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