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/vmalloc.h> 25 #include <linux/ioport.h> 26 #include <linux/delay.h> 27 #include <linux/migrate.h> 28 #include <linux/page-isolation.h> 29 #include <linux/pfn.h> 30 #include <linux/suspend.h> 31 #include <linux/mm_inline.h> 32 #include <linux/firmware-map.h> 33 #include <linux/stop_machine.h> 34 #include <linux/hugetlb.h> 35 #include <linux/memblock.h> 36 #include <linux/compaction.h> 37 #include <linux/rmap.h> 38 #include <linux/module.h> 39 40 #include <asm/tlbflush.h> 41 42 #include "internal.h" 43 #include "shuffle.h" 44 45 #ifdef CONFIG_MHP_MEMMAP_ON_MEMORY 46 /* 47 * memory_hotplug.memmap_on_memory parameter 48 */ 49 static bool memmap_on_memory __ro_after_init; 50 module_param(memmap_on_memory, bool, 0444); 51 MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug"); 52 53 static inline bool mhp_memmap_on_memory(void) 54 { 55 return memmap_on_memory; 56 } 57 #else 58 static inline bool mhp_memmap_on_memory(void) 59 { 60 return false; 61 } 62 #endif 63 64 enum { 65 ONLINE_POLICY_CONTIG_ZONES = 0, 66 ONLINE_POLICY_AUTO_MOVABLE, 67 }; 68 69 static const char * const online_policy_to_str[] = { 70 [ONLINE_POLICY_CONTIG_ZONES] = "contig-zones", 71 [ONLINE_POLICY_AUTO_MOVABLE] = "auto-movable", 72 }; 73 74 static int set_online_policy(const char *val, const struct kernel_param *kp) 75 { 76 int ret = sysfs_match_string(online_policy_to_str, val); 77 78 if (ret < 0) 79 return ret; 80 *((int *)kp->arg) = ret; 81 return 0; 82 } 83 84 static int get_online_policy(char *buffer, const struct kernel_param *kp) 85 { 86 return sprintf(buffer, "%s\n", online_policy_to_str[*((int *)kp->arg)]); 87 } 88 89 /* 90 * memory_hotplug.online_policy: configure online behavior when onlining without 91 * specifying a zone (MMOP_ONLINE) 92 * 93 * "contig-zones": keep zone contiguous 94 * "auto-movable": online memory to ZONE_MOVABLE if the configuration 95 * (auto_movable_ratio, auto_movable_numa_aware) allows for it 96 */ 97 static int online_policy __read_mostly = ONLINE_POLICY_CONTIG_ZONES; 98 static const struct kernel_param_ops online_policy_ops = { 99 .set = set_online_policy, 100 .get = get_online_policy, 101 }; 102 module_param_cb(online_policy, &online_policy_ops, &online_policy, 0644); 103 MODULE_PARM_DESC(online_policy, 104 "Set the online policy (\"contig-zones\", \"auto-movable\") " 105 "Default: \"contig-zones\""); 106 107 /* 108 * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio 109 * 110 * The ratio represent an upper limit and the kernel might decide to not 111 * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory 112 * doesn't allow for more MOVABLE memory. 113 */ 114 static unsigned int auto_movable_ratio __read_mostly = 301; 115 module_param(auto_movable_ratio, uint, 0644); 116 MODULE_PARM_DESC(auto_movable_ratio, 117 "Set the maximum ratio of MOVABLE:KERNEL memory in the system " 118 "in percent for \"auto-movable\" online policy. Default: 301"); 119 120 /* 121 * memory_hotplug.auto_movable_numa_aware: consider numa node stats 122 */ 123 #ifdef CONFIG_NUMA 124 static bool auto_movable_numa_aware __read_mostly = true; 125 module_param(auto_movable_numa_aware, bool, 0644); 126 MODULE_PARM_DESC(auto_movable_numa_aware, 127 "Consider numa node stats in addition to global stats in " 128 "\"auto-movable\" online policy. Default: true"); 129 #endif /* CONFIG_NUMA */ 130 131 /* 132 * online_page_callback contains pointer to current page onlining function. 133 * Initially it is generic_online_page(). If it is required it could be 134 * changed by calling set_online_page_callback() for callback registration 135 * and restore_online_page_callback() for generic callback restore. 136 */ 137 138 static online_page_callback_t online_page_callback = generic_online_page; 139 static DEFINE_MUTEX(online_page_callback_lock); 140 141 DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock); 142 143 void get_online_mems(void) 144 { 145 percpu_down_read(&mem_hotplug_lock); 146 } 147 148 void put_online_mems(void) 149 { 150 percpu_up_read(&mem_hotplug_lock); 151 } 152 153 bool movable_node_enabled = false; 154 155 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE 156 int mhp_default_online_type = MMOP_OFFLINE; 157 #else 158 int mhp_default_online_type = MMOP_ONLINE; 159 #endif 160 161 static int __init setup_memhp_default_state(char *str) 162 { 163 const int online_type = mhp_online_type_from_str(str); 164 165 if (online_type >= 0) 166 mhp_default_online_type = online_type; 167 168 return 1; 169 } 170 __setup("memhp_default_state=", setup_memhp_default_state); 171 172 void mem_hotplug_begin(void) 173 { 174 cpus_read_lock(); 175 percpu_down_write(&mem_hotplug_lock); 176 } 177 178 void mem_hotplug_done(void) 179 { 180 percpu_up_write(&mem_hotplug_lock); 181 cpus_read_unlock(); 182 } 183 184 u64 max_mem_size = U64_MAX; 185 186 /* add this memory to iomem resource */ 187 static struct resource *register_memory_resource(u64 start, u64 size, 188 const char *resource_name) 189 { 190 struct resource *res; 191 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; 192 193 if (strcmp(resource_name, "System RAM")) 194 flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED; 195 196 if (!mhp_range_allowed(start, size, true)) 197 return ERR_PTR(-E2BIG); 198 199 /* 200 * Make sure value parsed from 'mem=' only restricts memory adding 201 * while booting, so that memory hotplug won't be impacted. Please 202 * refer to document of 'mem=' in kernel-parameters.txt for more 203 * details. 204 */ 205 if (start + size > max_mem_size && system_state < SYSTEM_RUNNING) 206 return ERR_PTR(-E2BIG); 207 208 /* 209 * Request ownership of the new memory range. This might be 210 * a child of an existing resource that was present but 211 * not marked as busy. 212 */ 213 res = __request_region(&iomem_resource, start, size, 214 resource_name, flags); 215 216 if (!res) { 217 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n", 218 start, start + size); 219 return ERR_PTR(-EEXIST); 220 } 221 return res; 222 } 223 224 static void release_memory_resource(struct resource *res) 225 { 226 if (!res) 227 return; 228 release_resource(res); 229 kfree(res); 230 } 231 232 static int check_pfn_span(unsigned long pfn, unsigned long nr_pages) 233 { 234 /* 235 * Disallow all operations smaller than a sub-section and only 236 * allow operations smaller than a section for 237 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range() 238 * enforces a larger memory_block_size_bytes() granularity for 239 * memory that will be marked online, so this check should only 240 * fire for direct arch_{add,remove}_memory() users outside of 241 * add_memory_resource(). 242 */ 243 unsigned long min_align; 244 245 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) 246 min_align = PAGES_PER_SUBSECTION; 247 else 248 min_align = PAGES_PER_SECTION; 249 if (!IS_ALIGNED(pfn | nr_pages, min_align)) 250 return -EINVAL; 251 return 0; 252 } 253 254 /* 255 * Return page for the valid pfn only if the page is online. All pfn 256 * walkers which rely on the fully initialized page->flags and others 257 * should use this rather than pfn_valid && pfn_to_page 258 */ 259 struct page *pfn_to_online_page(unsigned long pfn) 260 { 261 unsigned long nr = pfn_to_section_nr(pfn); 262 struct dev_pagemap *pgmap; 263 struct mem_section *ms; 264 265 if (nr >= NR_MEM_SECTIONS) 266 return NULL; 267 268 ms = __nr_to_section(nr); 269 if (!online_section(ms)) 270 return NULL; 271 272 /* 273 * Save some code text when online_section() + 274 * pfn_section_valid() are sufficient. 275 */ 276 if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn)) 277 return NULL; 278 279 if (!pfn_section_valid(ms, pfn)) 280 return NULL; 281 282 if (!online_device_section(ms)) 283 return pfn_to_page(pfn); 284 285 /* 286 * Slowpath: when ZONE_DEVICE collides with 287 * ZONE_{NORMAL,MOVABLE} within the same section some pfns in 288 * the section may be 'offline' but 'valid'. Only 289 * get_dev_pagemap() can determine sub-section online status. 