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/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/cpuset.h>
26 #include <linux/delay.h>
27 #include <linux/migrate.h>
28 #include <linux/page-isolation.h>
30 #include <asm/tlbflush.h>
34 /* add this memory to iomem resource */
35 static struct resource *register_memory_resource(u64 start, u64 size)
38 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
41 res->name = "System RAM";
43 res->end = start + size - 1;
44 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
45 if (request_resource(&iomem_resource, res) < 0) {
46 printk("System RAM resource %llx - %llx cannot be added\n",
47 (unsigned long long)res->start, (unsigned long long)res->end);
54 static void release_memory_resource(struct resource *res)
58 release_resource(res);
63 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
64 #ifndef CONFIG_SPARSEMEM_VMEMMAP
65 static void get_page_bootmem(unsigned long info, struct page *page, int magic)
67 atomic_set(&page->_mapcount, magic);
69 set_page_private(page, info);
70 atomic_inc(&page->_count);
73 void put_page_bootmem(struct page *page)
77 magic = atomic_read(&page->_mapcount);
80 if (atomic_dec_return(&page->_count) == 1) {
81 ClearPagePrivate(page);
82 set_page_private(page, 0);
83 reset_page_mapcount(page);
84 __free_pages_bootmem(page, 0);
89 void register_page_bootmem_info_section(unsigned long start_pfn)
91 unsigned long *usemap, mapsize, section_nr, i;
92 struct mem_section *ms;
93 struct page *page, *memmap;
95 if (!pfn_valid(start_pfn))
98 section_nr = pfn_to_section_nr(start_pfn);
99 ms = __nr_to_section(section_nr);
101 /* Get section's memmap address */
102 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
105 * Get page for the memmap's phys address
106 * XXX: need more consideration for sparse_vmemmap...
108 page = virt_to_page(memmap);
109 mapsize = sizeof(struct page) * PAGES_PER_SECTION;
110 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
112 /* remember memmap's page */
113 for (i = 0; i < mapsize; i++, page++)
114 get_page_bootmem(section_nr, page, SECTION_INFO);
116 usemap = __nr_to_section(section_nr)->pageblock_flags;
117 page = virt_to_page(usemap);
119 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
121 for (i = 0; i < mapsize; i++, page++)
122 get_page_bootmem(section_nr, page, MIX_INFO);
126 void register_page_bootmem_info_node(struct pglist_data *pgdat)
128 unsigned long i, pfn, end_pfn, nr_pages;
129 int node = pgdat->node_id;
133 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
134 page = virt_to_page(pgdat);
136 for (i = 0; i < nr_pages; i++, page++)
137 get_page_bootmem(node, page, NODE_INFO);
139 zone = &pgdat->node_zones[0];
140 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) {
141 if (zone->wait_table) {
142 nr_pages = zone->wait_table_hash_nr_entries
143 * sizeof(wait_queue_head_t);
144 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT;
145 page = virt_to_page(zone->wait_table);
147 for (i = 0; i < nr_pages; i++, page++)
148 get_page_bootmem(node, page, NODE_INFO);
152 pfn = pgdat->node_start_pfn;
153 end_pfn = pfn + pgdat->node_spanned_pages;
155 /* register_section info */
156 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION)
157 register_page_bootmem_info_section(pfn);
160 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
162 static int __add_zone(struct zone *zone, unsigned long phys_start_pfn)
164 struct pglist_data *pgdat = zone->zone_pgdat;
165 int nr_pages = PAGES_PER_SECTION;
166 int nid = pgdat->node_id;
169 zone_type = zone - pgdat->node_zones;
170 if (!zone->wait_table)
171 return init_currently_empty_zone(zone, phys_start_pfn,
172 nr_pages, MEMMAP_HOTPLUG);
173 memmap_init_zone(nr_pages, nid, zone_type,
174 phys_start_pfn, MEMMAP_HOTPLUG);
178 static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
180 int nr_pages = PAGES_PER_SECTION;
183 if (pfn_valid(phys_start_pfn))
186 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
191 ret = __add_zone(zone, phys_start_pfn);
196 return register_new_memory(__pfn_to_section(phys_start_pfn));
199 #ifdef CONFIG_SPARSEMEM_VMEMMAP
200 static int __remove_section(struct zone *zone, struct mem_section *ms)
203 * XXX: Freeing memmap with vmemmap is not implement yet.
204 * This should be removed later.
209 static int __remove_section(struct zone *zone, struct mem_section *ms)
212 struct pglist_data *pgdat = zone->zone_pgdat;
215 if (!valid_section(ms))
218 ret = unregister_memory_section(ms);
222 pgdat_resize_lock(pgdat, &flags);
223 sparse_remove_one_section(zone, ms);
224 pgdat_resize_unlock(pgdat, &flags);
230 * Reasonably generic function for adding memory. It is
231 * expected that archs that support memory hotplug will
232 * call this function after deciding the zone to which to
235 int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
236 unsigned long nr_pages)
240 int start_sec, end_sec;
241 /* during initialize mem_map, align hot-added range to section */
242 start_sec = pfn_to_section_nr(phys_start_pfn);
243 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
245 for (i = start_sec; i <= end_sec; i++) {
246 err = __add_section(zone, i << PFN_SECTION_SHIFT);
249 * EEXIST is finally dealt with by ioresource collision
250 * check. see add_memory() => register_memory_resource()
251 * Warning will be printed if there is collision.
253 if (err && (err != -EEXIST))
260 EXPORT_SYMBOL_GPL(__add_pages);
263 * __remove_pages() - remove sections of pages from a zone
264 * @zone: zone from which pages need to be removed
265 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
266 * @nr_pages: number of pages to remove (must be multiple of section size)
268 * Generic helper function to remove section mappings and sysfs entries
269 * for the section of the memory we are removing. Caller needs to make
270 * sure that pages are marked reserved and zones are adjust properly by
271 * calling offline_pages().
273 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
274 unsigned long nr_pages)
276 unsigned long i, ret = 0;
277 int sections_to_remove;
280 * We can only remove entire sections
282 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
283 BUG_ON(nr_pages % PAGES_PER_SECTION);
285 release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
287 sections_to_remove = nr_pages / PAGES_PER_SECTION;
288 for (i = 0; i < sections_to_remove; i++) {
289 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
290 ret = __remove_section(zone, __pfn_to_section(pfn));
296 EXPORT_SYMBOL_GPL(__remove_pages);
298 static void grow_zone_span(struct zone *zone,
299 unsigned long start_pfn, unsigned long end_pfn)
301 unsigned long old_zone_end_pfn;
303 zone_span_writelock(zone);
305 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
306 if (start_pfn < zone->zone_start_pfn)
307 zone->zone_start_pfn = start_pfn;
309 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
310 zone->zone_start_pfn;
312 zone_span_writeunlock(zone);
315 static void grow_pgdat_span(struct pglist_data *pgdat,
316 unsigned long start_pfn, unsigned long end_pfn)
318 unsigned long old_pgdat_end_pfn =
319 pgdat->node_start_pfn + pgdat->node_spanned_pages;
321 if (start_pfn < pgdat->node_start_pfn)
322 pgdat->node_start_pfn = start_pfn;
324 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
325 pgdat->node_start_pfn;
328 void online_page(struct page *page)
333 #ifdef CONFIG_HIGHMEM
334 if (PageHighMem(page))
338 #ifdef CONFIG_FLATMEM
339 max_mapnr = max(page_to_pfn(page), max_mapnr);
342 ClearPageReserved(page);
343 init_page_count(page);
347 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
351 unsigned long onlined_pages = *(unsigned long *)arg;
353 if (PageReserved(pfn_to_page(start_pfn)))
354 for (i = 0; i < nr_pages; i++) {
355 page = pfn_to_page(start_pfn + i);
359 *(unsigned long *)arg = onlined_pages;
364 int online_pages(unsigned long pfn, unsigned long nr_pages)
367 unsigned long onlined_pages = 0;
369 int need_zonelists_rebuild = 0;
372 struct memory_notify arg;
375 arg.nr_pages = nr_pages;
376 arg.status_change_nid = -1;
378 nid = page_to_nid(pfn_to_page(pfn));
379 if (node_present_pages(nid) == 0)
380 arg.status_change_nid = nid;
382 ret = memory_notify(MEM_GOING_ONLINE, &arg);
383 ret = notifier_to_errno(ret);
385 memory_notify(MEM_CANCEL_ONLINE, &arg);
389 * This doesn't need a lock to do pfn_to_page().
390 * The section can't be removed here because of the
391 * memory_block->state_mutex.
393 zone = page_zone(pfn_to_page(pfn));
394 pgdat_resize_lock(zone->zone_pgdat, &flags);
395 grow_zone_span(zone, pfn, pfn + nr_pages);
396 grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages);
397 pgdat_resize_unlock(zone->zone_pgdat, &flags);
400 * If this zone is not populated, then it is not in zonelist.
401 * This means the page allocator ignores this zone.
402 * So, zonelist must be updated after online.
404 if (!populated_zone(zone))
405 need_zonelists_rebuild = 1;
407 walk_memory_resource(pfn, nr_pages, &onlined_pages,
409 zone->present_pages += onlined_pages;
410 zone->zone_pgdat->node_present_pages += onlined_pages;
412 setup_per_zone_pages_min();
414 kswapd_run(zone_to_nid(zone));
415 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
418 if (need_zonelists_rebuild)
419 build_all_zonelists();
420 vm_total_pages = nr_free_pagecache_pages();
421 writeback_set_ratelimit();
424 memory_notify(MEM_ONLINE, &arg);
428 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
430 static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
432 struct pglist_data *pgdat;
433 unsigned long zones_size[MAX_NR_ZONES] = {0};
434 unsigned long zholes_size[MAX_NR_ZONES] = {0};
435 unsigned long start_pfn = start >> PAGE_SHIFT;
437 pgdat = arch_alloc_nodedata(nid);
441 arch_refresh_nodedata(nid, pgdat);
443 /* we can use NODE_DATA(nid) from here */
445 /* init node's zones as empty zones, we don't have any present pages.*/
446 free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
451 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
453 arch_refresh_nodedata(nid, NULL);
454 arch_free_nodedata(pgdat);
459 int add_memory(int nid, u64 start, u64 size)
461 pg_data_t *pgdat = NULL;
463 struct resource *res;
466 res = register_memory_resource(start, size);
470 if (!node_online(nid)) {
471 pgdat = hotadd_new_pgdat(nid, start);
477 /* call arch's memory hotadd */
478 ret = arch_add_memory(nid, start, size);
483 /* we online node here. we can't roll back from here. */
484 node_set_online(nid);
486 cpuset_track_online_nodes();
489 ret = register_one_node(nid);
491 * If sysfs file of new node can't create, cpu on the node
492 * can't be hot-added. There is no rollback way now.
493 * So, check by BUG_ON() to catch it reluctantly..
500 /* rollback pgdat allocation and others */
502 rollback_node_hotadd(nid, pgdat);
504 release_memory_resource(res);
508 EXPORT_SYMBOL_GPL(add_memory);
510 #ifdef CONFIG_MEMORY_HOTREMOVE
512 * Confirm all pages in a range [start, end) is belongs to the same zone.
514 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
517 struct zone *zone = NULL;
520 for (pfn = start_pfn;
522 pfn += MAX_ORDER_NR_PAGES) {
524 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
525 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
527 if (i == MAX_ORDER_NR_PAGES)
529 page = pfn_to_page(pfn + i);
530 if (zone && page_zone(page) != zone)
532 zone = page_zone(page);
538 * Scanning pfn is much easier than scanning lru list.
539 * Scan pfn from start to end and Find LRU page.
