memory_hotplug.c revision 180c06efce691f2b721dd0d965079827bdd7ee03
1/* 2 * linux/mm/memory_hotplug.c 3 * 4 * Copyright (C) 5 */ 6 7#include <linux/stddef.h> 8#include <linux/mm.h> 9#include <linux/swap.h> 10#include <linux/interrupt.h> 11#include <linux/pagemap.h> 12#include <linux/bootmem.h> 13#include <linux/compiler.h> 14#include <linux/module.h> 15#include <linux/pagevec.h> 16#include <linux/writeback.h> 17#include <linux/slab.h> 18#include <linux/sysctl.h> 19#include <linux/cpu.h> 20#include <linux/memory.h> 21#include <linux/memory_hotplug.h> 22#include <linux/highmem.h> 23#include <linux/vmalloc.h> 24#include <linux/ioport.h> 25#include <linux/cpuset.h> 26#include <linux/delay.h> 27#include <linux/migrate.h> 28#include <linux/page-isolation.h> 29 30#include <asm/tlbflush.h> 31 32/* add this memory to iomem resource */ 33static struct resource *register_memory_resource(u64 start, u64 size) 34{ 35 struct resource *res; 36 res = kzalloc(sizeof(struct resource), GFP_KERNEL); 37 BUG_ON(!res); 38 39 res->name = "System RAM"; 40 res->start = start; 41 res->end = start + size - 1; 42 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; 43 if (request_resource(&iomem_resource, res) < 0) { 44 printk("System RAM resource %llx - %llx cannot be added\n", 45 (unsigned long long)res->start, (unsigned long long)res->end); 46 kfree(res); 47 res = NULL; 48 } 49 return res; 50} 51 52static void release_memory_resource(struct resource *res) 53{ 54 if (!res) 55 return; 56 release_resource(res); 57 kfree(res); 58 return; 59} 60 61 62#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 63static int __add_zone(struct zone *zone, unsigned long phys_start_pfn) 64{ 65 struct pglist_data *pgdat = zone->zone_pgdat; 66 int nr_pages = PAGES_PER_SECTION; 67 int nid = pgdat->node_id; 68 int zone_type; 69 70 zone_type = zone - pgdat->node_zones; 71 if (!zone->wait_table) { 72 int ret = 0; 73 ret = init_currently_empty_zone(zone, phys_start_pfn, 74 nr_pages, MEMMAP_HOTPLUG); 75 if (ret < 0) 76 return ret; 77 } 78 memmap_init_zone(nr_pages, nid, zone_type, 79 phys_start_pfn, MEMMAP_HOTPLUG); 80 return 0; 81} 82 83static int __add_section(struct zone *zone, unsigned long phys_start_pfn) 84{ 85 int nr_pages = PAGES_PER_SECTION; 86 int ret; 87 88 if (pfn_valid(phys_start_pfn)) 89 return -EEXIST; 90 91 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); 92 93 if (ret < 0) 94 return ret; 95 96 ret = __add_zone(zone, phys_start_pfn); 97 98 if (ret < 0) 99 return ret; 100 101 return register_new_memory(__pfn_to_section(phys_start_pfn)); 102} 103 104static int __remove_section(struct zone *zone, struct mem_section *ms) 105{ 106 unsigned long flags; 107 struct pglist_data *pgdat = zone->zone_pgdat; 108 int ret = -EINVAL; 109 110 if (!valid_section(ms)) 111 return ret; 112 113 ret = unregister_memory_section(ms); 114 if (ret) 115 return ret; 116 117 pgdat_resize_lock(pgdat, &flags); 118 sparse_remove_one_section(zone, ms); 119 pgdat_resize_unlock(pgdat, &flags); 120 return 0; 121} 122 123/* 124 * Reasonably generic function for adding memory. It is 125 * expected that archs that support memory hotplug will 126 * call this function after deciding the zone to which to 127 * add the new pages. 128 */ 129int __add_pages(struct zone *zone, unsigned long phys_start_pfn, 130 unsigned long nr_pages) 131{ 132 unsigned long i; 133 int err = 0; 134 int start_sec, end_sec; 135 /* during initialize mem_map, align hot-added range to section */ 136 start_sec = pfn_to_section_nr(phys_start_pfn); 137 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); 138 139 for (i = start_sec; i <= end_sec; i++) { 140 err = __add_section(zone, i << PFN_SECTION_SHIFT); 141 142 /* 143 * EEXIST is finally dealt with by ioresource collision 144 * check. see add_memory() => register_memory_resource() 145 * Warning will be printed if there is collision. 