2 * linux/mm/memory_hotplug.c
7 #include <linux/stddef.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/compaction.h>
38 #include <asm/tlbflush.h>
43 * online_page_callback contains pointer to current page onlining function.
44 * Initially it is generic_online_page(). If it is required it could be
45 * changed by calling set_online_page_callback() for callback registration
46 * and restore_online_page_callback() for generic callback restore.
49 static void generic_online_page(struct page *page);
51 static online_page_callback_t online_page_callback = generic_online_page;
52 static DEFINE_MUTEX(online_page_callback_lock);
54 DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
56 void get_online_mems(void)
58 percpu_down_read(&mem_hotplug_lock);
61 void put_online_mems(void)
63 percpu_up_read(&mem_hotplug_lock);
66 bool movable_node_enabled = false;
68 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
69 bool memhp_auto_online;
71 bool memhp_auto_online = true;
73 EXPORT_SYMBOL_GPL(memhp_auto_online);
75 static int __init setup_memhp_default_state(char *str)
77 if (!strcmp(str, "online"))
78 memhp_auto_online = true;
79 else if (!strcmp(str, "offline"))
80 memhp_auto_online = false;
84 __setup("memhp_default_state=", setup_memhp_default_state);
86 void mem_hotplug_begin(void)
89 percpu_down_write(&mem_hotplug_lock);
92 void mem_hotplug_done(void)
94 percpu_up_write(&mem_hotplug_lock);
98 /* add this memory to iomem resource */
99 static struct resource *register_memory_resource(u64 start, u64 size)
101 struct resource *res, *conflict;
102 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
104 return ERR_PTR(-ENOMEM);
106 res->name = "System RAM";
108 res->end = start + size - 1;
109 res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
110 conflict = request_resource_conflict(&iomem_resource, res);
112 if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
113 pr_debug("Device unaddressable memory block "
114 "memory hotplug at %#010llx !\n",
115 (unsigned long long)start);
117 pr_debug("System RAM resource %pR cannot be added\n", res);
119 return ERR_PTR(-EEXIST);
124 static void release_memory_resource(struct resource *res)
128 release_resource(res);
133 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
134 void get_page_bootmem(unsigned long info, struct page *page,
137 page->freelist = (void *)type;
138 SetPagePrivate(page);
139 set_page_private(page, info);
143 void put_page_bootmem(struct page *page)
147 type = (unsigned long) page->freelist;
148 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
149 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
151 if (page_ref_dec_return(page) == 1) {
152 page->freelist = NULL;
153 ClearPagePrivate(page);
154 set_page_private(page, 0);
155 INIT_LIST_HEAD(&page->lru);
156 free_reserved_page(page);
160 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
161 #ifndef CONFIG_SPARSEMEM_VMEMMAP
162 static void register_page_bootmem_info_section(unsigned long start_pfn)
164 unsigned long *usemap, mapsize, section_nr, i;
165 struct mem_section *ms;
166 struct page *page, *memmap;
168 section_nr = pfn_to_section_nr(start_pfn);
169 ms = __nr_to_section(section_nr);
171 /* Get section's memmap address */
172 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
175 * Get page for the memmap's phys address
176 * XXX: need more consideration for sparse_vmemmap...
178 page = virt_to_page(memmap);
179 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
180 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
182 /* remember memmap's page */
183 for (i = 0; i < mapsize; i++, page++)
184 get_page_bootmem(section_nr, page, SECTION_INFO);
186 usemap = ms->pageblock_flags;
187 page = virt_to_page(usemap);
189 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
191 for (i = 0; i < mapsize; i++, page++)
192 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
195 #else /* CONFIG_SPARSEMEM_VMEMMAP */
196 static void register_page_bootmem_info_section(unsigned long start_pfn)
198 unsigned long *usemap, mapsize, section_nr, i;
199 struct mem_section *ms;
200 struct page *page, *memmap;
202 section_nr = pfn_to_section_nr(start_pfn);
203 ms = __nr_to_section(section_nr);
205 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
207 register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
209 usemap = ms->pageblock_flags;
210 page = virt_to_page(usemap);
212 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
214 for (i = 0; i < mapsize; i++, page++)
215 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
217 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
219 void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
221 unsigned long i, pfn, end_pfn, nr_pages;
222 int node = pgdat->node_id;
225 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
226 page = virt_to_page(pgdat);
228 for (i = 0; i < nr_pages; i++, page++)
229 get_page_bootmem(node, page, NODE_INFO);
231 pfn = pgdat->node_start_pfn;
232 end_pfn = pgdat_end_pfn(pgdat);
234 /* register section info */
235 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
237 * Some platforms can assign the same pfn to multiple nodes - on
238 * node0 as well as nodeN. To avoid registering a pfn against
239 * multiple nodes we check that this pfn does not already
240 * reside in some other nodes.
