1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/mm/memory_hotplug.c 4 * 5 * Copyright (C) 6 */ 7 8 #include <linux/stddef.h> 9 #include <linux/mm.h> 10 #include <linux/sched/signal.h> 11 #include <linux/swap.h> 12 #include <linux/interrupt.h> 13 #include <linux/pagemap.h> 14 #include <linux/compiler.h> 15 #include <linux/export.h> 16 #include <linux/pagevec.h> 17 #include <linux/writeback.h> 18 #include <linux/slab.h> 19 #include <linux/sysctl.h> 20 #include <linux/cpu.h> 21 #include <linux/memory.h> 22 #include <linux/memremap.h> 23 #include <linux/memory_hotplug.h> 24 #include <linux/highmem.h> 25 #include <linux/vmalloc.h> 26 #include <linux/ioport.h> 27 #include <linux/delay.h> 28 #include <linux/migrate.h> 29 #include <linux/page-isolation.h> 30 #include <linux/pfn.h> 31 #include <linux/suspend.h> 32 #include <linux/mm_inline.h> 33 #include <linux/firmware-map.h> 34 #include <linux/stop_machine.h> 35 #include <linux/hugetlb.h> 36 #include <linux/memblock.h> 37 #include <linux/compaction.h> 38 #include <linux/rmap.h> 39 40 #include <asm/tlbflush.h> 41 42 #include "internal.h" 43 #include "shuffle.h" 44 45 46 /* 47 * memory_hotplug.memmap_on_memory parameter 48 */ 49 static bool memmap_on_memory __ro_after_init; 50 #ifdef CONFIG_MHP_MEMMAP_ON_MEMORY 51 module_param(memmap_on_memory, bool, 0444); 52 MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug"); 53 #endif 54 55 /* 56 * online_page_callback contains pointer to current page onlining function. 57 * Initially it is generic_online_page(). If it is required it could be 58 * changed by calling set_online_page_callback() for callback registration 59 * and restore_online_page_callback() for generic callback restore. 60 */ 61 62 static online_page_callback_t online_page_callback = generic_online_page; 63 static DEFINE_MUTEX(online_page_callback_lock); 64 65 DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock); 66 67 void get_online_mems(void) 68 { 69 percpu_down_read(&mem_hotplug_lock); 70 } 71 72 void put_online_mems(void) 73 { 74 percpu_up_read(&mem_hotplug_lock); 75 } 76 77 bool movable_node_enabled = false; 78 79 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE 80 int mhp_default_online_type = MMOP_OFFLINE; 81 #else 82 int mhp_default_online_type = MMOP_ONLINE; 83 #endif 84 85 static int __init setup_memhp_default_state(char *str) 86 { 87 const int online_type = mhp_online_type_from_str(str); 88 89 if (online_type >= 0) 90 mhp_default_online_type = online_type; 91 92 return 1; 93 } 94 __setup("memhp_default_state=", setup_memhp_default_state); 95 96 void mem_hotplug_begin(void) 97 { 98 cpus_read_lock(); 99 percpu_down_write(&mem_hotplug_lock); 100 } 101 102 void mem_hotplug_done(void) 103 { 104 percpu_up_write(&mem_hotplug_lock); 105 cpus_read_unlock(); 106 } 107 108 u64 max_mem_size = U64_MAX; 109 110 /* add this memory to iomem resource */ 111 static struct resource *register_memory_resource(u64 start, u64 size, 112 const char *resource_name) 113 { 114 struct resource *res; 115 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; 116 117 if (strcmp(resource_name, "System RAM")) 118 flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED; 119 120 if (!mhp_range_allowed(start, size, true)) 121 return ERR_PTR(-E2BIG); 122 123 /* 124 * Make sure value parsed from 'mem=' only restricts memory adding 125 * while booting, so that memory hotplug won't be impacted. Please 126 * refer to document of 'mem=' in kernel-parameters.txt for more 127 * details. 128 */ 129 if (start + size > max_mem_size && system_state < SYSTEM_RUNNING) 130 return ERR_PTR(-E2BIG); 131 132 /* 133 * Request ownership of the new memory range. This might be 134 * a child of an existing resource that was present but 135 * not marked as busy. 136 */ 137 res = __request_region(&iomem_resource, start, size, 138 resource_name, flags); 139 140 if (!res) { 141 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n", 142 start, start + size); 143 return ERR_PTR(-EEXIST); 144 } 145 return res; 146 } 147 148 static void release_memory_resource(struct resource *res) 149 { 150 if (!res) 151 return; 152 release_resource(res); 153 kfree(res); 154 } 155 156 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE 157 static int check_pfn_span(unsigned long pfn, unsigned long nr_pages, 158 const char *reason) 159 { 160 /* 161 * Disallow all operations smaller than a sub-section and only 162 * allow operations smaller than a section for 163 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range() 164 * enforces a larger memory_block_size_bytes() granularity for 165 * memory that will be marked online, so this check should only 166 * fire for direct arch_{add,remove}_memory() users outside of 167 * add_memory_resource(). 168 */ 169 unsigned long min_align; 170 171 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) 172 min_align = PAGES_PER_SUBSECTION; 173 else 174 min_align = PAGES_PER_SECTION; 175 if (!IS_ALIGNED(pfn, min_align) 176 || !IS_ALIGNED(nr_pages, min_align)) { 177 WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n", 178 reason, pfn, pfn + nr_pages - 1); 179 return -EINVAL; 180 } 181 return 0; 182 } 183 184 /* 185 * Return page for the valid pfn only if the page is online. All pfn 186 * walkers which rely on the fully initialized page->flags and others 187 * should use this rather than pfn_valid && pfn_to_page 188 */ 189 struct page *pfn_to_online_page(unsigned long pfn) 190 { 191 unsigned long nr = pfn_to_section_nr(pfn); 192 struct dev_pagemap *pgmap; 193 struct mem_section *ms; 194 195 if (nr >= NR_MEM_SECTIONS) 196 return NULL; 197 198 ms = __nr_to_section(nr); 199 if (!online_section(ms)) 200 return NULL; 201 202 /* 203 * Save some code text when online_section() + 204 * pfn_section_valid() are sufficient. 205 */ 206 if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn)) 207 return NULL; 208 209 if (!pfn_section_valid(ms, pfn)) 210 return NULL; 211 212 if (!online_device_section(ms)) 213 return pfn_to_page(pfn); 214 215 /* 216 * Slowpath: when ZONE_DEVICE collides with 217 * ZONE_{NORMAL,MOVABLE} within the same section some pfns in 218 * the section may be 'offline' but 'valid'. Only 219 * get_dev_pagemap() can determine sub-section online status. 220 */ 221 pgmap = get_dev_pagemap(pfn, NULL); 222 put_dev_pagemap(pgmap); 223 224 /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */ 225 if (pgmap) 226 return NULL; 227 228 return pfn_to_page(pfn); 229 } 230 EXPORT_SYMBOL_GPL(pfn_to_online_page); 231 232 /* 233 * Reasonably generic function for adding memory. It is 234 * expected that archs that support memory hotplug will 235 * call this function after deciding the zone to which to 236 * add the new pages. 