page_alloc.c 98 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 30 31 32 33 34
#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/pagevec.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/topology.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
35
#include <linux/memory_hotplug.h>
Linus Torvalds's avatar
Linus Torvalds committed
36 37
#include <linux/nodemask.h>
#include <linux/vmalloc.h>
38
#include <linux/mempolicy.h>
39
#include <linux/stop_machine.h>
40 41
#include <linux/sort.h>
#include <linux/pfn.h>
42
#include <linux/backing-dev.h>
43
#include <linux/fault-inject.h>
Linus Torvalds's avatar
Linus Torvalds committed
44 45

#include <asm/tlbflush.h>
46
#include <asm/div64.h>
Linus Torvalds's avatar
Linus Torvalds committed
47 48 49 50 51 52
#include "internal.h"

/*
 * MCD - HACK: Find somewhere to initialize this EARLY, or make this
 * initializer cleaner
 */
53
nodemask_t node_online_map __read_mostly = { { [0] = 1UL } };
54
EXPORT_SYMBOL(node_online_map);
55
nodemask_t node_possible_map __read_mostly = NODE_MASK_ALL;
56
EXPORT_SYMBOL(node_possible_map);
57
unsigned long totalram_pages __read_mostly;
58
unsigned long totalreserve_pages __read_mostly;
Linus Torvalds's avatar
Linus Torvalds committed
59
long nr_swap_pages;
60
int percpu_pagelist_fraction;
Linus Torvalds's avatar
Linus Torvalds committed
61

62
static void __free_pages_ok(struct page *page, unsigned int order);
63

Linus Torvalds's avatar
Linus Torvalds committed
64 65 66 67 68 69 70
/*
 * 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
71 72 73
 *
 * 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
74
 */
75
int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
76
#ifdef CONFIG_ZONE_DMA
77
	 256,
78
#endif
79
#ifdef CONFIG_ZONE_DMA32
80
	 256,
81
#endif
82
#ifdef CONFIG_HIGHMEM
83
	 32
84
#endif
85
};
Linus Torvalds's avatar
Linus Torvalds committed
86 87 88

EXPORT_SYMBOL(totalram_pages);

89
static char * const zone_names[MAX_NR_ZONES] = {
90
#ifdef CONFIG_ZONE_DMA
91
	 "DMA",
92
#endif
93
#ifdef CONFIG_ZONE_DMA32
94
	 "DMA32",
95
#endif
96
	 "Normal",
97
#ifdef CONFIG_HIGHMEM
98
	 "HighMem"
99
#endif
100 101
};

Linus Torvalds's avatar
Linus Torvalds committed
102 103
int min_free_kbytes = 1024;

104 105
unsigned long __meminitdata nr_kernel_pages;
unsigned long __meminitdata nr_all_pages;
106
static unsigned long __meminitdata dma_reserve;
Linus Torvalds's avatar
Linus Torvalds committed
107

108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128
#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

129 130 131 132
  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];
133
#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
134 135
  static unsigned long __meminitdata node_boundary_start_pfn[MAX_NUMNODES];
  static unsigned long __meminitdata node_boundary_end_pfn[MAX_NUMNODES];
136
#endif /* CONFIG_MEMORY_HOTPLUG_RESERVE */
137 138
#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */

Miklos Szeredi's avatar
Miklos Szeredi committed
139 140 141 142 143
#if MAX_NUMNODES > 1
int nr_node_ids __read_mostly = MAX_NUMNODES;
EXPORT_SYMBOL(nr_node_ids);
#endif

Nick Piggin's avatar
Nick Piggin committed
144
#ifdef CONFIG_DEBUG_VM
145
static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
146
{
147 148 149
	int ret = 0;
	unsigned seq;
	unsigned long pfn = page_to_pfn(page);
150

151 152 153 154 155 156 157 158 159
	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;
160 161 162 163
}

static int page_is_consistent(struct zone *zone, struct page *page)
{
164
	if (!pfn_valid_within(page_to_pfn(page)))
165
		return 0;
Linus Torvalds's avatar
Linus Torvalds committed
166
	if (zone != page_zone(page))
167 168 169 170 171 172 173 174 175 176
		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
177
		return 1;
178 179 180
	if (!page_is_consistent(zone, page))
		return 1;