242 if (pfn_valid(pfn) && (early_pfn_to_nid(pfn) == node))
243 register_page_bootmem_info_section(pfn);
246 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
248 static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
249 struct vmem_altmap *altmap, bool want_memblock)
253 if (pfn_valid(phys_start_pfn))
256 ret = sparse_add_one_section(NODE_DATA(nid), phys_start_pfn, altmap);
263 return hotplug_memory_register(nid, __pfn_to_section(phys_start_pfn));
267 * Reasonably generic function for adding memory. It is
268 * expected that archs that support memory hotplug will
269 * call this function after deciding the zone to which to
272 int __ref __add_pages(int nid, unsigned long phys_start_pfn,
273 unsigned long nr_pages, struct vmem_altmap *altmap,
278 int start_sec, end_sec;
280 /* during initialize mem_map, align hot-added range to section */
281 start_sec = pfn_to_section_nr(phys_start_pfn);
282 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
286 * Validate altmap is within bounds of the total request
288 if (altmap->base_pfn != phys_start_pfn
289 || vmem_altmap_offset(altmap) > nr_pages) {
290 pr_warn_once("memory add fail, invalid altmap\n");
297 for (i = start_sec; i <= end_sec; i++) {
298 err = __add_section(nid, section_nr_to_pfn(i), altmap,
302 * EEXIST is finally dealt with by ioresource collision
303 * check. see add_memory() => register_memory_resource()
304 * Warning will be printed if there is collision.
306 if (err && (err != -EEXIST))
311 vmemmap_populate_print_last();
316 #ifdef CONFIG_MEMORY_HOTREMOVE
317 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
318 static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
319 unsigned long start_pfn,
320 unsigned long end_pfn)
322 struct mem_section *ms;
324 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
325 ms = __pfn_to_section(start_pfn);
327 if (unlikely(!valid_section(ms)))
330 if (unlikely(pfn_to_nid(start_pfn) != nid))
333 if (zone && zone != page_zone(pfn_to_page(start_pfn)))
342 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
343 static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
344 unsigned long start_pfn,
345 unsigned long end_pfn)
347 struct mem_section *ms;
350 /* pfn is the end pfn of a memory section. */
352 for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
353 ms = __pfn_to_section(pfn);
355 if (unlikely(!valid_section(ms)))
358 if (unlikely(pfn_to_nid(pfn) != nid))
361 if (zone && zone != page_zone(pfn_to_page(pfn)))
370 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
371 unsigned long end_pfn)
373 unsigned long zone_start_pfn = zone->zone_start_pfn;
374 unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
375 unsigned long zone_end_pfn = z;
377 struct mem_section *ms;
378 int nid = zone_to_nid(zone);
380 zone_span_writelock(zone);
381 if (zone_start_pfn == start_pfn) {
383 * If the section is smallest section in the zone, it need
384 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
385 * In this case, we find second smallest valid mem_section
386 * for shrinking zone.
388 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
391 zone->zone_start_pfn = pfn;
392 zone->spanned_pages = zone_end_pfn - pfn;
394 } else if (zone_end_pfn == end_pfn) {
396 * If the section is biggest section in the zone, it need
397 * shrink zone->spanned_pages.
398 * In this case, we find second biggest valid mem_section for
401 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
404 zone->spanned_pages = pfn - zone_start_pfn + 1;
408 * The section is not biggest or smallest mem_section in the zone, it
409 * only creates a hole in the zone. So in this case, we need not
410 * change the zone. But perhaps, the zone has only hole data. Thus
411 * it check the zone has only hole or not.
413 pfn = zone_start_pfn;
414 for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
415 ms = __pfn_to_section(pfn);
417 if (unlikely(!valid_section(ms)))
420 if (page_zone(pfn_to_page(pfn)) != zone)
423 /* If the section is current section, it continues the loop */
424 if (start_pfn == pfn)
427 /* If we find valid section, we have nothing to do */
428 zone_span_writeunlock(zone);
432 /* The zone has no valid section */
433 zone->zone_start_pfn = 0;
434 zone->spanned_pages = 0;
435 zone_span_writeunlock(zone);
438 static void shrink_pgdat_span(struct pglist_data *pgdat,
439 unsigned long start_pfn, unsigned long end_pfn)
441 unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
442 unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */
443 unsigned long pgdat_end_pfn = p;
445 struct mem_section *ms;
446 int nid = pgdat->node_id;
448 if (pgdat_start_pfn == start_pfn) {
450 * If the section is smallest section in the pgdat, it need
451 * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
452 * In this case, we find second smallest valid mem_section
453 * for shrinking zone.
455 pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
458 pgdat->node_start_pfn = pfn;
459 pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
461 } else if (pgdat_end_pfn == end_pfn) {
463 * If the section is biggest section in the pgdat, it need
464 * shrink pgdat->node_spanned_pages.
465 * In this case, we find second biggest valid mem_section for
468 pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
471 pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
475 * If the section is not biggest or smallest mem_section in the pgdat,
476 * it only creates a hole in the pgdat. So in this case, we need not
478 * But perhaps, the pgdat has only hole data. Thus it check the pgdat
479 * has only hole or not.
