memory_hotplug.c revision 1e5ad9a3b9b78767a2eb1345201e46f41f9457ef
1/* 2 * linux/mm/memory_hotplug.c 3 * 4 * Copyright (C) 5 */ 6 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/cpuset.h> 26#include <linux/delay.h> 27#include <linux/migrate.h> 28#include <linux/page-isolation.h> 29 30#include <asm/tlbflush.h> 31 32#include "internal.h" 33 34/* add this memory to iomem resource */ 35static struct resource *register_memory_resource(u64 start, u64 size) 36{ 37 struct resource *res; 38 res = kzalloc(sizeof(struct resource), GFP_KERNEL); 39 BUG_ON(!res); 40 41 res->name = "System RAM"; 42 res->start = start; 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); 48 kfree(res); 49 res = NULL; 50 } 51 return res; 52} 53 54static void release_memory_resource(struct resource *res) 55{ 56 if (!res) 57 return; 58 release_resource(res); 59 kfree(res); 60 return; 61} 62 63#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 64#ifndef CONFIG_SPARSEMEM_VMEMMAP 65static void get_page_bootmem(unsigned long info, struct page *page, int magic) 66{ 67 atomic_set(&page->_mapcount, magic); 68 SetPagePrivate(page); 69 set_page_private(page, info); 70 atomic_inc(&page->_count); 71} 72 73void put_page_bootmem(struct page *page) 74{ 75 int magic; 76 77 magic = atomic_read(&page->_mapcount); 78 BUG_ON(magic >= -1); 79 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); 85 } 86 87} 88 89void register_page_bootmem_info_section(unsigned long start_pfn) 90{ 91 unsigned long *usemap, mapsize, section_nr, i; 92 struct mem_section *ms; 93 struct page *page, *memmap; 94 95 if (!pfn_valid(start_pfn)) 96 return; 97 98 section_nr = pfn_to_section_nr(start_pfn); 99 ms = __nr_to_section(section_nr); 100 101 /* Get section's memmap address */ 102 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); 103 104 /* 105 * Get page for the memmap's phys address 106 * XXX: need more consideration for sparse_vmemmap... 107 */ 108 page = virt_to_page(memmap); 109 mapsize = sizeof(struct page) * PAGES_PER_SECTION; 110 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT; 111 112 /* remember memmap's page */ 113 for (i = 0; i < mapsize; i++, page++) 114 get_page_bootmem(section_nr, page, SECTION_INFO); 115 116 usemap = __nr_to_section(section_nr)->pageblock_flags; 117 page = virt_to_page(usemap); 118 119 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; 120 121 for (i = 0; i < mapsize; i++, page++) 122 get_page_bootmem(section_nr, page, MIX_INFO); 123 124} 125 126void register_page_bootmem_info_node(struct pglist_data *pgdat) 127{ 128 unsigned long i, pfn, end_pfn, nr_pages; 129 int node = pgdat->node_id; 130 struct page *page; 131 struct zone *zone; 132 133 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT; 134 page = virt_to_page(pgdat); 135 136 for (i = 0; i < nr_pages; i++, page++) 137 get_page_bootmem(node, page, NODE_INFO); 138 139 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); 146 147 for (i = 0; i < nr_pages; i++, page++) 148 get_page_bootmem(node, page, NODE_INFO); 149 } 150 } 151 152 pfn = pgdat->node_start_pfn; 153 end_pfn = pfn + pgdat->node_spanned_pages; 154 155 /* register_section info */ 156 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) 157 register_page_bootmem_info_section(pfn); 158 159} 160#endif /* !CONFIG_SPARSEMEM_VMEMMAP */ 161 162static int __add_zone(struct zone *zone, unsigned long phys_start_pfn) 163{ 164 struct pglist_data *pgdat = zone->zone_pgdat; 165 int nr_pages = PAGES_PER_SECTION; 166 int nid = pgdat->node_id; 167 int zone_type; 168 169 zone_type = zone - pgdat->node_zones; 170 if (!zone->wait_table) { 171 int ret = 0; 172 ret = init_currently_empty_zone(zone, phys_start_pfn, 173 nr_pages, MEMMAP_HOTPLUG); 174 if (ret < 0) 175 return ret; 176 } 177 memmap_init_zone(nr_pages, nid, zone_type, 178 phys_start_pfn, MEMMAP_HOTPLUG); 179 return 0; 180} 181 182static int __add_section(struct zone *zone, unsigned long phys_start_pfn) 183{ 184 int nr_pages = PAGES_PER_SECTION; 185 int ret; 186 187 if (pfn_valid(phys_start_pfn)) 188 return -EEXIST; 189 190 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); 191 192 if (ret < 0) 193 return ret; 194 195 ret = __add_zone(zone, phys_start_pfn); 196 197 if (ret < 0) 198 return ret; 199 200 return register_new_memory(__pfn_to_section(phys_start_pfn)); 201} 202 203#ifdef CONFIG_SPARSEMEM_VMEMMAP 204static int __remove_section(struct zone *zone, struct mem_section *ms) 205{ 206 /* 207 * XXX: Freeing memmap with vmemmap is not implement yet. 208 * This should be removed later. 209 */ 210 return -EBUSY; 211} 212#else 213static int __remove_section(struct zone *zone, struct mem_section *ms) 214{ 215 unsigned long flags; 216 struct pglist_data *pgdat = zone->zone_pgdat; 217 int ret = -EINVAL; 218 219 if (!valid_section(ms)) 220 return ret; 221 222 ret = unregister_memory_section(ms); 223 if (ret) 224 return ret; 225 226 pgdat_resize_lock(pgdat, &flags); 227 sparse_remove_one_section(zone, ms); 228 pgdat_resize_unlock(pgdat, &flags); 229 return 0; 230} 231#endif 232 233/* 234 * Reasonably generic function for adding memory. It is 235 * expected that archs that support memory hotplug will 236 * call this function after deciding the zone to which to 237 * add the new pages. 238 */ 239int __add_pages(struct zone *zone, unsigned long phys_start_pfn, 240 unsigned long nr_pages) 241{ 242 unsigned long i; 243 int err = 0; 244 int start_sec, end_sec; 245 /* during initialize mem_map, align hot-added range to section */ 246 start_sec = pfn_to_section_nr(phys_start_pfn); 247 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); 248 249 for (i = start_sec; i <= end_sec; i++) { 250 err = __add_section(zone, i << PFN_SECTION_SHIFT); 251 252 /* 253 * EEXIST is finally dealt with by ioresource collision 254 * check. see add_memory() => register_memory_resource() 255 * Warning will be printed if there is collision. 256 */ 257 if (err && (err != -EEXIST)) 258 break; 259 err = 0; 260 } 261 262 return err; 263} 264EXPORT_SYMBOL_GPL(__add_pages); 265 266/** 267 * __remove_pages() - remove sections of pages from a zone 268 * @zone: zone from which pages need to be removed 269 * @phys_start_pfn: starting pageframe (must be aligned to start of a section) 270 * @nr_pages: number of pages to remove (must be multiple of section size) 271 * 272 * Generic helper function to remove section mappings and sysfs entries 273 * for the section of the memory we are removing. Caller needs to make 274 * sure that pages are marked reserved and zones are adjust properly by 275 * calling offline_pages(). 276 */ 277int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, 278 unsigned long nr_pages) 279{ 280 unsigned long i, ret = 0; 281 int sections_to_remove; 282 283 /* 284 * We can only remove entire sections 285 */ 286 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); 287 BUG_ON(nr_pages % PAGES_PER_SECTION); 288 289 release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE); 290 291 sections_to_remove = nr_pages / PAGES_PER_SECTION; 292 for (i = 0; i < sections_to_remove; i++) { 293 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; 294 ret = __remove_section(zone, __pfn_to_section(pfn)); 295 if (ret) 296 break; 297 } 298 return ret; 299} 300EXPORT_SYMBOL_GPL(__remove_pages); 301 302static void grow_zone_span(struct zone *zone, 303 unsigned long start_pfn, unsigned long end_pfn) 304{ 305 unsigned long old_zone_end_pfn; 306 307 zone_span_writelock(zone); 308 309 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; 310 if (start_pfn < zone->zone_start_pfn) 311 zone->zone_start_pfn = start_pfn; 312 313 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - 314 zone->zone_start_pfn; 315 316 zone_span_writeunlock(zone); 317} 318 319static void grow_pgdat_span(struct pglist_data *pgdat, 320 unsigned long start_pfn, unsigned long end_pfn) 321{ 322 unsigned long old_pgdat_end_pfn = 323 pgdat->node_start_pfn + pgdat->node_spanned_pages; 324 325 if (start_pfn < pgdat->node_start_pfn) 326 pgdat->node_start_pfn = start_pfn; 327 328 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - 329 pgdat->node_start_pfn; 330} 331 332void online_page(struct page *page) 333{ 334 totalram_pages++; 335 num_physpages++; 336 337#ifdef CONFIG_HIGHMEM 338 if (PageHighMem(page)) 339 totalhigh_pages++; 340#endif 341 342#ifdef CONFIG_FLATMEM 343 max_mapnr = max(page_to_pfn(page), max_mapnr); 344#endif 345 346 ClearPageReserved(page); 347 init_page_count(page); 348 __free_page(page); 349} 350 351static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, 352 void *arg) 353{ 354 unsigned long i; 355 unsigned long onlined_pages = *(unsigned long *)arg; 356 struct page *page; 357 if (PageReserved(pfn_to_page(start_pfn))) 358 for (i = 0; i < nr_pages; i++) { 359 page = pfn_to_page(start_pfn + i); 360 online_page(page); 361 onlined_pages++; 362 } 363 *(unsigned long *)arg = onlined_pages; 364 return 0; 365} 366 367 368int online_pages(unsigned long pfn, unsigned long nr_pages) 369{ 370 unsigned long flags; 371 unsigned long onlined_pages = 0; 372 struct zone *zone; 373 int need_zonelists_rebuild = 0; 374 int nid; 375 int ret; 376 struct memory_notify arg; 377 378 arg.start_pfn = pfn; 379 arg.nr_pages = nr_pages; 380 arg.status_change_nid = -1; 381 382 nid = page_to_nid(pfn_to_page(pfn)); 383 if (node_present_pages(nid) == 0) 384 arg.status_change_nid = nid; 385 386 ret = memory_notify(MEM_GOING_ONLINE, &arg); 387 ret = notifier_to_errno(ret); 388 if (ret) { 389 memory_notify(MEM_CANCEL_ONLINE, &arg); 390 return ret; 391 } 392 /* 393 * This doesn't need a lock to do pfn_to_page(). 394 * The section can't be removed here because of the 395 * memory_block->state_mutex. 396 */ 397 zone = page_zone(pfn_to_page(pfn)); 398 pgdat_resize_lock(zone->zone_pgdat, &flags); 399 grow_zone_span(zone, pfn, pfn + nr_pages); 400 grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages); 401 pgdat_resize_unlock(zone->zone_pgdat, &flags); 402 403 /* 404 * If this zone is not populated, then it is not in zonelist. 405 * This means the page allocator ignores this zone. 406 * So, zonelist must be updated after online. 407 */ 408 if (!populated_zone(zone)) 409 need_zonelists_rebuild = 1; 410 411 walk_memory_resource(pfn, nr_pages, &onlined_pages, 412 online_pages_range); 413 zone->present_pages += onlined_pages; 414 zone->zone_pgdat->node_present_pages += onlined_pages; 415 416 setup_per_zone_pages_min(); 417 if (onlined_pages) { 418 kswapd_run(zone_to_nid(zone)); 419 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); 420 } 421 422 if (need_zonelists_rebuild) 423 build_all_zonelists(); 424 vm_total_pages = nr_free_pagecache_pages(); 425 writeback_set_ratelimit(); 426 427 if (onlined_pages) 428 memory_notify(MEM_ONLINE, &arg); 429 430 return 0; 431} 432#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 433 434static pg_data_t *hotadd_new_pgdat(int nid, u64 start) 435{ 436 struct pglist_data *pgdat; 437 unsigned long zones_size[MAX_NR_ZONES] = {0}; 438 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 439 unsigned long start_pfn = start >> PAGE_SHIFT; 440 441 pgdat = arch_alloc_nodedata(nid); 442 if (!pgdat) 443 return NULL; 444 445 arch_refresh_nodedata(nid, pgdat); 446 447 /* we can use NODE_DATA(nid) from here */ 448 449 /* init node's zones as empty zones, we don't have any present pages.*/ 450 free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size); 451 452 return pgdat; 453} 454 455static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 456{ 457 arch_refresh_nodedata(nid, NULL); 458 arch_free_nodedata(pgdat); 459 return; 460} 461 462 463int add_memory(int nid, u64 start, u64 size) 464{ 465 pg_data_t *pgdat = NULL; 466 int new_pgdat = 0; 467 struct resource *res; 468 int ret; 469 470 res = register_memory_resource(start, size); 471 if (!res) 472 return -EEXIST; 473 474 if (!node_online(nid)) { 475 pgdat = hotadd_new_pgdat(nid, start); 476 if (!pgdat) 477 return -ENOMEM; 478 new_pgdat = 1; 479 } 480 481 /* call arch's memory hotadd */ 482 ret = arch_add_memory(nid, start, size); 483 484 if (ret < 0) 485 goto error; 486 487 /* we online node here. we can't roll back from here. */ 488 node_set_online(nid); 489 490 cpuset_track_online_nodes(); 491 492 if (new_pgdat) { 493 ret = register_one_node(nid); 494 /* 495 * If sysfs file of new node can't create, cpu on the node 496 * can't be hot-added. There is no rollback way now. 497 * So, check by BUG_ON() to catch it reluctantly.. 