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>
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 totalreserve_pages __read_mostly
;
56 int percpu_pagelist_fraction
;
58 static void __free_pages_ok(struct page
*page
, unsigned int order
);
61 * results with 256, 32 in the lowmem_reserve sysctl:
62 * 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
63 * 1G machine -> (16M dma, 784M normal, 224M high)
64 * NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
65 * HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
66 * HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
68 * TBD: should special case ZONE_DMA32 machines here - in those we normally
69 * don't need any ZONE_NORMAL reservation
71 int sysctl_lowmem_reserve_ratio
[MAX_NR_ZONES
-1] = { 256, 256, 32 };
73 EXPORT_SYMBOL(totalram_pages
);
76 * Used by page_zone() to look up the address of the struct zone whose
77 * id is encoded in the upper bits of page->flags
79 struct zone
*zone_table
[1 << ZONETABLE_SHIFT
] __read_mostly
;
80 EXPORT_SYMBOL(zone_table
);
82 static char *zone_names
[MAX_NR_ZONES
] = { "DMA", "DMA32", "Normal", "HighMem" };
83 int min_free_kbytes
= 1024;
85 unsigned long __meminitdata nr_kernel_pages
;
86 unsigned long __meminitdata nr_all_pages
;
88 #ifdef CONFIG_DEBUG_VM
89 static int page_outside_zone_boundaries(struct zone
*zone
, struct page
*page
)
93 unsigned long pfn
= page_to_pfn(page
);
96 seq
= zone_span_seqbegin(zone
);
97 if (pfn
>= zone
->zone_start_pfn
+ zone
->spanned_pages
)
99 else if (pfn
< zone
->zone_start_pfn
)
101 } while (zone_span_seqretry(zone
, seq
));
106 static int page_is_consistent(struct zone
*zone
, struct page
*page
)
108 #ifdef CONFIG_HOLES_IN_ZONE
109 if (!pfn_valid(page_to_pfn(page
)))
112 if (zone
!= page_zone(page
))
118 * Temporary debugging check for pages not lying within a given zone.
120 static int bad_range(struct zone
*zone
, struct page
*page
)
122 if (page_outside_zone_boundaries(zone
, page
))
124 if (!page_is_consistent(zone
, page
))
130 static inline int bad_range(struct zone
*zone
, struct page
*page
)
136 static void bad_page(struct page
*page
)
138 printk(KERN_EMERG
"Bad page state in process '%s'\n"
139 KERN_EMERG
"page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n"
140 KERN_EMERG
"Trying to fix it up, but a reboot is needed\n"
141 KERN_EMERG
"Backtrace:\n",
142 current
->comm
, page
, (int)(2*sizeof(unsigned long)),
143 (unsigned long)page
->flags
, page
->mapping
,
144 page_mapcount(page
), page_count(page
));
146 page
->flags
&= ~(1 << PG_lru
|
156 set_page_count(page
, 0);
157 reset_page_mapcount(page
);
158 page
->mapping
= NULL
;
159 add_taint(TAINT_BAD_PAGE
);
163 * Higher-order pages are called "compound pages". They are structured thusly:
165 * The first PAGE_SIZE page is called the "head page".
167 * The remaining PAGE_SIZE pages are called "tail pages".
169 * All pages have PG_compound set. All pages have their ->private pointing at
170 * the head page (even the head page has this).
172 * The first tail page's ->lru.next holds the address of the compound page's
173 * put_page() function. Its ->lru.prev holds the order of allocation.
174 * This usage means that zero-order pages may not be compound.
177 static void free_compound_page(struct page
*page
)
179 __free_pages_ok(page
, (unsigned long)page
[1].lru
.prev
);
182 static void prep_compound_page(struct page
*page
, unsigned long order
)
185 int nr_pages
= 1 << order
;
187 page
[1].lru
.next
= (void *)free_compound_page
; /* set dtor */
188 page
[1].lru
.prev
= (void *)order
;
189 for (i
= 0; i
< nr_pages
; i
++) {
190 struct page
*p
= page
+ i
;
192 __SetPageCompound(p
);
193 set_page_private(p
, (unsigned long)page
);
197 static void destroy_compound_page(struct page
*page
, unsigned long order
)
200 int nr_pages
= 1 << order
;
202 if (unlikely((unsigned long)page
[1].lru
.prev
!= order
))
205 for (i
= 0; i
< nr_pages
; i
++) {
206 struct page
*p
= page
+ i
;
208 if (unlikely(!PageCompound(p
) |
209 (page_private(p
) != (unsigned long)page
)))
211 __ClearPageCompound(p
);
215 static inline void prep_zero_page(struct page
*page
, int order
, gfp_t gfp_flags
)
219 VM_BUG_ON((gfp_flags
& (__GFP_WAIT
| __GFP_HIGHMEM
)) == __GFP_HIGHMEM
);
221 * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
222 * and __GFP_HIGHMEM from hard or soft interrupt context.
224 VM_BUG_ON((gfp_flags
& __GFP_HIGHMEM
) && in_interrupt());
225 for (i
= 0; i
< (1 << order
); i
++)
226 clear_highpage(page
+ i
);
230 * function for dealing with page's order in buddy system.
231 * zone->lock is already acquired when we use these.
232 * So, we don't need atomic page->flags operations here.
234 static inline unsigned long page_order(struct page
*page
)
236 return page_private(page
);
239 static inline void set_page_order(struct page
*page
, int order
)
241 set_page_private(page
, order
);
242 __SetPageBuddy(page
);
245 static inline void rmv_page_order(struct page
*page
)
247 __ClearPageBuddy(page
);
248 set_page_private(page
, 0);
252 * Locate the struct page for both the matching buddy in our
253 * pair (buddy1) and the combined O(n+1) page they form (page).
255 * 1) Any buddy B1 will have an order O twin B2 which satisfies
256 * the following equation:
258 * For example, if the starting buddy (buddy2) is #8 its order
260 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
262 * 2) Any buddy B will have an order O+1 parent P which
263 * satisfies the following equation:
266 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
268 static inline struct page
*
269 __page_find_buddy(struct page
*page
, unsigned long page_idx
, unsigned int order
)
271 unsigned long buddy_idx
= page_idx
^ (1 << order
);
273 return page
+ (buddy_idx
- page_idx
);
276 static inline unsigned long
277 __find_combined_index(unsigned long page_idx
, unsigned int order
)
279 return (page_idx
& ~(1 << order
));
283 * This function checks whether a page is free && is the buddy
284 * we can do coalesce a page and its buddy if
285 * (a) the buddy is not in a hole &&
286 * (b) the buddy is in the buddy system &&
287 * (c) a page and its buddy have the same order &&
288 * (d) a page and its buddy are in the same zone.
290 * For recording whether a page is in the buddy system, we use PG_buddy.
291 * Setting, clearing, and testing PG_buddy is serialized by zone->lock.
293 * For recording page's order, we use page_private(page).
295 static inline int page_is_buddy(struct page
*page
, struct page
*buddy
,
298 #ifdef CONFIG_HOLES_IN_ZONE
299 if (!pfn_valid(page_to_pfn(buddy
)))
303 if (page_zone_id(page
) != page_zone_id(buddy
))
306 if (PageBuddy(buddy
) && page_order(buddy
) == order
) {
307 BUG_ON(page_count(buddy
) != 0);
314 * Freeing function for a buddy system allocator.
316 * The concept of a buddy system is to maintain direct-mapped table
317 * (containing bit values) for memory blocks of various "orders".
318 * The bottom level table contains the map for the smallest allocatable
319 * units of memory (here, pages), and each level above it describes
320 * pairs of units from the levels below, hence, "buddies".
321 * At a high level, all that happens here is marking the table entry
322 * at the bottom level available, and propagating the changes upward
323 * as necessary, plus some accounting needed to play nicely with other
324 * parts of the VM system.
325 * At each level, we keep a list of pages, which are heads of continuous
326 * free pages of length of (1 << order) and marked with PG_buddy. Page's
327 * order is recorded in page_private(page) field.
328 * So when we are allocating or freeing one, we can derive the state of the
329 * other. That is, if we allocate a small block, and both were
330 * free, the remainder of the region must be split into blocks.
331 * If a block is freed, and its buddy is also free, then this
332 * triggers coalescing into a block of larger size.
