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 enum { 45 MEMMAP_ON_MEMORY_DISABLE = 0, 46 MEMMAP_ON_MEMORY_ENABLE, 47 MEMMAP_ON_MEMORY_FORCE, 48 }; 49 50 static int memmap_mode __read_mostly = MEMMAP_ON_MEMORY_DISABLE; 51 52 static inline unsigned long memory_block_memmap_size(void) 53 { 54 return PHYS_PFN(memory_block_size_bytes()) * sizeof(struct page); 55 } 56 57 static inline unsigned long memory_block_memmap_on_memory_pages(void) 58 { 59 unsigned long nr_pages = PFN_UP(memory_block_memmap_size()); 60 61 /* 62 * In "forced" memmap_on_memory mode, we add extra pages to align the 63 * vmemmap size to cover full pageblocks. That way, we can add memory 64 * even if the vmemmap size is not properly aligned, however, we might waste 65 * memory. 66 */ 67 if (memmap_mode == MEMMAP_ON_MEMORY_FORCE) 68 return pageblock_align(nr_pages); 69 return nr_pages; 70 } 71 72 #ifdef CONFIG_MHP_MEMMAP_ON_MEMORY 73 /* 74 * memory_hotplug.memmap_on_memory parameter 75 */ 76 static int set_memmap_mode(const char *val, const struct kernel_param *kp) 77 { 78 int ret, mode; 79 bool enabled; 80 81 if (sysfs_streq(val, "force") || sysfs_streq(val, "FORCE")) { 82 mode = MEMMAP_ON_MEMORY_FORCE; 83 } else { 84 ret = kstrtobool(val, &enabled); 85 if (ret < 0) 86 return ret; 87 if (enabled) 88 mode = MEMMAP_ON_MEMORY_ENABLE; 89 else 90 mode = MEMMAP_ON_MEMORY_DISABLE; 91 } 92 *((int *)kp->arg) = mode; 93 if (mode == MEMMAP_ON_MEMORY_FORCE) { 94 unsigned long memmap_pages = memory_block_memmap_on_memory_pages(); 95 96 pr_info_once("Memory hotplug will waste %ld pages in each memory block\n", 97 memmap_pages - PFN_UP(memory_block_memmap_size())); 98 } 99 return 0; 100 } 101 102 static int get_memmap_mode(char *buffer, const struct kernel_param *kp) 103 { 104 int mode = *((int *)kp->arg); 105 106 if (mode == MEMMAP_ON_MEMORY_FORCE) 107 return sprintf(buffer, "force\n"); 108 return sprintf(buffer, "%c\n", mode ? 'Y' : 'N'); 109 } 110 111 static const struct kernel_param_ops memmap_mode_ops = { 112 .set = set_memmap_mode, 113 .get = get_memmap_mode, 114 }; 115 module_param_cb(memmap_on_memory, &memmap_mode_ops, &memmap_mode, 0444); 116 MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug\n" 117 "With value \"force\" it could result in memory wastage due " 118 "to memmap size limitations (Y/N/force)"); 119 120 static inline bool mhp_memmap_on_memory(void) 121 { 122 return memmap_mode != MEMMAP_ON_MEMORY_DISABLE; 123 } 124 #else 125 static inline bool mhp_memmap_on_memory(void) 126 { 127 return false; 128 } 129 #endif 130 131 enum { 132 ONLINE_POLICY_CONTIG_ZONES = 0, 133 ONLINE_POLICY_AUTO_MOVABLE, 134 }; 135 136 static const char * const online_policy_to_str[] = { 137 [ONLINE_POLICY_CONTIG_ZONES] = "contig-zones", 138 [ONLINE_POLICY_AUTO_MOVABLE] = "auto-movable", 139 }; 140 141 static int set_online_policy(const char *val, const struct kernel_param *kp) 142 { 143 int ret = sysfs_match_string(online_policy_to_str, val); 144 145 if (ret < 0) 146 return ret; 147 *((int *)kp->arg) = ret; 148 return 0; 149 } 150 151 static int get_online_policy(char *buffer, const struct kernel_param *kp) 152 { 153 return sprintf(buffer, "%s\n", online_policy_to_str[*((int *)kp->arg)]); 154 } 155 156 /* 157 * memory_hotplug.online_policy: configure online behavior when onlining without 158 * specifying a zone (MMOP_ONLINE) 159 * 160 * "contig-zones": keep zone contiguous 161 * "auto-movable": online memory to ZONE_MOVABLE if the configuration 162 * (auto_movable_ratio, auto_movable_numa_aware) allows for it 163 */ 164 static int online_policy __read_mostly = ONLINE_POLICY_CONTIG_ZONES; 165 static const struct kernel_param_ops online_policy_ops = { 166 .set = set_online_policy, 167 .get = get_online_policy, 168 }; 169 module_param_cb(online_policy, &online_policy_ops, &online_policy, 0644); 170 MODULE_PARM_DESC(online_policy, 171 "Set the online policy (\"contig-zones\", \"auto-movable\") " 172 "Default: \"contig-zones\""); 173 174 /* 175 * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio 176 * 177 * The ratio represent an upper limit and the kernel might decide to not 178 * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory 179 * doesn't allow for more MOVABLE memory. 180 */ 181 static unsigned int auto_movable_ratio __read_mostly = 301; 182 module_param(auto_movable_ratio, uint, 0644); 183 MODULE_PARM_DESC(auto_movable_ratio, 184 "Set the maximum ratio of MOVABLE:KERNEL memory in the system " 185 "in percent for \"auto-movable\" online policy. Default: 301"); 186 187 /* 188 * memory_hotplug.auto_movable_numa_aware: consider numa node stats 189 */ 190 #ifdef CONFIG_NUMA 191 static bool auto_movable_numa_aware __read_mostly = true; 192 module_param(auto_movable_numa_aware, bool, 0644); 193 MODULE_PARM_DESC(auto_movable_numa_aware, 194 "Consider numa node stats in addition to global stats in " 195 "\"auto-movable\" online policy. Default: true"); 196 #endif /* CONFIG_NUMA */ 197 198 /* 199 * online_page_callback contains pointer to current page onlining function. 200 * Initially it is generic_online_page(). If it is required it could be 201 * changed by calling set_online_page_callback() for callback registration 202 * and restore_online_page_callback() for generic callback restore. 203 */ 204 205 static online_page_callback_t online_page_callback = generic_online_page; 206 static DEFINE_MUTEX(online_page_callback_lock); 207 208 DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock); 209 210 void get_online_mems(void) 211 { 212 percpu_down_read(&mem_hotplug_lock); 213 } 214 215 void put_online_mems(void) 216 { 217 percpu_up_read(&mem_hotplug_lock); 218 } 219 220 bool movable_node_enabled = false; 221 222 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE 223 int mhp_default_online_type = MMOP_OFFLINE; 224 #else 225 int mhp_default_online_type = MMOP_ONLINE; 226 #endif 227 228 static int __init setup_memhp_default_state(char *str) 229 { 230 const int online_type = mhp_online_type_from_str(str); 231 232 if (online_type >= 0) 233 mhp_default_online_type = online_type; 234 235 return 1; 236 } 237 __setup("memhp_default_state=", setup_memhp_default_state); 238 239 void mem_hotplug_begin(void) 240 { 241 cpus_read_lock(); 242 percpu_down_write(&mem_hotplug_lock); 243 } 244 245 void mem_hotplug_done(void) 246 { 247 percpu_up_write(&mem_hotplug_lock); 248 cpus_read_unlock(); 249 } 250 251 u64 max_mem_size = U64_MAX; 252 253 /* add this memory to iomem resource */ 254 static struct resource *register_memory_resource(u64 start, u64 size, 255 const char *resource_name) 256 { 257 struct resource *res; 258 unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; 259 260 if (strcmp(resource_name, "System RAM")) 261 flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED; 262 263 if (!mhp_range_allowed(start, size, true)) 264 return ERR_PTR(-E2BIG); 265 266 /* 267 * Make sure value parsed from 'mem=' only restricts memory adding 268 * while booting, so that memory hotplug won't be impacted. Please 269 * refer to document of 'mem=' in kernel-parameters.txt for more 270 * details. 271 */ 272 if (start + size > max_mem_size && system_state < SYSTEM_RUNNING) 273 return ERR_PTR(-E2BIG); 274 275 /* 276 * Request ownership of the new memory range. This might be 277 * a child of an existing resource that was present but 278 * not marked as busy. 279 */ 280 res = __request_region(&iomem_resource, start, size, 281 resource_name, flags); 282 283 if (!res) { 284 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n", 285 start, start + size); 286 return ERR_PTR(-EEXIST); 287 } 288 return res; 289 } 290 291 static void release_memory_resource(struct resource *res) 292 { 293 if (!res) 294 return; 295 release_resource(res); 296 kfree(res); 297 } 298 299 static int check_pfn_span(unsigned long pfn, unsigned long nr_pages) 300 { 301 /* 302 * Disallow all operations smaller than a sub-section and only 303 * allow operations smaller than a section for 304 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range() 305 * enforces a larger memory_block_size_bytes() granularity for 306 * memory that will be marked online, so this check should only 307 * fire for direct arch_{add,remove}_memory() users outside of 308 * add_memory_resource(). 309 */ 310 unsigned long min_align; 311 312 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) 313 min_align = PAGES_PER_SUBSECTION; 314 else 315 min_align = PAGES_PER_SECTION; 316 if (!IS_ALIGNED(pfn | nr_pages, min_align)) 317 return -EINVAL; 318 return 0; 319 } 320 321 /* 322 * Return page for the valid pfn only if the page is online. All pfn 323 * walkers which rely on the fully initialized page->flags and others 324 * should use this rather than pfn_valid && pfn_to_page 325 */ 326 struct page *pfn_to_online_page(unsigned long pfn) 327 { 328 unsigned long nr = pfn_to_section_nr(pfn); 329 struct dev_pagemap *pgmap; 330 struct mem_section *ms; 331 332 if (nr >= NR_MEM_SECTIONS) 333 return NULL; 334 335 ms = __nr_to_section(nr); 336 if (!online_section(ms)) 337 return NULL; 338 339 /* 340 * Save some code text when online_section() + 341 * pfn_section_valid() are sufficient. 342 */ 343 if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn)) 344 return NULL; 345 346 if (!pfn_section_valid(ms, pfn)) 347 return NULL; 348 349 if (!online_device_section(ms)) 350 return pfn_to_page(pfn); 351 352 /* 353 * Slowpath: when ZONE_DEVICE collides with 354 * ZONE_{NORMAL,MOVABLE} within the same section some pfns in 355 * the section may be 'offline' but 'valid'. Only 356 * get_dev_pagemap() can determine sub-section online status. 