498 */ 499 BUG_ON(ret); 500 } 501 502 return ret; 503error: 504 /* rollback pgdat allocation and others */ 505 if (new_pgdat) 506 rollback_node_hotadd(nid, pgdat); 507 if (res) 508 release_memory_resource(res); 509 510 return ret; 511} 512EXPORT_SYMBOL_GPL(add_memory); 513 514#ifdef CONFIG_MEMORY_HOTREMOVE 515/* 516 * Confirm all pages in a range [start, end) is belongs to the same zone. 517 */ 518static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 519{ 520 unsigned long pfn; 521 struct zone *zone = NULL; 522 struct page *page; 523 int i; 524 for (pfn = start_pfn; 525 pfn < end_pfn; 526 pfn += MAX_ORDER_NR_PAGES) { 527 i = 0; 528 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 529 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 530 i++; 531 if (i == MAX_ORDER_NR_PAGES) 532 continue; 533 page = pfn_to_page(pfn + i); 534 if (zone && page_zone(page) != zone) 535 return 0; 536 zone = page_zone(page); 537 } 538 return 1; 539} 540 541/* 542 * Scanning pfn is much easier than scanning lru list. 543 * Scan pfn from start to end and Find LRU page. 544 */ 545int scan_lru_pages(unsigned long start, unsigned long end) 546{ 547 unsigned long pfn; 548 struct page *page; 549 for (pfn = start; pfn < end; pfn++) { 550 if (pfn_valid(pfn)) { 551 page = pfn_to_page(pfn); 552 if (PageLRU(page)) 553 return pfn; 554 } 555 } 556 return 0; 557} 558 559static struct page * 560hotremove_migrate_alloc(struct page *page, 561 unsigned long private, 562 int **x) 563{ 564 /* This should be improoooooved!! */ 565 return alloc_page(GFP_HIGHUSER_PAGECACHE); 566} 567 568 569#define NR_OFFLINE_AT_ONCE_PAGES (256) 570static int 571do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 572{ 573 unsigned long pfn; 574 struct page *page; 575 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 576 int not_managed = 0; 577 int ret = 0; 578 LIST_HEAD(source); 579 580 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 581 if (!pfn_valid(pfn)) 582 continue; 583 page = pfn_to_page(pfn); 584 if (!page_count(page)) 585 continue; 586 /* 587 * We can skip free pages. And we can only deal with pages on 588 * LRU. 589 */ 590 ret = isolate_lru_page(page, &source); 591 if (!ret) { /* Success */ 592 move_pages--; 593 } else { 594 /* Becasue we don't have big zone->lock. we should 595 check this again here. */ 596 if (page_count(page)) 597 not_managed++; 598#ifdef CONFIG_DEBUG_VM 599 printk(KERN_INFO "removing from LRU failed" 600 " %lx/%d/%lx\n", 601 pfn, page_count(page), page->flags); 602#endif 603 } 604 } 605 ret = -EBUSY; 606 if (not_managed) { 607 if (!list_empty(&source)) 608 putback_lru_pages(&source); 609 goto out; 610 } 611 ret = 0; 612 if (list_empty(&source)) 613 goto out; 614 /* this function returns # of failed pages */ 615 ret = migrate_pages(&source, hotremove_migrate_alloc, 0); 616 617out: 618 return ret; 619} 620 621/* 622 * remove from free_area[] and mark all as Reserved. 623 */ 624static int 625offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 626 void *data) 627{ 628 __offline_isolated_pages(start, start + nr_pages); 629 return 0; 630} 631 632static void 633offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 634{ 635 walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL, 636 offline_isolated_pages_cb); 637} 638 639/* 640 * Check all pages in range, recoreded as memory resource, are isolated. 