146 */ 147 if (err && (err != -EEXIST)) 148 break; 149 err = 0; 150 } 151 152 return err; 153} 154EXPORT_SYMBOL_GPL(__add_pages); 155 156/** 157 * __remove_pages() - remove sections of pages from a zone 158 * @zone: zone from which pages need to be removed 159 * @phys_start_pfn: starting pageframe (must be aligned to start of a section) 160 * @nr_pages: number of pages to remove (must be multiple of section size) 161 * 162 * Generic helper function to remove section mappings and sysfs entries 163 * for the section of the memory we are removing. Caller needs to make 164 * sure that pages are marked reserved and zones are adjust properly by 165 * calling offline_pages(). 166 */ 167int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, 168 unsigned long nr_pages) 169{ 170 unsigned long i, ret = 0; 171 int sections_to_remove; 172 173 /* 174 * We can only remove entire sections 175 */ 176 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); 177 BUG_ON(nr_pages % PAGES_PER_SECTION); 178 179 release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE); 180 181 sections_to_remove = nr_pages / PAGES_PER_SECTION; 182 for (i = 0; i < sections_to_remove; i++) { 183 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; 184 ret = __remove_section(zone, __pfn_to_section(pfn)); 185 if (ret) 186 break; 187 } 188 return ret; 189} 190EXPORT_SYMBOL_GPL(__remove_pages); 191 192static void grow_zone_span(struct zone *zone, 193 unsigned long start_pfn, unsigned long end_pfn) 194{ 195 unsigned long old_zone_end_pfn; 196 197 zone_span_writelock(zone); 198 199 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; 200 if (start_pfn < zone->zone_start_pfn) 201 zone->zone_start_pfn = start_pfn; 202 203 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - 204 zone->zone_start_pfn; 205 206 zone_span_writeunlock(zone); 207} 208 209static void grow_pgdat_span(struct pglist_data *pgdat, 210 unsigned long start_pfn, unsigned long end_pfn) 211{ 212 unsigned long old_pgdat_end_pfn = 213 pgdat->node_start_pfn + pgdat->node_spanned_pages; 214 215 if (start_pfn < pgdat->node_start_pfn) 216 pgdat->node_start_pfn = start_pfn; 217 218 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - 219 pgdat->node_start_pfn; 220} 221 222void online_page(struct page *page) 223{ 224 totalram_pages++; 225 num_physpages++; 226 227#ifdef CONFIG_HIGHMEM 228 if (PageHighMem(page)) 229 totalhigh_pages++; 230#endif 231 232#ifdef CONFIG_FLATMEM 233 max_mapnr = max(page_to_pfn(page), max_mapnr); 234#endif 235 236 ClearPageReserved(page); 237 init_page_count(page); 238 __free_page(page); 239} 240 241static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, 242 void *arg) 243{ 244 unsigned long i; 245 unsigned long onlined_pages = *(unsigned long *)arg; 246 struct page *page; 247 if (PageReserved(pfn_to_page(start_pfn))) 248 for (i = 0; i < nr_pages; i++) { 249 page = pfn_to_page(start_pfn + i); 250 online_page(page); 251 onlined_pages++; 252 } 253 *(unsigned long *)arg = onlined_pages; 254 return 0; 255} 256 257 258int online_pages(unsigned long pfn, unsigned long nr_pages) 259{ 260 unsigned long flags; 261 unsigned long onlined_pages = 0; 262 struct zone *zone; 263 int need_zonelists_rebuild = 0; 264 int nid; 265 int ret; 266 struct memory_notify arg; 267 268 arg.start_pfn = pfn; 269 arg.nr_pages = nr_pages; 270 arg.status_change_nid = -1; 271 272 nid = page_to_nid(pfn_to_page(pfn)); 273 if (node_present_pages(nid) == 0) 274 arg.status_change_nid = nid; 275 276 ret = memory_notify(MEM_GOING_ONLINE, &arg); 277 ret = notifier_to_errno(ret); 278 if (ret) { 279 memory_notify(MEM_CANCEL_ONLINE, &arg); 280 return ret; 281 } 282 /* 283 * This doesn't need a lock to do pfn_to_page(). 