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] = {
73 #ifdef CONFIG_ZONE_DMA32
81 EXPORT_SYMBOL(totalram_pages
);
84 * Used by page_zone() to look up the address of the struct zone whose
85 * id is encoded in the upper bits of page->flags
87 struct zone
*zone_table
[1 << ZONETABLE_SHIFT
] __read_mostly
;
88 EXPORT_SYMBOL(zone_table
);
90 static char *zone_names
[MAX_NR_ZONES
] = {
92 #ifdef CONFIG_ZONE_DMA32
101 int min_free_kbytes
= 1024;
103 unsigned long __meminitdata nr_kernel_pages
;
104 unsigned long __meminitdata nr_all_pages
;
106 #ifdef CONFIG_DEBUG_VM
107 static int page_outside_zone_boundaries(struct zone
*zone
, struct page
*page
)
111 unsigned long pfn
= page_to_pfn(page
);
114 seq
= zone_span_seqbegin(zone
);
115 if (pfn
>= zone
->zone_start_pfn
+ zone
->spanned_pages
)
117 else if (pfn
< zone
->zone_start_pfn
)
119 } while (zone_span_seqretry(zone
, seq
));
124 static int page_is_consistent(struct zone
*zone
, struct page
*page
)
126 #ifdef CONFIG_HOLES_IN_ZONE
127 if (!pfn_valid(page_to_pfn(page
)))
130 if (zone
!= page_zone(page
))
136 * Temporary debugging check for pages not lying within a given zone.
138 static int bad_range(struct zone
*zone
, struct page
*page
)
140 if (page_outside_zone_boundaries(zone
, page
))
142 if (!page_is_consistent(zone
, page
))
148 static inline int bad_range(struct zone
*zone
, struct page
*page
)
154 static void bad_page(struct page
*page
)
156 printk(KERN_EMERG
"Bad page state in process '%s'\n"
157 KERN_EMERG
"page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n"
158 KERN_EMERG
"Trying to fix it up, but a reboot is needed\n"
159 KERN_EMERG
"Backtrace:\n",
160 current
->comm
, page
, (int)(2*sizeof(unsigned long)),
161 (unsigned long)page
->flags
, page
->mapping
,
162 page_mapcount(page
), page_count(page
));
164 page
->flags
&= ~(1 << PG_lru
|
174 set_page_count(page
, 0);
175 reset_page_mapcount(page
);
176 page
->mapping
= NULL
;
177 add_taint(TAINT_BAD_PAGE
);
181 * Higher-order pages are called "compound pages". They are structured thusly:
183 * The first PAGE_SIZE page is called the "head page".
185 * The remaining PAGE_SIZE pages are called "tail pages".
187 * All pages have PG_compound set. All pages have their ->private pointing at
188 * the head page (even the head page has this).
190 * The first tail page's ->lru.next holds the address of the compound page's
191 * put_page() function. Its ->lru.prev holds the order of allocation.
192 * This usage means that zero-order pages may not be compound.
195 static void free_compound_page(struct page
*page
)
197 __free_pages_ok(page
, (unsigned long)page
[1].lru
.prev
);
200 static void prep_compound_page(struct page
*page
, unsigned long order
)
203 int nr_pages
= 1 << order
;
205 page
[1].lru
.next
= (void *)free_compound_page
; /* set dtor */
206 page
[1].lru
.prev
= (void *)order
;
207 for (i
= 0; i
< nr_pages
; i
++) {
208 struct page
*p
= page
+ i
;
210 __SetPageCompound(p
);
211 set_page_private(p
, (unsigned long)page
);
215 static void destroy_compound_page(struct page
*page
, unsigned long order
)
218 int nr_pages
= 1 << order
;
220 if (unlikely((unsigned long)page
[1].lru
.prev
!= order
))
223 for (i
= 0; i
< nr_pages
; i
++) {
224 struct page
*p
= page
+ i
;
226 if (unlikely(!PageCompound(p
) |
227 (page_private(p
) != (unsigned long)page
)))
229 __ClearPageCompound(p
);
233 static inline void prep_zero_page(struct page
*page
, int order
, gfp_t gfp_flags
)
237 VM_BUG_ON((gfp_flags
& (__GFP_WAIT
| __GFP_HIGHMEM
)) == __GFP_HIGHMEM
);
239 * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
240 * and __GFP_HIGHMEM from hard or soft interrupt context.
242 VM_BUG_ON((gfp_flags
& __GFP_HIGHMEM
) && in_interrupt());
243 for (i
= 0; i
< (1 << order
); i
++)
244 clear_highpage(page
+ i
);
248 * function for dealing with page's order in buddy system.
249 * zone->lock is already acquired when we use these.
250 * So, we don't need atomic page->flags operations here.
252 static inline unsigned long page_order(struct page
*page
)
254 return page_private(page
);
257 static inline void set_page_order(struct page
*page
, int order
)
259 set_page_private(page
, order
);
260 __SetPageBuddy(page
);
263 static inline void rmv_page_order(struct page
*page
)
265 __ClearPageBuddy(page
);
266 set_page_private(page
, 0);
270 * Locate the struct page for both the matching buddy in our
271 * pair (buddy1) and the combined O(n+1) page they form (page).
273 * 1) Any buddy B1 will have an order O twin B2 which satisfies
274 * the following equation:
276 * For example, if the starting buddy (buddy2) is #8 its order
278 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
280 * 2) Any buddy B will have an order O+1 parent P which
281 * satisfies the following equation:
284 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
286 static inline struct page
*
287 __page_find_buddy(struct page
*page
, unsigned long page_idx
, unsigned int order
)
289 unsigned long buddy_idx
= page_idx
^ (1 << order
);
291 return page
+ (buddy_idx
- page_idx
);
294 static inline unsigned long
295 __find_combined_index(unsigned long page_idx
, unsigned int order
)
297 return (page_idx
& ~(1 << order
));
301 * This function checks whether a page is free && is the buddy
302 * we can do coalesce a page and its buddy if
303 * (a) the buddy is not in a hole &&
304 * (b) the buddy is in the buddy system &&
305 * (c) a page and its buddy have the same order &&
306 * (d) a page and its buddy are in the same zone.
308 * For recording whether a page is in the buddy system, we use PG_buddy.
309 * Setting, clearing, and testing PG_buddy is serialized by zone->lock.
311 * For recording page's order, we use page_private(page).
313 static inline int page_is_buddy(struct page
*page
, struct page
*buddy
,
316 #ifdef CONFIG_HOLES_IN_ZONE
317 if (!pfn_valid(page_to_pfn(buddy
)))
321 if (page_zone_id(page
) != page_zone_id(buddy
))
324 if (PageBuddy(buddy
) && page_order(buddy
) == order
) {
325 BUG_ON(page_count(buddy
) != 0);
332 * Freeing function for a buddy system allocator.
334 * The concept of a buddy system is to maintain direct-mapped table
335 * (containing bit values) for memory blocks of various "orders".
336 * The bottom level table contains the map for the smallest allocatable
337 * units of memory (here, pages), and each level above it describes
338 * pairs of units from the levels below, hence, "buddies".
339 * At a high level, all that happens here is marking the table entry
340 * at the bottom level available, and propagating the changes upward
341 * as necessary, plus some accounting needed to play nicely with other
342 * parts of the VM system.
343 * At each level, we keep a list of pages, which are heads of continuous
344 * free pages of length of (1 << order) and marked with PG_buddy. Page's
345 * order is recorded in page_private(page) field.
346 * So when we are allocating or freeing one, we can derive the state of the
347 * other. That is, if we allocate a small block, and both were
348 * free, the remainder of the region must be split into blocks.
349 * If a block is freed, and its buddy is also free, then this
350 * triggers coalescing into a block of larger size.
355 static inline void __free_one_page(struct page
*page
,
356 struct zone
*zone
, unsigned int order
)
358 unsigned long page_idx
;
359 int order_size
= 1 << order
;
361 if (unlikely(PageCompound(page
)))
362 destroy_compound_page(page
, order
);
364 page_idx
= page_to_pfn(page
) & ((1 << MAX_ORDER
) - 1);
366 VM_BUG_ON(page_idx
& (order_size
- 1));
367 VM_BUG_ON(bad_range(zone
, page
));
369 zone
->free_pages
+= order_size
;
370 while (order
< MAX_ORDER
-1) {
371 unsigned long combined_idx
;
372 struct free_area
*area
;
375 buddy
= __page_find_buddy(page
, page_idx
, order
);
376 if (!page_is_buddy(page
, buddy
, order
))
377 break; /* Move the buddy up one level. */
379 list_del(&buddy
->lru
);
380 area
= zone
->free_area
+ order
;
382 rmv_page_order(buddy
);
383 combined_idx
= __find_combined_index(page_idx
, order
);
384 page
= page
+ (combined_idx
- page_idx
);
385 page_idx
= combined_idx
;
388 set_page_order(page
, order
);
389 list_add(&page
->lru
, &zone
->free_area
[order
].free_list
);
390 zone
->free_area
[order
].nr_free
++;
393 static inline int free_pages_check(struct page
*page
)
395 if (unlikely(page_mapcount(page
) |
396 (page
->mapping
!= NULL
) |
397 (page_count(page
) != 0) |
411 __ClearPageDirty(page
);
413 * For now, we report if PG_reserved was found set, but do not
414 * clear it, and do not free the page. But we shall soon need
415 * to do more, for when the ZERO_PAGE count wraps negative.
