2 * linux/mm/memory_hotplug.c
7 #include <linux/stddef.h>
9 #include <linux/swap.h>
10 #include <linux/interrupt.h>
11 #include <linux/pagemap.h>
12 #include <linux/bootmem.h>
13 #include <linux/compiler.h>
14 #include <linux/export.h>
15 #include <linux/pagevec.h>
16 #include <linux/writeback.h>
17 #include <linux/slab.h>
18 #include <linux/sysctl.h>
19 #include <linux/cpu.h>
20 #include <linux/memory.h>
21 #include <linux/memory_hotplug.h>
22 #include <linux/highmem.h>
23 #include <linux/vmalloc.h>
24 #include <linux/ioport.h>
25 #include <linux/delay.h>
26 #include <linux/migrate.h>
27 #include <linux/page-isolation.h>
28 #include <linux/pfn.h>
29 #include <linux/suspend.h>
30 #include <linux/mm_inline.h>
31 #include <linux/firmware-map.h>
33 #include <asm/tlbflush.h>
38 * online_page_callback contains pointer to current page onlining function.
39 * Initially it is generic_online_page(). If it is required it could be
40 * changed by calling set_online_page_callback() for callback registration
41 * and restore_online_page_callback() for generic callback restore.
44 static void generic_online_page(struct page *page);
46 static online_page_callback_t online_page_callback = generic_online_page;
48 DEFINE_MUTEX(mem_hotplug_mutex);
50 void lock_memory_hotplug(void)
52 mutex_lock(&mem_hotplug_mutex);
54 /* for exclusive hibernation if CONFIG_HIBERNATION=y */
58 void unlock_memory_hotplug(void)
60 unlock_system_sleep();
61 mutex_unlock(&mem_hotplug_mutex);
65 /* add this memory to iomem resource */
66 static struct resource *register_memory_resource(u64 start, u64 size)
69 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
72 res->name = "System RAM";
74 res->end = start + size - 1;
75 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
76 if (request_resource(&iomem_resource, res) < 0) {
77 printk("System RAM resource %pR cannot be added\n", res);
84 static void release_memory_resource(struct resource *res)
88 release_resource(res);
93 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
94 void get_page_bootmem(unsigned long info, struct page *page,
97 page->lru.next = (struct list_head *) type;
99 set_page_private(page, info);
100 atomic_inc(&page->_count);
103 /* reference to __meminit __free_pages_bootmem is valid
104 * so use __ref to tell modpost not to generate a warning */
105 void __ref put_page_bootmem(struct page *page)
108 static DEFINE_MUTEX(ppb_lock);
110 type = (unsigned long) page->lru.next;
111 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
112 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
114 if (atomic_dec_return(&page->_count) == 1) {
115 ClearPagePrivate(page);
116 set_page_private(page, 0);
117 INIT_LIST_HEAD(&page->lru);
120 * Please refer to comment for __free_pages_bootmem()
121 * for why we serialize here.
123 mutex_lock(&ppb_lock);
124 __free_pages_bootmem(page, 0);
125 mutex_unlock(&ppb_lock);
130 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
131 #ifndef CONFIG_SPARSEMEM_VMEMMAP
132 static void register_page_bootmem_info_section(unsigned long start_pfn)
134 unsigned long *usemap, mapsize, section_nr, i;
135 struct mem_section *ms;
136 struct page *page, *memmap;
138 section_nr = pfn_to_section_nr(start_pfn);
139 ms = __nr_to_section(section_nr);
141 /* Get section's memmap address */
142 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
145 * Get page for the memmap's phys address
146 * XXX: need more consideration for sparse_vmemmap...
148 page = virt_to_page(memmap);
149 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
150 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
152 /* remember memmap's page */
153 for (i = 0; i < mapsize; i++, page++)
154 get_page_bootmem(section_nr, page, SECTION_INFO);
156 usemap = __nr_to_section(section_nr)->pageblock_flags;
157 page = virt_to_page(usemap);
159 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
161 for (i = 0; i < mapsize; i++, page++)
162 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
165 #else /* CONFIG_SPARSEMEM_VMEMMAP */
166 static void register_page_bootmem_info_section(unsigned long start_pfn)
168 unsigned long *usemap, mapsize, section_nr, i;
169 struct mem_section *ms;
170 struct page *page, *memmap;
172 if (!pfn_valid(start_pfn))
175 section_nr = pfn_to_section_nr(start_pfn);
176 ms = __nr_to_section(section_nr);
178 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
180 register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
182 usemap = __nr_to_section(section_nr)->pageblock_flags;
183 page = virt_to_page(usemap);
185 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
187 for (i = 0; i < mapsize; i++, page++)
188 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
190 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
192 void register_page_bootmem_info_node(struct pglist_data *pgdat)
194 unsigned long i, pfn, end_pfn, nr_pages;
195 int node = pgdat->node_id;
199 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
200 page = virt_to_page(pgdat);
202 for (i = 0; i < nr_pages; i++, page++)
203 get_page_bootmem(node, page, NODE_INFO);
205 zone = &pgdat->node_zones[0];
206 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
207 if (zone->wait_table) {
208 nr_pages = zone->wait_table_hash_nr_entries
209 * sizeof(wait_queue_head_t);
210 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
211 page = virt_to_page(zone->wait_table);
213 for (i = 0; i < nr_pages; i++, page++)
214 get_page_bootmem(node, page, NODE_INFO);
218 pfn = pgdat->node_start_pfn;
219 end_pfn = pfn + pgdat->node_spanned_pages;
221 /* register_section info */
222 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
224 * Some platforms can assign the same pfn to multiple nodes - on
225 * node0 as well as nodeN. To avoid registering a pfn against
226 * multiple nodes we check that this pfn does not already
227 * reside in some other node.
