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/compiler.h>
25 #include <linux/kernel.h>
26 #include <linux/kmemcheck.h>
27 #include <linux/module.h>
28 #include <linux/suspend.h>
29 #include <linux/pagevec.h>
30 #include <linux/blkdev.h>
31 #include <linux/slab.h>
32 #include <linux/oom.h>
33 #include <linux/notifier.h>
34 #include <linux/topology.h>
35 #include <linux/sysctl.h>
36 #include <linux/cpu.h>
37 #include <linux/cpuset.h>
38 #include <linux/memory_hotplug.h>
39 #include <linux/nodemask.h>
40 #include <linux/vmalloc.h>
41 #include <linux/mempolicy.h>
42 #include <linux/stop_machine.h>
43 #include <linux/sort.h>
44 #include <linux/pfn.h>
45 #include <linux/backing-dev.h>
46 #include <linux/fault-inject.h>
47 #include <linux/page-isolation.h>
48 #include <linux/page_cgroup.h>
49 #include <linux/debugobjects.h>
50 #include <linux/kmemleak.h>
51 #include <linux/memory.h>
52 #include <linux/compaction.h>
53 #include <trace/events/kmem.h>
54 #include <linux/ftrace_event.h>
56 #include <asm/tlbflush.h>
57 #include <asm/div64.h>
61 * Array of node states.
63 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
64 [N_POSSIBLE] = NODE_MASK_ALL,
65 [N_ONLINE] = { { [0] = 1UL } },
67 [N_NORMAL_MEMORY] = { { [0] = 1UL } },
69 [N_HIGH_MEMORY] = { { [0] = 1UL } },
71 [N_CPU] = { { [0] = 1UL } },
74 EXPORT_SYMBOL(node_states);
76 unsigned long totalram_pages __read_mostly;
77 unsigned long totalreserve_pages __read_mostly;
78 int percpu_pagelist_fraction;
79 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
81 #ifdef CONFIG_PM_SLEEP
83 * The following functions are used by the suspend/hibernate code to temporarily
84 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
85 * while devices are suspended. To avoid races with the suspend/hibernate code,
86 * they should always be called with pm_mutex held (gfp_allowed_mask also should
87 * only be modified with pm_mutex held, unless the suspend/hibernate code is
88 * guaranteed not to run in parallel with that modification).
90 void set_gfp_allowed_mask(gfp_t mask)
92 WARN_ON(!mutex_is_locked(&pm_mutex));
93 gfp_allowed_mask = mask;
96 gfp_t clear_gfp_allowed_mask(gfp_t mask)
98 gfp_t ret = gfp_allowed_mask;
100 WARN_ON(!mutex_is_locked(&pm_mutex));
101 gfp_allowed_mask &= ~mask;
104 #endif /* CONFIG_PM_SLEEP */
106 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
107 int pageblock_order __read_mostly;
110 static void __free_pages_ok(struct page *page, unsigned int order);
113 * results with 256, 32 in the lowmem_reserve sysctl:
114 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
115 * 1G machine -> (16M dma, 784M normal, 224M high)
116 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
117 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
118 * HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
120 * TBD: should special case ZONE_DMA32 machines here - in those we normally
121 * don't need any ZONE_NORMAL reservation
123 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
124 #ifdef CONFIG_ZONE_DMA
127 #ifdef CONFIG_ZONE_DMA32
130 #ifdef CONFIG_HIGHMEM
136 EXPORT_SYMBOL(totalram_pages);
138 static char * const zone_names[MAX_NR_ZONES] = {
139 #ifdef CONFIG_ZONE_DMA
142 #ifdef CONFIG_ZONE_DMA32
146 #ifdef CONFIG_HIGHMEM
152 int min_free_kbytes = 1024;
154 static unsigned long __meminitdata nr_kernel_pages;
155 static unsigned long __meminitdata nr_all_pages;
156 static unsigned long __meminitdata dma_reserve;
158 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
160 * MAX_ACTIVE_REGIONS determines the maximum number of distinct
161 * ranges of memory (RAM) that may be registered with add_active_range().
162 * Ranges passed to add_active_range() will be merged if possible
163 * so the number of times add_active_range() can be called is
164 * related to the number of nodes and the number of holes
166 #ifdef CONFIG_MAX_ACTIVE_REGIONS
167 /* Allow an architecture to set MAX_ACTIVE_REGIONS to save memory */
168 #define MAX_ACTIVE_REGIONS CONFIG_MAX_ACTIVE_REGIONS
170 #if MAX_NUMNODES >= 32
171 /* If there can be many nodes, allow up to 50 holes per node */
172 #define MAX_ACTIVE_REGIONS (MAX_NUMNODES*50)
174 /* By default, allow up to 256 distinct regions */
175 #define MAX_ACTIVE_REGIONS 256
179 static struct node_active_region __meminitdata early_node_map[MAX_ACTIVE_REGIONS];
180 static int __meminitdata nr_nodemap_entries;
181 static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
182 static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
183 static unsigned long __initdata required_kernelcore;
184 static unsigned long __initdata required_movablecore;
185 static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
187 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
189 EXPORT_SYMBOL(movable_zone);
190 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
193 int nr_node_ids __read_mostly = MAX_NUMNODES;
194 int nr_online_nodes __read_mostly = 1;
195 EXPORT_SYMBOL(nr_node_ids);
196 EXPORT_SYMBOL(nr_online_nodes);
199 int page_group_by_mobility_disabled __read_mostly;
201 static void set_pageblock_migratetype(struct page *page, int migratetype)
204 if (unlikely(page_group_by_mobility_disabled))
205 migratetype = MIGRATE_UNMOVABLE;
207 set_pageblock_flags_group(page, (unsigned long)migratetype,
208 PB_migrate, PB_migrate_end);
211 bool oom_killer_disabled __read_mostly;
213 #ifdef CONFIG_DEBUG_VM
214 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
218 unsigned long pfn = page_to_pfn(page);
221 seq = zone_span_seqbegin(zone);
222 if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
224 else if (pfn < zone->zone_start_pfn)
226 } while (zone_span_seqretry(zone, seq));
231 static int page_is_consistent(struct zone *zone, struct page *page)
233 if (!pfn_valid_within(page_to_pfn(page)))
235 if (zone != page_zone(page))
241 * Temporary debugging check for pages not lying within a given zone.
243 static int bad_range(struct zone *zone, struct page *page)
245 if (page_outside_zone_boundaries(zone, page))
247 if (!page_is_consistent(zone, page))
253 static inline int bad_range(struct zone *zone, struct page *page)
259 static void bad_page(struct page *page)
261 static unsigned long resume;
262 static unsigned long nr_shown;
263 static unsigned long nr_unshown;
265 /* Don't complain about poisoned pages */
266 if (PageHWPoison(page)) {
267 __ClearPageBuddy(page);
272 * Allow a burst of 60 reports, then keep quiet for that minute;
273 * or allow a steady drip of one report per second.
275 if (nr_shown == 60) {
276 if (time_before(jiffies, resume)) {
282 "BUG: Bad page state: %lu messages suppressed\n",
289 resume = jiffies + 60 * HZ;
291 printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n",
292 current->comm, page_to_pfn(page));
297 /* Leave bad fields for debug, except PageBuddy could make trouble */
298 __ClearPageBuddy(page);
299 add_taint(TAINT_BAD_PAGE);
303 * Higher-order pages are called "compound pages". They are structured thusly:
305 * The first PAGE_SIZE page is called the "head page".
307 * The remaining PAGE_SIZE pages are called "tail pages".
309 * All pages have PG_compound set. All pages have their ->private pointing at
310 * the head page (even the head page has this).
312 * The first tail page's ->lru.next holds the address of the compound page's
313 * put_page() function. Its ->lru.prev holds the order of allocation.
314 * This usage means that zero-order pages may not be compound.
317 static void free_compound_page(struct page *page)
319 __free_pages_ok(page, compound_order(page));
322 void prep_compound_page(struct page *page, unsigned long order)
325 int nr_pages = 1 << order;
327 set_compound_page_dtor(page, free_compound_page);
328 set_compound_order(page, order);
330 for (i = 1; i < nr_pages; i++) {
331 struct page *p = page + i;
334 p->first_page = page;
338 static int destroy_compound_page(struct page *page, unsigned long order)
341 int nr_pages = 1 << order;
344 if (unlikely(compound_order(page) != order) ||
345 unlikely(!PageHead(page))) {
350 __ClearPageHead(page);
352 for (i = 1; i < nr_pages; i++) {
353 struct page *p = page + i;
355 if (unlikely(!PageTail(p) || (p->first_page != page))) {
365 static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
370 * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
371 * and __GFP_HIGHMEM from hard or soft interrupt context.
373 VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
374 for (i = 0; i < (1 << order); i++)
375 clear_highpage(page + i);
378 static inline void set_page_order(struct page *page, int order)
380 set_page_private(page, order);
381 __SetPageBuddy(page);
384 static inline void rmv_page_order(struct page *page)
386 __ClearPageBuddy(page);
387 set_page_private(page, 0);
391 * Locate the struct page for both the matching buddy in our
392 * pair (buddy1) and the combined O(n+1) page they form (page).
394 * 1) Any buddy B1 will have an order O twin B2 which satisfies
395 * the following equation:
397 * For example, if the starting buddy (buddy2) is #8 its order
399 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
401 * 2) Any buddy B will have an order O+1 parent P which
402 * satisfies the following equation:
405 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
407 static inline struct page *
408 __page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
410 unsigned long buddy_idx = page_idx ^ (1 << order);
412 return page + (buddy_idx - page_idx);
415 static inline unsigned long
416 __find_combined_index(unsigned long page_idx, unsigned int order)
418 return (page_idx & ~(1 << order));
422 * This function checks whether a page is free && is the buddy
423 * we can do coalesce a page and its buddy if
424 * (a) the buddy is not in a hole &&
425 * (b) the buddy is in the buddy system &&
426 * (c) a page and its buddy have the same order &&
427 * (d) a page and its buddy are in the same zone.
429 * For recording whether a page is in the buddy system, we use PG_buddy.
430 * Setting, clearing, and testing PG_buddy is serialized by zone->lock.
432 * For recording page's order, we use page_private(page).
434 static inline int page_is_buddy(struct page *page, struct page *buddy,
437 if (!pfn_valid_within(page_to_pfn(buddy)))
440 if (page_zone_id(page) != page_zone_id(buddy))
443 if (PageBuddy(buddy) && page_order(buddy) == order) {
444 VM_BUG_ON(page_count(buddy) != 0);
451 * Freeing function for a buddy system allocator.
453 * The concept of a buddy system is to maintain direct-mapped table
454 * (containing bit values) for memory blocks of various "orders".
455 * The bottom level table contains the map for the smallest allocatable
456 * units of memory (here, pages), and each level above it describes
457 * pairs of units from the levels below, hence, "buddies".
458 * At a high level, all that happens here is marking the table entry
459 * at the bottom level available, and propagating the changes upward
460 * as necessary, plus some accounting needed to play nicely with other
461 * parts of the VM system.
462 * At each level, we keep a list of pages, which are heads of continuous
463 * free pages of length of (1 << order) and marked with PG_buddy. Page's
464 * order is recorded in page_private(page) field.
465 * So when we are allocating or freeing one, we can derive the state of the
466 * other. That is, if we allocate a small block, and both were
467 * free, the remainder of the region must be split into blocks.
468 * If a block is freed, and its buddy is also free, then this
469 * triggers coalescing into a block of larger size.
474 static inline void __free_one_page(struct page *page,
475 struct zone *zone, unsigned int order,
478 unsigned long page_idx;
479 unsigned long combined_idx;
482 if (unlikely(PageCompound(page)))
483 if (unlikely(destroy_compound_page(page, order)))
486 VM_BUG_ON(migratetype == -1);
488 page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
490 VM_BUG_ON(page_idx & ((1 << order) - 1));
491 VM_BUG_ON(bad_range(zone, page));
493 while (order < MAX_ORDER-1) {
494 buddy = __page_find_buddy(page, page_idx, order);
495 if (!page_is_buddy(page, buddy, order))
498 /* Our buddy is free, merge with it and move up one order. */
499 list_del(&buddy->lru);
500 zone->free_area[order].nr_free--;
501 rmv_page_order(buddy);
502 combined_idx = __find_combined_index(page_idx, order);
503 page = page + (combined_idx - page_idx);
504 page_idx = combined_idx;
507 set_page_order(page, order);
510 * If this is not the largest possible page, check if the buddy
511 * of the next-highest order is free. If it is, it's possible
512 * that pages are being freed that will coalesce soon. In case,
513 * that is happening, add the free page to the tail of the list
514 * so it's less likely to be used soon and more likely to be merged
515 * as a higher order page
517 if ((order < MAX_ORDER-1) && pfn_valid_within(page_to_pfn(buddy))) {
518 struct page *higher_page, *higher_buddy;
519 combined_idx = __find_combined_index(page_idx, order);
520 higher_page = page + combined_idx - page_idx;
521 higher_buddy = __page_find_buddy(higher_page, combined_idx, order + 1);
522 if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
523 list_add_tail(&page->lru,
524 &zone->free_area[order].free_list[migratetype]);
529 list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
531 zone->free_area[order].nr_free++;
535 * free_page_mlock() -- clean up attempts to free and mlocked() page.
536 * Page should not be on lru, so no need to fix that up.
537 * free_pages_check() will verify...
539 static inline void free_page_mlock(struct page *page)
541 __dec_zone_page_state(page, NR_MLOCK);
542 __count_vm_event(UNEVICTABLE_MLOCKFREED);
545 static inline int free_pages_check(struct page *page)
547 if (unlikely(page_mapcount(page) |
548 (page->mapping != NULL) |
549 (atomic_read(&page->_count) != 0) |
550 (page->flags & PAGE_FLAGS_CHECK_AT_FREE))) {
554 if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
555 page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
560 * Frees a number of pages from the PCP lists
561 * Assumes all pages on list are in same zone, and of same order.
562 * count is the number of pages to free.
564 * If the zone was previously in an "all pages pinned" state then look to
565 * see if this freeing clears that state.
567 * And clear the zone's pages_scanned counter, to hold off the "all pages are
568 * pinned" detection logic.
570 static void free_pcppages_bulk(struct zone *zone, int count,
571 struct per_cpu_pages *pcp)
576 spin_lock(&zone->lock);
577 zone->all_unreclaimable = 0;
578 zone->pages_scanned = 0;
580 __mod_zone_page_state(zone, NR_FREE_PAGES, count);
583 struct list_head *list;
586 * Remove pages from lists in a round-robin fashion. A
587 * batch_free count is maintained that is incremented when an
588 * empty list is encountered. This is so more pages are freed
589 * off fuller lists instead of spinning excessively around empty
594 if (++migratetype == MIGRATE_PCPTYPES)
596 list = &pcp->lists[migratetype];
597 } while (list_empty(list));
600 page = list_entry(list->prev, struct page, lru);
601 /* must delete as __free_one_page list manipulates */
602 list_del(&page->lru);
603 /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
604 __free_one_page(page, zone, 0, page_private(page));
605 trace_mm_page_pcpu_drain(page, 0, page_private(page));
606 } while (--count && --batch_free && !list_empty(list));
608 spin_unlock(&zone->lock);
611 static void free_one_page(struct zone *zone, struct page *page, int order,
614 spin_lock(&zone->lock);
615 zone->all_unreclaimable = 0;
616 zone->pages_scanned = 0;
618 __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
619 __free_one_page(page, zone, order, migratetype);
620 spin_unlock(&zone->lock);
623 static void __free_pages_ok(struct page *page, unsigned int order)
628 int wasMlocked = __TestClearPageMlocked(page);
630 trace_mm_page_free_direct(page, order);
631 kmemcheck_free_shadow(page, order);
633 for (i = 0 ; i < (1 << order) ; ++i)
634 bad += free_pages_check(page + i);
638 if (!PageHighMem(page)) {
639 debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
640 debug_check_no_obj_freed(page_address(page),
643 arch_free_page(page, order);
644 kernel_map_pages(page, 1 << order, 0);
646 local_irq_save(flags);
647 if (unlikely(wasMlocked))
648 free_page_mlock(page);
649 __count_vm_events(PGFREE, 1 << order);
650 free_one_page(page_zone(page), page, order,
651 get_pageblock_migratetype(page));
652 local_irq_restore(flags);
656 * permit the bootmem allocator to evade page validation on high-order frees
658 void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
661 __ClearPageReserved(page);
662 set_page_count(page, 0);
663 set_page_refcounted(page);
669 for (loop = 0; loop < BITS_PER_LONG; loop++) {
670 struct page *p = &page[loop];
672 if (loop + 1 < BITS_PER_LONG)
674 __ClearPageReserved(p);
675 set_page_count(p, 0);
678 set_page_refcounted(page);
679 __free_pages(page, order);
685 * The order of subdivision here is critical for the IO subsystem.
686 * Please do not alter this order without good reasons and regression
687 * testing. Specifically, as large blocks of memory are subdivided,
688 * the order in which smaller blocks are delivered depends on the order
689 * they're subdivided in this function. This is the primary factor
690 * influencing the order in which pages are delivered to the IO
691 * subsystem according to empirical testing, and this is also justified
692 * by considering the behavior of a buddy system containing a single
693 * large block of memory acted on by a series of small allocations.
694 * This behavior is a critical factor in sglist merging's success.
