2 * linux/mm/page_alloc.c
4 * Manages the free list, the system allocates free pages here.
5 * Note that kmalloc() lives in slab.c
7 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
8 * Swap reorganised 29.12.95, Stephen Tweedie
9 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
10 * Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
11 * Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
12 * Zone balancing, Kanoj Sarcar, SGI, Jan 2000
13 * Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
14 * (lots of bits borrowed from Ingo Molnar & Andrew Morton)
17 #include <linux/stddef.h>
19 #include <linux/swap.h>
20 #include <linux/interrupt.h>
21 #include <linux/pagemap.h>
22 #include <linux/jiffies.h>
23 #include <linux/bootmem.h>
24 #include <linux/memblock.h>
25 #include <linux/compiler.h>
26 #include <linux/kernel.h>
27 #include <linux/kmemcheck.h>
28 #include <linux/module.h>
29 #include <linux/suspend.h>
30 #include <linux/pagevec.h>
31 #include <linux/blkdev.h>
32 #include <linux/slab.h>
33 #include <linux/ratelimit.h>
34 #include <linux/oom.h>
35 #include <linux/notifier.h>
36 #include <linux/topology.h>
37 #include <linux/sysctl.h>
38 #include <linux/cpu.h>
39 #include <linux/cpuset.h>
40 #include <linux/memory_hotplug.h>
41 #include <linux/nodemask.h>
42 #include <linux/vmalloc.h>
43 #include <linux/vmstat.h>
44 #include <linux/mempolicy.h>
45 #include <linux/stop_machine.h>
46 #include <linux/sort.h>
47 #include <linux/pfn.h>
48 #include <linux/backing-dev.h>
49 #include <linux/fault-inject.h>
50 #include <linux/page-isolation.h>
51 #include <linux/page_cgroup.h>
52 #include <linux/debugobjects.h>
53 #include <linux/kmemleak.h>
54 #include <linux/memory.h>
55 #include <linux/compaction.h>
56 #include <trace/events/kmem.h>
57 #include <linux/ftrace_event.h>
58 #include <linux/memcontrol.h>
59 #include <linux/prefetch.h>
60 #include <linux/migrate.h>
61 #include <linux/page-debug-flags.h>
63 #include <asm/tlbflush.h>
64 #include <asm/div64.h>
67 #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
68 DEFINE_PER_CPU(int, numa_node);
69 EXPORT_PER_CPU_SYMBOL(numa_node);
72 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
74 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
75 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
76 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
77 * defined in <linux/topology.h>.
79 DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */
80 EXPORT_PER_CPU_SYMBOL(_numa_mem_);
84 * Array of node states.
86 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
87 [N_POSSIBLE] = NODE_MASK_ALL,
88 [N_ONLINE] = { { [0] = 1UL } },
90 [N_NORMAL_MEMORY] = { { [0] = 1UL } },
92 [N_HIGH_MEMORY] = { { [0] = 1UL } },
94 [N_CPU] = { { [0] = 1UL } },
97 EXPORT_SYMBOL(node_states);
99 unsigned long totalram_pages __read_mostly;
100 unsigned long totalreserve_pages __read_mostly;
102 * When calculating the number of globally allowed dirty pages, there
103 * is a certain number of per-zone reserves that should not be
104 * considered dirtyable memory. This is the sum of those reserves
105 * over all existing zones that contribute dirtyable memory.
107 unsigned long dirty_balance_reserve __read_mostly;
109 int percpu_pagelist_fraction;
110 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
112 #ifdef CONFIG_PM_SLEEP
114 * The following functions are used by the suspend/hibernate code to temporarily
115 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
116 * while devices are suspended. To avoid races with the suspend/hibernate code,
117 * they should always be called with pm_mutex held (gfp_allowed_mask also should
118 * only be modified with pm_mutex held, unless the suspend/hibernate code is
119 * guaranteed not to run in parallel with that modification).
122 static gfp_t saved_gfp_mask;
124 void pm_restore_gfp_mask(void)
126 WARN_ON(!mutex_is_locked(&pm_mutex));
127 if (saved_gfp_mask) {
128 gfp_allowed_mask = saved_gfp_mask;
133 void pm_restrict_gfp_mask(void)
135 WARN_ON(!mutex_is_locked(&pm_mutex));
136 WARN_ON(saved_gfp_mask);
137 saved_gfp_mask = gfp_allowed_mask;
138 gfp_allowed_mask &= ~GFP_IOFS;
141 bool pm_suspended_storage(void)
143 if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS)
147 #endif /* CONFIG_PM_SLEEP */
149 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
150 int pageblock_order __read_mostly;
153 static void __free_pages_ok(struct page *page, unsigned int order);
156 * results with 256, 32 in the lowmem_reserve sysctl:
157 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
158 * 1G machine -> (16M dma, 784M normal, 224M high)
159 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
160 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
161 * HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
163 * TBD: should special case ZONE_DMA32 machines here - in those we normally
164 * don't need any ZONE_NORMAL reservation
166 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
167 #ifdef CONFIG_ZONE_DMA
170 #ifdef CONFIG_ZONE_DMA32
173 #ifdef CONFIG_HIGHMEM
179 EXPORT_SYMBOL(totalram_pages);
181 static char * const zone_names[MAX_NR_ZONES] = {
182 #ifdef CONFIG_ZONE_DMA
185 #ifdef CONFIG_ZONE_DMA32
189 #ifdef CONFIG_HIGHMEM
195 int min_free_kbytes = 1024;
197 static unsigned long __meminitdata nr_kernel_pages;
198 static unsigned long __meminitdata nr_all_pages;
199 static unsigned long __meminitdata dma_reserve;
201 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
202 static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
203 static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
204 static unsigned long __initdata required_kernelcore;
205 static unsigned long __initdata required_movablecore;
206 static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
208 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
210 EXPORT_SYMBOL(movable_zone);
211 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
214 int nr_node_ids __read_mostly = MAX_NUMNODES;
215 int nr_online_nodes __read_mostly = 1;
216 EXPORT_SYMBOL(nr_node_ids);
217 EXPORT_SYMBOL(nr_online_nodes);
220 int page_group_by_mobility_disabled __read_mostly;
222 static void set_pageblock_migratetype(struct page *page, int migratetype)
225 if (unlikely(page_group_by_mobility_disabled))
226 migratetype = MIGRATE_UNMOVABLE;
228 set_pageblock_flags_group(page, (unsigned long)migratetype,
229 PB_migrate, PB_migrate_end);
232 bool oom_killer_disabled __read_mostly;
234 #ifdef CONFIG_DEBUG_VM
235 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
239 unsigned long pfn = page_to_pfn(page);
242 seq = zone_span_seqbegin(zone);
243 if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
245 else if (pfn < zone->zone_start_pfn)
247 } while (zone_span_seqretry(zone, seq));
252 static int page_is_consistent(struct zone *zone, struct page *page)
254 if (!pfn_valid_within(page_to_pfn(page)))
256 if (zone != page_zone(page))
262 * Temporary debugging check for pages not lying within a given zone.
264 static int bad_range(struct zone *zone, struct page *page)
266 if (page_outside_zone_boundaries(zone, page))
268 if (!page_is_consistent(zone, page))
274 static inline int bad_range(struct zone *zone, struct page *page)
280 static void bad_page(struct page *page)
282 static unsigned long resume;
283 static unsigned long nr_shown;
284 static unsigned long nr_unshown;
286 /* Don't complain about poisoned pages */
287 if (PageHWPoison(page)) {
288 reset_page_mapcount(page); /* remove PageBuddy */
293 * Allow a burst of 60 reports, then keep quiet for that minute;
294 * or allow a steady drip of one report per second.
296 if (nr_shown == 60) {
297 if (time_before(jiffies, resume)) {
303 "BUG: Bad page state: %lu messages suppressed\n",
310 resume = jiffies + 60 * HZ;
312 printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n",
313 current->comm, page_to_pfn(page));
319 /* Leave bad fields for debug, except PageBuddy could make trouble */
320 reset_page_mapcount(page); /* remove PageBuddy */
321 add_taint(TAINT_BAD_PAGE);
325 * Higher-order pages are called "compound pages". They are structured thusly:
327 * The first PAGE_SIZE page is called the "head page".
329 * The remaining PAGE_SIZE pages are called "tail pages".
331 * All pages have PG_compound set. All tail pages have their ->first_page
332 * pointing at the head page.
334 * The first tail page's ->lru.next holds the address of the compound page's
335 * put_page() function. Its ->lru.prev holds the order of allocation.
336 * This usage means that zero-order pages may not be compound.
339 static void free_compound_page(struct page *page)
341 __free_pages_ok(page, compound_order(page));
344 void prep_compound_page(struct page *page, unsigned long order)
347 int nr_pages = 1 << order;
349 set_compound_page_dtor(page, free_compound_page);
350 set_compound_order(page, order);
352 for (i = 1; i < nr_pages; i++) {
353 struct page *p = page + i;
355 set_page_count(p, 0);
356 p->first_page = page;
360 /* update __split_huge_page_refcount if you change this function */
361 static int destroy_compound_page(struct page *page, unsigned long order)
364 int nr_pages = 1 << order;
367 if (unlikely(compound_order(page) != order) ||
368 unlikely(!PageHead(page))) {
373 __ClearPageHead(page);
375 for (i = 1; i < nr_pages; i++) {
376 struct page *p = page + i;
378 if (unlikely(!PageTail(p) || (p->first_page != page))) {
388 static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
393 * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
394 * and __GFP_HIGHMEM from hard or soft interrupt context.
396 VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
397 for (i = 0; i < (1 << order); i++)
398 clear_highpage(page + i);
401 #ifdef CONFIG_DEBUG_PAGEALLOC
402 unsigned int _debug_guardpage_minorder;
404 static int __init debug_guardpage_minorder_setup(char *buf)
408 if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) {
409 printk(KERN_ERR "Bad debug_guardpage_minorder value\n");
412 _debug_guardpage_minorder = res;
413 printk(KERN_INFO "Setting debug_guardpage_minorder to %lu\n", res);
416 __setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup);
418 static inline void set_page_guard_flag(struct page *page)
420 __set_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
423 static inline void clear_page_guard_flag(struct page *page)
425 __clear_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
428 static inline void set_page_guard_flag(struct page *page) { }
429 static inline void clear_page_guard_flag(struct page *page) { }
432 static inline void set_page_order(struct page *page, int order)
434 set_page_private(page, order);
435 __SetPageBuddy(page);
438 static inline void rmv_page_order(struct page *page)
440 __ClearPageBuddy(page);
441 set_page_private(page, 0);
445 * Locate the struct page for both the matching buddy in our
446 * pair (buddy1) and the combined O(n+1) page they form (page).
448 * 1) Any buddy B1 will have an order O twin B2 which satisfies
449 * the following equation:
451 * For example, if the starting buddy (buddy2) is #8 its order
453 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
455 * 2) Any buddy B will have an order O+1 parent P which
456 * satisfies the following equation:
459 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
461 static inline unsigned long
462 __find_buddy_index(unsigned long page_idx, unsigned int order)
464 return page_idx ^ (1 << order);
468 * This function checks whether a page is free && is the buddy
469 * we can do coalesce a page and its buddy if
470 * (a) the buddy is not in a hole &&
471 * (b) the buddy is in the buddy system &&
472 * (c) a page and its buddy have the same order &&
473 * (d) a page and its buddy are in the same zone.
475 * For recording whether a page is in the buddy system, we set ->_mapcount -2.
476 * Setting, clearing, and testing _mapcount -2 is serialized by zone->lock.
478 * For recording page's order, we use page_private(page).
480 static inline int page_is_buddy(struct page *page, struct page *buddy,
483 if (!pfn_valid_within(page_to_pfn(buddy)))
486 if (page_zone_id(page) != page_zone_id(buddy))
489 if (page_is_guard(buddy) && page_order(buddy) == order) {
490 VM_BUG_ON(page_count(buddy) != 0);
494 if (PageBuddy(buddy) && page_order(buddy) == order) {
495 VM_BUG_ON(page_count(buddy) != 0);
502 * Freeing function for a buddy system allocator.
504 * The concept of a buddy system is to maintain direct-mapped table
505 * (containing bit values) for memory blocks of various "orders".
506 * The bottom level table contains the map for the smallest allocatable
507 * units of memory (here, pages), and each level above it describes
508 * pairs of units from the levels below, hence, "buddies".
509 * At a high level, all that happens here is marking the table entry
510 * at the bottom level available, and propagating the changes upward
511 * as necessary, plus some accounting needed to play nicely with other
512 * parts of the VM system.
513 * At each level, we keep a list of pages, which are heads of continuous
514 * free pages of length of (1 << order) and marked with _mapcount -2. Page's
515 * order is recorded in page_private(page) field.
516 * So when we are allocating or freeing one, we can derive the state of the
517 * other. That is, if we allocate a small block, and both were
518 * free, the remainder of the region must be split into blocks.
519 * If a block is freed, and its buddy is also free, then this
520 * triggers coalescing into a block of larger size.
525 static inline void __free_one_page(struct page *page,
526 struct zone *zone, unsigned int order,
529 unsigned long page_idx;
530 unsigned long combined_idx;
531 unsigned long uninitialized_var(buddy_idx);
534 if (unlikely(PageCompound(page)))
535 if (unlikely(destroy_compound_page(page, order)))
538 VM_BUG_ON(migratetype == -1);
540 page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
542 VM_BUG_ON(page_idx & ((1 << order) - 1));
543 VM_BUG_ON(bad_range(zone, page));
545 while (order < MAX_ORDER-1) {
546 buddy_idx = __find_buddy_index(page_idx, order);
547 buddy = page + (buddy_idx - page_idx);
548 if (!page_is_buddy(page, buddy, order))
551 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
552 * merge with it and move up one order.
554 if (page_is_guard(buddy)) {
555 clear_page_guard_flag(buddy);
556 set_page_private(page, 0);
557 __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
559 list_del(&buddy->lru);
560 zone->free_area[order].nr_free--;
561 rmv_page_order(buddy);
563 combined_idx = buddy_idx & page_idx;
564 page = page + (combined_idx - page_idx);
565 page_idx = combined_idx;
568 set_page_order(page, order);
571 * If this is not the largest possible page, check if the buddy
572 * of the next-highest order is free. If it is, it's possible
573 * that pages are being freed that will coalesce soon. In case,
574 * that is happening, add the free page to the tail of the list
575 * so it's less likely to be used soon and more likely to be merged
576 * as a higher order page
578 if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
579 struct page *higher_page, *higher_buddy;
580 combined_idx = buddy_idx & page_idx;
581 higher_page = page + (combined_idx - page_idx);
582 buddy_idx = __find_buddy_index(combined_idx, order + 1);
583 higher_buddy = page + (buddy_idx - combined_idx);
584 if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
585 list_add_tail(&page->lru,
586 &zone->free_area[order].free_list[migratetype]);
591 list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
593 zone->free_area[order].nr_free++;
597 * free_page_mlock() -- clean up attempts to free and mlocked() page.
598 * Page should not be on lru, so no need to fix that up.
599 * free_pages_check() will verify...
601 static inline void free_page_mlock(struct page *page)
603 __dec_zone_page_state(page, NR_MLOCK);
604 __count_vm_event(UNEVICTABLE_MLOCKFREED);
607 static inline int free_pages_check(struct page *page)
609 if (unlikely(page_mapcount(page) |
610 (page->mapping != NULL) |
611 (atomic_read(&page->_count) != 0) |
612 (page->flags & PAGE_FLAGS_CHECK_AT_FREE) |
613 (mem_cgroup_bad_page_check(page)))) {
617 if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
618 page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
623 * Frees a number of pages from the PCP lists
624 * Assumes all pages on list are in same zone, and of same order.
625 * count is the number of pages to free.
627 * If the zone was previously in an "all pages pinned" state then look to
628 * see if this freeing clears that state.
630 * And clear the zone's pages_scanned counter, to hold off the "all pages are
631 * pinned" detection logic.
633 static void free_pcppages_bulk(struct zone *zone, int count,
634 struct per_cpu_pages *pcp)
640 spin_lock(&zone->lock);
641 zone->all_unreclaimable = 0;
642 zone->pages_scanned = 0;
646 struct list_head *list;
649 * Remove pages from lists in a round-robin fashion. A
650 * batch_free count is maintained that is incremented when an
651 * empty list is encountered. This is so more pages are freed
652 * off fuller lists instead of spinning excessively around empty
657 if (++migratetype == MIGRATE_PCPTYPES)
659 list = &pcp->lists[migratetype];
660 } while (list_empty(list));
662 /* This is the only non-empty list. Free them all. */
663 if (batch_free == MIGRATE_PCPTYPES)
664 batch_free = to_free;
667 page = list_entry(list->prev, struct page, lru);
668 /* must delete as __free_one_page list manipulates */
669 list_del(&page->lru);
670 /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
671 __free_one_page(page, zone, 0, page_private(page));
672 trace_mm_page_pcpu_drain(page, 0, page_private(page));
673 } while (--to_free && --batch_free && !list_empty(list));
675 __mod_zone_page_state(zone, NR_FREE_PAGES, count);
676 spin_unlock(&zone->lock);
679 static void free_one_page(struct zone *zone, struct page *page, int order,
682 spin_lock(&zone->lock);
683 zone->all_unreclaimable = 0;
684 zone->pages_scanned = 0;
686 __free_one_page(page, zone, order, migratetype);
687 __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
688 spin_unlock(&zone->lock);
691 static bool free_pages_prepare(struct page *page, unsigned int order)
696 trace_mm_page_free(page, order);
697 kmemcheck_free_shadow(page, order);
700 page->mapping = NULL;
701 for (i = 0; i < (1 << order); i++)
702 bad += free_pages_check(page + i);
706 if (!PageHighMem(page)) {
707 debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
708 debug_check_no_obj_freed(page_address(page),
711 arch_free_page(page, order);
712 kernel_map_pages(page, 1 << order, 0);
717 static void __free_pages_ok(struct page *page, unsigned int order)
720 int wasMlocked = __TestClearPageMlocked(page);
722 if (!free_pages_prepare(page, order))
725 local_irq_save(flags);
726 if (unlikely(wasMlocked))
727 free_page_mlock(page);
728 __count_vm_events(PGFREE, 1 << order);
729 free_one_page(page_zone(page), page, order,
730 get_pageblock_migratetype(page));
731 local_irq_restore(flags);
734 void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
736 unsigned int nr_pages = 1 << order;
740 for (loop = 0; loop < nr_pages; loop++) {
741 struct page *p = &page[loop];
743 if (loop + 1 < nr_pages)
745 __ClearPageReserved(p);
746 set_page_count(p, 0);
749 set_page_refcounted(page);
750 __free_pages(page, order);
755 * The order of subdivision here is critical for the IO subsystem.
756 * Please do not alter this order without good reasons and regression
757 * testing. Specifically, as large blocks of memory are subdivided,
758 * the order in which smaller blocks are delivered depends on the order
759 * they're subdivided in this function. This is the primary factor
760 * influencing the order in which pages are delivered to the IO
761 * subsystem according to empirical testing, and this is also justified
762 * by considering the behavior of a buddy system containing a single
763 * large block of memory acted on by a series of small allocations.
764 * This behavior is a critical factor in sglist merging's success.
