIM_FULL: /* scanned but unreclaimable */ continue; default: /* did we reclaim enough */ if (zone_watermark_ok(zone, order, mark, ac->highest_zoneidx, alloc_flags)) goto try_this_zone; continue; } } try_this_zone: page = rmqueue(ac->preferred_zoneref->zone, zone, order, gfp_mask, alloc_flags, ac->migratetype); if (page) { prep_new_page(page, order, gfp_mask, alloc_flags); /* * If this is a high-order atomic allocation then check * if the pageblock should be reserved for the future */ if (unlikely(order && (alloc_flags & ALLOC_HARDER))) reserve_highatomic_pageblock(page, zone, order); return page; } else { #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT /* Try again if zone has deferred pages */ if (static_branch_unlikely(&deferred_pages)) { if (_deferred_grow_zone(zone, order)) goto try_this_zone; } #endif } } /* * It's possible on a UMA machine to get through all zones that are * fragmented. If avoiding fragmentation, reset and try again. */ if (no_fallback) { alloc_flags &= ~ALLOC_NOFRAGMENT; goto retry; } return NULL; } static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask) { unsigned int filter = SHOW_MEM_FILTER_NODES; /* * This documents exceptions given to allocations in certain * contexts that are allowed to allocate outside current's set * of allowed nodes. */ if (!(gfp_mask & __GFP_NOMEMALLOC)) if (tsk_is_oom_victim(current) || (current->flags & (PF_MEMALLOC | PF_EXITING))) filter &= ~SHOW_MEM_FILTER_NODES; if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM)) filter &= ~SHOW_MEM_FILTER_NODES; show_mem(filter, nodemask); } void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...) { struct va_format vaf; va_list args; static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1); if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs)) return; va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl", current->comm, &vaf, gfp_mask, &gfp_mask, nodemask_pr_args(nodemask)); va_end(args); cpuset_print_current_mems_allowed(); pr_cont("\n"); dump_stack(); warn_alloc_show_mem(gfp_mask, nodemask); } static inline struct page * __alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order, unsigned int alloc_flags, const struct alloc_context *ac) { struct page *page; page = get_page_from_freelist(gfp_mask, order, alloc_flags|ALLOC_CPUSET, ac); /* * fallback to ignore cpuset restriction if our nodes * are depleted */ if (!page) page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); return page; } static inline struct page * __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order, const struct alloc_context *ac, unsigned long *did_some_progress) { struct oom_control oc = { .zonelist = ac->zonelist, .nodemask = ac->nodemask, .memcg = NULL, .gfp_mask = gfp_mask, .order = order, }; struct page *page; *did_some_progress = 0; /* * Acquire the oom lock. If that fails, somebody else is * making progress for us. */ if (!mutex_trylock(&oom_lock)) { *did_some_progress = 1; schedule_timeout_uninterruptible(1); return NULL; } /* * Go through the zonelist yet one more time, keep very high watermark * here, this is only to catch a parallel oom killing, we must fail if * we're still under heavy pressure. But make sure that this reclaim * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY * allocation which will never fail due to oom_lock already held. */ page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) & ~__GFP_DIRECT_RECLAIM, order, ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac); if (page) goto out; /* Coredumps can quickly deplete all memory reserves */ if (current->flags & PF_DUMPCORE) goto out; /* The OOM killer will not help higher order allocs */ if (order > PAGE_ALLOC_COSTLY_ORDER) goto out; /* * We have already exhausted all our reclaim opportunities without any * success so it is time to admit defeat. We will skip the OOM killer * because it is very likely that the caller has a more reasonable * fallback than shooting a random task. * * The OOM killer may not free memory on a specific node. */ if (gfp_mask & (__GFP_RETRY_MAYFAIL | __GFP_THISNODE)) goto out; /* The OOM killer does not needlessly kill tasks for lowmem */ if (ac->highest_zoneidx < ZONE_NORMAL) goto out; if (pm_suspended_storage()) goto out; /* * XXX: GFP_NOFS allocations should rather fail than rely on * other request to make a forward progress. * We are in an unfortunate situation where out_of_memory cannot * do much for this context but let's try it to at least get * access to memory reserved if the current task is killed (see * out_of_memory). Once filesystems are ready to handle allocation * failures more gracefully we should just bail out here. */ /* Exhausted what can be done so it's blame time */ if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) { *did_some_progress = 1; /* * Help non-failing allocations by giving them access to memory * reserves */ if (gfp_mask & __GFP_NOFAIL) page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_NO_WATERMARKS, ac); } out: mutex_unlock(&oom_lock); return page; } /* * Maximum number of compaction retries with a progress before OOM * killer is consider as the only way to move forward. */ #define MAX_COMPACT_RETRIES 16 #ifdef CONFIG_COMPACTION /* Try memory compaction for high-order allocations before reclaim */ static struct page * __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, unsigned int alloc_flags, const struct alloc_context *ac, enum compact_priority prio, enum compact_result *compact_result) { struct page *page = NULL; unsigned long pflags; unsigned int noreclaim_flag; if (!order) return NULL; psi_memstall_enter(&pflags); noreclaim_flag = memalloc_noreclaim_save(); *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac, prio, &page); memalloc_noreclaim_restore(noreclaim_flag); psi_memstall_leave(&pflags); if (*compact_result == COMPACT_SKIPPED) return NULL; /* * At least in one zone compaction wasn't deferred or skipped, so let's * count a compaction stall */ count_vm_event(COMPACTSTALL); /* Prep a captured page if available */ if (page) prep_new_page(page, order, gfp_mask, alloc_flags); /* Try get a page from the freelist if available */ if (!page) page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); if (page) { struct zone *zone = page_zone(page); zone->compact_blockskip_flush = false; compaction_defer_reset(zone, order, true); count_vm_event(COMPACTSUCCESS); return page; } /* * It's bad if compaction run occurs and fails. The most likely reason * is that pages exist, but not enough to satisfy watermarks. */ count_vm_event(COMPACTFAIL); cond_resched(); return NULL; } static inline bool should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, enum compact_result compact_result, enum compact_priority *compact_priority, int *compaction_retries) { int max_retries = MAX_COMPACT_RETRIES; int min_priority; bool ret = false; int retries = *compaction_retries; enum compact_priority priority = *compact_priority; if (!order) return false; if (compaction_made_progress(compact_result)) (*compaction_retries)++; /* * compaction considers all the zone as desperately out of memory * so it doesn't really make much sense to retry except when the * failure could be caused by insufficient priority */ if (compaction_failed(compact_result)) goto check_priority; /* * compaction was skipped because there are not enough order-0 pages * to work with, so we retry only if it looks like reclaim can help. */ if (compaction_needs_reclaim(compact_result)) { ret = compaction_zonelist_suitable(ac, order, alloc_flags); goto out; } /* * make sure the compaction wasn't deferred or didn't bail out early * due to locks contention before we declare that we should give up. * But the next retry should use a higher priority if allowed, so * we don't just keep bailing out endlessly. */ if (compaction_withdrawn(compact_result)) { goto check_priority; } /* * !costly requests are much more important than __GFP_RETRY_MAYFAIL * costly ones because they are de facto nofail and invoke OOM * killer to move on while costly can fail and users are ready * to cope with that. 1/4 retries is rather arbitrary but we * would need much more detailed feedback from compaction to * make a better decision. */ if (order > PAGE_ALLOC_COSTLY_ORDER) max_retries /= 4; if (*compaction_retries <= max_retries) { ret = true; goto out; } /* * Make sure there are attempts at the highest priority if we exhausted * all retries or failed at the lower priorities. */ check_priority: min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ? MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY; if (*compact_priority > min_priority) { (*compact_priority)--; *compaction_retries = 0; ret = true; } out: trace_compact_retry(order, priority, compact_result, retries, max_retries, ret); return ret; } #else static inline struct page * __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, unsigned int alloc_flags, const struct alloc_context *ac, enum compact_priority prio, enum compact_result *compact_result) { *compact_result = COMPACT_SKIPPED; return NULL; } static inline bool should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags, enum compact_result compact_result, enum compact_priority *compact_priority, int *compaction_retries) { struct zone *zone; struct zoneref *z; if (!order || order > PAGE_ALLOC_COSTLY_ORDER) return false; /* * There are setups with compaction disabled which would prefer to loop * inside the allocator rather than hit the oom killer prematurely. * Let's give them a good hope and keep retrying while the order-0 * watermarks are OK. */ for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->highest_zoneidx, ac->nodemask) { if (zone_watermark_ok(zone, 0, min_wmark_pages(zone), ac->highest_zoneidx, alloc_flags)) return true; } return false; } #endif /* CONFIG_COMPACTION */ #ifdef CONFIG_LOCKDEP static struct lockdep_map __fs_reclaim_map = STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map); static bool __need_reclaim(gfp_t gfp_mask) { /* no reclaim without waiting on it */ if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) return false; /* this guy won't enter reclaim */ if (current->flags & PF_MEMALLOC) return false; if (gfp_mask & __GFP_NOLOCKDEP) return false; return true; } void __fs_reclaim_acquire(void) { lock_map_acquire(&__fs_reclaim_map); } void __fs_reclaim_release(void) { lock_map_release(&__fs_reclaim_map); } void fs_reclaim_acquire(gfp_t gfp_mask) { gfp_mask = current_gfp_context(gfp_mask); if (__need_reclaim(gfp_mask)) { if (gfp_mask & __GFP_FS) __fs_reclaim_acquire(); #ifdef CONFIG_MMU_NOTIFIER lock_map_acquire(&__mmu_notifier_invalidate_range_start_map); lock_map_release(&__mmu_notifier_invalidate_range_start_map); #endif } } EXPORT_SYMBOL_GPL(fs_reclaim_acquire); void fs_reclaim_release(gfp_t gfp_mask) { gfp_mask = current_gfp_context(gfp_mask); if (__need_reclaim(gfp_mask)) { if (gfp_mask & __GFP_FS) __fs_reclaim_release(); } } EXPORT_SYMBOL_GPL(fs_reclaim_release); #endif /* Perform direct synchronous page reclaim */ static unsigned long __perform_reclaim(gfp_t gfp_mask, unsigned int order, const struct alloc_context *ac) { unsigned int noreclaim_flag; unsigned long pflags, progress; cond_resched(); /* We now go into synchronous reclaim */ cpuset_memory_pressure_bump(); psi_memstall_enter(&pflags); fs_reclaim_acquire(gfp_mask); noreclaim_flag = memalloc_noreclaim_save(); progress = try_to_free_pages(ac->zonelist, order, gfp_mask, ac->nodemask); memalloc_noreclaim_restore(noreclaim_flag); fs_reclaim_release(gfp_mask); psi_memstall_leave(&pflags); cond_resched(); return progress; } /* The really slow allocator path where we enter direct reclaim */ static inline struct page * __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order, unsigned int alloc_flags, const struct alloc_context *ac, unsigned long *did_some_progress) { struct page *page = NULL; bool drained = false; *did_some_progress = __perform_reclaim(gfp_mask, order, ac); if (unlikely(!(*did_some_progress))) return NULL; retry: page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); /* * If an allocation failed after direct reclaim, it could be because * pages are pinned on the per-cpu lists or in high alloc reserves. * Shrink them and try again */ if (!page && !drained) { unreserve_highatomic_pageblock(ac, false); drain_all_pages(NULL); drained = true; goto retry; } return page; } static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask, const struct alloc_context *ac) { struct zoneref *z; struct zone *zone; pg_data_t *last_pgdat = NULL; enum zone_type highest_zoneidx = ac->highest_zoneidx; for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, highest_zoneidx, ac->nodemask) { if (last_pgdat != zone->zone_pgdat) wakeup_kswapd(zone, gfp_mask, order, highest_zoneidx); last_pgdat = zone->zone_pgdat; } } static inline unsigned int gfp_to_alloc_flags(gfp_t gfp_mask) { unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET; /* * __GFP_HIGH is assumed to be the same as ALLOC_HIGH * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD * to save two branches. */ BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH); BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD); /* * The caller may dip into page reserves a bit more if the caller * cannot run direct reclaim, or if the caller has realtime scheduling * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH). */ alloc_flags |= (__force int) (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM)); if (gfp_mask & __GFP_ATOMIC) { /* * Not worth trying to allocate harder for __GFP_NOMEMALLOC even * if it can't schedule. */ if (!(gfp_mask & __GFP_NOMEMALLOC)) alloc_flags |= ALLOC_HARDER; /* * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the * comment for __cpuset_node_allowed(). */ alloc_flags &= ~ALLOC_CPUSET; } else if (unlikely(rt_task(current)) && !in_interrupt()) alloc_flags |= ALLOC_HARDER; alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, alloc_flags); return alloc_flags; } static bool oom_reserves_allowed(struct task_struct *tsk) { if (!tsk_is_oom_victim(tsk)) return false; /* * !MMU doesn't have oom reaper so give access to memory reserves * only to the thread with TIF_MEMDIE set */ if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE)) return false; return true; } /* * Distinguish requests which really need access to full memory * reserves from oom victims which can live with a portion of it */ static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask) { if (unlikely(gfp_mask & __GFP_NOMEMALLOC)) return 0; if (gfp_mask & __GFP_MEMALLOC) return ALLOC_NO_WATERMARKS; if (in_serving_softirq() && (current->flags & PF_MEMALLOC)) return ALLOC_NO_WATERMARKS; if (!in_interrupt()) { if (current->flags & PF_MEMALLOC) return ALLOC_NO_WATERMARKS; else if (oom_reserves_allowed(current)) return ALLOC_OOM; } return 0; } bool gfp_pfmemalloc_allowed(gfp_t gfp_mask) { return !!