memory_hotplug.c revision fd8a4221ad76df700ff34875c9fbc42302aa4ba3
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 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); 175 return 0; 176} 177 178static int __add_section(struct zone *zone, unsigned long phys_start_pfn) 179{ 180 int nr_pages = PAGES_PER_SECTION; 181 int ret; 182 183 if (pfn_valid(phys_start_pfn)) 184 return -EEXIST; 185 186 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); 187 188 if (ret < 0) 189 return ret; 190 191 ret = __add_zone(zone, phys_start_pfn); 192 193 if (ret < 0) 194 return ret; 195 196 return register_new_memory(__pfn_to_section(phys_start_pfn)); 197} 198 199#ifdef CONFIG_SPARSEMEM_VMEMMAP 200static int __remove_section(struct zone *zone, struct mem_section *ms) 201{ 202 /* 203 * XXX: Freeing memmap with vmemmap is not implement yet. 204 * This should be removed later. 205 */ 206 return -EBUSY; 207} 208#else 209static int __remove_section(struct zone *zone, struct mem_section *ms) 210{ 211 unsigned long flags; 212 struct pglist_data *pgdat = zone->zone_pgdat; 213 int ret = -EINVAL; 214 215 if (!valid_section(ms)) 216 return ret; 217 218 ret = unregister_memory_section(ms); 219 if (ret) 220 return ret; 221 222 pgdat_resize_lock(pgdat, &flags); 223 sparse_remove_one_section(zone, ms); 224 pgdat_resize_unlock(pgdat, &flags); 225 return 0; 226} 227#endif 228 229/* 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 233 * add the new pages. 234 */ 235int __add_pages(struct zone *zone, unsigned long phys_start_pfn, 236 unsigned long nr_pages) 237{ 238 unsigned long i; 239 int err = 0; 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); 244 245 for (i = start_sec; i <= end_sec; i++) { 246 err = __add_section(zone, i << PFN_SECTION_SHIFT); 247 248 /* 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. 252 */ 253 if (err && (err != -EEXIST)) 254 break; 255 err = 0; 256 } 257 258 return err; 259} 260EXPORT_SYMBOL_GPL(__add_pages); 261 262/** 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) 267 * 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(). 272 */ 273int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, 274 unsigned long nr_pages) 275{ 276 unsigned long i, ret = 0; 277 int sections_to_remove; 278 279 /* 280 * We can only remove entire sections 281 */ 282 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); 283 BUG_ON(nr_pages % PAGES_PER_SECTION); 284 285 release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE); 286 287 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)); 291 if (ret) 292 break; 293 } 294 return ret; 295} 296EXPORT_SYMBOL_GPL(__remove_pages); 297 298static void grow_zone_span(struct zone *zone, 299 unsigned long start_pfn, unsigned long end_pfn) 300{ 301 unsigned long old_zone_end_pfn; 302 303 zone_span_writelock(zone); 304 305 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; 308 309 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - 310 zone->zone_start_pfn; 311 312 zone_span_writeunlock(zone); 313} 314 315static void grow_pgdat_span(struct pglist_data *pgdat, 316 unsigned long start_pfn, unsigned long end_pfn) 317{ 318 unsigned long old_pgdat_end_pfn = 319 pgdat->node_start_pfn + pgdat->node_spanned_pages; 320 321 if (start_pfn < pgdat->node_start_pfn) 322 pgdat->node_start_pfn = start_pfn; 323 324 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - 325 pgdat->node_start_pfn; 326} 327 328void online_page(struct page *page) 329{ 330 totalram_pages++; 331 num_physpages++; 332 333#ifdef CONFIG_HIGHMEM 334 if (PageHighMem(page)) 335 totalhigh_pages++; 336#endif 337 338#ifdef CONFIG_FLATMEM 339 max_mapnr = max(page_to_pfn(page), max_mapnr); 340#endif 341 342 ClearPageReserved(page); 343 