768 static inline void expand(struct zone *zone, struct page *page,
769 int low, int high, struct free_area *area,
772 unsigned long size = 1 << high;
778 VM_BUG_ON(bad_range(zone, &page[size]));
780 #ifdef CONFIG_DEBUG_PAGEALLOC
781 if (high < debug_guardpage_minorder()) {
783 * Mark as guard pages (or page), that will allow to
784 * merge back to allocator when buddy will be freed.
785 * Corresponding page table entries will not be touched,
786 * pages will stay not present in virtual address space
788 INIT_LIST_HEAD(&page[size].lru);
789 set_page_guard_flag(&page[size]);
790 set_page_private(&page[size], high);
791 /* Guard pages are not available for any usage */
792 __mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << high));
796 list_add(&page[size].lru, &area->free_list[migratetype]);
798 set_page_order(&page[size], high);
803 * This page is about to be returned from the page allocator
805 static inline int check_new_page(struct page *page)
807 if (unlikely(page_mapcount(page) |
808 (page->mapping != NULL) |
809 (atomic_read(&page->_count) != 0) |
810 (page->flags & PAGE_FLAGS_CHECK_AT_PREP) |
811 (mem_cgroup_bad_page_check(page)))) {
818 static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
822 for (i = 0; i < (1 << order); i++) {
823 struct page *p = page + i;
824 if (unlikely(check_new_page(p)))
828 set_page_private(page, 0);
829 set_page_refcounted(page);
831 arch_alloc_page(page, order);
832 kernel_map_pages(page, 1 << order, 1);
834 if (gfp_flags & __GFP_ZERO)
835 prep_zero_page(page, order, gfp_flags);
837 if (order && (gfp_flags & __GFP_COMP))
838 prep_compound_page(page, order);
844 * Go through the free lists for the given migratetype and remove
845 * the smallest available page from the freelists
848 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
851 unsigned int current_order;
852 struct free_area * area;
855 /* Find a page of the appropriate size in the preferred list */
856 for (current_order = order; current_order < MAX_ORDER; ++current_order) {
857 area = &(zone->free_area[current_order]);
858 if (list_empty(&area->free_list[migratetype]))
861 page = list_entry(area->free_list[migratetype].next,
863 list_del(&page->lru);
864 rmv_page_order(page);
866 expand(zone, page, order, current_order, area, migratetype);
875 * This array describes the order lists are fallen back to when
876 * the free lists for the desirable migrate type are depleted
878 static int fallbacks[MIGRATE_TYPES][3] = {
879 [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
880 [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
881 [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
882 [MIGRATE_RESERVE] = { MIGRATE_RESERVE }, /* Never used */
883 [MIGRATE_ISOLATE] = { MIGRATE_RESERVE }, /* Never used */
887 * Move the free pages in a range to the free lists of the requested type.
888 * Note that start_page and end_pages are not aligned on a pageblock
889 * boundary. If alignment is required, use move_freepages_block()
891 static int move_freepages(struct zone *zone,
892 struct page *start_page, struct page *end_page,
899 #ifndef CONFIG_HOLES_IN_ZONE
901 * page_zone is not safe to call in this context when
902 * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
903 * anyway as we check zone boundaries in move_freepages_block().
904 * Remove at a later date when no bug reports exist related to
905 * grouping pages by mobility
907 BUG_ON(page_zone(start_page) != page_zone(end_page));
910 for (page = start_page; page <= end_page;) {
911 /* Make sure we are not inadvertently changing nodes */
912 VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
914 if (!pfn_valid_within(page_to_pfn(page))) {
919 if (!PageBuddy(page)) {
924 order = page_order(page);
925 list_move(&page->lru,
926 &zone->free_area[order].free_list[migratetype]);
928 pages_moved += 1 << order;
934 static int move_freepages_block(struct zone *zone, struct page *page,
937 unsigned long start_pfn, end_pfn;
938 struct page *start_page, *end_page;
940 start_pfn = page_to_pfn(page);
941 start_pfn = start_pfn & ~(pageblock_nr_pages-1);
942 start_page = pfn_to_page(start_pfn);
943 end_page = start_page + pageblock_nr_pages - 1;
944 end_pfn = start_pfn + pageblock_nr_pages - 1;
946 /* Do not cross zone boundaries */
947 if (start_pfn < zone->zone_start_pfn)
949 if (end_pfn >= zone->zone_start_pfn + zone->spanned_pages)
952 return move_freepages(zone, start_page, end_page, migratetype);
955 static void change_pageblock_range(struct page *pageblock_page,
956 int start_order, int migratetype)
958 int nr_pageblocks = 1 << (start_order - pageblock_order);
960 while (nr_pageblocks--) {
961 set_pageblock_migratetype(pageblock_page, migratetype);
962 pageblock_page += pageblock_nr_pages;
966 /* Remove an element from the buddy allocator from the fallback list */
967 static inline struct page *
968 __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
970 struct free_area * area;
975 /* Find the largest possible block of pages in the other list */
976 for (current_order = MAX_ORDER-1; current_order >= order;
979 migratetype = fallbacks[start_migratetype][i];
981 /* MIGRATE_RESERVE handled later if necessary */
982 if (migratetype == MIGRATE_RESERVE)
985 area = &(zone->free_area[current_order]);
986 if (list_empty(&area->free_list[migratetype]))
989 page = list_entry(area->free_list[migratetype].next,
994 * If breaking a large block of pages, move all free
995 * pages to the preferred allocation list. If falling
996 * back for a reclaimable kernel allocation, be more
997 * aggressive about taking ownership of free pages
999 if (unlikely(current_order >= (pageblock_order >> 1)) ||
1000 start_migratetype == MIGRATE_RECLAIMABLE ||
1001 page_group_by_mobility_disabled) {
1002 unsigned long pages;
1003 pages = move_freepages_block(zone, page,
1006 /* Claim the whole block if over half of it is free */
1007 if (pages >= (1 << (pageblock_order-1)) ||
1008 page_group_by_mobility_disabled)
1009 set_pageblock_migratetype(page,
1012 migratetype = start_migratetype;
1015 /* Remove the page from the freelists */
1016 list_del(&page->lru);
1017 rmv_page_order(page);
1019 /* Take ownership for orders >= pageblock_order */
1020 if (current_order >= pageblock_order)
1021 change_pageblock_range(page, current_order,
1024 expand(zone, page, order, current_order, area, migratetype);
1026 trace_mm_page_alloc_extfrag(page, order, current_order,
1027 start_migratetype, migratetype);
1037 * Do the hard work of removing an element from the buddy allocator.
1038 * Call me with the zone->lock already held.
1040 static struct page *__rmqueue(struct zone *zone, unsigned int order,
1046 page = __rmqueue_smallest(zone, order, migratetype);
1048 if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
1049 page = __rmqueue_fallback(zone, order, migratetype);
1052 * Use MIGRATE_RESERVE rather than fail an allocation. goto
1053 * is used because __rmqueue_smallest is an inline function
1054 * and we want just one call site
1057 migratetype = MIGRATE_RESERVE;
1062 trace_mm_page_alloc_zone_locked(page, order, migratetype);
1067 * Obtain a specified number of elements from the buddy allocator, all under
1068 * a single hold of the lock, for efficiency. Add them to the supplied list.
1069 * Returns the number of new pages which were placed at *list.
1071 static int rmqueue_bulk(struct zone *zone, unsigned int order,
1072 unsigned long count, struct list_head *list,
1073 int migratetype, int cold)
1077 spin_lock(&zone->lock);
1078 for (i = 0; i < count; ++i) {
1079 struct page *page = __rmqueue(zone, order, migratetype);
1080 if (unlikely(page == NULL))
1084 * Split buddy pages returned by expand() are received here
1085 * in physical page order. The page is added to the callers and
1086 * list and the list head then moves forward. From the callers
1087 * perspective, the linked list is ordered by page number in
1088 * some conditions. This is useful for IO devices that can
1089 * merge IO requests if the physical pages are ordered
1092 if (likely(cold == 0))
1093 list_add(&page->lru, list);
1095 list_add_tail(&page->lru, list);
1096 set_page_private(page, migratetype);
1099 __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
1100 spin_unlock(&zone->lock);
1106 * Called from the vmstat counter updater to drain pagesets of this
1107 * currently executing processor on remote nodes after they have
1110 * Note that this function must be called with the thread pinned to
1111 * a single processor.
1113 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
1115 unsigned long flags;
1118 local_irq_save(flags);
1119 if (pcp->count >= pcp->batch)
1120 to_drain = pcp->batch;
1122 to_drain = pcp->count;
1123 free_pcppages_bulk(zone, to_drain, pcp);
1124 pcp->count -= to_drain;
1125 local_irq_restore(flags);
1130 * Drain pages of the indicated processor.
1132 * The processor must either be the current processor and the
1133 * thread pinned to the current processor or a processor that
1136 static void drain_pages(unsigned int cpu)
1138 unsigned long flags;
1141 for_each_populated_zone(zone) {
1142 struct per_cpu_pageset *pset;
1143 struct per_cpu_pages *pcp;
1145 local_irq_save(flags);
1146 pset = per_cpu_ptr(zone->pageset, cpu);
1150 free_pcppages_bulk(zone, pcp->count, pcp);
1153 local_irq_restore(flags);
1158 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
1160 void drain_local_pages(void *arg)
1162 drain_pages(smp_processor_id());
1166 * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
1168 * Note that this code is protected against sending an IPI to an offline
1169 * CPU but does not guarantee sending an IPI to newly hotplugged CPUs:
1170 * on_each_cpu_mask() blocks hotplug and won't talk to offlined CPUs but
1171 * nothing keeps CPUs from showing up after we populated the cpumask and
1172 * before the call to on_each_cpu_mask().
1174 void drain_all_pages(void)
1177 struct per_cpu_pageset *pcp;
1181 * Allocate in the BSS so we wont require allocation in
1182 * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
1184 static cpumask_t cpus_with_pcps;
1187 * We don't care about racing with CPU hotplug event
1188 * as offline notification will cause the notified
1189 * cpu to drain that CPU pcps and on_each_cpu_mask
1190 * disables preemption as part of its processing
1192 for_each_online_cpu(cpu) {
1193 bool has_pcps = false;
1194 for_each_populated_zone(zone) {
1195 pcp = per_cpu_ptr(zone->pageset, cpu);
1196 if (pcp->pcp.count) {
1202 cpumask_set_cpu(cpu, &cpus_with_pcps);
1204 cpumask_clear_cpu(cpu, &cpus_with_pcps);
1206 on_each_cpu_mask(&cpus_with_pcps, drain_local_pages, NULL, 1);
1209 #ifdef CONFIG_HIBERNATION
1211 void mark_free_pages(struct zone *zone)
1213 unsigned long pfn, max_zone_pfn;
1214 unsigned long flags;
1216 struct list_head *curr;
1218 if (!zone->spanned_pages)
1221 spin_lock_irqsave(&zone->lock, flags);
1223 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1224 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1225 if (pfn_valid(pfn)) {
1226 struct page *page = pfn_to_page(pfn);
1228 if (!swsusp_page_is_forbidden(page))
1229 swsusp_unset_page_free(page);
1232 for_each_migratetype_order(order, t) {
1233 list_for_each(curr, &zone->free_area[order].free_list[t]) {
1236 pfn = page_to_pfn(list_entry(curr, struct page, lru));
1237 for (i = 0; i < (1UL << order); i++)
1238 swsusp_set_page_free(pfn_to_page(pfn + i));
1241 spin_unlock_irqrestore(&zone->lock, flags);
1243 #endif /* CONFIG_PM */
1246 * Free a 0-order page
1247 * cold == 1 ? free a cold page : free a hot page
1249 void free_hot_cold_page(struct page *page, int cold)
1251 struct zone *zone = page_zone(page);
1252 struct per_cpu_pages *pcp;
1253 unsigned long flags;
1255 int wasMlocked = __TestClearPageMlocked(page);
1257 if (!free_pages_prepare(page, 0))
1260 migratetype = get_pageblock_migratetype(page);
1261 set_page_private(page, migratetype);
1262 local_irq_save(flags);
1263 if (unlikely(wasMlocked))
1264 free_page_mlock(page);
1265 __count_vm_event(PGFREE);
1268 * We only track unmovable, reclaimable and movable on pcp lists.
1269 * Free ISOLATE pages back to the allocator because they are being
1270 * offlined but treat RESERVE as movable pages so we can get those
1271 * areas back if necessary. Otherwise, we may have to free
1272 * excessively into the page allocator
1274 if (migratetype >= MIGRATE_PCPTYPES) {
1275 if (unlikely(migratetype == MIGRATE_ISOLATE)) {
1276 free_one_page(zone, page, 0, migratetype);
1279 migratetype = MIGRATE_MOVABLE;
1282 pcp = &this_cpu_ptr(zone->pageset)->pcp;
1284 list_add_tail(&page->lru, &pcp->lists[migratetype]);
1286 list_add(&page->lru, &pcp->lists[migratetype]);
1288 if (pcp->count >= pcp->high) {
1289 free_pcppages_bulk(zone, pcp->batch, pcp);
1290 pcp->count -= pcp->batch;
1294 local_irq_restore(flags);
1298 * Free a list of 0-order pages
1300 void free_hot_cold_page_list(struct list_head *list, int cold)
1302 struct page *page, *next;
1304 list_for_each_entry_safe(page, next, list, lru) {
1305 trace_mm_page_free_batched(page, cold);
1306 free_hot_cold_page(page, cold);
1311 * split_page takes a non-compound higher-order page, and splits it into
1312 * n (1<<order) sub-pages: page[0..n]
1313 * Each sub-page must be freed individually.
1315 * Note: this is probably too low level an operation for use in drivers.
1316 * Please consult with lkml before using this in your driver.
1318 void split_page(struct page *page, unsigned int order)
1322 VM_BUG_ON(PageCompound(page));
1323 VM_BUG_ON(!page_count(page));
1325 #ifdef CONFIG_KMEMCHECK
1327 * Split shadow pages too, because free(page[0]) would
1328 * otherwise free the whole shadow.
1330 if (kmemcheck_page_is_tracked(page))
1331 split_page(virt_to_page(page[0].shadow), order);
1334 for (i = 1; i < (1 << order); i++)
1335 set_page_refcounted(page + i);
1339 * Similar to split_page except the page is already free. As this is only
1340 * being used for migration, the migratetype of the block also changes.
1341 * As this is called with interrupts disabled, the caller is responsible
1342 * for calling arch_alloc_page() and kernel_map_page() after interrupts
1345 * Note: this is probably too low level an operation for use in drivers.
1346 * Please consult with lkml before using this in your driver.
1348 int split_free_page(struct page *page)
1351 unsigned long watermark;
1354 BUG_ON(!PageBuddy(page));
1356 zone = page_zone(page);
1357 order = page_order(page);
1359 /* Obey watermarks as if the page was being allocated */
1360 watermark = low_wmark_pages(zone) + (1 << order);
1361 if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
1364 /* Remove page from free list */
1365 list_del(&page->lru);
1366 zone->free_area[order].nr_free--;
1367 rmv_page_order(page);
1368 __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order));
1370 /* Split into individual pages */
1371 set_page_refcounted(page);
1372 split_page(page, order);
1374 if (order >= pageblock_order - 1) {
1375 struct page *endpage = page + (1 << order) - 1;
1376 for (; page < endpage; page += pageblock_nr_pages)
1377 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1384 * Really, prep_compound_page() should be called from __rmqueue_bulk(). But
1385 * we cheat by calling it from here, in the order > 0 path. Saves a branch
1389 struct page *buffered_rmqueue(struct zone *preferred_zone,
1390 struct zone *zone, int order, gfp_t gfp_flags,
1393 unsigned long flags;
1395 int cold = !!(gfp_flags & __GFP_COLD);
1398 if (likely(order == 0)) {
1399 struct per_cpu_pages *pcp;
1400 struct list_head *list;
1402 local_irq_save(flags);
1403 pcp = &this_cpu_ptr(zone->pageset)->pcp;
1404 list = &pcp->lists[migratetype];
1405 if (list_empty(list)) {
1406 pcp->count += rmqueue_bulk(zone, 0,
1409 if (unlikely(list_empty(list)))
1414 page = list_entry(list->prev, struct page, lru);
1416 page = list_entry(list->next, struct page, lru);
1418 list_del(&page->lru);
1421 if (unlikely(gfp_flags & __GFP_NOFAIL)) {
1423 * __GFP_NOFAIL is not to be used in new code.
1425 * All __GFP_NOFAIL callers should be fixed so that they
1426 * properly detect and handle allocation failures.
1428 * We most definitely don't want callers attempting to
1429 * allocate greater than order-1 page units with
1432 WARN_ON_ONCE(order > 1);
1434 spin_lock_irqsave(&zone->lock, flags);
1435 page = __rmqueue(zone, order, migratetype);
1436 spin_unlock(&zone->lock);
1439 __mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
1442 __count_zone_vm_events(PGALLOC, zone, 1 << order);
1443 zone_statistics(preferred_zone, zone, gfp_flags);
1444 local_irq_restore(flags);
1446 VM_BUG_ON(bad_range(zone, page));
1447 if (prep_new_page(page, order, gfp_flags))
1452 local_irq_restore(flags);
1456 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
1457 #define ALLOC_WMARK_MIN WMARK_MIN
1458 #define ALLOC_WMARK_LOW WMARK_LOW
1459 #define ALLOC_WMARK_HIGH WMARK_HIGH
1460 #define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */
1462 /* Mask to get the watermark bits */
1463 #define ALLOC_WMARK_MASK (ALLOC_NO_WATERMARKS-1)
1465 #define ALLOC_HARDER 0x10 /* try to alloc harder */
1466 #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
1467 #define ALLOC_CPUSET 0x40 /* check for correct cpuset */
1469 #ifdef CONFIG_FAIL_PAGE_ALLOC
1472 struct fault_attr attr;
1474 u32 ignore_gfp_highmem;
1475 u32 ignore_gfp_wait;
1477 } fail_page_alloc = {
1478 .attr = FAULT_ATTR_INITIALIZER,
1479 .ignore_gfp_wait = 1,
1480 .ignore_gfp_highmem = 1,
1484 static int __init setup_fail_page_alloc(char *str)
1486 return setup_fault_attr(&fail_page_alloc.attr, str);
1488 __setup("fail_page_alloc=", setup_fail_page_alloc);
1490 static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1492 if (order < fail_page_alloc.min_order)
1494 if (gfp_mask & __GFP_NOFAIL)
1496 if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1498 if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1501 return should_fail(&fail_page_alloc.attr, 1 << order);
1504 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1506 static int __init fail_page_alloc_debugfs(void)
1508 umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1511 dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
1512 &fail_page_alloc.attr);
1514 return PTR_ERR(dir);
1516 if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
1517 &fail_page_alloc.ignore_gfp_wait))
1519 if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1520 &fail_page_alloc.ignore_gfp_highmem))
1522 if (!debugfs_create_u32("min-order", mode, dir,
1523 &fail_page_alloc.min_order))
1528 debugfs_remove_recursive(dir);
1533 late_initcall(fail_page_alloc_debugfs);
1535 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1537 #else /* CONFIG_FAIL_PAGE_ALLOC */
1539 static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1544 #endif /* CONFIG_FAIL_PAGE_ALLOC */
1547 * Return true if free pages are above 'mark'. This takes into account the order
1548 * of the allocation.
