page_alloc.c 123 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
/*
 *  linux/mm/page_alloc.c
 *
 *  Manages the free list, the system allocates free pages here.
 *  Note that kmalloc() lives in slab.c
 *
 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *  Swap reorganised 29.12.95, Stephen Tweedie
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
 *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
 *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
 *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
 *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
 */

#include <linux/stddef.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/compiler.h>
24
#include <linux/kernel.h>
Linus Torvalds's avatar
Linus Torvalds committed
25
26
27
28
29
#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/pagevec.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
30
#include <linux/oom.h>
Linus Torvalds's avatar
Linus Torvalds committed
31
32
33
34
35
#include <linux/notifier.h>
#include <linux/topology.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
36
#include <linux/memory_hotplug.h>
Linus Torvalds's avatar
Linus Torvalds committed
37
38
#include <linux/nodemask.h>
#include <linux/vmalloc.h>
39
#include <linux/mempolicy.h>
40
#include <linux/stop_machine.h>
41
42
#include <linux/sort.h>
#include <linux/pfn.h>
43
#include <linux/backing-dev.h>
44
#include <linux/fault-inject.h>
45
#include <linux/page-isolation.h>
Linus Torvalds's avatar
Linus Torvalds committed
46
47

#include <asm/tlbflush.h>
48
#include <asm/div64.h>
Linus Torvalds's avatar
Linus Torvalds committed
49
50
51
#include "internal.h"

/*
52
 * Array of node states.
Linus Torvalds's avatar
Linus Torvalds committed
53
 */
54
55
56
57
58
59
60
61
62
63
64
65
66
nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
	[N_POSSIBLE] = NODE_MASK_ALL,
	[N_ONLINE] = { { [0] = 1UL } },
#ifndef CONFIG_NUMA
	[N_NORMAL_MEMORY] = { { [0] = 1UL } },
#ifdef CONFIG_HIGHMEM
	[N_HIGH_MEMORY] = { { [0] = 1UL } },
#endif
	[N_CPU] = { { [0] = 1UL } },
#endif	/* NUMA */
};
EXPORT_SYMBOL(node_states);

67
unsigned long totalram_pages __read_mostly;
68
unsigned long totalreserve_pages __read_mostly;
Linus Torvalds's avatar
Linus Torvalds committed
69
long nr_swap_pages;
70
int percpu_pagelist_fraction;
Linus Torvalds's avatar
Linus Torvalds committed
71

72
73
74
75
#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
int pageblock_order __read_mostly;
#endif

76
static void __free_pages_ok(struct page *page, unsigned int order);
77

Linus Torvalds's avatar
Linus Torvalds committed
78
79
80
81
82
83
84
/*
 * results with 256, 32 in the lowmem_reserve sysctl:
 *	1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
 *	1G machine -> (16M dma, 784M normal, 224M high)
 *	NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
 *	HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
 *	HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
85
86
87
 *
 * TBD: should special case ZONE_DMA32 machines here - in those we normally
 * don't need any ZONE_NORMAL reservation
Linus Torvalds's avatar
Linus Torvalds committed
88
 */
89
int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
90
#ifdef CONFIG_ZONE_DMA
91
	 256,
92
#endif
93
#ifdef CONFIG_ZONE_DMA32
94
	 256,
95
#endif
96
#ifdef CONFIG_HIGHMEM
Mel Gorman's avatar
Mel Gorman committed
97
	 32,
98
#endif
Mel Gorman's avatar
Mel Gorman committed
99
	 32,
100
};
Linus Torvalds's avatar
Linus Torvalds committed
101
102
103

EXPORT_SYMBOL(totalram_pages);

104
static char * const zone_names[MAX_NR_ZONES] = {
105
#ifdef CONFIG_ZONE_DMA
106
	 "DMA",
107
#endif
108
#ifdef CONFIG_ZONE_DMA32
109
	 "DMA32",
110
#endif
111
	 "Normal",
112
#ifdef CONFIG_HIGHMEM
Mel Gorman's avatar
Mel Gorman committed
113
	 "HighMem",
114
#endif
Mel Gorman's avatar
Mel Gorman committed
115
	 "Movable",
116
117
};

Linus Torvalds's avatar
Linus Torvalds committed
118
119
int min_free_kbytes = 1024;

120
121
unsigned long __meminitdata nr_kernel_pages;
unsigned long __meminitdata nr_all_pages;
122
static unsigned long __meminitdata dma_reserve;
Linus Torvalds's avatar
Linus Torvalds committed
123

124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
  /*
   * MAX_ACTIVE_REGIONS determines the maxmimum number of distinct
   * ranges of memory (RAM) that may be registered with add_active_range().
   * Ranges passed to add_active_range() will be merged if possible
   * so the number of times add_active_range() can be called is
   * related to the number of nodes and the number of holes
   */
  #ifdef CONFIG_MAX_ACTIVE_REGIONS
    /* Allow an architecture to set MAX_ACTIVE_REGIONS to save memory */
    #define MAX_ACTIVE_REGIONS CONFIG_MAX_ACTIVE_REGIONS
  #else
    #if MAX_NUMNODES >= 32
      /* If there can be many nodes, allow up to 50 holes per node */
      #define MAX_ACTIVE_REGIONS (MAX_NUMNODES*50)
    #else
      /* By default, allow up to 256 distinct regions */
      #define MAX_ACTIVE_REGIONS 256
    #endif
  #endif

