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 DEFINE_MUTEX(mem_hotplug_mutex); 38 39 void lock_memory_hotplug(void) 40 { 41 mutex_lock(&mem_hotplug_mutex); 42 43 /* for exclusive hibernation if CONFIG_HIBERNATION=y */ 44 lock_system_sleep(); 45 } 46 47 void unlock_memory_hotplug(void) 48 { 49 unlock_system_sleep(); 50 mutex_unlock(&mem_hotplug_mutex); 51 } 52 53 54 /* add this memory to iomem resource */ 55 static struct resource *register_memory_resource(u64 start, u64 size) 56 { 57 struct resource *res; 58 res = kzalloc(sizeof(struct resource), GFP_KERNEL); 59 BUG_ON(!res); 60 61 res->name = "System RAM"; 62 res->start = start; 63 res->end = start + size - 1; 64 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; 65 if (request_resource(&iomem_resource, res) < 0) { 66 printk("System RAM resource %llx - %llx cannot be added\n", 67 (unsigned long long)res->start, (unsigned long long)res->end); 68 kfree(res); 69 res = NULL; 70 } 71 return res; 72 } 73 74 static void release_memory_resource(struct resource *res) 75 { 76 if (!res) 77 return; 78 release_resource(res); 79 kfree(res); 80 return; 81 } 82 83 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 84 #ifndef CONFIG_SPARSEMEM_VMEMMAP 85 static void get_page_bootmem(unsigned long info, struct page *page, 86 unsigned long type) 87 { 88 page->lru.next = (struct list_head *) type; 89 SetPagePrivate(page); 90 set_page_private(page, info); 91 atomic_inc(&page->_count); 92 } 93 94 /* reference to __meminit __free_pages_bootmem is valid 95 * so use __ref to tell modpost not to generate a warning */ 96 void __ref put_page_bootmem(struct page *page) 97 { 98 unsigned long type; 99 100 type = (unsigned long) page->lru.next; 101 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || 102 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE); 103 104 if (atomic_dec_return(&page->_count) == 1) { 105 ClearPagePrivate(page); 106 set_page_private(page, 0); 107 INIT_LIST_HEAD(&page->lru); 108 __free_pages_bootmem(page, 0); 109 } 110 111 } 112 113 static void register_page_bootmem_info_section(unsigned long start_pfn) 114 { 115 unsigned long *usemap, mapsize, section_nr, i; 116 struct mem_section *ms; 117 struct page *page, *memmap; 118 119 if (!pfn_valid(start_pfn)) 120 return; 121 122 section_nr = pfn_to_section_nr(start_pfn); 123 ms = __nr_to_section(section_nr); 124 125 /* Get section's memmap address */ 126 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); 127 128 /* 129 * Get page for the memmap's phys address 130 * XXX: need more consideration for sparse_vmemmap... 131 */ 132 page = virt_to_page(memmap); 133 mapsize = sizeof(struct page) * PAGES_PER_SECTION; 134 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT; 135 136 /* remember memmap's page */ 137 for (i = 0; i < mapsize; i++, page++) 138 get_page_bootmem(section_nr, page, SECTION_INFO); 139 140 usemap = __nr_to_section(section_nr)->pageblock_flags; 141 page = virt_to_page(usemap); 142 143 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; 144 145 for (i = 0; i < mapsize; i++, page++) 146 get_page_bootmem(section_nr, page, MIX_SECTION_INFO); 147 148 } 149 150 void register_page_bootmem_info_node(struct pglist_data *pgdat) 151 { 152 unsigned long i, pfn, end_pfn, nr_pages; 153 int node = pgdat->node_id; 154 struct page *page; 155 struct zone *zone; 156 157 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT; 158 page = virt_to_page(pgdat); 159 160 for (i = 0; i < nr_pages; i++, page++) 161 get_page_bootmem(node, page, NODE_INFO); 162 163 zone = &pgdat->node_zones[0]; 164 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) { 165 if (zone->wait_table) { 166 nr_pages = zone->wait_table_hash_nr_entries 167 * sizeof(wait_queue_head_t); 168 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT; 169 page = virt_to_page(zone->wait_table); 170 171 for (i = 0; i < nr_pages; i++, page++) 172 get_page_bootmem(node, page, NODE_INFO); 173 } 174 } 175 176 pfn = pgdat->node_start_pfn; 177 end_pfn = pfn + pgdat->node_spanned_pages; 178 179 /* register_section info */ 180 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) 181 register_page_bootmem_info_section(pfn); 182 183 } 184 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */ 185 186 static void grow_zone_span(struct zone *zone, unsigned long start_pfn, 187 unsigned long end_pfn) 188 { 189 unsigned long old_zone_end_pfn; 190 191 zone_span_writelock(zone); 192 193 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; 194 if (start_pfn < zone->zone_start_pfn) 195 zone->zone_start_pfn = start_pfn; 196 197 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - 198 zone->zone_start_pfn; 199 200 zone_span_writeunlock(zone); 201 } 202 203 static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn, 204 unsigned long end_pfn) 205 { 206 unsigned long old_pgdat_end_pfn = 207 pgdat->node_start_pfn + pgdat->node_spanned_pages; 208 209 if (start_pfn < pgdat->node_start_pfn) 210 pgdat->node_start_pfn = start_pfn; 211 212 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - 213 pgdat->node_start_pfn; 214 } 215 216 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn) 217 { 218 struct pglist_data *pgdat = zone->zone_pgdat; 219 int nr_pages = PAGES_PER_SECTION; 220 int nid = pgdat->node_id; 221 int zone_type; 222 unsigned long flags; 223 224 zone_type = zone - pgdat->node_zones; 225 if (!zone->wait_table) { 226 int ret; 227 228 ret = init_currently_empty_zone(zone, phys_start_pfn, 229 nr_pages, MEMMAP_HOTPLUG); 230 if (ret) 231 return ret; 232 } 233 pgdat_resize_lock(zone->zone_pgdat, &flags); 234 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages); 235 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn, 236 phys_start_pfn + nr_pages); 237 pgdat_resize_unlock(zone->zone_pgdat, &flags); 238 memmap_init_zone(nr_pages, nid, zone_type, 239 phys_start_pfn, MEMMAP_HOTPLUG); 240 return 0; 241 } 242 243 static int __meminit __add_section(int nid, struct zone *zone, 244 unsigned long phys_start_pfn) 245 { 246 int nr_pages = PAGES_PER_SECTION; 247 int ret; 248 249 if (pfn_valid(phys_start_pfn)) 250 return -EEXIST; 251 252 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); 253 254 if (ret < 0) 255 return ret; 256 257 ret = __add_zone(zone, phys_start_pfn); 258 259 if (ret < 0) 260 return ret; 261 262 return register_new_memory(nid, __pfn_to_section(phys_start_pfn)); 263 } 264 265 #ifdef CONFIG_SPARSEMEM_VMEMMAP 266 static int __remove_section(struct zone *zone, struct mem_section *ms) 267 { 268 /* 269 * XXX: Freeing memmap with vmemmap is not implement yet. 270 * This should be removed later. 271 */ 272 return -EBUSY; 273 } 274 #else 275 static int __remove_section(struct zone *zone, struct mem_section *ms) 276 { 277 unsigned long flags; 278 struct pglist_data *pgdat = zone->zone_pgdat; 279 int ret = -EINVAL; 280 281 if (!valid_section(ms)) 282 return ret; 283 284 ret = unregister_memory_section(ms); 285 if (ret) 286 return ret; 287 288 pgdat_resize_lock(pgdat, &flags); 289 sparse_remove_one_section(zone, ms); 290 pgdat_resize_unlock(pgdat, &flags); 291 return 0; 292 } 293 #endif 294 295 /* 296 * Reasonably generic function for adding memory. It is 297 * expected that archs that support memory hotplug will 298 * call this function after deciding the zone to which to 299 * add the new pages. 300 */ 301 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn, 302 unsigned long nr_pages) 303 { 304 unsigned long i; 305 int err = 0; 306 int start_sec, end_sec; 307 /* during initialize mem_map, align hot-added range to section */ 308 start_sec = pfn_to_section_nr(phys_start_pfn); 309 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); 310 311 for (i = start_sec; i <= end_sec; i++) { 312 err = __add_section(nid, zone, i << PFN_SECTION_SHIFT); 313 314 /* 315 * EEXIST is finally dealt with by ioresource collision 316 * check. see add_memory() => register_memory_resource() 317 * Warning will be printed if there is collision. 318 */ 319 if (err && (err != -EEXIST)) 320 break; 321 err = 0; 322 } 323 324 return err; 325 } 326 EXPORT_SYMBOL_GPL(__add_pages); 327 328 /** 329 * __remove_pages() - remove sections of pages from a zone 330 * @zone: zone from which pages need to be removed 331 * @phys_start_pfn: starting pageframe (must be aligned to start of a section) 332 * @nr_pages: number of pages to remove (must be multiple of section size) 333 * 334 * Generic helper function to remove section mappings and sysfs entries 335 * for the section of the memory we are removing. Caller needs to make 336 * sure that pages are marked reserved and zones are adjust properly by 337 * calling offline_pages(). 338 */ 339 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, 340 unsigned long nr_pages) 341 { 342 unsigned long i, ret = 0; 343 int sections_to_remove; 344 345 /* 346 * We can only remove entire sections 347 */ 348 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); 349 BUG_ON(nr_pages % PAGES_PER_SECTION); 350 351 sections_to_remove = nr_pages / PAGES_PER_SECTION; 352 for (i = 0; i < sections_to_remove; i++) { 353 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; 354 release_mem_region(pfn << PAGE_SHIFT, 355 PAGES_PER_SECTION << PAGE_SHIFT); 356 ret = __remove_section(zone, __pfn_to_section(pfn)); 357 if (ret) 358 break; 359 } 360 return ret; 361 } 362 EXPORT_SYMBOL_GPL(__remove_pages); 363 364 void online_page(struct page *page) 365 { 366 unsigned long pfn = page_to_pfn(page); 367 368 totalram_pages++; 369 if (pfn >= num_physpages) 370 num_physpages = pfn + 1; 371 372 #ifdef CONFIG_HIGHMEM 373 if (PageHighMem(page)) 374 totalhigh_pages++; 375 #endif 376 377 #ifdef CONFIG_FLATMEM 378 max_mapnr = max(page_to_pfn(page), max_mapnr); 379 #endif 380 381 ClearPageReserved(page); 382 init_page_count(page); 383 __free_page(page); 384 } 385 386 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, 387 void *arg) 388 { 389 unsigned long i; 390 unsigned long onlined_pages = *(unsigned long *)arg; 391 struct page *page; 392 if (PageReserved(pfn_to_page(start_pfn))) 393 for (i = 0; i < nr_pages; i++) { 394 page = pfn_to_page(start_pfn + i); 395 online_page(page); 396 onlined_pages++; 397 } 398 *(unsigned long *)arg = onlined_pages; 399 return 0; 400 } 401 402 403 int online_pages(unsigned long pfn, unsigned long nr_pages) 404 { 405 unsigned long onlined_pages = 0; 406 struct zone *zone; 407 int need_zonelists_rebuild = 0; 408 int nid; 409 int ret; 410 struct memory_notify arg; 411 412 lock_memory_hotplug(); 413 arg.start_pfn = pfn; 414 arg.nr_pages = nr_pages; 415 arg.status_change_nid = -1; 416 417 nid = page_to_nid(pfn_to_page(pfn)); 418 if (node_present_pages(nid) == 0) 419 arg.status_change_nid = nid; 420 421 ret = memory_notify(MEM_GOING_ONLINE, &arg); 422 ret = notifier_to_errno(ret); 423 if (ret) { 424 memory_notify(MEM_CANCEL_ONLINE, &arg); 425 unlock_memory_hotplug(); 426 return ret; 427 } 428 /* 429 * This doesn't need a lock to do pfn_to_page(). 430 * The section can't be removed here because of the 431 * memory_block->state_mutex. 432 */ 433 zone = page_zone(pfn_to_page(pfn)); 434 /* 435 * If this zone is not populated, then it is not in zonelist. 436 * This means the page allocator ignores this zone. 437 * So, zonelist must be updated after online. 438 */ 439 mutex_lock(&zonelists_mutex); 440 if (!populated_zone(zone)) 441 need_zonelists_rebuild = 1; 442 443 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages, 444 online_pages_range); 445 if (ret) { 446 mutex_unlock(&zonelists_mutex); 447 printk(KERN_DEBUG "online_pages %lx at %lx failed\n", 448 nr_pages, pfn); 449 memory_notify(MEM_CANCEL_ONLINE, &arg); 450 unlock_memory_hotplug(); 451 return ret; 452 } 453 454 zone->present_pages += onlined_pages; 455 zone->zone_pgdat->node_present_pages += onlined_pages; 456 if (need_zonelists_rebuild) 457 build_all_zonelists(zone); 458 else 459 zone_pcp_update(zone); 460 461 mutex_unlock(&zonelists_mutex); 462 setup_per_zone_wmarks(); 463 calculate_zone_inactive_ratio(zone); 464 if (onlined_pages) { 465 kswapd_run(zone_to_nid(zone)); 466 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); 467 } 468 469 vm_total_pages = nr_free_pagecache_pages(); 470 471 