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TOMOYO Linux Cross Reference
Linux/mm/memory_hotplug.c

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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/sched/signal.h>
 10 #include <linux/swap.h>
 11 #include <linux/interrupt.h>
 12 #include <linux/pagemap.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/memremap.h>
 22 #include <linux/memory_hotplug.h>
 23 #include <linux/highmem.h>
 24 #include <linux/vmalloc.h>
 25 #include <linux/ioport.h>
 26 #include <linux/delay.h>
 27 #include <linux/migrate.h>
 28 #include <linux/page-isolation.h>
 29 #include <linux/pfn.h>
 30 #include <linux/suspend.h>
 31 #include <linux/mm_inline.h>
 32 #include <linux/firmware-map.h>
 33 #include <linux/stop_machine.h>
 34 #include <linux/hugetlb.h>
 35 #include <linux/memblock.h>
 36 #include <linux/bootmem.h>
 37 #include <linux/compaction.h>
 38 
 39 #include <asm/tlbflush.h>
 40 
 41 #include "internal.h"
 42 
 43 /*
 44  * online_page_callback contains pointer to current page onlining function.
 45  * Initially it is generic_online_page(). If it is required it could be
 46  * changed by calling set_online_page_callback() for callback registration
 47  * and restore_online_page_callback() for generic callback restore.
 48  */
 49 
 50 static void generic_online_page(struct page *page);
 51 
 52 static online_page_callback_t online_page_callback = generic_online_page;
 53 static DEFINE_MUTEX(online_page_callback_lock);
 54 
 55 DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
 56 
 57 void get_online_mems(void)
 58 {
 59         percpu_down_read(&mem_hotplug_lock);
 60 }
 61 
 62 void put_online_mems(void)
 63 {
 64         percpu_up_read(&mem_hotplug_lock);
 65 }
 66 
 67 bool movable_node_enabled = false;
 68 
 69 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
 70 bool memhp_auto_online;
 71 #else
 72 bool memhp_auto_online = true;
 73 #endif
 74 EXPORT_SYMBOL_GPL(memhp_auto_online);
 75 
 76 static int __init setup_memhp_default_state(char *str)
 77 {
 78         if (!strcmp(str, "online"))
 79                 memhp_auto_online = true;
 80         else if (!strcmp(str, "offline"))
 81                 memhp_auto_online = false;
 82 
 83         return 1;
 84 }
 85 __setup("memhp_default_state=", setup_memhp_default_state);
 86 
 87 void mem_hotplug_begin(void)
 88 {
 89         cpus_read_lock();
 90         percpu_down_write(&mem_hotplug_lock);
 91 }
 92 
 93 void mem_hotplug_done(void)
 94 {
 95         percpu_up_write(&mem_hotplug_lock);
 96         cpus_read_unlock();
 97 }
 98 
 99 /* add this memory to iomem resource */
100 static struct resource *register_memory_resource(u64 start, u64 size)
101 {
102         struct resource *res, *conflict;
103         res = kzalloc(sizeof(struct resource), GFP_KERNEL);
104         if (!res)
105                 return ERR_PTR(-ENOMEM);
106 
107         res->name = "System RAM";
108         res->start = start;
109         res->end = start + size - 1;
110         res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
111         conflict =  request_resource_conflict(&iomem_resource, res);
112         if (conflict) {
113                 if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
114                         pr_debug("Device unaddressable memory block "
115                                  "memory hotplug at %#010llx !\n",
116                                  (unsigned long long)start);
117                 }
118                 pr_debug("System RAM resource %pR cannot be added\n", res);
119                 kfree(res);
120                 return ERR_PTR(-EEXIST);
121         }
122         return res;
123 }
124 
125 static void release_memory_resource(struct resource *res)
126 {
127         if (!res)
128                 return;
129         release_resource(res);
130         kfree(res);
131         return;
132 }
133 
134 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
135 void get_page_bootmem(unsigned long info,  struct page *page,
136                       unsigned long type)
137 {
138         page->freelist = (void *)type;
139         SetPagePrivate(page);
140         set_page_private(page, info);
141         page_ref_inc(page);
142 }
143 
144 void put_page_bootmem(struct page *page)
145 {
146         unsigned long type;
147 
148         type = (unsigned long) page->freelist;
149         BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
150                type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
151 
152         if (page_ref_dec_return(page) == 1) {
153                 page->freelist = NULL;
154                 ClearPagePrivate(page);
155                 set_page_private(page, 0);
156                 INIT_LIST_HEAD(&page->lru);
157                 free_reserved_page(page);
158         }
159 }
160 
161 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
162 #ifndef CONFIG_SPARSEMEM_VMEMMAP
163 static void register_page_bootmem_info_section(unsigned long start_pfn)
164 {
165         unsigned long *usemap, mapsize, section_nr, i;
166         struct mem_section *ms;
167         struct page *page, *memmap;
168 
169         section_nr = pfn_to_section_nr(start_pfn);
170         ms = __nr_to_section(section_nr);
171 
172         /* Get section's memmap address */
173         memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
174 
175         /*
176          * Get page for the memmap's phys address
177          * XXX: need more consideration for sparse_vmemmap...
178          */
179         page = virt_to_page(memmap);
180         mapsize = sizeof(struct page) * PAGES_PER_SECTION;
181         mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
182 
183         /* remember memmap's page */
184         for (i = 0; i < mapsize; i++, page++)
185                 get_page_bootmem(section_nr, page, SECTION_INFO);
186 
187         usemap = ms->pageblock_flags;
188         page = virt_to_page(usemap);
189 
190         mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
191 
192         for (i = 0; i < mapsize; i++, page++)
193                 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
194 
195 }
196 #else /* CONFIG_SPARSEMEM_VMEMMAP */
197 static void register_page_bootmem_info_section(unsigned long start_pfn)
198 {
199         unsigned long *usemap, mapsize, section_nr, i;
200         struct mem_section *ms;
201         struct page *page, *memmap;
202 
203         section_nr = pfn_to_section_nr(start_pfn);
204         ms = __nr_to_section(section_nr);
205 
206         memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
207 
208         register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
209 
210         usemap = ms->pageblock_flags;
211         page = virt_to_page(usemap);
212 
213         mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
214 
215         for (i = 0; i < mapsize; i++, page++)
216                 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
217 }
218 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
219 
220 void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
221 {
222         unsigned long i, pfn, end_pfn, nr_pages;
223         int node = pgdat->node_id;
224         struct page *page;
225 
226         nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
227         page = virt_to_page(pgdat);
228 
229         for (i = 0; i < nr_pages; i++, page++)
230                 get_page_bootmem(node, page, NODE_INFO);
231 
232         pfn = pgdat->node_start_pfn;
233         end_pfn = pgdat_end_pfn(pgdat);
234 
235         /* register section info */
236         for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
237                 /*
238                  * Some platforms can assign the same pfn to multiple nodes - on
239                  * node0 as well as nodeN.  To avoid registering a pfn against
240                  * multiple nodes we check that this pfn does not already
241                  * reside in some other nodes.
