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/compiler.h> 13 #include <linux/export.h> 14 #include <linux/pagevec.h> 15 #include <linux/writeback.h> 16 #include <linux/slab.h> 17 #include <linux/sysctl.h> 18 #include <linux/cpu.h> 19 #include <linux/memory.h> 20 #include <linux/memremap.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 #include <linux/stop_machine.h> 33 #include <linux/hugetlb.h> 34 #include <linux/memblock.h> 35 #include <linux/bootmem.h> 36 37 #include <asm/tlbflush.h> 38 39 #include "internal.h" 40 41 /* 42 * online_page_callback contains pointer to current page onlining function. 43 * Initially it is generic_online_page(). If it is required it could be 44 * changed by calling set_online_page_callback() for callback registration 45 * and restore_online_page_callback() for generic callback restore. 46 */ 47 48 static void generic_online_page(struct page *page); 49 50 static online_page_callback_t online_page_callback = generic_online_page; 51 static DEFINE_MUTEX(online_page_callback_lock); 52 53 /* The same as the cpu_hotplug lock, but for memory hotplug. */ 54 static struct { 55 struct task_struct *active_writer; 56 struct mutex lock; /* Synchronizes accesses to refcount, */ 57 /* 58 * Also blocks the new readers during 59 * an ongoing mem hotplug operation. 60 */ 61 int refcount; 62 63 #ifdef CONFIG_DEBUG_LOCK_ALLOC 64 struct lockdep_map dep_map; 65 #endif 66 } mem_hotplug = { 67 .active_writer = NULL, 68 .lock = __MUTEX_INITIALIZER(mem_hotplug.lock), 69 .refcount = 0, 70 #ifdef CONFIG_DEBUG_LOCK_ALLOC 71 .dep_map = {.name = "mem_hotplug.lock" }, 72 #endif 73 }; 74 75 /* Lockdep annotations for get/put_online_mems() and mem_hotplug_begin/end() */ 76 #define memhp_lock_acquire_read() lock_map_acquire_read(&mem_hotplug.dep_map) 77 #define memhp_lock_acquire() lock_map_acquire(&mem_hotplug.dep_map) 78 #define memhp_lock_release() lock_map_release(&mem_hotplug.dep_map) 79 80 void get_online_mems(void) 81 { 82 might_sleep(); 83 if (mem_hotplug.active_writer == current) 84 return; 85 memhp_lock_acquire_read(); 86 mutex_lock(&mem_hotplug.lock); 87 mem_hotplug.refcount++; 88 mutex_unlock(&mem_hotplug.lock); 89 90 } 91 92 void put_online_mems(void) 93 { 94 if (mem_hotplug.active_writer == current) 95 return; 96 mutex_lock(&mem_hotplug.lock); 97 98 if (WARN_ON(!mem_hotplug.refcount)) 99 mem_hotplug.refcount++; /* try to fix things up */ 100 101 if (!--mem_hotplug.refcount && unlikely(mem_hotplug.active_writer)) 102 wake_up_process(mem_hotplug.active_writer); 103 mutex_unlock(&mem_hotplug.lock); 104 memhp_lock_release(); 105 106 } 107 108 void mem_hotplug_begin(void) 109 { 110 mem_hotplug.active_writer = current; 111 112 memhp_lock_acquire(); 113 for (;;) { 114 mutex_lock(&mem_hotplug.lock); 115 if (likely(!mem_hotplug.refcount)) 116 break; 117 __set_current_state(TASK_UNINTERRUPTIBLE); 118 mutex_unlock(&mem_hotplug.lock); 119 schedule(); 120 } 121 } 122 123 void mem_hotplug_done(void) 124 { 125 mem_hotplug.active_writer = NULL; 126 mutex_unlock(&mem_hotplug.lock); 127 memhp_lock_release(); 128 } 129 130 /* add this memory to iomem resource */ 131 static struct resource *register_memory_resource(u64 start, u64 size) 132 { 133 struct resource *res; 134 res = kzalloc(sizeof(struct resource), GFP_KERNEL); 135 if (!res) 136 return ERR_PTR(-ENOMEM); 137 138 res->name = "System RAM"; 139 res->start = start; 140 res->end = start + size - 1; 141 res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; 142 if (request_resource(&iomem_resource, res) < 0) { 143 pr_debug("System RAM resource %pR cannot be added\n", res); 144 kfree(res); 145 return ERR_PTR(-EEXIST); 146 } 147 return res; 148 } 149 150 static void release_memory_resource(struct resource *res) 151 { 152 if (!res) 153 return; 154 release_resource(res); 155 kfree(res); 156 return; 157 } 158 159 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 160 void get_page_bootmem(unsigned long info, struct page *page, 161 unsigned long type) 162 { 163 page->lru.next = (struct list_head *) type; 164 SetPagePrivate(page); 165 set_page_private(page, info); 166 atomic_inc(&page->_count); 167 } 168 169 void put_page_bootmem(struct page *page) 170 { 171 unsigned long type; 172 173 type = (unsigned long) page->lru.next; 174 BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || 175 type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE); 176 177 if (atomic_dec_return(&page->_count) == 1) { 178 ClearPagePrivate(page); 179 set_page_private(page, 0); 180 INIT_LIST_HEAD(&page->lru); 181 free_reserved_page(page); 182 } 183 } 184 185 #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE 186 #ifndef CONFIG_SPARSEMEM_VMEMMAP 187 static void register_page_bootmem_info_section(unsigned long start_pfn) 188 { 189 unsigned long *usemap, mapsize, section_nr, i; 190 struct mem_section *ms; 191 struct page *page, *memmap; 192 193 section_nr = pfn_to_section_nr(start_pfn); 194 ms = __nr_to_section(section_nr); 195 196 /* Get section's memmap address */ 197 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); 198 199 /* 200 * Get page for the memmap's phys address 201 * XXX: need more consideration for sparse_vmemmap... 202 */ 203 page = virt_to_page(memmap); 204 mapsize = sizeof(struct page) * PAGES_PER_SECTION; 205 mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT; 206 207 /* remember memmap's page */ 208 for (i = 0; i < mapsize; i++, page++) 209 get_page_bootmem(section_nr, page, SECTION_INFO); 210 211 usemap = __nr_to_section(section_nr)->pageblock_flags; 212 page = virt_to_page(usemap); 213 214 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; 215 216 for (i = 0; i < mapsize; i++, page++) 217 get_page_bootmem(section_nr, page, MIX_SECTION_INFO); 218 219 } 220 #else /* CONFIG_SPARSEMEM_VMEMMAP */ 221 static void register_page_bootmem_info_section(unsigned long start_pfn) 222 { 223 unsigned long *usemap, mapsize, section_nr, i; 224 struct mem_section *ms; 225 struct page *page, *memmap; 226 227 if (!pfn_valid(start_pfn)) 228 return; 229 230 section_nr = pfn_to_section_nr(start_pfn); 231 ms = __nr_to_section(section_nr); 232 233 memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); 234 235 register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION); 236 237 usemap = __nr_to_section(section_nr)->pageblock_flags; 238 page = virt_to_page(usemap); 239 240 mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; 241 242 for (i = 0; i < mapsize; i++, page++) 243 get_page_bootmem(section_nr, page, MIX_SECTION_INFO); 244 } 245 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */ 246 247 void register_page_bootmem_info_node(struct pglist_data *pgdat) 248 { 249 unsigned long i, pfn, end_pfn, nr_pages; 250 int node = pgdat->node_id; 251 struct page *page; 252 struct zone *zone; 253 254 nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT; 255 page = virt_to_page(pgdat); 256 257 for (i = 0; i < nr_pages; i++, page++) 258 get_page_bootmem(node, page, NODE_INFO); 259 260 zone = &pgdat->node_zones[0]; 261 for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) { 262 if (zone_is_initialized(zone)) { 263 nr_pages = zone->wait_table_hash_nr_entries 264 * sizeof(wait_queue_head_t); 265 nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT; 266 page = virt_to_page(zone->wait_table); 267 268 for (i = 0; i < nr_pages; i++, page++) 269 get_page_bootmem(node, page, NODE_INFO); 270 } 271 } 272 273 pfn = pgdat->node_start_pfn; 274 end_pfn = pgdat_end_pfn(pgdat); 275 276 /* register section info */ 277 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 278 /* 279 * Some platforms can assign the same pfn to multiple nodes - on 280 * node0 as well as nodeN. To avoid registering a pfn against 281 * multiple nodes we check that this pfn does not already 282 * reside in some other nodes. 