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/bootmem.h>
23 #include <linux/compiler.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/suspend.h>
27 #include <linux/pagevec.h>
28 #include <linux/blkdev.h>
29 #include <linux/slab.h>
30 #include <linux/notifier.h>
31 #include <linux/topology.h>
32 #include <linux/sysctl.h>
33 #include <linux/cpu.h>
34 #include <linux/cpuset.h>
35 #include <linux/memory_hotplug.h>
36 #include <linux/nodemask.h>
37 #include <linux/vmalloc.h>
38 #include <linux/mempolicy.h>
39 #include <linux/stop_machine.h>
40 #include <linux/sort.h>
41 #include <linux/pfn.h>
42 #include <linux/backing-dev.h>
43 #include <linux/fault-inject.h>
45 #include <asm/tlbflush.h>
46 #include <asm/div64.h>
50 * MCD - HACK: Find somewhere to initialize this EARLY, or make this
53 nodemask_t node_online_map __read_mostly = { { [0] = 1UL } };
54 EXPORT_SYMBOL(node_online_map);
55 nodemask_t node_possible_map __read_mostly = NODE_MASK_ALL;
56 EXPORT_SYMBOL(node_possible_map);
57 unsigned long totalram_pages __read_mostly;
58 unsigned long totalreserve_pages __read_mostly;
60 int percpu_pagelist_fraction;
62 static void __free_pages_ok(struct page *page, unsigned int order);
65 * results with 256, 32 in the lowmem_reserve sysctl:
66 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
67 * 1G machine -> (16M dma, 784M normal, 224M high)
68 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
69 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
70 * HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
72 * TBD: should special case ZONE_DMA32 machines here - in those we normally
73 * don't need any ZONE_NORMAL reservation
75 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
77 #ifdef CONFIG_ZONE_DMA32
85 EXPORT_SYMBOL(totalram_pages);
87 static char * const zone_names[MAX_NR_ZONES] = {
89 #ifdef CONFIG_ZONE_DMA32
98 int min_free_kbytes = 1024;
100 unsigned long __meminitdata nr_kernel_pages;
101 unsigned long __meminitdata nr_all_pages;
102 static unsigned long __initdata dma_reserve;
104 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
106 * MAX_ACTIVE_REGIONS determines the maxmimum number of distinct
107 * ranges of memory (RAM) that may be registered with add_active_range().
108 * Ranges passed to add_active_range() will be merged if possible
109 * so the number of times add_active_range() can be called is
110 * related to the number of nodes and the number of holes
112 #ifdef CONFIG_MAX_ACTIVE_REGIONS
113 /* Allow an architecture to set MAX_ACTIVE_REGIONS to save memory */
114 #define MAX_ACTIVE_REGIONS CONFIG_MAX_ACTIVE_REGIONS
116 #if MAX_NUMNODES >= 32
117 /* If there can be many nodes, allow up to 50 holes per node */
118 #define MAX_ACTIVE_REGIONS (MAX_NUMNODES*50)
120 /* By default, allow up to 256 distinct regions */
121 #define MAX_ACTIVE_REGIONS 256
125 struct node_active_region __initdata early_node_map[MAX_ACTIVE_REGIONS];
126 int __initdata nr_nodemap_entries;
127 unsigned long __initdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
128 unsigned long __initdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
129 #ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
130 unsigned long __initdata node_boundary_start_pfn[MAX_NUMNODES];
131 unsigned long __initdata node_boundary_end_pfn[MAX_NUMNODES];
132 #endif /* CONFIG_MEMORY_HOTPLUG_RESERVE */
133 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
135 #ifdef CONFIG_DEBUG_VM
136 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
140 unsigned long pfn = page_to_pfn(page);
143 seq = zone_span_seqbegin(zone);
144 if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
146 else if (pfn < zone->zone_start_pfn)
148 } while (zone_span_seqretry(zone, seq));
153 static int page_is_consistent(struct zone *zone, struct page *page)
155 #ifdef CONFIG_HOLES_IN_ZONE
156 if (!pfn_valid(page_to_pfn(page)))
159 if (zone != page_zone(page))
165 * Temporary debugging check for pages not lying within a given zone.
167 static int bad_range(struct zone *zone, struct page *page)
169 if (page_outside_zone_boundaries(zone, page))
171 if (!page_is_consistent(zone, page))
177 static inline int bad_range(struct zone *zone, struct page *page)
183 static void bad_page(struct page *page)
185 printk(KERN_EMERG "Bad page state in process '%s'\n"
186 KERN_EMERG "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n"
187 KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
188 KERN_EMERG "Backtrace:\n",
189 current->comm, page, (int)(2*sizeof(unsigned long)),
190 (unsigned long)page->flags, page->mapping,
191 page_mapcount(page), page_count(page));
193 page->flags &= ~(1 << PG_lru |
203 set_page_count(page, 0);
204 reset_page_mapcount(page);
205 page->mapping = NULL;
206 add_taint(TAINT_BAD_PAGE);
210 * Higher-order pages are called "compound pages". They are structured thusly:
212 * The first PAGE_SIZE page is called the "head page".
214 * The remaining PAGE_SIZE pages are called "tail pages".
216 * All pages have PG_compound set. All pages have their ->private pointing at
217 * the head page (even the head page has this).
219 * The first tail page's ->lru.next holds the address of the compound page's
220 * put_page() function. Its ->lru.prev holds the order of allocation.
221 * This usage means that zero-order pages may not be compound.
224 static void free_compound_page(struct page *page)
226 __free_pages_ok(page, (unsigned long)page[1].lru.prev);
229 static void prep_compound_page(struct page *page, unsigned long order)
232 int nr_pages = 1 << order;
234 set_compound_page_dtor(page, free_compound_page);
235 page[1].lru.prev = (void *)order;
236 for (i = 0; i < nr_pages; i++) {
237 struct page *p = page + i;
239 __SetPageCompound(p);
240 set_page_private(p, (unsigned long)page);
244 static void destroy_compound_page(struct page *page, unsigned long order)
247 int nr_pages = 1 << order;
249 if (unlikely((unsigned long)page[1].lru.prev != order))
252 for (i = 0; i < nr_pages; i++) {
253 struct page *p = page + i;
255 if (unlikely(!PageCompound(p) |
256 (page_private(p) != (unsigned long)page)))
258 __ClearPageCompound(p);
262 static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
266 VM_BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM);
268 * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
269 * and __GFP_HIGHMEM from hard or soft interrupt context.
271 VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
272 for (i = 0; i < (1 << order); i++)
273 clear_highpage(page + i);
277 * function for dealing with page's order in buddy system.
278 * zone->lock is already acquired when we use these.
279 * So, we don't need atomic page->flags operations here.
281 static inline unsigned long page_order(struct page *page)
283 return page_private(page);
286 static inline void set_page_order(struct page *page, int order)
288 set_page_private(page, order);
289 __SetPageBuddy(page);
292 static inline void rmv_page_order(struct page *page)
294 __ClearPageBuddy(page);
295 set_page_private(page, 0);
299 * Locate the struct page for both the matching buddy in our
300 * pair (buddy1) and the combined O(n+1) page they form (page).
302 * 1) Any buddy B1 will have an order O twin B2 which satisfies
303 * the following equation:
305 * For example, if the starting buddy (buddy2) is #8 its order
307 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
309 * 2) Any buddy B will have an order O+1 parent P which
310 * satisfies the following equation:
313 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
315 static inline struct page *
316 __page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
318 unsigned long buddy_idx = page_idx ^ (1 << order);
320 return page + (buddy_idx - page_idx);
323 static inline unsigned long
324 __find_combined_index(unsigned long page_idx, unsigned int order)
326 return (page_idx & ~(1 << order));
330 * This function checks whether a page is free && is the buddy
331 * we can do coalesce a page and its buddy if
332 * (a) the buddy is not in a hole &&
333 * (b) the buddy is in the buddy system &&
334 * (c) a page and its buddy have the same order &&
335 * (d) a page and its buddy are in the same zone.
337 * For recording whether a page is in the buddy system, we use PG_buddy.
338 * Setting, clearing, and testing PG_buddy is serialized by zone->lock.
340 * For recording page's order, we use page_private(page).
342 static inline int page_is_buddy(struct page *page, struct page *buddy,
345 #ifdef CONFIG_HOLES_IN_ZONE
346 if (!pfn_valid(page_to_pfn(buddy)))
350 if (page_zone_id(page) != page_zone_id(buddy))
353 if (PageBuddy(buddy) && page_order(buddy) == order) {
354 BUG_ON(page_count(buddy) != 0);
361 * Freeing function for a buddy system allocator.
363 * The concept of a buddy system is to maintain direct-mapped table
364 * (containing bit values) for memory blocks of various "orders".
365 * The bottom level table contains the map for the smallest allocatable
366 * units of memory (here, pages), and each level above it describes
367 * pairs of units from the levels below, hence, "buddies".
368 * At a high level, all that happens here is marking the table entry
369 * at the bottom level available, and propagating the changes upward
370 * as necessary, plus some accounting needed to play nicely with other
371 * parts of the VM system.
372 * At each level, we keep a list of pages, which are heads of continuous
373 * free pages of length of (1 << order) and marked with PG_buddy. Page's
374 * order is recorded in page_private(page) field.
375 * So when we are allocating or freeing one, we can derive the state of the
376 * other. That is, if we allocate a small block, and both were
377 * free, the remainder of the region must be split into blocks.
378 * If a block is freed, and its buddy is also free, then this
379 * triggers coalescing into a block of larger size.
384 static inline void __free_one_page(struct page *page,
385 struct zone *zone, unsigned int order)
387 unsigned long page_idx;
388 int order_size = 1 << order;
390 if (unlikely(PageCompound(page)))
391 destroy_compound_page(page, order);
393 page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
395 VM_BUG_ON(page_idx & (order_size - 1));
396 VM_BUG_ON(bad_range(zone, page));
398 __mod_zone_page_state(zone, NR_FREE_PAGES, order_size);
399 while (order < MAX_ORDER-1) {
400 unsigned long combined_idx;
401 struct free_area *area;
404 buddy = __page_find_buddy(page, page_idx, order);
405 if (!page_is_buddy(page, buddy, order))
406 break; /* Move the buddy up one level. */
408 list_del(&buddy->lru);
409 area = zone->free_area + order;
411 rmv_page_order(buddy);
412 combined_idx = __find_combined_index(page_idx, order);
413 page = page + (combined_idx - page_idx);
414 page_idx = combined_idx;
417 set_page_order(page, order);
418 list_add(&page->lru, &zone->free_area[order].free_list);
419 zone->free_area[order].nr_free++;
422 static inline int free_pages_check(struct page *page)
424 if (unlikely(page_mapcount(page) |
425 (page->mapping != NULL) |
426 (page_count(page) != 0) |
440 __ClearPageDirty(page);
442 * For now, we report if PG_reserved was found set, but do not
443 * clear it, and do not free the page. But we shall soon need
444 * to do more, for when the ZERO_PAGE count wraps negative.
446 return PageReserved(page);
450 * Frees a list of pages.
451 * Assumes all pages on list are in same zone, and of same order.
452 * count is the number of pages to free.
454 * If the zone was previously in an "all pages pinned" state then look to
455 * see if this freeing clears that state.