__gfp_pfmemalloc_flags(gfp_mask); } /* * Checks whether it makes sense to retry the reclaim to make a forward progress * for the given allocation request. * * We give up when we either have tried MAX_RECLAIM_RETRIES in a row * without success, or when we couldn't even meet the watermark if we * reclaimed all remaining pages on the LRU lists. * * Returns true if a retry is viable or false to enter the oom path. */ static inline bool should_reclaim_retry(gfp_t gfp_mask, unsigned order, struct alloc_context *ac, int alloc_flags, bool did_some_progress, int *no_progress_loops) { struct zone *zone; struct zoneref *z; bool ret = false; /* * Costly allocations might have made a progress but this doesn't mean * their order will become available due to high fragmentation so * always increment the no progress counter for them */ if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER) *no_progress_loops = 0; else (*no_progress_loops)++; /* * Make sure we converge to OOM if we cannot make any progress * several times in the row. */ if (*no_progress_loops > MAX_RECLAIM_RETRIES) { /* Before OOM, exhaust highatomic_reserve */ return unreserve_highatomic_pageblock(ac, true); } /* * Keep reclaiming pages while there is a chance this will lead * somewhere. If none of the target zones can satisfy our allocation * request even if all reclaimable pages are considered then we are * screwed and have to go OOM. */ for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->highest_zoneidx, ac->nodemask) { unsigned long available; unsigned long reclaimable; unsigned long min_wmark = min_wmark_pages(zone); bool wmark; available = reclaimable = zone_reclaimable_pages(zone); available += zone_page_state_snapshot(zone, NR_FREE_PAGES); /* * Would the allocation succeed if we reclaimed all * reclaimable pages? */ wmark = __zone_watermark_ok(zone, order, min_wmark, ac->highest_zoneidx, alloc_flags, available); trace_reclaim_retry_zone(z, order, reclaimable, available, min_wmark, *no_progress_loops, wmark); if (wmark) { /* * If we didn't make any progress and have a lot of * dirty + writeback pages then we should wait for * an IO to complete to slow down the reclaim and * prevent from pre mature OOM */ if (!did_some_progress) { unsigned long write_pending; write_pending = zone_page_state_snapshot(zone, NR_ZONE_WRITE_PENDING); if (2 * write_pending > reclaimable) { congestion_wait(BLK_RW_ASYNC, HZ/10); return true; } } ret = true; goto out; } } out: /* * Memory allocation/reclaim might be called from a WQ context and the * current implementation of the WQ concurrency control doesn't * recognize that a particular WQ is congested if the worker thread is * looping without ever sleeping. Therefore we have to do a short sleep * here rather than calling cond_resched(). */ if (current->flags & PF_WQ_WORKER) schedule_timeout_uninterruptible(1); else cond_resched(); return ret; } static inline bool check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac) { /* * It's possible that cpuset's mems_allowed and the nodemask from * mempolicy don't intersect. This should be normally dealt with by * policy_nodemask(), but it's possible to race with cpuset update in * such a way the check therein was true, and then it became false * before we got our cpuset_mems_cookie here. * This assumes that for all allocations, ac->nodemask can come only * from MPOL_BIND mempolicy (whose documented semantics is to be ignored * when it does not intersect with the cpuset restrictions) or the * caller can deal with a violated nodemask. */ if (cpusets_enabled() && ac->nodemask && !cpuset_nodemask_valid_mems_allowed(ac->nodemask)) { ac->nodemask = NULL; return true; } /* * When updating a task's mems_allowed or mempolicy nodemask, it is * possible to race with parallel threads in such a way that our * allocation can fail while the mask is being updated. If we are about * to fail, check if the cpuset changed during allocation and if so, * retry. */ if (read_mems_allowed_retry(cpuset_mems_cookie)) return true; return false; } static inline struct page * __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, struct alloc_context *ac) { bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM; const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER; struct page *page = NULL; unsigned int alloc_flags; unsigned long did_some_progress; enum compact_priority compact_priority; enum compact_result compact_result; int compaction_retries; int no_progress_loops; unsigned int cpuset_mems_cookie; int reserve_flags; /* * We also sanity check to catch abuse of atomic reserves being used by * callers that are not in atomic context. */ if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) == (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM))) gfp_mask &= ~__GFP_ATOMIC; retry_cpuset: compaction_retries = 0; no_progress_loops = 0; compact_priority = DEF_COMPACT_PRIORITY; cpuset_mems_cookie = read_mems_allowed_begin(); /* * The fast path uses conservative alloc_flags to succeed only until * kswapd needs to be woken up, and to avoid the cost of setting up * alloc_flags precisely. So we do that now. */ alloc_flags = gfp_to_alloc_flags(gfp_mask); /* * We need to recalculate the starting point for the zonelist iterator * because we might have used different nodemask in the fast path, or * there was a cpuset modification and we are retrying - otherwise we * could end up iterating over non-eligible zones endlessly. */ ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, ac->highest_zoneidx, ac->nodemask); if (!ac->preferred_zoneref->zone) goto nopage; if (alloc_flags & ALLOC_KSWAPD) wake_all_kswapds(order, gfp_mask, ac); /* * The adjusted alloc_flags might result in immediate success, so try * that first */ page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); if (page) goto got_pg; /* * For costly allocations, try direct compaction first, as it's likely * that we have enough base pages and don't need to reclaim. For non- * movable high-order allocations, do that as well, as compaction will * try prevent permanent fragmentation by migrating from blocks of the * same migratetype. * Don't try this for allocations that are allowed to ignore * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen. */ if (can_direct_reclaim && (costly_order || (order > 0 && ac->migratetype != MIGRATE_MOVABLE)) && !gfp_pfmemalloc_allowed(gfp_mask)) { page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, INIT_COMPACT_PRIORITY, &compact_result); if (page) goto got_pg; /* * Checks for costly allocations with __GFP_NORETRY, which * includes some THP page fault allocations */ if (costly_order && (gfp_mask & __GFP_NORETRY)) { /* * If allocating entire pageblock(s) and compaction * failed because all zones are below low watermarks * or is prohibited because it recently failed at this * order, fail immediately unless the allocator has * requested compaction and reclaim retry. * * Reclaim is * - potentially very expensive because zones are far * below their low watermarks or this is part of very * bursty high order allocations, * - not guaranteed to help because isolate_freepages() * may not iterate over freed pages as part of its * linear scan, and * - unlikely to make entire pageblocks free on its * own. */ if (compact_result == COMPACT_SKIPPED || compact_result == COMPACT_DEFERRED) goto nopage; /* * Looks like reclaim/compaction is worth trying, but * sync compaction could be very expensive, so keep * using async compaction. */ compact_priority = INIT_COMPACT_PRIORITY; } } retry: /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */ if (alloc_flags & ALLOC_KSWAPD) wake_all_kswapds(order, gfp_mask, ac); reserve_flags = __gfp_pfmemalloc_flags(gfp_mask); if (reserve_flags) alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags); /* * Reset the nodemask and zonelist iterators if memory policies can be * ignored. These allocations are high priority and system rather than * user oriented. */ if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) { ac->nodemask = NULL; ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, ac->highest_zoneidx, ac->nodemask); } /* Attempt with potentially adjusted zonelist and alloc_flags */ page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac); if (page) goto got_pg; /* Caller is not willing to reclaim, we can't balance anything */ if (!can_direct_reclaim) goto nopage; /* Avoid recursion of direct reclaim */ if (current->flags & PF_MEMALLOC) goto nopage; /* Try direct reclaim and then allocating */ page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac, &did_some_progress); if (page) goto got_pg; /* Try direct compaction and then allocating */ page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, compact_priority, &compact_result); if (page) goto got_pg; /* Do not loop if specifically requested */ if (gfp_mask & __GFP_NORETRY) goto nopage; /* * Do not retry costly high order allocations unless they are * __GFP_RETRY_MAYFAIL */ if (costly_order && !(gfp_mask & __GFP_RETRY_MAYFAIL)) goto nopage; if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags, did_some_progress > 0, &no_progress_loops)) goto retry; /* * It doesn't make any sense to retry for the compaction if the order-0 * reclaim is not able to make any progress because the current * implementation of the compaction depends on the sufficient amount * of free memory (see __compaction_suitable) */ if (did_some_progress > 0 && should_compact_retry(ac, order, alloc_flags, compact_result, &compact_priority, &compaction_retries)) goto retry; /* Deal with possible cpuset update races before we start OOM killing */ if (check_retry_cpuset(cpuset_mems_cookie, ac)) goto retry_cpuset; /* Reclaim has failed us, start killing things */ page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress); if (page) goto got_pg; /* Avoid allocations with no watermarks from looping endlessly */ if (tsk_is_oom_victim(current) && (alloc_flags & ALLOC_OOM || (gfp_mask & __GFP_NOMEMALLOC))) goto nopage; /* Retry as long as the OOM killer is making progress */ if (did_some_progress) { no_progress_loops = 0; goto retry; } nopage: /* Deal with possible cpuset update races before we fail */ if (check_retry_cpuset(cpuset_mems_cookie, ac)) goto retry_cpuset; /* * Make sure that __GFP_NOFAIL request doesn't leak out and make sure * we always retry */ if (gfp_mask & __GFP_NOFAIL) { /* * All existing users of the __GFP_NOFAIL are blockable, so warn * of any new users that actually require GFP_NOWAIT */ if (WARN_ON_ONCE(!can_direct_reclaim)) goto fail; /* * PF_MEMALLOC request from this context is rather bizarre * because we cannot reclaim anything and only can loop waiting * for somebody to do a work for us */ WARN_ON_ONCE(current->flags & PF_MEMALLOC); /* * non failing costly orders are a hard requirement which we * are not prepared for much so let's warn about these users * so that we can identify them and convert them to something * else. */ WARN_ON_ONCE(order > PAGE_ALLOC_COSTLY_ORDER); /* * Help non-failing allocations by giving them access to memory * reserves but do not use ALLOC_NO_WATERMARKS because this * could deplete whole memory reserves which would just make * the situation worse */ page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_HARDER, ac); if (page) goto got_pg; cond_resched(); goto retry; } fail: warn_alloc(gfp_mask, ac->nodemask, "page allocation failure: order:%u", order); got_pg: return page; } static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, int preferred_nid, nodemask_t *nodemask, struct alloc_context *ac, gfp_t *alloc_gfp, unsigned int *alloc_flags) { ac->highest_zoneidx = gfp_zone(gfp_mask); ac->zonelist = node_zonelist(preferred_nid, gfp_mask); ac->nodemask = nodemask; ac->migratetype = gfp_migratetype(gfp_mask); if (cpusets_enabled()) { *alloc_gfp |= __GFP_HARDWALL; /* * When we are in the interrupt context, it is irrelevant * to the current task context. It means that any node ok. */ if (!in_interrupt() && !ac->nodemask) ac->nodemask = &cpuset_current_mems_allowed; else *alloc_flags |= ALLOC_CPUSET; } fs_reclaim_acquire(gfp_mask); fs_reclaim_release(gfp_mask); might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM); if (should_fail_alloc_page(gfp_mask, order)) return false; *alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, *alloc_flags); /* Dirty zone balancing only done in the fast path */ ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE); /* * The preferred zone is used for statistics but crucially it is * also used as the starting point for the zonelist iterator. It * may get reset for allocations that ignore memory policies. */ ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, ac->highest_zoneidx, ac->nodemask); return true; } /* * __alloc_pages_bulk - Allocate a number of order-0 pages to a list or array * @gfp: GFP flags for the allocation * @preferred_nid: The preferred NUMA node ID to allocate from * @nodemask: Set of nodes to allocate from, may be NULL * @nr_pages: The number of pages desired on the list or array * @page_list: Optional list to store the allocated pages * @page_array: Optional array to store the pages * * This is a batched version of the page allocator that attempts to * allocate nr_pages quickly. Pages are added to page_list if page_list * is not NULL, otherwise it is assumed that the page_array is valid. * * For lists, nr_pages is the number of pages that should be allocated. * * For arrays, only NULL elements are populated with pages and nr_pages * is the maximum number of pages that will be stored in the array. * * Returns the number of pages on the list or array. */ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, nodemask_t *nodemask, int nr_pages, struct list_head *page_list, struct page **page_array) { struct page *page; unsigned long flags; struct zone *zone; struct zoneref *z; struct per_cpu_pages *pcp; struct list_head *pcp_list; struct alloc_context ac; gfp_t alloc_gfp; unsigned int alloc_flags = ALLOC_WMARK_LOW; int nr_populated = 0; if (unlikely(nr_pages <= 0)) return 0; /* * Skip populated array elements to determine if any pages need * to be allocated before disabling IRQs. */ while (page_array && page_array[nr_populated] && nr_populated < nr_pages) nr_populated++; /* Use the single page allocator for one page. */ if (nr_pages - nr_populated == 1) goto failed; /* May set ALLOC_NOFRAGMENT, fragmentation will return 1 page. */ gfp &= gfp_allowed_mask; alloc_gfp = gfp; if (!prepare_alloc_pages(gfp, 0, preferred_nid, nodemask, &ac, &alloc_gfp, &alloc_flags)) return 0; gfp = alloc_gfp; /* Find an allowed local zone that meets the low watermark. */ for_each_zone_zonelist_nodemask(zone, z, ac.zonelist, ac.highest_zoneidx, ac.nodemask) { unsigned long mark; if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) && !__cpuset_zone_allowed(zone, gfp)) { continue; } if (nr_online_nodes > 1 && zone != ac.preferred_zoneref->zone && zone_to_nid(zone) != zone_to_nid(ac.preferred_zoneref->zone)) { goto failed; } mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK) + nr_pages; if (zone_watermark_fast(zone, 0, mark, zonelist_zone_idx(ac.preferred_zoneref), alloc_flags, gfp)) { break; } } /* * If there are no allowed local zones that meets the watermarks then * try to allocate a single page and reclaim if necessary. */ if (unlikely(!zone)) goto failed; /* Attempt the batch allocation */ local_irq_save(flags); pcp = &this_cpu_ptr(zone->pageset)->pcp; pcp_list = &pcp->lists[ac.migratetype]; while (nr_populated < nr_pages) { /* Skip existing pages */ if (page_array && page_array[nr_populated]) { nr_populated++; continue; } page = __rmqueue_pcplist(zone, ac.migratetype, alloc_flags, pcp, pcp_list); if (unlikely(!page)) { /* Try and get at least one page */ if (!nr_populated) goto failed_irq; break; } /* * Ideally this would be batched but the best way to do * that cheaply is to first convert zone_statistics to * be inaccurate per-cpu counter like vm_events to avoid * a RMW cycle then do the accounting with IRQs enabled. */ __count_zid_vm_events(PGALLOC, zone_idx(zone), 1); zone_statistics(ac.preferred_zoneref->zone, zone); prep_new_page(page, 0, gfp, 0); if (page_list) list_add(&page->lru, page_list); else page_array[nr_populated] = page; nr_populated++; } local_irq_restore(flags); return nr_populated; failed_irq: local_irq_restore(flags); failed: page = __alloc_pages(gfp, 0, preferred_nid, nodemask); if (page) { if (page_list) list_add(&page->lru, page_list); else page_array[nr_populated] = page; nr_populated++; } return nr_populated; } EXPORT_SYMBOL_GPL(__alloc_pages_bulk); /* * This is the 'heart' of the zoned buddy allocator. */ struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid, nodemask_t *nodemask) { struct page *page; unsigned int alloc_flags = ALLOC_WMARK_LOW; gfp_t alloc_gfp; /* The gfp_t that was actually used for allocation */ struct alloc_context ac = { }; /* * There are several places where we assume that the order value is sane * so bail out early if the request is out of bound. */ if (unlikely(order >= MAX_ORDER)) { WARN_ON_ONCE(!(gfp & __GFP_NOWARN)); return NULL; } gfp &= gfp_allowed_mask; /* * Apply scoped allocation constraints. This is mainly about GFP_NOFS * resp. GFP_NOIO which has to be inherited for all allocation requests * from a particular context which has been marked by * memalloc_no{fs,io}_{save,restore}. And PF_MEMALLOC_PIN which ensures * movable zones are not used during allocation. */ gfp = current_gfp_context(gfp); alloc_gfp = gfp; if (!prepare_alloc_pages(gfp, order, preferred_nid, nodemask, &ac, &alloc_gfp, &alloc_flags)) return NULL; /* * Forbid the first pass from falling back to types that fragment * memory until all local zones are considered. */ alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp); /* First allocation attempt */ page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac); if (likely(page)) goto out; alloc_gfp = gfp; ac.spread_dirty_pages = false; /* * Restore the original nodemask if it was potentially replaced with * &cpuset_current_mems_allowed to optimize the fast-path attempt. */ ac.nodemask = nodemask; page = __alloc_pages_slowpath(alloc_gfp, order, &ac); out: if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT) && page && unlikely(__memcg_kmem_charge_page(page, gfp, order) != 0)) { __free_pages(page, order); page = NULL; } trace_mm_page_alloc(page, order, alloc_gfp, ac.migratetype); return page; } EXPORT_SYMBOL(__alloc_pages); /* * Common helper functions. Never use with __GFP_HIGHMEM because the returned * address cannot represent highmem pages. Use alloc_pages and then kmap if * you need to access high mem. */ unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order) { struct page *page; page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, order); if (!page) return 0; return (unsigned long) page_address(page); } EXPORT_SYMBOL(__get_free_pages); unsigned long get_zeroed_page(gfp_t gfp_mask) { return __get_free_pages(gfp_mask | __GFP_ZERO, 0); } EXPORT_SYMBOL(get_zeroed_page); static inline void free_the_page(struct page *page, unsigned int order) { if (order == 0) /* Via pcp? */ free_unref_page(page); else __free_pages_ok(page, order, FPI_NONE); } /** * __free_pages - Free pages allocated with alloc_pages(). * @page: The page pointer returned from alloc_pages(). * @order: The order of the allocation. * * This function can free multi-page allocations that are not compound * pages. It does not check that the @order passed in matches that of * the allocation, so it is easy to leak memory. Freeing more memory * than was allocated will probably emit a warning. * * If the last reference to this page is speculative, it will be released * by put_page() which only frees the first page of a non-compound * allocation. To prevent the remaining pages from being leaked, we free * the subsequent pages here. If you want to use the