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 ClearPageReserved(page); 378 init_page_count(page); 379 __free_page(page); 380 } 381 382 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, 383 void *arg) 384 { 385 unsigned long i; 386 unsigned long onlined_pages = *(unsigned long *)arg; 387 struct page *page; 388 if (PageReserved(pfn_to_page(start_pfn))) 389 for (i = 0; i < nr_pages; i++) { 390 page = pfn_to_page(start_pfn + i); 391 online_page(page); 392 onlined_pages++; 393 } 394 *(unsigned long *)arg = onlined_pages; 395 return 0; 396 } 397 398 399 int __ref online_pages(unsigned long pfn, unsigned long nr_pages) 400 { 401 unsigned long onlined_pages = 0; 402 struct zone *zone; 403 int need_zonelists_rebuild = 0; 404 int nid; 405 int ret; 406 struct memory_notify arg; 407 408 lock_memory_hotplug(); 409 arg.start_pfn = pfn; 410 arg.nr_pages = nr_pages; 411 arg.status_change_nid = -1; 412 413 nid = page_to_nid(pfn_to_page(pfn)); 414 if (node_present_pages(nid) == 0) 415 arg.status_change_nid = nid; 416 417 ret = memory_notify(MEM_GOING_ONLINE, &arg); 418 ret = notifier_to_errno(ret); 419 if (ret) { 420 memory_notify(MEM_CANCEL_ONLINE, &arg); 421 unlock_memory_hotplug(); 422 return ret; 423 } 424 /* 425 * This doesn't need a lock to do pfn_to_page(). 426 * The section can't be removed here because of the 427 * memory_block->state_mutex. 428 */ 429 zone = page_zone(pfn_to_page(pfn)); 430 /* 431 * If this zone is not populated, then it is not in zonelist. 432 * This means the page allocator ignores this zone. 433 * So, zonelist must be updated after online. 434 */ 435 mutex_lock(&zonelists_mutex); 436 if (!populated_zone(zone)) 437 need_zonelists_rebuild = 1; 438 439 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages, 440 online_pages_range); 441 if (ret) { 442 mutex_unlock(&zonelists_mutex); 443 printk(KERN_DEBUG "online_pages %lx at %lx failed\n", 444 nr_pages, pfn); 445 memory_notify(MEM_CANCEL_ONLINE, &arg); 446 unlock_memory_hotplug(); 447 return ret; 448 } 449 450 zone->present_pages += onlined_pages; 451 zone->zone_pgdat->node_present_pages += onlined_pages; 452 if (need_zonelists_rebuild) 453 build_all_zonelists(zone); 454 else 455 zone_pcp_update(zone); 456 457 mutex_unlock(&zonelists_mutex); 458 459 init_per_zone_wmark_min(); 460 461 if (onlined_pages) { 462 kswapd_run(zone_to_nid(zone)); 463 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); 464 } 465 466 vm_total_pages = nr_free_pagecache_pages(); 467 468 writeback_set_ratelimit(); 469 470 if (onlined_pages) 471 memory_notify(MEM_ONLINE, &arg); 472 unlock_memory_hotplug(); 473 474 return 0; 475 } 476 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 477 478 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 479 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) 480 { 481 struct pglist_data *pgdat; 482 unsigned long zones_size[MAX_NR_ZONES] = {0}; 483 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 484 unsigned long start_pfn = start >> PAGE_SHIFT; 485 486 pgdat = arch_alloc_nodedata(nid); 487 if (!pgdat) 488 return NULL; 489 490 arch_refresh_nodedata(nid, pgdat); 491 492 /* we can use NODE_DATA(nid) from here */ 493 494 /* init node's zones as empty zones, we don't have any present pages.*/ 495 free_area_init_node(nid, zones_size, start_pfn, zholes_size); 496 497 /* 498 * The node we allocated has no zone fallback lists. For avoiding 499 * to access not-initialized zonelist, build here. 500 */ 501 mutex_lock(&zonelists_mutex); 502 build_all_zonelists(NULL); 503 mutex_unlock(&zonelists_mutex); 504 505 return pgdat; 506 } 507 508 static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 509 { 510 arch_refresh_nodedata(nid, NULL); 511 arch_free_nodedata(pgdat); 512 return; 513 } 514 515 516 /* 517 * called by cpu_up() to online a node without onlined memory. 518 */ 519 int mem_online_node(int nid) 520 { 521 pg_data_t *pgdat; 522 int ret; 523 524 lock_memory_hotplug(); 525 pgdat = hotadd_new_pgdat(nid, 0); 526 if (!pgdat) { 527 ret = -ENOMEM; 528 goto out; 529 } 530 node_set_online(nid); 531 ret = register_one_node(nid); 532 BUG_ON(ret); 533 534 out: 535 unlock_memory_hotplug(); 536 return ret; 537 } 538 539 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 540 int __ref add_memory(int nid, u64 start, u64 size) 541 { 542 pg_data_t *pgdat = NULL; 543 int new_pgdat = 0; 544 struct resource *res; 545 int ret; 546 547 lock_memory_hotplug(); 548 549 res = register_memory_resource(start, size); 550 ret = -EEXIST; 551 if (!res) 552 goto out; 553 554 if (!node_online(nid)) { 555 pgdat = hotadd_new_pgdat(nid, start); 556 ret = -ENOMEM; 557 if (!pgdat) 558 goto out; 559 new_pgdat = 1; 560 } 561 562 /* call arch's memory hotadd */ 563 ret = arch_add_memory(nid, start, size); 564 565 if (ret < 0) 566 goto error; 567 568 /* we online node here. we can't roll back from here. */ 569 node_set_online(nid); 570 571 if (new_pgdat) { 572 ret = register_one_node(nid); 573 /* 574 * If sysfs file of new node can't create, cpu on the node 575 * can't be hot-added. There is no rollback way now. 576 * So, check by BUG_ON() to catch it reluctantly.. 577 */ 578 BUG_ON(ret); 579 } 580 581 /* create new memmap entry */ 582 firmware_map_add_hotplug(start, start + size, "System RAM"); 583 584 goto out; 585 586 error: 587 /* rollback pgdat allocation and others */ 588 if (new_pgdat) 589 rollback_node_hotadd(nid, pgdat); 590 if (res) 591 release_memory_resource(res); 592 593 out: 594 unlock_memory_hotplug(); 595 return ret; 596 } 597 EXPORT_SYMBOL_GPL(add_memory); 598 599 #ifdef CONFIG_MEMORY_HOTREMOVE 600 /* 601 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy 602 * set and the size of the free page is given by page_order(). Using this, 603 * the function determines if the pageblock contains only free pages. 604 * Due to buddy contraints, a free page at least the size of a pageblock will 605 * be located at the start of the pageblock 606 */ 607 static inline int pageblock_free(struct page *page) 608 { 609 return PageBuddy(page) && page_order(page) >= pageblock_order; 610 } 611 612 /* Return the start of the next active pageblock after a given page */ 613 static struct page *next_active_pageblock(struct page *page) 614 { 615 /* Ensure the starting page is pageblock-aligned */ 616 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1)); 617 618 /* If the entire pageblock is free, move to the end of free page */ 619 if (pageblock_free(page)) { 620 int order; 621 /* be careful. we don't have locks, page_order can be changed.*/ 622 order = page_order(page); 623 if ((order < MAX_ORDER) && (order >= pageblock_order)) 624 return page + (1 << order); 625 } 626 627 return page + pageblock_nr_pages; 628 } 629 630 /* Checks if this range of memory is likely to be hot-removable. */ 631 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) 632 { 633 struct page *page = pfn_to_page(start_pfn); 634 struct page *end_page = page + nr_pages; 635 636 /* Check the starting page of each pageblock within the range */ 637 for (; page < end_page; page = next_active_pageblock(page)) { 638 if (!is_pageblock_removable_nolock(page)) 639 return 0; 640 cond_resched(); 641 } 642 643 /* All pageblocks in the memory block are likely to be hot-removable */ 644 return 1; 645 } 646 647 /* 648 * Confirm all pages in a range [start, end) is belongs to the same zone. 649 */ 650 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 651 { 652 unsigned long pfn; 653 struct zone *zone = NULL; 654 struct page *page; 655 int i; 656 for (pfn = start_pfn; 657 pfn < end_pfn; 658 pfn += MAX_ORDER_NR_PAGES) { 659 i = 0; 660 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 661 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 662 i++; 663 if (i == MAX_ORDER_NR_PAGES) 664 continue; 665 page = pfn_to_page(pfn + i); 666 if (zone && page_zone(page) != zone) 667 return 0; 668 zone = page_zone(page); 669 } 670 return 1; 671 } 672 673 /* 674 * Scanning pfn is much easier than scanning lru list. 675 * Scan pfn from start to end and Find LRU page. 676 */ 677 static unsigned long scan_lru_pages(unsigned long start, unsigned long end) 678 { 679 unsigned long pfn; 680 struct page *page; 681 for (pfn = start; pfn < end; pfn++) { 682 if (pfn_valid(pfn)) { 683 page = pfn_to_page(pfn); 684 if (PageLRU(page)) 685 return pfn; 686 } 687 } 688 return 0; 689 } 690 691 static struct page * 692 hotremove_migrate_alloc(struct page *page, unsigned long private, int **x) 693 { 694 /* This should be improooooved!! */ 695 return alloc_page(GFP_HIGHUSER_MOVABLE); 696 } 697 698 #define NR_OFFLINE_AT_ONCE_PAGES (256) 699 static int 700 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 701 { 702 unsigned long pfn; 703 struct page *page; 704 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 705 int not_managed = 0; 706 int ret = 0; 707 LIST_HEAD(source); 708 709 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 710 if (!pfn_valid(pfn)) 711 continue; 712 page = pfn_to_page(pfn); 713 if (!get_page_unless_zero(page)) 714 continue; 715 /* 716 * We can skip free pages. And we can only deal with pages on 717 * LRU. 718 */ 719 ret = isolate_lru_page(page); 720 if (!ret) { /* Success */ 721 put_page(page); 722 list_add_tail(&page->lru, &source); 723 move_pages--; 724 inc_zone_page_state(page, NR_ISOLATED_ANON + 725 page_is_file_cache(page)); 726 727 } else { 728 #ifdef CONFIG_DEBUG_VM 729 printk(KERN_ALERT "removing pfn %lx from LRU failed\n", 730 pfn); 731 dump_page(page); 732 #endif 733 put_page(page); 734 /* Because we don't have big zone->lock. we should 735 check this again here. */ 736 if (page_count(page)) { 737 not_managed++; 738 ret = -EBUSY; 739 break; 740 } 741 } 742 } 743 if (!list_empty(&source)) { 744 if (not_managed) { 745 putback_lru_pages(&source); 746 goto out; 747 } 748 /* this function returns # of failed pages */ 749 ret = migrate_pages(&source, hotremove_migrate_alloc, 0, 750 true, true); 751 if (ret) 752 putback_lru_pages(&source); 753 } 754 out: 755 return ret; 756 } 757 758 /* 759 * remove from free_area[] and mark all as Reserved. 760 */ 761 static int 762 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 763 void *data) 764 { 765 __offline_isolated_pages(start, start + nr_pages); 766 return 0; 767 } 768 769 static void 770 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 771 { 772 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL, 773 offline_isolated_pages_cb); 774 } 775 776 /* 777 * Check all pages in range, recoreded as memory resource, are isolated. 778 */ 779 static int 780 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 781 void *data) 782 { 783 int ret; 784 long offlined = *(long *)data; 785 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 786 offlined = nr_pages; 787 if (!ret) 788 *(long *)data += offlined; 789 return ret; 790 } 791 792 static long 793 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 794 { 795 long offlined = 0; 796 int ret; 797 798 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined, 799 check_pages_isolated_cb); 800 if (ret < 0) 801 offlined = (long)ret; 802 return offlined; 803 } 804 805 static int __ref offline_pages(unsigned long start_pfn, 806 unsigned long end_pfn, unsigned long timeout) 807 { 808 unsigned long pfn, nr_pages, expire; 809 long offlined_pages; 810 int ret, drain, retry_max, node; 811 struct zone *zone; 812 struct memory_notify arg; 813 814 BUG_ON(start_pfn >= end_pfn); 815 /* at least, alignment against pageblock is necessary */ 816 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 817 return -EINVAL; 818 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 819 return -EINVAL; 820 /* This makes hotplug much easier...and readable. 