457 * And clear the zone's pages_scanned counter, to hold off the "all pages are
458 * pinned" detection logic.
460 static void free_pages_bulk(struct zone *zone, int count,
461 struct list_head *list, int order)
463 spin_lock(&zone->lock);
464 zone->all_unreclaimable = 0;
465 zone->pages_scanned = 0;
469 VM_BUG_ON(list_empty(list));
470 page = list_entry(list->prev, struct page, lru);
471 /* have to delete it as __free_one_page list manipulates */
472 list_del(&page->lru);
473 __free_one_page(page, zone, order);
475 spin_unlock(&zone->lock);
478 static void free_one_page(struct zone *zone, struct page *page, int order)
480 spin_lock(&zone->lock);
481 zone->all_unreclaimable = 0;
482 zone->pages_scanned = 0;
483 __free_one_page(page, zone, order);
484 spin_unlock(&zone->lock);
487 static void __free_pages_ok(struct page *page, unsigned int order)
493 for (i = 0 ; i < (1 << order) ; ++i)
494 reserved += free_pages_check(page + i);
498 if (!PageHighMem(page))
499 debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
500 arch_free_page(page, order);
501 kernel_map_pages(page, 1 << order, 0);
503 local_irq_save(flags);
504 __count_vm_events(PGFREE, 1 << order);
505 free_one_page(page_zone(page), page, order);
506 local_irq_restore(flags);
510 * permit the bootmem allocator to evade page validation on high-order frees
512 void fastcall __init __free_pages_bootmem(struct page *page, unsigned int order)
515 __ClearPageReserved(page);
516 set_page_count(page, 0);
517 set_page_refcounted(page);
523 for (loop = 0; loop < BITS_PER_LONG; loop++) {
524 struct page *p = &page[loop];
526 if (loop + 1 < BITS_PER_LONG)
528 __ClearPageReserved(p);
529 set_page_count(p, 0);
532 set_page_refcounted(page);
533 __free_pages(page, order);
539 * The order of subdivision here is critical for the IO subsystem.
540 * Please do not alter this order without good reasons and regression
541 * testing. Specifically, as large blocks of memory are subdivided,
542 * the order in which smaller blocks are delivered depends on the order
543 * they're subdivided in this function. This is the primary factor
544 * influencing the order in which pages are delivered to the IO
545 * subsystem according to empirical testing, and this is also justified
546 * by considering the behavior of a buddy system containing a single
547 * large block of memory acted on by a series of small allocations.
548 * This behavior is a critical factor in sglist merging's success.
552 static inline void expand(struct zone *zone, struct page *page,
553 int low, int high, struct free_area *area)
555 unsigned long size = 1 << high;
561 VM_BUG_ON(bad_range(zone, &page[size]));
562 list_add(&page[size].lru, &area->free_list);
564 set_page_order(&page[size], high);
569 * This page is about to be returned from the page allocator
571 static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
573 if (unlikely(page_mapcount(page) |
574 (page->mapping != NULL) |
575 (page_count(page) != 0) |
591 * For now, we report if PG_reserved was found set, but do not
592 * clear it, and do not allocate the page: as a safety net.
594 if (PageReserved(page))
597 page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
598 1 << PG_referenced | 1 << PG_arch_1 |
599 1 << PG_checked | 1 << PG_mappedtodisk);
600 set_page_private(page, 0);
601 set_page_refcounted(page);
603 arch_alloc_page(page, order);
604 kernel_map_pages(page, 1 << order, 1);
606 if (gfp_flags & __GFP_ZERO)
607 prep_zero_page(page, order, gfp_flags);
609 if (order && (gfp_flags & __GFP_COMP))
610 prep_compound_page(page, order);
616 * Do the hard work of removing an element from the buddy allocator.
617 * Call me with the zone->lock already held.
619 static struct page *__rmqueue(struct zone *zone, unsigned int order)
621 struct free_area * area;
622 unsigned int current_order;
625 for (current_order = order; current_order < MAX_ORDER; ++current_order) {
626 area = zone->free_area + current_order;
627 if (list_empty(&area->free_list))
630 page = list_entry(area->free_list.next, struct page, lru);
631 list_del(&page->lru);
632 rmv_page_order(page);
634 __mod_zone_page_state(zone, NR_FREE_PAGES, - (1UL << order));
635 expand(zone, page, order, current_order, area);
643 * Obtain a specified number of elements from the buddy allocator, all under
644 * a single hold of the lock, for efficiency. Add them to the supplied list.
645 * Returns the number of new pages which were placed at *list.
647 static int rmqueue_bulk(struct zone *zone, unsigned int order,
648 unsigned long count, struct list_head *list)
652 spin_lock(&zone->lock);
653 for (i = 0; i < count; ++i) {
654 struct page *page = __rmqueue(zone, order);
655 if (unlikely(page == NULL))
657 list_add_tail(&page->lru, list);
659 spin_unlock(&zone->lock);
665 * Called from the slab reaper to drain pagesets on a particular node that
666 * belongs to the currently executing processor.
667 * Note that this function must be called with the thread pinned to
668 * a single processor.
670 void drain_node_pages(int nodeid)
676 for (z = 0; z < MAX_NR_ZONES; z++) {
677 struct zone *zone = NODE_DATA(nodeid)->node_zones + z;
678 struct per_cpu_pageset *pset;
680 if (!populated_zone(zone))
683 pset = zone_pcp(zone, smp_processor_id());
684 for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
685 struct per_cpu_pages *pcp;
691 local_irq_save(flags);
692 if (pcp->count >= pcp->batch)
693 to_drain = pcp->batch;
695 to_drain = pcp->count;
696 free_pages_bulk(zone, to_drain, &pcp->list, 0);
697 pcp->count -= to_drain;
698 local_irq_restore(flags);
705 static void __drain_pages(unsigned int cpu)
711 for_each_zone(zone) {
712 struct per_cpu_pageset *pset;
714 if (!populated_zone(zone))
717 pset = zone_pcp(zone, cpu);
718 for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
719 struct per_cpu_pages *pcp;
722 local_irq_save(flags);
723 free_pages_bulk(zone, pcp->count, &pcp->list, 0);
725 local_irq_restore(flags);
732 void mark_free_pages(struct zone *zone)
734 unsigned long pfn, max_zone_pfn;
737 struct list_head *curr;
739 if (!zone->spanned_pages)
742 spin_lock_irqsave(&zone->lock, flags);
744 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
745 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
746 if (pfn_valid(pfn)) {
747 struct page *page = pfn_to_page(pfn);
749 if (!PageNosave(page))
750 ClearPageNosaveFree(page);
753 for (order = MAX_ORDER - 1; order >= 0; --order)
754 list_for_each(curr, &zone->free_area[order].free_list) {
757 pfn = page_to_pfn(list_entry(curr, struct page, lru));
758 for (i = 0; i < (1UL << order); i++)
759 SetPageNosaveFree(pfn_to_page(pfn + i));
762 spin_unlock_irqrestore(&zone->lock, flags);
766 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
768 void drain_local_pages(void)
772 local_irq_save(flags);
773 __drain_pages(smp_processor_id());
774 local_irq_restore(flags);
776 #endif /* CONFIG_PM */
779 * Free a 0-order page
781 static void fastcall free_hot_cold_page(struct page *page, int cold)
783 struct zone *zone = page_zone(page);
784 struct per_cpu_pages *pcp;
788 page->mapping = NULL;
789 if (free_pages_check(page))
792 if (!PageHighMem(page))
793 debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
794 arch_free_page(page, 0);
795 kernel_map_pages(page, 1, 0);
797 pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
798 local_irq_save(flags);
799 __count_vm_event(PGFREE);
800 list_add(&page->lru, &pcp->list);
802 if (pcp->count >= pcp->high) {
803 free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
804 pcp->count -= pcp->batch;
806 local_irq_restore(flags);
810 void fastcall free_hot_page(struct page *page)
812 free_hot_cold_page(page, 0);
815 void fastcall free_cold_page(struct page *page)
817 free_hot_cold_page(page, 1);
821 * split_page takes a non-compound higher-order page, and splits it into
822 * n (1<<order) sub-pages: page[0..n]
823 * Each sub-page must be freed individually.
825 * Note: this is probably too low level an operation for use in drivers.
826 * Please consult with lkml before using this in your driver.
828 void split_page(struct page *page, unsigned int order)
832 VM_BUG_ON(PageCompound(page));
833 VM_BUG_ON(!page_count(page));
834 for (i = 1; i < (1 << order); i++)
835 set_page_refcounted(page + i);
839 * Really, prep_compound_page() should be called from __rmqueue_bulk(). But
840 * we cheat by calling it from here, in the order > 0 path. Saves a branch
843 static struct page *buffered_rmqueue(struct zonelist *zonelist,
844 struct zone *zone, int order, gfp_t gfp_flags)
848 int cold = !!(gfp_flags & __GFP_COLD);
853 if (likely(order == 0)) {
854 struct per_cpu_pages *pcp;
856 pcp = &zone_pcp(zone, cpu)->pcp[cold];
857 local_irq_save(flags);
859 pcp->count = rmqueue_bulk(zone, 0,
860 pcp->batch, &pcp->list);
861 if (unlikely(!pcp->count))
864 page = list_entry(pcp->list.next, struct page, lru);
865 list_del(&page->lru);
868 spin_lock_irqsave(&zone->lock, flags);
869 page = __rmqueue(zone, order);
870 spin_unlock(&zone->lock);
875 __count_zone_vm_events(PGALLOC, zone, 1 << order);
876 zone_statistics(zonelist, zone);
877 local_irq_restore(flags);
880 VM_BUG_ON(bad_range(zone, page));
881 if (prep_new_page(page, order, gfp_flags))
886 local_irq_restore(flags);
891 #define ALLOC_NO_WATERMARKS 0x01 /* don't check watermarks at all */
892 #define ALLOC_WMARK_MIN 0x02 /* use pages_min watermark */
893 #define ALLOC_WMARK_LOW 0x04 /* use pages_low watermark */
894 #define ALLOC_WMARK_HIGH 0x08 /* use pages_high watermark */
895 #define ALLOC_HARDER 0x10 /* try to alloc harder */
896 #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
897 #define ALLOC_CPUSET 0x40 /* check for correct cpuset */
899 #ifdef CONFIG_FAIL_PAGE_ALLOC
901 static struct fail_page_alloc_attr {
902 struct fault_attr attr;
904 u32 ignore_gfp_highmem;
907 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
909 struct dentry *ignore_gfp_highmem_file;
910 struct dentry *ignore_gfp_wait_file;
912 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
914 } fail_page_alloc = {
915 .attr = FAULT_ATTR_INITIALIZER,
916 .ignore_gfp_wait = 1,
917 .ignore_gfp_highmem = 1,
920 static int __init setup_fail_page_alloc(char *str)
922 return setup_fault_attr(&fail_page_alloc.attr, str);
924 __setup("fail_page_alloc=", setup_fail_page_alloc);
926 static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
928 if (gfp_mask & __GFP_NOFAIL)
930 if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
932 if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
935 return should_fail(&fail_page_alloc.attr, 1 << order);
938 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
940 static int __init fail_page_alloc_debugfs(void)
942 mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
946 err = init_fault_attr_dentries(&fail_page_alloc.attr,
950 dir = fail_page_alloc.attr.dentries.dir;
952 fail_page_alloc.ignore_gfp_wait_file =
953 debugfs_create_bool("ignore-gfp-wait", mode, dir,
954 &fail_page_alloc.ignore_gfp_wait);
956 fail_page_alloc.ignore_gfp_highmem_file =
957 debugfs_create_bool("ignore-gfp-highmem", mode, dir,
958 &fail_page_alloc.ignore_gfp_highmem);
960 if (!fail_page_alloc.ignore_gfp_wait_file ||
961 !fail_page_alloc.ignore_gfp_highmem_file) {
963 debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
964 debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
965 cleanup_fault_attr_dentries(&fail_page_alloc.attr);
971 late_initcall(fail_page_alloc_debugfs);
973 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
975 #else /* CONFIG_FAIL_PAGE_ALLOC */
977 static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
982 #endif /* CONFIG_FAIL_PAGE_ALLOC */
985 * Return 1 if free pages are above 'mark'. This takes into account the order
988 int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
989 int classzone_idx, int alloc_flags)
991 /* free_pages my go negative - that's OK */
993 long free_pages = zone_page_state(z, NR_FREE_PAGES) - (1 << order) + 1;
996 if (alloc_flags & ALLOC_HIGH)
998 if (alloc_flags & ALLOC_HARDER)
1001 if (free_pages <= min + z->lowmem_reserve[classzone_idx])
1003 for (o = 0; o < order; o++) {
1004 /* At the next order, this order's pages become unavailable */
1005 free_pages -= z->free_area[o].nr_free << o;
1007 /* Require fewer higher order pages to be free */
1010 if (free_pages <= min)
1018 * zlc_setup - Setup for "zonelist cache". Uses cached zone data to
1019 * skip over zones that are not allowed by the cpuset, or that have
1020 * been recently (in last second) found to be nearly full. See further
1021 * comments in mmzone.h. Reduces cache footprint of zonelist scans
1022 * that have to skip over alot of full or unallowed zones.
