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/writeback.h> 17 #include <linux/slab.h> 18 #include <linux/sysctl.h> 19 #include <linux/cpu.h> 20 #include <linux/memory.h> 21 #include <linux/memremap.h> 22 #include <linux/memory_hotplug.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/compaction.h> 36 #include <linux/rmap.h> 37 #include <linux/module.h> 38 39 #include <asm/tlbflush.h> 40 41 #include "internal.h" 42 #include "shuffle.h" 43 44 #ifdef CONFIG_MHP_MEMMAP_ON_MEMORY 45 /* 46 * memory_hotplug.memmap_on_memory parameter 47 */ 48 static bool memmap_on_memory __ro_after_init; 49 module_param(memmap_on_memory, bool, 0444); 50 MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug"); 51 52 static inline bool mhp_memmap_on_memory(void) 53 { 54 return memmap_on_memory; 55 } 56 #else 57 static inline bool mhp_memmap_on_memory(void) 58 { 59 return false; 60 } 61 #endif 62 63 enum { 64 ONLINE_POLICY_CONTIG_ZONES = 0, 65 ONLINE_POLICY_AUTO_MOVABLE, 66 }; 67 68 static const char * const online_policy_to_str[] = { 69 [ONLINE_POLICY_CONTIG_ZONES] = "contig-zones", 70 [ONLINE_POLICY_AUTO_MOVABLE] = "auto-movable", 71 }; 72 73 static int set_online_policy(const char *val, const struct kernel_param *kp) 74 { 75 int ret = sysfs_match_string(online_policy_to_str, val); 76 77 if (ret < 0) 78 return ret; 79 *((int *)kp->arg) = ret; 80 return 0; 81 } 82 83 static int get_online_policy(char *buffer, const struct kernel_param *kp) 84 { 85 return sprintf(buffer, "%s\n", online_policy_to_str[*((int *)kp->arg)]); 86 } 87 88 /* 89 * memory_hotplug.online_policy: configure online behavior when onlining without 90 * specifying a zone (MMOP_ONLINE) 91 * 92 * "contig-zones": keep zone contiguous 93 * "auto-movable": online memory to ZONE_MOVABLE if the configuration 94 * (auto_movable_ratio, auto_movable_numa_aware) allows for it 95 */ 96 static int online_policy __read_mostly = ONLINE_POLICY_CONTIG_ZONES; 97 static const struct kernel_param_ops online_policy_ops = { 98 .set = set_online_policy, 99 .get = get_online_policy, 100 }; 101 module_param_cb(online_policy, &online_policy_ops, &online_policy, 0644); 102 MODULE_PARM_DESC(online_policy, 103 "Set the online policy (\"contig-zones\", \"auto-movable\") " 104 "Default: \"contig-zones\""); 105 106 /* 107 * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio 108 * 109 * The ratio represent an upper limit and the kernel might decide to not 110 * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory 111 * doesn't allow for more MOVABLE memory. 112 */ 113 static unsigned int auto_movable_ratio __read_mostly = 301; 114 module_param(auto_movable_ratio, uint, 0644); 115 MODULE_PARM_DESC(auto_movable_ratio, 116 "Set the maximum ratio of MOVABLE:KERNEL memory in the system " 117 "in percent for \"auto-movable\" online policy. Default: 301"); 118 119 /* 120 * memory_hotplug.auto_movable_numa_aware: consider numa node stats 121 */ 122 #ifdef CONFIG_NUMA 123 static bool auto_movable_numa_aware __read_mostly = true; 124 module_param(auto_movable_numa_aware, bool, 0644); 125 MODULE_PARM_DESC(auto_movable_numa_aware, 126 "Consider numa node stats in addition to global stats in " 127 "\"auto-movable\" online policy. Default: true"); 128 #endif /* CONFIG_NUMA */ 129 130 /* 131 * online_page_callback contains pointer to current page onlining function. 132 * Initially it is generic_online_page(). If it is required it could be 133 * changed by calling set_online_page_callback() for callback registration 134 * and restore_online_page_callback() for generic callback restore. 135 */ 136 137 static online_page_callback_t online_page_callback = generic_online_page; 138 static DEFINE_MUTEX(online_page_callback_lock); 139 140 DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock); 141 142 void get_online_mems(void) 143 { 144 percpu_down_read(&mem_hotplug_lock); 145 } 146 147 void put_online_mems(void) 148 { 149 percpu_up_read(&mem_hotplug_lock); 150 } 151 152 bool movable_node_enabled = false; 153 154 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE 155 int mhp_default_online_type = MMOP_OFFLINE; 156 #else 157 int mhp_default_online_type = MMOP_ONLINE; 158 #endif 159 160 static int __init setup_memhp_default_state(char *str) 161 { 162 const int online_type = mhp_online_type_from_str(str); 163 164 if (online_type >= 0) 165 mhp_default_online_type = online_type; 166 167 return 1; 168 } 169 __setup("memhp_default_state=", setup_memhp_default_state); 170 171 void mem_hotplug_begin(void) 172 { 173 cpus_read_lock(); 174 percpu_down_write(&mem_hotplug_lock); 175 } 176 177 void mem_hotplug_done(void) 178 { 179 percpu_up_write(&mem_hotplug_lock); 180 cpus_read_unlock(); 181 } 182 183 u64 max_mem_size = U64_MAX; 184 185 /* add this memory to iomem resource */ 186 static struct resource *register_memory_resource(u64 start, u64 size, 187 const char *resource_name) 188 { 189 struct resource *res; 190 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; 191 192 if (strcmp(resource_name, "System RAM")) 193 flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED; 194 195 if (!mhp_range_allowed(start, size, true)) 196 return ERR_PTR(-E2BIG); 197 198 /* 199 * Make sure value parsed from 'mem=' only restricts memory adding 200 * while booting, so that memory hotplug won't be impacted. Please 201 * refer to document of 'mem=' in kernel-parameters.txt for more 202 * details. 203 */ 204 if (start + size > max_mem_size && system_state < SYSTEM_RUNNING) 205 return ERR_PTR(-E2BIG); 206 207 /* 208 * Request ownership of the new memory range. This might be 209 * a child of an existing resource that was present but 210 * not marked as busy. 211 */ 212 res = __request_region(&iomem_resource, start, size, 213 resource_name, flags); 214 215 if (!res) { 216 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n", 217 start, start + size); 218 return ERR_PTR(-EEXIST); 219 } 220 return res; 221 } 222 223 static void release_memory_resource(struct resource *res) 224 { 225 if (!res) 226 return; 227 release_resource(res); 228 kfree(res); 229 } 230 231 static int check_pfn_span(unsigned long pfn, unsigned long nr_pages) 232 { 233 /* 234 * Disallow all operations smaller than a sub-section and only 235 * allow operations smaller than a section for 236 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range() 237 * enforces a larger memory_block_size_bytes() granularity for 238 * memory that will be marked online, so this check should only 239 * fire for direct arch_{add,remove}_memory() users outside of 240 * add_memory_resource(). 241 */ 242 unsigned long min_align; 243 244 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) 245 min_align = PAGES_PER_SUBSECTION; 246 else 247 min_align = PAGES_PER_SECTION; 248 if (!IS_ALIGNED(pfn | nr_pages, min_align)) 249 return -EINVAL; 250 return 0; 251 } 252 253 /* 254 * Return page for the valid pfn only if the page is online. All pfn 255 * walkers which rely on the fully initialized page->flags and others 256 * should use this rather than pfn_valid && pfn_to_page 257 */ 258 struct page *pfn_to_online_page(unsigned long pfn) 259 { 260 unsigned long nr = pfn_to_section_nr(pfn); 261 struct dev_pagemap *pgmap; 262 struct mem_section *ms; 263 264 if (nr >= NR_MEM_SECTIONS) 265 return NULL; 266 267 ms = __nr_to_section(nr); 268 if (!online_section(ms)) 269 return NULL; 270 271 /* 272 * Save some code text when online_section() + 273 * pfn_section_valid() are sufficient. 274 */ 275 if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn)) 276 return NULL; 277 278 if (!pfn_section_valid(ms, pfn)) 279 return NULL; 280 281 if (!online_device_section(ms)) 282 return pfn_to_page(pfn); 283 284 /* 285 * Slowpath: when ZONE_DEVICE collides with 286 * ZONE_{NORMAL,MOVABLE} within the same section some pfns in 287 * the section may be 'offline' but 'valid'. Only 288 * get_dev_pagemap() can determine sub-section online status. 