417 return PageReserved(page
);
421 * Frees a list of pages.
422 * Assumes all pages on list are in same zone, and of same order.
423 * count is the number of pages to free.
425 * If the zone was previously in an "all pages pinned" state then look to
426 * see if this freeing clears that state.
428 * And clear the zone's pages_scanned counter, to hold off the "all pages are
429 * pinned" detection logic.
431 static void free_pages_bulk(struct zone
*zone
, int count
,
432 struct list_head
*list
, int order
)
434 spin_lock(&zone
->lock
);
435 zone
->all_unreclaimable
= 0;
436 zone
->pages_scanned
= 0;
440 VM_BUG_ON(list_empty(list
));
441 page
= list_entry(list
->prev
, struct page
, lru
);
442 /* have to delete it as __free_one_page list manipulates */
443 list_del(&page
->lru
);
444 __free_one_page(page
, zone
, order
);
446 spin_unlock(&zone
->lock
);
449 static void free_one_page(struct zone
*zone
, struct page
*page
, int order
)
452 list_add(&page
->lru
, &list
);
453 free_pages_bulk(zone
, 1, &list
, order
);
456 static void __free_pages_ok(struct page
*page
, unsigned int order
)
462 arch_free_page(page
, order
);
463 if (!PageHighMem(page
))
464 debug_check_no_locks_freed(page_address(page
),
467 for (i
= 0 ; i
< (1 << order
) ; ++i
)
468 reserved
+= free_pages_check(page
+ i
);
472 kernel_map_pages(page
, 1 << order
, 0);
473 local_irq_save(flags
);
474 __count_vm_events(PGFREE
, 1 << order
);
475 free_one_page(page_zone(page
), page
, order
);
476 local_irq_restore(flags
);
480 * permit the bootmem allocator to evade page validation on high-order frees
482 void fastcall __init
__free_pages_bootmem(struct page
*page
, unsigned int order
)
485 __ClearPageReserved(page
);
486 set_page_count(page
, 0);
487 set_page_refcounted(page
);
493 for (loop
= 0; loop
< BITS_PER_LONG
; loop
++) {
494 struct page
*p
= &page
[loop
];
496 if (loop
+ 1 < BITS_PER_LONG
)
498 __ClearPageReserved(p
);
499 set_page_count(p
, 0);
502 set_page_refcounted(page
);
503 __free_pages(page
, order
);
509 * The order of subdivision here is critical for the IO subsystem.
510 * Please do not alter this order without good reasons and regression
511 * testing. Specifically, as large blocks of memory are subdivided,
512 * the order in which smaller blocks are delivered depends on the order
513 * they're subdivided in this function. This is the primary factor
514 * influencing the order in which pages are delivered to the IO
515 * subsystem according to empirical testing, and this is also justified
516 * by considering the behavior of a buddy system containing a single
517 * large block of memory acted on by a series of small allocations.
518 * This behavior is a critical factor in sglist merging's success.
522 static inline void expand(struct zone
*zone
, struct page
*page
,
523 int low
, int high
, struct free_area
*area
)
525 unsigned long size
= 1 << high
;
531 VM_BUG_ON(bad_range(zone
, &page
[size
]));
532 list_add(&page
[size
].lru
, &area
->free_list
);
534 set_page_order(&page
[size
], high
);
539 * This page is about to be returned from the page allocator
541 static int prep_new_page(struct page
*page
, int order
, gfp_t gfp_flags
)
543 if (unlikely(page_mapcount(page
) |
544 (page
->mapping
!= NULL
) |
545 (page_count(page
) != 0) |
561 * For now, we report if PG_reserved was found set, but do not
562 * clear it, and do not allocate the page: as a safety net.
564 if (PageReserved(page
))
567 page
->flags
&= ~(1 << PG_uptodate
| 1 << PG_error
|
568 1 << PG_referenced
| 1 << PG_arch_1
|
569 1 << PG_checked
| 1 << PG_mappedtodisk
);
570 set_page_private(page
, 0);
571 set_page_refcounted(page
);
572 kernel_map_pages(page
, 1 << order
, 1);
574 if (gfp_flags
& __GFP_ZERO
)
575 prep_zero_page(page
, order
, gfp_flags
);
577 if (order
&& (gfp_flags
& __GFP_COMP
))
578 prep_compound_page(page
, order
);
584 * Do the hard work of removing an element from the buddy allocator.
585 * Call me with the zone->lock already held.
587 static struct page
*__rmqueue(struct zone
*zone
, unsigned int order
)
589 struct free_area
* area
;
590 unsigned int current_order
;
593 for (current_order
= order
; current_order
< MAX_ORDER
; ++current_order
) {
594 area
= zone
->free_area
+ current_order
;
595 if (list_empty(&area
->free_list
))
598 page
= list_entry(area
->free_list
.next
, struct page
, lru
);
599 list_del(&page
->lru
);
600 rmv_page_order(page
);
602 zone
->free_pages
-= 1UL << order
;
603 expand(zone
, page
, order
, current_order
, area
);
611 * Obtain a specified number of elements from the buddy allocator, all under
612 * a single hold of the lock, for efficiency. Add them to the supplied list.
613 * Returns the number of new pages which were placed at *list.
615 static int rmqueue_bulk(struct zone
*zone
, unsigned int order
,
616 unsigned long count
, struct list_head
*list
)
620 spin_lock(&zone
->lock
);
621 for (i
= 0; i
< count
; ++i
) {
622 struct page
*page
= __rmqueue(zone
, order
);
623 if (unlikely(page
== NULL
))
625 list_add_tail(&page
->lru
, list
);
627 spin_unlock(&zone
->lock
);
633 * Called from the slab reaper to drain pagesets on a particular node that
634 * belong to the currently executing processor.
635 * Note that this function must be called with the thread pinned to
636 * a single processor.
638 void drain_node_pages(int nodeid
)
644 for (z
= 0; z
< MAX_NR_ZONES
; z
++) {
645 struct zone
*zone
= NODE_DATA(nodeid
)->node_zones
+ z
;
646 struct per_cpu_pageset
*pset
;
648 pset
= zone_pcp(zone
, smp_processor_id());
649 for (i
= 0; i
< ARRAY_SIZE(pset
->pcp
); i
++) {
650 struct per_cpu_pages
*pcp
;
654 local_irq_save(flags
);
655 free_pages_bulk(zone
, pcp
->count
, &pcp
->list
, 0);
657 local_irq_restore(flags
);
664 #if defined(CONFIG_PM) || defined(CONFIG_HOTPLUG_CPU)
665 static void __drain_pages(unsigned int cpu
)
671 for_each_zone(zone
) {
672 struct per_cpu_pageset
*pset
;
674 pset
= zone_pcp(zone
, cpu
);
675 for (i
= 0; i
< ARRAY_SIZE(pset
->pcp
); i
++) {
676 struct per_cpu_pages
*pcp
;
679 local_irq_save(flags
);
680 free_pages_bulk(zone
, pcp
->count
, &pcp
->list
, 0);
682 local_irq_restore(flags
);
686 #endif /* CONFIG_PM || CONFIG_HOTPLUG_CPU */
690 void mark_free_pages(struct zone
*zone
)
692 unsigned long zone_pfn
, flags
;
694 struct list_head
*curr
;
696 if (!zone
->spanned_pages
)
699 spin_lock_irqsave(&zone
->lock
, flags
);
700 for (zone_pfn
= 0; zone_pfn
< zone
->spanned_pages
; ++zone_pfn
)
701 ClearPageNosaveFree(pfn_to_page(zone_pfn
+ zone
->zone_start_pfn
));
703 for (order
= MAX_ORDER
- 1; order
>= 0; --order
)
704 list_for_each(curr
, &zone
->free_area
[order
].free_list
) {
705 unsigned long start_pfn
, i
;
707 start_pfn
= page_to_pfn(list_entry(curr
, struct page
, lru
));
709 for (i
=0; i
< (1<<order
); i
++)
710 SetPageNosaveFree(pfn_to_page(start_pfn
+i
));
712 spin_unlock_irqrestore(&zone
->lock
, flags
);
716 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
718 void drain_local_pages(void)
722 local_irq_save(flags
);
723 __drain_pages(smp_processor_id());
724 local_irq_restore(flags
);
726 #endif /* CONFIG_PM */
729 * Free a 0-order page
731 static void fastcall
free_hot_cold_page(struct page
*page
, int cold
)
733 struct zone
*zone
= page_zone(page
);
734 struct per_cpu_pages
*pcp
;
737 arch_free_page(page
, 0);
740 page
->mapping
= NULL
;
741 if (free_pages_check(page
))
744 kernel_map_pages(page
, 1, 0);
746 pcp
= &zone_pcp(zone
, get_cpu())->pcp
[cold
];
747 local_irq_save(flags
);
748 __count_vm_event(PGFREE
);
749 list_add(&page
->lru
, &pcp
->list
);
751 if (pcp
->count
>= pcp
->high
) {
752 free_pages_bulk(zone
, pcp
->batch
, &pcp
->list
, 0);
753 pcp
->count
-= pcp
->batch
;
755 local_irq_restore(flags
);
759 void fastcall
free_hot_page(struct page
*page
)
761 free_hot_cold_page(page
, 0);
764 void fastcall
free_cold_page(struct page
*page
)
766 free_hot_cold_page(page
, 1);
770 * split_page takes a non-compound higher-order page, and splits it into
771 * n (1<<order) sub-pages: page[0..n]
772 * Each sub-page must be freed individually.