290 */ 291 pgmap = get_dev_pagemap(pfn, NULL); 292 put_dev_pagemap(pgmap); 293 294 /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */ 295 if (pgmap) 296 return NULL; 297 298 return pfn_to_page(pfn); 299 } 300 EXPORT_SYMBOL_GPL(pfn_to_online_page); 301 302 int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages, 303 struct mhp_params *params) 304 { 305 const unsigned long end_pfn = pfn + nr_pages; 306 unsigned long cur_nr_pages; 307 int err; 308 struct vmem_altmap *altmap = params->altmap; 309 310 if (WARN_ON_ONCE(!pgprot_val(params->pgprot))) 311 return -EINVAL; 312 313 VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false)); 314 315 if (altmap) { 316 /* 317 * Validate altmap is within bounds of the total request 318 */ 319 if (altmap->base_pfn != pfn 320 || vmem_altmap_offset(altmap) > nr_pages) { 321 pr_warn_once("memory add fail, invalid altmap\n"); 322 return -EINVAL; 323 } 324 altmap->alloc = 0; 325 } 326 327 if (check_pfn_span(pfn, nr_pages)) { 328 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1); 329 return -EINVAL; 330 } 331 332 for (; pfn < end_pfn; pfn += cur_nr_pages) { 333 /* Select all remaining pages up to the next section boundary */ 334 cur_nr_pages = min(end_pfn - pfn, 335 SECTION_ALIGN_UP(pfn + 1) - pfn); 336 err = sparse_add_section(nid, pfn, cur_nr_pages, altmap, 337 params->pgmap); 338 if (err) 339 break; 340 cond_resched(); 341 } 342 vmemmap_populate_print_last(); 343 return err; 344 } 345 346 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */ 347 static unsigned long find_smallest_section_pfn(int nid, struct zone *zone, 348 unsigned long start_pfn, 349 unsigned long end_pfn) 350 { 351 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) { 352 if (unlikely(!pfn_to_online_page(start_pfn))) 353 continue; 354 355 if (unlikely(pfn_to_nid(start_pfn) != nid)) 356 continue; 357 358 if (zone != page_zone(pfn_to_page(start_pfn))) 359 continue; 360 361 return start_pfn; 362 } 363 364 return 0; 365 } 366 367 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */ 368 static unsigned long find_biggest_section_pfn(int nid, struct zone *zone, 369 unsigned long start_pfn, 370 unsigned long end_pfn) 371 { 372 unsigned long pfn; 373 374 /* pfn is the end pfn of a memory section. */ 375 pfn = end_pfn - 1; 376 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) { 377 if (unlikely(!pfn_to_online_page(pfn))) 378 continue; 379 380 if (unlikely(pfn_to_nid(pfn) != nid)) 381 continue; 382 383 if (zone != page_zone(pfn_to_page(pfn))) 384 continue; 385 386 return pfn; 387 } 388 389 return 0; 390 } 391 392 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, 393 unsigned long end_pfn) 394 { 395 unsigned long pfn; 396 int nid = zone_to_nid(zone); 397 398 if (zone->zone_start_pfn == start_pfn) { 399 /* 400 * If the section is smallest section in the zone, it need 401 * shrink zone->zone_start_pfn and zone->zone_spanned_pages. 402 * In this case, we find second smallest valid mem_section 403 * for shrinking zone. 404 */ 405 pfn = find_smallest_section_pfn(nid, zone, end_pfn, 406 zone_end_pfn(zone)); 407 if (pfn) { 408 zone->spanned_pages = zone_end_pfn(zone) - pfn; 409 zone->zone_start_pfn = pfn; 410 } else { 411 zone->zone_start_pfn = 0; 412 zone->spanned_pages = 0; 413 } 414 } else if (zone_end_pfn(zone) == end_pfn) { 415 /* 416 * If the section is biggest section in the zone, it need 417 * shrink zone->spanned_pages. 418 * In this case, we find second biggest valid mem_section for 419 * shrinking zone. 420 */ 421 pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn, 422 start_pfn); 423 if (pfn) 424 zone->spanned_pages = pfn - zone->zone_start_pfn + 1; 425 else { 426 zone->zone_start_pfn = 0; 427 zone->spanned_pages = 0; 428 } 429 } 430 } 431 432 static void update_pgdat_span(struct pglist_data *pgdat) 433 { 434 unsigned long node_start_pfn = 0, node_end_pfn = 0; 435 struct zone *zone; 436 437 for (zone = pgdat->node_zones; 438 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) { 439 unsigned long end_pfn = zone_end_pfn(zone); 440 441 /* No need to lock the zones, they can't change. */ 442 if (!zone->spanned_pages) 443 continue; 444 if (!node_end_pfn) { 445 node_start_pfn = zone->zone_start_pfn; 446 node_end_pfn = end_pfn; 447 continue; 448 } 449 450 if (end_pfn > node_end_pfn) 451 node_end_pfn = end_pfn; 452 if (zone->zone_start_pfn < node_start_pfn) 453 node_start_pfn = zone->zone_start_pfn; 454 } 455 456 pgdat->node_start_pfn = node_start_pfn; 457 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn; 458 } 459 460 void __ref remove_pfn_range_from_zone(struct zone *zone, 461 unsigned long start_pfn, 462 unsigned long nr_pages) 463 { 464 const unsigned long end_pfn = start_pfn + nr_pages; 465 struct pglist_data *pgdat = zone->zone_pgdat; 466 unsigned long pfn, cur_nr_pages; 467 468 /* Poison struct pages because they are now uninitialized again. */ 469 for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) { 470 cond_resched(); 471 472 /* Select all remaining pages up to the next section boundary */ 473 cur_nr_pages = 474 min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn); 475 page_init_poison(pfn_to_page(pfn), 476 sizeof(struct page) * cur_nr_pages); 477 } 478 479 /* 480 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So 481 * we will not try to shrink the zones - which is okay as 482 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way. 483 */ 484 if (zone_is_zone_device(zone)) 485 return; 486 487 clear_zone_contiguous(zone); 488 489 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages); 490 update_pgdat_span(pgdat); 491 492 set_zone_contiguous(zone); 493 } 494 495 /** 496 * __remove_pages() - remove sections of pages 497 * @pfn: starting pageframe (must be aligned to start of a section) 498 * @nr_pages: number of pages to remove (must be multiple of section size) 499 * @altmap: alternative device page map or %NULL if default memmap is used 500 * 501 * Generic helper function to remove section mappings and sysfs entries 502 * for the section of the memory we are removing. Caller needs to make 503 * sure that pages are marked reserved and zones are adjust properly by 504 * calling offline_pages(). 505 */ 506 void __remove_pages(unsigned long pfn, unsigned long nr_pages, 507 struct vmem_altmap *altmap) 508 { 509 const unsigned long end_pfn = pfn + nr_pages; 510 unsigned long cur_nr_pages; 511 512 if (check_pfn_span(pfn, nr_pages)) { 513 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1); 514 return; 515 } 516 517 for (; pfn < end_pfn; pfn += cur_nr_pages) { 518 cond_resched(); 519 /* Select all remaining pages up to the next section boundary */ 520 cur_nr_pages = min(end_pfn - pfn, 521 SECTION_ALIGN_UP(pfn + 1) - pfn); 522 sparse_remove_section(pfn, cur_nr_pages, altmap); 523 } 524 } 525 526 int set_online_page_callback(online_page_callback_t callback) 527 { 528 int rc = -EINVAL; 529 530 get_online_mems(); 531 mutex_lock(&online_page_callback_lock); 532 533 if (online_page_callback == generic_online_page) { 534 online_page_callback = callback; 535 rc = 0; 536 } 537 538 mutex_unlock(&online_page_callback_lock); 539 put_online_mems(); 540 541 return rc; 542 } 543 EXPORT_SYMBOL_GPL(set_online_page_callback); 544 545 int restore_online_page_callback(online_page_callback_t callback) 546 { 547 int rc = -EINVAL; 548 549 get_online_mems(); 550 mutex_lock(&online_page_callback_lock); 551 552 if (online_page_callback == callback) { 553 online_page_callback = generic_online_page; 554 rc = 0; 555 } 556 557 mutex_unlock(&online_page_callback_lock); 558 put_online_mems(); 559 560 return rc; 561 } 562 EXPORT_SYMBOL_GPL(restore_online_page_callback); 563 564 void generic_online_page(struct page *page, unsigned int order) 565 { 566 /* 567 * Freeing the page with debug_pagealloc enabled will try to unmap it, 568 * so we should map it first. This is better than introducing a special 569 * case in page freeing fast path. 570 */ 571 debug_pagealloc_map_pages(page, 1 << order); 572 __free_pages_core(page, order); 573 totalram_pages_add(1UL << order); 574 } 575 EXPORT_SYMBOL_GPL(generic_online_page); 576 577 static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages) 578 { 579 const unsigned long end_pfn = start_pfn + nr_pages; 580 unsigned long pfn; 581 582 /* 583 * Online the pages in MAX_ORDER aligned chunks. The callback might 584 * decide to not expose all pages to the buddy (e.g., expose them 585 * later). We account all pages as being online and belonging to this 586 * zone ("present"). 587 * When using memmap_on_memory, the range might not be aligned to 588 * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect 589 * this and the first chunk to online will be pageblock_nr_pages. 590 */ 591 for (pfn = start_pfn; pfn < end_pfn;) { 592 int order; 593 594 /* 595 * Free to online pages in the largest chunks alignment allows. 