337 static inline void __free_one_page(struct page
*page
,
338 struct zone
*zone
, unsigned int order
)
340 unsigned long page_idx
;
341 int order_size
= 1 << order
;
343 if (unlikely(PageCompound(page
)))
344 destroy_compound_page(page
, order
);
346 page_idx
= page_to_pfn(page
) & ((1 << MAX_ORDER
) - 1);
348 VM_BUG_ON(page_idx
& (order_size
- 1));
349 VM_BUG_ON(bad_range(zone
, page
));
351 zone
->free_pages
+= order_size
;
352 while (order
< MAX_ORDER
-1) {
353 unsigned long combined_idx
;
354 struct free_area
*area
;
357 buddy
= __page_find_buddy(page
, page_idx
, order
);
358 if (!page_is_buddy(page
, buddy
, order
))
359 break; /* Move the buddy up one level. */
361 list_del(&buddy
->lru
);
362 area
= zone
->free_area
+ order
;
364 rmv_page_order(buddy
);
365 combined_idx
= __find_combined_index(page_idx
, order
);
366 page
= page
+ (combined_idx
- page_idx
);
367 page_idx
= combined_idx
;
370 set_page_order(page
, order
);
371 list_add(&page
->lru
, &zone
->free_area
[order
].free_list
);
372 zone
->free_area
[order
].nr_free
++;
375 static inline int free_pages_check(struct page
*page
)
377 if (unlikely(page_mapcount(page
) |
378 (page
->mapping
!= NULL
) |
379 (page_count(page
) != 0) |
393 __ClearPageDirty(page
);
395 * For now, we report if PG_reserved was found set, but do not
396 * clear it, and do not free the page. But we shall soon need
397 * to do more, for when the ZERO_PAGE count wraps negative.
399 return PageReserved(page
);
403 * Frees a list of pages.
404 * Assumes all pages on list are in same zone, and of same order.
405 * count is the number of pages to free.
407 * If the zone was previously in an "all pages pinned" state then look to
408 * see if this freeing clears that state.
410 * And clear the zone's pages_scanned counter, to hold off the "all pages are
411 * pinned" detection logic.
413 static void free_pages_bulk(struct zone
*zone
, int count
,
414 struct list_head
*list
, int order
)
416 spin_lock(&zone
->lock
);
417 zone
->all_unreclaimable
= 0;
418 zone
->pages_scanned
= 0;
422 VM_BUG_ON(list_empty(list
));
423 page
= list_entry(list
->prev
, struct page
, lru
);
424 /* have to delete it as __free_one_page list manipulates */
425 list_del(&page
->lru
);
426 __free_one_page(page
, zone
, order
);
428 spin_unlock(&zone
->lock
);
431 static void free_one_page(struct zone
*zone
, struct page
*page
, int order
)
434 list_add(&page
->lru
, &list
);
435 free_pages_bulk(zone
, 1, &list
, order
);
438 static void __free_pages_ok(struct page
*page
, unsigned int order
)
444 arch_free_page(page
, order
);
445 if (!PageHighMem(page
))
446 debug_check_no_locks_freed(page_address(page
),
449 for (i
= 0 ; i
< (1 << order
) ; ++i
)
450 reserved
+= free_pages_check(page
+ i
);
454 kernel_map_pages(page
, 1 << order
, 0);
455 local_irq_save(flags
);
456 __count_vm_events(PGFREE
, 1 << order
);
457 free_one_page(page_zone(page
), page
, order
);
458 local_irq_restore(flags
);
462 * permit the bootmem allocator to evade page validation on high-order frees
464 void fastcall __init
__free_pages_bootmem(struct page
*page
, unsigned int order
)
467 __ClearPageReserved(page
);
468 set_page_count(page
, 0);
469 set_page_refcounted(page
);
475 for (loop
= 0; loop
< BITS_PER_LONG
; loop
++) {
476 struct page
*p
= &page
[loop
];
478 if (loop
+ 1 < BITS_PER_LONG
)
480 __ClearPageReserved(p
);
481 set_page_count(p
, 0);
484 set_page_refcounted(page
);
485 __free_pages(page
, order
);
491 * The order of subdivision here is critical for the IO subsystem.
492 * Please do not alter this order without good reasons and regression
493 * testing. Specifically, as large blocks of memory are subdivided,
494 * the order in which smaller blocks are delivered depends on the order
495 * they're subdivided in this function. This is the primary factor
496 * influencing the order in which pages are delivered to the IO
497 * subsystem according to empirical testing, and this is also justified
498 * by considering the behavior of a buddy system containing a single
499 * large block of memory acted on by a series of small allocations.
500 * This behavior is a critical factor in sglist merging's success.
504 static inline void expand(struct zone
*zone
, struct page
*page
,
505 int low
, int high
, struct free_area
*area
)
507 unsigned long size
= 1 << high
;
513 VM_BUG_ON(bad_range(zone
, &page
[size
]));
514 list_add(&page
[size
].lru
, &area
->free_list
);
516 set_page_order(&page
[size
], high
);
521 * This page is about to be returned from the page allocator
523 static int prep_new_page(struct page
*page
, int order
, gfp_t gfp_flags
)
525 if (unlikely(page_mapcount(page
) |
526 (page
->mapping
!= NULL
) |
527 (page_count(page
) != 0) |
543 * For now, we report if PG_reserved was found set, but do not
544 * clear it, and do not allocate the page: as a safety net.
546 if (PageReserved(page
))
549 page
->flags
&= ~(1 << PG_uptodate
| 1 << PG_error
|
550 1 << PG_referenced
| 1 << PG_arch_1
|
551 1 << PG_checked
| 1 << PG_mappedtodisk
);
552 set_page_private(page
, 0);
553 set_page_refcounted(page
);
554 kernel_map_pages(page
, 1 << order
, 1);
556 if (gfp_flags
& __GFP_ZERO
)
557 prep_zero_page(page
, order
, gfp_flags
);
559 if (order
&& (gfp_flags
& __GFP_COMP
))
560 prep_compound_page(page
, order
);
566 * Do the hard work of removing an element from the buddy allocator.
567 * Call me with the zone->lock already held.
569 static struct page
*__rmqueue(struct zone
*zone
, unsigned int order
)
571 struct free_area
* area
;
572 unsigned int current_order
;
575 for (current_order
= order
; current_order
< MAX_ORDER
; ++current_order
) {
576 area
= zone
->free_area
+ current_order
;
577 if (list_empty(&area
->free_list
))
580 page
= list_entry(area
->free_list
.next
, struct page
, lru
);
581 list_del(&page
->lru
);
582 rmv_page_order(page
);
584 zone
->free_pages
-= 1UL << order
;
585 expand(zone
, page
, order
, current_order
, area
);
593 * Obtain a specified number of elements from the buddy allocator, all under
594 * a single hold of the lock, for efficiency. Add them to the supplied list.
595 * Returns the number of new pages which were placed at *list.
597 static int rmqueue_bulk(struct zone
*zone
, unsigned int order
,
598 unsigned long count
, struct list_head
*list
)
602 spin_lock(&zone
->lock
);
603 for (i
= 0; i
< count
; ++i
) {
604 struct page
*page
= __rmqueue(zone
, order
);
605 if (unlikely(page
== NULL
))
607 list_add_tail(&page
->lru
, list
);
609 spin_unlock(&zone
->lock
);
615 * Called from the slab reaper to drain pagesets on a particular node that
616 * belong to the currently executing processor.
617 * Note that this function must be called with the thread pinned to
618 * a single processor.
