memory_hotplug.c revision 0c0a4a517a31e05efb38304668198a873bfec6ca
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/* add this memory to iomem resource */ 33static struct resource *register_memory_resource(u64 start, u64 size) 34{ 35 struct resource *res; 36 res = kzalloc(sizeof(struct resource), GFP_KERNEL); 37 BUG_ON(!res); 38 39 res->name = "System RAM"; 40 res->start = start; 41 res->end = start + size - 1; 42 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; 43 if (request_resource(&iomem_resource, res) < 0) { 44 printk("System RAM resource %llx - %llx cannot be added\n", 45 (unsigned long long)res->start, (unsigned long long)res->end); 46 kfree(res); 47 res = NULL; 48 } 49 return res; 50} 51 52static void release_memory_resource(struct resource *res) 53{ 54 if (!res) 55 return; 56 release_resource(res); 57 kfree(res); 58 return; 59} 60 61#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 62#ifndef CONFIG_SPARSEMEM_VMEMMAP 63static void get_page_bootmem(unsigned long info, struct page *page, int magic) 64{ 65 atomic_set(&page->_mapcount, magic); 66 SetPagePrivate(page); 67 set_page_private(page, info); 68 atomic_inc(&page->_count); 69} 70 71void put_page_bootmem(struct page *page) 72{ 73 int magic; 74 75 magic = atomic_read(&page->_mapcount); 76 BUG_ON(magic >= -1); 77 78 if (atomic_dec_return(&page->_count) == 1) { 79 ClearPagePrivate(page); 80 set_page_private(page, 0); 81 reset_page_mapcount(page); 82 __free_pages_bootmem(page, 0); 83 } 84 85} 86 87void register_page_bootmem_info_section(unsigned long start_pfn) 88{ 89 unsigned long *usemap, mapsize, section_nr, i; 90 struct mem_section *ms; 91 struct page *page, *memmap; 92 93 if (!pfn_valid(start_pfn)) 94 return; 95 96 section_nr = pfn_to_section_nr(start_pfn); 97 ms = __nr_to_section(section_nr); 98 99 /* Get section's memmap address */ 100 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); 101 102 /* 103 * Get page for the memmap's phys address 104 * XXX: need more consideration for sparse_vmemmap... 105 */ 106 page = virt_to_page(memmap); 107 mapsize = sizeof(struct page) * PAGES_PER_SECTION; 108 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT; 109 110 /* remember memmap's page */ 111 for (i = 0; i < mapsize; i++, page++) 112 get_page_bootmem(section_nr, page, SECTION_INFO); 113 114 usemap = __nr_to_section(section_nr)->pageblock_flags; 115 page = virt_to_page(usemap); 116 117 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; 118 119 for (i = 0; i < mapsize; i++, page++) 120 get_page_bootmem(section_nr, page, MIX_INFO); 121 122} 123 124void register_page_bootmem_info_node(struct pglist_data *pgdat) 125{ 126 unsigned long i, pfn, end_pfn, nr_pages; 127 int node = pgdat->node_id; 128 struct page *page; 129 struct zone *zone; 130 131 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT; 132 page = virt_to_page(pgdat); 133 134 for (i = 0; i < nr_pages; i++, page++) 135 get_page_bootmem(node, page, NODE_INFO); 136 137 zone = &pgdat->node_zones[0]; 138 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) { 139 if (zone->wait_table) { 140 nr_pages = zone->wait_table_hash_nr_entries 141 * sizeof(wait_queue_head_t); 142 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT; 143 page = virt_to_page(zone->wait_table); 144 145 for (i = 0; i < nr_pages; i++, page++) 146 get_page_bootmem(node, page, NODE_INFO); 147 } 148 } 149 150 pfn = pgdat->node_start_pfn; 151 end_pfn = pfn + pgdat->node_spanned_pages; 152 153 /* register_section info */ 154 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) 155 register_page_bootmem_info_section(pfn); 156 157} 158#endif /* !CONFIG_SPARSEMEM_VMEMMAP */ 159 160static int __add_zone(struct zone *zone, unsigned long phys_start_pfn) 161{ 162 struct pglist_data *pgdat = zone->zone_pgdat; 163 int nr_pages = PAGES_PER_SECTION; 164 int nid = pgdat->node_id; 165 int zone_type; 166 167 zone_type = zone - pgdat->node_zones; 168 if (!zone->wait_table) { 169 int ret = 0; 170 ret = init_currently_empty_zone(zone, phys_start_pfn, 171 