242                  */
243                 if (pfn_valid(pfn) && (early_pfn_to_nid(pfn) == node))
244                         register_page_bootmem_info_section(pfn);
245         }
246 }
247 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
248 
249 static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
250                 struct vmem_altmap *altmap, bool want_memblock)
251 {
252         int ret;
253 
254         if (pfn_valid(phys_start_pfn))
255                 return -EEXIST;
256 
257         ret = sparse_add_one_section(NODE_DATA(nid), phys_start_pfn, altmap);
258         if (ret < 0)
259                 return ret;
260 
261         if (!want_memblock)
262                 return 0;
263 
264         return hotplug_memory_register(nid, __pfn_to_section(phys_start_pfn));
265 }
266 
267 /*
268  * Reasonably generic function for adding memory.  It is
269  * expected that archs that support memory hotplug will
270  * call this function after deciding the zone to which to
271  * add the new pages.
272  */
273 int __ref __add_pages(int nid, unsigned long phys_start_pfn,
274                 unsigned long nr_pages, struct vmem_altmap *altmap,
275                 bool want_memblock)
276 {
277         unsigned long i;
278         int err = 0;
279         int start_sec, end_sec;
280 
281         /* during initialize mem_map, align hot-added range to section */
282         start_sec = pfn_to_section_nr(phys_start_pfn);
283         end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
284 
285         if (altmap) {
286                 /*
287                  * Validate altmap is within bounds of the total request
288                  */
289                 if (altmap->base_pfn != phys_start_pfn
290                                 || vmem_altmap_offset(altmap) > nr_pages) {
291                         pr_warn_once("memory add fail, invalid altmap\n");
292                         err = -EINVAL;
293                         goto out;
294                 }
295                 altmap->alloc = 0;
296         }
297 
298         for (i = start_sec; i <= end_sec; i++) {
299                 err = __add_section(nid, section_nr_to_pfn(i), altmap,
300                                 want_memblock);
301 
302                 /*
303                  * EEXIST is finally dealt with by ioresource collision
304                  * check. see add_memory() => register_memory_resource()
305                  * Warning will be printed if there is collision.
306                  */
307                 if (err && (err != -EEXIST))
308                         break;
309                 err = 0;
310                 cond_resched();
311         }
312         vmemmap_populate_print_last();
313 out:
314         return err;
315 }
316 
317 #ifdef CONFIG_MEMORY_HOTREMOVE
318 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
319 static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
320                                      unsigned long start_pfn,
321                                      unsigned long end_pfn)
322 {
323         struct mem_section *ms;
324 
325         for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
326                 ms = __pfn_to_section(start_pfn);
327 
328                 if (unlikely(!valid_section(ms)))
329                         continue;
330 
331                 if (unlikely(pfn_to_nid(start_pfn) != nid))
332                         continue;
333 
334                 if (zone && zone != page_zone(pfn_to_page(start_pfn)))
335                         continue;
336 
337                 return start_pfn;
338         }
339 
340         return 0;
341 }
342 
343 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
344 static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
345                                     unsigned long start_pfn,
346                                     unsigned long end_pfn)
347 {
348         struct mem_section *ms;
349         unsigned long pfn;
350 
351         /* pfn is the end pfn of a memory section. */
352         pfn = end_pfn - 1;
353         for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
354                 ms = __pfn_to_section(pfn);
355 
356                 if (unlikely(!valid_section(ms)))
357                         continue;
358 
359                 if (unlikely(pfn_to_nid(pfn) != nid))
360                         continue;
361 
362                 if (zone && zone != page_zone(pfn_to_page(pfn)))
363                         continue;
364 
365                 return pfn;
366         }
367 
368         return 0;
369 }
370 
371 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
372                              unsigned long end_pfn)
373 {
374         unsigned long zone_start_pfn = zone->zone_start_pfn;
375         unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
376         unsigned long zone_end_pfn = z;
377         unsigned long pfn;
378         struct mem_section *ms;
379         int nid = zone_to_nid(zone);
380 
381         zone_span_writelock(zone);
382         if (zone_start_pfn == start_pfn) {
383                 /*
384                  * If the section is smallest section in the zone, it need
385                  * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
386                  * In this case, we find second smallest valid mem_section
387                  * for shrinking zone.
388                  */
389                 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
390                                                 zone_end_pfn);
391                 if (pfn) {
392                         zone->zone_start_pfn = pfn;
393                         zone->spanned_pages = zone_end_pfn - pfn;
394                 }
395         } else if (zone_end_pfn == end_pfn) {
396                 /*
397                  * If the section is biggest section in the zone, it need
398                  * shrink zone->spanned_pages.
399                  * In this case, we find second biggest valid mem_section for
400                  * shrinking zone.
401                  */
402                 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
403                                                start_pfn);
404                 if (pfn)
405                         zone->spanned_pages = pfn - zone_start_pfn + 1;
406         }
407 
408         /*
409          * The section is not biggest or smallest mem_section in the zone, it
410          * only creates a hole in the zone. So in this case, we need not
411          * change the zone. But perhaps, the zone has only hole data. Thus
412          * it check the zone has only hole or not.
413          */
414         pfn = zone_start_pfn;
415         for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
416                 ms = __pfn_to_section(pfn);
417 
418                 if (unlikely(!valid_section(ms)))
419                         continue;
420 
421                 if (page_zone(pfn_to_page(pfn)) != zone)
422                         continue;
423 
424                  /* If the section is current section, it continues the loop */
425                 if (start_pfn == pfn)
426                         continue;
427 
428                 /* If we find valid section, we have nothing to do */
429                 zone_span_writeunlock(zone);
430                 return;
431         }
432 
433         /* The zone has no valid section */
434         zone->zone_start_pfn = 0;
435         zone->spanned_pages = 0;
436         zone_span_writeunlock(zone);
437 }
438 
439 static void shrink_pgdat_span(struct pglist_data *pgdat,
440                               unsigned long start_pfn, unsigned long end_pfn)
441 {
442         unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
443         unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */
444         unsigned long pgdat_end_pfn = p;
445         unsigned long pfn;
446         struct mem_section *ms;
447         int nid = pgdat->node_id;
448 
449         if (pgdat_start_pfn == start_pfn) {
450                 /*
451                  * If the section is smallest section in the pgdat, it need
452                  * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
453                  * In this case, we find second smallest valid mem_section
454                  * for shrinking zone.
455                  */
456                 pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
457                                                 pgdat_end_pfn);
458                 if (pfn) {
459                         pgdat->node_start_pfn = pfn;
460                         pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
461                 }
462         } else if (pgdat_end_pfn == end_pfn) {
463                 /*
464                  * If the section is biggest section in the pgdat, it need
465                  * shrink pgdat->node_spanned_pages.
466                  * In this case, we find second biggest valid mem_section for
467                  * shrinking zone.
468                  */
469                 pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
470                                                start_pfn);
471                 if (pfn)
472                         pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
473         }
474 
475         /*
476          * If the section is not biggest or smallest mem_section in the pgdat,
477          * it only creates a hole in the pgdat. So in this case, we need not
478          * change the pgdat.
479          * But perhaps, the pgdat has only hole data. Thus it check the pgdat
480          * has only hole or not.
