memory_hotplug.c revision 809c444977adb7313e0612e9e3af4b73ba3f5746
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 struct page *page = pfn_to_page(start_pfn); 606 struct page *end_page = page + nr_pages; 607 608 /* Check the starting page of each pageblock within the range */ 609 for (; page < end_page; page = next_active_pageblock(page)) { 610 if (!is_pageblock_removable_nolock(page)) 611 return 0; 612 cond_resched(); 613 } 614 615 /* All pageblocks in the memory block are likely to be hot-removable */ 616 return 1; 617} 618 619/* 620 * Confirm all pages in a range [start, end) is belongs to the same zone. 621 */ 622static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 623{ 624 unsigned long pfn; 625 struct zone *zone = NULL; 626 struct page *page; 627 int i; 628 for (pfn = start_pfn; 629 pfn < end_pfn; 630 pfn += MAX_ORDER_NR_PAGES) { 631 i = 0; 632 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 633 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 634 i++; 635 if (i == MAX_ORDER_NR_PAGES) 636 continue; 637 page = pfn_to_page(pfn + i); 638 if (zone && page_zone(page) != zone) 639 return 0; 640 zone = page_zone(page); 641 } 642 return 1; 643} 644 645/* 646 * Scanning pfn is much easier than scanning lru list. 647 * Scan pfn from start to end and Find LRU page. 648 */ 649static unsigned long scan_lru_pages(unsigned long start, unsigned long end) 650{ 651 unsigned long pfn; 652 struct page *page; 653 for (pfn = start; pfn < end; pfn++) { 654 if (pfn_valid(pfn)) { 655 page = pfn_to_page(pfn); 656 if (PageLRU(page)) 657 return pfn; 658 } 659 } 660 return 0; 661} 662 663static struct page * 664hotremove_migrate_alloc(struct page *page, unsigned long private, int **x) 665{ 666 /* This should be improooooved!! */ 667 return alloc_page(GFP_HIGHUSER_MOVABLE); 668} 669 670#define NR_OFFLINE_AT_ONCE_PAGES (256) 671static int 672do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 673{ 674 unsigned long pfn; 675 struct page *page; 676 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 677 int not_managed = 0; 678 int ret = 0; 679 LIST_HEAD(source); 680 681 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 682 if (!pfn_valid(pfn)) 683 continue; 684 page = pfn_to_page(pfn); 685 if (!page_count(page)) 686 continue; 687 /* 688 * We can skip free pages. And we can only deal with pages on 689 * LRU. 690 */ 691 ret = isolate_lru_page(page); 692 if (!ret) { /* Success */ 693 list_add_tail(&page->lru, &source); 694 move_pages--; 695 inc_zone_page_state(page, NR_ISOLATED_ANON + 696 page_is_file_cache(page)); 697 698 } else { 699#ifdef CONFIG_DEBUG_VM 700 printk(KERN_ALERT "removing pfn %lx from LRU failed\n", 701 pfn); 702 dump_page(page); 703#endif 704 /* Becasue we don't have big zone->lock. we should 705 check this again here. */ 706 if (page_count(page)) { 707 not_managed++; 708 break; 709 } 710 } 711 } 712 ret = -EBUSY; 713 if (not_managed) { 714 if (!list_empty(&source)) 715 putback_lru_pages(&source); 716 goto out; 717 } 718 ret = 0; 719 if (list_empty(&source)) 720 goto out; 721 /* this function returns # of failed pages */ 722 ret = migrate_pages(&source, hotremove_migrate_alloc, 0, 1); 723 if (ret) 724 putback_lru_pages(&source); 725 726out: 727 return ret; 728} 729 730/* 731 * remove from free_area[] and mark all as Reserved. 732 */ 733static int 734offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 735 void *data) 736{ 737 __offline_isolated_pages(start, start + nr_pages); 738 return 0; 739} 740 741static void 742offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 743{ 744 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL, 745 offline_isolated_pages_cb); 746} 747 748/* 749 * Check all pages in range, recoreded as memory resource, are isolated. 