Merge branch 'samsung-fixes-4' of git://github.com/kgene/linux-samsung
[linux-btrfs-devel.git] / mm / memory_hotplug.c
blob6e7d8b21dbfa773d0e3fe116f7e57714713282bc
1 /*
2 * linux/mm/memory_hotplug.c
4 * Copyright (C)
5 */
7 #include <linux/stddef.h>
8 #include <linux/mm.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/module.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>
35 #include "internal.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 */
55 lock_system_sleep();
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)
68 struct resource *res;
69 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
70 BUG_ON(!res);
72 res->name = "System RAM";
73 res->start = start;
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 %llx - %llx cannot be added\n",
78 (unsigned long long)res->start, (unsigned long long)res->end);
79 kfree(res);
80 res = NULL;
82 return res;
85 static void release_memory_resource(struct resource *res)
87 if (!res)
88 return;
89 release_resource(res);
90 kfree(res);
91 return;
94 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
95 #ifndef CONFIG_SPARSEMEM_VMEMMAP
96 static void get_page_bootmem(unsigned long info, struct page *page,
97 unsigned long type)
99 page->lru.next = (struct list_head *) type;
100 SetPagePrivate(page);
101 set_page_private(page, info);
102 atomic_inc(&page->_count);
105 /* reference to __meminit __free_pages_bootmem is valid
106 * so use __ref to tell modpost not to generate a warning */
107 void __ref put_page_bootmem(struct page *page)
109 unsigned long type;
111 type = (unsigned long) page->lru.next;
112 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
113 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
115 if (atomic_dec_return(&page->_count) == 1) {
116 ClearPagePrivate(page);
117 set_page_private(page, 0);
118 INIT_LIST_HEAD(&page->lru);
119 __free_pages_bootmem(page, 0);
124 static void register_page_bootmem_info_section(unsigned long start_pfn)
126 unsigned long *usemap, mapsize, section_nr, i;
127 struct mem_section *ms;
128 struct page *page, *memmap;
130 if (!pfn_valid(start_pfn))
131 return;
133 section_nr = pfn_to_section_nr(start_pfn);
134 ms = __nr_to_section(section_nr);
136 /* Get section's memmap address */
137 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
140 * Get page for the memmap's phys address
141 * XXX: need more consideration for sparse_vmemmap...
143 page = virt_to_page(memmap);
144 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
145 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
147 /* remember memmap's page */
148 for (i = 0; i < mapsize; i++, page++)
149 get_page_bootmem(section_nr, page, SECTION_INFO);
151 usemap = __nr_to_section(section_nr)->pageblock_flags;
152 page = virt_to_page(usemap);
154 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
156 for (i = 0; i < mapsize; i++, page++)
157 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
161 void register_page_bootmem_info_node(struct pglist_data *pgdat)
163 unsigned long i, pfn, end_pfn, nr_pages;
164 int node = pgdat->node_id;
165 struct page *page;
166 struct zone *zone;
168 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
169 page = virt_to_page(pgdat);
171 for (i = 0; i < nr_pages; i++, page++)
172 get_page_bootmem(node, page, NODE_INFO);
174 zone = &pgdat->node_zones[0];
175 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
176 if (zone->wait_table) {
177 nr_pages = zone->wait_table_hash_nr_entries
178 * sizeof(wait_queue_head_t);
179 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
180 page = virt_to_page(zone->wait_table);
182 for (i = 0; i < nr_pages; i++, page++)
183 get_page_bootmem(node, page, NODE_INFO);
187 pfn = pgdat->node_start_pfn;
188 end_pfn = pfn + pgdat->node_spanned_pages;
190 /* register_section info */
191 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION)
192 register_page_bootmem_info_section(pfn);
195 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
197 static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