237 */ 238 int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages, 239 struct mhp_params *params) 240 { 241 const unsigned long end_pfn = pfn + nr_pages; 242 unsigned long cur_nr_pages; 243 int err; 244 struct vmem_altmap *altmap = params->altmap; 245 246 if (WARN_ON_ONCE(!params->pgprot.pgprot)) 247 return -EINVAL; 248 249 VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false)); 250 251 if (altmap) { 252 /* 253 * Validate altmap is within bounds of the total request 254 */ 255 if (altmap->base_pfn != pfn 256 || vmem_altmap_offset(altmap) > nr_pages) { 257 pr_warn_once("memory add fail, invalid altmap\n"); 258 return -EINVAL; 259 } 260 altmap->alloc = 0; 261 } 262 263 err = check_pfn_span(pfn, nr_pages, "add"); 264 if (err) 265 return err; 266 267 for (; pfn < end_pfn; pfn += cur_nr_pages) { 268 /* Select all remaining pages up to the next section boundary */ 269 cur_nr_pages = min(end_pfn - pfn, 270 SECTION_ALIGN_UP(pfn + 1) - pfn); 271 err = sparse_add_section(nid, pfn, cur_nr_pages, altmap); 272 if (err) 273 break; 274 cond_resched(); 275 } 276 vmemmap_populate_print_last(); 277 return err; 278 } 279 280 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */ 281 static unsigned long find_smallest_section_pfn(int nid, struct zone *zone, 282 unsigned long start_pfn, 283 unsigned long end_pfn) 284 { 285 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) { 286 if (unlikely(!pfn_to_online_page(start_pfn))) 287 continue; 288 289 if (unlikely(pfn_to_nid(start_pfn) != nid)) 290 continue; 291 292 if (zone != page_zone(pfn_to_page(start_pfn))) 293 continue; 294 295 return start_pfn; 296 } 297 298 return 0; 299 } 300 301 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */ 302 static unsigned long find_biggest_section_pfn(int nid, struct zone *zone, 303 unsigned long start_pfn, 304 unsigned long end_pfn) 305 { 306 unsigned long pfn; 307 308 /* pfn is the end pfn of a memory section. */ 309 pfn = end_pfn - 1; 310 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) { 311 if (unlikely(!pfn_to_online_page(pfn))) 312 continue; 313 314 if (unlikely(pfn_to_nid(pfn) != nid)) 315 continue; 316 317 if (zone != page_zone(pfn_to_page(pfn))) 318 continue; 319 320 return pfn; 321 } 322 323 return 0; 324 } 325 326 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, 327 unsigned long end_pfn) 328 { 329 unsigned long pfn; 330 int nid = zone_to_nid(zone); 331 332 if (zone->zone_start_pfn == start_pfn) { 333 /* 334 * If the section is smallest section in the zone, it need 335 * shrink zone->zone_start_pfn and zone->zone_spanned_pages. 336 * In this case, we find second smallest valid mem_section 337 * for shrinking zone. 338 */ 339 pfn = find_smallest_section_pfn(nid, zone, end_pfn, 340 zone_end_pfn(zone)); 341 if (pfn) { 342 zone->spanned_pages = zone_end_pfn(zone) - pfn; 343 zone->zone_start_pfn = pfn; 344 } else { 345 zone->zone_start_pfn = 0; 346 zone->spanned_pages = 0; 347 } 348 } else if (zone_end_pfn(zone) == end_pfn) { 349 /* 350 * If the section is biggest section in the zone, it need 351 * shrink zone->spanned_pages. 352 * In this case, we find second biggest valid mem_section for 353 * shrinking zone. 354 */ 355 pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn, 356 start_pfn); 357 if (pfn) 358 zone->spanned_pages = pfn - zone->zone_start_pfn + 1; 359 else { 360 zone->zone_start_pfn = 0; 361 zone->spanned_pages = 0; 362 } 363 } 364 } 365 366 static void update_pgdat_span(struct pglist_data *pgdat) 367 { 368 unsigned long node_start_pfn = 0, node_end_pfn = 0; 369 struct zone *zone; 370 371 for (zone = pgdat->node_zones; 372 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) { 373 unsigned long end_pfn = zone_end_pfn(zone); 374 375 /* No need to lock the zones, they can't change. */ 376 if (!zone->spanned_pages) 377 continue; 378 if (!node_end_pfn) { 379 node_start_pfn = zone->zone_start_pfn; 380 node_end_pfn = end_pfn; 381 continue; 382 } 383 384 if (end_pfn > node_end_pfn) 385 node_end_pfn = end_pfn; 386 if (zone->zone_start_pfn < node_start_pfn) 387 node_start_pfn = zone->zone_start_pfn; 388 } 389 390 pgdat->node_start_pfn = node_start_pfn; 391 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn; 392 } 393 394 void __ref remove_pfn_range_from_zone(struct zone *zone, 395 unsigned long start_pfn, 396 unsigned long nr_pages) 397 { 398 const unsigned long end_pfn = start_pfn + nr_pages; 399 struct pglist_data *pgdat = zone->zone_pgdat; 400 unsigned long pfn, cur_nr_pages; 401 402 /* Poison struct pages because they are now uninitialized again. */ 403 for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) { 404 cond_resched(); 405 406 /* Select all remaining pages up to the next section boundary */ 407 cur_nr_pages = 408 min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn); 409 page_init_poison(pfn_to_page(pfn), 410 sizeof(struct page) * cur_nr_pages); 411 } 412 413 #ifdef CONFIG_ZONE_DEVICE 414 /* 415 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So 416 * we will not try to shrink the zones - which is okay as 417 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way. 418 */ 419 if (zone_idx(zone) == ZONE_DEVICE) 420 return; 421 #endif 422 423 clear_zone_contiguous(zone); 424 425 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages); 426 update_pgdat_span(pgdat); 427 428 set_zone_contiguous(zone); 429 } 430 431 static void __remove_section(unsigned long pfn, unsigned long nr_pages, 432 unsigned long map_offset, 433 struct vmem_altmap *altmap) 434 { 435 struct mem_section *ms = __pfn_to_section(pfn); 436 437 if (WARN_ON_ONCE(!valid_section(ms))) 438 return; 439 440 sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap); 441 } 442 443 /** 444 * __remove_pages() - remove sections of pages 445 * @pfn: starting pageframe (must be aligned to start of a section) 446 * @nr_pages: number of pages to remove (must be multiple of section size) 447 * @altmap: alternative device page map or %NULL if default memmap is used 448 * 449 * Generic helper function to remove section mappings and sysfs entries 450 * for the section of the memory we are removing. Caller needs to make 451 * sure that pages are marked reserved and zones are adjust properly by 452 * calling offline_pages(). 453 */ 454 void __remove_pages(unsigned long pfn, unsigned long nr_pages, 455 struct vmem_altmap *altmap) 456 { 457 const unsigned long end_pfn = pfn + nr_pages; 458 unsigned long cur_nr_pages; 459 unsigned long map_offset = 0; 460 461 map_offset = vmem_altmap_offset(altmap); 462 463 if (check_pfn_span(pfn, nr_pages, "remove")) 464 return; 465 466 for (; pfn < end_pfn; pfn += cur_nr_pages) { 467 cond_resched(); 468 /* Select all remaining pages up to the next section boundary */ 469 cur_nr_pages = min(end_pfn - pfn, 470 SECTION_ALIGN_UP(pfn + 1) - pfn); 471 __remove_section(pfn, cur_nr_pages, map_offset, altmap); 472 map_offset = 0; 473 } 474 } 475 476 int set_online_page_callback(online_page_callback_t callback) 477 { 478 int rc = -EINVAL; 479 480 get_online_mems(); 481 mutex_lock(&online_page_callback_lock); 482 483 if (online_page_callback == generic_online_page) { 484 online_page_callback = callback; 485 rc = 0; 486 } 487 488 mutex_unlock(&online_page_callback_lock); 489 put_online_mems(); 490 491 return rc; 492 } 493 EXPORT_SYMBOL_GPL(set_online_page_callback); 494 495 int restore_online_page_callback(online_page_callback_t callback) 496 { 497 int rc = -EINVAL; 498 499 get_online_mems(); 500 mutex_lock(&online_page_callback_lock); 501 502 if (online_page_callback == callback) { 503 online_page_callback = generic_online_page; 504 rc = 0; 505 } 506 507 mutex_unlock(&online_page_callback_lock); 508 put_online_mems(); 509 510 return rc; 511 } 512 EXPORT_SYMBOL_GPL(restore_online_page_callback); 513 514 void generic_online_page(struct page *page, unsigned int order) 515 { 516 /* 517 * Freeing the page with debug_pagealloc enabled will try to unmap it, 518 * so we should map it first. This is better than introducing a special 519 * case in page freeing fast path. 520 */ 521 debug_pagealloc_map_pages(page, 1 << order); 522 __free_pages_core(page, order); 523 totalram_pages_add(1UL << order); 524 #ifdef CONFIG_HIGHMEM 525 if (PageHighMem(page)) 526 totalhigh_pages_add(1UL << order); 527 #endif 528 } 529 EXPORT_SYMBOL_GPL(generic_online_page); 530 531 static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages) 532 { 533 const unsigned long end_pfn = start_pfn + nr_pages; 534 unsigned long pfn; 535 536 /* 537 * Online the pages in MAX_ORDER - 1 aligned chunks. The callback might 538 * decide to not expose all pages to the buddy (e.g., expose them 539 * later). We account all pages as being online and belonging to this 540 * zone ("present"). 541 * When using memmap_on_memory, the range might not be aligned to 542 * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect 543 * this and the first chunk to online will be pageblock_nr_pages. 