620 void drain_node_pages(int nodeid
)
625 for (z
= 0; z
< MAX_NR_ZONES
; z
++) {
626 struct zone
*zone
= NODE_DATA(nodeid
)->node_zones
+ z
;
627 struct per_cpu_pageset
*pset
;
629 pset
= zone_pcp(zone
, smp_processor_id());
630 for (i
= 0; i
< ARRAY_SIZE(pset
->pcp
); i
++) {
631 struct per_cpu_pages
*pcp
;
635 local_irq_save(flags
);
636 free_pages_bulk(zone
, pcp
->count
, &pcp
->list
, 0);
638 local_irq_restore(flags
);
645 #if defined(CONFIG_PM) || defined(CONFIG_HOTPLUG_CPU)
646 static void __drain_pages(unsigned int cpu
)
652 for_each_zone(zone
) {
653 struct per_cpu_pageset
*pset
;
655 pset
= zone_pcp(zone
, cpu
);
656 for (i
= 0; i
< ARRAY_SIZE(pset
->pcp
); i
++) {
657 struct per_cpu_pages
*pcp
;
660 local_irq_save(flags
);
661 free_pages_bulk(zone
, pcp
->count
, &pcp
->list
, 0);
663 local_irq_restore(flags
);
667 #endif /* CONFIG_PM || CONFIG_HOTPLUG_CPU */
671 void mark_free_pages(struct zone
*zone
)
673 unsigned long zone_pfn
, flags
;
675 struct list_head
*curr
;
677 if (!zone
->spanned_pages
)
680 spin_lock_irqsave(&zone
->lock
, flags
);
681 for (zone_pfn
= 0; zone_pfn
< zone
->spanned_pages
; ++zone_pfn
)
682 ClearPageNosaveFree(pfn_to_page(zone_pfn
+ zone
->zone_start_pfn
));
684 for (order
= MAX_ORDER
- 1; order
>= 0; --order
)
685 list_for_each(curr
, &zone
->free_area
[order
].free_list
) {
686 unsigned long start_pfn
, i
;
688 start_pfn
= page_to_pfn(list_entry(curr
, struct page
, lru
));
690 for (i
=0; i
< (1<<order
); i
++)
691 SetPageNosaveFree(pfn_to_page(start_pfn
+i
));
693 spin_unlock_irqrestore(&zone
->lock
, flags
);
697 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
699 void drain_local_pages(void)
703 local_irq_save(flags
);
704 __drain_pages(smp_processor_id());
705 local_irq_restore(flags
);
707 #endif /* CONFIG_PM */
710 * Free a 0-order page
712 static void fastcall
free_hot_cold_page(struct page
*page
, int cold
)
714 struct zone
*zone
= page_zone(page
);
715 struct per_cpu_pages
*pcp
;
718 arch_free_page(page
, 0);
721 page
->mapping
= NULL
;
722 if (free_pages_check(page
))
725 kernel_map_pages(page
, 1, 0);
727 pcp
= &zone_pcp(zone
, get_cpu())->pcp
[cold
];
728 local_irq_save(flags
);
729 __count_vm_event(PGFREE
);
730 list_add(&page
->lru
, &pcp
->list
);
732 if (pcp
->count
>= pcp
->high
) {
733 free_pages_bulk(zone
, pcp
->batch
, &pcp
->list
, 0);
734 pcp
->count
-= pcp
->batch
;
736 local_irq_restore(flags
);
740 void fastcall
free_hot_page(struct page
*page
)
742 free_hot_cold_page(page
, 0);
745 void fastcall
free_cold_page(struct page
*page
)
747 free_hot_cold_page(page
, 1);
751 * split_page takes a non-compound higher-order page, and splits it into
752 * n (1<<order) sub-pages: page[0..n]
753 * Each sub-page must be freed individually.
755 * Note: this is probably too low level an operation for use in drivers.
756 * Please consult with lkml before using this in your driver.
758 void split_page(struct page
*page
, unsigned int order
)
762 VM_BUG_ON(PageCompound(page
));
763 VM_BUG_ON(!page_count(page
));
764 for (i
= 1; i
< (1 << order
); i
++)
765 set_page_refcounted(page
+ i
);
769 * Really, prep_compound_page() should be called from __rmqueue_bulk(). But
770 * we cheat by calling it from here, in the order > 0 path. Saves a branch
773 static struct page
*buffered_rmqueue(struct zonelist
*zonelist
,
774 struct zone
*zone
, int order
, gfp_t gfp_flags
)
778 int cold
= !!(gfp_flags
& __GFP_COLD
);
783 if (likely(order
== 0)) {
784 struct per_cpu_pages
*pcp
;
786 pcp
= &zone_pcp(zone
, cpu
)->pcp
[cold
];
787 local_irq_save(flags
);
789 pcp
->count
+= rmqueue_bulk(zone
, 0,
790 pcp
->batch
, &pcp
->list
);
791 if (unlikely(!pcp
->count
))
794 page
= list_entry(pcp
->list
.next
, struct page
, lru
);
795 list_del(&page
->lru
);
798 spin_lock_irqsave(&zone
->lock
, flags
);
799 page
= __rmqueue(zone
, order
);
800 spin_unlock(&zone
->lock
);
805 __count_zone_vm_events(PGALLOC
, zone
, 1 << order
);
806 zone_statistics(zonelist
, zone
);
807 local_irq_restore(flags
);
810 VM_BUG_ON(bad_range(zone
, page
));
811 if (prep_new_page(page
, order
, gfp_flags
))
816 local_irq_restore(flags
);
821 #define ALLOC_NO_WATERMARKS 0x01 /* don't check watermarks at all */
822 #define ALLOC_WMARK_MIN 0x02 /* use pages_min watermark */
823 #define ALLOC_WMARK_LOW 0x04 /* use pages_low watermark */
824 #define ALLOC_WMARK_HIGH 0x08 /* use pages_high watermark */
825 #define ALLOC_HARDER 0x10 /* try to alloc harder */
826 #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
827 #define ALLOC_CPUSET 0x40 /* check for correct cpuset */
830 * Return 1 if free pages are above 'mark'. This takes into account the order
833 int zone_watermark_ok(struct zone
*z
, int order
, unsigned long mark
,
834 int classzone_idx
, int alloc_flags
)
836 /* free_pages my go negative - that's OK */
837 long min
= mark
, free_pages
= z
->free_pages
- (1 << order
) + 1;
840 if (alloc_flags
& ALLOC_HIGH
)
842 if (alloc_flags
& ALLOC_HARDER
)
845 if (free_pages
<= min
+ z
->lowmem_reserve
[classzone_idx
])
847 for (o
= 0; o
< order
; o
++) {
848 /* At the next order, this order's pages become unavailable */
849 free_pages
-= z
->free_area
[o
].nr_free
<< o
;
851 /* Require fewer higher order pages to be free */
854 if (free_pages
<= min
)
861 * get_page_from_freeliest goes through the zonelist trying to allocate
865 get_page_from_freelist(gfp_t gfp_mask
, unsigned int order
,
866 struct zonelist
*zonelist
, int alloc_flags
)
868 struct zone
**z
= zonelist
->zones
;
869 struct page
*page
= NULL
;
870 int classzone_idx
= zone_idx(*z
);
873 * Go through the zonelist once, looking for a zone with enough free.
874 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
877 if ((alloc_flags
& ALLOC_CPUSET
) &&
878 !cpuset_zone_allowed(*z
, gfp_mask
))
881 if (!(alloc_flags
& ALLOC_NO_WATERMARKS
)) {
883 if (alloc_flags
& ALLOC_WMARK_MIN
)
884 mark
= (*z
)->pages_min
;
885 else if (alloc_flags
& ALLOC_WMARK_LOW
)
886 mark
= (*z
)->pages_low
;
888 mark
= (*z
)->pages_high
;
889 if (!zone_watermark_ok(*z
, order
, mark
,
890 classzone_idx
, alloc_flags
))
891 if (!zone_reclaim_mode
||
892 !zone_reclaim(*z
, gfp_mask
, order
))
896 page
= buffered_rmqueue(zonelist
, *z
, order
, gfp_mask
);
900 } while (*(++z
) != NULL
);
905 * This is the 'heart' of the zoned buddy allocator.
907 struct page
* fastcall
908 __alloc_pages(gfp_t gfp_mask
, unsigned int order
,
909 struct zonelist
*zonelist
)
911 const gfp_t wait
= gfp_mask
& __GFP_WAIT
;
914 struct reclaim_state reclaim_state
;
915 struct task_struct
*p
= current
;
918 int did_some_progress
;
920 might_sleep_if(wait
);
923 z
= zonelist
->zones
; /* the list of zones suitable for gfp_mask */
925 if (unlikely(*z
== NULL
)) {
926 /* Should this ever happen?? */
930 page
= get_page_from_freelist(gfp_mask
|__GFP_HARDWALL
, order
,
931 zonelist
, ALLOC_WMARK_LOW
|ALLOC_CPUSET
);
936 wakeup_kswapd(*z
, order
);
940 * OK, we're below the kswapd watermark and have kicked background
941 * reclaim. Now things get more complex, so set up alloc_flags according
942 * to how we want to proceed.
944 * The caller may dip into page reserves a bit more if the caller
945 * cannot run direct reclaim, or if the caller has realtime scheduling
946 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
947 * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
949 alloc_flags
= ALLOC_WMARK_MIN
;
950 if ((unlikely(rt_task(p
)) && !in_interrupt()) || !wait
)
951 alloc_flags
|= ALLOC_HARDER
;
952 if (gfp_mask
& __GFP_HIGH
)
953 alloc_flags
|= ALLOC_HIGH
;
955 alloc_flags
|= ALLOC_CPUSET
;
958 * Go through the zonelist again. Let __GFP_HIGH and allocations
959 * coming from realtime tasks go deeper into reserves.
961 * This is the last chance, in general, before the goto nopage.
