Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / mm / memory_hotplug.c
bloba2acaf820fe518a98a5e6008690967453fbef7d0
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"
37 DEFINE_MUTEX(mem_hotplug_mutex);
39 void lock_memory_hotplug(void)
41 mutex_lock(&mem_hotplug_mutex);
43 /* for exclusive hibernation if CONFIG_HIBERNATION=y */
44 lock_system_sleep();
47 void unlock_memory_hotplug(void)
49 unlock_system_sleep();
50 mutex_unlock(&mem_hotplug_mutex);
54 /* add this memory to iomem resource */
55 static struct resource *register_memory_resource(u64 start, u64 size)
57 struct resource *res;
58 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
59 BUG_ON(!res);
61 res->name = "System RAM";
62 res->start = start;
63 res->end = start + size - 1;
64 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
65 if (request_resource(&iomem_resource, res) < 0) {
66 printk("System RAM resource %llx - %llx cannot be added\n",
67 (unsigned long long)res->start, (unsigned long long)res->end);
68 kfree(res);
69 res = NULL;
71 return res;
74 static void release_memory_resource(struct resource *res)
76 if (!res)
77 return;
78 release_resource(res);
79 kfree(res);
80 return;
83 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
84 #ifndef CONFIG_SPARSEMEM_VMEMMAP
85 static void get_page_bootmem(unsigned long info, struct page *page,
86 unsigned long type)
88 page->lru.next = (struct list_head *) type;
89 SetPagePrivate(page);
90 set_page_private(page, info);
91 atomic_inc(&page->_count);
94 /* reference to __meminit __free_pages_bootmem is valid
95 * so use __ref to tell modpost not to generate a warning */
96 void __ref put_page_bootmem(struct page *page)
98 unsigned long type;
100 type = (unsigned long) page->lru.next;
101 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
102 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
104 if (atomic_dec_return(&page->_count) == 1) {
105 ClearPagePrivate(page);
106 set_page_private(page, 0);
107 INIT_LIST_HEAD(&page->lru);
108 __free_pages_bootmem(page, 0);
113 static void register_page_bootmem_info_section(unsigned long start_pfn)
115 unsigned long *usemap, mapsize, section_nr, i;
116 struct mem_section *ms;
117 struct page *page, *memmap;
119 if (!pfn_valid(start_pfn))
120 return;
122 section_nr = pfn_to_section_nr(start_pfn);
123 ms = __nr_to_section(section_nr);
125 /* Get section's memmap address */
126 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
129 * Get page for the memmap's phys address
130 * XXX: need more consideration for sparse_vmemmap...
132 page = virt_to_page(memmap);
133 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
134 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
136 /* remember memmap's page */
137 for (i = 0; i < mapsize; i++, page++)
138 get_page_bootmem(section_nr, page, SECTION_INFO);
140 usemap = __nr_to_section(section_nr)->pageblock_flags;
141 page = virt_to_page(usemap);
143 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
145 for (i = 0; i < mapsize; i++, page++)
146 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
150 void register_page_bootmem_info_node(struct pglist_data *pgdat)
152 unsigned long i, pfn, end_pfn, nr_pages;
153 int node = pgdat->node_id;
154 struct page *page;
155 struct zone *zone;
157 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
158 page = virt_to_page(pgdat);
160 for (i = 0; i < nr_pages; i++, page++)
161 get_page_bootmem(node, page, NODE_INFO);
163 zone = &pgdat->node_zones[0];
164 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
165 if (zone->wait_table) {
166 nr_pages = zone->wait_table_hash_nr_entries
167 * sizeof(wait_queue_head_t);
168 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
169 page = virt_to_page(zone->wait_table);
171 for (i = 0; i < nr_pages; i++, page++)
172 get_page_bootmem(node, page, NODE_INFO);
176 pfn = pgdat->node_start_pfn;
177 end_pfn = pfn + pgdat->node_spanned_pages;
179 /* register_section info */
180 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION)
181 register_page_bootmem_info_section(pfn);
184 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
