memory_hotplug.c revision de7f0cba96786cf9ec9da4532c1b25f733da9b6f
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#include <linux/pfn.h> 30 31#include <asm/tlbflush.h> 32 33#include "internal.h" 34 35/* add this memory to iomem resource */ 36static struct resource *register_memory_resource(u64 start, u64 size) 37{ 38 struct resource *res; 39 res = kzalloc(sizeof(struct resource), GFP_KERNEL); 40 BUG_ON(!res); 41 42 res->name = "System RAM"; 43 res->start = start; 44 res->end = start + size - 1; 45 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; 46 if (request_resource(&iomem_resource, res) < 0) { 47 printk("System RAM resource %llx - %llx cannot be added\n", 48 (unsigned long long)res->start, (unsigned long long)res->end); 49 kfree(res); 50 res = NULL; 51 } 52 return res; 53} 54 55static void release_memory_resource(struct resource *res) 56{ 57 if (!res) 58 return; 59 release_resource(res); 60 kfree(res); 61 return; 62} 63 64#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 65#ifndef CONFIG_SPARSEMEM_VMEMMAP 66static void get_page_bootmem(unsigned long info, struct page *page, int type) 67{ 68 atomic_set(&page->_mapcount, type); 69 SetPagePrivate(page); 70 set_page_private(page, info); 71 atomic_inc(&page->_count); 72} 73 74void put_page_bootmem(struct page *page) 75{ 76 int type; 77 78 type = atomic_read(&page->_mapcount); 79 BUG_ON(type >= -1); 80 81 if (atomic_dec_return(&page->_count) == 1) { 82 ClearPagePrivate(page); 83 set_page_private(page, 0); 84 reset_page_mapcount(page); 85 __free_pages_bootmem(page, 0); 86 } 87 88} 89 90static void register_page_bootmem_info_section(unsigned long start_pfn) 91{ 92 unsigned long *usemap, mapsize, section_nr, i; 93 struct mem_section *ms; 94 struct page *page, *memmap; 95 96 if (!pfn_valid(start_pfn)) 97 return; 98 99 section_nr = pfn_to_section_nr(start_pfn); 100 ms = __nr_to_section(section_nr); 101 102 /* Get section's memmap address */ 103 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); 104 105 /* 106 * Get page for the memmap's phys address 107 * XXX: need more consideration for sparse_vmemmap... 108 */ 109 page = virt_to_page(memmap); 110 mapsize = sizeof(struct page) * PAGES_PER_SECTION; 111 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT; 112 113 /* remember memmap's page */ 114 for (i = 0; i < mapsize; i++, page++) 115 get_page_bootmem(section_nr, page, SECTION_INFO); 116 117 usemap = __nr_to_section(section_nr)->pageblock_flags; 118 page = virt_to_page(usemap); 119 120 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; 121 122 for (i = 0; i < mapsize; i++, page++) 123 get_page_bootmem(section_nr, page, MIX_SECTION_INFO); 124 125} 126 127void register_page_bootmem_info_node(struct pglist_data *pgdat) 128{ 129 unsigned long i, pfn, end_pfn, nr_pages; 130 int node = pgdat->node_id; 131 struct page *page; 132 struct zone *zone; 133 134 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT; 135 page = virt_to_page(pgdat); 136 137 for (i = 0; i < nr_pages; i++, page++) 138 get_page_bootmem(node, page, NODE_INFO); 139 140 zone = &pgdat->node_zones[0]; 141 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) { 142 if (zone->wait_table) { 143 nr_pages = zone->wait_table_hash_nr_entries 144 * sizeof(wait_queue_head_t); 145 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT; 146 page = virt_to_page(zone->wait_table); 147 148 for (i = 0; i < nr_pages; i++, page++) 149 get_page_bootmem(node, page, NODE_INFO); 150 } 151 } 152 153 pfn = pgdat->node_start_pfn; 154 end_pfn = pfn + pgdat->node_spanned_pages; 155 156 /* register_section info */ 157 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) 158 register_page_bootmem_info_section(pfn); 159 160} 161#endif /* !CONFIG_SPARSEMEM_VMEMMAP */ 162 163static void grow_zone_span(struct