481 pfn = pgdat_start_pfn;
482 for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
483 ms = __pfn_to_section(pfn);
485 if (unlikely(!valid_section(ms)))
488 if (pfn_to_nid(pfn) != nid)
491 /* If the section is current section, it continues the loop */
492 if (start_pfn == pfn)
495 /* If we find valid section, we have nothing to do */
499 /* The pgdat has no valid section */
500 pgdat->node_start_pfn = 0;
501 pgdat->node_spanned_pages = 0;
504 static void __remove_zone(struct zone *zone, unsigned long start_pfn)
506 struct pglist_data *pgdat = zone->zone_pgdat;
507 int nr_pages = PAGES_PER_SECTION;
510 pgdat_resize_lock(zone->zone_pgdat, &flags);
511 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
512 shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
513 pgdat_resize_unlock(zone->zone_pgdat, &flags);
516 static int __remove_section(struct zone *zone, struct mem_section *ms,
517 unsigned long map_offset, struct vmem_altmap *altmap)
519 unsigned long start_pfn;
523 if (!valid_section(ms))
526 ret = unregister_memory_section(ms);
530 scn_nr = __section_nr(ms);
531 start_pfn = section_nr_to_pfn((unsigned long)scn_nr);
532 __remove_zone(zone, start_pfn);
534 sparse_remove_one_section(zone, ms, map_offset, altmap);
539 * __remove_pages() - remove sections of pages from a zone
540 * @zone: zone from which pages need to be removed
541 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
542 * @nr_pages: number of pages to remove (must be multiple of section size)
543 * @altmap: alternative device page map or %NULL if default memmap is used
545 * Generic helper function to remove section mappings and sysfs entries
546 * for the section of the memory we are removing. Caller needs to make
547 * sure that pages are marked reserved and zones are adjust properly by
548 * calling offline_pages().
550 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
551 unsigned long nr_pages, struct vmem_altmap *altmap)
554 unsigned long map_offset = 0;
555 int sections_to_remove, ret = 0;
557 /* In the ZONE_DEVICE case device driver owns the memory region */
558 if (is_dev_zone(zone)) {
560 map_offset = vmem_altmap_offset(altmap);
562 resource_size_t start, size;
564 start = phys_start_pfn << PAGE_SHIFT;
565 size = nr_pages * PAGE_SIZE;
567 ret = release_mem_region_adjustable(&iomem_resource, start,
570 resource_size_t endres = start + size - 1;
572 pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
573 &start, &endres, ret);
577 clear_zone_contiguous(zone);
580 * We can only remove entire sections
582 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
583 BUG_ON(nr_pages % PAGES_PER_SECTION);
585 sections_to_remove = nr_pages / PAGES_PER_SECTION;
586 for (i = 0; i < sections_to_remove; i++) {
587 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
589 ret = __remove_section(zone, __pfn_to_section(pfn), map_offset,
596 set_zone_contiguous(zone);
600 #endif /* CONFIG_MEMORY_HOTREMOVE */
602 int set_online_page_callback(online_page_callback_t callback)
607 mutex_lock(&online_page_callback_lock);
609 if (online_page_callback == generic_online_page) {
610 online_page_callback = callback;
614 mutex_unlock(&online_page_callback_lock);
619 EXPORT_SYMBOL_GPL(set_online_page_callback);
621 int restore_online_page_callback(online_page_callback_t callback)
626 mutex_lock(&online_page_callback_lock);
628 if (online_page_callback == callback) {
629 online_page_callback = generic_online_page;
633 mutex_unlock(&online_page_callback_lock);
638 EXPORT_SYMBOL_GPL(restore_online_page_callback);
640 void __online_page_set_limits(struct page *page)
643 EXPORT_SYMBOL_GPL(__online_page_set_limits);
645 void __online_page_increment_counters(struct page *page)
647 adjust_managed_page_count(page, 1);
649 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
651 void __online_page_free(struct page *page)
653 __free_reserved_page(page);
655 EXPORT_SYMBOL_GPL(__online_page_free);
657 static void generic_online_page(struct page *page)
659 __online_page_set_limits(page);
660 __online_page_increment_counters(page);
661 __online_page_free(page);
664 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
668 unsigned long onlined_pages = *(unsigned long *)arg;
671 if (PageReserved(pfn_to_page(start_pfn)))
672 for (i = 0; i < nr_pages; i++) {
673 page = pfn_to_page(start_pfn + i);
674 (*online_page_callback)(page);
678 online_mem_sections(start_pfn, start_pfn + nr_pages);
680 *(unsigned long *)arg = onlined_pages;
684 /* check which state of node_states will be changed when online memory */
685 static void node_states_check_changes_online(unsigned long nr_pages,
686 struct zone *zone, struct memory_notify *arg)
688 int nid = zone_to_nid(zone);
690 arg->status_change_nid = -1;
691 arg->status_change_nid_normal = -1;
692 arg->status_change_nid_high = -1;
694 if (!node_state(nid, N_MEMORY))
695 arg->status_change_nid = nid;
696 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
697 arg->status_change_nid_normal = nid;
698 #ifdef CONFIG_HIGHMEM
699 if (zone_idx(zone) <= N_HIGH_MEMORY && !node_state(nid, N_HIGH_MEMORY))
700 arg->status_change_nid_high = nid;
704 static void node_states_set_node(int node, struct memory_notify *arg)
706 if (arg->status_change_nid_normal >= 0)
707 node_set_state(node, N_NORMAL_MEMORY);
709 if (arg->status_change_nid_high >= 0)
710 node_set_state(node, N_HIGH_MEMORY);
712 if (arg->status_change_nid >= 0)
713 node_set_state(node, N_MEMORY);
716 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
717 unsigned long nr_pages)
719 unsigned long old_end_pfn = zone_end_pfn(zone);
721 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
722 zone->zone_start_pfn = start_pfn;
724 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
727 static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
728 unsigned long nr_pages)
730 unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
732 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
733 pgdat->node_start_pfn = start_pfn;
735 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
738 void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
739 unsigned long nr_pages, struct vmem_altmap *altmap)
741 struct pglist_data *pgdat = zone->zone_pgdat;
742 int nid = pgdat->node_id;
745 if (zone_is_empty(zone))
746 init_currently_empty_zone(zone, start_pfn, nr_pages);
748 clear_zone_contiguous(zone);
750 /* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */
751 pgdat_resize_lock(pgdat, &flags);
752 zone_span_writelock(zone);
753 resize_zone_range(zone, start_pfn, nr_pages);
754 zone_span_writeunlock(zone);
755 resize_pgdat_range(pgdat, start_pfn, nr_pages);
756 pgdat_resize_unlock(pgdat, &flags);
759 * TODO now we have a visible range of pages which are not associated
760 * with their zone properly. Not nice but set_pfnblock_flags_mask
761 * expects the zone spans the pfn range. All the pages in the range
762 * are reserved so nobody should be touching them so we should be safe
764 memmap_init_zone(nr_pages, nid, zone_idx(zone), start_pfn,
765 MEMMAP_HOTPLUG, altmap);
767 set_zone_contiguous(zone);
771 * Returns a default kernel memory zone for the given pfn range.