962 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
963 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
965 page
= get_page_from_freelist(gfp_mask
, order
, zonelist
, alloc_flags
);
969 /* This allocation should allow future memory freeing. */
971 if (((p
->flags
& PF_MEMALLOC
) || unlikely(test_thread_flag(TIF_MEMDIE
)))
972 && !in_interrupt()) {
973 if (!(gfp_mask
& __GFP_NOMEMALLOC
)) {
975 /* go through the zonelist yet again, ignoring mins */
976 page
= get_page_from_freelist(gfp_mask
, order
,
977 zonelist
, ALLOC_NO_WATERMARKS
);
980 if (gfp_mask
& __GFP_NOFAIL
) {
981 blk_congestion_wait(WRITE
, HZ
/50);
988 /* Atomic allocations - we can't balance anything */
995 /* We now go into synchronous reclaim */
996 cpuset_memory_pressure_bump();
997 p
->flags
|= PF_MEMALLOC
;
998 reclaim_state
.reclaimed_slab
= 0;
999 p
->reclaim_state
= &reclaim_state
;
1001 did_some_progress
= try_to_free_pages(zonelist
->zones
, gfp_mask
);
1003 p
->reclaim_state
= NULL
;
1004 p
->flags
&= ~PF_MEMALLOC
;
1008 if (likely(did_some_progress
)) {
1009 page
= get_page_from_freelist(gfp_mask
, order
,
1010 zonelist
, alloc_flags
);
1013 } else if ((gfp_mask
& __GFP_FS
) && !(gfp_mask
& __GFP_NORETRY
)) {
1015 * Go through the zonelist yet one more time, keep
1016 * very high watermark here, this is only to catch
1017 * a parallel oom killing, we must fail if we're still
1018 * under heavy pressure.
1020 page
= get_page_from_freelist(gfp_mask
|__GFP_HARDWALL
, order
,
1021 zonelist
, ALLOC_WMARK_HIGH
|ALLOC_CPUSET
);
1025 out_of_memory(zonelist
, gfp_mask
, order
);
1030 * Don't let big-order allocations loop unless the caller explicitly
1031 * requests that. Wait for some write requests to complete then retry.
1033 * In this implementation, __GFP_REPEAT means __GFP_NOFAIL for order
1034 * <= 3, but that may not be true in other implementations.
1037 if (!(gfp_mask
& __GFP_NORETRY
)) {
1038 if ((order
<= 3) || (gfp_mask
& __GFP_REPEAT
))
1040 if (gfp_mask
& __GFP_NOFAIL
)
1044 blk_congestion_wait(WRITE
, HZ
/50);
1049 if (!(gfp_mask
& __GFP_NOWARN
) && printk_ratelimit()) {
1050 printk(KERN_WARNING
"%s: page allocation failure."
1051 " order:%d, mode:0x%x\n",
1052 p
->comm
, order
, gfp_mask
);
1060 EXPORT_SYMBOL(__alloc_pages
);
1063 * Common helper functions.
1065 fastcall
unsigned long __get_free_pages(gfp_t gfp_mask
, unsigned int order
)
1068 page
= alloc_pages(gfp_mask
, order
);
1071 return (unsigned long) page_address(page
);
1074 EXPORT_SYMBOL(__get_free_pages
);
1076 fastcall
unsigned long get_zeroed_page(gfp_t gfp_mask
)
1081 * get_zeroed_page() returns a 32-bit address, which cannot represent
1084 VM_BUG_ON((gfp_mask
& __GFP_HIGHMEM
) != 0);
1086 page
= alloc_pages(gfp_mask
| __GFP_ZERO
, 0);
1088 return (unsigned long) page_address(page
);
1092 EXPORT_SYMBOL(get_zeroed_page
);
1094 void __pagevec_free(struct pagevec
*pvec
)
1096 int i
= pagevec_count(pvec
);
1099 free_hot_cold_page(pvec
->pages
[i
], pvec
->cold
);
1102 fastcall
void __free_pages(struct page
*page
, unsigned int order
)
1104 if (put_page_testzero(page
)) {
1106 free_hot_page(page
);
1108 __free_pages_ok(page
, order
);
1112 EXPORT_SYMBOL(__free_pages
);
1114 fastcall
void free_pages(unsigned long addr
, unsigned int order
)
1117 VM_BUG_ON(!virt_addr_valid((void *)addr
));
1118 __free_pages(virt_to_page((void *)addr
), order
);
1122 EXPORT_SYMBOL(free_pages
);
1125 * Total amount of free (allocatable) RAM:
1127 unsigned int nr_free_pages(void)
1129 unsigned int sum
= 0;
1133 sum
+= zone
->free_pages
;
1138 EXPORT_SYMBOL(nr_free_pages
);
1141 unsigned int nr_free_pages_pgdat(pg_data_t
*pgdat
)
1143 unsigned int i
, sum
= 0;
1145 for (i
= 0; i
< MAX_NR_ZONES
; i
++)
1146 sum
+= pgdat
->node_zones
[i
].free_pages
;
1152 static unsigned int nr_free_zone_pages(int offset
)
1154 /* Just pick one node, since fallback list is circular */
1155 pg_data_t
*pgdat
= NODE_DATA(numa_node_id());
1156 unsigned int sum
= 0;
1158 struct zonelist
*zonelist
= pgdat
->node_zonelists
+ offset
;
1159 struct zone
**zonep
= zonelist
->zones
;
1162 for (zone
= *zonep
++; zone
; zone
= *zonep
++) {
1163 unsigned long size
= zone
->present_pages
;
1164 unsigned long high
= zone
->pages_high
;
1173 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
1175 unsigned int nr_free_buffer_pages(void)
1177 return nr_free_zone_pages(gfp_zone(GFP_USER
));
1181 * Amount of free RAM allocatable within all zones
1183 unsigned int nr_free_pagecache_pages(void)
1185 return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER
));
1188 static void show_node(struct zone
*zone
)
1190 printk("Node %d ", zone
->zone_pgdat
->node_id
);
1193 #define show_node(zone) do { } while (0)
1196 void si_meminfo(struct sysinfo
*val
)
1198 val
->totalram
= totalram_pages
;
1200 val
->freeram
= nr_free_pages();
1201 val
->bufferram
= nr_blockdev_pages();
1202 #ifdef CONFIG_HIGHMEM
1203 val
->totalhigh
= totalhigh_pages
;
1204 val
->freehigh
= nr_free_highpages();
1209 val
->mem_unit
= PAGE_SIZE
;
1212 EXPORT_SYMBOL(si_meminfo
);
1215 void si_meminfo_node(struct sysinfo
*val
, int nid
)
1217 pg_data_t
*pgdat
= NODE_DATA(nid
);
1219 val
->totalram
= pgdat
->node_present_pages
;
1220 val
->freeram
= nr_free_pages_pgdat(pgdat
);
1221 val
->totalhigh
= pgdat
->node_zones
[ZONE_HIGHMEM
].present_pages
;
1222 val
->freehigh
= pgdat
->node_zones
[ZONE_HIGHMEM
].free_pages
;
1223 val
->mem_unit
= PAGE_SIZE
;
1227 #define K(x) ((x) << (PAGE_SHIFT-10))
1230 * Show free area list (used inside shift_scroll-lock stuff)
1231 * We also calculate the percentage fragmentation. We do this by counting the
1232 * memory on each free list with the exception of the first item on the list.
1234 void show_free_areas(void)
1236 int cpu
, temperature
;
1237 unsigned long active
;
1238 unsigned long inactive
;
1242 for_each_zone(zone
) {
1244 printk("%s per-cpu:", zone
->name
);
1246 if (!populated_zone(zone
)) {
1252 for_each_online_cpu(cpu
) {
1253 struct per_cpu_pageset
*pageset
;
1255 pageset
= zone_pcp(zone
, cpu
);
1257 for (temperature
= 0; temperature
< 2; temperature
++)
1258 printk("cpu %d %s: high %d, batch %d used:%d\n",
1260 temperature
? "cold" : "hot",
1261 pageset
->pcp
[temperature
].high
,
1262 pageset
->pcp
[temperature
].batch
,
1263 pageset
->pcp
[temperature
].count
);
1267 get_zone_counts(&active
, &inactive
, &free
);
1269 printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu "
1270 "unstable:%lu free:%u slab:%lu mapped:%lu pagetables:%lu\n",
1273 global_page_state(NR_FILE_DIRTY
),
1274 global_page_state(NR_WRITEBACK
),
1275 global_page_state(NR_UNSTABLE_NFS
),
1277 global_page_state(NR_SLAB
),
1278 global_page_state(NR_FILE_MAPPED
),
1279 global_page_state(NR_PAGETABLE
));
1281 for_each_zone(zone
) {
1293 " pages_scanned:%lu"
1294 " all_unreclaimable? %s"
1297 K(zone
->free_pages
),
1300 K(zone
->pages_high
),
1302 K(zone
->nr_inactive
),
1303 K(zone
->present_pages
),
1304 zone
->pages_scanned
,
1305 (zone
->all_unreclaimable
? "yes" : "no")
1307 printk("lowmem_reserve[]:");
1308 for (i
= 0; i
< MAX_NR_ZONES
; i
++)
1309 printk(" %lu", zone
->lowmem_reserve
[i
]);
1313 for_each_zone(zone
) {
1314 unsigned long nr
[MAX_ORDER
], flags
, order
, total
= 0;
1317 printk("%s: ", zone
->name
);
1318 if (!populated_zone(zone
)) {
1323 spin_lock_irqsave(&zone
->lock
, flags
);
1324 for (order
= 0; order
< MAX_ORDER
; order
++) {
1325 nr
[order
] = zone
->free_area
[order
].nr_free
;
1326 total
+= nr
[order
] << order
;
1328 spin_unlock_irqrestore(&zone
->lock
, flags
);
1329 for (order
= 0; order
< MAX_ORDER
; order
++)
1330 printk("%lu*%lukB ", nr
[order
], K(1UL) << order
);
1331 printk("= %lukB\n", K(total
));
1334 show_swap_cache_info();
1338 * Builds allocation fallback zone lists.
