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/config.h>
18 #include <linux/stddef.h>
20 #include <linux/swap.h>
21 #include <linux/interrupt.h>
22 #include <linux/pagemap.h>
23 #include <linux/bootmem.h>
24 #include <linux/compiler.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/suspend.h>
28 #include <linux/pagevec.h>
29 #include <linux/blkdev.h>
30 #include <linux/slab.h>
31 #include <linux/notifier.h>
32 #include <linux/topology.h>
33 #include <linux/sysctl.h>
34 #include <linux/cpu.h>
35 #include <linux/cpuset.h>
36 #include <linux/memory_hotplug.h>
37 #include <linux/nodemask.h>
38 #include <linux/vmalloc.h>
39 #include <linux/mempolicy.h>
41 #include <asm/tlbflush.h>
42 #include <asm/div64.h>
46 * MCD - HACK: Find somewhere to initialize this EARLY, or make this
49 nodemask_t node_online_map __read_mostly = { { [0] = 1UL } };
50 EXPORT_SYMBOL(node_online_map);
51 nodemask_t node_possible_map __read_mostly = NODE_MASK_ALL;
52 EXPORT_SYMBOL(node_possible_map);
53 unsigned long totalram_pages __read_mostly;
54 unsigned long totalhigh_pages __read_mostly;
55 unsigned long totalreserve_pages __read_mostly;
57 int percpu_pagelist_fraction;
59 static void __free_pages_ok(struct page *page, unsigned int order);
62 * results with 256, 32 in the lowmem_reserve sysctl:
63 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
64 * 1G machine -> (16M dma, 784M normal, 224M high)
65 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
66 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
67 * HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
69 * TBD: should special case ZONE_DMA32 machines here - in those we normally
70 * don't need any ZONE_NORMAL reservation
72 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { 256, 256, 32 };
74 EXPORT_SYMBOL(totalram_pages);
77 * Used by page_zone() to look up the address of the struct zone whose
78 * id is encoded in the upper bits of page->flags
80 struct zone *zone_table[1 << ZONETABLE_SHIFT] __read_mostly;
81 EXPORT_SYMBOL(zone_table);
83 static char *zone_names[MAX_NR_ZONES] = { "DMA", "DMA32", "Normal", "HighMem" };
84 int min_free_kbytes = 1024;
86 unsigned long __meminitdata nr_kernel_pages;
87 unsigned long __meminitdata nr_all_pages;
89 #ifdef CONFIG_DEBUG_VM
90 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
94 unsigned long pfn = page_to_pfn(page);
97 seq = zone_span_seqbegin(zone);
98 if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
100 else if (pfn < zone->zone_start_pfn)
102 } while (zone_span_seqretry(zone, seq));
107 static int page_is_consistent(struct zone *zone, struct page *page)
109 #ifdef CONFIG_HOLES_IN_ZONE
110 if (!pfn_valid(page_to_pfn(page)))
113 if (zone != page_zone(page))
119 * Temporary debugging check for pages not lying within a given zone.
121 static int bad_range(struct zone *zone, struct page *page)
123 if (page_outside_zone_boundaries(zone, page))
125 if (!page_is_consistent(zone, page))
132 static inline int bad_range(struct zone *zone, struct page *page)
138 static void bad_page(struct page *page)
140 printk(KERN_EMERG "Bad page state in process '%s'\n"
141 KERN_EMERG "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n"
142 KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
143 KERN_EMERG "Backtrace:\n",
144 current->comm, page, (int)(2*sizeof(unsigned long)),
145 (unsigned long)page->flags, page->mapping,
146 page_mapcount(page), page_count(page));
148 page->flags &= ~(1 << PG_lru |
158 set_page_count(page, 0);
159 reset_page_mapcount(page);
160 page->mapping = NULL;
161 add_taint(TAINT_BAD_PAGE);
165 * Higher-order pages are called "compound pages". They are structured thusly:
167 * The first PAGE_SIZE page is called the "head page".
169 * The remaining PAGE_SIZE pages are called "tail pages".
171 * All pages have PG_compound set. All pages have their ->private pointing at
172 * the head page (even the head page has this).
174 * The first tail page's ->lru.next holds the address of the compound page's
175 * put_page() function. Its ->lru.prev holds the order of allocation.
176 * This usage means that zero-order pages may not be compound.
179 static void free_compound_page(struct page *page)
181 __free_pages_ok(page, (unsigned long)page[1].lru.prev);
184 static void prep_compound_page(struct page *page, unsigned long order)
187 int nr_pages = 1 << order;
189 page[1].lru.next = (void *)free_compound_page; /* set dtor */
190 page[1].lru.prev = (void *)order;
191 for (i = 0; i < nr_pages; i++) {
192 struct page *p = page + i;
194 __SetPageCompound(p);
195 set_page_private(p, (unsigned long)page);
199 static void destroy_compound_page(struct page *page, unsigned long order)
202 int nr_pages = 1 << order;
204 if (unlikely((unsigned long)page[1].lru.prev != order))
207 for (i = 0; i < nr_pages; i++) {
208 struct page *p = page + i;
210 if (unlikely(!PageCompound(p) |
211 (page_private(p) != (unsigned long)page)))
213 __ClearPageCompound(p);
217 static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
221 BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM);
223 * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
224 * and __GFP_HIGHMEM from hard or soft interrupt context.
226 BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
227 for (i = 0; i < (1 << order); i++)
228 clear_highpage(page + i);
232 * function for dealing with page's order in buddy system.
233 * zone->lock is already acquired when we use these.
234 * So, we don't need atomic page->flags operations here.
236 static inline unsigned long page_order(struct page *page)
238 return page_private(page);
241 static inline void set_page_order(struct page *page, int order)
243 set_page_private(page, order);
244 __SetPageBuddy(page);
247 static inline void rmv_page_order(struct page *page)
249 __ClearPageBuddy(page);
250 set_page_private(page, 0);
254 * Locate the struct page for both the matching buddy in our
255 * pair (buddy1) and the combined O(n+1) page they form (page).
257 * 1) Any buddy B1 will have an order O twin B2 which satisfies
258 * the following equation:
260 * For example, if the starting buddy (buddy2) is #8 its order
262 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
264 * 2) Any buddy B will have an order O+1 parent P which
265 * satisfies the following equation:
268 * Assumption: *_mem_map is contigious at least up to MAX_ORDER
270 static inline struct page *
271 __page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
273 unsigned long buddy_idx = page_idx ^ (1 << order);
275 return page + (buddy_idx - page_idx);
278 static inline unsigned long
279 __find_combined_index(unsigned long page_idx, unsigned int order)
281 return (page_idx & ~(1 << order));
285 * This function checks whether a page is free && is the buddy
286 * we can do coalesce a page and its buddy if
287 * (a) the buddy is not in a hole &&
288 * (b) the buddy is in the buddy system &&
289 * (c) a page and its buddy have the same order &&
290 * (d) a page and its buddy are in the same zone.
292 * For recording whether a page is in the buddy system, we use PG_buddy.
293 * Setting, clearing, and testing PG_buddy is serialized by zone->lock.
295 * For recording page's order, we use page_private(page).
297 static inline int page_is_buddy(struct page *page, struct page *buddy,
300 #ifdef CONFIG_HOLES_IN_ZONE
301 if (!pfn_valid(page_to_pfn(buddy)))
305 if (page_zone_id(page) != page_zone_id(buddy))
308 if (PageBuddy(buddy) && page_order(buddy) == order) {
309 BUG_ON(page_count(buddy) != 0);
316 * Freeing function for a buddy system allocator.
318 * The concept of a buddy system is to maintain direct-mapped table
319 * (containing bit values) for memory blocks of various "orders".
320 * The bottom level table contains the map for the smallest allocatable
321 * units of memory (here, pages), and each level above it describes
322 * pairs of units from the levels below, hence, "buddies".
323 * At a high level, all that happens here is marking the table entry
324 * at the bottom level available, and propagating the changes upward
325 * as necessary, plus some accounting needed to play nicely with other
326 * parts of the VM system.
327 * At each level, we keep a list of pages, which are heads of continuous
328 * free pages of length of (1 << order) and marked with PG_buddy. Page's
329 * order is recorded in page_private(page) field.
330 * So when we are allocating or freeing one, we can derive the state of the
331 * other. That is, if we allocate a small block, and both were
332 * free, the remainder of the region must be split into blocks.
333 * If a block is freed, and its buddy is also free, then this
334 * triggers coalescing into a block of larger size.
