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);
138 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
139 void get_page_bootmem(unsigned long info, struct page *page,
142 page->freelist = (void *)type;
143 SetPagePrivate(page);
144 set_page_private(page, info);
148 void put_page_bootmem(struct page *page)
152 type = (unsigned long) page->freelist;
153 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
154 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
156 if (page_ref_dec_return(page) == 1) {
157 page->freelist = NULL;
158 ClearPagePrivate(page);
159 set_page_private(page, 0);
160 INIT_LIST_HEAD(&page->lru);
161 free_reserved_page(page);
165 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
166 #ifndef CONFIG_SPARSEMEM_VMEMMAP
167 static void register_page_bootmem_info_section(unsigned long start_pfn)
169 unsigned long mapsize, section_nr, i;
170 struct mem_section *ms;
171 struct page *page, *memmap;
172 struct mem_section_usage *usage;
174 section_nr = pfn_to_section_nr(start_pfn);
175 ms = __nr_to_section(section_nr);
177 /* Get section's memmap address */
178 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
181 * Get page for the memmap's phys address
182 * XXX: need more consideration for sparse_vmemmap...
184 page = virt_to_page(memmap);
185 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
186 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
188 /* remember memmap's page */
189 for (i = 0; i < mapsize; i++, page++)
190 get_page_bootmem(section_nr, page, SECTION_INFO);
193 page = virt_to_page(usage);
195 mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT;
197 for (i = 0; i < mapsize; i++, page++)
198 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
201 #else /* CONFIG_SPARSEMEM_VMEMMAP */
202 static void register_page_bootmem_info_section(unsigned long start_pfn)
204 unsigned long mapsize, section_nr, i;
205 struct mem_section *ms;
206 struct page *page, *memmap;
207 struct mem_section_usage *usage;
209 section_nr = pfn_to_section_nr(start_pfn);
210 ms = __nr_to_section(section_nr);
212 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
214 register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
217 page = virt_to_page(usage);
219 mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT;
221 for (i = 0; i < mapsize; i++, page++)
222 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
224 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
226 void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
228 unsigned long i, pfn, end_pfn, nr_pages;
229 int node = pgdat->node_id;
232 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
233 page = virt_to_page(pgdat);
235 for (i = 0; i < nr_pages; i++, page++)
236 get_page_bootmem(node, page, NODE_INFO);
238 pfn = pgdat->node_start_pfn;
239 end_pfn = pgdat_end_pfn(pgdat);
241 /* register section info */
242 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
244 * Some platforms can assign the same pfn to multiple nodes - on
245 * node0 as well as nodeN. To avoid registering a pfn against
246 * multiple nodes we check that this pfn does not already
247 * reside in some other nodes.
249 if (pfn_valid(pfn) && (early_pfn_to_nid(pfn) == node))
250 register_page_bootmem_info_section(pfn);
253 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
255 static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
256 struct vmem_altmap *altmap)
260 if (pfn_valid(phys_start_pfn))
263 ret = sparse_add_one_section(nid, phys_start_pfn, altmap);
264 return ret < 0 ? ret : 0;
268 * Reasonably generic function for adding memory. It is
269 * expected that archs that support memory hotplug will
270 * call this function after deciding the zone to which to
273 int __ref __add_pages(int nid, unsigned long phys_start_pfn,
274 unsigned long nr_pages, struct mhp_restrictions *restrictions)
278 int start_sec, end_sec;
279 struct vmem_altmap *altmap = restrictions->altmap;
281 /* during initialize mem_map, align hot-added range to section */
282 start_sec = pfn_to_section_nr(phys_start_pfn);
283 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
287 * Validate altmap is within bounds of the total request
289 if (altmap->base_pfn != phys_start_pfn
290 || vmem_altmap_offset(altmap) > nr_pages) {
291 pr_warn_once("memory add fail, invalid altmap\n");
298 for (i = start_sec; i <= end_sec; i++) {
299 err = __add_section(nid, section_nr_to_pfn(i), altmap);
302 * EEXIST is finally dealt with by ioresource collision
303 * check. see add_memory() => register_memory_resource()
304 * Warning will be printed if there is collision.
306 if (err && (err != -EEXIST))
311 vmemmap_populate_print_last();
316 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
317 static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
318 unsigned long start_pfn,
319 unsigned long end_pfn)
321 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
322 if (unlikely(!pfn_valid(start_pfn)))
325 if (unlikely(pfn_to_nid(start_pfn) != nid))
328 if (zone && zone != page_zone(pfn_to_page(start_pfn)))
337 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
338 static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
339 unsigned long start_pfn,
340 unsigned long end_pfn)
344 /* pfn is the end pfn of a memory section. */
346 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) {
347 if (unlikely(!pfn_valid(pfn)))
350 if (unlikely(pfn_to_nid(pfn) != nid))
353 if (zone && zone != page_zone(pfn_to_page(pfn)))
362 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
363 unsigned long end_pfn)
365 unsigned long zone_start_pfn = zone->zone_start_pfn;
366 unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
367 unsigned long zone_end_pfn = z;
369 int nid = zone_to_nid(zone);
371 zone_span_writelock(zone);
372 if (zone_start_pfn == start_pfn) {
374 * If the section is smallest section in the zone, it need
375 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
376 * In this case, we find second smallest valid mem_section
377 * for shrinking zone.