596 * 597 * __ffs() behaviour is undefined for 0. start == 0 is 598 * MAX_ORDER-aligned, Set order to MAX_ORDER for the case. 599 */ 600 if (pfn) 601 order = min_t(int, MAX_ORDER, __ffs(pfn)); 602 else 603 order = MAX_ORDER; 604 605 (*online_page_callback)(pfn_to_page(pfn), order); 606 pfn += (1UL << order); 607 } 608 609 /* mark all involved sections as online */ 610 online_mem_sections(start_pfn, end_pfn); 611 } 612 613 /* check which state of node_states will be changed when online memory */ 614 static void node_states_check_changes_online(unsigned long nr_pages, 615 struct zone *zone, struct memory_notify *arg) 616 { 617 int nid = zone_to_nid(zone); 618 619 arg->status_change_nid = NUMA_NO_NODE; 620 arg->status_change_nid_normal = NUMA_NO_NODE; 621 622 if (!node_state(nid, N_MEMORY)) 623 arg->status_change_nid = nid; 624 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY)) 625 arg->status_change_nid_normal = nid; 626 } 627 628 static void node_states_set_node(int node, struct memory_notify *arg) 629 { 630 if (arg->status_change_nid_normal >= 0) 631 node_set_state(node, N_NORMAL_MEMORY); 632 633 if (arg->status_change_nid >= 0) 634 node_set_state(node, N_MEMORY); 635 } 636 637 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn, 638 unsigned long nr_pages) 639 { 640 unsigned long old_end_pfn = zone_end_pfn(zone); 641 642 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn) 643 zone->zone_start_pfn = start_pfn; 644 645 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn; 646 } 647 648 static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn, 649 unsigned long nr_pages) 650 { 651 unsigned long old_end_pfn = pgdat_end_pfn(pgdat); 652 653 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn) 654 pgdat->node_start_pfn = start_pfn; 655 656 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn; 657 658 } 659 660 #ifdef CONFIG_ZONE_DEVICE 661 static void section_taint_zone_device(unsigned long pfn) 662 { 663 struct mem_section *ms = __pfn_to_section(pfn); 664 665 ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE; 666 } 667 #else 668 static inline void section_taint_zone_device(unsigned long pfn) 669 { 670 } 671 #endif 672 673 /* 674 * Associate the pfn range with the given zone, initializing the memmaps 675 * and resizing the pgdat/zone data to span the added pages. After this 676 * call, all affected pages are PG_reserved. 677 * 678 * All aligned pageblocks are initialized to the specified migratetype 679 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related 680 * zone stats (e.g., nr_isolate_pageblock) are touched. 681 */ 682 void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, 683 unsigned long nr_pages, 684 struct vmem_altmap *altmap, int migratetype) 685 { 686 struct pglist_data *pgdat = zone->zone_pgdat; 687 int nid = pgdat->node_id; 688 689 clear_zone_contiguous(zone); 690 691 if (zone_is_empty(zone)) 692 init_currently_empty_zone(zone, start_pfn, nr_pages); 693 resize_zone_range(zone, start_pfn, nr_pages); 694 resize_pgdat_range(pgdat, start_pfn, nr_pages); 695 696 /* 697 * Subsection population requires care in pfn_to_online_page(). 698 * Set the taint to enable the slow path detection of 699 * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE} 700 * section. 701 */ 702 if (zone_is_zone_device(zone)) { 703 if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION)) 704 section_taint_zone_device(start_pfn); 705 if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)) 706 section_taint_zone_device(start_pfn + nr_pages); 707 } 708 709 /* 710 * TODO now we have a visible range of pages which are not associated 711 * with their zone properly. Not nice but set_pfnblock_flags_mask 712 * expects the zone spans the pfn range. All the pages in the range 713 * are reserved so nobody should be touching them so we should be safe 714 */ 715 memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0, 716 MEMINIT_HOTPLUG, altmap, migratetype); 717 718 set_zone_contiguous(zone); 719 } 720 721 struct auto_movable_stats { 722 unsigned long kernel_early_pages; 723 unsigned long movable_pages; 724 }; 725 726 static void auto_movable_stats_account_zone(struct auto_movable_stats *stats, 727 struct zone *zone) 728 { 729 if (zone_idx(zone) == ZONE_MOVABLE) { 730 stats->movable_pages += zone->present_pages; 731 } else { 732 stats->kernel_early_pages += zone->present_early_pages; 733 #ifdef CONFIG_CMA 734 /* 735 * CMA pages (never on hotplugged memory) behave like 736 * ZONE_MOVABLE. 737 */ 738 stats->movable_pages += zone->cma_pages; 739 stats->kernel_early_pages -= zone->cma_pages; 740 #endif /* CONFIG_CMA */ 741 } 742 } 743 struct auto_movable_group_stats { 744 unsigned long movable_pages; 745 unsigned long req_kernel_early_pages; 746 }; 747 748 static int auto_movable_stats_account_group(struct memory_group *group, 749 void *arg) 750 { 751 const int ratio = READ_ONCE(auto_movable_ratio); 752 struct auto_movable_group_stats *stats = arg; 753 long pages; 754 755 /* 756 * We don't support modifying the config while the auto-movable online 757 * policy is already enabled. Just avoid the division by zero below. 758 */ 759 if (!ratio) 760 return 0; 761 762 /* 763 * Calculate how many early kernel pages this group requires to 764 * satisfy the configured zone ratio. 765 */ 766 pages = group->present_movable_pages * 100 / ratio; 767 pages -= group->present_kernel_pages; 768 769 if (pages > 0) 770 stats->req_kernel_early_pages += pages; 771 stats->movable_pages += group->present_movable_pages; 772 return 0; 773 } 774 775 static bool auto_movable_can_online_movable(int nid, struct memory_group *group, 776 unsigned long nr_pages) 777 { 778 unsigned long kernel_early_pages, movable_pages; 779 struct auto_movable_group_stats group_stats = {}; 780 struct auto_movable_stats stats = {}; 781 pg_data_t *pgdat = NODE_DATA(nid); 782 struct zone *zone; 783 int i; 784 785 /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */ 786 if (nid == NUMA_NO_NODE) { 787 /* TODO: cache values */ 788 for_each_populated_zone(zone) 789 auto_movable_stats_account_zone(&stats, zone); 790 } else { 791 for (i = 0; i < MAX_NR_ZONES; i++) { 792 zone = pgdat->node_zones + i; 793 if (populated_zone(zone)) 794 auto_movable_stats_account_zone(&stats, zone); 795 } 796 } 797 798 kernel_early_pages = stats.kernel_early_pages; 799 movable_pages = stats.movable_pages; 800 801 /* 802 * Kernel memory inside dynamic memory group allows for more MOVABLE 803 * memory within the same group. Remove the effect of all but the 804 * current group from the stats. 805 */ 806 walk_dynamic_memory_groups(nid, auto_movable_stats_account_group, 807 group, &group_stats); 808 if (kernel_early_pages <= group_stats.req_kernel_early_pages) 809 return false; 810 kernel_early_pages -= group_stats.req_kernel_early_pages; 811 movable_pages -= group_stats.movable_pages; 812 813 if (group && group->is_dynamic) 814 kernel_early_pages += group->present_kernel_pages; 815 816 /* 817 * Test if we could online the given number of pages to ZONE_MOVABLE 818 * and still stay in the configured ratio. 819 */ 820 movable_pages += nr_pages; 821 return movable_pages <= (auto_movable_ratio * kernel_early_pages) / 100; 822 } 823 824 /* 825 * Returns a default kernel memory zone for the given pfn range. 826 * If no kernel zone covers this pfn range it will automatically go 827 * to the ZONE_NORMAL. 828 */ 829 static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn, 830 unsigned long nr_pages) 831 { 832 struct pglist_data *pgdat = NODE_DATA(nid); 833 int zid; 834 835 for (zid = 0; zid < ZONE_NORMAL; zid++) { 836 struct zone *zone = &pgdat->node_zones[zid]; 837 838 if (zone_intersects(zone, start_pfn, nr_pages)) 839 return zone; 840 } 841 842 return &pgdat->node_zones[ZONE_NORMAL]; 843 } 844 845 /* 846 * Determine to which zone to online memory dynamically based on user 847 * configuration and system stats. We care about the following ratio: 848 * 849 * MOVABLE : KERNEL 850 * 851 * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in 852 * one of the kernel zones. CMA pages inside one of the kernel zones really 853 * behaves like ZONE_MOVABLE, so we treat them accordingly. 854 * 855 * We don't allow for hotplugged memory in a KERNEL zone to increase the 856 * amount of MOVABLE memory we can have, so we end up with: 857 * 858 * MOVABLE : KERNEL_EARLY 859 * 860 * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze 861 * boot. We base our calculation on KERNEL_EARLY internally, because: 862 * 863 * a) Hotplugged memory in one of the kernel zones can sometimes still get 864 * hotunplugged, especially when hot(un)plugging individual memory blocks. 865 * There is no coordination across memory devices, therefore "automatic" 866 * hotunplugging, as implemented in hypervisors, could result in zone 867 * imbalances. 868 * b) Early/boot memory in one of the kernel zones can usually not get 869 * hotunplugged again (e.g., no firmware interface to unplug, fragmented 870 * with unmovable allocations). While there are corner cases where it might 871 * still work, it is barely relevant in practice. 872 * 873 * Exceptions are dynamic memory groups, which allow for more MOVABLE 874 * memory within the same memory group -- because in that case, there is 875 * coordination within the single memory device managed by a single driver. 