/* * 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 "internal.h" /* 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 #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_); int _node_numa_mem_[MAX_NUMNODES]; #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 #ifdef CONFIG_MOVABLE_NODE [N_MEMORY] = { { [0] = 1UL } }, #endif [N_CPU] = { { [0] = 1UL } }, #endif /* NUMA */ }; EXPORT_SYMBOL(node_states); /* Protect totalram_pages and zone->managed_pages */ static DEFINE_SPINLOCK(managed_page_count_lock); unsigned long totalram_pages __read_mostly; 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; /* * 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 pm_mutex held (gfp_allowed_mask also should * only be modified with pm_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(&pm_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(&pm_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); /* * 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-1] = { #ifdef CONFIG_ZONE_DMA 256, #endif #ifdef CONFIG_ZONE_DMA32 256, #endif #ifdef CONFIG_HIGHMEM 32, #endif 32, }; EXPORT_SYMBOL(totalram_pages); 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 }; compound_page_dtor * const compound_page_dtors[] = { NULL, free_compound_page, #ifdef CONFIG_HUGETLB_PAGE free_huge_page, #endif #ifdef CONFIG_TRANSPARENT_HUGEPAGE free_transhuge_page, #endif }; int min_free_kbytes = 1024; int user_min_free_kbytes = -1; static unsigned long __meminitdata nr_kernel_pages; static unsigned long __meminitdata nr_all_pages; static unsigned long __meminitdata dma_reserve; #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES]; static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES]; static unsigned long __initdata required_kernelcore; static unsigned long __initdata required_movablecore; static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES]; /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */ int movable_zone; EXPORT_SYMBOL(movable_zone); #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ #if MAX_NUMNODES > 1 int nr_node_ids __read_mostly = MAX_NUMNODES; 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 static inline void reset_deferred_meminit(pg_data_t *pgdat) { pgdat->first_deferred_pfn = ULONG_MAX; } /* Returns true if the struct page for the pfn is uninitialised */ static inline bool __meminit early_page_uninitialised(unsigned long pfn) { if (pfn >= NODE_DATA(early_pfn_to_nid(pfn))->first_deferred_pfn) return true; return false; } static inline bool early_page_nid_uninitialised(unsigned long pfn, int nid) { if (pfn >= NODE_DATA(nid)->first_deferred_pfn) return true; return false; } /* * Returns false when the remaining initialisation should be deferred until * later in the boot cycle when it can be parallelised. */ static inline bool update_defer_init(pg_data_t *pgdat, unsigned long pfn, unsigned long zone_end, unsigned long *nr_initialised) { /* Always populate low zones for address-contrained allocations */ if (zone_end < pgdat_end_pfn(pgdat)) return true; /* Initialise at least 2G of the highest zone */ (*nr_initialised)++; if (*nr_initialised > (2UL << (30 - PAGE_SHIFT)) && (pfn & (PAGES_PER_SECTION - 1)) == 0) { pgdat->first_deferred_pfn = pfn; return false; } return true; } #else static inline void reset_deferred_meminit(pg_data_t *pgdat) { } static inline bool early_page_uninitialised(unsigned long pfn) { return false; } static inline bool early_page_nid_uninitialised(unsigned long pfn, int nid) { return false; } static inline bool update_defer_init(pg_data_t *pgdat, unsigned long pfn, unsigned long zone_end, unsigned long *nr_initialised) { return true; } #endif void set_pageblock_migratetype(struct page *page, int migratetype) { if (unlikely(page_group_by_mobility_disabled && migratetype < MIGRATE_PCPTYPES)) migratetype = MIGRATE_UNMOVABLE; set_pageblock_flags_group(page, (unsigned long)migratetype, PB_migrate, PB_migrate_end); } #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 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 bad_range(struct zone *zone, struct page *page) { return 0; } #endif static void bad_page(struct page *page, const char *reason, unsigned long bad_flags) { static unsigned long resume; static unsigned long nr_shown; static unsigned long nr_unshown; /* Don't complain about poisoned pages */ if (PageHWPoison(page)) { page_mapcount_reset(page); /* remove PageBuddy */ return; } /* * 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) { printk(KERN_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; printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n", current->comm, page_to_pfn(page)); dump_page_badflags(page, reason, bad_flags); 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) { __free_pages_ok(page, compound_order(page)); } void prep_compound_page(struct page *page, unsigned int order) { int i; int nr_pages = 1 << order; set_compound_page_dtor(page, COMPOUND_PAGE_DTOR); set_compound_order(page, 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); } atomic_set(compound_mapcount_ptr(page), -1); } #ifdef CONFIG_DEBUG_PAGEALLOC unsigned int _debug_guardpage_minorder; bool _debug_pagealloc_enabled __read_mostly; bool _debug_guardpage_enabled __read_mostly; static int __init early_debug_pagealloc(char *buf) { if (!buf) return -EINVAL; if (strcmp(buf, "on") == 0) _debug_pagealloc_enabled = true; return 0; } early_param("debug_pagealloc", early_debug_pagealloc); static bool need_debug_guardpage(void) { /* If we don't use debug_pagealloc, we don't need guard page */ if (!debug_pagealloc_enabled()) return false; return true; } static void init_debug_guardpage(void) { if (!debug_pagealloc_enabled()) return; _debug_guardpage_enabled = true; } struct page_ext_operations debug_guardpage_ops = { .need = need_debug_guardpage, .init = init_debug_guardpage, }; static int __init debug_guardpage_minorder_setup(char *buf) { unsigned long res; if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) { printk(KERN_ERR "Bad debug_guardpage_minorder value\n"); return 0; } _debug_guardpage_minorder = res; printk(KERN_INFO "Setting debug_guardpage_minorder to %lu\n", res); return 0; } __setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup); static inline void set_page_guard(struct zone *zone, struct page *page, unsigned int order, int migratetype) { struct page_ext *page_ext; if (!debug_guardpage_enabled()) return; page_ext = lookup_page_ext(page); __set_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags); 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); } static inline void clear_page_guard(struct zone *zone, struct page *page, unsigned int order, int migratetype) { struct page_ext *page_ext; if (!debug_guardpage_enabled()) return; page_ext = lookup_page_ext(page); __clear_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags); set_page_private(page, 0); if (!is_migrate_isolate(migratetype)) __mod_zone_freepage_state(zone, (1 << order), migratetype); } #else struct page_ext_operations debug_guardpage_ops = { NULL, }; static inline void set_page_guard(struct zone *zone, struct page *page, unsigned int order, int migratetype) {} static inline void clear_page_guard(struct zone *zone, struct page *page, unsigned int order, int migratetype) {} #endif static inline void set_page_order(struct page *page, unsigned int order) { set_page_private(page, order); __SetPageBuddy(page); } static inline void rmv_page_order(struct page *page) { __ClearPageBuddy(page); set_page_private(page, 0); } /* * This function checks whether a page is free && is the buddy * we can do coalesce a page and its buddy if * (a) the buddy is not in a hole && * (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 ->_mapcount * PAGE_BUDDY_MAPCOUNT_VALUE. * Setting, clearing, and testing _mapcount PAGE_BUDDY_MAPCOUNT_VALUE is * serialized by zone->lock. * * For recording page's order, we use page_private(page). */ static inline int page_is_buddy(struct page *page, struct page *buddy, unsigned int order) { if (!pfn_valid_within(page_to_pfn(buddy))) return 0; if (page_is_guard(buddy) && page_order(buddy) == order) { if (page_zone_id(page) != page_zone_id(buddy)) return 0; VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); return 1; } if (PageBuddy(buddy) && page_order(buddy) == order) { /* * 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 0; VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); return 1; } return 0; } /* * 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 _mapcount * PAGE_BUDDY_MAPCOUNT_VALUE. 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) { unsigned long page_idx; unsigned long combined_idx; unsigned long uninitialized_var(buddy_idx); struct page *buddy; unsigned int max_order = MAX_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 (is_migrate_isolate(migratetype)) { /* * We restrict max order of merging to prevent merge * between freepages on isolate pageblock and normal * pageblock. Without this, pageblock isolation * could cause incorrect freepage accounting. */ max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1); } else { __mod_zone_freepage_state(zone, 1 << order, migratetype); } page_idx = pfn & ((1 << max_order) - 1); VM_BUG_ON_PAGE(page_idx & ((1 << order) - 1), page); VM_BUG_ON_PAGE(bad_range(zone, page), page); while (order < max_order - 1) { buddy_idx = __find_buddy_index(page_idx, order); buddy = page + (buddy_idx - page_idx); if (!page_is_buddy(page, buddy, order)) break; /* * 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 { list_del(&buddy->lru); zone->free_area[order].nr_free--; rmv_page_order(buddy); } combined_idx = buddy_idx & page_idx; page = page + (combined_idx - page_idx); page_idx = combined_idx; order++; } set_page_order(page, order); /* * 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 */ if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) { struct page *higher_page, *higher_buddy; combined_idx = buddy_idx & page_idx; higher_page = page + (combined_idx - page_idx); buddy_idx = __find_buddy_index(combined_idx, order + 1); higher_buddy = higher_page + (buddy_idx - combined_idx); if (page_is_buddy(higher_page, higher_buddy, order + 1)) { list_add_tail(&page->lru, &zone->free_area[order].free_list[migratetype]); goto out; } } list_add(&page->lru, &zone->free_area[order].free_list[migratetype]); out: zone->free_area[order].nr_free++; } static inline int free_pages_check(struct page *page) { const char *bad_reason = NULL; unsigned long bad_flags = 0; if (unlikely(atomic_read(&page->_mapcount) != -1)) bad_reason = "nonzero mapcount"; if (unlikely(page->mapping != NULL)) bad_reason = "non-NULL mapping"; if (unlikely(atomic_read(&page->_count) != 0)) bad_reason = "nonzero _count"; if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) { bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set"; bad_flags = PAGE_FLAGS_CHECK_AT_FREE; } #ifdef CONFIG_MEMCG if (unlikely(page->mem_cgroup)) bad_reason = "page still charged to cgroup"; #endif if (unlikely(bad_reason)) { bad_page(page, bad_reason, bad_flags); return 1; } page_cpupid_reset_last(page); if (page->flags & PAGE_FLAGS_CHECK_AT_PREP) page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; return 0; } /* * 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 to_free = count; unsigned long nr_scanned; spin_lock(&zone->lock); nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED); if (nr_scanned) __mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned); while (to_free) { struct page *page; 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 = to_free; do { int mt; /* migratetype of the to-be-freed page */ page = list_last_entry(list, struct page, lru); /* must delete as __free_one_page list manipulates */ list_del(&page->lru); 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(has_isolate_pageblock(zone))) mt = get_pageblock_migratetype(page); __free_one_page(page, page_to_pfn(page), zone, 0, mt); trace_mm_page_pcpu_drain(page, 0, mt); } while (--to_free && --batch_free && !list_empty(list)); } spin_unlock(&zone->lock); } static void free_one_page(struct zone *zone, struct page *page, unsigned long pfn, unsigned int order, int migratetype) { unsigned long nr_scanned; spin_lock(&zone->lock); nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED); if (nr_scanned) __mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned); if (unlikely(has_isolate_pageblock(zone) || is_migrate_isolate(migratetype))) { migratetype = get_pfnblock_migratetype(page, pfn); } __free_one_page(page, pfn, zone, order, migratetype); spin_unlock(&zone->lock); } 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 is compound_mapcount() */ if (unlikely(compound_mapcount(page))) { bad_page(page, "nonzero compound_mapcount", 0); goto out; } break; case 2: /* * the second tail page: ->mapping is * page_deferred_list().next -- ignore value. */ break; default: if (page->mapping != TAIL_MAPPING) { bad_page(page, "corrupted mapping in tail page", 0); goto out; } break; } if (unlikely(!PageTail(page))) { bad_page(page, "PageTail not set", 0); goto out; } if (unlikely(compound_head(page) != head_page)) { bad_page(page, "compound_head not consistent", 0); goto out; } ret = 0; out: page->mapping = NULL; clear_compound_head(page); return ret; } static void __meminit __init_single_page(struct page *page, unsigned long pfn, unsigned long zone, int nid) { set_page_links(page, zone, nid, pfn); init_page_count(page); page_mapcount_reset(page); page_cpupid_reset_last(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 } static void __meminit __init_single_pfn(unsigned long pfn, unsigned long zone, int nid) { return __init_single_page(pfn_to_page(pfn), pfn, zone, nid); } #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT static void 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_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(unsigned long start, unsigned long 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); SetPageReserved(page); } } } static bool free_pages_prepare(struct page *page, unsigned int order) { bool compound = PageCompound(page); int i, bad = 0; VM_BUG_ON_PAGE(PageTail(page), page); VM_BUG_ON_PAGE(compound && compound_order(page) != order, page); trace_mm_page_free(page, order); kmemcheck_free_shadow(page, order); kasan_free_pages(page, order); if (PageAnon(page)) page->mapping = NULL; bad += free_pages_check(page); for (i = 1; i < (1 << order); i++) { if (compound) bad += free_tail_pages_check(page, page + i); bad += free_pages_check(page + i); } if (bad) return false; 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); } arch_free_page(page, order); kernel_map_pages(page, 1 << order, 0); return true; } static void __free_pages_ok(struct page *page, unsigned int order) { unsigned long flags; int migratetype; unsigned long pfn = page_to_pfn(page); if (!free_pages_prepare(page, order)) 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); local_irq_restore(flags); } static void __init __free_pages_boot_core(struct page *page, unsigned long pfn, unsigned int order) { unsigned int nr_pages = 1 << order; struct page *p = page; unsigned int loop; 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); page_zone(page)->managed_pages += nr_pages; set_page_refcounted(page); __free_pages(page, order); } #if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \ defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata; 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 = 0; spin_unlock(&early_pfn_lock); return nid; } #endif #ifdef CONFIG_NODES_SPAN_OTHER_NODES static inline bool __meminit meminit_pfn_in_nid(unsigned long pfn, int node, struct mminit_pfnnid_cache *state) { int nid; nid = __early_pfn_to_nid(pfn, state); if (nid >= 0 && nid != node) return false; return true; } /* Only safe to use early in boot when initialisation is single-threaded */ static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node) { return meminit_pfn_in_nid(pfn, node, &early_pfnnid_cache); } #else static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node) { return true; } static inline bool __meminit meminit_pfn_in_nid(unsigned long pfn, int node, struct mminit_pfnnid_cache *state) { return true; } #endif void __init __free_pages_bootmem(struct page *page, unsigned long pfn, unsigned int order) { if (early_page_uninitialised(pfn)) return; return __free_pages_boot_core(page, pfn, order); } #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT static void __init deferred_free_range(struct page *page, unsigned long pfn, int nr_pages) { int i; if (!page) return; /* Free a large naturally-aligned chunk if possible */ if (nr_pages == MAX_ORDER_NR_PAGES && (pfn & (MAX_ORDER_NR_PAGES-1)) == 0) { set_pageblock_migratetype(page, MIGRATE_MOVABLE); __free_pages_boot_core(page, pfn, MAX_ORDER-1); return; } for (i = 0; i < nr_pages; i++, page++, pfn++) __free_pages_boot_core(page, pfn, 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); } /* Initialise remaining memory on a node */ static int __init deferred_init_memmap(void *data) { pg_data_t *pgdat = data; int nid = pgdat->node_id; struct mminit_pfnnid_cache nid_init_state = { }; unsigned long start = jiffies; unsigned long nr_pages = 0; unsigned long walk_start, walk_end; int i, zid; struct zone *zone; unsigned long first_init_pfn = pgdat->first_deferred_pfn; const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); if (first_init_pfn == ULONG_MAX) { pgdat_init_report_one_done(); return 0; } /* Bind memory initialisation thread to a local node if possible */ if (!cpumask_empty(cpumask)) set_cpus_allowed_ptr(current, cpumask); /* 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; /* 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; } for_each_mem_pfn_range(i, nid, &walk_start, &walk_end, NULL) { unsigned long pfn, end_pfn; struct page *page = NULL; struct page *free_base_page = NULL; unsigned long free_base_pfn = 0; int nr_to_free = 0; end_pfn = min(walk_end, zone_end_pfn(zone)); pfn = first_init_pfn; if (pfn < walk_start) pfn = walk_start; if (pfn < zone->zone_start_pfn) pfn = zone->zone_start_pfn; for (; pfn < end_pfn; pfn++) { if (!pfn_valid_within(pfn)) goto free_range; /* * Ensure pfn_valid is checked every * MAX_ORDER_NR_PAGES for memory holes */ if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) { if (!pfn_valid(pfn)) { page = NULL; goto free_range; } } if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state)) { page = NULL; goto free_range; } /* Minimise pfn page lookups and scheduler checks */ if (page && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) { page++; } else { nr_pages += nr_to_free; deferred_free_range(free_base_page, free_base_pfn, nr_to_free); free_base_page = NULL; free_base_pfn = nr_to_free = 0; page = pfn_to_page(pfn); cond_resched(); } if (page->flags) { VM_BUG_ON(page_zone(page) != zone); goto free_range; } __init_single_page(page, pfn, zid, nid); if (!free_base_page) { free_base_page = page; free_base_pfn = pfn; nr_to_free = 0; } nr_to_free++; /* Where possible, batch up pages for a single free */ continue; free_range: /* Free the current block of pages to allocator */ nr_pages += nr_to_free; deferred_free_range(free_base_page, free_base_pfn, nr_to_free); free_base_page = NULL; free_base_pfn = nr_to_free = 0; } first_init_pfn = max(end_pfn, first_init_pfn); } /* Sanity check that the next zone really is unpopulated */ WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone)); pr_info("node %d initialised, %lu pages in %ums\n", nid, nr_pages, jiffies_to_msecs(jiffies - start)); pgdat_init_report_one_done(); return 0; } void __init page_alloc_init_late(void) { int nid; /* 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); /* Reinit limits that are based on free pages after the kernel is up */ files_maxfiles_init(); } #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ #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); } #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, struct free_area *area, int migratetype) { unsigned long size = 1 << high; while (high > low) { area--; high--; size >>= 1; VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]); if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC) && debug_guardpage_enabled() && high < debug_guardpage_minorder()) { /* * 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 */ set_page_guard(zone, &page[size], high, migratetype); continue; } list_add(&page[size].lru, &area->free_list[migratetype]); area->nr_free++; set_page_order(&page[size], high); } } /* * This page is about to be returned from the page allocator */ static inline int check_new_page(struct page *page) { const char *bad_reason = NULL; unsigned long bad_flags = 0; if (unlikely(atomic_read(&page->_mapcount) != -1)) bad_reason = "nonzero mapcount"; if (unlikely(page->mapping != NULL)) bad_reason = "non-NULL mapping"; if (unlikely(atomic_read(&page->_count) != 0)) bad_reason = "nonzero _count"; if (unlikely(page->flags & __PG_HWPOISON)) { bad_reason = "HWPoisoned (hardware-corrupted)"; bad_flags = __PG_HWPOISON; } if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) { bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set"; bad_flags = PAGE_FLAGS_CHECK_AT_PREP; } #ifdef CONFIG_MEMCG if (unlikely(page->mem_cgroup)) bad_reason = "page still charged to cgroup"; #endif if (unlikely(bad_reason)) { bad_page(page, bad_reason, bad_flags); return 1; } return 0; } static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags, int alloc_flags) { int i; for (i = 0; i < (1 << order); i++) { struct page *p = page + i; if (unlikely(check_new_page(p))) return 1; } set_page_private(page, 0); set_page_refcounted(page); arch_alloc_page(page, order); kernel_map_pages(page, 1 << order, 1); kasan_alloc_pages(page, order); if (gfp_flags & __GFP_ZERO) for (i = 0; i < (1 << order); i++) clear_highpage(page + i); if (order && (gfp_flags & __GFP_COMP)) prep_compound_page(page, order); set_page_owner(page, order, gfp_flags); /* * 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); return 0; } /* * Go through the free lists for the given migratetype and remove * the smallest available page from the freelists */ static 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 = list_first_entry_or_null(&area->free_list[migratetype], struct page, lru); if (!page) continue; list_del(&page->lru); rmv_page_order(page); area->nr_free--; expand(zone, page, order, current_order, area, 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][4] = { [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, 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 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 free lists 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() */ int move_freepages(struct zone *zone, struct page *start_page, struct page *end_page, int migratetype) { struct page *page; unsigned int order; int pages_moved = 0; #ifndef CONFIG_HOLES_IN_ZONE /* * page_zone is not safe to call in this context when * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant * anyway as we check zone boundaries in move_freepages_block(). * Remove at a later date when no bug reports exist related to * grouping pages by mobility */ VM_BUG_ON(page_zone(start_page) != page_zone(end_page)); #endif for (page = start_page; page <= end_page;) { /* Make sure we are not inadvertently changing nodes */ VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); if (!pfn_valid_within(page_to_pfn(page))) { page++; continue; } if (!PageBuddy(page)) { page++; continue; } order = page_order(page); list_move(&page->lru, &zone->free_area[order].free_list[migratetype]); page += 1 << order; pages_moved += 1 << order; } return pages_moved; } int move_freepages_block(struct zone *zone, struct page *page, int migratetype) { unsigned long start_pfn, end_pfn; struct page *start_page, *end_page; start_pfn = page_to_pfn(page); start_pfn = start_pfn & ~(pageblock_nr_pages-1); start_page = pfn_to_page(start_pfn); end_page = start_page + 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_page = page; if (!zone_spans_pfn(zone, end_pfn)) return 0; return move_freepages(zone, start_page, end_page, migratetype); } 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; } /* * 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 and check whether half of pages are moved or not. If half of * pages are moved, we can change migratetype of pageblock and permanently * use it's pages as requested migratetype in the future. */ static void steal_suitable_fallback(struct zone *zone, struct page *page, int start_type) { unsigned int current_order = page_order(page); int pages; /* Take ownership for orders >= pageblock_order */ if (current_order >= pageblock_order) { change_pageblock_range(page, current_order, start_type); return; } pages = move_freepages_block(zone, page, start_type); /* Claim the whole block if over half of it is free */ if (pages >= (1 << (pageblock_order-1)) || page_group_by_mobility_disabled) set_pageblock_migratetype(page, 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 (list_empty(&area->free_list[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 / 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 (mt != MIGRATE_HIGHATOMIC && !