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TOMOYO Linux Cross Reference
Linux/mm/page_alloc.c

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  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/memory.h>
 55 #include <linux/compaction.h>
 56 #include <trace/events/kmem.h>
 57 #include <linux/ftrace_event.h>
 58 #include <linux/memcontrol.h>
 59 #include <linux/prefetch.h>
 60 
 61 #include <asm/tlbflush.h>
 62 #include <asm/div64.h>
 63 #include "internal.h"
 64 
 65 #ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
 66 DEFINE_PER_CPU(int, numa_node);
 67 EXPORT_PER_CPU_SYMBOL(numa_node);
 68 #endif
 69 
 70 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
 71 /*
 72  * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
 73  * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
 74  * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
 75  * defined in <linux/topology.h>.
 76  */
 77 DEFINE_PER_CPU(int, _numa_mem_);                /* Kernel "local memory" node */
 78 EXPORT_PER_CPU_SYMBOL(_numa_mem_);
 79 #endif
 80 
 81 /*
 82  * Array of node states.
 83  */
 84 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
 85         [N_POSSIBLE] = NODE_MASK_ALL,
 86         [N_ONLINE] = { { [0] = 1UL } },
 87 #ifndef CONFIG_NUMA
 88         [N_NORMAL_MEMORY] = { { [0] = 1UL } },
 89 #ifdef CONFIG_HIGHMEM
 90         [N_HIGH_MEMORY] = { { [0] = 1UL } },
 91 #endif
 92         [N_CPU] = { { [0] = 1UL } },
 93 #endif  /* NUMA */
 94 };
 95 EXPORT_SYMBOL(node_states);
 96 
 97 unsigned long totalram_pages __read_mostly;
 98 unsigned long totalreserve_pages __read_mostly;
 99 int percpu_pagelist_fraction;
100 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
101 
102 #ifdef CONFIG_PM_SLEEP
103 /*
104  * The following functions are used by the suspend/hibernate code to temporarily
105  * change gfp_allowed_mask in order to avoid using I/O during memory allocations
106  * while devices are suspended.  To avoid races with the suspend/hibernate code,
107  * they should always be called with pm_mutex held (gfp_allowed_mask also should
108  * only be modified with pm_mutex held, unless the suspend/hibernate code is
109  * guaranteed not to run in parallel with that modification).
110  */
111 
112 static gfp_t saved_gfp_mask;
113 
114 void pm_restore_gfp_mask(void)
115 {
116         WARN_ON(!mutex_is_locked(&pm_mutex));
117         if (saved_gfp_mask) {
118                 gfp_allowed_mask = saved_gfp_mask;
119                 saved_gfp_mask = 0;
120         }
121 }
122 
123 void pm_restrict_gfp_mask(void)
124 {
125         WARN_ON(!mutex_is_locked(&pm_mutex));
126         WARN_ON(saved_gfp_mask);
127         saved_gfp_mask = gfp_allowed_mask;
128         gfp_allowed_mask &= ~GFP_IOFS;
129 }
130 #endif /* CONFIG_PM_SLEEP */
131 
132 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
133 int pageblock_order __read_mostly;
134 #endif
135 
136 static void __free_pages_ok(struct page *page, unsigned int order);
137 
138 /*
139  * results with 256, 32 in the lowmem_reserve sysctl:
140  *      1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
141  *      1G machine -> (16M dma, 784M normal, 224M high)
142  *      NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
143  *      HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
144  *      HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
145  *
146  * TBD: should special case ZONE_DMA32 machines here - in those we normally
147  * don't need any ZONE_NORMAL reservation
148  */
149 int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
150 #ifdef CONFIG_ZONE_DMA
151          256,
152 #endif
153 #ifdef CONFIG_ZONE_DMA32
154          256,
155 #endif
156 #ifdef CONFIG_HIGHMEM
157          32,
158 #endif
159          32,
160 };
161 
162 EXPORT_SYMBOL(totalram_pages);
163 
164 static char * const zone_names[MAX_NR_ZONES] = {
165 #ifdef CONFIG_ZONE_DMA
166          "DMA",
167 #endif
168 #ifdef CONFIG_ZONE_DMA32
169          "DMA32",
170 #endif
171          "Normal",
172 #ifdef CONFIG_HIGHMEM
173          "HighMem",
174 #endif
175          "Movable",
176 };
177 
178 int min_free_kbytes = 1024;
179 
180 static unsigned long __meminitdata nr_kernel_pages;
181 static unsigned long __meminitdata nr_all_pages;
182 static unsigned long __meminitdata dma_reserve;
183 
184 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
185   /*
186    * MAX_ACTIVE_REGIONS determines the maximum number of distinct
187    * ranges of memory (RAM) that may be registered with add_active_range().
188    * Ranges passed to add_active_range() will be merged if possible
189    * so the number of times add_active_range() can be called is
190    * related to the number of nodes and the number of holes
191    */
192   #ifdef CONFIG_MAX_ACTIVE_REGIONS
193     /* Allow an architecture to set MAX_ACTIVE_REGIONS to save memory */
194     #define MAX_ACTIVE_REGIONS CONFIG_MAX_ACTIVE_REGIONS
195   #else
196     #if MAX_NUMNODES >= 32
197       /* If there can be many nodes, allow up to 50 holes per node */
198       #define MAX_ACTIVE_REGIONS (MAX_NUMNODES*50)
199     #else
200       /* By default, allow up to 256 distinct regions */
201       #define MAX_ACTIVE_REGIONS 256
202     #endif
203   #endif
204 
205   static struct node_active_region __meminitdata early_node_map[MAX_ACTIVE_REGIONS];
206   static int __meminitdata nr_nodemap_entries;
207   static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
208   static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
209   static unsigned long __initdata required_kernelcore;
210   static unsigned long __initdata required_movablecore;
211   static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
212 
213   /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
214   int movable_zone;
215   EXPORT_SYMBOL(movable_zone);
216 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
217 
218 #if MAX_NUMNODES > 1
219 int nr_node_ids __read_mostly = MAX_NUMNODES;
220 int nr_online_nodes __read_mostly = 1;
221 EXPORT_SYMBOL(nr_node_ids);
222 EXPORT_SYMBOL(nr_online_nodes);
223 #endif
224 
225 int page_group_by_mobility_disabled __read_mostly;
226 
227 static void set_pageblock_migratetype(struct page *page, int migratetype)
228 {
229 
230         if (unlikely(page_group_by_mobility_disabled))
231                 migratetype = MIGRATE_UNMOVABLE;
232 
233         set_pageblock_flags_group(page, (unsigned long)migratetype,
234                                         PB_migrate, PB_migrate_end);
235 }
236 
237 bool oom_killer_disabled __read_mostly;
238 
239 #ifdef CONFIG_DEBUG_VM
240 static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
241 {
242         int ret = 0;
243         unsigned seq;
244         unsigned long pfn = page_to_pfn(page);
245 
246         do {
247                 seq = zone_span_seqbegin(zone);
248                 if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
249                         ret = 1;
250                 else if (pfn < zone->zone_start_pfn)
251                         ret = 1;
252         } while (zone_span_seqretry(zone, seq));
253 
254         return ret;
255 }
256 
257 static int page_is_consistent(struct zone *zone, struct page *page)
258 {
259         if (!pfn_valid_within(page_to_pfn(page)))
260                 return 0;
261         if (zone != page_zone(page))
262                 return 0;
263 
264         return 1;
265 }
266 /*
267  * Temporary debugging check for pages not lying within a given zone.
268  */
269 static int bad_range(struct zone *zone, struct page *page)
270 {
271         if (page_outside_zone_boundaries(zone, page))
272                 return 1;
273         if (!page_is_consistent(zone, page))
274                 return 1;
275 
276         return 0;
277 }
278 #else
279 static inline int bad_range(struct zone *zone, struct page *page)
280 {
281         return 0;
282 }
283 #endif
284 
285 static void bad_page(struct page *page)
286 {
287         static unsigned long resume;
288         static unsigned long nr_shown;
289         static unsigned long nr_unshown;
290 
291         /* Don't complain about poisoned pages */
292         if (PageHWPoison(page)) {
293                 reset_page_mapcount(page); /* remove PageBuddy */
294                 return;
295         }
296 
297         /*
298          * Allow a burst of 60 reports, then keep quiet for that minute;
299          * or allow a steady drip of one report per second.
300          */
301         if (nr_shown == 60) {
302                 if (time_before(jiffies, resume)) {
303                         nr_unshown++;
304                         goto out;
305                 }
306                 if (nr_unshown) {
307                         printk(KERN_ALERT
308                               "BUG: Bad page state: %lu messages suppressed\n",
309                                 nr_unshown);
310                         nr_unshown = 0;
311                 }
312                 nr_shown = 0;
313         }
314         if (nr_shown++ == 0)
315                 resume = jiffies + 60 * HZ;
316 
317         printk(KERN_ALERT "BUG: Bad page state in process %s  pfn:%05lx\n",
318                 current->comm, page_to_pfn(page));
319         dump_page(page);
320 
321         dump_stack();
322 out:
323         /* Leave bad fields for debug, except PageBuddy could make trouble */
324         reset_page_mapcount(page); /* remove PageBuddy */
325         add_taint(TAINT_BAD_PAGE);
326 }
327 
328 /*
329  * Higher-order pages are called "compound pages".  They are structured thusly:
330  *
331  * The first PAGE_SIZE page is called the "head page".
332  *
333  * The remaining PAGE_SIZE pages are called "tail pages".
334  *
335  * All pages have PG_compound set.  All pages have their ->private pointing at
336  * the head page (even the head page has this).
337  *
338  * The first tail page's ->lru.next holds the address of the compound page's
339  * put_page() function.  Its ->lru.prev holds the order of allocation.
340  * This usage means that zero-order pages may not be compound.
341  */
342 
343 static void free_compound_page(struct page *page)
344 {
345         __free_pages_ok(page, compound_order(page));
346 }
347 
348 void prep_compound_page(struct page *page, unsigned long order)
349 {
350         int i;
351         int nr_pages = 1 << order;
352 
353         set_compound_page_dtor(page, free_compound_page);
354         set_compound_order(page, order);
355         __SetPageHead(page);
356         for (i = 1; i < nr_pages; i++) {
357                 struct page *p = page + i;
358                 __SetPageTail(p);
359                 set_page_count(p, 0);
360                 p->first_page = page;
361         }
362 }
363 
364 /* update __split_huge_page_refcount if you change this function */
365 static int destroy_compound_page(struct page *page, unsigned long order)
366 {
367         int i;
368         int nr_pages = 1 << order;
369         int bad = 0;
370 
371         if (unlikely(compound_order(page) != order) ||
372             unlikely(!PageHead(page))) {
373                 bad_page(page);
374                 bad++;
375         }
376 
377         __ClearPageHead(page);
378 
379         for (i = 1; i < nr_pages; i++) {
380                 struct page *p = page + i;
381 
382                 if (unlikely(!PageTail(p) || (p->first_page != page))) {
383                         bad_page(page);
384                         bad++;
385                 }
386                 __ClearPageTail(p);
387         }
388 
389         return bad;
390 }
391 
392 static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
393 {
394         int i;
395 
396         /*
397          * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
398          * and __GFP_HIGHMEM from hard or soft interrupt context.
399          */
400         VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
401         for (i = 0; i < (1 << order); i++)
402                 clear_highpage(page + i);
403 }
404 
405 static inline void set_page_order(struct page *page, int order)
406 {
407         set_page_private(page, order);
408         __SetPageBuddy(page);
409 }
410 
411 static inline void rmv_page_order(struct page *page)
412 {
413         __ClearPageBuddy(page);
414         set_page_private(page, 0);
415 }
416 
417 /*
418  * Locate the struct page for both the matching buddy in our
419  * pair (buddy1) and the combined O(n+1) page they form (page).
420  *
421  * 1) Any buddy B1 will have an order O twin B2 which satisfies
422  * the following equation:
423  *     B2 = B1 ^ (1 << O)
424  * For example, if the starting buddy (buddy2) is #8 its order
425  * 1 buddy is #10:
426  *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
427  *
428  * 2) Any buddy B will have an order O+1 parent P which
429  * satisfies the following equation:
430  *     P = B & ~(1 << O)
431  *
432  * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
433  */
434 static inline unsigned long
435 __find_buddy_index(unsigned long page_idx, unsigned int order)
436 {
437         return page_idx ^ (1 << order);
438 }
439 
440 /*
441  * This function checks whether a page is free && is the buddy
442  * we can do coalesce a page and its buddy if
443  * (a) the buddy is not in a hole &&
444  * (b) the buddy is in the buddy system &&
445  * (c) a page and its buddy have the same order &&
446  * (d) a page and its buddy are in the same zone.
447  *
448  * For recording whether a page is in the buddy system, we set ->_mapcount -2.
449  * Setting, clearing, and testing _mapcount -2 is serialized by zone->lock.
450  *
451  * For recording page's order, we use page_private(page).
452  */
453 static inline int page_is_buddy(struct page *page, struct page *buddy,
454                                                                 int order)
455 {
456         if (!pfn_valid_within(page_to_pfn(buddy)))
457                 return 0;
458 
459         if (page_zone_id(page) != page_zone_id(buddy))
460                 return 0;
461 
462         if (PageBuddy(buddy) && page_order(buddy) == order) {
463                 VM_BUG_ON(page_count(buddy) != 0);
464                 return 1;
465         }
466         return 0;
467 }
468 
469 /*
470  * Freeing function for a buddy system allocator.
471  *
472  * The concept of a buddy system is to maintain direct-mapped table
473  * (containing bit values) for memory blocks of various "orders".
474  * The bottom level table contains the map for the smallest allocatable
475  * units of memory (here, pages), and each level above it describes
476  * pairs of units from the levels below, hence, "buddies".
477  * At a high level, all that happens here is marking the table entry
478  * at the bottom level available, and propagating the changes upward
479  * as necessary, plus some accounting needed to play nicely with other
480  * parts of the VM system.
481  * At each level, we keep a list of pages, which are heads of continuous
482  * free pages of length of (1 << order) and marked with _mapcount -2. Page's
483  * order is recorded in page_private(page) field.
484  * So when we are allocating or freeing one, we can derive the state of the
485  * other.  That is, if we allocate a small block, and both were   
486  * free, the remainder of the region must be split into blocks.   
487  * If a block is freed, and its buddy is also free, then this
488  * triggers coalescing into a block of larger size.            
489  *
490  * -- wli
491  */
492 
493 static inline void __free_one_page(struct page *page,
494                 struct zone *zone, unsigned int order,
495                 int migratetype)
496 {
497         unsigned long page_idx;
498         unsigned long combined_idx;
499         unsigned long uninitialized_var(buddy_idx);
500         struct page *buddy;
501 
502         if (unlikely(PageCompound(page)))
503                 if (unlikely(destroy_compound_page(page, order)))
504                         return;
505 
506         VM_BUG_ON(migratetype == -1);
507 
508         page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
509 
510         VM_BUG_ON(page_idx & ((1 << order) - 1));
511         VM_BUG_ON(bad_range(zone, page));
512 
513         while (order < MAX_ORDER-1) {
514                 buddy_idx = __find_buddy_index(page_idx, order);
515                 buddy = page + (buddy_idx - page_idx);
516                 if (!page_is_buddy(page, buddy, order))
517                         break;
518 
519                 /* Our buddy is free, merge with it and move up one order. */
520                 list_del(&buddy->lru);
521                 zone->free_area[order].nr_free--;
522                 rmv_page_order(buddy);
523                 combined_idx = buddy_idx & page_idx;
524                 page = page + (combined_idx - page_idx);
525                 page_idx = combined_idx;
526                 order++;
527         }
528         set_page_order(page, order);
529 
530         /*
531          * If this is not the largest possible page, check if the buddy
532          * of the next-highest order is free. If it is, it's possible
533          * that pages are being freed that will coalesce soon. In case,
534          * that is happening, add the free page to the tail of the list
535          * so it's less likely to be used soon and more likely to be merged
536          * as a higher order page
537          */
538         if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
539                 struct page *higher_page, *higher_buddy;
540                 combined_idx = buddy_idx & page_idx;
541                 higher_page = page + (combined_idx - page_idx);
542                 buddy_idx = __find_buddy_index(combined_idx, order + 1);
543                 higher_buddy = higher_page + (buddy_idx - combined_idx);
544                 if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
545                         list_add_tail(&page->lru,
546                                 &zone->free_area[order].free_list[migratetype]);
547                         goto out;
548                 }
549         }
550 
551         list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
552 out:
553         zone->free_area[order].nr_free++;
554 }
555 
556 /*
557  * free_page_mlock() -- clean up attempts to free and mlocked() page.
558  * Page should not be on lru, so no need to fix that up.
559  * free_pages_check() will verify...
560  */
561 static inline void free_page_mlock(struct page *page)
562 {
563         __dec_zone_page_state(page, NR_MLOCK);
564         __count_vm_event(UNEVICTABLE_MLOCKFREED);
565 }
566 
567 static inline int free_pages_check(struct page *page)
568 {
569         if (unlikely(page_mapcount(page) |
570                 (page->mapping != NULL)  |
571                 (atomic_read(&page->_count) != 0) |
572                 (page->flags & PAGE_FLAGS_CHECK_AT_FREE) |
573                 (mem_cgroup_bad_page_check(page)))) {
574                 bad_page(page);
575                 return 1;
576         }
577         if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
578                 page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
579         return 0;
580 }
581 
582 /*
583  * Frees a number of pages from the PCP lists
584  * Assumes all pages on list are in same zone, and of same order.
585  * count is the number of pages to free.
586  *
587  * If the zone was previously in an "all pages pinned" state then look to
588  * see if this freeing clears that state.
589  *
590  * And clear the zone's pages_scanned counter, to hold off the "all pages are
591  * pinned" detection logic.
592  */
593 static void free_pcppages_bulk(struct zone *zone, int count,
594                                         struct per_cpu_pages *pcp)
595 {
596         int migratetype = 0;
597         int batch_free = 0;
598         int to_free = count;
599 
600         spin_lock(&zone->lock);
601         zone->all_unreclaimable = 0;
602         zone->pages_scanned = 0;
603 
604         while (to_free) {
605                 struct page *page;
606                 struct list_head *list;
607 
608                 /*
609                  * Remove pages from lists in a round-robin fashion. A
610                  * batch_free count is maintained that is incremented when an
611                  * empty list is encountered.  This is so more pages are freed
612                  * off fuller lists instead of spinning excessively around empty
613                  * lists
614                  */
615                 do {
616                         batch_free++;
617                         if (++migratetype == MIGRATE_PCPTYPES)
618                                 migratetype = 0;
619                         list = &pcp->lists[migratetype];
620                 } while (list_empty(list));
621 
622                 /* This is the only non-empty list. Free them all. */
623                 if (batch_free == MIGRATE_PCPTYPES)
624                         batch_free = to_free;
625 
626                 do {
627                         page = list_entry(list->prev, struct page, lru);
628                         /* must delete as __free_one_page list manipulates */
629                         list_del(&page->lru);
630                         /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
631                         __free_one_page(page, zone, 0, page_private(page));
632                         trace_mm_page_pcpu_drain(page, 0, page_private(page));
633                 } while (--to_free && --batch_free && !list_empty(list));
634         }
635         __mod_zone_page_state(zone, NR_FREE_PAGES, count);
636         spin_unlock(&zone->lock);
637 }
638 
639 static void free_one_page(struct zone *zone, struct page *page, int order,
640                                 int migratetype)
641 {
642         spin_lock(&zone->lock);
643         zone->all_unreclaimable = 0;
644         zone->pages_scanned = 0;
645 
646         __free_one_page(page, zone, order, migratetype);
647         __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
648         spin_unlock(&zone->lock);
649 }
650 
651 static bool free_pages_prepare(struct page *page, unsigned int order)
652 {
653         int i;
654         int bad = 0;
655 
656         trace_mm_page_free_direct(page, order);
657         kmemcheck_free_shadow(page, order);
658 
659         if (PageAnon(page))
660                 page->mapping = NULL;
661         for (i = 0; i < (1 << order); i++)
662                 bad += free_pages_check(page + i);
663         if (bad)
664                 return false;
665 
666         if (!PageHighMem(page)) {
667                 debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
668                 debug_check_no_obj_freed(page_address(page),
669                                            PAGE_SIZE << order);
670         }
671         arch_free_page(page, order);
672         kernel_map_pages(page, 1 << order, 0);
673 
674         return true;
675 }
676 
677 static void __free_pages_ok(struct page *page, unsigned int order)
678 {
679         unsigned long flags;
680         int wasMlocked = __TestClearPageMlocked(page);
681 
682         if (!free_pages_prepare(page, order))
683                 return;
684 
685         local_irq_save(flags);
686         if (unlikely(wasMlocked))
687                 free_page_mlock(page);
688         __count_vm_events(PGFREE, 1 << order);
689         free_one_page(page_zone(page), page, order,
690                                         get_pageblock_migratetype(page));
691         local_irq_restore(flags);
692 }
693 
694 /*
695  * permit the bootmem allocator to evade page validation on high-order frees
696  */
697 void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
698 {
699         if (order == 0) {
700                 __ClearPageReserved(page);
701                 set_page_count(page, 0);
702                 set_page_refcounted(page);
703                 __free_page(page);
704         } else {
705                 int loop;
706 
707                 prefetchw(page);
708                 for (loop = 0; loop < BITS_PER_LONG; loop++) {
709                         struct page *p = &page[loop];
710 
711                         if (loop + 1 < BITS_PER_LONG)
712                                 prefetchw(p + 1);
713                         __ClearPageReserved(p);
714                         set_page_count(p, 0);
715                 }
716 
717                 set_page_refcounted(page);
718                 __free_pages(page, order);
719         }
720 }
721 
722 
723 /*
724  * The order of subdivision here is critical for the IO subsystem.
725  * Please do not alter this order without good reasons and regression
726  * testing. Specifically, as large blocks of memory are subdivided,
727  * the order in which smaller blocks are delivered depends on the order
728  * they're subdivided in this function. This is the primary factor
729  * influencing the order in which pages are delivered to the IO
730  * subsystem according to empirical testing, and this is also justified
731  * by considering the behavior of a buddy system containing a single
732  * large block of memory acted on by a series of small allocations.
733  * This behavior is a critical factor in sglist merging's success.
734  *
735  * -- wli
736  */
737 static inline void expand(struct zone *zone, struct page *page,
738         int low, int high, struct free_area *area,
739         int migratetype)
740 {
741         unsigned long size = 1 << high;
742 
743         while (high > low) {
744                 area--;
745                 high--;
746                 size >>= 1;
747                 VM_BUG_ON(bad_range(zone, &page[size]));
748                 list_add(&page[size].lru, &area->free_list[migratetype]);
749                 area->nr_free++;
750                 set_page_order(&page[size], high);
751         }
752 }
753 
754 /*
755  * This page is about to be returned from the page allocator
756  */
757 static inline int check_new_page(struct page *page)
758 {
759         if (unlikely(page_mapcount(page) |
760                 (page->mapping != NULL)  |
761                 (atomic_read(&page->_count) != 0)  |
762                 (page->flags & PAGE_FLAGS_CHECK_AT_PREP) |
763                 (mem_cgroup_bad_page_check(page)))) {
764                 bad_page(page);
765                 return 1;
766         }
767         return 0;
768 }
769 
770 static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
771 {
772         int i;
773 
774         for (i = 0; i < (1 << order); i++) {
775                 struct page *p = page + i;
776                 if (unlikely(check_new_page(p)))
777                         return 1;
778         }
779 
780         set_page_private(page, 0);
781         set_page_refcounted(page);
782 
783         arch_alloc_page(page, order);
784         kernel_map_pages(page, 1 << order, 1);
785 
786         if (gfp_flags & __GFP_ZERO)
787                 prep_zero_page(page, order, gfp_flags);
788 
789         if (order && (gfp_flags & __GFP_COMP))
790                 prep_compound_page(page, order);
791 
792         return 0;
793 }
794 
795 /*
796  * Go through the free lists for the given migratetype and remove
797  * the smallest available page from the freelists
798  */
799 static inline
800 struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
801                                                 int migratetype)
802 {
803         unsigned int current_order;
804         struct free_area * area;
805         struct page *page;
806 
807         /* Find a page of the appropriate size in the preferred list */
808         for (current_order = order; current_order < MAX_ORDER; ++current_order) {
809                 area = &(zone->free_area[current_order]);
810                 if (list_empty(&area->free_list[migratetype]))
811                         continue;
812 
813                 page = list_entry(area->free_list[migratetype].next,
814                                                         struct page, lru);
815                 list_del(&page->lru);
816                 rmv_page_order(page);
817                 area->nr_free--;
818                 expand(zone, page, order, current_order, area, migratetype);
819                 return page;
820         }
821 
822         return NULL;
823 }
824 
825 
826 /*
827  * This array describes the order lists are fallen back to when
828  * the free lists for the desirable migrate type are depleted
829  */
830 static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = {
831         [MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_RESERVE },
832         [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_RESERVE },
833         [MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
834         [MIGRATE_RESERVE]     = { MIGRATE_RESERVE,     MIGRATE_RESERVE,   MIGRATE_RESERVE }, /* Never used */
835 };
836 
837 /*
838  * Move the free pages in a range to the free lists of the requested type.
