xref: /openbmc/linux/mm/page_alloc.c (revision 09b35b41)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/mm/page_alloc.c
4  *
5  *  Manages the free list, the system allocates free pages here.
6  *  Note that kmalloc() lives in slab.c
7  *
8  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
9  *  Swap reorganised 29.12.95, Stephen Tweedie
10  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
11  *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
12  *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
13  *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
14  *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
15  *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
16  */
17 
18 #include <linux/stddef.h>
19 #include <linux/mm.h>
20 #include <linux/highmem.h>
21 #include <linux/swap.h>
22 #include <linux/interrupt.h>
23 #include <linux/pagemap.h>
24 #include <linux/jiffies.h>
25 #include <linux/memblock.h>
26 #include <linux/compiler.h>
27 #include <linux/kernel.h>
28 #include <linux/kasan.h>
29 #include <linux/module.h>
30 #include <linux/suspend.h>
31 #include <linux/pagevec.h>
32 #include <linux/blkdev.h>
33 #include <linux/slab.h>
34 #include <linux/ratelimit.h>
35 #include <linux/oom.h>
36 #include <linux/topology.h>
37 #include <linux/sysctl.h>
38 #include <linux/cpu.h>
39 #include <linux/cpuset.h>
40 #include <linux/memory_hotplug.h>
41 #include <linux/nodemask.h>
42 #include <linux/vmalloc.h>
43 #include <linux/vmstat.h>
44 #include <linux/mempolicy.h>
45 #include <linux/memremap.h>
46 #include <linux/stop_machine.h>
47 #include <linux/random.h>
48 #include <linux/sort.h>
49 #include <linux/pfn.h>
50 #include <linux/backing-dev.h>
51 #include <linux/fault-inject.h>
52 #include <linux/page-isolation.h>
53 #include <linux/debugobjects.h>
54 #include <linux/kmemleak.h>
55 #include <linux/compaction.h>
56 #include <trace/events/kmem.h>
57 #include <trace/events/oom.h>
58 #include <linux/prefetch.h>
59 #include <linux/mm_inline.h>
60 #include <linux/migrate.h>
61 #include <linux/hugetlb.h>
62 #include <linux/sched/rt.h>
63 #include <linux/sched/mm.h>
64 #include <linux/page_owner.h>
65 #include <linux/kthread.h>
66 #include <linux/memcontrol.h>
67 #include <linux/ftrace.h>
68 #include <linux/lockdep.h>
69 #include <linux/nmi.h>
70 #include <linux/psi.h>
71 
72 #include <asm/sections.h>
73 #include <asm/tlbflush.h>
74 #include <asm/div64.h>
75 #include "internal.h"
76 #include "shuffle.h"
77 
78 /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
79 static DEFINE_MUTEX(pcp_batch_high_lock);
80 #define MIN_PERCPU_PAGELIST_FRACTION	(8)
81 
82 #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
83 DEFINE_PER_CPU(int, numa_node);
84 EXPORT_PER_CPU_SYMBOL(numa_node);
85 #endif
86 
87 DEFINE_STATIC_KEY_TRUE(vm_numa_stat_key);
88 
89 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
90 /*
91  * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
92  * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
93  * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
94  * defined in <linux/topology.h>.
95  */
96 DEFINE_PER_CPU(int, _numa_mem_);		/* Kernel "local memory" node */
97 EXPORT_PER_CPU_SYMBOL(_numa_mem_);
98 int _node_numa_mem_[MAX_NUMNODES];
99 #endif
100 
101 /* work_structs for global per-cpu drains */
102 struct pcpu_drain {
103 	struct zone *zone;
104 	struct work_struct work;
105 };
106 DEFINE_MUTEX(pcpu_drain_mutex);
107 DEFINE_PER_CPU(struct pcpu_drain, pcpu_drain);
108 
109 #ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
110 volatile unsigned long latent_entropy __latent_entropy;
111 EXPORT_SYMBOL(latent_entropy);
112 #endif
113 
114 /*
115  * Array of node states.
116  */
117 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
118 	[N_POSSIBLE] = NODE_MASK_ALL,
119 	[N_ONLINE] = { { [0] = 1UL } },
120 #ifndef CONFIG_NUMA
121 	[N_NORMAL_MEMORY] = { { [0] = 1UL } },
122 #ifdef CONFIG_HIGHMEM
123 	[N_HIGH_MEMORY] = { { [0] = 1UL } },
124 #endif
125 	[N_MEMORY] = { { [0] = 1UL } },
126 	[N_CPU] = { { [0] = 1UL } },
127 #endif	/* NUMA */
128 };
129 EXPORT_SYMBOL(node_states);
130 
131 atomic_long_t _totalram_pages __read_mostly;
132 EXPORT_SYMBOL(_totalram_pages);
133 unsigned long totalreserve_pages __read_mostly;
134 unsigned long totalcma_pages __read_mostly;
135 
136 int percpu_pagelist_fraction;
137 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
138 #ifdef CONFIG_INIT_ON_ALLOC_DEFAULT_ON
139 DEFINE_STATIC_KEY_TRUE(init_on_alloc);
140 #else
141 DEFINE_STATIC_KEY_FALSE(init_on_alloc);
142 #endif
143 EXPORT_SYMBOL(init_on_alloc);
144 
145 #ifdef CONFIG_INIT_ON_FREE_DEFAULT_ON
146 DEFINE_STATIC_KEY_TRUE(init_on_free);
147 #else
148 DEFINE_STATIC_KEY_FALSE(init_on_free);
149 #endif
150 EXPORT_SYMBOL(init_on_free);
151 
152 static int __init early_init_on_alloc(char *buf)
153 {
154 	int ret;
155 	bool bool_result;
156 
157 	if (!buf)
158 		return -EINVAL;
159 	ret = kstrtobool(buf, &bool_result);
160 	if (bool_result && page_poisoning_enabled())
161 		pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_alloc\n");
162 	if (bool_result)
163 		static_branch_enable(&init_on_alloc);
164 	else
165 		static_branch_disable(&init_on_alloc);
166 	return ret;
167 }
168 early_param("init_on_alloc", early_init_on_alloc);
169 
170 static int __init early_init_on_free(char *buf)
171 {
172 	int ret;
173 	bool bool_result;
174 
175 	if (!buf)
176 		return -EINVAL;
177 	ret = kstrtobool(buf, &bool_result);
178 	if (bool_result && page_poisoning_enabled())
179 		pr_info("mem auto-init: CONFIG_PAGE_POISONING is on, will take precedence over init_on_free\n");
180 	if (bool_result)
181 		static_branch_enable(&init_on_free);
182 	else
183 		static_branch_disable(&init_on_free);
184 	return ret;
185 }
186 early_param("init_on_free", early_init_on_free);
187 
188 /*
189  * A cached value of the page's pageblock's migratetype, used when the page is
190  * put on a pcplist. Used to avoid the pageblock migratetype lookup when
191  * freeing from pcplists in most cases, at the cost of possibly becoming stale.
192  * Also the migratetype set in the page does not necessarily match the pcplist
193  * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
194  * other index - this ensures that it will be put on the correct CMA freelist.
195  */
196 static inline int get_pcppage_migratetype(struct page *page)
197 {
198 	return page->index;
199 }
200 
201 static inline void set_pcppage_migratetype(struct page *page, int migratetype)
202 {
203 	page->index = migratetype;
204 }
205 
206 #ifdef CONFIG_PM_SLEEP
207 /*
208  * The following functions are used by the suspend/hibernate code to temporarily
209  * change gfp_allowed_mask in order to avoid using I/O during memory allocations
210  * while devices are suspended.  To avoid races with the suspend/hibernate code,
211  * they should always be called with system_transition_mutex held
212  * (gfp_allowed_mask also should only be modified with system_transition_mutex
213  * held, unless the suspend/hibernate code is guaranteed not to run in parallel
214  * with that modification).
215  */
216 
217 static gfp_t saved_gfp_mask;
218 
219 void pm_restore_gfp_mask(void)
220 {
221 	WARN_ON(!mutex_is_locked(&system_transition_mutex));
222 	if (saved_gfp_mask) {
223 		gfp_allowed_mask = saved_gfp_mask;
224 		saved_gfp_mask = 0;
225 	}
226 }
227 
228 void pm_restrict_gfp_mask(void)
229 {
230 	WARN_ON(!mutex_is_locked(&system_transition_mutex));
231 	WARN_ON(saved_gfp_mask);
232 	saved_gfp_mask = gfp_allowed_mask;
233 	gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
234 }
235 
236 bool pm_suspended_storage(void)
237 {
238 	if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS))
239 		return false;
240 	return true;
241 }
242 #endif /* CONFIG_PM_SLEEP */
243 
244 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
245 unsigned int pageblock_order __read_mostly;
246 #endif
247 
248 static void __free_pages_ok(struct page *page, unsigned int order);
249 
250 /*
251  * results with 256, 32 in the lowmem_reserve sysctl:
252  *	1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
253  *	1G machine -> (16M dma, 784M normal, 224M high)
254  *	NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
255  *	HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
256  *	HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA
257  *
258  * TBD: should special case ZONE_DMA32 machines here - in those we normally
259  * don't need any ZONE_NORMAL reservation
260  */
261 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = {
262 #ifdef CONFIG_ZONE_DMA
263 	[ZONE_DMA] = 256,
264 #endif
265 #ifdef CONFIG_ZONE_DMA32
266 	[ZONE_DMA32] = 256,
267 #endif
268 	[ZONE_NORMAL] = 32,
269 #ifdef CONFIG_HIGHMEM
270 	[ZONE_HIGHMEM] = 0,
271 #endif
272 	[ZONE_MOVABLE] = 0,
273 };
274 
275 static char * const zone_names[MAX_NR_ZONES] = {
276 #ifdef CONFIG_ZONE_DMA
277 	 "DMA",
278 #endif
279 #ifdef CONFIG_ZONE_DMA32
280 	 "DMA32",
281 #endif
282 	 "Normal",
283 #ifdef CONFIG_HIGHMEM
284 	 "HighMem",
285 #endif
286 	 "Movable",
287 #ifdef CONFIG_ZONE_DEVICE
288 	 "Device",
289 #endif
290 };
291 
292 const char * const migratetype_names[MIGRATE_TYPES] = {
293 	"Unmovable",
294 	"Movable",
295 	"Reclaimable",
296 	"HighAtomic",
297 #ifdef CONFIG_CMA
298 	"CMA",
299 #endif
300 #ifdef CONFIG_MEMORY_ISOLATION
301 	"Isolate",
302 #endif
303 };
304 
305 compound_page_dtor * const compound_page_dtors[] = {
306 	NULL,
307 	free_compound_page,
308 #ifdef CONFIG_HUGETLB_PAGE
309 	free_huge_page,
310 #endif
311 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
312 	free_transhuge_page,
313 #endif
314 };
315 
316 int min_free_kbytes = 1024;
317 int user_min_free_kbytes = -1;
318 #ifdef CONFIG_DISCONTIGMEM
319 /*
320  * DiscontigMem defines memory ranges as separate pg_data_t even if the ranges
321  * are not on separate NUMA nodes. Functionally this works but with
322  * watermark_boost_factor, it can reclaim prematurely as the ranges can be
323  * quite small. By default, do not boost watermarks on discontigmem as in
324  * many cases very high-order allocations like THP are likely to be
325  * unsupported and the premature reclaim offsets the advantage of long-term
326  * fragmentation avoidance.
327  */
328 int watermark_boost_factor __read_mostly;
329 #else
330 int watermark_boost_factor __read_mostly = 15000;
331 #endif
332 int watermark_scale_factor = 10;
333 
334 static unsigned long nr_kernel_pages __initdata;
335 static unsigned long nr_all_pages __initdata;
336 static unsigned long dma_reserve __initdata;
337 
338 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
339 static unsigned long arch_zone_lowest_possible_pfn[MAX_NR_ZONES] __initdata;
340 static unsigned long arch_zone_highest_possible_pfn[MAX_NR_ZONES] __initdata;
341 static unsigned long required_kernelcore __initdata;
342 static unsigned long required_kernelcore_percent __initdata;
343 static unsigned long required_movablecore __initdata;
344 static unsigned long required_movablecore_percent __initdata;
345 static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
346 static bool mirrored_kernelcore __meminitdata;
347 
348 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
349 int movable_zone;
350 EXPORT_SYMBOL(movable_zone);
351 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
352 
353 #if MAX_NUMNODES > 1
354 unsigned int nr_node_ids __read_mostly = MAX_NUMNODES;
355 unsigned int nr_online_nodes __read_mostly = 1;
356 EXPORT_SYMBOL(nr_node_ids);
357 EXPORT_SYMBOL(nr_online_nodes);
358 #endif
359 
360 int page_group_by_mobility_disabled __read_mostly;
361 
362 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
363 /*
364  * During boot we initialize deferred pages on-demand, as needed, but once
365  * page_alloc_init_late() has finished, the deferred pages are all initialized,
366  * and we can permanently disable that path.
367  */
368 static DEFINE_STATIC_KEY_TRUE(deferred_pages);
369 
370 /*
371  * Calling kasan_free_pages() only after deferred memory initialization
372  * has completed. Poisoning pages during deferred memory init will greatly
373  * lengthen the process and cause problem in large memory systems as the
374  * deferred pages initialization is done with interrupt disabled.
375  *
376  * Assuming that there will be no reference to those newly initialized
377  * pages before they are ever allocated, this should have no effect on
378  * KASAN memory tracking as the poison will be properly inserted at page
379  * allocation time. The only corner case is when pages are allocated by
380  * on-demand allocation and then freed again before the deferred pages
381  * initialization is done, but this is not likely to happen.
382  */
383 static inline void kasan_free_nondeferred_pages(struct page *page, int order)
384 {
385 	if (!static_branch_unlikely(&deferred_pages))
386 		kasan_free_pages(page, order);
387 }
388 
389 /* Returns true if the struct page for the pfn is uninitialised */
390 static inline bool __meminit early_page_uninitialised(unsigned long pfn)
391 {
392 	int nid = early_pfn_to_nid(pfn);
393 
394 	if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn)
395 		return true;
396 
397 	return false;
398 }
399 
400 /*
401  * Returns true when the remaining initialisation should be deferred until
402  * later in the boot cycle when it can be parallelised.
403  */
404 static bool __meminit
405 defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
406 {
407 	static unsigned long prev_end_pfn, nr_initialised;
408 
409 	/*
410 	 * prev_end_pfn static that contains the end of previous zone
411 	 * No need to protect because called very early in boot before smp_init.
412 	 */
413 	if (prev_end_pfn != end_pfn) {
414 		prev_end_pfn = end_pfn;
415 		nr_initialised = 0;
416 	}
417 
418 	/* Always populate low zones for address-constrained allocations */
419 	if (end_pfn < pgdat_end_pfn(NODE_DATA(nid)))
420 		return false;
421 
422 	/*
423 	 * We start only with one section of pages, more pages are added as
424 	 * needed until the rest of deferred pages are initialized.
425 	 */
426 	nr_initialised++;
427 	if ((nr_initialised > PAGES_PER_SECTION) &&
428 	    (pfn & (PAGES_PER_SECTION - 1)) == 0) {
429 		NODE_DATA(nid)->first_deferred_pfn = pfn;
430 		return true;
431 	}
432 	return false;
433 }
434 #else
435 #define kasan_free_nondeferred_pages(p, o)	kasan_free_pages(p, o)
436 
437 static inline bool early_page_uninitialised(unsigned long pfn)
438 {
439 	return false;
440 }
441 
442 static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
443 {
444 	return false;
445 }
446 #endif
447 
448 /* Return a pointer to the bitmap storing bits affecting a block of pages */
449 static inline unsigned long *get_pageblock_bitmap(struct page *page,
450 							unsigned long pfn)
451 {
452 #ifdef CONFIG_SPARSEMEM
453 	return section_to_usemap(__pfn_to_section(pfn));
454 #else
455 	return page_zone(page)->pageblock_flags;
456 #endif /* CONFIG_SPARSEMEM */
457 }
458 
459 static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
460 {
461 #ifdef CONFIG_SPARSEMEM
462 	pfn &= (PAGES_PER_SECTION-1);
463 	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
464 #else
465 	pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
466 	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
467 #endif /* CONFIG_SPARSEMEM */
468 }
469 
470 /**
471  * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
472  * @page: The page within the block of interest
473  * @pfn: The target page frame number
474  * @end_bitidx: The last bit of interest to retrieve
475  * @mask: mask of bits that the caller is interested in
476  *
477  * Return: pageblock_bits flags
478  */
479 static __always_inline unsigned long __get_pfnblock_flags_mask(struct page *page,
480 					unsigned long pfn,
481 					unsigned long end_bitidx,
482 					unsigned long mask)
483 {
484 	unsigned long *bitmap;
485 	unsigned long bitidx, word_bitidx;
486 	unsigned long word;
487 
488 	bitmap = get_pageblock_bitmap(page, pfn);
489 	bitidx = pfn_to_bitidx(page, pfn);
490 	word_bitidx = bitidx / BITS_PER_LONG;
491 	bitidx &= (BITS_PER_LONG-1);
492 
493 	word = bitmap[word_bitidx];
494 	bitidx += end_bitidx;
495 	return (word >> (BITS_PER_LONG - bitidx - 1)) & mask;
496 }
497 
498 unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
499 					unsigned long end_bitidx,
500 					unsigned long mask)
501 {
502 	return __get_pfnblock_flags_mask(page, pfn, end_bitidx, mask);
503 }
504 
505 static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
506 {
507 	return __get_pfnblock_flags_mask(page, pfn, PB_migrate_end, MIGRATETYPE_MASK);
508 }
509 
510 /**
511  * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
512  * @page: The page within the block of interest
513  * @flags: The flags to set
514  * @pfn: The target page frame number
515  * @end_bitidx: The last bit of interest
516  * @mask: mask of bits that the caller is interested in
517  */
518 void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
519 					unsigned long pfn,
520 					unsigned long end_bitidx,
521 					unsigned long mask)
522 {
523 	unsigned long *bitmap;
524 	unsigned long bitidx, word_bitidx;
525 	unsigned long old_word, word;
526 
527 	BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
528 	BUILD_BUG_ON(MIGRATE_TYPES > (1 << PB_migratetype_bits));
529 
530 	bitmap = get_pageblock_bitmap(page, pfn);
531 	bitidx = pfn_to_bitidx(page, pfn);
532 	word_bitidx = bitidx / BITS_PER_LONG;
533 	bitidx &= (BITS_PER_LONG-1);
534 
535 	VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
536 
537 	bitidx += end_bitidx;
538 	mask <<= (BITS_PER_LONG - bitidx - 1);
539 	flags <<= (BITS_PER_LONG - bitidx - 1);
540 
541 	word = READ_ONCE(bitmap[word_bitidx]);
542 	for (;;) {
543 		old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags);
544 		if (word == old_word)
545 			break;
546 		word = old_word;
547 	}
548 }
549 
550 void set_pageblock_migratetype(struct page *page, int migratetype)
551 {
552 	if (unlikely(page_group_by_mobility_disabled &&
553 		     migratetype < MIGRATE_PCPTYPES))
554 		migratetype = MIGRATE_UNMOVABLE;
555 
556 	set_pageblock_flags_group(page, (unsigned long)migratetype,
557 					PB_migrate, PB_migrate_end);
558 }
559 
560 #ifdef CONFIG_DEBUG_VM
561 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
562 {
563 	int ret = 0;
564 	unsigned seq;
565 	unsigned long pfn = page_to_pfn(page);
566 	unsigned long sp, start_pfn;
567 
568 	do {
569 		seq = zone_span_seqbegin(zone);
570 		start_pfn = zone->zone_start_pfn;
571 		sp = zone->spanned_pages;
572 		if (!zone_spans_pfn(zone, pfn))
573 			ret = 1;
574 	} while (zone_span_seqretry(zone, seq));
575 
576 	if (ret)
577 		pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
578 			pfn, zone_to_nid(zone), zone->name,
579 			start_pfn, start_pfn + sp);
580 
581 	return ret;
582 }
583 
584 static int page_is_consistent(struct zone *zone, struct page *page)
585 {
586 	if (!pfn_valid_within(page_to_pfn(page)))
587 		return 0;
588 	if (zone != page_zone(page))
589 		return 0;
590 
591 	return 1;
592 }
593 /*
594  * Temporary debugging check for pages not lying within a given zone.
595  */
596 static int __maybe_unused bad_range(struct zone *zone, struct page *page)
597 {
598 	if (page_outside_zone_boundaries(zone, page))
599 		return 1;
600 	if (!page_is_consistent(zone, page))
601 		return 1;
602 
603 	return 0;
604 }
605 #else
606 static inline int __maybe_unused bad_range(struct zone *zone, struct page *page)
607 {
608 	return 0;
609 }
610 #endif
611 
612 static void bad_page(struct page *page, const char *reason,
613 		unsigned long bad_flags)
614 {
615 	static unsigned long resume;
616 	static unsigned long nr_shown;
617 	static unsigned long nr_unshown;
618 
619 	/*
620 	 * Allow a burst of 60 reports, then keep quiet for that minute;
621 	 * or allow a steady drip of one report per second.
622 	 */
623 	if (nr_shown == 60) {
624 		if (time_before(jiffies, resume)) {
625 			nr_unshown++;
626 			goto out;
627 		}
628 		if (nr_unshown) {
629 			pr_alert(
630 			      "BUG: Bad page state: %lu messages suppressed\n",
631 				nr_unshown);
632 			nr_unshown = 0;
633 		}
634 		nr_shown = 0;
635 	}
636 	if (nr_shown++ == 0)
637 		resume = jiffies + 60 * HZ;
638 
639 	pr_alert("BUG: Bad page state in process %s  pfn:%05lx\n",
640 		current->comm, page_to_pfn(page));
641 	__dump_page(page, reason);
642 	bad_flags &= page->flags;
643 	if (bad_flags)
644 		pr_alert("bad because of flags: %#lx(%pGp)\n",
645 						bad_flags, &bad_flags);
646 	dump_page_owner(page);
647 
648 	print_modules();
649 	dump_stack();
650 out:
651 	/* Leave bad fields for debug, except PageBuddy could make trouble */
652 	page_mapcount_reset(page); /* remove PageBuddy */
653 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
654 }
655 
656 /*
657  * Higher-order pages are called "compound pages".  They are structured thusly:
658  *
659  * The first PAGE_SIZE page is called the "head page" and have PG_head set.
660  *
661  * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded
662  * in bit 0 of page->compound_head. The rest of bits is pointer to head page.
663  *
664  * The first tail page's ->compound_dtor holds the offset in array of compound
665  * page destructors. See compound_page_dtors.
666  *
667  * The first tail page's ->compound_order holds the order of allocation.
668  * This usage means that zero-order pages may not be compound.
669  */
670 
671 void free_compound_page(struct page *page)
672 {
673 	mem_cgroup_uncharge(page);
674 	__free_pages_ok(page, compound_order(page));
675 }
676 
677 void prep_compound_page(struct page *page, unsigned int order)
678 {
679 	int i;
680 	int nr_pages = 1 << order;
681 
682 	set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
683 	set_compound_order(page, order);
684 	__SetPageHead(page);
685 	for (i = 1; i < nr_pages; i++) {
686 		struct page *p = page + i;
687 		set_page_count(p, 0);
688 		p->mapping = TAIL_MAPPING;
689 		set_compound_head(p, page);
690 	}
691 	atomic_set(compound_mapcount_ptr(page), -1);
692 }
693 
694 #ifdef CONFIG_DEBUG_PAGEALLOC
695 unsigned int _debug_guardpage_minorder;
696 
697 #ifdef CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT
698 DEFINE_STATIC_KEY_TRUE(_debug_pagealloc_enabled);
699 #else
700 DEFINE_STATIC_KEY_FALSE(_debug_pagealloc_enabled);
701 #endif
702 EXPORT_SYMBOL(_debug_pagealloc_enabled);
703 
704 DEFINE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
705 
706 static int __init early_debug_pagealloc(char *buf)
707 {
708 	bool enable = false;
709 
710 	if (kstrtobool(buf, &enable))
711 		return -EINVAL;
712 
713 	if (enable)
714 		static_branch_enable(&_debug_pagealloc_enabled);
715 
716 	return 0;
717 }
718 early_param("debug_pagealloc", early_debug_pagealloc);
719 
720 static void init_debug_guardpage(void)
721 {
722 	if (!debug_pagealloc_enabled())
723 		return;
724 
725 	if (!debug_guardpage_minorder())
726 		return;
727 
728 	static_branch_enable(&_debug_guardpage_enabled);
729 }
730 
731 static int __init debug_guardpage_minorder_setup(char *buf)
732 {
733 	unsigned long res;
734 
735 	if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
736 		pr_err("Bad debug_guardpage_minorder value\n");
737 		return 0;
738 	}
739 	_debug_guardpage_minorder = res;
740 	pr_info("Setting debug_guardpage_minorder to %lu\n", res);
741 	return 0;
742 }
743 early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
744 
745 static inline bool set_page_guard(struct zone *zone, struct page *page,
746 				unsigned int order, int migratetype)
747 {
748 	if (!debug_guardpage_enabled())
749 		return false;
750 
751 	if (order >= debug_guardpage_minorder())
752 		return false;
753 
754 	__SetPageGuard(page);
755 	INIT_LIST_HEAD(&page->lru);
756 	set_page_private(page, order);
757 	/* Guard pages are not available for any usage */
758 	__mod_zone_freepage_state(zone, -(1 << order), migratetype);
759 
760 	return true;
761 }
762 
763 static inline void clear_page_guard(struct zone *zone, struct page *page,
764 				unsigned int order, int migratetype)
765 {
766 	if (!debug_guardpage_enabled())
767 		return;
768 
769 	__ClearPageGuard(page);
770 
771 	set_page_private(page, 0);
772 	if (!is_migrate_isolate(migratetype))
773 		__mod_zone_freepage_state(zone, (1 << order), migratetype);
774 }
775 #else
776 static inline bool set_page_guard(struct zone *zone, struct page *page,
777 			unsigned int order, int migratetype) { return false; }
778 static inline void clear_page_guard(struct zone *zone, struct page *page,
779 				unsigned int order, int migratetype) {}
780 #endif
781 
782 static inline void set_page_order(struct page *page, unsigned int order)
783 {
784 	set_page_private(page, order);
785 	__SetPageBuddy(page);
786 }
787 
788 /*
789  * This function checks whether a page is free && is the buddy
790  * we can coalesce a page and its buddy if
791  * (a) the buddy is not in a hole (check before calling!) &&
792  * (b) the buddy is in the buddy system &&
793  * (c) a page and its buddy have the same order &&
794  * (d) a page and its buddy are in the same zone.
795  *
796  * For recording whether a page is in the buddy system, we set PageBuddy.
797  * Setting, clearing, and testing PageBuddy is serialized by zone->lock.
798  *
799  * For recording page's order, we use page_private(page).
800  */
801 static inline int page_is_buddy(struct page *page, struct page *buddy,
802 							unsigned int order)
803 {
804 	if (page_is_guard(buddy) && page_order(buddy) == order) {
805 		if (page_zone_id(page) != page_zone_id(buddy))
806 			return 0;
807 
808 		VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
809 
810 		return 1;
811 	}
812 
813 	if (PageBuddy(buddy) && page_order(buddy) == order) {
814 		/*
815 		 * zone check is done late to avoid uselessly
816 		 * calculating zone/node ids for pages that could
817 		 * never merge.
818 		 */
819 		if (page_zone_id(page) != page_zone_id(buddy))
820 			return 0;
821 
822 		VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
823 
824 		return 1;
825 	}
826 	return 0;
827 }
828 
829 #ifdef CONFIG_COMPACTION
830 static inline struct capture_control *task_capc(struct zone *zone)
831 {
832 	struct capture_control *capc = current->capture_control;
833 
834 	return capc &&
835 		!(current->flags & PF_KTHREAD) &&
836 		!capc->page &&
837 		capc->cc->zone == zone &&
838 		capc->cc->direct_compaction ? capc : NULL;
839 }
840 
841 static inline bool
842 compaction_capture(struct capture_control *capc, struct page *page,
843 		   int order, int migratetype)
844 {
845 	if (!capc || order != capc->cc->order)
846 		return false;
847 
848 	/* Do not accidentally pollute CMA or isolated regions*/
849 	if (is_migrate_cma(migratetype) ||
850 	    is_migrate_isolate(migratetype))
851 		return false;
852 
853 	/*
854 	 * Do not let lower order allocations polluate a movable pageblock.
855 	 * This might let an unmovable request use a reclaimable pageblock
856 	 * and vice-versa but no more than normal fallback logic which can
857 	 * have trouble finding a high-order free page.
858 	 */
859 	if (order < pageblock_order && migratetype == MIGRATE_MOVABLE)
860 		return false;
861 
862 	capc->page = page;
863 	return true;
864 }
865 
866 #else
867 static inline struct capture_control *task_capc(struct zone *zone)
868 {
869 	return NULL;
870 }
871 
872 static inline bool
873 compaction_capture(struct capture_control *capc, struct page *page,
874 		   int order, int migratetype)
875 {
876 	return false;
877 }
878 #endif /* CONFIG_COMPACTION */
879 
880 /*
881  * Freeing function for a buddy system allocator.
882  *
883  * The concept of a buddy system is to maintain direct-mapped table
884  * (containing bit values) for memory blocks of various "orders".
885  * The bottom level table contains the map for the smallest allocatable
886  * units of memory (here, pages), and each level above it describes
887  * pairs of units from the levels below, hence, "buddies".
888  * At a high level, all that happens here is marking the table entry
889  * at the bottom level available, and propagating the changes upward
890  * as necessary, plus some accounting needed to play nicely with other
891  * parts of the VM system.
892  * At each level, we keep a list of pages, which are heads of continuous
893  * free pages of length of (1 << order) and marked with PageBuddy.
894  * Page's order is recorded in page_private(page) field.
895  * So when we are allocating or freeing one, we can derive the state of the
896  * other.  That is, if we allocate a small block, and both were
897  * free, the remainder of the region must be split into blocks.
898  * If a block is freed, and its buddy is also free, then this
899  * triggers coalescing into a block of larger size.
900  *
901  * -- nyc
902  */
903 
904 static inline void __free_one_page(struct page *page,
905 		unsigned long pfn,
906 		struct zone *zone, unsigned int order,
907 		int migratetype)
908 {
909 	unsigned long combined_pfn;
910 	unsigned long uninitialized_var(buddy_pfn);
911 	struct page *buddy;
912 	unsigned int max_order;
913 	struct capture_control *capc = task_capc(zone);
914 
915 	max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);
916 
917 	VM_BUG_ON(!zone_is_initialized(zone));
918 	VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
919 
920 	VM_BUG_ON(migratetype == -1);
921 	if (likely(!is_migrate_isolate(migratetype)))
922 		__mod_zone_freepage_state(zone, 1 << order, migratetype);
923 
924 	VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
925 	VM_BUG_ON_PAGE(bad_range(zone, page), page);
926 
927 continue_merging:
928 	while (order < max_order - 1) {
929 		if (compaction_capture(capc, page, order, migratetype)) {
930 			__mod_zone_freepage_state(zone, -(1 << order),
931 								migratetype);
932 			return;
933 		}
934 		buddy_pfn = __find_buddy_pfn(pfn, order);
935 		buddy = page + (buddy_pfn - pfn);
936 
937 		if (!pfn_valid_within(buddy_pfn))
938 			goto done_merging;
939 		if (!page_is_buddy(page, buddy, order))
940 			goto done_merging;
941 		/*
942 		 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
943 		 * merge with it and move up one order.
944 		 */
945 		if (page_is_guard(buddy))
946 			clear_page_guard(zone, buddy, order, migratetype);
947 		else
948 			del_page_from_free_area(buddy, &zone->free_area[order]);
949 		combined_pfn = buddy_pfn & pfn;
950 		page = page + (combined_pfn - pfn);
951 		pfn = combined_pfn;
952 		order++;
953 	}
954 	if (max_order < MAX_ORDER) {
955 		/* If we are here, it means order is >= pageblock_order.
956 		 * We want to prevent merge between freepages on isolate
957 		 * pageblock and normal pageblock. Without this, pageblock
958 		 * isolation could cause incorrect freepage or CMA accounting.
959 		 *
960 		 * We don't want to hit this code for the more frequent
961 		 * low-order merging.
962 		 */
963 		if (unlikely(has_isolate_pageblock(zone))) {
964 			int buddy_mt;
965 
966 			buddy_pfn = __find_buddy_pfn(pfn, order);
967 			buddy = page + (buddy_pfn - pfn);
968 			buddy_mt = get_pageblock_migratetype(buddy);
969 
970 			if (migratetype != buddy_mt
971 					&& (is_migrate_isolate(migratetype) ||
972 						is_migrate_isolate(buddy_mt)))
973 				goto done_merging;
974 		}
975 		max_order++;
976 		goto continue_merging;
977 	}
978 
979 done_merging:
980 	set_page_order(page, order);
981 
982 	/*
983 	 * If this is not the largest possible page, check if the buddy
984 	 * of the next-highest order is free. If it is, it's possible
985 	 * that pages are being freed that will coalesce soon. In case,
986 	 * that is happening, add the free page to the tail of the list
987 	 * so it's less likely to be used soon and more likely to be merged
988 	 * as a higher order page
989 	 */
990 	if ((order < MAX_ORDER-2) && pfn_valid_within(buddy_pfn)
991 			&& !is_shuffle_order(order)) {
992 		struct page *higher_page, *higher_buddy;
993 		combined_pfn = buddy_pfn & pfn;
994 		higher_page = page + (combined_pfn - pfn);
995 		buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1);
996 		higher_buddy = higher_page + (buddy_pfn - combined_pfn);
997 		if (pfn_valid_within(buddy_pfn) &&
998 		    page_is_buddy(higher_page, higher_buddy, order + 1)) {
999 			add_to_free_area_tail(page, &zone->free_area[order],
1000 					      migratetype);
1001 			return;
1002 		}
1003 	}
1004 
1005 	if (is_shuffle_order(order))
1006 		add_to_free_area_random(page, &zone->free_area[order],
1007 				migratetype);
1008 	else
1009 		add_to_free_area(page, &zone->free_area[order], migratetype);
1010 
1011 }
1012 
1013 /*
1014  * A bad page could be due to a number of fields. Instead of multiple branches,
1015  * try and check multiple fields with one check. The caller must do a detailed
1016  * check if necessary.
1017  */
1018 static inline bool page_expected_state(struct page *page,
1019 					unsigned long check_flags)
1020 {
1021 	if (unlikely(atomic_read(&page->_mapcount) != -1))
1022 		return false;
1023 
1024 	if (unlikely((unsigned long)page->mapping |
1025 			page_ref_count(page) |
1026 #ifdef CONFIG_MEMCG
1027 			(unsigned long)page->mem_cgroup |
1028 #endif
1029 			(page->flags & check_flags)))
1030 		return false;
1031 
1032 	return true;
1033 }
1034 
1035 static void free_pages_check_bad(struct page *page)
1036 {
1037 	const char *bad_reason;
1038 	unsigned long bad_flags;
1039 
1040 	bad_reason = NULL;
1041 	bad_flags = 0;
1042 
1043 	if (unlikely(atomic_read(&page->_mapcount) != -1))
1044 		bad_reason = "nonzero mapcount";
1045 	if (unlikely(page->mapping != NULL))
1046 		bad_reason = "non-NULL mapping";
1047 	if (unlikely(page_ref_count(page) != 0))
1048 		bad_reason = "nonzero _refcount";
1049 	if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
1050 		bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
1051 		bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
1052 	}
1053 #ifdef CONFIG_MEMCG
1054 	if (unlikely(page->mem_cgroup))
1055 		bad_reason = "page still charged to cgroup";
1056 #endif
1057 	bad_page(page, bad_reason, bad_flags);
1058 }
1059 
1060 static inline int free_pages_check(struct page *page)
1061 {
1062 	if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE)))
1063 		return 0;
1064 
1065 	/* Something has gone sideways, find it */
1066 	free_pages_check_bad(page);
1067 	return 1;
1068 }
1069 
1070 static int free_tail_pages_check(struct page *head_page, struct page *page)
1071 {
1072 	int ret = 1;
1073 
1074 	/*
1075 	 * We rely page->lru.next never has bit 0 set, unless the page
1076 	 * is PageTail(). Let's make sure that's true even for poisoned ->lru.
1077 	 */
1078 	BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1);
1079 
1080 	if (!IS_ENABLED(CONFIG_DEBUG_VM)) {
1081 		ret = 0;
1082 		goto out;
1083 	}
1084 	switch (page - head_page) {
1085 	case 1:
1086 		/* the first tail page: ->mapping may be compound_mapcount() */
1087 		if (unlikely(compound_mapcount(page))) {
1088 			bad_page(page, "nonzero compound_mapcount", 0);
1089 			goto out;
1090 		}
1091 		break;
1092 	case 2:
1093 		/*
1094 		 * the second tail page: ->mapping is
1095 		 * deferred_list.next -- ignore value.
1096 		 */
1097 		break;
1098 	default:
1099 		if (page->mapping != TAIL_MAPPING) {
1100 			bad_page(page, "corrupted mapping in tail page", 0);
1101 			goto out;
1102 		}
1103 		break;
1104 	}
1105 	if (unlikely(!PageTail(page))) {
1106 		bad_page(page, "PageTail not set", 0);
1107 		goto out;
1108 	}
1109 	if (unlikely(compound_head(page) != head_page)) {
1110 		bad_page(page, "compound_head not consistent", 0);
1111 		goto out;
1112 	}
1113 	ret = 0;
1114 out:
1115 	page->mapping = NULL;
1116 	clear_compound_head(page);
1117 	return ret;
1118 }
1119 
1120 static void kernel_init_free_pages(struct page *page, int numpages)
1121 {
1122 	int i;
1123 
1124 	for (i = 0; i < numpages; i++)
1125 		clear_highpage(page + i);
1126 }
1127 
1128 static __always_inline bool free_pages_prepare(struct page *page,
1129 					unsigned int order, bool check_free)
1130 {
1131 	int bad = 0;
1132 
1133 	VM_BUG_ON_PAGE(PageTail(page), page);
1134 
1135 	trace_mm_page_free(page, order);
1136 
1137 	/*
1138 	 * Check tail pages before head page information is cleared to
1139 	 * avoid checking PageCompound for order-0 pages.
