1// SPDX-License-Identifier: GPL-2.0 2#include <linux/debugfs.h> 3#include <linux/mm.h> 4#include <linux/slab.h> 5#include <linux/uaccess.h> 6#include <linux/memblock.h> 7#include <linux/stacktrace.h> 8#include <linux/page_owner.h> 9#include <linux/jump_label.h> 10#include <linux/migrate.h> 11#include <linux/stackdepot.h> 12#include <linux/seq_file.h> 13#include <linux/memcontrol.h> 14#include <linux/sched/clock.h> 15 16#include "internal.h" 17 18/* 19 * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack) 20 * to use off stack temporal storage 21 */ 22#define PAGE_OWNER_STACK_DEPTH (16) 23 24struct page_owner { 25 unsigned short order; 26 short last_migrate_reason; 27 gfp_t gfp_mask; 28 depot_stack_handle_t handle; 29 depot_stack_handle_t free_handle; 30 u64 ts_nsec; 31 u64 free_ts_nsec; 32 char comm[TASK_COMM_LEN]; 33 pid_t pid; 34 pid_t tgid; 35 pid_t free_pid; 36 pid_t free_tgid; 37}; 38 39struct stack { 40 struct stack_record *stack_record; 41 struct stack *next; 42}; 43static struct stack dummy_stack; 44static struct stack failure_stack; 45static struct stack *stack_list; 46static DEFINE_SPINLOCK(stack_list_lock); 47 48static bool page_owner_enabled __initdata; 49DEFINE_STATIC_KEY_FALSE(page_owner_inited); 50 51static depot_stack_handle_t dummy_handle; 52static depot_stack_handle_t failure_handle; 53static depot_stack_handle_t early_handle; 54 55static void init_early_allocated_pages(void); 56 57static inline void set_current_in_page_owner(void) 58{ 59 /* 60 * Avoid recursion. 61 * 62 * We might need to allocate more memory from page_owner code, so make 63 * sure to signal it in order to avoid recursion. 64 */ 65 current->in_page_owner = 1; 66} 67 68static inline void unset_current_in_page_owner(void) 69{ 70 current->in_page_owner = 0; 71} 72 73static int __init early_page_owner_param(char *buf) 74{ 75 int ret = kstrtobool(buf, &page_owner_enabled); 76 77 if (page_owner_enabled) 78 stack_depot_request_early_init(); 79 80 return ret; 81} 82early_param("page_owner", early_page_owner_param); 83 84static __init bool need_page_owner(void) 85{ 86 return page_owner_enabled; 87} 88 89static __always_inline depot_stack_handle_t create_dummy_stack(void) 90{ 91 unsigned long entries[4]; 92 unsigned int nr_entries; 93 94 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0); 95 return stack_depot_save(entries, nr_entries, GFP_KERNEL); 96} 97 98static noinline void register_dummy_stack(void) 99{ 100 dummy_handle = create_dummy_stack(); 101} 102 103static noinline void register_failure_stack(void) 104{ 105 failure_handle = create_dummy_stack(); 106} 107 108static noinline void register_early_stack(void) 109{ 110 early_handle = create_dummy_stack(); 111} 112 113static __init void init_page_owner(void) 114{ 115 if (!page_owner_enabled) 116 return; 117 118 register_dummy_stack(); 119 register_failure_stack(); 120 register_early_stack(); 121 init_early_allocated_pages(); 122 /* Initialize dummy and failure stacks and link them to stack_list */ 123 dummy_stack.stack_record = __stack_depot_get_stack_record(dummy_handle); 124 failure_stack.stack_record = __stack_depot_get_stack_record(failure_handle); 125 if (dummy_stack.stack_record) 126 refcount_set(&dummy_stack.stack_record->count, 1); 127 if (failure_stack.stack_record) 128 refcount_set(&failure_stack.stack_record->count, 1); 129 dummy_stack.next = &failure_stack; 130 stack_list = &dummy_stack; 131 static_branch_enable(&page_owner_inited); 132} 133 134struct page_ext_operations page_owner_ops = { 135 .size = sizeof(struct page_owner), 136 .need = need_page_owner, 137 .init = init_page_owner, 138 .need_shared_flags = true, 139}; 140 141static inline struct page_owner *get_page_owner(struct page_ext *page_ext) 142{ 143 return page_ext_data(page_ext, &page_owner_ops); 144} 145 146static noinline depot_stack_handle_t save_stack(gfp_t flags) 147{ 148 unsigned long entries[PAGE_OWNER_STACK_DEPTH]; 149 depot_stack_handle_t handle; 150 unsigned int nr_entries; 151 152 if (current->in_page_owner) 153 return dummy_handle; 154 155 set_current_in_page_owner(); 156 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2); 157 handle = stack_depot_save(entries, nr_entries, flags); 158 if (!handle) 159 handle = failure_handle; 160 unset_current_in_page_owner(); 161 162 return handle; 163} 164 165static void add_stack_record_to_list(struct stack_record *stack_record, 166 gfp_t gfp_mask) 167{ 168 unsigned long flags; 169 struct stack *stack; 170 171 /* Filter gfp_mask the same way stackdepot does, for consistency */ 172 gfp_mask &= ~GFP_ZONEMASK; 173 gfp_mask &= (GFP_ATOMIC | GFP_KERNEL); 174 gfp_mask |= __GFP_NOWARN; 175 176 set_current_in_page_owner(); 177 stack = kmalloc(sizeof(*stack), gfp_mask); 178 if (!stack) { 179 unset_current_in_page_owner(); 180 return; 181 } 182 unset_current_in_page_owner(); 183 184 stack->stack_record = stack_record; 185 stack->next = NULL; 186 187 spin_lock_irqsave(&stack_list_lock, flags); 188 stack->next = stack_list; 189 /* 190 * This pairs with smp_load_acquire() from function 191 * stack_start(). This guarantees that stack_start() 192 * will see an updated stack_list before starting to 193 * traverse the list. 194 */ 195 smp_store_release(&stack_list, stack); 196 spin_unlock_irqrestore(&stack_list_lock, flags); 197} 198 199static void inc_stack_record_count(depot_stack_handle_t handle, gfp_t gfp_mask, 200 int nr_base_pages) 201{ 202 struct stack_record *stack_record = __stack_depot_get_stack_record(handle); 203 204 if (!stack_record) 205 return; 206 207 /* 208 * New stack_record's that do not use STACK_DEPOT_FLAG_GET start 209 * with REFCOUNT_SATURATED to catch spurious increments of their 210 * refcount. 211 * Since we do not use STACK_DEPOT_FLAG_GET API, let us 212 * set a refcount of 1 ourselves. 213 */ 214 if (refcount_read(&stack_record->count) == REFCOUNT_SATURATED) { 215 int old = REFCOUNT_SATURATED; 216 217 if (atomic_try_cmpxchg_relaxed(&stack_record->count.refs, &old, 1)) 218 /* Add the new stack_record to our list */ 219 add_stack_record_to_list(stack_record, gfp_mask); 220 } 221 refcount_add(nr_base_pages, &stack_record->count); 222} 223 224static void dec_stack_record_count(depot_stack_handle_t handle, 225 int nr_base_pages) 226{ 227 struct stack_record *stack_record = __stack_depot_get_stack_record(handle); 228 229 if (!stack_record) 230 return; 231 232 if (refcount_sub_and_test(nr_base_pages, &stack_record->count)) 233 pr_warn("%s: refcount went to 0 for %u handle\n", __func__, 234 handle); 235} 236 237static inline void __update_page_owner_handle(struct page_ext *page_ext, 238 depot_stack_handle_t handle, 239 unsigned short order, 240 gfp_t gfp_mask, 241 short last_migrate_reason, u64 ts_nsec, 242 pid_t pid, pid_t tgid, char *comm) 243{ 244 int i; 245 struct page_owner *page_owner; 246 247 for (i = 0; i < (1 << order); i++) { 248 page_owner = get_page_owner(page_ext); 249 page_owner->handle = handle; 250 page_owner->order = order; 251 page_owner->gfp_mask = gfp_mask; 252 page_owner->last_migrate_reason = last_migrate_reason; 253 page_owner->pid = pid; 254 page_owner->tgid = tgid; 255 page_owner->ts_nsec = ts_nsec; 256 strscpy(page_owner->comm, comm, 257 sizeof(page_owner->comm)); 258 __set_bit(PAGE_EXT_OWNER, &page_ext->flags); 259 __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); 260 page_ext = page_ext_next(page_ext); 261 } 262} 263 264static inline void __update_page_owner_free_handle(struct page_ext *page_ext, 265 depot_stack_handle_t handle, 266 unsigned short order, 267 pid_t pid, pid_t tgid, 268 u64 free_ts_nsec) 269{ 270 int i; 271 struct page_owner *page_owner; 272 273 for (i = 0; i < (1 << order); i++) { 274 page_owner = get_page_owner(page_ext); 275 /* Only __reset_page_owner() wants to clear the bit */ 276 if (handle) { 277 __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); 278 page_owner->free_handle = handle; 279 } 280 page_owner->free_ts_nsec = free_ts_nsec; 281 page_owner->free_pid = current->pid; 282 page_owner->free_tgid = current->tgid; 283 page_ext = page_ext_next(page_ext); 284 } 285} 286 287void __reset_page_owner(struct page *page, unsigned short order) 288{ 289 struct page_ext *page_ext; 290 depot_stack_handle_t handle; 291 depot_stack_handle_t alloc_handle; 292 struct page_owner *page_owner; 293 u64 free_ts_nsec = local_clock(); 294 295 page_ext = page_ext_get(page); 296 if (unlikely(!page_ext)) 297 return; 298 299 page_owner = get_page_owner(page_ext); 300 alloc_handle = page_owner->handle; 301 302 handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); 303 __update_page_owner_free_handle(page_ext, handle, order, current->pid, 304 current->tgid, free_ts_nsec); 305 page_ext_put(page_ext); 306 307 if (alloc_handle != early_handle) 308 /* 309 * early_handle is being set as a handle for all those 310 * early allocated pages. See init_pages_in_zone(). 311 * Since their refcount is not being incremented because 312 * the machinery is not ready yet, we cannot decrement 313 * their refcount either. 314 */ 315 dec_stack_record_count(alloc_handle, 1 << order); 316} 317 318noinline void __set_page_owner(struct page *page, unsigned short order, 319 gfp_t gfp_mask) 320{ 321 struct page_ext *page_ext; 322 u64 ts_nsec = local_clock(); 323 depot_stack_handle_t handle; 324 325 handle = save_stack(gfp_mask); 326 327 page_ext = page_ext_get(page); 328 if (unlikely(!page_ext)) 329 return; 330 __update_page_owner_handle(page_ext, handle, order, gfp_mask, -1, 331 current->pid, current->tgid, ts_nsec, 332 current->comm); 333 page_ext_put(page_ext); 334 inc_stack_record_count(handle, gfp_mask, 1 << order); 335} 336 337void __set_page_owner_migrate_reason(struct page *page, int reason) 338{ 339 struct page_ext *page_ext = page_ext_get(page); 340 struct page_owner *page_owner; 341 342 if (unlikely(!page_ext)) 343 return; 344 345 page_owner = get_page_owner(page_ext); 346 page_owner->last_migrate_reason = reason; 347 page_ext_put(page_ext); 348} 349 350void __split_page_owner(struct page *page, int old_order, int new_order) 351{ 352 int i; 353 struct page_ext *page_ext = page_ext_get(page); 354 struct page_owner *page_owner; 355 356 if (unlikely(!page_ext)) 357 return; 