page_alloc.c 186 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
/*
 *  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>
22
#include <linux/jiffies.h>
Linus Torvalds's avatar
Linus Torvalds committed
23
#include <linux/bootmem.h>
24
#include <linux/memblock.h>
Linus Torvalds's avatar
Linus Torvalds committed
25
#include <linux/compiler.h>
26
#include <linux/kernel.h>
27
#include <linux/kmemcheck.h>
28
#include <linux/kasan.h>
Linus Torvalds's avatar
Linus Torvalds committed
29 30 31 32 33
#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/pagevec.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
34
#include <linux/ratelimit.h>
35
#include <linux/oom.h>
Linus Torvalds's avatar
Linus Torvalds committed
36 37 38 39 40
#include <linux/notifier.h>
#include <linux/topology.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
41
#include <linux/memory_hotplug.h>
Linus Torvalds's avatar
Linus Torvalds committed
42 43
#include <linux/nodemask.h>
#include <linux/vmalloc.h>
44
#include <linux/vmstat.h>
45
#include <linux/mempolicy.h>
46
#include <linux/stop_machine.h>
47 48
#include <linux/sort.h>
#include <linux/pfn.h>
49
#include <linux/backing-dev.h>
50
#include <linux/fault-inject.h>
51
#include <linux/page-isolation.h>
52
#include <linux/page_ext.h>
53
#include <linux/debugobjects.h>
54
#include <linux/kmemleak.h>
55
#include <linux/compaction.h>
56
#include <trace/events/kmem.h>
57
#include <linux/prefetch.h>
58
#include <linux/mm_inline.h>
59
#include <linux/migrate.h>
60
#include <linux/page_ext.h>
61
#include <linux/hugetlb.h>
62
#include <linux/sched/rt.h>
63
#include <linux/page_owner.h>
Linus Torvalds's avatar
Linus Torvalds committed
64

65
#include <asm/sections.h>
Linus Torvalds's avatar
Linus Torvalds committed
66
#include <asm/tlbflush.h>
67
#include <asm/div64.h>
Linus Torvalds's avatar
Linus Torvalds committed
68 69
#include "internal.h"

70 71
/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
static DEFINE_MUTEX(pcp_batch_high_lock);
72
#define MIN_PERCPU_PAGELIST_FRACTION	(8)
73

74 75 76 77 78
#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
DEFINE_PER_CPU(int, numa_node);
EXPORT_PER_CPU_SYMBOL(numa_node);
#endif

79 80 81 82 83 84 85 86 87
#ifdef CONFIG_HAVE_MEMORYLESS_NODES
/*
 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
 * defined in <linux/topology.h>.
 */
DEFINE_PER_CPU(int, _numa_mem_);		/* Kernel "local memory" node */
EXPORT_PER_CPU_SYMBOL(_numa_mem_);
88
int _node_numa_mem_[MAX_NUMNODES];
89 90
#endif

Linus Torvalds's avatar
Linus Torvalds committed
91
/*
92
 * Array of node states.
Linus Torvalds's avatar
Linus Torvalds committed
93
 */
94 95 96 97 98 99 100
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 } },
101 102 103
#endif
#ifdef CONFIG_MOVABLE_NODE
	[N_MEMORY] = { { [0] = 1UL } },
104 105 106 107 108 109
#endif
	[N_CPU] = { { [0] = 1UL } },
#endif	/* NUMA */
};
EXPORT_SYMBOL(node_states);

110 111 112
/* Protect totalram_pages and zone->managed_pages */
static DEFINE_SPINLOCK(managed_page_count_lock);

113
unsigned long totalram_pages __read_mostly;
114
unsigned long totalreserve_pages __read_mostly;
115
unsigned long totalcma_pages __read_mostly;
116 117 118 119 120 121 122 123
/*
 * When calculating the number of globally allowed dirty pages, there
 * is a certain number of per-zone reserves that should not be
 * considered dirtyable memory.  This is the sum of those reserves
 * over all existing zones that contribute dirtyable memory.
 */
unsigned long dirty_balance_reserve __read_mostly;