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); } 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. */ static void unreserve_highatomic_pageblock(const struct alloc_context *ac) { struct zonelist *zonelist = ac->zonelist; unsigned long flags; struct zoneref *z; struct zone *zone; struct page *page; int order; for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->high_zoneidx, ac->nodemask) { /* Preserve at least one pageblock */ if (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 = list_first_entry_or_null( &area->free_list[MIGRATE_HIGHATOMIC], struct page, lru); if (!page) continue; /* * 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); move_freepages_block(zone, page, ac->migratetype); spin_unlock_irqrestore(&zone->lock, flags); return; } spin_unlock_irqrestore(&zone->lock, flags); } } /* Remove an element from the buddy allocator from the fallback list */ static inline struct page * __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype) { struct free_area *area; unsigned int current_order; struct page *page; int fallback_mt; bool can_steal; /* Find the largest possible block of pages in the other list */ for (current_order = MAX_ORDER-1; current_order >= order && current_order <= MAX_ORDER-1; --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; page = list_first_entry(&area->free_list[fallback_mt], struct page, lru); if (can_steal) steal_suitable_fallback(zone, page, start_migratetype); /* Remove the page from the freelists */ area->nr_free--; list_del(&page->lru); rmv_page_order(page); expand(zone, page, order, current_order, area, start_migratetype); /* * The pcppage_migratetype may differ from pageblock's * migratetype depending on the decisions in * find_suitable_fallback(). This is OK as long as it does not * differ for MIGRATE_CMA pageblocks. Those can be used as * fallback only via special __rmqueue_cma_fallback() function */ set_pcppage_migratetype(page, start_migratetype); trace_mm_page_alloc_extfrag(page, order, current_order, start_migratetype, fallback_mt); return page; } return NULL; } /* * Do the hard work of removing an element from the buddy allocator. * Call me with the zone->lock already held. */ static struct page *__rmqueue(struct zone *zone, unsigned int order, int migratetype) { struct page *page; page = __rmqueue_smallest(zone, order, migratetype); if (unlikely(!page)) { if (migratetype == MIGRATE_MOVABLE) page = __rmqueue_cma_fallback(zone, order); if (!page) page = __rmqueue_fallback(zone, order, migratetype); } 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, bool cold) { int i; spin_lock(&zone->lock); for (i = 0; i < count; ++i) { struct page *page = __rmqueue(zone, order, migratetype); if (unlikely(page == NULL)) break; /* * Split buddy pages returned by expand() are received here * in physical page order. The page is added to the callers and * list and the list head then moves forward. From the callers * perspective, the linked list is ordered by page number in * some conditions. This is useful for IO devices that can * merge IO requests if the physical pages are ordered * properly. */ if (likely(!cold)) list_add(&page->lru, list); else list_add_tail(&page->lru, list); list = &page->lru; if (is_migrate_cma(get_pcppage_migratetype(page))) __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, -(1 << order)); } __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order)); spin_unlock(&zone->lock); return i; } #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); pcp->count -= to_drain; } 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); pcp->count = 0; } 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); } /* * 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 code is protected against sending an IPI to an offline * CPU but does not guarantee sending an IPI to newly hotplugged CPUs: * on_each_cpu_mask() blocks hotplug and won't talk to offlined CPUs but * nothing keeps CPUs from showing up after we populated the cpumask and * before the call to on_each_cpu_mask(). */ void drain_all_pages(struct zone *zone) { 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; /* * 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 (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); } on_each_cpu_mask(&cpus_with_pcps, (smp_call_func_t) drain_local_pages, zone, 1); } #ifdef CONFIG_HIBERNATION void mark_free_pages(struct zone *zone) { unsigned long pfn, max_zone_pfn; 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 (!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++) swsusp_set_page_free(pfn_to_page(pfn + i)); } } spin_unlock_irqrestore(&zone->lock, flags); } #endif /* CONFIG_PM */ /* * Free a 0-order page * cold == true ? free a cold page : free a hot page */ void free_hot_cold_page(struct page *page, bool cold) { struct zone *zone = page_zone(page); struct per_cpu_pages *pcp; unsigned long flags; unsigned long pfn = page_to_pfn(page); int migratetype; if (!free_pages_prepare(page, 0)) return; migratetype = get_pfnblock_migratetype(page, pfn); set_pcppage_migratetype(page, migratetype); local_irq_save(flags); __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 RESERVE 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); goto out; } migratetype = MIGRATE_MOVABLE; } pcp = &this_cpu_ptr(zone->pageset)->pcp; if (!cold) list_add(&page->lru, &pcp->lists[migratetype]); else list_add_tail(&page->lru, &pcp->lists[migratetype]); pcp->count++; if (pcp->count >= pcp->high) { unsigned long batch = READ_ONCE(pcp->batch); free_pcppages_bulk(zone, batch, pcp); pcp->count -= batch; } out: local_irq_restore(flags); } /* * Free a list of 0-order pages */ void free_hot_cold_page_list(struct list_head *list, bool cold) { struct page *page, *next; list_for_each_entry_safe(page, next, list, lru) { trace_mm_page_free_batched(page, cold); free_hot_cold_page(page, cold); } } /* * split_page takes a non-compound higher-order page, and splits it into * n (1<lru); zone->free_area[order].nr_free--; rmv_page_order(page); set_page_owner(page, order, __GFP_MOVABLE); /* Set the pageblock if the isolated page is at least 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)) set_pageblock_migratetype(page, MIGRATE_MOVABLE); } } return 1UL << order; } /* * Similar to split_page except the page is already free. As this is only * being used for migration, the migratetype of the block also changes. * As this is called with interrupts disabled, the caller is responsible * for calling arch_alloc_page() and kernel_map_page() after interrupts * are enabled. * * Note: this is probably too low level an operation for use in drivers. * Please consult with lkml before using this in your driver. */ int split_free_page(struct page *page) { unsigned int order; int nr_pages; order = page_order(page); nr_pages = __isolate_free_page(page, order); if (!nr_pages) return 0; /* Split into individual pages */ set_page_refcounted(page); split_page(page, order); return nr_pages; } /* * Allocate a page from the given zone. Use pcplists for order-0 allocations. */ static inline struct page *buffered_rmqueue(struct zone *preferred_zone, struct zone *zone, unsigned int order, gfp_t gfp_flags, int alloc_flags, int migratetype) { unsigned long flags; struct page *page; bool cold = ((gfp_flags & __GFP_COLD) != 0); if (likely(order == 0)) { struct per_cpu_pages *pcp; struct list_head *list; local_irq_save(flags); pcp = &this_cpu_ptr(zone->pageset)->pcp; list = &pcp->lists[migratetype]; if (list_empty(list)) { pcp->count += rmqueue_bulk(zone, 0, pcp->batch, list, migratetype, cold); if (unlikely(list_empty(list))) goto failed; } if (cold) page = list_last_entry(list, struct page, lru); else page = list_first_entry(list, struct page, lru); list_del(&page->lru); pcp->count--; } else { if (unlikely(gfp_flags & __GFP_NOFAIL)) { /* * __GFP_NOFAIL is not to be used in new code. * * All __GFP_NOFAIL callers should be fixed so that they * properly detect and handle allocation failures. * * We most definitely don't want callers attempting to * allocate greater than order-1 page units with * __GFP_NOFAIL. */ WARN_ON_ONCE(order > 1); } spin_lock_irqsave(&zone->lock, flags); page = NULL; if (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); spin_unlock(&zone->lock); if (!page) goto failed; __mod_zone_freepage_state(zone, -(1 << order), get_pcppage_migratetype(page)); } __mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order)); if (atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH]) <= 0 && !test_bit(ZONE_FAIR_DEPLETED, &zone->flags)) set_bit(ZONE_FAIR_DEPLETED, &zone->flags); __count_zone_vm_events(PGALLOC, zone, 1 << order); zone_statistics(preferred_zone, zone, gfp_flags); local_irq_restore(flags); VM_BUG_ON_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 | S_IRUSR | S_IWUSR; struct dentry *dir; dir = fault_create_debugfs_attr("fail_page_alloc", NULL, &fail_page_alloc.attr); if (IS_ERR(dir)) return PTR_ERR(dir); if (!debugfs_create_bool("ignore-gfp-wait", mode, dir, &fail_page_alloc.ignore_gfp_reclaim)) goto fail; if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir, &fail_page_alloc.ignore_gfp_highmem)) goto fail; if (!debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order)) goto fail; return 0; fail: debugfs_remove_recursive(dir); return -ENOMEM; } 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 */ /* * 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. */ static bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, int classzone_idx, int alloc_flags, long free_pages) { long min = mark; int o; const int alloc_harder = (alloc_flags & ALLOC_HARDER); /* free_pages may go negative - that's OK */ free_pages -= (1 << order) - 1; if (alloc_flags & ALLOC_HIGH) min -= min / 2; /* * 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)) free_pages -= z->nr_reserved_highatomic; else min -= min / 4; #ifdef CONFIG_CMA /* If allocation can't use CMA areas don't use free CMA pages */ if (!(alloc_flags & ALLOC_CMA)) free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES); #endif /* * 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[classzone_idx]) 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; if (alloc_harder) return true; for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) { if (!list_empty(&area->free_list[mt])) return true; } #ifdef CONFIG_CMA if ((alloc_flags & ALLOC_CMA) && !list_empty(&area->free_list[MIGRATE_CMA])) { return true; } #endif } return false; } bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, int classzone_idx, int alloc_flags) { return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags, zone_page_state(z, NR_FREE_PAGES)); } bool zone_watermark_ok_safe(struct zone *z, unsigned int order, unsigned long mark, int classzone_idx) { 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, classzone_idx, 0, free_pages); } #ifdef CONFIG_NUMA static bool zone_local(struct zone *local_zone, struct zone *zone) { return local_zone->node == zone->node; } static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) { return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) < RECLAIM_DISTANCE; } #else /* CONFIG_NUMA */ static bool zone_local(struct zone *local_zone, struct zone *zone) { return true; } static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) { return true; } #endif /* CONFIG_NUMA */ static void reset_alloc_batches(struct zone *preferred_zone) { struct zone *zone = preferred_zone->zone_pgdat->node_zones; do { mod_zone_page_state(zone, NR_ALLOC_BATCH, high_wmark_pages(zone) - low_wmark_pages(zone) - atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH])); clear_bit(ZONE_FAIR_DEPLETED, &zone->flags); } while (zone++ != preferred_zone); } /* * 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 zonelist *zonelist = ac->zonelist; struct zoneref *z; struct page *page = NULL; struct zone *zone; int nr_fair_skipped = 0; bool zonelist_rescan; zonelist_scan: zonelist_rescan = false; /* * Scan zonelist, looking for a zone with enough free. * See also __cpuset_node_allowed() comment in kernel/cpuset.c. */ for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->high_zoneidx, ac->nodemask) { unsigned long mark; if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) && !cpuset_zone_allowed(zone, gfp_mask)) continue; /* * Distribute pages in proportion to the individual * zone size to ensure fair page aging. The zone a * page was allocated in should have no effect on the * time the page has in memory before being reclaimed. */ if (alloc_flags & ALLOC_FAIR) { if (!zone_local(ac->preferred_zone, zone)) break; if (test_bit(ZONE_FAIR_DEPLETED, &zone->flags)) { nr_fair_skipped++; continue; } } /* * When allocating a page cache page for writing, we * want to get it from a zone that is within its dirty * limit, such that no single zone holds more than its * proportional share of globally allowed dirty pages. * The dirty limits take into account the zone's * lowmem reserves and high watermark so that kswapd * should be able to balance it without having to * write pages from its LRU list. * * This may look like it could increase pressure on * lower zones by failing allocations in higher zones * before they are full. But the pages that do spill * over are limited as the lower zones are protected * by this very same mechanism. It should not become * a practical burden to them. * * XXX: For now, allow allocations to potentially * exceed the per-zone dirty limit in the slowpath * (spread_dirty_pages unset) before going into reclaim, * which is important when on a NUMA setup the allowed * zones are together not big enough to reach the * global limit. The proper fix for these situations * will require awareness of zones in the * dirty-throttling and the flusher threads. */ if (ac->spread_dirty_pages && !zone_dirty_ok(zone)) continue; mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK]; if (!zone_watermark_ok(zone, order, mark, ac->classzone_idx, alloc_flags)) { int ret; /* 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 (zone_reclaim_mode == 0 || !zone_allows_reclaim(ac->preferred_zone, zone)) continue; ret = zone_reclaim(zone, gfp_mask, order); switch (ret) { case ZONE_RECLAIM_NOSCAN: /* did not scan */ continue; case ZONE_RECLAIM_FULL: /* scanned but unreclaimable */ continue; default: /* did we reclaim enough */ if (zone_watermark_ok(zone, order, mark, ac->classzone_idx, alloc_flags)) goto try_this_zone; continue; } } try_this_zone: page = buffered_rmqueue(ac->preferred_zone, zone, order, gfp_mask, alloc_flags, ac->migratetype); if (page) { if (prep_new_page(page, order, gfp_mask, alloc_flags)) goto try_this_zone; /* * 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; } } /* * The first pass makes sure allocations are spread fairly within the * local node. However, the local node might have free pages left * after the fairness batches are exhausted, and remote zones haven't * even been considered yet. Try once more without fairness, and * include remote zones now, before entering the slowpath and waking * kswapd: prefer spilling to a remote zone over swapping locally. */ if (alloc_flags & ALLOC_FAIR) { alloc_flags &= ~ALLOC_FAIR; if (nr_fair_skipped) { zonelist_rescan = true; reset_alloc_batches(ac->preferred_zone); } if (nr_online_nodes > 1) zonelist_rescan = true; } if (zonelist_rescan) goto zonelist_scan; return NULL; } /* * Large machines with many possible nodes should not always dump per-node * meminfo in irq context. */ static inline bool should_suppress_show_mem(void) { bool ret = false; #if NODES_SHIFT > 8 ret = in_interrupt(); #endif return ret; } static DEFINE_RATELIMIT_STATE(nopage_rs, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); void warn_alloc_failed(gfp_t gfp_mask, unsigned int order, const char *fmt, ...) { unsigned int filter = SHOW_MEM_FILTER_NODES; if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) || debug_guardpage_minorder() > 0) return; /* * 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 (test_thread_flag(TIF_MEMDIE) || (current->flags & (PF_MEMALLOC | PF_EXITING))) filter &= ~SHOW_MEM_FILTER_NODES; if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM)) filter &= ~SHOW_MEM_FILTER_NODES; if (fmt) { struct va_format vaf; va_list args; va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; pr_warn("%pV", &vaf); va_end(args); } pr_warn("%s: page allocation failure: order:%u, mode:0x%x\n", current->comm, order, gfp_mask); dump_stack(); if (!should_suppress_show_mem()) show_mem(filter); } 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, .