memory_hotplug.c revision cf608ac19c95804dc2df43b1f4f9e068aa9034ab
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/delay.h> 26#include <linux/migrate.h> 27#include <linux/page-isolation.h> 28#include <linux/pfn.h> 29#include <linux/suspend.h> 30#include <linux/mm_inline.h> 31#include <linux/firmware-map.h> 32 33#include <asm/tlbflush.h> 34 35#include "internal.h" 36 37/* add this memory to iomem resource */ 38static struct resource *register_memory_resource(u64 start, u64 size) 39{ 40 struct resource *res; 41 res = kzalloc(sizeof(struct resource), GFP_KERNEL); 42 BUG_ON(!res); 43 44 res->name = "System RAM"; 45 res->start = start; 46 res->end = start + size - 1; 47 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; 48 if (request_resource(&iomem_resource, res) < 0) { 49 printk("System RAM resource %llx - %llx cannot be added\n", 50 (unsigned long long)res->start, (unsigned long long)res->end); 51 kfree(res); 52 res = NULL; 53 } 54 return res; 55} 56 57static void release_memory_resource(struct resource *res) 58{ 59 if (!res) 60 return; 61 release_resource(res); 62 kfree(res); 63 return; 64} 65 66#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 67#ifndef CONFIG_SPARSEMEM_VMEMMAP 68static void get_page_bootmem(unsigned long info, struct page *page, int type) 69{ 70 atomic_set(&page->_mapcount, type); 71 SetPagePrivate(page); 72 set_page_private(page, info); 73 atomic_inc(&page->_count); 74} 75 76/* reference to __meminit __free_pages_bootmem is valid 77 * so use __ref to tell modpost not to generate a warning */ 78void __ref put_page_bootmem(struct page *page) 79{ 80 int type; 81 82 type = atomic_read(&page->_mapcount); 83 BUG_ON(type >= -1); 84 85 if (atomic_dec_return(&page->_count) == 1) { 86 ClearPagePrivate(page); 87 set_page_private(page, 0); 88 reset_page_mapcount(page); 89 __free_pages_bootmem(page, 0); 90 } 91 92} 93 94static void register_page_bootmem_info_section(unsigned long start_pfn) 95{ 96 unsigned long *usemap, mapsize, section_nr, i; 97 struct mem_section *ms; 98 struct page *page, *memmap; 99 100 if (!pfn_valid(start_pfn)) 101 return; 102 103 section_nr = pfn_to_section_nr(start_pfn); 104 ms = __nr_to_section(section_nr); 105 106 /* Get section's memmap address */ 107 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); 108 109 /* 110 * Get page for the memmap's phys address 111 * XXX: need more consideration for sparse_vmemmap... 112 */ 113 page = virt_to_page(memmap); 114 mapsize = sizeof(struct page) * PAGES_PER_SECTION; 115 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT; 116 117 /* remember memmap's page */ 118 for (i = 0; i < mapsize; i++, page++) 119 get_page_bootmem(section_nr, page, SECTION_INFO); 120 121 usemap = __nr_to_section(section_nr)->pageblock_flags; 122 page = virt_to_page(usemap); 123 124 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; 125 126 for (i = 0; i < mapsize; i++, page++) 127 get_page_bootmem(section_nr, page, MIX_SECTION_INFO); 128 129} 130 131void register_page_bootmem_info_node(struct pglist_data *pgdat) 132{ 133 unsigned long i, pfn, end_pfn, nr_pages; 134 int node = pgdat->node_id; 135 struct page *page; 136 struct zone *zone; 137 138 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT; 139 page = virt_to_page(pgdat); 140 141 for (i = 0; i < nr_pages; i++, page++) 142 get_page_bootmem(node, page, NODE_INFO); 143 144 zone = &pgdat->node_zones[0]; 145 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) { 146 if (zone->wait_table) { 147 nr_pages = zone->wait_table_hash_nr_entries 148 * sizeof(wait_queue_head_t); 149 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT; 150 page = virt_to_page(zone->wait_table); 151 152 for (i = 0; i < nr_pages; i++, page++) 153 get_page_bootmem(node, page, NODE_INFO); 154 } 155 } 156 157 pfn = pgdat->node_start_pfn; 158 end_pfn = pfn + pgdat->node_spanned_pages; 159 160 /* register_section info */ 161 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) 162 register_page_bootmem_info_section(pfn); 163 164} 165#endif /* !CONFIG_SPARSEMEM_VMEMMAP */ 166 167static void grow_zone_span(struct zone *zone, unsigned long start_pfn, 168 unsigned long end_pfn) 169{ 170 unsigned long old_zone_end_pfn; 171 172 zone_span_writelock(zone); 173 174 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; 175 if (start_pfn < zone->zone_start_pfn) 176 zone->zone_start_pfn = start_pfn; 177 178 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - 179 zone->zone_start_pfn; 180 181 zone_span_writeunlock(zone); 182} 183 184static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn, 185 unsigned long end_pfn) 186{ 187 unsigned long old_pgdat_end_pfn = 188 pgdat->node_start_pfn + pgdat->node_spanned_pages; 189 190 if (start_pfn < pgdat->node_start_pfn) 191 pgdat->node_start_pfn = start_pfn; 192 193 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - 194 pgdat->node_start_pfn; 195} 196 197static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn) 198{ 199 struct pglist_data *pgdat = zone->zone_pgdat; 200 int nr_pages = PAGES_PER_SECTION; 201 int nid = pgdat->node_id; 202 int zone_type; 203 unsigned long flags; 204 205 zone_type = zone - pgdat->node_zones; 206 if (!zone->wait_table) { 207 int ret; 208 209 ret = init_currently_empty_zone(zone, phys_start_pfn, 210 nr_pages, MEMMAP_HOTPLUG); 211 if (ret) 212 return ret; 213 } 214 pgdat_resize_lock(zone->zone_pgdat, &flags); 215 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages); 216 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn, 217 phys_start_pfn + nr_pages); 218 pgdat_resize_unlock(zone->zone_pgdat, &flags); 219 memmap_init_zone(nr_pages, nid, zone_type, 220 phys_start_pfn, MEMMAP_HOTPLUG); 221 return 0; 222} 223 224static int __meminit __add_section(int nid, struct zone *zone, 225 unsigned long phys_start_pfn) 226{ 227 int nr_pages = PAGES_PER_SECTION; 228 int ret; 229 230 if (pfn_valid(phys_start_pfn)) 231 return -EEXIST; 232 233 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); 234 235 if (ret < 0) 236 return ret; 237 238 ret = __add_zone(zone, phys_start_pfn); 239 240 if (ret < 0) 241 return ret; 242 243 return register_new_memory(nid, __pfn_to_section(phys_start_pfn)); 244} 245 246#ifdef CONFIG_SPARSEMEM_VMEMMAP 247static int __remove_section(struct zone *zone, struct mem_section *ms) 248{ 249 /* 250 * XXX: Freeing memmap with vmemmap is not implement yet. 251 * This should be removed later. 252 */ 253 return -EBUSY; 254} 255#else 256static int __remove_section(struct zone *zone, struct mem_section *ms) 257{ 258 unsigned long flags; 259 struct pglist_data *pgdat = zone->zone_pgdat; 260 int ret = -EINVAL; 261 262 if (!valid_section(ms)) 263 return ret; 264 265 ret = unregister_memory_section(ms); 266 if (ret) 267 return ret; 268 269 pgdat_resize_lock(pgdat, &flags); 270 sparse_remove_one_section(zone, ms); 271 pgdat_resize_unlock(pgdat, &flags); 272 return 0; 273} 274#endif 275 276/* 277 * Reasonably generic function for adding memory. It is 278 * expected that archs that support memory hotplug will 279 * call this function after deciding the zone to which to 280 * add the new pages. 281 */ 282int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn, 283 unsigned long nr_pages) 284{ 285 unsigned long i; 286 int err = 0; 287 int start_sec, end_sec; 288 /* during initialize mem_map, align hot-added range to section */ 289 start_sec = pfn_to_section_nr(phys_start_pfn); 290 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); 291 292 for (i = start_sec; i <= end_sec; i++) { 293 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT); 294 295 /* 296 * EEXIST is finally dealt with by ioresource collision 297 * check. see add_memory() => register_memory_resource() 298 * Warning will be printed if there is collision. 