Linus Torvalds's avatar
Linus Torvalds committed
181 182
	return 0;
}
Nick Piggin's avatar
Nick Piggin committed
183 184 185 186 187 188 189
#else
static inline int bad_range(struct zone *zone, struct page *page)
{
	return 0;
}
#endif

190
static void bad_page(struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
191
{
192
	printk(KERN_EMERG "Bad page state in process '%s'\n"
193 194 195
		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",
196 197 198
		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
199
	dump_stack();
200 201
	page->flags &= ~(1 << PG_lru	|
			1 << PG_private |
Linus Torvalds's avatar
Linus Torvalds committed
202 203 204
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_dirty	|
205 206
			1 << PG_reclaim |
			1 << PG_slab    |
Linus Torvalds's avatar
Linus Torvalds committed
207
			1 << PG_swapcache |
208 209
			1 << PG_writeback |
			1 << PG_buddy );
Linus Torvalds's avatar
Linus Torvalds committed
210 211 212
	set_page_count(page, 0);
	reset_page_mapcount(page);
	page->mapping = NULL;
213
	add_taint(TAINT_BAD_PAGE);
Linus Torvalds's avatar
Linus Torvalds committed
214 215 216 217 218 219 220 221 222 223 224 225
}

/*
 * 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).
 *
226 227 228
 * 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
229
 */
230 231 232

static void free_compound_page(struct page *page)
{
233
	__free_pages_ok(page, compound_order(page));
234 235
}

Linus Torvalds's avatar
Linus Torvalds committed
236 237 238 239 240
static void prep_compound_page(struct page *page, unsigned long order)
{
	int i;
	int nr_pages = 1 << order;

241
	set_compound_page_dtor(page, free_compound_page);
242
	set_compound_order(page, order);
243
	__SetPageHead(page);
244
	for (i = 1; i < nr_pages; i++) {
Linus Torvalds's avatar
Linus Torvalds committed
245 246
		struct page *p = page + i;

247 248
		__SetPageTail(p);
		p->first_page = page;
Linus Torvalds's avatar
Linus Torvalds committed
249 250 251 252 253 254 255 256
	}
}

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

257
	if (unlikely(compound_order(page) != order))
258
		bad_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
259

260
	if (unlikely(!PageHead(page)))
261
			bad_page(page);
262
	__ClearPageHead(page);
263
	for (i = 1; i < nr_pages; i++) {
Linus Torvalds's avatar
Linus Torvalds committed
264 265
		struct page *p = page + i;

266
		if (unlikely(!PageTail(p) |
267
				(p->first_page != page)))
268
			bad_page(page);
269
		__ClearPageTail(p);
Linus Torvalds's avatar
Linus Torvalds committed
270 271 272
	}
}

Nick Piggin's avatar
Nick Piggin committed
273 274 275 276
static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
{
	int i;

Nick Piggin's avatar
Nick Piggin committed
277
	VM_BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM);
278 279 280 281
	/*
	 * 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
282
	VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
Nick Piggin's avatar
Nick Piggin committed
283 284 285 286
	for (i = 0; i < (1 << order); i++)
		clear_highpage(page + i);
}

Linus Torvalds's avatar
Linus Torvalds committed
287 288 289 290 291
/*
 * function for dealing with page's order in buddy system.
 * zone->lock is already acquired when we use these.
 * So, we don't need atomic page->flags operations here.
 */
292 293
static inline unsigned long page_order(struct page *page)
{
294
	return page_private(page);
Linus Torvalds's avatar
Linus Torvalds committed
295 296
}

297 298
static inline void set_page_order(struct page *page, int order)
{
299
	set_page_private(page, order);
300
	__SetPageBuddy(page);
Linus Torvalds's avatar
Linus Torvalds committed
301 302 303 304
}

static inline void rmv_page_order(struct page *page)
{
305
	__ClearPageBuddy(page);
306
	set_page_private(page, 0);
Linus Torvalds's avatar
Linus Torvalds committed
307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323
}