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. */ page = get_page_from_freelist(gfp_mask | __GFP_HARDWALL, order, ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac); if (page) goto out; if (!(gfp_mask & __GFP_NOFAIL)) { /* 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; /* The OOM killer does not needlessly kill tasks for lowmem */ if (ac->high_zoneidx < ZONE_NORMAL) goto out; /* The OOM killer does not compensate for IO-less reclaim */ if (!(gfp_mask & __GFP_FS)) { /* * XXX: Page reclaim didn't yield anything, * and the OOM killer can't be invoked, but * keep looping as per tradition. */ *did_some_progress = 1; goto out; } if (pm_suspended_storage()) goto out; /* The OOM killer may not free memory on a specific node */ if (gfp_mask & __GFP_THISNODE) goto out; } /* Exhausted what can be done so it's blamo time */ if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) { *did_some_progress = 1; if (gfp_mask & __GFP_NOFAIL) { page = get_page_from_freelist(gfp_mask, order, ALLOC_NO_WATERMARKS|ALLOC_CPUSET, ac); /* * fallback to ignore cpuset restriction if our nodes * are depleted */ if (!page) page = get_page_from_freelist(gfp_mask, order, ALLOC_NO_WATERMARKS, ac); } } out: mutex_unlock(&oom_lock); return page; } #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, int alloc_flags, const struct alloc_context *ac, enum migrate_mode mode, int *contended_compaction, bool *deferred_compaction) { unsigned long compact_result; struct page *page; if (!order) return NULL; current->flags |= PF_MEMALLOC; compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac, mode, contended_compaction); current->flags &= ~PF_MEMALLOC; switch (compact_result) { case COMPACT_DEFERRED: *deferred_compaction = true; /* fall-through */ case COMPACT_SKIPPED: return NULL; default: break; } /* * At least in one zone compaction wasn't deferred or skipped, so let's * count a compaction stall */ count_vm_event(COMPACTSTALL); page = get_page_from_freelist(gfp_mask, order, alloc_flags & ~ALLOC_NO_WATERMARKS, 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; } #else static inline struct page * __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, int alloc_flags, const struct alloc_context *ac, enum migrate_mode mode, int *contended_compaction, bool *deferred_compaction) { return NULL; } #endif /* CONFIG_COMPACTION */ /* Perform direct synchronous page reclaim */ static int __perform_reclaim(gfp_t gfp_mask, unsigned int order, const struct alloc_context *ac) { struct reclaim_state reclaim_state; int progress; cond_resched(); /* We now go into synchronous reclaim */ cpuset_memory_pressure_bump(); current->flags |= PF_MEMALLOC; lockdep_set_current_reclaim_state(gfp_mask); reclaim_state.reclaimed_slab = 0; current->reclaim_state = &reclaim_state; progress = try_to_free_pages(ac->zonelist, order, gfp_mask, ac->nodemask); current->reclaim_state = NULL; lockdep_clear_current_reclaim_state(); current->flags &= ~PF_MEMALLOC; 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, 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 & ~ALLOC_NO_WATERMARKS, 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 them and try again */ if (!page && !drained) { unreserve_highatomic_pageblock(ac); drain_all_pages(NULL); drained = true; goto retry; } return page; } static void wake_all_kswapds(unsigned int order, const struct alloc_context *ac) { struct zoneref *z; struct zone *zone; for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx, ac->nodemask) wakeup_kswapd(zone, order, zone_idx(ac->preferred_zone)); } static inline int gfp_to_alloc_flags(gfp_t gfp_mask) { int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET; /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */ BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH); /* * 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); 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; if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) { if (gfp_mask & __GFP_MEMALLOC) alloc_flags |= ALLOC_NO_WATERMARKS; else if (in_serving_softirq() && (current->flags & PF_MEMALLOC)) alloc_flags |= ALLOC_NO_WATERMARKS; else if (!in_interrupt() && ((current->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE)))) alloc_flags |= ALLOC_NO_WATERMARKS; } #ifdef CONFIG_CMA if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE) alloc_flags |= ALLOC_CMA; #endif return alloc_flags; } bool gfp_pfmemalloc_allowed(gfp_t gfp_mask) { return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_NO_WATERMARKS); } static inline bool is_thp_gfp_mask(gfp_t gfp_mask) { return (gfp_mask & (GFP_TRANSHUGE | __GFP_KSWAPD_RECLAIM)) == GFP_TRANSHUGE; } 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; struct page *page = NULL; int alloc_flags; unsigned long pages_reclaimed = 0; unsigned long did_some_progress; enum migrate_mode migration_mode = MIGRATE_ASYNC; bool deferred_compaction = false; int contended_compaction = COMPACT_CONTENDED_NONE; /* * In the slowpath, we sanity check order to avoid ever trying to * reclaim >= MAX_ORDER areas which will never succeed. Callers may * be using allocators in order of preference for an area that is * too large. */ if (order >= MAX_ORDER) { WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN)); return NULL; } /* * 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; /* * If this allocation cannot block and it is for a specific node, then * fail early. There's no need to wakeup kswapd or retry for a * speculative node-specific allocation. */ if (IS_ENABLED(CONFIG_NUMA) && (gfp_mask & __GFP_THISNODE) && !can_direct_reclaim) goto nopage; retry: if (gfp_mask & __GFP_KSWAPD_RECLAIM) wake_all_kswapds(order, ac); /* * OK, we're below the kswapd watermark and have kicked background * reclaim. Now things get more complex, so set up alloc_flags according * to how we want to proceed. */ alloc_flags = gfp_to_alloc_flags(gfp_mask); /* * Find the true preferred zone if the allocation is unconstrained by * cpusets. */ if (!(alloc_flags & ALLOC_CPUSET) && !ac->nodemask) { struct zoneref *preferred_zoneref; preferred_zoneref = first_zones_zonelist(ac->zonelist, ac->high_zoneidx, NULL, &ac->preferred_zone); ac->classzone_idx = zonelist_zone_idx(preferred_zoneref); } /* This is the last chance, in general, before the goto nopage. */ page = get_page_from_freelist(gfp_mask, order, alloc_flags & ~ALLOC_NO_WATERMARKS, ac); if (page) goto got_pg; /* Allocate without watermarks if the context allows */ if (alloc_flags & ALLOC_NO_WATERMARKS) { /* * Ignore mempolicies if ALLOC_NO_WATERMARKS on the grounds * the allocation is high priority and these type of * allocations are system rather than user orientated */ ac->zonelist = node_zonelist(numa_node_id(), gfp_mask); page = get_page_from_freelist(gfp_mask, order, ALLOC_NO_WATERMARKS, ac); if (page) goto got_pg; } /* Caller is not willing to reclaim, we can't balance anything */ if (!can_direct_reclaim) { /* * All existing users of the __GFP_NOFAIL are blockable, so warn * of any new users that actually allow this type of allocation * to fail. */ WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL); goto nopage; } /* Avoid recursion of direct reclaim */ if (current->flags & PF_MEMALLOC) { /* * __GFP_NOFAIL 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. */ if (WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) { cond_resched(); goto retry; } goto nopage; } /* Avoid allocations with no watermarks from looping endlessly */ if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL)) goto nopage; /* * Try direct compaction. The first pass is asynchronous. Subsequent * attempts after direct reclaim are synchronous */ page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, migration_mode, &contended_compaction, &deferred_compaction); if (page) goto got_pg; /* Checks for THP-specific high-order allocations */ if (is_thp_gfp_mask(gfp_mask)) { /* * If compaction is deferred for high-order allocations, it is * because sync compaction recently failed. If this is the case * and the caller requested a THP allocation, we do not want * to heavily disrupt the system, so we fail the allocation * instead of entering direct reclaim. */ if (deferred_compaction) goto nopage; /* * In all zones where compaction was attempted (and not * deferred or skipped), lock contention has been detected. * For THP allocation we do not want to disrupt the others * so we fallback to base pages instead. */ if (contended_compaction == COMPACT_CONTENDED_LOCK) goto nopage; /* * If compaction was aborted due to need_resched(), we do not * want to further increase allocation latency, unless it is * khugepaged trying to collapse. */ if (contended_compaction == COMPACT_CONTENDED_SCHED && !(current->flags & PF_KTHREAD)) goto nopage; } /* * It can become very expensive to allocate transparent hugepages at * fault, so use asynchronous memory compaction for THP unless it is * khugepaged trying to collapse. */ if (!is_thp_gfp_mask(gfp_mask) || (current->flags & PF_KTHREAD)) migration_mode = MIGRATE_SYNC_LIGHT; /* 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; /* Do not loop if specifically requested */ if (gfp_mask & __GFP_NORETRY) goto noretry; /* Keep reclaiming pages as long as there is reasonable progress */ pages_reclaimed += did_some_progress; if ((did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER) || ((gfp_mask & __GFP_REPEAT) && pages_reclaimed < (1 << order))) { /* Wait for some write requests to complete then retry */ wait_iff_congested(ac->preferred_zone, BLK_RW_ASYNC, HZ/50); goto retry; } /* Reclaim has failed us, start killing things */ page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress); if (page) goto got_pg; /* Retry as long as the OOM killer is making progress */ if (did_some_progress) goto retry; noretry: /* * High-order allocations do not necessarily loop after * direct reclaim and reclaim/compaction depends on compaction * being called after reclaim so call directly if necessary */ page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac, migration_mode, &contended_compaction, &deferred_compaction); if (page) goto got_pg; nopage: warn_alloc_failed(gfp_mask, order, NULL); got_pg: return page; } /* * This is the 'heart' of the zoned buddy allocator. */ struct page * __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, struct zonelist *zonelist, nodemask_t *nodemask) { struct zoneref *preferred_zoneref; struct page *page = NULL; unsigned int cpuset_mems_cookie; int alloc_flags = ALLOC_WMARK_LOW|ALLOC_CPUSET|ALLOC_FAIR; gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */ struct alloc_context ac = { .high_zoneidx = gfp_zone(gfp_mask), .nodemask = nodemask, .migratetype = gfpflags_to_migratetype(gfp_mask), }; gfp_mask &= gfp_allowed_mask; lockdep_trace_alloc(gfp_mask); might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM); if (should_fail_alloc_page(gfp_mask, order)) return NULL; /* * Check the zones suitable for the gfp_mask contain at least one * valid zone. It's possible to have an empty zonelist as a result * of __GFP_THISNODE and a memoryless node */ if (unlikely(!zonelist->_zonerefs->zone)) return NULL; if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE) alloc_flags |= ALLOC_CMA; retry_cpuset: cpuset_mems_cookie = read_mems_allowed_begin(); /* We set it here, as __alloc_pages_slowpath might have changed it */ ac.zonelist = zonelist; /* Dirty zone balancing only done in the fast path */ ac.spread_dirty_pages = (gfp_mask & __GFP_WRITE); /* The preferred zone is used for statistics later */ preferred_zoneref = first_zones_zonelist(ac.zonelist, ac.high_zoneidx, ac.nodemask ? : &cpuset_current_mems_allowed, &ac.preferred_zone); if (!ac.preferred_zone) goto out; ac.classzone_idx = zonelist_zone_idx(preferred_zoneref); /* First allocation attempt */ alloc_mask = gfp_mask|__GFP_HARDWALL; page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac); if (unlikely(!page)) { /* * Runtime PM, block IO and its error handling path * can deadlock because I/O on the device might not * complete. */ alloc_mask = memalloc_noio_flags(gfp_mask); ac.spread_dirty_pages = false; page = __alloc_pages_slowpath(alloc_mask, order, &ac); } if (kmemcheck_enabled && page) kmemcheck_pagealloc_alloc(page, order, gfp_mask); trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype); out: /* * When updating a task's mems_allowed, it is possible to race with * parallel threads in such a way that an allocation can fail while * the mask is being updated. If a page allocation is about to fail, * check if the cpuset changed during allocation and if so, retry. */ if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie))) goto retry_cpuset; return page; } EXPORT_SYMBOL(__alloc_pages_nodemask); /* * Common helper functions. */ unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order) { struct page *page; /* * __get_free_pages() returns a 32-bit address, which cannot represent * a highmem page */ VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0); page = alloc_pages(gfp_mask, 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); void __free_pages(struct page *page, unsigned int order) { if (put_page_testzero(page)) { if (order == 0) free_hot_cold_page(page, false); else __free_pages_ok(page, 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_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 *__alloc_page_frag(struct page_frag_cache *nc, unsigned int fragsz, gfp_t gfp_mask) { unsigned int size = PAGE_SIZE; struct page *page; int offset; if (unlikely(!nc->va)) { refill: page = __page_frag_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. */ atomic_add(size - 1, &page->_count); /* reset page count bias and offset to start of new frag */ nc->pfmemalloc = page_is_pfmemalloc(page); nc->pagecnt_bias = size; nc->offset = size; } offset = nc->offset - fragsz; if (unlikely(offset < 0)) { page = virt_to_page(nc->va); if (!atomic_sub_and_test(nc->pagecnt_bias, &page->_count)) 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 */ atomic_set(&page->_count, size); /* reset page count bias and offset to start of new frag */ nc->pagecnt_bias = size; offset = size - fragsz; } nc->pagecnt_bias--; nc->offset = offset; return nc->va + offset; } EXPORT_SYMBOL(__alloc_page_frag); /* * Frees a page fragment allocated out of either a compound or order 0 page. */ void __free_page_frag(void *addr) { struct page *page = virt_to_head_page(addr); if (unlikely(put_page_testzero(page))) __free_pages_ok(page, compound_order(page)); } EXPORT_SYMBOL(__free_page_frag); /* * alloc_kmem_pages charges newly allocated pages to the kmem resource counter * of the current memory cgroup if __GFP_ACCOUNT is set, other than that it is * equivalent to alloc_pages. * * It should be used when the caller would like to use kmalloc, but since the * allocation is large, it has to fall back to the page allocator. */ struct page *alloc_kmem_pages(gfp_t gfp_mask, unsigned int order) { struct page *page; page = alloc_pages(gfp_mask, order); if (page && memcg_kmem_charge(page, gfp_mask, order) != 0) { __free_pages(page, order); page = NULL; } return page; } struct page *alloc_kmem_pages_node(int nid, gfp_t gfp_mask, unsigned int order) { struct page *page; page = alloc_pages_node(nid, gfp_mask, order); if (page && memcg_kmem_charge(page, gfp_mask, order) != 0) { __free_pages(page, order); page = NULL; } return page; } /* * __free_kmem_pages and free_kmem_pages will free pages allocated with * alloc_kmem_pages. */ void __free_kmem_pages(struct page *page, unsigned int order) { memcg_kmem_uncharge(page, order); __free_pages(page, order); } void free_kmem_pages(unsigned long addr, unsigned int order) { if (addr != 0) { VM_BUG_ON(!virt_addr_valid((void *)addr)); __free_kmem_pages(virt_to_page((void *)addr), order); } } 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 * * 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(). */ void *alloc_pages_exact(size_t size, gfp_t gfp_mask) { unsigned int order = get_order(size); unsigned long addr; 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 * * Like alloc_pages_exact(), but try to allocate on node nid first before falling * back. */ void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask) { unsigned int order = get_order(size); struct page *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 counts 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: * managed_pages - high_pages */ 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; 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. */ unsigned long nr_free_buffer_pages(void) { return nr_free_zone_pages(gfp_zone(GFP_USER)); } EXPORT_SYMBOL_GPL(nr_free_buffer_pages); /** * nr_free_pagecache_pages - count number of pages beyond high watermark * * nr_free_pagecache_pages() counts the number of pages which are beyond the * high watermark within all zones. */ unsigned long nr_free_pagecache_pages(void) { return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE)); } static inline void show_node(struct zone *zone) { if (IS_ENABLED(CONFIG_NUMA)) printk("Node %d ", zone_to_nid(zone)); } void si_meminfo(struct sysinfo *val) { val->totalram = totalram_pages; val->sharedram = global_page_state(NR_SHMEM); val->freeram = global_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; pg_data_t *pgdat = NODE_DATA(nid); for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) managed_pages += pgdat->node_zones[zone_type].managed_pages; val->totalram = managed_pages; val->sharedram = node_page_state(nid, NR_SHMEM); val->freeram = node_page_state(nid, NR_FREE_PAGES); #ifdef CONFIG_HIGHMEM val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].managed_pages; val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM], NR_FREE_PAGES); #else val->totalhigh = 0; val->freehigh = 0; #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(). */ bool skip_free_areas_node(unsigned int flags, int nid) { bool ret = false; unsigned int cpuset_mems_cookie; if (!(flags & SHOW_MEM_FILTER_NODES)) goto out; do { cpuset_mems_cookie = read_mems_allowed_begin(); ret = !node_isset(nid, cpuset_current_mems_allowed); } while (read_mems_allowed_retry(cpuset_mems_cookie)); out: return ret; } #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("(%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) { unsigned long free_pcp = 0; int cpu; struct zone *zone; for_each_populated_zone(zone) { if (skip_free_areas_node(filter, zone_to_nid(zone))) 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 unstable:%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_page_state(NR_ACTIVE_ANON), global_page_state(NR_INACTIVE_ANON), global_page_state(NR_ISOLATED_ANON), global_page_state(NR_ACTIVE_FILE), global_page_state(NR_INACTIVE_FILE), global_page_state(NR_ISOLATED_FILE), global_page_state(NR_UNEVICTABLE), global_page_state(NR_FILE_DIRTY), global_page_state(NR_WRITEBACK), global_page_state(NR_UNSTABLE_NFS), global_page_state(NR_SLAB_RECLAIMABLE), global_page_state(NR_SLAB_UNRECLAIMABLE), global_page_state(NR_FILE_MAPPED), global_page_state(NR_SHMEM), global_page_state(NR_PAGETABLE), global_page_state(NR_BOUNCE), global_page_state(NR_FREE_PAGES), free_pcp, global_page_state(NR_FREE_CMA_PAGES)); for_each_populated_zone(zone) { int i; if (skip_free_areas_node(filter, zone_to_nid(zone))) continue; free_pcp = 0; for_each_online_cpu(cpu) free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count; show_node(zone); printk("%s" " free:%lukB" " min:%lukB" " low:%lukB" " high:%lukB" " active_anon:%lukB" " inactive_anon:%lukB" " active_file:%lukB" " inactive_file:%lukB" " unevictable:%lukB" " isolated(anon):%lukB" " isolated(file):%lukB" " present:%lukB" " managed:%lukB" " mlocked:%lukB" " dirty:%lukB" " writeback:%lukB" " mapped:%lukB" " shmem:%lukB" " slab_reclaimable:%lukB" " slab_unreclaimable:%lukB" " kernel_stack:%lukB" " pagetables:%lukB" " unstable:%lukB" " bounce:%lukB" " free_pcp:%lukB" " local_pcp:%ukB" " free_cma:%lukB" " writeback_tmp:%lukB" " pages_scanned:%lu" " all_unreclaimable? %s" "\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_page_state(zone, NR_ACTIVE_ANON)), K(zone_page_state(zone, NR_INACTIVE_ANON)), K(zone_page_state(zone, NR_ACTIVE_FILE)), K(zone_page_state(zone, NR_INACTIVE_FILE)), K(zone_page_state(zone, NR_UNEVICTABLE)), K(zone_page_state(zone, NR_ISOLATED_ANON)), K(zone_page_state(zone, NR_ISOLATED_FILE)), K(zone->present_pages), K(zone->managed_pages), K(zone_page_state(zone, NR_MLOCK)), K(zone_page_state(zone, NR_FILE_DIRTY)), K(zone_page_state(zone, NR_WRITEBACK)), K(zone_page_state(zone, NR_FILE_MAPPED)), K(zone_page_state(zone, NR_SHMEM)), K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)), K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)), zone_page_state(zone, NR_KERNEL_STACK) * THREAD_SIZE / 1024, K(zone_page_state(zone, NR_PAGETABLE)), K(zone_page_state(zone, NR_UNSTABLE_NFS)), 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)), K(zone_page_state(zone, NR_WRITEBACK_TEMP)), K(zone_page_state(zone, NR_PAGES_SCANNED)), (!zone_reclaimable(zone) ? "yes" : "no") ); printk("lowmem_reserve[]:"); for (i = 0; i < MAX_NR_ZONES; i++) printk(" %ld", zone->lowmem_reserve[i]); printk("\n"); } for_each_populated_zone(zone) { unsigned int order; unsigned long nr[MAX_ORDER], flags, total = 0; unsigned char types[MAX_ORDER]; if (skip_free_areas_node(filter, zone_to_nid(zone))) continue; show_node(zone); printk("%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 (!list_empty(&area->free_list[type])) types[order] |= 1 << type; } } spin_unlock_irqrestore(&zone->lock, flags); for (order = 0; order < MAX_ORDER; order++) { printk("%lu*%lukB ", nr[order], K(1UL) << order); if (nr[order]) show_migration_types(types[order]); } printk("= %lukB\n", K(total)); } hugetlb_show_meminfo(); printk("%ld total pagecache pages\n", global_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_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist, int nr_zones) { struct zone *zone; enum zone_type zone_type = MAX_NR_ZONES; do { zone_type--; zone = pgdat->node_zones + zone_type; if (populated_zone(zone)) { zoneref_set_zone(zone, &zonelist->_zonerefs[nr_zones++]); check_highest_zone(zone_type); } } while (zone_type); return nr_zones; } /* * zonelist_order: * 0 = automatic detection of better ordering. * 1 = order by ([node] distance, -zonetype) * 2 = order by (-zonetype, [node] distance) * * If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create * the same zonelist. So only NUMA can configure this param. */ #define ZONELIST_ORDER_DEFAULT 0 #define ZONELIST_ORDER_NODE 1 #define ZONELIST_ORDER_ZONE 2 /* zonelist order in the kernel. * set_zonelist_order() will set this to NODE or ZONE. */ static int current_zonelist_order = ZONELIST_ORDER_DEFAULT; static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"}; #ifdef CONFIG_NUMA /* The value user specified ....changed by config */ static int user_zonelist_order = ZONELIST_ORDER_DEFAULT; /* string for sysctl */ #define NUMA_ZONELIST_ORDER_LEN 16 char numa_zonelist_order[16] = "default"; /* * interface for configure zonelist ordering. * command line option "numa_zonelist_order" * = "[dD]efault - default, automatic configuration. * = "[nN]ode - order by node locality, then by zone within node * = "[zZ]one - order by zone, then by locality within zone */ static int __parse_numa_zonelist_order(char *s) { if (*s == 'd' || *s == 'D') { user_zonelist_order = ZONELIST_ORDER_DEFAULT; } else if (*s == 'n' || *s == 'N') { user_zonelist_order = ZONELIST_ORDER_NODE; } else if (*s == 'z' || *s == 'Z') { user_zonelist_order = ZONELIST_ORDER_ZONE; } else { printk(KERN_WARNING "Ignoring invalid numa_zonelist_order value: " "%s\n", s); return -EINVAL; } return 0; } static __init int setup_numa_zonelist_order(char *s) { int ret; if (!s) return 0; ret = __parse_numa_zonelist_order(s); if (ret == 0) strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN); return ret; } early_param("numa_zonelist_order", setup_numa_zonelist_order); /* * sysctl handler for numa_zonelist_order */ int numa_zonelist_order_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { char saved_string[NUMA_ZONELIST_ORDER_LEN]; int ret; static DEFINE_MUTEX(zl_order_mutex); mutex_lock(&zl_order_mutex); if (write) { if (strlen((char *)table->data) >= NUMA_ZONELIST_ORDER_LEN) { ret = -EINVAL; goto out; } strcpy(saved_string, (char *)table->data); } ret = proc_dostring(table, write, buffer, length, ppos); if (ret) goto out; if (write) { int oldval = user_zonelist_order; ret = __parse_numa_zonelist_order((char *)table->data); if (ret) { /* * bogus value. restore saved string */ strncpy((char *)table->data, saved_string, NUMA_ZONELIST_ORDER_LEN); user_zonelist_order = oldval; } else if (oldval != user_zonelist_order) { mutex_lock(&zonelists_mutex); build_all_zonelists(NULL, NULL); mutex_unlock(&zonelists_mutex); } } out: mutex_unlock(&zl_order_mutex); return ret; } #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. * It returns -1 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; const struct cpumask *tmp = cpumask_of_node(0); /* 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 */ tmp = cpumask_of_node(n); if (!cpumask_empty(tmp)) 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) { int j; struct zonelist *zonelist; zonelist = &pgdat->node_zonelists[0]; for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++) ; j = build_zonelists_node(NODE_DATA(node), zonelist, j); zonelist->_zonerefs[j].zone = NULL; zonelist->_zonerefs[j].zone_idx = 0; } /* * Build gfp_thisnode zonelists */ static void build_thisnode_zonelists(pg_data_t *pgdat) { int j; struct zonelist *zonelist; zonelist = &pgdat->node_zonelists[1]; j = build_zonelists_node(pgdat, zonelist, 0); zonelist->_zonerefs[j].zone = NULL; zonelist->_zonerefs[j].