writeback_set_ratelimit(); 472 473 if (onlined_pages) 474 memory_notify(MEM_ONLINE, &arg); 475 unlock_memory_hotplug(); 476 477 return 0; 478 } 479 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 480 481 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 482 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) 483 { 484 struct pglist_data *pgdat; 485 unsigned long zones_size[MAX_NR_ZONES] = {0}; 486 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 487 unsigned long start_pfn = start >> PAGE_SHIFT; 488 489 pgdat = arch_alloc_nodedata(nid); 490 if (!pgdat) 491 return NULL; 492 493 arch_refresh_nodedata(nid, pgdat); 494 495 /* we can use NODE_DATA(nid) from here */ 496 497 /* init node's zones as empty zones, we don't have any present pages.*/ 498 free_area_init_node(nid, zones_size, start_pfn, zholes_size); 499 500 return pgdat; 501 } 502 503 static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 504 { 505 arch_refresh_nodedata(nid, NULL); 506 arch_free_nodedata(pgdat); 507 return; 508 } 509 510 511 /* 512 * called by cpu_up() to online a node without onlined memory. 513 */ 514 int mem_online_node(int nid) 515 { 516 pg_data_t *pgdat; 517 int ret; 518 519 lock_memory_hotplug(); 520 pgdat = hotadd_new_pgdat(nid, 0); 521 if (pgdat) { 522 ret = -ENOMEM; 523 goto out; 524 } 525 node_set_online(nid); 526 ret = register_one_node(nid); 527 BUG_ON(ret); 528 529 out: 530 unlock_memory_hotplug(); 531 return ret; 532 } 533 534 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 535 int __ref add_memory(int nid, u64 start, u64 size) 536 { 537 pg_data_t *pgdat = NULL; 538 int new_pgdat = 0; 539 struct resource *res; 540 int ret; 541 542 lock_memory_hotplug(); 543 544 res = register_memory_resource(start, size); 545 ret = -EEXIST; 546 if (!res) 547 goto out; 548 549 if (!node_online(nid)) { 550 pgdat = hotadd_new_pgdat(nid, start); 551 ret = -ENOMEM; 552 if (!pgdat) 553 goto out; 554 new_pgdat = 1; 555 } 556 557 /* call arch's memory hotadd */ 558 ret = arch_add_memory(nid, start, size); 559 560 if (ret < 0) 561 goto error; 562 563 /* we online node here. we can't roll back from here. */ 564 node_set_online(nid); 565 566 if (new_pgdat) { 567 ret = register_one_node(nid); 568 /* 569 * If sysfs file of new node can't create, cpu on the node 570 * can't be hot-added. There is no rollback way now. 571 * So, check by BUG_ON() to catch it reluctantly.. 572 */ 573 BUG_ON(ret); 574 } 575 576 /* create new memmap entry */ 577 firmware_map_add_hotplug(start, start + size, "System RAM"); 578 579 goto out; 580 581 error: 582 /* rollback pgdat allocation and others */ 583 if (new_pgdat) 584 rollback_node_hotadd(nid, pgdat); 585 if (res) 586 release_memory_resource(res); 587 588 out: 589 unlock_memory_hotplug(); 590 return ret; 591 } 592 EXPORT_SYMBOL_GPL(add_memory); 593 594 #ifdef CONFIG_MEMORY_HOTREMOVE 595 /* 596 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy 597 * set and the size of the free page is given by page_order(). Using this, 598 * the function determines if the pageblock contains only free pages. 599 * Due to buddy contraints, a free page at least the size of a pageblock will 600 * be located at the start of the pageblock 601 */ 602 static inline int pageblock_free(struct page *page) 603 { 604 return PageBuddy(page) && page_order(page) >= pageblock_order; 605 } 606 607 /* Return the start of the next active pageblock after a given page */ 608 static struct page *next_active_pageblock(struct page *page) 609 { 610 /* Ensure the starting page is pageblock-aligned */ 611 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1)); 612 613 /* If the entire pageblock is free, move to the end of free page */ 614 if (pageblock_free(page)) { 615 int order; 616 /* be careful. we don't have locks, page_order can be changed.*/ 617 order = page_order(page); 618 if ((order < MAX_ORDER) && (order >= pageblock_order)) 619 return page + (1 << order); 620 } 621 622 return page + pageblock_nr_pages; 623 } 624 625 /* Checks if this range of memory is likely to be hot-removable. */ 626 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) 627 { 628 struct page *page = pfn_to_page(start_pfn); 629 struct page *end_page = page + nr_pages; 630 631 /* Check the starting page of each pageblock within the range */ 632 for (; page < end_page; page = next_active_pageblock(page)) { 633 if (!is_pageblock_removable_nolock(page)) 634 return 0; 635 cond_resched(); 636 } 637 638 /* All pageblocks in the memory block are likely to be hot-removable */ 639 return 1; 640 } 641 642 /* 643 * Confirm all pages in a range [start, end) is belongs to the same zone. 644 */ 645 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 646 { 647 unsigned long pfn; 648 struct zone *zone = NULL; 649 struct page *page; 650 int i; 651 for (pfn = start_pfn; 652 pfn < end_pfn; 653 pfn += MAX_ORDER_NR_PAGES) { 654 i = 0; 655 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 656 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 657 i++; 658 if (i == MAX_ORDER_NR_PAGES) 659 continue; 660 page = pfn_to_page(pfn + i); 661 if (zone && page_zone(page) != zone) 662 return 0; 663 zone = page_zone(page); 664 } 665 return 1; 666 } 667 668 /* 669 * Scanning pfn is much easier than scanning lru list. 670 * Scan pfn from start to end and Find LRU page. 671 */ 672 static unsigned long scan_lru_pages(unsigned long start, unsigned long end) 673 { 674 unsigned long pfn; 675 struct page *page; 676 for (pfn = start; pfn < end; pfn++) { 677 if (pfn_valid(pfn)) { 678 page = pfn_to_page(pfn); 679 if (PageLRU(page)) 680 return pfn; 681 } 682 } 683 return 0; 684 } 685 686 static struct page * 687 hotremove_migrate_alloc(struct page *page, unsigned long private, int **x) 688 { 689 /* This should be improooooved!! */ 690 return alloc_page(GFP_HIGHUSER_MOVABLE); 691 } 692 693 #define NR_OFFLINE_AT_ONCE_PAGES (256) 694 static int 695 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 696 { 697 unsigned long pfn; 698 struct page *page; 699 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 700 int not_managed = 0; 701 int ret = 0; 702 LIST_HEAD(source); 703 704 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 705 if (!pfn_valid(pfn)) 706 continue; 707 page = pfn_to_page(pfn); 708 if (!page_count(page)) 709 continue; 710 /* 711 * We can skip free pages. And we can only deal with pages on 712 * LRU. 713 */ 714 ret = isolate_lru_page(page); 715 if (!ret) { /* Success */ 716 list_add_tail(&page->lru, &source); 717 move_pages--; 718 inc_zone_page_state(page, NR_ISOLATED_ANON + 719 page_is_file_cache(page)); 720 721 } else { 722 #ifdef CONFIG_DEBUG_VM 723 printk(KERN_ALERT "removing pfn %lx from LRU failed\n", 724 pfn); 725 dump_page(page); 726 #endif 727 /* Becasue we don't have big zone->lock. we should 728 check this again here. */ 729 if (page_count(page)) { 730 not_managed++; 731 ret = -EBUSY; 732 break; 733 } 734 } 735 } 736 if (!list_empty(&source)) { 737 if (not_managed) { 738 putback_lru_pages(&source); 739 goto out; 740 } 741 /* this function returns # of failed pages */ 742 ret = migrate_pages(&source, hotremove_migrate_alloc, 0, 743 true, true); 744 if (ret) 745 putback_lru_pages(&source); 746 } 747 out: 748 return ret; 749 } 750 751 /* 752 * remove from free_area[] and mark all as Reserved. 753 */ 754 static int 755 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 756 void *data) 757 { 758 __offline_isolated_pages(start, start + nr_pages); 759 return 0; 760 } 761 762 static void 763 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 764 { 765 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL, 766 offline_isolated_pages_cb); 767 } 768 769 /* 770 * Check all pages in range, recoreded as memory resource, are isolated. 