774 * Note: this is probably too low level an operation for use in drivers.
775 * Please consult with lkml before using this in your driver.
777 void split_page(struct page
*page
, unsigned int order
)
781 VM_BUG_ON(PageCompound(page
));
782 VM_BUG_ON(!page_count(page
));
783 for (i
= 1; i
< (1 << order
); i
++)
784 set_page_refcounted(page
+ i
);
788 * Really, prep_compound_page() should be called from __rmqueue_bulk(). But
789 * we cheat by calling it from here, in the order > 0 path. Saves a branch
792 static struct page
*buffered_rmqueue(struct zonelist
*zonelist
,
793 struct zone
*zone
, int order
, gfp_t gfp_flags
)
797 int cold
= !!(gfp_flags
& __GFP_COLD
);
802 if (likely(order
== 0)) {
803 struct per_cpu_pages
*pcp
;
805 pcp
= &zone_pcp(zone
, cpu
)->pcp
[cold
];
806 local_irq_save(flags
);
808 pcp
->count
+= rmqueue_bulk(zone
, 0,
809 pcp
->batch
, &pcp
->list
);
810 if (unlikely(!pcp
->count
))
813 page
= list_entry(pcp
->list
.next
, struct page
, lru
);
814 list_del(&page
->lru
);
817 spin_lock_irqsave(&zone
->lock
, flags
);
818 page
= __rmqueue(zone
, order
);
819 spin_unlock(&zone
->lock
);
824 __count_zone_vm_events(PGALLOC
, zone
, 1 << order
);
825 zone_statistics(zonelist
, zone
);
826 local_irq_restore(flags
);
829 VM_BUG_ON(bad_range(zone
, page
));
830 if (prep_new_page(page
, order
, gfp_flags
))
835 local_irq_restore(flags
);
840 #define ALLOC_NO_WATERMARKS 0x01 /* don't check watermarks at all */
841 #define ALLOC_WMARK_MIN 0x02 /* use pages_min watermark */
842 #define ALLOC_WMARK_LOW 0x04 /* use pages_low watermark */
843 #define ALLOC_WMARK_HIGH 0x08 /* use pages_high watermark */
844 #define ALLOC_HARDER 0x10 /* try to alloc harder */
845 #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
846 #define ALLOC_CPUSET 0x40 /* check for correct cpuset */
849 * Return 1 if free pages are above 'mark'. This takes into account the order
852 int zone_watermark_ok(struct zone
*z
, int order
, unsigned long mark
,
853 int classzone_idx
, int alloc_flags
)
855 /* free_pages my go negative - that's OK */
856 long min
= mark
, free_pages
= z
->free_pages
- (1 << order
) + 1;
859 if (alloc_flags
& ALLOC_HIGH
)
861 if (alloc_flags
& ALLOC_HARDER
)
864 if (free_pages
<= min
+ z
->lowmem_reserve
[classzone_idx
])
866 for (o
= 0; o
< order
; o
++) {
867 /* At the next order, this order's pages become unavailable */
868 free_pages
-= z
->free_area
[o
].nr_free
<< o
;
870 /* Require fewer higher order pages to be free */
873 if (free_pages
<= min
)
880 * get_page_from_freeliest goes through the zonelist trying to allocate
884 get_page_from_freelist(gfp_t gfp_mask
, unsigned int order
,
885 struct zonelist
*zonelist
, int alloc_flags
)
887 struct zone
**z
= zonelist
->zones
;
888 struct page
*page
= NULL
;
889 int classzone_idx
= zone_idx(*z
);
892 * Go through the zonelist once, looking for a zone with enough free.
893 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
896 if ((alloc_flags
& ALLOC_CPUSET
) &&
897 !cpuset_zone_allowed(*z
, gfp_mask
))
900 if (!(alloc_flags
& ALLOC_NO_WATERMARKS
)) {
902 if (alloc_flags
& ALLOC_WMARK_MIN
)
903 mark
= (*z
)->pages_min
;
904 else if (alloc_flags
& ALLOC_WMARK_LOW
)
905 mark
= (*z
)->pages_low
;
907 mark
= (*z
)->pages_high
;
908 if (!zone_watermark_ok(*z
, order
, mark
,
909 classzone_idx
, alloc_flags
))
910 if (!zone_reclaim_mode
||
911 !zone_reclaim(*z
, gfp_mask
, order
))
915 page
= buffered_rmqueue(zonelist
, *z
, order
, gfp_mask
);
919 } while (*(++z
) != NULL
);
924 * This is the 'heart' of the zoned buddy allocator.
926 struct page
* fastcall
927 __alloc_pages(gfp_t gfp_mask
, unsigned int order
,
928 struct zonelist
*zonelist
)
930 const gfp_t wait
= gfp_mask
& __GFP_WAIT
;
933 struct reclaim_state reclaim_state
;
934 struct task_struct
*p
= current
;
937 int did_some_progress
;
939 might_sleep_if(wait
);
942 z
= zonelist
->zones
; /* the list of zones suitable for gfp_mask */
944 if (unlikely(*z
== NULL
)) {
945 /* Should this ever happen?? */
949 page
= get_page_from_freelist(gfp_mask
|__GFP_HARDWALL
, order
,
950 zonelist
, ALLOC_WMARK_LOW
|ALLOC_CPUSET
);
955 wakeup_kswapd(*z
, order
);
959 * OK, we're below the kswapd watermark and have kicked background
960 * reclaim. Now things get more complex, so set up alloc_flags according
961 * to how we want to proceed.
963 * The caller may dip into page reserves a bit more if the caller
964 * cannot run direct reclaim, or if the caller has realtime scheduling
965 * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
966 * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
968 alloc_flags
= ALLOC_WMARK_MIN
;
969 if ((unlikely(rt_task(p
)) && !in_interrupt()) || !wait
)
970 alloc_flags
|= ALLOC_HARDER
;
971 if (gfp_mask
& __GFP_HIGH
)
972 alloc_flags
|= ALLOC_HIGH
;
974 alloc_flags
|= ALLOC_CPUSET
;
977 * Go through the zonelist again. Let __GFP_HIGH and allocations
978 * coming from realtime tasks go deeper into reserves.
980 * This is the last chance, in general, before the goto nopage.
981 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
982 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
984 page
= get_page_from_freelist(gfp_mask
, order
, zonelist
, alloc_flags
);
988 /* This allocation should allow future memory freeing. */
990 if (((p
->flags
& PF_MEMALLOC
) || unlikely(test_thread_flag(TIF_MEMDIE
)))
991 && !in_interrupt()) {
992 if (!(gfp_mask
& __GFP_NOMEMALLOC
)) {
994 /* go through the zonelist yet again, ignoring mins */
995 page
= get_page_from_freelist(gfp_mask
, order
,
996 zonelist
, ALLOC_NO_WATERMARKS
);
999 if (gfp_mask
& __GFP_NOFAIL
) {
1000 blk_congestion_wait(WRITE
, HZ
/50);
1007 /* Atomic allocations - we can't balance anything */
1014 /* We now go into synchronous reclaim */
1015 cpuset_memory_pressure_bump();
1016 p
->flags
|= PF_MEMALLOC
;
1017 reclaim_state
.reclaimed_slab
= 0;
1018 p
->reclaim_state
= &reclaim_state
;
1020 did_some_progress
= try_to_free_pages(zonelist
->zones
, gfp_mask
);
1022 p
->reclaim_state
= NULL
;
1023 p
->flags
&= ~PF_MEMALLOC
;
1027 if (likely(did_some_progress
)) {
1028 page
= get_page_from_freelist(gfp_mask
, order
,
1029 zonelist
, alloc_flags
);
1032 } else if ((gfp_mask
& __GFP_FS
) && !(gfp_mask
& __GFP_NORETRY
)) {
1034 * Go through the zonelist yet one more time, keep
1035 * very high watermark here, this is only to catch
1036 * a parallel oom killing, we must fail if we're still
1037 * under heavy pressure.