481          */
482         pfn = pgdat_start_pfn;
483         for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
484                 ms = __pfn_to_section(pfn);
485 
486                 if (unlikely(!valid_section(ms)))
487                         continue;
488 
489                 if (pfn_to_nid(pfn) != nid)
490                         continue;
491 
492                  /* If the section is current section, it continues the loop */
493                 if (start_pfn == pfn)
494                         continue;
495 
496                 /* If we find valid section, we have nothing to do */
497                 return;
498         }
499 
500         /* The pgdat has no valid section */
501         pgdat->node_start_pfn = 0;
502         pgdat->node_spanned_pages = 0;
503 }
504 
505 static void __remove_zone(struct zone *zone, unsigned long start_pfn)
506 {
507         struct pglist_data *pgdat = zone->zone_pgdat;
508         int nr_pages = PAGES_PER_SECTION;
509         unsigned long flags;
510 
511         pgdat_resize_lock(zone->zone_pgdat, &flags);
512         shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
513         shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
514         pgdat_resize_unlock(zone->zone_pgdat, &flags);
515 }
516 
517 static int __remove_section(struct zone *zone, struct mem_section *ms,
518                 unsigned long map_offset, struct vmem_altmap *altmap)
519 {
520         unsigned long start_pfn;
521         int scn_nr;
522         int ret = -EINVAL;
523 
524         if (!valid_section(ms))
525                 return ret;
526 
527         ret = unregister_memory_section(ms);
528         if (ret)
529                 return ret;
530 
531         scn_nr = __section_nr(ms);
532         start_pfn = section_nr_to_pfn((unsigned long)scn_nr);
533         __remove_zone(zone, start_pfn);
534 
535         sparse_remove_one_section(zone, ms, map_offset, altmap);
536         return 0;
537 }
538 
539 /**
540  * __remove_pages() - remove sections of pages from a zone
541  * @zone: zone from which pages need to be removed
542  * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
543  * @nr_pages: number of pages to remove (must be multiple of section size)
544  * @altmap: alternative device page map or %NULL if default memmap is used
545  *
546  * Generic helper function to remove section mappings and sysfs entries
547  * for the section of the memory we are removing. Caller needs to make
548  * sure that pages are marked reserved and zones are adjust properly by
549  * calling offline_pages().
550  */
551 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
552                  unsigned long nr_pages, struct vmem_altmap *altmap)
553 {
554         unsigned long i;
555         unsigned long map_offset = 0;
556         int sections_to_remove, ret = 0;
557 
558         /* In the ZONE_DEVICE case device driver owns the memory region */
559         if (is_dev_zone(zone)) {
560                 if (altmap)
561                         map_offset = vmem_altmap_offset(altmap);
562         } else {
563                 resource_size_t start, size;
564 
565                 start = phys_start_pfn << PAGE_SHIFT;
566                 size = nr_pages * PAGE_SIZE;
567 
568                 ret = release_mem_region_adjustable(&iomem_resource, start,
569                                         size);
570                 if (ret) {
571                         resource_size_t endres = start + size - 1;
572 
573                         pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
574                                         &start, &endres, ret);
575                 }
576         }
577 
578         clear_zone_contiguous(zone);
579 
580         /*
581          * We can only remove entire sections
582          */
583         BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
584         BUG_ON(nr_pages % PAGES_PER_SECTION);
585 
586         sections_to_remove = nr_pages / PAGES_PER_SECTION;
587         for (i = 0; i < sections_to_remove; i++) {
588                 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
589 
590                 ret = __remove_section(zone, __pfn_to_section(pfn), map_offset,
591                                 altmap);
592                 map_offset = 0;
593                 if (ret)
594                         break;
595         }
596 
597         set_zone_contiguous(zone);
598 
599         return ret;
600 }
601 #endif /* CONFIG_MEMORY_HOTREMOVE */
602 
603 int set_online_page_callback(online_page_callback_t callback)
604 {
605         int rc = -EINVAL;
606 
607         get_online_mems();
608         mutex_lock(&online_page_callback_lock);
609 
610         if (online_page_callback == generic_online_page) {
611                 online_page_callback = callback;
612                 rc = 0;
613         }
614 
615         mutex_unlock(&online_page_callback_lock);
616         put_online_mems();
617 
618         return rc;
619 }
620 EXPORT_SYMBOL_GPL(set_online_page_callback);
621 
622 int restore_online_page_callback(online_page_callback_t callback)
623 {
624         int rc = -EINVAL;
625 
626         get_online_mems();
627         mutex_lock(&online_page_callback_lock);
628 
629         if (online_page_callback == callback) {
630                 online_page_callback = generic_online_page;
631                 rc = 0;
632         }
633 
634         mutex_unlock(&online_page_callback_lock);
635         put_online_mems();
636 
637         return rc;
638 }
639 EXPORT_SYMBOL_GPL(restore_online_page_callback);
640 
641 void __online_page_set_limits(struct page *page)
642 {
643 }
644 EXPORT_SYMBOL_GPL(__online_page_set_limits);
645 
646 void __online_page_increment_counters(struct page *page)
647 {
648         adjust_managed_page_count(page, 1);
649 }
650 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
651 
652 void __online_page_free(struct page *page)
653 {
654         __free_reserved_page(page);
655 }
656 EXPORT_SYMBOL_GPL(__online_page_free);
657 
658 static void generic_online_page(struct page *page)
659 {
660         __online_page_set_limits(page);
661         __online_page_increment_counters(page);
662         __online_page_free(page);
663 }
664 
665 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
666                         void *arg)
667 {
668         unsigned long i;
669         unsigned long onlined_pages = *(unsigned long *)arg;
670         struct page *page;
671 
672         if (PageReserved(pfn_to_page(start_pfn)))
673                 for (i = 0; i < nr_pages; i++) {
674                         page = pfn_to_page(start_pfn + i);
675                         (*online_page_callback)(page);
676                         onlined_pages++;
677                 }
678 
679         online_mem_sections(start_pfn, start_pfn + nr_pages);
680 
681         *(unsigned long *)arg = onlined_pages;
682         return 0;
683 }
684 
685 /* check which state of node_states will be changed when online memory */
686 static void node_states_check_changes_online(unsigned long nr_pages,
687         struct zone *zone, struct memory_notify *arg)
688 {
689         int nid = zone_to_nid(zone);
690         enum zone_type zone_last = ZONE_NORMAL;
691 
692         /*
693          * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
694          * contains nodes which have zones of 0...ZONE_NORMAL,
695          * set zone_last to ZONE_NORMAL.
696          *
697          * If we don't have HIGHMEM nor movable node,
698          * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
699          * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
700          */
701         if (N_MEMORY == N_NORMAL_MEMORY)
702                 zone_last = ZONE_MOVABLE;
703 
704         /*
705          * if the memory to be online is in a zone of 0...zone_last, and
706          * the zones of 0...zone_last don't have memory before online, we will
707          * need to set the node to node_states[N_NORMAL_MEMORY] after
708          * the memory is online.
709          */
710         if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
711                 arg->status_change_nid_normal = nid;
712         else
713                 arg->status_change_nid_normal = -1;
714 
715 #ifdef CONFIG_HIGHMEM
716         /*
717          * If we have movable node, node_states[N_HIGH_MEMORY]
718          * contains nodes which have zones of 0...ZONE_HIGHMEM,
719          * set zone_last to ZONE_HIGHMEM.
720          *
721          * If we don't have movable node, node_states[N_NORMAL_MEMORY]
722          * contains nodes which have zones of 0...ZONE_MOVABLE,
723          * set zone_last to ZONE_MOVABLE.
724          */
725         zone_last = ZONE_HIGHMEM;
726         if (N_MEMORY == N_HIGH_MEMORY)
727                 zone_last = ZONE_MOVABLE;
728 
729         if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
730                 arg->status_change_nid_high = nid;
731         else
732                 arg->status_change_nid_high = -1;
733 #else
734         arg->status_change_nid_high = arg->status_change_nid_normal;
735 #endif
736 
737         /*
738          * if the node don't have memory befor online, we will need to
739          * set the node to node_states[N_MEMORY] after the memory
740          * is online.