1140 	 */
1141 	if (unlikely(order)) {
1142 		bool compound = PageCompound(page);
1143 		int i;
1144 
1145 		VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
1146 
1147 		if (compound)
1148 			ClearPageDoubleMap(page);
1149 		for (i = 1; i < (1 << order); i++) {
1150 			if (compound)
1151 				bad += free_tail_pages_check(page, page + i);
1152 			if (unlikely(free_pages_check(page + i))) {
1153 				bad++;
1154 				continue;
1155 			}
1156 			(page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1157 		}
1158 	}
1159 	if (PageMappingFlags(page))
1160 		page->mapping = NULL;
1161 	if (memcg_kmem_enabled() && PageKmemcg(page))
1162 		__memcg_kmem_uncharge(page, order);
1163 	if (check_free)
1164 		bad += free_pages_check(page);
1165 	if (bad)
1166 		return false;
1167 
1168 	page_cpupid_reset_last(page);
1169 	page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1170 	reset_page_owner(page, order);
1171 
1172 	if (!PageHighMem(page)) {
1173 		debug_check_no_locks_freed(page_address(page),
1174 					   PAGE_SIZE << order);
1175 		debug_check_no_obj_freed(page_address(page),
1176 					   PAGE_SIZE << order);
1177 	}
1178 	arch_free_page(page, order);
1179 	if (want_init_on_free())
1180 		kernel_init_free_pages(page, 1 << order);
1181 
1182 	kernel_poison_pages(page, 1 << order, 0);
1183 	if (debug_pagealloc_enabled())
1184 		kernel_map_pages(page, 1 << order, 0);
1185 
1186 	kasan_free_nondeferred_pages(page, order);
1187 
1188 	return true;
1189 }
1190 
1191 #ifdef CONFIG_DEBUG_VM
1192 /*
1193  * With DEBUG_VM enabled, order-0 pages are checked immediately when being freed
1194  * to pcp lists. With debug_pagealloc also enabled, they are also rechecked when
1195  * moved from pcp lists to free lists.
1196  */
1197 static bool free_pcp_prepare(struct page *page)
1198 {
1199 	return free_pages_prepare(page, 0, true);
1200 }
1201 
1202 static bool bulkfree_pcp_prepare(struct page *page)
1203 {
1204 	if (debug_pagealloc_enabled())
1205 		return free_pages_check(page);
1206 	else
1207 		return false;
1208 }
1209 #else
1210 /*
1211  * With DEBUG_VM disabled, order-0 pages being freed are checked only when
1212  * moving from pcp lists to free list in order to reduce overhead. With
1213  * debug_pagealloc enabled, they are checked also immediately when being freed
1214  * to the pcp lists.
1215  */
1216 static bool free_pcp_prepare(struct page *page)
1217 {
1218 	if (debug_pagealloc_enabled())
1219 		return free_pages_prepare(page, 0, true);
1220 	else
1221 		return free_pages_prepare(page, 0, false);
1222 }
1223 
1224 static bool bulkfree_pcp_prepare(struct page *page)
1225 {
1226 	return free_pages_check(page);
1227 }
1228 #endif /* CONFIG_DEBUG_VM */
1229 
1230 static inline void prefetch_buddy(struct page *page)
1231 {
1232 	unsigned long pfn = page_to_pfn(page);
1233 	unsigned long buddy_pfn = __find_buddy_pfn(pfn, 0);
1234 	struct page *buddy = page + (buddy_pfn - pfn);
1235 
1236 	prefetch(buddy);
1237 }
1238 
1239 /*
1240  * Frees a number of pages from the PCP lists
1241  * Assumes all pages on list are in same zone, and of same order.
1242  * count is the number of pages to free.
1243  *
1244  * If the zone was previously in an "all pages pinned" state then look to
1245  * see if this freeing clears that state.
1246  *
1247  * And clear the zone's pages_scanned counter, to hold off the "all pages are
1248  * pinned" detection logic.
1249  */
1250 static void free_pcppages_bulk(struct zone *zone, int count,
1251 					struct per_cpu_pages *pcp)
1252 {
1253 	int migratetype = 0;
1254 	int batch_free = 0;
1255 	int prefetch_nr = 0;
1256 	bool isolated_pageblocks;
1257 	struct page *page, *tmp;
1258 	LIST_HEAD(head);
1259 
1260 	while (count) {
1261 		struct list_head *list;
1262 
1263 		/*
1264 		 * Remove pages from lists in a round-robin fashion. A
1265 		 * batch_free count is maintained that is incremented when an
1266 		 * empty list is encountered.  This is so more pages are freed
1267 		 * off fuller lists instead of spinning excessively around empty
1268 		 * lists
1269 		 */
1270 		do {
1271 			batch_free++;
1272 			if (++migratetype == MIGRATE_PCPTYPES)
1273 				migratetype = 0;
1274 			list = &pcp->lists[migratetype];
1275 		} while (list_empty(list));
1276 
1277 		/* This is the only non-empty list. Free them all. */
1278 		if (batch_free == MIGRATE_PCPTYPES)
1279 			batch_free = count;
1280 
1281 		do {
1282 			page = list_last_entry(list, struct page, lru);
1283 			/* must delete to avoid corrupting pcp list */
1284 			list_del(&page->lru);
1285 			pcp->count--;
1286 
1287 			if (bulkfree_pcp_prepare(page))
1288 				continue;
1289 
1290 			list_add_tail(&page->lru, &head);
1291 
1292 			/*
1293 			 * We are going to put the page back to the global
1294 			 * pool, prefetch its buddy to speed up later access
1295 			 * under zone->lock. It is believed the overhead of
1296 			 * an additional test and calculating buddy_pfn here
1297 			 * can be offset by reduced memory latency later. To
1298 			 * avoid excessive prefetching due to large count, only
1299 			 * prefetch buddy for the first pcp->batch nr of pages.
1300 			 */
1301 			if (prefetch_nr++ < pcp->batch)
1302 				prefetch_buddy(page);
1303 		} while (--count && --batch_free && !list_empty(list));
1304 	}
1305 
1306 	spin_lock(&zone->lock);
1307 	isolated_pageblocks = has_isolate_pageblock(zone);
1308 
1309 	/*
1310 	 * Use safe version since after __free_one_page(),
1311 	 * page->lru.next will not point to original list.
1312 	 */
1313 	list_for_each_entry_safe(page, tmp, &head, lru) {
1314 		int mt = get_pcppage_migratetype(page);
1315 		/* MIGRATE_ISOLATE page should not go to pcplists */
1316 		VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
1317 		/* Pageblock could have been isolated meanwhile */
1318 		if (unlikely(isolated_pageblocks))
1319 			mt = get_pageblock_migratetype(page);
1320 
1321 		__free_one_page(page, page_to_pfn(page), zone, 0, mt);
1322 		trace_mm_page_pcpu_drain(page, 0, mt);
1323 	}
1324 	spin_unlock(&zone->lock);
1325 }
1326 
1327 static void free_one_page(struct zone *zone,
1328 				struct page *page, unsigned long pfn,
1329 				unsigned int order,
1330 				int migratetype)
1331 {
1332 	spin_lock(&zone->lock);
1333 	if (unlikely(has_isolate_pageblock(zone) ||
1334 		is_migrate_isolate(migratetype))) {
1335 		migratetype = get_pfnblock_migratetype(page, pfn);
1336 	}
1337 	__free_one_page(page, pfn, zone, order, migratetype);
1338 	spin_unlock(&zone->lock);
1339 }
1340 
1341 static void __meminit __init_single_page(struct page *page, unsigned long pfn,
1342 				unsigned long zone, int nid)
1343 {
1344 	mm_zero_struct_page(page);
1345 	set_page_links(page, zone, nid, pfn);
1346 	init_page_count(page);
1347 	page_mapcount_reset(page);
1348 	page_cpupid_reset_last(page);
1349 	page_kasan_tag_reset(page);
1350 
1351 	INIT_LIST_HEAD(&page->lru);
1352 #ifdef WANT_PAGE_VIRTUAL
1353 	/* The shift won't overflow because ZONE_NORMAL is below 4G. */
1354 	if (!is_highmem_idx(zone))
1355 		set_page_address(page, __va(pfn << PAGE_SHIFT));
1356 #endif
1357 }
1358 
1359 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1360 static void __meminit init_reserved_page(unsigned long pfn)
1361 {
1362 	pg_data_t *pgdat;
1363 	int nid, zid;
1364 
1365 	if (!early_page_uninitialised(pfn))
1366 		return;
1367 
1368 	nid = early_pfn_to_nid(pfn);
1369 	pgdat = NODE_DATA(nid);
1370 
1371 	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1372 		struct zone *zone = &pgdat->node_zones[zid];
1373 
1374 		if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
1375 			break;
1376 	}
1377 	__init_single_page(pfn_to_page(pfn), pfn, zid, nid);
1378 }
1379 #else
1380 static inline void init_reserved_page(unsigned long pfn)
1381 {
1382 }
1383 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1384 
1385 /*
1386  * Initialised pages do not have PageReserved set. This function is
1387  * called for each range allocated by the bootmem allocator and
1388  * marks the pages PageReserved. The remaining valid pages are later
1389  * sent to the buddy page allocator.
1390  */
1391 void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
1392 {
1393 	unsigned long start_pfn = PFN_DOWN(start);
1394 	unsigned long end_pfn = PFN_UP(end);
1395 
1396 	for (; start_pfn < end_pfn; start_pfn++) {
1397 		if (pfn_valid(start_pfn)) {
1398 			struct page *page = pfn_to_page(start_pfn);
1399 
1400 			init_reserved_page(start_pfn);
1401 
1402 			/* Avoid false-positive PageTail() */
1403 			INIT_LIST_HEAD(&page->lru);
1404 
1405 			/*
1406 			 * no need for atomic set_bit because the struct
1407 			 * page is not visible yet so nobody should
1408 			 * access it yet.
1409 			 */
1410 			__SetPageReserved(page);
1411 		}
1412 	}
1413 }
1414 
1415 static void __free_pages_ok(struct page *page, unsigned int order)
1416 {
1417 	unsigned long flags;
1418 	int migratetype;
1419 	unsigned long pfn = page_to_pfn(page);
1420 
1421 	if (!free_pages_prepare(page, order, true))
1422 		return;
1423 
1424 	migratetype = get_pfnblock_migratetype(page, pfn);
1425 	local_irq_save(flags);
1426 	__count_vm_events(PGFREE, 1 << order);
1427 	free_one_page(page_zone(page), page, pfn, order, migratetype);
1428 	local_irq_restore(flags);
1429 }
1430 
1431 void __free_pages_core(struct page *page, unsigned int order)
1432 {
1433 	unsigned int nr_pages = 1 << order;
1434 	struct page *p = page;
1435 	unsigned int loop;
1436 
1437 	prefetchw(p);
1438 	for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
1439 		prefetchw(p + 1);
1440 		__ClearPageReserved(p);
1441 		set_page_count(p, 0);
1442 	}
1443 	__ClearPageReserved(p);
1444 	set_page_count(p, 0);
1445 
1446 	atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
1447 	set_page_refcounted(page);
1448 	__free_pages(page, order);
1449 }
1450 
1451 #if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \
1452 	defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
1453 
1454 static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
1455 
1456 int __meminit early_pfn_to_nid(unsigned long pfn)
1457 {
1458 	static DEFINE_SPINLOCK(early_pfn_lock);
1459 	int nid;
1460 
1461 	spin_lock(&early_pfn_lock);
1462 	nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
1463 	if (nid < 0)
1464 		nid = first_online_node;
1465 	spin_unlock(&early_pfn_lock);
1466 
1467 	return nid;
1468 }
1469 #endif
1470 
1471 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
1472 /* Only safe to use early in boot when initialisation is single-threaded */
1473 static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
1474 {
1475 	int nid;
1476 
1477 	nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
1478 	if (nid >= 0 && nid != node)
1479 		return false;
1480 	return true;
1481 }
1482 
1483 #else
1484 static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
1485 {
1486 	return true;
1487 }
1488 #endif
1489 
1490 
1491 void __init memblock_free_pages(struct page *page, unsigned long pfn,
1492 							unsigned int order)
1493 {
1494 	if (early_page_uninitialised(pfn))
1495 		return;
1496 	__free_pages_core(page, order);
1497 }
1498 
1499 /*
1500  * Check that the whole (or subset of) a pageblock given by the interval of
1501  * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
1502  * with the migration of free compaction scanner. The scanners then need to
1503  * use only pfn_valid_within() check for arches that allow holes within
1504  * pageblocks.
1505  *
1506  * Return struct page pointer of start_pfn, or NULL if checks were not passed.
1507  *
1508  * It's possible on some configurations to have a setup like node0 node1 node0
1509  * i.e. it's possible that all pages within a zones range of pages do not
1510  * belong to a single zone. We assume that a border between node0 and node1
1511  * can occur within a single pageblock, but not a node0 node1 node0
1512  * interleaving within a single pageblock. It is therefore sufficient to check
1513  * the first and last page of a pageblock and avoid checking each individual
1514  * page in a pageblock.
1515  */
1516 struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
1517 				     unsigned long end_pfn, struct zone *zone)
1518 {
1519 	struct page *start_page;
1520 	struct page *end_page;
1521 
1522 	/* end_pfn is one past the range we are checking */
1523 	end_pfn--;
1524 
1525 	if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
1526 		return NULL;
1527 
1528 	start_page = pfn_to_online_page(start_pfn);
1529 	if (!start_page)
1530 		return NULL;
1531 
1532 	if (page_zone(start_page) != zone)
1533 		return NULL;
1534 
1535 	end_page = pfn_to_page(end_pfn);
1536 
1537 	/* This gives a shorter code than deriving page_zone(end_page) */
1538 	if (page_zone_id(start_page) != page_zone_id(end_page))
1539 		return NULL;
1540 
1541 	return start_page;
1542 }
1543 
1544 void set_zone_contiguous(struct zone *zone)
1545 {
1546 	unsigned long block_start_pfn = zone->zone_start_pfn;
1547 	unsigned long block_end_pfn;
1548 
1549 	block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages);
1550 	for (; block_start_pfn < zone_end_pfn(zone);
1551 			block_start_pfn = block_end_pfn,
1552 			 block_end_pfn += pageblock_nr_pages) {
1553 
1554 		block_end_pfn = min(block_end_pfn, zone_end_pfn(zone));
1555 
1556 		if (!__pageblock_pfn_to_page(block_start_pfn,
1557 					     block_end_pfn, zone))
1558 			return;
1559 	}
1560 
1561 	/* We confirm that there is no hole */
1562 	zone->contiguous = true;
1563 }
1564 
1565 void clear_zone_contiguous(struct zone *zone)
1566 {
1567 	zone->contiguous = false;
1568 }
1569 
1570 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1571 static void __init deferred_free_range(unsigned long pfn,
1572 				       unsigned long nr_pages)
1573 {
1574 	struct page *page;
1575 	unsigned long i;
1576 
1577 	if (!nr_pages)
1578 		return;
1579 
1580 	page = pfn_to_page(pfn);
1581 
1582 	/* Free a large naturally-aligned chunk if possible */
1583 	if (nr_pages == pageblock_nr_pages &&
1584 	    (pfn & (pageblock_nr_pages - 1)) == 0) {
1585 		set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1586 		__free_pages_core(page, pageblock_order);
1587 		return;
1588 	}
1589 
1590 	for (i = 0; i < nr_pages; i++, page++, pfn++) {
1591 		if ((pfn & (pageblock_nr_pages - 1)) == 0)
1592 			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1593 		__free_pages_core(page, 0);
1594 	}
1595 }
1596 
1597 /* Completion tracking for deferred_init_memmap() threads */
1598 static atomic_t pgdat_init_n_undone __initdata;
1599 static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp);
1600 
1601 static inline void __init pgdat_init_report_one_done(void)
1602 {
1603 	if (atomic_dec_and_test(&pgdat_init_n_undone))
1604 		complete(&pgdat_init_all_done_comp);
1605 }
1606 
1607 /*
1608  * Returns true if page needs to be initialized or freed to buddy allocator.
1609  *
1610  * First we check if pfn is valid on architectures where it is possible to have
1611  * holes within pageblock_nr_pages. On systems where it is not possible, this
1612  * function is optimized out.
1613  *
1614  * Then, we check if a current large page is valid by only checking the validity
1615  * of the head pfn.
1616  */
1617 static inline bool __init deferred_pfn_valid(unsigned long pfn)
1618 {
1619 	if (!pfn_valid_within(pfn))
1620 		return false;
1621 	if (!(pfn & (pageblock_nr_pages - 1)) && !pfn_valid(pfn))
1622 		return false;
1623 	return true;
1624 }
1625 
1626 /*
1627  * Free pages to buddy allocator. Try to free aligned pages in
1628  * pageblock_nr_pages sizes.
1629  */
1630 static void __init deferred_free_pages(unsigned long pfn,
1631 				       unsigned long end_pfn)
1632 {
1633 	unsigned long nr_pgmask = pageblock_nr_pages - 1;
1634 	unsigned long nr_free = 0;
1635 
1636 	for (; pfn < end_pfn; pfn++) {
1637 		if (!deferred_pfn_valid(pfn)) {
1638 			deferred_free_range(pfn - nr_free, nr_free);
1639 			nr_free = 0;
1640 		} else if (!(pfn & nr_pgmask)) {
1641 			deferred_free_range(pfn - nr_free, nr_free);
1642 			nr_free = 1;
1643 			touch_nmi_watchdog();
1644 		} else {
1645 			nr_free++;
1646 		}
1647 	}
1648 	/* Free the last block of pages to allocator */
1649 	deferred_free_range(pfn - nr_free, nr_free);
1650 }
1651 
1652 /*
1653  * Initialize struct pages.  We minimize pfn page lookups and scheduler checks
1654  * by performing it only once every pageblock_nr_pages.
1655  * Return number of pages initialized.
1656  */
1657 static unsigned long  __init deferred_init_pages(struct zone *zone,
1658 						 unsigned long pfn,
1659 						 unsigned long end_pfn)
1660 {
1661 	unsigned long nr_pgmask = pageblock_nr_pages - 1;
1662 	int nid = zone_to_nid(zone);
1663 	unsigned long nr_pages = 0;
1664 	int zid = zone_idx(zone);
1665 	struct page *page = NULL;
1666 
1667 	for (; pfn < end_pfn; pfn++) {
1668 		if (!deferred_pfn_valid(pfn)) {
1669 			page = NULL;
1670 			continue;
1671 		} else if (!page || !(pfn & nr_pgmask)) {
1672 			page = pfn_to_page(pfn);
1673 			touch_nmi_watchdog();
1674 		} else {
1675 			page++;
1676 		}
1677 		__init_single_page(page, pfn, zid, nid);
1678 		nr_pages++;
1679 	}
1680 	return (nr_pages);
1681 }
1682 
1683 /*
1684  * This function is meant to pre-load the iterator for the zone init.
1685  * Specifically it walks through the ranges until we are caught up to the
1686  * first_init_pfn value and exits there. If we never encounter the value we
1687  * return false indicating there are no valid ranges left.
1688  */
1689 static bool __init
1690 deferred_init_mem_pfn_range_in_zone(u64 *i, struct zone *zone,
1691 				    unsigned long *spfn, unsigned long *epfn,
1692 				    unsigned long first_init_pfn)
1693 {
1694 	u64 j;
1695 
1696 	/*
1697 	 * Start out by walking through the ranges in this zone that have
1698 	 * already been initialized. We don't need to do anything with them
1699 	 * so we just need to flush them out of the system.
1700 	 */
1701 	for_each_free_mem_pfn_range_in_zone(j, zone, spfn, epfn) {
1702 		if (*epfn <= first_init_pfn)
1703 			continue;
1704 		if (*spfn < first_init_pfn)
1705 			*spfn = first_init_pfn;
1706 		*i = j;
1707 		return true;
1708 	}
1709 
1710 	return false;
1711 }
1712 
1713 /*
1714  * Initialize and free pages. We do it in two loops: first we initialize
1715  * struct page, then free to buddy allocator, because while we are
1716  * freeing pages we can access pages that are ahead (computing buddy
1717  * page in __free_one_page()).
1718  *
1719  * In order to try and keep some memory in the cache we have the loop
1720  * broken along max page order boundaries. This way we will not cause
1721  * any issues with the buddy page computation.
1722  */
1723 static unsigned long __init
1724 deferred_init_maxorder(u64 *i, struct zone *zone, unsigned long *start_pfn,
1725 		       unsigned long *end_pfn)
1726 {
1727 	unsigned long mo_pfn = ALIGN(*start_pfn + 1, MAX_ORDER_NR_PAGES);
1728 	unsigned long spfn = *start_pfn, epfn = *end_pfn;
1729 	unsigned long nr_pages = 0;
1730 	u64 j = *i;
1731 
1732 	/* First we loop through and initialize the page values */
1733 	for_each_free_mem_pfn_range_in_zone_from(j, zone, start_pfn, end_pfn) {
1734 		unsigned long t;
1735 
1736 		if (mo_pfn <= *start_pfn)
1737 			break;
1738 
1739 		t = min(mo_pfn, *end_pfn);
1740 		nr_pages += deferred_init_pages(zone, *start_pfn, t);
1741 
1742 		if (mo_pfn < *end_pfn) {
1743 			*start_pfn = mo_pfn;
1744 			break;
1745 		}
1746 	}
1747 
1748 	/* Reset values and now loop through freeing pages as needed */
1749 	swap(j, *i);
1750 
1751 	for_each_free_mem_pfn_range_in_zone_from(j, zone, &spfn, &epfn) {
1752 		unsigned long t;
1753 
1754 		if (mo_pfn <= spfn)
1755 			break;
1756 
1757 		t = min(mo_pfn, epfn);
1758 		deferred_free_pages(spfn, t);
1759 
1760 		if (mo_pfn <= epfn)
1761 			break;
1762 	}
1763 
1764 	return nr_pages;
1765 }
1766 
1767 /* Initialise remaining memory on a node */
1768 static int __init deferred_init_memmap(void *data)
1769 {
1770 	pg_data_t *pgdat = data;
1771 	const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
1772 	unsigned long spfn = 0, epfn = 0, nr_pages = 0;
1773 	unsigned long first_init_pfn, flags;
1774 	unsigned long start = jiffies;
1775 	struct zone *zone;
1776 	int zid;
1777 	u64 i;
1778 
1779 	/* Bind memory initialisation thread to a local node if possible */
1780 	if (!cpumask_empty(cpumask))
1781 		set_cpus_allowed_ptr(current, cpumask);
1782 
1783 	pgdat_resize_lock(pgdat, &flags);
1784 	first_init_pfn = pgdat->first_deferred_pfn;
1785 	if (first_init_pfn == ULONG_MAX) {
1786 		pgdat_resize_unlock(pgdat, &flags);
1787 		pgdat_init_report_one_done();
1788 		return 0;
1789 	}
1790 
1791 	/* Sanity check boundaries */
1792 	BUG_ON(pgdat->first_deferred_pfn < pgdat->node_start_pfn);
1793 	BUG_ON(pgdat->first_deferred_pfn > pgdat_end_pfn(pgdat));
1794 	pgdat->first_deferred_pfn = ULONG_MAX;
1795 
1796 	/* Only the highest zone is deferred so find it */
1797 	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1798 		zone = pgdat->node_zones + zid;
1799 		if (first_init_pfn < zone_end_pfn(zone))
1800 			break;
1801 	}
1802 
1803 	/* If the zone is empty somebody else may have cleared out the zone */
1804 	if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
1805 						 first_init_pfn))
1806 		goto zone_empty;
1807 
1808 	/*
1809 	 * Initialize and free pages in MAX_ORDER sized increments so
1810 	 * that we can avoid introducing any issues with the buddy
1811 	 * allocator.
1812 	 */
1813 	while (spfn < epfn)
1814 		nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
1815 zone_empty:
1816 	pgdat_resize_unlock(pgdat, &flags);
1817 
1818 	/* Sanity check that the next zone really is unpopulated */
1819 	WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));
1820 
1821 	pr_info("node %d initialised, %lu pages in %ums\n",
1822 		pgdat->node_id,	nr_pages, jiffies_to_msecs(jiffies - start));
1823 
1824 	pgdat_init_report_one_done();
1825 	return 0;
1826 }
1827 
1828 /*
1829  * If this zone has deferred pages, try to grow it by initializing enough
1830  * deferred pages to satisfy the allocation specified by order, rounded up to
1831  * the nearest PAGES_PER_SECTION boundary.  So we're adding memory in increments
1832  * of SECTION_SIZE bytes by initializing struct pages in increments of
1833  * PAGES_PER_SECTION * sizeof(struct page) bytes.
1834  *
1835  * Return true when zone was grown, otherwise return false. We return true even
1836  * when we grow less than requested, to let the caller decide if there are
1837  * enough pages to satisfy the allocation.
1838  *
1839  * Note: We use noinline because this function is needed only during boot, and
1840  * it is called from a __ref function _deferred_grow_zone. This way we are
1841  * making sure that it is not inlined into permanent text section.
1842  */
1843 static noinline bool __init
1844 deferred_grow_zone(struct zone *zone, unsigned int order)
1845 {
1846 	unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION);
1847 	pg_data_t *pgdat = zone->zone_pgdat;
1848 	unsigned long first_deferred_pfn = pgdat->first_deferred_pfn;
1849 	unsigned long spfn, epfn, flags;
1850 	unsigned long nr_pages = 0;
1851 	u64 i;
1852 
1853 	/* Only the last zone may have deferred pages */
1854 	if (zone_end_pfn(zone) != pgdat_end_pfn(pgdat))
1855 		return false;
1856 
1857 	pgdat_resize_lock(pgdat, &flags);
1858 
1859 	/*
1860 	 * If deferred pages have been initialized while we were waiting for
1861 	 * the lock, return true, as the zone was grown.  The caller will retry
1862 	 * this zone.  We won't return to this function since the caller also
1863 	 * has this static branch.
1864 	 */
1865 	if (!static_branch_unlikely(&deferred_pages)) {
1866 		pgdat_resize_unlock(pgdat, &flags);
1867 		return true;
1868 	}
1869 
1870 	/*
1871 	 * If someone grew this zone while we were waiting for spinlock, return
1872 	 * true, as there might be enough pages already.
1873 	 */
1874 	if (first_deferred_pfn != pgdat->first_deferred_pfn) {
1875 		pgdat_resize_unlock(pgdat, &flags);
1876 		return true;
1877 	}
1878 
1879 	/* If the zone is empty somebody else may have cleared out the zone */
1880 	if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
1881 						 first_deferred_pfn)) {
1882 		pgdat->first_deferred_pfn = ULONG_MAX;
1883 		pgdat_resize_unlock(pgdat, &flags);
1884 		/* Retry only once. */
1885 		return first_deferred_pfn != ULONG_MAX;
1886 	}
1887 
1888 	/*
1889 	 * Initialize and free pages in MAX_ORDER sized increments so
1890 	 * that we can avoid introducing any issues with the buddy
1891 	 * allocator.
1892 	 */
1893 	while (spfn < epfn) {
1894 		/* update our first deferred PFN for this section */
1895 		first_deferred_pfn = spfn;
1896 
1897 		nr_pages += deferred_init_maxorder(&i, zone, &spfn, &epfn);
1898 
1899 		/* We should only stop along section boundaries */
1900 		if ((first_deferred_pfn ^ spfn) < PAGES_PER_SECTION)
1901 			continue;
1902 
1903 		/* If our quota has been met we can stop here */
1904 		if (nr_pages >= nr_pages_needed)
1905 			break;
1906 	}
1907 
1908 	pgdat->first_deferred_pfn = spfn;
1909 	pgdat_resize_unlock(pgdat, &flags);
1910 
1911 	return nr_pages > 0;
1912 }
1913 
1914 /*
1915  * deferred_grow_zone() is __init, but it is called from
1916  * get_page_from_freelist() during early boot until deferred_pages permanently
1917  * disables this call. This is why we have refdata wrapper to avoid warning,
1918  * and to ensure that the function body gets unloaded.
1919  */
1920 static bool __ref
1921 _deferred_grow_zone(struct zone *zone, unsigned int order)
1922 {
1923 	return deferred_grow_zone(zone, order);
1924 }
1925 
1926 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1927 
1928 void __init page_alloc_init_late(void)
1929 {
1930 	struct zone *zone;
1931 	int nid;
1932 
1933 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1934 
1935 	/* There will be num_node_state(N_MEMORY) threads */
1936 	atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY));
1937 	for_each_node_state(nid, N_MEMORY) {
1938 		kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid);
1939 	}
1940 
1941 	/* Block until all are initialised */
1942 	wait_for_completion(&pgdat_init_all_done_comp);
1943 
1944 	/*
1945 	 * We initialized the rest of the deferred pages.  Permanently disable
1946 	 * on-demand struct page initialization.
1947 	 */
1948 	static_branch_disable(&deferred_pages);
1949 
1950 	/* Reinit limits that are based on free pages after the kernel is up */
1951 	files_maxfiles_init();
1952 #endif
1953 
1954 	/* Discard memblock private memory */
1955 	memblock_discard();
1956 
1957 	for_each_node_state(nid, N_MEMORY)
1958 		shuffle_free_memory(NODE_DATA(nid));
1959 
1960 	for_each_populated_zone(zone)
1961 		set_zone_contiguous(zone);
1962 
1963 #ifdef CONFIG_DEBUG_PAGEALLOC
1964 	init_debug_guardpage();
1965 #endif
1966 }
1967 
1968 #ifdef CONFIG_CMA
1969 /* Free whole pageblock and set its migration type to MIGRATE_CMA. */
1970 void __init init_cma_reserved_pageblock(struct page *page)
1971 {
1972 	unsigned i = pageblock_nr_pages;
1973 	struct page *p = page;
1974 
1975 	do {
1976 		__ClearPageReserved(p);
1977 		set_page_count(p, 0);
1978 	} while (++p, --i);
1979 
1980 	set_pageblock_migratetype(page, MIGRATE_CMA);
1981 
1982 	if (pageblock_order >= MAX_ORDER) {
1983 		i = pageblock_nr_pages;
1984 		p = page;
1985 		do {
1986 			set_page_refcounted(p);
1987 			__free_pages(p, MAX_ORDER - 1);
1988 			p += MAX_ORDER_NR_PAGES;
1989 		} while (i -= MAX_ORDER_NR_PAGES);
1990 	} else {
1991 		set_page_refcounted(page);
1992 		__free_pages(page, pageblock_order);
1993 	}
1994 
1995 	adjust_managed_page_count(page, pageblock_nr_pages);
1996 }
1997 #endif
1998 
1999 /*
2000  * The order of subdivision here is critical for the IO subsystem.
2001  * Please do not alter this order without good reasons and regression
2002  * testing. Specifically, as large blocks of memory are subdivided,
2003  * the order in which smaller blocks are delivered depends on the order
2004  * they're subdivided in this function. This is the primary factor
2005  * influencing the order in which pages are delivered to the IO
2006  * subsystem according to empirical testing, and this is also justified
2007  * by considering the behavior of a buddy system containing a single
2008  * large block of memory acted on by a series of small allocations.
2009  * This behavior is a critical factor in sglist merging's success.
2010  *
2011  * -- nyc
2012  */
2013 static inline void expand(struct zone *zone, struct page *page,
2014 	int low, int high, struct free_area *area,
2015 	int migratetype)
2016 {
2017 	unsigned long size = 1 << high;
2018 
2019 	while (high > low) {
2020 		area--;
2021 		high--;
2022 		size >>= 1;
2023 		VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
2024 
2025 		/*
2026 		 * Mark as guard pages (or page), that will allow to
2027 		 * merge back to allocator when buddy will be freed.
2028 		 * Corresponding page table entries will not be touched,
2029 		 * pages will stay not present in virtual address space
2030 		 */
2031 		if (set_page_guard(zone, &page[size], high, migratetype))
2032 			continue;
2033 
2034 		add_to_free_area(&page[size], area, migratetype);
2035 		set_page_order(&page[size], high);
2036 	}
2037 }
2038 
2039 static void check_new_page_bad(struct page *page)
2040 {
2041 	const char *bad_reason = NULL;
2042 	unsigned long bad_flags = 0;
2043 
2044 	if (unlikely(atomic_read(&page->_mapcount) != -1))
2045 		bad_reason = "nonzero mapcount";
2046 	if (unlikely(page->mapping != NULL))
2047 		bad_reason = "non-NULL mapping";
2048 	if (unlikely(page_ref_count(page) != 0))
2049 		bad_reason = "nonzero _refcount";
2050 	if (unlikely(page->flags & __PG_HWPOISON)) {
2051 		bad_reason = "HWPoisoned (hardware-corrupted)";
2052 		bad_flags = __PG_HWPOISON;
2053 		/* Don't complain about hwpoisoned pages */
2054 		page_mapcount_reset(page); /* remove PageBuddy */
2055 		return;
2056 	}
2057 	if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
2058 		bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
2059 		bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
2060 	}
2061 #ifdef CONFIG_MEMCG
2062 	if (unlikely(page->mem_cgroup))
2063 		bad_reason = "page still charged to cgroup";
2064 #endif
2065 	bad_page(page, bad_reason, bad_flags);
2066 }
2067 
2068 /*
2069  * This page is about to be returned from the page allocator
2070  */
2071 static inline int check_new_page(struct page *page)
2072 {
2073 	if (likely(page_expected_state(page,
2074 				PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON)))
2075 		return 0;
2076 
2077 	check_new_page_bad(page);
2078 	return 1;
2079 }
2080 
2081 static inline bool free_pages_prezeroed(void)
2082 {
2083 	return (IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) &&
2084 		page_poisoning_enabled()) || want_init_on_free();
2085 }
2086 
2087 #ifdef CONFIG_DEBUG_VM
2088 /*
2089  * With DEBUG_VM enabled, order-0 pages are checked for expected state when
2090  * being allocated from pcp lists. With debug_pagealloc also enabled, they are
2091  * also checked when pcp lists are refilled from the free lists.
2092  */
2093 static inline bool check_pcp_refill(struct page *page)
2094 {
2095 	if (debug_pagealloc_enabled())
2096 		return check_new_page(page);
2097 	else
2098 		return false;
2099 }
2100 
2101 static inline bool check_new_pcp(struct page *page)
2102 {
2103 	return check_new_page(page);
2104 }
2105 #else
2106 /*
2107  * With DEBUG_VM disabled, free order-0 pages are checked for expected state
2108  * when pcp lists are being refilled from the free lists. With debug_pagealloc
2109  * enabled, they are also checked when being allocated from the pcp lists.
2110  */
2111 static inline bool check_pcp_refill(struct page *page)
2112 {
2113 	return check_new_page(page);
2114 }
2115 static inline bool check_new_pcp(struct page *page)
2116 {
2117 	if (debug_pagealloc_enabled())
2118 		return check_new_page(page);
2119 	else
2120 		return false;
2121 }
2122 #endif /* CONFIG_DEBUG_VM */
2123 
2124 static bool check_new_pages(struct page *page, unsigned int order)
2125 {
2126 	int i;
2127 	for (i = 0; i < (1 << order); i++) {
2128 		struct page *p = page + i;
2129 
2130 		if (unlikely(check_new_page(p)))
2131 			return true;
2132 	}
2133 
2134 	return false;
2135 }
2136 
2137 inline void post_alloc_hook(struct page *page, unsigned int order,
2138 				gfp_t gfp_flags)
2139 {
2140 	set_page_private(page, 0);
2141 	set_page_refcounted(page);
2142 
2143 	arch_alloc_page(page, order);
2144 	if (debug_pagealloc_enabled())
2145 		kernel_map_pages(page, 1 << order, 1);
2146 	kasan_alloc_pages(page, order);
2147 	kernel_poison_pages(page, 1 << order, 1);
2148 	set_page_owner(page, order, gfp_flags);
2149 }
2150 
2151 static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
2152 							unsigned int alloc_flags)
2153 {
2154 	post_alloc_hook(page, order, gfp_flags);
2155 
2156 	if (!free_pages_prezeroed() && want_init_on_alloc(gfp_flags))
2157 		kernel_init_free_pages(page, 1 << order);
2158 
2159 	if (order && (gfp_flags & __GFP_COMP))
2160 		prep_compound_page(page, order);
2161 
2162 	/*
2163 	 * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
2164 	 * allocate the page. The expectation is that the caller is taking
2165 	 * steps that will free more memory. The caller should avoid the page
2166 	 * being used for !PFMEMALLOC purposes.
2167 	 */
2168 	if (alloc_flags & ALLOC_NO_WATERMARKS)
2169 		set_page_pfmemalloc(page);
2170 	else
2171 		clear_page_pfmemalloc(page);
2172 }
2173 
2174 /*
2175  * Go through the free lists for the given migratetype and remove
2176  * the smallest available page from the freelists
2177  */
2178 static __always_inline
2179 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
2180 						int migratetype)
2181 {
2182 	unsigned int current_order;
2183 	struct free_area *area;
2184 	struct page *page;
2185 
2186 	/* Find a page of the appropriate size in the preferred list */
2187 	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
2188 		area = &(zone->free_area[current_order]);
2189 		page = get_page_from_free_area(area, migratetype);
2190 		if (!page)
2191 			continue;
2192 		del_page_from_free_area(page, area);
2193 		expand(zone, page, order, current_order, area, migratetype);
2194 		set_pcppage_migratetype(page, migratetype);
2195 		return page;
2196 	}
2197 
2198 	return NULL;
2199 }
2200 
2201 
2202 /*
2203  * This array describes the order lists are fallen back to when
2204  * the free lists for the desirable migrate type are depleted
2205  */
2206 static int fallbacks[MIGRATE_TYPES][4] = {
2207 	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_TYPES },
2208 	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
2209 	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_TYPES },
2210 #ifdef CONFIG_CMA
2211 	[MIGRATE_CMA]         = { MIGRATE_TYPES }, /* Never used */
2212 #endif
2213 #ifdef CONFIG_MEMORY_ISOLATION
2214 	[MIGRATE_ISOLATE]     = { MIGRATE_TYPES }, /* Never used */
2215 #endif
2216 };
2217 
2218 #ifdef CONFIG_CMA
2219 static __always_inline struct page *__rmqueue_cma_fallback(struct zone *zone,
2220 					unsigned int order)
2221 {
2222 	return __rmqueue_smallest(zone, order, MIGRATE_CMA);
2223 }
2224 #else
2225 static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
2226 					unsigned int order) { return NULL; }
2227 #endif
2228 
2229 /*
2230  * Move the free pages in a range to the free lists of the requested type.
