1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/mm/memory_hotplug.c
8 #include <linux/stddef.h>
10 #include <linux/sched/signal.h>
11 #include <linux/swap.h>
12 #include <linux/interrupt.h>
13 #include <linux/pagemap.h>
14 #include <linux/compiler.h>
15 #include <linux/export.h>
16 #include <linux/pagevec.h>
17 #include <linux/writeback.h>
18 #include <linux/slab.h>
19 #include <linux/sysctl.h>
20 #include <linux/cpu.h>
21 #include <linux/memory.h>
22 #include <linux/memremap.h>
23 #include <linux/memory_hotplug.h>
24 #include <linux/highmem.h>
25 #include <linux/vmalloc.h>
26 #include <linux/ioport.h>
27 #include <linux/delay.h>
28 #include <linux/migrate.h>
29 #include <linux/page-isolation.h>
30 #include <linux/pfn.h>
31 #include <linux/suspend.h>
32 #include <linux/mm_inline.h>
33 #include <linux/firmware-map.h>
34 #include <linux/stop_machine.h>
35 #include <linux/hugetlb.h>
36 #include <linux/memblock.h>
37 #include <linux/compaction.h>
38 #include <linux/rmap.h>
40 #include <asm/tlbflush.h>
46 * online_page_callback contains pointer to current page onlining function.
47 * Initially it is generic_online_page(). If it is required it could be
48 * changed by calling set_online_page_callback() for callback registration
49 * and restore_online_page_callback() for generic callback restore.
52 static void generic_online_page(struct page *page, unsigned int order);
54 static online_page_callback_t online_page_callback = generic_online_page;
55 static DEFINE_MUTEX(online_page_callback_lock);
57 DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
59 void get_online_mems(void)
61 percpu_down_read(&mem_hotplug_lock);
64 void put_online_mems(void)
66 percpu_up_read(&mem_hotplug_lock);
69 bool movable_node_enabled = false;
71 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
72 bool memhp_auto_online;
74 bool memhp_auto_online = true;
76 EXPORT_SYMBOL_GPL(memhp_auto_online);
78 static int __init setup_memhp_default_state(char *str)
80 if (!strcmp(str, "online"))
81 memhp_auto_online = true;
82 else if (!strcmp(str, "offline"))
83 memhp_auto_online = false;
87 __setup("memhp_default_state=", setup_memhp_default_state);
89 void mem_hotplug_begin(void)
92 percpu_down_write(&mem_hotplug_lock);
95 void mem_hotplug_done(void)
97 percpu_up_write(&mem_hotplug_lock);
101 u64 max_mem_size = U64_MAX;
103 /* add this memory to iomem resource */
104 static struct resource *register_memory_resource(u64 start, u64 size)
106 struct resource *res;
107 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
108 char *resource_name = "System RAM";
110 if (start + size > max_mem_size)
111 return ERR_PTR(-E2BIG);
114 * Request ownership of the new memory range. This might be
115 * a child of an existing resource that was present but
116 * not marked as busy.
118 res = __request_region(&iomem_resource, start, size,
119 resource_name, flags);
122 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
123 start, start + size);
124 return ERR_PTR(-EEXIST);
129 static void release_memory_resource(struct resource *res)
133 release_resource(res);
137 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
138 void get_page_bootmem(unsigned long info, struct page *page,
141 page->freelist = (void *)type;
142 SetPagePrivate(page);
143 set_page_private(page, info);
147 void put_page_bootmem(struct page *page)
151 type = (unsigned long) page->freelist;
152 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
153 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
155 if (page_ref_dec_return(page) == 1) {
156 page->freelist = NULL;
157 ClearPagePrivate(page);
158 set_page_private(page, 0);
159 INIT_LIST_HEAD(&page->lru);
160 free_reserved_page(page);
164 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
165 #ifndef CONFIG_SPARSEMEM_VMEMMAP
166 static void register_page_bootmem_info_section(unsigned long start_pfn)
168 unsigned long mapsize, section_nr, i;
169 struct mem_section *ms;
170 struct page *page, *memmap;
171 struct mem_section_usage *usage;
173 section_nr = pfn_to_section_nr(start_pfn);
174 ms = __nr_to_section(section_nr);
176 /* Get section's memmap address */
177 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
180 * Get page for the memmap's phys address
181 * XXX: need more consideration for sparse_vmemmap...
183 page = virt_to_page(memmap);
184 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
185 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
187 /* remember memmap's page */
188 for (i = 0; i < mapsize; i++, page++)
189 get_page_bootmem(section_nr, page, SECTION_INFO);
192 page = virt_to_page(usage);
194 mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT;
196 for (i = 0; i < mapsize; i++, page++)
197 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
200 #else /* CONFIG_SPARSEMEM_VMEMMAP */
201 static void register_page_bootmem_info_section(unsigned long start_pfn)
203 unsigned long mapsize, section_nr, i;
204 struct mem_section *ms;
205 struct page *page, *memmap;
206 struct mem_section_usage *usage;
208 section_nr = pfn_to_section_nr(start_pfn);
209 ms = __nr_to_section(section_nr);
211 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
213 register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
216 page = virt_to_page(usage);
218 mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT;
220 for (i = 0; i < mapsize; i++, page++)
221 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
223 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
225 void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
227 unsigned long i, pfn, end_pfn, nr_pages;
228 int node = pgdat->node_id;
231 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
232 page = virt_to_page(pgdat);
234 for (i = 0; i < nr_pages; i++, page++)
235 get_page_bootmem(node, page, NODE_INFO);
237 pfn = pgdat->node_start_pfn;
238 end_pfn = pgdat_end_pfn(pgdat);
240 /* register section info */
241 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
243 * Some platforms can assign the same pfn to multiple nodes - on
244 * node0 as well as nodeN. To avoid registering a pfn against
245 * multiple nodes we check that this pfn does not already
246 * reside in some other nodes.