698 static inline void expand(struct zone *zone, struct page *page,
699 int low, int high, struct free_area *area,
702 unsigned long size = 1 << high;
708 VM_BUG_ON(bad_range(zone, &page[size]));
709 list_add(&page[size].lru, &area->free_list[migratetype]);
711 set_page_order(&page[size], high);
716 * This page is about to be returned from the page allocator
718 static inline int check_new_page(struct page *page)
720 if (unlikely(page_mapcount(page) |
721 (page->mapping != NULL) |
722 (atomic_read(&page->_count) != 0) |
723 (page->flags & PAGE_FLAGS_CHECK_AT_PREP))) {
730 static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
734 for (i = 0; i < (1 << order); i++) {
735 struct page *p = page + i;
736 if (unlikely(check_new_page(p)))
740 set_page_private(page, 0);
741 set_page_refcounted(page);
743 arch_alloc_page(page, order);
744 kernel_map_pages(page, 1 << order, 1);
746 if (gfp_flags & __GFP_ZERO)
747 prep_zero_page(page, order, gfp_flags);
749 if (order && (gfp_flags & __GFP_COMP))
750 prep_compound_page(page, order);
756 * Go through the free lists for the given migratetype and remove
757 * the smallest available page from the freelists
760 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
763 unsigned int current_order;
764 struct free_area * area;
767 /* Find a page of the appropriate size in the preferred list */
768 for (current_order = order; current_order < MAX_ORDER; ++current_order) {
769 area = &(zone->free_area[current_order]);
770 if (list_empty(&area->free_list[migratetype]))
773 page = list_entry(area->free_list[migratetype].next,
775 list_del(&page->lru);
776 rmv_page_order(page);
778 expand(zone, page, order, current_order, area, migratetype);
787 * This array describes the order lists are fallen back to when
788 * the free lists for the desirable migrate type are depleted
790 static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = {
791 [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
792 [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_RESERVE },
793 [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
794 [MIGRATE_RESERVE] = { MIGRATE_RESERVE, MIGRATE_RESERVE, MIGRATE_RESERVE }, /* Never used */
798 * Move the free pages in a range to the free lists of the requested type.
799 * Note that start_page and end_pages are not aligned on a pageblock
800 * boundary. If alignment is required, use move_freepages_block()
802 static int move_freepages(struct zone *zone,
803 struct page *start_page, struct page *end_page,
810 #ifndef CONFIG_HOLES_IN_ZONE
812 * page_zone is not safe to call in this context when
813 * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
814 * anyway as we check zone boundaries in move_freepages_block().
815 * Remove at a later date when no bug reports exist related to
816 * grouping pages by mobility
818 BUG_ON(page_zone(start_page) != page_zone(end_page));
821 for (page = start_page; page <= end_page;) {
822 /* Make sure we are not inadvertently changing nodes */
823 VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
825 if (!pfn_valid_within(page_to_pfn(page))) {
830 if (!PageBuddy(page)) {
835 order = page_order(page);
836 list_del(&page->lru);
838 &zone->free_area[order].free_list[migratetype]);
840 pages_moved += 1 << order;
846 static int move_freepages_block(struct zone *zone, struct page *page,
849 unsigned long start_pfn, end_pfn;
850 struct page *start_page, *end_page;
852 start_pfn = page_to_pfn(page);
853 start_pfn = start_pfn & ~(pageblock_nr_pages-1);
854 start_page = pfn_to_page(start_pfn);
855 end_page = start_page + pageblock_nr_pages - 1;
856 end_pfn = start_pfn + pageblock_nr_pages - 1;
858 /* Do not cross zone boundaries */
859 if (start_pfn < zone->zone_start_pfn)
861 if (end_pfn >= zone->zone_start_pfn + zone->spanned_pages)
864 return move_freepages(zone, start_page, end_page, migratetype);
867 static void change_pageblock_range(struct page *pageblock_page,
868 int start_order, int migratetype)
870 int nr_pageblocks = 1 << (start_order - pageblock_order);
872 while (nr_pageblocks--) {
873 set_pageblock_migratetype(pageblock_page, migratetype);
874 pageblock_page += pageblock_nr_pages;
878 /* Remove an element from the buddy allocator from the fallback list */
879 static inline struct page *
880 __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
882 struct free_area * area;
887 /* Find the largest possible block of pages in the other list */
888 for (current_order = MAX_ORDER-1; current_order >= order;
890 for (i = 0; i < MIGRATE_TYPES - 1; i++) {
891 migratetype = fallbacks[start_migratetype][i];
893 /* MIGRATE_RESERVE handled later if necessary */
894 if (migratetype == MIGRATE_RESERVE)
897 area = &(zone->free_area[current_order]);
898 if (list_empty(&area->free_list[migratetype]))
901 page = list_entry(area->free_list[migratetype].next,
906 * If breaking a large block of pages, move all free
907 * pages to the preferred allocation list. If falling
908 * back for a reclaimable kernel allocation, be more
909 * agressive about taking ownership of free pages
911 if (unlikely(current_order >= (pageblock_order >> 1)) ||
912 start_migratetype == MIGRATE_RECLAIMABLE ||
913 page_group_by_mobility_disabled) {
915 pages = move_freepages_block(zone, page,
918 /* Claim the whole block if over half of it is free */
919 if (pages >= (1 << (pageblock_order-1)) ||
920 page_group_by_mobility_disabled)
921 set_pageblock_migratetype(page,
924 migratetype = start_migratetype;
927 /* Remove the page from the freelists */
928 list_del(&page->lru);
929 rmv_page_order(page);
931 /* Take ownership for orders >= pageblock_order */
932 if (current_order >= pageblock_order)
933 change_pageblock_range(page, current_order,
936 expand(zone, page, order, current_order, area, migratetype);
938 trace_mm_page_alloc_extfrag(page, order, current_order,
939 start_migratetype, migratetype);
949 * Do the hard work of removing an element from the buddy allocator.
950 * Call me with the zone->lock already held.
952 static struct page *__rmqueue(struct zone *zone, unsigned int order,
958 page = __rmqueue_smallest(zone, order, migratetype);
960 if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
961 page = __rmqueue_fallback(zone, order, migratetype);
964 * Use MIGRATE_RESERVE rather than fail an allocation. goto
965 * is used because __rmqueue_smallest is an inline function
966 * and we want just one call site
969 migratetype = MIGRATE_RESERVE;
974 trace_mm_page_alloc_zone_locked(page, order, migratetype);
979 * Obtain a specified number of elements from the buddy allocator, all under
980 * a single hold of the lock, for efficiency. Add them to the supplied list.
981 * Returns the number of new pages which were placed at *list.
983 static int rmqueue_bulk(struct zone *zone, unsigned int order,
984 unsigned long count, struct list_head *list,
985 int migratetype, int cold)
989 spin_lock(&zone->lock);
990 for (i = 0; i < count; ++i) {
991 struct page *page = __rmqueue(zone, order, migratetype);
992 if (unlikely(page == NULL))
996 * Split buddy pages returned by expand() are received here
997 * in physical page order. The page is added to the callers and
998 * list and the list head then moves forward. From the callers
999 * perspective, the linked list is ordered by page number in
1000 * some conditions. This is useful for IO devices that can
1001 * merge IO requests if the physical pages are ordered
1004 if (likely(cold == 0))
1005 list_add(&page->lru, list);
1007 list_add_tail(&page->lru, list);
1008 set_page_private(page, migratetype);
1011 __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
1012 spin_unlock(&zone->lock);
1018 * Called from the vmstat counter updater to drain pagesets of this
1019 * currently executing processor on remote nodes after they have
1022 * Note that this function must be called with the thread pinned to
1023 * a single processor.
1025 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
1027 unsigned long flags;
1030 local_irq_save(flags);
1031 if (pcp->count >= pcp->batch)
1032 to_drain = pcp->batch;
1034 to_drain = pcp->count;
1035 free_pcppages_bulk(zone, to_drain, pcp);
1036 pcp->count -= to_drain;
1037 local_irq_restore(flags);
1042 * Drain pages of the indicated processor.
1044 * The processor must either be the current processor and the
1045 * thread pinned to the current processor or a processor that
1048 static void drain_pages(unsigned int cpu)
1050 unsigned long flags;
1053 for_each_populated_zone(zone) {
1054 struct per_cpu_pageset *pset;
1055 struct per_cpu_pages *pcp;
1057 local_irq_save(flags);
1058 pset = per_cpu_ptr(zone->pageset, cpu);
1061 free_pcppages_bulk(zone, pcp->count, pcp);
1063 local_irq_restore(flags);
1068 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
1070 void drain_local_pages(void *arg)
1072 drain_pages(smp_processor_id());
1076 * Spill all the per-cpu pages from all CPUs back into the buddy allocator
1078 void drain_all_pages(void)
1080 on_each_cpu(drain_local_pages, NULL, 1);
1083 #ifdef CONFIG_HIBERNATION
1085 void mark_free_pages(struct zone *zone)
1087 unsigned long pfn, max_zone_pfn;
1088 unsigned long flags;
1090 struct list_head *curr;
1092 if (!zone->spanned_pages)
1095 spin_lock_irqsave(&zone->lock, flags);
1097 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1098 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1099 if (pfn_valid(pfn)) {
1100 struct page *page = pfn_to_page(pfn);
1102 if (!swsusp_page_is_forbidden(page))
1103 swsusp_unset_page_free(page);
1106 for_each_migratetype_order(order, t) {
1107 list_for_each(curr, &zone->free_area[order].free_list[t]) {
1110 pfn = page_to_pfn(list_entry(curr, struct page, lru));
1111 for (i = 0; i < (1UL << order); i++)
1112 swsusp_set_page_free(pfn_to_page(pfn + i));
1115 spin_unlock_irqrestore(&zone->lock, flags);
1117 #endif /* CONFIG_PM */
1120 * Free a 0-order page
1121 * cold == 1 ? free a cold page : free a hot page
1123 void free_hot_cold_page(struct page *page, int cold)
1125 struct zone *zone = page_zone(page);
1126 struct per_cpu_pages *pcp;
1127 unsigned long flags;
1129 int wasMlocked = __TestClearPageMlocked(page);
1131 trace_mm_page_free_direct(page, 0);
1132 kmemcheck_free_shadow(page, 0);
1135 page->mapping = NULL;
1136 if (free_pages_check(page))
1139 if (!PageHighMem(page)) {
1140 debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
1141 debug_check_no_obj_freed(page_address(page), PAGE_SIZE);
1143 arch_free_page(page, 0);
1144 kernel_map_pages(page, 1, 0);
1146 migratetype = get_pageblock_migratetype(page);
1147 set_page_private(page, migratetype);
1148 local_irq_save(flags);
1149 if (unlikely(wasMlocked))
1150 free_page_mlock(page);
1151 __count_vm_event(PGFREE);
1154 * We only track unmovable, reclaimable and movable on pcp lists.
1155 * Free ISOLATE pages back to the allocator because they are being
1156 * offlined but treat RESERVE as movable pages so we can get those
1157 * areas back if necessary. Otherwise, we may have to free
1158 * excessively into the page allocator
1160 if (migratetype >= MIGRATE_PCPTYPES) {
1161 if (unlikely(migratetype == MIGRATE_ISOLATE)) {
1162 free_one_page(zone, page, 0, migratetype);
1165 migratetype = MIGRATE_MOVABLE;
1168 pcp = &this_cpu_ptr(zone->pageset)->pcp;
1170 list_add_tail(&page->lru, &pcp->lists[migratetype]);
1172 list_add(&page->lru, &pcp->lists[migratetype]);
1174 if (pcp->count >= pcp->high) {
1175 free_pcppages_bulk(zone, pcp->batch, pcp);
1176 pcp->count -= pcp->batch;
1180 local_irq_restore(flags);
1184 * split_page takes a non-compound higher-order page, and splits it into
1185 * n (1<<order) sub-pages: page[0..n]
1186 * Each sub-page must be freed individually.
1188 * Note: this is probably too low level an operation for use in drivers.
1189 * Please consult with lkml before using this in your driver.
1191 void split_page(struct page *page, unsigned int order)
1195 VM_BUG_ON(PageCompound(page));
1196 VM_BUG_ON(!page_count(page));
1198 #ifdef CONFIG_KMEMCHECK
1200 * Split shadow pages too, because free(page[0]) would
1201 * otherwise free the whole shadow.
1203 if (kmemcheck_page_is_tracked(page))
1204 split_page(virt_to_page(page[0].shadow), order);
1207 for (i = 1; i < (1 << order); i++)
1208 set_page_refcounted(page + i);
1212 * Similar to split_page except the page is already free. As this is only
1213 * being used for migration, the migratetype of the block also changes.
1214 * As this is called with interrupts disabled, the caller is responsible
1215 * for calling arch_alloc_page() and kernel_map_page() after interrupts
1218 * Note: this is probably too low level an operation for use in drivers.
1219 * Please consult with lkml before using this in your driver.
1221 int split_free_page(struct page *page)
1224 unsigned long watermark;
1227 BUG_ON(!PageBuddy(page));
1229 zone = page_zone(page);
1230 order = page_order(page);
1232 /* Obey watermarks as if the page was being allocated */
1233 watermark = low_wmark_pages(zone) + (1 << order);
1234 if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
1237 /* Remove page from free list */
1238 list_del(&page->lru);
1239 zone->free_area[order].nr_free--;
1240 rmv_page_order(page);
1241 __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order));
1243 /* Split into individual pages */
1244 set_page_refcounted(page);
1245 split_page(page, order);
1247 if (order >= pageblock_order - 1) {
1248 struct page *endpage = page + (1 << order) - 1;
1249 for (; page < endpage; page += pageblock_nr_pages)
1250 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1257 * Really, prep_compound_page() should be called from __rmqueue_bulk(). But
1258 * we cheat by calling it from here, in the order > 0 path. Saves a branch
1262 struct page *buffered_rmqueue(struct zone *preferred_zone,
1263 struct zone *zone, int order, gfp_t gfp_flags,
1266 unsigned long flags;
1268 int cold = !!(gfp_flags & __GFP_COLD);
1271 if (likely(order == 0)) {
1272 struct per_cpu_pages *pcp;
1273 struct list_head *list;
1275 local_irq_save(flags);
1276 pcp = &this_cpu_ptr(zone->pageset)->pcp;
1277 list = &pcp->lists[migratetype];
1278 if (list_empty(list)) {
1279 pcp->count += rmqueue_bulk(zone, 0,
1282 if (unlikely(list_empty(list)))
1287 page = list_entry(list->prev, struct page, lru);
1289 page = list_entry(list->next, struct page, lru);
1291 list_del(&page->lru);
1294 if (unlikely(gfp_flags & __GFP_NOFAIL)) {
1296 * __GFP_NOFAIL is not to be used in new code.
1298 * All __GFP_NOFAIL callers should be fixed so that they
1299 * properly detect and handle allocation failures.
1301 * We most definitely don't want callers attempting to
1302 * allocate greater than order-1 page units with
1305 WARN_ON_ONCE(order > 1);
1307 spin_lock_irqsave(&zone->lock, flags);
1308 page = __rmqueue(zone, order, migratetype);
1309 spin_unlock(&zone->lock);
1312 __mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
1315 __count_zone_vm_events(PGALLOC, zone, 1 << order);
1316 zone_statistics(preferred_zone, zone);
1317 local_irq_restore(flags);
1319 VM_BUG_ON(bad_range(zone, page));
1320 if (prep_new_page(page, order, gfp_flags))
1325 local_irq_restore(flags);
1329 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
1330 #define ALLOC_WMARK_MIN WMARK_MIN
1331 #define ALLOC_WMARK_LOW WMARK_LOW
1332 #define ALLOC_WMARK_HIGH WMARK_HIGH
1333 #define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */
1335 /* Mask to get the watermark bits */
1336 #define ALLOC_WMARK_MASK (ALLOC_NO_WATERMARKS-1)
1338 #define ALLOC_HARDER 0x10 /* try to alloc harder */
1339 #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
1340 #define ALLOC_CPUSET 0x40 /* check for correct cpuset */
1342 #ifdef CONFIG_FAIL_PAGE_ALLOC
1344 static struct fail_page_alloc_attr {
1345 struct fault_attr attr;
1347 u32 ignore_gfp_highmem;
1348 u32 ignore_gfp_wait;
1351 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1353 struct dentry *ignore_gfp_highmem_file;
1354 struct dentry *ignore_gfp_wait_file;
1355 struct dentry *min_order_file;
1357 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1359 } fail_page_alloc = {
1360 .attr = FAULT_ATTR_INITIALIZER,
1361 .ignore_gfp_wait = 1,
1362 .ignore_gfp_highmem = 1,
1366 static int __init setup_fail_page_alloc(char *str)
1368 return setup_fault_attr(&fail_page_alloc.attr, str);
1370 __setup("fail_page_alloc=", setup_fail_page_alloc);
1372 static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1374 if (order < fail_page_alloc.min_order)
1376 if (gfp_mask & __GFP_NOFAIL)
1378 if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1380 if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1383 return should_fail(&fail_page_alloc.attr, 1 << order);
1386 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1388 static int __init fail_page_alloc_debugfs(void)
1390 mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1394 err = init_fault_attr_dentries(&fail_page_alloc.attr,
1398 dir = fail_page_alloc.attr.dentries.dir;
1400 fail_page_alloc.ignore_gfp_wait_file =
1401 debugfs_create_bool("ignore-gfp-wait", mode, dir,
1402 &fail_page_alloc.ignore_gfp_wait);
1404 fail_page_alloc.ignore_gfp_highmem_file =
1405 debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1406 &fail_page_alloc.ignore_gfp_highmem);
1407 fail_page_alloc.min_order_file =
1408 debugfs_create_u32("min-order", mode, dir,
1409 &fail_page_alloc.min_order);
1411 if (!fail_page_alloc.ignore_gfp_wait_file ||
1412 !fail_page_alloc.ignore_gfp_highmem_file ||
1413 !fail_page_alloc.min_order_file) {
1415 debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
1416 debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
1417 debugfs_remove(fail_page_alloc.min_order_file);
1418 cleanup_fault_attr_dentries(&fail_page_alloc.attr);
1424 late_initcall(fail_page_alloc_debugfs);
1426 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1428 #else /* CONFIG_FAIL_PAGE_ALLOC */
1430 static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1435 #endif /* CONFIG_FAIL_PAGE_ALLOC */
1438 * Return 1 if free pages are above 'mark'. This takes into account the order
1439 * of the allocation.