145
146
147
148
  static struct node_active_region __meminitdata early_node_map[MAX_ACTIVE_REGIONS];
  static int __meminitdata nr_nodemap_entries;
  static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
  static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
149
#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
150
151
  static unsigned long __meminitdata node_boundary_start_pfn[MAX_NUMNODES];
  static unsigned long __meminitdata node_boundary_end_pfn[MAX_NUMNODES];
152
#endif /* CONFIG_MEMORY_HOTPLUG_RESERVE */
Mel Gorman's avatar
Mel Gorman committed
153
  unsigned long __initdata required_kernelcore;
154
  static unsigned long __initdata required_movablecore;
155
  unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
Mel Gorman's avatar
Mel Gorman committed
156
157
158
159

  /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
  int movable_zone;
  EXPORT_SYMBOL(movable_zone);
160
161
#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */

Miklos Szeredi's avatar
Miklos Szeredi committed
162
163
164
165
166
#if MAX_NUMNODES > 1
int nr_node_ids __read_mostly = MAX_NUMNODES;
EXPORT_SYMBOL(nr_node_ids);
#endif

167
168
int page_group_by_mobility_disabled __read_mostly;

169
170
171
172
173
174
static void set_pageblock_migratetype(struct page *page, int migratetype)
{
	set_pageblock_flags_group(page, (unsigned long)migratetype,
					PB_migrate, PB_migrate_end);
}

Nick Piggin's avatar
Nick Piggin committed
175
#ifdef CONFIG_DEBUG_VM
176
static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
177
{
178
179
180
	int ret = 0;
	unsigned seq;
	unsigned long pfn = page_to_pfn(page);
181

182
183
184
185
186
187
188
189
190
	do {
		seq = zone_span_seqbegin(zone);
		if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
			ret = 1;
		else if (pfn < zone->zone_start_pfn)
			ret = 1;
	} while (zone_span_seqretry(zone, seq));

	return ret;
191
192
193
194
}

static int page_is_consistent(struct zone *zone, struct page *page)
{
195
	if (!pfn_valid_within(page_to_pfn(page)))
196
		return 0;
Linus Torvalds's avatar
Linus Torvalds committed
197
	if (zone != page_zone(page))
198
199
200
201
202
203
204
205
206
207
		return 0;

	return 1;
}
/*
 * Temporary debugging check for pages not lying within a given zone.
 */
static int bad_range(struct zone *zone, struct page *page)
{
	if (page_outside_zone_boundaries(zone, page))
Linus Torvalds's avatar
Linus Torvalds committed
208
		return 1;
209
210
211
	if (!page_is_consistent(zone, page))
		return 1;

Linus Torvalds's avatar
Linus Torvalds committed
212
213
	return 0;
}
Nick Piggin's avatar
Nick Piggin committed
214
215
216
217
218
219
220
#else
static inline int bad_range(struct zone *zone, struct page *page)
{
	return 0;
}
#endif

221
static void bad_page(struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
222
{
223
	printk(KERN_EMERG "Bad page state in process '%s'\n"
224
225
226
		KERN_EMERG "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n"
		KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
		KERN_EMERG "Backtrace:\n",
227
228
229
		current->comm, page, (int)(2*sizeof(unsigned long)),
		(unsigned long)page->flags, page->mapping,
		page_mapcount(page), page_count(page));
Linus Torvalds's avatar
Linus Torvalds committed
230
	dump_stack();
231
232
	page->flags &= ~(1 << PG_lru	|
			1 << PG_private |
Linus Torvalds's avatar
Linus Torvalds committed
233
234
235
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_dirty	|
236
237
			1 << PG_reclaim |
			1 << PG_slab    |
Linus Torvalds's avatar
Linus Torvalds committed
238
			1 << PG_swapcache |
239
240
			1 << PG_writeback |
			1 << PG_buddy );
Linus Torvalds's avatar
Linus Torvalds committed
241
242
243
	set_page_count(page, 0);
	reset_page_mapcount(page);
	page->mapping = NULL;
244
	add_taint(TAINT_BAD_PAGE);
Linus Torvalds's avatar
Linus Torvalds committed
245
246
247
248
249
250
251
252
253
254
255
256
}

/*
 * Higher-order pages are called "compound pages".  They are structured thusly:
 *
 * The first PAGE_SIZE page is called the "head page".
 *
 * The remaining PAGE_SIZE pages are called "tail pages".
 *
 * All pages have PG_compound set.  All pages have their ->private pointing at
 * the head page (even the head page has this).
 *
257
258
259
 * The first tail page's ->lru.next holds the address of the compound page's
 * put_page() function.  Its ->lru.prev holds the order of allocation.
 * This usage means that zero-order pages may not be compound.
Linus Torvalds's avatar
Linus Torvalds committed
260
 */
261
262
263

static void free_compound_page(struct page *page)
{
264
	__free_pages_ok(page, compound_order(page));
265
266
}

Linus Torvalds's avatar
Linus Torvalds committed
267
268
269
270
271
static void prep_compound_page(struct page *page, unsigned long order)
{
	int i;
	int nr_pages = 1 << order;

272
	set_compound_page_dtor(page, free_compound_page);
273
	set_compound_order(page, order);
274
	__SetPageHead(page);
275
	for (i = 1; i < nr_pages; i++) {
Linus Torvalds's avatar
Linus Torvalds committed
276
277
		struct page *p = page + i;

278
279
		__SetPageTail(p);
		p->first_page = page;
Linus Torvalds's avatar
Linus Torvalds committed
280
281
282
283
284
285
286
287
	}
}

static void destroy_compound_page(struct page *page, unsigned long order)
{
	int i;
	int nr_pages = 1 << order;

288
	if (unlikely(compound_order(page) != order))
289
		bad_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
290