339 static inline void __free_one_page(struct page *page,
340 struct zone *zone, unsigned int order)
342 unsigned long page_idx;
343 int order_size = 1 << order;
345 if (unlikely(PageCompound(page)))
346 destroy_compound_page(page, order);
348 page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
350 BUG_ON(page_idx & (order_size - 1));
351 BUG_ON(bad_range(zone, page));
353 zone->free_pages += order_size;
354 while (order < MAX_ORDER-1) {
355 unsigned long combined_idx;
356 struct free_area *area;
359 buddy = __page_find_buddy(page, page_idx, order);
360 if (!page_is_buddy(page, buddy, order))
361 break; /* Move the buddy up one level. */
363 list_del(&buddy->lru);
364 area = zone->free_area + order;
366 rmv_page_order(buddy);
367 combined_idx = __find_combined_index(page_idx, order);
368 page = page + (combined_idx - page_idx);
369 page_idx = combined_idx;
372 set_page_order(page, order);
373 list_add(&page->lru, &zone->free_area[order].free_list);
374 zone->free_area[order].nr_free++;
377 static inline int free_pages_check(struct page *page)
379 if (unlikely(page_mapcount(page) |
380 (page->mapping != NULL) |
381 (page_count(page) != 0) |
395 __ClearPageDirty(page);
397 * For now, we report if PG_reserved was found set, but do not
398 * clear it, and do not free the page. But we shall soon need
399 * to do more, for when the ZERO_PAGE count wraps negative.
401 return PageReserved(page);
405 * Frees a list of pages.
406 * Assumes all pages on list are in same zone, and of same order.
407 * count is the number of pages to free.
409 * If the zone was previously in an "all pages pinned" state then look to
410 * see if this freeing clears that state.
412 * And clear the zone's pages_scanned counter, to hold off the "all pages are
413 * pinned" detection logic.
415 static void free_pages_bulk(struct zone *zone, int count,
416 struct list_head *list, int order)
418 spin_lock(&zone->lock);
419 zone->all_unreclaimable = 0;
420 zone->pages_scanned = 0;
424 BUG_ON(list_empty(list));
425 page = list_entry(list->prev, struct page, lru);
426 /* have to delete it as __free_one_page list manipulates */
427 list_del(&page->lru);
428 __free_one_page(page, zone, order);
430 spin_unlock(&zone->lock);
433 static void free_one_page(struct zone *zone, struct page *page, int order)
436 list_add(&page->lru, &list);
437 free_pages_bulk(zone, 1, &list, order);
440 static void __free_pages_ok(struct page *page, unsigned int order)
446 arch_free_page(page, order);
447 if (!PageHighMem(page))
448 mutex_debug_check_no_locks_freed(page_address(page),
451 for (i = 0 ; i < (1 << order) ; ++i)
452 reserved += free_pages_check(page + i);
456 kernel_map_pages(page, 1 << order, 0);
457 local_irq_save(flags);
458 __mod_page_state(pgfree, 1 << order);
459 free_one_page(page_zone(page), page, order);
460 local_irq_restore(flags);
464 * permit the bootmem allocator to evade page validation on high-order frees
466 void fastcall __init __free_pages_bootmem(struct page *page, unsigned int order)
469 __ClearPageReserved(page);
470 set_page_count(page, 0);
471 set_page_refcounted(page);
477 for (loop = 0; loop < BITS_PER_LONG; loop++) {
478 struct page *p = &page[loop];
480 if (loop + 1 < BITS_PER_LONG)
482 __ClearPageReserved(p);
483 set_page_count(p, 0);
486 set_page_refcounted(page);
487 __free_pages(page, order);
493 * The order of subdivision here is critical for the IO subsystem.
494 * Please do not alter this order without good reasons and regression
495 * testing. Specifically, as large blocks of memory are subdivided,
496 * the order in which smaller blocks are delivered depends on the order
497 * they're subdivided in this function. This is the primary factor
498 * influencing the order in which pages are delivered to the IO
499 * subsystem according to empirical testing, and this is also justified
500 * by considering the behavior of a buddy system containing a single
501 * large block of memory acted on by a series of small allocations.
502 * This behavior is a critical factor in sglist merging's success.
506 static inline void expand(struct zone *zone, struct page *page,
507 int low, int high, struct free_area *area)
509 unsigned long size = 1 << high;
515 BUG_ON(bad_range(zone, &page[size]));
516 list_add(&page[size].lru, &area->free_list);
518 set_page_order(&page[size], high);
523 * This page is about to be returned from the page allocator
525 static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
527 if (unlikely(page_mapcount(page) |
528 (page->mapping != NULL) |
529 (page_count(page) != 0) |
545 * For now, we report if PG_reserved was found set, but do not
546 * clear it, and do not allocate the page: as a safety net.
548 if (PageReserved(page))
551 page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
552 1 << PG_referenced | 1 << PG_arch_1 |
553 1 << PG_checked | 1 << PG_mappedtodisk);
554 set_page_private(page, 0);
555 set_page_refcounted(page);
556 kernel_map_pages(page, 1 << order, 1);
558 if (gfp_flags & __GFP_ZERO)
559 prep_zero_page(page, order, gfp_flags);
561 if (order && (gfp_flags & __GFP_COMP))
562 prep_compound_page(page, order);
568 * Do the hard work of removing an element from the buddy allocator.
569 * Call me with the zone->lock already held.
571 static struct page *__rmqueue(struct zone *zone, unsigned int order)
573 struct free_area * area;
574 unsigned int current_order;
577 for (current_order = order; current_order < MAX_ORDER; ++current_order) {
578 area = zone->free_area + current_order;
579 if (list_empty(&area->free_list))
582 page = list_entry(area->free_list.next, struct page, lru);
583 list_del(&page->lru);
584 rmv_page_order(page);
586 zone->free_pages -= 1UL << order;
587 expand(zone, page, order, current_order, area);
595 * Obtain a specified number of elements from the buddy allocator, all under
596 * a single hold of the lock, for efficiency. Add them to the supplied list.
597 * Returns the number of new pages which were placed at *list.
599 static int rmqueue_bulk(struct zone *zone, unsigned int order,
600 unsigned long count, struct list_head *list)
604 spin_lock(&zone->lock);
605 for (i = 0; i < count; ++i) {
606 struct page *page = __rmqueue(zone, order);
607 if (unlikely(page == NULL))
609 list_add_tail(&page->lru, list);
611 spin_unlock(&zone->lock);
617 * Called from the slab reaper to drain pagesets on a particular node that
618 * belong to the currently executing processor.
619 * Note that this function must be called with the thread pinned to
620 * a single processor.
622 void drain_node_pages(int nodeid)
627 for (z = 0; z < MAX_NR_ZONES; z++) {
628 struct zone *zone = NODE_DATA(nodeid)->node_zones + z;
629 struct per_cpu_pageset *pset;
631 pset = zone_pcp(zone, smp_processor_id());
632 for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
633 struct per_cpu_pages *pcp;
637 local_irq_save(flags);
638 free_pages_bulk(zone, pcp->count, &pcp->list, 0);
640 local_irq_restore(flags);
647 #if defined(CONFIG_PM) || defined(CONFIG_HOTPLUG_CPU)
648 static void __drain_pages(unsigned int cpu)
654 for_each_zone(zone) {
655 struct per_cpu_pageset *pset;
657 pset = zone_pcp(zone, cpu);
658 for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
659 struct per_cpu_pages *pcp;
662 local_irq_save(flags);
663 free_pages_bulk(zone, pcp->count, &pcp->list, 0);
665 local_irq_restore(flags);
669 #endif /* CONFIG_PM || CONFIG_HOTPLUG_CPU */
673 void mark_free_pages(struct zone *zone)
675 unsigned long zone_pfn, flags;
677 struct list_head *curr;
679 if (!zone->spanned_pages)
682 spin_lock_irqsave(&zone->lock, flags);
683 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
684 ClearPageNosaveFree(pfn_to_page(zone_pfn + zone->zone_start_pfn));
686 for (order = MAX_ORDER - 1; order >= 0; --order)
687 list_for_each(curr, &zone->free_area[order].free_list) {
688 unsigned long start_pfn, i;
690 start_pfn = page_to_pfn(list_entry(curr, struct page, lru));
692 for (i=0; i < (1<<order); i++)
693 SetPageNosaveFree(pfn_to_page(start_pfn+i));
695 spin_unlock_irqrestore(&zone->lock, flags);
699 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
701 void drain_local_pages(void)
705 local_irq_save(flags);
706 __drain_pages(smp_processor_id());
707 local_irq_restore(flags);
709 #endif /* CONFIG_PM */
711 static void zone_statistics(struct zonelist *zonelist, struct zone *z, int cpu)
714 pg_data_t *pg = z->zone_pgdat;
715 pg_data_t *orig = zonelist->zones[0]->zone_pgdat;
716 struct per_cpu_pageset *p;
718 p = zone_pcp(z, cpu);
723 zone_pcp(zonelist->zones[0], cpu)->numa_foreign++;
725 if (pg == NODE_DATA(numa_node_id()))
733 * Free a 0-order page
735 static void fastcall free_hot_cold_page(struct page *page, int cold)
737 struct zone *zone = page_zone(page);
738 struct per_cpu_pages *pcp;
741 arch_free_page(page, 0);
744 page->mapping = NULL;
745 if (free_pages_check(page))
748 kernel_map_pages(page, 1, 0);
750 pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
751 local_irq_save(flags);
752 __inc_page_state(pgfree);
753 list_add(&page->lru, &pcp->list);
755 if (pcp->count >= pcp->high) {
756 free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
757 pcp->count -= pcp->batch;
759 local_irq_restore(flags);
763 void fastcall free_hot_page(struct page *page)
765 free_hot_cold_page(page, 0);
768 void fastcall free_cold_page(struct page *page)
770 free_hot_cold_page(page, 1);
774 * split_page takes a non-compound higher-order page, and splits it into
775 * n (1<<order) sub-pages: page[0..n]
776 * Each sub-page must be freed individually.