1441 int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1442 int classzone_idx, int alloc_flags)
1444 /* free_pages my go negative - that's OK */
1446 long free_pages = zone_page_state(z, NR_FREE_PAGES) - (1 << order) + 1;
1449 if (alloc_flags & ALLOC_HIGH)
1451 if (alloc_flags & ALLOC_HARDER)
1454 if (free_pages <= min + z->lowmem_reserve[classzone_idx])
1456 for (o = 0; o < order; o++) {
1457 /* At the next order, this order's pages become unavailable */
1458 free_pages -= z->free_area[o].nr_free << o;
1460 /* Require fewer higher order pages to be free */
1463 if (free_pages <= min)
1471 * zlc_setup - Setup for "zonelist cache". Uses cached zone data to
1472 * skip over zones that are not allowed by the cpuset, or that have
1473 * been recently (in last second) found to be nearly full. See further
1474 * comments in mmzone.h. Reduces cache footprint of zonelist scans
1475 * that have to skip over a lot of full or unallowed zones.
1477 * If the zonelist cache is present in the passed in zonelist, then
1478 * returns a pointer to the allowed node mask (either the current
1479 * tasks mems_allowed, or node_states[N_HIGH_MEMORY].)
1481 * If the zonelist cache is not available for this zonelist, does
1482 * nothing and returns NULL.
1484 * If the fullzones BITMAP in the zonelist cache is stale (more than
1485 * a second since last zap'd) then we zap it out (clear its bits.)
1487 * We hold off even calling zlc_setup, until after we've checked the
1488 * first zone in the zonelist, on the theory that most allocations will
1489 * be satisfied from that first zone, so best to examine that zone as
1490 * quickly as we can.
1492 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1494 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1495 nodemask_t *allowednodes; /* zonelist_cache approximation */
1497 zlc = zonelist->zlcache_ptr;
1501 if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1502 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1503 zlc->last_full_zap = jiffies;
1506 allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1507 &cpuset_current_mems_allowed :
1508 &node_states[N_HIGH_MEMORY];
1509 return allowednodes;
1513 * Given 'z' scanning a zonelist, run a couple of quick checks to see
1514 * if it is worth looking at further for free memory:
1515 * 1) Check that the zone isn't thought to be full (doesn't have its
1516 * bit set in the zonelist_cache fullzones BITMAP).
1517 * 2) Check that the zones node (obtained from the zonelist_cache
1518 * z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1519 * Return true (non-zero) if zone is worth looking at further, or
1520 * else return false (zero) if it is not.
1522 * This check -ignores- the distinction between various watermarks,
1523 * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ... If a zone is
1524 * found to be full for any variation of these watermarks, it will
1525 * be considered full for up to one second by all requests, unless
1526 * we are so low on memory on all allowed nodes that we are forced
1527 * into the second scan of the zonelist.
1529 * In the second scan we ignore this zonelist cache and exactly
1530 * apply the watermarks to all zones, even it is slower to do so.
1531 * We are low on memory in the second scan, and should leave no stone
1532 * unturned looking for a free page.
1534 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1535 nodemask_t *allowednodes)
1537 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1538 int i; /* index of *z in zonelist zones */
1539 int n; /* node that zone *z is on */
1541 zlc = zonelist->zlcache_ptr;
1545 i = z - zonelist->_zonerefs;
1548 /* This zone is worth trying if it is allowed but not full */
1549 return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1553 * Given 'z' scanning a zonelist, set the corresponding bit in
1554 * zlc->fullzones, so that subsequent attempts to allocate a page
1555 * from that zone don't waste time re-examining it.
1557 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1559 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1560 int i; /* index of *z in zonelist zones */
1562 zlc = zonelist->zlcache_ptr;
1566 i = z - zonelist->_zonerefs;
1568 set_bit(i, zlc->fullzones);
1571 #else /* CONFIG_NUMA */
1573 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1578 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1579 nodemask_t *allowednodes)
1584 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1587 #endif /* CONFIG_NUMA */
1590 * get_page_from_freelist goes through the zonelist trying to allocate
1593 static struct page *
1594 get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1595 struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
1596 struct zone *preferred_zone, int migratetype)
1599 struct page *page = NULL;
1602 nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1603 int zlc_active = 0; /* set if using zonelist_cache */
1604 int did_zlc_setup = 0; /* just call zlc_setup() one time */
1606 classzone_idx = zone_idx(preferred_zone);
1609 * Scan zonelist, looking for a zone with enough free.
1610 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1612 for_each_zone_zonelist_nodemask(zone, z, zonelist,
1613 high_zoneidx, nodemask) {
1614 if (NUMA_BUILD && zlc_active &&
1615 !zlc_zone_worth_trying(zonelist, z, allowednodes))
1617 if ((alloc_flags & ALLOC_CPUSET) &&
1618 !cpuset_zone_allowed_softwall(zone, gfp_mask))
1621 BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
1622 if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
1626 mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
1627 if (zone_watermark_ok(zone, order, mark,
1628 classzone_idx, alloc_flags))
1631 if (zone_reclaim_mode == 0)
1632 goto this_zone_full;
1634 ret = zone_reclaim(zone, gfp_mask, order);
1636 case ZONE_RECLAIM_NOSCAN:
1639 case ZONE_RECLAIM_FULL:
1640 /* scanned but unreclaimable */
1641 goto this_zone_full;
1643 /* did we reclaim enough */
1644 if (!zone_watermark_ok(zone, order, mark,
1645 classzone_idx, alloc_flags))
1646 goto this_zone_full;
1651 page = buffered_rmqueue(preferred_zone, zone, order,
1652 gfp_mask, migratetype);
1657 zlc_mark_zone_full(zonelist, z);
1659 if (NUMA_BUILD && !did_zlc_setup && nr_online_nodes > 1) {
1661 * we do zlc_setup after the first zone is tried but only
1662 * if there are multiple nodes make it worthwhile
1664 allowednodes = zlc_setup(zonelist, alloc_flags);
1670 if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
1671 /* Disable zlc cache for second zonelist scan */
1679 should_alloc_retry(gfp_t gfp_mask, unsigned int order,
1680 unsigned long pages_reclaimed)
1682 /* Do not loop if specifically requested */
1683 if (gfp_mask & __GFP_NORETRY)
1687 * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
1688 * means __GFP_NOFAIL, but that may not be true in other
1691 if (order <= PAGE_ALLOC_COSTLY_ORDER)
1695 * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
1696 * specified, then we retry until we no longer reclaim any pages
1697 * (above), or we've reclaimed an order of pages at least as
1698 * large as the allocation's order. In both cases, if the
1699 * allocation still fails, we stop retrying.
1701 if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
1705 * Don't let big-order allocations loop unless the caller
1706 * explicitly requests that.
1708 if (gfp_mask & __GFP_NOFAIL)
1714 static inline struct page *
1715 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
1716 struct zonelist *zonelist, enum zone_type high_zoneidx,
1717 nodemask_t *nodemask, struct zone *preferred_zone,
1722 /* Acquire the OOM killer lock for the zones in zonelist */
1723 if (!try_set_zone_oom(zonelist, gfp_mask)) {
1724 schedule_timeout_uninterruptible(1);
1729 * Go through the zonelist yet one more time, keep very high watermark
1730 * here, this is only to catch a parallel oom killing, we must fail if
1731 * we're still under heavy pressure.
1733 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
1734 order, zonelist, high_zoneidx,
1735 ALLOC_WMARK_HIGH|ALLOC_CPUSET,
1736 preferred_zone, migratetype);
1740 if (!(gfp_mask & __GFP_NOFAIL)) {
1741 /* The OOM killer will not help higher order allocs */
1742 if (order > PAGE_ALLOC_COSTLY_ORDER)
1745 * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
1746 * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
1747 * The caller should handle page allocation failure by itself if
1748 * it specifies __GFP_THISNODE.
1749 * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
1751 if (gfp_mask & __GFP_THISNODE)
1754 /* Exhausted what can be done so it's blamo time */
1755 out_of_memory(zonelist, gfp_mask, order, nodemask);
1758 clear_zonelist_oom(zonelist, gfp_mask);
1762 #ifdef CONFIG_COMPACTION
1763 /* Try memory compaction for high-order allocations before reclaim */
1764 static struct page *
1765 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
1766 struct zonelist *zonelist, enum zone_type high_zoneidx,
1767 nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1768 int migratetype, unsigned long *did_some_progress)
1772 if (!order || compaction_deferred(preferred_zone))
1775 *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
1777 if (*did_some_progress != COMPACT_SKIPPED) {
1779 /* Page migration frees to the PCP lists but we want merging */
1780 drain_pages(get_cpu());
1783 page = get_page_from_freelist(gfp_mask, nodemask,
1784 order, zonelist, high_zoneidx,
1785 alloc_flags, preferred_zone,
1788 preferred_zone->compact_considered = 0;
1789 preferred_zone->compact_defer_shift = 0;
1790 count_vm_event(COMPACTSUCCESS);
1795 * It's bad if compaction run occurs and fails.
1796 * The most likely reason is that pages exist,
1797 * but not enough to satisfy watermarks.
1799 count_vm_event(COMPACTFAIL);
1800 defer_compaction(preferred_zone);
1808 static inline struct page *
1809 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
1810 struct zonelist *zonelist, enum zone_type high_zoneidx,
1811 nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1812 int migratetype, unsigned long *did_some_progress)
1816 #endif /* CONFIG_COMPACTION */
1818 /* The really slow allocator path where we enter direct reclaim */
1819 static inline struct page *
1820 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
1821 struct zonelist *zonelist, enum zone_type high_zoneidx,
1822 nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1823 int migratetype, unsigned long *did_some_progress)
1825 struct page *page = NULL;
1826 struct reclaim_state reclaim_state;
1827 struct task_struct *p = current;
1831 /* We now go into synchronous reclaim */
1832 cpuset_memory_pressure_bump();
1833 p->flags |= PF_MEMALLOC;
1834 lockdep_set_current_reclaim_state(gfp_mask);
1835 reclaim_state.reclaimed_slab = 0;
1836 p->reclaim_state = &reclaim_state;
1838 *did_some_progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
1840 p->reclaim_state = NULL;
1841 lockdep_clear_current_reclaim_state();
1842 p->flags &= ~PF_MEMALLOC;
1849 if (likely(*did_some_progress))
1850 page = get_page_from_freelist(gfp_mask, nodemask, order,
1851 zonelist, high_zoneidx,
1852 alloc_flags, preferred_zone,
1858 * This is called in the allocator slow-path if the allocation request is of
1859 * sufficient urgency to ignore watermarks and take other desperate measures
1861 static inline struct page *
1862 __alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
1863 struct zonelist *zonelist, enum zone_type high_zoneidx,
1864 nodemask_t *nodemask, struct zone *preferred_zone,
1870 page = get_page_from_freelist(gfp_mask, nodemask, order,
1871 zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
1872 preferred_zone, migratetype);
1874 if (!page && gfp_mask & __GFP_NOFAIL)
1875 congestion_wait(BLK_RW_ASYNC, HZ/50);
1876 } while (!page && (gfp_mask & __GFP_NOFAIL));
1882 void wake_all_kswapd(unsigned int order, struct zonelist *zonelist,
1883 enum zone_type high_zoneidx)
1888 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
1889 wakeup_kswapd(zone, order);
1893 gfp_to_alloc_flags(gfp_t gfp_mask)
1895 struct task_struct *p = current;
1896 int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
1897 const gfp_t wait = gfp_mask & __GFP_WAIT;
1899 /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
1900 BUILD_BUG_ON(__GFP_HIGH != ALLOC_HIGH);
1903 * The caller may dip into page reserves a bit more if the caller
1904 * cannot run direct reclaim, or if the caller has realtime scheduling
1905 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
1906 * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
1908 alloc_flags |= (gfp_mask & __GFP_HIGH);
1911 alloc_flags |= ALLOC_HARDER;
1913 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
1914 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1916 alloc_flags &= ~ALLOC_CPUSET;
1917 } else if (unlikely(rt_task(p)) && !in_interrupt())
1918 alloc_flags |= ALLOC_HARDER;
1920 if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
1921 if (!in_interrupt() &&
1922 ((p->flags & PF_MEMALLOC) ||
1923 unlikely(test_thread_flag(TIF_MEMDIE))))
1924 alloc_flags |= ALLOC_NO_WATERMARKS;
1930 static inline struct page *
1931 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
1932 struct zonelist *zonelist, enum zone_type high_zoneidx,
1933 nodemask_t *nodemask, struct zone *preferred_zone,
1936 const gfp_t wait = gfp_mask & __GFP_WAIT;
1937 struct page *page = NULL;
1939 unsigned long pages_reclaimed = 0;
1940 unsigned long did_some_progress;
1941 struct task_struct *p = current;
1944 * In the slowpath, we sanity check order to avoid ever trying to
1945 * reclaim >= MAX_ORDER areas which will never succeed. Callers may
1946 * be using allocators in order of preference for an area that is
1949 if (order >= MAX_ORDER) {
1950 WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
1955 * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
1956 * __GFP_NOWARN set) should not cause reclaim since the subsystem
1957 * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
1958 * using a larger set of nodes after it has established that the
1959 * allowed per node queues are empty and that nodes are
1962 if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
1966 wake_all_kswapd(order, zonelist, high_zoneidx);
1969 * OK, we're below the kswapd watermark and have kicked background
1970 * reclaim. Now things get more complex, so set up alloc_flags according
1971 * to how we want to proceed.
1973 alloc_flags = gfp_to_alloc_flags(gfp_mask);
1975 /* This is the last chance, in general, before the goto nopage. */
1976 page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
1977 high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
1978 preferred_zone, migratetype);
1983 /* Allocate without watermarks if the context allows */
1984 if (alloc_flags & ALLOC_NO_WATERMARKS) {
1985 page = __alloc_pages_high_priority(gfp_mask, order,
1986 zonelist, high_zoneidx, nodemask,
1987 preferred_zone, migratetype);
1992 /* Atomic allocations - we can't balance anything */
1996 /* Avoid recursion of direct reclaim */
1997 if (p->flags & PF_MEMALLOC)
2000 /* Avoid allocations with no watermarks from looping endlessly */
2001 if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
2004 /* Try direct compaction */
2005 page = __alloc_pages_direct_compact(gfp_mask, order,
2006 zonelist, high_zoneidx,
2008 alloc_flags, preferred_zone,
2009 migratetype, &did_some_progress);
2013 /* Try direct reclaim and then allocating */
2014 page = __alloc_pages_direct_reclaim(gfp_mask, order,
2015 zonelist, high_zoneidx,
2017 alloc_flags, preferred_zone,
2018 migratetype, &did_some_progress);
2023 * If we failed to make any progress reclaiming, then we are
2024 * running out of options and have to consider going OOM
2026 if (!did_some_progress) {
2027 if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
2028 if (oom_killer_disabled)
2030 page = __alloc_pages_may_oom(gfp_mask, order,
2031 zonelist, high_zoneidx,
2032 nodemask, preferred_zone,
2038 * The OOM killer does not trigger for high-order
2039 * ~__GFP_NOFAIL allocations so if no progress is being
2040 * made, there are no other options and retrying is
2043 if (order > PAGE_ALLOC_COSTLY_ORDER &&
2044 !(gfp_mask & __GFP_NOFAIL))
2051 /* Check if we should retry the allocation */
2052 pages_reclaimed += did_some_progress;
2053 if (should_alloc_retry(gfp_mask, order, pages_reclaimed)) {
2054 /* Wait for some write requests to complete then retry */
2055 congestion_wait(BLK_RW_ASYNC, HZ/50);
2060 if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
2061 printk(KERN_WARNING "%s: page allocation failure."
2062 " order:%d, mode:0x%x\n",
2063 p->comm, order, gfp_mask);
2069 if (kmemcheck_enabled)
2070 kmemcheck_pagealloc_alloc(page, order, gfp_mask);
2076 * This is the 'heart' of the zoned buddy allocator.
2079 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
2080 struct zonelist *zonelist, nodemask_t *nodemask)
2082 enum zone_type high_zoneidx = gfp_zone(gfp_mask);
2083 struct zone *preferred_zone;
2085 int migratetype = allocflags_to_migratetype(gfp_mask);
2087 gfp_mask &= gfp_allowed_mask;
2089 lockdep_trace_alloc(gfp_mask);
2091 might_sleep_if(gfp_mask & __GFP_WAIT);
2093 if (should_fail_alloc_page(gfp_mask, order))
2097 * Check the zones suitable for the gfp_mask contain at least one
2098 * valid zone. It's possible to have an empty zonelist as a result
2099 * of GFP_THISNODE and a memoryless node
2101 if (unlikely(!zonelist->_zonerefs->zone))
2105 /* The preferred zone is used for statistics later */
2106 first_zones_zonelist(zonelist, high_zoneidx, nodemask, &preferred_zone);
2107 if (!preferred_zone) {
2112 /* First allocation attempt */
2113 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
2114 zonelist, high_zoneidx, ALLOC_WMARK_LOW|ALLOC_CPUSET,
2115 preferred_zone, migratetype);
2116 if (unlikely(!page))
2117 page = __alloc_pages_slowpath(gfp_mask, order,
2118 zonelist, high_zoneidx, nodemask,
2119 preferred_zone, migratetype);
2122 trace_mm_page_alloc(page, order, gfp_mask, migratetype);
2125 EXPORT_SYMBOL(__alloc_pages_nodemask);
2128 * Common helper functions.
2130 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
2135 * __get_free_pages() returns a 32-bit address, which cannot represent
2138 VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
2140 page = alloc_pages(gfp_mask, order);
2143 return (unsigned long) page_address(page);
2145 EXPORT_SYMBOL(__get_free_pages);
2147 unsigned long get_zeroed_page(gfp_t gfp_mask)
2149 return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
2151 EXPORT_SYMBOL(get_zeroed_page);
2153 void __pagevec_free(struct pagevec *pvec)
2155 int i = pagevec_count(pvec);
2158 trace_mm_pagevec_free(pvec->pages[i], pvec->cold);
2159 free_hot_cold_page(pvec->pages[i], pvec->cold);
2163 void __free_pages(struct page *page, unsigned int order)
2165 if (put_page_testzero(page)) {
2167 free_hot_cold_page(page, 0);
2169 __free_pages_ok(page, order);
2173 EXPORT_SYMBOL(__free_pages);
2175 void free_pages(unsigned long addr, unsigned int order)
2178 VM_BUG_ON(!virt_addr_valid((void *)addr));
2179 __free_pages(virt_to_page((void *)addr), order);
2183 EXPORT_SYMBOL(free_pages);
2186 * alloc_pages_exact - allocate an exact number physically-contiguous pages.