2231  * Note that start_page and end_pages are not aligned on a pageblock
2232  * boundary. If alignment is required, use move_freepages_block()
2233  */
2234 static int move_freepages(struct zone *zone,
2235 			  struct page *start_page, struct page *end_page,
2236 			  int migratetype, int *num_movable)
2237 {
2238 	struct page *page;
2239 	unsigned int order;
2240 	int pages_moved = 0;
2241 
2242 	for (page = start_page; page <= end_page;) {
2243 		if (!pfn_valid_within(page_to_pfn(page))) {
2244 			page++;
2245 			continue;
2246 		}
2247 
2248 		if (!PageBuddy(page)) {
2249 			/*
2250 			 * We assume that pages that could be isolated for
2251 			 * migration are movable. But we don't actually try
2252 			 * isolating, as that would be expensive.
2253 			 */
2254 			if (num_movable &&
2255 					(PageLRU(page) || __PageMovable(page)))
2256 				(*num_movable)++;
2257 
2258 			page++;
2259 			continue;
2260 		}
2261 
2262 		/* Make sure we are not inadvertently changing nodes */
2263 		VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
2264 		VM_BUG_ON_PAGE(page_zone(page) != zone, page);
2265 
2266 		order = page_order(page);
2267 		move_to_free_area(page, &zone->free_area[order], migratetype);
2268 		page += 1 << order;
2269 		pages_moved += 1 << order;
2270 	}
2271 
2272 	return pages_moved;
2273 }
2274 
2275 int move_freepages_block(struct zone *zone, struct page *page,
2276 				int migratetype, int *num_movable)
2277 {
2278 	unsigned long start_pfn, end_pfn;
2279 	struct page *start_page, *end_page;
2280 
2281 	if (num_movable)
2282 		*num_movable = 0;
2283 
2284 	start_pfn = page_to_pfn(page);
2285 	start_pfn = start_pfn & ~(pageblock_nr_pages-1);
2286 	start_page = pfn_to_page(start_pfn);
2287 	end_page = start_page + pageblock_nr_pages - 1;
2288 	end_pfn = start_pfn + pageblock_nr_pages - 1;
2289 
2290 	/* Do not cross zone boundaries */
2291 	if (!zone_spans_pfn(zone, start_pfn))
2292 		start_page = page;
2293 	if (!zone_spans_pfn(zone, end_pfn))
2294 		return 0;
2295 
2296 	return move_freepages(zone, start_page, end_page, migratetype,
2297 								num_movable);
2298 }
2299 
2300 static void change_pageblock_range(struct page *pageblock_page,
2301 					int start_order, int migratetype)
2302 {
2303 	int nr_pageblocks = 1 << (start_order - pageblock_order);
2304 
2305 	while (nr_pageblocks--) {
2306 		set_pageblock_migratetype(pageblock_page, migratetype);
2307 		pageblock_page += pageblock_nr_pages;
2308 	}
2309 }
2310 
2311 /*
2312  * When we are falling back to another migratetype during allocation, try to
2313  * steal extra free pages from the same pageblocks to satisfy further
2314  * allocations, instead of polluting multiple pageblocks.
2315  *
2316  * If we are stealing a relatively large buddy page, it is likely there will
2317  * be more free pages in the pageblock, so try to steal them all. For
2318  * reclaimable and unmovable allocations, we steal regardless of page size,
2319  * as fragmentation caused by those allocations polluting movable pageblocks
2320  * is worse than movable allocations stealing from unmovable and reclaimable
2321  * pageblocks.
2322  */
2323 static bool can_steal_fallback(unsigned int order, int start_mt)
2324 {
2325 	/*
2326 	 * Leaving this order check is intended, although there is
2327 	 * relaxed order check in next check. The reason is that
2328 	 * we can actually steal whole pageblock if this condition met,
2329 	 * but, below check doesn't guarantee it and that is just heuristic
2330 	 * so could be changed anytime.
2331 	 */
2332 	if (order >= pageblock_order)
2333 		return true;
2334 
2335 	if (order >= pageblock_order / 2 ||
2336 		start_mt == MIGRATE_RECLAIMABLE ||
2337 		start_mt == MIGRATE_UNMOVABLE ||
2338 		page_group_by_mobility_disabled)
2339 		return true;
2340 
2341 	return false;
2342 }
2343 
2344 static inline void boost_watermark(struct zone *zone)
2345 {
2346 	unsigned long max_boost;
2347 
2348 	if (!watermark_boost_factor)
2349 		return;
2350 
2351 	max_boost = mult_frac(zone->_watermark[WMARK_HIGH],
2352 			watermark_boost_factor, 10000);
2353 
2354 	/*
2355 	 * high watermark may be uninitialised if fragmentation occurs
2356 	 * very early in boot so do not boost. We do not fall
2357 	 * through and boost by pageblock_nr_pages as failing
2358 	 * allocations that early means that reclaim is not going
2359 	 * to help and it may even be impossible to reclaim the
2360 	 * boosted watermark resulting in a hang.
2361 	 */
2362 	if (!max_boost)
2363 		return;
2364 
2365 	max_boost = max(pageblock_nr_pages, max_boost);
2366 
2367 	zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages,
2368 		max_boost);
2369 }
2370 
2371 /*
2372  * This function implements actual steal behaviour. If order is large enough,
2373  * we can steal whole pageblock. If not, we first move freepages in this
2374  * pageblock to our migratetype and determine how many already-allocated pages
2375  * are there in the pageblock with a compatible migratetype. If at least half
2376  * of pages are free or compatible, we can change migratetype of the pageblock
2377  * itself, so pages freed in the future will be put on the correct free list.
2378  */
2379 static void steal_suitable_fallback(struct zone *zone, struct page *page,
2380 		unsigned int alloc_flags, int start_type, bool whole_block)
2381 {
2382 	unsigned int current_order = page_order(page);
2383 	struct free_area *area;
2384 	int free_pages, movable_pages, alike_pages;
2385 	int old_block_type;
2386 
2387 	old_block_type = get_pageblock_migratetype(page);
2388 
2389 	/*
2390 	 * This can happen due to races and we want to prevent broken
2391 	 * highatomic accounting.
2392 	 */
2393 	if (is_migrate_highatomic(old_block_type))
2394 		goto single_page;
2395 
2396 	/* Take ownership for orders >= pageblock_order */
2397 	if (current_order >= pageblock_order) {
2398 		change_pageblock_range(page, current_order, start_type);
2399 		goto single_page;
2400 	}
2401 
2402 	/*
2403 	 * Boost watermarks to increase reclaim pressure to reduce the
2404 	 * likelihood of future fallbacks. Wake kswapd now as the node
2405 	 * may be balanced overall and kswapd will not wake naturally.
2406 	 */
2407 	boost_watermark(zone);
2408 	if (alloc_flags & ALLOC_KSWAPD)
2409 		set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
2410 
2411 	/* We are not allowed to try stealing from the whole block */
2412 	if (!whole_block)
2413 		goto single_page;
2414 
2415 	free_pages = move_freepages_block(zone, page, start_type,
2416 						&movable_pages);
2417 	/*
2418 	 * Determine how many pages are compatible with our allocation.
2419 	 * For movable allocation, it's the number of movable pages which
2420 	 * we just obtained. For other types it's a bit more tricky.
2421 	 */
2422 	if (start_type == MIGRATE_MOVABLE) {
2423 		alike_pages = movable_pages;
2424 	} else {
2425 		/*
2426 		 * If we are falling back a RECLAIMABLE or UNMOVABLE allocation
2427 		 * to MOVABLE pageblock, consider all non-movable pages as
2428 		 * compatible. If it's UNMOVABLE falling back to RECLAIMABLE or
2429 		 * vice versa, be conservative since we can't distinguish the
2430 		 * exact migratetype of non-movable pages.
2431 		 */
2432 		if (old_block_type == MIGRATE_MOVABLE)
2433 			alike_pages = pageblock_nr_pages
2434 						- (free_pages + movable_pages);
2435 		else
2436 			alike_pages = 0;
2437 	}
2438 
2439 	/* moving whole block can fail due to zone boundary conditions */
2440 	if (!free_pages)
2441 		goto single_page;
2442 
2443 	/*
2444 	 * If a sufficient number of pages in the block are either free or of
2445 	 * comparable migratability as our allocation, claim the whole block.
2446 	 */
2447 	if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||
2448 			page_group_by_mobility_disabled)
2449 		set_pageblock_migratetype(page, start_type);
2450 
2451 	return;
2452 
2453 single_page:
2454 	area = &zone->free_area[current_order];
2455 	move_to_free_area(page, area, start_type);
2456 }
2457 
2458 /*
2459  * Check whether there is a suitable fallback freepage with requested order.
2460  * If only_stealable is true, this function returns fallback_mt only if
2461  * we can steal other freepages all together. This would help to reduce
2462  * fragmentation due to mixed migratetype pages in one pageblock.
2463  */
2464 int find_suitable_fallback(struct free_area *area, unsigned int order,
2465 			int migratetype, bool only_stealable, bool *can_steal)
2466 {
2467 	int i;
2468 	int fallback_mt;
2469 
2470 	if (area->nr_free == 0)
2471 		return -1;
2472 
2473 	*can_steal = false;
2474 	for (i = 0;; i++) {
2475 		fallback_mt = fallbacks[migratetype][i];
2476 		if (fallback_mt == MIGRATE_TYPES)
2477 			break;
2478 
2479 		if (free_area_empty(area, fallback_mt))
2480 			continue;
2481 
2482 		if (can_steal_fallback(order, migratetype))
2483 			*can_steal = true;
2484 
2485 		if (!only_stealable)
2486 			return fallback_mt;
2487 
2488 		if (*can_steal)
2489 			return fallback_mt;
2490 	}
2491 
2492 	return -1;
2493 }
2494 
2495 /*
2496  * Reserve a pageblock for exclusive use of high-order atomic allocations if
2497  * there are no empty page blocks that contain a page with a suitable order
2498  */
2499 static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
2500 				unsigned int alloc_order)
2501 {
2502 	int mt;
2503 	unsigned long max_managed, flags;
2504 
2505 	/*
2506 	 * Limit the number reserved to 1 pageblock or roughly 1% of a zone.
2507 	 * Check is race-prone but harmless.
2508 	 */
2509 	max_managed = (zone_managed_pages(zone) / 100) + pageblock_nr_pages;
2510 	if (zone->nr_reserved_highatomic >= max_managed)
2511 		return;
2512 
2513 	spin_lock_irqsave(&zone->lock, flags);
2514 
2515 	/* Recheck the nr_reserved_highatomic limit under the lock */
2516 	if (zone->nr_reserved_highatomic >= max_managed)
2517 		goto out_unlock;
2518 
2519 	/* Yoink! */
2520 	mt = get_pageblock_migratetype(page);
2521 	if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt)
2522 	    && !is_migrate_cma(mt)) {
2523 		zone->nr_reserved_highatomic += pageblock_nr_pages;
2524 		set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
2525 		move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL);
2526 	}
2527 
2528 out_unlock:
2529 	spin_unlock_irqrestore(&zone->lock, flags);
2530 }
2531 
2532 /*
2533  * Used when an allocation is about to fail under memory pressure. This
2534  * potentially hurts the reliability of high-order allocations when under
2535  * intense memory pressure but failed atomic allocations should be easier
2536  * to recover from than an OOM.
2537  *
2538  * If @force is true, try to unreserve a pageblock even though highatomic
2539  * pageblock is exhausted.
2540  */
2541 static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
2542 						bool force)
2543 {
2544 	struct zonelist *zonelist = ac->zonelist;
2545 	unsigned long flags;
2546 	struct zoneref *z;
2547 	struct zone *zone;
2548 	struct page *page;
2549 	int order;
2550 	bool ret;
2551 
2552 	for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->high_zoneidx,
2553 								ac->nodemask) {
2554 		/*
2555 		 * Preserve at least one pageblock unless memory pressure
2556 		 * is really high.
2557 		 */
2558 		if (!force && zone->nr_reserved_highatomic <=
2559 					pageblock_nr_pages)
2560 			continue;
2561 
2562 		spin_lock_irqsave(&zone->lock, flags);
2563 		for (order = 0; order < MAX_ORDER; order++) {
2564 			struct free_area *area = &(zone->free_area[order]);
2565 
2566 			page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
2567 			if (!page)
2568 				continue;
2569 
2570 			/*
2571 			 * In page freeing path, migratetype change is racy so
2572 			 * we can counter several free pages in a pageblock
2573 			 * in this loop althoug we changed the pageblock type
2574 			 * from highatomic to ac->migratetype. So we should
2575 			 * adjust the count once.
2576 			 */
2577 			if (is_migrate_highatomic_page(page)) {
2578 				/*
2579 				 * It should never happen but changes to
2580 				 * locking could inadvertently allow a per-cpu
2581 				 * drain to add pages to MIGRATE_HIGHATOMIC
2582 				 * while unreserving so be safe and watch for
2583 				 * underflows.
2584 				 */
2585 				zone->nr_reserved_highatomic -= min(
2586 						pageblock_nr_pages,
2587 						zone->nr_reserved_highatomic);
2588 			}
2589 
2590 			/*
2591 			 * Convert to ac->migratetype and avoid the normal
2592 			 * pageblock stealing heuristics. Minimally, the caller
2593 			 * is doing the work and needs the pages. More
2594 			 * importantly, if the block was always converted to
2595 			 * MIGRATE_UNMOVABLE or another type then the number
2596 			 * of pageblocks that cannot be completely freed
2597 			 * may increase.
2598 			 */
2599 			set_pageblock_migratetype(page, ac->migratetype);
2600 			ret = move_freepages_block(zone, page, ac->migratetype,
2601 									NULL);
2602 			if (ret) {
2603 				spin_unlock_irqrestore(&zone->lock, flags);
2604 				return ret;
2605 			}
2606 		}
2607 		spin_unlock_irqrestore(&zone->lock, flags);
2608 	}
2609 
2610 	return false;
2611 }
2612 
2613 /*
2614  * Try finding a free buddy page on the fallback list and put it on the free
2615  * list of requested migratetype, possibly along with other pages from the same
2616  * block, depending on fragmentation avoidance heuristics. Returns true if
2617  * fallback was found so that __rmqueue_smallest() can grab it.
2618  *
2619  * The use of signed ints for order and current_order is a deliberate
2620  * deviation from the rest of this file, to make the for loop
2621  * condition simpler.
2622  */
2623 static __always_inline bool
2624 __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
2625 						unsigned int alloc_flags)
2626 {
2627 	struct free_area *area;
2628 	int current_order;
2629 	int min_order = order;
2630 	struct page *page;
2631 	int fallback_mt;
2632 	bool can_steal;
2633 
2634 	/*
2635 	 * Do not steal pages from freelists belonging to other pageblocks
2636 	 * i.e. orders < pageblock_order. If there are no local zones free,
2637 	 * the zonelists will be reiterated without ALLOC_NOFRAGMENT.
2638 	 */
2639 	if (alloc_flags & ALLOC_NOFRAGMENT)
2640 		min_order = pageblock_order;
2641 
2642 	/*
2643 	 * Find the largest available free page in the other list. This roughly
2644 	 * approximates finding the pageblock with the most free pages, which
2645 	 * would be too costly to do exactly.
2646 	 */
2647 	for (current_order = MAX_ORDER - 1; current_order >= min_order;
2648 				--current_order) {
2649 		area = &(zone->free_area[current_order]);
2650 		fallback_mt = find_suitable_fallback(area, current_order,
2651 				start_migratetype, false, &can_steal);
2652 		if (fallback_mt == -1)
2653 			continue;
2654 
2655 		/*
2656 		 * We cannot steal all free pages from the pageblock and the
2657 		 * requested migratetype is movable. In that case it's better to
2658 		 * steal and split the smallest available page instead of the
2659 		 * largest available page, because even if the next movable
2660 		 * allocation falls back into a different pageblock than this
2661 		 * one, it won't cause permanent fragmentation.
2662 		 */
2663 		if (!can_steal && start_migratetype == MIGRATE_MOVABLE
2664 					&& current_order > order)
2665 			goto find_smallest;
2666 
2667 		goto do_steal;
2668 	}
2669 
2670 	return false;
2671 
2672 find_smallest:
2673 	for (current_order = order; current_order < MAX_ORDER;
2674 							current_order++) {
2675 		area = &(zone->free_area[current_order]);
2676 		fallback_mt = find_suitable_fallback(area, current_order,
2677 				start_migratetype, false, &can_steal);
2678 		if (fallback_mt != -1)
2679 			break;
2680 	}
2681 
2682 	/*
2683 	 * This should not happen - we already found a suitable fallback
2684 	 * when looking for the largest page.
2685 	 */
2686 	VM_BUG_ON(current_order == MAX_ORDER);
2687 
2688 do_steal:
2689 	page = get_page_from_free_area(area, fallback_mt);
2690 
2691 	steal_suitable_fallback(zone, page, alloc_flags, start_migratetype,
2692 								can_steal);
2693 
2694 	trace_mm_page_alloc_extfrag(page, order, current_order,
2695 		start_migratetype, fallback_mt);
2696 
2697 	return true;
2698 
2699 }
2700 
2701 /*
2702  * Do the hard work of removing an element from the buddy allocator.
2703  * Call me with the zone->lock already held.
2704  */
2705 static __always_inline struct page *
2706 __rmqueue(struct zone *zone, unsigned int order, int migratetype,
2707 						unsigned int alloc_flags)
2708 {
2709 	struct page *page;
2710 
2711 retry:
2712 	page = __rmqueue_smallest(zone, order, migratetype);
2713 	if (unlikely(!page)) {
2714 		if (migratetype == MIGRATE_MOVABLE)
2715 			page = __rmqueue_cma_fallback(zone, order);
2716 
2717 		if (!page && __rmqueue_fallback(zone, order, migratetype,
2718 								alloc_flags))
2719 			goto retry;
2720 	}
2721 
2722 	trace_mm_page_alloc_zone_locked(page, order, migratetype);
2723 	return page;
2724 }
2725 
2726 /*
2727  * Obtain a specified number of elements from the buddy allocator, all under
2728  * a single hold of the lock, for efficiency.  Add them to the supplied list.
2729  * Returns the number of new pages which were placed at *list.
2730  */
2731 static int rmqueue_bulk(struct zone *zone, unsigned int order,
2732 			unsigned long count, struct list_head *list,
2733 			int migratetype, unsigned int alloc_flags)
2734 {
2735 	int i, alloced = 0;
2736 
2737 	spin_lock(&zone->lock);
2738 	for (i = 0; i < count; ++i) {
2739 		struct page *page = __rmqueue(zone, order, migratetype,
2740 								alloc_flags);
2741 		if (unlikely(page == NULL))
2742 			break;
2743 
2744 		if (unlikely(check_pcp_refill(page)))
2745 			continue;
2746 
2747 		/*
2748 		 * Split buddy pages returned by expand() are received here in
2749 		 * physical page order. The page is added to the tail of
2750 		 * caller's list. From the callers perspective, the linked list
2751 		 * is ordered by page number under some conditions. This is
2752 		 * useful for IO devices that can forward direction from the
2753 		 * head, thus also in the physical page order. This is useful
2754 		 * for IO devices that can merge IO requests if the physical
2755 		 * pages are ordered properly.
2756 		 */
2757 		list_add_tail(&page->lru, list);
2758 		alloced++;
2759 		if (is_migrate_cma(get_pcppage_migratetype(page)))
2760 			__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
2761 					      -(1 << order));
2762 	}
2763 
2764 	/*
2765 	 * i pages were removed from the buddy list even if some leak due
2766 	 * to check_pcp_refill failing so adjust NR_FREE_PAGES based
2767 	 * on i. Do not confuse with 'alloced' which is the number of
2768 	 * pages added to the pcp list.
2769 	 */
2770 	__mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
2771 	spin_unlock(&zone->lock);
2772 	return alloced;
2773 }
2774 
2775 #ifdef CONFIG_NUMA
2776 /*
2777  * Called from the vmstat counter updater to drain pagesets of this
2778  * currently executing processor on remote nodes after they have
2779  * expired.
2780  *
2781  * Note that this function must be called with the thread pinned to
2782  * a single processor.
2783  */
2784 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
2785 {
2786 	unsigned long flags;
2787 	int to_drain, batch;
2788 
2789 	local_irq_save(flags);
2790 	batch = READ_ONCE(pcp->batch);
2791 	to_drain = min(pcp->count, batch);
2792 	if (to_drain > 0)
2793 		free_pcppages_bulk(zone, to_drain, pcp);
2794 	local_irq_restore(flags);
2795 }
2796 #endif
2797 
2798 /*
2799  * Drain pcplists of the indicated processor and zone.
2800  *
2801  * The processor must either be the current processor and the
2802  * thread pinned to the current processor or a processor that
2803  * is not online.
2804  */
2805 static void drain_pages_zone(unsigned int cpu, struct zone *zone)
2806 {
2807 	unsigned long flags;
2808 	struct per_cpu_pageset *pset;
2809 	struct per_cpu_pages *pcp;
2810 
2811 	local_irq_save(flags);
2812 	pset = per_cpu_ptr(zone->pageset, cpu);
2813 
2814 	pcp = &pset->pcp;
2815 	if (pcp->count)
2816 		free_pcppages_bulk(zone, pcp->count, pcp);
2817 	local_irq_restore(flags);
2818 }
2819 
2820 /*
2821  * Drain pcplists of all zones on the indicated processor.
2822  *
2823  * The processor must either be the current processor and the
2824  * thread pinned to the current processor or a processor that
2825  * is not online.
2826  */
2827 static void drain_pages(unsigned int cpu)
2828 {
2829 	struct zone *zone;
2830 
2831 	for_each_populated_zone(zone) {
2832 		drain_pages_zone(cpu, zone);
2833 	}
2834 }
2835 
2836 /*
2837  * Spill all of this CPU's per-cpu pages back into the buddy allocator.
2838  *
2839  * The CPU has to be pinned. When zone parameter is non-NULL, spill just
2840  * the single zone's pages.
2841  */
2842 void drain_local_pages(struct zone *zone)
2843 {
2844 	int cpu = smp_processor_id();
2845 
2846 	if (zone)
2847 		drain_pages_zone(cpu, zone);
2848 	else
2849 		drain_pages(cpu);
2850 }
2851 
2852 static void drain_local_pages_wq(struct work_struct *work)
2853 {
2854 	struct pcpu_drain *drain;
2855 
2856 	drain = container_of(work, struct pcpu_drain, work);
2857 
2858 	/*
2859 	 * drain_all_pages doesn't use proper cpu hotplug protection so
2860 	 * we can race with cpu offline when the WQ can move this from
2861 	 * a cpu pinned worker to an unbound one. We can operate on a different
2862 	 * cpu which is allright but we also have to make sure to not move to
2863 	 * a different one.
2864 	 */
2865 	preempt_disable();
2866 	drain_local_pages(drain->zone);
2867 	preempt_enable();
2868 }
2869 
2870 /*
2871  * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
2872  *
2873  * When zone parameter is non-NULL, spill just the single zone's pages.
2874  *
2875  * Note that this can be extremely slow as the draining happens in a workqueue.
2876  */
2877 void drain_all_pages(struct zone *zone)
2878 {
2879 	int cpu;
2880 
2881 	/*
2882 	 * Allocate in the BSS so we wont require allocation in
2883 	 * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
2884 	 */
2885 	static cpumask_t cpus_with_pcps;
2886 
2887 	/*
2888 	 * Make sure nobody triggers this path before mm_percpu_wq is fully
2889 	 * initialized.
2890 	 */
2891 	if (WARN_ON_ONCE(!mm_percpu_wq))
2892 		return;
2893 
2894 	/*
2895 	 * Do not drain if one is already in progress unless it's specific to
2896 	 * a zone. Such callers are primarily CMA and memory hotplug and need
2897 	 * the drain to be complete when the call returns.
2898 	 */
2899 	if (unlikely(!mutex_trylock(&pcpu_drain_mutex))) {
2900 		if (!zone)
2901 			return;
2902 		mutex_lock(&pcpu_drain_mutex);
2903 	}
2904 
2905 	/*
2906 	 * We don't care about racing with CPU hotplug event
2907 	 * as offline notification will cause the notified
2908 	 * cpu to drain that CPU pcps and on_each_cpu_mask
2909 	 * disables preemption as part of its processing
2910 	 */
2911 	for_each_online_cpu(cpu) {
2912 		struct per_cpu_pageset *pcp;
2913 		struct zone *z;
2914 		bool has_pcps = false;
2915 
2916 		if (zone) {
2917 			pcp = per_cpu_ptr(zone->pageset, cpu);
2918 			if (pcp->pcp.count)
2919 				has_pcps = true;
2920 		} else {
2921 			for_each_populated_zone(z) {
2922 				pcp = per_cpu_ptr(z->pageset, cpu);
2923 				if (pcp->pcp.count) {
2924 					has_pcps = true;
2925 					break;
2926 				}
2927 			}
2928 		}
2929 
2930 		if (has_pcps)
2931 			cpumask_set_cpu(cpu, &cpus_with_pcps);
2932 		else
2933 			cpumask_clear_cpu(cpu, &cpus_with_pcps);
2934 	}
2935 
2936 	for_each_cpu(cpu, &cpus_with_pcps) {
2937 		struct pcpu_drain *drain = per_cpu_ptr(&pcpu_drain, cpu);
2938 
2939 		drain->zone = zone;
2940 		INIT_WORK(&drain->work, drain_local_pages_wq);
2941 		queue_work_on(cpu, mm_percpu_wq, &drain->work);
2942 	}
2943 	for_each_cpu(cpu, &cpus_with_pcps)
2944 		flush_work(&per_cpu_ptr(&pcpu_drain, cpu)->work);
2945 
2946 	mutex_unlock(&pcpu_drain_mutex);
2947 }
2948 
2949 #ifdef CONFIG_HIBERNATION
2950 
2951 /*
2952  * Touch the watchdog for every WD_PAGE_COUNT pages.
2953  */
2954 #define WD_PAGE_COUNT	(128*1024)
2955 
2956 void mark_free_pages(struct zone *zone)
2957 {
2958 	unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
2959 	unsigned long flags;
2960 	unsigned int order, t;
2961 	struct page *page;
2962 
2963 	if (zone_is_empty(zone))
2964 		return;
2965 
2966 	spin_lock_irqsave(&zone->lock, flags);
2967 
2968 	max_zone_pfn = zone_end_pfn(zone);
2969 	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
2970 		if (pfn_valid(pfn)) {
2971 			page = pfn_to_page(pfn);
2972 
2973 			if (!--page_count) {
2974 				touch_nmi_watchdog();
2975 				page_count = WD_PAGE_COUNT;
2976 			}
2977 
2978 			if (page_zone(page) != zone)
2979 				continue;
2980 
2981 			if (!swsusp_page_is_forbidden(page))
2982 				swsusp_unset_page_free(page);
2983 		}
2984 
2985 	for_each_migratetype_order(order, t) {
2986 		list_for_each_entry(page,
2987 				&zone->free_area[order].free_list[t], lru) {
2988 			unsigned long i;
2989 
2990 			pfn = page_to_pfn(page);
2991 			for (i = 0; i < (1UL << order); i++) {
2992 				if (!--page_count) {
2993 					touch_nmi_watchdog();
2994 					page_count = WD_PAGE_COUNT;
2995 				}
2996 				swsusp_set_page_free(pfn_to_page(pfn + i));
2997 			}
2998 		}
2999 	}
3000 	spin_unlock_irqrestore(&zone->lock, flags);
3001 }
3002 #endif /* CONFIG_PM */
3003 
3004 static bool free_unref_page_prepare(struct page *page, unsigned long pfn)
3005 {
3006 	int migratetype;
3007 
3008 	if (!free_pcp_prepare(page))
3009 		return false;
3010 
3011 	migratetype = get_pfnblock_migratetype(page, pfn);
3012 	set_pcppage_migratetype(page, migratetype);
3013 	return true;
3014 }
3015 
3016 static void free_unref_page_commit(struct page *page, unsigned long pfn)
3017 {
3018 	struct zone *zone = page_zone(page);
3019 	struct per_cpu_pages *pcp;
3020 	int migratetype;
3021 
3022 	migratetype = get_pcppage_migratetype(page);
3023 	__count_vm_event(PGFREE);
3024 
3025 	/*
3026 	 * We only track unmovable, reclaimable and movable on pcp lists.
3027 	 * Free ISOLATE pages back to the allocator because they are being
3028 	 * offlined but treat HIGHATOMIC as movable pages so we can get those
3029 	 * areas back if necessary. Otherwise, we may have to free
3030 	 * excessively into the page allocator
3031 	 */
3032 	if (migratetype >= MIGRATE_PCPTYPES) {
3033 		if (unlikely(is_migrate_isolate(migratetype))) {
3034 			free_one_page(zone, page, pfn, 0, migratetype);
3035 			return;
3036 		}
3037 		migratetype = MIGRATE_MOVABLE;
3038 	}
3039 
3040 	pcp = &this_cpu_ptr(zone->pageset)->pcp;
3041 	list_add(&page->lru, &pcp->lists[migratetype]);
3042 	pcp->count++;
3043 	if (pcp->count >= pcp->high) {
3044 		unsigned long batch = READ_ONCE(pcp->batch);
3045 		free_pcppages_bulk(zone, batch, pcp);
3046 	}
3047 }
3048 
3049 /*
3050  * Free a 0-order page
3051  */
3052 void free_unref_page(struct page *page)
3053 {
3054 	unsigned long flags;
3055 	unsigned long pfn = page_to_pfn(page);
3056 
3057 	if (!free_unref_page_prepare(page, pfn))
3058 		return;
3059 
3060 	local_irq_save(flags);
3061 	free_unref_page_commit(page, pfn);
3062 	local_irq_restore(flags);
3063 }
3064 
3065 /*
3066  * Free a list of 0-order pages
3067  */
3068 void free_unref_page_list(struct list_head *list)
3069 {
3070 	struct page *page, *next;
3071 	unsigned long flags, pfn;
3072 	int batch_count = 0;
3073 
3074 	/* Prepare pages for freeing */
3075 	list_for_each_entry_safe(page, next, list, lru) {
3076 		pfn = page_to_pfn(page);
3077 		if (!free_unref_page_prepare(page, pfn))
3078 			list_del(&page->lru);
3079 		set_page_private(page, pfn);
3080 	}
3081 
3082 	local_irq_save(flags);
3083 	list_for_each_entry_safe(page, next, list, lru) {
3084 		unsigned long pfn = page_private(page);
3085 
3086 		set_page_private(page, 0);
3087 		trace_mm_page_free_batched(page);
3088 		free_unref_page_commit(page, pfn);
3089 
3090 		/*
3091 		 * Guard against excessive IRQ disabled times when we get
3092 		 * a large list of pages to free.
3093 		 */
3094 		if (++batch_count == SWAP_CLUSTER_MAX) {
3095 			local_irq_restore(flags);
3096 			batch_count = 0;
3097 			local_irq_save(flags);
3098 		}
3099 	}
3100 	local_irq_restore(flags);
3101 }
3102 
3103 /*
3104  * split_page takes a non-compound higher-order page, and splits it into
3105  * n (1<<order) sub-pages: page[0..n]
3106  * Each sub-page must be freed individually.
3107  *
3108  * Note: this is probably too low level an operation for use in drivers.
3109  * Please consult with lkml before using this in your driver.
3110  */
3111 void split_page(struct page *page, unsigned int order)
3112 {
3113 	int i;
3114 
3115 	VM_BUG_ON_PAGE(PageCompound(page), page);
3116 	VM_BUG_ON_PAGE(!page_count(page), page);
3117 
3118 	for (i = 1; i < (1 << order); i++)
3119 		set_page_refcounted(page + i);
3120 	split_page_owner(page, order);
3121 }
3122 EXPORT_SYMBOL_GPL(split_page);
3123 
3124 int __isolate_free_page(struct page *page, unsigned int order)
3125 {
3126 	struct free_area *area = &page_zone(page)->free_area[order];
3127 	unsigned long watermark;
3128 	struct zone *zone;
3129 	int mt;
3130 
3131 	BUG_ON(!PageBuddy(page));
3132 
3133 	zone = page_zone(page);
3134 	mt = get_pageblock_migratetype(page);
3135 
3136 	if (!is_migrate_isolate(mt)) {
3137 		/*
3138 		 * Obey watermarks as if the page was being allocated. We can
3139 		 * emulate a high-order watermark check with a raised order-0
3140 		 * watermark, because we already know our high-order page
3141 		 * exists.
3142 		 */
3143 		watermark = zone->_watermark[WMARK_MIN] + (1UL << order);
3144 		if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
3145 			return 0;
3146 
3147 		__mod_zone_freepage_state(zone, -(1UL << order), mt);
3148 	}
3149 
3150 	/* Remove page from free list */
3151 
3152 	del_page_from_free_area(page, area);
3153 
3154 	/*
3155 	 * Set the pageblock if the isolated page is at least half of a
3156 	 * pageblock
3157 	 */
3158 	if (order >= pageblock_order - 1) {
3159 		struct page *endpage = page + (1 << order) - 1;
3160 		for (; page < endpage; page += pageblock_nr_pages) {
3161 			int mt = get_pageblock_migratetype(page);
3162 			if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
3163 			    && !is_migrate_highatomic(mt))
3164 				set_pageblock_migratetype(page,
3165 							  MIGRATE_MOVABLE);
3166 		}
3167 	}
3168 
3169 
3170 	return 1UL << order;
3171 }
3172 
3173 /*
3174  * Update NUMA hit/miss statistics
3175  *
3176  * Must be called with interrupts disabled.
3177  */
3178 static inline void zone_statistics(struct zone *preferred_zone, struct zone *z)
3179 {
3180 #ifdef CONFIG_NUMA
3181 	enum numa_stat_item local_stat = NUMA_LOCAL;
3182 
3183 	/* skip numa counters update if numa stats is disabled */
3184 	if (!static_branch_likely(&vm_numa_stat_key))
3185 		return;
3186 
3187 	if (zone_to_nid(z) != numa_node_id())
3188 		local_stat = NUMA_OTHER;
3189 
3190 	if (zone_to_nid(z) == zone_to_nid(preferred_zone))
3191 		__inc_numa_state(z, NUMA_HIT);
3192 	else {
3193 		__inc_numa_state(z, NUMA_MISS);
3194 		__inc_numa_state(preferred_zone, NUMA_FOREIGN);
3195 	}
3196 	__inc_numa_state(z, local_stat);
3197 #endif
3198 }
3199 
3200 /* Remove page from the per-cpu list, caller must protect the list */
3201 static struct page *__rmqueue_pcplist(struct zone *zone, int migratetype,
3202 			unsigned int alloc_flags,
3203 			struct per_cpu_pages *pcp,
3204 			struct list_head *list)
3205 {
3206 	struct page *page;
3207 
3208 	do {
3209 		if (list_empty(list)) {
3210 			pcp->count += rmqueue_bulk(zone, 0,
3211 					pcp->batch, list,
3212 					migratetype, alloc_flags);
3213 			if (unlikely(list_empty(list)))
3214 				return NULL;
3215 		}
3216 
3217 		page = list_first_entry(list, struct page, lru);
3218 		list_del(&page->lru);
3219 		pcp->count--;
3220 	} while (check_new_pcp(page));
3221 
3222 	return page;
3223 }
3224 
3225 /* Lock and remove page from the per-cpu list */
3226 static struct page *rmqueue_pcplist(struct zone *preferred_zone,
3227 			struct zone *zone, gfp_t gfp_flags,
3228 			int migratetype, unsigned int alloc_flags)
3229 {
3230 	struct per_cpu_pages *pcp;
3231 	struct list_head *list;
3232 	struct page *page;
3233 	unsigned long flags;
3234 
3235 	local_irq_save(flags);
3236 	pcp = &this_cpu_ptr(zone->pageset)->pcp;
3237 	list = &pcp->lists[migratetype];
3238 	page = __rmqueue_pcplist(zone,  migratetype, alloc_flags, pcp, list);
3239 	if (page) {
3240 		__count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
3241 		zone_statistics(preferred_zone, zone);
3242 	}
3243 	local_irq_restore(flags);
3244 	return page;
3245 }
3246 
3247 /*
3248  * Allocate a page from the given zone. Use pcplists for order-0 allocations.
3249  */
3250 static inline
3251 struct page *rmqueue(struct zone *preferred_zone,
3252 			struct zone *zone, unsigned int order,
3253 			gfp_t gfp_flags, unsigned int alloc_flags,
3254 			int migratetype)
3255 {
3256 	unsigned long flags;
3257 	struct page *page;
3258 
3259 	if (likely(order == 0)) {
3260 		page = rmqueue_pcplist(preferred_zone, zone, gfp_flags,
3261 					migratetype, alloc_flags);
3262 		goto out;
3263 	}
3264 
3265 	/*
3266 	 * We most definitely don't want callers attempting to
3267 	 * allocate greater than order-1 page units with __GFP_NOFAIL.