248 if (pfn_valid(pfn) && (early_pfn_to_nid(pfn) == node))
249 register_page_bootmem_info_section(pfn);
252 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
254 static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
258 * Disallow all operations smaller than a sub-section and only
259 * allow operations smaller than a section for
260 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
261 * enforces a larger memory_block_size_bytes() granularity for
262 * memory that will be marked online, so this check should only
263 * fire for direct arch_{add,remove}_memory() users outside of
264 * add_memory_resource().
266 unsigned long min_align;
268 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
269 min_align = PAGES_PER_SUBSECTION;
271 min_align = PAGES_PER_SECTION;
272 if (!IS_ALIGNED(pfn, min_align)
273 || !IS_ALIGNED(nr_pages, min_align)) {
274 WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n",
275 reason, pfn, pfn + nr_pages - 1);
282 * Reasonably generic function for adding memory. It is
283 * expected that archs that support memory hotplug will
284 * call this function after deciding the zone to which to
287 int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
288 struct mhp_restrictions *restrictions)
291 unsigned long nr, start_sec, end_sec;
292 struct vmem_altmap *altmap = restrictions->altmap;
296 * Validate altmap is within bounds of the total request
298 if (altmap->base_pfn != pfn
299 || vmem_altmap_offset(altmap) > nr_pages) {
300 pr_warn_once("memory add fail, invalid altmap\n");
306 err = check_pfn_span(pfn, nr_pages, "add");
310 start_sec = pfn_to_section_nr(pfn);
311 end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
312 for (nr = start_sec; nr <= end_sec; nr++) {
315 pfns = min(nr_pages, PAGES_PER_SECTION
316 - (pfn & ~PAGE_SECTION_MASK));
317 err = sparse_add_section(nid, pfn, pfns, altmap);
324 vmemmap_populate_print_last();
328 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
329 static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
330 unsigned long start_pfn,
331 unsigned long end_pfn)
333 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
334 if (unlikely(!pfn_to_online_page(start_pfn)))
337 if (unlikely(pfn_to_nid(start_pfn) != nid))
340 if (zone && zone != page_zone(pfn_to_page(start_pfn)))
349 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
350 static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
351 unsigned long start_pfn,
352 unsigned long end_pfn)
356 /* pfn is the end pfn of a memory section. */
358 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) {
359 if (unlikely(!pfn_to_online_page(pfn)))
362 if (unlikely(pfn_to_nid(pfn) != nid))
365 if (zone && zone != page_zone(pfn_to_page(pfn)))
374 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
375 unsigned long end_pfn)
377 unsigned long zone_start_pfn = zone->zone_start_pfn;
378 unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
379 unsigned long zone_end_pfn = z;
381 int nid = zone_to_nid(zone);
383 zone_span_writelock(zone);
384 if (zone_start_pfn == start_pfn) {
386 * If the section is smallest section in the zone, it need
387 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
388 * In this case, we find second smallest valid mem_section
389 * for shrinking zone.
391 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
394 zone->zone_start_pfn = pfn;
395 zone->spanned_pages = zone_end_pfn - pfn;
397 } else if (zone_end_pfn == end_pfn) {
399 * If the section is biggest section in the zone, it need
400 * shrink zone->spanned_pages.
401 * In this case, we find second biggest valid mem_section for
404 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
407 zone->spanned_pages = pfn - zone_start_pfn + 1;
411 * The section is not biggest or smallest mem_section in the zone, it
412 * only creates a hole in the zone. So in this case, we need not
413 * change the zone. But perhaps, the zone has only hole data. Thus
414 * it check the zone has only hole or not.
416 pfn = zone_start_pfn;
417 for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUBSECTION) {
418 if (unlikely(!pfn_to_online_page(pfn)))
421 if (page_zone(pfn_to_page(pfn)) != zone)
424 /* Skip range to be removed */
425 if (pfn >= start_pfn && pfn < end_pfn)
428 /* If we find valid section, we have nothing to do */
429 zone_span_writeunlock(zone);
433 /* The zone has no valid section */
434 zone->zone_start_pfn = 0;
435 zone->spanned_pages = 0;
436 zone_span_writeunlock(zone);
439 static void update_pgdat_span(struct pglist_data *pgdat)
441 unsigned long node_start_pfn = 0, node_end_pfn = 0;
444 for (zone = pgdat->node_zones;
445 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
446 unsigned long zone_end_pfn = zone->zone_start_pfn +
449 /* No need to lock the zones, they can't change. */
450 if (!zone->spanned_pages)
453 node_start_pfn = zone->zone_start_pfn;
454 node_end_pfn = zone_end_pfn;
458 if (zone_end_pfn > node_end_pfn)
459 node_end_pfn = zone_end_pfn;
460 if (zone->zone_start_pfn < node_start_pfn)
461 node_start_pfn = zone->zone_start_pfn;
464 pgdat->node_start_pfn = node_start_pfn;
465 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
468 void __ref remove_pfn_range_from_zone(struct zone *zone,
469 unsigned long start_pfn,
470 unsigned long nr_pages)
472 struct pglist_data *pgdat = zone->zone_pgdat;
475 #ifdef CONFIG_ZONE_DEVICE
477 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
478 * we will not try to shrink the zones - which is okay as
479 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
481 if (zone_idx(zone) == ZONE_DEVICE)
485 clear_zone_contiguous(zone);
487 pgdat_resize_lock(zone->zone_pgdat, &flags);
488 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
489 update_pgdat_span(pgdat);
490 pgdat_resize_unlock(zone->zone_pgdat, &flags);
492 set_zone_contiguous(zone);
495 static void __remove_section(unsigned long pfn, unsigned long nr_pages,
496 unsigned long map_offset,
497 struct vmem_altmap *altmap)
499 struct mem_section *ms = __nr_to_section(pfn_to_section_nr(pfn));
501 if (WARN_ON_ONCE(!valid_section(ms)))
504 sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap);
508 * __remove_pages() - remove sections of pages
509 * @pfn: starting pageframe (must be aligned to start of a section)
510 * @nr_pages: number of pages to remove (must be multiple of section size)
511 * @altmap: alternative device page map or %NULL if default memmap is used
513 * Generic helper function to remove section mappings and sysfs entries
514 * for the section of the memory we are removing. Caller needs to make
515 * sure that pages are marked reserved and zones are adjust properly by
516 * calling offline_pages().