nr_pages, MEMMAP_HOTPLUG); 172 if (ret < 0) 173 return ret; 174 } 175 memmap_init_zone(nr_pages, nid, zone_type, 176 phys_start_pfn, MEMMAP_HOTPLUG); 177 return 0; 178} 179 180static int __add_section(struct zone *zone, unsigned long phys_start_pfn) 181{ 182 int nr_pages = PAGES_PER_SECTION; 183 int ret; 184 185 if (pfn_valid(phys_start_pfn)) 186 return -EEXIST; 187 188 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); 189 190 if (ret < 0) 191 return ret; 192 193 ret = __add_zone(zone, phys_start_pfn); 194 195 if (ret < 0) 196 return ret; 197 198 return register_new_memory(__pfn_to_section(phys_start_pfn)); 199} 200 201#ifdef CONFIG_SPARSEMEM_VMEMMAP 202static int __remove_section(struct zone *zone, struct mem_section *ms) 203{ 204 /* 205 * XXX: Freeing memmap with vmemmap is not implement yet. 206 * This should be removed later. 207 */ 208 return -EBUSY; 209} 210#else 211static int __remove_section(struct zone *zone, struct mem_section *ms) 212{ 213 unsigned long flags; 214 struct pglist_data *pgdat = zone->zone_pgdat; 215 int ret = -EINVAL; 216 217 if (!valid_section(ms)) 218 return ret; 219 220 ret = unregister_memory_section(ms); 221 if (ret) 222 return ret; 223 224 pgdat_resize_lock(pgdat, &flags); 225 sparse_remove_one_section(zone, ms); 226 pgdat_resize_unlock(pgdat, &flags); 227 return 0; 228} 229#endif 230 231/* 232 * Reasonably generic function for adding memory. It is 233 * expected that archs that support memory hotplug will 234 * call this function after deciding the zone to which to 235 * add the new pages. 236 */ 237int __add_pages(struct zone *zone, unsigned long phys_start_pfn, 238 unsigned long nr_pages) 239{ 240 unsigned long i; 241 int err = 0; 242 int start_sec, end_sec; 243 /* during initialize mem_map, align hot-added range to section */ 244 start_sec = pfn_to_section_nr(phys_start_pfn); 245 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); 246 247 for (i = start_sec; i <= end_sec; i++) { 248 err = __add_section(zone, i << PFN_SECTION_SHIFT); 249 250 /* 251 * EEXIST is finally dealt with by ioresource collision 252 * check. see add_memory() => register_memory_resource() 253 * Warning will be printed if there is collision. 254 */ 255 if (err && (err != -EEXIST)) 256 break; 257 err = 0; 258 } 259 260 return err; 261} 262EXPORT_SYMBOL_GPL(__add_pages); 263 264/** 265 * __remove_pages() - remove sections of pages from a zone 266 * @zone: zone from which pages need to be removed 267 * @phys_start_pfn: starting pageframe (must be aligned to start of a section) 268 * @nr_pages: number of pages to remove (must be multiple of section size) 269 * 270 * Generic helper function to remove section mappings and sysfs entries 271 * for the section of the memory we are removing. Caller needs to make 272 * sure that pages are marked reserved and zones are adjust properly by 273 * calling offline_pages(). 274 */ 275int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, 276 unsigned long nr_pages) 277{ 278 unsigned long i, ret = 0; 279 int sections_to_remove; 280 281 /* 282 * We can only remove entire sections 283 */ 284 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); 285 BUG_ON(nr_pages % PAGES_PER_SECTION); 286 287 release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE); 288 289 sections_to_remove = nr_pages / PAGES_PER_SECTION; 290 for (i = 0; i < sections_to_remove; i++) { 291 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; 292 ret = __remove_section(zone, __pfn_to_section(pfn)); 293 if (ret) 294 break; 295 } 296 return ret; 297} 298EXPORT_SYMBOL_GPL(__remove_pages); 299 300static void grow_zone_span(struct zone *zone, 301 unsigned long start_pfn, unsigned long end_pfn) 302{ 303 unsigned long old_zone_end_pfn; 304 305 zone_span_writelock(zone); 306 307 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; 308 if (start_pfn < zone->zone_start_pfn) 309 zone->zone_start_pfn = start_pfn; 310 311 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - 312 zone->zone_start_pfn; 313 314 zone_span_writeunlock(zone); 315} 