778 * Note: this is probably too low level an operation for use in drivers.
779 * Please consult with lkml before using this in your driver.
781 void split_page(struct page *page, unsigned int order)
785 BUG_ON(PageCompound(page));
786 BUG_ON(!page_count(page));
787 for (i = 1; i < (1 << order); i++)
788 set_page_refcounted(page + i);
792 * Really, prep_compound_page() should be called from __rmqueue_bulk(). But
793 * we cheat by calling it from here, in the order > 0 path. Saves a branch
796 static struct page *buffered_rmqueue(struct zonelist *zonelist,
797 struct zone *zone, int order, gfp_t gfp_flags)
801 int cold = !!(gfp_flags & __GFP_COLD);
806 if (likely(order == 0)) {
807 struct per_cpu_pages *pcp;
809 pcp = &zone_pcp(zone, cpu)->pcp[cold];
810 local_irq_save(flags);
812 pcp->count += rmqueue_bulk(zone, 0,
813 pcp->batch, &pcp->list);
814 if (unlikely(!pcp->count))
817 page = list_entry(pcp->list.next, struct page, lru);
818 list_del(&page->lru);
821 spin_lock_irqsave(&zone->lock, flags);
822 page = __rmqueue(zone, order);
823 spin_unlock(&zone->lock);
828 __mod_page_state_zone(zone, pgalloc, 1 << order);
829 zone_statistics(zonelist, zone, cpu);
830 local_irq_restore(flags);
833 BUG_ON(bad_range(zone, page));
834 if (prep_new_page(page, order, gfp_flags))
839 local_irq_restore(flags);
844 #define ALLOC_NO_WATERMARKS 0x01 /* don't check watermarks at all */
845 #define ALLOC_WMARK_MIN 0x02 /* use pages_min watermark */
846 #define ALLOC_WMARK_LOW 0x04 /* use pages_low watermark */
847 #define ALLOC_WMARK_HIGH 0x08 /* use pages_high watermark */
848 #define ALLOC_HARDER 0x10 /* try to alloc harder */
849 #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
850 #define ALLOC_CPUSET 0x40 /* check for correct cpuset */
853 * Return 1 if free pages are above 'mark'. This takes into account the order
856 int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
857 int classzone_idx, int alloc_flags)
859 /* free_pages my go negative - that's OK */
860 long min = mark, free_pages = z->free_pages - (1 << order) + 1;
863 if (alloc_flags & ALLOC_HIGH)
865 if (alloc_flags & ALLOC_HARDER)
868 if (free_pages <= min + z->lowmem_reserve[classzone_idx])
870 for (o = 0; o < order; o++) {
871 /* At the next order, this order's pages become unavailable */
872 free_pages -= z->free_area[o].nr_free << o;
874 /* Require fewer higher order pages to be free */
877 if (free_pages <= min)
884 * get_page_from_freeliest goes through the zonelist trying to allocate
888 get_page_from_freelist(gfp_t gfp_mask, unsigned int order,
889 struct zonelist *zonelist, int alloc_flags)
891 struct zone **z = zonelist->zones;
892 struct page *page = NULL;
893 int classzone_idx = zone_idx(*z);
896 * Go through the zonelist once, looking for a zone with enough free.
897 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
900 if ((alloc_flags & ALLOC_CPUSET) &&
901 !cpuset_zone_allowed(*z, gfp_mask))
904 if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
906 if (alloc_flags & ALLOC_WMARK_MIN)
907 mark = (*z)->pages_min;
908 else if (alloc_flags & ALLOC_WMARK_LOW)
909 mark = (*z)->pages_low;
911 mark = (*z)->pages_high;
912 if (!zone_watermark_ok(*z, order, mark,
913 classzone_idx, alloc_flags))
914 if (!zone_reclaim_mode ||
915 !zone_reclaim(*z, gfp_mask, order))
919 page = buffered_rmqueue(zonelist, *z, order, gfp_mask);
923 } while (*(++z) != NULL);
928 * This is the 'heart' of the zoned buddy allocator.
930 struct page * fastcall
931 __alloc_pages(gfp_t gfp_mask, unsigned int order,
932 struct zonelist *zonelist)
934 const gfp_t wait = gfp_mask & __GFP_WAIT;
937 struct reclaim_state reclaim_state;
938 struct task_struct *p = current;
941 int did_some_progress;
943 might_sleep_if(wait);
946 z = zonelist->zones; /* the list of zones suitable for gfp_mask */
948 if (unlikely(*z == NULL)) {
949 /* Should this ever happen?? */
953 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
954 zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET);
959 if (cpuset_zone_allowed(*z, gfp_mask|__GFP_HARDWALL))
960 wakeup_kswapd(*z, order);
964 * OK, we're below the kswapd watermark and have kicked background
965 * reclaim. Now things get more complex, so set up alloc_flags according
966 * to how we want to proceed.
968 * The caller may dip into page reserves a bit more if the caller
969 * cannot run direct reclaim, or if the caller has realtime scheduling
970 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
971 * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
973 alloc_flags = ALLOC_WMARK_MIN;
974 if ((unlikely(rt_task(p)) && !in_interrupt()) || !wait)
975 alloc_flags |= ALLOC_HARDER;
976 if (gfp_mask & __GFP_HIGH)
977 alloc_flags |= ALLOC_HIGH;
979 alloc_flags |= ALLOC_CPUSET;
982 * Go through the zonelist again. Let __GFP_HIGH and allocations
983 * coming from realtime tasks go deeper into reserves.
985 * This is the last chance, in general, before the goto nopage.
986 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
987 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
989 page = get_page_from_freelist(gfp_mask, order, zonelist, alloc_flags);
993 /* This allocation should allow future memory freeing. */
995 if (((p->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE)))
996 && !in_interrupt()) {
997 if (!(gfp_mask & __GFP_NOMEMALLOC)) {
999 /* go through the zonelist yet again, ignoring mins */
1000 page = get_page_from_freelist(gfp_mask, order,
1001 zonelist, ALLOC_NO_WATERMARKS);
1004 if (gfp_mask & __GFP_NOFAIL) {
1005 blk_congestion_wait(WRITE, HZ/50);
1012 /* Atomic allocations - we can't balance anything */
1019 /* We now go into synchronous reclaim */
1020 cpuset_memory_pressure_bump();
1021 p->flags |= PF_MEMALLOC;
1022 reclaim_state.reclaimed_slab = 0;
1023 p->reclaim_state = &reclaim_state;
1025 did_some_progress = try_to_free_pages(zonelist->zones, gfp_mask);
1027 p->reclaim_state = NULL;
1028 p->flags &= ~PF_MEMALLOC;
1032 if (likely(did_some_progress)) {
1033 page = get_page_from_freelist(gfp_mask, order,
1034 zonelist, alloc_flags);
1037 } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
1039 * Go through the zonelist yet one more time, keep
1040 * very high watermark here, this is only to catch
1041 * a parallel oom killing, we must fail if we're still
1042 * under heavy pressure.
1044 page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
1045 zonelist, ALLOC_WMARK_HIGH|ALLOC_CPUSET);
1049 out_of_memory(zonelist, gfp_mask, order);
1054 * Don't let big-order allocations loop unless the caller explicitly
1055 * requests that. Wait for some write requests to complete then retry.
1057 * In this implementation, __GFP_REPEAT means __GFP_NOFAIL for order
1058 * <= 3, but that may not be true in other implementations.
1061 if (!(gfp_mask & __GFP_NORETRY)) {
1062 if ((order <= 3) || (gfp_mask & __GFP_REPEAT))
1064 if (gfp_mask & __GFP_NOFAIL)
1068 blk_congestion_wait(WRITE, HZ/50);
1073 if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
1074 printk(KERN_WARNING "%s: page allocation failure."
1075 " order:%d, mode:0x%x\n",
1076 p->comm, order, gfp_mask);
1084 EXPORT_SYMBOL(__alloc_pages);
1087 * Common helper functions.