876 * 877 * We rely on "present pages" instead of "managed pages", as the latter is 878 * highly unreliable and dynamic in virtualized environments, and does not 879 * consider boot time allocations. For example, memory ballooning adjusts the 880 * managed pages when inflating/deflating the balloon, and balloon compaction 881 * can even migrate inflated pages between zones. 882 * 883 * Using "present pages" is better but some things to keep in mind are: 884 * 885 * a) Some memblock allocations, such as for the crashkernel area, are 886 * effectively unused by the kernel, yet they account to "present pages". 887 * Fortunately, these allocations are comparatively small in relevant setups 888 * (e.g., fraction of system memory). 889 * b) Some hotplugged memory blocks in virtualized environments, esecially 890 * hotplugged by virtio-mem, look like they are completely present, however, 891 * only parts of the memory block are actually currently usable. 892 * "present pages" is an upper limit that can get reached at runtime. As 893 * we base our calculations on KERNEL_EARLY, this is not an issue. 894 */ 895 static struct zone *auto_movable_zone_for_pfn(int nid, 896 struct memory_group *group, 897 unsigned long pfn, 898 unsigned long nr_pages) 899 { 900 unsigned long online_pages = 0, max_pages, end_pfn; 901 struct page *page; 902 903 if (!auto_movable_ratio) 904 goto kernel_zone; 905 906 if (group && !group->is_dynamic) { 907 max_pages = group->s.max_pages; 908 online_pages = group->present_movable_pages; 909 910 /* If anything is !MOVABLE online the rest !MOVABLE. */ 911 if (group->present_kernel_pages) 912 goto kernel_zone; 913 } else if (!group || group->d.unit_pages == nr_pages) { 914 max_pages = nr_pages; 915 } else { 916 max_pages = group->d.unit_pages; 917 /* 918 * Take a look at all online sections in the current unit. 919 * We can safely assume that all pages within a section belong 920 * to the same zone, because dynamic memory groups only deal 921 * with hotplugged memory. 922 */ 923 pfn = ALIGN_DOWN(pfn, group->d.unit_pages); 924 end_pfn = pfn + group->d.unit_pages; 925 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 926 page = pfn_to_online_page(pfn); 927 if (!page) 928 continue; 929 /* If anything is !MOVABLE online the rest !MOVABLE. */ 930 if (!is_zone_movable_page(page)) 931 goto kernel_zone; 932 online_pages += PAGES_PER_SECTION; 933 } 934 } 935 936 /* 937 * Online MOVABLE if we could *currently* online all remaining parts 938 * MOVABLE. We expect to (add+) online them immediately next, so if 939 * nobody interferes, all will be MOVABLE if possible. 940 */ 941 nr_pages = max_pages - online_pages; 942 if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages)) 943 goto kernel_zone; 944 945 #ifdef CONFIG_NUMA 946 if (auto_movable_numa_aware && 947 !auto_movable_can_online_movable(nid, group, nr_pages)) 948 goto kernel_zone; 949 #endif /* CONFIG_NUMA */ 950 951 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 952 kernel_zone: 953 return default_kernel_zone_for_pfn(nid, pfn, nr_pages); 954 } 955 956 static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn, 957 unsigned long nr_pages) 958 { 959 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn, 960 nr_pages); 961 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 962 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages); 963 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages); 964 965 /* 966 * We inherit the existing zone in a simple case where zones do not 967 * overlap in the given range 968 */ 969 if (in_kernel ^ in_movable) 970 return (in_kernel) ? kernel_zone : movable_zone; 971 972 /* 973 * If the range doesn't belong to any zone or two zones overlap in the 974 * given range then we use movable zone only if movable_node is 975 * enabled because we always online to a kernel zone by default. 976 */ 977 return movable_node_enabled ? movable_zone : kernel_zone; 978 } 979 980 struct zone *zone_for_pfn_range(int online_type, int nid, 981 struct memory_group *group, unsigned long start_pfn, 982 unsigned long nr_pages) 983 { 984 if (online_type == MMOP_ONLINE_KERNEL) 985 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages); 986 987 if (online_type == MMOP_ONLINE_MOVABLE) 988 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 989 990 if (online_policy == ONLINE_POLICY_AUTO_MOVABLE) 991 return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages); 992 993 return default_zone_for_pfn(nid, start_pfn, nr_pages); 994 } 995 996 /* 997 * This function should only be called by memory_block_{online,offline}, 998 * and {online,offline}_pages. 999 */ 1000 void adjust_present_page_count(struct page *page, struct memory_group *group, 1001 long nr_pages) 1002 { 1003 struct zone *zone = page_zone(page); 1004 const bool movable = zone_idx(zone) == ZONE_MOVABLE; 1005 1006 /* 1007 * We only support onlining/offlining/adding/removing of complete 1008 * memory blocks; therefore, either all is either early or hotplugged. 1009 */ 1010 if (early_section(__pfn_to_section(page_to_pfn(page)))) 1011 zone->present_early_pages += nr_pages; 1012 zone->present_pages += nr_pages; 1013 zone->zone_pgdat->node_present_pages += nr_pages; 1014 1015 if (group && movable) 1016 group->present_movable_pages += nr_pages; 1017 else if (group && !movable) 1018 group->present_kernel_pages += nr_pages; 1019 } 1020 1021 int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages, 1022 struct zone *zone) 1023 { 1024 unsigned long end_pfn = pfn + nr_pages; 1025 int ret, i; 1026 1027 ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); 1028 if (ret) 1029 return ret; 1030 1031 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE); 1032 1033 for (i = 0; i < nr_pages; i++) 1034 SetPageVmemmapSelfHosted(pfn_to_page(pfn + i)); 1035 1036 /* 1037 * It might be that the vmemmap_pages fully span sections. If that is 1038 * the case, mark those sections online here as otherwise they will be 1039 * left offline. 1040 */ 1041 if (nr_pages >= PAGES_PER_SECTION) 1042 online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION)); 1043 1044 return ret; 1045 } 1046 1047 void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages) 1048 { 1049 unsigned long end_pfn = pfn + nr_pages; 1050 1051 /* 1052 * It might be that the vmemmap_pages fully span sections. If that is 1053 * the case, mark those sections offline here as otherwise they will be 1054 * left online. 1055 */ 1056 if (nr_pages >= PAGES_PER_SECTION) 1057 offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION)); 1058 1059 /* 1060 * The pages associated with this vmemmap have been offlined, so 1061 * we can reset its state here. 1062 */ 1063 remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages); 1064 kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); 1065 } 1066 1067 int __ref online_pages(unsigned long pfn, unsigned long nr_pages, 1068 struct zone *zone, struct memory_group *group) 1069 { 1070 unsigned long flags; 1071 int need_zonelists_rebuild = 0; 1072 const int nid = zone_to_nid(zone); 1073 int ret; 1074 struct memory_notify arg; 1075 1076 /* 1077 * {on,off}lining is constrained to full memory sections (or more 1078 * precisely to memory blocks from the user space POV). 1079 * memmap_on_memory is an exception because it reserves initial part 1080 * of the physical memory space for vmemmaps. That space is pageblock 1081 * aligned. 1082 */ 1083 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) || 1084 !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION))) 1085 return -EINVAL; 1086 1087 mem_hotplug_begin(); 1088 1089 /* associate pfn range with the zone */ 1090 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE); 1091 1092 arg.start_pfn = pfn; 1093 arg.nr_pages = nr_pages; 1094 node_states_check_changes_online(nr_pages, zone, &arg); 1095 1096 ret = memory_notify(MEM_GOING_ONLINE, &arg); 1097 ret = notifier_to_errno(ret); 1098 if (ret) 1099 goto failed_addition; 1100 1101 /* 1102 * Fixup the number of isolated pageblocks before marking the sections 1103 * onlining, such that undo_isolate_page_range() works correctly. 1104 */ 1105 spin_lock_irqsave(&zone->lock, flags); 1106 zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages; 1107 spin_unlock_irqrestore(&zone->lock, flags); 1108 1109 /* 1110 * If this zone is not populated, then it is not in zonelist. 1111 * This means the page allocator ignores this zone. 1112 * So, zonelist must be updated after online. 