379 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
382 zone->zone_start_pfn = pfn;
383 zone->spanned_pages = zone_end_pfn - pfn;
385 } else if (zone_end_pfn == end_pfn) {
387 * If the section is biggest section in the zone, it need
388 * shrink zone->spanned_pages.
389 * In this case, we find second biggest valid mem_section for
392 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
395 zone->spanned_pages = pfn - zone_start_pfn + 1;
399 * The section is not biggest or smallest mem_section in the zone, it
400 * only creates a hole in the zone. So in this case, we need not
401 * change the zone. But perhaps, the zone has only hole data. Thus
402 * it check the zone has only hole or not.
404 pfn = zone_start_pfn;
405 for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUBSECTION) {
406 if (unlikely(!pfn_valid(pfn)))
409 if (page_zone(pfn_to_page(pfn)) != zone)
412 /* Skip range to be removed */
413 if (pfn >= start_pfn && pfn < end_pfn)
416 /* If we find valid section, we have nothing to do */
417 zone_span_writeunlock(zone);
421 /* The zone has no valid section */
422 zone->zone_start_pfn = 0;
423 zone->spanned_pages = 0;
424 zone_span_writeunlock(zone);
427 static void shrink_pgdat_span(struct pglist_data *pgdat,
428 unsigned long start_pfn, unsigned long end_pfn)
430 unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
431 unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */
432 unsigned long pgdat_end_pfn = p;
434 int nid = pgdat->node_id;
436 if (pgdat_start_pfn == start_pfn) {
438 * If the section is smallest section in the pgdat, it need
439 * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
440 * In this case, we find second smallest valid mem_section
441 * for shrinking zone.
443 pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
446 pgdat->node_start_pfn = pfn;
447 pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
449 } else if (pgdat_end_pfn == end_pfn) {
451 * If the section is biggest section in the pgdat, it need
452 * shrink pgdat->node_spanned_pages.
453 * In this case, we find second biggest valid mem_section for
456 pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
459 pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
463 * If the section is not biggest or smallest mem_section in the pgdat,
464 * it only creates a hole in the pgdat. So in this case, we need not
466 * But perhaps, the pgdat has only hole data. Thus it check the pgdat
467 * has only hole or not.
469 pfn = pgdat_start_pfn;
470 for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SUBSECTION) {
471 if (unlikely(!pfn_valid(pfn)))
474 if (pfn_to_nid(pfn) != nid)
477 /* Skip range to be removed */
478 if (pfn >= start_pfn && pfn < end_pfn)
481 /* If we find valid section, we have nothing to do */
485 /* The pgdat has no valid section */
486 pgdat->node_start_pfn = 0;
487 pgdat->node_spanned_pages = 0;
490 static void __remove_zone(struct zone *zone, unsigned long start_pfn)
492 struct pglist_data *pgdat = zone->zone_pgdat;
493 int nr_pages = PAGES_PER_SECTION;
496 pgdat_resize_lock(zone->zone_pgdat, &flags);
497 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
498 shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
499 pgdat_resize_unlock(zone->zone_pgdat, &flags);
502 static void __remove_section(struct zone *zone, struct mem_section *ms,
503 unsigned long map_offset,
504 struct vmem_altmap *altmap)
506 unsigned long start_pfn;
509 if (WARN_ON_ONCE(!valid_section(ms)))
512 scn_nr = __section_nr(ms);
513 start_pfn = section_nr_to_pfn((unsigned long)scn_nr);
514 __remove_zone(zone, start_pfn);
516 sparse_remove_one_section(ms, map_offset, altmap);
520 * __remove_pages() - remove sections of pages from a zone
521 * @zone: zone from which pages need to be removed
522 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
523 * @nr_pages: number of pages to remove (must be multiple of section size)
524 * @altmap: alternative device page map or %NULL if default memmap is used
526 * Generic helper function to remove section mappings and sysfs entries
527 * for the section of the memory we are removing. Caller needs to make
528 * sure that pages are marked reserved and zones are adjust properly by
529 * calling offline_pages().