2187 * @size: the number of bytes to allocate
2188 * @gfp_mask: GFP flags for the allocation
2190 * This function is similar to alloc_pages(), except that it allocates the
2191 * minimum number of pages to satisfy the request. alloc_pages() can only
2192 * allocate memory in power-of-two pages.
2194 * This function is also limited by MAX_ORDER.
2196 * Memory allocated by this function must be released by free_pages_exact().
2198 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
2200 unsigned int order = get_order(size);
2203 addr = __get_free_pages(gfp_mask, order);
2205 unsigned long alloc_end = addr + (PAGE_SIZE << order);
2206 unsigned long used = addr + PAGE_ALIGN(size);
2208 split_page(virt_to_page((void *)addr), order);
2209 while (used < alloc_end) {
2215 return (void *)addr;
2217 EXPORT_SYMBOL(alloc_pages_exact);
2220 * free_pages_exact - release memory allocated via alloc_pages_exact()
2221 * @virt: the value returned by alloc_pages_exact.
2222 * @size: size of allocation, same value as passed to alloc_pages_exact().
2224 * Release the memory allocated by a previous call to alloc_pages_exact.
2226 void free_pages_exact(void *virt, size_t size)
2228 unsigned long addr = (unsigned long)virt;
2229 unsigned long end = addr + PAGE_ALIGN(size);
2231 while (addr < end) {
2236 EXPORT_SYMBOL(free_pages_exact);
2238 static unsigned int nr_free_zone_pages(int offset)
2243 /* Just pick one node, since fallback list is circular */
2244 unsigned int sum = 0;
2246 struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
2248 for_each_zone_zonelist(zone, z, zonelist, offset) {
2249 unsigned long size = zone->present_pages;
2250 unsigned long high = high_wmark_pages(zone);
2259 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
2261 unsigned int nr_free_buffer_pages(void)
2263 return nr_free_zone_pages(gfp_zone(GFP_USER));
2265 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
2268 * Amount of free RAM allocatable within all zones
2270 unsigned int nr_free_pagecache_pages(void)
2272 return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
2275 static inline void show_node(struct zone *zone)
2278 printk("Node %d ", zone_to_nid(zone));
2281 void si_meminfo(struct sysinfo *val)
2283 val->totalram = totalram_pages;
2285 val->freeram = global_page_state(NR_FREE_PAGES);
2286 val->bufferram = nr_blockdev_pages();
2287 val->totalhigh = totalhigh_pages;
2288 val->freehigh = nr_free_highpages();
2289 val->mem_unit = PAGE_SIZE;
2292 EXPORT_SYMBOL(si_meminfo);
2295 void si_meminfo_node(struct sysinfo *val, int nid)
2297 pg_data_t *pgdat = NODE_DATA(nid);
2299 val->totalram = pgdat->node_present_pages;
2300 val->freeram = node_page_state(nid, NR_FREE_PAGES);
2301 #ifdef CONFIG_HIGHMEM
2302 val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
2303 val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
2309 val->mem_unit = PAGE_SIZE;
2313 #define K(x) ((x) << (PAGE_SHIFT-10))
2316 * Show free area list (used inside shift_scroll-lock stuff)
2317 * We also calculate the percentage fragmentation. We do this by counting the
2318 * memory on each free list with the exception of the first item on the list.
2320 void show_free_areas(void)
2325 for_each_populated_zone(zone) {
2327 printk("%s per-cpu:\n", zone->name);
2329 for_each_online_cpu(cpu) {
2330 struct per_cpu_pageset *pageset;
2332 pageset = per_cpu_ptr(zone->pageset, cpu);
2334 printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
2335 cpu, pageset->pcp.high,
2336 pageset->pcp.batch, pageset->pcp.count);
2340 printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
2341 " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
2343 " dirty:%lu writeback:%lu unstable:%lu\n"
2344 " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
2345 " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n",
2346 global_page_state(NR_ACTIVE_ANON),
2347 global_page_state(NR_INACTIVE_ANON),
2348 global_page_state(NR_ISOLATED_ANON),
2349 global_page_state(NR_ACTIVE_FILE),
2350 global_page_state(NR_INACTIVE_FILE),
2351 global_page_state(NR_ISOLATED_FILE),
2352 global_page_state(NR_UNEVICTABLE),
2353 global_page_state(NR_FILE_DIRTY),
2354 global_page_state(NR_WRITEBACK),
2355 global_page_state(NR_UNSTABLE_NFS),
2356 global_page_state(NR_FREE_PAGES),
2357 global_page_state(NR_SLAB_RECLAIMABLE),
2358 global_page_state(NR_SLAB_UNRECLAIMABLE),
2359 global_page_state(NR_FILE_MAPPED),
2360 global_page_state(NR_SHMEM),
2361 global_page_state(NR_PAGETABLE),
2362 global_page_state(NR_BOUNCE));
2364 for_each_populated_zone(zone) {
2373 " active_anon:%lukB"
2374 " inactive_anon:%lukB"
2375 " active_file:%lukB"
2376 " inactive_file:%lukB"
2377 " unevictable:%lukB"
2378 " isolated(anon):%lukB"
2379 " isolated(file):%lukB"
2386 " slab_reclaimable:%lukB"
2387 " slab_unreclaimable:%lukB"
2388 " kernel_stack:%lukB"
2392 " writeback_tmp:%lukB"
2393 " pages_scanned:%lu"
2394 " all_unreclaimable? %s"
2397 K(zone_page_state(zone, NR_FREE_PAGES)),
2398 K(min_wmark_pages(zone)),
2399 K(low_wmark_pages(zone)),
2400 K(high_wmark_pages(zone)),
2401 K(zone_page_state(zone, NR_ACTIVE_ANON)),
2402 K(zone_page_state(zone, NR_INACTIVE_ANON)),
2403 K(zone_page_state(zone, NR_ACTIVE_FILE)),
2404 K(zone_page_state(zone, NR_INACTIVE_FILE)),
2405 K(zone_page_state(zone, NR_UNEVICTABLE)),
2406 K(zone_page_state(zone, NR_ISOLATED_ANON)),
2407 K(zone_page_state(zone, NR_ISOLATED_FILE)),
2408 K(zone->present_pages),
2409 K(zone_page_state(zone, NR_MLOCK)),
2410 K(zone_page_state(zone, NR_FILE_DIRTY)),
2411 K(zone_page_state(zone, NR_WRITEBACK)),
2412 K(zone_page_state(zone, NR_FILE_MAPPED)),
2413 K(zone_page_state(zone, NR_SHMEM)),
2414 K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
2415 K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
2416 zone_page_state(zone, NR_KERNEL_STACK) *
2418 K(zone_page_state(zone, NR_PAGETABLE)),
2419 K(zone_page_state(zone, NR_UNSTABLE_NFS)),
2420 K(zone_page_state(zone, NR_BOUNCE)),
2421 K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
2422 zone->pages_scanned,
2423 (zone->all_unreclaimable ? "yes" : "no")
2425 printk("lowmem_reserve[]:");
2426 for (i = 0; i < MAX_NR_ZONES; i++)
2427 printk(" %lu", zone->lowmem_reserve[i]);
2431 for_each_populated_zone(zone) {
2432 unsigned long nr[MAX_ORDER], flags, order, total = 0;
2435 printk("%s: ", zone->name);
2437 spin_lock_irqsave(&zone->lock, flags);
2438 for (order = 0; order < MAX_ORDER; order++) {
2439 nr[order] = zone->free_area[order].nr_free;
2440 total += nr[order] << order;
2442 spin_unlock_irqrestore(&zone->lock, flags);
2443 for (order = 0; order < MAX_ORDER; order++)
2444 printk("%lu*%lukB ", nr[order], K(1UL) << order);
2445 printk("= %lukB\n", K(total));
2448 printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
2450 show_swap_cache_info();
2453 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
2455 zoneref->zone = zone;
2456 zoneref->zone_idx = zone_idx(zone);
2460 * Builds allocation fallback zone lists.
2462 * Add all populated zones of a node to the zonelist.
2464 static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
2465 int nr_zones, enum zone_type zone_type)
2469 BUG_ON(zone_type >= MAX_NR_ZONES);
2474 zone = pgdat->node_zones + zone_type;
2475 if (populated_zone(zone)) {
2476 zoneref_set_zone(zone,
2477 &zonelist->_zonerefs[nr_zones++]);
2478 check_highest_zone(zone_type);
2481 } while (zone_type);
2488 * 0 = automatic detection of better ordering.
2489 * 1 = order by ([node] distance, -zonetype)
2490 * 2 = order by (-zonetype, [node] distance)
2492 * If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
2493 * the same zonelist. So only NUMA can configure this param.
2495 #define ZONELIST_ORDER_DEFAULT 0
2496 #define ZONELIST_ORDER_NODE 1
2497 #define ZONELIST_ORDER_ZONE 2
2499 /* zonelist order in the kernel.
2500 * set_zonelist_order() will set this to NODE or ZONE.
2502 static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
2503 static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
2507 /* The value user specified ....changed by config */
2508 static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2509 /* string for sysctl */
2510 #define NUMA_ZONELIST_ORDER_LEN 16
2511 char numa_zonelist_order[16] = "default";
2514 * interface for configure zonelist ordering.
2515 * command line option "numa_zonelist_order"
2516 * = "[dD]efault - default, automatic configuration.
2517 * = "[nN]ode - order by node locality, then by zone within node
2518 * = "[zZ]one - order by zone, then by locality within zone
2521 static int __parse_numa_zonelist_order(char *s)
2523 if (*s == 'd' || *s == 'D') {
2524 user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2525 } else if (*s == 'n' || *s == 'N') {
2526 user_zonelist_order = ZONELIST_ORDER_NODE;
2527 } else if (*s == 'z' || *s == 'Z') {
2528 user_zonelist_order = ZONELIST_ORDER_ZONE;
2531 "Ignoring invalid numa_zonelist_order value: "
2538 static __init int setup_numa_zonelist_order(char *s)
2541 return __parse_numa_zonelist_order(s);
2544 early_param("numa_zonelist_order", setup_numa_zonelist_order);
2547 * sysctl handler for numa_zonelist_order
2549 int numa_zonelist_order_handler(ctl_table *table, int write,
2550 void __user *buffer, size_t *length,
2553 char saved_string[NUMA_ZONELIST_ORDER_LEN];
2555 static DEFINE_MUTEX(zl_order_mutex);
2557 mutex_lock(&zl_order_mutex);
2559 strcpy(saved_string, (char*)table->data);
2560 ret = proc_dostring(table, write, buffer, length, ppos);
2564 int oldval = user_zonelist_order;
2565 if (__parse_numa_zonelist_order((char*)table->data)) {
2567 * bogus value. restore saved string
2569 strncpy((char*)table->data, saved_string,
2570 NUMA_ZONELIST_ORDER_LEN);
2571 user_zonelist_order = oldval;
2572 } else if (oldval != user_zonelist_order)
2573 build_all_zonelists();
2576 mutex_unlock(&zl_order_mutex);
2581 #define MAX_NODE_LOAD (nr_online_nodes)
2582 static int node_load[MAX_NUMNODES];
2585 * find_next_best_node - find the next node that should appear in a given node's fallback list
2586 * @node: node whose fallback list we're appending
2587 * @used_node_mask: nodemask_t of already used nodes
2589 * We use a number of factors to determine which is the next node that should
2590 * appear on a given node's fallback list. The node should not have appeared
2591 * already in @node's fallback list, and it should be the next closest node
2592 * according to the distance array (which contains arbitrary distance values
2593 * from each node to each node in the system), and should also prefer nodes
2594 * with no CPUs, since presumably they'll have very little allocation pressure
2595 * on them otherwise.
2596 * It returns -1 if no node is found.
2598 static int find_next_best_node(int node, nodemask_t *used_node_mask)
2601 int min_val = INT_MAX;
2603 const struct cpumask *tmp = cpumask_of_node(0);
2605 /* Use the local node if we haven't already */
2606 if (!node_isset(node, *used_node_mask)) {
2607 node_set(node, *used_node_mask);
2611 for_each_node_state(n, N_HIGH_MEMORY) {
2613 /* Don't want a node to appear more than once */
2614 if (node_isset(n, *used_node_mask))
2617 /* Use the distance array to find the distance */
2618 val = node_distance(node, n);
2620 /* Penalize nodes under us ("prefer the next node") */
2623 /* Give preference to headless and unused nodes */
2624 tmp = cpumask_of_node(n);
2625 if (!cpumask_empty(tmp))
2626 val += PENALTY_FOR_NODE_WITH_CPUS;
2628 /* Slight preference for less loaded node */
2629 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
2630 val += node_load[n];
2632 if (val < min_val) {
2639 node_set(best_node, *used_node_mask);
2646 * Build zonelists ordered by node and zones within node.
2647 * This results in maximum locality--normal zone overflows into local
2648 * DMA zone, if any--but risks exhausting DMA zone.
2650 static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
2653 struct zonelist *zonelist;
2655 zonelist = &pgdat->node_zonelists[0];
2656 for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
2658 j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2660 zonelist->_zonerefs[j].zone = NULL;
2661 zonelist->_zonerefs[j].zone_idx = 0;
2665 * Build gfp_thisnode zonelists
2667 static void build_thisnode_zonelists(pg_data_t *pgdat)
2670 struct zonelist *zonelist;
2672 zonelist = &pgdat->node_zonelists[1];
2673 j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
2674 zonelist->_zonerefs[j].zone = NULL;
2675 zonelist->_zonerefs[j].zone_idx = 0;
2679 * Build zonelists ordered by zone and nodes within zones.
2680 * This results in conserving DMA zone[s] until all Normal memory is
2681 * exhausted, but results in overflowing to remote node while memory
2682 * may still exist in local DMA zone.
2684 static int node_order[MAX_NUMNODES];
2686 static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
2689 int zone_type; /* needs to be signed */
2691 struct zonelist *zonelist;
2693 zonelist = &pgdat->node_zonelists[0];
2695 for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
2696 for (j = 0; j < nr_nodes; j++) {
2697 node = node_order[j];
2698 z = &NODE_DATA(node)->node_zones[zone_type];
2699 if (populated_zone(z)) {
2701 &zonelist->_zonerefs[pos++]);
2702 check_highest_zone(zone_type);
2706 zonelist->_zonerefs[pos].zone = NULL;
2707 zonelist->_zonerefs[pos].zone_idx = 0;
2710 static int default_zonelist_order(void)
2713 unsigned long low_kmem_size,total_size;
2717 * ZONE_DMA and ZONE_DMA32 can be very small area in the system.
2718 * If they are really small and used heavily, the system can fall
2719 * into OOM very easily.
2720 * This function detect ZONE_DMA/DMA32 size and configures zone order.
2722 /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
2725 for_each_online_node(nid) {
2726 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
2727 z = &NODE_DATA(nid)->node_zones[zone_type];
2728 if (populated_zone(z)) {
2729 if (zone_type < ZONE_NORMAL)
2730 low_kmem_size += z->present_pages;
2731 total_size += z->present_pages;
2732 } else if (zone_type == ZONE_NORMAL) {
2734 * If any node has only lowmem, then node order
2735 * is preferred to allow kernel allocations
2736 * locally; otherwise, they can easily infringe
2737 * on other nodes when there is an abundance of
2738 * lowmem available to allocate from.
2740 return ZONELIST_ORDER_NODE;
2744 if (!low_kmem_size || /* there are no DMA area. */
2745 low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
2746 return ZONELIST_ORDER_NODE;
2748 * look into each node's config.
2749 * If there is a node whose DMA/DMA32 memory is very big area on
2750 * local memory, NODE_ORDER may be suitable.
2752 average_size = total_size /
2753 (nodes_weight(node_states[N_HIGH_MEMORY]) + 1);
2754 for_each_online_node(nid) {
2757 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
2758 z = &NODE_DATA(nid)->node_zones[zone_type];
2759 if (populated_zone(z)) {
2760 if (zone_type < ZONE_NORMAL)
2761 low_kmem_size += z->present_pages;
2762 total_size += z->present_pages;
2765 if (low_kmem_size &&
2766 total_size > average_size && /* ignore small node */
2767 low_kmem_size > total_size * 70/100)
2768 return ZONELIST_ORDER_NODE;
2770 return ZONELIST_ORDER_ZONE;
2773 static void set_zonelist_order(void)
2775 if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
2776 current_zonelist_order = default_zonelist_order();
2778 current_zonelist_order = user_zonelist_order;
2781 static void build_zonelists(pg_data_t *pgdat)
2785 nodemask_t used_mask;
2786 int local_node, prev_node;
2787 struct zonelist *zonelist;
2788 int order = current_zonelist_order;
2790 /* initialize zonelists */
2791 for (i = 0; i < MAX_ZONELISTS; i++) {
2792 zonelist = pgdat->node_zonelists + i;
2793 zonelist->_zonerefs[0].zone = NULL;
2794 zonelist->_zonerefs[0].zone_idx = 0;
2797 /* NUMA-aware ordering of nodes */
2798 local_node = pgdat->node_id;
2799 load = nr_online_nodes;
2800 prev_node = local_node;
2801 nodes_clear(used_mask);
2803 memset(node_order, 0, sizeof(node_order));
2806 while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
2807 int distance = node_distance(local_node, node);
2810 * If another node is sufficiently far away then it is better
2811 * to reclaim pages in a zone before going off node.
2813 if (distance > RECLAIM_DISTANCE)
2814 zone_reclaim_mode = 1;
2817 * We don't want to pressure a particular node.
2818 * So adding penalty to the first node in same
2819 * distance group to make it round-robin.
