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TOMOYO Linux Cross Reference
Linux/mm/memory_hotplug.c

Version: ~ [ linux-5.5-rc1 ] ~ [ linux-5.4.2 ] ~ [ linux-5.3.15 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.88 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.158 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.206 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.206 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.78 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /*
  2  *  linux/mm/memory_hotplug.c
  3  *
  4  *  Copyright (C)
  5  */
  6 
  7 #include <linux/stddef.h>
  8 #include <linux/mm.h>
  9 #include <linux/swap.h>
 10 #include <linux/interrupt.h>
 11 #include <linux/pagemap.h>
 12 #include <linux/bootmem.h>
 13 #include <linux/compiler.h>
 14 #include <linux/export.h>
 15 #include <linux/pagevec.h>
 16 #include <linux/writeback.h>
 17 #include <linux/slab.h>
 18 #include <linux/sysctl.h>
 19 #include <linux/cpu.h>
 20 #include <linux/memory.h>
 21 #include <linux/memory_hotplug.h>
 22 #include <linux/highmem.h>
 23 #include <linux/vmalloc.h>
 24 #include <linux/ioport.h>
 25 #include <linux/delay.h>
 26 #include <linux/migrate.h>
 27 #include <linux/page-isolation.h>
 28 #include <linux/pfn.h>
 29 #include <linux/suspend.h>
 30 #include <linux/mm_inline.h>
 31 #include <linux/firmware-map.h>
 32 #include <linux/stop_machine.h>
 33 
 34 #include <asm/tlbflush.h>
 35 
 36 #include "internal.h"
 37 
 38 /*
 39  * online_page_callback contains pointer to current page onlining function.
 40  * Initially it is generic_online_page(). If it is required it could be
 41  * changed by calling set_online_page_callback() for callback registration
 42  * and restore_online_page_callback() for generic callback restore.
 43  */
 44 
 45 static void generic_online_page(struct page *page);
 46 
 47 static online_page_callback_t online_page_callback = generic_online_page;
 48 
 49 DEFINE_MUTEX(mem_hotplug_mutex);
 50 
 51 void lock_memory_hotplug(void)
 52 {
 53         mutex_lock(&mem_hotplug_mutex);
 54 
 55         /* for exclusive hibernation if CONFIG_HIBERNATION=y */
 56         lock_system_sleep();
 57 }
 58 
 59 void unlock_memory_hotplug(void)
 60 {
 61         unlock_system_sleep();
 62         mutex_unlock(&mem_hotplug_mutex);
 63 }
 64 
 65 
 66 /* add this memory to iomem resource */
 67 static struct resource *register_memory_resource(u64 start, u64 size)
 68 {
 69         struct resource *res;
 70         res = kzalloc(sizeof(struct resource), GFP_KERNEL);
 71         BUG_ON(!res);
 72 
 73         res->name = "System RAM";
 74         res->start = start;
 75         res->end = start + size - 1;
 76         res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 77         if (request_resource(&iomem_resource, res) < 0) {
 78                 printk("System RAM resource %pR cannot be added\n", res);
 79                 kfree(res);
 80                 res = NULL;
 81         }
 82         return res;
 83 }
 84 
 85 static void release_memory_resource(struct resource *res)
 86 {
 87         if (!res)
 88                 return;
 89         release_resource(res);
 90         kfree(res);
 91         return;
 92 }
 93 
 94 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 95 void get_page_bootmem(unsigned long info,  struct page *page,
 96                       unsigned long type)
 97 {
 98         page->lru.next = (struct list_head *) type;
 99         SetPagePrivate(page);
100         set_page_private(page, info);
101         atomic_inc(&page->_count);
102 }
103 
104 /* reference to __meminit __free_pages_bootmem is valid
105  * so use __ref to tell modpost not to generate a warning */
106 void __ref put_page_bootmem(struct page *page)
107 {
108         unsigned long type;
109         static DEFINE_MUTEX(ppb_lock);
110 
111         type = (unsigned long) page->lru.next;
112         BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
113                type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
114 
115         if (atomic_dec_return(&page->_count) == 1) {
116                 ClearPagePrivate(page);
117                 set_page_private(page, 0);
118                 INIT_LIST_HEAD(&page->lru);
119 
120                 /*
121                  * Please refer to comment for __free_pages_bootmem()
122                  * for why we serialize here.
123                  */
124                 mutex_lock(&ppb_lock);
125                 __free_pages_bootmem(page, 0);
126                 mutex_unlock(&ppb_lock);
127                 totalram_pages++;
128         }
129 
130 }
131 
132 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
133 #ifndef CONFIG_SPARSEMEM_VMEMMAP
134 static void register_page_bootmem_info_section(unsigned long start_pfn)
135 {
136         unsigned long *usemap, mapsize, section_nr, i;
137         struct mem_section *ms;
138         struct page *page, *memmap;
139 
140         section_nr = pfn_to_section_nr(start_pfn);
141         ms = __nr_to_section(section_nr);
142 
143         /* Get section's memmap address */
144         memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
145 
146         /*
147          * Get page for the memmap's phys address
148          * XXX: need more consideration for sparse_vmemmap...
149          */
150         page = virt_to_page(memmap);
151         mapsize = sizeof(struct page) * PAGES_PER_SECTION;
152         mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
153 
154         /* remember memmap's page */
155         for (i = 0; i < mapsize; i++, page++)
156                 get_page_bootmem(section_nr, page, SECTION_INFO);
157 
158         usemap = __nr_to_section(section_nr)->pageblock_flags;
159         page = virt_to_page(usemap);
160 
161         mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
162 
163         for (i = 0; i < mapsize; i++, page++)
164                 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
165 
166 }
167 #else /* CONFIG_SPARSEMEM_VMEMMAP */
168 static void register_page_bootmem_info_section(unsigned long start_pfn)
169 {
170         unsigned long *usemap, mapsize, section_nr, i;
171         struct mem_section *ms;
172         struct page *page, *memmap;
173 
174         if (!pfn_valid(start_pfn))
175                 return;
176 
177         section_nr = pfn_to_section_nr(start_pfn);
178         ms = __nr_to_section(section_nr);
179 
180         memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
181 
182         register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
183 
184         usemap = __nr_to_section(section_nr)->pageblock_flags;
185         page = virt_to_page(usemap);
186 
187         mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
188 
189         for (i = 0; i < mapsize; i++, page++)
190                 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
191 }
192 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
193 
194 void register_page_bootmem_info_node(struct pglist_data *pgdat)
195 {
196         unsigned long i, pfn, end_pfn, nr_pages;
197         int node = pgdat->node_id;
198         struct page *page;
199         struct zone *zone;
200 
201         nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
202         page = virt_to_page(pgdat);
203 
204         for (i = 0; i < nr_pages; i++, page++)
205                 get_page_bootmem(node, page, NODE_INFO);
206 
207         zone = &pgdat->node_zones[0];
208         for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
209                 if (zone->wait_table) {
210                         nr_pages = zone->wait_table_hash_nr_entries
211                                 * sizeof(wait_queue_head_t);
212                         nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
213                         page = virt_to_page(zone->wait_table);
214 
215                         for (i = 0; i < nr_pages; i++, page++)
216                                 get_page_bootmem(node, page, NODE_INFO);
217                 }
218         }
219 
220         pfn = pgdat->node_start_pfn;
221         end_pfn = pgdat_end_pfn(pgdat);
222 
223         /* register_section info */
224         for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
225                 /*
226                  * Some platforms can assign the same pfn to multiple nodes - on
227                  * node0 as well as nodeN.  To avoid registering a pfn against
228                  * multiple nodes we check that this pfn does not already
229                  * reside in some other node.