531 void __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
532 unsigned long nr_pages, struct vmem_altmap *altmap)
535 unsigned long map_offset = 0;
536 int sections_to_remove;
538 map_offset = vmem_altmap_offset(altmap);
540 clear_zone_contiguous(zone);
543 * We can only remove entire sections
545 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
546 BUG_ON(nr_pages % PAGES_PER_SECTION);
548 sections_to_remove = nr_pages / PAGES_PER_SECTION;
549 for (i = 0; i < sections_to_remove; i++) {
550 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
553 __remove_section(zone, __pfn_to_section(pfn), map_offset,
558 set_zone_contiguous(zone);
561 int set_online_page_callback(online_page_callback_t callback)
566 mutex_lock(&online_page_callback_lock);
568 if (online_page_callback == generic_online_page) {
569 online_page_callback = callback;
573 mutex_unlock(&online_page_callback_lock);
578 EXPORT_SYMBOL_GPL(set_online_page_callback);
580 int restore_online_page_callback(online_page_callback_t callback)
585 mutex_lock(&online_page_callback_lock);
587 if (online_page_callback == callback) {
588 online_page_callback = generic_online_page;
592 mutex_unlock(&online_page_callback_lock);
597 EXPORT_SYMBOL_GPL(restore_online_page_callback);
599 void __online_page_set_limits(struct page *page)
602 EXPORT_SYMBOL_GPL(__online_page_set_limits);
604 void __online_page_increment_counters(struct page *page)
606 adjust_managed_page_count(page, 1);
608 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
610 void __online_page_free(struct page *page)
612 __free_reserved_page(page);
614 EXPORT_SYMBOL_GPL(__online_page_free);
616 static void generic_online_page(struct page *page, unsigned int order)
618 kernel_map_pages(page, 1 << order, 1);
619 __free_pages_core(page, order);
620 totalram_pages_add(1UL << order);
621 #ifdef CONFIG_HIGHMEM
622 if (PageHighMem(page))
623 totalhigh_pages_add(1UL << order);
627 static int online_pages_blocks(unsigned long start, unsigned long nr_pages)
629 unsigned long end = start + nr_pages;
630 int order, onlined_pages = 0;
632 while (start < end) {
633 order = min(MAX_ORDER - 1,
634 get_order(PFN_PHYS(end) - PFN_PHYS(start)));
635 (*online_page_callback)(pfn_to_page(start), order);
637 onlined_pages += (1UL << order);
638 start += (1UL << order);
640 return onlined_pages;
643 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
646 unsigned long onlined_pages = *(unsigned long *)arg;
648 if (PageReserved(pfn_to_page(start_pfn)))
649 onlined_pages += online_pages_blocks(start_pfn, nr_pages);
651 online_mem_sections(start_pfn, start_pfn + nr_pages);
653 *(unsigned long *)arg = onlined_pages;
657 /* check which state of node_states will be changed when online memory */
658 static void node_states_check_changes_online(unsigned long nr_pages,
659 struct zone *zone, struct memory_notify *arg)
661 int nid = zone_to_nid(zone);
663 arg->status_change_nid = NUMA_NO_NODE;
664 arg->status_change_nid_normal = NUMA_NO_NODE;
665 arg->status_change_nid_high = NUMA_NO_NODE;
667 if (!node_state(nid, N_MEMORY))
668 arg->status_change_nid = nid;
669 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
670 arg->status_change_nid_normal = nid;
671 #ifdef CONFIG_HIGHMEM
672 if (zone_idx(zone) <= ZONE_HIGHMEM && !node_state(nid, N_HIGH_MEMORY))
673 arg->status_change_nid_high = nid;
677 static void node_states_set_node(int node, struct memory_notify *arg)
679 if (arg->status_change_nid_normal >= 0)
680 node_set_state(node, N_NORMAL_MEMORY);
682 if (arg->status_change_nid_high >= 0)
683 node_set_state(node, N_HIGH_MEMORY);
685 if (arg->status_change_nid >= 0)
686 node_set_state(node, N_MEMORY);
689 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
690 unsigned long nr_pages)
692 unsigned long old_end_pfn = zone_end_pfn(zone);
694 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
695 zone->zone_start_pfn = start_pfn;
697 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
700 static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
701 unsigned long nr_pages)
703 unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
705 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
706 pgdat->node_start_pfn = start_pfn;
708 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
711 void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
712 unsigned long nr_pages, struct vmem_altmap *altmap)
714 struct pglist_data *pgdat = zone->zone_pgdat;
715 int nid = pgdat->node_id;
718 clear_zone_contiguous(zone);
720 /* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */
721 pgdat_resize_lock(pgdat, &flags);
722 zone_span_writelock(zone);
723 if (zone_is_empty(zone))
724 init_currently_empty_zone(zone, start_pfn, nr_pages);
725 resize_zone_range(zone, start_pfn, nr_pages);
726 zone_span_writeunlock(zone);
727 resize_pgdat_range(pgdat, start_pfn, nr_pages);
728 pgdat_resize_unlock(pgdat, &flags);
731 * TODO now we have a visible range of pages which are not associated
732 * with their zone properly. Not nice but set_pfnblock_flags_mask
733 * expects the zone spans the pfn range. All the pages in the range
734 * are reserved so nobody should be touching them so we should be safe
736 memmap_init_zone(nr_pages, nid, zone_idx(zone), start_pfn,
737 MEMMAP_HOTPLUG, altmap);
739 set_zone_contiguous(zone);
743 * Returns a default kernel memory zone for the given pfn range.
744 * If no kernel zone covers this pfn range it will automatically go
745 * to the ZONE_NORMAL.