124
int percpu_pagelist_fraction;
125
gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
Linus Torvalds's avatar
Linus Torvalds committed
126

127 128 129 130 131 132 133 134 135
#ifdef CONFIG_PM_SLEEP
/*
 * The following functions are used by the suspend/hibernate code to temporarily
 * change gfp_allowed_mask in order to avoid using I/O during memory allocations
 * while devices are suspended.  To avoid races with the suspend/hibernate code,
 * they should always be called with pm_mutex held (gfp_allowed_mask also should
 * only be modified with pm_mutex held, unless the suspend/hibernate code is
 * guaranteed not to run in parallel with that modification).
 */
136 137 138 139

static gfp_t saved_gfp_mask;

void pm_restore_gfp_mask(void)
140 141
{
	WARN_ON(!mutex_is_locked(&pm_mutex));
142 143 144 145
	if (saved_gfp_mask) {
		gfp_allowed_mask = saved_gfp_mask;
		saved_gfp_mask = 0;
	}
146 147
}

148
void pm_restrict_gfp_mask(void)
149 150
{
	WARN_ON(!mutex_is_locked(&pm_mutex));
151 152 153
	WARN_ON(saved_gfp_mask);
	saved_gfp_mask = gfp_allowed_mask;
	gfp_allowed_mask &= ~GFP_IOFS;
154
}
155 156 157 158 159 160 161

bool pm_suspended_storage(void)
{
	if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS)
		return false;
	return true;
}
162 163
#endif /* CONFIG_PM_SLEEP */

164 165 166 167
#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
int pageblock_order __read_mostly;
#endif

168
static void __free_pages_ok(struct page *page, unsigned int order);
169

Linus Torvalds's avatar
Linus Torvalds committed
170 171 172 173 174 175
/*
 * 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
Yaowei Bai's avatar
Yaowei Bai committed
176
 *	HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA
177 178 179
 *
 * 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
180
 */
181
int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
182
#ifdef CONFIG_ZONE_DMA
183
	 256,
184
#endif
185
#ifdef CONFIG_ZONE_DMA32
186
	 256,
187
#endif
188
#ifdef CONFIG_HIGHMEM
Mel Gorman's avatar
Mel Gorman committed
189
	 32,
190
#endif
Mel Gorman's avatar
Mel Gorman committed
191
	 32,
192
};
Linus Torvalds's avatar
Linus Torvalds committed
193 194 195

EXPORT_SYMBOL(totalram_pages);

196
static char * const zone_names[MAX_NR_ZONES] = {
197
#ifdef CONFIG_ZONE_DMA
198
	 "DMA",
199
#endif
200
#ifdef CONFIG_ZONE_DMA32
201
	 "DMA32",
202
#endif
203
	 "Normal",
204
#ifdef CONFIG_HIGHMEM
Mel Gorman's avatar
Mel Gorman committed
205
	 "HighMem",
206
#endif
Mel Gorman's avatar
Mel Gorman committed
207
	 "Movable",
208 209
};

Linus Torvalds's avatar
Linus Torvalds committed
210
int min_free_kbytes = 1024;
211
int user_min_free_kbytes = -1;
Linus Torvalds's avatar
Linus Torvalds committed
212

213 214
static unsigned long __meminitdata nr_kernel_pages;
static unsigned long __meminitdata nr_all_pages;
215
static unsigned long __meminitdata dma_reserve;
Linus Torvalds's avatar
Linus Torvalds committed
216

Tejun Heo's avatar
Tejun Heo committed
217 218 219 220 221 222 223 224 225 226 227
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
static unsigned long __initdata required_kernelcore;
static unsigned long __initdata required_movablecore;
static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];

/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
int movable_zone;
EXPORT_SYMBOL(movable_zone);
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
228

Miklos Szeredi's avatar
Miklos Szeredi committed
229 230
#if MAX_NUMNODES > 1
int nr_node_ids __read_mostly = MAX_NUMNODES;
231
int nr_online_nodes __read_mostly = 1;
Miklos Szeredi's avatar
Miklos Szeredi committed
232
EXPORT_SYMBOL(nr_node_ids);
233
EXPORT_SYMBOL(nr_online_nodes);
Miklos Szeredi's avatar
Miklos Szeredi committed
234 235
#endif