2821 if (distance != node_distance(local_node, prev_node))
2822 node_load[node] = load;
2826 if (order == ZONELIST_ORDER_NODE)
2827 build_zonelists_in_node_order(pgdat, node);
2829 node_order[j++] = node; /* remember order */
2832 if (order == ZONELIST_ORDER_ZONE) {
2833 /* calculate node order -- i.e., DMA last! */
2834 build_zonelists_in_zone_order(pgdat, j);
2837 build_thisnode_zonelists(pgdat);
2840 /* Construct the zonelist performance cache - see further mmzone.h */
2841 static void build_zonelist_cache(pg_data_t *pgdat)
2843 struct zonelist *zonelist;
2844 struct zonelist_cache *zlc;
2847 zonelist = &pgdat->node_zonelists[0];
2848 zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
2849 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
2850 for (z = zonelist->_zonerefs; z->zone; z++)
2851 zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
2855 #else /* CONFIG_NUMA */
2857 static void set_zonelist_order(void)
2859 current_zonelist_order = ZONELIST_ORDER_ZONE;
2862 static void build_zonelists(pg_data_t *pgdat)
2864 int node, local_node;
2866 struct zonelist *zonelist;
2868 local_node = pgdat->node_id;
2870 zonelist = &pgdat->node_zonelists[0];
2871 j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
2874 * Now we build the zonelist so that it contains the zones
2875 * of all the other nodes.
2876 * We don't want to pressure a particular node, so when
2877 * building the zones for node N, we make sure that the
2878 * zones coming right after the local ones are those from
2879 * node N+1 (modulo N)
2881 for (node = local_node + 1; node < MAX_NUMNODES; node++) {
2882 if (!node_online(node))
2884 j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2887 for (node = 0; node < local_node; node++) {
2888 if (!node_online(node))
2890 j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2894 zonelist->_zonerefs[j].zone = NULL;
2895 zonelist->_zonerefs[j].zone_idx = 0;
2898 /* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
2899 static void build_zonelist_cache(pg_data_t *pgdat)
2901 pgdat->node_zonelists[0].zlcache_ptr = NULL;
2904 #endif /* CONFIG_NUMA */
2907 * Boot pageset table. One per cpu which is going to be used for all
2908 * zones and all nodes. The parameters will be set in such a way
2909 * that an item put on a list will immediately be handed over to
2910 * the buddy list. This is safe since pageset manipulation is done
2911 * with interrupts disabled.
2913 * The boot_pagesets must be kept even after bootup is complete for
2914 * unused processors and/or zones. They do play a role for bootstrapping
2915 * hotplugged processors.
2917 * zoneinfo_show() and maybe other functions do
2918 * not check if the processor is online before following the pageset pointer.
2919 * Other parts of the kernel may not check if the zone is available.
2921 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
2922 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
2924 /* return values int ....just for stop_machine() */
2925 static int __build_all_zonelists(void *dummy)
2931 memset(node_load, 0, sizeof(node_load));
2933 for_each_online_node(nid) {
2934 pg_data_t *pgdat = NODE_DATA(nid);
2936 build_zonelists(pgdat);
2937 build_zonelist_cache(pgdat);
2941 * Initialize the boot_pagesets that are going to be used
2942 * for bootstrapping processors. The real pagesets for
2943 * each zone will be allocated later when the per cpu
2944 * allocator is available.
2946 * boot_pagesets are used also for bootstrapping offline
2947 * cpus if the system is already booted because the pagesets
2948 * are needed to initialize allocators on a specific cpu too.
2949 * F.e. the percpu allocator needs the page allocator which
2950 * needs the percpu allocator in order to allocate its pagesets
2951 * (a chicken-egg dilemma).
2953 for_each_possible_cpu(cpu)
2954 setup_pageset(&per_cpu(boot_pageset, cpu), 0);
2959 void build_all_zonelists(void)
2961 set_zonelist_order();
2963 if (system_state == SYSTEM_BOOTING) {
2964 __build_all_zonelists(NULL);
2965 mminit_verify_zonelist();
2966 cpuset_init_current_mems_allowed();
2968 /* we have to stop all cpus to guarantee there is no user
2970 stop_machine(__build_all_zonelists, NULL, NULL);
2971 /* cpuset refresh routine should be here */
2973 vm_total_pages = nr_free_pagecache_pages();
2975 * Disable grouping by mobility if the number of pages in the
2976 * system is too low to allow the mechanism to work. It would be
2977 * more accurate, but expensive to check per-zone. This check is
2978 * made on memory-hotadd so a system can start with mobility
2979 * disabled and enable it later
2981 if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
2982 page_group_by_mobility_disabled = 1;
2984 page_group_by_mobility_disabled = 0;
2986 printk("Built %i zonelists in %s order, mobility grouping %s. "
2987 "Total pages: %ld\n",
2989 zonelist_order_name[current_zonelist_order],
2990 page_group_by_mobility_disabled ? "off" : "on",
2993 printk("Policy zone: %s\n", zone_names[policy_zone]);
2998 * Helper functions to size the waitqueue hash table.
2999 * Essentially these want to choose hash table sizes sufficiently
3000 * large so that collisions trying to wait on pages are rare.
3001 * But in fact, the number of active page waitqueues on typical
3002 * systems is ridiculously low, less than 200. So this is even
3003 * conservative, even though it seems large.
3005 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
3006 * waitqueues, i.e. the size of the waitq table given the number of pages.
3008 #define PAGES_PER_WAITQUEUE 256
3010 #ifndef CONFIG_MEMORY_HOTPLUG
3011 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3013 unsigned long size = 1;
3015 pages /= PAGES_PER_WAITQUEUE;
3017 while (size < pages)
3021 * Once we have dozens or even hundreds of threads sleeping
3022 * on IO we've got bigger problems than wait queue collision.
3023 * Limit the size of the wait table to a reasonable size.
3025 size = min(size, 4096UL);
3027 return max(size, 4UL);
3031 * A zone's size might be changed by hot-add, so it is not possible to determine
3032 * a suitable size for its wait_table. So we use the maximum size now.
3034 * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie:
3036 * i386 (preemption config) : 4096 x 16 = 64Kbyte.
3037 * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
3038 * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte.
3040 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
3041 * or more by the traditional way. (See above). It equals:
3043 * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte.
3044 * ia64(16K page size) : = ( 8G + 4M)byte.
3045 * powerpc (64K page size) : = (32G +16M)byte.
3047 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3054 * This is an integer logarithm so that shifts can be used later
3055 * to extract the more random high bits from the multiplicative
3056 * hash function before the remainder is taken.
3058 static inline unsigned long wait_table_bits(unsigned long size)
3063 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
3066 * Mark a number of pageblocks as MIGRATE_RESERVE. The number
3067 * of blocks reserved is based on min_wmark_pages(zone). The memory within
3068 * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
3069 * higher will lead to a bigger reserve which will get freed as contiguous
3070 * blocks as reclaim kicks in
3072 static void setup_zone_migrate_reserve(struct zone *zone)
3074 unsigned long start_pfn, pfn, end_pfn;
3076 unsigned long block_migratetype;
3079 /* Get the start pfn, end pfn and the number of blocks to reserve */
3080 start_pfn = zone->zone_start_pfn;
3081 end_pfn = start_pfn + zone->spanned_pages;
3082 reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
3086 * Reserve blocks are generally in place to help high-order atomic
3087 * allocations that are short-lived. A min_free_kbytes value that
3088 * would result in more than 2 reserve blocks for atomic allocations
3089 * is assumed to be in place to help anti-fragmentation for the
3090 * future allocation of hugepages at runtime.
3092 reserve = min(2, reserve);
3094 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
3095 if (!pfn_valid(pfn))
3097 page = pfn_to_page(pfn);
3099 /* Watch out for overlapping nodes */
3100 if (page_to_nid(page) != zone_to_nid(zone))
3103 /* Blocks with reserved pages will never free, skip them. */
3104 if (PageReserved(page))
3107 block_migratetype = get_pageblock_migratetype(page);
3109 /* If this block is reserved, account for it */
3110 if (reserve > 0 && block_migratetype == MIGRATE_RESERVE) {
3115 /* Suitable for reserving if this block is movable */
3116 if (reserve > 0 && block_migratetype == MIGRATE_MOVABLE) {
3117 set_pageblock_migratetype(page, MIGRATE_RESERVE);
3118 move_freepages_block(zone, page, MIGRATE_RESERVE);
3124 * If the reserve is met and this is a previous reserved block,
3127 if (block_migratetype == MIGRATE_RESERVE) {
3128 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3129 move_freepages_block(zone, page, MIGRATE_MOVABLE);
3135 * Initially all pages are reserved - free ones are freed
3136 * up by free_all_bootmem() once the early boot process is
3137 * done. Non-atomic initialization, single-pass.
3139 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
3140 unsigned long start_pfn, enum memmap_context context)
3143 unsigned long end_pfn = start_pfn + size;
3147 if (highest_memmap_pfn < end_pfn - 1)
3148 highest_memmap_pfn = end_pfn - 1;
3150 z = &NODE_DATA(nid)->node_zones[zone];
3151 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3153 * There can be holes in boot-time mem_map[]s
3154 * handed to this function. They do not
3155 * exist on hotplugged memory.
3157 if (context == MEMMAP_EARLY) {
3158 if (!early_pfn_valid(pfn))
3160 if (!early_pfn_in_nid(pfn, nid))
3163 page = pfn_to_page(pfn);
3164 set_page_links(page, zone, nid, pfn);
3165 mminit_verify_page_links(page, zone, nid, pfn);
3166 init_page_count(page);
3167 reset_page_mapcount(page);
3168 SetPageReserved(page);
3170 * Mark the block movable so that blocks are reserved for
3171 * movable at startup. This will force kernel allocations
3172 * to reserve their blocks rather than leaking throughout
3173 * the address space during boot when many long-lived
3174 * kernel allocations are made. Later some blocks near
3175 * the start are marked MIGRATE_RESERVE by
3176 * setup_zone_migrate_reserve()
3178 * bitmap is created for zone's valid pfn range. but memmap
3179 * can be created for invalid pages (for alignment)
3180 * check here not to call set_pageblock_migratetype() against
3183 if ((z->zone_start_pfn <= pfn)
3184 && (pfn < z->zone_start_pfn + z->spanned_pages)
3185 && !(pfn & (pageblock_nr_pages - 1)))
3186 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3188 INIT_LIST_HEAD(&page->lru);
3189 #ifdef WANT_PAGE_VIRTUAL
3190 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
3191 if (!is_highmem_idx(zone))
3192 set_page_address(page, __va(pfn << PAGE_SHIFT));
3197 static void __meminit zone_init_free_lists(struct zone *zone)
3200 for_each_migratetype_order(order, t) {
3201 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
3202 zone->free_area[order].nr_free = 0;
3206 #ifndef __HAVE_ARCH_MEMMAP_INIT
3207 #define memmap_init(size, nid, zone, start_pfn) \
3208 memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
3211 static int zone_batchsize(struct zone *zone)
3217 * The per-cpu-pages pools are set to around 1000th of the
3218 * size of the zone. But no more than 1/2 of a meg.
3220 * OK, so we don't know how big the cache is. So guess.
3222 batch = zone->present_pages / 1024;
3223 if (batch * PAGE_SIZE > 512 * 1024)
3224 batch = (512 * 1024) / PAGE_SIZE;
3225 batch /= 4; /* We effectively *= 4 below */
3230 * Clamp the batch to a 2^n - 1 value. Having a power
3231 * of 2 value was found to be more likely to have
3232 * suboptimal cache aliasing properties in some cases.
3234 * For example if 2 tasks are alternately allocating
3235 * batches of pages, one task can end up with a lot
3236 * of pages of one half of the possible page colors
3237 * and the other with pages of the other colors.
3239 batch = rounddown_pow_of_two(batch + batch/2) - 1;
3244 /* The deferral and batching of frees should be suppressed under NOMMU
3247 * The problem is that NOMMU needs to be able to allocate large chunks
3248 * of contiguous memory as there's no hardware page translation to
3249 * assemble apparent contiguous memory from discontiguous pages.
3251 * Queueing large contiguous runs of pages for batching, however,
3252 * causes the pages to actually be freed in smaller chunks. As there
3253 * can be a significant delay between the individual batches being
3254 * recycled, this leads to the once large chunks of space being
3255 * fragmented and becoming unavailable for high-order allocations.
3261 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
3263 struct per_cpu_pages *pcp;
3266 memset(p, 0, sizeof(*p));
3270 pcp->high = 6 * batch;
3271 pcp->batch = max(1UL, 1 * batch);
3272 for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
3273 INIT_LIST_HEAD(&pcp->lists[migratetype]);
3277 * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
3278 * to the value high for the pageset p.
3281 static void setup_pagelist_highmark(struct per_cpu_pageset *p,
3284 struct per_cpu_pages *pcp;
3288 pcp->batch = max(1UL, high/4);
3289 if ((high/4) > (PAGE_SHIFT * 8))
3290 pcp->batch = PAGE_SHIFT * 8;
3294 * Allocate per cpu pagesets and initialize them.
3295 * Before this call only boot pagesets were available.
3296 * Boot pagesets will no longer be used by this processorr
3297 * after setup_per_cpu_pageset().
3299 void __init setup_per_cpu_pageset(void)
3304 for_each_populated_zone(zone) {
3305 zone->pageset = alloc_percpu(struct per_cpu_pageset);
3307 for_each_possible_cpu(cpu) {
3308 struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
3310 setup_pageset(pcp, zone_batchsize(zone));
3312 if (percpu_pagelist_fraction)
3313 setup_pagelist_highmark(pcp,
3314 (zone->present_pages /
3315 percpu_pagelist_fraction));
3320 static noinline __init_refok
3321 int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
3324 struct pglist_data *pgdat = zone->zone_pgdat;
3328 * The per-page waitqueue mechanism uses hashed waitqueues
3331 zone->wait_table_hash_nr_entries =
3332 wait_table_hash_nr_entries(zone_size_pages);
3333 zone->wait_table_bits =
3334 wait_table_bits(zone->wait_table_hash_nr_entries);
3335 alloc_size = zone->wait_table_hash_nr_entries
3336 * sizeof(wait_queue_head_t);
3338 if (!slab_is_available()) {
3339 zone->wait_table = (wait_queue_head_t *)
3340 alloc_bootmem_node(pgdat, alloc_size);
3343 * This case means that a zone whose size was 0 gets new memory
3344 * via memory hot-add.
3345 * But it may be the case that a new node was hot-added. In
3346 * this case vmalloc() will not be able to use this new node's
3347 * memory - this wait_table must be initialized to use this new
3348 * node itself as well.
3349 * To use this new node's memory, further consideration will be
3352 zone->wait_table = vmalloc(alloc_size);
3354 if (!zone->wait_table)
3357 for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
3358 init_waitqueue_head(zone->wait_table + i);
3363 static int __zone_pcp_update(void *data)
3365 struct zone *zone = data;
3367 unsigned long batch = zone_batchsize(zone), flags;
3369 for_each_possible_cpu(cpu) {
3370 struct per_cpu_pageset *pset;
3371 struct per_cpu_pages *pcp;
3373 pset = per_cpu_ptr(zone->pageset, cpu);
3376 local_irq_save(flags);
3377 free_pcppages_bulk(zone, pcp->count, pcp);
3378 setup_pageset(pset, batch);
3379 local_irq_restore(flags);
3384 void zone_pcp_update(struct zone *zone)
3386 stop_machine(__zone_pcp_update, zone, NULL);
3389 static __meminit void zone_pcp_init(struct zone *zone)
3392 * per cpu subsystem is not up at this point. The following code
3393 * relies on the ability of the linker to provide the
3394 * offset of a (static) per cpu variable into the per cpu area.
3396 zone->pageset = &boot_pageset;
3398 if (zone->present_pages)
3399 printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n",
3400 zone->name, zone->present_pages,
3401 zone_batchsize(zone));
3404 __meminit int init_currently_empty_zone(struct zone *zone,
3405 unsigned long zone_start_pfn,
3407 enum memmap_context context)
3409 struct pglist_data *pgdat = zone->zone_pgdat;
3411 ret = zone_wait_table_init(zone, size);
3414 pgdat->nr_zones = zone_idx(zone) + 1;
3416 zone->zone_start_pfn = zone_start_pfn;
3418 mminit_dprintk(MMINIT_TRACE, "memmap_init",
3419 "Initialising map node %d zone %lu pfns %lu -> %lu\n",
3421 (unsigned long)zone_idx(zone),
3422 zone_start_pfn, (zone_start_pfn + size));
3424 zone_init_free_lists(zone);
3429 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
3431 * Basic iterator support. Return the first range of PFNs for a node
3432 * Note: nid == MAX_NUMNODES returns first region regardless of node
3434 static int __meminit first_active_region_index_in_nid(int nid)
3438 for (i = 0; i < nr_nodemap_entries; i++)
3439 if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
3446 * Basic iterator support. Return the next active range of PFNs for a node
3447 * Note: nid == MAX_NUMNODES returns next region regardless of node
3449 static int __meminit next_active_region_index_in_nid(int index, int nid)
3451 for (index = index + 1; index < nr_nodemap_entries; index++)
3452 if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
3458 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
3460 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
3461 * Architectures may implement their own version but if add_active_range()
3462 * was used and there are no special requirements, this is a convenient
3465 int __meminit __early_pfn_to_nid(unsigned long pfn)
3469 for (i = 0; i < nr_nodemap_entries; i++) {
3470 unsigned long start_pfn = early_node_map[i].start_pfn;
3471 unsigned long end_pfn = early_node_map[i].end_pfn;
3473 if (start_pfn <= pfn && pfn < end_pfn)
3474 return early_node_map[i].nid;
3476 /* This is a memory hole */
3479 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
3481 int __meminit early_pfn_to_nid(unsigned long pfn)
3485 nid = __early_pfn_to_nid(pfn);
3488 /* just returns 0 */
3492 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
3493 bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
3497 nid = __early_pfn_to_nid(pfn);
3498 if (nid >= 0 && nid != node)
3504 /* Basic iterator support to walk early_node_map[] */
3505 #define for_each_active_range_index_in_nid(i, nid) \
3506 for (i = first_active_region_index_in_nid(nid); i != -1; \
3507 i = next_active_region_index_in_nid(i, nid))
3510 * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
3511 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
3512 * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
3514 * If an architecture guarantees that all ranges registered with
3515 * add_active_ranges() contain no holes and may be freed, this
3516 * this function may be used instead of calling free_bootmem() manually.