747 static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
748 unsigned long nr_pages)
750 struct pglist_data *pgdat = NODE_DATA(nid);
753 for (zid = 0; zid <= ZONE_NORMAL; zid++) {
754 struct zone *zone = &pgdat->node_zones[zid];
756 if (zone_intersects(zone, start_pfn, nr_pages))
760 return &pgdat->node_zones[ZONE_NORMAL];
763 static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
764 unsigned long nr_pages)
766 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
768 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
769 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
770 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
773 * We inherit the existing zone in a simple case where zones do not
774 * overlap in the given range
776 if (in_kernel ^ in_movable)
777 return (in_kernel) ? kernel_zone : movable_zone;
780 * If the range doesn't belong to any zone or two zones overlap in the
781 * given range then we use movable zone only if movable_node is
782 * enabled because we always online to a kernel zone by default.
784 return movable_node_enabled ? movable_zone : kernel_zone;
787 struct zone * zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
788 unsigned long nr_pages)
790 if (online_type == MMOP_ONLINE_KERNEL)
791 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
793 if (online_type == MMOP_ONLINE_MOVABLE)
794 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
796 return default_zone_for_pfn(nid, start_pfn, nr_pages);
800 * Associates the given pfn range with the given node and the zone appropriate
801 * for the given online type.
803 static struct zone * __meminit move_pfn_range(int online_type, int nid,
804 unsigned long start_pfn, unsigned long nr_pages)
808 zone = zone_for_pfn_range(online_type, nid, start_pfn, nr_pages);
809 move_pfn_range_to_zone(zone, start_pfn, nr_pages, NULL);
813 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
816 unsigned long onlined_pages = 0;
818 int need_zonelists_rebuild = 0;
821 struct memory_notify arg;
822 struct memory_block *mem;
827 * We can't use pfn_to_nid() because nid might be stored in struct page
828 * which is not yet initialized. Instead, we find nid from memory block.
830 mem = find_memory_block(__pfn_to_section(pfn));
832 put_device(&mem->dev);
834 /* associate pfn range with the zone */
835 zone = move_pfn_range(online_type, nid, pfn, nr_pages);
838 arg.nr_pages = nr_pages;
839 node_states_check_changes_online(nr_pages, zone, &arg);
841 ret = memory_notify(MEM_GOING_ONLINE, &arg);
842 ret = notifier_to_errno(ret);
844 goto failed_addition;
847 * If this zone is not populated, then it is not in zonelist.
848 * This means the page allocator ignores this zone.
849 * So, zonelist must be updated after online.
851 if (!populated_zone(zone)) {
852 need_zonelists_rebuild = 1;
853 setup_zone_pageset(zone);
856 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
859 if (need_zonelists_rebuild)
860 zone_pcp_reset(zone);
861 goto failed_addition;
864 zone->present_pages += onlined_pages;
866 pgdat_resize_lock(zone->zone_pgdat, &flags);
867 zone->zone_pgdat->node_present_pages += onlined_pages;
868 pgdat_resize_unlock(zone->zone_pgdat, &flags);
873 node_states_set_node(nid, &arg);
874 if (need_zonelists_rebuild)
875 build_all_zonelists(NULL);
877 zone_pcp_update(zone);
880 init_per_zone_wmark_min();
887 vm_total_pages = nr_free_pagecache_pages();
889 writeback_set_ratelimit();
892 memory_notify(MEM_ONLINE, &arg);
897 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
898 (unsigned long long) pfn << PAGE_SHIFT,
899 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
900 memory_notify(MEM_CANCEL_ONLINE, &arg);
904 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
906 static void reset_node_present_pages(pg_data_t *pgdat)
910 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
911 z->present_pages = 0;
913 pgdat->node_present_pages = 0;
916 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
917 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
919 struct pglist_data *pgdat;
920 unsigned long start_pfn = PFN_DOWN(start);
922 pgdat = NODE_DATA(nid);
924 pgdat = arch_alloc_nodedata(nid);
928 arch_refresh_nodedata(nid, pgdat);
931 * Reset the nr_zones, order and classzone_idx before reuse.
932 * Note that kswapd will init kswapd_classzone_idx properly
933 * when it starts in the near future.
936 pgdat->kswapd_order = 0;
937 pgdat->kswapd_classzone_idx = 0;
940 /* we can use NODE_DATA(nid) from here */
942 pgdat->node_id = nid;
943 pgdat->node_start_pfn = start_pfn;
945 /* init node's zones as empty zones, we don't have any present pages.*/
946 free_area_init_core_hotplug(nid);
947 pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);
950 * The node we allocated has no zone fallback lists. For avoiding
951 * to access not-initialized zonelist, build here.
953 build_all_zonelists(pgdat);
956 * When memory is hot-added, all the memory is in offline state. So
957 * clear all zones' present_pages because they will be updated in
958 * online_pages() and offline_pages().
960 reset_node_managed_pages(pgdat);
961 reset_node_present_pages(pgdat);
966 static void rollback_node_hotadd(int nid)
968 pg_data_t *pgdat = NODE_DATA(nid);
970 arch_refresh_nodedata(nid, NULL);
971 free_percpu(pgdat->per_cpu_nodestats);
972 arch_free_nodedata(pgdat);
978 * try_online_node - online a node if offlined
980 * @start: start addr of the node
981 * @set_node_online: Whether we want to online the node
982 * called by cpu_up() to online a node without onlined memory.