page's reference * count to decide when to free the allocation, you should allocate a * compound page, and use put_page() instead of __free_pages(). * * Context: May be called in interrupt context or while holding a normal * spinlock, but not in NMI context or while holding a raw spinlock. */ void __free_pages(struct page *page, unsigned int order) { if (put_page_testzero(page)) free_the_page(page, order); else if (!PageHead(page)) while (order-- > 0) free_the_page(page + (1 << order), order); } EXPORT_SYMBOL(__free_pages); void free_pages(unsigned long addr, unsigned int order) { if (addr != 0) { VM_BUG_ON(!virt_addr_valid((void *)addr)); __free_pages(virt_to_page((void *)addr), order); } } EXPORT_SYMBOL(free_pages); /* * Page Fragment: * An arbitrary-length arbitrary-offset area of memory which resides * within a 0 or higher order page. Multiple fragments within that page * are individually refcounted, in the page's reference counter. * * The page_frag functions below provide a simple allocation framework for * page fragments. This is used by the network stack and network device * drivers to provide a backing region of memory for use as either an * sk_buff->head, or to be used in the "frags" portion of skb_shared_info. */ static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, gfp_t gfp_mask) { struct page *page = NULL; gfp_t gfp = gfp_mask; #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC; page = alloc_pages_node(NUMA_NO_NODE, gfp_mask, PAGE_FRAG_CACHE_MAX_ORDER); nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE; #endif if (unlikely(!page)) page = alloc_pages_node(NUMA_NO_NODE, gfp, 0); nc->va = page ? page_address(page) : NULL; return page; } void __page_frag_cache_drain(struct page *page, unsigned int count) { VM_BUG_ON_PAGE(page_ref_count(page) == 0, page); if (page_ref_sub_and_test(page, count)) free_the_page(page, compound_order(page)); } EXPORT_SYMBOL(__page_frag_cache_drain); void *page_frag_alloc_align(struct page_frag_cache *nc, unsigned int fragsz, gfp_t gfp_mask, unsigned int align_mask) { unsigned int size = PAGE_SIZE; struct page *page; int offset; if (unlikely(!nc->va)) { refill: page = __page_frag_cache_refill(nc, gfp_mask); if (!page) return NULL; #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) /* if size can vary use size else just use PAGE_SIZE */ size = nc->size; #endif /* Even if we own the page, we do not use atomic_set(). * This would break get_page_unless_zero() users. */ page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE); /* reset page count bias and offset to start of new frag */ nc->pfmemalloc = page_is_pfmemalloc(page); nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; nc->offset = size; } offset = nc->offset - fragsz; if (unlikely(offset < 0)) { page = virt_to_page(nc->va); if (!page_ref_sub_and_test(page, nc->pagecnt_bias)) goto refill; if (unlikely(nc->pfmemalloc)) { free_the_page(page, compound_order(page)); goto refill; } #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) /* if size can vary use size else just use PAGE_SIZE */ size = nc->size; #endif /* OK, page count is 0, we can safely set it */ set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1); /* reset page count bias and offset to start of new frag */ nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; offset = size - fragsz; } nc->pagecnt_bias--; offset &= align_mask; nc->offset = offset; return nc->va + offset; } EXPORT_SYMBOL(page_frag_alloc_align); /* * Frees a page fragment allocated out of either a compound or order 0 page. */ void page_frag_free(void *addr) { struct page *page = virt_to_head_page(addr); if (unlikely(put_page_testzero(page))) free_the_page(page, compound_order(page)); } EXPORT_SYMBOL(page_frag_free); static void *make_alloc_exact(unsigned long addr, unsigned int order, size_t size) { if (addr) { unsigned long alloc_end = addr + (PAGE_SIZE << order); unsigned long used = addr + PAGE_ALIGN(size); split_page(virt_to_page((void *)addr), order); while (used < alloc_end) { free_page(used); used += PAGE_SIZE; } } return (void *)addr; } /** * alloc_pages_exact - allocate an exact number physically-contiguous pages. * @size: the number of bytes to allocate * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP * * This function is similar to alloc_pages(), except that it allocates the * minimum number of pages to satisfy the request. alloc_pages() can only * allocate memory in power-of-two pages. * * This function is also limited by MAX_ORDER. * * Memory allocated by this function must be released by free_pages_exact(). * * Return: pointer to the allocated area or %NULL in case of error. */ void *alloc_pages_exact(size_t size, gfp_t gfp_mask) { unsigned int order = get_order(size); unsigned long addr; if (WARN_ON_ONCE(gfp_mask & __GFP_COMP)) gfp_mask &= ~__GFP_COMP; addr = __get_free_pages(gfp_mask, order); return make_alloc_exact(addr, order, size); } EXPORT_SYMBOL(alloc_pages_exact); /** * alloc_pages_exact_nid - allocate an exact number of physically-contiguous * pages on a node. * @nid: the preferred node ID where memory should be allocated * @size: the number of bytes to allocate * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP * * Like alloc_pages_exact(), but try to allocate on node nid first before falling * back. * * Return: pointer to the allocated area or %NULL in case of error. */ void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask) { unsigned int order = get_order(size); struct page *p; if (WARN_ON_ONCE(gfp_mask & __GFP_COMP)) gfp_mask &= ~__GFP_COMP; p = alloc_pages_node(nid, gfp_mask, order); if (!p) return NULL; return make_alloc_exact((unsigned long)page_address(p), order, size); } /** * free_pages_exact - release memory allocated via alloc_pages_exact() * @virt: the value returned by alloc_pages_exact. * @size: size of allocation, same value as passed to alloc_pages_exact(). * * Release the memory allocated by a previous call to alloc_pages_exact. */ void free_pages_exact(void *virt, size_t size) { unsigned long addr = (unsigned long)virt; unsigned long end = addr + PAGE_ALIGN(size); while (addr < end) { free_page(addr); addr += PAGE_SIZE; } } EXPORT_SYMBOL(free_pages_exact); /** * nr_free_zone_pages - count number of pages beyond high watermark * @offset: The zone index of the highest zone * * nr_free_zone_pages() counts the number of pages which are beyond the * high watermark within all zones at or below a given zone index. For each * zone, the number of pages is calculated as: * * nr_free_zone_pages = managed_pages - high_pages * * Return: number of pages beyond high watermark. */ static unsigned long nr_free_zone_pages(int offset) { struct zoneref *z; struct zone *zone; /* Just pick one node, since fallback list is circular */ unsigned long sum = 0; struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL); for_each_zone_zonelist(zone, z, zonelist, offset) { unsigned long size = zone_managed_pages(zone); unsigned long high = high_wmark_pages(zone); if (size > high) sum += size - high; } return sum; } /** * nr_free_buffer_pages - count number of pages beyond high watermark * * nr_free_buffer_pages() counts the number of pages which are beyond the high * watermark within ZONE_DMA and ZONE_NORMAL. * * Return: number of pages beyond high watermark within ZONE_DMA and * ZONE_NORMAL. */ unsigned long nr_free_buffer_pages(void) { return nr_free_zone_pages(gfp_zone(GFP_USER)); } EXPORT_SYMBOL_GPL(nr_free_buffer_pages); static inline void show_node(struct zone *zone) { if (IS_ENABLED(CONFIG_NUMA)) printk("Node %d ", zone_to_nid(zone)); } long si_mem_available(void) { long available; unsigned long pagecache; unsigned long wmark_low = 0; unsigned long pages[NR_LRU_LISTS]; unsigned long reclaimable; struct zone *zone; int lru; for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++) pages[lru] = global_node_page_state(NR_LRU_BASE + lru); for_each_zone(zone) wmark_low += low_wmark_pages(zone); /* * Estimate the amount of memory available for userspace allocations, * without causing swapping. */ available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages; /* * Not all the page cache can be freed, otherwise the system will * start swapping. Assume at least half of the page cache, or the * low watermark worth of cache, needs to stay. */ pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE]; pagecache -= min(pagecache / 2, wmark_low); available += pagecache; /* * Part of the reclaimable slab and other kernel memory consists of * items that are in use, and cannot be freed. Cap this estimate at the * low watermark. */ reclaimable = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B) + global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE); available += reclaimable - min(reclaimable / 2, wmark_low); if (available < 0) available = 0; return available; } EXPORT_SYMBOL_GPL(si_mem_available); void si_meminfo(struct sysinfo *val) { val->totalram = totalram_pages(); val->sharedram = global_node_page_state(NR_SHMEM); val->freeram = global_zone_page_state(NR_FREE_PAGES); val->bufferram = nr_blockdev_pages(); val->totalhigh = totalhigh_pages(); val->freehigh = nr_free_highpages(); val->mem_unit = PAGE_SIZE; } EXPORT_SYMBOL(si_meminfo); #ifdef CONFIG_NUMA void si_meminfo_node(struct sysinfo *val, int nid) { int zone_type; /* needs to be signed */ unsigned long managed_pages = 0; unsigned long managed_highpages = 0; unsigned long free_highpages = 0; pg_data_t *pgdat = NODE_DATA(nid); for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]); val->totalram = managed_pages; val->sharedram = node_page_state(pgdat, NR_SHMEM); val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES); #ifdef CONFIG_HIGHMEM for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) { struct zone *zone = &pgdat->node_zones[zone_type]; if (is_highmem(zone)) { managed_highpages += zone_managed_pages(zone); free_highpages += zone_page_state(zone, NR_FREE_PAGES); } } val->totalhigh = managed_highpages; val->freehigh = free_highpages; #else val->totalhigh = managed_highpages; val->freehigh = free_highpages; #endif val->mem_unit = PAGE_SIZE; } #endif /* * Determine whether the node should be displayed or not, depending on whether * SHOW_MEM_FILTER_NODES was passed to show_free_areas(). */ static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask) { if (!(flags & SHOW_MEM_FILTER_NODES)) return false; /* * no node mask - aka implicit memory numa policy. Do not bother with * the synchronization - read_mems_allowed_begin - because we do not * have to be precise here. */ if (!nodemask) nodemask = &cpuset_current_mems_allowed; return !node_isset(nid, *nodemask); } #define K(x) ((x) << (PAGE_SHIFT-10)) static void show_migration_types(unsigned char type) { static const char types[MIGRATE_TYPES] = { [MIGRATE_UNMOVABLE] = 'U', [MIGRATE_MOVABLE] = 'M', [MIGRATE_RECLAIMABLE] = 'E', [MIGRATE_HIGHATOMIC] = 'H', #ifdef CONFIG_CMA [MIGRATE_CMA] = 'C', #endif #ifdef CONFIG_MEMORY_ISOLATION [MIGRATE_ISOLATE] = 'I', #endif }; char tmp[MIGRATE_TYPES + 1]; char *p = tmp; int i; for (i = 0; i < MIGRATE_TYPES; i++) { if (type & (1 << i)) *p++ = types[i]; } *p = '\0'; printk(KERN_CONT "(%s) ", tmp); } /* * Show free area list (used inside shift_scroll-lock stuff) * We also calculate the percentage fragmentation. We do this by counting the * memory on each free list with the exception of the first item on the list. * * Bits in @filter: * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's * cpuset. */ void show_free_areas(unsigned int filter, nodemask_t *nodemask) { unsigned long free_pcp = 0; int cpu; struct zone *zone; pg_data_t *pgdat; for_each_populated_zone(zone) { if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask)) continue; for_each_online_cpu(cpu) free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count; } printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n" " active_file:%lu inactive_file:%lu isolated_file:%lu\n" " unevictable:%lu dirty:%lu writeback:%lu\n" " slab_reclaimable:%lu slab_unreclaimable:%lu\n" " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n" " free:%lu free_pcp:%lu free_cma:%lu\n", global_node_page_state(NR_ACTIVE_ANON), global_node_page_state(NR_INACTIVE_ANON), global_node_page_state(NR_ISOLATED_ANON), global_node_page_state(NR_ACTIVE_FILE), global_node_page_state(NR_INACTIVE_FILE), global_node_page_state(NR_ISOLATED_FILE), global_node_page_state(NR_UNEVICTABLE), global_node_page_state(NR_FILE_DIRTY), global_node_page_state(NR_WRITEBACK), global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B), global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B), global_node_page_state(NR_FILE_MAPPED), global_node_page_state(NR_SHMEM), global_node_page_state(NR_PAGETABLE), global_zone_page_state(NR_BOUNCE), global_zone_page_state(NR_FREE_PAGES), free_pcp, global_zone_page_state(NR_FREE_CMA_PAGES)); for_each_online_pgdat(pgdat) { if (show_mem_node_skip(filter, pgdat->node_id, nodemask)) continue; printk("Node %d" " active_anon:%lukB" " inactive_anon:%lukB" " active_file:%lukB" " inactive_file:%lukB" " unevictable:%lukB" " isolated(anon):%lukB" " isolated(file):%lukB" " mapped:%lukB" " dirty:%lukB" " writeback:%lukB" " shmem:%lukB" #ifdef CONFIG_TRANSPARENT_HUGEPAGE " shmem_thp: %lukB" " shmem_pmdmapped: %lukB" " anon_thp: %lukB" #endif " writeback_tmp:%lukB" " kernel_stack:%lukB" #ifdef CONFIG_SHADOW_CALL_STACK " shadow_call_stack:%lukB" #endif " pagetables:%lukB" " all_unreclaimable? %s" "\n", pgdat->node_id, K(node_page_state(pgdat, NR_ACTIVE_ANON)), K(node_page_state(pgdat, NR_INACTIVE_ANON)), K(node_page_state(pgdat, NR_ACTIVE_FILE)), K(node_page_state(pgdat, NR_INACTIVE_FILE)), K(node_page_state(pgdat, NR_UNEVICTABLE)), K(node_page_state(pgdat, NR_ISOLATED_ANON)), K(node_page_state(pgdat, NR_ISOLATED_FILE)), K(node_page_state(pgdat, NR_FILE_MAPPED)), K(node_page_state(pgdat, NR_FILE_DIRTY)), K(node_page_state(pgdat, NR_WRITEBACK)), K(node_page_state(pgdat, NR_SHMEM)), #ifdef CONFIG_TRANSPARENT_HUGEPAGE K(node_page_state(pgdat, NR_SHMEM_THPS)), K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)), K(node_page_state(pgdat, NR_ANON_THPS)), #endif K(node_page_state(pgdat, NR_WRITEBACK_TEMP)), node_page_state(pgdat, NR_KERNEL_STACK_KB), #ifdef CONFIG_SHADOW_CALL_STACK node_page_state(pgdat, NR_KERNEL_SCS_KB), #endif K(node_page_state(pgdat, NR_PAGETABLE)), pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ? "yes" : "no"); } for_each_populated_zone(zone) { int i; if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask)) continue; free_pcp = 0; for_each_online_cpu(cpu) free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count; show_node(zone); printk(KERN_CONT "%s" " free:%lukB" " min:%lukB" " low:%lukB" " high:%lukB" " reserved_highatomic:%luKB" " active_anon:%lukB" " inactive_anon:%lukB" " active_file:%lukB" " inactive_file:%lukB" " unevictable:%lukB" " writepending:%lukB" " present:%lukB" " managed:%lukB" " mlocked:%lukB" " bounce:%lukB" " free_pcp:%lukB" " local_pcp:%ukB" " free_cma:%lukB" "\n", zone->name, K(zone_page_state(zone, NR_FREE_PAGES)), K(min_wmark_pages(zone)), K(low_wmark_pages(zone)), K(high_wmark_pages(zone)), K(zone->nr_reserved_highatomic), K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)), K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)), K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)), K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)), K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)), K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)), K(zone->present_pages), K(zone_managed_pages(zone)), K(zone_page_state(zone, NR_MLOCK)), K(zone_page_state(zone, NR_BOUNCE)), K(free_pcp), K(this_cpu_read(zone->pageset->pcp.count)), K(zone_page_state(zone, NR_FREE_CMA_PAGES))); printk("lowmem_reserve[]:"); for (i = 0; i < MAX_NR_ZONES; i++) printk(KERN_CONT " %ld", zone->lowmem_reserve[i]); printk(KERN_CONT "\n"); } for_each_populated_zone(zone) { unsigned int order; unsigned long nr[MAX_ORDER], flags, total = 0; unsigned char types[MAX_ORDER]; if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask)) continue; show_node(zone); printk(KERN_CONT "%s: ", zone->name); spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { struct free_area *area = &zone->free_area[order]; int type; nr[order] = area->nr_free; total += nr[order] << order; types[order] = 0; for (type = 0; type < MIGRATE_TYPES; type++) { if (!free_area_empty(area, type)) types[order] |= 1 << type; } } spin_unlock_irqrestore(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { printk(KERN_CONT "%lu*%lukB ", nr[order], K(1UL) << order); if (nr[order]) show_migration_types(types[order]); } printk(KERN_CONT "= %lukB\n", K(total)); } hugetlb_show_meminfo(); printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES)); show_swap_cache_info(); } static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref) { zoneref->zone = zone; zoneref->zone_idx = zone_idx(zone); } /* * Builds allocation fallback zone lists. * * Add all populated zones of a node to the zonelist. */ static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs) { struct zone *zone; enum zone_type zone_type = MAX_NR_ZONES; int nr_zones = 0; do { zone_type--; zone = pgdat->node_zones + zone_type; if (managed_zone(zone)) { zoneref_set_zone(zone, &zonerefs[nr_zones++]); check_highest_zone(zone_type); } } while (zone_type); return nr_zones; } #ifdef