316 317static void grow_pgdat_span(struct pglist_data *pgdat, 318 unsigned long start_pfn, unsigned long end_pfn) 319{ 320 unsigned long old_pgdat_end_pfn = 321 pgdat->node_start_pfn + pgdat->node_spanned_pages; 322 323 if (start_pfn < pgdat->node_start_pfn) 324 pgdat->node_start_pfn = start_pfn; 325 326 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - 327 pgdat->node_start_pfn; 328} 329 330void online_page(struct page *page) 331{ 332 totalram_pages++; 333 num_physpages++; 334 335#ifdef CONFIG_HIGHMEM 336 if (PageHighMem(page)) 337 totalhigh_pages++; 338#endif 339 340#ifdef CONFIG_FLATMEM 341 max_mapnr = max(page_to_pfn(page), max_mapnr); 342#endif 343 344 ClearPageReserved(page); 345 init_page_count(page); 346 __free_page(page); 347} 348 349static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, 350 void *arg) 351{ 352 unsigned long i; 353 unsigned long onlined_pages = *(unsigned long *)arg; 354 struct page *page; 355 if (PageReserved(pfn_to_page(start_pfn))) 356 for (i = 0; i < nr_pages; i++) { 357 page = pfn_to_page(start_pfn + i); 358 online_page(page); 359 onlined_pages++; 360 } 361 *(unsigned long *)arg = onlined_pages; 362 return 0; 363} 364 365 366int online_pages(unsigned long pfn, unsigned long nr_pages) 367{ 368 unsigned long flags; 369 unsigned long onlined_pages = 0; 370 struct zone *zone; 371 int need_zonelists_rebuild = 0; 372 int nid; 373 int ret; 374 struct memory_notify arg; 375 376 arg.start_pfn = pfn; 377 arg.nr_pages = nr_pages; 378 arg.status_change_nid = -1; 379 380 nid = page_to_nid(pfn_to_page(pfn)); 381 if (node_present_pages(nid) == 0) 382 arg.status_change_nid = nid; 383 384 ret = memory_notify(MEM_GOING_ONLINE, &arg); 385 ret = notifier_to_errno(ret); 386 if (ret) { 387 memory_notify(MEM_CANCEL_ONLINE, &arg); 388 return ret; 389 } 390 /* 391 * This doesn't need a lock to do pfn_to_page(). 392 * The section can't be removed here because of the 393 * memory_block->state_mutex. 394 */ 395 zone = page_zone(pfn_to_page(pfn)); 396 pgdat_resize_lock(zone->zone_pgdat, &flags); 397 grow_zone_span(zone, pfn, pfn + nr_pages); 398 grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages); 399 pgdat_resize_unlock(zone->zone_pgdat, &flags); 400 401 /* 402 * If this zone is not populated, then it is not in zonelist. 403 * This means the page allocator ignores this zone. 404 * So, zonelist must be updated after online. 405 */ 406 if (!populated_zone(zone)) 407 need_zonelists_rebuild = 1; 408 409 walk_memory_resource(pfn, nr_pages, &onlined_pages, 410 online_pages_range); 411 zone->present_pages += onlined_pages; 412 zone->zone_pgdat->node_present_pages += onlined_pages; 413 414 setup_per_zone_pages_min(); 415 if (onlined_pages) { 416 kswapd_run(zone_to_nid(zone)); 417 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); 418 } 419 420 if (need_zonelists_rebuild) 421 build_all_zonelists(); 422 vm_total_pages = nr_free_pagecache_pages(); 423 writeback_set_ratelimit(); 424 425 if (onlined_pages) 426 memory_notify(MEM_ONLINE, &arg); 427 428 return 0; 429} 430#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 431 432static pg_data_t *hotadd_new_pgdat(int nid, u64 start) 433{ 434 struct pglist_data *pgdat; 435 unsigned long zones_size[MAX_NR_ZONES] = {0}; 436 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 437 unsigned long start_pfn = start >> PAGE_SHIFT; 438 439 pgdat = arch_alloc_nodedata(nid); 440 if (!pgdat) 441 return NULL; 442 443 arch_refresh_nodedata(nid, pgdat); 444 445 /* we can use NODE_DATA(nid) from here */ 446 447 /* init node's zones as empty zones, we don't have any present pages.