1340 * Add all populated zones of a node to the zonelist.
1342 static int __meminit
build_zonelists_node(pg_data_t
*pgdat
,
1343 struct zonelist
*zonelist
, int nr_zones
, int zone_type
)
1347 BUG_ON(zone_type
> ZONE_HIGHMEM
);
1350 zone
= pgdat
->node_zones
+ zone_type
;
1351 if (populated_zone(zone
)) {
1352 #ifndef CONFIG_HIGHMEM
1353 BUG_ON(zone_type
> ZONE_NORMAL
);
1355 zonelist
->zones
[nr_zones
++] = zone
;
1356 check_highest_zone(zone_type
);
1360 } while (zone_type
>= 0);
1364 static inline int highest_zone(int zone_bits
)
1366 int res
= ZONE_NORMAL
;
1367 if (zone_bits
& (__force
int)__GFP_HIGHMEM
)
1369 if (zone_bits
& (__force
int)__GFP_DMA32
)
1371 if (zone_bits
& (__force
int)__GFP_DMA
)
1377 #define MAX_NODE_LOAD (num_online_nodes())
1378 static int __meminitdata node_load
[MAX_NUMNODES
];
1380 * find_next_best_node - find the next node that should appear in a given node's fallback list
1381 * @node: node whose fallback list we're appending
1382 * @used_node_mask: nodemask_t of already used nodes
1384 * We use a number of factors to determine which is the next node that should
1385 * appear on a given node's fallback list. The node should not have appeared
1386 * already in @node's fallback list, and it should be the next closest node
1387 * according to the distance array (which contains arbitrary distance values
1388 * from each node to each node in the system), and should also prefer nodes
1389 * with no CPUs, since presumably they'll have very little allocation pressure
1390 * on them otherwise.
1391 * It returns -1 if no node is found.
1393 static int __meminit
find_next_best_node(int node
, nodemask_t
*used_node_mask
)
1396 int min_val
= INT_MAX
;
1399 /* Use the local node if we haven't already */
1400 if (!node_isset(node
, *used_node_mask
)) {
1401 node_set(node
, *used_node_mask
);
1405 for_each_online_node(n
) {
1408 /* Don't want a node to appear more than once */
1409 if (node_isset(n
, *used_node_mask
))
1412 /* Use the distance array to find the distance */
1413 val
= node_distance(node
, n
);
1415 /* Penalize nodes under us ("prefer the next node") */
1418 /* Give preference to headless and unused nodes */
1419 tmp
= node_to_cpumask(n
);
1420 if (!cpus_empty(tmp
))
1421 val
+= PENALTY_FOR_NODE_WITH_CPUS
;
1423 /* Slight preference for less loaded node */
1424 val
*= (MAX_NODE_LOAD
*MAX_NUMNODES
);
1425 val
+= node_load
[n
];
1427 if (val
< min_val
) {
1434 node_set(best_node
, *used_node_mask
);
1439 static void __meminit
build_zonelists(pg_data_t
*pgdat
)
1441 int i
, j
, k
, node
, local_node
;
1442 int prev_node
, load
;
1443 struct zonelist
*zonelist
;
1444 nodemask_t used_mask
;
1446 /* initialize zonelists */
1447 for (i
= 0; i
< GFP_ZONETYPES
; i
++) {
1448 zonelist
= pgdat
->node_zonelists
+ i
;
1449 zonelist
->zones
[0] = NULL
;
1452 /* NUMA-aware ordering of nodes */
1453 local_node
= pgdat
->node_id
;
1454 load
= num_online_nodes();
1455 prev_node
= local_node
;
1456 nodes_clear(used_mask
);
1457 while ((node
= find_next_best_node(local_node
, &used_mask
)) >= 0) {
1458 int distance
= node_distance(local_node
, node
);
1461 * If another node is sufficiently far away then it is better
1462 * to reclaim pages in a zone before going off node.
1464 if (distance
> RECLAIM_DISTANCE
)
1465 zone_reclaim_mode
= 1;
1468 * We don't want to pressure a particular node.
1469 * So adding penalty to the first node in same
1470 * distance group to make it round-robin.
1473 if (distance
!= node_distance(local_node
, prev_node
))
1474 node_load
[node
] += load
;
1477 for (i
= 0; i
< GFP_ZONETYPES
; i
++) {
1478 zonelist
= pgdat
->node_zonelists
+ i
;
1479 for (j
= 0; zonelist
->zones
[j
] != NULL
; j
++);
1481 k
= highest_zone(i
);
1483 j
= build_zonelists_node(NODE_DATA(node
), zonelist
, j
, k
);
1484 zonelist
->zones
[j
] = NULL
;
1489 #else /* CONFIG_NUMA */
1491 static void __meminit
build_zonelists(pg_data_t
*pgdat
)
1493 int i
, j
, k
, node
, local_node
;
1495 local_node
= pgdat
->node_id
;
1496 for (i
= 0; i
< GFP_ZONETYPES
; i
++) {
1497 struct zonelist
*zonelist
;
1499 zonelist
= pgdat
->node_zonelists
+ i
;
1502 k
= highest_zone(i
);
1503 j
= build_zonelists_node(pgdat
, zonelist
, j
, k
);
1505 * Now we build the zonelist so that it contains the zones
1506 * of all the other nodes.
1507 * We don't want to pressure a particular node, so when
1508 * building the zones for node N, we make sure that the
1509 * zones coming right after the local ones are those from
1510 * node N+1 (modulo N)
1512 for (node
= local_node
+ 1; node
< MAX_NUMNODES
; node
++) {
1513 if (!node_online(node
))
1515 j
= build_zonelists_node(NODE_DATA(node
), zonelist
, j
, k
);
1517 for (node
= 0; node
< local_node
; node
++) {
1518 if (!node_online(node
))
1520 j
= build_zonelists_node(NODE_DATA(node
), zonelist
, j
, k
);
1523 zonelist
->zones
[j
] = NULL
;
1527 #endif /* CONFIG_NUMA */
1529 /* return values int ....just for stop_machine_run() */
1530 static int __meminit
__build_all_zonelists(void *dummy
)
1533 for_each_online_node(nid
)
1534 build_zonelists(NODE_DATA(nid
));
1538 void __meminit
build_all_zonelists(void)
1540 if (system_state
== SYSTEM_BOOTING
) {
1541 __build_all_zonelists(0);
1542 cpuset_init_current_mems_allowed();
1544 /* we have to stop all cpus to guaranntee there is no user
1546 stop_machine_run(__build_all_zonelists
, NULL
, NR_CPUS
);
1547 /* cpuset refresh routine should be here */
1549 vm_total_pages
= nr_free_pagecache_pages();
1550 printk("Built %i zonelists. Total pages: %ld\n",
1551 num_online_nodes(), vm_total_pages
);
1555 * Helper functions to size the waitqueue hash table.
1556 * Essentially these want to choose hash table sizes sufficiently
1557 * large so that collisions trying to wait on pages are rare.
1558 * But in fact, the number of active page waitqueues on typical
1559 * systems is ridiculously low, less than 200. So this is even
1560 * conservative, even though it seems large.
1562 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
1563 * waitqueues, i.e. the size of the waitq table given the number of pages.
1565 #define PAGES_PER_WAITQUEUE 256
1567 #ifndef CONFIG_MEMORY_HOTPLUG
1568 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages
)
1570 unsigned long size
= 1;
1572 pages
/= PAGES_PER_WAITQUEUE
;
1574 while (size
< pages
)
1578 * Once we have dozens or even hundreds of threads sleeping
1579 * on IO we've got bigger problems than wait queue collision.
1580 * Limit the size of the wait table to a reasonable size.
1582 size
= min(size
, 4096UL);
1584 return max(size
, 4UL);
1588 * A zone's size might be changed by hot-add, so it is not possible to determine
1589 * a suitable size for its wait_table. So we use the maximum size now.
1591 * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie:
1593 * i386 (preemption config) : 4096 x 16 = 64Kbyte.
1594 * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
1595 * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte.
1597 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
1598 * or more by the traditional way. (See above). It equals:
1600 * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte.
1601 * ia64(16K page size) : = ( 8G + 4M)byte.
1602 * powerpc (64K page size) : = (32G +16M)byte.