299 */ 300 if (err && (err != -EEXIST)) 301 break; 302 err = 0; 303 } 304 305 return err; 306} 307EXPORT_SYMBOL_GPL(__add_pages); 308 309/** 310 * __remove_pages() - remove sections of pages from a zone 311 * @zone: zone from which pages need to be removed 312 * @phys_start_pfn: starting pageframe (must be aligned to start of a section) 313 * @nr_pages: number of pages to remove (must be multiple of section size) 314 * 315 * Generic helper function to remove section mappings and sysfs entries 316 * for the section of the memory we are removing. Caller needs to make 317 * sure that pages are marked reserved and zones are adjust properly by 318 * calling offline_pages(). 319 */ 320int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, 321 unsigned long nr_pages) 322{ 323 unsigned long i, ret = 0; 324 int sections_to_remove; 325 326 /* 327 * We can only remove entire sections 328 */ 329 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); 330 BUG_ON(nr_pages % PAGES_PER_SECTION); 331 332 sections_to_remove = nr_pages / PAGES_PER_SECTION; 333 for (i = 0; i < sections_to_remove; i++) { 334 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; 335 release_mem_region(pfn << PAGE_SHIFT, 336 PAGES_PER_SECTION << PAGE_SHIFT); 337 ret = __remove_section(zone, __pfn_to_section(pfn)); 338 if (ret) 339 break; 340 } 341 return ret; 342} 343EXPORT_SYMBOL_GPL(__remove_pages); 344 345void online_page(struct page *page) 346{ 347 unsigned long pfn = page_to_pfn(page); 348 349 totalram_pages++; 350 if (pfn >= num_physpages) 351 num_physpages = pfn + 1; 352 353#ifdef CONFIG_HIGHMEM 354 if (PageHighMem(page)) 355 totalhigh_pages++; 356#endif 357 358#ifdef CONFIG_FLATMEM 359 max_mapnr = max(page_to_pfn(page), max_mapnr); 360#endif 361 362 ClearPageReserved(page); 363 init_page_count(page); 364 __free_page(page); 365} 366 367static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, 368 void *arg) 369{ 370 unsigned long i; 371 unsigned long onlined_pages = *(unsigned long *)arg; 372 struct page *page; 373 if (PageReserved(pfn_to_page(start_pfn))) 374 for (i = 0; i < nr_pages; i++) { 375 page = pfn_to_page(start_pfn + i); 376 online_page(page); 377 onlined_pages++; 378 } 379 *(unsigned long *)arg = onlined_pages; 380 return 0; 381} 382 383 384int online_pages(unsigned long pfn, unsigned long nr_pages) 385{ 386 unsigned long onlined_pages = 0; 387 struct zone *zone; 388 int need_zonelists_rebuild = 0; 389 int nid; 390 int ret; 391 struct memory_notify arg; 392 393 arg.start_pfn = pfn; 394 arg.nr_pages = nr_pages; 395 arg.status_change_nid = -1; 396 397 nid = page_to_nid(pfn_to_page(pfn)); 398 if (node_present_pages(nid) == 0) 399 arg.status_change_nid = nid; 400 401 ret = memory_notify(MEM_GOING_ONLINE, &arg); 402 ret = notifier_to_errno(ret); 403 if (ret) { 404 memory_notify(MEM_CANCEL_ONLINE, &arg); 405 return ret; 406 } 407 /* 408 * This doesn't need a lock to do pfn_to_page(). 409 * The section can't be removed here because of the 410 * memory_block->state_mutex. 411 */ 412 zone = page_zone(pfn_to_page(pfn)); 413 /* 414 * If this zone is not populated, then it is not in zonelist. 415 * This means the page allocator ignores this zone. 416 * So, zonelist must be updated after online. 417 */ 418 mutex_lock(&zonelists_mutex); 419 if (!populated_zone(zone)) 420 need_zonelists_rebuild = 1; 421 422 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages, 423 online_pages_range); 424 if (ret) { 425 mutex_unlock(&zonelists_mutex); 426 printk(KERN_DEBUG "online_pages %lx at %lx failed\n", 427 nr_pages, pfn); 428 memory_notify(MEM_CANCEL_ONLINE, &arg); 429 return ret; 430 } 431 432 zone->present_pages += onlined_pages; 433 zone->zone_pgdat->node_present_pages += onlined_pages; 434 if (need_zonelists_rebuild) 435 build_all_zonelists(zone); 436 else 437 zone_pcp_update(zone); 438 439 mutex_unlock(&zonelists_mutex); 440 setup_per_zone_wmarks(); 441 calculate_zone_inactive_ratio(zone); 442 if (onlined_pages) { 443 kswapd_run(zone_to_nid(zone)); 444 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); 445 } 446 447 vm_total_pages = nr_free_pagecache_pages(); 448 449 writeback_set_ratelimit(); 450 451 if (onlined_pages) 452 memory_notify(MEM_ONLINE, &arg); 453 454 return 0; 455} 456#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 457 458/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 459static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) 460{ 461 struct pglist_data *pgdat; 462 unsigned long zones_size[MAX_NR_ZONES] = {0}; 463 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 464 unsigned long start_pfn = start >> PAGE_SHIFT; 465 466 pgdat = arch_alloc_nodedata(nid); 467 if (!pgdat) 468 return NULL; 469 470 arch_refresh_nodedata(nid, pgdat); 471 472 /* we can use NODE_DATA(nid) from here */ 473 474 /* init node's zones as empty zones, we don't have any present pages.*/ 475 free_area_init_node(nid, zones_size, start_pfn, zholes_size); 476 477 return pgdat; 478} 479 480static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 481{ 482 arch_refresh_nodedata(nid, NULL); 483 arch_free_nodedata(pgdat); 484 return; 485} 486 487 488/* 489 * called by cpu_up() to online a node without onlined memory. 490 */ 491int mem_online_node(int nid) 492{ 493 pg_data_t *pgdat; 494 int ret; 495 496 lock_system_sleep(); 497 pgdat = hotadd_new_pgdat(nid, 0); 498 if (pgdat) { 499 ret = -ENOMEM; 500 goto out; 501 } 502 node_set_online(nid); 503 ret = register_one_node(nid); 504 BUG_ON(ret); 505 506out: 507 unlock_system_sleep(); 508 return ret; 509} 510 511/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 512int __ref add_memory(int nid, u64 start, u64 size) 513{ 514 pg_data_t *pgdat = NULL; 515 int new_pgdat = 0; 516 struct resource *res; 517 int ret; 518 519 lock_system_sleep(); 520 521 res = register_memory_resource(start, size); 522 ret = -EEXIST; 523 if (!res) 524 goto out; 525 526 if (!node_online(nid)) { 527 pgdat = hotadd_new_pgdat(nid, start); 528 ret = -ENOMEM; 529 if (!pgdat) 530 goto out; 531 new_pgdat = 1; 532 } 533 534 /* call arch's memory hotadd */ 535 ret = arch_add_memory(nid, start, size); 536 537 if (ret < 0) 538 goto error; 539 540 /* we online node here. we can't roll back from here. */ 541 node_set_online(nid); 542 543 if (new_pgdat) { 544 ret = register_one_node(nid); 545 /* 546 * If sysfs file of new node can't create, cpu on the node 547 * can't be hot-added. There is no rollback way now. 548 * So, check by BUG_ON() to catch it reluctantly.. 549 */ 550 BUG_ON(ret); 551 } 552 553 /* create new memmap entry */ 554 firmware_map_add_hotplug(start, start + size, "System RAM"); 555 556 goto out; 557 558error: 559 /* rollback pgdat allocation and others */ 560 if (new_pgdat) 561 rollback_node_hotadd(nid, pgdat); 562 if (res) 563 release_memory_resource(res); 564 565out: 566 unlock_system_sleep(); 567 return ret; 568} 569EXPORT_SYMBOL_GPL(add_memory); 570 571#ifdef CONFIG_MEMORY_HOTREMOVE 572/* 573 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy 574 * set and the size of the free page is given by page_order(). Using this, 575 * the function determines if the pageblock contains only free pages. 576 * Due to buddy contraints, a free page at least the size of a pageblock will 577 * be located at the start of the pageblock 578 */ 579static inline int pageblock_free(struct page *page) 580{ 581 return PageBuddy(page) && page_order(page) >= pageblock_order; 582} 583 584/* Return the start of the next active pageblock after a given page */ 585static struct page *next_active_pageblock(struct page *page) 586{ 587 /* Ensure the starting page is pageblock-aligned */ 588 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1)); 589 590 /* If the entire pageblock is free, move to the end of free page */ 591 if (pageblock_free(page)) { 592 int order; 593 /* be careful. we don't have locks, page_order can be changed.*/ 594 order = page_order(page); 595 if ((order < MAX_ORDER) && (order >= pageblock_order)) 596 return page + (1 << order); 597 } 598 599 return page + pageblock_nr_pages; 600} 601 602/* Checks if this range of memory is likely to be hot-removable. */ 603int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) 604{ 605 int type; 606 struct page *page = pfn_to_page(start_pfn); 607 struct page *end_page = page + nr_pages; 608 609 /* Check the starting page of each pageblock within the range */ 610 for (; page < end_page; page = next_active_pageblock(page)) { 611 type = get_pageblock_migratetype(page); 612 613 /* 614 * A pageblock containing MOVABLE or free pages is considered 615 * removable 616 */ 617 if (type != MIGRATE_MOVABLE && !pageblock_free(page)) 618 return 0; 619 620 /* 621 * A pageblock starting with a PageReserved page is not 622 * considered removable. 623 */ 624 if (PageReserved(page)) 625 return 0; 626 } 627 628 /* All pageblocks in the memory block are likely to be hot-removable */ 629 return 1; 630} 631 632/* 633 * Confirm all pages in a range [start, end) is belongs to the same zone. 634 */ 635static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 636{ 637 unsigned long pfn; 638 struct zone *zone = NULL; 639 struct page *page; 640 int i; 641 for (pfn = start_pfn; 642 pfn < end_pfn; 643 pfn += MAX_ORDER_NR_PAGES) { 644 i = 0; 645 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 646 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 647 i++; 648 if (i == MAX_ORDER_NR_PAGES) 649 continue; 650 page = pfn_to_page(pfn + i); 651 if (zone && page_zone(page) != zone) 652 return 0; 653 zone = page_zone(page); 654 } 655 return 1; 656} 657 658/* 659 * Scanning pfn is much easier than scanning lru list. 660 * Scan pfn from start to end and Find LRU page. 661 */ 662unsigned long scan_lru_pages(unsigned long start, unsigned long end) 663{ 664 unsigned long pfn; 665 struct page *page; 666 for (pfn = start; pfn < end; pfn++) { 667 if (pfn_valid(pfn)) { 668 page = pfn_to_page(pfn); 669 if (PageLRU(page)) 670 return pfn; 671 } 672 } 673 return 0; 674} 675 676static struct page * 677hotremove_migrate_alloc(struct page *page, unsigned long private, int **x) 678{ 679 /* This should be improooooved!! */ 680 return alloc_page(GFP_HIGHUSER_MOVABLE); 681} 682 683#define NR_OFFLINE_AT_ONCE_PAGES (256) 684static int 685do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 686{ 687 unsigned long pfn; 688 struct page *page; 689 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 690 int not_managed = 0; 691 int ret = 0; 692 LIST_HEAD(source); 693 694 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 695 if (!pfn_valid(pfn)) 696 continue; 697 page = pfn_to_page(pfn); 698 if (!page_count(page)) 699 continue; 700 /* 701 * We can skip free pages. And we can only deal with pages on 702 * LRU. 703 */ 704 ret = isolate_lru_page(page); 705 if (!ret) { /* Success */ 706 list_add_tail(&page->lru, &source); 707 move_pages--; 708 inc_zone_page_state(page, NR_ISOLATED_ANON + 709 page_is_file_cache(page)); 710 711 } else { 712 /* Becasue we don't have big zone->lock. we should 713 check this again here. */ 714 if (page_count(page)) 715 not_managed++; 716#ifdef CONFIG_DEBUG_VM 717 printk(KERN_ALERT "removing pfn %lx from LRU failed\n", 718 pfn); 719 dump_page(page); 720#endif 721 } 722 } 723 ret = -EBUSY; 724 if (not_managed) { 725 if (!list_empty(&source)) 726 putback_lru_pages(&source); 727 goto out; 728 } 729 ret = 0; 730 if (list_empty(&source)) 731 goto out; 732 /* this function returns # of failed pages */ 733 ret = migrate_pages(&source, hotremove_migrate_alloc, 0, 1); 734 if (ret) 735 putback_lru_pages(&source); 736 737out: 738 return ret; 739} 740 741/* 742 * remove from free_area[] and mark all as Reserved. 743 */ 744static int 745offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 746 void *data) 747{ 748 __offline_isolated_pages(start, start + nr_pages); 749 return 0; 750} 751 752static void 753offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 754{ 755 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL, 756 offline_isolated_pages_cb); 757} 758 759/* 760 * Check all pages in range, recoreded as memory resource, are isolated. 