289 */ 290 pgmap = get_dev_pagemap(pfn, NULL); 291 put_dev_pagemap(pgmap); 292 293 /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */ 294 if (pgmap) 295 return NULL; 296 297 return pfn_to_page(pfn); 298 } 299 EXPORT_SYMBOL_GPL(pfn_to_online_page); 300 301 int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages, 302 struct mhp_params *params) 303 { 304 const unsigned long end_pfn = pfn + nr_pages; 305 unsigned long cur_nr_pages; 306 int err; 307 struct vmem_altmap *altmap = params->altmap; 308 309 if (WARN_ON_ONCE(!pgprot_val(params->pgprot))) 310 return -EINVAL; 311 312 VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false)); 313 314 if (altmap) { 315 /* 316 * Validate altmap is within bounds of the total request 317 */ 318 if (altmap->base_pfn != pfn 319 || vmem_altmap_offset(altmap) > nr_pages) { 320 pr_warn_once("memory add fail, invalid altmap\n"); 321 return -EINVAL; 322 } 323 altmap->alloc = 0; 324 } 325 326 if (check_pfn_span(pfn, nr_pages)) { 327 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1); 328 return -EINVAL; 329 } 330 331 for (; pfn < end_pfn; pfn += cur_nr_pages) { 332 /* Select all remaining pages up to the next section boundary */ 333 cur_nr_pages = min(end_pfn - pfn, 334 SECTION_ALIGN_UP(pfn + 1) - pfn); 335 err = sparse_add_section(nid, pfn, cur_nr_pages, altmap, 336 params->pgmap); 337 if (err) 338 break; 339 cond_resched(); 340 } 341 vmemmap_populate_print_last(); 342 return err; 343 } 344 345 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */ 346 static unsigned long find_smallest_section_pfn(int nid, struct zone *zone, 347 unsigned long start_pfn, 348 unsigned long end_pfn) 349 { 350 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) { 351 if (unlikely(!pfn_to_online_page(start_pfn))) 352 continue; 353 354 if (unlikely(pfn_to_nid(start_pfn) != nid)) 355 continue; 356 357 if (zone != page_zone(pfn_to_page(start_pfn))) 358 continue; 359 360 return start_pfn; 361 } 362 363 return 0; 364 } 365 366 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */ 367 static unsigned long find_biggest_section_pfn(int nid, struct zone *zone, 368 unsigned long start_pfn, 369 unsigned long end_pfn) 370 { 371 unsigned long pfn; 372 373 /* pfn is the end pfn of a memory section. */ 374 pfn = end_pfn - 1; 375 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) { 376 if (unlikely(!pfn_to_online_page(pfn))) 377 continue; 378 379 if (unlikely(pfn_to_nid(pfn) != nid)) 380 continue; 381 382 if (zone != page_zone(pfn_to_page(pfn))) 383 continue; 384 385 return pfn; 386 } 387 388 return 0; 389 } 390 391 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, 392 unsigned long end_pfn) 393 { 394 unsigned long pfn; 395 int nid = zone_to_nid(zone); 396 397 if (zone->zone_start_pfn == start_pfn) { 398 /* 399 * If the section is smallest section in the zone, it need 400 * shrink zone->zone_start_pfn and zone->zone_spanned_pages. 401 * In this case, we find second smallest valid mem_section 402 * for shrinking zone. 403 */ 404 pfn = find_smallest_section_pfn(nid, zone, end_pfn, 405 zone_end_pfn(zone)); 406 if (pfn) { 407 zone->spanned_pages = zone_end_pfn(zone) - pfn; 408 zone->zone_start_pfn = pfn; 409 } else { 410 zone->zone_start_pfn = 0; 411 zone->spanned_pages = 0; 412 } 413 } else if (zone_end_pfn(zone) == end_pfn) { 414 /* 415 * If the section is biggest section in the zone, it need 416 * shrink zone->spanned_pages. 417 * In this case, we find second biggest valid mem_section for 418 * shrinking zone. 419 */ 420 pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn, 421 start_pfn); 422 if (pfn) 423 zone->spanned_pages = pfn - zone->zone_start_pfn + 1; 424 else { 425 zone->zone_start_pfn = 0; 426 zone->spanned_pages = 0; 427 } 428 } 429 } 430 431 static void update_pgdat_span(struct pglist_data *pgdat) 432 { 433 unsigned long node_start_pfn = 0, node_end_pfn = 0; 434 struct zone *zone; 435 436 for (zone = pgdat->node_zones; 437 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) { 438 unsigned long end_pfn = zone_end_pfn(zone); 439 440 /* No need to lock the zones, they can't change. */ 441 if (!zone->spanned_pages) 442 continue; 443 if (!node_end_pfn) { 444 node_start_pfn = zone->zone_start_pfn; 445 node_end_pfn = end_pfn; 446 continue; 447 } 448 449 if (end_pfn > node_end_pfn) 450 node_end_pfn = end_pfn; 451 if (zone->zone_start_pfn < node_start_pfn) 452 node_start_pfn = zone->zone_start_pfn; 453 } 454 455 pgdat->node_start_pfn = node_start_pfn; 456 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn; 457 } 458 459 void __ref remove_pfn_range_from_zone(struct zone *zone, 460 unsigned long start_pfn, 461 unsigned long nr_pages) 462 { 463 const unsigned long end_pfn = start_pfn + nr_pages; 464 struct pglist_data *pgdat = zone->zone_pgdat; 465 unsigned long pfn, cur_nr_pages; 466 467 /* Poison struct pages because they are now uninitialized again. */ 468 for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) { 469 cond_resched(); 470 471 /* Select all remaining pages up to the next section boundary */ 472 cur_nr_pages = 473 min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn); 474 page_init_poison(pfn_to_page(pfn), 475 sizeof(struct page) * cur_nr_pages); 476 } 477 478 /* 479 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So 480 * we will not try to shrink the zones - which is okay as 481 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way. 482 */ 483 if (zone_is_zone_device(zone)) 484 return; 485 486 clear_zone_contiguous(zone); 487 488 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages); 489 update_pgdat_span(pgdat); 490 491 set_zone_contiguous(zone); 492 } 493 494 /** 495 * __remove_pages() - remove sections of pages 496 * @pfn: starting pageframe (must be aligned to start of a section) 497 * @nr_pages: number of pages to remove (must be multiple of section size) 498 * @altmap: alternative device page map or %NULL if default memmap is used 499 * 500 * Generic helper function to remove section mappings and sysfs entries 501 * for the section of the memory we are removing. Caller needs to make 502 * sure that pages are marked reserved and zones are adjust properly by 503 * calling offline_pages(). 504 */ 505 void __remove_pages(unsigned long pfn, unsigned long nr_pages, 506 struct vmem_altmap *altmap) 507 { 508 const unsigned long end_pfn = pfn + nr_pages; 509 unsigned long cur_nr_pages; 510 511 if (check_pfn_span(pfn, nr_pages)) { 512 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1); 513 return; 514 } 515 516 for (; pfn < end_pfn; pfn += cur_nr_pages) { 517 cond_resched(); 518 /* Select all remaining pages up to the next section boundary */ 519 cur_nr_pages = min(end_pfn - pfn, 520 SECTION_ALIGN_UP(pfn + 1) - pfn); 521 sparse_remove_section(pfn, cur_nr_pages, altmap); 522 } 523 } 524 525 int set_online_page_callback(online_page_callback_t callback) 526 { 527 int rc = -EINVAL; 528 529 get_online_mems(); 530 mutex_lock(&online_page_callback_lock); 531 532 if (online_page_callback == generic_online_page) { 533 online_page_callback = callback; 534 rc = 0; 535 } 536 537 mutex_unlock(&online_page_callback_lock); 538 put_online_mems(); 539 540 return rc; 541 } 542 EXPORT_SYMBOL_GPL(set_online_page_callback); 543 544 int restore_online_page_callback(online_page_callback_t callback) 545 { 546 int rc = -EINVAL; 547 548 get_online_mems(); 549 mutex_lock(&online_page_callback_lock); 550 551 if (online_page_callback == callback) { 552 online_page_callback = generic_online_page; 553 rc = 0; 554 } 555 556 mutex_unlock(&online_page_callback_lock); 557 put_online_mems(); 558 559 return rc; 560 } 561 EXPORT_SYMBOL_GPL(restore_online_page_callback); 562 563 void generic_online_page(struct page *page, unsigned int order) 564 { 565 /* 566 * Freeing the page with debug_pagealloc enabled will try to unmap it, 567 * so we should map it first. This is better than introducing a special 568 * case in page freeing fast path. 569 */ 570 debug_pagealloc_map_pages(page, 1 << order); 571 __free_pages_core(page, order); 572 totalram_pages_add(1UL << order); 573 } 574 EXPORT_SYMBOL_GPL(generic_online_page); 575 576 static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages) 577 { 578 const unsigned long end_pfn = start_pfn + nr_pages; 579 unsigned long pfn; 580 581 /* 582 * Online the pages in MAX_ORDER aligned chunks. The callback might 583 * decide to not expose all pages to the buddy (e.g., expose them 584 * later). We account all pages as being online and belonging to this 585 * zone ("present"). 586 * When using memmap_on_memory, the range might not be aligned to 587 * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect 588 * this and the first chunk to online will be pageblock_nr_pages. 589 */ 590 for (pfn = start_pfn; pfn < end_pfn;) { 591 int order; 592 593 /* 594 * Free to online pages in the largest chunks alignment allows. 