1024 * If the zonelist cache is present in the passed in zonelist, then
1025 * returns a pointer to the allowed node mask (either the current
1026 * tasks mems_allowed, or node_online_map.)
1028 * If the zonelist cache is not available for this zonelist, does
1029 * nothing and returns NULL.
1031 * If the fullzones BITMAP in the zonelist cache is stale (more than
1032 * a second since last zap'd) then we zap it out (clear its bits.)
1034 * We hold off even calling zlc_setup, until after we've checked the
1035 * first zone in the zonelist, on the theory that most allocations will
1036 * be satisfied from that first zone, so best to examine that zone as
1037 * quickly as we can.
1039 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1041 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1042 nodemask_t *allowednodes; /* zonelist_cache approximation */
1044 zlc = zonelist->zlcache_ptr;
1048 if (jiffies - zlc->last_full_zap > 1 * HZ) {
1049 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1050 zlc->last_full_zap = jiffies;
1053 allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1054 &cpuset_current_mems_allowed :
1056 return allowednodes;
1060 * Given 'z' scanning a zonelist, run a couple of quick checks to see
1061 * if it is worth looking at further for free memory:
1062 * 1) Check that the zone isn't thought to be full (doesn't have its
1063 * bit set in the zonelist_cache fullzones BITMAP).
1064 * 2) Check that the zones node (obtained from the zonelist_cache
1065 * z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1066 * Return true (non-zero) if zone is worth looking at further, or
1067 * else return false (zero) if it is not.
1069 * This check -ignores- the distinction between various watermarks,
1070 * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ... If a zone is
1071 * found to be full for any variation of these watermarks, it will
1072 * be considered full for up to one second by all requests, unless
1073 * we are so low on memory on all allowed nodes that we are forced
1074 * into the second scan of the zonelist.
1076 * In the second scan we ignore this zonelist cache and exactly
1077 * apply the watermarks to all zones, even it is slower to do so.
1078 * We are low on memory in the second scan, and should leave no stone
1079 * unturned looking for a free page.
1081 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zone **z,
1082 nodemask_t *allowednodes)
1084 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1085 int i; /* index of *z in zonelist zones */
1086 int n; /* node that zone *z is on */
1088 zlc = zonelist->zlcache_ptr;
1092 i = z - zonelist->zones;
1095 /* This zone is worth trying if it is allowed but not full */
1096 return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1100 * Given 'z' scanning a zonelist, set the corresponding bit in
1101 * zlc->fullzones, so that subsequent attempts to allocate a page
1102 * from that zone don't waste time re-examining it.
1104 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zone **z)
1106 struct zonelist_cache *zlc; /* cached zonelist speedup info */
1107 int i; /* index of *z in zonelist zones */
1109 zlc = zonelist->zlcache_ptr;
1113 i = z - zonelist->zones;
1115 set_bit(i, zlc->fullzones);
1118 #else /* CONFIG_NUMA */
1120 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1125 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zone **z,
1126 nodemask_t *allowednodes)
1131 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zone **z)
1134 #endif /* CONFIG_NUMA */
1137 * get_page_from_freelist goes through the zonelist trying to allocate
1140 static struct page *
1141 get_page_from_freelist(gfp_t gfp_mask, unsigned int order,
1142 struct zonelist *zonelist, int alloc_flags)
1145 struct page *page = NULL;
1146 int classzone_idx = zone_idx(zonelist->zones[0]);
1148 nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1149 int zlc_active = 0; /* set if using zonelist_cache */
1150 int did_zlc_setup = 0; /* just call zlc_setup() one time */
1154 * Scan zonelist, looking for a zone with enough free.
1155 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1157 z = zonelist->zones;
1160 if (NUMA_BUILD && zlc_active &&
1161 !zlc_zone_worth_trying(zonelist, z, allowednodes))
1164 if (unlikely(NUMA_BUILD && (gfp_mask & __GFP_THISNODE) &&
1165 zone->zone_pgdat != zonelist->zones[0]->zone_pgdat))
1167 if ((alloc_flags & ALLOC_CPUSET) &&
1168 !cpuset_zone_allowed_softwall(zone, gfp_mask))
1171 if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
1173 if (alloc_flags & ALLOC_WMARK_MIN)
1174 mark = zone->pages_min;
1175 else if (alloc_flags & ALLOC_WMARK_LOW)
1176 mark = zone->pages_low;
1178 mark = zone->pages_high;
1179 if (!zone_watermark_ok(zone, order, mark,
1180 classzone_idx, alloc_flags)) {
1181 if (!zone_reclaim_mode ||
1182 !zone_reclaim(zone, gfp_mask, order))
1183 goto this_zone_full;
1187 page = buffered_rmqueue(zonelist, zone, order, gfp_mask);
1192 zlc_mark_zone_full(zonelist, z);
1194 if (NUMA_BUILD && !did_zlc_setup) {
1195 /* we do zlc_setup after the first zone is tried */
1196 allowednodes = zlc_setup(zonelist, alloc_flags);
1200 } while (*(++z) != NULL);
1202 if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
1203 /* Disable zlc cache for second zonelist scan */
1211 * This is the 'heart' of the zoned buddy allocator.
1213 struct page * fastcall
1214 __alloc_pages(gfp_t gfp_mask, unsigned int order,
1215 struct zonelist *zonelist)
1217 const gfp_t wait = gfp_mask & __GFP_WAIT;
1220 struct reclaim_state reclaim_state;
1221 struct task_struct *p = current;
1224 int did_some_progress;
1226 might_sleep_if(wait);
1228 if (should_fail_alloc_page(gfp_mask, order))
1232 z = zonelist->zones; /* the list of zones suitable for gfp_mask */
1234 if (unlikely(*z == NULL)) {
1235 /* Should this ever happen?? */
1239 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
1240 zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET);
1245 * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
1246 * __GFP_NOWARN set) should not cause reclaim since the subsystem
1247 * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
1248 * using a larger set of nodes after it has established that the
1249 * allowed per node queues are empty and that nodes are
1252 if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
1255 for (z = zonelist->zones; *z; z++)
1256 wakeup_kswapd(*z, order);
1259 * OK, we're below the kswapd watermark and have kicked background
1260 * reclaim. Now things get more complex, so set up alloc_flags according
1261 * to how we want to proceed.
1263 * The caller may dip into page reserves a bit more if the caller
1264 * cannot run direct reclaim, or if the caller has realtime scheduling
1265 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
1266 * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
1268 alloc_flags = ALLOC_WMARK_MIN;
1269 if ((unlikely(rt_task(p)) && !in_interrupt()) || !wait)
1270 alloc_flags |= ALLOC_HARDER;
1271 if (gfp_mask & __GFP_HIGH)
1272 alloc_flags |= ALLOC_HIGH;
1274 alloc_flags |= ALLOC_CPUSET;
1277 * Go through the zonelist again. Let __GFP_HIGH and allocations
1278 * coming from realtime tasks go deeper into reserves.
1280 * This is the last chance, in general, before the goto nopage.
1281 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
1282 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1284 page = get_page_from_freelist(gfp_mask, order, zonelist, alloc_flags);
1288 /* This allocation should allow future memory freeing. */
1291 if (((p->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE)))
1292 && !in_interrupt()) {
1293 if (!(gfp_mask & __GFP_NOMEMALLOC)) {
1295 /* go through the zonelist yet again, ignoring mins */
1296 page = get_page_from_freelist(gfp_mask, order,
1297 zonelist, ALLOC_NO_WATERMARKS);
1300 if (gfp_mask & __GFP_NOFAIL) {
1301 congestion_wait(WRITE, HZ/50);
1308 /* Atomic allocations - we can't balance anything */
1314 /* We now go into synchronous reclaim */
1315 cpuset_memory_pressure_bump();
1316 p->flags |= PF_MEMALLOC;
1317 reclaim_state.reclaimed_slab = 0;
1318 p->reclaim_state = &reclaim_state;
1320 did_some_progress = try_to_free_pages(zonelist->zones, gfp_mask);
1322 p->reclaim_state = NULL;
1323 p->flags &= ~PF_MEMALLOC;
1327 if (likely(did_some_progress)) {
1328 page = get_page_from_freelist(gfp_mask, order,
1329 zonelist, alloc_flags);
1332 } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
1334 * Go through the zonelist yet one more time, keep
1335 * very high watermark here, this is only to catch
1336 * a parallel oom killing, we must fail if we're still
1337 * under heavy pressure.
1339 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
1340 zonelist, ALLOC_WMARK_HIGH|ALLOC_CPUSET);
1344 out_of_memory(zonelist, gfp_mask, order);
1349 * Don't let big-order allocations loop unless the caller explicitly
1350 * requests that. Wait for some write requests to complete then retry.
1352 * In this implementation, __GFP_REPEAT means __GFP_NOFAIL for order
1353 * <= 3, but that may not be true in other implementations.
1356 if (!(gfp_mask & __GFP_NORETRY)) {
1357 if ((order <= 3) || (gfp_mask & __GFP_REPEAT))
1359 if (gfp_mask & __GFP_NOFAIL)
1363 congestion_wait(WRITE, HZ/50);
1368 if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
1369 printk(KERN_WARNING "%s: page allocation failure."