518 void __remove_pages(unsigned long pfn, unsigned long nr_pages,
519 struct vmem_altmap *altmap)
521 unsigned long map_offset = 0;
522 unsigned long nr, start_sec, end_sec;
524 map_offset = vmem_altmap_offset(altmap);
526 if (check_pfn_span(pfn, nr_pages, "remove"))
529 start_sec = pfn_to_section_nr(pfn);
530 end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
531 for (nr = start_sec; nr <= end_sec; nr++) {
535 pfns = min(nr_pages, PAGES_PER_SECTION
536 - (pfn & ~PAGE_SECTION_MASK));
537 __remove_section(pfn, pfns, map_offset, altmap);
544 int set_online_page_callback(online_page_callback_t callback)
549 mutex_lock(&online_page_callback_lock);
551 if (online_page_callback == generic_online_page) {
552 online_page_callback = callback;
556 mutex_unlock(&online_page_callback_lock);
561 EXPORT_SYMBOL_GPL(set_online_page_callback);
563 int restore_online_page_callback(online_page_callback_t callback)
568 mutex_lock(&online_page_callback_lock);
570 if (online_page_callback == callback) {
571 online_page_callback = generic_online_page;
575 mutex_unlock(&online_page_callback_lock);
580 EXPORT_SYMBOL_GPL(restore_online_page_callback);
582 void __online_page_set_limits(struct page *page)
585 EXPORT_SYMBOL_GPL(__online_page_set_limits);
587 void __online_page_increment_counters(struct page *page)
589 adjust_managed_page_count(page, 1);
591 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
593 void __online_page_free(struct page *page)
595 __free_reserved_page(page);
597 EXPORT_SYMBOL_GPL(__online_page_free);
599 static void generic_online_page(struct page *page, unsigned int order)
601 kernel_map_pages(page, 1 << order, 1);
602 __free_pages_core(page, order);
603 totalram_pages_add(1UL << order);
604 #ifdef CONFIG_HIGHMEM
605 if (PageHighMem(page))
606 totalhigh_pages_add(1UL << order);
610 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
613 const unsigned long end_pfn = start_pfn + nr_pages;
618 * Online the pages. The callback might decide to keep some pages
619 * PG_reserved (to add them to the buddy later), but we still account
620 * them as being online/belonging to this zone ("present").
622 for (pfn = start_pfn; pfn < end_pfn; pfn += 1ul << order) {
623 order = min(MAX_ORDER - 1, get_order(PFN_PHYS(end_pfn - pfn)));
624 /* __free_pages_core() wants pfns to be aligned to the order */
625 if (WARN_ON_ONCE(!IS_ALIGNED(pfn, 1ul << order)))
627 (*online_page_callback)(pfn_to_page(pfn), order);
630 /* mark all involved sections as online */
631 online_mem_sections(start_pfn, end_pfn);
633 *(unsigned long *)arg += nr_pages;
637 /* check which state of node_states will be changed when online memory */
638 static void node_states_check_changes_online(unsigned long nr_pages,
639 struct zone *zone, struct memory_notify *arg)
641 int nid = zone_to_nid(zone);
643 arg->status_change_nid = NUMA_NO_NODE;
644 arg->status_change_nid_normal = NUMA_NO_NODE;
645 arg->status_change_nid_high = NUMA_NO_NODE;
647 if (!node_state(nid, N_MEMORY))
648 arg->status_change_nid = nid;
649 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
650 arg->status_change_nid_normal = nid;
651 #ifdef CONFIG_HIGHMEM
652 if (zone_idx(zone) <= ZONE_HIGHMEM && !node_state(nid, N_HIGH_MEMORY))
653 arg->status_change_nid_high = nid;
657 static void node_states_set_node(int node, struct memory_notify *arg)
659 if (arg->status_change_nid_normal >= 0)
660 node_set_state(node, N_NORMAL_MEMORY);
662 if (arg->status_change_nid_high >= 0)
663 node_set_state(node, N_HIGH_MEMORY);
665 if (arg->status_change_nid >= 0)
666 node_set_state(node, N_MEMORY);
669 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
670 unsigned long nr_pages)
672 unsigned long old_end_pfn = zone_end_pfn(zone);
674 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
675 zone->zone_start_pfn = start_pfn;
677 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
680 static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
681 unsigned long nr_pages)
683 unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
685 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
686 pgdat->node_start_pfn = start_pfn;
688 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
692 * Associate the pfn range with the given zone, initializing the memmaps
693 * and resizing the pgdat/zone data to span the added pages. After this
694 * call, all affected pages are PG_reserved.