186 static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
187 unsigned long end_pfn)
189 unsigned long old_zone_end_pfn;
191 zone_span_writelock(zone);
193 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
194 if (start_pfn < zone->zone_start_pfn)
195 zone->zone_start_pfn = start_pfn;
197 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
198 zone->zone_start_pfn;
200 zone_span_writeunlock(zone);
203 static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
204 unsigned long end_pfn)
206 unsigned long old_pgdat_end_pfn =
207 pgdat->node_start_pfn + pgdat->node_spanned_pages;
209 if (start_pfn < pgdat->node_start_pfn)
210 pgdat->node_start_pfn = start_pfn;
212 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
213 pgdat->node_start_pfn;
216 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
218 struct pglist_data *pgdat = zone->zone_pgdat;
219 int nr_pages = PAGES_PER_SECTION;
220 int nid = pgdat->node_id;
221 int zone_type;
222 unsigned long flags;
224 zone_type = zone - pgdat->node_zones;
225 if (!zone->wait_table) {
226 int ret;
228 ret = init_currently_empty_zone(zone, phys_start_pfn,
229 nr_pages, MEMMAP_HOTPLUG);
230 if (ret)
231 return ret;
233 pgdat_resize_lock(zone->zone_pgdat, &flags);
234 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
235 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
236 phys_start_pfn + nr_pages);
237 pgdat_resize_unlock(zone->zone_pgdat, &flags);
238 memmap_init_zone(nr_pages, nid, zone_type,
239 phys_start_pfn, MEMMAP_HOTPLUG);
240 return 0;
243 static int __meminit __add_section(int nid, struct zone *zone,
244 unsigned long phys_start_pfn)
246 int nr_pages = PAGES_PER_SECTION;
247 int ret;
249 if (pfn_valid(phys_start_pfn))
250 return -EEXIST;
252 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
254 if (ret < 0)
255 return ret;
257 ret = __add_zone(zone, phys_start_pfn);
259 if (ret < 0)
260 return ret;
262 return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
265 #ifdef CONFIG_SPARSEMEM_VMEMMAP
266 static int __remove_section(struct zone *zone, struct mem_section *ms)
269 * XXX: Freeing memmap with vmemmap is not implement yet.
270 * This should be removed later.
272 return -EBUSY;
274 #else
275 static int __remove_section(struct zone *zone, struct mem_section *ms)
277 unsigned long flags;
278 struct pglist_data *pgdat = zone->zone_pgdat;
279 int ret = -EINVAL;
281 if (!valid_section(ms))
282 return ret;
284 ret = unregister_memory_section(ms);
285 if (ret)
286 return ret;
288 pgdat_resize_lock(pgdat, &flags);
289 sparse_remove_one_section(zone, ms);
290 pgdat_resize_unlock(pgdat, &flags);
291 return 0;
293 #endif
296 * Reasonably generic function for adding memory. It is
297 * expected that archs that support memory hotplug will
298 * call this function after deciding the zone to which to
299 * add the new pages.
301 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
302 unsigned long nr_pages)
304 unsigned long i;
305 int err = 0;
306 int start_sec, end_sec;
307 /* during initialize mem_map, align hot-added range to section */
308 start_sec = pfn_to_section_nr(phys_start_pfn);
309 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
311 for (i = start_sec; i <= end_sec; i++) {
312 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
315 * EEXIST is finally dealt with by ioresource collision
316 * check. see add_memory() => register_memory_resource()
317 * Warning will be printed if there is collision.
319 if (err && (err != -EEXIST))
320 break;
321 err = 0;
324 return err;
326 EXPORT_SYMBOL_GPL(__add_pages);
329 * __remove_pages() - remove sections of pages from a zone
330 * @zone: zone from which pages need to be removed
331 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
332 * @nr_pages: number of pages to remove (must be multiple of section size)
334 * Generic helper function to remove section mappings and sysfs entries
335 * for the section of the memory we are removing. Caller needs to make
336 * sure that pages are marked reserved and zones are adjust properly by
337 * calling offline_pages().
339 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
340 unsigned long nr_pages)
342 unsigned long i, ret = 0;
343 int sections_to_remove;
346 * We can only remove entire sections
348 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
349 BUG_ON(nr_pages % PAGES_PER_SECTION);
351 sections_to_remove = nr_pages / PAGES_PER_SECTION;
352 for (i = 0; i < sections_to_remove; i++) {
353 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
354 release_mem_region(pfn << PAGE_SHIFT,
355 PAGES_PER_SECTION << PAGE_SHIFT);
356 ret = __remove_section(zone, __pfn_to_section(pfn));
357 if (ret)
358 break;
360 return ret;
362 EXPORT_SYMBOL_GPL(__remove_pages);
364 void online_page(struct page *page)
366 unsigned long pfn = page_to_pfn(page);
368 totalram_pages++;
369 if (pfn >= num_physpages)
370 num_physpages = pfn + 1;
372 #ifdef CONFIG_HIGHMEM
373 if (PageHighMem(page))
374 totalhigh_pages++;
375 #endif
377 #ifdef CONFIG_FLATMEM
378 max_mapnr = max(page_to_pfn(page), max_mapnr);
379 #endif
381 ClearPageReserved(page);
382 init_page_count(page);
383 __free_page(page);
386 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
387 void *arg)
389 unsigned long i;
390 unsigned long onlined_pages = *(unsigned long *)arg;
391 struct page *page;
392 if (PageReserved(pfn_to_page(start_pfn)))
393 for (i = 0; i < nr_pages; i++) {
394 page = pfn_to_page(start_pfn + i);
395 online_page(page);
396 onlined_pages++;
398 *(unsigned long *)arg = onlined_pages;
399 return 0;
403 int online_pages(unsigned long pfn, unsigned long nr_pages)
405 unsigned long onlined_pages = 0;
406 struct zone *zone;
407 int need_zonelists_rebuild = 0;
408 int nid;
409 int ret;
410 struct memory_notify arg;
412 lock_memory_hotplug();
413 arg.start_pfn = pfn;
414 arg.nr_pages = nr_pages;
415 arg.status_change_nid = -1;
417 nid = page_to_nid(pfn_to_page(pfn));
418 if (node_present_pages(nid) == 0)
419 arg.status_change_nid = nid;
421 ret = memory_notify(MEM_GOING_ONLINE, &arg);
422 ret = notifier_to_errno(ret);
423 if (ret) {
424 memory_notify(MEM_CANCEL_ONLINE, &arg);
425 unlock_memory_hotplug();
426 return ret;
429 * This doesn't need a lock to do pfn_to_page().
430 * The section can't be removed here because of the
431 * memory_block->state_mutex.
433 zone = page_zone(pfn_to_page(pfn));
435 * If this zone is not populated, then it is not in zonelist.
436 * This means the page allocator ignores this zone.
437 * So, zonelist must be updated after online.
439 mutex_lock(&zonelists_mutex);
440 if (!populated_zone(zone))
441 need_zonelists_rebuild = 1;
443 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
444 online_pages_range);
445 if (ret) {
446 mutex_unlock(&zonelists_mutex);
447 printk(KERN_DEBUG "online_pages %lx at %lx failed\n",
448 nr_pages, pfn);
449 memory_notify(MEM_CANCEL_ONLINE, &arg);
450 unlock_memory_hotplug();
451 return ret;
454 zone->present_pages += onlined_pages;
455 zone->zone_pgdat->node_present_pages += onlined_pages;
456 if (need_zonelists_rebuild)
457 build_all_zonelists(zone);
458 else
459 zone_pcp_update(zone);
461 mutex_unlock(&zonelists_mutex);
462 setup_per_zone_wmarks();
463 calculate_zone_inactive_ratio(zone);
464 if (onlined_pages) {
465 kswapd_run(zone_to_nid(zone));
466 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
469 vm_total_pages = nr_free_pagecache_pages();
471 writeback_set_ratelimit();
473 if (onlined_pages)
474 memory_notify(MEM_ONLINE, &arg);
475 unlock_memory_hotplug();
477 return 0;
479 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
481 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
482 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
484 struct pglist_data *pgdat;
485 unsigned long zones_size[MAX_NR_ZONES] = {0};
486 unsigned long zholes_size[MAX_NR_ZONES] = {0};
487 unsigned long start_pfn = start >> PAGE_SHIFT;
489 pgdat = arch_alloc_nodedata(nid);
490 if (!pgdat)
491 return NULL;
493 arch_refresh_nodedata(nid, pgdat);
495 /* we can use NODE_DATA(nid) from here */
497 /* init node's zones as empty zones, we don't have any present pages.*/
498 free_area_init_node(nid, zones_size, start_pfn, zholes_size);
500 return pgdat;
503 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
505 arch_refresh_nodedata(nid, NULL);
506 arch_free_nodedata(pgdat);
507 return;
512 * called by cpu_up() to online a node without onlined memory.