741          */
742         if (!node_state(nid, N_MEMORY))
743                 arg->status_change_nid = nid;
744         else
745                 arg->status_change_nid = -1;
746 }
747 
748 static void node_states_set_node(int node, struct memory_notify *arg)
749 {
750         if (arg->status_change_nid_normal >= 0)
751                 node_set_state(node, N_NORMAL_MEMORY);
752 
753         if (arg->status_change_nid_high >= 0)
754                 node_set_state(node, N_HIGH_MEMORY);
755 
756         node_set_state(node, N_MEMORY);
757 }
758 
759 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
760                 unsigned long nr_pages)
761 {
762         unsigned long old_end_pfn = zone_end_pfn(zone);
763 
764         if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
765                 zone->zone_start_pfn = start_pfn;
766 
767         zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
768 }
769 
770 static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
771                                      unsigned long nr_pages)
772 {
773         unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
774 
775         if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
776                 pgdat->node_start_pfn = start_pfn;
777 
778         pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
779 }
780 
781 void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
782                 unsigned long nr_pages, struct vmem_altmap *altmap)
783 {
784         struct pglist_data *pgdat = zone->zone_pgdat;
785         int nid = pgdat->node_id;
786         unsigned long flags;
787 
788         if (zone_is_empty(zone))
789                 init_currently_empty_zone(zone, start_pfn, nr_pages);
790 
791         clear_zone_contiguous(zone);
792 
793         /* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */
794         pgdat_resize_lock(pgdat, &flags);
795         zone_span_writelock(zone);
796         resize_zone_range(zone, start_pfn, nr_pages);
797         zone_span_writeunlock(zone);
798         resize_pgdat_range(pgdat, start_pfn, nr_pages);
799         pgdat_resize_unlock(pgdat, &flags);
800 
801         /*
802          * TODO now we have a visible range of pages which are not associated
803          * with their zone properly. Not nice but set_pfnblock_flags_mask
804          * expects the zone spans the pfn range. All the pages in the range
805          * are reserved so nobody should be touching them so we should be safe
806          */
807         memmap_init_zone(nr_pages, nid, zone_idx(zone), start_pfn,
808                         MEMMAP_HOTPLUG, altmap);
809 
810         set_zone_contiguous(zone);
811 }
812 
813 /*
814  * Returns a default kernel memory zone for the given pfn range.
815  * If no kernel zone covers this pfn range it will automatically go
816  * to the ZONE_NORMAL.
817  */
818 static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
819                 unsigned long nr_pages)
820 {
821         struct pglist_data *pgdat = NODE_DATA(nid);
822         int zid;
823 
824         for (zid = 0; zid <= ZONE_NORMAL; zid++) {
825                 struct zone *zone = &pgdat->node_zones[zid];
826 
827                 if (zone_intersects(zone, start_pfn, nr_pages))
828                         return zone;
829         }
830 
831         return &pgdat->node_zones[ZONE_NORMAL];
832 }
833 
834 static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
835                 unsigned long nr_pages)
836 {
837         struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
838                         nr_pages);
839         struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
840         bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
841         bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
842 
843         /*
844          * We inherit the existing zone in a simple case where zones do not
845          * overlap in the given range
846          */
847         if (in_kernel ^ in_movable)
848                 return (in_kernel) ? kernel_zone : movable_zone;
849 
850         /*
851          * If the range doesn't belong to any zone or two zones overlap in the
852          * given range then we use movable zone only if movable_node is
853          * enabled because we always online to a kernel zone by default.
854          */
855         return movable_node_enabled ? movable_zone : kernel_zone;
856 }
857 
858 struct zone * zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
859                 unsigned long nr_pages)
860 {
861         if (online_type == MMOP_ONLINE_KERNEL)
862                 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
863 
864         if (online_type == MMOP_ONLINE_MOVABLE)
865                 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
866 
867         return default_zone_for_pfn(nid, start_pfn, nr_pages);
868 }
869 
870 /*
871  * Associates the given pfn range with the given node and the zone appropriate
872  * for the given online type.
873  */
874 static struct zone * __meminit move_pfn_range(int online_type, int nid,
875                 unsigned long start_pfn, unsigned long nr_pages)
876 {
877         struct zone *zone;
878 
879         zone = zone_for_pfn_range(online_type, nid, start_pfn, nr_pages);
880         move_pfn_range_to_zone(zone, start_pfn, nr_pages, NULL);
881         return zone;
882 }
883 
884 /* Must be protected by mem_hotplug_begin() or a device_lock */
885 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
886 {
887         unsigned long flags;
888         unsigned long onlined_pages = 0;
889         struct zone *zone;
890         int need_zonelists_rebuild = 0;
891         int nid;
892         int ret;
893         struct memory_notify arg;
894         struct memory_block *mem;
895 
896         /*
897          * We can't use pfn_to_nid() because nid might be stored in struct page
898          * which is not yet initialized. Instead, we find nid from memory block.
899          */
900         mem = find_memory_block(__pfn_to_section(pfn));
901         nid = mem->nid;
902 
903         /* associate pfn range with the zone */
904         zone = move_pfn_range(online_type, nid, pfn, nr_pages);
905 
906         arg.start_pfn = pfn;
907         arg.nr_pages = nr_pages;
908         node_states_check_changes_online(nr_pages, zone, &arg);
909 
910         ret = memory_notify(MEM_GOING_ONLINE, &arg);
911         ret = notifier_to_errno(ret);
912         if (ret)
913                 goto failed_addition;
914 
915         /*
916          * If this zone is not populated, then it is not in zonelist.
917          * This means the page allocator ignores this zone.
918          * So, zonelist must be updated after online.
919          */
920         if (!populated_zone(zone)) {
921                 need_zonelists_rebuild = 1;
922                 setup_zone_pageset(zone);
923         }
924 
925         ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
926                 online_pages_range);
927         if (ret) {
928                 if (need_zonelists_rebuild)
929                         zone_pcp_reset(zone);
930                 goto failed_addition;
931         }
932 
933         zone->present_pages += onlined_pages;
934 
935         pgdat_resize_lock(zone->zone_pgdat, &flags);
936         zone->zone_pgdat->node_present_pages += onlined_pages;
937         pgdat_resize_unlock(zone->zone_pgdat, &flags);
938 
939         if (onlined_pages) {
940                 node_states_set_node(nid, &arg);
941                 if (need_zonelists_rebuild)
942                         build_all_zonelists(NULL);
943                 else
944                         zone_pcp_update(zone);
945         }
946 
947         init_per_zone_wmark_min();
948 
949         if (onlined_pages) {
950                 kswapd_run(nid);
951                 kcompactd_run(nid);
952         }
953 
954         vm_total_pages = nr_free_pagecache_pages();
955 
956         writeback_set_ratelimit();
957 
958         if (onlined_pages)
959                 memory_notify(MEM_ONLINE, &arg);
960         return 0;
961 
962 failed_addition:
963         pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
964                  (unsigned long long) pfn << PAGE_SHIFT,
965                  (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
966         memory_notify(MEM_CANCEL_ONLINE, &arg);
967         return ret;
968 }
969 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
970 
971 static void reset_node_present_pages(pg_data_t *pgdat)
972 {
973         struct zone *z;
974 
975         for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
976                 z->present_pages = 0;
977 
978         pgdat->node_present_pages = 0;
979 }
980 
981 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
982 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
983 {
984         struct pglist_data *pgdat;
985         unsigned long zones_size[MAX_NR_ZONES] = {0};
986         unsigned long zholes_size[MAX_NR_ZONES] = {0};
987         unsigned long start_pfn = PFN_DOWN(start);
988 
989         pgdat = NODE_DATA(nid);
990         if (!pgdat) {
991                 pgdat = arch_alloc_nodedata(nid);
992                 if (!pgdat)
993                         return NULL;
994 
995                 arch_refresh_nodedata(nid, pgdat);
996         } else {
997                 /*
998                  * Reset the nr_zones, order and classzone_idx before reuse.