291
	if (unlikely(!PageHead(page)))
292
			bad_page(page);
293
	__ClearPageHead(page);
294
	for (i = 1; i < nr_pages; i++) {
Linus Torvalds's avatar
Linus Torvalds committed
295
296
		struct page *p = page + i;

297
		if (unlikely(!PageTail(p) |
298
				(p->first_page != page)))
299
			bad_page(page);
300
		__ClearPageTail(p);
Linus Torvalds's avatar
Linus Torvalds committed
301
302
303
	}
}

Nick Piggin's avatar
Nick Piggin committed
304
305
306
307
static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
{
	int i;

Nick Piggin's avatar
Nick Piggin committed
308
	VM_BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM);
309
310
311
312
	/*
	 * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
	 * and __GFP_HIGHMEM from hard or soft interrupt context.
	 */
Nick Piggin's avatar
Nick Piggin committed
313
	VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
Nick Piggin's avatar
Nick Piggin committed
314
315
316
317
	for (i = 0; i < (1 << order); i++)
		clear_highpage(page + i);
}

318
319
static inline void set_page_order(struct page *page, int order)
{
320
	set_page_private(page, order);
321
	__SetPageBuddy(page);
Linus Torvalds's avatar
Linus Torvalds committed
322
323
324
325
}

static inline void rmv_page_order(struct page *page)
{
326
	__ClearPageBuddy(page);
327
	set_page_private(page, 0);
Linus Torvalds's avatar
Linus Torvalds committed
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
}

/*
 * Locate the struct page for both the matching buddy in our
 * pair (buddy1) and the combined O(n+1) page they form (page).
 *
 * 1) Any buddy B1 will have an order O twin B2 which satisfies
 * the following equation:
 *     B2 = B1 ^ (1 << O)
 * For example, if the starting buddy (buddy2) is #8 its order
 * 1 buddy is #10:
 *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
 *
 * 2) Any buddy B will have an order O+1 parent P which
 * satisfies the following equation:
 *     P = B & ~(1 << O)
 *
Andreas Mohr's avatar
Andreas Mohr committed
345
 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
Linus Torvalds's avatar
Linus Torvalds committed
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
 */
static inline struct page *
__page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
{
	unsigned long buddy_idx = page_idx ^ (1 << order);

	return page + (buddy_idx - page_idx);
}

static inline unsigned long
__find_combined_index(unsigned long page_idx, unsigned int order)
{
	return (page_idx & ~(1 << order));
}

/*
 * This function checks whether a page is free && is the buddy
 * we can do coalesce a page and its buddy if
Nick Piggin's avatar
Nick Piggin committed
364
 * (a) the buddy is not in a hole &&
365
 * (b) the buddy is in the buddy system &&
366
367
 * (c) a page and its buddy have the same order &&
 * (d) a page and its buddy are in the same zone.
368
369
370
 *
 * For recording whether a page is in the buddy system, we use PG_buddy.
 * Setting, clearing, and testing PG_buddy is serialized by zone->lock.
Linus Torvalds's avatar
Linus Torvalds committed
371
 *
372
 * For recording page's order, we use page_private(page).
Linus Torvalds's avatar
Linus Torvalds committed
373
 */
374
375
static inline int page_is_buddy(struct page *page, struct page *buddy,
								int order)
Linus Torvalds's avatar
Linus Torvalds committed
376
{
377
	if (!pfn_valid_within(page_to_pfn(buddy)))
Nick Piggin's avatar
Nick Piggin committed
378
379
		return 0;

380
381
382
383
384
	if (page_zone_id(page) != page_zone_id(buddy))
		return 0;

	if (PageBuddy(buddy) && page_order(buddy) == order) {
		BUG_ON(page_count(buddy) != 0);
385
		return 1;
386
	}
387
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
}

/*
 * Freeing function for a buddy system allocator.
 *
 * The concept of a buddy system is to maintain direct-mapped table
 * (containing bit values) for memory blocks of various "orders".
 * The bottom level table contains the map for the smallest allocatable
 * units of memory (here, pages), and each level above it describes
 * pairs of units from the levels below, hence, "buddies".
 * At a high level, all that happens here is marking the table entry
 * at the bottom level available, and propagating the changes upward
 * as necessary, plus some accounting needed to play nicely with other
 * parts of the VM system.
 * At each level, we keep a list of pages, which are heads of continuous
403
 * free pages of length of (1 << order) and marked with PG_buddy. Page's
404
 * order is recorded in page_private(page) field.
Linus Torvalds's avatar
Linus Torvalds committed
405
406
407
408
409
410
411
412
413
 * So when we are allocating or freeing one, we can derive the state of the
 * other.  That is, if we allocate a small block, and both were   
 * free, the remainder of the region must be split into blocks.   
 * If a block is freed, and its buddy is also free, then this
 * triggers coalescing into a block of larger size.            
 *
 * -- wli
 */

Nick Piggin's avatar
Nick Piggin committed
414
static inline void __free_one_page(struct page *page,
Linus Torvalds's avatar
Linus Torvalds committed
415
416
417
418
		struct zone *zone, unsigned int order)
{
	unsigned long page_idx;
	int order_size = 1 << order;
419
	int migratetype = get_pageblock_migratetype(page);
Linus Torvalds's avatar
Linus Torvalds committed
420

421
	if (unlikely(PageCompound(page)))
Linus Torvalds's avatar
Linus Torvalds committed
422
423
424
425
		destroy_compound_page(page, order);

	page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);

Nick Piggin's avatar
Nick Piggin committed
426
427
	VM_BUG_ON(page_idx & (order_size - 1));
	VM_BUG_ON(bad_range(zone, page));
Linus Torvalds's avatar
Linus Torvalds committed
428