284 * The section can't be removed here because of the 285 * memory_block->state_mutex. 286 */ 287 zone = page_zone(pfn_to_page(pfn)); 288 pgdat_resize_lock(zone->zone_pgdat, &flags); 289 grow_zone_span(zone, pfn, pfn + nr_pages); 290 grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages); 291 pgdat_resize_unlock(zone->zone_pgdat, &flags); 292 293 /* 294 * If this zone is not populated, then it is not in zonelist. 295 * This means the page allocator ignores this zone. 296 * So, zonelist must be updated after online. 297 */ 298 if (!populated_zone(zone)) 299 need_zonelists_rebuild = 1; 300 301 walk_memory_resource(pfn, nr_pages, &onlined_pages, 302 online_pages_range); 303 zone->present_pages += onlined_pages; 304 zone->zone_pgdat->node_present_pages += onlined_pages; 305 306 setup_per_zone_pages_min(); 307 if (onlined_pages) { 308 kswapd_run(zone_to_nid(zone)); 309 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); 310 } 311 312 if (need_zonelists_rebuild) 313 build_all_zonelists(); 314 vm_total_pages = nr_free_pagecache_pages(); 315 writeback_set_ratelimit(); 316 317 if (onlined_pages) 318 memory_notify(MEM_ONLINE, &arg); 319 320 return 0; 321} 322#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 323 324static pg_data_t *hotadd_new_pgdat(int nid, u64 start) 325{ 326 struct pglist_data *pgdat; 327 unsigned long zones_size[MAX_NR_ZONES] = {0}; 328 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 329 unsigned long start_pfn = start >> PAGE_SHIFT; 330 331 pgdat = arch_alloc_nodedata(nid); 332 if (!pgdat) 333 return NULL; 334 335 arch_refresh_nodedata(nid, pgdat); 336 337 /* we can use NODE_DATA(nid) from here */ 338 339 /* init node's zones as empty zones, we don't have any present pages.*/ 340 free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size); 341 342 return pgdat; 343} 344 345static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 346{ 347 arch_refresh_nodedata(nid, NULL); 348 arch_free_nodedata(pgdat); 349 return; 350} 351 352 353int add_memory(int nid, u64 start, u64 size) 354{ 355 pg_data_t *pgdat = NULL; 356 int new_pgdat = 0; 357 struct resource *res; 358 int ret; 359 360 res = register_memory_resource(start, size); 361 if (!res) 362 return -EEXIST; 363 364 if (!node_online(nid)) { 365 pgdat = hotadd_new_pgdat(nid, start); 366 if (!pgdat) 367 return -ENOMEM; 368 new_pgdat = 1; 369 } 370 371 /* call arch's memory hotadd */ 372 ret = arch_add_memory(nid, start, size); 373 374 if (ret < 0) 375 goto error; 376 377 /* we online node here. we can't roll back from here. */ 378 node_set_online(nid); 379 380 cpuset_track_online_nodes(); 381 382 if (new_pgdat) { 383 ret = register_one_node(nid); 384 /* 385 * If sysfs file of new node can't create, cpu on the node 386 * can't be hot-added. There is no rollback way now. 387 * So, check by BUG_ON() to catch it reluctantly.. 