1370 " order:%d, mode:0x%x\n",
1371 p->comm, order, gfp_mask);
1379 EXPORT_SYMBOL(__alloc_pages);
1382 * Common helper functions.
1384 fastcall unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
1387 page = alloc_pages(gfp_mask, order);
1390 return (unsigned long) page_address(page);
1393 EXPORT_SYMBOL(__get_free_pages);
1395 fastcall unsigned long get_zeroed_page(gfp_t gfp_mask)
1400 * get_zeroed_page() returns a 32-bit address, which cannot represent
1403 VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
1405 page = alloc_pages(gfp_mask | __GFP_ZERO, 0);
1407 return (unsigned long) page_address(page);
1411 EXPORT_SYMBOL(get_zeroed_page);
1413 void __pagevec_free(struct pagevec *pvec)
1415 int i = pagevec_count(pvec);
1418 free_hot_cold_page(pvec->pages[i], pvec->cold);
1421 fastcall void __free_pages(struct page *page, unsigned int order)
1423 if (put_page_testzero(page)) {
1425 free_hot_page(page);
1427 __free_pages_ok(page, order);
1431 EXPORT_SYMBOL(__free_pages);
1433 fastcall void free_pages(unsigned long addr, unsigned int order)
1436 VM_BUG_ON(!virt_addr_valid((void *)addr));
1437 __free_pages(virt_to_page((void *)addr), order);
1441 EXPORT_SYMBOL(free_pages);
1444 * Total amount of free (allocatable) RAM:
1446 unsigned int nr_free_pages(void)
1448 return global_page_state(NR_FREE_PAGES);
1451 EXPORT_SYMBOL(nr_free_pages);
1454 unsigned int nr_free_pages_pgdat(pg_data_t *pgdat)
1456 return node_page_state(pgdat->node_id, NR_FREE_PAGES);
1460 static unsigned int nr_free_zone_pages(int offset)
1462 /* Just pick one node, since fallback list is circular */
1463 pg_data_t *pgdat = NODE_DATA(numa_node_id());
1464 unsigned int sum = 0;
1466 struct zonelist *zonelist = pgdat->node_zonelists + offset;
1467 struct zone **zonep = zonelist->zones;
1470 for (zone = *zonep++; zone; zone = *zonep++) {
1471 unsigned long size = zone->present_pages;
1472 unsigned long high = zone->pages_high;
1481 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
1483 unsigned int nr_free_buffer_pages(void)
1485 return nr_free_zone_pages(gfp_zone(GFP_USER));
1489 * Amount of free RAM allocatable within all zones
1491 unsigned int nr_free_pagecache_pages(void)
1493 return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER));
1496 static inline void show_node(struct zone *zone)
1499 printk("Node %d ", zone_to_nid(zone));
1502 void si_meminfo(struct sysinfo *val)
1504 val->totalram = totalram_pages;
1506 val->freeram = global_page_state(NR_FREE_PAGES);
1507 val->bufferram = nr_blockdev_pages();
1508 val->totalhigh = totalhigh_pages;
1509 val->freehigh = nr_free_highpages();
1510 val->mem_unit = PAGE_SIZE;
1513 EXPORT_SYMBOL(si_meminfo);
1516 void si_meminfo_node(struct sysinfo *val, int nid)
1518 pg_data_t *pgdat = NODE_DATA(nid);
1520 val->totalram = pgdat->node_present_pages;
1521 val->freeram = node_page_state(nid, NR_FREE_PAGES);
1522 #ifdef CONFIG_HIGHMEM
1523 val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
1524 val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
1530 val->mem_unit = PAGE_SIZE;
1534 #define K(x) ((x) << (PAGE_SHIFT-10))
1537 * Show free area list (used inside shift_scroll-lock stuff)
1538 * We also calculate the percentage fragmentation. We do this by counting the
1539 * memory on each free list with the exception of the first item on the list.
1541 void show_free_areas(void)
1544 unsigned long active;
1545 unsigned long inactive;
1549 for_each_zone(zone) {
1550 if (!populated_zone(zone))
1554 printk("%s per-cpu:\n", zone->name);
1556 for_each_online_cpu(cpu) {
1557 struct per_cpu_pageset *pageset;
1559 pageset = zone_pcp(zone, cpu);
1561 printk("CPU %4d: Hot: hi:%5d, btch:%4d usd:%4d "
1562 "Cold: hi:%5d, btch:%4d usd:%4d\n",
1563 cpu, pageset->pcp[0].high,
1564 pageset->pcp[0].batch, pageset->pcp[0].count,
1565 pageset->pcp[1].high, pageset->pcp[1].batch,
1566 pageset->pcp[1].count);
1570 get_zone_counts(&active, &inactive, &free);
1572 printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu unstable:%lu\n"
1573 " free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n",
1576 global_page_state(NR_FILE_DIRTY),
1577 global_page_state(NR_WRITEBACK),
1578 global_page_state(NR_UNSTABLE_NFS),
1579 global_page_state(NR_FREE_PAGES),
1580 global_page_state(NR_SLAB_RECLAIMABLE) +
1581 global_page_state(NR_SLAB_UNRECLAIMABLE),
1582 global_page_state(NR_FILE_MAPPED),
1583 global_page_state(NR_PAGETABLE),
1584 global_page_state(NR_BOUNCE));
1586 for_each_zone(zone) {
1589 if (!populated_zone(zone))
1601 " pages_scanned:%lu"
1602 " all_unreclaimable? %s"
1605 K(zone_page_state(zone, NR_FREE_PAGES)),
1608 K(zone->pages_high),
1609 K(zone_page_state(zone, NR_ACTIVE)),
1610 K(zone_page_state(zone, NR_INACTIVE)),
1611 K(zone->present_pages),
1612 zone->pages_scanned,
1613 (zone->all_unreclaimable ? "yes" : "no")
1615 printk("lowmem_reserve[]:");
1616 for (i = 0; i < MAX_NR_ZONES; i++)
1617 printk(" %lu", zone->lowmem_reserve[i]);
1621 for_each_zone(zone) {
1622 unsigned long nr[MAX_ORDER], flags, order, total = 0;
1624 if (!populated_zone(zone))
1628 printk("%s: ", zone->name);
1630 spin_lock_irqsave(&zone->lock, flags);
1631 for (order = 0; order < MAX_ORDER; order++) {
1632 nr[order] = zone->free_area[order].nr_free;
1633 total += nr[order] << order;
1635 spin_unlock_irqrestore(&zone->lock, flags);
1636 for (order = 0; order < MAX_ORDER; order++)
1637 printk("%lu*%lukB ", nr[order], K(1UL) << order);
1638 printk("= %lukB\n", K(total));
1641 show_swap_cache_info();
1645 * Builds allocation fallback zone lists.
1647 * Add all populated zones of a node to the zonelist.
1649 static int __meminit build_zonelists_node(pg_data_t *pgdat,
1650 struct zonelist *zonelist, int nr_zones, enum zone_type zone_type)
1654 BUG_ON(zone_type >= MAX_NR_ZONES);
1659 zone = pgdat->node_zones + zone_type;
1660 if (populated_zone(zone)) {
1661 zonelist->zones[nr_zones++] = zone;
1662 check_highest_zone(zone_type);
1665 } while (zone_type);
1670 #define MAX_NODE_LOAD (num_online_nodes())
1671 static int __meminitdata node_load[MAX_NUMNODES];
1673 * find_next_best_node - find the next node that should appear in a given node's fallback list
1674 * @node: node whose fallback list we're appending
1675 * @used_node_mask: nodemask_t of already used nodes
1677 * We use a number of factors to determine which is the next node that should
1678 * appear on a given node's fallback list. The node should not have appeared
1679 * already in @node's fallback list, and it should be the next closest node
1680 * according to the distance array (which contains arbitrary distance values
1681 * from each node to each node in the system), and should also prefer nodes
1682 * with no CPUs, since presumably they'll have very little allocation pressure
1683 * on them otherwise.
1684 * It returns -1 if no node is found.
1686 static int __meminit find_next_best_node(int node, nodemask_t *used_node_mask)
1689 int min_val = INT_MAX;
1692 /* Use the local node if we haven't already */
1693 if (!node_isset(node, *used_node_mask)) {
1694 node_set(node, *used_node_mask);
1698 for_each_online_node(n) {
1701 /* Don't want a node to appear more than once */
1702 if (node_isset(n, *used_node_mask))
1705 /* Use the distance array to find the distance */
1706 val = node_distance(node, n);
1708 /* Penalize nodes under us ("prefer the next node") */
1711 /* Give preference to headless and unused nodes */
1712 tmp = node_to_cpumask(n);
1713 if (!cpus_empty(tmp))
1714 val += PENALTY_FOR_NODE_WITH_CPUS;
1716 /* Slight preference for less loaded node */
1717 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
1718 val += node_load[n];
1720 if (val < min_val) {
1727 node_set(best_node, *used_node_mask);
1732 static void __meminit build_zonelists(pg_data_t *pgdat)
1734 int j, node, local_node;
1736 int prev_node, load;
1737 struct zonelist *zonelist;
1738 nodemask_t used_mask;
1740 /* initialize zonelists */
1741 for (i = 0; i < MAX_NR_ZONES; i++) {
1742 zonelist = pgdat->node_zonelists + i;
1743 zonelist->zones[0] = NULL;
1746 /* NUMA-aware ordering of nodes */
1747 local_node = pgdat->node_id;
1748 load = num_online_nodes();
1749 prev_node = local_node;
1750 nodes_clear(used_mask);
1751 while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
1752 int distance = node_distance(local_node, node);
1755 * If another node is sufficiently far away then it is better
1756 * to reclaim pages in a zone before going off node.
1758 if (distance > RECLAIM_DISTANCE)
1759 zone_reclaim_mode = 1;
1762 * We don't want to pressure a particular node.
1763 * So adding penalty to the first node in same
1764 * distance group to make it round-robin.
1767 if (distance != node_distance(local_node, prev_node))
1768 node_load[node] += load;
1771 for (i = 0; i < MAX_NR_ZONES; i++) {
1772 zonelist = pgdat->node_zonelists + i;
1773 for (j = 0; zonelist->zones[j] != NULL; j++);
1775 j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
1776 zonelist->zones[j] = NULL;
1781 /* Construct the zonelist performance cache - see further mmzone.h */
1782 static void __meminit build_zonelist_cache(pg_data_t *pgdat)
1786 for (i = 0; i < MAX_NR_ZONES; i++) {
1787 struct zonelist *zonelist;
1788 struct zonelist_cache *zlc;
1791 zonelist = pgdat->node_zonelists + i;
1792 zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
1793 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1794 for (z = zonelist->zones; *z; z++)
1795 zlc->z_to_n[z - zonelist->zones] = zone_to_nid(*z);
1799 #else /* CONFIG_NUMA */
1801 static void __meminit build_zonelists(pg_data_t *pgdat)
1803 int node, local_node;
1806 local_node = pgdat->node_id;
1807 for (i = 0; i < MAX_NR_ZONES; i++) {
1808 struct zonelist *zonelist;
1810 zonelist = pgdat->node_zonelists + i;
1812 j = build_zonelists_node(pgdat, zonelist, 0, i);
1814 * Now we build the zonelist so that it contains the zones
1815 * of all the other nodes.