283 */ 284 if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node)) 285 register_page_bootmem_info_section(pfn); 286 } 287 } 288 #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */ 289 290 static void __meminit grow_zone_span(struct zone *zone, unsigned long start_pfn, 291 unsigned long end_pfn) 292 { 293 unsigned long old_zone_end_pfn; 294 295 zone_span_writelock(zone); 296 297 old_zone_end_pfn = zone_end_pfn(zone); 298 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn) 299 zone->zone_start_pfn = start_pfn; 300 301 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - 302 zone->zone_start_pfn; 303 304 zone_span_writeunlock(zone); 305 } 306 307 static void resize_zone(struct zone *zone, unsigned long start_pfn, 308 unsigned long end_pfn) 309 { 310 zone_span_writelock(zone); 311 312 if (end_pfn - start_pfn) { 313 zone->zone_start_pfn = start_pfn; 314 zone->spanned_pages = end_pfn - start_pfn; 315 } else { 316 /* 317 * make it consist as free_area_init_core(), 318 * if spanned_pages = 0, then keep start_pfn = 0 319 */ 320 zone->zone_start_pfn = 0; 321 zone->spanned_pages = 0; 322 } 323 324 zone_span_writeunlock(zone); 325 } 326 327 static void fix_zone_id(struct zone *zone, unsigned long start_pfn, 328 unsigned long end_pfn) 329 { 330 enum zone_type zid = zone_idx(zone); 331 int nid = zone->zone_pgdat->node_id; 332 unsigned long pfn; 333 334 for (pfn = start_pfn; pfn < end_pfn; pfn++) 335 set_page_links(pfn_to_page(pfn), zid, nid, pfn); 336 } 337 338 /* Can fail with -ENOMEM from allocating a wait table with vmalloc() or 339 * alloc_bootmem_node_nopanic()/memblock_virt_alloc_node_nopanic() */ 340 static int __ref ensure_zone_is_initialized(struct zone *zone, 341 unsigned long start_pfn, unsigned long num_pages) 342 { 343 if (!zone_is_initialized(zone)) 344 return init_currently_empty_zone(zone, start_pfn, num_pages); 345 346 return 0; 347 } 348 349 static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2, 350 unsigned long start_pfn, unsigned long end_pfn) 351 { 352 int ret; 353 unsigned long flags; 354 unsigned long z1_start_pfn; 355 356 ret = ensure_zone_is_initialized(z1, start_pfn, end_pfn - start_pfn); 357 if (ret) 358 return ret; 359 360 pgdat_resize_lock(z1->zone_pgdat, &flags); 361 362 /* can't move pfns which are higher than @z2 */ 363 if (end_pfn > zone_end_pfn(z2)) 364 goto out_fail; 365 /* the move out part must be at the left most of @z2 */ 366 if (start_pfn > z2->zone_start_pfn) 367 goto out_fail; 368 /* must included/overlap */ 369 if (end_pfn <= z2->zone_start_pfn) 370 goto out_fail; 371 372 /* use start_pfn for z1's start_pfn if z1 is empty */ 373 if (!zone_is_empty(z1)) 374 z1_start_pfn = z1->zone_start_pfn; 375 else 376 z1_start_pfn = start_pfn; 377 378 resize_zone(z1, z1_start_pfn, end_pfn); 379 resize_zone(z2, end_pfn, zone_end_pfn(z2)); 380 381 pgdat_resize_unlock(z1->zone_pgdat, &flags); 382 383 fix_zone_id(z1, start_pfn, end_pfn); 384 385 return 0; 386 out_fail: 387 pgdat_resize_unlock(z1->zone_pgdat, &flags); 388 return -1; 389 } 390 391 static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2, 392 unsigned long start_pfn, unsigned long end_pfn) 393 { 394 int ret; 395 unsigned long flags; 396 unsigned long z2_end_pfn; 397 398 ret = ensure_zone_is_initialized(z2, start_pfn, end_pfn - start_pfn); 399 if (ret) 400 return ret; 401 402 pgdat_resize_lock(z1->zone_pgdat, &flags); 403 404 /* can't move pfns which are lower than @z1 */ 405 if (z1->zone_start_pfn > start_pfn) 406 goto out_fail; 407 /* the move out part mast at the right most of @z1 */ 408 if (zone_end_pfn(z1) > end_pfn) 409 goto out_fail; 410 /* must included/overlap */ 411 if (start_pfn >= zone_end_pfn(z1)) 412 goto out_fail; 413 414 /* use end_pfn for z2's end_pfn if z2 is empty */ 415 if (!zone_is_empty(z2)) 416 z2_end_pfn = zone_end_pfn(z2); 417 else 418 z2_end_pfn = end_pfn; 419 420 resize_zone(z1, z1->zone_start_pfn, start_pfn); 421 resize_zone(z2, start_pfn, z2_end_pfn); 422 423 pgdat_resize_unlock(z1->zone_pgdat, &flags); 424 425 fix_zone_id(z2, start_pfn, end_pfn); 426 427 return 0; 428 out_fail: 429 pgdat_resize_unlock(z1->zone_pgdat, &flags); 430 return -1; 431 } 432 433 static void __meminit grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn, 434 unsigned long end_pfn) 435 { 436 unsigned long old_pgdat_end_pfn = pgdat_end_pfn(pgdat); 437 438 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn) 439 pgdat->node_start_pfn = start_pfn; 440 441 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - 442 pgdat->node_start_pfn; 443 } 444 445 static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn) 446 { 447 struct pglist_data *pgdat = zone->zone_pgdat; 448 int nr_pages = PAGES_PER_SECTION; 449 int nid = pgdat->node_id; 450 int zone_type; 451 unsigned long flags, pfn; 452 int ret; 453 454 zone_type = zone - pgdat->node_zones; 455 ret = ensure_zone_is_initialized(zone, phys_start_pfn, nr_pages); 456 if (ret) 457 return ret; 458 459 pgdat_resize_lock(zone->zone_pgdat, &flags); 460 grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages); 461 grow_pgdat_span(zone->zone_pgdat, phys_start_pfn, 462 phys_start_pfn + nr_pages); 463 pgdat_resize_unlock(zone->zone_pgdat, &flags); 464 memmap_init_zone(nr_pages, nid, zone_type, 465 phys_start_pfn, MEMMAP_HOTPLUG); 466 467 /* online_page_range is called later and expects pages reserved */ 468 for (pfn = phys_start_pfn; pfn < phys_start_pfn + nr_pages; pfn++) { 469 if (!pfn_valid(pfn)) 470 continue; 471 472 SetPageReserved(pfn_to_page(pfn)); 473 } 474 return 0; 475 } 476 477 static int __meminit __add_section(int nid, struct zone *zone, 478 unsigned long phys_start_pfn) 479 { 480 int ret; 481 482 if (pfn_valid(phys_start_pfn)) 483 return -EEXIST; 484 485 ret = sparse_add_one_section(zone, phys_start_pfn); 486 487 if (ret < 0) 488 return ret; 489 490 ret = __add_zone(zone, phys_start_pfn); 491 492 if (ret < 0) 493 return ret; 494 495 return register_new_memory(nid, __pfn_to_section(phys_start_pfn)); 496 } 497 498 /* 499 * Reasonably generic function for adding memory. It is 500 * expected that archs that support memory hotplug will 501 * call this function after deciding the zone to which to 502 * add the new pages. 503 */ 504 int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn, 505 unsigned long nr_pages) 506 { 507 unsigned long i; 508 int err = 0; 509 int start_sec, end_sec; 510 struct vmem_altmap *altmap; 511 512 /* during initialize mem_map, align hot-added range to section */ 513 start_sec = pfn_to_section_nr(phys_start_pfn); 514 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); 515 516 altmap = to_vmem_altmap((unsigned long) pfn_to_page(phys_start_pfn)); 517 if (altmap) { 518 /* 519 * Validate altmap is within bounds of the total request 520 */ 521 if (altmap->base_pfn != phys_start_pfn 522 || vmem_altmap_offset(altmap) > nr_pages) { 523 pr_warn_once("memory add fail, invalid altmap\n"); 524 return -EINVAL; 525 } 526 altmap->alloc = 0; 527 } 528 529 for (i = start_sec; i <= end_sec; i++) { 530 err = __add_section(nid, zone, section_nr_to_pfn(i)); 531 532 /* 533 * EEXIST is finally dealt with by ioresource collision 534 * check. see add_memory() => register_memory_resource() 535 * Warning will be printed if there is collision. 