696 void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
697 unsigned long nr_pages, struct vmem_altmap *altmap)
699 struct pglist_data *pgdat = zone->zone_pgdat;
700 int nid = pgdat->node_id;
703 clear_zone_contiguous(zone);
705 /* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */
706 pgdat_resize_lock(pgdat, &flags);
707 zone_span_writelock(zone);
708 if (zone_is_empty(zone))
709 init_currently_empty_zone(zone, start_pfn, nr_pages);
710 resize_zone_range(zone, start_pfn, nr_pages);
711 zone_span_writeunlock(zone);
712 resize_pgdat_range(pgdat, start_pfn, nr_pages);
713 pgdat_resize_unlock(pgdat, &flags);
716 * TODO now we have a visible range of pages which are not associated
717 * with their zone properly. Not nice but set_pfnblock_flags_mask
718 * expects the zone spans the pfn range. All the pages in the range
719 * are reserved so nobody should be touching them so we should be safe
721 memmap_init_zone(nr_pages, nid, zone_idx(zone), start_pfn,
722 MEMMAP_HOTPLUG, altmap);
724 set_zone_contiguous(zone);
728 * Returns a default kernel memory zone for the given pfn range.
729 * If no kernel zone covers this pfn range it will automatically go
730 * to the ZONE_NORMAL.
732 static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
733 unsigned long nr_pages)
735 struct pglist_data *pgdat = NODE_DATA(nid);
738 for (zid = 0; zid <= ZONE_NORMAL; zid++) {
739 struct zone *zone = &pgdat->node_zones[zid];
741 if (zone_intersects(zone, start_pfn, nr_pages))
745 return &pgdat->node_zones[ZONE_NORMAL];
748 static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
749 unsigned long nr_pages)
751 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
753 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
754 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
755 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
758 * We inherit the existing zone in a simple case where zones do not
759 * overlap in the given range
761 if (in_kernel ^ in_movable)
762 return (in_kernel) ? kernel_zone : movable_zone;
765 * If the range doesn't belong to any zone or two zones overlap in the
766 * given range then we use movable zone only if movable_node is
767 * enabled because we always online to a kernel zone by default.
769 return movable_node_enabled ? movable_zone : kernel_zone;
772 struct zone * zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
773 unsigned long nr_pages)
775 if (online_type == MMOP_ONLINE_KERNEL)
776 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
778 if (online_type == MMOP_ONLINE_MOVABLE)
779 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
781 return default_zone_for_pfn(nid, start_pfn, nr_pages);
784 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
787 unsigned long onlined_pages = 0;
789 int need_zonelists_rebuild = 0;
792 struct memory_notify arg;
793 struct memory_block *mem;
798 * We can't use pfn_to_nid() because nid might be stored in struct page
799 * which is not yet initialized. Instead, we find nid from memory block.
801 mem = find_memory_block(__pfn_to_section(pfn));
803 put_device(&mem->dev);
805 /* associate pfn range with the zone */
806 zone = zone_for_pfn_range(online_type, nid, pfn, nr_pages);
807 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL);
810 arg.nr_pages = nr_pages;
811 node_states_check_changes_online(nr_pages, zone, &arg);
813 ret = memory_notify(MEM_GOING_ONLINE, &arg);
814 ret = notifier_to_errno(ret);
816 goto failed_addition;
819 * If this zone is not populated, then it is not in zonelist.
820 * This means the page allocator ignores this zone.
821 * So, zonelist must be updated after online.
823 if (!populated_zone(zone)) {
824 need_zonelists_rebuild = 1;
825 setup_zone_pageset(zone);
828 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
831 /* not a single memory resource was applicable */
832 if (need_zonelists_rebuild)
833 zone_pcp_reset(zone);
834 goto failed_addition;
837 zone->present_pages += onlined_pages;
839 pgdat_resize_lock(zone->zone_pgdat, &flags);
840 zone->zone_pgdat->node_present_pages += onlined_pages;
841 pgdat_resize_unlock(zone->zone_pgdat, &flags);
845 node_states_set_node(nid, &arg);
846 if (need_zonelists_rebuild)
847 build_all_zonelists(NULL);
849 zone_pcp_update(zone);
851 init_per_zone_wmark_min();
856 vm_total_pages = nr_free_pagecache_pages();
858 writeback_set_ratelimit();
860 memory_notify(MEM_ONLINE, &arg);
865 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
866 (unsigned long long) pfn << PAGE_SHIFT,
867 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
868 memory_notify(MEM_CANCEL_ONLINE, &arg);
869 remove_pfn_range_from_zone(zone, pfn, nr_pages);
873 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
875 static void reset_node_present_pages(pg_data_t *pgdat)
879 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
880 z->present_pages = 0;
882 pgdat->node_present_pages = 0;
885 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
886 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
888 struct pglist_data *pgdat;
889 unsigned long start_pfn = PFN_DOWN(start);
891 pgdat = NODE_DATA(nid);
893 pgdat = arch_alloc_nodedata(nid);
897 pgdat->per_cpu_nodestats =
898 alloc_percpu(struct per_cpu_nodestat);
899 arch_refresh_nodedata(nid, pgdat);
903 * Reset the nr_zones, order and classzone_idx before reuse.
904 * Note that kswapd will init kswapd_classzone_idx properly
905 * when it starts in the near future.