CONFIG_NUMA static int __parse_numa_zonelist_order(char *s) { /* * We used to support different zonelists modes but they turned * out to be just not useful. Let's keep the warning in place * if somebody still use the cmd line parameter so that we do * not fail it silently */ if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) { pr_warn("Ignoring unsupported numa_zonelist_order value: %s\n", s); return -EINVAL; } return 0; } char numa_zonelist_order[] = "Node"; /* * sysctl handler for numa_zonelist_order */ int numa_zonelist_order_handler(struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { if (write) return __parse_numa_zonelist_order(buffer); return proc_dostring(table, write, buffer, length, ppos); } #define MAX_NODE_LOAD (nr_online_nodes) static int node_load[MAX_NUMNODES]; /** * find_next_best_node - find the next node that should appear in a given node's fallback list * @node: node whose fallback list we're appending * @used_node_mask: nodemask_t of already used nodes * * We use a number of factors to determine which is the next node that should * appear on a given node's fallback list. The node should not have appeared * already in @node's fallback list, and it should be the next closest node * according to the distance array (which contains arbitrary distance values * from each node to each node in the system), and should also prefer nodes * with no CPUs, since presumably they'll have very little allocation pressure * on them otherwise. * * Return: node id of the found node or %NUMA_NO_NODE if no node is found. */ static int find_next_best_node(int node, nodemask_t *used_node_mask) { int n, val; int min_val = INT_MAX; int best_node = NUMA_NO_NODE; /* Use the local node if we haven't already */ if (!node_isset(node, *used_node_mask)) { node_set(node, *used_node_mask); return node; } for_each_node_state(n, N_MEMORY) { /* Don't want a node to appear more than once */ if (node_isset(n, *used_node_mask)) continue; /* Use the distance array to find the distance */ val = node_distance(node, n); /* Penalize nodes under us ("prefer the next node") */ val += (n < node); /* Give preference to headless and unused nodes */ if (!cpumask_empty(cpumask_of_node(n))) val += PENALTY_FOR_NODE_WITH_CPUS; /* Slight preference for less loaded node */ val *= (MAX_NODE_LOAD*MAX_NUMNODES); val += node_load[n]; if (val < min_val) { min_val = val; best_node = n; } } if (best_node >= 0) node_set(best_node, *used_node_mask); return best_node; } /* * Build zonelists ordered by node and zones within node. * This results in maximum locality--normal zone overflows into local * DMA zone, if any--but risks exhausting DMA zone. */ static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, unsigned nr_nodes) { struct zoneref *zonerefs; int i; zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; for (i = 0; i < nr_nodes; i++) { int nr_zones; pg_data_t *node = NODE_DATA(node_order[i]); nr_zones = build_zonerefs_node(node, zonerefs); zonerefs += nr_zones; } zonerefs->zone = NULL; zonerefs->zone_idx = 0; } /* * Build gfp_thisnode zonelists */ static void build_thisnode_zonelists(pg_data_t *pgdat) { struct zoneref *zonerefs; int nr_zones; zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs; nr_zones = build_zonerefs_node(pgdat, zonerefs); zonerefs += nr_zones; zonerefs->zone = NULL; zonerefs->zone_idx = 0; } /* * Build zonelists ordered by zone and nodes within zones. * This results in conserving DMA zone[s] until all Normal memory is * exhausted, but results in overflowing to remote node while memory * may still exist in local DMA zone. */ static void build_zonelists(pg_data_t *pgdat) { static int node_order[MAX_NUMNODES]; int node, load, nr_nodes = 0; nodemask_t used_mask = NODE_MASK_NONE; int local_node, prev_node; /* NUMA-aware ordering of nodes */ local_node = pgdat->node_id; load = nr_online_nodes; prev_node = local_node; memset(node_order, 0, sizeof(node_order)); while ((node = find_next_best_node(local_node, &used_mask)) >= 0) { /* * We don't want to pressure a particular node. * So adding penalty to the first node in same * distance group to make it round-robin. */ if (node_distance(local_node, node) != node_distance(local_node, prev_node)) node_load[node] = load; node_order[nr_nodes++] = node; prev_node = node; load--; } build_zonelists_in_node_order(pgdat, node_order, nr_nodes); build_thisnode_zonelists(pgdat); } #ifdef CONFIG_HAVE_MEMORYLESS_NODES /* * Return node id of node used for "local" allocations. * I.e., first node id of first zone in arg node's generic zonelist. * Used for initializing percpu 'numa_mem', which is used primarily * for kernel allocations, so use GFP_KERNEL flags to locate zonelist. */ int local_memory_node(int node) { struct zoneref *z; z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL), gfp_zone(GFP_KERNEL), NULL); return zone_to_nid(z->zone); } #endif static void setup_min_unmapped_ratio(void); static void setup_min_slab_ratio(void); #else /* CONFIG_NUMA */ static void build_zonelists(pg_data_t *pgdat) { int node, local_node; struct zoneref *zonerefs; int nr_zones; local_node = pgdat->node_id; zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; nr_zones = build_zonerefs_node(pgdat, zonerefs); zonerefs += nr_zones; /* * Now we build the zonelist so that it contains the zones * of all the other nodes. * We don't want to pressure a particular node, so when * building the zones for node N, we make sure that the * zones coming right after the local ones are those from * node N+1 (modulo N) */ for (node = local_node + 1; node < MAX_NUMNODES; node++) { if (!node_online(node)) continue; nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs); zonerefs += nr_zones; } for (node = 0; node < local_node; node++) { if (!node_online(node)) continue; nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs); zonerefs += nr_zones; } zonerefs->zone = NULL; zonerefs->zone_idx = 0; } #endif /* CONFIG_NUMA */ /* * Boot pageset table. One per cpu which is going to be used for all * zones and all nodes. The parameters will be set in such a way * that an item put on a list will immediately be handed over to * the buddy list. This is safe since pageset manipulation is done * with interrupts disabled. * * The boot_pagesets must be kept even after bootup is complete for * unused processors and/or zones. They do play a role for bootstrapping * hotplugged processors. * * zoneinfo_show() and maybe other functions do * not check if the processor is online before following the pageset pointer. * Other parts of the kernel may not check if the zone is available. */ static void pageset_init(struct per_cpu_pageset *p); /* These effectively disable the pcplists in the boot pageset completely */ #define BOOT_PAGESET_HIGH 0 #define BOOT_PAGESET_BATCH 1 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset); static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats); static void __build_all_zonelists(void *data) { int nid; int __maybe_unused cpu; pg_data_t *self = data; static DEFINE_SPINLOCK(lock); spin_lock(&lock); #ifdef CONFIG_NUMA memset(node_load, 0, sizeof(node_load)); #endif /* * This node is hotadded and no memory is yet present. So just * building zonelists is fine - no need to touch other nodes. */ if (self && !node_online(self->node_id)) { build_zonelists(self); } else { for_each_online_node(nid) { pg_data_t *pgdat = NODE_DATA(nid); build_zonelists(pgdat); } #ifdef CONFIG_HAVE_MEMORYLESS_NODES /* * We now know the "local memory node" for each node-- * i.e., the node of the first zone in the generic zonelist. * Set up numa_mem percpu variable for on-line cpus. During * boot, only the boot cpu should be on-line; we'll init the * secondary cpus' numa_mem as they come on-line. During * node/memory hotplug, we'll fixup all on-line cpus. */ for_each_online_cpu(cpu) set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu))); #endif } spin_unlock(&lock); } static noinline void __init build_all_zonelists_init(void) { int cpu; __build_all_zonelists(NULL); /* * Initialize the boot_pagesets that are going to be used * for bootstrapping processors. The real pagesets for * each zone will be allocated later when the per cpu * allocator is available. * * boot_pagesets are used also for bootstrapping offline * cpus if the system is already booted because the pagesets * are needed to initialize allocators on a specific cpu too. * F.e. the percpu allocator needs the page allocator which * needs the percpu allocator in order to allocate its pagesets * (a chicken-egg dilemma). */ for_each_possible_cpu(cpu) pageset_init(&per_cpu(boot_pageset, cpu)); mminit_verify_zonelist(); cpuset_init_current_mems_allowed(); } /* * unless system_state == SYSTEM_BOOTING. * * __ref due to call of __init annotated helper build_all_zonelists_init * [protected by SYSTEM_BOOTING]. */ void __ref build_all_zonelists(pg_data_t *pgdat) { unsigned long vm_total_pages; if (system_state == SYSTEM_BOOTING) { build_all_zonelists_init(); } else { __build_all_zonelists(pgdat); /* cpuset refresh routine should be here */ } /* Get the number of free pages beyond high watermark in all zones. */ vm_total_pages = nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE)); /* * Disable grouping by mobility if the number of pages in the * system is too low to allow the mechanism to work. It would be * more accurate, but expensive to check per-zone. This check is * made on memory-hotadd so a system can start with mobility * disabled and enable it later */ if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES)) page_group_by_mobility_disabled = 1; else page_group_by_mobility_disabled = 0; pr_info("Built %u zonelists, mobility grouping %s. Total pages: %ld\n", nr_online_nodes, page_group_by_mobility_disabled ? "off" : "on", vm_total_pages); #ifdef CONFIG_NUMA pr_info("Policy zone: %s\n", zone_names[policy_zone]); #endif } /* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */ static bool __meminit overlap_memmap_init(unsigned long zone, unsigned long *pfn) { static struct memblock_region *r; if (mirrored_kernelcore && zone == ZONE_MOVABLE) { if (!r || *pfn >= memblock_region_memory_end_pfn(r)) { for_each_mem_region(r) { if (*pfn < memblock_region_memory_end_pfn(r)) break; } } if (*pfn >= memblock_region_memory_base_pfn(r) && memblock_is_mirror(r)) { *pfn = memblock_region_memory_end_pfn(r); return true; } } return false; } /* * Initially all pages are reserved - free ones are freed * up by memblock_free_all() once the early boot process is * done. Non-atomic initialization, single-pass. * * All aligned pageblocks are initialized to the specified migratetype * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related * zone stats (e.g., nr_isolate_pageblock) are touched. */ void __meminit memmap_init_range(unsigned long size, int nid, unsigned long zone, unsigned long start_pfn, unsigned long zone_end_pfn, enum meminit_context context, struct vmem_altmap *altmap, int migratetype) { unsigned long pfn, end_pfn = start_pfn + size; struct page *page; if (highest_memmap_pfn < end_pfn - 1) highest_memmap_pfn = end_pfn - 1; #ifdef CONFIG_ZONE_DEVICE /* * Honor reservation requested by the driver for this ZONE_DEVICE * memory. We limit the total number of pages to initialize to just * those that might contain the memory mapping. We will defer the * ZONE_DEVICE page initialization until after we have released * the hotplug lock. */ if (zone == ZONE_DEVICE) { if (!altmap) return; if (start_pfn == altmap->base_pfn) start_pfn += altmap->reserve; end_pfn = altmap->base_pfn + vmem_altmap_offset(altmap); } #endif for (pfn = start_pfn; pfn < end_pfn; ) { /* * There can be holes in boot-time mem_map[]s handed to this * function. They do not exist on hotplugged memory. */ if (context == MEMINIT_EARLY) { if (overlap_memmap_init(zone, &pfn)) continue; if (defer_init(nid, pfn, zone_end_pfn)) break; } page = pfn_to_page(pfn); __init_single_page(page, pfn, zone, nid); if (context == MEMINIT_HOTPLUG) __SetPageReserved(page); /* * Usually, we want to mark the pageblock MIGRATE_MOVABLE, * such that unmovable allocations won't be scattered all * over the place during system boot. */ if (IS_ALIGNED(pfn, pageblock_nr_pages)) { set_pageblock_migratetype(page, migratetype); cond_resched(); } pfn++; } } #ifdef CONFIG_ZONE_DEVICE void __ref memmap_init_zone_device(struct zone *zone, unsigned long start_pfn, unsigned long nr_pages, struct dev_pagemap *pgmap) { unsigned long pfn, end_pfn = start_pfn + nr_pages; struct pglist_data *pgdat = zone->zone_pgdat; struct vmem_altmap *altmap = pgmap_altmap(pgmap); unsigned long zone_idx = zone_idx(zone); unsigned long start = jiffies; int nid = pgdat->node_id; if (WARN_ON_ONCE(!pgmap || zone_idx(zone) != ZONE_DEVICE)) return; /* * The call to memmap_init_zone should have already taken care * of the pages reserved for the memmap, so we can just jump to * the end of that region and start processing the device pages. */ if (altmap) { start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap); nr_pages = end_pfn - start_pfn; } for (pfn = start_pfn; pfn < end_pfn; pfn++) { struct page *page = pfn_to_page(pfn); __init_single_page(page, pfn, zone_idx, nid); /* * Mark page reserved as it will need to wait for onlining * phase for it to be fully associated with a zone. * * We can use the non-atomic __set_bit operation for setting * the flag as we are still initializing the pages. */ __SetPageReserved(page); /* * ZONE_DEVICE pages union ->lru with a ->pgmap back pointer * and zone_device_data. It is a bug if a ZONE_DEVICE page is * ever freed or placed on a driver-private list. */ page->pgmap = pgmap; page->zone_device_data = NULL; /* * Mark the block movable so that blocks are reserved for * movable at startup. This will force kernel allocations * to reserve their blocks rather than leaking throughout * the address space during boot when many long-lived * kernel allocations are made. * * Please note that MEMINIT_HOTPLUG path doesn't clear memmap * because this is done early in section_activate() */ if (IS_ALIGNED(pfn, pageblock_nr_pages)) { set_pageblock_migratetype(page, MIGRATE_MOVABLE); cond_resched(); } } pr_info("%s initialised %lu pages in %ums\n", __func__, nr_pages, jiffies_to_msecs(jiffies - start)); } #endif static void __meminit zone_init_free_lists(struct zone *zone) { unsigned int order, t; for_each_migratetype_order(order, t) { INIT_LIST_HEAD(&zone->free_area[order].free_list[t]); zone->free_area[order].nr_free = 0; } } #if !defined(CONFIG_FLAT_NODE_MEM_MAP) /* * Only struct pages that correspond to ranges defined by memblock.memory * are zeroed and initialized by going through __init_single_page() during * memmap_init_zone(). * * But, there could be struct pages that correspond to holes in * memblock.memory. This can happen because of the following reasons: * - physical memory bank size is not necessarily the exact multiple of the * arbitrary section size * - early reserved memory may not be listed in memblock.memory * - memory layouts defined with memmap= kernel parameter may not align * nicely with memmap sections * * Explicitly initialize those struct pages so that: * - PG_Reserved is set * - zone and node links point to zone and node that span the page if the * hole is in the middle of a zone * - zone and node links point to adjacent zone/node if the hole falls on * the zone boundary; the pages in such holes will be prepended to the * zone/node above the hole except for the trailing pages in the last * section that will be appended to the zone/node below. */ static u64 __meminit init_unavailable_range(unsigned long spfn, unsigned long epfn, int zone, int node) { unsigned long pfn; u64 pgcnt = 0; for (pfn = spfn; pfn < epfn; pfn++) { if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) { pfn = ALIGN_DOWN(pfn, pageblock_nr_pages) + pageblock_nr_pages - 1; continue; } __init_single_page(pfn_to_page(pfn), pfn, zone, node); __SetPageReserved(pfn_to_page(pfn)); pgcnt++; } return pgcnt; } #else static inline u64 init_unavailable_range(unsigned long spfn, unsigned long epfn, int zone, int node) { return 0; } #endif void __meminit __weak memmap_init_zone(struct zone *zone) { unsigned long zone_start_pfn = zone->zone_start_pfn; unsigned long zone_end_pfn = zone_start_pfn + zone->spanned_pages; int i, nid = zone_to_nid(zone), zone_id = zone_idx(zone); static unsigned long hole_pfn; unsigned long start_pfn, end_pfn; u64 pgcnt = 0; for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) { start_pfn = clamp(start_pfn, zone_start_pfn, zone_end_pfn); end_pfn = clamp(end_pfn, zone_start_pfn, zone_end_pfn); if (end_pfn > start_pfn) memmap_init_range(end_pfn - start_pfn, nid, zone_id, start_pfn, zone_end_pfn, MEMINIT_EARLY, NULL, MIGRATE_MOVABLE); if (hole_pfn < start_pfn) pgcnt += init_unavailable_range(hole_pfn, start_pfn, zone_id, nid); hole_pfn = end_pfn; } #ifdef CONFIG_SPARSEMEM /* * Initialize the hole in the range [zone_end_pfn, section_end]. * If zone boundary falls in the middle of a section, this hole * will be re-initialized during the call to this function for the * higher zone. */ end_pfn = round_up(zone_end_pfn, PAGES_PER_SECTION); if (hole_pfn < end_pfn) pgcnt += init_unavailable_range(hole_pfn, end_pfn, zone_id, nid); #endif if (pgcnt) pr_info(" %s zone: %llu pages in unavailable ranges\n", zone->name, pgcnt); } static int zone_batchsize(struct zone *zone) { #ifdef