985 * 1 -> a new node has been allocated
986 * 0 -> the node is already online
987 * -ENOMEM -> the node could not be allocated
989 static int __try_online_node(int nid, u64 start, bool set_node_online)
994 if (node_online(nid))
997 pgdat = hotadd_new_pgdat(nid, start);
999 pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1004 if (set_node_online) {
1005 node_set_online(nid);
1006 ret = register_one_node(nid);
1014 * Users of this function always want to online/register the node
1016 int try_online_node(int nid)
1020 mem_hotplug_begin();
1021 ret = __try_online_node(nid, 0, true);
1026 static int check_hotplug_memory_range(u64 start, u64 size)
1028 /* memory range must be block size aligned */
1029 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
1030 !IS_ALIGNED(size, memory_block_size_bytes())) {
1031 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1032 memory_block_size_bytes(), start, size);
1039 static int online_memory_block(struct memory_block *mem, void *arg)
1041 return device_online(&mem->dev);
1045 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1046 * and online/offline operations (triggered e.g. by sysfs).
1048 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1050 int __ref add_memory_resource(int nid, struct resource *res)
1052 struct mhp_restrictions restrictions = {};
1054 bool new_node = false;
1058 size = resource_size(res);
1060 ret = check_hotplug_memory_range(start, size);
1064 mem_hotplug_begin();
1067 * Add new range to memblock so that when hotadd_new_pgdat() is called
1068 * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
1069 * this new range and calculate total pages correctly. The range will
1070 * be removed at hot-remove time.
1072 memblock_add_node(start, size, nid);
1074 ret = __try_online_node(nid, start, false);
1079 /* call arch's memory hotadd */
1080 ret = arch_add_memory(nid, start, size, &restrictions);
1084 /* create memory block devices after memory was added */
1085 ret = create_memory_block_devices(start, size);
1087 arch_remove_memory(nid, start, size, NULL);
1092 /* If sysfs file of new node can't be created, cpu on the node
1093 * can't be hot-added. There is no rollback way now.
1094 * So, check by BUG_ON() to catch it reluctantly..
1095 * We online node here. We can't roll back from here.
1097 node_set_online(nid);
1098 ret = __register_one_node(nid);
1102 /* link memory sections under this node.*/
1103 ret = link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1));
1106 /* create new memmap entry */
1107 firmware_map_add_hotplug(start, start + size, "System RAM");
1109 /* device_online() will take the lock when calling online_pages() */
1112 /* online pages if requested */
1113 if (memhp_auto_online)
1114 walk_memory_blocks(start, size, NULL, online_memory_block);
1118 /* rollback pgdat allocation and others */
1120 rollback_node_hotadd(nid);
1121 memblock_remove(start, size);
1126 /* requires device_hotplug_lock, see add_memory_resource() */
1127 int __ref __add_memory(int nid, u64 start, u64 size)
1129 struct resource *res;
1132 res = register_memory_resource(start, size);
1134 return PTR_ERR(res);
1136 ret = add_memory_resource(nid, res);
1138 release_memory_resource(res);
1142 int add_memory(int nid, u64 start, u64 size)
1146 lock_device_hotplug();
1147 rc = __add_memory(nid, start, size);
1148 unlock_device_hotplug();
1152 EXPORT_SYMBOL_GPL(add_memory);
1154 #ifdef CONFIG_MEMORY_HOTREMOVE
1156 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1157 * set and the size of the free page is given by page_order(). Using this,
1158 * the function determines if the pageblock contains only free pages.
1159 * Due to buddy contraints, a free page at least the size of a pageblock will
1160 * be located at the start of the pageblock
1162 static inline int pageblock_free(struct page *page)
1164 return PageBuddy(page) && page_order(page) >= pageblock_order;
1167 /* Return the pfn of the start of the next active pageblock after a given pfn */
1168 static unsigned long next_active_pageblock(unsigned long pfn)
1170 struct page *page = pfn_to_page(pfn);
1172 /* Ensure the starting page is pageblock-aligned */
1173 BUG_ON(pfn & (pageblock_nr_pages - 1));
1175 /* If the entire pageblock is free, move to the end of free page */
1176 if (pageblock_free(page)) {
1178 /* be careful. we don't have locks, page_order can be changed.*/
1179 order = page_order(page);
1180 if ((order < MAX_ORDER) && (order >= pageblock_order))
1181 return pfn + (1 << order);
1184 return pfn + pageblock_nr_pages;
1187 static bool is_pageblock_removable_nolock(unsigned long pfn)
1189 struct page *page = pfn_to_page(pfn);
1193 * We have to be careful here because we are iterating over memory
1194 * sections which are not zone aware so we might end up outside of
1195 * the zone but still within the section.
1196 * We have to take care about the node as well. If the node is offline
1197 * its NODE_DATA will be NULL - see page_zone.