229 if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
230 register_page_bootmem_info_section(pfn);
233 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
235 static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
236 unsigned long end_pfn)
238 unsigned long old_zone_end_pfn;
240 zone_span_writelock(zone);
242 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
243 if (!zone->spanned_pages || start_pfn < zone->zone_start_pfn)
244 zone->zone_start_pfn = start_pfn;
246 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
247 zone->zone_start_pfn;
249 zone_span_writeunlock(zone);
252 static void resize_zone(struct zone *zone, unsigned long start_pfn,
253 unsigned long end_pfn)
255 zone_span_writelock(zone);
257 if (end_pfn - start_pfn) {
258 zone->zone_start_pfn = start_pfn;
259 zone->spanned_pages = end_pfn - start_pfn;
262 * make it consist as free_area_init_core(),
263 * if spanned_pages = 0, then keep start_pfn = 0
265 zone->zone_start_pfn = 0;
266 zone->spanned_pages = 0;
269 zone_span_writeunlock(zone);
272 static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
273 unsigned long end_pfn)
275 enum zone_type zid = zone_idx(zone);
276 int nid = zone->zone_pgdat->node_id;
279 for (pfn = start_pfn; pfn < end_pfn; pfn++)
280 set_page_links(pfn_to_page(pfn), zid, nid, pfn);
283 static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
284 unsigned long start_pfn, unsigned long end_pfn)
288 unsigned long z1_start_pfn;
290 if (!z1->wait_table) {
291 ret = init_currently_empty_zone(z1, start_pfn,
292 end_pfn - start_pfn, MEMMAP_HOTPLUG);
297 pgdat_resize_lock(z1->zone_pgdat, &flags);
299 /* can't move pfns which are higher than @z2 */
300 if (end_pfn > z2->zone_start_pfn + z2->spanned_pages)
302 /* the move out part mast at the left most of @z2 */
303 if (start_pfn > z2->zone_start_pfn)
305 /* must included/overlap */
306 if (end_pfn <= z2->zone_start_pfn)
309 /* use start_pfn for z1's start_pfn if z1 is empty */
310 if (z1->spanned_pages)
311 z1_start_pfn = z1->zone_start_pfn;
313 z1_start_pfn = start_pfn;
315 resize_zone(z1, z1_start_pfn, end_pfn);
316 resize_zone(z2, end_pfn, z2->zone_start_pfn + z2->spanned_pages);
318 pgdat_resize_unlock(z1->zone_pgdat, &flags);
320 fix_zone_id(z1, start_pfn, end_pfn);
324 pgdat_resize_unlock(z1->zone_pgdat, &flags);
328 static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
329 unsigned long start_pfn, unsigned long end_pfn)
333 unsigned long z2_end_pfn;
335 if (!z2->wait_table) {
336 ret = init_currently_empty_zone(z2, start_pfn,
337 end_pfn - start_pfn, MEMMAP_HOTPLUG);
342 pgdat_resize_lock(z1->zone_pgdat, &flags);
344 /* can't move pfns which are lower than @z1 */
345 if (z1->zone_start_pfn > start_pfn)
347 /* the move out part mast at the right most of @z1 */
348 if (z1->zone_start_pfn + z1->spanned_pages > end_pfn)
350 /* must included/overlap */
351 if (start_pfn >= z1->zone_start_pfn + z1->spanned_pages)
354 /* use end_pfn for z2's end_pfn if z2 is empty */
355 if (z2->spanned_pages)
356 z2_end_pfn = z2->zone_start_pfn + z2->spanned_pages;
358 z2_end_pfn = end_pfn;
360 resize_zone(z1, z1->zone_start_pfn, start_pfn);
361 resize_zone(z2, start_pfn, z2_end_pfn);
363 pgdat_resize_unlock(z1->zone_pgdat, &flags);
365 fix_zone_id(z2, start_pfn, end_pfn);
369 pgdat_resize_unlock(z1->zone_pgdat, &flags);
373 static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
374 unsigned long end_pfn)
376 unsigned long old_pgdat_end_pfn =
377 pgdat->node_start_pfn + pgdat->node_spanned_pages;
379 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
380 pgdat->node_start_pfn = start_pfn;
382 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
383 pgdat->node_start_pfn;
386 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
388 struct pglist_data *pgdat = zone->zone_pgdat;
389 int nr_pages = PAGES_PER_SECTION;
390 int nid = pgdat->node_id;
394 zone_type = zone - pgdat->node_zones;
395 if (!zone->wait_table) {
398 ret = init_currently_empty_zone(zone, phys_start_pfn,
399 nr_pages, MEMMAP_HOTPLUG);
403 pgdat_resize_lock(zone->zone_pgdat, &flags);
404 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
405 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
406 phys_start_pfn + nr_pages);
407 pgdat_resize_unlock(zone->zone_pgdat, &flags);
408 memmap_init_zone(nr_pages, nid, zone_type,
409 phys_start_pfn, MEMMAP_HOTPLUG);