358 359 for (i = 0; i < (1 << old_order); i++) { 360 page_owner = get_page_owner(page_ext); 361 page_owner->order = new_order; 362 page_ext = page_ext_next(page_ext); 363 } 364 page_ext_put(page_ext); 365} 366 367void __folio_copy_owner(struct folio *newfolio, struct folio *old) 368{ 369 int i; 370 struct page_ext *old_ext; 371 struct page_ext *new_ext; 372 struct page_owner *old_page_owner; 373 struct page_owner *new_page_owner; 374 depot_stack_handle_t migrate_handle; 375 376 old_ext = page_ext_get(&old->page); 377 if (unlikely(!old_ext)) 378 return; 379 380 new_ext = page_ext_get(&newfolio->page); 381 if (unlikely(!new_ext)) { 382 page_ext_put(old_ext); 383 return; 384 } 385 386 old_page_owner = get_page_owner(old_ext); 387 new_page_owner = get_page_owner(new_ext); 388 migrate_handle = new_page_owner->handle; 389 __update_page_owner_handle(new_ext, old_page_owner->handle, 390 old_page_owner->order, old_page_owner->gfp_mask, 391 old_page_owner->last_migrate_reason, 392 old_page_owner->ts_nsec, old_page_owner->pid, 393 old_page_owner->tgid, old_page_owner->comm); 394 /* 395 * Do not proactively clear PAGE_EXT_OWNER{_ALLOCATED} bits as the folio 396 * will be freed after migration. Keep them until then as they may be 397 * useful. 398 */ 399 __update_page_owner_free_handle(new_ext, 0, old_page_owner->order, 400 old_page_owner->free_pid, 401 old_page_owner->free_tgid, 402 old_page_owner->free_ts_nsec); 403 /* 404 * We linked the original stack to the new folio, we need to do the same 405 * for the new one and the old folio otherwise there will be an imbalance 406 * when subtracting those pages from the stack. 407 */ 408 for (i = 0; i < (1 << new_page_owner->order); i++) { 409 old_page_owner->handle = migrate_handle; 410 old_ext = page_ext_next(old_ext); 411 old_page_owner = get_page_owner(old_ext); 412 } 413 414 page_ext_put(new_ext); 415 page_ext_put(old_ext); 416} 417 418void pagetypeinfo_showmixedcount_print(struct seq_file *m, 419 pg_data_t *pgdat, struct zone *zone) 420{ 421 struct page *page; 422 struct page_ext *page_ext; 423 struct page_owner *page_owner; 424 unsigned long pfn, block_end_pfn; 425 unsigned long end_pfn = zone_end_pfn(zone); 426 unsigned long count[MIGRATE_TYPES] = { 0, }; 427 int pageblock_mt, page_mt; 428 int i; 429 430 /* Scan block by block. First and last block may be incomplete */ 431 pfn = zone->zone_start_pfn; 432 433 /* 434 * Walk the zone in pageblock_nr_pages steps. If a page block spans 435 * a zone boundary, it will be double counted between zones. This does 436 * not matter as the mixed block count will still be correct 437 */ 438 for (; pfn < end_pfn; ) { 439 page = pfn_to_online_page(pfn); 440 if (!page) { 441 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); 442 continue; 443 } 444 445 block_end_pfn = pageblock_end_pfn(pfn); 446 block_end_pfn = min(block_end_pfn, end_pfn); 447 448 pageblock_mt = get_pageblock_migratetype(page); 449 450 for (; pfn < block_end_pfn; pfn++) { 451 /* The pageblock is online, no need to recheck. */ 452 page = pfn_to_page(pfn); 453 454 if (page_zone(page) != zone) 455 continue; 456 457 if (PageBuddy(page)) { 458 unsigned long freepage_order; 459 460 freepage_order = buddy_order_unsafe(page); 461 if (freepage_order <= MAX_PAGE_ORDER) 462 pfn += (1UL << freepage_order) - 1; 463 continue; 464 } 465 466 if (PageReserved(page)) 467 continue; 468 469 page_ext = page_ext_get(page); 470 if (unlikely(!page_ext)) 471 continue; 472 473 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags)) 474 goto ext_put_continue; 475 476 page_owner = get_page_owner(page_ext); 477 page_mt = gfp_migratetype(page_owner->gfp_mask); 478 if (pageblock_mt != page_mt) { 479 if (is_migrate_cma(pageblock_mt)) 480 count[MIGRATE_MOVABLE]++; 481 else 482 count[pageblock_mt]++; 483 484 pfn = block_end_pfn; 485 page_ext_put(page_ext); 486 break; 487 } 488 pfn += (1UL << page_owner->order) - 1; 489ext_put_continue: 490 page_ext_put(page_ext); 491 } 492 } 493 494 /* Print counts */ 495 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name); 496 for (i = 0; i < MIGRATE_TYPES; i++) 497 seq_printf(m, "%12lu ", count[i]); 498 seq_putc(m, '\n'); 499} 500 501/* 502 * Looking for memcg information and print it out 503 */ 504static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret, 505 struct page *page) 506{ 507#ifdef CONFIG_MEMCG 508 unsigned long memcg_data; 509 struct mem_cgroup *memcg; 510 bool online; 511 char name[80]; 512 513 rcu_read_lock(); 514 memcg_data = READ_ONCE(page->memcg_data); 515 if (!memcg_data) 516 goto out_unlock; 517 518 if (memcg_data & MEMCG_DATA_OBJCGS) 519 ret += scnprintf(kbuf + ret, count - ret, 520 "Slab cache page\n"); 521 522 memcg = page_memcg_check(page); 523 if (!memcg) 524 goto out_unlock; 525 526 online = (memcg->css.flags & CSS_ONLINE); 527 cgroup_name(memcg->css.cgroup, name, sizeof(name)); 528 ret += scnprintf(kbuf + ret, count - ret, 529 "Charged %sto %smemcg %s\n", 530 PageMemcgKmem(page) ? "(via objcg) " : "", 531 online ? "" : "offline ", 532 name); 533out_unlock: 534 rcu_read_unlock(); 535#endif /* CONFIG_MEMCG */ 536 537 return ret; 538} 539 540static ssize_t 541print_page_owner(char __user *buf, size_t count, unsigned long pfn, 542 struct page *page, struct page_owner *page_owner, 543 depot_stack_handle_t handle) 544{ 545 int ret, pageblock_mt, page_mt; 546 char *kbuf; 547 548 count = min_t(size_t, count, PAGE_SIZE); 549 kbuf = kmalloc(count, GFP_KERNEL); 550 if (!kbuf) 551 return -ENOMEM; 552 553 ret = scnprintf(kbuf, count, 554 "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns\n", 555 page_owner->order, page_owner->gfp_mask, 556 &page_owner->gfp_mask, page_owner->pid, 557 page_owner->tgid, page_owner->comm, 558 page_owner->ts_nsec); 559 560 /* Print information relevant to grouping pages by mobility */ 561 pageblock_mt = get_pageblock_migratetype(page); 562 page_mt = gfp_migratetype(page_owner->gfp_mask); 563 ret += scnprintf(kbuf + ret, count - ret, 564 "PFN 0x%lx type %s Block %lu type %s Flags %pGp\n", 565 pfn, 566 migratetype_names[page_mt], 567 pfn >> pageblock_order, 568 migratetype_names[pageblock_mt], 569 &page->flags); 570 571 ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0); 572 if (ret >= count) 573 goto err; 574 575 if (page_owner->last_migrate_reason != -1) { 576 ret += scnprintf(kbuf + ret, count - ret, 577 "Page has been migrated, last migrate reason: %s\n", 578 migrate_reason_names[page_owner->last_migrate_reason]); 579 } 580 581 ret = print_page_owner_memcg(kbuf, count, ret, page); 582 583 ret += snprintf(kbuf + ret, count - ret, "\n"); 584 if (ret >= count) 585 goto err; 586 587 if (copy_to_user(buf, kbuf, ret)) 588 ret = -EFAULT; 589 590 kfree(kbuf); 591 return ret; 592 593err: 594 kfree(kbuf); 595 return -ENOMEM; 596} 597 598void __dump_page_owner(const struct page *page) 599{ 600 struct page_ext *page_ext = page_ext_get((void *)page); 601 struct page_owner *page_owner; 602 depot_stack_handle_t handle; 603 gfp_t gfp_mask; 604 int mt; 605 606 if (unlikely(!page_ext)) { 607 pr_alert("There is not page extension available.