1199 if (!node_online(page_to_nid(page)))
1202 zone = page_zone(page);
1203 pfn = page_to_pfn(page);
1204 if (!zone_spans_pfn(zone, pfn))
1207 return !has_unmovable_pages(zone, page, 0, MIGRATE_MOVABLE, SKIP_HWPOISON);
1210 /* Checks if this range of memory is likely to be hot-removable. */
1211 bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1213 unsigned long end_pfn, pfn;
1215 end_pfn = min(start_pfn + nr_pages,
1216 zone_end_pfn(page_zone(pfn_to_page(start_pfn))));
1218 /* Check the starting page of each pageblock within the range */
1219 for (pfn = start_pfn; pfn < end_pfn; pfn = next_active_pageblock(pfn)) {
1220 if (!is_pageblock_removable_nolock(pfn))
1225 /* All pageblocks in the memory block are likely to be hot-removable */
1230 * Confirm all pages in a range [start, end) belong to the same zone.
1231 * When true, return its valid [start, end).
1233 int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
1234 unsigned long *valid_start, unsigned long *valid_end)
1236 unsigned long pfn, sec_end_pfn;
1237 unsigned long start, end;
1238 struct zone *zone = NULL;
1241 for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1);
1243 pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) {
1244 /* Make sure the memory section is present first */
1245 if (!present_section_nr(pfn_to_section_nr(pfn)))
1247 for (; pfn < sec_end_pfn && pfn < end_pfn;
1248 pfn += MAX_ORDER_NR_PAGES) {
1250 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1251 while ((i < MAX_ORDER_NR_PAGES) &&
1252 !pfn_valid_within(pfn + i))
1254 if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn)
1256 /* Check if we got outside of the zone */
1257 if (zone && !zone_spans_pfn(zone, pfn + i))
1259 page = pfn_to_page(pfn + i);
1260 if (zone && page_zone(page) != zone)
1264 zone = page_zone(page);
1265 end = pfn + MAX_ORDER_NR_PAGES;
1270 *valid_start = start;
1271 *valid_end = min(end, end_pfn);
1279 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1280 * non-lru movable pages and hugepages). We scan pfn because it's much
1281 * easier than scanning over linked list. This function returns the pfn
1282 * of the first found movable page if it's found, otherwise 0.
1284 static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1288 for (pfn = start; pfn < end; pfn++) {
1289 struct page *page, *head;
1292 if (!pfn_valid(pfn))
1294 page = pfn_to_page(pfn);
1297 if (__PageMovable(page))
1300 if (!PageHuge(page))
1302 head = compound_head(page);
1303 if (page_huge_active(head))
1305 skip = (1 << compound_order(head)) - (page - head);
1311 static struct page *new_node_page(struct page *page, unsigned long private)
1313 int nid = page_to_nid(page);
1314 nodemask_t nmask = node_states[N_MEMORY];
1317 * try to allocate from a different node but reuse this node if there
1318 * are no other online nodes to be used (e.g. we are offlining a part
1319 * of the only existing node)
1321 node_clear(nid, nmask);
1322 if (nodes_empty(nmask))
1323 node_set(nid, nmask);
1325 return new_page_nodemask(page, nid, &nmask);
1329 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1336 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1337 if (!pfn_valid(pfn))
1339 page = pfn_to_page(pfn);
1341 if (PageHuge(page)) {
1342 struct page *head = compound_head(page);
1343 pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1;
1344 isolate_huge_page(head, &source);
1346 } else if (PageTransHuge(page))
1347 pfn = page_to_pfn(compound_head(page))
1348 + hpage_nr_pages(page) - 1;
1351 * HWPoison pages have elevated reference counts so the migration would
1352 * fail on them. It also doesn't make any sense to migrate them in the
1353 * first place. Still try to unmap such a page in case it is still mapped
1354 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1355 * the unmap as the catch all safety net).
1357 if (PageHWPoison(page)) {
1358 if (WARN_ON(PageLRU(page)))
1359 isolate_lru_page(page);
1360 if (page_mapped(page))
1361 try_to_unmap(page, TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS);
1365 if (!get_page_unless_zero(page))
1368 * We can skip free pages. And we can deal with pages on
1369 * LRU and non-lru movable pages.
1372 ret = isolate_lru_page(page);
1374 ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
1375 if (!ret) { /* Success */
1376 list_add_tail(&page->lru, &source);
1377 if (!__PageMovable(page))
1378 inc_node_page_state(page, NR_ISOLATED_ANON +
1379 page_is_file_cache(page));
1382 pr_warn("failed to isolate pfn %lx\n", pfn);
1383 dump_page(page, "isolation failed");
1387 if (!list_empty(&source)) {
1388 /* Allocate a new page from the nearest neighbor node */
1389 ret = migrate_pages(&source, new_node_page, NULL, 0,
1390 MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1392 list_for_each_entry(page, &source, lru) {
1393 pr_warn("migrating pfn %lx failed ret:%d ",
1394 page_to_pfn(page), ret);
1395 dump_page(page, "migration failure");
1397 putback_movable_pages(&source);
1405 * remove from free_area[] and mark all as Reserved.
1408 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1411 unsigned long *offlined_pages = (unsigned long *)data;
1413 *offlined_pages += __offline_isolated_pages(start, start + nr_pages);
1418 * Check all pages in range, recoreded as memory resource, are isolated.