413 static int __meminit __add_section(int nid, struct zone *zone,
414 unsigned long phys_start_pfn)
416 int nr_pages = PAGES_PER_SECTION;
419 if (pfn_valid(phys_start_pfn))
422 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
427 ret = __add_zone(zone, phys_start_pfn);
432 return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
435 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
436 static int find_smallest_section_pfn(int nid, struct zone *zone,
437 unsigned long start_pfn,
438 unsigned long end_pfn)
440 struct mem_section *ms;
442 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
443 ms = __pfn_to_section(start_pfn);
445 if (unlikely(!valid_section(ms)))
448 if (unlikely(pfn_to_nid(start_pfn) != nid))
451 if (zone && zone != page_zone(pfn_to_page(start_pfn)))
460 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
461 static int find_biggest_section_pfn(int nid, struct zone *zone,
462 unsigned long start_pfn,
463 unsigned long end_pfn)
465 struct mem_section *ms;
468 /* pfn is the end pfn of a memory section. */
470 for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
471 ms = __pfn_to_section(pfn);
473 if (unlikely(!valid_section(ms)))
476 if (unlikely(pfn_to_nid(pfn) != nid))
479 if (zone && zone != page_zone(pfn_to_page(pfn)))
488 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
489 unsigned long end_pfn)
491 unsigned long zone_start_pfn = zone->zone_start_pfn;
492 unsigned long zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
494 struct mem_section *ms;
495 int nid = zone_to_nid(zone);
497 zone_span_writelock(zone);
498 if (zone_start_pfn == start_pfn) {
500 * If the section is smallest section in the zone, it need
501 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
502 * In this case, we find second smallest valid mem_section
503 * for shrinking zone.
505 pfn = find_smallest_section_pfn(nid, zone, end_pfn,
508 zone->zone_start_pfn = pfn;
509 zone->spanned_pages = zone_end_pfn - pfn;
511 } else if (zone_end_pfn == end_pfn) {
513 * If the section is biggest section in the zone, it need
514 * shrink zone->spanned_pages.
515 * In this case, we find second biggest valid mem_section for
518 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
521 zone->spanned_pages = pfn - zone_start_pfn + 1;
525 * The section is not biggest or smallest mem_section in the zone, it
526 * only creates a hole in the zone. So in this case, we need not
527 * change the zone. But perhaps, the zone has only hole data. Thus
528 * it check the zone has only hole or not.
530 pfn = zone_start_pfn;
531 for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
532 ms = __pfn_to_section(pfn);
534 if (unlikely(!valid_section(ms)))
537 if (page_zone(pfn_to_page(pfn)) != zone)
540 /* If the section is current section, it continues the loop */
541 if (start_pfn == pfn)
544 /* If we find valid section, we have nothing to do */
545 zone_span_writeunlock(zone);
549 /* The zone has no valid section */
550 zone->zone_start_pfn = 0;
551 zone->spanned_pages = 0;
552 zone_span_writeunlock(zone);
555 static void shrink_pgdat_span(struct pglist_data *pgdat,
556 unsigned long start_pfn, unsigned long end_pfn)
558 unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
559 unsigned long pgdat_end_pfn =
560 pgdat->node_start_pfn + pgdat->node_spanned_pages;
562 struct mem_section *ms;
563 int nid = pgdat->node_id;
565 if (pgdat_start_pfn == start_pfn) {
567 * If the section is smallest section in the pgdat, it need
568 * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
569 * In this case, we find second smallest valid mem_section
570 * for shrinking zone.
572 pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
575 pgdat->node_start_pfn = pfn;
576 pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
578 } else if (pgdat_end_pfn == end_pfn) {
580 * If the section is biggest section in the pgdat, it need
581 * shrink pgdat->node_spanned_pages.
582 * In this case, we find second biggest valid mem_section for
585 pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
588 pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
592 * If the section is not biggest or smallest mem_section in the pgdat,
593 * it only creates a hole in the pgdat. So in this case, we need not
595 * But perhaps, the pgdat has only hole data. Thus it check the pgdat
596 * has only hole or not.