1550 static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1551 int classzone_idx, int alloc_flags, long free_pages)
1553 /* free_pages my go negative - that's OK */
1557 free_pages -= (1 << order) - 1;
1558 if (alloc_flags & ALLOC_HIGH)
1560 if (alloc_flags & ALLOC_HARDER)
1563 if (free_pages <= min + z->lowmem_reserve[classzone_idx])
1565 for (o = 0; o < order; o++) {
1566 /* At the next order, this order's pages become unavailable */
1567 free_pages -= z->free_area[o].nr_free << o;
1569 /* Require fewer higher order pages to be free */
1572 if (free_pages <= min)
1578 bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1579 int classzone_idx, int alloc_flags)
1581 return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1582 zone_page_state(z, NR_FREE_PAGES));
1585 bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark,
1586 int classzone_idx, int alloc_flags)
1588 long free_pages = zone_page_state(z, NR_FREE_PAGES);
1590 if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
1591 free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
1593 return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1599 * zlc_setup - Setup for "zonelist cache". Uses cached zone data to
1600 * skip over zones that are not allowed by the cpuset, or that have
1601 * been recently (in last second) found to be nearly full. See further
1602 * comments in mmzone.h. Reduces cache footprint of zonelist scans
1603 * that have to skip over a lot of full or unallowed zones.
1605 * If the zonelist cache is present in the passed in zonelist, then
1606 * returns a pointer to the allowed node mask (either the current
1607 * tasks mems_allowed, or node_states[N_HIGH_MEMORY].)
1609 * If the zonelist cache is not available for this zonelist, does
1610 * nothing and returns NULL.
1612 * If the fullzones BITMAP in the zonelist cache is stale (more than
1613 * a second since last zap'd) then we zap it out (clear its bits.)
1615 * We hold off even calling zlc_setup, until after we've checked the
1616 * first zone in the zonelist, on the theory that most allocations will
1617 * be satisfied from that first zone, so best to examine that zone as
1618 * quickly as we can.
1620 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1622 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1623 nodemask_t *allowednodes; /* zonelist_cache approximation */
1625 zlc = zonelist->zlcache_ptr;
1629 if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1630 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1631 zlc->last_full_zap = jiffies;
1634 allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1635 &cpuset_current_mems_allowed :
1636 &node_states[N_HIGH_MEMORY];
1637 return allowednodes;
1641 * Given 'z' scanning a zonelist, run a couple of quick checks to see
1642 * if it is worth looking at further for free memory:
1643 * 1) Check that the zone isn't thought to be full (doesn't have its
1644 * bit set in the zonelist_cache fullzones BITMAP).
1645 * 2) Check that the zones node (obtained from the zonelist_cache
1646 * z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1647 * Return true (non-zero) if zone is worth looking at further, or
1648 * else return false (zero) if it is not.
1650 * This check -ignores- the distinction between various watermarks,
1651 * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ... If a zone is
1652 * found to be full for any variation of these watermarks, it will
1653 * be considered full for up to one second by all requests, unless
1654 * we are so low on memory on all allowed nodes that we are forced
1655 * into the second scan of the zonelist.
1657 * In the second scan we ignore this zonelist cache and exactly
1658 * apply the watermarks to all zones, even it is slower to do so.
1659 * We are low on memory in the second scan, and should leave no stone
1660 * unturned looking for a free page.
1662 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1663 nodemask_t *allowednodes)
1665 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1666 int i; /* index of *z in zonelist zones */
1667 int n; /* node that zone *z is on */
1669 zlc = zonelist->zlcache_ptr;
1673 i = z - zonelist->_zonerefs;
1676 /* This zone is worth trying if it is allowed but not full */
1677 return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1681 * Given 'z' scanning a zonelist, set the corresponding bit in
1682 * zlc->fullzones, so that subsequent attempts to allocate a page
1683 * from that zone don't waste time re-examining it.
1685 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1687 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1688 int i; /* index of *z in zonelist zones */
1690 zlc = zonelist->zlcache_ptr;
1694 i = z - zonelist->_zonerefs;
1696 set_bit(i, zlc->fullzones);
1700 * clear all zones full, called after direct reclaim makes progress so that
1701 * a zone that was recently full is not skipped over for up to a second
1703 static void zlc_clear_zones_full(struct zonelist *zonelist)
1705 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1707 zlc = zonelist->zlcache_ptr;
1711 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1714 #else /* CONFIG_NUMA */
1716 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1721 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1722 nodemask_t *allowednodes)
1727 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1731 static void zlc_clear_zones_full(struct zonelist *zonelist)
1734 #endif /* CONFIG_NUMA */
1737 * get_page_from_freelist goes through the zonelist trying to allocate
1740 static struct page *
1741 get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1742 struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
1743 struct zone *preferred_zone, int migratetype)
1746 struct page *page = NULL;
1749 nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1750 int zlc_active = 0; /* set if using zonelist_cache */
1751 int did_zlc_setup = 0; /* just call zlc_setup() one time */
1753 classzone_idx = zone_idx(preferred_zone);
1756 * Scan zonelist, looking for a zone with enough free.
1757 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1759 for_each_zone_zonelist_nodemask(zone, z, zonelist,
1760 high_zoneidx, nodemask) {
1761 if (NUMA_BUILD && zlc_active &&
1762 !zlc_zone_worth_trying(zonelist, z, allowednodes))
1764 if ((alloc_flags & ALLOC_CPUSET) &&
1765 !cpuset_zone_allowed_softwall(zone, gfp_mask))
1768 * When allocating a page cache page for writing, we
1769 * want to get it from a zone that is within its dirty
1770 * limit, such that no single zone holds more than its
1771 * proportional share of globally allowed dirty pages.
1772 * The dirty limits take into account the zone's
1773 * lowmem reserves and high watermark so that kswapd
1774 * should be able to balance it without having to
1775 * write pages from its LRU list.
1777 * This may look like it could increase pressure on
1778 * lower zones by failing allocations in higher zones
1779 * before they are full. But the pages that do spill
1780 * over are limited as the lower zones are protected
1781 * by this very same mechanism. It should not become
1782 * a practical burden to them.
1784 * XXX: For now, allow allocations to potentially
1785 * exceed the per-zone dirty limit in the slowpath
1786 * (ALLOC_WMARK_LOW unset) before going into reclaim,
1787 * which is important when on a NUMA setup the allowed
1788 * zones are together not big enough to reach the
1789 * global limit. The proper fix for these situations
1790 * will require awareness of zones in the
1791 * dirty-throttling and the flusher threads.
1793 if ((alloc_flags & ALLOC_WMARK_LOW) &&
1794 (gfp_mask & __GFP_WRITE) && !zone_dirty_ok(zone))
1795 goto this_zone_full;
1797 BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
1798 if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
1802 mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
1803 if (zone_watermark_ok(zone, order, mark,
1804 classzone_idx, alloc_flags))
1807 if (NUMA_BUILD && !did_zlc_setup && nr_online_nodes > 1) {
1809 * we do zlc_setup if there are multiple nodes
1810 * and before considering the first zone allowed
1813 allowednodes = zlc_setup(zonelist, alloc_flags);
1818 if (zone_reclaim_mode == 0)
1819 goto this_zone_full;
1822 * As we may have just activated ZLC, check if the first
1823 * eligible zone has failed zone_reclaim recently.
1825 if (NUMA_BUILD && zlc_active &&
1826 !zlc_zone_worth_trying(zonelist, z, allowednodes))
1829 ret = zone_reclaim(zone, gfp_mask, order);
1831 case ZONE_RECLAIM_NOSCAN:
1834 case ZONE_RECLAIM_FULL:
1835 /* scanned but unreclaimable */
1838 /* did we reclaim enough */
1839 if (!zone_watermark_ok(zone, order, mark,
1840 classzone_idx, alloc_flags))
1841 goto this_zone_full;
1846 page = buffered_rmqueue(preferred_zone, zone, order,
1847 gfp_mask, migratetype);
1852 zlc_mark_zone_full(zonelist, z);
1855 if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
1856 /* Disable zlc cache for second zonelist scan */
1864 * Large machines with many possible nodes should not always dump per-node
1865 * meminfo in irq context.
1867 static inline bool should_suppress_show_mem(void)
1872 ret = in_interrupt();
1877 static DEFINE_RATELIMIT_STATE(nopage_rs,
1878 DEFAULT_RATELIMIT_INTERVAL,
1879 DEFAULT_RATELIMIT_BURST);
1881 void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...)
1883 unsigned int filter = SHOW_MEM_FILTER_NODES;
1885 if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) ||
1886 debug_guardpage_minorder() > 0)
1890 * This documents exceptions given to allocations in certain
1891 * contexts that are allowed to allocate outside current's set
1894 if (!(gfp_mask & __GFP_NOMEMALLOC))
1895 if (test_thread_flag(TIF_MEMDIE) ||
1896 (current->flags & (PF_MEMALLOC | PF_EXITING)))
1897 filter &= ~SHOW_MEM_FILTER_NODES;
1898 if (in_interrupt() || !(gfp_mask & __GFP_WAIT))
1899 filter &= ~SHOW_MEM_FILTER_NODES;
1902 struct va_format vaf;
1905 va_start(args, fmt);
1910 pr_warn("%pV", &vaf);
1915 pr_warn("%s: page allocation failure: order:%d, mode:0x%x\n",
1916 current->comm, order, gfp_mask);
1919 if (!should_suppress_show_mem())
1924 should_alloc_retry(gfp_t gfp_mask, unsigned int order,
1925 unsigned long did_some_progress,
1926 unsigned long pages_reclaimed)
1928 /* Do not loop if specifically requested */
1929 if (gfp_mask & __GFP_NORETRY)
1932 /* Always retry if specifically requested */
1933 if (gfp_mask & __GFP_NOFAIL)
1937 * Suspend converts GFP_KERNEL to __GFP_WAIT which can prevent reclaim
1938 * making forward progress without invoking OOM. Suspend also disables
1939 * storage devices so kswapd will not help. Bail if we are suspending.
1941 if (!did_some_progress && pm_suspended_storage())
1945 * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
1946 * means __GFP_NOFAIL, but that may not be true in other
1949 if (order <= PAGE_ALLOC_COSTLY_ORDER)
1953 * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
1954 * specified, then we retry until we no longer reclaim any pages
1955 * (above), or we've reclaimed an order of pages at least as
1956 * large as the allocation's order. In both cases, if the
1957 * allocation still fails, we stop retrying.
1959 if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
1965 static inline struct page *
1966 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
1967 struct zonelist *zonelist, enum zone_type high_zoneidx,
1968 nodemask_t *nodemask, struct zone *preferred_zone,
1973 /* Acquire the OOM killer lock for the zones in zonelist */
1974 if (!try_set_zonelist_oom(zonelist, gfp_mask)) {
1975 schedule_timeout_uninterruptible(1);
1980 * Go through the zonelist yet one more time, keep very high watermark
1981 * here, this is only to catch a parallel oom killing, we must fail if
1982 * we're still under heavy pressure.
1984 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
1985 order, zonelist, high_zoneidx,
1986 ALLOC_WMARK_HIGH|ALLOC_CPUSET,
1987 preferred_zone, migratetype);
1991 if (!(gfp_mask & __GFP_NOFAIL)) {
1992 /* The OOM killer will not help higher order allocs */
1993 if (order > PAGE_ALLOC_COSTLY_ORDER)
1995 /* The OOM killer does not needlessly kill tasks for lowmem */
1996 if (high_zoneidx < ZONE_NORMAL)
1999 * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
2000 * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
2001 * The caller should handle page allocation failure by itself if
2002 * it specifies __GFP_THISNODE.
2003 * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
2005 if (gfp_mask & __GFP_THISNODE)
2008 /* Exhausted what can be done so it's blamo time */
2009 out_of_memory(zonelist, gfp_mask, order, nodemask, false);
2012 clear_zonelist_oom(zonelist, gfp_mask);
2016 #ifdef CONFIG_COMPACTION
2017 /* Try memory compaction for high-order allocations before reclaim */
2018 static struct page *
2019 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2020 struct zonelist *zonelist, enum zone_type high_zoneidx,
2021 nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2022 int migratetype, bool sync_migration,
2023 bool *deferred_compaction,
2024 unsigned long *did_some_progress)
2031 if (compaction_deferred(preferred_zone, order)) {
2032 *deferred_compaction = true;
2036 current->flags |= PF_MEMALLOC;
2037 *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
2038 nodemask, sync_migration);
2039 current->flags &= ~PF_MEMALLOC;
2040 if (*did_some_progress != COMPACT_SKIPPED) {
2042 /* Page migration frees to the PCP lists but we want merging */
2043 drain_pages(get_cpu());
2046 page = get_page_from_freelist(gfp_mask, nodemask,
2047 order, zonelist, high_zoneidx,
2048 alloc_flags, preferred_zone,
2051 preferred_zone->compact_considered = 0;
2052 preferred_zone->compact_defer_shift = 0;
2053 if (order >= preferred_zone->compact_order_failed)
2054 preferred_zone->compact_order_failed = order + 1;
2055 count_vm_event(COMPACTSUCCESS);
2060 * It's bad if compaction run occurs and fails.
2061 * The most likely reason is that pages exist,
2062 * but not enough to satisfy watermarks.
2064 count_vm_event(COMPACTFAIL);
2067 * As async compaction considers a subset of pageblocks, only
2068 * defer if the failure was a sync compaction failure.
2071 defer_compaction(preferred_zone, order);
2079 static inline struct page *
2080 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2081 struct zonelist *zonelist, enum zone_type high_zoneidx,
2082 nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2083 int migratetype, bool sync_migration,
2084 bool *deferred_compaction,
2085 unsigned long *did_some_progress)
2089 #endif /* CONFIG_COMPACTION */
2091 /* The really slow allocator path where we enter direct reclaim */
2092 static inline struct page *
2093 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
2094 struct zonelist *zonelist, enum zone_type high_zoneidx,
2095 nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2096 int migratetype, unsigned long *did_some_progress)
2098 struct page *page = NULL;
2099 struct reclaim_state reclaim_state;
2100 bool drained = false;
2104 /* We now go into synchronous reclaim */
2105 cpuset_memory_pressure_bump();
2106 current->flags |= PF_MEMALLOC;
2107 lockdep_set_current_reclaim_state(gfp_mask);
2108 reclaim_state.reclaimed_slab = 0;
2109 current->reclaim_state = &reclaim_state;
2111 *did_some_progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
2113 current->reclaim_state = NULL;
2114 lockdep_clear_current_reclaim_state();
2115 current->flags &= ~PF_MEMALLOC;
2119 if (unlikely(!(*did_some_progress)))
2122 /* After successful reclaim, reconsider all zones for allocation */
2124 zlc_clear_zones_full(zonelist);
2127 page = get_page_from_freelist(gfp_mask, nodemask, order,
2128 zonelist, high_zoneidx,
2129 alloc_flags, preferred_zone,
2133 * If an allocation failed after direct reclaim, it could be because
2134 * pages are pinned on the per-cpu lists. Drain them and try again
2136 if (!page && !drained) {
2146 * This is called in the allocator slow-path if the allocation request is of
2147 * sufficient urgency to ignore watermarks and take other desperate measures
2149 static inline struct page *
2150 __alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
2151 struct zonelist *zonelist, enum zone_type high_zoneidx,
2152 nodemask_t *nodemask, struct zone *preferred_zone,
2158 page = get_page_from_freelist(gfp_mask, nodemask, order,
2159 zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
2160 preferred_zone, migratetype);
2162 if (!page && gfp_mask & __GFP_NOFAIL)
2163 wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2164 } while (!page && (gfp_mask & __GFP_NOFAIL));
2170 void wake_all_kswapd(unsigned int order, struct zonelist *zonelist,
2171 enum zone_type high_zoneidx,
2172 enum zone_type classzone_idx)
2177 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
2178 wakeup_kswapd(zone, order, classzone_idx);
2182 gfp_to_alloc_flags(gfp_t gfp_mask)
2184 int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
2185 const gfp_t wait = gfp_mask & __GFP_WAIT;
2187 /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
2188 BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
2191 * The caller may dip into page reserves a bit more if the caller
2192 * cannot run direct reclaim, or if the caller has realtime scheduling
2193 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
2194 * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
2196 alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
2200 * Not worth trying to allocate harder for
2201 * __GFP_NOMEMALLOC even if it can't schedule.
2203 if (!(gfp_mask & __GFP_NOMEMALLOC))
2204 alloc_flags |= ALLOC_HARDER;
2206 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
2207 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
2209 alloc_flags &= ~ALLOC_CPUSET;
2210 } else if (unlikely(rt_task(current)) && !in_interrupt())
2211 alloc_flags |= ALLOC_HARDER;
2213 if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
2214 if (!in_interrupt() &&
2215 ((current->flags & PF_MEMALLOC) ||
2216 unlikely(test_thread_flag(TIF_MEMDIE))))
2217 alloc_flags |= ALLOC_NO_WATERMARKS;
2223 static inline struct page *
2224 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
2225 struct zonelist *zonelist, enum zone_type high_zoneidx,
2226 nodemask_t *nodemask, struct zone *preferred_zone,
2229 const gfp_t wait = gfp_mask & __GFP_WAIT;
2230 struct page *page = NULL;
2232 unsigned long pages_reclaimed = 0;
2233 unsigned long did_some_progress;
2234 bool sync_migration = false;
2235 bool deferred_compaction = false;
2238 * In the slowpath, we sanity check order to avoid ever trying to
2239 * reclaim >= MAX_ORDER areas which will never succeed. Callers may
2240 * be using allocators in order of preference for an area that is
2243 if (order >= MAX_ORDER) {
2244 WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
2249 * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
2250 * __GFP_NOWARN set) should not cause reclaim since the subsystem
2251 * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
2252 * using a larger set of nodes after it has established that the
2253 * allowed per node queues are empty and that nodes are
2256 if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
2260 if (!(gfp_mask & __GFP_NO_KSWAPD))
2261 wake_all_kswapd(order, zonelist, high_zoneidx,
2262 zone_idx(preferred_zone));
2265 * OK, we're below the kswapd watermark and have kicked background
2266 * reclaim. Now things get more complex, so set up alloc_flags according
2267 * to how we want to proceed.