536 */ 537 if (err && (err != -EEXIST)) 538 break; 539 err = 0; 540 } 541 vmemmap_populate_print_last(); 542 543 return err; 544 } 545 EXPORT_SYMBOL_GPL(__add_pages); 546 547 #ifdef CONFIG_MEMORY_HOTREMOVE 548 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */ 549 static int find_smallest_section_pfn(int nid, struct zone *zone, 550 unsigned long start_pfn, 551 unsigned long end_pfn) 552 { 553 struct mem_section *ms; 554 555 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) { 556 ms = __pfn_to_section(start_pfn); 557 558 if (unlikely(!valid_section(ms))) 559 continue; 560 561 if (unlikely(pfn_to_nid(start_pfn) != nid)) 562 continue; 563 564 if (zone && zone != page_zone(pfn_to_page(start_pfn))) 565 continue; 566 567 return start_pfn; 568 } 569 570 return 0; 571 } 572 573 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */ 574 static int find_biggest_section_pfn(int nid, struct zone *zone, 575 unsigned long start_pfn, 576 unsigned long end_pfn) 577 { 578 struct mem_section *ms; 579 unsigned long pfn; 580 581 /* pfn is the end pfn of a memory section. */ 582 pfn = end_pfn - 1; 583 for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) { 584 ms = __pfn_to_section(pfn); 585 586 if (unlikely(!valid_section(ms))) 587 continue; 588 589 if (unlikely(pfn_to_nid(pfn) != nid)) 590 continue; 591 592 if (zone && zone != page_zone(pfn_to_page(pfn))) 593 continue; 594 595 return pfn; 596 } 597 598 return 0; 599 } 600 601 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, 602 unsigned long end_pfn) 603 { 604 unsigned long zone_start_pfn = zone->zone_start_pfn; 605 unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */ 606 unsigned long zone_end_pfn = z; 607 unsigned long pfn; 608 struct mem_section *ms; 609 int nid = zone_to_nid(zone); 610 611 zone_span_writelock(zone); 612 if (zone_start_pfn == start_pfn) { 613 /* 614 * If the section is smallest section in the zone, it need 615 * shrink zone->zone_start_pfn and zone->zone_spanned_pages. 616 * In this case, we find second smallest valid mem_section 617 * for shrinking zone. 618 */ 619 pfn = find_smallest_section_pfn(nid, zone, end_pfn, 620 zone_end_pfn); 621 if (pfn) { 622 zone->zone_start_pfn = pfn; 623 zone->spanned_pages = zone_end_pfn - pfn; 624 } 625 } else if (zone_end_pfn == end_pfn) { 626 /* 627 * If the section is biggest section in the zone, it need 628 * shrink zone->spanned_pages. 629 * In this case, we find second biggest valid mem_section for 630 * shrinking zone. 631 */ 632 pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn, 633 start_pfn); 634 if (pfn) 635 zone->spanned_pages = pfn - zone_start_pfn + 1; 636 } 637 638 /* 639 * The section is not biggest or smallest mem_section in the zone, it 640 * only creates a hole in the zone. So in this case, we need not 641 * change the zone. But perhaps, the zone has only hole data. Thus 642 * it check the zone has only hole or not. 643 */ 644 pfn = zone_start_pfn; 645 for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) { 646 ms = __pfn_to_section(pfn); 647 648 if (unlikely(!valid_section(ms))) 649 continue; 650 651 if (page_zone(pfn_to_page(pfn)) != zone) 652 continue; 653 654 /* If the section is current section, it continues the loop */ 655 if (start_pfn == pfn) 656 continue; 657 658 /* If we find valid section, we have nothing to do */ 659 zone_span_writeunlock(zone); 660 return; 661 } 662 663 /* The zone has no valid section */ 664 zone->zone_start_pfn = 0; 665 zone->spanned_pages = 0; 666 zone_span_writeunlock(zone); 667 } 668 669 static void shrink_pgdat_span(struct pglist_data *pgdat, 670 unsigned long start_pfn, unsigned long end_pfn) 671 { 672 unsigned long pgdat_start_pfn = pgdat->node_start_pfn; 673 unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */ 674 unsigned long pgdat_end_pfn = p; 675 unsigned long pfn; 676 struct mem_section *ms; 677 int nid = pgdat->node_id; 678 679 if (pgdat_start_pfn == start_pfn) { 680 /* 681 * If the section is smallest section in the pgdat, it need 682 * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages. 683 * In this case, we find second smallest valid mem_section 684 * for shrinking zone. 685 */ 686 pfn = find_smallest_section_pfn(nid, NULL, end_pfn, 687 pgdat_end_pfn); 688 if (pfn) { 689 pgdat->node_start_pfn = pfn; 690 pgdat->node_spanned_pages = pgdat_end_pfn - pfn; 691 } 692 } else if (pgdat_end_pfn == end_pfn) { 693 /* 694 * If the section is biggest section in the pgdat, it need 695 * shrink pgdat->node_spanned_pages. 696 * In this case, we find second biggest valid mem_section for 697 * shrinking zone. 698 */ 699 pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn, 700 start_pfn); 701 if (pfn) 702 pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1; 703 } 704 705 /* 706 * If the section is not biggest or smallest mem_section in the pgdat, 707 * it only creates a hole in the pgdat. So in this case, we need not 708 * change the pgdat. 709 * But perhaps, the pgdat has only hole data. Thus it check the pgdat 710 * has only hole or not. 711 */ 712 pfn = pgdat_start_pfn; 713 for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) { 714 ms = __pfn_to_section(pfn); 715 716 if (unlikely(!valid_section(ms))) 717 continue; 718 719 if (pfn_to_nid(pfn) != nid) 720 continue; 721 722 /* If the section is current section, it continues the loop */ 723 if (start_pfn == pfn) 724 continue; 725 726 /* If we find valid section, we have nothing to do */ 727 return; 728 } 729 730 /* The pgdat has no valid section */ 731 pgdat->node_start_pfn = 0; 732 pgdat->node_spanned_pages = 0; 733 } 734 735 static void __remove_zone(struct zone *zone, unsigned long start_pfn) 736 { 737 struct pglist_data *pgdat = zone->zone_pgdat; 738 int nr_pages = PAGES_PER_SECTION; 739 int zone_type; 740 unsigned long flags; 741 742 zone_type = zone - pgdat->node_zones; 743 744 pgdat_resize_lock(zone->zone_pgdat, &flags); 745 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages); 746 shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages); 747 pgdat_resize_unlock(zone->zone_pgdat, &flags); 748 } 749 750 static int __remove_section(struct zone *zone, struct mem_section *ms, 751 unsigned long map_offset) 752 { 753 unsigned long start_pfn; 754 int scn_nr; 755 int ret = -EINVAL; 756 757 if (!valid_section(ms)) 758 return ret; 759 760 ret = unregister_memory_section(ms); 761 if (ret) 762 return ret; 763 764 scn_nr = __section_nr(ms); 765 start_pfn = section_nr_to_pfn(scn_nr); 766 __remove_zone(zone, start_pfn); 767 768 sparse_remove_one_section(zone, ms, map_offset); 769 return 0; 770 } 771 772 /** 773 * __remove_pages() - remove sections of pages from a zone 774 * @zone: zone from which pages need to be removed 775 * @phys_start_pfn: starting pageframe (must be aligned to start of a section) 776 * @nr_pages: number of pages to remove (must be multiple of section size) 777 * 778 * Generic helper function to remove section mappings and sysfs entries 779 * for the section of the memory we are removing. Caller needs to make 780 * sure that pages are marked reserved and zones are adjust properly by 781 * calling offline_pages(). 