598 pfn = pgdat_start_pfn;
599 for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
600 ms = __pfn_to_section(pfn);
602 if (unlikely(!valid_section(ms)))
605 if (pfn_to_nid(pfn) != nid)
608 /* If the section is current section, it continues the loop */
609 if (start_pfn == pfn)
612 /* If we find valid section, we have nothing to do */
616 /* The pgdat has no valid section */
617 pgdat->node_start_pfn = 0;
618 pgdat->node_spanned_pages = 0;
621 static void __remove_zone(struct zone *zone, unsigned long start_pfn)
623 struct pglist_data *pgdat = zone->zone_pgdat;
624 int nr_pages = PAGES_PER_SECTION;
628 zone_type = zone - pgdat->node_zones;
630 pgdat_resize_lock(zone->zone_pgdat, &flags);
631 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
632 shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
633 pgdat_resize_unlock(zone->zone_pgdat, &flags);
636 static int __remove_section(struct zone *zone, struct mem_section *ms)
638 unsigned long start_pfn;
642 if (!valid_section(ms))
645 ret = unregister_memory_section(ms);
649 scn_nr = __section_nr(ms);
650 start_pfn = section_nr_to_pfn(scn_nr);
651 __remove_zone(zone, start_pfn);
653 sparse_remove_one_section(zone, ms);
658 * Reasonably generic function for adding memory. It is
659 * expected that archs that support memory hotplug will
660 * call this function after deciding the zone to which to
663 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
664 unsigned long nr_pages)
668 int start_sec, end_sec;
669 /* during initialize mem_map, align hot-added range to section */
670 start_sec = pfn_to_section_nr(phys_start_pfn);
671 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
673 for (i = start_sec; i <= end_sec; i++) {
674 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
677 * EEXIST is finally dealt with by ioresource collision
678 * check. see add_memory() => register_memory_resource()
679 * Warning will be printed if there is collision.
681 if (err && (err != -EEXIST))
688 EXPORT_SYMBOL_GPL(__add_pages);
691 * __remove_pages() - remove sections of pages from a zone
692 * @zone: zone from which pages need to be removed
693 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
694 * @nr_pages: number of pages to remove (must be multiple of section size)
696 * Generic helper function to remove section mappings and sysfs entries
697 * for the section of the memory we are removing. Caller needs to make
698 * sure that pages are marked reserved and zones are adjust properly by
699 * calling offline_pages().
701 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
702 unsigned long nr_pages)
704 unsigned long i, ret = 0;
705 int sections_to_remove;
708 * We can only remove entire sections
710 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
711 BUG_ON(nr_pages % PAGES_PER_SECTION);
713 release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
715 sections_to_remove = nr_pages / PAGES_PER_SECTION;
716 for (i = 0; i < sections_to_remove; i++) {
717 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
718 ret = __remove_section(zone, __pfn_to_section(pfn));
724 EXPORT_SYMBOL_GPL(__remove_pages);
726 int set_online_page_callback(online_page_callback_t callback)
730 lock_memory_hotplug();
732 if (online_page_callback == generic_online_page) {
733 online_page_callback = callback;
737 unlock_memory_hotplug();
741 EXPORT_SYMBOL_GPL(set_online_page_callback);
743 int restore_online_page_callback(online_page_callback_t callback)
747 lock_memory_hotplug();
749 if (online_page_callback == callback) {
750 online_page_callback = generic_online_page;
754 unlock_memory_hotplug();
758 EXPORT_SYMBOL_GPL(restore_online_page_callback);
760 void __online_page_set_limits(struct page *page)
762 unsigned long pfn = page_to_pfn(page);
764 if (pfn >= num_physpages)
765 num_physpages = pfn + 1;
767 EXPORT_SYMBOL_GPL(__online_page_set_limits);
769 void __online_page_increment_counters(struct page *page)
773 #ifdef CONFIG_HIGHMEM
774 if (PageHighMem(page))
778 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
780 void __online_page_free(struct page *page)
782 ClearPageReserved(page);
783 init_page_count(page);
786 EXPORT_SYMBOL_GPL(__online_page_free);
788 static void generic_online_page(struct page *page)
790 __online_page_set_limits(page);
791 __online_page_increment_counters(page);
792 __online_page_free(page);
795 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
799 unsigned long onlined_pages = *(unsigned long *)arg;
801 if (PageReserved(pfn_to_page(start_pfn)))
802 for (i = 0; i < nr_pages; i++) {
803 page = pfn_to_page(start_pfn + i);
804 (*online_page_callback)(page);
807 *(unsigned long *)arg = onlined_pages;
811 #ifdef CONFIG_MOVABLE_NODE
813 * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
816 static bool can_online_high_movable(struct zone *zone)
820 #else /* CONFIG_MOVABLE_NODE */
821 /* ensure every online node has NORMAL memory */
822 static bool can_online_high_movable(struct zone *zone)
824 return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
826 #endif /* CONFIG_MOVABLE_NODE */
828 /* check which state of node_states will be changed when online memory */
829 static void node_states_check_changes_online(unsigned long nr_pages,
830 struct zone *zone, struct memory_notify *arg)
832 int nid = zone_to_nid(zone);
833 enum zone_type zone_last = ZONE_NORMAL;
836 * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
837 * contains nodes which have zones of 0...ZONE_NORMAL,
838 * set zone_last to ZONE_NORMAL.
840 * If we don't have HIGHMEM nor movable node,
841 * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
842 * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
844 if (N_MEMORY == N_NORMAL_MEMORY)
845 zone_last = ZONE_MOVABLE;
848 * if the memory to be online is in a zone of 0...zone_last, and
849 * the zones of 0...zone_last don't have memory before online, we will
850 * need to set the node to node_states[N_NORMAL_MEMORY] after
851 * the memory is online.
853 if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
854 arg->status_change_nid_normal = nid;
856 arg->status_change_nid_normal = -1;
858 #ifdef CONFIG_HIGHMEM
860 * If we have movable node, node_states[N_HIGH_MEMORY]
861 * contains nodes which have zones of 0...ZONE_HIGHMEM,
862 * set zone_last to ZONE_HIGHMEM.