595 * 596 * __ffs() behaviour is undefined for 0. start == 0 is 597 * MAX_ORDER-aligned, Set order to MAX_ORDER for the case. 598 */ 599 if (pfn) 600 order = min_t(int, MAX_ORDER, __ffs(pfn)); 601 else 602 order = MAX_ORDER; 603 604 (*online_page_callback)(pfn_to_page(pfn), order); 605 pfn += (1UL << order); 606 } 607 608 /* mark all involved sections as online */ 609 online_mem_sections(start_pfn, end_pfn); 610 } 611 612 /* check which state of node_states will be changed when online memory */ 613 static void node_states_check_changes_online(unsigned long nr_pages, 614 struct zone *zone, struct memory_notify *arg) 615 { 616 int nid = zone_to_nid(zone); 617 618 arg->status_change_nid = NUMA_NO_NODE; 619 arg->status_change_nid_normal = NUMA_NO_NODE; 620 621 if (!node_state(nid, N_MEMORY)) 622 arg->status_change_nid = nid; 623 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY)) 624 arg->status_change_nid_normal = nid; 625 } 626 627 static void node_states_set_node(int node, struct memory_notify *arg) 628 { 629 if (arg->status_change_nid_normal >= 0) 630 node_set_state(node, N_NORMAL_MEMORY); 631 632 if (arg->status_change_nid >= 0) 633 node_set_state(node, N_MEMORY); 634 } 635 636 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn, 637 unsigned long nr_pages) 638 { 639 unsigned long old_end_pfn = zone_end_pfn(zone); 640 641 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn) 642 zone->zone_start_pfn = start_pfn; 643 644 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn; 645 } 646 647 static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn, 648 unsigned long nr_pages) 649 { 650 unsigned long old_end_pfn = pgdat_end_pfn(pgdat); 651 652 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn) 653 pgdat->node_start_pfn = start_pfn; 654 655 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn; 656 657 } 658 659 #ifdef CONFIG_ZONE_DEVICE 660 static void section_taint_zone_device(unsigned long pfn) 661 { 662 struct mem_section *ms = __pfn_to_section(pfn); 663 664 ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE; 665 } 666 #else 667 static inline void section_taint_zone_device(unsigned long pfn) 668 { 669 } 670 #endif 671 672 /* 673 * Associate the pfn range with the given zone, initializing the memmaps 674 * and resizing the pgdat/zone data to span the added pages. After this 675 * call, all affected pages are PG_reserved. 676 * 677 * All aligned pageblocks are initialized to the specified migratetype 678 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related 679 * zone stats (e.g., nr_isolate_pageblock) are touched. 680 */ 681 void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, 682 unsigned long nr_pages, 683 struct vmem_altmap *altmap, int migratetype) 684 { 685 struct pglist_data *pgdat = zone->zone_pgdat; 686 int nid = pgdat->node_id; 687 688 clear_zone_contiguous(zone); 689 690 if (zone_is_empty(zone)) 691 init_currently_empty_zone(zone, start_pfn, nr_pages); 692 resize_zone_range(zone, start_pfn, nr_pages); 693 resize_pgdat_range(pgdat, start_pfn, nr_pages); 694 695 /* 696 * Subsection population requires care in pfn_to_online_page(). 697 * Set the taint to enable the slow path detection of 698 * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE} 699 * section. 700 */ 701 if (zone_is_zone_device(zone)) { 702 if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION)) 703 section_taint_zone_device(start_pfn); 704 if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)) 705 section_taint_zone_device(start_pfn + nr_pages); 706 } 707 708 /* 709 * TODO now we have a visible range of pages which are not associated 710 * with their zone properly. Not nice but set_pfnblock_flags_mask 711 * expects the zone spans the pfn range. All the pages in the range 712 * are reserved so nobody should be touching them so we should be safe 713 */ 714 memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0, 715 MEMINIT_HOTPLUG, altmap, migratetype); 716 717 set_zone_contiguous(zone); 718 } 719 720 struct auto_movable_stats { 721 unsigned long kernel_early_pages; 722 unsigned long movable_pages; 723 }; 724 725 static void auto_movable_stats_account_zone(struct auto_movable_stats *stats, 726 struct zone *zone) 727 { 728 if (zone_idx(zone) == ZONE_MOVABLE) { 729 stats->movable_pages += zone->present_pages; 730 } else { 731 stats->kernel_early_pages += zone->present_early_pages; 732 #ifdef CONFIG_CMA 733 /* 734 * CMA pages (never on hotplugged memory) behave like 735 * ZONE_MOVABLE. 736 */ 737 stats->movable_pages += zone->cma_pages; 738 stats->kernel_early_pages -= zone->cma_pages; 739 #endif /* CONFIG_CMA */ 740 } 741 } 742 struct auto_movable_group_stats { 743 unsigned long movable_pages; 744 unsigned long req_kernel_early_pages; 745 }; 746 747 static int auto_movable_stats_account_group(struct memory_group *group, 748 void *arg) 749 { 750 const int ratio = READ_ONCE(auto_movable_ratio); 751 struct auto_movable_group_stats *stats = arg; 752 long pages; 753 754 /* 755 * We don't support modifying the config while the auto-movable online 756 * policy is already enabled. Just avoid the division by zero below. 757 */ 758 if (!ratio) 759 return 0; 760 761 /* 762 * Calculate how many early kernel pages this group requires to 763 * satisfy the configured zone ratio. 764 */ 765 pages = group->present_movable_pages * 100 / ratio; 766 pages -= group->present_kernel_pages; 767 768 if (pages > 0) 769 stats->req_kernel_early_pages += pages; 770 stats->movable_pages += group->present_movable_pages; 771 return 0; 772 } 773 774 static bool auto_movable_can_online_movable(int nid, struct memory_group *group, 775 unsigned long nr_pages) 776 { 777 unsigned long kernel_early_pages, movable_pages; 778 struct auto_movable_group_stats group_stats = {}; 779 struct auto_movable_stats stats = {}; 780 pg_data_t *pgdat = NODE_DATA(nid); 781 struct zone *zone; 782 int i; 783 784 /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */ 785 if (nid == NUMA_NO_NODE) { 786 /* TODO: cache values */ 787 for_each_populated_zone(zone) 788 auto_movable_stats_account_zone(&stats, zone); 789 } else { 790 for (i = 0; i < MAX_NR_ZONES; i++) { 791 zone = pgdat->node_zones + i; 792 if (populated_zone(zone)) 793 auto_movable_stats_account_zone(&stats, zone); 794 } 795 } 796 797 kernel_early_pages = stats.kernel_early_pages; 798 movable_pages = stats.movable_pages; 799 800 /* 801 * Kernel memory inside dynamic memory group allows for more MOVABLE 802 * memory within the same group. Remove the effect of all but the 803 * current group from the stats. 804 */ 805 walk_dynamic_memory_groups(nid, auto_movable_stats_account_group, 806 group, &group_stats); 807 if (kernel_early_pages <= group_stats.req_kernel_early_pages) 808 return false; 809 kernel_early_pages -= group_stats.req_kernel_early_pages; 810 movable_pages -= group_stats.movable_pages; 811 812 if (group && group->is_dynamic) 813 kernel_early_pages += group->present_kernel_pages; 814 815 /* 816 * Test if we could online the given number of pages to ZONE_MOVABLE 817 * and still stay in the configured ratio. 818 */ 819 movable_pages += nr_pages; 820 return movable_pages <= (auto_movable_ratio * kernel_early_pages) / 100; 821 } 822 823 /* 824 * Returns a default kernel memory zone for the given pfn range. 825 * If no kernel zone covers this pfn range it will automatically go 826 * to the ZONE_NORMAL. 827 */ 828 static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn, 829 unsigned long nr_pages) 830 { 831 struct pglist_data *pgdat = NODE_DATA(nid); 832 int zid; 833 834 for (zid = 0; zid < ZONE_NORMAL; zid++) { 835 struct zone *zone = &pgdat->node_zones[zid]; 836 837 if (zone_intersects(zone, start_pfn, nr_pages)) 838 return zone; 839 } 840 841 return &pgdat->node_zones[ZONE_NORMAL]; 842 } 843 844 /* 845 * Determine to which zone to online memory dynamically based on user 846 * configuration and system stats. We care about the following ratio: 847 * 848 * MOVABLE : KERNEL 849 * 850 * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in 851 * one of the kernel zones. CMA pages inside one of the kernel zones really 852 * behaves like ZONE_MOVABLE, so we treat them accordingly. 853 * 854 * We don't allow for hotplugged memory in a KERNEL zone to increase the 855 * amount of MOVABLE memory we can have, so we end up with: 856 * 857 * MOVABLE : KERNEL_EARLY 858 * 859 * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze 860 * boot. We base our calculation on KERNEL_EARLY internally, because: 861 * 862 * a) Hotplugged memory in one of the kernel zones can sometimes still get 863 * hotunplugged, especially when hot(un)plugging individual memory blocks. 864 * There is no coordination across memory devices, therefore "automatic" 865 * hotunplugging, as implemented in hypervisors, could result in zone 866 * imbalances. 867 * b) Early/boot memory in one of the kernel zones can usually not get 868 * hotunplugged again (e.g., no firmware interface to unplug, fragmented 869 * with unmovable allocations). While there are corner cases where it might 870 * still work, it is barely relevant in practice. 871 * 872 * Exceptions are dynamic memory groups, which allow for more MOVABLE 873 * memory within the same memory group -- because in that case, there is 874 * coordination within the single memory device managed by a single driver. 