772 * If no kernel zone covers this pfn range it will automatically go
773 * to the ZONE_NORMAL.
775 static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
776 unsigned long nr_pages)
778 struct pglist_data *pgdat = NODE_DATA(nid);
781 for (zid = 0; zid <= ZONE_NORMAL; zid++) {
782 struct zone *zone = &pgdat->node_zones[zid];
784 if (zone_intersects(zone, start_pfn, nr_pages))
788 return &pgdat->node_zones[ZONE_NORMAL];
791 static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
792 unsigned long nr_pages)
794 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
796 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
797 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
798 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
801 * We inherit the existing zone in a simple case where zones do not
802 * overlap in the given range
804 if (in_kernel ^ in_movable)
805 return (in_kernel) ? kernel_zone : movable_zone;
808 * If the range doesn't belong to any zone or two zones overlap in the
809 * given range then we use movable zone only if movable_node is
810 * enabled because we always online to a kernel zone by default.
812 return movable_node_enabled ? movable_zone : kernel_zone;
815 struct zone * zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
816 unsigned long nr_pages)
818 if (online_type == MMOP_ONLINE_KERNEL)
819 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
821 if (online_type == MMOP_ONLINE_MOVABLE)
822 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
824 return default_zone_for_pfn(nid, start_pfn, nr_pages);
828 * Associates the given pfn range with the given node and the zone appropriate
829 * for the given online type.
831 static struct zone * __meminit move_pfn_range(int online_type, int nid,
832 unsigned long start_pfn, unsigned long nr_pages)
836 zone = zone_for_pfn_range(online_type, nid, start_pfn, nr_pages);
837 move_pfn_range_to_zone(zone, start_pfn, nr_pages, NULL);
841 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
844 unsigned long onlined_pages = 0;
846 int need_zonelists_rebuild = 0;
849 struct memory_notify arg;
850 struct memory_block *mem;
855 * We can't use pfn_to_nid() because nid might be stored in struct page
856 * which is not yet initialized. Instead, we find nid from memory block.
858 mem = find_memory_block(__pfn_to_section(pfn));
861 /* associate pfn range with the zone */
862 zone = move_pfn_range(online_type, nid, pfn, nr_pages);
865 arg.nr_pages = nr_pages;
866 node_states_check_changes_online(nr_pages, zone, &arg);
868 ret = memory_notify(MEM_GOING_ONLINE, &arg);
869 ret = notifier_to_errno(ret);
871 goto failed_addition;
874 * If this zone is not populated, then it is not in zonelist.
875 * This means the page allocator ignores this zone.
876 * So, zonelist must be updated after online.
878 if (!populated_zone(zone)) {
879 need_zonelists_rebuild = 1;
880 setup_zone_pageset(zone);
883 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
886 if (need_zonelists_rebuild)
887 zone_pcp_reset(zone);
888 goto failed_addition;
891 zone->present_pages += onlined_pages;
893 pgdat_resize_lock(zone->zone_pgdat, &flags);
894 zone->zone_pgdat->node_present_pages += onlined_pages;
895 pgdat_resize_unlock(zone->zone_pgdat, &flags);
898 node_states_set_node(nid, &arg);
899 if (need_zonelists_rebuild)
900 build_all_zonelists(NULL);
902 zone_pcp_update(zone);
905 init_per_zone_wmark_min();
912 vm_total_pages = nr_free_pagecache_pages();
914 writeback_set_ratelimit();
917 memory_notify(MEM_ONLINE, &arg);
922 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
923 (unsigned long long) pfn << PAGE_SHIFT,
924 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
925 memory_notify(MEM_CANCEL_ONLINE, &arg);
929 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
931 static void reset_node_present_pages(pg_data_t *pgdat)
935 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
936 z->present_pages = 0;
938 pgdat->node_present_pages = 0;
941 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
942 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
944 struct pglist_data *pgdat;
945 unsigned long start_pfn = PFN_DOWN(start);
947 pgdat = NODE_DATA(nid);
949 pgdat = arch_alloc_nodedata(nid);
953 arch_refresh_nodedata(nid, pgdat);
956 * Reset the nr_zones, order and classzone_idx before reuse.
957 * Note that kswapd will init kswapd_classzone_idx properly
958 * when it starts in the near future.