357 */ 358 pgmap = get_dev_pagemap(pfn, NULL); 359 put_dev_pagemap(pgmap); 360 361 /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */ 362 if (pgmap) 363 return NULL; 364 365 return pfn_to_page(pfn); 366 } 367 EXPORT_SYMBOL_GPL(pfn_to_online_page); 368 369 int __add_pages(int nid, unsigned long pfn, unsigned long nr_pages, 370 struct mhp_params *params) 371 { 372 const unsigned long end_pfn = pfn + nr_pages; 373 unsigned long cur_nr_pages; 374 int err; 375 struct vmem_altmap *altmap = params->altmap; 376 377 if (WARN_ON_ONCE(!pgprot_val(params->pgprot))) 378 return -EINVAL; 379 380 VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false)); 381 382 if (altmap) { 383 /* 384 * Validate altmap is within bounds of the total request 385 */ 386 if (altmap->base_pfn != pfn 387 || vmem_altmap_offset(altmap) > nr_pages) { 388 pr_warn_once("memory add fail, invalid altmap\n"); 389 return -EINVAL; 390 } 391 altmap->alloc = 0; 392 } 393 394 if (check_pfn_span(pfn, nr_pages)) { 395 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1); 396 return -EINVAL; 397 } 398 399 for (; pfn < end_pfn; pfn += cur_nr_pages) { 400 /* Select all remaining pages up to the next section boundary */ 401 cur_nr_pages = min(end_pfn - pfn, 402 SECTION_ALIGN_UP(pfn + 1) - pfn); 403 err = sparse_add_section(nid, pfn, cur_nr_pages, altmap, 404 params->pgmap); 405 if (err) 406 break; 407 cond_resched(); 408 } 409 vmemmap_populate_print_last(); 410 return err; 411 } 412 413 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */ 414 static unsigned long find_smallest_section_pfn(int nid, struct zone *zone, 415 unsigned long start_pfn, 416 unsigned long end_pfn) 417 { 418 for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) { 419 if (unlikely(!pfn_to_online_page(start_pfn))) 420 continue; 421 422 if (unlikely(pfn_to_nid(start_pfn) != nid)) 423 continue; 424 425 if (zone != page_zone(pfn_to_page(start_pfn))) 426 continue; 427 428 return start_pfn; 429 } 430 431 return 0; 432 } 433 434 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */ 435 static unsigned long find_biggest_section_pfn(int nid, struct zone *zone, 436 unsigned long start_pfn, 437 unsigned long end_pfn) 438 { 439 unsigned long pfn; 440 441 /* pfn is the end pfn of a memory section. */ 442 pfn = end_pfn - 1; 443 for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) { 444 if (unlikely(!pfn_to_online_page(pfn))) 445 continue; 446 447 if (unlikely(pfn_to_nid(pfn) != nid)) 448 continue; 449 450 if (zone != page_zone(pfn_to_page(pfn))) 451 continue; 452 453 return pfn; 454 } 455 456 return 0; 457 } 458 459 static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, 460 unsigned long end_pfn) 461 { 462 unsigned long pfn; 463 int nid = zone_to_nid(zone); 464 465 if (zone->zone_start_pfn == start_pfn) { 466 /* 467 * If the section is smallest section in the zone, it need 468 * shrink zone->zone_start_pfn and zone->zone_spanned_pages. 469 * In this case, we find second smallest valid mem_section 470 * for shrinking zone. 471 */ 472 pfn = find_smallest_section_pfn(nid, zone, end_pfn, 473 zone_end_pfn(zone)); 474 if (pfn) { 475 zone->spanned_pages = zone_end_pfn(zone) - pfn; 476 zone->zone_start_pfn = pfn; 477 } else { 478 zone->zone_start_pfn = 0; 479 zone->spanned_pages = 0; 480 } 481 } else if (zone_end_pfn(zone) == end_pfn) { 482 /* 483 * If the section is biggest section in the zone, it need 484 * shrink zone->spanned_pages. 485 * In this case, we find second biggest valid mem_section for 486 * shrinking zone. 487 */ 488 pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn, 489 start_pfn); 490 if (pfn) 491 zone->spanned_pages = pfn - zone->zone_start_pfn + 1; 492 else { 493 zone->zone_start_pfn = 0; 494 zone->spanned_pages = 0; 495 } 496 } 497 } 498 499 static void update_pgdat_span(struct pglist_data *pgdat) 500 { 501 unsigned long node_start_pfn = 0, node_end_pfn = 0; 502 struct zone *zone; 503 504 for (zone = pgdat->node_zones; 505 zone < pgdat->node_zones + MAX_NR_ZONES; zone++) { 506 unsigned long end_pfn = zone_end_pfn(zone); 507 508 /* No need to lock the zones, they can't change. */ 509 if (!zone->spanned_pages) 510 continue; 511 if (!node_end_pfn) { 512 node_start_pfn = zone->zone_start_pfn; 513 node_end_pfn = end_pfn; 514 continue; 515 } 516 517 if (end_pfn > node_end_pfn) 518 node_end_pfn = end_pfn; 519 if (zone->zone_start_pfn < node_start_pfn) 520 node_start_pfn = zone->zone_start_pfn; 521 } 522 523 pgdat->node_start_pfn = node_start_pfn; 524 pgdat->node_spanned_pages = node_end_pfn - node_start_pfn; 525 } 526 527 void remove_pfn_range_from_zone(struct zone *zone, 528 unsigned long start_pfn, 529 unsigned long nr_pages) 530 { 531 const unsigned long end_pfn = start_pfn + nr_pages; 532 struct pglist_data *pgdat = zone->zone_pgdat; 533 unsigned long pfn, cur_nr_pages; 534 535 /* Poison struct pages because they are now uninitialized again. */ 536 for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) { 537 cond_resched(); 538 539 /* Select all remaining pages up to the next section boundary */ 540 cur_nr_pages = 541 min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn); 542 page_init_poison(pfn_to_page(pfn), 543 sizeof(struct page) * cur_nr_pages); 544 } 545 546 /* 547 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So 548 * we will not try to shrink the zones - which is okay as 549 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way. 550 */ 551 if (zone_is_zone_device(zone)) 552 return; 553 554 clear_zone_contiguous(zone); 555 556 shrink_zone_span(zone, start_pfn, start_pfn + nr_pages); 557 update_pgdat_span(pgdat); 558 559 set_zone_contiguous(zone); 560 } 561 562 /** 563 * __remove_pages() - remove sections of pages 564 * @pfn: starting pageframe (must be aligned to start of a section) 565 * @nr_pages: number of pages to remove (must be multiple of section size) 566 * @altmap: alternative device page map or %NULL if default memmap is used 567 * 568 * Generic helper function to remove section mappings and sysfs entries 569 * for the section of the memory we are removing. Caller needs to make 570 * sure that pages are marked reserved and zones are adjust properly by 571 * calling offline_pages(). 572 */ 573 void __remove_pages(unsigned long pfn, unsigned long nr_pages, 574 struct vmem_altmap *altmap) 575 { 576 const unsigned long end_pfn = pfn + nr_pages; 577 unsigned long cur_nr_pages; 578 579 if (check_pfn_span(pfn, nr_pages)) { 580 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1); 581 return; 582 } 583 584 for (; pfn < end_pfn; pfn += cur_nr_pages) { 585 cond_resched(); 586 /* Select all remaining pages up to the next section boundary */ 587 cur_nr_pages = min(end_pfn - pfn, 588 SECTION_ALIGN_UP(pfn + 1) - pfn); 589 sparse_remove_section(pfn, cur_nr_pages, altmap); 590 } 591 } 592 593 int set_online_page_callback(online_page_callback_t callback) 594 { 595 int rc = -EINVAL; 596 597 get_online_mems(); 598 mutex_lock(&online_page_callback_lock); 599 600 if (online_page_callback == generic_online_page) { 601 online_page_callback = callback; 602 rc = 0; 603 } 604 605 mutex_unlock(&online_page_callback_lock); 606 put_online_mems(); 607 608 return rc; 609 } 610 EXPORT_SYMBOL_GPL(set_online_page_callback); 611 612 int restore_online_page_callback(online_page_callback_t callback) 613 { 614 int rc = -EINVAL; 615 616 get_online_mems(); 617 mutex_lock(&online_page_callback_lock); 618 619 if (online_page_callback == callback) { 620 online_page_callback = generic_online_page; 621 rc = 0; 622 } 623 624 mutex_unlock(&online_page_callback_lock); 625 put_online_mems(); 626 627 return rc; 628 } 629 EXPORT_SYMBOL_GPL(restore_online_page_callback); 630 631 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 632 void generic_online_page(struct page *page, unsigned int order) 633 { 634 __free_pages_core(page, order, MEMINIT_HOTPLUG); 635 } 636 EXPORT_SYMBOL_GPL(generic_online_page); 637 638 static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages) 639 { 640 const unsigned long end_pfn = start_pfn + nr_pages; 641 unsigned long pfn; 642 643 /* 644 * Online the pages in MAX_PAGE_ORDER aligned chunks. The callback might 645 * decide to not expose all pages to the buddy (e.g., expose them 646 * later). We account all pages as being online and belonging to this 647 * zone ("present"). 648 * When using memmap_on_memory, the range might not be aligned to 649 * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect 650 * this and the first chunk to online will be pageblock_nr_pages. 651 */ 652 for (pfn = start_pfn; pfn < end_pfn;) { 653 int order; 654 655 /* 656 * Free to online pages in the largest chunks alignment allows. 