3518 void __init free_bootmem_with_active_regions(int nid,
3519 unsigned long max_low_pfn)
3523 for_each_active_range_index_in_nid(i, nid) {
3524 unsigned long size_pages = 0;
3525 unsigned long end_pfn = early_node_map[i].end_pfn;
3527 if (early_node_map[i].start_pfn >= max_low_pfn)
3530 if (end_pfn > max_low_pfn)
3531 end_pfn = max_low_pfn;
3533 size_pages = end_pfn - early_node_map[i].start_pfn;
3534 free_bootmem_node(NODE_DATA(early_node_map[i].nid),
3535 PFN_PHYS(early_node_map[i].start_pfn),
3536 size_pages << PAGE_SHIFT);
3540 int __init add_from_early_node_map(struct range *range, int az,
3541 int nr_range, int nid)
3546 /* need to go over early_node_map to find out good range for node */
3547 for_each_active_range_index_in_nid(i, nid) {
3548 start = early_node_map[i].start_pfn;
3549 end = early_node_map[i].end_pfn;
3550 nr_range = add_range(range, az, nr_range, start, end);
3555 #ifdef CONFIG_NO_BOOTMEM
3556 void * __init __alloc_memory_core_early(int nid, u64 size, u64 align,
3557 u64 goal, u64 limit)
3562 /* need to go over early_node_map to find out good range for node */
3563 for_each_active_range_index_in_nid(i, nid) {
3565 u64 ei_start, ei_last;
3567 ei_last = early_node_map[i].end_pfn;
3568 ei_last <<= PAGE_SHIFT;
3569 ei_start = early_node_map[i].start_pfn;
3570 ei_start <<= PAGE_SHIFT;
3571 addr = find_early_area(ei_start, ei_last,
3572 goal, limit, size, align);
3578 printk(KERN_DEBUG "alloc (nid=%d %llx - %llx) (%llx - %llx) %llx %llx => %llx\n",
3580 ei_start, ei_last, goal, limit, size,
3584 ptr = phys_to_virt(addr);
3585 memset(ptr, 0, size);
3586 reserve_early_without_check(addr, addr + size, "BOOTMEM");
3595 void __init work_with_active_regions(int nid, work_fn_t work_fn, void *data)
3600 for_each_active_range_index_in_nid(i, nid) {
3601 ret = work_fn(early_node_map[i].start_pfn,
3602 early_node_map[i].end_pfn, data);
3608 * sparse_memory_present_with_active_regions - Call memory_present for each active range
3609 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
3611 * If an architecture guarantees that all ranges registered with
3612 * add_active_ranges() contain no holes and may be freed, this
3613 * function may be used instead of calling memory_present() manually.
3615 void __init sparse_memory_present_with_active_regions(int nid)
3619 for_each_active_range_index_in_nid(i, nid)
3620 memory_present(early_node_map[i].nid,
3621 early_node_map[i].start_pfn,
3622 early_node_map[i].end_pfn);
3626 * get_pfn_range_for_nid - Return the start and end page frames for a node
3627 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
3628 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
3629 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
3631 * It returns the start and end page frame of a node based on information
3632 * provided by an arch calling add_active_range(). If called for a node
3633 * with no available memory, a warning is printed and the start and end
3636 void __meminit get_pfn_range_for_nid(unsigned int nid,
3637 unsigned long *start_pfn, unsigned long *end_pfn)
3643 for_each_active_range_index_in_nid(i, nid) {
3644 *start_pfn = min(*start_pfn, early_node_map[i].start_pfn);
3645 *end_pfn = max(*end_pfn, early_node_map[i].end_pfn);
3648 if (*start_pfn == -1UL)
3653 * This finds a zone that can be used for ZONE_MOVABLE pages. The
3654 * assumption is made that zones within a node are ordered in monotonic
3655 * increasing memory addresses so that the "highest" populated zone is used
3657 static void __init find_usable_zone_for_movable(void)
3660 for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
3661 if (zone_index == ZONE_MOVABLE)
3664 if (arch_zone_highest_possible_pfn[zone_index] >
3665 arch_zone_lowest_possible_pfn[zone_index])
3669 VM_BUG_ON(zone_index == -1);
3670 movable_zone = zone_index;
3674 * The zone ranges provided by the architecture do not include ZONE_MOVABLE
3675 * because it is sized independant of architecture. Unlike the other zones,
3676 * the starting point for ZONE_MOVABLE is not fixed. It may be different
3677 * in each node depending on the size of each node and how evenly kernelcore
3678 * is distributed. This helper function adjusts the zone ranges
3679 * provided by the architecture for a given node by using the end of the
3680 * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
3681 * zones within a node are in order of monotonic increases memory addresses
3683 static void __meminit adjust_zone_range_for_zone_movable(int nid,
3684 unsigned long zone_type,
3685 unsigned long node_start_pfn,
3686 unsigned long node_end_pfn,
3687 unsigned long *zone_start_pfn,
3688 unsigned long *zone_end_pfn)
3690 /* Only adjust if ZONE_MOVABLE is on this node */
3691 if (zone_movable_pfn[nid]) {
3692 /* Size ZONE_MOVABLE */
3693 if (zone_type == ZONE_MOVABLE) {
3694 *zone_start_pfn = zone_movable_pfn[nid];
3695 *zone_end_pfn = min(node_end_pfn,
3696 arch_zone_highest_possible_pfn[movable_zone]);
3698 /* Adjust for ZONE_MOVABLE starting within this range */
3699 } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
3700 *zone_end_pfn > zone_movable_pfn[nid]) {
3701 *zone_end_pfn = zone_movable_pfn[nid];
3703 /* Check if this whole range is within ZONE_MOVABLE */
3704 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
3705 *zone_start_pfn = *zone_end_pfn;
3710 * Return the number of pages a zone spans in a node, including holes
3711 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
3713 static unsigned long __meminit zone_spanned_pages_in_node(int nid,
3714 unsigned long zone_type,
3715 unsigned long *ignored)
3717 unsigned long node_start_pfn, node_end_pfn;
3718 unsigned long zone_start_pfn, zone_end_pfn;
3720 /* Get the start and end of the node and zone */
3721 get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
3722 zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
3723 zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
3724 adjust_zone_range_for_zone_movable(nid, zone_type,
3725 node_start_pfn, node_end_pfn,
3726 &zone_start_pfn, &zone_end_pfn);
3728 /* Check that this node has pages within the zone's required range */
3729 if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
3732 /* Move the zone boundaries inside the node if necessary */
3733 zone_end_pfn = min(zone_end_pfn, node_end_pfn);
3734 zone_start_pfn = max(zone_start_pfn, node_start_pfn);
3736 /* Return the spanned pages */
3737 return zone_end_pfn - zone_start_pfn;
3741 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
3742 * then all holes in the requested range will be accounted for.
3744 unsigned long __meminit __absent_pages_in_range(int nid,
3745 unsigned long range_start_pfn,
3746 unsigned long range_end_pfn)
3749 unsigned long prev_end_pfn = 0, hole_pages = 0;
3750 unsigned long start_pfn;
3752 /* Find the end_pfn of the first active range of pfns in the node */
3753 i = first_active_region_index_in_nid(nid);
3757 prev_end_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
3759 /* Account for ranges before physical memory on this node */
3760 if (early_node_map[i].start_pfn > range_start_pfn)
3761 hole_pages = prev_end_pfn - range_start_pfn;
3763 /* Find all holes for the zone within the node */
3764 for (; i != -1; i = next_active_region_index_in_nid(i, nid)) {
3766 /* No need to continue if prev_end_pfn is outside the zone */
3767 if (prev_end_pfn >= range_end_pfn)
3770 /* Make sure the end of the zone is not within the hole */
3771 start_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
3772 prev_end_pfn = max(prev_end_pfn, range_start_pfn);
3774 /* Update the hole size cound and move on */
3775 if (start_pfn > range_start_pfn) {
3776 BUG_ON(prev_end_pfn > start_pfn);
3777 hole_pages += start_pfn - prev_end_pfn;
3779 prev_end_pfn = early_node_map[i].end_pfn;
3782 /* Account for ranges past physical memory on this node */
3783 if (range_end_pfn > prev_end_pfn)
3784 hole_pages += range_end_pfn -
3785 max(range_start_pfn, prev_end_pfn);
3791 * absent_pages_in_range - Return number of page frames in holes within a range
3792 * @start_pfn: The start PFN to start searching for holes
3793 * @end_pfn: The end PFN to stop searching for holes
3795 * It returns the number of pages frames in memory holes within a range.
3797 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
3798 unsigned long end_pfn)
3800 return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
3803 /* Return the number of page frames in holes in a zone on a node */
3804 static unsigned long __meminit zone_absent_pages_in_node(int nid,
3805 unsigned long zone_type,
3806 unsigned long *ignored)
3808 unsigned long node_start_pfn, node_end_pfn;
3809 unsigned long zone_start_pfn, zone_end_pfn;
3811 get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
3812 zone_start_pfn = max(arch_zone_lowest_possible_pfn[zone_type],
3814 zone_end_pfn = min(arch_zone_highest_possible_pfn[zone_type],
3817 adjust_zone_range_for_zone_movable(nid, zone_type,
3818 node_start_pfn, node_end_pfn,
3819 &zone_start_pfn, &zone_end_pfn);
3820 return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
3824 static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
3825 unsigned long zone_type,
3826 unsigned long *zones_size)
3828 return zones_size[zone_type];
3831 static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
3832 unsigned long zone_type,
3833 unsigned long *zholes_size)
3838 return zholes_size[zone_type];
3843 static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
3844 unsigned long *zones_size, unsigned long *zholes_size)
3846 unsigned long realtotalpages, totalpages = 0;
3849 for (i = 0; i < MAX_NR_ZONES; i++)
3850 totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
3852 pgdat->node_spanned_pages = totalpages;
3854 realtotalpages = totalpages;
3855 for (i = 0; i < MAX_NR_ZONES; i++)
3857 zone_absent_pages_in_node(pgdat->node_id, i,
3859 pgdat->node_present_pages = realtotalpages;
3860 printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
3864 #ifndef CONFIG_SPARSEMEM
3866 * Calculate the size of the zone->blockflags rounded to an unsigned long
3867 * Start by making sure zonesize is a multiple of pageblock_order by rounding
3868 * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
3869 * round what is now in bits to nearest long in bits, then return it in
3872 static unsigned long __init usemap_size(unsigned long zonesize)
3874 unsigned long usemapsize;
3876 usemapsize = roundup(zonesize, pageblock_nr_pages);
3877 usemapsize = usemapsize >> pageblock_order;
3878 usemapsize *= NR_PAGEBLOCK_BITS;
3879 usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
3881 return usemapsize / 8;
3884 static void __init setup_usemap(struct pglist_data *pgdat,
3885 struct zone *zone, unsigned long zonesize)
3887 unsigned long usemapsize = usemap_size(zonesize);
3888 zone->pageblock_flags = NULL;
3890 zone->pageblock_flags = alloc_bootmem_node(pgdat, usemapsize);
3893 static void inline setup_usemap(struct pglist_data *pgdat,
3894 struct zone *zone, unsigned long zonesize) {}
3895 #endif /* CONFIG_SPARSEMEM */
3897 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
3899 /* Return a sensible default order for the pageblock size. */
3900 static inline int pageblock_default_order(void)
3902 if (HPAGE_SHIFT > PAGE_SHIFT)
3903 return HUGETLB_PAGE_ORDER;
3908 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
3909 static inline void __init set_pageblock_order(unsigned int order)
3911 /* Check that pageblock_nr_pages has not already been setup */
3912 if (pageblock_order)
3916 * Assume the largest contiguous order of interest is a huge page.
3917 * This value may be variable depending on boot parameters on IA64
3919 pageblock_order = order;
3921 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
3924 * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
3925 * and pageblock_default_order() are unused as pageblock_order is set
3926 * at compile-time. See include/linux/pageblock-flags.h for the values of
3927 * pageblock_order based on the kernel config
3929 static inline int pageblock_default_order(unsigned int order)
3933 #define set_pageblock_order(x) do {} while (0)
3935 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
3938 * Set up the zone data structures:
3939 * - mark all pages reserved
3940 * - mark all memory queues empty
3941 * - clear the memory bitmaps
3943 static void __paginginit free_area_init_core(struct pglist_data *pgdat,
3944 unsigned long *zones_size, unsigned long *zholes_size)
3947 int nid = pgdat->node_id;
3948 unsigned long zone_start_pfn = pgdat->node_start_pfn;
3951 pgdat_resize_init(pgdat);
3952 pgdat->nr_zones = 0;
3953 init_waitqueue_head(&pgdat->kswapd_wait);
3954 pgdat->kswapd_max_order = 0;
3955 pgdat_page_cgroup_init(pgdat);
3957 for (j = 0; j < MAX_NR_ZONES; j++) {
3958 struct zone *zone = pgdat->node_zones + j;
3959 unsigned long size, realsize, memmap_pages;
3962 size = zone_spanned_pages_in_node(nid, j, zones_size);
3963 realsize = size - zone_absent_pages_in_node(nid, j,
3967 * Adjust realsize so that it accounts for how much memory
3968 * is used by this zone for memmap. This affects the watermark
3969 * and per-cpu initialisations
3972 PAGE_ALIGN(size * sizeof(struct page)) >> PAGE_SHIFT;
3973 if (realsize >= memmap_pages) {
3974 realsize -= memmap_pages;
3977 " %s zone: %lu pages used for memmap\n",
3978 zone_names[j], memmap_pages);
3981 " %s zone: %lu pages exceeds realsize %lu\n",
3982 zone_names[j], memmap_pages, realsize);
3984 /* Account for reserved pages */
3985 if (j == 0 && realsize > dma_reserve) {
3986 realsize -= dma_reserve;
3987 printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
3988 zone_names[0], dma_reserve);
3991 if (!is_highmem_idx(j))
3992 nr_kernel_pages += realsize;
3993 nr_all_pages += realsize;
3995 zone->spanned_pages = size;
3996 zone->present_pages = realsize;
3999 zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
4001 zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
4003 zone->name = zone_names[j];
4004 spin_lock_init(&zone->lock);
4005 spin_lock_init(&zone->lru_lock);
4006 zone_seqlock_init(zone);
4007 zone->zone_pgdat = pgdat;
4009 zone->prev_priority = DEF_PRIORITY;
4011 zone_pcp_init(zone);
4013 INIT_LIST_HEAD(&zone->lru[l].list);
4014 zone->reclaim_stat.nr_saved_scan[l] = 0;
4016 zone->reclaim_stat.recent_rotated[0] = 0;
4017 zone->reclaim_stat.recent_rotated[1] = 0;
4018 zone->reclaim_stat.recent_scanned[0] = 0;
4019 zone->reclaim_stat.recent_scanned[1] = 0;
4020 zap_zone_vm_stats(zone);
4025 set_pageblock_order(pageblock_default_order());
4026 setup_usemap(pgdat, zone, size);
4027 ret = init_currently_empty_zone(zone, zone_start_pfn,
4028 size, MEMMAP_EARLY);
4030 memmap_init(size, nid, j, zone_start_pfn);
4031 zone_start_pfn += size;
4035 static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
4037 /* Skip empty nodes */
4038 if (!pgdat->node_spanned_pages)
4041 #ifdef CONFIG_FLAT_NODE_MEM_MAP
4042 /* ia64 gets its own node_mem_map, before this, without bootmem */
4043 if (!pgdat->node_mem_map) {
4044 unsigned long size, start, end;
4048 * The zone's endpoints aren't required to be MAX_ORDER
4049 * aligned but the node_mem_map endpoints must be in order
4050 * for the buddy allocator to function correctly.
4052 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
4053 end = pgdat->node_start_pfn + pgdat->node_spanned_pages;
4054 end = ALIGN(end, MAX_ORDER_NR_PAGES);
4055 size = (end - start) * sizeof(struct page);
4056 map = alloc_remap(pgdat->node_id, size);
4058 map = alloc_bootmem_node(pgdat, size);
4059 pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
4061 #ifndef CONFIG_NEED_MULTIPLE_NODES
4063 * With no DISCONTIG, the global mem_map is just set as node 0's
4065 if (pgdat == NODE_DATA(0)) {
4066 mem_map = NODE_DATA(0)->node_mem_map;
4067 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
4068 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
4069 mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
4070 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
4073 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
4076 void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
4077 unsigned long node_start_pfn, unsigned long *zholes_size)
4079 pg_data_t *pgdat = NODE_DATA(nid);
4081 pgdat->node_id = nid;
4082 pgdat->node_start_pfn = node_start_pfn;
4083 calculate_node_totalpages(pgdat, zones_size, zholes_size);
4085 alloc_node_mem_map(pgdat);
4086 #ifdef CONFIG_FLAT_NODE_MEM_MAP
4087 printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
4088 nid, (unsigned long)pgdat,
4089 (unsigned long)pgdat->node_mem_map);
4092 free_area_init_core(pgdat, zones_size, zholes_size);
4095 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
4097 #if MAX_NUMNODES > 1
4099 * Figure out the number of possible node ids.
4101 static void __init setup_nr_node_ids(void)
4104 unsigned int highest = 0;
4106 for_each_node_mask(node, node_possible_map)
4108 nr_node_ids = highest + 1;
4111 static inline void setup_nr_node_ids(void)
4117 * add_active_range - Register a range of PFNs backed by physical memory
4118 * @nid: The node ID the range resides on
4119 * @start_pfn: The start PFN of the available physical memory
4120 * @end_pfn: The end PFN of the available physical memory
4122 * These ranges are stored in an early_node_map[] and later used by
4123 * free_area_init_nodes() to calculate zone sizes and holes. If the
4124 * range spans a memory hole, it is up to the architecture to ensure
4125 * the memory is not freed by the bootmem allocator. If possible
4126 * the range being registered will be merged with existing ranges.