init_page_count(page); 344 __free_page(page); 345} 346 347static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, 348 void *arg) 349{ 350 unsigned long i; 351 unsigned long onlined_pages = *(unsigned long *)arg; 352 struct page *page; 353 if (PageReserved(pfn_to_page(start_pfn))) 354 for (i = 0; i < nr_pages; i++) { 355 page = pfn_to_page(start_pfn + i); 356 online_page(page); 357 onlined_pages++; 358 } 359 *(unsigned long *)arg = onlined_pages; 360 return 0; 361} 362 363 364int online_pages(unsigned long pfn, unsigned long nr_pages) 365{ 366 unsigned long flags; 367 unsigned long onlined_pages = 0; 368 struct zone *zone; 369 int need_zonelists_rebuild = 0; 370 int nid; 371 int ret; 372 struct memory_notify arg; 373 374 arg.start_pfn = pfn; 375 arg.nr_pages = nr_pages; 376 arg.status_change_nid = -1; 377 378 nid = page_to_nid(pfn_to_page(pfn)); 379 if (node_present_pages(nid) == 0) 380 arg.status_change_nid = nid; 381 382 ret = memory_notify(MEM_GOING_ONLINE, &arg); 383 ret = notifier_to_errno(ret); 384 if (ret) { 385 memory_notify(MEM_CANCEL_ONLINE, &arg); 386 return ret; 387 } 388 /* 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. 392 */ 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); 398 399 /* 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. 403 */ 404 if (!populated_zone(zone)) 405 need_zonelists_rebuild = 1; 406 407 ret = walk_memory_resource(pfn, nr_pages, &onlined_pages, 408 online_pages_range); 409 if (ret) { 410 printk(KERN_DEBUG "online_pages %lx at %lx failed\n", 411 nr_pages, pfn); 412 memory_notify(MEM_CANCEL_ONLINE, &arg); 413 return ret; 414 } 415 416 zone->present_pages += onlined_pages; 417 zone->zone_pgdat->node_present_pages += onlined_pages; 418 419 setup_per_zone_pages_min(); 420 if (onlined_pages) { 421 kswapd_run(zone_to_nid(zone)); 422 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); 423 } 424 425 if (need_zonelists_rebuild) 426 build_all_zonelists(); 427 vm_total_pages = nr_free_pagecache_pages(); 428 writeback_set_ratelimit(); 429 430 if (onlined_pages) 431 memory_notify(MEM_ONLINE, &arg); 432 433 return 0; 434} 435#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 436 437static pg_data_t *hotadd_new_pgdat(int nid, u64 start) 438{ 439 struct pglist_data *pgdat; 440 unsigned long zones_size[MAX_NR_ZONES] = {0}; 441 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 442 unsigned long start_pfn = start >> PAGE_SHIFT; 443 444 pgdat = arch_alloc_nodedata(nid); 445 if (!pgdat) 446 return NULL; 447 448 arch_refresh_nodedata(nid, pgdat); 449 450 /* we can use NODE_DATA(nid) from here */ 451 452 /* init node's zones as empty zones, we don't have any present pages.*/ 453 free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size); 454 455 return pgdat; 456} 457 458static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 459{ 460 arch_refresh_nodedata(nid, NULL); 461 arch_free_nodedata(pgdat); 462 return; 463} 464 465 466int add_memory(int nid, u64 start, u64 size) 467{ 468 pg_data_t *pgdat = NULL; 469 int new_pgdat = 0; 470 struct resource *res; 471 int ret; 472 473 res = register_memory_resource(start, size); 474 if (!res) 475 return -EEXIST; 476 477 if (!node_online(nid)) { 478 pgdat = hotadd_new_pgdat(nid, start); 479 if (!pgdat) 480 return -ENOMEM; 481 new_pgdat = 1; 482 } 483 484 /* call arch's memory hotadd */ 485 ret = arch_add_memory(nid, start, size); 486 487 if (ret < 0) 488 goto error; 489 490 /* we online node here. we can't roll back from here. */ 491 node_set_online(nid); 492 493 cpuset_track_online_nodes(); 494 495 if (new_pgdat) { 496 ret = register_one_node(nid); 497 /* 498 * If sysfs file of new node can't create, cpu on the node 499 * can't be hot-added. There is no rollback way now. 500 * So, check by BUG_ON() to catch it reluctantly.. 501 */ 502 BUG_ON(ret); 503 } 504 505 return ret; 506error: 507 /* rollback pgdat allocation and others */ 508 if (new_pgdat) 509 rollback_node_hotadd(nid, pgdat); 510 if (res) 511 release_memory_resource(res); 512 513 return ret; 514} 515EXPORT_SYMBOL_GPL(add_memory); 516 517#ifdef CONFIG_MEMORY_HOTREMOVE 518/* 519 * Confirm all pages in a range [start, end) is belongs to the same zone. 520 */ 521static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 522{ 523 unsigned long pfn; 524 struct zone *zone = NULL; 525 struct page *page; 526 int i; 527 for (pfn = start_pfn; 528 pfn < end_pfn; 529 pfn += MAX_ORDER_NR_PAGES) { 530 i = 0; 531 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 532 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 533 i++; 534 if (i == MAX_ORDER_NR_PAGES) 535 continue; 536 page = pfn_to_page(pfn + i); 537 if (zone && page_zone(page) != zone) 538 return 0; 539 zone = page_zone(page); 540 } 541 return 1; 542} 543 544/* 545 * Scanning pfn is much easier than scanning lru list. 546 * Scan pfn from start to end and Find LRU page. 547 */ 548int scan_lru_pages(unsigned long start, unsigned long end) 549{ 550 unsigned long pfn; 551 struct page *page; 552 for (pfn = start; pfn < end; pfn++) { 553 if (pfn_valid(pfn)) { 554 page = pfn_to_page(pfn); 555 if (PageLRU(page)) 556 return pfn; 557 } 558 } 559 return 0; 560} 561 562static struct page * 563hotremove_migrate_alloc(struct page *page, 564 unsigned long private, 565 int **x) 566{ 567 /* This should be improoooooved!! */ 568 return alloc_page(GFP_HIGHUSER_PAGECACHE); 569} 570 571 572#define NR_OFFLINE_AT_ONCE_PAGES (256) 573static int 574do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 575{ 576 unsigned long pfn; 577 struct page *page; 578 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 579 int not_managed = 0; 580 int ret = 0; 581 LIST_HEAD(source); 582 583 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 584 if (!pfn_valid(pfn)) 585 continue; 586 page = pfn_to_page(pfn); 587 if (!page_count(page)) 588 continue; 589 /* 590 * We can skip free pages. And we can only deal with pages on 591 * LRU. 592 */ 593 ret = isolate_lru_page(page, &source); 594 if (!ret) { /* Success */ 595 move_pages--; 596 } else { 597 /* Becasue we don't have big zone->lock. we should 598 check this again here. */ 599 if (page_count(page)) 600 not_managed++; 601#ifdef CONFIG_DEBUG_VM 602 printk(KERN_INFO "removing from LRU failed" 603 " %lx/%d/%lx\n", 604 pfn, page_count(page), page->flags); 605#endif 606 } 607 } 608 ret = -EBUSY; 609 if (not_managed) { 610 if (!list_empty(&source)) 611 putback_lru_pages(&source); 612 goto out; 613 } 614 ret = 0; 615 if (list_empty(&source)) 616 goto out; 617 /* this function returns # of failed pages */ 618 ret = migrate_pages(&source, hotremove_migrate_alloc, 0); 619 620out: 621 return ret; 622} 623 624/* 625 * remove from free_area[] and mark all as Reserved. 626 */ 627static int 628offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 629 void *data) 630{ 631 __offline_isolated_pages(start, start + nr_pages); 632 return 0; 633} 634 635static void 636offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 637{ 638 walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL, 639 offline_isolated_pages_cb); 640} 641 642/* 643 * Check all pages in range, recoreded as memory resource, are isolated. 