839  * Note that start_page and end_pages are not aligned on a pageblock
840  * boundary. If alignment is required, use move_freepages_block()
841  */
842 static int move_freepages(struct zone *zone,
843                           struct page *start_page, struct page *end_page,
844                           int migratetype)
845 {
846         struct page *page;
847         unsigned long order;
848         int pages_moved = 0;
849 
850 #ifndef CONFIG_HOLES_IN_ZONE
851         /*
852          * page_zone is not safe to call in this context when
853          * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
854          * anyway as we check zone boundaries in move_freepages_block().
855          * Remove at a later date when no bug reports exist related to
856          * grouping pages by mobility
857          */
858         BUG_ON(page_zone(start_page) != page_zone(end_page));
859 #endif
860 
861         for (page = start_page; page <= end_page;) {
862                 /* Make sure we are not inadvertently changing nodes */
863                 VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
864 
865                 if (!pfn_valid_within(page_to_pfn(page))) {
866                         page++;
867                         continue;
868                 }
869 
870                 if (!PageBuddy(page)) {
871                         page++;
872                         continue;
873                 }
874 
875                 order = page_order(page);
876                 list_move(&page->lru,
877                           &zone->free_area[order].free_list[migratetype]);
878                 page += 1 << order;
879                 pages_moved += 1 << order;
880         }
881 
882         return pages_moved;
883 }
884 
885 static int move_freepages_block(struct zone *zone, struct page *page,
886                                 int migratetype)
887 {
888         unsigned long start_pfn, end_pfn;
889         struct page *start_page, *end_page;
890 
891         start_pfn = page_to_pfn(page);
892         start_pfn = start_pfn & ~(pageblock_nr_pages-1);
893         start_page = pfn_to_page(start_pfn);
894         end_page = start_page + pageblock_nr_pages - 1;
895         end_pfn = start_pfn + pageblock_nr_pages - 1;
896 
897         /* Do not cross zone boundaries */
898         if (start_pfn < zone->zone_start_pfn)
899                 start_page = page;
900         if (end_pfn >= zone->zone_start_pfn + zone->spanned_pages)
901                 return 0;
902 
903         return move_freepages(zone, start_page, end_page, migratetype);
904 }
905 
906 static void change_pageblock_range(struct page *pageblock_page,
907                                         int start_order, int migratetype)
908 {
909         int nr_pageblocks = 1 << (start_order - pageblock_order);
910 
911         while (nr_pageblocks--) {
912                 set_pageblock_migratetype(pageblock_page, migratetype);
913                 pageblock_page += pageblock_nr_pages;
914         }
915 }
916 
917 /* Remove an element from the buddy allocator from the fallback list */
918 static inline struct page *
919 __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
920 {
921         struct free_area * area;
922         int current_order;
923         struct page *page;
924         int migratetype, i;
925 
926         /* Find the largest possible block of pages in the other list */
927         for (current_order = MAX_ORDER-1; current_order >= order;
928                                                 --current_order) {
929                 for (i = 0; i < MIGRATE_TYPES - 1; i++) {
930                         migratetype = fallbacks[start_migratetype][i];
931 
932                         /* MIGRATE_RESERVE handled later if necessary */
933                         if (migratetype == MIGRATE_RESERVE)
934                                 continue;
935 
936                         area = &(zone->free_area[current_order]);
937                         if (list_empty(&area->free_list[migratetype]))
938                                 continue;
939 
940                         page = list_entry(area->free_list[migratetype].next,
941                                         struct page, lru);
942                         area->nr_free--;
943 
944                         /*
945                          * If breaking a large block of pages, move all free
946                          * pages to the preferred allocation list. If falling
947                          * back for a reclaimable kernel allocation, be more
948                          * aggressive about taking ownership of free pages
949                          */
950                         if (unlikely(current_order >= (pageblock_order >> 1)) ||
951                                         start_migratetype == MIGRATE_RECLAIMABLE ||
952                                         page_group_by_mobility_disabled) {
953                                 unsigned long pages;
954                                 pages = move_freepages_block(zone, page,
955                                                                 start_migratetype);
956 
957                                 /* Claim the whole block if over half of it is free */
958                                 if (pages >= (1 << (pageblock_order-1)) ||
959                                                 page_group_by_mobility_disabled)
960                                         set_pageblock_migratetype(page,
961                                                                 start_migratetype);
962 
963                                 migratetype = start_migratetype;
964                         }
965 
966                         /* Remove the page from the freelists */
967                         list_del(&page->lru);
968                         rmv_page_order(page);
969 
970                         /* Take ownership for orders >= pageblock_order */
971                         if (current_order >= pageblock_order)
972                                 change_pageblock_range(page, current_order,
973                                                         start_migratetype);
974 
975                         expand(zone, page, order, current_order, area, migratetype);
976 
977                         trace_mm_page_alloc_extfrag(page, order, current_order,
978                                 start_migratetype, migratetype);
979 
980                         return page;
981                 }
982         }
983 
984         return NULL;
985 }
986 
987 /*
988  * Do the hard work of removing an element from the buddy allocator.
989  * Call me with the zone->lock already held.
990  */
991 static struct page *__rmqueue(struct zone *zone, unsigned int order,
992                                                 int migratetype)
993 {
994         struct page *page;
995 
996 retry_reserve:
997         page = __rmqueue_smallest(zone, order, migratetype);
998 
999         if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
1000                 page = __rmqueue_fallback(zone, order, migratetype);
1001 
1002                 /*
1003                  * Use MIGRATE_RESERVE rather than fail an allocation. goto
1004                  * is used because __rmqueue_smallest is an inline function
1005                  * and we want just one call site
1006                  */
1007                 if (!page) {
1008                         migratetype = MIGRATE_RESERVE;
1009                         goto retry_reserve;
1010                 }
1011         }
1012 
1013         trace_mm_page_alloc_zone_locked(page, order, migratetype);
1014         return page;
1015 }
1016 
1017 /* 
1018  * Obtain a specified number of elements from the buddy allocator, all under
1019  * a single hold of the lock, for efficiency.  Add them to the supplied list.
1020  * Returns the number of new pages which were placed at *list.
1021  */
1022 static int rmqueue_bulk(struct zone *zone, unsigned int order, 
1023                         unsigned long count, struct list_head *list,
1024                         int migratetype, int cold)
1025 {
1026         int i;
1027         
1028         spin_lock(&zone->lock);
1029         for (i = 0; i < count; ++i) {
1030                 struct page *page = __rmqueue(zone, order, migratetype);
1031                 if (unlikely(page == NULL))
1032                         break;
1033 
1034                 /*
1035                  * Split buddy pages returned by expand() are received here
1036                  * in physical page order. The page is added to the callers and
1037                  * list and the list head then moves forward. From the callers
1038                  * perspective, the linked list is ordered by page number in
1039                  * some conditions. This is useful for IO devices that can
1040                  * merge IO requests if the physical pages are ordered
1041                  * properly.
1042                  */
1043                 if (likely(cold == 0))
1044                         list_add(&page->lru, list);
1045                 else
1046                         list_add_tail(&page->lru, list);
1047                 set_page_private(page, migratetype);
1048                 list = &page->lru;
1049         }
1050         __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
1051         spin_unlock(&zone->lock);
1052         return i;
1053 }
1054 
1055 #ifdef CONFIG_NUMA
1056 /*
1057  * Called from the vmstat counter updater to drain pagesets of this
1058  * currently executing processor on remote nodes after they have
1059  * expired.
1060  *
1061  * Note that this function must be called with the thread pinned to
1062  * a single processor.
1063  */
1064 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
1065 {
1066         unsigned long flags;
1067         int to_drain;
1068 
1069         local_irq_save(flags);
1070         if (pcp->count >= pcp->batch)
1071                 to_drain = pcp->batch;
1072         else
1073                 to_drain = pcp->count;
1074         free_pcppages_bulk(zone, to_drain, pcp);
1075         pcp->count -= to_drain;
1076         local_irq_restore(flags);
1077 }
1078 #endif
1079 
1080 /*
1081  * Drain pages of the indicated processor.
1082  *
1083  * The processor must either be the current processor and the
1084  * thread pinned to the current processor or a processor that
1085  * is not online.
1086  */
1087 static void drain_pages(unsigned int cpu)
1088 {
1089         unsigned long flags;
1090         struct zone *zone;
1091 
1092         for_each_populated_zone(zone) {
1093                 struct per_cpu_pageset *pset;
1094                 struct per_cpu_pages *pcp;
1095 
1096                 local_irq_save(flags);
1097                 pset = per_cpu_ptr(zone->pageset, cpu);
1098 
1099                 pcp = &pset->pcp;
1100                 if (pcp->count) {
1101                         free_pcppages_bulk(zone, pcp->count, pcp);
1102                         pcp->count = 0;
1103                 }
1104                 local_irq_restore(flags);
1105         }
1106 }
1107 
1108 /*
1109  * Spill all of this CPU's per-cpu pages back into the buddy allocator.
1110  */
1111 void drain_local_pages(void *arg)
1112 {
1113         drain_pages(smp_processor_id());
1114 }
1115 
1116 /*
1117  * Spill all the per-cpu pages from all CPUs back into the buddy allocator
1118  */
1119 void drain_all_pages(void)
1120 {
1121         on_each_cpu(drain_local_pages, NULL, 1);
1122 }
1123 
1124 #ifdef CONFIG_HIBERNATION
1125 
1126 void mark_free_pages(struct zone *zone)
1127 {
1128         unsigned long pfn, max_zone_pfn;
1129         unsigned long flags;
1130         int order, t;
1131         struct list_head *curr;
1132 
1133         if (!zone->spanned_pages)
1134                 return;
1135 
1136         spin_lock_irqsave(&zone->lock, flags);
1137 
1138         max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1139         for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1140                 if (pfn_valid(pfn)) {
1141                         struct page *page = pfn_to_page(pfn);
1142 
1143                         if (!swsusp_page_is_forbidden(page))
1144                                 swsusp_unset_page_free(page);
1145                 }
1146 
1147         for_each_migratetype_order(order, t) {
1148                 list_for_each(curr, &zone->free_area[order].free_list[t]) {
1149                         unsigned long i;
1150 
1151                         pfn = page_to_pfn(list_entry(curr, struct page, lru));
1152                         for (i = 0; i < (1UL << order); i++)
1153                                 swsusp_set_page_free(pfn_to_page(pfn + i));
1154                 }
1155         }
1156         spin_unlock_irqrestore(&zone->lock, flags);
1157 }
1158 #endif /* CONFIG_PM */
1159 
1160 /*
1161  * Free a 0-order page
1162  * cold == 1 ? free a cold page : free a hot page
1163  */
1164 void free_hot_cold_page(struct page *page, int cold)
1165 {
1166         struct zone *zone = page_zone(page);
1167         struct per_cpu_pages *pcp;
1168         unsigned long flags;
1169         int migratetype;
1170         int wasMlocked = __TestClearPageMlocked(page);
1171 
1172         if (!free_pages_prepare(page, 0))
1173                 return;
1174 
1175         migratetype = get_pageblock_migratetype(page);
1176         set_page_private(page, migratetype);
1177         local_irq_save(flags);
1178         if (unlikely(wasMlocked))
1179                 free_page_mlock(page);
1180         __count_vm_event(PGFREE);
1181 
1182         /*
1183          * We only track unmovable, reclaimable and movable on pcp lists.
1184          * Free ISOLATE pages back to the allocator because they are being
1185          * offlined but treat RESERVE as movable pages so we can get those
1186          * areas back if necessary. Otherwise, we may have to free
1187          * excessively into the page allocator
1188          */
1189         if (migratetype >= MIGRATE_PCPTYPES) {
1190                 if (unlikely(migratetype == MIGRATE_ISOLATE)) {
1191                         free_one_page(zone, page, 0, migratetype);
1192                         goto out;
1193                 }
1194                 migratetype = MIGRATE_MOVABLE;
1195         }
1196 
1197         pcp = &this_cpu_ptr(zone->pageset)->pcp;
1198         if (cold)
1199                 list_add_tail(&page->lru, &pcp->lists[migratetype]);
1200         else
1201                 list_add(&page->lru, &pcp->lists[migratetype]);
1202         pcp->count++;
1203         if (pcp->count >= pcp->high) {
1204                 free_pcppages_bulk(zone, pcp->batch, pcp);
1205                 pcp->count -= pcp->batch;
1206         }
1207 
1208 out:
1209         local_irq_restore(flags);
1210 }
1211 
1212 /*
1213  * split_page takes a non-compound higher-order page, and splits it into
1214  * n (1<<order) sub-pages: page[0..n]
1215  * Each sub-page must be freed individually.
1216  *
1217  * Note: this is probably too low level an operation for use in drivers.
1218  * Please consult with lkml before using this in your driver.
1219  */
1220 void split_page(struct page *page, unsigned int order)
1221 {
1222         int i;
1223 
1224         VM_BUG_ON(PageCompound(page));
1225         VM_BUG_ON(!page_count(page));
1226 
1227 #ifdef CONFIG_KMEMCHECK
1228         /*
1229          * Split shadow pages too, because free(page[0]) would
1230          * otherwise free the whole shadow.
1231          */
1232         if (kmemcheck_page_is_tracked(page))
1233                 split_page(virt_to_page(page[0].shadow), order);
1234 #endif
1235 
1236         for (i = 1; i < (1 << order); i++)
1237                 set_page_refcounted(page + i);
1238 }
1239 
1240 /*
1241  * Similar to split_page except the page is already free. As this is only
1242  * being used for migration, the migratetype of the block also changes.
1243  * As this is called with interrupts disabled, the caller is responsible
1244  * for calling arch_alloc_page() and kernel_map_page() after interrupts
1245  * are enabled.
1246  *
1247  * Note: this is probably too low level an operation for use in drivers.
1248  * Please consult with lkml before using this in your driver.
1249  */
1250 int split_free_page(struct page *page)
1251 {
1252         unsigned int order;
1253         unsigned long watermark;
1254         struct zone *zone;
1255 
1256         BUG_ON(!PageBuddy(page));
1257 
1258         zone = page_zone(page);
1259         order = page_order(page);
1260 
1261         /* Obey watermarks as if the page was being allocated */
1262         watermark = low_wmark_pages(zone) + (1 << order);
1263         if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
1264                 return 0;
1265 
1266         /* Remove page from free list */
1267         list_del(&page->lru);
1268         zone->free_area[order].nr_free--;
1269         rmv_page_order(page);
1270         __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order));
1271 
1272         /* Split into individual pages */
1273         set_page_refcounted(page);
1274         split_page(page, order);
1275 
1276         if (order >= pageblock_order - 1) {
1277                 struct page *endpage = page + (1 << order) - 1;
1278                 for (; page < endpage; page += pageblock_nr_pages)
1279                         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
1280         }
1281 
1282         return 1 << order;
1283 }
1284 
1285 /*
1286  * Really, prep_compound_page() should be called from __rmqueue_bulk().  But
1287  * we cheat by calling it from here, in the order > 0 path.  Saves a branch
1288  * or two.
1289  */
1290 static inline
1291 struct page *buffered_rmqueue(struct zone *preferred_zone,
1292                         struct zone *zone, int order, gfp_t gfp_flags,
1293                         int migratetype)
1294 {
1295         unsigned long flags;
1296         struct page *page;
1297         int cold = !!(gfp_flags & __GFP_COLD);
1298 
1299 again:
1300         if (likely(order == 0)) {
1301                 struct per_cpu_pages *pcp;
1302                 struct list_head *list;
1303 
1304                 local_irq_save(flags);
1305                 pcp = &this_cpu_ptr(zone->pageset)->pcp;
1306                 list = &pcp->lists[migratetype];
1307                 if (list_empty(list)) {
1308                         pcp->count += rmqueue_bulk(zone, 0,
1309                                         pcp->batch, list,
1310                                         migratetype, cold);
1311                         if (unlikely(list_empty(list)))
1312                                 goto failed;
1313                 }
1314 
1315                 if (cold)
1316                         page = list_entry(list->prev, struct page, lru);
1317                 else
1318                         page = list_entry(list->next, struct page, lru);
1319 
1320                 list_del(&page->lru);
1321                 pcp->count--;
1322         } else {
1323                 if (unlikely(gfp_flags & __GFP_NOFAIL)) {
1324                         /*
1325                          * __GFP_NOFAIL is not to be used in new code.
1326                          *
1327                          * All __GFP_NOFAIL callers should be fixed so that they
1328                          * properly detect and handle allocation failures.
1329                          *
1330                          * We most definitely don't want callers attempting to
1331                          * allocate greater than order-1 page units with
1332                          * __GFP_NOFAIL.
1333                          */
1334                         WARN_ON_ONCE(order > 1);
1335                 }
1336                 spin_lock_irqsave(&zone->lock, flags);
1337                 page = __rmqueue(zone, order, migratetype);
1338                 spin_unlock(&zone->lock);
1339                 if (!page)
1340                         goto failed;
1341                 __mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
1342         }
1343 
1344         __count_zone_vm_events(PGALLOC, zone, 1 << order);
1345         zone_statistics(preferred_zone, zone, gfp_flags);
1346         local_irq_restore(flags);
1347 
1348         VM_BUG_ON(bad_range(zone, page));
1349         if (prep_new_page(page, order, gfp_flags))
1350                 goto again;
1351         return page;
1352 
1353 failed:
1354         local_irq_restore(flags);
1355         return NULL;
1356 }
1357 
1358 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
1359 #define ALLOC_WMARK_MIN         WMARK_MIN
1360 #define ALLOC_WMARK_LOW         WMARK_LOW
1361 #define ALLOC_WMARK_HIGH        WMARK_HIGH
1362 #define ALLOC_NO_WATERMARKS     0x04 /* don't check watermarks at all */
1363 
1364 /* Mask to get the watermark bits */
1365 #define ALLOC_WMARK_MASK        (ALLOC_NO_WATERMARKS-1)
1366 
1367 #define ALLOC_HARDER            0x10 /* try to alloc harder */
1368 #define ALLOC_HIGH              0x20 /* __GFP_HIGH set */
1369 #define ALLOC_CPUSET            0x40 /* check for correct cpuset */
1370 
1371 #ifdef CONFIG_FAIL_PAGE_ALLOC
1372 
1373 static struct fail_page_alloc_attr {
1374         struct fault_attr attr;
1375 
1376         u32 ignore_gfp_highmem;
1377         u32 ignore_gfp_wait;
1378         u32 min_order;
1379 
1380 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1381 
1382         struct dentry *ignore_gfp_highmem_file;
1383         struct dentry *ignore_gfp_wait_file;
1384         struct dentry *min_order_file;
1385 
1386 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1387 
1388 } fail_page_alloc = {
1389         .attr = FAULT_ATTR_INITIALIZER,
1390         .ignore_gfp_wait = 1,
1391         .ignore_gfp_highmem = 1,
1392         .min_order = 1,
1393 };
1394 
1395 static int __init setup_fail_page_alloc(char *str)
1396 {
1397         return setup_fault_attr(&fail_page_alloc.attr, str);
1398 }
1399 __setup("fail_page_alloc=", setup_fail_page_alloc);
1400 
1401 static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1402 {
1403         if (order < fail_page_alloc.min_order)
1404                 return 0;
1405         if (gfp_mask & __GFP_NOFAIL)
1406                 return 0;
1407         if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
1408                 return 0;
1409         if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
1410                 return 0;
1411 
1412         return should_fail(&fail_page_alloc.attr, 1 << order);
1413 }
1414 
1415 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
1416 
1417 static int __init fail_page_alloc_debugfs(void)
1418 {
1419         mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
1420         struct dentry *dir;
1421         int err;
1422 
1423         err = init_fault_attr_dentries(&fail_page_alloc.attr,
1424                                        "fail_page_alloc");
1425         if (err)
1426                 return err;
1427         dir = fail_page_alloc.attr.dentries.dir;
1428 
1429         fail_page_alloc.ignore_gfp_wait_file =
1430                 debugfs_create_bool("ignore-gfp-wait", mode, dir,
1431                                       &fail_page_alloc.ignore_gfp_wait);
1432 
1433         fail_page_alloc.ignore_gfp_highmem_file =
1434                 debugfs_create_bool("ignore-gfp-highmem", mode, dir,
1435                                       &fail_page_alloc.ignore_gfp_highmem);
1436         fail_page_alloc.min_order_file =
1437                 debugfs_create_u32("min-order", mode, dir,
1438                                    &fail_page_alloc.min_order);
1439 
1440         if (!fail_page_alloc.ignore_gfp_wait_file ||
1441             !fail_page_alloc.ignore_gfp_highmem_file ||
1442             !fail_page_alloc.min_order_file) {
1443                 err = -ENOMEM;
1444                 debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
1445                 debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
1446                 debugfs_remove(fail_page_alloc.min_order_file);
1447                 cleanup_fault_attr_dentries(&fail_page_alloc.attr);
1448         }
1449 
1450         return err;
1451 }
1452 
1453 late_initcall(fail_page_alloc_debugfs);
1454 
1455 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
1456 
1457 #else /* CONFIG_FAIL_PAGE_ALLOC */
1458 
1459 static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
1460 {
1461         return 0;
1462 }
1463 
1464 #endif /* CONFIG_FAIL_PAGE_ALLOC */
1465 
1466 /*
1467  * Return true if free pages are above 'mark'. This takes into account the order
1468  * of the allocation.
1469  */
1470 static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1471                       int classzone_idx, int alloc_flags, long free_pages)
1472 {
1473         /* free_pages my go negative - that's OK */
1474         long min = mark;
1475         int o;
1476 
1477         free_pages -= (1 << order) + 1;
1478         if (alloc_flags & ALLOC_HIGH)
1479                 min -= min / 2;
1480         if (alloc_flags & ALLOC_HARDER)
1481                 min -= min / 4;
1482 
1483         if (free_pages <= min + z->lowmem_reserve[classzone_idx])
1484                 return false;
1485         for (o = 0; o < order; o++) {
1486                 /* At the next order, this order's pages become unavailable */
1487                 free_pages -= z->free_area[o].nr_free << o;
1488 
1489                 /* Require fewer higher order pages to be free */
1490                 min >>= 1;
1491 
1492                 if (free_pages <= min)
1493                         return false;
1494         }
1495         return true;
1496 }
1497 
1498 bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
1499                       int classzone_idx, int alloc_flags)
1500 {
1501         return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1502                                         zone_page_state(z, NR_FREE_PAGES));
1503 }
1504 
1505 bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark,
1506                       int classzone_idx, int alloc_flags)
1507 {
1508         long free_pages = zone_page_state(z, NR_FREE_PAGES);
1509 
1510         if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
1511                 free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
1512 
1513         return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
1514                                                                 free_pages);
1515 }
1516 
1517 #ifdef CONFIG_NUMA
1518 /*
1519  * zlc_setup - Setup for "zonelist cache".  Uses cached zone data to
1520  * skip over zones that are not allowed by the cpuset, or that have
1521  * been recently (in last second) found to be nearly full.  See further
1522  * comments in mmzone.h.  Reduces cache footprint of zonelist scans
1523  * that have to skip over a lot of full or unallowed zones.
1524  *
1525  * If the zonelist cache is present in the passed in zonelist, then
1526  * returns a pointer to the allowed node mask (either the current
1527  * tasks mems_allowed, or node_states[N_HIGH_MEMORY].)
1528  *
1529  * If the zonelist cache is not available for this zonelist, does
1530  * nothing and returns NULL.
1531  *
1532  * If the fullzones BITMAP in the zonelist cache is stale (more than
1533  * a second since last zap'd) then we zap it out (clear its bits.)
1534  *
1535  * We hold off even calling zlc_setup, until after we've checked the
1536  * first zone in the zonelist, on the theory that most allocations will
1537  * be satisfied from that first zone, so best to examine that zone as
1538  * quickly as we can.
1539  */
1540 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1541 {
1542         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1543         nodemask_t *allowednodes;       /* zonelist_cache approximation */
1544 
1545         zlc = zonelist->zlcache_ptr;
1546         if (!zlc)
1547                 return NULL;
1548 
1549         if (time_after(jiffies, zlc->last_full_zap + HZ)) {
1550                 bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1551                 zlc->last_full_zap = jiffies;
1552         }
1553 
1554         allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
1555                                         &cpuset_current_mems_allowed :
1556                                         &node_states[N_HIGH_MEMORY];
1557         return allowednodes;
1558 }
1559 
1560 /*
1561  * Given 'z' scanning a zonelist, run a couple of quick checks to see
1562  * if it is worth looking at further for free memory:
1563  *  1) Check that the zone isn't thought to be full (doesn't have its
1564  *     bit set in the zonelist_cache fullzones BITMAP).
1565  *  2) Check that the zones node (obtained from the zonelist_cache
1566  *     z_to_n[] mapping) is allowed in the passed in allowednodes mask.
1567  * Return true (non-zero) if zone is worth looking at further, or
1568  * else return false (zero) if it is not.
1569  *
1570  * This check -ignores- the distinction between various watermarks,
1571  * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ...  If a zone is
1572  * found to be full for any variation of these watermarks, it will
1573  * be considered full for up to one second by all requests, unless
1574  * we are so low on memory on all allowed nodes that we are forced
1575  * into the second scan of the zonelist.
1576  *
1577  * In the second scan we ignore this zonelist cache and exactly
1578  * apply the watermarks to all zones, even it is slower to do so.
1579  * We are low on memory in the second scan, and should leave no stone
1580  * unturned looking for a free page.