3268 	 */
3269 	WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
3270 	spin_lock_irqsave(&zone->lock, flags);
3271 
3272 	do {
3273 		page = NULL;
3274 		if (alloc_flags & ALLOC_HARDER) {
3275 			page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
3276 			if (page)
3277 				trace_mm_page_alloc_zone_locked(page, order, migratetype);
3278 		}
3279 		if (!page)
3280 			page = __rmqueue(zone, order, migratetype, alloc_flags);
3281 	} while (page && check_new_pages(page, order));
3282 	spin_unlock(&zone->lock);
3283 	if (!page)
3284 		goto failed;
3285 	__mod_zone_freepage_state(zone, -(1 << order),
3286 				  get_pcppage_migratetype(page));
3287 
3288 	__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
3289 	zone_statistics(preferred_zone, zone);
3290 	local_irq_restore(flags);
3291 
3292 out:
3293 	/* Separate test+clear to avoid unnecessary atomics */
3294 	if (test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags)) {
3295 		clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
3296 		wakeup_kswapd(zone, 0, 0, zone_idx(zone));
3297 	}
3298 
3299 	VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
3300 	return page;
3301 
3302 failed:
3303 	local_irq_restore(flags);
3304 	return NULL;
3305 }
3306 
3307 #ifdef CONFIG_FAIL_PAGE_ALLOC
3308 
3309 static struct {
3310 	struct fault_attr attr;
3311 
3312 	bool ignore_gfp_highmem;
3313 	bool ignore_gfp_reclaim;
3314 	u32 min_order;
3315 } fail_page_alloc = {
3316 	.attr = FAULT_ATTR_INITIALIZER,
3317 	.ignore_gfp_reclaim = true,
3318 	.ignore_gfp_highmem = true,
3319 	.min_order = 1,
3320 };
3321 
3322 static int __init setup_fail_page_alloc(char *str)
3323 {
3324 	return setup_fault_attr(&fail_page_alloc.attr, str);
3325 }
3326 __setup("fail_page_alloc=", setup_fail_page_alloc);
3327 
3328 static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3329 {
3330 	if (order < fail_page_alloc.min_order)
3331 		return false;
3332 	if (gfp_mask & __GFP_NOFAIL)
3333 		return false;
3334 	if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
3335 		return false;
3336 	if (fail_page_alloc.ignore_gfp_reclaim &&
3337 			(gfp_mask & __GFP_DIRECT_RECLAIM))
3338 		return false;
3339 
3340 	return should_fail(&fail_page_alloc.attr, 1 << order);
3341 }
3342 
3343 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
3344 
3345 static int __init fail_page_alloc_debugfs(void)
3346 {
3347 	umode_t mode = S_IFREG | 0600;
3348 	struct dentry *dir;
3349 
3350 	dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
3351 					&fail_page_alloc.attr);
3352 
3353 	debugfs_create_bool("ignore-gfp-wait", mode, dir,
3354 			    &fail_page_alloc.ignore_gfp_reclaim);
3355 	debugfs_create_bool("ignore-gfp-highmem", mode, dir,
3356 			    &fail_page_alloc.ignore_gfp_highmem);
3357 	debugfs_create_u32("min-order", mode, dir, &fail_page_alloc.min_order);
3358 
3359 	return 0;
3360 }
3361 
3362 late_initcall(fail_page_alloc_debugfs);
3363 
3364 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
3365 
3366 #else /* CONFIG_FAIL_PAGE_ALLOC */
3367 
3368 static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3369 {
3370 	return false;
3371 }
3372 
3373 #endif /* CONFIG_FAIL_PAGE_ALLOC */
3374 
3375 static noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
3376 {
3377 	return __should_fail_alloc_page(gfp_mask, order);
3378 }
3379 ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);
3380 
3381 /*
3382  * Return true if free base pages are above 'mark'. For high-order checks it
3383  * will return true of the order-0 watermark is reached and there is at least
3384  * one free page of a suitable size. Checking now avoids taking the zone lock
3385  * to check in the allocation paths if no pages are free.
3386  */
3387 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
3388 			 int classzone_idx, unsigned int alloc_flags,
3389 			 long free_pages)
3390 {
3391 	long min = mark;
3392 	int o;
3393 	const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM));
3394 
3395 	/* free_pages may go negative - that's OK */
3396 	free_pages -= (1 << order) - 1;
3397 
3398 	if (alloc_flags & ALLOC_HIGH)
3399 		min -= min / 2;
3400 
3401 	/*
3402 	 * If the caller does not have rights to ALLOC_HARDER then subtract
3403 	 * the high-atomic reserves. This will over-estimate the size of the
3404 	 * atomic reserve but it avoids a search.
3405 	 */
3406 	if (likely(!alloc_harder)) {
3407 		free_pages -= z->nr_reserved_highatomic;
3408 	} else {
3409 		/*
3410 		 * OOM victims can try even harder than normal ALLOC_HARDER
3411 		 * users on the grounds that it's definitely going to be in
3412 		 * the exit path shortly and free memory. Any allocation it
3413 		 * makes during the free path will be small and short-lived.
3414 		 */
3415 		if (alloc_flags & ALLOC_OOM)
3416 			min -= min / 2;
3417 		else
3418 			min -= min / 4;
3419 	}
3420 
3421 
3422 #ifdef CONFIG_CMA
3423 	/* If allocation can't use CMA areas don't use free CMA pages */
3424 	if (!(alloc_flags & ALLOC_CMA))
3425 		free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
3426 #endif
3427 
3428 	/*
3429 	 * Check watermarks for an order-0 allocation request. If these
3430 	 * are not met, then a high-order request also cannot go ahead
3431 	 * even if a suitable page happened to be free.
3432 	 */
3433 	if (free_pages <= min + z->lowmem_reserve[classzone_idx])
3434 		return false;
3435 
3436 	/* If this is an order-0 request then the watermark is fine */
3437 	if (!order)
3438 		return true;
3439 
3440 	/* For a high-order request, check at least one suitable page is free */
3441 	for (o = order; o < MAX_ORDER; o++) {
3442 		struct free_area *area = &z->free_area[o];
3443 		int mt;
3444 
3445 		if (!area->nr_free)
3446 			continue;
3447 
3448 		for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
3449 			if (!free_area_empty(area, mt))
3450 				return true;
3451 		}
3452 
3453 #ifdef CONFIG_CMA
3454 		if ((alloc_flags & ALLOC_CMA) &&
3455 		    !free_area_empty(area, MIGRATE_CMA)) {
3456 			return true;
3457 		}
3458 #endif
3459 		if (alloc_harder &&
3460 			!list_empty(&area->free_list[MIGRATE_HIGHATOMIC]))
3461 			return true;
3462 	}
3463 	return false;
3464 }
3465 
3466 bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
3467 		      int classzone_idx, unsigned int alloc_flags)
3468 {
3469 	return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
3470 					zone_page_state(z, NR_FREE_PAGES));
3471 }
3472 
3473 static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
3474 		unsigned long mark, int classzone_idx, unsigned int alloc_flags)
3475 {
3476 	long free_pages = zone_page_state(z, NR_FREE_PAGES);
3477 	long cma_pages = 0;
3478 
3479 #ifdef CONFIG_CMA
3480 	/* If allocation can't use CMA areas don't use free CMA pages */
3481 	if (!(alloc_flags & ALLOC_CMA))
3482 		cma_pages = zone_page_state(z, NR_FREE_CMA_PAGES);
3483 #endif
3484 
3485 	/*
3486 	 * Fast check for order-0 only. If this fails then the reserves
3487 	 * need to be calculated. There is a corner case where the check
3488 	 * passes but only the high-order atomic reserve are free. If
3489 	 * the caller is !atomic then it'll uselessly search the free
3490 	 * list. That corner case is then slower but it is harmless.
3491 	 */
3492 	if (!order && (free_pages - cma_pages) > mark + z->lowmem_reserve[classzone_idx])
3493 		return true;
3494 
3495 	return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
3496 					free_pages);
3497 }
3498 
3499 bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
3500 			unsigned long mark, int classzone_idx)
3501 {
3502 	long free_pages = zone_page_state(z, NR_FREE_PAGES);
3503 
3504 	if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
3505 		free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
3506 
3507 	return __zone_watermark_ok(z, order, mark, classzone_idx, 0,
3508 								free_pages);
3509 }
3510 
3511 #ifdef CONFIG_NUMA
3512 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
3513 {
3514 	return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <=
3515 				node_reclaim_distance;
3516 }
3517 #else	/* CONFIG_NUMA */
3518 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
3519 {
3520 	return true;
3521 }
3522 #endif	/* CONFIG_NUMA */
3523 
3524 /*
3525  * The restriction on ZONE_DMA32 as being a suitable zone to use to avoid
3526  * fragmentation is subtle. If the preferred zone was HIGHMEM then
3527  * premature use of a lower zone may cause lowmem pressure problems that
3528  * are worse than fragmentation. If the next zone is ZONE_DMA then it is
3529  * probably too small. It only makes sense to spread allocations to avoid
3530  * fragmentation between the Normal and DMA32 zones.
3531  */
3532 static inline unsigned int
3533 alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
3534 {
3535 	unsigned int alloc_flags = 0;
3536 
3537 	if (gfp_mask & __GFP_KSWAPD_RECLAIM)
3538 		alloc_flags |= ALLOC_KSWAPD;
3539 
3540 #ifdef CONFIG_ZONE_DMA32
3541 	if (!zone)
3542 		return alloc_flags;
3543 
3544 	if (zone_idx(zone) != ZONE_NORMAL)
3545 		return alloc_flags;
3546 
3547 	/*
3548 	 * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and
3549 	 * the pointer is within zone->zone_pgdat->node_zones[]. Also assume
3550 	 * on UMA that if Normal is populated then so is DMA32.
3551 	 */
3552 	BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1);
3553 	if (nr_online_nodes > 1 && !populated_zone(--zone))
3554 		return alloc_flags;
3555 
3556 	alloc_flags |= ALLOC_NOFRAGMENT;
3557 #endif /* CONFIG_ZONE_DMA32 */
3558 	return alloc_flags;
3559 }
3560 
3561 /*
3562  * get_page_from_freelist goes through the zonelist trying to allocate
3563  * a page.
3564  */
3565 static struct page *
3566 get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
3567 						const struct alloc_context *ac)
3568 {
3569 	struct zoneref *z;
3570 	struct zone *zone;
3571 	struct pglist_data *last_pgdat_dirty_limit = NULL;
3572 	bool no_fallback;
3573 
3574 retry:
3575 	/*
3576 	 * Scan zonelist, looking for a zone with enough free.
3577 	 * See also __cpuset_node_allowed() comment in kernel/cpuset.c.
3578 	 */
3579 	no_fallback = alloc_flags & ALLOC_NOFRAGMENT;
3580 	z = ac->preferred_zoneref;
3581 	for_next_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
3582 								ac->nodemask) {
3583 		struct page *page;
3584 		unsigned long mark;
3585 
3586 		if (cpusets_enabled() &&
3587 			(alloc_flags & ALLOC_CPUSET) &&
3588 			!__cpuset_zone_allowed(zone, gfp_mask))
3589 				continue;
3590 		/*
3591 		 * When allocating a page cache page for writing, we
3592 		 * want to get it from a node that is within its dirty
3593 		 * limit, such that no single node holds more than its
3594 		 * proportional share of globally allowed dirty pages.
3595 		 * The dirty limits take into account the node's
3596 		 * lowmem reserves and high watermark so that kswapd
3597 		 * should be able to balance it without having to
3598 		 * write pages from its LRU list.
3599 		 *
3600 		 * XXX: For now, allow allocations to potentially
3601 		 * exceed the per-node dirty limit in the slowpath
3602 		 * (spread_dirty_pages unset) before going into reclaim,
3603 		 * which is important when on a NUMA setup the allowed
3604 		 * nodes are together not big enough to reach the
3605 		 * global limit.  The proper fix for these situations
3606 		 * will require awareness of nodes in the
3607 		 * dirty-throttling and the flusher threads.
3608 		 */
3609 		if (ac->spread_dirty_pages) {
3610 			if (last_pgdat_dirty_limit == zone->zone_pgdat)
3611 				continue;
3612 
3613 			if (!node_dirty_ok(zone->zone_pgdat)) {
3614 				last_pgdat_dirty_limit = zone->zone_pgdat;
3615 				continue;
3616 			}
3617 		}
3618 
3619 		if (no_fallback && nr_online_nodes > 1 &&
3620 		    zone != ac->preferred_zoneref->zone) {
3621 			int local_nid;
3622 
3623 			/*
3624 			 * If moving to a remote node, retry but allow
3625 			 * fragmenting fallbacks. Locality is more important
3626 			 * than fragmentation avoidance.
3627 			 */
3628 			local_nid = zone_to_nid(ac->preferred_zoneref->zone);
3629 			if (zone_to_nid(zone) != local_nid) {
3630 				alloc_flags &= ~ALLOC_NOFRAGMENT;
3631 				goto retry;
3632 			}
3633 		}
3634 
3635 		mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK);
3636 		if (!zone_watermark_fast(zone, order, mark,
3637 				       ac_classzone_idx(ac), alloc_flags)) {
3638 			int ret;
3639 
3640 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
3641 			/*
3642 			 * Watermark failed for this zone, but see if we can
3643 			 * grow this zone if it contains deferred pages.
3644 			 */
3645 			if (static_branch_unlikely(&deferred_pages)) {
3646 				if (_deferred_grow_zone(zone, order))
3647 					goto try_this_zone;
3648 			}
3649 #endif
3650 			/* Checked here to keep the fast path fast */
3651 			BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
3652 			if (alloc_flags & ALLOC_NO_WATERMARKS)
3653 				goto try_this_zone;
3654 
3655 			if (node_reclaim_mode == 0 ||
3656 			    !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
3657 				continue;
3658 
3659 			ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
3660 			switch (ret) {
3661 			case NODE_RECLAIM_NOSCAN:
3662 				/* did not scan */
3663 				continue;
3664 			case NODE_RECLAIM_FULL:
3665 				/* scanned but unreclaimable */
3666 				continue;
3667 			default:
3668 				/* did we reclaim enough */
3669 				if (zone_watermark_ok(zone, order, mark,
3670 						ac_classzone_idx(ac), alloc_flags))
3671 					goto try_this_zone;
3672 
3673 				continue;
3674 			}
3675 		}
3676 
3677 try_this_zone:
3678 		page = rmqueue(ac->preferred_zoneref->zone, zone, order,
3679 				gfp_mask, alloc_flags, ac->migratetype);
3680 		if (page) {
3681 			prep_new_page(page, order, gfp_mask, alloc_flags);
3682 
3683 			/*
3684 			 * If this is a high-order atomic allocation then check
3685 			 * if the pageblock should be reserved for the future
3686 			 */
3687 			if (unlikely(order && (alloc_flags & ALLOC_HARDER)))
3688 				reserve_highatomic_pageblock(page, zone, order);
3689 
3690 			return page;
3691 		} else {
3692 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
3693 			/* Try again if zone has deferred pages */
3694 			if (static_branch_unlikely(&deferred_pages)) {
3695 				if (_deferred_grow_zone(zone, order))
3696 					goto try_this_zone;
3697 			}
3698 #endif
3699 		}
3700 	}
3701 
3702 	/*
3703 	 * It's possible on a UMA machine to get through all zones that are
3704 	 * fragmented. If avoiding fragmentation, reset and try again.
3705 	 */
3706 	if (no_fallback) {
3707 		alloc_flags &= ~ALLOC_NOFRAGMENT;
3708 		goto retry;
3709 	}
3710 
3711 	return NULL;
3712 }
3713 
3714 static void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask)
3715 {
3716 	unsigned int filter = SHOW_MEM_FILTER_NODES;
3717 	static DEFINE_RATELIMIT_STATE(show_mem_rs, HZ, 1);
3718 
3719 	if (!__ratelimit(&show_mem_rs))
3720 		return;
3721 
3722 	/*
3723 	 * This documents exceptions given to allocations in certain
3724 	 * contexts that are allowed to allocate outside current's set
3725 	 * of allowed nodes.
3726 	 */
3727 	if (!(gfp_mask & __GFP_NOMEMALLOC))
3728 		if (tsk_is_oom_victim(current) ||
3729 		    (current->flags & (PF_MEMALLOC | PF_EXITING)))
3730 			filter &= ~SHOW_MEM_FILTER_NODES;
3731 	if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
3732 		filter &= ~SHOW_MEM_FILTER_NODES;
3733 
3734 	show_mem(filter, nodemask);
3735 }
3736 
3737 void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)
3738 {
3739 	struct va_format vaf;
3740 	va_list args;
3741 	static DEFINE_RATELIMIT_STATE(nopage_rs, DEFAULT_RATELIMIT_INTERVAL,
3742 				      DEFAULT_RATELIMIT_BURST);
3743 
3744 	if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs))
3745 		return;
3746 
3747 	va_start(args, fmt);
3748 	vaf.fmt = fmt;
3749 	vaf.va = &args;
3750 	pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl",
3751 			current->comm, &vaf, gfp_mask, &gfp_mask,
3752 			nodemask_pr_args(nodemask));
3753 	va_end(args);
3754 
3755 	cpuset_print_current_mems_allowed();
3756 	pr_cont("\n");
3757 	dump_stack();
3758 	warn_alloc_show_mem(gfp_mask, nodemask);
3759 }
3760 
3761 static inline struct page *
3762 __alloc_pages_cpuset_fallback(gfp_t gfp_mask, unsigned int order,
3763 			      unsigned int alloc_flags,
3764 			      const struct alloc_context *ac)
3765 {
3766 	struct page *page;
3767 
3768 	page = get_page_from_freelist(gfp_mask, order,
3769 			alloc_flags|ALLOC_CPUSET, ac);
3770 	/*
3771 	 * fallback to ignore cpuset restriction if our nodes
3772 	 * are depleted
3773 	 */
3774 	if (!page)
3775 		page = get_page_from_freelist(gfp_mask, order,
3776 				alloc_flags, ac);
3777 
3778 	return page;
3779 }
3780 
3781 static inline struct page *
3782 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
3783 	const struct alloc_context *ac, unsigned long *did_some_progress)
3784 {
3785 	struct oom_control oc = {
3786 		.zonelist = ac->zonelist,
3787 		.nodemask = ac->nodemask,
3788 		.memcg = NULL,
3789 		.gfp_mask = gfp_mask,
3790 		.order = order,
3791 	};
3792 	struct page *page;
3793 
3794 	*did_some_progress = 0;
3795 
3796 	/*
3797 	 * Acquire the oom lock.  If that fails, somebody else is
3798 	 * making progress for us.
3799 	 */
3800 	if (!mutex_trylock(&oom_lock)) {
3801 		*did_some_progress = 1;
3802 		schedule_timeout_uninterruptible(1);
3803 		return NULL;
3804 	}
3805 
3806 	/*
3807 	 * Go through the zonelist yet one more time, keep very high watermark
3808 	 * here, this is only to catch a parallel oom killing, we must fail if
3809 	 * we're still under heavy pressure. But make sure that this reclaim
3810 	 * attempt shall not depend on __GFP_DIRECT_RECLAIM && !__GFP_NORETRY
3811 	 * allocation which will never fail due to oom_lock already held.
3812 	 */
3813 	page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) &
3814 				      ~__GFP_DIRECT_RECLAIM, order,
3815 				      ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
3816 	if (page)
3817 		goto out;
3818 
3819 	/* Coredumps can quickly deplete all memory reserves */
3820 	if (current->flags & PF_DUMPCORE)
3821 		goto out;
3822 	/* The OOM killer will not help higher order allocs */
3823 	if (order > PAGE_ALLOC_COSTLY_ORDER)
3824 		goto out;
3825 	/*
3826 	 * We have already exhausted all our reclaim opportunities without any
3827 	 * success so it is time to admit defeat. We will skip the OOM killer
3828 	 * because it is very likely that the caller has a more reasonable
3829 	 * fallback than shooting a random task.
3830 	 */
3831 	if (gfp_mask & __GFP_RETRY_MAYFAIL)
3832 		goto out;
3833 	/* The OOM killer does not needlessly kill tasks for lowmem */
3834 	if (ac->high_zoneidx < ZONE_NORMAL)
3835 		goto out;
3836 	if (pm_suspended_storage())
3837 		goto out;
3838 	/*
3839 	 * XXX: GFP_NOFS allocations should rather fail than rely on
3840 	 * other request to make a forward progress.
3841 	 * We are in an unfortunate situation where out_of_memory cannot
3842 	 * do much for this context but let's try it to at least get
3843 	 * access to memory reserved if the current task is killed (see
3844 	 * out_of_memory). Once filesystems are ready to handle allocation
3845 	 * failures more gracefully we should just bail out here.
3846 	 */
3847 
3848 	/* The OOM killer may not free memory on a specific node */
3849 	if (gfp_mask & __GFP_THISNODE)
3850 		goto out;
3851 
3852 	/* Exhausted what can be done so it's blame time */
3853 	if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
3854 		*did_some_progress = 1;
3855 
3856 		/*
3857 		 * Help non-failing allocations by giving them access to memory
3858 		 * reserves
3859 		 */
3860 		if (gfp_mask & __GFP_NOFAIL)
3861 			page = __alloc_pages_cpuset_fallback(gfp_mask, order,
3862 					ALLOC_NO_WATERMARKS, ac);
3863 	}
3864 out:
3865 	mutex_unlock(&oom_lock);
3866 	return page;
3867 }
3868 
3869 /*
3870  * Maximum number of compaction retries wit a progress before OOM
3871  * killer is consider as the only way to move forward.
3872  */
3873 #define MAX_COMPACT_RETRIES 16
3874 
3875 #ifdef CONFIG_COMPACTION
3876 /* Try memory compaction for high-order allocations before reclaim */
3877 static struct page *
3878 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
3879 		unsigned int alloc_flags, const struct alloc_context *ac,
3880 		enum compact_priority prio, enum compact_result *compact_result)
3881 {
3882 	struct page *page = NULL;
3883 	unsigned long pflags;
3884 	unsigned int noreclaim_flag;
3885 
3886 	if (!order)
3887 		return NULL;
3888 
3889 	psi_memstall_enter(&pflags);
3890 	noreclaim_flag = memalloc_noreclaim_save();
3891 
3892 	*compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
3893 								prio, &page);
3894 
3895 	memalloc_noreclaim_restore(noreclaim_flag);
3896 	psi_memstall_leave(&pflags);
3897 
3898 	/*
3899 	 * At least in one zone compaction wasn't deferred or skipped, so let's
3900 	 * count a compaction stall
3901 	 */
3902 	count_vm_event(COMPACTSTALL);
3903 
3904 	/* Prep a captured page if available */
3905 	if (page)
3906 		prep_new_page(page, order, gfp_mask, alloc_flags);
3907 
3908 	/* Try get a page from the freelist if available */
3909 	if (!page)
3910 		page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3911 
3912 	if (page) {
3913 		struct zone *zone = page_zone(page);
3914 
3915 		zone->compact_blockskip_flush = false;
3916 		compaction_defer_reset(zone, order, true);
3917 		count_vm_event(COMPACTSUCCESS);
3918 		return page;
3919 	}
3920 
3921 	/*
3922 	 * It's bad if compaction run occurs and fails. The most likely reason
3923 	 * is that pages exist, but not enough to satisfy watermarks.
3924 	 */
3925 	count_vm_event(COMPACTFAIL);
3926 
3927 	cond_resched();
3928 
3929 	return NULL;
3930 }
3931 
3932 static inline bool
3933 should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
3934 		     enum compact_result compact_result,
3935 		     enum compact_priority *compact_priority,
3936 		     int *compaction_retries)
3937 {
3938 	int max_retries = MAX_COMPACT_RETRIES;
3939 	int min_priority;
3940 	bool ret = false;
3941 	int retries = *compaction_retries;
3942 	enum compact_priority priority = *compact_priority;
3943 
3944 	if (!order)
3945 		return false;
3946 
3947 	if (compaction_made_progress(compact_result))
3948 		(*compaction_retries)++;
3949 
3950 	/*
3951 	 * compaction considers all the zone as desperately out of memory
3952 	 * so it doesn't really make much sense to retry except when the
3953 	 * failure could be caused by insufficient priority
3954 	 */
3955 	if (compaction_failed(compact_result))
3956 		goto check_priority;
3957 
3958 	/*
3959 	 * compaction was skipped because there are not enough order-0 pages
3960 	 * to work with, so we retry only if it looks like reclaim can help.
3961 	 */
3962 	if (compaction_needs_reclaim(compact_result)) {
3963 		ret = compaction_zonelist_suitable(ac, order, alloc_flags);
3964 		goto out;
3965 	}
3966 
3967 	/*
3968 	 * make sure the compaction wasn't deferred or didn't bail out early
3969 	 * due to locks contention before we declare that we should give up.
3970 	 * But the next retry should use a higher priority if allowed, so
3971 	 * we don't just keep bailing out endlessly.
3972 	 */
3973 	if (compaction_withdrawn(compact_result)) {
3974 		goto check_priority;
3975 	}
3976 
3977 	/*
3978 	 * !costly requests are much more important than __GFP_RETRY_MAYFAIL
3979 	 * costly ones because they are de facto nofail and invoke OOM
3980 	 * killer to move on while costly can fail and users are ready
3981 	 * to cope with that. 1/4 retries is rather arbitrary but we
3982 	 * would need much more detailed feedback from compaction to
3983 	 * make a better decision.
3984 	 */
3985 	if (order > PAGE_ALLOC_COSTLY_ORDER)
3986 		max_retries /= 4;
3987 	if (*compaction_retries <= max_retries) {
3988 		ret = true;
3989 		goto out;
3990 	}
3991 
3992 	/*
3993 	 * Make sure there are attempts at the highest priority if we exhausted
3994 	 * all retries or failed at the lower priorities.
3995 	 */
3996 check_priority:
3997 	min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ?
3998 			MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;
3999 
4000 	if (*compact_priority > min_priority) {
4001 		(*compact_priority)--;
4002 		*compaction_retries = 0;
4003 		ret = true;
4004 	}
4005 out:
4006 	trace_compact_retry(order, priority, compact_result, retries, max_retries, ret);
4007 	return ret;
4008 }
4009 #else
4010 static inline struct page *
4011 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
4012 		unsigned int alloc_flags, const struct alloc_context *ac,
4013 		enum compact_priority prio, enum compact_result *compact_result)
4014 {
4015 	*compact_result = COMPACT_SKIPPED;
4016 	return NULL;
4017 }
4018 
4019 static inline bool
4020 should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
4021 		     enum compact_result compact_result,
4022 		     enum compact_priority *compact_priority,
4023 		     int *compaction_retries)
4024 {
4025 	struct zone *zone;
4026 	struct zoneref *z;
4027 
4028 	if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
4029 		return false;
4030 
4031 	/*
4032 	 * There are setups with compaction disabled which would prefer to loop
4033 	 * inside the allocator rather than hit the oom killer prematurely.
4034 	 * Let's give them a good hope and keep retrying while the order-0
4035 	 * watermarks are OK.
4036 	 */
4037 	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
4038 					ac->nodemask) {
4039 		if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
4040 					ac_classzone_idx(ac), alloc_flags))
4041 			return true;
4042 	}
4043 	return false;
4044 }
4045 #endif /* CONFIG_COMPACTION */
4046 
4047 #ifdef CONFIG_LOCKDEP
4048 static struct lockdep_map __fs_reclaim_map =
4049 	STATIC_LOCKDEP_MAP_INIT("fs_reclaim", &__fs_reclaim_map);
4050 
4051 static bool __need_fs_reclaim(gfp_t gfp_mask)
4052 {
4053 	gfp_mask = current_gfp_context(gfp_mask);
4054 
4055 	/* no reclaim without waiting on it */
4056 	if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
4057 		return false;
4058 
4059 	/* this guy won't enter reclaim */
4060 	if (current->flags & PF_MEMALLOC)
4061 		return false;
4062 
4063 	/* We're only interested __GFP_FS allocations for now */
4064 	if (!(gfp_mask & __GFP_FS))
4065 		return false;
4066 
4067 	if (gfp_mask & __GFP_NOLOCKDEP)
4068 		return false;
4069 
4070 	return true;
4071 }
4072 
4073 void __fs_reclaim_acquire(void)
4074 {
4075 	lock_map_acquire(&__fs_reclaim_map);
4076 }
4077 
4078 void __fs_reclaim_release(void)
4079 {
4080 	lock_map_release(&__fs_reclaim_map);
4081 }
4082 
4083 void fs_reclaim_acquire(gfp_t gfp_mask)
4084 {
4085 	if (__need_fs_reclaim(gfp_mask))
4086 		__fs_reclaim_acquire();
4087 }
4088 EXPORT_SYMBOL_GPL(fs_reclaim_acquire);
4089 
4090 void fs_reclaim_release(gfp_t gfp_mask)
4091 {
4092 	if (__need_fs_reclaim(gfp_mask))
4093 		__fs_reclaim_release();
4094 }
4095 EXPORT_SYMBOL_GPL(fs_reclaim_release);
4096 #endif
4097 
4098 /* Perform direct synchronous page reclaim */
4099 static int
4100 __perform_reclaim(gfp_t gfp_mask, unsigned int order,
4101 					const struct alloc_context *ac)
4102 {
4103 	int progress;
4104 	unsigned int noreclaim_flag;
4105 	unsigned long pflags;
4106 
4107 	cond_resched();
4108 
4109 	/* We now go into synchronous reclaim */
4110 	cpuset_memory_pressure_bump();
4111 	psi_memstall_enter(&pflags);
4112 	fs_reclaim_acquire(gfp_mask);
4113 	noreclaim_flag = memalloc_noreclaim_save();
4114 
4115 	progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
4116 								ac->nodemask);
4117 
4118 	memalloc_noreclaim_restore(noreclaim_flag);
4119 	fs_reclaim_release(gfp_mask);
4120 	psi_memstall_leave(&pflags);
4121 
4122 	cond_resched();
4123 
4124 	return progress;
4125 }
4126 
4127 /* The really slow allocator path where we enter direct reclaim */
4128 static inline struct page *
4129 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
4130 		unsigned int alloc_flags, const struct alloc_context *ac,
4131 		unsigned long *did_some_progress)
4132 {
4133 	struct page *page = NULL;
4134 	bool drained = false;
4135 
4136 	*did_some_progress = __perform_reclaim(gfp_mask, order, ac);
4137 	if (unlikely(!(*did_some_progress)))
4138 		return NULL;
4139 
4140 retry:
4141 	page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4142 
4143 	/*
4144 	 * If an allocation failed after direct reclaim, it could be because
4145 	 * pages are pinned on the per-cpu lists or in high alloc reserves.
4146 	 * Shrink them them and try again
4147 	 */
4148 	if (!page && !drained) {
4149 		unreserve_highatomic_pageblock(ac, false);
4150 		drain_all_pages(NULL);
4151 		drained = true;
4152 		goto retry;
4153 	}
4154 
4155 	return page;
4156 }
4157 
4158 static void wake_all_kswapds(unsigned int order, gfp_t gfp_mask,
4159 			     const struct alloc_context *ac)
4160 {
4161 	struct zoneref *z;
4162 	struct zone *zone;
4163 	pg_data_t *last_pgdat = NULL;
4164 	enum zone_type high_zoneidx = ac->high_zoneidx;
4165 
4166 	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, high_zoneidx,
4167 					ac->nodemask) {
4168 		if (last_pgdat != zone->zone_pgdat)
4169 			wakeup_kswapd(zone, gfp_mask, order, high_zoneidx);
4170 		last_pgdat = zone->zone_pgdat;
4171 	}
4172 }
4173 
4174 static inline unsigned int
4175 gfp_to_alloc_flags(gfp_t gfp_mask)
4176 {
4177 	unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
4178 
4179 	/* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
4180 	BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
4181 
4182 	/*
4183 	 * The caller may dip into page reserves a bit more if the caller
4184 	 * cannot run direct reclaim, or if the caller has realtime scheduling
4185 	 * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
4186 	 * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
4187 	 */
4188 	alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
4189 
4190 	if (gfp_mask & __GFP_ATOMIC) {
4191 		/*
4192 		 * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
4193 		 * if it can't schedule.
4194 		 */
4195 		if (!(gfp_mask & __GFP_NOMEMALLOC))
4196 			alloc_flags |= ALLOC_HARDER;
4197 		/*
4198 		 * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
4199 		 * comment for __cpuset_node_allowed().
4200 		 */
4201 		alloc_flags &= ~ALLOC_CPUSET;
4202 	} else if (unlikely(rt_task(current)) && !in_interrupt())
4203 		alloc_flags |= ALLOC_HARDER;
4204 
4205 	if (gfp_mask & __GFP_KSWAPD_RECLAIM)
4206 		alloc_flags |= ALLOC_KSWAPD;
4207 
4208 #ifdef CONFIG_CMA
4209 	if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
4210 		alloc_flags |= ALLOC_CMA;
4211 #endif
4212 	return alloc_flags;
4213 }
4214 
4215 static bool oom_reserves_allowed(struct task_struct *tsk)
4216 {
4217 	if (!tsk_is_oom_victim(tsk))
4218 		return false;
4219 
4220 	/*
4221 	 * !MMU doesn't have oom reaper so give access to memory reserves
4222 	 * only to the thread with TIF_MEMDIE set
4223 	 */
4224 	if (!IS_ENABLED(CONFIG_MMU) && !test_thread_flag(TIF_MEMDIE))
4225 		return false;
4226 
4227 	return true;
4228 }
4229 
4230 /*
4231  * Distinguish requests which really need access to full memory
4232  * reserves from oom victims which can live with a portion of it
4233  */
4234 static inline int __gfp_pfmemalloc_flags(gfp_t gfp_mask)
4235 {
4236 	if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
4237 		return 0;
4238 	if (gfp_mask & __GFP_MEMALLOC)
4239 		return ALLOC_NO_WATERMARKS;
4240 	if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
4241 		return ALLOC_NO_WATERMARKS;
4242 	if (!in_interrupt()) {
4243 		if (current->flags & PF_MEMALLOC)
4244 			return ALLOC_NO_WATERMARKS;
4245 		else if (oom_reserves_allowed(current))
4246 			return ALLOC_OOM;
4247 	}
4248 
4249 	return 0;
4250 }
4251 
4252 bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
4253 {
4254 	return !!__gfp_pfmemalloc_flags(gfp_mask);
4255 }
4256 
4257 /*
4258  * Checks whether it makes sense to retry the reclaim to make a forward progress
4259  * for the given allocation request.
4260  *
4261  * We give up when we either have tried MAX_RECLAIM_RETRIES in a row
4262  * without success, or when we couldn't even meet the watermark if we
4263  * reclaimed all remaining pages on the LRU lists.
4264  *
4265  * Returns true if a retry is viable or false to enter the oom path.
4266  */
4267 static inline bool
4268 should_reclaim_retry(gfp_t gfp_mask, unsigned order,
4269 		     struct alloc_context *ac, int alloc_flags,
4270 		     bool did_some_progress, int *no_progress_loops)
4271 {
4272 	struct zone *zone;
4273 	struct zoneref *z;
4274 	bool ret = false;
4275 
4276 	/*
4277 	 * Costly allocations might have made a progress but this doesn't mean
4278 	 * their order will become available due to high fragmentation so
4279 	 * always increment the no progress counter for them
4280 	 */
4281 	if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
4282 		*no_progress_loops = 0;
4283 	else
4284 		(*no_progress_loops)++;
4285 
4286 	/*
4287 	 * Make sure we converge to OOM if we cannot make any progress
4288 	 * several times in the row.
4289 	 */
4290 	if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
4291 		/* Before OOM, exhaust highatomic_reserve */
4292 		return unreserve_highatomic_pageblock(ac, true);
4293 	}
4294 
4295 	/*
4296 	 * Keep reclaiming pages while there is a chance this will lead
4297 	 * somewhere.  If none of the target zones can satisfy our allocation
4298 	 * request even if all reclaimable pages are considered then we are
4299 	 * screwed and have to go OOM.
4300 	 */
4301 	for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
4302 					ac->nodemask) {
4303 		unsigned long available;
4304 		unsigned long reclaimable;
4305 		unsigned long min_wmark = min_wmark_pages(zone);
4306 		bool wmark;
4307 
4308 		available = reclaimable = zone_reclaimable_pages(zone);
4309 		available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
4310 
4311 		/*
4312 		 * Would the allocation succeed if we reclaimed all
4313 		 * reclaimable pages?
4314 		 */
4315 		wmark = __zone_watermark_ok(zone, order, min_wmark,
4316 				ac_classzone_idx(ac), alloc_flags, available);
4317 		trace_reclaim_retry_zone(z, order, reclaimable,
4318 				available, min_wmark, *no_progress_loops, wmark);
4319 		if (wmark) {
4320 			/*
4321 			 * If we didn't make any progress and have a lot of
4322 			 * dirty + writeback pages then we should wait for
4323 			 * an IO to complete to slow down the reclaim and
4324 			 * prevent from pre mature OOM
4325 			 */
4326 			if (!did_some_progress) {
4327 				unsigned long write_pending;
4328 
4329 				write_pending = zone_page_state_snapshot(zone,
4330 							NR_ZONE_WRITE_PENDING);
4331 
4332 				if (2 * write_pending > reclaimable) {
4333 					congestion_wait(BLK_RW_ASYNC, HZ/10);
4334 					return true;
4335 				}
4336 			}
4337 
4338 			ret = true;
4339 			goto out;
4340 		}
4341 	}
4342 
4343 out:
4344 	/*
4345 	 * Memory allocation/reclaim might be called from a WQ context and the
4346 	 * current implementation of the WQ concurrency control doesn't
4347 	 * recognize that a particular WQ is congested if the worker thread is
4348 	 * looping without ever sleeping. Therefore we have to do a short sleep
4349 	 * here rather than calling cond_resched().
4350 	 */
4351 	if (current->flags & PF_WQ_WORKER)
4352 		schedule_timeout_uninterruptible(1);
4353 	else
4354 		cond_resched();
4355 	return ret;
4356 }
4357 
4358 static inline bool
4359 check_retry_cpuset(int cpuset_mems_cookie, struct alloc_context *ac)
4360 {
4361 	/*
4362 	 * It's possible that cpuset's mems_allowed and the nodemask from
4363 	 * mempolicy don't intersect. This should be normally dealt with by
4364 	 * policy_nodemask(), but it's possible to race with cpuset update in
4365 	 * such a way the check therein was true, and then it became false
4366 	 * before we got our cpuset_mems_cookie here.
4367 	 * This assumes that for all allocations, ac->nodemask can come only
4368 	 * from MPOL_BIND mempolicy (whose documented semantics is to be ignored
4369 	 * when it does not intersect with the cpuset restrictions) or the
4370 	 * caller can deal with a violated nodemask.
4371 	 */
4372 	if (cpusets_enabled() && ac->nodemask &&
4373 			!cpuset_nodemask_valid_mems_allowed(ac->nodemask)) {
4374 		ac->nodemask = NULL;
4375 		return true;
4376 	}
4377 
4378 	/*
4379 	 * When updating a task's mems_allowed or mempolicy nodemask, it is
4380 	 * possible to race with parallel threads in such a way that our
4381 	 * allocation can fail while the mask is being updated. If we are about
4382 	 * to fail, check if the cpuset changed during allocation and if so,
4383 	 * retry.