514 int mem_online_node(int nid)
516 pg_data_t *pgdat;
517 int ret;
519 lock_memory_hotplug();
520 pgdat = hotadd_new_pgdat(nid, 0);
521 if (pgdat) {
522 ret = -ENOMEM;
523 goto out;
525 node_set_online(nid);
526 ret = register_one_node(nid);
527 BUG_ON(ret);
529 out:
530 unlock_memory_hotplug();
531 return ret;
534 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
535 int __ref add_memory(int nid, u64 start, u64 size)
537 pg_data_t *pgdat = NULL;
538 int new_pgdat = 0;
539 struct resource *res;
540 int ret;
542 lock_memory_hotplug();
544 res = register_memory_resource(start, size);
545 ret = -EEXIST;
546 if (!res)
547 goto out;
549 if (!node_online(nid)) {
550 pgdat = hotadd_new_pgdat(nid, start);
551 ret = -ENOMEM;
552 if (!pgdat)
553 goto out;
554 new_pgdat = 1;
557 /* call arch's memory hotadd */
558 ret = arch_add_memory(nid, start, size);
560 if (ret < 0)
561 goto error;
563 /* we online node here. we can't roll back from here. */
564 node_set_online(nid);
566 if (new_pgdat) {
567 ret = register_one_node(nid);
569 * If sysfs file of new node can't create, cpu on the node
570 * can't be hot-added. There is no rollback way now.
571 * So, check by BUG_ON() to catch it reluctantly..
573 BUG_ON(ret);
576 /* create new memmap entry */
577 firmware_map_add_hotplug(start, start + size, "System RAM");
579 goto out;
581 error:
582 /* rollback pgdat allocation and others */
583 if (new_pgdat)
584 rollback_node_hotadd(nid, pgdat);
585 if (res)
586 release_memory_resource(res);
588 out:
589 unlock_memory_hotplug();
590 return ret;
592 EXPORT_SYMBOL_GPL(add_memory);
594 #ifdef CONFIG_MEMORY_HOTREMOVE
596 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
597 * set and the size of the free page is given by page_order(). Using this,
598 * the function determines if the pageblock contains only free pages.
599 * Due to buddy contraints, a free page at least the size of a pageblock will
600 * be located at the start of the pageblock
602 static inline int pageblock_free(struct page *page)
604 return PageBuddy(page) && page_order(page) >= pageblock_order;
607 /* Return the start of the next active pageblock after a given page */
608 static struct page *next_active_pageblock(struct page *page)
610 /* Ensure the starting page is pageblock-aligned */
611 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
613 /* If the entire pageblock is free, move to the end of free page */
614 if (pageblock_free(page)) {
615 int order;
616 /* be careful. we don't have locks, page_order can be changed.*/
617 order = page_order(page);
618 if ((order < MAX_ORDER) && (order >= pageblock_order))
619 return page + (1 << order);
622 return page + pageblock_nr_pages;
625 /* Checks if this range of memory is likely to be hot-removable. */
626 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
628 struct page *page = pfn_to_page(start_pfn);
629 struct page *end_page = page + nr_pages;
631 /* Check the starting page of each pageblock within the range */
632 for (; page < end_page; page = next_active_pageblock(page)) {
633 if (!is_pageblock_removable_nolock(page))
634 return 0;
635 cond_resched();
638 /* All pageblocks in the memory block are likely to be hot-removable */
639 return 1;
643 * Confirm all pages in a range [start, end) is belongs to the same zone.