CONFIG_MMU int batch; /* * The per-cpu-pages pools are set to around 1000th of the * size of the zone. */ batch = zone_managed_pages(zone) / 1024; /* But no more than a meg. */ if (batch * PAGE_SIZE > 1024 * 1024) batch = (1024 * 1024) / PAGE_SIZE; batch /= 4; /* We effectively *= 4 below */ if (batch < 1) batch = 1; /* * Clamp the batch to a 2^n - 1 value. Having a power * of 2 value was found to be more likely to have * suboptimal cache aliasing properties in some cases. * * For example if 2 tasks are alternately allocating * batches of pages, one task can end up with a lot * of pages of one half of the possible page colors * and the other with pages of the other colors. */ batch = rounddown_pow_of_two(batch + batch/2) - 1; return batch; #else /* The deferral and batching of frees should be suppressed under NOMMU * conditions. * * The problem is that NOMMU needs to be able to allocate large chunks * of contiguous memory as there's no hardware page translation to * assemble apparent contiguous memory from discontiguous pages. * * Queueing large contiguous runs of pages for batching, however, * causes the pages to actually be freed in smaller chunks. As there * can be a significant delay between the individual batches being * recycled, this leads to the once large chunks of space being * fragmented and becoming unavailable for high-order allocations. */ return 0; #endif } /* * pcp->high and pcp->batch values are related and generally batch is lower * than high. They are also related to pcp->count such that count is lower * than high, and as soon as it reaches high, the pcplist is flushed. * * However, guaranteeing these relations at all times would require e.g. write * barriers here but also careful usage of read barriers at the read side, and * thus be prone to error and bad for performance. Thus the update only prevents * store tearing. Any new users of pcp->batch and pcp->high should ensure they * can cope with those fields changing asynchronously, and fully trust only the * pcp->count field on the local CPU with interrupts disabled. * * mutex_is_locked(&pcp_batch_high_lock) required when calling this function * outside of boot time (or some other assurance that no concurrent updaters * exist). */ static void pageset_update(struct per_cpu_pages *pcp, unsigned long high, unsigned long batch) { WRITE_ONCE(pcp->batch, batch); WRITE_ONCE(pcp->high, high); } static void pageset_init(struct per_cpu_pageset *p) { struct per_cpu_pages *pcp; int migratetype; memset(p, 0, sizeof(*p)); pcp = &p->pcp; for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++) INIT_LIST_HEAD(&pcp->lists[migratetype]); /* * Set batch and high values safe for a boot pageset. A true percpu * pageset's initialization will update them subsequently. Here we don't * need to be as careful as pageset_update() as nobody can access the * pageset yet. */ pcp->high = BOOT_PAGESET_HIGH; pcp->batch = BOOT_PAGESET_BATCH; } static void __zone_set_pageset_high_and_batch(struct zone *zone, unsigned long high, unsigned long batch) { struct per_cpu_pageset *p; int cpu; for_each_possible_cpu(cpu) { p = per_cpu_ptr(zone->pageset, cpu); pageset_update(&p->pcp, high, batch); } } /* * Calculate and set new high and batch values for all per-cpu pagesets of a * zone, based on the zone's size and the percpu_pagelist_fraction sysctl. */ static void zone_set_pageset_high_and_batch(struct zone *zone) { unsigned long new_high, new_batch; if (percpu_pagelist_fraction) { new_high = zone_managed_pages(zone) / percpu_pagelist_fraction; new_batch = max(1UL, new_high / 4); if ((new_high / 4) > (PAGE_SHIFT * 8)) new_batch = PAGE_SHIFT * 8; } else { new_batch = zone_batchsize(zone); new_high = 6 * new_batch; new_batch = max(1UL, 1 * new_batch); } if (zone->pageset_high == new_high && zone->pageset_batch == new_batch) return; zone->pageset_high = new_high; zone->pageset_batch = new_batch; __zone_set_pageset_high_and_batch(zone, new_high, new_batch); } void __meminit setup_zone_pageset(struct zone *zone) { struct per_cpu_pageset *p; int cpu; zone->pageset = alloc_percpu(struct per_cpu_pageset); for_each_possible_cpu(cpu) { p = per_cpu_ptr(zone->pageset, cpu); pageset_init(p); } zone_set_pageset_high_and_batch(zone); } /* * Allocate per cpu pagesets and initialize them. * Before this call only boot pagesets were available. */ void __init setup_per_cpu_pageset(void) { struct pglist_data *pgdat; struct zone *zone; int __maybe_unused cpu; for_each_populated_zone(zone) setup_zone_pageset(zone); #ifdef CONFIG_NUMA /* * Unpopulated zones continue using the boot pagesets. * The numa stats for these pagesets need to be reset. * Otherwise, they will end up skewing the stats of * the nodes these zones are associated with. */ for_each_possible_cpu(cpu) { struct per_cpu_pageset *pcp = &per_cpu(boot_pageset, cpu); memset(pcp->vm_numa_stat_diff, 0, sizeof(pcp->vm_numa_stat_diff)); } #endif for_each_online_pgdat(pgdat) pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat); } static __meminit void zone_pcp_init(struct zone *zone) { /* * per cpu subsystem is not up at this point. The following code * relies on the ability of the linker to provide the * offset of a (static) per cpu variable into the per cpu area. */ zone->pageset = &boot_pageset; zone->pageset_high = BOOT_PAGESET_HIGH; zone->pageset_batch = BOOT_PAGESET_BATCH; if (populated_zone(zone)) printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n", zone->name, zone->present_pages, zone_batchsize(zone)); } void __meminit init_currently_empty_zone(struct zone *zone, unsigned long zone_start_pfn, unsigned long size) { struct pglist_data *pgdat = zone->zone_pgdat; int zone_idx = zone_idx(zone) + 1; if (zone_idx > pgdat->nr_zones) pgdat->nr_zones = zone_idx; zone->zone_start_pfn = zone_start_pfn; mminit_dprintk(MMINIT_TRACE, "memmap_init", "Initialising map node %d zone %lu pfns %lu -> %lu\n", pgdat->node_id, (unsigned long)zone_idx(zone), zone_start_pfn, (zone_start_pfn + size)); zone_init_free_lists(zone); zone->initialized = 1; } /** * get_pfn_range_for_nid - Return the start and end page frames for a node * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned. * @start_pfn: Passed by reference. On return, it will have the node start_pfn. * @end_pfn: Passed by reference. On return, it will have the node end_pfn. * * It returns the start and end page frame of a node based on information * provided by memblock_set_node(). If called for a node * with no available memory, a warning is printed and the start and end * PFNs will be 0. */ void __init get_pfn_range_for_nid(unsigned int nid, unsigned long *start_pfn, unsigned long *end_pfn) { unsigned long this_start_pfn, this_end_pfn; int i; *start_pfn = -1UL; *end_pfn = 0; for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) { *start_pfn = min(*start_pfn, this_start_pfn); *end_pfn = max(*end_pfn, this_end_pfn); } if (*start_pfn == -1UL) *start_pfn = 0; } /* * This finds a zone that can be used for ZONE_MOVABLE pages. The * assumption is made that zones within a node are ordered in monotonic * increasing memory addresses so that the "highest" populated zone is used */ static void __init find_usable_zone_for_movable(void) { int zone_index; for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) { if (zone_index == ZONE_MOVABLE) continue; if (arch_zone_highest_possible_pfn[zone_index] > arch_zone_lowest_possible_pfn[zone_index]) break; } VM_BUG_ON(zone_index == -1); movable_zone = zone_index; } /* * The zone ranges provided by the architecture do not include ZONE_MOVABLE * because it is sized independent of architecture. Unlike the other zones, * the starting point for ZONE_MOVABLE is not fixed. It may be different * in each node depending on the size of each node and how evenly kernelcore * is distributed. This helper function adjusts the zone ranges * provided by the architecture for a given node by using the end of the * highest usable zone for ZONE_MOVABLE. This preserves the assumption that * zones within a node are in order of monotonic increases memory addresses */ static void __init adjust_zone_range_for_zone_movable(int nid, unsigned long zone_type, unsigned long node_start_pfn, unsigned long node_end_pfn, unsigned long *zone_start_pfn, unsigned long *zone_end_pfn) { /* Only adjust if ZONE_MOVABLE is on this node */ if (zone_movable_pfn[nid]) { /* Size ZONE_MOVABLE */ if (zone_type == ZONE_MOVABLE) { *zone_start_pfn = zone_movable_pfn[nid]; *zone_end_pfn = min(node_end_pfn, arch_zone_highest_possible_pfn[movable_zone]); /* Adjust for ZONE_MOVABLE starting within this range */ } else if (!mirrored_kernelcore && *zone_start_pfn < zone_movable_pfn[nid] && *zone_end_pfn > zone_movable_pfn[nid]) { *zone_end_pfn = zone_movable_pfn[nid]; /* Check if this whole range is within ZONE_MOVABLE */ } else if (*zone_start_pfn >= zone_movable_pfn[nid]) *zone_start_pfn = *zone_end_pfn; } } /* * Return the number of pages a zone spans in a node, including holes * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node() */ static unsigned long __init zone_spanned_pages_in_node(int nid, unsigned long zone_type, unsigned long node_start_pfn, unsigned long node_end_pfn, unsigned long *zone_start_pfn, unsigned long *zone_end_pfn) { unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type]; unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type]; /* When hotadd a new node from cpu_up(), the node should be empty */ if (!node_start_pfn && !node_end_pfn) return 0; /* Get the start and end of the zone */ *zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high); *zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high); adjust_zone_range_for_zone_movable(nid, zone_type, node_start_pfn, node_end_pfn, zone_start_pfn, zone_end_pfn); /* Check that this node has pages within the zone's required range */ if (*zone_end_pfn < node_start_pfn || *zone_start_pfn > node_end_pfn) return 0; /* Move the zone boundaries inside the node if necessary */ *zone_end_pfn = min(*zone_end_pfn, node_end_pfn); *zone_start_pfn = max(*zone_start_pfn, node_start_pfn); /* Return the spanned pages */ return *zone_end_pfn - *zone_start_pfn; } /* * Return the number of holes in a range on a node. If nid is MAX_NUMNODES, * then all holes in the requested range will be accounted for. */ unsigned long __init __absent_pages_in_range(int nid, unsigned long range_start_pfn, unsigned long range_end_pfn) { unsigned long nr_absent = range_end_pfn - range_start_pfn; unsigned long start_pfn, end_pfn; int i; for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) { start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn); end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn); nr_absent -= end_pfn - start_pfn; } return nr_absent; } /** * absent_pages_in_range - Return number of page frames in holes within a range * @start_pfn: The start PFN to start searching for holes * @end_pfn: The end PFN to stop searching for holes * * Return: the number of pages frames in memory holes within a range. */ unsigned long __init absent_pages_in_range(unsigned long start_pfn, unsigned long end_pfn) { return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn); } /* Return the number of page frames in holes in a zone on a node */ static unsigned long __init zone_absent_pages_in_node(int nid, unsigned long zone_type, unsigned long node_start_pfn, unsigned long node_end_pfn) { unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type]; unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type]; unsigned long zone_start_pfn, zone_end_pfn; unsigned long nr_absent; /* When hotadd a new node from cpu_up(), the node should be empty */ if (!node_start_pfn && !node_end_pfn) return 0; zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high); zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high); adjust_zone_range_for_zone_movable(nid, zone_type, node_start_pfn, node_end_pfn, &zone_start_pfn, &zone_end_pfn); nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn); /* * ZONE_MOVABLE handling. * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages * and vice versa. */ if (mirrored_kernelcore && zone_movable_pfn[nid]) { unsigned long start_pfn, end_pfn; struct memblock_region *r; for_each_mem_region(r) { start_pfn = clamp(memblock_region_memory_base_pfn(r), zone_start_pfn, zone_end_pfn); end_pfn = clamp(memblock_region_memory_end_pfn(r), zone_start_pfn, zone_end_pfn); if (zone_type == ZONE_MOVABLE && memblock_is_mirror(r)) nr_absent += end_pfn - start_pfn; if (zone_type == ZONE_NORMAL && !memblock_is_mirror(r)) nr_absent += end_pfn - start_pfn; } } return nr_absent; } static void __init calculate_node_totalpages(struct pglist_data *pgdat, unsigned long node_start_pfn, unsigned long node_end_pfn) { unsigned long realtotalpages = 0, totalpages = 0; enum zone_type i; for (i = 0; i < MAX_NR_ZONES; i++) { struct zone *zone = pgdat->node_zones + i; unsigned long zone_start_pfn, zone_end_pfn; unsigned long spanned, absent; unsigned long size, real_size; spanned = zone_spanned_pages_in_node(pgdat->node_id, i, node_start_pfn, node_end_pfn, &zone_start_pfn, &zone_end_pfn); absent = zone_absent_pages_in_node(pgdat->node_id, i, node_start_pfn, node_end_pfn); size = spanned; real_size = size - absent; if (size) zone->zone_start_pfn = zone_start_pfn; else zone->zone_start_pfn = 0; zone->spanned_pages = size; zone->present_pages = real_size; totalpages += size; realtotalpages += real_size; } pgdat->node_spanned_pages = totalpages; pgdat->node_present_pages = realtotalpages; printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id, realtotalpages); } #ifndef CONFIG_SPARSEMEM /* * Calculate the size of the zone->blockflags rounded to an unsigned long * Start by making sure zonesize is a multiple of pageblock_order by rounding * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally * round what is now in bits to nearest long in bits, then return it in * bytes. */ static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize) { unsigned long usemapsize; zonesize += zone_start_pfn & (pageblock_nr_pages-1); usemapsize = roundup(zonesize, pageblock_nr_pages); usemapsize = usemapsize >> pageblock_order; usemapsize *= NR_PAGEBLOCK_BITS; usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long)); return usemapsize / 8; } static void __ref setup_usemap(struct zone *zone) { unsigned long usemapsize = usemap_size(zone->zone_start_pfn, zone->spanned_pages); zone->pageblock_flags = NULL; if (usemapsize) { zone->pageblock_flags = memblock_alloc_node(usemapsize, SMP_CACHE_BYTES, zone_to_nid(zone)); if (!zone->pageblock_flags) panic("Failed to allocate %ld bytes for zone %s pageblock flags on node %d\n", usemapsize, zone->name, zone_to_nid(zone)); } } #else static inline void setup_usemap(struct zone *zone) {} #endif /* CONFIG_SPARSEMEM */ #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */ void __init set_pageblock_order(void) { unsigned int order; /* Check that pageblock_nr_pages has not already been setup */ if (pageblock_order) return; if (HPAGE_SHIFT > PAGE_SHIFT) order = HUGETLB_PAGE_ORDER; else order = MAX_ORDER - 1; /* * Assume the largest contiguous order of interest is a huge page. * This value may be variable depending on boot parameters on IA64 and * powerpc. */ pageblock_order = order; } #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */ /* * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order() * is unused as pageblock_order is set at compile-time. See * include/linux/pageblock-flags.h for the values of pageblock_order based on * the kernel config */ void __init set_pageblock_order(void) { } #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */ static unsigned long __init calc_memmap_size(unsigned long spanned_pages, unsigned long present_pages) { unsigned long pages = spanned_pages; /* * Provide a more accurate estimation if there are holes within * the zone and SPARSEMEM is in use. If there are holes within the * zone, each populated memory region may cost us one or two extra * memmap pages due to alignment because memmap pages for each * populated regions may not be naturally aligned on page boundary. * So the (present_pages >> 4) heuristic is a tradeoff for that. */ if (spanned_pages > present_pages + (present_pages >> 4) && IS_ENABLED(CONFIG_SPARSEMEM)) pages = present_pages; return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT; } #ifdef CONFIG_TRANSPARENT_HUGEPAGE static void pgdat_init_split_queue(struct pglist_data *pgdat) { struct deferred_split *ds_queue = &pgdat->deferred_split_queue; spin_lock_init(&ds_queue->split_queue_lock); INIT_LIST_HEAD(&ds_queue->split_queue); ds_queue->split_queue_len = 0; } #else static void pgdat_init_split_queue(struct pglist_data *pgdat) {} #endif #ifdef CONFIG_COMPACTION static void pgdat_init_kcompactd(struct pglist_data *pgdat) { init_waitqueue_head(&pgdat->kcompactd_wait); } #else static void pgdat_init_kcompactd(struct pglist_data *pgdat) {} #endif static void __meminit pgdat_init_internals(struct pglist_data *pgdat) { pgdat_resize_init(pgdat); pgdat_init_split_queue(pgdat); pgdat_init_kcompactd(pgdat); init_waitqueue_head(&pgdat->kswapd_wait); init_waitqueue_head(&pgdat->pfmemalloc_wait); pgdat_page_ext_init(pgdat); lruvec_init(&pgdat->__lruvec); } static void __meminit zone_init_internals(struct zone *zone, enum zone_type idx, int nid, unsigned long