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Linux/mm/page_alloc.c

  1 /*
  2  *  linux/mm/page_alloc.c
  3  *
  4  *  Manages the free list, the system allocates free pages here.
  5  *  Note that kmalloc() lives in slab.c
  6  *
  7  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  8  *  Swap reorganised 29.12.95, Stephen Tweedie
  9  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 10  *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
 11  *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
 12  *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
 13  *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
 14  *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
 15  */
 16 
 17 #include <linux/stddef.h>
 18 #include <linux/mm.h>
 19 #include <linux/swap.h>
 20 #include <linux/interrupt.h>
 21 #include <linux/pagemap.h>
 22 #include <linux/jiffies.h>
 23 #include <linux/bootmem.h>
 24 #include <linux/memblock.h>
 25 #include <linux/compiler.h>
 26 #include <linux/kernel.h>
 27 #include <linux/kmemcheck.h>
 28 #include <linux/module.h>
 29 #include <linux/suspend.h>
 30 #include <linux/pagevec.h>
 31 #include <linux/blkdev.h>
 32 #include <linux/slab.h>
 33 #include <linux/ratelimit.h>
 34 #include <linux/oom.h>
 35 #include <linux/notifier.h>
 36 #include <linux/topology.h>
 37 #include <linux/sysctl.h>
 38 #include <linux/cpu.h>
 39 #include <linux/cpuset.h>
 40 #include <linux/memory_hotplug.h>
 41 #include <linux/nodemask.h>
 42 #include <linux/vmalloc.h>
 43 #include <linux/vmstat.h>
 44 #include <linux/mempolicy.h>
 45 #include <linux/stop_machine.h>
 46 #include <linux/sort.h>
 47 #include <linux/pfn.h>
 48 #include <linux/backing-dev.h>
 49 #include <linux/fault-inject.h>
 50 #include <linux/page-isolation.h>
 51 #include <linux/page_cgroup.h>
 52 #include <linux/debugobjects.h>
 53 #include <linux/kmemleak.h>
 54 #include <linux/compaction.h>
 55 #include <trace/events/kmem.h>
 56 #include <linux/ftrace_event.h>
 57 #include <linux/memcontrol.h>
 58 #include <linux/prefetch.h>
 59 #include <linux/mm_inline.h>
 60 #include <linux/migrate.h>
 61 #include <linux/page-debug-flags.h>
 62 #include <linux/hugetlb.h>
 63 #include <linux/sched/rt.h>
 64 
 65 #include <asm/sections.h>
 66 #include <asm/tlbflush.h>
 67 #include <asm/div64.h>
 68 #include "internal.h"
 69 
 70 /* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
 71 static DEFINE_MUTEX(pcp_batch_high_lock);
 72 
 73 #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
 74 DEFINE_PER_CPU(int, numa_node);
 75 EXPORT_PER_CPU_SYMBOL(numa_node);
 76 #endif
 77 
 78 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
 79 /*
 80  * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
 81  * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
 82  * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
 83  * defined in <linux/topology.h>.
 84  */
 85 DEFINE_PER_CPU(int, _numa_mem_);                /* Kernel "local memory" node */
 86 EXPORT_PER_CPU_SYMBOL(_numa_mem_);
 87 #endif
 88 
 89 /*
 90  * Array of node states.
 91  */
 92 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
 93         [N_POSSIBLE] = NODE_MASK_ALL,
 94         [N_ONLINE] = { { [0] = 1UL } },
 95 #ifndef CONFIG_NUMA
 96         [N_NORMAL_MEMORY] = { { [0] = 1UL } },
 97 #ifdef CONFIG_HIGHMEM
 98         [N_HIGH_MEMORY] = { { [0] = 1UL } },
 99 #endif
100 #ifdef CONFIG_MOVABLE_NODE
101         [N_MEMORY] = { { [0] = 1UL } },
102 #endif
103         [N_CPU] = { { [0] = 1UL } },
104 #endif  /* NUMA */
105 };
106 EXPORT_SYMBOL(node_states);
107 
108 /* Protect totalram_pages and zone->managed_pages */
109 static DEFINE_SPINLOCK(managed_page_count_lock);
110 
111 unsigned long totalram_pages __read_mostly;
112 unsigned long totalreserve_pages __read_mostly;
113 /*
114  * When calculating the number of globally allowed dirty pages, there
115  * is a certain number of per-zone reserves that should not be
116  * considered dirtyable memory.  This is the sum of those reserves
117  * over all existing zones that contribute dirtyable memory.
118  */
119 unsigned long dirty_balance_reserve __read_mostly;
120 
121 int percpu_pagelist_fraction;
122 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
123 
124 #ifdef CONFIG_PM_SLEEP
125 /*
126  * The following functions are used by the suspend/hibernate code to temporarily
127  * change gfp_allowed_mask in order to avoid using I/O during memory allocations
128  * while devices are suspended.  To avoid races with the suspend/hibernate code,
129  * they should always be called with pm_mutex held (gfp_allowed_mask also should
130  * only be modified with pm_mutex held, unless the suspend/hibernate code is
131  * guaranteed not to run in parallel with that modification).
132  */
133 
134 static gfp_t saved_gfp_mask;
135 
136 void pm_restore_gfp_mask(void)
137 {
138         WARN_ON(!mutex_is_locked(&pm_mutex));
139         if (saved_gfp_mask) {
140                 gfp_allowed_mask = saved_gfp_mask;
141                 saved_gfp_mask = 0;
142         }
143 }
144 
145 void pm_restrict_gfp_mask(void)
146 {
147         WARN_ON(!mutex_is_locked(&pm_mutex));
148         WARN_ON(saved_gfp_mask);
149         saved_gfp_mask = gfp_allowed_mask;
150         gfp_allowed_mask &= ~GFP_IOFS;
151 }
152 
153 bool pm_suspended_storage(void)
154 {
155         if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS)
156                 return false;
157         return true;
158 }
159 #endif /* CONFIG_PM_SLEEP */
160 
161 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
162 int pageblock_order __read_mostly;
163 #endif
164 
165 static void __free_pages_ok(struct page *page, unsigned int order);
166 
167 /*
168  * results with 256, 32 in the lowmem_reserve sysctl:
169  *      1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
170  *      1G machine -> (16M dma, 784M normal, 224M high)
171  *      NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
172  *      HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
173  *      HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
174  *
175  * TBD: should special case ZONE_DMA32 machines here - in those we normally
176  * don't need any ZONE_NORMAL reservation
177  */
178 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
179 #ifdef CONFIG_ZONE_DMA
180          256,
181 #endif
182 #ifdef CONFIG_ZONE_DMA32
183          256,
184 #endif
185 #ifdef CONFIG_HIGHMEM
186          32,
187 #endif
188          32,
189 };
190 
191 EXPORT_SYMBOL(totalram_pages);
192 
193 static char * const zone_names[MAX_NR_ZONES] = {
194 #ifdef CONFIG_ZONE_DMA
195          "DMA",
196 #endif
197 #ifdef CONFIG_ZONE_DMA32
198          "DMA32",
199 #endif
200          "Normal",
201 #ifdef CONFIG_HIGHMEM
202          "HighMem",
203 #endif
204          "Movable",
205 };
206 
207 int min_free_kbytes = 1024;
208 int user_min_free_kbytes = -1;
209 
210 static unsigned long __meminitdata nr_kernel_pages;
211 static unsigned long __meminitdata nr_all_pages;
212 static unsigned long __meminitdata dma_reserve;
213 
214 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
215 static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
216 static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
217 static unsigned long __initdata required_kernelcore;
218 static unsigned long __initdata required_movablecore;
219 static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
220 
221 /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
222 int movable_zone;
223 EXPORT_SYMBOL(movable_zone);
224 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
225 
226 #if MAX_NUMNODES > 1
227 int nr_node_ids __read_mostly = MAX_NUMNODES;
228 int nr_online_nodes __read_mostly = 1;
229 EXPORT_SYMBOL(nr_node_ids);
230 EXPORT_SYMBOL(nr_online_nodes);
231 #endif
232 
233 int page_group_by_mobility_disabled __read_mostly;
234 
235 void set_pageblock_migratetype(struct page *page, int migratetype)
236 {
237         if (unlikely(page_group_by_mobility_disabled &&
238                      migratetype < MIGRATE_PCPTYPES))
239                 migratetype = MIGRATE_UNMOVABLE;
240 
241         set_pageblock_flags_group(page, (unsigned long)migratetype,
242                                         PB_migrate, PB_migrate_end);
243 }
244 
245 bool oom_killer_disabled __read_mostly;
246 
247 #ifdef CONFIG_DEBUG_VM
248 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
249 {
250         int ret = 0;
251         unsigned seq;
252         unsigned long pfn = page_to_pfn(page);
253         unsigned long sp, start_pfn;
254 
255         do {
256                 seq = zone_span_seqbegin(zone);
257                 start_pfn = zone->zone_start_pfn;
258                 sp = zone->spanned_pages;
259                 if (!zone_spans_pfn(zone, pfn))
260                         ret = 1;
261         } while (zone_span_seqretry(zone, seq));
262 
263         if (ret)
264                 pr_err("page %lu outside zone [ %lu - %lu ]\n",
265                         pfn, start_pfn, start_pfn + sp);
266 
267         return ret;
268 }
269 
270 static int page_is_consistent(struct zone *zone, struct page *page)
271 {
272         if (!pfn_valid_within(page_to_pfn(page)))
273                 return 0;
274         if (zone != page_zone(page))
275                 return 0;
276 
277         return 1;
278 }
279 /*
280  * Temporary debugging check for pages not lying within a given zone.
281  */
282 static int bad_range(struct zone *zone, struct page *page)
283 {
284         if (page_outside_zone_boundaries(zone, page))
285                 return 1;
286         if (!page_is_consistent(zone, page))
287                 return 1;
288 
289         return 0;
290 }
291 #else
292 static inline int bad_range(struct zone *zone, struct page *page)
293 {
294         return 0;
295 }
296 #endif
297 
298 static void bad_page(struct page *page, char *reason, unsigned long bad_flags)
299 {
300         static unsigned long resume;
301         static unsigned long nr_shown;
302         static unsigned long nr_unshown;
303 
304         /* Don't complain about poisoned pages */
305         if (PageHWPoison(page)) {
306                 page_mapcount_reset(page); /* remove PageBuddy */
307                 return;
308         }
309 
310         /*
311          * Allow a burst of 60 reports, then keep quiet for that minute;
312          * or allow a steady drip of one report per second.
313          */
314         if (nr_shown == 60) {
315                 if (time_before(jiffies, resume)) {
316                         nr_unshown++;
317                         goto out;
318                 }
319                 if (nr_unshown) {
320                         printk(KERN_ALERT
321                               "BUG: Bad page state: %lu messages suppressed\n",
322                                 nr_unshown);
323                         nr_unshown = 0;
324                 }
325                 nr_shown = 0;
326         }
327         if (nr_shown++ == 0)
328                 resume = jiffies + 60 * HZ;
329 
330         printk(KERN_ALERT "BUG: Bad page state in process %s  pfn:%05lx\n",
331                 current->comm, page_to_pfn(page));
332         dump_page_badflags(page, reason, bad_flags);
333 
334         print_modules();
335         dump_stack();
336 out:
337         /* Leave bad fields for debug, except PageBuddy could make trouble */
338         page_mapcount_reset(page); /* remove PageBuddy */
339         add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
340 }
341 
342 /*
343  * Higher-order pages are called "compound pages".  They are structured thusly:
344  *
345  * The first PAGE_SIZE page is called the "head page".
346  *
347  * The remaining PAGE_SIZE pages are called "tail pages".
348  *
349  * All pages have PG_compound set.  All tail pages have their ->first_page
350  * pointing at the head page.
351  *
352  * The first tail page's ->lru.next holds the address of the compound page's
353  * put_page() function.  Its ->lru.prev holds the order of allocation.
354  * This usage means that zero-order pages may not be compound.
355  */
356 
357 static void free_compound_page(struct page *page)
358 {
359         __free_pages_ok(page, compound_order(page));
360 }
361 
362 void prep_compound_page(struct page *page, unsigned long order)
363 {
364         int i;
365         int nr_pages = 1 << order;
366 
367         set_compound_page_dtor(page, free_compound_page);
368         set_compound_order(page, order);
369         __SetPageHead(page);
370         for (i = 1; i < nr_pages; i++) {
371                 struct page *p = page + i;
372                 set_page_count(p, 0);
373                 p->first_page = page;
374                 /* Make sure p->first_page is always valid for PageTail() */
375                 smp_wmb();
376                 __SetPageTail(p);
377         }
378 }
379 
380 /* update __split_huge_page_refcount if you change this function */
381 static int destroy_compound_page(struct page *page, unsigned long order)
382 {
383         int i;
384         int nr_pages = 1 << order;
385         int bad = 0;
386 
387         if (unlikely(compound_order(page) != order)) {
388                 bad_page(page, "wrong compound order", 0);
389                 bad++;
390         }
391 
392         __ClearPageHead(page);
393 
394         for (i = 1; i < nr_pages; i++) {
395                 struct page *p = page + i;
396 
397                 if (unlikely(!PageTail(p))) {
398                         bad_page(page, "PageTail not set", 0);
399                         bad++;
400                 } else if (unlikely(p->first_page != page)) {
401                         bad_page(page, "first_page not consistent", 0);
402                         bad++;
403                 }
404                 __ClearPageTail(p);
405         }
406 
407         return bad;
408 }
409 
410 static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
411 {
412         int i;
413 
414         /*
415          * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
416          * and __GFP_HIGHMEM from hard or soft interrupt context.
417          */
418         VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
419         for (i = 0; i < (1 << order); i++)
420                 clear_highpage(page + i);
421 }
422 
423 #ifdef CONFIG_DEBUG_PAGEALLOC
424 unsigned int _debug_guardpage_minorder;
425 
426 static int __init debug_guardpage_minorder_setup(char *buf)
427 {
428         unsigned long res;
429 
430         if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
431                 printk(KERN_ERR "Bad debug_guardpage_minorder value\n");
432                 return 0;
433         }
434         _debug_guardpage_minorder = res;
435         printk(KERN_INFO "Setting debug_guardpage_minorder to %lu\n", res);
436         return 0;
437 }
438 __setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup);
439 
440 static inline void set_page_guard_flag(struct page *page)
441 {
442         __set_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
443 }
444 
445 static inline void clear_page_guard_flag(struct page *page)
446 {
447         __clear_bit(PAGE_DEBUG_FLAG_GUARD, &page->debug_flags);
448 }
449 #else
450 static inline void set_page_guard_flag(struct page *page) { }
451 static inline void clear_page_guard_flag(struct page *page) { }
452 #endif
453 
454 static inline void set_page_order(struct page *page, int order)
455 {
456         set_page_private(page, order);
457         __SetPageBuddy(page);
458 }
459 
460 static inline void rmv_page_order(struct page *page)
461 {
462         __ClearPageBuddy(page);
463         set_page_private(page, 0);
464 }
465 
466 /*
467  * Locate the struct page for both the matching buddy in our
468  * pair (buddy1) and the combined O(n+1) page they form (page).
469  *
470  * 1) Any buddy B1 will have an order O twin B2 which satisfies
471  * the following equation:
472  *     B2 = B1 ^ (1 << O)
473  * For example, if the starting buddy (buddy2) is #8 its order
474  * 1 buddy is #10:
475  *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
476  *
477  * 2) Any buddy B will have an order O+1 parent P which
478  * satisfies the following equation:
479  *     P = B & ~(1 << O)
480  *
481  * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
482  */
483 static inline unsigned long
484 __find_buddy_index(unsigned long page_idx, unsigned int order)
485 {
486         return page_idx ^ (1 << order);
487 }
488 
489 /*
490  * This function checks whether a page is free && is the buddy
491  * we can do coalesce a page and its buddy if
492  * (a) the buddy is not in a hole &&
493  * (b) the buddy is in the buddy system &&
494  * (c) a page and its buddy have the same order &&
495  * (d) a page and its buddy are in the same zone.
496  *
497  * For recording whether a page is in the buddy system, we set ->_mapcount
498  * PAGE_BUDDY_MAPCOUNT_VALUE.
499  * Setting, clearing, and testing _mapcount PAGE_BUDDY_MAPCOUNT_VALUE is
500  * serialized by zone->lock.
501  *
502  * For recording page's order, we use page_private(page).
503  */
504 static inline int page_is_buddy(struct page *page, struct page *buddy,
505                                                                 int order)
506 {
507         if (!pfn_valid_within(page_to_pfn(buddy)))
508                 return 0;
509 
510         if (page_zone_id(page) != page_zone_id(buddy))
511                 return 0;
512 
513         if (page_is_guard(buddy) && page_order(buddy) == order) {
514                 VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
515                 return 1;
516         }
517 
518         if (PageBuddy(buddy) && page_order(buddy) == order) {
519                 VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
520                 return 1;
521         }
522         return 0;
523 }
524 
525 /*
526  * Freeing function for a buddy system allocator.
527  *
528  * The concept of a buddy system is to maintain direct-mapped table
529  * (containing bit values) for memory blocks of various "orders".
530  * The bottom level table contains the map for the smallest allocatable
531  * units of memory (here, pages), and each level above it describes
532  * pairs of units from the levels below, hence, "buddies".
533  * At a high level, all that happens here is marking the table entry
534  * at the bottom level available, and propagating the changes upward
535  * as necessary, plus some accounting needed to play nicely with other
536  * parts of the VM system.
537  * At each level, we keep a list of pages, which are heads of continuous
538  * free pages of length of (1 << order) and marked with _mapcount
539  * PAGE_BUDDY_MAPCOUNT_VALUE. Page's order is recorded in page_private(page)
540  * field.
541  * So when we are allocating or freeing one, we can derive the state of the
542  * other.  That is, if we allocate a small block, and both were
543  * free, the remainder of the region must be split into blocks.
544  * If a block is freed, and its buddy is also free, then this
545  * triggers coalescing into a block of larger size.
546  *
547  * -- nyc
548  */
549 
550 static inline void __free_one_page(struct page *page,
551                 struct zone *zone, unsigned int order,
552                 int migratetype)
553 {
554         unsigned long page_idx;
555         unsigned long combined_idx;
556         unsigned long uninitialized_var(buddy_idx);
557         struct page *buddy;
558 
559         VM_BUG_ON(!zone_is_initialized(zone));
560 
561         if (unlikely(PageCompound(page)))
562                 if (unlikely(destroy_compound_page(page, order)))
563                         return;
564 
565         VM_BUG_ON(migratetype == -1);
566 
567         page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
568 
569         VM_BUG_ON_PAGE(page_idx & ((1 << order) - 1), page);
570         VM_BUG_ON_PAGE(bad_range(zone, page), page);
571 
572         while (order < MAX_ORDER-1) {
573                 buddy_idx = __find_buddy_index(page_idx, order);
574                 buddy = page + (buddy_idx - page_idx);
575                 if (!page_is_buddy(page, buddy, order))
576                         break;
577                 /*
578                  * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
579                  * merge with it and move up one order.
580                  */
581                 if (page_is_guard(buddy)) {
582                         clear_page_guard_flag(buddy);
583                         set_page_private(page, 0);
584                         __mod_zone_freepage_state(zone, 1 << order,
585                                                   migratetype);
586                 } else {
587                         list_del(&buddy->lru);
588                         zone->free_area[order].nr_free--;
589                         rmv_page_order(buddy);
590                 }
591                 combined_idx = buddy_idx & page_idx;
592                 page = page + (combined_idx - page_idx);
593                 page_idx = combined_idx;
594                 order++;
595         }
596         set_page_order(page, order);
597 
598         /*
599          * If this is not the largest possible page, check if the buddy
600          * of the next-highest order is free. If it is, it's possible
601          * that pages are being freed that will coalesce soon. In case,
602          * that is happening, add the free page to the tail of the list
603          * so it's less likely to be used soon and more likely to be merged
604          * as a higher order page
605          */
606         if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
607                 struct page *higher_page, *higher_buddy;
608                 combined_idx = buddy_idx & page_idx;
609                 higher_page = page + (combined_idx - page_idx);
610                 buddy_idx = __find_buddy_index(combined_idx, order + 1);
611                 higher_buddy = higher_page + (buddy_idx - combined_idx);
612                 if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
613                         list_add_tail(&page->lru,
614                                 &zone->free_area[order].free_list[migratetype]);
615                         goto out;
616                 }
617         }
618 
619         list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
620 out:
621         zone->free_area[order].nr_free++;
622 }
623 
624 static inline int free_pages_check(struct page *page)
625 {
626         char *bad_reason = NULL;
627         unsigned long bad_flags = 0;
628 
629         if (unlikely(page_mapcount(page)))
630                 bad_reason = "nonzero mapcount";
631         if (unlikely(page->mapping != NULL))
632                 bad_reason = "non-NULL mapping";
633         if (unlikely(atomic_read(&page->_count) != 0))
634                 bad_reason = "nonzero _count";
635         if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
636                 bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
637                 bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
638         }
639         if (unlikely(mem_cgroup_bad_page_check(page)))
640                 bad_reason = "cgroup check failed";
641         if (unlikely(bad_reason)) {
642                 bad_page(page, bad_reason, bad_flags);
643                 return 1;
644         }
645         page_cpupid_reset_last(page);
646         if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
647                 page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
648         return 0;
649 }
650 
651 /*
652  * Frees a number of pages from the PCP lists
653  * Assumes all pages on list are in same zone, and of same order.
654  * count is the number of pages to free.
655  *
656  * If the zone was previously in an "all pages pinned" state then look to
657  * see if this freeing clears that state.
658  *
659  * And clear the zone's pages_scanned counter, to hold off the "all pages are
660  * pinned" detection logic.
661  */
662 static void free_pcppages_bulk(struct zone *zone, int count,
663                                         struct per_cpu_pages *pcp)
664 {
665         int migratetype = 0;
666         int batch_free = 0;
667         int to_free = count;
668 
669         spin_lock(&zone->lock);
670         zone->pages_scanned = 0;
671 
672         while (to_free) {
673                 struct page *page;
674                 struct list_head *list;
675 
676                 /*
677                  * Remove pages from lists in a round-robin fashion. A
678                  * batch_free count is maintained that is incremented when an
679                  * empty list is encountered.  This is so more pages are freed
680                  * off fuller lists instead of spinning excessively around empty
681                  * lists
682                  */
683                 do {
684                         batch_free++;
685                         if (++migratetype == MIGRATE_PCPTYPES)
686                                 migratetype = 0;
687                         list = &pcp->lists[migratetype];
688                 } while (list_empty(list));
689 
690                 /* This is the only non-empty list. Free them all. */
691                 if (batch_free == MIGRATE_PCPTYPES)
692                         batch_free = to_free;
693 
694                 do {
695                         int mt; /* migratetype of the to-be-freed page */
696 
697                         page = list_entry(list->prev, struct page, lru);
698                         /* must delete as __free_one_page list manipulates */
699                         list_del(&page->lru);
700                         mt = get_freepage_migratetype(page);
701                         /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
702                         __free_one_page(page, zone, 0, mt);
703                         trace_mm_page_pcpu_drain(page, 0, mt);
704                         if (likely(!is_migrate_isolate_page(page))) {
705                                 __mod_zone_page_state(zone, NR_FREE_PAGES, 1);
706                                 if (is_migrate_cma(mt))
707                                         __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
708                         }
709                 } while (--to_free && --batch_free && !list_empty(list));
710         }
711         spin_unlock(&zone->lock);
712 }
713 
714 static void free_one_page(struct zone *zone, struct page *page, int order,
715                                 int migratetype)
716 {
717         spin_lock(&zone->lock);
718         zone->pages_scanned = 0;
719 
720         __free_one_page(page, zone, order, migratetype);
721         if (unlikely(!is_migrate_isolate(migratetype)))
722                 __mod_zone_freepage_state(zone, 1 << order, migratetype);
723         spin_unlock(&zone->lock);
724 }
725 
726 static bool free_pages_prepare(struct page *page, unsigned int order)
727 {
728         int i;
729         int bad = 0;
730 
731         trace_mm_page_free(page, order);
732         kmemcheck_free_shadow(page, order);
733 
734         if (PageAnon(page))
735                 page->mapping = NULL;
736         for (i = 0; i < (1 << order); i++)
737                 bad += free_pages_check(page + i);
738         if (bad)
739                 return false;
740 
741         if (!PageHighMem(page)) {
742                 debug_check_no_locks_freed(page_address(page),
743                                            PAGE_SIZE << order);
744                 debug_check_no_obj_freed(page_address(page),
745                                            PAGE_SIZE << order);
746         }
747         arch_free_page(page, order);
748         kernel_map_pages(page, 1 << order, 0);
749 
750         return true;
751 }
752 
753 static void __free_pages_ok(struct page *page, unsigned int order)
754 {
755         unsigned long flags;
756         int migratetype;
757 
758         if (!free_pages_prepare(page, order))
759                 return;
760 
761         local_irq_save(flags);
762         __count_vm_events(PGFREE, 1 << order);
763         migratetype = get_pageblock_migratetype(page);
764         set_freepage_migratetype(page, migratetype);
765         free_one_page(page_zone(page), page, order, migratetype);
766         local_irq_restore(flags);
767 }
768 
769 void __init __free_pages_bootmem(struct page *page, unsigned int order)
770 {
771         unsigned int nr_pages = 1 << order;
772         struct page *p = page;
773         unsigned int loop;
774 
775         prefetchw(p);
776         for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
777                 prefetchw(p + 1);
778                 __ClearPageReserved(p);
779                 set_page_count(p, 0);
780         }
781         __ClearPageReserved(p);
782         set_page_count(p, 0);
783 
784         page_zone(page)->managed_pages += nr_pages;
785         set_page_refcounted(page);
786         __free_pages(page, order);
787 }
788 
789 #ifdef CONFIG_CMA
790 /* Free whole pageblock and set its migration type to MIGRATE_CMA. */
791 void __init init_cma_reserved_pageblock(struct page *page)
792 {
793         unsigned i = pageblock_nr_pages;
794         struct page *p = page;
795 
796         do {
797                 __ClearPageReserved(p);
798                 set_page_count(p, 0);
799         } while (++p, --i);
800 
801         set_page_refcounted(page);
802         set_pageblock_migratetype(page, MIGRATE_CMA);
803         __free_pages(page, pageblock_order);
804         adjust_managed_page_count(page, pageblock_nr_pages);
805 }
806 #endif
807 
808 /*
809  * The order of subdivision here is critical for the IO subsystem.
810  * Please do not alter this order without good reasons and regression
811  * testing. Specifically, as large blocks of memory are subdivided,
812  * the order in which smaller blocks are delivered depends on the order
813  * they're subdivided in this function. This is the primary factor
814  * influencing the order in which pages are delivered to the IO
815  * subsystem according to empirical testing, and this is also justified
816  * by considering the behavior of a buddy system containing a single
817  * large block of memory acted on by a series of small allocations.
818  * This behavior is a critical factor in sglist merging's success.
819  *
820  * -- nyc
821  */
822 static inline void expand(struct zone *zone, struct page *page,
823         int low, int high, struct free_area *area,
824         int migratetype)
825 {
826         unsigned long size = 1 << high;
827 
828         while (high > low) {
829                 area--;
830                 high--;
831                 size >>= 1;
832                 VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
833 
834 #ifdef CONFIG_DEBUG_PAGEALLOC
835                 if (high < debug_guardpage_minorder()) {
836                         /*
837                          * Mark as guard pages (or page), that will allow to
838                          * merge back to allocator when buddy will be freed.