1816 * We don't want to pressure a particular node, so when
1817 * building the zones for node N, we make sure that the
1818 * zones coming right after the local ones are those from
1819 * node N+1 (modulo N)
1821 for (node = local_node + 1; node < MAX_NUMNODES; node++) {
1822 if (!node_online(node))
1824 j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
1826 for (node = 0; node < local_node; node++) {
1827 if (!node_online(node))
1829 j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
1832 zonelist->zones[j] = NULL;
1836 /* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
1837 static void __meminit build_zonelist_cache(pg_data_t *pgdat)
1841 for (i = 0; i < MAX_NR_ZONES; i++)
1842 pgdat->node_zonelists[i].zlcache_ptr = NULL;
1845 #endif /* CONFIG_NUMA */
1847 /* return values int ....just for stop_machine_run() */
1848 static int __meminit __build_all_zonelists(void *dummy)
1852 for_each_online_node(nid) {
1853 build_zonelists(NODE_DATA(nid));
1854 build_zonelist_cache(NODE_DATA(nid));
1859 void __meminit build_all_zonelists(void)
1861 if (system_state == SYSTEM_BOOTING) {
1862 __build_all_zonelists(NULL);
1863 cpuset_init_current_mems_allowed();
1865 /* we have to stop all cpus to guaranntee there is no user
1867 stop_machine_run(__build_all_zonelists, NULL, NR_CPUS);
1868 /* cpuset refresh routine should be here */
1870 vm_total_pages = nr_free_pagecache_pages();
1871 printk("Built %i zonelists. Total pages: %ld\n",
1872 num_online_nodes(), vm_total_pages);
1876 * Helper functions to size the waitqueue hash table.
1877 * Essentially these want to choose hash table sizes sufficiently
1878 * large so that collisions trying to wait on pages are rare.
1879 * But in fact, the number of active page waitqueues on typical
1880 * systems is ridiculously low, less than 200. So this is even
1881 * conservative, even though it seems large.
1883 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
1884 * waitqueues, i.e. the size of the waitq table given the number of pages.
1886 #define PAGES_PER_WAITQUEUE 256
1888 #ifndef CONFIG_MEMORY_HOTPLUG
1889 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
1891 unsigned long size = 1;
1893 pages /= PAGES_PER_WAITQUEUE;
1895 while (size < pages)
1899 * Once we have dozens or even hundreds of threads sleeping
1900 * on IO we've got bigger problems than wait queue collision.
1901 * Limit the size of the wait table to a reasonable size.
1903 size = min(size, 4096UL);
1905 return max(size, 4UL);
1909 * A zone's size might be changed by hot-add, so it is not possible to determine
1910 * a suitable size for its wait_table. So we use the maximum size now.
1912 * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie:
1914 * i386 (preemption config) : 4096 x 16 = 64Kbyte.
1915 * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
1916 * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte.
1918 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
1919 * or more by the traditional way. (See above). It equals:
1921 * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte.
1922 * ia64(16K page size) : = ( 8G + 4M)byte.
1923 * powerpc (64K page size) : = (32G +16M)byte.
1925 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
1932 * This is an integer logarithm so that shifts can be used later
1933 * to extract the more random high bits from the multiplicative
1934 * hash function before the remainder is taken.
1936 static inline unsigned long wait_table_bits(unsigned long size)
1941 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
1944 * Initially all pages are reserved - free ones are freed
1945 * up by free_all_bootmem() once the early boot process is
1946 * done. Non-atomic initialization, single-pass.
1948 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
1949 unsigned long start_pfn, enum memmap_context context)
1952 unsigned long end_pfn = start_pfn + size;
1955 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1957 * There can be holes in boot-time mem_map[]s
1958 * handed to this function. They do not
1959 * exist on hotplugged memory.
1961 if (context == MEMMAP_EARLY) {
1962 if (!early_pfn_valid(pfn))
1964 if (!early_pfn_in_nid(pfn, nid))
1967 page = pfn_to_page(pfn);
1968 set_page_links(page, zone, nid, pfn);
1969 init_page_count(page);
1970 reset_page_mapcount(page);
1971 SetPageReserved(page);
1972 INIT_LIST_HEAD(&page->lru);
1973 #ifdef WANT_PAGE_VIRTUAL
1974 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
1975 if (!is_highmem_idx(zone))
1976 set_page_address(page, __va(pfn << PAGE_SHIFT));
1981 void zone_init_free_lists(struct pglist_data *pgdat, struct zone *zone,
1985 for (order = 0; order < MAX_ORDER ; order++) {
1986 INIT_LIST_HEAD(&zone->free_area[order].free_list);
1987 zone->free_area[order].nr_free = 0;
1991 #ifndef __HAVE_ARCH_MEMMAP_INIT
1992 #define memmap_init(size, nid, zone, start_pfn) \
1993 memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
1996 static int __cpuinit zone_batchsize(struct zone *zone)
2001 * The per-cpu-pages pools are set to around 1000th of the
2002 * size of the zone. But no more than 1/2 of a meg.
2004 * OK, so we don't know how big the cache is. So guess.
2006 batch = zone->present_pages / 1024;
2007 if (batch * PAGE_SIZE > 512 * 1024)
2008 batch = (512 * 1024) / PAGE_SIZE;
2009 batch /= 4; /* We effectively *= 4 below */
2014 * Clamp the batch to a 2^n - 1 value. Having a power
2015 * of 2 value was found to be more likely to have
2016 * suboptimal cache aliasing properties in some cases.
2018 * For example if 2 tasks are alternately allocating
2019 * batches of pages, one task can end up with a lot
2020 * of pages of one half of the possible page colors
2021 * and the other with pages of the other colors.
2023 batch = (1 << (fls(batch + batch/2)-1)) - 1;
2028 inline void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
2030 struct per_cpu_pages *pcp;
2032 memset(p, 0, sizeof(*p));
2034 pcp = &p->pcp[0]; /* hot */
2036 pcp->high = 6 * batch;
2037 pcp->batch = max(1UL, 1 * batch);
2038 INIT_LIST_HEAD(&pcp->list);
2040 pcp = &p->pcp[1]; /* cold*/
2042 pcp->high = 2 * batch;
2043 pcp->batch = max(1UL, batch/2);
2044 INIT_LIST_HEAD(&pcp->list);
2048 * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
2049 * to the value high for the pageset p.
2052 static void setup_pagelist_highmark(struct per_cpu_pageset *p,
2055 struct per_cpu_pages *pcp;
2057 pcp = &p->pcp[0]; /* hot list */
2059 pcp->batch = max(1UL, high/4);
2060 if ((high/4) > (PAGE_SHIFT * 8))
2061 pcp->batch = PAGE_SHIFT * 8;
2067 * Boot pageset table. One per cpu which is going to be used for all
2068 * zones and all nodes. The parameters will be set in such a way
2069 * that an item put on a list will immediately be handed over to
2070 * the buddy list. This is safe since pageset manipulation is done
2071 * with interrupts disabled.
2073 * Some NUMA counter updates may also be caught by the boot pagesets.
2075 * The boot_pagesets must be kept even after bootup is complete for
2076 * unused processors and/or zones. They do play a role for bootstrapping
2077 * hotplugged processors.
2079 * zoneinfo_show() and maybe other functions do
2080 * not check if the processor is online before following the pageset pointer.
2081 * Other parts of the kernel may not check if the zone is available.
2083 static struct per_cpu_pageset boot_pageset[NR_CPUS];
2086 * Dynamically allocate memory for the
2087 * per cpu pageset array in struct zone.
2089 static int __cpuinit process_zones(int cpu)
2091 struct zone *zone, *dzone;
2093 for_each_zone(zone) {
2095 if (!populated_zone(zone))
2098 zone_pcp(zone, cpu) = kmalloc_node(sizeof(struct per_cpu_pageset),
2099 GFP_KERNEL, cpu_to_node(cpu));
2100 if (!zone_pcp(zone, cpu))
2103 setup_pageset(zone_pcp(zone, cpu), zone_batchsize(zone));
2105 if (percpu_pagelist_fraction)
2106 setup_pagelist_highmark(zone_pcp(zone, cpu),
2107 (zone->present_pages / percpu_pagelist_fraction));
2112 for_each_zone(dzone) {
2115 kfree(zone_pcp(dzone, cpu));
2116 zone_pcp(dzone, cpu) = NULL;
2121 static inline void free_zone_pagesets(int cpu)
2125 for_each_zone(zone) {
2126 struct per_cpu_pageset *pset = zone_pcp(zone, cpu);
2128 /* Free per_cpu_pageset if it is slab allocated */
2129 if (pset != &boot_pageset[cpu])
2131 zone_pcp(zone, cpu) = NULL;
2135 static int __cpuinit pageset_cpuup_callback(struct notifier_block *nfb,
2136 unsigned long action,
2139 int cpu = (long)hcpu;
2140 int ret = NOTIFY_OK;
2143 case CPU_UP_PREPARE:
2144 if (process_zones(cpu))
2147 case CPU_UP_CANCELED:
2149 free_zone_pagesets(cpu);
2157 static struct notifier_block __cpuinitdata pageset_notifier =
2158 { &pageset_cpuup_callback, NULL, 0 };
2160 void __init setup_per_cpu_pageset(void)
2164 /* Initialize per_cpu_pageset for cpu 0.
2165 * A cpuup callback will do this for every cpu
2166 * as it comes online
2168 err = process_zones(smp_processor_id());
2170 register_cpu_notifier(&pageset_notifier);
2176 int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
2179 struct pglist_data *pgdat = zone->zone_pgdat;
2183 * The per-page waitqueue mechanism uses hashed waitqueues
2186 zone->wait_table_hash_nr_entries =
2187 wait_table_hash_nr_entries(zone_size_pages);
2188 zone->wait_table_bits =
2189 wait_table_bits(zone->wait_table_hash_nr_entries);
2190 alloc_size = zone->wait_table_hash_nr_entries
2191 * sizeof(wait_queue_head_t);
2193 if (system_state == SYSTEM_BOOTING) {
2194 zone->wait_table = (wait_queue_head_t *)
2195 alloc_bootmem_node(pgdat, alloc_size);
2198 * This case means that a zone whose size was 0 gets new memory
2199 * via memory hot-add.
2200 * But it may be the case that a new node was hot-added. In
2201 * this case vmalloc() will not be able to use this new node's
2202 * memory - this wait_table must be initialized to use this new
2203 * node itself as well.
2204 * To use this new node's memory, further consideration will be
2207 zone->wait_table = (wait_queue_head_t *)vmalloc(alloc_size);
2209 if (!zone->wait_table)
2212 for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
2213 init_waitqueue_head(zone->wait_table + i);
2218 static __meminit void zone_pcp_init(struct zone *zone)
2221 unsigned long batch = zone_batchsize(zone);
2223 for (cpu = 0; cpu < NR_CPUS; cpu++) {
2225 /* Early boot. Slab allocator not functional yet */
2226 zone_pcp(zone, cpu) = &boot_pageset[cpu];
2227 setup_pageset(&boot_pageset[cpu],0);
2229 setup_pageset(zone_pcp(zone,cpu), batch);
2232 if (zone->present_pages)
2233 printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%lu\n",
2234 zone->name, zone->present_pages, batch);
2237 __meminit int init_currently_empty_zone(struct zone *zone,
2238 unsigned long zone_start_pfn,
2240 enum memmap_context context)
2242 struct pglist_data *pgdat = zone->zone_pgdat;
2244 ret = zone_wait_table_init(zone, size);
2247 pgdat->nr_zones = zone_idx(zone) + 1;
2249 zone->zone_start_pfn = zone_start_pfn;
2251 memmap_init(size, pgdat->node_id, zone_idx(zone), zone_start_pfn);
2253 zone_init_free_lists(pgdat, zone, zone->spanned_pages);
2258 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
2260 * Basic iterator support. Return the first range of PFNs for a node
2261 * Note: nid == MAX_NUMNODES returns first region regardless of node
2263 static int __init first_active_region_index_in_nid(int nid)
2267 for (i = 0; i < nr_nodemap_entries; i++)
2268 if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
2275 * Basic iterator support. Return the next active range of PFNs for a node
2276 * Note: nid == MAX_NUMNODES returns next region regardles of node
2278 static int __init next_active_region_index_in_nid(int index, int nid)
2280 for (index = index + 1; index < nr_nodemap_entries; index++)
2281 if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
2287 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
2289 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
2290 * Architectures may implement their own version but if add_active_range()
2291 * was used and there are no special requirements, this is a convenient
2294 int __init early_pfn_to_nid(unsigned long pfn)
2298 for (i = 0; i < nr_nodemap_entries; i++) {
2299 unsigned long start_pfn = early_node_map[i].start_pfn;
2300 unsigned long end_pfn = early_node_map[i].end_pfn;
2302 if (start_pfn <= pfn && pfn < end_pfn)
2303 return early_node_map[i].nid;
2308 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
2310 /* Basic iterator support to walk early_node_map[] */
2311 #define for_each_active_range_index_in_nid(i, nid) \
2312 for (i = first_active_region_index_in_nid(nid); i != -1; \
2313 i = next_active_region_index_in_nid(i, nid))
2316 * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
2317 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
2318 * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
2320 * If an architecture guarantees that all ranges registered with
2321 * add_active_ranges() contain no holes and may be freed, this
2322 * this function may be used instead of calling free_bootmem() manually.
2324 void __init free_bootmem_with_active_regions(int nid,
2325 unsigned long max_low_pfn)
2329 for_each_active_range_index_in_nid(i, nid) {
2330 unsigned long size_pages = 0;
2331 unsigned long end_pfn = early_node_map[i].end_pfn;
2333 if (early_node_map[i].start_pfn >= max_low_pfn)
2336 if (end_pfn > max_low_pfn)
2337 end_pfn = max_low_pfn;
2339 size_pages = end_pfn - early_node_map[i].start_pfn;
2340 free_bootmem_node(NODE_DATA(early_node_map[i].nid),
2341 PFN_PHYS(early_node_map[i].start_pfn),
2342 size_pages << PAGE_SHIFT);
2347 * sparse_memory_present_with_active_regions - Call memory_present for each active range
2348 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
2350 * If an architecture guarantees that all ranges registered with
2351 * add_active_ranges() contain no holes and may be freed, this
2352 * function may be used instead of calling memory_present() manually.
2354 void __init sparse_memory_present_with_active_regions(int nid)
2358 for_each_active_range_index_in_nid(i, nid)
2359 memory_present(early_node_map[i].nid,
2360 early_node_map[i].start_pfn,
2361 early_node_map[i].end_pfn);
2365 * push_node_boundaries - Push node boundaries to at least the requested boundary
2366 * @nid: The nid of the node to push the boundary for
2367 * @start_pfn: The start pfn of the node
2368 * @end_pfn: The end pfn of the node
2370 * In reserve-based hot-add, mem_map is allocated that is unused until hotadd
2371 * time. Specifically, on x86_64, SRAT will report ranges that can potentially
2372 * be hotplugged even though no physical memory exists. This function allows
2373 * an arch to push out the node boundaries so mem_map is allocated that can
2376 #ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
2377 void __init push_node_boundaries(unsigned int nid,
2378 unsigned long start_pfn, unsigned long end_pfn)
2380 printk(KERN_DEBUG "Entering push_node_boundaries(%u, %lu, %lu)\n",
2381 nid, start_pfn, end_pfn);
2383 /* Initialise the boundary for this node if necessary */
2384 if (node_boundary_end_pfn[nid] == 0)
2385 node_boundary_start_pfn[nid] = -1UL;
2387 /* Update the boundaries */
2388 if (node_boundary_start_pfn[nid] > start_pfn)
2389 node_boundary_start_pfn[nid] = start_pfn;
2390 if (node_boundary_end_pfn[nid] < end_pfn)
2391 node_boundary_end_pfn[nid] = end_pfn;
2394 /* If necessary, push the node boundary out for reserve hotadd */
2395 static void __init account_node_boundary(unsigned int nid,
2396 unsigned long *start_pfn, unsigned long *end_pfn)
2398 printk(KERN_DEBUG "Entering account_node_boundary(%u, %lu, %lu)\n",
2399 nid, *start_pfn, *end_pfn);
2401 /* Return if boundary information has not been provided */
2402 if (node_boundary_end_pfn[nid] == 0)
2405 /* Check the boundaries and update if necessary */
2406 if (node_boundary_start_pfn[nid] < *start_pfn)
2407 *start_pfn = node_boundary_start_pfn[nid];
2408 if (node_boundary_end_pfn[nid] > *end_pfn)
2409 *end_pfn = node_boundary_end_pfn[nid];
2412 void __init push_node_boundaries(unsigned int nid,
2413 unsigned long start_pfn, unsigned long end_pfn) {}
2415 static void __init account_node_boundary(unsigned int nid,
2416 unsigned long *start_pfn, unsigned long *end_pfn) {}
2421 * get_pfn_range_for_nid - Return the start and end page frames for a node
2422 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
2423 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
2424 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
2426 * It returns the start and end page frame of a node based on information
2427 * provided by an arch calling add_active_range(). If called for a node
2428 * with no available memory, a warning is printed and the start and end
2431 void __init get_pfn_range_for_nid(unsigned int nid,
2432 unsigned long *start_pfn, unsigned long *end_pfn)
2438 for_each_active_range_index_in_nid(i, nid) {
2439 *start_pfn = min(*start_pfn, early_node_map[i].start_pfn);
2440 *end_pfn = max(*end_pfn, early_node_map[i].end_pfn);
2443 if (*start_pfn == -1UL) {
2444 printk(KERN_WARNING "Node %u active with no memory\n", nid);
2448 /* Push the node boundaries out if requested */
2449 account_node_boundary(nid, start_pfn, end_pfn);
2453 * Return the number of pages a zone spans in a node, including holes
2454 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
2456 unsigned long __init zone_spanned_pages_in_node(int nid,
2457 unsigned long zone_type,
2458 unsigned long *ignored)
2460 unsigned long node_start_pfn, node_end_pfn;
2461 unsigned long zone_start_pfn, zone_end_pfn;
2463 /* Get the start and end of the node and zone */
2464 get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
2465 zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
2466 zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
2468 /* Check that this node has pages within the zone's required range */
2469 if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
2472 /* Move the zone boundaries inside the node if necessary */
2473 zone_end_pfn = min(zone_end_pfn, node_end_pfn);
2474 zone_start_pfn = max(zone_start_pfn, node_start_pfn);
2476 /* Return the spanned pages */
2477 return zone_end_pfn - zone_start_pfn;
2481 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
2482 * then all holes in the requested range will be accounted for.
2484 unsigned long __init __absent_pages_in_range(int nid,
2485 unsigned long range_start_pfn,
2486 unsigned long range_end_pfn)
2489 unsigned long prev_end_pfn = 0, hole_pages = 0;
2490 unsigned long start_pfn;
2492 /* Find the end_pfn of the first active range of pfns in the node */
2493 i = first_active_region_index_in_nid(nid);
2497 /* Account for ranges before physical memory on this node */
2498 if (early_node_map[i].start_pfn > range_start_pfn)
2499 hole_pages = early_node_map[i].start_pfn - range_start_pfn;
2501 prev_end_pfn = early_node_map[i].start_pfn;
2503 /* Find all holes for the zone within the node */
2504 for (; i != -1; i = next_active_region_index_in_nid(i, nid)) {
2506 /* No need to continue if prev_end_pfn is outside the zone */
2507 if (prev_end_pfn >= range_end_pfn)
2510 /* Make sure the end of the zone is not within the hole */
2511 start_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
2512 prev_end_pfn = max(prev_end_pfn, range_start_pfn);
2514 /* Update the hole size cound and move on */
2515 if (start_pfn > range_start_pfn) {
2516 BUG_ON(prev_end_pfn > start_pfn);
2517 hole_pages += start_pfn - prev_end_pfn;
2519 prev_end_pfn = early_node_map[i].end_pfn;
2522 /* Account for ranges past physical memory on this node */
2523 if (range_end_pfn > prev_end_pfn)
2524 hole_pages += range_end_pfn -
2525 max(range_start_pfn, prev_end_pfn);
2531 * absent_pages_in_range - Return number of page frames in holes within a range
2532 * @start_pfn: The start PFN to start searching for holes
2533 * @end_pfn: The end PFN to stop searching for holes
2535 * It returns the number of pages frames in memory holes within a range.
2537 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
2538 unsigned long end_pfn)
2540 return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
2543 /* Return the number of page frames in holes in a zone on a node */
2544 unsigned long __init zone_absent_pages_in_node(int nid,
2545 unsigned long zone_type,
2546 unsigned long *ignored)
2548 unsigned long node_start_pfn, node_end_pfn;
2549 unsigned long zone_start_pfn, zone_end_pfn;
2551 get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
2552 zone_start_pfn = max(arch_zone_lowest_possible_pfn[zone_type],
2554 zone_end_pfn = min(arch_zone_highest_possible_pfn[zone_type],
2557 return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
2561 static inline unsigned long zone_spanned_pages_in_node(int nid,
2562 unsigned long zone_type,
2563 unsigned long *zones_size)
2565 return zones_size[zone_type];
2568 static inline unsigned long zone_absent_pages_in_node(int nid,
2569 unsigned long zone_type,
2570 unsigned long *zholes_size)
2575 return zholes_size[zone_type];
2580 static void __init calculate_node_totalpages(struct pglist_data *pgdat,
2581 unsigned long *zones_size, unsigned long *zholes_size)
2583 unsigned long realtotalpages, totalpages = 0;
2586 for (i = 0; i < MAX_NR_ZONES; i++)
2587 totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
2589 pgdat->node_spanned_pages = totalpages;
2591 realtotalpages = totalpages;
2592 for (i = 0; i < MAX_NR_ZONES; i++)
2594 zone_absent_pages_in_node(pgdat->node_id, i,
2596 pgdat->node_present_pages = realtotalpages;
2597 printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
2602 * Set up the zone data structures:
2603 * - mark all pages reserved
2604 * - mark all memory queues empty
2605 * - clear the memory bitmaps
2607 static void __meminit free_area_init_core(struct pglist_data *pgdat,
2608 unsigned long *zones_size, unsigned long *zholes_size)
2611 int nid = pgdat->node_id;
2612 unsigned long zone_start_pfn = pgdat->node_start_pfn;
2615 pgdat_resize_init(pgdat);
2616 pgdat->nr_zones = 0;
2617 init_waitqueue_head(&pgdat->kswapd_wait);
2618 pgdat->kswapd_max_order = 0;
2620 for (j = 0; j < MAX_NR_ZONES; j++) {
2621 struct zone *zone = pgdat->node_zones + j;
2622 unsigned long size, realsize, memmap_pages;
2624 size = zone_spanned_pages_in_node(nid, j, zones_size);
2625 realsize = size - zone_absent_pages_in_node(nid, j,
2629 * Adjust realsize so that it accounts for how much memory
2630 * is used by this zone for memmap. This affects the watermark
2631 * and per-cpu initialisations
2633 memmap_pages = (size * sizeof(struct page)) >> PAGE_SHIFT;
2634 if (realsize >= memmap_pages) {
2635 realsize -= memmap_pages;
2637 " %s zone: %lu pages used for memmap\n",
2638 zone_names[j], memmap_pages);
2641 " %s zone: %lu pages exceeds realsize %lu\n",
2642 zone_names[j], memmap_pages, realsize);
2644 /* Account for reserved DMA pages */
2645 if (j == ZONE_DMA && realsize > dma_reserve) {
2646 realsize -= dma_reserve;
2647 printk(KERN_DEBUG " DMA zone: %lu pages reserved\n",
2651 if (!is_highmem_idx(j))
2652 nr_kernel_pages += realsize;
2653 nr_all_pages += realsize;
2655 zone->spanned_pages = size;
2656 zone->present_pages = realsize;
2659 zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
2661 zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
2663 zone->name = zone_names[j];
2664 spin_lock_init(&zone->lock);
2665 spin_lock_init(&zone->lru_lock);
2666 zone_seqlock_init(zone);
2667 zone->zone_pgdat = pgdat;
2669 zone->prev_priority = DEF_PRIORITY;
2671 zone_pcp_init(zone);
2672 INIT_LIST_HEAD(&zone->active_list);
2673 INIT_LIST_HEAD(&zone->inactive_list);
2674 zone->nr_scan_active = 0;
2675 zone->nr_scan_inactive = 0;
2676 zap_zone_vm_stats(zone);
2677 atomic_set(&zone->reclaim_in_progress, 0);
2681 ret = init_currently_empty_zone(zone, zone_start_pfn,
2682 size, MEMMAP_EARLY);
2684 zone_start_pfn += size;
2688 static void __init alloc_node_mem_map(struct pglist_data *pgdat)
2690 /* Skip empty nodes */
2691 if (!pgdat->node_spanned_pages)
2694 #ifdef CONFIG_FLAT_NODE_MEM_MAP
2695 /* ia64 gets its own node_mem_map, before this, without bootmem */
2696 if (!pgdat->node_mem_map) {
2697 unsigned long size, start, end;
2701 * The zone's endpoints aren't required to be MAX_ORDER
2702 * aligned but the node_mem_map endpoints must be in order
2703 * for the buddy allocator to function correctly.
2705 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
2706 end = pgdat->node_start_pfn + pgdat->node_spanned_pages;
2707 end = ALIGN(end, MAX_ORDER_NR_PAGES);
2708 size = (end - start) * sizeof(struct page);
2709 map = alloc_remap(pgdat->node_id, size);
2711 map = alloc_bootmem_node(pgdat, size);
2712 pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
2714 #ifdef CONFIG_FLATMEM
2716 * With no DISCONTIG, the global mem_map is just set as node 0's
2718 if (pgdat == NODE_DATA(0)) {
2719 mem_map = NODE_DATA(0)->node_mem_map;
2720 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
2721 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
2722 mem_map -= pgdat->node_start_pfn;
2723 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
2726 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
2729 void __meminit free_area_init_node(int nid, struct pglist_data *pgdat,
2730 unsigned long *zones_size, unsigned long node_start_pfn,
2731 unsigned long *zholes_size)
2733 pgdat->node_id = nid;
2734 pgdat->node_start_pfn = node_start_pfn;
2735 calculate_node_totalpages(pgdat, zones_size, zholes_size);
2737 alloc_node_mem_map(pgdat);
2739 free_area_init_core(pgdat, zones_size, zholes_size);
2742 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
2744 * add_active_range - Register a range of PFNs backed by physical memory
2745 * @nid: The node ID the range resides on
2746 * @start_pfn: The start PFN of the available physical memory
2747 * @end_pfn: The end PFN of the available physical memory
2749 * These ranges are stored in an early_node_map[] and later used by
2750 * free_area_init_nodes() to calculate zone sizes and holes. If the
2751 * range spans a memory hole, it is up to the architecture to ensure
2752 * the memory is not freed by the bootmem allocator. If possible
2753 * the range being registered will be merged with existing ranges.
2755 void __init add_active_range(unsigned int nid, unsigned long start_pfn,
2756 unsigned long end_pfn)
2760 printk(KERN_DEBUG "Entering add_active_range(%d, %lu, %lu) "
2761 "%d entries of %d used\n",
2762 nid, start_pfn, end_pfn,
2763 nr_nodemap_entries, MAX_ACTIVE_REGIONS);
2765 /* Merge with existing active regions if possible */
2766 for (i = 0; i < nr_nodemap_entries; i++) {
2767 if (early_node_map[i].nid != nid)
2770 /* Skip if an existing region covers this new one */
2771 if (start_pfn >= early_node_map[i].start_pfn &&
2772 end_pfn <= early_node_map[i].end_pfn)
2775 /* Merge forward if suitable */
2776 if (start_pfn <= early_node_map[i].end_pfn &&
2777 end_pfn > early_node_map[i].end_pfn) {
2778 early_node_map[i].end_pfn = end_pfn;
2782 /* Merge backward if suitable */
2783 if (start_pfn < early_node_map[i].end_pfn &&
2784 end_pfn >= early_node_map[i].start_pfn) {
2785 early_node_map[i].start_pfn = start_pfn;
2790 /* Check that early_node_map is large enough */
2791 if (i >= MAX_ACTIVE_REGIONS) {
2792 printk(KERN_CRIT "More than %d memory regions, truncating\n",
2793 MAX_ACTIVE_REGIONS);
2797 early_node_map[i].nid = nid;
2798 early_node_map[i].start_pfn = start_pfn;
2799 early_node_map[i].end_pfn = end_pfn;
2800 nr_nodemap_entries = i + 1;
2804 * shrink_active_range - Shrink an existing registered range of PFNs
2805 * @nid: The node id the range is on that should be shrunk
2806 * @old_end_pfn: The old end PFN of the range
2807 * @new_end_pfn: The new PFN of the range
2809 * i386 with NUMA use alloc_remap() to store a node_mem_map on a local node.
2810 * The map is kept at the end physical page range that has already been
2811 * registered with add_active_range(). This function allows an arch to shrink
2812 * an existing registered range.
2814 void __init shrink_active_range(unsigned int nid, unsigned long old_end_pfn,
2815 unsigned long new_end_pfn)
2819 /* Find the old active region end and shrink */
2820 for_each_active_range_index_in_nid(i, nid)
2821 if (early_node_map[i].end_pfn == old_end_pfn) {
2822 early_node_map[i].end_pfn = new_end_pfn;
2828 * remove_all_active_ranges - Remove all currently registered regions
2830 * During discovery, it may be found that a table like SRAT is invalid
2831 * and an alternative discovery method must be used. This function removes
2832 * all currently registered regions.
2834 void __init remove_all_active_ranges(void)
2836 memset(early_node_map, 0, sizeof(early_node_map));
2837 nr_nodemap_entries = 0;
2838 #ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
2839 memset(node_boundary_start_pfn, 0, sizeof(node_boundary_start_pfn));
2840 memset(node_boundary_end_pfn, 0, sizeof(node_boundary_end_pfn));
2841 #endif /* CONFIG_MEMORY_HOTPLUG_RESERVE */
2844 /* Compare two active node_active_regions */
2845 static int __init cmp_node_active_region(const void *a, const void *b)
2847 struct node_active_region *arange = (struct node_active_region *)a;
2848 struct node_active_region *brange = (struct node_active_region *)b;
2850 /* Done this way to avoid overflows */
2851 if (arange->start_pfn > brange->start_pfn)
2853 if (arange->start_pfn < brange->start_pfn)
2859 /* sort the node_map by start_pfn */
2860 static void __init sort_node_map(void)
2862 sort(early_node_map, (size_t)nr_nodemap_entries,
2863 sizeof(struct node_active_region),
2864 cmp_node_active_region, NULL);
2867 /* Find the lowest pfn for a node */
2868 unsigned long __init find_min_pfn_for_node(unsigned long nid)
2871 unsigned long min_pfn = ULONG_MAX;
2873 /* Assuming a sorted map, the first range found has the starting pfn */
2874 for_each_active_range_index_in_nid(i, nid)
2875 min_pfn = min(min_pfn, early_node_map[i].start_pfn);
2877 if (min_pfn == ULONG_MAX) {
2879 "Could not find start_pfn for node %lu\n", nid);
2887 * find_min_pfn_with_active_regions - Find the minimum PFN registered
2889 * It returns the minimum PFN based on information provided via
2890 * add_active_range().
2892 unsigned long __init find_min_pfn_with_active_regions(void)
2894 return find_min_pfn_for_node(MAX_NUMNODES);
2898 * find_max_pfn_with_active_regions - Find the maximum PFN registered
2900 * It returns the maximum PFN based on information provided via
2901 * add_active_range().
2903 unsigned long __init find_max_pfn_with_active_regions(void)
2906 unsigned long max_pfn = 0;
2908 for (i = 0; i < nr_nodemap_entries; i++)
2909 max_pfn = max(max_pfn, early_node_map[i].end_pfn);
2915 * free_area_init_nodes - Initialise all pg_data_t and zone data
2916 * @max_zone_pfn: an array of max PFNs for each zone
2918 * This will call free_area_init_node() for each active node in the system.
2919 * Using the page ranges provided by add_active_range(), the size of each
2920 * zone in each node and their holes is calculated. If the maximum PFN
2921 * between two adjacent zones match, it is assumed that the zone is empty.
2922 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
2923 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
2924 * starts where the previous one ended. For example, ZONE_DMA32 starts
2925 * at arch_max_dma_pfn.
2927 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
2932 /* Sort early_node_map as initialisation assumes it is sorted */
2935 /* Record where the zone boundaries are */
2936 memset(arch_zone_lowest_possible_pfn, 0,
2937 sizeof(arch_zone_lowest_possible_pfn));
2938 memset(arch_zone_highest_possible_pfn, 0,
2939 sizeof(arch_zone_highest_possible_pfn));
2940 arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
2941 arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
2942 for (i = 1; i < MAX_NR_ZONES; i++) {
2943 arch_zone_lowest_possible_pfn[i] =
2944 arch_zone_highest_possible_pfn[i-1];
2945 arch_zone_highest_possible_pfn[i] =
2946 max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
2949 /* Print out the zone ranges */
2950 printk("Zone PFN ranges:\n");
2951 for (i = 0; i < MAX_NR_ZONES; i++)
2952 printk(" %-8s %8lu -> %8lu\n",
2954 arch_zone_lowest_possible_pfn[i],
2955 arch_zone_highest_possible_pfn[i]);
2957 /* Print out the early_node_map[] */
2958 printk("early_node_map[%d] active PFN ranges\n", nr_nodemap_entries);
2959 for (i = 0; i < nr_nodemap_entries; i++)
2960 printk(" %3d: %8lu -> %8lu\n", early_node_map[i].nid,
2961 early_node_map[i].start_pfn,
2962 early_node_map[i].end_pfn);
2964 /* Initialise every node */
2965 for_each_online_node(nid) {
2966 pg_data_t *pgdat = NODE_DATA(nid);
2967 free_area_init_node(nid, pgdat, NULL,
2968 find_min_pfn_for_node(nid), NULL);
2971 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
2974 * set_dma_reserve - set the specified number of pages reserved in the first zone
2975 * @new_dma_reserve: The number of pages to mark reserved
2977 * The per-cpu batchsize and zone watermarks are determined by present_pages.