961 pgdat->kswapd_order = 0;
962 pgdat->kswapd_classzone_idx = 0;
965 /* we can use NODE_DATA(nid) from here */
967 pgdat->node_id = nid;
968 pgdat->node_start_pfn = start_pfn;
970 /* init node's zones as empty zones, we don't have any present pages.*/
971 free_area_init_core_hotplug(nid);
972 pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);
975 * The node we allocated has no zone fallback lists. For avoiding
976 * to access not-initialized zonelist, build here.
978 build_all_zonelists(pgdat);
981 * When memory is hot-added, all the memory is in offline state. So
982 * clear all zones' present_pages because they will be updated in
983 * online_pages() and offline_pages().
985 reset_node_managed_pages(pgdat);
986 reset_node_present_pages(pgdat);
991 static void rollback_node_hotadd(int nid)
993 pg_data_t *pgdat = NODE_DATA(nid);
995 arch_refresh_nodedata(nid, NULL);
996 free_percpu(pgdat->per_cpu_nodestats);
997 arch_free_nodedata(pgdat);
1003 * try_online_node - online a node if offlined
1005 * @start: start addr of the node
1006 * @set_node_online: Whether we want to online the node
1007 * called by cpu_up() to online a node without onlined memory.
1010 * 1 -> a new node has been allocated
1011 * 0 -> the node is already online
1012 * -ENOMEM -> the node could not be allocated
1014 static int __try_online_node(int nid, u64 start, bool set_node_online)
1019 if (node_online(nid))
1022 pgdat = hotadd_new_pgdat(nid, start);
1024 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1029 if (set_node_online) {
1030 node_set_online(nid);
1031 ret = register_one_node(nid);
1039 * Users of this function always want to online/register the node
1041 int try_online_node(int nid)
1045 mem_hotplug_begin();
1046 ret = __try_online_node(nid, 0, true);
1051 static int check_hotplug_memory_range(u64 start, u64 size)
1053 unsigned long block_sz = memory_block_size_bytes();
1054 u64 block_nr_pages = block_sz >> PAGE_SHIFT;
1055 u64 nr_pages = size >> PAGE_SHIFT;
1056 u64 start_pfn = PFN_DOWN(start);
1058 /* memory range must be block size aligned */
1059 if (!nr_pages || !IS_ALIGNED(start_pfn, block_nr_pages) ||
1060 !IS_ALIGNED(nr_pages, block_nr_pages)) {
1061 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1062 block_sz, start, size);
1069 static int online_memory_block(struct memory_block *mem, void *arg)
1071 return device_online(&mem->dev);
1075 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1076 * and online/offline operations (triggered e.g. by sysfs).
1078 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1080 int __ref add_memory_resource(int nid, struct resource *res, bool online)
1083 bool new_node = false;
1087 size = resource_size(res);
1089 ret = check_hotplug_memory_range(start, size);
1093 mem_hotplug_begin();
1096 * Add new range to memblock so that when hotadd_new_pgdat() is called
1097 * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
1098 * this new range and calculate total pages correctly. The range will
1099 * be removed at hot-remove time.
1101 memblock_add_node(start, size, nid);
1103 ret = __try_online_node(nid, start, false);
1108 /* call arch's memory hotadd */
1109 ret = arch_add_memory(nid, start, size, NULL, true);
1114 /* If sysfs file of new node can't be created, cpu on the node
1115 * can't be hot-added. There is no rollback way now.
1116 * So, check by BUG_ON() to catch it reluctantly..
1117 * We online node here. We can't roll back from here.
1119 node_set_online(nid);
1120 ret = __register_one_node(nid);
1124 /* link memory sections under this node.*/
1125 ret = link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1));
1128 /* create new memmap entry */
1129 firmware_map_add_hotplug(start, start + size, "System RAM");
1131 /* device_online() will take the lock when calling online_pages() */
1134 /* online pages if requested */
1136 walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
1137 NULL, online_memory_block);
1141 /* rollback pgdat allocation and others */
1143 rollback_node_hotadd(nid);
1144 memblock_remove(start, size);
1149 /* requires device_hotplug_lock, see add_memory_resource() */
1150 int __ref __add_memory(int nid, u64 start, u64 size)
1152 struct resource *res;
1155 res = register_memory_resource(start, size);
1157 return PTR_ERR(res);
1159 ret = add_memory_resource(nid, res, memhp_auto_online);
1161 release_memory_resource(res);
1165 int add_memory(int nid, u64 start, u64 size)
1169 lock_device_hotplug();
1170 rc = __add_memory(nid, start, size);
1171 unlock_device_hotplug();
1175 EXPORT_SYMBOL_GPL(add_memory);
1177 #ifdef CONFIG_MEMORY_HOTREMOVE
1179 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1180 * set and the size of the free page is given by page_order(). Using this,
1181 * the function determines if the pageblock contains only free pages.