839                          * Corresponding page table entries will not be touched,
840                          * pages will stay not present in virtual address space
841                          */
842                         INIT_LIST_HEAD(&page[size].lru);
843                         set_page_guard_flag(&page[size]);
844                         set_page_private(&page[size], high);
845                         /* Guard pages are not available for any usage */
846                         __mod_zone_freepage_state(zone, -(1 << high),
847                                                   migratetype);
848                         continue;
849                 }
850 #endif
851                 list_add(&page[size].lru, &area->free_list[migratetype]);
852                 area->nr_free++;
853                 set_page_order(&page[size], high);
854         }
855 }
856 
857 /*
858  * This page is about to be returned from the page allocator
859  */
860 static inline int check_new_page(struct page *page)
861 {
862         char *bad_reason = NULL;
863         unsigned long bad_flags = 0;
864 
865         if (unlikely(page_mapcount(page)))
866                 bad_reason = "nonzero mapcount";
867         if (unlikely(page->mapping != NULL))
868                 bad_reason = "non-NULL mapping";
869         if (unlikely(atomic_read(&page->_count) != 0))
870                 bad_reason = "nonzero _count";
871         if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
872                 bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
873                 bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
874         }
875         if (unlikely(mem_cgroup_bad_page_check(page)))
876                 bad_reason = "cgroup check failed";
877         if (unlikely(bad_reason)) {
878                 bad_page(page, bad_reason, bad_flags);
879                 return 1;
880         }
881         return 0;
882 }
883 
884 static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
885 {
886         int i;
887 
888         for (i = 0; i < (1 << order); i++) {
889                 struct page *p = page + i;
890                 if (unlikely(check_new_page(p)))
891                         return 1;
892         }
893 
894         set_page_private(page, 0);
895         set_page_refcounted(page);
896 
897         arch_alloc_page(page, order);
898         kernel_map_pages(page, 1 << order, 1);
899 
900         if (gfp_flags & __GFP_ZERO)
901                 prep_zero_page(page, order, gfp_flags);
902 
903         if (order && (gfp_flags & __GFP_COMP))
904                 prep_compound_page(page, order);
905 
906         return 0;
907 }
908 
909 /*
910  * Go through the free lists for the given migratetype and remove
911  * the smallest available page from the freelists
912  */
913 static inline
914 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
915                                                 int migratetype)
916 {
917         unsigned int current_order;
918         struct free_area *area;
919         struct page *page;
920 
921         /* Find a page of the appropriate size in the preferred list */
922         for (current_order = order; current_order < MAX_ORDER; ++current_order) {
923                 area = &(zone->free_area[current_order]);
924                 if (list_empty(&area->free_list[migratetype]))
925                         continue;
926 
927                 page = list_entry(area->free_list[migratetype].next,
928                                                         struct page, lru);
929                 list_del(&page->lru);
930                 rmv_page_order(page);
931                 area->nr_free--;
932                 expand(zone, page, order, current_order, area, migratetype);
933                 return page;
934         }
935 
936         return NULL;
937 }
938 
939 
940 /*
941  * This array describes the order lists are fallen back to when
942  * the free lists for the desirable migrate type are depleted
943  */
944 static int fallbacks[MIGRATE_TYPES][4] = {
945         [MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,     MIGRATE_RESERVE },
946         [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,     MIGRATE_RESERVE },
947 #ifdef CONFIG_CMA
948         [MIGRATE_MOVABLE]     = { MIGRATE_CMA,         MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
949         [MIGRATE_CMA]         = { MIGRATE_RESERVE }, /* Never used */
950 #else
951         [MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE,   MIGRATE_RESERVE },
952 #endif
953         [MIGRATE_RESERVE]     = { MIGRATE_RESERVE }, /* Never used */
954 #ifdef CONFIG_MEMORY_ISOLATION
955         [MIGRATE_ISOLATE]     = { MIGRATE_RESERVE }, /* Never used */
956 #endif
957 };
958 
959 /*
960  * Move the free pages in a range to the free lists of the requested type.
961  * Note that start_page and end_pages are not aligned on a pageblock
962  * boundary. If alignment is required, use move_freepages_block()
963  */
964 int move_freepages(struct zone *zone,
965                           struct page *start_page, struct page *end_page,
966                           int migratetype)
967 {
968         struct page *page;
969         unsigned long order;
970         int pages_moved = 0;
971 
972 #ifndef CONFIG_HOLES_IN_ZONE
973         /*
974          * page_zone is not safe to call in this context when
975          * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
976          * anyway as we check zone boundaries in move_freepages_block().
977          * Remove at a later date when no bug reports exist related to
978          * grouping pages by mobility
979          */
980         BUG_ON(page_zone(start_page) != page_zone(end_page));
981 #endif
982 
983         for (page = start_page; page <= end_page;) {
984                 /* Make sure we are not inadvertently changing nodes */
985                 VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
986 
987                 if (!pfn_valid_within(page_to_pfn(page))) {
988                         page++;
989                         continue;
990                 }
991 
992                 if (!PageBuddy(page)) {
993                         page++;
994                         continue;
995                 }
996 
997                 order = page_order(page);
998                 list_move(&page->lru,
999                           &zone->free_area[order].free_list[migratetype]);
1000                 set_freepage_migratetype(page, migratetype);
1001                 page += 1 << order;
1002                 pages_moved += 1 << order;
1003         }
1004 
1005         return pages_moved;
1006 }
1007 
1008 int move_freepages_block(struct zone *zone, struct page *page,
1009                                 int migratetype)
1010 {
1011         unsigned long start_pfn, end_pfn;
1012         struct page *start_page, *end_page;
1013 
1014         start_pfn = page_to_pfn(page);
1015         start_pfn = start_pfn & ~(pageblock_nr_pages-1);
1016         start_page = pfn_to_page(start_pfn);
1017         end_page = start_page + pageblock_nr_pages - 1;
1018         end_pfn = start_pfn + pageblock_nr_pages - 1;
1019 
1020         /* Do not cross zone boundaries */
1021         if (!zone_spans_pfn(zone, start_pfn))
1022                 start_page = page;
1023         if (!zone_spans_pfn(zone, end_pfn))
1024                 return 0;
1025 
1026         return move_freepages(zone, start_page, end_page, migratetype);
1027 }
1028 
1029 static void change_pageblock_range(struct page *pageblock_page,
1030                                         int start_order, int migratetype)
1031 {
1032         int nr_pageblocks = 1 << (start_order - pageblock_order);
1033 
1034         while (nr_pageblocks--) {
1035                 set_pageblock_migratetype(pageblock_page, migratetype);
1036                 pageblock_page += pageblock_nr_pages;
1037         }
1038 }
1039 
1040 /*
1041  * If breaking a large block of pages, move all free pages to the preferred
1042  * allocation list. If falling back for a reclaimable kernel allocation, be
1043  * more aggressive about taking ownership of free pages.
1044  *
1045  * On the other hand, never change migration type of MIGRATE_CMA pageblocks
1046  * nor move CMA pages to different free lists. We don't want unmovable pages
1047  * to be allocated from MIGRATE_CMA areas.
1048  *
1049  * Returns the new migratetype of the pageblock (or the same old migratetype
1050  * if it was unchanged).
1051  */
1052 static int try_to_steal_freepages(struct zone *zone, struct page *page,
1053                                   int start_type, int fallback_type)
1054 {
1055         int current_order = page_order(page);
1056 
1057         /*
1058          * When borrowing from MIGRATE_CMA, we need to release the excess
1059          * buddy pages to CMA itself.
1060          */
1061         if (is_migrate_cma(fallback_type))
1062                 return fallback_type;
1063 
1064         /* Take ownership for orders >= pageblock_order */
1065         if (current_order >= pageblock_order) {
1066                 change_pageblock_range(page, current_order, start_type);
1067                 return start_type;
1068         }
1069 
1070         if (current_order >= pageblock_order / 2 ||
1071             start_type == MIGRATE_RECLAIMABLE ||
1072             page_group_by_mobility_disabled) {
1073                 int pages;
1074 
1075                 pages = move_freepages_block(zone, page, start_type);
1076 
1077                 /* Claim the whole block if over half of it is free */
1078                 if (pages >= (1 << (pageblock_order-1)) ||
1079                                 page_group_by_mobility_disabled) {
1080 
1081                         set_pageblock_migratetype(page, start_type);
1082                         return start_type;
1083                 }
1084 
1085         }
1086 
1087         return fallback_type;
1088 }
1089 
1090 /* Remove an element from the buddy allocator from the fallback list */
1091 static inline struct page *
1092 __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
1093 {
1094         struct free_area *area;
1095         int current_order;
1096         struct page *page;
1097         int migratetype, new_type, i;
1098 
1099         /* Find the largest possible block of pages in the other list */
1100         for (current_order = MAX_ORDER-1; current_order >= order;
1101                                                 --current_order) {
1102                 for (i = 0;; i++) {
1103                         migratetype = fallbacks[start_migratetype][i];
1104 
1105                         /* MIGRATE_RESERVE handled later if necessary */
1106                         if (migratetype == MIGRATE_RESERVE)
1107                                 break;
1108 
1109                         area = &(zone->free_area[current_order]);
1110                         if (list_empty(&area->free_list[migratetype]))
1111                                 continue;
1112 
1113                         page = list_entry(area->free_list[migratetype].next,
1114                                         struct page, lru);
1115                         area->nr_free--;
1116 
1117                         new_type = try_to_steal_freepages(zone, page,
1118                                                           start_migratetype,
1119                                                           migratetype);
1120 
1121                         /* Remove the page from the freelists */
1122                         list_del(&page->lru);
1123                         rmv_page_order(page);
1124 
1125                         expand(zone, page, order, current_order, area,
1126                                new_type);
1127 
1128                         trace_mm_page_alloc_extfrag(page, order, current_order,
1129                                 start_migratetype, migratetype, new_type);
1130 
1131                         return page;
1132                 }
1133         }
1134 
1135         return NULL;
1136 }
1137 
1138 /*
1139  * Do the hard work of removing an element from the buddy allocator.
1140  * Call me with the zone->lock already held.
1141  */
1142 static struct page *__rmqueue(struct zone *zone, unsigned int order,
1143                                                 int migratetype)
1144 {
1145         struct page *page;
1146 
1147 retry_reserve:
1148         page = __rmqueue_smallest(zone, order, migratetype);
1149 
1150         if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
1151                 page = __rmqueue_fallback(zone, order, migratetype);
1152 
1153                 /*
1154                  * Use MIGRATE_RESERVE rather than fail an allocation. goto
1155                  * is used because __rmqueue_smallest is an inline function
1156                  * and we want just one call site
1157                  */
1158                 if (!page) {
1159                         migratetype = MIGRATE_RESERVE;
1160                         goto retry_reserve;
1161                 }
1162         }
1163 
1164         trace_mm_page_alloc_zone_locked(page, order, migratetype);
1165         return page;
1166 }
1167 
1168 /*
1169  * Obtain a specified number of elements from the buddy allocator, all under
1170  * a single hold of the lock, for efficiency.  Add them to the supplied list.
1171  * Returns the number of new pages which were placed at *list.
1172  */
1173 static int rmqueue_bulk(struct zone *zone, unsigned int order,
1174                         unsigned long count, struct list_head *list,
1175                         int migratetype, int cold)
1176 {
1177         int mt = migratetype, i;
1178 
1179         spin_lock(&zone->lock);
1180         for (i = 0; i < count; ++i) {
1181                 struct page *page = __rmqueue(zone, order, migratetype);
1182                 if (unlikely(page == NULL))
1183                         break;
1184 
1185                 /*
1186                  * Split buddy pages returned by expand() are received here
1187                  * in physical page order. The page is added to the callers and
1188                  * list and the list head then moves forward. From the callers
1189                  * perspective, the linked list is ordered by page number in
1190                  * some conditions. This is useful for IO devices that can
1191                  * merge IO requests if the physical pages are ordered
1192                  * properly.
1193                  */
1194                 if (likely(cold == 0))
1195                         list_add(&page->lru, list);
1196                 else
1197                         list_add_tail(&page->lru, list);
1198                 if (IS_ENABLED(CONFIG_CMA)) {
1199                         mt = get_pageblock_migratetype(page);
1200                         if (!is_migrate_cma(mt) && !is_migrate_isolate(mt))
1201                                 mt = migratetype;
1202                 }
1203                 set_freepage_migratetype(page, mt);
1204                 list = &page->lru;
1205                 if (is_migrate_cma(mt))
1206                         __mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
1207                                               -(1 << order));
1208         }
1209         __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
1210         spin_unlock(&zone->lock);
1211         return i;
1212 }
1213 
1214 #ifdef CONFIG_NUMA
1215 /*
1216  * Called from the vmstat counter updater to drain pagesets of this
1217  * currently executing processor on remote nodes after they have
1218  * expired.
1219  *
1220  * Note that this function must be called with the thread pinned to
1221  * a single processor.
1222  */
1223 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
1224 {
1225         unsigned long flags;
1226         int to_drain;
1227         unsigned long batch;
1228 
1229         local_irq_save(flags);
1230         batch = ACCESS_ONCE(pcp->batch);
1231         if (pcp->count >= batch)
1232                 to_drain = batch;
1233         else
1234                 to_drain = pcp->count;
1235         if (to_drain > 0) {
1236                 free_pcppages_bulk(zone, to_drain, pcp);
1237                 pcp->count -= to_drain;
1238         }
1239         local_irq_restore(flags);
1240 }
1241 static bool gfp_thisnode_allocation(gfp_t gfp_mask)
1242 {
1243         return (gfp_mask & GFP_THISNODE) == GFP_THISNODE;
1244 }
1245 #else
1246 static bool gfp_thisnode_allocation(gfp_t gfp_mask)
1247 {
1248         return false;
1249 }
1250 #endif
1251 
1252 /*
1253  * Drain pages of the indicated processor.
1254  *
1255  * The processor must either be the current processor and the
1256  * thread pinned to the current processor or a processor that
1257  * is not online.
1258  */
1259 static void drain_pages(unsigned int cpu)
1260 {
1261         unsigned long flags;
1262         struct zone *zone;
1263 
1264         for_each_populated_zone(zone) {
1265                 struct per_cpu_pageset *pset;
1266                 struct per_cpu_pages *pcp;
1267 
1268                 local_irq_save(flags);
1269                 pset = per_cpu_ptr(zone->pageset, cpu);
1270 
1271                 pcp = &pset->pcp;
1272                 if (pcp->count) {
1273                         free_pcppages_bulk(zone, pcp->count, pcp);
1274                         pcp->count = 0;
1275                 }
1276                 local_irq_restore(flags);
1277         }
1278 }
1279 
1280 /*
1281  * Spill all of this CPU's per-cpu pages back into the buddy allocator.
1282  */
1283 void drain_local_pages(void *arg)
1284 {
1285         drain_pages(smp_processor_id());
1286 }
1287 
1288 /*
1289  * Spill all the per-cpu pages from all CPUs back into the buddy allocator.
1290  *
1291  * Note that this code is protected against sending an IPI to an offline
1292  * CPU but does not guarantee sending an IPI to newly hotplugged CPUs:
1293  * on_each_cpu_mask() blocks hotplug and won't talk to offlined CPUs but
1294  * nothing keeps CPUs from showing up after we populated the cpumask and
1295  * before the call to on_each_cpu_mask().
1296  */
1297 void drain_all_pages(void)
1298 {
1299         int cpu;
1300         struct per_cpu_pageset *pcp;
1301         struct zone *zone;
1302 
1303         /*
1304          * Allocate in the BSS so we wont require allocation in
1305          * direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
1306          */
1307         static cpumask_t cpus_with_pcps;
1308 
1309         /*
1310          * We don't care about racing with CPU hotplug event
1311          * as offline notification will cause the notified
1312          * cpu to drain that CPU pcps and on_each_cpu_mask
1313          * disables preemption as part of its processing
1314          */
1315         for_each_online_cpu(cpu) {
1316                 bool has_pcps = false;
1317                 for_each_populated_zone(zone) {
1318                         pcp = per_cpu_ptr(zone->pageset, cpu);
1319                         if (pcp->pcp.count) {
1320                                 has_pcps = true;
1321                                 break;
1322                         }
1323                 }
1324                 if (has_pcps)
1325                         cpumask_set_cpu(cpu, &cpus_with_pcps);
1326                 else
1327                         cpumask_clear_cpu(cpu, &cpus_with_pcps);
1328         }
1329         on_each_cpu_mask(&cpus_with_pcps, drain_local_pages, NULL, 1);
1330 }
1331 
1332 #ifdef CONFIG_HIBERNATION
1333 
1334 void mark_free_pages(struct zone *zone)
1335 {
1336         unsigned long pfn, max_zone_pfn;
1337         unsigned long flags;
1338         int order, t;
1339         struct list_head *curr;
1340 
1341         if (zone_is_empty(zone))
1342                 return;
1343 
1344         spin_lock_irqsave(&zone->lock, flags);
1345 
1346         max_zone_pfn = zone_end_pfn(zone);
1347         for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1348                 if (pfn_valid(pfn)) {
1349                         struct page *page = pfn_to_page(pfn);
1350 
1351                         if (!swsusp_page_is_forbidden(page))
1352                                 swsusp_unset_page_free(page);
1353                 }
1354 
1355         for_each_migratetype_order(order, t) {
1356                 list_for_each(curr, &zone->free_area[order].free_list[t]) {
1357                         unsigned long i;
1358 
1359                         pfn = page_to_pfn(list_entry(curr, struct page, lru));
1360                         for (i = 0; i < (1UL << order); i++)
1361                                 swsusp_set_page_free(pfn_to_page(pfn + i));
1362                 }
1363         }
1364         spin_unlock_irqrestore(&zone->lock, flags);
1365 }
1366 #endif /* CONFIG_PM */
1367 
1368 /*
1369  * Free a 0-order page
1370  * cold == 1 ? free a cold page : free a hot page
1371  */
1372 void free_hot_cold_page(struct page *page, int cold)
1373 {
1374         struct zone *zone = page_zone(page);
1375         struct per_cpu_pages *pcp;
1376         unsigned long flags;
1377         int migratetype;
1378 
1379         if (!free_pages_prepare(page, 0))
1380                 return;
1381 
1382         migratetype = get_pageblock_migratetype(page);
1383         set_freepage_migratetype(page, migratetype);
1384         local_irq_save(flags);
1385         __count_vm_event(PGFREE);
1386 
1387         /*
1388          * We only track unmovable, reclaimable and movable on pcp lists.
1389          * Free ISOLATE pages back to the allocator because they are being
1390          * offlined but treat RESERVE as movable pages so we can get those
1391          * areas back if necessary. Otherwise, we may have to free
1392          * excessively into the page allocator
1393          */
1394         if (migratetype >= MIGRATE_PCPTYPES) {
1395                 if (unlikely(is_migrate_isolate(migratetype))) {
1396                         free_one_page(zone, page, 0, migratetype);
1397                         goto out;
1398                 }
1399                 migratetype = MIGRATE_MOVABLE;
1400         }
1401 
1402         pcp = &this_cpu_ptr(zone->pageset)->pcp;
1403         if (cold)
1404                 list_add_tail(&page->lru, &pcp->lists[migratetype]);
1405         else
1406                 list_add(&page->lru, &pcp->lists[migratetype]);
1407         pcp->count++;
1408         if (pcp->count >= pcp->high) {
1409                 unsigned long batch = ACCESS_ONCE(pcp->batch);
1410                 free_pcppages_bulk(zone, batch, pcp);
1411                 pcp->count -= batch;
1412         }
1413 
1414 out:
1415         local_irq_restore(flags);
1416 }
1417 
1418 /*
1419  * Free a list of 0-order pages
1420  */
1421 void free_hot_cold_page_list(struct list_head *list, int cold)
1422 {
1423         struct page *page, *next;
1424 
1425         list_for_each_entry_safe(page, next, list, lru) {
1426                 trace_mm_page_free_batched(page, cold);
1427                 free_hot_cold_page(page, cold);
1428         }
1429 }
1430 
1431 /*
1432  * split_page takes a non-compound higher-order page, and splits it into
1433  * n (1<<order) sub-pages: page[0..n]
1434  * Each sub-page must be freed individually.
1435  *
1436  * Note: this is probably too low level an operation for use in drivers.
1437  * Please consult with lkml before using this in your driver.
1438  */
1439 void split_page(struct page *page, unsigned int order)
1440 {
1441         int i;
1442 
1443         VM_BUG_ON_PAGE(PageCompound(page), page);
1444         VM_BUG_ON_PAGE(!page_count(page), page);
1445 
1446 #ifdef CONFIG_KMEMCHECK
1447         /*
1448          * Split shadow pages too, because free(page[0]) would
1449          * otherwise free the whole shadow.
1450          */
1451         if (kmemcheck_page_is_tracked(page))
1452                 split_page(virt_to_page(page[0].shadow), order);
1453 #endif
1454 
1455         for (i = 1; i < (1 << order); i++)
1456                 set_page_refcounted(page + i);
1457 }
1458 EXPORT_SYMBOL_GPL(split_page);
1459 
1460 static int __isolate_free_page(struct page *page, unsigned int order)
1461 {
1462         unsigned long watermark;
1463         struct zone *zone;
1464         int mt;
1465 
1466         BUG_ON(!PageBuddy(page));
1467 
1468         zone = page_zone(page);
1469         mt = get_pageblock_migratetype(page);
1470 
1471         if (!is_migrate_isolate(mt)) {
1472                 /* Obey watermarks as if the page was being allocated */
1473                 watermark = low_wmark_pages(zone) + (1 << order);
1474                 if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
1475                         return 0;
1476 
1477                 __mod_zone_freepage_state(zone, -(1UL << order), mt);
1478         }
1479 
1480         /* Remove page from free list */
1481         list_del(&page->lru);
1482         zone->free_area[order].nr_free--;
1483         rmv_page_order(page);
1484 
1485         /* Set the pageblock if the isolated page is at least a pageblock */
1486         if (order >= pageblock_order - 1) {
1487                 struct page *endpage = page + (1 << order) - 1;
1488                 for (; page < endpage; page += pageblock_nr_pages) {
1489                         int mt = get_pageblock_migratetype(page);
1490                         if (!is_migrate_isolate(mt) && !is_migrate_cma(mt))
1491                                 set_pageblock_migratetype(page,
1492                                                           MIGRATE_MOVABLE);
1493                 }
1494         }
1495 
1496         return 1UL << order;
1497 }
1498 
1499 /*
1500  * Similar to split_page except the page is already free. As this is only
1501  * being used for migration, the migratetype of the block also changes.
1502  * As this is called with interrupts disabled, the caller is responsible
1503  * for calling arch_alloc_page() and kernel_map_page() after interrupts
1504  * are enabled.
1505  *
1506  * Note: this is probably too low level an operation for use in drivers.
1507  * Please consult with lkml before using this in your driver.
1508  */
1509 int split_free_page(struct page *page)
1510 {
1511         unsigned int order;
1512         int nr_pages;
1513 
1514         order = page_order(page);
1515 
1516         nr_pages = __isolate_free_page(page, order);
1517         if (!nr_pages)
1518                 return 0;
1519 
1520         /* Split into individual pages */
1521         set_page_refcounted(page);
1522         split_page(page, order);
1523         return nr_pages;
1524 }
1525 
1526 /*
1527  * Really, prep_compound_page() should be called from __rmqueue_bulk().  But
1528  * we cheat by calling it from here, in the order > 0 path.  Saves a branch
1529  * or two.
1530  */
1531 static inline
1532 struct page *buffered_rmqueue(struct zone *preferred_zone,
1533                         struct zone *zone, int order, gfp_t gfp_flags,
1534                         int migratetype)
1535 {
1536         unsigned long flags;
1537         struct page *page;
1538         int cold = !!(gfp_flags & __GFP_COLD);
1539 
1540 again:
1541         if (likely(order == 0)) {
1542                 struct per_cpu_pages *pcp;
1543                 struct list_head *list;
1544 
1545                 local_irq_save(flags);
1546                 pcp = &this_cpu_ptr(zone->pageset)->pcp;
1547                 list = &pcp->lists[migratetype];
1548                 if (list_empty(list)) {
1549                         pcp->count += rmqueue_bulk(zone, 0,
1550                                         pcp->batch, list,
1551                                         migratetype, cold);
1552                         if (unlikely(list_empty(list)))
1553                                 goto failed;
1554                 }
1555 
1556                 if (cold)
1557                         page = list_entry(list->prev, struct page, lru);
1558                 else
1559                         page = list_entry(list->next, struct page, lru);
1560 
1561                 list_del(&page->lru);
1562                 pcp->count--;
1563         } else {
1564                 if (unlikely(gfp_flags & __GFP_NOFAIL)) {
1565                         /*
1566                          * __GFP_NOFAIL is not to be used in new code.
1567                          *
1568                          * All __GFP_NOFAIL callers should be fixed so that they
1569                          * properly detect and handle allocation failures.
1570                          *
1571                          * We most definitely don't want callers attempting to
1572                          * allocate greater than order-1 page units with
1573                          * __GFP_NOFAIL.
1574                          */
1575                         WARN_ON_ONCE(order > 1);
1576                 }
1577                 spin_lock_irqsave(&zone->lock, flags);
1578                 page = __rmqueue(zone, order, migratetype);
1579                 spin_unlock(&zone->lock);
1580                 if (!page)
1581                         goto failed;
1582                 __mod_zone_freepage_state(zone, -(1 << order),
1583                                           get_pageblock_migratetype(page));
1584         }
1585 
1586         /*
1587          * NOTE: GFP_THISNODE allocations do not partake in the kswapd
1588          * aging protocol, so they can't be fair.
1589          */
1590         if (!gfp_thisnode_allocation(gfp_flags))
1591                 __mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
1592 
1593         __count_zone_vm_events(PGALLOC, zone, 1 << order);
1594         zone_statistics(preferred_zone, zone, gfp_flags);
1595         local_irq_restore(flags);
1596 
1597         VM_BUG_ON_PAGE(bad_range(zone, page), page);
1598         if (prep_new_page(page, order, gfp_flags))
1599                 goto again;
1600         return page;
1601 
1602 failed:
1603         local_irq_restore(flags);
1604         return NULL;
1605 }
1606 
1607 #ifdef CONFIG_FAIL_PAGE_ALLOC
1608 
1609 static struct {
1610         struct fault_attr attr;
1611 
1612         u32 ignore_gfp_highmem;
1613         u32 ignore_gfp_wait;
1614         u32 min_order;
1615 } fail_page_alloc = {
1616         .attr = FAULT_ATTR_INITIALIZER,
1617         .ignore_gfp_wait = 1,
1618         .ignore_gfp_highmem = 1,
1619         .min_order = 1,
1620 };
1621 
1622 static int __init setup_fail_page_alloc(char *str)
1623 {
1624         return setup_fault_attr(&fail_page_alloc.attr, str);
1625 }
1626 __setup("fail_page_alloc=", setup_fail_page_alloc);
1627 
1628 static bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1629 {
1630         if (order < fail_page_alloc.min_order)
1631                 return false;
1632         if (gfp_mask & __GFP_NOFAIL)
1633                 return false;
1634         if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1635                 return false;
1636         if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1637                 return false;
1638 
1639         return should_fail(&fail_page_alloc.attr, 1 << order);
1640 }
1641 
1642 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1643 
1644 static int __init fail_page_alloc_debugfs(void)
1645 {
1646         umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1647         struct dentry *dir;
1648 
1649         dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
1650                                         &fail_page_alloc.attr);
1651         if (IS_ERR(dir))
1652                 return PTR_ERR(dir);
1653 
1654         if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
1655                                 &fail_page_alloc.ignore_gfp_wait))
1656                 goto fail;
1657         if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1658                                 &fail_page_alloc.ignore_gfp_highmem))
1659                 goto fail;
1660         if (!debugfs_create_u32("min-order", mode, dir,
1661                                 &fail_page_alloc.min_order))
1662                 goto fail;
1663 
1664         return 0;
1665 fail:
1666         debugfs_remove_recursive(dir);
1667 
1668         return -ENOMEM;
1669 }
1670 
1671 late_initcall(fail_page_alloc_debugfs);
1672 
1673 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1674 
1675 #else /* CONFIG_FAIL_PAGE_ALLOC */
1676 
1677 static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1678 {
1679         return false;
1680 }
1681 
1682 #endif /* CONFIG_FAIL_PAGE_ALLOC */
1683 
1684 /*
1685  * Return true if free pages are above 'mark'. This takes into account the order
1686  * of the allocation.
1687  */
1688 static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1689                       int classzone_idx, int alloc_flags, long free_pages)
1690 {
1691         /* free_pages my go negative - that's OK */
1692         long min = mark;
1693         long lowmem_reserve = z->lowmem_reserve[classzone_idx];
1694         int o;
1695         long free_cma = 0;
1696 
1697         free_pages -= (1 << order) - 1;
1698         if (alloc_flags & ALLOC_HIGH)
1699                 min -= min / 2;
1700         if (alloc_flags & ALLOC_HARDER)
1701                 min -= min / 4;
1702 #ifdef CONFIG_CMA
1703         /* If allocation can't use CMA areas don't use free CMA pages */
1704         if (!(alloc_flags & ALLOC_CMA))
1705                 free_cma = zone_page_state(z, NR_FREE_CMA_PAGES);
1706 #endif
1707 
1708         if (free_pages - free_cma <= min + lowmem_reserve)
1709                 return false;
1710         for (o = 0; o < order; o++) {
1711                 /* At the next order, this order's pages become unavailable */
1712                 free_pages -= z->free_area[o].nr_free << o;
1713 
1714                 /* Require fewer higher order pages to be free */
1715                 min >>= 1;
1716 
1717                 if (free_pages <= min)
1718                         return false;
1719         }
1720         return true;
1721 }
1722 
1723 bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1724                       int classzone_idx, int alloc_flags)
1725 {
1726         return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1727                                         zone_page_state(z, NR_FREE_PAGES));
1728 }
1729 
1730 bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark,
1731                       int classzone_idx, int alloc_flags)
1732 {
1733         long free_pages = zone_page_state(z, NR_FREE_PAGES);
1734 
1735         if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
1736                 free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
1737 
1738         return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1739                                                                 free_pages);
1740 }
1741 
1742 #ifdef CONFIG_NUMA
1743 /*
1744  * zlc_setup - Setup for "zonelist cache".  Uses cached zone data to
1745  * skip over zones that are not allowed by the cpuset, or that have
1746  * been recently (in last second) found to be nearly full.  See further
1747  * comments in mmzone.h.  Reduces cache footprint of zonelist scans
1748  * that have to skip over a lot of full or unallowed zones.