1581  */
1582 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1583                                                 nodemask_t *allowednodes)
1584 {
1585         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1586         int i;                          /* index of *z in zonelist zones */
1587         int n;                          /* node that zone *z is on */
1588 
1589         zlc = zonelist->zlcache_ptr;
1590         if (!zlc)
1591                 return 1;
1592 
1593         i = z - zonelist->_zonerefs;
1594         n = zlc->z_to_n[i];
1595 
1596         /* This zone is worth trying if it is allowed but not full */
1597         return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
1598 }
1599 
1600 /*
1601  * Given 'z' scanning a zonelist, set the corresponding bit in
1602  * zlc->fullzones, so that subsequent attempts to allocate a page
1603  * from that zone don't waste time re-examining it.
1604  */
1605 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1606 {
1607         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1608         int i;                          /* index of *z in zonelist zones */
1609 
1610         zlc = zonelist->zlcache_ptr;
1611         if (!zlc)
1612                 return;
1613 
1614         i = z - zonelist->_zonerefs;
1615 
1616         set_bit(i, zlc->fullzones);
1617 }
1618 
1619 /*
1620  * clear all zones full, called after direct reclaim makes progress so that
1621  * a zone that was recently full is not skipped over for up to a second
1622  */
1623 static void zlc_clear_zones_full(struct zonelist *zonelist)
1624 {
1625         struct zonelist_cache *zlc;     /* cached zonelist speedup info */
1626 
1627         zlc = zonelist->zlcache_ptr;
1628         if (!zlc)
1629                 return;
1630 
1631         bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
1632 }
1633 
1634 #else   /* CONFIG_NUMA */
1635 
1636 static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
1637 {
1638         return NULL;
1639 }
1640 
1641 static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z,
1642                                 nodemask_t *allowednodes)
1643 {
1644         return 1;
1645 }
1646 
1647 static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z)
1648 {
1649 }
1650 
1651 static void zlc_clear_zones_full(struct zonelist *zonelist)
1652 {
1653 }
1654 #endif  /* CONFIG_NUMA */
1655 
1656 /*
1657  * get_page_from_freelist goes through the zonelist trying to allocate
1658  * a page.
1659  */
1660 static struct page *
1661 get_page_from_freelist(gfp_t gfp_mask, nodemask_t *nodemask, unsigned int order,
1662                 struct zonelist *zonelist, int high_zoneidx, int alloc_flags,
1663                 struct zone *preferred_zone, int migratetype)
1664 {
1665         struct zoneref *z;
1666         struct page *page = NULL;
1667         int classzone_idx;
1668         struct zone *zone;
1669         nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
1670         int zlc_active = 0;             /* set if using zonelist_cache */
1671         int did_zlc_setup = 0;          /* just call zlc_setup() one time */
1672 
1673         classzone_idx = zone_idx(preferred_zone);
1674 zonelist_scan:
1675         /*
1676          * Scan zonelist, looking for a zone with enough free.
1677          * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
1678          */
1679         for_each_zone_zonelist_nodemask(zone, z, zonelist,
1680                                                 high_zoneidx, nodemask) {
1681                 if (NUMA_BUILD && zlc_active &&
1682                         !zlc_zone_worth_trying(zonelist, z, allowednodes))
1683                                 continue;
1684                 if ((alloc_flags & ALLOC_CPUSET) &&
1685                         !cpuset_zone_allowed_softwall(zone, gfp_mask))
1686                                 continue;
1687 
1688                 BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
1689                 if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
1690                         unsigned long mark;
1691                         int ret;
1692 
1693                         mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
1694                         if (zone_watermark_ok(zone, order, mark,
1695                                     classzone_idx, alloc_flags))
1696                                 goto try_this_zone;
1697 
1698                         if (NUMA_BUILD && !did_zlc_setup && nr_online_nodes > 1) {
1699                                 /*
1700                                  * we do zlc_setup if there are multiple nodes
1701                                  * and before considering the first zone allowed
1702                                  * by the cpuset.
1703                                  */
1704                                 allowednodes = zlc_setup(zonelist, alloc_flags);
1705                                 zlc_active = 1;
1706                                 did_zlc_setup = 1;
1707                         }
1708 
1709                         if (zone_reclaim_mode == 0)
1710                                 goto this_zone_full;
1711 
1712                         /*
1713                          * As we may have just activated ZLC, check if the first
1714                          * eligible zone has failed zone_reclaim recently.
1715                          */
1716                         if (NUMA_BUILD && zlc_active &&
1717                                 !zlc_zone_worth_trying(zonelist, z, allowednodes))
1718                                 continue;
1719 
1720                         ret = zone_reclaim(zone, gfp_mask, order);
1721                         switch (ret) {
1722                         case ZONE_RECLAIM_NOSCAN:
1723                                 /* did not scan */
1724                                 continue;
1725                         case ZONE_RECLAIM_FULL:
1726                                 /* scanned but unreclaimable */
1727                                 continue;
1728                         default:
1729                                 /* did we reclaim enough */
1730                                 if (!zone_watermark_ok(zone, order, mark,
1731                                                 classzone_idx, alloc_flags))
1732                                         goto this_zone_full;
1733                         }
1734                 }
1735 
1736 try_this_zone:
1737                 page = buffered_rmqueue(preferred_zone, zone, order,
1738                                                 gfp_mask, migratetype);
1739                 if (page)
1740                         break;
1741 this_zone_full:
1742                 if (NUMA_BUILD)
1743                         zlc_mark_zone_full(zonelist, z);
1744         }
1745 
1746         if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
1747                 /* Disable zlc cache for second zonelist scan */
1748                 zlc_active = 0;
1749                 goto zonelist_scan;
1750         }
1751         return page;
1752 }
1753 
1754 /*
1755  * Large machines with many possible nodes should not always dump per-node
1756  * meminfo in irq context.
1757  */
1758 static inline bool should_suppress_show_mem(void)
1759 {
1760         bool ret = false;
1761 
1762 #if NODES_SHIFT > 8
1763         ret = in_interrupt();
1764 #endif
1765         return ret;
1766 }
1767 
1768 static DEFINE_RATELIMIT_STATE(nopage_rs,
1769                 DEFAULT_RATELIMIT_INTERVAL,
1770                 DEFAULT_RATELIMIT_BURST);
1771 
1772 void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...)
1773 {
1774         va_list args;
1775         unsigned int filter = SHOW_MEM_FILTER_NODES;
1776 
1777         if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs))
1778                 return;
1779 
1780         /*
1781          * This documents exceptions given to allocations in certain
1782          * contexts that are allowed to allocate outside current's set
1783          * of allowed nodes.
1784          */
1785         if (!(gfp_mask & __GFP_NOMEMALLOC))
1786                 if (test_thread_flag(TIF_MEMDIE) ||
1787                     (current->flags & (PF_MEMALLOC | PF_EXITING)))
1788                         filter &= ~SHOW_MEM_FILTER_NODES;
1789         if (in_interrupt() || !(gfp_mask & __GFP_WAIT))
1790                 filter &= ~SHOW_MEM_FILTER_NODES;
1791 
1792         if (fmt) {
1793                 printk(KERN_WARNING);
1794                 va_start(args, fmt);
1795                 vprintk(fmt, args);
1796                 va_end(args);
1797         }
1798 
1799         pr_warning("%s: page allocation failure: order:%d, mode:0x%x\n",
1800                    current->comm, order, gfp_mask);
1801 
1802         dump_stack();
1803         if (!should_suppress_show_mem())
1804                 show_mem(filter);
1805 }
1806 
1807 static inline int
1808 should_alloc_retry(gfp_t gfp_mask, unsigned int order,
1809                                 unsigned long pages_reclaimed)
1810 {
1811         /* Do not loop if specifically requested */
1812         if (gfp_mask & __GFP_NORETRY)
1813                 return 0;
1814 
1815         /*
1816          * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
1817          * means __GFP_NOFAIL, but that may not be true in other
1818          * implementations.
1819          */
1820         if (order <= PAGE_ALLOC_COSTLY_ORDER)
1821                 return 1;
1822 
1823         /*
1824          * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
1825          * specified, then we retry until we no longer reclaim any pages
1826          * (above), or we've reclaimed an order of pages at least as
1827          * large as the allocation's order. In both cases, if the
1828          * allocation still fails, we stop retrying.
1829          */
1830         if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
1831                 return 1;
1832 
1833         /*
1834          * Don't let big-order allocations loop unless the caller
1835          * explicitly requests that.
1836          */
1837         if (gfp_mask & __GFP_NOFAIL)
1838                 return 1;
1839 
1840         return 0;
1841 }
1842 
1843 static inline struct page *
1844 __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
1845         struct zonelist *zonelist, enum zone_type high_zoneidx,
1846         nodemask_t *nodemask, struct zone *preferred_zone,
1847         int migratetype)
1848 {
1849         struct page *page;
1850 
1851         /* Acquire the OOM killer lock for the zones in zonelist */
1852         if (!try_set_zonelist_oom(zonelist, gfp_mask)) {
1853                 schedule_timeout_uninterruptible(1);
1854                 return NULL;
1855         }
1856 
1857         /*
1858          * Go through the zonelist yet one more time, keep very high watermark
1859          * here, this is only to catch a parallel oom killing, we must fail if
1860          * we're still under heavy pressure.
1861          */
1862         page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
1863                 order, zonelist, high_zoneidx,
1864                 ALLOC_WMARK_HIGH|ALLOC_CPUSET,
1865                 preferred_zone, migratetype);
1866         if (page)
1867                 goto out;
1868 
1869         if (!(gfp_mask & __GFP_NOFAIL)) {
1870                 /* The OOM killer will not help higher order allocs */
1871                 if (order > PAGE_ALLOC_COSTLY_ORDER)
1872                         goto out;
1873                 /* The OOM killer does not needlessly kill tasks for lowmem */
1874                 if (high_zoneidx < ZONE_NORMAL)
1875                         goto out;
1876                 /*
1877                  * GFP_THISNODE contains __GFP_NORETRY and we never hit this.
1878                  * Sanity check for bare calls of __GFP_THISNODE, not real OOM.
1879                  * The caller should handle page allocation failure by itself if
1880                  * it specifies __GFP_THISNODE.
1881                  * Note: Hugepage uses it but will hit PAGE_ALLOC_COSTLY_ORDER.
1882                  */
1883                 if (gfp_mask & __GFP_THISNODE)
1884                         goto out;
1885         }
1886         /* Exhausted what can be done so it's blamo time */
1887         out_of_memory(zonelist, gfp_mask, order, nodemask);
1888 
1889 out:
1890         clear_zonelist_oom(zonelist, gfp_mask);
1891         return page;
1892 }
1893 
1894 #ifdef CONFIG_COMPACTION
1895 /* Try memory compaction for high-order allocations before reclaim */
1896 static struct page *
1897 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
1898         struct zonelist *zonelist, enum zone_type high_zoneidx,
1899         nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1900         int migratetype, bool sync_migration,
1901         bool *deferred_compaction,
1902         unsigned long *did_some_progress)
1903 {
1904         struct page *page;
1905 
1906         if (!order)
1907                 return NULL;
1908 
1909         if (compaction_deferred(preferred_zone)) {
1910                 *deferred_compaction = true;
1911                 return NULL;
1912         }
1913 
1914         current->flags |= PF_MEMALLOC;
1915         *did_some_progress = try_to_compact_pages(zonelist, order, gfp_mask,
1916                                                 nodemask, sync_migration);
1917         current->flags &= ~PF_MEMALLOC;
1918         if (*did_some_progress != COMPACT_SKIPPED) {
1919 
1920                 /* Page migration frees to the PCP lists but we want merging */
1921                 drain_pages(get_cpu());
1922                 put_cpu();
1923 
1924                 page = get_page_from_freelist(gfp_mask, nodemask,
1925                                 order, zonelist, high_zoneidx,
1926                                 alloc_flags, preferred_zone,
1927                                 migratetype);
1928                 if (page) {
1929                         preferred_zone->compact_considered = 0;
1930                         preferred_zone->compact_defer_shift = 0;
1931                         count_vm_event(COMPACTSUCCESS);
1932                         return page;
1933                 }
1934 
1935                 /*
1936                  * It's bad if compaction run occurs and fails.
1937                  * The most likely reason is that pages exist,
1938                  * but not enough to satisfy watermarks.
1939                  */
1940                 count_vm_event(COMPACTFAIL);
1941 
1942                 /*
1943                  * As async compaction considers a subset of pageblocks, only
1944                  * defer if the failure was a sync compaction failure.
1945                  */
1946                 if (sync_migration)
1947                         defer_compaction(preferred_zone);
1948 
1949                 cond_resched();
1950         }
1951 
1952         return NULL;
1953 }
1954 #else
1955 static inline struct page *
1956 __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
1957         struct zonelist *zonelist, enum zone_type high_zoneidx,
1958         nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1959         int migratetype, bool sync_migration,
1960         bool *deferred_compaction,
1961         unsigned long *did_some_progress)
1962 {
1963         return NULL;
1964 }
1965 #endif /* CONFIG_COMPACTION */
1966 
1967 /* The really slow allocator path where we enter direct reclaim */
1968 static inline struct page *
1969 __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
1970         struct zonelist *zonelist, enum zone_type high_zoneidx,
1971         nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
1972         int migratetype, unsigned long *did_some_progress)
1973 {
1974         struct page *page = NULL;
1975         struct reclaim_state reclaim_state;
1976         bool drained = false;
1977 
1978         cond_resched();
1979 
1980         /* We now go into synchronous reclaim */
1981         cpuset_memory_pressure_bump();
1982         current->flags |= PF_MEMALLOC;
1983         lockdep_set_current_reclaim_state(gfp_mask);
1984         reclaim_state.reclaimed_slab = 0;
1985         current->reclaim_state = &reclaim_state;
1986 
1987         *did_some_progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
1988 
1989         current->reclaim_state = NULL;
1990         lockdep_clear_current_reclaim_state();
1991         current->flags &= ~PF_MEMALLOC;
1992 
1993         cond_resched();
1994 
1995         if (unlikely(!(*did_some_progress)))
1996                 return NULL;
1997 
1998         /* After successful reclaim, reconsider all zones for allocation */
1999         if (NUMA_BUILD)
2000                 zlc_clear_zones_full(zonelist);
2001 
2002 retry:
2003         page = get_page_from_freelist(gfp_mask, nodemask, order,
2004                                         zonelist, high_zoneidx,
2005                                         alloc_flags, preferred_zone,
2006                                         migratetype);
2007 
2008         /*
2009          * If an allocation failed after direct reclaim, it could be because
2010          * pages are pinned on the per-cpu lists. Drain them and try again
2011          */
2012         if (!page && !drained) {
2013                 drain_all_pages();
2014                 drained = true;
2015                 goto retry;
2016         }
2017 
2018         return page;
2019 }
2020 
2021 /*
2022  * This is called in the allocator slow-path if the allocation request is of
2023  * sufficient urgency to ignore watermarks and take other desperate measures
2024  */
2025 static inline struct page *
2026 __alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
2027         struct zonelist *zonelist, enum zone_type high_zoneidx,
2028         nodemask_t *nodemask, struct zone *preferred_zone,
2029         int migratetype)
2030 {
2031         struct page *page;
2032 
2033         do {
2034                 page = get_page_from_freelist(gfp_mask, nodemask, order,
2035                         zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
2036                         preferred_zone, migratetype);
2037 
2038                 if (!page && gfp_mask & __GFP_NOFAIL)
2039                         wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2040         } while (!page && (gfp_mask & __GFP_NOFAIL));
2041 
2042         return page;
2043 }
2044 
2045 static inline
2046 void wake_all_kswapd(unsigned int order, struct zonelist *zonelist,
2047                                                 enum zone_type high_zoneidx,
2048                                                 enum zone_type classzone_idx)
2049 {
2050         struct zoneref *z;
2051         struct zone *zone;
2052 
2053         for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
2054                 wakeup_kswapd(zone, order, classzone_idx);
2055 }
2056 
2057 static inline int
2058 gfp_to_alloc_flags(gfp_t gfp_mask)
2059 {
2060         int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
2061         const gfp_t wait = gfp_mask & __GFP_WAIT;
2062 
2063         /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
2064         BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
2065 
2066         /*
2067          * The caller may dip into page reserves a bit more if the caller
2068          * cannot run direct reclaim, or if the caller has realtime scheduling
2069          * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
2070          * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
2071          */
2072         alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
2073 
2074         if (!wait) {
2075                 /*
2076                  * Not worth trying to allocate harder for
2077                  * __GFP_NOMEMALLOC even if it can't schedule.
2078                  */
2079                 if  (!(gfp_mask & __GFP_NOMEMALLOC))
2080                         alloc_flags |= ALLOC_HARDER;
2081                 /*
2082                  * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
2083                  * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
2084                  */
2085                 alloc_flags &= ~ALLOC_CPUSET;
2086         } else if (unlikely(rt_task(current)) && !in_interrupt())
2087                 alloc_flags |= ALLOC_HARDER;
2088 
2089         if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
2090                 if (!in_interrupt() &&
2091                     ((current->flags & PF_MEMALLOC) ||
2092                      unlikely(test_thread_flag(TIF_MEMDIE))))
2093                         alloc_flags |= ALLOC_NO_WATERMARKS;
2094         }
2095 
2096         return alloc_flags;
2097 }
2098 
2099 static inline struct page *
2100 __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
2101         struct zonelist *zonelist, enum zone_type high_zoneidx,
2102         nodemask_t *nodemask, struct zone *preferred_zone,
2103         int migratetype)
2104 {
2105         const gfp_t wait = gfp_mask & __GFP_WAIT;
2106         struct page *page = NULL;
2107         int alloc_flags;
2108         unsigned long pages_reclaimed = 0;
2109         unsigned long did_some_progress;
2110         bool sync_migration = false;
2111         bool deferred_compaction = false;
2112 
2113         /*
2114          * In the slowpath, we sanity check order to avoid ever trying to
2115          * reclaim >= MAX_ORDER areas which will never succeed. Callers may
2116          * be using allocators in order of preference for an area that is
2117          * too large.
2118          */
2119         if (order >= MAX_ORDER) {
2120                 WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
2121                 return NULL;
2122         }
2123 
2124         /*
2125          * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
2126          * __GFP_NOWARN set) should not cause reclaim since the subsystem
2127          * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
2128          * using a larger set of nodes after it has established that the
2129          * allowed per node queues are empty and that nodes are
2130          * over allocated.
2131          */
2132         if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
2133                 goto nopage;
2134 
2135 restart:
2136         if (!(gfp_mask & __GFP_NO_KSWAPD))
2137                 wake_all_kswapd(order, zonelist, high_zoneidx,
2138                                                 zone_idx(preferred_zone));
2139 
2140         /*
2141          * OK, we're below the kswapd watermark and have kicked background
2142          * reclaim. Now things get more complex, so set up alloc_flags according
2143          * to how we want to proceed.
2144          */
2145         alloc_flags = gfp_to_alloc_flags(gfp_mask);
2146 
2147         /*
2148          * Find the true preferred zone if the allocation is unconstrained by
2149          * cpusets.
2150          */
2151         if (!(alloc_flags & ALLOC_CPUSET) && !nodemask)
2152                 first_zones_zonelist(zonelist, high_zoneidx, NULL,
2153                                         &preferred_zone);
2154 
2155 rebalance:
2156         /* This is the last chance, in general, before the goto nopage. */
2157         page = get_page_from_freelist(gfp_mask, nodemask, order, zonelist,
2158                         high_zoneidx, alloc_flags & ~ALLOC_NO_WATERMARKS,
2159                         preferred_zone, migratetype);
2160         if (page)
2161                 goto got_pg;
2162 
2163         /* Allocate without watermarks if the context allows */
2164         if (alloc_flags & ALLOC_NO_WATERMARKS) {
2165                 page = __alloc_pages_high_priority(gfp_mask, order,
2166                                 zonelist, high_zoneidx, nodemask,
2167                                 preferred_zone, migratetype);
2168                 if (page)
2169                         goto got_pg;
2170         }
2171 
2172         /* Atomic allocations - we can't balance anything */
2173         if (!wait)
2174                 goto nopage;
2175 
2176         /* Avoid recursion of direct reclaim */
2177         if (current->flags & PF_MEMALLOC)
2178                 goto nopage;
2179 
2180         /* Avoid allocations with no watermarks from looping endlessly */
2181         if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
2182                 goto nopage;
2183 
2184         /*
2185          * Try direct compaction. The first pass is asynchronous. Subsequent
2186          * attempts after direct reclaim are synchronous
2187          */
2188         page = __alloc_pages_direct_compact(gfp_mask, order,
2189                                         zonelist, high_zoneidx,
2190                                         nodemask,
2191                                         alloc_flags, preferred_zone,
2192                                         migratetype, sync_migration,
2193                                         &deferred_compaction,
2194                                         &did_some_progress);
2195         if (page)
2196                 goto got_pg;
2197         sync_migration = true;
2198 
2199         /*
2200          * If compaction is deferred for high-order allocations, it is because
2201          * sync compaction recently failed. In this is the case and the caller
2202          * has requested the system not be heavily disrupted, fail the
2203          * allocation now instead of entering direct reclaim
2204          */
2205         if (deferred_compaction && (gfp_mask & __GFP_NO_KSWAPD))
2206                 goto nopage;
2207 
2208         /* Try direct reclaim and then allocating */
2209         page = __alloc_pages_direct_reclaim(gfp_mask, order,
2210                                         zonelist, high_zoneidx,
2211                                         nodemask,
2212                                         alloc_flags, preferred_zone,
2213                                         migratetype, &did_some_progress);
2214         if (page)
2215                 goto got_pg;
2216 
2217         /*
2218          * If we failed to make any progress reclaiming, then we are
2219          * running out of options and have to consider going OOM
2220          */
2221         if (!did_some_progress) {
2222                 if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
2223                         if (oom_killer_disabled)
2224                                 goto nopage;
2225                         page = __alloc_pages_may_oom(gfp_mask, order,
2226                                         zonelist, high_zoneidx,
2227                                         nodemask, preferred_zone,
2228                                         migratetype);
2229                         if (page)
2230                                 goto got_pg;
2231 
2232                         if (!(gfp_mask & __GFP_NOFAIL)) {
2233                                 /*
2234                                  * The oom killer is not called for high-order
2235                                  * allocations that may fail, so if no progress
2236                                  * is being made, there are no other options and
2237                                  * retrying is unlikely to help.
2238                                  */
2239                                 if (order > PAGE_ALLOC_COSTLY_ORDER)
2240                                         goto nopage;
2241                                 /*
2242                                  * The oom killer is not called for lowmem
2243                                  * allocations to prevent needlessly killing
2244                                  * innocent tasks.
2245                                  */
2246                                 if (high_zoneidx < ZONE_NORMAL)
2247                                         goto nopage;
2248                         }
2249 
2250                         goto restart;
2251                 }
2252         }
2253 
2254         /* Check if we should retry the allocation */
2255         pages_reclaimed += did_some_progress;
2256         if (should_alloc_retry(gfp_mask, order, pages_reclaimed)) {
2257                 /* Wait for some write requests to complete then retry */
2258                 wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
2259                 goto rebalance;
2260         } else {
2261                 /*
2262                  * High-order allocations do not necessarily loop after
2263                  * direct reclaim and reclaim/compaction depends on compaction
2264                  * being called after reclaim so call directly if necessary
2265                  */
2266                 page = __alloc_pages_direct_compact(gfp_mask, order,
2267                                         zonelist, high_zoneidx,
2268                                         nodemask,
2269                                         alloc_flags, preferred_zone,
2270                                         migratetype, sync_migration,
2271                                         &deferred_compaction,
2272                                         &did_some_progress);
2273                 if (page)
2274                         goto got_pg;
2275         }
2276 
2277 nopage:
2278         warn_alloc_failed(gfp_mask, order, NULL);
2279         return page;
2280 got_pg:
2281         if (kmemcheck_enabled)
2282                 kmemcheck_pagealloc_alloc(page, order, gfp_mask);
2283         return page;
2284 
2285 }
2286 
2287 /*
2288  * This is the 'heart' of the zoned buddy allocator.
2289  */
2290 struct page *
2291 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
2292                         struct zonelist *zonelist, nodemask_t *nodemask)
2293 {
2294         enum zone_type high_zoneidx = gfp_zone(gfp_mask);
2295         struct zone *preferred_zone;
2296         struct page *page = NULL;
2297         int migratetype = allocflags_to_migratetype(gfp_mask);
2298         unsigned int cpuset_mems_cookie;
2299 
2300         gfp_mask &= gfp_allowed_mask;
2301 
2302         lockdep_trace_alloc(gfp_mask);
2303 
2304         might_sleep_if(gfp_mask & __GFP_WAIT);
2305 
2306         if (should_fail_alloc_page(gfp_mask, order))
2307                 return NULL;
2308 
2309         /*
2310          * Check the zones suitable for the gfp_mask contain at least one
2311          * valid zone. It's possible to have an empty zonelist as a result
2312          * of GFP_THISNODE and a memoryless node
2313          */
2314         if (unlikely(!zonelist->_zonerefs->zone))
2315                 return NULL;
2316 
2317 retry_cpuset:
2318         cpuset_mems_cookie = get_mems_allowed();
2319 
2320         /* The preferred zone is used for statistics later */
2321         first_zones_zonelist(zonelist, high_zoneidx,
2322                                 nodemask ? : &cpuset_current_mems_allowed,
2323                                 &preferred_zone);
2324         if (!preferred_zone)
2325                 goto out;
2326 
2327         /* First allocation attempt */
2328         page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
2329                         zonelist, high_zoneidx, ALLOC_WMARK_LOW|ALLOC_CPUSET,
2330                         preferred_zone, migratetype);
2331         if (unlikely(!page))
2332                 page = __alloc_pages_slowpath(gfp_mask, order,
2333                                 zonelist, high_zoneidx, nodemask,
2334                                 preferred_zone, migratetype);
2335 
2336         trace_mm_page_alloc(page, order, gfp_mask, migratetype);
2337 
2338 out:
2339         /*
2340          * When updating a task's mems_allowed, it is possible to race with
2341          * parallel threads in such a way that an allocation can fail while
2342          * the mask is being updated. If a page allocation is about to fail,
2343          * check if the cpuset changed during allocation and if so, retry.