429
	__mod_zone_page_state(zone, NR_FREE_PAGES, order_size);
Linus Torvalds's avatar
Linus Torvalds committed
430
431
432
433
434
	while (order < MAX_ORDER-1) {
		unsigned long combined_idx;
		struct page *buddy;

		buddy = __page_find_buddy(page, page_idx, order);
435
		if (!page_is_buddy(page, buddy, order))
Linus Torvalds's avatar
Linus Torvalds committed
436
			break;		/* Move the buddy up one level. */
Nick Piggin's avatar
Nick Piggin committed
437

Linus Torvalds's avatar
Linus Torvalds committed
438
		list_del(&buddy->lru);
439
		zone->free_area[order].nr_free--;
Linus Torvalds's avatar
Linus Torvalds committed
440
		rmv_page_order(buddy);
Nick Piggin's avatar
Nick Piggin committed
441
		combined_idx = __find_combined_index(page_idx, order);
Linus Torvalds's avatar
Linus Torvalds committed
442
443
444
445
446
		page = page + (combined_idx - page_idx);
		page_idx = combined_idx;
		order++;
	}
	set_page_order(page, order);
447
448
	list_add(&page->lru,
		&zone->free_area[order].free_list[migratetype]);
Linus Torvalds's avatar
Linus Torvalds committed
449
450
451
	zone->free_area[order].nr_free++;
}

452
static inline int free_pages_check(struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
453
{
Nick Piggin's avatar
Nick Piggin committed
454
455
456
	if (unlikely(page_mapcount(page) |
		(page->mapping != NULL)  |
		(page_count(page) != 0)  |
Linus Torvalds's avatar
Linus Torvalds committed
457
458
459
460
461
462
463
		(page->flags & (
			1 << PG_lru	|
			1 << PG_private |
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_slab	|
			1 << PG_swapcache |
Nick Piggin's avatar
Nick Piggin committed
464
			1 << PG_writeback |
465
466
			1 << PG_reserved |
			1 << PG_buddy ))))
467
		bad_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
468
	if (PageDirty(page))
Nick Piggin's avatar
Nick Piggin committed
469
		__ClearPageDirty(page);
470
471
472
473
474
475
	/*
	 * For now, we report if PG_reserved was found set, but do not
	 * clear it, and do not free the page.  But we shall soon need
	 * to do more, for when the ZERO_PAGE count wraps negative.
	 */
	return PageReserved(page);
Linus Torvalds's avatar
Linus Torvalds committed
476
477
478
479
480
}

/*
 * Frees a list of pages. 
 * Assumes all pages on list are in same zone, and of same order.
481
 * count is the number of pages to free.
Linus Torvalds's avatar
Linus Torvalds committed
482
483
484
485
486
487
488
 *
 * If the zone was previously in an "all pages pinned" state then look to
 * see if this freeing clears that state.
 *
 * And clear the zone's pages_scanned counter, to hold off the "all pages are
 * pinned" detection logic.
 */
Nick Piggin's avatar
Nick Piggin committed
489
490
static void free_pages_bulk(struct zone *zone, int count,
					struct list_head *list, int order)
Linus Torvalds's avatar
Linus Torvalds committed
491
{
Nick Piggin's avatar
Nick Piggin committed
492
	spin_lock(&zone->lock);
493
	zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
Linus Torvalds's avatar
Linus Torvalds committed
494
	zone->pages_scanned = 0;
Nick Piggin's avatar
Nick Piggin committed
495
496
497
	while (count--) {
		struct page *page;

Nick Piggin's avatar
Nick Piggin committed
498
		VM_BUG_ON(list_empty(list));
Linus Torvalds's avatar
Linus Torvalds committed
499
		page = list_entry(list->prev, struct page, lru);
Nick Piggin's avatar
Nick Piggin committed
500
		/* have to delete it as __free_one_page list manipulates */
Linus Torvalds's avatar
Linus Torvalds committed
501
		list_del(&page->lru);
Nick Piggin's avatar
Nick Piggin committed
502
		__free_one_page(page, zone, order);
Linus Torvalds's avatar
Linus Torvalds committed
503
	}
Nick Piggin's avatar
Nick Piggin committed
504
	spin_unlock(&zone->lock);
Linus Torvalds's avatar
Linus Torvalds committed
505
506
}

Nick Piggin's avatar
Nick Piggin committed
507
static void free_one_page(struct zone *zone, struct page *page, int order)
Linus Torvalds's avatar
Linus Torvalds committed
508
{
509
	spin_lock(&zone->lock);
510
	zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
511
	zone->pages_scanned = 0;
512
	__free_one_page(page, zone, order);
513
	spin_unlock(&zone->lock);
Nick Piggin's avatar
Nick Piggin committed
514
515
516
517
518
}

static void __free_pages_ok(struct page *page, unsigned int order)
{
	unsigned long flags;
Linus Torvalds's avatar
Linus Torvalds committed
519
	int i;
520
	int reserved = 0;
Linus Torvalds's avatar
Linus Torvalds committed
521
522

	for (i = 0 ; i < (1 << order) ; ++i)
523
		reserved += free_pages_check(page + i);
524
525
526
	if (reserved)
		return;

Nick Piggin's avatar
Nick Piggin committed
527
528
	if (!PageHighMem(page))
		debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
Nick Piggin's avatar
Nick Piggin committed
529
	arch_free_page(page, order);
Nick Piggin's avatar
Nick Piggin committed
530
	kernel_map_pages(page, 1 << order, 0);
Nick Piggin's avatar
Nick Piggin committed
531