*/ 448 free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size); 449 450 return pgdat; 451} 452 453static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 454{ 455 arch_refresh_nodedata(nid, NULL); 456 arch_free_nodedata(pgdat); 457 return; 458} 459 460 461int add_memory(int nid, u64 start, u64 size) 462{ 463 pg_data_t *pgdat = NULL; 464 int new_pgdat = 0; 465 struct resource *res; 466 int ret; 467 468 res = register_memory_resource(start, size); 469 if (!res) 470 return -EEXIST; 471 472 if (!node_online(nid)) { 473 pgdat = hotadd_new_pgdat(nid, start); 474 if (!pgdat) 475 return -ENOMEM; 476 new_pgdat = 1; 477 } 478 479 /* call arch's memory hotadd */ 480 ret = arch_add_memory(nid, start, size); 481 482 if (ret < 0) 483 goto error; 484 485 /* we online node here. we can't roll back from here. */ 486 node_set_online(nid); 487 488 cpuset_track_online_nodes(); 489 490 if (new_pgdat) { 491 ret = register_one_node(nid); 492 /* 493 * If sysfs file of new node can't create, cpu on the node 494 * can't be hot-added. There is no rollback way now. 495 * So, check by BUG_ON() to catch it reluctantly.. 496 */ 497 BUG_ON(ret); 498 } 499 500 return ret; 501error: 502 /* rollback pgdat allocation and others */ 503 if (new_pgdat) 504 rollback_node_hotadd(nid, pgdat); 505 if (res) 506 release_memory_resource(res); 507 508 return ret; 509} 510EXPORT_SYMBOL_GPL(add_memory); 511 512#ifdef CONFIG_MEMORY_HOTREMOVE 513/* 514 * Confirm all pages in a range [start, end) is belongs to the same zone. 515 */ 516static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 517{ 518 unsigned long pfn; 519 struct zone *zone = NULL; 520 struct page *page; 521 int i; 522 for (pfn = start_pfn; 523 pfn < end_pfn; 524 pfn += MAX_ORDER_NR_PAGES) { 525 i = 0; 526 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 527 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 528 i++; 529 if (i == MAX_ORDER_NR_PAGES) 530 continue; 531 page = pfn_to_page(pfn + i); 532 if (zone && page_zone(page) != zone) 533 return 0; 534 zone = page_zone(page); 535 } 536 return 1; 537} 538 539/* 540 * Scanning pfn is much easier than scanning lru list. 541 * Scan pfn from start to end and Find LRU page. 542 */ 543int scan_lru_pages(unsigned long start, unsigned long end) 544{ 545 unsigned long pfn; 546 struct page *page; 547 for (pfn = start; pfn < end; pfn++) { 548 if (pfn_valid(pfn)) { 549 page = pfn_to_page(pfn); 550 if (PageLRU(page)) 551 return pfn; 552 } 553 } 554 return 0; 555} 556 557static struct page * 558hotremove_migrate_alloc(struct page *page, 559 unsigned long private, 560 int **x) 561{ 562 /* This should be improoooooved!! */ 563 return alloc_page(GFP_HIGHUSER_PAGECACHE); 564} 565 566 567#define NR_OFFLINE_AT_ONCE_PAGES (256) 568static int 569do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 570{ 571 unsigned long pfn; 572 struct page *page; 573 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 574 int not_managed = 0; 575 int ret = 0; 576 LIST_HEAD(source); 577 578 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 579 if (!pfn_valid(pfn)) 580 continue; 581 page = pfn_to_page(pfn); 582 if (!page_count(page)) 583 continue; 584 /* 585 * We can skip free pages. And we can only deal with pages on 586 * LRU. 587 */ 588 ret = isolate_lru_page(page, &source); 589 if (!ret) { /* Success */ 590 move_pages--; 591 } else { 592 /* Becasue we don't have big zone->lock. we should 593 check this again here. */ 594 if (page_count(page)) 595 not_managed++; 596#ifdef CONFIG_DEBUG_VM 597 printk(KERN_INFO "removing from LRU failed" 598 " %lx/%d/%lx\n", 599 pfn, page_count(page), page->flags); 600#endif 601 } 602 } 603 ret = -EBUSY; 604 if (not_managed) { 605 if (!list_empty(&source)) 606 putback_lru_pages(&source); 607 goto out; 608 } 609 ret = 0; 610 if (list_empty(&source)) 611 goto out; 612 /* this function returns # of failed pages */ 613 ret = migrate_pages(&source, hotremove_migrate_alloc, 0); 614 615out: 616 return ret; 617} 618 619/* 620 * remove from free_area[] and mark all as Reserved. 621 */ 622static int 623offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 624 void *data) 625{ 626 __offline_isolated_pages(start, start + nr_pages); 627 return 0; 628} 629 630static void 631offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 632{ 633 walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL, 634 offline_isolated_pages_cb); 635} 636 637/* 638 * Check all pages in range, recoreded as memory resource, are isolated. 