\n"); 608 return; 609 } 610 611 page_owner = get_page_owner(page_ext); 612 gfp_mask = page_owner->gfp_mask; 613 mt = gfp_migratetype(gfp_mask); 614 615 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) { 616 pr_alert("page_owner info is not present (never set?)\n"); 617 page_ext_put(page_ext); 618 return; 619 } 620 621 if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags)) 622 pr_alert("page_owner tracks the page as allocated\n"); 623 else 624 pr_alert("page_owner tracks the page as freed\n"); 625 626 pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu, free_ts %llu\n", 627 page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask, 628 page_owner->pid, page_owner->tgid, page_owner->comm, 629 page_owner->ts_nsec, page_owner->free_ts_nsec); 630 631 handle = READ_ONCE(page_owner->handle); 632 if (!handle) 633 pr_alert("page_owner allocation stack trace missing\n"); 634 else 635 stack_depot_print(handle); 636 637 handle = READ_ONCE(page_owner->free_handle); 638 if (!handle) { 639 pr_alert("page_owner free stack trace missing\n"); 640 } else { 641 pr_alert("page last free pid %d tgid %d stack trace:\n", 642 page_owner->free_pid, page_owner->free_tgid); 643 stack_depot_print(handle); 644 } 645 646 if (page_owner->last_migrate_reason != -1) 647 pr_alert("page has been migrated, last migrate reason: %s\n", 648 migrate_reason_names[page_owner->last_migrate_reason]); 649 page_ext_put(page_ext); 650} 651 652static ssize_t 653read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) 654{ 655 unsigned long pfn; 656 struct page *page; 657 struct page_ext *page_ext; 658 struct page_owner *page_owner; 659 depot_stack_handle_t handle; 660 661 if (!static_branch_unlikely(&page_owner_inited)) 662 return -EINVAL; 663 664 page = NULL; 665 if (*ppos == 0) 666 pfn = min_low_pfn; 667 else 668 pfn = *ppos; 669 /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ 670 while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) 671 pfn++; 672 673 /* Find an allocated page */ 674 for (; pfn < max_pfn; pfn++) { 675 /* 676 * This temporary page_owner is required so 677 * that we can avoid the context switches while holding 678 * the rcu lock and copying the page owner information to 679 * user through copy_to_user() or GFP_KERNEL allocations. 680 */ 681 struct page_owner page_owner_tmp; 682 683 /* 684 * If the new page is in a new MAX_ORDER_NR_PAGES area, 685 * validate the area as existing, skip it if not 686 */ 687 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) { 688 pfn += MAX_ORDER_NR_PAGES - 1; 689 continue; 690 } 691 692 page = pfn_to_page(pfn); 693 if (PageBuddy(page)) { 694 unsigned long freepage_order = buddy_order_unsafe(page); 695 696 if (freepage_order <= MAX_PAGE_ORDER) 697 pfn += (1UL << freepage_order) - 1; 698 continue; 699 } 700 701 page_ext = page_ext_get(page); 702 if (unlikely(!page_ext)) 703 continue; 704 705 /* 706 * Some pages could be missed by concurrent allocation or free, 707 * because we don't hold the zone lock. 708 */ 709 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) 710 goto ext_put_continue; 711 712 /* 713 * Although we do have the info about past allocation of free 714 * pages, it's not relevant for current memory usage. 