875 * 876 * We rely on "present pages" instead of "managed pages", as the latter is 877 * highly unreliable and dynamic in virtualized environments, and does not 878 * consider boot time allocations. For example, memory ballooning adjusts the 879 * managed pages when inflating/deflating the balloon, and balloon compaction 880 * can even migrate inflated pages between zones. 881 * 882 * Using "present pages" is better but some things to keep in mind are: 883 * 884 * a) Some memblock allocations, such as for the crashkernel area, are 885 * effectively unused by the kernel, yet they account to "present pages". 886 * Fortunately, these allocations are comparatively small in relevant setups 887 * (e.g., fraction of system memory). 888 * b) Some hotplugged memory blocks in virtualized environments, esecially 889 * hotplugged by virtio-mem, look like they are completely present, however, 890 * only parts of the memory block are actually currently usable. 891 * "present pages" is an upper limit that can get reached at runtime. As 892 * we base our calculations on KERNEL_EARLY, this is not an issue. 893 */ 894 static struct zone *auto_movable_zone_for_pfn(int nid, 895 struct memory_group *group, 896 unsigned long pfn, 897 unsigned long nr_pages) 898 { 899 unsigned long online_pages = 0, max_pages, end_pfn; 900 struct page *page; 901 902 if (!auto_movable_ratio) 903 goto kernel_zone; 904 905 if (group && !group->is_dynamic) { 906 max_pages = group->s.max_pages; 907 online_pages = group->present_movable_pages; 908 909 /* If anything is !MOVABLE online the rest !MOVABLE. */ 910 if (group->present_kernel_pages) 911 goto kernel_zone; 912 } else if (!group || group->d.unit_pages == nr_pages) { 913 max_pages = nr_pages; 914 } else { 915 max_pages = group->d.unit_pages; 916 /* 917 * Take a look at all online sections in the current unit. 918 * We can safely assume that all pages within a section belong 919 * to the same zone, because dynamic memory groups only deal 920 * with hotplugged memory. 921 */ 922 pfn = ALIGN_DOWN(pfn, group->d.unit_pages); 923 end_pfn = pfn + group->d.unit_pages; 924 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 925 page = pfn_to_online_page(pfn); 926 if (!page) 927 continue; 928 /* If anything is !MOVABLE online the rest !MOVABLE. */ 929 if (!is_zone_movable_page(page)) 930 goto kernel_zone; 931 online_pages += PAGES_PER_SECTION; 932 } 933 } 934 935 /* 936 * Online MOVABLE if we could *currently* online all remaining parts 937 * MOVABLE. We expect to (add+) online them immediately next, so if 938 * nobody interferes, all will be MOVABLE if possible. 939 */ 940 nr_pages = max_pages - online_pages; 941 if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages)) 942 goto kernel_zone; 943 944 #ifdef CONFIG_NUMA 945 if (auto_movable_numa_aware && 946 !auto_movable_can_online_movable(nid, group, nr_pages)) 947 goto kernel_zone; 948 #endif /* CONFIG_NUMA */ 949 950 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 951 kernel_zone: 952 return default_kernel_zone_for_pfn(nid, pfn, nr_pages); 953 } 954 955 static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn, 956 unsigned long nr_pages) 957 { 958 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn, 959 nr_pages); 960 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 961 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages); 962 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages); 963 964 /* 965 * We inherit the existing zone in a simple case where zones do not 966 * overlap in the given range 967 */ 968 if (in_kernel ^ in_movable) 969 return (in_kernel) ? kernel_zone : movable_zone; 970 971 /* 972 * If the range doesn't belong to any zone or two zones overlap in the 973 * given range then we use movable zone only if movable_node is 974 * enabled because we always online to a kernel zone by default. 975 */ 976 return movable_node_enabled ? movable_zone : kernel_zone; 977 } 978 979 struct zone *zone_for_pfn_range(int online_type, int nid, 980 struct memory_group *group, unsigned long start_pfn, 981 unsigned long nr_pages) 982 { 983 if (online_type == MMOP_ONLINE_KERNEL) 984 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages); 985 986 if (online_type == MMOP_ONLINE_MOVABLE) 987 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 988 989 if (online_policy == ONLINE_POLICY_AUTO_MOVABLE) 990 return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages); 991 992 return default_zone_for_pfn(nid, start_pfn, nr_pages); 993 } 994 995 /* 996 * This function should only be called by memory_block_{online,offline}, 997 * and {online,offline}_pages. 998 */ 999 void adjust_present_page_count(struct page *page, struct memory_group *group, 1000 long nr_pages) 1001 { 1002 struct zone *zone = page_zone(page); 1003 const bool movable = zone_idx(zone) == ZONE_MOVABLE; 1004 1005 /* 1006 * We only support onlining/offlining/adding/removing of complete 1007 * memory blocks; therefore, either all is either early or hotplugged. 1008 */ 1009 if (early_section(__pfn_to_section(page_to_pfn(page)))) 1010 zone->present_early_pages += nr_pages; 1011 zone->present_pages += nr_pages; 1012 zone->zone_pgdat->node_present_pages += nr_pages; 1013 1014 if (group && movable) 1015 group->present_movable_pages += nr_pages; 1016 else if (group && !movable) 1017 group->present_kernel_pages += nr_pages; 1018 } 1019 1020 int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages, 1021 struct zone *zone) 1022 { 1023 unsigned long end_pfn = pfn + nr_pages; 1024 int ret, i; 1025 1026 ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); 1027 if (ret) 1028 return ret; 1029 1030 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE); 1031 1032 for (i = 0; i < nr_pages; i++) 1033 SetPageVmemmapSelfHosted(pfn_to_page(pfn + i)); 1034 1035 /* 1036 * It might be that the vmemmap_pages fully span sections. If that is 1037 * the case, mark those sections online here as otherwise they will be 1038 * left offline. 1039 */ 1040 if (nr_pages >= PAGES_PER_SECTION) 1041 online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION)); 1042 1043 return ret; 1044 } 1045 1046 void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages) 1047 { 1048 unsigned long end_pfn = pfn + nr_pages; 1049 1050 /* 1051 * It might be that the vmemmap_pages fully span sections. If that is 1052 * the case, mark those sections offline here as otherwise they will be 1053 * left online. 1054 */ 1055 if (nr_pages >= PAGES_PER_SECTION) 1056 offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION)); 1057 1058 /* 1059 * The pages associated with this vmemmap have been offlined, so 1060 * we can reset its state here. 1061 */ 1062 remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages); 1063 kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); 1064 } 1065 1066 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, 1067 struct zone *zone, struct memory_group *group) 1068 { 1069 unsigned long flags; 1070 int need_zonelists_rebuild = 0; 1071 const int nid = zone_to_nid(zone); 1072 int ret; 1073 struct memory_notify arg; 1074 1075 /* 1076 * {on,off}lining is constrained to full memory sections (or more 1077 * precisely to memory blocks from the user space POV). 1078 * memmap_on_memory is an exception because it reserves initial part 1079 * of the physical memory space for vmemmaps. That space is pageblock 1080 * aligned. 1081 */ 1082 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) || 1083 !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION))) 1084 return -EINVAL; 1085 1086 mem_hotplug_begin(); 1087 1088 /* associate pfn range with the zone */ 1089 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE); 1090 1091 arg.start_pfn = pfn; 1092 arg.nr_pages = nr_pages; 1093 node_states_check_changes_online(nr_pages, zone, &arg); 1094 1095 ret = memory_notify(MEM_GOING_ONLINE, &arg); 1096 ret = notifier_to_errno(ret); 1097 if (ret) 1098 goto failed_addition; 1099 1100 /* 1101 * Fixup the number of isolated pageblocks before marking the sections 1102 * onlining, such that undo_isolate_page_range() works correctly. 1103 */ 1104 spin_lock_irqsave(&zone->lock, flags); 1105 zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages; 1106 spin_unlock_irqrestore(&zone->lock, flags); 1107 1108 /* 1109 * If this zone is not populated, then it is not in zonelist. 1110 * This means the page allocator ignores this zone. 1111 * So, zonelist must be updated after online. 1112 */ 1113 if (!populated_zone(zone)) { 1114 need_zonelists_rebuild = 1; 1115 setup_zone_pageset(zone); 1116 } 1117 1118 online_pages_range(pfn, nr_pages); 1119 adjust_present_page_count(pfn_to_page(pfn), group, nr_pages); 1120 1121 node_states_set_node(nid, &arg); 1122 if (need_zonelists_rebuild) 1123 build_all_zonelists(NULL); 1124 1125 /* Basic onlining is complete, allow allocation of onlined pages. */ 1126 undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE); 1127 1128 /* 1129 * Freshly onlined pages aren't shuffled (e.g., all pages are placed to 1130 * the tail of the freelist when undoing isolation). Shuffle the whole 1131 * zone to make sure the just onlined pages are properly distributed 1132 * across the whole freelist - to create an initial shuffle. 