2344          */
2345         if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
2346                 goto retry_cpuset;
2347 
2348         return page;
2349 }
2350 EXPORT_SYMBOL(__alloc_pages_nodemask);
2351 
2352 /*
2353  * Common helper functions.
2354  */
2355 unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
2356 {
2357         struct page *page;
2358 
2359         /*
2360          * __get_free_pages() returns a 32-bit address, which cannot represent
2361          * a highmem page
2362          */
2363         VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
2364 
2365         page = alloc_pages(gfp_mask, order);
2366         if (!page)
2367                 return 0;
2368         return (unsigned long) page_address(page);
2369 }
2370 EXPORT_SYMBOL(__get_free_pages);
2371 
2372 unsigned long get_zeroed_page(gfp_t gfp_mask)
2373 {
2374         return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
2375 }
2376 EXPORT_SYMBOL(get_zeroed_page);
2377 
2378 void __pagevec_free(struct pagevec *pvec)
2379 {
2380         int i = pagevec_count(pvec);
2381 
2382         while (--i >= 0) {
2383                 trace_mm_pagevec_free(pvec->pages[i], pvec->cold);
2384                 free_hot_cold_page(pvec->pages[i], pvec->cold);
2385         }
2386 }
2387 
2388 void __free_pages(struct page *page, unsigned int order)
2389 {
2390         if (put_page_testzero(page)) {
2391                 if (order == 0)
2392                         free_hot_cold_page(page, 0);
2393                 else
2394                         __free_pages_ok(page, order);
2395         }
2396 }
2397 
2398 EXPORT_SYMBOL(__free_pages);
2399 
2400 void free_pages(unsigned long addr, unsigned int order)
2401 {
2402         if (addr != 0) {
2403                 VM_BUG_ON(!virt_addr_valid((void *)addr));
2404                 __free_pages(virt_to_page((void *)addr), order);
2405         }
2406 }
2407 
2408 EXPORT_SYMBOL(free_pages);
2409 
2410 static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
2411 {
2412         if (addr) {
2413                 unsigned long alloc_end = addr + (PAGE_SIZE << order);
2414                 unsigned long used = addr + PAGE_ALIGN(size);
2415 
2416                 split_page(virt_to_page((void *)addr), order);
2417                 while (used < alloc_end) {
2418                         free_page(used);
2419                         used += PAGE_SIZE;
2420                 }
2421         }
2422         return (void *)addr;
2423 }
2424 
2425 /**
2426  * alloc_pages_exact - allocate an exact number physically-contiguous pages.
2427  * @size: the number of bytes to allocate
2428  * @gfp_mask: GFP flags for the allocation
2429  *
2430  * This function is similar to alloc_pages(), except that it allocates the
2431  * minimum number of pages to satisfy the request.  alloc_pages() can only
2432  * allocate memory in power-of-two pages.
2433  *
2434  * This function is also limited by MAX_ORDER.
2435  *
2436  * Memory allocated by this function must be released by free_pages_exact().
2437  */
2438 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
2439 {
2440         unsigned int order = get_order(size);
2441         unsigned long addr;
2442 
2443         addr = __get_free_pages(gfp_mask, order);
2444         return make_alloc_exact(addr, order, size);
2445 }
2446 EXPORT_SYMBOL(alloc_pages_exact);
2447 
2448 /**
2449  * alloc_pages_exact_nid - allocate an exact number of physically-contiguous
2450  *                         pages on a node.
2451  * @nid: the preferred node ID where memory should be allocated
2452  * @size: the number of bytes to allocate
2453  * @gfp_mask: GFP flags for the allocation
2454  *
2455  * Like alloc_pages_exact(), but try to allocate on node nid first before falling
2456  * back.
2457  * Note this is not alloc_pages_exact_node() which allocates on a specific node,
2458  * but is not exact.
2459  */
2460 void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
2461 {
2462         unsigned order = get_order(size);
2463         struct page *p = alloc_pages_node(nid, gfp_mask, order);
2464         if (!p)
2465                 return NULL;
2466         return make_alloc_exact((unsigned long)page_address(p), order, size);
2467 }
2468 EXPORT_SYMBOL(alloc_pages_exact_nid);
2469 
2470 /**
2471  * free_pages_exact - release memory allocated via alloc_pages_exact()
2472  * @virt: the value returned by alloc_pages_exact.
2473  * @size: size of allocation, same value as passed to alloc_pages_exact().
2474  *
2475  * Release the memory allocated by a previous call to alloc_pages_exact.
2476  */
2477 void free_pages_exact(void *virt, size_t size)
2478 {
2479         unsigned long addr = (unsigned long)virt;
2480         unsigned long end = addr + PAGE_ALIGN(size);
2481 
2482         while (addr < end) {
2483                 free_page(addr);
2484                 addr += PAGE_SIZE;
2485         }
2486 }
2487 EXPORT_SYMBOL(free_pages_exact);
2488 
2489 static unsigned int nr_free_zone_pages(int offset)
2490 {
2491         struct zoneref *z;
2492         struct zone *zone;
2493 
2494         /* Just pick one node, since fallback list is circular */
2495         unsigned int sum = 0;
2496 
2497         struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
2498 
2499         for_each_zone_zonelist(zone, z, zonelist, offset) {
2500                 unsigned long size = zone->present_pages;
2501                 unsigned long high = high_wmark_pages(zone);
2502                 if (size > high)
2503                         sum += size - high;
2504         }
2505 
2506         return sum;
2507 }
2508 
2509 /*
2510  * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
2511  */
2512 unsigned int nr_free_buffer_pages(void)
2513 {
2514         return nr_free_zone_pages(gfp_zone(GFP_USER));
2515 }
2516 EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
2517 
2518 /*
2519  * Amount of free RAM allocatable within all zones
2520  */
2521 unsigned int nr_free_pagecache_pages(void)
2522 {
2523         return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
2524 }
2525 
2526 static inline void show_node(struct zone *zone)
2527 {
2528         if (NUMA_BUILD)
2529                 printk("Node %d ", zone_to_nid(zone));
2530 }
2531 
2532 void si_meminfo(struct sysinfo *val)
2533 {
2534         val->totalram = totalram_pages;
2535         val->sharedram = 0;
2536         val->freeram = global_page_state(NR_FREE_PAGES);
2537         val->bufferram = nr_blockdev_pages();
2538         val->totalhigh = totalhigh_pages;
2539         val->freehigh = nr_free_highpages();
2540         val->mem_unit = PAGE_SIZE;
2541 }
2542 
2543 EXPORT_SYMBOL(si_meminfo);
2544 
2545 #ifdef CONFIG_NUMA
2546 void si_meminfo_node(struct sysinfo *val, int nid)
2547 {
2548         pg_data_t *pgdat = NODE_DATA(nid);
2549 
2550         val->totalram = pgdat->node_present_pages;
2551         val->freeram = node_page_state(nid, NR_FREE_PAGES);
2552 #ifdef CONFIG_HIGHMEM
2553         val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
2554         val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
2555                         NR_FREE_PAGES);
2556 #else
2557         val->totalhigh = 0;
2558         val->freehigh = 0;
2559 #endif
2560         val->mem_unit = PAGE_SIZE;
2561 }
2562 #endif
2563 
2564 /*
2565  * Determine whether the node should be displayed or not, depending on whether
2566  * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
2567  */
2568 bool skip_free_areas_node(unsigned int flags, int nid)
2569 {
2570         bool ret = false;
2571         unsigned int cpuset_mems_cookie;
2572 
2573         if (!(flags & SHOW_MEM_FILTER_NODES))
2574                 goto out;
2575 
2576         do {
2577                 cpuset_mems_cookie = get_mems_allowed();
2578                 ret = !node_isset(nid, cpuset_current_mems_allowed);
2579         } while (!put_mems_allowed(cpuset_mems_cookie));
2580 out:
2581         return ret;
2582 }
2583 
2584 #define K(x) ((x) << (PAGE_SHIFT-10))
2585 
2586 /*
2587  * Show free area list (used inside shift_scroll-lock stuff)
2588  * We also calculate the percentage fragmentation. We do this by counting the
2589  * memory on each free list with the exception of the first item on the list.
2590  * Suppresses nodes that are not allowed by current's cpuset if
2591  * SHOW_MEM_FILTER_NODES is passed.
2592  */
2593 void show_free_areas(unsigned int filter)
2594 {
2595         int cpu;
2596         struct zone *zone;
2597 
2598         for_each_populated_zone(zone) {
2599                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
2600                         continue;
2601                 show_node(zone);
2602                 printk("%s per-cpu:\n", zone->name);
2603 
2604                 for_each_online_cpu(cpu) {
2605                         struct per_cpu_pageset *pageset;
2606 
2607                         pageset = per_cpu_ptr(zone->pageset, cpu);
2608 
2609                         printk("CPU %4d: hi:%5d, btch:%4d usd:%4d\n",
2610                                cpu, pageset->pcp.high,
2611                                pageset->pcp.batch, pageset->pcp.count);
2612                 }
2613         }
2614 
2615         printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
2616                 " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
2617                 " unevictable:%lu"
2618                 " dirty:%lu writeback:%lu unstable:%lu\n"
2619                 " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
2620                 " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n",
2621                 global_page_state(NR_ACTIVE_ANON),
2622                 global_page_state(NR_INACTIVE_ANON),
2623                 global_page_state(NR_ISOLATED_ANON),
2624                 global_page_state(NR_ACTIVE_FILE),
2625                 global_page_state(NR_INACTIVE_FILE),
2626                 global_page_state(NR_ISOLATED_FILE),
2627                 global_page_state(NR_UNEVICTABLE),
2628                 global_page_state(NR_FILE_DIRTY),
2629                 global_page_state(NR_WRITEBACK),
2630                 global_page_state(NR_UNSTABLE_NFS),
2631                 global_page_state(NR_FREE_PAGES),
2632                 global_page_state(NR_SLAB_RECLAIMABLE),
2633                 global_page_state(NR_SLAB_UNRECLAIMABLE),
2634                 global_page_state(NR_FILE_MAPPED),
2635                 global_page_state(NR_SHMEM),
2636                 global_page_state(NR_PAGETABLE),
2637                 global_page_state(NR_BOUNCE));
2638 
2639         for_each_populated_zone(zone) {
2640                 int i;
2641 
2642                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
2643                         continue;
2644                 show_node(zone);
2645                 printk("%s"
2646                         " free:%lukB"
2647                         " min:%lukB"
2648                         " low:%lukB"
2649                         " high:%lukB"
2650                         " active_anon:%lukB"
2651                         " inactive_anon:%lukB"
2652                         " active_file:%lukB"
2653                         " inactive_file:%lukB"
2654                         " unevictable:%lukB"
2655                         " isolated(anon):%lukB"
2656                         " isolated(file):%lukB"
2657                         " present:%lukB"
2658                         " mlocked:%lukB"
2659                         " dirty:%lukB"
2660                         " writeback:%lukB"
2661                         " mapped:%lukB"
2662                         " shmem:%lukB"
2663                         " slab_reclaimable:%lukB"
2664                         " slab_unreclaimable:%lukB"
2665                         " kernel_stack:%lukB"
2666                         " pagetables:%lukB"
2667                         " unstable:%lukB"
2668                         " bounce:%lukB"
2669                         " writeback_tmp:%lukB"
2670                         " pages_scanned:%lu"
2671                         " all_unreclaimable? %s"
2672                         "\n",
2673                         zone->name,
2674                         K(zone_page_state(zone, NR_FREE_PAGES)),
2675                         K(min_wmark_pages(zone)),
2676                         K(low_wmark_pages(zone)),
2677                         K(high_wmark_pages(zone)),
2678                         K(zone_page_state(zone, NR_ACTIVE_ANON)),
2679                         K(zone_page_state(zone, NR_INACTIVE_ANON)),
2680                         K(zone_page_state(zone, NR_ACTIVE_FILE)),
2681                         K(zone_page_state(zone, NR_INACTIVE_FILE)),
2682                         K(zone_page_state(zone, NR_UNEVICTABLE)),
2683                         K(zone_page_state(zone, NR_ISOLATED_ANON)),
2684                         K(zone_page_state(zone, NR_ISOLATED_FILE)),
2685                         K(zone->present_pages),
2686                         K(zone_page_state(zone, NR_MLOCK)),
2687                         K(zone_page_state(zone, NR_FILE_DIRTY)),
2688                         K(zone_page_state(zone, NR_WRITEBACK)),
2689                         K(zone_page_state(zone, NR_FILE_MAPPED)),
2690                         K(zone_page_state(zone, NR_SHMEM)),
2691                         K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
2692                         K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
2693                         zone_page_state(zone, NR_KERNEL_STACK) *
2694                                 THREAD_SIZE / 1024,
2695                         K(zone_page_state(zone, NR_PAGETABLE)),
2696                         K(zone_page_state(zone, NR_UNSTABLE_NFS)),
2697                         K(zone_page_state(zone, NR_BOUNCE)),
2698                         K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
2699                         zone->pages_scanned,
2700                         (zone->all_unreclaimable ? "yes" : "no")
2701                         );
2702                 printk("lowmem_reserve[]:");
2703                 for (i = 0; i < MAX_NR_ZONES; i++)
2704                         printk(" %lu", zone->lowmem_reserve[i]);
2705                 printk("\n");
2706         }
2707 
2708         for_each_populated_zone(zone) {
2709                 unsigned long nr[MAX_ORDER], flags, order, total = 0;
2710 
2711                 if (skip_free_areas_node(filter, zone_to_nid(zone)))
2712                         continue;
2713                 show_node(zone);
2714                 printk("%s: ", zone->name);
2715 
2716                 spin_lock_irqsave(&zone->lock, flags);
2717                 for (order = 0; order < MAX_ORDER; order++) {
2718                         nr[order] = zone->free_area[order].nr_free;
2719                         total += nr[order] << order;
2720                 }
2721                 spin_unlock_irqrestore(&zone->lock, flags);
2722                 for (order = 0; order < MAX_ORDER; order++)
2723                         printk("%lu*%lukB ", nr[order], K(1UL) << order);
2724                 printk("= %lukB\n", K(total));
2725         }
2726 
2727         printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
2728 
2729         show_swap_cache_info();
2730 }
2731 
2732 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
2733 {
2734         zoneref->zone = zone;
2735         zoneref->zone_idx = zone_idx(zone);
2736 }
2737 
2738 /*
2739  * Builds allocation fallback zone lists.
2740  *
2741  * Add all populated zones of a node to the zonelist.
2742  */
2743 static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
2744                                 int nr_zones, enum zone_type zone_type)
2745 {
2746         struct zone *zone;
2747 
2748         BUG_ON(zone_type >= MAX_NR_ZONES);
2749         zone_type++;
2750 
2751         do {
2752                 zone_type--;
2753                 zone = pgdat->node_zones + zone_type;
2754                 if (populated_zone(zone)) {
2755                         zoneref_set_zone(zone,
2756                                 &zonelist->_zonerefs[nr_zones++]);
2757                         check_highest_zone(zone_type);
2758                 }
2759 
2760         } while (zone_type);
2761         return nr_zones;
2762 }
2763 
2764 
2765 /*
2766  *  zonelist_order:
2767  *  0 = automatic detection of better ordering.
2768  *  1 = order by ([node] distance, -zonetype)
2769  *  2 = order by (-zonetype, [node] distance)
2770  *
2771  *  If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
2772  *  the same zonelist. So only NUMA can configure this param.
2773  */
2774 #define ZONELIST_ORDER_DEFAULT  0
2775 #define ZONELIST_ORDER_NODE     1
2776 #define ZONELIST_ORDER_ZONE     2
2777 
2778 /* zonelist order in the kernel.
2779  * set_zonelist_order() will set this to NODE or ZONE.
2780  */
2781 static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
2782 static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
2783 
2784 
2785 #ifdef CONFIG_NUMA
2786 /* The value user specified ....changed by config */
2787 static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2788 /* string for sysctl */
2789 #define NUMA_ZONELIST_ORDER_LEN 16
2790 char numa_zonelist_order[16] = "default";
2791 
2792 /*
2793  * interface for configure zonelist ordering.
2794  * command line option "numa_zonelist_order"
2795  *      = "[dD]efault   - default, automatic configuration.
2796  *      = "[nN]ode      - order by node locality, then by zone within node
2797  *      = "[zZ]one      - order by zone, then by locality within zone
2798  */
2799 
2800 static int __parse_numa_zonelist_order(char *s)
2801 {
2802         if (*s == 'd' || *s == 'D') {
2803                 user_zonelist_order = ZONELIST_ORDER_DEFAULT;
2804         } else if (*s == 'n' || *s == 'N') {
2805                 user_zonelist_order = ZONELIST_ORDER_NODE;
2806         } else if (*s == 'z' || *s == 'Z') {
2807                 user_zonelist_order = ZONELIST_ORDER_ZONE;
2808         } else {
2809                 printk(KERN_WARNING
2810                         "Ignoring invalid numa_zonelist_order value:  "
2811                         "%s\n", s);
2812                 return -EINVAL;
2813         }
2814         return 0;
2815 }
2816 
2817 static __init int setup_numa_zonelist_order(char *s)
2818 {
2819         int ret;
2820 
2821         if (!s)
2822                 return 0;
2823 
2824         ret = __parse_numa_zonelist_order(s);
2825         if (ret == 0)
2826                 strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
2827 
2828         return ret;
2829 }
2830 early_param("numa_zonelist_order", setup_numa_zonelist_order);
2831 
2832 /*
2833  * sysctl handler for numa_zonelist_order
2834  */
2835 int numa_zonelist_order_handler(ctl_table *table, int write,
2836                 void __user *buffer, size_t *length,
2837                 loff_t *ppos)
2838 {
2839         char saved_string[NUMA_ZONELIST_ORDER_LEN];
2840         int ret;
2841         static DEFINE_MUTEX(zl_order_mutex);
2842 
2843         mutex_lock(&zl_order_mutex);
2844         if (write)
2845                 strcpy(saved_string, (char*)table->data);
2846         ret = proc_dostring(table, write, buffer, length, ppos);
2847         if (ret)
2848                 goto out;
2849         if (write) {
2850                 int oldval = user_zonelist_order;
2851                 if (__parse_numa_zonelist_order((char*)table->data)) {
2852                         /*
2853                          * bogus value.  restore saved string
2854                          */
2855                         strncpy((char*)table->data, saved_string,
2856                                 NUMA_ZONELIST_ORDER_LEN);
2857                         user_zonelist_order = oldval;
2858                 } else if (oldval != user_zonelist_order) {
2859                         mutex_lock(&zonelists_mutex);
2860                         build_all_zonelists(NULL);
2861                         mutex_unlock(&zonelists_mutex);
2862                 }
2863         }
2864 out:
2865         mutex_unlock(&zl_order_mutex);
2866         return ret;
2867 }
2868 
2869 
2870 #define MAX_NODE_LOAD (nr_online_nodes)
2871 static int node_load[MAX_NUMNODES];
2872 
2873 /**
2874  * find_next_best_node - find the next node that should appear in a given node's fallback list
2875  * @node: node whose fallback list we're appending
2876  * @used_node_mask: nodemask_t of already used nodes
2877  *
2878  * We use a number of factors to determine which is the next node that should
2879  * appear on a given node's fallback list.  The node should not have appeared
2880  * already in @node's fallback list, and it should be the next closest node
2881  * according to the distance array (which contains arbitrary distance values
2882  * from each node to each node in the system), and should also prefer nodes
2883  * with no CPUs, since presumably they'll have very little allocation pressure
2884  * on them otherwise.
2885  * It returns -1 if no node is found.
2886  */
2887 static int find_next_best_node(int node, nodemask_t *used_node_mask)
2888 {
2889         int n, val;
2890         int min_val = INT_MAX;
2891         int best_node = -1;
2892         const struct cpumask *tmp = cpumask_of_node(0);
2893 
2894         /* Use the local node if we haven't already */
2895         if (!node_isset(node, *used_node_mask)) {
2896                 node_set(node, *used_node_mask);
2897                 return node;
2898         }
2899 
2900         for_each_node_state(n, N_HIGH_MEMORY) {
2901 
2902                 /* Don't want a node to appear more than once */
2903                 if (node_isset(n, *used_node_mask))
2904                         continue;
2905 
2906                 /* Use the distance array to find the distance */
2907                 val = node_distance(node, n);
2908 
2909                 /* Penalize nodes under us ("prefer the next node") */
2910                 val += (n < node);
2911 
2912                 /* Give preference to headless and unused nodes */
2913                 tmp = cpumask_of_node(n);
2914                 if (!cpumask_empty(tmp))
2915                         val += PENALTY_FOR_NODE_WITH_CPUS;
2916 
2917                 /* Slight preference for less loaded node */
2918                 val *= (MAX_NODE_LOAD*MAX_NUMNODES);
2919                 val += node_load[n];
2920 
2921                 if (val < min_val) {
2922                         min_val = val;
2923                         best_node = n;
2924                 }
2925         }
2926 
2927         if (best_node >= 0)
2928                 node_set(best_node, *used_node_mask);
2929 
2930         return best_node;
2931 }
2932 
2933 
2934 /*
2935  * Build zonelists ordered by node and zones within node.
2936  * This results in maximum locality--normal zone overflows into local
2937  * DMA zone, if any--but risks exhausting DMA zone.
2938  */
2939 static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
2940 {
2941         int j;
2942         struct zonelist *zonelist;
2943 
2944         zonelist = &pgdat->node_zonelists[0];
2945         for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
2946                 ;
2947         j = build_zonelists_node(NODE_DATA(node), zonelist, j,
2948                                                         MAX_NR_ZONES - 1);
2949         zonelist->_zonerefs[j].zone = NULL;
2950         zonelist->_zonerefs[j].zone_idx = 0;
2951 }
2952 
2953 /*
2954  * Build gfp_thisnode zonelists
2955  */
2956 static void build_thisnode_zonelists(pg_data_t *pgdat)
2957 {
2958         int j;
2959         struct zonelist *zonelist;
2960 
2961         zonelist = &pgdat->node_zonelists[1];
2962         j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
2963         zonelist->_zonerefs[j].zone = NULL;
2964         zonelist->_zonerefs[j].zone_idx = 0;
2965 }
2966 
2967 /*
2968  * Build zonelists ordered by zone and nodes within zones.
2969  * This results in conserving DMA zone[s] until all Normal memory is
2970  * exhausted, but results in overflowing to remote node while memory
2971  * may still exist in local DMA zone.
2972  */
2973 static int node_order[MAX_NUMNODES];
2974 
2975 static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
2976 {
2977         int pos, j, node;
2978         int zone_type;          /* needs to be signed */
2979         struct zone *z;
2980         struct zonelist *zonelist;
2981 
2982         zonelist = &pgdat->node_zonelists[0];
2983         pos = 0;
2984         for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
2985                 for (j = 0; j < nr_nodes; j++) {
2986                         node = node_order[j];
2987                         z = &NODE_DATA(node)->node_zones[zone_type];
2988                         if (populated_zone(z)) {
2989                                 zoneref_set_zone(z,
2990                                         &zonelist->_zonerefs[pos++]);
2991                                 check_highest_zone(zone_type);
2992                         }
2993                 }
2994         }
2995         zonelist->_zonerefs[pos].zone = NULL;
2996         zonelist->_zonerefs[pos].zone_idx = 0;
2997 }
2998 
2999 static int default_zonelist_order(void)
3000 {
3001         int nid, zone_type;
3002         unsigned long low_kmem_size,total_size;
3003         struct zone *z;
3004         int average_size;
3005         /*
3006          * ZONE_DMA and ZONE_DMA32 can be very small area in the system.
3007          * If they are really small and used heavily, the system can fall
3008          * into OOM very easily.
3009          * This function detect ZONE_DMA/DMA32 size and configures zone order.
3010          */
3011         /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
3012         low_kmem_size = 0;
3013         total_size = 0;
3014         for_each_online_node(nid) {
3015                 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3016                         z = &NODE_DATA(nid)->node_zones[zone_type];
3017                         if (populated_zone(z)) {
3018                                 if (zone_type < ZONE_NORMAL)
3019                                         low_kmem_size += z->present_pages;
3020                                 total_size += z->present_pages;
3021                         } else if (zone_type == ZONE_NORMAL) {
3022                                 /*
3023                                  * If any node has only lowmem, then node order
3024                                  * is preferred to allow kernel allocations
3025                                  * locally; otherwise, they can easily infringe
3026                                  * on other nodes when there is an abundance of
3027                                  * lowmem available to allocate from.
3028                                  */
3029                                 return ZONELIST_ORDER_NODE;
3030                         }
3031                 }
3032         }
3033         if (!low_kmem_size ||  /* there are no DMA area. */
3034             low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
3035                 return ZONELIST_ORDER_NODE;
3036         /*
3037          * look into each node's config.
3038          * If there is a node whose DMA/DMA32 memory is very big area on
3039          * local memory, NODE_ORDER may be suitable.