1113 */ 1114 if (!populated_zone(zone)) { 1115 need_zonelists_rebuild = 1; 1116 setup_zone_pageset(zone); 1117 } 1118 1119 online_pages_range(pfn, nr_pages); 1120 adjust_present_page_count(pfn_to_page(pfn), group, nr_pages); 1121 1122 node_states_set_node(nid, &arg); 1123 if (need_zonelists_rebuild) 1124 build_all_zonelists(NULL); 1125 1126 /* Basic onlining is complete, allow allocation of onlined pages. */ 1127 undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE); 1128 1129 /* 1130 * Freshly onlined pages aren't shuffled (e.g., all pages are placed to 1131 * the tail of the freelist when undoing isolation). Shuffle the whole 1132 * zone to make sure the just onlined pages are properly distributed 1133 * across the whole freelist - to create an initial shuffle. 1134 */ 1135 shuffle_zone(zone); 1136 1137 /* reinitialise watermarks and update pcp limits */ 1138 init_per_zone_wmark_min(); 1139 1140 kswapd_run(nid); 1141 kcompactd_run(nid); 1142 1143 writeback_set_ratelimit(); 1144 1145 memory_notify(MEM_ONLINE, &arg); 1146 mem_hotplug_done(); 1147 return 0; 1148 1149 failed_addition: 1150 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n", 1151 (unsigned long long) pfn << PAGE_SHIFT, 1152 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1); 1153 memory_notify(MEM_CANCEL_ONLINE, &arg); 1154 remove_pfn_range_from_zone(zone, pfn, nr_pages); 1155 mem_hotplug_done(); 1156 return ret; 1157 } 1158 1159 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 1160 static pg_data_t __ref *hotadd_init_pgdat(int nid) 1161 { 1162 struct pglist_data *pgdat; 1163 1164 /* 1165 * NODE_DATA is preallocated (free_area_init) but its internal 1166 * state is not allocated completely. Add missing pieces. 1167 * Completely offline nodes stay around and they just need 1168 * reintialization. 1169 */ 1170 pgdat = NODE_DATA(nid); 1171 1172 /* init node's zones as empty zones, we don't have any present pages.*/ 1173 free_area_init_core_hotplug(pgdat); 1174 1175 /* 1176 * The node we allocated has no zone fallback lists. For avoiding 1177 * to access not-initialized zonelist, build here. 1178 */ 1179 build_all_zonelists(pgdat); 1180 1181 return pgdat; 1182 } 1183 1184 /* 1185 * __try_online_node - online a node if offlined 1186 * @nid: the node ID 1187 * @set_node_online: Whether we want to online the node 1188 * called by cpu_up() to online a node without onlined memory. 1189 * 1190 * Returns: 1191 * 1 -> a new node has been allocated 1192 * 0 -> the node is already online 1193 * -ENOMEM -> the node could not be allocated 1194 */ 1195 static int __try_online_node(int nid, bool set_node_online) 1196 { 1197 pg_data_t *pgdat; 1198 int ret = 1; 1199 1200 if (node_online(nid)) 1201 return 0; 1202 1203 pgdat = hotadd_init_pgdat(nid); 1204 if (!pgdat) { 1205 pr_err("Cannot online node %d due to NULL pgdat\n", nid); 1206 ret = -ENOMEM; 1207 goto out; 1208 } 1209 1210 if (set_node_online) { 1211 node_set_online(nid); 1212 ret = register_one_node(nid); 1213 BUG_ON(ret); 1214 } 1215 out: 1216 return ret; 1217 } 1218 1219 /* 1220 * Users of this function always want to online/register the node 1221 */ 1222 int try_online_node(int nid) 1223 { 1224 int ret; 1225 1226 mem_hotplug_begin(); 1227 ret = __try_online_node(nid, true); 1228 mem_hotplug_done(); 1229 return ret; 1230 } 1231 1232 static int check_hotplug_memory_range(u64 start, u64 size) 1233 { 1234 /* memory range must be block size aligned */ 1235 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) || 1236 !IS_ALIGNED(size, memory_block_size_bytes())) { 1237 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx", 1238 memory_block_size_bytes(), start, size); 1239 return -EINVAL; 1240 } 1241 1242 return 0; 1243 } 1244 1245 static int online_memory_block(struct memory_block *mem, void *arg) 1246 { 1247 mem->online_type = mhp_default_online_type; 1248 return device_online(&mem->dev); 1249 } 1250 1251 bool mhp_supports_memmap_on_memory(unsigned long size) 1252 { 1253 unsigned long nr_vmemmap_pages = size / PAGE_SIZE; 1254 unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page); 1255 unsigned long remaining_size = size - vmemmap_size; 1256 1257 /* 1258 * Besides having arch support and the feature enabled at runtime, we 1259 * need a few more assumptions to hold true: 1260 * 1261 * a) We span a single memory block: memory onlining/offlinin;g happens 1262 * in memory block granularity. We don't want the vmemmap of online 1263 * memory blocks to reside on offline memory blocks. In the future, 1264 * we might want to support variable-sized memory blocks to make the 1265 * feature more versatile. 1266 * 1267 * b) The vmemmap pages span complete PMDs: We don't want vmemmap code 1268 * to populate memory from the altmap for unrelated parts (i.e., 1269 * other memory blocks) 1270 * 1271 * c) The vmemmap pages (and thereby the pages that will be exposed to 1272 * the buddy) have to cover full pageblocks: memory onlining/offlining 1273 * code requires applicable ranges to be page-aligned, for example, to 1274 * set the migratetypes properly. 1275 * 1276 * TODO: Although we have a check here to make sure that vmemmap pages 1277 * fully populate a PMD, it is not the right place to check for 1278 * this. A much better solution involves improving vmemmap code 1279 * to fallback to base pages when trying to populate vmemmap using 1280 * altmap as an alternative source of memory, and we do not exactly 1281 * populate a single PMD. 1282 */ 1283 return mhp_memmap_on_memory() && 1284 size == memory_block_size_bytes() && 1285 IS_ALIGNED(vmemmap_size, PMD_SIZE) && 1286 IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT)); 1287 } 1288 1289 /* 1290 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 1291 * and online/offline operations (triggered e.g. by sysfs). 1292 * 1293 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG 1294 */ 1295 int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) 1296 { 1297 struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; 1298 enum memblock_flags memblock_flags = MEMBLOCK_NONE; 1299 struct vmem_altmap mhp_altmap = {}; 1300 struct memory_group *group = NULL; 1301 u64 start, size; 1302 bool new_node = false; 1303 int ret; 1304 1305 start = res->start; 1306 size = resource_size(res); 1307 1308 ret = check_hotplug_memory_range(start, size); 1309 if (ret) 1310 return ret; 1311 1312 if (mhp_flags & MHP_NID_IS_MGID) { 1313 group = memory_group_find_by_id(nid); 1314 if (!group) 1315 return -EINVAL; 1316 nid = group->nid; 1317 } 1318 1319 if (!node_possible(nid)) { 1320 WARN(1, "node %d was absent from the node_possible_map\n", nid); 1321 return -EINVAL; 1322 } 1323 1324 mem_hotplug_begin(); 1325 1326 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { 1327 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED) 1328 memblock_flags = MEMBLOCK_DRIVER_MANAGED; 1329 ret = memblock_add_node(start, size, nid, memblock_flags); 1330 if (ret) 1331 goto error_mem_hotplug_end; 1332 } 1333 1334 ret = __try_online_node(nid, false); 1335 if (ret < 0) 1336 goto error; 1337 new_node = ret; 1338 1339 /* 1340 * Self hosted memmap array 1341 */ 1342 if (mhp_flags & MHP_MEMMAP_ON_MEMORY) { 1343 if (!mhp_supports_memmap_on_memory(size)) { 1344 ret = -EINVAL; 1345 goto error; 1346 } 1347 mhp_altmap.free = PHYS_PFN(size); 1348 mhp_altmap.base_pfn = PHYS_PFN(start); 1349 params.altmap = &mhp_altmap; 1350 } 1351 1352 /* call arch's memory hotadd */ 1353 ret = arch_add_memory(nid, start, size, ¶ms); 1354 if (ret < 0) 1355 goto error; 1356 1357 /* create memory block devices after memory was added */ 1358 ret = create_memory_block_devices(start, size, mhp_altmap.alloc, 1359 group); 1360 if (ret) { 1361 arch_remove_memory(start, size, NULL); 1362 goto error; 1363 } 1364 1365 if (new_node) { 1366 /* If sysfs file of new node can't be created, cpu on the node 1367 * can't be hot-added. There is no rollback way now. 1368 * So, check by BUG_ON() to catch it reluctantly.. 1369 * We online node here. We can't roll back from here. 1370 */ 1371 node_set_online(nid); 1372 ret = __register_one_node(nid); 1373 BUG_ON(ret); 1374 } 1375 1376 register_memory_blocks_under_node(nid, PFN_DOWN(start), 1377 PFN_UP(start + size - 1), 1378 MEMINIT_HOTPLUG); 1379 1380 /* create new memmap entry */ 1381 if (!strcmp(res->name, "System RAM")) 1382 firmware_map_add_hotplug(start, start + size, "System RAM"); 1383 1384 /* device_online() will take the lock when calling online_pages() */ 1385 mem_hotplug_done(); 1386 1387 /* 1388 * In case we're allowed to merge the resource, flag it and trigger 1389 * merging now that adding succeeded. 