864 * If we don't have movable node, node_states[N_NORMAL_MEMORY]
865 * contains nodes which have zones of 0...ZONE_MOVABLE,
866 * set zone_last to ZONE_MOVABLE.
868 zone_last = ZONE_HIGHMEM;
869 if (N_MEMORY == N_HIGH_MEMORY)
870 zone_last = ZONE_MOVABLE;
872 if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
873 arg->status_change_nid_high = nid;
875 arg->status_change_nid_high = -1;
877 arg->status_change_nid_high = arg->status_change_nid_normal;
881 * if the node don't have memory befor online, we will need to
882 * set the node to node_states[N_MEMORY] after the memory
885 if (!node_state(nid, N_MEMORY))
886 arg->status_change_nid = nid;
888 arg->status_change_nid = -1;
891 static void node_states_set_node(int node, struct memory_notify *arg)
893 if (arg->status_change_nid_normal >= 0)
894 node_set_state(node, N_NORMAL_MEMORY);
896 if (arg->status_change_nid_high >= 0)
897 node_set_state(node, N_HIGH_MEMORY);
899 node_set_state(node, N_MEMORY);
903 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
905 unsigned long onlined_pages = 0;
907 int need_zonelists_rebuild = 0;
910 struct memory_notify arg;
912 lock_memory_hotplug();
914 * This doesn't need a lock to do pfn_to_page().
915 * The section can't be removed here because of the
916 * memory_block->state_mutex.
918 zone = page_zone(pfn_to_page(pfn));
920 if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) &&
921 !can_online_high_movable(zone)) {
922 unlock_memory_hotplug();
926 if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
927 if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
928 unlock_memory_hotplug();
932 if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
933 if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
934 unlock_memory_hotplug();
939 /* Previous code may changed the zone of the pfn range */
940 zone = page_zone(pfn_to_page(pfn));
943 arg.nr_pages = nr_pages;
944 node_states_check_changes_online(nr_pages, zone, &arg);
946 nid = page_to_nid(pfn_to_page(pfn));
948 ret = memory_notify(MEM_GOING_ONLINE, &arg);
949 ret = notifier_to_errno(ret);
951 memory_notify(MEM_CANCEL_ONLINE, &arg);
952 unlock_memory_hotplug();
956 * If this zone is not populated, then it is not in zonelist.
957 * This means the page allocator ignores this zone.
958 * So, zonelist must be updated after online.
960 mutex_lock(&zonelists_mutex);
961 if (!populated_zone(zone)) {
962 need_zonelists_rebuild = 1;
963 build_all_zonelists(NULL, zone);
966 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
969 if (need_zonelists_rebuild)
970 zone_pcp_reset(zone);
971 mutex_unlock(&zonelists_mutex);
972 printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n",
973 (unsigned long long) pfn << PAGE_SHIFT,
974 (((unsigned long long) pfn + nr_pages)
976 memory_notify(MEM_CANCEL_ONLINE, &arg);
977 unlock_memory_hotplug();
981 zone->managed_pages += onlined_pages;
982 zone->present_pages += onlined_pages;
983 zone->zone_pgdat->node_present_pages += onlined_pages;
985 node_states_set_node(zone_to_nid(zone), &arg);
986 if (need_zonelists_rebuild)
987 build_all_zonelists(NULL, NULL);
989 zone_pcp_update(zone);
992 mutex_unlock(&zonelists_mutex);
994 init_per_zone_wmark_min();
997 kswapd_run(zone_to_nid(zone));
999 vm_total_pages = nr_free_pagecache_pages();
1001 writeback_set_ratelimit();
1004 memory_notify(MEM_ONLINE, &arg);
1005 unlock_memory_hotplug();
1009 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
1011 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1012 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
1014 struct pglist_data *pgdat;
1015 unsigned long zones_size[MAX_NR_ZONES] = {0};
1016 unsigned long zholes_size[MAX_NR_ZONES] = {0};
1017 unsigned long start_pfn = start >> PAGE_SHIFT;
1019 pgdat = arch_alloc_nodedata(nid);
1023 arch_refresh_nodedata(nid, pgdat);
1025 /* we can use NODE_DATA(nid) from here */
1027 /* init node's zones as empty zones, we don't have any present pages.*/
1028 free_area_init_node(nid, zones_size, start_pfn, zholes_size);
1031 * The node we allocated has no zone fallback lists. For avoiding
1032 * to access not-initialized zonelist, build here.
1034 mutex_lock(&zonelists_mutex);
1035 build_all_zonelists(pgdat, NULL);
1036 mutex_unlock(&zonelists_mutex);
1041 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
1043 arch_refresh_nodedata(nid, NULL);
1044 arch_free_nodedata(pgdat);
1050 * called by cpu_up() to online a node without onlined memory.
