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 online_page_callback_t online_page_callback = generic_online_page;
53 static DEFINE_MUTEX(online_page_callback_lock);
55 DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
57 void get_online_mems(void)
59 percpu_down_read(&mem_hotplug_lock);
62 void put_online_mems(void)
64 percpu_up_read(&mem_hotplug_lock);
67 bool movable_node_enabled = false;
69 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
70 bool memhp_auto_online;
72 bool memhp_auto_online = true;
74 EXPORT_SYMBOL_GPL(memhp_auto_online);
76 static int __init setup_memhp_default_state(char *str)
78 if (!strcmp(str, "online"))
79 memhp_auto_online = true;
80 else if (!strcmp(str, "offline"))
81 memhp_auto_online = false;
85 __setup("memhp_default_state=", setup_memhp_default_state);
87 void mem_hotplug_begin(void)
90 percpu_down_write(&mem_hotplug_lock);
93 void mem_hotplug_done(void)
95 percpu_up_write(&mem_hotplug_lock);
99 u64 max_mem_size = U64_MAX;
101 /* add this memory to iomem resource */
102 static struct resource *register_memory_resource(u64 start, u64 size)
104 struct resource *res;
105 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
106 char *resource_name = "System RAM";
108 if (start + size > max_mem_size)
109 return ERR_PTR(-E2BIG);
112 * Request ownership of the new memory range. This might be
113 * a child of an existing resource that was present but
114 * not marked as busy.
116 res = __request_region(&iomem_resource, start, size,
117 resource_name, flags);
120 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
121 start, start + size);
122 return ERR_PTR(-EEXIST);
127 static void release_memory_resource(struct resource *res)
131 release_resource(res);
135 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
136 void get_page_bootmem(unsigned long info, struct page *page,
139 page->freelist = (void *)type;
140 SetPagePrivate(page);
141 set_page_private(page, info);
145 void put_page_bootmem(struct page *page)
149 type = (unsigned long) page->freelist;
150 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
151 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
153 if (page_ref_dec_return(page) == 1) {
154 page->freelist = NULL;
155 ClearPagePrivate(page);
156 set_page_private(page, 0);
157 INIT_LIST_HEAD(&page->lru);
158 free_reserved_page(page);
162 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
163 #ifndef CONFIG_SPARSEMEM_VMEMMAP
164 static void register_page_bootmem_info_section(unsigned long start_pfn)
166 unsigned long mapsize, section_nr, i;
167 struct mem_section *ms;
168 struct page *page, *memmap;
169 struct mem_section_usage *usage;
171 section_nr = pfn_to_section_nr(start_pfn);
172 ms = __nr_to_section(section_nr);
174 /* Get section's memmap address */
175 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
178 * Get page for the memmap's phys address
179 * XXX: need more consideration for sparse_vmemmap...
181 page = virt_to_page(memmap);
182 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
183 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
185 /* remember memmap's page */
186 for (i = 0; i < mapsize; i++, page++)
187 get_page_bootmem(section_nr, page, SECTION_INFO);
190 page = virt_to_page(usage);
192 mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT;
194 for (i = 0; i < mapsize; i++, page++)
195 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
198 #else /* CONFIG_SPARSEMEM_VMEMMAP */
199 static void register_page_bootmem_info_section(unsigned long start_pfn)
201 unsigned long mapsize, section_nr, i;
202 struct mem_section *ms;
203 struct page *page, *memmap;
204 struct mem_section_usage *usage;
206 section_nr = pfn_to_section_nr(start_pfn);
207 ms = __nr_to_section(section_nr);
209 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
211 register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
214 page = virt_to_page(usage);
216 mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT;
218 for (i = 0; i < mapsize; i++, page++)
219 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
221 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
223 void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
225 unsigned long i, pfn, end_pfn, nr_pages;
226 int node = pgdat->node_id;
229 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
230 page = virt_to_page(pgdat);
232 for (i = 0; i < nr_pages; i++, page++)
233 get_page_bootmem(node, page, NODE_INFO);
235 pfn = pgdat->node_start_pfn;
236 end_pfn = pgdat_end_pfn(pgdat);
238 /* register section info */
239 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
241 * Some platforms can assign the same pfn to multiple nodes - on
242 * node0 as well as nodeN. To avoid registering a pfn against
243 * multiple nodes we check that this pfn does not already
244 * reside in some other nodes.
246 if (pfn_valid(pfn) && (early_pfn_to_nid(pfn) == node))
247 register_page_bootmem_info_section(pfn);
250 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
252 static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
256 * Disallow all operations smaller than a sub-section and only
257 * allow operations smaller than a section for
258 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
259 * enforces a larger memory_block_size_bytes() granularity for
260 * memory that will be marked online, so this check should only
261 * fire for direct arch_{add,remove}_memory() users outside of
262 * add_memory_resource().