782 */ 783 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, 784 unsigned long nr_pages) 785 { 786 unsigned long i; 787 unsigned long map_offset = 0; 788 int sections_to_remove, ret = 0; 789 790 /* In the ZONE_DEVICE case device driver owns the memory region */ 791 if (is_dev_zone(zone)) { 792 struct page *page = pfn_to_page(phys_start_pfn); 793 struct vmem_altmap *altmap; 794 795 altmap = to_vmem_altmap((unsigned long) page); 796 if (altmap) 797 map_offset = vmem_altmap_offset(altmap); 798 } else { 799 resource_size_t start, size; 800 801 start = phys_start_pfn << PAGE_SHIFT; 802 size = nr_pages * PAGE_SIZE; 803 804 ret = release_mem_region_adjustable(&iomem_resource, start, 805 size); 806 if (ret) { 807 resource_size_t endres = start + size - 1; 808 809 pr_warn("Unable to release resource <%pa-%pa> (%d)\n", 810 &start, &endres, ret); 811 } 812 } 813 814 /* 815 * We can only remove entire sections 816 */ 817 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); 818 BUG_ON(nr_pages % PAGES_PER_SECTION); 819 820 sections_to_remove = nr_pages / PAGES_PER_SECTION; 821 for (i = 0; i < sections_to_remove; i++) { 822 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; 823 824 ret = __remove_section(zone, __pfn_to_section(pfn), map_offset); 825 map_offset = 0; 826 if (ret) 827 break; 828 } 829 return ret; 830 } 831 EXPORT_SYMBOL_GPL(__remove_pages); 832 #endif /* CONFIG_MEMORY_HOTREMOVE */ 833 834 int set_online_page_callback(online_page_callback_t callback) 835 { 836 int rc = -EINVAL; 837 838 get_online_mems(); 839 mutex_lock(&online_page_callback_lock); 840 841 if (online_page_callback == generic_online_page) { 842 online_page_callback = callback; 843 rc = 0; 844 } 845 846 mutex_unlock(&online_page_callback_lock); 847 put_online_mems(); 848 849 return rc; 850 } 851 EXPORT_SYMBOL_GPL(set_online_page_callback); 852 853 int restore_online_page_callback(online_page_callback_t callback) 854 { 855 int rc = -EINVAL; 856 857 get_online_mems(); 858 mutex_lock(&online_page_callback_lock); 859 860 if (online_page_callback == callback) { 861 online_page_callback = generic_online_page; 862 rc = 0; 863 } 864 865 mutex_unlock(&online_page_callback_lock); 866 put_online_mems(); 867 868 return rc; 869 } 870 EXPORT_SYMBOL_GPL(restore_online_page_callback); 871 872 void __online_page_set_limits(struct page *page) 873 { 874 } 875 EXPORT_SYMBOL_GPL(__online_page_set_limits); 876 877 void __online_page_increment_counters(struct page *page) 878 { 879 adjust_managed_page_count(page, 1); 880 } 881 EXPORT_SYMBOL_GPL(__online_page_increment_counters); 882 883 void __online_page_free(struct page *page) 884 { 885 __free_reserved_page(page); 886 } 887 EXPORT_SYMBOL_GPL(__online_page_free); 888 889 static void generic_online_page(struct page *page) 890 { 891 __online_page_set_limits(page); 892 __online_page_increment_counters(page); 893 __online_page_free(page); 894 } 895 896 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, 897 void *arg) 898 { 899 unsigned long i; 900 unsigned long onlined_pages = *(unsigned long *)arg; 901 struct page *page; 902 if (PageReserved(pfn_to_page(start_pfn))) 903 for (i = 0; i < nr_pages; i++) { 904 page = pfn_to_page(start_pfn + i); 905 (*online_page_callback)(page); 906 onlined_pages++; 907 } 908 *(unsigned long *)arg = onlined_pages; 909 return 0; 910 } 911 912 #ifdef CONFIG_MOVABLE_NODE 913 /* 914 * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have 915 * normal memory. 916 */ 917 static bool can_online_high_movable(struct zone *zone) 918 { 919 return true; 920 } 921 #else /* CONFIG_MOVABLE_NODE */ 922 /* ensure every online node has NORMAL memory */ 923 static bool can_online_high_movable(struct zone *zone) 924 { 925 return node_state(zone_to_nid(zone), N_NORMAL_MEMORY); 926 } 927 #endif /* CONFIG_MOVABLE_NODE */ 928 929 /* check which state of node_states will be changed when online memory */ 930 static void node_states_check_changes_online(unsigned long nr_pages, 931 struct zone *zone, struct memory_notify *arg) 932 { 933 int nid = zone_to_nid(zone); 934 enum zone_type zone_last = ZONE_NORMAL; 935 936 /* 937 * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY] 938 * contains nodes which have zones of 0...ZONE_NORMAL, 939 * set zone_last to ZONE_NORMAL. 940 * 941 * If we don't have HIGHMEM nor movable node, 942 * node_states[N_NORMAL_MEMORY] contains nodes which have zones of 943 * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE. 944 */ 945 if (N_MEMORY == N_NORMAL_MEMORY) 946 zone_last = ZONE_MOVABLE; 947 948 /* 949 * if the memory to be online is in a zone of 0...zone_last, and 950 * the zones of 0...zone_last don't have memory before online, we will 951 * need to set the node to node_states[N_NORMAL_MEMORY] after 952 * the memory is online. 953 */ 954 if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY)) 955 arg->status_change_nid_normal = nid; 956 else 957 arg->status_change_nid_normal = -1; 958 959 #ifdef CONFIG_HIGHMEM 960 /* 961 * If we have movable node, node_states[N_HIGH_MEMORY] 962 * contains nodes which have zones of 0...ZONE_HIGHMEM, 963 * set zone_last to ZONE_HIGHMEM. 964 * 965 * If we don't have movable node, node_states[N_NORMAL_MEMORY] 966 * contains nodes which have zones of 0...ZONE_MOVABLE, 967 * set zone_last to ZONE_MOVABLE. 968 */ 969 zone_last = ZONE_HIGHMEM; 970 if (N_MEMORY == N_HIGH_MEMORY) 971 zone_last = ZONE_MOVABLE; 972 973 if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY)) 974 arg->status_change_nid_high = nid; 975 else 976 arg->status_change_nid_high = -1; 977 #else 978 arg->status_change_nid_high = arg->status_change_nid_normal; 979 #endif 980 981 /* 982 * if the node don't have memory befor online, we will need to 983 * set the node to node_states[N_MEMORY] after the memory 984 * is online. 985 */ 986 if (!node_state(nid, N_MEMORY)) 987 arg->status_change_nid = nid; 988 else 989 arg->status_change_nid = -1; 990 } 991 992 static void node_states_set_node(int node, struct memory_notify *arg) 993 { 994 if (arg->status_change_nid_normal >= 0) 995 node_set_state(node, N_NORMAL_MEMORY); 996 997 if (arg->status_change_nid_high >= 0) 998 node_set_state(node, N_HIGH_MEMORY); 999 1000 node_set_state(node, N_MEMORY); 1001 } 1002 1003 1004 /* Must be protected by mem_hotplug_begin() */ 1005 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type) 1006 { 1007 unsigned long flags; 1008 unsigned long onlined_pages = 0; 1009 struct zone *zone; 1010 int need_zonelists_rebuild = 0; 1011 int nid; 1012 int ret; 1013 struct memory_notify arg; 1014 1015 /* 1016 * This doesn't need a lock to do pfn_to_page(). 1017 * The section can't be removed here because of the 1018 * memory_block->state_mutex. 1019 */ 1020 zone = page_zone(pfn_to_page(pfn)); 1021 1022 if ((zone_idx(zone) > ZONE_NORMAL || 1023 online_type == MMOP_ONLINE_MOVABLE) && 1024 !can_online_high_movable(zone)) 1025 return -EINVAL; 1026 1027 if (online_type == MMOP_ONLINE_KERNEL && 1028 zone_idx(zone) == ZONE_MOVABLE) { 1029 if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) 1030 return -EINVAL; 1031 } 1032 if (online_type == MMOP_ONLINE_MOVABLE && 1033 zone_idx(zone) == ZONE_MOVABLE - 1) { 1034 if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) 1035 return -EINVAL; 1036 } 1037 1038 /* Previous code may changed the zone of the pfn range */ 1039 zone = page_zone(pfn_to_page(pfn)); 1040 1041 arg.start_pfn = pfn; 1042 arg.nr_pages = nr_pages; 1043 node_states_check_changes_online(nr_pages, zone, &arg); 1044 1045 nid = pfn_to_nid(pfn); 1046 1047 ret = memory_notify(MEM_GOING_ONLINE, &arg); 1048 ret = notifier_to_errno(ret); 1049 if (ret) { 1050 memory_notify(MEM_CANCEL_ONLINE, &arg); 1051 return ret; 1052 } 1053 /* 1054 * If this zone is not populated, then it is not in zonelist. 1055 * This means the page allocator ignores this zone. 1056 * So, zonelist must be updated after online. 