230                  */
231                 if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
232                         register_page_bootmem_info_section(pfn);
233         }
234 }
235 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
236 
237 static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
238                            unsigned long end_pfn)
239 {
240         unsigned long old_zone_end_pfn;
241 
242         zone_span_writelock(zone);
243 
244         old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
245         if (!zone->spanned_pages || start_pfn < zone->zone_start_pfn)
246                 zone->zone_start_pfn = start_pfn;
247 
248         zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
249                                 zone->zone_start_pfn;
250 
251         zone_span_writeunlock(zone);
252 }
253 
254 static void resize_zone(struct zone *zone, unsigned long start_pfn,
255                 unsigned long end_pfn)
256 {
257         zone_span_writelock(zone);
258 
259         if (end_pfn - start_pfn) {
260                 zone->zone_start_pfn = start_pfn;
261                 zone->spanned_pages = end_pfn - start_pfn;
262         } else {
263                 /*
264                  * make it consist as free_area_init_core(),
265                  * if spanned_pages = 0, then keep start_pfn = 0
266                  */
267                 zone->zone_start_pfn = 0;
268                 zone->spanned_pages = 0;
269         }
270 
271         zone_span_writeunlock(zone);
272 }
273 
274 static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
275                 unsigned long end_pfn)
276 {
277         enum zone_type zid = zone_idx(zone);
278         int nid = zone->zone_pgdat->node_id;
279         unsigned long pfn;
280 
281         for (pfn = start_pfn; pfn < end_pfn; pfn++)
282                 set_page_links(pfn_to_page(pfn), zid, nid, pfn);
283 }
284 
285 /* Can fail with -ENOMEM from allocating a wait table with vmalloc() or
286  * alloc_bootmem_node_nopanic() */
287 static int __ref ensure_zone_is_initialized(struct zone *zone,
288                         unsigned long start_pfn, unsigned long num_pages)
289 {
290         if (!zone_is_initialized(zone))
291                 return init_currently_empty_zone(zone, start_pfn, num_pages,
292                                                  MEMMAP_HOTPLUG);
293         return 0;
294 }
295 
296 static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
297                 unsigned long start_pfn, unsigned long end_pfn)
298 {
299         int ret;
300         unsigned long flags;
301         unsigned long z1_start_pfn;
302 
303         ret = ensure_zone_is_initialized(z1, start_pfn, end_pfn - start_pfn);
304         if (ret)
305                 return ret;
306 
307         pgdat_resize_lock(z1->zone_pgdat, &flags);
308 
309         /* can't move pfns which are higher than @z2 */
310         if (end_pfn > zone_end_pfn(z2))
311                 goto out_fail;
312         /* the move out part mast at the left most of @z2 */
313         if (start_pfn > z2->zone_start_pfn)
314                 goto out_fail;
315         /* must included/overlap */
316         if (end_pfn <= z2->zone_start_pfn)
317                 goto out_fail;
318 
319         /* use start_pfn for z1's start_pfn if z1 is empty */
320         if (z1->spanned_pages)
321                 z1_start_pfn = z1->zone_start_pfn;
322         else
323                 z1_start_pfn = start_pfn;
324 
325         resize_zone(z1, z1_start_pfn, end_pfn);
326         resize_zone(z2, end_pfn, zone_end_pfn(z2));
327 
328         pgdat_resize_unlock(z1->zone_pgdat, &flags);
329 
330         fix_zone_id(z1, start_pfn, end_pfn);
331 
332         return 0;
333 out_fail:
334         pgdat_resize_unlock(z1->zone_pgdat, &flags);
335         return -1;
336 }
337 
338 static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
339                 unsigned long start_pfn, unsigned long end_pfn)
340 {
341         int ret;
342         unsigned long flags;
343         unsigned long z2_end_pfn;
344 
345         ret = ensure_zone_is_initialized(z2, start_pfn, end_pfn - start_pfn);
346         if (ret)
347                 return ret;
348 
349         pgdat_resize_lock(z1->zone_pgdat, &flags);
350 
351         /* can't move pfns which are lower than @z1 */
352         if (z1->zone_start_pfn > start_pfn)
353                 goto out_fail;
354         /* the move out part mast at the right most of @z1 */
355         if (zone_end_pfn(z1) >  end_pfn)
356                 goto out_fail;
357         /* must included/overlap */
358         if (start_pfn >= zone_end_pfn(z1))
359                 goto out_fail;
360 
361         /* use end_pfn for z2's end_pfn if z2 is empty */
362         if (z2->spanned_pages)
363                 z2_end_pfn = zone_end_pfn(z2);
364         else
365                 z2_end_pfn = end_pfn;
366 
367         resize_zone(z1, z1->zone_start_pfn, start_pfn);
368         resize_zone(z2, start_pfn, z2_end_pfn);
369 
370         pgdat_resize_unlock(z1->zone_pgdat, &flags);
371 
372         fix_zone_id(z2, start_pfn, end_pfn);
373 
374         return 0;
375 out_fail:
376         pgdat_resize_unlock(z1->zone_pgdat, &flags);
377         return -1;
378 }
379 
380 static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
381                             unsigned long end_pfn)
382 {
383         unsigned long old_pgdat_end_pfn =
384                 pgdat->node_start_pfn + pgdat->node_spanned_pages;
385 
386         if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
387                 pgdat->node_start_pfn = start_pfn;
388 
389         pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
390                                         pgdat->node_start_pfn;
391 }
392 
393 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
394 {
395         struct pglist_data *pgdat = zone->zone_pgdat;
396         int nr_pages = PAGES_PER_SECTION;
397         int nid = pgdat->node_id;
398         int zone_type;
399         unsigned long flags;
400         int ret;
401 
402         zone_type = zone - pgdat->node_zones;
403         ret = ensure_zone_is_initialized(zone, phys_start_pfn, nr_pages);
404         if (ret)
405                 return ret;
406 
407         pgdat_resize_lock(zone->zone_pgdat, &flags);
408         grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
409         grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
410                         phys_start_pfn + nr_pages);
411         pgdat_resize_unlock(zone->zone_pgdat, &flags);
412         memmap_init_zone(nr_pages, nid, zone_type,
413                          phys_start_pfn, MEMMAP_HOTPLUG);
414         return 0;
415 }
416 
417 static int __meminit __add_section(int nid, struct zone *zone,
418                                         unsigned long phys_start_pfn)
419 {
420         int nr_pages = PAGES_PER_SECTION;
421         int ret;
422 
423         if (pfn_valid(phys_start_pfn))
424                 return -EEXIST;
425 
426         ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
427 
428         if (ret < 0)
429                 return ret;
430 
431         ret = __add_zone(zone, phys_start_pfn);
432 
433         if (ret < 0)
434                 return ret;
435 
436         return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
437 }
438 
439 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
440 static int find_smallest_section_pfn(int nid, struct zone *zone,
441                                      unsigned long start_pfn,
442                                      unsigned long end_pfn)
443 {
444         struct mem_section *ms;
445 
446         for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
447                 ms = __pfn_to_section(start_pfn);
448 
449                 if (unlikely(!valid_section(ms)))
450                         continue;
451 
452                 if (unlikely(pfn_to_nid(start_pfn) != nid))
453                         continue;
454 
455                 if (zone && zone != page_zone(pfn_to_page(start_pfn)))
456                         continue;
457 
458                 return start_pfn;
459         }
460 
461         return 0;
462 }
463 
464 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
465 static int find_biggest_section_pfn(int nid, struct zone *zone,
466                                     unsigned long start_pfn,
467                                     unsigned long end_pfn)
468 {
469         struct mem_section *ms;
470         unsigned long pfn;
471 
472         /* pfn is the end pfn of a memory section. */
473         pfn = end_pfn - 1;
474         for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
475                 ms = __pfn_to_section(pfn);
476 
477                 if (unlikely(!valid_section(ms)))
478                         continue;
479 
480                 if (unlikely(pfn_to_nid(pfn) != nid))
481                         continue;
482 
483                 if (zone && zone != page_zone(pfn_to_page(pfn)))
484                         continue;
485 
486                 return pfn;
487         }
488 
489         return 0;
490 }
491 
492 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
493                              unsigned long end_pfn)
494 {
495         unsigned long zone_start_pfn =  zone->zone_start_pfn;
496         unsigned long zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
497         unsigned long pfn;
498         struct mem_section *ms;
499         int nid = zone_to_nid(zone);
500 
501         zone_span_writelock(zone);
502         if (zone_start_pfn == start_pfn) {
503                 /*
504                  * If the section is smallest section in the zone, it need
505                  * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
506                  * In this case, we find second smallest valid mem_section
507                  * for shrinking zone.