1133 */ 1134 shuffle_zone(zone); 1135 1136 /* reinitialise watermarks and update pcp limits */ 1137 init_per_zone_wmark_min(); 1138 1139 kswapd_run(nid); 1140 kcompactd_run(nid); 1141 1142 writeback_set_ratelimit(); 1143 1144 memory_notify(MEM_ONLINE, &arg); 1145 mem_hotplug_done(); 1146 return 0; 1147 1148 failed_addition: 1149 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n", 1150 (unsigned long long) pfn << PAGE_SHIFT, 1151 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1); 1152 memory_notify(MEM_CANCEL_ONLINE, &arg); 1153 remove_pfn_range_from_zone(zone, pfn, nr_pages); 1154 mem_hotplug_done(); 1155 return ret; 1156 } 1157 1158 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 1159 static pg_data_t __ref *hotadd_init_pgdat(int nid) 1160 { 1161 struct pglist_data *pgdat; 1162 1163 /* 1164 * NODE_DATA is preallocated (free_area_init) but its internal 1165 * state is not allocated completely. Add missing pieces. 1166 * Completely offline nodes stay around and they just need 1167 * reintialization. 1168 */ 1169 pgdat = NODE_DATA(nid); 1170 1171 /* init node's zones as empty zones, we don't have any present pages.*/ 1172 free_area_init_core_hotplug(pgdat); 1173 1174 /* 1175 * The node we allocated has no zone fallback lists. For avoiding 1176 * to access not-initialized zonelist, build here. 1177 */ 1178 build_all_zonelists(pgdat); 1179 1180 return pgdat; 1181 } 1182 1183 /* 1184 * __try_online_node - online a node if offlined 1185 * @nid: the node ID 1186 * @set_node_online: Whether we want to online the node 1187 * called by cpu_up() to online a node without onlined memory. 1188 * 1189 * Returns: 1190 * 1 -> a new node has been allocated 1191 * 0 -> the node is already online 1192 * -ENOMEM -> the node could not be allocated 1193 */ 1194 static int __try_online_node(int nid, bool set_node_online) 1195 { 1196 pg_data_t *pgdat; 1197 int ret = 1; 1198 1199 if (node_online(nid)) 1200 return 0; 1201 1202 pgdat = hotadd_init_pgdat(nid); 1203 if (!pgdat) { 1204 pr_err("Cannot online node %d due to NULL pgdat\n", nid); 1205 ret = -ENOMEM; 1206 goto out; 1207 } 1208 1209 if (set_node_online) { 1210 node_set_online(nid); 1211 ret = register_one_node(nid); 1212 BUG_ON(ret); 1213 } 1214 out: 1215 return ret; 1216 } 1217 1218 /* 1219 * Users of this function always want to online/register the node 1220 */ 1221 int try_online_node(int nid) 1222 { 1223 int ret; 1224 1225 mem_hotplug_begin(); 1226 ret = __try_online_node(nid, true); 1227 mem_hotplug_done(); 1228 return ret; 1229 } 1230 1231 static int check_hotplug_memory_range(u64 start, u64 size) 1232 { 1233 /* memory range must be block size aligned */ 1234 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) || 1235 !IS_ALIGNED(size, memory_block_size_bytes())) { 1236 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx", 1237 memory_block_size_bytes(), start, size); 1238 return -EINVAL; 1239 } 1240 1241 return 0; 1242 } 1243 1244 static int online_memory_block(struct memory_block *mem, void *arg) 1245 { 1246 mem->online_type = mhp_default_online_type; 1247 return device_online(&mem->dev); 1248 } 1249 1250 bool mhp_supports_memmap_on_memory(unsigned long size) 1251 { 1252 unsigned long nr_vmemmap_pages = size / PAGE_SIZE; 1253 unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page); 1254 unsigned long remaining_size = size - vmemmap_size; 1255 1256 /* 1257 * Besides having arch support and the feature enabled at runtime, we 1258 * need a few more assumptions to hold true: 1259 * 1260 * a) We span a single memory block: memory onlining/offlinin;g happens 1261 * in memory block granularity. We don't want the vmemmap of online 1262 * memory blocks to reside on offline memory blocks. In the future, 1263 * we might want to support variable-sized memory blocks to make the 1264 * feature more versatile. 1265 * 1266 * b) The vmemmap pages span complete PMDs: We don't want vmemmap code 1267 * to populate memory from the altmap for unrelated parts (i.e., 1268 * other memory blocks) 1269 * 1270 * c) The vmemmap pages (and thereby the pages that will be exposed to 1271 * the buddy) have to cover full pageblocks: memory onlining/offlining 1272 * code requires applicable ranges to be page-aligned, for example, to 1273 * set the migratetypes properly. 1274 * 1275 * TODO: Although we have a check here to make sure that vmemmap pages 1276 * fully populate a PMD, it is not the right place to check for 1277 * this. A much better solution involves improving vmemmap code 1278 * to fallback to base pages when trying to populate vmemmap using 1279 * altmap as an alternative source of memory, and we do not exactly 1280 * populate a single PMD. 1281 */ 1282 return mhp_memmap_on_memory() && 1283 size == memory_block_size_bytes() && 1284 IS_ALIGNED(vmemmap_size, PMD_SIZE) && 1285 IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT)); 1286 } 1287 1288 /* 1289 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 1290 * and online/offline operations (triggered e.g. by sysfs). 1291 * 1292 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG 1293 */ 1294 int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) 1295 { 1296 struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; 1297 enum memblock_flags memblock_flags = MEMBLOCK_NONE; 1298 struct vmem_altmap mhp_altmap = {}; 1299 struct memory_group *group = NULL; 1300 u64 start, size; 1301 bool new_node = false; 1302 int ret; 1303 1304 start = res->start; 1305 size = resource_size(res); 1306 1307 ret = check_hotplug_memory_range(start, size); 1308 if (ret) 1309 return ret; 1310 1311 if (mhp_flags & MHP_NID_IS_MGID) { 1312 group = memory_group_find_by_id(nid); 1313 if (!group) 1314 return -EINVAL; 1315 nid = group->nid; 1316 } 1317 1318 if (!node_possible(nid)) { 1319 WARN(1, "node %d was absent from the node_possible_map\n", nid); 1320 return -EINVAL; 1321 } 1322 1323 mem_hotplug_begin(); 1324 1325 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { 1326 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED) 1327 memblock_flags = MEMBLOCK_DRIVER_MANAGED; 1328 ret = memblock_add_node(start, size, nid, memblock_flags); 1329 if (ret) 1330 goto error_mem_hotplug_end; 1331 } 1332 1333 ret = __try_online_node(nid, false); 1334 if (ret < 0) 1335 goto error; 1336 new_node = ret; 1337 1338 /* 1339 * Self hosted memmap array 1340 */ 1341 if (mhp_flags & MHP_MEMMAP_ON_MEMORY) { 1342 if (!mhp_supports_memmap_on_memory(size)) { 1343 ret = -EINVAL; 1344 goto error; 1345 } 1346 mhp_altmap.free = PHYS_PFN(size); 1347 mhp_altmap.base_pfn = PHYS_PFN(start); 1348 params.altmap = &mhp_altmap; 1349 } 1350 1351 /* call arch's memory hotadd */ 1352 ret = arch_add_memory(nid, start, size, ¶ms); 1353 if (ret < 0) 1354 goto error; 1355 1356 /* create memory block devices after memory was added */ 1357 ret = create_memory_block_devices(start, size, mhp_altmap.alloc, 1358 group); 1359 if (ret) { 1360 arch_remove_memory(start, size, NULL); 1361 goto error; 1362 } 1363 1364 if (new_node) { 1365 /* If sysfs file of new node can't be created, cpu on the node 1366 * can't be hot-added. There is no rollback way now. 1367 * So, check by BUG_ON() to catch it reluctantly.. 1368 * We online node here. We can't roll back from here. 1369 */ 1370 node_set_online(nid); 1371 ret = __register_one_node(nid); 1372 BUG_ON(ret); 1373 } 1374 1375 register_memory_blocks_under_node(nid, PFN_DOWN(start), 1376 PFN_UP(start + size - 1), 1377 MEMINIT_HOTPLUG); 1378 1379 /* create new memmap entry */ 1380 if (!strcmp(res->name, "System RAM")) 1381 firmware_map_add_hotplug(start, start + size, "System RAM"); 1382 1383 /* device_online() will take the lock when calling online_pages() */ 1384 mem_hotplug_done(); 1385 1386 /* 1387 * In case we're allowed to merge the resource, flag it and trigger 1388 * merging now that adding succeeded. 