1390 */ 1391 if (mhp_flags & MHP_MERGE_RESOURCE) 1392 merge_system_ram_resource(res); 1393 1394 /* online pages if requested */ 1395 if (mhp_default_online_type != MMOP_OFFLINE) 1396 walk_memory_blocks(start, size, NULL, online_memory_block); 1397 1398 return ret; 1399 error: 1400 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) 1401 memblock_remove(start, size); 1402 error_mem_hotplug_end: 1403 mem_hotplug_done(); 1404 return ret; 1405 } 1406 1407 /* requires device_hotplug_lock, see add_memory_resource() */ 1408 int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) 1409 { 1410 struct resource *res; 1411 int ret; 1412 1413 res = register_memory_resource(start, size, "System RAM"); 1414 if (IS_ERR(res)) 1415 return PTR_ERR(res); 1416 1417 ret = add_memory_resource(nid, res, mhp_flags); 1418 if (ret < 0) 1419 release_memory_resource(res); 1420 return ret; 1421 } 1422 1423 int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) 1424 { 1425 int rc; 1426 1427 lock_device_hotplug(); 1428 rc = __add_memory(nid, start, size, mhp_flags); 1429 unlock_device_hotplug(); 1430 1431 return rc; 1432 } 1433 EXPORT_SYMBOL_GPL(add_memory); 1434 1435 /* 1436 * Add special, driver-managed memory to the system as system RAM. Such 1437 * memory is not exposed via the raw firmware-provided memmap as system 1438 * RAM, instead, it is detected and added by a driver - during cold boot, 1439 * after a reboot, and after kexec. 1440 * 1441 * Reasons why this memory should not be used for the initial memmap of a 1442 * kexec kernel or for placing kexec images: 1443 * - The booting kernel is in charge of determining how this memory will be 1444 * used (e.g., use persistent memory as system RAM) 1445 * - Coordination with a hypervisor is required before this memory 1446 * can be used (e.g., inaccessible parts). 1447 * 1448 * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided 1449 * memory map") are created. Also, the created memory resource is flagged 1450 * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case 1451 * this memory as well (esp., not place kexec images onto it). 1452 * 1453 * The resource_name (visible via /proc/iomem) has to have the format 1454 * "System RAM ($DRIVER)". 1455 */ 1456 int add_memory_driver_managed(int nid, u64 start, u64 size, 1457 const char *resource_name, mhp_t mhp_flags) 1458 { 1459 struct resource *res; 1460 int rc; 1461 1462 if (!resource_name || 1463 strstr(resource_name, "System RAM (") != resource_name || 1464 resource_name[strlen(resource_name) - 1] != ')') 1465 return -EINVAL; 1466 1467 lock_device_hotplug(); 1468 1469 res = register_memory_resource(start, size, resource_name); 1470 if (IS_ERR(res)) { 1471 rc = PTR_ERR(res); 1472 goto out_unlock; 1473 } 1474 1475 rc = add_memory_resource(nid, res, mhp_flags); 1476 if (rc < 0) 1477 release_memory_resource(res); 1478 1479 out_unlock: 1480 unlock_device_hotplug(); 1481 return rc; 1482 } 1483 EXPORT_SYMBOL_GPL(add_memory_driver_managed); 1484 1485 /* 1486 * Platforms should define arch_get_mappable_range() that provides 1487 * maximum possible addressable physical memory range for which the 1488 * linear mapping could be created. The platform returned address 1489 * range must adhere to these following semantics. 1490 * 1491 * - range.start <= range.end 1492 * - Range includes both end points [range.start..range.end] 1493 * 1494 * There is also a fallback definition provided here, allowing the 1495 * entire possible physical address range in case any platform does 1496 * not define arch_get_mappable_range(). 1497 */ 1498 struct range __weak arch_get_mappable_range(void) 1499 { 1500 struct range mhp_range = { 1501 .start = 0UL, 1502 .end = -1ULL, 1503 }; 1504 return mhp_range; 1505 } 1506 1507 struct range mhp_get_pluggable_range(bool need_mapping) 1508 { 1509 const u64 max_phys = (1ULL << MAX_PHYSMEM_BITS) - 1; 1510 struct range mhp_range; 1511 1512 if (need_mapping) { 1513 mhp_range = arch_get_mappable_range(); 1514 if (mhp_range.start > max_phys) { 1515 mhp_range.start = 0; 1516 mhp_range.end = 0; 1517 } 1518 mhp_range.end = min_t(u64, mhp_range.end, max_phys); 1519 } else { 1520 mhp_range.start = 0; 1521 mhp_range.end = max_phys; 1522 } 1523 return mhp_range; 1524 } 1525 EXPORT_SYMBOL_GPL(mhp_get_pluggable_range); 1526 1527 bool mhp_range_allowed(u64 start, u64 size, bool need_mapping) 1528 { 1529 struct range mhp_range = mhp_get_pluggable_range(need_mapping); 1530 u64 end = start + size; 1531 1532 if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end) 1533 return true; 1534 1535 pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n", 1536 start, end, mhp_range.start, mhp_range.end); 1537 return false; 1538 } 1539 1540 #ifdef CONFIG_MEMORY_HOTREMOVE 1541 /* 1542 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages, 1543 * non-lru movable pages and hugepages). Will skip over most unmovable 1544 * pages (esp., pages that can be skipped when offlining), but bail out on 1545 * definitely unmovable pages. 1546 * 1547 * Returns: 1548 * 0 in case a movable page is found and movable_pfn was updated. 1549 * -ENOENT in case no movable page was found. 1550 * -EBUSY in case a definitely unmovable page was found. 1551 */ 1552 static int scan_movable_pages(unsigned long start, unsigned long end, 1553 unsigned long *movable_pfn) 1554 { 1555 unsigned long pfn; 1556 1557 for (pfn = start; pfn < end; pfn++) { 1558 struct page *page, *head; 1559 unsigned long skip; 1560 1561 if (!pfn_valid(pfn)) 1562 continue; 1563 page = pfn_to_page(pfn); 1564 if (PageLRU(page)) 1565 goto found; 1566 if (__PageMovable(page)) 1567 goto found; 1568 1569 /* 1570 * PageOffline() pages that are not marked __PageMovable() and 1571 * have a reference count > 0 (after MEM_GOING_OFFLINE) are 1572 * definitely unmovable. If their reference count would be 0, 1573 * they could at least be skipped when offlining memory. 1574 */ 1575 if (PageOffline(page) && page_count(page)) 1576 return -EBUSY; 1577 1578 if (!PageHuge(page)) 1579 continue; 1580 head = compound_head(page); 1581 /* 1582 * This test is racy as we hold no reference or lock. The 1583 * hugetlb page could have been free'ed and head is no longer 1584 * a hugetlb page before the following check. In such unlikely 1585 * cases false positives and negatives are possible. Calling 1586 * code must deal with these scenarios. 1587 */ 1588 if (HPageMigratable(head)) 1589 goto found; 1590 skip = compound_nr(head) - (page - head); 1591 pfn += skip - 1; 1592 } 1593 return -ENOENT; 1594 found: 1595 *movable_pfn = pfn; 1596 return 0; 1597 } 1598 1599 static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 1600 { 1601 unsigned long pfn; 1602 struct page *page, *head; 1603 LIST_HEAD(source); 1604 static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL, 1605 DEFAULT_RATELIMIT_BURST); 1606 1607 for (pfn = start_pfn; pfn < end_pfn; pfn++) { 1608 struct folio *folio; 1609 bool isolated; 1610 1611 if (!pfn_valid(pfn)) 1612 continue; 1613 page = pfn_to_page(pfn); 1614 folio = page_folio(page); 1615 head = &folio->page; 1616 1617 if (PageHuge(page)) { 1618 pfn = page_to_pfn(head) + compound_nr(head) - 1; 1619 isolate_hugetlb(folio, &source); 1620 continue; 1621 } else if (PageTransHuge(page)) 1622 pfn = page_to_pfn(head) + thp_nr_pages(page) - 1; 1623 1624 /* 1625 * HWPoison pages have elevated reference counts so the migration would 1626 * fail on them. It also doesn't make any sense to migrate them in the 1627 * first place. Still try to unmap such a page in case it is still mapped 1628 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep 1629 * the unmap as the catch all safety net). 1630 */ 1631 if (PageHWPoison(page)) { 1632 if (WARN_ON(folio_test_lru(folio))) 1633 folio_isolate_lru(folio); 1634 if (folio_mapped(folio)) 1635 try_to_unmap(folio, TTU_IGNORE_MLOCK); 1636 continue; 1637 } 1638 1639 if (!get_page_unless_zero(page)) 1640 continue; 1641 /* 1642 * We can skip free pages. And we can deal with pages on 1643 * LRU and non-lru movable pages. 1644 */ 1645 if (PageLRU(page)) 1646 isolated = isolate_lru_page(page); 1647 else 1648 isolated = isolate_movable_page(page, ISOLATE_UNEVICTABLE); 1649 if (isolated) { 1650 list_add_tail(&page->lru, &source); 1651 if (!__PageMovable(page)) 1652 inc_node_page_state(page, NR_ISOLATED_ANON + 1653 page_is_file_lru(page)); 1654 1655 } else { 1656 if (__ratelimit(&migrate_rs)) { 1657 pr_warn("failed to isolate pfn %lx\n", pfn); 1658 dump_page(page, "isolation failed"); 1659 } 1660 } 1661 put_page(page); 1662 } 1663 if (!list_empty(&source)) { 1664 nodemask_t nmask = node_states[N_MEMORY]; 1665 struct migration_target_control mtc = { 1666 .nmask = &nmask, 1667 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, 1668 }; 1669 int ret; 1670 1671 /* 1672 * We have checked that migration range is on a single zone so 1673 * we can use the nid of the first page to all the others. 