715 */ 716 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags)) 717 goto ext_put_continue; 718 719 page_owner = get_page_owner(page_ext); 720 721 /* 722 * Don't print "tail" pages of high-order allocations as that 723 * would inflate the stats. 724 */ 725 if (!IS_ALIGNED(pfn, 1 << page_owner->order)) 726 goto ext_put_continue; 727 728 /* 729 * Access to page_ext->handle isn't synchronous so we should 730 * be careful to access it. 731 */ 732 handle = READ_ONCE(page_owner->handle); 733 if (!handle) 734 goto ext_put_continue; 735 736 /* Record the next PFN to read in the file offset */ 737 *ppos = pfn + 1; 738 739 page_owner_tmp = *page_owner; 740 page_ext_put(page_ext); 741 return print_page_owner(buf, count, pfn, page, 742 &page_owner_tmp, handle); 743ext_put_continue: 744 page_ext_put(page_ext); 745 } 746 747 return 0; 748} 749 750static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig) 751{ 752 switch (orig) { 753 case SEEK_SET: 754 file->f_pos = offset; 755 break; 756 case SEEK_CUR: 757 file->f_pos += offset; 758 break; 759 default: 760 return -EINVAL; 761 } 762 return file->f_pos; 763} 764 765static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) 766{ 767 unsigned long pfn = zone->zone_start_pfn; 768 unsigned long end_pfn = zone_end_pfn(zone); 769 unsigned long count = 0; 770 771 /* 772 * Walk the zone in pageblock_nr_pages steps. If a page block spans 773 * a zone boundary, it will be double counted between zones. This does 774 * not matter as the mixed block count will still be correct 775 */ 776 for (; pfn < end_pfn; ) { 777 unsigned long block_end_pfn; 778 779 if (!pfn_valid(pfn)) { 780 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); 781 continue; 782 } 783 784 block_end_pfn = pageblock_end_pfn(pfn); 785 block_end_pfn = min(block_end_pfn, end_pfn); 786 787 for (; pfn < block_end_pfn; pfn++) { 788 struct page *page = pfn_to_page(pfn); 789 struct page_ext *page_ext; 790 791 if (page_zone(page) != zone) 792 continue; 793 794 /* 795 * To avoid having to grab zone->lock, be a little 796 * careful when reading buddy page order. The only 797 * danger is that we skip too much and potentially miss 798 * some early allocated pages, which is better than 799 * heavy lock contention. 800 */ 801 if (PageBuddy(page)) { 802 unsigned long order = buddy_order_unsafe(page); 803 804 if (order > 0 && order <= MAX_PAGE_ORDER) 805 pfn += (1UL << order) - 1; 806 continue; 807 } 808 809 if (PageReserved(page)) 810 continue; 811 812 page_ext = page_ext_get(page); 813 if (unlikely(!page_ext)) 814 continue; 815 816 /* Maybe overlapping zone */ 817 if (test_bit(PAGE_EXT_OWNER, &page_ext->flags)) 818 goto ext_put_continue; 819 820 /* Found early allocated page */ 821 __update_page_owner_handle(page_ext, early_handle, 0, 0, 822 -1, local_clock(), current->pid, 823 current->tgid, current->comm); 824 count++; 825ext_put_continue: 826 page_ext_put(page_ext); 827 } 828 cond_resched(); 829 } 830 831 pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n", 832 pgdat->node_id, zone->name, count); 833} 834 835static void init_zones_in_node(pg_data_t *pgdat) 836{ 837 struct zone *zone; 838 struct zone *node_zones = pgdat->node_zones; 839 840 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { 841 if (!populated_zone(zone)) 842 continue; 843 844 init_pages_in_zone(pgdat, zone); 845 } 846} 847 848static void init_early_allocated_pages(void) 849{ 850 pg_data_t *pgdat; 851 852 for_each_online_pgdat(pgdat) 853 init_zones_in_node(pgdat); 854} 855 856static const struct file_operations proc_page_owner_operations = { 857 .read = read_page_owner, 858 .llseek = lseek_page_owner, 859}; 860 861static void *stack_start(struct seq_file *m, loff_t *ppos) 862{ 863 struct stack *stack; 864 865 if (*ppos == -1UL) 866 return NULL; 867 868 if (!*ppos) { 869 /* 870 * This pairs with smp_store_release() from function 871 * add_stack_record_to_list(), so we get a consistent 872 * value of stack_list. 873 */ 874 stack = smp_load_acquire(&stack_list); 875 m->private = stack; 876 } else { 877 stack = m->private; 878 } 879 880 return stack; 881} 882 883static void *stack_next(struct seq_file *m, void *v, loff_t *ppos) 884{ 885 struct stack *stack = v; 886 887 stack = stack->next; 888 *ppos = stack ? *ppos + 1 : -1UL; 889 m->private = stack; 890 891 return stack; 892} 893 894static unsigned long page_owner_pages_threshold; 895 896static int stack_print(struct seq_file *m, void *v) 897{ 898 int i, nr_base_pages; 899 struct stack *stack = v; 900 unsigned long *entries; 901 unsigned long nr_entries; 902 struct stack_record *stack_record = stack->stack_record; 903 904 if (!stack->stack_record) 905 return 0; 906 907 nr_entries = stack_record->size; 908 entries = stack_record->entries; 909 nr_base_pages = refcount_read(&stack_record->count) - 1; 910 911 if (nr_base_pages < 1 || nr_base_pages < page_owner_pages_threshold) 912 return 0; 913 914 for (i = 0; i < nr_entries; i++) 915 seq_printf(m, " %pS\n", (void *)entries[i]); 916 seq_printf(m, "nr_base_pages: %d\n\n", nr_base_pages); 917 918 return 0; 919} 920 921static void stack_stop(struct seq_file *m, void *v) 922{ 923} 924 925static const struct seq_operations page_owner_stack_op = { 926 .start = stack_start, 927 .next = stack_next, 928 .stop = stack_stop, 929 .show = stack_print 930}; 931 932static int page_owner_stack_open(struct inode *inode, struct file *file) 933{ 934 return seq_open_private(file, &page_owner_stack_op, 0); 935} 936 937static const struct file_operations page_owner_stack_operations = { 938 .open = page_owner_stack_open, 939 .read = seq_read, 940 .llseek = seq_lseek, 941 .release = seq_release, 942}; 943 944static int page_owner_threshold_get(void *data, u64 *val) 945{ 946 *val = READ_ONCE(page_owner_pages_threshold); 947 return 0; 948} 949 950static int page_owner_threshold_set(void *data, u64 val) 951{ 952 WRITE_ONCE(page_owner_pages_threshold, val); 953 return 0; 954} 955 956DEFINE_SIMPLE_ATTRIBUTE(proc_page_owner_threshold, &page_owner_threshold_get, 957 &page_owner_threshold_set, "%llu"); 958 959 960static int __init pageowner_init(void) 961{ 962 struct dentry *dir; 963 964 if (!static_branch_unlikely(&page_owner_inited)) { 965 pr_info("page_owner is disabled\n"); 966 return 0; 967 } 968 969 debugfs_create_file("page_owner", 0400, NULL, NULL, 970 &proc_page_owner_operations); 971 dir = debugfs_create_dir("page_owner_stacks", NULL); 972 debugfs_create_file("show_stacks", 0400, dir, NULL, 973 &page_owner_stack_operations); 974 debugfs_create_file("count_threshold", 0600, dir, NULL, 975 &proc_page_owner_threshold); 976 977 return 0; 978} 979late_initcall(pageowner_init) 980