508                  */
509                 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
510                                                 zone_end_pfn);
511                 if (pfn) {
512                         zone->zone_start_pfn = pfn;
513                         zone->spanned_pages = zone_end_pfn - pfn;
514                 }
515         } else if (zone_end_pfn == end_pfn) {
516                 /*
517                  * If the section is biggest section in the zone, it need
518                  * shrink zone->spanned_pages.
519                  * In this case, we find second biggest valid mem_section for
520                  * shrinking zone.
521                  */
522                 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
523                                                start_pfn);
524                 if (pfn)
525                         zone->spanned_pages = pfn - zone_start_pfn + 1;
526         }
527 
528         /*
529          * The section is not biggest or smallest mem_section in the zone, it
530          * only creates a hole in the zone. So in this case, we need not
531          * change the zone. But perhaps, the zone has only hole data. Thus
532          * it check the zone has only hole or not.
533          */
534         pfn = zone_start_pfn;
535         for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
536                 ms = __pfn_to_section(pfn);
537 
538                 if (unlikely(!valid_section(ms)))
539                         continue;
540 
541                 if (page_zone(pfn_to_page(pfn)) != zone)
542                         continue;
543 
544                  /* If the section is current section, it continues the loop */
545                 if (start_pfn == pfn)
546                         continue;
547 
548                 /* If we find valid section, we have nothing to do */
549                 zone_span_writeunlock(zone);
550                 return;
551         }
552 
553         /* The zone has no valid section */
554         zone->zone_start_pfn = 0;
555         zone->spanned_pages = 0;
556         zone_span_writeunlock(zone);
557 }
558 
559 static void shrink_pgdat_span(struct pglist_data *pgdat,
560                               unsigned long start_pfn, unsigned long end_pfn)
561 {
562         unsigned long pgdat_start_pfn =  pgdat->node_start_pfn;
563         unsigned long pgdat_end_pfn =
564                 pgdat->node_start_pfn + pgdat->node_spanned_pages;
565         unsigned long pfn;
566         struct mem_section *ms;
567         int nid = pgdat->node_id;
568 
569         if (pgdat_start_pfn == start_pfn) {
570                 /*
571                  * If the section is smallest section in the pgdat, it need
572                  * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
573                  * In this case, we find second smallest valid mem_section
574                  * for shrinking zone.
575                  */
576                 pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
577                                                 pgdat_end_pfn);
578                 if (pfn) {
579                         pgdat->node_start_pfn = pfn;
580                         pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
581                 }
582         } else if (pgdat_end_pfn == end_pfn) {
583                 /*
584                  * If the section is biggest section in the pgdat, it need
585                  * shrink pgdat->node_spanned_pages.
586                  * In this case, we find second biggest valid mem_section for
587                  * shrinking zone.
588                  */
589                 pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
590                                                start_pfn);
591                 if (pfn)
592                         pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
593         }
594 
595         /*
596          * If the section is not biggest or smallest mem_section in the pgdat,
597          * it only creates a hole in the pgdat. So in this case, we need not
598          * change the pgdat.
599          * But perhaps, the pgdat has only hole data. Thus it check the pgdat
600          * has only hole or not.
601          */
602         pfn = pgdat_start_pfn;
603         for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
604                 ms = __pfn_to_section(pfn);
605 
606                 if (unlikely(!valid_section(ms)))
607                         continue;
608 
609                 if (pfn_to_nid(pfn) != nid)
610                         continue;
611 
612                  /* If the section is current section, it continues the loop */
613                 if (start_pfn == pfn)
614                         continue;
615 
616                 /* If we find valid section, we have nothing to do */
617                 return;
618         }
619 
620         /* The pgdat has no valid section */
621         pgdat->node_start_pfn = 0;
622         pgdat->node_spanned_pages = 0;
623 }
624 
625 static void __remove_zone(struct zone *zone, unsigned long start_pfn)
626 {
627         struct pglist_data *pgdat = zone->zone_pgdat;
628         int nr_pages = PAGES_PER_SECTION;
629         int zone_type;
630         unsigned long flags;
631 
632         zone_type = zone - pgdat->node_zones;
633 
634         pgdat_resize_lock(zone->zone_pgdat, &flags);
635         shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
636         shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
637         pgdat_resize_unlock(zone->zone_pgdat, &flags);
638 }
639 
640 static int __remove_section(struct zone *zone, struct mem_section *ms)
641 {
642         unsigned long start_pfn;
643         int scn_nr;
644         int ret = -EINVAL;
645 
646         if (!valid_section(ms))
647                 return ret;
648 
649         ret = unregister_memory_section(ms);
650         if (ret)
651                 return ret;
652 
653         scn_nr = __section_nr(ms);
654         start_pfn = section_nr_to_pfn(scn_nr);
655         __remove_zone(zone, start_pfn);
656 
657         sparse_remove_one_section(zone, ms);
658         return 0;
659 }
660 
661 /*
662  * Reasonably generic function for adding memory.  It is
663  * expected that archs that support memory hotplug will
664  * call this function after deciding the zone to which to
665  * add the new pages.
666  */
667 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
668                         unsigned long nr_pages)
669 {
670         unsigned long i;
671         int err = 0;
672         int start_sec, end_sec;
673         /* during initialize mem_map, align hot-added range to section */
674         start_sec = pfn_to_section_nr(phys_start_pfn);
675         end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
676 
677         for (i = start_sec; i <= end_sec; i++) {
678                 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
679 
680                 /*
681                  * EEXIST is finally dealt with by ioresource collision
682                  * check. see add_memory() => register_memory_resource()
683                  * Warning will be printed if there is collision.
684                  */
685                 if (err && (err != -EEXIST))
686                         break;
687                 err = 0;
688         }
689 
690         return err;
691 }
692 EXPORT_SYMBOL_GPL(__add_pages);
693 
694 /**
695  * __remove_pages() - remove sections of pages from a zone
696  * @zone: zone from which pages need to be removed
697  * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
698  * @nr_pages: number of pages to remove (must be multiple of section size)
699  *
700  * Generic helper function to remove section mappings and sysfs entries
701  * for the section of the memory we are removing. Caller needs to make
702  * sure that pages are marked reserved and zones are adjust properly by
703  * calling offline_pages().