761 */ 762static int 763check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 764 void *data) 765{ 766 int ret; 767 long offlined = *(long *)data; 768 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 769 offlined = nr_pages; 770 if (!ret) 771 *(long *)data += offlined; 772 return ret; 773} 774 775static long 776check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 777{ 778 long offlined = 0; 779 int ret; 780 781 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined, 782 check_pages_isolated_cb); 783 if (ret < 0) 784 offlined = (long)ret; 785 return offlined; 786} 787 788static int offline_pages(unsigned long start_pfn, 789 unsigned long end_pfn, unsigned long timeout) 790{ 791 unsigned long pfn, nr_pages, expire; 792 long offlined_pages; 793 int ret, drain, retry_max, node; 794 struct zone *zone; 795 struct memory_notify arg; 796 797 BUG_ON(start_pfn >= end_pfn); 798 /* at least, alignment against pageblock is necessary */ 799 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 800 return -EINVAL; 801 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 802 return -EINVAL; 803 /* This makes hotplug much easier...and readable. 804 we assume this for now. .*/ 805 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 806 return -EINVAL; 807 808 lock_system_sleep(); 809 810 zone = page_zone(pfn_to_page(start_pfn)); 811 node = zone_to_nid(zone); 812 nr_pages = end_pfn - start_pfn; 813 814 /* set above range as isolated */ 815 ret = start_isolate_page_range(start_pfn, end_pfn); 816 if (ret) 817 goto out; 818 819 arg.start_pfn = start_pfn; 820 arg.nr_pages = nr_pages; 821 arg.status_change_nid = -1; 822 if (nr_pages >= node_present_pages(node)) 823 arg.status_change_nid = node; 824 825 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 826 ret = notifier_to_errno(ret); 827 if (ret) 828 goto failed_removal; 829 830 pfn = start_pfn; 831 expire = jiffies + timeout; 832 drain = 0; 833 retry_max = 5; 834repeat: 835 /* start memory hot removal */ 836 ret = -EAGAIN; 837 if (time_after(jiffies, expire)) 838 goto failed_removal; 839 ret = -EINTR; 840 if (signal_pending(current)) 841 goto failed_removal; 842 ret = 0; 843 if (drain) { 844 lru_add_drain_all(); 845 cond_resched(); 846 drain_all_pages(); 847 } 848 849 pfn = scan_lru_pages(start_pfn, end_pfn); 850 if (pfn) { /* We have page on LRU */ 851 ret = do_migrate_range(pfn, end_pfn); 852 if (!ret) { 853 drain = 1; 854 goto repeat; 855 } else { 856 if (ret < 0) 857 if (--retry_max == 0) 858 goto failed_removal; 859 yield(); 860 drain = 1; 861 goto repeat; 862 } 863 } 864 /* drain all zone's lru pagevec, this is asyncronous... */ 865 lru_add_drain_all(); 866 yield(); 867 /* drain pcp pages , this is synchrouns. */ 868 drain_all_pages(); 869 /* check again */ 870 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 871 if (offlined_pages < 0) { 872 ret = -EBUSY; 873 goto failed_removal; 874 } 875 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 876 /* Ok, all of our target is islaoted. 877 We cannot do rollback at this point. */ 878 offline_isolated_pages(start_pfn, end_pfn); 879 /* reset pagetype flags and makes migrate type to be MOVABLE */ 880 undo_isolate_page_range(start_pfn, end_pfn); 881 /* removal success */ 882 zone->present_pages -= offlined_pages; 883 zone->zone_pgdat->node_present_pages -= offlined_pages; 884 totalram_pages -= offlined_pages; 885 886 setup_per_zone_wmarks(); 887 calculate_zone_inactive_ratio(zone); 888 if (!node_present_pages(node)) { 889 node_clear_state(node, N_HIGH_MEMORY); 890 kswapd_stop(node); 891 } 892 893 vm_total_pages = nr_free_pagecache_pages(); 894 writeback_set_ratelimit(); 895 896 memory_notify(MEM_OFFLINE, &arg); 897 unlock_system_sleep(); 898 return 0; 899 900failed_removal: 901 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 902 start_pfn, end_pfn); 903 memory_notify(MEM_CANCEL_OFFLINE, &arg); 904 /* pushback to free area */ 905 undo_isolate_page_range(start_pfn, end_pfn); 906 907out: 908 unlock_system_sleep(); 909 return ret; 910} 911 912int remove_memory(u64 start, u64 size) 913{ 914 unsigned long start_pfn, end_pfn; 915 916 start_pfn = PFN_DOWN(start); 917 end_pfn = start_pfn + PFN_DOWN(size); 918 return offline_pages(start_pfn, end_pfn, 120 * HZ); 919} 920#else 921int remove_memory(u64 start, u64 size) 922{ 923 return -EINVAL; 924} 925#endif /* CONFIG_MEMORY_HOTREMOVE */ 926EXPORT_SYMBOL_GPL(remove_memory); 927