657 * 658 * __ffs() behaviour is undefined for 0. start == 0 is 659 * MAX_PAGE_ORDER-aligned, Set order to MAX_PAGE_ORDER for 660 * the case. 661 */ 662 if (pfn) 663 order = min_t(int, MAX_PAGE_ORDER, __ffs(pfn)); 664 else 665 order = MAX_PAGE_ORDER; 666 667 (*online_page_callback)(pfn_to_page(pfn), order); 668 pfn += (1UL << order); 669 } 670 671 /* mark all involved sections as online */ 672 online_mem_sections(start_pfn, end_pfn); 673 } 674 675 /* check which state of node_states will be changed when online memory */ 676 static void node_states_check_changes_online(unsigned long nr_pages, 677 struct zone *zone, struct memory_notify *arg) 678 { 679 int nid = zone_to_nid(zone); 680 681 arg->status_change_nid = NUMA_NO_NODE; 682 arg->status_change_nid_normal = NUMA_NO_NODE; 683 684 if (!node_state(nid, N_MEMORY)) 685 arg->status_change_nid = nid; 686 if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY)) 687 arg->status_change_nid_normal = nid; 688 } 689 690 static void node_states_set_node(int node, struct memory_notify *arg) 691 { 692 if (arg->status_change_nid_normal >= 0) 693 node_set_state(node, N_NORMAL_MEMORY); 694 695 if (arg->status_change_nid >= 0) 696 node_set_state(node, N_MEMORY); 697 } 698 699 static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn, 700 unsigned long nr_pages) 701 { 702 unsigned long old_end_pfn = zone_end_pfn(zone); 703 704 if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn) 705 zone->zone_start_pfn = start_pfn; 706 707 zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn; 708 } 709 710 static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn, 711 unsigned long nr_pages) 712 { 713 unsigned long old_end_pfn = pgdat_end_pfn(pgdat); 714 715 if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn) 716 pgdat->node_start_pfn = start_pfn; 717 718 pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn; 719 720 } 721 722 #ifdef CONFIG_ZONE_DEVICE 723 static void section_taint_zone_device(unsigned long pfn) 724 { 725 struct mem_section *ms = __pfn_to_section(pfn); 726 727 ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE; 728 } 729 #else 730 static inline void section_taint_zone_device(unsigned long pfn) 731 { 732 } 733 #endif 734 735 /* 736 * Associate the pfn range with the given zone, initializing the memmaps 737 * and resizing the pgdat/zone data to span the added pages. After this 738 * call, all affected pages are PageOffline(). 739 * 740 * All aligned pageblocks are initialized to the specified migratetype 741 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related 742 * zone stats (e.g., nr_isolate_pageblock) are touched. 743 */ 744 void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, 745 unsigned long nr_pages, 746 struct vmem_altmap *altmap, int migratetype) 747 { 748 struct pglist_data *pgdat = zone->zone_pgdat; 749 int nid = pgdat->node_id; 750 751 clear_zone_contiguous(zone); 752 753 if (zone_is_empty(zone)) 754 init_currently_empty_zone(zone, start_pfn, nr_pages); 755 resize_zone_range(zone, start_pfn, nr_pages); 756 resize_pgdat_range(pgdat, start_pfn, nr_pages); 757 758 /* 759 * Subsection population requires care in pfn_to_online_page(). 760 * Set the taint to enable the slow path detection of 761 * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE} 762 * section. 763 */ 764 if (zone_is_zone_device(zone)) { 765 if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION)) 766 section_taint_zone_device(start_pfn); 767 if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)) 768 section_taint_zone_device(start_pfn + nr_pages); 769 } 770 771 /* 772 * TODO now we have a visible range of pages which are not associated 773 * with their zone properly. Not nice but set_pfnblock_flags_mask 774 * expects the zone spans the pfn range. All the pages in the range 775 * are reserved so nobody should be touching them so we should be safe 776 */ 777 memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0, 778 MEMINIT_HOTPLUG, altmap, migratetype); 779 780 set_zone_contiguous(zone); 781 } 782 783 struct auto_movable_stats { 784 unsigned long kernel_early_pages; 785 unsigned long movable_pages; 786 }; 787 788 static void auto_movable_stats_account_zone(struct auto_movable_stats *stats, 789 struct zone *zone) 790 { 791 if (zone_idx(zone) == ZONE_MOVABLE) { 792 stats->movable_pages += zone->present_pages; 793 } else { 794 stats->kernel_early_pages += zone->present_early_pages; 795 #ifdef CONFIG_CMA 796 /* 797 * CMA pages (never on hotplugged memory) behave like 798 * ZONE_MOVABLE. 799 */ 800 stats->movable_pages += zone->cma_pages; 801 stats->kernel_early_pages -= zone->cma_pages; 802 #endif /* CONFIG_CMA */ 803 } 804 } 805 struct auto_movable_group_stats { 806 unsigned long movable_pages; 807 unsigned long req_kernel_early_pages; 808 }; 809 810 static int auto_movable_stats_account_group(struct memory_group *group, 811 void *arg) 812 { 813 const int ratio = READ_ONCE(auto_movable_ratio); 814 struct auto_movable_group_stats *stats = arg; 815 long pages; 816 817 /* 818 * We don't support modifying the config while the auto-movable online 819 * policy is already enabled. Just avoid the division by zero below. 820 */ 821 if (!ratio) 822 return 0; 823 824 /* 825 * Calculate how many early kernel pages this group requires to 826 * satisfy the configured zone ratio. 827 */ 828 pages = group->present_movable_pages * 100 / ratio; 829 pages -= group->present_kernel_pages; 830 831 if (pages > 0) 832 stats->req_kernel_early_pages += pages; 833 stats->movable_pages += group->present_movable_pages; 834 return 0; 835 } 836 837 static bool auto_movable_can_online_movable(int nid, struct memory_group *group, 838 unsigned long nr_pages) 839 { 840 unsigned long kernel_early_pages, movable_pages; 841 struct auto_movable_group_stats group_stats = {}; 842 struct auto_movable_stats stats = {}; 843 struct zone *zone; 844 int i; 845 846 /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */ 847 if (nid == NUMA_NO_NODE) { 848 /* TODO: cache values */ 849 for_each_populated_zone(zone) 850 auto_movable_stats_account_zone(&stats, zone); 851 } else { 852 for (i = 0; i < MAX_NR_ZONES; i++) { 853 pg_data_t *pgdat = NODE_DATA(nid); 854 855 zone = pgdat->node_zones + i; 856 if (populated_zone(zone)) 857 auto_movable_stats_account_zone(&stats, zone); 858 } 859 } 860 861 kernel_early_pages = stats.kernel_early_pages; 862 movable_pages = stats.movable_pages; 863 864 /* 865 * Kernel memory inside dynamic memory group allows for more MOVABLE 866 * memory within the same group. Remove the effect of all but the 867 * current group from the stats. 868 */ 869 walk_dynamic_memory_groups(nid, auto_movable_stats_account_group, 870 group, &group_stats); 871 if (kernel_early_pages <= group_stats.req_kernel_early_pages) 872 return false; 873 kernel_early_pages -= group_stats.req_kernel_early_pages; 874 movable_pages -= group_stats.movable_pages; 875 876 if (group && group->is_dynamic) 877 kernel_early_pages += group->present_kernel_pages; 878 879 /* 880 * Test if we could online the given number of pages to ZONE_MOVABLE 881 * and still stay in the configured ratio. 882 */ 883 movable_pages += nr_pages; 884 return movable_pages <= (auto_movable_ratio * kernel_early_pages) / 100; 885 } 886 887 /* 888 * Returns a default kernel memory zone for the given pfn range. 889 * If no kernel zone covers this pfn range it will automatically go 890 * to the ZONE_NORMAL. 891 */ 892 static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn, 893 unsigned long nr_pages) 894 { 895 struct pglist_data *pgdat = NODE_DATA(nid); 896 int zid; 897 898 for (zid = 0; zid < ZONE_NORMAL; zid++) { 899 struct zone *zone = &pgdat->node_zones[zid]; 900 901 if (zone_intersects(zone, start_pfn, nr_pages)) 902 return zone; 903 } 904 905 return &pgdat->node_zones[ZONE_NORMAL]; 906 } 907 908 /* 909 * Determine to which zone to online memory dynamically based on user 910 * configuration and system stats. We care about the following ratio: 911 * 912 * MOVABLE : KERNEL 913 * 914 * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in 915 * one of the kernel zones. CMA pages inside one of the kernel zones really 916 * behaves like ZONE_MOVABLE, so we treat them accordingly. 917 * 918 * We don't allow for hotplugged memory in a KERNEL zone to increase the 919 * amount of MOVABLE memory we can have, so we end up with: 920 * 921 * MOVABLE : KERNEL_EARLY 922 * 923 * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze 924 * boot. We base our calculation on KERNEL_EARLY internally, because: 925 * 926 * a) Hotplugged memory in one of the kernel zones can sometimes still get 927 * hotunplugged, especially when hot(un)plugging individual memory blocks. 928 * There is no coordination across memory devices, therefore "automatic" 929 * hotunplugging, as implemented in hypervisors, could result in zone 930 * imbalances. 931 * b) Early/boot memory in one of the kernel zones can usually not get 932 * hotunplugged again (e.g., no firmware interface to unplug, fragmented 933 * with unmovable allocations). While there are corner cases where it might 934 * still work, it is barely relevant in practice. 935 * 936 * Exceptions are dynamic memory groups, which allow for more MOVABLE 937 * memory within the same memory group -- because in that case, there is 938 * coordination within the single memory device managed by a single driver. 939 * 940 * We rely on "present pages" instead of "managed pages", as the latter is 941 * highly unreliable and dynamic in virtualized environments, and does not 942 * consider boot time allocations. For example, memory ballooning adjusts the 943 * managed pages when inflating/deflating the balloon, and balloon compaction 944 * can even migrate inflated pages between zones. 