908 pgdat->kswapd_order = 0;
909 pgdat->kswapd_classzone_idx = 0;
910 for_each_online_cpu(cpu) {
911 struct per_cpu_nodestat *p;
913 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
914 memset(p, 0, sizeof(*p));
918 /* we can use NODE_DATA(nid) from here */
920 pgdat->node_id = nid;
921 pgdat->node_start_pfn = start_pfn;
923 /* init node's zones as empty zones, we don't have any present pages.*/
924 free_area_init_core_hotplug(nid);
927 * The node we allocated has no zone fallback lists. For avoiding
928 * to access not-initialized zonelist, build here.
930 build_all_zonelists(pgdat);
933 * When memory is hot-added, all the memory is in offline state. So
934 * clear all zones' present_pages because they will be updated in
935 * online_pages() and offline_pages().
937 reset_node_managed_pages(pgdat);
938 reset_node_present_pages(pgdat);
943 static void rollback_node_hotadd(int nid)
945 pg_data_t *pgdat = NODE_DATA(nid);
947 arch_refresh_nodedata(nid, NULL);
948 free_percpu(pgdat->per_cpu_nodestats);
949 arch_free_nodedata(pgdat);
954 * try_online_node - online a node if offlined
956 * @start: start addr of the node
957 * @set_node_online: Whether we want to online the node
958 * called by cpu_up() to online a node without onlined memory.
961 * 1 -> a new node has been allocated
962 * 0 -> the node is already online
963 * -ENOMEM -> the node could not be allocated
965 static int __try_online_node(int nid, u64 start, bool set_node_online)
970 if (node_online(nid))
973 pgdat = hotadd_new_pgdat(nid, start);
975 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
980 if (set_node_online) {
981 node_set_online(nid);
982 ret = register_one_node(nid);
990 * Users of this function always want to online/register the node
992 int try_online_node(int nid)
997 ret = __try_online_node(nid, 0, true);
1002 static int check_hotplug_memory_range(u64 start, u64 size)
1004 /* memory range must be block size aligned */
1005 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
1006 !IS_ALIGNED(size, memory_block_size_bytes())) {
1007 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1008 memory_block_size_bytes(), start, size);
1015 static int online_memory_block(struct memory_block *mem, void *arg)
1017 return device_online(&mem->dev);
1021 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1022 * and online/offline operations (triggered e.g. by sysfs).
1024 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1026 int __ref add_memory_resource(int nid, struct resource *res)
1028 struct mhp_restrictions restrictions = {};
1030 bool new_node = false;
1034 size = resource_size(res);
1036 ret = check_hotplug_memory_range(start, size);
1040 mem_hotplug_begin();
1043 * Add new range to memblock so that when hotadd_new_pgdat() is called
1044 * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
1045 * this new range and calculate total pages correctly. The range will
1046 * be removed at hot-remove time.
1048 memblock_add_node(start, size, nid);
1050 ret = __try_online_node(nid, start, false);
1055 /* call arch's memory hotadd */
1056 ret = arch_add_memory(nid, start, size, &restrictions);
1060 /* create memory block devices after memory was added */
1061 ret = create_memory_block_devices(start, size);
1063 arch_remove_memory(nid, start, size, NULL);
1068 /* If sysfs file of new node can't be created, cpu on the node
1069 * can't be hot-added. There is no rollback way now.
1070 * So, check by BUG_ON() to catch it reluctantly..
1071 * We online node here. We can't roll back from here.
1073 node_set_online(nid);
1074 ret = __register_one_node(nid);
1078 /* link memory sections under this node.*/
1079 ret = link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1));
1082 /* create new memmap entry */
1083 firmware_map_add_hotplug(start, start + size, "System RAM");
1085 /* device_online() will take the lock when calling online_pages() */
1088 /* online pages if requested */
1089 if (memhp_auto_online)
1090 walk_memory_blocks(start, size, NULL, online_memory_block);
1094 /* rollback pgdat allocation and others */
1096 rollback_node_hotadd(nid);
1097 memblock_remove(start, size);
1102 /* requires device_hotplug_lock, see add_memory_resource() */
1103 int __ref __add_memory(int nid, u64 start, u64 size)
1105 struct resource *res;
1108 res = register_memory_resource(start, size);
1110 return PTR_ERR(res);
1112 ret = add_memory_resource(nid, res);
1114 release_memory_resource(res);
1118 int add_memory(int nid, u64 start, u64 size)
1122 lock_device_hotplug();
1123 rc = __add_memory(nid, start, size);
1124 unlock_device_hotplug();
1128 EXPORT_SYMBOL_GPL(add_memory);
1130 #ifdef CONFIG_MEMORY_HOTREMOVE
1132 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1133 * set and the size of the free page is given by page_order(). Using this,
1134 * the function determines if the pageblock contains only free pages.
1135 * Due to buddy contraints, a free page at least the size of a pageblock will
1136 * be located at the start of the pageblock
1138 static inline int pageblock_free(struct page *page)
1140 return PageBuddy(page) && page_order(page) >= pageblock_order;
1143 /* Return the pfn of the start of the next active pageblock after a given pfn */
1144 static unsigned long next_active_pageblock(unsigned long pfn)
1146 struct page *page = pfn_to_page(pfn);
1148 /* Ensure the starting page is pageblock-aligned */
1149 BUG_ON(pfn & (pageblock_nr_pages - 1));
1151 /* If the entire pageblock is free, move to the end of free page */
1152 if (pageblock_free(page)) {
1154 /* be careful. we don't have locks, page_order can be changed.*/
1155 order = page_order(page);
1156 if ((order < MAX_ORDER) && (order >= pageblock_order))
1157 return pfn + (1 << order);
1160 return pfn + pageblock_nr_pages;
1163 static bool is_pageblock_removable_nolock(unsigned long pfn)
1165 struct page *page = pfn_to_page(pfn);
1169 * We have to be careful here because we are iterating over memory
1170 * sections which are not zone aware so we might end up outside of
1171 * the zone but still within the section.