1039 page
= get_page_from_freelist(gfp_mask
|__GFP_HARDWALL
, order
,
1040 zonelist
, ALLOC_WMARK_HIGH
|ALLOC_CPUSET
);
1044 out_of_memory(zonelist
, gfp_mask
, order
);
1049 * Don't let big-order allocations loop unless the caller explicitly
1050 * requests that. Wait for some write requests to complete then retry.
1052 * In this implementation, __GFP_REPEAT means __GFP_NOFAIL for order
1053 * <= 3, but that may not be true in other implementations.
1056 if (!(gfp_mask
& __GFP_NORETRY
)) {
1057 if ((order
<= 3) || (gfp_mask
& __GFP_REPEAT
))
1059 if (gfp_mask
& __GFP_NOFAIL
)
1063 blk_congestion_wait(WRITE
, HZ
/50);
1068 if (!(gfp_mask
& __GFP_NOWARN
) && printk_ratelimit()) {
1069 printk(KERN_WARNING
"%s: page allocation failure."
1070 " order:%d, mode:0x%x\n",
1071 p
->comm
, order
, gfp_mask
);
1079 EXPORT_SYMBOL(__alloc_pages
);
1082 * Common helper functions.
1084 fastcall
unsigned long __get_free_pages(gfp_t gfp_mask
, unsigned int order
)
1087 page
= alloc_pages(gfp_mask
, order
);
1090 return (unsigned long) page_address(page
);
1093 EXPORT_SYMBOL(__get_free_pages
);
1095 fastcall
unsigned long get_zeroed_page(gfp_t gfp_mask
)
1100 * get_zeroed_page() returns a 32-bit address, which cannot represent
1103 VM_BUG_ON((gfp_mask
& __GFP_HIGHMEM
) != 0);
1105 page
= alloc_pages(gfp_mask
| __GFP_ZERO
, 0);
1107 return (unsigned long) page_address(page
);
1111 EXPORT_SYMBOL(get_zeroed_page
);
1113 void __pagevec_free(struct pagevec
*pvec
)
1115 int i
= pagevec_count(pvec
);
1118 free_hot_cold_page(pvec
->pages
[i
], pvec
->cold
);
1121 fastcall
void __free_pages(struct page
*page
, unsigned int order
)
1123 if (put_page_testzero(page
)) {
1125 free_hot_page(page
);
1127 __free_pages_ok(page
, order
);
1131 EXPORT_SYMBOL(__free_pages
);
1133 fastcall
void free_pages(unsigned long addr
, unsigned int order
)
1136 VM_BUG_ON(!virt_addr_valid((void *)addr
));
1137 __free_pages(virt_to_page((void *)addr
), order
);
1141 EXPORT_SYMBOL(free_pages
);
1144 * Total amount of free (allocatable) RAM:
1146 unsigned int nr_free_pages(void)
1148 unsigned int sum
= 0;
1152 sum
+= zone
->free_pages
;
1157 EXPORT_SYMBOL(nr_free_pages
);
1160 unsigned int nr_free_pages_pgdat(pg_data_t
*pgdat
)
1162 unsigned int sum
= 0;
1165 for (i
= 0; i
< MAX_NR_ZONES
; i
++)
1166 sum
+= pgdat
->node_zones
[i
].free_pages
;
1172 static unsigned int nr_free_zone_pages(int offset
)
1174 /* Just pick one node, since fallback list is circular */
1175 pg_data_t
*pgdat
= NODE_DATA(numa_node_id());
1176 unsigned int sum
= 0;
1178 struct zonelist
*zonelist
= pgdat
->node_zonelists
+ offset
;
1179 struct zone
**zonep
= zonelist
->zones
;
1182 for (zone
= *zonep
++; zone
; zone
= *zonep
++) {
1183 unsigned long size
= zone
->present_pages
;
1184 unsigned long high
= zone
->pages_high
;
1193 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
1195 unsigned int nr_free_buffer_pages(void)
1197 return nr_free_zone_pages(gfp_zone(GFP_USER
));
1201 * Amount of free RAM allocatable within all zones
1203 unsigned int nr_free_pagecache_pages(void)
1205 return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER
));
1208 static void show_node(struct zone
*zone
)
1210 printk("Node %d ", zone
->zone_pgdat
->node_id
);
1213 #define show_node(zone) do { } while (0)
1216 void si_meminfo(struct sysinfo
*val
)
1218 val
->totalram
= totalram_pages
;
1220 val
->freeram
= nr_free_pages();
1221 val
->bufferram
= nr_blockdev_pages();
1222 val
->totalhigh
= totalhigh_pages
;
1223 val
->freehigh
= nr_free_highpages();
1224 val
->mem_unit
= PAGE_SIZE
;
1227 EXPORT_SYMBOL(si_meminfo
);
1230 void si_meminfo_node(struct sysinfo
*val
, int nid
)
1232 pg_data_t
*pgdat
= NODE_DATA(nid
);
1234 val
->totalram
= pgdat
->node_present_pages
;
1235 val
->freeram
= nr_free_pages_pgdat(pgdat
);
1236 #ifdef CONFIG_HIGHMEM
1237 val
->totalhigh
= pgdat
->node_zones
[ZONE_HIGHMEM
].present_pages
;
1238 val
->freehigh
= pgdat
->node_zones
[ZONE_HIGHMEM
].free_pages
;
1243 val
->mem_unit
= PAGE_SIZE
;
1247 #define K(x) ((x) << (PAGE_SHIFT-10))
1250 * Show free area list (used inside shift_scroll-lock stuff)
1251 * We also calculate the percentage fragmentation. We do this by counting the
1252 * memory on each free list with the exception of the first item on the list.
1254 void show_free_areas(void)
1256 int cpu
, temperature
;
1257 unsigned long active
;
1258 unsigned long inactive
;
1262 for_each_zone(zone
) {
1264 printk("%s per-cpu:", zone
->name
);
1266 if (!populated_zone(zone
)) {
1272 for_each_online_cpu(cpu
) {
1273 struct per_cpu_pageset
*pageset
;
1275 pageset
= zone_pcp(zone
, cpu
);
1277 for (temperature
= 0; temperature
< 2; temperature
++)
1278 printk("cpu %d %s: high %d, batch %d used:%d\n",
1280 temperature
? "cold" : "hot",
1281 pageset
->pcp
[temperature
].high
,
1282 pageset
->pcp
[temperature
].batch
,
1283 pageset
->pcp
[temperature
].count
);
1287 get_zone_counts(&active
, &inactive
, &free
);
1289 printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu "
1290 "unstable:%lu free:%u slab:%lu mapped:%lu pagetables:%lu\n",
1293 global_page_state(NR_FILE_DIRTY
),
1294 global_page_state(NR_WRITEBACK
),
1295 global_page_state(NR_UNSTABLE_NFS
),
1297 global_page_state(NR_SLAB
),
1298 global_page_state(NR_FILE_MAPPED
),
1299 global_page_state(NR_PAGETABLE
));
1301 for_each_zone(zone
) {
1313 " pages_scanned:%lu"
1314 " all_unreclaimable? %s"
1317 K(zone
->free_pages
),
1320 K(zone
->pages_high
),
1322 K(zone
->nr_inactive
),
1323 K(zone
->present_pages
),
1324 zone
->pages_scanned
,
1325 (zone
->all_unreclaimable
? "yes" : "no")
1327 printk("lowmem_reserve[]:");
1328 for (i
= 0; i
< MAX_NR_ZONES
; i
++)
1329 printk(" %lu", zone
->lowmem_reserve
[i
]);
1333 for_each_zone(zone
) {
1334 unsigned long nr
[MAX_ORDER
], flags
, order
, total
= 0;
1337 printk("%s: ", zone
->name
);
1338 if (!populated_zone(zone
)) {
1343 spin_lock_irqsave(&zone
->lock
, flags
);
1344 for (order
= 0; order
< MAX_ORDER
; order
++) {
1345 nr
[order
] = zone
->free_area
[order
].nr_free
;
1346 total
+= nr
[order
] << order
;
1348 spin_unlock_irqrestore(&zone
->lock
, flags
);
1349 for (order
= 0; order
< MAX_ORDER
; order
++)
1350 printk("%lu*%lukB ", nr
[order
], K(1UL) << order
);
1351 printk("= %lukB\n", K(total
));
1354 show_swap_cache_info();
1358 * Builds allocation fallback zone lists.