198 unsigned long end_pfn)
200 unsigned long old_zone_end_pfn;
202 zone_span_writelock(zone);
204 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
205 if (start_pfn < zone->zone_start_pfn)
206 zone->zone_start_pfn = start_pfn;
208 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
209 zone->zone_start_pfn;
211 zone_span_writeunlock(zone);
214 static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
215 unsigned long end_pfn)
217 unsigned long old_pgdat_end_pfn =
218 pgdat->node_start_pfn + pgdat->node_spanned_pages;
220 if (start_pfn < pgdat->node_start_pfn)
221 pgdat->node_start_pfn = start_pfn;
223 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
224 pgdat->node_start_pfn;
227 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
229 struct pglist_data *pgdat = zone->zone_pgdat;
230 int nr_pages = PAGES_PER_SECTION;
231 int nid = pgdat->node_id;
232 int zone_type;
233 unsigned long flags;
235 zone_type = zone - pgdat->node_zones;
236 if (!zone->wait_table) {
237 int ret;
239 ret = init_currently_empty_zone(zone, phys_start_pfn,
240 nr_pages, MEMMAP_HOTPLUG);
241 if (ret)
242 return ret;
244 pgdat_resize_lock(zone->zone_pgdat, &flags);
245 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
246 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
247 phys_start_pfn + nr_pages);
248 pgdat_resize_unlock(zone->zone_pgdat, &flags);
249 memmap_init_zone(nr_pages, nid, zone_type,
250 phys_start_pfn, MEMMAP_HOTPLUG);
251 return 0;
254 static int __meminit __add_section(int nid, struct zone *zone,
255 unsigned long phys_start_pfn)
257 int nr_pages = PAGES_PER_SECTION;
258 int ret;
260 if (pfn_valid(phys_start_pfn))
261 return -EEXIST;
263 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
265 if (ret < 0)
266 return ret;
268 ret = __add_zone(zone, phys_start_pfn);
270 if (ret < 0)
271 return ret;
273 return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
276 #ifdef CONFIG_SPARSEMEM_VMEMMAP
277 static int __remove_section(struct zone *zone, struct mem_section *ms)
280 * XXX: Freeing memmap with vmemmap is not implement yet.
281 * This should be removed later.
283 return -EBUSY;
285 #else
286 static int __remove_section(struct zone *zone, struct mem_section *ms)
288 unsigned long flags;
289 struct pglist_data *pgdat = zone->zone_pgdat;
290 int ret = -EINVAL;
292 if (!valid_section(ms))
293 return ret;
295 ret = unregister_memory_section(ms);
296 if (ret)
297 return ret;
299 pgdat_resize_lock(pgdat, &flags);
300 sparse_remove_one_section(zone, ms);
301 pgdat_resize_unlock(pgdat, &flags);
302 return 0;
304 #endif
307 * Reasonably generic function for adding memory. It is
308 * expected that archs that support memory hotplug will
309 * call this function after deciding the zone to which to
310 * add the new pages.
312 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
313 unsigned long nr_pages)
315 unsigned long i;
316 int err = 0;
317 int start_sec, end_sec;
318 /* during initialize mem_map, align hot-added range to section */
319 start_sec = pfn_to_section_nr(phys_start_pfn);
320 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
322 for (i = start_sec; i <= end_sec; i++) {
323 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
326 * EEXIST is finally dealt with by ioresource collision
327 * check. see add_memory() => register_memory_resource()
328 * Warning will be printed if there is collision.
330 if (err && (err != -EEXIST))
331 break;
332 err = 0;
335 return err;
337 EXPORT_SYMBOL_GPL(__add_pages);
340 * __remove_pages() - remove sections of pages from a zone
341 * @zone: zone from which pages need to be removed
342 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
343 * @nr_pages: number of pages to remove (must be multiple of section size)
345 * Generic helper function to remove section mappings and sysfs entries
346 * for the section of the memory we are removing. Caller needs to make
347 * sure that pages are marked reserved and zones are adjust properly by
348 * calling offline_pages().