1389 */ 1390 if (mhp_flags & MHP_MERGE_RESOURCE) 1391 merge_system_ram_resource(res); 1392 1393 /* online pages if requested */ 1394 if (mhp_default_online_type != MMOP_OFFLINE) 1395 walk_memory_blocks(start, size, NULL, online_memory_block); 1396 1397 return ret; 1398 error: 1399 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) 1400 memblock_remove(start, size); 1401 error_mem_hotplug_end: 1402 mem_hotplug_done(); 1403 return ret; 1404 } 1405 1406 /* requires device_hotplug_lock, see add_memory_resource() */ 1407 int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) 1408 { 1409 struct resource *res; 1410 int ret; 1411 1412 res = register_memory_resource(start, size, "System RAM"); 1413 if (IS_ERR(res)) 1414 return PTR_ERR(res); 1415 1416 ret = add_memory_resource(nid, res, mhp_flags); 1417 if (ret < 0) 1418 release_memory_resource(res); 1419 return ret; 1420 } 1421 1422 int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) 1423 { 1424 int rc; 1425 1426 lock_device_hotplug(); 1427 rc = __add_memory(nid, start, size, mhp_flags); 1428 unlock_device_hotplug(); 1429 1430 return rc; 1431 } 1432 EXPORT_SYMBOL_GPL(add_memory); 1433 1434 /* 1435 * Add special, driver-managed memory to the system as system RAM. Such 1436 * memory is not exposed via the raw firmware-provided memmap as system 1437 * RAM, instead, it is detected and added by a driver - during cold boot, 1438 * after a reboot, and after kexec. 1439 * 1440 * Reasons why this memory should not be used for the initial memmap of a 1441 * kexec kernel or for placing kexec images: 1442 * - The booting kernel is in charge of determining how this memory will be 1443 * used (e.g., use persistent memory as system RAM) 1444 * - Coordination with a hypervisor is required before this memory 1445 * can be used (e.g., inaccessible parts). 1446 * 1447 * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided 1448 * memory map") are created. Also, the created memory resource is flagged 1449 * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case 1450 * this memory as well (esp., not place kexec images onto it). 1451 * 1452 * The resource_name (visible via /proc/iomem) has to have the format 1453 * "System RAM ($DRIVER)". 1454 */ 1455 int add_memory_driver_managed(int nid, u64 start, u64 size, 1456 const char *resource_name, mhp_t mhp_flags) 1457 { 1458 struct resource *res; 1459 int rc; 1460 1461 if (!resource_name || 1462 strstr(resource_name, "System RAM (") != resource_name || 1463 resource_name[strlen(resource_name) - 1] != ')') 1464 return -EINVAL; 1465 1466 lock_device_hotplug(); 1467 1468 res = register_memory_resource(start, size, resource_name); 1469 if (IS_ERR(res)) { 1470 rc = PTR_ERR(res); 1471 goto out_unlock; 1472 } 1473 1474 rc = add_memory_resource(nid, res, mhp_flags); 1475 if (rc < 0) 1476 release_memory_resource(res); 1477 1478 out_unlock: 1479 unlock_device_hotplug(); 1480 return rc; 1481 } 1482 EXPORT_SYMBOL_GPL(add_memory_driver_managed); 1483 1484 /* 1485 * Platforms should define arch_get_mappable_range() that provides 1486 * maximum possible addressable physical memory range for which the 1487 * linear mapping could be created. The platform returned address 1488 * range must adhere to these following semantics. 1489 * 1490 * - range.start <= range.end 1491 * - Range includes both end points [range.start..range.end] 1492 * 1493 * There is also a fallback definition provided here, allowing the 1494 * entire possible physical address range in case any platform does 1495 * not define arch_get_mappable_range(). 1496 */ 1497 struct range __weak arch_get_mappable_range(void) 1498 { 1499 struct range mhp_range = { 1500 .start = 0UL, 1501 .end = -1ULL, 1502 }; 1503 return mhp_range; 1504 } 1505 1506 struct range mhp_get_pluggable_range(bool need_mapping) 1507 { 1508 const u64 max_phys = (1ULL << MAX_PHYSMEM_BITS) - 1; 1509 struct range mhp_range; 1510 1511 if (need_mapping) { 1512 mhp_range = arch_get_mappable_range(); 1513 if (mhp_range.start > max_phys) { 1514 mhp_range.start = 0; 1515 mhp_range.end = 0; 1516 } 1517 mhp_range.end = min_t(u64, mhp_range.end, max_phys); 1518 } else { 1519 mhp_range.start = 0; 1520 mhp_range.end = max_phys; 1521 } 1522 return mhp_range; 1523 } 1524 EXPORT_SYMBOL_GPL(mhp_get_pluggable_range); 1525 1526 bool mhp_range_allowed(u64 start, u64 size, bool need_mapping) 1527 { 1528 struct range mhp_range = mhp_get_pluggable_range(need_mapping); 1529 u64 end = start + size; 1530 1531 if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end) 1532 return true; 1533 1534 pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n", 1535 start, end, mhp_range.start, mhp_range.end); 1536 return false; 1537 } 1538 1539 #ifdef CONFIG_MEMORY_HOTREMOVE 1540 /* 1541 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages, 1542 * non-lru movable pages and hugepages). Will skip over most unmovable 1543 * pages (esp., pages that can be skipped when offlining), but bail out on 1544 * definitely unmovable pages. 1545 * 1546 * Returns: 1547 * 0 in case a movable page is found and movable_pfn was updated. 1548 * -ENOENT in case no movable page was found. 1549 * -EBUSY in case a definitely unmovable page was found. 1550 */ 1551 static int scan_movable_pages(unsigned long start, unsigned long end, 1552 unsigned long *movable_pfn) 1553 { 1554 unsigned long pfn; 1555 1556 for (pfn = start; pfn < end; pfn++) { 1557 struct page *page, *head; 1558 unsigned long skip; 1559 1560 if (!pfn_valid(pfn)) 1561 continue; 1562 page = pfn_to_page(pfn); 1563 if (PageLRU(page)) 1564 goto found; 1565 if (__PageMovable(page)) 1566 goto found; 1567 1568 /* 1569 * PageOffline() pages that are not marked __PageMovable() and 1570 * have a reference count > 0 (after MEM_GOING_OFFLINE) are 1571 * definitely unmovable. If their reference count would be 0, 1572 * they could at least be skipped when offlining memory. 1573 */ 1574 if (PageOffline(page) && page_count(page)) 1575 return -EBUSY; 1576 1577 if (!PageHuge(page)) 1578 continue; 1579 head = compound_head(page); 1580 /* 1581 * This test is racy as we hold no reference or lock. The 1582 * hugetlb page could have been free'ed and head is no longer 1583 * a hugetlb page before the following check. In such unlikely 1584 * cases false positives and negatives are possible. Calling 1585 * code must deal with these scenarios. 1586 */ 1587 if (HPageMigratable(head)) 1588 goto found; 1589 skip = compound_nr(head) - (page - head); 1590 pfn += skip - 1; 1591 } 1592 return -ENOENT; 1593 found: 1594 *movable_pfn = pfn; 1595 return 0; 1596 } 1597 1598 static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 1599 { 1600 unsigned long pfn; 1601 struct page *page, *head; 1602 LIST_HEAD(source); 1603 static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL, 1604 DEFAULT_RATELIMIT_BURST); 1605 1606 for (pfn = start_pfn; pfn < end_pfn; pfn++) { 1607 struct folio *folio; 1608 bool isolated; 1609 1610 if (!pfn_valid(pfn)) 1611 continue; 1612 page = pfn_to_page(pfn); 1613 folio = page_folio(page); 1614 head = &folio->page; 1615 1616 if (PageHuge(page)) { 1617 pfn = page_to_pfn(head) + compound_nr(head) - 1; 1618 isolate_hugetlb(folio, &source); 1619 continue; 1620 } else if (PageTransHuge(page)) 1621 pfn = page_to_pfn(head) + thp_nr_pages(page) - 1; 1622 1623 /* 1624 * HWPoison pages have elevated reference counts so the migration would 1625 * fail on them. It also doesn't make any sense to migrate them in the 1626 * first place. Still try to unmap such a page in case it is still mapped 1627 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep 1628 * the unmap as the catch all safety net). 1629 */ 1630 if (PageHWPoison(page)) { 1631 if (WARN_ON(folio_test_lru(folio))) 1632 folio_isolate_lru(folio); 1633 if (folio_mapped(folio)) 1634 try_to_unmap(folio, TTU_IGNORE_MLOCK); 1635 continue; 1636 } 1637 1638 if (!get_page_unless_zero(page)) 1639 continue; 1640 /* 1641 * We can skip free pages. And we can deal with pages on 1642 * LRU and non-lru movable pages. 1643 */ 1644 if (PageLRU(page)) 1645 isolated = isolate_lru_page(page); 1646 else 1647 isolated = isolate_movable_page(page, ISOLATE_UNEVICTABLE); 1648 if (isolated) { 1649 list_add_tail(&page->lru, &source); 1650 if (!__PageMovable(page)) 1651 inc_node_page_state(page, NR_ISOLATED_ANON + 1652 page_is_file_lru(page)); 1653 1654 } else { 1655 if (__ratelimit(&migrate_rs)) { 1656 pr_warn("failed to isolate pfn %lx\n", pfn); 1657 dump_page(page, "isolation failed"); 1658 } 1659 } 1660 put_page(page); 1661 } 1662 if (!list_empty(&source)) { 1663 nodemask_t nmask = node_states[N_MEMORY]; 1664 struct migration_target_control mtc = { 1665 .nmask = &nmask, 1666 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, 1667 }; 1668 int ret; 1669 1670 /* 1671 * We have checked that migration range is on a single zone so 1672 * we can use the nid of the first page to all the others. 