644 */ 645static int 646check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 647 void *data) 648{ 649 int ret; 650 long offlined = *(long *)data; 651 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 652 offlined = nr_pages; 653 if (!ret) 654 *(long *)data += offlined; 655 return ret; 656} 657 658static long 659check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 660{ 661 long offlined = 0; 662 int ret; 663 664 ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined, 665 check_pages_isolated_cb); 666 if (ret < 0) 667 offlined = (long)ret; 668 return offlined; 669} 670 671int offline_pages(unsigned long start_pfn, 672 unsigned long end_pfn, unsigned long timeout) 673{ 674 unsigned long pfn, nr_pages, expire; 675 long offlined_pages; 676 int ret, drain, retry_max, node; 677 struct zone *zone; 678 struct memory_notify arg; 679 680 BUG_ON(start_pfn >= end_pfn); 681 /* at least, alignment against pageblock is necessary */ 682 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 683 return -EINVAL; 684 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 685 return -EINVAL; 686 /* This makes hotplug much easier...and readable. 687 we assume this for now. .*/ 688 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 689 return -EINVAL; 690 691 zone = page_zone(pfn_to_page(start_pfn)); 692 node = zone_to_nid(zone); 693 nr_pages = end_pfn - start_pfn; 694 695 /* set above range as isolated */ 696 ret = start_isolate_page_range(start_pfn, end_pfn); 697 if (ret) 698 return ret; 699 700 arg.start_pfn = start_pfn; 701 arg.nr_pages = nr_pages; 702 arg.status_change_nid = -1; 703 if (nr_pages >= node_present_pages(node)) 704 arg.status_change_nid = node; 705 706 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 707 ret = notifier_to_errno(ret); 708 if (ret) 709 goto failed_removal; 710 711 pfn = start_pfn; 712 expire = jiffies + timeout; 713 drain = 0; 714 retry_max = 5; 715repeat: 716 /* start memory hot removal */ 717 ret = -EAGAIN; 718 if (time_after(jiffies, expire)) 719 goto failed_removal; 720 ret = -EINTR; 721 if (signal_pending(current)) 722 goto failed_removal; 723 ret = 0; 724 if (drain) { 725 lru_add_drain_all(); 726 flush_scheduled_work(); 727 cond_resched(); 728 drain_all_pages(); 729 } 730 731 pfn = scan_lru_pages(start_pfn, end_pfn); 732 if (pfn) { /* We have page on LRU */ 733 ret = do_migrate_range(pfn, end_pfn); 734 if (!ret) { 735 drain = 1; 736 goto repeat; 737 } else { 738 if (ret < 0) 739 if (--retry_max == 0) 740 goto failed_removal; 741 yield(); 742 drain = 1; 743 goto repeat; 744 } 745 } 746 /* drain all zone's lru pagevec, this is asyncronous... */ 747 lru_add_drain_all(); 748 flush_scheduled_work(); 749 yield(); 750 /* drain pcp pages , this is synchrouns. */ 751 drain_all_pages(); 752 /* check again */ 753 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 754 if (offlined_pages < 0) { 755 ret = -EBUSY; 756 goto failed_removal; 757 } 758 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 759 /* Ok, all of our target is islaoted. 760 We cannot do rollback at this point. */ 761 offline_isolated_pages(start_pfn, end_pfn); 762 /* reset pagetype flags and makes migrate type to be MOVABLE */ 763 undo_isolate_page_range(start_pfn, end_pfn); 764 /* removal success */ 765 zone->present_pages -= offlined_pages; 766 zone->zone_pgdat->node_present_pages -= offlined_pages; 767 totalram_pages -= offlined_pages; 768 num_physpages -= offlined_pages; 769 770 vm_total_pages = nr_free_pagecache_pages(); 771 writeback_set_ratelimit(); 772 773 memory_notify(MEM_OFFLINE, &arg); 774 return 0; 775 776failed_removal: 777 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 778 start_pfn, end_pfn); 779 memory_notify(MEM_CANCEL_OFFLINE, &arg); 780 /* pushback to free area */ 781 undo_isolate_page_range(start_pfn, end_pfn); 782 783 return ret; 784} 785#else 786int remove_memory(u64 start, u64 size) 787{ 788 return -EINVAL; 789} 790EXPORT_SYMBOL_GPL(remove_memory); 791#endif /* CONFIG_MEMORY_HOTREMOVE */ 792