2269 alloc_flags = gfp_to_alloc_flags(gfp_mask);
2272 * Find the true preferred zone if the allocation is unconstrained by
2275 if (!(alloc_flags & ALLOC_CPUSET) && !nodemask)
2276 first_zones_zonelist(zonelist, high_zoneidx, NULL,
2280 /* This is the last chance, in general, before the goto nopage. */
2281 page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
2282 high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
2283 preferred_zone, migratetype);
2287 /* Allocate without watermarks if the context allows */
2288 if (alloc_flags & ALLOC_NO_WATERMARKS) {
2289 page = __alloc_pages_high_priority(gfp_mask, order,
2290 zonelist, high_zoneidx, nodemask,
2291 preferred_zone, migratetype);
2296 /* Atomic allocations - we can't balance anything */
2300 /* Avoid recursion of direct reclaim */
2301 if (current->flags & PF_MEMALLOC)
2304 /* Avoid allocations with no watermarks from looping endlessly */
2305 if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
2309 * Try direct compaction. The first pass is asynchronous. Subsequent
2310 * attempts after direct reclaim are synchronous
2312 page = __alloc_pages_direct_compact(gfp_mask, order,
2313 zonelist, high_zoneidx,
2315 alloc_flags, preferred_zone,
2316 migratetype, sync_migration,
2317 &deferred_compaction,
2318 &did_some_progress);
2321 sync_migration = true;
2324 * If compaction is deferred for high-order allocations, it is because
2325 * sync compaction recently failed. In this is the case and the caller
2326 * has requested the system not be heavily disrupted, fail the
2327 * allocation now instead of entering direct reclaim
2329 if (deferred_compaction && (gfp_mask & __GFP_NO_KSWAPD))
2332 /* Try direct reclaim and then allocating */
2333 page = __alloc_pages_direct_reclaim(gfp_mask, order,
2334 zonelist, high_zoneidx,
2336 alloc_flags, preferred_zone,
2337 migratetype, &did_some_progress);
2342 * If we failed to make any progress reclaiming, then we are
2343 * running out of options and have to consider going OOM
2345 if (!did_some_progress) {
2346 if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
2347 if (oom_killer_disabled)
2349 /* Coredumps can quickly deplete all memory reserves */
2350 if ((current->flags & PF_DUMPCORE) &&
2351 !(gfp_mask & __GFP_NOFAIL))
2353 page = __alloc_pages_may_oom(gfp_mask, order,
2354 zonelist, high_zoneidx,
2355 nodemask, preferred_zone,
2360 if (!(gfp_mask & __GFP_NOFAIL)) {
2362 * The oom killer is not called for high-order
2363 * allocations that may fail, so if no progress
2364 * is being made, there are no other options and
2365 * retrying is unlikely to help.
2367 if (order > PAGE_ALLOC_COSTLY_ORDER)
2370 * The oom killer is not called for lowmem
2371 * allocations to prevent needlessly killing
2374 if (high_zoneidx < ZONE_NORMAL)
2382 /* Check if we should retry the allocation */
2383 pages_reclaimed += did_some_progress;
2384 if (should_alloc_retry(gfp_mask, order, did_some_progress,
2386 /* Wait for some write requests to complete then retry */
2387 wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2391 * High-order allocations do not necessarily loop after
2392 * direct reclaim and reclaim/compaction depends on compaction
2393 * being called after reclaim so call directly if necessary
2395 page = __alloc_pages_direct_compact(gfp_mask, order,
2396 zonelist, high_zoneidx,
2398 alloc_flags, preferred_zone,
2399 migratetype, sync_migration,
2400 &deferred_compaction,
2401 &did_some_progress);
2407 warn_alloc_failed(gfp_mask, order, NULL);
2410 if (kmemcheck_enabled)
2411 kmemcheck_pagealloc_alloc(page, order, gfp_mask);
2417 * This is the 'heart' of the zoned buddy allocator.
2420 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
2421 struct zonelist *zonelist, nodemask_t *nodemask)
2423 enum zone_type high_zoneidx = gfp_zone(gfp_mask);
2424 struct zone *preferred_zone;
2425 struct page *page = NULL;
2426 int migratetype = allocflags_to_migratetype(gfp_mask);
2427 unsigned int cpuset_mems_cookie;
2429 gfp_mask &= gfp_allowed_mask;
2431 lockdep_trace_alloc(gfp_mask);
2433 might_sleep_if(gfp_mask & __GFP_WAIT);
2435 if (should_fail_alloc_page(gfp_mask, order))
2439 * Check the zones suitable for the gfp_mask contain at least one
2440 * valid zone. It's possible to have an empty zonelist as a result
2441 * of GFP_THISNODE and a memoryless node
2443 if (unlikely(!zonelist->_zonerefs->zone))
2447 cpuset_mems_cookie = get_mems_allowed();
2449 /* The preferred zone is used for statistics later */
2450 first_zones_zonelist(zonelist, high_zoneidx,
2451 nodemask ? : &cpuset_current_mems_allowed,
2453 if (!preferred_zone)
2456 /* First allocation attempt */
2457 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
2458 zonelist, high_zoneidx, ALLOC_WMARK_LOW|ALLOC_CPUSET,
2459 preferred_zone, migratetype);
2460 if (unlikely(!page))
2461 page = __alloc_pages_slowpath(gfp_mask, order,
2462 zonelist, high_zoneidx, nodemask,
2463 preferred_zone, migratetype);
2465 trace_mm_page_alloc(page, order, gfp_mask, migratetype);
2469 * When updating a task's mems_allowed, it is possible to race with
2470 * parallel threads in such a way that an allocation can fail while
2471 * the mask is being updated. If a page allocation is about to fail,
2472 * check if the cpuset changed during allocation and if so, retry.
2474 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
2479 EXPORT_SYMBOL(__alloc_pages_nodemask);
2482 * Common helper functions.
2484 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
2489 * __get_free_pages() returns a 32-bit address, which cannot represent
2492 VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
2494 page = alloc_pages(gfp_mask, order);
2497 return (unsigned long) page_address(page);
2499 EXPORT_SYMBOL(__get_free_pages);
2501 unsigned long get_zeroed_page(gfp_t gfp_mask)
2503 return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
2505 EXPORT_SYMBOL(get_zeroed_page);
2507 void __free_pages(struct page *page, unsigned int order)
2509 if (put_page_testzero(page)) {
2511 free_hot_cold_page(page, 0);
2513 __free_pages_ok(page, order);
2517 EXPORT_SYMBOL(__free_pages);
2519 void free_pages(unsigned long addr, unsigned int order)
2522 VM_BUG_ON(!virt_addr_valid((void *)addr));
2523 __free_pages(virt_to_page((void *)addr), order);
2527 EXPORT_SYMBOL(free_pages);
2529 static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
2532 unsigned long alloc_end = addr + (PAGE_SIZE << order);
2533 unsigned long used = addr + PAGE_ALIGN(size);
2535 split_page(virt_to_page((void *)addr), order);
2536 while (used < alloc_end) {
2541 return (void *)addr;
2545 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
2546 * @size: the number of bytes to allocate
2547 * @gfp_mask: GFP flags for the allocation
2549 * This function is similar to alloc_pages(), except that it allocates the
2550 * minimum number of pages to satisfy the request. alloc_pages() can only
2551 * allocate memory in power-of-two pages.
2553 * This function is also limited by MAX_ORDER.
2555 * Memory allocated by this function must be released by free_pages_exact().
2557 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
2559 unsigned int order = get_order(size);
2562 addr = __get_free_pages(gfp_mask, order);
2563 return make_alloc_exact(addr, order, size);
2565 EXPORT_SYMBOL(alloc_pages_exact);
2568 * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
2570 * @nid: the preferred node ID where memory should be allocated
2571 * @size: the number of bytes to allocate
2572 * @gfp_mask: GFP flags for the allocation
2574 * Like alloc_pages_exact(), but try to allocate on node nid first before falling
2576 * Note this is not alloc_pages_exact_node() which allocates on a specific node,
2579 void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
2581 unsigned order = get_order(size);
2582 struct page *p = alloc_pages_node(nid, gfp_mask, order);
2585 return make_alloc_exact((unsigned long)page_address(p), order, size);
2587 EXPORT_SYMBOL(alloc_pages_exact_nid);
2590 * free_pages_exact - release memory allocated via alloc_pages_exact()
2591 * @virt: the value returned by alloc_pages_exact.
2592 * @size: size of allocation, same value as passed to alloc_pages_exact().
2594 * Release the memory allocated by a previous call to alloc_pages_exact.
2596 void free_pages_exact(void *virt, size_t size)
2598 unsigned long addr = (unsigned long)virt;
2599 unsigned long end = addr + PAGE_ALIGN(size);
2601 while (addr < end) {
2606 EXPORT_SYMBOL(free_pages_exact);
2608 static unsigned int nr_free_zone_pages(int offset)
2613 /* Just pick one node, since fallback list is circular */
2614 unsigned int sum = 0;
2616 struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
2618 for_each_zone_zonelist(zone, z, zonelist, offset) {
2619 unsigned long size = zone->present_pages;
2620 unsigned long high = high_wmark_pages(zone);
2629 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
2631 unsigned int nr_free_buffer_pages(void)
2633 return nr_free_zone_pages(gfp_zone(GFP_USER));
2635 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
2638 * Amount of free RAM allocatable within all zones
2640 unsigned int nr_free_pagecache_pages(void)
2642 return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
2645 static inline void show_node(struct zone *zone)
2648 printk("Node %d ", zone_to_nid(zone));
2651 void si_meminfo(struct sysinfo *val)
2653 val->totalram = totalram_pages;
2655 val->freeram = global_page_state(NR_FREE_PAGES);
2656 val->bufferram = nr_blockdev_pages();
2657 val->totalhigh = totalhigh_pages;
2658 val->freehigh = nr_free_highpages();
2659 val->mem_unit = PAGE_SIZE;
2662 EXPORT_SYMBOL(si_meminfo);
2665 void si_meminfo_node(struct sysinfo *val, int nid)
2667 pg_data_t *pgdat = NODE_DATA(nid);
2669 val->totalram = pgdat->node_present_pages;
2670 val->freeram = node_page_state(nid, NR_FREE_PAGES);
2671 #ifdef CONFIG_HIGHMEM
2672 val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
2673 val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
2679 val->mem_unit = PAGE_SIZE;
2684 * Determine whether the node should be displayed or not, depending on whether
2685 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
2687 bool skip_free_areas_node(unsigned int flags, int nid)
2690 unsigned int cpuset_mems_cookie;
2692 if (!(flags & SHOW_MEM_FILTER_NODES))
2696 cpuset_mems_cookie = get_mems_allowed();
2697 ret = !node_isset(nid, cpuset_current_mems_allowed);
2698 } while (!put_mems_allowed(cpuset_mems_cookie));
2703 #define K(x) ((x) << (PAGE_SHIFT-10))
2706 * Show free area list (used inside shift_scroll-lock stuff)
2707 * We also calculate the percentage fragmentation. We do this by counting the
2708 * memory on each free list with the exception of the first item on the list.
2709 * Suppresses nodes that are not allowed by current's cpuset if
2710 * SHOW_MEM_FILTER_NODES is passed.
2712 void show_free_areas(unsigned int filter)
2717 for_each_populated_zone(zone) {
2718 if (skip_free_areas_node(filter, zone_to_nid(zone)))
2721 printk("%s per-cpu:\n", zone->name);
2723 for_each_online_cpu(cpu) {
2724 struct per_cpu_pageset *pageset;
2726 pageset = per_cpu_ptr(zone->pageset, cpu);
2728 printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
2729 cpu, pageset->pcp.high,
2730 pageset->pcp.batch, pageset->pcp.count);
2734 printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
2735 " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
2737 " dirty:%lu writeback:%lu unstable:%lu\n"
2738 " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
2739 " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n",
2740 global_page_state(NR_ACTIVE_ANON),
2741 global_page_state(NR_INACTIVE_ANON),
2742 global_page_state(NR_ISOLATED_ANON),
2743 global_page_state(NR_ACTIVE_FILE),
2744 global_page_state(NR_INACTIVE_FILE),
2745 global_page_state(NR_ISOLATED_FILE),
2746 global_page_state(NR_UNEVICTABLE),
2747 global_page_state(NR_FILE_DIRTY),
2748 global_page_state(NR_WRITEBACK),
2749 global_page_state(NR_UNSTABLE_NFS),
2750 global_page_state(NR_FREE_PAGES),
2751 global_page_state(NR_SLAB_RECLAIMABLE),
2752 global_page_state(NR_SLAB_UNRECLAIMABLE),
2753 global_page_state(NR_FILE_MAPPED),
2754 global_page_state(NR_SHMEM),
2755 global_page_state(NR_PAGETABLE),
2756 global_page_state(NR_BOUNCE));
2758 for_each_populated_zone(zone) {
2761 if (skip_free_areas_node(filter, zone_to_nid(zone)))
2769 " active_anon:%lukB"
2770 " inactive_anon:%lukB"
2771 " active_file:%lukB"
2772 " inactive_file:%lukB"
2773 " unevictable:%lukB"
2774 " isolated(anon):%lukB"
2775 " isolated(file):%lukB"
2782 " slab_reclaimable:%lukB"
2783 " slab_unreclaimable:%lukB"
2784 " kernel_stack:%lukB"
2788 " writeback_tmp:%lukB"
2789 " pages_scanned:%lu"
2790 " all_unreclaimable? %s"
2793 K(zone_page_state(zone, NR_FREE_PAGES)),
2794 K(min_wmark_pages(zone)),
2795 K(low_wmark_pages(zone)),
2796 K(high_wmark_pages(zone)),
2797 K(zone_page_state(zone, NR_ACTIVE_ANON)),
2798 K(zone_page_state(zone, NR_INACTIVE_ANON)),
2799 K(zone_page_state(zone, NR_ACTIVE_FILE)),
2800 K(zone_page_state(zone, NR_INACTIVE_FILE)),
2801 K(zone_page_state(zone, NR_UNEVICTABLE)),
2802 K(zone_page_state(zone, NR_ISOLATED_ANON)),
2803 K(zone_page_state(zone, NR_ISOLATED_FILE)),
2804 K(zone->present_pages),
2805 K(zone_page_state(zone, NR_MLOCK)),
2806 K(zone_page_state(zone, NR_FILE_DIRTY)),
2807 K(zone_page_state(zone, NR_WRITEBACK)),
2808 K(zone_page_state(zone, NR_FILE_MAPPED)),
2809 K(zone_page_state(zone, NR_SHMEM)),
2810 K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
2811 K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
2812 zone_page_state(zone, NR_KERNEL_STACK) *
2814 K(zone_page_state(zone, NR_PAGETABLE)),
2815 K(zone_page_state(zone, NR_UNSTABLE_NFS)),
2816 K(zone_page_state(zone, NR_BOUNCE)),
2817 K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
2818 zone->pages_scanned,
2819 (zone->all_unreclaimable ? "yes" : "no")
2821 printk("lowmem_reserve[]:");
2822 for (i = 0; i < MAX_NR_ZONES; i++)
2823 printk(" %lu", zone->lowmem_reserve[i]);
2827 for_each_populated_zone(zone) {
2828 unsigned long nr[MAX_ORDER], flags, order, total = 0;
2830 if (skip_free_areas_node(filter, zone_to_nid(zone)))
2833 printk("%s: ", zone->name);
2835 spin_lock_irqsave(&zone->lock, flags);
2836 for (order = 0; order < MAX_ORDER; order++) {
2837 nr[order] = zone->free_area[order].nr_free;
2838 total += nr[order] << order;
2840 spin_unlock_irqrestore(&zone->lock, flags);
2841 for (order = 0; order < MAX_ORDER; order++)
2842 printk("%lu*%lukB ", nr[order], K(1UL) << order);
2843 printk("= %lukB\n", K(total));
2846 printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
2848 show_swap_cache_info();
2851 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
2853 zoneref->zone = zone;
2854 zoneref->zone_idx = zone_idx(zone);
2858 * Builds allocation fallback zone lists.
2860 * Add all populated zones of a node to the zonelist.
2862 static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
2863 int nr_zones, enum zone_type zone_type)
2867 BUG_ON(zone_type >= MAX_NR_ZONES);
2872 zone = pgdat->node_zones + zone_type;
2873 if (populated_zone(zone)) {
2874 zoneref_set_zone(zone,
2875 &zonelist->_zonerefs[nr_zones++]);
2876 check_highest_zone(zone_type);
2879 } while (zone_type);
2886 * 0 = automatic detection of better ordering.
2887 * 1 = order by ([node] distance, -zonetype)
2888 * 2 = order by (-zonetype, [node] distance)
2890 * If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
2891 * the same zonelist. So only NUMA can configure this param.
2893 #define ZONELIST_ORDER_DEFAULT 0
2894 #define ZONELIST_ORDER_NODE 1
2895 #define ZONELIST_ORDER_ZONE 2
2897 /* zonelist order in the kernel.
2898 * set_zonelist_order() will set this to NODE or ZONE.
2900 static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
2901 static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
2905 /* The value user specified ....changed by config */
2906 static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2907 /* string for sysctl */
2908 #define NUMA_ZONELIST_ORDER_LEN 16
2909 char numa_zonelist_order[16] = "default";
2912 * interface for configure zonelist ordering.
2913 * command line option "numa_zonelist_order"
2914 * = "[dD]efault - default, automatic configuration.
2915 * = "[nN]ode - order by node locality, then by zone within node
2916 * = "[zZ]one - order by zone, then by locality within zone
2919 static int __parse_numa_zonelist_order(char *s)
2921 if (*s == 'd' || *s == 'D') {
2922 user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2923 } else if (*s == 'n' || *s == 'N') {
2924 user_zonelist_order = ZONELIST_ORDER_NODE;
2925 } else if (*s == 'z' || *s == 'Z') {
2926 user_zonelist_order = ZONELIST_ORDER_ZONE;
2929 "Ignoring invalid numa_zonelist_order value: "
2936 static __init int setup_numa_zonelist_order(char *s)
2943 ret = __parse_numa_zonelist_order(s);
2945 strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
2949 early_param("numa_zonelist_order", setup_numa_zonelist_order);
2952 * sysctl handler for numa_zonelist_order
2954 int numa_zonelist_order_handler(ctl_table *table, int write,
2955 void __user *buffer, size_t *length,
2958 char saved_string[NUMA_ZONELIST_ORDER_LEN];
2960 static DEFINE_MUTEX(zl_order_mutex);
2962 mutex_lock(&zl_order_mutex);
2964 strcpy(saved_string, (char*)table->data);
2965 ret = proc_dostring(table, write, buffer, length, ppos);
2969 int oldval = user_zonelist_order;
2970 if (__parse_numa_zonelist_order((char*)table->data)) {
2972 * bogus value. restore saved string
2974 strncpy((char*)table->data, saved_string,
2975 NUMA_ZONELIST_ORDER_LEN);
2976 user_zonelist_order = oldval;
2977 } else if (oldval != user_zonelist_order) {
2978 mutex_lock(&zonelists_mutex);
2979 build_all_zonelists(NULL);
2980 mutex_unlock(&zonelists_mutex);
2984 mutex_unlock(&zl_order_mutex);
2989 #define MAX_NODE_LOAD (nr_online_nodes)
2990 static int node_load[MAX_NUMNODES];
2993 * find_next_best_node - find the next node that should appear in a given node's fallback list
2994 * @node: node whose fallback list we're appending
2995 * @used_node_mask: nodemask_t of already used nodes
2997 * We use a number of factors to determine which is the next node that should
2998 * appear on a given node's fallback list. The node should not have appeared
2999 * already in @node's fallback list, and it should be the next closest node
3000 * according to the distance array (which contains arbitrary distance values
3001 * from each node to each node in the system), and should also prefer nodes
3002 * with no CPUs, since presumably they'll have very little allocation pressure
3003 * on them otherwise.
3004 * It returns -1 if no node is found.