1360 * Add all populated zones of a node to the zonelist.
1362 static int __meminit
build_zonelists_node(pg_data_t
*pgdat
,
1363 struct zonelist
*zonelist
, int nr_zones
, enum zone_type zone_type
)
1367 BUG_ON(zone_type
>= MAX_NR_ZONES
);
1372 zone
= pgdat
->node_zones
+ zone_type
;
1373 if (populated_zone(zone
)) {
1374 zonelist
->zones
[nr_zones
++] = zone
;
1375 check_highest_zone(zone_type
);
1378 } while (zone_type
);
1383 #define MAX_NODE_LOAD (num_online_nodes())
1384 static int __meminitdata node_load
[MAX_NUMNODES
];
1386 * find_next_best_node - find the next node that should appear in a given node's fallback list
1387 * @node: node whose fallback list we're appending
1388 * @used_node_mask: nodemask_t of already used nodes
1390 * We use a number of factors to determine which is the next node that should
1391 * appear on a given node's fallback list. The node should not have appeared
1392 * already in @node's fallback list, and it should be the next closest node
1393 * according to the distance array (which contains arbitrary distance values
1394 * from each node to each node in the system), and should also prefer nodes
1395 * with no CPUs, since presumably they'll have very little allocation pressure
1396 * on them otherwise.
1397 * It returns -1 if no node is found.
1399 static int __meminit
find_next_best_node(int node
, nodemask_t
*used_node_mask
)
1402 int min_val
= INT_MAX
;
1405 /* Use the local node if we haven't already */
1406 if (!node_isset(node
, *used_node_mask
)) {
1407 node_set(node
, *used_node_mask
);
1411 for_each_online_node(n
) {
1414 /* Don't want a node to appear more than once */
1415 if (node_isset(n
, *used_node_mask
))
1418 /* Use the distance array to find the distance */
1419 val
= node_distance(node
, n
);
1421 /* Penalize nodes under us ("prefer the next node") */
1424 /* Give preference to headless and unused nodes */
1425 tmp
= node_to_cpumask(n
);
1426 if (!cpus_empty(tmp
))
1427 val
+= PENALTY_FOR_NODE_WITH_CPUS
;
1429 /* Slight preference for less loaded node */
1430 val
*= (MAX_NODE_LOAD
*MAX_NUMNODES
);
1431 val
+= node_load
[n
];
1433 if (val
< min_val
) {
1440 node_set(best_node
, *used_node_mask
);
1445 static void __meminit
build_zonelists(pg_data_t
*pgdat
)
1447 int j
, node
, local_node
;
1449 int prev_node
, load
;
1450 struct zonelist
*zonelist
;
1451 nodemask_t used_mask
;
1453 /* initialize zonelists */
1454 for (i
= 0; i
< MAX_NR_ZONES
; i
++) {
1455 zonelist
= pgdat
->node_zonelists
+ i
;
1456 zonelist
->zones
[0] = NULL
;
1459 /* NUMA-aware ordering of nodes */
1460 local_node
= pgdat
->node_id
;
1461 load
= num_online_nodes();
1462 prev_node
= local_node
;
1463 nodes_clear(used_mask
);
1464 while ((node
= find_next_best_node(local_node
, &used_mask
)) >= 0) {
1465 int distance
= node_distance(local_node
, node
);
1468 * If another node is sufficiently far away then it is better
1469 * to reclaim pages in a zone before going off node.
1471 if (distance
> RECLAIM_DISTANCE
)
1472 zone_reclaim_mode
= 1;
1475 * We don't want to pressure a particular node.
1476 * So adding penalty to the first node in same
1477 * distance group to make it round-robin.
1480 if (distance
!= node_distance(local_node
, prev_node
))
1481 node_load
[node
] += load
;
1484 for (i
= 0; i
< MAX_NR_ZONES
; i
++) {
1485 zonelist
= pgdat
->node_zonelists
+ i
;
1486 for (j
= 0; zonelist
->zones
[j
] != NULL
; j
++);
1488 j
= build_zonelists_node(NODE_DATA(node
), zonelist
, j
, i
);
1489 zonelist
->zones
[j
] = NULL
;
1494 #else /* CONFIG_NUMA */
1496 static void __meminit
build_zonelists(pg_data_t
*pgdat
)
1498 int node
, local_node
;
1501 local_node
= pgdat
->node_id
;
1502 for (i
= 0; i
< MAX_NR_ZONES
; i
++) {
1503 struct zonelist
*zonelist
;
1505 zonelist
= pgdat
->node_zonelists
+ i
;
1507 j
= build_zonelists_node(pgdat
, zonelist
, 0, i
);
1509 * Now we build the zonelist so that it contains the zones
1510 * of all the other nodes.
1511 * We don't want to pressure a particular node, so when
1512 * building the zones for node N, we make sure that the
1513 * zones coming right after the local ones are those from
1514 * node N+1 (modulo N)
1516 for (node
= local_node
+ 1; node
< MAX_NUMNODES
; node
++) {
1517 if (!node_online(node
))
1519 j
= build_zonelists_node(NODE_DATA(node
), zonelist
, j
, i
);
1521 for (node
= 0; node
< local_node
; node
++) {
1522 if (!node_online(node
))
1524 j
= build_zonelists_node(NODE_DATA(node
), zonelist
, j
, i
);
1527 zonelist
->zones
[j
] = NULL
;
1531 #endif /* CONFIG_NUMA */
1533 /* return values int ....just for stop_machine_run() */
1534 static int __meminit
__build_all_zonelists(void *dummy
)
1537 for_each_online_node(nid
)
1538 build_zonelists(NODE_DATA(nid
));
1542 void __meminit
build_all_zonelists(void)
1544 if (system_state
== SYSTEM_BOOTING
) {
1545 __build_all_zonelists(0);
1546 cpuset_init_current_mems_allowed();
1548 /* we have to stop all cpus to guaranntee there is no user
1550 stop_machine_run(__build_all_zonelists
, NULL
, NR_CPUS
);
1551 /* cpuset refresh routine should be here */
1553 vm_total_pages
= nr_free_pagecache_pages();
1554 printk("Built %i zonelists. Total pages: %ld\n",
1555 num_online_nodes(), vm_total_pages
);
1559 * Helper functions to size the waitqueue hash table.
1560 * Essentially these want to choose hash table sizes sufficiently
1561 * large so that collisions trying to wait on pages are rare.
1562 * But in fact, the number of active page waitqueues on typical
1563 * systems is ridiculously low, less than 200. So this is even
1564 * conservative, even though it seems large.
1566 * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
1567 * waitqueues, i.e. the size of the waitq table given the number of pages.
1569 #define PAGES_PER_WAITQUEUE 256
1571 #ifndef CONFIG_MEMORY_HOTPLUG
1572 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages
)
1574 unsigned long size
= 1;
1576 pages
/= PAGES_PER_WAITQUEUE
;
1578 while (size
< pages
)
1582 * Once we have dozens or even hundreds of threads sleeping
1583 * on IO we've got bigger problems than wait queue collision.
1584 * Limit the size of the wait table to a reasonable size.
1586 size
= min(size
, 4096UL);
1588 return max(size
, 4UL);
1592 * A zone's size might be changed by hot-add, so it is not possible to determine
1593 * a suitable size for its wait_table. So we use the maximum size now.
1595 * The max wait table size = 4096 x sizeof(wait_queue_head_t). ie:
1597 * i386 (preemption config) : 4096 x 16 = 64Kbyte.
1598 * ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
1599 * ia64, x86-64 (preemption) : 4096 x 24 = 96Kbyte.
1601 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
1602 * or more by the traditional way. (See above). It equals:
1604 * i386, x86-64, powerpc(4K page size) : = ( 2G + 1M)byte.
1605 * ia64(16K page size) : = ( 8G + 4M)byte.
1606 * powerpc (64K page size) : = (32G +16M)byte.
1608 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages
)
1615 * This is an integer logarithm so that shifts can be used later
1616 * to extract the more random high bits from the multiplicative
1617 * hash function before the remainder is taken.