1749  *
1750  * If the zonelist cache is present in the passed zonelist, then
1751  * returns a pointer to the allowed node mask (either the current
1752  * tasks mems_allowed, or node_states[N_MEMORY].)
1753  *
1754  * If the zonelist cache is not available for this zonelist, does
1755  * nothing and returns NULL.
1756  *
1757  * If the fullzones BITMAP in the zonelist cache is stale (more than
1758  * a second since last zap'd) then we zap it out (clear its bits.)
1759  *
1760  * We hold off even calling zlc_setup, until after we've checked the
1761  * first zone in the zonelist, on the theory that most allocations will
1762  * be satisfied from that first zone, so best to examine that zone as
1763  * quickly as we can.
1764  */
1765 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1766 {
1767         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1768         nodemask_t *allowednodes;       /* zonelist_cache approximation */
1769 
1770         zlc = zonelist->zlcache_ptr;
1771         if (!zlc)
1772                 return NULL;
1773 
1774         if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1775                 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1776                 zlc->last_full_zap = jiffies;
1777         }
1778 
1779         allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1780                                         &cpuset_current_mems_allowed :
1781                                         &node_states[N_MEMORY];
1782         return allowednodes;
1783 }
1784 
1785 /*
1786  * Given 'z' scanning a zonelist, run a couple of quick checks to see
1787  * if it is worth looking at further for free memory:
1788  *  1) Check that the zone isn't thought to be full (doesn't have its
1789  *     bit set in the zonelist_cache fullzones BITMAP).
1790  *  2) Check that the zones node (obtained from the zonelist_cache
1791  *     z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1792  * Return true (non-zero) if zone is worth looking at further, or
1793  * else return false (zero) if it is not.
1794  *
1795  * This check -ignores- the distinction between various watermarks,
1796  * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ...  If a zone is
1797  * found to be full for any variation of these watermarks, it will
1798  * be considered full for up to one second by all requests, unless
1799  * we are so low on memory on all allowed nodes that we are forced
1800  * into the second scan of the zonelist.
1801  *
1802  * In the second scan we ignore this zonelist cache and exactly
1803  * apply the watermarks to all zones, even it is slower to do so.
1804  * We are low on memory in the second scan, and should leave no stone
1805  * unturned looking for a free page.
1806  */
1807 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1808                                                 nodemask_t *allowednodes)
1809 {
1810         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1811         int i;                          /* index of *z in zonelist zones */
1812         int n;                          /* node that zone *z is on */
1813 
1814         zlc = zonelist->zlcache_ptr;
1815         if (!zlc)
1816                 return 1;
1817 
1818         i = z - zonelist->_zonerefs;
1819         n = zlc->z_to_n[i];
1820 
1821         /* This zone is worth trying if it is allowed but not full */
1822         return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1823 }
1824 
1825 /*
1826  * Given 'z' scanning a zonelist, set the corresponding bit in
1827  * zlc->fullzones, so that subsequent attempts to allocate a page
1828  * from that zone don't waste time re-examining it.
1829  */
1830 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1831 {
1832         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1833         int i;                          /* index of *z in zonelist zones */
1834 
1835         zlc = zonelist->zlcache_ptr;
1836         if (!zlc)
1837                 return;
1838 
1839         i = z - zonelist->_zonerefs;
1840 
1841         set_bit(i, zlc->fullzones);
1842 }
1843 
1844 /*
1845  * clear all zones full, called after direct reclaim makes progress so that
1846  * a zone that was recently full is not skipped over for up to a second
1847  */
1848 static void zlc_clear_zones_full(struct zonelist *zonelist)
1849 {
1850         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1851 
1852         zlc = zonelist->zlcache_ptr;
1853         if (!zlc)
1854                 return;
1855 
1856         bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1857 }
1858 
1859 static bool zone_local(struct zone *local_zone, struct zone *zone)
1860 {
1861         return local_zone->node == zone->node;
1862 }
1863 
1864 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
1865 {
1866         return node_isset(local_zone->node, zone->zone_pgdat->reclaim_nodes);
1867 }
1868 
1869 static void __paginginit init_zone_allows_reclaim(int nid)
1870 {
1871         int i;
1872 
1873         for_each_online_node(i)
1874                 if (node_distance(nid, i) <= RECLAIM_DISTANCE)
1875                         node_set(i, NODE_DATA(nid)->reclaim_nodes);
1876                 else
1877                         zone_reclaim_mode = 1;
1878 }
1879 
1880 #else   /* CONFIG_NUMA */
1881 
1882 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1883 {
1884         return NULL;
1885 }
1886 
1887 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1888                                 nodemask_t *allowednodes)
1889 {
1890         return 1;
1891 }
1892 
1893 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1894 {
1895 }
1896 
1897 static void zlc_clear_zones_full(struct zonelist *zonelist)
1898 {
1899 }
1900 
1901 static bool zone_local(struct zone *local_zone, struct zone *zone)
1902 {
1903         return true;
1904 }
1905 
1906 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
1907 {
1908         return true;
1909 }
1910 
1911 static inline void init_zone_allows_reclaim(int nid)
1912 {
1913 }
1914 #endif  /* CONFIG_NUMA */
1915 
1916 /*
1917  * get_page_from_freelist goes through the zonelist trying to allocate
1918  * a page.
1919  */
1920 static struct page *
1921 get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1922                 struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
1923                 struct zone *preferred_zone, int migratetype)
1924 {
1925         struct zoneref *z;
1926         struct page *page = NULL;
1927         int classzone_idx;
1928         struct zone *zone;
1929         nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1930         int zlc_active = 0;             /* set if using zonelist_cache */
1931         int did_zlc_setup = 0;          /* just call zlc_setup() one time */
1932 
1933         classzone_idx = zone_idx(preferred_zone);
1934 zonelist_scan:
1935         /*
1936          * Scan zonelist, looking for a zone with enough free.
1937          * See also __cpuset_node_allowed_softwall() comment in kernel/cpuset.c.
1938          */
1939         for_each_zone_zonelist_nodemask(zone, z, zonelist,
1940                                                 high_zoneidx, nodemask) {
1941                 unsigned long mark;
1942 
1943                 if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
1944                         !zlc_zone_worth_trying(zonelist, z, allowednodes))
1945                                 continue;
1946                 if ((alloc_flags & ALLOC_CPUSET) &&
1947                         !cpuset_zone_allowed_softwall(zone, gfp_mask))
1948                                 continue;
1949                 BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
1950                 if (unlikely(alloc_flags & ALLOC_NO_WATERMARKS))
1951                         goto try_this_zone;
1952                 /*
1953                  * Distribute pages in proportion to the individual
1954                  * zone size to ensure fair page aging.  The zone a
1955                  * page was allocated in should have no effect on the
1956                  * time the page has in memory before being reclaimed.
1957                  *
1958                  * Try to stay in local zones in the fastpath.  If
1959                  * that fails, the slowpath is entered, which will do
1960                  * another pass starting with the local zones, but
1961                  * ultimately fall back to remote zones that do not
1962                  * partake in the fairness round-robin cycle of this
1963                  * zonelist.
1964                  *
1965                  * NOTE: GFP_THISNODE allocations do not partake in
1966                  * the kswapd aging protocol, so they can't be fair.
1967                  */
1968                 if ((alloc_flags & ALLOC_WMARK_LOW) &&
1969                     !gfp_thisnode_allocation(gfp_mask)) {
1970                         if (zone_page_state(zone, NR_ALLOC_BATCH) <= 0)
1971                                 continue;
1972                         if (!zone_local(preferred_zone, zone))
1973                                 continue;
1974                 }
1975                 /*
1976                  * When allocating a page cache page for writing, we
1977                  * want to get it from a zone that is within its dirty
1978                  * limit, such that no single zone holds more than its
1979                  * proportional share of globally allowed dirty pages.
1980                  * The dirty limits take into account the zone's
1981                  * lowmem reserves and high watermark so that kswapd
1982                  * should be able to balance it without having to
1983                  * write pages from its LRU list.
1984                  *
1985                  * This may look like it could increase pressure on
1986                  * lower zones by failing allocations in higher zones
1987                  * before they are full.  But the pages that do spill
1988                  * over are limited as the lower zones are protected
1989                  * by this very same mechanism.  It should not become
1990                  * a practical burden to them.
1991                  *
1992                  * XXX: For now, allow allocations to potentially
1993                  * exceed the per-zone dirty limit in the slowpath
1994                  * (ALLOC_WMARK_LOW unset) before going into reclaim,
1995                  * which is important when on a NUMA setup the allowed
1996                  * zones are together not big enough to reach the
1997                  * global limit.  The proper fix for these situations
1998                  * will require awareness of zones in the
1999                  * dirty-throttling and the flusher threads.
2000                  */
2001                 if ((alloc_flags & ALLOC_WMARK_LOW) &&
2002                     (gfp_mask & __GFP_WRITE) && !zone_dirty_ok(zone))
2003                         goto this_zone_full;
2004 
2005                 mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
2006                 if (!zone_watermark_ok(zone, order, mark,
2007                                        classzone_idx, alloc_flags)) {
2008                         int ret;
2009 
2010                         if (IS_ENABLED(CONFIG_NUMA) &&
2011                                         !did_zlc_setup && nr_online_nodes > 1) {
2012                                 /*
2013                                  * we do zlc_setup if there are multiple nodes
2014                                  * and before considering the first zone allowed
2015                                  * by the cpuset.
2016                                  */
2017                                 allowednodes = zlc_setup(zonelist, alloc_flags);
2018                                 zlc_active = 1;
2019                                 did_zlc_setup = 1;
2020                         }
2021 
2022                         if (zone_reclaim_mode == 0 ||
2023                             !zone_allows_reclaim(preferred_zone, zone))
2024                                 goto this_zone_full;
2025 
2026                         /*
2027                          * As we may have just activated ZLC, check if the first
2028                          * eligible zone has failed zone_reclaim recently.
2029                          */
2030                         if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
2031                                 !zlc_zone_worth_trying(zonelist, z, allowednodes))
2032                                 continue;
2033 
2034                         ret = zone_reclaim(zone, gfp_mask, order);
2035                         switch (ret) {
2036                         case ZONE_RECLAIM_NOSCAN:
2037                                 /* did not scan */
2038                                 continue;
2039                         case ZONE_RECLAIM_FULL:
2040                                 /* scanned but unreclaimable */
2041                                 continue;
2042                         default:
2043                                 /* did we reclaim enough */
2044                                 if (zone_watermark_ok(zone, order, mark,
2045                                                 classzone_idx, alloc_flags))
2046                                         goto try_this_zone;
2047 
2048                                 /*
2049                                  * Failed to reclaim enough to meet watermark.
2050                                  * Only mark the zone full if checking the min
2051                                  * watermark or if we failed to reclaim just
2052                                  * 1<<order pages or else the page allocator
2053                                  * fastpath will prematurely mark zones full
2054                                  * when the watermark is between the low and
2055                                  * min watermarks.
2056                                  */
2057                                 if (((alloc_flags & ALLOC_WMARK_MASK) == ALLOC_WMARK_MIN) ||
2058                                     ret == ZONE_RECLAIM_SOME)
2059                                         goto this_zone_full;
2060 
2061                                 continue;
2062                         }
2063                 }
2064 
2065 try_this_zone:
2066                 page = buffered_rmqueue(preferred_zone, zone, order,
2067                                                 gfp_mask, migratetype);
2068                 if (page)
2069                         break;
2070 this_zone_full:
2071                 if (IS_ENABLED(CONFIG_NUMA))
2072                         zlc_mark_zone_full(zonelist, z);
2073         }
2074 
2075         if (unlikely(IS_ENABLED(CONFIG_NUMA) && page == NULL && zlc_active)) {
2076                 /* Disable zlc cache for second zonelist scan */
2077                 zlc_active = 0;
2078                 goto zonelist_scan;
2079         }
2080 
2081         if (page)
2082                 /*
2083                  * page->pfmemalloc is set when ALLOC_NO_WATERMARKS was
2084                  * necessary to allocate the page. The expectation is
2085                  * that the caller is taking steps that will free more
2086                  * memory. The caller should avoid the page being used
2087                  * for !PFMEMALLOC purposes.
2088                  */
2089                 page->pfmemalloc = !!(alloc_flags & ALLOC_NO_WATERMARKS);
2090 
2091         return page;
2092 }
2093 
2094 /*
2095  * Large machines with many possible nodes should not always dump per-node
2096  * meminfo in irq context.
2097  */
2098 static inline bool should_suppress_show_mem(void)
2099 {
2100         bool ret = false;
2101 
2102 #if NODES_SHIFT > 8
2103         ret = in_interrupt();
2104 #endif
2105         return ret;
2106 }
2107 
2108 static DEFINE_RATELIMIT_STATE(nopage_rs,
2109                 DEFAULT_RATELIMIT_INTERVAL,
2110                 DEFAULT_RATELIMIT_BURST);
2111 
2112 void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...)
2113 {
2114         unsigned int filter = SHOW_MEM_FILTER_NODES;
2115 
2116         if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) ||
2117             debug_guardpage_minorder() > 0)
2118                 return;
2119 
2120         /*
2121          * This documents exceptions given to allocations in certain
2122          * contexts that are allowed to allocate outside current's set
2123          * of allowed nodes.
2124          */
2125         if (!(gfp_mask & __GFP_NOMEMALLOC))
2126                 if (test_thread_flag(TIF_MEMDIE) ||
2127                     (current->flags & (PF_MEMALLOC | PF_EXITING)))
2128                         filter &= ~SHOW_MEM_FILTER_NODES;
2129         if (in_interrupt() || !(gfp_mask & __GFP_WAIT))
2130                 filter &= ~SHOW_MEM_FILTER_NODES;
2131 
2132         if (fmt) {
2133                 struct va_format vaf;
2134                 va_list args;
2135 
2136                 va_start(args, fmt);
2137 
2138                 vaf.fmt = fmt;
2139                 vaf.va = &args;
2140 
2141                 pr_warn("%pV", &vaf);
2142 
2143                 va_end(args);
2144         }
2145 
2146         pr_warn("%s: page allocation failure: order:%d, mode:0x%x\n",
2147                 current->comm, order, gfp_mask);
2148 
2149         dump_stack();
2150         if (!should_suppress_show_mem())
2151                 show_mem(filter);
2152 }
2153 
2154 static inline int
2155 should_alloc_retry(gfp_t gfp_mask, unsigned int order,
2156                                 unsigned long did_some_progress,
2157                                 unsigned long pages_reclaimed)
2158 {
2159         /* Do not loop if specifically requested */
2160         if (gfp_mask & __GFP_NORETRY)
2161                 return 0;
2162 
2163         /* Always retry if specifically requested */
2164         if (gfp_mask & __GFP_NOFAIL)
2165                 return 1;
2166 
2167         /*
2168          * Suspend converts GFP_KERNEL to __GFP_WAIT which can prevent reclaim
2169          * making forward progress without invoking OOM. Suspend also disables
2170          * storage devices so kswapd will not help. Bail if we are suspending.
2171          */
2172         if (!did_some_progress && pm_suspended_storage())
2173                 return 0;
2174 
2175         /*
2176          * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
2177          * means __GFP_NOFAIL, but that may not be true in other
2178          * implementations.
2179          */
2180         if (order <= PAGE_ALLOC_COSTLY_ORDER)
2181                 return 1;
2182 
2183         /*
2184          * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
2185          * specified, then we retry until we no longer reclaim any pages
2186          * (above), or we've reclaimed an order of pages at least as
2187          * large as the allocation's order. In both cases, if the
2188          * allocation still fails, we stop retrying.
2189          */
2190         if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
2191                 return 1;
2192 
2193         return 0;
2194 }
2195 
2196 static inline struct page *
2197 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
2198         struct zonelist *zonelist, enum zone_type high_zoneidx,
2199         nodemask_t *nodemask, struct zone *preferred_zone,
2200         int migratetype)
2201 {
2202         struct page *page;
2203 
2204         /* Acquire the OOM killer lock for the zones in zonelist */
2205         if (!try_set_zonelist_oom(zonelist, gfp_mask)) {
2206                 schedule_timeout_uninterruptible(1);
2207                 return NULL;
2208         }
2209 
2210         /*
2211          * Go through the zonelist yet one more time, keep very high watermark
2212          * here, this is only to catch a parallel oom killing, we must fail if
2213          * we're still under heavy pressure.
2214          */
2215         page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
2216                 order, zonelist, high_zoneidx,
2217                 ALLOC_WMARK_HIGH|ALLOC_CPUSET,
2218                 preferred_zone, migratetype);
2219         if (page)
2220                 goto out;
2221 
2222         if (!(gfp_mask & __GFP_NOFAIL)) {
2223                 /* The OOM killer will not help higher order allocs */
2224                 if (order > PAGE_ALLOC_COSTLY_ORDER)
2225                         goto out;
2226                 /* The OOM killer does not needlessly kill tasks for lowmem */
2227                 if (high_zoneidx < ZONE_NORMAL)
2228                         goto out;
2229                 /*
2230                  * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
2231                  * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
2232                  * The caller should handle page allocation failure by itself if
2233                  * it specifies __GFP_THISNODE.
2234                  * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
2235                  */
2236                 if (gfp_mask & __GFP_THISNODE)
2237                         goto out;
2238         }
2239         /* Exhausted what can be done so it's blamo time */
2240         out_of_memory(zonelist, gfp_mask, order, nodemask, false);
2241 
2242 out:
2243         clear_zonelist_oom(zonelist, gfp_mask);
2244         return page;
2245 }
2246 
2247 #ifdef CONFIG_COMPACTION
2248 /* Try memory compaction for high-order allocations before reclaim */
2249 static struct page *
2250 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2251         struct zonelist *zonelist, enum zone_type high_zoneidx,
2252         nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2253         int migratetype, bool sync_migration,
2254         bool *contended_compaction, bool *deferred_compaction,
2255         unsigned long *did_some_progress)
2256 {
2257         if (!order)
2258                 return NULL;
2259 
2260         if (compaction_deferred(preferred_zone, order)) {
2261                 *deferred_compaction = true;
2262                 return NULL;
2263         }
2264 
2265         current->flags |= PF_MEMALLOC;
2266         *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
2267                                                 nodemask, sync_migration,
2268                                                 contended_compaction);
2269         current->flags &= ~PF_MEMALLOC;
2270 
2271         if (*did_some_progress != COMPACT_SKIPPED) {
2272                 struct page *page;
2273 
2274                 /* Page migration frees to the PCP lists but we want merging */
2275                 drain_pages(get_cpu());
2276                 put_cpu();
2277 
2278                 page = get_page_from_freelist(gfp_mask, nodemask,
2279                                 order, zonelist, high_zoneidx,
2280                                 alloc_flags & ~ALLOC_NO_WATERMARKS,
2281                                 preferred_zone, migratetype);
2282                 if (page) {
2283                         preferred_zone->compact_blockskip_flush = false;
2284                         compaction_defer_reset(preferred_zone, order, true);
2285                         count_vm_event(COMPACTSUCCESS);
2286                         return page;
2287                 }
2288 
2289                 /*
2290                  * It's bad if compaction run occurs and fails.
2291                  * The most likely reason is that pages exist,
2292                  * but not enough to satisfy watermarks.
2293                  */
2294                 count_vm_event(COMPACTFAIL);
2295 
2296                 /*
2297                  * As async compaction considers a subset of pageblocks, only
2298                  * defer if the failure was a sync compaction failure.
2299                  */
2300                 if (sync_migration)
2301                         defer_compaction(preferred_zone, order);
2302 
2303                 cond_resched();
2304         }
2305 
2306         return NULL;
2307 }
2308 #else
2309 static inline struct page *
2310 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
2311         struct zonelist *zonelist, enum zone_type high_zoneidx,
2312         nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2313         int migratetype, bool sync_migration,
2314         bool *contended_compaction, bool *deferred_compaction,
2315         unsigned long *did_some_progress)
2316 {
2317         return NULL;
2318 }
2319 #endif /* CONFIG_COMPACTION */
2320 
2321 /* Perform direct synchronous page reclaim */
2322 static int
2323 __perform_reclaim(gfp_t gfp_mask, unsigned int order, struct zonelist *zonelist,
2324                   nodemask_t *nodemask)
2325 {
2326         struct reclaim_state reclaim_state;
2327         int progress;
2328 
2329         cond_resched();
2330 
2331         /* We now go into synchronous reclaim */
2332         cpuset_memory_pressure_bump();
2333         current->flags |= PF_MEMALLOC;
2334         lockdep_set_current_reclaim_state(gfp_mask);
2335         reclaim_state.reclaimed_slab = 0;
2336         current->reclaim_state = &reclaim_state;
2337 
2338         progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
2339 
2340         current->reclaim_state = NULL;
2341         lockdep_clear_current_reclaim_state();
2342         current->flags &= ~PF_MEMALLOC;
2343 
2344         cond_resched();
2345 
2346         return progress;
2347 }
2348 
2349 /* The really slow allocator path where we enter direct reclaim */
2350 static inline struct page *
2351 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
2352         struct zonelist *zonelist, enum zone_type high_zoneidx,
2353         nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
2354         int migratetype, unsigned long *did_some_progress)
2355 {
2356         struct page *page = NULL;
2357         bool drained = false;
2358 
2359         *did_some_progress = __perform_reclaim(gfp_mask, order, zonelist,
2360                                                nodemask);
2361         if (unlikely(!(*did_some_progress)))
2362                 return NULL;
2363 
2364         /* After successful reclaim, reconsider all zones for allocation */
2365         if (IS_ENABLED(CONFIG_NUMA))
2366                 zlc_clear_zones_full(zonelist);
2367 
2368 retry:
2369         page = get_page_from_freelist(gfp_mask, nodemask, order,
2370                                         zonelist, high_zoneidx,
2371                                         alloc_flags & ~ALLOC_NO_WATERMARKS,
2372                                         preferred_zone, migratetype);
2373 
2374         /*
2375          * If an allocation failed after direct reclaim, it could be because
2376          * pages are pinned on the per-cpu lists. Drain them and try again
2377          */
2378         if (!page && !drained) {
2379                 drain_all_pages();
2380                 drained = true;
2381                 goto retry;
2382         }
2383 
2384         return page;
2385 }
2386 
2387 /*
2388  * This is called in the allocator slow-path if the allocation request is of
2389  * sufficient urgency to ignore watermarks and take other desperate measures
2390  */
2391 static inline struct page *
2392 __alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
2393         struct zonelist *zonelist, enum zone_type high_zoneidx,
2394         nodemask_t *nodemask, struct zone *preferred_zone,
2395         int migratetype)
2396 {
2397         struct page *page;
2398 
2399         do {
2400                 page = get_page_from_freelist(gfp_mask, nodemask, order,
2401                         zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
2402                         preferred_zone, migratetype);
2403 
2404                 if (!page && gfp_mask & __GFP_NOFAIL)
2405                         wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2406         } while (!page && (gfp_mask & __GFP_NOFAIL));
2407 
2408         return page;
2409 }
2410 
2411 static void prepare_slowpath(gfp_t gfp_mask, unsigned int order,
2412                              struct zonelist *zonelist,
2413                              enum zone_type high_zoneidx,
2414                              struct zone *preferred_zone)
2415 {
2416         struct zoneref *z;
2417         struct zone *zone;
2418 
2419         for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
2420                 if (!(gfp_mask & __GFP_NO_KSWAPD))
2421                         wakeup_kswapd(zone, order, zone_idx(preferred_zone));
2422                 /*
2423                  * Only reset the batches of zones that were actually
2424                  * considered in the fast path, we don't want to
2425                  * thrash fairness information for zones that are not
2426                  * actually part of this zonelist's round-robin cycle.
2427                  */
2428                 if (!zone_local(preferred_zone, zone))
2429                         continue;
2430                 mod_zone_page_state(zone, NR_ALLOC_BATCH,
2431                                     high_wmark_pages(zone) -
2432                                     low_wmark_pages(zone) -
2433                                     zone_page_state(zone, NR_ALLOC_BATCH));
2434         }
2435 }
2436 
2437 static inline int
2438 gfp_to_alloc_flags(gfp_t gfp_mask)
2439 {
2440         int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
2441         const gfp_t wait = gfp_mask & __GFP_WAIT;
2442 
2443         /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
2444         BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
2445 
2446         /*
2447          * The caller may dip into page reserves a bit more if the caller
2448          * cannot run direct reclaim, or if the caller has realtime scheduling
2449          * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
2450          * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
2451          */
2452         alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
2453 
2454         if (!wait) {
2455                 /*
2456                  * Not worth trying to allocate harder for
2457                  * __GFP_NOMEMALLOC even if it can't schedule.
2458                  */
2459                 if  (!(gfp_mask & __GFP_NOMEMALLOC))
2460                         alloc_flags |= ALLOC_HARDER;
2461                 /*
2462                  * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
2463                  * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
2464                  */
2465                 alloc_flags &= ~ALLOC_CPUSET;
2466         } else if (unlikely(rt_task(current)) && !in_interrupt())
2467                 alloc_flags |= ALLOC_HARDER;
2468 
2469         if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
2470                 if (gfp_mask & __GFP_MEMALLOC)
2471                         alloc_flags |= ALLOC_NO_WATERMARKS;
2472                 else if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
2473                         alloc_flags |= ALLOC_NO_WATERMARKS;
2474                 else if (!in_interrupt() &&
2475                                 ((current->flags & PF_MEMALLOC) ||
2476                                  unlikely(test_thread_flag(TIF_MEMDIE))))
2477                         alloc_flags |= ALLOC_NO_WATERMARKS;
2478         }
2479 #ifdef CONFIG_CMA
2480         if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
2481                 alloc_flags |= ALLOC_CMA;
2482 #endif
2483         return alloc_flags;
2484 }
2485 
2486 bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
2487 {
2488         return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_NO_WATERMARKS);
2489 }
2490 
2491 static inline struct page *
2492 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
2493         struct zonelist *zonelist, enum zone_type high_zoneidx,
2494         nodemask_t *nodemask, struct zone *preferred_zone,
2495         int migratetype)
2496 {
2497         const gfp_t wait = gfp_mask & __GFP_WAIT;
2498         struct page *page = NULL;
2499         int alloc_flags;
2500         unsigned long pages_reclaimed = 0;
2501         unsigned long did_some_progress;
2502         bool sync_migration = false;
2503         bool deferred_compaction = false;
2504         bool contended_compaction = false;
2505 
2506         /*
2507          * In the slowpath, we sanity check order to avoid ever trying to
2508          * reclaim >= MAX_ORDER areas which will never succeed. Callers may
2509          * be using allocators in order of preference for an area that is
2510          * too large.
2511          */
2512         if (order >= MAX_ORDER) {
2513                 WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
2514                 return NULL;
2515         }
2516 
2517         /*
2518          * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
2519          * __GFP_NOWARN set) should not cause reclaim since the subsystem
2520          * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
2521          * using a larger set of nodes after it has established that the
2522          * allowed per node queues are empty and that nodes are
2523          * over allocated.
2524          */
2525         if (gfp_thisnode_allocation(gfp_mask))
2526                 goto nopage;
2527 
2528 restart:
2529         prepare_slowpath(gfp_mask, order, zonelist,
2530                          high_zoneidx, preferred_zone);
2531 
2532         /*
2533          * OK, we're below the kswapd watermark and have kicked background
2534          * reclaim. Now things get more complex, so set up alloc_flags according
2535          * to how we want to proceed.
2536          */
2537         alloc_flags = gfp_to_alloc_flags(gfp_mask);
2538 
2539         /*
2540          * Find the true preferred zone if the allocation is unconstrained by
2541          * cpusets.