3006 static int find_next_best_node(int node, nodemask_t *used_node_mask)
3009 int min_val = INT_MAX;
3011 const struct cpumask *tmp = cpumask_of_node(0);
3013 /* Use the local node if we haven't already */
3014 if (!node_isset(node, *used_node_mask)) {
3015 node_set(node, *used_node_mask);
3019 for_each_node_state(n, N_HIGH_MEMORY) {
3021 /* Don't want a node to appear more than once */
3022 if (node_isset(n, *used_node_mask))
3025 /* Use the distance array to find the distance */
3026 val = node_distance(node, n);
3028 /* Penalize nodes under us ("prefer the next node") */
3031 /* Give preference to headless and unused nodes */
3032 tmp = cpumask_of_node(n);
3033 if (!cpumask_empty(tmp))
3034 val += PENALTY_FOR_NODE_WITH_CPUS;
3036 /* Slight preference for less loaded node */
3037 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
3038 val += node_load[n];
3040 if (val < min_val) {
3047 node_set(best_node, *used_node_mask);
3054 * Build zonelists ordered by node and zones within node.
3055 * This results in maximum locality--normal zone overflows into local
3056 * DMA zone, if any--but risks exhausting DMA zone.
3058 static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
3061 struct zonelist *zonelist;
3063 zonelist = &pgdat->node_zonelists[0];
3064 for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
3066 j = build_zonelists_node(NODE_DATA(node), zonelist, j,
3068 zonelist->_zonerefs[j].zone = NULL;
3069 zonelist->_zonerefs[j].zone_idx = 0;
3073 * Build gfp_thisnode zonelists
3075 static void build_thisnode_zonelists(pg_data_t *pgdat)
3078 struct zonelist *zonelist;
3080 zonelist = &pgdat->node_zonelists[1];
3081 j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
3082 zonelist->_zonerefs[j].zone = NULL;
3083 zonelist->_zonerefs[j].zone_idx = 0;
3087 * Build zonelists ordered by zone and nodes within zones.
3088 * This results in conserving DMA zone[s] until all Normal memory is
3089 * exhausted, but results in overflowing to remote node while memory
3090 * may still exist in local DMA zone.
3092 static int node_order[MAX_NUMNODES];
3094 static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
3097 int zone_type; /* needs to be signed */
3099 struct zonelist *zonelist;
3101 zonelist = &pgdat->node_zonelists[0];
3103 for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
3104 for (j = 0; j < nr_nodes; j++) {
3105 node = node_order[j];
3106 z = &NODE_DATA(node)->node_zones[zone_type];
3107 if (populated_zone(z)) {
3109 &zonelist->_zonerefs[pos++]);
3110 check_highest_zone(zone_type);
3114 zonelist->_zonerefs[pos].zone = NULL;
3115 zonelist->_zonerefs[pos].zone_idx = 0;
3118 static int default_zonelist_order(void)
3121 unsigned long low_kmem_size,total_size;
3125 * ZONE_DMA and ZONE_DMA32 can be very small area in the system.
3126 * If they are really small and used heavily, the system can fall
3127 * into OOM very easily.
3128 * This function detect ZONE_DMA/DMA32 size and configures zone order.
3130 /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
3133 for_each_online_node(nid) {
3134 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3135 z = &NODE_DATA(nid)->node_zones[zone_type];
3136 if (populated_zone(z)) {
3137 if (zone_type < ZONE_NORMAL)
3138 low_kmem_size += z->present_pages;
3139 total_size += z->present_pages;
3140 } else if (zone_type == ZONE_NORMAL) {
3142 * If any node has only lowmem, then node order
3143 * is preferred to allow kernel allocations
3144 * locally; otherwise, they can easily infringe
3145 * on other nodes when there is an abundance of
3146 * lowmem available to allocate from.
3148 return ZONELIST_ORDER_NODE;
3152 if (!low_kmem_size || /* there are no DMA area. */
3153 low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
3154 return ZONELIST_ORDER_NODE;
3156 * look into each node's config.
3157 * If there is a node whose DMA/DMA32 memory is very big area on
3158 * local memory, NODE_ORDER may be suitable.
3160 average_size = total_size /
3161 (nodes_weight(node_states[N_HIGH_MEMORY]) + 1);
3162 for_each_online_node(nid) {
3165 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3166 z = &NODE_DATA(nid)->node_zones[zone_type];
3167 if (populated_zone(z)) {
3168 if (zone_type < ZONE_NORMAL)
3169 low_kmem_size += z->present_pages;
3170 total_size += z->present_pages;
3173 if (low_kmem_size &&
3174 total_size > average_size && /* ignore small node */
3175 low_kmem_size > total_size * 70/100)
3176 return ZONELIST_ORDER_NODE;
3178 return ZONELIST_ORDER_ZONE;
3181 static void set_zonelist_order(void)
3183 if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
3184 current_zonelist_order = default_zonelist_order();
3186 current_zonelist_order = user_zonelist_order;
3189 static void build_zonelists(pg_data_t *pgdat)
3193 nodemask_t used_mask;
3194 int local_node, prev_node;
3195 struct zonelist *zonelist;
3196 int order = current_zonelist_order;
3198 /* initialize zonelists */
3199 for (i = 0; i < MAX_ZONELISTS; i++) {
3200 zonelist = pgdat->node_zonelists + i;
3201 zonelist->_zonerefs[0].zone = NULL;
3202 zonelist->_zonerefs[0].zone_idx = 0;
3205 /* NUMA-aware ordering of nodes */
3206 local_node = pgdat->node_id;
3207 load = nr_online_nodes;
3208 prev_node = local_node;
3209 nodes_clear(used_mask);
3211 memset(node_order, 0, sizeof(node_order));
3214 while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
3215 int distance = node_distance(local_node, node);
3218 * If another node is sufficiently far away then it is better
3219 * to reclaim pages in a zone before going off node.
3221 if (distance > RECLAIM_DISTANCE)
3222 zone_reclaim_mode = 1;
3225 * We don't want to pressure a particular node.
3226 * So adding penalty to the first node in same
3227 * distance group to make it round-robin.
3229 if (distance != node_distance(local_node, prev_node))
3230 node_load[node] = load;
3234 if (order == ZONELIST_ORDER_NODE)
3235 build_zonelists_in_node_order(pgdat, node);
3237 node_order[j++] = node; /* remember order */
3240 if (order == ZONELIST_ORDER_ZONE) {
3241 /* calculate node order -- i.e., DMA last! */
3242 build_zonelists_in_zone_order(pgdat, j);
3245 build_thisnode_zonelists(pgdat);
3248 /* Construct the zonelist performance cache - see further mmzone.h */
3249 static void build_zonelist_cache(pg_data_t *pgdat)
3251 struct zonelist *zonelist;
3252 struct zonelist_cache *zlc;
3255 zonelist = &pgdat->node_zonelists[0];
3256 zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
3257 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
3258 for (z = zonelist->_zonerefs; z->zone; z++)
3259 zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
3262 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
3264 * Return node id of node used for "local" allocations.
3265 * I.e., first node id of first zone in arg node's generic zonelist.
3266 * Used for initializing percpu 'numa_mem', which is used primarily
3267 * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
3269 int local_memory_node(int node)
3273 (void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
3274 gfp_zone(GFP_KERNEL),
3281 #else /* CONFIG_NUMA */
3283 static void set_zonelist_order(void)
3285 current_zonelist_order = ZONELIST_ORDER_ZONE;
3288 static void build_zonelists(pg_data_t *pgdat)
3290 int node, local_node;
3292 struct zonelist *zonelist;
3294 local_node = pgdat->node_id;
3296 zonelist = &pgdat->node_zonelists[0];
3297 j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
3300 * Now we build the zonelist so that it contains the zones
3301 * of all the other nodes.
3302 * We don't want to pressure a particular node, so when
3303 * building the zones for node N, we make sure that the
3304 * zones coming right after the local ones are those from
3305 * node N+1 (modulo N)
3307 for (node = local_node + 1; node < MAX_NUMNODES; node++) {
3308 if (!node_online(node))
3310 j = build_zonelists_node(NODE_DATA(node), zonelist, j,
3313 for (node = 0; node < local_node; node++) {
3314 if (!node_online(node))
3316 j = build_zonelists_node(NODE_DATA(node), zonelist, j,
3320 zonelist->_zonerefs[j].zone = NULL;
3321 zonelist->_zonerefs[j].zone_idx = 0;
3324 /* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
3325 static void build_zonelist_cache(pg_data_t *pgdat)
3327 pgdat->node_zonelists[0].zlcache_ptr = NULL;
3330 #endif /* CONFIG_NUMA */
3333 * Boot pageset table. One per cpu which is going to be used for all
3334 * zones and all nodes. The parameters will be set in such a way
3335 * that an item put on a list will immediately be handed over to
3336 * the buddy list. This is safe since pageset manipulation is done
3337 * with interrupts disabled.
3339 * The boot_pagesets must be kept even after bootup is complete for
3340 * unused processors and/or zones. They do play a role for bootstrapping
3341 * hotplugged processors.
3343 * zoneinfo_show() and maybe other functions do
3344 * not check if the processor is online before following the pageset pointer.
3345 * Other parts of the kernel may not check if the zone is available.
3347 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
3348 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
3349 static void setup_zone_pageset(struct zone *zone);
3352 * Global mutex to protect against size modification of zonelists
3353 * as well as to serialize pageset setup for the new populated zone.
3355 DEFINE_MUTEX(zonelists_mutex);
3357 /* return values int ....just for stop_machine() */
3358 static __init_refok int __build_all_zonelists(void *data)
3364 memset(node_load, 0, sizeof(node_load));
3366 for_each_online_node(nid) {
3367 pg_data_t *pgdat = NODE_DATA(nid);
3369 build_zonelists(pgdat);
3370 build_zonelist_cache(pgdat);
3374 * Initialize the boot_pagesets that are going to be used
3375 * for bootstrapping processors. The real pagesets for
3376 * each zone will be allocated later when the per cpu
3377 * allocator is available.
3379 * boot_pagesets are used also for bootstrapping offline
3380 * cpus if the system is already booted because the pagesets
3381 * are needed to initialize allocators on a specific cpu too.
3382 * F.e. the percpu allocator needs the page allocator which
3383 * needs the percpu allocator in order to allocate its pagesets
3384 * (a chicken-egg dilemma).
3386 for_each_possible_cpu(cpu) {
3387 setup_pageset(&per_cpu(boot_pageset, cpu), 0);
3389 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
3391 * We now know the "local memory node" for each node--
3392 * i.e., the node of the first zone in the generic zonelist.
3393 * Set up numa_mem percpu variable for on-line cpus. During
3394 * boot, only the boot cpu should be on-line; we'll init the
3395 * secondary cpus' numa_mem as they come on-line. During
3396 * node/memory hotplug, we'll fixup all on-line cpus.
3398 if (cpu_online(cpu))
3399 set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
3407 * Called with zonelists_mutex held always
3408 * unless system_state == SYSTEM_BOOTING.
3410 void __ref build_all_zonelists(void *data)
3412 set_zonelist_order();
3414 if (system_state == SYSTEM_BOOTING) {
3415 __build_all_zonelists(NULL);
3416 mminit_verify_zonelist();
3417 cpuset_init_current_mems_allowed();
3419 /* we have to stop all cpus to guarantee there is no user
3421 #ifdef CONFIG_MEMORY_HOTPLUG
3423 setup_zone_pageset((struct zone *)data);
3425 stop_machine(__build_all_zonelists, NULL, NULL);
3426 /* cpuset refresh routine should be here */
3428 vm_total_pages = nr_free_pagecache_pages();
3430 * Disable grouping by mobility if the number of pages in the
3431 * system is too low to allow the mechanism to work. It would be
3432 * more accurate, but expensive to check per-zone. This check is
3433 * made on memory-hotadd so a system can start with mobility
3434 * disabled and enable it later
3436 if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
3437 page_group_by_mobility_disabled = 1;
3439 page_group_by_mobility_disabled = 0;
3441 printk("Built %i zonelists in %s order, mobility grouping %s. "
3442 "Total pages: %ld\n",
3444 zonelist_order_name[current_zonelist_order],
3445 page_group_by_mobility_disabled ? "off" : "on",
3448 printk("Policy zone: %s\n", zone_names[policy_zone]);
3453 * Helper functions to size the waitqueue hash table.
3454 * Essentially these want to choose hash table sizes sufficiently
3455 * large so that collisions trying to wait on pages are rare.
3456 * But in fact, the number of active page waitqueues on typical
3457 * systems is ridiculously low, less than 200. So this is even
3458 * conservative, even though it seems large.
3460 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
3461 * waitqueues, i.e. the size of the waitq table given the number of pages.
3463 #define PAGES_PER_WAITQUEUE 256
3465 #ifndef CONFIG_MEMORY_HOTPLUG
3466 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3468 unsigned long size = 1;
3470 pages /= PAGES_PER_WAITQUEUE;
3472 while (size < pages)
3476 * Once we have dozens or even hundreds of threads sleeping
3477 * on IO we've got bigger problems than wait queue collision.
3478 * Limit the size of the wait table to a reasonable size.
3480 size = min(size, 4096UL);
3482 return max(size, 4UL);
3486 * A zone's size might be changed by hot-add, so it is not possible to determine
3487 * a suitable size for its wait_table. So we use the maximum size now.
3489 * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie:
3491 * i386 (preemption config) : 4096 x 16 = 64Kbyte.
3492 * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
3493 * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte.
3495 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
3496 * or more by the traditional way. (See above). It equals:
3498 * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte.
3499 * ia64(16K page size) : = ( 8G + 4M)byte.
3500 * powerpc (64K page size) : = (32G +16M)byte.
3502 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3509 * This is an integer logarithm so that shifts can be used later
3510 * to extract the more random high bits from the multiplicative
3511 * hash function before the remainder is taken.
3513 static inline unsigned long wait_table_bits(unsigned long size)
3518 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
3521 * Check if a pageblock contains reserved pages
3523 static int pageblock_is_reserved(unsigned long start_pfn, unsigned long end_pfn)
3527 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3528 if (!pfn_valid_within(pfn) || PageReserved(pfn_to_page(pfn)))
3535 * Mark a number of pageblocks as MIGRATE_RESERVE. The number
3536 * of blocks reserved is based on min_wmark_pages(zone). The memory within
3537 * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
3538 * higher will lead to a bigger reserve which will get freed as contiguous
3539 * blocks as reclaim kicks in
3541 static void setup_zone_migrate_reserve(struct zone *zone)
3543 unsigned long start_pfn, pfn, end_pfn, block_end_pfn;
3545 unsigned long block_migratetype;
3549 * Get the start pfn, end pfn and the number of blocks to reserve
3550 * We have to be careful to be aligned to pageblock_nr_pages to
3551 * make sure that we always check pfn_valid for the first page in
3554 start_pfn = zone->zone_start_pfn;
3555 end_pfn = start_pfn + zone->spanned_pages;
3556 start_pfn = roundup(start_pfn, pageblock_nr_pages);
3557 reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
3561 * Reserve blocks are generally in place to help high-order atomic
3562 * allocations that are short-lived. A min_free_kbytes value that
3563 * would result in more than 2 reserve blocks for atomic allocations
3564 * is assumed to be in place to help anti-fragmentation for the
3565 * future allocation of hugepages at runtime.
3567 reserve = min(2, reserve);
3569 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
3570 if (!pfn_valid(pfn))
3572 page = pfn_to_page(pfn);
3574 /* Watch out for overlapping nodes */
3575 if (page_to_nid(page) != zone_to_nid(zone))
3578 block_migratetype = get_pageblock_migratetype(page);
3580 /* Only test what is necessary when the reserves are not met */
3583 * Blocks with reserved pages will never free, skip
3586 block_end_pfn = min(pfn + pageblock_nr_pages, end_pfn);
3587 if (pageblock_is_reserved(pfn, block_end_pfn))
3590 /* If this block is reserved, account for it */
3591 if (block_migratetype == MIGRATE_RESERVE) {
3596 /* Suitable for reserving if this block is movable */
3597 if (block_migratetype == MIGRATE_MOVABLE) {
3598 set_pageblock_migratetype(page,
3600 move_freepages_block(zone, page,
3608 * If the reserve is met and this is a previous reserved block,
3611 if (block_migratetype == MIGRATE_RESERVE) {
3612 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3613 move_freepages_block(zone, page, MIGRATE_MOVABLE);
3619 * Initially all pages are reserved - free ones are freed
3620 * up by free_all_bootmem() once the early boot process is
3621 * done. Non-atomic initialization, single-pass.
3623 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
3624 unsigned long start_pfn, enum memmap_context context)
3627 unsigned long end_pfn = start_pfn + size;
3631 if (highest_memmap_pfn < end_pfn - 1)
3632 highest_memmap_pfn = end_pfn - 1;
3634 z = &NODE_DATA(nid)->node_zones[zone];
3635 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3637 * There can be holes in boot-time mem_map[]s
3638 * handed to this function. They do not
3639 * exist on hotplugged memory.
3641 if (context == MEMMAP_EARLY) {
3642 if (!early_pfn_valid(pfn))
3644 if (!early_pfn_in_nid(pfn, nid))
3647 page = pfn_to_page(pfn);
3648 set_page_links(page, zone, nid, pfn);
3649 mminit_verify_page_links(page, zone, nid, pfn);
3650 init_page_count(page);
3651 reset_page_mapcount(page);
3652 SetPageReserved(page);
3654 * Mark the block movable so that blocks are reserved for
3655 * movable at startup. This will force kernel allocations
3656 * to reserve their blocks rather than leaking throughout
3657 * the address space during boot when many long-lived
3658 * kernel allocations are made. Later some blocks near
3659 * the start are marked MIGRATE_RESERVE by
3660 * setup_zone_migrate_reserve()
3662 * bitmap is created for zone's valid pfn range. but memmap
3663 * can be created for invalid pages (for alignment)
3664 * check here not to call set_pageblock_migratetype() against
3667 if ((z->zone_start_pfn <= pfn)
3668 && (pfn < z->zone_start_pfn + z->spanned_pages)
3669 && !(pfn & (pageblock_nr_pages - 1)))
3670 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3672 INIT_LIST_HEAD(&page->lru);
3673 #ifdef WANT_PAGE_VIRTUAL
3674 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
3675 if (!is_highmem_idx(zone))
3676 set_page_address(page, __va(pfn << PAGE_SHIFT));
3681 static void __meminit zone_init_free_lists(struct zone *zone)
3684 for_each_migratetype_order(order, t) {
3685 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
3686 zone->free_area[order].nr_free = 0;
3690 #ifndef __HAVE_ARCH_MEMMAP_INIT
3691 #define memmap_init(size, nid, zone, start_pfn) \
3692 memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
3695 static int zone_batchsize(struct zone *zone)
3701 * The per-cpu-pages pools are set to around 1000th of the
3702 * size of the zone. But no more than 1/2 of a meg.
3704 * OK, so we don't know how big the cache is. So guess.
3706 batch = zone->present_pages / 1024;
3707 if (batch * PAGE_SIZE > 512 * 1024)
3708 batch = (512 * 1024) / PAGE_SIZE;
3709 batch /= 4; /* We effectively *= 4 below */
3714 * Clamp the batch to a 2^n - 1 value. Having a power
3715 * of 2 value was found to be more likely to have
3716 * suboptimal cache aliasing properties in some cases.
3718 * For example if 2 tasks are alternately allocating
3719 * batches of pages, one task can end up with a lot
3720 * of pages of one half of the possible page colors
3721 * and the other with pages of the other colors.
3723 batch = rounddown_pow_of_two(batch + batch/2) - 1;
3728 /* The deferral and batching of frees should be suppressed under NOMMU
3731 * The problem is that NOMMU needs to be able to allocate large chunks
3732 * of contiguous memory as there's no hardware page translation to
3733 * assemble apparent contiguous memory from discontiguous pages.
