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