236 237
int page_group_by_mobility_disabled __read_mostly;

238
void set_pageblock_migratetype(struct page *page, int migratetype)
239
{
240 241
	if (unlikely(page_group_by_mobility_disabled &&
		     migratetype < MIGRATE_PCPTYPES))
242 243
		migratetype = MIGRATE_UNMOVABLE;

244 245 246 247
	set_pageblock_flags_group(page, (unsigned long)migratetype,
					PB_migrate, PB_migrate_end);
}

Nick Piggin's avatar
Nick Piggin committed
248
#ifdef CONFIG_DEBUG_VM
249
static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
250
{
251 252 253
	int ret = 0;
	unsigned seq;
	unsigned long pfn = page_to_pfn(page);
254
	unsigned long sp, start_pfn;
255

256 257
	do {
		seq = zone_span_seqbegin(zone);
258 259
		start_pfn = zone->zone_start_pfn;
		sp = zone->spanned_pages;
260
		if (!zone_spans_pfn(zone, pfn))
261 262 263
			ret = 1;
	} while (zone_span_seqretry(zone, seq));

264
	if (ret)
265 266 267
		pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
			pfn, zone_to_nid(zone), zone->name,
			start_pfn, start_pfn + sp);
268

269
	return ret;
270 271 272 273
}

static int page_is_consistent(struct zone *zone, struct page *page)
{
274
	if (!pfn_valid_within(page_to_pfn(page)))
275
		return 0;
Linus Torvalds's avatar
Linus Torvalds committed
276
	if (zone != page_zone(page))
277 278 279 280 281 282 283 284 285 286
		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
287
		return 1;
288 289 290
	if (!page_is_consistent(zone, page))
		return 1;

Linus Torvalds's avatar
Linus Torvalds committed
291 292
	return 0;
}
Nick Piggin's avatar
Nick Piggin committed
293 294 295 296 297 298 299
#else
static inline int bad_range(struct zone *zone, struct page *page)
{
	return 0;
}
#endif

300 301
static void bad_page(struct page *page, const char *reason,
		unsigned long bad_flags)
Linus Torvalds's avatar
Linus Torvalds committed
302
{
303 304 305 306
	static unsigned long resume;
	static unsigned long nr_shown;
	static unsigned long nr_unshown;

307 308
	/* Don't complain about poisoned pages */
	if (PageHWPoison(page)) {
309
		page_mapcount_reset(page); /* remove PageBuddy */
310 311 312
		return;
	}

313 314 315 316 317 318 319 320 321 322
	/*
	 * Allow a burst of 60 reports, then keep quiet for that minute;
	 * or allow a steady drip of one report per second.
	 */
	if (nr_shown == 60) {
		if (time_before(jiffies, resume)) {
			nr_unshown++;
			goto out;
		}
		if (nr_unshown) {
323 324
			printk(KERN_ALERT
			      "BUG: Bad page state: %lu messages suppressed\n",
325 326 327 328 329 330 331 332
				nr_unshown);
			nr_unshown = 0;
		}
		nr_shown = 0;
	}
	if (nr_shown++ == 0)
		resume = jiffies + 60 * HZ;

333
	printk(KERN_ALERT "BUG: Bad page state in process %s  pfn:%05lx\n",
334
		current->comm, page_to_pfn(page));
335
	dump_page_badflags(page, reason, bad_flags);
336

337
	print_modules();
Linus Torvalds's avatar
Linus Torvalds committed
338
	dump_stack();
339
out:
340
	/* Leave bad fields for debug, except PageBuddy could make trouble */
341
	page_mapcount_reset(page); /* remove PageBuddy */
342
	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
Linus Torvalds's avatar
Linus Torvalds committed
343 344 345 346 347 348 349 350 351
}

/*
 * 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".
 *
352 353
 * All pages have PG_compound set.  All tail pages have their ->first_page
 * pointing at the head page.
Linus Torvalds's avatar
Linus Torvalds committed
354
 *
355 356 357
 * 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
358
 */
359 360 361

static void free_compound_page(struct page *page)
{
362
	__free_pages_ok(page, compound_order(page));
363 364
}