Nick Piggin's avatar
Nick Piggin committed
532
	local_irq_save(flags);
533
	__count_vm_events(PGFREE, 1 << order);
Nick Piggin's avatar
Nick Piggin committed
534
	free_one_page(page_zone(page), page, order);
Nick Piggin's avatar
Nick Piggin committed
535
	local_irq_restore(flags);
Linus Torvalds's avatar
Linus Torvalds committed
536
537
}

538
539
540
541
542
543
544
545
/*
 * permit the bootmem allocator to evade page validation on high-order frees
 */
void fastcall __init __free_pages_bootmem(struct page *page, unsigned int order)
{
	if (order == 0) {
		__ClearPageReserved(page);
		set_page_count(page, 0);
546
		set_page_refcounted(page);
Nick Piggin's avatar
Nick Piggin committed
547
		__free_page(page);
548
549
550
	} else {
		int loop;

Nick Piggin's avatar
Nick Piggin committed
551
		prefetchw(page);
552
553
554
		for (loop = 0; loop < BITS_PER_LONG; loop++) {
			struct page *p = &page[loop];

Nick Piggin's avatar
Nick Piggin committed
555
556
			if (loop + 1 < BITS_PER_LONG)
				prefetchw(p + 1);
557
558
559
560
			__ClearPageReserved(p);
			set_page_count(p, 0);
		}

561
		set_page_refcounted(page);
Nick Piggin's avatar
Nick Piggin committed
562
		__free_pages(page, order);
563
564
565
	}
}

Linus Torvalds's avatar
Linus Torvalds committed
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580

/*
 * The order of subdivision here is critical for the IO subsystem.
 * Please do not alter this order without good reasons and regression
 * testing. Specifically, as large blocks of memory are subdivided,
 * the order in which smaller blocks are delivered depends on the order
 * they're subdivided in this function. This is the primary factor
 * influencing the order in which pages are delivered to the IO
 * subsystem according to empirical testing, and this is also justified
 * by considering the behavior of a buddy system containing a single
 * large block of memory acted on by a series of small allocations.
 * This behavior is a critical factor in sglist merging's success.
 *
 * -- wli
 */
Nick Piggin's avatar
Nick Piggin committed
581
static inline void expand(struct zone *zone, struct page *page,
582
583
	int low, int high, struct free_area *area,
	int migratetype)
Linus Torvalds's avatar
Linus Torvalds committed
584
585
586
587
588
589
590
{
	unsigned long size = 1 << high;

	while (high > low) {
		area--;
		high--;
		size >>= 1;
Nick Piggin's avatar
Nick Piggin committed
591
		VM_BUG_ON(bad_range(zone, &page[size]));
592
		list_add(&page[size].lru, &area->free_list[migratetype]);
Linus Torvalds's avatar
Linus Torvalds committed
593
594
595
596
597
598
599
600
		area->nr_free++;
		set_page_order(&page[size], high);
	}
}

/*
 * This page is about to be returned from the page allocator
 */
Nick Piggin's avatar
Nick Piggin committed
601
static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
Linus Torvalds's avatar
Linus Torvalds committed
602
{
Nick Piggin's avatar
Nick Piggin committed
603
604
605
	if (unlikely(page_mapcount(page) |
		(page->mapping != NULL)  |
		(page_count(page) != 0)  |
606
607
		(page->flags & (
			1 << PG_lru	|
Linus Torvalds's avatar
Linus Torvalds committed
608
609
610
611
			1 << PG_private	|
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_dirty	|
612
			1 << PG_slab    |
Linus Torvalds's avatar
Linus Torvalds committed
613
			1 << PG_swapcache |
Nick Piggin's avatar
Nick Piggin committed
614
			1 << PG_writeback |
615
616
			1 << PG_reserved |
			1 << PG_buddy ))))
617
		bad_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
618

619
620
621
622
623
624
625
	/*
	 * For now, we report if PG_reserved was found set, but do not
	 * clear it, and do not allocate the page: as a safety net.
	 */
	if (PageReserved(page))
		return 1;

626
	page->flags &= ~(1 << PG_uptodate | 1 << PG_error | 1 << PG_readahead |
Linus Torvalds's avatar
Linus Torvalds committed
627
			1 << PG_referenced | 1 << PG_arch_1 |
628
			1 << PG_owner_priv_1 | 1 << PG_mappedtodisk);
629
	set_page_private(page, 0);
630
	set_page_refcounted(page);
Nick Piggin's avatar
Nick Piggin committed
631
632

	arch_alloc_page(page, order);
Linus Torvalds's avatar
Linus Torvalds committed
633
	kernel_map_pages(page, 1 << order, 1);
Nick Piggin's avatar
Nick Piggin committed
634
635
636
637
638
639
640

	if (gfp_flags & __GFP_ZERO)
		prep_zero_page(page, order, gfp_flags);

	if (order && (gfp_flags & __GFP_COMP))
		prep_compound_page(page, order);

641
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
642
643
}

644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
/*
 * Go through the free lists for the given migratetype and remove
 * the smallest available page from the freelists
 */
static struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
						int migratetype)
{
	unsigned int current_order;
	struct free_area * area;
	struct page *page;

	/* Find a page of the appropriate size in the preferred list */
	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
		area = &(zone->free_area[current_order]);
		if (list_empty(&area->free_list[migratetype]))
			continue;

		page = list_entry(area->free_list[migratetype].next,
							struct page, lru);
		list_del(&page->lru);
		rmv_page_order(page);
		area->nr_free--;
		__mod_zone_page_state(zone, NR_FREE_PAGES, - (1UL << order));
		expand(zone, page, order, current_order, area, migratetype);
		return page;
	}

	return NULL;
}


675
676
677
678
679
/*
 * This array describes the order lists are fallen back to when
 * the free lists for the desirable migrate type are depleted
 */
static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = {
680
681
682
683
	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_RESERVE },
	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_RESERVE },
	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
	[MIGRATE_RESERVE]     = { MIGRATE_RESERVE,     MIGRATE_RESERVE,   MIGRATE_RESERVE }, /* Never used */
684
685
};