1052 int mem_online_node(int nid)
1057 lock_memory_hotplug();
1058 pgdat = hotadd_new_pgdat(nid, 0);
1063 node_set_online(nid);
1064 ret = register_one_node(nid);
1068 unlock_memory_hotplug();
1072 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1073 int __ref add_memory(int nid, u64 start, u64 size)
1075 pg_data_t *pgdat = NULL;
1077 struct resource *res;
1080 lock_memory_hotplug();
1082 res = register_memory_resource(start, size);
1087 if (!node_online(nid)) {
1088 pgdat = hotadd_new_pgdat(nid, start);
1095 /* call arch's memory hotadd */
1096 ret = arch_add_memory(nid, start, size);
1101 /* we online node here. we can't roll back from here. */
1102 node_set_online(nid);
1105 ret = register_one_node(nid);
1107 * If sysfs file of new node can't create, cpu on the node
1108 * can't be hot-added. There is no rollback way now.
1109 * So, check by BUG_ON() to catch it reluctantly..
1114 /* create new memmap entry */
1115 firmware_map_add_hotplug(start, start + size, "System RAM");
1120 /* rollback pgdat allocation and others */
1122 rollback_node_hotadd(nid, pgdat);
1123 release_memory_resource(res);
1126 unlock_memory_hotplug();
1129 EXPORT_SYMBOL_GPL(add_memory);
1131 #ifdef CONFIG_MEMORY_HOTREMOVE
1133 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1134 * set and the size of the free page is given by page_order(). Using this,
1135 * the function determines if the pageblock contains only free pages.
1136 * Due to buddy contraints, a free page at least the size of a pageblock will
1137 * be located at the start of the pageblock
1139 static inline int pageblock_free(struct page *page)
1141 return PageBuddy(page) && page_order(page) >= pageblock_order;
1144 /* Return the start of the next active pageblock after a given page */
1145 static struct page *next_active_pageblock(struct page *page)
1147 /* Ensure the starting page is pageblock-aligned */
1148 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
1150 /* If the entire pageblock is free, move to the end of free page */
1151 if (pageblock_free(page)) {
1153 /* be careful. we don't have locks, page_order can be changed.*/
1154 order = page_order(page);
1155 if ((order < MAX_ORDER) && (order >= pageblock_order))
1156 return page + (1 << order);
1159 return page + pageblock_nr_pages;
1162 /* Checks if this range of memory is likely to be hot-removable. */
1163 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1165 struct page *page = pfn_to_page(start_pfn);
1166 struct page *end_page = page + nr_pages;
1168 /* Check the starting page of each pageblock within the range */
1169 for (; page < end_page; page = next_active_pageblock(page)) {
1170 if (!is_pageblock_removable_nolock(page))
1175 /* All pageblocks in the memory block are likely to be hot-removable */
1180 * Confirm all pages in a range [start, end) is belongs to the same zone.
1182 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
1185 struct zone *zone = NULL;
1188 for (pfn = start_pfn;
1190 pfn += MAX_ORDER_NR_PAGES) {
1192 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
1193 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
1195 if (i == MAX_ORDER_NR_PAGES)
1197 page = pfn_to_page(pfn + i);
1198 if (zone && page_zone(page) != zone)
1200 zone = page_zone(page);
1206 * Scanning pfn is much easier than scanning lru list.
1207 * Scan pfn from start to end and Find LRU page.
1209 static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
1213 for (pfn = start; pfn < end; pfn++) {
1214 if (pfn_valid(pfn)) {
1215 page = pfn_to_page(pfn);
1223 #define NR_OFFLINE_AT_ONCE_PAGES (256)
1225 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1229 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1230 int not_managed = 0;
1234 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1235 if (!pfn_valid(pfn))
1237 page = pfn_to_page(pfn);
1238 if (!get_page_unless_zero(page))
1241 * We can skip free pages. And we can only deal with pages on
1244 ret = isolate_lru_page(page);
1245 if (!ret) { /* Success */
1247 list_add_tail(&page->lru, &source);
1249 inc_zone_page_state(page, NR_ISOLATED_ANON +
1250 page_is_file_cache(page));
1253 #ifdef CONFIG_DEBUG_VM
1254 printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
1259 /* Because we don't have big zone->lock. we should
1260 check this again here. */
1261 if (page_count(page)) {
1268 if (!list_empty(&source)) {
1270 putback_lru_pages(&source);
1275 * alloc_migrate_target should be improooooved!!
1276 * migrate_pages returns # of failed pages.
1278 ret = migrate_pages(&source, alloc_migrate_target, 0,
1282 putback_lru_pages(&source);
1289 * remove from free_area[] and mark all as Reserved.
1292 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1295 __offline_isolated_pages(start, start + nr_pages);
1300 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1302 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1303 offline_isolated_pages_cb);
1307 * Check all pages in range, recoreded as memory resource, are isolated.
1310 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1314 long offlined = *(long *)data;
1315 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1316 offlined = nr_pages;
1318 *(long *)data += offlined;
1323 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1328 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1329 check_pages_isolated_cb);
1331 offlined = (long)ret;
1335 #ifdef CONFIG_MOVABLE_NODE
1337 * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have
1340 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1344 #else /* CONFIG_MOVABLE_NODE */
1345 /* ensure the node has NORMAL memory if it is still online */
1346 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1348 struct pglist_data *pgdat = zone->zone_pgdat;
1349 unsigned long present_pages = 0;
1352 for (zt = 0; zt <= ZONE_NORMAL; zt++)
1353 present_pages += pgdat->node_zones[zt].present_pages;
1355 if (present_pages > nr_pages)
1359 for (; zt <= ZONE_MOVABLE; zt++)
1360 present_pages += pgdat->node_zones[zt].present_pages;
1363 * we can't offline the last normal memory until all
1364 * higher memory is offlined.