365
void prep_compound_page(struct page *page, unsigned long order)
366 367 368 369 370 371 372 373 374
{
	int i;
	int nr_pages = 1 << order;

	set_compound_page_dtor(page, free_compound_page);
	set_compound_order(page, order);
	__SetPageHead(page);
	for (i = 1; i < nr_pages; i++) {
		struct page *p = page + i;
375
		set_page_count(p, 0);
376
		p->first_page = page;
David Rientjes's avatar
David Rientjes committed
377 378 379
		/* Make sure p->first_page is always valid for PageTail() */
		smp_wmb();
		__SetPageTail(p);
380 381 382
	}
}

383 384
#ifdef CONFIG_DEBUG_PAGEALLOC
unsigned int _debug_guardpage_minorder;
385
bool _debug_pagealloc_enabled __read_mostly;
386 387
bool _debug_guardpage_enabled __read_mostly;

388 389 390 391 392 393 394 395 396 397 398 399
static int __init early_debug_pagealloc(char *buf)
{
	if (!buf)
		return -EINVAL;

	if (strcmp(buf, "on") == 0)
		_debug_pagealloc_enabled = true;

	return 0;
}
early_param("debug_pagealloc", early_debug_pagealloc);

400 401
static bool need_debug_guardpage(void)
{
402 403 404 405
	/* If we don't use debug_pagealloc, we don't need guard page */
	if (!debug_pagealloc_enabled())
		return false;

406 407 408 409 410
	return true;
}

static void init_debug_guardpage(void)
{
411 412 413
	if (!debug_pagealloc_enabled())
		return;

414 415 416 417 418 419 420
	_debug_guardpage_enabled = true;
}

struct page_ext_operations debug_guardpage_ops = {
	.need = need_debug_guardpage,
	.init = init_debug_guardpage,
};
421 422 423 424 425 426 427 428 429 430 431 432 433 434 435

static int __init debug_guardpage_minorder_setup(char *buf)
{
	unsigned long res;

	if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
		printk(KERN_ERR "Bad debug_guardpage_minorder value\n");
		return 0;
	}
	_debug_guardpage_minorder = res;
	printk(KERN_INFO "Setting debug_guardpage_minorder to %lu\n", res);
	return 0;
}
__setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup);

436 437
static inline void set_page_guard(struct zone *zone, struct page *page,
				unsigned int order, int migratetype)
438
{
439 440 441 442 443 444 445 446
	struct page_ext *page_ext;

	if (!debug_guardpage_enabled())
		return;

	page_ext = lookup_page_ext(page);
	__set_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);

447 448 449 450
	INIT_LIST_HEAD(&page->lru);
	set_page_private(page, order);
	/* Guard pages are not available for any usage */
	__mod_zone_freepage_state(zone, -(1 << order), migratetype);
451 452
}

453 454
static inline void clear_page_guard(struct zone *zone, struct page *page,
				unsigned int order, int migratetype)
455
{
456 457 458 459 460 461 462 463
	struct page_ext *page_ext;

	if (!debug_guardpage_enabled())
		return;

	page_ext = lookup_page_ext(page);
	__clear_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);

464 465 466
	set_page_private(page, 0);
	if (!is_migrate_isolate(migratetype))
		__mod_zone_freepage_state(zone, (1 << order), migratetype);
467 468
}
#else
469
struct page_ext_operations debug_guardpage_ops = { NULL, };
470 471 472 473
static inline void set_page_guard(struct zone *zone, struct page *page,
				unsigned int order, int migratetype) {}
static inline void clear_page_guard(struct zone *zone, struct page *page,
				unsigned int order, int migratetype) {}
474 475
#endif

476
static inline void set_page_order(struct page *page, unsigned int order)
477
{
478
	set_page_private(page, order);
479
	__SetPageBuddy(page);
Linus Torvalds's avatar
Linus Torvalds committed
480 481 482 483
}

static inline void rmv_page_order(struct page *page)
{
484
	__ClearPageBuddy(page);
485
	set_page_private(page, 0);
Linus Torvalds's avatar
Linus Torvalds committed
486 487 488 489 490
}