remaining_pages) { atomic_long_set(&zone->managed_pages, remaining_pages); zone_set_nid(zone, nid); zone->name = zone_names[idx]; zone->zone_pgdat = NODE_DATA(nid); spin_lock_init(&zone->lock); zone_seqlock_init(zone); zone_pcp_init(zone); } /* * Set up the zone data structures * - init pgdat internals * - init all zones belonging to this node * * NOTE: this function is only called during memory hotplug */ #ifdef CONFIG_MEMORY_HOTPLUG void __ref free_area_init_core_hotplug(int nid) { enum zone_type z; pg_data_t *pgdat = NODE_DATA(nid); pgdat_init_internals(pgdat); for (z = 0; z < MAX_NR_ZONES; z++) zone_init_internals(&pgdat->node_zones[z], z, nid, 0); } #endif /* * Set up the zone data structures: * - mark all pages reserved * - mark all memory queues empty * - clear the memory bitmaps * * NOTE: pgdat should get zeroed by caller. * NOTE: this function is only called during early init. */ static void __init free_area_init_core(struct pglist_data *pgdat) { enum zone_type j; int nid = pgdat->node_id; pgdat_init_internals(pgdat); pgdat->per_cpu_nodestats = &boot_nodestats; for (j = 0; j < MAX_NR_ZONES; j++) { struct zone *zone = pgdat->node_zones + j; unsigned long size, freesize, memmap_pages; size = zone->spanned_pages; freesize = zone->present_pages; /* * Adjust freesize so that it accounts for how much memory * is used by this zone for memmap. This affects the watermark * and per-cpu initialisations */ memmap_pages = calc_memmap_size(size, freesize); if (!is_highmem_idx(j)) { if (freesize >= memmap_pages) { freesize -= memmap_pages; if (memmap_pages) printk(KERN_DEBUG " %s zone: %lu pages used for memmap\n", zone_names[j], memmap_pages); } else pr_warn(" %s zone: %lu pages exceeds freesize %lu\n", zone_names[j], memmap_pages, freesize); } /* Account for reserved pages */ if (j == 0 && freesize > dma_reserve) { freesize -= dma_reserve; printk(KERN_DEBUG " %s zone: %lu pages reserved\n", zone_names[0], dma_reserve); } if (!is_highmem_idx(j)) nr_kernel_pages += freesize; /* Charge for highmem memmap if there are enough kernel pages */ else if (nr_kernel_pages > memmap_pages * 2) nr_kernel_pages -= memmap_pages; nr_all_pages += freesize; /* * Set an approximate value for lowmem here, it will be adjusted * when the bootmem allocator frees pages into the buddy system. * And all highmem pages will be managed by the buddy system. */ zone_init_internals(zone, j, nid, freesize); if (!size) continue; set_pageblock_order(); setup_usemap(zone); init_currently_empty_zone(zone, zone->zone_start_pfn, size); memmap_init_zone(zone); } } #ifdef CONFIG_FLAT_NODE_MEM_MAP static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { unsigned long __maybe_unused start = 0; unsigned long __maybe_unused offset = 0; /* Skip empty nodes */ if (!pgdat->node_spanned_pages) return; start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1); offset = pgdat->node_start_pfn - start; /* ia64 gets its own node_mem_map, before this, without bootmem */ if (!pgdat->node_mem_map) { unsigned long size, end; struct page *map; /* * The zone's endpoints aren't required to be MAX_ORDER * aligned but the node_mem_map endpoints must be in order * for the buddy allocator to function correctly. */ end = pgdat_end_pfn(pgdat); end = ALIGN(end, MAX_ORDER_NR_PAGES); size = (end - start) * sizeof(struct page); map = memblock_alloc_node(size, SMP_CACHE_BYTES, pgdat->node_id); if (!map) panic("Failed to allocate %ld bytes for node %d memory map\n", size, pgdat->node_id); pgdat->node_mem_map = map + offset; } pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n", __func__, pgdat->node_id, (unsigned long)pgdat, (unsigned long)pgdat->node_mem_map); #ifndef CONFIG_NEED_MULTIPLE_NODES /* * With no DISCONTIG, the global mem_map is just set as node 0's */ if (pgdat == NODE_DATA(0)) { mem_map = NODE_DATA(0)->node_mem_map; if (page_to_pfn(mem_map) != pgdat->node_start_pfn) mem_map -= offset; } #endif } #else static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { } #endif /* CONFIG_FLAT_NODE_MEM_MAP */ #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT static inline void pgdat_set_deferred_range(pg_data_t *pgdat) { pgdat->first_deferred_pfn = ULONG_MAX; } #else static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {} #endif static void __init free_area_init_node(int nid) { pg_data_t *pgdat = NODE_DATA(nid); unsigned long start_pfn = 0; unsigned long end_pfn = 0; /* pg_data_t should be reset to zero when it's allocated */ WARN_ON(pgdat->nr_zones || pgdat->kswapd_highest_zoneidx); get_pfn_range_for_nid(nid, &start_pfn, &end_pfn); pgdat->node_id = nid; pgdat->node_start_pfn = start_pfn; pgdat->per_cpu_nodestats = NULL; pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid, (u64)start_pfn << PAGE_SHIFT, end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0); calculate_node_totalpages(pgdat, start_pfn, end_pfn); alloc_node_mem_map(pgdat); pgdat_set_deferred_range(pgdat); free_area_init_core(pgdat); } void __init free_area_init_memoryless_node(int nid) { free_area_init_node(nid); } #if MAX_NUMNODES > 1 /* * Figure out the number of possible node ids. */ void __init setup_nr_node_ids(void) { unsigned int highest; highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES); nr_node_ids = highest + 1; } #endif /** * node_map_pfn_alignment - determine the maximum internode alignment * * This function should be called after node map is populated and sorted. * It calculates the maximum power of two alignment which can distinguish * all the nodes. * * For example, if all nodes are 1GiB and aligned to 1GiB, the return value * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)). If the * nodes are shifted by 256MiB, 256MiB. Note that if only the last node is * shifted, 1GiB is enough and this function will indicate so. * * This is used to test whether pfn -> nid mapping of the chosen memory * model has fine enough granularity to avoid incorrect mapping for the * populated node map. * * Return: the determined alignment in pfn's. 0 if there is no alignment * requirement (single node). */ unsigned long __init node_map_pfn_alignment(void) { unsigned long accl_mask = 0, last_end = 0; unsigned long start, end, mask; int last_nid = NUMA_NO_NODE; int i, nid; for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) { if (!start || last_nid < 0 || last_nid == nid) { last_nid = nid; last_end = end; continue; } /* * Start with a mask granular enough to pin-point to the * start pfn and tick off bits one-by-one until it becomes * too coarse to separate the current node from the last. */ mask = ~((1 << __ffs(start)) - 1); while (mask && last_end <= (start & (mask << 1))) mask <<= 1; /* accumulate all internode masks */ accl_mask |= mask; } /* convert mask to number of pages */ return ~accl_mask + 1; } /** * find_min_pfn_with_active_regions - Find the minimum PFN registered * * Return: the minimum PFN based on information provided via * memblock_set_node(). */ unsigned long __init find_min_pfn_with_active_regions(void) { return PHYS_PFN(memblock_start_of_DRAM()); } /* * early_calculate_totalpages() * Sum pages in active regions for movable zone. * Populate N_MEMORY for calculating usable_nodes. */ static unsigned long __init early_calculate_totalpages(void) { unsigned long totalpages = 0; unsigned long start_pfn, end_pfn; int i, nid; for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { unsigned long pages = end_pfn - start_pfn; totalpages += pages; if (pages) node_set_state(nid, N_MEMORY); } return totalpages; } /* * Find the PFN the Movable zone begins in each node. Kernel memory * is spread evenly between nodes as long as the nodes have enough * memory. When they don't, some nodes will have more kernelcore than * others */ static void __init find_zone_movable_pfns_for_nodes(void) { int i, nid; unsigned long usable_startpfn; unsigned long kernelcore_node, kernelcore_remaining; /* save the state before borrow the nodemask */ nodemask_t saved_node_state = node_states[N_MEMORY]; unsigned long totalpages = early_calculate_totalpages(); int usable_nodes = nodes_weight(node_states[N_MEMORY]); struct memblock_region *r; /* Need to find movable_zone earlier when movable_node is specified. */ find_usable_zone_for_movable(); /* * If movable_node is specified, ignore kernelcore and movablecore * options. */ if (movable_node_is_enabled()) { for_each_mem_region(r) { if (!memblock_is_hotpluggable(r)) continue; nid = memblock_get_region_node(r); usable_startpfn = PFN_DOWN(r->base); zone_movable_pfn[nid] = zone_movable_pfn[nid] ? min(usable_startpfn, zone_movable_pfn[nid]) : usable_startpfn; } goto out2; } /* * If kernelcore=mirror is specified, ignore movablecore option */ if (mirrored_kernelcore) { bool mem_below_4gb_not_mirrored = false; for_each_mem_region(r) { if (memblock_is_mirror(r)) continue; nid = memblock_get_region_node(r); usable_startpfn = memblock_region_memory_base_pfn(r); if (usable_startpfn < 0x100000) { mem_below_4gb_not_mirrored = true; continue; } zone_movable_pfn[nid] = zone_movable_pfn[nid] ? min(usable_startpfn, zone_movable_pfn[nid]) : usable_startpfn; } if (mem_below_4gb_not_mirrored) pr_warn("This configuration results in unmirrored kernel memory.\n"); goto out2; } /* * If kernelcore=nn% or movablecore=nn% was specified, calculate the * amount of necessary memory. */ if (required_kernelcore_percent) required_kernelcore = (totalpages * 100 * required_kernelcore_percent) / 10000UL; if (required_movablecore_percent) required_movablecore = (totalpages * 100 * required_movablecore_percent) / 10000UL; /* * If movablecore= was specified, calculate what size of * kernelcore that corresponds so that memory usable for * any allocation type is evenly spread. If both kernelcore * and movablecore are specified, then the value of kernelcore * will be used for required_kernelcore if it's greater than * what movablecore would have allowed. */ if (required_movablecore) { unsigned long corepages; /* * Round-up so that ZONE_MOVABLE is at least as large as what * was requested by the user */ required_movablecore = roundup(required_movablecore, MAX_ORDER_NR_PAGES); required_movablecore = min(totalpages, required_movablecore); corepages = totalpages - required_movablecore; required_kernelcore = max(required_kernelcore, corepages); } /* * If kernelcore was not specified or kernelcore size is larger * than totalpages, there is no ZONE_MOVABLE. */ if (!required_kernelcore || required_kernelcore >= totalpages) goto out; /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */ usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone]; restart: /* Spread kernelcore memory as evenly as possible throughout nodes */ kernelcore_node = required_kernelcore / usable_nodes; for_each_node_state(nid, N_MEMORY) { unsigned long start_pfn, end_pfn; /* * Recalculate kernelcore_node if the division per node * now exceeds what is necessary to satisfy the requested * amount of memory for the kernel */ if (required_kernelcore < kernelcore_node) kernelcore_node = required_kernelcore / usable_nodes; /* * As the map is walked, we track how much memory is usable * by the kernel using kernelcore_remaining. When it is * 0, the rest of the node is usable by ZONE_MOVABLE */ kernelcore_remaining = kernelcore_node; /* Go through each range of PFNs within this node */ for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) { unsigned long size_pages; start_pfn = max(start_pfn, zone_movable_pfn[nid]); if (start_pfn >= end_pfn) continue; /* Account for what is only usable for kernelcore */ if (start_pfn < usable_startpfn) { unsigned long kernel_pages; kernel_pages = min(end_pfn, usable_startpfn) - start_pfn; kernelcore_remaining -= min(kernel_pages, kernelcore_remaining); required_kernelcore -= min(kernel_pages, required_kernelcore); /* Continue if range is now fully accounted */ if (end_pfn <= usable_startpfn) { /* * Push zone_movable_pfn to the end so * that if we have to rebalance * kernelcore across nodes, we will * not double account here */ zone_movable_pfn[nid] = end_pfn; continue; } start_pfn = usable_startpfn; } /* * The usable PFN range for ZONE_MOVABLE is from * start_pfn->end_pfn. Calculate size_pages as the * number of pages used as kernelcore */ size_pages = end_pfn - start_pfn; if (size_pages > kernelcore_remaining) size_pages = kernelcore_remaining; zone_movable_pfn[nid] = start_pfn + size_pages; /* * Some kernelcore has been met, update counts and * break if the kernelcore for this node has been * satisfied */ required_kernelcore -= min(required_kernelcore, size_pages); kernelcore_remaining -= size_pages; if (!kernelcore_remaining) break; } } /* * If there is still required_kernelcore, we do another pass with one * less node in the count. This will push zone_movable_pfn[nid] further * along on the nodes that still have memory until kernelcore is * satisfied */ usable_nodes--; if (usable_nodes && required_kernelcore > usable_nodes) goto restart; out2: /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */ for (nid = 0; nid < MAX_NUMNODES; nid++) zone_movable_pfn[nid] = roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES); out: /* restore the node_state */ node_states[N_MEMORY] = saved_node_state; } /* Any regular or high memory on that node ? */ static void check_for_memory(pg_data_t *pgdat, int nid) { enum zone_type zone_type; for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) { struct zone *zone = &pgdat->node_zones[zone_type]; if (populated_zone(zone)) { if (IS_ENABLED(CONFIG_HIGHMEM)) node_set_state(nid, N_HIGH_MEMORY); if (zone_type <= ZONE_NORMAL) node_set_state(nid, N_NORMAL_MEMORY); break; } } } /* * Some architectures, e.g. ARC may have ZONE_HIGHMEM below ZONE_NORMAL. For * such cases we allow max_zone_pfn sorted in the descending order */ bool __weak arch_has_descending_max_zone_pfns(void) { return false; } /** * free_area_init - Initialise all pg_data_t and zone data * @max_zone_pfn: an array of max PFNs for each zone * * This will call free_area_init_node() for each active node in the system. * Using the page ranges provided by memblock_set_node(), the size of each * zone in each node and their holes is calculated. If the maximum PFN * between two adjacent zones match, it is assumed that the zone is empty. * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed * that arch_max_dma32_pfn has no pages. It is also assumed that a zone * starts where the previous one ended. For example, ZONE_DMA32 starts * at arch_max_dma_pfn. */ void __init free_area_init(unsigned long *max_zone_pfn) { unsigned long start_pfn, end_pfn; int i, nid, zone; bool descending; /* Record where the zone boundaries are */ memset(arch_zone_lowest_possible_pfn, 0, sizeof(arch_zone_lowest_possible_pfn)); memset(arch_zone_highest_possible_pfn, 0, sizeof(arch_zone_highest_possible_pfn)); start_pfn = find_min_pfn_with_active_regions(); descending = arch_has_descending_max_zone_pfns(); for (i = 0; i < MAX_NR_ZONES; i++) { if (descending) zone = MAX_NR_ZONES - i - 1; else zone = i; if (zone == ZONE_MOVABLE) continue; end_pfn = max(max_zone_pfn[zone], start_pfn); arch_zone_lowest_possible_pfn[zone] = start_pfn; arch_zone_highest_possible_pfn[zone] = end_pfn; start_pfn = end_pfn; } /* Find the PFNs that ZONE_MOVABLE begins at in each node */ memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn)); find_zone_movable_pfns_for_nodes(); /* Print out the zone ranges */ pr_info("Zone ranges:\n"); for (i = 0; i < MAX_NR_ZONES; i++) { if (i == ZONE_MOVABLE) continue; pr_info(" %-8s ", zone_names[i]); if (arch_zone_lowest_possible_pfn[i] == arch_zone_highest_possible_pfn[i]) pr_cont("empty\n"); else pr_cont("[mem %#018Lx-%#018Lx]\n", (u64)arch_zone_lowest_possible_pfn[i] << PAGE_SHIFT, ((u64)arch_zone_highest_possible_pfn[i] << PAGE_SHIFT) - 1); } /* Print out the PFNs ZONE_MOVABLE begins at in each node */ pr_info("Movable zone start for each node\n"); for (i = 0; i < MAX_NUMNODES; i++) { if (zone_movable_pfn[i]) pr_info(" Node %d: %#018Lx\n", i, (u64)zone_movable_pfn[i] << PAGE_SHIFT); } /* * Print out the early node map, and initialize the * subsection-map relative to active online memory ranges to * enable future "sub-section" extensions of the memory map. */ pr_info("Early memory node ranges\n"); for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid, (u64)start_pfn << PAGE_SHIFT, ((u64)end_pfn << PAGE_SHIFT) - 1); subsection_map_init(start_pfn, end_pfn - start_pfn); } /* Initialise every node */ mminit_verify_pageflags_layout(); setup_nr_node_ids(); for_each_online_node(nid) { pg_data_t *pgdat = NODE_DATA(nid); free_area_init_node(nid); /* Any memory on that node */ if (pgdat->node_present_pages) node_set_state(nid, N_MEMORY); check_for_memory(pgdat, nid); } } static int __init cmdline_parse_core(char *p, unsigned long *core, unsigned long *percent) { unsigned long long coremem; char *endptr; if (!p) return -EINVAL; /* Value may be a percentage of total memory, otherwise bytes */ coremem = simple_strtoull(p, &endptr, 0); if (*endptr == '%') { /* Paranoid check for percent values greater than 100 */ WARN_ON(coremem > 100); *percent = coremem; } else { coremem = memparse(p, &p); /* Paranoid check that UL is enough for the coremem value */ WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX); *core = coremem >> PAGE_SHIFT; *percent = 0UL; } return 0; } /* * kernelcore=size sets the amount of memory for use for allocations that * cannot be reclaimed or migrated. */ static int __init cmdline_parse_kernelcore(char *p) { /* parse kernelcore=mirror */ if (parse_option_str(p, "mirror")) { mirrored_kernelcore = true; return 0; } return cmdline_parse_core(p, &required_kernelcore, &required_kernelcore_percent); } /* * movablecore=size sets the amount of memory for use for allocations that * can be reclaimed or migrated. */ static int __init cmdline_parse_movablecore(char *p) { return cmdline_parse_core(p, &required_movablecore, &required_movablecore_percent); } early_param("kernelcore", cmdline_parse_kernelcore); early_param("movablecore", cmdline_parse_movablecore); void adjust_managed_page_count(struct page *page, long count) { atomic_long_add(count, &page_zone(page)->managed_pages); totalram_pages_add(count); #ifdef CONFIG_HIGHMEM if (PageHighMem(page)) totalhigh_pages_add(count); #endif } EXPORT_SYMBOL(adjust_managed_page_count); unsigned long free_reserved_area(void *start, void *end, int poison, const char *s) { void *pos; unsigned long pages = 0; start = (void *)PAGE_ALIGN((unsigned long)start); end = (void *)((unsigned long)end & PAGE_MASK); for (pos = start; pos < end; pos += PAGE_SIZE, pages++) { struct page *page = virt_to_page(pos); void *direct_map_addr; /* * 'direct_map_addr' might be different from 'pos' * because some architectures' virt_to_page() * work with aliases. Getting the direct map * address ensures that we get a _writeable_ * alias for the memset(). */ direct_map_addr = page_address(page); /* * Perform a kasan-unchecked memset() since this memory * has not been initialized. */ direct_map_addr = kasan_reset_tag(direct_map_addr); if ((unsigned int)poison <= 0xFF) memset(direct_map_addr, poison, PAGE_SIZE); free_reserved_page(page); } if (pages && s) pr_info("Freeing %s memory: %ldK\n", s, pages << (PAGE_SHIFT - 10)); return pages; } void __init mem_init_print_info(void) { unsigned long physpages, codesize, datasize, rosize, bss_size; unsigned long init_code_size, init_data_size; physpages = get_num_physpages(); codesize = _etext - _stext; datasize = _edata - _sdata; rosize = __end_rodata - __start_rodata; bss_size = __bss_stop - __bss_start; init_data_size = __init_end - __init_begin; init_code_size = _einittext - _sinittext; /* * Detect special cases and adjust section sizes accordingly: * 1) .init.