821 we assume this for now. .*/ 822 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 823 return -EINVAL; 824 825 lock_memory_hotplug(); 826 827 zone = page_zone(pfn_to_page(start_pfn)); 828 node = zone_to_nid(zone); 829 nr_pages = end_pfn - start_pfn; 830 831 /* set above range as isolated */ 832 ret = start_isolate_page_range(start_pfn, end_pfn); 833 if (ret) 834 goto out; 835 836 arg.start_pfn = start_pfn; 837 arg.nr_pages = nr_pages; 838 arg.status_change_nid = -1; 839 if (nr_pages >= node_present_pages(node)) 840 arg.status_change_nid = node; 841 842 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 843 ret = notifier_to_errno(ret); 844 if (ret) 845 goto failed_removal; 846 847 pfn = start_pfn; 848 expire = jiffies + timeout; 849 drain = 0; 850 retry_max = 5; 851 repeat: 852 /* start memory hot removal */ 853 ret = -EAGAIN; 854 if (time_after(jiffies, expire)) 855 goto failed_removal; 856 ret = -EINTR; 857 if (signal_pending(current)) 858 goto failed_removal; 859 ret = 0; 860 if (drain) { 861 lru_add_drain_all(); 862 cond_resched(); 863 drain_all_pages(); 864 } 865 866 pfn = scan_lru_pages(start_pfn, end_pfn); 867 if (pfn) { /* We have page on LRU */ 868 ret = do_migrate_range(pfn, end_pfn); 869 if (!ret) { 870 drain = 1; 871 goto repeat; 872 } else { 873 if (ret < 0) 874 if (--retry_max == 0) 875 goto failed_removal; 876 yield(); 877 drain = 1; 878 goto repeat; 879 } 880 } 881 /* drain all zone's lru pagevec, this is asyncronous... */ 882 lru_add_drain_all(); 883 yield(); 884 /* drain pcp pages , this is synchrouns. */ 885 drain_all_pages(); 886 /* check again */ 887 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 888 if (offlined_pages < 0) { 889 ret = -EBUSY; 890 goto failed_removal; 891 } 892 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 893 /* Ok, all of our target is islaoted. 894 We cannot do rollback at this point. */ 895 offline_isolated_pages(start_pfn, end_pfn); 896 /* reset pagetype flags and makes migrate type to be MOVABLE */ 897 undo_isolate_page_range(start_pfn, end_pfn); 898 /* removal success */ 899 zone->present_pages -= offlined_pages; 900 zone->zone_pgdat->node_present_pages -= offlined_pages; 901 totalram_pages -= offlined_pages; 902 903 init_per_zone_wmark_min(); 904 905 if (!node_present_pages(node)) { 906 node_clear_state(node, N_HIGH_MEMORY); 907 kswapd_stop(node); 908 } 909 910 vm_total_pages = nr_free_pagecache_pages(); 911 writeback_set_ratelimit(); 912 913 memory_notify(MEM_OFFLINE, &arg); 914 unlock_memory_hotplug(); 915 return 0; 916 917 failed_removal: 918 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 919 start_pfn, end_pfn); 920 memory_notify(MEM_CANCEL_OFFLINE, &arg); 921 /* pushback to free area */ 922 undo_isolate_page_range(start_pfn, end_pfn); 923 924 out: 925 unlock_memory_hotplug(); 926 return ret; 927 } 928 929 int remove_memory(u64 start, u64 size) 930 { 931 unsigned long start_pfn, end_pfn; 932 933 start_pfn = PFN_DOWN(start); 934 end_pfn = start_pfn + PFN_DOWN(size); 935 return offline_pages(start_pfn, end_pfn, 120 * HZ); 936 } 937 #else 938 int remove_memory(u64 start, u64 size) 939 { 940 return -EINVAL; 941 } 942 #endif /* CONFIG_MEMORY_HOTREMOVE */ 943 EXPORT_SYMBOL_GPL(remove_memory); 944