264 unsigned long min_align;
266 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
267 min_align = PAGES_PER_SUBSECTION;
269 min_align = PAGES_PER_SECTION;
270 if (!IS_ALIGNED(pfn, min_align)
271 || !IS_ALIGNED(nr_pages, min_align)) {
272 WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n",
273 reason, pfn, pfn + nr_pages - 1);
279 static int check_hotplug_memory_addressable(unsigned long pfn,
280 unsigned long nr_pages)
282 const u64 max_addr = PFN_PHYS(pfn + nr_pages) - 1;
284 if (max_addr >> MAX_PHYSMEM_BITS) {
285 const u64 max_allowed = (1ull << (MAX_PHYSMEM_BITS + 1)) - 1;
287 "Hotplugged memory exceeds maximum addressable address, range=%#llx-%#llx, maximum=%#llx\n",
288 (u64)PFN_PHYS(pfn), max_addr, max_allowed);
296 * Reasonably generic function for adding memory. It is
297 * expected that archs that support memory hotplug will
298 * call this function after deciding the zone to which to
301 int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
302 struct mhp_restrictions *restrictions)
305 unsigned long nr, start_sec, end_sec;
306 struct vmem_altmap *altmap = restrictions->altmap;
308 err = check_hotplug_memory_addressable(pfn, nr_pages);
314 * Validate altmap is within bounds of the total request
316 if (altmap->base_pfn != pfn
317 || vmem_altmap_offset(altmap) > nr_pages) {
318 pr_warn_once("memory add fail, invalid altmap\n");
324 err = check_pfn_span(pfn, nr_pages, "add");
328 start_sec = pfn_to_section_nr(pfn);
329 end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
330 for (nr = start_sec; nr <= end_sec; nr++) {
333 pfns = min(nr_pages, PAGES_PER_SECTION
334 - (pfn & ~PAGE_SECTION_MASK));
335 err = sparse_add_section(nid, pfn, pfns, altmap);
342 vmemmap_populate_print_last();
346 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
347 static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
348 unsigned long start_pfn,
349 unsigned long end_pfn)
351 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
352 if (unlikely(!pfn_to_online_page(start_pfn)))
355 if (unlikely(pfn_to_nid(start_pfn) != nid))
358 if (zone != page_zone(pfn_to_page(start_pfn)))
367 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
368 static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
369 unsigned long start_pfn,
370 unsigned long end_pfn)
374 /* pfn is the end pfn of a memory section. */
376 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) {
377 if (unlikely(!pfn_to_online_page(pfn)))
380 if (unlikely(pfn_to_nid(pfn) != nid))
383 if (zone != page_zone(pfn_to_page(pfn)))
392 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
393 unsigned long end_pfn)
395 unsigned long zone_start_pfn = zone->zone_start_pfn;
396 unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
397 unsigned long zone_end_pfn = z;
399 int nid = zone_to_nid(zone);
401 zone_span_writelock(zone);
402 if (zone_start_pfn == start_pfn) {
404 * If the section is smallest section in the zone, it need
405 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
406 * In this case, we find second smallest valid mem_section
407 * for shrinking zone.
409 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
412 zone->zone_start_pfn = pfn;
413 zone->spanned_pages = zone_end_pfn - pfn;
415 zone->zone_start_pfn = 0;
416 zone->spanned_pages = 0;
418 } else if (zone_end_pfn == end_pfn) {
420 * If the section is biggest section in the zone, it need
421 * shrink zone->spanned_pages.