1089 fastcall unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
1092 page = alloc_pages(gfp_mask, order);
1095 return (unsigned long) page_address(page);
1098 EXPORT_SYMBOL(__get_free_pages);
1100 fastcall unsigned long get_zeroed_page(gfp_t gfp_mask)
1105 * get_zeroed_page() returns a 32-bit address, which cannot represent
1108 BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
1110 page = alloc_pages(gfp_mask | __GFP_ZERO, 0);
1112 return (unsigned long) page_address(page);
1116 EXPORT_SYMBOL(get_zeroed_page);
1118 void __pagevec_free(struct pagevec *pvec)
1120 int i = pagevec_count(pvec);
1123 free_hot_cold_page(pvec->pages[i], pvec->cold);
1126 fastcall void __free_pages(struct page *page, unsigned int order)
1128 if (put_page_testzero(page)) {
1130 free_hot_page(page);
1132 __free_pages_ok(page, order);
1136 EXPORT_SYMBOL(__free_pages);
1138 fastcall void free_pages(unsigned long addr, unsigned int order)
1141 BUG_ON(!virt_addr_valid((void *)addr));
1142 __free_pages(virt_to_page((void *)addr), order);
1146 EXPORT_SYMBOL(free_pages);
1149 * Total amount of free (allocatable) RAM:
1151 unsigned int nr_free_pages(void)
1153 unsigned int sum = 0;
1157 sum += zone->free_pages;
1162 EXPORT_SYMBOL(nr_free_pages);
1165 unsigned int nr_free_pages_pgdat(pg_data_t *pgdat)
1167 unsigned int i, sum = 0;
1169 for (i = 0; i < MAX_NR_ZONES; i++)
1170 sum += pgdat->node_zones[i].free_pages;
1176 static unsigned int nr_free_zone_pages(int offset)
1178 /* Just pick one node, since fallback list is circular */
1179 pg_data_t *pgdat = NODE_DATA(numa_node_id());
1180 unsigned int sum = 0;
1182 struct zonelist *zonelist = pgdat->node_zonelists + offset;
1183 struct zone **zonep = zonelist->zones;
1186 for (zone = *zonep++; zone; zone = *zonep++) {
1187 unsigned long size = zone->present_pages;
1188 unsigned long high = zone->pages_high;
1197 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
1199 unsigned int nr_free_buffer_pages(void)
1201 return nr_free_zone_pages(gfp_zone(GFP_USER));
1205 * Amount of free RAM allocatable within all zones
1207 unsigned int nr_free_pagecache_pages(void)
1209 return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER));
1212 #ifdef CONFIG_HIGHMEM
1213 unsigned int nr_free_highpages (void)
1216 unsigned int pages = 0;
1218 for_each_online_pgdat(pgdat)
1219 pages += pgdat->node_zones[ZONE_HIGHMEM].free_pages;
1226 static void show_node(struct zone *zone)
1228 printk("Node %d ", zone->zone_pgdat->node_id);
1231 #define show_node(zone) do { } while (0)
1235 * Accumulate the page_state information across all CPUs.
1236 * The result is unavoidably approximate - it can change
1237 * during and after execution of this function.
1239 static DEFINE_PER_CPU(struct page_state, page_states) = {0};
1241 atomic_t nr_pagecache = ATOMIC_INIT(0);
1242 EXPORT_SYMBOL(nr_pagecache);
1244 DEFINE_PER_CPU(long, nr_pagecache_local) = 0;
1247 static void __get_page_state(struct page_state *ret, int nr, cpumask_t *cpumask)
1251 memset(ret, 0, nr * sizeof(unsigned long));
1252 cpus_and(*cpumask, *cpumask, cpu_online_map);
1254 for_each_cpu_mask(cpu, *cpumask) {
1260 in = (unsigned long *)&per_cpu(page_states, cpu);
1262 next_cpu = next_cpu(cpu, *cpumask);
1263 if (likely(next_cpu < NR_CPUS))
1264 prefetch(&per_cpu(page_states, next_cpu));
1266 out = (unsigned long *)ret;
1267 for (off = 0; off < nr; off++)
1272 void get_page_state_node(struct page_state *ret, int node)
1275 cpumask_t mask = node_to_cpumask(node);
1277 nr = offsetof(struct page_state, GET_PAGE_STATE_LAST);
1278 nr /= sizeof(unsigned long);
1280 __get_page_state(ret, nr+1, &mask);
1283 void get_page_state(struct page_state *ret)
1286 cpumask_t mask = CPU_MASK_ALL;
1288 nr = offsetof(struct page_state, GET_PAGE_STATE_LAST);
1289 nr /= sizeof(unsigned long);
1291 __get_page_state(ret, nr + 1, &mask);
1294 void get_full_page_state(struct page_state *ret)
1296 cpumask_t mask = CPU_MASK_ALL;
1298 __get_page_state(ret, sizeof(*ret) / sizeof(unsigned long), &mask);
1301 unsigned long read_page_state_offset(unsigned long offset)
1303 unsigned long ret = 0;
1306 for_each_online_cpu(cpu) {
1309 in = (unsigned long)&per_cpu(page_states, cpu) + offset;
1310 ret += *((unsigned long *)in);
1315 void __mod_page_state_offset(unsigned long offset, unsigned long delta)
1319 ptr = &__get_cpu_var(page_states);
1320 *(unsigned long *)(ptr + offset) += delta;
1322 EXPORT_SYMBOL(__mod_page_state_offset);
1324 void mod_page_state_offset(unsigned long offset, unsigned long delta)
1326 unsigned long flags;
1329 local_irq_save(flags);
1330 ptr = &__get_cpu_var(page_states);
1331 *(unsigned long *)(ptr + offset) += delta;
1332 local_irq_restore(flags);
1334 EXPORT_SYMBOL(mod_page_state_offset);
1336 void __get_zone_counts(unsigned long *active, unsigned long *inactive,
1337 unsigned long *free, struct pglist_data *pgdat)
1339 struct zone *zones = pgdat->node_zones;
1345 for (i = 0; i < MAX_NR_ZONES; i++) {
1346 *active += zones[i].nr_active;
1347 *inactive += zones[i].nr_inactive;
1348 *free += zones[i].free_pages;
1352 void get_zone_counts(unsigned long *active,
1353 unsigned long *inactive, unsigned long *free)
1355 struct pglist_data *pgdat;
1360 for_each_online_pgdat(pgdat) {
1361 unsigned long l, m, n;
1362 __get_zone_counts(&l, &m, &n, pgdat);
1369 void si_meminfo(struct sysinfo *val)
1371 val->totalram = totalram_pages;
1373 val->freeram = nr_free_pages();
1374 val->bufferram = nr_blockdev_pages();
1375 #ifdef CONFIG_HIGHMEM
1376 val->totalhigh = totalhigh_pages;
1377 val->freehigh = nr_free_highpages();
1382 val->mem_unit = PAGE_SIZE;
1385 EXPORT_SYMBOL(si_meminfo);
1388 void si_meminfo_node(struct sysinfo *val, int nid)
1390 pg_data_t *pgdat = NODE_DATA(nid);
1392 val->totalram = pgdat->node_present_pages;
1393 val->freeram = nr_free_pages_pgdat(pgdat);
1394 val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
1395 val->freehigh = pgdat->node_zones[ZONE_HIGHMEM].free_pages;
1396 val->mem_unit = PAGE_SIZE;
1400 #define K(x) ((x) << (PAGE_SHIFT-10))
1403 * Show free area list (used inside shift_scroll-lock stuff)
1404 * We also calculate the percentage fragmentation. We do this by counting the
1405 * memory on each free list with the exception of the first item on the list.
1407 void show_free_areas(void)
1409 struct page_state ps;
1410 int cpu, temperature;
1411 unsigned long active;
1412 unsigned long inactive;
1416 for_each_zone(zone) {
1418 printk("%s per-cpu:", zone->name);
1420 if (!populated_zone(zone)) {
1426 for_each_online_cpu(cpu) {
1427 struct per_cpu_pageset *pageset;
1429 pageset = zone_pcp(zone, cpu);
1431 for (temperature = 0; temperature < 2; temperature++)
1432 printk("cpu %d %s: high %d, batch %d used:%d\n",
1434 temperature ? "cold" : "hot",
1435 pageset->pcp[temperature].high,
1436 pageset->pcp[temperature].batch,
1437 pageset->pcp[temperature].count);
1441 get_page_state(&ps);
1442 get_zone_counts(&active, &inactive, &free);
1444 printk("Free pages: %11ukB (%ukB HighMem)\n",
1446 K(nr_free_highpages()));
1448 printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu "
1449 "unstable:%lu free:%u slab:%lu mapped:%lu pagetables:%lu\n",
1458 ps.nr_page_table_pages);
1460 for_each_zone(zone) {
1472 " pages_scanned:%lu"
1473 " all_unreclaimable? %s"
1476 K(zone->free_pages),
1479 K(zone->pages_high),
1481 K(zone->nr_inactive),
1482 K(zone->present_pages),
1483 zone->pages_scanned,
1484 (zone->all_unreclaimable ? "yes" : "no")
1486 printk("lowmem_reserve[]:");
1487 for (i = 0; i < MAX_NR_ZONES; i++)
1488 printk(" %lu", zone->lowmem_reserve[i]);
1492 for_each_zone(zone) {
1493 unsigned long nr, flags, order, total = 0;
1496 printk("%s: ", zone->name);
1497 if (!populated_zone(zone)) {
1502 spin_lock_irqsave(&zone->lock, flags);
1503 for (order = 0; order < MAX_ORDER; order++) {
1504 nr = zone->free_area[order].nr_free;
1505 total += nr << order;
1506 printk("%lu*%lukB ", nr, K(1UL) << order);
1508 spin_unlock_irqrestore(&zone->lock, flags);
1509 printk("= %lukB\n", K(total));
1512 show_swap_cache_info();
1516 * Builds allocation fallback zone lists.