3735 * Queueing large contiguous runs of pages for batching, however,
3736 * causes the pages to actually be freed in smaller chunks. As there
3737 * can be a significant delay between the individual batches being
3738 * recycled, this leads to the once large chunks of space being
3739 * fragmented and becoming unavailable for high-order allocations.
3745 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
3747 struct per_cpu_pages *pcp;
3750 memset(p, 0, sizeof(*p));
3754 pcp->high = 6 * batch;
3755 pcp->batch = max(1UL, 1 * batch);
3756 for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
3757 INIT_LIST_HEAD(&pcp->lists[migratetype]);
3761 * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
3762 * to the value high for the pageset p.
3765 static void setup_pagelist_highmark(struct per_cpu_pageset *p,
3768 struct per_cpu_pages *pcp;
3772 pcp->batch = max(1UL, high/4);
3773 if ((high/4) > (PAGE_SHIFT * 8))
3774 pcp->batch = PAGE_SHIFT * 8;
3777 static void setup_zone_pageset(struct zone *zone)
3781 zone->pageset = alloc_percpu(struct per_cpu_pageset);
3783 for_each_possible_cpu(cpu) {
3784 struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
3786 setup_pageset(pcp, zone_batchsize(zone));
3788 if (percpu_pagelist_fraction)
3789 setup_pagelist_highmark(pcp,
3790 (zone->present_pages /
3791 percpu_pagelist_fraction));
3796 * Allocate per cpu pagesets and initialize them.
3797 * Before this call only boot pagesets were available.
3799 void __init setup_per_cpu_pageset(void)
3803 for_each_populated_zone(zone)
3804 setup_zone_pageset(zone);
3807 static noinline __init_refok
3808 int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
3811 struct pglist_data *pgdat = zone->zone_pgdat;
3815 * The per-page waitqueue mechanism uses hashed waitqueues
3818 zone->wait_table_hash_nr_entries =
3819 wait_table_hash_nr_entries(zone_size_pages);
3820 zone->wait_table_bits =
3821 wait_table_bits(zone->wait_table_hash_nr_entries);
3822 alloc_size = zone->wait_table_hash_nr_entries
3823 * sizeof(wait_queue_head_t);
3825 if (!slab_is_available()) {
3826 zone->wait_table = (wait_queue_head_t *)
3827 alloc_bootmem_node_nopanic(pgdat, alloc_size);
3830 * This case means that a zone whose size was 0 gets new memory
3831 * via memory hot-add.
3832 * But it may be the case that a new node was hot-added. In
3833 * this case vmalloc() will not be able to use this new node's
3834 * memory - this wait_table must be initialized to use this new
3835 * node itself as well.
3836 * To use this new node's memory, further consideration will be
3839 zone->wait_table = vmalloc(alloc_size);
3841 if (!zone->wait_table)
3844 for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
3845 init_waitqueue_head(zone->wait_table + i);
3850 static int __zone_pcp_update(void *data)
3852 struct zone *zone = data;
3854 unsigned long batch = zone_batchsize(zone), flags;
3856 for_each_possible_cpu(cpu) {
3857 struct per_cpu_pageset *pset;
3858 struct per_cpu_pages *pcp;
3860 pset = per_cpu_ptr(zone->pageset, cpu);
3863 local_irq_save(flags);
3864 free_pcppages_bulk(zone, pcp->count, pcp);
3865 setup_pageset(pset, batch);
3866 local_irq_restore(flags);
3871 void zone_pcp_update(struct zone *zone)
3873 stop_machine(__zone_pcp_update, zone, NULL);
3876 static __meminit void zone_pcp_init(struct zone *zone)
3879 * per cpu subsystem is not up at this point. The following code
3880 * relies on the ability of the linker to provide the
3881 * offset of a (static) per cpu variable into the per cpu area.
3883 zone->pageset = &boot_pageset;
3885 if (zone->present_pages)
3886 printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n",
3887 zone->name, zone->present_pages,
3888 zone_batchsize(zone));
3891 __meminit int init_currently_empty_zone(struct zone *zone,
3892 unsigned long zone_start_pfn,
3894 enum memmap_context context)
3896 struct pglist_data *pgdat = zone->zone_pgdat;
3898 ret = zone_wait_table_init(zone, size);
3901 pgdat->nr_zones = zone_idx(zone) + 1;
3903 zone->zone_start_pfn = zone_start_pfn;
3905 mminit_dprintk(MMINIT_TRACE, "memmap_init",
3906 "Initialising map node %d zone %lu pfns %lu -> %lu\n",
3908 (unsigned long)zone_idx(zone),
3909 zone_start_pfn, (zone_start_pfn + size));
3911 zone_init_free_lists(zone);
3916 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
3917 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
3919 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
3920 * Architectures may implement their own version but if add_active_range()
3921 * was used and there are no special requirements, this is a convenient
3924 int __meminit __early_pfn_to_nid(unsigned long pfn)
3926 unsigned long start_pfn, end_pfn;
3929 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
3930 if (start_pfn <= pfn && pfn < end_pfn)
3932 /* This is a memory hole */
3935 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
3937 int __meminit early_pfn_to_nid(unsigned long pfn)
3941 nid = __early_pfn_to_nid(pfn);
3944 /* just returns 0 */
3948 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
3949 bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
3953 nid = __early_pfn_to_nid(pfn);
3954 if (nid >= 0 && nid != node)
3961 * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
3962 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
3963 * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
3965 * If an architecture guarantees that all ranges registered with
3966 * add_active_ranges() contain no holes and may be freed, this
3967 * this function may be used instead of calling free_bootmem() manually.
3969 void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
3971 unsigned long start_pfn, end_pfn;
3974 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
3975 start_pfn = min(start_pfn, max_low_pfn);
3976 end_pfn = min(end_pfn, max_low_pfn);
3978 if (start_pfn < end_pfn)
3979 free_bootmem_node(NODE_DATA(this_nid),
3980 PFN_PHYS(start_pfn),
3981 (end_pfn - start_pfn) << PAGE_SHIFT);
3986 * sparse_memory_present_with_active_regions - Call memory_present for each active range
3987 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
3989 * If an architecture guarantees that all ranges registered with
3990 * add_active_ranges() contain no holes and may be freed, this
3991 * function may be used instead of calling memory_present() manually.
3993 void __init sparse_memory_present_with_active_regions(int nid)
3995 unsigned long start_pfn, end_pfn;
3998 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
3999 memory_present(this_nid, start_pfn, end_pfn);
4003 * get_pfn_range_for_nid - Return the start and end page frames for a node
4004 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
4005 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
4006 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
4008 * It returns the start and end page frame of a node based on information
4009 * provided by an arch calling add_active_range(). If called for a node
4010 * with no available memory, a warning is printed and the start and end
4013 void __meminit get_pfn_range_for_nid(unsigned int nid,
4014 unsigned long *start_pfn, unsigned long *end_pfn)
4016 unsigned long this_start_pfn, this_end_pfn;
4022 for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
4023 *start_pfn = min(*start_pfn, this_start_pfn);
4024 *end_pfn = max(*end_pfn, this_end_pfn);
4027 if (*start_pfn == -1UL)
4032 * This finds a zone that can be used for ZONE_MOVABLE pages. The
4033 * assumption is made that zones within a node are ordered in monotonic
4034 * increasing memory addresses so that the "highest" populated zone is used
4036 static void __init find_usable_zone_for_movable(void)
4039 for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
4040 if (zone_index == ZONE_MOVABLE)
4043 if (arch_zone_highest_possible_pfn[zone_index] >
4044 arch_zone_lowest_possible_pfn[zone_index])
4048 VM_BUG_ON(zone_index == -1);
4049 movable_zone = zone_index;
4053 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
4054 * because it is sized independent of architecture. Unlike the other zones,
4055 * the starting point for ZONE_MOVABLE is not fixed. It may be different
4056 * in each node depending on the size of each node and how evenly kernelcore
4057 * is distributed. This helper function adjusts the zone ranges
4058 * provided by the architecture for a given node by using the end of the
4059 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
4060 * zones within a node are in order of monotonic increases memory addresses
4062 static void __meminit adjust_zone_range_for_zone_movable(int nid,
4063 unsigned long zone_type,
4064 unsigned long node_start_pfn,
4065 unsigned long node_end_pfn,
4066 unsigned long *zone_start_pfn,
4067 unsigned long *zone_end_pfn)
4069 /* Only adjust if ZONE_MOVABLE is on this node */
4070 if (zone_movable_pfn[nid]) {
4071 /* Size ZONE_MOVABLE */
4072 if (zone_type == ZONE_MOVABLE) {
4073 *zone_start_pfn = zone_movable_pfn[nid];
4074 *zone_end_pfn = min(node_end_pfn,
4075 arch_zone_highest_possible_pfn[movable_zone]);
4077 /* Adjust for ZONE_MOVABLE starting within this range */
4078 } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
4079 *zone_end_pfn > zone_movable_pfn[nid]) {
4080 *zone_end_pfn = zone_movable_pfn[nid];
4082 /* Check if this whole range is within ZONE_MOVABLE */
4083 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
4084 *zone_start_pfn = *zone_end_pfn;
4089 * Return the number of pages a zone spans in a node, including holes
4090 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
4092 static unsigned long __meminit zone_spanned_pages_in_node(int nid,
4093 unsigned long zone_type,
4094 unsigned long *ignored)
4096 unsigned long node_start_pfn, node_end_pfn;
4097 unsigned long zone_start_pfn, zone_end_pfn;
4099 /* Get the start and end of the node and zone */
4100 get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
4101 zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
4102 zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
4103 adjust_zone_range_for_zone_movable(nid, zone_type,
4104 node_start_pfn, node_end_pfn,
4105 &zone_start_pfn, &zone_end_pfn);
4107 /* Check that this node has pages within the zone's required range */
4108 if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
4111 /* Move the zone boundaries inside the node if necessary */
4112 zone_end_pfn = min(zone_end_pfn, node_end_pfn);
4113 zone_start_pfn = max(zone_start_pfn, node_start_pfn);
4115 /* Return the spanned pages */
4116 return zone_end_pfn - zone_start_pfn;
4120 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
4121 * then all holes in the requested range will be accounted for.
4123 unsigned long __meminit __absent_pages_in_range(int nid,
4124 unsigned long range_start_pfn,
4125 unsigned long range_end_pfn)
4127 unsigned long nr_absent = range_end_pfn - range_start_pfn;
4128 unsigned long start_pfn, end_pfn;
4131 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
4132 start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
4133 end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
4134 nr_absent -= end_pfn - start_pfn;
4140 * absent_pages_in_range - Return number of page frames in holes within a range
4141 * @start_pfn: The start PFN to start searching for holes
4142 * @end_pfn: The end PFN to stop searching for holes
4144 * It returns the number of pages frames in memory holes within a range.
4146 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
4147 unsigned long end_pfn)
4149 return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
4152 /* Return the number of page frames in holes in a zone on a node */
4153 static unsigned long __meminit zone_absent_pages_in_node(int nid,
4154 unsigned long zone_type,
4155 unsigned long *ignored)
4157 unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
4158 unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
4159 unsigned long node_start_pfn, node_end_pfn;
4160 unsigned long zone_start_pfn, zone_end_pfn;
4162 get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
4163 zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
4164 zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
4166 adjust_zone_range_for_zone_movable(nid, zone_type,
4167 node_start_pfn, node_end_pfn,
4168 &zone_start_pfn, &zone_end_pfn);
4169 return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
4172 #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4173 static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
4174 unsigned long zone_type,
4175 unsigned long *zones_size)
4177 return zones_size[zone_type];
4180 static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
4181 unsigned long zone_type,
4182 unsigned long *zholes_size)
4187 return zholes_size[zone_type];
4190 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4192 static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
4193 unsigned long *zones_size, unsigned long *zholes_size)
4195 unsigned long realtotalpages, totalpages = 0;
4198 for (i = 0; i < MAX_NR_ZONES; i++)
4199 totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
4201 pgdat->node_spanned_pages = totalpages;
4203 realtotalpages = totalpages;
4204 for (i = 0; i < MAX_NR_ZONES; i++)
4206 zone_absent_pages_in_node(pgdat->node_id, i,
4208 pgdat->node_present_pages = realtotalpages;
4209 printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
4213 #ifndef CONFIG_SPARSEMEM
4215 * Calculate the size of the zone->blockflags rounded to an unsigned long
4216 * Start by making sure zonesize is a multiple of pageblock_order by rounding
4217 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
4218 * round what is now in bits to nearest long in bits, then return it in
4221 static unsigned long __init usemap_size(unsigned long zonesize)
4223 unsigned long usemapsize;
4225 usemapsize = roundup(zonesize, pageblock_nr_pages);
4226 usemapsize = usemapsize >> pageblock_order;
4227 usemapsize *= NR_PAGEBLOCK_BITS;
4228 usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
4230 return usemapsize / 8;
4233 static void __init setup_usemap(struct pglist_data *pgdat,
4234 struct zone *zone, unsigned long zonesize)
4236 unsigned long usemapsize = usemap_size(zonesize);
4237 zone->pageblock_flags = NULL;
4239 zone->pageblock_flags = alloc_bootmem_node_nopanic(pgdat,
4243 static inline void setup_usemap(struct pglist_data *pgdat,
4244 struct zone *zone, unsigned long zonesize) {}
4245 #endif /* CONFIG_SPARSEMEM */
4247 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
4249 /* Return a sensible default order for the pageblock size. */
4250 static inline int pageblock_default_order(void)
4252 if (HPAGE_SHIFT > PAGE_SHIFT)
4253 return HUGETLB_PAGE_ORDER;
4258 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
4259 static inline void __init set_pageblock_order(unsigned int order)
4261 /* Check that pageblock_nr_pages has not already been setup */
4262 if (pageblock_order)
4266 * Assume the largest contiguous order of interest is a huge page.
4267 * This value may be variable depending on boot parameters on IA64
4269 pageblock_order = order;
4271 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4274 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
4275 * and pageblock_default_order() are unused as pageblock_order is set
4276 * at compile-time. See include/linux/pageblock-flags.h for the values of
4277 * pageblock_order based on the kernel config
4279 static inline int pageblock_default_order(unsigned int order)
4283 #define set_pageblock_order(x) do {} while (0)
4285 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4288 * Set up the zone data structures:
4289 * - mark all pages reserved
4290 * - mark all memory queues empty
4291 * - clear the memory bitmaps
4293 static void __paginginit free_area_init_core(struct pglist_data *pgdat,
4294 unsigned long *zones_size, unsigned long *zholes_size)
4297 int nid = pgdat->node_id;
4298 unsigned long zone_start_pfn = pgdat->node_start_pfn;
4301 pgdat_resize_init(pgdat);
4302 pgdat->nr_zones = 0;
4303 init_waitqueue_head(&pgdat->kswapd_wait);
4304 pgdat->kswapd_max_order = 0;
4305 pgdat_page_cgroup_init(pgdat);
4307 for (j = 0; j < MAX_NR_ZONES; j++) {
4308 struct zone *zone = pgdat->node_zones + j;
4309 unsigned long size, realsize, memmap_pages;
4312 size = zone_spanned_pages_in_node(nid, j, zones_size);
4313 realsize = size - zone_absent_pages_in_node(nid, j,
4317 * Adjust realsize so that it accounts for how much memory
4318 * is used by this zone for memmap. This affects the watermark
4319 * and per-cpu initialisations
4322 PAGE_ALIGN(size * sizeof(struct page)) >> PAGE_SHIFT;
4323 if (realsize >= memmap_pages) {
4324 realsize -= memmap_pages;
4327 " %s zone: %lu pages used for memmap\n",
4328 zone_names[j], memmap_pages);
4331 " %s zone: %lu pages exceeds realsize %lu\n",
4332 zone_names[j], memmap_pages, realsize);
4334 /* Account for reserved pages */
4335 if (j == 0 && realsize > dma_reserve) {
4336 realsize -= dma_reserve;
4337 printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
4338 zone_names[0], dma_reserve);
4341 if (!is_highmem_idx(j))
4342 nr_kernel_pages += realsize;
4343 nr_all_pages += realsize;
4345 zone->spanned_pages = size;
4346 zone->present_pages = realsize;
4349 zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
4351 zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
4353 zone->name = zone_names[j];
4354 spin_lock_init(&zone->lock);
4355 spin_lock_init(&zone->lru_lock);
4356 zone_seqlock_init(zone);
4357 zone->zone_pgdat = pgdat;
4359 zone_pcp_init(zone);
4361 INIT_LIST_HEAD(&zone->lruvec.lists[lru]);
4362 zone->reclaim_stat.recent_rotated[0] = 0;
4363 zone->reclaim_stat.recent_rotated[1] = 0;
4364 zone->reclaim_stat.recent_scanned[0] = 0;
4365 zone->reclaim_stat.recent_scanned[1] = 0;
4366 zap_zone_vm_stats(zone);
4371 set_pageblock_order(pageblock_default_order());
4372 setup_usemap(pgdat, zone, size);
4373 ret = init_currently_empty_zone(zone, zone_start_pfn,
4374 size, MEMMAP_EARLY);
4376 memmap_init(size, nid, j, zone_start_pfn);
4377 zone_start_pfn += size;
4381 static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
4383 /* Skip empty nodes */
4384 if (!pgdat->node_spanned_pages)
4387 #ifdef CONFIG_FLAT_NODE_MEM_MAP
4388 /* ia64 gets its own node_mem_map, before this, without bootmem */
4389 if (!pgdat->node_mem_map) {
4390 unsigned long size, start, end;
4394 * The zone's endpoints aren't required to be MAX_ORDER
4395 * aligned but the node_mem_map endpoints must be in order
4396 * for the buddy allocator to function correctly.
4398 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
4399 end = pgdat->node_start_pfn + pgdat->node_spanned_pages;
4400 end = ALIGN(end, MAX_ORDER_NR_PAGES);
4401 size = (end - start) * sizeof(struct page);
4402 map = alloc_remap(pgdat->node_id, size);
4404 map = alloc_bootmem_node_nopanic(pgdat, size);
4405 pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
4407 #ifndef CONFIG_NEED_MULTIPLE_NODES
4409 * With no DISCONTIG, the global mem_map is just set as node 0's
4411 if (pgdat == NODE_DATA(0)) {
4412 mem_map = NODE_DATA(0)->node_mem_map;
4413 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4414 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
4415 mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
4416 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4419 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
4422 void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
4423 unsigned long node_start_pfn, unsigned long *zholes_size)
4425 pg_data_t *pgdat = NODE_DATA(nid);
4427 pgdat->node_id = nid;
4428 pgdat->node_start_pfn = node_start_pfn;
4429 calculate_node_totalpages(pgdat, zones_size, zholes_size);
4431 alloc_node_mem_map(pgdat);
4432 #ifdef CONFIG_FLAT_NODE_MEM_MAP
4433 printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
4434 nid, (unsigned long)pgdat,
4435 (unsigned long)pgdat->node_mem_map);
4438 free_area_init_core(pgdat, zones_size, zholes_size);
4441 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4443 #if MAX_NUMNODES > 1
4445 * Figure out the number of possible node ids.