999                  * Note that kswapd will init kswapd_classzone_idx properly
1000                  * when it starts in the near future.
1001                  */
1002                 pgdat->nr_zones = 0;
1003                 pgdat->kswapd_order = 0;
1004                 pgdat->kswapd_classzone_idx = 0;
1005         }
1006 
1007         /* we can use NODE_DATA(nid) from here */
1008 
1009         /* init node's zones as empty zones, we don't have any present pages.*/
1010         free_area_init_node(nid, zones_size, start_pfn, zholes_size);
1011         pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);
1012 
1013         /*
1014          * The node we allocated has no zone fallback lists. For avoiding
1015          * to access not-initialized zonelist, build here.
1016          */
1017         build_all_zonelists(pgdat);
1018 
1019         /*
1020          * zone->managed_pages is set to an approximate value in
1021          * free_area_init_core(), which will cause
1022          * /sys/device/system/node/nodeX/meminfo has wrong data.
1023          * So reset it to 0 before any memory is onlined.
1024          */
1025         reset_node_managed_pages(pgdat);
1026 
1027         /*
1028          * When memory is hot-added, all the memory is in offline state. So
1029          * clear all zones' present_pages because they will be updated in
1030          * online_pages() and offline_pages().
1031          */
1032         reset_node_present_pages(pgdat);
1033 
1034         return pgdat;
1035 }
1036 
1037 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
1038 {
1039         arch_refresh_nodedata(nid, NULL);
1040         free_percpu(pgdat->per_cpu_nodestats);
1041         arch_free_nodedata(pgdat);
1042         return;
1043 }
1044 
1045 
1046 /**
1047  * try_online_node - online a node if offlined
1048  * @nid: the node ID
1049  *
1050  * called by cpu_up() to online a node without onlined memory.
1051  */
1052 int try_online_node(int nid)
1053 {
1054         pg_data_t       *pgdat;
1055         int     ret;
1056 
1057         if (node_online(nid))
1058                 return 0;
1059 
1060         mem_hotplug_begin();
1061         pgdat = hotadd_new_pgdat(nid, 0);
1062         if (!pgdat) {
1063                 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1064                 ret = -ENOMEM;
1065                 goto out;
1066         }
1067         node_set_online(nid);
1068         ret = register_one_node(nid);
1069         BUG_ON(ret);
1070 out:
1071         mem_hotplug_done();
1072         return ret;
1073 }
1074 
1075 static int check_hotplug_memory_range(u64 start, u64 size)
1076 {
1077         unsigned long block_sz = memory_block_size_bytes();
1078         u64 block_nr_pages = block_sz >> PAGE_SHIFT;
1079         u64 nr_pages = size >> PAGE_SHIFT;
1080         u64 start_pfn = PFN_DOWN(start);
1081 
1082         /* memory range must be block size aligned */
1083         if (!nr_pages || !IS_ALIGNED(start_pfn, block_nr_pages) ||
1084             !IS_ALIGNED(nr_pages, block_nr_pages)) {
1085                 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1086                        block_sz, start, size);
1087                 return -EINVAL;
1088         }
1089 
1090         return 0;
1091 }
1092 
1093 static int online_memory_block(struct memory_block *mem, void *arg)
1094 {
1095         return device_online(&mem->dev);
1096 }
1097 
1098 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1099 int __ref add_memory_resource(int nid, struct resource *res, bool online)
1100 {
1101         u64 start, size;
1102         pg_data_t *pgdat = NULL;
1103         bool new_pgdat;
1104         bool new_node;
1105         int ret;
1106 
1107         start = res->start;
1108         size = resource_size(res);
1109 
1110         ret = check_hotplug_memory_range(start, size);
1111         if (ret)
1112                 return ret;
1113 
1114         {       /* Stupid hack to suppress address-never-null warning */
1115                 void *p = NODE_DATA(nid);
1116                 new_pgdat = !p;
1117         }
1118 
1119         mem_hotplug_begin();
1120 
1121         /*
1122          * Add new range to memblock so that when hotadd_new_pgdat() is called
1123          * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
1124          * this new range and calculate total pages correctly.  The range will
1125          * be removed at hot-remove time.
1126          */
1127         memblock_add_node(start, size, nid);
1128 
1129         new_node = !node_online(nid);
1130         if (new_node) {
1131                 pgdat = hotadd_new_pgdat(nid, start);
1132                 ret = -ENOMEM;
1133                 if (!pgdat)
1134                         goto error;
1135         }
1136 
1137         /* call arch's memory hotadd */
1138         ret = arch_add_memory(nid, start, size, NULL, true);
1139 
1140         if (ret < 0)
1141                 goto error;
1142 
1143         /* we online node here. we can't roll back from here. */
1144         node_set_online(nid);
1145 
1146         if (new_node) {
1147                 unsigned long start_pfn = start >> PAGE_SHIFT;
1148                 unsigned long nr_pages = size >> PAGE_SHIFT;
1149 
1150                 ret = __register_one_node(nid);
1151                 if (ret)
1152                         goto register_fail;
1153 
1154                 /*
1155                  * link memory sections under this node. This is already
1156                  * done when creatig memory section in register_new_memory
1157                  * but that depends to have the node registered so offline
1158                  * nodes have to go through register_node.
1159                  * TODO clean up this mess.
1160                  */
1161                 ret = link_mem_sections(nid, start_pfn, nr_pages);
1162 register_fail:
1163                 /*
1164                  * If sysfs file of new node can't create, cpu on the node
1165                  * can't be hot-added. There is no rollback way now.
1166                  * So, check by BUG_ON() to catch it reluctantly..
1167                  */
1168                 BUG_ON(ret);
1169         }
1170 
1171         /* create new memmap entry */
1172         firmware_map_add_hotplug(start, start + size, "System RAM");
1173 
1174         /* online pages if requested */
1175         if (online)
1176                 walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
1177                                   NULL, online_memory_block);
1178 
1179         goto out;
1180 
1181 error:
1182         /* rollback pgdat allocation and others */
1183         if (new_pgdat && pgdat)
1184                 rollback_node_hotadd(nid, pgdat);
1185         memblock_remove(start, size);
1186 
1187 out:
1188         mem_hotplug_done();
1189         return ret;
1190 }
1191 EXPORT_SYMBOL_GPL(add_memory_resource);
1192 
1193 int __ref add_memory(int nid, u64 start, u64 size)
1194 {
1195         struct resource *res;
1196         int ret;
1197 
1198         res = register_memory_resource(start, size);
1199         if (IS_ERR(res))
1200                 return PTR_ERR(res);
1201 
1202         ret = add_memory_resource(nid, res, memhp_auto_online);
1203         if (ret < 0)
1204                 release_memory_resource(res);
1205         return ret;
1206 }
1207 EXPORT_SYMBOL_GPL(add_memory);
1208 
1209 #ifdef CONFIG_MEMORY_HOTREMOVE
1210 /*
1211  * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1212  * set and the size of the free page is given by page_order(). Using this,
1213  * the function determines if the pageblock contains only free pages.