1182 * Due to buddy contraints, a free page at least the size of a pageblock will
1183 * be located at the start of the pageblock
1185 static inline int pageblock_free(struct page *page)
1187 return PageBuddy(page) && page_order(page) >= pageblock_order;
1190 /* Return the start of the next active pageblock after a given page */
1191 static struct page *next_active_pageblock(struct page *page)
1193 /* Ensure the starting page is pageblock-aligned */
1194 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
1196 /* If the entire pageblock is free, move to the end of free page */
1197 if (pageblock_free(page)) {
1199 /* be careful. we don't have locks, page_order can be changed.*/
1200 order = page_order(page);
1201 if ((order < MAX_ORDER) && (order >= pageblock_order))
1202 return page + (1 << order);
1205 return page + pageblock_nr_pages;
1208 static bool is_pageblock_removable_nolock(struct page *page)
1214 * We have to be careful here because we are iterating over memory
1215 * sections which are not zone aware so we might end up outside of
1216 * the zone but still within the section.
1217 * We have to take care about the node as well. If the node is offline
1218 * its NODE_DATA will be NULL - see page_zone.
1220 if (!node_online(page_to_nid(page)))
1223 zone = page_zone(page);
1224 pfn = page_to_pfn(page);
1225 if (!zone_spans_pfn(zone, pfn))
1228 return !has_unmovable_pages(zone, page, 0, MIGRATE_MOVABLE, true);
1231 /* Checks if this range of memory is likely to be hot-removable. */
1232 bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1234 struct page *page = pfn_to_page(start_pfn);
1235 struct page *end_page = page + nr_pages;
1237 /* Check the starting page of each pageblock within the range */
1238 for (; page < end_page; page = next_active_pageblock(page)) {
1239 if (!is_pageblock_removable_nolock(page))
1244 /* All pageblocks in the memory block are likely to be hot-removable */
1249 * Confirm all pages in a range [start, end) belong to the same zone.
1250 * When true, return its valid [start, end).
1252 int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
1253 unsigned long *valid_start, unsigned long *valid_end)
1255 unsigned long pfn, sec_end_pfn;
1256 unsigned long start, end;
1257 struct zone *zone = NULL;
1260 for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1);
1262 pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) {
1263 /* Make sure the memory section is present first */
1264 if (!present_section_nr(pfn_to_section_nr(pfn)))
1266 for (; pfn < sec_end_pfn && pfn < end_pfn;
1267 pfn += MAX_ORDER_NR_PAGES) {
1269 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1270 while ((i < MAX_ORDER_NR_PAGES) &&
1271 !pfn_valid_within(pfn + i))
1273 if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn)
1275 page = pfn_to_page(pfn + i);
1276 if (zone && page_zone(page) != zone)
1280 zone = page_zone(page);
1281 end = pfn + MAX_ORDER_NR_PAGES;
1286 *valid_start = start;
1287 *valid_end = min(end, end_pfn);
1295 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1296 * non-lru movable pages and hugepages). We scan pfn because it's much
1297 * easier than scanning over linked list. This function returns the pfn
1298 * of the first found movable page if it's found, otherwise 0.
1300 static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1304 for (pfn = start; pfn < end; pfn++) {
1305 if (pfn_valid(pfn)) {
1306 page = pfn_to_page(pfn);
1309 if (__PageMovable(page))
1311 if (PageHuge(page)) {
1312 if (hugepage_migration_supported(page_hstate(page)) &&
1313 page_huge_active(page))
1316 pfn = round_up(pfn + 1,
1317 1 << compound_order(page)) - 1;
1324 static struct page *new_node_page(struct page *page, unsigned long private)
1326 int nid = page_to_nid(page);
1327 nodemask_t nmask = node_states[N_MEMORY];
1330 * try to allocate from a different node but reuse this node if there
1331 * are no other online nodes to be used (e.g. we are offlining a part
1332 * of the only existing node)
1334 node_clear(nid, nmask);
1335 if (nodes_empty(nmask))
1336 node_set(nid, nmask);
1338 return new_page_nodemask(page, nid, &nmask);
1341 #define NR_OFFLINE_AT_ONCE_PAGES (256)
1343 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1347 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1348 int not_managed = 0;
1352 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1353 if (!pfn_valid(pfn))
1355 page = pfn_to_page(pfn);
1357 if (PageHuge(page)) {
1358 struct page *head = compound_head(page);
1359 pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1;
1360 if (compound_order(head) > PFN_SECTION_SHIFT) {
1364 if (isolate_huge_page(page, &source))
1365 move_pages -= 1 << compound_order(head);
1367 } else if (PageTransHuge(page))
1368 pfn = page_to_pfn(compound_head(page))
1369 + hpage_nr_pages(page) - 1;
1371 if (!get_page_unless_zero(page))
1374 * We can skip free pages. And we can deal with pages on
1375 * LRU and non-lru movable pages.
1378 ret = isolate_lru_page(page);
1380 ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
1381 if (!ret) { /* Success */
1383 list_add_tail(&page->lru, &source);
1385 if (!__PageMovable(page))
1386 inc_node_page_state(page, NR_ISOLATED_ANON +
1387 page_is_file_cache(page));
1390 #ifdef CONFIG_DEBUG_VM
1391 pr_alert("failed to isolate pfn %lx\n", pfn);
1392 dump_page(page, "isolation failed");
1395 /* Because we don't have big zone->lock. we should
1396 check this again here. */
1397 if (page_count(page)) {
1404 if (!list_empty(&source)) {
1406 putback_movable_pages(&source);
1410 /* Allocate a new page from the nearest neighbor node */
1411 ret = migrate_pages(&source, new_node_page, NULL, 0,
1412 MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1414 putback_movable_pages(&source);
1421 * remove from free_area[] and mark all as Reserved.