1518 * Add all populated zones of a node to the zonelist.
1520 static int __meminit build_zonelists_node(pg_data_t *pgdat,
1521 struct zonelist *zonelist, int nr_zones, int zone_type)
1525 BUG_ON(zone_type > ZONE_HIGHMEM);
1528 zone = pgdat->node_zones + zone_type;
1529 if (populated_zone(zone)) {
1530 #ifndef CONFIG_HIGHMEM
1531 BUG_ON(zone_type > ZONE_NORMAL);
1533 zonelist->zones[nr_zones++] = zone;
1534 check_highest_zone(zone_type);
1538 } while (zone_type >= 0);
1542 static inline int highest_zone(int zone_bits)
1544 int res = ZONE_NORMAL;
1545 if (zone_bits & (__force int)__GFP_HIGHMEM)
1547 if (zone_bits & (__force int)__GFP_DMA32)
1549 if (zone_bits & (__force int)__GFP_DMA)
1555 #define MAX_NODE_LOAD (num_online_nodes())
1556 static int __meminitdata node_load[MAX_NUMNODES];
1558 * find_next_best_node - find the next node that should appear in a given node's fallback list
1559 * @node: node whose fallback list we're appending
1560 * @used_node_mask: nodemask_t of already used nodes
1562 * We use a number of factors to determine which is the next node that should
1563 * appear on a given node's fallback list. The node should not have appeared
1564 * already in @node's fallback list, and it should be the next closest node
1565 * according to the distance array (which contains arbitrary distance values
1566 * from each node to each node in the system), and should also prefer nodes
1567 * with no CPUs, since presumably they'll have very little allocation pressure
1568 * on them otherwise.
1569 * It returns -1 if no node is found.
1571 static int __meminit find_next_best_node(int node, nodemask_t *used_node_mask)
1574 int min_val = INT_MAX;
1577 /* Use the local node if we haven't already */
1578 if (!node_isset(node, *used_node_mask)) {
1579 node_set(node, *used_node_mask);
1583 for_each_online_node(n) {
1586 /* Don't want a node to appear more than once */
1587 if (node_isset(n, *used_node_mask))
1590 /* Use the distance array to find the distance */
1591 val = node_distance(node, n);
1593 /* Penalize nodes under us ("prefer the next node") */
1596 /* Give preference to headless and unused nodes */
1597 tmp = node_to_cpumask(n);
1598 if (!cpus_empty(tmp))
1599 val += PENALTY_FOR_NODE_WITH_CPUS;
1601 /* Slight preference for less loaded node */
1602 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
1603 val += node_load[n];
1605 if (val < min_val) {
1612 node_set(best_node, *used_node_mask);
1617 static void __meminit build_zonelists(pg_data_t *pgdat)
1619 int i, j, k, node, local_node;
1620 int prev_node, load;
1621 struct zonelist *zonelist;
1622 nodemask_t used_mask;
1624 /* initialize zonelists */
1625 for (i = 0; i < GFP_ZONETYPES; i++) {
1626 zonelist = pgdat->node_zonelists + i;
1627 zonelist->zones[0] = NULL;
1630 /* NUMA-aware ordering of nodes */
1631 local_node = pgdat->node_id;
1632 load = num_online_nodes();
1633 prev_node = local_node;
1634 nodes_clear(used_mask);
1635 while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
1636 int distance = node_distance(local_node, node);
1639 * If another node is sufficiently far away then it is better
1640 * to reclaim pages in a zone before going off node.
1642 if (distance > RECLAIM_DISTANCE)
1643 zone_reclaim_mode = 1;
1646 * We don't want to pressure a particular node.
1647 * So adding penalty to the first node in same
1648 * distance group to make it round-robin.
1651 if (distance != node_distance(local_node, prev_node))
1652 node_load[node] += load;
1655 for (i = 0; i < GFP_ZONETYPES; i++) {
1656 zonelist = pgdat->node_zonelists + i;
1657 for (j = 0; zonelist->zones[j] != NULL; j++);
1659 k = highest_zone(i);
1661 j = build_zonelists_node(NODE_DATA(node), zonelist, j, k);
1662 zonelist->zones[j] = NULL;
1667 #else /* CONFIG_NUMA */
1669 static void __meminit build_zonelists(pg_data_t *pgdat)
1671 int i, j, k, node, local_node;
1673 local_node = pgdat->node_id;
1674 for (i = 0; i < GFP_ZONETYPES; i++) {
1675 struct zonelist *zonelist;
1677 zonelist = pgdat->node_zonelists + i;
1680 k = highest_zone(i);
1681 j = build_zonelists_node(pgdat, zonelist, j, k);
1683 * Now we build the zonelist so that it contains the zones
1684 * of all the other nodes.
1685 * We don't want to pressure a particular node, so when
1686 * building the zones for node N, we make sure that the
1687 * zones coming right after the local ones are those from
1688 * node N+1 (modulo N)
1690 for (node = local_node + 1; node < MAX_NUMNODES; node++) {
1691 if (!node_online(node))
1693 j = build_zonelists_node(NODE_DATA(node), zonelist, j, k);
1695 for (node = 0; node < local_node; node++) {
1696 if (!node_online(node))
1698 j = build_zonelists_node(NODE_DATA(node), zonelist, j, k);
1701 zonelist->zones[j] = NULL;
1705 #endif /* CONFIG_NUMA */
1707 void __init build_all_zonelists(void)
1711 for_each_online_node(i)
1712 build_zonelists(NODE_DATA(i));
1713 printk("Built %i zonelists\n", num_online_nodes());
1714 cpuset_init_current_mems_allowed();
1718 * Helper functions to size the waitqueue hash table.
1719 * Essentially these want to choose hash table sizes sufficiently
1720 * large so that collisions trying to wait on pages are rare.
1721 * But in fact, the number of active page waitqueues on typical
1722 * systems is ridiculously low, less than 200. So this is even
1723 * conservative, even though it seems large.
1725 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
1726 * waitqueues, i.e. the size of the waitq table given the number of pages.
1728 #define PAGES_PER_WAITQUEUE 256
1730 #ifndef CONFIG_MEMORY_HOTPLUG
1731 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
1733 unsigned long size = 1;
1735 pages /= PAGES_PER_WAITQUEUE;
1737 while (size < pages)
1741 * Once we have dozens or even hundreds of threads sleeping
1742 * on IO we've got bigger problems than wait queue collision.
1743 * Limit the size of the wait table to a reasonable size.
1745 size = min(size, 4096UL);
1747 return max(size, 4UL);
1751 * A zone's size might be changed by hot-add, so it is not possible to determine
1752 * a suitable size for its wait_table. So we use the maximum size now.
1754 * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie:
1756 * i386 (preemption config) : 4096 x 16 = 64Kbyte.
1757 * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
1758 * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte.
1760 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
1761 * or more by the traditional way. (See above). It equals:
1763 * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte.
1764 * ia64(16K page size) : = ( 8G + 4M)byte.
1765 * powerpc (64K page size) : = (32G +16M)byte.
1767 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
1774 * This is an integer logarithm so that shifts can be used later
1775 * to extract the more random high bits from the multiplicative
1776 * hash function before the remainder is taken.
1778 static inline unsigned long wait_table_bits(unsigned long size)
1783 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
1785 static void __init calculate_zone_totalpages(struct pglist_data *pgdat,
1786 unsigned long *zones_size, unsigned long *zholes_size)
1788 unsigned long realtotalpages, totalpages = 0;
1791 for (i = 0; i < MAX_NR_ZONES; i++)
1792 totalpages += zones_size[i];
1793 pgdat->node_spanned_pages = totalpages;
1795 realtotalpages = totalpages;
1797 for (i = 0; i < MAX_NR_ZONES; i++)
1798 realtotalpages -= zholes_size[i];
1799 pgdat->node_present_pages = realtotalpages;
1800 printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id, realtotalpages);
1805 * Initially all pages are reserved - free ones are freed
1806 * up by free_all_bootmem() once the early boot process is
1807 * done. Non-atomic initialization, single-pass.
