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 #ifndef CONFIG_SPARSEMEM_VMEMMAP
95 static void get_page_bootmem(unsigned long info, struct page *page,
98 page->lru.next = (struct list_head *) type;
100 set_page_private(page, info);
101 atomic_inc(&page->_count);
104 /* reference to __meminit __free_pages_bootmem is valid
105 * so use __ref to tell modpost not to generate a warning */
106 void __ref put_page_bootmem(struct page *page)
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);
118 __free_pages_bootmem(page, 0);
123 static void register_page_bootmem_info_section(unsigned long start_pfn)
125 unsigned long *usemap, mapsize, section_nr, i;
126 struct mem_section *ms;
127 struct page *page, *memmap;
129 section_nr = pfn_to_section_nr(start_pfn);
130 ms = __nr_to_section(section_nr);
132 /* Get section's memmap address */
133 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
136 * Get page for the memmap's phys address
137 * XXX: need more consideration for sparse_vmemmap...
139 page = virt_to_page(memmap);
140 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
141 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
143 /* remember memmap's page */
144 for (i = 0; i < mapsize; i++, page++)
145 get_page_bootmem(section_nr, page, SECTION_INFO);
147 usemap = __nr_to_section(section_nr)->pageblock_flags;
148 page = virt_to_page(usemap);
150 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
152 for (i = 0; i < mapsize; i++, page++)
153 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
157 void register_page_bootmem_info_node(struct pglist_data *pgdat)
159 unsigned long i, pfn, end_pfn, nr_pages;
160 int node = pgdat->node_id;
164 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
165 page = virt_to_page(pgdat);
167 for (i = 0; i < nr_pages; i++, page++)
168 get_page_bootmem(node, page, NODE_INFO);
170 zone = &pgdat->node_zones[0];
171 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
172 if (zone->wait_table) {
173 nr_pages = zone->wait_table_hash_nr_entries
174 * sizeof(wait_queue_head_t);
175 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
176 page = virt_to_page(zone->wait_table);
178 for (i = 0; i < nr_pages; i++, page++)
179 get_page_bootmem(node, page, NODE_INFO);
183 pfn = pgdat->node_start_pfn;
184 end_pfn = pfn + pgdat->node_spanned_pages;
186 /* register_section info */
187 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
189 * Some platforms can assign the same pfn to multiple nodes - on
190 * node0 as well as nodeN. To avoid registering a pfn against
191 * multiple nodes we check that this pfn does not already
192 * reside in some other node.
194 if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node))
195 register_page_bootmem_info_section(pfn);
198 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
200 static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
201 unsigned long end_pfn)
203 unsigned long old_zone_end_pfn;
205 zone_span_writelock(zone);
207 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
208 if (!zone->spanned_pages || start_pfn < zone->zone_start_pfn)
209 zone->zone_start_pfn = start_pfn;
211 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
212 zone->zone_start_pfn;
214 zone_span_writeunlock(zone);
217 static void resize_zone(struct zone *zone, unsigned long start_pfn,
218 unsigned long end_pfn)
220 zone_span_writelock(zone);
222 zone->zone_start_pfn = start_pfn;
223 zone->spanned_pages = end_pfn - start_pfn;
225 zone_span_writeunlock(zone);
228 static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
229 unsigned long end_pfn)
231 enum zone_type zid = zone_idx(zone);
232 int nid = zone->zone_pgdat->node_id;
235 for (pfn = start_pfn; pfn < end_pfn; pfn++)
236 set_page_links(pfn_to_page(pfn), zid, nid, pfn);
239 static int move_pfn_range_left(struct zone *z1, struct zone *z2,
240 unsigned long start_pfn, unsigned long end_pfn)
244 pgdat_resize_lock(z1->zone_pgdat, &flags);