686
687
/*
 * Move the free pages in a range to the free lists of the requested type.
688
 * Note that start_page and end_pages are not aligned on a pageblock
689
690
691
692
693
694
695
696
 * boundary. If alignment is required, use move_freepages_block()
 */
int move_freepages(struct zone *zone,
			struct page *start_page, struct page *end_page,
			int migratetype)
{
	struct page *page;
	unsigned long order;
697
	int pages_moved = 0;
698
699
700
701
702
703
704

#ifndef CONFIG_HOLES_IN_ZONE
	/*
	 * page_zone is not safe to call in this context when
	 * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
	 * anyway as we check zone boundaries in move_freepages_block().
	 * Remove at a later date when no bug reports exist related to
Mel Gorman's avatar
Mel Gorman committed
705
	 * grouping pages by mobility
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
	 */
	BUG_ON(page_zone(start_page) != page_zone(end_page));
#endif

	for (page = start_page; page <= end_page;) {
		if (!pfn_valid_within(page_to_pfn(page))) {
			page++;
			continue;
		}

		if (!PageBuddy(page)) {
			page++;
			continue;
		}

		order = page_order(page);
		list_del(&page->lru);
		list_add(&page->lru,
			&zone->free_area[order].free_list[migratetype]);
		page += 1 << order;
726
		pages_moved += 1 << order;
727
728
	}

729
	return pages_moved;
730
731
732
733
734
735
736
737
}

int move_freepages_block(struct zone *zone, struct page *page, int migratetype)
{
	unsigned long start_pfn, end_pfn;
	struct page *start_page, *end_page;

	start_pfn = page_to_pfn(page);
738
	start_pfn = start_pfn & ~(pageblock_nr_pages-1);
739
	start_page = pfn_to_page(start_pfn);
740
741
	end_page = start_page + pageblock_nr_pages - 1;
	end_pfn = start_pfn + pageblock_nr_pages - 1;
742
743
744
745
746
747
748
749
750
751

	/* Do not cross zone boundaries */
	if (start_pfn < zone->zone_start_pfn)
		start_page = page;
	if (end_pfn >= zone->zone_start_pfn + zone->spanned_pages)
		return 0;

	return move_freepages(zone, start_page, end_page, migratetype);
}

752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
/* Return the page with the lowest PFN in the list */
static struct page *min_page(struct list_head *list)
{
	unsigned long min_pfn = -1UL;
	struct page *min_page = NULL, *page;;

	list_for_each_entry(page, list, lru) {
		unsigned long pfn = page_to_pfn(page);
		if (pfn < min_pfn) {
			min_pfn = pfn;
			min_page = page;
		}
	}

	return min_page;
}

769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
/* Remove an element from the buddy allocator from the fallback list */
static struct page *__rmqueue_fallback(struct zone *zone, int order,
						int start_migratetype)
{
	struct free_area * area;
	int current_order;
	struct page *page;
	int migratetype, i;

	/* Find the largest possible block of pages in the other list */
	for (current_order = MAX_ORDER-1; current_order >= order;
						--current_order) {
		for (i = 0; i < MIGRATE_TYPES - 1; i++) {
			migratetype = fallbacks[start_migratetype][i];

784
785
786
			/* MIGRATE_RESERVE handled later if necessary */
			if (migratetype == MIGRATE_RESERVE)
				continue;
787

788
789
790
791
			area = &(zone->free_area[current_order]);
			if (list_empty(&area->free_list[migratetype]))
				continue;

792
			/* Bias kernel allocations towards low pfns */
793
794
			page = list_entry(area->free_list[migratetype].next,
					struct page, lru);
795
796
			if (unlikely(start_migratetype != MIGRATE_MOVABLE))
				page = min_page(&area->free_list[migratetype]);
797
798
799
			area->nr_free--;

			/*
800
			 * If breaking a large block of pages, move all free
801
802
803
			 * pages to the preferred allocation list. If falling
			 * back for a reclaimable kernel allocation, be more
			 * agressive about taking ownership of free pages
804
			 */
805
			if (unlikely(current_order >= (pageblock_order >> 1)) ||
806
807
808
809
810
811
					start_migratetype == MIGRATE_RECLAIMABLE) {
				unsigned long pages;
				pages = move_freepages_block(zone, page,
								start_migratetype);

				/* Claim the whole block if over half of it is free */
812
				if (pages >= (1 << (pageblock_order-1)))
813
814
815
					set_pageblock_migratetype(page,
								start_migratetype);

816
				migratetype = start_migratetype;
817
			}
818
819
820
821
822
823
824

			/* Remove the page from the freelists */
			list_del(&page->lru);
			rmv_page_order(page);
			__mod_zone_page_state(zone, NR_FREE_PAGES,
							-(1UL << order));

825
			if (current_order == pageblock_order)
826
827
828
829
830
831
832
833
				set_pageblock_migratetype(page,
							start_migratetype);

			expand(zone, page, order, current_order, area, migratetype);
			return page;
		}
	}

834
835
	/* Use MIGRATE_RESERVE rather than fail an allocation */
	return __rmqueue_smallest(zone, order, MIGRATE_RESERVE);
836
837
}