2978 * In the DMA zone, a significant percentage may be consumed by kernel image
2979 * and other unfreeable allocations which can skew the watermarks badly. This
2980 * function may optionally be used to account for unfreeable pages in the
2981 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
2982 * smaller per-cpu batchsize.
2984 void __init set_dma_reserve(unsigned long new_dma_reserve)
2986 dma_reserve = new_dma_reserve;
2989 #ifndef CONFIG_NEED_MULTIPLE_NODES
2990 static bootmem_data_t contig_bootmem_data;
2991 struct pglist_data contig_page_data = { .bdata = &contig_bootmem_data };
2993 EXPORT_SYMBOL(contig_page_data);
2996 void __init free_area_init(unsigned long *zones_size)
2998 free_area_init_node(0, NODE_DATA(0), zones_size,
2999 __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
3002 static int page_alloc_cpu_notify(struct notifier_block *self,
3003 unsigned long action, void *hcpu)
3005 int cpu = (unsigned long)hcpu;
3007 if (action == CPU_DEAD) {
3008 local_irq_disable();
3010 vm_events_fold_cpu(cpu);
3012 refresh_cpu_vm_stats(cpu);
3017 void __init page_alloc_init(void)
3019 hotcpu_notifier(page_alloc_cpu_notify, 0);
3023 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
3024 * or min_free_kbytes changes.
3026 static void calculate_totalreserve_pages(void)
3028 struct pglist_data *pgdat;
3029 unsigned long reserve_pages = 0;
3030 enum zone_type i, j;
3032 for_each_online_pgdat(pgdat) {
3033 for (i = 0; i < MAX_NR_ZONES; i++) {
3034 struct zone *zone = pgdat->node_zones + i;
3035 unsigned long max = 0;
3037 /* Find valid and maximum lowmem_reserve in the zone */
3038 for (j = i; j < MAX_NR_ZONES; j++) {
3039 if (zone->lowmem_reserve[j] > max)
3040 max = zone->lowmem_reserve[j];
3043 /* we treat pages_high as reserved pages. */
3044 max += zone->pages_high;
3046 if (max > zone->present_pages)
3047 max = zone->present_pages;
3048 reserve_pages += max;
3051 totalreserve_pages = reserve_pages;
3055 * setup_per_zone_lowmem_reserve - called whenever
3056 * sysctl_lower_zone_reserve_ratio changes. Ensures that each zone
3057 * has a correct pages reserved value, so an adequate number of
3058 * pages are left in the zone after a successful __alloc_pages().
3060 static void setup_per_zone_lowmem_reserve(void)
3062 struct pglist_data *pgdat;
3063 enum zone_type j, idx;
3065 for_each_online_pgdat(pgdat) {
3066 for (j = 0; j < MAX_NR_ZONES; j++) {
3067 struct zone *zone = pgdat->node_zones + j;
3068 unsigned long present_pages = zone->present_pages;
3070 zone->lowmem_reserve[j] = 0;
3074 struct zone *lower_zone;
3078 if (sysctl_lowmem_reserve_ratio[idx] < 1)
3079 sysctl_lowmem_reserve_ratio[idx] = 1;
3081 lower_zone = pgdat->node_zones + idx;
3082 lower_zone->lowmem_reserve[j] = present_pages /
3083 sysctl_lowmem_reserve_ratio[idx];
3084 present_pages += lower_zone->present_pages;
3089 /* update totalreserve_pages */
3090 calculate_totalreserve_pages();
3094 * setup_per_zone_pages_min - called when min_free_kbytes changes.
3096 * Ensures that the pages_{min,low,high} values for each zone are set correctly
3097 * with respect to min_free_kbytes.
3099 void setup_per_zone_pages_min(void)
3101 unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
3102 unsigned long lowmem_pages = 0;
3104 unsigned long flags;
3106 /* Calculate total number of !ZONE_HIGHMEM pages */
3107 for_each_zone(zone) {
3108 if (!is_highmem(zone))
3109 lowmem_pages += zone->present_pages;
3112 for_each_zone(zone) {
3115 spin_lock_irqsave(&zone->lru_lock, flags);
3116 tmp = (u64)pages_min * zone->present_pages;
3117 do_div(tmp, lowmem_pages);
3118 if (is_highmem(zone)) {
3120 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
3121 * need highmem pages, so cap pages_min to a small
3124 * The (pages_high-pages_low) and (pages_low-pages_min)
3125 * deltas controls asynch page reclaim, and so should
3126 * not be capped for highmem.
3130 min_pages = zone->present_pages / 1024;
3131 if (min_pages < SWAP_CLUSTER_MAX)
3132 min_pages = SWAP_CLUSTER_MAX;
3133 if (min_pages > 128)
3135 zone->pages_min = min_pages;
3138 * If it's a lowmem zone, reserve a number of pages
3139 * proportionate to the zone's size.
3141 zone->pages_min = tmp;
3144 zone->pages_low = zone->pages_min + (tmp >> 2);
3145 zone->pages_high = zone->pages_min + (tmp >> 1);
3146 spin_unlock_irqrestore(&zone->lru_lock, flags);
3149 /* update totalreserve_pages */
3150 calculate_totalreserve_pages();
3154 * Initialise min_free_kbytes.
3156 * For small machines we want it small (128k min). For large machines
3157 * we want it large (64MB max). But it is not linear, because network
3158 * bandwidth does not increase linearly with machine size. We use
3160 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
3161 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
3177 static int __init init_per_zone_pages_min(void)
3179 unsigned long lowmem_kbytes;
3181 lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
3183 min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
3184 if (min_free_kbytes < 128)
3185 min_free_kbytes = 128;
3186 if (min_free_kbytes > 65536)
3187 min_free_kbytes = 65536;
3188 setup_per_zone_pages_min();
3189 setup_per_zone_lowmem_reserve();
3192 module_init(init_per_zone_pages_min)
3195 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
3196 * that we can call two helper functions whenever min_free_kbytes
3199 int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
3200 struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
3202 proc_dointvec(table, write, file, buffer, length, ppos);
3203 setup_per_zone_pages_min();
3208 int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
3209 struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
3214 rc = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
3219 zone->min_unmapped_pages = (zone->present_pages *
3220 sysctl_min_unmapped_ratio) / 100;
3224 int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
3225 struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
3230 rc = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
3235 zone->min_slab_pages = (zone->present_pages *
3236 sysctl_min_slab_ratio) / 100;
3242 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
3243 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
3244 * whenever sysctl_lowmem_reserve_ratio changes.
3246 * The reserve ratio obviously has absolutely no relation with the
3247 * pages_min watermarks. The lowmem reserve ratio can only make sense
3248 * if in function of the boot time zone sizes.
3250 int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
3251 struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
3253 proc_dointvec_minmax(table, write, file, buffer, length, ppos);
3254 setup_per_zone_lowmem_reserve();
3259 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
3260 * cpu. It is the fraction of total pages in each zone that a hot per cpu pagelist
3261 * can have before it gets flushed back to buddy allocator.
3264 int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
3265 struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
3271 ret = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
3272 if (!write || (ret == -EINVAL))
3274 for_each_zone(zone) {
3275 for_each_online_cpu(cpu) {
3277 high = zone->present_pages / percpu_pagelist_fraction;
3278 setup_pagelist_highmark(zone_pcp(zone, cpu), high);
3284 int hashdist = HASHDIST_DEFAULT;
3287 static int __init set_hashdist(char *str)
3291 hashdist = simple_strtoul(str, &str, 0);
3294 __setup("hashdist=", set_hashdist);
3298 * allocate a large system hash table from bootmem
3299 * - it is assumed that the hash table must contain an exact power-of-2
3300 * quantity of entries
3301 * - limit is the number of hash buckets, not the total allocation size
3303 void *__init alloc_large_system_hash(const char *tablename,
3304 unsigned long bucketsize,
3305 unsigned long numentries,
3308 unsigned int *_hash_shift,
3309 unsigned int *_hash_mask,
3310 unsigned long limit)
3312 unsigned long long max = limit;
3313 unsigned long log2qty, size;
3316 /* allow the kernel cmdline to have a say */
3318 /* round applicable memory size up to nearest megabyte */
3319 numentries = nr_kernel_pages;
3320 numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
3321 numentries >>= 20 - PAGE_SHIFT;
3322 numentries <<= 20 - PAGE_SHIFT;
3324 /* limit to 1 bucket per 2^scale bytes of low memory */
3325 if (scale > PAGE_SHIFT)
3326 numentries >>= (scale - PAGE_SHIFT);
3328 numentries <<= (PAGE_SHIFT - scale);
3330 /* Make sure we've got at least a 0-order allocation.. */
3331 if (unlikely((numentries * bucketsize) < PAGE_SIZE))
3332 numentries = PAGE_SIZE / bucketsize;
3334 numentries = roundup_pow_of_two(numentries);
3336 /* limit allocation size to 1/16 total memory by default */
3338 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
3339 do_div(max, bucketsize);
3342 if (numentries > max)
3345 log2qty = ilog2(numentries);
3348 size = bucketsize << log2qty;
3349 if (flags & HASH_EARLY)
3350 table = alloc_bootmem(size);
3352 table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
3354 unsigned long order;
3355 for (order = 0; ((1UL << order) << PAGE_SHIFT) < size; order++)
3357 table = (void*) __get_free_pages(GFP_ATOMIC, order);
3359 } while (!table && size > PAGE_SIZE && --log2qty);
3362 panic("Failed to allocate %s hash table\n", tablename);
3364 printk("%s hash table entries: %d (order: %d, %lu bytes)\n",
3367 ilog2(size) - PAGE_SHIFT,
3371 *_hash_shift = log2qty;
3373 *_hash_mask = (1 << log2qty) - 1;
3378 #ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
3379 struct page *pfn_to_page(unsigned long pfn)
3381 return __pfn_to_page(pfn);
3383 unsigned long page_to_pfn(struct page *page)
3385 return __page_to_pfn(page);
3387 EXPORT_SYMBOL(pfn_to_page);
3388 EXPORT_SYMBOL(page_to_pfn);
3389 #endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */
3391 #if MAX_NUMNODES > 1
3393 * Find the highest possible node id.
3395 int highest_possible_node_id(void)
3398 unsigned int highest = 0;
3400 for_each_node_mask(node, node_possible_map)
3404 EXPORT_SYMBOL(highest_possible_node_id);