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Linux/mm/page_alloc.c

  1 /*
  2  *  linux/mm/page_alloc.c
  3  *
  4  *  Manages the free list, the system allocates free pages here.
  5  *  Note that kmalloc() lives in slab.c
  6  *
  7  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  8  *  Swap reorganised 29.12.95, Stephen Tweedie
  9  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 10  *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
 11  *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
 12  *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
 13  *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
 14  *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
 15  */
 16 
 17 #include <linux/stddef.h>
 18 #include <linux/mm.h>
 19 #include <linux/swap.h>
 20 #include <linux/interrupt.h>
 21 #include <linux/pagemap.h>
 22 #include <linux/jiffies.h>
 23 #include <linux/bootmem.h>
 24 #include <linux/memblock.h>
 25 #include <linux/compiler.h>
 26 #include <linux/kernel.h>
 27 #include <linux/kmemcheck.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/notifier.h>
 37 #include <linux/topology.h>
 38 #include <linux/sysctl.h>
 39 #include <linux/cpu.h>
 40 #include <linux/cpuset.h>
 41 #include <linux/memory_hotplug.h>
 42 #include <linux/nodemask.h>
 43 #include <linux/vmalloc.h>
 44 #include <linux/vmstat.h>
 45 #include <linux/mempolicy.h>
 46 #include <linux/memremap.h>
 47 #include <linux/stop_machine.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/page_ext.h>
 54 #include <linux/debugobjects.h>
 55 #include <linux/kmemleak.h>
 56 #include <linux/compaction.h>
 57 #include <trace/events/kmem.h>
 58 #include <linux/prefetch.h>
 59 #include <linux/mm_inline.h>
 60 #include <linux/migrate.h>
 61 #include <linux/page_ext.h>
 62 #include <linux/hugetlb.h>
 63 #include <linux/sched/rt.h>
 64 #include <linux/page_owner.h>
 65 #include <linux/kthread.h>
 66 #include <linux/memcontrol.h>
 67 
 68 #include <asm/sections.h>
 69 #include <asm/tlbflush.h>
 70 #include <asm/div64.h>
 71 #include "internal.h"
 72 
 73 /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
 74 static DEFINE_MUTEX(pcp_batch_high_lock);
 75 #define MIN_PERCPU_PAGELIST_FRACTION    (8)
 76 
 77 #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
 78 DEFINE_PER_CPU(int, numa_node);
 79 EXPORT_PER_CPU_SYMBOL(numa_node);
 80 #endif
 81 
 82 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
 83 /*
 84  * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
 85  * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
 86  * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
 87  * defined in <linux/topology.h>.
 88  */
 89 DEFINE_PER_CPU(int, _numa_mem_);                /* Kernel "local memory" node */
 90 EXPORT_PER_CPU_SYMBOL(_numa_mem_);
 91 int _node_numa_mem_[MAX_NUMNODES];
 92 #endif
 93 
 94 #ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
 95 volatile unsigned long latent_entropy __latent_entropy;
 96 EXPORT_SYMBOL(latent_entropy);
 97 #endif
 98 
 99 /*
100  * Array of node states.
101  */
102 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
103         [N_POSSIBLE] = NODE_MASK_ALL,
104         [N_ONLINE] = { { [0] = 1UL } },
105 #ifndef CONFIG_NUMA
106         [N_NORMAL_MEMORY] = { { [0] = 1UL } },
107 #ifdef CONFIG_HIGHMEM
108         [N_HIGH_MEMORY] = { { [0] = 1UL } },
109 #endif
110 #ifdef CONFIG_MOVABLE_NODE
111         [N_MEMORY] = { { [0] = 1UL } },
112 #endif
113         [N_CPU] = { { [0] = 1UL } },
114 #endif  /* NUMA */
115 };
116 EXPORT_SYMBOL(node_states);
117 
118 /* Protect totalram_pages and zone->managed_pages */
119 static DEFINE_SPINLOCK(managed_page_count_lock);
120 
121 unsigned long totalram_pages __read_mostly;
122 unsigned long totalreserve_pages __read_mostly;
123 unsigned long totalcma_pages __read_mostly;
124 
125 int percpu_pagelist_fraction;
126 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
127 
128 /*
129  * A cached value of the page's pageblock's migratetype, used when the page is
130  * put on a pcplist. Used to avoid the pageblock migratetype lookup when
131  * freeing from pcplists in most cases, at the cost of possibly becoming stale.
132  * Also the migratetype set in the page does not necessarily match the pcplist
133  * index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
134  * other index - this ensures that it will be put on the correct CMA freelist.
135  */
136 static inline int get_pcppage_migratetype(struct page *page)
137 {
138         return page->index;
139 }
140 
141 static inline void set_pcppage_migratetype(struct page *page, int migratetype)
142 {
143         page->index = migratetype;
144 }
145 
146 #ifdef CONFIG_PM_SLEEP
147 /*
148  * The following functions are used by the suspend/hibernate code to temporarily
149  * change gfp_allowed_mask in order to avoid using I/O during memory allocations
150  * while devices are suspended.  To avoid races with the suspend/hibernate code,
151  * they should always be called with pm_mutex held (gfp_allowed_mask also should
152  * only be modified with pm_mutex held, unless the suspend/hibernate code is
153  * guaranteed not to run in parallel with that modification).
154  */
155 
156 static gfp_t saved_gfp_mask;
157 
158 void pm_restore_gfp_mask(void)
159 {
160         WARN_ON(!mutex_is_locked(&pm_mutex));
161         if (saved_gfp_mask) {
162                 gfp_allowed_mask = saved_gfp_mask;
163                 saved_gfp_mask = 0;
164         }
165 }
166 
167 void pm_restrict_gfp_mask(void)
168 {
169         WARN_ON(!mutex_is_locked(&pm_mutex));
170         WARN_ON(saved_gfp_mask);
171         saved_gfp_mask = gfp_allowed_mask;
172         gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
173 }
174 
175 bool pm_suspended_storage(void)
176 {
177         if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS))
178                 return false;
179         return true;
180 }
181 #endif /* CONFIG_PM_SLEEP */
182 
183 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
184 unsigned int pageblock_order __read_mostly;
185 #endif
186 
187 static void __free_pages_ok(struct page *page, unsigned int order);
188 
189 /*
190  * results with 256, 32 in the lowmem_reserve sysctl:
191  *      1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
192  *      1G machine -> (16M dma, 784M normal, 224M high)
193  *      NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
194  *      HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
195  *      HIGHMEM allocation will leave (224M+784M)/256 of ram reserved in ZONE_DMA
196  *
197  * TBD: should special case ZONE_DMA32 machines here - in those we normally
198  * don't need any ZONE_NORMAL reservation
199  */
200 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
201 #ifdef CONFIG_ZONE_DMA
202          256,
203 #endif
204 #ifdef CONFIG_ZONE_DMA32
205          256,
206 #endif
207 #ifdef CONFIG_HIGHMEM
208          32,
209 #endif
210          32,
211 };
212 
213 EXPORT_SYMBOL(totalram_pages);
214 
215 static char * const zone_names[MAX_NR_ZONES] = {
216 #ifdef CONFIG_ZONE_DMA
217          "DMA",
218 #endif
219 #ifdef CONFIG_ZONE_DMA32
220          "DMA32",
221 #endif
222          "Normal",
223 #ifdef CONFIG_HIGHMEM
224          "HighMem",
225 #endif
226          "Movable",
227 #ifdef CONFIG_ZONE_DEVICE
228          "Device",
229 #endif
230 };
231 
232 char * const migratetype_names[MIGRATE_TYPES] = {
233         "Unmovable",
234         "Movable",
235         "Reclaimable",
236         "HighAtomic",
237 #ifdef CONFIG_CMA
238         "CMA",
239 #endif
240 #ifdef CONFIG_MEMORY_ISOLATION
241         "Isolate",
242 #endif
243 };
244 
245 compound_page_dtor * const compound_page_dtors[] = {
246         NULL,
247         free_compound_page,
248 #ifdef CONFIG_HUGETLB_PAGE
249         free_huge_page,
250 #endif
251 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
252         free_transhuge_page,
253 #endif
254 };
255 
256 int min_free_kbytes = 1024;
257 int user_min_free_kbytes = -1;
258 int watermark_scale_factor = 10;
259 
260 static unsigned long __meminitdata nr_kernel_pages;
261 static unsigned long __meminitdata nr_all_pages;
262 static unsigned long __meminitdata dma_reserve;
263 
264 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
265 static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
266 static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
267 static unsigned long __initdata required_kernelcore;
268 static unsigned long __initdata required_movablecore;
269 static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
270 static bool mirrored_kernelcore;
271 
272 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
273 int movable_zone;
274 EXPORT_SYMBOL(movable_zone);
275 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
276 
277 #if MAX_NUMNODES > 1
278 int nr_node_ids __read_mostly = MAX_NUMNODES;
279 int nr_online_nodes __read_mostly = 1;
280 EXPORT_SYMBOL(nr_node_ids);
281 EXPORT_SYMBOL(nr_online_nodes);
282 #endif
283 
284 int page_group_by_mobility_disabled __read_mostly;
285 
286 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
287 static inline void reset_deferred_meminit(pg_data_t *pgdat)
288 {
289         pgdat->first_deferred_pfn = ULONG_MAX;
290 }
291 
292 /* Returns true if the struct page for the pfn is uninitialised */
293 static inline bool __meminit early_page_uninitialised(unsigned long pfn)
294 {
295         int nid = early_pfn_to_nid(pfn);
296 
297         if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn)
298                 return true;
299 
300         return false;
301 }
302 
303 /*
304  * Returns false when the remaining initialisation should be deferred until
305  * later in the boot cycle when it can be parallelised.
306  */
307 static inline bool update_defer_init(pg_data_t *pgdat,
308                                 unsigned long pfn, unsigned long zone_end,
309                                 unsigned long *nr_initialised)
310 {
311         unsigned long max_initialise;
312 
313         /* Always populate low zones for address-contrained allocations */
314         if (zone_end < pgdat_end_pfn(pgdat))
315                 return true;
316         /*
317          * Initialise at least 2G of a node but also take into account that
318          * two large system hashes that can take up 1GB for 0.25TB/node.
319          */
320         max_initialise = max(2UL << (30 - PAGE_SHIFT),
321                 (pgdat->node_spanned_pages >> 8));
322 
323         (*nr_initialised)++;
324         if ((*nr_initialised > max_initialise) &&
325             (pfn & (PAGES_PER_SECTION - 1)) == 0) {
326                 pgdat->first_deferred_pfn = pfn;
327                 return false;
328         }
329 
330         return true;
331 }
332 #else
333 static inline void reset_deferred_meminit(pg_data_t *pgdat)
334 {
335 }
336 
337 static inline bool early_page_uninitialised(unsigned long pfn)
338 {
339         return false;
340 }
341 
342 static inline bool update_defer_init(pg_data_t *pgdat,
343                                 unsigned long pfn, unsigned long zone_end,
344                                 unsigned long *nr_initialised)
345 {
346         return true;
347 }
348 #endif
349 
350 /* Return a pointer to the bitmap storing bits affecting a block of pages */
351 static inline unsigned long *get_pageblock_bitmap(struct page *page,
352                                                         unsigned long pfn)
353 {
354 #ifdef CONFIG_SPARSEMEM
355         return __pfn_to_section(pfn)->pageblock_flags;
356 #else
357         return page_zone(page)->pageblock_flags;
358 #endif /* CONFIG_SPARSEMEM */
359 }
360 
361 static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
362 {
363 #ifdef CONFIG_SPARSEMEM
364         pfn &= (PAGES_PER_SECTION-1);
365         return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
366 #else
367         pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
368         return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
369 #endif /* CONFIG_SPARSEMEM */
370 }
371 
372 /**
373  * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
374  * @page: The page within the block of interest
375  * @pfn: The target page frame number
376  * @end_bitidx: The last bit of interest to retrieve
377  * @mask: mask of bits that the caller is interested in
378  *
379  * Return: pageblock_bits flags
380  */
381 static __always_inline unsigned long __get_pfnblock_flags_mask(struct page *page,
382                                         unsigned long pfn,
383                                         unsigned long end_bitidx,
384                                         unsigned long mask)
385 {
386         unsigned long *bitmap;
387         unsigned long bitidx, word_bitidx;
388         unsigned long word;
389 
390         bitmap = get_pageblock_bitmap(page, pfn);
391         bitidx = pfn_to_bitidx(page, pfn);
392         word_bitidx = bitidx / BITS_PER_LONG;
393         bitidx &= (BITS_PER_LONG-1);
394 
395         word = bitmap[word_bitidx];
396         bitidx += end_bitidx;
397         return (word >> (BITS_PER_LONG - bitidx - 1)) & mask;
398 }
399 
400 unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
401                                         unsigned long end_bitidx,
402                                         unsigned long mask)
403 {
404         return __get_pfnblock_flags_mask(page, pfn, end_bitidx, mask);
405 }
406 
407 static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
408 {
409         return __get_pfnblock_flags_mask(page, pfn, PB_migrate_end, MIGRATETYPE_MASK);
410 }
411 
412 /**
413  * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
414  * @page: The page within the block of interest
415  * @flags: The flags to set
416  * @pfn: The target page frame number
417  * @end_bitidx: The last bit of interest
418  * @mask: mask of bits that the caller is interested in
419  */
420 void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
421                                         unsigned long pfn,
422                                         unsigned long end_bitidx,
423                                         unsigned long mask)
424 {
425         unsigned long *bitmap;
426         unsigned long bitidx, word_bitidx;
427         unsigned long old_word, word;
428 
429         BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
430 
431         bitmap = get_pageblock_bitmap(page, pfn);
432         bitidx = pfn_to_bitidx(page, pfn);
433         word_bitidx = bitidx / BITS_PER_LONG;
434         bitidx &= (BITS_PER_LONG-1);
435 
436         VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
437 
438         bitidx += end_bitidx;
439         mask <<= (BITS_PER_LONG - bitidx - 1);
440         flags <<= (BITS_PER_LONG - bitidx - 1);
441 
442         word = READ_ONCE(bitmap[word_bitidx]);
443         for (;;) {
444                 old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags);
445                 if (word == old_word)
446                         break;
447                 word = old_word;
448         }
449 }
450 
451 void set_pageblock_migratetype(struct page *page, int migratetype)
452 {
453         if (unlikely(page_group_by_mobility_disabled &&
454                      migratetype < MIGRATE_PCPTYPES))
455                 migratetype = MIGRATE_UNMOVABLE;
456 
457         set_pageblock_flags_group(page, (unsigned long)migratetype,
458                                         PB_migrate, PB_migrate_end);
459 }
460 
461 #ifdef CONFIG_DEBUG_VM
462 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
463 {
464         int ret = 0;
465         unsigned seq;
466         unsigned long pfn = page_to_pfn(page);
467         unsigned long sp, start_pfn;
468 
469         do {
470                 seq = zone_span_seqbegin(zone);
471                 start_pfn = zone->zone_start_pfn;
472                 sp = zone->spanned_pages;
473                 if (!zone_spans_pfn(zone, pfn))
474                         ret = 1;
475         } while (zone_span_seqretry(zone, seq));
476 
477         if (ret)
478                 pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
479                         pfn, zone_to_nid(zone), zone->name,
480                         start_pfn, start_pfn + sp);
481 
482         return ret;
483 }
484 
485 static int page_is_consistent(struct zone *zone, struct page *page)
486 {
487         if (!pfn_valid_within(page_to_pfn(page)))
488                 return 0;
489         if (zone != page_zone(page))
490                 return 0;
491 
492         return 1;
493 }
494 /*
495  * Temporary debugging check for pages not lying within a given zone.
496  */
497 static int bad_range(struct zone *zone, struct page *page)
498 {
499         if (page_outside_zone_boundaries(zone, page))
500                 return 1;
501         if (!page_is_consistent(zone, page))
502                 return 1;
503 
504         return 0;
505 }
506 #else
507 static inline int bad_range(struct zone *zone, struct page *page)
508 {
509         return 0;
510 }
511 #endif
512 
513 static void bad_page(struct page *page, const char *reason,
514                 unsigned long bad_flags)
515 {
516         static unsigned long resume;
517         static unsigned long nr_shown;
518         static unsigned long nr_unshown;
519 
520         /*
521          * Allow a burst of 60 reports, then keep quiet for that minute;
522          * or allow a steady drip of one report per second.
523          */
524         if (nr_shown == 60) {
525                 if (time_before(jiffies, resume)) {
526                         nr_unshown++;
527                         goto out;
528                 }
529                 if (nr_unshown) {
530                         pr_alert(
531                               "BUG: Bad page state: %lu messages suppressed\n",
532                                 nr_unshown);
533                         nr_unshown = 0;
534                 }
535                 nr_shown = 0;
536         }
537         if (nr_shown++ == 0)
538                 resume = jiffies + 60 * HZ;
539 
540         pr_alert("BUG: Bad page state in process %s  pfn:%05lx\n",
541                 current->comm, page_to_pfn(page));
542         __dump_page(page, reason);
543         bad_flags &= page->flags;
544         if (bad_flags)
545                 pr_alert("bad because of flags: %#lx(%pGp)\n",
546                                                 bad_flags, &bad_flags);
547         dump_page_owner(page);
548 
549         print_modules();
550         dump_stack();
551 out:
552         /* Leave bad fields for debug, except PageBuddy could make trouble */
553         page_mapcount_reset(page); /* remove PageBuddy */
554         add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
555 }
556 
557 /*
558  * Higher-order pages are called "compound pages".  They are structured thusly:
559  *
560  * The first PAGE_SIZE page is called the "head page" and have PG_head set.
561  *
562  * The remaining PAGE_SIZE pages are called "tail pages". PageTail() is encoded
563  * in bit 0 of page->compound_head. The rest of bits is pointer to head page.
564  *
565  * The first tail page's ->compound_dtor holds the offset in array of compound
566  * page destructors. See compound_page_dtors.
567  *
568  * The first tail page's ->compound_order holds the order of allocation.
569  * This usage means that zero-order pages may not be compound.
570  */
571 
572 void free_compound_page(struct page *page)
573 {
574         __free_pages_ok(page, compound_order(page));
575 }
576 
577 void prep_compound_page(struct page *page, unsigned int order)
578 {
579         int i;
580         int nr_pages = 1 << order;
581 
582         set_compound_page_dtor(page, COMPOUND_PAGE_DTOR);
583         set_compound_order(page, order);
584         __SetPageHead(page);
585         for (i = 1; i < nr_pages; i++) {
586                 struct page *p = page + i;
587                 set_page_count(p, 0);
588                 p->mapping = TAIL_MAPPING;
589                 set_compound_head(p, page);
590         }
591         atomic_set(compound_mapcount_ptr(page), -1);
592 }
593 
594 #ifdef CONFIG_DEBUG_PAGEALLOC
595 unsigned int _debug_guardpage_minorder;
596 bool _debug_pagealloc_enabled __read_mostly
597                         = IS_ENABLED(CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT);
598 EXPORT_SYMBOL(_debug_pagealloc_enabled);
599 bool _debug_guardpage_enabled __read_mostly;
600 
601 static int __init early_debug_pagealloc(char *buf)
602 {
603         if (!buf)
604                 return -EINVAL;
605         return kstrtobool(buf, &_debug_pagealloc_enabled);
606 }
607 early_param("debug_pagealloc", early_debug_pagealloc);
608 
609 static bool need_debug_guardpage(void)
610 {
611         /* If we don't use debug_pagealloc, we don't need guard page */
612         if (!debug_pagealloc_enabled())
613                 return false;
614 
615         if (!debug_guardpage_minorder())
616                 return false;
617 
618         return true;
619 }
620 
621 static void init_debug_guardpage(void)
622 {
623         if (!debug_pagealloc_enabled())
624                 return;
625 
626         if (!debug_guardpage_minorder())
627                 return;
628 
629         _debug_guardpage_enabled = true;
630 }
631 
632 struct page_ext_operations debug_guardpage_ops = {
633         .need = need_debug_guardpage,
634         .init = init_debug_guardpage,
635 };
636 
637 static int __init debug_guardpage_minorder_setup(char *buf)
638 {
639         unsigned long res;
640 
641         if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
642                 pr_err("Bad debug_guardpage_minorder value\n");
643                 return 0;
644         }
645         _debug_guardpage_minorder = res;
646         pr_info("Setting debug_guardpage_minorder to %lu\n", res);
647         return 0;
648 }
649 early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
650 
651 static inline bool set_page_guard(struct zone *zone, struct page *page,
652                                 unsigned int order, int migratetype)
653 {
654         struct page_ext *page_ext;
655 
656         if (!debug_guardpage_enabled())
657                 return false;
658 
659         if (order >= debug_guardpage_minorder())
660                 return false;
661 
662         page_ext = lookup_page_ext(page);
663         if (unlikely(!page_ext))
664                 return false;
665 
666         __set_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
667 
668         INIT_LIST_HEAD(&page->lru);
669         set_page_private(page, order);
670         /* Guard pages are not available for any usage */
671         __mod_zone_freepage_state(zone, -(1 << order), migratetype);
672 
673         return true;
674 }
675 
676 static inline void clear_page_guard(struct zone *zone, struct page *page,
677                                 unsigned int order, int migratetype)
678 {
679         struct page_ext *page_ext;
680 
681         if (!debug_guardpage_enabled())
682                 return;
683 
684         page_ext = lookup_page_ext(page);
685         if (unlikely(!page_ext))
686                 return;
687 
688         __clear_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
689 
690         set_page_private(page, 0);
691         if (!is_migrate_isolate(migratetype))
692                 __mod_zone_freepage_state(zone, (1 << order), migratetype);
693 }
694 #else
695 struct page_ext_operations debug_guardpage_ops;
696 static inline bool set_page_guard(struct zone *zone, struct page *page,
697                         unsigned int order, int migratetype) { return false; }
698 static inline void clear_page_guard(struct zone *zone, struct page *page,
699                                 unsigned int order, int migratetype) {}
700 #endif
701 
702 static inline void set_page_order(struct page *page, unsigned int order)
703 {
704         set_page_private(page, order);
705         __SetPageBuddy(page);
706 }
707 
708 static inline void rmv_page_order(struct page *page)
709 {
710         __ClearPageBuddy(page);
711         set_page_private(page, 0);
712 }
713 
714 /*
715  * This function checks whether a page is free && is the buddy
716  * we can do coalesce a page and its buddy if
717  * (a) the buddy is not in a hole &&
718  * (b) the buddy is in the buddy system &&
719  * (c) a page and its buddy have the same order &&
720  * (d) a page and its buddy are in the same zone.
721  *
722  * For recording whether a page is in the buddy system, we set ->_mapcount
723  * PAGE_BUDDY_MAPCOUNT_VALUE.
724  * Setting, clearing, and testing _mapcount PAGE_BUDDY_MAPCOUNT_VALUE is
725  * serialized by zone->lock.
726  *
727  * For recording page's order, we use page_private(page).
728  */
729 static inline int page_is_buddy(struct page *page, struct page *buddy,
730                                                         unsigned int order)
731 {
732         if (!pfn_valid_within(page_to_pfn(buddy)))
733                 return 0;
734 
735         if (page_is_guard(buddy) && page_order(buddy) == order) {
736                 if (page_zone_id(page) != page_zone_id(buddy))
737                         return 0;
738 
739                 VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
740 
741                 return 1;
742         }
743 
744         if (PageBuddy(buddy) && page_order(buddy) == order) {
745                 /*
746                  * zone check is done late to avoid uselessly
747                  * calculating zone/node ids for pages that could
748                  * never merge.
749                  */
750                 if (page_zone_id(page) != page_zone_id(buddy))
751                         return 0;
752 
753                 VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
754 
755                 return 1;
756         }
757         return 0;
758 }
759 
760 /*
761  * Freeing function for a buddy system allocator.
762  *
763  * The concept of a buddy system is to maintain direct-mapped table
764  * (containing bit values) for memory blocks of various "orders".
765  * The bottom level table contains the map for the smallest allocatable
766  * units of memory (here, pages), and each level above it describes
767  * pairs of units from the levels below, hence, "buddies".
768  * At a high level, all that happens here is marking the table entry
769  * at the bottom level available, and propagating the changes upward
770  * as necessary, plus some accounting needed to play nicely with other
771  * parts of the VM system.
772  * At each level, we keep a list of pages, which are heads of continuous
773  * free pages of length of (1 << order) and marked with _mapcount
774  * PAGE_BUDDY_MAPCOUNT_VALUE. Page's order is recorded in page_private(page)
775  * field.
776  * So when we are allocating or freeing one, we can derive the state of the
777  * other.  That is, if we allocate a small block, and both were
778  * free, the remainder of the region must be split into blocks.
779  * If a block is freed, and its buddy is also free, then this
780  * triggers coalescing into a block of larger size.
781  *
782  * -- nyc
783  */
784 
785 static inline void __free_one_page(struct page *page,
786                 unsigned long pfn,
787                 struct zone *zone, unsigned int order,
788                 int migratetype)
789 {
790         unsigned long page_idx;
791         unsigned long combined_idx;
792         unsigned long uninitialized_var(buddy_idx);
793         struct page *buddy;
794         unsigned int max_order;
795 
796         max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);
797 
798         VM_BUG_ON(!zone_is_initialized(zone));
799         VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
800 
801         VM_BUG_ON(migratetype == -1);
802         if (likely(!is_migrate_isolate(migratetype)))
803                 __mod_zone_freepage_state(zone, 1 << order, migratetype);
804 
805         page_idx = pfn & ((1 << MAX_ORDER) - 1);
806 
807         VM_BUG_ON_PAGE(page_idx & ((1 << order) - 1), page);
808         VM_BUG_ON_PAGE(bad_range(zone, page), page);
809 
810 continue_merging:
811         while (order < max_order - 1) {
812                 buddy_idx = __find_buddy_index(page_idx, order);
813                 buddy = page + (buddy_idx - page_idx);
814                 if (!page_is_buddy(page, buddy, order))
815                         goto done_merging;
816                 /*
817                  * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
818                  * merge with it and move up one order.
819                  */
820                 if (page_is_guard(buddy)) {
821                         clear_page_guard(zone, buddy, order, migratetype);
822                 } else {
823                         list_del(&buddy->lru);
824                         zone->free_area[order].nr_free--;
825                         rmv_page_order(buddy);
826                 }
827                 combined_idx = buddy_idx & page_idx;
828                 page = page + (combined_idx - page_idx);
829                 page_idx = combined_idx;
830                 order++;
831         }
832         if (max_order < MAX_ORDER) {
833                 /* If we are here, it means order is >= pageblock_order.
834                  * We want to prevent merge between freepages on isolate
835                  * pageblock and normal pageblock. Without this, pageblock
836                  * isolation could cause incorrect freepage or CMA accounting.
837                  *
838                  * We don't want to hit this code for the more frequent
839                  * low-order merging.
840                  */
841                 if (unlikely(has_isolate_pageblock(zone))) {
842                         int buddy_mt;
843 
844                         buddy_idx = __find_buddy_index(page_idx, order);
845                         buddy = page + (buddy_idx - page_idx);
846                         buddy_mt = get_pageblock_migratetype(buddy);
847 
848                         if (migratetype != buddy_mt
849                                         && (is_migrate_isolate(migratetype) ||
850                                                 is_migrate_isolate(buddy_mt)))
851                                 goto done_merging;
852                 }
853                 max_order++;
854                 goto continue_merging;
855         }
856 
857 done_merging:
858         set_page_order(page, order);
859 
860         /*
861          * If this is not the largest possible page, check if the buddy
862          * of the next-highest order is free. If it is, it's possible
863          * that pages are being freed that will coalesce soon. In case,
864          * that is happening, add the free page to the tail of the list
865          * so it's less likely to be used soon and more likely to be merged
866          * as a higher order page
867          */
868         if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
869                 struct page *higher_page, *higher_buddy;
870                 combined_idx = buddy_idx & page_idx;
871                 higher_page = page + (combined_idx - page_idx);
872                 buddy_idx = __find_buddy_index(combined_idx, order + 1);
873                 higher_buddy = higher_page + (buddy_idx - combined_idx);
874                 if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
875                         list_add_tail(&page->lru,
876                                 &zone->free_area[order].free_list[migratetype]);
877                         goto out;
878                 }
879         }
880 
881         list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
882 out:
883         zone->free_area[order].nr_free++;
884 }
885 
886 /*
887  * A bad page could be due to a number of fields. Instead of multiple branches,
888  * try and check multiple fields with one check. The caller must do a detailed
889  * check if necessary.
890  */
891 static inline bool page_expected_state(struct page *page,
892                                         unsigned long check_flags)
893 {
894         if (unlikely(atomic_read(&page->_mapcount) != -1))
895                 return false;
896 
897         if (unlikely((unsigned long)page->mapping |
898                         page_ref_count(page) |
899 #ifdef CONFIG_MEMCG
900                         (unsigned long)page->mem_cgroup |
901 #endif
902                         (page->flags & check_flags)))
903                 return false;
904 
905         return true;
906 }
907 
908 static void free_pages_check_bad(struct page *page)
909 {
910         const char *bad_reason;
911         unsigned long bad_flags;
912 
913         bad_reason = NULL;
914         bad_flags = 0;
915 
916         if (unlikely(atomic_read(&page->_mapcount) != -1))
917                 bad_reason = "nonzero mapcount";
918         if (unlikely(page->mapping != NULL))
919                 bad_reason = "non-NULL mapping";
920         if (unlikely(page_ref_count(page) != 0))
921                 bad_reason = "nonzero _refcount";
922         if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
923                 bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
924                 bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
925         }
926 #ifdef CONFIG_MEMCG
927         if (unlikely(page->mem_cgroup))
928                 bad_reason = "page still charged to cgroup";
929 #endif
930         bad_page(page, bad_reason, bad_flags);
931 }
932 
933 static inline int free_pages_check(struct page *page)
934 {
935         if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE)))
936                 return 0;
937 
938         /* Something has gone sideways, find it */
939         free_pages_check_bad(page);
940         return 1;
941 }
942 
943 static int free_tail_pages_check(struct page *head_page, struct page *page)
944 {
945         int ret = 1;
946 
947         /*
948          * We rely page->lru.next never has bit 0 set, unless the page
949          * is PageTail(). Let's make sure that's true even for poisoned ->lru.
950          */
951         BUILD_BUG_ON((unsigned long)LIST_POISON1 & 1);
952 
953         if (!IS_ENABLED(CONFIG_DEBUG_VM)) {
954                 ret = 0;
955                 goto out;
956         }
957         switch (page - head_page) {
958         case 1:
959                 /* the first tail page: ->mapping is compound_mapcount() */
960                 if (unlikely(compound_mapcount(page))) {
961                         bad_page(page, "nonzero compound_mapcount", 0);
962                         goto out;
963                 }
964                 break;
965         case 2:
966                 /*
967                  * the second tail page: ->mapping is
968                  * page_deferred_list().next -- ignore value.
969                  */
970                 break;
971         default:
972                 if (page->mapping != TAIL_MAPPING) {
973                         bad_page(page, "corrupted mapping in tail page", 0);
974                         goto out;
975                 }
976                 break;
977         }
978         if (unlikely(!PageTail(page))) {
979                 bad_page(page, "PageTail not set", 0);
980                 goto out;
981         }
982         if (unlikely(compound_head(page) != head_page)) {
983                 bad_page(page, "compound_head not consistent", 0);
984                 goto out;
985         }
986         ret = 0;
987 out:
988         page->mapping = NULL;
989         clear_compound_head(page);
990         return ret;
991 }
992 
993 static __always_inline bool free_pages_prepare(struct page *page,
994                                         unsigned int order, bool check_free)
995 {
996         int bad = 0;
997 
998         VM_BUG_ON_PAGE(PageTail(page), page);
999 
1000         trace_mm_page_free(page, order);
1001         kmemcheck_free_shadow(page, order);
1002 
1003         /*
1004          * Check tail pages before head page information is cleared to
1005          * avoid checking PageCompound for order-0 pages.
1006          */
1007         if (unlikely(order)) {
1008                 bool compound = PageCompound(page);
1009                 int i;
1010 
1011                 VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
1012 
1013                 if (compound)
1014                         ClearPageDoubleMap(page);
1015                 for (i = 1; i < (1 << order); i++) {
1016                         if (compound)
1017                                 bad += free_tail_pages_check(page, page + i);
1018                         if (unlikely(free_pages_check(page + i))) {
1019                                 bad++;
1020                                 continue;
1021                         }
1022                         (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1023                 }
1024         }
1025         if (PageMappingFlags(page))
1026                 page->mapping = NULL;
1027         if (memcg_kmem_enabled() && PageKmemcg(page))
1028                 memcg_kmem_uncharge(page, order);
1029         if (check_free)
1030                 bad += free_pages_check(page);
1031         if (bad)
1032                 return false;
1033 
1034         page_cpupid_reset_last(page);
1035         page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
1036         reset_page_owner(page, order);
1037 
1038         if (!PageHighMem(page)) {
1039                 debug_check_no_locks_freed(page_address(page),
1040                                            PAGE_SIZE << order);
1041                 debug_check_no_obj_freed(page_address(page),
1042                                            PAGE_SIZE << order);
1043         }
1044         arch_free_page(page, order);
1045         kernel_poison_pages(page, 1 << order, 0);
1046         kernel_map_pages(page, 1 << order, 0);
1047         kasan_free_pages(page, order);
1048 
1049         return true;
1050 }
1051 
1052 #ifdef CONFIG_DEBUG_VM
1053 static inline bool free_pcp_prepare(struct page *page)
1054 {
1055         return free_pages_prepare(page, 0, true);
1056 }
1057 
1058 static inline bool bulkfree_pcp_prepare(struct page *page)
1059 {
1060         return false;
1061 }
1062 #else
1063 static bool free_pcp_prepare(struct page *page)
1064 {
1065         return free_pages_prepare(page, 0, false);
1066 }
1067 
1068 static bool bulkfree_pcp_prepare(struct page *page)
1069 {
1070         return free_pages_check(page);
1071 }
1072 #endif /* CONFIG_DEBUG_VM */
1073 
1074 /*
1075  * Frees a number of pages from the PCP lists
1076  * Assumes all pages on list are in same zone, and of same order.
1077  * count is the number of pages to free.
1078  *
1079  * If the zone was previously in an "all pages pinned" state then look to
1080  * see if this freeing clears that state.
1081  *
1082  * And clear the zone's pages_scanned counter, to hold off the "all pages are
1083  * pinned" detection logic.
1084  */
1085 static void free_pcppages_bulk(struct zone *zone, int count,
1086                                         struct per_cpu_pages *pcp)
1087 {
1088         int migratetype = 0;
1089         int batch_free = 0;
1090         unsigned long nr_scanned;
1091         bool isolated_pageblocks;
1092 
1093         spin_lock(&zone->lock);
1094         isolated_pageblocks = has_isolate_pageblock(zone);
1095         nr_scanned = node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED);
1096         if (nr_scanned)
1097                 __mod_node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED, -nr_scanned);
1098 
1099         while (count) {
1100                 struct page *page;
1101                 struct list_head *list;
1102 
1103                 /*
1104                  * Remove pages from lists in a round-robin fashion. A
1105                  * batch_free count is maintained that is incremented when an
1106                  * empty list is encountered.  This is so more pages are freed
1107                  * off fuller lists instead of spinning excessively around empty
1108                  * lists
1109                  */
1110                 do {
1111                         batch_free++;
1112                         if (++migratetype == MIGRATE_PCPTYPES)
1113                                 migratetype = 0;
1114                         list = &pcp->lists[migratetype];
1115                 } while (list_empty(list));
1116 
1117                 /* This is the only non-empty list. Free them all. */
1118                 if (batch_free == MIGRATE_PCPTYPES)
1119                         batch_free = count;
1120 
1121                 do {
1122                         int mt; /* migratetype of the to-be-freed page */
1123 
1124                         page = list_last_entry(list, struct page, lru);
1125                         /* must delete as __free_one_page list manipulates */
1126                         list_del(&page->lru);
1127 
1128                         mt = get_pcppage_migratetype(page);
1129                         /* MIGRATE_ISOLATE page should not go to pcplists */
1130                         VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
1131                         /* Pageblock could have been isolated meanwhile */
1132                         if (unlikely(isolated_pageblocks))
1133                                 mt = get_pageblock_migratetype(page);
1134 
1135                         if (bulkfree_pcp_prepare(page))
1136                                 continue;
1137 
1138                         __free_one_page(page, page_to_pfn(page), zone, 0, mt);
1139                         trace_mm_page_pcpu_drain(page, 0, mt);
1140                 } while (--count && --batch_free && !list_empty(list));
1141         }
1142         spin_unlock(&zone->lock);
1143 }
1144 
1145 static void free_one_page(struct zone *zone,
1146                                 struct page *page, unsigned long pfn,
1147                                 unsigned int order,
1148                                 int migratetype)
1149 {
1150         unsigned long nr_scanned;
1151         spin_lock(&zone->lock);
1152         nr_scanned = node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED);
1153         if (nr_scanned)
1154                 __mod_node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED, -nr_scanned);
1155 
1156         if (unlikely(has_isolate_pageblock(zone) ||
1157                 is_migrate_isolate(migratetype))) {
1158                 migratetype = get_pfnblock_migratetype(page, pfn);
1159         }
1160         __free_one_page(page, pfn, zone, order, migratetype);
1161         spin_unlock(&zone->lock);
1162 }
1163 
1164 static void __meminit __init_single_page(struct page *page, unsigned long pfn,
1165                                 unsigned long zone, int nid)
1166 {
1167         set_page_links(page, zone, nid, pfn);
1168         init_page_count(page);
1169         page_mapcount_reset(page);
1170         page_cpupid_reset_last(page);
1171 
1172         INIT_LIST_HEAD(&page->lru);
1173 #ifdef WANT_PAGE_VIRTUAL
1174         /* The shift won't overflow because ZONE_NORMAL is below 4G. */
1175         if (!is_highmem_idx(zone))
1176                 set_page_address(page, __va(pfn << PAGE_SHIFT));
1177 #endif
1178 }
1179 
1180 static void __meminit __init_single_pfn(unsigned long pfn, unsigned long zone,
1181                                         int nid)
1182 {
1183         return __init_single_page(pfn_to_page(pfn), pfn, zone, nid);
1184 }
1185 
1186 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1187 static void init_reserved_page(unsigned long pfn)
1188 {
1189         pg_data_t *pgdat;
1190         int nid, zid;
1191 
1192         if (!early_page_uninitialised(pfn))
1193                 return;
1194 
1195         nid = early_pfn_to_nid(pfn);
1196         pgdat = NODE_DATA(nid);
1197 
1198         for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1199                 struct zone *zone = &pgdat->node_zones[zid];
1200 
1201                 if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
1202                         break;
1203         }
1204         __init_single_pfn(pfn, zid, nid);
1205 }
1206 #else
1207 static inline void init_reserved_page(unsigned long pfn)
1208 {
1209 }
1210 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1211 
1212 /*
1213  * Initialised pages do not have PageReserved set. This function is
1214  * called for each range allocated by the bootmem allocator and
1215  * marks the pages PageReserved. The remaining valid pages are later
1216  * sent to the buddy page allocator.
1217  */
1218 void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
1219 {
1220         unsigned long start_pfn = PFN_DOWN(start);
1221         unsigned long end_pfn = PFN_UP(end);
1222 
1223         for (; start_pfn < end_pfn; start_pfn++) {
1224                 if (pfn_valid(start_pfn)) {
1225                         struct page *page = pfn_to_page(start_pfn);
1226 
1227                         init_reserved_page(start_pfn);
1228 
1229                         /* Avoid false-positive PageTail() */
1230                         INIT_LIST_HEAD(&page->lru);
1231 
1232                         SetPageReserved(page);
1233                 }
1234         }
1235 }
1236 
1237 static void __free_pages_ok(struct page *page, unsigned int order)
1238 {
1239         unsigned long flags;
1240         int migratetype;
1241         unsigned long pfn = page_to_pfn(page);
1242 
1243         if (!free_pages_prepare(page, order, true))
1244                 return;
1245 
1246         migratetype = get_pfnblock_migratetype(page, pfn);
1247         local_irq_save(flags);
1248         __count_vm_events(PGFREE, 1 << order);
1249         free_one_page(page_zone(page), page, pfn, order, migratetype);
1250         local_irq_restore(flags);
1251 }
1252 
1253 static void __init __free_pages_boot_core(struct page *page, unsigned int order)
1254 {
1255         unsigned int nr_pages = 1 << order;
1256         struct page *p = page;
1257         unsigned int loop;
1258 
1259         prefetchw(p);
1260         for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
1261                 prefetchw(p + 1);
1262                 __ClearPageReserved(p);
1263                 set_page_count(p, 0);
1264         }
1265         __ClearPageReserved(p);
1266         set_page_count(p, 0);
1267 
1268         page_zone(page)->managed_pages += nr_pages;
1269         set_page_refcounted(page);
1270         __free_pages(page, order);
1271 }
1272 
1273 #if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \
1274         defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
1275 
1276 static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
1277 
1278 int __meminit early_pfn_to_nid(unsigned long pfn)
1279 {
1280         static DEFINE_SPINLOCK(early_pfn_lock);
1281         int nid;
1282 
1283         spin_lock(&early_pfn_lock);
1284         nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
1285         if (nid < 0)
1286                 nid = first_online_node;
1287         spin_unlock(&early_pfn_lock);
1288 
1289         return nid;
1290 }
1291 #endif
1292 
1293 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
1294 static inline bool __meminit meminit_pfn_in_nid(unsigned long pfn, int node,
1295                                         struct mminit_pfnnid_cache *state)
1296 {
1297         int nid;
1298 
1299         nid = __early_pfn_to_nid(pfn, state);
1300         if (nid >= 0 && nid != node)
1301                 return false;
1302         return true;
1303 }
1304 
1305 /* Only safe to use early in boot when initialisation is single-threaded */
1306 static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
1307 {
1308         return meminit_pfn_in_nid(pfn, node, &early_pfnnid_cache);
1309 }
1310 
1311 #else
1312 
1313 static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
1314 {
1315         return true;
1316 }
1317 static inline bool __meminit meminit_pfn_in_nid(unsigned long pfn, int node,
1318                                         struct mminit_pfnnid_cache *state)
1319 {
1320         return true;
1321 }
1322 #endif
1323 
1324 
1325 void __init __free_pages_bootmem(struct page *page, unsigned long pfn,
1326                                                         unsigned int order)
1327 {
1328         if (early_page_uninitialised(pfn))
1329                 return;
1330         return __free_pages_boot_core(page, order);
1331 }
1332 
1333 /*
1334  * Check that the whole (or subset of) a pageblock given by the interval of
1335  * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
1336  * with the migration of free compaction scanner. The scanners then need to
1337  * use only pfn_valid_within() check for arches that allow holes within
1338  * pageblocks.
1339  *
1340  * Return struct page pointer of start_pfn, or NULL if checks were not passed.
1341  *
1342  * It's possible on some configurations to have a setup like node0 node1 node0
1343  * i.e. it's possible that all pages within a zones range of pages do not
1344  * belong to a single zone. We assume that a border between node0 and node1
1345  * can occur within a single pageblock, but not a node0 node1 node0
1346  * interleaving within a single pageblock. It is therefore sufficient to check
1347  * the first and last page of a pageblock and avoid checking each individual
1348  * page in a pageblock.
1349  */
1350 struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
1351                                      unsigned long end_pfn, struct zone *zone)
1352 {
1353         struct page *start_page;
1354         struct page *end_page;
1355 
1356         /* end_pfn is one past the range we are checking */
1357         end_pfn--;
1358 
1359         if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
1360                 return NULL;
1361 
1362         start_page = pfn_to_page(start_pfn);
1363 
1364         if (page_zone(start_page) != zone)
1365                 return NULL;
1366 
1367         end_page = pfn_to_page(end_pfn);
1368 
1369         /* This gives a shorter code than deriving page_zone(end_page) */
1370         if (page_zone_id(start_page) != page_zone_id(end_page))
1371                 return NULL;
1372 
1373         return start_page;
1374 }
1375 
1376 void set_zone_contiguous(struct zone *zone)
1377 {
1378         unsigned long block_start_pfn = zone->zone_start_pfn;
1379         unsigned long block_end_pfn;
1380 
1381         block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages);
1382         for (; block_start_pfn < zone_end_pfn(zone);
1383                         block_start_pfn = block_end_pfn,
1384                          block_end_pfn += pageblock_nr_pages) {
1385 
1386                 block_end_pfn = min(block_end_pfn, zone_end_pfn(zone));
1387 
1388                 if (!__pageblock_pfn_to_page(block_start_pfn,
1389                                              block_end_pfn, zone))
1390                         return;
1391         }
1392 
1393         /* We confirm that there is no hole */
1394         zone->contiguous = true;
1395 }
1396 
1397 void clear_zone_contiguous(struct zone *zone)
1398 {
1399         zone->contiguous = false;
1400 }
1401 
1402 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1403 static void __init deferred_free_range(struct page *page,
1404                                         unsigned long pfn, int nr_pages)
1405 {
1406         int i;
1407 
1408         if (!page)
1409                 return;
1410 
1411         /* Free a large naturally-aligned chunk if possible */
1412         if (nr_pages == pageblock_nr_pages &&
1413             (pfn & (pageblock_nr_pages - 1)) == 0) {
1414                 set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1415                 __free_pages_boot_core(page, pageblock_order);
1416                 return;
1417         }
1418 
1419         for (i = 0; i < nr_pages; i++, page++, pfn++) {
1420                 if ((pfn & (pageblock_nr_pages - 1)) == 0)
1421                         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1422                 __free_pages_boot_core(page, 0);
1423         }
1424 }
1425 
1426 /* Completion tracking for deferred_init_memmap() threads */
1427 static atomic_t pgdat_init_n_undone __initdata;
1428 static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp);
1429 
1430 static inline void __init pgdat_init_report_one_done(void)
1431 {
1432         if (atomic_dec_and_test(&pgdat_init_n_undone))
1433                 complete(&pgdat_init_all_done_comp);
1434 }
1435 
1436 /* Initialise remaining memory on a node */
1437 static int __init deferred_init_memmap(void *data)
1438 {
1439         pg_data_t *pgdat = data;
1440         int nid = pgdat->node_id;
1441         struct mminit_pfnnid_cache nid_init_state = { };
1442         unsigned long start = jiffies;
1443         unsigned long nr_pages = 0;
1444         unsigned long walk_start, walk_end;
1445         int i, zid;
1446         struct zone *zone;
1447         unsigned long first_init_pfn = pgdat->first_deferred_pfn;
1448         const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
1449 
1450         if (first_init_pfn == ULONG_MAX) {
1451                 pgdat_init_report_one_done();
1452                 return 0;
1453         }
1454 
1455         /* Bind memory initialisation thread to a local node if possible */
1456         if (!cpumask_empty(cpumask))
1457                 set_cpus_allowed_ptr(current, cpumask);
1458 
1459         /* Sanity check boundaries */
1460         BUG_ON(pgdat->first_deferred_pfn < pgdat->node_start_pfn);
1461         BUG_ON(pgdat->first_deferred_pfn > pgdat_end_pfn(pgdat));
1462         pgdat->first_deferred_pfn = ULONG_MAX;
1463 
1464         /* Only the highest zone is deferred so find it */
1465         for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1466                 zone = pgdat->node_zones + zid;
1467                 if (first_init_pfn < zone_end_pfn(zone))
1468                         break;
1469         }
1470 
1471         for_each_mem_pfn_range(i, nid, &walk_start, &walk_end, NULL) {
1472                 unsigned long pfn, end_pfn;
1473                 struct page *page = NULL;
1474                 struct page *free_base_page = NULL;
1475                 unsigned long free_base_pfn = 0;
1476                 int nr_to_free = 0;
1477 
1478                 end_pfn = min(walk_end, zone_end_pfn(zone));
1479                 pfn = first_init_pfn;
1480                 if (pfn < walk_start)
1481                         pfn = walk_start;
1482                 if (pfn < zone->zone_start_pfn)
1483                         pfn = zone->zone_start_pfn;
1484 
1485                 for (; pfn < end_pfn; pfn++) {
1486                         if (!pfn_valid_within(pfn))
1487                                 goto free_range;
1488 
1489                         /*
1490                          * Ensure pfn_valid is checked every
1491                          * pageblock_nr_pages for memory holes
1492                          */
1493                         if ((pfn & (pageblock_nr_pages - 1)) == 0) {
1494                                 if (!pfn_valid(pfn)) {
1495                                         page = NULL;
1496                                         goto free_range;
1497                                 }
1498                         }
1499 
1500                         if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state)) {
1501                                 page = NULL;
1502                                 goto free_range;
1503                         }
1504 
1505                         /* Minimise pfn page lookups and scheduler checks */
1506                         if (page && (pfn & (pageblock_nr_pages - 1)) != 0) {
1507                                 page++;
1508                         } else {
1509                                 nr_pages += nr_to_free;
1510                                 deferred_free_range(free_base_page,
1511                                                 free_base_pfn, nr_to_free);
1512                                 free_base_page = NULL;
1513                                 free_base_pfn = nr_to_free = 0;
1514 
1515                                 page = pfn_to_page(pfn);
1516                                 cond_resched();
1517                         }
1518 
1519                         if (page->flags) {
1520                                 VM_BUG_ON(page_zone(page) != zone);
1521                                 goto free_range;
1522                         }
1523 
1524                         __init_single_page(page, pfn, zid, nid);
1525                         if (!free_base_page) {
1526                                 free_base_page = page;
1527                                 free_base_pfn = pfn;
1528                                 nr_to_free = 0;
1529                         }
1530                         nr_to_free++;
1531 
1532                         /* Where possible, batch up pages for a single free */
1533                         continue;
1534 free_range:
1535                         /* Free the current block of pages to allocator */
1536                         nr_pages += nr_to_free;
1537                         deferred_free_range(free_base_page, free_base_pfn,
1538                                                                 nr_to_free);
1539                         free_base_page = NULL;
1540                         free_base_pfn = nr_to_free = 0;
1541                 }
1542                 /* Free the last block of pages to allocator */
1543                 nr_pages += nr_to_free;
1544                 deferred_free_range(free_base_page, free_base_pfn, nr_to_free);
1545 
1546                 first_init_pfn = max(end_pfn, first_init_pfn);
1547         }
1548 
1549         /* Sanity check that the next zone really is unpopulated */
1550         WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));
1551 
1552         pr_info("node %d initialised, %lu pages in %ums\n", nid, nr_pages,
1553                                         jiffies_to_msecs(jiffies - start));
1554 
1555         pgdat_init_report_one_done();
1556         return 0;
1557 }
1558 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1559 
1560 void __init page_alloc_init_late(void)
1561 {
1562         struct zone *zone;
1563 
1564 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1565         int nid;
1566 
1567         /* There will be num_node_state(N_MEMORY) threads */
1568         atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY));
1569         for_each_node_state(nid, N_MEMORY) {
1570                 kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid);
1571         }
1572 
1573         /* Block until all are initialised */
1574         wait_for_completion(&pgdat_init_all_done_comp);
1575 
1576         /* Reinit limits that are based on free pages after the kernel is up */
1577         files_maxfiles_init();
1578 #endif
1579 
1580         for_each_populated_zone(zone)
1581                 set_zone_contiguous(zone);
1582 }
1583 
1584 #ifdef CONFIG_CMA
1585 /* Free whole pageblock and set its migration type to MIGRATE_CMA. */
1586 void __init init_cma_reserved_pageblock(struct page *page)
1587 {
1588         unsigned i = pageblock_nr_pages;
1589         struct page *p = page;
1590 
1591         do {
1592                 __ClearPageReserved(p);
1593                 set_page_count(p, 0);
1594         } while (++p, --i);
1595 
1596         set_pageblock_migratetype(page, MIGRATE_CMA);
1597 
1598         if (pageblock_order >= MAX_ORDER) {
1599                 i = pageblock_nr_pages;
1600                 p = page;
1601                 do {
1602                         set_page_refcounted(p);
1603                         __free_pages(p, MAX_ORDER - 1);
1604                         p += MAX_ORDER_NR_PAGES;
1605                 } while (i -= MAX_ORDER_NR_PAGES);
1606         } else {
1607                 set_page_refcounted(page);
1608                 __free_pages(page, pageblock_order);
1609         }
1610 
1611         adjust_managed_page_count(page, pageblock_nr_pages);
1612 }
1613 #endif
1614 
1615 /*
1616  * The order of subdivision here is critical for the IO subsystem.
1617  * Please do not alter this order without good reasons and regression
1618  * testing. Specifically, as large blocks of memory are subdivided,
1619  * the order in which smaller blocks are delivered depends on the order
1620  * they're subdivided in this function. This is the primary factor
1621  * influencing the order in which pages are delivered to the IO
1622  * subsystem according to empirical testing, and this is also justified
1623  * by considering the behavior of a buddy system containing a single
1624  * large block of memory acted on by a series of small allocations.
1625  * This behavior is a critical factor in sglist merging's success.
1626  *
1627  * -- nyc
1628  */
1629 static inline void expand(struct zone *zone, struct page *page,
1630         int low, int high, struct free_area *area,
1631         int migratetype)
1632 {
1633         unsigned long size = 1 << high;
1634 
1635         while (high > low) {
1636                 area--;
1637                 high--;
1638                 size >>= 1;
1639                 VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
1640 
1641                 /*
1642                  * Mark as guard pages (or page), that will allow to
1643                  * merge back to allocator when buddy will be freed.
1644                  * Corresponding page table entries will not be touched,
1645                  * pages will stay not present in virtual address space
1646                  */
1647                 if (set_page_guard(zone, &page[size], high, migratetype))
1648                         continue;
1649 
1650                 list_add(&page[size].lru, &area->free_list[migratetype]);
1651                 area->nr_free++;
1652                 set_page_order(&page[size], high);
1653         }
1654 }
1655 
1656 static void check_new_page_bad(struct page *page)
1657 {
1658         const char *bad_reason = NULL;
1659         unsigned long bad_flags = 0;
1660 
1661         if (unlikely(atomic_read(&page->_mapcount) != -1))
1662                 bad_reason = "nonzero mapcount";
1663         if (unlikely(page->mapping != NULL))
1664                 bad_reason = "non-NULL mapping";
1665         if (unlikely(page_ref_count(page) != 0))
1666                 bad_reason = "nonzero _count";
1667         if (unlikely(page->flags & __PG_HWPOISON)) {
1668                 bad_reason = "HWPoisoned (hardware-corrupted)";
1669                 bad_flags = __PG_HWPOISON;
1670                 /* Don't complain about hwpoisoned pages */
1671                 page_mapcount_reset(page); /* remove PageBuddy */
1672                 return;
1673         }
1674         if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
1675                 bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
1676                 bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
1677         }
1678 #ifdef CONFIG_MEMCG
1679         if (unlikely(page->mem_cgroup))
1680                 bad_reason = "page still charged to cgroup";
1681 #endif
1682         bad_page(page, bad_reason, bad_flags);
1683 }
1684 
1685 /*
1686  * This page is about to be returned from the page allocator
1687  */
1688 static inline int check_new_page(struct page *page)
1689 {
1690         if (likely(page_expected_state(page,
1691                                 PAGE_FLAGS_CHECK_AT_PREP|__PG_HWPOISON)))
1692                 return 0;
1693 
1694         check_new_page_bad(page);
1695         return 1;
1696 }
1697 
1698 static inline bool free_pages_prezeroed(bool poisoned)
1699 {
1700         return IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) &&
1701                 page_poisoning_enabled() && poisoned;
1702 }
1703 
1704 #ifdef CONFIG_DEBUG_VM
1705 static bool check_pcp_refill(struct page *page)
1706 {
1707         return false;
1708 }
1709 
1710 static bool check_new_pcp(struct page *page)
1711 {
1712         return check_new_page(page);
1713 }
1714 #else
1715 static bool check_pcp_refill(struct page *page)
1716 {
1717         return check_new_page(page);
1718 }
1719 static bool check_new_pcp(struct page *page)
1720 {
1721         return false;
1722 }
1723 #endif /* CONFIG_DEBUG_VM */
1724 
1725 static bool check_new_pages(struct page *page, unsigned int order)
1726 {
1727         int i;
1728         for (i = 0; i < (1 << order); i++) {
1729                 struct page *p = page + i;
1730 
1731                 if (unlikely(check_new_page(p)))
1732                         return true;
1733         }
1734 
1735         return false;
1736 }
1737 
1738 inline void post_alloc_hook(struct page *page, unsigned int order,
1739                                 gfp_t gfp_flags)
1740 {
1741         set_page_private(page, 0);
1742         set_page_refcounted(page);
1743 
1744         arch_alloc_page(page, order);
1745         kernel_map_pages(page, 1 << order, 1);
1746         kernel_poison_pages(page, 1 << order, 1);
1747         kasan_alloc_pages(page, order);
1748         set_page_owner(page, order, gfp_flags);
1749 }
1750 
1751 static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
1752                                                         unsigned int alloc_flags)
1753 {
1754         int i;
1755         bool poisoned = true;
1756 
1757         for (i = 0; i < (1 << order); i++) {
1758                 struct page *p = page + i;
1759                 if (poisoned)
1760                         poisoned &= page_is_poisoned(p);
1761         }
1762 
1763         post_alloc_hook(page, order, gfp_flags);
1764 
1765         if (!free_pages_prezeroed(poisoned) && (gfp_flags & __GFP_ZERO))
1766                 for (i = 0; i < (1 << order); i++)
1767                         clear_highpage(page + i);
1768 
1769         if (order && (gfp_flags & __GFP_COMP))
1770                 prep_compound_page(page, order);
1771 
1772         /*
1773          * page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
1774          * allocate the page. The expectation is that the caller is taking
1775          * steps that will free more memory. The caller should avoid the page
1776          * being used for !PFMEMALLOC purposes.
1777          */
1778         if (alloc_flags & ALLOC_NO_WATERMARKS)
1779                 set_page_pfmemalloc(page);
1780         else
1781                 clear_page_pfmemalloc(page);
1782 }
1783 
1784 /*
1785  * Go through the free lists for the given migratetype and remove
1786  * the smallest available page from the freelists
1787  */
1788 static inline
1789 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
1790                                                 int migratetype)
1791 {
1792         unsigned int current_order;
1793         struct free_area *area;
1794         struct page *page;
1795 
1796         /* Find a page of the appropriate size in the preferred list */
1797         for (current_order = order; current_order < MAX_ORDER; ++current_order) {
1798                 area = &(zone->free_area[current_order]);
1799                 page = list_first_entry_or_null(&area->free_list[migratetype],
1800                                                         struct page, lru);
1801                 if (!page)
1802                         continue;
1803                 list_del(&page->lru);
1804                 rmv_page_order(page);
1805                 area->nr_free--;
1806                 expand(zone, page, order, current_order, area, migratetype);
1807                 set_pcppage_migratetype(page, migratetype);
1808                 return page;
1809         }
1810 
1811         return NULL;
1812 }
1813 
1814 
1815 /*
1816  * This array describes the order lists are fallen back to when
1817  * the free lists for the desirable migrate type are depleted
1818  */
1819 static int fallbacks[MIGRATE_TYPES][4] = {
1820         [MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_TYPES },
1821         [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_TYPES },
1822         [MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
1823 #ifdef CONFIG_CMA
1824         [MIGRATE_CMA]         = { MIGRATE_TYPES }, /* Never used */
1825 #endif
1826 #ifdef CONFIG_MEMORY_ISOLATION
1827         [MIGRATE_ISOLATE]     = { MIGRATE_TYPES }, /* Never used */
1828 #endif
1829 };
1830 
1831 #ifdef CONFIG_CMA
1832 static struct page *__rmqueue_cma_fallback(struct zone *zone,
1833                                         unsigned int order)
1834 {
1835         return __rmqueue_smallest(zone, order, MIGRATE_CMA);
1836 }
1837 #else
1838 static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
1839                                         unsigned int order) { return NULL; }
1840 #endif
1841 
1842 /*
1843  * Move the free pages in a range to the free lists of the requested type.
1844  * Note that start_page and end_pages are not aligned on a pageblock
1845  * boundary. If alignment is required, use move_freepages_block()
1846  */
1847 int move_freepages(struct zone *zone,
1848                           struct page *start_page, struct page *end_page,
1849                           int migratetype)
1850 {
1851         struct page *page;
1852         unsigned int order;
1853         int pages_moved = 0;
1854 
1855 #ifndef CONFIG_HOLES_IN_ZONE
1856         /*
1857          * page_zone is not safe to call in this context when
1858          * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
1859          * anyway as we check zone boundaries in move_freepages_block().
1860          * Remove at a later date when no bug reports exist related to
1861          * grouping pages by mobility
1862          */
1863         VM_BUG_ON(page_zone(start_page) != page_zone(end_page));
1864 #endif
1865 
1866         for (page = start_page; page <= end_page;) {
1867                 /* Make sure we are not inadvertently changing nodes */
1868                 VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
1869 
1870                 if (!pfn_valid_within(page_to_pfn(page))) {
1871                         page++;
1872                         continue;
1873                 }
1874 
1875                 if (!PageBuddy(page)) {
1876                         page++;
1877                         continue;
1878                 }
1879 
1880                 order = page_order(page);
1881                 list_move(&page->lru,
1882                           &zone->free_area[order].free_list[migratetype]);
1883                 page += 1 << order;
1884                 pages_moved += 1 << order;
1885         }
1886 
1887         return pages_moved;
1888 }
1889 
1890 int move_freepages_block(struct zone *zone, struct page *page,
1891                                 int migratetype)
1892 {
1893         unsigned long start_pfn, end_pfn;
1894         struct page *start_page, *end_page;
1895 
1896         start_pfn = page_to_pfn(page);
1897         start_pfn = start_pfn & ~(pageblock_nr_pages-1);
1898         start_page = pfn_to_page(start_pfn);
1899         end_page = start_page + pageblock_nr_pages - 1;
1900         end_pfn = start_pfn + pageblock_nr_pages - 1;
1901 
1902         /* Do not cross zone boundaries */
1903         if (!zone_spans_pfn(zone, start_pfn))
1904                 start_page = page;
1905         if (!zone_spans_pfn(zone, end_pfn))
1906                 return 0;
1907 
1908         return move_freepages(zone, start_page, end_page, migratetype);
1909 }
1910 
1911 static void change_pageblock_range(struct page *pageblock_page,
1912                                         int start_order, int migratetype)
1913 {
1914         int nr_pageblocks = 1 << (start_order - pageblock_order);
1915 
1916         while (nr_pageblocks--) {
1917                 set_pageblock_migratetype(pageblock_page, migratetype);
1918                 pageblock_page += pageblock_nr_pages;
1919         }
1920 }
1921 
1922 /*
1923  * When we are falling back to another migratetype during allocation, try to
1924  * steal extra free pages from the same pageblocks to satisfy further
1925  * allocations, instead of polluting multiple pageblocks.
1926  *
1927  * If we are stealing a relatively large buddy page, it is likely there will
1928  * be more free pages in the pageblock, so try to steal them all. For
1929  * reclaimable and unmovable allocations, we steal regardless of page size,
1930  * as fragmentation caused by those allocations polluting movable pageblocks
1931  * is worse than movable allocations stealing from unmovable and reclaimable
1932  * pageblocks.
1933  */
1934 static bool can_steal_fallback(unsigned int order, int start_mt)
1935 {
1936         /*
1937          * Leaving this order check is intended, although there is
1938          * relaxed order check in next check. The reason is that
1939          * we can actually steal whole pageblock if this condition met,
1940          * but, below check doesn't guarantee it and that is just heuristic
1941          * so could be changed anytime.
1942          */
1943         if (order >= pageblock_order)
1944                 return true;
1945 
1946         if (order >= pageblock_order / 2 ||
1947                 start_mt == MIGRATE_RECLAIMABLE ||
1948                 start_mt == MIGRATE_UNMOVABLE ||
1949                 page_group_by_mobility_disabled)
1950                 return true;
1951 
1952         return false;
1953 }
1954 
1955 /*
1956  * This function implements actual steal behaviour. If order is large enough,
1957  * we can steal whole pageblock. If not, we first move freepages in this
1958  * pageblock and check whether half of pages are moved or not. If half of
1959  * pages are moved, we can change migratetype of pageblock and permanently
1960  * use it's pages as requested migratetype in the future.
1961  */
1962 static void steal_suitable_fallback(struct zone *zone, struct page *page,
1963                                                           int start_type)
1964 {
1965         unsigned int current_order = page_order(page);
1966         int pages;
1967 
1968         /* Take ownership for orders >= pageblock_order */
1969         if (current_order >= pageblock_order) {
1970                 change_pageblock_range(page, current_order, start_type);
1971                 return;
1972         }
1973 
1974         pages = move_freepages_block(zone, page, start_type);
1975 
1976         /* Claim the whole block if over half of it is free */
1977         if (pages >= (1 << (pageblock_order-1)) ||
1978                         page_group_by_mobility_disabled)
1979                 set_pageblock_migratetype(page, start_type);
1980 }
1981 
1982 /*
1983  * Check whether there is a suitable fallback freepage with requested order.
1984  * If only_stealable is true, this function returns fallback_mt only if
1985  * we can steal other freepages all together. This would help to reduce
1986  * fragmentation due to mixed migratetype pages in one pageblock.
1987  */
1988 int find_suitable_fallback(struct free_area *area, unsigned int order,
1989                         int migratetype, bool only_stealable, bool *can_steal)
1990 {
1991         int i;
1992         int fallback_mt;
1993 
1994         if (area->nr_free == 0)
1995                 return -1;
1996 
1997         *can_steal = false;
1998         for (i = 0;; i++) {
1999                 fallback_mt = fallbacks[migratetype][i];
2000                 if (fallback_mt == MIGRATE_TYPES)
2001                         break;
2002 
2003                 if (list_empty(&area->free_list[fallback_mt]))
2004                         continue;
2005 
2006                 if (can_steal_fallback(order, migratetype))
2007                         *can_steal = true;
2008 
2009                 if (!only_stealable)
2010                         return fallback_mt;
2011 
2012                 if (*can_steal)
2013                         return fallback_mt;
2014         }
2015 
2016         return -1;
2017 }
2018 
2019 /*
2020  * Reserve a pageblock for exclusive use of high-order atomic allocations if
2021  * there are no empty page blocks that contain a page with a suitable order
2022  */
2023 static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
2024                                 unsigned int alloc_order)
2025 {
2026         int mt;
2027         unsigned long max_managed, flags;
2028 
2029         /*
2030          * Limit the number reserved to 1 pageblock or roughly 1% of a zone.
2031          * Check is race-prone but harmless.
2032          */
2033         max_managed = (zone->managed_pages / 100) + pageblock_nr_pages;
2034         if (zone->nr_reserved_highatomic >= max_managed)
2035                 return;
2036 
2037         spin_lock_irqsave(&zone->lock, flags);
2038 
2039         /* Recheck the nr_reserved_highatomic limit under the lock */
2040         if (zone->nr_reserved_highatomic >= max_managed)
2041                 goto out_unlock;
2042 
2043         /* Yoink! */
2044         mt = get_pageblock_migratetype(page);
2045         if (mt != MIGRATE_HIGHATOMIC &&
2046                         !is_migrate_isolate(mt) && !is_migrate_cma(mt)) {
2047                 zone->nr_reserved_highatomic += pageblock_nr_pages;
2048                 set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
2049                 move_freepages_block(zone, page, MIGRATE_HIGHATOMIC);
2050         }
2051 
2052 out_unlock:
2053         spin_unlock_irqrestore(&zone->lock, flags);
2054 }
2055 
2056 /*
2057  * Used when an allocation is about to fail under memory pressure. This
2058  * potentially hurts the reliability of high-order allocations when under
2059  * intense memory pressure but failed atomic allocations should be easier
2060  * to recover from than an OOM.
2061  */
2062 static void unreserve_highatomic_pageblock(const struct alloc_context *ac)
2063 {
2064         struct zonelist *zonelist = ac->zonelist;
2065         unsigned long flags;
2066         struct zoneref *z;
2067         struct zone *zone;
2068         struct page *page;
2069         int order;
2070 
2071         for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->high_zoneidx,
2072                                                                 ac->nodemask) {
2073                 /* Preserve at least one pageblock */
2074                 if (zone->nr_reserved_highatomic <= pageblock_nr_pages)
2075                         continue;
2076 
2077                 spin_lock_irqsave(&zone->lock, flags);
2078                 for (order = 0; order < MAX_ORDER; order++) {
2079                         struct free_area *area = &(zone->free_area[order]);
2080 
2081                         page = list_first_entry_or_null(
2082                                         &area->free_list[MIGRATE_HIGHATOMIC],
2083                                         struct page, lru);
2084                         if (!page)
2085                                 continue;
2086 
2087                         /*
2088                          * It should never happen but changes to locking could
2089                          * inadvertently allow a per-cpu drain to add pages
2090                          * to MIGRATE_HIGHATOMIC while unreserving so be safe
2091                          * and watch for underflows.
2092                          */
2093                         zone->nr_reserved_highatomic -= min(pageblock_nr_pages,
2094                                 zone->nr_reserved_highatomic);
2095 
2096                         /*
2097                          * Convert to ac->migratetype and avoid the normal
2098                          * pageblock stealing heuristics. Minimally, the caller
2099                          * is doing the work and needs the pages. More
2100                          * importantly, if the block was always converted to
2101                          * MIGRATE_UNMOVABLE or another type then the number
2102                          * of pageblocks that cannot be completely freed
2103                          * may increase.
2104                          */
2105                         set_pageblock_migratetype(page, ac->migratetype);
2106                         move_freepages_block(zone, page, ac->migratetype);
2107                         spin_unlock_irqrestore(&zone->lock, flags);
2108                         return;
2109                 }
2110                 spin_unlock_irqrestore(&zone->lock, flags);
2111         }
2112 }
2113 
2114 /* Remove an element from the buddy allocator from the fallback list */
2115 static inline struct page *
2116 __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype)
2117 {
2118         struct free_area *area;
2119         unsigned int current_order;
2120         struct page *page;
2121         int fallback_mt;
2122         bool can_steal;
2123 
2124         /* Find the largest possible block of pages in the other list */
2125         for (current_order = MAX_ORDER-1;
2126                                 current_order >= order && current_order <= MAX_ORDER-1;
2127                                 --current_order) {
2128                 area = &(zone->free_area[current_order]);
2129                 fallback_mt = find_suitable_fallback(area, current_order,
2130                                 start_migratetype, false, &can_steal);
2131                 if (fallback_mt == -1)
2132                         continue;
2133 
2134                 page = list_first_entry(&area->free_list[fallback_mt],
2135                                                 struct page, lru);
2136                 if (can_steal)
2137                         steal_suitable_fallback(zone, page, start_migratetype);
2138 
2139                 /* Remove the page from the freelists */
2140                 area->nr_free--;
2141                 list_del(&page->lru);
2142                 rmv_page_order(page);
2143 
2144                 expand(zone, page, order, current_order, area,
2145                                         start_migratetype);
2146                 /*
2147                  * The pcppage_migratetype may differ from pageblock's
2148                  * migratetype depending on the decisions in
2149                  * find_suitable_fallback(). This is OK as long as it does not
2150                  * differ for MIGRATE_CMA pageblocks. Those can be used as
2151                  * fallback only via special __rmqueue_cma_fallback() function
2152                  */
2153                 set_pcppage_migratetype(page, start_migratetype);
2154 
2155                 trace_mm_page_alloc_extfrag(page, order, current_order,
2156                         start_migratetype, fallback_mt);
2157 
2158                 return page;
2159         }
2160 
2161         return NULL;
2162 }
2163 
2164 /*
2165  * Do the hard work of removing an element from the buddy allocator.
2166  * Call me with the zone->lock already held.
2167  */
2168 static struct page *__rmqueue(struct zone *zone, unsigned int order,
2169                                 int migratetype)
2170 {
2171         struct page *page;
2172 
2173         page = __rmqueue_smallest(zone, order, migratetype);
2174         if (unlikely(!page)) {
2175                 if (migratetype == MIGRATE_MOVABLE)
2176                         page = __rmqueue_cma_fallback(zone, order);
2177 
2178                 if (!page)
2179                         page = __rmqueue_fallback(zone, order, migratetype);
2180         }
2181 
2182         trace_mm_page_alloc_zone_locked(page, order, migratetype);
2183         return page;
2184 }
2185 
2186 /*
2187  * Obtain a specified number of elements from the buddy allocator, all under
2188  * a single hold of the lock, for efficiency.  Add them to the supplied list.
2189  * Returns the number of new pages which were placed at *list.
2190  */
2191 static int rmqueue_bulk(struct zone *zone, unsigned int order,
2192                         unsigned long count, struct list_head *list,
2193                         int migratetype, bool cold)
2194 {
2195         int i;
2196 
2197         spin_lock(&zone->lock);
2198         for (i = 0; i < count; ++i) {
2199                 struct page *page = __rmqueue(zone, order, migratetype);
2200                 if (unlikely(page == NULL))
2201                         break;
2202 
2203                 if (unlikely(check_pcp_refill(page)))
2204                         continue;
2205 
2206                 /*
2207                  * Split buddy pages returned by expand() are received here
2208                  * in physical page order. The page is added to the callers and
2209                  * list and the list head then moves forward. From the callers
2210                  * perspective, the linked list is ordered by page number in
2211                  * some conditions. This is useful for IO devices that can
2212                  * merge IO requests if the physical pages are ordered
2213                  * properly.
2214                  */
2215                 if (likely(!cold))
2216                         list_add(&page->lru, list);
2217                 else
2218                         list_add_tail(&page->lru, list);
2219                 list = &page->lru;
2220                 if (is_migrate_cma(get_pcppage_migratetype(page)))
2221                         __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
2222                                               -(1 << order));
2223         }
2224         __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
2225         spin_unlock(&zone->lock);
2226         return i;
2227 }
2228 
2229 #ifdef CONFIG_NUMA
2230 /*
2231  * Called from the vmstat counter updater to drain pagesets of this
2232  * currently executing processor on remote nodes after they have
2233  * expired.
2234  *
2235  * Note that this function must be called with the thread pinned to
2236  * a single processor.
2237  */
2238 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
2239 {
2240         unsigned long flags;
2241         int to_drain, batch;
2242 
2243         local_irq_save(flags);
2244         batch = READ_ONCE(pcp->batch);
2245         to_drain = min(pcp->count, batch);
2246         if (to_drain > 0) {
2247                 free_pcppages_bulk(zone, to_drain, pcp);
2248                 pcp->count -= to_drain;
2249         }
2250         local_irq_restore(flags);
2251 }
2252 #endif
2253 
2254 /*
2255  * Drain pcplists of the indicated processor and zone.
2256  *
2257  * The processor must either be the current processor and the
2258  * thread pinned to the current processor or a processor that
2259  * is not online.
2260  */
2261 static void drain_pages_zone(unsigned int cpu, struct zone *zone)
2262 {
2263         unsigned long flags;
2264         struct per_cpu_pageset *pset;
2265         struct per_cpu_pages *pcp;
2266 
2267         local_irq_save(flags);
2268         pset = per_cpu_ptr(zone->pageset, cpu);
2269 
2270         pcp = &pset->pcp;
2271         if (pcp->count) {
2272                 free_pcppages_bulk(zone, pcp->count, pcp);
2273                 pcp->count = 0;
2274         }
2275         local_irq_restore(flags);
2276 }
2277 
2278 /*
2279  * Drain pcplists of all zones on the indicated processor.
2280  *
2281  * The processor must either be the current processor and the
2282  * thread pinned to the current processor or a processor that
2283  * is not online.
2284  */
2285 static void drain_pages(unsigned int cpu)
2286 {
2287         struct zone *zone;
2288 
2289         for_each_populated_zone(zone) {
2290                 drain_pages_zone(cpu, zone);
2291         }
2292 }
2293 
2294 /*
2295  * Spill all of this CPU's per-cpu pages back into the buddy allocator.
2296  *
2297  * The CPU has to be pinned. When zone parameter is non-NULL, spill just
2298  * the single zone's pages.
2299  */
2300 void drain_local_pages(struct zone *zone)
2301 {
2302         int cpu = smp_processor_id();
2303 
2304         if (zone)
2305                 drain_pages_zone(cpu, zone);
2306         else
2307                 drain_pages(cpu);
2308 }
2309 
2310 /*
2311  * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
2312  *
2313  * When zone parameter is non-NULL, spill just the single zone's pages.
2314  *
2315  * Note that this code is protected against sending an IPI to an offline
2316  * CPU but does not guarantee sending an IPI to newly hotplugged CPUs:
2317  * on_each_cpu_mask() blocks hotplug and won't talk to offlined CPUs but
2318  * nothing keeps CPUs from showing up after we populated the cpumask and
2319  * before the call to on_each_cpu_mask().
2320  */
2321 void drain_all_pages(struct zone *zone)
2322 {
2323         int cpu;
2324 
2325         /*
2326          * Allocate in the BSS so we wont require allocation in
2327          * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
2328          */
2329         static cpumask_t cpus_with_pcps;
2330 
2331         /*
2332          * We don't care about racing with CPU hotplug event
2333          * as offline notification will cause the notified
2334          * cpu to drain that CPU pcps and on_each_cpu_mask
2335          * disables preemption as part of its processing
2336          */
2337         for_each_online_cpu(cpu) {
2338                 struct per_cpu_pageset *pcp;
2339                 struct zone *z;
2340                 bool has_pcps = false;
2341 
2342                 if (zone) {
2343                         pcp = per_cpu_ptr(zone->pageset, cpu);
2344                         if (pcp->pcp.count)
2345                                 has_pcps = true;
2346                 } else {
2347                         for_each_populated_zone(z) {
2348                                 pcp = per_cpu_ptr(z->pageset, cpu);
2349                                 if (pcp->pcp.count) {
2350                                         has_pcps = true;
2351                                         break;
2352                                 }
2353                         }
2354                 }
2355 
2356                 if (has_pcps)
2357                         cpumask_set_cpu(cpu, &cpus_with_pcps);
2358                 else
2359                         cpumask_clear_cpu(cpu, &cpus_with_pcps);
2360         }
2361         on_each_cpu_mask(&cpus_with_pcps, (smp_call_func_t) drain_local_pages,
2362                                                                 zone, 1);
2363 }
2364 
2365 #ifdef CONFIG_HIBERNATION
2366 
2367 void mark_free_pages(struct zone *zone)
2368 {
2369         unsigned long pfn, max_zone_pfn;
2370         unsigned long flags;
2371         unsigned int order, t;
2372         struct page *page;
2373 
2374         if (zone_is_empty(zone))
2375                 return;
2376 
2377         spin_lock_irqsave(&zone->lock, flags);
2378 
2379         max_zone_pfn = zone_end_pfn(zone);
2380         for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
2381                 if (pfn_valid(pfn)) {
2382                         page = pfn_to_page(pfn);
2383 
2384                         if (page_zone(page) != zone)
2385                                 continue;
2386 
2387                         if (!swsusp_page_is_forbidden(page))
2388                                 swsusp_unset_page_free(page);
2389                 }
2390 
2391         for_each_migratetype_order(order, t) {
2392                 list_for_each_entry(page,
2393                                 &zone->free_area[order].free_list[t], lru) {
2394                         unsigned long i;
2395 
2396                         pfn = page_to_pfn(page);
2397                         for (i = 0; i < (1UL << order); i++)
2398                                 swsusp_set_page_free(pfn_to_page(pfn + i));
2399                 }
2400         }
2401         spin_unlock_irqrestore(&zone->lock, flags);
2402 }
2403 #endif /* CONFIG_PM */
2404 
2405 /*
2406  * Free a 0-order page
2407  * cold == true ? free a cold page : free a hot page
2408  */
2409 void free_hot_cold_page(struct page *page, bool cold)
2410 {
2411         struct zone *zone = page_zone(page);
2412         struct per_cpu_pages *pcp;
2413         unsigned long flags;
2414         unsigned long pfn = page_to_pfn(page);
2415         int migratetype;
2416 
2417         if (!free_pcp_prepare(page))
2418                 return;
2419 
2420         migratetype = get_pfnblock_migratetype(page, pfn);
2421         set_pcppage_migratetype(page, migratetype);
2422         local_irq_save(flags);
2423         __count_vm_event(PGFREE);
2424 
2425         /*
2426          * We only track unmovable, reclaimable and movable on pcp lists.
2427          * Free ISOLATE pages back to the allocator because they are being
2428          * offlined but treat RESERVE as movable pages so we can get those
2429          * areas back if necessary. Otherwise, we may have to free
2430          * excessively into the page allocator
2431          */
2432         if (migratetype >= MIGRATE_PCPTYPES) {
2433                 if (unlikely(is_migrate_isolate(migratetype))) {
2434                         free_one_page(zone, page, pfn, 0, migratetype);
2435                         goto out;
2436                 }
2437                 migratetype = MIGRATE_MOVABLE;
2438         }
2439 
2440         pcp = &this_cpu_ptr(zone->pageset)->pcp;
2441         if (!cold)
2442                 list_add(&page->lru, &pcp->lists[migratetype]);
2443         else
2444                 list_add_tail(&page->lru, &pcp->lists[migratetype]);
2445         pcp->count++;
2446         if (pcp->count >= pcp->high) {
2447                 unsigned long batch = READ_ONCE(pcp->batch);
2448                 free_pcppages_bulk(zone, batch, pcp);
2449                 pcp->count -= batch;
2450         }
2451 
2452 out:
2453         local_irq_restore(flags);
2454 }
2455 
2456 /*
2457  * Free a list of 0-order pages
2458  */
2459 void free_hot_cold_page_list(struct list_head *list, bool cold)
2460 {
2461         struct page *page, *next;
2462 
2463         list_for_each_entry_safe(page, next, list, lru) {
2464                 trace_mm_page_free_batched(page, cold);
2465                 free_hot_cold_page(page, cold);
2466         }
2467 }
2468 
2469 /*
2470  * split_page takes a non-compound higher-order page, and splits it into
2471  * n (1<<order) sub-pages: page[0..n]
2472  * Each sub-page must be freed individually.
2473  *
2474  * Note: this is probably too low level an operation for use in drivers.
2475  * Please consult with lkml before using this in your driver.
2476  */
2477 void split_page(struct page *page, unsigned int order)
2478 {
2479         int i;
2480 
2481         VM_BUG_ON_PAGE(PageCompound(page), page);
2482         VM_BUG_ON_PAGE(!page_count(page), page);
2483 
2484 #ifdef CONFIG_KMEMCHECK
2485         /*
2486          * Split shadow pages too, because free(page[0]) would
2487          * otherwise free the whole shadow.
2488          */
2489         if (kmemcheck_page_is_tracked(page))
2490                 split_page(virt_to_page(page[0].shadow), order);
2491 #endif
2492 
2493         for (i = 1; i < (1 << order); i++)
2494                 set_page_refcounted(page + i);
2495         split_page_owner(page, order);
2496 }
2497 EXPORT_SYMBOL_GPL(split_page);
2498 
2499 int __isolate_free_page(struct page *page, unsigned int order)
2500 {
2501         unsigned long watermark;
2502         struct zone *zone;
2503         int mt;
2504 
2505         BUG_ON(!PageBuddy(page));
2506 
2507         zone = page_zone(page);
2508         mt = get_pageblock_migratetype(page);
2509 
2510         if (!is_migrate_isolate(mt)) {
2511                 /*
2512                  * Obey watermarks as if the page was being allocated. We can
2513                  * emulate a high-order watermark check with a raised order-0
2514                  * watermark, because we already know our high-order page
2515                  * exists.
2516                  */
2517                 watermark = min_wmark_pages(zone) + (1UL << order);
2518                 if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
2519                         return 0;
2520 
2521                 __mod_zone_freepage_state(zone, -(1UL << order), mt);
2522         }
2523 
2524         /* Remove page from free list */
2525         list_del(&page->lru);
2526         zone->free_area[order].nr_free--;
2527         rmv_page_order(page);
2528 
2529         /*
2530          * Set the pageblock if the isolated page is at least half of a
2531          * pageblock
2532          */
2533         if (order >= pageblock_order - 1) {
2534                 struct page *endpage = page + (1 << order) - 1;
2535                 for (; page < endpage; page += pageblock_nr_pages) {
2536                         int mt = get_pageblock_migratetype(page);
2537                         if (!is_migrate_isolate(mt) && !is_migrate_cma(mt))
2538                                 set_pageblock_migratetype(page,
2539                                                           MIGRATE_MOVABLE);
2540                 }
2541         }
2542 
2543 
2544         return 1UL << order;
2545 }
2546 
2547 /*
2548  * Update NUMA hit/miss statistics
2549  *
2550  * Must be called with interrupts disabled.
2551  *
2552  * When __GFP_OTHER_NODE is set assume the node of the preferred
2553  * zone is the local node. This is useful for daemons who allocate
2554  * memory on behalf of other processes.
2555  */
2556 static inline void zone_statistics(struct zone *preferred_zone, struct zone *z,
2557                                                                 gfp_t flags)
2558 {
2559 #ifdef CONFIG_NUMA
2560         int local_nid = numa_node_id();
2561         enum zone_stat_item local_stat = NUMA_LOCAL;
2562 
2563         if (unlikely(flags & __GFP_OTHER_NODE)) {
2564                 local_stat = NUMA_OTHER;
2565                 local_nid = preferred_zone->node;
2566         }
2567 
2568         if (z->node == local_nid) {
2569                 __inc_zone_state(z, NUMA_HIT);
2570                 __inc_zone_state(z, local_stat);
2571         } else {
2572                 __inc_zone_state(z, NUMA_MISS);
2573                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
2574         }
2575 #endif
2576 }
2577 
2578 /*
2579  * Allocate a page from the given zone. Use pcplists for order-0 allocations.
2580  */
2581 static inline
2582 struct page *buffered_rmqueue(struct zone *preferred_zone,
2583                         struct zone *zone, unsigned int order,
2584                         gfp_t gfp_flags, unsigned int alloc_flags,
2585                         int migratetype)
2586 {
2587         unsigned long flags;
2588         struct page *page;
2589         bool cold = ((gfp_flags & __GFP_COLD) != 0);
2590 
2591         if (likely(order == 0)) {
2592                 struct per_cpu_pages *pcp;
2593                 struct list_head *list;
2594 
2595                 local_irq_save(flags);
2596                 do {
2597                         pcp = &this_cpu_ptr(zone->pageset)->pcp;
2598                         list = &pcp->lists[migratetype];
2599                         if (list_empty(list)) {
2600                                 pcp->count += rmqueue_bulk(zone, 0,
2601                                                 pcp->batch, list,
2602                                                 migratetype, cold);
2603                                 if (unlikely(list_empty(list)))
2604                                         goto failed;
2605                         }
2606 
2607                         if (cold)
2608                                 page = list_last_entry(list, struct page, lru);
2609                         else
2610                                 page = list_first_entry(list, struct page, lru);
2611 
2612                         list_del(&page->lru);
2613                         pcp->count--;
2614 
2615                 } while (check_new_pcp(page));
2616         } else {
2617                 /*
2618                  * We most definitely don't want callers attempting to
2619                  * allocate greater than order-1 page units with __GFP_NOFAIL.
2620                  */
2621                 WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
2622                 spin_lock_irqsave(&zone->lock, flags);
2623 
2624                 do {
2625                         page = NULL;
2626                         if (alloc_flags & ALLOC_HARDER) {
2627                                 page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
2628                                 if (page)
2629                                         trace_mm_page_alloc_zone_locked(page, order, migratetype);
2630                         }
2631                         if (!page)
2632                                 page = __rmqueue(zone, order, migratetype);
2633                 } while (page && check_new_pages(page, order));
2634                 spin_unlock(&zone->lock);
2635                 if (!page)
2636                         goto failed;
2637                 __mod_zone_freepage_state(zone, -(1 << order),
2638                                           get_pcppage_migratetype(page));
2639         }
2640 
2641         __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
2642         zone_statistics(preferred_zone, zone, gfp_flags);
2643         local_irq_restore(flags);
2644 
2645         VM_BUG_ON_PAGE(bad_range(zone, page), page);
2646         return page;
2647 
2648 failed:
2649         local_irq_restore(flags);
2650         return NULL;
2651 }
2652 
2653 #ifdef CONFIG_FAIL_PAGE_ALLOC
2654 
2655 static struct {
2656         struct fault_attr attr;
2657 
2658         bool ignore_gfp_highmem;
2659         bool ignore_gfp_reclaim;
2660         u32 min_order;
2661 } fail_page_alloc = {
2662         .attr = FAULT_ATTR_INITIALIZER,
2663         .ignore_gfp_reclaim = true,
2664         .ignore_gfp_highmem = true,
2665         .min_order = 1,
2666 };
2667 
2668 static int __init setup_fail_page_alloc(char *str)
2669 {
2670         return setup_fault_attr(&fail_page_alloc.attr, str);
2671 }
2672 __setup("fail_page_alloc=", setup_fail_page_alloc);
2673 
2674 static bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
2675 {
2676         if (order < fail_page_alloc.min_order)
2677                 return false;
2678         if (gfp_mask & __GFP_NOFAIL)
2679                 return false;
2680         if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
2681                 return false;
2682         if (fail_page_alloc.ignore_gfp_reclaim &&
2683                         (gfp_mask & __GFP_DIRECT_RECLAIM))
2684                 return false;
2685 
2686         return should_fail(&fail_page_alloc.attr, 1 << order);
2687 }
2688 
2689 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
2690 
2691 static int __init fail_page_alloc_debugfs(void)
2692 {
2693         umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
2694         struct dentry *dir;
2695 
2696         dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
2697                                         &fail_page_alloc.attr);
2698         if (IS_ERR(dir))
2699                 return PTR_ERR(dir);
2700 
2701         if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
2702                                 &fail_page_alloc.ignore_gfp_reclaim))
2703                 goto fail;
2704         if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir,
2705                                 &fail_page_alloc.ignore_gfp_highmem))
2706                 goto fail;
2707         if (!debugfs_create_u32("min-order", mode, dir,
2708                                 &fail_page_alloc.min_order))
2709                 goto fail;
2710 
2711         return 0;
2712 fail:
2713         debugfs_remove_recursive(dir);
2714 
2715         return -ENOMEM;
2716 }
2717 
2718 late_initcall(fail_page_alloc_debugfs);
2719 
2720 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
2721 
2722 #else /* CONFIG_FAIL_PAGE_ALLOC */
2723 
2724 static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
2725 {
2726         return false;
2727 }
2728 
2729 #endif /* CONFIG_FAIL_PAGE_ALLOC */
2730 
2731 /*
2732  * Return true if free base pages are above 'mark'. For high-order checks it
2733  * will return true of the order-0 watermark is reached and there is at least
2734  * one free page of a suitable size. Checking now avoids taking the zone lock
2735  * to check in the allocation paths if no pages are free.
2736  */
2737 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
2738                          int classzone_idx, unsigned int alloc_flags,
2739                          long free_pages)
2740 {
2741         long min = mark;
2742         int o;
2743         const bool alloc_harder = (alloc_flags & ALLOC_HARDER);
2744 
2745         /* free_pages may go negative - that's OK */
2746         free_pages -= (1 << order) - 1;
2747 
2748         if (alloc_flags & ALLOC_HIGH)
2749                 min -= min / 2;
2750 
2751         /*
2752          * If the caller does not have rights to ALLOC_HARDER then subtract
2753          * the high-atomic reserves. This will over-estimate the size of the
2754          * atomic reserve but it avoids a search.
2755          */
2756         if (likely(!alloc_harder))
2757                 free_pages -= z->nr_reserved_highatomic;
2758         else
2759                 min -= min / 4;
2760 
2761 #ifdef CONFIG_CMA
2762         /* If allocation can't use CMA areas don't use free CMA pages */
2763         if (!(alloc_flags & ALLOC_CMA))
2764                 free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
2765 #endif
2766 
2767         /*
2768          * Check watermarks for an order-0 allocation request. If these
2769          * are not met, then a high-order request also cannot go ahead
2770          * even if a suitable page happened to be free.
2771          */
2772         if (free_pages <= min + z->lowmem_reserve[classzone_idx])
2773                 return false;
2774 
2775         /* If this is an order-0 request then the watermark is fine */
2776         if (!order)
2777                 return true;
2778 
2779         /* For a high-order request, check at least one suitable page is free */
2780         for (o = order; o < MAX_ORDER; o++) {
2781                 struct free_area *area = &z->free_area[o];
2782                 int mt;
2783 
2784                 if (!area->nr_free)
2785                         continue;
2786 
2787                 if (alloc_harder)
2788                         return true;
2789 
2790                 for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
2791                         if (!list_empty(&area->free_list[mt]))
2792                                 return true;
2793                 }
2794 
2795 #ifdef CONFIG_CMA
2796                 if ((alloc_flags & ALLOC_CMA) &&
2797                     !list_empty(&area->free_list[MIGRATE_CMA])) {
2798                         return true;
2799                 }
2800 #endif
2801         }
2802         return false;
2803 }
2804 
2805 bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
2806                       int classzone_idx, unsigned int alloc_flags)
2807 {
2808         return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
2809                                         zone_page_state(z, NR_FREE_PAGES));
2810 }
2811 
2812 static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
2813                 unsigned long mark, int classzone_idx, unsigned int alloc_flags)
2814 {
2815         long free_pages = zone_page_state(z, NR_FREE_PAGES);
2816         long cma_pages = 0;
2817 
2818 #ifdef CONFIG_CMA
2819         /* If allocation can't use CMA areas don't use free CMA pages */
2820         if (!(alloc_flags & ALLOC_CMA))
2821                 cma_pages = zone_page_state(z, NR_FREE_CMA_PAGES);
2822 #endif
2823 
2824         /*
2825          * Fast check for order-0 only. If this fails then the reserves
2826          * need to be calculated. There is a corner case where the check
2827          * passes but only the high-order atomic reserve are free. If
2828          * the caller is !atomic then it'll uselessly search the free
2829          * list. That corner case is then slower but it is harmless.
2830          */
2831         if (!order && (free_pages - cma_pages) > mark + z->lowmem_reserve[classzone_idx])
2832                 return true;
2833 
2834         return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
2835                                         free_pages);
2836 }
2837 
2838 bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
2839                         unsigned long mark, int classzone_idx)
2840 {
2841         long free_pages = zone_page_state(z, NR_FREE_PAGES);
2842 
2843         if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
2844                 free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
2845 
2846         return __zone_watermark_ok(z, order, mark, classzone_idx, 0,
2847                                                                 free_pages);
2848 }
2849 
2850 #ifdef CONFIG_NUMA
2851 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
2852 {
2853         return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <
2854                                 RECLAIM_DISTANCE;
2855 }
2856 #else   /* CONFIG_NUMA */
2857 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
2858 {
2859         return true;
2860 }
2861 #endif  /* CONFIG_NUMA */
2862 
2863 /*
2864  * get_page_from_freelist goes through the zonelist trying to allocate
2865  * a page.
2866  */
2867 static struct page *
2868 get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
2869                                                 const struct alloc_context *ac)
2870 {
2871         struct zoneref *z = ac->preferred_zoneref;
2872         struct zone *zone;
2873         struct pglist_data *last_pgdat_dirty_limit = NULL;
2874 
2875         /*
2876          * Scan zonelist, looking for a zone with enough free.
2877          * See also __cpuset_node_allowed() comment in kernel/cpuset.c.
2878          */
2879         for_next_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
2880                                                                 ac->nodemask) {
2881                 struct page *page;
2882                 unsigned long mark;
2883 
2884                 if (cpusets_enabled() &&
2885                         (alloc_flags & ALLOC_CPUSET) &&
2886                         !__cpuset_zone_allowed(zone, gfp_mask))
2887                                 continue;
2888                 /*
2889                  * When allocating a page cache page for writing, we
2890                  * want to get it from a node that is within its dirty
2891                  * limit, such that no single node holds more than its
2892                  * proportional share of globally allowed dirty pages.
2893                  * The dirty limits take into account the node's
2894                  * lowmem reserves and high watermark so that kswapd
2895                  * should be able to balance it without having to
2896                  * write pages from its LRU list.
2897                  *
2898                  * XXX: For now, allow allocations to potentially
2899                  * exceed the per-node dirty limit in the slowpath
2900                  * (spread_dirty_pages unset) before going into reclaim,
2901                  * which is important when on a NUMA setup the allowed
2902                  * nodes are together not big enough to reach the
2903                  * global limit.  The proper fix for these situations
2904                  * will require awareness of nodes in the
2905                  * dirty-throttling and the flusher threads.
2906                  */
2907                 if (ac->spread_dirty_pages) {
2908                         if (last_pgdat_dirty_limit == zone->zone_pgdat)
2909                                 continue;
2910 
2911                         if (!node_dirty_ok(zone->zone_pgdat)) {
2912                                 last_pgdat_dirty_limit = zone->zone_pgdat;
2913                                 continue;
2914                         }
2915                 }
2916 
2917                 mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
2918                 if (!zone_watermark_fast(zone, order, mark,
2919                                        ac_classzone_idx(ac), alloc_flags)) {
2920                         int ret;
2921 
2922                         /* Checked here to keep the fast path fast */
2923                         BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
2924                         if (alloc_flags & ALLOC_NO_WATERMARKS)
2925                                 goto try_this_zone;
2926 
2927                         if (node_reclaim_mode == 0 ||
2928                             !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
2929                                 continue;
2930 
2931                         ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
2932                         switch (ret) {
2933                         case NODE_RECLAIM_NOSCAN:
2934                                 /* did not scan */
2935                                 continue;
2936                         case NODE_RECLAIM_FULL:
2937                                 /* scanned but unreclaimable */
2938                                 continue;
2939                         default:
2940                                 /* did we reclaim enough */
2941                                 if (zone_watermark_ok(zone, order, mark,
2942                                                 ac_classzone_idx(ac), alloc_flags))
2943                                         goto try_this_zone;
2944 
2945                                 continue;
2946                         }
2947                 }
2948 
2949 try_this_zone:
2950                 page = buffered_rmqueue(ac->preferred_zoneref->zone, zone, order,
2951                                 gfp_mask, alloc_flags, ac->migratetype);
2952                 if (page) {
2953                         prep_new_page(page, order, gfp_mask, alloc_flags);
2954 
2955                         /*
2956                          * If this is a high-order atomic allocation then check
2957                          * if the pageblock should be reserved for the future
2958                          */
2959                         if (unlikely(order && (alloc_flags & ALLOC_HARDER)))
2960                                 reserve_highatomic_pageblock(page, zone, order);
2961 
2962                         return page;
2963                 }
2964         }
2965 
2966         return NULL;
2967 }
2968 
2969 /*
2970  * Large machines with many possible nodes should not always dump per-node
2971  * meminfo in irq context.
2972  */
2973 static inline bool should_suppress_show_mem(void)
2974 {
2975         bool ret = false;
2976 
2977 #if NODES_SHIFT > 8
2978         ret = in_interrupt();
2979 #endif
2980         return ret;
2981 }
2982 
2983 static DEFINE_RATELIMIT_STATE(nopage_rs,
2984                 DEFAULT_RATELIMIT_INTERVAL,
2985                 DEFAULT_RATELIMIT_BURST);
2986 
2987 void warn_alloc(gfp_t gfp_mask, const char *fmt, ...)
2988 {
2989         unsigned int filter = SHOW_MEM_FILTER_NODES;
2990         struct va_format vaf;
2991         va_list args;
2992 
2993         if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) ||
2994             debug_guardpage_minorder() > 0)
2995                 return;
2996 
2997         /*
2998          * This documents exceptions given to allocations in certain
2999          * contexts that are allowed to allocate outside current's set
3000          * of allowed nodes.
3001          */
3002         if (!(gfp_mask & __GFP_NOMEMALLOC))
3003                 if (test_thread_flag(TIF_MEMDIE) ||
3004                     (current->flags & (PF_MEMALLOC | PF_EXITING)))
3005                         filter &= ~SHOW_MEM_FILTER_NODES;
3006         if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
3007                 filter &= ~SHOW_MEM_FILTER_NODES;
3008 
3009         pr_warn("%s: ", current->comm);
3010 
3011         va_start(args, fmt);
3012         vaf.fmt = fmt;
3013         vaf.va = &args;
3014         pr_cont("%pV", &vaf);
3015         va_end(args);
3016 
3017         pr_cont(", mode:%#x(%pGg)\n", gfp_mask, &gfp_mask);
3018 
3019         dump_stack();
3020         if (!should_suppress_show_mem())
3021                 show_mem(filter);
3022 }
3023 
3024 static inline struct page *
3025 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
3026         const struct alloc_context *ac, unsigned long *did_some_progress)
3027 {
3028         struct oom_control oc = {
3029                 .zonelist = ac->zonelist,
3030                 .nodemask = ac->nodemask,
3031                 .memcg = NULL,
3032                 .gfp_mask = gfp_mask,
3033                 .order = order,
3034         };
3035         struct page *page;
3036 
3037         *did_some_progress = 0;
3038 
3039         /*
3040          * Acquire the oom lock.  If that fails, somebody else is
3041          * making progress for us.
3042          */
3043         if (!mutex_trylock(&oom_lock)) {
3044                 *did_some_progress = 1;
3045                 schedule_timeout_uninterruptible(1);
3046                 return NULL;
3047         }
3048 
3049         /*
3050          * Go through the zonelist yet one more time, keep very high watermark
3051          * here, this is only to catch a parallel oom killing, we must fail if
3052          * we're still under heavy pressure.
3053          */
3054         page = get_page_from_freelist(gfp_mask | __GFP_HARDWALL, order,
3055                                         ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
3056         if (page)
3057                 goto out;
3058 
3059         if (!(gfp_mask & __GFP_NOFAIL)) {
3060                 /* Coredumps can quickly deplete all memory reserves */
3061                 if (current->flags & PF_DUMPCORE)
3062                         goto out;
3063                 /* The OOM killer will not help higher order allocs */
3064                 if (order > PAGE_ALLOC_COSTLY_ORDER)
3065                         goto out;
3066                 /* The OOM killer does not needlessly kill tasks for lowmem */
3067                 if (ac->high_zoneidx < ZONE_NORMAL)
3068                         goto out;
3069                 if (pm_suspended_storage())
3070                         goto out;
3071                 /*
3072                  * XXX: GFP_NOFS allocations should rather fail than rely on
3073                  * other request to make a forward progress.
3074                  * We are in an unfortunate situation where out_of_memory cannot
3075                  * do much for this context but let's try it to at least get
3076                  * access to memory reserved if the current task is killed (see
3077                  * out_of_memory). Once filesystems are ready to handle allocation
3078                  * failures more gracefully we should just bail out here.
3079                  */
3080 
3081                 /* The OOM killer may not free memory on a specific node */
3082                 if (gfp_mask & __GFP_THISNODE)
3083                         goto out;
3084         }
3085         /* Exhausted what can be done so it's blamo time */
3086         if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
3087                 *did_some_progress = 1;
3088 
3089                 if (gfp_mask & __GFP_NOFAIL) {
3090                         page = get_page_from_freelist(gfp_mask, order,
3091                                         ALLOC_NO_WATERMARKS|ALLOC_CPUSET, ac);
3092                         /*
3093                          * fallback to ignore cpuset restriction if our nodes
3094                          * are depleted
3095                          */
3096                         if (!page)
3097                                 page = get_page_from_freelist(gfp_mask, order,
3098                                         ALLOC_NO_WATERMARKS, ac);
3099                 }
3100         }
3101 out:
3102         mutex_unlock(&oom_lock);
3103         return page;
3104 }
3105 
3106 /*
3107  * Maximum number of compaction retries wit a progress before OOM
3108  * killer is consider as the only way to move forward.
3109  */
3110 #define MAX_COMPACT_RETRIES 16
3111 
3112 #ifdef CONFIG_COMPACTION
3113 /* Try memory compaction for high-order allocations before reclaim */
3114 static struct page *
3115 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
3116                 unsigned int alloc_flags, const struct alloc_context *ac,
3117                 enum compact_priority prio, enum compact_result *compact_result)
3118 {
3119         struct page *page;
3120 
3121         if (!order)
3122                 return NULL;
3123 
3124         current->flags |= PF_MEMALLOC;
3125         *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
3126                                                                         prio);
3127         current->flags &= ~PF_MEMALLOC;
3128 
3129         if (*compact_result <= COMPACT_INACTIVE)
3130                 return NULL;
3131 
3132         /*
3133          * At least in one zone compaction wasn't deferred or skipped, so let's
3134          * count a compaction stall
3135          */
3136         count_vm_event(COMPACTSTALL);
3137 
3138         page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3139 
3140         if (page) {
3141                 struct zone *zone = page_zone(page);
3142 
3143                 zone->compact_blockskip_flush = false;
3144                 compaction_defer_reset(zone, order, true);
3145                 count_vm_event(COMPACTSUCCESS);
3146                 return page;
3147         }
3148 
3149         /*
3150          * It's bad if compaction run occurs and fails. The most likely reason
3151          * is that pages exist, but not enough to satisfy watermarks.
3152          */
3153         count_vm_event(COMPACTFAIL);
3154 
3155         cond_resched();
3156 
3157         return NULL;
3158 }
3159 
3160 static inline bool
3161 should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
3162                      enum compact_result compact_result,
3163                      enum compact_priority *compact_priority,
3164                      int *compaction_retries)
3165 {
3166         int max_retries = MAX_COMPACT_RETRIES;
3167         int min_priority;
3168 
3169         if (!order)
3170                 return false;
3171 
3172         if (compaction_made_progress(compact_result))
3173                 (*compaction_retries)++;
3174 
3175         /*
3176          * compaction considers all the zone as desperately out of memory
3177          * so it doesn't really make much sense to retry except when the
3178          * failure could be caused by insufficient priority
3179          */
3180         if (compaction_failed(compact_result))
3181                 goto check_priority;
3182 
3183         /*
3184          * make sure the compaction wasn't deferred or didn't bail out early
3185          * due to locks contention before we declare that we should give up.
3186          * But do not retry if the given zonelist is not suitable for
3187          * compaction.
3188          */
3189         if (compaction_withdrawn(compact_result))
3190                 return compaction_zonelist_suitable(ac, order, alloc_flags);
3191 
3192         /*
3193          * !costly requests are much more important than __GFP_REPEAT
3194          * costly ones because they are de facto nofail and invoke OOM
3195          * killer to move on while costly can fail and users are ready
3196          * to cope with that. 1/4 retries is rather arbitrary but we
3197          * would need much more detailed feedback from compaction to
3198          * make a better decision.
3199          */
3200         if (order > PAGE_ALLOC_COSTLY_ORDER)
3201                 max_retries /= 4;
3202         if (*compaction_retries <= max_retries)
3203                 return true;
3204 
3205         /*
3206          * Make sure there are attempts at the highest priority if we exhausted
3207          * all retries or failed at the lower priorities.
3208          */
3209 check_priority:
3210         min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ?
3211                         MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;
3212         if (*compact_priority > min_priority) {
3213                 (*compact_priority)--;
3214                 *compaction_retries = 0;
3215                 return true;
3216         }
3217         return false;
3218 }
3219 #else
3220 static inline struct page *
3221 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
3222                 unsigned int alloc_flags, const struct alloc_context *ac,
3223                 enum compact_priority prio, enum compact_result *compact_result)
3224 {
3225         *compact_result = COMPACT_SKIPPED;
3226         return NULL;
3227 }
3228 
3229 static inline bool
3230 should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
3231                      enum compact_result compact_result,
3232                      enum compact_priority *compact_priority,
3233                      int *compaction_retries)
3234 {
3235         struct zone *zone;
3236         struct zoneref *z;
3237 
3238         if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
3239                 return false;
3240 
3241         /*
3242          * There are setups with compaction disabled which would prefer to loop
3243          * inside the allocator rather than hit the oom killer prematurely.
3244          * Let's give them a good hope and keep retrying while the order-0
3245          * watermarks are OK.
3246          */
3247         for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
3248                                         ac->nodemask) {
3249                 if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
3250                                         ac_classzone_idx(ac), alloc_flags))
3251                         return true;
3252         }
3253         return false;
3254 }
3255 #endif /* CONFIG_COMPACTION */
3256 
3257 /* Perform direct synchronous page reclaim */
3258 static int
3259 __perform_reclaim(gfp_t gfp_mask, unsigned int order,
3260                                         const struct alloc_context *ac)
3261 {
3262         struct reclaim_state reclaim_state;
3263         int progress;
3264 
3265         cond_resched();
3266 
3267         /* We now go into synchronous reclaim */
3268         cpuset_memory_pressure_bump();
3269         current->flags |= PF_MEMALLOC;
3270         lockdep_set_current_reclaim_state(gfp_mask);
3271         reclaim_state.reclaimed_slab = 0;
3272         current->reclaim_state = &reclaim_state;
3273 
3274         progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
3275                                                                 ac->nodemask);
3276 
3277         current->reclaim_state = NULL;
3278         lockdep_clear_current_reclaim_state();
3279         current->flags &= ~PF_MEMALLOC;
3280 
3281         cond_resched();
3282 
3283         return progress;
3284 }
3285 
3286 /* The really slow allocator path where we enter direct reclaim */
3287 static inline struct page *
3288 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
3289                 unsigned int alloc_flags, const struct alloc_context *ac,
3290                 unsigned long *did_some_progress)
3291 {
3292         struct page *page = NULL;
3293         bool drained = false;
3294 
3295         *did_some_progress = __perform_reclaim(gfp_mask, order, ac);
3296         if (unlikely(!(*did_some_progress)))
3297                 return NULL;
3298 
3299 retry:
3300         page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3301 
3302         /*
3303          * If an allocation failed after direct reclaim, it could be because
3304          * pages are pinned on the per-cpu lists or in high alloc reserves.
3305          * Shrink them them and try again
3306          */
3307         if (!page && !drained) {
3308                 unreserve_highatomic_pageblock(ac);
3309                 drain_all_pages(NULL);
3310                 drained = true;
3311                 goto retry;
3312         }
3313 
3314         return page;
3315 }
3316 
3317 static void wake_all_kswapds(unsigned int order, const struct alloc_context *ac)
3318 {
3319         struct zoneref *z;
3320         struct zone *zone;
3321         pg_data_t *last_pgdat = NULL;
3322 
3323         for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
3324                                         ac->high_zoneidx, ac->nodemask) {
3325                 if (last_pgdat != zone->zone_pgdat)
3326                         wakeup_kswapd(zone, order, ac->high_zoneidx);
3327                 last_pgdat = zone->zone_pgdat;
3328         }
3329 }
3330 
3331 static inline unsigned int
3332 gfp_to_alloc_flags(gfp_t gfp_mask)
3333 {
3334         unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
3335 
3336         /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
3337         BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
3338 
3339         /*
3340          * The caller may dip into page reserves a bit more if the caller
3341          * cannot run direct reclaim, or if the caller has realtime scheduling
3342          * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
3343          * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
3344          */
3345         alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
3346 
3347         if (gfp_mask & __GFP_ATOMIC) {
3348                 /*
3349                  * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
3350                  * if it can't schedule.
3351                  */
3352                 if (!(gfp_mask & __GFP_NOMEMALLOC))
3353                         alloc_flags |= ALLOC_HARDER;
3354                 /*
3355                  * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
3356                  * comment for __cpuset_node_allowed().
3357                  */
3358                 alloc_flags &= ~ALLOC_CPUSET;
3359         } else if (unlikely(rt_task(current)) && !in_interrupt())
3360                 alloc_flags |= ALLOC_HARDER;
3361 
3362 #ifdef CONFIG_CMA
3363         if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
3364                 alloc_flags |= ALLOC_CMA;
3365 #endif
3366         return alloc_flags;
3367 }
3368 
3369 bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
3370 {
3371         if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
3372                 return false;
3373 
3374         if (gfp_mask & __GFP_MEMALLOC)
3375                 return true;
3376         if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
3377                 return true;
3378         if (!in_interrupt() &&
3379                         ((current->flags & PF_MEMALLOC) ||
3380                          unlikely(test_thread_flag(TIF_MEMDIE))))
3381                 return true;
3382 
3383         return false;
3384 }
3385 
3386 /*
3387  * Maximum number of reclaim retries without any progress before OOM killer
3388  * is consider as the only way to move forward.
3389  */
3390 #define MAX_RECLAIM_RETRIES 16
3391 
3392 /*
3393  * Checks whether it makes sense to retry the reclaim to make a forward progress
3394  * for the given allocation request.
3395  * The reclaim feedback represented by did_some_progress (any progress during
3396  * the last reclaim round) and no_progress_loops (number of reclaim rounds without
3397  * any progress in a row) is considered as well as the reclaimable pages on the
3398  * applicable zone list (with a backoff mechanism which is a function of
3399  * no_progress_loops).
3400  *
3401  * Returns true if a retry is viable or false to enter the oom path.
3402  */
3403 static inline bool
3404 should_reclaim_retry(gfp_t gfp_mask, unsigned order,
3405                      struct alloc_context *ac, int alloc_flags,
3406                      bool did_some_progress, int *no_progress_loops)
3407 {
3408         struct zone *zone;
3409         struct zoneref *z;
3410 
3411         /*
3412          * Costly allocations might have made a progress but this doesn't mean
3413          * their order will become available due to high fragmentation so
3414          * always increment the no progress counter for them
3415          */
3416         if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
3417                 *no_progress_loops = 0;
3418         else
3419                 (*no_progress_loops)++;
3420 
3421         /*
3422          * Make sure we converge to OOM if we cannot make any progress
3423          * several times in the row.
3424          */
3425         if (*no_progress_loops > MAX_RECLAIM_RETRIES)
3426                 return false;
3427 
3428         /*
3429          * Keep reclaiming pages while there is a chance this will lead
3430          * somewhere.  If none of the target zones can satisfy our allocation
3431          * request even if all reclaimable pages are considered then we are
3432          * screwed and have to go OOM.
3433          */
3434         for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
3435                                         ac->nodemask) {
3436                 unsigned long available;
3437                 unsigned long reclaimable;
3438 
3439                 available = reclaimable = zone_reclaimable_pages(zone);
3440                 available -= DIV_ROUND_UP((*no_progress_loops) * available,
3441                                           MAX_RECLAIM_RETRIES);
3442                 available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
3443 
3444                 /*
3445                  * Would the allocation succeed if we reclaimed the whole
3446                  * available?
3447                  */
3448                 if (__zone_watermark_ok(zone, order, min_wmark_pages(zone),
3449                                 ac_classzone_idx(ac), alloc_flags, available)) {
3450                         /*
3451                          * If we didn't make any progress and have a lot of
3452                          * dirty + writeback pages then we should wait for
3453                          * an IO to complete to slow down the reclaim and
3454                          * prevent from pre mature OOM
3455                          */
3456                         if (!did_some_progress) {
3457                                 unsigned long write_pending;
3458 
3459                                 write_pending = zone_page_state_snapshot(zone,
3460                                                         NR_ZONE_WRITE_PENDING);
3461 
3462                                 if (2 * write_pending > reclaimable) {
3463                                         congestion_wait(BLK_RW_ASYNC, HZ/10);
3464                                         return true;
3465                                 }
3466                         }
3467 
3468                         /*
3469                          * Memory allocation/reclaim might be called from a WQ
3470                          * context and the current implementation of the WQ
3471                          * concurrency control doesn't recognize that
3472                          * a particular WQ is congested if the worker thread is
3473                          * looping without ever sleeping. Therefore we have to
3474                          * do a short sleep here rather than calling
3475                          * cond_resched().
3476                          */
3477                         if (current->flags & PF_WQ_WORKER)
3478                                 schedule_timeout_uninterruptible(1);
3479                         else
3480                                 cond_resched();
3481 
3482                         return true;
3483                 }
3484         }
3485 
3486         return false;
3487 }
3488 
3489 static inline struct page *
3490 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
3491                                                 struct alloc_context *ac)
3492 {
3493         bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
3494         struct page *page = NULL;
3495         unsigned int alloc_flags;
3496         unsigned long did_some_progress;
3497         enum compact_priority compact_priority = DEF_COMPACT_PRIORITY;
3498         enum compact_result compact_result;
3499         int compaction_retries = 0;
3500         int no_progress_loops = 0;
3501         unsigned long alloc_start = jiffies;
3502         unsigned int stall_timeout = 10 * HZ;
3503 
3504         /*
3505          * In the slowpath, we sanity check order to avoid ever trying to
3506          * reclaim >= MAX_ORDER areas which will never succeed. Callers may
3507          * be using allocators in order of preference for an area that is
3508          * too large.
3509          */
3510         if (order >= MAX_ORDER) {
3511                 WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
3512                 return NULL;
3513         }
3514 
3515         /*
3516          * We also sanity check to catch abuse of atomic reserves being used by
3517          * callers that are not in atomic context.
3518          */
3519         if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) ==
3520                                 (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
3521                 gfp_mask &= ~__GFP_ATOMIC;
3522 
3523         /*
3524          * The fast path uses conservative alloc_flags to succeed only until
3525          * kswapd needs to be woken up, and to avoid the cost of setting up
3526          * alloc_flags precisely. So we do that now.
3527          */
3528         alloc_flags = gfp_to_alloc_flags(gfp_mask);
3529 
3530         if (gfp_mask & __GFP_KSWAPD_RECLAIM)
3531                 wake_all_kswapds(order, ac);
3532 
3533         /*
3534          * The adjusted alloc_flags might result in immediate success, so try
3535          * that first
3536          */
3537         page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3538         if (page)
3539                 goto got_pg;
3540 
3541         /*
3542          * For costly allocations, try direct compaction first, as it's likely
3543          * that we have enough base pages and don't need to reclaim. Don't try
3544          * that for allocations that are allowed to ignore watermarks, as the
3545          * ALLOC_NO_WATERMARKS attempt didn't yet happen.
3546          */
3547         if (can_direct_reclaim && order > PAGE_ALLOC_COSTLY_ORDER &&
3548                 !gfp_pfmemalloc_allowed(gfp_mask)) {
3549                 page = __alloc_pages_direct_compact(gfp_mask, order,
3550                                                 alloc_flags, ac,
3551                                                 INIT_COMPACT_PRIORITY,
3552                                                 &compact_result);
3553                 if (page)
3554                         goto got_pg;
3555 
3556                 /*
3557                  * Checks for costly allocations with __GFP_NORETRY, which
3558                  * includes THP page fault allocations
3559                  */
3560                 if (gfp_mask & __GFP_NORETRY) {
3561                         /*
3562                          * If compaction is deferred for high-order allocations,
3563                          * it is because sync compaction recently failed. If
3564                          * this is the case and the caller requested a THP
3565                          * allocation, we do not want to heavily disrupt the
3566                          * system, so we fail the allocation instead of entering
3567                          * direct reclaim.
3568                          */
3569                         if (compact_result == COMPACT_DEFERRED)
3570                                 goto nopage;
3571 
3572                         /*
3573                          * Looks like reclaim/compaction is worth trying, but
3574                          * sync compaction could be very expensive, so keep
3575                          * using async compaction.
3576                          */
3577                         compact_priority = INIT_COMPACT_PRIORITY;
3578                 }
3579         }
3580 
3581 retry:
3582         /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
3583         if (gfp_mask & __GFP_KSWAPD_RECLAIM)
3584                 wake_all_kswapds(order, ac);
3585 
3586         if (gfp_pfmemalloc_allowed(gfp_mask))
3587                 alloc_flags = ALLOC_NO_WATERMARKS;
3588 
3589         /*
3590          * Reset the zonelist iterators if memory policies can be ignored.
3591          * These allocations are high priority and system rather than user
3592          * orientated.
3593          */
3594         if (!(alloc_flags & ALLOC_CPUSET) || (alloc_flags & ALLOC_NO_WATERMARKS)) {
3595                 ac->zonelist = node_zonelist(numa_node_id(), gfp_mask);
3596                 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
3597                                         ac->high_zoneidx, ac->nodemask);
3598         }
3599 
3600         /* Attempt with potentially adjusted zonelist and alloc_flags */
3601         page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3602         if (page)
3603                 goto got_pg;
3604 
3605         /* Caller is not willing to reclaim, we can't balance anything */
3606         if (!can_direct_reclaim) {
3607                 /*
3608                  * All existing users of the __GFP_NOFAIL are blockable, so warn
3609                  * of any new users that actually allow this type of allocation
3610                  * to fail.
3611                  */
3612                 WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL);
3613                 goto nopage;
3614         }
3615 
3616         /* Avoid recursion of direct reclaim */
3617         if (current->flags & PF_MEMALLOC) {
3618                 /*
3619                  * __GFP_NOFAIL request from this context is rather bizarre
3620                  * because we cannot reclaim anything and only can loop waiting
3621                  * for somebody to do a work for us.
3622                  */
3623                 if (WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
3624                         cond_resched();
3625                         goto retry;
3626                 }
3627                 goto nopage;
3628         }
3629 
3630         /* Avoid allocations with no watermarks from looping endlessly */
3631         if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
3632                 goto nopage;
3633 
3634 
3635         /* Try direct reclaim and then allocating */
3636         page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
3637                                                         &did_some_progress);
3638         if (page)
3639                 goto got_pg;
3640 
3641         /* Try direct compaction and then allocating */
3642         page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
3643                                         compact_priority, &compact_result);
3644         if (page)
3645                 goto got_pg;
3646 
3647         /* Do not loop if specifically requested */
3648         if (gfp_mask & __GFP_NORETRY)
3649                 goto nopage;
3650 
3651         /*
3652          * Do not retry costly high order allocations unless they are
3653          * __GFP_REPEAT
3654          */
3655         if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_REPEAT))
3656                 goto nopage;
3657 
3658         /* Make sure we know about allocations which stall for too long */
3659         if (time_after(jiffies, alloc_start + stall_timeout)) {
3660                 warn_alloc(gfp_mask,
3661                         "page allocation stalls for %ums, order:%u",
3662                         jiffies_to_msecs(jiffies-alloc_start), order);
3663                 stall_timeout += 10 * HZ;
3664         }
3665 
3666         if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
3667                                  did_some_progress > 0, &no_progress_loops))
3668                 goto retry;
3669 
3670         /*
3671          * It doesn't make any sense to retry for the compaction if the order-0
3672          * reclaim is not able to make any progress because the current
3673          * implementation of the compaction depends on the sufficient amount
3674          * of free memory (see __compaction_suitable)
3675          */
3676         if (did_some_progress > 0 &&
3677                         should_compact_retry(ac, order, alloc_flags,
3678                                 compact_result, &compact_priority,
3679                                 &compaction_retries))
3680                 goto retry;
3681 
3682         /* Reclaim has failed us, start killing things */
3683         page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
3684         if (page)
3685                 goto got_pg;
3686 
3687         /* Retry as long as the OOM killer is making progress */
3688         if (did_some_progress) {
3689                 no_progress_loops = 0;
3690                 goto retry;
3691         }
3692 
3693 nopage:
3694         warn_alloc(gfp_mask,
3695                         "page allocation failure: order:%u", order);
3696 got_pg:
3697         return page;
3698 }
3699 
3700 /*
3701  * This is the 'heart' of the zoned buddy allocator.
3702  */
3703 struct page *
3704 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
3705                         struct zonelist *zonelist, nodemask_t *nodemask)
3706 {
3707         struct page *page;
3708         unsigned int cpuset_mems_cookie;
3709         unsigned int alloc_flags = ALLOC_WMARK_LOW;
3710         gfp_t alloc_mask = gfp_mask; /* The gfp_t that was actually used for allocation */
3711         struct alloc_context ac = {
3712                 .high_zoneidx = gfp_zone(gfp_mask),
3713                 .zonelist = zonelist,
3714                 .nodemask = nodemask,
3715                 .migratetype = gfpflags_to_migratetype(gfp_mask),
3716         };
3717 
3718         if (cpusets_enabled()) {
3719                 alloc_mask |= __GFP_HARDWALL;
3720                 alloc_flags |= ALLOC_CPUSET;
3721                 if (!ac.nodemask)
3722                         ac.nodemask = &cpuset_current_mems_allowed;
3723         }
3724 
3725         gfp_mask &= gfp_allowed_mask;
3726 
3727         lockdep_trace_alloc(gfp_mask);
3728 
3729         might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
3730 
3731         if (should_fail_alloc_page(gfp_mask, order))
3732                 return NULL;
3733 
3734         /*
3735          * Check the zones suitable for the gfp_mask contain at least one
3736          * valid zone. It's possible to have an empty zonelist as a result
3737          * of __GFP_THISNODE and a memoryless node
3738          */
3739         if (unlikely(!zonelist->_zonerefs->zone))
3740                 return NULL;
3741 
3742         if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE)
3743                 alloc_flags |= ALLOC_CMA;
3744 
3745 retry_cpuset:
3746         cpuset_mems_cookie = read_mems_allowed_begin();
3747 
3748         /* Dirty zone balancing only done in the fast path */
3749         ac.spread_dirty_pages = (gfp_mask & __GFP_WRITE);
3750 
3751         /*
3752          * The preferred zone is used for statistics but crucially it is
3753          * also used as the starting point for the zonelist iterator. It
3754          * may get reset for allocations that ignore memory policies.
3755          */
3756         ac.preferred_zoneref = first_zones_zonelist(ac.zonelist,
3757                                         ac.high_zoneidx, ac.nodemask);
3758         if (!ac.preferred_zoneref) {
3759                 page = NULL;
3760                 goto no_zone;
3761         }
3762 
3763         /* First allocation attempt */
3764         page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
3765         if (likely(page))
3766                 goto out;
3767 
3768         /*
3769          * Runtime PM, block IO and its error handling path can deadlock
3770          * because I/O on the device might not complete.
3771          */
3772         alloc_mask = memalloc_noio_flags(gfp_mask);
3773         ac.spread_dirty_pages = false;
3774 
3775         /*
3776          * Restore the original nodemask if it was potentially replaced with
3777          * &cpuset_current_mems_allowed to optimize the fast-path attempt.
3778          */
3779         if (cpusets_enabled())
3780                 ac.nodemask = nodemask;
3781         page = __alloc_pages_slowpath(alloc_mask, order, &ac);
3782 
3783 no_zone:
3784         /*
3785          * When updating a task's mems_allowed, it is possible to race with
3786          * parallel threads in such a way that an allocation can fail while
3787          * the mask is being updated. If a page allocation is about to fail,
3788          * check if the cpuset changed during allocation and if so, retry.
3789          */
3790         if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie))) {
3791                 alloc_mask = gfp_mask;
3792                 goto retry_cpuset;
3793         }
3794 
3795 out:
3796         if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
3797             unlikely(memcg_kmem_charge(page, gfp_mask, order) != 0)) {
3798                 __free_pages(page, order);
3799                 page = NULL;
3800         }
3801 
3802         if (kmemcheck_enabled && page)
3803                 kmemcheck_pagealloc_alloc(page, order, gfp_mask);
3804 
3805         trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);
3806 
3807         return page;
3808 }
3809 EXPORT_SYMBOL(__alloc_pages_nodemask);
3810 
3811 /*
3812  * Common helper functions.
3813  */
3814 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
3815 {
3816         struct page *page;
3817 
3818         /*
3819          * __get_free_pages() returns a 32-bit address, which cannot represent
3820          * a highmem page
3821          */
3822         VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
3823 
3824         page = alloc_pages(gfp_mask, order);
3825         if (!page)
3826                 return 0;
3827         return (unsigned long) page_address(page);
3828 }
3829 EXPORT_SYMBOL(__get_free_pages);
3830 
3831 unsigned long get_zeroed_page(gfp_t gfp_mask)
3832 {
3833         return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
3834 }
3835 EXPORT_SYMBOL(get_zeroed_page);
3836 
3837 void __free_pages(struct page *page, unsigned int order)
3838 {
3839         if (put_page_testzero(page)) {
3840                 if (order == 0)
3841                         free_hot_cold_page(page, false);
3842                 else
3843                         __free_pages_ok(page, order);
3844         }
3845 }
3846 
3847 EXPORT_SYMBOL(__free_pages);
3848 
3849 void free_pages(unsigned long addr, unsigned int order)
3850 {
3851         if (addr != 0) {
3852                 VM_BUG_ON(!virt_addr_valid((void *)addr));
3853                 __free_pages(virt_to_page((void *)addr), order);
3854         }
3855 }
3856 
3857 EXPORT_SYMBOL(free_pages);
3858 
3859 /*
3860  * Page Fragment:
3861  *  An arbitrary-length arbitrary-offset area of memory which resides
3862  *  within a 0 or higher order page.  Multiple fragments within that page
3863  *  are individually refcounted, in the page's reference counter.
3864  *
3865  * The page_frag functions below provide a simple allocation framework for
3866  * page fragments.  This is used by the network stack and network device
3867  * drivers to provide a backing region of memory for use as either an
3868  * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
3869  */
3870 static struct page *__page_frag_refill(struct page_frag_cache *nc,
3871                                        gfp_t gfp_mask)
3872 {
3873         struct page *page = NULL;
3874         gfp_t gfp = gfp_mask;
3875 
3876 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
3877         gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
3878                     __GFP_NOMEMALLOC;
3879         page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
3880                                 PAGE_FRAG_CACHE_MAX_ORDER);
3881         nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
3882 #endif
3883         if (unlikely(!page))
3884                 page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
3885 
3886         nc->va = page ? page_address(page) : NULL;
3887 
3888         return page;
3889 }
3890 
3891 void *__alloc_page_frag(struct page_frag_cache *nc,
3892                         unsigned int fragsz, gfp_t gfp_mask)
3893 {
3894         unsigned int size = PAGE_SIZE;
3895         struct page *page;
3896         int offset;
3897 
3898         if (unlikely(!nc->va)) {
3899 refill:
3900                 page = __page_frag_refill(nc, gfp_mask);
3901                 if (!page)
3902                         return NULL;
3903 
3904 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
3905                 /* if size can vary use size else just use PAGE_SIZE */
3906                 size = nc->size;
3907 #endif
3908                 /* Even if we own the page, we do not use atomic_set().
3909                  * This would break get_page_unless_zero() users.
3910                  */
3911                 page_ref_add(page, size - 1);
3912 
3913                 /* reset page count bias and offset to start of new frag */
3914                 nc->pfmemalloc = page_is_pfmemalloc(page);
3915                 nc->pagecnt_bias = size;
3916                 nc->offset = size;
3917         }
3918 
3919         offset = nc->offset - fragsz;
3920         if (unlikely(offset < 0)) {
3921                 page = virt_to_page(nc->va);
3922 
3923                 if (!page_ref_sub_and_test(page, nc->pagecnt_bias))
3924                         goto refill;
3925 
3926 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
3927                 /* if size can vary use size else just use PAGE_SIZE */
3928                 size = nc->size;
3929 #endif
3930                 /* OK, page count is 0, we can safely set it */
3931                 set_page_count(page, size);
3932 
3933                 /* reset page count bias and offset to start of new frag */
3934                 nc->pagecnt_bias = size;
3935                 offset = size - fragsz;
3936         }
3937 
3938         nc->pagecnt_bias--;
3939         nc->offset = offset;
3940 
3941         return nc->va + offset;
3942 }
3943 EXPORT_SYMBOL(__alloc_page_frag);
3944 
3945 /*
3946  * Frees a page fragment allocated out of either a compound or order 0 page.
3947  */
3948 void __free_page_frag(void *addr)
3949 {
3950         struct page *page = virt_to_head_page(addr);
3951 
3952         if (unlikely(put_page_testzero(page)))
3953                 __free_pages_ok(page, compound_order(page));
3954 }
3955 EXPORT_SYMBOL(__free_page_frag);
3956 
3957 static void *make_alloc_exact(unsigned long addr, unsigned int order,
3958                 size_t size)
3959 {
3960         if (addr) {
3961                 unsigned long alloc_end = addr + (PAGE_SIZE << order);
3962                 unsigned long used = addr + PAGE_ALIGN(size);
3963 
3964                 split_page(virt_to_page((void *)addr), order);
3965                 while (used < alloc_end) {
3966                         free_page(used);
3967                         used += PAGE_SIZE;
3968                 }
3969         }
3970         return (void *)addr;
3971 }
3972 
3973 /**
3974  * alloc_pages_exact - allocate an exact number physically-contiguous pages.
3975  * @size: the number of bytes to allocate
3976  * @gfp_mask: GFP flags for the allocation
3977  *
3978  * This function is similar to alloc_pages(), except that it allocates the
3979  * minimum number of pages to satisfy the request.  alloc_pages() can only
3980  * allocate memory in power-of-two pages.
3981  *
3982  * This function is also limited by MAX_ORDER.
3983  *
3984  * Memory allocated by this function must be released by free_pages_exact().
3985  */
3986 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
3987 {
3988         unsigned int order = get_order(size);
3989         unsigned long addr;
3990 
3991         addr = __get_free_pages(gfp_mask, order);
3992         return make_alloc_exact(addr, order, size);
3993 }
3994 EXPORT_SYMBOL(alloc_pages_exact);
3995 
3996 /**
3997  * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
3998  *                         pages on a node.
3999  * @nid: the preferred node ID where memory should be allocated
4000  * @size: the number of bytes to allocate
4001  * @gfp_mask: GFP flags for the allocation
4002  *
4003  * Like alloc_pages_exact(), but try to allocate on node nid first before falling
4004  * back.
4005  */
4006 void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
4007 {
4008         unsigned int order = get_order(size);
4009         struct page *p = alloc_pages_node(nid, gfp_mask, order);
4010         if (!p)
4011                 return NULL;
4012         return make_alloc_exact((unsigned long)page_address(p), order, size);
4013 }
4014 
4015 /**
4016  * free_pages_exact - release memory allocated via alloc_pages_exact()
4017  * @virt: the value returned by alloc_pages_exact.
4018  * @size: size of allocation, same value as passed to alloc_pages_exact().
4019  *
4020  * Release the memory allocated by a previous call to alloc_pages_exact.
4021  */
4022 void free_pages_exact(void *virt, size_t size)
4023 {
4024         unsigned long addr = (unsigned long)virt;
4025         unsigned long end = addr + PAGE_ALIGN(size);
4026 
4027         while (addr < end) {
4028                 free_page(addr);
4029                 addr += PAGE_SIZE;
4030         }
4031 }
4032 EXPORT_SYMBOL(free_pages_exact);
4033 
4034 /**
4035  * nr_free_zone_pages - count number of pages beyond high watermark
4036  * @offset: The zone index of the highest zone
4037  *
4038  * nr_free_zone_pages() counts the number of counts pages which are beyond the
4039  * high watermark within all zones at or below a given zone index.  For each
4040  * zone, the number of pages is calculated as:
4041  *     managed_pages - high_pages
4042  */
4043 static unsigned long nr_free_zone_pages(int offset)
4044 {
4045         struct zoneref *z;
4046         struct zone *zone;
4047 
4048         /* Just pick one node, since fallback list is circular */
4049         unsigned long sum = 0;
4050 
4051         struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
4052 
4053         for_each_zone_zonelist(zone, z, zonelist, offset) {
4054                 unsigned long size = zone->managed_pages;
4055                 unsigned long high = high_wmark_pages(zone);
4056                 if (size > high)
4057                         sum += size - high;
4058         }
4059 
4060         return sum;
4061 }
4062 
4063 /**
4064  * nr_free_buffer_pages - count number of pages beyond high watermark
4065  *
4066  * nr_free_buffer_pages() counts the number of pages which are beyond the high
4067  * watermark within ZONE_DMA and ZONE_NORMAL.
4068  */
4069 unsigned long nr_free_buffer_pages(void)
4070 {
4071         return nr_free_zone_pages(gfp_zone(GFP_USER));
4072 }
4073 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
4074 
4075 /**
4076  * nr_free_pagecache_pages - count number of pages beyond high watermark
4077  *
4078  * nr_free_pagecache_pages() counts the number of pages which are beyond the
4079  * high watermark within all zones.
4080  */
4081 unsigned long nr_free_pagecache_pages(void)
4082 {
4083         return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
4084 }
4085 
4086 static inline void show_node(struct zone *zone)
4087 {
4088         if (IS_ENABLED(CONFIG_NUMA))
4089                 printk("Node %d ", zone_to_nid(zone));
4090 }
4091 
4092 long si_mem_available(void)
4093 {
4094         long available;
4095         unsigned long pagecache;
4096         unsigned long wmark_low = 0;
4097         unsigned long pages[NR_LRU_LISTS];
4098         struct zone *zone;
4099         int lru;
4100 
4101         for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
4102                 pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
4103 
4104         for_each_zone(zone)
4105                 wmark_low += zone->watermark[WMARK_LOW];
4106 
4107         /*
4108          * Estimate the amount of memory available for userspace allocations,
4109          * without causing swapping.
4110          */
4111         available = global_page_state(NR_FREE_PAGES) - totalreserve_pages;
4112 
4113         /*
4114          * Not all the page cache can be freed, otherwise the system will
4115          * start swapping. Assume at least half of the page cache, or the
4116          * low watermark worth of cache, needs to stay.
4117          */
4118         pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
4119         pagecache -= min(pagecache / 2, wmark_low);
4120         available += pagecache;
4121 
4122         /*
4123          * Part of the reclaimable slab consists of items that are in use,
4124          * and cannot be freed. Cap this estimate at the low watermark.
4125          */
4126         available += global_page_state(NR_SLAB_RECLAIMABLE) -
4127                      min(global_page_state(NR_SLAB_RECLAIMABLE) / 2, wmark_low);
4128 
4129         if (available < 0)
4130                 available = 0;
4131         return available;
4132 }
4133 EXPORT_SYMBOL_GPL(si_mem_available);
4134 
4135 void si_meminfo(struct sysinfo *val)
4136 {
4137         val->totalram = totalram_pages;
4138         val->sharedram = global_node_page_state(NR_SHMEM);
4139         val->freeram = global_page_state(NR_FREE_PAGES);
4140         val->bufferram = nr_blockdev_pages();
4141         val->totalhigh = totalhigh_pages;
4142         val->freehigh = nr_free_highpages();
4143         val->mem_unit = PAGE_SIZE;
4144 }
4145 
4146 EXPORT_SYMBOL(si_meminfo);
4147 
4148 #ifdef CONFIG_NUMA
4149 void si_meminfo_node(struct sysinfo *val, int nid)
4150 {
4151         int zone_type;          /* needs to be signed */
4152         unsigned long managed_pages = 0;
4153         unsigned long managed_highpages = 0;
4154         unsigned long free_highpages = 0;
4155         pg_data_t *pgdat = NODE_DATA(nid);
4156 
4157         for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
4158                 managed_pages += pgdat->node_zones[zone_type].managed_pages;
4159         val->totalram = managed_pages;
4160         val->sharedram = node_page_state(pgdat, NR_SHMEM);
4161         val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
4162 #ifdef CONFIG_HIGHMEM
4163         for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
4164                 struct zone *zone = &pgdat->node_zones[zone_type];
4165 
4166                 if (is_highmem(zone)) {
4167                         managed_highpages += zone->managed_pages;
4168                         free_highpages += zone_page_state(zone, NR_FREE_PAGES);
4169                 }
4170         }
4171         val->totalhigh = managed_highpages;
4172         val->freehigh = free_highpages;
4173 #else
4174         val->totalhigh = managed_highpages;
4175         val->freehigh = free_highpages;
4176 #endif
4177         val->mem_unit = PAGE_SIZE;
4178 }
4179 #endif
4180 
4181 /*
4182  * Determine whether the node should be displayed or not, depending on whether
4183  * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
4184  */
4185 bool skip_free_areas_node(unsigned int flags, int nid)
4186 {
4187         bool ret = false;
4188         unsigned int cpuset_mems_cookie;
4189 
4190         if (!(flags & SHOW_MEM_FILTER_NODES))
4191                 goto out;
4192 
4193         do {
4194                 cpuset_mems_cookie = read_mems_allowed_begin();
4195                 ret = !node_isset(nid, cpuset_current_mems_allowed);
4196         } while (read_mems_allowed_retry(cpuset_mems_cookie));
4197 out:
4198         return ret;
4199 }
4200 
4201 #define K(x) ((x) << (PAGE_SHIFT-10))
4202 
4203 static void show_migration_types(unsigned char type)
4204 {
4205         static const char types[MIGRATE_TYPES] = {
4206                 [MIGRATE_UNMOVABLE]     = 'U',
4207                 [MIGRATE_MOVABLE]       = 'M',
4208                 [MIGRATE_RECLAIMABLE]   = 'E',
4209                 [MIGRATE_HIGHATOMIC]    = 'H',
4210 #ifdef CONFIG_CMA
4211                 [MIGRATE_CMA]           = 'C',
4212 #endif
4213 #ifdef CONFIG_MEMORY_ISOLATION
4214                 [MIGRATE_ISOLATE]       = 'I',
4215 #endif
4216         };
4217         char tmp[MIGRATE_TYPES + 1];
4218         char *p = tmp;
4219         int i;
4220 
4221         for (i = 0; i < MIGRATE_TYPES; i++) {
4222                 if (type & (1 << i))
4223                         *p++ = types[i];
4224         }
4225 
4226         *p = '\0';
4227         printk(KERN_CONT "(%s) ", tmp);
4228 }
4229 
4230 /*
4231  * Show free area list (used inside shift_scroll-lock stuff)
4232  * We also calculate the percentage fragmentation. We do this by counting the
4233  * memory on each free list with the exception of the first item on the list.
4234  *
4235  * Bits in @filter:
4236  * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
4237  *   cpuset.
4238  */
4239 void show_free_areas(unsigned int filter)
4240 {
4241         unsigned long free_pcp = 0;
4242         int cpu;
4243         struct zone *zone;
4244         pg_data_t *pgdat;
4245 
4246         for_each_populated_zone(zone) {
4247                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
4248                         continue;
4249 
4250                 for_each_online_cpu(cpu)
4251                         free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
4252         }
4253 
4254         printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
4255                 " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
4256                 " unevictable:%lu dirty:%lu writeback:%lu unstable:%lu\n"
4257                 " slab_reclaimable:%lu slab_unreclaimable:%lu\n"
4258                 " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
4259                 " free:%lu free_pcp:%lu free_cma:%lu\n",
4260                 global_node_page_state(NR_ACTIVE_ANON),
4261                 global_node_page_state(NR_INACTIVE_ANON),
4262                 global_node_page_state(NR_ISOLATED_ANON),
4263                 global_node_page_state(NR_ACTIVE_FILE),
4264                 global_node_page_state(NR_INACTIVE_FILE),
4265                 global_node_page_state(NR_ISOLATED_FILE),
4266                 global_node_page_state(NR_UNEVICTABLE),
4267                 global_node_page_state(NR_FILE_DIRTY),
4268                 global_node_page_state(NR_WRITEBACK),
4269                 global_node_page_state(NR_UNSTABLE_NFS),
4270                 global_page_state(NR_SLAB_RECLAIMABLE),
4271                 global_page_state(NR_SLAB_UNRECLAIMABLE),
4272                 global_node_page_state(NR_FILE_MAPPED),
4273                 global_node_page_state(NR_SHMEM),
4274                 global_page_state(NR_PAGETABLE),
4275                 global_page_state(NR_BOUNCE),
4276                 global_page_state(NR_FREE_PAGES),
4277                 free_pcp,
4278                 global_page_state(NR_FREE_CMA_PAGES));
4279 
4280         for_each_online_pgdat(pgdat) {
4281                 printk("Node %d"
4282                         " active_anon:%lukB"
4283                         " inactive_anon:%lukB"
4284                         " active_file:%lukB"
4285                         " inactive_file:%lukB"
4286                         " unevictable:%lukB"
4287                         " isolated(anon):%lukB"
4288                         " isolated(file):%lukB"
4289                         " mapped:%lukB"
4290                         " dirty:%lukB"
4291                         " writeback:%lukB"
4292                         " shmem:%lukB"
4293 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4294                         " shmem_thp: %lukB"
4295                         " shmem_pmdmapped: %lukB"
4296                         " anon_thp: %lukB"
4297 #endif
4298                         " writeback_tmp:%lukB"
4299                         " unstable:%lukB"
4300                         " pages_scanned:%lu"
4301                         " all_unreclaimable? %s"
4302                         "\n",
4303                         pgdat->node_id,
4304                         K(node_page_state(pgdat, NR_ACTIVE_ANON)),
4305                         K(node_page_state(pgdat, NR_INACTIVE_ANON)),
4306                         K(node_page_state(pgdat, NR_ACTIVE_FILE)),
4307                         K(node_page_state(pgdat, NR_INACTIVE_FILE)),
4308                         K(node_page_state(pgdat, NR_UNEVICTABLE)),
4309                         K(node_page_state(pgdat, NR_ISOLATED_ANON)),
4310                         K(node_page_state(pgdat, NR_ISOLATED_FILE)),
4311                         K(node_page_state(pgdat, NR_FILE_MAPPED)),
4312                         K(node_page_state(pgdat, NR_FILE_DIRTY)),
4313                         K(node_page_state(pgdat, NR_WRITEBACK)),
4314 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4315                         K(node_page_state(pgdat, NR_SHMEM_THPS) * HPAGE_PMD_NR),
4316                         K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)
4317                                         * HPAGE_PMD_NR),
4318                         K(node_page_state(pgdat, NR_ANON_THPS) * HPAGE_PMD_NR),
4319 #endif
4320                         K(node_page_state(pgdat, NR_SHMEM)),
4321                         K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
4322                         K(node_page_state(pgdat, NR_UNSTABLE_NFS)),
4323                         node_page_state(pgdat, NR_PAGES_SCANNED),
4324                         !pgdat_reclaimable(pgdat) ? "yes" : "no");
4325         }
4326 
4327         for_each_populated_zone(zone) {
4328                 int i;
4329 
4330                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
4331                         continue;
4332 
4333                 free_pcp = 0;
4334                 for_each_online_cpu(cpu)
4335                         free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
4336 
4337                 show_node(zone);
4338                 printk(KERN_CONT
4339                         "%s"
4340                         " free:%lukB"
4341                         " min:%lukB"
4342                         " low:%lukB"
4343                         " high:%lukB"
4344                         " active_anon:%lukB"
4345                         " inactive_anon:%lukB"
4346                         " active_file:%lukB"
4347                         " inactive_file:%lukB"
4348                         " unevictable:%lukB"
4349                         " writepending:%lukB"
4350                         " present:%lukB"
4351                         " managed:%lukB"
4352                         " mlocked:%lukB"
4353                         " slab_reclaimable:%lukB"
4354                         " slab_unreclaimable:%lukB"
4355                         " kernel_stack:%lukB"
4356                         " pagetables:%lukB"
4357                         " bounce:%lukB"
4358                         " free_pcp:%lukB"
4359                         " local_pcp:%ukB"
4360                         " free_cma:%lukB"
4361                         "\n",
4362                         zone->name,
4363                         K(zone_page_state(zone, NR_FREE_PAGES)),
4364                         K(min_wmark_pages(zone)),
4365                         K(low_wmark_pages(zone)),
4366                         K(high_wmark_pages(zone)),
4367                         K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)),
4368                         K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)),
4369                         K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
4370                         K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
4371                         K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
4372                         K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
4373                         K(zone->present_pages),
4374                         K(zone->managed_pages),
4375                         K(zone_page_state(zone, NR_MLOCK)),
4376                         K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
4377                         K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
4378                         zone_page_state(zone, NR_KERNEL_STACK_KB),
4379                         K(zone_page_state(zone, NR_PAGETABLE)),
4380                         K(zone_page_state(zone, NR_BOUNCE)),
4381                         K(free_pcp),
4382                         K(this_cpu_read(zone->pageset->pcp.count)),
4383                         K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
4384                 printk("lowmem_reserve[]:");
4385                 for (i = 0; i < MAX_NR_ZONES; i++)
4386                         printk(KERN_CONT " %ld", zone->lowmem_reserve[i]);
4387                 printk(KERN_CONT "\n");
4388         }
4389 
4390         for_each_populated_zone(zone) {
4391                 unsigned int order;
4392                 unsigned long nr[MAX_ORDER], flags, total = 0;
4393                 unsigned char types[MAX_ORDER];
4394 
4395                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
4396                         continue;
4397                 show_node(zone);
4398                 printk(KERN_CONT "%s: ", zone->name);
4399 
4400                 spin_lock_irqsave(&zone->lock, flags);
4401                 for (order = 0; order < MAX_ORDER; order++) {
4402                         struct free_area *area = &zone->free_area[order];
4403                         int type;
4404 
4405                         nr[order] = area->nr_free;
4406                         total += nr[order] << order;
4407 
4408                         types[order] = 0;
4409                         for (type = 0; type < MIGRATE_TYPES; type++) {
4410                                 if (!list_empty(&area->free_list[type]))
4411                                         types[order] |= 1 << type;
4412                         }
4413                 }
4414                 spin_unlock_irqrestore(&zone->lock, flags);
4415                 for (order = 0; order < MAX_ORDER; order++) {
4416                         printk(KERN_CONT "%lu*%lukB ",
4417                                nr[order], K(1UL) << order);
4418                         if (nr[order])
4419                                 show_migration_types(types[order]);
4420                 }
4421                 printk(KERN_CONT "= %lukB\n", K(total));
4422         }
4423 
4424         hugetlb_show_meminfo();
4425 
4426         printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
4427 
4428         show_swap_cache_info();
4429 }
4430 
4431 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
4432 {
4433         zoneref->zone = zone;
4434         zoneref->zone_idx = zone_idx(zone);
4435 }
4436 
4437 /*
4438  * Builds allocation fallback zone lists.
4439  *
4440  * Add all populated zones of a node to the zonelist.
4441  */
4442 static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
4443                                 int nr_zones)
4444 {
4445         struct zone *zone;
4446         enum zone_type zone_type = MAX_NR_ZONES;
4447 
4448         do {
4449                 zone_type--;
4450                 zone = pgdat->node_zones + zone_type;
4451                 if (managed_zone(zone)) {
4452                         zoneref_set_zone(zone,
4453                                 &zonelist->_zonerefs[nr_zones++]);
4454                         check_highest_zone(zone_type);
4455                 }
4456         } while (zone_type);
4457 
4458         return nr_zones;
4459 }
4460 
4461 
4462 /*
4463  *  zonelist_order:
4464  *  0 = automatic detection of better ordering.
4465  *  1 = order by ([node] distance, -zonetype)
4466  *  2 = order by (-zonetype, [node] distance)
4467  *
4468  *  If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
4469  *  the same zonelist. So only NUMA can configure this param.
4470  */
4471 #define ZONELIST_ORDER_DEFAULT  0
4472 #define ZONELIST_ORDER_NODE     1
4473 #define ZONELIST_ORDER_ZONE     2
4474 
4475 /* zonelist order in the kernel.
4476  * set_zonelist_order() will set this to NODE or ZONE.
4477  */
4478 static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
4479 static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
4480 
4481 
4482 #ifdef CONFIG_NUMA
4483 /* The value user specified ....changed by config */
4484 static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
4485 /* string for sysctl */
4486 #define NUMA_ZONELIST_ORDER_LEN 16
4487 char numa_zonelist_order[16] = "default";
4488 
4489 /*
4490  * interface for configure zonelist ordering.
4491  * command line option "numa_zonelist_order"
4492  *      = "[dD]efault   - default, automatic configuration.
4493  *      = "[nN]ode      - order by node locality, then by zone within node
4494  *      = "[zZ]one      - order by zone, then by locality within zone
4495  */
4496 
4497 static int __parse_numa_zonelist_order(char *s)
4498 {
4499         if (*s == 'd' || *s == 'D') {
4500                 user_zonelist_order = ZONELIST_ORDER_DEFAULT;
4501         } else if (*s == 'n' || *s == 'N') {
4502                 user_zonelist_order = ZONELIST_ORDER_NODE;
4503         } else if (*s == 'z' || *s == 'Z') {
4504                 user_zonelist_order = ZONELIST_ORDER_ZONE;
4505         } else {
4506                 pr_warn("Ignoring invalid numa_zonelist_order value:  %s\n", s);
4507                 return -EINVAL;
4508         }
4509         return 0;
4510 }
4511 
4512 static __init int setup_numa_zonelist_order(char *s)
4513 {
4514         int ret;
4515 
4516         if (!s)
4517                 return 0;
4518 
4519         ret = __parse_numa_zonelist_order(s);
4520         if (ret == 0)
4521                 strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
4522 
4523         return ret;
4524 }
4525 early_param("numa_zonelist_order", setup_numa_zonelist_order);
4526 
4527 /*
4528  * sysctl handler for numa_zonelist_order
4529  */
4530 int numa_zonelist_order_handler(struct ctl_table *table, int write,
4531                 void __user *buffer, size_t *length,
4532                 loff_t *ppos)
4533 {
4534         char saved_string[NUMA_ZONELIST_ORDER_LEN];
4535         int ret;
4536         static DEFINE_MUTEX(zl_order_mutex);
4537 
4538         mutex_lock(&zl_order_mutex);
4539         if (write) {
4540                 if (strlen((char *)table->data) >= NUMA_ZONELIST_ORDER_LEN) {
4541                         ret = -EINVAL;
4542                         goto out;
4543                 }
4544                 strcpy(saved_string, (char *)table->data);
4545         }
4546         ret = proc_dostring(table, write, buffer, length, ppos);
4547         if (ret)
4548                 goto out;
4549         if (write) {
4550                 int oldval = user_zonelist_order;
4551 
4552                 ret = __parse_numa_zonelist_order((char *)table->data);
4553                 if (ret) {
4554                         /*
4555                          * bogus value.  restore saved string
4556                          */
4557                         strncpy((char *)table->data, saved_string,
4558                                 NUMA_ZONELIST_ORDER_LEN);
4559                         user_zonelist_order = oldval;
4560                 } else if (oldval != user_zonelist_order) {
4561                         mutex_lock(&zonelists_mutex);
4562                         build_all_zonelists(NULL, NULL);
4563                         mutex_unlock(&zonelists_mutex);
4564                 }
4565         }
4566 out:
4567         mutex_unlock(&zl_order_mutex);
4568         return ret;
4569 }
4570 
4571 
4572 #define MAX_NODE_LOAD (nr_online_nodes)
4573 static int node_load[MAX_NUMNODES];
4574 
4575 /**
4576  * find_next_best_node - find the next node that should appear in a given node's fallback list
4577  * @node: node whose fallback list we're appending
4578  * @used_node_mask: nodemask_t of already used nodes
4579  *
4580  * We use a number of factors to determine which is the next node that should
4581  * appear on a given node's fallback list.  The node should not have appeared
4582  * already in @node's fallback list, and it should be the next closest node
4583  * according to the distance array (which contains arbitrary distance values
4584  * from each node to each node in the system), and should also prefer nodes
4585  * with no CPUs, since presumably they'll have very little allocation pressure
4586  * on them otherwise.
4587  * It returns -1 if no node is found.
4588  */
4589 static int find_next_best_node(int node, nodemask_t *used_node_mask)
4590 {
4591         int n, val;
4592         int min_val = INT_MAX;
4593         int best_node = NUMA_NO_NODE;
4594         const struct cpumask *tmp = cpumask_of_node(0);
4595 
4596         /* Use the local node if we haven't already */
4597         if (!node_isset(node, *used_node_mask)) {
4598                 node_set(node, *used_node_mask);
4599                 return node;
4600         }
4601 
4602         for_each_node_state(n, N_MEMORY) {
4603 
4604                 /* Don't want a node to appear more than once */
4605                 if (node_isset(n, *used_node_mask))
4606                         continue;
4607 
4608                 /* Use the distance array to find the distance */
4609                 val = node_distance(node, n);
4610 
4611                 /* Penalize nodes under us ("prefer the next node") */
4612                 val += (n < node);
4613 
4614                 /* Give preference to headless and unused nodes */
4615                 tmp = cpumask_of_node(n);
4616                 if (!cpumask_empty(tmp))
4617                         val += PENALTY_FOR_NODE_WITH_CPUS;
4618 
4619                 /* Slight preference for less loaded node */
4620                 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
4621                 val += node_load[n];
4622 
4623                 if (val < min_val) {
4624                         min_val = val;
4625                         best_node = n;
4626                 }
4627         }
4628 
4629         if (best_node >= 0)
4630                 node_set(best_node, *used_node_mask);
4631 
4632         return best_node;
4633 }
4634 
4635 
4636 /*
4637  * Build zonelists ordered by node and zones within node.
4638  * This results in maximum locality--normal zone overflows into local
4639  * DMA zone, if any--but risks exhausting DMA zone.
4640  */
4641 static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
4642 {
4643         int j;
4644         struct zonelist *zonelist;
4645 
4646         zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK];
4647         for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
4648                 ;
4649         j = build_zonelists_node(NODE_DATA(node), zonelist, j);
4650         zonelist->_zonerefs[j].zone = NULL;
4651         zonelist->_zonerefs[j].zone_idx = 0;
4652 }
4653 
4654 /*
4655  * Build gfp_thisnode zonelists
4656  */
4657 static void build_thisnode_zonelists(pg_data_t *pgdat)
4658 {
4659         int j;
4660         struct zonelist *zonelist;
4661 
4662         zonelist = &pgdat->node_zonelists[ZONELIST_NOFALLBACK];
4663         j = build_zonelists_node(pgdat, zonelist, 0);
4664         zonelist->_zonerefs[j].zone = NULL;
4665         zonelist->_zonerefs[j].zone_idx = 0;
4666 }
4667 
4668 /*
4669  * Build zonelists ordered by zone and nodes within zones.
4670  * This results in conserving DMA zone[s] until all Normal memory is
4671  * exhausted, but results in overflowing to remote node while memory
4672  * may still exist in local DMA zone.
4673  */
4674 static int node_order[MAX_NUMNODES];
4675 
4676 static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
4677 {
4678         int pos, j, node;
4679         int zone_type;          /* needs to be signed */
4680         struct zone *z;
4681         struct zonelist *zonelist;
4682 
4683         zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK];
4684         pos = 0;
4685         for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
4686                 for (j = 0; j < nr_nodes; j++) {
4687                         node = node_order[j];
4688                         z = &NODE_DATA(node)->node_zones[zone_type];
4689                         if (managed_zone(z)) {
4690                                 zoneref_set_zone(z,
4691                                         &zonelist->_zonerefs[pos++]);
4692                                 check_highest_zone(zone_type);
4693                         }
4694                 }
4695         }
4696         zonelist->_zonerefs[pos].zone = NULL;
4697         zonelist->_zonerefs[pos].zone_idx = 0;
4698 }
4699 
4700 #if defined(CONFIG_64BIT)
4701 /*
4702  * Devices that require DMA32/DMA are relatively rare and do not justify a
4703  * penalty to every machine in case the specialised case applies. Default
4704  * to Node-ordering on 64-bit NUMA machines
4705  */
4706 static int default_zonelist_order(void)
4707 {
4708         return ZONELIST_ORDER_NODE;
4709 }
4710 #else
4711 /*
4712  * On 32-bit, the Normal zone needs to be preserved for allocations accessible
4713  * by the kernel. If processes running on node 0 deplete the low memory zone
4714  * then reclaim will occur more frequency increasing stalls and potentially
4715  * be easier to OOM if a large percentage of the zone is under writeback or
4716  * dirty. The problem is significantly worse if CONFIG_HIGHPTE is not set.
4717  * Hence, default to zone ordering on 32-bit.
4718  */
4719 static int default_zonelist_order(void)
4720 {
4721         return ZONELIST_ORDER_ZONE;
4722 }
4723 #endif /* CONFIG_64BIT */
4724 
4725 static void set_zonelist_order(void)
4726 {
4727         if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
4728                 current_zonelist_order = default_zonelist_order();
4729         else
4730                 current_zonelist_order = user_zonelist_order;
4731 }
4732 
4733 static void build_zonelists(pg_data_t *pgdat)
4734 {
4735         int i, node, load;
4736         nodemask_t used_mask;
4737         int local_node, prev_node;
4738         struct zonelist *zonelist;
4739         unsigned int order = current_zonelist_order;
4740 
4741         /* initialize zonelists */
4742         for (i = 0; i < MAX_ZONELISTS; i++) {
4743                 zonelist = pgdat->node_zonelists + i;
4744                 zonelist->_zonerefs[0].zone = NULL;
4745                 zonelist->_zonerefs[0].zone_idx = 0;
4746         }
4747 
4748         /* NUMA-aware ordering of nodes */
4749         local_node = pgdat->node_id;
4750         load = nr_online_nodes;
4751         prev_node = local_node;
4752         nodes_clear(used_mask);
4753 
4754         memset(node_order, 0, sizeof(node_order));
4755         i = 0;
4756 
4757         while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
4758                 /*
4759                  * We don't want to pressure a particular node.
4760                  * So adding penalty to the first node in same
4761                  * distance group to make it round-robin.
4762                  */
4763                 if (node_distance(local_node, node) !=
4764                     node_distance(local_node, prev_node))
4765                         node_load[node] = load;
4766 
4767                 prev_node = node;
4768                 load--;
4769                 if (order == ZONELIST_ORDER_NODE)
4770                         build_zonelists_in_node_order(pgdat, node);
4771                 else
4772                         node_order[i++] = node; /* remember order */
4773         }
4774 
4775         if (order == ZONELIST_ORDER_ZONE) {
4776                 /* calculate node order -- i.e., DMA last! */
4777                 build_zonelists_in_zone_order(pgdat, i);
4778         }
4779 
4780         build_thisnode_zonelists(pgdat);
4781 }
4782 
4783 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
4784 /*
4785  * Return node id of node used for "local" allocations.
4786  * I.e., first node id of first zone in arg node's generic zonelist.
4787  * Used for initializing percpu 'numa_mem', which is used primarily
4788  * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
4789  */
4790 int local_memory_node(int node)
4791 {
4792         struct zoneref *z;
4793 
4794         z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
4795                                    gfp_zone(GFP_KERNEL),
4796                                    NULL);
4797         return z->zone->node;
4798 }
4799 #endif
4800 
4801 static void setup_min_unmapped_ratio(void);
4802 static void setup_min_slab_ratio(void);
4803 #else   /* CONFIG_NUMA */
4804 
4805 static void set_zonelist_order(void)
4806 {
4807         current_zonelist_order = ZONELIST_ORDER_ZONE;
4808 }
4809 
4810 static void build_zonelists(pg_data_t *pgdat)
4811 {
4812         int node, local_node;
4813         enum zone_type j;
4814         struct zonelist *zonelist;
4815 
4816         local_node = pgdat->node_id;
4817 
4818         zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK];
4819         j = build_zonelists_node(pgdat, zonelist, 0);
4820 
4821         /*
4822          * Now we build the zonelist so that it contains the zones
4823          * of all the other nodes.
4824          * We don't want to pressure a particular node, so when
4825          * building the zones for node N, we make sure that the
4826          * zones coming right after the local ones are those from
4827          * node N+1 (modulo N)
4828          */
4829         for (node = local_node + 1; node < MAX_NUMNODES; node++) {
4830                 if (!node_online(node))
4831                         continue;
4832                 j = build_zonelists_node(NODE_DATA(node), zonelist, j);
4833         }
4834         for (node = 0; node < local_node; node++) {
4835                 if (!node_online(node))
4836                         continue;
4837                 j = build_zonelists_node(NODE_DATA(node), zonelist, j);
4838         }
4839 
4840         zonelist->_zonerefs[j].zone = NULL;
4841         zonelist->_zonerefs[j].zone_idx = 0;
4842 }
4843 
4844 #endif  /* CONFIG_NUMA */
4845 
4846 /*
4847  * Boot pageset table. One per cpu which is going to be used for all
4848  * zones and all nodes. The parameters will be set in such a way
4849  * that an item put on a list will immediately be handed over to
4850  * the buddy list. This is safe since pageset manipulation is done
4851  * with interrupts disabled.
4852  *
4853  * The boot_pagesets must be kept even after bootup is complete for
4854  * unused processors and/or zones. They do play a role for bootstrapping
4855  * hotplugged processors.
4856  *
4857  * zoneinfo_show() and maybe other functions do
4858  * not check if the processor is online before following the pageset pointer.
4859  * Other parts of the kernel may not check if the zone is available.
4860  */
4861 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
4862 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
4863 static void setup_zone_pageset(struct zone *zone);
4864 
4865 /*
4866  * Global mutex to protect against size modification of zonelists
4867  * as well as to serialize pageset setup for the new populated zone.
4868  */
4869 DEFINE_MUTEX(zonelists_mutex);
4870 
4871 /* return values int ....just for stop_machine() */
4872 static int __build_all_zonelists(void *data)
4873 {
4874         int nid;
4875         int cpu;
4876         pg_data_t *self = data;
4877 
4878 #ifdef CONFIG_NUMA
4879         memset(node_load, 0, sizeof(node_load));
4880 #endif
4881 
4882         if (self && !node_online(self->node_id)) {
4883                 build_zonelists(self);
4884         }
4885 
4886         for_each_online_node(nid) {
4887                 pg_data_t *pgdat = NODE_DATA(nid);
4888 
4889                 build_zonelists(pgdat);
4890         }
4891 
4892         /*
4893          * Initialize the boot_pagesets that are going to be used
4894          * for bootstrapping processors. The real pagesets for
4895          * each zone will be allocated later when the per cpu
4896          * allocator is available.
4897          *
4898          * boot_pagesets are used also for bootstrapping offline
4899          * cpus if the system is already booted because the pagesets
4900          * are needed to initialize allocators on a specific cpu too.
4901          * F.e. the percpu allocator needs the page allocator which
4902          * needs the percpu allocator in order to allocate its pagesets
4903          * (a chicken-egg dilemma).
4904          */
4905         for_each_possible_cpu(cpu) {
4906                 setup_pageset(&per_cpu(boot_pageset, cpu), 0);
4907 
4908 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
4909                 /*
4910                  * We now know the "local memory node" for each node--
4911                  * i.e., the node of the first zone in the generic zonelist.
4912                  * Set up numa_mem percpu variable for on-line cpus.  During
4913                  * boot, only the boot cpu should be on-line;  we'll init the
4914                  * secondary cpus' numa_mem as they come on-line.  During
4915                  * node/memory hotplug, we'll fixup all on-line cpus.
4916                  */
4917                 if (cpu_online(cpu))
4918                         set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
4919 #endif
4920         }
4921 
4922         return 0;
4923 }
4924 
4925 static noinline void __init
4926 build_all_zonelists_init(void)
4927 {
4928         __build_all_zonelists(NULL);
4929         mminit_verify_zonelist();
4930         cpuset_init_current_mems_allowed();
4931 }
4932 
4933 /*
4934  * Called with zonelists_mutex held always
4935  * unless system_state == SYSTEM_BOOTING.
4936  *
4937  * __ref due to (1) call of __meminit annotated setup_zone_pageset
4938  * [we're only called with non-NULL zone through __meminit paths] and
4939  * (2) call of __init annotated helper build_all_zonelists_init
4940  * [protected by SYSTEM_BOOTING].
4941  */
4942 void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone)
4943 {
4944         set_zonelist_order();
4945 
4946         if (system_state == SYSTEM_BOOTING) {
4947                 build_all_zonelists_init();
4948         } else {
4949 #ifdef CONFIG_MEMORY_HOTPLUG
4950                 if (zone)
4951                         setup_zone_pageset(zone);
4952 #endif
4953                 /* we have to stop all cpus to guarantee there is no user
4954                    of zonelist */
4955                 stop_machine(__build_all_zonelists, pgdat, NULL);
4956                 /* cpuset refresh routine should be here */
4957         }
4958         vm_total_pages = nr_free_pagecache_pages();
4959         /*
4960          * Disable grouping by mobility if the number of pages in the
4961          * system is too low to allow the mechanism to work. It would be
4962          * more accurate, but expensive to check per-zone. This check is
4963          * made on memory-hotadd so a system can start with mobility
4964          * disabled and enable it later
4965          */
4966         if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
4967                 page_group_by_mobility_disabled = 1;
4968         else
4969                 page_group_by_mobility_disabled = 0;
4970 
4971         pr_info("Built %i zonelists in %s order, mobility grouping %s.  Total pages: %ld\n",
4972                 nr_online_nodes,
4973                 zonelist_order_name[current_zonelist_order],
4974                 page_group_by_mobility_disabled ? "off" : "on",
4975                 vm_total_pages);
4976 #ifdef CONFIG_NUMA
4977         pr_info("Policy zone: %s\n", zone_names[policy_zone]);
4978 #endif
4979 }
4980 
4981 /*
4982  * Initially all pages are reserved - free ones are freed
4983  * up by free_all_bootmem() once the early boot process is
4984  * done. Non-atomic initialization, single-pass.
4985  */
4986 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
4987                 unsigned long start_pfn, enum memmap_context context)
4988 {
4989         struct vmem_altmap *altmap = to_vmem_altmap(__pfn_to_phys(start_pfn));
4990         unsigned long end_pfn = start_pfn + size;
4991         pg_data_t *pgdat = NODE_DATA(nid);
4992         unsigned long pfn;
4993         unsigned long nr_initialised = 0;
4994 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4995         struct memblock_region *r = NULL, *tmp;
4996 #endif
4997 
4998         if (highest_memmap_pfn < end_pfn - 1)
4999                 highest_memmap_pfn = end_pfn - 1;
5000 
5001         /*
5002          * Honor reservation requested by the driver for this ZONE_DEVICE
5003          * memory
5004          */
5005         if (altmap && start_pfn == altmap->base_pfn)
5006                 start_pfn += altmap->reserve;
5007 
5008         for (pfn = start_pfn; pfn < end_pfn; pfn++) {
5009                 /*
5010                  * There can be holes in boot-time mem_map[]s handed to this
5011                  * function.  They do not exist on hotplugged memory.
5012                  */
5013                 if (context != MEMMAP_EARLY)
5014                         goto not_early;
5015 
5016                 if (!early_pfn_valid(pfn))
5017                         continue;
5018                 if (!early_pfn_in_nid(pfn, nid))
5019                         continue;
5020                 if (!update_defer_init(pgdat, pfn, end_pfn, &nr_initialised))
5021                         break;
5022 
5023 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5024                 /*
5025                  * Check given memblock attribute by firmware which can affect
5026                  * kernel memory layout.  If zone==ZONE_MOVABLE but memory is
5027                  * mirrored, it's an overlapped memmap init. skip it.
5028                  */
5029                 if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
5030                         if (!r || pfn >= memblock_region_memory_end_pfn(r)) {
5031                                 for_each_memblock(memory, tmp)
5032                                         if (pfn < memblock_region_memory_end_pfn(tmp))
5033                                                 break;
5034                                 r = tmp;
5035                         }
5036                         if (pfn >= memblock_region_memory_base_pfn(r) &&
5037                             memblock_is_mirror(r)) {
5038                                 /* already initialized as NORMAL */
5039                                 pfn = memblock_region_memory_end_pfn(r);
5040                                 continue;
5041                         }
5042                 }
5043 #endif
5044 
5045 not_early:
5046                 /*
5047                  * Mark the block movable so that blocks are reserved for
5048                  * movable at startup. This will force kernel allocations
5049                  * to reserve their blocks rather than leaking throughout
5050                  * the address space during boot when many long-lived
5051                  * kernel allocations are made.
5052                  *
5053                  * bitmap is created for zone's valid pfn range. but memmap
5054                  * can be created for invalid pages (for alignment)
5055                  * check here not to call set_pageblock_migratetype() against
5056                  * pfn out of zone.
5057                  */
5058                 if (!(pfn & (pageblock_nr_pages - 1))) {
5059                         struct page *page = pfn_to_page(pfn);
5060 
5061                         __init_single_page(page, pfn, zone, nid);
5062                         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5063                 } else {
5064                         __init_single_pfn(pfn, zone, nid);
5065                 }
5066         }
5067 }
5068 
5069 static void __meminit zone_init_free_lists(struct zone *zone)
5070 {
5071         unsigned int order, t;
5072         for_each_migratetype_order(order, t) {
5073                 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
5074                 zone->free_area[order].nr_free = 0;
5075         }
5076 }
5077 
5078 #ifndef __HAVE_ARCH_MEMMAP_INIT
5079 #define memmap_init(size, nid, zone, start_pfn) \
5080         memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
5081 #endif
5082 
5083 static int zone_batchsize(struct zone *zone)
5084 {
5085 #ifdef CONFIG_MMU
5086         int batch;
5087 
5088         /*
5089          * The per-cpu-pages pools are set to around 1000th of the
5090          * size of the zone.  But no more than 1/2 of a meg.
5091          *
5092          * OK, so we don't know how big the cache is.  So guess.
5093          */
5094         batch = zone->managed_pages / 1024;
5095         if (batch * PAGE_SIZE > 512 * 1024)
5096                 batch = (512 * 1024) / PAGE_SIZE;
5097         batch /= 4;             /* We effectively *= 4 below */
5098         if (batch < 1)
5099                 batch = 1;
5100 
5101         /*
5102          * Clamp the batch to a 2^n - 1 value. Having a power
5103          * of 2 value was found to be more likely to have
5104          * suboptimal cache aliasing properties in some cases.
5105          *
5106          * For example if 2 tasks are alternately allocating
5107          * batches of pages, one task can end up with a lot
5108          * of pages of one half of the possible page colors
5109          * and the other with pages of the other colors.
5110          */
5111         batch = rounddown_pow_of_two(batch + batch/2) - 1;
5112 
5113         return batch;
5114 
5115 #else
5116         /* The deferral and batching of frees should be suppressed under NOMMU
5117          * conditions.
5118          *
5119          * The problem is that NOMMU needs to be able to allocate large chunks
5120          * of contiguous memory as there's no hardware page translation to
5121          * assemble apparent contiguous memory from discontiguous pages.
5122          *
5123          * Queueing large contiguous runs of pages for batching, however,
5124          * causes the pages to actually be freed in smaller chunks.  As there
5125          * can be a significant delay between the individual batches being
5126          * recycled, this leads to the once large chunks of space being
5127          * fragmented and becoming unavailable for high-order allocations.
5128          */
5129         return 0;
5130 #endif
5131 }
5132 
5133 /*
5134  * pcp->high and pcp->batch values are related and dependent on one another:
5135  * ->batch must never be higher then ->high.
5136  * The following function updates them in a safe manner without read side
5137  * locking.
5138  *
5139  * Any new users of pcp->batch and pcp->high should ensure they can cope with
5140  * those fields changing asynchronously (acording the the above rule).
5141  *
5142  * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
5143  * outside of boot time (or some other assurance that no concurrent updaters
5144  * exist).
5145  */
5146 static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
5147                 unsigned long batch)
5148 {
5149        /* start with a fail safe value for batch */
5150         pcp->batch = 1;
5151         smp_wmb();
5152 
5153        /* Update high, then batch, in order */
5154         pcp->high = high;
5155         smp_wmb();
5156 
5157         pcp->batch = batch;
5158 }
5159 
5160 /* a companion to pageset_set_high() */
5161 static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
5162 {
5163         pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
5164 }
5165 
5166 static void pageset_init(struct per_cpu_pageset *p)
5167 {
5168         struct per_cpu_pages *pcp;
5169         int migratetype;
5170 
5171         memset(p, 0, sizeof(*p));
5172 
5173         pcp = &p->pcp;
5174         pcp->count = 0;
5175         for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
5176                 INIT_LIST_HEAD(&pcp->lists[migratetype]);
5177 }
5178 
5179 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
5180 {
5181         pageset_init(p);
5182         pageset_set_batch(p, batch);
5183 }
5184 
5185 /*
5186  * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
5187  * to the value high for the pageset p.
5188  */
5189 static void pageset_set_high(struct per_cpu_pageset *p,
5190                                 unsigned long high)
5191 {
5192         unsigned long batch = max(1UL, high / 4);
5193         if ((high / 4) > (PAGE_SHIFT * 8))
5194                 batch = PAGE_SHIFT * 8;
5195 
5196         pageset_update(&p->pcp, high, batch);
5197 }
5198 
5199 static void pageset_set_high_and_batch(struct zone *zone,
5200                                        struct per_cpu_pageset *pcp)
5201 {
5202         if (percpu_pagelist_fraction)
5203                 pageset_set_high(pcp,
5204                         (zone->managed_pages /
5205                                 percpu_pagelist_fraction));
5206         else
5207                 pageset_set_batch(pcp, zone_batchsize(zone));
5208 }
5209 
5210 static void __meminit zone_pageset_init(struct zone *zone, int cpu)
5211 {
5212         struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
5213 
5214         pageset_init(pcp);
5215         pageset_set_high_and_batch(zone, pcp);
5216 }
5217 
5218 static void __meminit setup_zone_pageset(struct zone *zone)
5219 {
5220         int cpu;
5221         zone->pageset = alloc_percpu(struct per_cpu_pageset);
5222         for_each_possible_cpu(cpu)
5223                 zone_pageset_init(zone, cpu);
5224 }
5225 
5226 /*
5227  * Allocate per cpu pagesets and initialize them.
5228  * Before this call only boot pagesets were available.
5229  */
5230 void __init setup_per_cpu_pageset(void)
5231 {
5232         struct pglist_data *pgdat;
5233         struct zone *zone;
5234 
5235         for_each_populated_zone(zone)
5236                 setup_zone_pageset(zone);
5237 
5238         for_each_online_pgdat(pgdat)
5239                 pgdat->per_cpu_nodestats =
5240                         alloc_percpu(struct per_cpu_nodestat);
5241 }
5242 
5243 static __meminit void zone_pcp_init(struct zone *zone)
5244 {
5245         /*
5246          * per cpu subsystem is not up at this point. The following code
5247          * relies on the ability of the linker to provide the
5248          * offset of a (static) per cpu variable into the per cpu area.
5249          */
5250         zone->pageset = &boot_pageset;
5251 
5252         if (populated_zone(zone))
5253                 printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%u\n",
5254                         zone->name, zone->present_pages,
5255                                          zone_batchsize(zone));
5256 }
5257 
5258 int __meminit init_currently_empty_zone(struct zone *zone,
5259                                         unsigned long zone_start_pfn,
5260                                         unsigned long size)
5261 {
5262         struct pglist_data *pgdat = zone->zone_pgdat;
5263 
5264         pgdat->nr_zones = zone_idx(zone) + 1;
5265 
5266         zone->zone_start_pfn = zone_start_pfn;
5267 
5268         mminit_dprintk(MMINIT_TRACE, "memmap_init",
5269                         "Initialising map node %d zone %lu pfns %lu -> %lu\n",
5270                         pgdat->node_id,
5271                         (unsigned long)zone_idx(zone),
5272                         zone_start_pfn, (zone_start_pfn + size));
5273 
5274         zone_init_free_lists(zone);
5275         zone->initialized = 1;
5276 
5277         return 0;
5278 }
5279 
5280 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5281 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
5282 
5283 /*
5284  * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
5285  */
5286 int __meminit __early_pfn_to_nid(unsigned long pfn,
5287                                         struct mminit_pfnnid_cache *state)
5288 {
5289         unsigned long start_pfn, end_pfn;
5290         int nid;
5291 
5292         if (state->last_start <= pfn && pfn < state->last_end)
5293                 return state->last_nid;
5294 
5295         nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
5296         if (nid != -1) {
5297                 state->last_start = start_pfn;
5298                 state->last_end = end_pfn;
5299                 state->last_nid = nid;
5300         }
5301 
5302         return nid;
5303 }
5304 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
5305 
5306 /**
5307  * free_bootmem_with_active_regions - Call memblock_free_early_nid for each active range
5308  * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
5309  * @max_low_pfn: The highest PFN that will be passed to memblock_free_early_nid
5310  *
5311  * If an architecture guarantees that all ranges registered contain no holes
5312  * and may be freed, this this function may be used instead of calling
5313  * memblock_free_early_nid() manually.
5314  */
5315 void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
5316 {
5317         unsigned long start_pfn, end_pfn;
5318         int i, this_nid;
5319 
5320         for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
5321                 start_pfn = min(start_pfn, max_low_pfn);
5322                 end_pfn = min(end_pfn, max_low_pfn);
5323 
5324                 if (start_pfn < end_pfn)
5325                         memblock_free_early_nid(PFN_PHYS(start_pfn),
5326                                         (end_pfn - start_pfn) << PAGE_SHIFT,
5327                                         this_nid);
5328         }
5329 }
5330 
5331 /**
5332  * sparse_memory_present_with_active_regions - Call memory_present for each active range
5333  * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
5334  *
5335  * If an architecture guarantees that all ranges registered contain no holes and may
5336  * be freed, this function may be used instead of calling memory_present() manually.
5337  */
5338 void __init sparse_memory_present_with_active_regions(int nid)
5339 {
5340         unsigned long start_pfn, end_pfn;
5341         int i, this_nid;
5342 
5343         for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
5344                 memory_present(this_nid, start_pfn, end_pfn);
5345 }
5346 
5347 /**
5348  * get_pfn_range_for_nid - Return the start and end page frames for a node
5349  * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
5350  * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
5351  * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
5352  *
5353  * It returns the start and end page frame of a node based on information
5354  * provided by memblock_set_node(). If called for a node
5355  * with no available memory, a warning is printed and the start and end
5356  * PFNs will be 0.
5357  */
5358 void __meminit get_pfn_range_for_nid(unsigned int nid,
5359                         unsigned long *start_pfn, unsigned long *end_pfn)
5360 {
5361         unsigned long this_start_pfn, this_end_pfn;
5362         int i;
5363 
5364         *start_pfn = -1UL;
5365         *end_pfn = 0;
5366 
5367         for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
5368                 *start_pfn = min(*start_pfn, this_start_pfn);
5369                 *end_pfn = max(*end_pfn, this_end_pfn);
5370         }
5371 
5372         if (*start_pfn == -1UL)
5373                 *start_pfn = 0;
5374 }
5375 
5376 /*
5377  * This finds a zone that can be used for ZONE_MOVABLE pages. The
5378  * assumption is made that zones within a node are ordered in monotonic
5379  * increasing memory addresses so that the "highest" populated zone is used
5380  */
5381 static void __init find_usable_zone_for_movable(void)
5382 {
5383         int zone_index;
5384         for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
5385                 if (zone_index == ZONE_MOVABLE)
5386                         continue;
5387 
5388                 if (arch_zone_highest_possible_pfn[zone_index] >
5389                                 arch_zone_lowest_possible_pfn[zone_index])
5390                         break;
5391         }
5392 
5393         VM_BUG_ON(zone_index == -1);
5394         movable_zone = zone_index;
5395 }
5396 
5397 /*
5398  * The zone ranges provided by the architecture do not include ZONE_MOVABLE
5399  * because it is sized independent of architecture. Unlike the other zones,
5400  * the starting point for ZONE_MOVABLE is not fixed. It may be different
5401  * in each node depending on the size of each node and how evenly kernelcore
5402  * is distributed. This helper function adjusts the zone ranges
5403  * provided by the architecture for a given node by using the end of the
5404  * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
5405  * zones within a node are in order of monotonic increases memory addresses
5406  */
5407 static void __meminit adjust_zone_range_for_zone_movable(int nid,
5408                                         unsigned long zone_type,
5409                                         unsigned long node_start_pfn,
5410                                         unsigned long node_end_pfn,
5411                                         unsigned long *zone_start_pfn,
5412                                         unsigned long *zone_end_pfn)
5413 {
5414         /* Only adjust if ZONE_MOVABLE is on this node */
5415         if (zone_movable_pfn[nid]) {
5416                 /* Size ZONE_MOVABLE */
5417                 if (zone_type == ZONE_MOVABLE) {
5418                         *zone_start_pfn = zone_movable_pfn[nid];
5419                         *zone_end_pfn = min(node_end_pfn,
5420                                 arch_zone_highest_possible_pfn[movable_zone]);
5421 
5422                 /* Adjust for ZONE_MOVABLE starting within this range */
5423                 } else if (!mirrored_kernelcore &&
5424                         *zone_start_pfn < zone_movable_pfn[nid] &&
5425                         *zone_end_pfn > zone_movable_pfn[nid]) {
5426                         *zone_end_pfn = zone_movable_pfn[nid];
5427 
5428                 /* Check if this whole range is within ZONE_MOVABLE */
5429                 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
5430                         *zone_start_pfn = *zone_end_pfn;
5431         }
5432 }
5433 
5434 /*
5435  * Return the number of pages a zone spans in a node, including holes
5436  * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
5437  */
5438 static unsigned long __meminit zone_spanned_pages_in_node(int nid,
5439                                         unsigned long zone_type,
5440                                         unsigned long node_start_pfn,
5441                                         unsigned long node_end_pfn,
5442                                         unsigned long *zone_start_pfn,
5443                                         unsigned long *zone_end_pfn,
5444                                         unsigned long *ignored)
5445 {
5446         /* When hotadd a new node from cpu_up(), the node should be empty */
5447         if (!node_start_pfn && !node_end_pfn)
5448                 return 0;
5449 
5450         /* Get the start and end of the zone */
5451         *zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
5452         *zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
5453         adjust_zone_range_for_zone_movable(nid, zone_type,
5454                                 node_start_pfn, node_end_pfn,
5455                                 zone_start_pfn, zone_end_pfn);
5456 
5457         /* Check that this node has pages within the zone's required range */
5458         if (*zone_end_pfn < node_start_pfn || *zone_start_pfn > node_end_pfn)
5459                 return 0;
5460 
5461         /* Move the zone boundaries inside the node if necessary */
5462         *zone_end_pfn = min(*zone_end_pfn, node_end_pfn);
5463         *zone_start_pfn = max(*zone_start_pfn, node_start_pfn);
5464 
5465         /* Return the spanned pages */
5466         return *zone_end_pfn - *zone_start_pfn;
5467 }
5468 
5469 /*
5470  * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
5471  * then all holes in the requested range will be accounted for.
5472  */
5473 unsigned long __meminit __absent_pages_in_range(int nid,
5474                                 unsigned long range_start_pfn,
5475                                 unsigned long range_end_pfn)
5476 {
5477         unsigned long nr_absent = range_end_pfn - range_start_pfn;
5478         unsigned long start_pfn, end_pfn;
5479         int i;
5480 
5481         for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
5482                 start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
5483                 end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
5484                 nr_absent -= end_pfn - start_pfn;
5485         }
5486         return nr_absent;
5487 }
5488 
5489 /**
5490  * absent_pages_in_range - Return number of page frames in holes within a range
5491  * @start_pfn: The start PFN to start searching for holes
5492  * @end_pfn: The end PFN to stop searching for holes
5493  *
5494  * It returns the number of pages frames in memory holes within a range.
5495  */
5496 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
5497                                                         unsigned long end_pfn)
5498 {
5499         return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
5500 }
5501 
5502 /* Return the number of page frames in holes in a zone on a node */
5503 static unsigned long __meminit zone_absent_pages_in_node(int nid,
5504                                         unsigned long zone_type,
5505                                         unsigned long node_start_pfn,
5506                                         unsigned long node_end_pfn,
5507                                         unsigned long *ignored)
5508 {
5509         unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
5510         unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
5511         unsigned long zone_start_pfn, zone_end_pfn;
5512         unsigned long nr_absent;
5513 
5514         /* When hotadd a new node from cpu_up(), the node should be empty */
5515         if (!node_start_pfn && !node_end_pfn)
5516                 return 0;
5517 
5518         zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
5519         zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
5520 
5521         adjust_zone_range_for_zone_movable(nid, zone_type,
5522                         node_start_pfn, node_end_pfn,
5523                         &zone_start_pfn, &zone_end_pfn);
5524         nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
5525 
5526         /*
5527          * ZONE_MOVABLE handling.
5528          * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
5529          * and vice versa.
5530          */
5531         if (mirrored_kernelcore && zone_movable_pfn[nid]) {
5532                 unsigned long start_pfn, end_pfn;
5533                 struct memblock_region *r;
5534 
5535                 for_each_memblock(memory, r) {
5536                         start_pfn = clamp(memblock_region_memory_base_pfn(r),
5537                                           zone_start_pfn, zone_end_pfn);
5538                         end_pfn = clamp(memblock_region_memory_end_pfn(r),
5539                                         zone_start_pfn, zone_end_pfn);
5540 
5541                         if (zone_type == ZONE_MOVABLE &&
5542                             memblock_is_mirror(r))
5543                                 nr_absent += end_pfn - start_pfn;
5544 
5545                         if (zone_type == ZONE_NORMAL &&
5546                             !memblock_is_mirror(r))
5547                                 nr_absent += end_pfn - start_pfn;
5548                 }
5549         }
5550 
5551         return nr_absent;
5552 }
5553 
5554 #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5555 static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
5556                                         unsigned long zone_type,
5557                                         unsigned long node_start_pfn,
5558                                         unsigned long node_end_pfn,
5559                                         unsigned long *zone_start_pfn,
5560                                         unsigned long *zone_end_pfn,
5561                                         unsigned long *zones_size)
5562 {
5563         unsigned int zone;
5564 
5565         *zone_start_pfn = node_start_pfn;
5566         for (zone = 0; zone < zone_type; zone++)
5567                 *zone_start_pfn += zones_size[zone];
5568 
5569         *zone_end_pfn = *zone_start_pfn + zones_size[zone_type];
5570 
5571         return zones_size[zone_type];
5572 }
5573 
5574 static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
5575                                                 unsigned long zone_type,
5576                                                 unsigned long node_start_pfn,
5577                                                 unsigned long node_end_pfn,
5578                                                 unsigned long *zholes_size)
5579 {
5580         if (!zholes_size)
5581                 return 0;
5582 
5583         return zholes_size[zone_type];
5584 }
5585 
5586 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5587 
5588 static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
5589                                                 unsigned long node_start_pfn,
5590                                                 unsigned long node_end_pfn,
5591                                                 unsigned long *zones_size,
5592                                                 unsigned long *zholes_size)
5593 {
5594         unsigned long realtotalpages = 0, totalpages = 0;
5595         enum zone_type i;
5596 
5597         for (i = 0; i < MAX_NR_ZONES; i++) {
5598                 struct zone *zone = pgdat->node_zones + i;
5599                 unsigned long zone_start_pfn, zone_end_pfn;
5600                 unsigned long size, real_size;
5601 
5602                 size = zone_spanned_pages_in_node(pgdat->node_id, i,
5603                                                   node_start_pfn,
5604                                                   node_end_pfn,
5605                                                   &zone_start_pfn,
5606                                                   &zone_end_pfn,
5607                                                   zones_size);
5608                 real_size = size - zone_absent_pages_in_node(pgdat->node_id, i,
5609                                                   node_start_pfn, node_end_pfn,
5610                                                   zholes_size);
5611                 if (size)
5612                         zone->zone_start_pfn = zone_start_pfn;
5613                 else
5614                         zone->zone_start_pfn = 0;
5615                 zone->spanned_pages = size;
5616                 zone->present_pages = real_size;
5617 
5618                 totalpages += size;
5619                 realtotalpages += real_size;
5620         }
5621 
5622         pgdat->node_spanned_pages = totalpages;
5623         pgdat->node_present_pages = realtotalpages;
5624         printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
5625                                                         realtotalpages);
5626 }
5627 
5628 #ifndef CONFIG_SPARSEMEM
5629 /*
5630  * Calculate the size of the zone->blockflags rounded to an unsigned long
5631  * Start by making sure zonesize is a multiple of pageblock_order by rounding
5632  * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
5633  * round what is now in bits to nearest long in bits, then return it in
5634  * bytes.
5635  */
5636 static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
5637 {
5638         unsigned long usemapsize;
5639 
5640         zonesize += zone_start_pfn & (pageblock_nr_pages-1);
5641         usemapsize = roundup(zonesize, pageblock_nr_pages);
5642         usemapsize = usemapsize >> pageblock_order;
5643         usemapsize *= NR_PAGEBLOCK_BITS;
5644         usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
5645 
5646         return usemapsize / 8;
5647 }
5648 
5649 static void __init setup_usemap(struct pglist_data *pgdat,
5650                                 struct zone *zone,
5651                                 unsigned long zone_start_pfn,
5652                                 unsigned long zonesize)
5653 {
5654         unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
5655         zone->pageblock_flags = NULL;
5656         if (usemapsize)
5657                 zone->pageblock_flags =
5658                         memblock_virt_alloc_node_nopanic(usemapsize,
5659                                                          pgdat->node_id);
5660 }
5661 #else
5662 static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
5663                                 unsigned long zone_start_pfn, unsigned long zonesize) {}
5664 #endif /* CONFIG_SPARSEMEM */
5665 
5666 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
5667 
5668 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
5669 void __paginginit set_pageblock_order(void)
5670 {
5671         unsigned int order;
5672 
5673         /* Check that pageblock_nr_pages has not already been setup */
5674         if (pageblock_order)
5675                 return;
5676 
5677         if (HPAGE_SHIFT > PAGE_SHIFT)
5678                 order = HUGETLB_PAGE_ORDER;
5679         else
5680                 order = MAX_ORDER - 1;
5681 
5682         /*
5683          * Assume the largest contiguous order of interest is a huge page.
5684          * This value may be variable depending on boot parameters on IA64 and
5685          * powerpc.
5686          */
5687         pageblock_order = order;
5688 }
5689 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
5690 
5691 /*
5692  * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
5693  * is unused as pageblock_order is set at compile-time. See
5694  * include/linux/pageblock-flags.h for the values of pageblock_order based on
5695  * the kernel config
5696  */
5697 void __paginginit set_pageblock_order(void)
5698 {
5699 }
5700 
5701 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
5702 
5703 static unsigned long __paginginit calc_memmap_size(unsigned long spanned_pages,
5704                                                    unsigned long present_pages)
5705 {
5706         unsigned long pages = spanned_pages;
5707 
5708         /*
5709          * Provide a more accurate estimation if there are holes within
5710          * the zone and SPARSEMEM is in use. If there are holes within the
5711          * zone, each populated memory region may cost us one or two extra
5712          * memmap pages due to alignment because memmap pages for each
5713          * populated regions may not naturally algined on page boundary.
5714          * So the (present_pages >> 4) heuristic is a tradeoff for that.
5715          */
5716         if (spanned_pages > present_pages + (present_pages >> 4) &&
5717             IS_ENABLED(CONFIG_SPARSEMEM))
5718                 pages = present_pages;
5719 
5720         return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
5721 }
5722 
5723 /*
5724  * Set up the zone data structures:
5725  *   - mark all pages reserved
5726  *   - mark all memory queues empty
5727  *   - clear the memory bitmaps
5728  *
5729  * NOTE: pgdat should get zeroed by caller.
5730  */
5731 static void __paginginit free_area_init_core(struct pglist_data *pgdat)
5732 {
5733         enum zone_type j;
5734         int nid = pgdat->node_id;
5735         int ret;
5736 
5737         pgdat_resize_init(pgdat);
5738 #ifdef CONFIG_NUMA_BALANCING
5739         spin_lock_init(&pgdat->numabalancing_migrate_lock);
5740         pgdat->numabalancing_migrate_nr_pages = 0;
5741         pgdat->numabalancing_migrate_next_window = jiffies;
5742 #endif
5743 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5744         spin_lock_init(&pgdat->split_queue_lock);
5745         INIT_LIST_HEAD(&pgdat->split_queue);
5746         pgdat->split_queue_len = 0;
5747 #endif
5748         init_waitqueue_head(&pgdat->kswapd_wait);
5749         init_waitqueue_head(&pgdat->pfmemalloc_wait);
5750 #ifdef CONFIG_COMPACTION
5751         init_waitqueue_head(&pgdat->kcompactd_wait);
5752 #endif
5753         pgdat_page_ext_init(pgdat);
5754         spin_lock_init(&pgdat->lru_lock);
5755         lruvec_init(node_lruvec(pgdat));
5756 
5757         for (j = 0; j < MAX_NR_ZONES; j++) {
5758                 struct zone *zone = pgdat->node_zones + j;
5759                 unsigned long size, realsize, freesize, memmap_pages;
5760                 unsigned long zone_start_pfn = zone->zone_start_pfn;
5761 
5762                 size = zone->spanned_pages;
5763                 realsize = freesize = zone->present_pages;
5764 
5765                 /*
5766                  * Adjust freesize so that it accounts for how much memory
5767                  * is used by this zone for memmap. This affects the watermark
5768                  * and per-cpu initialisations
5769                  */
5770                 memmap_pages = calc_memmap_size(size, realsize);
5771                 if (!is_highmem_idx(j)) {
5772                         if (freesize >= memmap_pages) {
5773                                 freesize -= memmap_pages;
5774                                 if (memmap_pages)
5775                                         printk(KERN_DEBUG
5776                                                "  %s zone: %lu pages used for memmap\n",
5777                                                zone_names[j], memmap_pages);
5778                         } else
5779                                 pr_warn("  %s zone: %lu pages exceeds freesize %lu\n",
5780                                         zone_names[j], memmap_pages, freesize);
5781                 }
5782 
5783                 /* Account for reserved pages */
5784                 if (j == 0 && freesize > dma_reserve) {
5785                         freesize -= dma_reserve;
5786                         printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
5787                                         zone_names[0], dma_reserve);
5788                 }
5789 
5790                 if (!is_highmem_idx(j))
5791                         nr_kernel_pages += freesize;
5792                 /* Charge for highmem memmap if there are enough kernel pages */
5793                 else if (nr_kernel_pages > memmap_pages * 2)
5794                         nr_kernel_pages -= memmap_pages;
5795                 nr_all_pages += freesize;
5796 
5797                 /*
5798                  * Set an approximate value for lowmem here, it will be adjusted
5799                  * when the bootmem allocator frees pages into the buddy system.
5800                  * And all highmem pages will be managed by the buddy system.
5801                  */
5802                 zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
5803 #ifdef CONFIG_NUMA
5804                 zone->node = nid;
5805 #endif
5806                 zone->name = zone_names[j];
5807                 zone->zone_pgdat = pgdat;
5808                 spin_lock_init(&zone->lock);
5809                 zone_seqlock_init(zone);
5810                 zone_pcp_init(zone);
5811 
5812                 if (!size)
5813                         continue;
5814 
5815                 set_pageblock_order();
5816                 setup_usemap(pgdat, zone, zone_start_pfn, size);
5817                 ret = init_currently_empty_zone(zone, zone_start_pfn, size);
5818                 BUG_ON(ret);
5819                 memmap_init(size, nid, j, zone_start_pfn);
5820         }
5821 }
5822 
5823 static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
5824 {
5825         unsigned long __maybe_unused start = 0;
5826         unsigned long __maybe_unused offset = 0;
5827 
5828         /* Skip empty nodes */
5829         if (!pgdat->node_spanned_pages)
5830                 return;
5831 
5832 #ifdef CONFIG_FLAT_NODE_MEM_MAP
5833         start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
5834         offset = pgdat->node_start_pfn - start;
5835         /* ia64 gets its own node_mem_map, before this, without bootmem */
5836         if (!pgdat->node_mem_map) {
5837                 unsigned long size, end;
5838                 struct page *map;
5839 
5840                 /*
5841                  * The zone's endpoints aren't required to be MAX_ORDER
5842                  * aligned but the node_mem_map endpoints must be in order
5843                  * for the buddy allocator to function correctly.
5844                  */
5845                 end = pgdat_end_pfn(pgdat);
5846                 end = ALIGN(end, MAX_ORDER_NR_PAGES);
5847                 size =  (end - start) * sizeof(struct page);
5848                 map = alloc_remap(pgdat->node_id, size);
5849                 if (!map)
5850                         map = memblock_virt_alloc_node_nopanic(size,
5851                                                                pgdat->node_id);
5852                 pgdat->node_mem_map = map + offset;
5853         }
5854 #ifndef CONFIG_NEED_MULTIPLE_NODES
5855         /*
5856          * With no DISCONTIG, the global mem_map is just set as node 0's
5857          */
5858         if (pgdat == NODE_DATA(0)) {
5859                 mem_map = NODE_DATA(0)->node_mem_map;
5860 #if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM)
5861                 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
5862                         mem_map -= offset;
5863 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5864         }
5865 #endif
5866 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
5867 }
5868 
5869 void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
5870                 unsigned long node_start_pfn, unsigned long *zholes_size)
5871 {
5872         pg_data_t *pgdat = NODE_DATA(nid);
5873         unsigned long start_pfn = 0;
5874         unsigned long end_pfn = 0;
5875 
5876         /* pg_data_t should be reset to zero when it's allocated */
5877         WARN_ON(pgdat->nr_zones || pgdat->kswapd_classzone_idx);
5878 
5879         reset_deferred_meminit(pgdat);
5880         pgdat->node_id = nid;
5881         pgdat->node_start_pfn = node_start_pfn;
5882         pgdat->per_cpu_nodestats = NULL;
5883 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5884         get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
5885         pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
5886                 (u64)start_pfn << PAGE_SHIFT,
5887                 end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
5888 #else
5889         start_pfn = node_start_pfn;
5890 #endif
5891         calculate_node_totalpages(pgdat, start_pfn, end_pfn,
5892                                   zones_size, zholes_size);
5893 
5894         alloc_node_mem_map(pgdat);
5895 #ifdef CONFIG_FLAT_NODE_MEM_MAP
5896         printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
5897                 nid, (unsigned long)pgdat,
5898                 (unsigned long)pgdat->node_mem_map);
5899 #endif
5900 
5901         free_area_init_core(pgdat);
5902 }
5903 
5904 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5905 
5906 #if MAX_NUMNODES > 1
5907 /*
5908  * Figure out the number of possible node ids.
5909  */
5910 void __init setup_nr_node_ids(void)
5911 {
5912         unsigned int highest;
5913 
5914         highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES);
5915         nr_node_ids = highest + 1;
5916 }
5917 #endif
5918 
5919 /**
5920  * node_map_pfn_alignment - determine the maximum internode alignment
5921  *
5922  * This function should be called after node map is populated and sorted.
5923  * It calculates the maximum power of two alignment which can distinguish
5924  * all the nodes.
5925  *
5926  * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
5927  * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)).  If the
5928  * nodes are shifted by 256MiB, 256MiB.  Note that if only the last node is
5929  * shifted, 1GiB is enough and this function will indicate so.
5930  *
5931  * This is used to test whether pfn -> nid mapping of the chosen memory
5932  * model has fine enough granularity to avoid incorrect mapping for the
5933  * populated node map.
5934  *
5935  * Returns the determined alignment in pfn's.  0 if there is no alignment
5936  * requirement (single node).
5937  */
5938 unsigned long __init node_map_pfn_alignment(void)
5939 {
5940         unsigned long accl_mask = 0, last_end = 0;
5941         unsigned long start, end, mask;
5942         int last_nid = -1;
5943         int i, nid;
5944 
5945         for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
5946                 if (!start || last_nid < 0 || last_nid == nid) {
5947                         last_nid = nid;
5948                         last_end = end;
5949                         continue;
5950                 }
5951 
5952                 /*
5953                  * Start with a mask granular enough to pin-point to the
5954                  * start pfn and tick off bits one-by-one until it becomes
5955                  * too coarse to separate the current node from the last.
5956                  */
5957                 mask = ~((1 << __ffs(start)) - 1);
5958                 while (mask && last_end <= (start & (mask << 1)))
5959                         mask <<= 1;
5960 
5961                 /* accumulate all internode masks */
5962                 accl_mask |= mask;
5963         }
5964 
5965         /* convert mask to number of pages */
5966         return ~accl_mask + 1;
5967 }
5968 
5969 /* Find the lowest pfn for a node */
5970 static unsigned long __init find_min_pfn_for_node(int nid)
5971 {
5972         unsigned long min_pfn = ULONG_MAX;
5973         unsigned long start_pfn;
5974         int i;
5975 
5976         for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
5977                 min_pfn = min(min_pfn, start_pfn);
5978 
5979         if (min_pfn == ULONG_MAX) {
5980                 pr_warn("Could not find start_pfn for node %d\n", nid);
5981                 return 0;
5982         }
5983 
5984         return min_pfn;
5985 }
5986 
5987 /**
5988  * find_min_pfn_with_active_regions - Find the minimum PFN registered
5989  *
5990  * It returns the minimum PFN based on information provided via
5991  * memblock_set_node().
5992  */
5993 unsigned long __init find_min_pfn_with_active_regions(void)
5994 {
5995         return find_min_pfn_for_node(MAX_NUMNODES);
5996 }
5997 
5998 /*
5999  * early_calculate_totalpages()
6000  * Sum pages in active regions for movable zone.
6001  * Populate N_MEMORY for calculating usable_nodes.
6002  */
6003 static unsigned long __init early_calculate_totalpages(void)
6004 {
6005         unsigned long totalpages = 0;
6006         unsigned long start_pfn, end_pfn;
6007         int i, nid;
6008 
6009         for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
6010                 unsigned long pages = end_pfn - start_pfn;
6011 
6012                 totalpages += pages;
6013                 if (pages)
6014                         node_set_state(nid, N_MEMORY);
6015         }
6016         return totalpages;
6017 }
6018 
6019 /*
6020  * Find the PFN the Movable zone begins in each node. Kernel memory
6021  * is spread evenly between nodes as long as the nodes have enough
6022  * memory. When they don't, some nodes will have more kernelcore than
6023  * others
6024  */
6025 static void __init find_zone_movable_pfns_for_nodes(void)
6026 {
6027         int i, nid;
6028         unsigned long usable_startpfn;
6029         unsigned long kernelcore_node, kernelcore_remaining;
6030         /* save the state before borrow the nodemask */
6031         nodemask_t saved_node_state = node_states[N_MEMORY];
6032         unsigned long totalpages = early_calculate_totalpages();
6033         int usable_nodes = nodes_weight(node_states[N_MEMORY]);
6034         struct memblock_region *r;
6035 
6036         /* Need to find movable_zone earlier when movable_node is specified. */
6037         find_usable_zone_for_movable();
6038 
6039         /*
6040          * If movable_node is specified, ignore kernelcore and movablecore
6041          * options.
6042          */
6043         if (movable_node_is_enabled()) {
6044                 for_each_memblock(memory, r) {
6045                         if (!memblock_is_hotpluggable(r))
6046                                 continue;
6047 
6048                         nid = r->nid;
6049 
6050                         usable_startpfn = PFN_DOWN(r->base);
6051                         zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
6052                                 min(usable_startpfn, zone_movable_pfn[nid]) :
6053                                 usable_startpfn;
6054                 }
6055 
6056                 goto out2;
6057         }
6058 
6059         /*
6060          * If kernelcore=mirror is specified, ignore movablecore option
6061          */
6062         if (mirrored_kernelcore) {
6063                 bool mem_below_4gb_not_mirrored = false;
6064 
6065                 for_each_memblock(memory, r) {
6066                         if (memblock_is_mirror(r))
6067                                 continue;
6068 
6069                         nid = r->nid;
6070 
6071                         usable_startpfn = memblock_region_memory_base_pfn(r);
6072 
6073                         if (usable_startpfn < 0x100000) {
6074                                 mem_below_4gb_not_mirrored = true;
6075                                 continue;
6076                         }
6077 
6078                         zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
6079                                 min(usable_startpfn, zone_movable_pfn[nid]) :
6080                                 usable_startpfn;
6081                 }
6082 
6083                 if (mem_below_4gb_not_mirrored)
6084                         pr_warn("This configuration results in unmirrored kernel memory.");
6085 
6086                 goto out2;
6087         }
6088 
6089         /*
6090          * If movablecore=nn[KMG] was specified, calculate what size of
6091          * kernelcore that corresponds so that memory usable for
6092          * any allocation type is evenly spread. If both kernelcore
6093          * and movablecore are specified, then the value of kernelcore
6094          * will be used for required_kernelcore if it's greater than
6095          * what movablecore would have allowed.
6096          */
6097         if (required_movablecore) {
6098                 unsigned long corepages;
6099 
6100                 /*
6101                  * Round-up so that ZONE_MOVABLE is at least as large as what
6102                  * was requested by the user
6103                  */
6104                 required_movablecore =
6105                         roundup(required_movablecore, MAX_ORDER_NR_PAGES);
6106                 required_movablecore = min(totalpages, required_movablecore);
6107                 corepages = totalpages - required_movablecore;
6108 
6109                 required_kernelcore = max(required_kernelcore, corepages);
6110         }
6111 
6112         /*
6113          * If kernelcore was not specified or kernelcore size is larger
6114          * than totalpages, there is no ZONE_MOVABLE.
6115          */
6116         if (!required_kernelcore || required_kernelcore >= totalpages)
6117                 goto out;
6118 
6119         /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
6120         usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
6121 
6122 restart:
6123         /* Spread kernelcore memory as evenly as possible throughout nodes */
6124         kernelcore_node = required_kernelcore / usable_nodes;
6125         for_each_node_state(nid, N_MEMORY) {
6126                 unsigned long start_pfn, end_pfn;
6127 
6128                 /*
6129                  * Recalculate kernelcore_node if the division per node
6130                  * now exceeds what is necessary to satisfy the requested
6131                  * amount of memory for the kernel
6132                  */
6133                 if (required_kernelcore < kernelcore_node)
6134                         kernelcore_node = required_kernelcore / usable_nodes;
6135 
6136                 /*
6137                  * As the map is walked, we track how much memory is usable
6138                  * by the kernel using kernelcore_remaining. When it is
6139                  * 0, the rest of the node is usable by ZONE_MOVABLE
6140                  */
6141                 kernelcore_remaining = kernelcore_node;
6142 
6143                 /* Go through each range of PFNs within this node */
6144                 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
6145                         unsigned long size_pages;
6146 
6147                         start_pfn = max(start_pfn, zone_movable_pfn[nid]);
6148                         if (start_pfn >= end_pfn)
6149                                 continue;
6150 
6151                         /* Account for what is only usable for kernelcore */
6152                         if (start_pfn < usable_startpfn) {
6153                                 unsigned long kernel_pages;
6154                                 kernel_pages = min(end_pfn, usable_startpfn)
6155                                                                 - start_pfn;
6156 
6157                                 kernelcore_remaining -= min(kernel_pages,
6158                                                         kernelcore_remaining);
6159                                 required_kernelcore -= min(kernel_pages,
6160                                                         required_kernelcore);
6161 
6162                                 /* Continue if range is now fully accounted */
6163                                 if (end_pfn <= usable_startpfn) {
6164 
6165                                         /*
6166                                          * Push zone_movable_pfn to the end so
6167                                          * that if we have to rebalance
6168                                          * kernelcore across nodes, we will
6169                                          * not double account here
6170                                          */
6171                                         zone_movable_pfn[nid] = end_pfn;
6172                                         continue;
6173                                 }
6174                                 start_pfn = usable_startpfn;
6175                         }
6176 
6177                         /*
6178                          * The usable PFN range for ZONE_MOVABLE is from
6179                          * start_pfn->end_pfn. Calculate size_pages as the
6180                          * number of pages used as kernelcore
6181                          */
6182                         size_pages = end_pfn - start_pfn;
6183                         if (size_pages > kernelcore_remaining)
6184                                 size_pages = kernelcore_remaining;
6185                         zone_movable_pfn[nid] = start_pfn + size_pages;
6186 
6187                         /*
6188                          * Some kernelcore has been met, update counts and
6189                          * break if the kernelcore for this node has been
6190                          * satisfied
6191                          */
6192                         required_kernelcore -= min(required_kernelcore,
6193                                                                 size_pages);
6194                         kernelcore_remaining -= size_pages;
6195                         if (!kernelcore_remaining)
6196                                 break;
6197                 }
6198         }
6199 
6200         /*
6201          * If there is still required_kernelcore, we do another pass with one
6202          * less node in the count. This will push zone_movable_pfn[nid] further
6203          * along on the nodes that still have memory until kernelcore is
6204          * satisfied
6205          */
6206         usable_nodes--;
6207         if (usable_nodes && required_kernelcore > usable_nodes)
6208                 goto restart;
6209 
6210 out2:
6211         /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
6212         for (nid = 0; nid < MAX_NUMNODES; nid++)
6213                 zone_movable_pfn[nid] =
6214                         roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
6215 
6216 out:
6217         /* restore the node_state */
6218         node_states[N_MEMORY] = saved_node_state;
6219 }
6220 
6221 /* Any regular or high memory on that node ? */
6222 static void check_for_memory(pg_data_t *pgdat, int nid)
6223 {
6224         enum zone_type zone_type;
6225 
6226         if (N_MEMORY == N_NORMAL_MEMORY)
6227                 return;
6228 
6229         for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
6230                 struct zone *zone = &pgdat->node_zones[zone_type];
6231                 if (populated_zone(zone)) {
6232                         node_set_state(nid, N_HIGH_MEMORY);
6233                         if (N_NORMAL_MEMORY != N_HIGH_MEMORY &&
6234                             zone_type <= ZONE_NORMAL)
6235                                 node_set_state(nid, N_NORMAL_MEMORY);
6236                         break;
6237                 }
6238         }
6239 }
6240 
6241 /**
6242  * free_area_init_nodes - Initialise all pg_data_t and zone data
6243  * @max_zone_pfn: an array of max PFNs for each zone
6244  *
6245  * This will call free_area_init_node() for each active node in the system.
6246  * Using the page ranges provided by memblock_set_node(), the size of each
6247  * zone in each node and their holes is calculated. If the maximum PFN
6248  * between two adjacent zones match, it is assumed that the zone is empty.
6249  * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
6250  * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
6251  * starts where the previous one ended. For example, ZONE_DMA32 starts
6252  * at arch_max_dma_pfn.
6253  */
6254 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
6255 {
6256         unsigned long start_pfn, end_pfn;
6257         int i, nid;
6258 
6259         /* Record where the zone boundaries are */
6260         memset(arch_zone_lowest_possible_pfn, 0,
6261                                 sizeof(arch_zone_lowest_possible_pfn));
6262         memset(arch_zone_highest_possible_pfn, 0,
6263                                 sizeof(arch_zone_highest_possible_pfn));
6264 
6265         start_pfn = find_min_pfn_with_active_regions();
6266 
6267         for (i = 0; i < MAX_NR_ZONES; i++) {
6268                 if (i == ZONE_MOVABLE)
6269                         continue;
6270 
6271                 end_pfn = max(max_zone_pfn[i], start_pfn);
6272                 arch_zone_lowest_possible_pfn[i] = start_pfn;
6273                 arch_zone_highest_possible_pfn[i] = end_pfn;
6274 
6275                 start_pfn = end_pfn;
6276         }
6277         arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
6278         arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
6279 
6280         /* Find the PFNs that ZONE_MOVABLE begins at in each node */
6281         memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
6282         find_zone_movable_pfns_for_nodes();
6283 
6284         /* Print out the zone ranges */
6285         pr_info("Zone ranges:\n");
6286         for (i = 0; i < MAX_NR_ZONES; i++) {
6287                 if (i == ZONE_MOVABLE)
6288                         continue;
6289                 pr_info("  %-8s ", zone_names[i]);
6290                 if (arch_zone_lowest_possible_pfn[i] ==
6291                                 arch_zone_highest_possible_pfn[i])
6292                         pr_cont("empty\n");
6293                 else
6294                         pr_cont("[mem %#018Lx-%#018Lx]\n",
6295                                 (u64)arch_zone_lowest_possible_pfn[i]
6296                                         << PAGE_SHIFT,
6297                                 ((u64)arch_zone_highest_possible_pfn[i]
6298                                         << PAGE_SHIFT) - 1);
6299         }
6300 
6301         /* Print out the PFNs ZONE_MOVABLE begins at in each node */
6302         pr_info("Movable zone start for each node\n");
6303         for (i = 0; i < MAX_NUMNODES; i++) {
6304                 if (zone_movable_pfn[i])
6305                         pr_info("  Node %d: %#018Lx\n", i,
6306                                (u64)zone_movable_pfn[i] << PAGE_SHIFT);
6307         }
6308 
6309         /* Print out the early node map */
6310         pr_info("Early memory node ranges\n");
6311         for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
6312                 pr_info("  node %3d: [mem %#018Lx-%#018Lx]\n", nid,
6313                         (u64)start_pfn << PAGE_SHIFT,
6314                         ((u64)end_pfn << PAGE_SHIFT) - 1);
6315 
6316         /* Initialise every node */
6317         mminit_verify_pageflags_layout();
6318         setup_nr_node_ids();
6319         for_each_online_node(nid) {
6320                 pg_data_t *pgdat = NODE_DATA(nid);
6321                 free_area_init_node(nid, NULL,
6322                                 find_min_pfn_for_node(nid), NULL);
6323 
6324                 /* Any memory on that node */
6325                 if (pgdat->node_present_pages)
6326                         node_set_state(nid, N_MEMORY);
6327                 check_for_memory(pgdat, nid);
6328         }
6329 }
6330 
6331 static int __init cmdline_parse_core(char *p, unsigned long *core)
6332 {
6333         unsigned long long coremem;
6334         if (!p)
6335                 return -EINVAL;
6336 
6337         coremem = memparse(p, &p);
6338         *core = coremem >> PAGE_SHIFT;
6339 
6340         /* Paranoid check that UL is enough for the coremem value */
6341         WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
6342 
6343         return 0;
6344 }
6345 
6346 /*
6347  * kernelcore=size sets the amount of memory for use for allocations that
6348  * cannot be reclaimed or migrated.
6349  */
6350 static int __init cmdline_parse_kernelcore(char *p)
6351 {
6352         /* parse kernelcore=mirror */
6353         if (parse_option_str(p, "mirror")) {
6354                 mirrored_kernelcore = true;
6355                 return 0;
6356         }
6357 
6358         return cmdline_parse_core(p, &required_kernelcore);
6359 }
6360 
6361 /*
6362  * movablecore=size sets the amount of memory for use for allocations that
6363  * can be reclaimed or migrated.
6364  */
6365 static int __init cmdline_parse_movablecore(char *p)
6366 {
6367         return cmdline_parse_core(p, &required_movablecore);
6368 }
6369 
6370 early_param("kernelcore", cmdline_parse_kernelcore);
6371 early_param("movablecore", cmdline_parse_movablecore);
6372 
6373 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6374 
6375 void adjust_managed_page_count(struct page *page, long count)
6376 {
6377         spin_lock(&managed_page_count_lock);
6378         page_zone(page)->managed_pages += count;
6379         totalram_pages += count;
6380 #ifdef CONFIG_HIGHMEM
6381         if (PageHighMem(page))
6382                 totalhigh_pages += count;
6383 #endif
6384         spin_unlock(&managed_page_count_lock);
6385 }
6386 EXPORT_SYMBOL(adjust_managed_page_count);
6387 
6388 unsigned long free_reserved_area(void *start, void *end, int poison, char *s)
6389 {
6390         void *pos;
6391         unsigned long pages = 0;
6392 
6393         start = (void *)PAGE_ALIGN((unsigned long)start);
6394         end = (void *)((unsigned long)end & PAGE_MASK);
6395         for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
6396                 if ((unsigned int)poison <= 0xFF)
6397                         memset(pos, poison, PAGE_SIZE);
6398                 free_reserved_page(virt_to_page(pos));
6399         }
6400 
6401         if (pages && s)
6402                 pr_info("Freeing %s memory: %ldK (%p - %p)\n",
6403                         s, pages << (PAGE_SHIFT - 10), start, end);
6404 
6405         return pages;
6406 }
6407 EXPORT_SYMBOL(free_reserved_area);
6408 
6409 #ifdef  CONFIG_HIGHMEM
6410 void free_highmem_page(struct page *page)
6411 {
6412         __free_reserved_page(page);
6413         totalram_pages++;
6414         page_zone(page)->managed_pages++;
6415         totalhigh_pages++;
6416 }
6417 #endif
6418 
6419 
6420 void __init mem_init_print_info(const char *str)
6421 {
6422         unsigned long physpages, codesize, datasize, rosize, bss_size;
6423         unsigned long init_code_size, init_data_size;
6424 
6425         physpages = get_num_physpages();
6426         codesize = _etext - _stext;
6427         datasize = _edata - _sdata;
6428         rosize = __end_rodata - __start_rodata;
6429         bss_size = __bss_stop - __bss_start;
6430         init_data_size = __init_end - __init_begin;
6431         init_code_size = _einittext - _sinittext;
6432 
6433         /*
6434          * Detect special cases and adjust section sizes accordingly:
6435          * 1) .init.* may be embedded into .data sections
6436          * 2) .init.text.* may be out of [__init_begin, __init_end],
6437          *    please refer to arch/tile/kernel/vmlinux.lds.S.
6438          * 3) .rodata.* may be embedded into .text or .data sections.
6439          */
6440 #define adj_init_size(start, end, size, pos, adj) \
6441         do { \
6442                 if (start <= pos && pos < end && size > adj) \
6443                         size -= adj; \
6444         } while (0)
6445 
6446         adj_init_size(__init_begin, __init_end, init_data_size,
6447                      _sinittext, init_code_size);
6448         adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
6449         adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
6450         adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
6451         adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
6452 
6453 #undef  adj_init_size
6454 
6455         pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
6456 #ifdef  CONFIG_HIGHMEM
6457                 ", %luK highmem"
6458 #endif
6459                 "%s%s)\n",
6460                 nr_free_pages() << (PAGE_SHIFT - 10),
6461                 physpages << (PAGE_SHIFT - 10),
6462                 codesize >> 10, datasize >> 10, rosize >> 10,
6463                 (init_data_size + init_code_size) >> 10, bss_size >> 10,
6464                 (physpages - totalram_pages - totalcma_pages) << (PAGE_SHIFT - 10),
6465                 totalcma_pages << (PAGE_SHIFT - 10),
6466 #ifdef  CONFIG_HIGHMEM
6467                 totalhigh_pages << (PAGE_SHIFT - 10),
6468 #endif
6469                 str ? ", " : "", str ? str : "");
6470 }
6471 
6472 /**
6473  * set_dma_reserve - set the specified number of pages reserved in the first zone
6474  * @new_dma_reserve: The number of pages to mark reserved
6475  *
6476  * The per-cpu batchsize and zone watermarks are determined by managed_pages.
6477  * In the DMA zone, a significant percentage may be consumed by kernel image
6478  * and other unfreeable allocations which can skew the watermarks badly. This
6479  * function may optionally be used to account for unfreeable pages in the
6480  * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
6481  * smaller per-cpu batchsize.
6482  */
6483 void __init set_dma_reserve(unsigned long new_dma_reserve)
6484 {
6485         dma_reserve = new_dma_reserve;
6486 }
6487 
6488 void __init free_area_init(unsigned long *zones_size)
6489 {
6490         free_area_init_node(0, zones_size,
6491                         __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
6492 }
6493 
6494 static int page_alloc_cpu_notify(struct notifier_block *self,
6495                                  unsigned long action, void *hcpu)
6496 {
6497         int cpu = (unsigned long)hcpu;
6498 
6499         if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
6500                 lru_add_drain_cpu(cpu);
6501                 drain_pages(cpu);
6502 
6503                 /*
6504                  * Spill the event counters of the dead processor
6505                  * into the current processors event counters.
6506                  * This artificially elevates the count of the current
6507                  * processor.
6508                  */
6509                 vm_events_fold_cpu(cpu);
6510 
6511                 /*
6512                  * Zero the differential counters of the dead processor
6513                  * so that the vm statistics are consistent.
6514                  *
6515                  * This is only okay since the processor is dead and cannot
6516                  * race with what we are doing.
6517                  */
6518                 cpu_vm_stats_fold(cpu);
6519         }
6520         return NOTIFY_OK;
6521 }
6522 
6523 void __init page_alloc_init(void)
6524 {
6525         hotcpu_notifier(page_alloc_cpu_notify, 0);
6526 }
6527 
6528 /*
6529  * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio
6530  *      or min_free_kbytes changes.
6531  */
6532 static void calculate_totalreserve_pages(void)
6533 {
6534         struct pglist_data *pgdat;
6535         unsigned long reserve_pages = 0;
6536         enum zone_type i, j;
6537 
6538         for_each_online_pgdat(pgdat) {
6539 
6540                 pgdat->totalreserve_pages = 0;
6541 
6542                 for (i = 0; i < MAX_NR_ZONES; i++) {
6543                         struct zone *zone = pgdat->node_zones + i;
6544                         long max = 0;
6545 
6546                         /* Find valid and maximum lowmem_reserve in the zone */
6547                         for (j = i; j < MAX_NR_ZONES; j++) {
6548                                 if (zone->lowmem_reserve[j] > max)
6549                                         max = zone->lowmem_reserve[j];
6550                         }
6551 
6552                         /* we treat the high watermark as reserved pages. */
6553                         max += high_wmark_pages(zone);
6554 
6555                         if (max > zone->managed_pages)
6556                                 max = zone->managed_pages;
6557 
6558                         pgdat->totalreserve_pages += max;
6559 
6560                         reserve_pages += max;
6561                 }
6562         }
6563         totalreserve_pages = reserve_pages;
6564 }
6565 
6566 /*
6567  * setup_per_zone_lowmem_reserve - called whenever
6568  *      sysctl_lowmem_reserve_ratio changes.  Ensures that each zone
6569  *      has a correct pages reserved value, so an adequate number of
6570  *      pages are left in the zone after a successful __alloc_pages().
6571  */
6572 static void setup_per_zone_lowmem_reserve(void)
6573 {
6574         struct pglist_data *pgdat;
6575         enum zone_type j, idx;
6576 
6577         for_each_online_pgdat(pgdat) {
6578                 for (j = 0; j < MAX_NR_ZONES; j++) {
6579                         struct zone *zone = pgdat->node_zones + j;
6580                         unsigned long managed_pages = zone->managed_pages;
6581 
6582                         zone->lowmem_reserve[j] = 0;
6583 
6584                         idx = j;
6585                         while (idx) {
6586                                 struct zone *lower_zone;
6587 
6588                                 idx--;
6589 
6590                                 if (sysctl_lowmem_reserve_ratio[idx] < 1)
6591                                         sysctl_lowmem_reserve_ratio[idx] = 1;
6592 
6593                                 lower_zone = pgdat->node_zones + idx;
6594                                 lower_zone->lowmem_reserve[j] = managed_pages /
6595                                         sysctl_lowmem_reserve_ratio[idx];
6596                                 managed_pages += lower_zone->managed_pages;
6597                         }
6598                 }
6599         }
6600 
6601         /* update totalreserve_pages */
6602         calculate_totalreserve_pages();
6603 }
6604 
6605 static void __setup_per_zone_wmarks(void)
6606 {
6607         unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
6608         unsigned long lowmem_pages = 0;
6609         struct zone *zone;
6610         unsigned long flags;
6611 
6612         /* Calculate total number of !ZONE_HIGHMEM pages */
6613         for_each_zone(zone) {
6614                 if (!is_highmem(zone))
6615                         lowmem_pages += zone->managed_pages;
6616         }
6617 
6618         for_each_zone(zone) {
6619                 u64 tmp;
6620 
6621                 spin_lock_irqsave(&zone->lock, flags);
6622                 tmp = (u64)pages_min * zone->managed_pages;
6623                 do_div(tmp, lowmem_pages);
6624                 if (is_highmem(zone)) {
6625                         /*
6626                          * __GFP_HIGH and PF_MEMALLOC allocations usually don't
6627                          * need highmem pages, so cap pages_min to a small
6628                          * value here.
6629                          *
6630                          * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
6631                          * deltas control asynch page reclaim, and so should
6632                          * not be capped for highmem.
6633                          */
6634                         unsigned long min_pages;
6635 
6636                         min_pages = zone->managed_pages / 1024;
6637                         min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
6638                         zone->watermark[WMARK_MIN] = min_pages;
6639                 } else {
6640                         /*
6641                          * If it's a lowmem zone, reserve a number of pages
6642                          * proportionate to the zone's size.
6643                          */
6644                         zone->watermark[WMARK_MIN] = tmp;
6645                 }
6646 
6647                 /*
6648                  * Set the kswapd watermarks distance according to the
6649                  * scale factor in proportion to available memory, but
6650                  * ensure a minimum size on small systems.
6651                  */
6652                 tmp = max_t(u64, tmp >> 2,
6653                             mult_frac(zone->managed_pages,
6654                                       watermark_scale_factor, 10000));
6655 
6656                 zone->watermark[WMARK_LOW]  = min_wmark_pages(zone) + tmp;
6657                 zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;
6658 
6659                 spin_unlock_irqrestore(&zone->lock, flags);
6660         }
6661 
6662         /* update totalreserve_pages */
6663         calculate_totalreserve_pages();
6664 }
6665 
6666 /**
6667  * setup_per_zone_wmarks - called when min_free_kbytes changes
6668  * or when memory is hot-{added|removed}
6669  *
6670  * Ensures that the watermark[min,low,high] values for each zone are set
6671  * correctly with respect to min_free_kbytes.
6672  */
6673 void setup_per_zone_wmarks(void)
6674 {
6675         mutex_lock(&zonelists_mutex);
6676         __setup_per_zone_wmarks();
6677         mutex_unlock(&zonelists_mutex);
6678 }
6679 
6680 /*
6681  * Initialise min_free_kbytes.
6682  *
6683  * For small machines we want it small (128k min).  For large machines
6684  * we want it large (64MB max).  But it is not linear, because network
6685  * bandwidth does not increase linearly with machine size.  We use
6686  *
6687  *      min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
6688  *      min_free_kbytes = sqrt(lowmem_kbytes * 16)
6689  *
6690  * which yields
6691  *
6692  * 16MB:        512k
6693  * 32MB:        724k
6694  * 64MB:        1024k
6695  * 128MB:       1448k
6696  * 256MB:       2048k
6697  * 512MB:       2896k
6698  * 1024MB:      4096k
6699  * 2048MB:      5792k
6700  * 4096MB:      8192k
6701  * 8192MB:      11584k
6702  * 16384MB:     16384k
6703  */
6704 int __meminit init_per_zone_wmark_min(void)
6705 {
6706         unsigned long lowmem_kbytes;
6707         int new_min_free_kbytes;
6708 
6709         lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
6710         new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
6711 
6712         if (new_min_free_kbytes > user_min_free_kbytes) {
6713                 min_free_kbytes = new_min_free_kbytes;
6714                 if (min_free_kbytes < 128)
6715                         min_free_kbytes = 128;
6716                 if (min_free_kbytes > 65536)
6717                         min_free_kbytes = 65536;
6718         } else {
6719                 pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
6720                                 new_min_free_kbytes, user_min_free_kbytes);
6721         }
6722         setup_per_zone_wmarks();
6723         refresh_zone_stat_thresholds();
6724         setup_per_zone_lowmem_reserve();
6725 
6726 #ifdef CONFIG_NUMA
6727         setup_min_unmapped_ratio();
6728         setup_min_slab_ratio();
6729 #endif
6730 
6731         return 0;
6732 }
6733 core_initcall(init_per_zone_wmark_min)
6734 
6735 /*
6736  * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
6737  *      that we can call two helper functions whenever min_free_kbytes
6738  *      changes.
6739  */
6740 int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
6741         void __user *buffer, size_t *length, loff_t *ppos)
6742 {
6743         int rc;
6744 
6745         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6746         if (rc)
6747                 return rc;
6748 
6749         if (write) {
6750                 user_min_free_kbytes = min_free_kbytes;
6751                 setup_per_zone_wmarks();
6752         }
6753         return 0;
6754 }
6755 
6756 int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
6757         void __user *buffer, size_t *length, loff_t *ppos)
6758 {
6759         int rc;
6760 
6761         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6762         if (rc)
6763                 return rc;
6764 
6765         if (write)
6766                 setup_per_zone_wmarks();
6767 
6768         return 0;
6769 }
6770 
6771 #ifdef CONFIG_NUMA
6772 static void setup_min_unmapped_ratio(void)
6773 {
6774         pg_data_t *pgdat;
6775         struct zone *zone;
6776 
6777         for_each_online_pgdat(pgdat)
6778                 pgdat->min_unmapped_pages = 0;
6779 
6780         for_each_zone(zone)
6781                 zone->zone_pgdat->min_unmapped_pages += (zone->managed_pages *
6782                                 sysctl_min_unmapped_ratio) / 100;
6783 }
6784 
6785 
6786 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
6787         void __user *buffer, size_t *length, loff_t *ppos)
6788 {
6789         int rc;
6790 
6791         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6792         if (rc)
6793                 return rc;
6794 
6795         setup_min_unmapped_ratio();
6796 
6797         return 0;
6798 }
6799 
6800 static void setup_min_slab_ratio(void)
6801 {
6802         pg_data_t *pgdat;
6803         struct zone *zone;
6804 
6805         for_each_online_pgdat(pgdat)
6806                 pgdat->min_slab_pages = 0;
6807 
6808         for_each_zone(zone)
6809                 zone->zone_pgdat->min_slab_pages += (zone->managed_pages *
6810                                 sysctl_min_slab_ratio) / 100;
6811 }
6812 
6813 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
6814         void __user *buffer, size_t *length, loff_t *ppos)
6815 {
6816         int rc;
6817 
6818         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6819         if (rc)
6820                 return rc;
6821 
6822         setup_min_slab_ratio();
6823 
6824         return 0;
6825 }
6826 #endif
6827 
6828 /*
6829  * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
6830  *      proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
6831  *      whenever sysctl_lowmem_reserve_ratio changes.
6832  *
6833  * The reserve ratio obviously has absolutely no relation with the
6834  * minimum watermarks. The lowmem reserve ratio can only make sense
6835  * if in function of the boot time zone sizes.
6836  */
6837 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
6838         void __user *buffer, size_t *length, loff_t *ppos)
6839 {
6840         proc_dointvec_minmax(table, write, buffer, length, ppos);
6841         setup_per_zone_lowmem_reserve();
6842         return 0;
6843 }
6844 
6845 /*
6846  * percpu_pagelist_fraction - changes the pcp->high for each zone on each
6847  * cpu.  It is the fraction of total pages in each zone that a hot per cpu
6848  * pagelist can have before it gets flushed back to buddy allocator.
6849  */
6850 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write,
6851         void __user *buffer, size_t *length, loff_t *ppos)
6852 {
6853         struct zone *zone;
6854         int old_percpu_pagelist_fraction;
6855         int ret;
6856 
6857         mutex_lock(&pcp_batch_high_lock);
6858         old_percpu_pagelist_fraction = percpu_pagelist_fraction;
6859 
6860         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
6861         if (!write || ret < 0)
6862                 goto out;
6863 
6864         /* Sanity checking to avoid pcp imbalance */
6865         if (percpu_pagelist_fraction &&
6866             percpu_pagelist_fraction < MIN_PERCPU_PAGELIST_FRACTION) {
6867                 percpu_pagelist_fraction = old_percpu_pagelist_fraction;
6868                 ret = -EINVAL;
6869                 goto out;
6870         }
6871 
6872         /* No change? */
6873         if (percpu_pagelist_fraction == old_percpu_pagelist_fraction)
6874                 goto out;
6875 
6876         for_each_populated_zone(zone) {
6877                 unsigned int cpu;
6878 
6879                 for_each_possible_cpu(cpu)
6880                         pageset_set_high_and_batch(zone,
6881                                         per_cpu_ptr(zone->pageset, cpu));
6882         }
6883 out:
6884         mutex_unlock(&pcp_batch_high_lock);
6885         return ret;
6886 }
6887 
6888 #ifdef CONFIG_NUMA
6889 int hashdist = HASHDIST_DEFAULT;
6890 
6891 static int __init set_hashdist(char *str)
6892 {
6893         if (!str)
6894                 return 0;
6895         hashdist = simple_strtoul(str, &str, 0);
6896         return 1;
6897 }
6898 __setup("hashdist=", set_hashdist);
6899 #endif
6900 
6901 #ifndef __HAVE_ARCH_RESERVED_KERNEL_PAGES
6902 /*
6903  * Returns the number of pages that arch has reserved but
6904  * is not known to alloc_large_system_hash().
6905  */
6906 static unsigned long __init arch_reserved_kernel_pages(void)
6907 {
6908         return 0;
6909 }
6910 #endif
6911 
6912 /*
6913  * allocate a large system hash table from bootmem
6914  * - it is assumed that the hash table must contain an exact power-of-2
6915  *   quantity of entries
6916  * - limit is the number of hash buckets, not the total allocation size
6917  */
6918 void *__init alloc_large_system_hash(const char *tablename,
6919                                      unsigned long bucketsize,
6920                                      unsigned long numentries,
6921                                      int scale,
6922                                      int flags,
6923                                      unsigned int *_hash_shift,
6924                                      unsigned int *_hash_mask,
6925                                      unsigned long low_limit,
6926                                      unsigned long high_limit)
6927 {
6928         unsigned long long max = high_limit;
6929         unsigned long log2qty, size;
6930         void *table = NULL;
6931 
6932         /* allow the kernel cmdline to have a say */
6933         if (!numentries) {
6934                 /* round applicable memory size up to nearest megabyte */
6935                 numentries = nr_kernel_pages;
6936                 numentries -= arch_reserved_kernel_pages();
6937 
6938                 /* It isn't necessary when PAGE_SIZE >= 1MB */
6939                 if (PAGE_SHIFT < 20)
6940                         numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
6941 
6942                 /* limit to 1 bucket per 2^scale bytes of low memory */
6943                 if (scale > PAGE_SHIFT)
6944                         numentries >>= (scale - PAGE_SHIFT);
6945                 else
6946                         numentries <<= (PAGE_SHIFT - scale);
6947 
6948                 /* Make sure we've got at least a 0-order allocation.. */
6949                 if (unlikely(flags & HASH_SMALL)) {
6950                         /* Makes no sense without HASH_EARLY */
6951                         WARN_ON(!(flags & HASH_EARLY));
6952                         if (!(numentries >> *_hash_shift)) {
6953                                 numentries = 1UL << *_hash_shift;
6954                                 BUG_ON(!numentries);
6955                         }
6956                 } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
6957                         numentries = PAGE_SIZE / bucketsize;
6958         }
6959         numentries = roundup_pow_of_two(numentries);
6960 
6961         /* limit allocation size to 1/16 total memory by default */
6962         if (max == 0) {
6963                 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
6964                 do_div(max, bucketsize);
6965         }
6966         max = min(max, 0x80000000ULL);
6967 
6968         if (numentries < low_limit)
6969                 numentries = low_limit;
6970         if (numentries > max)
6971                 numentries = max;
6972 
6973         log2qty = ilog2(numentries);
6974 
6975         do {
6976                 size = bucketsize << log2qty;
6977                 if (flags & HASH_EARLY)
6978                         table = memblock_virt_alloc_nopanic(size, 0);
6979                 else if (hashdist)
6980                         table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
6981                 else {
6982                         /*
6983                          * If bucketsize is not a power-of-two, we may free
6984                          * some pages at the end of hash table which
6985                          * alloc_pages_exact() automatically does
6986                          */
6987                         if (get_order(size) < MAX_ORDER) {
6988                                 table = alloc_pages_exact(size, GFP_ATOMIC);
6989                                 kmemleak_alloc(table, size, 1, GFP_ATOMIC);
6990                         }
6991                 }
6992         } while (!table && size > PAGE_SIZE && --log2qty);
6993 
6994         if (!table)
6995                 panic("Failed to allocate %s hash table\n", tablename);
6996 
6997         pr_info("%s hash table entries: %ld (order: %d, %lu bytes)\n",
6998                 tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size);
6999 
7000         if (_hash_shift)
7001                 *_hash_shift = log2qty;
7002         if (_hash_mask)
7003                 *_hash_mask = (1 << log2qty) - 1;
7004 
7005         return table;
7006 }
7007 
7008 /*
7009  * This function checks whether pageblock includes unmovable pages or not.
7010  * If @count is not zero, it is okay to include less @count unmovable pages
7011  *
7012  * PageLRU check without isolation or lru_lock could race so that
7013  * MIGRATE_MOVABLE block might include unmovable pages. It means you can't
7014  * expect this function should be exact.
7015  */
7016 bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
7017                          bool skip_hwpoisoned_pages)
7018 {
7019         unsigned long pfn, iter, found;
7020         int mt;
7021 
7022         /*
7023          * For avoiding noise data, lru_add_drain_all() should be called
7024          * If ZONE_MOVABLE, the zone never contains unmovable pages
7025          */
7026         if (zone_idx(zone) == ZONE_MOVABLE)
7027                 return false;
7028         mt = get_pageblock_migratetype(page);
7029         if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
7030                 return false;
7031 
7032         pfn = page_to_pfn(page);
7033         for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
7034                 unsigned long check = pfn + iter;
7035 
7036                 if (!pfn_valid_within(check))
7037                         continue;
7038 
7039                 page = pfn_to_page(check);
7040 
7041                 /*
7042                  * Hugepages are not in LRU lists, but they're movable.
7043                  * We need not scan over tail pages bacause we don't
7044                  * handle each tail page individually in migration.
7045                  */
7046                 if (PageHuge(page)) {
7047                         iter = round_up(iter + 1, 1<<compound_order(page)) - 1;
7048                         continue;
7049                 }
7050 
7051                 /*
7052                  * We can't use page_count without pin a page
7053                  * because another CPU can free compound page.
7054                  * This check already skips compound tails of THP
7055                  * because their page->_refcount is zero at all time.
7056                  */
7057                 if (!page_ref_count(page)) {
7058                         if (PageBuddy(page))
7059                                 iter += (1 << page_order(page)) - 1;
7060                         continue;
7061                 }
7062 
7063                 /*
7064                  * The HWPoisoned page may be not in buddy system, and
7065                  * page_count() is not 0.
7066                  */
7067                 if (skip_hwpoisoned_pages && PageHWPoison(page))
7068                         continue;
7069 
7070                 if (!PageLRU(page))
7071                         found++;
7072                 /*
7073                  * If there are RECLAIMABLE pages, we need to check
7074                  * it.  But now, memory offline itself doesn't call
7075                  * shrink_node_slabs() and it still to be fixed.
7076                  */
7077                 /*
7078                  * If the page is not RAM, page_count()should be 0.
7079                  * we don't need more check. This is an _used_ not-movable page.
7080                  *
7081                  * The problematic thing here is PG_reserved pages. PG_reserved
7082                  * is set to both of a memory hole page and a _used_ kernel
7083                  * page at boot.
7084                  */
7085                 if (found > count)
7086                         return true;
7087         }
7088         return false;
7089 }
7090 
7091 bool is_pageblock_removable_nolock(struct page *page)
7092 {
7093         struct zone *zone;
7094         unsigned long pfn;
7095 
7096         /*
7097          * We have to be careful here because we are iterating over memory
7098          * sections which are not zone aware so we might end up outside of
7099          * the zone but still within the section.
7100          * We have to take care about the node as well. If the node is offline
7101          * its NODE_DATA will be NULL - see page_zone.
7102          */
7103         if (!node_online(page_to_nid(page)))
7104                 return false;
7105 
7106         zone = page_zone(page);
7107         pfn = page_to_pfn(page);
7108         if (!zone_spans_pfn(zone, pfn))
7109                 return false;
7110 
7111         return !has_unmovable_pages(zone, page, 0, true);
7112 }
7113 
7114 #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA)
7115 
7116 static unsigned long pfn_max_align_down(unsigned long pfn)
7117 {
7118         return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
7119                              pageblock_nr_pages) - 1);
7120 }
7121 
7122 static unsigned long pfn_max_align_up(unsigned long pfn)
7123 {
7124         return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
7125                                 pageblock_nr_pages));
7126 }
7127 
7128 /* [start, end) must belong to a single zone. */
7129 static int __alloc_contig_migrate_range(struct compact_control *cc,
7130                                         unsigned long start, unsigned long end)
7131 {
7132         /* This function is based on compact_zone() from compaction.c. */
7133         unsigned long nr_reclaimed;
7134         unsigned long pfn = start;
7135         unsigned int tries = 0;
7136         int ret = 0;
7137 
7138         migrate_prep();
7139 
7140         while (pfn < end || !list_empty(&cc->migratepages)) {
7141                 if (fatal_signal_pending(current)) {
7142                         ret = -EINTR;
7143                         break;
7144                 }
7145 
7146                 if (list_empty(&cc->migratepages)) {
7147                         cc->nr_migratepages = 0;
7148                         pfn = isolate_migratepages_range(cc, pfn, end);
7149                         if (!pfn) {
7150                                 ret = -EINTR;
7151                                 break;
7152                         }
7153                         tries = 0;
7154                 } else if (++tries == 5) {
7155                         ret = ret < 0 ? ret : -EBUSY;
7156                         break;
7157                 }
7158 
7159                 nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
7160                                                         &cc->migratepages);
7161                 cc->nr_migratepages -= nr_reclaimed;
7162 
7163                 ret = migrate_pages(&cc->migratepages, alloc_migrate_target,
7164                                     NULL, 0, cc->mode, MR_CMA);
7165         }
7166         if (ret < 0) {
7167                 putback_movable_pages(&cc->migratepages);
7168                 return ret;
7169         }
7170         return 0;
7171 }
7172 
7173 /**
7174  * alloc_contig_range() -- tries to allocate given range of pages
7175  * @start:      start PFN to allocate
7176  * @end:        one-past-the-last PFN to allocate
7177  * @migratetype:        migratetype of the underlaying pageblocks (either
7178  *                      #MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
7179  *                      in range must have the same migratetype and it must
7180  *                      be either of the two.
7181  *
7182  * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
7183  * aligned, however it's the caller's responsibility to guarantee that
7184  * we are the only thread that changes migrate type of pageblocks the
7185  * pages fall in.
7186  *
7187  * The PFN range must belong to a single zone.
7188  *
7189  * Returns zero on success or negative error code.  On success all
7190  * pages which PFN is in [start, end) are allocated for the caller and
7191  * need to be freed with free_contig_range().
7192  */
7193 int alloc_contig_range(unsigned long start, unsigned long end,
7194                        unsigned migratetype)
7195 {
7196         unsigned long outer_start, outer_end;
7197         unsigned int order;
7198         int ret = 0;
7199 
7200         struct compact_control cc = {
7201                 .nr_migratepages = 0,
7202                 .order = -1,
7203                 .zone = page_zone(pfn_to_page(start)),
7204                 .mode = MIGRATE_SYNC,
7205                 .ignore_skip_hint = true,
7206         };
7207         INIT_LIST_HEAD(&cc.migratepages);
7208 
7209         /*
7210          * What we do here is we mark all pageblocks in range as
7211          * MIGRATE_ISOLATE.  Because pageblock and max order pages may
7212          * have different sizes, and due to the way page allocator
7213          * work, we align the range to biggest of the two pages so
7214          * that page allocator won't try to merge buddies from
7215          * different pageblocks and change MIGRATE_ISOLATE to some
7216          * other migration type.
7217          *
7218          * Once the pageblocks are marked as MIGRATE_ISOLATE, we
7219          * migrate the pages from an unaligned range (ie. pages that
7220          * we are interested in).  This will put all the pages in
7221          * range back to page allocator as MIGRATE_ISOLATE.
7222          *
7223          * When this is done, we take the pages in range from page
7224          * allocator removing them from the buddy system.  This way
7225          * page allocator will never consider using them.
7226          *
7227          * This lets us mark the pageblocks back as
7228          * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
7229          * aligned range but not in the unaligned, original range are
7230          * put back to page allocator so that buddy can use them.
7231          */
7232 
7233         ret = start_isolate_page_range(pfn_max_align_down(start),
7234                                        pfn_max_align_up(end), migratetype,
7235                                        false);
7236         if (ret)
7237                 return ret;
7238 
7239         /*
7240          * In case of -EBUSY, we'd like to know which page causes problem.
7241          * So, just fall through. We will check it in test_pages_isolated().
7242          */
7243         ret = __alloc_contig_migrate_range(&cc, start, end);
7244         if (ret && ret != -EBUSY)
7245                 goto done;
7246 
7247         /*
7248          * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
7249          * aligned blocks that are marked as MIGRATE_ISOLATE.  What's
7250          * more, all pages in [start, end) are free in page allocator.
7251          * What we are going to do is to allocate all pages from
7252          * [start, end) (that is remove them from page allocator).
7253          *
7254          * The only problem is that pages at the beginning and at the
7255          * end of interesting range may be not aligned with pages that
7256          * page allocator holds, ie. they can be part of higher order
7257          * pages.  Because of this, we reserve the bigger range and
7258          * once this is done free the pages we are not interested in.
7259          *
7260          * We don't have to hold zone->lock here because the pages are
7261          * isolated thus they won't get removed from buddy.
7262          */
7263 
7264         lru_add_drain_all();
7265         drain_all_pages(cc.zone);
7266 
7267         order = 0;
7268         outer_start = start;
7269         while (!PageBuddy(pfn_to_page(outer_start))) {
7270                 if (++order >= MAX_ORDER) {
7271                         outer_start = start;
7272                         break;
7273                 }
7274                 outer_start &= ~0UL << order;
7275         }
7276 
7277         if (outer_start != start) {
7278                 order = page_order(pfn_to_page(outer_start));
7279 
7280                 /*
7281                  * outer_start page could be small order buddy page and
7282                  * it doesn't include start page. Adjust outer_start
7283                  * in this case to report failed page properly
7284                  * on tracepoint in test_pages_isolated()
7285                  */
7286                 if (outer_start + (1UL << order) <= start)
7287                         outer_start = start;
7288         }
7289 
7290         /* Make sure the range is really isolated. */
7291         if (test_pages_isolated(outer_start, end, false)) {
7292                 pr_info("%s: [%lx, %lx) PFNs busy\n",
7293                         __func__, outer_start, end);
7294                 ret = -EBUSY;
7295                 goto done;
7296         }
7297 
7298         /* Grab isolated pages from freelists. */
7299         outer_end = isolate_freepages_range(&cc, outer_start, end);
7300         if (!outer_end) {
7301                 ret = -EBUSY;
7302                 goto done;
7303         }
7304 
7305         /* Free head and tail (if any) */
7306         if (start != outer_start)
7307                 free_contig_range(outer_start, start - outer_start);
7308         if (end != outer_end)
7309                 free_contig_range(end, outer_end - end);
7310 
7311 done:
7312         undo_isolate_page_range(pfn_max_align_down(start),
7313                                 pfn_max_align_up(end), migratetype);
7314         return ret;
7315 }
7316 
7317 void free_contig_range(unsigned long pfn, unsigned nr_pages)
7318 {
7319         unsigned int count = 0;
7320 
7321         for (; nr_pages--; pfn++) {
7322                 struct page *page = pfn_to_page(pfn);
7323 
7324                 count += page_count(page) != 1;
7325                 __free_page(page);
7326         }
7327         WARN(count != 0, "%d pages are still in use!\n", count);
7328 }
7329 #endif
7330 
7331 #ifdef CONFIG_MEMORY_HOTPLUG
7332 /*
7333  * The zone indicated has a new number of managed_pages; batch sizes and percpu
7334  * page high values need to be recalulated.
7335  */
7336 void __meminit zone_pcp_update(struct zone *zone)
7337 {
7338         unsigned cpu;
7339         mutex_lock(&pcp_batch_high_lock);
7340         for_each_possible_cpu(cpu)
7341                 pageset_set_high_and_batch(zone,
7342                                 per_cpu_ptr(zone->pageset, cpu));
7343         mutex_unlock(&pcp_batch_high_lock);
7344 }
7345 #endif
7346 
7347 void zone_pcp_reset(struct zone *zone)
7348 {
7349         unsigned long flags;
7350         int cpu;
7351         struct per_cpu_pageset *pset;
7352 
7353         /* avoid races with drain_pages()  */
7354         local_irq_save(flags);
7355         if (zone->pageset != &boot_pageset) {
7356                 for_each_online_cpu(cpu) {
7357                         pset = per_cpu_ptr(zone->pageset, cpu);
7358                         drain_zonestat(zone, pset);
7359                 }
7360                 free_percpu(zone->pageset);
7361                 zone->pageset = &boot_pageset;
7362         }
7363         local_irq_restore(flags);
7364 }
7365 
7366 #ifdef CONFIG_MEMORY_HOTREMOVE
7367 /*
7368  * All pages in the range must be in a single zone and isolated
7369  * before calling this.
7370  */
7371 void
7372 __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
7373 {
7374         struct page *page;
7375         struct zone *zone;
7376         unsigned int order, i;
7377         unsigned long pfn;
7378         unsigned long flags;
7379         /* find the first valid pfn */
7380         for (pfn = start_pfn; pfn < end_pfn; pfn++)
7381                 if (pfn_valid(pfn))
7382                         break;
7383         if (pfn == end_pfn)
7384                 return;
7385         zone = page_zone(pfn_to_page(pfn));
7386         spin_lock_irqsave(&zone->lock, flags);
7387         pfn = start_pfn;
7388         while (pfn < end_pfn) {
7389                 if (!pfn_valid(pfn)) {
7390                         pfn++;
7391                         continue;
7392                 }
7393                 page = pfn_to_page(pfn);
7394                 /*
7395                  * The HWPoisoned page may be not in buddy system, and
7396                  * page_count() is not 0.
7397                  */
7398                 if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
7399                         pfn++;
7400                         SetPageReserved(page);
7401                         continue;
7402                 }
7403 
7404                 BUG_ON(page_count(page));
7405                 BUG_ON(!PageBuddy(page));
7406                 order = page_order(page);
7407 #ifdef CONFIG_DEBUG_VM
7408                 pr_info("remove from free list %lx %d %lx\n",
7409                         pfn, 1 << order, end_pfn);
7410 #endif
7411                 list_del(&page->lru);
7412                 rmv_page_order(page);
7413                 zone->free_area[order].nr_free--;
7414                 for (i = 0; i < (1 << order); i++)
7415                         SetPageReserved((page+i));
7416                 pfn += (1 << order);
7417         }
7418         spin_unlock_irqrestore(&zone->lock, flags);
7419 }
7420 #endif
7421 
7422 bool is_free_buddy_page(struct page *page)
7423 {
7424         struct zone *zone = page_zone(page);
7425         unsigned long pfn = page_to_pfn(page);
7426         unsigned long flags;
7427         unsigned int order;
7428 
7429         spin_lock_irqsave(&zone->lock, flags);
7430         for (order = 0; order < MAX_ORDER; order++) {
7431                 struct page *page_head = page - (pfn & ((1 << order) - 1));
7432 
7433                 if (PageBuddy(page_head) && page_order(page_head) >= order)
7434                         break;
7435         }
7436         spin_unlock_irqrestore(&zone->lock, flags);
7437 
7438         return order < MAX_ORDER;
7439 }
7440 

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