1057 */ 1058 mutex_lock(&zonelists_mutex); 1059 if (!populated_zone(zone)) { 1060 need_zonelists_rebuild = 1; 1061 build_all_zonelists(NULL, zone); 1062 } 1063 1064 ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages, 1065 online_pages_range); 1066 if (ret) { 1067 if (need_zonelists_rebuild) 1068 zone_pcp_reset(zone); 1069 mutex_unlock(&zonelists_mutex); 1070 printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n", 1071 (unsigned long long) pfn << PAGE_SHIFT, 1072 (((unsigned long long) pfn + nr_pages) 1073 << PAGE_SHIFT) - 1); 1074 memory_notify(MEM_CANCEL_ONLINE, &arg); 1075 return ret; 1076 } 1077 1078 zone->present_pages += onlined_pages; 1079 1080 pgdat_resize_lock(zone->zone_pgdat, &flags); 1081 zone->zone_pgdat->node_present_pages += onlined_pages; 1082 pgdat_resize_unlock(zone->zone_pgdat, &flags); 1083 1084 if (onlined_pages) { 1085 node_states_set_node(zone_to_nid(zone), &arg); 1086 if (need_zonelists_rebuild) 1087 build_all_zonelists(NULL, NULL); 1088 else 1089 zone_pcp_update(zone); 1090 } 1091 1092 mutex_unlock(&zonelists_mutex); 1093 1094 init_per_zone_wmark_min(); 1095 1096 if (onlined_pages) 1097 kswapd_run(zone_to_nid(zone)); 1098 1099 vm_total_pages = nr_free_pagecache_pages(); 1100 1101 writeback_set_ratelimit(); 1102 1103 if (onlined_pages) 1104 memory_notify(MEM_ONLINE, &arg); 1105 return 0; 1106 } 1107 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 1108 1109 static void reset_node_present_pages(pg_data_t *pgdat) 1110 { 1111 struct zone *z; 1112 1113 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) 1114 z->present_pages = 0; 1115 1116 pgdat->node_present_pages = 0; 1117 } 1118 1119 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 1120 static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) 1121 { 1122 struct pglist_data *pgdat; 1123 unsigned long zones_size[MAX_NR_ZONES] = {0}; 1124 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 1125 unsigned long start_pfn = PFN_DOWN(start); 1126 1127 pgdat = NODE_DATA(nid); 1128 if (!pgdat) { 1129 pgdat = arch_alloc_nodedata(nid); 1130 if (!pgdat) 1131 return NULL; 1132 1133 arch_refresh_nodedata(nid, pgdat); 1134 } else { 1135 /* Reset the nr_zones and classzone_idx to 0 before reuse */ 1136 pgdat->nr_zones = 0; 1137 pgdat->classzone_idx = 0; 1138 } 1139 1140 /* we can use NODE_DATA(nid) from here */ 1141 1142 /* init node's zones as empty zones, we don't have any present pages.*/ 1143 free_area_init_node(nid, zones_size, start_pfn, zholes_size); 1144 1145 /* 1146 * The node we allocated has no zone fallback lists. For avoiding 1147 * to access not-initialized zonelist, build here. 1148 */ 1149 mutex_lock(&zonelists_mutex); 1150 build_all_zonelists(pgdat, NULL); 1151 mutex_unlock(&zonelists_mutex); 1152 1153 /* 1154 * zone->managed_pages is set to an approximate value in 1155 * free_area_init_core(), which will cause 1156 * /sys/device/system/node/nodeX/meminfo has wrong data. 1157 * So reset it to 0 before any memory is onlined. 1158 */ 1159 reset_node_managed_pages(pgdat); 1160 1161 /* 1162 * When memory is hot-added, all the memory is in offline state. So 1163 * clear all zones' present_pages because they will be updated in 1164 * online_pages() and offline_pages(). 1165 */ 1166 reset_node_present_pages(pgdat); 1167 1168 return pgdat; 1169 } 1170 1171 static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 1172 { 1173 arch_refresh_nodedata(nid, NULL); 1174 arch_free_nodedata(pgdat); 1175 return; 1176 } 1177 1178 1179 /** 1180 * try_online_node - online a node if offlined 1181 * 1182 * called by cpu_up() to online a node without onlined memory. 1183 */ 1184 int try_online_node(int nid) 1185 { 1186 pg_data_t *pgdat; 1187 int ret; 1188 1189 if (node_online(nid)) 1190 return 0; 1191 1192 mem_hotplug_begin(); 1193 pgdat = hotadd_new_pgdat(nid, 0); 1194 if (!pgdat) { 1195 pr_err("Cannot online node %d due to NULL pgdat\n", nid); 1196 ret = -ENOMEM; 1197 goto out; 1198 } 1199 node_set_online(nid); 1200 ret = register_one_node(nid); 1201 BUG_ON(ret); 1202 1203 if (pgdat->node_zonelists->_zonerefs->zone == NULL) { 1204 mutex_lock(&zonelists_mutex); 1205 build_all_zonelists(NULL, NULL); 1206 mutex_unlock(&zonelists_mutex); 1207 } 1208 1209 out: 1210 mem_hotplug_done(); 1211 return ret; 1212 } 1213 1214 static int check_hotplug_memory_range(u64 start, u64 size) 1215 { 1216 u64 start_pfn = PFN_DOWN(start); 1217 u64 nr_pages = size >> PAGE_SHIFT; 1218 1219 /* Memory range must be aligned with section */ 1220 if ((start_pfn & ~PAGE_SECTION_MASK) || 1221 (nr_pages % PAGES_PER_SECTION) || (!nr_pages)) { 1222 pr_err("Section-unaligned hotplug range: start 0x%llx, size 0x%llx\n", 1223 (unsigned long long)start, 1224 (unsigned long long)size); 1225 return -EINVAL; 1226 } 1227 1228 return 0; 1229 } 1230 1231 /* 1232 * If movable zone has already been setup, newly added memory should be check. 1233 * If its address is higher than movable zone, it should be added as movable. 1234 * Without this check, movable zone may overlap with other zone. 1235 */ 1236 static int should_add_memory_movable(int nid, u64 start, u64 size) 1237 { 1238 unsigned long start_pfn = start >> PAGE_SHIFT; 1239 pg_data_t *pgdat = NODE_DATA(nid); 1240 struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE; 1241 1242 if (zone_is_empty(movable_zone)) 1243 return 0; 1244 1245 if (movable_zone->zone_start_pfn <= start_pfn) 1246 return 1; 1247 1248 return 0; 1249 } 1250 1251 int zone_for_memory(int nid, u64 start, u64 size, int zone_default, 1252 bool for_device) 1253 { 1254 #ifdef CONFIG_ZONE_DEVICE 1255 if (for_device) 1256 return ZONE_DEVICE; 1257 #endif 1258 if (should_add_memory_movable(nid, start, size)) 1259 return ZONE_MOVABLE; 1260 1261 return zone_default; 1262 } 1263 1264 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 1265 int __ref add_memory_resource(int nid, struct resource *res) 1266 { 1267 u64 start, size; 1268 pg_data_t *pgdat = NULL; 1269 bool new_pgdat; 1270 bool new_node; 1271 int ret; 1272 1273 start = res->start; 1274 size = resource_size(res); 1275 1276 ret = check_hotplug_memory_range(start, size); 1277 if (ret) 1278 return ret; 1279 1280 { /* Stupid hack to suppress address-never-null warning */ 1281 void *p = NODE_DATA(nid); 1282 new_pgdat = !p; 1283 } 1284 1285 mem_hotplug_begin(); 1286 1287 /* 1288 * Add new range to memblock so that when hotadd_new_pgdat() is called 1289 * to allocate new pgdat, get_pfn_range_for_nid() will be able to find 1290 * this new range and calculate total pages correctly. The range will 1291 * be removed at hot-remove time. 1292 */ 1293 memblock_add_node(start, size, nid); 1294 1295 new_node = !node_online(nid); 1296 if (new_node) { 1297 pgdat = hotadd_new_pgdat(nid, start); 1298 ret = -ENOMEM; 1299 if (!pgdat) 1300 goto error; 1301 } 1302 1303 /* call arch's memory hotadd */ 1304 ret = arch_add_memory(nid, start, size, false); 1305 1306 if (ret < 0) 1307 goto error; 1308 1309 /* we online node here. we can't roll back from here. */ 1310 node_set_online(nid); 1311 1312 if (new_node) { 1313 ret = register_one_node(nid); 1314 /* 1315 * If sysfs file of new node can't create, cpu on the node 1316 * can't be hot-added. There is no rollback way now. 1317 * So, check by BUG_ON() to catch it reluctantly.. 