641 */ 642static int 643check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 644 void *data) 645{ 646 int ret; 647 long offlined = *(long *)data; 648 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 649 offlined = nr_pages; 650 if (!ret) 651 *(long *)data += offlined; 652 return ret; 653} 654 655static long 656check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 657{ 658 long offlined = 0; 659 int ret; 660 661 ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined, 662 check_pages_isolated_cb); 663 if (ret < 0) 664 offlined = (long)ret; 665 return offlined; 666} 667 668int offline_pages(unsigned long start_pfn, 669 unsigned long end_pfn, unsigned long timeout) 670{ 671 unsigned long pfn, nr_pages, expire; 672 long offlined_pages; 673 int ret, drain, retry_max, node; 674 struct zone *zone; 675 struct memory_notify arg; 676 677 BUG_ON(start_pfn >= end_pfn); 678 /* at least, alignment against pageblock is necessary */ 679 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 680 return -EINVAL; 681 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 682 return -EINVAL; 683 /* This makes hotplug much easier...and readable. 684 we assume this for now. .*/ 685 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 686 return -EINVAL; 687 688 zone = page_zone(pfn_to_page(start_pfn)); 689 node = zone_to_nid(zone); 690 nr_pages = end_pfn - start_pfn; 691 692 /* set above range as isolated */ 693 ret = start_isolate_page_range(start_pfn, end_pfn); 694 if (ret) 695 return ret; 696 697 arg.start_pfn = start_pfn; 698 arg.nr_pages = nr_pages; 699 arg.status_change_nid = -1; 700 if (nr_pages >= node_present_pages(node)) 701 arg.status_change_nid = node; 702 703 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 704 ret = notifier_to_errno(ret); 705 if (ret) 706 goto failed_removal; 707 708 pfn = start_pfn; 709 expire = jiffies + timeout; 710 drain = 0; 711 retry_max = 5; 712repeat: 713 /* start memory hot removal */ 714 ret = -EAGAIN; 715 if (time_after(jiffies, expire)) 716 goto failed_removal; 717 ret = -EINTR; 718 if (signal_pending(current)) 719 goto failed_removal; 720 ret = 0; 721 if (drain) { 722 lru_add_drain_all(); 723 flush_scheduled_work(); 724 cond_resched(); 725 drain_all_pages(); 726 } 727 728 pfn = scan_lru_pages(start_pfn, end_pfn); 729 if (pfn) { /* We have page on LRU */ 730 ret = do_migrate_range(pfn, end_pfn); 731 if (!ret) { 732 drain = 1; 733 goto repeat; 734 } else { 735 if (ret < 0) 736 if (--retry_max == 0) 737 goto failed_removal; 738 yield(); 739 drain = 1; 740 goto repeat; 741 } 742 } 743 /* drain all zone's lru pagevec, this is asyncronous... */ 744 lru_add_drain_all(); 745 flush_scheduled_work(); 746 yield(); 747 /* drain pcp pages , this is synchrouns. */ 748 drain_all_pages(); 749 /* check again */ 750 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 751 if (offlined_pages < 0) { 752 ret = -EBUSY; 753 goto failed_removal; 754 } 755 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 756 /* Ok, all of our target is islaoted. 757 We cannot do rollback at this point. */ 758 offline_isolated_pages(start_pfn, end_pfn); 759 /* reset pagetype flags and makes migrate type to be MOVABLE */ 760 undo_isolate_page_range(start_pfn, end_pfn); 761 /* removal success */ 762 zone->present_pages -= offlined_pages; 763 zone->zone_pgdat->node_present_pages -= offlined_pages; 764 totalram_pages -= offlined_pages; 765 num_physpages -= offlined_pages; 766 767 vm_total_pages = nr_free_pagecache_pages(); 768 writeback_set_ratelimit(); 769 770 memory_notify(MEM_OFFLINE, &arg); 771 return 0; 772 773failed_removal: 774 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 775 start_pfn, end_pfn); 776 memory_notify(MEM_CANCEL_OFFLINE, &arg); 777 /* pushback to free area */ 778 undo_isolate_page_range(start_pfn, end_pfn); 779 780 return ret; 781} 782#else 783int remove_memory(u64 start, u64 size) 784{ 785 return -EINVAL; 786} 787EXPORT_SYMBOL_GPL(remove_memory); 788#endif /* CONFIG_MEMORY_HOTREMOVE */ 789