/*
 * 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
491
 * (a) the buddy is not in a hole &&
492
 * (b) the buddy is in the buddy system &&
493 494
 * (c) a page and its buddy have the same order &&
 * (d) a page and its buddy are in the same zone.
495
 *
496 497 498 499
 * For recording whether a page is in the buddy system, we set ->_mapcount
 * PAGE_BUDDY_MAPCOUNT_VALUE.
 * Setting, clearing, and testing _mapcount PAGE_BUDDY_MAPCOUNT_VALUE is
 * serialized by zone->lock.
Linus Torvalds's avatar
Linus Torvalds committed
500
 *
501
 * For recording page's order, we use page_private(page).
Linus Torvalds's avatar
Linus Torvalds committed
502
 */
503
static inline int page_is_buddy(struct page *page, struct page *buddy,
504
							unsigned int order)
Linus Torvalds's avatar
Linus Torvalds committed
505
{
506
	if (!pfn_valid_within(page_to_pfn(buddy)))
Nick Piggin's avatar
Nick Piggin committed
507 508
		return 0;

509
	if (page_is_guard(buddy) && page_order(buddy) == order) {
510 511 512
		if (page_zone_id(page) != page_zone_id(buddy))
			return 0;

513 514
		VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);

515 516 517
		return 1;
	}

518
	if (PageBuddy(buddy) && page_order(buddy) == order) {
519 520 521 522 523 524 525 526
		/*
		 * zone check is done late to avoid uselessly
		 * calculating zone/node ids for pages that could
		 * never merge.
		 */
		if (page_zone_id(page) != page_zone_id(buddy))
			return 0;

527 528
		VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);

529
		return 1;
530
	}
531
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
532 533 534 535 536 537 538 539 540 541 542 543 544 545 546
}

/*
 * 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
547 548 549
 * free pages of length of (1 << order) and marked with _mapcount
 * PAGE_BUDDY_MAPCOUNT_VALUE. Page's order is recorded in page_private(page)
 * field.
Linus Torvalds's avatar
Linus Torvalds committed
550
 * So when we are allocating or freeing one, we can derive the state of the
551 552
 * other.  That is, if we allocate a small block, and both were
 * free, the remainder of the region must be split into blocks.
Linus Torvalds's avatar
Linus Torvalds committed
553
 * If a block is freed, and its buddy is also free, then this
554
 * triggers coalescing into a block of larger size.
Linus Torvalds's avatar
Linus Torvalds committed
555
 *
556
 * -- nyc
Linus Torvalds's avatar
Linus Torvalds committed
557 558
 */

Nick Piggin's avatar
Nick Piggin committed
559
static inline void __free_one_page(struct page *page,
560
		unsigned long pfn,
561 562
		struct zone *zone, unsigned int order,
		int migratetype)
Linus Torvalds's avatar
Linus Torvalds committed
563 564
{
	unsigned long page_idx;
565
	unsigned long combined_idx;
566
	unsigned long uninitialized_var(buddy_idx);
567
	struct page *buddy;
568
	int max_order = MAX_ORDER;
Linus Torvalds's avatar
Linus Torvalds committed
569

570
	VM_BUG_ON(!zone_is_initialized(zone));
571
	VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
Linus Torvalds's avatar
Linus Torvalds committed
572

573
	VM_BUG_ON(migratetype == -1);
574 575 576 577 578 579 580 581 582
	if (is_migrate_isolate(migratetype)) {
		/*
		 * We restrict max order of merging to prevent merge
		 * between freepages on isolate pageblock and normal
		 * pageblock. Without this, pageblock isolation
		 * could cause incorrect freepage accounting.
		 */
		max_order = min(MAX_ORDER, pageblock_order + 1);
	} else {
583
		__mod_zone_freepage_state(zone, 1 << order, migratetype);
584
	}
585

586
	page_idx = pfn & ((1 << max_order) - 1);
Linus Torvalds's avatar
Linus Torvalds committed
587