1619 static inline unsigned long wait_table_bits(unsigned long size
)
1624 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
1626 static void __init
calculate_zone_totalpages(struct pglist_data
*pgdat
,
1627 unsigned long *zones_size
, unsigned long *zholes_size
)
1629 unsigned long realtotalpages
, totalpages
= 0;
1632 for (i
= 0; i
< MAX_NR_ZONES
; i
++)
1633 totalpages
+= zones_size
[i
];
1634 pgdat
->node_spanned_pages
= totalpages
;
1636 realtotalpages
= totalpages
;
1638 for (i
= 0; i
< MAX_NR_ZONES
; i
++)
1639 realtotalpages
-= zholes_size
[i
];
1640 pgdat
->node_present_pages
= realtotalpages
;
1641 printk(KERN_DEBUG
"On node %d totalpages: %lu\n", pgdat
->node_id
, realtotalpages
);
1646 * Initially all pages are reserved - free ones are freed
1647 * up by free_all_bootmem() once the early boot process is
1648 * done. Non-atomic initialization, single-pass.
1650 void __meminit
memmap_init_zone(unsigned long size
, int nid
, unsigned long zone
,
1651 unsigned long start_pfn
)
1654 unsigned long end_pfn
= start_pfn
+ size
;
1657 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
++) {
1658 if (!early_pfn_valid(pfn
))
1660 page
= pfn_to_page(pfn
);
1661 set_page_links(page
, zone
, nid
, pfn
);
1662 init_page_count(page
);
1663 reset_page_mapcount(page
);
1664 SetPageReserved(page
);
1665 INIT_LIST_HEAD(&page
->lru
);
1666 #ifdef WANT_PAGE_VIRTUAL
1667 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
1668 if (!is_highmem_idx(zone
))
1669 set_page_address(page
, __va(pfn
<< PAGE_SHIFT
));
1674 void zone_init_free_lists(struct pglist_data
*pgdat
, struct zone
*zone
,
1678 for (order
= 0; order
< MAX_ORDER
; order
++) {
1679 INIT_LIST_HEAD(&zone
->free_area
[order
].free_list
);
1680 zone
->free_area
[order
].nr_free
= 0;
1684 #define ZONETABLE_INDEX(x, zone_nr) ((x << ZONES_SHIFT) | zone_nr)
1685 void zonetable_add(struct zone
*zone
, int nid
, enum zone_type zid
,
1686 unsigned long pfn
, unsigned long size
)
1688 unsigned long snum
= pfn_to_section_nr(pfn
);
1689 unsigned long end
= pfn_to_section_nr(pfn
+ size
);
1692 zone_table
[ZONETABLE_INDEX(nid
, zid
)] = zone
;
1694 for (; snum
<= end
; snum
++)
1695 zone_table
[ZONETABLE_INDEX(snum
, zid
)] = zone
;
1698 #ifndef __HAVE_ARCH_MEMMAP_INIT
1699 #define memmap_init(size, nid, zone, start_pfn) \
1700 memmap_init_zone((size), (nid), (zone), (start_pfn))
1703 static int __cpuinit
zone_batchsize(struct zone
*zone
)
1708 * The per-cpu-pages pools are set to around 1000th of the
1709 * size of the zone. But no more than 1/2 of a meg.
1711 * OK, so we don't know how big the cache is. So guess.
1713 batch
= zone
->present_pages
/ 1024;
1714 if (batch
* PAGE_SIZE
> 512 * 1024)
1715 batch
= (512 * 1024) / PAGE_SIZE
;
1716 batch
/= 4; /* We effectively *= 4 below */
1721 * Clamp the batch to a 2^n - 1 value. Having a power
1722 * of 2 value was found to be more likely to have
1723 * suboptimal cache aliasing properties in some cases.
1725 * For example if 2 tasks are alternately allocating
1726 * batches of pages, one task can end up with a lot
1727 * of pages of one half of the possible page colors
1728 * and the other with pages of the other colors.
1730 batch
= (1 << (fls(batch
+ batch
/2)-1)) - 1;
1735 inline void setup_pageset(struct per_cpu_pageset
*p
, unsigned long batch
)
1737 struct per_cpu_pages
*pcp
;
1739 memset(p
, 0, sizeof(*p
));
1741 pcp
= &p
->pcp
[0]; /* hot */
1743 pcp
->high
= 6 * batch
;
1744 pcp
->batch
= max(1UL, 1 * batch
);
1745 INIT_LIST_HEAD(&pcp
->list
);
1747 pcp
= &p
->pcp
[1]; /* cold*/
1749 pcp
->high
= 2 * batch
;
1750 pcp
->batch
= max(1UL, batch
/2);
1751 INIT_LIST_HEAD(&pcp
->list
);
1755 * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
1756 * to the value high for the pageset p.
1759 static void setup_pagelist_highmark(struct per_cpu_pageset
*p
,
1762 struct per_cpu_pages
*pcp
;
1764 pcp
= &p
->pcp
[0]; /* hot list */
1766 pcp
->batch
= max(1UL, high
/4);
1767 if ((high
/4) > (PAGE_SHIFT
* 8))
1768 pcp
->batch
= PAGE_SHIFT
* 8;
1774 * Boot pageset table. One per cpu which is going to be used for all
1775 * zones and all nodes. The parameters will be set in such a way
1776 * that an item put on a list will immediately be handed over to
1777 * the buddy list. This is safe since pageset manipulation is done
1778 * with interrupts disabled.
1780 * Some NUMA counter updates may also be caught by the boot pagesets.
1782 * The boot_pagesets must be kept even after bootup is complete for
1783 * unused processors and/or zones. They do play a role for bootstrapping
1784 * hotplugged processors.
1786 * zoneinfo_show() and maybe other functions do
1787 * not check if the processor is online before following the pageset pointer.
1788 * Other parts of the kernel may not check if the zone is available.
1790 static struct per_cpu_pageset boot_pageset
[NR_CPUS
];
1793 * Dynamically allocate memory for the
1794 * per cpu pageset array in struct zone.
1796 static int __cpuinit
process_zones(int cpu
)
1798 struct zone
*zone
, *dzone
;
1800 for_each_zone(zone
) {
1802 zone_pcp(zone
, cpu
) = kmalloc_node(sizeof(struct per_cpu_pageset
),
1803 GFP_KERNEL
, cpu_to_node(cpu
));
1804 if (!zone_pcp(zone
, cpu
))
1807 setup_pageset(zone_pcp(zone
, cpu
), zone_batchsize(zone
));
1809 if (percpu_pagelist_fraction
)
1810 setup_pagelist_highmark(zone_pcp(zone
, cpu
),
1811 (zone
->present_pages
/ percpu_pagelist_fraction
));
1816 for_each_zone(dzone
) {
1819 kfree(zone_pcp(dzone
, cpu
));
1820 zone_pcp(dzone
, cpu
) = NULL
;
1825 static inline void free_zone_pagesets(int cpu
)
1829 for_each_zone(zone
) {
1830 struct per_cpu_pageset
*pset
= zone_pcp(zone
, cpu
);
1832 /* Free per_cpu_pageset if it is slab allocated */
1833 if (pset
!= &boot_pageset
[cpu
])
1835 zone_pcp(zone
, cpu
) = NULL
;
1839 static int __cpuinit
pageset_cpuup_callback(struct notifier_block
*nfb
,
1840 unsigned long action
,
1843 int cpu
= (long)hcpu
;
1844 int ret
= NOTIFY_OK
;
1847 case CPU_UP_PREPARE
:
1848 if (process_zones(cpu
))
1851 case CPU_UP_CANCELED
:
1853 free_zone_pagesets(cpu
);
1861 static struct notifier_block __cpuinitdata pageset_notifier
=
1862 { &pageset_cpuup_callback
, NULL
, 0 };
1864 void __init
setup_per_cpu_pageset(void)
1868 /* Initialize per_cpu_pageset for cpu 0.
1869 * A cpuup callback will do this for every cpu
1870 * as it comes online
1872 err
= process_zones(smp_processor_id());
1874 register_cpu_notifier(&pageset_notifier
);
1880 int zone_wait_table_init(struct zone
*zone
, unsigned long zone_size_pages
)
1883 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
1887 * The per-page waitqueue mechanism uses hashed waitqueues
1890 zone
->wait_table_hash_nr_entries
=
1891 wait_table_hash_nr_entries(zone_size_pages
);
1892 zone
->wait_table_bits
=
1893 wait_table_bits(zone
->wait_table_hash_nr_entries
);
1894 alloc_size
= zone
->wait_table_hash_nr_entries
1895 * sizeof(wait_queue_head_t
);
1897 if (system_state
== SYSTEM_BOOTING
) {
1898 zone
->wait_table
= (wait_queue_head_t
*)
1899 alloc_bootmem_node(pgdat
, alloc_size
);
1902 * This case means that a zone whose size was 0 gets new memory
1903 * via memory hot-add.