1673 */ 1674 mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru)); 1675 1676 /* 1677 * try to allocate from a different node but reuse this node 1678 * if there are no other online nodes to be used (e.g. we are 1679 * offlining a part of the only existing node) 1680 */ 1681 node_clear(mtc.nid, nmask); 1682 if (nodes_empty(nmask)) 1683 node_set(mtc.nid, nmask); 1684 ret = migrate_pages(&source, alloc_migration_target, NULL, 1685 (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL); 1686 if (ret) { 1687 list_for_each_entry(page, &source, lru) { 1688 if (__ratelimit(&migrate_rs)) { 1689 pr_warn("migrating pfn %lx failed ret:%d\n", 1690 page_to_pfn(page), ret); 1691 dump_page(page, "migration failure"); 1692 } 1693 } 1694 putback_movable_pages(&source); 1695 } 1696 } 1697 } 1698 1699 static int __init cmdline_parse_movable_node(char *p) 1700 { 1701 movable_node_enabled = true; 1702 return 0; 1703 } 1704 early_param("movable_node", cmdline_parse_movable_node); 1705 1706 /* check which state of node_states will be changed when offline memory */ 1707 static void node_states_check_changes_offline(unsigned long nr_pages, 1708 struct zone *zone, struct memory_notify *arg) 1709 { 1710 struct pglist_data *pgdat = zone->zone_pgdat; 1711 unsigned long present_pages = 0; 1712 enum zone_type zt; 1713 1714 arg->status_change_nid = NUMA_NO_NODE; 1715 arg->status_change_nid_normal = NUMA_NO_NODE; 1716 1717 /* 1718 * Check whether node_states[N_NORMAL_MEMORY] will be changed. 1719 * If the memory to be offline is within the range 1720 * [0..ZONE_NORMAL], and it is the last present memory there, 1721 * the zones in that range will become empty after the offlining, 1722 * thus we can determine that we need to clear the node from 1723 * node_states[N_NORMAL_MEMORY]. 1724 */ 1725 for (zt = 0; zt <= ZONE_NORMAL; zt++) 1726 present_pages += pgdat->node_zones[zt].present_pages; 1727 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages) 1728 arg->status_change_nid_normal = zone_to_nid(zone); 1729 1730 /* 1731 * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM 1732 * does not apply as we don't support 32bit. 1733 * Here we count the possible pages from ZONE_MOVABLE. 1734 * If after having accounted all the pages, we see that the nr_pages 1735 * to be offlined is over or equal to the accounted pages, 1736 * we know that the node will become empty, and so, we can clear 1737 * it for N_MEMORY as well. 1738 */ 1739 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages; 1740 1741 if (nr_pages >= present_pages) 1742 arg->status_change_nid = zone_to_nid(zone); 1743 } 1744 1745 static void node_states_clear_node(int node, struct memory_notify *arg) 1746 { 1747 if (arg->status_change_nid_normal >= 0) 1748 node_clear_state(node, N_NORMAL_MEMORY); 1749 1750 if (arg->status_change_nid >= 0) 1751 node_clear_state(node, N_MEMORY); 1752 } 1753 1754 static int count_system_ram_pages_cb(unsigned long start_pfn, 1755 unsigned long nr_pages, void *data) 1756 { 1757 unsigned long *nr_system_ram_pages = data; 1758 1759 *nr_system_ram_pages += nr_pages; 1760 return 0; 1761 } 1762 1763 int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages, 1764 struct zone *zone, struct memory_group *group) 1765 { 1766 const unsigned long end_pfn = start_pfn + nr_pages; 1767 unsigned long pfn, system_ram_pages = 0; 1768 const int node = zone_to_nid(zone); 1769 unsigned long flags; 1770 struct memory_notify arg; 1771 char *reason; 1772 int ret; 1773 1774 /* 1775 * {on,off}lining is constrained to full memory sections (or more 1776 * precisely to memory blocks from the user space POV). 1777 * memmap_on_memory is an exception because it reserves initial part 1778 * of the physical memory space for vmemmaps. That space is pageblock 1779 * aligned. 1780 */ 1781 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) || 1782 !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))) 1783 return -EINVAL; 1784 1785 mem_hotplug_begin(); 1786 1787 /* 1788 * Don't allow to offline memory blocks that contain holes. 1789 * Consequently, memory blocks with holes can never get onlined 1790 * via the hotplug path - online_pages() - as hotplugged memory has 1791 * no holes. This way, we e.g., don't have to worry about marking 1792 * memory holes PG_reserved, don't need pfn_valid() checks, and can 1793 * avoid using walk_system_ram_range() later. 1794 */ 1795 walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages, 1796 count_system_ram_pages_cb); 1797 if (system_ram_pages != nr_pages) { 1798 ret = -EINVAL; 1799 reason = "memory holes"; 1800 goto failed_removal; 1801 } 1802 1803 /* 1804 * We only support offlining of memory blocks managed by a single zone, 1805 * checked by calling code. This is just a sanity check that we might 1806 * want to remove in the future. 1807 */ 1808 if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn)) != zone || 1809 page_zone(pfn_to_page(end_pfn - 1)) != zone)) { 1810 ret = -EINVAL; 1811 reason = "multizone range"; 1812 goto failed_removal; 1813 } 1814 1815 /* 1816 * Disable pcplists so that page isolation cannot race with freeing 1817 * in a way that pages from isolated pageblock are left on pcplists. 1818 */ 1819 zone_pcp_disable(zone); 1820 lru_cache_disable(); 1821 1822 /* set above range as isolated */ 1823 ret = start_isolate_page_range(start_pfn, end_pfn, 1824 MIGRATE_MOVABLE, 1825 MEMORY_OFFLINE | REPORT_FAILURE, 1826 GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL); 1827 if (ret) { 1828 reason = "failure to isolate range"; 1829 goto failed_removal_pcplists_disabled; 1830 } 1831 1832 arg.start_pfn = start_pfn; 1833 arg.nr_pages = nr_pages; 1834 node_states_check_changes_offline(nr_pages, zone, &arg); 1835 1836 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 1837 ret = notifier_to_errno(ret); 1838 if (ret) { 1839 reason = "notifier failure"; 1840 goto failed_removal_isolated; 1841 } 1842 1843 do { 1844 pfn = start_pfn; 1845 do { 1846 if (signal_pending(current)) { 1847 ret = -EINTR; 1848 reason = "signal backoff"; 1849 goto failed_removal_isolated; 1850 } 1851 1852 cond_resched(); 1853 1854 ret = scan_movable_pages(pfn, end_pfn, &pfn); 1855 if (!ret) { 1856 /* 1857 * TODO: fatal migration failures should bail 1858 * out 1859 */ 1860 do_migrate_range(pfn, end_pfn); 1861 } 1862 } while (!ret); 1863 1864 if (ret != -ENOENT) { 1865 reason = "unmovable page"; 1866 goto failed_removal_isolated; 1867 } 1868 1869 /* 1870 * Dissolve free hugepages in the memory block before doing 1871 * offlining actually in order to make hugetlbfs's object 1872 * counting consistent. 1873 */ 1874 ret = dissolve_free_huge_pages(start_pfn, end_pfn); 1875 if (ret) { 1876 reason = "failure to dissolve huge pages"; 1877 goto failed_removal_isolated; 1878 } 1879 1880 ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE); 1881 1882 } while (ret); 1883 1884 /* Mark all sections offline and remove free pages from the buddy. */ 1885 __offline_isolated_pages(start_pfn, end_pfn); 1886 pr_debug("Offlined Pages %ld\n", nr_pages); 1887 1888 /* 1889 * The memory sections are marked offline, and the pageblock flags 1890 * effectively stale; nobody should be touching them. Fixup the number 1891 * of isolated pageblocks, memory onlining will properly revert this. 1892 */ 1893 spin_lock_irqsave(&zone->lock, flags); 1894 zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages; 1895 spin_unlock_irqrestore(&zone->lock, flags); 1896 1897 lru_cache_enable(); 1898 zone_pcp_enable(zone); 1899 1900 /* removal success */ 1901 adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages); 1902 adjust_present_page_count(pfn_to_page(start_pfn), group, -nr_pages); 1903 1904 /* reinitialise watermarks and update pcp limits */ 1905 init_per_zone_wmark_min(); 1906 1907 if (!populated_zone(zone)) { 1908 zone_pcp_reset(zone); 1909 build_all_zonelists(NULL); 1910 } 1911 1912 node_states_clear_node(node, &arg); 1913 if (arg.status_change_nid >= 0) { 1914 kcompactd_stop(node); 1915 kswapd_stop(node); 1916 } 1917 1918 writeback_set_ratelimit(); 1919 1920 memory_notify(MEM_OFFLINE, &arg); 1921 remove_pfn_range_from_zone(zone, start_pfn, nr_pages); 1922 mem_hotplug_done(); 1923 return 0; 1924 1925 failed_removal_isolated: 1926 /* pushback to free area */ 1927 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); 1928 memory_notify(MEM_CANCEL_OFFLINE, &arg); 1929 failed_removal_pcplists_disabled: 1930 lru_cache_enable(); 1931 zone_pcp_enable(zone); 1932 failed_removal: 1933 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n", 1934 (unsigned long long) start_pfn << PAGE_SHIFT, 1935 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1, 1936 reason); 1937 mem_hotplug_done(); 1938 return ret; 1939 } 1940 1941 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg) 1942 { 1943 int *nid = arg; 1944 1945 *nid = mem->nid; 1946 if (unlikely(mem->state != MEM_OFFLINE)) { 1947 phys_addr_t beginpa, endpa; 1948 1949 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)); 1950 endpa = beginpa + memory_block_size_bytes() - 1; 1951 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n", 1952 &beginpa, &endpa); 1953 1954 return -EBUSY; 1955 } 1956 return 0; 1957 } 1958 1959 static int get_nr_vmemmap_pages_cb(struct memory_block *mem, void *arg) 1960 { 1961 /* 1962 * If not set, continue with the next block. 