704  */
705 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
706                  unsigned long nr_pages)
707 {
708         unsigned long i, ret = 0;
709         int sections_to_remove;
710 
711         /*
712          * We can only remove entire sections
713          */
714         BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
715         BUG_ON(nr_pages % PAGES_PER_SECTION);
716 
717         release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
718 
719         sections_to_remove = nr_pages / PAGES_PER_SECTION;
720         for (i = 0; i < sections_to_remove; i++) {
721                 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
722                 ret = __remove_section(zone, __pfn_to_section(pfn));
723                 if (ret)
724                         break;
725         }
726         return ret;
727 }
728 EXPORT_SYMBOL_GPL(__remove_pages);
729 
730 int set_online_page_callback(online_page_callback_t callback)
731 {
732         int rc = -EINVAL;
733 
734         lock_memory_hotplug();
735 
736         if (online_page_callback == generic_online_page) {
737                 online_page_callback = callback;
738                 rc = 0;
739         }
740 
741         unlock_memory_hotplug();
742 
743         return rc;
744 }
745 EXPORT_SYMBOL_GPL(set_online_page_callback);
746 
747 int restore_online_page_callback(online_page_callback_t callback)
748 {
749         int rc = -EINVAL;
750 
751         lock_memory_hotplug();
752 
753         if (online_page_callback == callback) {
754                 online_page_callback = generic_online_page;
755                 rc = 0;
756         }
757 
758         unlock_memory_hotplug();
759 
760         return rc;
761 }
762 EXPORT_SYMBOL_GPL(restore_online_page_callback);
763 
764 void __online_page_set_limits(struct page *page)
765 {
766         unsigned long pfn = page_to_pfn(page);
767 
768         if (pfn >= num_physpages)
769                 num_physpages = pfn + 1;
770 }
771 EXPORT_SYMBOL_GPL(__online_page_set_limits);
772 
773 void __online_page_increment_counters(struct page *page)
774 {
775         totalram_pages++;
776 
777 #ifdef CONFIG_HIGHMEM
778         if (PageHighMem(page))
779                 totalhigh_pages++;
780 #endif
781 }
782 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
783 
784 void __online_page_free(struct page *page)
785 {
786         ClearPageReserved(page);
787         init_page_count(page);
788         __free_page(page);
789 }
790 EXPORT_SYMBOL_GPL(__online_page_free);
791 
792 static void generic_online_page(struct page *page)
793 {
794         __online_page_set_limits(page);
795         __online_page_increment_counters(page);
796         __online_page_free(page);
797 }
798 
799 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
800                         void *arg)
801 {
802         unsigned long i;
803         unsigned long onlined_pages = *(unsigned long *)arg;
804         struct page *page;
805         if (PageReserved(pfn_to_page(start_pfn)))
806                 for (i = 0; i < nr_pages; i++) {
807                         page = pfn_to_page(start_pfn + i);
808                         (*online_page_callback)(page);
809                         onlined_pages++;
810                 }
811         *(unsigned long *)arg = onlined_pages;
812         return 0;
813 }
814 
815 #ifdef CONFIG_MOVABLE_NODE
816 /*
817  * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
818  * normal memory.
819  */
820 static bool can_online_high_movable(struct zone *zone)
821 {
822         return true;
823 }
824 #else /* CONFIG_MOVABLE_NODE */
825 /* ensure every online node has NORMAL memory */
826 static bool can_online_high_movable(struct zone *zone)
827 {
828         return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
829 }
830 #endif /* CONFIG_MOVABLE_NODE */
831 
832 /* check which state of node_states will be changed when online memory */
833 static void node_states_check_changes_online(unsigned long nr_pages,
834         struct zone *zone, struct memory_notify *arg)
835 {
836         int nid = zone_to_nid(zone);
837         enum zone_type zone_last = ZONE_NORMAL;
838 
839         /*
840          * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
841          * contains nodes which have zones of 0...ZONE_NORMAL,
842          * set zone_last to ZONE_NORMAL.
843          *
844          * If we don't have HIGHMEM nor movable node,
845          * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
846          * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
847          */
848         if (N_MEMORY == N_NORMAL_MEMORY)
849                 zone_last = ZONE_MOVABLE;
850 
851         /*
852          * if the memory to be online is in a zone of 0...zone_last, and
853          * the zones of 0...zone_last don't have memory before online, we will
854          * need to set the node to node_states[N_NORMAL_MEMORY] after
855          * the memory is online.
856          */
857         if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
858                 arg->status_change_nid_normal = nid;
859         else
860                 arg->status_change_nid_normal = -1;
861 
862 #ifdef CONFIG_HIGHMEM
863         /*
864          * If we have movable node, node_states[N_HIGH_MEMORY]
865          * contains nodes which have zones of 0...ZONE_HIGHMEM,
866          * set zone_last to ZONE_HIGHMEM.
867          *
868          * If we don't have movable node, node_states[N_NORMAL_MEMORY]
869          * contains nodes which have zones of 0...ZONE_MOVABLE,
870          * set zone_last to ZONE_MOVABLE.
871          */
872         zone_last = ZONE_HIGHMEM;
873         if (N_MEMORY == N_HIGH_MEMORY)
874                 zone_last = ZONE_MOVABLE;
875 
876         if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
877                 arg->status_change_nid_high = nid;
878         else
879                 arg->status_change_nid_high = -1;
880 #else
881         arg->status_change_nid_high = arg->status_change_nid_normal;
882 #endif
883 
884         /*
885          * if the node don't have memory befor online, we will need to
886          * set the node to node_states[N_MEMORY] after the memory
887          * is online.
888          */
889         if (!node_state(nid, N_MEMORY))
890                 arg->status_change_nid = nid;
891         else
892                 arg->status_change_nid = -1;
893 }
894 
895 static void node_states_set_node(int node, struct memory_notify *arg)
896 {
897         if (arg->status_change_nid_normal >= 0)
898                 node_set_state(node, N_NORMAL_MEMORY);
899 
900         if (arg->status_change_nid_high >= 0)
901                 node_set_state(node, N_HIGH_MEMORY);
902 
903         node_set_state(node, N_MEMORY);
904 }
905 
906 
907 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
908 {
909         unsigned long onlined_pages = 0;
910         struct zone *zone;
911         int need_zonelists_rebuild = 0;
912         int nid;
913         int ret;
914         struct memory_notify arg;
915 
916         lock_memory_hotplug();
917         /*
918          * This doesn't need a lock to do pfn_to_page().
919          * The section can't be removed here because of the
920          * memory_block->state_mutex.
921          */
922         zone = page_zone(pfn_to_page(pfn));
923 
924         if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) &&
925             !can_online_high_movable(zone)) {
926                 unlock_memory_hotplug();
927                 return -1;
928         }
929 
930         if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
931                 if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
932                         unlock_memory_hotplug();
933                         return -1;
934                 }
935         }
936         if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
937                 if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
938                         unlock_memory_hotplug();
939                         return -1;
940                 }
941         }
942 
943         /* Previous code may changed the zone of the pfn range */
944         zone = page_zone(pfn_to_page(pfn));
945 
946         arg.start_pfn = pfn;
947         arg.nr_pages = nr_pages;
948         node_states_check_changes_online(nr_pages, zone, &arg);
949 
950         nid = page_to_nid(pfn_to_page(pfn));
951 
952         ret = memory_notify(MEM_GOING_ONLINE, &arg);
953         ret = notifier_to_errno(ret);
954         if (ret) {
955                 memory_notify(MEM_CANCEL_ONLINE, &arg);
956                 unlock_memory_hotplug();
957                 return ret;
958         }
959         /*
960          * If this zone is not populated, then it is not in zonelist.