945 * 946 * Using "present pages" is better but some things to keep in mind are: 947 * 948 * a) Some memblock allocations, such as for the crashkernel area, are 949 * effectively unused by the kernel, yet they account to "present pages". 950 * Fortunately, these allocations are comparatively small in relevant setups 951 * (e.g., fraction of system memory). 952 * b) Some hotplugged memory blocks in virtualized environments, esecially 953 * hotplugged by virtio-mem, look like they are completely present, however, 954 * only parts of the memory block are actually currently usable. 955 * "present pages" is an upper limit that can get reached at runtime. As 956 * we base our calculations on KERNEL_EARLY, this is not an issue. 957 */ 958 static struct zone *auto_movable_zone_for_pfn(int nid, 959 struct memory_group *group, 960 unsigned long pfn, 961 unsigned long nr_pages) 962 { 963 unsigned long online_pages = 0, max_pages, end_pfn; 964 struct page *page; 965 966 if (!auto_movable_ratio) 967 goto kernel_zone; 968 969 if (group && !group->is_dynamic) { 970 max_pages = group->s.max_pages; 971 online_pages = group->present_movable_pages; 972 973 /* If anything is !MOVABLE online the rest !MOVABLE. */ 974 if (group->present_kernel_pages) 975 goto kernel_zone; 976 } else if (!group || group->d.unit_pages == nr_pages) { 977 max_pages = nr_pages; 978 } else { 979 max_pages = group->d.unit_pages; 980 /* 981 * Take a look at all online sections in the current unit. 982 * We can safely assume that all pages within a section belong 983 * to the same zone, because dynamic memory groups only deal 984 * with hotplugged memory. 985 */ 986 pfn = ALIGN_DOWN(pfn, group->d.unit_pages); 987 end_pfn = pfn + group->d.unit_pages; 988 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 989 page = pfn_to_online_page(pfn); 990 if (!page) 991 continue; 992 /* If anything is !MOVABLE online the rest !MOVABLE. */ 993 if (!is_zone_movable_page(page)) 994 goto kernel_zone; 995 online_pages += PAGES_PER_SECTION; 996 } 997 } 998 999 /* 1000 * Online MOVABLE if we could *currently* online all remaining parts 1001 * MOVABLE. We expect to (add+) online them immediately next, so if 1002 * nobody interferes, all will be MOVABLE if possible. 1003 */ 1004 nr_pages = max_pages - online_pages; 1005 if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages)) 1006 goto kernel_zone; 1007 1008 #ifdef CONFIG_NUMA 1009 if (auto_movable_numa_aware && 1010 !auto_movable_can_online_movable(nid, group, nr_pages)) 1011 goto kernel_zone; 1012 #endif /* CONFIG_NUMA */ 1013 1014 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 1015 kernel_zone: 1016 return default_kernel_zone_for_pfn(nid, pfn, nr_pages); 1017 } 1018 1019 static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn, 1020 unsigned long nr_pages) 1021 { 1022 struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn, 1023 nr_pages); 1024 struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 1025 bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages); 1026 bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages); 1027 1028 /* 1029 * We inherit the existing zone in a simple case where zones do not 1030 * overlap in the given range 1031 */ 1032 if (in_kernel ^ in_movable) 1033 return (in_kernel) ? kernel_zone : movable_zone; 1034 1035 /* 1036 * If the range doesn't belong to any zone or two zones overlap in the 1037 * given range then we use movable zone only if movable_node is 1038 * enabled because we always online to a kernel zone by default. 1039 */ 1040 return movable_node_enabled ? movable_zone : kernel_zone; 1041 } 1042 1043 struct zone *zone_for_pfn_range(int online_type, int nid, 1044 struct memory_group *group, unsigned long start_pfn, 1045 unsigned long nr_pages) 1046 { 1047 if (online_type == MMOP_ONLINE_KERNEL) 1048 return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages); 1049 1050 if (online_type == MMOP_ONLINE_MOVABLE) 1051 return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; 1052 1053 if (online_policy == ONLINE_POLICY_AUTO_MOVABLE) 1054 return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages); 1055 1056 return default_zone_for_pfn(nid, start_pfn, nr_pages); 1057 } 1058 1059 /* 1060 * This function should only be called by memory_block_{online,offline}, 1061 * and {online,offline}_pages. 1062 */ 1063 void adjust_present_page_count(struct page *page, struct memory_group *group, 1064 long nr_pages) 1065 { 1066 struct zone *zone = page_zone(page); 1067 const bool movable = zone_idx(zone) == ZONE_MOVABLE; 1068 1069 /* 1070 * We only support onlining/offlining/adding/removing of complete 1071 * memory blocks; therefore, either all is either early or hotplugged. 1072 */ 1073 if (early_section(__pfn_to_section(page_to_pfn(page)))) 1074 zone->present_early_pages += nr_pages; 1075 zone->present_pages += nr_pages; 1076 zone->zone_pgdat->node_present_pages += nr_pages; 1077 1078 if (group && movable) 1079 group->present_movable_pages += nr_pages; 1080 else if (group && !movable) 1081 group->present_kernel_pages += nr_pages; 1082 } 1083 1084 int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages, 1085 struct zone *zone, bool mhp_off_inaccessible) 1086 { 1087 unsigned long end_pfn = pfn + nr_pages; 1088 int ret, i; 1089 1090 ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); 1091 if (ret) 1092 return ret; 1093 1094 /* 1095 * Memory block is accessible at this stage and hence poison the struct 1096 * pages now. If the memory block is accessible during memory hotplug 1097 * addition phase, then page poisining is already performed in 1098 * sparse_add_section(). 1099 */ 1100 if (mhp_off_inaccessible) 1101 page_init_poison(pfn_to_page(pfn), sizeof(struct page) * nr_pages); 1102 1103 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE); 1104 1105 for (i = 0; i < nr_pages; i++) { 1106 struct page *page = pfn_to_page(pfn + i); 1107 1108 __ClearPageOffline(page); 1109 SetPageVmemmapSelfHosted(page); 1110 } 1111 1112 /* 1113 * It might be that the vmemmap_pages fully span sections. If that is 1114 * the case, mark those sections online here as otherwise they will be 1115 * left offline. 1116 */ 1117 if (nr_pages >= PAGES_PER_SECTION) 1118 online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION)); 1119 1120 return ret; 1121 } 1122 1123 void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages) 1124 { 1125 unsigned long end_pfn = pfn + nr_pages; 1126 1127 /* 1128 * It might be that the vmemmap_pages fully span sections. If that is 1129 * the case, mark those sections offline here as otherwise they will be 1130 * left online. 1131 */ 1132 if (nr_pages >= PAGES_PER_SECTION) 1133 offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION)); 1134 1135 /* 1136 * The pages associated with this vmemmap have been offlined, so 1137 * we can reset its state here. 1138 */ 1139 remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages); 1140 kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); 1141 } 1142 1143 /* 1144 * Must be called with mem_hotplug_lock in write mode. 1145 */ 1146 int online_pages(unsigned long pfn, unsigned long nr_pages, 1147 struct zone *zone, struct memory_group *group) 1148 { 1149 unsigned long flags; 1150 int need_zonelists_rebuild = 0; 1151 const int nid = zone_to_nid(zone); 1152 int ret; 1153 struct memory_notify arg; 1154 1155 /* 1156 * {on,off}lining is constrained to full memory sections (or more 1157 * precisely to memory blocks from the user space POV). 1158 * memmap_on_memory is an exception because it reserves initial part 1159 * of the physical memory space for vmemmaps. That space is pageblock 1160 * aligned. 1161 */ 1162 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) || 1163 !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION))) 1164 return -EINVAL; 1165 1166 1167 /* associate pfn range with the zone */ 1168 move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE); 1169 1170 arg.start_pfn = pfn; 1171 arg.nr_pages = nr_pages; 1172 node_states_check_changes_online(nr_pages, zone, &arg); 1173 1174 ret = memory_notify(MEM_GOING_ONLINE, &arg); 1175 ret = notifier_to_errno(ret); 1176 if (ret) 1177 goto failed_addition; 1178 1179 /* 1180 * Fixup the number of isolated pageblocks before marking the sections 1181 * onlining, such that undo_isolate_page_range() works correctly. 1182 */ 1183 spin_lock_irqsave(&zone->lock, flags); 1184 zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages; 1185 spin_unlock_irqrestore(&zone->lock, flags); 1186 1187 /* 1188 * If this zone is not populated, then it is not in zonelist. 1189 * This means the page allocator ignores this zone. 1190 * So, zonelist must be updated after online. 1191 */ 1192 if (!populated_zone(zone)) { 1193 need_zonelists_rebuild = 1; 1194 setup_zone_pageset(zone); 1195 } 1196 1197 online_pages_range(pfn, nr_pages); 1198 adjust_present_page_count(pfn_to_page(pfn), group, nr_pages); 1199 1200 node_states_set_node(nid, &arg); 1201 if (need_zonelists_rebuild) 1202 build_all_zonelists(NULL); 1203 1204 /* Basic onlining is complete, allow allocation of onlined pages. */ 1205 undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE); 1206 1207 /* 1208 * Freshly onlined pages aren't shuffled (e.g., all pages are placed to 1209 * the tail of the freelist when undoing isolation). Shuffle the whole 1210 * zone to make sure the just onlined pages are properly distributed 1211 * across the whole freelist - to create an initial shuffle. 