750 */ 751static int 752check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 753 void *data) 754{ 755 int ret; 756 long offlined = *(long *)data; 757 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 758 offlined = nr_pages; 759 if (!ret) 760 *(long *)data += offlined; 761 return ret; 762} 763 764static long 765check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 766{ 767 long offlined = 0; 768 int ret; 769 770 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined, 771 check_pages_isolated_cb); 772 if (ret < 0) 773 offlined = (long)ret; 774 return offlined; 775} 776 777static int offline_pages(unsigned long start_pfn, 778 unsigned long end_pfn, unsigned long timeout) 779{ 780 unsigned long pfn, nr_pages, expire; 781 long offlined_pages; 782 int ret, drain, retry_max, node; 783 struct zone *zone; 784 struct memory_notify arg; 785 786 BUG_ON(start_pfn >= end_pfn); 787 /* at least, alignment against pageblock is necessary */ 788 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 789 return -EINVAL; 790 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 791 return -EINVAL; 792 /* This makes hotplug much easier...and readable. 793 we assume this for now. .*/ 794 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 795 return -EINVAL; 796 797 lock_system_sleep(); 798 799 zone = page_zone(pfn_to_page(start_pfn)); 800 node = zone_to_nid(zone); 801 nr_pages = end_pfn - start_pfn; 802 803 /* set above range as isolated */ 804 ret = start_isolate_page_range(start_pfn, end_pfn); 805 if (ret) 806 goto out; 807 808 arg.start_pfn = start_pfn; 809 arg.nr_pages = nr_pages; 810 arg.status_change_nid = -1; 811 if (nr_pages >= node_present_pages(node)) 812 arg.status_change_nid = node; 813 814 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 815 ret = notifier_to_errno(ret); 816 if (ret) 817 goto failed_removal; 818 819 pfn = start_pfn; 820 expire = jiffies + timeout; 821 drain = 0; 822 retry_max = 5; 823repeat: 824 /* start memory hot removal */ 825 ret = -EAGAIN; 826 if (time_after(jiffies, expire)) 827 goto failed_removal; 828 ret = -EINTR; 829 if (signal_pending(current)) 830 goto failed_removal; 831 ret = 0; 832 if (drain) { 833 lru_add_drain_all(); 834 cond_resched(); 835 drain_all_pages(); 836 } 837 838 pfn = scan_lru_pages(start_pfn, end_pfn); 839 if (pfn) { /* We have page on LRU */ 840 ret = do_migrate_range(pfn, end_pfn); 841 if (!ret) { 842 drain = 1; 843 goto repeat; 844 } else { 845 if (ret < 0) 846 if (--retry_max == 0) 847 goto failed_removal; 848 yield(); 849 drain = 1; 850 goto repeat; 851 } 852 } 853 /* drain all zone's lru pagevec, this is asyncronous... */ 854 lru_add_drain_all(); 855 yield(); 856 /* drain pcp pages , this is synchrouns. */ 857 drain_all_pages(); 858 /* check again */ 859 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 860 if (offlined_pages < 0) { 861 ret = -EBUSY; 862 goto failed_removal; 863 } 864 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 865 /* Ok, all of our target is islaoted. 866 We cannot do rollback at this point. */ 867 offline_isolated_pages(start_pfn, end_pfn); 868 /* reset pagetype flags and makes migrate type to be MOVABLE */ 869 undo_isolate_page_range(start_pfn, end_pfn); 870 /* removal success */ 871 zone->present_pages -= offlined_pages; 872 zone->zone_pgdat->node_present_pages -= offlined_pages; 873 totalram_pages -= offlined_pages; 874 875 setup_per_zone_wmarks(); 876 calculate_zone_inactive_ratio(zone); 877 if (!node_present_pages(node)) { 878 node_clear_state(node, N_HIGH_MEMORY); 879 kswapd_stop(node); 880 } 881 882 vm_total_pages = nr_free_pagecache_pages(); 883 writeback_set_ratelimit(); 884 885 memory_notify(MEM_OFFLINE, &arg); 886 unlock_system_sleep(); 887 return 0; 888 889failed_removal: 890 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 891 start_pfn, end_pfn); 892 memory_notify(MEM_CANCEL_OFFLINE, &arg); 893 /* pushback to free area */ 894 undo_isolate_page_range(start_pfn, end_pfn); 895 896out: 897 unlock_system_sleep(); 898 return ret; 899} 900 901int remove_memory(u64 start, u64 size) 902{ 903 unsigned long start_pfn, end_pfn; 904 905 start_pfn = PFN_DOWN(start); 906 end_pfn = start_pfn + PFN_DOWN(size); 907 return offline_pages(start_pfn, end_pfn, 120 * HZ); 908} 909#else 910int remove_memory(u64 start, u64 size) 911{ 912 return -EINVAL; 913} 914#endif /* CONFIG_MEMORY_HOTREMOVE */ 915EXPORT_SYMBOL_GPL(remove_memory); 916