541 int scan_lru_pages(unsigned long start, unsigned long end)
545 for (pfn = start; pfn < end; pfn++) {
546 if (pfn_valid(pfn)) {
547 page = pfn_to_page(pfn);
556 hotremove_migrate_alloc(struct page *page,
557 unsigned long private,
560 /* This should be improoooooved!! */
561 return alloc_page(GFP_HIGHUSER_PAGECACHE);
565 #define NR_OFFLINE_AT_ONCE_PAGES (256)
567 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
571 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
576 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
579 page = pfn_to_page(pfn);
580 if (!page_count(page))
583 * We can skip free pages. And we can only deal with pages on
586 ret = isolate_lru_page(page, &source);
587 if (!ret) { /* Success */
590 /* Becasue we don't have big zone->lock. we should
591 check this again here. */
592 if (page_count(page))
594 #ifdef CONFIG_DEBUG_VM
595 printk(KERN_INFO "removing from LRU failed"
597 pfn, page_count(page), page->flags);
603 if (!list_empty(&source))
604 putback_lru_pages(&source);
608 if (list_empty(&source))
610 /* this function returns # of failed pages */
611 ret = migrate_pages(&source, hotremove_migrate_alloc, 0);
618 * remove from free_area[] and mark all as Reserved.
621 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
624 __offline_isolated_pages(start, start + nr_pages);
629 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
631 walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL,
632 offline_isolated_pages_cb);
636 * Check all pages in range, recoreded as memory resource, are isolated.
639 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
643 long offlined = *(long *)data;
644 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
647 *(long *)data += offlined;
652 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
657 ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined,
658 check_pages_isolated_cb);
660 offlined = (long)ret;
664 int offline_pages(unsigned long start_pfn,
665 unsigned long end_pfn, unsigned long timeout)
667 unsigned long pfn, nr_pages, expire;
669 int ret, drain, retry_max, node;
671 struct memory_notify arg;
673 BUG_ON(start_pfn >= end_pfn);
674 /* at least, alignment against pageblock is necessary */
675 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
677 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
679 /* This makes hotplug much easier...and readable.
680 we assume this for now. .*/
681 if (!test_pages_in_a_zone(start_pfn, end_pfn))
684 zone = page_zone(pfn_to_page(start_pfn));
685 node = zone_to_nid(zone);
686 nr_pages = end_pfn - start_pfn;
688 /* set above range as isolated */
689 ret = start_isolate_page_range(start_pfn, end_pfn);
693 arg.start_pfn = start_pfn;
694 arg.nr_pages = nr_pages;
695 arg.status_change_nid = -1;
696 if (nr_pages >= node_present_pages(node))
697 arg.status_change_nid = node;
699 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
700 ret = notifier_to_errno(ret);
705 expire = jiffies + timeout;
709 /* start memory hot removal */
711 if (time_after(jiffies, expire))
714 if (signal_pending(current))
719 flush_scheduled_work();
724 pfn = scan_lru_pages(start_pfn, end_pfn);
725 if (pfn) { /* We have page on LRU */
726 ret = do_migrate_range(pfn, end_pfn);
732 if (--retry_max == 0)
739 /* drain all zone's lru pagevec, this is asyncronous... */
741 flush_scheduled_work();
743 /* drain pcp pages , this is synchrouns. */
746 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
747 if (offlined_pages < 0) {
751 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
752 /* Ok, all of our target is islaoted.
753 We cannot do rollback at this point. */
754 offline_isolated_pages(start_pfn, end_pfn);
755 /* reset pagetype flags and makes migrate type to be MOVABLE */
756 undo_isolate_page_range(start_pfn, end_pfn);
757 /* removal success */
758 zone->present_pages -= offlined_pages;
759 zone->zone_pgdat->node_present_pages -= offlined_pages;
760 totalram_pages -= offlined_pages;
761 num_physpages -= offlined_pages;
763 vm_total_pages = nr_free_pagecache_pages();
764 writeback_set_ratelimit();
766 memory_notify(MEM_OFFLINE, &arg);
770 printk(KERN_INFO "memory offlining %lx to %lx failed\n",
772 memory_notify(MEM_CANCEL_OFFLINE, &arg);
773 /* pushback to free area */
774 undo_isolate_page_range(start_pfn, end_pfn);
779 int remove_memory(u64 start, u64 size)
783 EXPORT_SYMBOL_GPL(remove_memory);
784 #endif /* CONFIG_MEMORY_HOTREMOVE */