* may be embedded into .data sections * 2) .init.text.* may be out of [__init_begin, __init_end], * please refer to arch/tile/kernel/vmlinux.lds.S. * 3) .rodata.* may be embedded into .text or .data sections. */ #define adj_init_size(start, end, size, pos, adj) \ do { \ if (start <= pos && pos < end && size > adj) \ size -= adj; \ } while (0) adj_init_size(__init_begin, __init_end, init_data_size, _sinittext, init_code_size); adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size); adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size); adj_init_size(_stext, _etext, codesize, __start_rodata, rosize); adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize); #undef adj_init_size pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved" #ifdef CONFIG_HIGHMEM ", %luK highmem" #endif ")\n", nr_free_pages() << (PAGE_SHIFT - 10), physpages << (PAGE_SHIFT - 10), codesize >> 10, datasize >> 10, rosize >> 10, (init_data_size + init_code_size) >> 10, bss_size >> 10, (physpages - totalram_pages() - totalcma_pages) << (PAGE_SHIFT - 10), totalcma_pages << (PAGE_SHIFT - 10) #ifdef CONFIG_HIGHMEM , totalhigh_pages() << (PAGE_SHIFT - 10) #endif ); } /** * set_dma_reserve - set the specified number of pages reserved in the first zone * @new_dma_reserve: The number of pages to mark reserved * * The per-cpu batchsize and zone watermarks are determined by managed_pages. * In the DMA zone, a significant percentage may be consumed by kernel image * and other unfreeable allocations which can skew the watermarks badly. This * function may optionally be used to account for unfreeable pages in the * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and * smaller per-cpu batchsize. */ void __init set_dma_reserve(unsigned long new_dma_reserve) { dma_reserve = new_dma_reserve; } static int page_alloc_cpu_dead(unsigned int cpu) { lru_add_drain_cpu(cpu); drain_pages(cpu); /* * Spill the event counters of the dead processor * into the current processors event counters. * This artificially elevates the count of the current * processor. */ vm_events_fold_cpu(cpu); /* * Zero the differential counters of the dead processor * so that the vm statistics are consistent. * * This is only okay since the processor is dead and cannot * race with what we are doing. */ cpu_vm_stats_fold(cpu); return 0; } #ifdef CONFIG_NUMA int hashdist = HASHDIST_DEFAULT; static int __init set_hashdist(char *str) { if (!str) return 0; hashdist = simple_strtoul(str, &str, 0); return 1; } __setup("hashdist=", set_hashdist); #endif void __init page_alloc_init(void) { int ret; #ifdef CONFIG_NUMA if (num_node_state(N_MEMORY) == 1) hashdist = 0; #endif ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC_DEAD, "mm/page_alloc:dead", NULL, page_alloc_cpu_dead); WARN_ON(ret < 0); } /* * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio * or min_free_kbytes changes. */ static void calculate_totalreserve_pages(void) { struct pglist_data *pgdat; unsigned long reserve_pages = 0; enum zone_type i, j; for_each_online_pgdat(pgdat) { pgdat->totalreserve_pages = 0; for (i = 0; i < MAX_NR_ZONES; i++) { struct zone *zone = pgdat->node_zones + i; long max = 0; unsigned long managed_pages = zone_managed_pages(zone); /* Find valid and maximum lowmem_reserve in the zone */ for (j = i; j < MAX_NR_ZONES; j++) { if (zone->lowmem_reserve[j] > max) max = zone->lowmem_reserve[j]; } /* we treat the high watermark as reserved pages. */ max += high_wmark_pages(zone); if (max > managed_pages) max = managed_pages; pgdat->totalreserve_pages += max; reserve_pages += max; } } totalreserve_pages = reserve_pages; } /* * setup_per_zone_lowmem_reserve - called whenever * sysctl_lowmem_reserve_ratio changes. Ensures that each zone * has a correct pages reserved value, so an adequate number of * pages are left in the zone after a successful __alloc_pages(). */ static void setup_per_zone_lowmem_reserve(void) { struct pglist_data *pgdat; enum zone_type i, j; for_each_online_pgdat(pgdat) { for (i = 0; i < MAX_NR_ZONES - 1; i++) { struct zone *zone = &pgdat->node_zones[i]; int ratio = sysctl_lowmem_reserve_ratio[i]; bool clear = !ratio || !zone_managed_pages(zone); unsigned long managed_pages = 0; for (j = i + 1; j < MAX_NR_ZONES; j++) { if (clear) { zone->lowmem_reserve[j] = 0; } else { struct zone *upper_zone = &pgdat->node_zones[j]; managed_pages += zone_managed_pages(upper_zone); zone->lowmem_reserve[j] = managed_pages / ratio; } } } } /* update totalreserve_pages */ calculate_totalreserve_pages(); } static void __setup_per_zone_wmarks(void) { unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10); unsigned long lowmem_pages = 0; struct zone *zone; unsigned long flags; /* Calculate total number of !ZONE_HIGHMEM pages */ for_each_zone(zone) { if (!is_highmem(zone)) lowmem_pages += zone_managed_pages(zone); } for_each_zone(zone) { u64 tmp; spin_lock_irqsave(&zone->lock, flags); tmp = (u64)pages_min * zone_managed_pages(zone); do_div(tmp, lowmem_pages); if (is_highmem(zone)) { /* * __GFP_HIGH and PF_MEMALLOC allocations usually don't * need highmem pages, so cap pages_min to a small * value here. * * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN) * deltas control async page reclaim, and so should * not be capped for highmem. */ unsigned long min_pages; min_pages = zone_managed_pages(zone) / 1024; min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL); zone->_watermark[WMARK_MIN] = min_pages; } else { /* * If it's a lowmem zone, reserve a number of pages * proportionate to the zone's size. */ zone->_watermark[WMARK_MIN] = tmp; } /* * Set the kswapd watermarks distance according to the * scale factor in proportion to available memory, but * ensure a minimum size on small systems. */ tmp = max_t(u64, tmp >> 2, mult_frac(zone_managed_pages(zone), watermark_scale_factor, 10000)); zone->watermark_boost = 0; zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp; zone->_watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2; spin_unlock_irqrestore(&zone->lock, flags); } /* update totalreserve_pages */ calculate_totalreserve_pages(); } /** * setup_per_zone_wmarks - called when min_free_kbytes changes * or when memory is hot-{added|removed} * * Ensures that the watermark[min,low,high] values for each zone are set * correctly with respect to min_free_kbytes. */ void setup_per_zone_wmarks(void) { static DEFINE_SPINLOCK(lock); spin_lock(&lock); __setup_per_zone_wmarks(); spin_unlock(&lock); } /* * Initialise min_free_kbytes. * * For small machines we want it small (128k min). For large machines * we want it large (256MB max). But it is not linear, because network * bandwidth does not increase linearly with machine size. We use * * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy: * min_free_kbytes = sqrt(lowmem_kbytes * 16) * * which yields * * 16MB: 512k * 32MB: 724k * 64MB: 1024k * 128MB: 1448k * 256MB: 2048k * 512MB: 2896k * 1024MB: 4096k * 2048MB: 5792k * 4096MB: 8192k * 8192MB: 11584k * 16384MB: 16384k */ int __meminit init_per_zone_wmark_min(void) { unsigned long lowmem_kbytes; int new_min_free_kbytes; lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10); new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16); if (new_min_free_kbytes > user_min_free_kbytes) { min_free_kbytes = new_min_free_kbytes; if (min_free_kbytes < 128) min_free_kbytes = 128; if (min_free_kbytes > 262144) min_free_kbytes = 262144; } else { pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n", new_min_free_kbytes, user_min_free_kbytes); } setup_per_zone_wmarks(); refresh_zone_stat_thresholds(); setup_per_zone_lowmem_reserve(); #ifdef CONFIG_NUMA setup_min_unmapped_ratio(); setup_min_slab_ratio(); #endif khugepaged_min_free_kbytes_update(); return 0; } postcore_initcall(init_per_zone_wmark_min) /* * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so * that we can call two helper functions whenever min_free_kbytes * changes. */ int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { int rc; rc = proc_dointvec_minmax(table, write, buffer, length, ppos); if (rc) return rc; if (write) { user_min_free_kbytes = min_free_kbytes; setup_per_zone_wmarks(); } return 0; } int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { int rc; rc = proc_dointvec_minmax(table, write, buffer, length, ppos); if (rc) return rc; if (write) setup_per_zone_wmarks(); return 0; } #ifdef CONFIG_NUMA static void setup_min_unmapped_ratio(void) { pg_data_t *pgdat; struct zone *zone; for_each_online_pgdat(pgdat) pgdat->min_unmapped_pages = 0; for_each_zone(zone) zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) * sysctl_min_unmapped_ratio) / 100; } int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { int rc; rc = proc_dointvec_minmax(table, write, buffer, length, ppos); if (rc) return rc; setup_min_unmapped_ratio(); return 0; } static void setup_min_slab_ratio(void) { pg_data_t *pgdat; struct zone *zone; for_each_online_pgdat(pgdat) pgdat->min_slab_pages = 0; for_each_zone(zone) zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) * sysctl_min_slab_ratio) / 100; } int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { int rc; rc = proc_dointvec_minmax(table, write, buffer, length, ppos); if (rc) return rc; setup_min_slab_ratio(); return 0; } #endif /* * lowmem_reserve_ratio_sysctl_handler - just a wrapper around * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve() * whenever sysctl_lowmem_reserve_ratio changes. * * The reserve ratio obviously has absolutely no relation with the * minimum watermarks. The lowmem reserve ratio can only make sense * if in function of the boot time zone sizes. */ int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { int i; proc_dointvec_minmax(table, write, buffer, length, ppos); for (i = 0; i < MAX_NR_ZONES; i++) { if (sysctl_lowmem_reserve_ratio[i] < 1) sysctl_lowmem_reserve_ratio[i] = 0; } setup_per_zone_lowmem_reserve(); return 0; } /* * percpu_pagelist_fraction - changes the pcp->high for each zone on each * cpu. It is the fraction of total pages in each zone that a hot per cpu * pagelist can have before it gets flushed back to buddy allocator. */ int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write, void *buffer, size_t *length, loff_t *ppos) { struct zone *zone; int old_percpu_pagelist_fraction; int ret; mutex_lock(&pcp_batch_high_lock); old_percpu_pagelist_fraction = percpu_pagelist_fraction; ret = proc_dointvec_minmax(table, write, buffer, length, ppos); if (!write || ret < 0) goto out; /* Sanity checking to avoid pcp imbalance */ if (percpu_pagelist_fraction && percpu_pagelist_fraction < MIN_PERCPU_PAGELIST_FRACTION) { percpu_pagelist_fraction = old_percpu_pagelist_fraction; ret = -EINVAL; goto out; } /* No change? */ if (percpu_pagelist_fraction == old_percpu_pagelist_fraction) goto out; for_each_populated_zone(zone) zone_set_pageset_high_and_batch(zone); out: mutex_unlock(&pcp_batch_high_lock); return ret; } #ifndef __HAVE_ARCH_RESERVED_KERNEL_PAGES /* * Returns the number of pages that arch has reserved but * is not known to alloc_large_system_hash(). */ static unsigned long __init arch_reserved_kernel_pages(void) { return 0; } #endif /* * Adaptive scale is meant to reduce sizes of hash tables on large memory * machines. As memory size is increased the scale is also increased but at * slower pace. Starting from ADAPT_SCALE_BASE (64G), every time memory * quadruples the scale is increased by one, which means the size of hash table * only doubles, instead of quadrupling as well. * Because 32-bit systems cannot have large physical memory, where this scaling * makes sense, it is disabled on such platforms. */ #if __BITS_PER_LONG > 32 #define ADAPT_SCALE_BASE (64ul << 30) #define ADAPT_SCALE_SHIFT 2 #define ADAPT_SCALE_NPAGES (ADAPT_SCALE_BASE >> PAGE_SHIFT) #endif /* * allocate a large system hash table from bootmem * - it is assumed that the hash table must contain an exact power-of-2 * quantity of entries * - limit is the number of hash buckets, not the total allocation size */ void *__init alloc_large_system_hash(const char *tablename, unsigned long bucketsize, unsigned long numentries, int scale, int flags, unsigned int *_hash_shift, unsigned int *_hash_mask, unsigned long low_limit, unsigned long high_limit) { unsigned long long max = high_limit; unsigned long log2qty, size; void *table = NULL; gfp_t gfp_flags; bool virt; bool huge; /* allow the kernel cmdline to have a say */ if (!numentries) { /* round applicable memory size up to nearest megabyte */ numentries = nr_kernel_pages; numentries -= arch_reserved_kernel_pages(); /* It isn't necessary when PAGE_SIZE >= 1MB */ if (PAGE_SHIFT < 20) numentries = round_up(numentries, (1<<20)/PAGE_SIZE); #if __BITS_PER_LONG > 32 if (!high_limit) { unsigned long adapt; for (adapt = ADAPT_SCALE_NPAGES; adapt < numentries; adapt <<= ADAPT_SCALE_SHIFT) scale++; } #endif /* limit to 1 bucket per 2^scale bytes of low memory */ if (scale > PAGE_SHIFT) numentries >>= (scale - PAGE_SHIFT); else numentries <<= (PAGE_SHIFT - scale); /* Make sure we've got at least a 0-order allocation.. */ if (unlikely(flags & HASH_SMALL)) { /* Makes no sense without HASH_EARLY */ WARN_ON(!(flags & HASH_EARLY)); if (!(numentries >> *_hash_shift)) { numentries = 1UL << *_hash_shift; BUG_ON(!numentries); } } else if (unlikely((numentries * bucketsize) < PAGE_SIZE)) numentries = PAGE_SIZE / bucketsize; } numentries = roundup_pow_of_two(numentries); /* limit allocation size to 1/16 total memory by default */ if (max == 0) { max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4; do_div(max, bucketsize); } max = min(max, 0x80000000ULL); if (numentries < low_limit) numentries = low_limit; if (numentries > max) numentries = max; log2qty = ilog2(numentries); gfp_flags = (flags & HASH_ZERO) ? GFP_ATOMIC | __GFP_ZERO : GFP_ATOMIC; do { virt = false; size = bucketsize << log2qty; if (flags & HASH_EARLY) { if (flags & HASH_ZERO) table = memblock_alloc(size, SMP_CACHE_BYTES); else table = memblock_alloc_raw(size, SMP_CACHE_BYTES); } else if (get_order(size) >= MAX_ORDER || hashdist) { table = __vmalloc(size, gfp_flags); virt = true; huge = is_vm_area_hugepages(table); } else { /* * If bucketsize is not a power-of-two, we may free * some pages at the end of hash table which * alloc_pages_exact() automatically does */ table = alloc_pages_exact(size, gfp_flags); kmemleak_alloc(table, size, 1, gfp_flags); } } while (!table && size > PAGE_SIZE && --log2qty); if (!table) panic("Failed to allocate %s hash table\n", tablename); pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n", tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size, virt ? (huge ? "vmalloc hugepage" : "vmalloc") : "linear"); if (_hash_shift) *_hash_shift = log2qty; if (_hash_mask) *_hash_mask = (1 << log2qty) - 1; return table; } /* * This function checks whether pageblock includes unmovable pages or not. * * PageLRU check without isolation or lru_lock could race so that * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable * check without lock_page also may miss some movable non-lru pages at * race condition. So you can't expect this function should be exact. * * Returns a page without holding a reference. If the caller wants to * dereference that page (e.g., dumping), it has to make sure that it * cannot get removed (e.g., via memory unplug) concurrently. * */ struct page *has_unmovable_pages(struct zone *zone, struct page *page, int migratetype, int flags) { unsigned long iter = 0; unsigned long pfn = page_to_pfn(page); unsigned long offset = pfn % pageblock_nr_pages; if (is_migrate_cma_page(page)) { /* * CMA allocations (alloc_contig_range) really need to mark * isolate CMA pageblocks even when they are not movable in fact * so consider them movable here. */ if (is_migrate_cma(migratetype)) return NULL; return page; } for (; iter < pageblock_nr_pages - offset; iter++) { if (!pfn_valid_within(pfn + iter)) continue; page = pfn_to_page(pfn + iter); /* * Both, bootmem allocations and memory holes are marked * PG_reserved and are unmovable. We can even have unmovable * allocations inside ZONE_MOVABLE, for example when * specifying "movablecore". */ if (PageReserved(page)) return page; /* * If the zone is movable and we have ruled out all reserved * pages then it should be reasonably safe to assume the rest * is movable. */ if (zone_idx(zone) == ZONE_MOVABLE) continue; /* * Hugepages are not in LRU lists, but they're movable. * THPs are on the LRU, but need to be counted as #small pages. * We need not scan over tail pages because we don't * handle each tail page individually in migration. */ if (PageHuge(page) || PageTransCompound(page)) { struct page *head = compound_head(page); unsigned int skip_pages; if (PageHuge(page)) { if (!hugepage_migration_supported(page_hstate(head))) return page; } else if (!PageLRU(head) && !