1318 */ 1319 BUG_ON(ret); 1320 } 1321 1322 /* create new memmap entry */ 1323 firmware_map_add_hotplug(start, start + size, "System RAM"); 1324 1325 goto out; 1326 1327 error: 1328 /* rollback pgdat allocation and others */ 1329 if (new_pgdat) 1330 rollback_node_hotadd(nid, pgdat); 1331 memblock_remove(start, size); 1332 1333 out: 1334 mem_hotplug_done(); 1335 return ret; 1336 } 1337 EXPORT_SYMBOL_GPL(add_memory_resource); 1338 1339 int __ref add_memory(int nid, u64 start, u64 size) 1340 { 1341 struct resource *res; 1342 int ret; 1343 1344 res = register_memory_resource(start, size); 1345 if (IS_ERR(res)) 1346 return PTR_ERR(res); 1347 1348 ret = add_memory_resource(nid, res); 1349 if (ret < 0) 1350 release_memory_resource(res); 1351 return ret; 1352 } 1353 EXPORT_SYMBOL_GPL(add_memory); 1354 1355 #ifdef CONFIG_MEMORY_HOTREMOVE 1356 /* 1357 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy 1358 * set and the size of the free page is given by page_order(). Using this, 1359 * the function determines if the pageblock contains only free pages. 1360 * Due to buddy contraints, a free page at least the size of a pageblock will 1361 * be located at the start of the pageblock 1362 */ 1363 static inline int pageblock_free(struct page *page) 1364 { 1365 return PageBuddy(page) && page_order(page) >= pageblock_order; 1366 } 1367 1368 /* Return the start of the next active pageblock after a given page */ 1369 static struct page *next_active_pageblock(struct page *page) 1370 { 1371 /* Ensure the starting page is pageblock-aligned */ 1372 BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1)); 1373 1374 /* If the entire pageblock is free, move to the end of free page */ 1375 if (pageblock_free(page)) { 1376 int order; 1377 /* be careful. we don't have locks, page_order can be changed.*/ 1378 order = page_order(page); 1379 if ((order < MAX_ORDER) && (order >= pageblock_order)) 1380 return page + (1 << order); 1381 } 1382 1383 return page + pageblock_nr_pages; 1384 } 1385 1386 /* Checks if this range of memory is likely to be hot-removable. */ 1387 int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) 1388 { 1389 struct page *page = pfn_to_page(start_pfn); 1390 struct page *end_page = page + nr_pages; 1391 1392 /* Check the starting page of each pageblock within the range */ 1393 for (; page < end_page; page = next_active_pageblock(page)) { 1394 if (!is_pageblock_removable_nolock(page)) 1395 return 0; 1396 cond_resched(); 1397 } 1398 1399 /* All pageblocks in the memory block are likely to be hot-removable */ 1400 return 1; 1401 } 1402 1403 /* 1404 * Confirm all pages in a range [start, end) is belongs to the same zone. 1405 */ 1406 int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) 1407 { 1408 unsigned long pfn, sec_end_pfn; 1409 struct zone *zone = NULL; 1410 struct page *page; 1411 int i; 1412 for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn); 1413 pfn < end_pfn; 1414 pfn = sec_end_pfn + 1, sec_end_pfn += PAGES_PER_SECTION) { 1415 /* Make sure the memory section is present first */ 1416 if (!present_section_nr(pfn_to_section_nr(pfn))) 1417 continue; 1418 for (; pfn < sec_end_pfn && pfn < end_pfn; 1419 pfn += MAX_ORDER_NR_PAGES) { 1420 i = 0; 1421 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 1422 while ((i < MAX_ORDER_NR_PAGES) && 1423 !pfn_valid_within(pfn + i)) 1424 i++; 1425 if (i == MAX_ORDER_NR_PAGES) 1426 continue; 1427 page = pfn_to_page(pfn + i); 1428 if (zone && page_zone(page) != zone) 1429 return 0; 1430 zone = page_zone(page); 1431 } 1432 } 1433 return 1; 1434 } 1435 1436 /* 1437 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages 1438 * and hugepages). We scan pfn because it's much easier than scanning over 1439 * linked list. This function returns the pfn of the first found movable 1440 * page if it's found, otherwise 0. 1441 */ 1442 static unsigned long scan_movable_pages(unsigned long start, unsigned long end) 1443 { 1444 unsigned long pfn; 1445 struct page *page; 1446 for (pfn = start; pfn < end; pfn++) { 1447 if (pfn_valid(pfn)) { 1448 page = pfn_to_page(pfn); 1449 if (PageLRU(page)) 1450 return pfn; 1451 if (PageHuge(page)) { 1452 if (page_huge_active(page)) 1453 return pfn; 1454 else 1455 pfn = round_up(pfn + 1, 1456 1 << compound_order(page)) - 1; 1457 } 1458 } 1459 } 1460 return 0; 1461 } 1462 1463 #define NR_OFFLINE_AT_ONCE_PAGES (256) 1464 static int 1465 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 1466 { 1467 unsigned long pfn; 1468 struct page *page; 1469 int move_pages = NR_OFFLINE_AT_ONCE_PAGES; 1470 int not_managed = 0; 1471 int ret = 0; 1472 LIST_HEAD(source); 1473 1474 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { 1475 if (!pfn_valid(pfn)) 1476 continue; 1477 page = pfn_to_page(pfn); 1478 1479 if (PageHuge(page)) { 1480 struct page *head = compound_head(page); 1481 pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1; 1482 if (compound_order(head) > PFN_SECTION_SHIFT) { 1483 ret = -EBUSY; 1484 break; 1485 } 1486 if (isolate_huge_page(page, &source)) 1487 move_pages -= 1 << compound_order(head); 1488 continue; 1489 } 1490 1491 if (!get_page_unless_zero(page)) 1492 continue; 1493 /* 1494 * We can skip free pages. And we can only deal with pages on 1495 * LRU. 1496 */ 1497 ret = isolate_lru_page(page); 1498 if (!ret) { /* Success */ 1499 put_page(page); 1500 list_add_tail(&page->lru, &source); 1501 move_pages--; 1502 inc_zone_page_state(page, NR_ISOLATED_ANON + 1503 page_is_file_cache(page)); 1504 1505 } else { 1506 #ifdef CONFIG_DEBUG_VM 1507 printk(KERN_ALERT "removing pfn %lx from LRU failed\n", 1508 pfn); 1509 dump_page(page, "failed to remove from LRU"); 1510 #endif 1511 put_page(page); 1512 /* Because we don't have big zone->lock. we should 1513 check this again here. */ 1514 if (page_count(page)) { 1515 not_managed++; 1516 ret = -EBUSY; 1517 break; 1518 } 1519 } 1520 } 1521 if (!list_empty(&source)) { 1522 if (not_managed) { 1523 putback_movable_pages(&source); 1524 goto out; 1525 } 1526 1527 /* 1528 * alloc_migrate_target should be improooooved!! 1529 * migrate_pages returns # of failed pages. 1530 */ 1531 ret = migrate_pages(&source, alloc_migrate_target, NULL, 0, 1532 MIGRATE_SYNC, MR_MEMORY_HOTPLUG); 1533 if (ret) 1534 putback_movable_pages(&source); 1535 } 1536 out: 1537 return ret; 1538 } 1539 1540 /* 1541 * remove from free_area[] and mark all as Reserved. 1542 */ 1543 static int 1544 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, 1545 void *data) 1546 { 1547 __offline_isolated_pages(start, start + nr_pages); 1548 return 0; 1549 } 1550 1551 static void 1552 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 1553 { 1554 walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL, 1555 offline_isolated_pages_cb); 1556 } 1557 1558 /* 1559 * Check all pages in range, recoreded as memory resource, are isolated. 1560 */ 1561 static int 1562 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, 1563 void *data) 1564 { 1565 int ret; 1566 long offlined = *(long *)data; 1567 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true); 1568 offlined = nr_pages; 1569 if (!ret) 1570 *(long *)data += offlined; 1571 return ret; 1572 } 1573 1574 static long 1575 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) 1576 { 1577 long offlined = 0; 1578 int ret; 1579 1580 ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined, 1581 check_pages_isolated_cb); 1582 if (ret < 0) 1583 offlined = (long)ret; 1584 return offlined; 1585 } 1586 1587 #ifdef CONFIG_MOVABLE_NODE 1588 /* 1589 * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have 1590 * normal memory. 