422 * In this case, we find second biggest valid mem_section for
425 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
428 zone->spanned_pages = pfn - zone_start_pfn + 1;
430 zone->zone_start_pfn = 0;
431 zone->spanned_pages = 0;
434 zone_span_writeunlock(zone);
437 static void update_pgdat_span(struct pglist_data *pgdat)
439 unsigned long node_start_pfn = 0, node_end_pfn = 0;
442 for (zone = pgdat->node_zones;
443 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
444 unsigned long zone_end_pfn = zone->zone_start_pfn +
447 /* No need to lock the zones, they can't change. */
448 if (!zone->spanned_pages)
451 node_start_pfn = zone->zone_start_pfn;
452 node_end_pfn = zone_end_pfn;
456 if (zone_end_pfn > node_end_pfn)
457 node_end_pfn = zone_end_pfn;
458 if (zone->zone_start_pfn < node_start_pfn)
459 node_start_pfn = zone->zone_start_pfn;
462 pgdat->node_start_pfn = node_start_pfn;
463 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
466 void __ref remove_pfn_range_from_zone(struct zone *zone,
467 unsigned long start_pfn,
468 unsigned long nr_pages)
470 struct pglist_data *pgdat = zone->zone_pgdat;
473 /* Poison struct pages because they are now uninitialized again. */
474 page_init_poison(pfn_to_page(start_pfn), sizeof(struct page) * nr_pages);
476 #ifdef CONFIG_ZONE_DEVICE
478 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
479 * we will not try to shrink the zones - which is okay as
480 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
482 if (zone_idx(zone) == ZONE_DEVICE)
486 clear_zone_contiguous(zone);
488 pgdat_resize_lock(zone->zone_pgdat, &flags);
489 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
490 update_pgdat_span(pgdat);
491 pgdat_resize_unlock(zone->zone_pgdat, &flags);
493 set_zone_contiguous(zone);
496 static void __remove_section(unsigned long pfn, unsigned long nr_pages,
497 unsigned long map_offset,
498 struct vmem_altmap *altmap)
500 struct mem_section *ms = __nr_to_section(pfn_to_section_nr(pfn));
502 if (WARN_ON_ONCE(!valid_section(ms)))
505 sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap);
509 * __remove_pages() - remove sections of pages
510 * @pfn: starting pageframe (must be aligned to start of a section)
511 * @nr_pages: number of pages to remove (must be multiple of section size)
512 * @altmap: alternative device page map or %NULL if default memmap is used
514 * Generic helper function to remove section mappings and sysfs entries
515 * for the section of the memory we are removing. Caller needs to make
516 * sure that pages are marked reserved and zones are adjust properly by
517 * calling offline_pages().
519 void __remove_pages(unsigned long pfn, unsigned long nr_pages,
520 struct vmem_altmap *altmap)
522 unsigned long map_offset = 0;
523 unsigned long nr, start_sec, end_sec;
525 map_offset = vmem_altmap_offset(altmap);
527 if (check_pfn_span(pfn, nr_pages, "remove"))
530 start_sec = pfn_to_section_nr(pfn);
531 end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
532 for (nr = start_sec; nr <= end_sec; nr++) {
536 pfns = min(nr_pages, PAGES_PER_SECTION
537 - (pfn & ~PAGE_SECTION_MASK));
538 __remove_section(pfn, pfns, map_offset, altmap);
545 int set_online_page_callback(online_page_callback_t callback)
550 mutex_lock(&online_page_callback_lock);
552 if (online_page_callback == generic_online_page) {
553 online_page_callback = callback;
557 mutex_unlock(&online_page_callback_lock);
562 EXPORT_SYMBOL_GPL(set_online_page_callback);
564 int restore_online_page_callback(online_page_callback_t callback)
569 mutex_lock(&online_page_callback_lock);
571 if (online_page_callback == callback) {
572 online_page_callback = generic_online_page;
576 mutex_unlock(&online_page_callback_lock);
581 EXPORT_SYMBOL_GPL(restore_online_page_callback);
583 void generic_online_page(struct page *page, unsigned int order)
585 kernel_map_pages(page, 1 << order, 1);
586 __free_pages_core(page, order);
587 totalram_pages_add(1UL << order);
588 #ifdef CONFIG_HIGHMEM
589 if (PageHighMem(page))
590 totalhigh_pages_add(1UL << order);
593 EXPORT_SYMBOL_GPL(generic_online_page);
595 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
598 const unsigned long end_pfn = start_pfn + nr_pages;
603 * Online the pages. The callback might decide to keep some pages
604 * PG_reserved (to add them to the buddy later), but we still account
605 * them as being online/belonging to this zone ("present").
607 for (pfn = start_pfn; pfn < end_pfn; pfn += 1ul << order) {
608 order = min(MAX_ORDER - 1, get_order(PFN_PHYS(end_pfn - pfn)));
609 /* __free_pages_core() wants pfns to be aligned to the order */
610 if (WARN_ON_ONCE(!IS_ALIGNED(pfn, 1ul << order)))
612 (*online_page_callback)(pfn_to_page(pfn), order);
615 /* mark all involved sections as online */
616 online_mem_sections(start_pfn, end_pfn);
618 *(unsigned long *)arg += nr_pages;
622 /* check which state of node_states will be changed when online memory */
623 static void node_states_check_changes_online(unsigned long nr_pages,
624 struct zone *zone, struct memory_notify *arg)
626 int nid = zone_to_nid(zone);
628 arg->status_change_nid = NUMA_NO_NODE;
629 arg->status_change_nid_normal = NUMA_NO_NODE;
630 arg->status_change_nid_high = NUMA_NO_NODE;
632 if (!node_state(nid, N_MEMORY))
633 arg->status_change_nid = nid;
634 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
635 arg->status_change_nid_normal = nid;
636 #ifdef CONFIG_HIGHMEM
637 if (zone_idx(zone) <= ZONE_HIGHMEM && !node_state(nid, N_HIGH_MEMORY))
638 arg->status_change_nid_high = nid;
642 static void node_states_set_node(int node, struct memory_notify *arg)
644 if (arg->status_change_nid_normal >= 0)
645 node_set_state(node, N_NORMAL_MEMORY);
647 if (arg->status_change_nid_high >= 0)
648 node_set_state(node, N_HIGH_MEMORY);
650 if (arg->status_change_nid >= 0)
651 node_set_state(node, N_MEMORY);
654 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
655 unsigned long nr_pages)
657 unsigned long old_end_pfn = zone_end_pfn(zone);
659 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
660 zone->zone_start_pfn = start_pfn;
662 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
665 static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
666 unsigned long nr_pages)
668 unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
670 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
671 pgdat->node_start_pfn = start_pfn;
673 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
677 * Associate the pfn range with the given zone, initializing the memmaps
678 * and resizing the pgdat/zone data to span the added pages. After this
679 * call, all affected pages are PG_reserved.