1172 * We have to take care about the node as well. If the node is offline
1173 * its NODE_DATA will be NULL - see page_zone.
1175 if (!node_online(page_to_nid(page)))
1178 zone = page_zone(page);
1179 pfn = page_to_pfn(page);
1180 if (!zone_spans_pfn(zone, pfn))
1183 return !has_unmovable_pages(zone, page, 0, MIGRATE_MOVABLE, SKIP_HWPOISON);
1186 /* Checks if this range of memory is likely to be hot-removable. */
1187 bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1189 unsigned long end_pfn, pfn;
1191 end_pfn = min(start_pfn + nr_pages,
1192 zone_end_pfn(page_zone(pfn_to_page(start_pfn))));
1194 /* Check the starting page of each pageblock within the range */
1195 for (pfn = start_pfn; pfn < end_pfn; pfn = next_active_pageblock(pfn)) {
1196 if (!is_pageblock_removable_nolock(pfn))
1201 /* All pageblocks in the memory block are likely to be hot-removable */
1206 * Confirm all pages in a range [start, end) belong to the same zone.
1207 * When true, return its valid [start, end).
1209 int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
1210 unsigned long *valid_start, unsigned long *valid_end)
1212 unsigned long pfn, sec_end_pfn;
1213 unsigned long start, end;
1214 struct zone *zone = NULL;
1217 for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1);
1219 pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) {
1220 /* Make sure the memory section is present first */
1221 if (!present_section_nr(pfn_to_section_nr(pfn)))
1223 for (; pfn < sec_end_pfn && pfn < end_pfn;
1224 pfn += MAX_ORDER_NR_PAGES) {
1226 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1227 while ((i < MAX_ORDER_NR_PAGES) &&
1228 !pfn_valid_within(pfn + i))
1230 if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn)
1232 /* Check if we got outside of the zone */
1233 if (zone && !zone_spans_pfn(zone, pfn + i))
1235 page = pfn_to_page(pfn + i);
1236 if (zone && page_zone(page) != zone)
1240 zone = page_zone(page);
1241 end = pfn + MAX_ORDER_NR_PAGES;
1246 *valid_start = start;
1247 *valid_end = min(end, end_pfn);
1255 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1256 * non-lru movable pages and hugepages). We scan pfn because it's much
1257 * easier than scanning over linked list. This function returns the pfn
1258 * of the first found movable page if it's found, otherwise 0.
1260 static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1264 for (pfn = start; pfn < end; pfn++) {
1265 struct page *page, *head;
1268 if (!pfn_valid(pfn))
1270 page = pfn_to_page(pfn);
1273 if (__PageMovable(page))
1276 if (!PageHuge(page))
1278 head = compound_head(page);
1279 if (page_huge_active(head))
1281 skip = compound_nr(head) - (page - head);
1287 static struct page *new_node_page(struct page *page, unsigned long private)
1289 int nid = page_to_nid(page);
1290 nodemask_t nmask = node_states[N_MEMORY];
1293 * try to allocate from a different node but reuse this node if there
1294 * are no other online nodes to be used (e.g. we are offlining a part
1295 * of the only existing node)
1297 node_clear(nid, nmask);
1298 if (nodes_empty(nmask))
1299 node_set(nid, nmask);
1301 return new_page_nodemask(page, nid, &nmask);
1305 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1312 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1313 if (!pfn_valid(pfn))
1315 page = pfn_to_page(pfn);
1317 if (PageHuge(page)) {
1318 struct page *head = compound_head(page);
1319 pfn = page_to_pfn(head) + compound_nr(head) - 1;
1320 isolate_huge_page(head, &source);
1322 } else if (PageTransHuge(page))
1323 pfn = page_to_pfn(compound_head(page))
1324 + hpage_nr_pages(page) - 1;
1327 * HWPoison pages have elevated reference counts so the migration would
1328 * fail on them. It also doesn't make any sense to migrate them in the
1329 * first place. Still try to unmap such a page in case it is still mapped
1330 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1331 * the unmap as the catch all safety net).
1333 if (PageHWPoison(page)) {
1334 if (WARN_ON(PageLRU(page)))
1335 isolate_lru_page(page);
1336 if (page_mapped(page))
1337 try_to_unmap(page, TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS);
1341 if (!get_page_unless_zero(page))
1344 * We can skip free pages. And we can deal with pages on
1345 * LRU and non-lru movable pages.
1348 ret = isolate_lru_page(page);
1350 ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
1351 if (!ret) { /* Success */
1352 list_add_tail(&page->lru, &source);
1353 if (!__PageMovable(page))
1354 inc_node_page_state(page, NR_ISOLATED_ANON +
1355 page_is_file_cache(page));
1358 pr_warn("failed to isolate pfn %lx\n", pfn);
1359 dump_page(page, "isolation failed");
1363 if (!list_empty(&source)) {
1364 /* Allocate a new page from the nearest neighbor node */
1365 ret = migrate_pages(&source, new_node_page, NULL, 0,
1366 MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1368 list_for_each_entry(page, &source, lru) {
1369 pr_warn("migrating pfn %lx failed ret:%d ",
1370 page_to_pfn(page), ret);
1371 dump_page(page, "migration failure");
1373 putback_movable_pages(&source);
1381 * remove from free_area[] and mark all as Reserved.