838
/*
Linus Torvalds's avatar
Linus Torvalds committed
839
840
841
 * Do the hard work of removing an element from the buddy allocator.
 * Call me with the zone->lock already held.
 */
842
843
static struct page *__rmqueue(struct zone *zone, unsigned int order,
						int migratetype)
Linus Torvalds's avatar
Linus Torvalds committed
844
845
846
{
	struct page *page;

847
	page = __rmqueue_smallest(zone, order, migratetype);
848

849
850
	if (unlikely(!page))
		page = __rmqueue_fallback(zone, order, migratetype);
851
852

	return page;
Linus Torvalds's avatar
Linus Torvalds committed
853
854
855
856
857
858
859
860
}

/* 
 * Obtain a specified number of elements from the buddy allocator, all under
 * a single hold of the lock, for efficiency.  Add them to the supplied list.
 * Returns the number of new pages which were placed at *list.
 */
static int rmqueue_bulk(struct zone *zone, unsigned int order, 
861
862
			unsigned long count, struct list_head *list,
			int migratetype)
Linus Torvalds's avatar
Linus Torvalds committed
863
864
865
{
	int i;
	
Nick Piggin's avatar
Nick Piggin committed
866
	spin_lock(&zone->lock);
Linus Torvalds's avatar
Linus Torvalds committed
867
	for (i = 0; i < count; ++i) {
868
		struct page *page = __rmqueue(zone, order, migratetype);
Nick Piggin's avatar
Nick Piggin committed
869
		if (unlikely(page == NULL))
Linus Torvalds's avatar
Linus Torvalds committed
870
			break;
871
872
		list_add(&page->lru, list);
		set_page_private(page, migratetype);
Linus Torvalds's avatar
Linus Torvalds committed
873
	}
Nick Piggin's avatar
Nick Piggin committed
874
	spin_unlock(&zone->lock);
Nick Piggin's avatar
Nick Piggin committed
875
	return i;
Linus Torvalds's avatar
Linus Torvalds committed
876
877
}

878
#ifdef CONFIG_NUMA
879
/*
880
881
882
883
 * Called from the vmstat counter updater to drain pagesets of this
 * currently executing processor on remote nodes after they have
 * expired.
 *
884
885
 * Note that this function must be called with the thread pinned to
 * a single processor.
886
 */
887
void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
888
889
{
	unsigned long flags;
890
	int to_drain;
891

892
893
894
895
896
897
898
899
	local_irq_save(flags);
	if (pcp->count >= pcp->batch)
		to_drain = pcp->batch;
	else
		to_drain = pcp->count;
	free_pages_bulk(zone, to_drain, &pcp->list, 0);
	pcp->count -= to_drain;
	local_irq_restore(flags);
900
901
902
}
#endif

Linus Torvalds's avatar
Linus Torvalds committed
903
904
static void __drain_pages(unsigned int cpu)
{
Nick Piggin's avatar
Nick Piggin committed
905
	unsigned long flags;
Linus Torvalds's avatar
Linus Torvalds committed
906
907
908
909
910
911
	struct zone *zone;
	int i;

	for_each_zone(zone) {
		struct per_cpu_pageset *pset;

912
913
914
		if (!populated_zone(zone))
			continue;

915
		pset = zone_pcp(zone, cpu);
Linus Torvalds's avatar
Linus Torvalds committed
916
917
918
919
		for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
			struct per_cpu_pages *pcp;

			pcp = &pset->pcp[i];
Nick Piggin's avatar
Nick Piggin committed
920
			local_irq_save(flags);
Nick Piggin's avatar
Nick Piggin committed
921
922
			free_pages_bulk(zone, pcp->count, &pcp->list, 0);
			pcp->count = 0;
Nick Piggin's avatar
Nick Piggin committed
923
			local_irq_restore(flags);
Linus Torvalds's avatar
Linus Torvalds committed
924
925
926
927
		}
	}
}

928
#ifdef CONFIG_HIBERNATION
Linus Torvalds's avatar
Linus Torvalds committed
929
930
931

void mark_free_pages(struct zone *zone)
{
932
933
	unsigned long pfn, max_zone_pfn;
	unsigned long flags;
934
	int order, t;
Linus Torvalds's avatar
Linus Torvalds committed
935
936
937
938
939
940
	struct list_head *curr;

	if (!zone->spanned_pages)
		return;

	spin_lock_irqsave(&zone->lock, flags);
941
942
943
944
945
946

	max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
		if (pfn_valid(pfn)) {
			struct page *page = pfn_to_page(pfn);

947
948
			if (!swsusp_page_is_forbidden(page))
				swsusp_unset_page_free(page);
949
		}
Linus Torvalds's avatar
Linus Torvalds committed
950

951
952
	for_each_migratetype_order(order, t) {
		list_for_each(curr, &zone->free_area[order].free_list[t]) {
953
			unsigned long i;
Linus Torvalds's avatar
Linus Torvalds committed
954

955
956
			pfn = page_to_pfn(list_entry(curr, struct page, lru));
			for (i = 0; i < (1UL << order); i++)
957
				swsusp_set_page_free(pfn_to_page(pfn + i));
958
		}
959
	}
Linus Torvalds's avatar
Linus Torvalds committed
960
961
	spin_unlock_irqrestore(&zone->lock, flags);
}
962
#endif /* CONFIG_PM */
Linus Torvalds's avatar
Linus Torvalds committed
963
964
965
966
967
968
969
970
971
972
973
974

