mm/page_owner.c

   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 };
  36
  37 static bool page_owner_enabled __initdata;
  38 DEFINE_STATIC_KEY_FALSE(page_owner_inited);
  39
  40 static depot_stack_handle_t dummy_handle;
  41 static depot_stack_handle_t failure_handle;
  42 static depot_stack_handle_t early_handle;
  43
  44 static void init_early_allocated_pages(void);
  45
  46 static int __init early_page_owner_param(char *buf)
  47 {
  48         int ret = kstrtobool(buf, &page_owner_enabled);
  49
  50         if (page_owner_enabled)
  51                 stack_depot_want_early_init();
  52
  53         return ret;
  54 }
  55 early_param("page_owner", early_page_owner_param);
  56
  57 static __init bool need_page_owner(void)
  58 {
  59         return page_owner_enabled;
  60 }
  61
  62 static __always_inline depot_stack_handle_t create_dummy_stack(void)
  63 {
  64         unsigned long entries[4];
  65         unsigned int nr_entries;
  66
  67         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
  68         return stack_depot_save(entries, nr_entries, GFP_KERNEL);
  69 }
  70
  71 static noinline void register_dummy_stack(void)
  72 {
  73         dummy_handle = create_dummy_stack();
  74 }
  75
  76 static noinline void register_failure_stack(void)
  77 {
  78         failure_handle = create_dummy_stack();
  79 }
  80
  81 static noinline void register_early_stack(void)
  82 {
  83         early_handle = create_dummy_stack();
  84 }
  85
  86 static __init void init_page_owner(void)
  87 {
  88         if (!page_owner_enabled)
  89                 return;
  90
  91         register_dummy_stack();
  92         register_failure_stack();
  93         register_early_stack();
  94         static_branch_enable(&page_owner_inited);
  95         init_early_allocated_pages();
  96 }
  97
  98 struct page_ext_operations page_owner_ops = {
  99         .size = sizeof(struct page_owner),
 100         .need = need_page_owner,
 101         .init = init_page_owner,
 102 };
 103
 104 static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
 105 {
 106         return (void *)page_ext + page_owner_ops.offset;
 107 }
 108
 109 static noinline depot_stack_handle_t save_stack(gfp_t flags)
 110 {
 111         unsigned long entries[PAGE_OWNER_STACK_DEPTH];
 112         depot_stack_handle_t handle;
 113         unsigned int nr_entries;
 114
 115         /*
 116          * Avoid recursion.
 117          *
 118          * Sometimes page metadata allocation tracking requires more
 119          * memory to be allocated:
 120          * - when new stack trace is saved to stack depot
 121          * - when backtrace itself is calculated (ia64)
 122          */
 123         if (current->in_page_owner)
 124                 return dummy_handle;
 125         current->in_page_owner = 1;
 126
 127         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2);
 128         handle = stack_depot_save(entries, nr_entries, flags);
 129         if (!handle)
 130                 handle = failure_handle;
 131
 132         current->in_page_owner = 0;
 133         return handle;
 134 }
 135
 136 void __reset_page_owner(struct page *page, unsigned short order)
 137 {
 138         int i;
 139         struct page_ext *page_ext;
 140         depot_stack_handle_t handle;
 141         struct page_owner *page_owner;
 142         u64 free_ts_nsec = local_clock();
 143
 144         page_ext = page_ext_get(page);
 145         if (unlikely(!page_ext))
 146                 return;
 147
 148         handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
 149         for (i = 0; i < (1 << order); i++) {
 150                 __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
 151                 page_owner = get_page_owner(page_ext);
 152                 page_owner->free_handle = handle;
 153                 page_owner->free_ts_nsec = free_ts_nsec;
 154                 page_ext = page_ext_next(page_ext);
 155         }
 156         page_ext_put(page_ext);
 157 }
 158
 159 static inline void __set_page_owner_handle(struct page_ext *page_ext,
 160                                         depot_stack_handle_t handle,
 161                                         unsigned short order, gfp_t gfp_mask)
 162 {
 163         struct page_owner *page_owner;
 164         int i;
 165
 166         for (i = 0; i < (1 << order); i++) {
 167                 page_owner = get_page_owner(page_ext);
 168                 page_owner->handle = handle;
 169                 page_owner->order = order;
 170                 page_owner->gfp_mask = gfp_mask;
 171                 page_owner->last_migrate_reason = -1;
 172                 page_owner->pid = current->pid;
 173                 page_owner->tgid = current->tgid;
 174                 page_owner->ts_nsec = local_clock();
 175                 strscpy(page_owner->comm, current->comm,
 176                         sizeof(page_owner->comm));
 177                 __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
 178                 __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
 179
 180                 page_ext = page_ext_next(page_ext);
 181         }
 182 }
 183
 184 noinline void __set_page_owner(struct page *page, unsigned short order,
 185                                         gfp_t gfp_mask)
 186 {
 187         struct page_ext *page_ext;
 188         depot_stack_handle_t handle;
 189
 190         handle = save_stack(gfp_mask);
 191
 192         page_ext = page_ext_get(page);
 193         if (unlikely(!page_ext))
 194                 return;
 195         __set_page_owner_handle(page_ext, handle, order, gfp_mask);
 196         page_ext_put(page_ext);
 197 }
 198
 199 void __set_page_owner_migrate_reason(struct page *page, int reason)
 200 {
 201         struct page_ext *page_ext = page_ext_get(page);
 202         struct page_owner *page_owner;
 203
 204         if (unlikely(!page_ext))
 205                 return;
 206
 207         page_owner = get_page_owner(page_ext);
 208         page_owner->last_migrate_reason = reason;
 209         page_ext_put(page_ext);
 210 }
 211
 212 void __split_page_owner(struct page *page, unsigned int nr)
 213 {
 214         int i;
 215         struct page_ext *page_ext = page_ext_get(page);
 216         struct page_owner *page_owner;
 217
 218         if (unlikely(!page_ext))
 219                 return;
 220
 221         for (i = 0; i < nr; i++) {
 222                 page_owner = get_page_owner(page_ext);
 223                 page_owner->order = 0;
 224                 page_ext = page_ext_next(page_ext);
 225         }
 226         page_ext_put(page_ext);
 227 }
 228
 229 void __folio_copy_owner(struct folio *newfolio, struct folio *old)
 230 {
 231         struct page_ext *old_ext;
 232         struct page_ext *new_ext;
 233         struct page_owner *old_page_owner, *new_page_owner;
 234
 235         old_ext = page_ext_get(&old->page);
 236         if (unlikely(!old_ext))
 237                 return;
 238
 239         new_ext = page_ext_get(&newfolio->page);
 240         if (unlikely(!new_ext)) {
 241                 page_ext_put(old_ext);
 242                 return;
 243         }
 244
 245         old_page_owner = get_page_owner(old_ext);
 246         new_page_owner = get_page_owner(new_ext);
 247         new_page_owner->order = old_page_owner->order;
 248         new_page_owner->gfp_mask = old_page_owner->gfp_mask;
 249         new_page_owner->last_migrate_reason =
 250                 old_page_owner->last_migrate_reason;
 251         new_page_owner->handle = old_page_owner->handle;
 252         new_page_owner->pid = old_page_owner->pid;
 253         new_page_owner->tgid = old_page_owner->tgid;
 254         new_page_owner->ts_nsec = old_page_owner->ts_nsec;
 255         new_page_owner->free_ts_nsec = old_page_owner->ts_nsec;
 256         strcpy(new_page_owner->comm, old_page_owner->comm);
 257
 258         /*
 259          * We don't clear the bit on the old folio as it's going to be freed
 260          * after migration. Until then, the info can be useful in case of
 261          * a bug, and the overall stats will be off a bit only temporarily.
 262          * Also, migrate_misplaced_transhuge_page() can still fail the
 263          * migration and then we want the old folio to retain the info. But
 264          * in that case we also don't need to explicitly clear the info from
 265          * the new page, which will be freed.
 266          */
 267         __set_bit(PAGE_EXT_OWNER, &new_ext->flags);
 268         __set_bit(PAGE_EXT_OWNER_ALLOCATED, &new_ext->flags);
 269         page_ext_put(new_ext);
 270         page_ext_put(old_ext);
 271 }
 272
 273 void pagetypeinfo_showmixedcount_print(struct seq_file *m,
 274                                        pg_data_t *pgdat, struct zone *zone)
 275 {
 276         struct page *page;
 277         struct page_ext *page_ext;
 278         struct page_owner *page_owner;
 279         unsigned long pfn, block_end_pfn;
 280         unsigned long end_pfn = zone_end_pfn(zone);
 281         unsigned long count[MIGRATE_TYPES] = { 0, };
 282         int pageblock_mt, page_mt;
 283         int i;
 284
 285         /* Scan block by block. First and last block may be incomplete */
 286         pfn = zone->zone_start_pfn;
 287
 288         /*
 289          * Walk the zone in pageblock_nr_pages steps. If a page block spans
 290          * a zone boundary, it will be double counted between zones. This does
 291          * not matter as the mixed block count will still be correct
 292          */
 293         for (; pfn < end_pfn; ) {
 294                 page = pfn_to_online_page(pfn);
 295                 if (!page) {
 296                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
 297                         continue;
 298                 }
 299
 300                 block_end_pfn = pageblock_end_pfn(pfn);
 301                 block_end_pfn = min(block_end_pfn, end_pfn);
 302
 303                 pageblock_mt = get_pageblock_migratetype(page);
 304
 305                 for (; pfn < block_end_pfn; pfn++) {
 306                         /* The pageblock is online, no need to recheck. */
 307                         page = pfn_to_page(pfn);
 308
 309                         if (page_zone(page) != zone)
 310                                 continue;
 311
 312                         if (PageBuddy(page)) {
 313                                 unsigned long freepage_order;
 314
 315                                 freepage_order = buddy_order_unsafe(page);
 316                                 if (freepage_order < MAX_ORDER)
 317                                         pfn += (1UL << freepage_order) - 1;
 318                                 continue;
 319                         }
 320
 321                         if (PageReserved(page))
 322                                 continue;
 323
 324                         page_ext = page_ext_get(page);
 325                         if (unlikely(!page_ext))
 326                                 continue;
 327
 328                         if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
 329                                 goto ext_put_continue;
 330
 331                         page_owner = get_page_owner(page_ext);
 332                         page_mt = gfp_migratetype(page_owner->gfp_mask);
 333                         if (pageblock_mt != page_mt) {
 334                                 if (is_migrate_cma(pageblock_mt))
 335                                         count[MIGRATE_MOVABLE]++;
 336                                 else
 337                                         count[pageblock_mt]++;
 338
 339                                 pfn = block_end_pfn;
 340                                 page_ext_put(page_ext);
 341                                 break;
 342                         }
 343                         pfn += (1UL << page_owner->order) - 1;
 344 ext_put_continue:
 345                         page_ext_put(page_ext);
 346                 }
 347         }
 348
 349         /* Print counts */
 350         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 351         for (i = 0; i < MIGRATE_TYPES; i++)
 352                 seq_printf(m, "%12lu ", count[i]);
 353         seq_putc(m, '\n');
 354 }
 355
 356 /*
 357  * Looking for memcg information and print it out
 358  */
 359 static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret,
 360                                          struct page *page)
 361 {
 362 #ifdef CONFIG_MEMCG
 363         unsigned long memcg_data;
 364         struct mem_cgroup *memcg;
 365         bool online;
 366         char name[80];
 367
 368         rcu_read_lock();
 369         memcg_data = READ_ONCE(page->memcg_data);
 370         if (!memcg_data)
 371                 goto out_unlock;
 372
 373         if (memcg_data & MEMCG_DATA_OBJCGS)
 374                 ret += scnprintf(kbuf + ret, count - ret,
 375                                 "Slab cache page\n");
 376
 377         memcg = page_memcg_check(page);
 378         if (!memcg)
 379                 goto out_unlock;
 380
 381         online = (memcg->css.flags & CSS_ONLINE);
 382         cgroup_name(memcg->css.cgroup, name, sizeof(name));
 383         ret += scnprintf(kbuf + ret, count - ret,
 384                         "Charged %sto %smemcg %s\n",
 385                         PageMemcgKmem(page) ? "(via objcg) " : "",
 386                         online ? "" : "offline ",
 387                         name);
 388 out_unlock:
 389         rcu_read_unlock();
 390 #endif /* CONFIG_MEMCG */
 391
 392         return ret;
 393 }
 394
 395 static ssize_t
 396 print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 397                 struct page *page, struct page_owner *page_owner,
 398                 depot_stack_handle_t handle)
 399 {
 400         int ret, pageblock_mt, page_mt;
 401         char *kbuf;
 402
 403         count = min_t(size_t, count, PAGE_SIZE);
 404         kbuf = kmalloc(count, GFP_KERNEL);
 405         if (!kbuf)
 406                 return -ENOMEM;
 407
 408         ret = scnprintf(kbuf, count,
 409                         "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns, free_ts %llu ns\n",
 410                         page_owner->order, page_owner->gfp_mask,
 411                         &page_owner->gfp_mask, page_owner->pid,
 412                         page_owner->tgid, page_owner->comm,
 413                         page_owner->ts_nsec, page_owner->free_ts_nsec);
 414
 415         /* Print information relevant to grouping pages by mobility */
 416         pageblock_mt = get_pageblock_migratetype(page);
 417         page_mt  = gfp_migratetype(page_owner->gfp_mask);
 418         ret += scnprintf(kbuf + ret, count - ret,
 419                         "PFN %lu type %s Block %lu type %s Flags %pGp\n",
 420                         pfn,
 421                         migratetype_names[page_mt],
 422                         pfn >> pageblock_order,
 423                         migratetype_names[pageblock_mt],
 424                         &page->flags);
 425
 426         ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0);
 427         if (ret >= count)
 428                 goto err;
 429
 430         if (page_owner->last_migrate_reason != -1) {
 431                 ret += scnprintf(kbuf + ret, count - ret,
 432                         "Page has been migrated, last migrate reason: %s\n",
 433                         migrate_reason_names[page_owner->last_migrate_reason]);
 434         }
 435
 436         ret = print_page_owner_memcg(kbuf, count, ret, page);
 437
 438         ret += snprintf(kbuf + ret, count - ret, "\n");
 439         if (ret >= count)
 440                 goto err;
 441
 442         if (copy_to_user(buf, kbuf, ret))
 443                 ret = -EFAULT;
 444
 445         kfree(kbuf);
 446         return ret;
 447
 448 err:
 449         kfree(kbuf);
 450         return -ENOMEM;
 451 }
 452
 453 void __dump_page_owner(const struct page *page)
 454 {
 455         struct page_ext *page_ext = page_ext_get((void *)page);
 456         struct page_owner *page_owner;
 457         depot_stack_handle_t handle;
 458         gfp_t gfp_mask;
 459         int mt;
 460
 461         if (unlikely(!page_ext)) {
 462                 pr_alert("There is not page extension available.\n");
 463                 return;
 464         }
 465
 466         page_owner = get_page_owner(page_ext);
 467         gfp_mask = page_owner->gfp_mask;
 468         mt = gfp_migratetype(gfp_mask);
 469
 470         if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
 471                 pr_alert("page_owner info is not present (never set?)\n");
 472                 page_ext_put(page_ext);
 473                 return;
 474         }
 475
 476         if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
 477                 pr_alert("page_owner tracks the page as allocated\n");
 478         else
 479                 pr_alert("page_owner tracks the page as freed\n");
 480
 481         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",
 482                  page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask,
 483                  page_owner->pid, page_owner->tgid, page_owner->comm,
 484                  page_owner->ts_nsec, page_owner->free_ts_nsec);
 485
 486         handle = READ_ONCE(page_owner->handle);
 487         if (!handle)
 488                 pr_alert("page_owner allocation stack trace missing\n");
 489         else
 490                 stack_depot_print(handle);
 491
 492         handle = READ_ONCE(page_owner->free_handle);
 493         if (!handle) {
 494                 pr_alert("page_owner free stack trace missing\n");
 495         } else {
 496                 pr_alert("page last free stack trace:\n");
 497                 stack_depot_print(handle);
 498         }
 499
 500         if (page_owner->last_migrate_reason != -1)
 501                 pr_alert("page has been migrated, last migrate reason: %s\n",
 502                         migrate_reason_names[page_owner->last_migrate_reason]);
 503         page_ext_put(page_ext);
 504 }
 505
 506 static ssize_t
 507 read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 508 {
 509         unsigned long pfn;
 510         struct page *page;
 511         struct page_ext *page_ext;
 512         struct page_owner *page_owner;
 513         depot_stack_handle_t handle;
 514
 515         if (!static_branch_unlikely(&page_owner_inited))
 516                 return -EINVAL;
 517
 518         page = NULL;
 519         if (*ppos == 0)
 520                 pfn = min_low_pfn;
 521         else
 522                 pfn = *ppos;
 523         /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
 524         while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
 525                 pfn++;
 526
 527         /* Find an allocated page */
 528         for (; pfn < max_pfn; pfn++) {
 529                 /*
 530                  * This temporary page_owner is required so
 531                  * that we can avoid the context switches while holding
 532                  * the rcu lock and copying the page owner information to
 533                  * user through copy_to_user() or GFP_KERNEL allocations.
 534                  */
 535                 struct page_owner page_owner_tmp;
 536
 537                 /*
 538                  * If the new page is in a new MAX_ORDER_NR_PAGES area,
 539                  * validate the area as existing, skip it if not
 540                  */
 541                 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
 542                         pfn += MAX_ORDER_NR_PAGES - 1;
 543                         continue;
 544                 }
 545
 546                 page = pfn_to_page(pfn);
 547                 if (PageBuddy(page)) {
 548                         unsigned long freepage_order = buddy_order_unsafe(page);
 549
 550                         if (freepage_order < MAX_ORDER)
 551                                 pfn += (1UL << freepage_order) - 1;
 552                         continue;
 553                 }
 554
 555                 page_ext = page_ext_get(page);
 556                 if (unlikely(!page_ext))
 557                         continue;
 558
 559                 /*
 560                  * Some pages could be missed by concurrent allocation or free,
 561                  * because we don't hold the zone lock.
 562                  */
 563                 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
 564                         goto ext_put_continue;
 565
 566                 /*
 567                  * Although we do have the info about past allocation of free
 568                  * pages, it's not relevant for current memory usage.
 569                  */
 570                 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
 571                         goto ext_put_continue;
 572
 573                 page_owner = get_page_owner(page_ext);
 574
 575                 /*
 576                  * Don't print "tail" pages of high-order allocations as that
 577                  * would inflate the stats.
 578                  */
 579                 if (!IS_ALIGNED(pfn, 1 << page_owner->order))
 580                         goto ext_put_continue;
 581
 582                 /*
 583                  * Access to page_ext->handle isn't synchronous so we should
 584                  * be careful to access it.
 585                  */
 586                 handle = READ_ONCE(page_owner->handle);
 587                 if (!handle)
 588                         goto ext_put_continue;
 589
 590                 /* Record the next PFN to read in the file offset */
 591                 *ppos = pfn + 1;
 592
 593                 page_owner_tmp = *page_owner;
 594                 page_ext_put(page_ext);
 595                 return print_page_owner(buf, count, pfn, page,
 596                                 &page_owner_tmp, handle);
 597 ext_put_continue:
 598                 page_ext_put(page_ext);
 599         }
 600
 601         return 0;
 602 }
 603
 604 static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig)
 605 {
 606         switch (orig) {
 607         case SEEK_SET:
 608                 file->f_pos = offset;
 609                 break;
 610         case SEEK_CUR:
 611                 file->f_pos += offset;
 612                 break;
 613         default:
 614                 return -EINVAL;
 615         }
 616         return file->f_pos;
 617 }
 618
 619 static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
 620 {
 621         unsigned long pfn = zone->zone_start_pfn;
 622         unsigned long end_pfn = zone_end_pfn(zone);
 623         unsigned long count = 0;
 624
 625         /*
 626          * Walk the zone in pageblock_nr_pages steps. If a page block spans
 627          * a zone boundary, it will be double counted between zones. This does
 628          * not matter as the mixed block count will still be correct
 629          */
 630         for (; pfn < end_pfn; ) {
 631                 unsigned long block_end_pfn;
 632
 633                 if (!pfn_valid(pfn)) {
 634                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
 635                         continue;
 636                 }
 637
 638                 block_end_pfn = pageblock_end_pfn(pfn);
 639                 block_end_pfn = min(block_end_pfn, end_pfn);
 640
 641                 for (; pfn < block_end_pfn; pfn++) {
 642                         struct page *page = pfn_to_page(pfn);
 643                         struct page_ext *page_ext;
 644
 645                         if (page_zone(page) != zone)
 646                                 continue;
 647
 648                         /*
 649                          * To avoid having to grab zone->lock, be a little
 650                          * careful when reading buddy page order. The only
 651                          * danger is that we skip too much and potentially miss
 652                          * some early allocated pages, which is better than
 653                          * heavy lock contention.
 654                          */
 655                         if (PageBuddy(page)) {
 656                                 unsigned long order = buddy_order_unsafe(page);
 657
 658                                 if (order > 0 && order < MAX_ORDER)
 659                                         pfn += (1UL << order) - 1;
 660                                 continue;
 661                         }
 662
 663                         if (PageReserved(page))
 664                                 continue;
 665
 666                         page_ext = page_ext_get(page);
 667                         if (unlikely(!page_ext))
 668                                 continue;
 669
 670                         /* Maybe overlapping zone */
 671                         if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
 672                                 goto ext_put_continue;
 673
 674                         /* Found early allocated page */
 675                         __set_page_owner_handle(page_ext, early_handle,
 676                                                 0, 0);
 677                         count++;
 678 ext_put_continue:
 679                         page_ext_put(page_ext);
 680                 }
 681                 cond_resched();
 682         }
 683
 684         pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
 685                 pgdat->node_id, zone->name, count);
 686 }
 687
 688 static void init_zones_in_node(pg_data_t *pgdat)
 689 {
 690         struct zone *zone;
 691         struct zone *node_zones = pgdat->node_zones;
 692
 693         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 694                 if (!populated_zone(zone))
 695                         continue;
 696
 697                 init_pages_in_zone(pgdat, zone);
 698         }
 699 }
 700
 701 static void init_early_allocated_pages(void)
 702 {
 703         pg_data_t *pgdat;
 704
 705         for_each_online_pgdat(pgdat)
 706                 init_zones_in_node(pgdat);
 707 }
 708
 709 static const struct file_operations proc_page_owner_operations = {
 710         .read           = read_page_owner,
 711         .llseek         = lseek_page_owner,
 712 };
 713
 714 static int __init pageowner_init(void)
 715 {
 716         if (!static_branch_unlikely(&page_owner_inited)) {
 717                 pr_info("page_owner is disabled\n");
 718                 return 0;
 719         }
 720
 721         debugfs_create_file("page_owner", 0400, NULL, NULL,
 722                             &proc_page_owner_operations);
 723
 724         return 0;
 725 }
 726 late_initcall(pageowner_init)