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 int node_order[MAX_NUMNODES]; static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes) { int pos, j, node; int zone_type; /* needs to be signed */ struct zone *z; struct zonelist *zonelist; zonelist = &pgdat->node_zonelists[0]; pos = 0; for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) { for (j = 0; j < nr_nodes; j++) { node = node_order[j]; z = &NODE_DATA(node)->node_zones[zone_type]; if (populated_zone(z)) { zoneref_set_zone(z, &zonelist->_zonerefs[pos++]); check_highest_zone(zone_type); } } } zonelist->_zonerefs[pos].zone = NULL; zonelist->_zonerefs[pos].zone_idx = 0; } #if defined(CONFIG_64BIT) /* * Devices that require DMA32/DMA are relatively rare and do not justify a * penalty to every machine in case the specialised case applies. Default * to Node-ordering on 64-bit NUMA machines */ static int default_zonelist_order(void) { return ZONELIST_ORDER_NODE; } #else /* * On 32-bit, the Normal zone needs to be preserved for allocations accessible * by the kernel. If processes running on node 0 deplete the low memory zone * then reclaim will occur more frequency increasing stalls and potentially * be easier to OOM if a large percentage of the zone is under writeback or * dirty. The problem is significantly worse if CONFIG_HIGHPTE is not set. * Hence, default to zone ordering on 32-bit. */ static int default_zonelist_order(void) { return ZONELIST_ORDER_ZONE; } #endif /* CONFIG_64BIT */ static void set_zonelist_order(void) { if (user_zonelist_order == ZONELIST_ORDER_DEFAULT) current_zonelist_order = default_zonelist_order(); else current_zonelist_order = user_zonelist_order; } static void build_zonelists(pg_data_t *pgdat) { int i, node, load; nodemask_t used_mask; int local_node, prev_node; struct zonelist *zonelist; unsigned int order = current_zonelist_order; /* initialize zonelists */ for (i = 0; i < MAX_ZONELISTS; i++) { zonelist = pgdat->node_zonelists + i; zonelist->_zonerefs[0].zone = NULL; zonelist->_zonerefs[0].zone_idx = 0; } /* NUMA-aware ordering of nodes */ local_node = pgdat->node_id; load = nr_online_nodes; prev_node = local_node; nodes_clear(used_mask); memset(node_order, 0, sizeof(node_order)); i = 0; 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; prev_node = node; load--; if (order == ZONELIST_ORDER_NODE) build_zonelists_in_node_order(pgdat, node); else node_order[i++] = node; /* remember order */ } if (order == ZONELIST_ORDER_ZONE) { /* calculate node order -- i.e., DMA last! */ build_zonelists_in_zone_order(pgdat, i); } 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 zone *zone; (void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL), gfp_zone(GFP_KERNEL), NULL, &zone); return zone->node; } #endif #else /* CONFIG_NUMA */ static void set_zonelist_order(void) { current_zonelist_order = ZONELIST_ORDER_ZONE; } static void build_zonelists(pg_data_t *pgdat) { int node, local_node; enum zone_type j; struct zonelist *zonelist; local_node = pgdat->node_id; zonelist = &pgdat->node_zonelists[0]; j = build_zonelists_node(pgdat, zonelist, 0); /* * 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; j = build_zonelists_node(NODE_DATA(node), zonelist, j); } for (node = 0; node < local_node; node++) { if (!node_online(node)) continue; j = build_zonelists_node(NODE_DATA(node), zonelist, j); } zonelist->_zonerefs[j].zone = NULL; zonelist->_zonerefs[j].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 setup_pageset(struct per_cpu_pageset *p, unsigned long batch); static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset); static void setup_zone_pageset(struct zone *zone); /* * Global mutex to protect against size modification of zonelists * as well as to serialize pageset setup for the new populated zone. */ DEFINE_MUTEX(zonelists_mutex); /* return values int ....just for stop_machine() */ static int __build_all_zonelists(void *data) { int nid; int cpu; pg_data_t *self = data; #ifdef CONFIG_NUMA memset(node_load, 0, sizeof(node_load)); #endif if (self && !node_online(self->node_id)) { build_zonelists(self); } for_each_online_node(nid) { pg_data_t *pgdat = NODE_DATA(nid); build_zonelists(pgdat); } /* * 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) { setup_pageset(&per_cpu(boot_pageset, cpu), 0); #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. */ if (cpu_online(cpu)) set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu))); #endif } return 0; } static noinline void __init build_all_zonelists_init(void) { __build_all_zonelists(NULL); mminit_verify_zonelist(); cpuset_init_current_mems_allowed(); } /* * Called with zonelists_mutex held always * unless system_state == SYSTEM_BOOTING. * * __ref due to (1) call of __meminit annotated setup_zone_pageset * [we're only called with non-NULL zone through __meminit paths] and * (2) call of __init annotated helper build_all_zonelists_init * [protected by SYSTEM_BOOTING]. */ void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone) { set_zonelist_order(); if (system_state == SYSTEM_BOOTING) { build_all_zonelists_init(); } else { #ifdef CONFIG_MEMORY_HOTPLUG if (zone) setup_zone_pageset(zone); #endif /* we have to stop all cpus to guarantee there is no user of zonelist */ stop_machine(__build_all_zonelists, pgdat, NULL); /* cpuset refresh routine should be here */ } vm_total_pages = nr_free_pagecache_pages(); /* * 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 %i zonelists in %s order, mobility grouping %s. " "Total pages: %ld\n", nr_online_nodes, zonelist_order_name[current_zonelist_order], page_group_by_mobility_disabled ? "off" : "on", vm_total_pages); #ifdef CONFIG_NUMA pr_info("Policy zone: %s\n", zone_names[policy_zone]); #endif } /* * Helper functions to size the waitqueue hash table. * Essentially these want to choose hash table sizes sufficiently * large so that collisions trying to wait on pages are rare. * But in fact, the number of active page waitqueues on typical * systems is ridiculously low, less than 200. So this is even * conservative, even though it seems large. * * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to * waitqueues, i.e. the size of the waitq table given the number of pages. */ #define PAGES_PER_WAITQUEUE 256 #ifndef CONFIG_MEMORY_HOTPLUG static inline unsigned long wait_table_hash_nr_entries(unsigned long pages) { unsigned long size = 1; pages /= PAGES_PER_WAITQUEUE; while (size < pages) size <<= 1; /* * Once we have dozens or even hundreds of threads sleeping * on IO we've got bigger problems than wait queue collision. * Limit the size of the wait table to a reasonable size. */ size = min(size, 4096UL); return max(size, 4UL); } #else /* * A zone's size might be changed by hot-add, so it is not possible to determine * a suitable size for its wait_table. So we use the maximum size now. * * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie: * * i386 (preemption config) : 4096 x 16 = 64Kbyte. * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte. * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte. * * The maximum entries are prepared when a zone's memory is (512K + 256) pages * or more by the traditional way. (See above). It equals: * * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte. * ia64(16K page size) : = ( 8G + 4M)byte. * powerpc (64K page size) : = (32G +16M)byte. */ static inline unsigned long wait_table_hash_nr_entries(unsigned long pages) { return 4096UL; } #endif /* * This is an integer logarithm so that shifts can be used later * to extract the more random high bits from the multiplicative * hash function before the remainder is taken. */ static inline unsigned long wait_table_bits(unsigned long size) { return ffz(~size); } /* * Initially all pages are reserved - free ones are freed * up by free_all_bootmem() once the early boot process is * done. Non-atomic initialization, single-pass. */ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, unsigned long start_pfn, enum memmap_context context) { struct vmem_altmap *altmap = to_vmem_altmap(__pfn_to_phys(start_pfn)); unsigned long end_pfn = start_pfn + size; pg_data_t *pgdat = NODE_DATA(nid); unsigned long pfn; unsigned long nr_initialised = 0; if (highest_memmap_pfn < end_pfn - 1) highest_memmap_pfn = end_pfn - 1; /* * Honor reservation requested by the driver for this ZONE_DEVICE * memory */ if (altmap && start_pfn == altmap->base_pfn) start_pfn += altmap->reserve; for (pfn = start_pfn; pfn < end_pfn; pfn++) { /* * There can be holes in boot-time mem_map[]s * handed to this function. They do not * exist on hotplugged memory. */ if (context == MEMMAP_EARLY) { if (!early_pfn_valid(pfn)) continue; if (!early_pfn_in_nid(pfn, nid)) continue; if (!update_defer_init(pgdat, pfn, end_pfn, &nr_initialised)) break; } /* * 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. * * bitmap is created for zone's valid pfn range. but memmap * can be created for invalid pages (for alignment) * check here not to call set_pageblock_migratetype() against * pfn out of zone. */ if (!(pfn & (pageblock_nr_pages - 1))) { struct page *page = pfn_to_page(pfn); __init_single_page(page, pfn, zone, nid); set_pageblock_migratetype(page, MIGRATE_MOVABLE); } else { __init_single_pfn(pfn, zone, nid); } } } 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; } } #ifndef __HAVE_ARCH_MEMMAP_INIT #define memmap_init(size, nid, zone, start_pfn) \ memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY) #endif 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. But no more than 1/2 of a meg. * * OK, so we don't know how big the cache is. So guess. */ batch = zone->managed_pages / 1024; if (batch * PAGE_SIZE > 512 * 1024) batch = (512 * 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 dependent on one another: * ->batch must never be higher then ->high. * The following function updates them in a safe manner without read side * locking. * * Any new users of pcp->batch and pcp->high should ensure they can cope with * those fields changing asynchronously (acording the the above rule). * * 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) { /* start with a fail safe value for batch */ pcp->batch = 1; smp_wmb(); /* Update high, then batch, in order */ pcp->high = high; smp_wmb(); pcp->batch = batch; } /* a companion to pageset_set_high() */ static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch) { pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch)); } static void pageset_init(struct per_cpu_pageset *p) { struct per_cpu_pages *pcp; int migratetype; memset(p, 0, sizeof(*p)); pcp = &p->pcp; pcp->count = 0; for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++) INIT_LIST_HEAD(&pcp->lists[migratetype]); } static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch) { pageset_init(p); pageset_set_batch(p, batch); } /* * pageset_set_high() sets the high water mark for hot per_cpu_pagelist * to the value high for the pageset p. */ static void pageset_set_high(struct per_cpu_pageset *p, unsigned long high) { unsigned long batch = max(1UL, high / 4); if ((high / 4) > (PAGE_SHIFT * 8)) batch = PAGE_SHIFT * 8; pageset_update(&p->pcp, high, batch); } static void pageset_set_high_and_batch(struct zone *zone, struct per_cpu_pageset *pcp) { if (percpu_pagelist_fraction) pageset_set_high(pcp, (zone->managed_pages / percpu_pagelist_fraction)); else pageset_set_batch(pcp, zone_batchsize(zone)); } static void __meminit zone_pageset_init(struct zone *zone, int cpu) { struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu); pageset_init(pcp); pageset_set_high_and_batch(zone, pcp); } static void __meminit setup_zone_pageset(struct zone *zone) { int cpu; zone->pageset = alloc_percpu(struct per_cpu_pageset); for_each_possible_cpu(cpu) zone_pageset_init(zone, cpu); } /* * Allocate per cpu pagesets and initialize them. * Before this call only boot pagesets were available. */ void __init setup_per_cpu_pageset(void) { struct zone *zone; for_each_populated_zone(zone) setup_zone_pageset(zone); } static noinline __init_refok int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages) { int i; size_t alloc_size; /* * The per-page waitqueue mechanism uses hashed waitqueues * per zone. */ zone->wait_table_hash_nr_entries = wait_table_hash_nr_entries(zone_size_pages); zone->wait_table_bits = wait_table_bits(zone->wait_table_hash_nr_entries); alloc_size = zone->wait_table_hash_nr_entries * sizeof(wait_queue_head_t); if (!slab_is_available()) { zone->wait_table = (wait_queue_head_t *) memblock_virt_alloc_node_nopanic( alloc_size, zone->zone_pgdat->node_id); } else { /* * This case means that a zone whose size was 0 gets new memory * via memory hot-add. * But it may be the case that a new node was hot-added. In * this case vmalloc() will not be able to use this new node's * memory - this wait_table must be initialized to use this new * node itself as well. * To use this new node's memory, further consideration will be * necessary. */ zone->wait_table = vmalloc(alloc_size); } if (!zone->wait_table) return -ENOMEM; for (i = 0; i < zone->wait_table_hash_nr_entries; ++i) init_waitqueue_head(zone->wait_table + i); return 0; } 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; if (populated_zone(zone)) printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n", zone->name, zone->present_pages, zone_batchsize(zone)); } int __meminit init_currently_empty_zone(struct zone *zone, unsigned long zone_start_pfn, unsigned long size) { struct pglist_data *pgdat = zone->zone_pgdat; int ret; ret = zone_wait_table_init(zone, size); if (ret) return ret; pgdat->nr_zones = zone_idx(zone) + 1; 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); return 0; } #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID /* * Required by SPARSEMEM. Given a PFN, return what node the PFN is on. */ 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 != -1) { state->last_start = start_pfn; state->last_end = end_pfn; state->last_nid = nid; } return nid; } #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */ /** * free_bootmem_with_active_regions - Call memblock_free_early_nid for each active range * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed. * @max_low_pfn: The highest PFN that will be passed to memblock_free_early_nid * * If an architecture guarantees that all ranges registered contain no holes * and may be freed, this this function may be used instead of calling * memblock_free_early_nid() manually. */ void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn) { unsigned long start_pfn, end_pfn; int i, this_nid; for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) { start_pfn = min(start_pfn, max_low_pfn); end_pfn = min(end_pfn, max_low_pfn); if (start_pfn < end_pfn) memblock_free_early_nid(PFN_PHYS(start_pfn), (end_pfn - start_pfn) << PAGE_SHIFT, this_nid); } } /** * sparse_memory_present_with_active_regions - Call memory_present for each active range * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used. * * If an architecture guarantees that all ranges registered contain no holes and may * be freed, this function may be used instead of calling memory_present() manually. */ void __init sparse_memory_present_with_active_regions(int nid) { unsigned long start_pfn, end_pfn; int i, this_nid; for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) memory_present(this_nid, start_pfn, end_pfn); } /** * 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 __meminit 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 __meminit 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 (*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 __meminit zone_spanned_pages_in_node(int nid, unsigned long zone_type, unsigned long node_start_pfn, unsigned long node_end_pfn, unsigned long *ignored) { unsigned long zone_start_pfn, zone_end_pfn; /* 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 = arch_zone_lowest_possible_pfn[zone_type]; zone_end_pfn = arch_zone_highest_possible_pfn[zone_type]; 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 __meminit __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 * * It returns 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 __meminit zone_absent_pages_in_node(int nid, unsigned long zone_type, unsigned long node_start_pfn, unsigned long node_end_pfn, unsigned long *ignored) { 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; /* 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); return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn); } #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ static inline unsigned long __meminit zone_spanned_pages_in_node(int nid, unsigned long zone_type, unsigned long node_start_pfn, unsigned long node_end_pfn, unsigned long *zones_size) { return zones_size[zone_type]; } static inline unsigned long __meminit zone_absent_pages_in_node(int nid, unsigned long zone_type, unsigned long node_start_pfn, unsigned long node_end_pfn, unsigned long *zholes_size) { if (!zholes_size) return 0; return zholes_size[zone_type]; } #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ static void __meminit calculate_node_totalpages(struct pglist_data *pgdat, unsigned long node_start_pfn, unsigned long node_end_pfn, unsigned long *zones_size, unsigned long *zholes_size) { 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 size, real_size; size = zone_spanned_pages_in_node(pgdat->node_id, i, node_start_pfn, node_end_pfn, zones_size); real_size = size - zone_absent_pages_in_node(pgdat->node_id, i, node_start_pfn, node_end_pfn, zholes_size); 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 __init setup_usemap(struct pglist_data *pgdat, struct zone *zone, unsigned long zone_start_pfn, unsigned long zonesize) { unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize); zone->pageblock_flags = NULL; if (usemapsize) zone->pageblock_flags = memblock_virt_alloc_node_nopanic(usemapsize, pgdat->node_id); } #else static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone, unsigned long zone_start_pfn, unsigned long zonesize) {} #endif /* CONFIG_SPARSEMEM */ #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */ void __paginginit 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 __paginginit set_pageblock_order(void) { } #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */ static unsigned long __paginginit 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 naturally algined 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; } /* * 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. */ static void __paginginit free_area_init_core(struct pglist_data *pgdat) { enum zone_type j; int nid = pgdat->node_id; unsigned long zone_start_pfn = pgdat->node_start_pfn; int ret; pgdat_resize_init(pgdat); #ifdef CONFIG_NUMA_BALANCING spin_lock_init(&pgdat->numabalancing_migrate_lock); pgdat->numabalancing_migrate_nr_pages = 0; pgdat->numabalancing_migrate_next_window = jiffies; #endif #ifdef CONFIG_TRANSPARENT_HUGEPAGE spin_lock_init(&pgdat->split_queue_lock); INIT_LIST_HEAD(&pgdat->split_queue); pgdat->split_queue_len = 0; #endif init_waitqueue_head(&pgdat->kswapd_wait); init_waitqueue_head(&pgdat->pfmemalloc_wait); pgdat_page_ext_init(pgdat); for (j = 0; j < MAX_NR_ZONES; j++) { struct zone *zone = pgdat->node_zones + j; unsigned long size, realsize, freesize, memmap_pages; size = zone->spanned_pages; realsize = 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, realsize); 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 printk(KERN_WARNING " %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->managed_pages = is_highmem_idx(j) ? realsize : freesize; #ifdef CONFIG_NUMA zone->node = nid; zone->min_unmapped_pages = (freesize*sysctl_min_unmapped_ratio) / 100; zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100; #endif zone->name = zone_names[j]; spin_lock_init(&zone->lock); spin_lock_init(&zone->lru_lock); zone_seqlock_init(zone); zone->zone_pgdat = pgdat; zone_pcp_init(zone); /* For bootup, initialized properly in watermark setup */ mod_zone_page_state(zone, NR_ALLOC_BATCH, zone->managed_pages); lruvec_init(&zone->lruvec); if (!size) continue; set_pageblock_order(); setup_usemap(pgdat, zone, zone_start_pfn, size); ret = init_currently_empty_zone(zone, zone_start_pfn, size); BUG_ON(ret); memmap_init(size, nid, j, zone_start_pfn); zone_start_pfn += size; } } static void __init_refok 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; #ifdef CONFIG_FLAT_NODE_MEM_MAP 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 = alloc_remap(pgdat->node_id, size); if (!map) map = memblock_virt_alloc_node_nopanic(size, pgdat->node_id); pgdat->node_mem_map = map + offset; } #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 defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM) if (page_to_pfn(mem_map) != pgdat->node_start_pfn) mem_map -= offset; #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ } #endif #endif /* CONFIG_FLAT_NODE_MEM_MAP */ } void __paginginit free_area_init_node(int nid, unsigned long *zones_size, unsigned long node_start_pfn, unsigned long *zholes_size) { 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->classzone_idx); reset_deferred_meminit(pgdat); pgdat->node_id = nid; pgdat->node_start_pfn = node_start_pfn; #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP get_pfn_range_for_nid(nid, &start_pfn, &end_pfn); 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); #endif calculate_node_totalpages(pgdat, start_pfn, end_pfn, zones_size, zholes_size); alloc_node_mem_map(pgdat); #ifdef CONFIG_FLAT_NODE_MEM_MAP printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n", nid, (unsigned long)pgdat, (unsigned long)pgdat->node_mem_map); #endif free_area_init_core(pgdat); } #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP #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. * * Returns 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 = -1; 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 the lowest pfn for a node */ static unsigned long __init find_min_pfn_for_node(int nid) { unsigned long min_pfn = ULONG_MAX; unsigned long start_pfn; int i; for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL) min_pfn = min(min_pfn, start_pfn); if (min_pfn == ULONG_MAX) { printk(KERN_WARNING "Could not find start_pfn for node %d\n", nid); return 0; } return min_pfn; } /** * find_min_pfn_with_active_regions - Find the minimum PFN registered * * It returns the minimum PFN based on information provided via * memblock_set_node(). */ unsigned long __init find_min_pfn_with_active_regions(void) { return find_min_pfn_for_node(MAX_NUMNODES); } /* * 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_memblock(memory, r) { if (!memblock_is_hotpluggable(r)) continue; nid = r->nid; 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 movablecore=nn[KMG] 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; if (N_MEMORY == N_NORMAL_MEMORY) return; for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) { struct zone *zone = &pgdat->node_zones[zone_type]; if (populated_zone(zone)) { node_set_state(nid, N_HIGH_MEMORY); if (N_NORMAL_MEMORY != N_HIGH_MEMORY && zone_type <= ZONE_NORMAL) node_set_state(nid, N_NORMAL_MEMORY); break; } } } /** * free_area_init_nodes - 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_nodes(unsigned long *max_zone_pfn) { unsigned long start_pfn, end_pfn; int i, nid; /* 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)); arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions(); arch_zone_highest_possible_pfn[0] = max_zone_pfn[0]; for (i = 1; i < MAX_NR_ZONES; i++) { if (i == ZONE_MOVABLE) continue; arch_zone_lowest_possible_pfn[i] = arch_zone_highest_possible_pfn[i-1]; arch_zone_highest_possible_pfn[i] = max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]); } arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0; arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0; /* 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 */ 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); /* 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, NULL, find_min_pfn_for_node(nid), NULL); /* 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 long coremem; if (!p) return -EINVAL; coremem = memparse(p, &p); *core = coremem >> PAGE_SHIFT; /* Paranoid check that UL is enough for the coremem value */ WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX); 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) { return cmdline_parse_core(p, &required_kernelcore); } /* * 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); } early_param("kernelcore", cmdline_parse_kernelcore); early_param("movablecore", cmdline_parse_movablecore); #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ void adjust_managed_page_count(struct page *page, long count) { spin_lock(&managed_page_count_lock); page_zone(page)->managed_pages += count; totalram_pages += count; #ifdef CONFIG_HIGHMEM if (PageHighMem(page)) totalhigh_pages += count; #endif spin_unlock(&managed_page_count_lock); } EXPORT_SYMBOL(adjust_managed_page_count); unsigned long free_reserved_area(void *start, void *end, int poison, 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++) { if ((unsigned int)poison <= 0xFF) memset(pos, poison, PAGE_SIZE); free_reserved_page(virt_to_page(pos)); } if (pages && s) pr_info("Freeing %s memory: %ldK (%p - %p)\n", s, pages << (PAGE_SHIFT - 10), start, end); return pages; } EXPORT_SYMBOL(free_reserved_area); #ifdef CONFIG_HIGHMEM void free_highmem_page(struct page *page) { __free_reserved_page(page); totalram_pages++; page_zone(page)->managed_pages++; totalhigh_pages++; } #endif void __init mem_init_print_info(const char *str) { 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 "%s%s)\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 str ? ", " : "", str ? str : ""); } /** * 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; } void __init free_area_init(unsigned long *zones_size) { free_area_init_node(0, zones_size, __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL); } static int page_alloc_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { int cpu = (unsigned long)hcpu; if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) { 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 NOTIFY_OK; } void __init page_alloc_init(void) { hotcpu_notifier(page_alloc_cpu_notify, 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) { for (i = 0; i < MAX_NR_ZONES; i++) { struct zone *zone = pgdat->node_zones + i; long max = 0; /* 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 > zone->managed_pages) max = zone->managed_pages; zone->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 j, idx; for_each_online_pgdat(pgdat) { for (j = 0; j < MAX_NR_ZONES; j++) { struct zone *zone = pgdat->node_zones + j; unsigned long managed_pages = zone->managed_pages; zone->lowmem_reserve[j] = 0; idx = j; while (idx) { struct zone *lower_zone; idx--; if (sysctl_lowmem_reserve_ratio[idx] < 1) sysctl_lowmem_reserve_ratio[idx] = 1; lower_zone = pgdat->node_zones + idx; lower_zone->lowmem_reserve[j] = managed_pages / sysctl_lowmem_reserve_ratio[idx]; managed_pages += lower_zone->managed_pages; } } } /* 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; } for_each_zone(zone) { u64 tmp; spin_lock_irqsave(&zone->lock, flags); tmp = (u64)pages_min * zone->managed_pages; 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 asynch page reclaim, and so should * not be capped for highmem. */ unsigned long min_pages; min_pages = zone->managed_pages / 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; } zone->watermark[WMARK_LOW] = min_wmark_pages(zone) + (tmp >> 2); zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1); __mod_zone_page_state(zone, NR_ALLOC_BATCH, high_wmark_pages(zone) - low_wmark_pages(zone) - atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH])); 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) { mutex_lock(&zonelists_mutex); __setup_per_zone_wmarks(); mutex_unlock(&zonelists_mutex); } /* * The inactive anon list should be small enough that the VM never has to * do too much work, but large enough that each inactive page has a chance * to be referenced again before it is swapped out. * * The inactive_anon ratio is the target ratio of ACTIVE_ANON to * INACTIVE_ANON pages on this zone's LRU, maintained by the * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of * the anonymous pages are kept on the inactive list. * * total target max * memory ratio inactive anon * ------------------------------------- * 10MB 1 5MB * 100MB 1 50MB * 1GB 3 250MB * 10GB 10 0.9GB * 100GB 31 3GB * 1TB 101 10GB * 10TB 320 32GB */ static void __meminit calculate_zone_inactive_ratio(struct zone *zone) { unsigned int gb, ratio; /* Zone size in gigabytes */ gb = zone->managed_pages >> (30 - PAGE_SHIFT); if (gb) ratio = int_sqrt(10 * gb); else ratio = 1; zone->inactive_ratio = ratio; } static void __meminit setup_per_zone_inactive_ratio(void) { struct zone *zone; for_each_zone(zone) calculate_zone_inactive_ratio(zone); } /* * Initialise min_free_kbytes. * * For small machines we want it small (128k min). For large machines * we want it large (64MB 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 > 65536) min_free_kbytes = 65536; } 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(); setup_per_zone_inactive_ratio(); return 0; } module_init(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 __user *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; } #ifdef CONFIG_NUMA int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { struct zone *zone; int rc; rc = proc_dointvec_minmax(table, write, buffer, length, ppos); if (rc) return rc; for_each_zone(zone) zone->min_unmapped_pages = (zone->managed_pages * sysctl_min_unmapped_ratio) / 100; return 0; } int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { struct zone *zone; int rc; rc = proc_dointvec_minmax(table, write, buffer, length, ppos); if (rc) return rc; for_each_zone(zone) zone->min_slab_pages = (zone->managed_pages * sysctl_min_slab_ratio) / 100; 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 __user *buffer, size_t *length, loff_t *ppos) { proc_dointvec_minmax(table, write, buffer, length, ppos); 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 __user *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) { unsigned int cpu; for_each_possible_cpu(cpu) pageset_set_high_and_batch(zone, per_cpu_ptr(zone->pageset, cpu)); } out: mutex_unlock(&pcp_batch_high_lock); return ret; } #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 /* * 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; /* allow the kernel cmdline to have a say */ if (!numentries) { /* round applicable memory size up to nearest megabyte */ numentries = nr_kernel_pages; /* It isn't necessary when PAGE_SIZE >= 1MB */ if (PAGE_SHIFT < 20) numentries = round_up(numentries, (1<<20)/PAGE_SIZE); /* 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); do { size = bucketsize << log2qty; if (flags & HASH_EARLY) table = memblock_virt_alloc_nopanic(size, 0); else if (hashdist) table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL); 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 */ if (get_order(size) < MAX_ORDER) { table = alloc_pages_exact(size, GFP_ATOMIC); kmemleak_alloc(table, size, 1, GFP_ATOMIC); } } } while (!table && size > PAGE_SIZE && --log2qty); if (!table) panic("Failed to allocate %s hash table\n", tablename); printk(KERN_INFO "%s hash table entries: %ld (order: %d, %lu bytes)\n", tablename, (1UL << log2qty), ilog2(size) - PAGE_SHIFT, size); if (_hash_shift) *_hash_shift = log2qty; if (_hash_mask) *_hash_mask = (1 << log2qty) - 1; return table; } /* Return a pointer to the bitmap storing bits affecting a block of pages */ static inline unsigned long *get_pageblock_bitmap(struct zone *zone, unsigned long pfn) { #ifdef CONFIG_SPARSEMEM return __pfn_to_section(pfn)->pageblock_flags; #else return zone->pageblock_flags; #endif /* CONFIG_SPARSEMEM */ } static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn) { #ifdef CONFIG_SPARSEMEM pfn &= (PAGES_PER_SECTION-1); return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS; #else pfn = pfn - round_down(zone->zone_start_pfn, pageblock_nr_pages); return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS; #endif /* CONFIG_SPARSEMEM */ } /** * 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 * @end_bitidx: The last bit of interest to retrieve * @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 end_bitidx, unsigned long mask) { struct zone *zone; unsigned long *bitmap; unsigned long bitidx, word_bitidx; unsigned long word; zone = page_zone(page); bitmap = get_pageblock_bitmap(zone, pfn); bitidx = pfn_to_bitidx(zone, pfn); word_bitidx = bitidx / BITS_PER_LONG; bitidx &= (BITS_PER_LONG-1); word = bitmap[word_bitidx]; bitidx += end_bitidx; return (word >> (BITS_PER_LONG - bitidx - 1)) & 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 * @end_bitidx: The last bit of interest * @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 end_bitidx, unsigned long mask) { struct zone *zone; unsigned long *bitmap; unsigned long bitidx, word_bitidx; unsigned long old_word, word; BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4); zone = page_zone(page); bitmap = get_pageblock_bitmap(zone, pfn); bitidx = pfn_to_bitidx(zone, pfn); word_bitidx = bitidx / BITS_PER_LONG; bitidx &= (BITS_PER_LONG-1); VM_BUG_ON_PAGE(!zone_spans_pfn(zone, pfn), page); bitidx += end_bitidx; mask <<= (BITS_PER_LONG - bitidx - 1); flags <<= (BITS_PER_LONG - bitidx - 1); 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; } } /* * This function checks whether pageblock includes unmovable pages or not. * If @count is not zero, it is okay to include less @count unmovable pages * * PageLRU check without isolation or lru_lock could race so that * MIGRATE_MOVABLE block might include unmovable pages. It means you can't * expect this function should be exact. */ bool has_unmovable_pages(struct zone *zone, struct page *page, int count, bool skip_hwpoisoned_pages) { unsigned long pfn, iter, found; int mt; /* * For avoiding noise data, lru_add_drain_all() should be called * If ZONE_MOVABLE, the zone never contains unmovable pages */ if (zone_idx(zone) == ZONE_MOVABLE) return false; mt = get_pageblock_migratetype(page); if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt)) return false; pfn = page_to_pfn(page); for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) { unsigned long check = pfn + iter; if (!pfn_valid_within(check)) continue; page = pfn_to_page(check); /* * Hugepages are not in LRU lists, but they're movable. * We need not scan over tail pages bacause we don't * handle each tail page individually in migration. */ if (PageHuge(page)) { iter = round_up(iter + 1, 1<_count is zero at all time. */ if (!atomic_read(&page->_count)) { if (PageBuddy(page)) iter += (1 << page_order(page)) - 1; continue; } /* * The HWPoisoned page may be not in buddy system, and * page_count() is not 0. */ if (skip_hwpoisoned_pages && PageHWPoison(page)) continue; if (!PageLRU(page)) found++; /* * 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. */ /* * If the page is not RAM, page_count()should be 0. * we don't need more check. This is an _used_ not-movable page. * * The problematic thing here is PG_reserved pages. PG_reserved * is set to both of a memory hole page and a _used_ kernel * page at boot. */ if (found > count) return true; } return false; } bool is_pageblock_removable_nolock(struct page *page) { struct zone *zone; unsigned long pfn; /* * We have to be careful here because we are iterating over memory * sections which are not zone aware so we might end up outside of * the zone but still within the section. * We have to take care about the node as well. If the node is offline * its NODE_DATA will be NULL - see page_zone. */ if (!node_online(page_to_nid(page))) return false; zone = page_zone(page); pfn = page_to_pfn(page); if (!zone_spans_pfn(zone, pfn)) return false; return !has_unmovable_pages(zone, page, 0, true); } #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA) 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)); } /* [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 long nr_reclaimed; unsigned long pfn = start; unsigned int tries = 0; int ret = 0; migrate_prep(); while (pfn < end || !list_empty(&cc->migratepages)) { if (fatal_signal_pending(current)) { ret = -EINTR; break; } if (list_empty(&cc->migratepages)) { cc->nr_migratepages = 0; pfn = isolate_migratepages_range(cc, pfn, end); if (!pfn) { ret = -EINTR; break; } tries = 0; } else if (++tries == 5) { ret = ret < 0 ? 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_migrate_target, NULL, 0, cc->mode, MR_CMA); } if (ret < 0) { 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 underlaying pageblocks (either * #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks * in range must have the same migratetype and it must * be either of the two. * * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES * aligned, however it's the caller's responsibility to guarantee that * we are the only thread that changes migrate type of pageblocks the * pages fall in. * * The PFN range must belong to a single zone. * * Returns 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) { 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, }; 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, false); if (ret) return ret; /* * In case of -EBUSY, we'd like to know which page causes problem. * So, just fall through. We will check it in test_pages_isolated(). */ ret = __alloc_contig_migrate_range(&cc, start, end); if (ret && ret != -EBUSY) goto done; /* * 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. */ lru_add_drain_all(); drain_all_pages(cc.zone); 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 = page_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, false)) { pr_info("%s: [%lx, %lx) PFNs busy\n", __func__, outer_start, end); 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; } void free_contig_range(unsigned long pfn, unsigned nr_pages) { unsigned int count = 0; for (; nr_pages--; pfn++) { struct page *page = pfn_to_page(pfn); count += page_count(page) != 1; __free_page(page); } WARN(count != 0, "%d pages are still in use!\n", count); } #endif #ifdef CONFIG_MEMORY_HOTPLUG /* * The zone indicated has a new number of managed_pages; batch sizes and percpu * page high values need to be recalulated. */ void __meminit zone_pcp_update(struct zone *zone) { unsigned cpu; mutex_lock(&pcp_batch_high_lock); for_each_possible_cpu(cpu) pageset_set_high_and_batch(zone, per_cpu_ptr(zone->pageset, cpu)); mutex_unlock(&pcp_batch_high_lock); } #endif void zone_pcp_reset(struct zone *zone) { unsigned long flags; int cpu; struct per_cpu_pageset *pset; /* avoid races with drain_pages() */ local_irq_save(flags); 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; } local_irq_restore(flags); } #ifdef CONFIG_MEMORY_HOTREMOVE /* * All pages in the range must be isolated before calling this. */ void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) { struct page *page; struct zone *zone; unsigned int order, i; unsigned long pfn; unsigned long flags; /* find the first valid pfn */ for (pfn = start_pfn; pfn < end_pfn; pfn++) if (pfn_valid(pfn)) break; if (pfn == end_pfn) return; zone = page_zone(pfn_to_page(pfn)); spin_lock_irqsave(&zone->lock, flags); pfn = start_pfn; while (pfn < end_pfn) { if (!pfn_valid(pfn)) { pfn++; continue; } 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++; SetPageReserved(page); continue; } BUG_ON(page_count(page)); BUG_ON(!PageBuddy(page)); order = page_order(page); #ifdef CONFIG_DEBUG_VM printk(KERN_INFO "remove from free list %lx %d %lx\n", pfn, 1 << order, end_pfn); #endif list_del(&page->lru); rmv_page_order(page); zone->free_area[order].nr_free--; for (i = 0; i < (1 << order); i++) SetPageReserved((page+i)); pfn += (1 << order); } spin_unlock_irqrestore(&zone->lock, flags); } #endif #ifdef CONFIG_MEMORY_FAILURE 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) && page_order(page_head) >= order) break; } spin_unlock_irqrestore(&zone->lock, flags); return order < MAX_ORDER; } #endif