1674 */ 1675 mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru)); 1676 1677 /* 1678 * try to allocate from a different node but reuse this node 1679 * if there are no other online nodes to be used (e.g. we are 1680 * offlining a part of the only existing node) 1681 */ 1682 node_clear(mtc.nid, nmask); 1683 if (nodes_empty(nmask)) 1684 node_set(mtc.nid, nmask); 1685 ret = migrate_pages(&source, alloc_migration_target, NULL, 1686 (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL); 1687 if (ret) { 1688 list_for_each_entry(page, &source, lru) { 1689 if (__ratelimit(&migrate_rs)) { 1690 pr_warn("migrating pfn %lx failed ret:%d\n", 1691 page_to_pfn(page), ret); 1692 dump_page(page, "migration failure"); 1693 } 1694 } 1695 putback_movable_pages(&source); 1696 } 1697 } 1698 } 1699 1700 static int __init cmdline_parse_movable_node(char *p) 1701 { 1702 movable_node_enabled = true; 1703 return 0; 1704 } 1705 early_param("movable_node", cmdline_parse_movable_node); 1706 1707 /* check which state of node_states will be changed when offline memory */ 1708 static void node_states_check_changes_offline(unsigned long nr_pages, 1709 struct zone *zone, struct memory_notify *arg) 1710 { 1711 struct pglist_data *pgdat = zone->zone_pgdat; 1712 unsigned long present_pages = 0; 1713 enum zone_type zt; 1714 1715 arg->status_change_nid = NUMA_NO_NODE; 1716 arg->status_change_nid_normal = NUMA_NO_NODE; 1717 1718 /* 1719 * Check whether node_states[N_NORMAL_MEMORY] will be changed. 1720 * If the memory to be offline is within the range 1721 * [0..ZONE_NORMAL], and it is the last present memory there, 1722 * the zones in that range will become empty after the offlining, 1723 * thus we can determine that we need to clear the node from 1724 * node_states[N_NORMAL_MEMORY]. 1725 */ 1726 for (zt = 0; zt <= ZONE_NORMAL; zt++) 1727 present_pages += pgdat->node_zones[zt].present_pages; 1728 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages) 1729 arg->status_change_nid_normal = zone_to_nid(zone); 1730 1731 /* 1732 * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM 1733 * does not apply as we don't support 32bit. 1734 * Here we count the possible pages from ZONE_MOVABLE. 1735 * If after having accounted all the pages, we see that the nr_pages 1736 * to be offlined is over or equal to the accounted pages, 1737 * we know that the node will become empty, and so, we can clear 1738 * it for N_MEMORY as well. 1739 */ 1740 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages; 1741 1742 if (nr_pages >= present_pages) 1743 arg->status_change_nid = zone_to_nid(zone); 1744 } 1745 1746 static void node_states_clear_node(int node, struct memory_notify *arg) 1747 { 1748 if (arg->status_change_nid_normal >= 0) 1749 node_clear_state(node, N_NORMAL_MEMORY); 1750 1751 if (arg->status_change_nid >= 0) 1752 node_clear_state(node, N_MEMORY); 1753 } 1754 1755 static int count_system_ram_pages_cb(unsigned long start_pfn, 1756 unsigned long nr_pages, void *data) 1757 { 1758 unsigned long *nr_system_ram_pages = data; 1759 1760 *nr_system_ram_pages += nr_pages; 1761 return 0; 1762 } 1763 1764 int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages, 1765 struct zone *zone, struct memory_group *group) 1766 { 1767 const unsigned long end_pfn = start_pfn + nr_pages; 1768 unsigned long pfn, system_ram_pages = 0; 1769 const int node = zone_to_nid(zone); 1770 unsigned long flags; 1771 struct memory_notify arg; 1772 char *reason; 1773 int ret; 1774 1775 /* 1776 * {on,off}lining is constrained to full memory sections (or more 1777 * precisely to memory blocks from the user space POV). 1778 * memmap_on_memory is an exception because it reserves initial part 1779 * of the physical memory space for vmemmaps. That space is pageblock 1780 * aligned. 1781 */ 1782 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) || 1783 !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))) 1784 return -EINVAL; 1785 1786 mem_hotplug_begin(); 1787 1788 /* 1789 * Don't allow to offline memory blocks that contain holes. 1790 * Consequently, memory blocks with holes can never get onlined 1791 * via the hotplug path - online_pages() - as hotplugged memory has 1792 * no holes. This way, we e.g., don't have to worry about marking 1793 * memory holes PG_reserved, don't need pfn_valid() checks, and can 1794 * avoid using walk_system_ram_range() later. 1795 */ 1796 walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages, 1797 count_system_ram_pages_cb); 1798 if (system_ram_pages != nr_pages) { 1799 ret = -EINVAL; 1800 reason = "memory holes"; 1801 goto failed_removal; 1802 } 1803 1804 /* 1805 * We only support offlining of memory blocks managed by a single zone, 1806 * checked by calling code. This is just a sanity check that we might 1807 * want to remove in the future. 1808 */ 1809 if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn)) != zone || 1810 page_zone(pfn_to_page(end_pfn - 1)) != zone)) { 1811 ret = -EINVAL; 1812 reason = "multizone range"; 1813 goto failed_removal; 1814 } 1815 1816 /* 1817 * Disable pcplists so that page isolation cannot race with freeing 1818 * in a way that pages from isolated pageblock are left on pcplists. 1819 */ 1820 zone_pcp_disable(zone); 1821 lru_cache_disable(); 1822 1823 /* set above range as isolated */ 1824 ret = start_isolate_page_range(start_pfn, end_pfn, 1825 MIGRATE_MOVABLE, 1826 MEMORY_OFFLINE | REPORT_FAILURE, 1827 GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL); 1828 if (ret) { 1829 reason = "failure to isolate range"; 1830 goto failed_removal_pcplists_disabled; 1831 } 1832 1833 arg.start_pfn = start_pfn; 1834 arg.nr_pages = nr_pages; 1835 node_states_check_changes_offline(nr_pages, zone, &arg); 1836 1837 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 1838 ret = notifier_to_errno(ret); 1839 if (ret) { 1840 reason = "notifier failure"; 1841 goto failed_removal_isolated; 1842 } 1843 1844 do { 1845 pfn = start_pfn; 1846 do { 1847 if (signal_pending(current)) { 1848 ret = -EINTR; 1849 reason = "signal backoff"; 1850 goto failed_removal_isolated; 1851 } 1852 1853 cond_resched(); 1854 1855 ret = scan_movable_pages(pfn, end_pfn, &pfn); 1856 if (!ret) { 1857 /* 1858 * TODO: fatal migration failures should bail 1859 * out 1860 */ 1861 do_migrate_range(pfn, end_pfn); 1862 } 1863 } while (!ret); 1864 1865 if (ret != -ENOENT) { 1866 reason = "unmovable page"; 1867 goto failed_removal_isolated; 1868 } 1869 1870 /* 1871 * Dissolve free hugepages in the memory block before doing 1872 * offlining actually in order to make hugetlbfs's object 1873 * counting consistent. 1874 */ 1875 ret = dissolve_free_huge_pages(start_pfn, end_pfn); 1876 if (ret) { 1877 reason = "failure to dissolve huge pages"; 1878 goto failed_removal_isolated; 1879 } 1880 1881 ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE); 1882 1883 } while (ret); 1884 1885 /* Mark all sections offline and remove free pages from the buddy. */ 1886 __offline_isolated_pages(start_pfn, end_pfn); 1887 pr_debug("Offlined Pages %ld\n", nr_pages); 1888 1889 /* 1890 * The memory sections are marked offline, and the pageblock flags 1891 * effectively stale; nobody should be touching them. Fixup the number 1892 * of isolated pageblocks, memory onlining will properly revert this. 1893 */ 1894 spin_lock_irqsave(&zone->lock, flags); 1895 zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages; 1896 spin_unlock_irqrestore(&zone->lock, flags); 1897 1898 lru_cache_enable(); 1899 zone_pcp_enable(zone); 1900 1901 /* removal success */ 1902 adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages); 1903 adjust_present_page_count(pfn_to_page(start_pfn), group, -nr_pages); 1904 1905 /* reinitialise watermarks and update pcp limits */ 1906 init_per_zone_wmark_min(); 1907 1908 if (!populated_zone(zone)) { 1909 zone_pcp_reset(zone); 1910 build_all_zonelists(NULL); 1911 } 1912 1913 node_states_clear_node(node, &arg); 1914 if (arg.status_change_nid >= 0) { 1915 kcompactd_stop(node); 1916 kswapd_stop(node); 1917 } 1918 1919 writeback_set_ratelimit(); 1920 1921 memory_notify(MEM_OFFLINE, &arg); 1922 remove_pfn_range_from_zone(zone, start_pfn, nr_pages); 1923 mem_hotplug_done(); 1924 return 0; 1925 1926 failed_removal_isolated: 1927 /* pushback to free area */ 1928 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); 1929 memory_notify(MEM_CANCEL_OFFLINE, &arg); 1930 failed_removal_pcplists_disabled: 1931 lru_cache_enable(); 1932 zone_pcp_enable(zone); 1933 failed_removal: 1934 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n", 1935 (unsigned long long) start_pfn << PAGE_SHIFT, 1936 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1, 1937 reason); 1938 mem_hotplug_done(); 1939 return ret; 1940 } 1941 1942 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg) 1943 { 1944 int *nid = arg; 1945 1946 *nid = mem->nid; 1947 if (unlikely(mem->state != MEM_OFFLINE)) { 1948 phys_addr_t beginpa, endpa; 1949 1950 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)); 1951 endpa = beginpa + memory_block_size_bytes() - 1; 1952 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n", 1953 &beginpa, &endpa); 1954 1955 return -EBUSY; 1956 } 1957 return 0; 1958 } 1959 1960 static int get_nr_vmemmap_pages_cb(struct memory_block *mem, void *arg) 1961 { 1962 /* 1963 * If not set, continue with the next block. 