1591 */ 1592 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages) 1593 { 1594 return true; 1595 } 1596 #else /* CONFIG_MOVABLE_NODE */ 1597 /* ensure the node has NORMAL memory if it is still online */ 1598 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages) 1599 { 1600 struct pglist_data *pgdat = zone->zone_pgdat; 1601 unsigned long present_pages = 0; 1602 enum zone_type zt; 1603 1604 for (zt = 0; zt <= ZONE_NORMAL; zt++) 1605 present_pages += pgdat->node_zones[zt].present_pages; 1606 1607 if (present_pages > nr_pages) 1608 return true; 1609 1610 present_pages = 0; 1611 for (; zt <= ZONE_MOVABLE; zt++) 1612 present_pages += pgdat->node_zones[zt].present_pages; 1613 1614 /* 1615 * we can't offline the last normal memory until all 1616 * higher memory is offlined. 1617 */ 1618 return present_pages == 0; 1619 } 1620 #endif /* CONFIG_MOVABLE_NODE */ 1621 1622 static int __init cmdline_parse_movable_node(char *p) 1623 { 1624 #ifdef CONFIG_MOVABLE_NODE 1625 /* 1626 * Memory used by the kernel cannot be hot-removed because Linux 1627 * cannot migrate the kernel pages. When memory hotplug is 1628 * enabled, we should prevent memblock from allocating memory 1629 * for the kernel. 1630 * 1631 * ACPI SRAT records all hotpluggable memory ranges. But before 1632 * SRAT is parsed, we don't know about it. 1633 * 1634 * The kernel image is loaded into memory at very early time. We 1635 * cannot prevent this anyway. So on NUMA system, we set any 1636 * node the kernel resides in as un-hotpluggable. 1637 * 1638 * Since on modern servers, one node could have double-digit 1639 * gigabytes memory, we can assume the memory around the kernel 1640 * image is also un-hotpluggable. So before SRAT is parsed, just 1641 * allocate memory near the kernel image to try the best to keep 1642 * the kernel away from hotpluggable memory. 1643 */ 1644 memblock_set_bottom_up(true); 1645 movable_node_enabled = true; 1646 #else 1647 pr_warn("movable_node option not supported\n"); 1648 #endif 1649 return 0; 1650 } 1651 early_param("movable_node", cmdline_parse_movable_node); 1652 1653 /* check which state of node_states will be changed when offline memory */ 1654 static void node_states_check_changes_offline(unsigned long nr_pages, 1655 struct zone *zone, struct memory_notify *arg) 1656 { 1657 struct pglist_data *pgdat = zone->zone_pgdat; 1658 unsigned long present_pages = 0; 1659 enum zone_type zt, zone_last = ZONE_NORMAL; 1660 1661 /* 1662 * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY] 1663 * contains nodes which have zones of 0...ZONE_NORMAL, 1664 * set zone_last to ZONE_NORMAL. 1665 * 1666 * If we don't have HIGHMEM nor movable node, 1667 * node_states[N_NORMAL_MEMORY] contains nodes which have zones of 1668 * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE. 1669 */ 1670 if (N_MEMORY == N_NORMAL_MEMORY) 1671 zone_last = ZONE_MOVABLE; 1672 1673 /* 1674 * check whether node_states[N_NORMAL_MEMORY] will be changed. 1675 * If the memory to be offline is in a zone of 0...zone_last, 1676 * and it is the last present memory, 0...zone_last will 1677 * become empty after offline , thus we can determind we will 1678 * need to clear the node from node_states[N_NORMAL_MEMORY]. 1679 */ 1680 for (zt = 0; zt <= zone_last; zt++) 1681 present_pages += pgdat->node_zones[zt].present_pages; 1682 if (zone_idx(zone) <= zone_last && nr_pages >= present_pages) 1683 arg->status_change_nid_normal = zone_to_nid(zone); 1684 else 1685 arg->status_change_nid_normal = -1; 1686 1687 #ifdef CONFIG_HIGHMEM 1688 /* 1689 * If we have movable node, node_states[N_HIGH_MEMORY] 1690 * contains nodes which have zones of 0...ZONE_HIGHMEM, 1691 * set zone_last to ZONE_HIGHMEM. 1692 * 1693 * If we don't have movable node, node_states[N_NORMAL_MEMORY] 1694 * contains nodes which have zones of 0...ZONE_MOVABLE, 1695 * set zone_last to ZONE_MOVABLE. 1696 */ 1697 zone_last = ZONE_HIGHMEM; 1698 if (N_MEMORY == N_HIGH_MEMORY) 1699 zone_last = ZONE_MOVABLE; 1700 1701 for (; zt <= zone_last; zt++) 1702 present_pages += pgdat->node_zones[zt].present_pages; 1703 if (zone_idx(zone) <= zone_last && nr_pages >= present_pages) 1704 arg->status_change_nid_high = zone_to_nid(zone); 1705 else 1706 arg->status_change_nid_high = -1; 1707 #else 1708 arg->status_change_nid_high = arg->status_change_nid_normal; 1709 #endif 1710 1711 /* 1712 * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE 1713 */ 1714 zone_last = ZONE_MOVABLE; 1715 1716 /* 1717 * check whether node_states[N_HIGH_MEMORY] will be changed 1718 * If we try to offline the last present @nr_pages from the node, 1719 * we can determind we will need to clear the node from 1720 * node_states[N_HIGH_MEMORY]. 1721 */ 1722 for (; zt <= zone_last; zt++) 1723 present_pages += pgdat->node_zones[zt].present_pages; 1724 if (nr_pages >= present_pages) 1725 arg->status_change_nid = zone_to_nid(zone); 1726 else 1727 arg->status_change_nid = -1; 1728 } 1729 1730 static void node_states_clear_node(int node, struct memory_notify *arg) 1731 { 1732 if (arg->status_change_nid_normal >= 0) 1733 node_clear_state(node, N_NORMAL_MEMORY); 1734 1735 if ((N_MEMORY != N_NORMAL_MEMORY) && 1736 (arg->status_change_nid_high >= 0)) 1737 node_clear_state(node, N_HIGH_MEMORY); 1738 1739 if ((N_MEMORY != N_HIGH_MEMORY) && 1740 (arg->status_change_nid >= 0)) 1741 node_clear_state(node, N_MEMORY); 1742 } 1743 1744 static int __ref __offline_pages(unsigned long start_pfn, 1745 unsigned long end_pfn, unsigned long timeout) 1746 { 1747 unsigned long pfn, nr_pages, expire; 1748 long offlined_pages; 1749 int ret, drain, retry_max, node; 1750 unsigned long flags; 1751 struct zone *zone; 1752 struct memory_notify arg; 1753 1754 /* at least, alignment against pageblock is necessary */ 1755 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) 1756 return -EINVAL; 1757 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) 1758 return -EINVAL; 1759 /* This makes hotplug much easier...and readable. 1760 we assume this for now. .*/ 1761 if (!test_pages_in_a_zone(start_pfn, end_pfn)) 1762 return -EINVAL; 1763 1764 zone = page_zone(pfn_to_page(start_pfn)); 1765 node = zone_to_nid(zone); 1766 nr_pages = end_pfn - start_pfn; 1767 1768 if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages)) 1769 return -EINVAL; 1770 1771 /* set above range as isolated */ 1772 ret = start_isolate_page_range(start_pfn, end_pfn, 1773 MIGRATE_MOVABLE, true); 1774 if (ret) 1775 return ret; 1776 1777 arg.start_pfn = start_pfn; 1778 arg.nr_pages = nr_pages; 1779 node_states_check_changes_offline(nr_pages, zone, &arg); 1780 1781 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 1782 ret = notifier_to_errno(ret); 1783 if (ret) 1784 goto failed_removal; 1785 1786 pfn = start_pfn; 1787 expire = jiffies + timeout; 1788 drain = 0; 1789 retry_max = 5; 1790 repeat: 1791 /* start memory hot removal */ 1792 ret = -EAGAIN; 1793 if (time_after(jiffies, expire)) 1794 goto failed_removal; 1795 ret = -EINTR; 1796 if (signal_pending(current)) 1797 goto failed_removal; 1798 ret = 0; 1799 if (drain) { 1800 lru_add_drain_all(); 1801 cond_resched(); 1802 drain_all_pages(zone); 1803 } 1804 1805 pfn = scan_movable_pages(start_pfn, end_pfn); 1806 if (pfn) { /* We have movable pages */ 1807 ret = do_migrate_range(pfn, end_pfn); 1808 if (!ret) { 1809 drain = 1; 1810 goto repeat; 1811 } else { 1812 if (ret < 0) 1813 if (--retry_max == 0) 1814 goto failed_removal; 1815 yield(); 1816 drain = 1; 1817 goto repeat; 1818 } 1819 } 1820 /* drain all zone's lru pagevec, this is asynchronous... */ 1821 lru_add_drain_all(); 1822 yield(); 1823 /* drain pcp pages, this is synchronous. */ 1824 drain_all_pages(zone); 1825 /* 1826 * dissolve free hugepages in the memory block before doing offlining 1827 * actually in order to make hugetlbfs's object counting consistent. 