1384 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1387 unsigned long *offlined_pages = (unsigned long *)data;
1389 *offlined_pages += __offline_isolated_pages(start, start + nr_pages);
1394 * Check all pages in range, recoreded as memory resource, are isolated.
1397 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1400 return test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1403 static int __init cmdline_parse_movable_node(char *p)
1405 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1406 movable_node_enabled = true;
1408 pr_warn("movable_node parameter depends on CONFIG_HAVE_MEMBLOCK_NODE_MAP to work properly\n");
1412 early_param("movable_node", cmdline_parse_movable_node);
1414 /* check which state of node_states will be changed when offline memory */
1415 static void node_states_check_changes_offline(unsigned long nr_pages,
1416 struct zone *zone, struct memory_notify *arg)
1418 struct pglist_data *pgdat = zone->zone_pgdat;
1419 unsigned long present_pages = 0;
1422 arg->status_change_nid = NUMA_NO_NODE;
1423 arg->status_change_nid_normal = NUMA_NO_NODE;
1424 arg->status_change_nid_high = NUMA_NO_NODE;
1427 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1428 * If the memory to be offline is within the range
1429 * [0..ZONE_NORMAL], and it is the last present memory there,
1430 * the zones in that range will become empty after the offlining,
1431 * thus we can determine that we need to clear the node from
1432 * node_states[N_NORMAL_MEMORY].
1434 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1435 present_pages += pgdat->node_zones[zt].present_pages;
1436 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
1437 arg->status_change_nid_normal = zone_to_nid(zone);
1439 #ifdef CONFIG_HIGHMEM
1441 * node_states[N_HIGH_MEMORY] contains nodes which
1442 * have normal memory or high memory.
1443 * Here we add the present_pages belonging to ZONE_HIGHMEM.
1444 * If the zone is within the range of [0..ZONE_HIGHMEM), and
1445 * we determine that the zones in that range become empty,
1446 * we need to clear the node for N_HIGH_MEMORY.
1448 present_pages += pgdat->node_zones[ZONE_HIGHMEM].present_pages;
1449 if (zone_idx(zone) <= ZONE_HIGHMEM && nr_pages >= present_pages)
1450 arg->status_change_nid_high = zone_to_nid(zone);
1454 * We have accounted the pages from [0..ZONE_NORMAL), and
1455 * in case of CONFIG_HIGHMEM the pages from ZONE_HIGHMEM
1457 * Here we count the possible pages from ZONE_MOVABLE.
1458 * If after having accounted all the pages, we see that the nr_pages
1459 * to be offlined is over or equal to the accounted pages,
1460 * we know that the node will become empty, and so, we can clear
1461 * it for N_MEMORY as well.
1463 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
1465 if (nr_pages >= present_pages)
1466 arg->status_change_nid = zone_to_nid(zone);
1469 static void node_states_clear_node(int node, struct memory_notify *arg)
1471 if (arg->status_change_nid_normal >= 0)
1472 node_clear_state(node, N_NORMAL_MEMORY);
1474 if (arg->status_change_nid_high >= 0)
1475 node_clear_state(node, N_HIGH_MEMORY);
1477 if (arg->status_change_nid >= 0)
1478 node_clear_state(node, N_MEMORY);
1481 static int __ref __offline_pages(unsigned long start_pfn,
1482 unsigned long end_pfn)
1484 unsigned long pfn, nr_pages;
1485 unsigned long offlined_pages = 0;
1486 int ret, node, nr_isolate_pageblock;
1487 unsigned long flags;
1488 unsigned long valid_start, valid_end;
1490 struct memory_notify arg;
1493 mem_hotplug_begin();
1495 /* This makes hotplug much easier...and readable.
1496 we assume this for now. .*/
1497 if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start,
1500 reason = "multizone range";
1501 goto failed_removal;
1504 zone = page_zone(pfn_to_page(valid_start));
1505 node = zone_to_nid(zone);
1506 nr_pages = end_pfn - start_pfn;
1508 /* set above range as isolated */
1509 ret = start_isolate_page_range(start_pfn, end_pfn,
1511 SKIP_HWPOISON | REPORT_FAILURE);
1513 reason = "failure to isolate range";
1514 goto failed_removal;
1516 nr_isolate_pageblock = ret;
1518 arg.start_pfn = start_pfn;
1519 arg.nr_pages = nr_pages;
1520 node_states_check_changes_offline(nr_pages, zone, &arg);
1522 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1523 ret = notifier_to_errno(ret);
1525 reason = "notifier failure";
1526 goto failed_removal_isolated;
1530 for (pfn = start_pfn; pfn;) {
1531 if (signal_pending(current)) {
1533 reason = "signal backoff";
1534 goto failed_removal_isolated;
1538 lru_add_drain_all();
1540 pfn = scan_movable_pages(pfn, end_pfn);
1543 * TODO: fatal migration failures should bail
1546 do_migrate_range(pfn, end_pfn);
1551 * Dissolve free hugepages in the memory block before doing
1552 * offlining actually in order to make hugetlbfs's object
1553 * counting consistent.
1555 ret = dissolve_free_huge_pages(start_pfn, end_pfn);
1557 reason = "failure to dissolve huge pages";
1558 goto failed_removal_isolated;
1561 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn,
1562 NULL, check_pages_isolated_cb);
1565 /* Ok, all of our target is isolated.
