Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

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                 if (!pfn_valid_within(page_to_pfn(page))) {
1868                         page++;
1869                         continue;
1870                 }
1871 
1872                 /* Make sure we are not inadvertently changing nodes */
1873                 VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
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  * If @force is true, try to unreserve a pageblock even though highatomic
2063  * pageblock is exhausted.
2064  */
2065 static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
2066                                                 bool force)
2067 {
2068         struct zonelist *zonelist = ac->zonelist;
2069         unsigned long flags;
2070         struct zoneref *z;
2071         struct zone *zone;
2072         struct page *page;
2073         int order;
2074         bool ret;
2075 
2076         for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->high_zoneidx,
2077                                                                 ac->nodemask) {
2078                 /*
2079                  * Preserve at least one pageblock unless memory pressure
2080                  * is really high.
2081                  */
2082                 if (!force && zone->nr_reserved_highatomic <=
2083                                         pageblock_nr_pages)
2084                         continue;
2085 
2086                 spin_lock_irqsave(&zone->lock, flags);
2087                 for (order = 0; order < MAX_ORDER; order++) {
2088                         struct free_area *area = &(zone->free_area[order]);
2089 
2090                         page = list_first_entry_or_null(
2091                                         &area->free_list[MIGRATE_HIGHATOMIC],
2092                                         struct page, lru);
2093                         if (!page)
2094                                 continue;
2095 
2096                         /*
2097                          * In page freeing path, migratetype change is racy so
2098                          * we can counter several free pages in a pageblock
2099                          * in this loop althoug we changed the pageblock type
2100                          * from highatomic to ac->migratetype. So we should
2101                          * adjust the count once.
2102                          */
2103                         if (get_pageblock_migratetype(page) ==
2104                                                         MIGRATE_HIGHATOMIC) {
2105                                 /*
2106                                  * It should never happen but changes to
2107                                  * locking could inadvertently allow a per-cpu
2108                                  * drain to add pages to MIGRATE_HIGHATOMIC
2109                                  * while unreserving so be safe and watch for
2110                                  * underflows.
2111                                  */
2112                                 zone->nr_reserved_highatomic -= min(
2113                                                 pageblock_nr_pages,
2114                                                 zone->nr_reserved_highatomic);
2115                         }
2116 
2117                         /*
2118                          * Convert to ac->migratetype and avoid the normal
2119                          * pageblock stealing heuristics. Minimally, the caller
2120                          * is doing the work and needs the pages. More
2121                          * importantly, if the block was always converted to
2122                          * MIGRATE_UNMOVABLE or another type then the number
2123                          * of pageblocks that cannot be completely freed
2124                          * may increase.
2125                          */
2126                         set_pageblock_migratetype(page, ac->migratetype);
2127                         ret = move_freepages_block(zone, page, ac->migratetype);
2128                         if (ret) {
2129                                 spin_unlock_irqrestore(&zone->lock, flags);
2130                                 return ret;
2131                         }
2132                 }
2133                 spin_unlock_irqrestore(&zone->lock, flags);
2134         }
2135 
2136         return false;
2137 }
2138 
2139 /* Remove an element from the buddy allocator from the fallback list */
2140 static inline struct page *
2141 __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype)
2142 {
2143         struct free_area *area;
2144         unsigned int current_order;
2145         struct page *page;
2146         int fallback_mt;
2147         bool can_steal;
2148 
2149         /* Find the largest possible block of pages in the other list */
2150         for (current_order = MAX_ORDER-1;
2151                                 current_order >= order && current_order <= MAX_ORDER-1;
2152                                 --current_order) {
2153                 area = &(zone->free_area[current_order]);
2154                 fallback_mt = find_suitable_fallback(area, current_order,
2155                                 start_migratetype, false, &can_steal);
2156                 if (fallback_mt == -1)
2157                         continue;
2158 
2159                 page = list_first_entry(&area->free_list[fallback_mt],
2160                                                 struct page, lru);
2161                 if (can_steal &&
2162                         get_pageblock_migratetype(page) != MIGRATE_HIGHATOMIC)
2163                         steal_suitable_fallback(zone, page, start_migratetype);
2164 
2165                 /* Remove the page from the freelists */
2166                 area->nr_free--;
2167                 list_del(&page->lru);
2168                 rmv_page_order(page);
2169 
2170                 expand(zone, page, order, current_order, area,
2171                                         start_migratetype);
2172                 /*
2173                  * The pcppage_migratetype may differ from pageblock's
2174                  * migratetype depending on the decisions in
2175                  * find_suitable_fallback(). This is OK as long as it does not
2176                  * differ for MIGRATE_CMA pageblocks. Those can be used as
2177                  * fallback only via special __rmqueue_cma_fallback() function
2178                  */
2179                 set_pcppage_migratetype(page, start_migratetype);
2180 
2181                 trace_mm_page_alloc_extfrag(page, order, current_order,
2182                         start_migratetype, fallback_mt);
2183 
2184                 return page;
2185         }
2186 
2187         return NULL;
2188 }
2189 
2190 /*
2191  * Do the hard work of removing an element from the buddy allocator.
2192  * Call me with the zone->lock already held.
2193  */
2194 static struct page *__rmqueue(struct zone *zone, unsigned int order,
2195                                 int migratetype)
2196 {
2197         struct page *page;
2198 
2199         page = __rmqueue_smallest(zone, order, migratetype);
2200         if (unlikely(!page)) {
2201                 if (migratetype == MIGRATE_MOVABLE)
2202                         page = __rmqueue_cma_fallback(zone, order);
2203 
2204                 if (!page)
2205                         page = __rmqueue_fallback(zone, order, migratetype);
2206         }
2207 
2208         trace_mm_page_alloc_zone_locked(page, order, migratetype);
2209         return page;
2210 }
2211 
2212 /*
2213  * Obtain a specified number of elements from the buddy allocator, all under
2214  * a single hold of the lock, for efficiency.  Add them to the supplied list.
2215  * Returns the number of new pages which were placed at *list.
2216  */
2217 static int rmqueue_bulk(struct zone *zone, unsigned int order,
2218                         unsigned long count, struct list_head *list,
2219                         int migratetype, bool cold)
2220 {
2221         int i, alloced = 0;
2222 
2223         spin_lock(&zone->lock);
2224         for (i = 0; i < count; ++i) {
2225                 struct page *page = __rmqueue(zone, order, migratetype);
2226                 if (unlikely(page == NULL))
2227                         break;
2228 
2229                 if (unlikely(check_pcp_refill(page)))
2230                         continue;
2231 
2232                 /*
2233                  * Split buddy pages returned by expand() are received here
2234                  * in physical page order. The page is added to the callers and
2235                  * list and the list head then moves forward. From the callers
2236                  * perspective, the linked list is ordered by page number in
2237                  * some conditions. This is useful for IO devices that can
2238                  * merge IO requests if the physical pages are ordered
2239                  * properly.
2240                  */
2241                 if (likely(!cold))
2242                         list_add(&page->lru, list);
2243                 else
2244                         list_add_tail(&page->lru, list);
2245                 list = &page->lru;
2246                 alloced++;
2247                 if (is_migrate_cma(get_pcppage_migratetype(page)))
2248                         __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
2249                                               -(1 << order));
2250         }
2251 
2252         /*
2253          * i pages were removed from the buddy list even if some leak due
2254          * to check_pcp_refill failing so adjust NR_FREE_PAGES based
2255          * on i. Do not confuse with 'alloced' which is the number of
2256          * pages added to the pcp list.
2257          */
2258         __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
2259         spin_unlock(&zone->lock);
2260         return alloced;
2261 }
2262 
2263 #ifdef CONFIG_NUMA
2264 /*
2265  * Called from the vmstat counter updater to drain pagesets of this
2266  * currently executing processor on remote nodes after they have
2267  * expired.
2268  *
2269  * Note that this function must be called with the thread pinned to
2270  * a single processor.
2271  */
2272 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
2273 {
2274         unsigned long flags;
2275         int to_drain, batch;
2276 
2277         local_irq_save(flags);
2278         batch = READ_ONCE(pcp->batch);
2279         to_drain = min(pcp->count, batch);
2280         if (to_drain > 0) {
2281                 free_pcppages_bulk(zone, to_drain, pcp);
2282                 pcp->count -= to_drain;
2283         }
2284         local_irq_restore(flags);
2285 }
2286 #endif
2287 
2288 /*
2289  * Drain pcplists of the indicated processor and zone.
2290  *
2291  * The processor must either be the current processor and the
2292  * thread pinned to the current processor or a processor that
2293  * is not online.
2294  */
2295 static void drain_pages_zone(unsigned int cpu, struct zone *zone)
2296 {
2297         unsigned long flags;
2298         struct per_cpu_pageset *pset;
2299         struct per_cpu_pages *pcp;
2300 
2301         local_irq_save(flags);
2302         pset = per_cpu_ptr(zone->pageset, cpu);
2303 
2304         pcp = &pset->pcp;
2305         if (pcp->count) {
2306                 free_pcppages_bulk(zone, pcp->count, pcp);
2307                 pcp->count = 0;
2308         }
2309         local_irq_restore(flags);
2310 }
2311 
2312 /*
2313  * Drain pcplists of all zones on the indicated processor.
2314  *
2315  * The processor must either be the current processor and the
2316  * thread pinned to the current processor or a processor that
2317  * is not online.
2318  */
2319 static void drain_pages(unsigned int cpu)
2320 {
2321         struct zone *zone;
2322 
2323         for_each_populated_zone(zone) {
2324                 drain_pages_zone(cpu, zone);
2325         }
2326 }
2327 
2328 /*
2329  * Spill all of this CPU's per-cpu pages back into the buddy allocator.
2330  *
2331  * The CPU has to be pinned. When zone parameter is non-NULL, spill just
2332  * the single zone's pages.
2333  */
2334 void drain_local_pages(struct zone *zone)
2335 {
2336         int cpu = smp_processor_id();
2337 
2338         if (zone)
2339                 drain_pages_zone(cpu, zone);
2340         else
2341                 drain_pages(cpu);
2342 }
2343 
2344 /*
2345  * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
2346  *
2347  * When zone parameter is non-NULL, spill just the single zone's pages.
2348  *
2349  * Note that this code is protected against sending an IPI to an offline
2350  * CPU but does not guarantee sending an IPI to newly hotplugged CPUs:
2351  * on_each_cpu_mask() blocks hotplug and won't talk to offlined CPUs but
2352  * nothing keeps CPUs from showing up after we populated the cpumask and
2353  * before the call to on_each_cpu_mask().
2354  */
2355 void drain_all_pages(struct zone *zone)
2356 {
2357         int cpu;
2358 
2359         /*
2360          * Allocate in the BSS so we wont require allocation in
2361          * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
2362          */
2363         static cpumask_t cpus_with_pcps;
2364 
2365         /*
2366          * We don't care about racing with CPU hotplug event
2367          * as offline notification will cause the notified
2368          * cpu to drain that CPU pcps and on_each_cpu_mask
2369          * disables preemption as part of its processing
2370          */
2371         for_each_online_cpu(cpu) {
2372                 struct per_cpu_pageset *pcp;
2373                 struct zone *z;
2374                 bool has_pcps = false;
2375 
2376                 if (zone) {
2377                         pcp = per_cpu_ptr(zone->pageset, cpu);
2378                         if (pcp->pcp.count)
2379                                 has_pcps = true;
2380                 } else {
2381                         for_each_populated_zone(z) {
2382                                 pcp = per_cpu_ptr(z->pageset, cpu);
2383                                 if (pcp->pcp.count) {
2384                                         has_pcps = true;
2385                                         break;
2386                                 }
2387                         }
2388                 }
2389 
2390                 if (has_pcps)
2391                         cpumask_set_cpu(cpu, &cpus_with_pcps);
2392                 else
2393                         cpumask_clear_cpu(cpu, &cpus_with_pcps);
2394         }
2395         on_each_cpu_mask(&cpus_with_pcps, (smp_call_func_t) drain_local_pages,
2396                                                                 zone, 1);
2397 }
2398 
2399 #ifdef CONFIG_HIBERNATION
2400 
2401 void mark_free_pages(struct zone *zone)
2402 {
2403         unsigned long pfn, max_zone_pfn;
2404         unsigned long flags;
2405         unsigned int order, t;
2406         struct page *page;
2407 
2408         if (zone_is_empty(zone))
2409                 return;
2410 
2411         spin_lock_irqsave(&zone->lock, flags);
2412 
2413         max_zone_pfn = zone_end_pfn(zone);
2414         for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
2415                 if (pfn_valid(pfn)) {
2416                         page = pfn_to_page(pfn);
2417 
2418                         if (page_zone(page) != zone)
2419                                 continue;
2420 
2421                         if (!swsusp_page_is_forbidden(page))
2422                                 swsusp_unset_page_free(page);
2423                 }
2424 
2425         for_each_migratetype_order(order, t) {
2426                 list_for_each_entry(page,
2427                                 &zone->free_area[order].free_list[t], lru) {
2428                         unsigned long i;
2429 
2430                         pfn = page_to_pfn(page);
2431                         for (i = 0; i < (1UL << order); i++)
2432                                 swsusp_set_page_free(pfn_to_page(pfn + i));
2433                 }
2434         }
2435         spin_unlock_irqrestore(&zone->lock, flags);
2436 }
2437 #endif /* CONFIG_PM */
2438 
2439 /*
2440  * Free a 0-order page
2441  * cold == true ? free a cold page : free a hot page
2442  */
2443 void free_hot_cold_page(struct page *page, bool cold)
2444 {
2445         struct zone *zone = page_zone(page);
2446         struct per_cpu_pages *pcp;
2447         unsigned long flags;
2448         unsigned long pfn = page_to_pfn(page);
2449         int migratetype;
2450 
2451         if (!free_pcp_prepare(page))
2452                 return;
2453 
2454         migratetype = get_pfnblock_migratetype(page, pfn);
2455         set_pcppage_migratetype(page, migratetype);
2456         local_irq_save(flags);
2457         __count_vm_event(PGFREE);
2458 
2459         /*
2460          * We only track unmovable, reclaimable and movable on pcp lists.
2461          * Free ISOLATE pages back to the allocator because they are being
2462          * offlined but treat RESERVE as movable pages so we can get those
2463          * areas back if necessary. Otherwise, we may have to free
2464          * excessively into the page allocator
2465          */
2466         if (migratetype >= MIGRATE_PCPTYPES) {
2467                 if (unlikely(is_migrate_isolate(migratetype))) {
2468                         free_one_page(zone, page, pfn, 0, migratetype);
2469                         goto out;
2470                 }
2471                 migratetype = MIGRATE_MOVABLE;
2472         }
2473 
2474         pcp = &this_cpu_ptr(zone->pageset)->pcp;
2475         if (!cold)
2476                 list_add(&page->lru, &pcp->lists[migratetype]);
2477         else
2478                 list_add_tail(&page->lru, &pcp->lists[migratetype]);
2479         pcp->count++;
2480         if (pcp->count >= pcp->high) {
2481                 unsigned long batch = READ_ONCE(pcp->batch);
2482                 free_pcppages_bulk(zone, batch, pcp);
2483                 pcp->count -= batch;
2484         }
2485 
2486 out:
2487         local_irq_restore(flags);
2488 }
2489 
2490 /*
2491  * Free a list of 0-order pages
2492  */
2493 void free_hot_cold_page_list(struct list_head *list, bool cold)
2494 {
2495         struct page *page, *next;
2496 
2497         list_for_each_entry_safe(page, next, list, lru) {
2498                 trace_mm_page_free_batched(page, cold);
2499                 free_hot_cold_page(page, cold);
2500         }
2501 }
2502 
2503 /*
2504  * split_page takes a non-compound higher-order page, and splits it into
2505  * n (1<<order) sub-pages: page[0..n]
2506  * Each sub-page must be freed individually.
2507  *
2508  * Note: this is probably too low level an operation for use in drivers.
2509  * Please consult with lkml before using this in your driver.
2510  */
2511 void split_page(struct page *page, unsigned int order)
2512 {
2513         int i;
2514 
2515         VM_BUG_ON_PAGE(PageCompound(page), page);
2516         VM_BUG_ON_PAGE(!page_count(page), page);
2517 
2518 #ifdef CONFIG_KMEMCHECK
2519         /*
2520          * Split shadow pages too, because free(page[0]) would
2521          * otherwise free the whole shadow.
2522          */
2523         if (kmemcheck_page_is_tracked(page))
2524                 split_page(virt_to_page(page[0].shadow), order);
2525 #endif
2526 
2527         for (i = 1; i < (1 << order); i++)
2528                 set_page_refcounted(page + i);
2529         split_page_owner(page, order);
2530 }
2531 EXPORT_SYMBOL_GPL(split_page);
2532 
2533 int __isolate_free_page(struct page *page, unsigned int order)
2534 {
2535         unsigned long watermark;
2536         struct zone *zone;
2537         int mt;
2538 
2539         BUG_ON(!PageBuddy(page));
2540 
2541         zone = page_zone(page);
2542         mt = get_pageblock_migratetype(page);
2543 
2544         if (!is_migrate_isolate(mt)) {
2545                 /*
2546                  * Obey watermarks as if the page was being allocated. We can
2547                  * emulate a high-order watermark check with a raised order-0
2548                  * watermark, because we already know our high-order page
2549                  * exists.
2550                  */
2551                 watermark = min_wmark_pages(zone) + (1UL << order);
2552                 if (!zone_watermark_ok(zone, 0, watermark, 0, ALLOC_CMA))
2553                         return 0;
2554 
2555                 __mod_zone_freepage_state(zone, -(1UL << order), mt);
2556         }
2557 
2558         /* Remove page from free list */
2559         list_del(&page->lru);
2560         zone->free_area[order].nr_free--;
2561         rmv_page_order(page);
2562 
2563         /*
2564          * Set the pageblock if the isolated page is at least half of a
2565          * pageblock
2566          */
2567         if (order >= pageblock_order - 1) {
2568                 struct page *endpage = page + (1 << order) - 1;
2569                 for (; page < endpage; page += pageblock_nr_pages) {
2570                         int mt = get_pageblock_migratetype(page);
2571                         if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
2572                                 && mt != MIGRATE_HIGHATOMIC)
2573                                 set_pageblock_migratetype(page,
2574                                                           MIGRATE_MOVABLE);
2575                 }
2576         }
2577 
2578 
2579         return 1UL << order;
2580 }
2581 
2582 /*
2583  * Update NUMA hit/miss statistics
2584  *
2585  * Must be called with interrupts disabled.
2586  */
2587 static inline void zone_statistics(struct zone *preferred_zone, struct zone *z)
2588 {
2589 #ifdef CONFIG_NUMA
2590         enum zone_stat_item local_stat = NUMA_LOCAL;
2591 
2592         if (z->node != numa_node_id())
2593                 local_stat = NUMA_OTHER;
2594 
2595         if (z->node == preferred_zone->node)
2596                 __inc_zone_state(z, NUMA_HIT);
2597         else {
2598                 __inc_zone_state(z, NUMA_MISS);
2599                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
2600         }
2601         __inc_zone_state(z, local_stat);
2602 #endif
2603 }
2604 
2605 /*
2606  * Allocate a page from the given zone. Use pcplists for order-0 allocations.
2607  */
2608 static inline
2609 struct page *buffered_rmqueue(struct zone *preferred_zone,
2610                         struct zone *zone, unsigned int order,
2611                         gfp_t gfp_flags, unsigned int alloc_flags,
2612                         int migratetype)
2613 {
2614         unsigned long flags;
2615         struct page *page;
2616         bool cold = ((gfp_flags & __GFP_COLD) != 0);
2617 
2618         if (likely(order == 0)) {
2619                 struct per_cpu_pages *pcp;
2620                 struct list_head *list;
2621 
2622                 local_irq_save(flags);
2623                 do {
2624                         pcp = &this_cpu_ptr(zone->pageset)->pcp;
2625                         list = &pcp->lists[migratetype];
2626                         if (list_empty(list)) {
2627                                 pcp->count += rmqueue_bulk(zone, 0,
2628                                                 pcp->batch, list,
2629                                                 migratetype, cold);
2630                                 if (unlikely(list_empty(list)))
2631                                         goto failed;
2632                         }
2633 
2634                         if (cold)
2635                                 page = list_last_entry(list, struct page, lru);
2636                         else
2637                                 page = list_first_entry(list, struct page, lru);
2638 
2639                         list_del(&page->lru);
2640                         pcp->count--;
2641 
2642                 } while (check_new_pcp(page));
2643         } else {
2644                 /*
2645                  * We most definitely don't want callers attempting to
2646                  * allocate greater than order-1 page units with __GFP_NOFAIL.
2647                  */
2648                 WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
2649                 spin_lock_irqsave(&zone->lock, flags);
2650 
2651                 do {
2652                         page = NULL;
2653                         if (alloc_flags & ALLOC_HARDER) {
2654                                 page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
2655                                 if (page)
2656                                         trace_mm_page_alloc_zone_locked(page, order, migratetype);
2657                         }
2658                         if (!page)
2659                                 page = __rmqueue(zone, order, migratetype);
2660                 } while (page && check_new_pages(page, order));
2661                 spin_unlock(&zone->lock);
2662                 if (!page)
2663                         goto failed;
2664                 __mod_zone_freepage_state(zone, -(1 << order),
2665                                           get_pcppage_migratetype(page));
2666         }
2667 
2668         __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
2669         zone_statistics(preferred_zone, zone);
2670         local_irq_restore(flags);
2671 
2672         VM_BUG_ON_PAGE(bad_range(zone, page), page);
2673         return page;
2674 
2675 failed:
2676         local_irq_restore(flags);
2677         return NULL;
2678 }
2679 
2680 #ifdef CONFIG_FAIL_PAGE_ALLOC
2681 
2682 static struct {
2683         struct fault_attr attr;
2684 
2685         bool ignore_gfp_highmem;
2686         bool ignore_gfp_reclaim;
2687         u32 min_order;
2688 } fail_page_alloc = {
2689         .attr = FAULT_ATTR_INITIALIZER,
2690         .ignore_gfp_reclaim = true,
2691         .ignore_gfp_highmem = true,
2692         .min_order = 1,
2693 };
2694 
2695 static int __init setup_fail_page_alloc(char *str)
2696 {
2697         return setup_fault_attr(&fail_page_alloc.attr, str);
2698 }
2699 __setup("fail_page_alloc=", setup_fail_page_alloc);
2700 
2701 static bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
2702 {
2703         if (order < fail_page_alloc.min_order)
2704                 return false;
2705         if (gfp_mask & __GFP_NOFAIL)
2706                 return false;
2707         if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
2708                 return false;
2709         if (fail_page_alloc.ignore_gfp_reclaim &&
2710                         (gfp_mask & __GFP_DIRECT_RECLAIM))
2711                 return false;
2712 
2713         return should_fail(&fail_page_alloc.attr, 1 << order);
2714 }
2715 
2716 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
2717 
2718 static int __init fail_page_alloc_debugfs(void)
2719 {
2720         umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
2721         struct dentry *dir;
2722 
2723         dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
2724                                         &fail_page_alloc.attr);
2725         if (IS_ERR(dir))
2726                 return PTR_ERR(dir);
2727 
2728         if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
2729                                 &fail_page_alloc.ignore_gfp_reclaim))
2730                 goto fail;
2731         if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir,
2732                                 &fail_page_alloc.ignore_gfp_highmem))
2733                 goto fail;
2734         if (!debugfs_create_u32("min-order", mode, dir,
2735                                 &fail_page_alloc.min_order))
2736                 goto fail;
2737 
2738         return 0;
2739 fail:
2740         debugfs_remove_recursive(dir);
2741 
2742         return -ENOMEM;
2743 }
2744 
2745 late_initcall(fail_page_alloc_debugfs);
2746 
2747 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
2748 
2749 #else /* CONFIG_FAIL_PAGE_ALLOC */
2750 
2751 static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
2752 {
2753         return false;
2754 }
2755 
2756 #endif /* CONFIG_FAIL_PAGE_ALLOC */
2757 
2758 /*
2759  * Return true if free base pages are above 'mark'. For high-order checks it
2760  * will return true of the order-0 watermark is reached and there is at least
2761  * one free page of a suitable size. Checking now avoids taking the zone lock
2762  * to check in the allocation paths if no pages are free.