350 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
351 unsigned long nr_pages)
353 unsigned long i, ret = 0;
354 int sections_to_remove;
357 * We can only remove entire sections
359 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
360 BUG_ON(nr_pages % PAGES_PER_SECTION);
362 sections_to_remove = nr_pages / PAGES_PER_SECTION;
363 for (i = 0; i < sections_to_remove; i++) {
364 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
365 release_mem_region(pfn << PAGE_SHIFT,
366 PAGES_PER_SECTION << PAGE_SHIFT);
367 ret = __remove_section(zone, __pfn_to_section(pfn));
368 if (ret)
369 break;
371 return ret;
373 EXPORT_SYMBOL_GPL(__remove_pages);
375 int set_online_page_callback(online_page_callback_t callback)
377 int rc = -EINVAL;
379 lock_memory_hotplug();
381 if (online_page_callback == generic_online_page) {
382 online_page_callback = callback;
383 rc = 0;
386 unlock_memory_hotplug();
388 return rc;
390 EXPORT_SYMBOL_GPL(set_online_page_callback);
392 int restore_online_page_callback(online_page_callback_t callback)
394 int rc = -EINVAL;
396 lock_memory_hotplug();
398 if (online_page_callback == callback) {
399 online_page_callback = generic_online_page;
400 rc = 0;
403 unlock_memory_hotplug();
405 return rc;
407 EXPORT_SYMBOL_GPL(restore_online_page_callback);
409 void __online_page_set_limits(struct page *page)
411 unsigned long pfn = page_to_pfn(page);
413 if (pfn >= num_physpages)
414 num_physpages = pfn + 1;
416 EXPORT_SYMBOL_GPL(__online_page_set_limits);
418 void __online_page_increment_counters(struct page *page)
420 totalram_pages++;
422 #ifdef CONFIG_HIGHMEM
423 if (PageHighMem(page))
424 totalhigh_pages++;
425 #endif
427 EXPORT_SYMBOL_GPL(__online_page_increment_counters);
429 void __online_page_free(struct page *page)
431 ClearPageReserved(page);
432 init_page_count(page);
433 __free_page(page);
435 EXPORT_SYMBOL_GPL(__online_page_free);
437 static void generic_online_page(struct page *page)
439 __online_page_set_limits(page);
440 __online_page_increment_counters(page);
441 __online_page_free(page);
444 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
445 void *arg)
447 unsigned long i;
448 unsigned long onlined_pages = *(unsigned long *)arg;
449 struct page *page;
450 if (PageReserved(pfn_to_page(start_pfn)))
451 for (i = 0; i < nr_pages; i++) {
452 page = pfn_to_page(start_pfn + i);
453 (*online_page_callback)(page);
454 onlined_pages++;
456 *(unsigned long *)arg = onlined_pages;
457 return 0;
461 int __ref online_pages(unsigned long pfn, unsigned long nr_pages)
463 unsigned long onlined_pages = 0;
464 struct zone *zone;
465 int need_zonelists_rebuild = 0;
466 int nid;
467 int ret;
468 struct memory_notify arg;
470 lock_memory_hotplug();
471 arg.start_pfn = pfn;
472 arg.nr_pages = nr_pages;
473 arg.status_change_nid = -1;
475 nid = page_to_nid(pfn_to_page(pfn));
476 if (node_present_pages(nid) == 0)
477 arg.status_change_nid = nid;
479 ret = memory_notify(MEM_GOING_ONLINE, &arg);
480 ret = notifier_to_errno(ret);
481 if (ret) {
482 memory_notify(MEM_CANCEL_ONLINE, &arg);
483 unlock_memory_hotplug();
484 return ret;
487 * This doesn't need a lock to do pfn_to_page().
488 * The section can't be removed here because of the
489 * memory_block->state_mutex.
491 zone = page_zone(pfn_to_page(pfn));
493 * If this zone is not populated, then it is not in zonelist.
494 * This means the page allocator ignores this zone.
495 * So, zonelist must be updated after online.