/*
 * 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
324
 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
Linus Torvalds's avatar
Linus Torvalds committed
325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342
 */
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
343
 * (a) the buddy is not in a hole &&
344
 * (b) the buddy is in the buddy system &&
345 346
 * (c) a page and its buddy have the same order &&
 * (d) a page and its buddy are in the same zone.
347 348 349
 *
 * 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
350
 *
351
 * For recording page's order, we use page_private(page).
Linus Torvalds's avatar
Linus Torvalds committed
352
 */
353 354
static inline int page_is_buddy(struct page *page, struct page *buddy,
								int order)
Linus Torvalds's avatar
Linus Torvalds committed
355
{
356
	if (!pfn_valid_within(page_to_pfn(buddy)))
Nick Piggin's avatar
Nick Piggin committed
357 358
		return 0;

359 360 361 362 363
	if (page_zone_id(page) != page_zone_id(buddy))
		return 0;

	if (PageBuddy(buddy) && page_order(buddy) == order) {
		BUG_ON(page_count(buddy) != 0);
364
		return 1;
365
	}
366
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
367 368 369 370 371 372 373 374 375 376 377 378 379 380 381
}

/*
 * 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
382
 * free pages of length of (1 << order) and marked with PG_buddy. Page's
383
 * order is recorded in page_private(page) field.
Linus Torvalds's avatar
Linus Torvalds committed
384 385 386 387 388 389 390 391 392
 * 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
393
static inline void __free_one_page(struct page *page,
Linus Torvalds's avatar
Linus Torvalds committed
394 395 396 397 398
		struct zone *zone, unsigned int order)
{
	unsigned long page_idx;
	int order_size = 1 << order;

399
	if (unlikely(PageCompound(page)))
Linus Torvalds's avatar
Linus Torvalds committed
400 401 402 403
		destroy_compound_page(page, order);

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

Nick Piggin's avatar
Nick Piggin committed
404 405
	VM_BUG_ON(page_idx & (order_size - 1));
	VM_BUG_ON(bad_range(zone, page));
Linus Torvalds's avatar
Linus Torvalds committed
406

407
	__mod_zone_page_state(zone, NR_FREE_PAGES, order_size);
Linus Torvalds's avatar
Linus Torvalds committed
408 409 410 411 412 413
	while (order < MAX_ORDER-1) {
		unsigned long combined_idx;
		struct free_area *area;
		struct page *buddy;

		buddy = __page_find_buddy(page, page_idx, order);
414
		if (!page_is_buddy(page, buddy, order))
Linus Torvalds's avatar
Linus Torvalds committed
415
			break;		/* Move the buddy up one level. */
Nick Piggin's avatar
Nick Piggin committed
416

Linus Torvalds's avatar
Linus Torvalds committed
417 418 419 420
		list_del(&buddy->lru);
		area = zone->free_area + order;
		area->nr_free--;
		rmv_page_order(buddy);
Nick Piggin's avatar
Nick Piggin committed
421
		combined_idx = __find_combined_index(page_idx, order);
Linus Torvalds's avatar
Linus Torvalds committed
422 423 424 425 426 427 428 429 430
		page = page + (combined_idx - page_idx);
		page_idx = combined_idx;
		order++;
	}
	set_page_order(page, order);
	list_add(&page->lru, &zone->free_area[order].free_list);
	zone->free_area[order].nr_free++;
}

431
static inline int free_pages_check(struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
432
{
Nick Piggin's avatar
Nick Piggin committed
433 434 435
	if (unlikely(page_mapcount(page) |
		(page->mapping != NULL)  |
		(page_count(page) != 0)  |
Linus Torvalds's avatar
Linus Torvalds committed
436 437 438 439 440 441 442
		(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
443
			1 << PG_writeback |
444 445
			1 << PG_reserved |
			1 << PG_buddy ))))
446
		bad_page(page);
447 448 449 450 451 452
	/*
	 * PageReclaim == PageTail. It is only an error
	 * for PageReclaim to be set if PageCompound is clear.
	 */
	if (unlikely(!PageCompound(page) && PageReclaim(page)))
		bad_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
453
	if (PageDirty(page))
Nick Piggin's avatar
Nick Piggin committed
454
		__ClearPageDirty(page);
455 456 457 458 459 460
	/*
	 * 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
461 462 463 464 465
}