zone *zone, unsigned long start_pfn, 164 unsigned long end_pfn) 165{ 166 unsigned long old_zone_end_pfn; 167 168 zone_span_writelock(zone); 169 170 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; 171 if (start_pfn < zone->zone_start_pfn) 172 zone->zone_start_pfn = start_pfn; 173 174 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - 175 zone->zone_start_pfn; 176 177 zone_span_writeunlock(zone); 178} 179 180static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn, 181 unsigned long end_pfn) 182{ 183 unsigned long old_pgdat_end_pfn = 184 pgdat->node_start_pfn + pgdat->node_spanned_pages; 185 186 if (start_pfn < pgdat->node_start_pfn) 187 pgdat->node_start_pfn = start_pfn; 188 189 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - 190 pgdat->node_start_pfn; 191} 192 193static int __add_zone(struct zone *zone, unsigned long phys_start_pfn) 194{ 195 struct pglist_data *pgdat = zone->zone_pgdat; 196 int nr_pages = PAGES_PER_SECTION; 197 int nid = pgdat->node_id; 198 int zone_type; 199 unsigned long flags; 200 201 zone_type = zone - pgdat->node_zones; 202 if (!zone->wait_table) { 203 int ret; 204 205 ret = init_currently_empty_zone(zone, phys_start_pfn, 206 nr_pages, MEMMAP_HOTPLUG); 207 if (ret) 208 return ret; 209 } 210 pgdat_resize_lock(zone->zone_pgdat, &flags); 211 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages); 212 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn, 213 phys_start_pfn + nr_pages); 214 pgdat_resize_unlock(zone->zone_pgdat, &flags); 215 memmap_init_zone(nr_pages, nid, zone_type, 216 phys_start_pfn, MEMMAP_HOTPLUG); 217 return 0; 218} 219 220static int __add_section(struct zone *zone, unsigned long phys_start_pfn) 221{ 222 int nr_pages = PAGES_PER_SECTION; 223 int ret; 224 225 if (pfn_valid(phys_start_pfn)) 226 return -EEXIST; 227 228 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); 229 230 if (ret < 0) 231 return ret; 232 233 ret = __add_zone(zone, phys_start_pfn); 234 235 if (ret < 0) 236 return ret; 237 238 return register_new_memory(__pfn_to_section(phys_start_pfn)); 239} 240 241#ifdef CONFIG_SPARSEMEM_VMEMMAP 242static int __remove_section(struct zone *zone, struct mem_section *ms) 243{ 244 /* 245 * XXX: Freeing memmap with vmemmap is not implement yet. 246 * This should be removed later. 247 */ 248 return -EBUSY; 249} 250#else 251static int __remove_section(struct zone *zone, struct mem_section *ms) 252{ 253 unsigned long flags; 254 struct pglist_data *pgdat = zone->zone_pgdat; 255 int ret = -EINVAL; 256 257 if (!valid_section(ms)) 258 return ret; 259 260 ret = unregister_memory_section(ms); 261 if (ret) 262 return ret; 263 264 pgdat_resize_lock(pgdat, &flags); 265 sparse_remove_one_section(zone, ms); 266 pgdat_resize_unlock(pgdat, &flags); 267 return 0; 268} 269#endif 270 271/* 272 * Reasonably generic function for adding memory. It is 273 * expected that archs that support memory hotplug will 274 * call this function after deciding the zone to which to 275 * add the new pages. 276 */ 277int __add_pages(struct zone *zone, unsigned long phys_start_pfn, 278 unsigned long nr_pages) 279{ 280 unsigned long i; 281 int err = 0; 282 int start_sec, end_sec; 283 /* during initialize mem_map, align hot-added range to section */ 284 start_sec = pfn_to_section_nr(phys_start_pfn); 285 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); 286 287 for (i = start_sec; i <= end_sec; i++) { 288 err = __add_section(zone, i << PFN_SECTION_SHIFT); 289 290 /* 291 * EEXIST is finally dealt with by ioresource collision 292 * check. see add_memory() => register_memory_resource() 293 * Warning will be printed if there is collision. 