1904 * But it may be the case that a new node was hot-added. In
1905 * this case vmalloc() will not be able to use this new node's
1906 * memory - this wait_table must be initialized to use this new
1907 * node itself as well.
1908 * To use this new node's memory, further consideration will be
1911 zone
->wait_table
= (wait_queue_head_t
*)vmalloc(alloc_size
);
1913 if (!zone
->wait_table
)
1916 for(i
= 0; i
< zone
->wait_table_hash_nr_entries
; ++i
)
1917 init_waitqueue_head(zone
->wait_table
+ i
);
1922 static __meminit
void zone_pcp_init(struct zone
*zone
)
1925 unsigned long batch
= zone_batchsize(zone
);
1927 for (cpu
= 0; cpu
< NR_CPUS
; cpu
++) {
1929 /* Early boot. Slab allocator not functional yet */
1930 zone_pcp(zone
, cpu
) = &boot_pageset
[cpu
];
1931 setup_pageset(&boot_pageset
[cpu
],0);
1933 setup_pageset(zone_pcp(zone
,cpu
), batch
);
1936 if (zone
->present_pages
)
1937 printk(KERN_DEBUG
" %s zone: %lu pages, LIFO batch:%lu\n",
1938 zone
->name
, zone
->present_pages
, batch
);
1941 __meminit
int init_currently_empty_zone(struct zone
*zone
,
1942 unsigned long zone_start_pfn
,
1945 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
1947 ret
= zone_wait_table_init(zone
, size
);
1950 pgdat
->nr_zones
= zone_idx(zone
) + 1;
1952 zone
->zone_start_pfn
= zone_start_pfn
;
1954 memmap_init(size
, pgdat
->node_id
, zone_idx(zone
), zone_start_pfn
);
1956 zone_init_free_lists(pgdat
, zone
, zone
->spanned_pages
);
1962 * Set up the zone data structures:
1963 * - mark all pages reserved
1964 * - mark all memory queues empty
1965 * - clear the memory bitmaps
1967 static void __meminit
free_area_init_core(struct pglist_data
*pgdat
,
1968 unsigned long *zones_size
, unsigned long *zholes_size
)
1971 int nid
= pgdat
->node_id
;
1972 unsigned long zone_start_pfn
= pgdat
->node_start_pfn
;
1975 pgdat_resize_init(pgdat
);
1976 pgdat
->nr_zones
= 0;
1977 init_waitqueue_head(&pgdat
->kswapd_wait
);
1978 pgdat
->kswapd_max_order
= 0;
1980 for (j
= 0; j
< MAX_NR_ZONES
; j
++) {
1981 struct zone
*zone
= pgdat
->node_zones
+ j
;
1982 unsigned long size
, realsize
;
1984 realsize
= size
= zones_size
[j
];
1986 realsize
-= zholes_size
[j
];
1988 if (!is_highmem_idx(j
))
1989 nr_kernel_pages
+= realsize
;
1990 nr_all_pages
+= realsize
;
1992 zone
->spanned_pages
= size
;
1993 zone
->present_pages
= realsize
;
1995 zone
->min_unmapped_ratio
= (realsize
*sysctl_min_unmapped_ratio
)
1998 zone
->name
= zone_names
[j
];
1999 spin_lock_init(&zone
->lock
);
2000 spin_lock_init(&zone
->lru_lock
);
2001 zone_seqlock_init(zone
);
2002 zone
->zone_pgdat
= pgdat
;
2003 zone
->free_pages
= 0;
2005 zone
->temp_priority
= zone
->prev_priority
= DEF_PRIORITY
;
2007 zone_pcp_init(zone
);
2008 INIT_LIST_HEAD(&zone
->active_list
);
2009 INIT_LIST_HEAD(&zone
->inactive_list
);
2010 zone
->nr_scan_active
= 0;
2011 zone
->nr_scan_inactive
= 0;
2012 zone
->nr_active
= 0;
2013 zone
->nr_inactive
= 0;
2014 zap_zone_vm_stats(zone
);
2015 atomic_set(&zone
->reclaim_in_progress
, 0);
2019 zonetable_add(zone
, nid
, j
, zone_start_pfn
, size
);
2020 ret
= init_currently_empty_zone(zone
, zone_start_pfn
, size
);
2022 zone_start_pfn
+= size
;
2026 static void __init
alloc_node_mem_map(struct pglist_data
*pgdat
)
2028 /* Skip empty nodes */
2029 if (!pgdat
->node_spanned_pages
)
2032 #ifdef CONFIG_FLAT_NODE_MEM_MAP
2033 /* ia64 gets its own node_mem_map, before this, without bootmem */
2034 if (!pgdat
->node_mem_map
) {
2035 unsigned long size
, start
, end
;
2039 * The zone's endpoints aren't required to be MAX_ORDER
2040 * aligned but the node_mem_map endpoints must be in order
2041 * for the buddy allocator to function correctly.
2043 start
= pgdat
->node_start_pfn
& ~(MAX_ORDER_NR_PAGES
- 1);
2044 end
= pgdat
->node_start_pfn
+ pgdat
->node_spanned_pages
;
2045 end
= ALIGN(end
, MAX_ORDER_NR_PAGES
);
2046 size
= (end
- start
) * sizeof(struct page
);
2047 map
= alloc_remap(pgdat
->node_id
, size
);
2049 map
= alloc_bootmem_node(pgdat
, size
);
2050 pgdat
->node_mem_map
= map
+ (pgdat
->node_start_pfn
- start
);
2052 #ifdef CONFIG_FLATMEM
2054 * With no DISCONTIG, the global mem_map is just set as node 0's
2056 if (pgdat
== NODE_DATA(0))
2057 mem_map
= NODE_DATA(0)->node_mem_map
;
2059 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
2062 void __meminit
free_area_init_node(int nid
, struct pglist_data
*pgdat
,
2063 unsigned long *zones_size
, unsigned long node_start_pfn
,
2064 unsigned long *zholes_size
)
2066 pgdat
->node_id
= nid
;
2067 pgdat
->node_start_pfn
= node_start_pfn
;
2068 calculate_zone_totalpages(pgdat
, zones_size
, zholes_size
);
2070 alloc_node_mem_map(pgdat
);
2072 free_area_init_core(pgdat
, zones_size
, zholes_size
);
2075 #ifndef CONFIG_NEED_MULTIPLE_NODES
2076 static bootmem_data_t contig_bootmem_data
;
2077 struct pglist_data contig_page_data
= { .bdata
= &contig_bootmem_data
};
2079 EXPORT_SYMBOL(contig_page_data
);
2082 void __init
free_area_init(unsigned long *zones_size
)
2084 free_area_init_node(0, NODE_DATA(0), zones_size
,
2085 __pa(PAGE_OFFSET
) >> PAGE_SHIFT
, NULL
);
2088 #ifdef CONFIG_HOTPLUG_CPU
2089 static int page_alloc_cpu_notify(struct notifier_block
*self
,
2090 unsigned long action
, void *hcpu
)
2092 int cpu
= (unsigned long)hcpu
;
2094 if (action
== CPU_DEAD
) {
2095 local_irq_disable();
2097 vm_events_fold_cpu(cpu
);
2099 refresh_cpu_vm_stats(cpu
);
2103 #endif /* CONFIG_HOTPLUG_CPU */
2105 void __init
page_alloc_init(void)
2107 hotcpu_notifier(page_alloc_cpu_notify
, 0);
2111 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
2112 * or min_free_kbytes changes.
2114 static void calculate_totalreserve_pages(void)
2116 struct pglist_data
*pgdat
;
2117 unsigned long reserve_pages
= 0;
2118 enum zone_type i
, j
;
2120 for_each_online_pgdat(pgdat
) {
2121 for (i
= 0; i
< MAX_NR_ZONES
; i
++) {
2122 struct zone
*zone
= pgdat
->node_zones
+ i
;
2123 unsigned long max
= 0;
2125 /* Find valid and maximum lowmem_reserve in the zone */
2126 for (j
= i
; j
< MAX_NR_ZONES
; j
++) {
2127 if (zone
->lowmem_reserve
[j
] > max
)
2128 max
= zone
->lowmem_reserve
[j
];
2131 /* we treat pages_high as reserved pages. */
2132 max
+= zone
->pages_high
;
2134 if (max
> zone
->present_pages
)
2135 max
= zone
->present_pages
;
2136 reserve_pages
+= max
;
2139 totalreserve_pages
= reserve_pages
;
2143 * setup_per_zone_lowmem_reserve - called whenever
2144 * sysctl_lower_zone_reserve_ratio changes. Ensures that each zone
2145 * has a correct pages reserved value, so an adequate number of
2146 * pages are left in the zone after a successful __alloc_pages().