1424 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1427 __offline_isolated_pages(start, start + nr_pages);
1432 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1434 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1435 offline_isolated_pages_cb);
1439 * Check all pages in range, recoreded as memory resource, are isolated.
1442 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1446 long offlined = *(long *)data;
1447 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1448 offlined = nr_pages;
1450 *(long *)data += offlined;
1455 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1460 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1461 check_pages_isolated_cb);
1463 offlined = (long)ret;
1467 static int __init cmdline_parse_movable_node(char *p)
1469 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1470 movable_node_enabled = true;
1472 pr_warn("movable_node parameter depends on CONFIG_HAVE_MEMBLOCK_NODE_MAP to work properly\n");
1476 early_param("movable_node", cmdline_parse_movable_node);
1478 /* check which state of node_states will be changed when offline memory */
1479 static void node_states_check_changes_offline(unsigned long nr_pages,
1480 struct zone *zone, struct memory_notify *arg)
1482 struct pglist_data *pgdat = zone->zone_pgdat;
1483 unsigned long present_pages = 0;
1486 arg->status_change_nid = -1;
1487 arg->status_change_nid_normal = -1;
1488 arg->status_change_nid_high = -1;
1491 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1492 * If the memory to be offline is within the range
1493 * [0..ZONE_NORMAL], and it is the last present memory there,
1494 * the zones in that range will become empty after the offlining,
1495 * thus we can determine that we need to clear the node from
1496 * node_states[N_NORMAL_MEMORY].
1498 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1499 present_pages += pgdat->node_zones[zt].present_pages;
1500 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
1501 arg->status_change_nid_normal = zone_to_nid(zone);
1503 #ifdef CONFIG_HIGHMEM
1505 * node_states[N_HIGH_MEMORY] contains nodes which
1506 * have normal memory or high memory.
1507 * Here we add the present_pages belonging to ZONE_HIGHMEM.
1508 * If the zone is within the range of [0..ZONE_HIGHMEM), and
1509 * we determine that the zones in that range become empty,
1510 * we need to clear the node for N_HIGH_MEMORY.
1512 present_pages += pgdat->node_zones[ZONE_HIGHMEM].present_pages;
1513 if (zone_idx(zone) <= ZONE_HIGHMEM && nr_pages >= present_pages)
1514 arg->status_change_nid_high = zone_to_nid(zone);
1518 * We have accounted the pages from [0..ZONE_NORMAL), and
1519 * in case of CONFIG_HIGHMEM the pages from ZONE_HIGHMEM
1521 * Here we count the possible pages from ZONE_MOVABLE.
1522 * If after having accounted all the pages, we see that the nr_pages
1523 * to be offlined is over or equal to the accounted pages,
1524 * we know that the node will become empty, and so, we can clear
1525 * it for N_MEMORY as well.
1527 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
1529 if (nr_pages >= present_pages)
1530 arg->status_change_nid = zone_to_nid(zone);
1533 static void node_states_clear_node(int node, struct memory_notify *arg)
1535 if (arg->status_change_nid_normal >= 0)
1536 node_clear_state(node, N_NORMAL_MEMORY);
1538 if (arg->status_change_nid_high >= 0)
1539 node_clear_state(node, N_HIGH_MEMORY);
1541 if (arg->status_change_nid >= 0)
1542 node_clear_state(node, N_MEMORY);
1545 static int __ref __offline_pages(unsigned long start_pfn,
1546 unsigned long end_pfn)
1548 unsigned long pfn, nr_pages;
1549 long offlined_pages;
1551 unsigned long flags;
1552 unsigned long valid_start, valid_end;
1554 struct memory_notify arg;
1556 /* at least, alignment against pageblock is necessary */
1557 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1559 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1562 mem_hotplug_begin();
1564 /* This makes hotplug much easier...and readable.
1565 we assume this for now. .*/
1566 if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start,
1572 zone = page_zone(pfn_to_page(valid_start));
1573 node = zone_to_nid(zone);
1574 nr_pages = end_pfn - start_pfn;
1576 /* set above range as isolated */
1577 ret = start_isolate_page_range(start_pfn, end_pfn,
1578 MIGRATE_MOVABLE, true);
1584 arg.start_pfn = start_pfn;
1585 arg.nr_pages = nr_pages;
1586 node_states_check_changes_offline(nr_pages, zone, &arg);
1588 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1589 ret = notifier_to_errno(ret);
1591 goto failed_removal;
1595 /* start memory hot removal */
1597 if (signal_pending(current))
1598 goto failed_removal;
1601 lru_add_drain_all();
1602 drain_all_pages(zone);
1604 pfn = scan_movable_pages(start_pfn, end_pfn);
1605 if (pfn) { /* We have movable pages */
1606 ret = do_migrate_range(pfn, end_pfn);
1611 * dissolve free hugepages in the memory block before doing offlining
1612 * actually in order to make hugetlbfs's object counting consistent.
1614 ret = dissolve_free_huge_pages(start_pfn, end_pfn);
1616 goto failed_removal;
1618 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1619 if (offlined_pages < 0)
1621 pr_info("Offlined Pages %ld\n", offlined_pages);
1622 /* Ok, all of our target is isolated.