4384 	 */
4385 	if (read_mems_allowed_retry(cpuset_mems_cookie))
4386 		return true;
4387 
4388 	return false;
4389 }
4390 
4391 static inline struct page *
4392 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
4393 						struct alloc_context *ac)
4394 {
4395 	bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
4396 	const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER;
4397 	struct page *page = NULL;
4398 	unsigned int alloc_flags;
4399 	unsigned long did_some_progress;
4400 	enum compact_priority compact_priority;
4401 	enum compact_result compact_result;
4402 	int compaction_retries;
4403 	int no_progress_loops;
4404 	unsigned int cpuset_mems_cookie;
4405 	int reserve_flags;
4406 
4407 	/*
4408 	 * We also sanity check to catch abuse of atomic reserves being used by
4409 	 * callers that are not in atomic context.
4410 	 */
4411 	if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) ==
4412 				(__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
4413 		gfp_mask &= ~__GFP_ATOMIC;
4414 
4415 retry_cpuset:
4416 	compaction_retries = 0;
4417 	no_progress_loops = 0;
4418 	compact_priority = DEF_COMPACT_PRIORITY;
4419 	cpuset_mems_cookie = read_mems_allowed_begin();
4420 
4421 	/*
4422 	 * The fast path uses conservative alloc_flags to succeed only until
4423 	 * kswapd needs to be woken up, and to avoid the cost of setting up
4424 	 * alloc_flags precisely. So we do that now.
4425 	 */
4426 	alloc_flags = gfp_to_alloc_flags(gfp_mask);
4427 
4428 	/*
4429 	 * We need to recalculate the starting point for the zonelist iterator
4430 	 * because we might have used different nodemask in the fast path, or
4431 	 * there was a cpuset modification and we are retrying - otherwise we
4432 	 * could end up iterating over non-eligible zones endlessly.
4433 	 */
4434 	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4435 					ac->high_zoneidx, ac->nodemask);
4436 	if (!ac->preferred_zoneref->zone)
4437 		goto nopage;
4438 
4439 	if (alloc_flags & ALLOC_KSWAPD)
4440 		wake_all_kswapds(order, gfp_mask, ac);
4441 
4442 	/*
4443 	 * The adjusted alloc_flags might result in immediate success, so try
4444 	 * that first
4445 	 */
4446 	page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4447 	if (page)
4448 		goto got_pg;
4449 
4450 	/*
4451 	 * For costly allocations, try direct compaction first, as it's likely
4452 	 * that we have enough base pages and don't need to reclaim. For non-
4453 	 * movable high-order allocations, do that as well, as compaction will
4454 	 * try prevent permanent fragmentation by migrating from blocks of the
4455 	 * same migratetype.
4456 	 * Don't try this for allocations that are allowed to ignore
4457 	 * watermarks, as the ALLOC_NO_WATERMARKS attempt didn't yet happen.
4458 	 */
4459 	if (can_direct_reclaim &&
4460 			(costly_order ||
4461 			   (order > 0 && ac->migratetype != MIGRATE_MOVABLE))
4462 			&& !gfp_pfmemalloc_allowed(gfp_mask)) {
4463 		page = __alloc_pages_direct_compact(gfp_mask, order,
4464 						alloc_flags, ac,
4465 						INIT_COMPACT_PRIORITY,
4466 						&compact_result);
4467 		if (page)
4468 			goto got_pg;
4469 
4470 		/*
4471 		 * Checks for costly allocations with __GFP_NORETRY, which
4472 		 * includes THP page fault allocations
4473 		 */
4474 		if (costly_order && (gfp_mask & __GFP_NORETRY)) {
4475 			/*
4476 			 * If compaction is deferred for high-order allocations,
4477 			 * it is because sync compaction recently failed. If
4478 			 * this is the case and the caller requested a THP
4479 			 * allocation, we do not want to heavily disrupt the
4480 			 * system, so we fail the allocation instead of entering
4481 			 * direct reclaim.
4482 			 */
4483 			if (compact_result == COMPACT_DEFERRED)
4484 				goto nopage;
4485 
4486 			/*
4487 			 * Looks like reclaim/compaction is worth trying, but
4488 			 * sync compaction could be very expensive, so keep
4489 			 * using async compaction.
4490 			 */
4491 			compact_priority = INIT_COMPACT_PRIORITY;
4492 		}
4493 	}
4494 
4495 retry:
4496 	/* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
4497 	if (alloc_flags & ALLOC_KSWAPD)
4498 		wake_all_kswapds(order, gfp_mask, ac);
4499 
4500 	reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
4501 	if (reserve_flags)
4502 		alloc_flags = reserve_flags;
4503 
4504 	/*
4505 	 * Reset the nodemask and zonelist iterators if memory policies can be
4506 	 * ignored. These allocations are high priority and system rather than
4507 	 * user oriented.
4508 	 */
4509 	if (!(alloc_flags & ALLOC_CPUSET) || reserve_flags) {
4510 		ac->nodemask = NULL;
4511 		ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4512 					ac->high_zoneidx, ac->nodemask);
4513 	}
4514 
4515 	/* Attempt with potentially adjusted zonelist and alloc_flags */
4516 	page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
4517 	if (page)
4518 		goto got_pg;
4519 
4520 	/* Caller is not willing to reclaim, we can't balance anything */
4521 	if (!can_direct_reclaim)
4522 		goto nopage;
4523 
4524 	/* Avoid recursion of direct reclaim */
4525 	if (current->flags & PF_MEMALLOC)
4526 		goto nopage;
4527 
4528 	/* Try direct reclaim and then allocating */
4529 	page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
4530 							&did_some_progress);
4531 	if (page)
4532 		goto got_pg;
4533 
4534 	/* Try direct compaction and then allocating */
4535 	page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
4536 					compact_priority, &compact_result);
4537 	if (page)
4538 		goto got_pg;
4539 
4540 	/* Do not loop if specifically requested */
4541 	if (gfp_mask & __GFP_NORETRY)
4542 		goto nopage;
4543 
4544 	/*
4545 	 * Do not retry costly high order allocations unless they are
4546 	 * __GFP_RETRY_MAYFAIL
4547 	 */
4548 	if (costly_order && !(gfp_mask & __GFP_RETRY_MAYFAIL))
4549 		goto nopage;
4550 
4551 	if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
4552 				 did_some_progress > 0, &no_progress_loops))
4553 		goto retry;
4554 
4555 	/*
4556 	 * It doesn't make any sense to retry for the compaction if the order-0
4557 	 * reclaim is not able to make any progress because the current
4558 	 * implementation of the compaction depends on the sufficient amount
4559 	 * of free memory (see __compaction_suitable)
4560 	 */
4561 	if (did_some_progress > 0 &&
4562 			should_compact_retry(ac, order, alloc_flags,
4563 				compact_result, &compact_priority,
4564 				&compaction_retries))
4565 		goto retry;
4566 
4567 
4568 	/* Deal with possible cpuset update races before we start OOM killing */
4569 	if (check_retry_cpuset(cpuset_mems_cookie, ac))
4570 		goto retry_cpuset;
4571 
4572 	/* Reclaim has failed us, start killing things */
4573 	page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
4574 	if (page)
4575 		goto got_pg;
4576 
4577 	/* Avoid allocations with no watermarks from looping endlessly */
4578 	if (tsk_is_oom_victim(current) &&
4579 	    (alloc_flags == ALLOC_OOM ||
4580 	     (gfp_mask & __GFP_NOMEMALLOC)))
4581 		goto nopage;
4582 
4583 	/* Retry as long as the OOM killer is making progress */
4584 	if (did_some_progress) {
4585 		no_progress_loops = 0;
4586 		goto retry;
4587 	}
4588 
4589 nopage:
4590 	/* Deal with possible cpuset update races before we fail */
4591 	if (check_retry_cpuset(cpuset_mems_cookie, ac))
4592 		goto retry_cpuset;
4593 
4594 	/*
4595 	 * Make sure that __GFP_NOFAIL request doesn't leak out and make sure
4596 	 * we always retry
4597 	 */
4598 	if (gfp_mask & __GFP_NOFAIL) {
4599 		/*
4600 		 * All existing users of the __GFP_NOFAIL are blockable, so warn
4601 		 * of any new users that actually require GFP_NOWAIT
4602 		 */
4603 		if (WARN_ON_ONCE(!can_direct_reclaim))
4604 			goto fail;
4605 
4606 		/*
4607 		 * PF_MEMALLOC request from this context is rather bizarre
4608 		 * because we cannot reclaim anything and only can loop waiting
4609 		 * for somebody to do a work for us
4610 		 */
4611 		WARN_ON_ONCE(current->flags & PF_MEMALLOC);
4612 
4613 		/*
4614 		 * non failing costly orders are a hard requirement which we
4615 		 * are not prepared for much so let's warn about these users
4616 		 * so that we can identify them and convert them to something
4617 		 * else.
4618 		 */
4619 		WARN_ON_ONCE(order > PAGE_ALLOC_COSTLY_ORDER);
4620 
4621 		/*
4622 		 * Help non-failing allocations by giving them access to memory
4623 		 * reserves but do not use ALLOC_NO_WATERMARKS because this
4624 		 * could deplete whole memory reserves which would just make
4625 		 * the situation worse
4626 		 */
4627 		page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_HARDER, ac);
4628 		if (page)
4629 			goto got_pg;
4630 
4631 		cond_resched();
4632 		goto retry;
4633 	}
4634 fail:
4635 	warn_alloc(gfp_mask, ac->nodemask,
4636 			"page allocation failure: order:%u", order);
4637 got_pg:
4638 	return page;
4639 }
4640 
4641 static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
4642 		int preferred_nid, nodemask_t *nodemask,
4643 		struct alloc_context *ac, gfp_t *alloc_mask,
4644 		unsigned int *alloc_flags)
4645 {
4646 	ac->high_zoneidx = gfp_zone(gfp_mask);
4647 	ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
4648 	ac->nodemask = nodemask;
4649 	ac->migratetype = gfpflags_to_migratetype(gfp_mask);
4650 
4651 	if (cpusets_enabled()) {
4652 		*alloc_mask |= __GFP_HARDWALL;
4653 		if (!ac->nodemask)
4654 			ac->nodemask = &cpuset_current_mems_allowed;
4655 		else
4656 			*alloc_flags |= ALLOC_CPUSET;
4657 	}
4658 
4659 	fs_reclaim_acquire(gfp_mask);
4660 	fs_reclaim_release(gfp_mask);
4661 
4662 	might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
4663 
4664 	if (should_fail_alloc_page(gfp_mask, order))
4665 		return false;
4666 
4667 	if (IS_ENABLED(CONFIG_CMA) && ac->migratetype == MIGRATE_MOVABLE)
4668 		*alloc_flags |= ALLOC_CMA;
4669 
4670 	return true;
4671 }
4672 
4673 /* Determine whether to spread dirty pages and what the first usable zone */
4674 static inline void finalise_ac(gfp_t gfp_mask, struct alloc_context *ac)
4675 {
4676 	/* Dirty zone balancing only done in the fast path */
4677 	ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);
4678 
4679 	/*
4680 	 * The preferred zone is used for statistics but crucially it is
4681 	 * also used as the starting point for the zonelist iterator. It
4682 	 * may get reset for allocations that ignore memory policies.
4683 	 */
4684 	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
4685 					ac->high_zoneidx, ac->nodemask);
4686 }
4687 
4688 /*
4689  * This is the 'heart' of the zoned buddy allocator.
4690  */
4691 struct page *
4692 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
4693 							nodemask_t *nodemask)
4694 {
4695 	struct page *page;
4696 	unsigned int alloc_flags = ALLOC_WMARK_LOW;
4697 	gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */
4698 	struct alloc_context ac = { };
4699 
4700 	/*
4701 	 * There are several places where we assume that the order value is sane
4702 	 * so bail out early if the request is out of bound.
4703 	 */
4704 	if (unlikely(order >= MAX_ORDER)) {
4705 		WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
4706 		return NULL;
4707 	}
4708 
4709 	gfp_mask &= gfp_allowed_mask;
4710 	alloc_mask = gfp_mask;
4711 	if (!prepare_alloc_pages(gfp_mask, order, preferred_nid, nodemask, &ac, &alloc_mask, &alloc_flags))
4712 		return NULL;
4713 
4714 	finalise_ac(gfp_mask, &ac);
4715 
4716 	/*
4717 	 * Forbid the first pass from falling back to types that fragment
4718 	 * memory until all local zones are considered.
4719 	 */
4720 	alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp_mask);
4721 
4722 	/* First allocation attempt */
4723 	page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
4724 	if (likely(page))
4725 		goto out;
4726 
4727 	/*
4728 	 * Apply scoped allocation constraints. This is mainly about GFP_NOFS
4729 	 * resp. GFP_NOIO which has to be inherited for all allocation requests
4730 	 * from a particular context which has been marked by
4731 	 * memalloc_no{fs,io}_{save,restore}.
4732 	 */
4733 	alloc_mask = current_gfp_context(gfp_mask);
4734 	ac.spread_dirty_pages = false;
4735 
4736 	/*
4737 	 * Restore the original nodemask if it was potentially replaced with
4738 	 * &cpuset_current_mems_allowed to optimize the fast-path attempt.
4739 	 */
4740 	if (unlikely(ac.nodemask != nodemask))
4741 		ac.nodemask = nodemask;
4742 
4743 	page = __alloc_pages_slowpath(alloc_mask, order, &ac);
4744 
4745 out:
4746 	if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
4747 	    unlikely(__memcg_kmem_charge(page, gfp_mask, order) != 0)) {
4748 		__free_pages(page, order);
4749 		page = NULL;
4750 	}
4751 
4752 	trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);
4753 
4754 	return page;
4755 }
4756 EXPORT_SYMBOL(__alloc_pages_nodemask);
4757 
4758 /*
4759  * Common helper functions. Never use with __GFP_HIGHMEM because the returned
4760  * address cannot represent highmem pages. Use alloc_pages and then kmap if
4761  * you need to access high mem.
4762  */
4763 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
4764 {
4765 	struct page *page;
4766 
4767 	page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, order);
4768 	if (!page)
4769 		return 0;
4770 	return (unsigned long) page_address(page);
4771 }
4772 EXPORT_SYMBOL(__get_free_pages);
4773 
4774 unsigned long get_zeroed_page(gfp_t gfp_mask)
4775 {
4776 	return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
4777 }
4778 EXPORT_SYMBOL(get_zeroed_page);
4779 
4780 static inline void free_the_page(struct page *page, unsigned int order)
4781 {
4782 	if (order == 0)		/* Via pcp? */
4783 		free_unref_page(page);
4784 	else
4785 		__free_pages_ok(page, order);
4786 }
4787 
4788 void __free_pages(struct page *page, unsigned int order)
4789 {
4790 	if (put_page_testzero(page))
4791 		free_the_page(page, order);
4792 }
4793 EXPORT_SYMBOL(__free_pages);
4794 
4795 void free_pages(unsigned long addr, unsigned int order)
4796 {
4797 	if (addr != 0) {
4798 		VM_BUG_ON(!virt_addr_valid((void *)addr));
4799 		__free_pages(virt_to_page((void *)addr), order);
4800 	}
4801 }
4802 
4803 EXPORT_SYMBOL(free_pages);
4804 
4805 /*
4806  * Page Fragment:
4807  *  An arbitrary-length arbitrary-offset area of memory which resides
4808  *  within a 0 or higher order page.  Multiple fragments within that page
4809  *  are individually refcounted, in the page's reference counter.
4810  *
4811  * The page_frag functions below provide a simple allocation framework for
4812  * page fragments.  This is used by the network stack and network device
4813  * drivers to provide a backing region of memory for use as either an
4814  * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
4815  */
4816 static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
4817 					     gfp_t gfp_mask)
4818 {
4819 	struct page *page = NULL;
4820 	gfp_t gfp = gfp_mask;
4821 
4822 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4823 	gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
4824 		    __GFP_NOMEMALLOC;
4825 	page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
4826 				PAGE_FRAG_CACHE_MAX_ORDER);
4827 	nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
4828 #endif
4829 	if (unlikely(!page))
4830 		page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
4831 
4832 	nc->va = page ? page_address(page) : NULL;
4833 
4834 	return page;
4835 }
4836 
4837 void __page_frag_cache_drain(struct page *page, unsigned int count)
4838 {
4839 	VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
4840 
4841 	if (page_ref_sub_and_test(page, count))
4842 		free_the_page(page, compound_order(page));
4843 }
4844 EXPORT_SYMBOL(__page_frag_cache_drain);
4845 
4846 void *page_frag_alloc(struct page_frag_cache *nc,
4847 		      unsigned int fragsz, gfp_t gfp_mask)
4848 {
4849 	unsigned int size = PAGE_SIZE;
4850 	struct page *page;
4851 	int offset;
4852 
4853 	if (unlikely(!nc->va)) {
4854 refill:
4855 		page = __page_frag_cache_refill(nc, gfp_mask);
4856 		if (!page)
4857 			return NULL;
4858 
4859 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4860 		/* if size can vary use size else just use PAGE_SIZE */
4861 		size = nc->size;
4862 #endif
4863 		/* Even if we own the page, we do not use atomic_set().
4864 		 * This would break get_page_unless_zero() users.
4865 		 */
4866 		page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE);
4867 
4868 		/* reset page count bias and offset to start of new frag */
4869 		nc->pfmemalloc = page_is_pfmemalloc(page);
4870 		nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
4871 		nc->offset = size;
4872 	}
4873 
4874 	offset = nc->offset - fragsz;
4875 	if (unlikely(offset < 0)) {
4876 		page = virt_to_page(nc->va);
4877 
4878 		if (!page_ref_sub_and_test(page, nc->pagecnt_bias))
4879 			goto refill;
4880 
4881 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
4882 		/* if size can vary use size else just use PAGE_SIZE */
4883 		size = nc->size;
4884 #endif
4885 		/* OK, page count is 0, we can safely set it */
4886 		set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1);
4887 
4888 		/* reset page count bias and offset to start of new frag */
4889 		nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
4890 		offset = size - fragsz;
4891 	}
4892 
4893 	nc->pagecnt_bias--;
4894 	nc->offset = offset;
4895 
4896 	return nc->va + offset;
4897 }
4898 EXPORT_SYMBOL(page_frag_alloc);
4899 
4900 /*
4901  * Frees a page fragment allocated out of either a compound or order 0 page.
4902  */
4903 void page_frag_free(void *addr)
4904 {
4905 	struct page *page = virt_to_head_page(addr);
4906 
4907 	if (unlikely(put_page_testzero(page)))
4908 		free_the_page(page, compound_order(page));
4909 }
4910 EXPORT_SYMBOL(page_frag_free);
4911 
4912 static void *make_alloc_exact(unsigned long addr, unsigned int order,
4913 		size_t size)
4914 {
4915 	if (addr) {
4916 		unsigned long alloc_end = addr + (PAGE_SIZE << order);
4917 		unsigned long used = addr + PAGE_ALIGN(size);
4918 
4919 		split_page(virt_to_page((void *)addr), order);
4920 		while (used < alloc_end) {
4921 			free_page(used);
4922 			used += PAGE_SIZE;
4923 		}
4924 	}
4925 	return (void *)addr;
4926 }
4927 
4928 /**
4929  * alloc_pages_exact - allocate an exact number physically-contiguous pages.
4930  * @size: the number of bytes to allocate
4931  * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
4932  *
4933  * This function is similar to alloc_pages(), except that it allocates the
4934  * minimum number of pages to satisfy the request.  alloc_pages() can only
4935  * allocate memory in power-of-two pages.
4936  *
4937  * This function is also limited by MAX_ORDER.
4938  *
4939  * Memory allocated by this function must be released by free_pages_exact().
4940  *
4941  * Return: pointer to the allocated area or %NULL in case of error.
4942  */
4943 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
4944 {
4945 	unsigned int order = get_order(size);
4946 	unsigned long addr;
4947 
4948 	if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
4949 		gfp_mask &= ~__GFP_COMP;
4950 
4951 	addr = __get_free_pages(gfp_mask, order);
4952 	return make_alloc_exact(addr, order, size);
4953 }
4954 EXPORT_SYMBOL(alloc_pages_exact);
4955 
4956 /**
4957  * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
4958  *			   pages on a node.
4959  * @nid: the preferred node ID where memory should be allocated
4960  * @size: the number of bytes to allocate
4961  * @gfp_mask: GFP flags for the allocation, must not contain __GFP_COMP
4962  *
4963  * Like alloc_pages_exact(), but try to allocate on node nid first before falling
4964  * back.
4965  *
4966  * Return: pointer to the allocated area or %NULL in case of error.
4967  */
4968 void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
4969 {
4970 	unsigned int order = get_order(size);
4971 	struct page *p;
4972 
4973 	if (WARN_ON_ONCE(gfp_mask & __GFP_COMP))
4974 		gfp_mask &= ~__GFP_COMP;
4975 
4976 	p = alloc_pages_node(nid, gfp_mask, order);
4977 	if (!p)
4978 		return NULL;
4979 	return make_alloc_exact((unsigned long)page_address(p), order, size);
4980 }
4981 
4982 /**
4983  * free_pages_exact - release memory allocated via alloc_pages_exact()
4984  * @virt: the value returned by alloc_pages_exact.
4985  * @size: size of allocation, same value as passed to alloc_pages_exact().
4986  *
4987  * Release the memory allocated by a previous call to alloc_pages_exact.
4988  */
4989 void free_pages_exact(void *virt, size_t size)
4990 {
4991 	unsigned long addr = (unsigned long)virt;
4992 	unsigned long end = addr + PAGE_ALIGN(size);
4993 
4994 	while (addr < end) {
4995 		free_page(addr);
4996 		addr += PAGE_SIZE;
4997 	}
4998 }
4999 EXPORT_SYMBOL(free_pages_exact);
5000 
5001 /**
5002  * nr_free_zone_pages - count number of pages beyond high watermark
5003  * @offset: The zone index of the highest zone
5004  *
5005  * nr_free_zone_pages() counts the number of pages which are beyond the
5006  * high watermark within all zones at or below a given zone index.  For each
5007  * zone, the number of pages is calculated as:
5008  *
5009  *     nr_free_zone_pages = managed_pages - high_pages
5010  *
5011  * Return: number of pages beyond high watermark.
5012  */
5013 static unsigned long nr_free_zone_pages(int offset)
5014 {
5015 	struct zoneref *z;
5016 	struct zone *zone;
5017 
5018 	/* Just pick one node, since fallback list is circular */
5019 	unsigned long sum = 0;
5020 
5021 	struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
5022 
5023 	for_each_zone_zonelist(zone, z, zonelist, offset) {
5024 		unsigned long size = zone_managed_pages(zone);
5025 		unsigned long high = high_wmark_pages(zone);
5026 		if (size > high)
5027 			sum += size - high;
5028 	}
5029 
5030 	return sum;
5031 }
5032 
5033 /**
5034  * nr_free_buffer_pages - count number of pages beyond high watermark
5035  *
5036  * nr_free_buffer_pages() counts the number of pages which are beyond the high
5037  * watermark within ZONE_DMA and ZONE_NORMAL.
5038  *
5039  * Return: number of pages beyond high watermark within ZONE_DMA and
5040  * ZONE_NORMAL.
5041  */
5042 unsigned long nr_free_buffer_pages(void)
5043 {
5044 	return nr_free_zone_pages(gfp_zone(GFP_USER));
5045 }
5046 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
5047 
5048 /**
5049  * nr_free_pagecache_pages - count number of pages beyond high watermark
5050  *
5051  * nr_free_pagecache_pages() counts the number of pages which are beyond the
5052  * high watermark within all zones.
5053  *
5054  * Return: number of pages beyond high watermark within all zones.
5055  */
5056 unsigned long nr_free_pagecache_pages(void)
5057 {
5058 	return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
5059 }
5060 
5061 static inline void show_node(struct zone *zone)
5062 {
5063 	if (IS_ENABLED(CONFIG_NUMA))
5064 		printk("Node %d ", zone_to_nid(zone));
5065 }
5066 
5067 long si_mem_available(void)
5068 {
5069 	long available;
5070 	unsigned long pagecache;
5071 	unsigned long wmark_low = 0;
5072 	unsigned long pages[NR_LRU_LISTS];
5073 	unsigned long reclaimable;
5074 	struct zone *zone;
5075 	int lru;
5076 
5077 	for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
5078 		pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
5079 
5080 	for_each_zone(zone)
5081 		wmark_low += low_wmark_pages(zone);
5082 
5083 	/*
5084 	 * Estimate the amount of memory available for userspace allocations,
5085 	 * without causing swapping.
5086 	 */
5087 	available = global_zone_page_state(NR_FREE_PAGES) - totalreserve_pages;
5088 
5089 	/*
5090 	 * Not all the page cache can be freed, otherwise the system will
5091 	 * start swapping. Assume at least half of the page cache, or the
5092 	 * low watermark worth of cache, needs to stay.
5093 	 */
5094 	pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
5095 	pagecache -= min(pagecache / 2, wmark_low);
5096 	available += pagecache;
5097 
5098 	/*
5099 	 * Part of the reclaimable slab and other kernel memory consists of
5100 	 * items that are in use, and cannot be freed. Cap this estimate at the
5101 	 * low watermark.
5102 	 */
5103 	reclaimable = global_node_page_state(NR_SLAB_RECLAIMABLE) +
5104 			global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
5105 	available += reclaimable - min(reclaimable / 2, wmark_low);
5106 
5107 	if (available < 0)
5108 		available = 0;
5109 	return available;
5110 }
5111 EXPORT_SYMBOL_GPL(si_mem_available);
5112 
5113 void si_meminfo(struct sysinfo *val)
5114 {
5115 	val->totalram = totalram_pages();
5116 	val->sharedram = global_node_page_state(NR_SHMEM);
5117 	val->freeram = global_zone_page_state(NR_FREE_PAGES);
5118 	val->bufferram = nr_blockdev_pages();
5119 	val->totalhigh = totalhigh_pages();
5120 	val->freehigh = nr_free_highpages();
5121 	val->mem_unit = PAGE_SIZE;
5122 }
5123 
5124 EXPORT_SYMBOL(si_meminfo);
5125 
5126 #ifdef CONFIG_NUMA
5127 void si_meminfo_node(struct sysinfo *val, int nid)
5128 {
5129 	int zone_type;		/* needs to be signed */
5130 	unsigned long managed_pages = 0;
5131 	unsigned long managed_highpages = 0;
5132 	unsigned long free_highpages = 0;
5133 	pg_data_t *pgdat = NODE_DATA(nid);
5134 
5135 	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
5136 		managed_pages += zone_managed_pages(&pgdat->node_zones[zone_type]);
5137 	val->totalram = managed_pages;
5138 	val->sharedram = node_page_state(pgdat, NR_SHMEM);
5139 	val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
5140 #ifdef CONFIG_HIGHMEM
5141 	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
5142 		struct zone *zone = &pgdat->node_zones[zone_type];
5143 
5144 		if (is_highmem(zone)) {
5145 			managed_highpages += zone_managed_pages(zone);
5146 			free_highpages += zone_page_state(zone, NR_FREE_PAGES);
5147 		}
5148 	}
5149 	val->totalhigh = managed_highpages;
5150 	val->freehigh = free_highpages;
5151 #else
5152 	val->totalhigh = managed_highpages;
5153 	val->freehigh = free_highpages;
5154 #endif
5155 	val->mem_unit = PAGE_SIZE;
5156 }
5157 #endif
5158 
5159 /*
5160  * Determine whether the node should be displayed or not, depending on whether
5161  * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
5162  */
5163 static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask)
5164 {
5165 	if (!(flags & SHOW_MEM_FILTER_NODES))
5166 		return false;
5167 
5168 	/*
5169 	 * no node mask - aka implicit memory numa policy. Do not bother with
5170 	 * the synchronization - read_mems_allowed_begin - because we do not
5171 	 * have to be precise here.
5172 	 */
5173 	if (!nodemask)
5174 		nodemask = &cpuset_current_mems_allowed;
5175 
5176 	return !node_isset(nid, *nodemask);
5177 }
5178 
5179 #define K(x) ((x) << (PAGE_SHIFT-10))
5180 
5181 static void show_migration_types(unsigned char type)
5182 {
5183 	static const char types[MIGRATE_TYPES] = {
5184 		[MIGRATE_UNMOVABLE]	= 'U',
5185 		[MIGRATE_MOVABLE]	= 'M',
5186 		[MIGRATE_RECLAIMABLE]	= 'E',
5187 		[MIGRATE_HIGHATOMIC]	= 'H',
5188 #ifdef CONFIG_CMA
5189 		[MIGRATE_CMA]		= 'C',
5190 #endif
5191 #ifdef CONFIG_MEMORY_ISOLATION
5192 		[MIGRATE_ISOLATE]	= 'I',
5193 #endif
5194 	};
5195 	char tmp[MIGRATE_TYPES + 1];
5196 	char *p = tmp;
5197 	int i;
5198 
5199 	for (i = 0; i < MIGRATE_TYPES; i++) {
5200 		if (type & (1 << i))
5201 			*p++ = types[i];
5202 	}
5203 
5204 	*p = '\0';
5205 	printk(KERN_CONT "(%s) ", tmp);
5206 }
5207 
5208 /*
5209  * Show free area list (used inside shift_scroll-lock stuff)
5210  * We also calculate the percentage fragmentation. We do this by counting the
5211  * memory on each free list with the exception of the first item on the list.
5212  *
5213  * Bits in @filter:
5214  * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
5215  *   cpuset.
5216  */
5217 void show_free_areas(unsigned int filter, nodemask_t *nodemask)
5218 {
5219 	unsigned long free_pcp = 0;
5220 	int cpu;
5221 	struct zone *zone;
5222 	pg_data_t *pgdat;
5223 
5224 	for_each_populated_zone(zone) {
5225 		if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5226 			continue;
5227 
5228 		for_each_online_cpu(cpu)
5229 			free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
5230 	}
5231 
5232 	printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
5233 		" active_file:%lu inactive_file:%lu isolated_file:%lu\n"
5234 		" unevictable:%lu dirty:%lu writeback:%lu unstable:%lu\n"
5235 		" slab_reclaimable:%lu slab_unreclaimable:%lu\n"
5236 		" mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
5237 		" free:%lu free_pcp:%lu free_cma:%lu\n",
5238 		global_node_page_state(NR_ACTIVE_ANON),
5239 		global_node_page_state(NR_INACTIVE_ANON),
5240 		global_node_page_state(NR_ISOLATED_ANON),
5241 		global_node_page_state(NR_ACTIVE_FILE),
5242 		global_node_page_state(NR_INACTIVE_FILE),
5243 		global_node_page_state(NR_ISOLATED_FILE),
5244 		global_node_page_state(NR_UNEVICTABLE),
5245 		global_node_page_state(NR_FILE_DIRTY),
5246 		global_node_page_state(NR_WRITEBACK),
5247 		global_node_page_state(NR_UNSTABLE_NFS),
5248 		global_node_page_state(NR_SLAB_RECLAIMABLE),
5249 		global_node_page_state(NR_SLAB_UNRECLAIMABLE),
5250 		global_node_page_state(NR_FILE_MAPPED),
5251 		global_node_page_state(NR_SHMEM),
5252 		global_zone_page_state(NR_PAGETABLE),
5253 		global_zone_page_state(NR_BOUNCE),
5254 		global_zone_page_state(NR_FREE_PAGES),
5255 		free_pcp,
5256 		global_zone_page_state(NR_FREE_CMA_PAGES));
5257 
5258 	for_each_online_pgdat(pgdat) {
5259 		if (show_mem_node_skip(filter, pgdat->node_id, nodemask))
5260 			continue;
5261 
5262 		printk("Node %d"
5263 			" active_anon:%lukB"
5264 			" inactive_anon:%lukB"
5265 			" active_file:%lukB"
5266 			" inactive_file:%lukB"
5267 			" unevictable:%lukB"
5268 			" isolated(anon):%lukB"
5269 			" isolated(file):%lukB"
5270 			" mapped:%lukB"
5271 			" dirty:%lukB"
5272 			" writeback:%lukB"
5273 			" shmem:%lukB"
5274 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5275 			" shmem_thp: %lukB"
5276 			" shmem_pmdmapped: %lukB"
5277 			" anon_thp: %lukB"
5278 #endif
5279 			" writeback_tmp:%lukB"
5280 			" unstable:%lukB"
5281 			" all_unreclaimable? %s"
5282 			"\n",
5283 			pgdat->node_id,
5284 			K(node_page_state(pgdat, NR_ACTIVE_ANON)),
5285 			K(node_page_state(pgdat, NR_INACTIVE_ANON)),
5286 			K(node_page_state(pgdat, NR_ACTIVE_FILE)),
5287 			K(node_page_state(pgdat, NR_INACTIVE_FILE)),
5288 			K(node_page_state(pgdat, NR_UNEVICTABLE)),
5289 			K(node_page_state(pgdat, NR_ISOLATED_ANON)),
5290 			K(node_page_state(pgdat, NR_ISOLATED_FILE)),
5291 			K(node_page_state(pgdat, NR_FILE_MAPPED)),
5292 			K(node_page_state(pgdat, NR_FILE_DIRTY)),
5293 			K(node_page_state(pgdat, NR_WRITEBACK)),
5294 			K(node_page_state(pgdat, NR_SHMEM)),
5295 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5296 			K(node_page_state(pgdat, NR_SHMEM_THPS) * HPAGE_PMD_NR),
5297 			K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)
5298 					* HPAGE_PMD_NR),
5299 			K(node_page_state(pgdat, NR_ANON_THPS) * HPAGE_PMD_NR),
5300 #endif
5301 			K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
5302 			K(node_page_state(pgdat, NR_UNSTABLE_NFS)),
5303 			pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ?
5304 				"yes" : "no");
5305 	}
5306 
5307 	for_each_populated_zone(zone) {
5308 		int i;
5309 
5310 		if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5311 			continue;
5312 
5313 		free_pcp = 0;
5314 		for_each_online_cpu(cpu)
5315 			free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
5316 
5317 		show_node(zone);
5318 		printk(KERN_CONT
5319 			"%s"
5320 			" free:%lukB"
5321 			" min:%lukB"
5322 			" low:%lukB"
5323 			" high:%lukB"
5324 			" active_anon:%lukB"
5325 			" inactive_anon:%lukB"
5326 			" active_file:%lukB"
5327 			" inactive_file:%lukB"
5328 			" unevictable:%lukB"
5329 			" writepending:%lukB"
5330 			" present:%lukB"
5331 			" managed:%lukB"
5332 			" mlocked:%lukB"
5333 			" kernel_stack:%lukB"
5334 			" pagetables:%lukB"
5335 			" bounce:%lukB"
5336 			" free_pcp:%lukB"
5337 			" local_pcp:%ukB"
5338 			" free_cma:%lukB"
5339 			"\n",
5340 			zone->name,
5341 			K(zone_page_state(zone, NR_FREE_PAGES)),
5342 			K(min_wmark_pages(zone)),
5343 			K(low_wmark_pages(zone)),
5344 			K(high_wmark_pages(zone)),
5345 			K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)),
5346 			K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)),
5347 			K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
5348 			K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
5349 			K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
5350 			K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
5351 			K(zone->present_pages),
5352 			K(zone_managed_pages(zone)),
5353 			K(zone_page_state(zone, NR_MLOCK)),
5354 			zone_page_state(zone, NR_KERNEL_STACK_KB),
5355 			K(zone_page_state(zone, NR_PAGETABLE)),
5356 			K(zone_page_state(zone, NR_BOUNCE)),
5357 			K(free_pcp),
5358 			K(this_cpu_read(zone->pageset->pcp.count)),
5359 			K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
5360 		printk("lowmem_reserve[]:");
5361 		for (i = 0; i < MAX_NR_ZONES; i++)
5362 			printk(KERN_CONT " %ld", zone->lowmem_reserve[i]);
5363 		printk(KERN_CONT "\n");
5364 	}
5365 
5366 	for_each_populated_zone(zone) {
5367 		unsigned int order;
5368 		unsigned long nr[MAX_ORDER], flags, total = 0;
5369 		unsigned char types[MAX_ORDER];
5370 
5371 		if (show_mem_node_skip(filter, zone_to_nid(zone), nodemask))
5372 			continue;
5373 		show_node(zone);
5374 		printk(KERN_CONT "%s: ", zone->name);
5375 
5376 		spin_lock_irqsave(&zone->lock, flags);
5377 		for (order = 0; order < MAX_ORDER; order++) {
5378 			struct free_area *area = &zone->free_area[order];
5379 			int type;
5380 
5381 			nr[order] = area->nr_free;
5382 			total += nr[order] << order;
5383 
5384 			types[order] = 0;
5385 			for (type = 0; type < MIGRATE_TYPES; type++) {
5386 				if (!free_area_empty(area, type))
5387 					types[order] |= 1 << type;
5388 			}
5389 		}
5390 		spin_unlock_irqrestore(&zone->lock, flags);
5391 		for (order = 0; order < MAX_ORDER; order++) {
5392 			printk(KERN_CONT "%lu*%lukB ",
5393 			       nr[order], K(1UL) << order);
5394 			if (nr[order])
5395 				show_migration_types(types[order]);
5396 		}
5397 		printk(KERN_CONT "= %lukB\n", K(total));
5398 	}
5399 
5400 	hugetlb_show_meminfo();
5401 
5402 	printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
5403 
5404 	show_swap_cache_info();
5405 }
5406 
5407 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
5408 {
5409 	zoneref->zone = zone;
5410 	zoneref->zone_idx = zone_idx(zone);
5411 }
5412 
5413 /*
5414  * Builds allocation fallback zone lists.
5415  *
5416  * Add all populated zones of a node to the zonelist.