1963 */ 1964 return mem->nr_vmemmap_pages; 1965 } 1966 1967 static int check_cpu_on_node(int nid) 1968 { 1969 int cpu; 1970 1971 for_each_present_cpu(cpu) { 1972 if (cpu_to_node(cpu) == nid) 1973 /* 1974 * the cpu on this node isn't removed, and we can't 1975 * offline this node. 1976 */ 1977 return -EBUSY; 1978 } 1979 1980 return 0; 1981 } 1982 1983 static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg) 1984 { 1985 int nid = *(int *)arg; 1986 1987 /* 1988 * If a memory block belongs to multiple nodes, the stored nid is not 1989 * reliable. However, such blocks are always online (e.g., cannot get 1990 * offlined) and, therefore, are still spanned by the node. 1991 */ 1992 return mem->nid == nid ? -EEXIST : 0; 1993 } 1994 1995 /** 1996 * try_offline_node 1997 * @nid: the node ID 1998 * 1999 * Offline a node if all memory sections and cpus of the node are removed. 2000 * 2001 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 2002 * and online/offline operations before this call. 2003 */ 2004 void try_offline_node(int nid) 2005 { 2006 int rc; 2007 2008 /* 2009 * If the node still spans pages (especially ZONE_DEVICE), don't 2010 * offline it. A node spans memory after move_pfn_range_to_zone(), 2011 * e.g., after the memory block was onlined. 2012 */ 2013 if (node_spanned_pages(nid)) 2014 return; 2015 2016 /* 2017 * Especially offline memory blocks might not be spanned by the 2018 * node. They will get spanned by the node once they get onlined. 2019 * However, they link to the node in sysfs and can get onlined later. 2020 */ 2021 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb); 2022 if (rc) 2023 return; 2024 2025 if (check_cpu_on_node(nid)) 2026 return; 2027 2028 /* 2029 * all memory/cpu of this node are removed, we can offline this 2030 * node now. 2031 */ 2032 node_set_offline(nid); 2033 unregister_one_node(nid); 2034 } 2035 EXPORT_SYMBOL(try_offline_node); 2036 2037 static int __ref try_remove_memory(u64 start, u64 size) 2038 { 2039 struct vmem_altmap mhp_altmap = {}; 2040 struct vmem_altmap *altmap = NULL; 2041 unsigned long nr_vmemmap_pages; 2042 int rc = 0, nid = NUMA_NO_NODE; 2043 2044 BUG_ON(check_hotplug_memory_range(start, size)); 2045 2046 /* 2047 * All memory blocks must be offlined before removing memory. Check 2048 * whether all memory blocks in question are offline and return error 2049 * if this is not the case. 2050 * 2051 * While at it, determine the nid. Note that if we'd have mixed nodes, 2052 * we'd only try to offline the last determined one -- which is good 2053 * enough for the cases we care about. 2054 */ 2055 rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb); 2056 if (rc) 2057 return rc; 2058 2059 /* 2060 * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in 2061 * the same granularity it was added - a single memory block. 2062 */ 2063 if (mhp_memmap_on_memory()) { 2064 nr_vmemmap_pages = walk_memory_blocks(start, size, NULL, 2065 get_nr_vmemmap_pages_cb); 2066 if (nr_vmemmap_pages) { 2067 if (size != memory_block_size_bytes()) { 2068 pr_warn("Refuse to remove %#llx - %#llx," 2069 "wrong granularity\n", 2070 start, start + size); 2071 return -EINVAL; 2072 } 2073 2074 /* 2075 * Let remove_pmd_table->free_hugepage_table do the 2076 * right thing if we used vmem_altmap when hot-adding 2077 * the range. 2078 */ 2079 mhp_altmap.alloc = nr_vmemmap_pages; 2080 altmap = &mhp_altmap; 2081 } 2082 } 2083 2084 /* remove memmap entry */ 2085 firmware_map_remove(start, start + size, "System RAM"); 2086 2087 /* 2088 * Memory block device removal under the device_hotplug_lock is 2089 * a barrier against racing online attempts. 2090 */ 2091 remove_memory_block_devices(start, size); 2092 2093 mem_hotplug_begin(); 2094 2095 arch_remove_memory(start, size, altmap); 2096 2097 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { 2098 memblock_phys_free(start, size); 2099 memblock_remove(start, size); 2100 } 2101 2102 release_mem_region_adjustable(start, size); 2103 2104 if (nid != NUMA_NO_NODE) 2105 try_offline_node(nid); 2106 2107 mem_hotplug_done(); 2108 return 0; 2109 } 2110 2111 /** 2112 * __remove_memory - Remove memory if every memory block is offline 2113 * @start: physical address of the region to remove 2114 * @size: size of the region to remove 2115 * 2116 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 2117 * and online/offline operations before this call, as required by 2118 * try_offline_node(). 2119 */ 2120 void __remove_memory(u64 start, u64 size) 2121 { 2122 2123 /* 2124 * trigger BUG() if some memory is not offlined prior to calling this 2125 * function 2126 */ 2127 if (try_remove_memory(start, size)) 2128 BUG(); 2129 } 2130 2131 /* 2132 * Remove memory if every memory block is offline, otherwise return -EBUSY is 2133 * some memory is not offline 2134 */ 2135 int remove_memory(u64 start, u64 size) 2136 { 2137 int rc; 2138 2139 lock_device_hotplug(); 2140 rc = try_remove_memory(start, size); 2141 unlock_device_hotplug(); 2142 2143 return rc; 2144 } 2145 EXPORT_SYMBOL_GPL(remove_memory); 2146 2147 static int try_offline_memory_block(struct memory_block *mem, void *arg) 2148 { 2149 uint8_t online_type = MMOP_ONLINE_KERNEL; 2150 uint8_t **online_types = arg; 2151 struct page *page; 2152 int rc; 2153 2154 /* 2155 * Sense the online_type via the zone of the memory block. Offlining 2156 * with multiple zones within one memory block will be rejected 2157 * by offlining code ... so we don't care about that. 2158 */ 2159 page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr)); 2160 if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE) 2161 online_type = MMOP_ONLINE_MOVABLE; 2162 2163 rc = device_offline(&mem->dev); 2164 /* 2165 * Default is MMOP_OFFLINE - change it only if offlining succeeded, 2166 * so try_reonline_memory_block() can do the right thing. 2167 */ 2168 if (!rc) 2169 **online_types = online_type; 2170 2171 (*online_types)++; 2172 /* Ignore if already offline. */ 2173 return rc < 0 ? rc : 0; 2174 } 2175 2176 static int try_reonline_memory_block(struct memory_block *mem, void *arg) 2177 { 2178 uint8_t **online_types = arg; 2179 int rc; 2180 2181 if (**online_types != MMOP_OFFLINE) { 2182 mem->online_type = **online_types; 2183 rc = device_online(&mem->dev); 2184 if (rc < 0) 2185 pr_warn("%s: Failed to re-online memory: %d", 2186 __func__, rc); 2187 } 2188 2189 /* Continue processing all remaining memory blocks. */ 2190 (*online_types)++; 2191 return 0; 2192 } 2193 2194 /* 2195 * Try to offline and remove memory. Might take a long time to finish in case 2196 * memory is still in use. Primarily useful for memory devices that logically 2197 * unplugged all memory (so it's no longer in use) and want to offline + remove 2198 * that memory. 2199 */ 2200 int offline_and_remove_memory(u64 start, u64 size) 2201 { 2202 const unsigned long mb_count = size / memory_block_size_bytes(); 2203 uint8_t *online_types, *tmp; 2204 int rc; 2205 2206 if (!IS_ALIGNED(start, memory_block_size_bytes()) || 2207 !IS_ALIGNED(size, memory_block_size_bytes()) || !size) 2208 return -EINVAL; 2209 2210 /* 2211 * We'll remember the old online type of each memory block, so we can 2212 * try to revert whatever we did when offlining one memory block fails 2213 * after offlining some others succeeded. 2214 */ 2215 online_types = kmalloc_array(mb_count, sizeof(*online_types), 2216 GFP_KERNEL); 2217 if (!online_types) 2218 return -ENOMEM; 2219 /* 2220 * Initialize all states to MMOP_OFFLINE, so when we abort processing in 2221 * try_offline_memory_block(), we'll skip all unprocessed blocks in 2222 * try_reonline_memory_block(). 2223 */ 2224 memset(online_types, MMOP_OFFLINE, mb_count); 2225 2226 lock_device_hotplug(); 2227 2228 tmp = online_types; 2229 rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block); 2230 2231 /* 2232 * In case we succeeded to offline all memory, remove it. 2233 * This cannot fail as it cannot get onlined in the meantime. 2234 */ 2235 if (!rc) { 2236 rc = try_remove_memory(start, size); 2237 if (rc) 2238 pr_err("%s: Failed to remove memory: %d", __func__, rc); 2239 } 2240 2241 /* 2242 * Rollback what we did. While memory onlining might theoretically fail 2243 * (nacked by a notifier), it barely ever happens. 2244 */ 2245 if (rc) { 2246 tmp = online_types; 2247 walk_memory_blocks(start, size, &tmp, 2248 try_reonline_memory_block); 2249 } 2250 unlock_device_hotplug(); 2251 2252 kfree(online_types); 2253 return rc; 2254 } 2255 EXPORT_SYMBOL_GPL(offline_and_remove_memory); 2256 #endif /* CONFIG_MEMORY_HOTREMOVE */ 2257