681 void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
682 unsigned long nr_pages, struct vmem_altmap *altmap)
684 struct pglist_data *pgdat = zone->zone_pgdat;
685 int nid = pgdat->node_id;
688 clear_zone_contiguous(zone);
690 /* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */
691 pgdat_resize_lock(pgdat, &flags);
692 zone_span_writelock(zone);
693 if (zone_is_empty(zone))
694 init_currently_empty_zone(zone, start_pfn, nr_pages);
695 resize_zone_range(zone, start_pfn, nr_pages);
696 zone_span_writeunlock(zone);
697 resize_pgdat_range(pgdat, start_pfn, nr_pages);
698 pgdat_resize_unlock(pgdat, &flags);
701 * TODO now we have a visible range of pages which are not associated
702 * with their zone properly. Not nice but set_pfnblock_flags_mask
703 * expects the zone spans the pfn range. All the pages in the range
704 * are reserved so nobody should be touching them so we should be safe
706 memmap_init_zone(nr_pages, nid, zone_idx(zone), start_pfn,
707 MEMMAP_HOTPLUG, altmap);
709 set_zone_contiguous(zone);
713 * Returns a default kernel memory zone for the given pfn range.
714 * If no kernel zone covers this pfn range it will automatically go
715 * to the ZONE_NORMAL.
717 static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
718 unsigned long nr_pages)
720 struct pglist_data *pgdat = NODE_DATA(nid);
723 for (zid = 0; zid <= ZONE_NORMAL; zid++) {
724 struct zone *zone = &pgdat->node_zones[zid];
726 if (zone_intersects(zone, start_pfn, nr_pages))
730 return &pgdat->node_zones[ZONE_NORMAL];
733 static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
734 unsigned long nr_pages)
736 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
738 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
739 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
740 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
743 * We inherit the existing zone in a simple case where zones do not
744 * overlap in the given range
746 if (in_kernel ^ in_movable)
747 return (in_kernel) ? kernel_zone : movable_zone;
750 * If the range doesn't belong to any zone or two zones overlap in the
751 * given range then we use movable zone only if movable_node is
752 * enabled because we always online to a kernel zone by default.
754 return movable_node_enabled ? movable_zone : kernel_zone;
757 struct zone * zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
758 unsigned long nr_pages)
760 if (online_type == MMOP_ONLINE_KERNEL)
761 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
763 if (online_type == MMOP_ONLINE_MOVABLE)
764 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
766 return default_zone_for_pfn(nid, start_pfn, nr_pages);
769 int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
770 int online_type, int nid)
773 unsigned long onlined_pages = 0;
775 int need_zonelists_rebuild = 0;
777 struct memory_notify arg;
781 /* associate pfn range with the zone */
782 zone = zone_for_pfn_range(online_type, nid, pfn, nr_pages);
783 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL);
786 arg.nr_pages = nr_pages;
787 node_states_check_changes_online(nr_pages, zone, &arg);
789 ret = memory_notify(MEM_GOING_ONLINE, &arg);
790 ret = notifier_to_errno(ret);
792 goto failed_addition;
795 * If this zone is not populated, then it is not in zonelist.
796 * This means the page allocator ignores this zone.
797 * So, zonelist must be updated after online.