1623 We cannot do rollback at this point. */
1624 offline_isolated_pages(start_pfn, end_pfn);
1625 /* reset pagetype flags and makes migrate type to be MOVABLE */
1626 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1627 /* removal success */
1628 adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
1629 zone->present_pages -= offlined_pages;
1631 pgdat_resize_lock(zone->zone_pgdat, &flags);
1632 zone->zone_pgdat->node_present_pages -= offlined_pages;
1633 pgdat_resize_unlock(zone->zone_pgdat, &flags);
1635 init_per_zone_wmark_min();
1637 if (!populated_zone(zone)) {
1638 zone_pcp_reset(zone);
1639 build_all_zonelists(NULL);
1641 zone_pcp_update(zone);
1643 node_states_clear_node(node, &arg);
1644 if (arg.status_change_nid >= 0) {
1646 kcompactd_stop(node);
1649 vm_total_pages = nr_free_pagecache_pages();
1650 writeback_set_ratelimit();
1652 memory_notify(MEM_OFFLINE, &arg);
1657 pr_debug("memory offlining [mem %#010llx-%#010llx] failed\n",
1658 (unsigned long long) start_pfn << PAGE_SHIFT,
1659 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1660 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1661 /* pushback to free area */
1662 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1667 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1669 return __offline_pages(start_pfn, start_pfn + nr_pages);
1671 #endif /* CONFIG_MEMORY_HOTREMOVE */
1674 * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
1675 * @start_pfn: start pfn of the memory range
1676 * @end_pfn: end pfn of the memory range
1677 * @arg: argument passed to func
1678 * @func: callback for each memory section walked
1680 * This function walks through all present mem sections in range
1681 * [start_pfn, end_pfn) and call func on each mem section.
1683 * Returns the return value of func.
1685 int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
1686 void *arg, int (*func)(struct memory_block *, void *))
1688 struct memory_block *mem = NULL;
1689 struct mem_section *section;
1690 unsigned long pfn, section_nr;
1693 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1694 section_nr = pfn_to_section_nr(pfn);
1695 if (!present_section_nr(section_nr))
1698 section = __nr_to_section(section_nr);
1699 /* same memblock? */
1701 if ((section_nr >= mem->start_section_nr) &&
1702 (section_nr <= mem->end_section_nr))
1705 mem = find_memory_block_hinted(section, mem);
1709 ret = func(mem, arg);
1711 kobject_put(&mem->dev.kobj);
1717 kobject_put(&mem->dev.kobj);
1722 #ifdef CONFIG_MEMORY_HOTREMOVE
1723 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1725 int ret = !is_memblock_offlined(mem);
1727 if (unlikely(ret)) {
1728 phys_addr_t beginpa, endpa;
1730 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1731 endpa = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1;
1732 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1739 static int check_cpu_on_node(pg_data_t *pgdat)
1743 for_each_present_cpu(cpu) {
1744 if (cpu_to_node(cpu) == pgdat->node_id)
1746 * the cpu on this node isn't removed, and we can't
1747 * offline this node.
1755 static void unmap_cpu_on_node(pg_data_t *pgdat)
1757 #ifdef CONFIG_ACPI_NUMA
1760 for_each_possible_cpu(cpu)
1761 if (cpu_to_node(cpu) == pgdat->node_id)
1762 numa_clear_node(cpu);
1766 static int check_and_unmap_cpu_on_node(pg_data_t *pgdat)
1770 ret = check_cpu_on_node(pgdat);
1775 * the node will be offlined when we come here, so we can clear
1776 * the cpu_to_node() now.
1779 unmap_cpu_on_node(pgdat);
1787 * Offline a node if all memory sections and cpus of the node are removed.
1789 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1790 * and online/offline operations before this call.
1792 void try_offline_node(int nid)
1794 pg_data_t *pgdat = NODE_DATA(nid);
1795 unsigned long start_pfn = pgdat->node_start_pfn;
1796 unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
1799 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1800 unsigned long section_nr = pfn_to_section_nr(pfn);
1802 if (!present_section_nr(section_nr))
1805 if (pfn_to_nid(pfn) != nid)
1809 * some memory sections of this node are not removed, and we
1810 * can't offline node now.
1815 if (check_and_unmap_cpu_on_node(pgdat))
1819 * all memory/cpu of this node are removed, we can offline this
1822 node_set_offline(nid);
1823 unregister_one_node(nid);
1825 EXPORT_SYMBOL(try_offline_node);
1830 * @start: physical address of the region to remove
1831 * @size: size of the region to remove
1833 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1834 * and online/offline operations before this call, as required by
1835 * try_offline_node().
1837 void __ref __remove_memory(int nid, u64 start, u64 size)
1841 BUG_ON(check_hotplug_memory_range(start, size));
1843 mem_hotplug_begin();
1846 * All memory blocks must be offlined before removing memory. Check
1847 * whether all memory blocks in question are offline and trigger a BUG()
1848 * if this is not the case.
1850 ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
1851 check_memblock_offlined_cb);
1855 /* remove memmap entry */
1856 firmware_map_remove(start, start + size, "System RAM");
1857 memblock_free(start, size);
1858 memblock_remove(start, size);
1860 arch_remove_memory(start, size, NULL);
1862 try_offline_node(nid);
1867 void remove_memory(int nid, u64 start, u64 size)
1869 lock_device_hotplug();
1870 __remove_memory(nid, start, size);
1871 unlock_device_hotplug();
1873 EXPORT_SYMBOL_GPL(remove_memory);
1874 #endif /* CONFIG_MEMORY_HOTREMOVE */