1566 We cannot do rollback at this point. */
1567 walk_system_ram_range(start_pfn, end_pfn - start_pfn,
1568 &offlined_pages, offline_isolated_pages_cb);
1569 pr_info("Offlined Pages %ld\n", offlined_pages);
1571 * Onlining will reset pagetype flags and makes migrate type
1572 * MOVABLE, so just need to decrease the number of isolated
1573 * pageblocks zone counter here.
1575 spin_lock_irqsave(&zone->lock, flags);
1576 zone->nr_isolate_pageblock -= nr_isolate_pageblock;
1577 spin_unlock_irqrestore(&zone->lock, flags);
1579 /* removal success */
1580 adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
1581 zone->present_pages -= offlined_pages;
1583 pgdat_resize_lock(zone->zone_pgdat, &flags);
1584 zone->zone_pgdat->node_present_pages -= offlined_pages;
1585 pgdat_resize_unlock(zone->zone_pgdat, &flags);
1587 init_per_zone_wmark_min();
1589 if (!populated_zone(zone)) {
1590 zone_pcp_reset(zone);
1591 build_all_zonelists(NULL);
1593 zone_pcp_update(zone);
1595 node_states_clear_node(node, &arg);
1596 if (arg.status_change_nid >= 0) {
1598 kcompactd_stop(node);
1601 vm_total_pages = nr_free_pagecache_pages();
1602 writeback_set_ratelimit();
1604 memory_notify(MEM_OFFLINE, &arg);
1605 remove_pfn_range_from_zone(zone, start_pfn, nr_pages);
1609 failed_removal_isolated:
1610 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1611 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1613 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
1614 (unsigned long long) start_pfn << PAGE_SHIFT,
1615 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
1617 /* pushback to free area */
1622 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1624 return __offline_pages(start_pfn, start_pfn + nr_pages);
1627 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1629 int ret = !is_memblock_offlined(mem);
1631 if (unlikely(ret)) {
1632 phys_addr_t beginpa, endpa;
1634 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1635 endpa = beginpa + memory_block_size_bytes() - 1;
1636 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1644 static int check_cpu_on_node(pg_data_t *pgdat)
1648 for_each_present_cpu(cpu) {
1649 if (cpu_to_node(cpu) == pgdat->node_id)
1651 * the cpu on this node isn't removed, and we can't
1652 * offline this node.
1660 static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg)
1662 int nid = *(int *)arg;
1665 * If a memory block belongs to multiple nodes, the stored nid is not
1666 * reliable. However, such blocks are always online (e.g., cannot get
1667 * offlined) and, therefore, are still spanned by the node.
1669 return mem->nid == nid ? -EEXIST : 0;
1676 * Offline a node if all memory sections and cpus of the node are removed.
1678 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1679 * and online/offline operations before this call.
1681 void try_offline_node(int nid)
1683 pg_data_t *pgdat = NODE_DATA(nid);
1687 * If the node still spans pages (especially ZONE_DEVICE), don't
1688 * offline it. A node spans memory after move_pfn_range_to_zone(),
1689 * e.g., after the memory block was onlined.
1691 if (pgdat->node_spanned_pages)
1695 * Especially offline memory blocks might not be spanned by the
1696 * node. They will get spanned by the node once they get onlined.
1697 * However, they link to the node in sysfs and can get onlined later.
1699 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb);
1703 if (check_cpu_on_node(pgdat))
1707 * all memory/cpu of this node are removed, we can offline this
1710 node_set_offline(nid);
1711 unregister_one_node(nid);
1713 EXPORT_SYMBOL(try_offline_node);
1715 static void __release_memory_resource(resource_size_t start,
1716 resource_size_t size)
1721 * When removing memory in the same granularity as it was added,
1722 * this function never fails. It might only fail if resources
1723 * have to be adjusted or split. We'll ignore the error, as
1724 * removing of memory cannot fail.
1726 ret = release_mem_region_adjustable(&iomem_resource, start, size);
1728 resource_size_t endres = start + size - 1;
1730 pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
1731 &start, &endres, ret);
1735 static int __ref try_remove_memory(int nid, u64 start, u64 size)
1739 BUG_ON(check_hotplug_memory_range(start, size));
1741 mem_hotplug_begin();
1744 * All memory blocks must be offlined before removing memory. Check
1745 * whether all memory blocks in question are offline and return error
1746 * if this is not the case.
1748 rc = walk_memory_blocks(start, size, NULL, check_memblock_offlined_cb);
1752 /* remove memmap entry */
1753 firmware_map_remove(start, start + size, "System RAM");
1754 memblock_free(start, size);
1755 memblock_remove(start, size);
1757 /* remove memory block devices before removing memory */
1758 remove_memory_block_devices(start, size);
1760 arch_remove_memory(nid, start, size, NULL);
1761 __release_memory_resource(start, size);
1763 try_offline_node(nid);
1773 * @start: physical address of the region to remove
1774 * @size: size of the region to remove
1776 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1777 * and online/offline operations before this call, as required by
1778 * try_offline_node().
1780 void __remove_memory(int nid, u64 start, u64 size)
1784 * trigger BUG() if some memory is not offlined prior to calling this
1787 if (try_remove_memory(nid, start, size))
1792 * Remove memory if every memory block is offline, otherwise return -EBUSY is
1793 * some memory is not offline
1795 int remove_memory(int nid, u64 start, u64 size)
1799 lock_device_hotplug();
1800 rc = try_remove_memory(nid, start, size);
1801 unlock_device_hotplug();
1805 EXPORT_SYMBOL_GPL(remove_memory);
1806 #endif /* CONFIG_MEMORY_HOTREMOVE */