246 /* can't move pfns which are higher than @z2 */
247 if (end_pfn > z2->zone_start_pfn + z2->spanned_pages)
249 /* the move out part mast at the left most of @z2 */
250 if (start_pfn > z2->zone_start_pfn)
252 /* must included/overlap */
253 if (end_pfn <= z2->zone_start_pfn)
256 resize_zone(z1, z1->zone_start_pfn, end_pfn);
257 resize_zone(z2, end_pfn, z2->zone_start_pfn + z2->spanned_pages);
259 pgdat_resize_unlock(z1->zone_pgdat, &flags);
261 fix_zone_id(z1, start_pfn, end_pfn);
265 pgdat_resize_unlock(z1->zone_pgdat, &flags);
269 static int move_pfn_range_right(struct zone *z1, struct zone *z2,
270 unsigned long start_pfn, unsigned long end_pfn)
274 pgdat_resize_lock(z1->zone_pgdat, &flags);
276 /* can't move pfns which are lower than @z1 */
277 if (z1->zone_start_pfn > start_pfn)
279 /* the move out part mast at the right most of @z1 */
280 if (z1->zone_start_pfn + z1->spanned_pages > end_pfn)
282 /* must included/overlap */
283 if (start_pfn >= z1->zone_start_pfn + z1->spanned_pages)
286 resize_zone(z1, z1->zone_start_pfn, start_pfn);
287 resize_zone(z2, start_pfn, z2->zone_start_pfn + z2->spanned_pages);
289 pgdat_resize_unlock(z1->zone_pgdat, &flags);
291 fix_zone_id(z2, start_pfn, end_pfn);
295 pgdat_resize_unlock(z1->zone_pgdat, &flags);
299 static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
300 unsigned long end_pfn)
302 unsigned long old_pgdat_end_pfn =
303 pgdat->node_start_pfn + pgdat->node_spanned_pages;
305 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
306 pgdat->node_start_pfn = start_pfn;
308 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
309 pgdat->node_start_pfn;
312 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
314 struct pglist_data *pgdat = zone->zone_pgdat;
315 int nr_pages = PAGES_PER_SECTION;
316 int nid = pgdat->node_id;
320 zone_type = zone - pgdat->node_zones;
321 if (!zone->wait_table) {
324 ret = init_currently_empty_zone(zone, phys_start_pfn,
325 nr_pages, MEMMAP_HOTPLUG);
329 pgdat_resize_lock(zone->zone_pgdat, &flags);
330 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
331 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
332 phys_start_pfn + nr_pages);
333 pgdat_resize_unlock(zone->zone_pgdat, &flags);
334 memmap_init_zone(nr_pages, nid, zone_type,
335 phys_start_pfn, MEMMAP_HOTPLUG);
339 static int __meminit __add_section(int nid, struct zone *zone,
340 unsigned long phys_start_pfn)
342 int nr_pages = PAGES_PER_SECTION;
345 if (pfn_valid(phys_start_pfn))
348 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
353 ret = __add_zone(zone, phys_start_pfn);
358 return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
361 #ifdef CONFIG_SPARSEMEM_VMEMMAP
362 static int __remove_section(struct zone *zone, struct mem_section *ms)
365 * XXX: Freeing memmap with vmemmap is not implement yet.
366 * This should be removed later.
371 static int __remove_section(struct zone *zone, struct mem_section *ms)
374 struct pglist_data *pgdat = zone->zone_pgdat;
377 if (!valid_section(ms))
380 ret = unregister_memory_section(ms);
384 pgdat_resize_lock(pgdat, &flags);
385 sparse_remove_one_section(zone, ms);
386 pgdat_resize_unlock(pgdat, &flags);
392 * Reasonably generic function for adding memory. It is
393 * expected that archs that support memory hotplug will
394 * call this function after deciding the zone to which to
397 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
398 unsigned long nr_pages)
402 int start_sec, end_sec;
403 /* during initialize mem_map, align hot-added range to section */
404 start_sec = pfn_to_section_nr(phys_start_pfn);
405 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
407 for (i = start_sec; i <= end_sec; i++) {
408 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
411 * EEXIST is finally dealt with by ioresource collision
412 * check. see add_memory() => register_memory_resource()
413 * Warning will be printed if there is collision.