3040          */
3041         average_size = total_size /
3042                                 (nodes_weight(node_states[N_HIGH_MEMORY]) + 1);
3043         for_each_online_node(nid) {
3044                 low_kmem_size = 0;
3045                 total_size = 0;
3046                 for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
3047                         z = &NODE_DATA(nid)->node_zones[zone_type];
3048                         if (populated_zone(z)) {
3049                                 if (zone_type < ZONE_NORMAL)
3050                                         low_kmem_size += z->present_pages;
3051                                 total_size += z->present_pages;
3052                         }
3053                 }
3054                 if (low_kmem_size &&
3055                     total_size > average_size && /* ignore small node */
3056                     low_kmem_size > total_size * 70/100)
3057                         return ZONELIST_ORDER_NODE;
3058         }
3059         return ZONELIST_ORDER_ZONE;
3060 }
3061 
3062 static void set_zonelist_order(void)
3063 {
3064         if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
3065                 current_zonelist_order = default_zonelist_order();
3066         else
3067                 current_zonelist_order = user_zonelist_order;
3068 }
3069 
3070 static void build_zonelists(pg_data_t *pgdat)
3071 {
3072         int j, node, load;
3073         enum zone_type i;
3074         nodemask_t used_mask;
3075         int local_node, prev_node;
3076         struct zonelist *zonelist;
3077         int order = current_zonelist_order;
3078 
3079         /* initialize zonelists */
3080         for (i = 0; i < MAX_ZONELISTS; i++) {
3081                 zonelist = pgdat->node_zonelists + i;
3082                 zonelist->_zonerefs[0].zone = NULL;
3083                 zonelist->_zonerefs[0].zone_idx = 0;
3084         }
3085 
3086         /* NUMA-aware ordering of nodes */
3087         local_node = pgdat->node_id;
3088         load = nr_online_nodes;
3089         prev_node = local_node;
3090         nodes_clear(used_mask);
3091 
3092         memset(node_order, 0, sizeof(node_order));
3093         j = 0;
3094 
3095         while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
3096                 int distance = node_distance(local_node, node);
3097 
3098                 /*
3099                  * If another node is sufficiently far away then it is better
3100                  * to reclaim pages in a zone before going off node.
3101                  */
3102                 if (distance > RECLAIM_DISTANCE)
3103                         zone_reclaim_mode = 1;
3104 
3105                 /*
3106                  * We don't want to pressure a particular node.
3107                  * So adding penalty to the first node in same
3108                  * distance group to make it round-robin.
3109                  */
3110                 if (distance != node_distance(local_node, prev_node))
3111                         node_load[node] = load;
3112 
3113                 prev_node = node;
3114                 load--;
3115                 if (order == ZONELIST_ORDER_NODE)
3116                         build_zonelists_in_node_order(pgdat, node);
3117                 else
3118                         node_order[j++] = node; /* remember order */
3119         }
3120 
3121         if (order == ZONELIST_ORDER_ZONE) {
3122                 /* calculate node order -- i.e., DMA last! */
3123                 build_zonelists_in_zone_order(pgdat, j);
3124         }
3125 
3126         build_thisnode_zonelists(pgdat);
3127 }
3128 
3129 /* Construct the zonelist performance cache - see further mmzone.h */
3130 static void build_zonelist_cache(pg_data_t *pgdat)
3131 {
3132         struct zonelist *zonelist;
3133         struct zonelist_cache *zlc;
3134         struct zoneref *z;
3135 
3136         zonelist = &pgdat->node_zonelists[0];
3137         zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
3138         bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
3139         for (z = zonelist->_zonerefs; z->zone; z++)
3140                 zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z);
3141 }
3142 
3143 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
3144 /*
3145  * Return node id of node used for "local" allocations.
3146  * I.e., first node id of first zone in arg node's generic zonelist.
3147  * Used for initializing percpu 'numa_mem', which is used primarily
3148  * for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
3149  */
3150 int local_memory_node(int node)
3151 {
3152         struct zone *zone;
3153 
3154         (void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
3155                                    gfp_zone(GFP_KERNEL),
3156                                    NULL,
3157                                    &zone);
3158         return zone->node;
3159 }
3160 #endif
3161 
3162 #else   /* CONFIG_NUMA */
3163 
3164 static void set_zonelist_order(void)
3165 {
3166         current_zonelist_order = ZONELIST_ORDER_ZONE;
3167 }
3168 
3169 static void build_zonelists(pg_data_t *pgdat)
3170 {
3171         int node, local_node;
3172         enum zone_type j;
3173         struct zonelist *zonelist;
3174 
3175         local_node = pgdat->node_id;
3176 
3177         zonelist = &pgdat->node_zonelists[0];
3178         j = build_zonelists_node(pgdat, zonelist, 0, MAX_NR_ZONES - 1);
3179 
3180         /*
3181          * Now we build the zonelist so that it contains the zones
3182          * of all the other nodes.
3183          * We don't want to pressure a particular node, so when
3184          * building the zones for node N, we make sure that the
3185          * zones coming right after the local ones are those from
3186          * node N+1 (modulo N)
3187          */
3188         for (node = local_node + 1; node < MAX_NUMNODES; node++) {
3189                 if (!node_online(node))
3190                         continue;
3191                 j = build_zonelists_node(NODE_DATA(node), zonelist, j,
3192                                                         MAX_NR_ZONES - 1);
3193         }
3194         for (node = 0; node < local_node; node++) {
3195                 if (!node_online(node))
3196                         continue;
3197                 j = build_zonelists_node(NODE_DATA(node), zonelist, j,
3198                                                         MAX_NR_ZONES - 1);
3199         }
3200 
3201         zonelist->_zonerefs[j].zone = NULL;
3202         zonelist->_zonerefs[j].zone_idx = 0;
3203 }
3204 
3205 /* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
3206 static void build_zonelist_cache(pg_data_t *pgdat)
3207 {
3208         pgdat->node_zonelists[0].zlcache_ptr = NULL;
3209 }
3210 
3211 #endif  /* CONFIG_NUMA */
3212 
3213 /*
3214  * Boot pageset table. One per cpu which is going to be used for all
3215  * zones and all nodes. The parameters will be set in such a way
3216  * that an item put on a list will immediately be handed over to
3217  * the buddy list. This is safe since pageset manipulation is done
3218  * with interrupts disabled.
3219  *
3220  * The boot_pagesets must be kept even after bootup is complete for
3221  * unused processors and/or zones. They do play a role for bootstrapping
3222  * hotplugged processors.
3223  *
3224  * zoneinfo_show() and maybe other functions do
3225  * not check if the processor is online before following the pageset pointer.
3226  * Other parts of the kernel may not check if the zone is available.
3227  */
3228 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
3229 static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
3230 static void setup_zone_pageset(struct zone *zone);
3231 
3232 /*
3233  * Global mutex to protect against size modification of zonelists
3234  * as well as to serialize pageset setup for the new populated zone.
3235  */
3236 DEFINE_MUTEX(zonelists_mutex);
3237 
3238 /* return values int ....just for stop_machine() */
3239 static __init_refok int __build_all_zonelists(void *data)
3240 {
3241         int nid;
3242         int cpu;
3243 
3244 #ifdef CONFIG_NUMA
3245         memset(node_load, 0, sizeof(node_load));
3246 #endif
3247         for_each_online_node(nid) {
3248                 pg_data_t *pgdat = NODE_DATA(nid);
3249 
3250                 build_zonelists(pgdat);
3251                 build_zonelist_cache(pgdat);
3252         }
3253 
3254         /*
3255          * Initialize the boot_pagesets that are going to be used
3256          * for bootstrapping processors. The real pagesets for
3257          * each zone will be allocated later when the per cpu
3258          * allocator is available.
3259          *
3260          * boot_pagesets are used also for bootstrapping offline
3261          * cpus if the system is already booted because the pagesets
3262          * are needed to initialize allocators on a specific cpu too.
3263          * F.e. the percpu allocator needs the page allocator which
3264          * needs the percpu allocator in order to allocate its pagesets
3265          * (a chicken-egg dilemma).
3266          */
3267         for_each_possible_cpu(cpu) {
3268                 setup_pageset(&per_cpu(boot_pageset, cpu), 0);
3269 
3270 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
3271                 /*
3272                  * We now know the "local memory node" for each node--
3273                  * i.e., the node of the first zone in the generic zonelist.
3274                  * Set up numa_mem percpu variable for on-line cpus.  During
3275                  * boot, only the boot cpu should be on-line;  we'll init the
3276                  * secondary cpus' numa_mem as they come on-line.  During
3277                  * node/memory hotplug, we'll fixup all on-line cpus.
3278                  */
3279                 if (cpu_online(cpu))
3280                         set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
3281 #endif
3282         }
3283 
3284         return 0;
3285 }
3286 
3287 /*
3288  * Called with zonelists_mutex held always
3289  * unless system_state == SYSTEM_BOOTING.
3290  */
3291 void __ref build_all_zonelists(void *data)
3292 {
3293         set_zonelist_order();
3294 
3295         if (system_state == SYSTEM_BOOTING) {
3296                 __build_all_zonelists(NULL);
3297                 mminit_verify_zonelist();
3298                 cpuset_init_current_mems_allowed();
3299         } else {
3300                 /* we have to stop all cpus to guarantee there is no user
3301                    of zonelist */
3302 #ifdef CONFIG_MEMORY_HOTPLUG
3303                 if (data)
3304                         setup_zone_pageset((struct zone *)data);
3305 #endif
3306                 stop_machine(__build_all_zonelists, NULL, NULL);
3307                 /* cpuset refresh routine should be here */
3308         }
3309         vm_total_pages = nr_free_pagecache_pages();
3310         /*
3311          * Disable grouping by mobility if the number of pages in the
3312          * system is too low to allow the mechanism to work. It would be
3313          * more accurate, but expensive to check per-zone. This check is
3314          * made on memory-hotadd so a system can start with mobility
3315          * disabled and enable it later
3316          */
3317         if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
3318                 page_group_by_mobility_disabled = 1;
3319         else
3320                 page_group_by_mobility_disabled = 0;
3321 
3322         printk("Built %i zonelists in %s order, mobility grouping %s.  "
3323                 "Total pages: %ld\n",
3324                         nr_online_nodes,
3325                         zonelist_order_name[current_zonelist_order],
3326                         page_group_by_mobility_disabled ? "off" : "on",
3327                         vm_total_pages);
3328 #ifdef CONFIG_NUMA
3329         printk("Policy zone: %s\n", zone_names[policy_zone]);
3330 #endif
3331 }
3332 
3333 /*
3334  * Helper functions to size the waitqueue hash table.
3335  * Essentially these want to choose hash table sizes sufficiently
3336  * large so that collisions trying to wait on pages are rare.
3337  * But in fact, the number of active page waitqueues on typical
3338  * systems is ridiculously low, less than 200. So this is even
3339  * conservative, even though it seems large.
3340  *
3341  * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
3342  * waitqueues, i.e. the size of the waitq table given the number of pages.
3343  */
3344 #define PAGES_PER_WAITQUEUE     256
3345 
3346 #ifndef CONFIG_MEMORY_HOTPLUG
3347 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3348 {
3349         unsigned long size = 1;
3350 
3351         pages /= PAGES_PER_WAITQUEUE;
3352 
3353         while (size < pages)
3354                 size <<= 1;
3355 
3356         /*
3357          * Once we have dozens or even hundreds of threads sleeping
3358          * on IO we've got bigger problems than wait queue collision.
3359          * Limit the size of the wait table to a reasonable size.
3360          */
3361         size = min(size, 4096UL);
3362 
3363         return max(size, 4UL);
3364 }
3365 #else
3366 /*
3367  * A zone's size might be changed by hot-add, so it is not possible to determine
3368  * a suitable size for its wait_table.  So we use the maximum size now.
3369  *
3370  * The max wait table size = 4096 x sizeof(wait_queue_head_t).   ie:
3371  *
3372  *    i386 (preemption config)    : 4096 x 16 = 64Kbyte.
3373  *    ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
3374  *    ia64, x86-64 (preemption)   : 4096 x 24 = 96Kbyte.
3375  *
3376  * The maximum entries are prepared when a zone's memory is (512K + 256) pages
3377  * or more by the traditional way. (See above).  It equals:
3378  *
3379  *    i386, x86-64, powerpc(4K page size) : =  ( 2G + 1M)byte.
3380  *    ia64(16K page size)                 : =  ( 8G + 4M)byte.
3381  *    powerpc (64K page size)             : =  (32G +16M)byte.
3382  */
3383 static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
3384 {
3385         return 4096UL;
3386 }
3387 #endif
3388 
3389 /*
3390  * This is an integer logarithm so that shifts can be used later
3391  * to extract the more random high bits from the multiplicative
3392  * hash function before the remainder is taken.
3393  */
3394 static inline unsigned long wait_table_bits(unsigned long size)
3395 {
3396         return ffz(~size);
3397 }
3398 
3399 #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
3400 
3401 /*
3402  * Check if a pageblock contains reserved pages
3403  */
3404 static int pageblock_is_reserved(unsigned long start_pfn, unsigned long end_pfn)
3405 {
3406         unsigned long pfn;
3407 
3408         for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3409                 if (!pfn_valid_within(pfn) || PageReserved(pfn_to_page(pfn)))
3410                         return 1;
3411         }
3412         return 0;
3413 }
3414 
3415 /*
3416  * Mark a number of pageblocks as MIGRATE_RESERVE. The number
3417  * of blocks reserved is based on min_wmark_pages(zone). The memory within
3418  * the reserve will tend to store contiguous free pages. Setting min_free_kbytes
3419  * higher will lead to a bigger reserve which will get freed as contiguous
3420  * blocks as reclaim kicks in
3421  */
3422 static void setup_zone_migrate_reserve(struct zone *zone)
3423 {
3424         unsigned long start_pfn, pfn, end_pfn, block_end_pfn;
3425         struct page *page;
3426         unsigned long block_migratetype;
3427         int reserve;
3428 
3429         /*
3430          * Get the start pfn, end pfn and the number of blocks to reserve
3431          * We have to be careful to be aligned to pageblock_nr_pages to
3432          * make sure that we always check pfn_valid for the first page in
3433          * the block.
3434          */
3435         start_pfn = zone->zone_start_pfn;
3436         end_pfn = start_pfn + zone->spanned_pages;
3437         start_pfn = roundup(start_pfn, pageblock_nr_pages);
3438         reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
3439                                                         pageblock_order;
3440 
3441         /*
3442          * Reserve blocks are generally in place to help high-order atomic
3443          * allocations that are short-lived. A min_free_kbytes value that
3444          * would result in more than 2 reserve blocks for atomic allocations
3445          * is assumed to be in place to help anti-fragmentation for the
3446          * future allocation of hugepages at runtime.
3447          */
3448         reserve = min(2, reserve);
3449 
3450         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
3451                 if (!pfn_valid(pfn))
3452                         continue;
3453                 page = pfn_to_page(pfn);
3454 
3455                 /* Watch out for overlapping nodes */
3456                 if (page_to_nid(page) != zone_to_nid(zone))
3457                         continue;
3458 
3459                 block_migratetype = get_pageblock_migratetype(page);
3460 
3461                 /* Only test what is necessary when the reserves are not met */
3462                 if (reserve > 0) {
3463                         /*
3464                          * Blocks with reserved pages will never free, skip
3465                          * them.
3466                          */
3467                         block_end_pfn = min(pfn + pageblock_nr_pages, end_pfn);
3468                         if (pageblock_is_reserved(pfn, block_end_pfn))
3469                                 continue;
3470 
3471                         /* If this block is reserved, account for it */
3472                         if (block_migratetype == MIGRATE_RESERVE) {
3473                                 reserve--;
3474                                 continue;
3475                         }
3476 
3477                         /* Suitable for reserving if this block is movable */
3478                         if (block_migratetype == MIGRATE_MOVABLE) {
3479                                 set_pageblock_migratetype(page,
3480                                                         MIGRATE_RESERVE);
3481                                 move_freepages_block(zone, page,
3482                                                         MIGRATE_RESERVE);
3483                                 reserve--;
3484                                 continue;
3485                         }
3486                 }
3487 
3488                 /*
3489                  * If the reserve is met and this is a previous reserved block,
3490                  * take it back
3491                  */
3492                 if (block_migratetype == MIGRATE_RESERVE) {
3493                         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3494                         move_freepages_block(zone, page, MIGRATE_MOVABLE);
3495                 }
3496         }
3497 }
3498 
3499 /*
3500  * Initially all pages are reserved - free ones are freed
3501  * up by free_all_bootmem() once the early boot process is
3502  * done. Non-atomic initialization, single-pass.
3503  */
3504 void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
3505                 unsigned long start_pfn, enum memmap_context context)
3506 {
3507         struct page *page;
3508         unsigned long end_pfn = start_pfn + size;
3509         unsigned long pfn;
3510         struct zone *z;
3511 
3512         if (highest_memmap_pfn < end_pfn - 1)
3513                 highest_memmap_pfn = end_pfn - 1;
3514 
3515         z = &NODE_DATA(nid)->node_zones[zone];
3516         for (pfn = start_pfn; pfn < end_pfn; pfn++) {
3517                 /*
3518                  * There can be holes in boot-time mem_map[]s
3519                  * handed to this function.  They do not
3520                  * exist on hotplugged memory.
3521                  */
3522                 if (context == MEMMAP_EARLY) {
3523                         if (!early_pfn_valid(pfn))
3524                                 continue;
3525                         if (!early_pfn_in_nid(pfn, nid))
3526                                 continue;
3527                 }
3528                 page = pfn_to_page(pfn);
3529                 set_page_links(page, zone, nid, pfn);
3530                 mminit_verify_page_links(page, zone, nid, pfn);
3531                 init_page_count(page);
3532                 reset_page_mapcount(page);
3533                 SetPageReserved(page);
3534                 /*
3535                  * Mark the block movable so that blocks are reserved for
3536                  * movable at startup. This will force kernel allocations
3537                  * to reserve their blocks rather than leaking throughout
3538                  * the address space during boot when many long-lived
3539                  * kernel allocations are made. Later some blocks near
3540                  * the start are marked MIGRATE_RESERVE by
3541                  * setup_zone_migrate_reserve()
3542                  *
3543                  * bitmap is created for zone's valid pfn range. but memmap
3544                  * can be created for invalid pages (for alignment)
3545                  * check here not to call set_pageblock_migratetype() against
3546                  * pfn out of zone.
3547                  */
3548                 if ((z->zone_start_pfn <= pfn)
3549                     && (pfn < z->zone_start_pfn + z->spanned_pages)
3550                     && !(pfn & (pageblock_nr_pages - 1)))
3551                         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
3552 
3553                 INIT_LIST_HEAD(&page->lru);
3554 #ifdef WANT_PAGE_VIRTUAL
3555                 /* The shift won't overflow because ZONE_NORMAL is below 4G. */
3556                 if (!is_highmem_idx(zone))
3557                         set_page_address(page, __va(pfn << PAGE_SHIFT));
3558 #endif
3559         }
3560 }
3561 
3562 static void __meminit zone_init_free_lists(struct zone *zone)
3563 {
3564         int order, t;
3565         for_each_migratetype_order(order, t) {
3566                 INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
3567                 zone->free_area[order].nr_free = 0;
3568         }
3569 }
3570 
3571 #ifndef __HAVE_ARCH_MEMMAP_INIT
3572 #define memmap_init(size, nid, zone, start_pfn) \
3573         memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
3574 #endif
3575 
3576 static int zone_batchsize(struct zone *zone)
3577 {
3578 #ifdef CONFIG_MMU
3579         int batch;
3580 
3581         /*
3582          * The per-cpu-pages pools are set to around 1000th of the
3583          * size of the zone.  But no more than 1/2 of a meg.
3584          *
3585          * OK, so we don't know how big the cache is.  So guess.
3586          */
3587         batch = zone->present_pages / 1024;
3588         if (batch * PAGE_SIZE > 512 * 1024)
3589                 batch = (512 * 1024) / PAGE_SIZE;
3590         batch /= 4;             /* We effectively *= 4 below */
3591         if (batch < 1)
3592                 batch = 1;
3593 
3594         /*
3595          * Clamp the batch to a 2^n - 1 value. Having a power
3596          * of 2 value was found to be more likely to have
3597          * suboptimal cache aliasing properties in some cases.
3598          *
3599          * For example if 2 tasks are alternately allocating
3600          * batches of pages, one task can end up with a lot
3601          * of pages of one half of the possible page colors
3602          * and the other with pages of the other colors.
3603          */
3604         batch = rounddown_pow_of_two(batch + batch/2) - 1;
3605 
3606         return batch;
3607 
3608 #else
3609         /* The deferral and batching of frees should be suppressed under NOMMU
3610          * conditions.
3611          *
3612          * The problem is that NOMMU needs to be able to allocate large chunks
3613          * of contiguous memory as there's no hardware page translation to
3614          * assemble apparent contiguous memory from discontiguous pages.
3615          *
3616          * Queueing large contiguous runs of pages for batching, however,
3617          * causes the pages to actually be freed in smaller chunks.  As there
3618          * can be a significant delay between the individual batches being
3619          * recycled, this leads to the once large chunks of space being
3620          * fragmented and becoming unavailable for high-order allocations.
3621          */
3622         return 0;
3623 #endif
3624 }
3625 
3626 static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
3627 {
3628         struct per_cpu_pages *pcp;
3629         int migratetype;
3630 
3631         memset(p, 0, sizeof(*p));
3632 
3633         pcp = &p->pcp;
3634         pcp->count = 0;
3635         pcp->high = 6 * batch;
3636         pcp->batch = max(1UL, 1 * batch);
3637         for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
3638                 INIT_LIST_HEAD(&pcp->lists[migratetype]);
3639 }
3640 
3641 /*
3642  * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
3643  * to the value high for the pageset p.
3644  */
3645 
3646 static void setup_pagelist_highmark(struct per_cpu_pageset *p,
3647                                 unsigned long high)
3648 {
3649         struct per_cpu_pages *pcp;
3650 
3651         pcp = &p->pcp;
3652         pcp->high = high;
3653         pcp->batch = max(1UL, high/4);
3654         if ((high/4) > (PAGE_SHIFT * 8))
3655                 pcp->batch = PAGE_SHIFT * 8;
3656 }
3657 
3658 static void setup_zone_pageset(struct zone *zone)
3659 {
3660         int cpu;
3661 
3662         zone->pageset = alloc_percpu(struct per_cpu_pageset);
3663 
3664         for_each_possible_cpu(cpu) {
3665                 struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
3666 
3667                 setup_pageset(pcp, zone_batchsize(zone));
3668 
3669                 if (percpu_pagelist_fraction)
3670                         setup_pagelist_highmark(pcp,
3671                                 (zone->present_pages /
3672                                         percpu_pagelist_fraction));
3673         }
3674 }
3675 
3676 /*
3677  * Allocate per cpu pagesets and initialize them.
3678  * Before this call only boot pagesets were available.
3679  */
3680 void __init setup_per_cpu_pageset(void)
3681 {
3682         struct zone *zone;
3683 
3684         for_each_populated_zone(zone)
3685                 setup_zone_pageset(zone);
3686 }
3687 
3688 static noinline __init_refok
3689 int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
3690 {
3691         int i;
3692         struct pglist_data *pgdat = zone->zone_pgdat;
3693         size_t alloc_size;
3694 
3695         /*
3696          * The per-page waitqueue mechanism uses hashed waitqueues
3697          * per zone.
3698          */
3699         zone->wait_table_hash_nr_entries =
3700                  wait_table_hash_nr_entries(zone_size_pages);
3701         zone->wait_table_bits =
3702                 wait_table_bits(zone->wait_table_hash_nr_entries);
3703         alloc_size = zone->wait_table_hash_nr_entries
3704                                         * sizeof(wait_queue_head_t);
3705 
3706         if (!slab_is_available()) {
3707                 zone->wait_table = (wait_queue_head_t *)
3708                         alloc_bootmem_node_nopanic(pgdat, alloc_size);
3709         } else {
3710                 /*
3711                  * This case means that a zone whose size was 0 gets new memory
3712                  * via memory hot-add.
3713                  * But it may be the case that a new node was hot-added.  In
3714                  * this case vmalloc() will not be able to use this new node's
3715                  * memory - this wait_table must be initialized to use this new
3716                  * node itself as well.
3717                  * To use this new node's memory, further consideration will be
3718                  * necessary.
3719                  */
3720                 zone->wait_table = vmalloc(alloc_size);
3721         }
3722         if (!zone->wait_table)
3723                 return -ENOMEM;
3724 
3725         for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
3726                 init_waitqueue_head(zone->wait_table + i);
3727 
3728         return 0;
3729 }
3730 
3731 static int __zone_pcp_update(void *data)
3732 {
3733         struct zone *zone = data;
3734         int cpu;
3735         unsigned long batch = zone_batchsize(zone), flags;
3736 
3737         for_each_possible_cpu(cpu) {
3738                 struct per_cpu_pageset *pset;
3739                 struct per_cpu_pages *pcp;
3740 
3741                 pset = per_cpu_ptr(zone->pageset, cpu);
3742                 pcp = &pset->pcp;
3743 
3744                 local_irq_save(flags);
3745                 free_pcppages_bulk(zone, pcp->count, pcp);
3746                 setup_pageset(pset, batch);
3747                 local_irq_restore(flags);
3748         }
3749         return 0;
3750 }
3751 
3752 void zone_pcp_update(struct zone *zone)
3753 {
3754         stop_machine(__zone_pcp_update, zone, NULL);
3755 }
3756 
3757 static __meminit void zone_pcp_init(struct zone *zone)
3758 {
3759         /*
3760          * per cpu subsystem is not up at this point. The following code
3761          * relies on the ability of the linker to provide the
3762          * offset of a (static) per cpu variable into the per cpu area.
3763          */
3764         zone->pageset = &boot_pageset;
3765 
3766         if (zone->present_pages)
3767                 printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%u\n",
3768                         zone->name, zone->present_pages,
3769                                          zone_batchsize(zone));
3770 }
3771 
3772 __meminit int init_currently_empty_zone(struct zone *zone,
3773                                         unsigned long zone_start_pfn,
3774                                         unsigned long size,
3775                                         enum memmap_context context)
3776 {
3777         struct pglist_data *pgdat = zone->zone_pgdat;
3778         int ret;
3779         ret = zone_wait_table_init(zone, size);
3780         if (ret)
3781                 return ret;
3782         pgdat->nr_zones = zone_idx(zone) + 1;
3783 
3784         zone->zone_start_pfn = zone_start_pfn;
3785 
3786         mminit_dprintk(MMINIT_TRACE, "memmap_init",
3787                         "Initialising map node %d zone %lu pfns %lu -> %lu\n",
3788                         pgdat->node_id,
3789                         (unsigned long)zone_idx(zone),
3790                         zone_start_pfn, (zone_start_pfn + size));
3791 
3792         zone_init_free_lists(zone);
3793 
3794         return 0;
3795 }
3796 
3797 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
3798 /*
3799  * Basic iterator support. Return the first range of PFNs for a node
3800  * Note: nid == MAX_NUMNODES returns first region regardless of node
3801  */
3802 static int __meminit first_active_region_index_in_nid(int nid)
3803 {
3804         int i;
3805 
3806         for (i = 0; i < nr_nodemap_entries; i++)
3807                 if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
3808                         return i;
3809 
3810         return -1;
3811 }
3812 
3813 /*
3814  * Basic iterator support. Return the next active range of PFNs for a node
3815  * Note: nid == MAX_NUMNODES returns next region regardless of node
3816  */
3817 static int __meminit next_active_region_index_in_nid(int index, int nid)
3818 {
3819         for (index = index + 1; index < nr_nodemap_entries; index++)
3820                 if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
3821                         return index;
3822 
3823         return -1;
3824 }
3825 
3826 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
3827 /*
3828  * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
3829  * Architectures may implement their own version but if add_active_range()
3830  * was used and there are no special requirements, this is a convenient
3831  * alternative
3832  */
3833 int __meminit __early_pfn_to_nid(unsigned long pfn)
3834 {
3835         int i;
3836 
3837         for (i = 0; i < nr_nodemap_entries; i++) {
3838                 unsigned long start_pfn = early_node_map[i].start_pfn;
3839                 unsigned long end_pfn = early_node_map[i].end_pfn;
3840 
3841                 if (start_pfn <= pfn && pfn < end_pfn)
3842                         return early_node_map[i].nid;
3843         }
3844         /* This is a memory hole */
3845         return -1;
3846 }
3847 #endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
3848 
3849 int __meminit early_pfn_to_nid(unsigned long pfn)
3850 {
3851         int nid;
3852 
3853         nid = __early_pfn_to_nid(pfn);
3854         if (nid >= 0)
3855                 return nid;
3856         /* just returns 0 */
3857         return 0;
3858 }
3859 
3860 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
3861 bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
3862 {
3863         int nid;
3864 
3865         nid = __early_pfn_to_nid(pfn);
3866         if (nid >= 0 && nid != node)
3867                 return false;
3868         return true;
3869 }
3870 #endif
3871 
3872 /* Basic iterator support to walk early_node_map[] */
3873 #define for_each_active_range_index_in_nid(i, nid) \
3874         for (i = first_active_region_index_in_nid(nid); i != -1; \
3875                                 i = next_active_region_index_in_nid(i, nid))
3876 
3877 /**
3878  * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
3879  * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
3880  * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
3881  *
3882  * If an architecture guarantees that all ranges registered with
3883  * add_active_ranges() contain no holes and may be freed, this
3884  * this function may be used instead of calling free_bootmem() manually.
3885  */
3886 void __init free_bootmem_with_active_regions(int nid,
3887                                                 unsigned long max_low_pfn)
3888 {
3889         int i;
3890 
3891         for_each_active_range_index_in_nid(i, nid) {
3892                 unsigned long size_pages = 0;
3893                 unsigned long end_pfn = early_node_map[i].end_pfn;
3894 
3895                 if (early_node_map[i].start_pfn >= max_low_pfn)
3896                         continue;
3897 
3898                 if (end_pfn > max_low_pfn)
3899                         end_pfn = max_low_pfn;
3900 
3901                 size_pages = end_pfn - early_node_map[i].start_pfn;
3902                 free_bootmem_node(NODE_DATA(early_node_map[i].nid),
3903                                 PFN_PHYS(early_node_map[i].start_pfn),
3904                                 size_pages << PAGE_SHIFT);
3905         }
3906 }
3907 
3908 #ifdef CONFIG_HAVE_MEMBLOCK
3909 /*
3910  * Basic iterator support. Return the last range of PFNs for a node
3911  * Note: nid == MAX_NUMNODES returns last region regardless of node
3912  */
3913 static int __meminit last_active_region_index_in_nid(int nid)
3914 {
3915         int i;
3916 
3917         for (i = nr_nodemap_entries - 1; i >= 0; i--)
3918                 if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
3919                         return i;
3920 
3921         return -1;
3922 }
3923 
3924 /*
3925  * Basic iterator support. Return the previous active range of PFNs for a node
3926  * Note: nid == MAX_NUMNODES returns next region regardless of node
3927  */
3928 static int __meminit previous_active_region_index_in_nid(int index, int nid)
3929 {
3930         for (index = index - 1; index >= 0; index--)
3931                 if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
3932                         return index;
3933 
3934         return -1;
3935 }
3936 
3937 #define for_each_active_range_index_in_nid_reverse(i, nid) \
3938         for (i = last_active_region_index_in_nid(nid); i != -1; \
3939                                 i = previous_active_region_index_in_nid(i, nid))
3940 
3941 u64 __init find_memory_core_early(int nid, u64 size, u64 align,
3942                                         u64 goal, u64 limit)
3943 {
3944         int i;
3945 
3946         /* Need to go over early_node_map to find out good range for node */
3947         for_each_active_range_index_in_nid_reverse(i, nid) {
3948                 u64 addr;
3949                 u64 ei_start, ei_last;
3950                 u64 final_start, final_end;
3951 
3952                 ei_last = early_node_map[i].end_pfn;
3953                 ei_last <<= PAGE_SHIFT;
3954                 ei_start = early_node_map[i].start_pfn;
3955                 ei_start <<= PAGE_SHIFT;
3956 
3957                 final_start = max(ei_start, goal);
3958                 final_end = min(ei_last, limit);
3959 
3960                 if (final_start >= final_end)
3961                         continue;
3962 
3963                 addr = memblock_find_in_range(final_start, final_end, size, align);
3964 
3965                 if (addr == MEMBLOCK_ERROR)
3966                         continue;
3967 
3968                 return addr;
3969         }
3970 
3971         return MEMBLOCK_ERROR;
3972 }
3973 #endif
3974 
3975 int __init add_from_early_node_map(struct range *range, int az,
3976                                    int nr_range, int nid)
3977 {
3978         int i;
3979         u64 start, end;
3980 
3981         /* need to go over early_node_map to find out good range for node */
3982         for_each_active_range_index_in_nid(i, nid) {
3983                 start = early_node_map[i].start_pfn;
3984                 end = early_node_map[i].end_pfn;
3985                 nr_range = add_range(range, az, nr_range, start, end);
3986         }
3987         return nr_range;
3988 }
3989 
3990 void __init work_with_active_regions(int nid, work_fn_t work_fn, void *data)
3991 {
3992         int i;
3993         int ret;
3994 
3995         for_each_active_range_index_in_nid(i, nid) {
3996                 ret = work_fn(early_node_map[i].start_pfn,
3997                               early_node_map[i].end_pfn, data);
3998                 if (ret)
3999                         break;
4000         }
4001 }
4002 /**
4003  * sparse_memory_present_with_active_regions - Call memory_present for each active range
4004  * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
4005  *
4006  * If an architecture guarantees that all ranges registered with
4007  * add_active_ranges() contain no holes and may be freed, this
4008  * function may be used instead of calling memory_present() manually.
4009  */
4010 void __init sparse_memory_present_with_active_regions(int nid)
4011 {
4012         int i;
4013 
4014         for_each_active_range_index_in_nid(i, nid)
4015                 memory_present(early_node_map[i].nid,
4016                                 early_node_map[i].start_pfn,
4017                                 early_node_map[i].end_pfn);
4018 }
4019 
4020 /**
4021  * get_pfn_range_for_nid - Return the start and end page frames for a node
4022  * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
4023  * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
4024  * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
4025  *
4026  * It returns the start and end page frame of a node based on information
4027  * provided by an arch calling add_active_range(). If called for a node
4028  * with no available memory, a warning is printed and the start and end
4029  * PFNs will be 0.
4030  */
4031 void __meminit get_pfn_range_for_nid(unsigned int nid,
4032                         unsigned long *start_pfn, unsigned long *end_pfn)
4033 {
4034         int i;
4035         *start_pfn = -1UL;
4036         *end_pfn = 0;
4037 
4038         for_each_active_range_index_in_nid(i, nid) {
4039                 *start_pfn = min(*start_pfn, early_node_map[i].start_pfn);
4040                 *end_pfn = max(*end_pfn, early_node_map[i].end_pfn);
4041         }
4042 
4043         if (*start_pfn == -1UL)
4044                 *start_pfn = 0;
4045 }
4046 
4047 /*
4048  * This finds a zone that can be used for ZONE_MOVABLE pages. The
4049  * assumption is made that zones within a node are ordered in monotonic
4050  * increasing memory addresses so that the "highest" populated zone is used
4051  */
4052 static void __init find_usable_zone_for_movable(void)
4053 {
4054         int zone_index;
4055         for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
4056                 if (zone_index == ZONE_MOVABLE)
4057                         continue;
4058 
4059                 if (arch_zone_highest_possible_pfn[zone_index] >
4060                                 arch_zone_lowest_possible_pfn[zone_index])
4061                         break;
4062         }
4063 
4064         VM_BUG_ON(zone_index == -1);
4065         movable_zone = zone_index;
4066 }
4067 
4068 /*
4069  * The zone ranges provided by the architecture do not include ZONE_MOVABLE
4070  * because it is sized independent of architecture. Unlike the other zones,
4071  * the starting point for ZONE_MOVABLE is not fixed. It may be different
4072  * in each node depending on the size of each node and how evenly kernelcore
4073  * is distributed. This helper function adjusts the zone ranges
4074  * provided by the architecture for a given node by using the end of the
4075  * highest usable zone for ZONE_MOVABLE. This preserves the assumption that
4076  * zones within a node are in order of monotonic increases memory addresses
4077  */
4078 static void __meminit adjust_zone_range_for_zone_movable(int nid,
4079                                         unsigned long zone_type,
4080                                         unsigned long node_start_pfn,
4081                                         unsigned long node_end_pfn,
4082                                         unsigned long *zone_start_pfn,
4083                                         unsigned long *zone_end_pfn)
4084 {
4085         /* Only adjust if ZONE_MOVABLE is on this node */
4086         if (zone_movable_pfn[nid]) {
4087                 /* Size ZONE_MOVABLE */
4088                 if (zone_type == ZONE_MOVABLE) {
4089                         *zone_start_pfn = zone_movable_pfn[nid];
4090                         *zone_end_pfn = min(node_end_pfn,
4091                                 arch_zone_highest_possible_pfn[movable_zone]);
4092 
4093                 /* Adjust for ZONE_MOVABLE starting within this range */
4094                 } else if (*zone_start_pfn < zone_movable_pfn[nid] &&
4095                                 *zone_end_pfn > zone_movable_pfn[nid]) {
4096                         *zone_end_pfn = zone_movable_pfn[nid];
4097 
4098                 /* Check if this whole range is within ZONE_MOVABLE */
4099                 } else if (*zone_start_pfn >= zone_movable_pfn[nid])
4100                         *zone_start_pfn = *zone_end_pfn;
4101         }
4102 }
4103 
4104 /*
4105  * Return the number of pages a zone spans in a node, including holes
4106  * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
4107  */
4108 static unsigned long __meminit zone_spanned_pages_in_node(int nid,
4109                                         unsigned long zone_type,
4110                                         unsigned long *ignored)
4111 {
4112         unsigned long node_start_pfn, node_end_pfn;
4113         unsigned long zone_start_pfn, zone_end_pfn;
4114 
4115         /* Get the start and end of the node and zone */
4116         get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
4117         zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
4118         zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
4119         adjust_zone_range_for_zone_movable(nid, zone_type,
4120                                 node_start_pfn, node_end_pfn,
4121                                 &zone_start_pfn, &zone_end_pfn);
4122 
4123         /* Check that this node has pages within the zone's required range */
4124         if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
4125                 return 0;
4126 
4127         /* Move the zone boundaries inside the node if necessary */
4128         zone_end_pfn = min(zone_end_pfn, node_end_pfn);
4129         zone_start_pfn = max(zone_start_pfn, node_start_pfn);
4130 
4131         /* Return the spanned pages */
4132         return zone_end_pfn - zone_start_pfn;
4133 }
4134 
4135 /*
4136  * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
4137  * then all holes in the requested range will be accounted for.
4138  */
4139 unsigned long __meminit __absent_pages_in_range(int nid,
4140                                 unsigned long range_start_pfn,
4141                                 unsigned long range_end_pfn)
4142 {
4143         int i = 0;
4144         unsigned long prev_end_pfn = 0, hole_pages = 0;
4145         unsigned long start_pfn;
4146 
4147         /* Find the end_pfn of the first active range of pfns in the node */
4148         i = first_active_region_index_in_nid(nid);
4149         if (i == -1)
4150                 return 0;
4151 
4152         prev_end_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
4153 
4154         /* Account for ranges before physical memory on this node */
4155         if (early_node_map[i].start_pfn > range_start_pfn)
4156                 hole_pages = prev_end_pfn - range_start_pfn;
4157 
4158         /* Find all holes for the zone within the node */
4159         for (; i != -1; i = next_active_region_index_in_nid(i, nid)) {
4160 
4161                 /* No need to continue if prev_end_pfn is outside the zone */
4162                 if (prev_end_pfn >= range_end_pfn)
4163                         break;
4164 
4165                 /* Make sure the end of the zone is not within the hole */
4166                 start_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
4167                 prev_end_pfn = max(prev_end_pfn, range_start_pfn);
4168 
4169                 /* Update the hole size cound and move on */
4170                 if (start_pfn > range_start_pfn) {
4171                         BUG_ON(prev_end_pfn > start_pfn);
4172                         hole_pages += start_pfn - prev_end_pfn;
4173                 }
4174                 prev_end_pfn = early_node_map[i].end_pfn;
4175         }
4176 
4177         /* Account for ranges past physical memory on this node */
4178         if (range_end_pfn > prev_end_pfn)
4179                 hole_pages += range_end_pfn -
4180                                 max(range_start_pfn, prev_end_pfn);
4181 
4182         return hole_pages;
4183 }
4184 
4185 /**
4186  * absent_pages_in_range - Return number of page frames in holes within a range
4187  * @start_pfn: The start PFN to start searching for holes
4188  * @end_pfn: The end PFN to stop searching for holes
4189  *
4190  * It returns the number of pages frames in memory holes within a range.
4191  */
4192 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
4193                                                         unsigned long end_pfn)
4194 {
4195         return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
4196 }
4197 
4198 /* Return the number of page frames in holes in a zone on a node */
4199 static unsigned long __meminit zone_absent_pages_in_node(int nid,
4200                                         unsigned long zone_type,
4201                                         unsigned long *ignored)
4202 {
4203         unsigned long node_start_pfn, node_end_pfn;
4204         unsigned long zone_start_pfn, zone_end_pfn;
4205 
4206         get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
4207         zone_start_pfn = max(arch_zone_lowest_possible_pfn[zone_type],
4208                                                         node_start_pfn);
4209         zone_end_pfn = min(arch_zone_highest_possible_pfn[zone_type],
4210                                                         node_end_pfn);
4211 
4212         adjust_zone_range_for_zone_movable(nid, zone_type,
4213                         node_start_pfn, node_end_pfn,
4214                         &zone_start_pfn, &zone_end_pfn);
4215         return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
4216 }
4217 
4218 #else
4219 static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
4220                                         unsigned long zone_type,
4221                                         unsigned long *zones_size)
4222 {
4223         return zones_size[zone_type];
4224 }
4225 
4226 static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
4227                                                 unsigned long zone_type,
4228                                                 unsigned long *zholes_size)
4229 {
4230         if (!zholes_size)
4231                 return 0;
4232 
4233         return zholes_size[zone_type];
4234 }
4235 
4236 #endif
4237 
4238 static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
4239                 unsigned long *zones_size, unsigned long *zholes_size)
4240 {
4241         unsigned long realtotalpages, totalpages = 0;
4242         enum zone_type i;
4243 
4244         for (i = 0; i < MAX_NR_ZONES; i++)
4245                 totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
4246                                                                 zones_size);
4247         pgdat->node_spanned_pages = totalpages;
4248 
4249         realtotalpages = totalpages;
4250         for (i = 0; i < MAX_NR_ZONES; i++)
4251                 realtotalpages -=
4252                         zone_absent_pages_in_node(pgdat->node_id, i,
4253                                                                 zholes_size);
4254         pgdat->node_present_pages = realtotalpages;
4255         printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
4256                                                         realtotalpages);
4257 }
4258 
4259 #ifndef CONFIG_SPARSEMEM
4260 /*
4261  * Calculate the size of the zone->blockflags rounded to an unsigned long
4262  * Start by making sure zonesize is a multiple of pageblock_order by rounding
4263  * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
4264  * round what is now in bits to nearest long in bits, then return it in
4265  * bytes.
4266  */
4267 static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
4268 {
4269         unsigned long usemapsize;
4270 
4271         zonesize += zone_start_pfn & (pageblock_nr_pages-1);
4272         usemapsize = roundup(zonesize, pageblock_nr_pages);
4273         usemapsize = usemapsize >> pageblock_order;
4274         usemapsize *= NR_PAGEBLOCK_BITS;
4275         usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
4276 
4277         return usemapsize / 8;
4278 }
4279 
4280 static void __init setup_usemap(struct pglist_data *pgdat,
4281                                 struct zone *zone,
4282                                 unsigned long zone_start_pfn,
4283                                 unsigned long zonesize)
4284 {
4285         unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
4286         zone->pageblock_flags = NULL;
4287         if (usemapsize)
4288                 zone->pageblock_flags = alloc_bootmem_node_nopanic(pgdat,
4289                                                                    usemapsize);
4290 }
4291 #else
4292 static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
4293                                 unsigned long zone_start_pfn, unsigned long zonesize) {}
4294 #endif /* CONFIG_SPARSEMEM */
4295 
4296 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
4297 
4298 /* Return a sensible default order for the pageblock size. */
4299 static inline int pageblock_default_order(void)
4300 {
4301         if (HPAGE_SHIFT > PAGE_SHIFT)
4302                 return HUGETLB_PAGE_ORDER;
4303 
4304         return MAX_ORDER-1;
4305 }
4306 
4307 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
4308 static inline void __init set_pageblock_order(unsigned int order)
4309 {
4310         /* Check that pageblock_nr_pages has not already been setup */
4311         if (pageblock_order)
4312                 return;
4313 
4314         /*
4315          * Assume the largest contiguous order of interest is a huge page.
4316          * This value may be variable depending on boot parameters on IA64
4317          */
4318         pageblock_order = order;
4319 }
4320 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4321 
4322 /*
4323  * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
4324  * and pageblock_default_order() are unused as pageblock_order is set
4325  * at compile-time. See include/linux/pageblock-flags.h for the values of
4326  * pageblock_order based on the kernel config
4327  */
4328 static inline int pageblock_default_order(unsigned int order)
4329 {
4330         return MAX_ORDER-1;
4331 }
4332 #define set_pageblock_order(x)  do {} while (0)
4333 
4334 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
4335 
4336 /*
4337  * Set up the zone data structures:
4338  *   - mark all pages reserved
4339  *   - mark all memory queues empty
4340  *   - clear the memory bitmaps
4341  */
4342 static void __paginginit free_area_init_core(struct pglist_data *pgdat,
4343                 unsigned long *zones_size, unsigned long *zholes_size)
4344 {
4345         enum zone_type j;
4346         int nid = pgdat->node_id;
4347         unsigned long zone_start_pfn = pgdat->node_start_pfn;
4348         int ret;
4349 
4350         pgdat_resize_init(pgdat);
4351         pgdat->nr_zones = 0;
4352         init_waitqueue_head(&pgdat->kswapd_wait);
4353         pgdat->kswapd_max_order = 0;
4354         pgdat_page_cgroup_init(pgdat);
4355         
4356         for (j = 0; j < MAX_NR_ZONES; j++) {
4357                 struct zone *zone = pgdat->node_zones + j;
4358                 unsigned long size, realsize, memmap_pages;
4359                 enum lru_list l;
4360 
4361                 size = zone_spanned_pages_in_node(nid, j, zones_size);
4362                 realsize = size - zone_absent_pages_in_node(nid, j,
4363                                                                 zholes_size);
4364 
4365                 /*
4366                  * Adjust realsize so that it accounts for how much memory
4367                  * is used by this zone for memmap. This affects the watermark
4368                  * and per-cpu initialisations
4369                  */
4370                 memmap_pages =
4371                         PAGE_ALIGN(size * sizeof(struct page)) >> PAGE_SHIFT;
4372                 if (realsize >= memmap_pages) {
4373                         realsize -= memmap_pages;
4374                         if (memmap_pages)
4375                                 printk(KERN_DEBUG
4376                                        "  %s zone: %lu pages used for memmap\n",
4377                                        zone_names[j], memmap_pages);
4378                 } else
4379                         printk(KERN_WARNING
4380                                 "  %s zone: %lu pages exceeds realsize %lu\n",
4381                                 zone_names[j], memmap_pages, realsize);
4382 
4383                 /* Account for reserved pages */
4384                 if (j == 0 && realsize > dma_reserve) {
4385                         realsize -= dma_reserve;
4386                         printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
4387                                         zone_names[0], dma_reserve);
4388                 }
4389 
4390                 if (!is_highmem_idx(j))
4391                         nr_kernel_pages += realsize;
4392                 nr_all_pages += realsize;
4393 
4394                 zone->spanned_pages = size;
4395                 zone->present_pages = realsize;
4396 #ifdef CONFIG_NUMA
4397                 zone->node = nid;
4398                 zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
4399                                                 / 100;
4400                 zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
4401 #endif
4402                 zone->name = zone_names[j];
4403                 spin_lock_init(&zone->lock);
4404                 spin_lock_init(&zone->lru_lock);
4405                 zone_seqlock_init(zone);
4406                 zone->zone_pgdat = pgdat;
4407 
4408                 zone_pcp_init(zone);
4409                 for_each_lru(l)
4410                         INIT_LIST_HEAD(&zone->lru[l].list);
4411                 zone->reclaim_stat.recent_rotated[0] = 0;
4412                 zone->reclaim_stat.recent_rotated[1] = 0;
4413                 zone->reclaim_stat.recent_scanned[0] = 0;
4414                 zone->reclaim_stat.recent_scanned[1] = 0;
4415                 zap_zone_vm_stats(zone);
4416                 zone->flags = 0;
4417                 if (!size)
4418                         continue;
4419 
4420                 set_pageblock_order(pageblock_default_order());
4421                 setup_usemap(pgdat, zone, zone_start_pfn, size);
4422                 ret = init_currently_empty_zone(zone, zone_start_pfn,
4423                                                 size, MEMMAP_EARLY);
4424                 BUG_ON(ret);
4425                 memmap_init(size, nid, j, zone_start_pfn);
4426                 zone_start_pfn += size;
4427         }
4428 }
4429 
4430 static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
4431 {
4432         /* Skip empty nodes */
4433         if (!pgdat->node_spanned_pages)
4434                 return;
4435 
4436 #ifdef CONFIG_FLAT_NODE_MEM_MAP
4437         /* ia64 gets its own node_mem_map, before this, without bootmem */
4438         if (!pgdat->node_mem_map) {
4439                 unsigned long size, start, end;
4440                 struct page *map;
4441 
4442                 /*
4443                  * The zone's endpoints aren't required to be MAX_ORDER
4444                  * aligned but the node_mem_map endpoints must be in order
4445                  * for the buddy allocator to function correctly.
4446                  */
4447                 start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
4448                 end = pgdat->node_start_pfn + pgdat->node_spanned_pages;
4449                 end = ALIGN(end, MAX_ORDER_NR_PAGES);
4450                 size =  (end - start) * sizeof(struct page);
4451                 map = alloc_remap(pgdat->node_id, size);
4452                 if (!map)
4453                         map = alloc_bootmem_node_nopanic(pgdat, size);
4454                 pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
4455         }
4456 #ifndef CONFIG_NEED_MULTIPLE_NODES
4457         /*
4458          * With no DISCONTIG, the global mem_map is just set as node 0's
4459          */
4460         if (pgdat == NODE_DATA(0)) {
4461                 mem_map = NODE_DATA(0)->node_mem_map;
4462 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
4463                 if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
4464                         mem_map -= (pgdat->node_start_pfn - ARCH_PFN_OFFSET);
4465 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
4466         }
4467 #endif
4468 #endif /* CONFIG_FLAT_NODE_MEM_MAP */
4469 }
4470 
4471 void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
4472                 unsigned long node_start_pfn, unsigned long *zholes_size)
4473 {
4474         pg_data_t *pgdat = NODE_DATA(nid);
4475 
4476         pgdat->node_id = nid;
4477         pgdat->node_start_pfn = node_start_pfn;
4478         calculate_node_totalpages(pgdat, zones_size, zholes_size);
4479 
4480         alloc_node_mem_map(pgdat);
4481 #ifdef CONFIG_FLAT_NODE_MEM_MAP
4482         printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
4483                 nid, (unsigned long)pgdat,
4484                 (unsigned long)pgdat->node_mem_map);
4485 #endif
4486 
4487         free_area_init_core(pgdat, zones_size, zholes_size);
4488 }
4489 
4490 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
4491 
4492 #if MAX_NUMNODES > 1
4493 /*
4494  * Figure out the number of possible node ids.
4495  */
4496 static void __init setup_nr_node_ids(void)
4497 {
4498         unsigned int node;
4499         unsigned int highest = 0;
4500 
4501         for_each_node_mask(node, node_possible_map)
4502                 highest = node;
4503         nr_node_ids = highest + 1;
4504 }
4505 #else
4506 static inline void setup_nr_node_ids(void)
4507 {
4508 }
4509 #endif
4510 
4511 /**
4512  * add_active_range - Register a range of PFNs backed by physical memory
4513  * @nid: The node ID the range resides on
4514  * @start_pfn: The start PFN of the available physical memory
4515  * @end_pfn: The end PFN of the available physical memory
4516  *
4517  * These ranges are stored in an early_node_map[] and later used by
4518  * free_area_init_nodes() to calculate zone sizes and holes. If the
4519  * range spans a memory hole, it is up to the architecture to ensure
4520  * the memory is not freed by the bootmem allocator. If possible
4521  * the range being registered will be merged with existing ranges.
4522  */
4523 void __init add_active_range(unsigned int nid, unsigned long start_pfn,
4524                                                 unsigned long end_pfn)
4525 {
4526         int i;
4527 
4528         mminit_dprintk(MMINIT_TRACE, "memory_register",
4529                         "Entering add_active_range(%d, %#lx, %#lx) "
4530                         "%d entries of %d used\n",
4531                         nid, start_pfn, end_pfn,
4532                         nr_nodemap_entries, MAX_ACTIVE_REGIONS);
4533 
4534         mminit_validate_memmodel_limits(&start_pfn, &end_pfn);
4535 
4536         /* Merge with existing active regions if possible */
4537         for (i = 0; i < nr_nodemap_entries; i++) {
4538                 if (early_node_map[i].nid != nid)
4539                         continue;
4540 
4541                 /* Skip if an existing region covers this new one */
4542                 if (start_pfn >= early_node_map[i].start_pfn &&
4543                                 end_pfn <= early_node_map[i].end_pfn)
4544                         return;
4545 
4546                 /* Merge forward if suitable */
4547                 if (start_pfn <= early_node_map[i].end_pfn &&
4548                                 end_pfn > early_node_map[i].end_pfn) {
4549                         early_node_map[i].end_pfn = end_pfn;
4550                         return;
4551                 }
4552 
4553                 /* Merge backward if suitable */
4554                 if (start_pfn < early_node_map[i].start_pfn &&
4555                                 end_pfn >= early_node_map[i].start_pfn) {
4556                         early_node_map[i].start_pfn = start_pfn;
4557                         return;
4558                 }
4559         }
4560 
4561         /* Check that early_node_map is large enough */
4562         if (i >= MAX_ACTIVE_REGIONS) {
4563                 printk(KERN_CRIT "More than %d memory regions, truncating\n",
4564                                                         MAX_ACTIVE_REGIONS);
4565                 return;
4566         }
4567 
4568         early_node_map[i].nid = nid;
4569         early_node_map[i].start_pfn = start_pfn;
4570         early_node_map[i].end_pfn = end_pfn;
4571         nr_nodemap_entries = i + 1;
4572 }
4573 
4574 /**
4575  * remove_active_range - Shrink an existing registered range of PFNs
4576  * @nid: The node id the range is on that should be shrunk
4577  * @start_pfn: The new PFN of the range
4578  * @end_pfn: The new PFN of the range
4579  *
4580  * i386 with NUMA use alloc_remap() to store a node_mem_map on a local node.
4581  * The map is kept near the end physical page range that has already been
4582  * registered. This function allows an arch to shrink an existing registered
4583  * range.
4584  */
4585 void __init remove_active_range(unsigned int nid, unsigned long start_pfn,
4586                                 unsigned long end_pfn)
4587 {
4588         int i, j;
4589         int removed = 0;
4590 
4591         printk(KERN_DEBUG "remove_active_range (%d, %lu, %lu)\n",
4592                           nid, start_pfn, end_pfn);
4593 
4594         /* Find the old active region end and shrink */
4595         for_each_active_range_index_in_nid(i, nid) {
4596                 if (early_node_map[i].start_pfn >= start_pfn &&
4597                     early_node_map[i].end_pfn <= end_pfn) {
4598                         /* clear it */
4599                         early_node_map[i].start_pfn = 0;
4600                         early_node_map[i].end_pfn = 0;
4601                         removed = 1;
4602                         continue;
4603                 }
4604                 if (early_node_map[i].start_pfn < start_pfn &&
4605                     early_node_map[i].end_pfn > start_pfn) {
4606                         unsigned long temp_end_pfn = early_node_map[i].end_pfn;
4607                         early_node_map[i].end_pfn = start_pfn;
4608                         if (temp_end_pfn > end_pfn)
4609                                 add_active_range(nid, end_pfn, temp_end_pfn);
4610                         continue;
4611                 }
4612                 if (early_node_map[i].start_pfn >= start_pfn &&
4613                     early_node_map[i].end_pfn > end_pfn &&
4614                     early_node_map[i].start_pfn < end_pfn) {
4615                         early_node_map[i].start_pfn = end_pfn;
4616                         continue;
4617                 }
4618         }
4619 
4620         if (!removed)
4621                 return;
4622 
4623         /* remove the blank ones */
4624         for (i = nr_nodemap_entries - 1; i > 0; i--) {
4625                 if (early_node_map[i].nid != nid)
4626                         continue;
4627                 if (early_node_map[i].end_pfn)
4628                         continue;
4629                 /* we found it, get rid of it */
4630                 for (j = i; j < nr_nodemap_entries - 1; j++)
4631                         memcpy(&early_node_map[j], &early_node_map[j+1],
4632                                 sizeof(early_node_map[j]));
4633                 j = nr_nodemap_entries - 1;
4634                 memset(&early_node_map[j], 0, sizeof(early_node_map[j]));
4635                 nr_nodemap_entries--;
4636         }
4637 }
4638 
4639 /**
4640  * remove_all_active_ranges - Remove all currently registered regions
4641  *
4642  * During discovery, it may be found that a table like SRAT is invalid
4643  * and an alternative discovery method must be used. This function removes
4644  * all currently registered regions.
4645  */
4646 void __init remove_all_active_ranges(void)
4647 {
4648         memset(early_node_map, 0, sizeof(early_node_map));
4649         nr_nodemap_entries = 0;
4650 }
4651 
4652 /* Compare two active node_active_regions */
4653 static int __init cmp_node_active_region(const void *a, const void *b)
4654 {
4655         struct node_active_region *arange = (struct node_active_region *)a;
4656         struct node_active_region *brange = (struct node_active_region *)b;
4657 
4658         /* Done this way to avoid overflows */
4659         if (arange->start_pfn > brange->start_pfn)
4660                 return 1;
4661         if (arange->start_pfn < brange->start_pfn)
4662                 return -1;
4663 
4664         return 0;
4665 }
4666 
4667 /* sort the node_map by start_pfn */
4668 void __init sort_node_map(void)
4669 {
4670         sort(early_node_map, (size_t)nr_nodemap_entries,
4671                         sizeof(struct node_active_region),
4672                         cmp_node_active_region, NULL);
4673 }
4674 
4675 /* Find the lowest pfn for a node */
4676 static unsigned long __init find_min_pfn_for_node(int nid)
4677 {
4678         int i;
4679         unsigned long min_pfn = ULONG_MAX;
4680 
4681         /* Assuming a sorted map, the first range found has the starting pfn */
4682         for_each_active_range_index_in_nid(i, nid)
4683                 min_pfn = min(min_pfn, early_node_map[i].start_pfn);
4684 
4685         if (min_pfn == ULONG_MAX) {
4686                 printk(KERN_WARNING
4687                         "Could not find start_pfn for node %d\n", nid);
4688                 return 0;
4689         }
4690 
4691         return min_pfn;
4692 }
4693 
4694 /**
4695  * find_min_pfn_with_active_regions - Find the minimum PFN registered
4696  *
4697  * It returns the minimum PFN based on information provided via
4698  * add_active_range().
4699  */
4700 unsigned long __init find_min_pfn_with_active_regions(void)
4701 {
4702         return find_min_pfn_for_node(MAX_NUMNODES);
4703 }
4704 
4705 /*
4706  * early_calculate_totalpages()
4707  * Sum pages in active regions for movable zone.
4708  * Populate N_HIGH_MEMORY for calculating usable_nodes.
4709  */
4710 static unsigned long __init early_calculate_totalpages(void)
4711 {
4712         int i;
4713         unsigned long totalpages = 0;
4714 
4715         for (i = 0; i < nr_nodemap_entries; i++) {
4716                 unsigned long pages = early_node_map[i].end_pfn -
4717                                                 early_node_map[i].start_pfn;
4718                 totalpages += pages;
4719                 if (pages)
4720                         node_set_state(early_node_map[i].nid, N_HIGH_MEMORY);
4721         }
4722         return totalpages;
4723 }
4724 
4725 /*
4726  * Find the PFN the Movable zone begins in each node. Kernel memory
4727  * is spread evenly between nodes as long as the nodes have enough
4728  * memory. When they don't, some nodes will have more kernelcore than
4729  * others
4730  */
4731 static void __init find_zone_movable_pfns_for_nodes(unsigned long *movable_pfn)
4732 {
4733         int i, nid;
4734         unsigned long usable_startpfn;
4735         unsigned long kernelcore_node, kernelcore_remaining;
4736         /* save the state before borrow the nodemask */
4737         nodemask_t saved_node_state = node_states[N_HIGH_MEMORY];
4738         unsigned long totalpages = early_calculate_totalpages();
4739         int usable_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
4740 
4741         /*
4742          * If movablecore was specified, calculate what size of
4743          * kernelcore that corresponds so that memory usable for
4744          * any allocation type is evenly spread. If both kernelcore
4745          * and movablecore are specified, then the value of kernelcore
4746          * will be used for required_kernelcore if it's greater than
4747          * what movablecore would have allowed.
4748          */
4749         if (required_movablecore) {
4750                 unsigned long corepages;
4751 
4752                 /*
4753                  * Round-up so that ZONE_MOVABLE is at least as large as what
4754                  * was requested by the user
4755                  */
4756                 required_movablecore =
4757                         roundup(required_movablecore, MAX_ORDER_NR_PAGES);
4758                 corepages = totalpages - required_movablecore;
4759 
4760                 required_kernelcore = max(required_kernelcore, corepages);
4761         }
4762 
4763         /* If kernelcore was not specified, there is no ZONE_MOVABLE */
4764         if (!required_kernelcore)
4765                 goto out;
4766 
4767         /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
4768         find_usable_zone_for_movable();
4769         usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
4770 
4771 restart:
4772         /* Spread kernelcore memory as evenly as possible throughout nodes */
4773         kernelcore_node = required_kernelcore / usable_nodes;
4774         for_each_node_state(nid, N_HIGH_MEMORY) {
4775                 /*
4776                  * Recalculate kernelcore_node if the division per node
4777                  * now exceeds what is necessary to satisfy the requested
4778                  * amount of memory for the kernel
4779                  */
4780                 if (required_kernelcore < kernelcore_node)
4781                         kernelcore_node = required_kernelcore / usable_nodes;
4782 
4783                 /*
4784                  * As the map is walked, we track how much memory is usable
4785                  * by the kernel using kernelcore_remaining. When it is
4786                  * 0, the rest of the node is usable by ZONE_MOVABLE
4787                  */
4788                 kernelcore_remaining = kernelcore_node;
4789 
4790                 /* Go through each range of PFNs within this node */
4791                 for_each_active_range_index_in_nid(i, nid) {
4792                         unsigned long start_pfn, end_pfn;
4793                         unsigned long size_pages;
4794 
4795                         start_pfn = max(early_node_map[i].start_pfn,
4796                                                 zone_movable_pfn[nid]);
4797                         end_pfn = early_node_map[i].end_pfn;
4798                         if (start_pfn >= end_pfn)
4799                                 continue;
4800 
4801                         /* Account for what is only usable for kernelcore */
4802                         if (start_pfn < usable_startpfn) {
4803                                 unsigned long kernel_pages;
4804                                 kernel_pages = min(end_pfn, usable_startpfn)
4805                                                                 - start_pfn;
4806 
4807                                 kernelcore_remaining -= min(kernel_pages,
4808                                                         kernelcore_remaining);
4809                                 required_kernelcore -= min(kernel_pages,
4810                                                         required_kernelcore);
4811 
4812                                 /* Continue if range is now fully accounted */
4813                                 if (end_pfn <= usable_startpfn) {
4814 
4815                                         /*
4816                                          * Push zone_movable_pfn to the end so
4817                                          * that if we have to rebalance
4818                                          * kernelcore across nodes, we will
4819                                          * not double account here
4820                                          */
4821                                         zone_movable_pfn[nid] = end_pfn;
4822                                         continue;
4823                                 }
4824                                 start_pfn = usable_startpfn;
4825                         }
4826 
4827                         /*
4828                          * The usable PFN range for ZONE_MOVABLE is from
4829                          * start_pfn->end_pfn. Calculate size_pages as the
4830                          * number of pages used as kernelcore
4831                          */
4832                         size_pages = end_pfn - start_pfn;
4833                         if (size_pages > kernelcore_remaining)
4834                                 size_pages = kernelcore_remaining;
4835                         zone_movable_pfn[nid] = start_pfn + size_pages;
4836 
4837                         /*
4838                          * Some kernelcore has been met, update counts and
4839                          * break if the kernelcore for this node has been
4840                          * satisified
4841                          */
4842                         required_kernelcore -= min(required_kernelcore,
4843                                                                 size_pages);
4844                         kernelcore_remaining -= size_pages;
4845                         if (!kernelcore_remaining)
4846                                 break;
4847                 }
4848         }
4849 
4850         /*
4851          * If there is still required_kernelcore, we do another pass with one
4852          * less node in the count. This will push zone_movable_pfn[nid] further
4853          * along on the nodes that still have memory until kernelcore is
4854          * satisified
4855          */
4856         usable_nodes--;
4857         if (usable_nodes && required_kernelcore > usable_nodes)
4858                 goto restart;
4859 
4860         /* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
4861         for (nid = 0; nid < MAX_NUMNODES; nid++)
4862                 zone_movable_pfn[nid] =
4863                         roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
4864 
4865 out:
4866         /* restore the node_state */
4867         node_states[N_HIGH_MEMORY] = saved_node_state;
4868 }
4869 
4870 /* Any regular memory on that node ? */
4871 static void check_for_regular_memory(pg_data_t *pgdat)
4872 {
4873 #ifdef CONFIG_HIGHMEM
4874         enum zone_type zone_type;
4875 
4876         for (zone_type = 0; zone_type <= ZONE_NORMAL; zone_type++) {
4877                 struct zone *zone = &pgdat->node_zones[zone_type];
4878                 if (zone->present_pages)
4879                         node_set_state(zone_to_nid(zone), N_NORMAL_MEMORY);
4880         }
4881 #endif
4882 }
4883 
4884 /**
4885  * free_area_init_nodes - Initialise all pg_data_t and zone data
4886  * @max_zone_pfn: an array of max PFNs for each zone
4887  *
4888  * This will call free_area_init_node() for each active node in the system.
4889  * Using the page ranges provided by add_active_range(), the size of each
4890  * zone in each node and their holes is calculated. If the maximum PFN
4891  * between two adjacent zones match, it is assumed that the zone is empty.
4892  * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
4893  * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
4894  * starts where the previous one ended. For example, ZONE_DMA32 starts
4895  * at arch_max_dma_pfn.
4896  */
4897 void __init free_area_init_nodes(unsigned long *max_zone_pfn)
4898 {
4899         unsigned long nid;
4900         int i;
4901 
4902         /* Sort early_node_map as initialisation assumes it is sorted */
4903         sort_node_map();
4904 
4905         /* Record where the zone boundaries are */
4906         memset(arch_zone_lowest_possible_pfn, 0,
4907                                 sizeof(arch_zone_lowest_possible_pfn));
4908         memset(arch_zone_highest_possible_pfn, 0,
4909                                 sizeof(arch_zone_highest_possible_pfn));
4910         arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
4911         arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
4912         for (i = 1; i < MAX_NR_ZONES; i++) {
4913                 if (i == ZONE_MOVABLE)
4914                         continue;
4915                 arch_zone_lowest_possible_pfn[i] =
4916                         arch_zone_highest_possible_pfn[i-1];
4917                 arch_zone_highest_possible_pfn[i] =
4918                         max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
4919         }
4920         arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
4921         arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
4922 
4923         /* Find the PFNs that ZONE_MOVABLE begins at in each node */
4924         memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
4925         find_zone_movable_pfns_for_nodes(zone_movable_pfn);
4926 
4927         /* Print out the zone ranges */
4928         printk("Zone PFN ranges:\n");
4929         for (i = 0; i < MAX_NR_ZONES; i++) {
4930                 if (i == ZONE_MOVABLE)
4931                         continue;
4932                 printk("  %-8s ", zone_names[i]);
4933                 if (arch_zone_lowest_possible_pfn[i] ==
4934                                 arch_zone_highest_possible_pfn[i])
4935                         printk("empty\n");
4936                 else
4937                         printk("%0#10lx -> %0#10lx\n",
4938                                 arch_zone_lowest_possible_pfn[i],
4939                                 arch_zone_highest_possible_pfn[i]);
4940         }
4941 
4942         /* Print out the PFNs ZONE_MOVABLE begins at in each node */
4943         printk("Movable zone start PFN for each node\n");
4944         for (i = 0; i < MAX_NUMNODES; i++) {
4945                 if (zone_movable_pfn[i])
4946                         printk("  Node %d: %lu\n", i, zone_movable_pfn[i]);
4947         }
4948 
4949         /* Print out the early_node_map[] */
4950         printk("early_node_map[%d] active PFN ranges\n", nr_nodemap_entries);
4951         for (i = 0; i < nr_nodemap_entries; i++)
4952                 printk("  %3d: %0#10lx -> %0#10lx\n", early_node_map[i].nid,
4953                                                 early_node_map[i].start_pfn,
4954                                                 early_node_map[i].end_pfn);
4955 
4956         /* Initialise every node */
4957         mminit_verify_pageflags_layout();
4958         setup_nr_node_ids();
4959         for_each_online_node(nid) {
4960                 pg_data_t *pgdat = NODE_DATA(nid);
4961                 free_area_init_node(nid, NULL,
4962                                 find_min_pfn_for_node(nid), NULL);
4963 
4964                 /* Any memory on that node */
4965                 if (pgdat->node_present_pages)
4966                         node_set_state(nid, N_HIGH_MEMORY);
4967                 check_for_regular_memory(pgdat);
4968         }
4969 }
4970 
4971 static int __init cmdline_parse_core(char *p, unsigned long *core)
4972 {
4973         unsigned long long coremem;
4974         if (!p)
4975                 return -EINVAL;
4976 
4977         coremem = memparse(p, &p);
4978         *core = coremem >> PAGE_SHIFT;
4979 
4980         /* Paranoid check that UL is enough for the coremem value */
4981         WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
4982 
4983         return 0;
4984 }
4985 
4986 /*
4987  * kernelcore=size sets the amount of memory for use for allocations that
4988  * cannot be reclaimed or migrated.
4989  */
4990 static int __init cmdline_parse_kernelcore(char *p)
4991 {
4992         return cmdline_parse_core(p, &required_kernelcore);
4993 }
4994 
4995 /*
4996  * movablecore=size sets the amount of memory for use for allocations that
4997  * can be reclaimed or migrated.
4998  */
4999 static int __init cmdline_parse_movablecore(char *p)
5000 {
5001         return cmdline_parse_core(p, &required_movablecore);
5002 }
5003 
5004 early_param("kernelcore", cmdline_parse_kernelcore);
5005 early_param("movablecore", cmdline_parse_movablecore);
5006 
5007 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
5008 
5009 /**
5010  * set_dma_reserve - set the specified number of pages reserved in the first zone
5011  * @new_dma_reserve: The number of pages to mark reserved
5012  *
5013  * The per-cpu batchsize and zone watermarks are determined by present_pages.
5014  * In the DMA zone, a significant percentage may be consumed by kernel image
5015  * and other unfreeable allocations which can skew the watermarks badly. This
5016  * function may optionally be used to account for unfreeable pages in the
5017  * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
5018  * smaller per-cpu batchsize.
5019  */
5020 void __init set_dma_reserve(unsigned long new_dma_reserve)
5021 {
5022         dma_reserve = new_dma_reserve;
5023 }
5024 
5025 void __init free_area_init(unsigned long *zones_size)
5026 {
5027         free_area_init_node(0, zones_size,
5028                         __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
5029 }
5030 
5031 static int page_alloc_cpu_notify(struct notifier_block *self,
5032                                  unsigned long action, void *hcpu)
5033 {
5034         int cpu = (unsigned long)hcpu;
5035 
5036         if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
5037                 drain_pages(cpu);
5038 
5039                 /*
5040                  * Spill the event counters of the dead processor
5041                  * into the current processors event counters.
5042                  * This artificially elevates the count of the current
5043                  * processor.
5044                  */
5045                 vm_events_fold_cpu(cpu);
5046 
5047                 /*
5048                  * Zero the differential counters of the dead processor
5049                  * so that the vm statistics are consistent.
5050                  *
5051                  * This is only okay since the processor is dead and cannot
5052                  * race with what we are doing.
5053                  */
5054                 refresh_cpu_vm_stats(cpu);
5055         }
5056         return NOTIFY_OK;
5057 }
5058 
5059 void __init page_alloc_init(void)
5060 {
5061         hotcpu_notifier(page_alloc_cpu_notify, 0);
5062 }
5063 
5064 /*
5065  * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
5066  *      or min_free_kbytes changes.
5067  */
5068 static void calculate_totalreserve_pages(void)
5069 {
5070         struct pglist_data *pgdat;
5071         unsigned long reserve_pages = 0;
5072         enum zone_type i, j;
5073 
5074         for_each_online_pgdat(pgdat) {
5075                 for (i = 0; i < MAX_NR_ZONES; i++) {
5076                         struct zone *zone = pgdat->node_zones + i;
5077                         unsigned long max = 0;
5078 
5079                         /* Find valid and maximum lowmem_reserve in the zone */
5080                         for (j = i; j < MAX_NR_ZONES; j++) {
5081                                 if (zone->lowmem_reserve[j] > max)
5082                                         max = zone->lowmem_reserve[j];
5083                         }
5084 
5085                         /* we treat the high watermark as reserved pages. */
5086                         max += high_wmark_pages(zone);
5087 
5088                         if (max > zone->present_pages)
5089                                 max = zone->present_pages;
5090                         reserve_pages += max;
5091                 }
5092         }
5093         totalreserve_pages = reserve_pages;
5094 }
5095 
5096 /*
5097  * setup_per_zone_lowmem_reserve - called whenever
5098  *      sysctl_lower_zone_reserve_ratio changes.  Ensures that each zone
5099  *      has a correct pages reserved value, so an adequate number of
5100  *      pages are left in the zone after a successful __alloc_pages().
5101  */
5102 static void setup_per_zone_lowmem_reserve(void)
5103 {
5104         struct pglist_data *pgdat;
5105         enum zone_type j, idx;
5106 
5107         for_each_online_pgdat(pgdat) {
5108                 for (j = 0; j < MAX_NR_ZONES; j++) {
5109                         struct zone *zone = pgdat->node_zones + j;
5110                         unsigned long present_pages = zone->present_pages;
5111 
5112                         zone->lowmem_reserve[j] = 0;
5113 
5114                         idx = j;
5115                         while (idx) {
5116                                 struct zone *lower_zone;
5117 
5118                                 idx--;
5119 
5120                                 if (sysctl_lowmem_reserve_ratio[idx] < 1)
5121                                         sysctl_lowmem_reserve_ratio[idx] = 1;
5122 
5123                                 lower_zone = pgdat->node_zones + idx;
5124                                 lower_zone->lowmem_reserve[j] = present_pages /
5125                                         sysctl_lowmem_reserve_ratio[idx];
5126                                 present_pages += lower_zone->present_pages;
5127                         }
5128                 }
5129         }
5130 
5131         /* update totalreserve_pages */
5132         calculate_totalreserve_pages();
5133 }
5134 
5135 /**
5136  * setup_per_zone_wmarks - called when min_free_kbytes changes
5137  * or when memory is hot-{added|removed}
5138  *
5139  * Ensures that the watermark[min,low,high] values for each zone are set
5140  * correctly with respect to min_free_kbytes.
5141  */
5142 void setup_per_zone_wmarks(void)
5143 {
5144         unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
5145         unsigned long lowmem_pages = 0;
5146         struct zone *zone;
5147         unsigned long flags;
5148 
5149         /* Calculate total number of !ZONE_HIGHMEM pages */
5150         for_each_zone(zone) {
5151                 if (!is_highmem(zone))
5152                         lowmem_pages += zone->present_pages;
5153         }
5154 
5155         for_each_zone(zone) {
5156                 u64 tmp;
5157 
5158                 spin_lock_irqsave(&zone->lock, flags);
5159                 tmp = (u64)pages_min * zone->present_pages;
5160                 do_div(tmp, lowmem_pages);
5161                 if (is_highmem(zone)) {
5162                         /*
5163                          * __GFP_HIGH and PF_MEMALLOC allocations usually don't
5164                          * need highmem pages, so cap pages_min to a small
5165                          * value here.
5166                          *
5167                          * The WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
5168                          * deltas controls asynch page reclaim, and so should
5169                          * not be capped for highmem.
5170                          */
5171                         int min_pages;
5172 
5173                         min_pages = zone->present_pages / 1024;
5174                         if (min_pages < SWAP_CLUSTER_MAX)
5175                                 min_pages = SWAP_CLUSTER_MAX;
5176                         if (min_pages > 128)
5177                                 min_pages = 128;
5178                         zone->watermark[WMARK_MIN] = min_pages;
5179                 } else {
5180                         /*
5181                          * If it's a lowmem zone, reserve a number of pages
5182                          * proportionate to the zone's size.
5183                          */
5184                         zone->watermark[WMARK_MIN] = tmp;
5185                 }
5186 
5187                 zone->watermark[WMARK_LOW]  = min_wmark_pages(zone) + (tmp >> 2);
5188                 zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
5189                 setup_zone_migrate_reserve(zone);
5190                 spin_unlock_irqrestore(&zone->lock, flags);
5191         }
5192 
5193         /* update totalreserve_pages */
5194         calculate_totalreserve_pages();
5195 }
5196 
5197 /*
5198  * The inactive anon list should be small enough that the VM never has to
5199  * do too much work, but large enough that each inactive page has a chance
5200  * to be referenced again before it is swapped out.
5201  *
5202  * The inactive_anon ratio is the target ratio of ACTIVE_ANON to
5203  * INACTIVE_ANON pages on this zone's LRU, maintained by the
5204  * pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
5205  * the anonymous pages are kept on the inactive list.
5206  *
5207  * total     target    max
5208  * memory    ratio     inactive anon
5209  * -------------------------------------
5210  *   10MB       1         5MB
5211  *  100MB       1        50MB
5212  *    1GB       3       250MB
5213  *   10GB      10       0.9GB
5214  *  100GB      31         3GB
5215  *    1TB     101        10GB
5216  *   10TB     320        32GB
5217  */
5218 static void __meminit calculate_zone_inactive_ratio(struct zone *zone)
5219 {
5220         unsigned int gb, ratio;
5221 
5222         /* Zone size in gigabytes */
5223         gb = zone->present_pages >> (30 - PAGE_SHIFT);
5224         if (gb)
5225                 ratio = int_sqrt(10 * gb);
5226         else
5227                 ratio = 1;
5228 
5229         zone->inactive_ratio = ratio;
5230 }
5231 
5232 static void __meminit setup_per_zone_inactive_ratio(void)
5233 {
5234         struct zone *zone;
5235 
5236         for_each_zone(zone)
5237                 calculate_zone_inactive_ratio(zone);
5238 }
5239 
5240 /*
5241  * Initialise min_free_kbytes.
5242  *
5243  * For small machines we want it small (128k min).  For large machines
5244  * we want it large (64MB max).  But it is not linear, because network
5245  * bandwidth does not increase linearly with machine size.  We use
5246  *
5247  *      min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
5248  *      min_free_kbytes = sqrt(lowmem_kbytes * 16)
5249  *
5250  * which yields
5251  *
5252  * 16MB:        512k
5253  * 32MB:        724k
5254  * 64MB:        1024k
5255  * 128MB:       1448k
5256  * 256MB:       2048k
5257  * 512MB:       2896k
5258  * 1024MB:      4096k
5259  * 2048MB:      5792k
5260  * 4096MB:      8192k
5261  * 8192MB:      11584k
5262  * 16384MB:     16384k
5263  */
5264 int __meminit init_per_zone_wmark_min(void)
5265 {
5266         unsigned long lowmem_kbytes;
5267 
5268         lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
5269 
5270         min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
5271         if (min_free_kbytes < 128)
5272                 min_free_kbytes = 128;
5273         if (min_free_kbytes > 65536)
5274                 min_free_kbytes = 65536;
5275         setup_per_zone_wmarks();
5276         refresh_zone_stat_thresholds();
5277         setup_per_zone_lowmem_reserve();
5278         setup_per_zone_inactive_ratio();
5279         return 0;
5280 }
5281 module_init(init_per_zone_wmark_min)
5282 
5283 /*
5284  * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so 
5285  *      that we can call two helper functions whenever min_free_kbytes
5286  *      changes.
5287  */
5288 int min_free_kbytes_sysctl_handler(ctl_table *table, int write, 
5289         void __user *buffer, size_t *length, loff_t *ppos)
5290 {
5291         proc_dointvec(table, write, buffer, length, ppos);
5292         if (write)
5293                 setup_per_zone_wmarks();
5294         return 0;
5295 }
5296 
5297 #ifdef CONFIG_NUMA
5298 int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
5299         void __user *buffer, size_t *length, loff_t *ppos)
5300 {
5301         struct zone *zone;
5302         int rc;
5303 
5304         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5305         if (rc)
5306                 return rc;
5307 
5308         for_each_zone(zone)
5309                 zone->min_unmapped_pages = (zone->present_pages *
5310                                 sysctl_min_unmapped_ratio) / 100;
5311         return 0;
5312 }
5313 
5314 int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
5315         void __user *buffer, size_t *length, loff_t *ppos)
5316 {
5317         struct zone *zone;
5318         int rc;
5319 
5320         rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
5321         if (rc)
5322                 return rc;
5323 
5324         for_each_zone(zone)
5325                 zone->min_slab_pages = (zone->present_pages *
5326                                 sysctl_min_slab_ratio) / 100;
5327         return 0;
5328 }
5329 #endif
5330 
5331 /*
5332  * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
5333  *      proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
5334  *      whenever sysctl_lowmem_reserve_ratio changes.
5335  *
5336  * The reserve ratio obviously has absolutely no relation with the
5337  * minimum watermarks. The lowmem reserve ratio can only make sense
5338  * if in function of the boot time zone sizes.
5339  */
5340 int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
5341         void __user *buffer, size_t *length, loff_t *ppos)
5342 {
5343         proc_dointvec_minmax(table, write, buffer, length, ppos);
5344         setup_per_zone_lowmem_reserve();
5345         return 0;
5346 }
5347 
5348 /*
5349  * percpu_pagelist_fraction - changes the pcp->high for each zone on each
5350  * cpu.  It is the fraction of total pages in each zone that a hot per cpu pagelist
5351  * can have before it gets flushed back to buddy allocator.
5352  */
5353 
5354 int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
5355         void __user *buffer, size_t *length, loff_t *ppos)
5356 {
5357         struct zone *zone;
5358         unsigned int cpu;
5359         int ret;
5360 
5361         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
5362         if (!write || (ret == -EINVAL))
5363                 return ret;
5364         for_each_populated_zone(zone) {
5365                 for_each_possible_cpu(cpu) {
5366                         unsigned long  high;
5367                         high = zone->present_pages / percpu_pagelist_fraction;
5368                         setup_pagelist_highmark(
5369                                 per_cpu_ptr(zone->pageset, cpu), high);
5370                 }
5371         }
5372         return 0;
5373 }
5374 
5375 int hashdist = HASHDIST_DEFAULT;
5376 
5377 #ifdef CONFIG_NUMA
5378 static int __init set_hashdist(char *str)
5379 {
5380         if (!str)
5381                 return 0;
5382         hashdist = simple_strtoul(str, &str, 0);
5383         return 1;
5384 }
5385 __setup("hashdist=", set_hashdist);
5386 #endif
5387 
5388 /*
5389  * allocate a large system hash table from bootmem
5390  * - it is assumed that the hash table must contain an exact power-of-2
5391  *   quantity of entries
5392  * - limit is the number of hash buckets, not the total allocation size
5393  */
5394 void *__init alloc_large_system_hash(const char *tablename,
5395                                      unsigned long bucketsize,
5396                                      unsigned long numentries,
5397                                      int scale,
5398                                      int flags,
5399                                      unsigned int *_hash_shift,
5400                                      unsigned int *_hash_mask,
5401                                      unsigned long limit)
5402 {
5403         unsigned long long max = limit;
5404         unsigned long log2qty, size;
5405         void *table = NULL;
5406 
5407         /* allow the kernel cmdline to have a say */
5408         if (!numentries) {
5409                 /* round applicable memory size up to nearest megabyte */
5410                 numentries = nr_kernel_pages;
5411                 numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
5412                 numentries >>= 20 - PAGE_SHIFT;
5413                 numentries <<= 20 - PAGE_SHIFT;
5414 
5415                 /* limit to 1 bucket per 2^scale bytes of low memory */
5416                 if (scale > PAGE_SHIFT)
5417                         numentries >>= (scale - PAGE_SHIFT);
5418                 else
5419                         numentries <<= (PAGE_SHIFT - scale);
5420 
5421                 /* Make sure we've got at least a 0-order allocation.. */
5422                 if (unlikely(flags & HASH_SMALL)) {
5423                         /* Makes no sense without HASH_EARLY */
5424                         WARN_ON(!(flags & HASH_EARLY));
5425                         if (!(numentries >> *_hash_shift)) {
5426                                 numentries = 1UL << *_hash_shift;
5427                                 BUG_ON(!numentries);
5428                         }
5429                 } else if (unlikely((numentries * bucketsize) < PAGE_SIZE))
5430                         numentries = PAGE_SIZE / bucketsize;
5431         }
5432         numentries = roundup_pow_of_two(numentries);
5433 
5434         /* limit allocation size to 1/16 total memory by default */
5435         if (max == 0) {
5436                 max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
5437                 do_div(max, bucketsize);
5438         }
5439 
5440         if (numentries > max)
5441                 numentries = max;
5442 
5443         log2qty = ilog2(numentries);
5444 
5445         do {
5446                 size = bucketsize << log2qty;
5447                 if (flags & HASH_EARLY)
5448                         table = alloc_bootmem_nopanic(size);
5449                 else if (hashdist)
5450                         table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
5451                 else {
5452                         /*
5453                          * If bucketsize is not a power-of-two, we may free
5454                          * some pages at the end of hash table which
5455                          * alloc_pages_exact() automatically does
5456                          */
5457                         if (get_order(size) < MAX_ORDER) {
5458                                 table = alloc_pages_exact(size, GFP_ATOMIC);
5459                                 kmemleak_alloc(table, size, 1, GFP_ATOMIC);
5460                         }
5461                 }
5462         } while (!table && size > PAGE_SIZE && --log2qty);
5463 
5464         if (!table)
5465                 panic("Failed to allocate %s hash table\n", tablename);
5466 
5467         printk(KERN_INFO "%s hash table entries: %ld (order: %d, %lu bytes)\n",
5468                tablename,
5469                (1UL << log2qty),
5470                ilog2(size) - PAGE_SHIFT,
5471                size);
5472 
5473         if (_hash_shift)
5474                 *_hash_shift = log2qty;
5475         if (_hash_mask)
5476                 *_hash_mask = (1 << log2qty) - 1;
5477 
5478         return table;
5479 }
5480 
5481 /* Return a pointer to the bitmap storing bits affecting a block of pages */
5482 static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
5483                                                         unsigned long pfn)
5484 {
5485 #ifdef CONFIG_SPARSEMEM
5486         return __pfn_to_section(pfn)->pageblock_flags;
5487 #else
5488         return zone->pageblock_flags;
5489 #endif /* CONFIG_SPARSEMEM */
5490 }
5491 
5492 static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
5493 {
5494 #ifdef CONFIG_SPARSEMEM
5495         pfn &= (PAGES_PER_SECTION-1);
5496         return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5497 #else
5498         pfn = pfn - round_down(zone->zone_start_pfn, pageblock_nr_pages);
5499         return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
5500 #endif /* CONFIG_SPARSEMEM */
5501 }
5502 
5503 /**
5504  * get_pageblock_flags_group - Return the requested group of flags for the pageblock_nr_pages block of pages
5505  * @page: The page within the block of interest
5506  * @start_bitidx: The first bit of interest to retrieve
5507  * @end_bitidx: The last bit of interest
5508  * returns pageblock_bits flags
5509  */
5510 unsigned long get_pageblock_flags_group(struct page *page,
5511                                         int start_bitidx, int end_bitidx)
5512 {
5513         struct zone *zone;
5514         unsigned long *bitmap;
5515         unsigned long pfn, bitidx;
5516         unsigned long flags = 0;
5517         unsigned long value = 1;
5518 
5519         zone = page_zone(page);
5520         pfn = page_to_pfn(page);
5521         bitmap = get_pageblock_bitmap(zone, pfn);
5522         bitidx = pfn_to_bitidx(zone, pfn);
5523 
5524         for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5525                 if (test_bit(bitidx + start_bitidx, bitmap))
5526                         flags |= value;
5527 
5528         return flags;
5529 }
5530 
5531 /**
5532  * set_pageblock_flags_group - Set the requested group of flags for a pageblock_nr_pages block of pages
5533  * @page: The page within the block of interest
5534  * @start_bitidx: The first bit of interest
5535  * @end_bitidx: The last bit of interest
5536  * @flags: The flags to set
5537  */
5538 void set_pageblock_flags_group(struct page *page, unsigned long flags,
5539                                         int start_bitidx, int end_bitidx)
5540 {
5541         struct zone *zone;
5542         unsigned long *bitmap;
5543         unsigned long pfn, bitidx;
5544         unsigned long value = 1;
5545 
5546         zone = page_zone(page);
5547         pfn = page_to_pfn(page);
5548         bitmap = get_pageblock_bitmap(zone, pfn);
5549         bitidx = pfn_to_bitidx(zone, pfn);
5550         VM_BUG_ON(pfn < zone->zone_start_pfn);
5551         VM_BUG_ON(pfn >= zone->zone_start_pfn + zone->spanned_pages);
5552 
5553         for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
5554                 if (flags & value)
5555                         __set_bit(bitidx + start_bitidx, bitmap);
5556                 else
5557                         __clear_bit(bitidx + start_bitidx, bitmap);
5558 }
5559 
5560 /*
5561  * This is designed as sub function...plz see page_isolation.c also.
5562  * set/clear page block's type to be ISOLATE.
5563  * page allocater never alloc memory from ISOLATE block.
5564  */
5565 
5566 static int
5567 __count_immobile_pages(struct zone *zone, struct page *page, int count)
5568 {
5569         unsigned long pfn, iter, found;
5570         /*
5571          * For avoiding noise data, lru_add_drain_all() should be called
5572          * If ZONE_MOVABLE, the zone never contains immobile pages
5573          */
5574         if (zone_idx(zone) == ZONE_MOVABLE)
5575                 return true;
5576 
5577         if (get_pageblock_migratetype(page) == MIGRATE_MOVABLE)
5578                 return true;
5579 
5580         pfn = page_to_pfn(page);
5581         for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
5582                 unsigned long check = pfn + iter;
5583 
5584                 if (!pfn_valid_within(check))
5585                         continue;
5586 
5587                 page = pfn_to_page(check);
5588                 if (!page_count(page)) {
5589                         if (PageBuddy(page))
5590                                 iter += (1 << page_order(page)) - 1;
5591                         continue;
5592                 }
5593                 if (!PageLRU(page))
5594                         found++;
5595                 /*
5596                  * If there are RECLAIMABLE pages, we need to check it.
5597                  * But now, memory offline itself doesn't call shrink_slab()
5598                  * and it still to be fixed.
5599                  */
5600                 /*
5601                  * If the page is not RAM, page_count()should be 0.
5602                  * we don't need more check. This is an _used_ not-movable page.
5603                  *
5604                  * The problematic thing here is PG_reserved pages. PG_reserved
5605                  * is set to both of a memory hole page and a _used_ kernel
5606                  * page at boot.
5607                  */
5608                 if (found > count)
5609                         return false;
5610         }
5611         return true;
5612 }
5613 
5614 bool is_pageblock_removable_nolock(struct page *page)
5615 {
5616         struct zone *zone = page_zone(page);
5617         unsigned long pfn = page_to_pfn(page);
5618 
5619         /*
5620          * We have to be careful here because we are iterating over memory
5621          * sections which are not zone aware so we might end up outside of
5622          * the zone but still within the section.
5623          */
5624         if (!zone || zone->zone_start_pfn > pfn ||
5625                         zone->zone_start_pfn + zone->spanned_pages <= pfn)
5626                 return false;
5627 
5628         return __count_immobile_pages(zone, page, 0);
5629 }
5630 
5631 int set_migratetype_isolate(struct page *page)
5632 {
5633         struct zone *zone;
5634         unsigned long flags, pfn;
5635         struct memory_isolate_notify arg;
5636         int notifier_ret;
5637         int ret = -EBUSY;
5638 
5639         zone = page_zone(page);
5640 
5641         spin_lock_irqsave(&zone->lock, flags);
5642 
5643         pfn = page_to_pfn(page);
5644         arg.start_pfn = pfn;
5645         arg.nr_pages = pageblock_nr_pages;
5646         arg.pages_found = 0;
5647 
5648         /*
5649          * It may be possible to isolate a pageblock even if the
5650          * migratetype is not MIGRATE_MOVABLE. The memory isolation
5651          * notifier chain is used by balloon drivers to return the
5652          * number of pages in a range that are held by the balloon
5653          * driver to shrink memory. If all the pages are accounted for
5654          * by balloons, are free, or on the LRU, isolation can continue.
5655          * Later, for example, when memory hotplug notifier runs, these
5656          * pages reported as "can be isolated" should be isolated(freed)
5657          * by the balloon driver through the memory notifier chain.
5658          */
5659         notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
5660         notifier_ret = notifier_to_errno(notifier_ret);
5661         if (notifier_ret)
5662                 goto out;
5663         /*
5664          * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
5665          * We just check MOVABLE pages.
5666          */
5667         if (__count_immobile_pages(zone, page, arg.pages_found))
5668                 ret = 0;
5669 
5670         /*
5671          * immobile means "not-on-lru" paes. If immobile is larger than
5672          * removable-by-driver pages reported by notifier, we'll fail.
5673          */
5674 
5675 out:
5676         if (!ret) {
5677                 set_pageblock_migratetype(page, MIGRATE_ISOLATE);
5678                 move_freepages_block(zone, page, MIGRATE_ISOLATE);
5679         }
5680 
5681         spin_unlock_irqrestore(&zone->lock, flags);
5682         if (!ret)
5683                 drain_all_pages();
5684         return ret;
5685 }
5686 
5687 void unset_migratetype_isolate(struct page *page)
5688 {
5689         struct zone *zone;
5690         unsigned long flags;
5691         zone = page_zone(page);
5692         spin_lock_irqsave(&zone->lock, flags);
5693         if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
5694                 goto out;
5695         set_pageblock_migratetype(page, MIGRATE_MOVABLE);
5696         move_freepages_block(zone, page, MIGRATE_MOVABLE);
5697 out:
5698         spin_unlock_irqrestore(&zone->lock, flags);
5699 }
5700 
5701 #ifdef CONFIG_MEMORY_HOTREMOVE
5702 /*
5703  * All pages in the range must be isolated before calling this.
5704  */
5705 void
5706 __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
5707 {
5708         struct page *page;
5709         struct zone *zone;
5710         int order, i;
5711         unsigned long pfn;
5712         unsigned long flags;
5713         /* find the first valid pfn */
5714         for (pfn = start_pfn; pfn < end_pfn; pfn++)
5715                 if (pfn_valid(pfn))
5716                         break;
5717         if (pfn == end_pfn)
5718                 return;
5719         zone = page_zone(pfn_to_page(pfn));
5720         spin_lock_irqsave(&zone->lock, flags);
5721         pfn = start_pfn;
5722         while (pfn < end_pfn) {
5723                 if (!pfn_valid(pfn)) {
5724                         pfn++;
5725                         continue;
5726                 }
5727                 page = pfn_to_page(pfn);
5728                 BUG_ON(page_count(page));
5729                 BUG_ON(!PageBuddy(page));
5730                 order = page_order(page);
5731 #ifdef CONFIG_DEBUG_VM
5732                 printk(KERN_INFO "remove from free list %lx %d %lx\n",
5733                        pfn, 1 << order, end_pfn);
5734 #endif
5735                 list_del(&page->lru);
5736                 rmv_page_order(page);
5737                 zone->free_area[order].nr_free--;
5738                 __mod_zone_page_state(zone, NR_FREE_PAGES,
5739                                       - (1UL << order));
5740 #ifdef CONFIG_HIGHMEM
5741                 if (PageHighMem(page))
5742                         totalhigh_pages -= 1 << order;
5743 #endif
5744                 for (i = 0; i < (1 << order); i++)
5745                         SetPageReserved((page+i));
5746                 pfn += (1 << order);
5747         }
5748         spin_unlock_irqrestore(&zone->lock, flags);
5749 }
5750 #endif
5751 
5752 #ifdef CONFIG_MEMORY_FAILURE
5753 bool is_free_buddy_page(struct page *page)
5754 {
5755         struct zone *zone = page_zone(page);
5756         unsigned long pfn = page_to_pfn(page);
5757         unsigned long flags;
5758         int order;
5759 
5760         spin_lock_irqsave(&zone->lock, flags);
5761         for (order = 0; order < MAX_ORDER; order++) {
5762                 struct page *page_head = page - (pfn & ((1 << order) - 1));
5763 
5764                 if (PageBuddy(page_head) && page_order(page_head) >= order)
5765                         break;
5766         }
5767         spin_unlock_irqrestore(&zone->lock, flags);
5768 
5769         return order < MAX_ORDER;
5770 }
5771 #endif
5772 
5773 static struct trace_print_flags pageflag_names[] = {
5774         {1UL << PG_locked,              "locked"        },
5775         {1UL << PG_error,               "error"         },
5776         {1UL << PG_referenced,          "referenced"    },
5777         {1UL << PG_uptodate,            "uptodate"      },
5778         {1UL << PG_dirty,               "dirty"         },
5779         {1UL << PG_lru,                 "lru"           },
5780         {1UL << PG_active,              "active"        },
5781         {1UL << PG_slab,                "slab"          },
5782         {1UL << PG_owner_priv_1,        "owner_priv_1"  },
5783         {1UL << PG_arch_1,              "arch_1"        },
5784         {1UL << PG_reserved,            "reserved"      },
5785         {1UL << PG_private,             "private"       },
5786         {1UL << PG_private_2,           "private_2"     },
5787         {1UL << PG_writeback,           "writeback"     },
5788 #ifdef CONFIG_PAGEFLAGS_EXTENDED
5789         {1UL << PG_head,                "head"          },
5790         {1UL << PG_tail,                "tail"          },
5791 #else
5792         {1UL << PG_compound,            "compound"      },
5793 #endif
5794         {1UL << PG_swapcache,           "swapcache"     },
5795         {1UL << PG_mappedtodisk,        "mappedtodisk"  },
5796         {1UL << PG_reclaim,             "reclaim"       },
5797         {1UL << PG_swapbacked,          "swapbacked"    },
5798         {1UL << PG_unevictable,         "unevictable"   },
5799 #ifdef CONFIG_MMU
5800         {1UL << PG_mlocked,             "mlocked"       },
5801 #endif
5802 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
5803         {1UL << PG_uncached,            "uncached"      },
5804 #endif
5805 #ifdef CONFIG_MEMORY_FAILURE
5806         {1UL << PG_hwpoison,            "hwpoison"      },
5807 #endif
5808         {-1UL,                          NULL            },
5809 };
5810 
5811 static void dump_page_flags(unsigned long flags)
5812 {
5813         const char *delim = "";
5814         unsigned long mask;
5815         int i;
5816 
5817         printk(KERN_ALERT "page flags: %#lx(", flags);
5818 
5819         /* remove zone id */
5820         flags &= (1UL << NR_PAGEFLAGS) - 1;
5821 
5822         for (i = 0; pageflag_names[i].name && flags; i++) {
5823 
5824                 mask = pageflag_names[i].mask;
5825                 if ((flags & mask) != mask)
5826                         continue;
5827 
5828                 flags &= ~mask;
5829                 printk("%s%s", delim, pageflag_names[i].name);
5830                 delim = "|";
5831         }
5832 
5833         /* check for left over flags */
5834         if (flags)
5835                 printk("%s%#lx", delim, flags);
5836 
5837         printk(")\n");
5838 }
5839 
5840 void dump_page(struct page *page)
5841 {
5842         printk(KERN_ALERT
5843                "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
5844                 page, atomic_read(&page->_count), page_mapcount(page),
5845                 page->mapping, page->index);
5846         dump_page_flags(page->flags);
5847         mem_cgroup_print_bad_page(page);
5848 }
5849 

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