__PageMovable(head)) { return page; } skip_pages = compound_nr(head) - (page - head); iter += skip_pages - 1; continue; } /* * We can't use page_count without pin a page * because another CPU can free compound page. * This check already skips compound tails of THP * because their page->_refcount is zero at all time. */ if (!page_ref_count(page)) { if (PageBuddy(page)) iter += (1 << buddy_order(page)) - 1; continue; } /* * The HWPoisoned page may be not in buddy system, and * page_count() is not 0. */ if ((flags & MEMORY_OFFLINE) && PageHWPoison(page)) continue; /* * We treat all PageOffline() pages as movable when offlining * to give drivers a chance to decrement their reference count * in MEM_GOING_OFFLINE in order to indicate that these pages * can be offlined as there are no direct references anymore. * For actually unmovable PageOffline() where the driver does * not support this, we will fail later when trying to actually * move these pages that still have a reference count > 0. * (false negatives in this function only) */ if ((flags & MEMORY_OFFLINE) && PageOffline(page)) continue; if (__PageMovable(page) || PageLRU(page)) continue; /* * If there are RECLAIMABLE pages, we need to check * it. But now, memory offline itself doesn't call * shrink_node_slabs() and it still to be fixed. */ return page; } return NULL; } #ifdef CONFIG_CONTIG_ALLOC static unsigned long pfn_max_align_down(unsigned long pfn) { return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES, pageblock_nr_pages) - 1); } static unsigned long pfn_max_align_up(unsigned long pfn) { return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES, pageblock_nr_pages)); } #if defined(CONFIG_DYNAMIC_DEBUG) || \ (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) /* Usage: See admin-guide/dynamic-debug-howto.rst */ static void alloc_contig_dump_pages(struct list_head *page_list) { DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, "migrate failure"); if (DYNAMIC_DEBUG_BRANCH(descriptor)) { struct page *page; dump_stack(); list_for_each_entry(page, page_list, lru) dump_page(page, "migration failure"); } } #else static inline void alloc_contig_dump_pages(struct list_head *page_list) { } #endif /* [start, end) must belong to a single zone. */ static int __alloc_contig_migrate_range(struct compact_control *cc, unsigned long start, unsigned long end) { /* This function is based on compact_zone() from compaction.c. */ unsigned int nr_reclaimed; unsigned long pfn = start; unsigned int tries = 0; int ret = 0; struct migration_target_control mtc = { .nid = zone_to_nid(cc->zone), .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, }; lru_cache_disable(); while (pfn < end || !list_empty(&cc->migratepages)) { if (fatal_signal_pending(current)) { ret = -EINTR; break; } if (list_empty(&cc->migratepages)) { cc->nr_migratepages = 0; ret = isolate_migratepages_range(cc, pfn, end); if (ret && ret != -EAGAIN) break; pfn = cc->migrate_pfn; tries = 0; } else if (++tries == 5) { ret = -EBUSY; break; } nr_reclaimed = reclaim_clean_pages_from_list(cc->zone, &cc->migratepages); cc->nr_migratepages -= nr_reclaimed; ret = migrate_pages(&cc->migratepages, alloc_migration_target, NULL, (unsigned long)&mtc, cc->mode, MR_CONTIG_RANGE); /* * On -ENOMEM, migrate_pages() bails out right away. It is pointless * to retry again over this error, so do the same here. */ if (ret == -ENOMEM) break; } lru_cache_enable(); if (ret < 0) { alloc_contig_dump_pages(&cc->migratepages); putback_movable_pages(&cc->migratepages); return ret; } return 0; } /** * alloc_contig_range() -- tries to allocate given range of pages * @start: start PFN to allocate * @end: one-past-the-last PFN to allocate * @migratetype: migratetype of the underlying pageblocks (either * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks * in range must have the same migratetype and it must * be either of the two. * @gfp_mask: GFP mask to use during compaction * * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES * aligned. The PFN range must belong to a single zone. * * The first thing this routine does is attempt to MIGRATE_ISOLATE all * pageblocks in the range. Once isolated, the pageblocks should not * be modified by others. * * Return: zero on success or negative error code. On success all * pages which PFN is in [start, end) are allocated for the caller and * need to be freed with free_contig_range(). */ int alloc_contig_range(unsigned long start, unsigned long end, unsigned migratetype, gfp_t gfp_mask) { unsigned long outer_start, outer_end; unsigned int order; int ret = 0; struct compact_control cc = { .nr_migratepages = 0, .order = -1, .zone = page_zone(pfn_to_page(start)), .mode = MIGRATE_SYNC, .ignore_skip_hint = true, .no_set_skip_hint = true, .gfp_mask = current_gfp_context(gfp_mask), .alloc_contig = true, }; INIT_LIST_HEAD(&cc.migratepages); /* * What we do here is we mark all pageblocks in range as * MIGRATE_ISOLATE. Because pageblock and max order pages may * have different sizes, and due to the way page allocator * work, we align the range to biggest of the two pages so * that page allocator won't try to merge buddies from * different pageblocks and change MIGRATE_ISOLATE to some * other migration type. * * Once the pageblocks are marked as MIGRATE_ISOLATE, we * migrate the pages from an unaligned range (ie. pages that * we are interested in). This will put all the pages in * range back to page allocator as MIGRATE_ISOLATE. * * When this is done, we take the pages in range from page * allocator removing them from the buddy system. This way * page allocator will never consider using them. * * This lets us mark the pageblocks back as * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the * aligned range but not in the unaligned, original range are * put back to page allocator so that buddy can use them. */ ret = start_isolate_page_range(pfn_max_align_down(start), pfn_max_align_up(end), migratetype, 0); if (ret) return ret; drain_all_pages(cc.zone); /* * In case of -EBUSY, we'd like to know which page causes problem. * So, just fall through. test_pages_isolated() has a tracepoint * which will report the busy page. * * It is possible that busy pages could become available before * the call to test_pages_isolated, and the range will actually be * allocated. So, if we fall through be sure to clear ret so that * -EBUSY is not accidentally used or returned to caller. */ ret = __alloc_contig_migrate_range(&cc, start, end); if (ret && ret != -EBUSY) goto done; ret = 0; /* * Pages from [start, end) are within a MAX_ORDER_NR_PAGES * aligned blocks that are marked as MIGRATE_ISOLATE. What's * more, all pages in [start, end) are free in page allocator. * What we are going to do is to allocate all pages from * [start, end) (that is remove them from page allocator). * * The only problem is that pages at the beginning and at the * end of interesting range may be not aligned with pages that * page allocator holds, ie. they can be part of higher order * pages. Because of this, we reserve the bigger range and * once this is done free the pages we are not interested in. * * We don't have to hold zone->lock here because the pages are * isolated thus they won't get removed from buddy. */ order = 0; outer_start = start; while (!PageBuddy(pfn_to_page(outer_start))) { if (++order >= MAX_ORDER) { outer_start = start; break; } outer_start &= ~0UL << order; } if (outer_start != start) { order = buddy_order(pfn_to_page(outer_start)); /* * outer_start page could be small order buddy page and * it doesn't include start page. Adjust outer_start * in this case to report failed page properly * on tracepoint in test_pages_isolated() */ if (outer_start + (1UL << order) <= start) outer_start = start; } /* Make sure the range is really isolated. */ if (test_pages_isolated(outer_start, end, 0)) { ret = -EBUSY; goto done; } /* Grab isolated pages from freelists. */ outer_end = isolate_freepages_range(&cc, outer_start, end); if (!outer_end) { ret = -EBUSY; goto done; } /* Free head and tail (if any) */ if (start != outer_start) free_contig_range(outer_start, start - outer_start); if (end != outer_end) free_contig_range(end, outer_end - end); done: undo_isolate_page_range(pfn_max_align_down(start), pfn_max_align_up(end), migratetype); return ret; } EXPORT_SYMBOL(alloc_contig_range); static int __alloc_contig_pages(unsigned long start_pfn, unsigned long nr_pages, gfp_t gfp_mask) { unsigned long end_pfn = start_pfn + nr_pages; return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE, gfp_mask); } static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn, unsigned long nr_pages) { unsigned long i, end_pfn = start_pfn + nr_pages; struct page *page; for (i = start_pfn; i < end_pfn; i++) { page = pfn_to_online_page(i); if (!page) return false; if (page_zone(page) != z) return false; if (PageReserved(page)) return false; } return true; } static bool zone_spans_last_pfn(const struct zone *zone, unsigned long start_pfn, unsigned long nr_pages) { unsigned long last_pfn = start_pfn + nr_pages - 1; return zone_spans_pfn(zone, last_pfn); } /** * alloc_contig_pages() -- tries to find and allocate contiguous range of pages * @nr_pages: Number of contiguous pages to allocate * @gfp_mask: GFP mask to limit search and used during compaction * @nid: Target node * @nodemask: Mask for other possible nodes * * This routine is a wrapper around alloc_contig_range(). It scans over zones * on an applicable zonelist to find a contiguous pfn range which can then be * tried for allocation with alloc_contig_range(). This routine is intended * for allocation requests which can not be fulfilled with the buddy allocator. * * The allocated memory is always aligned to a page boundary. If nr_pages is a * power of two then the alignment is guaranteed to be to the given nr_pages * (e.g. 1GB request would be aligned to 1GB). * * Allocated pages can be freed with free_contig_range() or by manually calling * __free_page() on each allocated page. * * Return: pointer to contiguous pages on success, or NULL if not successful. */ struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask, int nid, nodemask_t *nodemask) { unsigned long ret, pfn, flags; struct zonelist *zonelist; struct zone *zone; struct zoneref *z; zonelist = node_zonelist(nid, gfp_mask); for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nodemask) { spin_lock_irqsave(&zone->lock, flags); pfn = ALIGN(zone->zone_start_pfn, nr_pages); while (zone_spans_last_pfn(zone, pfn, nr_pages)) { if (pfn_range_valid_contig(zone, pfn, nr_pages)) { /* * We release the zone lock here because * alloc_contig_range() will also lock the zone * at some point. If there's an allocation * spinning on this lock, it may win the race * and cause alloc_contig_range() to fail... */ spin_unlock_irqrestore(&zone->lock, flags); ret = __alloc_contig_pages(pfn, nr_pages, gfp_mask); if (!ret) return pfn_to_page(pfn); spin_lock_irqsave(&zone->lock, flags); } pfn += nr_pages; } spin_unlock_irqrestore(&zone->lock, flags); } return NULL; } #endif /* CONFIG_CONTIG_ALLOC */ void free_contig_range(unsigned long pfn, unsigned long nr_pages) { unsigned long count = 0; for (; nr_pages--; pfn++) { struct page *page = pfn_to_page(pfn); count += page_count(page) != 1; __free_page(page); } WARN(count != 0, "%lu pages are still in use!\n", count); } EXPORT_SYMBOL(free_contig_range); /* * The zone indicated has a new number of managed_pages; batch sizes and percpu * page high values need to be recalculated. */ void __meminit zone_pcp_update(struct zone *zone) { mutex_lock(&pcp_batch_high_lock); zone_set_pageset_high_and_batch(zone); mutex_unlock(&pcp_batch_high_lock); } /* * Effectively disable pcplists for the zone by setting the high limit to 0 * and draining all cpus. A concurrent page freeing on another CPU that's about * to put the page on pcplist will either finish before the drain and the page * will be drained, or observe the new high limit and skip the pcplist. * * Must be paired with a call to zone_pcp_enable(). */ void zone_pcp_disable(struct zone *zone) { mutex_lock(&pcp_batch_high_lock); __zone_set_pageset_high_and_batch(zone, 0, 1); __drain_all_pages(zone, true); } void zone_pcp_enable(struct zone *zone) { __zone_set_pageset_high_and_batch(zone, zone->pageset_high, zone->pageset_batch); mutex_unlock(&pcp_batch_high_lock); } void zone_pcp_reset(struct zone *zone) { int cpu; struct per_cpu_pageset *pset; if (zone->pageset != &boot_pageset) { for_each_online_cpu(cpu) { pset = per_cpu_ptr(zone->pageset, cpu); drain_zonestat(zone, pset); } free_percpu(zone->pageset); zone->pageset = &boot_pageset; } } #ifdef CONFIG_MEMORY_HOTREMOVE /* * All pages in the range must be in a single zone, must not contain holes, * must span full sections, and must be isolated before calling this function. */ void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn = start_pfn; struct page *page; struct zone *zone; unsigned int order; unsigned long flags; offline_mem_sections(pfn, end_pfn); zone = page_zone(pfn_to_page(pfn)); spin_lock_irqsave(&zone->lock, flags); while (pfn < end_pfn) { page = pfn_to_page(pfn); /* * The HWPoisoned page may be not in buddy system, and * page_count() is not 0. */ if (unlikely(!PageBuddy(page) && PageHWPoison(page))) { pfn++; continue; } /* * At this point all remaining PageOffline() pages have a * reference count of 0 and can simply be skipped. */ if (PageOffline(page)) { BUG_ON(page_count(page)); BUG_ON(PageBuddy(page)); pfn++; continue; } BUG_ON(page_count(page)); BUG_ON(!PageBuddy(page)); order = buddy_order(page); del_page_from_free_list(page, zone, order); pfn += (1 << order); } spin_unlock_irqrestore(&zone->lock, flags); } #endif bool is_free_buddy_page(struct page *page) { struct zone *zone = page_zone(page); unsigned long pfn = page_to_pfn(page); unsigned long flags; unsigned int order; spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { struct page *page_head = page - (pfn & ((1 << order) - 1)); if (PageBuddy(page_head) && buddy_order(page_head) >= order) break; } spin_unlock_irqrestore(&zone->lock, flags); return order < MAX_ORDER; } #ifdef CONFIG_MEMORY_FAILURE /* * Break down a higher-order page in sub-pages, and keep our target out of * buddy allocator. */ static void break_down_buddy_pages(struct zone *zone, struct page *page, struct page *target, int low, int high, int migratetype) { unsigned long size = 1 << high; struct page *current_buddy, *next_page; while (high > low) { high--; size >>= 1; if (target >= &page[size]) { next_page = page + size; current_buddy = page; } else { next_page = page; current_buddy = page + size; } if (set_page_guard(zone, current_buddy, high, migratetype)) continue; if (current_buddy != target) { add_to_free_list(current_buddy, zone, high, migratetype); set_buddy_order(current_buddy, high); page = next_page; } } } /* * Take a page that will be marked as poisoned off the buddy allocator. */ bool take_page_off_buddy(struct page *page) { struct zone *zone = page_zone(page); unsigned long pfn = page_to_pfn(page); unsigned long flags; unsigned int order; bool ret = false; spin_lock_irqsave(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { struct page *page_head = page - (pfn & ((1 << order) - 1)); int page_order = buddy_order(page_head); if (PageBuddy(page_head) && page_order >= order) { unsigned long pfn_head = page_to_pfn(page_head); int migratetype = get_pfnblock_migratetype(page_head, pfn_head); del_page_from_free_list(page_head, zone, page_order); break_down_buddy_pages(zone, page_head, page, 0, page_order, migratetype); ret = true; break; } if (page_count(page_head) > 0) break; } spin_unlock_irqrestore(&zone->lock, flags); return ret; } #endif