961          * This means the page allocator ignores this zone.
962          * So, zonelist must be updated after online.
963          */
964         mutex_lock(&zonelists_mutex);
965         if (!populated_zone(zone)) {
966                 need_zonelists_rebuild = 1;
967                 build_all_zonelists(NULL, zone);
968         }
969 
970         ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
971                 online_pages_range);
972         if (ret) {
973                 if (need_zonelists_rebuild)
974                         zone_pcp_reset(zone);
975                 mutex_unlock(&zonelists_mutex);
976                 printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n",
977                        (unsigned long long) pfn << PAGE_SHIFT,
978                        (((unsigned long long) pfn + nr_pages)
979                             << PAGE_SHIFT) - 1);
980                 memory_notify(MEM_CANCEL_ONLINE, &arg);
981                 unlock_memory_hotplug();
982                 return ret;
983         }
984 
985         zone->managed_pages += onlined_pages;
986         zone->present_pages += onlined_pages;
987         zone->zone_pgdat->node_present_pages += onlined_pages;
988         if (onlined_pages) {
989                 node_states_set_node(zone_to_nid(zone), &arg);
990                 if (need_zonelists_rebuild)
991                         build_all_zonelists(NULL, NULL);
992                 else
993                         zone_pcp_update(zone);
994         }
995 
996         mutex_unlock(&zonelists_mutex);
997 
998         init_per_zone_wmark_min();
999 
1000         if (onlined_pages)
1001                 kswapd_run(zone_to_nid(zone));
1002 
1003         vm_total_pages = nr_free_pagecache_pages();
1004 
1005         writeback_set_ratelimit();
1006 
1007         if (onlined_pages)
1008                 memory_notify(MEM_ONLINE, &arg);
1009         unlock_memory_hotplug();
1010 
1011         return 0;
1012 }
1013 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
1014 
1015 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1016 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
1017 {
1018         struct pglist_data *pgdat;
1019         unsigned long zones_size[MAX_NR_ZONES] = {0};
1020         unsigned long zholes_size[MAX_NR_ZONES] = {0};
1021         unsigned long start_pfn = start >> PAGE_SHIFT;
1022 
1023         pgdat = NODE_DATA(nid);
1024         if (!pgdat) {
1025                 pgdat = arch_alloc_nodedata(nid);
1026                 if (!pgdat)
1027                         return NULL;
1028 
1029                 arch_refresh_nodedata(nid, pgdat);
1030         }
1031 
1032         /* we can use NODE_DATA(nid) from here */
1033 
1034         /* init node's zones as empty zones, we don't have any present pages.*/
1035         free_area_init_node(nid, zones_size, start_pfn, zholes_size);
1036 
1037         /*
1038          * The node we allocated has no zone fallback lists. For avoiding
1039          * to access not-initialized zonelist, build here.
1040          */
1041         mutex_lock(&zonelists_mutex);
1042         build_all_zonelists(pgdat, NULL);
1043         mutex_unlock(&zonelists_mutex);
1044 
1045         return pgdat;
1046 }
1047 
1048 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
1049 {
1050         arch_refresh_nodedata(nid, NULL);
1051         arch_free_nodedata(pgdat);
1052         return;
1053 }
1054 
1055 
1056 /*
1057  * called by cpu_up() to online a node without onlined memory.
1058  */
1059 int mem_online_node(int nid)
1060 {
1061         pg_data_t       *pgdat;
1062         int     ret;
1063 
1064         lock_memory_hotplug();
1065         pgdat = hotadd_new_pgdat(nid, 0);
1066         if (!pgdat) {
1067                 ret = -ENOMEM;
1068                 goto out;
1069         }
1070         node_set_online(nid);
1071         ret = register_one_node(nid);
1072         BUG_ON(ret);
1073 
1074 out:
1075         unlock_memory_hotplug();
1076         return ret;
1077 }
1078 
1079 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1080 int __ref add_memory(int nid, u64 start, u64 size)
1081 {
1082         pg_data_t *pgdat = NULL;
1083         bool new_pgdat;
1084         bool new_node;
1085         struct resource *res;
1086         int ret;
1087 
1088         lock_memory_hotplug();
1089 
1090         res = register_memory_resource(start, size);
1091         ret = -EEXIST;
1092         if (!res)
1093                 goto out;
1094 
1095         {       /* Stupid hack to suppress address-never-null warning */
1096                 void *p = NODE_DATA(nid);
1097                 new_pgdat = !p;
1098         }
1099         new_node = !node_online(nid);
1100         if (new_node) {
1101                 pgdat = hotadd_new_pgdat(nid, start);
1102                 ret = -ENOMEM;
1103                 if (!pgdat)
1104                         goto error;
1105         }
1106 
1107         /* call arch's memory hotadd */
1108         ret = arch_add_memory(nid, start, size);
1109 
1110         if (ret < 0)
1111                 goto error;
1112 
1113         /* we online node here. we can't roll back from here. */
1114         node_set_online(nid);
1115 
1116         if (new_node) {
1117                 ret = register_one_node(nid);
1118                 /*
1119                  * If sysfs file of new node can't create, cpu on the node
1120                  * can't be hot-added. There is no rollback way now.
1121                  * So, check by BUG_ON() to catch it reluctantly..
1122                  */
1123                 BUG_ON(ret);
1124         }
1125 
1126         /* create new memmap entry */
1127         firmware_map_add_hotplug(start, start + size, "System RAM");
1128 
1129         goto out;
1130 
1131 error:
1132         /* rollback pgdat allocation and others */
1133         if (new_pgdat)
1134                 rollback_node_hotadd(nid, pgdat);
1135         release_memory_resource(res);
1136 
1137 out:
1138         unlock_memory_hotplug();
1139         return ret;
1140 }
1141 EXPORT_SYMBOL_GPL(add_memory);
1142 
1143 #ifdef CONFIG_MEMORY_HOTREMOVE
1144 /*
1145  * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1146  * set and the size of the free page is given by page_order(). Using this,
1147  * the function determines if the pageblock contains only free pages.
1148  * Due to buddy contraints, a free page at least the size of a pageblock will
1149  * be located at the start of the pageblock
1150  */
1151 static inline int pageblock_free(struct page *page)
1152 {
1153         return PageBuddy(page) && page_order(page) >= pageblock_order;
1154 }
1155 
1156 /* Return the start of the next active pageblock after a given page */
1157 static struct page *next_active_pageblock(struct page *page)
1158 {
1159         /* Ensure the starting page is pageblock-aligned */
1160         BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
1161 
1162         /* If the entire pageblock is free, move to the end of free page */
1163         if (pageblock_free(page)) {
1164                 int order;
1165                 /* be careful. we don't have locks, page_order can be changed.*/
1166                 order = page_order(page);
1167                 if ((order < MAX_ORDER) && (order >= pageblock_order))
1168                         return page + (1 << order);
1169         }
1170 
1171         return page + pageblock_nr_pages;
1172 }
1173 
1174 /* Checks if this range of memory is likely to be hot-removable. */
1175 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1176 {
1177         struct page *page = pfn_to_page(start_pfn);
1178         struct page *end_page = page + nr_pages;
1179 
1180         /* Check the starting page of each pageblock within the range */
1181         for (; page < end_page; page = next_active_pageblock(page)) {
1182                 if (!is_pageblock_removable_nolock(page))
1183                         return 0;
1184                 cond_resched();
1185         }
1186 
1187         /* All pageblocks in the memory block are likely to be hot-removable */
1188         return 1;
1189 }
1190 
1191 /*
1192  * Confirm all pages in a range [start, end) is belongs to the same zone.