415 if (err && (err != -EEXIST))
422 EXPORT_SYMBOL_GPL(__add_pages);
425 * __remove_pages() - remove sections of pages from a zone
426 * @zone: zone from which pages need to be removed
427 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
428 * @nr_pages: number of pages to remove (must be multiple of section size)
430 * Generic helper function to remove section mappings and sysfs entries
431 * for the section of the memory we are removing. Caller needs to make
432 * sure that pages are marked reserved and zones are adjust properly by
433 * calling offline_pages().
435 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
436 unsigned long nr_pages)
438 unsigned long i, ret = 0;
439 int sections_to_remove;
442 * We can only remove entire sections
444 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
445 BUG_ON(nr_pages % PAGES_PER_SECTION);
447 release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
449 sections_to_remove = nr_pages / PAGES_PER_SECTION;
450 for (i = 0; i < sections_to_remove; i++) {
451 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
452 ret = __remove_section(zone, __pfn_to_section(pfn));
458 EXPORT_SYMBOL_GPL(__remove_pages);
460 int set_online_page_callback(online_page_callback_t callback)
464 lock_memory_hotplug();
466 if (online_page_callback == generic_online_page) {
467 online_page_callback = callback;
471 unlock_memory_hotplug();
475 EXPORT_SYMBOL_GPL(set_online_page_callback);
477 int restore_online_page_callback(online_page_callback_t callback)
481 lock_memory_hotplug();
483 if (online_page_callback == callback) {
484 online_page_callback = generic_online_page;
488 unlock_memory_hotplug();
492 EXPORT_SYMBOL_GPL(restore_online_page_callback);
494 void __online_page_set_limits(struct page *page)
496 unsigned long pfn = page_to_pfn(page);
498 if (pfn >= num_physpages)
499 num_physpages = pfn + 1;
501 EXPORT_SYMBOL_GPL(__online_page_set_limits);
503 void __online_page_increment_counters(struct page *page)
507 #ifdef CONFIG_HIGHMEM
508 if (PageHighMem(page))
512 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
514 void __online_page_free(struct page *page)
516 ClearPageReserved(page);
517 init_page_count(page);
520 EXPORT_SYMBOL_GPL(__online_page_free);
522 static void generic_online_page(struct page *page)
524 __online_page_set_limits(page);
525 __online_page_increment_counters(page);
526 __online_page_free(page);
529 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
533 unsigned long onlined_pages = *(unsigned long *)arg;
535 if (PageReserved(pfn_to_page(start_pfn)))
536 for (i = 0; i < nr_pages; i++) {
537 page = pfn_to_page(start_pfn + i);
538 (*online_page_callback)(page);
541 *(unsigned long *)arg = onlined_pages;
545 /* check which state of node_states will be changed when online memory */
546 static void node_states_check_changes_online(unsigned long nr_pages,
547 struct zone *zone, struct memory_notify *arg)
549 int nid = zone_to_nid(zone);
550 enum zone_type zone_last = ZONE_NORMAL;
553 * If we have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes
554 * which have 0...ZONE_NORMAL, set zone_last to ZONE_NORMAL.
556 * If we don't have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes
557 * which have 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
559 if (N_HIGH_MEMORY == N_NORMAL_MEMORY)
560 zone_last = ZONE_MOVABLE;
563 * if the memory to be online is in a zone of 0...zone_last, and
564 * the zones of 0...zone_last don't have memory before online, we will
565 * need to set the node to node_states[N_NORMAL_MEMORY] after
566 * the memory is online.
568 if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
569 arg->status_change_nid_normal = nid;
571 arg->status_change_nid_normal = -1;
574 * if the node don't have memory befor online, we will need to
575 * set the node to node_states[N_HIGH_MEMORY] after the memory
578 if (!node_state(nid, N_HIGH_MEMORY))
579 arg->status_change_nid = nid;
581 arg->status_change_nid = -1;
584 static void node_states_set_node(int node, struct memory_notify *arg)
586 if (arg->status_change_nid_normal >= 0)
587 node_set_state(node, N_NORMAL_MEMORY);
589 node_set_state(node, N_HIGH_MEMORY);
593 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
595 unsigned long onlined_pages = 0;
597 int need_zonelists_rebuild = 0;
600 struct memory_notify arg;
602 lock_memory_hotplug();
604 * This doesn't need a lock to do pfn_to_page().
605 * The section can't be removed here because of the
606 * memory_block->state_mutex.
608 zone = page_zone(pfn_to_page(pfn));
610 if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) {
611 if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) {
612 unlock_memory_hotplug();
616 if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) {
617 if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) {
618 unlock_memory_hotplug();
623 /* Previous code may changed the zone of the pfn range */
624 zone = page_zone(pfn_to_page(pfn));
627 arg.nr_pages = nr_pages;
628 node_states_check_changes_online(nr_pages, zone, &arg);
630 nid = page_to_nid(pfn_to_page(pfn));
632 ret = memory_notify(MEM_GOING_ONLINE, &arg);
633 ret = notifier_to_errno(ret);
635 memory_notify(MEM_CANCEL_ONLINE, &arg);
636 unlock_memory_hotplug();
640 * If this zone is not populated, then it is not in zonelist.
641 * This means the page allocator ignores this zone.
642 * So, zonelist must be updated after online.
644 mutex_lock(&zonelists_mutex);
645 if (!populated_zone(zone)) {
646 need_zonelists_rebuild = 1;
647 build_all_zonelists(NULL, zone);
650 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
653 if (need_zonelists_rebuild)
654 zone_pcp_reset(zone);
655 mutex_unlock(&zonelists_mutex);
656 printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n",
657 (unsigned long long) pfn << PAGE_SHIFT,
658 (((unsigned long long) pfn + nr_pages)
660 memory_notify(MEM_CANCEL_ONLINE, &arg);
661 unlock_memory_hotplug();
665 zone->present_pages += onlined_pages;
666 zone->zone_pgdat->node_present_pages += onlined_pages;
668 node_states_set_node(zone_to_nid(zone), &arg);
669 if (need_zonelists_rebuild)
670 build_all_zonelists(NULL, NULL);
672 zone_pcp_update(zone);
675 mutex_unlock(&zonelists_mutex);
677 init_per_zone_wmark_min();
680 kswapd_run(zone_to_nid(zone));
682 vm_total_pages = nr_free_pagecache_pages();
684 writeback_set_ratelimit();
687 memory_notify(MEM_ONLINE, &arg);
688 unlock_memory_hotplug();
692 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
694 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
695 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
697 struct pglist_data *pgdat;
698 unsigned long zones_size[MAX_NR_ZONES] = {0};
699 unsigned long zholes_size[MAX_NR_ZONES] = {0};
700 unsigned long start_pfn = start >> PAGE_SHIFT;
702 pgdat = arch_alloc_nodedata(nid);
706 arch_refresh_nodedata(nid, pgdat);
708 /* we can use NODE_DATA(nid) from here */
710 /* init node's zones as empty zones, we don't have any present pages.*/
711 free_area_init_node(nid, zones_size, start_pfn, zholes_size);
714 * The node we allocated has no zone fallback lists. For avoiding
715 * to access not-initialized zonelist, build here.
717 mutex_lock(&zonelists_mutex);
718 build_all_zonelists(pgdat, NULL);
719 mutex_unlock(&zonelists_mutex);
724 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
726 arch_refresh_nodedata(nid, NULL);
727 arch_free_nodedata(pgdat);
733 * called by cpu_up() to online a node without onlined memory.