4447 static void __init setup_nr_node_ids(void)
4450 unsigned int highest = 0;
4452 for_each_node_mask(node, node_possible_map)
4454 nr_node_ids = highest + 1;
4457 static inline void setup_nr_node_ids(void)
4463 * node_map_pfn_alignment - determine the maximum internode alignment
4465 * This function should be called after node map is populated and sorted.
4466 * It calculates the maximum power of two alignment which can distinguish
4469 * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
4470 * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)). If the
4471 * nodes are shifted by 256MiB, 256MiB. Note that if only the last node is
4472 * shifted, 1GiB is enough and this function will indicate so.
4474 * This is used to test whether pfn -> nid mapping of the chosen memory
4475 * model has fine enough granularity to avoid incorrect mapping for the
4476 * populated node map.
4478 * Returns the determined alignment in pfn's. 0 if there is no alignment
4479 * requirement (single node).
4481 unsigned long __init node_map_pfn_alignment(void)
4483 unsigned long accl_mask = 0, last_end = 0;
4484 unsigned long start, end, mask;
4488 for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
4489 if (!start || last_nid < 0 || last_nid == nid) {
4496 * Start with a mask granular enough to pin-point to the
4497 * start pfn and tick off bits one-by-one until it becomes
4498 * too coarse to separate the current node from the last.
4500 mask = ~((1 << __ffs(start)) - 1);
4501 while (mask && last_end <= (start & (mask << 1)))
4504 /* accumulate all internode masks */
4508 /* convert mask to number of pages */
4509 return ~accl_mask + 1;
4512 /* Find the lowest pfn for a node */
4513 static unsigned long __init find_min_pfn_for_node(int nid)
4515 unsigned long min_pfn = ULONG_MAX;
4516 unsigned long start_pfn;
4519 for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
4520 min_pfn = min(min_pfn, start_pfn);
4522 if (min_pfn == ULONG_MAX) {
4524 "Could not find start_pfn for node %d\n", nid);
4532 * find_min_pfn_with_active_regions - Find the minimum PFN registered
4534 * It returns the minimum PFN based on information provided via
4535 * add_active_range().
4537 unsigned long __init find_min_pfn_with_active_regions(void)
4539 return find_min_pfn_for_node(MAX_NUMNODES);
4543 * early_calculate_totalpages()
4544 * Sum pages in active regions for movable zone.
4545 * Populate N_HIGH_MEMORY for calculating usable_nodes.
4547 static unsigned long __init early_calculate_totalpages(void)
4549 unsigned long totalpages = 0;
4550 unsigned long start_pfn, end_pfn;
4553 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
4554 unsigned long pages = end_pfn - start_pfn;
4556 totalpages += pages;
4558 node_set_state(nid, N_HIGH_MEMORY);
4564 * Find the PFN the Movable zone begins in each node. Kernel memory
4565 * is spread evenly between nodes as long as the nodes have enough
4566 * memory. When they don't, some nodes will have more kernelcore than
4569 static void __init find_zone_movable_pfns_for_nodes(void)
4572 unsigned long usable_startpfn;
4573 unsigned long kernelcore_node, kernelcore_remaining;
4574 /* save the state before borrow the nodemask */
4575 nodemask_t saved_node_state = node_states[N_HIGH_MEMORY];
4576 unsigned long totalpages = early_calculate_totalpages();
4577 int usable_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
4580 * If movablecore was specified, calculate what size of
4581 * kernelcore that corresponds so that memory usable for
4582 * any allocation type is evenly spread. If both kernelcore
4583 * and movablecore are specified, then the value of kernelcore
4584 * will be used for required_kernelcore if it's greater than
4585 * what movablecore would have allowed.
4587 if (required_movablecore) {
4588 unsigned long corepages;
4591 * Round-up so that ZONE_MOVABLE is at least as large as what
4592 * was requested by the user
4594 required_movablecore =
4595 roundup(required_movablecore, MAX_ORDER_NR_PAGES);
4596 corepages = totalpages - required_movablecore;
4598 required_kernelcore = max(required_kernelcore, corepages);
4601 /* If kernelcore was not specified, there is no ZONE_MOVABLE */
4602 if (!required_kernelcore)
4605 /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
4606 find_usable_zone_for_movable();
4607 usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
4610 /* Spread kernelcore memory as evenly as possible throughout nodes */
4611 kernelcore_node = required_kernelcore / usable_nodes;
4612 for_each_node_state(nid, N_HIGH_MEMORY) {
4613 unsigned long start_pfn, end_pfn;
4616 * Recalculate kernelcore_node if the division per node
4617 * now exceeds what is necessary to satisfy the requested
4618 * amount of memory for the kernel
4620 if (required_kernelcore < kernelcore_node)
4621 kernelcore_node = required_kernelcore / usable_nodes;
4624 * As the map is walked, we track how much memory is usable
4625 * by the kernel using kernelcore_remaining. When it is
4626 * 0, the rest of the node is usable by ZONE_MOVABLE
4628 kernelcore_remaining = kernelcore_node;
4630 /* Go through each range of PFNs within this node */
4631 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
4632 unsigned long size_pages;
4634 start_pfn = max(start_pfn, zone_movable_pfn[nid]);
4635 if (start_pfn >= end_pfn)
4638 /* Account for what is only usable for kernelcore */
4639 if (start_pfn < usable_startpfn) {
4640 unsigned long kernel_pages;
4641 kernel_pages = min(end_pfn, usable_startpfn)
4644 kernelcore_remaining -= min(kernel_pages,
4645 kernelcore_remaining);
4646 required_kernelcore -= min(kernel_pages,
4647 required_kernelcore);
4649 /* Continue if range is now fully accounted */
4650 if (end_pfn <= usable_startpfn) {
4653 * Push zone_movable_pfn to the end so
4654 * that if we have to rebalance
4655 * kernelcore across nodes, we will
4656 * not double account here
4658 zone_movable_pfn[nid] = end_pfn;
4661 start_pfn = usable_startpfn;
4665 * The usable PFN range for ZONE_MOVABLE is from
4666 * start_pfn->end_pfn. Calculate size_pages as the
4667 * number of pages used as kernelcore
4669 size_pages = end_pfn - start_pfn;
4670 if (size_pages > kernelcore_remaining)
4671 size_pages = kernelcore_remaining;
4672 zone_movable_pfn[nid] = start_pfn + size_pages;
4675 * Some kernelcore has been met, update counts and
4676 * break if the kernelcore for this node has been
4679 required_kernelcore -= min(required_kernelcore,
4681 kernelcore_remaining -= size_pages;
4682 if (!kernelcore_remaining)
4688 * If there is still required_kernelcore, we do another pass with one
4689 * less node in the count. This will push zone_movable_pfn[nid] further
4690 * along on the nodes that still have memory until kernelcore is
4694 if (usable_nodes && required_kernelcore > usable_nodes)
4697 /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
4698 for (nid = 0; nid < MAX_NUMNODES; nid++)
4699 zone_movable_pfn[nid] =
4700 roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
4703 /* restore the node_state */
4704 node_states[N_HIGH_MEMORY] = saved_node_state;
4707 /* Any regular memory on that node ? */
4708 static void check_for_regular_memory(pg_data_t *pgdat)
4710 #ifdef CONFIG_HIGHMEM
4711 enum zone_type zone_type;
4713 for (zone_type = 0; zone_type <= ZONE_NORMAL; zone_type++) {
4714 struct zone *zone = &pgdat->node_zones[zone_type];
4715 if (zone->present_pages) {
4716 node_set_state(zone_to_nid(zone), N_NORMAL_MEMORY);
4724 * free_area_init_nodes - Initialise all pg_data_t and zone data
4725 * @max_zone_pfn: an array of max PFNs for each zone
4727 * This will call free_area_init_node() for each active node in the system.
4728 * Using the page ranges provided by add_active_range(), the size of each
4729 * zone in each node and their holes is calculated. If the maximum PFN
4730 * between two adjacent zones match, it is assumed that the zone is empty.
4731 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
4732 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
4733 * starts where the previous one ended. For example, ZONE_DMA32 starts
4734 * at arch_max_dma_pfn.
4736 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
4738 unsigned long start_pfn, end_pfn;
4741 /* Record where the zone boundaries are */
4742 memset(arch_zone_lowest_possible_pfn, 0,
4743 sizeof(arch_zone_lowest_possible_pfn));
4744 memset(arch_zone_highest_possible_pfn, 0,
4745 sizeof(arch_zone_highest_possible_pfn));
4746 arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
4747 arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
4748 for (i = 1; i < MAX_NR_ZONES; i++) {
4749 if (i == ZONE_MOVABLE)
4751 arch_zone_lowest_possible_pfn[i] =
4752 arch_zone_highest_possible_pfn[i-1];
4753 arch_zone_highest_possible_pfn[i] =
4754 max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
4756 arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
4757 arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
4759 /* Find the PFNs that ZONE_MOVABLE begins at in each node */
4760 memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
4761 find_zone_movable_pfns_for_nodes();
4763 /* Print out the zone ranges */
4764 printk("Zone PFN ranges:\n");
4765 for (i = 0; i < MAX_NR_ZONES; i++) {
4766 if (i == ZONE_MOVABLE)
4768 printk(" %-8s ", zone_names[i]);
4769 if (arch_zone_lowest_possible_pfn[i] ==
4770 arch_zone_highest_possible_pfn[i])
4773 printk("%0#10lx -> %0#10lx\n",
4774 arch_zone_lowest_possible_pfn[i],
4775 arch_zone_highest_possible_pfn[i]);
4778 /* Print out the PFNs ZONE_MOVABLE begins at in each node */
4779 printk("Movable zone start PFN for each node\n");
4780 for (i = 0; i < MAX_NUMNODES; i++) {
4781 if (zone_movable_pfn[i])
4782 printk(" Node %d: %lu\n", i, zone_movable_pfn[i]);
4785 /* Print out the early_node_map[] */
4786 printk("Early memory PFN ranges\n");
4787 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
4788 printk(" %3d: %0#10lx -> %0#10lx\n", nid, start_pfn, end_pfn);
4790 /* Initialise every node */
4791 mminit_verify_pageflags_layout();
4792 setup_nr_node_ids();
4793 for_each_online_node(nid) {
4794 pg_data_t *pgdat = NODE_DATA(nid);
4795 free_area_init_node(nid, NULL,
4796 find_min_pfn_for_node(nid), NULL);
4798 /* Any memory on that node */
4799 if (pgdat->node_present_pages)
4800 node_set_state(nid, N_HIGH_MEMORY);
4801 check_for_regular_memory(pgdat);
4805 static int __init cmdline_parse_core(char *p, unsigned long *core)
4807 unsigned long long coremem;
4811 coremem = memparse(p, &p);
4812 *core = coremem >> PAGE_SHIFT;
4814 /* Paranoid check that UL is enough for the coremem value */
4815 WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
4821 * kernelcore=size sets the amount of memory for use for allocations that
4822 * cannot be reclaimed or migrated.
4824 static int __init cmdline_parse_kernelcore(char *p)
4826 return cmdline_parse_core(p, &required_kernelcore);
4830 * movablecore=size sets the amount of memory for use for allocations that
4831 * can be reclaimed or migrated.
4833 static int __init cmdline_parse_movablecore(char *p)
4835 return cmdline_parse_core(p, &required_movablecore);
4838 early_param("kernelcore", cmdline_parse_kernelcore);
4839 early_param("movablecore", cmdline_parse_movablecore);
4841 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4844 * set_dma_reserve - set the specified number of pages reserved in the first zone
4845 * @new_dma_reserve: The number of pages to mark reserved
4847 * The per-cpu batchsize and zone watermarks are determined by present_pages.
4848 * In the DMA zone, a significant percentage may be consumed by kernel image
4849 * and other unfreeable allocations which can skew the watermarks badly. This
4850 * function may optionally be used to account for unfreeable pages in the
4851 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
4852 * smaller per-cpu batchsize.
4854 void __init set_dma_reserve(unsigned long new_dma_reserve)
4856 dma_reserve = new_dma_reserve;
4859 void __init free_area_init(unsigned long *zones_size)
4861 free_area_init_node(0, zones_size,
4862 __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
4865 static int page_alloc_cpu_notify(struct notifier_block *self,
4866 unsigned long action, void *hcpu)
4868 int cpu = (unsigned long)hcpu;
4870 if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
4871 lru_add_drain_cpu(cpu);
4875 * Spill the event counters of the dead processor
4876 * into the current processors event counters.
4877 * This artificially elevates the count of the current
4880 vm_events_fold_cpu(cpu);
4883 * Zero the differential counters of the dead processor
4884 * so that the vm statistics are consistent.
4886 * This is only okay since the processor is dead and cannot
4887 * race with what we are doing.
4889 refresh_cpu_vm_stats(cpu);
4894 void __init page_alloc_init(void)
4896 hotcpu_notifier(page_alloc_cpu_notify, 0);
4900 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
4901 * or min_free_kbytes changes.
4903 static void calculate_totalreserve_pages(void)
4905 struct pglist_data *pgdat;
4906 unsigned long reserve_pages = 0;
4907 enum zone_type i, j;
4909 for_each_online_pgdat(pgdat) {
4910 for (i = 0; i < MAX_NR_ZONES; i++) {
4911 struct zone *zone = pgdat->node_zones + i;
4912 unsigned long max = 0;
4914 /* Find valid and maximum lowmem_reserve in the zone */
4915 for (j = i; j < MAX_NR_ZONES; j++) {
4916 if (zone->lowmem_reserve[j] > max)
4917 max = zone->lowmem_reserve[j];
4920 /* we treat the high watermark as reserved pages. */
4921 max += high_wmark_pages(zone);
4923 if (max > zone->present_pages)
4924 max = zone->present_pages;
4925 reserve_pages += max;
4927 * Lowmem reserves are not available to
4928 * GFP_HIGHUSER page cache allocations and
4929 * kswapd tries to balance zones to their high
4930 * watermark. As a result, neither should be
4931 * regarded as dirtyable memory, to prevent a
4932 * situation where reclaim has to clean pages
4933 * in order to balance the zones.
4935 zone->dirty_balance_reserve = max;
4938 dirty_balance_reserve = reserve_pages;
4939 totalreserve_pages = reserve_pages;
4943 * setup_per_zone_lowmem_reserve - called whenever
4944 * sysctl_lower_zone_reserve_ratio changes. Ensures that each zone
4945 * has a correct pages reserved value, so an adequate number of
4946 * pages are left in the zone after a successful __alloc_pages().
4948 static void setup_per_zone_lowmem_reserve(void)
4950 struct pglist_data *pgdat;
4951 enum zone_type j, idx;
4953 for_each_online_pgdat(pgdat) {
4954 for (j = 0; j < MAX_NR_ZONES; j++) {
4955 struct zone *zone = pgdat->node_zones + j;
4956 unsigned long present_pages = zone->present_pages;
4958 zone->lowmem_reserve[j] = 0;
4962 struct zone *lower_zone;
4966 if (sysctl_lowmem_reserve_ratio[idx] < 1)
4967 sysctl_lowmem_reserve_ratio[idx] = 1;
4969 lower_zone = pgdat->node_zones + idx;
4970 lower_zone->lowmem_reserve[j] = present_pages /
4971 sysctl_lowmem_reserve_ratio[idx];
4972 present_pages += lower_zone->present_pages;
4977 /* update totalreserve_pages */
4978 calculate_totalreserve_pages();
4982 * setup_per_zone_wmarks - called when min_free_kbytes changes
4983 * or when memory is hot-{added|removed}
4985 * Ensures that the watermark[min,low,high] values for each zone are set
4986 * correctly with respect to min_free_kbytes.
4988 void setup_per_zone_wmarks(void)
4990 unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
4991 unsigned long lowmem_pages = 0;
4993 unsigned long flags;
4995 /* Calculate total number of !ZONE_HIGHMEM pages */
4996 for_each_zone(zone) {
4997 if (!is_highmem(zone))
4998 lowmem_pages += zone->present_pages;
5001 for_each_zone(zone) {
5004 spin_lock_irqsave(&zone->lock, flags);
5005 tmp = (u64)pages_min * zone->present_pages;
5006 do_div(tmp, lowmem_pages);
5007 if (is_highmem(zone)) {
5009 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
5010 * need highmem pages, so cap pages_min to a small
5013 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
5014 * deltas controls asynch page reclaim, and so should
5015 * not be capped for highmem.
5019 min_pages = zone->present_pages / 1024;
5020 if (min_pages < SWAP_CLUSTER_MAX)
5021 min_pages = SWAP_CLUSTER_MAX;
5022 if (min_pages > 128)
5024 zone->watermark[WMARK_MIN] = min_pages;
5027 * If it's a lowmem zone, reserve a number of pages
5028 * proportionate to the zone's size.
5030 zone->watermark[WMARK_MIN] = tmp;
5033 zone->watermark[WMARK_LOW] = min_wmark_pages(zone) + (tmp >> 2);
5034 zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
5035 setup_zone_migrate_reserve(zone);
5036 spin_unlock_irqrestore(&zone->lock, flags);
5039 /* update totalreserve_pages */
5040 calculate_totalreserve_pages();
5044 * The inactive anon list should be small enough that the VM never has to
5045 * do too much work, but large enough that each inactive page has a chance
5046 * to be referenced again before it is swapped out.
5048 * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
5049 * INACTIVE_ANON pages on this zone's LRU, maintained by the
5050 * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
5051 * the anonymous pages are kept on the inactive list.
5054 * memory ratio inactive anon
5055 * -------------------------------------
5064 static void __meminit calculate_zone_inactive_ratio(struct zone *zone)
5066 unsigned int gb, ratio;
5068 /* Zone size in gigabytes */
5069 gb = zone->present_pages >> (30 - PAGE_SHIFT);
5071 ratio = int_sqrt(10 * gb);
5075 zone->inactive_ratio = ratio;
5078 static void __meminit setup_per_zone_inactive_ratio(void)
5083 calculate_zone_inactive_ratio(zone);
5087 * Initialise min_free_kbytes.
5089 * For small machines we want it small (128k min). For large machines
5090 * we want it large (64MB max). But it is not linear, because network
5091 * bandwidth does not increase linearly with machine size. We use
5093 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
5094 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
5110 int __meminit init_per_zone_wmark_min(void)
5112 unsigned long lowmem_kbytes;
5114 lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
5116 min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
5117 if (min_free_kbytes < 128)
5118 min_free_kbytes = 128;
5119 if (min_free_kbytes > 65536)
5120 min_free_kbytes = 65536;
5121 setup_per_zone_wmarks();
5122 refresh_zone_stat_thresholds();
5123 setup_per_zone_lowmem_reserve();
5124 setup_per_zone_inactive_ratio();
5127 module_init(init_per_zone_wmark_min)
5130 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
5131 * that we can call two helper functions whenever min_free_kbytes
5134 int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
5135 void __user *buffer, size_t *length, loff_t *ppos)
5137 proc_dointvec(table, write, buffer, length, ppos);
5139 setup_per_zone_wmarks();
5144 int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
5145 void __user *buffer, size_t *length, loff_t *ppos)
5150 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5155 zone->min_unmapped_pages = (zone->present_pages *
5156 sysctl_min_unmapped_ratio) / 100;
5160 int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
5161 void __user *buffer, size_t *length, loff_t *ppos)
5166 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5171 zone->min_slab_pages = (zone->present_pages *
5172 sysctl_min_slab_ratio) / 100;
5178 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
5179 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
5180 * whenever sysctl_lowmem_reserve_ratio changes.