544 */ 545 for (pfn = start_pfn; pfn < end_pfn;) { 546 int order = min(MAX_ORDER - 1UL, __ffs(pfn)); 547 548 (*online_page_callback)(pfn_to_page(pfn), order); 549 pfn += (1UL << order); 550 } 551 552 /* mark all involved sections as online */ 553 online_mem_sections(start_pfn, end_pfn); 554 } 555 556 /* check which state of node_states will be changed when online memory */ 557 static void node_states_check_changes_online(unsigned long nr_pages, 558 struct zone *zone, struct memory_notify *arg) 559 { 560 int nid = zone_to_nid(zone); 561 562 arg->status_change_nid = NUMA_NO_NODE; 563 arg->status_change_nid_normal = NUMA_NO_NODE; 564 arg->status_change_nid_high = NUMA_NO_NODE; 565 566 if (!node_state(nid, N_MEMORY)) 567 arg->status_change_nid = nid; 568 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY)) 569 arg->status_change_nid_normal = nid; 570 #ifdef CONFIG_HIGHMEM 571 if (zone_idx(zone) <= ZONE_HIGHMEM && !node_state(nid, N_HIGH_MEMORY)) 572 arg->status_change_nid_high = nid; 573 #endif 574 } 575 576 static void node_states_set_node(int node, struct memory_notify *arg) 577 { 578 if (arg->status_change_nid_normal >= 0) 579 node_set_state(node, N_NORMAL_MEMORY); 580 581 if (arg->status_change_nid_high >= 0) 582 node_set_state(node, N_HIGH_MEMORY); 583 584 if (arg->status_change_nid >= 0) 585 node_set_state(node, N_MEMORY); 586 } 587 588 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn, 589 unsigned long nr_pages) 590 { 591 unsigned long old_end_pfn = zone_end_pfn(zone); 592 593 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn) 594 zone->zone_start_pfn = start_pfn; 595 596 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn; 597 } 598 599 static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn, 600 unsigned long nr_pages) 601 { 602 unsigned long old_end_pfn = pgdat_end_pfn(pgdat); 603 604 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn) 605 pgdat->node_start_pfn = start_pfn; 606 607 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn; 608 609 } 610 611 static void section_taint_zone_device(unsigned long pfn) 612 { 613 struct mem_section *ms = __pfn_to_section(pfn); 614 615 ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE; 616 } 617 618 /* 619 * Associate the pfn range with the given zone, initializing the memmaps 620 * and resizing the pgdat/zone data to span the added pages. After this 621 * call, all affected pages are PG_reserved. 622 * 623 * All aligned pageblocks are initialized to the specified migratetype 624 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related 625 * zone stats (e.g., nr_isolate_pageblock) are touched. 626 */ 627 void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, 628 unsigned long nr_pages, 629 struct vmem_altmap *altmap, int migratetype) 630 { 631 struct pglist_data *pgdat = zone->zone_pgdat; 632 int nid = pgdat->node_id; 633 634 clear_zone_contiguous(zone); 635 636 if (zone_is_empty(zone)) 637 init_currently_empty_zone(zone, start_pfn, nr_pages); 638 resize_zone_range(zone, start_pfn, nr_pages); 639 resize_pgdat_range(pgdat, start_pfn, nr_pages); 640 641 /* 642 * Subsection population requires care in pfn_to_online_page(). 643 * Set the taint to enable the slow path detection of 644 * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE} 645 * section. 646 */ 647 if (zone_is_zone_device(zone)) { 648 if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION)) 649 section_taint_zone_device(start_pfn); 650 if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)) 651 section_taint_zone_device(start_pfn + nr_pages); 652 } 653 654 /* 655 * TODO now we have a visible range of pages which are not associated 656 * with their zone properly. Not nice but set_pfnblock_flags_mask 657 * expects the zone spans the pfn range. All the pages in the range 658 * are reserved so nobody should be touching them so we should be safe 659 */ 660 memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0, 661 MEMINIT_HOTPLUG, altmap, migratetype); 662 663 set_zone_contiguous(zone); 664 } 665 666 /* 667 * Returns a default kernel memory zone for the given pfn range. 668 * If no kernel zone covers this pfn range it will automatically go 669 * to the ZONE_NORMAL. 670 */ 671 static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn, 672 unsigned long nr_pages) 673 { 674 struct pglist_data *pgdat = NODE_DATA(nid); 675 int zid; 676 677 for (zid = 0; zid <= ZONE_NORMAL; zid++) { 678 struct zone *zone = &pgdat->node_zones[zid]; 679 680 if (zone_intersects(zone, start_pfn, nr_pages)) 681 return zone; 682 } 683 684 return &pgdat->node_zones[ZONE_NORMAL]; 685 } 686 687 static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn, 688 unsigned long nr_pages) 689 { 690 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn, 691 nr_pages); 692 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 693 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages); 694 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages); 695 696 /* 697 * We inherit the existing zone in a simple case where zones do not 698 * overlap in the given range 699 */ 700 if (in_kernel ^ in_movable) 701 return (in_kernel) ? kernel_zone : movable_zone; 702 703 /* 704 * If the range doesn't belong to any zone or two zones overlap in the 705 * given range then we use movable zone only if movable_node is 706 * enabled because we always online to a kernel zone by default. 707 */ 708 return movable_node_enabled ? movable_zone : kernel_zone; 709 } 710 711 struct zone *zone_for_pfn_range(int online_type, int nid, unsigned start_pfn, 712 unsigned long nr_pages) 713 { 714 if (online_type == MMOP_ONLINE_KERNEL) 715 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages); 716 717 if (online_type == MMOP_ONLINE_MOVABLE) 718 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 719 720 return default_zone_for_pfn(nid, start_pfn, nr_pages); 721 } 722 723 /* 724 * This function should only be called by memory_block_{online,offline}, 725 * and {online,offline}_pages. 726 */ 727 void adjust_present_page_count(struct zone *zone, long nr_pages) 728 { 729 zone->present_pages += nr_pages; 730 zone->zone_pgdat->node_present_pages += nr_pages; 731 } 732 733 int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages, 734 struct zone *zone) 735 { 736 unsigned long end_pfn = pfn + nr_pages; 737 int ret; 738 739 ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); 740 if (ret) 741 return ret; 742 743 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE); 744 745 /* 746 * It might be that the vmemmap_pages fully span sections. If that is 747 * the case, mark those sections online here as otherwise they will be 748 * left offline. 749 */ 750 if (nr_pages >= PAGES_PER_SECTION) 751 online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION)); 752 753 return ret; 754 } 755 756 void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages) 757 { 758 unsigned long end_pfn = pfn + nr_pages; 759 760 /* 761 * It might be that the vmemmap_pages fully span sections. If that is 762 * the case, mark those sections offline here as otherwise they will be 763 * left online. 764 */ 765 if (nr_pages >= PAGES_PER_SECTION) 766 offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION)); 767 768 /* 769 * The pages associated with this vmemmap have been offlined, so 770 * we can reset its state here. 771 */ 772 remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages); 773 kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); 774 } 775 776 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, struct zone *zone) 777 { 778 unsigned long flags; 779 int need_zonelists_rebuild = 0; 780 const int nid = zone_to_nid(zone); 781 int ret; 782 struct memory_notify arg; 783 784 /* 785 * {on,off}lining is constrained to full memory sections (or more 786 * precisely to memory blocks from the user space POV). 787 * memmap_on_memory is an exception because it reserves initial part 788 * of the physical memory space for vmemmaps. That space is pageblock 789 * aligned. 790 */ 791 if (WARN_ON_ONCE(!nr_pages || 792 !IS_ALIGNED(pfn, pageblock_nr_pages) || 793 !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION))) 794 return -EINVAL; 795 796 mem_hotplug_begin(); 797 798 /* associate pfn range with the zone */ 799 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE); 800 801 arg.start_pfn = pfn; 802 arg.nr_pages = nr_pages; 803 node_states_check_changes_online(nr_pages, zone, &arg); 804 805 ret = memory_notify(MEM_GOING_ONLINE, &arg); 806 ret = notifier_to_errno(ret); 807 if (ret) 808 goto failed_addition; 809 810 /* 811 * Fixup the number of isolated pageblocks before marking the sections 812 * onlining, such that undo_isolate_page_range() works correctly. 813 */ 814 spin_lock_irqsave(&zone->lock, flags); 815 zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages; 816 spin_unlock_irqrestore(&zone->lock, flags); 817 818 /* 819 * If this zone is not populated, then it is not in zonelist. 820 * This means the page allocator ignores this zone. 821 * So, zonelist must be updated after online. 822 */ 823 if (!populated_zone(zone)) { 824 need_zonelists_rebuild = 1; 825 setup_zone_pageset(zone); 826 } 827 828 online_pages_range(pfn, nr_pages); 829 adjust_present_page_count(zone, nr_pages); 830 831 node_states_set_node(nid, &arg); 832 if (need_zonelists_rebuild) 833 build_all_zonelists(NULL); 834 835 /* Basic onlining is complete, allow allocation of onlined pages. */ 836 undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE); 837 838 /* 839 * Freshly onlined pages aren't shuffled (e.g., all pages are placed to 840 * the tail of the freelist when undoing isolation). Shuffle the whole 841 * zone to make sure the just onlined pages are properly distributed 842 * across the whole freelist - to create an initial shuffle. 843 */ 844 shuffle_zone(zone); 845 846 /* reinitialise watermarks and update pcp limits */ 847 init_per_zone_wmark_min(); 848 849 kswapd_run(nid); 850 kcompactd_run(nid); 851 852 writeback_set_ratelimit(); 853 854 memory_notify(MEM_ONLINE, &arg); 855 mem_hotplug_done(); 856 return 0; 857 858 failed_addition: 859 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n", 860 (unsigned long long) pfn << PAGE_SHIFT, 861 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1); 862 memory_notify(MEM_CANCEL_ONLINE, &arg); 863 remove_pfn_range_from_zone(zone, pfn, nr_pages); 864 mem_hotplug_done(); 865 return ret; 866 } 867 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 868 869 static void reset_node_present_pages(pg_data_t *pgdat) 870 { 871 struct zone *z; 872 873 for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) 874 z->present_pages = 0; 875 876 pgdat->node_present_pages = 0; 877 } 878 879 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 880 static pg_data_t __ref *hotadd_new_pgdat(int nid) 881 { 882 struct pglist_data *pgdat; 883 884 pgdat = NODE_DATA(nid); 885 if (!pgdat) { 886 pgdat = arch_alloc_nodedata(nid); 887 if (!pgdat) 888 return NULL; 889 890 pgdat->per_cpu_nodestats = 891 alloc_percpu(struct per_cpu_nodestat); 892 arch_refresh_nodedata(nid, pgdat); 893 } else { 894 int cpu; 895 /* 896 * Reset the nr_zones, order and highest_zoneidx before reuse. 897 * Note that kswapd will init kswapd_highest_zoneidx properly 898 * when it starts in the near future. 899 */ 900 pgdat->nr_zones = 0; 901 pgdat->kswapd_order = 0; 902 pgdat->kswapd_highest_zoneidx = 0; 903 for_each_online_cpu(cpu) { 904 struct per_cpu_nodestat *p; 905 906 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu); 907 memset(p, 0, sizeof(*p)); 908 } 909 } 910 911 /* we can use NODE_DATA(nid) from here */ 912 pgdat->node_id = nid; 913 pgdat->node_start_pfn = 0; 914 915 /* init node's zones as empty zones, we don't have any present pages.*/ 916 free_area_init_core_hotplug(nid); 917 918 /* 919 * The node we allocated has no zone fallback lists. For avoiding 920 * to access not-initialized zonelist, build here. 921 */ 922 build_all_zonelists(pgdat); 923 924 /* 925 * When memory is hot-added, all the memory is in offline state. So 926 * clear all zones' present_pages because they will be updated in 927 * online_pages() and offline_pages(). 928 */ 929 reset_node_managed_pages(pgdat); 930 reset_node_present_pages(pgdat); 931 932 return pgdat; 933 } 934 935 static void rollback_node_hotadd(int nid) 936 { 937 pg_data_t *pgdat = NODE_DATA(nid); 938 939 arch_refresh_nodedata(nid, NULL); 940 free_percpu(pgdat->per_cpu_nodestats); 941 arch_free_nodedata(pgdat); 942 } 943 944 945 /* 946 * __try_online_node - online a node if offlined 947 * @nid: the node ID 948 * @set_node_online: Whether we want to online the node 949 * called by cpu_up() to online a node without onlined memory. 950 * 951 * Returns: 952 * 1 -> a new node has been allocated 953 * 0 -> the node is already online 954 * -ENOMEM -> the node could not be allocated 955 */ 956 static int __try_online_node(int nid, bool set_node_online) 957 { 958 pg_data_t *pgdat; 959 int ret = 1; 960 961 if (node_online(nid)) 962 return 0; 963 964 pgdat = hotadd_new_pgdat(nid); 965 if (!pgdat) { 966 pr_err("Cannot online node %d due to NULL pgdat\n", nid); 967 ret = -ENOMEM; 968 goto out; 969 } 970 971 if (set_node_online) { 972 node_set_online(nid); 973 ret = register_one_node(nid); 974 BUG_ON(ret); 975 } 976 out: 977 return ret; 978 } 979 980 /* 981 * Users of this function always want to online/register the node 982 */ 983 int try_online_node(int nid) 984 { 985 int ret; 986 987 mem_hotplug_begin(); 988 ret = __try_online_node(nid, true); 989 mem_hotplug_done(); 990 return ret; 991 } 992 993 static int check_hotplug_memory_range(u64 start, u64 size) 994 { 995 /* memory range must be block size aligned */ 996 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) || 997 !IS_ALIGNED(size, memory_block_size_bytes())) { 998 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx", 999 memory_block_size_bytes(), start, size); 1000 return -EINVAL; 1001 } 1002 1003 return 0; 1004 } 1005 1006 static int online_memory_block(struct memory_block *mem, void *arg) 1007 { 1008 mem->online_type = mhp_default_online_type; 1009 return device_online(&mem->dev); 1010 } 1011 1012 bool mhp_supports_memmap_on_memory(unsigned long size) 1013 { 1014 unsigned long nr_vmemmap_pages = size / PAGE_SIZE; 1015 unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page); 1016 unsigned long remaining_size = size - vmemmap_size; 1017 1018 /* 1019 * Besides having arch support and the feature enabled at runtime, we 1020 * need a few more assumptions to hold true: 1021 * 1022 * a) We span a single memory block: memory onlining/offlinin;g happens 1023 * in memory block granularity. We don't want the vmemmap of online 1024 * memory blocks to reside on offline memory blocks. In the future, 1025 * we might want to support variable-sized memory blocks to make the 1026 * feature more versatile. 1027 * 1028 * b) The vmemmap pages span complete PMDs: We don't want vmemmap code 1029 * to populate memory from the altmap for unrelated parts (i.e., 1030 * other memory blocks) 1031 * 1032 * c) The vmemmap pages (and thereby the pages that will be exposed to 1033 * the buddy) have to cover full pageblocks: memory onlining/offlining 1034 * code requires applicable ranges to be page-aligned, for example, to 1035 * set the migratetypes properly. 