1214  * Due to buddy contraints, a free page at least the size of a pageblock will
1215  * be located at the start of the pageblock
1216  */
1217 static inline int pageblock_free(struct page *page)
1218 {
1219         return PageBuddy(page) && page_order(page) >= pageblock_order;
1220 }
1221 
1222 /* Return the start of the next active pageblock after a given page */
1223 static struct page *next_active_pageblock(struct page *page)
1224 {
1225         /* Ensure the starting page is pageblock-aligned */
1226         BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
1227 
1228         /* If the entire pageblock is free, move to the end of free page */
1229         if (pageblock_free(page)) {
1230                 int order;
1231                 /* be careful. we don't have locks, page_order can be changed.*/
1232                 order = page_order(page);
1233                 if ((order < MAX_ORDER) && (order >= pageblock_order))
1234                         return page + (1 << order);
1235         }
1236 
1237         return page + pageblock_nr_pages;
1238 }
1239 
1240 /* Checks if this range of memory is likely to be hot-removable. */
1241 bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1242 {
1243         struct page *page = pfn_to_page(start_pfn);
1244         struct page *end_page = page + nr_pages;
1245 
1246         /* Check the starting page of each pageblock within the range */
1247         for (; page < end_page; page = next_active_pageblock(page)) {
1248                 if (!is_pageblock_removable_nolock(page))
1249                         return false;
1250                 cond_resched();
1251         }
1252 
1253         /* All pageblocks in the memory block are likely to be hot-removable */
1254         return true;
1255 }
1256 
1257 /*
1258  * Confirm all pages in a range [start, end) belong to the same zone.
1259  * When true, return its valid [start, end).
1260  */
1261 int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
1262                          unsigned long *valid_start, unsigned long *valid_end)
1263 {
1264         unsigned long pfn, sec_end_pfn;
1265         unsigned long start, end;
1266         struct zone *zone = NULL;
1267         struct page *page;
1268         int i;
1269         for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1);
1270              pfn < end_pfn;
1271              pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) {
1272                 /* Make sure the memory section is present first */
1273                 if (!present_section_nr(pfn_to_section_nr(pfn)))
1274                         continue;
1275                 for (; pfn < sec_end_pfn && pfn < end_pfn;
1276                      pfn += MAX_ORDER_NR_PAGES) {
1277                         i = 0;
1278                         /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1279                         while ((i < MAX_ORDER_NR_PAGES) &&
1280                                 !pfn_valid_within(pfn + i))
1281                                 i++;
1282                         if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn)
1283                                 continue;
1284                         page = pfn_to_page(pfn + i);
1285                         if (zone && page_zone(page) != zone)
1286                                 return 0;
1287                         if (!zone)
1288                                 start = pfn + i;
1289                         zone = page_zone(page);
1290                         end = pfn + MAX_ORDER_NR_PAGES;
1291                 }
1292         }
1293 
1294         if (zone) {
1295                 *valid_start = start;
1296                 *valid_end = min(end, end_pfn);
1297                 return 1;
1298         } else {
1299                 return 0;
1300         }
1301 }
1302 
1303 /*
1304  * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1305  * non-lru movable pages and hugepages). We scan pfn because it's much
1306  * easier than scanning over linked list. This function returns the pfn
1307  * of the first found movable page if it's found, otherwise 0.
1308  */
1309 static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1310 {
1311         unsigned long pfn;
1312         struct page *page;
1313         for (pfn = start; pfn < end; pfn++) {
1314                 if (pfn_valid(pfn)) {
1315                         page = pfn_to_page(pfn);
1316                         if (PageLRU(page))
1317                                 return pfn;
1318                         if (__PageMovable(page))
1319                                 return pfn;
1320                         if (PageHuge(page)) {
1321                                 if (page_huge_active(page))
1322                                         return pfn;
1323                                 else
1324                                         pfn = round_up(pfn + 1,
1325                                                 1 << compound_order(page)) - 1;
1326                         }
1327                 }
1328         }
1329         return 0;
1330 }
1331 
1332 static struct page *new_node_page(struct page *page, unsigned long private)
1333 {
1334         int nid = page_to_nid(page);
1335         nodemask_t nmask = node_states[N_MEMORY];
1336 
1337         /*
1338          * try to allocate from a different node but reuse this node if there
1339          * are no other online nodes to be used (e.g. we are offlining a part
1340          * of the only existing node)
1341          */
1342         node_clear(nid, nmask);
1343         if (nodes_empty(nmask))
1344                 node_set(nid, nmask);
1345 
1346         return new_page_nodemask(page, nid, &nmask);
1347 }
1348 
1349 #define NR_OFFLINE_AT_ONCE_PAGES        (256)
1350 static int
1351 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1352 {
1353         unsigned long pfn;
1354         struct page *page;
1355         int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1356         int not_managed = 0;
1357         int ret = 0;
1358         LIST_HEAD(source);
1359 
1360         for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1361                 if (!pfn_valid(pfn))
1362                         continue;
1363                 page = pfn_to_page(pfn);
1364 
1365                 if (PageHuge(page)) {
1366                         struct page *head = compound_head(page);
1367                         pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1;
1368                         if (compound_order(head) > PFN_SECTION_SHIFT) {
1369                                 ret = -EBUSY;
1370                                 break;
1371                         }
1372                         if (isolate_huge_page(page, &source))
1373                                 move_pages -= 1 << compound_order(head);
1374                         continue;
1375                 } else if (PageTransHuge(page))
1376                         pfn = page_to_pfn(compound_head(page))
1377                                 + hpage_nr_pages(page) - 1;
1378 
1379                 if (!get_page_unless_zero(page))
1380                         continue;
1381                 /*
1382                  * We can skip free pages. And we can deal with pages on
1383                  * LRU and non-lru movable pages.
1384                  */
1385                 if (PageLRU(page))
1386                         ret = isolate_lru_page(page);
1387                 else
1388                         ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
1389                 if (!ret) { /* Success */
1390                         put_page(page);
1391                         list_add_tail(&page->lru, &source);
1392                         move_pages--;
1393                         if (!__PageMovable(page))
1394                                 inc_node_page_state(page, NR_ISOLATED_ANON +
1395                                                     page_is_file_cache(page));
1396 
1397                 } else {
1398 #ifdef CONFIG_DEBUG_VM
1399                         pr_alert("failed to isolate pfn %lx\n", pfn);
1400                         dump_page(page, "isolation failed");
1401 #endif
1402                         put_page(page);
1403                         /* Because we don't have big zone->lock. we should
1404                            check this again here. */
1405                         if (page_count(page)) {
1406                                 not_managed++;
1407                                 ret = -EBUSY;
1408                                 break;
1409                         }
1410                 }
1411         }
1412         if (!list_empty(&source)) {
1413                 if (not_managed) {
1414                         putback_movable_pages(&source);
1415                         goto out;
1416                 }
1417 
1418                 /* Allocate a new page from the nearest neighbor node */
1419                 ret = migrate_pages(&source, new_node_page, NULL, 0,
1420                                         MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1421                 if (ret)
1422                         putback_movable_pages(&source);
1423         }
1424 out:
1425         return ret;
1426 }
1427 
1428 /*
1429  * remove from free_area[] and mark all as Reserved.