1193  */
1194 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
1195 {
1196         unsigned long pfn;
1197         struct zone *zone = NULL;
1198         struct page *page;
1199         int i;
1200         for (pfn = start_pfn;
1201              pfn < end_pfn;
1202              pfn += MAX_ORDER_NR_PAGES) {
1203                 i = 0;
1204                 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1205                 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
1206                         i++;
1207                 if (i == MAX_ORDER_NR_PAGES)
1208                         continue;
1209                 page = pfn_to_page(pfn + i);
1210                 if (zone && page_zone(page) != zone)
1211                         return 0;
1212                 zone = page_zone(page);
1213         }
1214         return 1;
1215 }
1216 
1217 /*
1218  * Scanning pfn is much easier than scanning lru list.
1219  * Scan pfn from start to end and Find LRU page.
1220  */
1221 static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
1222 {
1223         unsigned long pfn;
1224         struct page *page;
1225         for (pfn = start; pfn < end; pfn++) {
1226                 if (pfn_valid(pfn)) {
1227                         page = pfn_to_page(pfn);
1228                         if (PageLRU(page))
1229                                 return pfn;
1230                 }
1231         }
1232         return 0;
1233 }
1234 
1235 #define NR_OFFLINE_AT_ONCE_PAGES        (256)
1236 static int
1237 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1238 {
1239         unsigned long pfn;
1240         struct page *page;
1241         int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1242         int not_managed = 0;
1243         int ret = 0;
1244         LIST_HEAD(source);
1245 
1246         for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1247                 if (!pfn_valid(pfn))
1248                         continue;
1249                 page = pfn_to_page(pfn);
1250                 if (!get_page_unless_zero(page))
1251                         continue;
1252                 /*
1253                  * We can skip free pages. And we can only deal with pages on
1254                  * LRU.
1255                  */
1256                 ret = isolate_lru_page(page);
1257                 if (!ret) { /* Success */
1258                         put_page(page);
1259                         list_add_tail(&page->lru, &source);
1260                         move_pages--;
1261                         inc_zone_page_state(page, NR_ISOLATED_ANON +
1262                                             page_is_file_cache(page));
1263 
1264                 } else {
1265 #ifdef CONFIG_DEBUG_VM
1266                         printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
1267                                pfn);
1268                         dump_page(page);
1269 #endif
1270                         put_page(page);
1271                         /* Because we don't have big zone->lock. we should
1272                            check this again here. */
1273                         if (page_count(page)) {
1274                                 not_managed++;
1275                                 ret = -EBUSY;
1276                                 break;
1277                         }
1278                 }
1279         }
1280         if (!list_empty(&source)) {
1281                 if (not_managed) {
1282                         putback_lru_pages(&source);
1283                         goto out;
1284                 }
1285 
1286                 /*
1287                  * alloc_migrate_target should be improooooved!!
1288                  * migrate_pages returns # of failed pages.
1289                  */
1290                 ret = migrate_pages(&source, alloc_migrate_target, 0,
1291                                         MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1292                 if (ret)
1293                         putback_lru_pages(&source);
1294         }
1295 out:
1296         return ret;
1297 }
1298 
1299 /*
1300  * remove from free_area[] and mark all as Reserved.
1301  */
1302 static int
1303 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1304                         void *data)
1305 {
1306         __offline_isolated_pages(start, start + nr_pages);
1307         return 0;
1308 }
1309 
1310 static void
1311 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1312 {
1313         walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1314                                 offline_isolated_pages_cb);
1315 }
1316 
1317 /*
1318  * Check all pages in range, recoreded as memory resource, are isolated.
1319  */
1320 static int
1321 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1322                         void *data)
1323 {
1324         int ret;
1325         long offlined = *(long *)data;
1326         ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1327         offlined = nr_pages;
1328         if (!ret)
1329                 *(long *)data += offlined;
1330         return ret;
1331 }
1332 
1333 static long
1334 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1335 {
1336         long offlined = 0;
1337         int ret;
1338 
1339         ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1340                         check_pages_isolated_cb);
1341         if (ret < 0)
1342                 offlined = (long)ret;
1343         return offlined;
1344 }
1345 
1346 #ifdef CONFIG_MOVABLE_NODE
1347 /*
1348  * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have
1349  * normal memory.
1350  */
1351 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1352 {
1353         return true;
1354 }
1355 #else /* CONFIG_MOVABLE_NODE */
1356 /* ensure the node has NORMAL memory if it is still online */
1357 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1358 {
1359         struct pglist_data *pgdat = zone->zone_pgdat;
1360         unsigned long present_pages = 0;
1361         enum zone_type zt;
1362 
1363         for (zt = 0; zt <= ZONE_NORMAL; zt++)
1364                 present_pages += pgdat->node_zones[zt].present_pages;
1365 
1366         if (present_pages > nr_pages)
1367                 return true;
1368 
1369         present_pages = 0;
1370         for (; zt <= ZONE_MOVABLE; zt++)
1371                 present_pages += pgdat->node_zones[zt].present_pages;
1372 
1373         /*
1374          * we can't offline the last normal memory until all
1375          * higher memory is offlined.
1376          */
1377         return present_pages == 0;
1378 }
1379 #endif /* CONFIG_MOVABLE_NODE */
1380 
1381 /* check which state of node_states will be changed when offline memory */
1382 static void node_states_check_changes_offline(unsigned long nr_pages,
1383                 struct zone *zone, struct memory_notify *arg)
1384 {
1385         struct pglist_data *pgdat = zone->zone_pgdat;
1386         unsigned long present_pages = 0;
1387         enum zone_type zt, zone_last = ZONE_NORMAL;
1388 
1389         /*
1390          * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
1391          * contains nodes which have zones of 0...ZONE_NORMAL,
1392          * set zone_last to ZONE_NORMAL.
1393          *
1394          * If we don't have HIGHMEM nor movable node,
1395          * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
1396          * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1397          */
1398         if (N_MEMORY == N_NORMAL_MEMORY)
1399                 zone_last = ZONE_MOVABLE;
1400 
1401         /*
1402          * check whether node_states[N_NORMAL_MEMORY] will be changed.
1403          * If the memory to be offline is in a zone of 0...zone_last,
1404          * and it is the last present memory, 0...zone_last will
1405          * become empty after offline , thus we can determind we will
1406          * need to clear the node from node_states[N_NORMAL_MEMORY].
1407          */
1408         for (zt = 0; zt <= zone_last; zt++)
1409                 present_pages += pgdat->node_zones[zt].present_pages;
1410         if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1411                 arg->status_change_nid_normal = zone_to_nid(zone);
1412         else
1413                 arg->status_change_nid_normal = -1;
1414 
1415 #ifdef CONFIG_HIGHMEM
1416         /*
1417          * If we have movable node, node_states[N_HIGH_MEMORY]
1418          * contains nodes which have zones of 0...ZONE_HIGHMEM,
1419          * set zone_last to ZONE_HIGHMEM.