/*
 * Frees a list of pages. 
 * Assumes all pages on list are in same zone, and of same order.
466
 * count is the number of pages to free.
Linus Torvalds's avatar
Linus Torvalds committed
467 468 469 470 471 472 473
 *
 * 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
474 475
static void free_pages_bulk(struct zone *zone, int count,
					struct list_head *list, int order)
Linus Torvalds's avatar
Linus Torvalds committed
476
{
Nick Piggin's avatar
Nick Piggin committed
477
	spin_lock(&zone->lock);
Linus Torvalds's avatar
Linus Torvalds committed
478 479
	zone->all_unreclaimable = 0;
	zone->pages_scanned = 0;
Nick Piggin's avatar
Nick Piggin committed
480 481 482
	while (count--) {
		struct page *page;

Nick Piggin's avatar
Nick Piggin committed
483
		VM_BUG_ON(list_empty(list));
Linus Torvalds's avatar
Linus Torvalds committed
484
		page = list_entry(list->prev, struct page, lru);
Nick Piggin's avatar
Nick Piggin committed
485
		/* have to delete it as __free_one_page list manipulates */
Linus Torvalds's avatar
Linus Torvalds committed
486
		list_del(&page->lru);
Nick Piggin's avatar
Nick Piggin committed
487
		__free_one_page(page, zone, order);
Linus Torvalds's avatar
Linus Torvalds committed
488
	}
Nick Piggin's avatar
Nick Piggin committed
489
	spin_unlock(&zone->lock);
Linus Torvalds's avatar
Linus Torvalds committed
490 491
}

Nick Piggin's avatar
Nick Piggin committed
492
static void free_one_page(struct zone *zone, struct page *page, int order)
Linus Torvalds's avatar
Linus Torvalds committed
493
{
494 495 496
	spin_lock(&zone->lock);
	zone->all_unreclaimable = 0;
	zone->pages_scanned = 0;
497
	__free_one_page(page, zone, order);
498
	spin_unlock(&zone->lock);
Nick Piggin's avatar
Nick Piggin committed
499 500 501 502 503
}

static void __free_pages_ok(struct page *page, unsigned int order)
{
	unsigned long flags;
Linus Torvalds's avatar
Linus Torvalds committed
504
	int i;
505
	int reserved = 0;
Linus Torvalds's avatar
Linus Torvalds committed
506 507

	for (i = 0 ; i < (1 << order) ; ++i)
508
		reserved += free_pages_check(page + i);
509 510 511
	if (reserved)
		return;

Nick Piggin's avatar
Nick Piggin committed
512 513
	if (!PageHighMem(page))
		debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
Nick Piggin's avatar
Nick Piggin committed
514
	arch_free_page(page, order);
Nick Piggin's avatar
Nick Piggin committed
515
	kernel_map_pages(page, 1 << order, 0);
Nick Piggin's avatar
Nick Piggin committed
516

Nick Piggin's avatar
Nick Piggin committed
517
	local_irq_save(flags);
518
	__count_vm_events(PGFREE, 1 << order);
Nick Piggin's avatar
Nick Piggin committed
519
	free_one_page(page_zone(page), page, order);
Nick Piggin's avatar
Nick Piggin committed
520
	local_irq_restore(flags);
Linus Torvalds's avatar
Linus Torvalds committed
521 522
}

523 524 525 526 527 528 529 530
/*
 * 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);
531
		set_page_refcounted(page);
Nick Piggin's avatar
Nick Piggin committed
532
		__free_page(page);
533 534 535
	} else {
		int loop;

Nick Piggin's avatar
Nick Piggin committed
536
		prefetchw(page);
537 538 539
		for (loop = 0; loop < BITS_PER_LONG; loop++) {
			struct page *p = &page[loop];

Nick Piggin's avatar
Nick Piggin committed
540 541
			if (loop + 1 < BITS_PER_LONG)
				prefetchw(p + 1);
542 543 544 545
			__ClearPageReserved(p);
			set_page_count(p, 0);
		}