2763  */
2764 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
2765                          int classzone_idx, unsigned int alloc_flags,
2766                          long free_pages)
2767 {
2768         long min = mark;
2769         int o;
2770         const bool alloc_harder = (alloc_flags & ALLOC_HARDER);
2771 
2772         /* free_pages may go negative - that's OK */
2773         free_pages -= (1 << order) - 1;
2774 
2775         if (alloc_flags & ALLOC_HIGH)
2776                 min -= min / 2;
2777 
2778         /*
2779          * If the caller does not have rights to ALLOC_HARDER then subtract
2780          * the high-atomic reserves. This will over-estimate the size of the
2781          * atomic reserve but it avoids a search.
2782          */
2783         if (likely(!alloc_harder))
2784                 free_pages -= z->nr_reserved_highatomic;
2785         else
2786                 min -= min / 4;
2787 
2788 #ifdef CONFIG_CMA
2789         /* If allocation can't use CMA areas don't use free CMA pages */
2790         if (!(alloc_flags & ALLOC_CMA))
2791                 free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
2792 #endif
2793 
2794         /*
2795          * Check watermarks for an order-0 allocation request. If these
2796          * are not met, then a high-order request also cannot go ahead
2797          * even if a suitable page happened to be free.
2798          */
2799         if (free_pages <= min + z->lowmem_reserve[classzone_idx])
2800                 return false;
2801 
2802         /* If this is an order-0 request then the watermark is fine */
2803         if (!order)
2804                 return true;
2805 
2806         /* For a high-order request, check at least one suitable page is free */
2807         for (o = order; o < MAX_ORDER; o++) {
2808                 struct free_area *area = &z->free_area[o];
2809                 int mt;
2810 
2811                 if (!area->nr_free)
2812                         continue;
2813 
2814                 if (alloc_harder)
2815                         return true;
2816 
2817                 for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
2818                         if (!list_empty(&area->free_list[mt]))
2819                                 return true;
2820                 }
2821 
2822 #ifdef CONFIG_CMA
2823                 if ((alloc_flags & ALLOC_CMA) &&
2824                     !list_empty(&area->free_list[MIGRATE_CMA])) {
2825                         return true;
2826                 }
2827 #endif
2828         }
2829         return false;
2830 }
2831 
2832 bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
2833                       int classzone_idx, unsigned int alloc_flags)
2834 {
2835         return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
2836                                         zone_page_state(z, NR_FREE_PAGES));
2837 }
2838 
2839 static inline bool zone_watermark_fast(struct zone *z, unsigned int order,
2840                 unsigned long mark, int classzone_idx, unsigned int alloc_flags)
2841 {
2842         long free_pages = zone_page_state(z, NR_FREE_PAGES);
2843         long cma_pages = 0;
2844 
2845 #ifdef CONFIG_CMA
2846         /* If allocation can't use CMA areas don't use free CMA pages */
2847         if (!(alloc_flags & ALLOC_CMA))
2848                 cma_pages = zone_page_state(z, NR_FREE_CMA_PAGES);
2849 #endif
2850 
2851         /*
2852          * Fast check for order-0 only. If this fails then the reserves
2853          * need to be calculated. There is a corner case where the check
2854          * passes but only the high-order atomic reserve are free. If
2855          * the caller is !atomic then it'll uselessly search the free
2856          * list. That corner case is then slower but it is harmless.
2857          */
2858         if (!order && (free_pages - cma_pages) > mark + z->lowmem_reserve[classzone_idx])
2859                 return true;
2860 
2861         return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
2862                                         free_pages);
2863 }
2864 
2865 bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
2866                         unsigned long mark, int classzone_idx)
2867 {
2868         long free_pages = zone_page_state(z, NR_FREE_PAGES);
2869 
2870         if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
2871                 free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
2872 
2873         return __zone_watermark_ok(z, order, mark, classzone_idx, 0,
2874                                                                 free_pages);
2875 }
2876 
2877 #ifdef CONFIG_NUMA
2878 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
2879 {
2880         return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <
2881                                 RECLAIM_DISTANCE;
2882 }
2883 #else   /* CONFIG_NUMA */
2884 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
2885 {
2886         return true;
2887 }
2888 #endif  /* CONFIG_NUMA */
2889 
2890 /*
2891  * get_page_from_freelist goes through the zonelist trying to allocate
2892  * a page.
2893  */
2894 static struct page *
2895 get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
2896                                                 const struct alloc_context *ac)
2897 {
2898         struct zoneref *z = ac->preferred_zoneref;
2899         struct zone *zone;
2900         struct pglist_data *last_pgdat_dirty_limit = NULL;
2901 
2902         /*
2903          * Scan zonelist, looking for a zone with enough free.
2904          * See also __cpuset_node_allowed() comment in kernel/cpuset.c.
2905          */
2906         for_next_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
2907                                                                 ac->nodemask) {
2908                 struct page *page;
2909                 unsigned long mark;
2910 
2911                 if (cpusets_enabled() &&
2912                         (alloc_flags & ALLOC_CPUSET) &&
2913                         !__cpuset_zone_allowed(zone, gfp_mask))
2914                                 continue;
2915                 /*
2916                  * When allocating a page cache page for writing, we
2917                  * want to get it from a node that is within its dirty
2918                  * limit, such that no single node holds more than its
2919                  * proportional share of globally allowed dirty pages.
2920                  * The dirty limits take into account the node's
2921                  * lowmem reserves and high watermark so that kswapd
2922                  * should be able to balance it without having to
2923                  * write pages from its LRU list.
2924                  *
2925                  * XXX: For now, allow allocations to potentially
2926                  * exceed the per-node dirty limit in the slowpath
2927                  * (spread_dirty_pages unset) before going into reclaim,
2928                  * which is important when on a NUMA setup the allowed
2929                  * nodes are together not big enough to reach the
2930                  * global limit.  The proper fix for these situations
2931                  * will require awareness of nodes in the
2932                  * dirty-throttling and the flusher threads.
2933                  */
2934                 if (ac->spread_dirty_pages) {
2935                         if (last_pgdat_dirty_limit == zone->zone_pgdat)
2936                                 continue;
2937 
2938                         if (!node_dirty_ok(zone->zone_pgdat)) {
2939                                 last_pgdat_dirty_limit = zone->zone_pgdat;
2940                                 continue;
2941                         }
2942                 }
2943 
2944                 mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
2945                 if (!zone_watermark_fast(zone, order, mark,
2946                                        ac_classzone_idx(ac), alloc_flags)) {
2947                         int ret;
2948 
2949                         /* Checked here to keep the fast path fast */
2950                         BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
2951                         if (alloc_flags & ALLOC_NO_WATERMARKS)
2952                                 goto try_this_zone;
2953 
2954                         if (node_reclaim_mode == 0 ||
2955                             !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
2956                                 continue;
2957 
2958                         ret = node_reclaim(zone->zone_pgdat, gfp_mask, order);
2959                         switch (ret) {
2960                         case NODE_RECLAIM_NOSCAN:
2961                                 /* did not scan */
2962                                 continue;
2963                         case NODE_RECLAIM_FULL:
2964                                 /* scanned but unreclaimable */
2965                                 continue;
2966                         default:
2967                                 /* did we reclaim enough */
2968                                 if (zone_watermark_ok(zone, order, mark,
2969                                                 ac_classzone_idx(ac), alloc_flags))
2970                                         goto try_this_zone;
2971 
2972                                 continue;
2973                         }
2974                 }
2975 
2976 try_this_zone:
2977                 page = buffered_rmqueue(ac->preferred_zoneref->zone, zone, order,
2978                                 gfp_mask, alloc_flags, ac->migratetype);
2979                 if (page) {
2980                         prep_new_page(page, order, gfp_mask, alloc_flags);
2981 
2982                         /*
2983                          * If this is a high-order atomic allocation then check
2984                          * if the pageblock should be reserved for the future
2985                          */
2986                         if (unlikely(order && (alloc_flags & ALLOC_HARDER)))
2987                                 reserve_highatomic_pageblock(page, zone, order);
2988 
2989                         return page;
2990                 }
2991         }
2992 
2993         return NULL;
2994 }
2995 
2996 /*
2997  * Large machines with many possible nodes should not always dump per-node
2998  * meminfo in irq context.
2999  */
3000 static inline bool should_suppress_show_mem(void)
3001 {
3002         bool ret = false;
3003 
3004 #if NODES_SHIFT > 8
3005         ret = in_interrupt();
3006 #endif
3007         return ret;
3008 }
3009 
3010 static DEFINE_RATELIMIT_STATE(nopage_rs,
3011                 DEFAULT_RATELIMIT_INTERVAL,
3012                 DEFAULT_RATELIMIT_BURST);
3013 
3014 void warn_alloc(gfp_t gfp_mask, const char *fmt, ...)
3015 {
3016         unsigned int filter = SHOW_MEM_FILTER_NODES;
3017         struct va_format vaf;
3018         va_list args;
3019 
3020         if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) ||
3021             debug_guardpage_minorder() > 0)
3022                 return;
3023 
3024         /*
3025          * This documents exceptions given to allocations in certain
3026          * contexts that are allowed to allocate outside current's set
3027          * of allowed nodes.
3028          */
3029         if (!(gfp_mask & __GFP_NOMEMALLOC))
3030                 if (test_thread_flag(TIF_MEMDIE) ||
3031                     (current->flags & (PF_MEMALLOC | PF_EXITING)))
3032                         filter &= ~SHOW_MEM_FILTER_NODES;
3033         if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
3034                 filter &= ~SHOW_MEM_FILTER_NODES;
3035 
3036         pr_warn("%s: ", current->comm);
3037 
3038         va_start(args, fmt);
3039         vaf.fmt = fmt;
3040         vaf.va = &args;
3041         pr_cont("%pV", &vaf);
3042         va_end(args);
3043 
3044         pr_cont(", mode:%#x(%pGg)\n", gfp_mask, &gfp_mask);
3045 
3046         dump_stack();
3047         if (!should_suppress_show_mem())
3048                 show_mem(filter);
3049 }
3050 
3051 static inline struct page *
3052 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
3053         const struct alloc_context *ac, unsigned long *did_some_progress)
3054 {
3055         struct oom_control oc = {
3056                 .zonelist = ac->zonelist,
3057                 .nodemask = ac->nodemask,
3058                 .memcg = NULL,
3059                 .gfp_mask = gfp_mask,
3060                 .order = order,
3061         };
3062         struct page *page;
3063 
3064         *did_some_progress = 0;
3065 
3066         /*
3067          * Acquire the oom lock.  If that fails, somebody else is
3068          * making progress for us.
3069          */
3070         if (!mutex_trylock(&oom_lock)) {
3071                 *did_some_progress = 1;
3072                 schedule_timeout_uninterruptible(1);
3073                 return NULL;
3074         }
3075 
3076         /*
3077          * Go through the zonelist yet one more time, keep very high watermark
3078          * here, this is only to catch a parallel oom killing, we must fail if
3079          * we're still under heavy pressure.
3080          */
3081         page = get_page_from_freelist(gfp_mask | __GFP_HARDWALL, order,
3082                                         ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
3083         if (page)
3084                 goto out;
3085 
3086         if (!(gfp_mask & __GFP_NOFAIL)) {
3087                 /* Coredumps can quickly deplete all memory reserves */
3088                 if (current->flags & PF_DUMPCORE)
3089                         goto out;
3090                 /* The OOM killer will not help higher order allocs */
3091                 if (order > PAGE_ALLOC_COSTLY_ORDER)
3092                         goto out;
3093                 /* The OOM killer does not needlessly kill tasks for lowmem */
3094                 if (ac->high_zoneidx < ZONE_NORMAL)
3095                         goto out;
3096                 if (pm_suspended_storage())
3097                         goto out;
3098                 /*
3099                  * XXX: GFP_NOFS allocations should rather fail than rely on
3100                  * other request to make a forward progress.
3101                  * We are in an unfortunate situation where out_of_memory cannot
3102                  * do much for this context but let's try it to at least get
3103                  * access to memory reserved if the current task is killed (see
3104                  * out_of_memory). Once filesystems are ready to handle allocation
3105                  * failures more gracefully we should just bail out here.
3106                  */
3107 
3108                 /* The OOM killer may not free memory on a specific node */
3109                 if (gfp_mask & __GFP_THISNODE)
3110                         goto out;
3111         }
3112         /* Exhausted what can be done so it's blamo time */
3113         if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
3114                 *did_some_progress = 1;
3115 
3116                 if (gfp_mask & __GFP_NOFAIL) {
3117                         page = get_page_from_freelist(gfp_mask, order,
3118                                         ALLOC_NO_WATERMARKS|ALLOC_CPUSET, ac);
3119                         /*
3120                          * fallback to ignore cpuset restriction if our nodes
3121                          * are depleted
3122                          */
3123                         if (!page)
3124                                 page = get_page_from_freelist(gfp_mask, order,
3125                                         ALLOC_NO_WATERMARKS, ac);
3126                 }
3127         }
3128 out:
3129         mutex_unlock(&oom_lock);
3130         return page;
3131 }
3132 
3133 /*
3134  * Maximum number of compaction retries wit a progress before OOM
3135  * killer is consider as the only way to move forward.
3136  */
3137 #define MAX_COMPACT_RETRIES 16
3138 
3139 #ifdef CONFIG_COMPACTION
3140 /* Try memory compaction for high-order allocations before reclaim */
3141 static struct page *
3142 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
3143                 unsigned int alloc_flags, const struct alloc_context *ac,
3144                 enum compact_priority prio, enum compact_result *compact_result)
3145 {
3146         struct page *page;
3147 
3148         if (!order)
3149                 return NULL;
3150 
3151         current->flags |= PF_MEMALLOC;
3152         *compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
3153                                                                         prio);
3154         current->flags &= ~PF_MEMALLOC;
3155 
3156         if (*compact_result <= COMPACT_INACTIVE)
3157                 return NULL;
3158 
3159         /*
3160          * At least in one zone compaction wasn't deferred or skipped, so let's
3161          * count a compaction stall
3162          */
3163         count_vm_event(COMPACTSTALL);
3164 
3165         page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3166 
3167         if (page) {
3168                 struct zone *zone = page_zone(page);
3169 
3170                 zone->compact_blockskip_flush = false;
3171                 compaction_defer_reset(zone, order, true);
3172                 count_vm_event(COMPACTSUCCESS);
3173                 return page;
3174         }
3175 
3176         /*
3177          * It's bad if compaction run occurs and fails. The most likely reason
3178          * is that pages exist, but not enough to satisfy watermarks.
3179          */
3180         count_vm_event(COMPACTFAIL);
3181 
3182         cond_resched();
3183 
3184         return NULL;
3185 }
3186 
3187 static inline bool
3188 should_compact_retry(struct alloc_context *ac, int order, int alloc_flags,
3189                      enum compact_result compact_result,
3190                      enum compact_priority *compact_priority,
3191                      int *compaction_retries)
3192 {
3193         int max_retries = MAX_COMPACT_RETRIES;
3194         int min_priority;
3195 
3196         if (!order)
3197                 return false;
3198 
3199         if (compaction_made_progress(compact_result))
3200                 (*compaction_retries)++;
3201 
3202         /*
3203          * compaction considers all the zone as desperately out of memory
3204          * so it doesn't really make much sense to retry except when the
3205          * failure could be caused by insufficient priority
3206          */
3207         if (compaction_failed(compact_result))
3208                 goto check_priority;
3209 
3210         /*
3211          * make sure the compaction wasn't deferred or didn't bail out early
3212          * due to locks contention before we declare that we should give up.
3213          * But do not retry if the given zonelist is not suitable for
3214          * compaction.
3215          */
3216         if (compaction_withdrawn(compact_result))
3217                 return compaction_zonelist_suitable(ac, order, alloc_flags);
3218 
3219         /*
3220          * !costly requests are much more important than __GFP_REPEAT
3221          * costly ones because they are de facto nofail and invoke OOM
3222          * killer to move on while costly can fail and users are ready
3223          * to cope with that. 1/4 retries is rather arbitrary but we
3224          * would need much more detailed feedback from compaction to
3225          * make a better decision.
3226          */
3227         if (order > PAGE_ALLOC_COSTLY_ORDER)
3228                 max_retries /= 4;
3229         if (*compaction_retries <= max_retries)
3230                 return true;
3231 
3232         /*
3233          * Make sure there are attempts at the highest priority if we exhausted
3234          * all retries or failed at the lower priorities.
3235          */
3236 check_priority:
3237         min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ?
3238                         MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;
3239         if (*compact_priority > min_priority) {
3240                 (*compact_priority)--;
3241                 *compaction_retries = 0;
3242                 return true;
3243         }
3244         return false;
3245 }
3246 #else
3247 static inline struct page *
3248 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
3249                 unsigned int alloc_flags, const struct alloc_context *ac,
3250                 enum compact_priority prio, enum compact_result *compact_result)
3251 {
3252         *compact_result = COMPACT_SKIPPED;
3253         return NULL;
3254 }
3255 
3256 static inline bool
3257 should_compact_retry(struct alloc_context *ac, unsigned int order, int alloc_flags,
3258                      enum compact_result compact_result,
3259                      enum compact_priority *compact_priority,
3260                      int *compaction_retries)
3261 {
3262         struct zone *zone;
3263         struct zoneref *z;
3264 
3265         if (!order || order > PAGE_ALLOC_COSTLY_ORDER)
3266                 return false;
3267 
3268         /*
3269          * There are setups with compaction disabled which would prefer to loop
3270          * inside the allocator rather than hit the oom killer prematurely.
3271          * Let's give them a good hope and keep retrying while the order-0
3272          * watermarks are OK.
3273          */
3274         for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
3275                                         ac->nodemask) {
3276                 if (zone_watermark_ok(zone, 0, min_wmark_pages(zone),
3277                                         ac_classzone_idx(ac), alloc_flags))
3278                         return true;
3279         }
3280         return false;
3281 }
3282 #endif /* CONFIG_COMPACTION */
3283 
3284 /* Perform direct synchronous page reclaim */
3285 static int
3286 __perform_reclaim(gfp_t gfp_mask, unsigned int order,
3287                                         const struct alloc_context *ac)
3288 {
3289         struct reclaim_state reclaim_state;
3290         int progress;
3291 
3292         cond_resched();
3293 
3294         /* We now go into synchronous reclaim */
3295         cpuset_memory_pressure_bump();
3296         current->flags |= PF_MEMALLOC;
3297         lockdep_set_current_reclaim_state(gfp_mask);
3298         reclaim_state.reclaimed_slab = 0;
3299         current->reclaim_state = &reclaim_state;
3300 
3301         progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
3302                                                                 ac->nodemask);
3303 
3304         current->reclaim_state = NULL;
3305         lockdep_clear_current_reclaim_state();
3306         current->flags &= ~PF_MEMALLOC;
3307 
3308         cond_resched();
3309 
3310         return progress;
3311 }
3312 
3313 /* The really slow allocator path where we enter direct reclaim */
3314 static inline struct page *
3315 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
3316                 unsigned int alloc_flags, const struct alloc_context *ac,
3317                 unsigned long *did_some_progress)
3318 {
3319         struct page *page = NULL;
3320         bool drained = false;
3321 
3322         *did_some_progress = __perform_reclaim(gfp_mask, order, ac);
3323         if (unlikely(!(*did_some_progress)))
3324                 return NULL;
3325 
3326 retry:
3327         page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3328 
3329         /*
3330          * If an allocation failed after direct reclaim, it could be because
3331          * pages are pinned on the per-cpu lists or in high alloc reserves.
3332          * Shrink them them and try again
3333          */
3334         if (!page && !drained) {
3335                 unreserve_highatomic_pageblock(ac, false);
3336                 drain_all_pages(NULL);
3337                 drained = true;
3338                 goto retry;
3339         }
3340 
3341         return page;
3342 }
3343 
3344 static void wake_all_kswapds(unsigned int order, const struct alloc_context *ac)
3345 {
3346         struct zoneref *z;
3347         struct zone *zone;
3348         pg_data_t *last_pgdat = NULL;
3349 
3350         for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
3351                                         ac->high_zoneidx, ac->nodemask) {
3352                 if (last_pgdat != zone->zone_pgdat)
3353                         wakeup_kswapd(zone, order, ac->high_zoneidx);
3354                 last_pgdat = zone->zone_pgdat;
3355         }
3356 }
3357 
3358 static inline unsigned int
3359 gfp_to_alloc_flags(gfp_t gfp_mask)
3360 {
3361         unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
3362 
3363         /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
3364         BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
3365 
3366         /*
3367          * The caller may dip into page reserves a bit more if the caller
3368          * cannot run direct reclaim, or if the caller has realtime scheduling
3369          * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
3370          * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
3371          */
3372         alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
3373 
3374         if (gfp_mask & __GFP_ATOMIC) {
3375                 /*
3376                  * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
3377                  * if it can't schedule.
3378                  */
3379                 if (!(gfp_mask & __GFP_NOMEMALLOC))
3380                         alloc_flags |= ALLOC_HARDER;
3381                 /*
3382                  * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
3383                  * comment for __cpuset_node_allowed().
3384                  */
3385                 alloc_flags &= ~ALLOC_CPUSET;
3386         } else if (unlikely(rt_task(current)) && !in_interrupt())
3387                 alloc_flags |= ALLOC_HARDER;
3388 
3389 #ifdef CONFIG_CMA
3390         if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
3391                 alloc_flags |= ALLOC_CMA;
3392 #endif
3393         return alloc_flags;
3394 }
3395 
3396 bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
3397 {
3398         if (unlikely(gfp_mask & __GFP_NOMEMALLOC))
3399                 return false;
3400 
3401         if (gfp_mask & __GFP_MEMALLOC)
3402                 return true;
3403         if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
3404                 return true;
3405         if (!in_interrupt() &&
3406                         ((current->flags & PF_MEMALLOC) ||
3407                          unlikely(test_thread_flag(TIF_MEMDIE))))
3408                 return true;
3409 
3410         return false;
3411 }
3412 
3413 /*
3414  * Maximum number of reclaim retries without any progress before OOM killer
3415  * is consider as the only way to move forward.
3416  */
3417 #define MAX_RECLAIM_RETRIES 16
3418 
3419 /*
3420  * Checks whether it makes sense to retry the reclaim to make a forward progress
3421  * for the given allocation request.
3422  * The reclaim feedback represented by did_some_progress (any progress during
3423  * the last reclaim round) and no_progress_loops (number of reclaim rounds without
3424  * any progress in a row) is considered as well as the reclaimable pages on the
3425  * applicable zone list (with a backoff mechanism which is a function of
3426  * no_progress_loops).
3427  *
3428  * Returns true if a retry is viable or false to enter the oom path.
3429  */
3430 static inline bool
3431 should_reclaim_retry(gfp_t gfp_mask, unsigned order,
3432                      struct alloc_context *ac, int alloc_flags,
3433                      bool did_some_progress, int *no_progress_loops)
3434 {
3435         struct zone *zone;
3436         struct zoneref *z;
3437 
3438         /*
3439          * Costly allocations might have made a progress but this doesn't mean
3440          * their order will become available due to high fragmentation so
3441          * always increment the no progress counter for them
3442          */
3443         if (did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER)
3444                 *no_progress_loops = 0;
3445         else
3446                 (*no_progress_loops)++;
3447 
3448         /*
3449          * Make sure we converge to OOM if we cannot make any progress
3450          * several times in the row.
3451          */
3452         if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
3453                 /* Before OOM, exhaust highatomic_reserve */
3454                 return unreserve_highatomic_pageblock(ac, true);
3455         }
3456 
3457         /*
3458          * Keep reclaiming pages while there is a chance this will lead
3459          * somewhere.  If none of the target zones can satisfy our allocation
3460          * request even if all reclaimable pages are considered then we are
3461          * screwed and have to go OOM.
3462          */
3463         for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
3464                                         ac->nodemask) {
3465                 unsigned long available;
3466                 unsigned long reclaimable;
3467 
3468                 available = reclaimable = zone_reclaimable_pages(zone);
3469                 available -= DIV_ROUND_UP((*no_progress_loops) * available,
3470                                           MAX_RECLAIM_RETRIES);
3471                 available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
3472 
3473                 /*
3474                  * Would the allocation succeed if we reclaimed the whole
3475                  * available?
3476                  */
3477                 if (__zone_watermark_ok(zone, order, min_wmark_pages(zone),
3478                                 ac_classzone_idx(ac), alloc_flags, available)) {
3479                         /*
3480                          * If we didn't make any progress and have a lot of
3481                          * dirty + writeback pages then we should wait for
3482                          * an IO to complete to slow down the reclaim and
3483                          * prevent from pre mature OOM
3484                          */
3485                         if (!did_some_progress) {
3486                                 unsigned long write_pending;
3487 
3488                                 write_pending = zone_page_state_snapshot(zone,
3489                                                         NR_ZONE_WRITE_PENDING);
3490 
3491                                 if (2 * write_pending > reclaimable) {
3492                                         congestion_wait(BLK_RW_ASYNC, HZ/10);
3493                                         return true;
3494                                 }
3495                         }
3496 
3497                         /*
3498                          * Memory allocation/reclaim might be called from a WQ
3499                          * context and the current implementation of the WQ
3500                          * concurrency control doesn't recognize that
3501                          * a particular WQ is congested if the worker thread is
3502                          * looping without ever sleeping. Therefore we have to
3503                          * do a short sleep here rather than calling
3504                          * cond_resched().
3505                          */
3506                         if (current->flags & PF_WQ_WORKER)
3507                                 schedule_timeout_uninterruptible(1);
3508                         else
3509                                 cond_resched();
3510 
3511                         return true;
3512                 }
3513         }
3514 
3515         return false;
3516 }
3517 
3518 static inline struct page *
3519 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
3520                                                 struct alloc_context *ac)
3521 {
3522         bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
3523         struct page *page = NULL;
3524         unsigned int alloc_flags;
3525         unsigned long did_some_progress;
3526         enum compact_priority compact_priority;
3527         enum compact_result compact_result;
3528         int compaction_retries;
3529         int no_progress_loops;
3530         unsigned long alloc_start = jiffies;
3531         unsigned int stall_timeout = 10 * HZ;
3532         unsigned int cpuset_mems_cookie;
3533 
3534         /*
3535          * In the slowpath, we sanity check order to avoid ever trying to
3536          * reclaim >= MAX_ORDER areas which will never succeed. Callers may
3537          * be using allocators in order of preference for an area that is
3538          * too large.
3539          */
3540         if (order >= MAX_ORDER) {
3541                 WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
3542                 return NULL;
3543         }
3544 
3545         /*
3546          * We also sanity check to catch abuse of atomic reserves being used by
3547          * callers that are not in atomic context.
3548          */
3549         if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) ==
3550                                 (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
3551                 gfp_mask &= ~__GFP_ATOMIC;
3552 
3553 retry_cpuset:
3554         compaction_retries = 0;
3555         no_progress_loops = 0;
3556         compact_priority = DEF_COMPACT_PRIORITY;
3557         cpuset_mems_cookie = read_mems_allowed_begin();
3558         /*
3559          * We need to recalculate the starting point for the zonelist iterator
3560          * because we might have used different nodemask in the fast path, or
3561          * there was a cpuset modification and we are retrying - otherwise we
3562          * could end up iterating over non-eligible zones endlessly.
3563          */
3564         ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
3565                                         ac->high_zoneidx, ac->nodemask);
3566         if (!ac->preferred_zoneref->zone)
3567                 goto nopage;
3568 
3569 
3570         /*
3571          * The fast path uses conservative alloc_flags to succeed only until
3572          * kswapd needs to be woken up, and to avoid the cost of setting up
3573          * alloc_flags precisely. So we do that now.
3574          */
3575         alloc_flags = gfp_to_alloc_flags(gfp_mask);
3576 
3577         if (gfp_mask & __GFP_KSWAPD_RECLAIM)
3578                 wake_all_kswapds(order, ac);
3579 
3580         /*
3581          * The adjusted alloc_flags might result in immediate success, so try
3582          * that first
3583          */
3584         page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3585         if (page)
3586                 goto got_pg;
3587 
3588         /*
3589          * For costly allocations, try direct compaction first, as it's likely
3590          * that we have enough base pages and don't need to reclaim. Don't try
3591          * that for allocations that are allowed to ignore watermarks, as the
3592          * ALLOC_NO_WATERMARKS attempt didn't yet happen.
3593          */
3594         if (can_direct_reclaim && order > PAGE_ALLOC_COSTLY_ORDER &&
3595                 !gfp_pfmemalloc_allowed(gfp_mask)) {
3596                 page = __alloc_pages_direct_compact(gfp_mask, order,
3597                                                 alloc_flags, ac,
3598                                                 INIT_COMPACT_PRIORITY,
3599                                                 &compact_result);
3600                 if (page)
3601                         goto got_pg;
3602 
3603                 /*
3604                  * Checks for costly allocations with __GFP_NORETRY, which
3605                  * includes THP page fault allocations
3606                  */
3607                 if (gfp_mask & __GFP_NORETRY) {
3608                         /*
3609                          * If compaction is deferred for high-order allocations,
3610                          * it is because sync compaction recently failed. If
3611                          * this is the case and the caller requested a THP
3612                          * allocation, we do not want to heavily disrupt the
3613                          * system, so we fail the allocation instead of entering
3614                          * direct reclaim.
3615                          */
3616                         if (compact_result == COMPACT_DEFERRED)
3617                                 goto nopage;
3618 
3619                         /*
3620                          * Looks like reclaim/compaction is worth trying, but
3621                          * sync compaction could be very expensive, so keep
3622                          * using async compaction.
3623                          */
3624                         compact_priority = INIT_COMPACT_PRIORITY;
3625                 }
3626         }
3627 
3628 retry:
3629         /* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
3630         if (gfp_mask & __GFP_KSWAPD_RECLAIM)
3631                 wake_all_kswapds(order, ac);
3632 
3633         if (gfp_pfmemalloc_allowed(gfp_mask))
3634                 alloc_flags = ALLOC_NO_WATERMARKS;
3635 
3636         /*
3637          * Reset the zonelist iterators if memory policies can be ignored.
3638          * These allocations are high priority and system rather than user
3639          * orientated.
3640          */
3641         if (!(alloc_flags & ALLOC_CPUSET) || (alloc_flags & ALLOC_NO_WATERMARKS)) {
3642                 ac->zonelist = node_zonelist(numa_node_id(), gfp_mask);
3643                 ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
3644                                         ac->high_zoneidx, ac->nodemask);
3645         }
3646 
3647         /* Attempt with potentially adjusted zonelist and alloc_flags */
3648         page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
3649         if (page)
3650                 goto got_pg;
3651 
3652         /* Caller is not willing to reclaim, we can't balance anything */
3653         if (!can_direct_reclaim) {
3654                 /*
3655                  * All existing users of the __GFP_NOFAIL are blockable, so warn
3656                  * of any new users that actually allow this type of allocation
3657                  * to fail.
3658                  */
3659                 WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL);
3660                 goto nopage;
3661         }
3662 
3663         /* Avoid recursion of direct reclaim */
3664         if (current->flags & PF_MEMALLOC) {
3665                 /*
3666                  * __GFP_NOFAIL request from this context is rather bizarre
3667                  * because we cannot reclaim anything and only can loop waiting
3668                  * for somebody to do a work for us.
3669                  */
3670                 if (WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL)) {
3671                         cond_resched();
3672                         goto retry;
3673                 }
3674                 goto nopage;
3675         }
3676 
3677         /* Avoid allocations with no watermarks from looping endlessly */
3678         if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
3679                 goto nopage;
3680 
3681 
3682         /* Try direct reclaim and then allocating */
3683         page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
3684                                                         &did_some_progress);
3685         if (page)
3686                 goto got_pg;
3687 
3688         /* Try direct compaction and then allocating */
3689         page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
3690                                         compact_priority, &compact_result);
3691         if (page)
3692                 goto got_pg;
3693 
3694         /* Do not loop if specifically requested */
3695         if (gfp_mask & __GFP_NORETRY)
3696                 goto nopage;
3697 
3698         /*
3699          * Do not retry costly high order allocations unless they are
3700          * __GFP_REPEAT
3701          */
3702         if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_REPEAT))
3703                 goto nopage;
3704 
3705         /* Make sure we know about allocations which stall for too long */
3706         if (time_after(jiffies, alloc_start + stall_timeout)) {
3707                 warn_alloc(gfp_mask,
3708                         "page allocation stalls for %ums, order:%u",
3709                         jiffies_to_msecs(jiffies-alloc_start), order);
3710                 stall_timeout += 10 * HZ;
3711         }
3712 
3713         if (should_reclaim_retry(gfp_mask, order, ac, alloc_flags,
3714                                  did_some_progress > 0, &no_progress_loops))
3715                 goto retry;
3716 
3717         /*
3718          * It doesn't make any sense to retry for the compaction if the order-0
3719          * reclaim is not able to make any progress because the current
3720          * implementation of the compaction depends on the sufficient amount
3721          * of free memory (see __compaction_suitable)
3722          */
3723         if (did_some_progress > 0 &&
3724                         should_compact_retry(ac, order, alloc_flags,
3725                                 compact_result, &compact_priority,
3726                                 &compaction_retries))
3727                 goto retry;
3728 
3729         /*
3730          * It's possible we raced with cpuset update so the OOM would be
3731          * premature (see below the nopage: label for full explanation).
3732          */
3733         if (read_mems_allowed_retry(cpuset_mems_cookie))
3734                 goto retry_cpuset;
3735 
3736         /* Reclaim has failed us, start killing things */
3737         page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
3738         if (page)
3739                 goto got_pg;
3740 
3741         /* Retry as long as the OOM killer is making progress */
3742         if (did_some_progress) {
3743                 no_progress_loops = 0;
3744                 goto retry;
3745         }
3746 
3747 nopage:
3748         /*
3749          * When updating a task's mems_allowed or mempolicy nodemask, it is
3750          * possible to race with parallel threads in such a way that our
3751          * allocation can fail while the mask is being updated. If we are about
3752          * to fail, check if the cpuset changed during allocation and if so,
3753          * retry.
3754          */
3755         if (read_mems_allowed_retry(cpuset_mems_cookie))
3756                 goto retry_cpuset;
3757 
3758         warn_alloc(gfp_mask,
3759                         "page allocation failure: order:%u", order);
3760 got_pg:
3761         return page;
3762 }
3763 
3764 /*
3765  * This is the 'heart' of the zoned buddy allocator.
3766  */
3767 struct page *
3768 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
3769                         struct zonelist *zonelist, nodemask_t *nodemask)
3770 {
3771         struct page *page;
3772         unsigned int alloc_flags = ALLOC_WMARK_LOW;
3773         gfp_t alloc_mask = gfp_mask; /* The gfp_t that was actually used for allocation */
3774         struct alloc_context ac = {
3775                 .high_zoneidx = gfp_zone(gfp_mask),
3776                 .zonelist = zonelist,
3777                 .nodemask = nodemask,
3778                 .migratetype = gfpflags_to_migratetype(gfp_mask),
3779         };
3780 
3781         if (cpusets_enabled()) {
3782                 alloc_mask |= __GFP_HARDWALL;
3783                 alloc_flags |= ALLOC_CPUSET;
3784                 if (!ac.nodemask)
3785                         ac.nodemask = &cpuset_current_mems_allowed;
3786         }
3787 
3788         gfp_mask &= gfp_allowed_mask;
3789 
3790         lockdep_trace_alloc(gfp_mask);
3791 
3792         might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
3793 
3794         if (should_fail_alloc_page(gfp_mask, order))
3795                 return NULL;
3796 
3797         /*
3798          * Check the zones suitable for the gfp_mask contain at least one
3799          * valid zone. It's possible to have an empty zonelist as a result
3800          * of __GFP_THISNODE and a memoryless node
3801          */
3802         if (unlikely(!zonelist->_zonerefs->zone))
3803                 return NULL;
3804 
3805         if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE)
3806                 alloc_flags |= ALLOC_CMA;
3807 
3808         /* Dirty zone balancing only done in the fast path */
3809         ac.spread_dirty_pages = (gfp_mask & __GFP_WRITE);
3810 
3811         /*
3812          * The preferred zone is used for statistics but crucially it is
3813          * also used as the starting point for the zonelist iterator. It
3814          * may get reset for allocations that ignore memory policies.
3815          */
3816         ac.preferred_zoneref = first_zones_zonelist(ac.zonelist,
3817                                         ac.high_zoneidx, ac.nodemask);
3818         if (!ac.preferred_zoneref->zone) {
3819                 page = NULL;
3820                 /*
3821                  * This might be due to race with cpuset_current_mems_allowed
3822                  * update, so make sure we retry with original nodemask in the
3823                  * slow path.
3824                  */
3825                 goto no_zone;
3826         }
3827 
3828         /* First allocation attempt */
3829         page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
3830         if (likely(page))
3831                 goto out;
3832 
3833 no_zone:
3834         /*
3835          * Runtime PM, block IO and its error handling path can deadlock
3836          * because I/O on the device might not complete.
3837          */
3838         alloc_mask = memalloc_noio_flags(gfp_mask);
3839         ac.spread_dirty_pages = false;
3840 
3841         /*
3842          * Restore the original nodemask if it was potentially replaced with
3843          * &cpuset_current_mems_allowed to optimize the fast-path attempt.
3844          */
3845         if (unlikely(ac.nodemask != nodemask))
3846                 ac.nodemask = nodemask;
3847 
3848         page = __alloc_pages_slowpath(alloc_mask, order, &ac);
3849 
3850 out:
3851         if (memcg_kmem_enabled() && (gfp_mask & __GFP_ACCOUNT) && page &&
3852             unlikely(memcg_kmem_charge(page, gfp_mask, order) != 0)) {
3853                 __free_pages(page, order);
3854                 page = NULL;
3855         }
3856 
3857         if (kmemcheck_enabled && page)
3858                 kmemcheck_pagealloc_alloc(page, order, gfp_mask);
3859 
3860         trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);
3861 
3862         return page;
3863 }
3864 EXPORT_SYMBOL(__alloc_pages_nodemask);
3865 
3866 /*
3867  * Common helper functions.
3868  */
3869 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
3870 {
3871         struct page *page;
3872 
3873         /*
3874          * __get_free_pages() returns a 32-bit address, which cannot represent
3875          * a highmem page
3876          */
3877         VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
3878 
3879         page = alloc_pages(gfp_mask, order);
3880         if (!page)
3881                 return 0;
3882         return (unsigned long) page_address(page);
3883 }
3884 EXPORT_SYMBOL(__get_free_pages);
3885 
3886 unsigned long get_zeroed_page(gfp_t gfp_mask)
3887 {
3888         return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
3889 }
3890 EXPORT_SYMBOL(get_zeroed_page);
3891 
3892 void __free_pages(struct page *page, unsigned int order)
3893 {
3894         if (put_page_testzero(page)) {
3895                 if (order == 0)
3896                         free_hot_cold_page(page, false);
3897                 else
3898                         __free_pages_ok(page, order);
3899         }
3900 }
3901 
3902 EXPORT_SYMBOL(__free_pages);
3903 
3904 void free_pages(unsigned long addr, unsigned int order)
3905 {
3906         if (addr != 0) {
3907                 VM_BUG_ON(!virt_addr_valid((void *)addr));
3908                 __free_pages(virt_to_page((void *)addr), order);
3909         }
3910 }
3911 
3912 EXPORT_SYMBOL(free_pages);
3913 
3914 /*
3915  * Page Fragment:
3916  *  An arbitrary-length arbitrary-offset area of memory which resides
3917  *  within a 0 or higher order page.  Multiple fragments within that page
3918  *  are individually refcounted, in the page's reference counter.
3919  *
3920  * The page_frag functions below provide a simple allocation framework for
3921  * page fragments.  This is used by the network stack and network device
3922  * drivers to provide a backing region of memory for use as either an
3923  * sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
3924  */
3925 static struct page *__page_frag_cache_refill(struct page_frag_cache *nc,
3926                                              gfp_t gfp_mask)
3927 {
3928         struct page *page = NULL;
3929         gfp_t gfp = gfp_mask;
3930 
3931 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
3932         gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
3933                     __GFP_NOMEMALLOC;
3934         page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
3935                                 PAGE_FRAG_CACHE_MAX_ORDER);
3936         nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
3937 #endif
3938         if (unlikely(!page))
3939                 page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
3940 
3941         nc->va = page ? page_address(page) : NULL;
3942 
3943         return page;
3944 }
3945 
3946 void __page_frag_cache_drain(struct page *page, unsigned int count)
3947 {
3948         VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
3949 
3950         if (page_ref_sub_and_test(page, count)) {
3951                 unsigned int order = compound_order(page);
3952 
3953                 if (order == 0)
3954                         free_hot_cold_page(page, false);
3955                 else
3956                         __free_pages_ok(page, order);
3957         }
3958 }
3959 EXPORT_SYMBOL(__page_frag_cache_drain);
3960 
3961 void *page_frag_alloc(struct page_frag_cache *nc,
3962                       unsigned int fragsz, gfp_t gfp_mask)
3963 {
3964         unsigned int size = PAGE_SIZE;
3965         struct page *page;
3966         int offset;
3967 
3968         if (unlikely(!nc->va)) {
3969 refill:
3970                 page = __page_frag_cache_refill(nc, gfp_mask);
3971                 if (!page)
3972                         return NULL;
3973 
3974 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
3975                 /* if size can vary use size else just use PAGE_SIZE */
3976                 size = nc->size;
3977 #endif
3978                 /* Even if we own the page, we do not use atomic_set().
3979                  * This would break get_page_unless_zero() users.
3980                  */
3981                 page_ref_add(page, size - 1);
3982 
3983                 /* reset page count bias and offset to start of new frag */
3984                 nc->pfmemalloc = page_is_pfmemalloc(page);
3985                 nc->pagecnt_bias = size;
3986                 nc->offset = size;
3987         }
3988 
3989         offset = nc->offset - fragsz;
3990         if (unlikely(offset < 0)) {
3991                 page = virt_to_page(nc->va);
3992 
3993                 if (!page_ref_sub_and_test(page, nc->pagecnt_bias))
3994                         goto refill;
3995 
3996 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
3997                 /* if size can vary use size else just use PAGE_SIZE */
3998                 size = nc->size;
3999 #endif
4000                 /* OK, page count is 0, we can safely set it */
4001                 set_page_count(page, size);
4002 
4003                 /* reset page count bias and offset to start of new frag */
4004                 nc->pagecnt_bias = size;
4005                 offset = size - fragsz;
4006         }
4007 
4008         nc->pagecnt_bias--;
4009         nc->offset = offset;
4010 
4011         return nc->va + offset;
4012 }
4013 EXPORT_SYMBOL(page_frag_alloc);
4014 
4015 /*
4016  * Frees a page fragment allocated out of either a compound or order 0 page.
4017  */
4018 void page_frag_free(void *addr)
4019 {
4020         struct page *page = virt_to_head_page(addr);
4021 
4022         if (unlikely(put_page_testzero(page)))
4023                 __free_pages_ok(page, compound_order(page));
4024 }
4025 EXPORT_SYMBOL(page_frag_free);
4026 
4027 static void *make_alloc_exact(unsigned long addr, unsigned int order,
4028                 size_t size)
4029 {
4030         if (addr) {
4031                 unsigned long alloc_end = addr + (PAGE_SIZE << order);
4032                 unsigned long used = addr + PAGE_ALIGN(size);
4033 
4034                 split_page(virt_to_page((void *)addr), order);
4035                 while (used < alloc_end) {
4036                         free_page(used);
4037                         used += PAGE_SIZE;
4038                 }
4039         }
4040         return (void *)addr;
4041 }
4042 
4043 /**
4044  * alloc_pages_exact - allocate an exact number physically-contiguous pages.
4045  * @size: the number of bytes to allocate
4046  * @gfp_mask: GFP flags for the allocation
4047  *
4048  * This function is similar to alloc_pages(), except that it allocates the
4049  * minimum number of pages to satisfy the request.  alloc_pages() can only
4050  * allocate memory in power-of-two pages.
4051  *
4052  * This function is also limited by MAX_ORDER.
4053  *
4054  * Memory allocated by this function must be released by free_pages_exact().
4055  */
4056 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
4057 {
4058         unsigned int order = get_order(size);
4059         unsigned long addr;
4060 
4061         addr = __get_free_pages(gfp_mask, order);
4062         return make_alloc_exact(addr, order, size);
4063 }
4064 EXPORT_SYMBOL(alloc_pages_exact);
4065 
4066 /**
4067  * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
4068  *                         pages on a node.
4069  * @nid: the preferred node ID where memory should be allocated
4070  * @size: the number of bytes to allocate
4071  * @gfp_mask: GFP flags for the allocation
4072  *
4073  * Like alloc_pages_exact(), but try to allocate on node nid first before falling
4074  * back.
4075  */
4076 void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
4077 {
4078         unsigned int order = get_order(size);
4079         struct page *p = alloc_pages_node(nid, gfp_mask, order);
4080         if (!p)
4081                 return NULL;
4082         return make_alloc_exact((unsigned long)page_address(p), order, size);
4083 }
4084 
4085 /**
4086  * free_pages_exact - release memory allocated via alloc_pages_exact()
4087  * @virt: the value returned by alloc_pages_exact.
4088  * @size: size of allocation, same value as passed to alloc_pages_exact().
4089  *
4090  * Release the memory allocated by a previous call to alloc_pages_exact.
4091  */
4092 void free_pages_exact(void *virt, size_t size)
4093 {
4094         unsigned long addr = (unsigned long)virt;
4095         unsigned long end = addr + PAGE_ALIGN(size);
4096 
4097         while (addr < end) {
4098                 free_page(addr);
4099                 addr += PAGE_SIZE;
4100         }
4101 }
4102 EXPORT_SYMBOL(free_pages_exact);
4103 
4104 /**
4105  * nr_free_zone_pages - count number of pages beyond high watermark
4106  * @offset: The zone index of the highest zone
4107  *
4108  * nr_free_zone_pages() counts the number of counts pages which are beyond the
4109  * high watermark within all zones at or below a given zone index.  For each
4110  * zone, the number of pages is calculated as:
4111  *     managed_pages - high_pages
4112  */
4113 static unsigned long nr_free_zone_pages(int offset)
4114 {
4115         struct zoneref *z;
4116         struct zone *zone;
4117 
4118         /* Just pick one node, since fallback list is circular */
4119         unsigned long sum = 0;
4120 
4121         struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
4122 
4123         for_each_zone_zonelist(zone, z, zonelist, offset) {
4124                 unsigned long size = zone->managed_pages;
4125                 unsigned long high = high_wmark_pages(zone);
4126                 if (size > high)
4127                         sum += size - high;
4128         }
4129 
4130         return sum;
4131 }
4132 
4133 /**
4134  * nr_free_buffer_pages - count number of pages beyond high watermark
4135  *
4136  * nr_free_buffer_pages() counts the number of pages which are beyond the high
4137  * watermark within ZONE_DMA and ZONE_NORMAL.
4138  */
4139 unsigned long nr_free_buffer_pages(void)
4140 {
4141         return nr_free_zone_pages(gfp_zone(GFP_USER));
4142 }
4143 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
4144 
4145 /**
4146  * nr_free_pagecache_pages - count number of pages beyond high watermark
4147  *
4148  * nr_free_pagecache_pages() counts the number of pages which are beyond the
4149  * high watermark within all zones.
4150  */
4151 unsigned long nr_free_pagecache_pages(void)
4152 {
4153         return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
4154 }
4155 
4156 static inline void show_node(struct zone *zone)
4157 {
4158         if (IS_ENABLED(CONFIG_NUMA))
4159                 printk("Node %d ", zone_to_nid(zone));
4160 }
4161 
4162 long si_mem_available(void)
4163 {
4164         long available;
4165         unsigned long pagecache;
4166         unsigned long wmark_low = 0;
4167         unsigned long pages[NR_LRU_LISTS];
4168         struct zone *zone;
4169         int lru;
4170 
4171         for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
4172                 pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
4173 
4174         for_each_zone(zone)
4175                 wmark_low += zone->watermark[WMARK_LOW];
4176 
4177         /*
4178          * Estimate the amount of memory available for userspace allocations,
4179          * without causing swapping.
4180          */
4181         available = global_page_state(NR_FREE_PAGES) - totalreserve_pages;
4182 
4183         /*
4184          * Not all the page cache can be freed, otherwise the system will
4185          * start swapping. Assume at least half of the page cache, or the
4186          * low watermark worth of cache, needs to stay.
4187          */
4188         pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
4189         pagecache -= min(pagecache / 2, wmark_low);
4190         available += pagecache;
4191 
4192         /*
4193          * Part of the reclaimable slab consists of items that are in use,
4194          * and cannot be freed. Cap this estimate at the low watermark.
4195          */
4196         available += global_page_state(NR_SLAB_RECLAIMABLE) -
4197                      min(global_page_state(NR_SLAB_RECLAIMABLE) / 2, wmark_low);
4198 
4199         if (available < 0)
4200                 available = 0;
4201         return available;
4202 }
4203 EXPORT_SYMBOL_GPL(si_mem_available);
4204 
4205 void si_meminfo(struct sysinfo *val)
4206 {
4207         val->totalram = totalram_pages;
4208         val->sharedram = global_node_page_state(NR_SHMEM);
4209         val->freeram = global_page_state(NR_FREE_PAGES);
4210         val->bufferram = nr_blockdev_pages();
4211         val->totalhigh = totalhigh_pages;
4212         val->freehigh = nr_free_highpages();
4213         val->mem_unit = PAGE_SIZE;
4214 }
4215 
4216 EXPORT_SYMBOL(si_meminfo);
4217 
4218 #ifdef CONFIG_NUMA
4219 void si_meminfo_node(struct sysinfo *val, int nid)
4220 {
4221         int zone_type;          /* needs to be signed */
4222         unsigned long managed_pages = 0;
4223         unsigned long managed_highpages = 0;
4224         unsigned long free_highpages = 0;
4225         pg_data_t *pgdat = NODE_DATA(nid);
4226 
4227         for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
4228                 managed_pages += pgdat->node_zones[zone_type].managed_pages;
4229         val->totalram = managed_pages;
4230         val->sharedram = node_page_state(pgdat, NR_SHMEM);
4231         val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
4232 #ifdef CONFIG_HIGHMEM
4233         for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
4234                 struct zone *zone = &pgdat->node_zones[zone_type];
4235 
4236                 if (is_highmem(zone)) {
4237                         managed_highpages += zone->managed_pages;
4238                         free_highpages += zone_page_state(zone, NR_FREE_PAGES);
4239                 }
4240         }
4241         val->totalhigh = managed_highpages;
4242         val->freehigh = free_highpages;
4243 #else
4244         val->totalhigh = managed_highpages;
4245         val->freehigh = free_highpages;
4246 #endif
4247         val->mem_unit = PAGE_SIZE;
4248 }
4249 #endif
4250 
4251 /*
4252  * Determine whether the node should be displayed or not, depending on whether
4253  * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
4254  */
4255 bool skip_free_areas_node(unsigned int flags, int nid)
4256 {
4257         bool ret = false;
4258         unsigned int cpuset_mems_cookie;
4259 
4260         if (!(flags & SHOW_MEM_FILTER_NODES))
4261                 goto out;
4262 
4263         do {
4264                 cpuset_mems_cookie = read_mems_allowed_begin();
4265                 ret = !node_isset(nid, cpuset_current_mems_allowed);
4266         } while (read_mems_allowed_retry(cpuset_mems_cookie));
4267 out:
4268         return ret;
4269 }
4270 
4271 #define K(x) ((x) << (PAGE_SHIFT-10))
4272 
4273 static void show_migration_types(unsigned char type)
4274 {
4275         static const char types[MIGRATE_TYPES] = {
4276                 [MIGRATE_UNMOVABLE]     = 'U',
4277                 [MIGRATE_MOVABLE]       = 'M',
4278                 [MIGRATE_RECLAIMABLE]   = 'E',
4279                 [MIGRATE_HIGHATOMIC]    = 'H',
4280 #ifdef CONFIG_CMA
4281                 [MIGRATE_CMA]           = 'C',
4282 #endif
4283 #ifdef CONFIG_MEMORY_ISOLATION
4284                 [MIGRATE_ISOLATE]       = 'I',
4285 #endif
4286         };
4287         char tmp[MIGRATE_TYPES + 1];
4288         char *p = tmp;
4289         int i;
4290 
4291         for (i = 0; i < MIGRATE_TYPES; i++) {
4292                 if (type & (1 << i))
4293                         *p++ = types[i];
4294         }
4295 
4296         *p = '\0';
4297         printk(KERN_CONT "(%s) ", tmp);
4298 }
4299 
4300 /*
4301  * Show free area list (used inside shift_scroll-lock stuff)
4302  * We also calculate the percentage fragmentation. We do this by counting the
4303  * memory on each free list with the exception of the first item on the list.
4304  *
4305  * Bits in @filter:
4306  * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
4307  *   cpuset.
4308  */
4309 void show_free_areas(unsigned int filter)
4310 {
4311         unsigned long free_pcp = 0;
4312         int cpu;
4313         struct zone *zone;
4314         pg_data_t *pgdat;
4315 
4316         for_each_populated_zone(zone) {
4317                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
4318                         continue;
4319 
4320                 for_each_online_cpu(cpu)
4321                         free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
4322         }
4323 
4324         printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
4325                 " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
4326                 " unevictable:%lu dirty:%lu writeback:%lu unstable:%lu\n"
4327                 " slab_reclaimable:%lu slab_unreclaimable:%lu\n"
4328                 " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
4329                 " free:%lu free_pcp:%lu free_cma:%lu\n",
4330                 global_node_page_state(NR_ACTIVE_ANON),
4331                 global_node_page_state(NR_INACTIVE_ANON),
4332                 global_node_page_state(NR_ISOLATED_ANON),
4333                 global_node_page_state(NR_ACTIVE_FILE),
4334                 global_node_page_state(NR_INACTIVE_FILE),
4335                 global_node_page_state(NR_ISOLATED_FILE),
4336                 global_node_page_state(NR_UNEVICTABLE),
4337                 global_node_page_state(NR_FILE_DIRTY),
4338                 global_node_page_state(NR_WRITEBACK),
4339                 global_node_page_state(NR_UNSTABLE_NFS),
4340                 global_page_state(NR_SLAB_RECLAIMABLE),
4341                 global_page_state(NR_SLAB_UNRECLAIMABLE),
4342                 global_node_page_state(NR_FILE_MAPPED),
4343                 global_node_page_state(NR_SHMEM),
4344                 global_page_state(NR_PAGETABLE),
4345                 global_page_state(NR_BOUNCE),
4346                 global_page_state(NR_FREE_PAGES),
4347                 free_pcp,
4348                 global_page_state(NR_FREE_CMA_PAGES));
4349 
4350         for_each_online_pgdat(pgdat) {
4351                 printk("Node %d"
4352                         " active_anon:%lukB"
4353                         " inactive_anon:%lukB"
4354                         " active_file:%lukB"
4355                         " inactive_file:%lukB"
4356                         " unevictable:%lukB"
4357                         " isolated(anon):%lukB"
4358                         " isolated(file):%lukB"
4359                         " mapped:%lukB"
4360                         " dirty:%lukB"
4361                         " writeback:%lukB"
4362                         " shmem:%lukB"
4363 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4364                         " shmem_thp: %lukB"
4365                         " shmem_pmdmapped: %lukB"
4366                         " anon_thp: %lukB"
4367 #endif
4368                         " writeback_tmp:%lukB"
4369                         " unstable:%lukB"
4370                         " pages_scanned:%lu"
4371                         " all_unreclaimable? %s"
4372                         "\n",
4373                         pgdat->node_id,
4374                         K(node_page_state(pgdat, NR_ACTIVE_ANON)),
4375                         K(node_page_state(pgdat, NR_INACTIVE_ANON)),
4376                         K(node_page_state(pgdat, NR_ACTIVE_FILE)),
4377                         K(node_page_state(pgdat, NR_INACTIVE_FILE)),
4378                         K(node_page_state(pgdat, NR_UNEVICTABLE)),
4379                         K(node_page_state(pgdat, NR_ISOLATED_ANON)),
4380                         K(node_page_state(pgdat, NR_ISOLATED_FILE)),
4381                         K(node_page_state(pgdat, NR_FILE_MAPPED)),
4382                         K(node_page_state(pgdat, NR_FILE_DIRTY)),
4383                         K(node_page_state(pgdat, NR_WRITEBACK)),
4384 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4385                         K(node_page_state(pgdat, NR_SHMEM_THPS) * HPAGE_PMD_NR),
4386                         K(node_page_state(pgdat, NR_SHMEM_PMDMAPPED)
4387                                         * HPAGE_PMD_NR),
4388                         K(node_page_state(pgdat, NR_ANON_THPS) * HPAGE_PMD_NR),
4389 #endif
4390                         K(node_page_state(pgdat, NR_SHMEM)),
4391                         K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
4392                         K(node_page_state(pgdat, NR_UNSTABLE_NFS)),
4393                         node_page_state(pgdat, NR_PAGES_SCANNED),
4394                         !pgdat_reclaimable(pgdat) ? "yes" : "no");
4395         }
4396 
4397         for_each_populated_zone(zone) {
4398                 int i;
4399 
4400                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
4401                         continue;
4402 
4403                 free_pcp = 0;
4404                 for_each_online_cpu(cpu)
4405                         free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
4406 
4407                 show_node(zone);
4408                 printk(KERN_CONT
4409                         "%s"
4410                         " free:%lukB"
4411                         " min:%lukB"
4412                         " low:%lukB"
4413                         " high:%lukB"
4414                         " active_anon:%lukB"
4415                         " inactive_anon:%lukB"
4416                         " active_file:%lukB"
4417                         " inactive_file:%lukB"
4418                         " unevictable:%lukB"
4419                         " writepending:%lukB"
4420                         " present:%lukB"
4421                         " managed:%lukB"
4422                         " mlocked:%lukB"
4423                         " slab_reclaimable:%lukB"
4424                         " slab_unreclaimable:%lukB"
4425                         " kernel_stack:%lukB"
4426                         " pagetables:%lukB"
4427                         " bounce:%lukB"
4428                         " free_pcp:%lukB"
4429                         " local_pcp:%ukB"
4430                         " free_cma:%lukB"
4431                         "\n",
4432                         zone->name,
4433                         K(zone_page_state(zone, NR_FREE_PAGES)),
4434                         K(min_wmark_pages(zone)),
4435                         K(low_wmark_pages(zone)),
4436                         K(high_wmark_pages(zone)),
4437                         K(zone_page_state(zone, NR_ZONE_ACTIVE_ANON)),
4438                         K(zone_page_state(zone, NR_ZONE_INACTIVE_ANON)),
4439                         K(zone_page_state(zone, NR_ZONE_ACTIVE_FILE)),
4440                         K(zone_page_state(zone, NR_ZONE_INACTIVE_FILE)),
4441                         K(zone_page_state(zone, NR_ZONE_UNEVICTABLE)),
4442                         K(zone_page_state(zone, NR_ZONE_WRITE_PENDING)),
4443                         K(zone->present_pages),
4444                         K(zone->managed_pages),
4445                         K(zone_page_state(zone, NR_MLOCK)),
4446                         K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
4447                         K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
4448                         zone_page_state(zone, NR_KERNEL_STACK_KB),
4449                         K(zone_page_state(zone, NR_PAGETABLE)),
4450                         K(zone_page_state(zone, NR_BOUNCE)),
4451                         K(free_pcp),
4452                         K(this_cpu_read(zone->pageset->pcp.count)),
4453                         K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
4454                 printk("lowmem_reserve[]:");
4455                 for (i = 0; i < MAX_NR_ZONES; i++)
4456                         printk(KERN_CONT " %ld", zone->lowmem_reserve[i]);
4457                 printk(KERN_CONT "\n");
4458         }
4459 
4460         for_each_populated_zone(zone) {
4461                 unsigned int order;
4462                 unsigned long nr[MAX_ORDER], flags, total = 0;
4463                 unsigned char types[MAX_ORDER];
4464 
4465                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
4466                         continue;
4467                 show_node(zone);
4468                 printk(KERN_CONT "%s: ", zone->name);
4469 
4470                 spin_lock_irqsave(&zone->lock, flags);
4471                 for (order = 0; order < MAX_ORDER; order++) {
4472                         struct free_area *area = &zone->free_area[order];
4473                         int type;
4474 
4475                         nr[order] = area->nr_free;
4476                         total += nr[order] << order;
4477 
4478                         types[order] = 0;
4479                         for (type = 0; type < MIGRATE_TYPES; type++) {
4480                                 if (!list_empty(&area->free_list[type]))
4481                                         types[order] |= 1 << type;
4482                         }
4483                 }
4484                 spin_unlock_irqrestore(&zone->lock, flags);
4485                 for (order = 0; order < MAX_ORDER; order++) {
4486                         printk(KERN_CONT "%lu*%lukB ",
4487                                nr[order], K(1UL) << order);
4488                         if (nr[order])
4489                                 show_migration_types(types[order]);
4490                 }
4491                 printk(KERN_CONT "= %lukB\n", K(total));
4492         }
4493 
4494         hugetlb_show_meminfo();
4495 
4496         printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
4497 
4498         show_swap_cache_info();
4499 }
4500 
4501 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
4502 {
4503         zoneref->zone = zone;
4504         zoneref->zone_idx = zone_idx(zone);
4505 }
4506 
4507 /*
4508  * Builds allocation fallback zone lists.
4509  *
4510  * Add all populated zones of a node to the zonelist.
4511  */
4512 static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
4513                                 int nr_zones)
4514 {
4515         struct zone *zone;
4516         enum zone_type zone_type = MAX_NR_ZONES;
4517 
4518         do {
4519                 zone_type--;
4520                 zone = pgdat->node_zones + zone_type;
4521                 if (managed_zone(zone)) {
4522                         zoneref_set_zone(zone,
4523                                 &zonelist->_zonerefs[nr_zones++]);
4524                         check_highest_zone(zone_type);
4525                 }
4526         } while (zone_type);
4527 
4528         return nr_zones;
4529 }
4530 
4531 
4532 /*
4533  *  zonelist_order:
4534  *  0 = automatic detection of better ordering.
4535  *  1 = order by ([node] distance, -zonetype)
4536  *  2 = order by (-zonetype, [node] distance)
4537  *
4538  *  If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
4539  *  the same zonelist. So only NUMA can configure this param.
4540  */
4541 #define ZONELIST_ORDER_DEFAULT  0
4542 #define ZONELIST_ORDER_NODE     1
4543 #define ZONELIST_ORDER_ZONE     2
4544 
4545 /* zonelist order in the kernel.
4546  * set_zonelist_order() will set this to NODE or ZONE.
4547  */
4548 static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
4549 static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
4550 
4551 
4552 #ifdef CONFIG_NUMA
4553 /* The value user specified ....changed by config */
4554 static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
4555 /* string for sysctl */
4556 #define NUMA_ZONELIST_ORDER_LEN 16
4557 char numa_zonelist_order[16] = "default";
4558 
4559 /*
4560  * interface for configure zonelist ordering.
4561  * command line option "numa_zonelist_order"
4562  *      = "[dD]efault   - default, automatic configuration.
4563  *      = "[nN]ode      - order by node locality, then by zone within node
4564  *      = "[zZ]one      - order by zone, then by locality within zone
4565  */
4566 
4567 static int __parse_numa_zonelist_order(char *s)
4568 {
4569         if (*s == 'd' || *s == 'D') {
4570                 user_zonelist_order = ZONELIST_ORDER_DEFAULT;
4571         } else if (*s == 'n' || *s == 'N') {
4572                 user_zonelist_order = ZONELIST_ORDER_NODE;
4573         } else if (*s == 'z' || *s == 'Z') {
4574                 user_zonelist_order = ZONELIST_ORDER_ZONE;
4575         } else {
4576                 pr_warn("Ignoring invalid numa_zonelist_order value:  %s\n", s);
4577                 return -EINVAL;
4578         }
4579         return 0;
4580 }
4581 
4582 static __init int setup_numa_zonelist_order(char *s)
4583 {
4584         int ret;
4585 
4586         if (!s)
4587                 return 0;
4588 
4589         ret = __parse_numa_zonelist_order(s);
4590         if (ret == 0)
4591                 strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
4592 
4593         return ret;
4594 }
4595 early_param("numa_zonelist_order", setup_numa_zonelist_order);
4596 
4597 /*
4598  * sysctl handler for numa_zonelist_order
4599  */
4600 int numa_zonelist_order_handler(struct ctl_table *table, int write,
4601                 void __user *buffer, size_t *length,
4602                 loff_t *ppos)
4603 {
4604         char saved_string[NUMA_ZONELIST_ORDER_LEN];
4605         int ret;
4606         static DEFINE_MUTEX(zl_order_mutex);
4607 
4608         mutex_lock(&zl_order_mutex);
4609         if (write) {
4610                 if (strlen((char *)table->data) >= NUMA_ZONELIST_ORDER_LEN) {
4611                         ret = -EINVAL;
4612                         goto out;
4613                 }
4614                 strcpy(saved_string, (char *)table->data);
4615         }
4616         ret = proc_dostring(table, write, buffer, length, ppos);
4617         if (ret)
4618                 goto out;
4619         if (write) {
4620                 int oldval = user_zonelist_order;
4621 
4622                 ret = __parse_numa_zonelist_order((char *)table->data);
4623                 if (ret) {
4624                         /*
4625                          * bogus value.  restore saved string
4626                          */
4627                         strncpy((char *)table->data, saved_string,
4628                                 NUMA_ZONELIST_ORDER_LEN);
4629                         user_zonelist_order = oldval;
4630                 } else if (oldval != user_zonelist_order) {
4631                         mutex_lock(&zonelists_mutex);
4632                         build_all_zonelists(NULL, NULL);
4633                         mutex_unlock(&zonelists_mutex);
4634                 }
4635         }
4636 out:
4637         mutex_unlock(&zl_order_mutex);
4638         return ret;
4639 }
4640 
4641 
4642 #define MAX_NODE_LOAD (nr_online_nodes)
4643 static int node_load[MAX_NUMNODES];
4644 
4645 /**
4646  * find_next_best_node - find the next node that should appear in a given node's fallback list
4647  * @node: node whose fallback list we're appending
4648  * @used_node_mask: nodemask_t of already used nodes
4649  *
4650  * We use a number of factors to determine which is the next node that should
4651  * appear on a given node's fallback list.  The node should not have appeared
4652  * already in @node's fallback list, and it should be the next closest node
4653  * according to the distance array (which contains arbitrary distance values
4654  * from each node to each node in the system), and should also prefer nodes
4655  * with no CPUs, since presumably they'll have very little allocation pressure
4656  * on them otherwise.
4657  * It returns -1 if no node is found.
4658  */
4659 static int find_next_best_node(int node, nodemask_t *used_node_mask)
4660 {
4661         int n, val;
4662         int min_val = INT_MAX;
4663         int best_node = NUMA_NO_NODE;
4664         const struct cpumask *tmp = cpumask_of_node(0);
4665 
4666         /* Use the local node if we haven't already */
4667         if (!node_isset(node, *used_node_mask)) {
4668                 node_set(node, *used_node_mask);
4669                 return node;
4670         }
4671 
4672         for_each_node_state(n, N_MEMORY) {
4673 
4674                 /* Don't want a node to appear more than once */
4675                 if (node_isset(n, *used_node_mask))
4676                         continue;
4677 
4678                 /* Use the distance array to find the distance */
4679                 val = node_distance(node, n);
4680 
4681                 /* Penalize nodes under us ("prefer the next node") */
4682                 val += (n < node);
4683 
4684                 /* Give preference to headless and unused nodes */
4685                 tmp = cpumask_of_node(n);
4686                 if (!cpumask_empty(tmp))
4687                         val += PENALTY_FOR_NODE_WITH_CPUS;
4688 
4689                 /* Slight preference for less loaded node */
4690                 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
4691                 val += node_load[n];
4692 
4693                 if (val < min_val) {
4694                         min_val = val;
4695                         best_node = n;
4696                 }
4697         }
4698 
4699         if (best_node >= 0)
4700                 node_set(best_node, *used_node_mask);
4701 
4702         return best_node;
4703 }
4704 
4705 
4706 /*
4707  * Build zonelists ordered by node and zones within node.
4708  * This results in maximum locality--normal zone overflows into local
4709  * DMA zone, if any--but risks exhausting DMA zone.
4710  */
4711 static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
4712 {
4713         int j;
4714         struct zonelist *zonelist;
4715 
4716         zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK];
4717         for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
4718                 ;
4719         j = build_zonelists_node(NODE_DATA(node), zonelist, j);
4720         zonelist->_zonerefs[j].zone = NULL;
4721         zonelist->_zonerefs[j].zone_idx = 0;
4722 }
4723 
4724 /*
4725  * Build gfp_thisnode zonelists
4726  */
4727 static void build_thisnode_zonelists(pg_data_t *pgdat)
4728 {
4729         int j;
4730         struct zonelist *zonelist;
4731 
4732         zonelist = &pgdat->node_zonelists[ZONELIST_NOFALLBACK];
4733         j = build_zonelists_node(pgdat, zonelist, 0);
4734         zonelist->_zonerefs[j].zone = NULL;
4735         zonelist->_zonerefs[j].zone_idx = 0;
4736 }
4737 
4738 /*
4739  * Build zonelists ordered by zone and nodes within zones.
4740  * This results in conserving DMA zone[s] until all Normal memory is
4741  * exhausted, but results in overflowing to remote node while memory
4742  * may still exist in local DMA zone.
4743  */
4744 static int node_order[MAX_NUMNODES];
4745 
4746 static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
4747 {
4748         int pos, j, node;
4749         int zone_type;          /* needs to be signed */
4750         struct zone *z;
4751         struct zonelist *zonelist;
4752 
4753         zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK];
4754         pos = 0;
4755         for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
4756                 for (j = 0; j < nr_nodes; j++) {
4757                         node = node_order[j];
4758                         z = &NODE_DATA(node)->node_zones[zone_type];
4759                         if (managed_zone(z)) {
4760                                 zoneref_set_zone(z,
4761                                         &zonelist->_zonerefs[pos++]);
4762                                 check_highest_zone(zone_type);
4763                         }
4764                 }
4765         }
4766         zonelist->_zonerefs[pos].zone = NULL;
4767         zonelist->_zonerefs[pos].zone_idx = 0;
4768 }
4769 
4770 #if defined(CONFIG_64BIT)
4771 /*
4772  * Devices that require DMA32/DMA are relatively rare and do not justify a
4773  * penalty to every machine in case the specialised case applies. Default
4774  * to Node-ordering on 64-bit NUMA machines
4775  */
4776 static int default_zonelist_order(void)
4777 {
4778         return ZONELIST_ORDER_NODE;
4779 }
4780 #else
4781 /*
4782  * On 32-bit, the Normal zone needs to be preserved for allocations accessible
4783  * by the kernel. If processes running on node 0 deplete the low memory zone
4784  * then reclaim will occur more frequency increasing stalls and potentially
4785  * be easier to OOM if a large percentage of the zone is under writeback or
4786  * dirty. The problem is significantly worse if CONFIG_HIGHPTE is not set.
4787  * Hence, default to zone ordering on 32-bit.
4788  */
4789 static int default_zonelist_order(void)
4790 {
4791         return ZONELIST_ORDER_ZONE;
4792 }
4793 #endif /* CONFIG_64BIT */
4794 
4795 static void set_zonelist_order(void)
4796 {
4797         if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
4798                 current_zonelist_order = default_zonelist_order();
4799         else
4800                 current_zonelist_order = user_zonelist_order;
4801 }
4802 
4803 static void build_zonelists(pg_data_t *pgdat)
4804 {
4805         int i, node, load;
4806         nodemask_t used_mask;
4807         int local_node, prev_node;
4808         struct zonelist *zonelist;
4809         unsigned int order = current_zonelist_order;
4810 
4811         /* initialize zonelists */
4812         for (i = 0; i < MAX_ZONELISTS; i++) {
4813                 zonelist = pgdat->node_zonelists + i;
4814                 zonelist->_zonerefs[0].zone = NULL;
4815                 zonelist->_zonerefs[0].zone_idx = 0;
4816         }
4817 
4818         /* NUMA-aware ordering of nodes */
4819         local_node = pgdat->node_id;
4820         load = nr_online_nodes;
4821         prev_node = local_node;
4822         nodes_clear(used_mask);
4823 
4824         memset(node_order, 0, sizeof(node_order));
4825         i = 0;
4826 
4827         while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
4828                 /*
4829                  * We don't want to pressure a particular node.
4830                  * So adding penalty to the first node in same
4831                  * distance group to make it round-robin.
4832                  */
4833                 if (node_distance(local_node, node) !=
4834                     node_distance(local_node, prev_node))
4835                         node_load[node] = load;
4836 
4837                 prev_node = node;
4838                 load--;
4839                 if (order == ZONELIST_ORDER_NODE)
4840                         build_zonelists_in_node_order(pgdat, node);
4841                 else
4842                         node_order[i++] = node; /* remember order */
4843         }
4844 
4845         if (order == ZONELIST_ORDER_ZONE) {
4846                 /* calculate node order -- i.e., DMA last! */
4847                 build_zonelists_in_zone_order(pgdat, i);
4848         }
4849 
4850         build_thisnode_zonelists(pgdat);
4851 }
4852 
4853 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
4854 /*
4855  * Return node id of node used for "local" allocations.
4856  * I.e., first node id of first zone in arg node's generic zonelist.
4857  * Used for initializing percpu 'numa_mem', which is used primarily
4858  * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
4859  */
4860 int local_memory_node(int node)
4861 {
4862         struct zoneref *z;
4863 
4864         z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
4865                                    gfp_zone(GFP_KERNEL),
4866                                    NULL);
4867         return z->zone->node;
4868 }
4869 #endif
4870 
4871 static void setup_min_unmapped_ratio(void);
4872 static void setup_min_slab_ratio(void);
4873 #else   /* CONFIG_NUMA */
4874 
4875 static void set_zonelist_order(void)
4876 {
4877         current_zonelist_order = ZONELIST_ORDER_ZONE;
4878 }
4879 
4880 static void build_zonelists(pg_data_t *pgdat)
4881 {
4882         int node, local_node;
4883         enum zone_type j;
4884         struct zonelist *zonelist;
4885 
4886         local_node = pgdat->node_id;
4887 
4888         zonelist = &pgdat->node_zonelists[ZONELIST_FALLBACK];
4889         j = build_zonelists_node(pgdat, zonelist, 0);
4890 
4891         /*
4892          * Now we build the zonelist so that it contains the zones
4893          * of all the other nodes.
4894          * We don't want to pressure a particular node, so when
4895          * building the zones for node N, we make sure that the
4896          * zones coming right after the local ones are those from
4897          * node N+1 (modulo N)
4898          */
4899         for (node = local_node + 1; node < MAX_NUMNODES; node++) {
4900                 if (!node_online(node))
4901                         continue;
4902                 j = build_zonelists_node(NODE_DATA(node), zonelist, j);
4903         }
4904         for (node = 0; node < local_node; node++) {
4905                 if (!node_online(node))
4906                         continue;
4907                 j = build_zonelists_node(NODE_DATA(node), zonelist, j);
4908         }
4909 
4910         zonelist->_zonerefs[j].zone = NULL;
4911         zonelist->_zonerefs[j].zone_idx = 0;
4912 }
4913 
4914 #endif  /* CONFIG_NUMA */
4915 
4916 /*
4917  * Boot pageset table. One per cpu which is going to be used for all
4918  * zones and all nodes. The parameters will be set in such a way
4919  * that an item put on a list will immediately be handed over to
4920  * the buddy list. This is safe since pageset manipulation is done
4921  * with interrupts disabled.
4922  *
4923  * The boot_pagesets must be kept even after bootup is complete for
4924  * unused processors and/or zones. They do play a role for bootstrapping
4925  * hotplugged processors.
4926  *
4927  * zoneinfo_show() and maybe other functions do
4928  * not check if the processor is online before following the pageset pointer.
4929  * Other parts of the kernel may not check if the zone is available.
4930  */
4931 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
4932 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
4933 static void setup_zone_pageset(struct zone *zone);
4934 
4935 /*
4936  * Global mutex to protect against size modification of zonelists
4937  * as well as to serialize pageset setup for the new populated zone.
4938  */
4939 DEFINE_MUTEX(zonelists_mutex);
4940 
4941 /* return values int ....just for stop_machine() */
4942 static int __build_all_zonelists(void *data)
4943 {
4944         int nid;
4945         int cpu;
4946         pg_data_t *self = data;
4947 
4948 #ifdef CONFIG_NUMA
4949         memset(node_load, 0, sizeof(node_load));
4950 #endif
4951 
4952         if (self && !node_online(self->node_id)) {
4953                 build_zonelists(self);
4954         }
4955 
4956         for_each_online_node(nid) {
4957                 pg_data_t *pgdat = NODE_DATA(nid);
4958 
4959                 build_zonelists(pgdat);
4960         }
4961 
4962         /*
4963          * Initialize the boot_pagesets that are going to be used
4964          * for bootstrapping processors. The real pagesets for
4965          * each zone will be allocated later when the per cpu
4966          * allocator is available.
4967          *
4968          * boot_pagesets are used also for bootstrapping offline
4969          * cpus if the system is already booted because the pagesets
4970          * are needed to initialize allocators on a specific cpu too.
4971          * F.e. the percpu allocator needs the page allocator which
4972          * needs the percpu allocator in order to allocate its pagesets
4973          * (a chicken-egg dilemma).
4974          */
4975         for_each_possible_cpu(cpu) {
4976                 setup_pageset(&per_cpu(boot_pageset, cpu), 0);
4977 
4978 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
4979                 /*
4980                  * We now know the "local memory node" for each node--
4981                  * i.e., the node of the first zone in the generic zonelist.
4982                  * Set up numa_mem percpu variable for on-line cpus.  During
4983                  * boot, only the boot cpu should be on-line;  we'll init the
4984                  * secondary cpus' numa_mem as they come on-line.  During
4985                  * node/memory hotplug, we'll fixup all on-line cpus.
4986                  */
4987                 if (cpu_online(cpu))
4988                         set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
4989 #endif
4990         }
4991 
4992         return 0;
4993 }
4994 
4995 static noinline void __init
4996 build_all_zonelists_init(void)
4997 {
4998         __build_all_zonelists(NULL);
4999         mminit_verify_zonelist();
5000         cpuset_init_current_mems_allowed();
5001 }
5002 
5003 /*
5004  * Called with zonelists_mutex held always
5005  * unless system_state == SYSTEM_BOOTING.
5006  *
5007  * __ref due to (1) call of __meminit annotated setup_zone_pageset
5008  * [we're only called with non-NULL zone through __meminit paths] and
5009  * (2) call of __init annotated helper build_all_zonelists_init
5010  * [protected by SYSTEM_BOOTING].
5011  */
5012 void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone)
5013 {
5014         set_zonelist_order();
5015 
5016         if (system_state == SYSTEM_BOOTING) {
5017                 build_all_zonelists_init();
5018         } else {
5019 #ifdef CONFIG_MEMORY_HOTPLUG
5020                 if (zone)
5021                         setup_zone_pageset(zone);
5022 #endif
5023                 /* we have to stop all cpus to guarantee there is no user
5024                    of zonelist */
5025                 stop_machine(__build_all_zonelists, pgdat, NULL);
5026                 /* cpuset refresh routine should be here */
5027         }
5028         vm_total_pages = nr_free_pagecache_pages();
5029         /*
5030          * Disable grouping by mobility if the number of pages in the
5031          * system is too low to allow the mechanism to work. It would be
5032          * more accurate, but expensive to check per-zone. This check is
5033          * made on memory-hotadd so a system can start with mobility
5034          * disabled and enable it later
5035          */
5036         if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
5037                 page_group_by_mobility_disabled = 1;
5038         else
5039                 page_group_by_mobility_disabled = 0;
5040 
5041         pr_info("Built %i zonelists in %s order, mobility grouping %s.  Total pages: %ld\n",
5042                 nr_online_nodes,
5043                 zonelist_order_name[current_zonelist_order],
5044                 page_group_by_mobility_disabled ? "off" : "on",
5045                 vm_total_pages);
5046 #ifdef CONFIG_NUMA
5047         pr_info("Policy zone: %s\n", zone_names[policy_zone]);
5048 #endif
5049 }
5050 
5051 /*
5052  * Initially all pages are reserved - free ones are freed
5053  * up by free_all_bootmem() once the early boot process is
5054  * done. Non-atomic initialization, single-pass.
5055  */
5056 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
5057                 unsigned long start_pfn, enum memmap_context context)
5058 {
5059         struct vmem_altmap *altmap = to_vmem_altmap(__pfn_to_phys(start_pfn));
5060         unsigned long end_pfn = start_pfn + size;
5061         pg_data_t *pgdat = NODE_DATA(nid);
5062         unsigned long pfn;
5063         unsigned long nr_initialised = 0;
5064 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5065         struct memblock_region *r = NULL, *tmp;
5066 #endif
5067 
5068         if (highest_memmap_pfn < end_pfn - 1)
5069                 highest_memmap_pfn = end_pfn - 1;
5070 
5071         /*
5072          * Honor reservation requested by the driver for this ZONE_DEVICE
5073          * memory
5074          */
5075         if (altmap && start_pfn == altmap->base_pfn)
5076                 start_pfn += altmap->reserve;
5077 
5078         for (pfn = start_pfn; pfn < end_pfn; pfn++) {
5079                 /*
5080                  * There can be holes in boot-time mem_map[]s handed to this
5081                  * function.  They do not exist on hotplugged memory.
5082                  */
5083                 if (context != MEMMAP_EARLY)
5084                         goto not_early;
5085 
5086                 if (!early_pfn_valid(pfn))
5087                         continue;
5088                 if (!early_pfn_in_nid(pfn, nid))
5089                         continue;
5090                 if (!update_defer_init(pgdat, pfn, end_pfn, &nr_initialised))
5091                         break;
5092 
5093 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5094                 /*
5095                  * Check given memblock attribute by firmware which can affect
5096                  * kernel memory layout.  If zone==ZONE_MOVABLE but memory is
5097                  * mirrored, it's an overlapped memmap init. skip it.
5098                  */
5099                 if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
5100                         if (!r || pfn >= memblock_region_memory_end_pfn(r)) {
5101                                 for_each_memblock(memory, tmp)
5102                                         if (pfn < memblock_region_memory_end_pfn(tmp))
5103                                                 break;
5104                                 r = tmp;
5105                         }
5106                         if (pfn >= memblock_region_memory_base_pfn(r) &&
5107                             memblock_is_mirror(r)) {
5108                                 /* already initialized as NORMAL */
5109                                 pfn = memblock_region_memory_end_pfn(r);
5110                                 continue;
5111                         }
5112                 }
5113 #endif
5114 
5115 not_early:
5116                 /*
5117                  * Mark the block movable so that blocks are reserved for
5118                  * movable at startup. This will force kernel allocations
5119                  * to reserve their blocks rather than leaking throughout
5120                  * the address space during boot when many long-lived
5121                  * kernel allocations are made.
5122                  *
5123                  * bitmap is created for zone's valid pfn range. but memmap
5124                  * can be created for invalid pages (for alignment)
5125                  * check here not to call set_pageblock_migratetype() against
5126                  * pfn out of zone.
5127                  */
5128                 if (!(pfn & (pageblock_nr_pages - 1))) {
5129                         struct page *page = pfn_to_page(pfn);
5130 
5131                         __init_single_page(page, pfn, zone, nid);
5132                         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5133                 } else {
5134                         __init_single_pfn(pfn, zone, nid);
5135                 }
5136         }
5137 }
5138 
5139 static void __meminit zone_init_free_lists(struct zone *zone)
5140 {
5141         unsigned int order, t;
5142         for_each_migratetype_order(order, t) {
5143                 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
5144                 zone->free_area[order].nr_free = 0;
5145         }
5146 }
5147 
5148 #ifndef __HAVE_ARCH_MEMMAP_INIT
5149 #define memmap_init(size, nid, zone, start_pfn) \
5150         memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
5151 #endif
5152 
5153 static int zone_batchsize(struct zone *zone)
5154 {
5155 #ifdef CONFIG_MMU
5156         int batch;
5157 
5158         /*
5159          * The per-cpu-pages pools are set to around 1000th of the
5160          * size of the zone.  But no more than 1/2 of a meg.
5161          *
5162          * OK, so we don't know how big the cache is.  So guess.
5163          */
5164         batch = zone->managed_pages / 1024;
5165         if (batch * PAGE_SIZE > 512 * 1024)
5166                 batch = (512 * 1024) / PAGE_SIZE;
5167         batch /= 4;             /* We effectively *= 4 below */
5168         if (batch < 1)
5169                 batch = 1;
5170 
5171         /*
5172          * Clamp the batch to a 2^n - 1 value. Having a power
5173          * of 2 value was found to be more likely to have
5174          * suboptimal cache aliasing properties in some cases.
5175          *
5176          * For example if 2 tasks are alternately allocating
5177          * batches of pages, one task can end up with a lot
5178          * of pages of one half of the possible page colors
5179          * and the other with pages of the other colors.
5180          */
5181         batch = rounddown_pow_of_two(batch + batch/2) - 1;
5182 
5183         return batch;
5184 
5185 #else
5186         /* The deferral and batching of frees should be suppressed under NOMMU
5187          * conditions.
5188          *
5189          * The problem is that NOMMU needs to be able to allocate large chunks
5190          * of contiguous memory as there's no hardware page translation to
5191          * assemble apparent contiguous memory from discontiguous pages.
5192          *
5193          * Queueing large contiguous runs of pages for batching, however,
5194          * causes the pages to actually be freed in smaller chunks.  As there
5195          * can be a significant delay between the individual batches being
5196          * recycled, this leads to the once large chunks of space being
5197          * fragmented and becoming unavailable for high-order allocations.
5198          */
5199         return 0;
5200 #endif
5201 }
5202 
5203 /*
5204  * pcp->high and pcp->batch values are related and dependent on one another:
5205  * ->batch must never be higher then ->high.
5206  * The following function updates them in a safe manner without read side
5207  * locking.
5208  *
5209  * Any new users of pcp->batch and pcp->high should ensure they can cope with
5210  * those fields changing asynchronously (acording the the above rule).
5211  *
5212  * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
5213  * outside of boot time (or some other assurance that no concurrent updaters
5214  * exist).
5215  */
5216 static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
5217                 unsigned long batch)
5218 {
5219        /* start with a fail safe value for batch */
5220         pcp->batch = 1;
5221         smp_wmb();
5222 
5223        /* Update high, then batch, in order */
5224         pcp->high = high;
5225         smp_wmb();
5226 
5227         pcp->batch = batch;
5228 }
5229 
5230 /* a companion to pageset_set_high() */
5231 static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
5232 {
5233         pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
5234 }
5235 
5236 static void pageset_init(struct per_cpu_pageset *p)
5237 {
5238         struct per_cpu_pages *pcp;
5239         int migratetype;
5240 
5241         memset(p, 0, sizeof(*p));
5242 
5243         pcp = &p->pcp;
5244         pcp->count = 0;
5245         for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
5246                 INIT_LIST_HEAD(&pcp->lists[migratetype]);
5247 }
5248 
5249 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
5250 {
5251         pageset_init(p);
5252         pageset_set_batch(p, batch);
5253 }
5254 
5255 /*
5256  * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
5257  * to the value high for the pageset p.
5258  */
5259 static void pageset_set_high(struct per_cpu_pageset *p,
5260                                 unsigned long high)
5261 {
5262         unsigned long batch = max(1UL, high / 4);
5263         if ((high / 4) > (PAGE_SHIFT * 8))
5264                 batch = PAGE_SHIFT * 8;
5265 
5266         pageset_update(&p->pcp, high, batch);
5267 }
5268 
5269 static void pageset_set_high_and_batch(struct zone *zone,
5270                                        struct per_cpu_pageset *pcp)
5271 {
5272         if (percpu_pagelist_fraction)
5273                 pageset_set_high(pcp,
5274                         (zone->managed_pages /
5275                                 percpu_pagelist_fraction));
5276         else
5277                 pageset_set_batch(pcp, zone_batchsize(zone));
5278 }
5279 
5280 static void __meminit zone_pageset_init(struct zone *zone, int cpu)
5281 {
5282         struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
5283 
5284         pageset_init(pcp);
5285         pageset_set_high_and_batch(zone, pcp);
5286 }
5287 
5288 static void __meminit setup_zone_pageset(struct zone *zone)
5289 {
5290         int cpu;
5291         zone->pageset = alloc_percpu(struct per_cpu_pageset);
5292         for_each_possible_cpu(cpu)
5293                 zone_pageset_init(zone, cpu);
5294 }
5295 
5296 /*
5297  * Allocate per cpu pagesets and initialize them.
5298  * Before this call only boot pagesets were available.
5299  */
5300 void __init setup_per_cpu_pageset(void)
5301 {
5302         struct pglist_data *pgdat;
5303         struct zone *zone;
5304 
5305         for_each_populated_zone(zone)
5306                 setup_zone_pageset(zone);
5307 
5308         for_each_online_pgdat(pgdat)
5309                 pgdat->per_cpu_nodestats =
5310                         alloc_percpu(struct per_cpu_nodestat);
5311 }
5312 
5313 static __meminit void zone_pcp_init(struct zone *zone)
5314 {
5315         /*
5316          * per cpu subsystem is not up at this point. The following code
5317          * relies on the ability of the linker to provide the
5318          * offset of a (static) per cpu variable into the per cpu area.
5319          */
5320         zone->pageset = &boot_pageset;
5321 
5322         if (populated_zone(zone))
5323                 printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%u\n",
5324                         zone->name, zone->present_pages,
5325                                          zone_batchsize(zone));
5326 }
5327 
5328 int __meminit init_currently_empty_zone(struct zone *zone,
5329                                         unsigned long zone_start_pfn,
5330                                         unsigned long size)
5331 {
5332         struct pglist_data *pgdat = zone->zone_pgdat;
5333 
5334         pgdat->nr_zones = zone_idx(zone) + 1;
5335 
5336         zone->zone_start_pfn = zone_start_pfn;
5337 
5338         mminit_dprintk(MMINIT_TRACE, "memmap_init",
5339                         "Initialising map node %d zone %lu pfns %lu -> %lu\n",
5340                         pgdat->node_id,
5341                         (unsigned long)zone_idx(zone),
5342                         zone_start_pfn, (zone_start_pfn + size));
5343 
5344         zone_init_free_lists(zone);
5345         zone->initialized = 1;
5346 
5347         return 0;
5348 }
5349 
5350 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5351 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
5352 
5353 /*
5354  * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
5355  */
5356 int __meminit __early_pfn_to_nid(unsigned long pfn,
5357                                         struct mminit_pfnnid_cache *state)
5358 {
5359         unsigned long start_pfn, end_pfn;
5360         int nid;
5361 
5362         if (state->last_start <= pfn && pfn < state->last_end)
5363                 return state->last_nid;
5364 
5365         nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
5366         if (nid != -1) {
5367                 state->last_start = start_pfn;
5368                 state->last_end = end_pfn;
5369                 state->last_nid = nid;
5370         }
5371 
5372         return nid;
5373 }
5374 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
5375 
5376 /**
5377  * free_bootmem_with_active_regions - Call memblock_free_early_nid for each active range
5378  * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
5379  * @max_low_pfn: The highest PFN that will be passed to memblock_free_early_nid
5380  *
5381  * If an architecture guarantees that all ranges registered contain no holes
5382  * and may be freed, this this function may be used instead of calling
5383  * memblock_free_early_nid() manually.
5384  */
5385 void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
5386 {
5387         unsigned long start_pfn, end_pfn;
5388         int i, this_nid;
5389 
5390         for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
5391                 start_pfn = min(start_pfn, max_low_pfn);
5392                 end_pfn = min(end_pfn, max_low_pfn);
5393 
5394                 if (start_pfn < end_pfn)
5395                         memblock_free_early_nid(PFN_PHYS(start_pfn),
5396                                         (end_pfn - start_pfn) << PAGE_SHIFT,
5397                                         this_nid);
5398         }
5399 }
5400 
5401 /**
5402  * sparse_memory_present_with_active_regions - Call memory_present for each active range
5403  * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
5404  *
5405  * If an architecture guarantees that all ranges registered contain no holes and may
5406  * be freed, this function may be used instead of calling memory_present() manually.
5407  */
5408 void __init sparse_memory_present_with_active_regions(int nid)
5409 {
5410         unsigned long start_pfn, end_pfn;
5411         int i, this_nid;
5412 
5413         for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
5414                 memory_present(this_nid, start_pfn, end_pfn);
5415 }
5416 
5417 /**
5418  * get_pfn_range_for_nid - Return the start and end page frames for a node
5419  * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
5420  * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
5421  * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
5422  *
5423  * It returns the start and end page frame of a node based on information
5424  * provided by memblock_set_node(). If called for a node
5425  * with no available memory, a warning is printed and the start and end
5426  * PFNs will be 0.
5427  */
5428 void __meminit get_pfn_range_for_nid(unsigned int nid,
5429                         unsigned long *start_pfn, unsigned long *end_pfn)
5430 {
5431         unsigned long this_start_pfn, this_end_pfn;
5432         int i;
5433 
5434         *start_pfn = -1UL;
5435         *end_pfn = 0;
5436 
5437         for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
5438                 *start_pfn = min(*start_pfn, this_start_pfn);
5439                 *end_pfn = max(*end_pfn, this_end_pfn);
5440         }
5441 
5442         if (*start_pfn == -1UL)
5443                 *start_pfn = 0;
5444 }
5445 
5446 /*
5447  * This finds a zone that can be used for ZONE_MOVABLE pages. The
5448  * assumption is made that zones within a node are ordered in monotonic
5449  * increasing memory addresses so that the "highest" populated zone is used
5450  */
5451 static void __init find_usable_zone_for_movable(void)
5452 {
5453         int zone_index;
5454         for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
5455                 if (zone_index == ZONE_MOVABLE)
5456                         continue;
5457 
5458                 if (arch_zone_highest_possible_pfn[zone_index] >
5459                                 arch_zone_lowest_possible_pfn[zone_index])
5460                         break;
5461         }
5462 
5463         VM_BUG_ON(zone_index == -1);
5464         movable_zone = zone_index;
5465 }
5466 
5467 /*
5468  * The zone ranges provided by the architecture do not include ZONE_MOVABLE
5469  * because it is sized independent of architecture. Unlike the other zones,
5470  * the starting point for ZONE_MOVABLE is not fixed. It may be different
5471  * in each node depending on the size of each node and how evenly kernelcore
5472  * is distributed. This helper function adjusts the zone ranges
5473  * provided by the architecture for a given node by using the end of the
5474  * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
5475  * zones within a node are in order of monotonic increases memory addresses
5476  */
5477 static void __meminit adjust_zone_range_for_zone_movable(int nid,
5478                                         unsigned long zone_type,
5479                                         unsigned long node_start_pfn,
5480                                         unsigned long node_end_pfn,
5481                                         unsigned long *zone_start_pfn,
5482                                         unsigned long *zone_end_pfn)
5483 {
5484         /* Only adjust if ZONE_MOVABLE is on this node */
5485         if (zone_movable_pfn[nid]) {
5486                 /* Size ZONE_MOVABLE */
5487                 if (zone_type == ZONE_MOVABLE) {
5488                         *zone_start_pfn = zone_movable_pfn[nid];
5489                         *zone_end_pfn = min(node_end_pfn,
5490                                 arch_zone_highest_possible_pfn[movable_zone]);
5491 
5492                 /* Adjust for ZONE_MOVABLE starting within this range */
5493                 } else if (!mirrored_kernelcore &&
5494                         *zone_start_pfn < zone_movable_pfn[nid] &&
5495                         *zone_end_pfn > zone_movable_pfn[nid]) {
5496                         *zone_end_pfn = zone_movable_pfn[nid];
5497 
5498                 /* Check if this whole range is within ZONE_MOVABLE */
5499                 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
5500                         *zone_start_pfn = *zone_end_pfn;
5501         }
5502 }
5503 
5504 /*
5505  * Return the number of pages a zone spans in a node, including holes
5506  * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
5507  */
5508 static unsigned long __meminit zone_spanned_pages_in_node(int nid,
5509                                         unsigned long zone_type,
5510                                         unsigned long node_start_pfn,
5511                                         unsigned long node_end_pfn,
5512                                         unsigned long *zone_start_pfn,
5513                                         unsigned long *zone_end_pfn,
5514                                         unsigned long *ignored)
5515 {
5516         /* When hotadd a new node from cpu_up(), the node should be empty */
5517         if (!node_start_pfn && !node_end_pfn)
5518                 return 0;
5519 
5520         /* Get the start and end of the zone */
5521         *zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
5522         *zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
5523         adjust_zone_range_for_zone_movable(nid, zone_type,
5524                                 node_start_pfn, node_end_pfn,
5525                                 zone_start_pfn, zone_end_pfn);
5526 
5527         /* Check that this node has pages within the zone's required range */
5528         if (*zone_end_pfn < node_start_pfn || *zone_start_pfn > node_end_pfn)
5529                 return 0;
5530 
5531         /* Move the zone boundaries inside the node if necessary */
5532         *zone_end_pfn = min(*zone_end_pfn, node_end_pfn);
5533         *zone_start_pfn = max(*zone_start_pfn, node_start_pfn);
5534 
5535         /* Return the spanned pages */
5536         return *zone_end_pfn - *zone_start_pfn;
5537 }
5538 
5539 /*
5540  * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
5541  * then all holes in the requested range will be accounted for.
5542  */
5543 unsigned long __meminit __absent_pages_in_range(int nid,
5544                                 unsigned long range_start_pfn,
5545                                 unsigned long range_end_pfn)
5546 {
5547         unsigned long nr_absent = range_end_pfn - range_start_pfn;
5548         unsigned long start_pfn, end_pfn;
5549         int i;
5550 
5551         for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
5552                 start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
5553                 end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
5554                 nr_absent -= end_pfn - start_pfn;
5555         }
5556         return nr_absent;
5557 }
5558 
5559 /**
5560  * absent_pages_in_range - Return number of page frames in holes within a range
5561  * @start_pfn: The start PFN to start searching for holes
5562  * @end_pfn: The end PFN to stop searching for holes
5563  *
5564  * It returns the number of pages frames in memory holes within a range.
5565  */
5566 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
5567                                                         unsigned long end_pfn)
5568 {
5569         return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
5570 }
5571 
5572 /* Return the number of page frames in holes in a zone on a node */
5573 static unsigned long __meminit zone_absent_pages_in_node(int nid,
5574                                         unsigned long zone_type,
5575                                         unsigned long node_start_pfn,
5576                                         unsigned long node_end_pfn,
5577                                         unsigned long *ignored)
5578 {
5579         unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
5580         unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
5581         unsigned long zone_start_pfn, zone_end_pfn;
5582         unsigned long nr_absent;
5583 
5584         /* When hotadd a new node from cpu_up(), the node should be empty */
5585         if (!node_start_pfn && !node_end_pfn)
5586                 return 0;
5587 
5588         zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
5589         zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
5590 
5591         adjust_zone_range_for_zone_movable(nid, zone_type,
5592                         node_start_pfn, node_end_pfn,
5593                         &zone_start_pfn, &zone_end_pfn);
5594         nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
5595 
5596         /*
5597          * ZONE_MOVABLE handling.
5598          * Treat pages to be ZONE_MOVABLE in ZONE_NORMAL as absent pages
5599          * and vice versa.
5600          */
5601         if (mirrored_kernelcore && zone_movable_pfn[nid]) {
5602                 unsigned long start_pfn, end_pfn;
5603                 struct memblock_region *r;
5604 
5605                 for_each_memblock(memory, r) {
5606                         start_pfn = clamp(memblock_region_memory_base_pfn(r),
5607                                           zone_start_pfn, zone_end_pfn);
5608                         end_pfn = clamp(memblock_region_memory_end_pfn(r),
5609                                         zone_start_pfn, zone_end_pfn);
5610 
5611                         if (zone_type == ZONE_MOVABLE &&
5612                             memblock_is_mirror(r))
5613                                 nr_absent += end_pfn - start_pfn;
5614 
5615                         if (zone_type == ZONE_NORMAL &&
5616                             !memblock_is_mirror(r))
5617                                 nr_absent += end_pfn - start_pfn;
5618                 }
5619         }
5620 
5621         return nr_absent;
5622 }
5623 
5624 #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5625 static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
5626                                         unsigned long zone_type,
5627                                         unsigned long node_start_pfn,
5628                                         unsigned long node_end_pfn,
5629                                         unsigned long *zone_start_pfn,
5630                                         unsigned long *zone_end_pfn,
5631                                         unsigned long *zones_size)
5632 {
5633         unsigned int zone;
5634 
5635         *zone_start_pfn = node_start_pfn;
5636         for (zone = 0; zone < zone_type; zone++)
5637                 *zone_start_pfn += zones_size[zone];
5638 
5639         *zone_end_pfn = *zone_start_pfn + zones_size[zone_type];
5640 
5641         return zones_size[zone_type];
5642 }
5643 
5644 static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
5645                                                 unsigned long zone_type,
5646                                                 unsigned long node_start_pfn,
5647                                                 unsigned long node_end_pfn,
5648                                                 unsigned long *zholes_size)
5649 {
5650         if (!zholes_size)
5651                 return 0;
5652 
5653         return zholes_size[zone_type];
5654 }
5655 
5656 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5657 
5658 static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
5659                                                 unsigned long node_start_pfn,
5660                                                 unsigned long node_end_pfn,
5661                                                 unsigned long *zones_size,
5662                                                 unsigned long *zholes_size)
5663 {
5664         unsigned long realtotalpages = 0, totalpages = 0;
5665         enum zone_type i;
5666 
5667         for (i = 0; i < MAX_NR_ZONES; i++) {
5668                 struct zone *zone = pgdat->node_zones + i;
5669                 unsigned long zone_start_pfn, zone_end_pfn;
5670                 unsigned long size, real_size;
5671 
5672                 size = zone_spanned_pages_in_node(pgdat->node_id, i,
5673                                                   node_start_pfn,
5674                                                   node_end_pfn,
5675                                                   &zone_start_pfn,
5676                                                   &zone_end_pfn,
5677                                                   zones_size);
5678                 real_size = size - zone_absent_pages_in_node(pgdat->node_id, i,
5679                                                   node_start_pfn, node_end_pfn,
5680                                                   zholes_size);
5681                 if (size)
5682                         zone->zone_start_pfn = zone_start_pfn;
5683                 else
5684                         zone->zone_start_pfn = 0;
5685                 zone->spanned_pages = size;
5686                 zone->present_pages = real_size;
5687 
5688                 totalpages += size;
5689                 realtotalpages += real_size;
5690         }
5691 
5692         pgdat->node_spanned_pages = totalpages;
5693         pgdat->node_present_pages = realtotalpages;
5694         printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
5695                                                         realtotalpages);
5696 }
5697 
5698 #ifndef CONFIG_SPARSEMEM
5699 /*
5700  * Calculate the size of the zone->blockflags rounded to an unsigned long
5701  * Start by making sure zonesize is a multiple of pageblock_order by rounding
5702  * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
5703  * round what is now in bits to nearest long in bits, then return it in
5704  * bytes.
5705  */
5706 static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
5707 {
5708         unsigned long usemapsize;
5709 
5710         zonesize += zone_start_pfn & (pageblock_nr_pages-1);
5711         usemapsize = roundup(zonesize, pageblock_nr_pages);
5712         usemapsize = usemapsize >> pageblock_order;
5713         usemapsize *= NR_PAGEBLOCK_BITS;
5714         usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
5715 
5716         return usemapsize / 8;
5717 }
5718 
5719 static void __init setup_usemap(struct pglist_data *pgdat,
5720                                 struct zone *zone,
5721                                 unsigned long zone_start_pfn,
5722                                 unsigned long zonesize)
5723 {
5724         unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
5725         zone->pageblock_flags = NULL;
5726         if (usemapsize)
5727                 zone->pageblock_flags =
5728                         memblock_virt_alloc_node_nopanic(usemapsize,
5729                                                          pgdat->node_id);
5730 }
5731 #else
5732 static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
5733                                 unsigned long zone_start_pfn, unsigned long zonesize) {}
5734 #endif /* CONFIG_SPARSEMEM */
5735 
5736 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
5737 
5738 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
5739 void __paginginit set_pageblock_order(void)
5740 {
5741         unsigned int order;
5742 
5743         /* Check that pageblock_nr_pages has not already been setup */
5744         if (pageblock_order)
5745                 return;
5746 
5747         if (HPAGE_SHIFT > PAGE_SHIFT)
5748                 order = HUGETLB_PAGE_ORDER;
5749         else
5750                 order = MAX_ORDER - 1;
5751 
5752         /*
5753          * Assume the largest contiguous order of interest is a huge page.
5754          * This value may be variable depending on boot parameters on IA64 and
5755          * powerpc.
5756          */
5757         pageblock_order = order;
5758 }
5759 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
5760 
5761 /*
5762  * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
5763  * is unused as pageblock_order is set at compile-time. See
5764  * include/linux/pageblock-flags.h for the values of pageblock_order based on
5765  * the kernel config
5766  */
5767 void __paginginit set_pageblock_order(void)
5768 {
5769 }
5770 
5771 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
5772 
5773 static unsigned long __paginginit calc_memmap_size(unsigned long spanned_pages,
5774                                                    unsigned long present_pages)
5775 {
5776         unsigned long pages = spanned_pages;
5777 
5778         /*
5779          * Provide a more accurate estimation if there are holes within
5780          * the zone and SPARSEMEM is in use. If there are holes within the
5781          * zone, each populated memory region may cost us one or two extra
5782          * memmap pages due to alignment because memmap pages for each
5783          * populated regions may not naturally algined on page boundary.
5784          * So the (present_pages >> 4) heuristic is a tradeoff for that.
5785          */
5786         if (spanned_pages > present_pages + (present_pages >> 4) &&
5787             IS_ENABLED(CONFIG_SPARSEMEM))
5788                 pages = present_pages;
5789 
5790         return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
5791 }
5792 
5793 /*
5794  * Set up the zone data structures:
5795  *   - mark all pages reserved
5796  *   - mark all memory queues empty
5797  *   - clear the memory bitmaps
5798  *
5799  * NOTE: pgdat should get zeroed by caller.
5800  */
5801 static void __paginginit free_area_init_core(struct pglist_data *pgdat)
5802 {
5803         enum zone_type j;
5804         int nid = pgdat->node_id;
5805         int ret;
5806 
5807         pgdat_resize_init(pgdat);
5808 #ifdef CONFIG_NUMA_BALANCING
5809         spin_lock_init(&pgdat->numabalancing_migrate_lock);
5810         pgdat->numabalancing_migrate_nr_pages = 0;
5811         pgdat->numabalancing_migrate_next_window = jiffies;
5812 #endif
5813 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5814         spin_lock_init(&pgdat->split_queue_lock);
5815         INIT_LIST_HEAD(&pgdat->split_queue);
5816         pgdat->split_queue_len = 0;
5817 #endif
5818         init_waitqueue_head(&pgdat->kswapd_wait);
5819         init_waitqueue_head(&pgdat->pfmemalloc_wait);
5820 #ifdef CONFIG_COMPACTION
5821         init_waitqueue_head(&pgdat->kcompactd_wait);
5822 #endif
5823         pgdat_page_ext_init(pgdat);
5824         spin_lock_init(&pgdat->lru_lock);
5825         lruvec_init(node_lruvec(pgdat));
5826 
5827         for (j = 0; j < MAX_NR_ZONES; j++) {
5828                 struct zone *zone = pgdat->node_zones + j;
5829                 unsigned long size, realsize, freesize, memmap_pages;
5830                 unsigned long zone_start_pfn = zone->zone_start_pfn;
5831 
5832                 size = zone->spanned_pages;
5833                 realsize = freesize = zone->present_pages;
5834 
5835                 /*
5836                  * Adjust freesize so that it accounts for how much memory
5837                  * is used by this zone for memmap. This affects the watermark
5838                  * and per-cpu initialisations
5839                  */
5840                 memmap_pages = calc_memmap_size(size, realsize);
5841                 if (!is_highmem_idx(j)) {
5842                         if (freesize >= memmap_pages) {
5843                                 freesize -= memmap_pages;
5844                                 if (memmap_pages)
5845                                         printk(KERN_DEBUG
5846                                                "  %s zone: %lu pages used for memmap\n",
5847                                                zone_names[j], memmap_pages);
5848                         } else
5849                                 pr_warn("  %s zone: %lu pages exceeds freesize %lu\n",
5850                                         zone_names[j], memmap_pages, freesize);
5851                 }
5852 
5853                 /* Account for reserved pages */
5854                 if (j == 0 && freesize > dma_reserve) {
5855                         freesize -= dma_reserve;
5856                         printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
5857                                         zone_names[0], dma_reserve);
5858                 }
5859 
5860                 if (!is_highmem_idx(j))
5861                         nr_kernel_pages += freesize;
5862                 /* Charge for highmem memmap if there are enough kernel pages */
5863                 else if (nr_kernel_pages > memmap_pages * 2)
5864                         nr_kernel_pages -= memmap_pages;
5865                 nr_all_pages += freesize;
5866 
5867                 /*
5868                  * Set an approximate value for lowmem here, it will be adjusted
5869                  * when the bootmem allocator frees pages into the buddy system.
5870                  * And all highmem pages will be managed by the buddy system.
5871                  */
5872                 zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
5873 #ifdef CONFIG_NUMA
5874                 zone->node = nid;
5875 #endif
5876                 zone->name = zone_names[j];
5877                 zone->zone_pgdat = pgdat;
5878                 spin_lock_init(&zone->lock);
5879                 zone_seqlock_init(zone);
5880                 zone_pcp_init(zone);
5881 
5882                 if (!size)
5883                         continue;
5884 
5885                 set_pageblock_order();
5886                 setup_usemap(pgdat, zone, zone_start_pfn, size);
5887                 ret = init_currently_empty_zone(zone, zone_start_pfn, size);
5888                 BUG_ON(ret);
5889                 memmap_init(size, nid, j, zone_start_pfn);
5890         }
5891 }
5892 
5893 static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
5894 {
5895         unsigned long __maybe_unused start = 0;
5896         unsigned long __maybe_unused offset = 0;
5897 
5898         /* Skip empty nodes */
5899         if (!pgdat->node_spanned_pages)
5900                 return;
5901 
5902 #ifdef CONFIG_FLAT_NODE_MEM_MAP
5903         start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
5904         offset = pgdat->node_start_pfn - start;
5905         /* ia64 gets its own node_mem_map, before this, without bootmem */
5906         if (!pgdat->node_mem_map) {
5907                 unsigned long size, end;
5908                 struct page *map;
5909 
5910                 /*
5911                  * The zone's endpoints aren't required to be MAX_ORDER
5912                  * aligned but the node_mem_map endpoints must be in order
5913                  * for the buddy allocator to function correctly.
5914                  */
5915                 end = pgdat_end_pfn(pgdat);
5916                 end = ALIGN(end, MAX_ORDER_NR_PAGES);
5917                 size =  (end - start) * sizeof(struct page);
5918                 map = alloc_remap(pgdat->node_id, size);
5919                 if (!map)
5920                         map = memblock_virt_alloc_node_nopanic(size,
5921                                                                pgdat->node_id);
5922                 pgdat->node_mem_map = map + offset;
5923         }
5924 #ifndef CONFIG_NEED_MULTIPLE_NODES
5925         /*
5926          * With no DISCONTIG, the global mem_map is just set as node 0's
5927          */
5928         if (pgdat == NODE_DATA(0)) {
5929                 mem_map = NODE_DATA(0)->node_mem_map;
5930 #if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM)
5931                 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
5932                         mem_map -= offset;
5933 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5934         }
5935 #endif
5936 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
5937 }
5938 
5939 void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
5940                 unsigned long node_start_pfn, unsigned long *zholes_size)
5941 {
5942         pg_data_t *pgdat = NODE_DATA(nid);
5943         unsigned long start_pfn = 0;
5944         unsigned long end_pfn = 0;
5945 
5946         /* pg_data_t should be reset to zero when it's allocated */
5947         WARN_ON(pgdat->nr_zones || pgdat->kswapd_classzone_idx);
5948 
5949         reset_deferred_meminit(pgdat);
5950         pgdat->node_id = nid;
5951         pgdat->node_start_pfn = node_start_pfn;
5952         pgdat->per_cpu_nodestats = NULL;
5953 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5954         get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
5955         pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
5956                 (u64)start_pfn << PAGE_SHIFT,
5957                 end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
5958 #else
5959         start_pfn = node_start_pfn;
5960 #endif
5961         calculate_node_totalpages(pgdat, start_pfn, end_pfn,
5962                                   zones_size, zholes_size);
5963 
5964         alloc_node_mem_map(pgdat);
5965 #ifdef CONFIG_FLAT_NODE_MEM_MAP
5966         printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
5967                 nid, (unsigned long)pgdat,
5968                 (unsigned long)pgdat->node_mem_map);
5969 #endif
5970 
5971         free_area_init_core(pgdat);
5972 }
5973 
5974 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
5975 
5976 #if MAX_NUMNODES > 1
5977 /*
5978  * Figure out the number of possible node ids.
5979  */
5980 void __init setup_nr_node_ids(void)
5981 {
5982         unsigned int highest;
5983 
5984         highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES);
5985         nr_node_ids = highest + 1;
5986 }
5987 #endif
5988 
5989 /**
5990  * node_map_pfn_alignment - determine the maximum internode alignment
5991  *
5992  * This function should be called after node map is populated and sorted.
5993  * It calculates the maximum power of two alignment which can distinguish
5994  * all the nodes.
5995  *
5996  * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
5997  * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)).  If the
5998  * nodes are shifted by 256MiB, 256MiB.  Note that if only the last node is
5999  * shifted, 1GiB is enough and this function will indicate so.
6000  *
6001  * This is used to test whether pfn -> nid mapping of the chosen memory
6002  * model has fine enough granularity to avoid incorrect mapping for the
6003  * populated node map.
6004  *
6005  * Returns the determined alignment in pfn's.  0 if there is no alignment
6006  * requirement (single node).
6007  */
6008 unsigned long __init node_map_pfn_alignment(void)
6009 {
6010         unsigned long accl_mask = 0, last_end = 0;
6011         unsigned long start, end, mask;
6012         int last_nid = -1;
6013         int i, nid;
6014 
6015         for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
6016                 if (!start || last_nid < 0 || last_nid == nid) {
6017                         last_nid = nid;
6018                         last_end = end;
6019                         continue;
6020                 }
6021 
6022                 /*
6023                  * Start with a mask granular enough to pin-point to the
6024                  * start pfn and tick off bits one-by-one until it becomes
6025                  * too coarse to separate the current node from the last.
6026                  */
6027                 mask = ~((1 << __ffs(start)) - 1);
6028                 while (mask && last_end <= (start & (mask << 1)))
6029                         mask <<= 1;
6030 
6031                 /* accumulate all internode masks */
6032                 accl_mask |= mask;
6033         }
6034 
6035         /* convert mask to number of pages */
6036         return ~accl_mask + 1;
6037 }
6038 
6039 /* Find the lowest pfn for a node */
6040 static unsigned long __init find_min_pfn_for_node(int nid)
6041 {
6042         unsigned long min_pfn = ULONG_MAX;
6043         unsigned long start_pfn;
6044         int i;
6045 
6046         for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
6047                 min_pfn = min(min_pfn, start_pfn);
6048 
6049         if (min_pfn == ULONG_MAX) {
6050                 pr_warn("Could not find start_pfn for node %d\n", nid);
6051                 return 0;
6052         }
6053 
6054         return min_pfn;
6055 }
6056 
6057 /**
6058  * find_min_pfn_with_active_regions - Find the minimum PFN registered
6059  *
6060  * It returns the minimum PFN based on information provided via
6061  * memblock_set_node().
6062  */
6063 unsigned long __init find_min_pfn_with_active_regions(void)
6064 {
6065         return find_min_pfn_for_node(MAX_NUMNODES);
6066 }
6067 
6068 /*
6069  * early_calculate_totalpages()
6070  * Sum pages in active regions for movable zone.
6071  * Populate N_MEMORY for calculating usable_nodes.
6072  */
6073 static unsigned long __init early_calculate_totalpages(void)
6074 {
6075         unsigned long totalpages = 0;
6076         unsigned long start_pfn, end_pfn;
6077         int i, nid;
6078 
6079         for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
6080                 unsigned long pages = end_pfn - start_pfn;
6081 
6082                 totalpages += pages;
6083                 if (pages)
6084                         node_set_state(nid, N_MEMORY);
6085         }
6086         return totalpages;
6087 }
6088 
6089 /*
6090  * Find the PFN the Movable zone begins in each node. Kernel memory
6091  * is spread evenly between nodes as long as the nodes have enough
6092  * memory. When they don't, some nodes will have more kernelcore than
6093  * others
6094  */
6095 static void __init find_zone_movable_pfns_for_nodes(void)
6096 {
6097         int i, nid;
6098         unsigned long usable_startpfn;
6099         unsigned long kernelcore_node, kernelcore_remaining;
6100         /* save the state before borrow the nodemask */
6101         nodemask_t saved_node_state = node_states[N_MEMORY];
6102         unsigned long totalpages = early_calculate_totalpages();
6103         int usable_nodes = nodes_weight(node_states[N_MEMORY]);
6104         struct memblock_region *r;
6105 
6106         /* Need to find movable_zone earlier when movable_node is specified. */
6107         find_usable_zone_for_movable();
6108 
6109         /*
6110          * If movable_node is specified, ignore kernelcore and movablecore
6111          * options.
6112          */
6113         if (movable_node_is_enabled()) {
6114                 for_each_memblock(memory, r) {
6115                         if (!memblock_is_hotpluggable(r))
6116                                 continue;
6117 
6118                         nid = r->nid;
6119 
6120                         usable_startpfn = PFN_DOWN(r->base);
6121                         zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
6122                                 min(usable_startpfn, zone_movable_pfn[nid]) :
6123                                 usable_startpfn;
6124                 }
6125 
6126                 goto out2;
6127         }
6128 
6129         /*
6130          * If kernelcore=mirror is specified, ignore movablecore option
6131          */
6132         if (mirrored_kernelcore) {
6133                 bool mem_below_4gb_not_mirrored = false;
6134 
6135                 for_each_memblock(memory, r) {
6136                         if (memblock_is_mirror(r))
6137                                 continue;
6138 
6139                         nid = r->nid;
6140 
6141                         usable_startpfn = memblock_region_memory_base_pfn(r);
6142 
6143                         if (usable_startpfn < 0x100000) {
6144                                 mem_below_4gb_not_mirrored = true;
6145                                 continue;
6146                         }
6147 
6148                         zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
6149                                 min(usable_startpfn, zone_movable_pfn[nid]) :
6150                                 usable_startpfn;
6151                 }
6152 
6153                 if (mem_below_4gb_not_mirrored)
6154                         pr_warn("This configuration results in unmirrored kernel memory.");
6155 
6156                 goto out2;
6157         }
6158 
6159         /*
6160          * If movablecore=nn[KMG] was specified, calculate what size of
6161          * kernelcore that corresponds so that memory usable for
6162          * any allocation type is evenly spread. If both kernelcore
6163          * and movablecore are specified, then the value of kernelcore
6164          * will be used for required_kernelcore if it's greater than
6165          * what movablecore would have allowed.
6166          */
6167         if (required_movablecore) {
6168                 unsigned long corepages;
6169 
6170                 /*
6171                  * Round-up so that ZONE_MOVABLE is at least as large as what
6172                  * was requested by the user
6173                  */
6174                 required_movablecore =
6175                         roundup(required_movablecore, MAX_ORDER_NR_PAGES);
6176                 required_movablecore = min(totalpages, required_movablecore);
6177                 corepages = totalpages - required_movablecore;
6178 
6179                 required_kernelcore = max(required_kernelcore, corepages);
6180         }
6181 
6182         /*
6183          * If kernelcore was not specified or kernelcore size is larger
6184          * than totalpages, there is no ZONE_MOVABLE.
6185          */
6186         if (!required_kernelcore || required_kernelcore >= totalpages)
6187                 goto out;
6188 
6189         /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
6190         usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
6191 
6192 restart:
6193         /* Spread kernelcore memory as evenly as possible throughout nodes */
6194         kernelcore_node = required_kernelcore / usable_nodes;
6195         for_each_node_state(nid, N_MEMORY) {
6196                 unsigned long start_pfn, end_pfn;
6197 
6198                 /*
6199                  * Recalculate kernelcore_node if the division per node
6200                  * now exceeds what is necessary to satisfy the requested
6201                  * amount of memory for the kernel
6202                  */
6203                 if (required_kernelcore < kernelcore_node)
6204                         kernelcore_node = required_kernelcore / usable_nodes;
6205 
6206                 /*
6207                  * As the map is walked, we track how much memory is usable
6208                  * by the kernel using kernelcore_remaining. When it is
6209                  * 0, the rest of the node is usable by ZONE_MOVABLE
6210                  */
6211                 kernelcore_remaining = kernelcore_node;
6212 
6213                 /* Go through each range of PFNs within this node */
6214                 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
6215                         unsigned long size_pages;
6216 
6217                         start_pfn = max(start_pfn, zone_movable_pfn[nid]);
6218                         if (start_pfn >= end_pfn)
6219                                 continue;
6220 
6221                         /* Account for what is only usable for kernelcore */
6222                         if (start_pfn < usable_startpfn) {
6223                                 unsigned long kernel_pages;
6224                                 kernel_pages = min(end_pfn, usable_startpfn)
6225                                                                 - start_pfn;
6226 
6227                                 kernelcore_remaining -= min(kernel_pages,
6228                                                         kernelcore_remaining);
6229                                 required_kernelcore -= min(kernel_pages,
6230                                                         required_kernelcore);
6231 
6232                                 /* Continue if range is now fully accounted */
6233                                 if (end_pfn <= usable_startpfn) {
6234 
6235                                         /*
6236                                          * Push zone_movable_pfn to the end so
6237                                          * that if we have to rebalance
6238                                          * kernelcore across nodes, we will
6239                                          * not double account here
6240                                          */
6241                                         zone_movable_pfn[nid] = end_pfn;
6242                                         continue;
6243                                 }
6244                                 start_pfn = usable_startpfn;
6245                         }
6246 
6247                         /*
6248                          * The usable PFN range for ZONE_MOVABLE is from
6249                          * start_pfn->end_pfn. Calculate size_pages as the
6250                          * number of pages used as kernelcore
6251                          */
6252                         size_pages = end_pfn - start_pfn;
6253                         if (size_pages > kernelcore_remaining)
6254                                 size_pages = kernelcore_remaining;
6255                         zone_movable_pfn[nid] = start_pfn + size_pages;
6256 
6257                         /*
6258                          * Some kernelcore has been met, update counts and
6259                          * break if the kernelcore for this node has been
6260                          * satisfied
6261                          */
6262                         required_kernelcore -= min(required_kernelcore,
6263                                                                 size_pages);
6264                         kernelcore_remaining -= size_pages;
6265                         if (!kernelcore_remaining)
6266                                 break;
6267                 }
6268         }
6269 
6270         /*
6271          * If there is still required_kernelcore, we do another pass with one
6272          * less node in the count. This will push zone_movable_pfn[nid] further
6273          * along on the nodes that still have memory until kernelcore is
6274          * satisfied
6275          */
6276         usable_nodes--;
6277         if (usable_nodes && required_kernelcore > usable_nodes)
6278                 goto restart;
6279 
6280 out2:
6281         /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
6282         for (nid = 0; nid < MAX_NUMNODES; nid++)
6283                 zone_movable_pfn[nid] =
6284                         roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
6285 
6286 out:
6287         /* restore the node_state */
6288         node_states[N_MEMORY] = saved_node_state;
6289 }
6290 
6291 /* Any regular or high memory on that node ? */
6292 static void check_for_memory(pg_data_t *pgdat, int nid)
6293 {
6294         enum zone_type zone_type;
6295 
6296         if (N_MEMORY == N_NORMAL_MEMORY)
6297                 return;
6298 
6299         for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
6300                 struct zone *zone = &pgdat->node_zones[zone_type];
6301                 if (populated_zone(zone)) {
6302                         node_set_state(nid, N_HIGH_MEMORY);
6303                         if (N_NORMAL_MEMORY != N_HIGH_MEMORY &&
6304                             zone_type <= ZONE_NORMAL)
6305                                 node_set_state(nid, N_NORMAL_MEMORY);
6306                         break;
6307                 }
6308         }
6309 }
6310 
6311 /**
6312  * free_area_init_nodes - Initialise all pg_data_t and zone data
6313  * @max_zone_pfn: an array of max PFNs for each zone
6314  *
6315  * This will call free_area_init_node() for each active node in the system.
6316  * Using the page ranges provided by memblock_set_node(), the size of each
6317  * zone in each node and their holes is calculated. If the maximum PFN
6318  * between two adjacent zones match, it is assumed that the zone is empty.
6319  * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
6320  * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
6321  * starts where the previous one ended. For example, ZONE_DMA32 starts
6322  * at arch_max_dma_pfn.
6323  */
6324 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
6325 {
6326         unsigned long start_pfn, end_pfn;
6327         int i, nid;
6328 
6329         /* Record where the zone boundaries are */
6330         memset(arch_zone_lowest_possible_pfn, 0,
6331                                 sizeof(arch_zone_lowest_possible_pfn));
6332         memset(arch_zone_highest_possible_pfn, 0,
6333                                 sizeof(arch_zone_highest_possible_pfn));
6334 
6335         start_pfn = find_min_pfn_with_active_regions();
6336 
6337         for (i = 0; i < MAX_NR_ZONES; i++) {
6338                 if (i == ZONE_MOVABLE)
6339                         continue;
6340 
6341                 end_pfn = max(max_zone_pfn[i], start_pfn);
6342                 arch_zone_lowest_possible_pfn[i] = start_pfn;
6343                 arch_zone_highest_possible_pfn[i] = end_pfn;
6344 
6345                 start_pfn = end_pfn;
6346         }
6347         arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
6348         arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
6349 
6350         /* Find the PFNs that ZONE_MOVABLE begins at in each node */
6351         memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
6352         find_zone_movable_pfns_for_nodes();
6353 
6354         /* Print out the zone ranges */
6355         pr_info("Zone ranges:\n");
6356         for (i = 0; i < MAX_NR_ZONES; i++) {
6357                 if (i == ZONE_MOVABLE)
6358                         continue;
6359                 pr_info("  %-8s ", zone_names[i]);
6360                 if (arch_zone_lowest_possible_pfn[i] ==
6361                                 arch_zone_highest_possible_pfn[i])
6362                         pr_cont("empty\n");
6363                 else
6364                         pr_cont("[mem %#018Lx-%#018Lx]\n",
6365                                 (u64)arch_zone_lowest_possible_pfn[i]
6366                                         << PAGE_SHIFT,
6367                                 ((u64)arch_zone_highest_possible_pfn[i]
6368                                         << PAGE_SHIFT) - 1);
6369         }
6370 
6371         /* Print out the PFNs ZONE_MOVABLE begins at in each node */
6372         pr_info("Movable zone start for each node\n");
6373         for (i = 0; i < MAX_NUMNODES; i++) {
6374                 if (zone_movable_pfn[i])
6375                         pr_info("  Node %d: %#018Lx\n", i,
6376                                (u64)zone_movable_pfn[i] << PAGE_SHIFT);
6377         }
6378 
6379         /* Print out the early node map */
6380         pr_info("Early memory node ranges\n");
6381         for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
6382                 pr_info("  node %3d: [mem %#018Lx-%#018Lx]\n", nid,
6383                         (u64)start_pfn << PAGE_SHIFT,
6384                         ((u64)end_pfn << PAGE_SHIFT) - 1);
6385 
6386         /* Initialise every node */
6387         mminit_verify_pageflags_layout();
6388         setup_nr_node_ids();
6389         for_each_online_node(nid) {
6390                 pg_data_t *pgdat = NODE_DATA(nid);
6391                 free_area_init_node(nid, NULL,
6392                                 find_min_pfn_for_node(nid), NULL);
6393 
6394                 /* Any memory on that node */
6395                 if (pgdat->node_present_pages)
6396                         node_set_state(nid, N_MEMORY);
6397                 check_for_memory(pgdat, nid);
6398         }
6399 }
6400 
6401 static int __init cmdline_parse_core(char *p, unsigned long *core)
6402 {
6403         unsigned long long coremem;
6404         if (!p)
6405                 return -EINVAL;
6406 
6407         coremem = memparse(p, &p);
6408         *core = coremem >> PAGE_SHIFT;
6409 
6410         /* Paranoid check that UL is enough for the coremem value */
6411         WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
6412 
6413         return 0;
6414 }
6415 
6416 /*
6417  * kernelcore=size sets the amount of memory for use for allocations that
6418  * cannot be reclaimed or migrated.
6419  */
6420 static int __init cmdline_parse_kernelcore(char *p)
6421 {
6422         /* parse kernelcore=mirror */
6423         if (parse_option_str(p, "mirror")) {
6424                 mirrored_kernelcore = true;
6425                 return 0;
6426         }
6427 
6428         return cmdline_parse_core(p, &required_kernelcore);
6429 }
6430 
6431 /*
6432  * movablecore=size sets the amount of memory for use for allocations that
6433  * can be reclaimed or migrated.
6434  */
6435 static int __init cmdline_parse_movablecore(char *p)
6436 {
6437         return cmdline_parse_core(p, &required_movablecore);
6438 }
6439 
6440 early_param("kernelcore", cmdline_parse_kernelcore);
6441 early_param("movablecore", cmdline_parse_movablecore);
6442 
6443 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
6444 
6445 void adjust_managed_page_count(struct page *page, long count)
6446 {
6447         spin_lock(&managed_page_count_lock);
6448         page_zone(page)->managed_pages += count;
6449         totalram_pages += count;
6450 #ifdef CONFIG_HIGHMEM
6451         if (PageHighMem(page))
6452                 totalhigh_pages += count;
6453 #endif
6454         spin_unlock(&managed_page_count_lock);
6455 }
6456 EXPORT_SYMBOL(adjust_managed_page_count);
6457 
6458 unsigned long free_reserved_area(void *start, void *end, int poison, char *s)
6459 {
6460         void *pos;
6461         unsigned long pages = 0;
6462 
6463         start = (void *)PAGE_ALIGN((unsigned long)start);
6464         end = (void *)((unsigned long)end & PAGE_MASK);
6465         for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
6466                 if ((unsigned int)poison <= 0xFF)
6467                         memset(pos, poison, PAGE_SIZE);
6468                 free_reserved_page(virt_to_page(pos));
6469         }
6470 
6471         if (pages && s)
6472                 pr_info("Freeing %s memory: %ldK\n",
6473                         s, pages << (PAGE_SHIFT - 10));
6474 
6475         return pages;
6476 }
6477 EXPORT_SYMBOL(free_reserved_area);
6478 
6479 #ifdef  CONFIG_HIGHMEM
6480 void free_highmem_page(struct page *page)
6481 {
6482         __free_reserved_page(page);
6483         totalram_pages++;
6484         page_zone(page)->managed_pages++;
6485         totalhigh_pages++;
6486 }
6487 #endif
6488 
6489 
6490 void __init mem_init_print_info(const char *str)
6491 {
6492         unsigned long physpages, codesize, datasize, rosize, bss_size;
6493         unsigned long init_code_size, init_data_size;
6494 
6495         physpages = get_num_physpages();
6496         codesize = _etext - _stext;
6497         datasize = _edata - _sdata;
6498         rosize = __end_rodata - __start_rodata;
6499         bss_size = __bss_stop - __bss_start;
6500         init_data_size = __init_end - __init_begin;
6501         init_code_size = _einittext - _sinittext;
6502 
6503         /*
6504          * Detect special cases and adjust section sizes accordingly:
6505          * 1) .init.* may be embedded into .data sections
6506          * 2) .init.text.* may be out of [__init_begin, __init_end],
6507          *    please refer to arch/tile/kernel/vmlinux.lds.S.
6508          * 3) .rodata.* may be embedded into .text or .data sections.
6509          */
6510 #define adj_init_size(start, end, size, pos, adj) \
6511         do { \
6512                 if (start <= pos && pos < end && size > adj) \
6513                         size -= adj; \
6514         } while (0)
6515 
6516         adj_init_size(__init_begin, __init_end, init_data_size,
6517                      _sinittext, init_code_size);
6518         adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
6519         adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
6520         adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
6521         adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
6522 
6523 #undef  adj_init_size
6524 
6525         pr_info("Memory: %luK/%luK available (%luK kernel code, %luK rwdata, %luK rodata, %luK init, %luK bss, %luK reserved, %luK cma-reserved"
6526 #ifdef  CONFIG_HIGHMEM
6527                 ", %luK highmem"
6528 #endif
6529                 "%s%s)\n",
6530                 nr_free_pages() << (PAGE_SHIFT - 10),
6531                 physpages << (PAGE_SHIFT - 10),
6532                 codesize >> 10, datasize >> 10, rosize >> 10,
6533                 (init_data_size + init_code_size) >> 10, bss_size >> 10,
6534                 (physpages - totalram_pages - totalcma_pages) << (PAGE_SHIFT - 10),
6535                 totalcma_pages << (PAGE_SHIFT - 10),
6536 #ifdef  CONFIG_HIGHMEM
6537                 totalhigh_pages << (PAGE_SHIFT - 10),
6538 #endif
6539                 str ? ", " : "", str ? str : "");
6540 }
6541 
6542 /**
6543  * set_dma_reserve - set the specified number of pages reserved in the first zone
6544  * @new_dma_reserve: The number of pages to mark reserved
6545  *
6546  * The per-cpu batchsize and zone watermarks are determined by managed_pages.
6547  * In the DMA zone, a significant percentage may be consumed by kernel image
6548  * and other unfreeable allocations which can skew the watermarks badly. This
6549  * function may optionally be used to account for unfreeable pages in the
6550  * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
6551  * smaller per-cpu batchsize.
6552  */
6553 void __init set_dma_reserve(unsigned long new_dma_reserve)
6554 {
6555         dma_reserve = new_dma_reserve;
6556 }
6557 
6558 void __init free_area_init(unsigned long *zones_size)
6559 {
6560         free_area_init_node(0, zones_size,
6561                         __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
6562 }
6563 
6564 static int page_alloc_cpu_dead(unsigned int cpu)
6565 {
6566 
6567         lru_add_drain_cpu(cpu);
6568         drain_pages(cpu);
6569 
6570         /*
6571          * Spill the event counters of the dead processor
6572          * into the current processors event counters.
6573          * This artificially elevates the count of the current
6574          * processor.
6575          */
6576         vm_events_fold_cpu(cpu);
6577 
6578         /*
6579          * Zero the differential counters of the dead processor
6580          * so that the vm statistics are consistent.
6581          *
6582          * This is only okay since the processor is dead and cannot
6583          * race with what we are doing.
6584          */
6585         cpu_vm_stats_fold(cpu);
6586         return 0;
6587 }
6588 
6589 void __init page_alloc_init(void)
6590 {
6591         int ret;
6592 
6593         ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC_DEAD,
6594                                         "mm/page_alloc:dead", NULL,
6595                                         page_alloc_cpu_dead);
6596         WARN_ON(ret < 0);
6597 }
6598 
6599 /*
6600  * calculate_totalreserve_pages - called when sysctl_lowmem_reserve_ratio
6601  *      or min_free_kbytes changes.
6602  */
6603 static void calculate_totalreserve_pages(void)
6604 {
6605         struct pglist_data *pgdat;
6606         unsigned long reserve_pages = 0;
6607         enum zone_type i, j;
6608 
6609         for_each_online_pgdat(pgdat) {
6610 
6611                 pgdat->totalreserve_pages = 0;
6612 
6613                 for (i = 0; i < MAX_NR_ZONES; i++) {
6614                         struct zone *zone = pgdat->node_zones + i;
6615                         long max = 0;
6616 
6617                         /* Find valid and maximum lowmem_reserve in the zone */
6618                         for (j = i; j < MAX_NR_ZONES; j++) {
6619                                 if (zone->lowmem_reserve[j] > max)
6620                                         max = zone->lowmem_reserve[j];
6621                         }
6622 
6623                         /* we treat the high watermark as reserved pages. */
6624                         max += high_wmark_pages(zone);
6625 
6626                         if (max > zone->managed_pages)
6627                                 max = zone->managed_pages;
6628 
6629                         pgdat->totalreserve_pages += max;
6630 
6631                         reserve_pages += max;
6632                 }
6633         }
6634         totalreserve_pages = reserve_pages;
6635 }
6636 
6637 /*
6638  * setup_per_zone_lowmem_reserve - called whenever
6639  *      sysctl_lowmem_reserve_ratio changes.  Ensures that each zone
6640  *      has a correct pages reserved value, so an adequate number of
6641  *      pages are left in the zone after a successful __alloc_pages().
6642  */
6643 static void setup_per_zone_lowmem_reserve(void)
6644 {
6645         struct pglist_data *pgdat;
6646         enum zone_type j, idx;
6647 
6648         for_each_online_pgdat(pgdat) {
6649                 for (j = 0; j < MAX_NR_ZONES; j++) {
6650                         struct zone *zone = pgdat->node_zones + j;
6651                         unsigned long managed_pages = zone->managed_pages;
6652 
6653                         zone->lowmem_reserve[j] = 0;
6654 
6655                         idx = j;
6656                         while (idx) {
6657                                 struct zone *lower_zone;
6658 
6659                                 idx--;
6660 
6661                                 if (sysctl_lowmem_reserve_ratio[idx] < 1)
6662                                         sysctl_lowmem_reserve_ratio[idx] = 1;
6663 
6664                                 lower_zone = pgdat->node_zones + idx;
6665                                 lower_zone->lowmem_reserve[j] = managed_pages /
6666                                         sysctl_lowmem_reserve_ratio[idx];
6667                                 managed_pages += lower_zone->managed_pages;
6668                         }
6669                 }
6670         }
6671 
6672         /* update totalreserve_pages */
6673         calculate_totalreserve_pages();
6674 }
6675 
6676 static void __setup_per_zone_wmarks(void)
6677 {
6678         unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
6679         unsigned long lowmem_pages = 0;
6680         struct zone *zone;
6681         unsigned long flags;
6682 
6683         /* Calculate total number of !ZONE_HIGHMEM pages */
6684         for_each_zone(zone) {
6685                 if (!is_highmem(zone))
6686                         lowmem_pages += zone->managed_pages;
6687         }
6688 
6689         for_each_zone(zone) {
6690                 u64 tmp;
6691 
6692                 spin_lock_irqsave(&zone->lock, flags);
6693                 tmp = (u64)pages_min * zone->managed_pages;
6694                 do_div(tmp, lowmem_pages);
6695                 if (is_highmem(zone)) {
6696                         /*
6697                          * __GFP_HIGH and PF_MEMALLOC allocations usually don't
6698                          * need highmem pages, so cap pages_min to a small
6699                          * value here.
6700                          *
6701                          * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
6702                          * deltas control asynch page reclaim, and so should
6703                          * not be capped for highmem.
6704                          */
6705                         unsigned long min_pages;
6706 
6707                         min_pages = zone->managed_pages / 1024;
6708                         min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
6709                         zone->watermark[WMARK_MIN] = min_pages;
6710                 } else {
6711                         /*
6712                          * If it's a lowmem zone, reserve a number of pages
6713                          * proportionate to the zone's size.
6714                          */
6715                         zone->watermark[WMARK_MIN] = tmp;
6716                 }
6717 
6718                 /*
6719                  * Set the kswapd watermarks distance according to the
6720                  * scale factor in proportion to available memory, but
6721                  * ensure a minimum size on small systems.
6722                  */
6723                 tmp = max_t(u64, tmp >> 2,
6724                             mult_frac(zone->managed_pages,
6725                                       watermark_scale_factor, 10000));
6726 
6727                 zone->watermark[WMARK_LOW]  = min_wmark_pages(zone) + tmp;
6728                 zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2;
6729 
6730                 spin_unlock_irqrestore(&zone->lock, flags);
6731         }
6732 
6733         /* update totalreserve_pages */
6734         calculate_totalreserve_pages();
6735 }
6736 
6737 /**
6738  * setup_per_zone_wmarks - called when min_free_kbytes changes
6739  * or when memory is hot-{added|removed}
6740  *
6741  * Ensures that the watermark[min,low,high] values for each zone are set
6742  * correctly with respect to min_free_kbytes.
6743  */
6744 void setup_per_zone_wmarks(void)
6745 {
6746         mutex_lock(&zonelists_mutex);
6747         __setup_per_zone_wmarks();
6748         mutex_unlock(&zonelists_mutex);
6749 }
6750 
6751 /*
6752  * Initialise min_free_kbytes.
6753  *
6754  * For small machines we want it small (128k min).  For large machines
6755  * we want it large (64MB max).  But it is not linear, because network
6756  * bandwidth does not increase linearly with machine size.  We use
6757  *
6758  *      min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
6759  *      min_free_kbytes = sqrt(lowmem_kbytes * 16)
6760  *
6761  * which yields
6762  *
6763  * 16MB:        512k
6764  * 32MB:        724k
6765  * 64MB:        1024k
6766  * 128MB:       1448k
6767  * 256MB:       2048k
6768  * 512MB:       2896k
6769  * 1024MB:      4096k
6770  * 2048MB:      5792k
6771  * 4096MB:      8192k
6772  * 8192MB:      11584k
6773  * 16384MB:     16384k
6774  */
6775 int __meminit init_per_zone_wmark_min(void)
6776 {
6777         unsigned long lowmem_kbytes;
6778         int new_min_free_kbytes;
6779 
6780         lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
6781         new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
6782 
6783         if (new_min_free_kbytes > user_min_free_kbytes) {
6784                 min_free_kbytes = new_min_free_kbytes;
6785                 if (min_free_kbytes < 128)
6786                         min_free_kbytes = 128;
6787                 if (min_free_kbytes > 65536)
6788                         min_free_kbytes = 65536;
6789         } else {
6790                 pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
6791                                 new_min_free_kbytes, user_min_free_kbytes);
6792         }
6793         setup_per_zone_wmarks();
6794         refresh_zone_stat_thresholds();
6795         setup_per_zone_lowmem_reserve();
6796 
6797 #ifdef CONFIG_NUMA
6798         setup_min_unmapped_ratio();
6799         setup_min_slab_ratio();
6800 #endif
6801 
6802         return 0;
6803 }
6804 core_initcall(init_per_zone_wmark_min)
6805 
6806 /*
6807  * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
6808  *      that we can call two helper functions whenever min_free_kbytes
6809  *      changes.
6810  */
6811 int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write,
6812         void __user *buffer, size_t *length, loff_t *ppos)
6813 {
6814         int rc;
6815 
6816         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6817         if (rc)
6818                 return rc;
6819 
6820         if (write) {
6821                 user_min_free_kbytes = min_free_kbytes;
6822                 setup_per_zone_wmarks();
6823         }
6824         return 0;
6825 }
6826 
6827 int watermark_scale_factor_sysctl_handler(struct ctl_table *table, int write,
6828         void __user *buffer, size_t *length, loff_t *ppos)
6829 {
6830         int rc;
6831 
6832         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6833         if (rc)
6834                 return rc;
6835 
6836         if (write)
6837                 setup_per_zone_wmarks();
6838 
6839         return 0;
6840 }
6841 
6842 #ifdef CONFIG_NUMA
6843 static void setup_min_unmapped_ratio(void)
6844 {
6845         pg_data_t *pgdat;
6846         struct zone *zone;
6847 
6848         for_each_online_pgdat(pgdat)
6849                 pgdat->min_unmapped_pages = 0;
6850 
6851         for_each_zone(zone)
6852                 zone->zone_pgdat->min_unmapped_pages += (zone->managed_pages *
6853                                 sysctl_min_unmapped_ratio) / 100;
6854 }
6855 
6856 
6857 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
6858         void __user *buffer, size_t *length, loff_t *ppos)
6859 {
6860         int rc;
6861 
6862         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6863         if (rc)
6864                 return rc;
6865 
6866         setup_min_unmapped_ratio();
6867 
6868         return 0;
6869 }
6870 
6871 static void setup_min_slab_ratio(void)
6872 {
6873         pg_data_t *pgdat;
6874         struct zone *zone;
6875 
6876         for_each_online_pgdat(pgdat)
6877                 pgdat->min_slab_pages = 0;
6878 
6879         for_each_zone(zone)
6880                 zone->zone_pgdat->min_slab_pages += (zone->managed_pages *
6881                                 sysctl_min_slab_ratio) / 100;
6882 }
6883 
6884 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
6885         void __user *buffer, size_t *length, loff_t *ppos)
6886 {
6887         int rc;
6888 
6889         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
6890         if (rc)
6891                 return rc;
6892 
6893         setup_min_slab_ratio();
6894 
6895         return 0;
6896 }
6897 #endif
6898 
6899 /*
6900  * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
6901  *      proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
6902  *      whenever sysctl_lowmem_reserve_ratio changes.
6903  *
6904  * The reserve ratio obviously has absolutely no relation with the
6905  * minimum watermarks. The lowmem reserve ratio can only make sense
6906  * if in function of the boot time zone sizes.
6907  */
6908 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
6909         void __user *buffer, size_t *length, loff_t *ppos)
6910 {
6911         proc_dointvec_minmax(table, write, buffer, length, ppos);
6912         setup_per_zone_lowmem_reserve();
6913         return 0;
6914 }
6915 
6916 /*
6917  * percpu_pagelist_fraction - changes the pcp->high for each zone on each
6918  * cpu.  It is the fraction of total pages in each zone that a hot per cpu
6919  * pagelist can have before it gets flushed back to buddy allocator.
6920  */
6921 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *table, int write,
6922         void __user *buffer, size_t *length, loff_t *ppos)
6923 {
6924         struct zone *zone;
6925         int old_percpu_pagelist_fraction;
6926         int ret;
6927 
6928         mutex_lock(&pcp_batch_high_lock);
6929         old_percpu_pagelist_fraction = percpu_pagelist_fraction;
6930 
6931         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
6932         if (!write || ret < 0)
6933                 goto out;
6934 
6935         /* Sanity checking to avoid pcp imbalance */
6936         if (percpu_pagelist_fraction &&
6937             percpu_pagelist_fraction < MIN_PERCPU_PAGELIST_FRACTION) {
6938                 percpu_pagelist_fraction = old_percpu_pagelist_fraction;
6939                 ret = -EINVAL;
6940                 goto out;
6941         }
6942 
6943         /* No change? */
6944         if (percpu_pagelist_fraction == old_percpu_pagelist_fraction)
6945                 goto out;
6946 
6947         for_each_populated_zone(zone) {
6948                 unsigned int cpu;
6949 
6950                 for_each_possible_cpu(cpu)
6951                         pageset_set_high_and_batch(zone,
6952                                         per_cpu_ptr(zone->pageset, cpu));
6953         }
6954 out:
6955         mutex_unlock(&pcp_batch_high_lock);
6956         return ret;
6957 }
6958 
6959 #ifdef CONFIG_NUMA
6960 int hashdist = HASHDIST_DEFAULT;
6961 
6962 static int __init set_hashdist(char *str)
6963 {
6964         if (!str)
6965                 return 0;
6966         hashdist = simple_strtoul(str, &str, 0);
6967         return 1;
6968 }
6969 __setup("hashdist=", set_hashdist);
6970 #endif
6971 
6972 #ifndef __HAVE_ARCH_RESERVED_KERNEL_PAGES
6973 /*
6974  * Returns the number of pages that arch has reserved but
6975  * is not known to alloc_large_system_hash().
6976  */
6977 static unsigned long __init arch_reserved_kernel_pages(void)
6978 {
6979         return 0;
6980 }
6981 #endif
6982 
6983 /*
6984  * allocate a large system hash table from bootmem
6985  * - it is assumed that the hash table must contain an exact power-of-2
6986  *   quantity of entries
6987  * - limit is the number of hash buckets, not the total allocation size
6988  */
6989 void *__init alloc_large_system_hash(const char *tablename,
6990                                      unsigned long bucketsize,
6991                                      unsigned long numentries,
6992                                      int scale,
6993                                      int flags,
6994                                      unsigned int *_hash_shift,
6995                                      unsigned int *_hash_mask,
6996                                      unsigned long low_limit,
6997                                      unsigned long high_limit)
6998 {
6999         unsigned long long max = high_limit;
7000         unsigned long log2qty, size;
7001         void *table = NULL;
7002 
7003         /* allow the kernel cmdline to have a say */
7004         if (!numentries) {
7005                 /* round applicable memory size up to nearest megabyte */
7006                 numentries = nr_kernel_pages;
7007                 numentries -= arch_reserved_kernel_pages();
7008 
7009                 /* It isn't necessary when PAGE_SIZE >= 1MB */
7010                 if (PAGE_SHIFT < 20)
7011                         numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
7012 
7013                 /* limit to 1 bucket per 2^scale bytes of low memory */
7014                 if (scale > PAGE_SHIFT)
7015                         numentries >>= (scale - PAGE_SHIFT);
7016                 else
7017                         numentries <<= (PAGE_SHIFT - scale);
7018 
7019                 /* Make sure we've got at least a 0-order allocation.. */
7020                 if (unlikely(flags & HASH_SMALL)) {
7021                         /* Makes no sense without HASH_EARLY */
7022                         WARN_ON(!(flags & HASH_EARLY));
7023                         if (!(numentries >> *_hash_shift)) {
7024                                 numentries = 1UL << *_hash_shift;
7025                                 BUG_ON(!numentries);
7026                         }
7027                 } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
7028                         numentries = PAGE_SIZE / bucketsize;
7029         }
7030         numentries = roundup_pow_of_two(numentries);
7031 
7032         /* limit allocation size to 1/16 total memory by default */
7033         if (max == 0) {
7034                 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
7035                 do_div(max, bucketsize);
7036         }
7037         max = min(max, 0x80000000ULL);
7038 
7039         if (numentries < low_limit)
7040                 numentries = low_limit;
7041         if (numentries > max)
7042                 numentries = max;
7043 
7044         log2qty = ilog2(numentries);
7045 
7046         do {
7047                 size = bucketsize << log2qty;
7048                 if (flags & HASH_EARLY)
7049                         table = memblock_virt_alloc_nopanic(size, 0);
7050                 else if (hashdist)
7051                         table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
7052                 else {
7053                         /*
7054                          * If bucketsize is not a power-of-two, we may free
7055                          * some pages at the end of hash table which
7056                          * alloc_pages_exact() automatically does
7057                          */
7058                         if (get_order(size) < MAX_ORDER) {
7059                                 table = alloc_pages_exact(size, GFP_ATOMIC);
7060                                 kmemleak_alloc(table, size, 1, GFP_ATOMIC);
7061                         }
7062                 }
7063         } while (!table && size > PAGE_SIZE && --log2qty);
7064 
7065         if (!table)
7066                 panic("Failed to allocate %s hash table\n", tablename);
7067 
7068         pr_info("%s hash table entries: %ld (order: %d, %lu bytes)\n",
7069                 tablename, 1UL << log2qty, ilog2(size) - PAGE_SHIFT, size);
7070 
7071         if (_hash_shift)
7072                 *_hash_shift = log2qty;
7073         if (_hash_mask)
7074                 *_hash_mask = (1 << log2qty) - 1;
7075 
7076         return table;
7077 }
7078 
7079 /*
7080  * This function checks whether pageblock includes unmovable pages or not.
7081  * If @count is not zero, it is okay to include less @count unmovable pages
7082  *
7083  * PageLRU check without isolation or lru_lock could race so that
7084  * MIGRATE_MOVABLE block might include unmovable pages. It means you can't
7085  * expect this function should be exact.
7086  */
7087 bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
7088                          bool skip_hwpoisoned_pages)
7089 {
7090         unsigned long pfn, iter, found;
7091         int mt;
7092 
7093         /*
7094          * For avoiding noise data, lru_add_drain_all() should be called
7095          * If ZONE_MOVABLE, the zone never contains unmovable pages
7096          */
7097         if (zone_idx(zone) == ZONE_MOVABLE)
7098                 return false;
7099         mt = get_pageblock_migratetype(page);
7100         if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
7101                 return false;
7102 
7103         pfn = page_to_pfn(page);
7104         for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
7105                 unsigned long check = pfn + iter;
7106 
7107                 if (!pfn_valid_within(check))
7108                         continue;
7109 
7110                 page = pfn_to_page(check);
7111 
7112                 /*
7113                  * Hugepages are not in LRU lists, but they're movable.
7114                  * We need not scan over tail pages bacause we don't
7115                  * handle each tail page individually in migration.
7116                  */
7117                 if (PageHuge(page)) {
7118                         iter = round_up(iter + 1, 1<<compound_order(page)) - 1;
7119                         continue;
7120                 }
7121 
7122                 /*
7123                  * We can't use page_count without pin a page
7124                  * because another CPU can free compound page.
7125                  * This check already skips compound tails of THP
7126                  * because their page->_refcount is zero at all time.
7127                  */
7128                 if (!page_ref_count(page)) {
7129                         if (PageBuddy(page))
7130                                 iter += (1 << page_order(page)) - 1;
7131                         continue;
7132                 }
7133 
7134                 /*
7135                  * The HWPoisoned page may be not in buddy system, and
7136                  * page_count() is not 0.
7137                  */
7138                 if (skip_hwpoisoned_pages && PageHWPoison(page))
7139                         continue;
7140 
7141                 if (!PageLRU(page))
7142                         found++;
7143                 /*
7144                  * If there are RECLAIMABLE pages, we need to check
7145                  * it.  But now, memory offline itself doesn't call
7146                  * shrink_node_slabs() and it still to be fixed.
7147                  */
7148                 /*
7149                  * If the page is not RAM, page_count()should be 0.
7150                  * we don't need more check. This is an _used_ not-movable page.
7151                  *
7152                  * The problematic thing here is PG_reserved pages. PG_reserved
7153                  * is set to both of a memory hole page and a _used_ kernel
7154                  * page at boot.
7155                  */
7156                 if (found > count)
7157                         return true;
7158         }
7159         return false;
7160 }
7161 
7162 bool is_pageblock_removable_nolock(struct page *page)
7163 {
7164         struct zone *zone;
7165         unsigned long pfn;
7166 
7167         /*
7168          * We have to be careful here because we are iterating over memory
7169          * sections which are not zone aware so we might end up outside of
7170          * the zone but still within the section.
7171          * We have to take care about the node as well. If the node is offline
7172          * its NODE_DATA will be NULL - see page_zone.
7173          */
7174         if (!node_online(page_to_nid(page)))
7175                 return false;
7176 
7177         zone = page_zone(page);
7178         pfn = page_to_pfn(page);
7179         if (!zone_spans_pfn(zone, pfn))
7180                 return false;
7181 
7182         return !has_unmovable_pages(zone, page, 0, true);
7183 }
7184 
7185 #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA)
7186 
7187 static unsigned long pfn_max_align_down(unsigned long pfn)
7188 {
7189         return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
7190                              pageblock_nr_pages) - 1);
7191 }
7192 
7193 static unsigned long pfn_max_align_up(unsigned long pfn)
7194 {
7195         return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
7196                                 pageblock_nr_pages));
7197 }
7198 
7199 /* [start, end) must belong to a single zone. */
7200 static int __alloc_contig_migrate_range(struct compact_control *cc,
7201                                         unsigned long start, unsigned long end)
7202 {
7203         /* This function is based on compact_zone() from compaction.c. */
7204         unsigned long nr_reclaimed;
7205         unsigned long pfn = start;
7206         unsigned int tries = 0;
7207         int ret = 0;
7208 
7209         migrate_prep();
7210 
7211         while (pfn < end || !list_empty(&cc->migratepages)) {
7212                 if (fatal_signal_pending(current)) {
7213                         ret = -EINTR;
7214                         break;
7215                 }
7216 
7217                 if (list_empty(&cc->migratepages)) {
7218                         cc->nr_migratepages = 0;
7219                         pfn = isolate_migratepages_range(cc, pfn, end);
7220                         if (!pfn) {
7221                                 ret = -EINTR;
7222                                 break;
7223                         }
7224                         tries = 0;
7225                 } else if (++tries == 5) {
7226                         ret = ret < 0 ? ret : -EBUSY;
7227                         break;
7228                 }
7229 
7230                 nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
7231                                                         &cc->migratepages);
7232                 cc->nr_migratepages -= nr_reclaimed;
7233 
7234                 ret = migrate_pages(&cc->migratepages, alloc_migrate_target,
7235                                     NULL, 0, cc->mode, MR_CMA);
7236         }
7237         if (ret < 0) {
7238                 putback_movable_pages(&cc->migratepages);
7239                 return ret;
7240         }
7241         return 0;
7242 }
7243 
7244 /**
7245  * alloc_contig_range() -- tries to allocate given range of pages
7246  * @start:      start PFN to allocate
7247  * @end:        one-past-the-last PFN to allocate
7248  * @migratetype:        migratetype of the underlaying pageblocks (either
7249  *                      #MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
7250  *                      in range must have the same migratetype and it must
7251  *                      be either of the two.
7252  *
7253  * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
7254  * aligned, however it's the caller's responsibility to guarantee that
7255  * we are the only thread that changes migrate type of pageblocks the
7256  * pages fall in.
7257  *
7258  * The PFN range must belong to a single zone.
7259  *
7260  * Returns zero on success or negative error code.  On success all
7261  * pages which PFN is in [start, end) are allocated for the caller and
7262  * need to be freed with free_contig_range().
7263  */
7264 int alloc_contig_range(unsigned long start, unsigned long end,
7265                        unsigned migratetype)
7266 {
7267         unsigned long outer_start, outer_end;
7268         unsigned int order;
7269         int ret = 0;
7270 
7271         struct compact_control cc = {
7272                 .nr_migratepages = 0,
7273                 .order = -1,
7274                 .zone = page_zone(pfn_to_page(start)),
7275                 .mode = MIGRATE_SYNC,
7276                 .ignore_skip_hint = true,
7277                 .gfp_mask = GFP_KERNEL,
7278         };
7279         INIT_LIST_HEAD(&cc.migratepages);
7280 
7281         /*
7282          * What we do here is we mark all pageblocks in range as
7283          * MIGRATE_ISOLATE.  Because pageblock and max order pages may
7284          * have different sizes, and due to the way page allocator
7285          * work, we align the range to biggest of the two pages so
7286          * that page allocator won't try to merge buddies from
7287          * different pageblocks and change MIGRATE_ISOLATE to some
7288          * other migration type.
7289          *
7290          * Once the pageblocks are marked as MIGRATE_ISOLATE, we
7291          * migrate the pages from an unaligned range (ie. pages that
7292          * we are interested in).  This will put all the pages in
7293          * range back to page allocator as MIGRATE_ISOLATE.
7294          *
7295          * When this is done, we take the pages in range from page
7296          * allocator removing them from the buddy system.  This way
7297          * page allocator will never consider using them.
7298          *
7299          * This lets us mark the pageblocks back as
7300          * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
7301          * aligned range but not in the unaligned, original range are
7302          * put back to page allocator so that buddy can use them.
7303          */
7304 
7305         ret = start_isolate_page_range(pfn_max_align_down(start),
7306                                        pfn_max_align_up(end), migratetype,
7307                                        false);
7308         if (ret)
7309                 return ret;
7310 
7311         /*
7312          * In case of -EBUSY, we'd like to know which page causes problem.
7313          * So, just fall through. We will check it in test_pages_isolated().
7314          */
7315         ret = __alloc_contig_migrate_range(&cc, start, end);
7316         if (ret && ret != -EBUSY)
7317                 goto done;
7318 
7319         /*
7320          * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
7321          * aligned blocks that are marked as MIGRATE_ISOLATE.  What's
7322          * more, all pages in [start, end) are free in page allocator.
7323          * What we are going to do is to allocate all pages from
7324          * [start, end) (that is remove them from page allocator).
7325          *
7326          * The only problem is that pages at the beginning and at the
7327          * end of interesting range may be not aligned with pages that
7328          * page allocator holds, ie. they can be part of higher order
7329          * pages.  Because of this, we reserve the bigger range and
7330          * once this is done free the pages we are not interested in.
7331          *
7332          * We don't have to hold zone->lock here because the pages are
7333          * isolated thus they won't get removed from buddy.
7334          */
7335 
7336         lru_add_drain_all();
7337         drain_all_pages(cc.zone);
7338 
7339         order = 0;
7340         outer_start = start;
7341         while (!PageBuddy(pfn_to_page(outer_start))) {
7342                 if (++order >= MAX_ORDER) {
7343                         outer_start = start;
7344                         break;
7345                 }
7346                 outer_start &= ~0UL << order;
7347         }
7348 
7349         if (outer_start != start) {
7350                 order = page_order(pfn_to_page(outer_start));
7351 
7352                 /*
7353                  * outer_start page could be small order buddy page and
7354                  * it doesn't include start page. Adjust outer_start
7355                  * in this case to report failed page properly
7356                  * on tracepoint in test_pages_isolated()
7357                  */
7358                 if (outer_start + (1UL << order) <= start)
7359                         outer_start = start;
7360         }
7361 
7362         /* Make sure the range is really isolated. */
7363         if (test_pages_isolated(outer_start, end, false)) {
7364                 pr_info("%s: [%lx, %lx) PFNs busy\n",
7365                         __func__, outer_start, end);
7366                 ret = -EBUSY;
7367                 goto done;
7368         }
7369 
7370         /* Grab isolated pages from freelists. */
7371         outer_end = isolate_freepages_range(&cc, outer_start, end);
7372         if (!outer_end) {
7373                 ret = -EBUSY;
7374                 goto done;
7375         }
7376 
7377         /* Free head and tail (if any) */
7378         if (start != outer_start)
7379                 free_contig_range(outer_start, start - outer_start);
7380         if (end != outer_end)
7381                 free_contig_range(end, outer_end - end);
7382 
7383 done:
7384         undo_isolate_page_range(pfn_max_align_down(start),
7385                                 pfn_max_align_up(end), migratetype);
7386         return ret;
7387 }
7388 
7389 void free_contig_range(unsigned long pfn, unsigned nr_pages)
7390 {
7391         unsigned int count = 0;
7392 
7393         for (; nr_pages--; pfn++) {
7394                 struct page *page = pfn_to_page(pfn);
7395 
7396                 count += page_count(page) != 1;
7397                 __free_page(page);
7398         }
7399         WARN(count != 0, "%d pages are still in use!\n", count);
7400 }
7401 #endif
7402 
7403 #ifdef CONFIG_MEMORY_HOTPLUG
7404 /*
7405  * The zone indicated has a new number of managed_pages; batch sizes and percpu
7406  * page high values need to be recalulated.
7407  */
7408 void __meminit zone_pcp_update(struct zone *zone)
7409 {
7410         unsigned cpu;
7411         mutex_lock(&pcp_batch_high_lock);
7412         for_each_possible_cpu(cpu)
7413                 pageset_set_high_and_batch(zone,
7414                                 per_cpu_ptr(zone->pageset, cpu));
7415         mutex_unlock(&pcp_batch_high_lock);
7416 }
7417 #endif
7418 
7419 void zone_pcp_reset(struct zone *zone)
7420 {
7421         unsigned long flags;
7422         int cpu;
7423         struct per_cpu_pageset *pset;
7424 
7425         /* avoid races with drain_pages()  */
7426         local_irq_save(flags);
7427         if (zone->pageset != &boot_pageset) {
7428                 for_each_online_cpu(cpu) {
7429                         pset = per_cpu_ptr(zone->pageset, cpu);
7430                         drain_zonestat(zone, pset);
7431                 }
7432                 free_percpu(zone->pageset);
7433                 zone->pageset = &boot_pageset;
7434         }
7435         local_irq_restore(flags);
7436 }
7437 
7438 #ifdef CONFIG_MEMORY_HOTREMOVE
7439 /*
7440  * All pages in the range must be in a single zone and isolated
7441  * before calling this.
7442  */
7443 void
7444 __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
7445 {
7446         struct page *page;
7447         struct zone *zone;
7448         unsigned int order, i;
7449         unsigned long pfn;
7450         unsigned long flags;
7451         /* find the first valid pfn */
7452         for (pfn = start_pfn; pfn < end_pfn; pfn++)
7453                 if (pfn_valid(pfn))
7454                         break;
7455         if (pfn == end_pfn)
7456                 return;
7457         zone = page_zone(pfn_to_page(pfn));
7458         spin_lock_irqsave(&zone->lock, flags);
7459         pfn = start_pfn;
7460         while (pfn < end_pfn) {
7461                 if (!pfn_valid(pfn)) {
7462                         pfn++;
7463                         continue;
7464                 }
7465                 page = pfn_to_page(pfn);
7466                 /*
7467                  * The HWPoisoned page may be not in buddy system, and
7468                  * page_count() is not 0.
7469                  */
7470                 if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
7471                         pfn++;
7472                         SetPageReserved(page);
7473                         continue;
7474                 }
7475 
7476                 BUG_ON(page_count(page));
7477                 BUG_ON(!PageBuddy(page));
7478                 order = page_order(page);
7479 #ifdef CONFIG_DEBUG_VM
7480                 pr_info("remove from free list %lx %d %lx\n",
7481                         pfn, 1 << order, end_pfn);
7482 #endif
7483                 list_del(&page->lru);
7484                 rmv_page_order(page);
7485                 zone->free_area[order].nr_free--;
7486                 for (i = 0; i < (1 << order); i++)
7487                         SetPageReserved((page+i));
7488                 pfn += (1 << order);
7489         }
7490         spin_unlock_irqrestore(&zone->lock, flags);
7491 }
7492 #endif
7493 
7494 bool is_free_buddy_page(struct page *page)
7495 {
7496         struct zone *zone = page_zone(page);
7497         unsigned long pfn = page_to_pfn(page);
7498         unsigned long flags;
7499         unsigned int order;
7500 
7501         spin_lock_irqsave(&zone->lock, flags);
7502         for (order = 0; order < MAX_ORDER; order++) {
7503                 struct page *page_head = page - (pfn & ((1 << order) - 1));
7504 
7505                 if (PageBuddy(page_head) && page_order(page_head) >= order)
7506                         break;
7507         }
7508         spin_unlock_irqrestore(&zone->lock, flags);
7509 
7510         return order < MAX_ORDER;
7511 }
7512 

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