1430  */
1431 static int
1432 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1433                         void *data)
1434 {
1435         __offline_isolated_pages(start, start + nr_pages);
1436         return 0;
1437 }
1438 
1439 static void
1440 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1441 {
1442         walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1443                                 offline_isolated_pages_cb);
1444 }
1445 
1446 /*
1447  * Check all pages in range, recoreded as memory resource, are isolated.
1448  */
1449 static int
1450 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1451                         void *data)
1452 {
1453         int ret;
1454         long offlined = *(long *)data;
1455         ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1456         offlined = nr_pages;
1457         if (!ret)
1458                 *(long *)data += offlined;
1459         return ret;
1460 }
1461 
1462 static long
1463 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1464 {
1465         long offlined = 0;
1466         int ret;
1467 
1468         ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1469                         check_pages_isolated_cb);
1470         if (ret < 0)
1471                 offlined = (long)ret;
1472         return offlined;
1473 }
1474 
1475 static int __init cmdline_parse_movable_node(char *p)
1476 {
1477 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1478         movable_node_enabled = true;
1479 #else
1480         pr_warn("movable_node parameter depends on CONFIG_HAVE_MEMBLOCK_NODE_MAP to work properly\n");
1481 #endif
1482         return 0;
1483 }
1484 early_param("movable_node", cmdline_parse_movable_node);
1485 
1486 /* check which state of node_states will be changed when offline memory */
1487 static void node_states_check_changes_offline(unsigned long nr_pages,
1488                 struct zone *zone, struct memory_notify *arg)
1489 {
1490         struct pglist_data *pgdat = zone->zone_pgdat;
1491         unsigned long present_pages = 0;
1492         enum zone_type zt, zone_last = ZONE_NORMAL;
1493 
1494         /*
1495          * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
1496          * contains nodes which have zones of 0...ZONE_NORMAL,
1497          * set zone_last to ZONE_NORMAL.
1498          *
1499          * If we don't have HIGHMEM nor movable node,
1500          * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
1501          * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1502          */
1503         if (N_MEMORY == N_NORMAL_MEMORY)
1504                 zone_last = ZONE_MOVABLE;
1505 
1506         /*
1507          * check whether node_states[N_NORMAL_MEMORY] will be changed.
1508          * If the memory to be offline is in a zone of 0...zone_last,
1509          * and it is the last present memory, 0...zone_last will
1510          * become empty after offline , thus we can determind we will
1511          * need to clear the node from node_states[N_NORMAL_MEMORY].
1512          */
1513         for (zt = 0; zt <= zone_last; zt++)
1514                 present_pages += pgdat->node_zones[zt].present_pages;
1515         if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1516                 arg->status_change_nid_normal = zone_to_nid(zone);
1517         else
1518                 arg->status_change_nid_normal = -1;
1519 
1520 #ifdef CONFIG_HIGHMEM
1521         /*
1522          * If we have movable node, node_states[N_HIGH_MEMORY]
1523          * contains nodes which have zones of 0...ZONE_HIGHMEM,
1524          * set zone_last to ZONE_HIGHMEM.
1525          *
1526          * If we don't have movable node, node_states[N_NORMAL_MEMORY]
1527          * contains nodes which have zones of 0...ZONE_MOVABLE,
1528          * set zone_last to ZONE_MOVABLE.
1529          */
1530         zone_last = ZONE_HIGHMEM;
1531         if (N_MEMORY == N_HIGH_MEMORY)
1532                 zone_last = ZONE_MOVABLE;
1533 
1534         for (; zt <= zone_last; zt++)
1535                 present_pages += pgdat->node_zones[zt].present_pages;
1536         if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1537                 arg->status_change_nid_high = zone_to_nid(zone);
1538         else
1539                 arg->status_change_nid_high = -1;
1540 #else
1541         arg->status_change_nid_high = arg->status_change_nid_normal;
1542 #endif
1543 
1544         /*
1545          * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1546          */
1547         zone_last = ZONE_MOVABLE;
1548 
1549         /*
1550          * check whether node_states[N_HIGH_MEMORY] will be changed
1551          * If we try to offline the last present @nr_pages from the node,
1552          * we can determind we will need to clear the node from
1553          * node_states[N_HIGH_MEMORY].
1554          */
1555         for (; zt <= zone_last; zt++)
1556                 present_pages += pgdat->node_zones[zt].present_pages;
1557         if (nr_pages >= present_pages)
1558                 arg->status_change_nid = zone_to_nid(zone);
1559         else
1560                 arg->status_change_nid = -1;
1561 }
1562 
1563 static void node_states_clear_node(int node, struct memory_notify *arg)
1564 {
1565         if (arg->status_change_nid_normal >= 0)
1566                 node_clear_state(node, N_NORMAL_MEMORY);
1567 
1568         if ((N_MEMORY != N_NORMAL_MEMORY) &&
1569             (arg->status_change_nid_high >= 0))
1570                 node_clear_state(node, N_HIGH_MEMORY);
1571 
1572         if ((N_MEMORY != N_HIGH_MEMORY) &&
1573             (arg->status_change_nid >= 0))
1574                 node_clear_state(node, N_MEMORY);
1575 }
1576 
1577 static int __ref __offline_pages(unsigned long start_pfn,
1578                   unsigned long end_pfn)
1579 {
1580         unsigned long pfn, nr_pages;
1581         long offlined_pages;
1582         int ret, node;
1583         unsigned long flags;
1584         unsigned long valid_start, valid_end;
1585         struct zone *zone;
1586         struct memory_notify arg;
1587 
1588         /* at least, alignment against pageblock is necessary */
1589         if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1590                 return -EINVAL;
1591         if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1592                 return -EINVAL;
1593         /* This makes hotplug much easier...and readable.
1594            we assume this for now. .*/
1595         if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, &valid_end))
1596                 return -EINVAL;
1597 
1598         zone = page_zone(pfn_to_page(valid_start));
1599         node = zone_to_nid(zone);
1600         nr_pages = end_pfn - start_pfn;
1601 
1602         /* set above range as isolated */
1603         ret = start_isolate_page_range(start_pfn, end_pfn,
1604                                        MIGRATE_MOVABLE, true);
1605         if (ret)
1606                 return ret;
1607 
1608         arg.start_pfn = start_pfn;
1609         arg.nr_pages = nr_pages;
1610         node_states_check_changes_offline(nr_pages, zone, &arg);
1611 
1612         ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1613         ret = notifier_to_errno(ret);
1614         if (ret)
1615                 goto failed_removal;
1616 
1617         pfn = start_pfn;
1618 repeat:
1619         /* start memory hot removal */
1620         ret = -EINTR;
1621         if (signal_pending(current))
1622                 goto failed_removal;
1623 
1624         cond_resched();
1625         lru_add_drain_all();
1626         drain_all_pages(zone);
1627 
1628         pfn = scan_movable_pages(start_pfn, end_pfn);
1629         if (pfn) { /* We have movable pages */
1630                 ret = do_migrate_range(pfn, end_pfn);
1631                 goto repeat;
1632         }
1633 
1634         /*
1635          * dissolve free hugepages in the memory block before doing offlining
1636          * actually in order to make hugetlbfs's object counting consistent.
1637          */
1638         ret = dissolve_free_huge_pages(start_pfn, end_pfn);
1639         if (ret)
1640                 goto failed_removal;
1641         /* check again */
1642         offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1643         if (offlined_pages < 0)
1644                 goto repeat;
1645         pr_info("Offlined Pages %ld\n", offlined_pages);
1646         /* Ok, all of our target is isolated.