546
		set_page_refcounted(page);
Nick Piggin's avatar
Nick Piggin committed
547
		__free_pages(page, order);
548 549 550
	}
}

Linus Torvalds's avatar
Linus Torvalds committed
551 552 553 554 555 556 557 558 559 560 561 562 563 564 565

/*
 * 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
566
static inline void expand(struct zone *zone, struct page *page,
Linus Torvalds's avatar
Linus Torvalds committed
567 568 569 570 571 572 573 574
 	int low, int high, struct free_area *area)
{
	unsigned long size = 1 << high;

	while (high > low) {
		area--;
		high--;
		size >>= 1;
Nick Piggin's avatar
Nick Piggin committed
575
		VM_BUG_ON(bad_range(zone, &page[size]));
Linus Torvalds's avatar
Linus Torvalds committed
576 577 578 579 580 581 582 583 584
		list_add(&page[size].lru, &area->free_list);
		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
585
static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
Linus Torvalds's avatar
Linus Torvalds committed
586
{
Nick Piggin's avatar
Nick Piggin committed
587 588 589
	if (unlikely(page_mapcount(page) |
		(page->mapping != NULL)  |
		(page_count(page) != 0)  |
590 591
		(page->flags & (
			1 << PG_lru	|
Linus Torvalds's avatar
Linus Torvalds committed
592 593 594 595 596
			1 << PG_private	|
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_dirty	|
			1 << PG_reclaim	|
597
			1 << PG_slab    |
Linus Torvalds's avatar
Linus Torvalds committed
598
			1 << PG_swapcache |
Nick Piggin's avatar
Nick Piggin committed
599
			1 << PG_writeback |
600 601
			1 << PG_reserved |
			1 << PG_buddy ))))
602
		bad_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
603

604 605 606 607 608 609 610
	/*
	 * 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;

Linus Torvalds's avatar
Linus Torvalds committed
611 612
	page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
			1 << PG_referenced | 1 << PG_arch_1 |
613
			1 << PG_owner_priv_1 | 1 << PG_mappedtodisk);
614
	set_page_private(page, 0);
615
	set_page_refcounted(page);
Nick Piggin's avatar
Nick Piggin committed
616 617

	arch_alloc_page(page, order);
Linus Torvalds's avatar
Linus Torvalds committed
618
	kernel_map_pages(page, 1 << order, 1);
Nick Piggin's avatar
Nick Piggin committed
619 620 621 622 623 624 625

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

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

626
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647
}

/* 
 * Do the hard work of removing an element from the buddy allocator.
 * Call me with the zone->lock already held.
 */
static struct page *__rmqueue(struct zone *zone, unsigned int order)
{
	struct free_area * area;
	unsigned int current_order;
	struct page *page;

	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
		area = zone->free_area + current_order;
		if (list_empty(&area->free_list))
			continue;

		page = list_entry(area->free_list.next, struct page, lru);
		list_del(&page->lru);
		rmv_page_order(page);
		area->nr_free--;
648
		__mod_zone_page_state(zone, NR_FREE_PAGES, - (1UL << order));
Nick Piggin's avatar
Nick Piggin committed
649 650
		expand(zone, page, order, current_order, area);
		return page;
Linus Torvalds's avatar
Linus Torvalds committed
651 652 653 654 655 656 657 658 659 660 661 662 663 664 665
	}

	return NULL;
}

/* 
 * 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, 
			unsigned long count, struct list_head *list)
{
	int i;
	
Nick Piggin's avatar
Nick Piggin committed
666
	spin_lock(&zone->lock);
Linus Torvalds's avatar
Linus Torvalds committed
667
	for (i = 0; i < count; ++i) {
Nick Piggin's avatar
Nick Piggin committed
668 669
		struct page *page = __rmqueue(zone, order);
		if (unlikely(page == NULL))
Linus Torvalds's avatar
Linus Torvalds committed
670 671 672
			break;
		list_add_tail(&page->lru, list);
	}
Nick Piggin's avatar
Nick Piggin committed
673
	spin_unlock(&zone->lock);
Nick Piggin's avatar
Nick Piggin committed
674
	return i;
Linus Torvalds's avatar
Linus Torvalds committed
675 676
}