2148 static void setup_per_zone_lowmem_reserve(void)
2150 struct pglist_data
*pgdat
;
2151 enum zone_type j
, idx
;
2153 for_each_online_pgdat(pgdat
) {
2154 for (j
= 0; j
< MAX_NR_ZONES
; j
++) {
2155 struct zone
*zone
= pgdat
->node_zones
+ j
;
2156 unsigned long present_pages
= zone
->present_pages
;
2158 zone
->lowmem_reserve
[j
] = 0;
2162 struct zone
*lower_zone
;
2166 if (sysctl_lowmem_reserve_ratio
[idx
] < 1)
2167 sysctl_lowmem_reserve_ratio
[idx
] = 1;
2169 lower_zone
= pgdat
->node_zones
+ idx
;
2170 lower_zone
->lowmem_reserve
[j
] = present_pages
/
2171 sysctl_lowmem_reserve_ratio
[idx
];
2172 present_pages
+= lower_zone
->present_pages
;
2177 /* update totalreserve_pages */
2178 calculate_totalreserve_pages();
2182 * setup_per_zone_pages_min - called when min_free_kbytes changes. Ensures
2183 * that the pages_{min,low,high} values for each zone are set correctly
2184 * with respect to min_free_kbytes.
2186 void setup_per_zone_pages_min(void)
2188 unsigned long pages_min
= min_free_kbytes
>> (PAGE_SHIFT
- 10);
2189 unsigned long lowmem_pages
= 0;
2191 unsigned long flags
;
2193 /* Calculate total number of !ZONE_HIGHMEM pages */
2194 for_each_zone(zone
) {
2195 if (!is_highmem(zone
))
2196 lowmem_pages
+= zone
->present_pages
;
2199 for_each_zone(zone
) {
2202 spin_lock_irqsave(&zone
->lru_lock
, flags
);
2203 tmp
= (u64
)pages_min
* zone
->present_pages
;
2204 do_div(tmp
, lowmem_pages
);
2205 if (is_highmem(zone
)) {
2207 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
2208 * need highmem pages, so cap pages_min to a small
2211 * The (pages_high-pages_low) and (pages_low-pages_min)
2212 * deltas controls asynch page reclaim, and so should
2213 * not be capped for highmem.
2217 min_pages
= zone
->present_pages
/ 1024;
2218 if (min_pages
< SWAP_CLUSTER_MAX
)
2219 min_pages
= SWAP_CLUSTER_MAX
;
2220 if (min_pages
> 128)
2222 zone
->pages_min
= min_pages
;
2225 * If it's a lowmem zone, reserve a number of pages
2226 * proportionate to the zone's size.
2228 zone
->pages_min
= tmp
;
2231 zone
->pages_low
= zone
->pages_min
+ (tmp
>> 2);
2232 zone
->pages_high
= zone
->pages_min
+ (tmp
>> 1);
2233 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
2236 /* update totalreserve_pages */
2237 calculate_totalreserve_pages();
2241 * Initialise min_free_kbytes.
2243 * For small machines we want it small (128k min). For large machines
2244 * we want it large (64MB max). But it is not linear, because network
2245 * bandwidth does not increase linearly with machine size. We use
2247 * min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
2248 * min_free_kbytes = sqrt(lowmem_kbytes * 16)
2264 static int __init
init_per_zone_pages_min(void)
2266 unsigned long lowmem_kbytes
;
2268 lowmem_kbytes
= nr_free_buffer_pages() * (PAGE_SIZE
>> 10);
2270 min_free_kbytes
= int_sqrt(lowmem_kbytes
* 16);
2271 if (min_free_kbytes
< 128)
2272 min_free_kbytes
= 128;
2273 if (min_free_kbytes
> 65536)
2274 min_free_kbytes
= 65536;
2275 setup_per_zone_pages_min();
2276 setup_per_zone_lowmem_reserve();
2279 module_init(init_per_zone_pages_min
)
2282 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
2283 * that we can call two helper functions whenever min_free_kbytes
2286 int min_free_kbytes_sysctl_handler(ctl_table
*table
, int write
,
2287 struct file
*file
, void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2289 proc_dointvec(table
, write
, file
, buffer
, length
, ppos
);
2290 setup_per_zone_pages_min();
2295 int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table
*table
, int write
,
2296 struct file
*file
, void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2301 rc
= proc_dointvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
2306 zone
->min_unmapped_ratio
= (zone
->present_pages
*
2307 sysctl_min_unmapped_ratio
) / 100;
2313 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
2314 * proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
2315 * whenever sysctl_lowmem_reserve_ratio changes.
2317 * The reserve ratio obviously has absolutely no relation with the
2318 * pages_min watermarks. The lowmem reserve ratio can only make sense
2319 * if in function of the boot time zone sizes.
2321 int lowmem_reserve_ratio_sysctl_handler(ctl_table
*table
, int write
,
2322 struct file
*file
, void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2324 proc_dointvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
2325 setup_per_zone_lowmem_reserve();
2330 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
2331 * cpu. It is the fraction of total pages in each zone that a hot per cpu pagelist
2332 * can have before it gets flushed back to buddy allocator.
2335 int percpu_pagelist_fraction_sysctl_handler(ctl_table
*table
, int write
,
2336 struct file
*file
, void __user
*buffer
, size_t *length
, loff_t
*ppos
)
2342 ret
= proc_dointvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
2343 if (!write
|| (ret
== -EINVAL
))
2345 for_each_zone(zone
) {
2346 for_each_online_cpu(cpu
) {
2348 high
= zone
->present_pages
/ percpu_pagelist_fraction
;
2349 setup_pagelist_highmark(zone_pcp(zone
, cpu
), high
);
2355 int hashdist
= HASHDIST_DEFAULT
;
2358 static int __init
set_hashdist(char *str
)
2362 hashdist
= simple_strtoul(str
, &str
, 0);
2365 __setup("hashdist=", set_hashdist
);
2369 * allocate a large system hash table from bootmem
2370 * - it is assumed that the hash table must contain an exact power-of-2
2371 * quantity of entries
2372 * - limit is the number of hash buckets, not the total allocation size
2374 void *__init
alloc_large_system_hash(const char *tablename
,
2375 unsigned long bucketsize
,
2376 unsigned long numentries
,
2379 unsigned int *_hash_shift
,
2380 unsigned int *_hash_mask
,
2381 unsigned long limit
)
2383 unsigned long long max
= limit
;
2384 unsigned long log2qty
, size
;
2387 /* allow the kernel cmdline to have a say */
2389 /* round applicable memory size up to nearest megabyte */
2390 numentries
= (flags
& HASH_HIGHMEM
) ? nr_all_pages
: nr_kernel_pages
;
2391 numentries
+= (1UL << (20 - PAGE_SHIFT
)) - 1;
2392 numentries
>>= 20 - PAGE_SHIFT
;
2393 numentries
<<= 20 - PAGE_SHIFT
;
2395 /* limit to 1 bucket per 2^scale bytes of low memory */
2396 if (scale
> PAGE_SHIFT
)
2397 numentries
>>= (scale
- PAGE_SHIFT
);
2399 numentries
<<= (PAGE_SHIFT
- scale
);
2401 numentries
= roundup_pow_of_two(numentries
);
2403 /* limit allocation size to 1/16 total memory by default */
2405 max
= ((unsigned long long)nr_all_pages
<< PAGE_SHIFT
) >> 4;
2406 do_div(max
, bucketsize
);
2409 if (numentries
> max
)
2412 log2qty
= long_log2(numentries
);
2415 size
= bucketsize
<< log2qty
;
2416 if (flags
& HASH_EARLY
)
2417 table
= alloc_bootmem(size
);
2419 table
= __vmalloc(size
, GFP_ATOMIC
, PAGE_KERNEL
);
2421 unsigned long order
;
2422 for (order
= 0; ((1UL << order
) << PAGE_SHIFT
) < size
; order
++)
2424 table
= (void*) __get_free_pages(GFP_ATOMIC
, order
);
2426 } while (!table
&& size
> PAGE_SIZE
&& --log2qty
);
2429 panic("Failed to allocate %s hash table\n", tablename
);
2431 printk("%s hash table entries: %d (order: %d, %lu bytes)\n",
2434 long_log2(size
) - PAGE_SHIFT
,
2438 *_hash_shift
= log2qty
;
2440 *_hash_mask
= (1 << log2qty
) - 1;
2445 #ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
2446 struct page
*pfn_to_page(unsigned long pfn
)
2448 return __pfn_to_page(pfn
);
2450 unsigned long page_to_pfn(struct page
*page
)
2452 return __page_to_pfn(page
);
2454 EXPORT_SYMBOL(pfn_to_page
);
2455 EXPORT_SYMBOL(page_to_pfn
);
2456 #endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */