page_alloc.c 66.8 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 24
/*
 *  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/config.h>
#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>
25
#include <linux/kernel.h>
Linus Torvalds's avatar
Linus Torvalds committed
26 27 28 29 30 31 32 33 34 35
#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>
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>
Linus Torvalds's avatar
Linus Torvalds committed
40 41 42 43 44 45 46 47

#include <asm/tlbflush.h>
#include "internal.h"

/*
 * MCD - HACK: Find somewhere to initialize this EARLY, or make this
 * initializer cleaner
 */
48
nodemask_t node_online_map __read_mostly = { { [0] = 1UL } };
49
EXPORT_SYMBOL(node_online_map);
50
nodemask_t node_possible_map __read_mostly = NODE_MASK_ALL;
51
EXPORT_SYMBOL(node_possible_map);
52
struct pglist_data *pgdat_list __read_mostly;
53 54
unsigned long totalram_pages __read_mostly;
unsigned long totalhigh_pages __read_mostly;
Linus Torvalds's avatar
Linus Torvalds committed
55
long nr_swap_pages;
56
int percpu_pagelist_fraction;
Linus Torvalds's avatar
Linus Torvalds committed
57

58 59
static void fastcall free_hot_cold_page(struct page *page, int cold);

Linus Torvalds's avatar
Linus Torvalds committed
60 61 62 63 64 65 66
/*
 * 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
67 68 69
 *
 * 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
70
 */
71
int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { 256, 256, 32 };
Linus Torvalds's avatar
Linus Torvalds committed
72 73 74 75 76 77 78

EXPORT_SYMBOL(totalram_pages);

/*
 * Used by page_zone() to look up the address of the struct zone whose
 * id is encoded in the upper bits of page->flags
 */
79
struct zone *zone_table[1 << ZONETABLE_SHIFT] __read_mostly;
Linus Torvalds's avatar
Linus Torvalds committed
80 81
EXPORT_SYMBOL(zone_table);

82
static char *zone_names[MAX_NR_ZONES] = { "DMA", "DMA32", "Normal", "HighMem" };
Linus Torvalds's avatar
Linus Torvalds committed
83 84 85 86 87
int min_free_kbytes = 1024;

unsigned long __initdata nr_kernel_pages;
unsigned long __initdata nr_all_pages;

Nick Piggin's avatar
Nick Piggin committed
88
#ifdef CONFIG_DEBUG_VM
89
static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
90
{
91 92 93
	int ret = 0;
	unsigned seq;
	unsigned long pfn = page_to_pfn(page);
94

95 96 97 98 99 100 101 102 103
	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;
104 105 106 107
}

static int page_is_consistent(struct zone *zone, struct page *page)
{
Linus Torvalds's avatar
Linus Torvalds committed
108 109
#ifdef CONFIG_HOLES_IN_ZONE
	if (!pfn_valid(page_to_pfn(page)))
110
		return 0;
Linus Torvalds's avatar
Linus Torvalds committed
111 112
#endif
	if (zone != page_zone(page))
113 114 115 116 117 118 119 120 121 122
		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
123
		return 1;
124 125 126
	if (!page_is_consistent(zone, page))
		return 1;

Linus Torvalds's avatar
Linus Torvalds committed
127 128 129
	return 0;
}

Nick Piggin's avatar
Nick Piggin committed
130 131 132 133 134 135 136
#else
static inline int bad_range(struct zone *zone, struct page *page)
{
	return 0;
}
#endif

137
static void bad_page(struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
138
{
139
	printk(KERN_EMERG "Bad page state in process '%s'\n"
140 141 142
		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",
143 144 145
		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
146
	dump_stack();
147 148
	page->flags &= ~(1 << PG_lru	|
			1 << PG_private |
Linus Torvalds's avatar
Linus Torvalds committed
149 150 151
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_dirty	|
152 153
			1 << PG_reclaim |
			1 << PG_slab    |
Linus Torvalds's avatar
Linus Torvalds committed
154
			1 << PG_swapcache |
155
			1 << PG_writeback );
Linus Torvalds's avatar
Linus Torvalds committed
156 157 158
	set_page_count(page, 0);
	reset_page_mapcount(page);
	page->mapping = NULL;
159
	add_taint(TAINT_BAD_PAGE);
Linus Torvalds's avatar
Linus Torvalds committed
160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189
}

/*
 * 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).
 *
 * The first tail page's ->mapping, if non-zero, holds the address of the
 * compound page's put_page() function.
 *
 * The order of the allocation is stored in the first tail page's ->index
 * This is only for debug at present.  This usage means that zero-order pages
 * may not be compound.
 */
static void prep_compound_page(struct page *page, unsigned long order)
{
	int i;
	int nr_pages = 1 << order;

	page[1].mapping = NULL;
	page[1].index = order;
	for (i = 0; i < nr_pages; i++) {
		struct page *p = page + i;

		SetPageCompound(p);
190
		set_page_private(p, (unsigned long)page);
Linus Torvalds's avatar
Linus Torvalds committed
191 192 193 194 195 196 197 198
	}
}

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

199 200
	if (unlikely(page[1].index != order))
		bad_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
201 202 203 204

	for (i = 0; i < nr_pages; i++) {
		struct page *p = page + i;

205 206 207
		if (unlikely(!PageCompound(p) |
				(page_private(p) != (unsigned long)page)))
			bad_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
208 209 210 211 212 213 214 215 216 217
		ClearPageCompound(p);
	}
}

/*
 * 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.
 */
static inline unsigned long page_order(struct page *page) {
218
	return page_private(page);
Linus Torvalds's avatar
Linus Torvalds committed
219 220 221
}

static inline void set_page_order(struct page *page, int order) {
222
	set_page_private(page, order);
Linus Torvalds's avatar
Linus Torvalds committed
223 224 225 226 227 228
	__SetPagePrivate(page);
}

static inline void rmv_page_order(struct page *page)
{
	__ClearPagePrivate(page);
229
	set_page_private(page, 0);
Linus Torvalds's avatar
Linus Torvalds committed
230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265
}

/*
 * 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)
 *
 * Assumption: *_mem_map is contigious at least up to MAX_ORDER
 */
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
266 267 268 269
 * (a) the buddy is not in a hole &&
 * (b) the buddy is free &&
 * (c) the buddy is on the buddy system &&
 * (d) a page and its buddy have the same order.
270
 * for recording page's order, we use page_private(page) and PG_private.
Linus Torvalds's avatar
Linus Torvalds committed
271 272 273 274
 *
 */
static inline int page_is_buddy(struct page *page, int order)
{
Nick Piggin's avatar
Nick Piggin committed
275 276 277 278 279
#ifdef CONFIG_HOLES_IN_ZONE
	if (!pfn_valid(page_to_pfn(page)))
		return 0;
#endif

Linus Torvalds's avatar
Linus Torvalds committed
280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300
       if (PagePrivate(page)           &&
           (page_order(page) == order) &&
            page_count(page) == 0)
               return 1;
       return 0;
}

/*
 * 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
 * free pages of length of (1 << order) and marked with PG_Private.Page's
301
 * order is recorded in page_private(page) field.
Linus Torvalds's avatar
Linus Torvalds committed
302 303 304 305 306 307 308 309 310
 * 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
311
static inline void __free_one_page(struct page *page,
Linus Torvalds's avatar
Linus Torvalds committed
312 313 314 315 316
		struct zone *zone, unsigned int order)
{
	unsigned long page_idx;
	int order_size = 1 << order;

317
	if (unlikely(PageCompound(page)))
Linus Torvalds's avatar
Linus Torvalds committed
318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333
		destroy_compound_page(page, order);

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

	BUG_ON(page_idx & (order_size - 1));
	BUG_ON(bad_range(zone, page));

	zone->free_pages += order_size;
	while (order < MAX_ORDER-1) {
		unsigned long combined_idx;
		struct free_area *area;
		struct page *buddy;

		buddy = __page_find_buddy(page, page_idx, order);
		if (!page_is_buddy(buddy, order))
			break;		/* Move the buddy up one level. */
Nick Piggin's avatar
Nick Piggin committed
334

Linus Torvalds's avatar
Linus Torvalds committed
335 336 337 338
		list_del(&buddy->lru);
		area = zone->free_area + order;
		area->nr_free--;
		rmv_page_order(buddy);
Nick Piggin's avatar
Nick Piggin committed
339
		combined_idx = __find_combined_index(page_idx, order);
Linus Torvalds's avatar
Linus Torvalds committed
340 341 342 343 344 345 346 347 348
		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++;
}

349
static inline int free_pages_check(struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
350
{
Nick Piggin's avatar
Nick Piggin committed
351 352 353
	if (unlikely(page_mapcount(page) |
		(page->mapping != NULL)  |
		(page_count(page) != 0)  |
Linus Torvalds's avatar
Linus Torvalds committed
354 355 356 357 358 359 360 361
		(page->flags & (
			1 << PG_lru	|
			1 << PG_private |
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_reclaim	|
			1 << PG_slab	|
			1 << PG_swapcache |
Nick Piggin's avatar
Nick Piggin committed
362
			1 << PG_writeback |
Nick Piggin's avatar
Nick Piggin committed
363
			1 << PG_reserved ))))
364
		bad_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
365
	if (PageDirty(page))
Nick Piggin's avatar
Nick Piggin committed
366
		__ClearPageDirty(page);
367 368 369 370 371 372
	/*
	 * 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
373 374 375 376 377
}

/*
 * Frees a list of pages. 
 * Assumes all pages on list are in same zone, and of same order.
378
 * count is the number of pages to free.
Linus Torvalds's avatar
Linus Torvalds committed
379 380 381 382 383 384 385
 *
 * 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
386 387
static void free_pages_bulk(struct zone *zone, int count,
					struct list_head *list, int order)
Linus Torvalds's avatar
Linus Torvalds committed
388
{
Nick Piggin's avatar
Nick Piggin committed
389
	spin_lock(&zone->lock);
Linus Torvalds's avatar
Linus Torvalds committed
390 391
	zone->all_unreclaimable = 0;
	zone->pages_scanned = 0;
Nick Piggin's avatar
Nick Piggin committed
392 393 394 395
	while (count--) {
		struct page *page;