1421 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1424 return test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1427 static int __init cmdline_parse_movable_node(char *p)
1429 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1430 movable_node_enabled = true;
1432 pr_warn("movable_node parameter depends on CONFIG_HAVE_MEMBLOCK_NODE_MAP to work properly\n");
1436 early_param("movable_node", cmdline_parse_movable_node);
1438 /* check which state of node_states will be changed when offline memory */
1439 static void node_states_check_changes_offline(unsigned long nr_pages,
1440 struct zone *zone, struct memory_notify *arg)
1442 struct pglist_data *pgdat = zone->zone_pgdat;
1443 unsigned long present_pages = 0;
1446 arg->status_change_nid = NUMA_NO_NODE;
1447 arg->status_change_nid_normal = NUMA_NO_NODE;
1448 arg->status_change_nid_high = NUMA_NO_NODE;
1451 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1452 * If the memory to be offline is within the range
1453 * [0..ZONE_NORMAL], and it is the last present memory there,
1454 * the zones in that range will become empty after the offlining,
1455 * thus we can determine that we need to clear the node from
1456 * node_states[N_NORMAL_MEMORY].
1458 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1459 present_pages += pgdat->node_zones[zt].present_pages;
1460 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
1461 arg->status_change_nid_normal = zone_to_nid(zone);
1463 #ifdef CONFIG_HIGHMEM
1465 * node_states[N_HIGH_MEMORY] contains nodes which
1466 * have normal memory or high memory.
1467 * Here we add the present_pages belonging to ZONE_HIGHMEM.
1468 * If the zone is within the range of [0..ZONE_HIGHMEM), and
1469 * we determine that the zones in that range become empty,
1470 * we need to clear the node for N_HIGH_MEMORY.
1472 present_pages += pgdat->node_zones[ZONE_HIGHMEM].present_pages;
1473 if (zone_idx(zone) <= ZONE_HIGHMEM && nr_pages >= present_pages)
1474 arg->status_change_nid_high = zone_to_nid(zone);
1478 * We have accounted the pages from [0..ZONE_NORMAL), and
1479 * in case of CONFIG_HIGHMEM the pages from ZONE_HIGHMEM
1481 * Here we count the possible pages from ZONE_MOVABLE.
1482 * If after having accounted all the pages, we see that the nr_pages
1483 * to be offlined is over or equal to the accounted pages,
1484 * we know that the node will become empty, and so, we can clear
1485 * it for N_MEMORY as well.
1487 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
1489 if (nr_pages >= present_pages)
1490 arg->status_change_nid = zone_to_nid(zone);
1493 static void node_states_clear_node(int node, struct memory_notify *arg)
1495 if (arg->status_change_nid_normal >= 0)
1496 node_clear_state(node, N_NORMAL_MEMORY);
1498 if (arg->status_change_nid_high >= 0)
1499 node_clear_state(node, N_HIGH_MEMORY);
1501 if (arg->status_change_nid >= 0)
1502 node_clear_state(node, N_MEMORY);
1505 static int __ref __offline_pages(unsigned long start_pfn,
1506 unsigned long end_pfn)
1508 unsigned long pfn, nr_pages;
1509 unsigned long offlined_pages = 0;
1510 int ret, node, nr_isolate_pageblock;
1511 unsigned long flags;
1512 unsigned long valid_start, valid_end;
1514 struct memory_notify arg;
1517 mem_hotplug_begin();
1519 /* This makes hotplug much easier...and readable.
1520 we assume this for now. .*/
1521 if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start,
1524 reason = "multizone range";
1525 goto failed_removal;
1528 zone = page_zone(pfn_to_page(valid_start));
1529 node = zone_to_nid(zone);
1530 nr_pages = end_pfn - start_pfn;
1532 /* set above range as isolated */
1533 ret = start_isolate_page_range(start_pfn, end_pfn,
1535 SKIP_HWPOISON | REPORT_FAILURE);
1537 reason = "failure to isolate range";
1538 goto failed_removal;
1540 nr_isolate_pageblock = ret;
1542 arg.start_pfn = start_pfn;
1543 arg.nr_pages = nr_pages;
1544 node_states_check_changes_offline(nr_pages, zone, &arg);
1546 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1547 ret = notifier_to_errno(ret);
1549 reason = "notifier failure";
1550 goto failed_removal_isolated;
1554 for (pfn = start_pfn; pfn;) {
1555 if (signal_pending(current)) {
1557 reason = "signal backoff";
1558 goto failed_removal_isolated;
1562 lru_add_drain_all();
1564 pfn = scan_movable_pages(pfn, end_pfn);
1567 * TODO: fatal migration failures should bail
1570 do_migrate_range(pfn, end_pfn);
1575 * Dissolve free hugepages in the memory block before doing
1576 * offlining actually in order to make hugetlbfs's object
1577 * counting consistent.
1579 ret = dissolve_free_huge_pages(start_pfn, end_pfn);
1581 reason = "failure to dissolve huge pages";
1582 goto failed_removal_isolated;
1585 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn,
1586 NULL, check_pages_isolated_cb);
1589 /* Ok, all of our target is isolated.