735 int mem_online_node(int nid)
740 lock_memory_hotplug();
741 pgdat = hotadd_new_pgdat(nid, 0);
746 node_set_online(nid);
747 ret = register_one_node(nid);
751 unlock_memory_hotplug();
755 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
756 int __ref add_memory(int nid, u64 start, u64 size)
758 pg_data_t *pgdat = NULL;
760 struct resource *res;
763 lock_memory_hotplug();
765 res = register_memory_resource(start, size);
770 if (!node_online(nid)) {
771 pgdat = hotadd_new_pgdat(nid, start);
778 /* call arch's memory hotadd */
779 ret = arch_add_memory(nid, start, size);
784 /* we online node here. we can't roll back from here. */
785 node_set_online(nid);
788 ret = register_one_node(nid);
790 * If sysfs file of new node can't create, cpu on the node
791 * can't be hot-added. There is no rollback way now.
792 * So, check by BUG_ON() to catch it reluctantly..
797 /* create new memmap entry */
798 firmware_map_add_hotplug(start, start + size, "System RAM");
803 /* rollback pgdat allocation and others */
805 rollback_node_hotadd(nid, pgdat);
807 release_memory_resource(res);
810 unlock_memory_hotplug();
813 EXPORT_SYMBOL_GPL(add_memory);
815 #ifdef CONFIG_MEMORY_HOTREMOVE
817 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
818 * set and the size of the free page is given by page_order(). Using this,
819 * the function determines if the pageblock contains only free pages.
820 * Due to buddy contraints, a free page at least the size of a pageblock will
821 * be located at the start of the pageblock
823 static inline int pageblock_free(struct page *page)
825 return PageBuddy(page) && page_order(page) >= pageblock_order;
828 /* Return the start of the next active pageblock after a given page */
829 static struct page *next_active_pageblock(struct page *page)
831 /* Ensure the starting page is pageblock-aligned */
832 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
834 /* If the entire pageblock is free, move to the end of free page */
835 if (pageblock_free(page)) {
837 /* be careful. we don't have locks, page_order can be changed.*/
838 order = page_order(page);
839 if ((order < MAX_ORDER) && (order >= pageblock_order))
840 return page + (1 << order);
843 return page + pageblock_nr_pages;
846 /* Checks if this range of memory is likely to be hot-removable. */
847 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
849 struct page *page = pfn_to_page(start_pfn);
850 struct page *end_page = page + nr_pages;
852 /* Check the starting page of each pageblock within the range */
853 for (; page < end_page; page = next_active_pageblock(page)) {
854 if (!is_pageblock_removable_nolock(page))
859 /* All pageblocks in the memory block are likely to be hot-removable */
864 * Confirm all pages in a range [start, end) is belongs to the same zone.
866 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
869 struct zone *zone = NULL;
872 for (pfn = start_pfn;
874 pfn += MAX_ORDER_NR_PAGES) {
876 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
877 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
879 if (i == MAX_ORDER_NR_PAGES)
881 page = pfn_to_page(pfn + i);
882 if (zone && page_zone(page) != zone)
884 zone = page_zone(page);
890 * Scanning pfn is much easier than scanning lru list.
891 * Scan pfn from start to end and Find LRU page.
893 static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
897 for (pfn = start; pfn < end; pfn++) {
898 if (pfn_valid(pfn)) {
899 page = pfn_to_page(pfn);
907 #define NR_OFFLINE_AT_ONCE_PAGES (256)
909 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
913 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
918 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
921 page = pfn_to_page(pfn);
922 if (!get_page_unless_zero(page))
925 * We can skip free pages. And we can only deal with pages on
928 ret = isolate_lru_page(page);
929 if (!ret) { /* Success */
931 list_add_tail(&page->lru, &source);
933 inc_zone_page_state(page, NR_ISOLATED_ANON +
934 page_is_file_cache(page));
937 #ifdef CONFIG_DEBUG_VM
938 printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
943 /* Because we don't have big zone->lock. we should
944 check this again here. */
945 if (page_count(page)) {
952 if (!list_empty(&source)) {
954 putback_lru_pages(&source);
959 * alloc_migrate_target should be improooooved!!
960 * migrate_pages returns # of failed pages.
962 ret = migrate_pages(&source, alloc_migrate_target, 0,
965 putback_lru_pages(&source);
972 * remove from free_area[] and mark all as Reserved.
975 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
978 __offline_isolated_pages(start, start + nr_pages);
983 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
985 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
986 offline_isolated_pages_cb);
990 * Check all pages in range, recoreded as memory resource, are isolated.
993 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
997 long offlined = *(long *)data;
998 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1001 *(long *)data += offlined;
1006 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1011 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1012 check_pages_isolated_cb);
1014 offlined = (long)ret;
1018 /* check which state of node_states will be changed when offline memory */
1019 static void node_states_check_changes_offline(unsigned long nr_pages,
1020 struct zone *zone, struct memory_notify *arg)
1022 struct pglist_data *pgdat = zone->zone_pgdat;
1023 unsigned long present_pages = 0;
1024 enum zone_type zt, zone_last = ZONE_NORMAL;
1027 * If we have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes
1028 * which have 0...ZONE_NORMAL, set zone_last to ZONE_NORMAL.
1030 * If we don't have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes
1031 * which have 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1033 if (N_HIGH_MEMORY == N_NORMAL_MEMORY)
1034 zone_last = ZONE_MOVABLE;
1037 * check whether node_states[N_NORMAL_MEMORY] will be changed.
1038 * If the memory to be offline is in a zone of 0...zone_last,
1039 * and it is the last present memory, 0...zone_last will
1040 * become empty after offline , thus we can determind we will
1041 * need to clear the node from node_states[N_NORMAL_MEMORY].
1043 for (zt = 0; zt <= zone_last; zt++)
1044 present_pages += pgdat->node_zones[zt].present_pages;
1045 if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1046 arg->status_change_nid_normal = zone_to_nid(zone);
1048 arg->status_change_nid_normal = -1;
1051 * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1053 zone_last = ZONE_MOVABLE;
1056 * check whether node_states[N_HIGH_MEMORY] will be changed
1057 * If we try to offline the last present @nr_pages from the node,
1058 * we can determind we will need to clear the node from
1059 * node_states[N_HIGH_MEMORY].
1061 for (; zt <= zone_last; zt++)
1062 present_pages += pgdat->node_zones[zt].present_pages;
1063 if (nr_pages >= present_pages)
1064 arg->status_change_nid = zone_to_nid(zone);
1066 arg->status_change_nid = -1;
1069 static void node_states_clear_node(int node, struct memory_notify *arg)
1071 if (arg->status_change_nid_normal >= 0)
1072 node_clear_state(node, N_NORMAL_MEMORY);
1074 if ((N_HIGH_MEMORY != N_NORMAL_MEMORY) &&
1075 (arg->status_change_nid >= 0))
1076 node_clear_state(node, N_HIGH_MEMORY);
1079 static int __ref __offline_pages(unsigned long start_pfn,
1080 unsigned long end_pfn, unsigned long timeout)
1082 unsigned long pfn, nr_pages, expire;
1083 long offlined_pages;
1084 int ret, drain, retry_max, node;
1086 struct memory_notify arg;
1088 BUG_ON(start_pfn >= end_pfn);
1089 /* at least, alignment against pageblock is necessary */
1090 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1092 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1094 /* This makes hotplug much easier...and readable.
1095 we assume this for now. .*/
1096 if (!test_pages_in_a_zone(start_pfn, end_pfn))
1099 lock_memory_hotplug();
1101 zone = page_zone(pfn_to_page(start_pfn));
1102 node = zone_to_nid(zone);
1103 nr_pages = end_pfn - start_pfn;
1105 /* set above range as isolated */
1106 ret = start_isolate_page_range(start_pfn, end_pfn,
1107 MIGRATE_MOVABLE, true);
1111 arg.start_pfn = start_pfn;
1112 arg.nr_pages = nr_pages;
1113 node_states_check_changes_offline(nr_pages, zone, &arg);
1115 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1116 ret = notifier_to_errno(ret);
1118 goto failed_removal;
1121 expire = jiffies + timeout;
1125 /* start memory hot removal */
1127 if (time_after(jiffies, expire))
1128 goto failed_removal;
1130 if (signal_pending(current))
1131 goto failed_removal;
1134 lru_add_drain_all();
1139 pfn = scan_lru_pages(start_pfn, end_pfn);
1140 if (pfn) { /* We have page on LRU */
1141 ret = do_migrate_range(pfn, end_pfn);
1147 if (--retry_max == 0)
1148 goto failed_removal;
1154 /* drain all zone's lru pagevec, this is asyncronous... */
1155 lru_add_drain_all();
1157 /* drain pcp pages , this is synchrouns. */
1160 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1161 if (offlined_pages < 0) {
1163 goto failed_removal;
1165 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
1166 /* Ok, all of our target is islaoted.
1167 We cannot do rollback at this point. */
1168 offline_isolated_pages(start_pfn, end_pfn);
1169 /* reset pagetype flags and makes migrate type to be MOVABLE */
1170 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1171 /* removal success */
1172 zone->present_pages -= offlined_pages;
1173 zone->zone_pgdat->node_present_pages -= offlined_pages;
1174 totalram_pages -= offlined_pages;
1176 init_per_zone_wmark_min();
1178 if (!populated_zone(zone)) {
1179 zone_pcp_reset(zone);
1180 mutex_lock(&zonelists_mutex);
1181 build_all_zonelists(NULL, NULL);
1182 mutex_unlock(&zonelists_mutex);
1184 zone_pcp_update(zone);
1186 node_states_clear_node(node, &arg);
1187 if (arg.status_change_nid >= 0)
1190 vm_total_pages = nr_free_pagecache_pages();
1191 writeback_set_ratelimit();
1193 memory_notify(MEM_OFFLINE, &arg);
1194 unlock_memory_hotplug();
1198 printk(KERN_INFO "memory offlining [mem %#010llx-%#010llx] failed\n",
1199 (unsigned long long) start_pfn << PAGE_SHIFT,
1200 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1201 memory_notify(MEM_CANCEL_OFFLINE, &arg);
1202 /* pushback to free area */
1203 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1206 unlock_memory_hotplug();
1210 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1212 return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
1215 int remove_memory(u64 start, u64 size)
1217 struct memory_block *mem = NULL;
1218 struct mem_section *section;
1219 unsigned long start_pfn, end_pfn;
1220 unsigned long pfn, section_nr;
1223 start_pfn = PFN_DOWN(start);
1224 end_pfn = start_pfn + PFN_DOWN(size);
1226 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1227 section_nr = pfn_to_section_nr(pfn);
1228 if (!present_section_nr(section_nr))
1231 section = __nr_to_section(section_nr);
1232 /* same memblock? */
1234 if ((section_nr >= mem->start_section_nr) &&
1235 (section_nr <= mem->end_section_nr))
1238 mem = find_memory_block_hinted(section, mem);
1242 ret = offline_memory_block(mem);
1244 kobject_put(&mem->dev.kobj);
1250 kobject_put(&mem->dev.kobj);
1255 int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
1259 int remove_memory(u64 start, u64 size)
1263 #endif /* CONFIG_MEMORY_HOTREMOVE */
1264 EXPORT_SYMBOL_GPL(remove_memory);