497 mutex_lock(&zonelists_mutex);
498 if (!populated_zone(zone))
499 need_zonelists_rebuild = 1;
501 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
502 online_pages_range);
503 if (ret) {
504 mutex_unlock(&zonelists_mutex);
505 printk(KERN_DEBUG "online_pages %lx at %lx failed\n",
506 nr_pages, pfn);
507 memory_notify(MEM_CANCEL_ONLINE, &arg);
508 unlock_memory_hotplug();
509 return ret;
512 zone->present_pages += onlined_pages;
513 zone->zone_pgdat->node_present_pages += onlined_pages;
514 if (need_zonelists_rebuild)
515 build_all_zonelists(zone);
516 else
517 zone_pcp_update(zone);
519 mutex_unlock(&zonelists_mutex);
521 init_per_zone_wmark_min();
523 if (onlined_pages) {
524 kswapd_run(zone_to_nid(zone));
525 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
528 vm_total_pages = nr_free_pagecache_pages();
530 writeback_set_ratelimit();
532 if (onlined_pages)
533 memory_notify(MEM_ONLINE, &arg);
534 unlock_memory_hotplug();
536 return 0;
538 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
540 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
541 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
543 struct pglist_data *pgdat;
544 unsigned long zones_size[MAX_NR_ZONES] = {0};
545 unsigned long zholes_size[MAX_NR_ZONES] = {0};
546 unsigned long start_pfn = start >> PAGE_SHIFT;
548 pgdat = arch_alloc_nodedata(nid);
549 if (!pgdat)
550 return NULL;
552 arch_refresh_nodedata(nid, pgdat);
554 /* we can use NODE_DATA(nid) from here */
556 /* init node's zones as empty zones, we don't have any present pages.*/
557 free_area_init_node(nid, zones_size, start_pfn, zholes_size);
560 * The node we allocated has no zone fallback lists. For avoiding
561 * to access not-initialized zonelist, build here.
563 mutex_lock(&zonelists_mutex);
564 build_all_zonelists(NULL);
565 mutex_unlock(&zonelists_mutex);
567 return pgdat;
570 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
572 arch_refresh_nodedata(nid, NULL);
573 arch_free_nodedata(pgdat);
574 return;
579 * called by cpu_up() to online a node without onlined memory.
581 int mem_online_node(int nid)
583 pg_data_t *pgdat;
584 int ret;
586 lock_memory_hotplug();
587 pgdat = hotadd_new_pgdat(nid, 0);
588 if (!pgdat) {
589 ret = -ENOMEM;
590 goto out;
592 node_set_online(nid);
593 ret = register_one_node(nid);
594 BUG_ON(ret);
596 out:
597 unlock_memory_hotplug();
598 return ret;
601 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
602 int __ref add_memory(int nid, u64 start, u64 size)
604 pg_data_t *pgdat = NULL;
605 int new_pgdat = 0;
606 struct resource *res;
607 int ret;
609 lock_memory_hotplug();
611 res = register_memory_resource(start, size);
612 ret = -EEXIST;
613 if (!res)
614 goto out;
616 if (!node_online(nid)) {
617 pgdat = hotadd_new_pgdat(nid, start);
618 ret = -ENOMEM;
619 if (!pgdat)
620 goto out;
621 new_pgdat = 1;
624 /* call arch's memory hotadd */
625 ret = arch_add_memory(nid, start, size);
627 if (ret < 0)
628 goto error;
630 /* we online node here. we can't roll back from here. */
631 node_set_online(nid);
633 if (new_pgdat) {
634 ret = register_one_node(nid);
636 * If sysfs file of new node can't create, cpu on the node
637 * can't be hot-added. There is no rollback way now.
638 * So, check by BUG_ON() to catch it reluctantly..
640 BUG_ON(ret);
643 /* create new memmap entry */
644 firmware_map_add_hotplug(start, start + size, "System RAM");
646 goto out;
648 error:
649 /* rollback pgdat allocation and others */
650 if (new_pgdat)
651 rollback_node_hotadd(nid, pgdat);
652 if (res)
653 release_memory_resource(res);
655 out:
656 unlock_memory_hotplug();
657 return ret;
659 EXPORT_SYMBOL_GPL(add_memory);
661 #ifdef CONFIG_MEMORY_HOTREMOVE
663 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
664 * set and the size of the free page is given by page_order(). Using this,
665 * the function determines if the pageblock contains only free pages.