1604 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages
)
1611 * This is an integer logarithm so that shifts can be used later
1612 * to extract the more random high bits from the multiplicative
1613 * hash function before the remainder is taken.
1615 static inline unsigned long wait_table_bits(unsigned long size
)
1620 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
1622 static void __init
calculate_zone_totalpages(struct pglist_data
*pgdat
,
1623 unsigned long *zones_size
, unsigned long *zholes_size
)
1625 unsigned long realtotalpages
, totalpages
= 0;
1628 for (i
= 0; i
< MAX_NR_ZONES
; i
++)
1629 totalpages
+= zones_size
[i
];
1630 pgdat
->node_spanned_pages
= totalpages
;
1632 realtotalpages
= totalpages
;
1634 for (i
= 0; i
< MAX_NR_ZONES
; i
++)
1635 realtotalpages
-= zholes_size
[i
];
1636 pgdat
->node_present_pages
= realtotalpages
;
1637 printk(KERN_DEBUG
"On node %d totalpages: %lu\n", pgdat
->node_id
, realtotalpages
);
1642 * Initially all pages are reserved - free ones are freed
1643 * up by free_all_bootmem() once the early boot process is
1644 * done. Non-atomic initialization, single-pass.
1646 void __meminit
memmap_init_zone(unsigned long size
, int nid
, unsigned long zone
,
1647 unsigned long start_pfn
)
1650 unsigned long end_pfn
= start_pfn
+ size
;
1653 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
++) {
1654 if (!early_pfn_valid(pfn
))
1656 page
= pfn_to_page(pfn
);
1657 set_page_links(page
, zone
, nid
, pfn
);
1658 init_page_count(page
);
1659 reset_page_mapcount(page
);
1660 SetPageReserved(page
);
1661 INIT_LIST_HEAD(&page
->lru
);
1662 #ifdef WANT_PAGE_VIRTUAL
1663 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
1664 if (!is_highmem_idx(zone
))
1665 set_page_address(page
, __va(pfn
<< PAGE_SHIFT
));
1670 void zone_init_free_lists(struct pglist_data
*pgdat
, struct zone
*zone
,
1674 for (order
= 0; order
< MAX_ORDER
; order
++) {
1675 INIT_LIST_HEAD(&zone
->free_area
[order
].free_list
);
1676 zone
->free_area
[order
].nr_free
= 0;
1680 #define ZONETABLE_INDEX(x, zone_nr) ((x << ZONES_SHIFT) | zone_nr)
1681 void zonetable_add(struct zone
*zone
, int nid
, int zid
, unsigned long pfn
,
1684 unsigned long snum
= pfn_to_section_nr(pfn
);
1685 unsigned long end
= pfn_to_section_nr(pfn
+ size
);
1688 zone_table
[ZONETABLE_INDEX(nid
, zid
)] = zone
;
1690 for (; snum
<= end
; snum
++)
1691 zone_table
[ZONETABLE_INDEX(snum
, zid
)] = zone
;
1694 #ifndef __HAVE_ARCH_MEMMAP_INIT
1695 #define memmap_init(size, nid, zone, start_pfn) \
1696 memmap_init_zone((size), (nid), (zone), (start_pfn))
1699 static int __cpuinit
zone_batchsize(struct zone
*zone
)
1704 * The per-cpu-pages pools are set to around 1000th of the
1705 * size of the zone. But no more than 1/2 of a meg.
1707 * OK, so we don't know how big the cache is. So guess.
1709 batch
= zone
->present_pages
/ 1024;
1710 if (batch
* PAGE_SIZE
> 512 * 1024)
1711 batch
= (512 * 1024) / PAGE_SIZE
;
1712 batch
/= 4; /* We effectively *= 4 below */
1717 * Clamp the batch to a 2^n - 1 value. Having a power
1718 * of 2 value was found to be more likely to have
1719 * suboptimal cache aliasing properties in some cases.
1721 * For example if 2 tasks are alternately allocating
1722 * batches of pages, one task can end up with a lot
1723 * of pages of one half of the possible page colors
1724 * and the other with pages of the other colors.
1726 batch
= (1 << (fls(batch
+ batch
/2)-1)) - 1;
1731 inline void setup_pageset(struct per_cpu_pageset
*p
, unsigned long batch
)
1733 struct per_cpu_pages
*pcp
;
1735 memset(p
, 0, sizeof(*p
));
1737 pcp
= &p
->pcp
[0]; /* hot */
1739 pcp
->high
= 6 * batch
;
1740 pcp
->batch
= max(1UL, 1 * batch
);
1741 INIT_LIST_HEAD(&pcp
->list
);
1743 pcp
= &p
->pcp
[1]; /* cold*/
1745 pcp
->high
= 2 * batch
;
1746 pcp
->batch
= max(1UL, batch
/2);
1747 INIT_LIST_HEAD(&pcp
->list
);
1751 * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
1752 * to the value high for the pageset p.
1755 static void setup_pagelist_highmark(struct per_cpu_pageset
*p
,
1758 struct per_cpu_pages
*pcp
;
1760 pcp
= &p
->pcp
[0]; /* hot list */
1762 pcp
->batch
= max(1UL, high
/4);
1763 if ((high
/4) > (PAGE_SHIFT
* 8))
1764 pcp
->batch
= PAGE_SHIFT
* 8;
1770 * Boot pageset table. One per cpu which is going to be used for all
1771 * zones and all nodes. The parameters will be set in such a way
1772 * that an item put on a list will immediately be handed over to
1773 * the buddy list. This is safe since pageset manipulation is done
1774 * with interrupts disabled.
1776 * Some NUMA counter updates may also be caught by the boot pagesets.
1778 * The boot_pagesets must be kept even after bootup is complete for
1779 * unused processors and/or zones. They do play a role for bootstrapping
1780 * hotplugged processors.
1782 * zoneinfo_show() and maybe other functions do
1783 * not check if the processor is online before following the pageset pointer.
1784 * Other parts of the kernel may not check if the zone is available.
1786 static struct per_cpu_pageset boot_pageset
[NR_CPUS
];
1789 * Dynamically allocate memory for the
1790 * per cpu pageset array in struct zone.
1792 static int __cpuinit
process_zones(int cpu
)
1794 struct zone
*zone
, *dzone
;
1796 for_each_zone(zone
) {
1798 zone_pcp(zone
, cpu
) = kmalloc_node(sizeof(struct per_cpu_pageset
),
1799 GFP_KERNEL
, cpu_to_node(cpu
));
1800 if (!zone_pcp(zone
, cpu
))
1803 setup_pageset(zone_pcp(zone
, cpu
), zone_batchsize(zone
));
1805 if (percpu_pagelist_fraction
)
1806 setup_pagelist_highmark(zone_pcp(zone
, cpu
),
1807 (zone
->present_pages
/ percpu_pagelist_fraction
));
1812 for_each_zone(dzone
) {
1815 kfree(zone_pcp(dzone
, cpu
));
1816 zone_pcp(dzone
, cpu
) = NULL
;
1821 static inline void free_zone_pagesets(int cpu
)
1825 for_each_zone(zone
) {
1826 struct per_cpu_pageset
*pset
= zone_pcp(zone
, cpu
);
1828 /* Free per_cpu_pageset if it is slab allocated */
1829 if (pset
!= &boot_pageset
[cpu
])
1831 zone_pcp(zone
, cpu
) = NULL
;
1835 static int __cpuinit
pageset_cpuup_callback(struct notifier_block
*nfb
,
1836 unsigned long action
,
1839 int cpu
= (long)hcpu
;
1840 int ret
= NOTIFY_OK
;
1843 case CPU_UP_PREPARE
:
1844 if (process_zones(cpu
))
1847 case CPU_UP_CANCELED
:
1849 free_zone_pagesets(cpu
);
1857 static struct notifier_block __cpuinitdata pageset_notifier
=
1858 { &pageset_cpuup_callback
, NULL
, 0 };
1860 void __init
setup_per_cpu_pageset(void)
1864 /* Initialize per_cpu_pageset for cpu 0.
1865 * A cpuup callback will do this for every cpu
1866 * as it comes online
1868 err
= process_zones(smp_processor_id());
1870 register_cpu_notifier(&pageset_notifier
);
1876 int zone_wait_table_init(struct zone
*zone
, unsigned long zone_size_pages
)
1879 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
1883 * The per-page waitqueue mechanism uses hashed waitqueues
1886 zone
->wait_table_hash_nr_entries
=
1887 wait_table_hash_nr_entries(zone_size_pages
);
1888 zone
->wait_table_bits
=
1889 wait_table_bits(zone
->wait_table_hash_nr_entries
);
1890 alloc_size
= zone
->wait_table_hash_nr_entries
1891 * sizeof(wait_queue_head_t
);
1893 if (system_state
== SYSTEM_BOOTING
) {
1894 zone
->wait_table
= (wait_queue_head_t
*)
1895 alloc_bootmem_node(pgdat
, alloc_size
);
1898 * This case means that a zone whose size was 0 gets new memory
1899 * via memory hot-add.