1828 */ 1829 dissolve_free_huge_pages(start_pfn, end_pfn); 1830 /* check again */ 1831 offlined_pages = check_pages_isolated(start_pfn, end_pfn); 1832 if (offlined_pages < 0) { 1833 ret = -EBUSY; 1834 goto failed_removal; 1835 } 1836 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); 1837 /* Ok, all of our target is isolated. 1838 We cannot do rollback at this point. */ 1839 offline_isolated_pages(start_pfn, end_pfn); 1840 /* reset pagetype flags and makes migrate type to be MOVABLE */ 1841 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); 1842 /* removal success */ 1843 adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages); 1844 zone->present_pages -= offlined_pages; 1845 1846 pgdat_resize_lock(zone->zone_pgdat, &flags); 1847 zone->zone_pgdat->node_present_pages -= offlined_pages; 1848 pgdat_resize_unlock(zone->zone_pgdat, &flags); 1849 1850 init_per_zone_wmark_min(); 1851 1852 if (!populated_zone(zone)) { 1853 zone_pcp_reset(zone); 1854 mutex_lock(&zonelists_mutex); 1855 build_all_zonelists(NULL, NULL); 1856 mutex_unlock(&zonelists_mutex); 1857 } else 1858 zone_pcp_update(zone); 1859 1860 node_states_clear_node(node, &arg); 1861 if (arg.status_change_nid >= 0) 1862 kswapd_stop(node); 1863 1864 vm_total_pages = nr_free_pagecache_pages(); 1865 writeback_set_ratelimit(); 1866 1867 memory_notify(MEM_OFFLINE, &arg); 1868 return 0; 1869 1870 failed_removal: 1871 printk(KERN_INFO "memory offlining [mem %#010llx-%#010llx] failed\n", 1872 (unsigned long long) start_pfn << PAGE_SHIFT, 1873 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1); 1874 memory_notify(MEM_CANCEL_OFFLINE, &arg); 1875 /* pushback to free area */ 1876 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); 1877 return ret; 1878 } 1879 1880 /* Must be protected by mem_hotplug_begin() */ 1881 int offline_pages(unsigned long start_pfn, unsigned long nr_pages) 1882 { 1883 return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ); 1884 } 1885 #endif /* CONFIG_MEMORY_HOTREMOVE */ 1886 1887 /** 1888 * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn) 1889 * @start_pfn: start pfn of the memory range 1890 * @end_pfn: end pfn of the memory range 1891 * @arg: argument passed to func 1892 * @func: callback for each memory section walked 1893 * 1894 * This function walks through all present mem sections in range 1895 * [start_pfn, end_pfn) and call func on each mem section. 1896 * 1897 * Returns the return value of func. 1898 */ 1899 int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn, 1900 void *arg, int (*func)(struct memory_block *, void *)) 1901 { 1902 struct memory_block *mem = NULL; 1903 struct mem_section *section; 1904 unsigned long pfn, section_nr; 1905 int ret; 1906 1907 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1908 section_nr = pfn_to_section_nr(pfn); 1909 if (!present_section_nr(section_nr)) 1910 continue; 1911 1912 section = __nr_to_section(section_nr); 1913 /* same memblock? */ 1914 if (mem) 1915 if ((section_nr >= mem->start_section_nr) && 1916 (section_nr <= mem->end_section_nr)) 1917 continue; 1918 1919 mem = find_memory_block_hinted(section, mem); 1920 if (!mem) 1921 continue; 1922 1923 ret = func(mem, arg); 1924 if (ret) { 1925 kobject_put(&mem->dev.kobj); 1926 return ret; 1927 } 1928 } 1929 1930 if (mem) 1931 kobject_put(&mem->dev.kobj); 1932 1933 return 0; 1934 } 1935 1936 #ifdef CONFIG_MEMORY_HOTREMOVE 1937 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg) 1938 { 1939 int ret = !is_memblock_offlined(mem); 1940 1941 if (unlikely(ret)) { 1942 phys_addr_t beginpa, endpa; 1943 1944 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)); 1945 endpa = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1; 1946 pr_warn("removing memory fails, because memory " 1947 "[%pa-%pa] is onlined\n", 1948 &beginpa, &endpa); 1949 } 1950 1951 return ret; 1952 } 1953 1954 static int check_cpu_on_node(pg_data_t *pgdat) 1955 { 1956 int cpu; 1957 1958 for_each_present_cpu(cpu) { 1959 if (cpu_to_node(cpu) == pgdat->node_id) 1960 /* 1961 * the cpu on this node isn't removed, and we can't 1962 * offline this node. 1963 */ 1964 return -EBUSY; 1965 } 1966 1967 return 0; 1968 } 1969 1970 static void unmap_cpu_on_node(pg_data_t *pgdat) 1971 { 1972 #ifdef CONFIG_ACPI_NUMA 1973 int cpu; 1974 1975 for_each_possible_cpu(cpu) 1976 if (cpu_to_node(cpu) == pgdat->node_id) 1977 numa_clear_node(cpu); 1978 #endif 1979 } 1980 1981 static int check_and_unmap_cpu_on_node(pg_data_t *pgdat) 1982 { 1983 int ret; 1984 1985 ret = check_cpu_on_node(pgdat); 1986 if (ret) 1987 return ret; 1988 1989 /* 1990 * the node will be offlined when we come here, so we can clear 1991 * the cpu_to_node() now. 1992 */ 1993 1994 unmap_cpu_on_node(pgdat); 1995 return 0; 1996 } 1997 1998 /** 1999 * try_offline_node 2000 * 2001 * Offline a node if all memory sections and cpus of the node are removed. 2002 * 2003 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 2004 * and online/offline operations before this call. 2005 */ 2006 void try_offline_node(int nid) 2007 { 2008 pg_data_t *pgdat = NODE_DATA(nid); 2009 unsigned long start_pfn = pgdat->node_start_pfn; 2010 unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages; 2011 unsigned long pfn; 2012 int i; 2013 2014 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 2015 unsigned long section_nr = pfn_to_section_nr(pfn); 2016 2017 if (!present_section_nr(section_nr)) 2018 continue; 2019 2020 if (pfn_to_nid(pfn) != nid) 2021 continue; 2022 2023 /* 2024 * some memory sections of this node are not removed, and we 2025 * can't offline node now. 2026 */ 2027 return; 2028 } 2029 2030 if (check_and_unmap_cpu_on_node(pgdat)) 2031 return; 2032 2033 /* 2034 * all memory/cpu of this node are removed, we can offline this 2035 * node now. 2036 */ 2037 node_set_offline(nid); 2038 unregister_one_node(nid); 2039 2040 /* free waittable in each zone */ 2041 for (i = 0; i < MAX_NR_ZONES; i++) { 2042 struct zone *zone = pgdat->node_zones + i; 2043 2044 /* 2045 * wait_table may be allocated from boot memory, 2046 * here only free if it's allocated by vmalloc. 2047 */ 2048 if (is_vmalloc_addr(zone->wait_table)) { 2049 vfree(zone->wait_table); 2050 zone->wait_table = NULL; 2051 } 2052 } 2053 } 2054 EXPORT_SYMBOL(try_offline_node); 2055 2056 /** 2057 * remove_memory 2058 * 2059 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 2060 * and online/offline operations before this call, as required by 2061 * try_offline_node(). 2062 */ 2063 void __ref remove_memory(int nid, u64 start, u64 size) 2064 { 2065 int ret; 2066 2067 BUG_ON(check_hotplug_memory_range(start, size)); 2068 2069 mem_hotplug_begin(); 2070 2071 /* 2072 * All memory blocks must be offlined before removing memory. Check 2073 * whether all memory blocks in question are offline and trigger a BUG() 2074 * if this is not the case. 2075 */ 2076 ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL, 2077 check_memblock_offlined_cb); 2078 if (ret) 2079 BUG(); 2080 2081 /* remove memmap entry */ 2082 firmware_map_remove(start, start + size, "System RAM"); 2083 memblock_free(start, size); 2084 memblock_remove(start, size); 2085 2086 arch_remove_memory(start, size); 2087 2088 try_offline_node(nid); 2089 2090 mem_hotplug_done(); 2091 } 2092 EXPORT_SYMBOL_GPL(remove_memory); 2093 #endif /* CONFIG_MEMORY_HOTREMOVE */ 2094