1809 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
1810 unsigned long start_pfn)
1813 unsigned long end_pfn = start_pfn + size;
1816 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1817 if (!early_pfn_valid(pfn))
1819 page = pfn_to_page(pfn);
1820 set_page_links(page, zone, nid, pfn);
1821 init_page_count(page);
1822 reset_page_mapcount(page);
1823 SetPageReserved(page);
1824 INIT_LIST_HEAD(&page->lru);
1825 #ifdef WANT_PAGE_VIRTUAL
1826 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
1827 if (!is_highmem_idx(zone))
1828 set_page_address(page, __va(pfn << PAGE_SHIFT));
1833 void zone_init_free_lists(struct pglist_data *pgdat, struct zone *zone,
1837 for (order = 0; order < MAX_ORDER ; order++) {
1838 INIT_LIST_HEAD(&zone->free_area[order].free_list);
1839 zone->free_area[order].nr_free = 0;
1843 #define ZONETABLE_INDEX(x, zone_nr) ((x << ZONES_SHIFT) | zone_nr)
1844 void zonetable_add(struct zone *zone, int nid, int zid, unsigned long pfn,
1847 unsigned long snum = pfn_to_section_nr(pfn);
1848 unsigned long end = pfn_to_section_nr(pfn + size);
1851 zone_table[ZONETABLE_INDEX(nid, zid)] = zone;
1853 for (; snum <= end; snum++)
1854 zone_table[ZONETABLE_INDEX(snum, zid)] = zone;
1857 #ifndef __HAVE_ARCH_MEMMAP_INIT
1858 #define memmap_init(size, nid, zone, start_pfn) \
1859 memmap_init_zone((size), (nid), (zone), (start_pfn))
1862 static int __cpuinit zone_batchsize(struct zone *zone)
1867 * The per-cpu-pages pools are set to around 1000th of the
1868 * size of the zone. But no more than 1/2 of a meg.
1870 * OK, so we don't know how big the cache is. So guess.
1872 batch = zone->present_pages / 1024;
1873 if (batch * PAGE_SIZE > 512 * 1024)
1874 batch = (512 * 1024) / PAGE_SIZE;
1875 batch /= 4; /* We effectively *= 4 below */
1880 * Clamp the batch to a 2^n - 1 value. Having a power
1881 * of 2 value was found to be more likely to have
1882 * suboptimal cache aliasing properties in some cases.
1884 * For example if 2 tasks are alternately allocating
1885 * batches of pages, one task can end up with a lot
1886 * of pages of one half of the possible page colors
1887 * and the other with pages of the other colors.
1889 batch = (1 << (fls(batch + batch/2)-1)) - 1;
1894 inline void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
1896 struct per_cpu_pages *pcp;
1898 memset(p, 0, sizeof(*p));
1900 pcp = &p->pcp[0]; /* hot */
1902 pcp->high = 6 * batch;
1903 pcp->batch = max(1UL, 1 * batch);
1904 INIT_LIST_HEAD(&pcp->list);
1906 pcp = &p->pcp[1]; /* cold*/
1908 pcp->high = 2 * batch;
1909 pcp->batch = max(1UL, batch/2);
1910 INIT_LIST_HEAD(&pcp->list);
1914 * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
1915 * to the value high for the pageset p.
1918 static void setup_pagelist_highmark(struct per_cpu_pageset *p,
1921 struct per_cpu_pages *pcp;
1923 pcp = &p->pcp[0]; /* hot list */
1925 pcp->batch = max(1UL, high/4);
1926 if ((high/4) > (PAGE_SHIFT * 8))
1927 pcp->batch = PAGE_SHIFT * 8;
1933 * Boot pageset table. One per cpu which is going to be used for all
1934 * zones and all nodes. The parameters will be set in such a way
1935 * that an item put on a list will immediately be handed over to
1936 * the buddy list. This is safe since pageset manipulation is done
1937 * with interrupts disabled.
1939 * Some NUMA counter updates may also be caught by the boot pagesets.
1941 * The boot_pagesets must be kept even after bootup is complete for
1942 * unused processors and/or zones. They do play a role for bootstrapping
1943 * hotplugged processors.
1945 * zoneinfo_show() and maybe other functions do
1946 * not check if the processor is online before following the pageset pointer.
1947 * Other parts of the kernel may not check if the zone is available.
1949 static struct per_cpu_pageset boot_pageset[NR_CPUS];
1952 * Dynamically allocate memory for the
1953 * per cpu pageset array in struct zone.
1955 static int __cpuinit process_zones(int cpu)
1957 struct zone *zone, *dzone;
1959 for_each_zone(zone) {
1961 zone_pcp(zone, cpu) = kmalloc_node(sizeof(struct per_cpu_pageset),
1962 GFP_KERNEL, cpu_to_node(cpu));
1963 if (!zone_pcp(zone, cpu))
1966 setup_pageset(zone_pcp(zone, cpu), zone_batchsize(zone));
1968 if (percpu_pagelist_fraction)
1969 setup_pagelist_highmark(zone_pcp(zone, cpu),
1970 (zone->present_pages / percpu_pagelist_fraction));
1975 for_each_zone(dzone) {
1978 kfree(zone_pcp(dzone, cpu));
1979 zone_pcp(dzone, cpu) = NULL;
1984 static inline void free_zone_pagesets(int cpu)
1988 for_each_zone(zone) {
1989 struct per_cpu_pageset *pset = zone_pcp(zone, cpu);
1991 zone_pcp(zone, cpu) = NULL;
1996 static int pageset_cpuup_callback(struct notifier_block *nfb,
1997 unsigned long action,
2000 int cpu = (long)hcpu;
2001 int ret = NOTIFY_OK;
2004 case CPU_UP_PREPARE:
2005 if (process_zones(cpu))
2008 case CPU_UP_CANCELED:
2010 free_zone_pagesets(cpu);
2018 static struct notifier_block pageset_notifier =
2019 { &pageset_cpuup_callback, NULL, 0 };
2021 void __init setup_per_cpu_pageset(void)
2025 /* Initialize per_cpu_pageset for cpu 0.
2026 * A cpuup callback will do this for every cpu
2027 * as it comes online
2029 err = process_zones(smp_processor_id());
2031 register_cpu_notifier(&pageset_notifier);
2037 int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
2040 struct pglist_data *pgdat = zone->zone_pgdat;
2044 * The per-page waitqueue mechanism uses hashed waitqueues
2047 zone->wait_table_hash_nr_entries =
2048 wait_table_hash_nr_entries(zone_size_pages);
2049 zone->wait_table_bits =
2050 wait_table_bits(zone->wait_table_hash_nr_entries);
2051 alloc_size = zone->wait_table_hash_nr_entries
2052 * sizeof(wait_queue_head_t);
2054 if (system_state == SYSTEM_BOOTING) {
2055 zone->wait_table = (wait_queue_head_t *)
2056 alloc_bootmem_node(pgdat, alloc_size);
2059 * This case means that a zone whose size was 0 gets new memory
2060 * via memory hot-add.
2061 * But it may be the case that a new node was hot-added. In
2062 * this case vmalloc() will not be able to use this new node's
2063 * memory - this wait_table must be initialized to use this new
2064 * node itself as well.
2065 * To use this new node's memory, further consideration will be
2068 zone->wait_table = (wait_queue_head_t *)vmalloc(alloc_size);
2070 if (!zone->wait_table)
2073 for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
2074 init_waitqueue_head(zone->wait_table + i);
2079 static __meminit void zone_pcp_init(struct zone *zone)
2082 unsigned long batch = zone_batchsize(zone);
2084 for (cpu = 0; cpu < NR_CPUS; cpu++) {
2086 /* Early boot. Slab allocator not functional yet */
2087 zone_pcp(zone, cpu) = &boot_pageset[cpu];
2088 setup_pageset(&boot_pageset[cpu],0);
2090 setup_pageset(zone_pcp(zone,cpu), batch);
2093 if (zone->present_pages)
2094 printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%lu\n",
2095 zone->name, zone->present_pages, batch);
2098 __meminit int init_currently_empty_zone(struct zone *zone,
2099 unsigned long zone_start_pfn,
2102 struct pglist_data *pgdat = zone->zone_pgdat;
2104 ret = zone_wait_table_init(zone, size);
2107 pgdat->nr_zones = zone_idx(zone) + 1;
2109 zone->zone_start_pfn = zone_start_pfn;
2111 memmap_init(size, pgdat->node_id, zone_idx(zone), zone_start_pfn);
2113 zone_init_free_lists(pgdat, zone, zone->spanned_pages);
2119 * Set up the zone data structures:
2120 * - mark all pages reserved
2121 * - mark all memory queues empty
2122 * - clear the memory bitmaps
2124 static void __meminit free_area_init_core(struct pglist_data *pgdat,
2125 unsigned long *zones_size, unsigned long *zholes_size)
2128 int nid = pgdat->node_id;
2129 unsigned long zone_start_pfn = pgdat->node_start_pfn;
2132 pgdat_resize_init(pgdat);
2133 pgdat->nr_zones = 0;
2134 init_waitqueue_head(&pgdat->kswapd_wait);
2135 pgdat->kswapd_max_order = 0;
2137 for (j = 0; j < MAX_NR_ZONES; j++) {
2138 struct zone *zone = pgdat->node_zones + j;
2139 unsigned long size, realsize;
2141 realsize = size = zones_size[j];
2143 realsize -= zholes_size[j];
2145 if (j < ZONE_HIGHMEM)
2146 nr_kernel_pages += realsize;
2147 nr_all_pages += realsize;
2149 zone->spanned_pages = size;
2150 zone->present_pages = realsize;
2151 zone->name = zone_names[j];
2152 spin_lock_init(&zone->lock);
2153 spin_lock_init(&zone->lru_lock);
2154 zone_seqlock_init(zone);
2155 zone->zone_pgdat = pgdat;
2156 zone->free_pages = 0;
2158 zone->temp_priority = zone->prev_priority = DEF_PRIORITY;
2160 zone_pcp_init(zone);
2161 INIT_LIST_HEAD(&zone->active_list);
2162 INIT_LIST_HEAD(&zone->inactive_list);
2163 zone->nr_scan_active = 0;
2164 zone->nr_scan_inactive = 0;
2165 zone->nr_active = 0;
2166 zone->nr_inactive = 0;
2167 atomic_set(&zone->reclaim_in_progress, 0);
2171 zonetable_add(zone, nid, j, zone_start_pfn, size);
2172 ret = init_currently_empty_zone(zone, zone_start_pfn, size);
2174 zone_start_pfn += size;
2178 static void __init alloc_node_mem_map(struct pglist_data *pgdat)
2180 /* Skip empty nodes */
2181 if (!pgdat->node_spanned_pages)
2184 #ifdef CONFIG_FLAT_NODE_MEM_MAP
2185 /* ia64 gets its own node_mem_map, before this, without bootmem */
2186 if (!pgdat->node_mem_map) {
2187 unsigned long size, start, end;
2191 * The zone's endpoints aren't required to be MAX_ORDER
2192 * aligned but the node_mem_map endpoints must be in order
2193 * for the buddy allocator to function correctly.