294 */ 295 if (err && (err != -EEXIST)) 296 break; 297 err = 0; 298 } 299 300 return err; 301} 302EXPORT_SYMBOL_GPL(__add_pages); 303 304/** 305 * __remove_pages() - remove sections of pages from a zone 306 * @zone: zone from which pages need to be removed 307 * @phys_start_pfn: starting pageframe (must be aligned to start of a section) 308 * @nr_pages: number of pages to remove (must be multiple of section size) 309 * 310 * Generic helper function to remove section mappings and sysfs entries 311 * for the section of the memory we are removing. Caller needs to make 312 * sure that pages are marked reserved and zones are adjust properly by 313 * calling offline_pages(). 314 */ 315int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, 316 unsigned long nr_pages) 317{ 318 unsigned long i, ret = 0; 319 int sections_to_remove; 320 321 /* 322 * We can only remove entire sections 323 */ 324 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); 325 BUG_ON(nr_pages % PAGES_PER_SECTION); 326 327 sections_to_remove = nr_pages / PAGES_PER_SECTION; 328 for (i = 0; i < sections_to_remove; i++) { 329 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; 330 release_mem_region(pfn << PAGE_SHIFT, 331 PAGES_PER_SECTION << PAGE_SHIFT); 332 ret = __remove_section(zone, __pfn_to_section(pfn)); 333 if (ret) 334 break; 335 } 336 return ret; 337} 338EXPORT_SYMBOL_GPL(__remove_pages); 339 340void online_page(struct page *page) 341{ 342 totalram_pages++; 343 num_physpages++; 344 345#ifdef CONFIG_HIGHMEM 346 if (PageHighMem(page)) 347 totalhigh_pages++; 348#endif 349 350#ifdef CONFIG_FLATMEM 351 max_mapnr = max(page_to_pfn(page), max_mapnr); 352#endif 353 354 ClearPageReserved(page); 355 init_page_count(page); 356 __free_page(page); 357} 358 359static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, 360 void *arg) 361{ 362 unsigned long i; 363 unsigned long onlined_pages = *(unsigned long *)arg; 364 struct page *page; 365 if (PageReserved(pfn_to_page(start_pfn))) 366 for (i = 0; i < nr_pages; i++) { 367 page = pfn_to_page(start_pfn + i); 368 online_page(page); 369 onlined_pages++; 370 } 371 *(unsigned long *)arg = onlined_pages; 372 return 0; 373} 374 375 376int online_pages(unsigned long pfn, unsigned long nr_pages) 377{ 378 unsigned long onlined_pages = 0; 379 struct zone *zone; 380 int need_zonelists_rebuild = 0; 381 int nid; 382 int ret; 383 struct memory_notify arg; 384 385 arg.start_pfn = pfn; 386 arg.nr_pages = nr_pages; 387 arg.status_change_nid = -1; 388 389 nid = page_to_nid(pfn_to_page(pfn)); 390 if (node_present_pages(nid) == 0) 391 arg.status_change_nid = nid; 392 393 ret = memory_notify(MEM_GOING_ONLINE, &arg); 394 ret = notifier_to_errno(ret); 395 if (ret) { 396 memory_notify(MEM_CANCEL_ONLINE, &arg); 397 return ret; 398 } 399 /* 400 * This doesn't need a lock to do pfn_to_page(). 401 * The section can't be removed here because of the 402 * memory_block->state_mutex. 403 */ 404 zone = page_zone(pfn_to_page(pfn)); 405 /* 406 * If this zone is not populated, then it is not in zonelist. 407 * This means the page allocator ignores this zone. 408 * So, zonelist must be updated after online. 409 */ 410 if (!populated_zone(zone)) 411 need_zonelists_rebuild = 1; 412 413 ret = walk_memory_resource(pfn, nr_pages, &onlined_pages, 414 online_pages_range); 415 if (ret) { 416 printk(KERN_DEBUG "online_pages %lx at %lx failed\n", 417 nr_pages, pfn); 418 memory_notify(MEM_CANCEL_ONLINE, &arg); 419 return ret; 420 } 421 422 zone->present_pages += onlined_pages; 423 zone->zone_pgdat->node_present_pages += onlined_pages; 424 425 setup_per_zone_pages_min(); 426 if (onlined_pages) { 427 kswapd_run(zone_to_nid(zone)); 428 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); 429 } 430 431 if (need_zonelists_rebuild) 432 build_all_zonelists(); 433 else 434 vm_total_pages = nr_free_pagecache_pages(); 435 436 writeback_set_ratelimit(); 437 438 if (onlined_pages) 