5182 * The reserve ratio obviously has absolutely no relation with the
5183 * minimum watermarks. The lowmem reserve ratio can only make sense
5184 * if in function of the boot time zone sizes.
5186 int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
5187 void __user *buffer, size_t *length, loff_t *ppos)
5189 proc_dointvec_minmax(table, write, buffer, length, ppos);
5190 setup_per_zone_lowmem_reserve();
5195 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
5196 * cpu. It is the fraction of total pages in each zone that a hot per cpu pagelist
5197 * can have before it gets flushed back to buddy allocator.
5200 int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
5201 void __user *buffer, size_t *length, loff_t *ppos)
5207 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
5208 if (!write || (ret < 0))
5210 for_each_populated_zone(zone) {
5211 for_each_possible_cpu(cpu) {
5213 high = zone->present_pages / percpu_pagelist_fraction;
5214 setup_pagelist_highmark(
5215 per_cpu_ptr(zone->pageset, cpu), high);
5221 int hashdist = HASHDIST_DEFAULT;
5224 static int __init set_hashdist(char *str)
5228 hashdist = simple_strtoul(str, &str, 0);
5231 __setup("hashdist=", set_hashdist);
5235 * allocate a large system hash table from bootmem
5236 * - it is assumed that the hash table must contain an exact power-of-2
5237 * quantity of entries
5238 * - limit is the number of hash buckets, not the total allocation size
5240 void *__init alloc_large_system_hash(const char *tablename,
5241 unsigned long bucketsize,
5242 unsigned long numentries,
5245 unsigned int *_hash_shift,
5246 unsigned int *_hash_mask,
5247 unsigned long limit)
5249 unsigned long long max = limit;
5250 unsigned long log2qty, size;
5253 /* allow the kernel cmdline to have a say */
5255 /* round applicable memory size up to nearest megabyte */
5256 numentries = nr_kernel_pages;
5257 numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
5258 numentries >>= 20 - PAGE_SHIFT;
5259 numentries <<= 20 - PAGE_SHIFT;
5261 /* limit to 1 bucket per 2^scale bytes of low memory */
5262 if (scale > PAGE_SHIFT)
5263 numentries >>= (scale - PAGE_SHIFT);
5265 numentries <<= (PAGE_SHIFT - scale);
5267 /* Make sure we've got at least a 0-order allocation.. */
5268 if (unlikely(flags & HASH_SMALL)) {
5269 /* Makes no sense without HASH_EARLY */
5270 WARN_ON(!(flags & HASH_EARLY));
5271 if (!(numentries >> *_hash_shift)) {
5272 numentries = 1UL << *_hash_shift;
5273 BUG_ON(!numentries);
5275 } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
5276 numentries = PAGE_SIZE / bucketsize;
5278 numentries = roundup_pow_of_two(numentries);
5280 /* limit allocation size to 1/16 total memory by default */
5282 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
5283 do_div(max, bucketsize);
5285 max = min(max, 0x80000000ULL);
5287 if (numentries > max)
5290 log2qty = ilog2(numentries);
5293 size = bucketsize << log2qty;
5294 if (flags & HASH_EARLY)
5295 table = alloc_bootmem_nopanic(size);
5297 table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
5300 * If bucketsize is not a power-of-two, we may free
5301 * some pages at the end of hash table which
5302 * alloc_pages_exact() automatically does
5304 if (get_order(size) < MAX_ORDER) {
5305 table = alloc_pages_exact(size, GFP_ATOMIC);
5306 kmemleak_alloc(table, size, 1, GFP_ATOMIC);
5309 } while (!table && size > PAGE_SIZE && --log2qty);
5312 panic("Failed to allocate %s hash table\n", tablename);
5314 printk(KERN_INFO "%s hash table entries: %ld (order: %d, %lu bytes)\n",
5317 ilog2(size) - PAGE_SHIFT,
5321 *_hash_shift = log2qty;
5323 *_hash_mask = (1 << log2qty) - 1;
5328 /* Return a pointer to the bitmap storing bits affecting a block of pages */
5329 static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
5332 #ifdef CONFIG_SPARSEMEM
5333 return __pfn_to_section(pfn)->pageblock_flags;
5335 return zone->pageblock_flags;
5336 #endif /* CONFIG_SPARSEMEM */
5339 static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
5341 #ifdef CONFIG_SPARSEMEM
5342 pfn &= (PAGES_PER_SECTION-1);
5343 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5345 pfn = pfn - zone->zone_start_pfn;
5346 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5347 #endif /* CONFIG_SPARSEMEM */
5351 * get_pageblock_flags_group - Return the requested group of flags for the pageblock_nr_pages block of pages
5352 * @page: The page within the block of interest
5353 * @start_bitidx: The first bit of interest to retrieve
5354 * @end_bitidx: The last bit of interest
5355 * returns pageblock_bits flags
5357 unsigned long get_pageblock_flags_group(struct page *page,
5358 int start_bitidx, int end_bitidx)
5361 unsigned long *bitmap;
5362 unsigned long pfn, bitidx;
5363 unsigned long flags = 0;
5364 unsigned long value = 1;
5366 zone = page_zone(page);
5367 pfn = page_to_pfn(page);
5368 bitmap = get_pageblock_bitmap(zone, pfn);
5369 bitidx = pfn_to_bitidx(zone, pfn);
5371 for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5372 if (test_bit(bitidx + start_bitidx, bitmap))
5379 * set_pageblock_flags_group - Set the requested group of flags for a pageblock_nr_pages block of pages
5380 * @page: The page within the block of interest
5381 * @start_bitidx: The first bit of interest
5382 * @end_bitidx: The last bit of interest
5383 * @flags: The flags to set
5385 void set_pageblock_flags_group(struct page *page, unsigned long flags,
5386 int start_bitidx, int end_bitidx)
5389 unsigned long *bitmap;
5390 unsigned long pfn, bitidx;
5391 unsigned long value = 1;
5393 zone = page_zone(page);
5394 pfn = page_to_pfn(page);
5395 bitmap = get_pageblock_bitmap(zone, pfn);
5396 bitidx = pfn_to_bitidx(zone, pfn);
5397 VM_BUG_ON(pfn < zone->zone_start_pfn);
5398 VM_BUG_ON(pfn >= zone->zone_start_pfn + zone->spanned_pages);
5400 for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5402 __set_bit(bitidx + start_bitidx, bitmap);
5404 __clear_bit(bitidx + start_bitidx, bitmap);
5408 * This is designed as sub function...plz see page_isolation.c also.
5409 * set/clear page block's type to be ISOLATE.
5410 * page allocater never alloc memory from ISOLATE block.
5414 __count_immobile_pages(struct zone *zone, struct page *page, int count)
5416 unsigned long pfn, iter, found;
5418 * For avoiding noise data, lru_add_drain_all() should be called
5419 * If ZONE_MOVABLE, the zone never contains immobile pages
5421 if (zone_idx(zone) == ZONE_MOVABLE)
5424 if (get_pageblock_migratetype(page) == MIGRATE_MOVABLE)
5427 pfn = page_to_pfn(page);
5428 for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
5429 unsigned long check = pfn + iter;
5431 if (!pfn_valid_within(check))
5434 page = pfn_to_page(check);
5435 if (!page_count(page)) {
5436 if (PageBuddy(page))
5437 iter += (1 << page_order(page)) - 1;
5443 * If there are RECLAIMABLE pages, we need to check it.
5444 * But now, memory offline itself doesn't call shrink_slab()
5445 * and it still to be fixed.
5448 * If the page is not RAM, page_count()should be 0.
5449 * we don't need more check. This is an _used_ not-movable page.
5451 * The problematic thing here is PG_reserved pages. PG_reserved
5452 * is set to both of a memory hole page and a _used_ kernel
5461 bool is_pageblock_removable_nolock(struct page *page)
5467 * We have to be careful here because we are iterating over memory
5468 * sections which are not zone aware so we might end up outside of
5469 * the zone but still within the section.
5470 * We have to take care about the node as well. If the node is offline
5471 * its NODE_DATA will be NULL - see page_zone.
5473 if (!node_online(page_to_nid(page)))
5476 zone = page_zone(page);
5477 pfn = page_to_pfn(page);
5478 if (zone->zone_start_pfn > pfn ||
5479 zone->zone_start_pfn + zone->spanned_pages <= pfn)
5482 return __count_immobile_pages(zone, page, 0);
5485 int set_migratetype_isolate(struct page *page)
5488 unsigned long flags, pfn;
5489 struct memory_isolate_notify arg;
5493 zone = page_zone(page);
5495 spin_lock_irqsave(&zone->lock, flags);
5497 pfn = page_to_pfn(page);
5498 arg.start_pfn = pfn;
5499 arg.nr_pages = pageblock_nr_pages;
5500 arg.pages_found = 0;
5503 * It may be possible to isolate a pageblock even if the
5504 * migratetype is not MIGRATE_MOVABLE. The memory isolation
5505 * notifier chain is used by balloon drivers to return the
5506 * number of pages in a range that are held by the balloon
5507 * driver to shrink memory. If all the pages are accounted for
5508 * by balloons, are free, or on the LRU, isolation can continue.
5509 * Later, for example, when memory hotplug notifier runs, these
5510 * pages reported as "can be isolated" should be isolated(freed)
5511 * by the balloon driver through the memory notifier chain.
5513 notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
5514 notifier_ret = notifier_to_errno(notifier_ret);
5518 * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
5519 * We just check MOVABLE pages.
5521 if (__count_immobile_pages(zone, page, arg.pages_found))
5525 * immobile means "not-on-lru" paes. If immobile is larger than
5526 * removable-by-driver pages reported by notifier, we'll fail.
5531 set_pageblock_migratetype(page, MIGRATE_ISOLATE);
5532 move_freepages_block(zone, page, MIGRATE_ISOLATE);
5535 spin_unlock_irqrestore(&zone->lock, flags);
5541 void unset_migratetype_isolate(struct page *page)
5544 unsigned long flags;
5545 zone = page_zone(page);
5546 spin_lock_irqsave(&zone->lock, flags);
5547 if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
5549 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5550 move_freepages_block(zone, page, MIGRATE_MOVABLE);
5552 spin_unlock_irqrestore(&zone->lock, flags);
5557 static unsigned long pfn_max_align_down(unsigned long pfn)
5559 return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
5560 pageblock_nr_pages) - 1);
5563 static unsigned long pfn_max_align_up(unsigned long pfn)
5565 return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
5566 pageblock_nr_pages));
5569 static struct page *
5570 __alloc_contig_migrate_alloc(struct page *page, unsigned long private,
5573 return alloc_page(GFP_HIGHUSER_MOVABLE);
5576 /* [start, end) must belong to a single zone. */
5577 static int __alloc_contig_migrate_range(unsigned long start, unsigned long end)
5579 /* This function is based on compact_zone() from compaction.c. */
5581 unsigned long pfn = start;
5582 unsigned int tries = 0;
5585 struct compact_control cc = {
5586 .nr_migratepages = 0,
5588 .zone = page_zone(pfn_to_page(start)),
5591 INIT_LIST_HEAD(&cc.migratepages);
5593 migrate_prep_local();
5595 while (pfn < end || !list_empty(&cc.migratepages)) {
5596 if (fatal_signal_pending(current)) {
5601 if (list_empty(&cc.migratepages)) {
5602 cc.nr_migratepages = 0;
5603 pfn = isolate_migratepages_range(cc.zone, &cc,
5610 } else if (++tries == 5) {
5611 ret = ret < 0 ? ret : -EBUSY;
5615 ret = migrate_pages(&cc.migratepages,
5616 __alloc_contig_migrate_alloc,
5620 putback_lru_pages(&cc.migratepages);
5621 return ret > 0 ? 0 : ret;
5625 * alloc_contig_range() -- tries to allocate given range of pages
5626 * @start: start PFN to allocate
5627 * @end: one-past-the-last PFN to allocate
5629 * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
5630 * aligned, however it's the caller's responsibility to guarantee that
5631 * we are the only thread that changes migrate type of pageblocks the
5634 * The PFN range must belong to a single zone.
5636 * Returns zero on success or negative error code. On success all
5637 * pages which PFN is in [start, end) are allocated for the caller and
5638 * need to be freed with free_contig_range().
5640 int alloc_contig_range(unsigned long start, unsigned long end)
5642 struct zone *zone = page_zone(pfn_to_page(start));
5643 unsigned long outer_start, outer_end;
5647 * What we do here is we mark all pageblocks in range as
5648 * MIGRATE_ISOLATE. Because pageblock and max order pages may
5649 * have different sizes, and due to the way page allocator
5650 * work, we align the range to biggest of the two pages so
5651 * that page allocator won't try to merge buddies from
5652 * different pageblocks and change MIGRATE_ISOLATE to some
5653 * other migration type.
5655 * Once the pageblocks are marked as MIGRATE_ISOLATE, we
5656 * migrate the pages from an unaligned range (ie. pages that
5657 * we are interested in). This will put all the pages in
5658 * range back to page allocator as MIGRATE_ISOLATE.
5660 * When this is done, we take the pages in range from page
5661 * allocator removing them from the buddy system. This way
5662 * page allocator will never consider using them.
5664 * This lets us mark the pageblocks back as
5665 * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
5666 * aligned range but not in the unaligned, original range are
5667 * put back to page allocator so that buddy can use them.
5670 ret = start_isolate_page_range(pfn_max_align_down(start),
5671 pfn_max_align_up(end));
5675 ret = __alloc_contig_migrate_range(start, end);
5680 * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
5681 * aligned blocks that are marked as MIGRATE_ISOLATE. What's
5682 * more, all pages in [start, end) are free in page allocator.
5683 * What we are going to do is to allocate all pages from
5684 * [start, end) (that is remove them from page allocator).
5686 * The only problem is that pages at the beginning and at the
5687 * end of interesting range may be not aligned with pages that
5688 * page allocator holds, ie. they can be part of higher order
5689 * pages. Because of this, we reserve the bigger range and
5690 * once this is done free the pages we are not interested in.
5692 * We don't have to hold zone->lock here because the pages are
5693 * isolated thus they won't get removed from buddy.
5696 lru_add_drain_all();
5700 outer_start = start;
5701 while (!PageBuddy(pfn_to_page(outer_start))) {
5702 if (++order >= MAX_ORDER) {
5706 outer_start &= ~0UL << order;
5709 /* Make sure the range is really isolated. */
5710 if (test_pages_isolated(outer_start, end)) {
5711 pr_warn("alloc_contig_range test_pages_isolated(%lx, %lx) failed\n",
5717 outer_end = isolate_freepages_range(outer_start, end);
5723 /* Free head and tail (if any) */
5724 if (start != outer_start)
5725 free_contig_range(outer_start, start - outer_start);
5726 if (end != outer_end)
5727 free_contig_range(end, outer_end - end);
5730 undo_isolate_page_range(pfn_max_align_down(start),
5731 pfn_max_align_up(end));
5735 void free_contig_range(unsigned long pfn, unsigned nr_pages)
5737 for (; nr_pages--; ++pfn)
5738 __free_page(pfn_to_page(pfn));
5742 #ifdef CONFIG_MEMORY_HOTREMOVE
5744 * All pages in the range must be isolated before calling this.
5747 __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
5753 unsigned long flags;
5754 /* find the first valid pfn */
5755 for (pfn = start_pfn; pfn < end_pfn; pfn++)
5760 zone = page_zone(pfn_to_page(pfn));
5761 spin_lock_irqsave(&zone->lock, flags);
5763 while (pfn < end_pfn) {
5764 if (!pfn_valid(pfn)) {
5768 page = pfn_to_page(pfn);
5769 BUG_ON(page_count(page));
5770 BUG_ON(!PageBuddy(page));
5771 order = page_order(page);
5772 #ifdef CONFIG_DEBUG_VM
5773 printk(KERN_INFO "remove from free list %lx %d %lx\n",
5774 pfn, 1 << order, end_pfn);
5776 list_del(&page->lru);
5777 rmv_page_order(page);
5778 zone->free_area[order].nr_free--;
5779 __mod_zone_page_state(zone, NR_FREE_PAGES,
5781 for (i = 0; i < (1 << order); i++)
5782 SetPageReserved((page+i));
5783 pfn += (1 << order);
5785 spin_unlock_irqrestore(&zone->lock, flags);
5789 #ifdef CONFIG_MEMORY_FAILURE
5790 bool is_free_buddy_page(struct page *page)
5792 struct zone *zone = page_zone(page);
5793 unsigned long pfn = page_to_pfn(page);
5794 unsigned long flags;
5797 spin_lock_irqsave(&zone->lock, flags);
5798 for (order = 0; order < MAX_ORDER; order++) {
5799 struct page *page_head = page - (pfn & ((1 << order) - 1));
5801 if (PageBuddy(page_head) && page_order(page_head) >= order)
5804 spin_unlock_irqrestore(&zone->lock, flags);
5806 return order < MAX_ORDER;
5810 static struct trace_print_flags pageflag_names[] = {
5811 {1UL << PG_locked, "locked" },
5812 {1UL << PG_error, "error" },
5813 {1UL << PG_referenced, "referenced" },
5814 {1UL << PG_uptodate, "uptodate" },
5815 {1UL << PG_dirty, "dirty" },
5816 {1UL << PG_lru, "lru" },
5817 {1UL << PG_active, "active" },
5818 {1UL << PG_slab, "slab" },
5819 {1UL << PG_owner_priv_1, "owner_priv_1" },
5820 {1UL << PG_arch_1, "arch_1" },
5821 {1UL << PG_reserved, "reserved" },
5822 {1UL << PG_private, "private" },
5823 {1UL << PG_private_2, "private_2" },
5824 {1UL << PG_writeback, "writeback" },
5825 #ifdef CONFIG_PAGEFLAGS_EXTENDED
5826 {1UL << PG_head, "head" },
5827 {1UL << PG_tail, "tail" },
5829 {1UL << PG_compound, "compound" },
5831 {1UL << PG_swapcache, "swapcache" },
5832 {1UL << PG_mappedtodisk, "mappedtodisk" },
5833 {1UL << PG_reclaim, "reclaim" },
5834 {1UL << PG_swapbacked, "swapbacked" },
5835 {1UL << PG_unevictable, "unevictable" },
5837 {1UL << PG_mlocked, "mlocked" },
5839 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
5840 {1UL << PG_uncached, "uncached" },
5842 #ifdef CONFIG_MEMORY_FAILURE
5843 {1UL << PG_hwpoison, "hwpoison" },
5848 static void dump_page_flags(unsigned long flags)
5850 const char *delim = "";
5854 printk(KERN_ALERT "page flags: %#lx(", flags);
5856 /* remove zone id */
5857 flags &= (1UL << NR_PAGEFLAGS) - 1;
5859 for (i = 0; pageflag_names[i].name && flags; i++) {
5861 mask = pageflag_names[i].mask;
5862 if ((flags & mask) != mask)
5866 printk("%s%s", delim, pageflag_names[i].name);
5870 /* check for left over flags */
5872 printk("%s%#lx", delim, flags);
5877 void dump_page(struct page *page)
5880 "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
5881 page, atomic_read(&page->_count), page_mapcount(page),
5882 page->mapping, page->index);
5883 dump_page_flags(page->flags);
5884 mem_cgroup_print_bad_page(page);