588 589
	VM_BUG_ON_PAGE(page_idx & ((1 << order) - 1), page);
	VM_BUG_ON_PAGE(bad_range(zone, page), page);
Linus Torvalds's avatar
Linus Torvalds committed
590

591
	while (order < max_order - 1) {
592 593
		buddy_idx = __find_buddy_index(page_idx, order);
		buddy = page + (buddy_idx - page_idx);
594
		if (!page_is_buddy(page, buddy, order))
595
			break;
596 597 598 599 600
		/*
		 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
		 * merge with it and move up one order.
		 */
		if (page_is_guard(buddy)) {
601
			clear_page_guard(zone, buddy, order, migratetype);
602 603 604 605 606
		} else {
			list_del(&buddy->lru);
			zone->free_area[order].nr_free--;
			rmv_page_order(buddy);
		}
607
		combined_idx = buddy_idx & page_idx;
Linus Torvalds's avatar
Linus Torvalds committed
608 609 610 611 612
		page = page + (combined_idx - page_idx);
		page_idx = combined_idx;
		order++;
	}
	set_page_order(page, order);
613 614 615 616 617 618 619 620 621

	/*
	 * If this is not the largest possible page, check if the buddy
	 * of the next-highest order is free. If it is, it's possible
	 * that pages are being freed that will coalesce soon. In case,
	 * that is happening, add the free page to the tail of the list
	 * so it's less likely to be used soon and more likely to be merged
	 * as a higher order page
	 */
622
	if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
623
		struct page *higher_page, *higher_buddy;
624 625 626
		combined_idx = buddy_idx & page_idx;
		higher_page = page + (combined_idx - page_idx);
		buddy_idx = __find_buddy_index(combined_idx, order + 1);
627
		higher_buddy = higher_page + (buddy_idx - combined_idx);
628 629 630 631 632 633 634 635 636
		if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
			list_add_tail(&page->lru,
				&zone->free_area[order].free_list[migratetype]);
			goto out;
		}
	}

	list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
out:
Linus Torvalds's avatar
Linus Torvalds committed
637 638 639
	zone->free_area[order].nr_free++;
}

640
static inline int free_pages_check(struct page *page)
Linus Torvalds's avatar
Linus Torvalds committed
641
{
642
	const char *bad_reason = NULL;
643 644 645 646 647 648 649 650 651 652 653 654
	unsigned long bad_flags = 0;

	if (unlikely(page_mapcount(page)))
		bad_reason = "nonzero mapcount";
	if (unlikely(page->mapping != NULL))
		bad_reason = "non-NULL mapping";
	if (unlikely(atomic_read(&page->_count) != 0))
		bad_reason = "nonzero _count";
	if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
		bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
		bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
	}
655 656 657 658
#ifdef CONFIG_MEMCG
	if (unlikely(page->mem_cgroup))
		bad_reason = "page still charged to cgroup";
#endif
659 660
	if (unlikely(bad_reason)) {
		bad_page(page, bad_reason, bad_flags);
661
		return 1;
662
	}
663
	page_cpupid_reset_last(page);
664 665 666
	if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
		page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
667 668 669
}

/*
670
 * Frees a number of pages from the PCP lists
Linus Torvalds's avatar
Linus Torvalds committed
671
 * Assumes all pages on list are in same zone, and of same order.
672
 * count is the number of pages to free.
Linus Torvalds's avatar
Linus Torvalds committed
673 674 675 676 677 678 679
 *
 * 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.
 */
680 681
static void free_pcppages_bulk(struct zone *zone, int count,
					struct per_cpu_pages *pcp)
Linus Torvalds's avatar
Linus Torvalds committed
682
{
683
	int migratetype = 0;
684
	int batch_free = 0;
685
	int to_free = count;
686
	unsigned long nr_scanned;
687

Nick Piggin's avatar
Nick Piggin committed
688
	spin_lock(&zone->lock);
689 690 691
	nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED);
	if (nr_scanned)
		__mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
692

693
	while (to_free) {
Nick Piggin's avatar
Nick Piggin committed
694
		struct page *page;
695 696 697
		struct list_head *list;