771 */ 772 static int 773 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 774 void *data) 775 { 776 int ret; 777 long offlined = *(long *)data; 778 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 779 offlined = nr_pages; 780 if (!ret) 781 *(long *)data += offlined; 782 return ret; 783 } 784 785 static long 786 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 787 { 788 long offlined = 0; 789 int ret; 790 791 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined, 792 check_pages_isolated_cb); 793 if (ret < 0) 794 offlined = (long)ret; 795 return offlined; 796 } 797 798 static int offline_pages(unsigned long start_pfn, 799 unsigned long end_pfn, unsigned long timeout) 800 { 801 unsigned long pfn, nr_pages, expire; 802 long offlined_pages; 803 int ret, drain, retry_max, node; 804 struct zone *zone; 805 struct memory_notify arg; 806 807 BUG_ON(start_pfn >= end_pfn); 808 /* at least, alignment against pageblock is necessary */ 809 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 810 return -EINVAL; 811 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 812 return -EINVAL; 813 /* This makes hotplug much easier...and readable. 814 we assume this for now. .*/ 815 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 816 return -EINVAL; 817 818 lock_memory_hotplug(); 819 820 zone = page_zone(pfn_to_page(start_pfn)); 821 node = zone_to_nid(zone); 822 nr_pages = end_pfn - start_pfn; 823 824 /* set above range as isolated */ 825 ret = start_isolate_page_range(start_pfn, end_pfn); 826 if (ret) 827 goto out; 828 829 arg.start_pfn = start_pfn; 830 arg.nr_pages = nr_pages; 831 arg.status_change_nid = -1; 832 if (nr_pages >= node_present_pages(node)) 833 arg.status_change_nid = node; 834 835 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 836 ret = notifier_to_errno(ret); 837 if (ret) 838 goto failed_removal; 839 840 pfn = start_pfn; 841 expire = jiffies + timeout; 842 drain = 0; 843 retry_max = 5; 844 repeat: 845 /* start memory hot removal */ 846 ret = -EAGAIN; 847 if (time_after(jiffies, expire)) 848 goto failed_removal; 849 ret = -EINTR; 850 if (signal_pending(current)) 851 goto failed_removal; 852 ret = 0; 853 if (drain) { 854 lru_add_drain_all(); 855 cond_resched(); 856 drain_all_pages(); 857 } 858 859 pfn = scan_lru_pages(start_pfn, end_pfn); 860 if (pfn) { /* We have page on LRU */ 861 ret = do_migrate_range(pfn, end_pfn); 862 if (!ret) { 863 drain = 1; 864 goto repeat; 865 } else { 866 if (ret < 0) 867 if (--retry_max == 0) 868 goto failed_removal; 869 yield(); 870 drain = 1; 871 goto repeat; 872 } 873 } 874 /* drain all zone's lru pagevec, this is asyncronous... */ 875 lru_add_drain_all(); 876 yield(); 877 /* drain pcp pages , this is synchrouns. */ 878 drain_all_pages(); 879 /* check again */ 880 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 881 if (offlined_pages < 0) { 882 ret = -EBUSY; 883 goto failed_removal; 884 } 885 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 886 /* Ok, all of our target is islaoted. 887 We cannot do rollback at this point. */ 888 offline_isolated_pages(start_pfn, end_pfn); 889 /* reset pagetype flags and makes migrate type to be MOVABLE */ 890 undo_isolate_page_range(start_pfn, end_pfn); 891 /* removal success */ 892 zone->present_pages -= offlined_pages; 893 zone->zone_pgdat->node_present_pages -= offlined_pages; 894 totalram_pages -= offlined_pages; 895 896 setup_per_zone_wmarks(); 897 calculate_zone_inactive_ratio(zone); 898 if (!node_present_pages(node)) { 899 node_clear_state(node, N_HIGH_MEMORY); 900 kswapd_stop(node); 901 } 902 903 vm_total_pages = nr_free_pagecache_pages(); 904 writeback_set_ratelimit(); 905 906 memory_notify(MEM_OFFLINE, &arg); 907 unlock_memory_hotplug(); 908 return 0; 909 910 failed_removal: 911 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 912 start_pfn, end_pfn); 913 memory_notify(MEM_CANCEL_OFFLINE, &arg); 914 /* pushback to free area */ 915 undo_isolate_page_range(start_pfn, end_pfn); 916 917 out: 918 unlock_memory_hotplug(); 919 return ret; 920 } 921 922 int remove_memory(u64 start, u64 size) 923 { 924 unsigned long start_pfn, end_pfn; 925 926 start_pfn = PFN_DOWN(start); 927 end_pfn = start_pfn + PFN_DOWN(size); 928 return offline_pages(start_pfn, end_pfn, 120 * HZ); 929 } 930 #else 931 int remove_memory(u64 start, u64 size) 932 { 933 return -EINVAL; 934 } 935 #endif /* CONFIG_MEMORY_HOTREMOVE */ 936 EXPORT_SYMBOL_GPL(remove_memory); 937