4128 void __init add_active_range(unsigned int nid, unsigned long start_pfn,
4129 unsigned long end_pfn)
4133 mminit_dprintk(MMINIT_TRACE, "memory_register",
4134 "Entering add_active_range(%d, %#lx, %#lx) "
4135 "%d entries of %d used\n",
4136 nid, start_pfn, end_pfn,
4137 nr_nodemap_entries, MAX_ACTIVE_REGIONS);
4139 mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
4141 /* Merge with existing active regions if possible */
4142 for (i = 0; i < nr_nodemap_entries; i++) {
4143 if (early_node_map[i].nid != nid)
4146 /* Skip if an existing region covers this new one */
4147 if (start_pfn >= early_node_map[i].start_pfn &&
4148 end_pfn <= early_node_map[i].end_pfn)
4151 /* Merge forward if suitable */
4152 if (start_pfn <= early_node_map[i].end_pfn &&
4153 end_pfn > early_node_map[i].end_pfn) {
4154 early_node_map[i].end_pfn = end_pfn;
4158 /* Merge backward if suitable */
4159 if (start_pfn < early_node_map[i].start_pfn &&
4160 end_pfn >= early_node_map[i].start_pfn) {
4161 early_node_map[i].start_pfn = start_pfn;
4166 /* Check that early_node_map is large enough */
4167 if (i >= MAX_ACTIVE_REGIONS) {
4168 printk(KERN_CRIT "More than %d memory regions, truncating\n",
4169 MAX_ACTIVE_REGIONS);
4173 early_node_map[i].nid = nid;
4174 early_node_map[i].start_pfn = start_pfn;
4175 early_node_map[i].end_pfn = end_pfn;
4176 nr_nodemap_entries = i + 1;
4180 * remove_active_range - Shrink an existing registered range of PFNs
4181 * @nid: The node id the range is on that should be shrunk
4182 * @start_pfn: The new PFN of the range
4183 * @end_pfn: The new PFN of the range
4185 * i386 with NUMA use alloc_remap() to store a node_mem_map on a local node.
4186 * The map is kept near the end physical page range that has already been
4187 * registered. This function allows an arch to shrink an existing registered
4190 void __init remove_active_range(unsigned int nid, unsigned long start_pfn,
4191 unsigned long end_pfn)
4196 printk(KERN_DEBUG "remove_active_range (%d, %lu, %lu)\n",
4197 nid, start_pfn, end_pfn);
4199 /* Find the old active region end and shrink */
4200 for_each_active_range_index_in_nid(i, nid) {
4201 if (early_node_map[i].start_pfn >= start_pfn &&
4202 early_node_map[i].end_pfn <= end_pfn) {
4204 early_node_map[i].start_pfn = 0;
4205 early_node_map[i].end_pfn = 0;
4209 if (early_node_map[i].start_pfn < start_pfn &&
4210 early_node_map[i].end_pfn > start_pfn) {
4211 unsigned long temp_end_pfn = early_node_map[i].end_pfn;
4212 early_node_map[i].end_pfn = start_pfn;
4213 if (temp_end_pfn > end_pfn)
4214 add_active_range(nid, end_pfn, temp_end_pfn);
4217 if (early_node_map[i].start_pfn >= start_pfn &&
4218 early_node_map[i].end_pfn > end_pfn &&
4219 early_node_map[i].start_pfn < end_pfn) {
4220 early_node_map[i].start_pfn = end_pfn;
4228 /* remove the blank ones */
4229 for (i = nr_nodemap_entries - 1; i > 0; i--) {
4230 if (early_node_map[i].nid != nid)
4232 if (early_node_map[i].end_pfn)
4234 /* we found it, get rid of it */
4235 for (j = i; j < nr_nodemap_entries - 1; j++)
4236 memcpy(&early_node_map[j], &early_node_map[j+1],
4237 sizeof(early_node_map[j]));
4238 j = nr_nodemap_entries - 1;
4239 memset(&early_node_map[j], 0, sizeof(early_node_map[j]));
4240 nr_nodemap_entries--;
4245 * remove_all_active_ranges - Remove all currently registered regions
4247 * During discovery, it may be found that a table like SRAT is invalid
4248 * and an alternative discovery method must be used. This function removes
4249 * all currently registered regions.
4251 void __init remove_all_active_ranges(void)
4253 memset(early_node_map, 0, sizeof(early_node_map));
4254 nr_nodemap_entries = 0;
4257 /* Compare two active node_active_regions */
4258 static int __init cmp_node_active_region(const void *a, const void *b)
4260 struct node_active_region *arange = (struct node_active_region *)a;
4261 struct node_active_region *brange = (struct node_active_region *)b;
4263 /* Done this way to avoid overflows */
4264 if (arange->start_pfn > brange->start_pfn)
4266 if (arange->start_pfn < brange->start_pfn)
4272 /* sort the node_map by start_pfn */
4273 void __init sort_node_map(void)
4275 sort(early_node_map, (size_t)nr_nodemap_entries,
4276 sizeof(struct node_active_region),
4277 cmp_node_active_region, NULL);
4280 /* Find the lowest pfn for a node */
4281 static unsigned long __init find_min_pfn_for_node(int nid)
4284 unsigned long min_pfn = ULONG_MAX;
4286 /* Assuming a sorted map, the first range found has the starting pfn */
4287 for_each_active_range_index_in_nid(i, nid)
4288 min_pfn = min(min_pfn, early_node_map[i].start_pfn);
4290 if (min_pfn == ULONG_MAX) {
4292 "Could not find start_pfn for node %d\n", nid);
4300 * find_min_pfn_with_active_regions - Find the minimum PFN registered
4302 * It returns the minimum PFN based on information provided via
4303 * add_active_range().
4305 unsigned long __init find_min_pfn_with_active_regions(void)
4307 return find_min_pfn_for_node(MAX_NUMNODES);
4311 * early_calculate_totalpages()
4312 * Sum pages in active regions for movable zone.
4313 * Populate N_HIGH_MEMORY for calculating usable_nodes.
4315 static unsigned long __init early_calculate_totalpages(void)
4318 unsigned long totalpages = 0;
4320 for (i = 0; i < nr_nodemap_entries; i++) {
4321 unsigned long pages = early_node_map[i].end_pfn -
4322 early_node_map[i].start_pfn;
4323 totalpages += pages;
4325 node_set_state(early_node_map[i].nid, N_HIGH_MEMORY);
4331 * Find the PFN the Movable zone begins in each node. Kernel memory
4332 * is spread evenly between nodes as long as the nodes have enough
4333 * memory. When they don't, some nodes will have more kernelcore than
4336 static void __init find_zone_movable_pfns_for_nodes(unsigned long *movable_pfn)
4339 unsigned long usable_startpfn;
4340 unsigned long kernelcore_node, kernelcore_remaining;
4341 /* save the state before borrow the nodemask */
4342 nodemask_t saved_node_state = node_states[N_HIGH_MEMORY];
4343 unsigned long totalpages = early_calculate_totalpages();
4344 int usable_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
4347 * If movablecore was specified, calculate what size of
4348 * kernelcore that corresponds so that memory usable for
4349 * any allocation type is evenly spread. If both kernelcore
4350 * and movablecore are specified, then the value of kernelcore
4351 * will be used for required_kernelcore if it's greater than
4352 * what movablecore would have allowed.
4354 if (required_movablecore) {
4355 unsigned long corepages;
4358 * Round-up so that ZONE_MOVABLE is at least as large as what
4359 * was requested by the user
4361 required_movablecore =
4362 roundup(required_movablecore, MAX_ORDER_NR_PAGES);
4363 corepages = totalpages - required_movablecore;
4365 required_kernelcore = max(required_kernelcore, corepages);
4368 /* If kernelcore was not specified, there is no ZONE_MOVABLE */
4369 if (!required_kernelcore)
4372 /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
4373 find_usable_zone_for_movable();
4374 usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
4377 /* Spread kernelcore memory as evenly as possible throughout nodes */
4378 kernelcore_node = required_kernelcore / usable_nodes;
4379 for_each_node_state(nid, N_HIGH_MEMORY) {
4381 * Recalculate kernelcore_node if the division per node
4382 * now exceeds what is necessary to satisfy the requested
4383 * amount of memory for the kernel
4385 if (required_kernelcore < kernelcore_node)
4386 kernelcore_node = required_kernelcore / usable_nodes;
4389 * As the map is walked, we track how much memory is usable
4390 * by the kernel using kernelcore_remaining. When it is
4391 * 0, the rest of the node is usable by ZONE_MOVABLE
4393 kernelcore_remaining = kernelcore_node;
4395 /* Go through each range of PFNs within this node */
4396 for_each_active_range_index_in_nid(i, nid) {
4397 unsigned long start_pfn, end_pfn;
4398 unsigned long size_pages;
4400 start_pfn = max(early_node_map[i].start_pfn,
4401 zone_movable_pfn[nid]);
4402 end_pfn = early_node_map[i].end_pfn;
4403 if (start_pfn >= end_pfn)
4406 /* Account for what is only usable for kernelcore */
4407 if (start_pfn < usable_startpfn) {
4408 unsigned long kernel_pages;
4409 kernel_pages = min(end_pfn, usable_startpfn)
4412 kernelcore_remaining -= min(kernel_pages,
4413 kernelcore_remaining);
4414 required_kernelcore -= min(kernel_pages,
4415 required_kernelcore);
4417 /* Continue if range is now fully accounted */
4418 if (end_pfn <= usable_startpfn) {
4421 * Push zone_movable_pfn to the end so
4422 * that if we have to rebalance
4423 * kernelcore across nodes, we will
4424 * not double account here
4426 zone_movable_pfn[nid] = end_pfn;
4429 start_pfn = usable_startpfn;
4433 * The usable PFN range for ZONE_MOVABLE is from
4434 * start_pfn->end_pfn. Calculate size_pages as the
4435 * number of pages used as kernelcore
4437 size_pages = end_pfn - start_pfn;
4438 if (size_pages > kernelcore_remaining)
4439 size_pages = kernelcore_remaining;
4440 zone_movable_pfn[nid] = start_pfn + size_pages;
4443 * Some kernelcore has been met, update counts and
4444 * break if the kernelcore for this node has been
4447 required_kernelcore -= min(required_kernelcore,
4449 kernelcore_remaining -= size_pages;
4450 if (!kernelcore_remaining)
4456 * If there is still required_kernelcore, we do another pass with one
4457 * less node in the count. This will push zone_movable_pfn[nid] further
4458 * along on the nodes that still have memory until kernelcore is
4462 if (usable_nodes && required_kernelcore > usable_nodes)
4465 /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
4466 for (nid = 0; nid < MAX_NUMNODES; nid++)
4467 zone_movable_pfn[nid] =
4468 roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
4471 /* restore the node_state */
4472 node_states[N_HIGH_MEMORY] = saved_node_state;
4475 /* Any regular memory on that node ? */
4476 static void check_for_regular_memory(pg_data_t *pgdat)
4478 #ifdef CONFIG_HIGHMEM
4479 enum zone_type zone_type;
4481 for (zone_type = 0; zone_type <= ZONE_NORMAL; zone_type++) {
4482 struct zone *zone = &pgdat->node_zones[zone_type];
4483 if (zone->present_pages)
4484 node_set_state(zone_to_nid(zone), N_NORMAL_MEMORY);
4490 * free_area_init_nodes - Initialise all pg_data_t and zone data
4491 * @max_zone_pfn: an array of max PFNs for each zone
4493 * This will call free_area_init_node() for each active node in the system.
4494 * Using the page ranges provided by add_active_range(), the size of each
4495 * zone in each node and their holes is calculated. If the maximum PFN
4496 * between two adjacent zones match, it is assumed that the zone is empty.
4497 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
4498 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
4499 * starts where the previous one ended. For example, ZONE_DMA32 starts
4500 * at arch_max_dma_pfn.
4502 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
4507 /* Sort early_node_map as initialisation assumes it is sorted */
4510 /* Record where the zone boundaries are */
4511 memset(arch_zone_lowest_possible_pfn, 0,
4512 sizeof(arch_zone_lowest_possible_pfn));
4513 memset(arch_zone_highest_possible_pfn, 0,
4514 sizeof(arch_zone_highest_possible_pfn));
4515 arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
4516 arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
4517 for (i = 1; i < MAX_NR_ZONES; i++) {
4518 if (i == ZONE_MOVABLE)
4520 arch_zone_lowest_possible_pfn[i] =
4521 arch_zone_highest_possible_pfn[i-1];
4522 arch_zone_highest_possible_pfn[i] =
4523 max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
4525 arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
4526 arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
4528 /* Find the PFNs that ZONE_MOVABLE begins at in each node */
4529 memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
4530 find_zone_movable_pfns_for_nodes(zone_movable_pfn);
4532 /* Print out the zone ranges */
4533 printk("Zone PFN ranges:\n");
4534 for (i = 0; i < MAX_NR_ZONES; i++) {
4535 if (i == ZONE_MOVABLE)
4537 printk(" %-8s ", zone_names[i]);
4538 if (arch_zone_lowest_possible_pfn[i] ==
4539 arch_zone_highest_possible_pfn[i])
4542 printk("%0#10lx -> %0#10lx\n",
4543 arch_zone_lowest_possible_pfn[i],
4544 arch_zone_highest_possible_pfn[i]);
4547 /* Print out the PFNs ZONE_MOVABLE begins at in each node */
4548 printk("Movable zone start PFN for each node\n");
4549 for (i = 0; i < MAX_NUMNODES; i++) {
4550 if (zone_movable_pfn[i])
4551 printk(" Node %d: %lu\n", i, zone_movable_pfn[i]);
4554 /* Print out the early_node_map[] */
4555 printk("early_node_map[%d] active PFN ranges\n", nr_nodemap_entries);
4556 for (i = 0; i < nr_nodemap_entries; i++)
4557 printk(" %3d: %0#10lx -> %0#10lx\n", early_node_map[i].nid,
4558 early_node_map[i].start_pfn,
4559 early_node_map[i].end_pfn);
4561 /* Initialise every node */
4562 mminit_verify_pageflags_layout();
4563 setup_nr_node_ids();
4564 for_each_online_node(nid) {
4565 pg_data_t *pgdat = NODE_DATA(nid);
4566 free_area_init_node(nid, NULL,
4567 find_min_pfn_for_node(nid), NULL);
4569 /* Any memory on that node */
4570 if (pgdat->node_present_pages)
4571 node_set_state(nid, N_HIGH_MEMORY);
4572 check_for_regular_memory(pgdat);
4576 static int __init cmdline_parse_core(char *p, unsigned long *core)
4578 unsigned long long coremem;
4582 coremem = memparse(p, &p);
4583 *core = coremem >> PAGE_SHIFT;
4585 /* Paranoid check that UL is enough for the coremem value */
4586 WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
4592 * kernelcore=size sets the amount of memory for use for allocations that
4593 * cannot be reclaimed or migrated.
4595 static int __init cmdline_parse_kernelcore(char *p)
4597 return cmdline_parse_core(p, &required_kernelcore);
4601 * movablecore=size sets the amount of memory for use for allocations that
4602 * can be reclaimed or migrated.
4604 static int __init cmdline_parse_movablecore(char *p)
4606 return cmdline_parse_core(p, &required_movablecore);
4609 early_param("kernelcore", cmdline_parse_kernelcore);
4610 early_param("movablecore", cmdline_parse_movablecore);
4612 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
4615 * set_dma_reserve - set the specified number of pages reserved in the first zone
4616 * @new_dma_reserve: The number of pages to mark reserved
4618 * The per-cpu batchsize and zone watermarks are determined by present_pages.
4619 * In the DMA zone, a significant percentage may be consumed by kernel image
4620 * and other unfreeable allocations which can skew the watermarks badly. This
4621 * function may optionally be used to account for unfreeable pages in the
4622 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
4623 * smaller per-cpu batchsize.
4625 void __init set_dma_reserve(unsigned long new_dma_reserve)
4627 dma_reserve = new_dma_reserve;
4630 #ifndef CONFIG_NEED_MULTIPLE_NODES
4631 struct pglist_data __refdata contig_page_data = {
4632 #ifndef CONFIG_NO_BOOTMEM
4633 .bdata = &bootmem_node_data[0]
4636 EXPORT_SYMBOL(contig_page_data);
4639 void __init free_area_init(unsigned long *zones_size)
4641 free_area_init_node(0, zones_size,
4642 __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
4645 static int page_alloc_cpu_notify(struct notifier_block *self,
4646 unsigned long action, void *hcpu)
4648 int cpu = (unsigned long)hcpu;
4650 if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
4654 * Spill the event counters of the dead processor
4655 * into the current processors event counters.
4656 * This artificially elevates the count of the current
4659 vm_events_fold_cpu(cpu);
4662 * Zero the differential counters of the dead processor
4663 * so that the vm statistics are consistent.
4665 * This is only okay since the processor is dead and cannot
4666 * race with what we are doing.
4668 refresh_cpu_vm_stats(cpu);
4673 void __init page_alloc_init(void)
4675 hotcpu_notifier(page_alloc_cpu_notify, 0);
4679 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
4680 * or min_free_kbytes changes.
4682 static void calculate_totalreserve_pages(void)
4684 struct pglist_data *pgdat;
4685 unsigned long reserve_pages = 0;
4686 enum zone_type i, j;
4688 for_each_online_pgdat(pgdat) {
4689 for (i = 0; i < MAX_NR_ZONES; i++) {
4690 struct zone *zone = pgdat->node_zones + i;
4691 unsigned long max = 0;
4693 /* Find valid and maximum lowmem_reserve in the zone */
4694 for (j = i; j < MAX_NR_ZONES; j++) {
4695 if (zone->lowmem_reserve[j] > max)
4696 max = zone->lowmem_reserve[j];
4699 /* we treat the high watermark as reserved pages. */
4700 max += high_wmark_pages(zone);
4702 if (max > zone->present_pages)
4703 max = zone->present_pages;
4704 reserve_pages += max;
4707 totalreserve_pages = reserve_pages;
4711 * setup_per_zone_lowmem_reserve - called whenever
4712 * sysctl_lower_zone_reserve_ratio changes. Ensures that each zone
4713 * has a correct pages reserved value, so an adequate number of
4714 * pages are left in the zone after a successful __alloc_pages().