/*
 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
 */
void drain_local_pages(void)
{
	unsigned long flags;

	local_irq_save(flags);	
	__drain_pages(smp_processor_id());
	local_irq_restore(flags);	
}
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993

void smp_drain_local_pages(void *arg)
{
	drain_local_pages();
}

/*
 * Spill all the per-cpu pages from all CPUs back into the buddy allocator
 */
void drain_all_local_pages(void)
{
	unsigned long flags;

	local_irq_save(flags);
	__drain_pages(smp_processor_id());
	local_irq_restore(flags);

	smp_call_function(smp_drain_local_pages, NULL, 0, 1);
}
Linus Torvalds's avatar
Linus Torvalds committed
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005

/*
 * Free a 0-order page
 */
static void fastcall free_hot_cold_page(struct page *page, int cold)
{
	struct zone *zone = page_zone(page);
	struct per_cpu_pages *pcp;
	unsigned long flags;

	if (PageAnon(page))
		page->mapping = NULL;
1006
	if (free_pages_check(page))
1007
1008
		return;

Nick Piggin's avatar
Nick Piggin committed
1009
1010
	if (!PageHighMem(page))
		debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
Nick Piggin's avatar
Nick Piggin committed
1011
	arch_free_page(page, 0);
1012
1013
	kernel_map_pages(page, 1, 0);

1014
	pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
Linus Torvalds's avatar
Linus Torvalds committed
1015
	local_irq_save(flags);
1016
	__count_vm_event(PGFREE);
Linus Torvalds's avatar
Linus Torvalds committed
1017
	list_add(&page->lru, &pcp->list);
1018
	set_page_private(page, get_pageblock_migratetype(page));
Linus Torvalds's avatar
Linus Torvalds committed
1019
	pcp->count++;
Nick Piggin's avatar
Nick Piggin committed
1020
1021
1022
1023
	if (pcp->count >= pcp->high) {
		free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
		pcp->count -= pcp->batch;
	}
Linus Torvalds's avatar
Linus Torvalds committed
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
	local_irq_restore(flags);
	put_cpu();
}

void fastcall free_hot_page(struct page *page)
{
	free_hot_cold_page(page, 0);
}
	
void fastcall free_cold_page(struct page *page)
{
	free_hot_cold_page(page, 1);
}

1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
/*
 * split_page takes a non-compound higher-order page, and splits it into
 * n (1<<order) sub-pages: page[0..n]
 * Each sub-page must be freed individually.
 *
 * Note: this is probably too low level an operation for use in drivers.
 * Please consult with lkml before using this in your driver.
 */
void split_page(struct page *page, unsigned int order)
{
	int i;

Nick Piggin's avatar
Nick Piggin committed
1050
1051
	VM_BUG_ON(PageCompound(page));
	VM_BUG_ON(!page_count(page));
1052
1053
	for (i = 1; i < (1 << order); i++)
		set_page_refcounted(page + i);
1054
1055
}

Linus Torvalds's avatar
Linus Torvalds committed
1056
1057
1058
1059
1060
/*
 * Really, prep_compound_page() should be called from __rmqueue_bulk().  But
 * we cheat by calling it from here, in the order > 0 path.  Saves a branch
 * or two.
 */
Nick Piggin's avatar
Nick Piggin committed
1061
1062
static struct page *buffered_rmqueue(struct zonelist *zonelist,
			struct zone *zone, int order, gfp_t gfp_flags)
Linus Torvalds's avatar
Linus Torvalds committed
1063
1064
{
	unsigned long flags;
1065
	struct page *page;
Linus Torvalds's avatar
Linus Torvalds committed
1066
	int cold = !!(gfp_flags & __GFP_COLD);
Nick Piggin's avatar
Nick Piggin committed
1067
	int cpu;
1068
	int migratetype = allocflags_to_migratetype(gfp_flags);
Linus Torvalds's avatar
Linus Torvalds committed
1069

1070
again:
Nick Piggin's avatar
Nick Piggin committed
1071
	cpu  = get_cpu();
Nick Piggin's avatar
Nick Piggin committed
1072
	if (likely(order == 0)) {
Linus Torvalds's avatar
Linus Torvalds committed
1073
1074
		struct per_cpu_pages *pcp;

Nick Piggin's avatar
Nick Piggin committed
1075
		pcp = &zone_pcp(zone, cpu)->pcp[cold];
Linus Torvalds's avatar
Linus Torvalds committed
1076
		local_irq_save(flags);
Nick Piggin's avatar
Nick Piggin committed
1077
		if (!pcp->count) {
1078
			pcp->count = rmqueue_bulk(zone, 0,
1079
					pcp->batch, &pcp->list, migratetype);
Nick Piggin's avatar
Nick Piggin committed
1080
1081
			if (unlikely(!pcp->count))
				goto failed;
Linus Torvalds's avatar
Linus Torvalds committed
1082
		}
1083

1084
		/* Find a page of the appropriate migrate type */
1085
1086
		list_for_each_entry(page, &pcp->list, lru)
			if (page_private(page) == migratetype)
1087
1088
				break;

1089
1090
		/* Allocate more to the pcp list if necessary */
		if (unlikely(&page->lru == &pcp->list)) {
1091
1092
1093
1094
			pcp->count += rmqueue_bulk(zone, 0,
					pcp->batch, &pcp->list, migratetype);
			page = list_entry(pcp->list.next, struct page, lru);
		}
1095
1096
1097

		list_del(&page->lru);
		pcp->count--;
Rohit Seth's avatar
Rohit Seth committed
1098
	} else {
Linus Torvalds's avatar
Linus Torvalds committed
1099
		spin_lock_irqsave(&zone->lock, flags);
1100
		page = __rmqueue(zone, order, migratetype);
Nick Piggin's avatar
Nick Piggin committed
1101
1102
1103
</