1420          *
1421          * If we don't have movable node, node_states[N_NORMAL_MEMORY]
1422          * contains nodes which have zones of 0...ZONE_MOVABLE,
1423          * set zone_last to ZONE_MOVABLE.
1424          */
1425         zone_last = ZONE_HIGHMEM;
1426         if (N_MEMORY == N_HIGH_MEMORY)
1427                 zone_last = ZONE_MOVABLE;
1428 
1429         for (; zt <= zone_last; zt++)
1430                 present_pages += pgdat->node_zones[zt].present_pages;
1431         if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1432                 arg->status_change_nid_high = zone_to_nid(zone);
1433         else
1434                 arg->status_change_nid_high = -1;
1435 #else
1436         arg->status_change_nid_high = arg->status_change_nid_normal;
1437 #endif
1438 
1439         /*
1440          * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1441          */
1442         zone_last = ZONE_MOVABLE;
1443 
1444         /*
1445          * check whether node_states[N_HIGH_MEMORY] will be changed
1446          * If we try to offline the last present @nr_pages from the node,
1447          * we can determind we will need to clear the node from
1448          * node_states[N_HIGH_MEMORY].
1449          */
1450         for (; zt <= zone_last; zt++)
1451                 present_pages += pgdat->node_zones[zt].present_pages;
1452         if (nr_pages >= present_pages)
1453                 arg->status_change_nid = zone_to_nid(zone);
1454         else
1455                 arg->status_change_nid = -1;
1456 }
1457 
1458 static void node_states_clear_node(int node, struct memory_notify *arg)
1459 {
1460         if (arg->status_change_nid_normal >= 0)
1461                 node_clear_state(node, N_NORMAL_MEMORY);
1462 
1463         if ((N_MEMORY != N_NORMAL_MEMORY) &&
1464             (arg->status_change_nid_high >= 0))
1465                 node_clear_state(node, N_HIGH_MEMORY);
1466 
1467         if ((N_MEMORY != N_HIGH_MEMORY) &&
1468             (arg->status_change_nid >= 0))
1469                 node_clear_state(node, N_MEMORY);
1470 }
1471 
1472 static int __ref __offline_pages(unsigned long start_pfn,
1473                   unsigned long end_pfn, unsigned long timeout)
1474 {
1475         unsigned long pfn, nr_pages, expire;
1476         long offlined_pages;
1477         int ret, drain, retry_max, node;
1478         struct zone *zone;
1479         struct memory_notify arg;
1480 
1481         BUG_ON(start_pfn >= end_pfn);
1482         /* at least, alignment against pageblock is necessary */
1483         if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1484                 return -EINVAL;
1485         if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1486                 return -EINVAL;
1487         /* This makes hotplug much easier...and readable.
1488            we assume this for now. .*/
1489         if (!test_pages_in_a_zone(start_pfn, end_pfn))
1490                 return -EINVAL;
1491 
1492         lock_memory_hotplug();
1493 
1494         zone = page_zone(pfn_to_page(start_pfn));
1495         node = zone_to_nid(zone);
1496         nr_pages = end_pfn - start_pfn;
1497 
1498         ret = -EINVAL;
1499         if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages))
1500                 goto out;
1501 
1502         /* set above range as isolated */
1503         ret = start_isolate_page_range(start_pfn, end_pfn,
1504                                        MIGRATE_MOVABLE, true);
1505         if (ret)
1506                 goto out;
1507 
1508         arg.start_pfn = start_pfn;
1509         arg.nr_pages = nr_pages;
1510         node_states_check_changes_offline(nr_pages, zone, &arg);
1511 
1512         ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1513         ret = notifier_to_errno(ret);
1514         if (ret)
1515                 goto failed_removal;
1516 
1517         pfn = start_pfn;
1518         expire = jiffies + timeout;
1519         drain = 0;
1520         retry_max = 5;
1521 repeat:
1522         /* start memory hot removal */
1523         ret = -EAGAIN;
1524         if (time_after(jiffies, expire))
1525                 goto failed_removal;
1526         ret = -EINTR;
1527         if (signal_pending(current))
1528                 goto failed_removal;
1529         ret = 0;
1530         if (drain) {
1531                 lru_add_drain_all();
1532                 cond_resched();
1533                 drain_all_pages();
1534         }
1535 
1536         pfn = scan_lru_pages(start_pfn, end_pfn);
1537         if (pfn) { /* We have page on LRU */
1538                 ret = do_migrate_range(pfn, end_pfn);
1539                 if (!ret) {
1540                         drain = 1;
1541                         goto repeat;
1542                 } else {
1543                         if (ret < 0)
1544                                 if (--retry_max == 0)
1545                                         goto failed_removal;
1546                         yield();
1547                         drain = 1;
1548                         goto repeat;
1549                 }
1550         }
1551         /* drain all zone's lru pagevec, this is asynchronous... */
1552         lru_add_drain_all();
1553         yield();
1554         /* drain pcp pages, this is synchronous. */
1555         drain_all_pages();
1556         /* check again */
1557         offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1558         if (offlined_pages < 0) {
1559                 ret = -EBUSY;
1560                 goto failed_removal;
1561         }
1562         printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
1563         /* Ok, all of our target is isolated.
1564            We cannot do rollback at this point. */
1565         offline_isolated_pages(start_pfn, end_pfn);
1566         /* reset pagetype flags and makes migrate type to be MOVABLE */
1567         undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1568         /* removal success */
1569         zone->managed_pages -= offlined_pages;
1570         zone->present_pages -= offlined_pages;
1571         zone->zone_pgdat->node_present_pages -= offlined_pages;
1572         totalram_pages -= offlined_pages;
1573 
1574         init_per_zone_wmark_min();
1575 
1576         if (!populated_zone(zone)) {
1577                 zone_pcp_reset(zone);
1578                 mutex_lock(&zonelists_mutex);
1579                 build_all_zonelists(NULL, NULL);
1580                 mutex_unlock(&zonelists_mutex);
1581         } else
1582                 zone_pcp_update(zone);
1583 
1584         node_states_clear_node(node, &arg);
1585         if (arg.status_change_nid >= 0)
1586                 kswapd_stop(node);
1587 
1588         vm_total_pages = nr_free_pagecache_pages();
1589         writeback_set_ratelimit();
1590 
1591         memory_notify(MEM_OFFLINE, &arg);
1592         unlock_memory_hotplug();
1593         return 0;
1594 
1595 failed_removal:
1596         printk(KERN_INFO "memory offlining [mem %#010llx-%#010llx] failed\n",
1597                (unsigned long long) start_pfn << PAGE_SHIFT,
1598                ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1599         memory_notify(MEM_CANCEL_OFFLINE, &arg);
1600         /* pushback to free area */
1601         undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1602 
1603 out:
1604         unlock_memory_hotplug();
1605         return ret;
1606 }
1607 
1608 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1609 {
1610         return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
1611 }
1612 
1613 /**
1614  * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
1615  * @start_pfn: start pfn of the memory range
1616  * @end_pfn: end pft of the memory range
1617  * @arg: argument passed to func
1618  * @func: callback for each memory section walked
1619  *
1620  * This function walks through all present mem sections in range
1621  * [start_pfn, end_pfn) and call func on each mem section.
1622  *
1623  * Returns the return value of func.