439 memory_notify(MEM_ONLINE, &arg); 440 441 return 0; 442} 443#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 444 445static pg_data_t *hotadd_new_pgdat(int nid, u64 start) 446{ 447 struct pglist_data *pgdat; 448 unsigned long zones_size[MAX_NR_ZONES] = {0}; 449 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 450 unsigned long start_pfn = start >> PAGE_SHIFT; 451 452 pgdat = arch_alloc_nodedata(nid); 453 if (!pgdat) 454 return NULL; 455 456 arch_refresh_nodedata(nid, pgdat); 457 458 /* we can use NODE_DATA(nid) from here */ 459 460 /* init node's zones as empty zones, we don't have any present pages.*/ 461 free_area_init_node(nid, zones_size, start_pfn, zholes_size); 462 463 return pgdat; 464} 465 466static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 467{ 468 arch_refresh_nodedata(nid, NULL); 469 arch_free_nodedata(pgdat); 470 return; 471} 472 473 474int add_memory(int nid, u64 start, u64 size) 475{ 476 pg_data_t *pgdat = NULL; 477 int new_pgdat = 0; 478 struct resource *res; 479 int ret; 480 481 res = register_memory_resource(start, size); 482 if (!res) 483 return -EEXIST; 484 485 if (!node_online(nid)) { 486 pgdat = hotadd_new_pgdat(nid, start); 487 if (!pgdat) 488 return -ENOMEM; 489 new_pgdat = 1; 490 } 491 492 /* call arch's memory hotadd */ 493 ret = arch_add_memory(nid, start, size); 494 495 if (ret < 0) 496 goto error; 497 498 /* we online node here. we can't roll back from here. */ 499 node_set_online(nid); 500 501 cpuset_track_online_nodes(); 502 503 if (new_pgdat) { 504 ret = register_one_node(nid); 505 /* 506 * If sysfs file of new node can't create, cpu on the node 507 * can't be hot-added. There is no rollback way now. 508 * So, check by BUG_ON() to catch it reluctantly.. 509 */ 510 BUG_ON(ret); 511 } 512 513 return ret; 514error: 515 /* rollback pgdat allocation and others */ 516 if (new_pgdat) 517 rollback_node_hotadd(nid, pgdat); 518 if (res) 519 release_memory_resource(res); 520 521 return ret; 522} 523EXPORT_SYMBOL_GPL(add_memory); 524 525#ifdef CONFIG_MEMORY_HOTREMOVE 526/* 527 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy 528 * set and the size of the free page is given by page_order(). Using this, 529 * the function determines if the pageblock contains only free pages. 530 * Due to buddy contraints, a free page at least the size of a pageblock will 531 * be located at the start of the pageblock 532 */ 533static inline int pageblock_free(struct page *page) 534{ 535 return PageBuddy(page) && page_order(page) >= pageblock_order; 536} 537 538/* Return the start of the next active pageblock after a given page */ 539static struct page *next_active_pageblock(struct page *page) 540{ 541 int pageblocks_stride; 542 543 /* Ensure the starting page is pageblock-aligned */ 544 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1)); 545 546 /* Move forward by at least 1 * pageblock_nr_pages */ 547 pageblocks_stride = 1; 548 549 /* If the entire pageblock is free, move to the end of free page */ 550 if (pageblock_free(page)) 551 pageblocks_stride += page_order(page) - pageblock_order; 552 553 return page + (pageblocks_stride * pageblock_nr_pages); 554} 555 556/* Checks if this range of memory is likely to be hot-removable. */ 557int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) 558{ 559 int type; 560 struct page *page = pfn_to_page(start_pfn); 561 struct page *end_page = page + nr_pages; 562 563 /* Check the starting page of each pageblock within the range */ 564 for (; page < end_page; page = next_active_pageblock(page)) { 565 type = get_pageblock_migratetype(page); 566 567 /* 568 * A pageblock containing MOVABLE or free pages is considered 569 * removable 570 */ 571 if (type != MIGRATE_MOVABLE && !pageblock_free(page)) 572 return 0; 573 574 /* 575 * A pageblock starting with a PageReserved page is not 576 * considered removable. 