2195 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
2196 end = pgdat->node_start_pfn + pgdat->node_spanned_pages;
2197 end = ALIGN(end, MAX_ORDER_NR_PAGES);
2198 size = (end - start) * sizeof(struct page);
2199 map = alloc_remap(pgdat->node_id, size);
2201 map = alloc_bootmem_node(pgdat, size);
2202 pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
2204 #ifdef CONFIG_FLATMEM
2206 * With no DISCONTIG, the global mem_map is just set as node 0's
2208 if (pgdat == NODE_DATA(0))
2209 mem_map = NODE_DATA(0)->node_mem_map;
2211 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
2214 void __meminit free_area_init_node(int nid, struct pglist_data *pgdat,
2215 unsigned long *zones_size, unsigned long node_start_pfn,
2216 unsigned long *zholes_size)
2218 pgdat->node_id = nid;
2219 pgdat->node_start_pfn = node_start_pfn;
2220 calculate_zone_totalpages(pgdat, zones_size, zholes_size);
2222 alloc_node_mem_map(pgdat);
2224 free_area_init_core(pgdat, zones_size, zholes_size);
2227 #ifndef CONFIG_NEED_MULTIPLE_NODES
2228 static bootmem_data_t contig_bootmem_data;
2229 struct pglist_data contig_page_data = { .bdata = &contig_bootmem_data };
2231 EXPORT_SYMBOL(contig_page_data);
2234 void __init free_area_init(unsigned long *zones_size)
2236 free_area_init_node(0, NODE_DATA(0), zones_size,
2237 __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
2240 #ifdef CONFIG_PROC_FS
2242 #include <linux/seq_file.h>
2244 static void *frag_start(struct seq_file *m, loff_t *pos)
2248 for (pgdat = first_online_pgdat();
2250 pgdat = next_online_pgdat(pgdat))
2256 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
2258 pg_data_t *pgdat = (pg_data_t *)arg;
2261 return next_online_pgdat(pgdat);
2264 static void frag_stop(struct seq_file *m, void *arg)
2269 * This walks the free areas for each zone.
2271 static int frag_show(struct seq_file *m, void *arg)
2273 pg_data_t *pgdat = (pg_data_t *)arg;
2275 struct zone *node_zones = pgdat->node_zones;
2276 unsigned long flags;
2279 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
2280 if (!populated_zone(zone))
2283 spin_lock_irqsave(&zone->lock, flags);
2284 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
2285 for (order = 0; order < MAX_ORDER; ++order)
2286 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
2287 spin_unlock_irqrestore(&zone->lock, flags);
2293 struct seq_operations fragmentation_op = {
2294 .start = frag_start,
2301 * Output information about zones in @pgdat.
2303 static int zoneinfo_show(struct seq_file *m, void *arg)
2305 pg_data_t *pgdat = arg;
2307 struct zone *node_zones = pgdat->node_zones;
2308 unsigned long flags;
2310 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; zone++) {
2313 if (!populated_zone(zone))
2316 spin_lock_irqsave(&zone->lock, flags);
2317 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
2325 "\n scanned %lu (a: %lu i: %lu)"
2334 zone->pages_scanned,
2335 zone->nr_scan_active, zone->nr_scan_inactive,
2336 zone->spanned_pages,
2337 zone->present_pages);
2339 "\n protection: (%lu",
2340 zone->lowmem_reserve[0]);
2341 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
2342 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
2346 for_each_online_cpu(i) {
2347 struct per_cpu_pageset *pageset;
2350 pageset = zone_pcp(zone, i);
2351 for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
2352 if (pageset->pcp[j].count)
2355 if (j == ARRAY_SIZE(pageset->pcp))
2357 for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
2359 "\n cpu: %i pcp: %i"
2364 pageset->pcp[j].count,
2365 pageset->pcp[j].high,
2366 pageset->pcp[j].batch);
2372 "\n numa_foreign: %lu"
2373 "\n interleave_hit: %lu"
2374 "\n local_node: %lu"
2375 "\n other_node: %lu",
2378 pageset->numa_foreign,
2379 pageset->interleave_hit,
2380 pageset->local_node,
2381 pageset->other_node);
2385 "\n all_unreclaimable: %u"
2386 "\n prev_priority: %i"
2387 "\n temp_priority: %i"
2388 "\n start_pfn: %lu",
2389 zone->all_unreclaimable,
2390 zone->prev_priority,
2391 zone->temp_priority,
2392 zone->zone_start_pfn);
2393 spin_unlock_irqrestore(&zone->lock, flags);
2399 struct seq_operations zoneinfo_op = {
2400 .start = frag_start, /* iterate over all zones. The same as in
2404 .show = zoneinfo_show,
2407 static char *vmstat_text[] = {
2411 "nr_page_table_pages",
2442 "pgscan_kswapd_high",
2443 "pgscan_kswapd_normal",
2444 "pgscan_kswapd_dma32",
2445 "pgscan_kswapd_dma",
2447 "pgscan_direct_high",
2448 "pgscan_direct_normal",
2449 "pgscan_direct_dma32",
2450 "pgscan_direct_dma",
2455 "kswapd_inodesteal",
2463 static void *vmstat_start(struct seq_file *m, loff_t *pos)
2465 struct page_state *ps;
2467 if (*pos >= ARRAY_SIZE(vmstat_text))
2470 ps = kmalloc(sizeof(*ps), GFP_KERNEL);
2473 return ERR_PTR(-ENOMEM);
2474 get_full_page_state(ps);
2475 ps->pgpgin /= 2; /* sectors -> kbytes */
2477 return (unsigned long *)ps + *pos;
2480 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
2483 if (*pos >= ARRAY_SIZE(vmstat_text))
2485 return (unsigned long *)m->private + *pos;
2488 static int vmstat_show(struct seq_file *m, void *arg)
2490 unsigned long *l = arg;
2491 unsigned long off = l - (unsigned long *)m->private;
2493 seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
2497 static void vmstat_stop(struct seq_file *m, void *arg)
2503 struct seq_operations vmstat_op = {
2504 .start = vmstat_start,
2505 .next = vmstat_next,
2506 .stop = vmstat_stop,
2507 .show = vmstat_show,
2510 #endif /* CONFIG_PROC_FS */
2512 #ifdef CONFIG_HOTPLUG_CPU
2513 static int page_alloc_cpu_notify(struct notifier_block *self,
2514 unsigned long action, void *hcpu)
2516 int cpu = (unsigned long)hcpu;
2518 unsigned long *src, *dest;
2520 if (action == CPU_DEAD) {
2523 /* Drain local pagecache count. */
2524 count = &per_cpu(nr_pagecache_local, cpu);
2525 atomic_add(*count, &nr_pagecache);
2527 local_irq_disable();
2530 /* Add dead cpu's page_states to our own. */
2531 dest = (unsigned long *)&__get_cpu_var(page_states);
2532 src = (unsigned long *)&per_cpu(page_states, cpu);
2534 for (i = 0; i < sizeof(struct page_state)/sizeof(unsigned long);
2544 #endif /* CONFIG_HOTPLUG_CPU */
2546 void __init page_alloc_init(void)
2548 hotcpu_notifier(page_alloc_cpu_notify, 0);
2552 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
2553 * or min_free_kbytes changes.