1900 * But it may be the case that a new node was hot-added. In
1901 * this case vmalloc() will not be able to use this new node's
1902 * memory - this wait_table must be initialized to use this new
1903 * node itself as well.
1904 * To use this new node's memory, further consideration will be
1907 zone
->wait_table
= (wait_queue_head_t
*)vmalloc(alloc_size
);
1909 if (!zone
->wait_table
)
1912 for(i
= 0; i
< zone
->wait_table_hash_nr_entries
; ++i
)
1913 init_waitqueue_head(zone
->wait_table
+ i
);
1918 static __meminit
void zone_pcp_init(struct zone
*zone
)
1921 unsigned long batch
= zone_batchsize(zone
);
1923 for (cpu
= 0; cpu
< NR_CPUS
; cpu
++) {
1925 /* Early boot. Slab allocator not functional yet */
1926 zone_pcp(zone
, cpu
) = &boot_pageset
[cpu
];
1927 setup_pageset(&boot_pageset
[cpu
],0);
1929 setup_pageset(zone_pcp(zone
,cpu
), batch
);
1932 if (zone
->present_pages
)
1933 printk(KERN_DEBUG
" %s zone: %lu pages, LIFO batch:%lu\n",
1934 zone
->name
, zone
->present_pages
, batch
);
1937 __meminit
int init_currently_empty_zone(struct zone
*zone
,
1938 unsigned long zone_start_pfn
,
1941 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
1943 ret
= zone_wait_table_init(zone
, size
);
1946 pgdat
->nr_zones
= zone_idx(zone
) + 1;
1948 zone
->zone_start_pfn
= zone_start_pfn
;
1950 memmap_init(size
, pgdat
->node_id
, zone_idx(zone
), zone_start_pfn
);
1952 zone_init_free_lists(pgdat
, zone
, zone
->spanned_pages
);
1958 * Set up the zone data structures:
1959 * - mark all pages reserved
1960 * - mark all memory queues empty
1961 * - clear the memory bitmaps
1963 static void __meminit
free_area_init_core(struct pglist_data
*pgdat
,
1964 unsigned long *zones_size
, unsigned long *zholes_size
)
1967 int nid
= pgdat
->node_id
;
1968 unsigned long zone_start_pfn
= pgdat
->node_start_pfn
;
1971 pgdat_resize_init(pgdat
);
1972 pgdat
->nr_zones
= 0;
1973 init_waitqueue_head(&pgdat
->kswapd_wait
);
1974 pgdat
->kswapd_max_order
= 0;
1976 for (j
= 0; j
< MAX_NR_ZONES
; j
++) {
1977 struct zone
*zone
= pgdat
->node_zones
+ j
;
1978 unsigned long size
, realsize
;
1980 realsize
= size
= zones_size
[j
];
1982 realsize
-= zholes_size
[j
];
1984 if (j
< ZONE_HIGHMEM
)
1985 nr_kernel_pages
+= realsize
;
1986 nr_all_pages
+= realsize
;
1988 zone
->spanned_pages
= size
;
1989 zone
->present_pages
= realsize
;
1991 zone
->min_unmapped_ratio
= (realsize
*sysctl_min_unmapped_ratio
)
1994 zone
->name
= zone_names
[j
];
1995 spin_lock_init(&zone
->lock
);
1996 spin_lock_init(&zone
->lru_lock
);
1997 zone_seqlock_init(zone
);
1998 zone
->zone_pgdat
= pgdat
;
1999 zone
->free_pages
= 0;
2001 zone
->temp_priority
= zone
->prev_priority
= DEF_PRIORITY
;
2003 zone_pcp_init(zone
);
2004 INIT_LIST_HEAD(&zone
->active_list
);
2005 INIT_LIST_HEAD(&zone
->inactive_list
);
2006 zone
->nr_scan_active
= 0;
2007 zone
->nr_scan_inactive
= 0;
2008 zone
->nr_active
= 0;
2009 zone
->nr_inactive
= 0;
2010 zap_zone_vm_stats(zone
);
2011 atomic_set(&zone
->reclaim_in_progress
, 0);
2015 zonetable_add(zone
, nid
, j
, zone_start_pfn
, size
);
2016 ret
= init_currently_empty_zone(zone
, zone_start_pfn
, size
);
2018 zone_start_pfn
+= size
;
2022 static void __init
alloc_node_mem_map(struct pglist_data
*pgdat
)
2024 /* Skip empty nodes */
2025 if (!pgdat
->node_spanned_pages
)
2028 #ifdef CONFIG_FLAT_NODE_MEM_MAP
2029 /* ia64 gets its own node_mem_map, before this, without bootmem */
2030 if (!pgdat
->node_mem_map
) {
2031 unsigned long size
, start
, end
;
2035 * The zone's endpoints aren't required to be MAX_ORDER
2036 * aligned but the node_mem_map endpoints must be in order
2037 * for the buddy allocator to function correctly.
2039 start
= pgdat
->node_start_pfn
& ~(MAX_ORDER_NR_PAGES
- 1);
2040 end
= pgdat
->node_start_pfn
+ pgdat
->node_spanned_pages
;
2041 end
= ALIGN(end
, MAX_ORDER_NR_PAGES
);
2042 size
= (end
- start
) * sizeof(struct page
);
2043 map
= alloc_remap(pgdat
->node_id
, size
);
2045 map
= alloc_bootmem_node(pgdat
, size
);
2046 pgdat
->node_mem_map
= map
+ (pgdat
->node_start_pfn
- start
);
2048 #ifdef CONFIG_FLATMEM
2050 * With no DISCONTIG, the global mem_map is just set as node 0's
2052 if (pgdat
== NODE_DATA(0))
2053 mem_map
= NODE_DATA(0)->node_mem_map
;
2055 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
2058 void __meminit
free_area_init_node(int nid
, struct pglist_data
*pgdat
,
2059 unsigned long *zones_size
, unsigned long node_start_pfn
,
2060 unsigned long *zholes_size
)
2062 pgdat
->node_id
= nid
;
2063 pgdat
->node_start_pfn
= node_start_pfn
;
2064 calculate_zone_totalpages(pgdat
, zones_size
, zholes_size
);
2066 alloc_node_mem_map(pgdat
);
2068 free_area_init_core(pgdat
, zones_size
, zholes_size
);
2071 #ifndef CONFIG_NEED_MULTIPLE_NODES
2072 static bootmem_data_t contig_bootmem_data
;
2073 struct pglist_data contig_page_data
= { .bdata
= &contig_bootmem_data
};
2075 EXPORT_SYMBOL(contig_page_data
);
2078 void __init
free_area_init(unsigned long *zones_size
)
2080 free_area_init_node(0, NODE_DATA(0), zones_size
,
2081 __pa(PAGE_OFFSET
) >> PAGE_SHIFT
, NULL
);
2084 #ifdef CONFIG_HOTPLUG_CPU
2085 static int page_alloc_cpu_notify(struct notifier_block
*self
,
2086 unsigned long action
, void *hcpu
)
2088 int cpu
= (unsigned long)hcpu
;
2090 if (action
== CPU_DEAD
) {
2091 local_irq_disable();
2093 vm_events_fold_cpu(cpu
);
2095 refresh_cpu_vm_stats(cpu
);
2099 #endif /* CONFIG_HOTPLUG_CPU */
2101 void __init
page_alloc_init(void)
2103 hotcpu_notifier(page_alloc_cpu_notify
, 0);
2107 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
2108 * or min_free_kbytes changes.
2110 static void calculate_totalreserve_pages(void)
2112 struct pglist_data
*pgdat
;
2113 unsigned long reserve_pages
= 0;
2116 for_each_online_pgdat(pgdat
) {
2117 for (i
= 0; i
< MAX_NR_ZONES
; i
++) {
2118 struct zone
*zone
= pgdat
->node_zones
+ i
;
2119 unsigned long max
= 0;
2121 /* Find valid and maximum lowmem_reserve in the zone */
2122 for (j
= i
; j
< MAX_NR_ZONES
; j
++) {
2123 if (zone
->lowmem_reserve
[j
] > max
)
2124 max
= zone
->lowmem_reserve
[j
];
2127 /* we treat pages_high as reserved pages. */
2128 max
+= zone
->pages_high
;
2130 if (max
> zone
->present_pages
)
2131 max
= zone
->present_pages
;
2132 reserve_pages
+= max
;
2135 totalreserve_pages
= reserve_pages
;
2139 * setup_per_zone_lowmem_reserve - called whenever
2140 * sysctl_lower_zone_reserve_ratio changes. Ensures that each zone
2141 * has a correct pages reserved value, so an adequate number of
2142 * pages are left in the zone after a successful __alloc_pages().