645 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
647 unsigned long pfn;
648 struct zone *zone = NULL;
649 struct page *page;
650 int i;
651 for (pfn = start_pfn;
652 pfn < end_pfn;
653 pfn += MAX_ORDER_NR_PAGES) {
654 i = 0;
655 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
656 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
657 i++;
658 if (i == MAX_ORDER_NR_PAGES)
659 continue;
660 page = pfn_to_page(pfn + i);
661 if (zone && page_zone(page) != zone)
662 return 0;
663 zone = page_zone(page);
665 return 1;
669 * Scanning pfn is much easier than scanning lru list.
670 * Scan pfn from start to end and Find LRU page.
672 static unsigned long scan_lru_pages(unsigned long start, unsigned long end)
674 unsigned long pfn;
675 struct page *page;
676 for (pfn = start; pfn < end; pfn++) {
677 if (pfn_valid(pfn)) {
678 page = pfn_to_page(pfn);
679 if (PageLRU(page))
680 return pfn;
683 return 0;
686 static struct page *
687 hotremove_migrate_alloc(struct page *page, unsigned long private, int **x)
689 /* This should be improooooved!! */
690 return alloc_page(GFP_HIGHUSER_MOVABLE);
693 #define NR_OFFLINE_AT_ONCE_PAGES (256)
694 static int
695 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
697 unsigned long pfn;
698 struct page *page;
699 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
700 int not_managed = 0;
701 int ret = 0;
702 LIST_HEAD(source);
704 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
705 if (!pfn_valid(pfn))
706 continue;
707 page = pfn_to_page(pfn);
708 if (!page_count(page))
709 continue;
711 * We can skip free pages. And we can only deal with pages on
712 * LRU.
714 ret = isolate_lru_page(page);
715 if (!ret) { /* Success */
716 list_add_tail(&page->lru, &source);
717 move_pages--;
718 inc_zone_page_state(page, NR_ISOLATED_ANON +
719 page_is_file_cache(page));
721 } else {
722 #ifdef CONFIG_DEBUG_VM
723 printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
724 pfn);
725 dump_page(page);
726 #endif
727 /* Because we don't have big zone->lock. we should
728 check this again here. */
729 if (page_count(page)) {
730 not_managed++;
731 ret = -EBUSY;
732 break;
736 if (!list_empty(&source)) {
737 if (not_managed) {
738 putback_lru_pages(&source);
739 goto out;
741 /* this function returns # of failed pages */
742 ret = migrate_pages(&source, hotremove_migrate_alloc, 0,
743 true, true);
744 if (ret)
745 putback_lru_pages(&source);
747 out:
748 return ret;
752 * remove from free_area[] and mark all as Reserved.
754 static int
755 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
756 void *data)
758 __offline_isolated_pages(start, start + nr_pages);
759 return 0;
762 static void
763 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
765 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
766 offline_isolated_pages_cb);
770 * Check all pages in range, recoreded as memory resource, are isolated.
772 static int
773 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
774 void *data)
776 int ret;
777 long offlined = *(long *)data;
778 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
779 offlined = nr_pages;
780 if (!ret)
781 *(long *)data += offlined;
782 return ret;
785 static long
786 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
788 long offlined = 0;
789 int ret;
791 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
792 check_pages_isolated_cb);
793 if (ret < 0)
794 offlined = (long)ret;
795 return offlined;
798 static int offline_pages(unsigned long start_pfn,
799 unsigned long end_pfn, unsigned long timeout)
801 unsigned long pfn, nr_pages, expire;
802 long offlined_pages;
803 int ret, drain, retry_max, node;
804 struct zone *zone;
805 struct memory_notify arg;
807 BUG_ON(start_pfn >= end_pfn);
808 /* at least, alignment against pageblock is necessary */
809 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
810 return -EINVAL;
811 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
812 return -EINVAL;
813 /* This makes hotplug much easier...and readable.