1212 */ 1213 shuffle_zone(zone); 1214 1215 /* reinitialise watermarks and update pcp limits */ 1216 init_per_zone_wmark_min(); 1217 1218 kswapd_run(nid); 1219 kcompactd_run(nid); 1220 1221 writeback_set_ratelimit(); 1222 1223 memory_notify(MEM_ONLINE, &arg); 1224 return 0; 1225 1226 failed_addition: 1227 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n", 1228 (unsigned long long) pfn << PAGE_SHIFT, 1229 (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1); 1230 memory_notify(MEM_CANCEL_ONLINE, &arg); 1231 remove_pfn_range_from_zone(zone, pfn, nr_pages); 1232 return ret; 1233 } 1234 1235 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ 1236 static pg_data_t *hotadd_init_pgdat(int nid) 1237 { 1238 struct pglist_data *pgdat; 1239 1240 /* 1241 * NODE_DATA is preallocated (free_area_init) but its internal 1242 * state is not allocated completely. Add missing pieces. 1243 * Completely offline nodes stay around and they just need 1244 * reintialization. 1245 */ 1246 pgdat = NODE_DATA(nid); 1247 1248 /* init node's zones as empty zones, we don't have any present pages.*/ 1249 free_area_init_core_hotplug(pgdat); 1250 1251 /* 1252 * The node we allocated has no zone fallback lists. For avoiding 1253 * to access not-initialized zonelist, build here. 1254 */ 1255 build_all_zonelists(pgdat); 1256 1257 return pgdat; 1258 } 1259 1260 /* 1261 * __try_online_node - online a node if offlined 1262 * @nid: the node ID 1263 * @set_node_online: Whether we want to online the node 1264 * called by cpu_up() to online a node without onlined memory. 1265 * 1266 * Returns: 1267 * 1 -> a new node has been allocated 1268 * 0 -> the node is already online 1269 * -ENOMEM -> the node could not be allocated 1270 */ 1271 static int __try_online_node(int nid, bool set_node_online) 1272 { 1273 pg_data_t *pgdat; 1274 int ret = 1; 1275 1276 if (node_online(nid)) 1277 return 0; 1278 1279 pgdat = hotadd_init_pgdat(nid); 1280 if (!pgdat) { 1281 pr_err("Cannot online node %d due to NULL pgdat\n", nid); 1282 ret = -ENOMEM; 1283 goto out; 1284 } 1285 1286 if (set_node_online) { 1287 node_set_online(nid); 1288 ret = register_one_node(nid); 1289 BUG_ON(ret); 1290 } 1291 out: 1292 return ret; 1293 } 1294 1295 /* 1296 * Users of this function always want to online/register the node 1297 */ 1298 int try_online_node(int nid) 1299 { 1300 int ret; 1301 1302 mem_hotplug_begin(); 1303 ret = __try_online_node(nid, true); 1304 mem_hotplug_done(); 1305 return ret; 1306 } 1307 1308 static int check_hotplug_memory_range(u64 start, u64 size) 1309 { 1310 /* memory range must be block size aligned */ 1311 if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) || 1312 !IS_ALIGNED(size, memory_block_size_bytes())) { 1313 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx", 1314 memory_block_size_bytes(), start, size); 1315 return -EINVAL; 1316 } 1317 1318 return 0; 1319 } 1320 1321 static int online_memory_block(struct memory_block *mem, void *arg) 1322 { 1323 mem->online_type = mhp_default_online_type; 1324 return device_online(&mem->dev); 1325 } 1326 1327 #ifndef arch_supports_memmap_on_memory 1328 static inline bool arch_supports_memmap_on_memory(unsigned long vmemmap_size) 1329 { 1330 /* 1331 * As default, we want the vmemmap to span a complete PMD such that we 1332 * can map the vmemmap using a single PMD if supported by the 1333 * architecture. 1334 */ 1335 return IS_ALIGNED(vmemmap_size, PMD_SIZE); 1336 } 1337 #endif 1338 1339 bool mhp_supports_memmap_on_memory(void) 1340 { 1341 unsigned long vmemmap_size = memory_block_memmap_size(); 1342 unsigned long memmap_pages = memory_block_memmap_on_memory_pages(); 1343 1344 /* 1345 * Besides having arch support and the feature enabled at runtime, we 1346 * need a few more assumptions to hold true: 1347 * 1348 * a) The vmemmap pages span complete PMDs: We don't want vmemmap code 1349 * to populate memory from the altmap for unrelated parts (i.e., 1350 * other memory blocks) 1351 * 1352 * b) The vmemmap pages (and thereby the pages that will be exposed to 1353 * the buddy) have to cover full pageblocks: memory onlining/offlining 1354 * code requires applicable ranges to be page-aligned, for example, to 1355 * set the migratetypes properly. 1356 * 1357 * TODO: Although we have a check here to make sure that vmemmap pages 1358 * fully populate a PMD, it is not the right place to check for 1359 * this. A much better solution involves improving vmemmap code 1360 * to fallback to base pages when trying to populate vmemmap using 1361 * altmap as an alternative source of memory, and we do not exactly 1362 * populate a single PMD. 1363 */ 1364 if (!mhp_memmap_on_memory()) 1365 return false; 1366 1367 /* 1368 * Make sure the vmemmap allocation is fully contained 1369 * so that we always allocate vmemmap memory from altmap area. 1370 */ 1371 if (!IS_ALIGNED(vmemmap_size, PAGE_SIZE)) 1372 return false; 1373 1374 /* 1375 * start pfn should be pageblock_nr_pages aligned for correctly 1376 * setting migrate types 1377 */ 1378 if (!pageblock_aligned(memmap_pages)) 1379 return false; 1380 1381 if (memmap_pages == PHYS_PFN(memory_block_size_bytes())) 1382 /* No effective hotplugged memory doesn't make sense. */ 1383 return false; 1384 1385 return arch_supports_memmap_on_memory(vmemmap_size); 1386 } 1387 EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory); 1388 1389 static void remove_memory_blocks_and_altmaps(u64 start, u64 size) 1390 { 1391 unsigned long memblock_size = memory_block_size_bytes(); 1392 u64 cur_start; 1393 1394 /* 1395 * For memmap_on_memory, the altmaps were added on a per-memblock 1396 * basis; we have to process each individual memory block. 1397 */ 1398 for (cur_start = start; cur_start < start + size; 1399 cur_start += memblock_size) { 1400 struct vmem_altmap *altmap = NULL; 1401 struct memory_block *mem; 1402 1403 mem = find_memory_block(pfn_to_section_nr(PFN_DOWN(cur_start))); 1404 if (WARN_ON_ONCE(!mem)) 1405 continue; 1406 1407 altmap = mem->altmap; 1408 mem->altmap = NULL; 1409 1410 remove_memory_block_devices(cur_start, memblock_size); 1411 1412 arch_remove_memory(cur_start, memblock_size, altmap); 1413 1414 /* Verify that all vmemmap pages have actually been freed. */ 1415 WARN(altmap->alloc, "Altmap not fully unmapped"); 1416 kfree(altmap); 1417 } 1418 } 1419 1420 static int create_altmaps_and_memory_blocks(int nid, struct memory_group *group, 1421 u64 start, u64 size, mhp_t mhp_flags) 1422 { 1423 unsigned long memblock_size = memory_block_size_bytes(); 1424 u64 cur_start; 1425 int ret; 1426 1427 for (cur_start = start; cur_start < start + size; 1428 cur_start += memblock_size) { 1429 struct mhp_params params = { .pgprot = 1430 pgprot_mhp(PAGE_KERNEL) }; 1431 struct vmem_altmap mhp_altmap = { 1432 .base_pfn = PHYS_PFN(cur_start), 1433 .end_pfn = PHYS_PFN(cur_start + memblock_size - 1), 1434 }; 1435 1436 mhp_altmap.free = memory_block_memmap_on_memory_pages(); 1437 if (mhp_flags & MHP_OFFLINE_INACCESSIBLE) 1438 mhp_altmap.inaccessible = true; 1439 params.altmap = kmemdup(&mhp_altmap, sizeof(struct vmem_altmap), 1440 GFP_KERNEL); 1441 if (!params.altmap) { 1442 ret = -ENOMEM; 1443 goto out; 1444 } 1445 1446 /* call arch's memory hotadd */ 1447 ret = arch_add_memory(nid, cur_start, memblock_size, ¶ms); 1448 if (ret < 0) { 1449 kfree(params.altmap); 1450 goto out; 1451 } 1452 1453 /* create memory block devices after memory was added */ 1454 ret = create_memory_block_devices(cur_start, memblock_size, 1455 params.altmap, group); 1456 if (ret) { 1457 arch_remove_memory(cur_start, memblock_size, NULL); 1458 kfree(params.altmap); 1459 goto out; 1460 } 1461 } 1462 1463 return 0; 1464 out: 1465 if (ret && cur_start != start) 1466 remove_memory_blocks_and_altmaps(start, cur_start - start); 1467 return ret; 1468 } 1469 1470 /* 1471 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 1472 * and online/offline operations (triggered e.g. by sysfs). 1473 * 1474 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG 1475 */ 1476 int add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) 1477 { 1478 struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; 1479 enum memblock_flags memblock_flags = MEMBLOCK_NONE; 1480 struct memory_group *group = NULL; 1481 u64 start, size; 1482 bool new_node = false; 1483 int ret; 1484 1485 start = res->start; 1486 size = resource_size(res); 1487 1488 ret = check_hotplug_memory_range(start, size); 1489 if (ret) 1490 return ret; 1491 1492 if (mhp_flags & MHP_NID_IS_MGID) { 1493 group = memory_group_find_by_id(nid); 1494 if (!group) 1495 return -EINVAL; 1496 nid = group->nid; 1497 } 1498 1499 if (!node_possible(nid)) { 1500 WARN(1, "node %d was absent from the node_possible_map\n", nid); 1501 return -EINVAL; 1502 } 1503 1504 mem_hotplug_begin(); 1505 1506 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { 1507 if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED) 1508 memblock_flags = MEMBLOCK_DRIVER_MANAGED; 1509 ret = memblock_add_node(start, size, nid, memblock_flags); 1510 if (ret) 1511 goto error_mem_hotplug_end; 1512 } 1513 1514 ret = __try_online_node(nid, false); 1515 if (ret < 0) 1516 goto error; 1517 new_node = ret; 1518 1519 /* 1520 * Self hosted memmap array 1521 */ 1522 if ((mhp_flags & MHP_MEMMAP_ON_MEMORY) && 1523 mhp_supports_memmap_on_memory()) { 1524 ret = create_altmaps_and_memory_blocks(nid, group, start, size, mhp_flags); 1525 if (ret) 1526 goto error; 1527 } else { 1528 ret = arch_add_memory(nid, start, size, ¶ms); 1529 if (ret < 0) 1530 goto error; 1531 1532 /* create memory block devices after memory was added */ 1533 ret = create_memory_block_devices(start, size, NULL, group); 1534 if (ret) { 1535 arch_remove_memory(start, size, params.altmap); 1536 goto error; 1537 } 1538 } 1539 1540 if (new_node) { 1541 /* If sysfs file of new node can't be created, cpu on the node 1542 * can't be hot-added. There is no rollback way now. 1543 * So, check by BUG_ON() to catch it reluctantly.. 1544 * We online node here. We can't roll back from here. 1545 */ 1546 node_set_online(nid); 1547 ret = __register_one_node(nid); 1548 BUG_ON(ret); 1549 } 1550 1551 register_memory_blocks_under_node(nid, PFN_DOWN(start), 1552 PFN_UP(start + size - 1), 1553 MEMINIT_HOTPLUG); 1554 1555 /* create new memmap entry */ 1556 if (!strcmp(res->name, "System RAM")) 1557 firmware_map_add_hotplug(start, start + size, "System RAM"); 1558 1559 /* device_online() will take the lock when calling online_pages() */ 1560 mem_hotplug_done(); 1561 1562 /* 1563 * In case we're allowed to merge the resource, flag it and trigger 1564 * merging now that adding succeeded. 1565 */ 1566 if (mhp_flags & MHP_MERGE_RESOURCE) 1567 merge_system_ram_resource(res); 1568 1569 /* online pages if requested */ 1570 if (mhp_default_online_type != MMOP_OFFLINE) 1571 walk_memory_blocks(start, size, NULL, online_memory_block); 1572 1573 return ret; 1574 error: 1575 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) 1576 memblock_remove(start, size); 1577 error_mem_hotplug_end: 1578 mem_hotplug_done(); 1579 return ret; 1580 } 1581 1582 /* requires device_hotplug_lock, see add_memory_resource() */ 1583 int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) 1584 { 1585 struct resource *res; 1586 int ret; 1587 1588 res = register_memory_resource(start, size, "System RAM"); 1589 if (IS_ERR(res)) 1590 return PTR_ERR(res); 1591 1592 ret = add_memory_resource(nid, res, mhp_flags); 1593 if (ret < 0) 1594 release_memory_resource(res); 1595 return ret; 1596 } 1597 1598 int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) 1599 { 1600 int rc; 1601 1602 lock_device_hotplug(); 1603 rc = __add_memory(nid, start, size, mhp_flags); 1604 unlock_device_hotplug(); 1605 1606 return rc; 1607 } 1608 EXPORT_SYMBOL_GPL(add_memory); 1609 1610 /* 1611 * Add special, driver-managed memory to the system as system RAM. Such 1612 * memory is not exposed via the raw firmware-provided memmap as system 1613 * RAM, instead, it is detected and added by a driver - during cold boot, 1614 * after a reboot, and after kexec. 1615 * 1616 * Reasons why this memory should not be used for the initial memmap of a 1617 * kexec kernel or for placing kexec images: 1618 * - The booting kernel is in charge of determining how this memory will be 1619 * used (e.g., use persistent memory as system RAM) 1620 * - Coordination with a hypervisor is required before this memory 1621 * can be used (e.g., inaccessible parts). 1622 * 1623 * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided 1624 * memory map") are created. Also, the created memory resource is flagged 1625 * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case 1626 * this memory as well (esp., not place kexec images onto it). 1627 * 1628 * The resource_name (visible via /proc/iomem) has to have the format 1629 * "System RAM ($DRIVER)". 1630 */ 1631 int add_memory_driver_managed(int nid, u64 start, u64 size, 1632 const char *resource_name, mhp_t mhp_flags) 1633 { 1634 struct resource *res; 1635 int rc; 1636 1637 if (!resource_name || 1638 strstr(resource_name, "System RAM (") != resource_name || 1639 resource_name[strlen(resource_name) - 1] != ')') 1640 return -EINVAL; 1641 1642 lock_device_hotplug(); 1643 1644 res = register_memory_resource(start, size, resource_name); 1645 if (IS_ERR(res)) { 1646 rc = PTR_ERR(res); 1647 goto out_unlock; 1648 } 1649 1650 rc = add_memory_resource(nid, res, mhp_flags); 1651 if (rc < 0) 1652 release_memory_resource(res); 1653 1654 out_unlock: 1655 unlock_device_hotplug(); 1656 return rc; 1657 } 1658 EXPORT_SYMBOL_GPL(add_memory_driver_managed); 1659 1660 /* 1661 * Platforms should define arch_get_mappable_range() that provides 1662 * maximum possible addressable physical memory range for which the 1663 * linear mapping could be created. The platform returned address 1664 * range must adhere to these following semantics. 1665 * 1666 * - range.start <= range.end 1667 * - Range includes both end points [range.start..range.end] 1668 * 1669 * There is also a fallback definition provided here, allowing the 1670 * entire possible physical address range in case any platform does 1671 * not define arch_get_mappable_range(). 1672 */ 1673 struct range __weak arch_get_mappable_range(void) 1674 { 1675 struct range mhp_range = { 1676 .start = 0UL, 1677 .end = -1ULL, 1678 }; 1679 return mhp_range; 1680 } 1681 1682 struct range mhp_get_pluggable_range(bool need_mapping) 1683 { 1684 const u64 max_phys = DIRECT_MAP_PHYSMEM_END; 1685 struct range mhp_range; 1686 1687 if (need_mapping) { 1688 mhp_range = arch_get_mappable_range(); 1689 if (mhp_range.start > max_phys) { 1690 mhp_range.start = 0; 1691 mhp_range.end = 0; 1692 } 1693 mhp_range.end = min_t(u64, mhp_range.end, max_phys); 1694 } else { 1695 mhp_range.start = 0; 1696 mhp_range.end = max_phys; 1697 } 1698 return mhp_range; 1699 } 1700 EXPORT_SYMBOL_GPL(mhp_get_pluggable_range); 1701 1702 bool mhp_range_allowed(u64 start, u64 size, bool need_mapping) 1703 { 1704 struct range mhp_range = mhp_get_pluggable_range(need_mapping); 1705 u64 end = start + size; 1706 1707 if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end) 1708 return true; 1709 1710 pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n", 1711 start, end, mhp_range.start, mhp_range.end); 1712 return false; 1713 } 1714 1715 #ifdef CONFIG_MEMORY_HOTREMOVE 1716 /* 1717 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages, 1718 * non-lru movable pages and hugepages). Will skip over most unmovable 1719 * pages (esp., pages that can be skipped when offlining), but bail out on 1720 * definitely unmovable pages. 1721 * 1722 * Returns: 1723 * 0 in case a movable page is found and movable_pfn was updated. 1724 * -ENOENT in case no movable page was found. 1725 * -EBUSY in case a definitely unmovable page was found. 1726 */ 1727 static int scan_movable_pages(unsigned long start, unsigned long end, 1728 unsigned long *movable_pfn) 1729 { 1730 unsigned long pfn; 1731 1732 for (pfn = start; pfn < end; pfn++) { 1733 struct page *page; 1734 struct folio *folio; 1735 1736 if (!pfn_valid(pfn)) 1737 continue; 1738 page = pfn_to_page(pfn); 1739 if (PageLRU(page)) 1740 goto found; 1741 if (__PageMovable(page)) 1742 goto found; 1743 1744 /* 1745 * PageOffline() pages that are not marked __PageMovable() and 1746 * have a reference count > 0 (after MEM_GOING_OFFLINE) are 1747 * definitely unmovable. If their reference count would be 0, 1748 * they could at least be skipped when offlining memory. 1749 */ 1750 if (PageOffline(page) && page_count(page)) 1751 return -EBUSY; 1752 1753 if (!PageHuge(page)) 1754 continue; 1755 folio = page_folio(page); 1756 /* 1757 * This test is racy as we hold no reference or lock. The 1758 * hugetlb page could have been free'ed and head is no longer 1759 * a hugetlb page before the following check. In such unlikely 1760 * cases false positives and negatives are possible. Calling 1761 * code must deal with these scenarios. 1762 */ 1763 if (folio_test_hugetlb_migratable(folio)) 1764 goto found; 1765 pfn |= folio_nr_pages(folio) - 1; 1766 } 1767 return -ENOENT; 1768 found: 1769 *movable_pfn = pfn; 1770 return 0; 1771 } 1772 1773 static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) 1774 { 1775 struct folio *folio; 1776 unsigned long pfn; 1777 LIST_HEAD(source); 1778 static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL, 1779 DEFAULT_RATELIMIT_BURST); 1780 1781 for (pfn = start_pfn; pfn < end_pfn; pfn++) { 1782 struct page *page; 1783 1784 if (!pfn_valid(pfn)) 1785 continue; 1786 page = pfn_to_page(pfn); 1787 folio = page_folio(page); 1788 1789 /* 1790 * No reference or lock is held on the folio, so it might 1791 * be modified concurrently (e.g. split). As such, 1792 * folio_nr_pages() may read garbage. This is fine as the outer 1793 * loop will revisit the split folio later. 1794 */ 1795 if (folio_test_large(folio)) 1796 pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1; 1797 1798 /* 1799 * HWPoison pages have elevated reference counts so the migration would 1800 * fail on them. It also doesn't make any sense to migrate them in the 1801 * first place. Still try to unmap such a page in case it is still mapped 1802 * (keep the unmap as the catch all safety net). 1803 */ 1804 if (folio_test_hwpoison(folio) || 1805 (folio_test_large(folio) && folio_test_has_hwpoisoned(folio))) { 1806 if (WARN_ON(folio_test_lru(folio))) 1807 folio_isolate_lru(folio); 1808 if (folio_mapped(folio)) 1809 unmap_poisoned_folio(folio, TTU_IGNORE_MLOCK); 1810 continue; 1811 } 1812 1813 if (!folio_try_get(folio)) 1814 continue; 1815 1816 if (unlikely(page_folio(page) != folio)) 1817 goto put_folio; 1818 1819 if (!isolate_folio_to_list(folio, &source)) { 1820 if (__ratelimit(&migrate_rs)) { 1821 pr_warn("failed to isolate pfn %lx\n", 1822 page_to_pfn(page)); 1823 dump_page(page, "isolation failed"); 1824 } 1825 } 1826 put_folio: 1827 folio_put(folio); 1828 } 1829 if (!list_empty(&source)) { 1830 nodemask_t nmask = node_states[N_MEMORY]; 1831 struct migration_target_control mtc = { 1832 .nmask = &nmask, 1833 .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, 1834 .reason = MR_MEMORY_HOTPLUG, 1835 }; 1836 int ret; 1837 1838 /* 1839 * We have checked that migration range is on a single zone so 1840 * we can use the nid of the first page to all the others. 1841 */ 1842 mtc.nid = folio_nid(list_first_entry(&source, struct folio, lru)); 1843 1844 /* 1845 * try to allocate from a different node but reuse this node 1846 * if there are no other online nodes to be used (e.g. we are 1847 * offlining a part of the only existing node) 1848 */ 1849 node_clear(mtc.nid, nmask); 1850 if (nodes_empty(nmask)) 1851 node_set(mtc.nid, nmask); 1852 ret = migrate_pages(&source, alloc_migration_target, NULL, 1853 (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL); 1854 if (ret) { 1855 list_for_each_entry(folio, &source, lru) { 1856 if (__ratelimit(&migrate_rs)) { 1857 pr_warn("migrating pfn %lx failed ret:%d\n", 1858 folio_pfn(folio), ret); 1859 dump_page(&folio->page, 1860 "migration failure"); 1861 } 1862 } 1863 putback_movable_pages(&source); 1864 } 1865 } 1866 } 1867 1868 static int __init cmdline_parse_movable_node(char *p) 1869 { 1870 movable_node_enabled = true; 1871 return 0; 1872 } 1873 early_param("movable_node", cmdline_parse_movable_node); 1874 1875 /* check which state of node_states will be changed when offline memory */ 1876 static void node_states_check_changes_offline(unsigned long nr_pages, 1877 struct zone *zone, struct memory_notify *arg) 1878 { 1879 struct pglist_data *pgdat = zone->zone_pgdat; 1880 unsigned long present_pages = 0; 1881 enum zone_type zt; 1882 1883 arg->status_change_nid = NUMA_NO_NODE; 1884 arg->status_change_nid_normal = NUMA_NO_NODE; 1885 1886 /* 1887 * Check whether node_states[N_NORMAL_MEMORY] will be changed. 1888 * If the memory to be offline is within the range 1889 * [0..ZONE_NORMAL], and it is the last present memory there, 1890 * the zones in that range will become empty after the offlining, 1891 * thus we can determine that we need to clear the node from 1892 * node_states[N_NORMAL_MEMORY]. 1893 */ 1894 for (zt = 0; zt <= ZONE_NORMAL; zt++) 1895 present_pages += pgdat->node_zones[zt].present_pages; 1896 if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages) 1897 arg->status_change_nid_normal = zone_to_nid(zone); 1898 1899 /* 1900 * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM 1901 * does not apply as we don't support 32bit. 1902 * Here we count the possible pages from ZONE_MOVABLE. 1903 * If after having accounted all the pages, we see that the nr_pages 1904 * to be offlined is over or equal to the accounted pages, 1905 * we know that the node will become empty, and so, we can clear 1906 * it for N_MEMORY as well. 1907 */ 1908 present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages; 1909 1910 if (nr_pages >= present_pages) 1911 arg->status_change_nid = zone_to_nid(zone); 1912 } 1913 1914 static void node_states_clear_node(int node, struct memory_notify *arg) 1915 { 1916 if (arg->status_change_nid_normal >= 0) 1917 node_clear_state(node, N_NORMAL_MEMORY); 1918 1919 if (arg->status_change_nid >= 0) 1920 node_clear_state(node, N_MEMORY); 1921 } 1922 1923 static int count_system_ram_pages_cb(unsigned long start_pfn, 1924 unsigned long nr_pages, void *data) 1925 { 1926 unsigned long *nr_system_ram_pages = data; 1927 1928 *nr_system_ram_pages += nr_pages; 1929 return 0; 1930 } 1931 1932 /* 1933 * Must be called with mem_hotplug_lock in write mode. 1934 */ 1935 int offline_pages(unsigned long start_pfn, unsigned long nr_pages, 1936 struct zone *zone, struct memory_group *group) 1937 { 1938 const unsigned long end_pfn = start_pfn + nr_pages; 1939 unsigned long pfn, managed_pages, system_ram_pages = 0; 1940 const int node = zone_to_nid(zone); 1941 unsigned long flags; 1942 struct memory_notify arg; 1943 char *reason; 1944 int ret; 1945 1946 /* 1947 * {on,off}lining is constrained to full memory sections (or more 1948 * precisely to memory blocks from the user space POV). 1949 * memmap_on_memory is an exception because it reserves initial part 1950 * of the physical memory space for vmemmaps. That space is pageblock 1951 * aligned. 1952 */ 1953 if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) || 1954 !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))) 1955 return -EINVAL; 1956 1957 /* 1958 * Don't allow to offline memory blocks that contain holes. 1959 * Consequently, memory blocks with holes can never get onlined 1960 * via the hotplug path - online_pages() - as hotplugged memory has 1961 * no holes. This way, we don't have to worry about memory holes, 1962 * don't need pfn_valid() checks, and can avoid using 1963 * walk_system_ram_range() later. 1964 */ 1965 walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages, 1966 count_system_ram_pages_cb); 1967 if (system_ram_pages != nr_pages) { 1968 ret = -EINVAL; 1969 reason = "memory holes"; 1970 goto failed_removal; 1971 } 1972 1973 /* 1974 * We only support offlining of memory blocks managed by a single zone, 1975 * checked by calling code. This is just a sanity check that we might 1976 * want to remove in the future. 1977 */ 1978 if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn)) != zone || 1979 page_zone(pfn_to_page(end_pfn - 1)) != zone)) { 1980 ret = -EINVAL; 1981 reason = "multizone range"; 1982 goto failed_removal; 1983 } 1984 1985 /* 1986 * Disable pcplists so that page isolation cannot race with freeing 1987 * in a way that pages from isolated pageblock are left on pcplists. 1988 */ 1989 zone_pcp_disable(zone); 1990 lru_cache_disable(); 1991 1992 /* set above range as isolated */ 1993 ret = start_isolate_page_range(start_pfn, end_pfn, 1994 MIGRATE_MOVABLE, 1995 MEMORY_OFFLINE | REPORT_FAILURE, 1996 GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL); 1997 if (ret) { 1998 reason = "failure to isolate range"; 1999 goto failed_removal_pcplists_disabled; 2000 } 2001 2002 arg.start_pfn = start_pfn; 2003 arg.nr_pages = nr_pages; 2004 node_states_check_changes_offline(nr_pages, zone, &arg); 2005 2006 ret = memory_notify(MEM_GOING_OFFLINE, &arg); 2007 ret = notifier_to_errno(ret); 2008 if (ret) { 2009 reason = "notifier failure"; 2010 goto failed_removal_isolated; 2011 } 2012 2013 do { 2014 pfn = start_pfn; 2015 do { 2016 /* 2017 * Historically we always checked for any signal and 2018 * can't limit it to fatal signals without eventually 2019 * breaking user space. 2020 */ 2021 if (signal_pending(current)) { 2022 ret = -EINTR; 2023 reason = "signal backoff"; 2024 goto failed_removal_isolated; 2025 } 2026 2027 cond_resched(); 2028 2029 ret = scan_movable_pages(pfn, end_pfn, &pfn); 2030 if (!ret) { 2031 /* 2032 * TODO: fatal migration failures should bail 2033 * out 2034 */ 2035 do_migrate_range(pfn, end_pfn); 2036 } 2037 } while (!ret); 2038 2039 if (ret != -ENOENT) { 2040 reason = "unmovable page"; 2041 goto failed_removal_isolated; 2042 } 2043 2044 /* 2045 * Dissolve free hugetlb folios in the memory block before doing 2046 * offlining actually in order to make hugetlbfs's object 2047 * counting consistent. 2048 */ 2049 ret = dissolve_free_hugetlb_folios(start_pfn, end_pfn); 2050 if (ret) { 2051 reason = "failure to dissolve huge pages"; 2052 goto failed_removal_isolated; 2053 } 2054 2055 ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE); 2056 2057 } while (ret); 2058 2059 /* Mark all sections offline and remove free pages from the buddy. */ 2060 managed_pages = __offline_isolated_pages(start_pfn, end_pfn); 2061 pr_debug("Offlined Pages %ld\n", nr_pages); 2062 2063 /* 2064 * The memory sections are marked offline, and the pageblock flags 2065 * effectively stale; nobody should be touching them. Fixup the number 2066 * of isolated pageblocks, memory onlining will properly revert this. 2067 */ 2068 spin_lock_irqsave(&zone->lock, flags); 2069 zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages; 2070 spin_unlock_irqrestore(&zone->lock, flags); 2071 2072 lru_cache_enable(); 2073 zone_pcp_enable(zone); 2074 2075 /* removal success */ 2076 adjust_managed_page_count(pfn_to_page(start_pfn), -managed_pages); 2077 adjust_present_page_count(pfn_to_page(start_pfn), group, -nr_pages); 2078 2079 /* reinitialise watermarks and update pcp limits */ 2080 init_per_zone_wmark_min(); 2081 2082 /* 2083 * Make sure to mark the node as memory-less before rebuilding the zone 2084 * list. Otherwise this node would still appear in the fallback lists. 2085 */ 2086 node_states_clear_node(node, &arg); 2087 if (!populated_zone(zone)) { 2088 zone_pcp_reset(zone); 2089 build_all_zonelists(NULL); 2090 } 2091 2092 if (arg.status_change_nid >= 0) { 2093 kcompactd_stop(node); 2094 kswapd_stop(node); 2095 } 2096 2097 writeback_set_ratelimit(); 2098 2099 memory_notify(MEM_OFFLINE, &arg); 2100 remove_pfn_range_from_zone(zone, start_pfn, nr_pages); 2101 return 0; 2102 2103 failed_removal_isolated: 2104 /* pushback to free area */ 2105 undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); 2106 memory_notify(MEM_CANCEL_OFFLINE, &arg); 2107 failed_removal_pcplists_disabled: 2108 lru_cache_enable(); 2109 zone_pcp_enable(zone); 2110 failed_removal: 2111 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n", 2112 (unsigned long long) start_pfn << PAGE_SHIFT, 2113 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1, 2114 reason); 2115 return ret; 2116 } 2117 2118 static int check_memblock_offlined_cb(struct memory_block *mem, void *arg) 2119 { 2120 int *nid = arg; 2121 2122 *nid = mem->nid; 2123 if (unlikely(mem->state != MEM_OFFLINE)) { 2124 phys_addr_t beginpa, endpa; 2125 2126 beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)); 2127 endpa = beginpa + memory_block_size_bytes() - 1; 2128 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n", 2129 &beginpa, &endpa); 2130 2131 return -EBUSY; 2132 } 2133 return 0; 2134 } 2135 2136 static int count_memory_range_altmaps_cb(struct memory_block *mem, void *arg) 2137 { 2138 u64 *num_altmaps = (u64 *)arg; 2139 2140 if (mem->altmap) 2141 *num_altmaps += 1; 2142 2143 return 0; 2144 } 2145 2146 static int check_cpu_on_node(int nid) 2147 { 2148 int cpu; 2149 2150 for_each_present_cpu(cpu) { 2151 if (cpu_to_node(cpu) == nid) 2152 /* 2153 * the cpu on this node isn't removed, and we can't 2154 * offline this node. 2155 */ 2156 return -EBUSY; 2157 } 2158 2159 return 0; 2160 } 2161 2162 static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg) 2163 { 2164 int nid = *(int *)arg; 2165 2166 /* 2167 * If a memory block belongs to multiple nodes, the stored nid is not 2168 * reliable. However, such blocks are always online (e.g., cannot get 2169 * offlined) and, therefore, are still spanned by the node. 2170 */ 2171 return mem->nid == nid ? -EEXIST : 0; 2172 } 2173 2174 /** 2175 * try_offline_node 2176 * @nid: the node ID 2177 * 2178 * Offline a node if all memory sections and cpus of the node are removed. 2179 * 2180 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 2181 * and online/offline operations before this call. 2182 */ 2183 void try_offline_node(int nid) 2184 { 2185 int rc; 2186 2187 /* 2188 * If the node still spans pages (especially ZONE_DEVICE), don't 2189 * offline it. A node spans memory after move_pfn_range_to_zone(), 2190 * e.g., after the memory block was onlined. 2191 */ 2192 if (node_spanned_pages(nid)) 2193 return; 2194 2195 /* 2196 * Especially offline memory blocks might not be spanned by the 2197 * node. They will get spanned by the node once they get onlined. 2198 * However, they link to the node in sysfs and can get onlined later. 2199 */ 2200 rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb); 2201 if (rc) 2202 return; 2203 2204 if (check_cpu_on_node(nid)) 2205 return; 2206 2207 /* 2208 * all memory/cpu of this node are removed, we can offline this 2209 * node now. 2210 */ 2211 node_set_offline(nid); 2212 unregister_one_node(nid); 2213 } 2214 EXPORT_SYMBOL(try_offline_node); 2215 2216 static int memory_blocks_have_altmaps(u64 start, u64 size) 2217 { 2218 u64 num_memblocks = size / memory_block_size_bytes(); 2219 u64 num_altmaps = 0; 2220 2221 if (!mhp_memmap_on_memory()) 2222 return 0; 2223 2224 walk_memory_blocks(start, size, &num_altmaps, 2225 count_memory_range_altmaps_cb); 2226 2227 if (num_altmaps == 0) 2228 return 0; 2229 2230 if (WARN_ON_ONCE(num_memblocks != num_altmaps)) 2231 return -EINVAL; 2232 2233 return 1; 2234 } 2235 2236 static int try_remove_memory(u64 start, u64 size) 2237 { 2238 int rc, nid = NUMA_NO_NODE; 2239 2240 BUG_ON(check_hotplug_memory_range(start, size)); 2241 2242 /* 2243 * All memory blocks must be offlined before removing memory. Check 2244 * whether all memory blocks in question are offline and return error 2245 * if this is not the case. 2246 * 2247 * While at it, determine the nid. Note that if we'd have mixed nodes, 2248 * we'd only try to offline the last determined one -- which is good 2249 * enough for the cases we care about. 2250 */ 2251 rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb); 2252 if (rc) 2253 return rc; 2254 2255 /* remove memmap entry */ 2256 firmware_map_remove(start, start + size, "System RAM"); 2257 2258 mem_hotplug_begin(); 2259 2260 rc = memory_blocks_have_altmaps(start, size); 2261 if (rc < 0) { 2262 mem_hotplug_done(); 2263 return rc; 2264 } else if (!rc) { 2265 /* 2266 * Memory block device removal under the device_hotplug_lock is 2267 * a barrier against racing online attempts. 2268 * No altmaps present, do the removal directly 2269 */ 2270 remove_memory_block_devices(start, size); 2271 arch_remove_memory(start, size, NULL); 2272 } else { 2273 /* all memblocks in the range have altmaps */ 2274 remove_memory_blocks_and_altmaps(start, size); 2275 } 2276 2277 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) 2278 memblock_remove(start, size); 2279 2280 release_mem_region_adjustable(start, size); 2281 2282 if (nid != NUMA_NO_NODE) 2283 try_offline_node(nid); 2284 2285 mem_hotplug_done(); 2286 return 0; 2287 } 2288 2289 /** 2290 * __remove_memory - Remove memory if every memory block is offline 2291 * @start: physical address of the region to remove 2292 * @size: size of the region to remove 2293 * 2294 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug 2295 * and online/offline operations before this call, as required by 2296 * try_offline_node(). 2297 */ 2298 void __remove_memory(u64 start, u64 size) 2299 { 2300 2301 /* 2302 * trigger BUG() if some memory is not offlined prior to calling this 2303 * function 2304 */ 2305 if (try_remove_memory(start, size)) 2306 BUG(); 2307 } 2308 2309 /* 2310 * Remove memory if every memory block is offline, otherwise return -EBUSY is 2311 * some memory is not offline 2312 */ 2313 int remove_memory(u64 start, u64 size) 2314 { 2315 int rc; 2316 2317 lock_device_hotplug(); 2318 rc = try_remove_memory(start, size); 2319 unlock_device_hotplug(); 2320 2321 return rc; 2322 } 2323 EXPORT_SYMBOL_GPL(remove_memory); 2324 2325 static int try_offline_memory_block(struct memory_block *mem, void *arg) 2326 { 2327 uint8_t online_type = MMOP_ONLINE_KERNEL; 2328 uint8_t **online_types = arg; 2329 struct page *page; 2330 int rc; 2331 2332 /* 2333 * Sense the online_type via the zone of the memory block. Offlining 2334 * with multiple zones within one memory block will be rejected 2335 * by offlining code ... so we don't care about that. 2336 */ 2337 page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr)); 2338 if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE) 2339 online_type = MMOP_ONLINE_MOVABLE; 2340 2341 rc = device_offline(&mem->dev); 2342 /* 2343 * Default is MMOP_OFFLINE - change it only if offlining succeeded, 2344 * so try_reonline_memory_block() can do the right thing. 2345 */ 2346 if (!rc) 2347 **online_types = online_type; 2348 2349 (*online_types)++; 2350 /* Ignore if already offline. */ 2351 return rc < 0 ? rc : 0; 2352 } 2353 2354 static int try_reonline_memory_block(struct memory_block *mem, void *arg) 2355 { 2356 uint8_t **online_types = arg; 2357 int rc; 2358 2359 if (**online_types != MMOP_OFFLINE) { 2360 mem->online_type = **online_types; 2361 rc = device_online(&mem->dev); 2362 if (rc < 0) 2363 pr_warn("%s: Failed to re-online memory: %d", 2364 __func__, rc); 2365 } 2366 2367 /* Continue processing all remaining memory blocks. */ 2368 (*online_types)++; 2369 return 0; 2370 } 2371 2372 /* 2373 * Try to offline and remove memory. Might take a long time to finish in case 2374 * memory is still in use. Primarily useful for memory devices that logically 2375 * unplugged all memory (so it's no longer in use) and want to offline + remove 2376 * that memory. 2377 */ 2378 int offline_and_remove_memory(u64 start, u64 size) 2379 { 2380 const unsigned long mb_count = size / memory_block_size_bytes(); 2381 uint8_t *online_types, *tmp; 2382 int rc; 2383 2384 if (!IS_ALIGNED(start, memory_block_size_bytes()) || 2385 !IS_ALIGNED(size, memory_block_size_bytes()) || !size) 2386 return -EINVAL; 2387 2388 /* 2389 * We'll remember the old online type of each memory block, so we can 2390 * try to revert whatever we did when offlining one memory block fails 2391 * after offlining some others succeeded. 2392 */ 2393 online_types = kmalloc_array(mb_count, sizeof(*online_types), 2394 GFP_KERNEL); 2395 if (!online_types) 2396 return -ENOMEM; 2397 /* 2398 * Initialize all states to MMOP_OFFLINE, so when we abort processing in 2399 * try_offline_memory_block(), we'll skip all unprocessed blocks in 2400 * try_reonline_memory_block(). 2401 */ 2402 memset(online_types, MMOP_OFFLINE, mb_count); 2403 2404 lock_device_hotplug(); 2405 2406 tmp = online_types; 2407 rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block); 2408 2409 /* 2410 * In case we succeeded to offline all memory, remove it. 2411 * This cannot fail as it cannot get onlined in the meantime. 2412 */ 2413 if (!rc) { 2414 rc = try_remove_memory(start, size); 2415 if (rc) 2416 pr_err("%s: Failed to remove memory: %d", __func__, rc); 2417 } 2418 2419 /* 2420 * Rollback what we did. While memory onlining might theoretically fail 2421 * (nacked by a notifier), it barely ever happens. 2422 */ 2423 if (rc) { 2424 tmp = online_types; 2425 walk_memory_blocks(start, size, &tmp, 2426 try_reonline_memory_block); 2427 } 2428 unlock_device_hotplug(); 2429 2430 kfree(online_types); 2431 return rc; 2432 } 2433 EXPORT_SYMBOL_GPL(offline_and_remove_memory); 2434 #endif /* CONFIG_MEMORY_HOTREMOVE */ 2435