388 */ 389 BUG_ON(ret); 390 } 391 392 return ret; 393error: 394 /* rollback pgdat allocation and others */ 395 if (new_pgdat) 396 rollback_node_hotadd(nid, pgdat); 397 if (res) 398 release_memory_resource(res); 399 400 return ret; 401} 402EXPORT_SYMBOL_GPL(add_memory); 403 404#ifdef CONFIG_MEMORY_HOTREMOVE 405/* 406 * Confirm all pages in a range [start, end) is belongs to the same zone. 407 */ 408static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 409{ 410 unsigned long pfn; 411 struct zone *zone = NULL; 412 struct page *page; 413 int i; 414 for (pfn = start_pfn; 415 pfn < end_pfn; 416 pfn += MAX_ORDER_NR_PAGES) { 417 i = 0; 418 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 419 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) 420 i++; 421 if (i == MAX_ORDER_NR_PAGES) 422 continue; 423 page = pfn_to_page(pfn + i); 424 if (zone && page_zone(page) != zone) 425 return 0; 426 zone = page_zone(page); 427 } 428 return 1; 429} 430 431/* 432 * Scanning pfn is much easier than scanning lru list. 433 * Scan pfn from start to end and Find LRU page. 434 */ 435int scan_lru_pages(unsigned long start, unsigned long end) 436{ 437 unsigned long pfn; 438 struct page *page; 439 for (pfn = start; pfn < end; pfn++) { 440 if (pfn_valid(pfn)) { 441 page = pfn_to_page(pfn); 442 if (PageLRU(page)) 443 return pfn; 444 } 445 } 446 return 0; 447} 448 449static struct page * 450hotremove_migrate_alloc(struct page *page, 451 unsigned long private, 452 int **x) 453{ 454 /* This should be improoooooved!! */ 455 return alloc_page(GFP_HIGHUSER_PAGECACHE); 456} 457 458 459#define NR_OFFLINE_AT_ONCE_PAGES (256) 460static int 461do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 462{ 463 unsigned long pfn; 464 struct page *page; 465 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 466 int not_managed = 0; 467 int ret = 0; 468 LIST_HEAD(source); 469 470 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 471 if (!pfn_valid(pfn)) 472 continue; 473 page = pfn_to_page(pfn); 474 if (!page_count(page)) 475 continue; 476 /* 477 * We can skip free pages. And we can only deal with pages on 478 * LRU. 479 */ 480 ret = isolate_lru_page(page, &source); 481 if (!ret) { /* Success */ 482 move_pages--; 483 } else { 484 /* Becasue we don't have big zone->lock. we should 485 check this again here. */ 486 if (page_count(page)) 487 not_managed++; 488#ifdef CONFIG_DEBUG_VM 489 printk(KERN_INFO "removing from LRU failed" 490 " %lx/%d/%lx\n", 491 pfn, page_count(page), page->flags); 492#endif 493 } 494 } 495 ret = -EBUSY; 496 if (not_managed) { 497 if (!list_empty(&source)) 498 putback_lru_pages(&source); 499 goto out; 500 } 501 ret = 0; 502 if (list_empty(&source)) 503 goto out; 504 /* this function returns # of failed pages */ 505 ret = migrate_pages(&source, hotremove_migrate_alloc, 0); 506 507out: 508 return ret; 509} 510 511/* 512 * remove from free_area[] and mark all as Reserved. 513 */ 514static int 515offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 516 void *data) 517{ 518 __offline_isolated_pages(start, start + nr_pages); 519 return 0; 520} 521 522static void 523offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 524{ 525 walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL, 526 offline_isolated_pages_cb); 527} 528 529/* 530 * Check all pages in range, recoreded as memory resource, are isolated. 