1624  */
1625 static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
1626                 void *arg, int (*func)(struct memory_block *, void *))
1627 {
1628         struct memory_block *mem = NULL;
1629         struct mem_section *section;
1630         unsigned long pfn, section_nr;
1631         int ret;
1632 
1633         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1634                 section_nr = pfn_to_section_nr(pfn);
1635                 if (!present_section_nr(section_nr))
1636                         continue;
1637 
1638                 section = __nr_to_section(section_nr);
1639                 /* same memblock? */
1640                 if (mem)
1641                         if ((section_nr >= mem->start_section_nr) &&
1642                             (section_nr <= mem->end_section_nr))
1643                                 continue;
1644 
1645                 mem = find_memory_block_hinted(section, mem);
1646                 if (!mem)
1647                         continue;
1648 
1649                 ret = func(mem, arg);
1650                 if (ret) {
1651                         kobject_put(&mem->dev.kobj);
1652                         return ret;
1653                 }
1654         }
1655 
1656         if (mem)
1657                 kobject_put(&mem->dev.kobj);
1658 
1659         return 0;
1660 }
1661 
1662 /**
1663  * offline_memory_block_cb - callback function for offlining memory block
1664  * @mem: the memory block to be offlined
1665  * @arg: buffer to hold error msg
1666  *
1667  * Always return 0, and put the error msg in arg if any.
1668  */
1669 static int offline_memory_block_cb(struct memory_block *mem, void *arg)
1670 {
1671         int *ret = arg;
1672         int error = offline_memory_block(mem);
1673 
1674         if (error != 0 && *ret == 0)
1675                 *ret = error;
1676 
1677         return 0;
1678 }
1679 
1680 static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
1681 {
1682         int ret = !is_memblock_offlined(mem);
1683 
1684         if (unlikely(ret))
1685                 pr_warn("removing memory fails, because memory "
1686                         "[%#010llx-%#010llx] is onlined\n",
1687                         PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),
1688                         PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1);
1689 
1690         return ret;
1691 }
1692 
1693 static int check_cpu_on_node(void *data)
1694 {
1695         struct pglist_data *pgdat = data;
1696         int cpu;
1697 
1698         for_each_present_cpu(cpu) {
1699                 if (cpu_to_node(cpu) == pgdat->node_id)
1700                         /*
1701                          * the cpu on this node isn't removed, and we can't
1702                          * offline this node.
1703                          */
1704                         return -EBUSY;
1705         }
1706 
1707         return 0;
1708 }
1709 
1710 static void unmap_cpu_on_node(void *data)
1711 {
1712 #ifdef CONFIG_ACPI_NUMA
1713         struct pglist_data *pgdat = data;
1714         int cpu;
1715 
1716         for_each_possible_cpu(cpu)
1717                 if (cpu_to_node(cpu) == pgdat->node_id)
1718                         numa_clear_node(cpu);
1719 #endif
1720 }
1721 
1722 static int check_and_unmap_cpu_on_node(void *data)
1723 {
1724         int ret = check_cpu_on_node(data);
1725 
1726         if (ret)
1727                 return ret;
1728 
1729         /*
1730          * the node will be offlined when we come here, so we can clear
1731          * the cpu_to_node() now.
1732          */
1733 
1734         unmap_cpu_on_node(data);
1735         return 0;
1736 }
1737 
1738 /* offline the node if all memory sections of this node are removed */
1739 void try_offline_node(int nid)
1740 {
1741         pg_data_t *pgdat = NODE_DATA(nid);
1742         unsigned long start_pfn = pgdat->node_start_pfn;
1743         unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
1744         unsigned long pfn;
1745         struct page *pgdat_page = virt_to_page(pgdat);
1746         int i;
1747 
1748         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1749                 unsigned long section_nr = pfn_to_section_nr(pfn);
1750 
1751                 if (!present_section_nr(section_nr))
1752                         continue;
1753 
1754                 if (pfn_to_nid(pfn) != nid)
1755                         continue;
1756 
1757                 /*
1758                  * some memory sections of this node are not removed, and we
1759                  * can't offline node now.
1760                  */
1761                 return;
1762         }
1763 
1764         if (stop_machine(check_and_unmap_cpu_on_node, pgdat, NULL))
1765                 return;
1766 
1767         /*
1768          * all memory/cpu of this node are removed, we can offline this
1769          * node now.
1770          */
1771         node_set_offline(nid);
1772         unregister_one_node(nid);
1773 
1774         if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page))
1775                 /* node data is allocated from boot memory */
1776                 return;
1777 
1778         /* free waittable in each zone */
1779         for (i = 0; i < MAX_NR_ZONES; i++) {
1780                 struct zone *zone = pgdat->node_zones + i;
1781 
1782                 /*
1783                  * wait_table may be allocated from boot memory,
1784                  * here only free if it's allocated by vmalloc.
1785                  */
1786                 if (is_vmalloc_addr(zone->wait_table))
1787                         vfree(zone->wait_table);
1788         }
1789 
1790         /*
1791          * Since there is no way to guarentee the address of pgdat/zone is not
1792          * on stack of any kernel threads or used by other kernel objects
1793          * without reference counting or other symchronizing method, do not
1794          * reset node_data and free pgdat here. Just reset it to 0 and reuse
1795          * the memory when the node is online again.
1796          */
1797         memset(pgdat, 0, sizeof(*pgdat));
1798 }
1799 EXPORT_SYMBOL(try_offline_node);
1800 
1801 int __ref remove_memory(int nid, u64 start, u64 size)
1802 {
1803         unsigned long start_pfn, end_pfn;
1804         int ret = 0;
1805         int retry = 1;
1806 
1807         start_pfn = PFN_DOWN(start);
1808         end_pfn = PFN_UP(start + size - 1);
1809 
1810         /*
1811          * When CONFIG_MEMCG is on, one memory block may be used by other
1812          * blocks to store page cgroup when onlining pages. But we don't know
1813          * in what order pages are onlined. So we iterate twice to offline
1814          * memory:
1815          * 1st iterate: offline every non primary memory block.
1816          * 2nd iterate: offline primary (i.e. first added) memory block.
1817          */
1818 repeat:
1819         walk_memory_range(start_pfn, end_pfn, &ret,
1820                           offline_memory_block_cb);
1821         if (ret) {
1822                 if (!retry)
1823                         return ret;
1824 
1825                 retry = 0;
1826                 ret = 0;
1827                 goto repeat;
1828         }
1829 
1830         lock_memory_hotplug();
1831 
1832         /*
1833          * we have offlined all memory blocks like this:
1834          *   1. lock memory hotplug
1835          *   2. offline a memory block
1836          *   3. unlock memory hotplug
1837          *
1838          * repeat step1-3 to offline the memory block. All memory blocks
1839          * must be offlined before removing memory. But we don't hold the
1840          * lock in the whole operation. So we should check whether all
1841          * memory blocks are offlined.
1842          */
1843 
1844         ret = walk_memory_range(start_pfn, end_pfn, NULL,
1845                                 is_memblock_offlined_cb);
1846         if (ret) {
1847                 unlock_memory_hotplug();
1848                 return ret;
1849         }
1850 
1851         /* remove memmap entry */
1852         firmware_map_remove(start, start + size, "System RAM");
1853 
1854         arch_remove_memory(start, size);
1855 
1856         try_offline_node(nid);
1857 
1858         unlock_memory_hotplug();
1859 
1860         return 0;
1861 }
1862 #else
1863 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1864 {
1865         return -EINVAL;
1866 }
1867 int remove_memory(int nid, u64 start, u64 size)
1868 {
1869         return -EINVAL;
1870 }
1871 #endif /* CONFIG_MEMORY_HOTREMOVE */
1872 EXPORT_SYMBOL_GPL(remove_memory);
1873 

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