677
#ifdef CONFIG_NUMA
678
/*
679 680 681 682
 * Called from the vmstat counter updater to drain pagesets of this
 * currently executing processor on remote nodes after they have
 * expired.
 *
683 684
 * Note that this function must be called with the thread pinned to
 * a single processor.
685
 */
686
void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
687 688
{
	unsigned long flags;
689
	int to_drain;
690

691 692 693 694 695 696 697 698
	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);
699 700 701
}
#endif

Linus Torvalds's avatar
Linus Torvalds committed
702 703
static void __drain_pages(unsigned int cpu)
{
Nick Piggin's avatar
Nick Piggin committed
704
	unsigned long flags;
Linus Torvalds's avatar
Linus Torvalds committed
705 706 707 708 709 710
	struct zone *zone;
	int i;

	for_each_zone(zone) {
		struct per_cpu_pageset *pset;

711 712 713
		if (!populated_zone(zone))
			continue;

714
		pset = zone_pcp(zone, cpu);
Linus Torvalds's avatar
Linus Torvalds committed
715 716 717 718
		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
719
			local_irq_save(flags);
Nick Piggin's avatar
Nick Piggin committed
720 721
			free_pages_bulk(zone, pcp->count, &pcp->list, 0);
			pcp->count = 0;
Nick Piggin's avatar
Nick Piggin committed
722
			local_irq_restore(flags);
Linus Torvalds's avatar
Linus Torvalds committed
723 724 725 726 727 728 729 730
		}
	}
}

#ifdef CONFIG_PM

void mark_free_pages(struct zone *zone)
{
731 732
	unsigned long pfn, max_zone_pfn;
	unsigned long flags;
Linus Torvalds's avatar
Linus Torvalds committed
733 734 735 736 737 738 739
	int order;
	struct list_head *curr;

	if (!zone->spanned_pages)
		return;

	spin_lock_irqsave(&zone->lock, flags);
740 741 742 743 744 745

	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);

746 747
			if (!swsusp_page_is_forbidden(page))
				swsusp_unset_page_free(page);
748
		}
Linus Torvalds's avatar
Linus Torvalds committed
749 750 751

	for (order = MAX_ORDER - 1; order >= 0; --order)
		list_for_each(curr, &zone->free_area[order].free_list) {
752
			unsigned long i;
Linus Torvalds's avatar
Linus Torvalds committed
753

754 755
			pfn = page_to_pfn(list_entry(curr, struct page, lru));
			for (i = 0; i < (1UL << order); i++)
756
				swsusp_set_page_free(pfn_to_page(pfn + i));
757
		}
Linus Torvalds's avatar
Linus Torvalds committed
758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785

	spin_unlock_irqrestore(&zone->lock, flags);
}

/*
 * 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);	
}
#endif /* CONFIG_PM */

/*
 * 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;
786
	if (free_pages_check(page))
787 788
		return;

Nick Piggin's avatar
Nick Piggin committed
789 790
	if (!PageHighMem(page))
		debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
Nick Piggin's avatar
Nick Piggin committed
791
	arch_free_page(page, 0);
792 793
	kernel_map_pages(page, 1, 0);

794
	pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
Linus Torvalds's avatar
Linus Torvalds committed
795
	local_irq_save(flags);
796
	__count_vm_event(PGFREE);
Linus Torvalds's avatar
Linus Torvalds committed
797 798
	list_add(&page->lru, &pcp->list);
	pcp->count++;
Nick Piggin's avatar
Nick Piggin committed
799 800 801 802
	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
803 804 805 806 807 808 809 810 811 812 813 814 815 816
	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);
}

817 818 819 820 821 822 823 824 825 826 827 828
/*
 * 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
829 830
	VM_BUG_ON(PageCompound(page));
	VM_BUG_ON(!page_count(page));
831 832
	for (i = 1; i < (1 << order); i++)
		set_page_refcounted(page + i);
833 834
}