1036 * 1037 * TODO: Although we have a check here to make sure that vmemmap pages 1038 * fully populate a PMD, it is not the right place to check for 1039 * this. A much better solution involves improving vmemmap code 1040 * to fallback to base pages when trying to populate vmemmap using 1041 * altmap as an alternative source of memory, and we do not exactly 1042 * populate a single PMD. 1043 */ 1044 return memmap_on_memory && 1045 !hugetlb_free_vmemmap_enabled && 1046 IS_ENABLED(CONFIG_MHP_MEMMAP_ON_MEMORY) && 1047 size == memory_block_size_bytes() && 1048 IS_ALIGNED(vmemmap_size, PMD_SIZE) && 1049 IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT)); 1050 } 1051 1052 /* 1053 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 1054 * and online/offline operations (triggered e.g. by sysfs). 1055 * 1056 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG 1057 */ 1058 int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) 1059 { 1060 struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; 1061 struct vmem_altmap mhp_altmap = {}; 1062 u64 start, size; 1063 bool new_node = false; 1064 int ret; 1065 1066 start = res->start; 1067 size = resource_size(res); 1068 1069 ret = check_hotplug_memory_range(start, size); 1070 if (ret) 1071 return ret; 1072 1073 if (!node_possible(nid)) { 1074 WARN(1, "node %d was absent from the node_possible_map\n", nid); 1075 return -EINVAL; 1076 } 1077 1078 mem_hotplug_begin(); 1079 1080 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) 1081 memblock_add_node(start, size, nid); 1082 1083 ret = __try_online_node(nid, false); 1084 if (ret < 0) 1085 goto error; 1086 new_node = ret; 1087 1088 /* 1089 * Self hosted memmap array 1090 */ 1091 if (mhp_flags & MHP_MEMMAP_ON_MEMORY) { 1092 if (!mhp_supports_memmap_on_memory(size)) { 1093 ret = -EINVAL; 1094 goto error; 1095 } 1096 mhp_altmap.free = PHYS_PFN(size); 1097 mhp_altmap.base_pfn = PHYS_PFN(start); 1098 params.altmap = &mhp_altmap; 1099 } 1100 1101 /* call arch's memory hotadd */ 1102 ret = arch_add_memory(nid, start, size, ¶ms); 1103 if (ret < 0) 1104 goto error; 1105 1106 /* create memory block devices after memory was added */ 1107 ret = create_memory_block_devices(start, size, mhp_altmap.alloc); 1108 if (ret) { 1109 arch_remove_memory(nid, start, size, NULL); 1110 goto error; 1111 } 1112 1113 if (new_node) { 1114 /* If sysfs file of new node can't be created, cpu on the node 1115 * can't be hot-added. There is no rollback way now. 1116 * So, check by BUG_ON() to catch it reluctantly.. 1117 * We online node here. We can't roll back from here. 1118 */ 1119 node_set_online(nid); 1120 ret = __register_one_node(nid); 1121 BUG_ON(ret); 1122 } 1123 1124 /* link memory sections under this node.*/ 1125 link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1), 1126 MEMINIT_HOTPLUG); 1127 1128 /* create new memmap entry */ 1129 if (!strcmp(res->name, "System RAM")) 1130 firmware_map_add_hotplug(start, start + size, "System RAM"); 1131 1132 /* device_online() will take the lock when calling online_pages() */ 1133 mem_hotplug_done(); 1134 1135 /* 1136 * In case we're allowed to merge the resource, flag it and trigger 1137 * merging now that adding succeeded. 1138 */ 1139 if (mhp_flags & MHP_MERGE_RESOURCE) 1140 merge_system_ram_resource(res); 1141 1142 /* online pages if requested */ 1143 if (mhp_default_online_type != MMOP_OFFLINE) 1144 walk_memory_blocks(start, size, NULL, online_memory_block); 1145 1146 return ret; 1147 error: 1148 /* rollback pgdat allocation and others */ 1149 if (new_node) 1150 rollback_node_hotadd(nid); 1151 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) 1152 memblock_remove(start, size); 1153 mem_hotplug_done(); 1154 return ret; 1155 } 1156 1157 /* requires device_hotplug_lock, see add_memory_resource() */ 1158 int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) 1159 { 1160 struct resource *res; 1161 int ret; 1162 1163 res = register_memory_resource(start, size, "System RAM"); 1164 if (IS_ERR(res)) 1165 return PTR_ERR(res); 1166 1167 ret = add_memory_resource(nid, res, mhp_flags); 1168 if (ret < 0) 1169 release_memory_resource(res); 1170 return ret; 1171 } 1172 1173 int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) 1174 { 1175 int rc; 1176 1177 lock_device_hotplug(); 1178 rc = __add_memory(nid, start, size, mhp_flags); 1179 unlock_device_hotplug(); 1180 1181 return rc; 1182 } 1183 EXPORT_SYMBOL_GPL(add_memory); 1184 1185 /* 1186 * Add special, driver-managed memory to the system as system RAM. Such 1187 * memory is not exposed via the raw firmware-provided memmap as system 1188 * RAM, instead, it is detected and added by a driver - during cold boot, 1189 * after a reboot, and after kexec. 1190 * 1191 * Reasons why this memory should not be used for the initial memmap of a 1192 * kexec kernel or for placing kexec images: 1193 * - The booting kernel is in charge of determining how this memory will be 1194 * used (e.g., use persistent memory as system RAM) 1195 * - Coordination with a hypervisor is required before this memory 1196 * can be used (e.g., inaccessible parts). 1197 * 1198 * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided 1199 * memory map") are created. Also, the created memory resource is flagged 1200 * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case 1201 * this memory as well (esp., not place kexec images onto it). 1202 * 1203 * The resource_name (visible via /proc/iomem) has to have the format 1204 * "System RAM ($DRIVER)". 1205 */ 1206 int add_memory_driver_managed(int nid, u64 start, u64 size, 1207 const char *resource_name, mhp_t mhp_flags) 1208 { 1209 struct resource *res; 1210 int rc; 1211 1212 if (!resource_name || 1213 strstr(resource_name, "System RAM (") != resource_name || 1214 resource_name[strlen(resource_name) - 1] != ')') 1215 return -EINVAL; 1216 1217 lock_device_hotplug(); 1218 1219 res = register_memory_resource(start, size, resource_name); 1220 if (IS_ERR(res)) { 1221 rc = PTR_ERR(res); 1222 goto out_unlock; 1223 } 1224 1225 rc = add_memory_resource(nid, res, mhp_flags); 1226 if (rc < 0) 1227 release_memory_resource(res); 1228 1229 out_unlock: 1230 unlock_device_hotplug(); 1231 return rc; 1232 } 1233 EXPORT_SYMBOL_GPL(add_memory_driver_managed); 1234 1235 /* 1236 * Platforms should define arch_get_mappable_range() that provides 1237 * maximum possible addressable physical memory range for which the 1238 * linear mapping could be created. The platform returned address 1239 * range must adhere to these following semantics. 1240 * 1241 * - range.start <= range.end 1242 * - Range includes both end points [range.start..range.end] 1243 * 1244 * There is also a fallback definition provided here, allowing the 1245 * entire possible physical address range in case any platform does 1246 * not define arch_get_mappable_range(). 1247 */ 1248 struct range __weak arch_get_mappable_range(void) 1249 { 1250 struct range mhp_range = { 1251 .start = 0UL, 1252 .end = -1ULL, 1253 }; 1254 return mhp_range; 1255 } 1256 1257 struct range mhp_get_pluggable_range(bool need_mapping) 1258 { 1259 const u64 max_phys = (1ULL << MAX_PHYSMEM_BITS) - 1; 1260 struct range mhp_range; 1261 1262 if (need_mapping) { 1263 mhp_range = arch_get_mappable_range(); 1264 if (mhp_range.start > max_phys) { 1265 mhp_range.start = 0; 1266 mhp_range.end = 0; 1267 } 1268 mhp_range.end = min_t(u64, mhp_range.end, max_phys); 1269 } else { 1270 mhp_range.start = 0; 1271 mhp_range.end = max_phys; 1272 } 1273 return mhp_range; 1274 } 1275 EXPORT_SYMBOL_GPL(mhp_get_pluggable_range); 1276 1277 bool mhp_range_allowed(u64 start, u64 size, bool need_mapping) 1278 { 1279 struct range mhp_range = mhp_get_pluggable_range(need_mapping); 1280 u64 end = start + size; 1281 1282 if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end) 1283 return true; 1284 1285 pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n", 1286 start, end, mhp_range.start, mhp_range.end); 1287 return false; 1288 } 1289 1290 #ifdef CONFIG_MEMORY_HOTREMOVE 1291 /* 1292 * Confirm all pages in a range [start, end) belong to the same zone (skipping 1293 * memory holes). When true, return the zone. 1294 */ 1295 struct zone *test_pages_in_a_zone(unsigned long start_pfn, 1296 unsigned long end_pfn) 1297 { 1298 unsigned long pfn, sec_end_pfn; 1299 struct zone *zone = NULL; 1300 struct page *page; 1301 int i; 1302 for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1); 1303 pfn < end_pfn; 1304 pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) { 1305 /* Make sure the memory section is present first */ 1306 if (!present_section_nr(pfn_to_section_nr(pfn))) 1307 continue; 1308 for (; pfn < sec_end_pfn && pfn < end_pfn; 1309 pfn += MAX_ORDER_NR_PAGES) { 1310 i = 0; 1311 /* This is just a CONFIG_HOLES_IN_ZONE check.*/ 1312 while ((i < MAX_ORDER_NR_PAGES) && 1313 !pfn_valid_within(pfn + i)) 1314 i++; 1315 if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn) 1316 continue; 1317 /* Check if we got outside of the zone */ 1318 if (zone && !zone_spans_pfn(zone, pfn + i)) 1319 return NULL; 1320 page = pfn_to_page(pfn + i); 1321 if (zone && page_zone(page) != zone) 1322 return NULL; 1323 zone = page_zone(page); 1324 } 1325 } 1326 1327 return zone; 1328 } 1329 1330 /* 1331 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages, 1332 * non-lru movable pages and hugepages). Will skip over most unmovable 1333 * pages (esp., pages that can be skipped when offlining), but bail out on 1334 * definitely unmovable pages. 1335 * 1336 * Returns: 1337 * 0 in case a movable page is found and movable_pfn was updated. 1338 * -ENOENT in case no movable page was found. 1339 * -EBUSY in case a definitely unmovable page was found. 1340 */ 1341 static int scan_movable_pages(unsigned long start, unsigned long end, 1342 unsigned long *movable_pfn) 1343 { 1344 unsigned long pfn; 1345 1346 for (pfn = start; pfn < end; pfn++) { 1347 struct page *page, *head; 1348 unsigned long skip; 1349 1350 if (!pfn_valid(pfn)) 1351 continue; 1352 page = pfn_to_page(pfn); 1353 if (PageLRU(page)) 1354 goto found; 1355 if (__PageMovable(page)) 1356 goto found; 1357 1358 /* 1359 * PageOffline() pages that are not marked __PageMovable() and 1360 * have a reference count > 0 (after MEM_GOING_OFFLINE) are 1361 * definitely unmovable. If their reference count would be 0, 1362 * they could at least be skipped when offlining memory. 1363 */ 1364 if (PageOffline(page) && page_count(page)) 1365 return -EBUSY; 1366 1367 if (!PageHuge(page)) 1368 continue; 1369 head = compound_head(page); 1370 /* 1371 * This test is racy as we hold no reference or lock. The 1372 * hugetlb page could have been free'ed and head is no longer 1373 * a hugetlb page before the following check. In such unlikely 1374 * cases false positives and negatives are possible. Calling 1375 * code must deal with these scenarios. 1376 */ 1377 if (HPageMigratable(head)) 1378 goto found; 1379 skip = compound_nr(head) - (page - head); 1380 pfn += skip - 1; 1381 } 1382 return -ENOENT; 1383 found: 1384 *movable_pfn = pfn; 1385 return 0; 1386 } 1387 1388 static int 1389 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 1390 { 1391 unsigned long pfn; 1392 struct page *page, *head; 1393 int ret = 0; 1394 LIST_HEAD(source); 1395 static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL, 1396 DEFAULT_RATELIMIT_BURST); 1397 1398 for (pfn = start_pfn; pfn < end_pfn; pfn++) { 1399 if (!pfn_valid(pfn)) 1400 continue; 1401 page = pfn_to_page(pfn); 1402 head = compound_head(page); 1403 1404 if (PageHuge(page)) { 1405 pfn = page_to_pfn(head) + compound_nr(head) - 1; 1406 isolate_huge_page(head, &source); 1407 continue; 1408 } else if (PageTransHuge(page)) 1409 pfn = page_to_pfn(head) + thp_nr_pages(page) - 1; 1410 1411 /* 1412 * HWPoison pages have elevated reference counts so the migration would 1413 * fail on them. It also doesn't make any sense to migrate them in the 1414 * first place. Still try to unmap such a page in case it is still mapped 1415 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep 1416 * the unmap as the catch all safety net). 1417 */ 1418 if (PageHWPoison(page)) { 1419 if (WARN_ON(PageLRU(page))) 1420 isolate_lru_page(page); 1421 if (page_mapped(page)) 1422 try_to_unmap(page, TTU_IGNORE_MLOCK); 1423 continue; 1424 } 1425 1426 if (!get_page_unless_zero(page)) 1427 continue; 1428 /* 1429 * We can skip free pages. And we can deal with pages on 1430 * LRU and non-lru movable pages. 1431 */ 1432 if (PageLRU(page)) 1433 ret = isolate_lru_page(page); 1434 else 1435 ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE); 1436 if (!ret) { /* Success */ 1437 list_add_tail(&page->lru, &source); 1438 if (!__PageMovable(page)) 1439 inc_node_page_state(page, NR_ISOLATED_ANON + 1440 page_is_file_lru(page)); 1441 1442 } else { 1443 if (__ratelimit(&migrate_rs)) { 1444 pr_warn("failed to isolate pfn %lx\n", pfn); 1445 dump_page(page, "isolation failed"); 1446 } 1447 } 1448 put_page(page); 1449 } 1450 if (!list_empty(&source)) { 1451 nodemask_t nmask = node_states[N_MEMORY]; 1452 struct migration_target_control mtc = { 1453 .nmask = &nmask, 1454 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, 1455 }; 1456 1457 /* 1458 * We have checked that migration range is on a single zone so 1459 * we can use the nid of the first page to all the others. 1460 */ 1461 mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru)); 1462 1463 /* 1464 * try to allocate from a different node but reuse this node 1465 * if there are no other online nodes to be used (e.g. we are 1466 * offlining a part of the only existing node) 1467 */ 1468 node_clear(mtc.nid, nmask); 1469 if (nodes_empty(nmask)) 1470 node_set(mtc.nid, nmask); 1471 ret = migrate_pages(&source, alloc_migration_target, NULL, 1472 (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG); 1473 if (ret) { 1474 list_for_each_entry(page, &source, lru) { 1475 if (__ratelimit(&migrate_rs)) { 1476 pr_warn("migrating pfn %lx failed ret:%d\n", 1477 page_to_pfn(page), ret); 1478 dump_page(page, "migration failure"); 1479 } 1480 } 1481 putback_movable_pages(&source); 1482 } 1483 } 1484 1485 return ret; 1486 } 1487 1488 static int __init cmdline_parse_movable_node(char *p) 1489 { 1490 movable_node_enabled = true; 1491 return 0; 1492 } 1493 early_param("movable_node", cmdline_parse_movable_node); 1494 1495 /* check which state of node_states will be changed when offline memory */ 1496 static void node_states_check_changes_offline(unsigned long nr_pages, 1497 struct zone *zone, struct memory_notify *arg) 1498 { 1499 struct pglist_data *pgdat = zone->zone_pgdat; 1500 unsigned long present_pages = 0; 1501 enum zone_type zt; 1502 1503 arg->status_change_nid = NUMA_NO_NODE; 1504 arg->status_change_nid_normal = NUMA_NO_NODE; 1505 arg->status_change_nid_high = NUMA_NO_NODE; 1506 1507 /* 1508 * Check whether node_states[N_NORMAL_MEMORY] will be changed. 1509 * If the memory to be offline is within the range 1510 * [0..ZONE_NORMAL], and it is the last present memory there, 1511 * the zones in that range will become empty after the offlining, 1512 * thus we can determine that we need to clear the node from 1513 * node_states[N_NORMAL_MEMORY]. 1514 */ 1515 for (zt = 0; zt <= ZONE_NORMAL; zt++) 1516 present_pages += pgdat->node_zones[zt].present_pages; 1517 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages) 1518 arg->status_change_nid_normal = zone_to_nid(zone); 1519 1520 #ifdef CONFIG_HIGHMEM 1521 /* 1522 * node_states[N_HIGH_MEMORY] contains nodes which 1523 * have normal memory or high memory. 1524 * Here we add the present_pages belonging to ZONE_HIGHMEM. 1525 * If the zone is within the range of [0..ZONE_HIGHMEM), and 1526 * we determine that the zones in that range become empty, 1527 * we need to clear the node for N_HIGH_MEMORY. 1528 */ 1529 present_pages += pgdat->node_zones[ZONE_HIGHMEM].present_pages; 1530 if (zone_idx(zone) <= ZONE_HIGHMEM && nr_pages >= present_pages) 1531 arg->status_change_nid_high = zone_to_nid(zone); 1532 #endif 1533 1534 /* 1535 * We have accounted the pages from [0..ZONE_NORMAL), and 1536 * in case of CONFIG_HIGHMEM the pages from ZONE_HIGHMEM 1537 * as well. 1538 * Here we count the possible pages from ZONE_MOVABLE. 1539 * If after having accounted all the pages, we see that the nr_pages 1540 * to be offlined is over or equal to the accounted pages, 1541 * we know that the node will become empty, and so, we can clear 1542 * it for N_MEMORY as well. 1543 */ 1544 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages; 1545 1546 if (nr_pages >= present_pages) 1547 arg->status_change_nid = zone_to_nid(zone); 1548 } 1549 1550 static void node_states_clear_node(int node, struct memory_notify *arg) 1551 { 1552 if (arg->status_change_nid_normal >= 0) 1553 node_clear_state(node, N_NORMAL_MEMORY); 1554 1555 if (arg->status_change_nid_high >= 0) 1556 node_clear_state(node, N_HIGH_MEMORY); 1557 1558 if (arg->status_change_nid >= 0) 1559 node_clear_state(node, N_MEMORY); 1560 } 1561 1562 static int count_system_ram_pages_cb(unsigned long start_pfn, 1563 unsigned long nr_pages, void *data) 1564 { 1565 unsigned long *nr_system_ram_pages = data; 1566 1567 *nr_system_ram_pages += nr_pages; 1568 return 0; 1569 } 1570 1571 int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages) 1572 { 1573 const unsigned long end_pfn = start_pfn + nr_pages; 1574 unsigned long pfn, system_ram_pages = 0; 1575 unsigned long flags; 1576 struct zone *zone; 1577 struct memory_notify arg; 1578 int ret, node; 1579 char *reason; 1580 1581 /* 1582 * {on,off}lining is constrained to full memory sections (or more 1583 * precisely to memory blocks from the user space POV). 1584 * memmap_on_memory is an exception because it reserves initial part 1585 * of the physical memory space for vmemmaps. That space is pageblock 1586 * aligned. 1587 */ 1588 if (WARN_ON_ONCE(!nr_pages || 1589 !IS_ALIGNED(start_pfn, pageblock_nr_pages) || 1590 !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))) 1591 return -EINVAL; 1592 1593 mem_hotplug_begin(); 1594 1595 /* 1596 * Don't allow to offline memory blocks that contain holes. 1597 * Consequently, memory blocks with holes can never get onlined 1598 * via the hotplug path - online_pages() - as hotplugged memory has 1599 * no holes. This way, we e.g., don't have to worry about marking 1600 * memory holes PG_reserved, don't need pfn_valid() checks, and can 1601 * avoid using walk_system_ram_range() later. 1602 */ 1603 walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages, 1604 count_system_ram_pages_cb); 1605 if (system_ram_pages != nr_pages) { 1606 ret = -EINVAL; 1607 reason = "memory holes"; 1608 goto failed_removal; 1609 } 1610 1611 /* This makes hotplug much easier...and readable. 1612 we assume this for now. .*/ 1613 zone = test_pages_in_a_zone(start_pfn, end_pfn); 1614 if (!zone) { 1615 ret = -EINVAL; 1616 reason = "multizone range"; 1617 goto failed_removal; 1618 } 1619 node = zone_to_nid(zone); 1620 1621 /* 1622 * Disable pcplists so that page isolation cannot race with freeing 1623 * in a way that pages from isolated pageblock are left on pcplists. 1624 */ 1625 zone_pcp_disable(zone); 1626 lru_cache_disable(); 1627 1628 /* set above range as isolated */ 1629 ret = start_isolate_page_range(start_pfn, end_pfn, 1630 MIGRATE_MOVABLE, 1631 MEMORY_OFFLINE | REPORT_FAILURE); 1632 if (ret) { 1633 reason = "failure to isolate range"; 1634 goto failed_removal_pcplists_disabled; 1635 } 1636 1637 arg.start_pfn = start_pfn; 1638 arg.nr_pages = nr_pages; 1639 node_states_check_changes_offline(nr_pages, zone, &arg); 1640 1641 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 1642 ret = notifier_to_errno(ret); 1643 if (ret) { 1644 reason = "notifier failure"; 1645 goto failed_removal_isolated; 1646 } 1647 1648 do { 1649 pfn = start_pfn; 1650 do { 1651 if (signal_pending(current)) { 1652 ret = -EINTR; 1653 reason = "signal backoff"; 1654 goto failed_removal_isolated; 1655 } 1656 1657 cond_resched(); 1658 1659 ret = scan_movable_pages(pfn, end_pfn, &pfn); 1660 if (!ret) { 1661 /* 1662 * TODO: fatal migration failures should bail 1663 * out 1664 */ 1665 do_migrate_range(pfn, end_pfn); 1666 } 1667 } while (!ret); 1668 1669 if (ret != -ENOENT) { 1670 reason = "unmovable page"; 1671 goto failed_removal_isolated; 1672 } 1673 1674 /* 1675 * Dissolve free hugepages in the memory block before doing 1676 * offlining actually in order to make hugetlbfs's object 1677 * counting consistent. 1678 */ 1679 ret = dissolve_free_huge_pages(start_pfn, end_pfn); 1680 if (ret) { 1681 reason = "failure to dissolve huge pages"; 1682 goto failed_removal_isolated; 1683 } 1684 1685 ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE); 1686 1687 } while (ret); 1688 1689 /* Mark all sections offline and remove free pages from the buddy. */ 1690 __offline_isolated_pages(start_pfn, end_pfn); 1691 pr_debug("Offlined Pages %ld\n", nr_pages); 1692 1693 /* 1694 * The memory sections are marked offline, and the pageblock flags 1695 * effectively stale; nobody should be touching them. Fixup the number 1696 * of isolated pageblocks, memory onlining will properly revert this. 1697 */ 1698 spin_lock_irqsave(&zone->lock, flags); 1699 zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages; 1700 spin_unlock_irqrestore(&zone->lock, flags); 1701 1702 lru_cache_enable(); 1703 zone_pcp_enable(zone); 1704 1705 /* removal success */ 1706 adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages); 1707 adjust_present_page_count(zone, -nr_pages); 1708 1709 /* reinitialise watermarks and update pcp limits */ 1710 init_per_zone_wmark_min(); 1711 1712 if (!populated_zone(zone)) { 1713 zone_pcp_reset(zone); 1714 build_all_zonelists(NULL); 1715 } 1716 1717 node_states_clear_node(node, &arg); 1718 if (arg.status_change_nid >= 0) { 1719 kswapd_stop(node); 1720 kcompactd_stop(node); 1721 } 1722 1723 writeback_set_ratelimit(); 1724 1725 memory_notify(MEM_OFFLINE, &arg); 1726 remove_pfn_range_from_zone(zone, start_pfn, nr_pages); 1727 mem_hotplug_done(); 1728 return 0; 1729 1730 failed_removal_isolated: 1731 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); 1732 memory_notify(MEM_CANCEL_OFFLINE, &arg); 1733 failed_removal_pcplists_disabled: 1734 lru_cache_enable(); 1735 zone_pcp_enable(zone); 1736 failed_removal: 1737 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n", 1738 (unsigned long long) start_pfn << PAGE_SHIFT, 1739 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1, 1740 reason); 1741 /* pushback to free area */ 1742 mem_hotplug_done(); 1743 return ret; 1744 } 1745 1746 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg) 1747 { 1748 int ret = !is_memblock_offlined(mem); 1749 1750 if (unlikely(ret)) { 1751 phys_addr_t beginpa, endpa; 1752 1753 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)); 1754 endpa = beginpa + memory_block_size_bytes() - 1; 1755 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n", 1756 &beginpa, &endpa); 1757 1758 return -EBUSY; 1759 } 1760 return 0; 1761 } 1762 1763 static int get_nr_vmemmap_pages_cb(struct memory_block *mem, void *arg) 1764 { 1765 /* 1766 * If not set, continue with the next block. 1767 */ 1768 return mem->nr_vmemmap_pages; 1769 } 1770 1771 static int check_cpu_on_node(pg_data_t *pgdat) 1772 { 1773 int cpu; 1774 1775 for_each_present_cpu(cpu) { 1776 if (cpu_to_node(cpu) == pgdat->node_id) 1777 /* 1778 * the cpu on this node isn't removed, and we can't 1779 * offline this node. 1780 */ 1781 return -EBUSY; 1782 } 1783 1784 return 0; 1785 } 1786 1787 static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg) 1788 { 1789 int nid = *(int *)arg; 1790 1791 /* 1792 * If a memory block belongs to multiple nodes, the stored nid is not 1793 * reliable. However, such blocks are always online (e.g., cannot get 1794 * offlined) and, therefore, are still spanned by the node. 1795 */ 1796 return mem->nid == nid ? -EEXIST : 0; 1797 } 1798 1799 /** 1800 * try_offline_node 1801 * @nid: the node ID 1802 * 1803 * Offline a node if all memory sections and cpus of the node are removed. 1804 * 1805 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 1806 * and online/offline operations before this call. 1807 */ 1808 void try_offline_node(int nid) 1809 { 1810 pg_data_t *pgdat = NODE_DATA(nid); 1811 int rc; 1812 1813 /* 1814 * If the node still spans pages (especially ZONE_DEVICE), don't 1815 * offline it. A node spans memory after move_pfn_range_to_zone(), 1816 * e.g., after the memory block was onlined. 1817 */ 1818 if (pgdat->node_spanned_pages) 1819 return; 1820 1821 /* 1822 * Especially offline memory blocks might not be spanned by the 1823 * node. They will get spanned by the node once they get onlined. 1824 * However, they link to the node in sysfs and can get onlined later. 1825 */ 1826 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb); 1827 if (rc) 1828 return; 1829 1830 if (check_cpu_on_node(pgdat)) 1831 return; 1832 1833 /* 1834 * all memory/cpu of this node are removed, we can offline this 1835 * node now. 1836 */ 1837 node_set_offline(nid); 1838 unregister_one_node(nid); 1839 } 1840 EXPORT_SYMBOL(try_offline_node); 1841 1842 static int __ref try_remove_memory(int nid, u64 start, u64 size) 1843 { 1844 int rc = 0; 1845 struct vmem_altmap mhp_altmap = {}; 1846 struct vmem_altmap *altmap = NULL; 1847 unsigned long nr_vmemmap_pages; 1848 1849 BUG_ON(check_hotplug_memory_range(start, size)); 1850 1851 /* 1852 * All memory blocks must be offlined before removing memory. Check 1853 * whether all memory blocks in question are offline and return error 1854 * if this is not the case. 1855 */ 1856 rc = walk_memory_blocks(start, size, NULL, check_memblock_offlined_cb); 1857 if (rc) 1858 return rc; 1859 1860 /* 1861 * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in 1862 * the same granularity it was added - a single memory block. 1863 */ 1864 if (memmap_on_memory) { 1865 nr_vmemmap_pages = walk_memory_blocks(start, size, NULL, 1866 get_nr_vmemmap_pages_cb); 1867 if (nr_vmemmap_pages) { 1868 if (size != memory_block_size_bytes()) { 1869 pr_warn("Refuse to remove %#llx - %#llx," 1870 "wrong granularity\n", 1871 start, start + size); 1872 return -EINVAL; 1873 } 1874 1875 /* 1876 * Let remove_pmd_table->free_hugepage_table do the 1877 * right thing if we used vmem_altmap when hot-adding 1878 * the range. 1879 */ 1880 mhp_altmap.alloc = nr_vmemmap_pages; 1881 altmap = &mhp_altmap; 1882 } 1883 } 1884 1885 /* remove memmap entry */ 1886 firmware_map_remove(start, start + size, "System RAM"); 1887 1888 /* 1889 * Memory block device removal under the device_hotplug_lock is 1890 * a barrier against racing online attempts. 1891 */ 1892 remove_memory_block_devices(start, size); 1893 1894 mem_hotplug_begin(); 1895 1896 arch_remove_memory(nid, start, size, altmap); 1897 1898 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { 1899 memblock_free(start, size); 1900 memblock_remove(start, size); 1901 } 1902 1903 release_mem_region_adjustable(start, size); 1904 1905 try_offline_node(nid); 1906 1907 mem_hotplug_done(); 1908 return 0; 1909 } 1910 1911 /** 1912 * __remove_memory - Remove memory if every memory block is offline 1913 * @nid: the node ID 1914 * @start: physical address of the region to remove 1915 * @size: size of the region to remove 1916 * 1917 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 1918 * and online/offline operations before this call, as required by 1919 * try_offline_node(). 1920 */ 1921 void __remove_memory(int nid, u64 start, u64 size) 1922 { 1923 1924 /* 1925 * trigger BUG() if some memory is not offlined prior to calling this 1926 * function 1927 */ 1928 if (try_remove_memory(nid, start, size)) 1929 BUG(); 1930 } 1931 1932 /* 1933 * Remove memory if every memory block is offline, otherwise return -EBUSY is 1934 * some memory is not offline 1935 */ 1936 int remove_memory(int nid, u64 start, u64 size) 1937 { 1938 int rc; 1939 1940 lock_device_hotplug(); 1941 rc = try_remove_memory(nid, start, size); 1942 unlock_device_hotplug(); 1943 1944 return rc; 1945 } 1946 EXPORT_SYMBOL_GPL(remove_memory); 1947 1948 static int try_offline_memory_block(struct memory_block *mem, void *arg) 1949 { 1950 uint8_t online_type = MMOP_ONLINE_KERNEL; 1951 uint8_t **online_types = arg; 1952 struct page *page; 1953 int rc; 1954 1955 /* 1956 * Sense the online_type via the zone of the memory block. Offlining 1957 * with multiple zones within one memory block will be rejected 1958 * by offlining code ... so we don't care about that. 1959 */ 1960 page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr)); 1961 if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE) 1962 online_type = MMOP_ONLINE_MOVABLE; 1963 1964 rc = device_offline(&mem->dev); 1965 /* 1966 * Default is MMOP_OFFLINE - change it only if offlining succeeded, 1967 * so try_reonline_memory_block() can do the right thing. 1968 */ 1969 if (!rc) 1970 **online_types = online_type; 1971 1972 (*online_types)++; 1973 /* Ignore if already offline. */ 1974 return rc < 0 ? rc : 0; 1975 } 1976 1977 static int try_reonline_memory_block(struct memory_block *mem, void *arg) 1978 { 1979 uint8_t **online_types = arg; 1980 int rc; 1981 1982 if (**online_types != MMOP_OFFLINE) { 1983 mem->online_type = **online_types; 1984 rc = device_online(&mem->dev); 1985 if (rc < 0) 1986 pr_warn("%s: Failed to re-online memory: %d", 1987 __func__, rc); 1988 } 1989 1990 /* Continue processing all remaining memory blocks. */ 1991 (*online_types)++; 1992 return 0; 1993 } 1994 1995 /* 1996 * Try to offline and remove memory. Might take a long time to finish in case 1997 * memory is still in use. Primarily useful for memory devices that logically 1998 * unplugged all memory (so it's no longer in use) and want to offline + remove 1999 * that memory. 2000 */ 2001 int offline_and_remove_memory(int nid, u64 start, u64 size) 2002 { 2003 const unsigned long mb_count = size / memory_block_size_bytes(); 2004 uint8_t *online_types, *tmp; 2005 int rc; 2006 2007 if (!IS_ALIGNED(start, memory_block_size_bytes()) || 2008 !IS_ALIGNED(size, memory_block_size_bytes()) || !size) 2009 return -EINVAL; 2010 2011 /* 2012 * We'll remember the old online type of each memory block, so we can 2013 * try to revert whatever we did when offlining one memory block fails 2014 * after offlining some others succeeded. 2015 */ 2016 online_types = kmalloc_array(mb_count, sizeof(*online_types), 2017 GFP_KERNEL); 2018 if (!online_types) 2019 return -ENOMEM; 2020 /* 2021 * Initialize all states to MMOP_OFFLINE, so when we abort processing in 2022 * try_offline_memory_block(), we'll skip all unprocessed blocks in 2023 * try_reonline_memory_block(). 2024 */ 2025 memset(online_types, MMOP_OFFLINE, mb_count); 2026 2027 lock_device_hotplug(); 2028 2029 tmp = online_types; 2030 rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block); 2031 2032 /* 2033 * In case we succeeded to offline all memory, remove it. 2034 * This cannot fail as it cannot get onlined in the meantime. 2035 */ 2036 if (!rc) { 2037 rc = try_remove_memory(nid, start, size); 2038 if (rc) 2039 pr_err("%s: Failed to remove memory: %d", __func__, rc); 2040 } 2041 2042 /* 2043 * Rollback what we did. While memory onlining might theoretically fail 2044 * (nacked by a notifier), it barely ever happens. 2045 */ 2046 if (rc) { 2047 tmp = online_types; 2048 walk_memory_blocks(start, size, &tmp, 2049 try_reonline_memory_block); 2050 } 2051 unlock_device_hotplug(); 2052 2053 kfree(online_types); 2054 return rc; 2055 } 2056 EXPORT_SYMBOL_GPL(offline_and_remove_memory); 2057 #endif /* CONFIG_MEMORY_HOTREMOVE */ 2058