		/*
698 699 700 701 702
		 * Remove pages from lists in a round-robin fashion. A
		 * batch_free count is maintained that is incremented when an
		 * empty list is encountered.  This is so more pages are freed
		 * off fuller lists instead of spinning excessively around empty
		 * lists
703 704
		 */
		do {
705
			batch_free++;
706 707 708 709
			if (++migratetype == MIGRATE_PCPTYPES)
				migratetype = 0;
			list = &pcp->lists[migratetype];
		} while (list_empty(list));
Nick Piggin's avatar
Nick Piggin committed
710

711 712 713 714
		/* This is the only non-empty list. Free them all. */
		if (batch_free == MIGRATE_PCPTYPES)
			batch_free = to_free;

715
		do {
716 717
			int mt;	/* migratetype of the to-be-freed page */

718 719 720
			page = list_entry(list->prev, struct page, lru);
			/* must delete as __free_one_page list manipulates */
			list_del(&page->lru);
721
			mt = get_freepage_migratetype(page);
722
			if (unlikely(has_isolate_pageblock(zone)))
723 724
				mt = get_pageblock_migratetype(page);

725
			/* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
726
			__free_one_page(page, page_to_pfn(page), zone, 0, mt);
727
			trace_mm_page_pcpu_drain(page, 0, mt);
728
		} while (--to_free && --batch_free && !list_empty(list));
Linus Torvalds's avatar
Linus Torvalds committed
729
	}
Nick Piggin's avatar
Nick Piggin committed
730
	spin_unlock(&zone->lock);
Linus Torvalds's avatar
Linus Torvalds committed
731 732
}

733 734
static void free_one_page(struct zone *zone,
				struct page *page, unsigned long pfn,
735
				unsigned int order,
736
				int migratetype)
Linus Torvalds's avatar
Linus Torvalds committed
737
{
738
	unsigned long nr_scanned;
739
	spin_lock(&zone->lock);
740 741 742
	nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED);
	if (nr_scanned)
		__mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
743

744 745 746 747
	if (unlikely(has_isolate_pageblock(zone) ||
		is_migrate_isolate(migratetype))) {
		migratetype = get_pfnblock_migratetype(page, pfn);
	}
748
	__free_one_page(page, pfn, zone, order, migratetype);
749
	spin_unlock(&zone->lock);
Nick Piggin's avatar
Nick Piggin committed
750 751
}

752 753 754 755 756 757 758 759 760 761 762 763 764 765 766
static int free_tail_pages_check(struct page *head_page, struct page *page)
{
	if (!IS_ENABLED(CONFIG_DEBUG_VM))
		return 0;
	if (unlikely(!PageTail(page))) {
		bad_page(page, "PageTail not set", 0);
		return 1;
	}
	if (unlikely(page->first_page != head_page)) {
		bad_page(page, "first_page not consistent", 0);
		return 1;
	}
	return 0;
}

767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810
static void __meminit __init_single_page(struct page *page, unsigned long pfn,
				unsigned long zone, int nid)
{
	struct zone *z = &NODE_DATA(nid)->node_zones[zone];

	set_page_links(page, zone, nid, pfn);
	mminit_verify_page_links(page, zone, nid, pfn);
	init_page_count(page);
	page_mapcount_reset(page);
	page_cpupid_reset_last(page);

	/*
	 * Mark the block movable so that blocks are reserved for
	 * movable at startup. This will force kernel allocations
	 * to reserve their blocks rather than leaking throughout
	 * the address space during boot when many long-lived
	 * kernel allocations are made. Later some blocks near
	 * the start are marked MIGRATE_RESERVE by
	 * setup_zone_migrate_reserve()
	 *
	 * bitmap is created for zone's valid pfn range. but memmap
	 * can be created for invalid pages (for alignment)
	 * check here not to call set_pageblock_migratetype() against
	 * pfn out of zone.
	 */
	if ((z->zone_start_pfn <= pfn)
	    && (pfn < zone_end_pfn(z))
	    && !(pfn & (pageblock_nr_pages - 1)))
		set_pageblock_migratetype(page, MIGRATE_MOVABLE);

	INIT_LIST_HEAD(&page->lru);
#ifdef WANT_PAGE_VIRTUAL
	/* The shift won't overflow because ZONE_NORMAL is below 4G. */
	if (!is_highmem_idx(zone))
		set_page_address(page, __va(pfn << PAGE_SHIFT));
#endif
}

static void __meminit __init_single_pfn(unsigned long pfn, unsigned long zone,
					int nid)
{
	return __init_single_page(pfn_to_page(pfn), pfn, zone, nid);
}

811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826
/*
 * Initialised pages do not have PageReserved set. This function is
 * called for each range allocated by the bootmem allocator and
 * marks the pages PageReserved. The remaining valid pages are later
 * sent to the buddy page allocator.
 */
void reserve_bootmem_region(unsigned long start, unsigned long end)
{
	unsigned long start_pfn = PFN_DOWN(start);
	unsigned long end_pfn = PFN_UP(end);

	for (; start_pfn < end_pfn; start_pfn++)
		if (pfn_valid(start_pfn))
			SetPageReserved(pfn_to_page(start_pfn));
}

827
static bool free_pages_prepare(struct page *page, unsigned int order)
Nick Piggin's avatar
Nick Piggin committed
828
{
829 830
	bool compound = PageCompound(page);
	int i, bad = 0;
Linus Torvalds's avatar
Linus Torvalds committed
831

832
	VM_BUG_ON_PAGE(PageTail(page), page);
833
	VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
834

835
	trace_mm_page_free(page, order);
836
	kmemcheck_free_shadow(page, order);
837
	kasan_free_pages(page, order);
838

Andrea Arcangeli's avatar
Andrea Arcangeli committed
839 840
	if (PageAnon(page))
		page->mapping = NULL;
841 842 843 844
	bad += free_pages_check(page);
	for (i = 1; i < (1 << order); i++) {
		if (compound)
			bad += free_tail_pages_check(page, page + i);
Andrea Arcangeli's avatar
Andrea Arcangeli committed
845
		bad += free_pages_check(page + i);
846
	}
847
	if (bad)
848
		return false;
849

850 851
	reset_page_owner(page, order);

852
	if (!PageHighMem(page)) {
853 854
		debug_check_no_locks_freed(page_address(page),
					   PAGE_SIZE << order);
855 856 857
		debug_check_no_obj_freed(page_address(page),
					   PAGE_SIZE << order);
	}
Nick Piggin's avatar
Nick Piggin committed
858
	arch_free_page(page, order);
Nick Piggin's avatar
Nick Piggin committed
859
	kernel_map_pages(page, 1 << order, 0);
Nick Piggin's avatar
Nick Piggin committed
860

861 862 863 864 865 866
	return true;
}

static void __free_pages_ok(struct page *page, unsigned int order)
{
	unsigned long flags;
867
	int migratetype;
868
	unsigned long pfn = page_to_pfn(page);
869 870 871 872

	if (!free_pages_prepare(page, order))
		return;

873
	migratetype = get_pfnblock_migratetype(page, pfn);
Nick Piggin's avatar
Nick Piggin committed
874
	local_irq_save(flags);
875
	__count_vm_events(PGFREE, 1 << order);
876
	set_freepage_migratetype(page, migratetype);
877
	free_one_page(page_zone(page), page, pfn, order, migratetype);
Nick Piggin's avatar
Nick Piggin committed
878
	local_irq_restore(flags);
Linus Torvalds's avatar
Linus Torvalds committed
879 880
}

881 882
void __init __free_pages_bootmem(struct page *page, unsigned long pfn,
							unsigned int order)
883
{
884
	unsigned int nr_pages = 1 << order;
885
	struct page *p = page;
886
	unsigned int loop;
887

888 889 890
	prefetchw(p);
	for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
		prefetchw(p + 1);
891 892
		__ClearPageReserved(p);
		set_page_count(p, 0);
893
	}
894 895
	__ClearPageReserved(p);
	set_page_count(p, 0);
896

897
	page_zone(page)->managed_pages += nr_pages;
898 899
	set_page_refcounted(page);
	__free_pages(page, order);
900 901
}

902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944