1366 return present_pages == 0;
1368 #endif /* CONFIG_MOVABLE_NODE */
1370 /* check which state of node_states will be changed when offline memory */
1371 static void node_states_check_changes_offline(unsigned long nr_pages,
1372 struct zone *zone, struct memory_notify *arg)
1374 struct pglist_data *pgdat = zone->zone_pgdat;
1375 unsigned long present_pages = 0;
1376 enum zone_type zt, zone_last = ZONE_NORMAL;
1379 * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
1380 * contains nodes which have zones of 0...ZONE_NORMAL,
1381 * set zone_last to ZONE_NORMAL.
1383 * If we don't have HIGHMEM nor movable node,
1384 * node_states[N_NORMAL_MEMORY] contains nodes which have zones of
1385 * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1387 if (N_MEMORY == N_NORMAL_MEMORY)
1388 zone_last = ZONE_MOVABLE;
1391 * check whether node_states[N_NORMAL_MEMORY] will be changed.
1392 * If the memory to be offline is in a zone of 0...zone_last,
1393 * and it is the last present memory, 0...zone_last will
1394 * become empty after offline , thus we can determind we will
1395 * need to clear the node from node_states[N_NORMAL_MEMORY].
1397 for (zt = 0; zt <= zone_last; zt++)
1398 present_pages += pgdat->node_zones[zt].present_pages;
1399 if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1400 arg->status_change_nid_normal = zone_to_nid(zone);
1402 arg->status_change_nid_normal = -1;
1404 #ifdef CONFIG_HIGHMEM
1406 * If we have movable node, node_states[N_HIGH_MEMORY]
1407 * contains nodes which have zones of 0...ZONE_HIGHMEM,
1408 * set zone_last to ZONE_HIGHMEM.
1410 * If we don't have movable node, node_states[N_NORMAL_MEMORY]
1411 * contains nodes which have zones of 0...ZONE_MOVABLE,
1412 * set zone_last to ZONE_MOVABLE.
1414 zone_last = ZONE_HIGHMEM;
1415 if (N_MEMORY == N_HIGH_MEMORY)
1416 zone_last = ZONE_MOVABLE;
1418 for (; zt <= zone_last; zt++)
1419 present_pages += pgdat->node_zones[zt].present_pages;
1420 if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1421 arg->status_change_nid_high = zone_to_nid(zone);
1423 arg->status_change_nid_high = -1;
1425 arg->status_change_nid_high = arg->status_change_nid_normal;
1429 * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1431 zone_last = ZONE_MOVABLE;
1434 * check whether node_states[N_HIGH_MEMORY] will be changed
1435 * If we try to offline the last present @nr_pages from the node,
1436 * we can determind we will need to clear the node from
1437 * node_states[N_HIGH_MEMORY].
1439 for (; zt <= zone_last; zt++)
1440 present_pages += pgdat->node_zones[zt].present_pages;
1441 if (nr_pages >= present_pages)
1442 arg->status_change_nid = zone_to_nid(zone);
1444 arg->status_change_nid = -1;
1447 static void node_states_clear_node(int node, struct memory_notify *arg)
1449 if (arg->status_change_nid_normal >= 0)
1450 node_clear_state(node, N_NORMAL_MEMORY);
1452 if ((N_MEMORY != N_NORMAL_MEMORY) &&
1453 (arg->status_change_nid_high >= 0))
1454 node_clear_state(node, N_HIGH_MEMORY);
1456 if ((N_MEMORY != N_HIGH_MEMORY) &&
1457 (arg->status_change_nid >= 0))
1458 node_clear_state(node, N_MEMORY);
1461 static int __ref __offline_pages(unsigned long start_pfn,
1462 unsigned long end_pfn, unsigned long timeout)
1464 unsigned long pfn, nr_pages, expire;
1465 long offlined_pages;
1466 int ret, drain, retry_max, node;
1468 struct memory_notify arg;
1470 BUG_ON(start_pfn >= end_pfn);
1471 /* at least, alignment against pageblock is necessary */
1472 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1474 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1476 /* This makes hotplug much easier...and readable.
1477 we assume this for now. .*/
1478 if (!test_pages_in_a_zone(start_pfn, end_pfn))
1481 lock_memory_hotplug();
1483 zone = page_zone(pfn_to_page(start_pfn));
1484 node = zone_to_nid(zone);
1485 nr_pages = end_pfn - start_pfn;
1488 if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages))
1491 /* set above range as isolated */
1492 ret = start_isolate_page_range(start_pfn, end_pfn,
1493 MIGRATE_MOVABLE, true);
1497 arg.start_pfn = start_pfn;
1498 arg.nr_pages = nr_pages;
1499 node_states_check_changes_offline(nr_pages, zone, &arg);
1501 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1502 ret = notifier_to_errno(ret);
1504 goto failed_removal;
1507 expire = jiffies + timeout;
1511 /* start memory hot removal */
1513 if (time_after(jiffies, expire))
1514 goto failed_removal;
1516 if (signal_pending(current))
1517 goto failed_removal;
1520 lru_add_drain_all();
1525 pfn = scan_lru_pages(start_pfn, end_pfn);
1526 if (pfn) { /* We have page on LRU */
1527 ret = do_migrate_range(pfn, end_pfn);
1533 if (--retry_max == 0)
1534 goto failed_removal;
1540 /* drain all zone's lru pagevec, this is asynchronous... */
1541 lru_add_drain_all();
1543 /* drain pcp pages, this is synchronous. */
1546 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1547 if (offlined_pages < 0) {
1549 goto failed_removal;
1551 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
1552 /* Ok, all of our target is isolated.
1553 We cannot do rollback at this point. */
1554 offline_isolated_pages(start_pfn, end_pfn);
1555 /* reset pagetype flags and makes migrate type to be MOVABLE */
1556 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1557 /* removal success */
1558 zone->managed_pages -= offlined_pages;
1559 zone->present_pages -= offlined_pages;
1560 zone->zone_pgdat->node_present_pages -= offlined_pages;
1561 totalram_pages -= offlined_pages;
1563 init_per_zone_wmark_min();
1565 if (!populated_zone(zone)) {
1566 zone_pcp_reset(zone);
1567 mutex_lock(&zonelists_mutex);
1568 build_all_zonelists(NULL, NULL);
1569 mutex_unlock(&zonelists_mutex);
1571 zone_pcp_update(zone);
1573 node_states_clear_node(node, &arg);
1574 if (arg.status_change_nid >= 0)
1577 vm_total_pages = nr_free_pagecache_pages();
1578 writeback_set_ratelimit();
1580 memory_notify(MEM_OFFLINE, &arg);
1581 unlock_memory_hotplug();
1585 printk(KERN_INFO "memory offlining [mem %#010llx-%#010llx] failed\n",
1586 (unsigned long long) start_pfn << PAGE_SHIFT,
1587 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1588 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1589 /* pushback to free area */
1590 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1593 unlock_memory_hotplug();
1597 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1599 return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
1603 * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
1604 * @start_pfn: start pfn of the memory range
1605 * @end_pfn: end pft of the memory range
1606 * @arg: argument passed to func
1607 * @func: callback for each memory section walked
1609 * This function walks through all present mem sections in range
1610 * [start_pfn, end_pfn) and call func on each mem section.
1612 * Returns the return value of func.
1614 static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
1615 void *arg, int (*func)(struct memory_block *, void *))
1617 struct memory_block *mem = NULL;
1618 struct mem_section *section;
1619 unsigned long pfn, section_nr;
1622 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1623 section_nr = pfn_to_section_nr(pfn);
1624 if (!present_section_nr(section_nr))
1627 section = __nr_to_section(section_nr);
1628 /* same memblock? */
1630 if ((section_nr >= mem->start_section_nr) &&
1631 (section_nr <= mem->end_section_nr))
1634 mem = find_memory_block_hinted(section, mem);
1638 ret = func(mem, arg);
1640 kobject_put(&mem->dev.kobj);
1646 kobject_put(&mem->dev.kobj);
1652 * offline_memory_block_cb - callback function for offlining memory block
1653 * @mem: the memory block to be offlined
1654 * @arg: buffer to hold error msg
1656 * Always return 0, and put the error msg in arg if any.
1658 static int offline_memory_block_cb(struct memory_block *mem, void *arg)
1661 int error = offline_memory_block(mem);
1663 if (error != 0 && *ret == 0)
1669 static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
1671 int ret = !is_memblock_offlined(mem);
1674 pr_warn("removing memory fails, because memory "
1675 "[%#010llx-%#010llx] is onlined\n",
1676 PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)),
1677 PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1);
1682 int __ref remove_memory(u64 start, u64 size)
1684 unsigned long start_pfn, end_pfn;
1688 start_pfn = PFN_DOWN(start);
1689 end_pfn = start_pfn + PFN_DOWN(size);
1692 * When CONFIG_MEMCG is on, one memory block may be used by other
1693 * blocks to store page cgroup when onlining pages. But we don't know
1694 * in what order pages are onlined. So we iterate twice to offline
1696 * 1st iterate: offline every non primary memory block.
1697 * 2nd iterate: offline primary (i.e. first added) memory block.
1700 walk_memory_range(start_pfn, end_pfn, &ret,
1701 offline_memory_block_cb);
1711 lock_memory_hotplug();
1714 * we have offlined all memory blocks like this:
1715 * 1. lock memory hotplug
1716 * 2. offline a memory block
1717 * 3. unlock memory hotplug
1719 * repeat step1-3 to offline the memory block. All memory blocks
1720 * must be offlined before removing memory. But we don't hold the
1721 * lock in the whole operation. So we should check whether all
1722 * memory blocks are offlined.
1725 ret = walk_memory_range(start_pfn, end_pfn, NULL,
1726 is_memblock_offlined_cb);
1728 unlock_memory_hotplug();
1732 /* remove memmap entry */
1733 firmware_map_remove(start, start + size, "System RAM");
1735 arch_remove_memory(start, size);
1737 unlock_memory_hotplug();
1742 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1746 int remove_memory(u64 start, u64 size)
1750 #endif /* CONFIG_MEMORY_HOTREMOVE */
1751 EXPORT_SYMBOL_GPL(remove_memory);