531 */ 532static int 533check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 534 void *data) 535{ 536 int ret; 537 long offlined = *(long *)data; 538 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); 539 offlined = nr_pages; 540 if (!ret) 541 *(long *)data += offlined; 542 return ret; 543} 544 545static long 546check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 547{ 548 long offlined = 0; 549 int ret; 550 551 ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined, 552 check_pages_isolated_cb); 553 if (ret < 0) 554 offlined = (long)ret; 555 return offlined; 556} 557 558int offline_pages(unsigned long start_pfn, 559 unsigned long end_pfn, unsigned long timeout) 560{ 561 unsigned long pfn, nr_pages, expire; 562 long offlined_pages; 563 int ret, drain, retry_max, node; 564 struct zone *zone; 565 struct memory_notify arg; 566 567 BUG_ON(start_pfn >= end_pfn); 568 /* at least, alignment against pageblock is necessary */ 569 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 570 return -EINVAL; 571 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 572 return -EINVAL; 573 /* This makes hotplug much easier...and readable. 574 we assume this for now. .*/ 575 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 576 return -EINVAL; 577 578 zone = page_zone(pfn_to_page(start_pfn)); 579 node = zone_to_nid(zone); 580 nr_pages = end_pfn - start_pfn; 581 582 /* set above range as isolated */ 583 ret = start_isolate_page_range(start_pfn, end_pfn); 584 if (ret) 585 return ret; 586 587 arg.start_pfn = start_pfn; 588 arg.nr_pages = nr_pages; 589 arg.status_change_nid = -1; 590 if (nr_pages >= node_present_pages(node)) 591 arg.status_change_nid = node; 592 593 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 594 ret = notifier_to_errno(ret); 595 if (ret) 596 goto failed_removal; 597 598 pfn = start_pfn; 599 expire = jiffies + timeout; 600 drain = 0; 601 retry_max = 5; 602repeat: 603 /* start memory hot removal */ 604 ret = -EAGAIN; 605 if (time_after(jiffies, expire)) 606 goto failed_removal; 607 ret = -EINTR; 608 if (signal_pending(current)) 609 goto failed_removal; 610 ret = 0; 611 if (drain) { 612 lru_add_drain_all(); 613 flush_scheduled_work(); 614 cond_resched(); 615 drain_all_pages(); 616 } 617 618 pfn = scan_lru_pages(start_pfn, end_pfn); 619 if (pfn) { /* We have page on LRU */ 620 ret = do_migrate_range(pfn, end_pfn); 621 if (!ret) { 622 drain = 1; 623 goto repeat; 624 } else { 625 if (ret < 0) 626 if (--retry_max == 0) 627 goto failed_removal; 628 yield(); 629 drain = 1; 630 goto repeat; 631 } 632 } 633 /* drain all zone's lru pagevec, this is asyncronous... */ 634 lru_add_drain_all(); 635 flush_scheduled_work(); 636 yield(); 637 /* drain pcp pages , this is synchrouns. */ 638 drain_all_pages(); 639 /* check again */ 640 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 641 if (offlined_pages < 0) { 642 ret = -EBUSY; 643 goto failed_removal; 644 } 645 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 646 /* Ok, all of our target is islaoted. 647 We cannot do rollback at this point. */ 648 offline_isolated_pages(start_pfn, end_pfn); 649 /* reset pagetype flags and makes migrate type to be MOVABLE */ 650 undo_isolate_page_range(start_pfn, end_pfn); 651 /* removal success */ 652 zone->present_pages -= offlined_pages; 653 zone->zone_pgdat->node_present_pages -= offlined_pages; 654 totalram_pages -= offlined_pages; 655 num_physpages -= offlined_pages; 656 657 vm_total_pages = nr_free_pagecache_pages(); 658 writeback_set_ratelimit(); 659 660 memory_notify(MEM_OFFLINE, &arg); 661 return 0; 662 663failed_removal: 664 printk(KERN_INFO "memory offlining %lx to %lx failed\n", 665 start_pfn, end_pfn); 666 memory_notify(MEM_CANCEL_OFFLINE, &arg); 667 /* pushback to free area */ 668 undo_isolate_page_range(start_pfn, end_pfn); 669 670 return ret; 671} 672#else 673int remove_memory(u64 start, u64 size) 674{ 675 return -EINVAL; 676} 677EXPORT_SYMBOL_GPL(remove_memory); 678#endif /* CONFIG_MEMORY_HOTREMOVE */ 679