639 */ 640static int 641check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 642 void *data) 643{ 644 int ret; 645 long offlined = *(long *)data; 646 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 647 offlined = nr_pages; 648 if (!ret) 649 *(long *)data += offlined; 650 return ret; 651} 652 653static long 654check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 655{ 656 long offlined = 0; 657 int ret; 658 659 ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined, 660 check_pages_isolated_cb); 661 if (ret < 0) 662 offlined = (long)ret; 663 return offlined; 664} 665 666int offline_pages(unsigned long start_pfn, 667 unsigned long end_pfn, unsigned long timeout) 668{ 669 unsigned long pfn, nr_pages, expire; 670 long offlined_pages; 671 int ret, drain, retry_max, node; 672 struct zone *zone; 673 struct memory_notify arg; 674 675 BUG_ON(start_pfn >= end_pfn); 676 /* at least, alignment against pageblock is necessary */ 677 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 678 return -EINVAL; 679 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 680 return -EINVAL; 681 /* This makes hotplug much easier...and readable. 682 we assume this for now. .*/ 683 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 684 return -EINVAL; 685 686 zone = page_zone(pfn_to_page(start_pfn)); 687 node = zone_to_nid(zone); 688 nr_pages = end_pfn - start_pfn; 689 690 /* set above range as isolated */ 691 ret = start_isolate_page_range(start_pfn, end_pfn); 692 if (ret) 693 return ret; 694 695 arg.start_pfn = start_pfn; 696 arg.nr_pages = nr_pages; 697 arg.status_change_nid = -1; 698 if (nr_pages >= node_present_pages(node)) 699 arg.status_change_nid = node; 700 701 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 702 ret = notifier_to_errno(ret); 703 if (ret) 704 goto failed_removal; 705 706 pfn = start_pfn; 707 expire = jiffies + timeout; 708 drain = 0; 709 retry_max = 5; 710repeat: 711 /* start memory hot removal */ 712 ret = -EAGAIN; 713 if (time_after(jiffies, expire)) 714 goto failed_removal; 715 ret = -EINTR; 716 if (signal_pending(current)) 717 goto failed_removal; 718 ret = 0; 719 if (drain) { 720 lru_add_drain_all(); 721 flush_scheduled_work(); 722 cond_resched(); 723 drain_all_pages(); 724 } 725 726 pfn = scan_lru_pages(start_pfn, end_pfn); 727 if (pfn) { /* We have page on LRU */ 728 ret = do_migrate_range(pfn, end_pfn); 729 if (!ret) { 730 drain = 1; 731 goto repeat; 732 } else { 733 if (ret < 0) 734 if (--retry_max == 0) 735 goto failed_removal; 736 yield(); 737 drain = 1; 738 goto repeat; 739 } 740 } 741 /* drain all zone's lru pagevec, this is asyncronous... */ 742 lru_add_drain_all(); 743 flush_scheduled_work(); 744 yield(); 745 /* drain pcp pages , this is synchrouns. */ 746 drain_all_pages(); 747 /* check again */ 748 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 749 if (offlined_pages < 0) { 750 ret = -EBUSY; 751 goto failed_removal; 752 } 753 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 754 /* Ok, all of our target is islaoted. 755 We cannot do rollback at this point. */ 756 offline_isolated_pages(start_pfn, end_pfn); 757 /* reset pagetype flags and makes migrate type to be MOVABLE */ 758 undo_isolate_page_range(start_pfn, end_pfn); 759 /* removal success */ 760 zone->present_pages -= offlined_pages; 761 zone->zone_pgdat->node_present_pages -= offlined_pages; 762 totalram_pages -= offlined_pages; 763 num_physpages -= offlined_pages; 764 765 vm_total_pages = nr_free_pagecache_pages(); 766 writeback_set_ratelimit(); 767 768 memory_notify(MEM_OFFLINE, &arg); 769 return 0; 770 771failed_removal: 772 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 773 start_pfn, end_pfn); 774 memory_notify(MEM_CANCEL_OFFLINE, &arg); 775 /* pushback to free area */ 776 undo_isolate_page_range(start_pfn, end_pfn); 777 778 return ret; 779} 780#else 781int remove_memory(u64 start, u64 size) 782{ 783 return -EINVAL; 784} 785EXPORT_SYMBOL_GPL(remove_memory); 786#endif /* CONFIG_MEMORY_HOTREMOVE */ 787