1647            We cannot do rollback at this point. */
1648         offline_isolated_pages(start_pfn, end_pfn);
1649         /* reset pagetype flags and makes migrate type to be MOVABLE */
1650         undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1651         /* removal success */
1652         adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
1653         zone->present_pages -= offlined_pages;
1654 
1655         pgdat_resize_lock(zone->zone_pgdat, &flags);
1656         zone->zone_pgdat->node_present_pages -= offlined_pages;
1657         pgdat_resize_unlock(zone->zone_pgdat, &flags);
1658 
1659         init_per_zone_wmark_min();
1660 
1661         if (!populated_zone(zone)) {
1662                 zone_pcp_reset(zone);
1663                 build_all_zonelists(NULL);
1664         } else
1665                 zone_pcp_update(zone);
1666 
1667         node_states_clear_node(node, &arg);
1668         if (arg.status_change_nid >= 0) {
1669                 kswapd_stop(node);
1670                 kcompactd_stop(node);
1671         }
1672 
1673         vm_total_pages = nr_free_pagecache_pages();
1674         writeback_set_ratelimit();
1675 
1676         memory_notify(MEM_OFFLINE, &arg);
1677         return 0;
1678 
1679 failed_removal:
1680         pr_debug("memory offlining [mem %#010llx-%#010llx] failed\n",
1681                  (unsigned long long) start_pfn << PAGE_SHIFT,
1682                  ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1683         memory_notify(MEM_CANCEL_OFFLINE, &arg);
1684         /* pushback to free area */
1685         undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1686         return ret;
1687 }
1688 
1689 /* Must be protected by mem_hotplug_begin() or a device_lock */
1690 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1691 {
1692         return __offline_pages(start_pfn, start_pfn + nr_pages);
1693 }
1694 #endif /* CONFIG_MEMORY_HOTREMOVE */
1695 
1696 /**
1697  * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
1698  * @start_pfn: start pfn of the memory range
1699  * @end_pfn: end pfn of the memory range
1700  * @arg: argument passed to func
1701  * @func: callback for each memory section walked
1702  *
1703  * This function walks through all present mem sections in range
1704  * [start_pfn, end_pfn) and call func on each mem section.
1705  *
1706  * Returns the return value of func.
1707  */
1708 int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
1709                 void *arg, int (*func)(struct memory_block *, void *))
1710 {
1711         struct memory_block *mem = NULL;
1712         struct mem_section *section;
1713         unsigned long pfn, section_nr;
1714         int ret;
1715 
1716         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1717                 section_nr = pfn_to_section_nr(pfn);
1718                 if (!present_section_nr(section_nr))
1719                         continue;
1720 
1721                 section = __nr_to_section(section_nr);
1722                 /* same memblock? */
1723                 if (mem)
1724                         if ((section_nr >= mem->start_section_nr) &&
1725                             (section_nr <= mem->end_section_nr))
1726                                 continue;
1727 
1728                 mem = find_memory_block_hinted(section, mem);
1729                 if (!mem)
1730                         continue;
1731 
1732                 ret = func(mem, arg);
1733                 if (ret) {
1734                         kobject_put(&mem->dev.kobj);
1735                         return ret;
1736                 }
1737         }
1738 
1739         if (mem)
1740                 kobject_put(&mem->dev.kobj);
1741 
1742         return 0;
1743 }
1744 
1745 #ifdef CONFIG_MEMORY_HOTREMOVE
1746 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1747 {
1748         int ret = !is_memblock_offlined(mem);
1749 
1750         if (unlikely(ret)) {
1751                 phys_addr_t beginpa, endpa;
1752 
1753                 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1754                 endpa = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1;
1755                 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1756                         &beginpa, &endpa);
1757         }
1758 
1759         return ret;
1760 }
1761 
1762 static int check_cpu_on_node(pg_data_t *pgdat)
1763 {
1764         int cpu;
1765 
1766         for_each_present_cpu(cpu) {
1767                 if (cpu_to_node(cpu) == pgdat->node_id)
1768                         /*
1769                          * the cpu on this node isn't removed, and we can't
1770                          * offline this node.
1771                          */
1772                         return -EBUSY;
1773         }
1774 
1775         return 0;
1776 }
1777 
1778 static void unmap_cpu_on_node(pg_data_t *pgdat)
1779 {
1780 #ifdef CONFIG_ACPI_NUMA
1781         int cpu;
1782 
1783         for_each_possible_cpu(cpu)
1784                 if (cpu_to_node(cpu) == pgdat->node_id)
1785                         numa_clear_node(cpu);
1786 #endif
1787 }
1788 
1789 static int check_and_unmap_cpu_on_node(pg_data_t *pgdat)
1790 {
1791         int ret;
1792 
1793         ret = check_cpu_on_node(pgdat);
1794         if (ret)
1795                 return ret;
1796 
1797         /*
1798          * the node will be offlined when we come here, so we can clear
1799          * the cpu_to_node() now.
1800          */
1801 
1802         unmap_cpu_on_node(pgdat);
1803         return 0;
1804 }
1805 
1806 /**
1807  * try_offline_node
1808  * @nid: the node ID
1809  *
1810  * Offline a node if all memory sections and cpus of the node are removed.
1811  *
1812  * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1813  * and online/offline operations before this call.
1814  */
1815 void try_offline_node(int nid)
1816 {
1817         pg_data_t *pgdat = NODE_DATA(nid);
1818         unsigned long start_pfn = pgdat->node_start_pfn;
1819         unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
1820         unsigned long pfn;
1821 
1822         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1823                 unsigned long section_nr = pfn_to_section_nr(pfn);
1824 
1825                 if (!present_section_nr(section_nr))
1826                         continue;
1827 
1828                 if (pfn_to_nid(pfn) != nid)
1829                         continue;
1830 
1831                 /*
1832                  * some memory sections of this node are not removed, and we
1833                  * can't offline node now.
1834                  */
1835                 return;
1836         }
1837 
1838         if (check_and_unmap_cpu_on_node(pgdat))
1839                 return;
1840 
1841         /*
1842          * all memory/cpu of this node are removed, we can offline this
1843          * node now.
1844          */
1845         node_set_offline(nid);
1846         unregister_one_node(nid);
1847 }
1848 EXPORT_SYMBOL(try_offline_node);
1849 
1850 /**
1851  * remove_memory
1852  * @nid: the node ID
1853  * @start: physical address of the region to remove
1854  * @size: size of the region to remove
1855  *
1856  * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1857  * and online/offline operations before this call, as required by
1858  * try_offline_node().
1859  */
1860 void __ref remove_memory(int nid, u64 start, u64 size)
1861 {
1862         int ret;
1863 
1864         BUG_ON(check_hotplug_memory_range(start, size));
1865 
1866         mem_hotplug_begin();
1867 
1868         /*
1869          * All memory blocks must be offlined before removing memory.  Check
1870          * whether all memory blocks in question are offline and trigger a BUG()
1871          * if this is not the case.
1872          */
1873         ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
1874                                 check_memblock_offlined_cb);
1875         if (ret)
1876                 BUG();
1877 
1878         /* remove memmap entry */
1879         firmware_map_remove(start, start + size, "System RAM");
1880         memblock_free(start, size);
1881         memblock_remove(start, size);
1882 
1883         arch_remove_memory(start, size, NULL);
1884 
1885         try_offline_node(nid);
1886 
1887         mem_hotplug_done();
1888 }
1889 EXPORT_SYMBOL_GPL(remove_memory);
1890 #endif /* CONFIG_MEMORY_HOTREMOVE */
1891 

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