799 if (!populated_zone(zone)) {
800 need_zonelists_rebuild = 1;
801 setup_zone_pageset(zone);
804 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
807 /* not a single memory resource was applicable */
808 if (need_zonelists_rebuild)
809 zone_pcp_reset(zone);
810 goto failed_addition;
813 zone->present_pages += onlined_pages;
815 pgdat_resize_lock(zone->zone_pgdat, &flags);
816 zone->zone_pgdat->node_present_pages += onlined_pages;
817 pgdat_resize_unlock(zone->zone_pgdat, &flags);
821 node_states_set_node(nid, &arg);
822 if (need_zonelists_rebuild)
823 build_all_zonelists(NULL);
825 zone_pcp_update(zone);
827 init_per_zone_wmark_min();
832 vm_total_pages = nr_free_pagecache_pages();
834 writeback_set_ratelimit();
836 memory_notify(MEM_ONLINE, &arg);
841 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
842 (unsigned long long) pfn << PAGE_SHIFT,
843 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
844 memory_notify(MEM_CANCEL_ONLINE, &arg);
845 remove_pfn_range_from_zone(zone, pfn, nr_pages);
849 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
851 static void reset_node_present_pages(pg_data_t *pgdat)
855 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
856 z->present_pages = 0;
858 pgdat->node_present_pages = 0;
861 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
862 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
864 struct pglist_data *pgdat;
865 unsigned long start_pfn = PFN_DOWN(start);
867 pgdat = NODE_DATA(nid);
869 pgdat = arch_alloc_nodedata(nid);
873 pgdat->per_cpu_nodestats =
874 alloc_percpu(struct per_cpu_nodestat);
875 arch_refresh_nodedata(nid, pgdat);
879 * Reset the nr_zones, order and classzone_idx before reuse.
880 * Note that kswapd will init kswapd_classzone_idx properly
881 * when it starts in the near future.
884 pgdat->kswapd_order = 0;
885 pgdat->kswapd_classzone_idx = 0;
886 for_each_online_cpu(cpu) {
887 struct per_cpu_nodestat *p;
889 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
890 memset(p, 0, sizeof(*p));
894 /* we can use NODE_DATA(nid) from here */
896 pgdat->node_id = nid;
897 pgdat->node_start_pfn = start_pfn;
899 /* init node's zones as empty zones, we don't have any present pages.*/
900 free_area_init_core_hotplug(nid);
903 * The node we allocated has no zone fallback lists. For avoiding
904 * to access not-initialized zonelist, build here.
906 build_all_zonelists(pgdat);
909 * When memory is hot-added, all the memory is in offline state. So
910 * clear all zones' present_pages because they will be updated in
911 * online_pages() and offline_pages().
913 reset_node_managed_pages(pgdat);
914 reset_node_present_pages(pgdat);
919 static void rollback_node_hotadd(int nid)
921 pg_data_t *pgdat = NODE_DATA(nid);
923 arch_refresh_nodedata(nid, NULL);
924 free_percpu(pgdat->per_cpu_nodestats);
925 arch_free_nodedata(pgdat);
930 * try_online_node - online a node if offlined
932 * @start: start addr of the node
933 * @set_node_online: Whether we want to online the node
934 * called by cpu_up() to online a node without onlined memory.
937 * 1 -> a new node has been allocated
938 * 0 -> the node is already online
939 * -ENOMEM -> the node could not be allocated
941 static int __try_online_node(int nid, u64 start, bool set_node_online)
946 if (node_online(nid))
949 pgdat = hotadd_new_pgdat(nid, start);
951 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
956 if (set_node_online) {
957 node_set_online(nid);
958 ret = register_one_node(nid);
966 * Users of this function always want to online/register the node
968 int try_online_node(int nid)
973 ret = __try_online_node(nid, 0, true);
978 static int check_hotplug_memory_range(u64 start, u64 size)
980 /* memory range must be block size aligned */
981 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
982 !IS_ALIGNED(size, memory_block_size_bytes())) {
983 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
984 memory_block_size_bytes(), start, size);
991 static int online_memory_block(struct memory_block *mem, void *arg)
993 return device_online(&mem->dev);
997 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
998 * and online/offline operations (triggered e.g. by sysfs).
1000 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1002 int __ref add_memory_resource(int nid, struct resource *res)
1004 struct mhp_restrictions restrictions = {};
1006 bool new_node = false;
1010 size = resource_size(res);
1012 ret = check_hotplug_memory_range(start, size);
1016 mem_hotplug_begin();
1019 * Add new range to memblock so that when hotadd_new_pgdat() is called
1020 * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
1021 * this new range and calculate total pages correctly. The range will
1022 * be removed at hot-remove time.
1024 memblock_add_node(start, size, nid);
1026 ret = __try_online_node(nid, start, false);
1031 /* call arch's memory hotadd */
1032 ret = arch_add_memory(nid, start, size, &restrictions);
1036 /* create memory block devices after memory was added */
1037 ret = create_memory_block_devices(start, size);
1039 arch_remove_memory(nid, start, size, NULL);
1044 /* If sysfs file of new node can't be created, cpu on the node
1045 * can't be hot-added. There is no rollback way now.
1046 * So, check by BUG_ON() to catch it reluctantly..
1047 * We online node here. We can't roll back from here.
1049 node_set_online(nid);
1050 ret = __register_one_node(nid);
1054 /* link memory sections under this node.*/
1055 ret = link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1));
1058 /* create new memmap entry */
1059 firmware_map_add_hotplug(start, start + size, "System RAM");
1061 /* device_online() will take the lock when calling online_pages() */
1064 /* online pages if requested */
1065 if (memhp_auto_online)
1066 walk_memory_blocks(start, size, NULL, online_memory_block);
1070 /* rollback pgdat allocation and others */
1072 rollback_node_hotadd(nid);
1073 memblock_remove(start, size);
1078 /* requires device_hotplug_lock, see add_memory_resource() */
1079 int __ref __add_memory(int nid, u64 start, u64 size)
1081 struct resource *res;
1084 res = register_memory_resource(start, size);
1086 return PTR_ERR(res);
1088 ret = add_memory_resource(nid, res);
1090 release_memory_resource(res);
1094 int add_memory(int nid, u64 start, u64 size)
1098 lock_device_hotplug();
1099 rc = __add_memory(nid, start, size);
1100 unlock_device_hotplug();
1104 EXPORT_SYMBOL_GPL(add_memory);
1106 #ifdef CONFIG_MEMORY_HOTREMOVE
1108 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1109 * set and the size of the free page is given by page_order(). Using this,
1110 * the function determines if the pageblock contains only free pages.
1111 * Due to buddy contraints, a free page at least the size of a pageblock will
1112 * be located at the start of the pageblock
1114 static inline int pageblock_free(struct page *page)
1116 return PageBuddy(page) && page_order(page) >= pageblock_order;
1119 /* Return the pfn of the start of the next active pageblock after a given pfn */
1120 static unsigned long next_active_pageblock(unsigned long pfn)
1122 struct page *page = pfn_to_page(pfn);
1124 /* Ensure the starting page is pageblock-aligned */
1125 BUG_ON(pfn & (pageblock_nr_pages - 1));
1127 /* If the entire pageblock is free, move to the end of free page */
1128 if (pageblock_free(page)) {
1130 /* be careful. we don't have locks, page_order can be changed.*/
1131 order = page_order(page);
1132 if ((order < MAX_ORDER) && (order >= pageblock_order))
1133 return pfn + (1 << order);
1136 return pfn + pageblock_nr_pages;
1139 static bool is_pageblock_removable_nolock(unsigned long pfn)
1141 struct page *page = pfn_to_page(pfn);
1145 * We have to be careful here because we are iterating over memory
1146 * sections which are not zone aware so we might end up outside of
1147 * the zone but still within the section.
1148 * We have to take care about the node as well. If the node is offline
1149 * its NODE_DATA will be NULL - see page_zone.
1151 if (!node_online(page_to_nid(page)))
1154 zone = page_zone(page);
1155 pfn = page_to_pfn(page);
1156 if (!zone_spans_pfn(zone, pfn))
1159 return !has_unmovable_pages(zone, page, MIGRATE_MOVABLE,
1163 /* Checks if this range of memory is likely to be hot-removable. */
1164 bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1166 unsigned long end_pfn, pfn;
1168 end_pfn = min(start_pfn + nr_pages,
1169 zone_end_pfn(page_zone(pfn_to_page(start_pfn))));
1171 /* Check the starting page of each pageblock within the range */
1172 for (pfn = start_pfn; pfn < end_pfn; pfn = next_active_pageblock(pfn)) {
1173 if (!is_pageblock_removable_nolock(pfn))
1178 /* All pageblocks in the memory block are likely to be hot-removable */
1183 * Confirm all pages in a range [start, end) belong to the same zone.
1184 * When true, return its valid [start, end).
1186 int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
1187 unsigned long *valid_start, unsigned long *valid_end)
1189 unsigned long pfn, sec_end_pfn;
1190 unsigned long start, end;
1191 struct zone *zone = NULL;
1194 for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1);
1196 pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) {
1197 /* Make sure the memory section is present first */
1198 if (!present_section_nr(pfn_to_section_nr(pfn)))
1200 for (; pfn < sec_end_pfn && pfn < end_pfn;
1201 pfn += MAX_ORDER_NR_PAGES) {
1203 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1204 while ((i < MAX_ORDER_NR_PAGES) &&
1205 !pfn_valid_within(pfn + i))
1207 if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn)
1209 /* Check if we got outside of the zone */
1210 if (zone && !zone_spans_pfn(zone, pfn + i))
1212 page = pfn_to_page(pfn + i);
1213 if (zone && page_zone(page) != zone)
1217 zone = page_zone(page);
1218 end = pfn + MAX_ORDER_NR_PAGES;
1223 *valid_start = start;
1224 *valid_end = min(end, end_pfn);
1232 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1233 * non-lru movable pages and hugepages). We scan pfn because it's much
1234 * easier than scanning over linked list. This function returns the pfn
1235 * of the first found movable page if it's found, otherwise 0.
1237 static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1241 for (pfn = start; pfn < end; pfn++) {
1242 struct page *page, *head;
1245 if (!pfn_valid(pfn))
1247 page = pfn_to_page(pfn);
1250 if (__PageMovable(page))
1253 if (!PageHuge(page))
1255 head = compound_head(page);
1256 if (page_huge_active(head))
1258 skip = compound_nr(head) - (page - head);
1264 static struct page *new_node_page(struct page *page, unsigned long private)
1266 int nid = page_to_nid(page);
1267 nodemask_t nmask = node_states[N_MEMORY];
1270 * try to allocate from a different node but reuse this node if there
1271 * are no other online nodes to be used (e.g. we are offlining a part
1272 * of the only existing node)
1274 node_clear(nid, nmask);
1275 if (nodes_empty(nmask))
1276 node_set(nid, nmask);
1278 return new_page_nodemask(page, nid, &nmask);
1282 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1289 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1290 if (!pfn_valid(pfn))
1292 page = pfn_to_page(pfn);
1294 if (PageHuge(page)) {
1295 struct page *head = compound_head(page);
1296 pfn = page_to_pfn(head) + compound_nr(head) - 1;
1297 isolate_huge_page(head, &source);
1299 } else if (PageTransHuge(page))
1300 pfn = page_to_pfn(compound_head(page))
1301 + hpage_nr_pages(page) - 1;
1304 * HWPoison pages have elevated reference counts so the migration would
1305 * fail on them. It also doesn't make any sense to migrate them in the
1306 * first place. Still try to unmap such a page in case it is still mapped
1307 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1308 * the unmap as the catch all safety net).
1310 if (PageHWPoison(page)) {
1311 if (WARN_ON(PageLRU(page)))
1312 isolate_lru_page(page);
1313 if (page_mapped(page))
1314 try_to_unmap(page, TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS);
1318 if (!get_page_unless_zero(page))
1321 * We can skip free pages. And we can deal with pages on
1322 * LRU and non-lru movable pages.
1325 ret = isolate_lru_page(page);
1327 ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
1328 if (!ret) { /* Success */
1329 list_add_tail(&page->lru, &source);
1330 if (!__PageMovable(page))
1331 inc_node_page_state(page, NR_ISOLATED_ANON +
1332 page_is_file_cache(page));
1335 pr_warn("failed to isolate pfn %lx\n", pfn);
1336 dump_page(page, "isolation failed");
1340 if (!list_empty(&source)) {
1341 /* Allocate a new page from the nearest neighbor node */
1342 ret = migrate_pages(&source, new_node_page, NULL, 0,
1343 MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1345 list_for_each_entry(page, &source, lru) {
1346 pr_warn("migrating pfn %lx failed ret:%d ",
1347 page_to_pfn(page), ret);
1348 dump_page(page, "migration failure");
1350 putback_movable_pages(&source);
1357 /* Mark all sections offline and remove all free pages from the buddy. */
1359 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1362 unsigned long *offlined_pages = (unsigned long *)data;
1364 *offlined_pages += __offline_isolated_pages(start, start + nr_pages);
1369 * Check all pages in range, recoreded as memory resource, are isolated.
1372 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1375 return test_pages_isolated(start_pfn, start_pfn + nr_pages,
1379 static int __init cmdline_parse_movable_node(char *p)
1381 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1382 movable_node_enabled = true;
1384 pr_warn("movable_node parameter depends on CONFIG_HAVE_MEMBLOCK_NODE_MAP to work properly\n");
1388 early_param("movable_node", cmdline_parse_movable_node);
1390 /* check which state of node_states will be changed when offline memory */
1391 static void node_states_check_changes_offline(unsigned long nr_pages,
1392 struct zone *zone, struct memory_notify *arg)
1394 struct pglist_data *pgdat = zone->zone_pgdat;
1395 unsigned long present_pages = 0;
1398 arg->status_change_nid = NUMA_NO_NODE;
1399 arg->status_change_nid_normal = NUMA_NO_NODE;
1400 arg->status_change_nid_high = NUMA_NO_NODE;
1403 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1404 * If the memory to be offline is within the range
1405 * [0..ZONE_NORMAL], and it is the last present memory there,
1406 * the zones in that range will become empty after the offlining,
1407 * thus we can determine that we need to clear the node from
1408 * node_states[N_NORMAL_MEMORY].
1410 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1411 present_pages += pgdat->node_zones[zt].present_pages;
1412 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
1413 arg->status_change_nid_normal = zone_to_nid(zone);
1415 #ifdef CONFIG_HIGHMEM
1417 * node_states[N_HIGH_MEMORY] contains nodes which
1418 * have normal memory or high memory.
1419 * Here we add the present_pages belonging to ZONE_HIGHMEM.
1420 * If the zone is within the range of [0..ZONE_HIGHMEM), and
1421 * we determine that the zones in that range become empty,
1422 * we need to clear the node for N_HIGH_MEMORY.
1424 present_pages += pgdat->node_zones[ZONE_HIGHMEM].present_pages;
1425 if (zone_idx(zone) <= ZONE_HIGHMEM && nr_pages >= present_pages)
1426 arg->status_change_nid_high = zone_to_nid(zone);
1430 * We have accounted the pages from [0..ZONE_NORMAL), and
1431 * in case of CONFIG_HIGHMEM the pages from ZONE_HIGHMEM
1433 * Here we count the possible pages from ZONE_MOVABLE.
1434 * If after having accounted all the pages, we see that the nr_pages
1435 * to be offlined is over or equal to the accounted pages,
1436 * we know that the node will become empty, and so, we can clear
1437 * it for N_MEMORY as well.
1439 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
1441 if (nr_pages >= present_pages)
1442 arg->status_change_nid = zone_to_nid(zone);
1445 static void node_states_clear_node(int node, struct memory_notify *arg)
1447 if (arg->status_change_nid_normal >= 0)
1448 node_clear_state(node, N_NORMAL_MEMORY);
1450 if (arg->status_change_nid_high >= 0)
1451 node_clear_state(node, N_HIGH_MEMORY);
1453 if (arg->status_change_nid >= 0)
1454 node_clear_state(node, N_MEMORY);
1457 static int count_system_ram_pages_cb(unsigned long start_pfn,
1458 unsigned long nr_pages, void *data)
1460 unsigned long *nr_system_ram_pages = data;
1462 *nr_system_ram_pages += nr_pages;
1466 static int __ref __offline_pages(unsigned long start_pfn,
1467 unsigned long end_pfn)
1469 unsigned long pfn, nr_pages = 0;
1470 unsigned long offlined_pages = 0;
1471 int ret, node, nr_isolate_pageblock;
1472 unsigned long flags;
1473 unsigned long valid_start, valid_end;
1475 struct memory_notify arg;
1478 mem_hotplug_begin();
1481 * Don't allow to offline memory blocks that contain holes.
1482 * Consequently, memory blocks with holes can never get onlined
1483 * via the hotplug path - online_pages() - as hotplugged memory has
1484 * no holes. This way, we e.g., don't have to worry about marking
1485 * memory holes PG_reserved, don't need pfn_valid() checks, and can
1486 * avoid using walk_system_ram_range() later.
1488 walk_system_ram_range(start_pfn, end_pfn - start_pfn, &nr_pages,
1489 count_system_ram_pages_cb);
1490 if (nr_pages != end_pfn - start_pfn) {
1492 reason = "memory holes";
1493 goto failed_removal;
1496 /* This makes hotplug much easier...and readable.
1497 we assume this for now. .*/
1498 if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start,
1501 reason = "multizone range";
1502 goto failed_removal;
1505 zone = page_zone(pfn_to_page(valid_start));
1506 node = zone_to_nid(zone);
1508 /* set above range as isolated */
1509 ret = start_isolate_page_range(start_pfn, end_pfn,
1511 MEMORY_OFFLINE | 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));
1742 * All memory blocks must be offlined before removing memory. Check
1743 * whether all memory blocks in question are offline and return error
1744 * if this is not the case.
1746 rc = walk_memory_blocks(start, size, NULL, check_memblock_offlined_cb);
1750 /* remove memmap entry */
1751 firmware_map_remove(start, start + size, "System RAM");
1754 * Memory block device removal under the device_hotplug_lock is
1755 * a barrier against racing online attempts.
1757 remove_memory_block_devices(start, size);
1759 mem_hotplug_begin();
1761 arch_remove_memory(nid, start, size, NULL);
1762 memblock_free(start, size);
1763 memblock_remove(start, size);
1764 __release_memory_resource(start, size);
1766 try_offline_node(nid);
1776 * @start: physical address of the region to remove
1777 * @size: size of the region to remove
1779 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1780 * and online/offline operations before this call, as required by
1781 * try_offline_node().
1783 void __remove_memory(int nid, u64 start, u64 size)
1787 * trigger BUG() if some memory is not offlined prior to calling this
1790 if (try_remove_memory(nid, start, size))
1795 * Remove memory if every memory block is offline, otherwise return -EBUSY is
1796 * some memory is not offline
1798 int remove_memory(int nid, u64 start, u64 size)
1802 lock_device_hotplug();
1803 rc = try_remove_memory(nid, start, size);
1804 unlock_device_hotplug();
1808 EXPORT_SYMBOL_GPL(remove_memory);
1809 #endif /* CONFIG_MEMORY_HOTREMOVE */