814 we assume this for now. .*/
815 if (!test_pages_in_a_zone(start_pfn, end_pfn))
816 return -EINVAL;
818 lock_memory_hotplug();
820 zone = page_zone(pfn_to_page(start_pfn));
821 node = zone_to_nid(zone);
822 nr_pages = end_pfn - start_pfn;
824 /* set above range as isolated */
825 ret = start_isolate_page_range(start_pfn, end_pfn);
826 if (ret)
827 goto out;
829 arg.start_pfn = start_pfn;
830 arg.nr_pages = nr_pages;
831 arg.status_change_nid = -1;
832 if (nr_pages >= node_present_pages(node))
833 arg.status_change_nid = node;
835 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
836 ret = notifier_to_errno(ret);
837 if (ret)
838 goto failed_removal;
840 pfn = start_pfn;
841 expire = jiffies + timeout;
842 drain = 0;
843 retry_max = 5;
844 repeat:
845 /* start memory hot removal */
846 ret = -EAGAIN;
847 if (time_after(jiffies, expire))
848 goto failed_removal;
849 ret = -EINTR;
850 if (signal_pending(current))
851 goto failed_removal;
852 ret = 0;
853 if (drain) {
854 lru_add_drain_all();
855 cond_resched();
856 drain_all_pages();
859 pfn = scan_lru_pages(start_pfn, end_pfn);
860 if (pfn) { /* We have page on LRU */
861 ret = do_migrate_range(pfn, end_pfn);
862 if (!ret) {
863 drain = 1;
864 goto repeat;
865 } else {
866 if (ret < 0)
867 if (--retry_max == 0)
868 goto failed_removal;
869 yield();
870 drain = 1;
871 goto repeat;
874 /* drain all zone's lru pagevec, this is asyncronous... */
875 lru_add_drain_all();
876 yield();
877 /* drain pcp pages , this is synchrouns. */
878 drain_all_pages();
879 /* check again */
880 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
881 if (offlined_pages < 0) {
882 ret = -EBUSY;
883 goto failed_removal;
885 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
886 /* Ok, all of our target is islaoted.
887 We cannot do rollback at this point. */
888 offline_isolated_pages(start_pfn, end_pfn);
889 /* reset pagetype flags and makes migrate type to be MOVABLE */
890 undo_isolate_page_range(start_pfn, end_pfn);
891 /* removal success */
892 zone->present_pages -= offlined_pages;
893 zone->zone_pgdat->node_present_pages -= offlined_pages;
894 totalram_pages -= offlined_pages;
896 setup_per_zone_wmarks();
897 calculate_zone_inactive_ratio(zone);
898 if (!node_present_pages(node)) {
899 node_clear_state(node, N_HIGH_MEMORY);
900 kswapd_stop(node);
903 vm_total_pages = nr_free_pagecache_pages();
904 writeback_set_ratelimit();
906 memory_notify(MEM_OFFLINE, &arg);
907 unlock_memory_hotplug();
908 return 0;
910 failed_removal:
911 printk(KERN_INFO "memory offlining %lx to %lx failed\n",
912 start_pfn, end_pfn);
913 memory_notify(MEM_CANCEL_OFFLINE, &arg);
914 /* pushback to free area */
915 undo_isolate_page_range(start_pfn, end_pfn);
917 out:
918 unlock_memory_hotplug();
919 return ret;
922 int remove_memory(u64 start, u64 size)
924 unsigned long start_pfn, end_pfn;
926 start_pfn = PFN_DOWN(start);
927 end_pfn = start_pfn + PFN_DOWN(size);
928 return offline_pages(start_pfn, end_pfn, 120 * HZ);
930 #else
931 int remove_memory(u64 start, u64 size)
933 return -EINVAL;
935 #endif /* CONFIG_MEMORY_HOTREMOVE */
936 EXPORT_SYMBOL_GPL(remove_memory);