1590 We cannot do rollback at this point. */
1591 walk_system_ram_range(start_pfn, end_pfn - start_pfn,
1592 &offlined_pages, offline_isolated_pages_cb);
1593 pr_info("Offlined Pages %ld\n", offlined_pages);
1595 * Onlining will reset pagetype flags and makes migrate type
1596 * MOVABLE, so just need to decrease the number of isolated
1597 * pageblocks zone counter here.
1599 spin_lock_irqsave(&zone->lock, flags);
1600 zone->nr_isolate_pageblock -= nr_isolate_pageblock;
1601 spin_unlock_irqrestore(&zone->lock, flags);
1603 /* removal success */
1604 adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
1605 zone->present_pages -= offlined_pages;
1607 pgdat_resize_lock(zone->zone_pgdat, &flags);
1608 zone->zone_pgdat->node_present_pages -= offlined_pages;
1609 pgdat_resize_unlock(zone->zone_pgdat, &flags);
1611 init_per_zone_wmark_min();
1613 if (!populated_zone(zone)) {
1614 zone_pcp_reset(zone);
1615 build_all_zonelists(NULL);
1617 zone_pcp_update(zone);
1619 node_states_clear_node(node, &arg);
1620 if (arg.status_change_nid >= 0) {
1622 kcompactd_stop(node);
1625 vm_total_pages = nr_free_pagecache_pages();
1626 writeback_set_ratelimit();
1628 memory_notify(MEM_OFFLINE, &arg);
1632 failed_removal_isolated:
1633 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1634 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1636 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
1637 (unsigned long long) start_pfn << PAGE_SHIFT,
1638 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
1640 /* pushback to free area */
1645 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1647 return __offline_pages(start_pfn, start_pfn + nr_pages);
1650 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
1652 int ret = !is_memblock_offlined(mem);
1654 if (unlikely(ret)) {
1655 phys_addr_t beginpa, endpa;
1657 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
1658 endpa = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1;
1659 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1667 static int check_cpu_on_node(pg_data_t *pgdat)
1671 for_each_present_cpu(cpu) {
1672 if (cpu_to_node(cpu) == pgdat->node_id)
1674 * the cpu on this node isn't removed, and we can't
1675 * offline this node.
1687 * Offline a node if all memory sections and cpus of the node are removed.
1689 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1690 * and online/offline operations before this call.
1692 void try_offline_node(int nid)
1694 pg_data_t *pgdat = NODE_DATA(nid);
1695 unsigned long start_pfn = pgdat->node_start_pfn;
1696 unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
1699 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1700 unsigned long section_nr = pfn_to_section_nr(pfn);
1702 if (!present_section_nr(section_nr))
1705 if (pfn_to_nid(pfn) != nid)
1709 * some memory sections of this node are not removed, and we
1710 * can't offline node now.
1715 if (check_cpu_on_node(pgdat))
1719 * all memory/cpu of this node are removed, we can offline this
1722 node_set_offline(nid);
1723 unregister_one_node(nid);
1725 EXPORT_SYMBOL(try_offline_node);
1727 static void __release_memory_resource(resource_size_t start,
1728 resource_size_t size)
1733 * When removing memory in the same granularity as it was added,
1734 * this function never fails. It might only fail if resources
1735 * have to be adjusted or split. We'll ignore the error, as
1736 * removing of memory cannot fail.
1738 ret = release_mem_region_adjustable(&iomem_resource, start, size);
1740 resource_size_t endres = start + size - 1;
1742 pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
1743 &start, &endres, ret);
1747 static int __ref try_remove_memory(int nid, u64 start, u64 size)
1751 BUG_ON(check_hotplug_memory_range(start, size));
1753 mem_hotplug_begin();
1756 * All memory blocks must be offlined before removing memory. Check
1757 * whether all memory blocks in question are offline and return error
1758 * if this is not the case.
1760 rc = walk_memory_blocks(start, size, NULL, check_memblock_offlined_cb);
1764 /* remove memmap entry */
1765 firmware_map_remove(start, start + size, "System RAM");
1766 memblock_free(start, size);
1767 memblock_remove(start, size);
1769 /* remove memory block devices before removing memory */
1770 remove_memory_block_devices(start, size);
1772 arch_remove_memory(nid, start, size, NULL);
1773 __release_memory_resource(start, size);
1775 try_offline_node(nid);
1785 * @start: physical address of the region to remove
1786 * @size: size of the region to remove
1788 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1789 * and online/offline operations before this call, as required by
1790 * try_offline_node().
1792 void __remove_memory(int nid, u64 start, u64 size)
1796 * trigger BUG() is some memory is not offlined prior to calling this
1799 if (try_remove_memory(nid, start, size))
1804 * Remove memory if every memory block is offline, otherwise return -EBUSY is
1805 * some memory is not offline
1807 int remove_memory(int nid, u64 start, u64 size)
1811 lock_device_hotplug();
1812 rc = try_remove_memory(nid, start, size);
1813 unlock_device_hotplug();
1817 EXPORT_SYMBOL_GPL(remove_memory);
1818 #endif /* CONFIG_MEMORY_HOTREMOVE */