2542          */
2543         if (!(alloc_flags & ALLOC_CPUSET) && !nodemask)
2544                 first_zones_zonelist(zonelist, high_zoneidx, NULL,
2545                                         &preferred_zone);
2546 
2547 rebalance:
2548         /* This is the last chance, in general, before the goto nopage. */
2549         page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
2550                         high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
2551                         preferred_zone, migratetype);
2552         if (page)
2553                 goto got_pg;
2554 
2555         /* Allocate without watermarks if the context allows */
2556         if (alloc_flags & ALLOC_NO_WATERMARKS) {
2557                 /*
2558                  * Ignore mempolicies if ALLOC_NO_WATERMARKS on the grounds
2559                  * the allocation is high priority and these type of
2560                  * allocations are system rather than user orientated
2561                  */
2562                 zonelist = node_zonelist(numa_node_id(), gfp_mask);
2563 
2564                 page = __alloc_pages_high_priority(gfp_mask, order,
2565                                 zonelist, high_zoneidx, nodemask,
2566                                 preferred_zone, migratetype);
2567                 if (page) {
2568                         goto got_pg;
2569                 }
2570         }
2571 
2572         /* Atomic allocations - we can't balance anything */
2573         if (!wait) {
2574                 /*
2575                  * All existing users of the deprecated __GFP_NOFAIL are
2576                  * blockable, so warn of any new users that actually allow this
2577                  * type of allocation to fail.
2578                  */
2579                 WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL);
2580                 goto nopage;
2581         }
2582 
2583         /* Avoid recursion of direct reclaim */
2584         if (current->flags & PF_MEMALLOC)
2585                 goto nopage;
2586 
2587         /* Avoid allocations with no watermarks from looping endlessly */
2588         if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
2589                 goto nopage;
2590 
2591         /*
2592          * Try direct compaction. The first pass is asynchronous. Subsequent
2593          * attempts after direct reclaim are synchronous
2594          */
2595         page = __alloc_pages_direct_compact(gfp_mask, order,
2596                                         zonelist, high_zoneidx,
2597                                         nodemask,
2598                                         alloc_flags, preferred_zone,
2599                                         migratetype, sync_migration,
2600                                         &contended_compaction,
2601                                         &deferred_compaction,
2602                                         &did_some_progress);
2603         if (page)
2604                 goto got_pg;
2605         sync_migration = true;
2606 
2607         /*
2608          * If compaction is deferred for high-order allocations, it is because
2609          * sync compaction recently failed. In this is the case and the caller
2610          * requested a movable allocation that does not heavily disrupt the
2611          * system then fail the allocation instead of entering direct reclaim.
2612          */
2613         if ((deferred_compaction || contended_compaction) &&
2614                                                 (gfp_mask & __GFP_NO_KSWAPD))
2615                 goto nopage;
2616 
2617         /* Try direct reclaim and then allocating */
2618         page = __alloc_pages_direct_reclaim(gfp_mask, order,
2619                                         zonelist, high_zoneidx,
2620                                         nodemask,
2621                                         alloc_flags, preferred_zone,
2622                                         migratetype, &did_some_progress);
2623         if (page)
2624                 goto got_pg;
2625 
2626         /*
2627          * If we failed to make any progress reclaiming, then we are
2628          * running out of options and have to consider going OOM
2629          */
2630         if (!did_some_progress) {
2631                 if (oom_gfp_allowed(gfp_mask)) {
2632                         if (oom_killer_disabled)
2633                                 goto nopage;
2634                         /* Coredumps can quickly deplete all memory reserves */
2635                         if ((current->flags & PF_DUMPCORE) &&
2636                             !(gfp_mask & __GFP_NOFAIL))
2637                                 goto nopage;
2638                         page = __alloc_pages_may_oom(gfp_mask, order,
2639                                         zonelist, high_zoneidx,
2640                                         nodemask, preferred_zone,
2641                                         migratetype);
2642                         if (page)
2643                                 goto got_pg;
2644 
2645                         if (!(gfp_mask & __GFP_NOFAIL)) {
2646                                 /*
2647                                  * The oom killer is not called for high-order
2648                                  * allocations that may fail, so if no progress
2649                                  * is being made, there are no other options and
2650                                  * retrying is unlikely to help.
2651                                  */
2652                                 if (order > PAGE_ALLOC_COSTLY_ORDER)
2653                                         goto nopage;
2654                                 /*
2655                                  * The oom killer is not called for lowmem
2656                                  * allocations to prevent needlessly killing
2657                                  * innocent tasks.
2658                                  */
2659                                 if (high_zoneidx < ZONE_NORMAL)
2660                                         goto nopage;
2661                         }
2662 
2663                         goto restart;
2664                 }
2665         }
2666 
2667         /* Check if we should retry the allocation */
2668         pages_reclaimed += did_some_progress;
2669         if (should_alloc_retry(gfp_mask, order, did_some_progress,
2670                                                 pages_reclaimed)) {
2671                 /* Wait for some write requests to complete then retry */
2672                 wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2673                 goto rebalance;
2674         } else {
2675                 /*
2676                  * High-order allocations do not necessarily loop after
2677                  * direct reclaim and reclaim/compaction depends on compaction
2678                  * being called after reclaim so call directly if necessary
2679                  */
2680                 page = __alloc_pages_direct_compact(gfp_mask, order,
2681                                         zonelist, high_zoneidx,
2682                                         nodemask,
2683                                         alloc_flags, preferred_zone,
2684                                         migratetype, sync_migration,
2685                                         &contended_compaction,
2686                                         &deferred_compaction,
2687                                         &did_some_progress);
2688                 if (page)
2689                         goto got_pg;
2690         }
2691 
2692 nopage:
2693         warn_alloc_failed(gfp_mask, order, NULL);
2694         return page;
2695 got_pg:
2696         if (kmemcheck_enabled)
2697                 kmemcheck_pagealloc_alloc(page, order, gfp_mask);
2698 
2699         return page;
2700 }
2701 
2702 /*
2703  * This is the 'heart' of the zoned buddy allocator.
2704  */
2705 struct page *
2706 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
2707                         struct zonelist *zonelist, nodemask_t *nodemask)
2708 {
2709         enum zone_type high_zoneidx = gfp_zone(gfp_mask);
2710         struct zone *preferred_zone;
2711         struct page *page = NULL;
2712         int migratetype = allocflags_to_migratetype(gfp_mask);
2713         unsigned int cpuset_mems_cookie;
2714         int alloc_flags = ALLOC_WMARK_LOW|ALLOC_CPUSET;
2715         struct mem_cgroup *memcg = NULL;
2716 
2717         gfp_mask &= gfp_allowed_mask;
2718 
2719         lockdep_trace_alloc(gfp_mask);
2720 
2721         might_sleep_if(gfp_mask & __GFP_WAIT);
2722 
2723         if (should_fail_alloc_page(gfp_mask, order))
2724                 return NULL;
2725 
2726         /*
2727          * Check the zones suitable for the gfp_mask contain at least one
2728          * valid zone. It's possible to have an empty zonelist as a result
2729          * of GFP_THISNODE and a memoryless node
2730          */
2731         if (unlikely(!zonelist->_zonerefs->zone))
2732                 return NULL;
2733 
2734         /*
2735          * Will only have any effect when __GFP_KMEMCG is set.  This is
2736          * verified in the (always inline) callee
2737          */
2738         if (!memcg_kmem_newpage_charge(gfp_mask, &memcg, order))
2739                 return NULL;
2740 
2741 retry_cpuset:
2742         cpuset_mems_cookie = get_mems_allowed();
2743 
2744         /* The preferred zone is used for statistics later */
2745         first_zones_zonelist(zonelist, high_zoneidx,
2746                                 nodemask ? : &cpuset_current_mems_allowed,
2747                                 &preferred_zone);
2748         if (!preferred_zone)
2749                 goto out;
2750 
2751 #ifdef CONFIG_CMA
2752         if (allocflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
2753                 alloc_flags |= ALLOC_CMA;
2754 #endif
2755         /* First allocation attempt */
2756         page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
2757                         zonelist, high_zoneidx, alloc_flags,
2758                         preferred_zone, migratetype);
2759         if (unlikely(!page)) {
2760                 /*
2761                  * Runtime PM, block IO and its error handling path
2762                  * can deadlock because I/O on the device might not
2763                  * complete.
2764                  */
2765                 gfp_mask = memalloc_noio_flags(gfp_mask);
2766                 page = __alloc_pages_slowpath(gfp_mask, order,
2767                                 zonelist, high_zoneidx, nodemask,
2768                                 preferred_zone, migratetype);
2769         }
2770 
2771         trace_mm_page_alloc(page, order, gfp_mask, migratetype);
2772 
2773 out:
2774         /*
2775          * When updating a task's mems_allowed, it is possible to race with
2776          * parallel threads in such a way that an allocation can fail while
2777          * the mask is being updated. If a page allocation is about to fail,
2778          * check if the cpuset changed during allocation and if so, retry.
2779          */
2780         if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
2781                 goto retry_cpuset;
2782 
2783         memcg_kmem_commit_charge(page, memcg, order);
2784 
2785         return page;
2786 }
2787 EXPORT_SYMBOL(__alloc_pages_nodemask);
2788 
2789 /*
2790  * Common helper functions.
2791  */
2792 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
2793 {
2794         struct page *page;
2795 
2796         /*
2797          * __get_free_pages() returns a 32-bit address, which cannot represent
2798          * a highmem page
2799          */
2800         VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
2801 
2802         page = alloc_pages(gfp_mask, order);
2803         if (!page)
2804                 return 0;
2805         return (unsigned long) page_address(page);
2806 }
2807 EXPORT_SYMBOL(__get_free_pages);
2808 
2809 unsigned long get_zeroed_page(gfp_t gfp_mask)
2810 {
2811         return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
2812 }
2813 EXPORT_SYMBOL(get_zeroed_page);
2814 
2815 void __free_pages(struct page *page, unsigned int order)
2816 {
2817         if (put_page_testzero(page)) {
2818                 if (order == 0)
2819                         free_hot_cold_page(page, 0);
2820                 else
2821                         __free_pages_ok(page, order);
2822         }
2823 }
2824 
2825 EXPORT_SYMBOL(__free_pages);
2826 
2827 void free_pages(unsigned long addr, unsigned int order)
2828 {
2829         if (addr != 0) {
2830                 VM_BUG_ON(!virt_addr_valid((void *)addr));
2831                 __free_pages(virt_to_page((void *)addr), order);
2832         }
2833 }
2834 
2835 EXPORT_SYMBOL(free_pages);
2836 
2837 /*
2838  * __free_memcg_kmem_pages and free_memcg_kmem_pages will free
2839  * pages allocated with __GFP_KMEMCG.
2840  *
2841  * Those pages are accounted to a particular memcg, embedded in the
2842  * corresponding page_cgroup. To avoid adding a hit in the allocator to search
2843  * for that information only to find out that it is NULL for users who have no
2844  * interest in that whatsoever, we provide these functions.
2845  *
2846  * The caller knows better which flags it relies on.
2847  */
2848 void __free_memcg_kmem_pages(struct page *page, unsigned int order)
2849 {
2850         memcg_kmem_uncharge_pages(page, order);
2851         __free_pages(page, order);
2852 }
2853 
2854 void free_memcg_kmem_pages(unsigned long addr, unsigned int order)
2855 {
2856         if (addr != 0) {
2857                 VM_BUG_ON(!virt_addr_valid((void *)addr));
2858                 __free_memcg_kmem_pages(virt_to_page((void *)addr), order);
2859         }
2860 }
2861 
2862 static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
2863 {
2864         if (addr) {
2865                 unsigned long alloc_end = addr + (PAGE_SIZE << order);
2866                 unsigned long used = addr + PAGE_ALIGN(size);
2867 
2868                 split_page(virt_to_page((void *)addr), order);
2869                 while (used < alloc_end) {
2870                         free_page(used);
2871                         used += PAGE_SIZE;
2872                 }
2873         }
2874         return (void *)addr;
2875 }
2876 
2877 /**
2878  * alloc_pages_exact - allocate an exact number physically-contiguous pages.
2879  * @size: the number of bytes to allocate
2880  * @gfp_mask: GFP flags for the allocation
2881  *
2882  * This function is similar to alloc_pages(), except that it allocates the
2883  * minimum number of pages to satisfy the request.  alloc_pages() can only
2884  * allocate memory in power-of-two pages.
2885  *
2886  * This function is also limited by MAX_ORDER.
2887  *
2888  * Memory allocated by this function must be released by free_pages_exact().
2889  */
2890 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
2891 {
2892         unsigned int order = get_order(size);
2893         unsigned long addr;
2894 
2895         addr = __get_free_pages(gfp_mask, order);
2896         return make_alloc_exact(addr, order, size);
2897 }
2898 EXPORT_SYMBOL(alloc_pages_exact);
2899 
2900 /**
2901  * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
2902  *                         pages on a node.
2903  * @nid: the preferred node ID where memory should be allocated
2904  * @size: the number of bytes to allocate
2905  * @gfp_mask: GFP flags for the allocation
2906  *
2907  * Like alloc_pages_exact(), but try to allocate on node nid first before falling
2908  * back.
2909  * Note this is not alloc_pages_exact_node() which allocates on a specific node,
2910  * but is not exact.
2911  */
2912 void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
2913 {
2914         unsigned order = get_order(size);
2915         struct page *p = alloc_pages_node(nid, gfp_mask, order);
2916         if (!p)
2917                 return NULL;
2918         return make_alloc_exact((unsigned long)page_address(p), order, size);
2919 }
2920 EXPORT_SYMBOL(alloc_pages_exact_nid);
2921 
2922 /**
2923  * free_pages_exact - release memory allocated via alloc_pages_exact()
2924  * @virt: the value returned by alloc_pages_exact.
2925  * @size: size of allocation, same value as passed to alloc_pages_exact().
2926  *
2927  * Release the memory allocated by a previous call to alloc_pages_exact.
2928  */
2929 void free_pages_exact(void *virt, size_t size)
2930 {
2931         unsigned long addr = (unsigned long)virt;
2932         unsigned long end = addr + PAGE_ALIGN(size);
2933 
2934         while (addr < end) {
2935                 free_page(addr);
2936                 addr += PAGE_SIZE;
2937         }
2938 }
2939 EXPORT_SYMBOL(free_pages_exact);
2940 
2941 /**
2942  * nr_free_zone_pages - count number of pages beyond high watermark
2943  * @offset: The zone index of the highest zone
2944  *
2945  * nr_free_zone_pages() counts the number of counts pages which are beyond the
2946  * high watermark within all zones at or below a given zone index.  For each
2947  * zone, the number of pages is calculated as:
2948  *     managed_pages - high_pages
2949  */
2950 static unsigned long nr_free_zone_pages(int offset)
2951 {
2952         struct zoneref *z;
2953         struct zone *zone;
2954 
2955         /* Just pick one node, since fallback list is circular */
2956         unsigned long sum = 0;
2957 
2958         struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
2959 
2960         for_each_zone_zonelist(zone, z, zonelist, offset) {
2961                 unsigned long size = zone->managed_pages;
2962                 unsigned long high = high_wmark_pages(zone);
2963                 if (size > high)
2964                         sum += size - high;
2965         }
2966 
2967         return sum;
2968 }
2969 
2970 /**
2971  * nr_free_buffer_pages - count number of pages beyond high watermark
2972  *
2973  * nr_free_buffer_pages() counts the number of pages which are beyond the high
2974  * watermark within ZONE_DMA and ZONE_NORMAL.
2975  */
2976 unsigned long nr_free_buffer_pages(void)
2977 {
2978         return nr_free_zone_pages(gfp_zone(GFP_USER));
2979 }
2980 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
2981 
2982 /**
2983  * nr_free_pagecache_pages - count number of pages beyond high watermark
2984  *
2985  * nr_free_pagecache_pages() counts the number of pages which are beyond the
2986  * high watermark within all zones.
2987  */
2988 unsigned long nr_free_pagecache_pages(void)
2989 {
2990         return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
2991 }
2992 
2993 static inline void show_node(struct zone *zone)
2994 {
2995         if (IS_ENABLED(CONFIG_NUMA))
2996                 printk("Node %d ", zone_to_nid(zone));
2997 }
2998 
2999 void si_meminfo(struct sysinfo *val)
3000 {
3001         val->totalram = totalram_pages;
3002         val->sharedram = 0;
3003         val->freeram = global_page_state(NR_FREE_PAGES);
3004         val->bufferram = nr_blockdev_pages();
3005         val->totalhigh = totalhigh_pages;
3006         val->freehigh = nr_free_highpages();
3007         val->mem_unit = PAGE_SIZE;
3008 }
3009 
3010 EXPORT_SYMBOL(si_meminfo);
3011 
3012 #ifdef CONFIG_NUMA
3013 void si_meminfo_node(struct sysinfo *val, int nid)
3014 {
3015         int zone_type;          /* needs to be signed */
3016         unsigned long managed_pages = 0;
3017         pg_data_t *pgdat = NODE_DATA(nid);
3018 
3019         for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
3020                 managed_pages += pgdat->node_zones[zone_type].managed_pages;
3021         val->totalram = managed_pages;
3022         val->freeram = node_page_state(nid, NR_FREE_PAGES);
3023 #ifdef CONFIG_HIGHMEM
3024         val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].managed_pages;
3025         val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
3026                         NR_FREE_PAGES);
3027 #else
3028         val->totalhigh = 0;
3029         val->freehigh = 0;
3030 #endif
3031         val->mem_unit = PAGE_SIZE;
3032 }
3033 #endif
3034 
3035 /*
3036  * Determine whether the node should be displayed or not, depending on whether
3037  * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
3038  */
3039 bool skip_free_areas_node(unsigned int flags, int nid)
3040 {
3041         bool ret = false;
3042         unsigned int cpuset_mems_cookie;
3043 
3044         if (!(flags & SHOW_MEM_FILTER_NODES))
3045                 goto out;
3046 
3047         do {
3048                 cpuset_mems_cookie = get_mems_allowed();
3049                 ret = !node_isset(nid, cpuset_current_mems_allowed);
3050         } while (!put_mems_allowed(cpuset_mems_cookie));
3051 out:
3052         return ret;
3053 }
3054 
3055 #define K(x) ((x) << (PAGE_SHIFT-10))
3056 
3057 static void show_migration_types(unsigned char type)
3058 {
3059         static const char types[MIGRATE_TYPES] = {
3060                 [MIGRATE_UNMOVABLE]     = 'U',
3061                 [MIGRATE_RECLAIMABLE]   = 'E',
3062                 [MIGRATE_MOVABLE]       = 'M',
3063                 [MIGRATE_RESERVE]       = 'R',
3064 #ifdef CONFIG_CMA
3065                 [MIGRATE_CMA]           = 'C',
3066 #endif
3067 #ifdef CONFIG_MEMORY_ISOLATION
3068                 [MIGRATE_ISOLATE]       = 'I',
3069 #endif
3070         };
3071         char tmp[MIGRATE_TYPES + 1];
3072         char *p = tmp;
3073         int i;
3074 
3075         for (i = 0; i < MIGRATE_TYPES; i++) {
3076                 if (type & (1 << i))
3077                         *p++ = types[i];
3078         }
3079 
3080         *p = '\0';
3081         printk("(%s) ", tmp);
3082 }
3083 
3084 /*
3085  * Show free area list (used inside shift_scroll-lock stuff)
3086  * We also calculate the percentage fragmentation. We do this by counting the
3087  * memory on each free list with the exception of the first item on the list.
3088  * Suppresses nodes that are not allowed by current's cpuset if
3089  * SHOW_MEM_FILTER_NODES is passed.
3090  */
3091 void show_free_areas(unsigned int filter)
3092 {
3093         int cpu;
3094         struct zone *zone;
3095 
3096         for_each_populated_zone(zone) {
3097                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
3098                         continue;
3099                 show_node(zone);
3100                 printk("%s per-cpu:\n", zone->name);
3101 
3102                 for_each_online_cpu(cpu) {
3103                         struct per_cpu_pageset *pageset;
3104 
3105                         pageset = per_cpu_ptr(zone->pageset, cpu);
3106 
3107                         printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
3108                                cpu, pageset->pcp.high,
3109                                pageset->pcp.batch, pageset->pcp.count);
3110                 }
3111         }
3112 
3113         printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
3114                 " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
3115                 " unevictable:%lu"
3116                 " dirty:%lu writeback:%lu unstable:%lu\n"
3117                 " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
3118                 " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
3119                 " free_cma:%lu\n",
3120                 global_page_state(NR_ACTIVE_ANON),
3121                 global_page_state(NR_INACTIVE_ANON),
3122                 global_page_state(NR_ISOLATED_ANON),
3123                 global_page_state(NR_ACTIVE_FILE),
3124                 global_page_state(NR_INACTIVE_FILE),
3125                 global_page_state(NR_ISOLATED_FILE),
3126                 global_page_state(NR_UNEVICTABLE),
3127                 global_page_state(NR_FILE_DIRTY),
3128                 global_page_state(NR_WRITEBACK),
3129                 global_page_state(NR_UNSTABLE_NFS),
3130                 global_page_state(NR_FREE_PAGES),
3131                 global_page_state(NR_SLAB_RECLAIMABLE),
3132                 global_page_state(NR_SLAB_UNRECLAIMABLE),
3133                 global_page_state(NR_FILE_MAPPED),
3134                 global_page_state(NR_SHMEM),
3135                 global_page_state(NR_PAGETABLE),
3136                 global_page_state(NR_BOUNCE),
3137                 global_page_state(NR_FREE_CMA_PAGES));
3138 
3139         for_each_populated_zone(zone) {
3140                 int i;
3141 
3142                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
3143                         continue;
3144                 show_node(zone);
3145                 printk("%s"
3146                         " free:%lukB"
3147                         " min:%lukB"
3148                         " low:%lukB"
3149                         " high:%lukB"
3150                         " active_anon:%lukB"
3151                         " inactive_anon:%lukB"
3152                         " active_file:%lukB"
3153                         " inactive_file:%lukB"
3154                         " unevictable:%lukB"
3155                         " isolated(anon):%lukB"
3156                         " isolated(file):%lukB"
3157                         " present:%lukB"
3158                         " managed:%lukB"
3159                         " mlocked:%lukB"
3160                         " dirty:%lukB"
3161                         " writeback:%lukB"
3162                         " mapped:%lukB"
3163                         " shmem:%lukB"
3164                         " slab_reclaimable:%lukB"
3165                         " slab_unreclaimable:%lukB"
3166                         " kernel_stack:%lukB"
3167                         " pagetables:%lukB"
3168                         " unstable:%lukB"
3169                         " bounce:%lukB"
3170                         " free_cma:%lukB"
3171                         " writeback_tmp:%lukB"
3172                         " pages_scanned:%lu"
3173                         " all_unreclaimable? %s"
3174                         "\n",
3175                         zone->name,
3176                         K(zone_page_state(zone, NR_FREE_PAGES)),
3177                         K(min_wmark_pages(zone)),
3178                         K(low_wmark_pages(zone)),
3179                         K(high_wmark_pages(zone)),
3180                         K(zone_page_state(zone, NR_ACTIVE_ANON)),
3181                         K(zone_page_state(zone, NR_INACTIVE_ANON)),
3182                         K(zone_page_state(zone, NR_ACTIVE_FILE)),
3183                         K(zone_page_state(zone, NR_INACTIVE_FILE)),
3184                         K(zone_page_state(zone, NR_UNEVICTABLE)),
3185                         K(zone_page_state(zone, NR_ISOLATED_ANON)),
3186                         K(zone_page_state(zone, NR_ISOLATED_FILE)),
3187                         K(zone->present_pages),
3188                         K(zone->managed_pages),
3189                         K(zone_page_state(zone, NR_MLOCK)),
3190                         K(zone_page_state(zone, NR_FILE_DIRTY)),
3191                         K(zone_page_state(zone, NR_WRITEBACK)),
3192                         K(zone_page_state(zone, NR_FILE_MAPPED)),
3193                         K(zone_page_state(zone, NR_SHMEM)),
3194                         K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
3195                         K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
3196                         zone_page_state(zone, NR_KERNEL_STACK) *
3197                                 THREAD_SIZE / 1024,
3198                         K(zone_page_state(zone, NR_PAGETABLE)),
3199                         K(zone_page_state(zone, NR_UNSTABLE_NFS)),
3200                         K(zone_page_state(zone, NR_BOUNCE)),
3201                         K(zone_page_state(zone, NR_FREE_CMA_PAGES)),
3202                         K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
3203                         zone->pages_scanned,
3204                         (!zone_reclaimable(zone) ? "yes" : "no")
3205                         );
3206                 printk("lowmem_reserve[]:");
3207                 for (i = 0; i < MAX_NR_ZONES; i++)
3208                         printk(" %lu", zone->lowmem_reserve[i]);
3209                 printk("\n");
3210         }
3211 
3212         for_each_populated_zone(zone) {
3213                 unsigned long nr[MAX_ORDER], flags, order, total = 0;
3214                 unsigned char types[MAX_ORDER];
3215 
3216                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
3217                         continue;
3218                 show_node(zone);
3219                 printk("%s: ", zone->name);
3220 
3221                 spin_lock_irqsave(&zone->lock, flags);
3222                 for (order = 0; order < MAX_ORDER; order++) {
3223                         struct free_area *area = &zone->free_area[order];
3224                         int type;
3225 
3226                         nr[order] = area->nr_free;
3227                         total += nr[order] << order;
3228 
3229                         types[order] = 0;
3230                         for (type = 0; type < MIGRATE_TYPES; type++) {
3231                                 if (!list_empty(&area->free_list[type]))
3232                                         types[order] |= 1 << type;
3233                         }
3234                 }
3235                 spin_unlock_irqrestore(&zone->lock, flags);
3236                 for (order = 0; order < MAX_ORDER; order++) {
3237                         printk("%lu*%lukB ", nr[order], K(1UL) << order);
3238                         if (nr[order])
3239                                 show_migration_types(types[order]);
3240                 }
3241                 printk("= %lukB\n", K(total));
3242         }
3243 
3244         hugetlb_show_meminfo();
3245 
3246         printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
3247 
3248         show_swap_cache_info();
3249 }
3250 
3251 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
3252 {
3253         zoneref->zone = zone;
3254         zoneref->zone_idx = zone_idx(zone);
3255 }
3256 
3257 /*
3258  * Builds allocation fallback zone lists.
3259  *
3260  * Add all populated zones of a node to the zonelist.
3261  */
3262 static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
3263                                 int nr_zones)
3264 {
3265         struct zone *zone;
3266         enum zone_type zone_type = MAX_NR_ZONES;
3267 
3268         do {
3269                 zone_type--;
3270                 zone = pgdat->node_zones + zone_type;
3271                 if (populated_zone(zone)) {
3272                         zoneref_set_zone(zone,
3273                                 &zonelist->_zonerefs[nr_zones++]);
3274                         check_highest_zone(zone_type);
3275                 }
3276         } while (zone_type);
3277 
3278         return nr_zones;
3279 }
3280 
3281 
3282 /*
3283  *  zonelist_order:
3284  *  0 = automatic detection of better ordering.
3285  *  1 = order by ([node] distance, -zonetype)
3286  *  2 = order by (-zonetype, [node] distance)
3287  *
3288  *  If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
3289  *  the same zonelist. So only NUMA can configure this param.
3290  */
3291 #define ZONELIST_ORDER_DEFAULT  0
3292 #define ZONELIST_ORDER_NODE     1
3293 #define ZONELIST_ORDER_ZONE     2
3294 
3295 /* zonelist order in the kernel.
3296  * set_zonelist_order() will set this to NODE or ZONE.
3297  */
3298 static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
3299 static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
3300 
3301 
3302 #ifdef CONFIG_NUMA
3303 /* The value user specified ....changed by config */
3304 static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
3305 /* string for sysctl */
3306 #define NUMA_ZONELIST_ORDER_LEN 16
3307 char numa_zonelist_order[16] = "default";
3308 
3309 /*
3310  * interface for configure zonelist ordering.
3311  * command line option "numa_zonelist_order"
3312  *      = "[dD]efault   - default, automatic configuration.
3313  *      = "[nN]ode      - order by node locality, then by zone within node
3314  *      = "[zZ]one      - order by zone, then by locality within zone
3315  */
3316 
3317 static int __parse_numa_zonelist_order(char *s)
3318 {
3319         if (*s == 'd' || *s == 'D') {
3320                 user_zonelist_order = ZONELIST_ORDER_DEFAULT;
3321         } else if (*s == 'n' || *s == 'N') {
3322                 user_zonelist_order = ZONELIST_ORDER_NODE;
3323         } else if (*s == 'z' || *s == 'Z') {
3324                 user_zonelist_order = ZONELIST_ORDER_ZONE;
3325         } else {
3326                 printk(KERN_WARNING
3327                         "Ignoring invalid numa_zonelist_order value:  "
3328                         "%s\n", s);
3329                 return -EINVAL;
3330         }
3331         return 0;
3332 }
3333 
3334 static __init int setup_numa_zonelist_order(char *s)
3335 {
3336         int ret;
3337 
3338         if (!s)
3339                 return 0;
3340 
3341         ret = __parse_numa_zonelist_order(s);
3342         if (ret == 0)
3343                 strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
3344 
3345         return ret;
3346 }
3347 early_param("numa_zonelist_order", setup_numa_zonelist_order);
3348 
3349 /*
3350  * sysctl handler for numa_zonelist_order
3351  */
3352 int numa_zonelist_order_handler(ctl_table *table, int write,
3353                 void __user *buffer, size_t *length,
3354                 loff_t *ppos)
3355 {
3356         char saved_string[NUMA_ZONELIST_ORDER_LEN];
3357         int ret;
3358         static DEFINE_MUTEX(zl_order_mutex);
3359 
3360         mutex_lock(&zl_order_mutex);
3361         if (write) {
3362                 if (strlen((char *)table->data) >= NUMA_ZONELIST_ORDER_LEN) {
3363                         ret = -EINVAL;
3364                         goto out;
3365                 }
3366                 strcpy(saved_string, (char *)table->data);
3367         }
3368         ret = proc_dostring(table, write, buffer, length, ppos);
3369         if (ret)
3370                 goto out;
3371         if (write) {
3372                 int oldval = user_zonelist_order;
3373 
3374                 ret = __parse_numa_zonelist_order((char *)table->data);
3375                 if (ret) {
3376                         /*
3377                          * bogus value.  restore saved string
3378                          */
3379                         strncpy((char *)table->data, saved_string,
3380                                 NUMA_ZONELIST_ORDER_LEN);
3381                         user_zonelist_order = oldval;
3382                 } else if (oldval != user_zonelist_order) {
3383                         mutex_lock(&zonelists_mutex);
3384                         build_all_zonelists(NULL, NULL);
3385                         mutex_unlock(&zonelists_mutex);
3386                 }
3387         }
3388 out:
3389         mutex_unlock(&zl_order_mutex);
3390         return ret;
3391 }
3392 
3393 
3394 #define MAX_NODE_LOAD (nr_online_nodes)
3395 static int node_load[MAX_NUMNODES];
3396 
3397 /**
3398  * find_next_best_node - find the next node that should appear in a given node's fallback list
3399  * @node: node whose fallback list we're appending
3400  * @used_node_mask: nodemask_t of already used nodes
3401  *
3402  * We use a number of factors to determine which is the next node that should
3403  * appear on a given node's fallback list.  The node should not have appeared
3404  * already in @node's fallback list, and it should be the next closest node
3405  * according to the distance array (which contains arbitrary distance values
3406  * from each node to each node in the system), and should also prefer nodes
3407  * with no CPUs, since presumably they'll have very little allocation pressure
3408  * on them otherwise.
3409  * It returns -1 if no node is found.
3410  */
3411 static int find_next_best_node(int node, nodemask_t *used_node_mask)
3412 {
3413         int n, val;
3414         int min_val = INT_MAX;
3415         int best_node = NUMA_NO_NODE;
3416         const struct cpumask *tmp = cpumask_of_node(0);
3417 
3418         /* Use the local node if we haven't already */
3419         if (!node_isset(node, *used_node_mask)) {
3420                 node_set(node, *used_node_mask);
3421                 return node;
3422         }
3423 
3424         for_each_node_state(n, N_MEMORY) {
3425 
3426                 /* Don't want a node to appear more than once */
3427                 if (node_isset(n, *used_node_mask))
3428                         continue;
3429 
3430                 /* Use the distance array to find the distance */
3431                 val = node_distance(node, n);
3432 
3433                 /* Penalize nodes under us ("prefer the next node") */
3434                 val += (n < node);
3435 
3436                 /* Give preference to headless and unused nodes */
3437                 tmp = cpumask_of_node(n);
3438                 if (!cpumask_empty(tmp))
3439                         val += PENALTY_FOR_NODE_WITH_CPUS;
3440 
3441                 /* Slight preference for less loaded node */
3442                 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
3443                 val += node_load[n];
3444 
3445                 if (val < min_val) {
3446                         min_val = val;
3447                         best_node = n;
3448                 }
3449         }
3450 
3451         if (best_node >= 0)
3452                 node_set(best_node, *used_node_mask);
3453 
3454         return best_node;
3455 }
3456 
3457 
3458 /*
3459  * Build zonelists ordered by node and zones within node.
3460  * This results in maximum locality--normal zone overflows into local
3461  * DMA zone, if any--but risks exhausting DMA zone.
3462  */
3463 static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
3464 {
3465         int j;
3466         struct zonelist *zonelist;
3467 
3468         zonelist = &pgdat->node_zonelists[0];
3469         for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
3470                 ;
3471         j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3472         zonelist->_zonerefs[j].zone = NULL;
3473         zonelist->_zonerefs[j].zone_idx = 0;
3474 }
3475 
3476 /*
3477  * Build gfp_thisnode zonelists
3478  */
3479 static void build_thisnode_zonelists(pg_data_t *pgdat)
3480 {
3481         int j;
3482         struct zonelist *zonelist;
3483 
3484         zonelist = &pgdat->node_zonelists[1];
3485         j = build_zonelists_node(pgdat, zonelist, 0);
3486         zonelist->_zonerefs[j].zone = NULL;
3487         zonelist->_zonerefs[j].zone_idx = 0;
3488 }
3489 
3490 /*
3491  * Build zonelists ordered by zone and nodes within zones.
3492  * This results in conserving DMA zone[s] until all Normal memory is
3493  * exhausted, but results in overflowing to remote node while memory
3494  * may still exist in local DMA zone.
3495  */
3496 static int node_order[MAX_NUMNODES];
3497 
3498 static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
3499 {
3500         int pos, j, node;
3501         int zone_type;          /* needs to be signed */
3502         struct zone *z;
3503         struct zonelist *zonelist;
3504 
3505         zonelist = &pgdat->node_zonelists[0];
3506         pos = 0;
3507         for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
3508                 for (j = 0; j < nr_nodes; j++) {
3509                         node = node_order[j];
3510                         z = &NODE_DATA(node)->node_zones[zone_type];
3511                         if (populated_zone(z)) {
3512                                 zoneref_set_zone(z,
3513                                         &zonelist->_zonerefs[pos++]);
3514                                 check_highest_zone(zone_type);
3515                         }
3516                 }
3517         }
3518         zonelist->_zonerefs[pos].zone = NULL;
3519         zonelist->_zonerefs[pos].zone_idx = 0;
3520 }
3521 
3522 static int default_zonelist_order(void)
3523 {
3524         int nid, zone_type;
3525         unsigned long low_kmem_size, total_size;
3526         struct zone *z;
3527         int average_size;
3528         /*
3529          * ZONE_DMA and ZONE_DMA32 can be very small area in the system.
3530          * If they are really small and used heavily, the system can fall
3531          * into OOM very easily.
3532          * This function detect ZONE_DMA/DMA32 size and configures zone order.
3533          */
3534         /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
3535         low_kmem_size = 0;
3536         total_size = 0;
3537         for_each_online_node(nid) {
3538                 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3539                         z = &NODE_DATA(nid)->node_zones[zone_type];
3540                         if (populated_zone(z)) {
3541                                 if (zone_type < ZONE_NORMAL)
3542                                         low_kmem_size += z->managed_pages;
3543                                 total_size += z->managed_pages;
3544                         } else if (zone_type == ZONE_NORMAL) {
3545                                 /*
3546                                  * If any node has only lowmem, then node order
3547                                  * is preferred to allow kernel allocations
3548                                  * locally; otherwise, they can easily infringe
3549                                  * on other nodes when there is an abundance of
3550                                  * lowmem available to allocate from.
3551                                  */
3552                                 return ZONELIST_ORDER_NODE;
3553                         }
3554                 }
3555         }
3556         if (!low_kmem_size ||  /* there are no DMA area. */
3557             low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
3558                 return ZONELIST_ORDER_NODE;
3559         /*
3560          * look into each node's config.
3561          * If there is a node whose DMA/DMA32 memory is very big area on
3562          * local memory, NODE_ORDER may be suitable.
3563          */
3564         average_size = total_size /
3565                                 (nodes_weight(node_states[N_MEMORY]) + 1);
3566         for_each_online_node(nid) {
3567                 low_kmem_size = 0;
3568                 total_size = 0;
3569                 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3570                         z = &NODE_DATA(nid)->node_zones[zone_type];
3571                         if (populated_zone(z)) {
3572                                 if (zone_type < ZONE_NORMAL)
3573                                         low_kmem_size += z->present_pages;
3574                                 total_size += z->present_pages;
3575                         }
3576                 }
3577                 if (low_kmem_size &&
3578                     total_size > average_size && /* ignore small node */
3579                     low_kmem_size > total_size * 70/100)
3580                         return ZONELIST_ORDER_NODE;
3581         }
3582         return ZONELIST_ORDER_ZONE;
3583 }
3584 
3585 static void set_zonelist_order(void)
3586 {
3587         if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
3588                 current_zonelist_order = default_zonelist_order();
3589         else
3590                 current_zonelist_order = user_zonelist_order;
3591 }
3592 
3593 static void build_zonelists(pg_data_t *pgdat)
3594 {
3595         int j, node, load;
3596         enum zone_type i;
3597         nodemask_t used_mask;
3598         int local_node, prev_node;
3599         struct zonelist *zonelist;
3600         int order = current_zonelist_order;
3601 
3602         /* initialize zonelists */
3603         for (i = 0; i < MAX_ZONELISTS; i++) {
3604                 zonelist = pgdat->node_zonelists + i;
3605                 zonelist->_zonerefs[0].zone = NULL;
3606                 zonelist->_zonerefs[0].zone_idx = 0;
3607         }
3608 
3609         /* NUMA-aware ordering of nodes */
3610         local_node = pgdat->node_id;
3611         load = nr_online_nodes;
3612         prev_node = local_node;
3613         nodes_clear(used_mask);
3614 
3615         memset(node_order, 0, sizeof(node_order));
3616         j = 0;
3617 
3618         while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
3619                 /*
3620                  * We don't want to pressure a particular node.
3621                  * So adding penalty to the first node in same
3622                  * distance group to make it round-robin.
3623                  */
3624                 if (node_distance(local_node, node) !=
3625                     node_distance(local_node, prev_node))
3626                         node_load[node] = load;
3627 
3628                 prev_node = node;
3629                 load--;
3630                 if (order == ZONELIST_ORDER_NODE)
3631                         build_zonelists_in_node_order(pgdat, node);
3632                 else
3633                         node_order[j++] = node; /* remember order */
3634         }
3635 
3636         if (order == ZONELIST_ORDER_ZONE) {
3637                 /* calculate node order -- i.e., DMA last! */
3638                 build_zonelists_in_zone_order(pgdat, j);
3639         }
3640 
3641         build_thisnode_zonelists(pgdat);
3642 }
3643 
3644 /* Construct the zonelist performance cache - see further mmzone.h */
3645 static void build_zonelist_cache(pg_data_t *pgdat)
3646 {
3647         struct zonelist *zonelist;
3648         struct zonelist_cache *zlc;
3649         struct zoneref *z;
3650 
3651         zonelist = &pgdat->node_zonelists[0];
3652         zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
3653         bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
3654         for (z = zonelist->_zonerefs; z->zone; z++)
3655                 zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
3656 }
3657 
3658 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
3659 /*
3660  * Return node id of node used for "local" allocations.
3661  * I.e., first node id of first zone in arg node's generic zonelist.
3662  * Used for initializing percpu 'numa_mem', which is used primarily
3663  * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
3664  */
3665 int local_memory_node(int node)
3666 {
3667         struct zone *zone;
3668 
3669         (void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
3670                                    gfp_zone(GFP_KERNEL),
3671                                    NULL,
3672                                    &zone);
3673         return zone->node;
3674 }
3675 #endif
3676 
3677 #else   /* CONFIG_NUMA */
3678 
3679 static void set_zonelist_order(void)
3680 {
3681         current_zonelist_order = ZONELIST_ORDER_ZONE;
3682 }
3683 
3684 static void build_zonelists(pg_data_t *pgdat)
3685 {
3686         int node, local_node;
3687         enum zone_type j;
3688         struct zonelist *zonelist;
3689 
3690         local_node = pgdat->node_id;
3691 
3692         zonelist = &pgdat->node_zonelists[0];
3693         j = build_zonelists_node(pgdat, zonelist, 0);
3694 
3695         /*
3696          * Now we build the zonelist so that it contains the zones
3697          * of all the other nodes.
3698          * We don't want to pressure a particular node, so when
3699          * building the zones for node N, we make sure that the
3700          * zones coming right after the local ones are those from
3701          * node N+1 (modulo N)
3702          */
3703         for (node = local_node + 1; node < MAX_NUMNODES; node++) {
3704                 if (!node_online(node))
3705                         continue;
3706                 j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3707         }
3708         for (node = 0; node < local_node; node++) {
3709                 if (!node_online(node))
3710                         continue;
3711                 j = build_zonelists_node(NODE_DATA(node), zonelist, j);
3712         }
3713 
3714         zonelist->_zonerefs[j].zone = NULL;
3715         zonelist->_zonerefs[j].zone_idx = 0;
3716 }
3717 
3718 /* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
3719 static void build_zonelist_cache(pg_data_t *pgdat)
3720 {
3721         pgdat->node_zonelists[0].zlcache_ptr = NULL;
3722 }
3723 
3724 #endif  /* CONFIG_NUMA */
3725 
3726 /*
3727  * Boot pageset table. One per cpu which is going to be used for all
3728  * zones and all nodes. The parameters will be set in such a way
3729  * that an item put on a list will immediately be handed over to
3730  * the buddy list. This is safe since pageset manipulation is done
3731  * with interrupts disabled.
3732  *
3733  * The boot_pagesets must be kept even after bootup is complete for
3734  * unused processors and/or zones. They do play a role for bootstrapping
3735  * hotplugged processors.
3736  *
3737  * zoneinfo_show() and maybe other functions do
3738  * not check if the processor is online before following the pageset pointer.
3739  * Other parts of the kernel may not check if the zone is available.
3740  */
3741 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
3742 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
3743 static void setup_zone_pageset(struct zone *zone);
3744 
3745 /*
3746  * Global mutex to protect against size modification of zonelists
3747  * as well as to serialize pageset setup for the new populated zone.
3748  */
3749 DEFINE_MUTEX(zonelists_mutex);
3750 
3751 /* return values int ....just for stop_machine() */
3752 static int __build_all_zonelists(void *data)
3753 {
3754         int nid;
3755         int cpu;
3756         pg_data_t *self = data;
3757 
3758 #ifdef CONFIG_NUMA
3759         memset(node_load, 0, sizeof(node_load));
3760 #endif
3761 
3762         if (self && !node_online(self->node_id)) {
3763                 build_zonelists(self);
3764                 build_zonelist_cache(self);
3765         }
3766 
3767         for_each_online_node(nid) {
3768                 pg_data_t *pgdat = NODE_DATA(nid);
3769 
3770                 build_zonelists(pgdat);
3771                 build_zonelist_cache(pgdat);
3772         }
3773 
3774         /*
3775          * Initialize the boot_pagesets that are going to be used
3776          * for bootstrapping processors. The real pagesets for
3777          * each zone will be allocated later when the per cpu
3778          * allocator is available.
3779          *
3780          * boot_pagesets are used also for bootstrapping offline
3781          * cpus if the system is already booted because the pagesets
3782          * are needed to initialize allocators on a specific cpu too.
3783          * F.e. the percpu allocator needs the page allocator which
3784          * needs the percpu allocator in order to allocate its pagesets
3785          * (a chicken-egg dilemma).
3786          */
3787         for_each_possible_cpu(cpu) {
3788                 setup_pageset(&per_cpu(boot_pageset, cpu), 0);
3789 
3790 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
3791                 /*
3792                  * We now know the "local memory node" for each node--
3793                  * i.e., the node of the first zone in the generic zonelist.
3794                  * Set up numa_mem percpu variable for on-line cpus.  During
3795                  * boot, only the boot cpu should be on-line;  we'll init the
3796                  * secondary cpus' numa_mem as they come on-line.  During
3797                  * node/memory hotplug, we'll fixup all on-line cpus.
3798                  */
3799                 if (cpu_online(cpu))
3800                         set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
3801 #endif
3802         }
3803 
3804         return 0;
3805 }
3806 
3807 /*
3808  * Called with zonelists_mutex held always
3809  * unless system_state == SYSTEM_BOOTING.
3810  */
3811 void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone)
3812 {
3813         set_zonelist_order();
3814 
3815         if (system_state == SYSTEM_BOOTING) {
3816                 __build_all_zonelists(NULL);
3817                 mminit_verify_zonelist();
3818                 cpuset_init_current_mems_allowed();
3819         } else {
3820 #ifdef CONFIG_MEMORY_HOTPLUG
3821                 if (zone)
3822                         setup_zone_pageset(zone);
3823 #endif
3824                 /* we have to stop all cpus to guarantee there is no user
3825                    of zonelist */
3826                 stop_machine(__build_all_zonelists, pgdat, NULL);
3827                 /* cpuset refresh routine should be here */
3828         }
3829         vm_total_pages = nr_free_pagecache_pages();
3830         /*
3831          * Disable grouping by mobility if the number of pages in the
3832          * system is too low to allow the mechanism to work. It would be
3833          * more accurate, but expensive to check per-zone. This check is
3834          * made on memory-hotadd so a system can start with mobility
3835          * disabled and enable it later
3836          */
3837         if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
3838                 page_group_by_mobility_disabled = 1;
3839         else
3840                 page_group_by_mobility_disabled = 0;
3841 
3842         printk("Built %i zonelists in %s order, mobility grouping %s.  "
3843                 "Total pages: %ld\n",
3844                         nr_online_nodes,
3845                         zonelist_order_name[current_zonelist_order],
3846                         page_group_by_mobility_disabled ? "off" : "on",
3847                         vm_total_pages);
3848 #ifdef CONFIG_NUMA
3849         printk("Policy zone: %s\n", zone_names[policy_zone]);
3850 #endif
3851 }
3852 
3853 /*
3854  * Helper functions to size the waitqueue hash table.
3855  * Essentially these want to choose hash table sizes sufficiently
3856  * large so that collisions trying to wait on pages are rare.
3857  * But in fact, the number of active page waitqueues on typical
3858  * systems is ridiculously low, less than 200. So this is even
3859  * conservative, even though it seems large.
3860  *
3861  * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
3862  * waitqueues, i.e. the size of the waitq table given the number of pages.
3863  */
3864 #define PAGES_PER_WAITQUEUE     256
3865 
3866 #ifndef CONFIG_MEMORY_HOTPLUG
3867 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3868 {
3869         unsigned long size = 1;
3870 
3871         pages /= PAGES_PER_WAITQUEUE;
3872 
3873         while (size < pages)
3874                 size <<= 1;
3875 
3876         /*
3877          * Once we have dozens or even hundreds of threads sleeping
3878          * on IO we've got bigger problems than wait queue collision.
3879          * Limit the size of the wait table to a reasonable size.
3880          */
3881         size = min(size, 4096UL);
3882 
3883         return max(size, 4UL);
3884 }
3885 #else
3886 /*
3887  * A zone's size might be changed by hot-add, so it is not possible to determine
3888  * a suitable size for its wait_table.  So we use the maximum size now.
3889  *
3890  * The max wait table size = 4096 x sizeof(wait_queue_head_t).   ie:
3891  *
3892  *    i386 (preemption config)    : 4096 x 16 = 64Kbyte.
3893  *    ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
3894  *    ia64, x86-64 (preemption)   : 4096 x 24 = 96Kbyte.
3895  *
3896  * The maximum entries are prepared when a zone's memory is (512K + 256) pages
3897  * or more by the traditional way. (See above).  It equals:
3898  *
3899  *    i386, x86-64, powerpc(4K page size) : =  ( 2G + 1M)byte.
3900  *    ia64(16K page size)                 : =  ( 8G + 4M)byte.
3901  *    powerpc (64K page size)             : =  (32G +16M)byte.
3902  */
3903 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3904 {
3905         return 4096UL;
3906 }
3907 #endif
3908 
3909 /*
3910  * This is an integer logarithm so that shifts can be used later
3911  * to extract the more random high bits from the multiplicative
3912  * hash function before the remainder is taken.
3913  */
3914 static inline unsigned long wait_table_bits(unsigned long size)
3915 {
3916         return ffz(~size);
3917 }
3918 
3919 /*
3920  * Check if a pageblock contains reserved pages
3921  */
3922 static int pageblock_is_reserved(unsigned long start_pfn, unsigned long end_pfn)
3923 {
3924         unsigned long pfn;
3925 
3926         for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3927                 if (!pfn_valid_within(pfn) || PageReserved(pfn_to_page(pfn)))
3928                         return 1;
3929         }
3930         return 0;
3931 }
3932 
3933 /*
3934  * Mark a number of pageblocks as MIGRATE_RESERVE. The number
3935  * of blocks reserved is based on min_wmark_pages(zone). The memory within
3936  * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
3937  * higher will lead to a bigger reserve which will get freed as contiguous
3938  * blocks as reclaim kicks in
3939  */
3940 static void setup_zone_migrate_reserve(struct zone *zone)
3941 {
3942         unsigned long start_pfn, pfn, end_pfn, block_end_pfn;
3943         struct page *page;
3944         unsigned long block_migratetype;
3945         int reserve;
3946         int old_reserve;
3947 
3948         /*
3949          * Get the start pfn, end pfn and the number of blocks to reserve
3950          * We have to be careful to be aligned to pageblock_nr_pages to
3951          * make sure that we always check pfn_valid for the first page in
3952          * the block.
3953          */
3954         start_pfn = zone->zone_start_pfn;
3955         end_pfn = zone_end_pfn(zone);
3956         start_pfn = roundup(start_pfn, pageblock_nr_pages);
3957         reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
3958                                                         pageblock_order;
3959 
3960         /*
3961          * Reserve blocks are generally in place to help high-order atomic
3962          * allocations that are short-lived. A min_free_kbytes value that
3963          * would result in more than 2 reserve blocks for atomic allocations
3964          * is assumed to be in place to help anti-fragmentation for the
3965          * future allocation of hugepages at runtime.
3966          */
3967         reserve = min(2, reserve);
3968         old_reserve = zone->nr_migrate_reserve_block;
3969 
3970         /* When memory hot-add, we almost always need to do nothing */
3971         if (reserve == old_reserve)
3972                 return;
3973         zone->nr_migrate_reserve_block = reserve;
3974 
3975         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
3976                 if (!pfn_valid(pfn))
3977                         continue;
3978                 page = pfn_to_page(pfn);
3979 
3980                 /* Watch out for overlapping nodes */
3981                 if (page_to_nid(page) != zone_to_nid(zone))
3982                         continue;
3983 
3984                 block_migratetype = get_pageblock_migratetype(page);
3985 
3986                 /* Only test what is necessary when the reserves are not met */
3987                 if (reserve > 0) {
3988                         /*
3989                          * Blocks with reserved pages will never free, skip
3990                          * them.
3991                          */
3992                         block_end_pfn = min(pfn + pageblock_nr_pages, end_pfn);
3993                         if (pageblock_is_reserved(pfn, block_end_pfn))
3994                                 continue;
3995 
3996                         /* If this block is reserved, account for it */
3997                         if (block_migratetype == MIGRATE_RESERVE) {
3998                                 reserve--;
3999                                 continue;
4000                         }
4001 
4002                         /* Suitable for reserving if this block is movable */
4003                         if (block_migratetype == MIGRATE_MOVABLE) {
4004                                 set_pageblock_migratetype(page,
4005                                                         MIGRATE_RESERVE);
4006                                 move_freepages_block(zone, page,
4007                                                         MIGRATE_RESERVE);
4008                                 reserve--;
4009                                 continue;
4010                         }
4011                 } else if (!old_reserve) {
4012                         /*
4013                          * At boot time we don't need to scan the whole zone
4014                          * for turning off MIGRATE_RESERVE.
4015                          */
4016                         break;
4017                 }
4018 
4019                 /*
4020                  * If the reserve is met and this is a previous reserved block,
4021                  * take it back
4022                  */
4023                 if (block_migratetype == MIGRATE_RESERVE) {
4024                         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
4025                         move_freepages_block(zone, page, MIGRATE_MOVABLE);
4026                 }
4027         }
4028 }
4029 
4030 /*
4031  * Initially all pages are reserved - free ones are freed
4032  * up by free_all_bootmem() once the early boot process is
4033  * done. Non-atomic initialization, single-pass.
4034  */
4035 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
4036                 unsigned long start_pfn, enum memmap_context context)
4037 {
4038         struct page *page;
4039         unsigned long end_pfn = start_pfn + size;
4040         unsigned long pfn;
4041         struct zone *z;
4042 
4043         if (highest_memmap_pfn < end_pfn - 1)
4044                 highest_memmap_pfn = end_pfn - 1;
4045 
4046         z = &NODE_DATA(nid)->node_zones[zone];
4047         for (pfn = start_pfn; pfn < end_pfn; pfn++) {
4048                 /*
4049                  * There can be holes in boot-time mem_map[]s
4050                  * handed to this function.  They do not
4051                  * exist on hotplugged memory.
4052                  */
4053                 if (context == MEMMAP_EARLY) {
4054                         if (!early_pfn_valid(pfn))
4055                                 continue;
4056                         if (!early_pfn_in_nid(pfn, nid))
4057                                 continue;
4058                 }
4059                 page = pfn_to_page(pfn);
4060                 set_page_links(page, zone, nid, pfn);
4061                 mminit_verify_page_links(page, zone, nid, pfn);
4062                 init_page_count(page);
4063                 page_mapcount_reset(page);
4064                 page_cpupid_reset_last(page);
4065                 SetPageReserved(page);
4066                 /*
4067                  * Mark the block movable so that blocks are reserved for
4068                  * movable at startup. This will force kernel allocations
4069                  * to reserve their blocks rather than leaking throughout
4070                  * the address space during boot when many long-lived
4071                  * kernel allocations are made. Later some blocks near
4072                  * the start are marked MIGRATE_RESERVE by
4073                  * setup_zone_migrate_reserve()
4074                  *
4075                  * bitmap is created for zone's valid pfn range. but memmap
4076                  * can be created for invalid pages (for alignment)
4077                  * check here not to call set_pageblock_migratetype() against
4078                  * pfn out of zone.
4079                  */
4080                 if ((z->zone_start_pfn <= pfn)
4081                     && (pfn < zone_end_pfn(z))
4082                     && !(pfn & (pageblock_nr_pages - 1)))
4083                         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
4084 
4085                 INIT_LIST_HEAD(&page->lru);
4086 #ifdef WANT_PAGE_VIRTUAL
4087                 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
4088                 if (!is_highmem_idx(zone))
4089                         set_page_address(page, __va(pfn << PAGE_SHIFT));
4090 #endif
4091         }
4092 }
4093 
4094 static void __meminit zone_init_free_lists(struct zone *zone)
4095 {
4096         int order, t;
4097         for_each_migratetype_order(order, t) {
4098                 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
4099                 zone->free_area[order].nr_free = 0;
4100         }
4101 }
4102 
4103 #ifndef __HAVE_ARCH_MEMMAP_INIT
4104 #define memmap_init(size, nid, zone, start_pfn) \
4105         memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
4106 #endif
4107 
4108 static int __meminit zone_batchsize(struct zone *zone)
4109 {
4110 #ifdef CONFIG_MMU
4111         int batch;
4112 
4113         /*
4114          * The per-cpu-pages pools are set to around 1000th of the
4115          * size of the zone.  But no more than 1/2 of a meg.
4116          *
4117          * OK, so we don't know how big the cache is.  So guess.
4118          */
4119         batch = zone->managed_pages / 1024;
4120         if (batch * PAGE_SIZE > 512 * 1024)
4121                 batch = (512 * 1024) / PAGE_SIZE;
4122         batch /= 4;             /* We effectively *= 4 below */
4123         if (batch < 1)
4124                 batch = 1;
4125 
4126         /*
4127          * Clamp the batch to a 2^n - 1 value. Having a power
4128          * of 2 value was found to be more likely to have
4129          * suboptimal cache aliasing properties in some cases.
4130          *
4131          * For example if 2 tasks are alternately allocating
4132          * batches of pages, one task can end up with a lot
4133          * of pages of one half of the possible page colors
4134          * and the other with pages of the other colors.
4135          */
4136         batch = rounddown_pow_of_two(batch + batch/2) - 1;
4137 
4138         return batch;
4139 
4140 #else
4141         /* The deferral and batching of frees should be suppressed under NOMMU
4142          * conditions.
4143          *
4144          * The problem is that NOMMU needs to be able to allocate large chunks
4145          * of contiguous memory as there's no hardware page translation to
4146          * assemble apparent contiguous memory from discontiguous pages.
4147          *
4148          * Queueing large contiguous runs of pages for batching, however,
4149          * causes the pages to actually be freed in smaller chunks.  As there
4150          * can be a significant delay between the individual batches being
4151          * recycled, this leads to the once large chunks of space being
4152          * fragmented and becoming unavailable for high-order allocations.
4153          */
4154         return 0;
4155 #endif
4156 }
4157 
4158 /*
4159  * pcp->high and pcp->batch values are related and dependent on one another:
4160  * ->batch must never be higher then ->high.
4161  * The following function updates them in a safe manner without read side
4162  * locking.
4163  *
4164  * Any new users of pcp->batch and pcp->high should ensure they can cope with
4165  * those fields changing asynchronously (acording the the above rule).
4166  *
4167  * mutex_is_locked(&pcp_batch_high_lock) required when calling this function
4168  * outside of boot time (or some other assurance that no concurrent updaters
4169  * exist).
4170  */
4171 static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
4172                 unsigned long batch)
4173 {
4174        /* start with a fail safe value for batch */
4175         pcp->batch = 1;
4176         smp_wmb();
4177 
4178        /* Update high, then batch, in order */
4179         pcp->high = high;
4180         smp_wmb();
4181 
4182         pcp->batch = batch;
4183 }
4184 
4185 /* a companion to pageset_set_high() */
4186 static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
4187 {
4188         pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
4189 }
4190 
4191 static void pageset_init(struct per_cpu_pageset *p)
4192 {
4193         struct per_cpu_pages *pcp;
4194         int migratetype;
4195 
4196         memset(p, 0, sizeof(*p));
4197 
4198         pcp = &p->pcp;
4199         pcp->count = 0;
4200         for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
4201                 INIT_LIST_HEAD(&pcp->lists[migratetype]);
4202 }
4203 
4204 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
4205 {
4206         pageset_init(p);
4207         pageset_set_batch(p, batch);
4208 }
4209 
4210 /*
4211  * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
4212  * to the value high for the pageset p.
4213  */
4214 static void pageset_set_high(struct per_cpu_pageset *p,
4215                                 unsigned long high)
4216 {
4217         unsigned long batch = max(1UL, high / 4);
4218         if ((high / 4) > (PAGE_SHIFT * 8))
4219                 batch = PAGE_SHIFT * 8;
4220 
4221         pageset_update(&p->pcp, high, batch);
4222 }
4223 
4224 static void __meminit pageset_set_high_and_batch(struct zone *zone,
4225                 struct per_cpu_pageset *pcp)
4226 {
4227         if (percpu_pagelist_fraction)
4228                 pageset_set_high(pcp,
4229                         (zone->managed_pages /
4230                                 percpu_pagelist_fraction));
4231         else
4232                 pageset_set_batch(pcp, zone_batchsize(zone));
4233 }
4234 
4235 static void __meminit zone_pageset_init(struct zone *zone, int cpu)
4236 {
4237         struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
4238 
4239         pageset_init(pcp);
4240         pageset_set_high_and_batch(zone, pcp);
4241 }
4242 
4243 static void __meminit setup_zone_pageset(struct zone *zone)
4244 {
4245         int cpu;
4246         zone->pageset = alloc_percpu(struct per_cpu_pageset);
4247         for_each_possible_cpu(cpu)
4248                 zone_pageset_init(zone, cpu);
4249 }
4250 
4251 /*
4252  * Allocate per cpu pagesets and initialize them.
4253  * Before this call only boot pagesets were available.
4254  */
4255 void __init setup_per_cpu_pageset(void)
4256 {
4257         struct zone *zone;
4258 
4259         for_each_populated_zone(zone)
4260                 setup_zone_pageset(zone);
4261 }
4262 
4263 static noinline __init_refok
4264 int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
4265 {
4266         int i;
4267         size_t alloc_size;
4268 
4269         /*
4270          * The per-page waitqueue mechanism uses hashed waitqueues
4271          * per zone.
4272          */
4273         zone->wait_table_hash_nr_entries =
4274                  wait_table_hash_nr_entries(zone_size_pages);
4275         zone->wait_table_bits =
4276                 wait_table_bits(zone->wait_table_hash_nr_entries);
4277         alloc_size = zone->wait_table_hash_nr_entries
4278                                         * sizeof(wait_queue_head_t);
4279 
4280         if (!slab_is_available()) {
4281                 zone->wait_table = (wait_queue_head_t *)
4282                         memblock_virt_alloc_node_nopanic(
4283                                 alloc_size, zone->zone_pgdat->node_id);
4284         } else {
4285                 /*
4286                  * This case means that a zone whose size was 0 gets new memory
4287                  * via memory hot-add.
4288                  * But it may be the case that a new node was hot-added.  In
4289                  * this case vmalloc() will not be able to use this new node's
4290                  * memory - this wait_table must be initialized to use this new
4291                  * node itself as well.
4292                  * To use this new node's memory, further consideration will be
4293                  * necessary.
4294                  */
4295                 zone->wait_table = vmalloc(alloc_size);
4296         }
4297         if (!zone->wait_table)
4298                 return -ENOMEM;
4299 
4300         for (i = 0; i < zone->wait_table_hash_nr_entries; ++i)
4301                 init_waitqueue_head(zone->wait_table + i);
4302 
4303         return 0;
4304 }
4305 
4306 static __meminit void zone_pcp_init(struct zone *zone)
4307 {
4308         /*
4309          * per cpu subsystem is not up at this point. The following code
4310          * relies on the ability of the linker to provide the
4311          * offset of a (static) per cpu variable into the per cpu area.
4312          */
4313         zone->pageset = &boot_pageset;
4314 
4315         if (populated_zone(zone))
4316                 printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%u\n",
4317                         zone->name, zone->present_pages,
4318                                          zone_batchsize(zone));
4319 }
4320 
4321 int __meminit init_currently_empty_zone(struct zone *zone,
4322                                         unsigned long zone_start_pfn,
4323                                         unsigned long size,
4324                                         enum memmap_context context)
4325 {
4326         struct pglist_data *pgdat = zone->zone_pgdat;
4327         int ret;
4328         ret = zone_wait_table_init(zone, size);
4329         if (ret)
4330                 return ret;
4331         pgdat->nr_zones = zone_idx(zone) + 1;
4332 
4333         zone->zone_start_pfn = zone_start_pfn;
4334 
4335         mminit_dprintk(MMINIT_TRACE, "memmap_init",
4336                         "Initialising map node %d zone %lu pfns %lu -> %lu\n",
4337                         pgdat->node_id,
4338                         (unsigned long)zone_idx(zone),
4339                         zone_start_pfn, (zone_start_pfn + size));
4340 
4341         zone_init_free_lists(zone);
4342 
4343         return 0;
4344 }
4345 
4346 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4347 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
4348 /*
4349  * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
4350  * Architectures may implement their own version but if add_active_range()
4351  * was used and there are no special requirements, this is a convenient
4352  * alternative
4353  */
4354 int __meminit __early_pfn_to_nid(unsigned long pfn)
4355 {
4356         unsigned long start_pfn, end_pfn;
4357         int nid;
4358         /*
4359          * NOTE: The following SMP-unsafe globals are only used early in boot
4360          * when the kernel is running single-threaded.
4361          */
4362         static unsigned long __meminitdata last_start_pfn, last_end_pfn;
4363         static int __meminitdata last_nid;
4364 
4365         if (last_start_pfn <= pfn && pfn < last_end_pfn)
4366                 return last_nid;
4367 
4368         nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
4369         if (nid != -1) {
4370                 last_start_pfn = start_pfn;
4371                 last_end_pfn = end_pfn;
4372                 last_nid = nid;
4373         }
4374 
4375         return nid;
4376 }
4377 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
4378 
4379 int __meminit early_pfn_to_nid(unsigned long pfn)
4380 {
4381         int nid;
4382 
4383         nid = __early_pfn_to_nid(pfn);
4384         if (nid >= 0)
4385                 return nid;
4386         /* just returns 0 */
4387         return 0;
4388 }
4389 
4390 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
4391 bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
4392 {
4393         int nid;
4394 
4395         nid = __early_pfn_to_nid(pfn);
4396         if (nid >= 0 && nid != node)
4397                 return false;
4398         return true;
4399 }
4400 #endif
4401 
4402 /**
4403  * free_bootmem_with_active_regions - Call memblock_free_early_nid for each active range
4404  * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
4405  * @max_low_pfn: The highest PFN that will be passed to memblock_free_early_nid
4406  *
4407  * If an architecture guarantees that all ranges registered with
4408  * add_active_ranges() contain no holes and may be freed, this
4409  * this function may be used instead of calling memblock_free_early_nid()
4410  * manually.
4411  */
4412 void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
4413 {
4414         unsigned long start_pfn, end_pfn;
4415         int i, this_nid;
4416 
4417         for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
4418                 start_pfn = min(start_pfn, max_low_pfn);
4419                 end_pfn = min(end_pfn, max_low_pfn);
4420 
4421                 if (start_pfn < end_pfn)
4422                         memblock_free_early_nid(PFN_PHYS(start_pfn),
4423                                         (end_pfn - start_pfn) << PAGE_SHIFT,
4424                                         this_nid);
4425         }
4426 }
4427 
4428 /**
4429  * sparse_memory_present_with_active_regions - Call memory_present for each active range
4430  * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
4431  *
4432  * If an architecture guarantees that all ranges registered with
4433  * add_active_ranges() contain no holes and may be freed, this
4434  * function may be used instead of calling memory_present() manually.
4435  */
4436 void __init sparse_memory_present_with_active_regions(int nid)
4437 {
4438         unsigned long start_pfn, end_pfn;
4439         int i, this_nid;
4440 
4441         for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
4442                 memory_present(this_nid, start_pfn, end_pfn);
4443 }
4444 
4445 /**
4446  * get_pfn_range_for_nid - Return the start and end page frames for a node
4447  * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
4448  * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
4449  * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
4450  *
4451  * It returns the start and end page frame of a node based on information
4452  * provided by an arch calling add_active_range(). If called for a node
4453  * with no available memory, a warning is printed and the start and end
4454  * PFNs will be 0.
4455  */
4456 void __meminit get_pfn_range_for_nid(unsigned int nid,
4457                         unsigned long *start_pfn, unsigned long *end_pfn)
4458 {
4459         unsigned long this_start_pfn, this_end_pfn;
4460         int i;
4461 
4462         *start_pfn = -1UL;
4463         *end_pfn = 0;
4464 
4465         for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
4466                 *start_pfn = min(*start_pfn, this_start_pfn);
4467                 *end_pfn = max(*end_pfn, this_end_pfn);
4468         }
4469 
4470         if (*start_pfn == -1UL)
4471                 *start_pfn = 0;
4472 }
4473 
4474 /*
4475  * This finds a zone that can be used for ZONE_MOVABLE pages. The
4476  * assumption is made that zones within a node are ordered in monotonic
4477  * increasing memory addresses so that the "highest" populated zone is used
4478  */
4479 static void __init find_usable_zone_for_movable(void)
4480 {
4481         int zone_index;
4482         for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
4483                 if (zone_index == ZONE_MOVABLE)
4484                         continue;
4485 
4486                 if (arch_zone_highest_possible_pfn[zone_index] >
4487                                 arch_zone_lowest_possible_pfn[zone_index])
4488                         break;
4489         }
4490 
4491         VM_BUG_ON(zone_index == -1);
4492         movable_zone = zone_index;
4493 }
4494 
4495 /*
4496  * The zone ranges provided by the architecture do not include ZONE_MOVABLE
4497  * because it is sized independent of architecture. Unlike the other zones,
4498  * the starting point for ZONE_MOVABLE is not fixed. It may be different
4499  * in each node depending on the size of each node and how evenly kernelcore
4500  * is distributed. This helper function adjusts the zone ranges
4501  * provided by the architecture for a given node by using the end of the
4502  * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
4503  * zones within a node are in order of monotonic increases memory addresses
4504  */
4505 static void __meminit adjust_zone_range_for_zone_movable(int nid,
4506                                         unsigned long zone_type,
4507                                         unsigned long node_start_pfn,
4508                                         unsigned long node_end_pfn,
4509                                         unsigned long *zone_start_pfn,
4510                                         unsigned long *zone_end_pfn)
4511 {
4512         /* Only adjust if ZONE_MOVABLE is on this node */
4513         if (zone_movable_pfn[nid]) {
4514                 /* Size ZONE_MOVABLE */
4515                 if (zone_type == ZONE_MOVABLE) {
4516                         *zone_start_pfn = zone_movable_pfn[nid];
4517                         *zone_end_pfn = min(node_end_pfn,
4518                                 arch_zone_highest_possible_pfn[movable_zone]);
4519 
4520                 /* Adjust for ZONE_MOVABLE starting within this range */
4521                 } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
4522                                 *zone_end_pfn > zone_movable_pfn[nid]) {
4523                         *zone_end_pfn = zone_movable_pfn[nid];
4524 
4525                 /* Check if this whole range is within ZONE_MOVABLE */
4526                 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
4527                         *zone_start_pfn = *zone_end_pfn;
4528         }
4529 }
4530 
4531 /*
4532  * Return the number of pages a zone spans in a node, including holes
4533  * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
4534  */
4535 static unsigned long __meminit zone_spanned_pages_in_node(int nid,
4536                                         unsigned long zone_type,
4537                                         unsigned long node_start_pfn,
4538                                         unsigned long node_end_pfn,
4539                                         unsigned long *ignored)
4540 {
4541         unsigned long zone_start_pfn, zone_end_pfn;
4542 
4543         /* Get the start and end of the zone */
4544         zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
4545         zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
4546         adjust_zone_range_for_zone_movable(nid, zone_type,
4547                                 node_start_pfn, node_end_pfn,
4548                                 &zone_start_pfn, &zone_end_pfn);
4549 
4550         /* Check that this node has pages within the zone's required range */
4551         if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
4552                 return 0;
4553 
4554         /* Move the zone boundaries inside the node if necessary */
4555         zone_end_pfn = min(zone_end_pfn, node_end_pfn);
4556         zone_start_pfn = max(zone_start_pfn, node_start_pfn);
4557 
4558         /* Return the spanned pages */
4559         return zone_end_pfn - zone_start_pfn;
4560 }
4561 
4562 /*
4563  * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
4564  * then all holes in the requested range will be accounted for.
4565  */
4566 unsigned long __meminit __absent_pages_in_range(int nid,
4567                                 unsigned long range_start_pfn,
4568                                 unsigned long range_end_pfn)
4569 {
4570         unsigned long nr_absent = range_end_pfn - range_start_pfn;
4571         unsigned long start_pfn, end_pfn;
4572         int i;
4573 
4574         for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
4575                 start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
4576                 end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
4577                 nr_absent -= end_pfn - start_pfn;
4578         }
4579         return nr_absent;
4580 }
4581 
4582 /**
4583  * absent_pages_in_range - Return number of page frames in holes within a range
4584  * @start_pfn: The start PFN to start searching for holes
4585  * @end_pfn: The end PFN to stop searching for holes
4586  *
4587  * It returns the number of pages frames in memory holes within a range.
4588  */
4589 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
4590                                                         unsigned long end_pfn)
4591 {
4592         return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
4593 }
4594 
4595 /* Return the number of page frames in holes in a zone on a node */
4596 static unsigned long __meminit zone_absent_pages_in_node(int nid,
4597                                         unsigned long zone_type,
4598                                         unsigned long node_start_pfn,
4599                                         unsigned long node_end_pfn,
4600                                         unsigned long *ignored)
4601 {
4602         unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
4603         unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
4604         unsigned long zone_start_pfn, zone_end_pfn;
4605 
4606         zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
4607         zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
4608 
4609         adjust_zone_range_for_zone_movable(nid, zone_type,
4610                         node_start_pfn, node_end_pfn,
4611                         &zone_start_pfn, &zone_end_pfn);
4612         return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
4613 }
4614 
4615 #else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4616 static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
4617                                         unsigned long zone_type,
4618                                         unsigned long node_start_pfn,
4619                                         unsigned long node_end_pfn,
4620                                         unsigned long *zones_size)
4621 {
4622         return zones_size[zone_type];
4623 }
4624 
4625 static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
4626                                                 unsigned long zone_type,
4627                                                 unsigned long node_start_pfn,
4628                                                 unsigned long node_end_pfn,
4629                                                 unsigned long *zholes_size)
4630 {
4631         if (!zholes_size)
4632                 return 0;
4633 
4634         return zholes_size[zone_type];
4635 }
4636 
4637 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4638 
4639 static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
4640                                                 unsigned long node_start_pfn,
4641                                                 unsigned long node_end_pfn,
4642                                                 unsigned long *zones_size,
4643                                                 unsigned long *zholes_size)
4644 {
4645         unsigned long realtotalpages, totalpages = 0;
4646         enum zone_type i;
4647 
4648         for (i = 0; i < MAX_NR_ZONES; i++)
4649                 totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
4650                                                          node_start_pfn,
4651                                                          node_end_pfn,
4652                                                          zones_size);
4653         pgdat->node_spanned_pages = totalpages;
4654 
4655         realtotalpages = totalpages;
4656         for (i = 0; i < MAX_NR_ZONES; i++)
4657                 realtotalpages -=
4658                         zone_absent_pages_in_node(pgdat->node_id, i,
4659                                                   node_start_pfn, node_end_pfn,
4660                                                   zholes_size);
4661         pgdat->node_present_pages = realtotalpages;
4662         printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
4663                                                         realtotalpages);
4664 }
4665 
4666 #ifndef CONFIG_SPARSEMEM
4667 /*
4668  * Calculate the size of the zone->blockflags rounded to an unsigned long
4669  * Start by making sure zonesize is a multiple of pageblock_order by rounding
4670  * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
4671  * round what is now in bits to nearest long in bits, then return it in
4672  * bytes.
4673  */
4674 static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
4675 {
4676         unsigned long usemapsize;
4677 
4678         zonesize += zone_start_pfn & (pageblock_nr_pages-1);
4679         usemapsize = roundup(zonesize, pageblock_nr_pages);
4680         usemapsize = usemapsize >> pageblock_order;
4681         usemapsize *= NR_PAGEBLOCK_BITS;
4682         usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
4683 
4684         return usemapsize / 8;
4685 }
4686 
4687 static void __init setup_usemap(struct pglist_data *pgdat,
4688                                 struct zone *zone,
4689                                 unsigned long zone_start_pfn,
4690                                 unsigned long zonesize)
4691 {
4692         unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
4693         zone->pageblock_flags = NULL;
4694         if (usemapsize)
4695                 zone->pageblock_flags =
4696                         memblock_virt_alloc_node_nopanic(usemapsize,
4697                                                          pgdat->node_id);
4698 }
4699 #else
4700 static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
4701                                 unsigned long zone_start_pfn, unsigned long zonesize) {}
4702 #endif /* CONFIG_SPARSEMEM */
4703 
4704 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
4705 
4706 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
4707 void __paginginit set_pageblock_order(void)
4708 {
4709         unsigned int order;
4710 
4711         /* Check that pageblock_nr_pages has not already been setup */
4712         if (pageblock_order)
4713                 return;
4714 
4715         if (HPAGE_SHIFT > PAGE_SHIFT)
4716                 order = HUGETLB_PAGE_ORDER;
4717         else
4718                 order = MAX_ORDER - 1;
4719 
4720         /*
4721          * Assume the largest contiguous order of interest is a huge page.
4722          * This value may be variable depending on boot parameters on IA64 and
4723          * powerpc.
4724          */
4725         pageblock_order = order;
4726 }
4727 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4728 
4729 /*
4730  * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
4731  * is unused as pageblock_order is set at compile-time. See
4732  * include/linux/pageblock-flags.h for the values of pageblock_order based on
4733  * the kernel config
4734  */
4735 void __paginginit set_pageblock_order(void)
4736 {
4737 }
4738 
4739 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4740 
4741 static unsigned long __paginginit calc_memmap_size(unsigned long spanned_pages,
4742                                                    unsigned long present_pages)
4743 {
4744         unsigned long pages = spanned_pages;
4745 
4746         /*
4747          * Provide a more accurate estimation if there are holes within
4748          * the zone and SPARSEMEM is in use. If there are holes within the
4749          * zone, each populated memory region may cost us one or two extra
4750          * memmap pages due to alignment because memmap pages for each
4751          * populated regions may not naturally algined on page boundary.
4752          * So the (present_pages >> 4) heuristic is a tradeoff for that.
4753          */
4754         if (spanned_pages > present_pages + (present_pages >> 4) &&
4755             IS_ENABLED(CONFIG_SPARSEMEM))
4756                 pages = present_pages;
4757 
4758         return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
4759 }
4760 
4761 /*
4762  * Set up the zone data structures:
4763  *   - mark all pages reserved
4764  *   - mark all memory queues empty
4765  *   - clear the memory bitmaps
4766  *
4767  * NOTE: pgdat should get zeroed by caller.
4768  */
4769 static void __paginginit free_area_init_core(struct pglist_data *pgdat,
4770                 unsigned long node_start_pfn, unsigned long node_end_pfn,
4771                 unsigned long *zones_size, unsigned long *zholes_size)
4772 {
4773         enum zone_type j;
4774         int nid = pgdat->node_id;
4775         unsigned long zone_start_pfn = pgdat->node_start_pfn;
4776         int ret;
4777 
4778         pgdat_resize_init(pgdat);
4779 #ifdef CONFIG_NUMA_BALANCING
4780         spin_lock_init(&pgdat->numabalancing_migrate_lock);
4781         pgdat->numabalancing_migrate_nr_pages = 0;
4782         pgdat->numabalancing_migrate_next_window = jiffies;
4783 #endif
4784         init_waitqueue_head(&pgdat->kswapd_wait);
4785         init_waitqueue_head(&pgdat->pfmemalloc_wait);
4786         pgdat_page_cgroup_init(pgdat);
4787 
4788         for (j = 0; j < MAX_NR_ZONES; j++) {
4789                 struct zone *zone = pgdat->node_zones + j;
4790                 unsigned long size, realsize, freesize, memmap_pages;
4791 
4792                 size = zone_spanned_pages_in_node(nid, j, node_start_pfn,
4793                                                   node_end_pfn, zones_size);
4794                 realsize = freesize = size - zone_absent_pages_in_node(nid, j,
4795                                                                 node_start_pfn,
4796                                                                 node_end_pfn,
4797                                                                 zholes_size);
4798 
4799                 /*
4800                  * Adjust freesize so that it accounts for how much memory
4801                  * is used by this zone for memmap. This affects the watermark
4802                  * and per-cpu initialisations
4803                  */
4804                 memmap_pages = calc_memmap_size(size, realsize);
4805                 if (freesize >= memmap_pages) {
4806                         freesize -= memmap_pages;
4807                         if (memmap_pages)
4808                                 printk(KERN_DEBUG
4809                                        "  %s zone: %lu pages used for memmap\n",
4810                                        zone_names[j], memmap_pages);
4811                 } else
4812                         printk(KERN_WARNING
4813                                 "  %s zone: %lu pages exceeds freesize %lu\n",
4814                                 zone_names[j], memmap_pages, freesize);
4815 
4816                 /* Account for reserved pages */
4817                 if (j == 0 && freesize > dma_reserve) {
4818                         freesize -= dma_reserve;
4819                         printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
4820                                         zone_names[0], dma_reserve);
4821                 }
4822 
4823                 if (!is_highmem_idx(j))
4824                         nr_kernel_pages += freesize;
4825                 /* Charge for highmem memmap if there are enough kernel pages */
4826                 else if (nr_kernel_pages > memmap_pages * 2)
4827                         nr_kernel_pages -= memmap_pages;
4828                 nr_all_pages += freesize;
4829 
4830                 zone->spanned_pages = size;
4831                 zone->present_pages = realsize;
4832                 /*
4833                  * Set an approximate value for lowmem here, it will be adjusted
4834                  * when the bootmem allocator frees pages into the buddy system.
4835                  * And all highmem pages will be managed by the buddy system.
4836                  */
4837                 zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
4838 #ifdef CONFIG_NUMA
4839                 zone->node = nid;
4840                 zone->min_unmapped_pages = (freesize*sysctl_min_unmapped_ratio)
4841                                                 / 100;
4842                 zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100;
4843 #endif
4844                 zone->name = zone_names[j];
4845                 spin_lock_init(&zone->lock);
4846                 spin_lock_init(&zone->lru_lock);
4847                 zone_seqlock_init(zone);
4848                 zone->zone_pgdat = pgdat;
4849                 zone_pcp_init(zone);
4850 
4851                 /* For bootup, initialized properly in watermark setup */
4852                 mod_zone_page_state(zone, NR_ALLOC_BATCH, zone->managed_pages);
4853 
4854                 lruvec_init(&zone->lruvec);
4855                 if (!size)
4856                         continue;
4857 
4858                 set_pageblock_order();
4859                 setup_usemap(pgdat, zone, zone_start_pfn, size);
4860                 ret = init_currently_empty_zone(zone, zone_start_pfn,
4861                                                 size, MEMMAP_EARLY);
4862                 BUG_ON(ret);
4863                 memmap_init(size, nid, j, zone_start_pfn);
4864                 zone_start_pfn += size;
4865         }
4866 }
4867 
4868 static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
4869 {
4870         /* Skip empty nodes */
4871         if (!pgdat->node_spanned_pages)
4872                 return;
4873 
4874 #ifdef CONFIG_FLAT_NODE_MEM_MAP
4875         /* ia64 gets its own node_mem_map, before this, without bootmem */
4876         if (!pgdat->node_mem_map) {
4877                 unsigned long size, start, end;
4878                 struct page *map;
4879 
4880                 /*
4881                  * The zone's endpoints aren't required to be MAX_ORDER
4882                  * aligned but the node_mem_map endpoints must be in order
4883                  * for the buddy allocator to function correctly.
4884                  */
4885                 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
4886                 end = pgdat_end_pfn(pgdat);
4887                 end = ALIGN(end, MAX_ORDER_NR_PAGES);
4888                 size =  (end - start) * sizeof(struct page);
4889                 map = alloc_remap(pgdat->node_id, size);
4890                 if (!map)
4891                         map = memblock_virt_alloc_node_nopanic(size,
4892                                                                pgdat->node_id);
4893                 pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
4894         }
4895 #ifndef CONFIG_NEED_MULTIPLE_NODES
4896         /*
4897          * With no DISCONTIG, the global mem_map is just set as node 0's
4898          */
4899         if (pgdat == NODE_DATA(0)) {
4900                 mem_map = NODE_DATA(0)->node_mem_map;
4901 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4902                 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
4903                         mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
4904 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
4905         }
4906 #endif
4907 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
4908 }
4909 
4910 void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
4911                 unsigned long node_start_pfn, unsigned long *zholes_size)
4912 {
4913         pg_data_t *pgdat = NODE_DATA(nid);
4914         unsigned long start_pfn = 0;
4915         unsigned long end_pfn = 0;
4916 
4917         /* pg_data_t should be reset to zero when it's allocated */
4918         WARN_ON(pgdat->nr_zones || pgdat->classzone_idx);
4919 
4920         pgdat->node_id = nid;
4921         pgdat->node_start_pfn = node_start_pfn;
4922         init_zone_allows_reclaim(nid);
4923 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4924         get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
4925 #endif
4926         calculate_node_totalpages(pgdat, start_pfn, end_pfn,
4927                                   zones_size, zholes_size);
4928 
4929         alloc_node_mem_map(pgdat);
4930 #ifdef CONFIG_FLAT_NODE_MEM_MAP
4931         printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
4932                 nid, (unsigned long)pgdat,
4933                 (unsigned long)pgdat->node_mem_map);
4934 #endif
4935 
4936         free_area_init_core(pgdat, start_pfn, end_pfn,
4937                             zones_size, zholes_size);
4938 }
4939 
4940 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
4941 
4942 #if MAX_NUMNODES > 1
4943 /*
4944  * Figure out the number of possible node ids.
4945  */
4946 void __init setup_nr_node_ids(void)
4947 {
4948         unsigned int node;
4949         unsigned int highest = 0;
4950 
4951         for_each_node_mask(node, node_possible_map)
4952                 highest = node;
4953         nr_node_ids = highest + 1;
4954 }
4955 #endif
4956 
4957 /**
4958  * node_map_pfn_alignment - determine the maximum internode alignment
4959  *
4960  * This function should be called after node map is populated and sorted.
4961  * It calculates the maximum power of two alignment which can distinguish
4962  * all the nodes.
4963  *
4964  * For example, if all nodes are 1GiB and aligned to 1GiB, the return value
4965  * would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)).  If the
4966  * nodes are shifted by 256MiB, 256MiB.  Note that if only the last node is
4967  * shifted, 1GiB is enough and this function will indicate so.
4968  *
4969  * This is used to test whether pfn -> nid mapping of the chosen memory
4970  * model has fine enough granularity to avoid incorrect mapping for the
4971  * populated node map.
4972  *
4973  * Returns the determined alignment in pfn's.  0 if there is no alignment
4974  * requirement (single node).
4975  */
4976 unsigned long __init node_map_pfn_alignment(void)
4977 {
4978         unsigned long accl_mask = 0, last_end = 0;
4979         unsigned long start, end, mask;
4980         int last_nid = -1;
4981         int i, nid;
4982 
4983         for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
4984                 if (!start || last_nid < 0 || last_nid == nid) {
4985                         last_nid = nid;
4986                         last_end = end;
4987                         continue;
4988                 }
4989 
4990                 /*
4991                  * Start with a mask granular enough to pin-point to the
4992                  * start pfn and tick off bits one-by-one until it becomes
4993                  * too coarse to separate the current node from the last.
4994                  */
4995                 mask = ~((1 << __ffs(start)) - 1);
4996                 while (mask && last_end <= (start & (mask << 1)))
4997                         mask <<= 1;
4998 
4999                 /* accumulate all internode masks */
5000                 accl_mask |= mask;
5001         }
5002 
5003         /* convert mask to number of pages */
5004         return ~accl_mask + 1;
5005 }
5006 
5007 /* Find the lowest pfn for a node */
5008 static unsigned long __init find_min_pfn_for_node(int nid)
5009 {
5010         unsigned long min_pfn = ULONG_MAX;
5011         unsigned long start_pfn;
5012         int i;
5013 
5014         for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
5015                 min_pfn = min(min_pfn, start_pfn);
5016 
5017         if (min_pfn == ULONG_MAX) {
5018                 printk(KERN_WARNING
5019                         "Could not find start_pfn for node %d\n", nid);
5020                 return 0;
5021         }
5022 
5023         return min_pfn;
5024 }
5025 
5026 /**
5027  * find_min_pfn_with_active_regions - Find the minimum PFN registered
5028  *
5029  * It returns the minimum PFN based on information provided via
5030  * add_active_range().
5031  */
5032 unsigned long __init find_min_pfn_with_active_regions(void)
5033 {
5034         return find_min_pfn_for_node(MAX_NUMNODES);
5035 }
5036 
5037 /*
5038  * early_calculate_totalpages()
5039  * Sum pages in active regions for movable zone.
5040  * Populate N_MEMORY for calculating usable_nodes.
5041  */
5042 static unsigned long __init early_calculate_totalpages(void)
5043 {
5044         unsigned long totalpages = 0;
5045         unsigned long start_pfn, end_pfn;
5046         int i, nid;
5047 
5048         for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
5049                 unsigned long pages = end_pfn - start_pfn;
5050 
5051                 totalpages += pages;
5052                 if (pages)
5053                         node_set_state(nid, N_MEMORY);
5054         }
5055         return totalpages;
5056 }
5057 
5058 /*
5059  * Find the PFN the Movable zone begins in each node. Kernel memory
5060  * is spread evenly between nodes as long as the nodes have enough
5061  * memory. When they don't, some nodes will have more kernelcore than
5062  * others
5063  */
5064 static void __init find_zone_movable_pfns_for_nodes(void)
5065 {
5066         int i, nid;
5067         unsigned long usable_startpfn;
5068         unsigned long kernelcore_node, kernelcore_remaining;
5069         /* save the state before borrow the nodemask */
5070         nodemask_t saved_node_state = node_states[N_MEMORY];
5071         unsigned long totalpages = early_calculate_totalpages();
5072         int usable_nodes = nodes_weight(node_states[N_MEMORY]);
5073         struct memblock_type *type = &memblock.memory;
5074 
5075         /* Need to find movable_zone earlier when movable_node is specified. */
5076         find_usable_zone_for_movable();
5077 
5078         /*
5079          * If movable_node is specified, ignore kernelcore and movablecore
5080          * options.
5081          */
5082         if (movable_node_is_enabled()) {
5083                 for (i = 0; i < type->cnt; i++) {
5084                         if (!memblock_is_hotpluggable(&type->regions[i]))
5085                                 continue;
5086 
5087                         nid = type->regions[i].nid;
5088 
5089                         usable_startpfn = PFN_DOWN(type->regions[i].base);
5090                         zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
5091                                 min(usable_startpfn, zone_movable_pfn[nid]) :
5092                                 usable_startpfn;
5093                 }
5094 
5095                 goto out2;
5096         }
5097 
5098         /*
5099          * If movablecore=nn[KMG] was specified, calculate what size of
5100          * kernelcore that corresponds so that memory usable for
5101          * any allocation type is evenly spread. If both kernelcore
5102          * and movablecore are specified, then the value of kernelcore
5103          * will be used for required_kernelcore if it's greater than
5104          * what movablecore would have allowed.
5105          */
5106         if (required_movablecore) {
5107                 unsigned long corepages;
5108 
5109                 /*
5110                  * Round-up so that ZONE_MOVABLE is at least as large as what
5111                  * was requested by the user
5112                  */
5113                 required_movablecore =
5114                         roundup(required_movablecore, MAX_ORDER_NR_PAGES);
5115                 corepages = totalpages - required_movablecore;
5116 
5117                 required_kernelcore = max(required_kernelcore, corepages);
5118         }
5119 
5120         /* If kernelcore was not specified, there is no ZONE_MOVABLE */
5121         if (!required_kernelcore)
5122                 goto out;
5123 
5124         /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
5125         usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
5126 
5127 restart:
5128         /* Spread kernelcore memory as evenly as possible throughout nodes */
5129         kernelcore_node = required_kernelcore / usable_nodes;
5130         for_each_node_state(nid, N_MEMORY) {
5131                 unsigned long start_pfn, end_pfn;
5132 
5133                 /*
5134                  * Recalculate kernelcore_node if the division per node
5135                  * now exceeds what is necessary to satisfy the requested
5136                  * amount of memory for the kernel
5137                  */
5138                 if (required_kernelcore < kernelcore_node)
5139                         kernelcore_node = required_kernelcore / usable_nodes;
5140 
5141                 /*
5142                  * As the map is walked, we track how much memory is usable
5143                  * by the kernel using kernelcore_remaining. When it is
5144                  * 0, the rest of the node is usable by ZONE_MOVABLE
5145                  */
5146                 kernelcore_remaining = kernelcore_node;
5147 
5148                 /* Go through each range of PFNs within this node */
5149                 for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
5150                         unsigned long size_pages;
5151 
5152                         start_pfn = max(start_pfn, zone_movable_pfn[nid]);
5153                         if (start_pfn >= end_pfn)
5154                                 continue;
5155 
5156                         /* Account for what is only usable for kernelcore */
5157                         if (start_pfn < usable_startpfn) {
5158                                 unsigned long kernel_pages;
5159                                 kernel_pages = min(end_pfn, usable_startpfn)
5160                                                                 - start_pfn;
5161 
5162                                 kernelcore_remaining -= min(kernel_pages,
5163                                                         kernelcore_remaining);
5164                                 required_kernelcore -= min(kernel_pages,
5165                                                         required_kernelcore);
5166 
5167                                 /* Continue if range is now fully accounted */
5168                                 if (end_pfn <= usable_startpfn) {
5169 
5170                                         /*
5171                                          * Push zone_movable_pfn to the end so
5172                                          * that if we have to rebalance
5173                                          * kernelcore across nodes, we will
5174                                          * not double account here
5175                                          */
5176                                         zone_movable_pfn[nid] = end_pfn;
5177                                         continue;
5178                                 }
5179                                 start_pfn = usable_startpfn;
5180                         }
5181 
5182                         /*
5183                          * The usable PFN range for ZONE_MOVABLE is from
5184                          * start_pfn->end_pfn. Calculate size_pages as the
5185                          * number of pages used as kernelcore
5186                          */
5187                         size_pages = end_pfn - start_pfn;
5188                         if (size_pages > kernelcore_remaining)
5189                                 size_pages = kernelcore_remaining;
5190                         zone_movable_pfn[nid] = start_pfn + size_pages;
5191 
5192                         /*
5193                          * Some kernelcore has been met, update counts and
5194                          * break if the kernelcore for this node has been
5195                          * satisfied
5196                          */
5197                         required_kernelcore -= min(required_kernelcore,
5198                                                                 size_pages);
5199                         kernelcore_remaining -= size_pages;
5200                         if (!kernelcore_remaining)
5201                                 break;
5202                 }
5203         }
5204 
5205         /*
5206          * If there is still required_kernelcore, we do another pass with one
5207          * less node in the count. This will push zone_movable_pfn[nid] further
5208          * along on the nodes that still have memory until kernelcore is
5209          * satisfied
5210          */
5211         usable_nodes--;
5212         if (usable_nodes && required_kernelcore > usable_nodes)
5213                 goto restart;
5214 
5215 out2:
5216         /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
5217         for (nid = 0; nid < MAX_NUMNODES; nid++)
5218                 zone_movable_pfn[nid] =
5219                         roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
5220 
5221 out:
5222         /* restore the node_state */
5223         node_states[N_MEMORY] = saved_node_state;
5224 }
5225 
5226 /* Any regular or high memory on that node ? */
5227 static void check_for_memory(pg_data_t *pgdat, int nid)
5228 {
5229         enum zone_type zone_type;
5230 
5231         if (N_MEMORY == N_NORMAL_MEMORY)
5232                 return;
5233 
5234         for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
5235                 struct zone *zone = &pgdat->node_zones[zone_type];
5236                 if (populated_zone(zone)) {
5237                         node_set_state(nid, N_HIGH_MEMORY);
5238                         if (N_NORMAL_MEMORY != N_HIGH_MEMORY &&
5239                             zone_type <= ZONE_NORMAL)
5240                                 node_set_state(nid, N_NORMAL_MEMORY);
5241                         break;
5242                 }
5243         }
5244 }
5245 
5246 /**
5247  * free_area_init_nodes - Initialise all pg_data_t and zone data
5248  * @max_zone_pfn: an array of max PFNs for each zone
5249  *
5250  * This will call free_area_init_node() for each active node in the system.
5251  * Using the page ranges provided by add_active_range(), the size of each
5252  * zone in each node and their holes is calculated. If the maximum PFN
5253  * between two adjacent zones match, it is assumed that the zone is empty.
5254  * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
5255  * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
5256  * starts where the previous one ended. For example, ZONE_DMA32 starts
5257  * at arch_max_dma_pfn.
5258  */
5259 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
5260 {
5261         unsigned long start_pfn, end_pfn;
5262         int i, nid;
5263 
5264         /* Record where the zone boundaries are */
5265         memset(arch_zone_lowest_possible_pfn, 0,
5266                                 sizeof(arch_zone_lowest_possible_pfn));
5267         memset(arch_zone_highest_possible_pfn, 0,
5268                                 sizeof(arch_zone_highest_possible_pfn));
5269         arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
5270         arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
5271         for (i = 1; i < MAX_NR_ZONES; i++) {
5272                 if (i == ZONE_MOVABLE)
5273                         continue;
5274                 arch_zone_lowest_possible_pfn[i] =
5275                         arch_zone_highest_possible_pfn[i-1];
5276                 arch_zone_highest_possible_pfn[i] =
5277                         max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
5278         }
5279         arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
5280         arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
5281 
5282         /* Find the PFNs that ZONE_MOVABLE begins at in each node */
5283         memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
5284         find_zone_movable_pfns_for_nodes();
5285 
5286         /* Print out the zone ranges */
5287         printk("Zone ranges:\n");
5288         for (i = 0; i < MAX_NR_ZONES; i++) {
5289                 if (i == ZONE_MOVABLE)
5290                         continue;
5291                 printk(KERN_CONT "  %-8s ", zone_names[i]);
5292                 if (arch_zone_lowest_possible_pfn[i] ==
5293                                 arch_zone_highest_possible_pfn[i])
5294                         printk(KERN_CONT "empty\n");
5295                 else
5296                         printk(KERN_CONT "[mem %0#10lx-%0#10lx]\n",
5297                                 arch_zone_lowest_possible_pfn[i] << PAGE_SHIFT,
5298                                 (arch_zone_highest_possible_pfn[i]
5299                                         << PAGE_SHIFT) - 1);
5300         }
5301 
5302         /* Print out the PFNs ZONE_MOVABLE begins at in each node */
5303         printk("Movable zone start for each node\n");
5304         for (i = 0; i < MAX_NUMNODES; i++) {
5305                 if (zone_movable_pfn[i])
5306                         printk("  Node %d: %#010lx\n", i,
5307                                zone_movable_pfn[i] << PAGE_SHIFT);
5308         }
5309 
5310         /* Print out the early node map */
5311         printk("Early memory node ranges\n");
5312         for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
5313                 printk("  node %3d: [mem %#010lx-%#010lx]\n", nid,
5314                        start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1);
5315 
5316         /* Initialise every node */
5317         mminit_verify_pageflags_layout();
5318         setup_nr_node_ids();
5319         for_each_online_node(nid) {
5320                 pg_data_t *pgdat = NODE_DATA(nid);
5321                 free_area_init_node(nid, NULL,
5322                                 find_min_pfn_for_node(nid), NULL);
5323 
5324                 /* Any memory on that node */
5325                 if (pgdat->node_present_pages)
5326                         node_set_state(nid, N_MEMORY);
5327                 check_for_memory(pgdat, nid);
5328         }
5329 }
5330 
5331 static int __init cmdline_parse_core(char *p, unsigned long *core)
5332 {
5333         unsigned long long coremem;
5334         if (!p)
5335                 return -EINVAL;
5336 
5337         coremem = memparse(p, &p);
5338         *core = coremem >> PAGE_SHIFT;
5339 
5340         /* Paranoid check that UL is enough for the coremem value */
5341         WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
5342 
5343         return 0;
5344 }
5345 
5346 /*
5347  * kernelcore=size sets the amount of memory for use for allocations that
5348  * cannot be reclaimed or migrated.
5349  */
5350 static int __init cmdline_parse_kernelcore(char *p)
5351 {
5352         return cmdline_parse_core(p, &required_kernelcore);
5353 }
5354 
5355 /*
5356  * movablecore=size sets the amount of memory for use for allocations that
5357  * can be reclaimed or migrated.
5358  */
5359 static int __init cmdline_parse_movablecore(char *p)
5360 {
5361         return cmdline_parse_core(p, &required_movablecore);
5362 }
5363 
5364 early_param("kernelcore", cmdline_parse_kernelcore);
5365 early_param("movablecore", cmdline_parse_movablecore);
5366 
5367 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
5368 
5369 void adjust_managed_page_count(struct page *page, long count)
5370 {
5371         spin_lock(&managed_page_count_lock);
5372         page_zone(page)->managed_pages += count;
5373         totalram_pages += count;
5374 #ifdef CONFIG_HIGHMEM
5375         if (PageHighMem(page))
5376                 totalhigh_pages += count;
5377 #endif
5378         spin_unlock(&managed_page_count_lock);
5379 }
5380 EXPORT_SYMBOL(adjust_managed_page_count);
5381 
5382 unsigned long free_reserved_area(void *start, void *end, int poison, char *s)
5383 {
5384         void *pos;
5385         unsigned long pages = 0;
5386 
5387         start = (void *)PAGE_ALIGN((unsigned long)start);
5388         end = (void *)((unsigned long)end & PAGE_MASK);
5389         for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
5390                 if ((unsigned int)poison <= 0xFF)
5391                         memset(pos, poison, PAGE_SIZE);
5392                 free_reserved_page(virt_to_page(pos));
5393         }
5394 
5395         if (pages && s)
5396                 pr_info("Freeing %s memory: %ldK (%p - %p)\n",
5397                         s, pages << (PAGE_SHIFT - 10), start, end);
5398 
5399         return pages;
5400 }
5401 EXPORT_SYMBOL(free_reserved_area);
5402 
5403 #ifdef  CONFIG_HIGHMEM
5404 void free_highmem_page(struct page *page)
5405 {
5406         __free_reserved_page(page);
5407         totalram_pages++;
5408         page_zone(page)->managed_pages++;
5409         totalhigh_pages++;
5410 }
5411 #endif
5412 
5413 
5414 void __init mem_init_print_info(const char *str)
5415 {
5416         unsigned long physpages, codesize, datasize, rosize, bss_size;
5417         unsigned long init_code_size, init_data_size;
5418 
5419         physpages = get_num_physpages();
5420         codesize = _etext - _stext;
5421         datasize = _edata - _sdata;
5422         rosize = __end_rodata - __start_rodata;
5423         bss_size = __bss_stop - __bss_start;
5424         init_data_size = __init_end - __init_begin;
5425         init_code_size = _einittext - _sinittext;
5426 
5427         /*
5428          * Detect special cases and adjust section sizes accordingly:
5429          * 1) .init.* may be embedded into .data sections
5430          * 2) .init.text.* may be out of [__init_begin, __init_end],
5431          *    please refer to arch/tile/kernel/vmlinux.lds.S.
5432          * 3) .rodata.* may be embedded into .text or .data sections.
5433          */
5434 #define adj_init_size(start, end, size, pos, adj) \
5435         do { \
5436                 if (start <= pos && pos < end && size > adj) \
5437                         size -= adj; \
5438         } while (0)
5439 
5440         adj_init_size(__init_begin, __init_end, init_data_size,
5441                      _sinittext, init_code_size);
5442         adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
5443         adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
5444         adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
5445         adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
5446 
5447 #undef  adj_init_size
5448 
5449         printk("Memory: %luK/%luK available "
5450                "(%luK kernel code, %luK rwdata, %luK rodata, "
5451                "%luK init, %luK bss, %luK reserved"
5452 #ifdef  CONFIG_HIGHMEM
5453                ", %luK highmem"
5454 #endif
5455                "%s%s)\n",
5456                nr_free_pages() << (PAGE_SHIFT-10), physpages << (PAGE_SHIFT-10),
5457                codesize >> 10, datasize >> 10, rosize >> 10,
5458                (init_data_size + init_code_size) >> 10, bss_size >> 10,
5459                (physpages - totalram_pages) << (PAGE_SHIFT-10),
5460 #ifdef  CONFIG_HIGHMEM
5461                totalhigh_pages << (PAGE_SHIFT-10),
5462 #endif
5463                str ? ", " : "", str ? str : "");
5464 }
5465 
5466 /**
5467  * set_dma_reserve - set the specified number of pages reserved in the first zone
5468  * @new_dma_reserve: The number of pages to mark reserved
5469  *
5470  * The per-cpu batchsize and zone watermarks are determined by present_pages.
5471  * In the DMA zone, a significant percentage may be consumed by kernel image
5472  * and other unfreeable allocations which can skew the watermarks badly. This
5473  * function may optionally be used to account for unfreeable pages in the
5474  * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
5475  * smaller per-cpu batchsize.
5476  */
5477 void __init set_dma_reserve(unsigned long new_dma_reserve)
5478 {
5479         dma_reserve = new_dma_reserve;
5480 }
5481 
5482 void __init free_area_init(unsigned long *zones_size)
5483 {
5484         free_area_init_node(0, zones_size,
5485                         __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
5486 }
5487 
5488 static int page_alloc_cpu_notify(struct notifier_block *self,
5489                                  unsigned long action, void *hcpu)
5490 {
5491         int cpu = (unsigned long)hcpu;
5492 
5493         if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
5494                 lru_add_drain_cpu(cpu);
5495                 drain_pages(cpu);
5496 
5497                 /*
5498                  * Spill the event counters of the dead processor
5499                  * into the current processors event counters.
5500                  * This artificially elevates the count of the current
5501                  * processor.
5502                  */
5503                 vm_events_fold_cpu(cpu);
5504 
5505                 /*
5506                  * Zero the differential counters of the dead processor
5507                  * so that the vm statistics are consistent.
5508                  *
5509                  * This is only okay since the processor is dead and cannot
5510                  * race with what we are doing.
5511                  */
5512                 cpu_vm_stats_fold(cpu);
5513         }
5514         return NOTIFY_OK;
5515 }
5516 
5517 void __init page_alloc_init(void)
5518 {
5519         hotcpu_notifier(page_alloc_cpu_notify, 0);
5520 }
5521 
5522 /*
5523  * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
5524  *      or min_free_kbytes changes.
5525  */
5526 static void calculate_totalreserve_pages(void)
5527 {
5528         struct pglist_data *pgdat;
5529         unsigned long reserve_pages = 0;
5530         enum zone_type i, j;
5531 
5532         for_each_online_pgdat(pgdat) {
5533                 for (i = 0; i < MAX_NR_ZONES; i++) {
5534                         struct zone *zone = pgdat->node_zones + i;
5535                         unsigned long max = 0;
5536 
5537                         /* Find valid and maximum lowmem_reserve in the zone */
5538                         for (j = i; j < MAX_NR_ZONES; j++) {
5539                                 if (zone->lowmem_reserve[j] > max)
5540                                         max = zone->lowmem_reserve[j];
5541                         }
5542 
5543                         /* we treat the high watermark as reserved pages. */
5544                         max += high_wmark_pages(zone);
5545 
5546                         if (max > zone->managed_pages)
5547                                 max = zone->managed_pages;
5548                         reserve_pages += max;
5549                         /*
5550                          * Lowmem reserves are not available to
5551                          * GFP_HIGHUSER page cache allocations and
5552                          * kswapd tries to balance zones to their high
5553                          * watermark.  As a result, neither should be
5554                          * regarded as dirtyable memory, to prevent a
5555                          * situation where reclaim has to clean pages
5556                          * in order to balance the zones.
5557                          */
5558                         zone->dirty_balance_reserve = max;
5559                 }
5560         }
5561         dirty_balance_reserve = reserve_pages;
5562         totalreserve_pages = reserve_pages;
5563 }
5564 
5565 /*
5566  * setup_per_zone_lowmem_reserve - called whenever
5567  *      sysctl_lower_zone_reserve_ratio changes.  Ensures that each zone
5568  *      has a correct pages reserved value, so an adequate number of
5569  *      pages are left in the zone after a successful __alloc_pages().
5570  */
5571 static void setup_per_zone_lowmem_reserve(void)
5572 {
5573         struct pglist_data *pgdat;
5574         enum zone_type j, idx;
5575 
5576         for_each_online_pgdat(pgdat) {
5577                 for (j = 0; j < MAX_NR_ZONES; j++) {
5578                         struct zone *zone = pgdat->node_zones + j;
5579                         unsigned long managed_pages = zone->managed_pages;
5580 
5581                         zone->lowmem_reserve[j] = 0;
5582 
5583                         idx = j;
5584                         while (idx) {
5585                                 struct zone *lower_zone;
5586 
5587                                 idx--;
5588 
5589                                 if (sysctl_lowmem_reserve_ratio[idx] < 1)
5590                                         sysctl_lowmem_reserve_ratio[idx] = 1;
5591 
5592                                 lower_zone = pgdat->node_zones + idx;
5593                                 lower_zone->lowmem_reserve[j] = managed_pages /
5594                                         sysctl_lowmem_reserve_ratio[idx];
5595                                 managed_pages += lower_zone->managed_pages;
5596                         }
5597                 }
5598         }
5599 
5600         /* update totalreserve_pages */
5601         calculate_totalreserve_pages();
5602 }
5603 
5604 static void __setup_per_zone_wmarks(void)
5605 {
5606         unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
5607         unsigned long lowmem_pages = 0;
5608         struct zone *zone;
5609         unsigned long flags;
5610 
5611         /* Calculate total number of !ZONE_HIGHMEM pages */
5612         for_each_zone(zone) {
5613                 if (!is_highmem(zone))
5614                         lowmem_pages += zone->managed_pages;
5615         }
5616 
5617         for_each_zone(zone) {
5618                 u64 tmp;
5619 
5620                 spin_lock_irqsave(&zone->lock, flags);
5621                 tmp = (u64)pages_min * zone->managed_pages;
5622                 do_div(tmp, lowmem_pages);
5623                 if (is_highmem(zone)) {
5624                         /*
5625                          * __GFP_HIGH and PF_MEMALLOC allocations usually don't
5626                          * need highmem pages, so cap pages_min to a small
5627                          * value here.
5628                          *
5629                          * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
5630                          * deltas controls asynch page reclaim, and so should
5631                          * not be capped for highmem.
5632                          */
5633                         unsigned long min_pages;
5634 
5635                         min_pages = zone->managed_pages / 1024;
5636                         min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
5637                         zone->watermark[WMARK_MIN] = min_pages;
5638                 } else {
5639                         /*
5640                          * If it's a lowmem zone, reserve a number of pages
5641                          * proportionate to the zone's size.
5642                          */
5643                         zone->watermark[WMARK_MIN] = tmp;
5644                 }
5645 
5646                 zone->watermark[WMARK_LOW]  = min_wmark_pages(zone) + (tmp >> 2);
5647                 zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
5648 
5649                 __mod_zone_page_state(zone, NR_ALLOC_BATCH,
5650                                       high_wmark_pages(zone) -
5651                                       low_wmark_pages(zone) -
5652                                       zone_page_state(zone, NR_ALLOC_BATCH));
5653 
5654                 setup_zone_migrate_reserve(zone);
5655                 spin_unlock_irqrestore(&zone->lock, flags);
5656         }
5657 
5658         /* update totalreserve_pages */
5659         calculate_totalreserve_pages();
5660 }
5661 
5662 /**
5663  * setup_per_zone_wmarks - called when min_free_kbytes changes
5664  * or when memory is hot-{added|removed}
5665  *
5666  * Ensures that the watermark[min,low,high] values for each zone are set
5667  * correctly with respect to min_free_kbytes.
5668  */
5669 void setup_per_zone_wmarks(void)
5670 {
5671         mutex_lock(&zonelists_mutex);
5672         __setup_per_zone_wmarks();
5673         mutex_unlock(&zonelists_mutex);
5674 }
5675 
5676 /*
5677  * The inactive anon list should be small enough that the VM never has to
5678  * do too much work, but large enough that each inactive page has a chance
5679  * to be referenced again before it is swapped out.
5680  *
5681  * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
5682  * INACTIVE_ANON pages on this zone's LRU, maintained by the
5683  * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
5684  * the anonymous pages are kept on the inactive list.
5685  *
5686  * total     target    max
5687  * memory    ratio     inactive anon
5688  * -------------------------------------
5689  *   10MB       1         5MB
5690  *  100MB       1        50MB
5691  *    1GB       3       250MB
5692  *   10GB      10       0.9GB
5693  *  100GB      31         3GB
5694  *    1TB     101        10GB
5695  *   10TB     320        32GB
5696  */
5697 static void __meminit calculate_zone_inactive_ratio(struct zone *zone)
5698 {
5699         unsigned int gb, ratio;
5700 
5701         /* Zone size in gigabytes */
5702         gb = zone->managed_pages >> (30 - PAGE_SHIFT);
5703         if (gb)
5704                 ratio = int_sqrt(10 * gb);
5705         else
5706                 ratio = 1;
5707 
5708         zone->inactive_ratio = ratio;
5709 }
5710 
5711 static void __meminit setup_per_zone_inactive_ratio(void)
5712 {
5713         struct zone *zone;
5714 
5715         for_each_zone(zone)
5716                 calculate_zone_inactive_ratio(zone);
5717 }
5718 
5719 /*
5720  * Initialise min_free_kbytes.
5721  *
5722  * For small machines we want it small (128k min).  For large machines
5723  * we want it large (64MB max).  But it is not linear, because network
5724  * bandwidth does not increase linearly with machine size.  We use
5725  *
5726  *      min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
5727  *      min_free_kbytes = sqrt(lowmem_kbytes * 16)
5728  *
5729  * which yields
5730  *
5731  * 16MB:        512k
5732  * 32MB:        724k
5733  * 64MB:        1024k
5734  * 128MB:       1448k
5735  * 256MB:       2048k
5736  * 512MB:       2896k
5737  * 1024MB:      4096k
5738  * 2048MB:      5792k
5739  * 4096MB:      8192k
5740  * 8192MB:      11584k
5741  * 16384MB:     16384k
5742  */
5743 int __meminit init_per_zone_wmark_min(void)
5744 {
5745         unsigned long lowmem_kbytes;
5746         int new_min_free_kbytes;
5747 
5748         lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
5749         new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
5750 
5751         if (new_min_free_kbytes > user_min_free_kbytes) {
5752                 min_free_kbytes = new_min_free_kbytes;
5753                 if (min_free_kbytes < 128)
5754                         min_free_kbytes = 128;
5755                 if (min_free_kbytes > 65536)
5756                         min_free_kbytes = 65536;
5757         } else {
5758                 pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
5759                                 new_min_free_kbytes, user_min_free_kbytes);
5760         }
5761         setup_per_zone_wmarks();
5762         refresh_zone_stat_thresholds();
5763         setup_per_zone_lowmem_reserve();
5764         setup_per_zone_inactive_ratio();
5765         return 0;
5766 }
5767 module_init(init_per_zone_wmark_min)
5768 
5769 /*
5770  * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so
5771  *      that we can call two helper functions whenever min_free_kbytes
5772  *      changes.
5773  */
5774 int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
5775         void __user *buffer, size_t *length, loff_t *ppos)
5776 {
5777         int rc;
5778 
5779         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5780         if (rc)
5781                 return rc;
5782 
5783         if (write) {
5784                 user_min_free_kbytes = min_free_kbytes;
5785                 setup_per_zone_wmarks();
5786         }
5787         return 0;
5788 }
5789 
5790 #ifdef CONFIG_NUMA
5791 int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
5792         void __user *buffer, size_t *length, loff_t *ppos)
5793 {
5794         struct zone *zone;
5795         int rc;
5796 
5797         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5798         if (rc)
5799                 return rc;
5800 
5801         for_each_zone(zone)
5802                 zone->min_unmapped_pages = (zone->managed_pages *
5803                                 sysctl_min_unmapped_ratio) / 100;
5804         return 0;
5805 }
5806 
5807 int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
5808         void __user *buffer, size_t *length, loff_t *ppos)
5809 {
5810         struct zone *zone;
5811         int rc;
5812 
5813         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5814         if (rc)
5815                 return rc;
5816 
5817         for_each_zone(zone)
5818                 zone->min_slab_pages = (zone->managed_pages *
5819                                 sysctl_min_slab_ratio) / 100;
5820         return 0;
5821 }
5822 #endif
5823 
5824 /*
5825  * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
5826  *      proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
5827  *      whenever sysctl_lowmem_reserve_ratio changes.
5828  *
5829  * The reserve ratio obviously has absolutely no relation with the
5830  * minimum watermarks. The lowmem reserve ratio can only make sense
5831  * if in function of the boot time zone sizes.
5832  */
5833 int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
5834         void __user *buffer, size_t *length, loff_t *ppos)
5835 {
5836         proc_dointvec_minmax(table, write, buffer, length, ppos);
5837         setup_per_zone_lowmem_reserve();
5838         return 0;
5839 }
5840 
5841 /*
5842  * percpu_pagelist_fraction - changes the pcp->high for each zone on each
5843  * cpu.  It is the fraction of total pages in each zone that a hot per cpu
5844  * pagelist can have before it gets flushed back to buddy allocator.
5845  */
5846 int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
5847         void __user *buffer, size_t *length, loff_t *ppos)
5848 {
5849         struct zone *zone;
5850         unsigned int cpu;
5851         int ret;
5852 
5853         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
5854         if (!write || (ret < 0))
5855                 return ret;
5856 
5857         mutex_lock(&pcp_batch_high_lock);
5858         for_each_populated_zone(zone) {
5859                 unsigned long  high;
5860                 high = zone->managed_pages / percpu_pagelist_fraction;
5861                 for_each_possible_cpu(cpu)
5862                         pageset_set_high(per_cpu_ptr(zone->pageset, cpu),
5863                                          high);
5864         }
5865         mutex_unlock(&pcp_batch_high_lock);
5866         return 0;
5867 }
5868 
5869 int hashdist = HASHDIST_DEFAULT;
5870 
5871 #ifdef CONFIG_NUMA
5872 static int __init set_hashdist(char *str)
5873 {
5874         if (!str)
5875                 return 0;
5876         hashdist = simple_strtoul(str, &str, 0);
5877         return 1;
5878 }
5879 __setup("hashdist=", set_hashdist);
5880 #endif
5881 
5882 /*
5883  * allocate a large system hash table from bootmem
5884  * - it is assumed that the hash table must contain an exact power-of-2
5885  *   quantity of entries
5886  * - limit is the number of hash buckets, not the total allocation size
5887  */
5888 void *__init alloc_large_system_hash(const char *tablename,
5889                                      unsigned long bucketsize,
5890                                      unsigned long numentries,
5891                                      int scale,
5892                                      int flags,
5893                                      unsigned int *_hash_shift,
5894                                      unsigned int *_hash_mask,
5895                                      unsigned long low_limit,
5896                                      unsigned long high_limit)
5897 {
5898         unsigned long long max = high_limit;
5899         unsigned long log2qty, size;
5900         void *table = NULL;
5901 
5902         /* allow the kernel cmdline to have a say */
5903         if (!numentries) {
5904                 /* round applicable memory size up to nearest megabyte */
5905                 numentries = nr_kernel_pages;
5906 
5907                 /* It isn't necessary when PAGE_SIZE >= 1MB */
5908                 if (PAGE_SHIFT < 20)
5909                         numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
5910 
5911                 /* limit to 1 bucket per 2^scale bytes of low memory */
5912                 if (scale > PAGE_SHIFT)
5913                         numentries >>= (scale - PAGE_SHIFT);
5914                 else
5915                         numentries <<= (PAGE_SHIFT - scale);
5916 
5917                 /* Make sure we've got at least a 0-order allocation.. */
5918                 if (unlikely(flags & HASH_SMALL)) {
5919                         /* Makes no sense without HASH_EARLY */
5920                         WARN_ON(!(flags & HASH_EARLY));
5921                         if (!(numentries >> *_hash_shift)) {
5922                                 numentries = 1UL << *_hash_shift;
5923                                 BUG_ON(!numentries);
5924                         }
5925                 } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
5926                         numentries = PAGE_SIZE / bucketsize;
5927         }
5928         numentries = roundup_pow_of_two(numentries);
5929 
5930         /* limit allocation size to 1/16 total memory by default */
5931         if (max == 0) {
5932                 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
5933                 do_div(max, bucketsize);
5934         }
5935         max = min(max, 0x80000000ULL);
5936 
5937         if (numentries < low_limit)
5938                 numentries = low_limit;
5939         if (numentries > max)
5940                 numentries = max;
5941 
5942         log2qty = ilog2(numentries);
5943 
5944         do {
5945                 size = bucketsize << log2qty;
5946                 if (flags & HASH_EARLY)
5947                         table = memblock_virt_alloc_nopanic(size, 0);
5948                 else if (hashdist)
5949                         table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
5950                 else {
5951                         /*
5952                          * If bucketsize is not a power-of-two, we may free
5953                          * some pages at the end of hash table which
5954                          * alloc_pages_exact() automatically does
5955                          */
5956                         if (get_order(size) < MAX_ORDER) {
5957                                 table = alloc_pages_exact(size, GFP_ATOMIC);
5958                                 kmemleak_alloc(table, size, 1, GFP_ATOMIC);
5959                         }
5960                 }
5961         } while (!table && size > PAGE_SIZE && --log2qty);
5962 
5963         if (!table)
5964                 panic("Failed to allocate %s hash table\n", tablename);
5965 
5966         printk(KERN_INFO "%s hash table entries: %ld (order: %d, %lu bytes)\n",
5967                tablename,
5968                (1UL << log2qty),
5969                ilog2(size) - PAGE_SHIFT,
5970                size);
5971 
5972         if (_hash_shift)
5973                 *_hash_shift = log2qty;
5974         if (_hash_mask)
5975                 *_hash_mask = (1 << log2qty) - 1;
5976 
5977         return table;
5978 }
5979 
5980 /* Return a pointer to the bitmap storing bits affecting a block of pages */
5981 static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
5982                                                         unsigned long pfn)
5983 {
5984 #ifdef CONFIG_SPARSEMEM
5985         return __pfn_to_section(pfn)->pageblock_flags;
5986 #else
5987         return zone->pageblock_flags;
5988 #endif /* CONFIG_SPARSEMEM */
5989 }
5990 
5991 static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
5992 {
5993 #ifdef CONFIG_SPARSEMEM
5994         pfn &= (PAGES_PER_SECTION-1);
5995         return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5996 #else
5997         pfn = pfn - round_down(zone->zone_start_pfn, pageblock_nr_pages);
5998         return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5999 #endif /* CONFIG_SPARSEMEM */
6000 }
6001 
6002 /**
6003  * get_pageblock_flags_group - Return the requested group of flags for the pageblock_nr_pages block of pages
6004  * @page: The page within the block of interest
6005  * @start_bitidx: The first bit of interest to retrieve
6006  * @end_bitidx: The last bit of interest
6007  * returns pageblock_bits flags
6008  */
6009 unsigned long get_pageblock_flags_group(struct page *page,
6010                                         int start_bitidx, int end_bitidx)
6011 {
6012         struct zone *zone;
6013         unsigned long *bitmap;
6014         unsigned long pfn, bitidx;
6015         unsigned long flags = 0;
6016         unsigned long value = 1;
6017 
6018         zone = page_zone(page);
6019         pfn = page_to_pfn(page);
6020         bitmap = get_pageblock_bitmap(zone, pfn);
6021         bitidx = pfn_to_bitidx(zone, pfn);
6022 
6023         for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
6024                 if (test_bit(bitidx + start_bitidx, bitmap))
6025                         flags |= value;
6026 
6027         return flags;
6028 }
6029 
6030 /**
6031  * set_pageblock_flags_group - Set the requested group of flags for a pageblock_nr_pages block of pages
6032  * @page: The page within the block of interest
6033  * @start_bitidx: The first bit of interest
6034  * @end_bitidx: The last bit of interest
6035  * @flags: The flags to set
6036  */
6037 void set_pageblock_flags_group(struct page *page, unsigned long flags,
6038                                         int start_bitidx, int end_bitidx)
6039 {
6040         struct zone *zone;
6041         unsigned long *bitmap;
6042         unsigned long pfn, bitidx;
6043         unsigned long value = 1;
6044 
6045         zone = page_zone(page);
6046         pfn = page_to_pfn(page);
6047         bitmap = get_pageblock_bitmap(zone, pfn);
6048         bitidx = pfn_to_bitidx(zone, pfn);
6049         VM_BUG_ON_PAGE(!zone_spans_pfn(zone, pfn), page);
6050 
6051         for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
6052                 if (flags & value)
6053                         __set_bit(bitidx + start_bitidx, bitmap);
6054                 else
6055                         __clear_bit(bitidx + start_bitidx, bitmap);
6056 }
6057 
6058 /*
6059  * This function checks whether pageblock includes unmovable pages or not.
6060  * If @count is not zero, it is okay to include less @count unmovable pages
6061  *
6062  * PageLRU check without isolation or lru_lock could race so that
6063  * MIGRATE_MOVABLE block might include unmovable pages. It means you can't
6064  * expect this function should be exact.
6065  */
6066 bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
6067                          bool skip_hwpoisoned_pages)
6068 {
6069         unsigned long pfn, iter, found;
6070         int mt;
6071 
6072         /*
6073          * For avoiding noise data, lru_add_drain_all() should be called
6074          * If ZONE_MOVABLE, the zone never contains unmovable pages
6075          */
6076         if (zone_idx(zone) == ZONE_MOVABLE)
6077                 return false;
6078         mt = get_pageblock_migratetype(page);
6079         if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
6080                 return false;
6081 
6082         pfn = page_to_pfn(page);
6083         for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
6084                 unsigned long check = pfn + iter;
6085 
6086                 if (!pfn_valid_within(check))
6087                         continue;
6088 
6089                 page = pfn_to_page(check);
6090 
6091                 /*
6092                  * Hugepages are not in LRU lists, but they're movable.
6093                  * We need not scan over tail pages bacause we don't
6094                  * handle each tail page individually in migration.
6095                  */
6096                 if (PageHuge(page)) {
6097                         iter = round_up(iter + 1, 1<<compound_order(page)) - 1;
6098                         continue;
6099                 }
6100 
6101                 /*
6102                  * We can't use page_count without pin a page
6103                  * because another CPU can free compound page.
6104                  * This check already skips compound tails of THP
6105                  * because their page->_count is zero at all time.
6106                  */
6107                 if (!atomic_read(&page->_count)) {
6108                         if (PageBuddy(page))
6109                                 iter += (1 << page_order(page)) - 1;
6110                         continue;
6111                 }
6112 
6113                 /*
6114                  * The HWPoisoned page may be not in buddy system, and
6115                  * page_count() is not 0.
6116                  */
6117                 if (skip_hwpoisoned_pages && PageHWPoison(page))
6118                         continue;
6119 
6120                 if (!PageLRU(page))
6121                         found++;
6122                 /*
6123                  * If there are RECLAIMABLE pages, we need to check it.
6124                  * But now, memory offline itself doesn't call shrink_slab()
6125                  * and it still to be fixed.
6126                  */
6127                 /*
6128                  * If the page is not RAM, page_count()should be 0.
6129                  * we don't need more check. This is an _used_ not-movable page.
6130                  *
6131                  * The problematic thing here is PG_reserved pages. PG_reserved
6132                  * is set to both of a memory hole page and a _used_ kernel
6133                  * page at boot.
6134                  */
6135                 if (found > count)
6136                         return true;
6137         }
6138         return false;
6139 }
6140 
6141 bool is_pageblock_removable_nolock(struct page *page)
6142 {
6143         struct zone *zone;
6144         unsigned long pfn;
6145 
6146         /*
6147          * We have to be careful here because we are iterating over memory
6148          * sections which are not zone aware so we might end up outside of
6149          * the zone but still within the section.
6150          * We have to take care about the node as well. If the node is offline
6151          * its NODE_DATA will be NULL - see page_zone.
6152          */
6153         if (!node_online(page_to_nid(page)))
6154                 return false;
6155 
6156         zone = page_zone(page);
6157         pfn = page_to_pfn(page);
6158         if (!zone_spans_pfn(zone, pfn))
6159                 return false;
6160 
6161         return !has_unmovable_pages(zone, page, 0, true);
6162 }
6163 
6164 #ifdef CONFIG_CMA
6165 
6166 static unsigned long pfn_max_align_down(unsigned long pfn)
6167 {
6168         return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
6169                              pageblock_nr_pages) - 1);
6170 }
6171 
6172 static unsigned long pfn_max_align_up(unsigned long pfn)
6173 {
6174         return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
6175                                 pageblock_nr_pages));
6176 }
6177 
6178 /* [start, end) must belong to a single zone. */
6179 static int __alloc_contig_migrate_range(struct compact_control *cc,
6180                                         unsigned long start, unsigned long end)
6181 {
6182         /* This function is based on compact_zone() from compaction.c. */
6183         unsigned long nr_reclaimed;
6184         unsigned long pfn = start;
6185         unsigned int tries = 0;
6186         int ret = 0;
6187 
6188         migrate_prep();
6189 
6190         while (pfn < end || !list_empty(&cc->migratepages)) {
6191                 if (fatal_signal_pending(current)) {
6192                         ret = -EINTR;
6193                         break;
6194                 }
6195 
6196                 if (list_empty(&cc->migratepages)) {
6197                         cc->nr_migratepages = 0;
6198                         pfn = isolate_migratepages_range(cc->zone, cc,
6199                                                          pfn, end, true);
6200                         if (!pfn) {
6201                                 ret = -EINTR;
6202                                 break;
6203                         }
6204                         tries = 0;
6205                 } else if (++tries == 5) {
6206                         ret = ret < 0 ? ret : -EBUSY;
6207                         break;
6208                 }
6209 
6210                 nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
6211                                                         &cc->migratepages);
6212                 cc->nr_migratepages -= nr_reclaimed;
6213 
6214                 ret = migrate_pages(&cc->migratepages, alloc_migrate_target,
6215                                     0, MIGRATE_SYNC, MR_CMA);
6216         }
6217         if (ret < 0) {
6218                 putback_movable_pages(&cc->migratepages);
6219                 return ret;
6220         }
6221         return 0;
6222 }
6223 
6224 /**
6225  * alloc_contig_range() -- tries to allocate given range of pages
6226  * @start:      start PFN to allocate
6227  * @end:        one-past-the-last PFN to allocate
6228  * @migratetype:        migratetype of the underlaying pageblocks (either
6229  *                      #MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
6230  *                      in range must have the same migratetype and it must
6231  *                      be either of the two.
6232  *
6233  * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
6234  * aligned, however it's the caller's responsibility to guarantee that
6235  * we are the only thread that changes migrate type of pageblocks the
6236  * pages fall in.
6237  *
6238  * The PFN range must belong to a single zone.
6239  *
6240  * Returns zero on success or negative error code.  On success all
6241  * pages which PFN is in [start, end) are allocated for the caller and
6242  * need to be freed with free_contig_range().
6243  */
6244 int alloc_contig_range(unsigned long start, unsigned long end,
6245                        unsigned migratetype)
6246 {
6247         unsigned long outer_start, outer_end;
6248         int ret = 0, order;
6249 
6250         struct compact_control cc = {
6251                 .nr_migratepages = 0,
6252                 .order = -1,
6253                 .zone = page_zone(pfn_to_page(start)),
6254                 .sync = true,
6255                 .ignore_skip_hint = true,
6256         };
6257         INIT_LIST_HEAD(&cc.migratepages);
6258 
6259         /*
6260          * What we do here is we mark all pageblocks in range as
6261          * MIGRATE_ISOLATE.  Because pageblock and max order pages may
6262          * have different sizes, and due to the way page allocator
6263          * work, we align the range to biggest of the two pages so
6264          * that page allocator won't try to merge buddies from
6265          * different pageblocks and change MIGRATE_ISOLATE to some
6266          * other migration type.
6267          *
6268          * Once the pageblocks are marked as MIGRATE_ISOLATE, we
6269          * migrate the pages from an unaligned range (ie. pages that
6270          * we are interested in).  This will put all the pages in
6271          * range back to page allocator as MIGRATE_ISOLATE.
6272          *
6273          * When this is done, we take the pages in range from page
6274          * allocator removing them from the buddy system.  This way
6275          * page allocator will never consider using them.
6276          *
6277          * This lets us mark the pageblocks back as
6278          * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
6279          * aligned range but not in the unaligned, original range are
6280          * put back to page allocator so that buddy can use them.
6281          */
6282 
6283         ret = start_isolate_page_range(pfn_max_align_down(start),
6284                                        pfn_max_align_up(end), migratetype,
6285                                        false);
6286         if (ret)
6287                 return ret;
6288 
6289         ret = __alloc_contig_migrate_range(&cc, start, end);
6290         if (ret)
6291                 goto done;
6292 
6293         /*
6294          * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
6295          * aligned blocks that are marked as MIGRATE_ISOLATE.  What's
6296          * more, all pages in [start, end) are free in page allocator.
6297          * What we are going to do is to allocate all pages from
6298          * [start, end) (that is remove them from page allocator).
6299          *
6300          * The only problem is that pages at the beginning and at the
6301          * end of interesting range may be not aligned with pages that
6302          * page allocator holds, ie. they can be part of higher order
6303          * pages.  Because of this, we reserve the bigger range and
6304          * once this is done free the pages we are not interested in.
6305          *
6306          * We don't have to hold zone->lock here because the pages are
6307          * isolated thus they won't get removed from buddy.
6308          */
6309 
6310         lru_add_drain_all();
6311         drain_all_pages();
6312 
6313         order = 0;
6314         outer_start = start;
6315         while (!PageBuddy(pfn_to_page(outer_start))) {
6316                 if (++order >= MAX_ORDER) {
6317                         ret = -EBUSY;
6318                         goto done;
6319                 }
6320                 outer_start &= ~0UL << order;
6321         }
6322 
6323         /* Make sure the range is really isolated. */
6324         if (test_pages_isolated(outer_start, end, false)) {
6325                 pr_warn("alloc_contig_range test_pages_isolated(%lx, %lx) failed\n",
6326                        outer_start, end);
6327                 ret = -EBUSY;
6328                 goto done;
6329         }
6330 
6331 
6332         /* Grab isolated pages from freelists. */
6333         outer_end = isolate_freepages_range(&cc, outer_start, end);
6334         if (!outer_end) {
6335                 ret = -EBUSY;
6336                 goto done;
6337         }
6338 
6339         /* Free head and tail (if any) */
6340         if (start != outer_start)
6341                 free_contig_range(outer_start, start - outer_start);
6342         if (end != outer_end)
6343                 free_contig_range(end, outer_end - end);
6344 
6345 done:
6346         undo_isolate_page_range(pfn_max_align_down(start),
6347                                 pfn_max_align_up(end), migratetype);
6348         return ret;
6349 }
6350 
6351 void free_contig_range(unsigned long pfn, unsigned nr_pages)
6352 {
6353         unsigned int count = 0;
6354 
6355         for (; nr_pages--; pfn++) {
6356                 struct page *page = pfn_to_page(pfn);
6357 
6358                 count += page_count(page) != 1;
6359                 __free_page(page);
6360         }
6361         WARN(count != 0, "%d pages are still in use!\n", count);
6362 }
6363 #endif
6364 
6365 #ifdef CONFIG_MEMORY_HOTPLUG
6366 /*
6367  * The zone indicated has a new number of managed_pages; batch sizes and percpu
6368  * page high values need to be recalulated.
6369  */
6370 void __meminit zone_pcp_update(struct zone *zone)
6371 {
6372         unsigned cpu;
6373         mutex_lock(&pcp_batch_high_lock);
6374         for_each_possible_cpu(cpu)
6375                 pageset_set_high_and_batch(zone,
6376                                 per_cpu_ptr(zone->pageset, cpu));
6377         mutex_unlock(&pcp_batch_high_lock);
6378 }
6379 #endif
6380 
6381 void zone_pcp_reset(struct zone *zone)
6382 {
6383         unsigned long flags;
6384         int cpu;
6385         struct per_cpu_pageset *pset;
6386 
6387         /* avoid races with drain_pages()  */
6388         local_irq_save(flags);
6389         if (zone->pageset != &boot_pageset) {
6390                 for_each_online_cpu(cpu) {
6391                         pset = per_cpu_ptr(zone->pageset, cpu);
6392                         drain_zonestat(zone, pset);
6393                 }
6394                 free_percpu(zone->pageset);
6395                 zone->pageset = &boot_pageset;
6396         }
6397         local_irq_restore(flags);
6398 }
6399 
6400 #ifdef CONFIG_MEMORY_HOTREMOVE
6401 /*
6402  * All pages in the range must be isolated before calling this.
6403  */
6404 void
6405 __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
6406 {
6407         struct page *page;
6408         struct zone *zone;
6409         int order, i;
6410         unsigned long pfn;
6411         unsigned long flags;
6412         /* find the first valid pfn */
6413         for (pfn = start_pfn; pfn < end_pfn; pfn++)
6414                 if (pfn_valid(pfn))
6415                         break;
6416         if (pfn == end_pfn)
6417                 return;
6418         zone = page_zone(pfn_to_page(pfn));
6419         spin_lock_irqsave(&zone->lock, flags);
6420         pfn = start_pfn;
6421         while (pfn < end_pfn) {
6422                 if (!pfn_valid(pfn)) {
6423                         pfn++;
6424                         continue;
6425                 }
6426                 page = pfn_to_page(pfn);
6427                 /*
6428                  * The HWPoisoned page may be not in buddy system, and
6429                  * page_count() is not 0.
6430                  */
6431                 if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
6432                         pfn++;
6433                         SetPageReserved(page);
6434                         continue;
6435                 }
6436 
6437                 BUG_ON(page_count(page));
6438                 BUG_ON(!PageBuddy(page));
6439                 order = page_order(page);
6440 #ifdef CONFIG_DEBUG_VM
6441                 printk(KERN_INFO "remove from free list %lx %d %lx\n",
6442                        pfn, 1 << order, end_pfn);
6443 #endif
6444                 list_del(&page->lru);
6445                 rmv_page_order(page);
6446                 zone->free_area[order].nr_free--;
6447                 for (i = 0; i < (1 << order); i++)
6448                         SetPageReserved((page+i));
6449                 pfn += (1 << order);
6450         }
6451         spin_unlock_irqrestore(&zone->lock, flags);
6452 }
6453 #endif
6454 
6455 #ifdef CONFIG_MEMORY_FAILURE
6456 bool is_free_buddy_page(struct page *page)
6457 {
6458         struct zone *zone = page_zone(page);
6459         unsigned long pfn = page_to_pfn(page);
6460         unsigned long flags;
6461         int order;
6462 
6463         spin_lock_irqsave(&zone->lock, flags);
6464         for (order = 0; order < MAX_ORDER; order++) {
6465                 struct page *page_head = page - (pfn & ((1 << order) - 1));
6466 
6467                 if (PageBuddy(page_head) && page_order(page_head) >= order)
6468                         break;
6469         }
6470         spin_unlock_irqrestore(&zone->lock, flags);
6471 
6472         return order < MAX_ORDER;
6473 }
6474 #endif
6475 
6476 static const struct trace_print_flags pageflag_names[] = {
6477         {1UL << PG_locked,              "locked"        },
6478         {1UL << PG_error,               "error"         },
6479         {1UL << PG_referenced,          "referenced"    },
6480         {1UL << PG_uptodate,            "uptodate"      },
6481         {1UL << PG_dirty,               "dirty"         },
6482         {1UL << PG_lru,                 "lru"           },
6483         {1UL << PG_active,              "active"        },
6484         {1UL << PG_slab,                "slab"          },
6485         {1UL << PG_owner_priv_1,        "owner_priv_1"  },
6486         {1UL << PG_arch_1,              "arch_1"        },
6487         {1UL << PG_reserved,            "reserved"      },
6488         {1UL << PG_private,             "private"       },
6489         {1UL << PG_private_2,           "private_2"     },
6490         {1UL << PG_writeback,           "writeback"     },
6491 #ifdef CONFIG_PAGEFLAGS_EXTENDED
6492         {1UL << PG_head,                "head"          },
6493         {1UL << PG_tail,                "tail"          },
6494 #else
6495         {1UL << PG_compound,            "compound"      },
6496 #endif
6497         {1UL << PG_swapcache,           "swapcache"     },
6498         {1UL << PG_mappedtodisk,        "mappedtodisk"  },
6499         {1UL << PG_reclaim,             "reclaim"       },
6500         {1UL << PG_swapbacked,          "swapbacked"    },
6501         {1UL << PG_unevictable,         "unevictable"   },
6502 #ifdef CONFIG_MMU
6503         {1UL << PG_mlocked,             "mlocked"       },
6504 #endif
6505 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
6506         {1UL << PG_uncached,            "uncached"      },
6507 #endif
6508 #ifdef CONFIG_MEMORY_FAILURE
6509         {1UL << PG_hwpoison,            "hwpoison"      },
6510 #endif
6511 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6512         {1UL << PG_compound_lock,       "compound_lock" },
6513 #endif
6514 };
6515 
6516 static void dump_page_flags(unsigned long flags)
6517 {
6518         const char *delim = "";
6519         unsigned long mask;
6520         int i;
6521 
6522         BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS);
6523 
6524         printk(KERN_ALERT "page flags: %#lx(", flags);
6525 
6526         /* remove zone id */
6527         flags &= (1UL << NR_PAGEFLAGS) - 1;
6528 
6529         for (i = 0; i < ARRAY_SIZE(pageflag_names) && flags; i++) {
6530 
6531                 mask = pageflag_names[i].mask;
6532                 if ((flags & mask) != mask)
6533                         continue;
6534 
6535                 flags &= ~mask;
6536                 printk("%s%s", delim, pageflag_names[i].name);
6537                 delim = "|";
6538         }
6539 
6540         /* check for left over flags */
6541         if (flags)
6542                 printk("%s%#lx", delim, flags);
6543 
6544         printk(")\n");
6545 }
6546 
6547 void dump_page_badflags(struct page *page, char *reason, unsigned long badflags)
6548 {
6549         printk(KERN_ALERT
6550                "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
6551                 page, atomic_read(&page->_count), page_mapcount(page),
6552                 page->mapping, page->index);
6553         dump_page_flags(page->flags);
6554         if (reason)
6555                 pr_alert("page dumped because: %s\n", reason);
6556         if (page->flags & badflags) {
6557                 pr_alert("bad because of flags:\n");
6558                 dump_page_flags(page->flags & badflags);
6559         }
6560         mem_cgroup_print_bad_page(page);
6561 }
6562 
6563 void dump_page(struct page *page, char *reason)
6564 {
6565         dump_page_badflags(page, reason, 0);
6566 }
6567 EXPORT_SYMBOL_GPL(dump_page);
6568 

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