		BUG_ON(list_empty(list));
Linus Torvalds's avatar
Linus Torvalds committed
396
		page = list_entry(list->prev, struct page, lru);
Nick Piggin's avatar
Nick Piggin committed
397
		/* have to delete it as __free_one_page list manipulates */
Linus Torvalds's avatar
Linus Torvalds committed
398
		list_del(&page->lru);
Nick Piggin's avatar
Nick Piggin committed
399
		__free_one_page(page, zone, order);
Linus Torvalds's avatar
Linus Torvalds committed
400
	}
Nick Piggin's avatar
Nick Piggin committed
401
	spin_unlock(&zone->lock);
Linus Torvalds's avatar
Linus Torvalds committed
402 403
}

Nick Piggin's avatar
Nick Piggin committed
404
static void free_one_page(struct zone *zone, struct page *page, int order)
Linus Torvalds's avatar
Linus Torvalds committed
405 406
{
	LIST_HEAD(list);
Nick Piggin's avatar
Nick Piggin committed
407 408 409 410 411 412 413
	list_add(&page->lru, &list);
	free_pages_bulk(zone, 1, &list, order);
}

static void __free_pages_ok(struct page *page, unsigned int order)
{
	unsigned long flags;
Linus Torvalds's avatar
Linus Torvalds committed
414
	int i;
415
	int reserved = 0;
Linus Torvalds's avatar
Linus Torvalds committed
416 417

	arch_free_page(page, order);
418 419
	if (!PageHighMem(page))
		mutex_debug_check_no_locks_freed(page_address(page),
420
						 PAGE_SIZE<<order);
Linus Torvalds's avatar
Linus Torvalds committed
421 422

#ifndef CONFIG_MMU
Nick Piggin's avatar
Nick Piggin committed
423 424
	for (i = 1 ; i < (1 << order) ; ++i)
		__put_page(page + i);
Linus Torvalds's avatar
Linus Torvalds committed
425 426 427
#endif

	for (i = 0 ; i < (1 << order) ; ++i)
428
		reserved += free_pages_check(page + i);
429 430 431
	if (reserved)
		return;

Nick Piggin's avatar
Nick Piggin committed
432
	kernel_map_pages(page, 1 << order, 0);
Nick Piggin's avatar
Nick Piggin committed
433
	local_irq_save(flags);
Nick Piggin's avatar
Nick Piggin committed
434
	__mod_page_state(pgfree, 1 << order);
Nick Piggin's avatar
Nick Piggin committed
435
	free_one_page(page_zone(page), page, order);
Nick Piggin's avatar
Nick Piggin committed
436
	local_irq_restore(flags);
Linus Torvalds's avatar
Linus Torvalds committed
437 438
}

439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471
/*
 * 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);

		free_hot_cold_page(page, 0);
	} else {
		LIST_HEAD(list);
		int loop;

		for (loop = 0; loop < BITS_PER_LONG; loop++) {
			struct page *p = &page[loop];

			if (loop + 16 < BITS_PER_LONG)
				prefetchw(p + 16);
			__ClearPageReserved(p);
			set_page_count(p, 0);
		}

		arch_free_page(page, order);

		mod_page_state(pgfree, 1 << order);

		list_add(&page->lru, &list);
		kernel_map_pages(page, 1 << order, 0);
		free_pages_bulk(page_zone(page), 1, &list, order);
	}
}

Linus Torvalds's avatar
Linus Torvalds committed
472 473 474 475 476 477 478 479 480 481 482 483 484 485 486

/*
 * 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
487
static inline void expand(struct zone *zone, struct page *page,
Linus Torvalds's avatar
Linus Torvalds committed
488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505
 	int low, int high, struct free_area *area)
{
	unsigned long size = 1 << high;

	while (high > low) {
		area--;
		high--;
		size >>= 1;
		BUG_ON(bad_range(zone, &page[size]));
		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
 */
506
static int prep_new_page(struct page *page, int order)
Linus Torvalds's avatar
Linus Torvalds committed
507
{
Nick Piggin's avatar
Nick Piggin committed
508 509 510
	if (unlikely(page_mapcount(page) |
		(page->mapping != NULL)  |
		(page_count(page) != 0)  |
511 512
		(page->flags & (
			1 << PG_lru	|
Linus Torvalds's avatar
Linus Torvalds committed
513 514 515 516 517
			1 << PG_private	|
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_dirty	|
			1 << PG_reclaim	|
518
			1 << PG_slab    |
Linus Torvalds's avatar
Linus Torvalds committed
519
			1 << PG_swapcache |
Nick Piggin's avatar
Nick Piggin committed
520
			1 << PG_writeback |
Nick Piggin's avatar
Nick Piggin committed
521
			1 << PG_reserved ))))
522
		bad_page(page);
Linus Torvalds's avatar
Linus Torvalds committed
523

524 525 526 527 528 529 530
	/*
	 * 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
531 532 533
	page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
			1 << PG_referenced | 1 << PG_arch_1 |
			1 << PG_checked | 1 << PG_mappedtodisk);
534
	set_page_private(page, 0);
Linus Torvalds's avatar
Linus Torvalds committed
535 536
	set_page_refs(page, order);
	kernel_map_pages(page, 1 << order, 1);
537
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559
}

/* 
 * 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--;
		zone->free_pages -= 1UL << order;
Nick Piggin's avatar
Nick Piggin committed
560 561
		expand(zone, page, order, current_order, area);
		return page;
Linus Torvalds's avatar
Linus Torvalds committed
562 563 564 565 566 567 568 569 570 571 572 573 574 575 576
	}

	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
577
	spin_lock(&zone->lock);
Linus Torvalds's avatar
Linus Torvalds committed
578
	for (i = 0; i < count; ++i) {
Nick Piggin's avatar
Nick Piggin committed
579 580
		struct page *page = __rmqueue(zone, order);
		if (unlikely(page == NULL))
Linus Torvalds's avatar
Linus Torvalds committed
581 582 583
			break;
		list_add_tail(&page->lru, list);
	}
Nick Piggin's avatar
Nick Piggin committed
584
	spin_unlock(&zone->lock);
Nick Piggin's avatar
Nick Piggin committed
585
	return i;
Linus Torvalds's avatar
Linus Torvalds committed
586 587
}

588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603
#ifdef CONFIG_NUMA
/* Called from the slab reaper to drain remote pagesets */
void drain_remote_pages(void)
{
	struct zone *zone;
	int i;
	unsigned long flags;

	local_irq_save(flags);
	for_each_zone(zone) {
		struct per_cpu_pageset *pset;

		/* Do not drain local pagesets */
		if (zone->zone_pgdat->node_id == numa_node_id())
			continue;

Nick Piggin's avatar
Nick Piggin committed
604
		pset = zone_pcp(zone, smp_processor_id());
605 606 607 608
		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
609 610
			free_pages_bulk(zone, pcp->count, &pcp->list, 0);
			pcp->count = 0;
611 612 613 614 615 616
		}
	}
	local_irq_restore(flags);
}
#endif

Linus Torvalds's avatar
Linus Torvalds committed
617 618 619
#if defined(CONFIG_PM) || defined(CONFIG_HOTPLUG_CPU)
static void __drain_pages(unsigned int cpu)
{
Nick Piggin's avatar
Nick Piggin committed
620
	unsigned long flags;
Linus Torvalds's avatar
Linus Torvalds committed
621 622 623 624 625 626
	struct zone *zone;
	int i;

	for_each_zone(zone) {
		struct per_cpu_pageset *pset;

627
		pset = zone_pcp(zone, cpu);
Linus Torvalds's avatar
Linus Torvalds committed
628 629 630 631
		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
632
			local_irq_save(flags);
Nick Piggin's avatar
Nick Piggin committed
633 634
			free_pages_bulk(zone, pcp->count, &pcp->list, 0);
			pcp->count = 0;
Nick Piggin's avatar
Nick Piggin committed
635
			local_irq_restore(flags);
Linus Torvalds's avatar
Linus Torvalds committed
636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680
		}
	}
}
#endif /* CONFIG_PM || CONFIG_HOTPLUG_CPU */

#ifdef CONFIG_PM

void mark_free_pages(struct zone *zone)
{
	unsigned long zone_pfn, flags;
	int order;
	struct list_head *curr;

	if (!zone->spanned_pages)
		return;

	spin_lock_irqsave(&zone->lock, flags);
	for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
		ClearPageNosaveFree(pfn_to_page(zone_pfn + zone->zone_start_pfn));

	for (order = MAX_ORDER - 1; order >= 0; --order)
		list_for_each(curr, &zone->free_area[order].free_list) {
			unsigned long start_pfn, i;

			start_pfn = page_to_pfn(list_entry(curr, struct page, lru));

			for (i=0; i < (1<<order); i++)
				SetPageNosaveFree(pfn_to_page(start_pfn+i));
	}
	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 */

Nick Piggin's avatar
Nick Piggin committed
681
static void zone_statistics(struct zonelist *zonelist, struct zone *z, int cpu)
Linus Torvalds's avatar
Linus Torvalds committed
682 683 684 685 686 687
{
#ifdef CONFIG_NUMA
	pg_data_t *pg = z->zone_pgdat;
	pg_data_t *orig = zonelist->zones[0]->zone_pgdat;
	struct per_cpu_pageset *p;

Nick Piggin's avatar
Nick Piggin committed
688
	p = zone_pcp(z, cpu);
Linus Torvalds's avatar
Linus Torvalds committed
689
	if (pg == orig) {
690
		p->numa_hit++;
Linus Torvalds's avatar
Linus Torvalds committed
691 692
	} else {
		p->numa_miss++;
693
		zone_pcp(zonelist->zones[0], cpu)->numa_foreign++;
Linus Torvalds's avatar
Linus Torvalds committed
694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714
	}
	if (pg == NODE_DATA(numa_node_id()))
		p->local_node++;
	else
		p->other_node++;
#endif
}

/*
 * 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;

	arch_free_page(page, 0);

	if (PageAnon(page))
		page->mapping = NULL;
715
	if (free_pages_check(page))
716 717 718 719
		return;

	kernel_map_pages(page, 1, 0);

720
	pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
Linus Torvalds's avatar
Linus Torvalds committed
721
	local_irq_save(flags);
Nick Piggin's avatar
Nick Piggin committed
722
	__inc_page_state(pgfree);
Linus Torvalds's avatar
Linus Torvalds committed
723 724
	list_add(&page->lru, &pcp->list);
	pcp->count++;
Nick Piggin's avatar
Nick Piggin committed
725 726 727 728
	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
729 730 731 732 733 734 735 736 737 738 739 740 741 742
	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);
}

743
static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
Linus Torvalds's avatar
Linus Torvalds committed
744 745 746 747 748 749 750 751 752 753 754 755 756
{
	int i;

	BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM);
	for(i = 0; i < (1 << order); i++)
		clear_highpage(page + i);
}

/*
 * 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
757 758
static struct page *buffered_rmqueue(struct zonelist *zonelist,
			struct zone *zone, int order, gfp_t gfp_flags)
Linus Torvalds's avatar
Linus Torvalds committed
759 760
{
	unsigned long flags;
761
	struct page *page;
Linus Torvalds's avatar
Linus Torvalds committed
762
	int cold = !!(gfp_flags & __GFP_COLD);
Nick Piggin's avatar
Nick Piggin committed
763
	int cpu;
Linus Torvalds's avatar
Linus Torvalds committed
764

765
again:
Nick Piggin's avatar
Nick Piggin committed
766
	cpu  = get_cpu();
Nick Piggin's avatar
Nick Piggin committed
767
	if (likely(order == 0)) {
Linus Torvalds's avatar
Linus Torvalds committed
768 769
		struct per_cpu_pages *pcp;

Nick Piggin's avatar
Nick Piggin committed
770
		pcp = &zone_pcp(zone, cpu)->pcp[cold];
Linus Torvalds's avatar
Linus Torvalds committed
771
		local_irq_save(flags);
Nick Piggin's avatar
Nick Piggin committed
772
		if (!pcp->count) {
Linus Torvalds's avatar
Linus Torvalds committed
773 774
			pcp->count += rmqueue_bulk(zone, 0,
						pcp->batch, &pcp->list);
Nick Piggin's avatar
Nick Piggin committed
775 776
			if (unlikely(!pcp->count))
				goto failed;
Linus Torvalds's avatar
Linus Torvalds committed
777
		}
Nick Piggin's avatar
Nick Piggin committed
778 779 780
		page = list_entry(pcp->list.next, struct page, lru);
		list_del(&page->lru);
		pcp->count--;
Rohit Seth's avatar
Rohit Seth committed
781
	} else {
Linus Torvalds's avatar
Linus Torvalds committed
782 783
		spin_lock_irqsave(&zone->lock, flags);
		page = __rmqueue(zone, order);
Nick Piggin's avatar
Nick Piggin committed
784 785 786
		spin_unlock(&zone->lock);
		if (!page)
			goto failed;
Linus Torvalds's avatar
Linus Torvalds committed
787 788
	}

Nick Piggin's avatar
Nick Piggin committed
789 790 791 792
	__mod_page_state_zone(zone, pgalloc, 1 << order);
	zone_statistics(zonelist, zone, cpu);
	local_irq_restore(flags);
	put_cpu();
Linus Torvalds's avatar
Linus Torvalds committed
793

Nick Piggin's avatar
Nick Piggin committed
794 795 796
	BUG_ON(bad_range(zone, page));
	if (prep_new_page(page, order))
		goto again;
Linus Torvalds's avatar
Linus Torvalds committed
797

Nick Piggin's avatar
Nick Piggin committed
798 799 800 801 802
	if (gfp_flags & __GFP_ZERO)
		prep_zero_page(page, order, gfp_flags);

	if (order && (gfp_flags & __GFP_COMP))
		prep_compound_page(page, order);
Linus Torvalds's avatar
Linus Torvalds committed
803
	return page;
Nick Piggin's avatar
Nick Piggin committed
804 805 806 807 808

failed:
	local_irq_restore(flags);
	put_cpu();
	return NULL;
Linus Torvalds's avatar
Linus Torvalds committed
809 810
}

Rohit Seth's avatar
Rohit Seth committed
811
#define ALLOC_NO_WATERMARKS	0x01 /* don't check watermarks at all */
812 813 814 815 816 817
#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
818

Linus Torvalds's avatar
Linus Torvalds committed
819 820 821 822 823
/*
 * 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
824
		      int classzone_idx, int alloc_flags)
Linus Torvalds's avatar
Linus Torvalds committed
825 826 827 828 829
{
	/* free_pages my go negative - that's OK */
	long min = mark, free_pages = z->free_pages - (1 << order) + 1;
	int o;

Rohit Seth's avatar
Rohit Seth committed
830
	if (alloc_flags & ALLOC_HIGH)
Linus Torvalds's avatar
Linus Torvalds committed
831
		min -= min / 2;
Rohit Seth's avatar
Rohit Seth committed
832
	if (alloc_flags & ALLOC_HARDER)
Linus Torvalds's avatar
Linus Torvalds committed
833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849
		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;
}

Rohit Seth's avatar
Rohit Seth committed
850 851 852 853 854 855 856
/*
 * get_page_from_freeliest goes through the zonelist trying to allocate
 * a page.
 */
static struct page *
get_page_from_freelist(gfp_t gfp_mask, unsigned int order,
		struct zonelist *zonelist, int alloc_flags)
Martin Hicks's avatar
Martin Hicks committed
857
{
Rohit Seth's avatar
Rohit Seth committed
858 859 860 861 862 863 864 865 866 867 868 869 870 871
	struct zone **z = zonelist->zones;
	struct page *page = NULL;
	int classzone_idx = zone_idx(*z);

	/*
	 * Go through the zonelist once, looking for a zone with enough free.
	 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
	 */
	do {
		if ((alloc_flags & ALLOC_CPUSET) &&
				!cpuset_zone_allowed(*z, gfp_mask))
			continue;

		if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
872 873 874 875 876 877 878 879
			unsigned long mark;
			if (alloc_flags & ALLOC_WMARK_MIN)
				mark = (*z)->pages_min;
			else if (alloc_flags & ALLOC_WMARK_LOW)
				mark = (*z)->pages_low;
			else
				mark = (*z)->pages_high;
			if (!zone_watermark_ok(*z, order, mark,
Rohit Seth's avatar
Rohit Seth committed
880
				    classzone_idx, alloc_flags))
881 882 883
				if (!zone_reclaim_mode ||
				    !zone_reclaim(*z, gfp_mask, order))
					continue;
Rohit Seth's avatar
Rohit Seth committed
884 885
		}

Nick Piggin's avatar
Nick Piggin committed
886
		page = buffered_rmqueue(zonelist, *z, order, gfp_mask);
Rohit Seth's avatar
Rohit Seth committed
887 888 889 890 891
		if (page) {
			break;
		}
	} while (*(++z) != NULL);
	return page;
Martin Hicks's avatar
Martin Hicks committed
892 893
}

Linus Torvalds's avatar
Linus Torvalds committed
894 895 896 897
/*
 * This is the 'heart' of the zoned buddy allocator.
 */
struct page * fastcall
898
__alloc_pages(gfp_t gfp_mask, unsigned int order,
Linus Torvalds's avatar
Linus Torvalds committed
899 900
		struct zonelist *zonelist)
{
Al Viro's avatar
Al Viro committed
901
	const gfp_t wait = gfp_mask & __GFP_WAIT;
Rohit Seth's avatar
Rohit Seth committed
902
	struct zone **z;
Linus Torvalds's avatar
Linus Torvalds committed
903 904 905 906
	struct page *page;
	struct reclaim_state reclaim_state;
	struct task_struct *p = current;
	int do_retry;
Rohit Seth's avatar
Rohit Seth committed
907
	int alloc_flags;
Linus Torvalds's avatar
Linus Torvalds committed
908 909 910 911
	int did_some_progress;

	might_sleep_if(wait);

912
restart:
Rohit Seth's avatar
Rohit Seth committed
913
	z = zonelist->zones;  /* the list of zones suitable for gfp_mask */
Linus Torvalds's avatar
Linus Torvalds committed
914

Rohit Seth's avatar
Rohit Seth committed
915
	if (unlikely(*z == NULL)) {
Linus Torvalds's avatar
Linus Torvalds committed
916 917 918
		/* Should this ever happen?? */
		return NULL;
	}
919

Rohit Seth's avatar
Rohit Seth committed
920
	page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
921
				zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET);
Rohit Seth's avatar
Rohit Seth committed
922 923
	if (page)
		goto got_pg;
Linus Torvalds's avatar
Linus Torvalds committed
924

925
	do {
Rohit Seth's avatar
Rohit Seth committed
926
		wakeup_kswapd(*z, order);
927
	} while (*(++z));
Linus Torvalds's avatar
Linus Torvalds committed
928

929
	/*
Rohit Seth's avatar
Rohit Seth committed
930 931 932 933 934 935
	 * OK, we're below the kswapd watermark and have kicked background
	 * reclaim. Now things get more complex, so set up alloc_flags according
	 * to how we want to proceed.
	 *
	 * The caller may dip into page reserves a bit more if the caller
	 * cannot run direct reclaim, or if the caller has realtime scheduling
Paul Jackson's avatar
Paul Jackson committed
936 937
	 * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
	 * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
938
	 */
939
	alloc_flags = ALLOC_WMARK_MIN;
Rohit Seth's avatar
Rohit Seth committed
940 941 942 943
	if ((unlikely(rt_task(p)) && !in_interrupt()) || !wait)
		alloc_flags |= ALLOC_HARDER;
	if (gfp_mask & __GFP_HIGH)
		alloc_flags |= ALLOC_HIGH;
944
	alloc_flags |= ALLOC_CPUSET;
Linus Torvalds's avatar
Linus Torvalds committed
945 946 947

	/*
	 * Go through the zonelist again. Let __GFP_HIGH and allocations
Rohit Seth's avatar
Rohit Seth committed
948
	 * coming from realtime tasks go deeper into reserves.
Linus Torvalds's avatar
Linus Torvalds committed
949 950 951
	 *
	 * This is the last chance, in general, before the goto nopage.
	 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
952
	 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
Linus Torvalds's avatar
Linus Torvalds committed
953
	 */
Rohit Seth's avatar
Rohit Seth committed
954 955 956
	page = get_page_from_freelist(gfp_mask, order, zonelist, alloc_flags);
	if (page)
		goto got_pg;
Linus Torvalds's avatar
Linus Torvalds committed
957 958

	/* This allocation should allow future memory freeing. */
959 960 961 962

	if (((p->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE)))
			&& !in_interrupt()) {
		if (!(gfp_mask & __GFP_NOMEMALLOC)) {
Kirill Korotaev's avatar
Kirill Korotaev committed
963
nofail_alloc:
964
			/* go through the zonelist yet again, ignoring mins */
Rohit Seth's avatar
Rohit Seth committed
965
			page = get_page_from_freelist(gfp_mask, order,
966
				zonelist, ALLOC_NO_WATERMARKS);
Rohit Seth's avatar
Rohit Seth committed
967 968
			if (page)
				goto got_pg;
Kirill Korotaev's avatar
Kirill Korotaev committed
969 970 971 972
			if (gfp_mask & __GFP_NOFAIL) {
				blk_congestion_wait(WRITE, HZ/50);
				goto nofail_alloc;
			}
Linus Torvalds's avatar
Linus Torvalds committed
973 974 975 976 977 978 979 980 981 982 983 984
		}
		goto nopage;
	}

	/* Atomic allocations - we can't balance anything */
	if (!wait)
		goto nopage;

rebalance:
	cond_resched();

	/* We now go into synchronous reclaim */
985
	cpuset_memory_pressure_bump();
Linus Torvalds's avatar
Linus Torvalds committed
986 987 988 989
	p->flags |= PF_MEMALLOC;
	reclaim_state.reclaimed_slab = 0;
	p->reclaim_state = &reclaim_state;

Rohit Seth's avatar
Rohit Seth committed
990
	did_some_progress = try_to_free_pages(zonelist->zones, gfp_mask);
Linus Torvalds's avatar
Linus Torvalds committed
991 992 993 994 995 996 997

	p->reclaim_state = NULL;
	p->flags &= ~PF_MEMALLOC;

	cond_resched();

	if (likely(did_some_progress)) {
Rohit Seth's avatar
Rohit Seth committed
998 999 1000 1001
		page = get_page_from_freelist(gfp_mask, order,
						zonelist, alloc_flags);
		if (page)
			goto got_pg;
Linus Torvalds's avatar
Linus Torvalds committed
1002 1003 1004 1005 1006 1007 1008
	} else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
		/*
		 * Go through the zonelist yet one more time, keep
		 * very high watermark here, this is only to catch
		 * a parallel oom killing, we must fail if we're still
		 * under heavy pressure.
		 */
Rohit Seth's avatar
Rohit Seth committed
1009
		page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
1010
				zonelist, ALLOC_WMARK_HIGH|ALLOC_CPUSET);
Rohit Seth's avatar
Rohit Seth committed
1011 1012
		if (page)
			goto got_pg;
Linus Torvalds's avatar
Linus Torvalds committed
1013

1014
		out_of_memory(gfp_mask, order);
Linus Torvalds's avatar
Linus Torvalds committed
1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042
		goto restart;
	}

	/*
	 * Don't let big-order allocations loop unless the caller explicitly
	 * requests that.  Wait for some write requests to complete then retry.
	 *
	 * In this implementation, __GFP_REPEAT means __GFP_NOFAIL for order
	 * <= 3, but that may not be true in other implementations.
	 */
	do_retry = 0;
	if (!(gfp_mask & __GFP_NORETRY)) {
		if ((order <= 3) || (gfp_mask & __GFP_REPEAT))
			do_retry = 1;
		if (gfp_mask & __GFP_NOFAIL)
			do_retry = 1;
	}
	if (do_retry) {
		blk_congestion_wait(WRITE, HZ/50);
		goto rebalance;
	}

nopage:
	if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
		printk(KERN_WARNING "%s: page allocation failure."
			" order:%d, mode:0x%x\n",
			p->comm, order, gfp_mask);
		dump_stack();
Janet Morgan's avatar
Janet Morgan committed
1043
		show_mem();
Linus Torvalds's avatar
Linus Torvalds committed
1044 1045 1046 1047 1048 1049 1050 1051 1052 1053
	}
got_pg:
	return page;
}

EXPORT_SYMBOL(__alloc_pages);

/*
 * Common helper functions.
 */
1054
fastcall unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
Linus Torvalds's avatar
Linus Torvalds committed
1055 1056 1057 1058 1059 1060 1061 1062 1063 1064
{
	struct page * page;
	page = alloc_pages(gfp_mask, order);
	if (!page)
		return 0;
	return (unsigned long) page_address(page);
}

EXPORT_SYMBOL(__get_free_pages);

1065
fastcall unsigned long get_zeroed_page(gfp_t gfp_mask)
Linus Torvalds's avatar
Linus Torvalds committed
1066 1067 1068 1069 1070 1071 1072
{
	struct page * page;

	/*
	 * get_zeroed_page() returns a 32-bit address, which cannot represent
	 * a highmem page
	 */
Al Viro's avatar
Al Viro committed
1073
	BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
Linus Torvalds's avatar
Linus Torvalds committed
1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092

	page = alloc_pages(gfp_mask | __GFP_ZERO, 0);
	if (page)
		return (unsigned long) page_address(page);
	return 0;
}

EXPORT_SYMBOL(get_zeroed_page);

void __pagevec_free(struct pagevec *pvec)
{
	int i = pagevec_count(pvec);

	while (--i >= 0)
		free_hot_cold_page(pvec->pages[i], pvec->cold);
}

fastcall void __free_pages(struct page *page, unsigned int order)
{
Nick Piggin's avatar
Nick Piggin committed
1093
	if (put_page_testzero(page)) {
Linus Torvalds's avatar
Linus Torvalds committed
1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142
		if (order == 0)
			free_hot_page(page);
		else
			__free_pages_ok(page, order);
	}
}

EXPORT_SYMBOL(__free_pages);

fastcall void free_pages(unsigned long addr, unsigned int order)
{
	if (addr != 0) {
		BUG_ON(!virt_addr_valid((void *)addr));
		__free_pages(virt_to_page((void *)addr), order);
	}
}

EXPORT_SYMBOL(free_pages);

/*
 * Total amount of free (allocatable) RAM:
 */
unsigned int nr_free_pages(void)
{
	unsigned int sum = 0;
	struct zone *zone;

	for_each_zone(zone)
		sum += zone->free_pages;

	return sum;
}

EXPORT_SYMBOL(nr_free_pages);

#ifdef CONFIG_NUMA
unsigned int nr_free_pages_pgdat(pg_data_t *pgdat)
{
	unsigned int i, sum = 0;

	for (i = 0; i < MAX_NR_ZONES; i++)
		sum += pgdat->node_zones[i].free_pages;

	return sum;
}
#endif

static unsigned int nr_free_zone_pages(int offset)
{
1143 1144
	/* Just pick one node, since fallback list is circular */
	pg_data_t *pgdat = NODE_DATA(numa_node_id());
Linus Torvalds's avatar
Linus Torvalds committed
1145 1146
	unsigned int sum = 0;

1147 1148 1149
	struct zonelist *zonelist = pgdat->node_zonelists + offset;
	struct zone **zonep = zonelist->zones;
	struct zone *zone;
Linus Torvalds's avatar
Linus Torvalds committed
1150

1151 1152 1153 1154 1155
	for (zone = *zonep++; zone; zone = *zonep++) {
		unsigned long size = zone->present_pages;
		unsigned long high = zone->pages_high;
		if (size > high)
			sum += size - high;
Linus Torvalds's avatar
Linus Torvalds committed
1156 1157 1158 1159 1160 1161 1162 1163 1164 1165
	}

	return sum;
}

/*
 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
 */
unsigned int nr_free_buffer_pages(void)
{
Al Viro's avatar
Al Viro committed
1166
	return nr_free_zone_pages(gfp_zone(GFP_USER));
Linus Torvalds's avatar
Linus Torvalds committed
1167 1168 1169 1170 1171 1172 1173
}

/*
 * Amount of free RAM allocatable within all zones
 */
unsigned int nr_free_pagecache_pages(void)
{
Al Viro's avatar
Al Viro committed
1174
	return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER));
Linus Torvalds's avatar
Linus Torvalds committed
1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211
}

#ifdef CONFIG_HIGHMEM
unsigned int nr_free_highpages (void)
{
	pg_data_t *pgdat;
	unsigned int pages = 0;

	for_each_pgdat(pgdat)
		pages += pgdat->node_zones[ZONE_HIGHMEM].free_pages;

	return pages;
}
#endif

#ifdef CONFIG_NUMA
static void show_node(struct zone *zone)
{
	printk("Node %d ", zone->zone_pgdat->node_id);
}
#else
#define show_node(zone)	do { } while (0)
#endif

/*
 * Accumulate the page_state information across all CPUs.
 * The result is unavoidably approximate - it can change
 * during and after execution of this function.
 */
static DEFINE_PER_CPU(struct page_state, page_states) = {0};

atomic_t nr_pagecache = ATOMIC_INIT(0);
EXPORT_SYMBOL(nr_pagecache);
#ifdef CONFIG_SMP
DEFINE_PER_CPU(long, nr_pagecache_local) = 0;
#endif

Nick Piggin's avatar
Nick Piggin committed
1212
static void __get_page_state(struct page_state *ret, int nr, cpumask_t *cpumask)
Linus Torvalds's avatar
Linus Torvalds committed
1213 1214 1215
{
	int cpu = 0;

1216
	memset(ret, 0, nr * sizeof(unsigned long));
1217
	cpus_and(*cpumask, *cpumask, cpu_online_map);
Linus Torvalds's avatar
Linus Torvalds committed
1218

1219
	cpu = first_cpu(*cpumask);
Linus Torvalds's avatar
Linus Torvalds committed
1220 1221 1222
	while (cpu < NR_CPUS) {
		unsigned long *in, *out, off;

1223 1224 1225
		if (!cpu_isset(cpu, *cpumask))
			continue;

Linus Torvalds's avatar
Linus Torvalds committed
1226 1227
		in = (unsigned long *)&per_cpu(page_states, cpu);

1228
		cpu = next_cpu(cpu, *cpumask);
Linus Torvalds's avatar
Linus Torvalds committed
1229

1230
		if (likely(cpu < NR_CPUS))
Linus Torvalds's avatar
Linus Torvalds committed
1231 1232 1233 1234 1235 1236 1237 1238
			prefetch(&per_cpu(page_states, cpu));

		out = (unsigned long *)ret;
		for (off = 0; off < nr; off++)
			*out++ += *in++;
	}
}

1239 1240 1241 1242 1243 1244 1245