2555 static void calculate_totalreserve_pages(void)
2557 struct pglist_data *pgdat;
2558 unsigned long reserve_pages = 0;
2561 for_each_online_pgdat(pgdat) {
2562 for (i = 0; i < MAX_NR_ZONES; i++) {
2563 struct zone *zone = pgdat->node_zones + i;
2564 unsigned long max = 0;
2566 /* Find valid and maximum lowmem_reserve in the zone */
2567 for (j = i; j < MAX_NR_ZONES; j++) {
2568 if (zone->lowmem_reserve[j] > max)
2569 max = zone->lowmem_reserve[j];
2572 /* we treat pages_high as reserved pages. */
2573 max += zone->pages_high;
2575 if (max > zone->present_pages)
2576 max = zone->present_pages;
2577 reserve_pages += max;
2580 totalreserve_pages = reserve_pages;
2584 * setup_per_zone_lowmem_reserve - called whenever
2585 * sysctl_lower_zone_reserve_ratio changes. Ensures that each zone
2586 * has a correct pages reserved value, so an adequate number of
2587 * pages are left in the zone after a successful __alloc_pages().
2589 static void setup_per_zone_lowmem_reserve(void)
2591 struct pglist_data *pgdat;
2594 for_each_online_pgdat(pgdat) {
2595 for (j = 0; j < MAX_NR_ZONES; j++) {
2596 struct zone *zone = pgdat->node_zones + j;
2597 unsigned long present_pages = zone->present_pages;
2599 zone->lowmem_reserve[j] = 0;
2601 for (idx = j-1; idx >= 0; idx--) {
2602 struct zone *lower_zone;
2604 if (sysctl_lowmem_reserve_ratio[idx] < 1)
2605 sysctl_lowmem_reserve_ratio[idx] = 1;
2607 lower_zone = pgdat->node_zones + idx;
2608 lower_zone->lowmem_reserve[j] = present_pages /
2609 sysctl_lowmem_reserve_ratio[idx];
2610 present_pages += lower_zone->present_pages;
2615 /* update totalreserve_pages */
2616 calculate_totalreserve_pages();
2620 * setup_per_zone_pages_min - called when min_free_kbytes changes. Ensures
2621 * that the pages_{min,low,high} values for each zone are set correctly
2622 * with respect to min_free_kbytes.
2624 void setup_per_zone_pages_min(void)
2626 unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
2627 unsigned long lowmem_pages = 0;
2629 unsigned long flags;
2631 /* Calculate total number of !ZONE_HIGHMEM pages */
2632 for_each_zone(zone) {
2633 if (!is_highmem(zone))
2634 lowmem_pages += zone->present_pages;
2637 for_each_zone(zone) {
2640 spin_lock_irqsave(&zone->lru_lock, flags);
2641 tmp = (u64)pages_min * zone->present_pages;
2642 do_div(tmp, lowmem_pages);
2643 if (is_highmem(zone)) {
2645 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
2646 * need highmem pages, so cap pages_min to a small
2649 * The (pages_high-pages_low) and (pages_low-pages_min)
2650 * deltas controls asynch page reclaim, and so should
2651 * not be capped for highmem.
2655 min_pages = zone->present_pages / 1024;
2656 if (min_pages < SWAP_CLUSTER_MAX)
2657 min_pages = SWAP_CLUSTER_MAX;
2658 if (min_pages > 128)
2660 zone->pages_min = min_pages;
2663 * If it's a lowmem zone, reserve a number of pages
2664 * proportionate to the zone's size.
2666 zone->pages_min = tmp;
2669 zone->pages_low = zone->pages_min + (tmp >> 2);
2670 zone->pages_high = zone->pages_min + (tmp >> 1);
2671 spin_unlock_irqrestore(&zone->lru_lock, flags);
2674 /* update totalreserve_pages */
2675 calculate_totalreserve_pages();
2679 * Initialise min_free_kbytes.
2681 * For small machines we want it small (128k min). For large machines
2682 * we want it large (64MB max). But it is not linear, because network
2683 * bandwidth does not increase linearly with machine size. We use
2685 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
2686 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
2702 static int __init init_per_zone_pages_min(void)
2704 unsigned long lowmem_kbytes;
2706 lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
2708 min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
2709 if (min_free_kbytes < 128)
2710 min_free_kbytes = 128;
2711 if (min_free_kbytes > 65536)
2712 min_free_kbytes = 65536;
2713 setup_per_zone_pages_min();
2714 setup_per_zone_lowmem_reserve();
2717 module_init(init_per_zone_pages_min)
2720 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
2721 * that we can call two helper functions whenever min_free_kbytes
2724 int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
2725 struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
2727 proc_dointvec(table, write, file, buffer, length, ppos);
2728 setup_per_zone_pages_min();
2733 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
2734 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
2735 * whenever sysctl_lowmem_reserve_ratio changes.
2737 * The reserve ratio obviously has absolutely no relation with the
2738 * pages_min watermarks. The lowmem reserve ratio can only make sense
2739 * if in function of the boot time zone sizes.
2741 int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
2742 struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
2744 proc_dointvec_minmax(table, write, file, buffer, length, ppos);
2745 setup_per_zone_lowmem_reserve();
2750 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
2751 * cpu. It is the fraction of total pages in each zone that a hot per cpu pagelist
2752 * can have before it gets flushed back to buddy allocator.
2755 int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
2756 struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
2762 ret = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
2763 if (!write || (ret == -EINVAL))
2765 for_each_zone(zone) {
2766 for_each_online_cpu(cpu) {
2768 high = zone->present_pages / percpu_pagelist_fraction;
2769 setup_pagelist_highmark(zone_pcp(zone, cpu), high);
2775 __initdata int hashdist = HASHDIST_DEFAULT;
2778 static int __init set_hashdist(char *str)
2782 hashdist = simple_strtoul(str, &str, 0);
2785 __setup("hashdist=", set_hashdist);
2789 * allocate a large system hash table from bootmem
2790 * - it is assumed that the hash table must contain an exact power-of-2
2791 * quantity of entries
2792 * - limit is the number of hash buckets, not the total allocation size
2794 void *__init alloc_large_system_hash(const char *tablename,
2795 unsigned long bucketsize,
2796 unsigned long numentries,
2799 unsigned int *_hash_shift,
2800 unsigned int *_hash_mask,
2801 unsigned long limit)
2803 unsigned long long max = limit;
2804 unsigned long log2qty, size;
2807 /* allow the kernel cmdline to have a say */
2809 /* round applicable memory size up to nearest megabyte */
2810 numentries = (flags & HASH_HIGHMEM) ? nr_all_pages : nr_kernel_pages;
2811 numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
2812 numentries >>= 20 - PAGE_SHIFT;
2813 numentries <<= 20 - PAGE_SHIFT;
2815 /* limit to 1 bucket per 2^scale bytes of low memory */
2816 if (scale > PAGE_SHIFT)
2817 numentries >>= (scale - PAGE_SHIFT);
2819 numentries <<= (PAGE_SHIFT - scale);
2821 numentries = roundup_pow_of_two(numentries);
2823 /* limit allocation size to 1/16 total memory by default */
2825 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
2826 do_div(max, bucketsize);
2829 if (numentries > max)
2832 log2qty = long_log2(numentries);
2835 size = bucketsize << log2qty;
2836 if (flags & HASH_EARLY)
2837 table = alloc_bootmem(size);
2839 table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
2841 unsigned long order;
2842 for (order = 0; ((1UL << order) << PAGE_SHIFT) < size; order++)
2844 table = (void*) __get_free_pages(GFP_ATOMIC, order);
2846 } while (!table && size > PAGE_SIZE && --log2qty);
2849 panic("Failed to allocate %s hash table\n", tablename);
2851 printk("%s hash table entries: %d (order: %d, %lu bytes)\n",
2854 long_log2(size) - PAGE_SHIFT,
2858 *_hash_shift = log2qty;
2860 *_hash_mask = (1 << log2qty) - 1;
2865 #ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
2867 * pfn <-> page translation. out-of-line version.
2868 * (see asm-generic/memory_model.h)
2870 #if defined(CONFIG_FLATMEM)
2871 struct page *pfn_to_page(unsigned long pfn)
2873 return mem_map + (pfn - ARCH_PFN_OFFSET);
2875 unsigned long page_to_pfn(struct page *page)
2877 return (page - mem_map) + ARCH_PFN_OFFSET;
2879 #elif defined(CONFIG_DISCONTIGMEM)
2880 struct page *pfn_to_page(unsigned long pfn)
2882 int nid = arch_pfn_to_nid(pfn);
2883 return NODE_DATA(nid)->node_mem_map + arch_local_page_offset(pfn,nid);
2885 unsigned long page_to_pfn(struct page *page)
2887 struct pglist_data *pgdat = NODE_DATA(page_to_nid(page));
2888 return (page - pgdat->node_mem_map) + pgdat->node_start_pfn;
2890 #elif defined(CONFIG_SPARSEMEM)
2891 struct page *pfn_to_page(unsigned long pfn)
2893 return __section_mem_map_addr(__pfn_to_section(pfn)) + pfn;
2896 unsigned long page_to_pfn(struct page *page)
2898 long section_id = page_to_section(page);
2899 return page - __section_mem_map_addr(__nr_to_section(section_id));
2901 #endif /* CONFIG_FLATMEM/DISCONTIGMME/SPARSEMEM */
2902 EXPORT_SYMBOL(pfn_to_page);
2903 EXPORT_SYMBOL(page_to_pfn);
2904 #endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */