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 } else if (zone_end_pfn == end_pfn) {
417 * If the section is biggest section in the zone, it need
418 * shrink zone->spanned_pages.
419 * In this case, we find second biggest valid mem_section for
422 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
425 zone->spanned_pages = pfn - zone_start_pfn + 1;
429 * The section is not biggest or smallest mem_section in the zone, it
430 * only creates a hole in the zone. So in this case, we need not
431 * change the zone. But perhaps, the zone has only hole data. Thus
432 * it check the zone has only hole or not.
434 pfn = zone_start_pfn;
435 for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUBSECTION) {
436 if (unlikely(!pfn_to_online_page(pfn)))
439 if (page_zone(pfn_to_page(pfn)) != zone)
442 /* Skip range to be removed */
443 if (pfn >= start_pfn && pfn < end_pfn)
446 /* If we find valid section, we have nothing to do */
447 zone_span_writeunlock(zone);
451 /* The zone has no valid section */
452 zone->zone_start_pfn = 0;
453 zone->spanned_pages = 0;
454 zone_span_writeunlock(zone);
457 static void update_pgdat_span(struct pglist_data *pgdat)
459 unsigned long node_start_pfn = 0, node_end_pfn = 0;
462 for (zone = pgdat->node_zones;
463 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
464 unsigned long zone_end_pfn = zone->zone_start_pfn +
467 /* No need to lock the zones, they can't change. */
468 if (!zone->spanned_pages)
471 node_start_pfn = zone->zone_start_pfn;
472 node_end_pfn = zone_end_pfn;
476 if (zone_end_pfn > node_end_pfn)
477 node_end_pfn = zone_end_pfn;
478 if (zone->zone_start_pfn < node_start_pfn)
479 node_start_pfn = zone->zone_start_pfn;
482 pgdat->node_start_pfn = node_start_pfn;
483 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
486 void __ref remove_pfn_range_from_zone(struct zone *zone,
487 unsigned long start_pfn,
488 unsigned long nr_pages)
490 struct pglist_data *pgdat = zone->zone_pgdat;
493 /* Poison struct pages because they are now uninitialized again. */
494 page_init_poison(pfn_to_page(start_pfn), sizeof(struct page) * nr_pages);
496 #ifdef CONFIG_ZONE_DEVICE
498 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
499 * we will not try to shrink the zones - which is okay as
500 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
502 if (zone_idx(zone) == ZONE_DEVICE)
506 clear_zone_contiguous(zone);
508 pgdat_resize_lock(zone->zone_pgdat, &flags);
509 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
510 update_pgdat_span(pgdat);
511 pgdat_resize_unlock(zone->zone_pgdat, &flags);
513 set_zone_contiguous(zone);
516 static void __remove_section(unsigned long pfn, unsigned long nr_pages,
517 unsigned long map_offset,
518 struct vmem_altmap *altmap)
520 struct mem_section *ms = __nr_to_section(pfn_to_section_nr(pfn));
522 if (WARN_ON_ONCE(!valid_section(ms)))
525 sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap);
529 * __remove_pages() - remove sections of pages
530 * @pfn: starting pageframe (must be aligned to start of a section)
531 * @nr_pages: number of pages to remove (must be multiple of section size)
532 * @altmap: alternative device page map or %NULL if default memmap is used
534 * Generic helper function to remove section mappings and sysfs entries
535 * for the section of the memory we are removing. Caller needs to make
536 * sure that pages are marked reserved and zones are adjust properly by
537 * calling offline_pages().
539 void __remove_pages(unsigned long pfn, unsigned long nr_pages,
540 struct vmem_altmap *altmap)
542 unsigned long map_offset = 0;
543 unsigned long nr, start_sec, end_sec;
545 map_offset = vmem_altmap_offset(altmap);
547 if (check_pfn_span(pfn, nr_pages, "remove"))
550 start_sec = pfn_to_section_nr(pfn);
551 end_sec = pfn_to_section_nr(pfn + nr_pages - 1);
552 for (nr = start_sec; nr <= end_sec; nr++) {
556 pfns = min(nr_pages, PAGES_PER_SECTION
557 - (pfn & ~PAGE_SECTION_MASK));
558 __remove_section(pfn, pfns, map_offset, altmap);
565 int set_online_page_callback(online_page_callback_t callback)
570 mutex_lock(&online_page_callback_lock);
572 if (online_page_callback == generic_online_page) {
573 online_page_callback = callback;
577 mutex_unlock(&online_page_callback_lock);
582 EXPORT_SYMBOL_GPL(set_online_page_callback);
584 int restore_online_page_callback(online_page_callback_t callback)
589 mutex_lock(&online_page_callback_lock);
591 if (online_page_callback == callback) {
592 online_page_callback = generic_online_page;
596 mutex_unlock(&online_page_callback_lock);
601 EXPORT_SYMBOL_GPL(restore_online_page_callback);
603 void generic_online_page(struct page *page, unsigned int order)
605 kernel_map_pages(page, 1 << order, 1);
606 __free_pages_core(page, order);
607 totalram_pages_add(1UL << order);
608 #ifdef CONFIG_HIGHMEM
609 if (PageHighMem(page))
610 totalhigh_pages_add(1UL << order);
613 EXPORT_SYMBOL_GPL(generic_online_page);
615 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
618 const unsigned long end_pfn = start_pfn + nr_pages;
623 * Online the pages. The callback might decide to keep some pages
624 * PG_reserved (to add them to the buddy later), but we still account
625 * them as being online/belonging to this zone ("present").
627 for (pfn = start_pfn; pfn < end_pfn; pfn += 1ul << order) {
628 order = min(MAX_ORDER - 1, get_order(PFN_PHYS(end_pfn - pfn)));
629 /* __free_pages_core() wants pfns to be aligned to the order */
630 if (WARN_ON_ONCE(!IS_ALIGNED(pfn, 1ul << order)))
632 (*online_page_callback)(pfn_to_page(pfn), order);
635 /* mark all involved sections as online */
636 online_mem_sections(start_pfn, end_pfn);
638 *(unsigned long *)arg += nr_pages;
642 /* check which state of node_states will be changed when online memory */
643 static void node_states_check_changes_online(unsigned long nr_pages,
644 struct zone *zone, struct memory_notify *arg)
646 int nid = zone_to_nid(zone);
648 arg->status_change_nid = NUMA_NO_NODE;
649 arg->status_change_nid_normal = NUMA_NO_NODE;
650 arg->status_change_nid_high = NUMA_NO_NODE;
652 if (!node_state(nid, N_MEMORY))
653 arg->status_change_nid = nid;
654 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
655 arg->status_change_nid_normal = nid;
656 #ifdef CONFIG_HIGHMEM
657 if (zone_idx(zone) <= ZONE_HIGHMEM && !node_state(nid, N_HIGH_MEMORY))
658 arg->status_change_nid_high = nid;
662 static void node_states_set_node(int node, struct memory_notify *arg)
664 if (arg->status_change_nid_normal >= 0)
665 node_set_state(node, N_NORMAL_MEMORY);
667 if (arg->status_change_nid_high >= 0)
668 node_set_state(node, N_HIGH_MEMORY);
670 if (arg->status_change_nid >= 0)
671 node_set_state(node, N_MEMORY);
674 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
675 unsigned long nr_pages)
677 unsigned long old_end_pfn = zone_end_pfn(zone);
679 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
680 zone->zone_start_pfn = start_pfn;
682 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
685 static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
686 unsigned long nr_pages)
688 unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
690 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
691 pgdat->node_start_pfn = start_pfn;
693 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
697 * Associate the pfn range with the given zone, initializing the memmaps
698 * and resizing the pgdat/zone data to span the added pages. After this
699 * call, all affected pages are PG_reserved.
701 void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
702 unsigned long nr_pages, struct vmem_altmap *altmap)
704 struct pglist_data *pgdat = zone->zone_pgdat;
705 int nid = pgdat->node_id;
708 clear_zone_contiguous(zone);
710 /* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */
711 pgdat_resize_lock(pgdat, &flags);
712 zone_span_writelock(zone);
713 if (zone_is_empty(zone))
714 init_currently_empty_zone(zone, start_pfn, nr_pages);
715 resize_zone_range(zone, start_pfn, nr_pages);
716 zone_span_writeunlock(zone);
717 resize_pgdat_range(pgdat, start_pfn, nr_pages);
718 pgdat_resize_unlock(pgdat, &flags);
721 * TODO now we have a visible range of pages which are not associated
722 * with their zone properly. Not nice but set_pfnblock_flags_mask
723 * expects the zone spans the pfn range. All the pages in the range
724 * are reserved so nobody should be touching them so we should be safe
726 memmap_init_zone(nr_pages, nid, zone_idx(zone), start_pfn,
727 MEMMAP_HOTPLUG, altmap);
729 set_zone_contiguous(zone);
733 * Returns a default kernel memory zone for the given pfn range.
734 * If no kernel zone covers this pfn range it will automatically go
735 * to the ZONE_NORMAL.
737 static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
738 unsigned long nr_pages)
740 struct pglist_data *pgdat = NODE_DATA(nid);
743 for (zid = 0; zid <= ZONE_NORMAL; zid++) {
744 struct zone *zone = &pgdat->node_zones[zid];
746 if (zone_intersects(zone, start_pfn, nr_pages))
750 return &pgdat->node_zones[ZONE_NORMAL];
753 static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
754 unsigned long nr_pages)
756 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
758 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
759 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
760 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
763 * We inherit the existing zone in a simple case where zones do not
764 * overlap in the given range
766 if (in_kernel ^ in_movable)
767 return (in_kernel) ? kernel_zone : movable_zone;
770 * If the range doesn't belong to any zone or two zones overlap in the
771 * given range then we use movable zone only if movable_node is
772 * enabled because we always online to a kernel zone by default.
774 return movable_node_enabled ? movable_zone : kernel_zone;
777 struct zone * zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
778 unsigned long nr_pages)
780 if (online_type == MMOP_ONLINE_KERNEL)
781 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
783 if (online_type == MMOP_ONLINE_MOVABLE)
784 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
786 return default_zone_for_pfn(nid, start_pfn, nr_pages);
789 int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
790 int online_type, int nid)
793 unsigned long onlined_pages = 0;
795 int need_zonelists_rebuild = 0;
797 struct memory_notify arg;
801 /* associate pfn range with the zone */
802 zone = zone_for_pfn_range(online_type, nid, pfn, nr_pages);
803 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL);
806 arg.nr_pages = nr_pages;
807 node_states_check_changes_online(nr_pages, zone, &arg);
809 ret = memory_notify(MEM_GOING_ONLINE, &arg);
810 ret = notifier_to_errno(ret);
812 goto failed_addition;
815 * If this zone is not populated, then it is not in zonelist.
816 * This means the page allocator ignores this zone.
817 * So, zonelist must be updated after online.
819 if (!populated_zone(zone)) {
820 need_zonelists_rebuild = 1;
821 setup_zone_pageset(zone);
824 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
827 /* not a single memory resource was applicable */
828 if (need_zonelists_rebuild)
829 zone_pcp_reset(zone);
830 goto failed_addition;
833 zone->present_pages += onlined_pages;
835 pgdat_resize_lock(zone->zone_pgdat, &flags);
836 zone->zone_pgdat->node_present_pages += onlined_pages;
837 pgdat_resize_unlock(zone->zone_pgdat, &flags);
841 node_states_set_node(nid, &arg);
842 if (need_zonelists_rebuild)
843 build_all_zonelists(NULL);
845 zone_pcp_update(zone);
847 init_per_zone_wmark_min();
852 vm_total_pages = nr_free_pagecache_pages();
854 writeback_set_ratelimit();
856 memory_notify(MEM_ONLINE, &arg);
861 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
862 (unsigned long long) pfn << PAGE_SHIFT,
863 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
864 memory_notify(MEM_CANCEL_ONLINE, &arg);
865 remove_pfn_range_from_zone(zone, pfn, nr_pages);
869 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
871 static void reset_node_present_pages(pg_data_t *pgdat)
875 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
876 z->present_pages = 0;
878 pgdat->node_present_pages = 0;
881 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
882 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
884 struct pglist_data *pgdat;
885 unsigned long start_pfn = PFN_DOWN(start);
887 pgdat = NODE_DATA(nid);
889 pgdat = arch_alloc_nodedata(nid);
893 pgdat->per_cpu_nodestats =
894 alloc_percpu(struct per_cpu_nodestat);
895 arch_refresh_nodedata(nid, pgdat);
899 * Reset the nr_zones, order and classzone_idx before reuse.
900 * Note that kswapd will init kswapd_classzone_idx properly
901 * when it starts in the near future.
904 pgdat->kswapd_order = 0;
905 pgdat->kswapd_classzone_idx = 0;
906 for_each_online_cpu(cpu) {
907 struct per_cpu_nodestat *p;
909 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
910 memset(p, 0, sizeof(*p));
914 /* we can use NODE_DATA(nid) from here */
916 pgdat->node_id = nid;
917 pgdat->node_start_pfn = start_pfn;
919 /* init node's zones as empty zones, we don't have any present pages.*/
920 free_area_init_core_hotplug(nid);
923 * The node we allocated has no zone fallback lists. For avoiding
924 * to access not-initialized zonelist, build here.
926 build_all_zonelists(pgdat);
929 * When memory is hot-added, all the memory is in offline state. So
930 * clear all zones' present_pages because they will be updated in
931 * online_pages() and offline_pages().
933 reset_node_managed_pages(pgdat);
934 reset_node_present_pages(pgdat);
939 static void rollback_node_hotadd(int nid)
941 pg_data_t *pgdat = NODE_DATA(nid);
943 arch_refresh_nodedata(nid, NULL);
944 free_percpu(pgdat->per_cpu_nodestats);
945 arch_free_nodedata(pgdat);
950 * try_online_node - online a node if offlined
952 * @start: start addr of the node
953 * @set_node_online: Whether we want to online the node
954 * called by cpu_up() to online a node without onlined memory.
957 * 1 -> a new node has been allocated
958 * 0 -> the node is already online
959 * -ENOMEM -> the node could not be allocated
961 static int __try_online_node(int nid, u64 start, bool set_node_online)
966 if (node_online(nid))
969 pgdat = hotadd_new_pgdat(nid, start);
971 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
976 if (set_node_online) {
977 node_set_online(nid);
978 ret = register_one_node(nid);
986 * Users of this function always want to online/register the node
988 int try_online_node(int nid)
993 ret = __try_online_node(nid, 0, true);
998 static int check_hotplug_memory_range(u64 start, u64 size)
1000 /* memory range must be block size aligned */
1001 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
1002 !IS_ALIGNED(size, memory_block_size_bytes())) {
1003 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1004 memory_block_size_bytes(), start, size);
1011 static int online_memory_block(struct memory_block *mem, void *arg)
1013 return device_online(&mem->dev);
1017 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1018 * and online/offline operations (triggered e.g. by sysfs).
1020 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1022 int __ref add_memory_resource(int nid, struct resource *res)
1024 struct mhp_restrictions restrictions = {};
1026 bool new_node = false;
1030 size = resource_size(res);
1032 ret = check_hotplug_memory_range(start, size);
1036 mem_hotplug_begin();
1039 * Add new range to memblock so that when hotadd_new_pgdat() is called
1040 * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
1041 * this new range and calculate total pages correctly. The range will
1042 * be removed at hot-remove time.
1044 memblock_add_node(start, size, nid);
1046 ret = __try_online_node(nid, start, false);
1051 /* call arch's memory hotadd */
1052 ret = arch_add_memory(nid, start, size, &restrictions);
1056 /* create memory block devices after memory was added */
1057 ret = create_memory_block_devices(start, size);
1059 arch_remove_memory(nid, start, size, NULL);
1064 /* If sysfs file of new node can't be created, cpu on the node
1065 * can't be hot-added. There is no rollback way now.
1066 * So, check by BUG_ON() to catch it reluctantly..
1067 * We online node here. We can't roll back from here.
1069 node_set_online(nid);
1070 ret = __register_one_node(nid);
1074 /* link memory sections under this node.*/
1075 ret = link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1));
1078 /* create new memmap entry */
1079 firmware_map_add_hotplug(start, start + size, "System RAM");
1081 /* device_online() will take the lock when calling online_pages() */
1084 /* online pages if requested */
1085 if (memhp_auto_online)
1086 walk_memory_blocks(start, size, NULL, online_memory_block);
1090 /* rollback pgdat allocation and others */
1092 rollback_node_hotadd(nid);
1093 memblock_remove(start, size);
1098 /* requires device_hotplug_lock, see add_memory_resource() */
1099 int __ref __add_memory(int nid, u64 start, u64 size)
1101 struct resource *res;
1104 res = register_memory_resource(start, size);
1106 return PTR_ERR(res);
1108 ret = add_memory_resource(nid, res);
1110 release_memory_resource(res);
1114 int add_memory(int nid, u64 start, u64 size)
1118 lock_device_hotplug();
1119 rc = __add_memory(nid, start, size);
1120 unlock_device_hotplug();
1124 EXPORT_SYMBOL_GPL(add_memory);
1126 #ifdef CONFIG_MEMORY_HOTREMOVE
1128 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1129 * set and the size of the free page is given by page_order(). Using this,
1130 * the function determines if the pageblock contains only free pages.
1131 * Due to buddy contraints, a free page at least the size of a pageblock will
1132 * be located at the start of the pageblock
1134 static inline int pageblock_free(struct page *page)
1136 return PageBuddy(page) && page_order(page) >= pageblock_order;
1139 /* Return the pfn of the start of the next active pageblock after a given pfn */
1140 static unsigned long next_active_pageblock(unsigned long pfn)
1142 struct page *page = pfn_to_page(pfn);
1144 /* Ensure the starting page is pageblock-aligned */
1145 BUG_ON(pfn & (pageblock_nr_pages - 1));
1147 /* If the entire pageblock is free, move to the end of free page */
1148 if (pageblock_free(page)) {
1150 /* be careful. we don't have locks, page_order can be changed.*/
1151 order = page_order(page);
1152 if ((order < MAX_ORDER) && (order >= pageblock_order))
1153 return pfn + (1 << order);
1156 return pfn + pageblock_nr_pages;
1159 static bool is_pageblock_removable_nolock(unsigned long pfn)
1161 struct page *page = pfn_to_page(pfn);
1165 * We have to be careful here because we are iterating over memory
1166 * sections which are not zone aware so we might end up outside of
1167 * the zone but still within the section.
1168 * We have to take care about the node as well. If the node is offline
1169 * its NODE_DATA will be NULL - see page_zone.
1171 if (!node_online(page_to_nid(page)))
1174 zone = page_zone(page);
1175 pfn = page_to_pfn(page);
1176 if (!zone_spans_pfn(zone, pfn))
1179 return !has_unmovable_pages(zone, page, MIGRATE_MOVABLE,
1183 /* Checks if this range of memory is likely to be hot-removable. */
1184 bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1186 unsigned long end_pfn, pfn;
1188 end_pfn = min(start_pfn + nr_pages,
1189 zone_end_pfn(page_zone(pfn_to_page(start_pfn))));
1191 /* Check the starting page of each pageblock within the range */
1192 for (pfn = start_pfn; pfn < end_pfn; pfn = next_active_pageblock(pfn)) {
1193 if (!is_pageblock_removable_nolock(pfn))
1198 /* All pageblocks in the memory block are likely to be hot-removable */
1203 * Confirm all pages in a range [start, end) belong to the same zone.
1204 * When true, return its valid [start, end).
1206 int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
1207 unsigned long *valid_start, unsigned long *valid_end)
1209 unsigned long pfn, sec_end_pfn;
1210 unsigned long start, end;
1211 struct zone *zone = NULL;
1214 for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1);
1216 pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) {
1217 /* Make sure the memory section is present first */
1218 if (!present_section_nr(pfn_to_section_nr(pfn)))
1220 for (; pfn < sec_end_pfn && pfn < end_pfn;
1221 pfn += MAX_ORDER_NR_PAGES) {
1223 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1224 while ((i < MAX_ORDER_NR_PAGES) &&
1225 !pfn_valid_within(pfn + i))
1227 if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn)
1229 /* Check if we got outside of the zone */
1230 if (zone && !zone_spans_pfn(zone, pfn + i))
1232 page = pfn_to_page(pfn + i);
1233 if (zone && page_zone(page) != zone)
1237 zone = page_zone(page);
1238 end = pfn + MAX_ORDER_NR_PAGES;
1243 *valid_start = start;
1244 *valid_end = min(end, end_pfn);
1252 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1253 * non-lru movable pages and hugepages). We scan pfn because it's much
1254 * easier than scanning over linked list. This function returns the pfn
1255 * of the first found movable page if it's found, otherwise 0.
1257 static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1261 for (pfn = start; pfn < end; pfn++) {
1262 struct page *page, *head;
1265 if (!pfn_valid(pfn))
1267 page = pfn_to_page(pfn);
1270 if (__PageMovable(page))
1273 if (!PageHuge(page))
1275 head = compound_head(page);
1276 if (page_huge_active(head))
1278 skip = compound_nr(head) - (page - head);
1284 static struct page *new_node_page(struct page *page, unsigned long private)
1286 int nid = page_to_nid(page);
1287 nodemask_t nmask = node_states[N_MEMORY];
1290 * try to allocate from a different node but reuse this node if there
1291 * are no other online nodes to be used (e.g. we are offlining a part
1292 * of the only existing node)
1294 node_clear(nid, nmask);
1295 if (nodes_empty(nmask))
1296 node_set(nid, nmask);
1298 return new_page_nodemask(page, nid, &nmask);
1302 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1309 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1310 if (!pfn_valid(pfn))
1312 page = pfn_to_page(pfn);
1314 if (PageHuge(page)) {
1315 struct page *head = compound_head(page);
1316 pfn = page_to_pfn(head) + compound_nr(head) - 1;
1317 isolate_huge_page(head, &source);
1319 } else if (PageTransHuge(page))
1320 pfn = page_to_pfn(compound_head(page))
1321 + hpage_nr_pages(page) - 1;
1324 * HWPoison pages have elevated reference counts so the migration would
1325 * fail on them. It also doesn't make any sense to migrate them in the
1326 * first place. Still try to unmap such a page in case it is still mapped
1327 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1328 * the unmap as the catch all safety net).
1330 if (PageHWPoison(page)) {
1331 if (WARN_ON(PageLRU(page)))
1332 isolate_lru_page(page);
1333 if (page_mapped(page))
1334 try_to_unmap(page, TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS);
1338 if (!get_page_unless_zero(page))
1341 * We can skip free pages. And we can deal with pages on
1342 * LRU and non-lru movable pages.
1345 ret = isolate_lru_page(page);
1347 ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
1348 if (!ret) { /* Success */
1349 list_add_tail(&page->lru, &source);
1350 if (!__PageMovable(page))
1351 inc_node_page_state(page, NR_ISOLATED_ANON +
1352 page_is_file_cache(page));
1355 pr_warn("failed to isolate pfn %lx\n", pfn);
1356 dump_page(page, "isolation failed");
1360 if (!list_empty(&source)) {
1361 /* Allocate a new page from the nearest neighbor node */
1362 ret = migrate_pages(&source, new_node_page, NULL, 0,
1363 MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1365 list_for_each_entry(page, &source, lru) {
1366 pr_warn("migrating pfn %lx failed ret:%d ",
1367 page_to_pfn(page), ret);
1368 dump_page(page, "migration failure");
1370 putback_movable_pages(&source);
1377 /* Mark all sections offline and remove all free pages from the buddy. */
1379 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1382 unsigned long *offlined_pages = (unsigned long *)data;
1384 *offlined_pages += __offline_isolated_pages(start, start + nr_pages);
1389 * Check all pages in range, recoreded as memory resource, are isolated.
1392 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1395 return test_pages_isolated(start_pfn, start_pfn + nr_pages,
1399 static int __init cmdline_parse_movable_node(char *p)
1401 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1402 movable_node_enabled = true;
1404 pr_warn("movable_node parameter depends on CONFIG_HAVE_MEMBLOCK_NODE_MAP to work properly\n");
1408 early_param("movable_node", cmdline_parse_movable_node);
1410 /* check which state of node_states will be changed when offline memory */
1411 static void node_states_check_changes_offline(unsigned long nr_pages,
1412 struct zone *zone, struct memory_notify *arg)
1414 struct pglist_data *pgdat = zone->zone_pgdat;
1415 unsigned long present_pages = 0;
1418 arg->status_change_nid = NUMA_NO_NODE;
1419 arg->status_change_nid_normal = NUMA_NO_NODE;
1420 arg->status_change_nid_high = NUMA_NO_NODE;
1423 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1424 * If the memory to be offline is within the range
1425 * [0..ZONE_NORMAL], and it is the last present memory there,
1426 * the zones in that range will become empty after the offlining,
1427 * thus we can determine that we need to clear the node from
1428 * node_states[N_NORMAL_MEMORY].
1430 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1431 present_pages += pgdat->node_zones[zt].present_pages;
1432 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
1433 arg->status_change_nid_normal = zone_to_nid(zone);
1435 #ifdef CONFIG_HIGHMEM
1437 * node_states[N_HIGH_MEMORY] contains nodes which
1438 * have normal memory or high memory.
1439 * Here we add the present_pages belonging to ZONE_HIGHMEM.
1440 * If the zone is within the range of [0..ZONE_HIGHMEM), and
1441 * we determine that the zones in that range become empty,
1442 * we need to clear the node for N_HIGH_MEMORY.
1444 present_pages += pgdat->node_zones[ZONE_HIGHMEM].present_pages;
1445 if (zone_idx(zone) <= ZONE_HIGHMEM && nr_pages >= present_pages)
1446 arg->status_change_nid_high = zone_to_nid(zone);
1450 * We have accounted the pages from [0..ZONE_NORMAL), and
1451 * in case of CONFIG_HIGHMEM the pages from ZONE_HIGHMEM
1453 * Here we count the possible pages from ZONE_MOVABLE.
1454 * If after having accounted all the pages, we see that the nr_pages
1455 * to be offlined is over or equal to the accounted pages,
1456 * we know that the node will become empty, and so, we can clear
1457 * it for N_MEMORY as well.
1459 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
1461 if (nr_pages >= present_pages)
1462 arg->status_change_nid = zone_to_nid(zone);
1465 static void node_states_clear_node(int node, struct memory_notify *arg)
1467 if (arg->status_change_nid_normal >= 0)
1468 node_clear_state(node, N_NORMAL_MEMORY);
1470 if (arg->status_change_nid_high >= 0)
1471 node_clear_state(node, N_HIGH_MEMORY);
1473 if (arg->status_change_nid >= 0)
1474 node_clear_state(node, N_MEMORY);
1477 static int count_system_ram_pages_cb(unsigned long start_pfn,
1478 unsigned long nr_pages, void *data)
1480 unsigned long *nr_system_ram_pages = data;
1482 *nr_system_ram_pages += nr_pages;
1486 static int __ref __offline_pages(unsigned long start_pfn,
1487 unsigned long end_pfn)
1489 unsigned long pfn, nr_pages = 0;
1490 unsigned long offlined_pages = 0;
1491 int ret, node, nr_isolate_pageblock;
1492 unsigned long flags;
1493 unsigned long valid_start, valid_end;
1495 struct memory_notify arg;
1498 mem_hotplug_begin();
1501 * Don't allow to offline memory blocks that contain holes.
1502 * Consequently, memory blocks with holes can never get onlined
1503 * via the hotplug path - online_pages() - as hotplugged memory has
1504 * no holes. This way, we e.g., don't have to worry about marking
1505 * memory holes PG_reserved, don't need pfn_valid() checks, and can
1506 * avoid using walk_system_ram_range() later.
1508 walk_system_ram_range(start_pfn, end_pfn - start_pfn, &nr_pages,
1509 count_system_ram_pages_cb);
1510 if (nr_pages != end_pfn - start_pfn) {
1512 reason = "memory holes";
1513 goto failed_removal;
1516 /* This makes hotplug much easier...and readable.
1517 we assume this for now. .*/
1518 if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start,
1521 reason = "multizone range";
1522 goto failed_removal;
1525 zone = page_zone(pfn_to_page(valid_start));
1526 node = zone_to_nid(zone);
1528 /* set above range as isolated */
1529 ret = start_isolate_page_range(start_pfn, end_pfn,
1531 MEMORY_OFFLINE | REPORT_FAILURE);
1533 reason = "failure to isolate range";
1534 goto failed_removal;
1536 nr_isolate_pageblock = ret;
1538 arg.start_pfn = start_pfn;
1539 arg.nr_pages = nr_pages;
1540 node_states_check_changes_offline(nr_pages, zone, &arg);
1542 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1543 ret = notifier_to_errno(ret);
1545 reason = "notifier failure";
1546 goto failed_removal_isolated;
1550 for (pfn = start_pfn; pfn;) {
1551 if (signal_pending(current)) {
1553 reason = "signal backoff";
1554 goto failed_removal_isolated;
1558 lru_add_drain_all();
1560 pfn = scan_movable_pages(pfn, end_pfn);
1563 * TODO: fatal migration failures should bail
1566 do_migrate_range(pfn, end_pfn);
1571 * Dissolve free hugepages in the memory block before doing
1572 * offlining actually in order to make hugetlbfs's object
1573 * counting consistent.
1575 ret = dissolve_free_huge_pages(start_pfn, end_pfn);
1577 reason = "failure to dissolve huge pages";
1578 goto failed_removal_isolated;
1581 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn,
1582 NULL, check_pages_isolated_cb);
1585 /* Ok, all of our target is isolated.
1586 We cannot do rollback at this point. */
1587 walk_system_ram_range(start_pfn, end_pfn - start_pfn,
1588 &offlined_pages, offline_isolated_pages_cb);
1589 pr_info("Offlined Pages %ld\n", offlined_pages);
1591 * Onlining will reset pagetype flags and makes migrate type
1592 * MOVABLE, so just need to decrease the number of isolated
1593 * pageblocks zone counter here.
1595 spin_lock_irqsave(&zone->lock, flags);
1596 zone->nr_isolate_pageblock -= nr_isolate_pageblock;
1597 spin_unlock_irqrestore(&zone->lock, flags);
1599 /* removal success */
1600 adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
1601 zone->present_pages -= offlined_pages;
1603 pgdat_resize_lock(zone->zone_pgdat, &flags);
1604 zone->zone_pgdat->node_present_pages -= offlined_pages;
1605 pgdat_resize_unlock(zone->zone_pgdat, &flags);
1607 init_per_zone_wmark_min();
1609 if (!populated_zone(zone)) {
1610 zone_pcp_reset(zone);
1611 build_all_zonelists(NULL);
1613 zone_pcp_update(zone);
1615 node_states_clear_node(node, &arg);
1616 if (arg.status_change_nid >= 0) {
1618 kcompactd_stop(node);
1621 vm_total_pages = nr_free_pagecache_pages();
1622 writeback_set_ratelimit();
1624 memory_notify(MEM_OFFLINE, &arg);
1625 remove_pfn_range_from_zone(zone, start_pfn, nr_pages);
1629 failed_removal_isolated:
1630 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1631 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1633 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
1634 (unsigned long long) start_pfn << PAGE_SHIFT,
1635 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
1637 /* pushback to free area */
1642 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1644 return __offline_pages(start_pfn, start_pfn + nr_pages);
1647 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1649 int ret = !is_memblock_offlined(mem);
1651 if (unlikely(ret)) {
1652 phys_addr_t beginpa, endpa;
1654 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1655 endpa = beginpa + memory_block_size_bytes() - 1;
1656 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1664 static int check_cpu_on_node(pg_data_t *pgdat)
1668 for_each_present_cpu(cpu) {
1669 if (cpu_to_node(cpu) == pgdat->node_id)
1671 * the cpu on this node isn't removed, and we can't
1672 * offline this node.
1680 static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg)
1682 int nid = *(int *)arg;
1685 * If a memory block belongs to multiple nodes, the stored nid is not
1686 * reliable. However, such blocks are always online (e.g., cannot get
1687 * offlined) and, therefore, are still spanned by the node.
1689 return mem->nid == nid ? -EEXIST : 0;
1696 * Offline a node if all memory sections and cpus of the node are removed.
1698 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1699 * and online/offline operations before this call.
1701 void try_offline_node(int nid)
1703 pg_data_t *pgdat = NODE_DATA(nid);
1707 * If the node still spans pages (especially ZONE_DEVICE), don't
1708 * offline it. A node spans memory after move_pfn_range_to_zone(),
1709 * e.g., after the memory block was onlined.
1711 if (pgdat->node_spanned_pages)
1715 * Especially offline memory blocks might not be spanned by the
1716 * node. They will get spanned by the node once they get onlined.
1717 * However, they link to the node in sysfs and can get onlined later.
1719 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb);
1723 if (check_cpu_on_node(pgdat))
1727 * all memory/cpu of this node are removed, we can offline this
1730 node_set_offline(nid);
1731 unregister_one_node(nid);
1733 EXPORT_SYMBOL(try_offline_node);
1735 static void __release_memory_resource(resource_size_t start,
1736 resource_size_t size)
1741 * When removing memory in the same granularity as it was added,
1742 * this function never fails. It might only fail if resources
1743 * have to be adjusted or split. We'll ignore the error, as
1744 * removing of memory cannot fail.
1746 ret = release_mem_region_adjustable(&iomem_resource, start, size);
1748 resource_size_t endres = start + size - 1;
1750 pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
1751 &start, &endres, ret);
1755 static int __ref try_remove_memory(int nid, u64 start, u64 size)
1759 BUG_ON(check_hotplug_memory_range(start, size));
1762 * All memory blocks must be offlined before removing memory. Check
1763 * whether all memory blocks in question are offline and return error
1764 * if this is not the case.
1766 rc = walk_memory_blocks(start, size, NULL, check_memblock_offlined_cb);
1770 /* remove memmap entry */
1771 firmware_map_remove(start, start + size, "System RAM");
1774 * Memory block device removal under the device_hotplug_lock is
1775 * a barrier against racing online attempts.
1777 remove_memory_block_devices(start, size);
1779 mem_hotplug_begin();
1781 arch_remove_memory(nid, start, size, NULL);
1782 memblock_free(start, size);
1783 memblock_remove(start, size);
1784 __release_memory_resource(start, size);
1786 try_offline_node(nid);
1796 * @start: physical address of the region to remove
1797 * @size: size of the region to remove
1799 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1800 * and online/offline operations before this call, as required by
1801 * try_offline_node().
1803 void __remove_memory(int nid, u64 start, u64 size)
1807 * trigger BUG() if some memory is not offlined prior to calling this
1810 if (try_remove_memory(nid, start, size))
1815 * Remove memory if every memory block is offline, otherwise return -EBUSY is
1816 * some memory is not offline
1818 int remove_memory(int nid, u64 start, u64 size)
1822 lock_device_hotplug();
1823 rc = try_remove_memory(nid, start, size);
1824 unlock_device_hotplug();
1828 EXPORT_SYMBOL_GPL(remove_memory);
1829 #endif /* CONFIG_MEMORY_HOTREMOVE */