5417  */
5418 static int build_zonerefs_node(pg_data_t *pgdat, struct zoneref *zonerefs)
5419 {
5420 	struct zone *zone;
5421 	enum zone_type zone_type = MAX_NR_ZONES;
5422 	int nr_zones = 0;
5423 
5424 	do {
5425 		zone_type--;
5426 		zone = pgdat->node_zones + zone_type;
5427 		if (managed_zone(zone)) {
5428 			zoneref_set_zone(zone, &zonerefs[nr_zones++]);
5429 			check_highest_zone(zone_type);
5430 		}
5431 	} while (zone_type);
5432 
5433 	return nr_zones;
5434 }
5435 
5436 #ifdef CONFIG_NUMA
5437 
5438 static int __parse_numa_zonelist_order(char *s)
5439 {
5440 	/*
5441 	 * We used to support different zonlists modes but they turned
5442 	 * out to be just not useful. Let's keep the warning in place
5443 	 * if somebody still use the cmd line parameter so that we do
5444 	 * not fail it silently
5445 	 */
5446 	if (!(*s == 'd' || *s == 'D' || *s == 'n' || *s == 'N')) {
5447 		pr_warn("Ignoring unsupported numa_zonelist_order value:  %s\n", s);
5448 		return -EINVAL;
5449 	}
5450 	return 0;
5451 }
5452 
5453 static __init int setup_numa_zonelist_order(char *s)
5454 {
5455 	if (!s)
5456 		return 0;
5457 
5458 	return __parse_numa_zonelist_order(s);
5459 }
5460 early_param("numa_zonelist_order", setup_numa_zonelist_order);
5461 
5462 char numa_zonelist_order[] = "Node";
5463 
5464 /*
5465  * sysctl handler for numa_zonelist_order
5466  */
5467 int numa_zonelist_order_handler(struct ctl_table *table, int write,
5468 		void __user *buffer, size_t *length,
5469 		loff_t *ppos)
5470 {
5471 	char *str;
5472 	int ret;
5473 
5474 	if (!write)
5475 		return proc_dostring(table, write, buffer, length, ppos);
5476 	str = memdup_user_nul(buffer, 16);
5477 	if (IS_ERR(str))
5478 		return PTR_ERR(str);
5479 
5480 	ret = __parse_numa_zonelist_order(str);
5481 	kfree(str);
5482 	return ret;
5483 }
5484 
5485 
5486 #define MAX_NODE_LOAD (nr_online_nodes)
5487 static int node_load[MAX_NUMNODES];
5488 
5489 /**
5490  * find_next_best_node - find the next node that should appear in a given node's fallback list
5491  * @node: node whose fallback list we're appending
5492  * @used_node_mask: nodemask_t of already used nodes
5493  *
5494  * We use a number of factors to determine which is the next node that should
5495  * appear on a given node's fallback list.  The node should not have appeared
5496  * already in @node's fallback list, and it should be the next closest node
5497  * according to the distance array (which contains arbitrary distance values
5498  * from each node to each node in the system), and should also prefer nodes
5499  * with no CPUs, since presumably they'll have very little allocation pressure
5500  * on them otherwise.
5501  *
5502  * Return: node id of the found node or %NUMA_NO_NODE if no node is found.
5503  */
5504 static int find_next_best_node(int node, nodemask_t *used_node_mask)
5505 {
5506 	int n, val;
5507 	int min_val = INT_MAX;
5508 	int best_node = NUMA_NO_NODE;
5509 	const struct cpumask *tmp = cpumask_of_node(0);
5510 
5511 	/* Use the local node if we haven't already */
5512 	if (!node_isset(node, *used_node_mask)) {
5513 		node_set(node, *used_node_mask);
5514 		return node;
5515 	}
5516 
5517 	for_each_node_state(n, N_MEMORY) {
5518 
5519 		/* Don't want a node to appear more than once */
5520 		if (node_isset(n, *used_node_mask))
5521 			continue;
5522 
5523 		/* Use the distance array to find the distance */
5524 		val = node_distance(node, n);
5525 
5526 		/* Penalize nodes under us ("prefer the next node") */
5527 		val += (n < node);
5528 
5529 		/* Give preference to headless and unused nodes */
5530 		tmp = cpumask_of_node(n);
5531 		if (!cpumask_empty(tmp))
5532 			val += PENALTY_FOR_NODE_WITH_CPUS;
5533 
5534 		/* Slight preference for less loaded node */
5535 		val *= (MAX_NODE_LOAD*MAX_NUMNODES);
5536 		val += node_load[n];
5537 
5538 		if (val < min_val) {
5539 			min_val = val;
5540 			best_node = n;
5541 		}
5542 	}
5543 
5544 	if (best_node >= 0)
5545 		node_set(best_node, *used_node_mask);
5546 
5547 	return best_node;
5548 }
5549 
5550 
5551 /*
5552  * Build zonelists ordered by node and zones within node.
5553  * This results in maximum locality--normal zone overflows into local
5554  * DMA zone, if any--but risks exhausting DMA zone.
5555  */
5556 static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order,
5557 		unsigned nr_nodes)
5558 {
5559 	struct zoneref *zonerefs;
5560 	int i;
5561 
5562 	zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
5563 
5564 	for (i = 0; i < nr_nodes; i++) {
5565 		int nr_zones;
5566 
5567 		pg_data_t *node = NODE_DATA(node_order[i]);
5568 
5569 		nr_zones = build_zonerefs_node(node, zonerefs);
5570 		zonerefs += nr_zones;
5571 	}
5572 	zonerefs->zone = NULL;
5573 	zonerefs->zone_idx = 0;
5574 }
5575 
5576 /*
5577  * Build gfp_thisnode zonelists
5578  */
5579 static void build_thisnode_zonelists(pg_data_t *pgdat)
5580 {
5581 	struct zoneref *zonerefs;
5582 	int nr_zones;
5583 
5584 	zonerefs = pgdat->node_zonelists[ZONELIST_NOFALLBACK]._zonerefs;
5585 	nr_zones = build_zonerefs_node(pgdat, zonerefs);
5586 	zonerefs += nr_zones;
5587 	zonerefs->zone = NULL;
5588 	zonerefs->zone_idx = 0;
5589 }
5590 
5591 /*
5592  * Build zonelists ordered by zone and nodes within zones.
5593  * This results in conserving DMA zone[s] until all Normal memory is
5594  * exhausted, but results in overflowing to remote node while memory
5595  * may still exist in local DMA zone.
5596  */
5597 
5598 static void build_zonelists(pg_data_t *pgdat)
5599 {
5600 	static int node_order[MAX_NUMNODES];
5601 	int node, load, nr_nodes = 0;
5602 	nodemask_t used_mask;
5603 	int local_node, prev_node;
5604 
5605 	/* NUMA-aware ordering of nodes */
5606 	local_node = pgdat->node_id;
5607 	load = nr_online_nodes;
5608 	prev_node = local_node;
5609 	nodes_clear(used_mask);
5610 
5611 	memset(node_order, 0, sizeof(node_order));
5612 	while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
5613 		/*
5614 		 * We don't want to pressure a particular node.
5615 		 * So adding penalty to the first node in same
5616 		 * distance group to make it round-robin.
5617 		 */
5618 		if (node_distance(local_node, node) !=
5619 		    node_distance(local_node, prev_node))
5620 			node_load[node] = load;
5621 
5622 		node_order[nr_nodes++] = node;
5623 		prev_node = node;
5624 		load--;
5625 	}
5626 
5627 	build_zonelists_in_node_order(pgdat, node_order, nr_nodes);
5628 	build_thisnode_zonelists(pgdat);
5629 }
5630 
5631 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
5632 /*
5633  * Return node id of node used for "local" allocations.
5634  * I.e., first node id of first zone in arg node's generic zonelist.
5635  * Used for initializing percpu 'numa_mem', which is used primarily
5636  * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
5637  */
5638 int local_memory_node(int node)
5639 {
5640 	struct zoneref *z;
5641 
5642 	z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
5643 				   gfp_zone(GFP_KERNEL),
5644 				   NULL);
5645 	return zone_to_nid(z->zone);
5646 }
5647 #endif
5648 
5649 static void setup_min_unmapped_ratio(void);
5650 static void setup_min_slab_ratio(void);
5651 #else	/* CONFIG_NUMA */
5652 
5653 static void build_zonelists(pg_data_t *pgdat)
5654 {
5655 	int node, local_node;
5656 	struct zoneref *zonerefs;
5657 	int nr_zones;
5658 
5659 	local_node = pgdat->node_id;
5660 
5661 	zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs;
5662 	nr_zones = build_zonerefs_node(pgdat, zonerefs);
5663 	zonerefs += nr_zones;
5664 
5665 	/*
5666 	 * Now we build the zonelist so that it contains the zones
5667 	 * of all the other nodes.
5668 	 * We don't want to pressure a particular node, so when
5669 	 * building the zones for node N, we make sure that the
5670 	 * zones coming right after the local ones are those from
5671 	 * node N+1 (modulo N)
5672 	 */
5673 	for (node = local_node + 1; node < MAX_NUMNODES; node++) {
5674 		if (!node_online(node))
5675 			continue;
5676 		nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
5677 		zonerefs += nr_zones;
5678 	}
5679 	for (node = 0; node < local_node; node++) {
5680 		if (!node_online(node))
5681 			continue;
5682 		nr_zones = build_zonerefs_node(NODE_DATA(node), zonerefs);
5683 		zonerefs += nr_zones;
5684 	}
5685 
5686 	zonerefs->zone = NULL;
5687 	zonerefs->zone_idx = 0;
5688 }
5689 
5690 #endif	/* CONFIG_NUMA */
5691 
5692 /*
5693  * Boot pageset table. One per cpu which is going to be used for all
5694  * zones and all nodes. The parameters will be set in such a way
5695  * that an item put on a list will immediately be handed over to
5696  * the buddy list. This is safe since pageset manipulation is done
5697  * with interrupts disabled.
5698  *
5699  * The boot_pagesets must be kept even after bootup is complete for
5700  * unused processors and/or zones. They do play a role for bootstrapping
5701  * hotplugged processors.
5702  *
5703  * zoneinfo_show() and maybe other functions do
5704  * not check if the processor is online before following the pageset pointer.
5705  * Other parts of the kernel may not check if the zone is available.
5706  */
5707 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
5708 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
5709 static DEFINE_PER_CPU(struct per_cpu_nodestat, boot_nodestats);
5710 
5711 static void __build_all_zonelists(void *data)
5712 {
5713 	int nid;
5714 	int __maybe_unused cpu;
5715 	pg_data_t *self = data;
5716 	static DEFINE_SPINLOCK(lock);
5717 
5718 	spin_lock(&lock);
5719 
5720 #ifdef CONFIG_NUMA
5721 	memset(node_load, 0, sizeof(node_load));
5722 #endif
5723 
5724 	/*
5725 	 * This node is hotadded and no memory is yet present.   So just
5726 	 * building zonelists is fine - no need to touch other nodes.
5727 	 */
5728 	if (self && !node_online(self->node_id)) {
5729 		build_zonelists(self);
5730 	} else {
5731 		for_each_online_node(nid) {
5732 			pg_data_t *pgdat = NODE_DATA(nid);
5733 
5734 			build_zonelists(pgdat);
5735 		}
5736 
5737 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
5738 		/*
5739 		 * We now know the "local memory node" for each node--
5740 		 * i.e., the node of the first zone in the generic zonelist.
5741 		 * Set up numa_mem percpu variable for on-line cpus.  During
5742 		 * boot, only the boot cpu should be on-line;  we'll init the
5743 		 * secondary cpus' numa_mem as they come on-line.  During
5744 		 * node/memory hotplug, we'll fixup all on-line cpus.
5745 		 */
5746 		for_each_online_cpu(cpu)
5747 			set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
5748 #endif
5749 	}
5750 
5751 	spin_unlock(&lock);
5752 }
5753 
5754 static noinline void __init
5755 build_all_zonelists_init(void)
5756 {
5757 	int cpu;
5758 
5759 	__build_all_zonelists(NULL);
5760 
5761 	/*
5762 	 * Initialize the boot_pagesets that are going to be used
5763 	 * for bootstrapping processors. The real pagesets for
5764 	 * each zone will be allocated later when the per cpu
5765 	 * allocator is available.
5766 	 *
5767 	 * boot_pagesets are used also for bootstrapping offline
5768 	 * cpus if the system is already booted because the pagesets
5769 	 * are needed to initialize allocators on a specific cpu too.
5770 	 * F.e. the percpu allocator needs the page allocator which
5771 	 * needs the percpu allocator in order to allocate its pagesets
5772 	 * (a chicken-egg dilemma).
5773 	 */
5774 	for_each_possible_cpu(cpu)
5775 		setup_pageset(&per_cpu(boot_pageset, cpu), 0);
5776 
5777 	mminit_verify_zonelist();
5778 	cpuset_init_current_mems_allowed();
5779 }
5780 
5781 /*
5782  * unless system_state == SYSTEM_BOOTING.
5783  *
5784  * __ref due to call of __init annotated helper build_all_zonelists_init
5785  * [protected by SYSTEM_BOOTING].
5786  */
5787 void __ref build_all_zonelists(pg_data_t *pgdat)
5788 {
5789 	if (system_state == SYSTEM_BOOTING) {
5790 		build_all_zonelists_init();
5791 	} else {
5792 		__build_all_zonelists(pgdat);
5793 		/* cpuset refresh routine should be here */
5794 	}
5795 	vm_total_pages = nr_free_pagecache_pages();
5796 	/*
5797 	 * Disable grouping by mobility if the number of pages in the
5798 	 * system is too low to allow the mechanism to work. It would be
5799 	 * more accurate, but expensive to check per-zone. This check is
5800 	 * made on memory-hotadd so a system can start with mobility
5801 	 * disabled and enable it later
5802 	 */
5803 	if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
5804 		page_group_by_mobility_disabled = 1;
5805 	else
5806 		page_group_by_mobility_disabled = 0;
5807 
5808 	pr_info("Built %u zonelists, mobility grouping %s.  Total pages: %ld\n",
5809 		nr_online_nodes,
5810 		page_group_by_mobility_disabled ? "off" : "on",
5811 		vm_total_pages);
5812 #ifdef CONFIG_NUMA
5813 	pr_info("Policy zone: %s\n", zone_names[policy_zone]);
5814 #endif
5815 }
5816 
5817 /* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
5818 static bool __meminit
5819 overlap_memmap_init(unsigned long zone, unsigned long *pfn)
5820 {
5821 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5822 	static struct memblock_region *r;
5823 
5824 	if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
5825 		if (!r || *pfn >= memblock_region_memory_end_pfn(r)) {
5826 			for_each_memblock(memory, r) {
5827 				if (*pfn < memblock_region_memory_end_pfn(r))
5828 					break;
5829 			}
5830 		}
5831 		if (*pfn >= memblock_region_memory_base_pfn(r) &&
5832 		    memblock_is_mirror(r)) {
5833 			*pfn = memblock_region_memory_end_pfn(r);
5834 			return true;
5835 		}
5836 	}
5837 #endif
5838 	return false;
5839 }
5840 
5841 /*
5842  * Initially all pages are reserved - free ones are freed
5843  * up by memblock_free_all() once the early boot process is
5844  * done. Non-atomic initialization, single-pass.
5845  */
5846 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
5847 		unsigned long start_pfn, enum memmap_context context,
5848 		struct vmem_altmap *altmap)
5849 {
5850 	unsigned long pfn, end_pfn = start_pfn + size;
5851 	struct page *page;
5852 
5853 	if (highest_memmap_pfn < end_pfn - 1)
5854 		highest_memmap_pfn = end_pfn - 1;
5855 
5856 #ifdef CONFIG_ZONE_DEVICE
5857 	/*
5858 	 * Honor reservation requested by the driver for this ZONE_DEVICE
5859 	 * memory. We limit the total number of pages to initialize to just
5860 	 * those that might contain the memory mapping. We will defer the
5861 	 * ZONE_DEVICE page initialization until after we have released
5862 	 * the hotplug lock.
5863 	 */
5864 	if (zone == ZONE_DEVICE) {
5865 		if (!altmap)
5866 			return;
5867 
5868 		if (start_pfn == altmap->base_pfn)
5869 			start_pfn += altmap->reserve;
5870 		end_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
5871 	}
5872 #endif
5873 
5874 	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
5875 		/*
5876 		 * There can be holes in boot-time mem_map[]s handed to this
5877 		 * function.  They do not exist on hotplugged memory.
5878 		 */
5879 		if (context == MEMMAP_EARLY) {
5880 			if (!early_pfn_valid(pfn))
5881 				continue;
5882 			if (!early_pfn_in_nid(pfn, nid))
5883 				continue;
5884 			if (overlap_memmap_init(zone, &pfn))
5885 				continue;
5886 			if (defer_init(nid, pfn, end_pfn))
5887 				break;
5888 		}
5889 
5890 		page = pfn_to_page(pfn);
5891 		__init_single_page(page, pfn, zone, nid);
5892 		if (context == MEMMAP_HOTPLUG)
5893 			__SetPageReserved(page);
5894 
5895 		/*
5896 		 * Mark the block movable so that blocks are reserved for
5897 		 * movable at startup. This will force kernel allocations
5898 		 * to reserve their blocks rather than leaking throughout
5899 		 * the address space during boot when many long-lived
5900 		 * kernel allocations are made.
5901 		 *
5902 		 * bitmap is created for zone's valid pfn range. but memmap
5903 		 * can be created for invalid pages (for alignment)
5904 		 * check here not to call set_pageblock_migratetype() against
5905 		 * pfn out of zone.
5906 		 */
5907 		if (!(pfn & (pageblock_nr_pages - 1))) {
5908 			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5909 			cond_resched();
5910 		}
5911 	}
5912 }
5913 
5914 #ifdef CONFIG_ZONE_DEVICE
5915 void __ref memmap_init_zone_device(struct zone *zone,
5916 				   unsigned long start_pfn,
5917 				   unsigned long size,
5918 				   struct dev_pagemap *pgmap)
5919 {
5920 	unsigned long pfn, end_pfn = start_pfn + size;
5921 	struct pglist_data *pgdat = zone->zone_pgdat;
5922 	struct vmem_altmap *altmap = pgmap_altmap(pgmap);
5923 	unsigned long zone_idx = zone_idx(zone);
5924 	unsigned long start = jiffies;
5925 	int nid = pgdat->node_id;
5926 
5927 	if (WARN_ON_ONCE(!pgmap || zone_idx(zone) != ZONE_DEVICE))
5928 		return;
5929 
5930 	/*
5931 	 * The call to memmap_init_zone should have already taken care
5932 	 * of the pages reserved for the memmap, so we can just jump to
5933 	 * the end of that region and start processing the device pages.
5934 	 */
5935 	if (altmap) {
5936 		start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap);
5937 		size = end_pfn - start_pfn;
5938 	}
5939 
5940 	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
5941 		struct page *page = pfn_to_page(pfn);
5942 
5943 		__init_single_page(page, pfn, zone_idx, nid);
5944 
5945 		/*
5946 		 * Mark page reserved as it will need to wait for onlining
5947 		 * phase for it to be fully associated with a zone.
5948 		 *
5949 		 * We can use the non-atomic __set_bit operation for setting
5950 		 * the flag as we are still initializing the pages.
5951 		 */
5952 		__SetPageReserved(page);
5953 
5954 		/*
5955 		 * ZONE_DEVICE pages union ->lru with a ->pgmap back pointer
5956 		 * and zone_device_data.  It is a bug if a ZONE_DEVICE page is
5957 		 * ever freed or placed on a driver-private list.
5958 		 */
5959 		page->pgmap = pgmap;
5960 		page->zone_device_data = NULL;
5961 
5962 		/*
5963 		 * Mark the block movable so that blocks are reserved for
5964 		 * movable at startup. This will force kernel allocations
5965 		 * to reserve their blocks rather than leaking throughout
5966 		 * the address space during boot when many long-lived
5967 		 * kernel allocations are made.
5968 		 *
5969 		 * bitmap is created for zone's valid pfn range. but memmap
5970 		 * can be created for invalid pages (for alignment)
5971 		 * check here not to call set_pageblock_migratetype() against
5972 		 * pfn out of zone.
5973 		 *
5974 		 * Please note that MEMMAP_HOTPLUG path doesn't clear memmap
5975 		 * because this is done early in section_activate()
5976 		 */
5977 		if (!(pfn & (pageblock_nr_pages - 1))) {
5978 			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5979 			cond_resched();
5980 		}
5981 	}
5982 
5983 	pr_info("%s initialised %lu pages in %ums\n", __func__,
5984 		size, jiffies_to_msecs(jiffies - start));
5985 }
5986 
5987 #endif
5988 static void __meminit zone_init_free_lists(struct zone *zone)
5989 {
5990 	unsigned int order, t;
5991 	for_each_migratetype_order(order, t) {
5992 		INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
5993 		zone->free_area[order].nr_free = 0;
5994 	}
5995 }
5996 
5997 void __meminit __weak memmap_init(unsigned long size, int nid,
5998 				  unsigned long zone, unsigned long start_pfn)
5999 {
6000 	memmap_init_zone(size, nid, zone, start_pfn, MEMMAP_EARLY, NULL);
6001 }
6002 
6003 static int zone_batchsize(struct zone *zone)
6004 {
6005 #ifdef CONFIG_MMU
6006 	int batch;
6007 
6008 	/*
6009 	 * The per-cpu-pages pools are set to around 1000th of the
6010 	 * size of the zone.
6011 	 */
6012 	batch = zone_managed_pages(zone) / 1024;
6013 	/* But no more than a meg. */
6014 	if (batch * PAGE_SIZE > 1024 * 1024)
6015 		batch = (1024 * 1024) / PAGE_SIZE;
6016 	batch /= 4;		/* We effectively *= 4 below */
6017 	if (batch < 1)
6018 		batch = 1;
6019 
6020 	/*
6021 	 * Clamp the batch to a 2^n - 1 value. Having a power
6022 	 * of 2 value was found to be more likely to have
6023 	 * suboptimal cache aliasing properties in some cases.
6024 	 *
6025 	 * For example if 2 tasks are alternately allocating
6026 	 * batches of pages, one task can end up with a lot
6027 	 * of pages of one half of the possible page colors
6028 	 * and the other with pages of the other colors.
6029 	 */
6030 	batch = rounddown_pow_of_two(batch + batch/2) - 1;
6031 
6032 	return batch;
6033 
6034 #else
6035 	/* The deferral and batching of frees should be suppressed under NOMMU
6036 	 * conditions.
6037 	 *
6038 	 * The problem is that NOMMU needs to be able to allocate large chunks
6039 	 * of contiguous memory as there's no hardware page translation to
6040 	 * assemble apparent contiguous memory from discontiguous pages.
6041 	 *
6042 	 * Queueing large contiguous runs of pages for batching, however,
6043 	 * causes the pages to actually be freed in smaller chunks.  As there
6044 	 * can be a significant delay between the individual batches being
6045 	 * recycled, this leads to the once large chunks of space being
6046 	 * fragmented and becoming unavailable for high-order allocations.
6047 	 */
6048 	return 0;
6049 #endif
6050 }
6051 
6052 /*
6053  * pcp->high and pcp->batch values are related and dependent on one another:
6054  * ->batch must never be higher then ->high.
6055  * The following function updates them in a safe manner without read side
6056  * locking.
6057  *
6058  * Any new users of pcp->batch and pcp->high should ensure they can cope with
6059  * those fields changing asynchronously (acording the the above rule).
6060  *
6061  * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
6062  * outside of boot time (or some other assurance that no concurrent updaters
6063  * exist).
6064  */
6065 static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
6066 		unsigned long batch)
6067 {
6068        /* start with a fail safe value for batch */
6069 	pcp->batch = 1;
6070 	smp_wmb();
6071 
6072        /* Update high, then batch, in order */
6073 	pcp->high = high;
6074 	smp_wmb();
6075 
6076 	pcp->batch = batch;
6077 }
6078 
6079 /* a companion to pageset_set_high() */
6080 static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
6081 {
6082 	pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
6083 }
6084 
6085 static void pageset_init(struct per_cpu_pageset *p)
6086 {
6087 	struct per_cpu_pages *pcp;
6088 	int migratetype;
6089 
6090 	memset(p, 0, sizeof(*p));
6091 
6092 	pcp = &p->pcp;
6093 	for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
6094 		INIT_LIST_HEAD(&pcp->lists[migratetype]);
6095 }
6096 
6097 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
6098 {
6099 	pageset_init(p);
6100 	pageset_set_batch(p, batch);
6101 }
6102 
6103 /*
6104  * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
6105  * to the value high for the pageset p.
6106  */
6107 static void pageset_set_high(struct per_cpu_pageset *p,
6108 				unsigned long high)
6109 {
6110 	unsigned long batch = max(1UL, high / 4);
6111 	if ((high / 4) > (PAGE_SHIFT * 8))
6112 		batch = PAGE_SHIFT * 8;
6113 
6114 	pageset_update(&p->pcp, high, batch);
6115 }
6116 
6117 static void pageset_set_high_and_batch(struct zone *zone,
6118 				       struct per_cpu_pageset *pcp)
6119 {
6120 	if (percpu_pagelist_fraction)
6121 		pageset_set_high(pcp,
6122 			(zone_managed_pages(zone) /
6123 				percpu_pagelist_fraction));
6124 	else
6125 		pageset_set_batch(pcp, zone_batchsize(zone));
6126 }
6127 
6128 static void __meminit zone_pageset_init(struct zone *zone, int cpu)
6129 {
6130 	struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
6131 
6132 	pageset_init(pcp);
6133 	pageset_set_high_and_batch(zone, pcp);
6134 }
6135 
6136 void __meminit setup_zone_pageset(struct zone *zone)
6137 {
6138 	int cpu;
6139 	zone->pageset = alloc_percpu(struct per_cpu_pageset);
6140 	for_each_possible_cpu(cpu)
6141 		zone_pageset_init(zone, cpu);
6142 }
6143 
6144 /*
6145  * Allocate per cpu pagesets and initialize them.
6146  * Before this call only boot pagesets were available.
6147  */
6148 void __init setup_per_cpu_pageset(void)
6149 {
6150 	struct pglist_data *pgdat;
6151 	struct zone *zone;
6152 
6153 	for_each_populated_zone(zone)
6154 		setup_zone_pageset(zone);
6155 
6156 	for_each_online_pgdat(pgdat)
6157 		pgdat->per_cpu_nodestats =
6158 			alloc_percpu(struct per_cpu_nodestat);
6159 }
6160 
6161 static __meminit void zone_pcp_init(struct zone *zone)
6162 {
6163 	/*
6164 	 * per cpu subsystem is not up at this point. The following code
6165 	 * relies on the ability of the linker to provide the
6166 	 * offset of a (static) per cpu variable into the per cpu area.
6167 	 */
6168 	zone->pageset = &boot_pageset;
6169 
6170 	if (populated_zone(zone))
6171 		printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%u\n",
6172 			zone->name, zone->present_pages,
6173 					 zone_batchsize(zone));
6174 }
6175 
6176 void __meminit init_currently_empty_zone(struct zone *zone,
6177 					unsigned long zone_start_pfn,
6178 					unsigned long size)
6179 {
6180 	struct pglist_data *pgdat = zone->zone_pgdat;
6181 	int zone_idx = zone_idx(zone) + 1;
6182 
6183 	if (zone_idx > pgdat->nr_zones)
6184 		pgdat->nr_zones = zone_idx;
6185 
6186 	zone->zone_start_pfn = zone_start_pfn;
6187 
6188 	mminit_dprintk(MMINIT_TRACE, "memmap_init",
6189 			"Initialising map node %d zone %lu pfns %lu -> %lu\n",
6190 			pgdat->node_id,
6191 			(unsigned long)zone_idx(zone),
6192 			zone_start_pfn, (zone_start_pfn + size));
6193 
6194 	zone_init_free_lists(zone);
6195 	zone->initialized = 1;
6196 }
6197 
6198 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
6199 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
6200 
6201 /*
6202  * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
6203  */
6204 int __meminit __early_pfn_to_nid(unsigned long pfn,
6205 					struct mminit_pfnnid_cache *state)
6206 {
6207 	unsigned long start_pfn, end_pfn;
6208 	int nid;
6209 
6210 	if (state->last_start <= pfn && pfn < state->last_end)
6211 		return state->last_nid;
6212 
6213 	nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
6214 	if (nid != NUMA_NO_NODE) {
6215 		state->last_start = start_pfn;
6216 		state->last_end = end_pfn;
6217 		state->last_nid = nid;
6218 	}
6219 
6220 	return nid;
6221 }
6222 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
6223 
6224 /**
6225  * free_bootmem_with_active_regions - Call memblock_free_early_nid for each active range
6226  * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
6227  * @max_low_pfn: The highest PFN that will be passed to memblock_free_early_nid
6228  *
6229  * If an architecture guarantees that all ranges registered contain no holes
6230  * and may be freed, this this function may be used instead of calling
6231  * memblock_free_early_nid() manually.
6232  */
6233 void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
6234 {
6235 	unsigned long start_pfn, end_pfn;
6236 	int i, this_nid;
6237 
6238 	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
6239 		start_pfn = min(start_pfn, max_low_pfn);
6240 		end_pfn = min(end_pfn, max_low_pfn);
6241 
6242 		if (start_pfn < end_pfn)
6243 			memblock_free_early_nid(PFN_PHYS(start_pfn),
6244 					(end_pfn - start_pfn) << PAGE_SHIFT,
6245 					this_nid);
6246 	}
6247 }
6248 
6249 /**
6250  * sparse_memory_present_with_active_regions - Call memory_present for each active range
6251  * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
6252  *
6253  * If an architecture guarantees that all ranges registered contain no holes and may
6254  * be freed, this function may be used instead of calling memory_present() manually.
6255  */
6256 void __init sparse_memory_present_with_active_regions(int nid)
6257 {
6258 	unsigned long start_pfn, end_pfn;
6259 	int i, this_nid;
6260 
6261 	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
6262 		memory_present(this_nid, start_pfn, end_pfn);
6263 }
6264 
6265 /**
6266  * get_pfn_range_for_nid - Return the start and end page frames for a node
6267  * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
6268  * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
6269  * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
6270  *
6271  * It returns the start and end page frame of a node based on information
6272  * provided by memblock_set_node(). If called for a node
6273  * with no available memory, a warning is printed and the start and end
6274  * PFNs will be 0.
6275  */
6276 void __init get_pfn_range_for_nid(unsigned int nid,
6277 			unsigned long *start_pfn, unsigned long *end_pfn)
6278 {
6279 	unsigned long this_start_pfn, this_end_pfn;
6280 	int i;
6281 
6282 	*start_pfn = -1UL;
6283 	*end_pfn = 0;
6284 
6285 	for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
6286 		*start_pfn = min(*start_pfn, this_start_pfn);
6287 		*end_pfn = max(*end_pfn, this_end_pfn);
6288 	}
6289 
6290 	if (*start_pfn == -1UL)
6291 		*start_pfn = 0;
6292 }
6293 
6294 /*
6295  * This finds a zone that can be used for ZONE_MOVABLE pages. The
6296  * assumption is made that zones within a node are ordered in monotonic
6297  * increasing memory addresses so that the "highest" populated zone is used
6298  */
6299 static void __init find_usable_zone_for_movable(void)
6300 {
6301 	int zone_index;
6302 	for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
6303 		if (zone_index == ZONE_MOVABLE)
6304 			continue;
6305 
6306 		if (arch_zone_highest_possible_pfn[zone_index] >
6307 				arch_zone_lowest_possible_pfn[zone_index])
6308 			break;
6309 	}
6310 
6311 	VM_BUG_ON(zone_index == -1);
6312 	movable_zone = zone_index;
6313 }
6314 
6315 /*
6316  * The zone ranges provided by the architecture do not include ZONE_MOVABLE
6317  * because it is sized independent of architecture. Unlike the other zones,
6318  * the starting point for ZONE_MOVABLE is not fixed. It may be different
6319  * in each node depending on the size of each node and how evenly kernelcore
6320  * is distributed. This helper function adjusts the zone ranges
6321  * provided by the architecture for a given node by using the end of the
6322  * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
6323  * zones within a node are in order of monotonic increases memory addresses
6324  */
6325 static void __init adjust_zone_range_for_zone_movable(int nid,
6326 					unsigned long zone_type,
6327 					unsigned long node_start_pfn,
6328 					unsigned long node_end_pfn,
6329 					unsigned long *zone_start_pfn,
6330 					unsigned long *zone_end_pfn)
6331 {
6332 	/* Only adjust if ZONE_MOVABLE is on this node */
6333 	if (zone_movable_pfn[nid]) {
6334 		/* Size ZONE_MOVABLE */
6335 		if (zone_type == ZONE_MOVABLE) {
6336 			*zone_start_pfn = zone_movable_pfn[nid];
6337 			*zone_end_pfn = min(node_end_pfn,
6338 				arch_zone_highest_possible_pfn[movable_zone]);
6339 
6340 		/* Adjust for ZONE_MOVABLE starting within this range */
6341 		} else if (!mirrored_kernelcore &&
6342 			*zone_start_pfn < zone_movable_pfn[nid] &&
6343 			*zone_end_pfn > zone_movable_pfn[nid]) {
6344 			*zone_end_pfn = zone_movable_pfn[nid];
6345 
6346 		/* Check if this whole range is within ZONE_MOVABLE */
6347 		} else if (*zone_start_pfn >= zone_movable_pfn[nid])
6348 			*zone_start_pfn = *zone_end_pfn;
6349 	}
6350 }
6351 
6352 /*
6353  * Return the number of pages a zone spans in a node, including holes
6354  * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
6355  */
6356 static unsigned long __init zone_spanned_pages_in_node(int nid,
6357 					unsigned long zone_type,
6358 					unsigned long node_start_pfn,
6359 					unsigned long node_end_pfn,
6360 					unsigned long *zone_start_pfn,
6361 					unsigned long *zone_end_pfn,
6362 					unsigned long *ignored)
6363 {
6364 	unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
6365 	unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
6366 	/* When hotadd a new node from cpu_up(), the node should be empty */
6367 	if (!node_start_pfn && !node_end_pfn)
6368 		return 0;
6369 
6370 	/* Get the start and end of the zone */
6371 	*zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
6372 	*zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
6373 	adjust_zone_range_for_zone_movable(nid, zone_type,
6374 				node_start_pfn, node_end_pfn,
6375 				zone_start_pfn, zone_end_pfn);
6376 
6377 	/* Check that this node has pages within the zone's required range */
6378 	if (*zone_end_pfn < node_start_pfn || *zone_start_pfn > node_end_pfn)
6379 		return 0;
6380 
6381 	/* Move the zone boundaries inside the node if necessary */
6382 	*zone_end_pfn = min(*zone_end_pfn, node_end_pfn);
6383 	*zone_start_pfn = max(*zone_start_pfn, node_start_pfn);
6384 
6385 	/* Return the spanned pages */
6386 	return *zone_end_pfn - *zone_start_pfn;
6387 }
6388 
6389 /*
6390  * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
6391  * then all holes in the requested range will be accounted for.
6392  */
6393 unsigned long __init __absent_pages_in_range(int nid,
6394 				unsigned long range_start_pfn,
6395 				unsigned long range_end_pfn)
6396 {
6397 	unsigned long nr_absent = range_end_pfn - range_start_pfn;
6398 	unsigned long start_pfn, end_pfn;
6399 	int i;
6400 
6401 	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
6402 		start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
6403 		end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
6404 		nr_absent -= end_pfn - start_pfn;
6405 	}
6406 	return nr_absent;
6407 }
6408 
6409 /**
6410  * absent_pages_in_range - Return number of page frames in holes within a range
6411  * @start_pfn: The start PFN to start searching for holes
6412  * @end_pfn: The end PFN to stop searching for holes
6413  *
6414  * Return: the number of pages frames in memory holes within a range.
6415  */
6416 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
6417 							unsigned long end_pfn)
6418 {
6419 	return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
6420 }
6421 
6422 /* Return the number of page frames in holes in a zone on a node */
6423 static unsigned long __init zone_absent_pages_in_node(int nid,
6424 					unsigned long zone_type,
6425 					unsigned long node_start_pfn,
6426 					unsigned long node_end_pfn,
6427 					unsigned long *ignored)
6428 {
6429 	unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
6430 	unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
6431 	unsigned long zone_start_pfn, zone_end_pfn;
6432 	unsigned long nr_absent;
6433 
6434 	/* When hotadd a new node from cpu_up(), the node should be empty */
6435 	if (!node_start_pfn && !node_end_pfn)
6436 		return 0;
6437 
6438 	zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
6439 	zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
6440 
6441 	adjust_zone_range_for_zone_movable(nid, zone_type,
6442 			node_start_pfn, node_end_pfn,
6443 			&zone_start_pfn, &zone_end_pfn);
6444 	nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
6445 
6446 	/*
6447 	 * ZONE_MOVABLE handling.
6448 	 * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
6449 	 * and vice versa.
6450 	 */
6451 	if (mirrored_kernelcore && zone_movable_pfn[nid]) {
6452 		unsigned long start_pfn, end_pfn;
6453 		struct memblock_region *r;
6454 
6455 		for_each_memblock(memory, r) {
6456 			start_pfn = clamp(memblock_region_memory_base_pfn(r),
6457 					  zone_start_pfn, zone_end_pfn);
6458 			end_pfn = clamp(memblock_region_memory_end_pfn(r),
6459 					zone_start_pfn, zone_end_pfn);
6460 
6461 			if (zone_type == ZONE_MOVABLE &&
6462 			    memblock_is_mirror(r))
6463 				nr_absent += end_pfn - start_pfn;
6464 
6465 			if (zone_type == ZONE_NORMAL &&
6466 			    !memblock_is_mirror(r))
6467 				nr_absent += end_pfn - start_pfn;
6468 		}
6469 	}
6470 
6471 	return nr_absent;
6472 }
6473 
6474 #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6475 static inline unsigned long __init zone_spanned_pages_in_node(int nid,
6476 					unsigned long zone_type,
6477 					unsigned long node_start_pfn,
6478 					unsigned long node_end_pfn,
6479 					unsigned long *zone_start_pfn,
6480 					unsigned long *zone_end_pfn,
6481 					unsigned long *zones_size)
6482 {
6483 	unsigned int zone;
6484 
6485 	*zone_start_pfn = node_start_pfn;
6486 	for (zone = 0; zone < zone_type; zone++)
6487 		*zone_start_pfn += zones_size[zone];
6488 
6489 	*zone_end_pfn = *zone_start_pfn + zones_size[zone_type];
6490 
6491 	return zones_size[zone_type];
6492 }
6493 
6494 static inline unsigned long __init zone_absent_pages_in_node(int nid,
6495 						unsigned long zone_type,
6496 						unsigned long node_start_pfn,
6497 						unsigned long node_end_pfn,
6498 						unsigned long *zholes_size)
6499 {
6500 	if (!zholes_size)
6501 		return 0;
6502 
6503 	return zholes_size[zone_type];
6504 }
6505 
6506 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6507 
6508 static void __init calculate_node_totalpages(struct pglist_data *pgdat,
6509 						unsigned long node_start_pfn,
6510 						unsigned long node_end_pfn,
6511 						unsigned long *zones_size,
6512 						unsigned long *zholes_size)
6513 {
6514 	unsigned long realtotalpages = 0, totalpages = 0;
6515 	enum zone_type i;
6516 
6517 	for (i = 0; i < MAX_NR_ZONES; i++) {
6518 		struct zone *zone = pgdat->node_zones + i;
6519 		unsigned long zone_start_pfn, zone_end_pfn;
6520 		unsigned long size, real_size;
6521 
6522 		size = zone_spanned_pages_in_node(pgdat->node_id, i,
6523 						  node_start_pfn,
6524 						  node_end_pfn,
6525 						  &zone_start_pfn,
6526 						  &zone_end_pfn,
6527 						  zones_size);
6528 		real_size = size - zone_absent_pages_in_node(pgdat->node_id, i,
6529 						  node_start_pfn, node_end_pfn,
6530 						  zholes_size);
6531 		if (size)
6532 			zone->zone_start_pfn = zone_start_pfn;
6533 		else
6534 			zone->zone_start_pfn = 0;
6535 		zone->spanned_pages = size;
6536 		zone->present_pages = real_size;
6537 
6538 		totalpages += size;
6539 		realtotalpages += real_size;
6540 	}
6541 
6542 	pgdat->node_spanned_pages = totalpages;
6543 	pgdat->node_present_pages = realtotalpages;
6544 	printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
6545 							realtotalpages);
6546 }
6547 
6548 #ifndef CONFIG_SPARSEMEM
6549 /*
6550  * Calculate the size of the zone->blockflags rounded to an unsigned long
6551  * Start by making sure zonesize is a multiple of pageblock_order by rounding
6552  * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
6553  * round what is now in bits to nearest long in bits, then return it in
6554  * bytes.
6555  */
6556 static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
6557 {
6558 	unsigned long usemapsize;
6559 
6560 	zonesize += zone_start_pfn & (pageblock_nr_pages-1);
6561 	usemapsize = roundup(zonesize, pageblock_nr_pages);
6562 	usemapsize = usemapsize >> pageblock_order;
6563 	usemapsize *= NR_PAGEBLOCK_BITS;
6564 	usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
6565 
6566 	return usemapsize / 8;
6567 }
6568 
6569 static void __ref setup_usemap(struct pglist_data *pgdat,
6570 				struct zone *zone,
6571 				unsigned long zone_start_pfn,
6572 				unsigned long zonesize)
6573 {
6574 	unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
6575 	zone->pageblock_flags = NULL;
6576 	if (usemapsize) {
6577 		zone->pageblock_flags =
6578 			memblock_alloc_node(usemapsize, SMP_CACHE_BYTES,
6579 					    pgdat->node_id);
6580 		if (!zone->pageblock_flags)
6581 			panic("Failed to allocate %ld bytes for zone %s pageblock flags on node %d\n",
6582 			      usemapsize, zone->name, pgdat->node_id);
6583 	}
6584 }
6585 #else
6586 static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
6587 				unsigned long zone_start_pfn, unsigned long zonesize) {}
6588 #endif /* CONFIG_SPARSEMEM */
6589 
6590 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
6591 
6592 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
6593 void __init set_pageblock_order(void)
6594 {
6595 	unsigned int order;
6596 
6597 	/* Check that pageblock_nr_pages has not already been setup */
6598 	if (pageblock_order)
6599 		return;
6600 
6601 	if (HPAGE_SHIFT > PAGE_SHIFT)
6602 		order = HUGETLB_PAGE_ORDER;
6603 	else
6604 		order = MAX_ORDER - 1;
6605 
6606 	/*
6607 	 * Assume the largest contiguous order of interest is a huge page.
6608 	 * This value may be variable depending on boot parameters on IA64 and
6609 	 * powerpc.
6610 	 */
6611 	pageblock_order = order;
6612 }
6613 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
6614 
6615 /*
6616  * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
6617  * is unused as pageblock_order is set at compile-time. See
6618  * include/linux/pageblock-flags.h for the values of pageblock_order based on
6619  * the kernel config
6620  */
6621 void __init set_pageblock_order(void)
6622 {
6623 }
6624 
6625 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
6626 
6627 static unsigned long __init calc_memmap_size(unsigned long spanned_pages,
6628 						unsigned long present_pages)
6629 {
6630 	unsigned long pages = spanned_pages;
6631 
6632 	/*
6633 	 * Provide a more accurate estimation if there are holes within
6634 	 * the zone and SPARSEMEM is in use. If there are holes within the
6635 	 * zone, each populated memory region may cost us one or two extra
6636 	 * memmap pages due to alignment because memmap pages for each
6637 	 * populated regions may not be naturally aligned on page boundary.
6638 	 * So the (present_pages >> 4) heuristic is a tradeoff for that.
6639 	 */
6640 	if (spanned_pages > present_pages + (present_pages >> 4) &&
6641 	    IS_ENABLED(CONFIG_SPARSEMEM))
6642 		pages = present_pages;
6643 
6644 	return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
6645 }
6646 
6647 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6648 static void pgdat_init_split_queue(struct pglist_data *pgdat)
6649 {
6650 	struct deferred_split *ds_queue = &pgdat->deferred_split_queue;
6651 
6652 	spin_lock_init(&ds_queue->split_queue_lock);
6653 	INIT_LIST_HEAD(&ds_queue->split_queue);
6654 	ds_queue->split_queue_len = 0;
6655 }
6656 #else
6657 static void pgdat_init_split_queue(struct pglist_data *pgdat) {}
6658 #endif
6659 
6660 #ifdef CONFIG_COMPACTION
6661 static void pgdat_init_kcompactd(struct pglist_data *pgdat)
6662 {
6663 	init_waitqueue_head(&pgdat->kcompactd_wait);
6664 }
6665 #else
6666 static void pgdat_init_kcompactd(struct pglist_data *pgdat) {}
6667 #endif
6668 
6669 static void __meminit pgdat_init_internals(struct pglist_data *pgdat)
6670 {
6671 	pgdat_resize_init(pgdat);
6672 
6673 	pgdat_init_split_queue(pgdat);
6674 	pgdat_init_kcompactd(pgdat);
6675 
6676 	init_waitqueue_head(&pgdat->kswapd_wait);
6677 	init_waitqueue_head(&pgdat->pfmemalloc_wait);
6678 
6679 	pgdat_page_ext_init(pgdat);
6680 	spin_lock_init(&pgdat->lru_lock);
6681 	lruvec_init(node_lruvec(pgdat));
6682 }
6683 
6684 static void __meminit zone_init_internals(struct zone *zone, enum zone_type idx, int nid,
6685 							unsigned long remaining_pages)
6686 {
6687 	atomic_long_set(&zone->managed_pages, remaining_pages);
6688 	zone_set_nid(zone, nid);
6689 	zone->name = zone_names[idx];
6690 	zone->zone_pgdat = NODE_DATA(nid);
6691 	spin_lock_init(&zone->lock);
6692 	zone_seqlock_init(zone);
6693 	zone_pcp_init(zone);
6694 }
6695 
6696 /*
6697  * Set up the zone data structures
6698  * - init pgdat internals
6699  * - init all zones belonging to this node
6700  *
6701  * NOTE: this function is only called during memory hotplug
6702  */
6703 #ifdef CONFIG_MEMORY_HOTPLUG
6704 void __ref free_area_init_core_hotplug(int nid)
6705 {
6706 	enum zone_type z;
6707 	pg_data_t *pgdat = NODE_DATA(nid);
6708 
6709 	pgdat_init_internals(pgdat);
6710 	for (z = 0; z < MAX_NR_ZONES; z++)
6711 		zone_init_internals(&pgdat->node_zones[z], z, nid, 0);
6712 }
6713 #endif
6714 
6715 /*
6716  * Set up the zone data structures:
6717  *   - mark all pages reserved
6718  *   - mark all memory queues empty
6719  *   - clear the memory bitmaps
6720  *
6721  * NOTE: pgdat should get zeroed by caller.
6722  * NOTE: this function is only called during early init.
6723  */
6724 static void __init free_area_init_core(struct pglist_data *pgdat)
6725 {
6726 	enum zone_type j;
6727 	int nid = pgdat->node_id;
6728 
6729 	pgdat_init_internals(pgdat);
6730 	pgdat->per_cpu_nodestats = &boot_nodestats;
6731 
6732 	for (j = 0; j < MAX_NR_ZONES; j++) {
6733 		struct zone *zone = pgdat->node_zones + j;
6734 		unsigned long size, freesize, memmap_pages;
6735 		unsigned long zone_start_pfn = zone->zone_start_pfn;
6736 
6737 		size = zone->spanned_pages;
6738 		freesize = zone->present_pages;
6739 
6740 		/*
6741 		 * Adjust freesize so that it accounts for how much memory
6742 		 * is used by this zone for memmap. This affects the watermark
6743 		 * and per-cpu initialisations
6744 		 */
6745 		memmap_pages = calc_memmap_size(size, freesize);
6746 		if (!is_highmem_idx(j)) {
6747 			if (freesize >= memmap_pages) {
6748 				freesize -= memmap_pages;
6749 				if (memmap_pages)
6750 					printk(KERN_DEBUG
6751 					       "  %s zone: %lu pages used for memmap\n",
6752 					       zone_names[j], memmap_pages);
6753 			} else
6754 				pr_warn("  %s zone: %lu pages exceeds freesize %lu\n",
6755 					zone_names[j], memmap_pages, freesize);
6756 		}
6757 
6758 		/* Account for reserved pages */
6759 		if (j == 0 && freesize > dma_reserve) {
6760 			freesize -= dma_reserve;
6761 			printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
6762 					zone_names[0], dma_reserve);
6763 		}
6764 
6765 		if (!is_highmem_idx(j))
6766 			nr_kernel_pages += freesize;
6767 		/* Charge for highmem memmap if there are enough kernel pages */
6768 		else if (nr_kernel_pages > memmap_pages * 2)
6769 			nr_kernel_pages -= memmap_pages;
6770 		nr_all_pages += freesize;
6771 
6772 		/*
6773 		 * Set an approximate value for lowmem here, it will be adjusted
6774 		 * when the bootmem allocator frees pages into the buddy system.
6775 		 * And all highmem pages will be managed by the buddy system.
6776 		 */
6777 		zone_init_internals(zone, j, nid, freesize);
6778 
6779 		if (!size)
6780 			continue;
6781 
6782 		set_pageblock_order();
6783 		setup_usemap(pgdat, zone, zone_start_pfn, size);
6784 		init_currently_empty_zone(zone, zone_start_pfn, size);
6785 		memmap_init(size, nid, j, zone_start_pfn);
6786 	}
6787 }
6788 
6789 #ifdef CONFIG_FLAT_NODE_MEM_MAP
6790 static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
6791 {
6792 	unsigned long __maybe_unused start = 0;
6793 	unsigned long __maybe_unused offset = 0;
6794 
6795 	/* Skip empty nodes */
6796 	if (!pgdat->node_spanned_pages)
6797 		return;
6798 
6799 	start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
6800 	offset = pgdat->node_start_pfn - start;
6801 	/* ia64 gets its own node_mem_map, before this, without bootmem */
6802 	if (!pgdat->node_mem_map) {
6803 		unsigned long size, end;
6804 		struct page *map;
6805 
6806 		/*
6807 		 * The zone's endpoints aren't required to be MAX_ORDER
6808 		 * aligned but the node_mem_map endpoints must be in order
6809 		 * for the buddy allocator to function correctly.
6810 		 */
6811 		end = pgdat_end_pfn(pgdat);
6812 		end = ALIGN(end, MAX_ORDER_NR_PAGES);
6813 		size =  (end - start) * sizeof(struct page);
6814 		map = memblock_alloc_node(size, SMP_CACHE_BYTES,
6815 					  pgdat->node_id);
6816 		if (!map)
6817 			panic("Failed to allocate %ld bytes for node %d memory map\n",
6818 			      size, pgdat->node_id);
6819 		pgdat->node_mem_map = map + offset;
6820 	}
6821 	pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
6822 				__func__, pgdat->node_id, (unsigned long)pgdat,
6823 				(unsigned long)pgdat->node_mem_map);
6824 #ifndef CONFIG_NEED_MULTIPLE_NODES
6825 	/*
6826 	 * With no DISCONTIG, the global mem_map is just set as node 0's
6827 	 */
6828 	if (pgdat == NODE_DATA(0)) {
6829 		mem_map = NODE_DATA(0)->node_mem_map;
6830 #if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM)
6831 		if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
6832 			mem_map -= offset;
6833 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6834 	}
6835 #endif
6836 }
6837 #else
6838 static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { }
6839 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
6840 
6841 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
6842 static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
6843 {
6844 	pgdat->first_deferred_pfn = ULONG_MAX;
6845 }
6846 #else
6847 static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
6848 #endif
6849 
6850 void __init free_area_init_node(int nid, unsigned long *zones_size,
6851 				   unsigned long node_start_pfn,
6852 				   unsigned long *zholes_size)
6853 {
6854 	pg_data_t *pgdat = NODE_DATA(nid);
6855 	unsigned long start_pfn = 0;
6856 	unsigned long end_pfn = 0;
6857 
6858 	/* pg_data_t should be reset to zero when it's allocated */
6859 	WARN_ON(pgdat->nr_zones || pgdat->kswapd_classzone_idx);
6860 
6861 	pgdat->node_id = nid;
6862 	pgdat->node_start_pfn = node_start_pfn;
6863 	pgdat->per_cpu_nodestats = NULL;
6864 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
6865 	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
6866 	pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
6867 		(u64)start_pfn << PAGE_SHIFT,
6868 		end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
6869 #else
6870 	start_pfn = node_start_pfn;
6871 #endif
6872 	calculate_node_totalpages(pgdat, start_pfn, end_pfn,
6873 				  zones_size, zholes_size);
6874 
6875 	alloc_node_mem_map(pgdat);
6876 	pgdat_set_deferred_range(pgdat);
6877 
6878 	free_area_init_core(pgdat);
6879 }
6880 
6881 #if !defined(CONFIG_FLAT_NODE_MEM_MAP)
6882 /*
6883  * Zero all valid struct pages in range [spfn, epfn), return number of struct
6884  * pages zeroed
6885  */
6886 static u64 zero_pfn_range(unsigned long spfn, unsigned long epfn)
6887 {
6888 	unsigned long pfn;
6889 	u64 pgcnt = 0;
6890 
6891 	for (pfn = spfn; pfn < epfn; pfn++) {
6892 		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
6893 			pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
6894 				+ pageblock_nr_pages - 1;
6895 			continue;
6896 		}
6897 		mm_zero_struct_page(pfn_to_page(pfn));
6898 		pgcnt++;
6899 	}
6900 
6901 	return pgcnt;
6902 }
6903 
6904 /*
6905  * Only struct pages that are backed by physical memory are zeroed and
6906  * initialized by going through __init_single_page(). But, there are some
6907  * struct pages which are reserved in memblock allocator and their fields
6908  * may be accessed (for example page_to_pfn() on some configuration accesses
6909  * flags). We must explicitly zero those struct pages.
6910  *
6911  * This function also addresses a similar issue where struct pages are left
6912  * uninitialized because the physical address range is not covered by
6913  * memblock.memory or memblock.reserved. That could happen when memblock
6914  * layout is manually configured via memmap=.
6915  */
6916 void __init zero_resv_unavail(void)
6917 {
6918 	phys_addr_t start, end;
6919 	u64 i, pgcnt;
6920 	phys_addr_t next = 0;
6921 
6922 	/*
6923 	 * Loop through unavailable ranges not covered by memblock.memory.
6924 	 */
6925 	pgcnt = 0;
6926 	for_each_mem_range(i, &memblock.memory, NULL,
6927 			NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) {
6928 		if (next < start)
6929 			pgcnt += zero_pfn_range(PFN_DOWN(next), PFN_UP(start));
6930 		next = end;
6931 	}
6932 	pgcnt += zero_pfn_range(PFN_DOWN(next), max_pfn);
6933 
6934 	/*
6935 	 * Struct pages that do not have backing memory. This could be because
6936 	 * firmware is using some of this memory, or for some other reasons.
6937 	 */
6938 	if (pgcnt)
6939 		pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt);
6940 }
6941 #endif /* !CONFIG_FLAT_NODE_MEM_MAP */
6942 
6943 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
6944 
6945 #if MAX_NUMNODES > 1
6946 /*
6947  * Figure out the number of possible node ids.
6948  */
6949 void __init setup_nr_node_ids(void)
6950 {
6951 	unsigned int highest;
6952 
6953 	highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES);
6954 	nr_node_ids = highest + 1;
6955 }
6956 #endif
6957 
6958 /**
6959  * node_map_pfn_alignment - determine the maximum internode alignment
6960  *
6961  * This function should be called after node map is populated and sorted.
6962  * It calculates the maximum power of two alignment which can distinguish
6963  * all the nodes.
6964  *
6965  * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
6966  * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)).  If the
6967  * nodes are shifted by 256MiB, 256MiB.  Note that if only the last node is
6968  * shifted, 1GiB is enough and this function will indicate so.
6969  *
6970  * This is used to test whether pfn -> nid mapping of the chosen memory
6971  * model has fine enough granularity to avoid incorrect mapping for the
6972  * populated node map.
6973  *
6974  * Return: the determined alignment in pfn's.  0 if there is no alignment
6975  * requirement (single node).
6976  */
6977 unsigned long __init node_map_pfn_alignment(void)
6978 {
6979 	unsigned long accl_mask = 0, last_end = 0;
6980 	unsigned long start, end, mask;
6981 	int last_nid = NUMA_NO_NODE;
6982 	int i, nid;
6983 
6984 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
6985 		if (!start || last_nid < 0 || last_nid == nid) {
6986 			last_nid = nid;
6987 			last_end = end;
6988 			continue;
6989 		}
6990 
6991 		/*
6992 		 * Start with a mask granular enough to pin-point to the
6993 		 * start pfn and tick off bits one-by-one until it becomes
6994 		 * too coarse to separate the current node from the last.
6995 		 */
6996 		mask = ~((1 << __ffs(start)) - 1);
6997 		while (mask && last_end <= (start & (mask << 1)))
6998 			mask <<= 1;
6999 
7000 		/* accumulate all internode masks */
7001 		accl_mask |= mask;
7002 	}
7003 
7004 	/* convert mask to number of pages */
7005 	return ~accl_mask + 1;
7006 }
7007 
7008 /* Find the lowest pfn for a node */
7009 static unsigned long __init find_min_pfn_for_node(int nid)
7010 {
7011 	unsigned long min_pfn = ULONG_MAX;
7012 	unsigned long start_pfn;
7013 	int i;
7014 
7015 	for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
7016 		min_pfn = min(min_pfn, start_pfn);
7017 
7018 	if (min_pfn == ULONG_MAX) {
7019 		pr_warn("Could not find start_pfn for node %d\n", nid);
7020 		return 0;
7021 	}
7022 
7023 	return min_pfn;
7024 }
7025 
7026 /**
7027  * find_min_pfn_with_active_regions - Find the minimum PFN registered
7028  *
7029  * Return: the minimum PFN based on information provided via
7030  * memblock_set_node().
7031  */
7032 unsigned long __init find_min_pfn_with_active_regions(void)
7033 {
7034 	return find_min_pfn_for_node(MAX_NUMNODES);
7035 }
7036 
7037 /*
7038  * early_calculate_totalpages()
7039  * Sum pages in active regions for movable zone.
7040  * Populate N_MEMORY for calculating usable_nodes.
7041  */
7042 static unsigned long __init early_calculate_totalpages(void)
7043 {
7044 	unsigned long totalpages = 0;
7045 	unsigned long start_pfn, end_pfn;
7046 	int i, nid;
7047 
7048 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
7049 		unsigned long pages = end_pfn - start_pfn;
7050 
7051 		totalpages += pages;
7052 		if (pages)
7053 			node_set_state(nid, N_MEMORY);
7054 	}
7055 	return totalpages;
7056 }
7057 
7058 /*
7059  * Find the PFN the Movable zone begins in each node. Kernel memory
7060  * is spread evenly between nodes as long as the nodes have enough
7061  * memory. When they don't, some nodes will have more kernelcore than
7062  * others
7063  */
7064 static void __init find_zone_movable_pfns_for_nodes(void)
7065 {
7066 	int i, nid;
7067 	unsigned long usable_startpfn;
7068 	unsigned long kernelcore_node, kernelcore_remaining;
7069 	/* save the state before borrow the nodemask */
7070 	nodemask_t saved_node_state = node_states[N_MEMORY];
7071 	unsigned long totalpages = early_calculate_totalpages();
7072 	int usable_nodes = nodes_weight(node_states[N_MEMORY]);
7073 	struct memblock_region *r;
7074 
7075 	/* Need to find movable_zone earlier when movable_node is specified. */
7076 	find_usable_zone_for_movable();
7077 
7078 	/*
7079 	 * If movable_node is specified, ignore kernelcore and movablecore
7080 	 * options.
7081 	 */
7082 	if (movable_node_is_enabled()) {
7083 		for_each_memblock(memory, r) {
7084 			if (!memblock_is_hotpluggable(r))
7085 				continue;
7086 
7087 			nid = r->nid;
7088 
7089 			usable_startpfn = PFN_DOWN(r->base);
7090 			zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
7091 				min(usable_startpfn, zone_movable_pfn[nid]) :
7092 				usable_startpfn;
7093 		}
7094 
7095 		goto out2;
7096 	}
7097 
7098 	/*
7099 	 * If kernelcore=mirror is specified, ignore movablecore option
7100 	 */
7101 	if (mirrored_kernelcore) {
7102 		bool mem_below_4gb_not_mirrored = false;
7103 
7104 		for_each_memblock(memory, r) {
7105 			if (memblock_is_mirror(r))
7106 				continue;
7107 
7108 			nid = r->nid;
7109 
7110 			usable_startpfn = memblock_region_memory_base_pfn(r);
7111 
7112 			if (usable_startpfn < 0x100000) {
7113 				mem_below_4gb_not_mirrored = true;
7114 				continue;
7115 			}
7116 
7117 			zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
7118 				min(usable_startpfn, zone_movable_pfn[nid]) :
7119 				usable_startpfn;
7120 		}
7121 
7122 		if (mem_below_4gb_not_mirrored)
7123 			pr_warn("This configuration results in unmirrored kernel memory.");
7124 
7125 		goto out2;
7126 	}
7127 
7128 	/*
7129 	 * If kernelcore=nn% or movablecore=nn% was specified, calculate the
7130 	 * amount of necessary memory.
7131 	 */
7132 	if (required_kernelcore_percent)
7133 		required_kernelcore = (totalpages * 100 * required_kernelcore_percent) /
7134 				       10000UL;
7135 	if (required_movablecore_percent)
7136 		required_movablecore = (totalpages * 100 * required_movablecore_percent) /
7137 					10000UL;
7138 
7139 	/*
7140 	 * If movablecore= was specified, calculate what size of
7141 	 * kernelcore that corresponds so that memory usable for
7142 	 * any allocation type is evenly spread. If both kernelcore
7143 	 * and movablecore are specified, then the value of kernelcore
7144 	 * will be used for required_kernelcore if it's greater than
7145 	 * what movablecore would have allowed.
7146 	 */
7147 	if (required_movablecore) {
7148 		unsigned long corepages;
7149 
7150 		/*
7151 		 * Round-up so that ZONE_MOVABLE is at least as large as what
7152 		 * was requested by the user
7153 		 */
7154 		required_movablecore =
7155 			roundup(required_movablecore, MAX_ORDER_NR_PAGES);
7156 		required_movablecore = min(totalpages, required_movablecore);
7157 		corepages = totalpages - required_movablecore;
7158 
7159 		required_kernelcore = max(required_kernelcore, corepages);
7160 	}
7161 
7162 	/*
7163 	 * If kernelcore was not specified or kernelcore size is larger
7164 	 * than totalpages, there is no ZONE_MOVABLE.
7165 	 */
7166 	if (!required_kernelcore || required_kernelcore >= totalpages)
7167 		goto out;
7168 
7169 	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
7170 	usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
7171 
7172 restart:
7173 	/* Spread kernelcore memory as evenly as possible throughout nodes */
7174 	kernelcore_node = required_kernelcore / usable_nodes;
7175 	for_each_node_state(nid, N_MEMORY) {
7176 		unsigned long start_pfn, end_pfn;
7177 
7178 		/*
7179 		 * Recalculate kernelcore_node if the division per node
7180 		 * now exceeds what is necessary to satisfy the requested
7181 		 * amount of memory for the kernel
7182 		 */
7183 		if (required_kernelcore < kernelcore_node)
7184 			kernelcore_node = required_kernelcore / usable_nodes;
7185 
7186 		/*
7187 		 * As the map is walked, we track how much memory is usable
7188 		 * by the kernel using kernelcore_remaining. When it is
7189 		 * 0, the rest of the node is usable by ZONE_MOVABLE
7190 		 */
7191 		kernelcore_remaining = kernelcore_node;
7192 
7193 		/* Go through each range of PFNs within this node */
7194 		for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
7195 			unsigned long size_pages;
7196 
7197 			start_pfn = max(start_pfn, zone_movable_pfn[nid]);
7198 			if (start_pfn >= end_pfn)
7199 				continue;
7200 
7201 			/* Account for what is only usable for kernelcore */
7202 			if (start_pfn < usable_startpfn) {
7203 				unsigned long kernel_pages;
7204 				kernel_pages = min(end_pfn, usable_startpfn)
7205 								- start_pfn;
7206 
7207 				kernelcore_remaining -= min(kernel_pages,
7208 							kernelcore_remaining);
7209 				required_kernelcore -= min(kernel_pages,
7210 							required_kernelcore);
7211 
7212 				/* Continue if range is now fully accounted */
7213 				if (end_pfn <= usable_startpfn) {
7214 
7215 					/*
7216 					 * Push zone_movable_pfn to the end so
7217 					 * that if we have to rebalance
7218 					 * kernelcore across nodes, we will
7219 					 * not double account here
7220 					 */
7221 					zone_movable_pfn[nid] = end_pfn;
7222 					continue;
7223 				}
7224 				start_pfn = usable_startpfn;
7225 			}
7226 
7227 			/*
7228 			 * The usable PFN range for ZONE_MOVABLE is from
7229 			 * start_pfn->end_pfn. Calculate size_pages as the
7230 			 * number of pages used as kernelcore
7231 			 */
7232 			size_pages = end_pfn - start_pfn;
7233 			if (size_pages > kernelcore_remaining)
7234 				size_pages = kernelcore_remaining;
7235 			zone_movable_pfn[nid] = start_pfn + size_pages;
7236 
7237 			/*
7238 			 * Some kernelcore has been met, update counts and
7239 			 * break if the kernelcore for this node has been
7240 			 * satisfied
7241 			 */
7242 			required_kernelcore -= min(required_kernelcore,
7243 								size_pages);
7244 			kernelcore_remaining -= size_pages;
7245 			if (!kernelcore_remaining)
7246 				break;
7247 		}
7248 	}
7249 
7250 	/*
7251 	 * If there is still required_kernelcore, we do another pass with one
7252 	 * less node in the count. This will push zone_movable_pfn[nid] further
7253 	 * along on the nodes that still have memory until kernelcore is
7254 	 * satisfied
7255 	 */
7256 	usable_nodes--;
7257 	if (usable_nodes && required_kernelcore > usable_nodes)
7258 		goto restart;
7259 
7260 out2:
7261 	/* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
7262 	for (nid = 0; nid < MAX_NUMNODES; nid++)
7263 		zone_movable_pfn[nid] =
7264 			roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
7265 
7266 out:
7267 	/* restore the node_state */
7268 	node_states[N_MEMORY] = saved_node_state;
7269 }
7270 
7271 /* Any regular or high memory on that node ? */
7272 static void check_for_memory(pg_data_t *pgdat, int nid)
7273 {
7274 	enum zone_type zone_type;
7275 
7276 	for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
7277 		struct zone *zone = &pgdat->node_zones[zone_type];
7278 		if (populated_zone(zone)) {
7279 			if (IS_ENABLED(CONFIG_HIGHMEM))
7280 				node_set_state(nid, N_HIGH_MEMORY);
7281 			if (zone_type <= ZONE_NORMAL)
7282 				node_set_state(nid, N_NORMAL_MEMORY);
7283 			break;
7284 		}
7285 	}
7286 }
7287 
7288 /**
7289  * free_area_init_nodes - Initialise all pg_data_t and zone data
7290  * @max_zone_pfn: an array of max PFNs for each zone
7291  *
7292  * This will call free_area_init_node() for each active node in the system.
7293  * Using the page ranges provided by memblock_set_node(), the size of each
7294  * zone in each node and their holes is calculated. If the maximum PFN
7295  * between two adjacent zones match, it is assumed that the zone is empty.
7296  * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
7297  * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
7298  * starts where the previous one ended. For example, ZONE_DMA32 starts
7299  * at arch_max_dma_pfn.
7300  */
7301 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
7302 {
7303 	unsigned long start_pfn, end_pfn;
7304 	int i, nid;
7305 
7306 	/* Record where the zone boundaries are */
7307 	memset(arch_zone_lowest_possible_pfn, 0,
7308 				sizeof(arch_zone_lowest_possible_pfn));
7309 	memset(arch_zone_highest_possible_pfn, 0,
7310 				sizeof(arch_zone_highest_possible_pfn));
7311 
7312 	start_pfn = find_min_pfn_with_active_regions();
7313 
7314 	for (i = 0; i < MAX_NR_ZONES; i++) {
7315 		if (i == ZONE_MOVABLE)
7316 			continue;
7317 
7318 		end_pfn = max(max_zone_pfn[i], start_pfn);
7319 		arch_zone_lowest_possible_pfn[i] = start_pfn;
7320 		arch_zone_highest_possible_pfn[i] = end_pfn;
7321 
7322 		start_pfn = end_pfn;
7323 	}
7324 
7325 	/* Find the PFNs that ZONE_MOVABLE begins at in each node */
7326 	memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
7327 	find_zone_movable_pfns_for_nodes();
7328 
7329 	/* Print out the zone ranges */
7330 	pr_info("Zone ranges:\n");
7331 	for (i = 0; i < MAX_NR_ZONES; i++) {
7332 		if (i == ZONE_MOVABLE)
7333 			continue;
7334 		pr_info("  %-8s ", zone_names[i]);
7335 		if (arch_zone_lowest_possible_pfn[i] ==
7336 				arch_zone_highest_possible_pfn[i])
7337 			pr_cont("empty\n");
7338 		else
7339 			pr_cont("[mem %#018Lx-%#018Lx]\n",
7340 				(u64)arch_zone_lowest_possible_pfn[i]
7341 					<< PAGE_SHIFT,
7342 				((u64)arch_zone_highest_possible_pfn[i]
7343 					<< PAGE_SHIFT) - 1);
7344 	}
7345 
7346 	/* Print out the PFNs ZONE_MOVABLE begins at in each node */
7347 	pr_info("Movable zone start for each node\n");
7348 	for (i = 0; i < MAX_NUMNODES; i++) {
7349 		if (zone_movable_pfn[i])
7350 			pr_info("  Node %d: %#018Lx\n", i,
7351 			       (u64)zone_movable_pfn[i] << PAGE_SHIFT);
7352 	}
7353 
7354 	/*
7355 	 * Print out the early node map, and initialize the
7356 	 * subsection-map relative to active online memory ranges to
7357 	 * enable future "sub-section" extensions of the memory map.
7358 	 */
7359 	pr_info("Early memory node ranges\n");
7360 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
7361 		pr_info("  node %3d: [mem %#018Lx-%#018Lx]\n", nid,
7362 			(u64)start_pfn << PAGE_SHIFT,
7363 			((u64)end_pfn << PAGE_SHIFT) - 1);
7364 		subsection_map_init(start_pfn, end_pfn - start_pfn);
7365 	}
7366 
7367 	/* Initialise every node */
7368 	mminit_verify_pageflags_layout();
7369 	setup_nr_node_ids();
7370 	zero_resv_unavail();
7371 	for_each_online_node(nid) {
7372 		pg_data_t *pgdat = NODE_DATA(nid);
7373 		free_area_init_node(nid, NULL,
7374 				find_min_pfn_for_node(nid), NULL);
7375 
7376 		/* Any memory on that node */
7377 		if (pgdat->node_present_pages)
7378 			node_set_state(nid, N_MEMORY);
7379 		check_for_memory(pgdat, nid);
7380 	}
7381 }
7382 
7383 static int __init cmdline_parse_core(char *p, unsigned long *core,
7384 				     unsigned long *percent)
7385 {
7386 	unsigned long long coremem;
7387 	char *endptr;
7388 
7389 	if (!p)
7390 		return -EINVAL;
7391 
7392 	/* Value may be a percentage of total memory, otherwise bytes */
7393 	coremem = simple_strtoull(p, &endptr, 0);
7394 	if (*endptr == '%') {
7395 		/* Paranoid check for percent values greater than 100 */
7396 		WARN_ON(coremem > 100);
7397 
7398 		*percent = coremem;
7399 	} else {
7400 		coremem = memparse(p, &p);
7401 		/* Paranoid check that UL is enough for the coremem value */
7402 		WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
7403 
7404 		*core = coremem >> PAGE_SHIFT;
7405 		*percent = 0UL;
7406 	}
7407 	return 0;
7408 }
7409 
7410 /*
7411  * kernelcore=size sets the amount of memory for use for allocations that
7412  * cannot be reclaimed or migrated.
7413  */
7414 static int __init cmdline_parse_kernelcore(char *p)
7415 {
7416 	/* parse kernelcore=mirror */
7417 	if (parse_option_str(p, "mirror")) {
7418 		mirrored_kernelcore = true;
7419 		return 0;
7420 	}
7421 
7422 	return cmdline_parse_core(p, &required_kernelcore,
7423 				  &required_kernelcore_percent);
7424 }
7425 
7426 /*
7427  * movablecore=size sets the amount of memory for use for allocations that
7428  * can be reclaimed or migrated.
7429  */
7430 static int __init cmdline_parse_movablecore(char *p)
7431 {
7432 	return cmdline_parse_core(p, &required_movablecore,
7433 				  &required_movablecore_percent);
7434 }
7435 
7436 early_param("kernelcore", cmdline_parse_kernelcore);
7437 early_param("movablecore", cmdline_parse_movablecore);
7438 
7439 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
7440 
7441 void adjust_managed_page_count(struct page *page, long count)
7442 {
7443 	atomic_long_add(count, &page_zone(page)->managed_pages);
7444 	totalram_pages_add(count);
7445 #ifdef CONFIG_HIGHMEM
7446 	if (PageHighMem(page))
7447 		totalhigh_pages_add(count);
7448 #endif
7449 }
7450 EXPORT_SYMBOL(adjust_managed_page_count);
7451 
7452 unsigned long free_reserved_area(void *start, void *end, int poison, const char *s)
7453 {
7454 	void *pos;
7455 	unsigned long pages = 0;
7456 
7457 	start = (void *)PAGE_ALIGN((unsigned long)start);
7458 	end = (void *)((unsigned long)end & PAGE_MASK);
7459 	for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
7460 		struct page *page = virt_to_page(pos);
7461 		void *direct_map_addr;
7462 
7463 		/*
7464 		 * 'direct_map_addr' might be different from 'pos'
7465 		 * because some architectures' virt_to_page()
7466 		 * work with aliases.  Getting the direct map
7467 		 * address ensures that we get a _writeable_
7468 		 * alias for the memset().
7469 		 */
7470 		direct_map_addr = page_address(page);
7471 		if ((unsigned int)poison <= 0xFF)
7472 			memset(direct_map_addr, poison, PAGE_SIZE);
7473 
7474 		free_reserved_page(page);
7475 	}
7476 
7477 	if (pages && s)
7478 		pr_info("Freeing %s memory: %ldK\n",
7479 			s, pages << (PAGE_SHIFT - 10));
7480 
7481 	return pages;
7482 }
7483 
7484 #ifdef	CONFIG_HIGHMEM
7485 void free_highmem_page(struct page *page)
7486 {
7487 	__free_reserved_page(page);
7488 	totalram_pages_inc();
7489 	atomic_long_inc(&page_zone(page)->managed_pages);
7490 	totalhigh_pages_inc();
7491 }
7492 #endif
7493 
7494 
7495 void __init mem_init_print_info(const char *str)
7496 {
7497 	unsigned long physpages, codesize, datasize, rosize, bss_size;
7498 	unsigned long init_code_size, init_data_size;
7499 
7500 	physpages = get_num_physpages();
7501 	codesize = _etext - _stext;
7502 	datasize = _edata - _sdata;
7503 	rosize = __end_rodata - __start_rodata;
7504 	bss_size = __bss_stop - __bss_start;
7505 	init_data_size = __init_end - __init_begin;
7506 	init_code_size = _einittext - _sinittext;
7507 
7508 	/*
7509 	 * Detect special cases and adjust section sizes accordingly:
7510 	 * 1) .init.* may be embedded into .data sections
7511 	 * 2) .init.text.* may be out of [__init_begin, __init_end],
7512 	 *    please refer to arch/tile/kernel/vmlinux.lds.S.
7513 	 * 3) .rodata.* may be embedded into .text or .data sections.
7514 	 */
7515 #define adj_init_size(start, end, size, pos, adj) \
7516 	do { \
7517 		if (start <= pos && pos < end && size > adj) \
7518 			size -= adj; \
7519 	} while (0)
7520 
7521 	adj_init_size(__init_begin, __init_end, init_data_size,
7522 		     _sinittext, init_code_size);
7523 	adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
7524 	adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
7525 	adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
7526 	adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
7527 
7528 #undef	adj_init_size
7529 
7530 	pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
7531 #ifdef	CONFIG_HIGHMEM
7532 		", %luK highmem"
7533 #endif
7534 		"%s%s)\n",
7535 		nr_free_pages() << (PAGE_SHIFT - 10),
7536 		physpages << (PAGE_SHIFT - 10),
7537 		codesize >> 10, datasize >> 10, rosize >> 10,
7538 		(init_data_size + init_code_size) >> 10, bss_size >> 10,
7539 		(physpages - totalram_pages() - totalcma_pages) << (PAGE_SHIFT - 10),
7540 		totalcma_pages << (PAGE_SHIFT - 10),
7541 #ifdef	CONFIG_HIGHMEM
7542 		totalhigh_pages() << (PAGE_SHIFT - 10),
7543 #endif
7544 		str ? ", " : "", str ? str : "");
7545 }
7546 
7547 /**
7548  * set_dma_reserve - set the specified number of pages reserved in the first zone
7549  * @new_dma_reserve: The number of pages to mark reserved
7550  *
7551  * The per-cpu batchsize and zone watermarks are determined by managed_pages.
7552  * In the DMA zone, a significant percentage may be consumed by kernel image
7553  * and other unfreeable allocations which can skew the watermarks badly. This
7554  * function may optionally be used to account for unfreeable pages in the
7555  * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
7556  * smaller per-cpu batchsize.
7557  */
7558 void __init set_dma_reserve(unsigned long new_dma_reserve)
7559 {
7560 	dma_reserve = new_dma_reserve;
7561 }
7562 
7563 void __init free_area_init(unsigned long *zones_size)
7564 {
7565 	zero_resv_unavail();
7566 	free_area_init_node(0, zones_size,
7567 			__pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
7568 }
7569 
7570 static int page_alloc_cpu_dead(unsigned int cpu)
7571 {
7572 
7573 	lru_add_drain_cpu(cpu);
7574 	drain_pages(cpu);
7575 
7576 	/*
7577 	 * Spill the event counters of the dead processor
7578 	 * into the current processors event counters.
7579 	 * This artificially elevates the count of the current
7580 	 * processor.
7581 	 */
7582 	vm_events_fold_cpu(cpu);
7583 
7584 	/*
7585 	 * Zero the differential counters of the dead processor
7586 	 * so that the vm statistics are consistent.
7587 	 *
7588 	 * This is only okay since the processor is dead and cannot
7589 	 * race with what we are doing.
7590 	 */
7591 	cpu_vm_stats_fold(cpu);
7592 	return 0;
7593 }
7594 
7595 #ifdef CONFIG_NUMA
7596 int hashdist = HASHDIST_DEFAULT;
7597 
7598 static int __init set_hashdist(char *str)
7599 {
7600 	if (!str)
7601 		return 0;
7602 	hashdist = simple_strtoul(str, &str, 0);
7603 	return 1;
7604 }
7605 __setup("hashdist=", set_hashdist);
7606 #endif
7607 
7608 void __init page_alloc_init(void)
7609 {
7610 	int ret;
7611 
7612 #ifdef CONFIG_NUMA
7613 	if (num_node_state(N_MEMORY) == 1)
7614 		hashdist = 0;
7615 #endif
7616 
7617 	ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC_DEAD,
7618 					"mm/page_alloc:dead", NULL,
7619 					page_alloc_cpu_dead);
7620 	WARN_ON(ret < 0);
7621 }
7622 
7623 /*
7624  * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio
7625  *	or min_free_kbytes changes.
7626  */
7627 static void calculate_totalreserve_pages(void)
7628 {
7629 	struct pglist_data *pgdat;
7630 	unsigned long reserve_pages = 0;
7631 	enum zone_type i, j;
7632 
7633 	for_each_online_pgdat(pgdat) {
7634 
7635 		pgdat->totalreserve_pages = 0;
7636 
7637 		for (i = 0; i < MAX_NR_ZONES; i++) {
7638 			struct zone *zone = pgdat->node_zones + i;
7639 			long max = 0;
7640 			unsigned long managed_pages = zone_managed_pages(zone);
7641 
7642 			/* Find valid and maximum lowmem_reserve in the zone */
7643 			for (j = i; j < MAX_NR_ZONES; j++) {
7644 				if (zone->lowmem_reserve[j] > max)
7645 					max = zone->lowmem_reserve[j];
7646 			}
7647 
7648 			/* we treat the high watermark as reserved pages. */
7649 			max += high_wmark_pages(zone);
7650 
7651 			if (max > managed_pages)
7652 				max = managed_pages;
7653 
7654 			pgdat->totalreserve_pages += max;
7655 
7656 			reserve_pages += max;
7657 		}
7658 	}
7659 	totalreserve_pages = reserve_pages;
7660 }
7661 
7662 /*
7663  * setup_per_zone_lowmem_reserve - called whenever
7664  *	sysctl_lowmem_reserve_ratio changes.  Ensures that each zone
7665  *	has a correct pages reserved value, so an adequate number of
7666  *	pages are left in the zone after a successful __alloc_pages().
7667  */
7668 static void setup_per_zone_lowmem_reserve(void)
7669 {
7670 	struct pglist_data *pgdat;
7671 	enum zone_type j, idx;
7672 
7673 	for_each_online_pgdat(pgdat) {
7674 		for (j = 0; j < MAX_NR_ZONES; j++) {
7675 			struct zone *zone = pgdat->node_zones + j;
7676 			unsigned long managed_pages = zone_managed_pages(zone);
7677 
7678 			zone->lowmem_reserve[j] = 0;
7679 
7680 			idx = j;
7681 			while (idx) {
7682 				struct zone *lower_zone;
7683 
7684 				idx--;
7685 				lower_zone = pgdat->node_zones + idx;
7686 
7687 				if (sysctl_lowmem_reserve_ratio[idx] < 1) {
7688 					sysctl_lowmem_reserve_ratio[idx] = 0;
7689 					lower_zone->lowmem_reserve[j] = 0;
7690 				} else {
7691 					lower_zone->lowmem_reserve[j] =
7692 						managed_pages / sysctl_lowmem_reserve_ratio[idx];
7693 				}
7694 				managed_pages += zone_managed_pages(lower_zone);
7695 			}
7696 		}
7697 	}
7698 
7699 	/* update totalreserve_pages */
7700 	calculate_totalreserve_pages();
7701 }
7702 
7703 static void __setup_per_zone_wmarks(void)
7704 {
7705 	unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
7706 	unsigned long lowmem_pages = 0;
7707 	struct zone *zone;
7708 	unsigned long flags;
7709 
7710 	/* Calculate total number of !ZONE_HIGHMEM pages */
7711 	for_each_zone(zone) {
7712 		if (!is_highmem(zone))
7713 			lowmem_pages += zone_managed_pages(zone);
7714 	}
7715 
7716 	for_each_zone(zone) {
7717 		u64 tmp;
7718 
7719 		spin_lock_irqsave(&zone->lock, flags);
7720 		tmp = (u64)pages_min * zone_managed_pages(zone);
7721 		do_div(tmp, lowmem_pages);
7722 		if (is_highmem(zone)) {
7723 			/*
7724 			 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
7725 			 * need highmem pages, so cap pages_min to a small
7726 			 * value here.
7727 			 *
7728 			 * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
7729 			 * deltas control async page reclaim, and so should
7730 			 * not be capped for highmem.
7731 			 */
7732 			unsigned long min_pages;
7733 
7734 			min_pages = zone_managed_pages(zone) / 1024;
7735 			min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
7736 			zone->_watermark[WMARK_MIN] = min_pages;
7737 		} else {
7738 			/*
7739 			 * If it's a lowmem zone, reserve a number of pages
7740 			 * proportionate to the zone's size.
7741 			 */
7742 			zone->_watermark[WMARK_MIN] = tmp;
7743 		}
7744 
7745 		/*
7746 		 * Set the kswapd watermarks distance according to the
7747 		 * scale factor in proportion to available memory, but
7748 		 * ensure a minimum size on small systems.
7749 		 */
7750 		tmp = max_t(u64, tmp >> 2,
7751 			    mult_frac(zone_managed_pages(zone),
7752 				      watermark_scale_factor, 10000));
7753 
7754 		zone->_watermark[WMARK_LOW]  = min_wmark_pages(zone) + tmp;
7755 		zone->_watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;
7756 		zone->watermark_boost = 0;
7757 
7758 		spin_unlock_irqrestore(&zone->lock, flags);
7759 	}
7760 
7761 	/* update totalreserve_pages */
7762 	calculate_totalreserve_pages();
7763 }
7764 
7765 /**
7766  * setup_per_zone_wmarks - called when min_free_kbytes changes
7767  * or when memory is hot-{added|removed}
7768  *
7769  * Ensures that the watermark[min,low,high] values for each zone are set
7770  * correctly with respect to min_free_kbytes.
7771  */
7772 void setup_per_zone_wmarks(void)
7773 {
7774 	static DEFINE_SPINLOCK(lock);
7775 
7776 	spin_lock(&lock);
7777 	__setup_per_zone_wmarks();
7778 	spin_unlock(&lock);
7779 }
7780 
7781 /*
7782  * Initialise min_free_kbytes.
7783  *
7784  * For small machines we want it small (128k min).  For large machines
7785  * we want it large (64MB max).  But it is not linear, because network
7786  * bandwidth does not increase linearly with machine size.  We use
7787  *
7788  *	min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
7789  *	min_free_kbytes = sqrt(lowmem_kbytes * 16)
7790  *
7791  * which yields
7792  *
7793  * 16MB:	512k
7794  * 32MB:	724k
7795  * 64MB:	1024k
7796  * 128MB:	1448k
7797  * 256MB:	2048k
7798  * 512MB:	2896k
7799  * 1024MB:	4096k
7800  * 2048MB:	5792k
7801  * 4096MB:	8192k
7802  * 8192MB:	11584k
7803  * 16384MB:	16384k
7804  */
7805 int __meminit init_per_zone_wmark_min(void)
7806 {
7807 	unsigned long lowmem_kbytes;
7808 	int new_min_free_kbytes;
7809 
7810 	lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
7811 	new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
7812 
7813 	if (new_min_free_kbytes > user_min_free_kbytes) {
7814 		min_free_kbytes = new_min_free_kbytes;
7815 		if (min_free_kbytes < 128)
7816 			min_free_kbytes = 128;
7817 		if (min_free_kbytes > 65536)
7818 			min_free_kbytes = 65536;
7819 	} else {
7820 		pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
7821 				new_min_free_kbytes, user_min_free_kbytes);
7822 	}
7823 	setup_per_zone_wmarks();
7824 	refresh_zone_stat_thresholds();
7825 	setup_per_zone_lowmem_reserve();
7826 
7827 #ifdef CONFIG_NUMA
7828 	setup_min_unmapped_ratio();
7829 	setup_min_slab_ratio();
7830 #endif
7831 
7832 	return 0;
7833 }
7834 core_initcall(init_per_zone_wmark_min)
7835 
7836 /*
7837  * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
7838  *	that we can call two helper functions whenever min_free_kbytes
7839  *	changes.
7840  */
7841 int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
7842 	void __user *buffer, size_t *length, loff_t *ppos)
7843 {
7844 	int rc;
7845 
7846 	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7847 	if (rc)
7848 		return rc;
7849 
7850 	if (write) {
7851 		user_min_free_kbytes = min_free_kbytes;
7852 		setup_per_zone_wmarks();
7853 	}
7854 	return 0;
7855 }
7856 
7857 int watermark_boost_factor_sysctl_handler(struct ctl_table *table, int write,
7858 	void __user *buffer, size_t *length, loff_t *ppos)
7859 {
7860 	int rc;
7861 
7862 	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7863 	if (rc)
7864 		return rc;
7865 
7866 	return 0;
7867 }
7868 
7869 int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
7870 	void __user *buffer, size_t *length, loff_t *ppos)
7871 {
7872 	int rc;
7873 
7874 	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7875 	if (rc)
7876 		return rc;
7877 
7878 	if (write)
7879 		setup_per_zone_wmarks();
7880 
7881 	return 0;
7882 }
7883 
7884 #ifdef CONFIG_NUMA
7885 static void setup_min_unmapped_ratio(void)
7886 {
7887 	pg_data_t *pgdat;
7888 	struct zone *zone;
7889 
7890 	for_each_online_pgdat(pgdat)
7891 		pgdat->min_unmapped_pages = 0;
7892 
7893 	for_each_zone(zone)
7894 		zone->zone_pgdat->min_unmapped_pages += (zone_managed_pages(zone) *
7895 						         sysctl_min_unmapped_ratio) / 100;
7896 }
7897 
7898 
7899 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
7900 	void __user *buffer, size_t *length, loff_t *ppos)
7901 {
7902 	int rc;
7903 
7904 	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7905 	if (rc)
7906 		return rc;
7907 
7908 	setup_min_unmapped_ratio();
7909 
7910 	return 0;
7911 }
7912 
7913 static void setup_min_slab_ratio(void)
7914 {
7915 	pg_data_t *pgdat;
7916 	struct zone *zone;
7917 
7918 	for_each_online_pgdat(pgdat)
7919 		pgdat->min_slab_pages = 0;
7920 
7921 	for_each_zone(zone)
7922 		zone->zone_pgdat->min_slab_pages += (zone_managed_pages(zone) *
7923 						     sysctl_min_slab_ratio) / 100;
7924 }
7925 
7926 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
7927 	void __user *buffer, size_t *length, loff_t *ppos)
7928 {
7929 	int rc;
7930 
7931 	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
7932 	if (rc)
7933 		return rc;
7934 
7935 	setup_min_slab_ratio();
7936 
7937 	return 0;
7938 }
7939 #endif
7940 
7941 /*
7942  * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
7943  *	proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
7944  *	whenever sysctl_lowmem_reserve_ratio changes.
7945  *
7946  * The reserve ratio obviously has absolutely no relation with the
7947  * minimum watermarks. The lowmem reserve ratio can only make sense
7948  * if in function of the boot time zone sizes.
7949  */
7950 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
7951 	void __user *buffer, size_t *length, loff_t *ppos)
7952 {
7953 	proc_dointvec_minmax(table, write, buffer, length, ppos);
7954 	setup_per_zone_lowmem_reserve();
7955 	return 0;
7956 }
7957 
7958 /*
7959  * percpu_pagelist_fraction - changes the pcp->high for each zone on each
7960  * cpu.  It is the fraction of total pages in each zone that a hot per cpu
7961  * pagelist can have before it gets flushed back to buddy allocator.
7962  */
7963 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write,
7964 	void __user *buffer, size_t *length, loff_t *ppos)
7965 {
7966 	struct zone *zone;
7967 	int old_percpu_pagelist_fraction;
7968 	int ret;
7969 
7970 	mutex_lock(&pcp_batch_high_lock);
7971 	old_percpu_pagelist_fraction = percpu_pagelist_fraction;
7972 
7973 	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
7974 	if (!write || ret < 0)
7975 		goto out;
7976 
7977 	/* Sanity checking to avoid pcp imbalance */
7978 	if (percpu_pagelist_fraction &&
7979 	    percpu_pagelist_fraction < MIN_PERCPU_PAGELIST_FRACTION) {
7980 		percpu_pagelist_fraction = old_percpu_pagelist_fraction;
7981 		ret = -EINVAL;
7982 		goto out;
7983 	}
7984 
7985 	/* No change? */
7986 	if (percpu_pagelist_fraction == old_percpu_pagelist_fraction)
7987 		goto out;
7988 
7989 	for_each_populated_zone(zone) {
7990 		unsigned int cpu;
7991 
7992 		for_each_possible_cpu(cpu)
7993 			pageset_set_high_and_batch(zone,
7994 					per_cpu_ptr(zone->pageset, cpu));
7995 	}
7996 out:
7997 	mutex_unlock(&pcp_batch_high_lock);
7998 	return ret;
7999 }
8000 
8001 #ifndef __HAVE_ARCH_RESERVED_KERNEL_PAGES
8002 /*
8003  * Returns the number of pages that arch has reserved but
8004  * is not known to alloc_large_system_hash().
8005  */
8006 static unsigned long __init arch_reserved_kernel_pages(void)
8007 {
8008 	return 0;
8009 }
8010 #endif
8011 
8012 /*
8013  * Adaptive scale is meant to reduce sizes of hash tables on large memory
8014  * machines. As memory size is increased the scale is also increased but at
8015  * slower pace.  Starting from ADAPT_SCALE_BASE (64G), every time memory
8016  * quadruples the scale is increased by one, which means the size of hash table
8017  * only doubles, instead of quadrupling as well.
8018  * Because 32-bit systems cannot have large physical memory, where this scaling
8019  * makes sense, it is disabled on such platforms.
8020  */
8021 #if __BITS_PER_LONG > 32
8022 #define ADAPT_SCALE_BASE	(64ul << 30)
8023 #define ADAPT_SCALE_SHIFT	2
8024 #define ADAPT_SCALE_NPAGES	(ADAPT_SCALE_BASE >> PAGE_SHIFT)
8025 #endif
8026 
8027 /*
8028  * allocate a large system hash table from bootmem
8029  * - it is assumed that the hash table must contain an exact power-of-2
8030  *   quantity of entries
8031  * - limit is the number of hash buckets, not the total allocation size
8032  */
8033 void *__init alloc_large_system_hash(const char *tablename,
8034 				     unsigned long bucketsize,
8035 				     unsigned long numentries,
8036 				     int scale,
8037 				     int flags,
8038 				     unsigned int *_hash_shift,
8039 				     unsigned int *_hash_mask,
8040 				     unsigned long low_limit,
8041 				     unsigned long high_limit)
8042 {
8043 	unsigned long long max = high_limit;
8044 	unsigned long log2qty, size;
8045 	void *table = NULL;
8046 	gfp_t gfp_flags;
8047 	bool virt;
8048 
8049 	/* allow the kernel cmdline to have a say */
8050 	if (!numentries) {
8051 		/* round applicable memory size up to nearest megabyte */
8052 		numentries = nr_kernel_pages;
8053 		numentries -= arch_reserved_kernel_pages();
8054 
8055 		/* It isn't necessary when PAGE_SIZE >= 1MB */
8056 		if (PAGE_SHIFT < 20)
8057 			numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
8058 
8059 #if __BITS_PER_LONG > 32
8060 		if (!high_limit) {
8061 			unsigned long adapt;
8062 
8063 			for (adapt = ADAPT_SCALE_NPAGES; adapt < numentries;
8064 			     adapt <<= ADAPT_SCALE_SHIFT)
8065 				scale++;
8066 		}
8067 #endif
8068 
8069 		/* limit to 1 bucket per 2^scale bytes of low memory */
8070 		if (scale > PAGE_SHIFT)
8071 			numentries >>= (scale - PAGE_SHIFT);
8072 		else
8073 			numentries <<= (PAGE_SHIFT - scale);
8074 
8075 		/* Make sure we've got at least a 0-order allocation.. */
8076 		if (unlikely(flags & HASH_SMALL)) {
8077 			/* Makes no sense without HASH_EARLY */
8078 			WARN_ON(!(flags & HASH_EARLY));
8079 			if (!(numentries >> *_hash_shift)) {
8080 				numentries = 1UL << *_hash_shift;
8081 				BUG_ON(!numentries);
8082 			}
8083 		} else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
8084 			numentries = PAGE_SIZE / bucketsize;
8085 	}
8086 	numentries = roundup_pow_of_two(numentries);
8087 
8088 	/* limit allocation size to 1/16 total memory by default */
8089 	if (max == 0) {
8090 		max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
8091 		do_div(max, bucketsize);
8092 	}
8093 	max = min(max, 0x80000000ULL);
8094 
8095 	if (numentries < low_limit)
8096 		numentries = low_limit;
8097 	if (numentries > max)
8098 		numentries = max;
8099 
8100 	log2qty = ilog2(numentries);
8101 
8102 	gfp_flags = (flags & HASH_ZERO) ? GFP_ATOMIC | __GFP_ZERO : GFP_ATOMIC;
8103 	do {
8104 		virt = false;
8105 		size = bucketsize << log2qty;
8106 		if (flags & HASH_EARLY) {
8107 			if (flags & HASH_ZERO)
8108 				table = memblock_alloc(size, SMP_CACHE_BYTES);
8109 			else
8110 				table = memblock_alloc_raw(size,
8111 							   SMP_CACHE_BYTES);
8112 		} else if (get_order(size) >= MAX_ORDER || hashdist) {
8113 			table = __vmalloc(size, gfp_flags, PAGE_KERNEL);
8114 			virt = true;
8115 		} else {
8116 			/*
8117 			 * If bucketsize is not a power-of-two, we may free
8118 			 * some pages at the end of hash table which
8119 			 * alloc_pages_exact() automatically does
8120 			 */
8121 			table = alloc_pages_exact(size, gfp_flags);
8122 			kmemleak_alloc(table, size, 1, gfp_flags);
8123 		}
8124 	} while (!table && size > PAGE_SIZE && --log2qty);
8125 
8126 	if (!table)
8127 		panic("Failed to allocate %s hash table\n", tablename);
8128 
8129 	pr_info("%s hash table entries: %ld (order: %d, %lu bytes, %s)\n",
8130 		tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size,
8131 		virt ? "vmalloc" : "linear");
8132 
8133 	if (_hash_shift)
8134 		*_hash_shift = log2qty;
8135 	if (_hash_mask)
8136 		*_hash_mask = (1 << log2qty) - 1;
8137 
8138 	return table;
8139 }
8140 
8141 /*
8142  * This function checks whether pageblock includes unmovable pages or not.
8143  * If @count is not zero, it is okay to include less @count unmovable pages
8144  *
8145  * PageLRU check without isolation or lru_lock could race so that
8146  * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
8147  * check without lock_page also may miss some movable non-lru pages at
8148  * race condition. So you can't expect this function should be exact.
8149  */
8150 bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
8151 			 int migratetype, int flags)
8152 {
8153 	unsigned long found;
8154 	unsigned long iter = 0;
8155 	unsigned long pfn = page_to_pfn(page);
8156 	const char *reason = "unmovable page";
8157 
8158 	/*
8159 	 * TODO we could make this much more efficient by not checking every
8160 	 * page in the range if we know all of them are in MOVABLE_ZONE and
8161 	 * that the movable zone guarantees that pages are migratable but
8162 	 * the later is not the case right now unfortunatelly. E.g. movablecore
8163 	 * can still lead to having bootmem allocations in zone_movable.
8164 	 */
8165 
8166 	if (is_migrate_cma_page(page)) {
8167 		/*
8168 		 * CMA allocations (alloc_contig_range) really need to mark
8169 		 * isolate CMA pageblocks even when they are not movable in fact
8170 		 * so consider them movable here.
8171 		 */
8172 		if (is_migrate_cma(migratetype))
8173 			return false;
8174 
8175 		reason = "CMA page";
8176 		goto unmovable;
8177 	}
8178 
8179 	for (found = 0; iter < pageblock_nr_pages; iter++) {
8180 		unsigned long check = pfn + iter;
8181 
8182 		if (!pfn_valid_within(check))
8183 			continue;
8184 
8185 		page = pfn_to_page(check);
8186 
8187 		if (PageReserved(page))
8188 			goto unmovable;
8189 
8190 		/*
8191 		 * If the zone is movable and we have ruled out all reserved
8192 		 * pages then it should be reasonably safe to assume the rest
8193 		 * is movable.
8194 		 */
8195 		if (zone_idx(zone) == ZONE_MOVABLE)
8196 			continue;
8197 
8198 		/*
8199 		 * Hugepages are not in LRU lists, but they're movable.
8200 		 * We need not scan over tail pages because we don't
8201 		 * handle each tail page individually in migration.
8202 		 */
8203 		if (PageHuge(page)) {
8204 			struct page *head = compound_head(page);
8205 			unsigned int skip_pages;
8206 
8207 			if (!hugepage_migration_supported(page_hstate(head)))
8208 				goto unmovable;
8209 
8210 			skip_pages = compound_nr(head) - (page - head);
8211 			iter += skip_pages - 1;
8212 			continue;
8213 		}
8214 
8215 		/*
8216 		 * We can't use page_count without pin a page
8217 		 * because another CPU can free compound page.
8218 		 * This check already skips compound tails of THP
8219 		 * because their page->_refcount is zero at all time.
8220 		 */
8221 		if (!page_ref_count(page)) {
8222 			if (PageBuddy(page))
8223 				iter += (1 << page_order(page)) - 1;
8224 			continue;
8225 		}
8226 
8227 		/*
8228 		 * The HWPoisoned page may be not in buddy system, and
8229 		 * page_count() is not 0.
8230 		 */
8231 		if ((flags & SKIP_HWPOISON) && PageHWPoison(page))
8232 			continue;
8233 
8234 		if (__PageMovable(page))
8235 			continue;
8236 
8237 		if (!PageLRU(page))
8238 			found++;
8239 		/*
8240 		 * If there are RECLAIMABLE pages, we need to check
8241 		 * it.  But now, memory offline itself doesn't call
8242 		 * shrink_node_slabs() and it still to be fixed.
8243 		 */
8244 		/*
8245 		 * If the page is not RAM, page_count()should be 0.
8246 		 * we don't need more check. This is an _used_ not-movable page.
8247 		 *
8248 		 * The problematic thing here is PG_reserved pages. PG_reserved
8249 		 * is set to both of a memory hole page and a _used_ kernel
8250 		 * page at boot.
8251 		 */
8252 		if (found > count)
8253 			goto unmovable;
8254 	}
8255 	return false;
8256 unmovable:
8257 	WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE);
8258 	if (flags & REPORT_FAILURE)
8259 		dump_page(pfn_to_page(pfn + iter), reason);
8260 	return true;
8261 }
8262 
8263 #ifdef CONFIG_CONTIG_ALLOC
8264 static unsigned long pfn_max_align_down(unsigned long pfn)
8265 {
8266 	return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
8267 			     pageblock_nr_pages) - 1);
8268 }
8269 
8270 static unsigned long pfn_max_align_up(unsigned long pfn)
8271 {
8272 	return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
8273 				pageblock_nr_pages));
8274 }
8275 
8276 /* [start, end) must belong to a single zone. */
8277 static int __alloc_contig_migrate_range(struct compact_control *cc,
8278 					unsigned long start, unsigned long end)
8279 {
8280 	/* This function is based on compact_zone() from compaction.c. */
8281 	unsigned long nr_reclaimed;
8282 	unsigned long pfn = start;
8283 	unsigned int tries = 0;
8284 	int ret = 0;
8285 
8286 	migrate_prep();
8287 
8288 	while (pfn < end || !list_empty(&cc->migratepages)) {
8289 		if (fatal_signal_pending(current)) {
8290 			ret = -EINTR;
8291 			break;
8292 		}
8293 
8294 		if (list_empty(&cc->migratepages)) {
8295 			cc->nr_migratepages = 0;
8296 			pfn = isolate_migratepages_range(cc, pfn, end);
8297 			if (!pfn) {
8298 				ret = -EINTR;
8299 				break;
8300 			}
8301 			tries = 0;
8302 		} else if (++tries == 5) {
8303 			ret = ret < 0 ? ret : -EBUSY;
8304 			break;
8305 		}
8306 
8307 		nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
8308 							&cc->migratepages);
8309 		cc->nr_migratepages -= nr_reclaimed;
8310 
8311 		ret = migrate_pages(&cc->migratepages, alloc_migrate_target,
8312 				    NULL, 0, cc->mode, MR_CONTIG_RANGE);
8313 	}
8314 	if (ret < 0) {
8315 		putback_movable_pages(&cc->migratepages);
8316 		return ret;
8317 	}
8318 	return 0;
8319 }
8320 
8321 /**
8322  * alloc_contig_range() -- tries to allocate given range of pages
8323  * @start:	start PFN to allocate
8324  * @end:	one-past-the-last PFN to allocate
8325  * @migratetype:	migratetype of the underlaying pageblocks (either
8326  *			#MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
8327  *			in range must have the same migratetype and it must
8328  *			be either of the two.
8329  * @gfp_mask:	GFP mask to use during compaction
8330  *
8331  * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
8332  * aligned.  The PFN range must belong to a single zone.
8333  *
8334  * The first thing this routine does is attempt to MIGRATE_ISOLATE all
8335  * pageblocks in the range.  Once isolated, the pageblocks should not
8336  * be modified by others.
8337  *
8338  * Return: zero on success or negative error code.  On success all
8339  * pages which PFN is in [start, end) are allocated for the caller and
8340  * need to be freed with free_contig_range().
8341  */
8342 int alloc_contig_range(unsigned long start, unsigned long end,
8343 		       unsigned migratetype, gfp_t gfp_mask)
8344 {
8345 	unsigned long outer_start, outer_end;
8346 	unsigned int order;
8347 	int ret = 0;
8348 
8349 	struct compact_control cc = {
8350 		.nr_migratepages = 0,
8351 		.order = -1,
8352 		.zone = page_zone(pfn_to_page(start)),
8353 		.mode = MIGRATE_SYNC,
8354 		.ignore_skip_hint = true,
8355 		.no_set_skip_hint = true,
8356 		.gfp_mask = current_gfp_context(gfp_mask),
8357 	};
8358 	INIT_LIST_HEAD(&cc.migratepages);
8359 
8360 	/*
8361 	 * What we do here is we mark all pageblocks in range as
8362 	 * MIGRATE_ISOLATE.  Because pageblock and max order pages may
8363 	 * have different sizes, and due to the way page allocator
8364 	 * work, we align the range to biggest of the two pages so
8365 	 * that page allocator won't try to merge buddies from
8366 	 * different pageblocks and change MIGRATE_ISOLATE to some
8367 	 * other migration type.
8368 	 *
8369 	 * Once the pageblocks are marked as MIGRATE_ISOLATE, we
8370 	 * migrate the pages from an unaligned range (ie. pages that
8371 	 * we are interested in).  This will put all the pages in
8372 	 * range back to page allocator as MIGRATE_ISOLATE.
8373 	 *
8374 	 * When this is done, we take the pages in range from page
8375 	 * allocator removing them from the buddy system.  This way
8376 	 * page allocator will never consider using them.
8377 	 *
8378 	 * This lets us mark the pageblocks back as
8379 	 * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
8380 	 * aligned range but not in the unaligned, original range are
8381 	 * put back to page allocator so that buddy can use them.
8382 	 */
8383 
8384 	ret = start_isolate_page_range(pfn_max_align_down(start),
8385 				       pfn_max_align_up(end), migratetype, 0);
8386 	if (ret < 0)
8387 		return ret;
8388 
8389 	/*
8390 	 * In case of -EBUSY, we'd like to know which page causes problem.
8391 	 * So, just fall through. test_pages_isolated() has a tracepoint
8392 	 * which will report the busy page.
8393 	 *
8394 	 * It is possible that busy pages could become available before
8395 	 * the call to test_pages_isolated, and the range will actually be
8396 	 * allocated.  So, if we fall through be sure to clear ret so that
8397 	 * -EBUSY is not accidentally used or returned to caller.
8398 	 */
8399 	ret = __alloc_contig_migrate_range(&cc, start, end);
8400 	if (ret && ret != -EBUSY)
8401 		goto done;
8402 	ret =0;
8403 
8404 	/*
8405 	 * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
8406 	 * aligned blocks that are marked as MIGRATE_ISOLATE.  What's
8407 	 * more, all pages in [start, end) are free in page allocator.
8408 	 * What we are going to do is to allocate all pages from
8409 	 * [start, end) (that is remove them from page allocator).
8410 	 *
8411 	 * The only problem is that pages at the beginning and at the
8412 	 * end of interesting range may be not aligned with pages that
8413 	 * page allocator holds, ie. they can be part of higher order
8414 	 * pages.  Because of this, we reserve the bigger range and
8415 	 * once this is done free the pages we are not interested in.
8416 	 *
8417 	 * We don't have to hold zone->lock here because the pages are
8418 	 * isolated thus they won't get removed from buddy.
8419 	 */
8420 
8421 	lru_add_drain_all();
8422 
8423 	order = 0;
8424 	outer_start = start;
8425 	while (!PageBuddy(pfn_to_page(outer_start))) {
8426 		if (++order >= MAX_ORDER) {
8427 			outer_start = start;
8428 			break;
8429 		}
8430 		outer_start &= ~0UL << order;
8431 	}
8432 
8433 	if (outer_start != start) {
8434 		order = page_order(pfn_to_page(outer_start));
8435 
8436 		/*
8437 		 * outer_start page could be small order buddy page and
8438 		 * it doesn't include start page. Adjust outer_start
8439 		 * in this case to report failed page properly
8440 		 * on tracepoint in test_pages_isolated()
8441 		 */
8442 		if (outer_start + (1UL << order) <= start)
8443 			outer_start = start;
8444 	}
8445 
8446 	/* Make sure the range is really isolated. */
8447 	if (test_pages_isolated(outer_start, end, false)) {
8448 		pr_info_ratelimited("%s: [%lx, %lx) PFNs busy\n",
8449 			__func__, outer_start, end);
8450 		ret = -EBUSY;
8451 		goto done;
8452 	}
8453 
8454 	/* Grab isolated pages from freelists. */
8455 	outer_end = isolate_freepages_range(&cc, outer_start, end);
8456 	if (!outer_end) {
8457 		ret = -EBUSY;
8458 		goto done;
8459 	}
8460 
8461 	/* Free head and tail (if any) */
8462 	if (start != outer_start)
8463 		free_contig_range(outer_start, start - outer_start);
8464 	if (end != outer_end)
8465 		free_contig_range(end, outer_end - end);
8466 
8467 done:
8468 	undo_isolate_page_range(pfn_max_align_down(start),
8469 				pfn_max_align_up(end), migratetype);
8470 	return ret;
8471 }
8472 #endif /* CONFIG_CONTIG_ALLOC */
8473 
8474 void free_contig_range(unsigned long pfn, unsigned int nr_pages)
8475 {
8476 	unsigned int count = 0;
8477 
8478 	for (; nr_pages--; pfn++) {
8479 		struct page *page = pfn_to_page(pfn);
8480 
8481 		count += page_count(page) != 1;
8482 		__free_page(page);
8483 	}
8484 	WARN(count != 0, "%d pages are still in use!\n", count);
8485 }
8486 
8487 #ifdef CONFIG_MEMORY_HOTPLUG
8488 /*
8489  * The zone indicated has a new number of managed_pages; batch sizes and percpu
8490  * page high values need to be recalulated.
8491  */
8492 void __meminit zone_pcp_update(struct zone *zone)
8493 {
8494 	unsigned cpu;
8495 	mutex_lock(&pcp_batch_high_lock);
8496 	for_each_possible_cpu(cpu)
8497 		pageset_set_high_and_batch(zone,
8498 				per_cpu_ptr(zone->pageset, cpu));
8499 	mutex_unlock(&pcp_batch_high_lock);
8500 }
8501 #endif
8502 
8503 void zone_pcp_reset(struct zone *zone)
8504 {
8505 	unsigned long flags;
8506 	int cpu;
8507 	struct per_cpu_pageset *pset;
8508 
8509 	/* avoid races with drain_pages()  */
8510 	local_irq_save(flags);
8511 	if (zone->pageset != &boot_pageset) {
8512 		for_each_online_cpu(cpu) {
8513 			pset = per_cpu_ptr(zone->pageset, cpu);
8514 			drain_zonestat(zone, pset);
8515 		}
8516 		free_percpu(zone->pageset);
8517 		zone->pageset = &boot_pageset;
8518 	}
8519 	local_irq_restore(flags);
8520 }
8521 
8522 #ifdef CONFIG_MEMORY_HOTREMOVE
8523 /*
8524  * All pages in the range must be in a single zone and isolated
8525  * before calling this.
8526  */
8527 unsigned long
8528 __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
8529 {
8530 	struct page *page;
8531 	struct zone *zone;
8532 	unsigned int order, i;
8533 	unsigned long pfn;
8534 	unsigned long flags;
8535 	unsigned long offlined_pages = 0;
8536 
8537 	/* find the first valid pfn */
8538 	for (pfn = start_pfn; pfn < end_pfn; pfn++)
8539 		if (pfn_valid(pfn))
8540 			break;
8541 	if (pfn == end_pfn)
8542 		return offlined_pages;
8543 
8544 	offline_mem_sections(pfn, end_pfn);
8545 	zone = page_zone(pfn_to_page(pfn));
8546 	spin_lock_irqsave(&zone->lock, flags);
8547 	pfn = start_pfn;
8548 	while (pfn < end_pfn) {
8549 		if (!pfn_valid(pfn)) {
8550 			pfn++;
8551 			continue;
8552 		}
8553 		page = pfn_to_page(pfn);
8554 		/*
8555 		 * The HWPoisoned page may be not in buddy system, and
8556 		 * page_count() is not 0.
8557 		 */
8558 		if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
8559 			pfn++;
8560 			SetPageReserved(page);
8561 			offlined_pages++;
8562 			continue;
8563 		}
8564 
8565 		BUG_ON(page_count(page));
8566 		BUG_ON(!PageBuddy(page));
8567 		order = page_order(page);
8568 		offlined_pages += 1 << order;
8569 #ifdef CONFIG_DEBUG_VM
8570 		pr_info("remove from free list %lx %d %lx\n",
8571 			pfn, 1 << order, end_pfn);
8572 #endif
8573 		del_page_from_free_area(page, &zone->free_area[order]);
8574 		for (i = 0; i < (1 << order); i++)
8575 			SetPageReserved((page+i));
8576 		pfn += (1 << order);
8577 	}
8578 	spin_unlock_irqrestore(&zone->lock, flags);
8579 
8580 	return offlined_pages;
8581 }
8582 #endif
8583 
8584 bool is_free_buddy_page(struct page *page)
8585 {
8586 	struct zone *zone = page_zone(page);
8587 	unsigned long pfn = page_to_pfn(page);
8588 	unsigned long flags;
8589 	unsigned int order;
8590 
8591 	spin_lock_irqsave(&zone->lock, flags);
8592 	for (order = 0; order < MAX_ORDER; order++) {
8593 		struct page *page_head = page - (pfn & ((1 << order) - 1));
8594 
8595 		if (PageBuddy(page_head) && page_order(page_head) >= order)
8596 			break;
8597 	}
8598 	spin_unlock_irqrestore(&zone->lock, flags);
8599 
8600 	return order < MAX_ORDER;
8601 }
8602 
8603 #ifdef CONFIG_MEMORY_FAILURE
8604 /*
8605  * Set PG_hwpoison flag if a given page is confirmed to be a free page.  This
8606  * test is performed under the zone lock to prevent a race against page
8607  * allocation.
8608  */
8609 bool set_hwpoison_free_buddy_page(struct page *page)
8610 {
8611 	struct zone *zone = page_zone(page);
8612 	unsigned long pfn = page_to_pfn(page);
8613 	unsigned long flags;
8614 	unsigned int order;
8615 	bool hwpoisoned = false;
8616 
8617 	spin_lock_irqsave(&zone->lock, flags);
8618 	for (order = 0; order < MAX_ORDER; order++) {
8619 		struct page *page_head = page - (pfn & ((1 << order) - 1));
8620 
8621 		if (PageBuddy(page_head) && page_order(page_head) >= order) {
8622 			if (!TestSetPageHWPoison(page))
8623 				hwpoisoned = true;
8624 			break;
8625 		}
8626 	}
8627 	spin_unlock_irqrestore(&zone->lock, flags);
8628 
8629 	return hwpoisoned;
8630 }
8631 #endif
8632