Linus Torvalds's avatar
Linus Torvalds committed
835 836 837 838 839
/*
 * 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
840 841
static struct page *buffered_rmqueue(struct zonelist *zonelist,
			struct zone *zone, int order, gfp_t gfp_flags)
Linus Torvalds's avatar
Linus Torvalds committed
842 843
{
	unsigned long flags;
844
	struct page *page;
Linus Torvalds's avatar
Linus Torvalds committed
845
	int cold = !!(gfp_flags & __GFP_COLD);
Nick Piggin's avatar
Nick Piggin committed
846
	int cpu;
Linus Torvalds's avatar
Linus Torvalds committed
847

848
again:
Nick Piggin's avatar
Nick Piggin committed
849
	cpu  = get_cpu();
Nick Piggin's avatar
Nick Piggin committed
850
	if (likely(order == 0)) {
Linus Torvalds's avatar
Linus Torvalds committed
851 852
		struct per_cpu_pages *pcp;

Nick Piggin's avatar
Nick Piggin committed
853
		pcp = &zone_pcp(zone, cpu)->pcp[cold];
Linus Torvalds's avatar
Linus Torvalds committed
854
		local_irq_save(flags);
Nick Piggin's avatar
Nick Piggin committed
855
		if (!pcp->count) {
856
			pcp->count = rmqueue_bulk(zone, 0,
Linus Torvalds's avatar
Linus Torvalds committed
857
						pcp->batch, &pcp->list);
Nick Piggin's avatar
Nick Piggin committed
858 859
			if (unlikely(!pcp->count))
				goto failed;
Linus Torvalds's avatar
Linus Torvalds committed
860
		}
Nick Piggin's avatar
Nick Piggin committed
861 862 863
		page = list_entry(pcp->list.next, struct page, lru);
		list_del(&page->lru);
		pcp->count--;
Rohit Seth's avatar
Rohit Seth committed
864
	} else {
Linus Torvalds's avatar
Linus Torvalds committed
865 866
		spin_lock_irqsave(&zone->lock, flags);
		page = __rmqueue(zone, order);
Nick Piggin's avatar
Nick Piggin committed
867 868 869
		spin_unlock(&zone->lock);
		if (!page)
			goto failed;
Linus Torvalds's avatar
Linus Torvalds committed
870 871
	}

872
	__count_zone_vm_events(PGALLOC, zone, 1 << order);
873
	zone_statistics(zonelist, zone);
Nick Piggin's avatar
Nick Piggin committed
874 875
	local_irq_restore(flags);
	put_cpu();
Linus Torvalds's avatar
Linus Torvalds committed
876

Nick Piggin's avatar
Nick Piggin committed
877
	VM_BUG_ON(bad_range(zone, page));
Nick Piggin's avatar
Nick Piggin committed
878
	if (prep_new_page(page, order, gfp_flags))
Nick Piggin's avatar
Nick Piggin committed
879
		goto again;
Linus Torvalds's avatar
Linus Torvalds committed
880
	return page;
Nick Piggin's avatar
Nick Piggin committed
881 882 883 884 885

failed:
	local_irq_restore(flags);
	put_cpu();
	return NULL;
Linus Torvalds's avatar
Linus Torvalds committed
886 887
}

Rohit Seth's avatar
Rohit Seth committed
888
#define ALLOC_NO_WATERMARKS	0x01 /* don't check watermarks at all */
889 890 891 892 893 894
#define ALLOC_WMARK_MIN		0x02 /* use pages_min watermark */
#define ALLOC_WMARK_LOW		0x04 /* use pages_low watermark */
#define ALLOC_WMARK_HIGH	0x08 /* use pages_high watermark */
#define ALLOC_HARDER		0x10 /* try to alloc harder */
#define ALLOC_HIGH		0x20 /* __GFP_HIGH set */
#define ALLOC_CPUSET		0x40 /* check for correct cpuset */
Rohit Seth's avatar
Rohit Seth committed
895