4716 static void setup_per_zone_lowmem_reserve(void)
4718 struct pglist_data *pgdat;
4719 enum zone_type j, idx;
4721 for_each_online_pgdat(pgdat) {
4722 for (j = 0; j < MAX_NR_ZONES; j++) {
4723 struct zone *zone = pgdat->node_zones + j;
4724 unsigned long present_pages = zone->present_pages;
4726 zone->lowmem_reserve[j] = 0;
4730 struct zone *lower_zone;
4734 if (sysctl_lowmem_reserve_ratio[idx] < 1)
4735 sysctl_lowmem_reserve_ratio[idx] = 1;
4737 lower_zone = pgdat->node_zones + idx;
4738 lower_zone->lowmem_reserve[j] = present_pages /
4739 sysctl_lowmem_reserve_ratio[idx];
4740 present_pages += lower_zone->present_pages;
4745 /* update totalreserve_pages */
4746 calculate_totalreserve_pages();
4750 * setup_per_zone_wmarks - called when min_free_kbytes changes
4751 * or when memory is hot-{added|removed}
4753 * Ensures that the watermark[min,low,high] values for each zone are set
4754 * correctly with respect to min_free_kbytes.
4756 void setup_per_zone_wmarks(void)
4758 unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
4759 unsigned long lowmem_pages = 0;
4761 unsigned long flags;
4763 /* Calculate total number of !ZONE_HIGHMEM pages */
4764 for_each_zone(zone) {
4765 if (!is_highmem(zone))
4766 lowmem_pages += zone->present_pages;
4769 for_each_zone(zone) {
4772 spin_lock_irqsave(&zone->lock, flags);
4773 tmp = (u64)pages_min * zone->present_pages;
4774 do_div(tmp, lowmem_pages);
4775 if (is_highmem(zone)) {
4777 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
4778 * need highmem pages, so cap pages_min to a small
4781 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
4782 * deltas controls asynch page reclaim, and so should
4783 * not be capped for highmem.
4787 min_pages = zone->present_pages / 1024;
4788 if (min_pages < SWAP_CLUSTER_MAX)
4789 min_pages = SWAP_CLUSTER_MAX;
4790 if (min_pages > 128)
4792 zone->watermark[WMARK_MIN] = min_pages;
4795 * If it's a lowmem zone, reserve a number of pages
4796 * proportionate to the zone's size.
4798 zone->watermark[WMARK_MIN] = tmp;
4801 zone->watermark[WMARK_LOW] = min_wmark_pages(zone) + (tmp >> 2);
4802 zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
4803 setup_zone_migrate_reserve(zone);
4804 spin_unlock_irqrestore(&zone->lock, flags);
4807 /* update totalreserve_pages */
4808 calculate_totalreserve_pages();
4812 * The inactive anon list should be small enough that the VM never has to
4813 * do too much work, but large enough that each inactive page has a chance
4814 * to be referenced again before it is swapped out.
4816 * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
4817 * INACTIVE_ANON pages on this zone's LRU, maintained by the
4818 * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
4819 * the anonymous pages are kept on the inactive list.
4822 * memory ratio inactive anon
4823 * -------------------------------------
4832 void calculate_zone_inactive_ratio(struct zone *zone)
4834 unsigned int gb, ratio;
4836 /* Zone size in gigabytes */
4837 gb = zone->present_pages >> (30 - PAGE_SHIFT);
4839 ratio = int_sqrt(10 * gb);
4843 zone->inactive_ratio = ratio;
4846 static void __init setup_per_zone_inactive_ratio(void)
4851 calculate_zone_inactive_ratio(zone);
4855 * Initialise min_free_kbytes.
4857 * For small machines we want it small (128k min). For large machines
4858 * we want it large (64MB max). But it is not linear, because network
4859 * bandwidth does not increase linearly with machine size. We use
4861 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
4862 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
4878 static int __init init_per_zone_wmark_min(void)
4880 unsigned long lowmem_kbytes;
4882 lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
4884 min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
4885 if (min_free_kbytes < 128)
4886 min_free_kbytes = 128;
4887 if (min_free_kbytes > 65536)
4888 min_free_kbytes = 65536;
4889 setup_per_zone_wmarks();
4890 setup_per_zone_lowmem_reserve();
4891 setup_per_zone_inactive_ratio();
4894 module_init(init_per_zone_wmark_min)
4897 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
4898 * that we can call two helper functions whenever min_free_kbytes
4901 int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
4902 void __user *buffer, size_t *length, loff_t *ppos)
4904 proc_dointvec(table, write, buffer, length, ppos);
4906 setup_per_zone_wmarks();
4911 int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
4912 void __user *buffer, size_t *length, loff_t *ppos)
4917 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
4922 zone->min_unmapped_pages = (zone->present_pages *
4923 sysctl_min_unmapped_ratio) / 100;
4927 int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
4928 void __user *buffer, size_t *length, loff_t *ppos)
4933 rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
4938 zone->min_slab_pages = (zone->present_pages *
4939 sysctl_min_slab_ratio) / 100;
4945 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
4946 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
4947 * whenever sysctl_lowmem_reserve_ratio changes.
4949 * The reserve ratio obviously has absolutely no relation with the
4950 * minimum watermarks. The lowmem reserve ratio can only make sense
4951 * if in function of the boot time zone sizes.
4953 int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
4954 void __user *buffer, size_t *length, loff_t *ppos)
4956 proc_dointvec_minmax(table, write, buffer, length, ppos);
4957 setup_per_zone_lowmem_reserve();
4962 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
4963 * cpu. It is the fraction of total pages in each zone that a hot per cpu pagelist
4964 * can have before it gets flushed back to buddy allocator.
4967 int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
4968 void __user *buffer, size_t *length, loff_t *ppos)
4974 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
4975 if (!write || (ret == -EINVAL))
4977 for_each_populated_zone(zone) {
4978 for_each_possible_cpu(cpu) {
4980 high = zone->present_pages / percpu_pagelist_fraction;
4981 setup_pagelist_highmark(
4982 per_cpu_ptr(zone->pageset, cpu), high);
4988 int hashdist = HASHDIST_DEFAULT;
4991 static int __init set_hashdist(char *str)
4995 hashdist = simple_strtoul(str, &str, 0);
4998 __setup("hashdist=", set_hashdist);
5002 * allocate a large system hash table from bootmem
5003 * - it is assumed that the hash table must contain an exact power-of-2
5004 * quantity of entries
5005 * - limit is the number of hash buckets, not the total allocation size
5007 void *__init alloc_large_system_hash(const char *tablename,
5008 unsigned long bucketsize,
5009 unsigned long numentries,
5012 unsigned int *_hash_shift,
5013 unsigned int *_hash_mask,
5014 unsigned long limit)
5016 unsigned long long max = limit;
5017 unsigned long log2qty, size;
5020 /* allow the kernel cmdline to have a say */
5022 /* round applicable memory size up to nearest megabyte */
5023 numentries = nr_kernel_pages;
5024 numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
5025 numentries >>= 20 - PAGE_SHIFT;
5026 numentries <<= 20 - PAGE_SHIFT;
5028 /* limit to 1 bucket per 2^scale bytes of low memory */
5029 if (scale > PAGE_SHIFT)
5030 numentries >>= (scale - PAGE_SHIFT);
5032 numentries <<= (PAGE_SHIFT - scale);
5034 /* Make sure we've got at least a 0-order allocation.. */
5035 if (unlikely(flags & HASH_SMALL)) {
5036 /* Makes no sense without HASH_EARLY */
5037 WARN_ON(!(flags & HASH_EARLY));
5038 if (!(numentries >> *_hash_shift)) {
5039 numentries = 1UL << *_hash_shift;
5040 BUG_ON(!numentries);
5042 } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
5043 numentries = PAGE_SIZE / bucketsize;
5045 numentries = roundup_pow_of_two(numentries);
5047 /* limit allocation size to 1/16 total memory by default */
5049 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
5050 do_div(max, bucketsize);
5053 if (numentries > max)
5056 log2qty = ilog2(numentries);
5059 size = bucketsize << log2qty;
5060 if (flags & HASH_EARLY)
5061 table = alloc_bootmem_nopanic(size);
5063 table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
5066 * If bucketsize is not a power-of-two, we may free
5067 * some pages at the end of hash table which
5068 * alloc_pages_exact() automatically does
5070 if (get_order(size) < MAX_ORDER) {
5071 table = alloc_pages_exact(size, GFP_ATOMIC);
5072 kmemleak_alloc(table, size, 1, GFP_ATOMIC);
5075 } while (!table && size > PAGE_SIZE && --log2qty);
5078 panic("Failed to allocate %s hash table\n", tablename);
5080 printk(KERN_INFO "%s hash table entries: %d (order: %d, %lu bytes)\n",
5083 ilog2(size) - PAGE_SHIFT,
5087 *_hash_shift = log2qty;
5089 *_hash_mask = (1 << log2qty) - 1;
5094 /* Return a pointer to the bitmap storing bits affecting a block of pages */
5095 static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
5098 #ifdef CONFIG_SPARSEMEM
5099 return __pfn_to_section(pfn)->pageblock_flags;
5101 return zone->pageblock_flags;
5102 #endif /* CONFIG_SPARSEMEM */
5105 static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
5107 #ifdef CONFIG_SPARSEMEM
5108 pfn &= (PAGES_PER_SECTION-1);
5109 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5111 pfn = pfn - zone->zone_start_pfn;
5112 return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5113 #endif /* CONFIG_SPARSEMEM */
5117 * get_pageblock_flags_group - Return the requested group of flags for the pageblock_nr_pages block of pages
5118 * @page: The page within the block of interest
5119 * @start_bitidx: The first bit of interest to retrieve
5120 * @end_bitidx: The last bit of interest
5121 * returns pageblock_bits flags
5123 unsigned long get_pageblock_flags_group(struct page *page,
5124 int start_bitidx, int end_bitidx)
5127 unsigned long *bitmap;
5128 unsigned long pfn, bitidx;
5129 unsigned long flags = 0;
5130 unsigned long value = 1;
5132 zone = page_zone(page);
5133 pfn = page_to_pfn(page);
5134 bitmap = get_pageblock_bitmap(zone, pfn);
5135 bitidx = pfn_to_bitidx(zone, pfn);
5137 for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5138 if (test_bit(bitidx + start_bitidx, bitmap))
5145 * set_pageblock_flags_group - Set the requested group of flags for a pageblock_nr_pages block of pages
5146 * @page: The page within the block of interest
5147 * @start_bitidx: The first bit of interest
5148 * @end_bitidx: The last bit of interest
5149 * @flags: The flags to set
5151 void set_pageblock_flags_group(struct page *page, unsigned long flags,
5152 int start_bitidx, int end_bitidx)
5155 unsigned long *bitmap;
5156 unsigned long pfn, bitidx;
5157 unsigned long value = 1;
5159 zone = page_zone(page);
5160 pfn = page_to_pfn(page);
5161 bitmap = get_pageblock_bitmap(zone, pfn);
5162 bitidx = pfn_to_bitidx(zone, pfn);
5163 VM_BUG_ON(pfn < zone->zone_start_pfn);
5164 VM_BUG_ON(pfn >= zone->zone_start_pfn + zone->spanned_pages);
5166 for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5168 __set_bit(bitidx + start_bitidx, bitmap);
5170 __clear_bit(bitidx + start_bitidx, bitmap);
5174 * This is designed as sub function...plz see page_isolation.c also.
5175 * set/clear page block's type to be ISOLATE.
5176 * page allocater never alloc memory from ISOLATE block.
5179 int set_migratetype_isolate(struct page *page)
5182 struct page *curr_page;
5183 unsigned long flags, pfn, iter;
5184 unsigned long immobile = 0;
5185 struct memory_isolate_notify arg;
5190 zone = page_zone(page);
5191 zone_idx = zone_idx(zone);
5193 spin_lock_irqsave(&zone->lock, flags);
5194 if (get_pageblock_migratetype(page) == MIGRATE_MOVABLE ||
5195 zone_idx == ZONE_MOVABLE) {
5200 pfn = page_to_pfn(page);
5201 arg.start_pfn = pfn;
5202 arg.nr_pages = pageblock_nr_pages;
5203 arg.pages_found = 0;
5206 * It may be possible to isolate a pageblock even if the
5207 * migratetype is not MIGRATE_MOVABLE. The memory isolation
5208 * notifier chain is used by balloon drivers to return the
5209 * number of pages in a range that are held by the balloon
5210 * driver to shrink memory. If all the pages are accounted for
5211 * by balloons, are free, or on the LRU, isolation can continue.
5212 * Later, for example, when memory hotplug notifier runs, these
5213 * pages reported as "can be isolated" should be isolated(freed)
5214 * by the balloon driver through the memory notifier chain.
5216 notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
5217 notifier_ret = notifier_to_errno(notifier_ret);
5218 if (notifier_ret || !arg.pages_found)
5221 for (iter = pfn; iter < (pfn + pageblock_nr_pages); iter++) {
5222 if (!pfn_valid_within(pfn))
5225 curr_page = pfn_to_page(iter);
5226 if (!page_count(curr_page) || PageLRU(curr_page))
5232 if (arg.pages_found == immobile)
5237 set_pageblock_migratetype(page, MIGRATE_ISOLATE);
5238 move_freepages_block(zone, page, MIGRATE_ISOLATE);
5241 spin_unlock_irqrestore(&zone->lock, flags);
5247 void unset_migratetype_isolate(struct page *page)
5250 unsigned long flags;
5251 zone = page_zone(page);
5252 spin_lock_irqsave(&zone->lock, flags);
5253 if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
5255 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5256 move_freepages_block(zone, page, MIGRATE_MOVABLE);
5258 spin_unlock_irqrestore(&zone->lock, flags);
5261 #ifdef CONFIG_MEMORY_HOTREMOVE
5263 * All pages in the range must be isolated before calling this.
5266 __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
5272 unsigned long flags;
5273 /* find the first valid pfn */
5274 for (pfn = start_pfn; pfn < end_pfn; pfn++)
5279 zone = page_zone(pfn_to_page(pfn));
5280 spin_lock_irqsave(&zone->lock, flags);
5282 while (pfn < end_pfn) {
5283 if (!pfn_valid(pfn)) {
5287 page = pfn_to_page(pfn);
5288 BUG_ON(page_count(page));
5289 BUG_ON(!PageBuddy(page));
5290 order = page_order(page);
5291 #ifdef CONFIG_DEBUG_VM
5292 printk(KERN_INFO "remove from free list %lx %d %lx\n",
5293 pfn, 1 << order, end_pfn);
5295 list_del(&page->lru);
5296 rmv_page_order(page);
5297 zone->free_area[order].nr_free--;
5298 __mod_zone_page_state(zone, NR_FREE_PAGES,
5300 for (i = 0; i < (1 << order); i++)
5301 SetPageReserved((page+i));
5302 pfn += (1 << order);
5304 spin_unlock_irqrestore(&zone->lock, flags);
5308 #ifdef CONFIG_MEMORY_FAILURE
5309 bool is_free_buddy_page(struct page *page)
5311 struct zone *zone = page_zone(page);
5312 unsigned long pfn = page_to_pfn(page);
5313 unsigned long flags;
5316 spin_lock_irqsave(&zone->lock, flags);
5317 for (order = 0; order < MAX_ORDER; order++) {
5318 struct page *page_head = page - (pfn & ((1 << order) - 1));
5320 if (PageBuddy(page_head) && page_order(page_head) >= order)
5323 spin_unlock_irqrestore(&zone->lock, flags);
5325 return order < MAX_ORDER;
5329 static struct trace_print_flags pageflag_names[] = {
5330 {1UL << PG_locked, "locked" },
5331 {1UL << PG_error, "error" },
5332 {1UL << PG_referenced, "referenced" },
5333 {1UL << PG_uptodate, "uptodate" },
5334 {1UL << PG_dirty, "dirty" },
5335 {1UL << PG_lru, "lru" },
5336 {1UL << PG_active, "active" },
5337 {1UL << PG_slab, "slab" },
5338 {1UL << PG_owner_priv_1, "owner_priv_1" },
5339 {1UL << PG_arch_1, "arch_1" },
5340 {1UL << PG_reserved, "reserved" },
5341 {1UL << PG_private, "private" },
5342 {1UL << PG_private_2, "private_2" },
5343 {1UL << PG_writeback, "writeback" },
5344 #ifdef CONFIG_PAGEFLAGS_EXTENDED
5345 {1UL << PG_head, "head" },
5346 {1UL << PG_tail, "tail" },
5348 {1UL << PG_compound, "compound" },
5350 {1UL << PG_swapcache, "swapcache" },
5351 {1UL << PG_mappedtodisk, "mappedtodisk" },
5352 {1UL << PG_reclaim, "reclaim" },
5353 {1UL << PG_buddy, "buddy" },
5354 {1UL << PG_swapbacked, "swapbacked" },
5355 {1UL << PG_unevictable, "unevictable" },
5357 {1UL << PG_mlocked, "mlocked" },
5359 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
5360 {1UL << PG_uncached, "uncached" },
5362 #ifdef CONFIG_MEMORY_FAILURE
5363 {1UL << PG_hwpoison, "hwpoison" },
5368 static void dump_page_flags(unsigned long flags)
5370 const char *delim = "";
5374 printk(KERN_ALERT "page flags: %#lx(", flags);
5376 /* remove zone id */
5377 flags &= (1UL << NR_PAGEFLAGS) - 1;
5379 for (i = 0; pageflag_names[i].name && flags; i++) {
5381 mask = pageflag_names[i].mask;
5382 if ((flags & mask) != mask)
5386 printk("%s%s", delim, pageflag_names[i].name);
5390 /* check for left over flags */
5392 printk("%s%#lx", delim, flags);
5397 void dump_page(struct page *page)
5400 "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
5401 page, page_count(page), page_mapcount(page),
5402 page->mapping, page->index);
5403 dump_page_flags(page->flags);