577 */ 578 if (PageReserved(page)) 579 return 0; 580 } 581 582 /* All pageblocks in the memory block are likely to be hot-removable */ 583 return 1; 584} 585 586/* 587 * Confirm all pages in a range [start, end) is belongs to the same zone. 588 */ 589static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 590{ 591 unsigned long pfn; 592 struct zone *zone = NULL; 593 struct page *page; 594 int i; 595 for (pfn = start_pfn; 596 pfn < end_pfn; 597 pfn += MAX_ORDER_NR_PAGES) { 598 i = 0; 599 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 600 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 601 i++; 602 if (i == MAX_ORDER_NR_PAGES) 603 continue; 604 page = pfn_to_page(pfn + i); 605 if (zone && page_zone(page) != zone) 606 return 0; 607 zone = page_zone(page); 608 } 609 return 1; 610} 611 612/* 613 * Scanning pfn is much easier than scanning lru list. 614 * Scan pfn from start to end and Find LRU page. 615 */ 616int scan_lru_pages(unsigned long start, unsigned long end) 617{ 618 unsigned long pfn; 619 struct page *page; 620 for (pfn = start; pfn < end; pfn++) { 621 if (pfn_valid(pfn)) { 622 page = pfn_to_page(pfn); 623 if (PageLRU(page)) 624 return pfn; 625 } 626 } 627 return 0; 628} 629 630static struct page * 631hotremove_migrate_alloc(struct page *page, 632 unsigned long private, 633 int **x) 634{ 635 /* This should be improoooooved!! */ 636 return alloc_page(GFP_HIGHUSER_PAGECACHE); 637} 638 639 640#define NR_OFFLINE_AT_ONCE_PAGES (256) 641static int 642do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 643{ 644 unsigned long pfn; 645 struct page *page; 646 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 647 int not_managed = 0; 648 int ret = 0; 649 LIST_HEAD(source); 650 651 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 652 if (!pfn_valid(pfn)) 653 continue; 654 page = pfn_to_page(pfn); 655 if (!page_count(page)) 656 continue; 657 /* 658 * We can skip free pages. And we can only deal with pages on 659 * LRU. 660 */ 661 ret = isolate_lru_page(page); 662 if (!ret) { /* Success */ 663 list_add_tail(&page->lru, &source); 664 move_pages--; 665 } else { 666 /* Becasue we don't have big zone->lock. we should 667 check this again here. */ 668 if (page_count(page)) 669 not_managed++; 670#ifdef CONFIG_DEBUG_VM 671 printk(KERN_INFO "removing from LRU failed" 672 " %lx/%d/%lx\n", 673 pfn, page_count(page), page->flags); 674#endif 675 } 676 } 677 ret = -EBUSY; 678 if (not_managed) { 679 if (!list_empty(&source)) 680 putback_lru_pages(&source); 681 goto out; 682 } 683 ret = 0; 684 if (list_empty(&source)) 685 goto out; 686 /* this function returns # of failed pages */ 687 ret = migrate_pages(&source, hotremove_migrate_alloc, 0); 688 689out: 690 return ret; 691} 692 693/* 694 * remove from free_area[] and mark all as Reserved. 695 */ 696static int 697offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 698 void *data) 699{ 700 __offline_isolated_pages(start, start + nr_pages); 701 return 0; 702} 703 704static void 705offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 706{ 707 walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL, 708 offline_isolated_pages_cb); 709} 710 711/* 712 * Check all pages in range, recoreded as memory resource, are isolated. 713 */ 714static int 715check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 716 void *data) 717{ 718 int ret; 719 long offlined = *(long *)data; 720 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 721 offlined = nr_pages; 722 if (!ret) 723 *(long *)data += offlined; 724 return ret; 725} 726 727static long 728check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 729{ 730 long offlined = 0; 731 int ret; 732 733 ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined, 734 check_pages_isolated_cb); 735 if (ret < 0) 736 offlined = (long)ret; 737 return offlined; 738} 739 740int offline_pages(unsigned long start_pfn, 741 unsigned long end_pfn, unsigned long timeout) 742{ 743 unsigned long pfn, nr_pages, expire; 744 long offlined_pages; 745 int ret, drain, retry_max, node; 746 struct zone *zone; 747 struct memory_notify arg; 748 749 BUG_ON(start_pfn >= end_pfn); 750 /* at least, alignment against pageblock is necessary */ 751 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 752 return -EINVAL; 753 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 754 return -EINVAL; 755 /* This makes hotplug much easier...and readable. 756 we assume this for now. .*/ 757 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 758 return -EINVAL; 759 760 zone = page_zone(pfn_to_page(start_pfn)); 761 node = zone_to_nid(zone); 762 nr_pages = end_pfn - start_pfn; 763 764 /* set above range as isolated */ 765 ret = start_isolate_page_range(start_pfn, end_pfn); 766 if (ret) 767 return ret; 768 769 arg.start_pfn = start_pfn; 770 arg.nr_pages = nr_pages; 771 arg.status_change_nid = -1; 772 if (nr_pages >= node_present_pages(node)) 773 arg.status_change_nid = node; 774 775 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 776 ret = notifier_to_errno(ret); 777 if (ret) 778 goto failed_removal; 779 780 pfn = start_pfn; 781 expire = jiffies + timeout; 782 drain = 0; 783 retry_max = 5; 784repeat: 785 /* start memory hot removal */ 786 ret = -EAGAIN; 787 if (time_after(jiffies, expire)) 788 goto failed_removal; 789 ret = -EINTR; 790 if (signal_pending(current)) 791 goto failed_removal; 792 ret = 0; 793 if (drain) { 794 lru_add_drain_all(); 795 flush_scheduled_work(); 796 cond_resched(); 797 drain_all_pages(); 798 } 799 800 pfn = scan_lru_pages(start_pfn, end_pfn); 801 if (pfn) { /* We have page on LRU */ 802 ret = do_migrate_range(pfn, end_pfn); 803 if (!ret) { 804 drain = 1; 805 goto repeat; 806 } else { 807 if (ret < 0) 808 if (--retry_max == 0) 809 goto failed_removal; 810 yield(); 811 drain = 1; 812 goto repeat; 813 } 814 } 815 /* drain all zone's lru pagevec, this is asyncronous... */ 816 lru_add_drain_all(); 817 flush_scheduled_work(); 818 yield(); 819 /* drain pcp pages , this is synchrouns. */ 820 drain_all_pages(); 821 /* check again */ 822 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 823 if (offlined_pages < 0) { 824 ret = -EBUSY; 825 goto failed_removal; 826 } 827 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 828 /* Ok, all of our target is islaoted. 829 We cannot do rollback at this point. */ 830 offline_isolated_pages(start_pfn, end_pfn); 831 /* reset pagetype flags and makes migrate type to be MOVABLE */ 832 undo_isolate_page_range(start_pfn, end_pfn); 833 /* removal success */ 834 zone->present_pages -= offlined_pages; 835 zone->zone_pgdat->node_present_pages -= offlined_pages; 836 totalram_pages -= offlined_pages; 837 num_physpages -= offlined_pages; 838 839 vm_total_pages = nr_free_pagecache_pages(); 840 writeback_set_ratelimit(); 841 842 memory_notify(MEM_OFFLINE, &arg); 843 return 0; 844 845failed_removal: 846 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 847 start_pfn, end_pfn); 848 memory_notify(MEM_CANCEL_OFFLINE, &arg); 849 /* pushback to free area */ 850 undo_isolate_page_range(start_pfn, end_pfn); 851 852 return ret; 853} 854 855int remove_memory(u64 start, u64 size) 856{ 857 unsigned long start_pfn, end_pfn; 858 859 start_pfn = PFN_DOWN(start); 860 end_pfn = start_pfn + PFN_DOWN(size); 861 return offline_pages(start_pfn, end_pfn, 120 * HZ); 862} 863#else 864int remove_memory(u64 start, u64 size) 865{ 866 return -EINVAL; 867} 868#endif /* CONFIG_MEMORY_HOTREMOVE */ 869EXPORT_SYMBOL_GPL(remove_memory); 870