896 897 898 899 900 901 902
#ifdef CONFIG_FAIL_PAGE_ALLOC

static struct fail_page_alloc_attr {
	struct fault_attr attr;

	u32 ignore_gfp_highmem;
	u32 ignore_gfp_wait;
903
	u32 min_order;
904 905 906 907 908

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS

	struct dentry *ignore_gfp_highmem_file;
	struct dentry *ignore_gfp_wait_file;
909
	struct dentry *min_order_file;
910 911 912 913 914

#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

} fail_page_alloc = {
	.attr = FAULT_ATTR_INITIALIZER,
915 916
	.ignore_gfp_wait = 1,
	.ignore_gfp_highmem = 1,
917
	.min_order = 1,
918 919 920 921 922 923 924 925 926 927
};

static int __init setup_fail_page_alloc(char *str)
{
	return setup_fault_attr(&fail_page_alloc.attr, str);
}
__setup("fail_page_alloc=", setup_fail_page_alloc);

static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
928 929
	if (order < fail_page_alloc.min_order)
		return 0;
930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960
	if (gfp_mask & __GFP_NOFAIL)
		return 0;
	if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
		return 0;
	if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
		return 0;

	return should_fail(&fail_page_alloc.attr, 1 << order);
}

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS

static int __init fail_page_alloc_debugfs(void)
{
	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
	struct dentry *dir;
	int err;

	err = init_fault_attr_dentries(&fail_page_alloc.attr,
				       "fail_page_alloc");
	if (err)
		return err;
	dir = fail_page_alloc.attr.dentries.dir;

	fail_page_alloc.ignore_gfp_wait_file =
		debugfs_create_bool("ignore-gfp-wait", mode, dir,
				      &fail_page_alloc.ignore_gfp_wait);

	fail_page_alloc.ignore_gfp_highmem_file =
		debugfs_create_bool("ignore-gfp-highmem", mode, dir,
				      &fail_page_alloc.ignore_gfp_highmem);
961 962 963
	fail_page_alloc.min_order_file =
		debugfs_create_u32("min-order", mode, dir,
				   &fail_page_alloc.min_order);
964 965

	if (!fail_page_alloc.ignore_gfp_wait_file ||
966 967
            !fail_page_alloc.ignore_gfp_highmem_file ||
            !fail_page_alloc.min_order_file) {
968 969 970
		err = -ENOMEM;
		debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
		debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
971
		debugfs_remove(fail_page_alloc.min_order_file);
972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990
		cleanup_fault_attr_dentries(&fail_page_alloc.attr);
	}

	return err;
}

late_initcall(fail_page_alloc_debugfs);

#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

#else /* CONFIG_FAIL_PAGE_ALLOC */

static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
	return 0;
}

#endif /* CONFIG_FAIL_PAGE_ALLOC */

Linus Torvalds's avatar
Linus Torvalds committed
991 992 993 994 995
/*
 * Return 1 if free pages are above 'mark'. This takes into account the order
 * of the allocation.
 */
int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
Rohit Seth's avatar
Rohit Seth committed
996
		      int classzone_idx, int alloc_flags)
Linus Torvalds's avatar
Linus Torvalds committed
997 998
{
	/* free_pages my go negative - that's OK */
999 1000
	long min = mark;
	long free_pages = zone_page_state(z, NR_FREE_PAGES) - (1 << order) + 1;
Linus Torvalds's avatar
Linus Torvalds committed
1001 1002
	int o;

Rohit Seth's avatar
Rohit Seth committed
1003
	if (alloc_flags & ALLOC_HIGH)
Linus Torvalds's avatar
Linus Torvalds committed
1004
		min -= min / 2;
Rohit Seth's avatar
Rohit Seth committed
1005
	if (alloc_flags & ALLOC_HARDER)
Linus Torvalds's avatar
Linus Torvalds committed
1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022
		min -= min / 4;

	if (free_pages <= min + z->lowmem_reserve[classzone_idx])
		return 0;
	for (o = 0; o < order; o++) {
		/* At the next order, this order's pages become unavailable */
		free_pages -= z->free_area[o].nr_free << o;

		/* Require fewer higher order pages to be free */
		min >>= 1;

		if (free_pages <= min)
			return 0;
	}
	return 1;
}

1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083