666 * Due to buddy contraints, a free page at least the size of a pageblock will
667 * be located at the start of the pageblock
669 static inline int pageblock_free(struct page *page)
671 return PageBuddy(page) && page_order(page) >= pageblock_order;
674 /* Return the start of the next active pageblock after a given page */
675 static struct page *next_active_pageblock(struct page *page)
677 /* Ensure the starting page is pageblock-aligned */
678 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
680 /* If the entire pageblock is free, move to the end of free page */
681 if (pageblock_free(page)) {
682 int order;
683 /* be careful. we don't have locks, page_order can be changed.*/
684 order = page_order(page);
685 if ((order < MAX_ORDER) && (order >= pageblock_order))
686 return page + (1 << order);
689 return page + pageblock_nr_pages;
692 /* Checks if this range of memory is likely to be hot-removable. */
693 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
695 struct page *page = pfn_to_page(start_pfn);
696 struct page *end_page = page + nr_pages;
698 /* Check the starting page of each pageblock within the range */
699 for (; page < end_page; page = next_active_pageblock(page)) {
700 if (!is_pageblock_removable_nolock(page))
701 return 0;
702 cond_resched();
705 /* All pageblocks in the memory block are likely to be hot-removable */
706 return 1;
710 * Confirm all pages in a range [start, end) is belongs to the same zone.
712 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
714 unsigned long pfn;
715 struct zone *zone = NULL;
716 struct page *page;
717 int i;
718 for (pfn = start_pfn;
719 pfn < end_pfn;
720 pfn += MAX_ORDER_NR_PAGES) {
721 i = 0;
722 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
723 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
724 i++;
725 if (i == MAX_ORDER_NR_PAGES)
726 continue;
727 page = pfn_to_page(pfn + i);
728 if (zone && page_zone(page) != zone)
729 return 0;
730 zone = page_zone(page);
732 return 1;
736 * Scanning pfn is much easier than scanning lru list.
737 * Scan pfn from start to end and Find LRU page.
739 static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
741 unsigned long pfn;
742 struct page *page;
743 for (pfn = start; pfn < end; pfn++) {
744 if (pfn_valid(pfn)) {
745 page = pfn_to_page(pfn);
746 if (PageLRU(page))
747 return pfn;
750 return 0;
753 static struct page *
754 hotremove_migrate_alloc(struct page *page, unsigned long private, int **x)
756 /* This should be improooooved!! */
757 return alloc_page(GFP_HIGHUSER_MOVABLE);
760 #define NR_OFFLINE_AT_ONCE_PAGES (256)
761 static int
762 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
764 unsigned long pfn;
765 struct page *page;
766 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
767 int not_managed = 0;
768 int ret = 0;
769 LIST_HEAD(source);
771 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
772 if (!pfn_valid(pfn))
773 continue;
774 page = pfn_to_page(pfn);
775 if (!get_page_unless_zero(page))
776 continue;
778 * We can skip free pages. And we can only deal with pages on
779 * LRU.
781 ret = isolate_lru_page(page);
782 if (!ret) { /* Success */
783 put_page(page);
784 list_add_tail(&page->lru, &source);
785 move_pages--;
786 inc_zone_page_state(page, NR_ISOLATED_ANON +
787 page_is_file_cache(page));
789 } else {
790 #ifdef CONFIG_DEBUG_VM
791 printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
792 pfn);
793 dump_page(page);
794 #endif
795 put_page(page);
796 /* Because we don't have big zone->lock. we should
797 check this again here. */
798 if (page_count(page)) {
799 not_managed++;
800 ret = -EBUSY;
801 break;
805 if (!list_empty(&source)) {
806 if (not_managed) {
807 putback_lru_pages(&source);
808 goto out;
810 /* this function returns # of failed pages */
811 ret = migrate_pages(&source, hotremove_migrate_alloc, 0,
812 true, true);
813 if (ret)
814 putback_lru_pages(&source);
816 out:
817 return ret;
821 * remove from free_area[] and mark all as Reserved.
823 static int
824 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
825 void *data)
827 __offline_isolated_pages(start, start + nr_pages);
828 return 0;
831 static void
832 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
834 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
835 offline_isolated_pages_cb);
839 * Check all pages in range, recoreded as memory resource, are isolated.
841 static int
842 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
843 void *data)
845 int ret;
846 long offlined = *(long *)data;
847 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
848 offlined = nr_pages;
849 if (!ret)
850 *(long *)data += offlined;
851 return ret;
854 static long
855 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
857 long offlined = 0;
858 int ret;
860 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
861 check_pages_isolated_cb);
862 if (ret < 0)
863 offlined = (long)ret;
864 return offlined;
867 static int __ref offline_pages(unsigned long start_pfn,
868 unsigned long end_pfn, unsigned long timeout)
870 unsigned long pfn, nr_pages, expire;
871 long offlined_pages;
872 int ret, drain, retry_max, node;
873 struct zone *zone;
874 struct memory_notify arg;
876 BUG_ON(start_pfn >= end_pfn);
877 /* at least, alignment against pageblock is necessary */
878 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
879 return -EINVAL;
880 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
881 return -EINVAL;
882 /* This makes hotplug much easier...and readable.
883 we assume this for now. .*/
884 if (!test_pages_in_a_zone(start_pfn, end_pfn))
885 return -EINVAL;
887 lock_memory_hotplug();
889 zone = page_zone(pfn_to_page(start_pfn));
890 node = zone_to_nid(zone);
891 nr_pages = end_pfn - start_pfn;
893 /* set above range as isolated */
894 ret = start_isolate_page_range(start_pfn, end_pfn);
895 if (ret)
896 goto out;
898 arg.start_pfn = start_pfn;
899 arg.nr_pages = nr_pages;
900 arg.status_change_nid = -1;
901 if (nr_pages >= node_present_pages(node))
902 arg.status_change_nid = node;
904 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
905 ret = notifier_to_errno(ret);
906 if (ret)
907 goto failed_removal;
909 pfn = start_pfn;
910 expire = jiffies + timeout;
911 drain = 0;
912 retry_max = 5;
913 repeat:
914 /* start memory hot removal */
915 ret = -EAGAIN;
916 if (time_after(jiffies, expire))
917 goto failed_removal;
918 ret = -EINTR;
919 if (signal_pending(current))
920 goto failed_removal;
921 ret = 0;
922 if (drain) {
923 lru_add_drain_all();
924 cond_resched();
925 drain_all_pages();
928 pfn = scan_lru_pages(start_pfn, end_pfn);
929 if (pfn) { /* We have page on LRU */
930 ret = do_migrate_range(pfn, end_pfn);
931 if (!ret) {
932 drain = 1;
933 goto repeat;
934 } else {
935 if (ret < 0)
936 if (--retry_max == 0)
937 goto failed_removal;
938 yield();
939 drain = 1;
940 goto repeat;
943 /* drain all zone's lru pagevec, this is asyncronous... */
944 lru_add_drain_all();
945 yield();
946 /* drain pcp pages , this is synchrouns. */
947 drain_all_pages();
948 /* check again */
949 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
950 if (offlined_pages < 0) {
951 ret = -EBUSY;
952 goto failed_removal;
954 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
955 /* Ok, all of our target is islaoted.
956 We cannot do rollback at this point. */
957 offline_isolated_pages(start_pfn, end_pfn);
958 /* reset pagetype flags and makes migrate type to be MOVABLE */
959 undo_isolate_page_range(start_pfn, end_pfn);
960 /* removal success */
961 zone->present_pages -= offlined_pages;
962 zone->zone_pgdat->node_present_pages -= offlined_pages;
963 totalram_pages -= offlined_pages;
965 init_per_zone_wmark_min();
967 if (!node_present_pages(node)) {
968 node_clear_state(node, N_HIGH_MEMORY);
969 kswapd_stop(node);
972 vm_total_pages = nr_free_pagecache_pages();
973 writeback_set_ratelimit();
975 memory_notify(MEM_OFFLINE, &arg);
976 unlock_memory_hotplug();
977 return 0;
979 failed_removal:
980 printk(KERN_INFO "memory offlining %lx to %lx failed\n",
981 start_pfn, end_pfn);
982 memory_notify(MEM_CANCEL_OFFLINE, &arg);
983 /* pushback to free area */
984 undo_isolate_page_range(start_pfn, end_pfn);
986 out:
987 unlock_memory_hotplug();
988 return ret;
991 int remove_memory(u64 start, u64 size)
993 unsigned long start_pfn, end_pfn;
995 start_pfn = PFN_DOWN(start);
996 end_pfn = start_pfn + PFN_DOWN(size);
997 return offline_pages(start_pfn, end_pfn, 120 * HZ);
999 #else
1000 int remove_memory(u64 start, u64 size)
1002 return -EINVAL;
1004 #endif /* CONFIG_MEMORY_HOTREMOVE */
1005 EXPORT_SYMBOL_GPL(remove_memory);