1964 */ 1965 return mem->nr_vmemmap_pages; 1966 } 1967 1968 static int check_cpu_on_node(int nid) 1969 { 1970 int cpu; 1971 1972 for_each_present_cpu(cpu) { 1973 if (cpu_to_node(cpu) == nid) 1974 /* 1975 * the cpu on this node isn't removed, and we can't 1976 * offline this node. 1977 */ 1978 return -EBUSY; 1979 } 1980 1981 return 0; 1982 } 1983 1984 static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg) 1985 { 1986 int nid = *(int *)arg; 1987 1988 /* 1989 * If a memory block belongs to multiple nodes, the stored nid is not 1990 * reliable. However, such blocks are always online (e.g., cannot get 1991 * offlined) and, therefore, are still spanned by the node. 1992 */ 1993 return mem->nid == nid ? -EEXIST : 0; 1994 } 1995 1996 /** 1997 * try_offline_node 1998 * @nid: the node ID 1999 * 2000 * Offline a node if all memory sections and cpus of the node are removed. 2001 * 2002 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 2003 * and online/offline operations before this call. 2004 */ 2005 void try_offline_node(int nid) 2006 { 2007 int rc; 2008 2009 /* 2010 * If the node still spans pages (especially ZONE_DEVICE), don't 2011 * offline it. A node spans memory after move_pfn_range_to_zone(), 2012 * e.g., after the memory block was onlined. 2013 */ 2014 if (node_spanned_pages(nid)) 2015 return; 2016 2017 /* 2018 * Especially offline memory blocks might not be spanned by the 2019 * node. They will get spanned by the node once they get onlined. 2020 * However, they link to the node in sysfs and can get onlined later. 2021 */ 2022 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb); 2023 if (rc) 2024 return; 2025 2026 if (check_cpu_on_node(nid)) 2027 return; 2028 2029 /* 2030 * all memory/cpu of this node are removed, we can offline this 2031 * node now. 2032 */ 2033 node_set_offline(nid); 2034 unregister_one_node(nid); 2035 } 2036 EXPORT_SYMBOL(try_offline_node); 2037 2038 static int __ref try_remove_memory(u64 start, u64 size) 2039 { 2040 struct vmem_altmap mhp_altmap = {}; 2041 struct vmem_altmap *altmap = NULL; 2042 unsigned long nr_vmemmap_pages; 2043 int rc = 0, nid = NUMA_NO_NODE; 2044 2045 BUG_ON(check_hotplug_memory_range(start, size)); 2046 2047 /* 2048 * All memory blocks must be offlined before removing memory. Check 2049 * whether all memory blocks in question are offline and return error 2050 * if this is not the case. 2051 * 2052 * While at it, determine the nid. Note that if we'd have mixed nodes, 2053 * we'd only try to offline the last determined one -- which is good 2054 * enough for the cases we care about. 2055 */ 2056 rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb); 2057 if (rc) 2058 return rc; 2059 2060 /* 2061 * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in 2062 * the same granularity it was added - a single memory block. 2063 */ 2064 if (mhp_memmap_on_memory()) { 2065 nr_vmemmap_pages = walk_memory_blocks(start, size, NULL, 2066 get_nr_vmemmap_pages_cb); 2067 if (nr_vmemmap_pages) { 2068 if (size != memory_block_size_bytes()) { 2069 pr_warn("Refuse to remove %#llx - %#llx," 2070 "wrong granularity\n", 2071 start, start + size); 2072 return -EINVAL; 2073 } 2074 2075 /* 2076 * Let remove_pmd_table->free_hugepage_table do the 2077 * right thing if we used vmem_altmap when hot-adding 2078 * the range. 2079 */ 2080 mhp_altmap.alloc = nr_vmemmap_pages; 2081 altmap = &mhp_altmap; 2082 } 2083 } 2084 2085 /* remove memmap entry */ 2086 firmware_map_remove(start, start + size, "System RAM"); 2087 2088 /* 2089 * Memory block device removal under the device_hotplug_lock is 2090 * a barrier against racing online attempts. 2091 */ 2092 remove_memory_block_devices(start, size); 2093 2094 mem_hotplug_begin(); 2095 2096 arch_remove_memory(start, size, altmap); 2097 2098 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { 2099 memblock_phys_free(start, size); 2100 memblock_remove(start, size); 2101 } 2102 2103 release_mem_region_adjustable(start, size); 2104 2105 if (nid != NUMA_NO_NODE) 2106 try_offline_node(nid); 2107 2108 mem_hotplug_done(); 2109 return 0; 2110 } 2111 2112 /** 2113 * __remove_memory - Remove memory if every memory block is offline 2114 * @start: physical address of the region to remove 2115 * @size: size of the region to remove 2116 * 2117 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 2118 * and online/offline operations before this call, as required by 2119 * try_offline_node(). 2120 */ 2121 void __remove_memory(u64 start, u64 size) 2122 { 2123 2124 /* 2125 * trigger BUG() if some memory is not offlined prior to calling this 2126 * function 2127 */ 2128 if (try_remove_memory(start, size)) 2129 BUG(); 2130 } 2131 2132 /* 2133 * Remove memory if every memory block is offline, otherwise return -EBUSY is 2134 * some memory is not offline 2135 */ 2136 int remove_memory(u64 start, u64 size) 2137 { 2138 int rc; 2139 2140 lock_device_hotplug(); 2141 rc = try_remove_memory(start, size); 2142 unlock_device_hotplug(); 2143 2144 return rc; 2145 } 2146 EXPORT_SYMBOL_GPL(remove_memory); 2147 2148 static int try_offline_memory_block(struct memory_block *mem, void *arg) 2149 { 2150 uint8_t online_type = MMOP_ONLINE_KERNEL; 2151 uint8_t **online_types = arg; 2152 struct page *page; 2153 int rc; 2154 2155 /* 2156 * Sense the online_type via the zone of the memory block. Offlining 2157 * with multiple zones within one memory block will be rejected 2158 * by offlining code ... so we don't care about that. 2159 */ 2160 page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr)); 2161 if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE) 2162 online_type = MMOP_ONLINE_MOVABLE; 2163 2164 rc = device_offline(&mem->dev); 2165 /* 2166 * Default is MMOP_OFFLINE - change it only if offlining succeeded, 2167 * so try_reonline_memory_block() can do the right thing. 2168 */ 2169 if (!rc) 2170 **online_types = online_type; 2171 2172 (*online_types)++; 2173 /* Ignore if already offline. */ 2174 return rc < 0 ? rc : 0; 2175 } 2176 2177 static int try_reonline_memory_block(struct memory_block *mem, void *arg) 2178 { 2179 uint8_t **online_types = arg; 2180 int rc; 2181 2182 if (**online_types != MMOP_OFFLINE) { 2183 mem->online_type = **online_types; 2184 rc = device_online(&mem->dev); 2185 if (rc < 0) 2186 pr_warn("%s: Failed to re-online memory: %d", 2187 __func__, rc); 2188 } 2189 2190 /* Continue processing all remaining memory blocks. */ 2191 (*online_types)++; 2192 return 0; 2193 } 2194 2195 /* 2196 * Try to offline and remove memory. Might take a long time to finish in case 2197 * memory is still in use. Primarily useful for memory devices that logically 2198 * unplugged all memory (so it's no longer in use) and want to offline + remove 2199 * that memory. 2200 */ 2201 int offline_and_remove_memory(u64 start, u64 size) 2202 { 2203 const unsigned long mb_count = size / memory_block_size_bytes(); 2204 uint8_t *online_types, *tmp; 2205 int rc; 2206 2207 if (!IS_ALIGNED(start, memory_block_size_bytes()) || 2208 !IS_ALIGNED(size, memory_block_size_bytes()) || !size) 2209 return -EINVAL; 2210 2211 /* 2212 * We'll remember the old online type of each memory block, so we can 2213 * try to revert whatever we did when offlining one memory block fails 2214 * after offlining some others succeeded. 2215 */ 2216 online_types = kmalloc_array(mb_count, sizeof(*online_types), 2217 GFP_KERNEL); 2218 if (!online_types) 2219 return -ENOMEM; 2220 /* 2221 * Initialize all states to MMOP_OFFLINE, so when we abort processing in 2222 * try_offline_memory_block(), we'll skip all unprocessed blocks in 2223 * try_reonline_memory_block(). 2224 */ 2225 memset(online_types, MMOP_OFFLINE, mb_count); 2226 2227 lock_device_hotplug(); 2228 2229 tmp = online_types; 2230 rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block); 2231 2232 /* 2233 * In case we succeeded to offline all memory, remove it. 2234 * This cannot fail as it cannot get onlined in the meantime. 2235 */ 2236 if (!rc) { 2237 rc = try_remove_memory(start, size); 2238 if (rc) 2239 pr_err("%s: Failed to remove memory: %d", __func__, rc); 2240 } 2241 2242 /* 2243 * Rollback what we did. While memory onlining might theoretically fail 2244 * (nacked by a notifier), it barely ever happens. 2245 */ 2246 if (rc) { 2247 tmp = online_types; 2248 walk_memory_blocks(start, size, &tmp, 2249 try_reonline_memory_block); 2250 } 2251 unlock_device_hotplug(); 2252 2253 kfree(online_types); 2254 return rc; 2255 } 2256 EXPORT_SYMBOL_GPL(offline_and_remove_memory); 2257 #endif /* CONFIG_MEMORY_HOTREMOVE */ 2258