2144 static void setup_per_zone_lowmem_reserve(void)
2146 struct pglist_data
*pgdat
;
2149 for_each_online_pgdat(pgdat
) {
2150 for (j
= 0; j
< MAX_NR_ZONES
; j
++) {
2151 struct zone
*zone
= pgdat
->node_zones
+ j
;
2152 unsigned long present_pages
= zone
->present_pages
;
2154 zone
->lowmem_reserve
[j
] = 0;
2156 for (idx
= j
-1; idx
>= 0; idx
--) {
2157 struct zone
*lower_zone
;
2159 if (sysctl_lowmem_reserve_ratio
[idx
] < 1)
2160 sysctl_lowmem_reserve_ratio
[idx
] = 1;
2162 lower_zone
= pgdat
->node_zones
+ idx
;
2163 lower_zone
->lowmem_reserve
[j
] = present_pages
/
2164 sysctl_lowmem_reserve_ratio
[idx
];
2165 present_pages
+= lower_zone
->present_pages
;
2170 /* update totalreserve_pages */
2171 calculate_totalreserve_pages();
2175 * setup_per_zone_pages_min - called when min_free_kbytes changes. Ensures
2176 * that the pages_{min,low,high} values for each zone are set correctly
2177 * with respect to min_free_kbytes.
2179 void setup_per_zone_pages_min(void)
2181 unsigned long pages_min
= min_free_kbytes
>> (PAGE_SHIFT
- 10);
2182 unsigned long lowmem_pages
= 0;
2184 unsigned long flags
;
2186 /* Calculate total number of !ZONE_HIGHMEM pages */
2187 for_each_zone(zone
) {
2188 if (!is_highmem(zone
))
2189 lowmem_pages
+= zone
->present_pages
;
2192 for_each_zone(zone
) {
2195 spin_lock_irqsave(&zone
->lru_lock
, flags
);
2196 tmp
= (u64
)pages_min
* zone
->present_pages
;
2197 do_div(tmp
, lowmem_pages
);
2198 if (is_highmem(zone
)) {
2200 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
2201 * need highmem pages, so cap pages_min to a small
2204 * The (pages_high-pages_low) and (pages_low-pages_min)
2205 * deltas controls asynch page reclaim, and so should
2206 * not be capped for highmem.
2210 min_pages
= zone
->present_pages
/ 1024;
2211 if (min_pages
< SWAP_CLUSTER_MAX
)
2212 min_pages
= SWAP_CLUSTER_MAX
;
2213 if (min_pages
> 128)
2215 zone
->pages_min
= min_pages
;
2218 * If it's a lowmem zone, reserve a number of pages
2219 * proportionate to the zone's size.
2221 zone
->pages_min
= tmp
;
2224 zone
->pages_low
= zone
->pages_min
+ (tmp
>> 2);
2225 zone
->pages_high
= zone
->pages_min
+ (tmp
>> 1);
2226 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
2229 /* update totalreserve_pages */
2230 calculate_totalreserve_pages();
2234 * Initialise min_free_kbytes.
2236 * For small machines we want it small (128k min). For large machines
2237 * we want it large (64MB max). But it is not linear, because network
2238 * bandwidth does not increase linearly with machine size. We use
2240 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
2241 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
2257 static int __init
init_per_zone_pages_min(void)
2259 unsigned long lowmem_kbytes
;
2261 lowmem_kbytes
= nr_free_buffer_pages() * (PAGE_SIZE
>> 10);
2263 min_free_kbytes
= int_sqrt(lowmem_kbytes
* 16);
2264 if (min_free_kbytes
< 128)
2265 min_free_kbytes
= 128;
2266 if (min_free_kbytes
> 65536)
2267 min_free_kbytes
= 65536;
2268 setup_per_zone_pages_min();
2269 setup_per_zone_lowmem_reserve();
2272 module_init(init_per_zone_pages_min
)
2275 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
2276 * that we can call two helper functions whenever min_free_kbytes
2279 int min_free_kbytes_sysctl_handler(ctl_table
*table
, int write
,
2280 struct file
*file
, void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2282 proc_dointvec(table
, write
, file
, buffer
, length
, ppos
);
2283 setup_per_zone_pages_min();
2288 int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table
*table
, int write
,
2289 struct file
*file
, void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2294 rc
= proc_dointvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
2299 zone
->min_unmapped_ratio
= (zone
->present_pages
*
2300 sysctl_min_unmapped_ratio
) / 100;
2306 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
2307 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
2308 * whenever sysctl_lowmem_reserve_ratio changes.
2310 * The reserve ratio obviously has absolutely no relation with the
2311 * pages_min watermarks. The lowmem reserve ratio can only make sense
2312 * if in function of the boot time zone sizes.
2314 int lowmem_reserve_ratio_sysctl_handler(ctl_table
*table
, int write
,
2315 struct file
*file
, void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2317 proc_dointvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
2318 setup_per_zone_lowmem_reserve();
2323 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
2324 * cpu. It is the fraction of total pages in each zone that a hot per cpu pagelist
2325 * can have before it gets flushed back to buddy allocator.
2328 int percpu_pagelist_fraction_sysctl_handler(ctl_table
*table
, int write
,
2329 struct file
*file
, void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2335 ret
= proc_dointvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
2336 if (!write
|| (ret
== -EINVAL
))
2338 for_each_zone(zone
) {
2339 for_each_online_cpu(cpu
) {
2341 high
= zone
->present_pages
/ percpu_pagelist_fraction
;
2342 setup_pagelist_highmark(zone_pcp(zone
, cpu
), high
);
2348 int hashdist
= HASHDIST_DEFAULT
;
2351 static int __init
set_hashdist(char *str
)
2355 hashdist
= simple_strtoul(str
, &str
, 0);
2358 __setup("hashdist=", set_hashdist
);
2362 * allocate a large system hash table from bootmem
2363 * - it is assumed that the hash table must contain an exact power-of-2
2364 * quantity of entries
2365 * - limit is the number of hash buckets, not the total allocation size
2367 void *__init
alloc_large_system_hash(const char *tablename
,
2368 unsigned long bucketsize
,
2369 unsigned long numentries
,
2372 unsigned int *_hash_shift
,
2373 unsigned int *_hash_mask
,
2374 unsigned long limit
)
2376 unsigned long long max
= limit
;
2377 unsigned long log2qty
, size
;
2380 /* allow the kernel cmdline to have a say */
2382 /* round applicable memory size up to nearest megabyte */
2383 numentries
= (flags
& HASH_HIGHMEM
) ? nr_all_pages
: nr_kernel_pages
;
2384 numentries
+= (1UL << (20 - PAGE_SHIFT
)) - 1;
2385 numentries
>>= 20 - PAGE_SHIFT
;
2386 numentries
<<= 20 - PAGE_SHIFT
;
2388 /* limit to 1 bucket per 2^scale bytes of low memory */
2389 if (scale
> PAGE_SHIFT
)
2390 numentries
>>= (scale
- PAGE_SHIFT
);
2392 numentries
<<= (PAGE_SHIFT
- scale
);
2394 numentries
= roundup_pow_of_two(numentries
);
2396 /* limit allocation size to 1/16 total memory by default */
2398 max
= ((unsigned long long)nr_all_pages
<< PAGE_SHIFT
) >> 4;
2399 do_div(max
, bucketsize
);
2402 if (numentries
> max
)
2405 log2qty
= long_log2(numentries
);
2408 size
= bucketsize
<< log2qty
;
2409 if (flags
& HASH_EARLY
)
2410 table
= alloc_bootmem(size
);
2412 table
= __vmalloc(size
, GFP_ATOMIC
, PAGE_KERNEL
);
2414 unsigned long order
;
2415 for (order
= 0; ((1UL << order
) << PAGE_SHIFT
) < size
; order
++)
2417 table
= (void*) __get_free_pages(GFP_ATOMIC
, order
);
2419 } while (!table
&& size
> PAGE_SIZE
&& --log2qty
);
2422 panic("Failed to allocate %s hash table\n", tablename
);
2424 printk("%s hash table entries: %d (order: %d, %lu bytes)\n",
2427 long_log2(size
) - PAGE_SHIFT
,
2431 *_hash_shift
= log2qty
;
2433 *_hash_mask
= (1 << log2qty
) - 1;
2438 #ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
2439 struct page
*pfn_to_page(unsigned long pfn
)
2441 return __pfn_to_page(pfn
);
2443 unsigned long page_to_pfn(struct page
*page
)
2445 return __page_to_pfn(page
);
2447 EXPORT_SYMBOL(pfn_to_page
);
2448 EXPORT_SYMBOL(page_to_pfn
);
2449 #endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */