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_request_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         .need_shared_flags = true,
 103 };
 104
 105 static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
 106 {
 107         return page_ext_data(page_ext, &page_owner_ops);
 108 }
 109
 110 static noinline depot_stack_handle_t save_stack(gfp_t flags)
 111 {
 112         unsigned long entries[PAGE_OWNER_STACK_DEPTH];
 113         depot_stack_handle_t handle;
 114         unsigned int nr_entries;
 115
 116         /*
 117          * Avoid recursion.
 118          *
 119          * Sometimes page metadata allocation tracking requires more
 120          * memory to be allocated:
 121          * - when new stack trace is saved to stack depot
 122          * - when backtrace itself is calculated (ia64)
 123          */
 124         if (current->in_page_owner)
 125                 return dummy_handle;
 126         current->in_page_owner = 1;
 127
 128         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2);
 129         handle = stack_depot_save(entries, nr_entries, flags);
 130         if (!handle)
 131                 handle = failure_handle;
 132
 133         current->in_page_owner = 0;
 134         return handle;
 135 }
 136
 137 void __reset_page_owner(struct page *page, unsigned short order)
 138 {
 139         int i;
 140         struct page_ext *page_ext;
 141         depot_stack_handle_t handle;
 142         struct page_owner *page_owner;
 143         u64 free_ts_nsec = local_clock();
 144
 145         page_ext = page_ext_get(page);
 146         if (unlikely(!page_ext))
 147                 return;
 148
 149         handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
 150         for (i = 0; i < (1 << order); i++) {
 151                 __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
 152                 page_owner = get_page_owner(page_ext);
 153                 page_owner->free_handle = handle;
 154                 page_owner->free_ts_nsec = free_ts_nsec;
 155                 page_ext = page_ext_next(page_ext);
 156         }
 157         page_ext_put(page_ext);
 158 }
 159
 160 static inline void __set_page_owner_handle(struct page_ext *page_ext,
 161                                         depot_stack_handle_t handle,
 162                                         unsigned short order, gfp_t gfp_mask)
 163 {
 164         struct page_owner *page_owner;
 165         int i;
 166         u64 ts_nsec = local_clock();
 167
 168         for (i = 0; i < (1 << order); i++) {
 169                 page_owner = get_page_owner(page_ext);
 170                 page_owner->handle = handle;
 171                 page_owner->order = order;
 172                 page_owner->gfp_mask = gfp_mask;
 173                 page_owner->last_migrate_reason = -1;
 174                 page_owner->pid = current->pid;
 175                 page_owner->tgid = current->tgid;
 176                 page_owner->ts_nsec = ts_nsec;
 177                 strscpy(page_owner->comm, current->comm,
 178                         sizeof(page_owner->comm));
 179                 __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
 180                 __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
 181
 182                 page_ext = page_ext_next(page_ext);
 183         }
 184 }
 185
 186 noinline void __set_page_owner(struct page *page, unsigned short order,
 187                                         gfp_t gfp_mask)
 188 {
 189         struct page_ext *page_ext;
 190         depot_stack_handle_t handle;
 191
 192         handle = save_stack(gfp_mask);
 193
 194         page_ext = page_ext_get(page);
 195         if (unlikely(!page_ext))
 196                 return;
 197         __set_page_owner_handle(page_ext, handle, order, gfp_mask);
 198         page_ext_put(page_ext);
 199 }
 200
 201 void __set_page_owner_migrate_reason(struct page *page, int reason)
 202 {
 203         struct page_ext *page_ext = page_ext_get(page);
 204         struct page_owner *page_owner;
 205
 206         if (unlikely(!page_ext))
 207                 return;
 208
 209         page_owner = get_page_owner(page_ext);
 210         page_owner->last_migrate_reason = reason;
 211         page_ext_put(page_ext);
 212 }
 213
 214 void __split_page_owner(struct page *page, unsigned int nr)
 215 {
 216         int i;
 217         struct page_ext *page_ext = page_ext_get(page);
 218         struct page_owner *page_owner;
 219
 220         if (unlikely(!page_ext))
 221                 return;
 222
 223         for (i = 0; i < nr; i++) {
 224                 page_owner = get_page_owner(page_ext);
 225                 page_owner->order = 0;
 226                 page_ext = page_ext_next(page_ext);
 227         }
 228         page_ext_put(page_ext);
 229 }
 230
 231 void __folio_copy_owner(struct folio *newfolio, struct folio *old)
 232 {
 233         struct page_ext *old_ext;
 234         struct page_ext *new_ext;
 235         struct page_owner *old_page_owner, *new_page_owner;
 236
 237         old_ext = page_ext_get(&old->page);
 238         if (unlikely(!old_ext))
 239                 return;
 240
 241         new_ext = page_ext_get(&newfolio->page);
 242         if (unlikely(!new_ext)) {
 243                 page_ext_put(old_ext);
 244                 return;
 245         }
 246
 247         old_page_owner = get_page_owner(old_ext);
 248         new_page_owner = get_page_owner(new_ext);
 249         new_page_owner->order = old_page_owner->order;
 250         new_page_owner->gfp_mask = old_page_owner->gfp_mask;
 251         new_page_owner->last_migrate_reason =
 252                 old_page_owner->last_migrate_reason;
 253         new_page_owner->handle = old_page_owner->handle;
 254         new_page_owner->pid = old_page_owner->pid;
 255         new_page_owner->tgid = old_page_owner->tgid;
 256         new_page_owner->ts_nsec = old_page_owner->ts_nsec;
 257         new_page_owner->free_ts_nsec = old_page_owner->ts_nsec;
 258         strcpy(new_page_owner->comm, old_page_owner->comm);
 259
 260         /*
 261          * We don't clear the bit on the old folio as it's going to be freed
 262          * after migration. Until then, the info can be useful in case of
 263          * a bug, and the overall stats will be off a bit only temporarily.
 264          * Also, migrate_misplaced_transhuge_page() can still fail the
 265          * migration and then we want the old folio to retain the info. But
 266          * in that case we also don't need to explicitly clear the info from
 267          * the new page, which will be freed.
 268          */
 269         __set_bit(PAGE_EXT_OWNER, &new_ext->flags);
 270         __set_bit(PAGE_EXT_OWNER_ALLOCATED, &new_ext->flags);
 271         page_ext_put(new_ext);
 272         page_ext_put(old_ext);
 273 }
 274
 275 void pagetypeinfo_showmixedcount_print(struct seq_file *m,
 276                                        pg_data_t *pgdat, struct zone *zone)
 277 {
 278         struct page *page;
 279         struct page_ext *page_ext;
 280         struct page_owner *page_owner;
 281         unsigned long pfn, block_end_pfn;
 282         unsigned long end_pfn = zone_end_pfn(zone);
 283         unsigned long count[MIGRATE_TYPES] = { 0, };
 284         int pageblock_mt, page_mt;
 285         int i;
 286
 287         /* Scan block by block. First and last block may be incomplete */
 288         pfn = zone->zone_start_pfn;
 289
 290         /*
 291          * Walk the zone in pageblock_nr_pages steps. If a page block spans
 292          * a zone boundary, it will be double counted between zones. This does
 293          * not matter as the mixed block count will still be correct
 294          */
 295         for (; pfn < end_pfn; ) {
 296                 page = pfn_to_online_page(pfn);
 297                 if (!page) {
 298                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
 299                         continue;
 300                 }
 301
 302                 block_end_pfn = pageblock_end_pfn(pfn);
 303                 block_end_pfn = min(block_end_pfn, end_pfn);
 304
 305                 pageblock_mt = get_pageblock_migratetype(page);
 306
 307                 for (; pfn < block_end_pfn; pfn++) {
 308                         /* The pageblock is online, no need to recheck. */
 309                         page = pfn_to_page(pfn);
 310
 311                         if (page_zone(page) != zone)
 312                                 continue;
 313
 314                         if (PageBuddy(page)) {
 315                                 unsigned long freepage_order;
 316
 317                                 freepage_order = buddy_order_unsafe(page);
 318                                 if (freepage_order <= MAX_ORDER)
 319                                         pfn += (1UL << freepage_order) - 1;
 320                                 continue;
 321                         }
 322
 323                         if (PageReserved(page))
 324                                 continue;
 325
 326                         page_ext = page_ext_get(page);
 327                         if (unlikely(!page_ext))
 328                                 continue;
 329
 330                         if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
 331                                 goto ext_put_continue;
 332
 333                         page_owner = get_page_owner(page_ext);
 334                         page_mt = gfp_migratetype(page_owner->gfp_mask);
 335                         if (pageblock_mt != page_mt) {
 336                                 if (is_migrate_cma(pageblock_mt))
 337                                         count[MIGRATE_MOVABLE]++;
 338                                 else
 339                                         count[pageblock_mt]++;
 340
 341                                 pfn = block_end_pfn;
 342                                 page_ext_put(page_ext);
 343                                 break;
 344                         }
 345                         pfn += (1UL << page_owner->order) - 1;
 346 ext_put_continue:
 347                         page_ext_put(page_ext);
 348                 }
 349         }
 350
 351         /* Print counts */
 352         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 353         for (i = 0; i < MIGRATE_TYPES; i++)
 354                 seq_printf(m, "%12lu ", count[i]);
 355         seq_putc(m, '\n');
 356 }
 357
 358 /*
 359  * Looking for memcg information and print it out
 360  */
 361 static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret,
 362                                          struct page *page)
 363 {
 364 #ifdef CONFIG_MEMCG
 365         unsigned long memcg_data;
 366         struct mem_cgroup *memcg;
 367         bool online;
 368         char name[80];
 369
 370         rcu_read_lock();
 371         memcg_data = READ_ONCE(page->memcg_data);
 372         if (!memcg_data)
 373                 goto out_unlock;
 374
 375         if (memcg_data & MEMCG_DATA_OBJCGS)
 376                 ret += scnprintf(kbuf + ret, count - ret,
 377                                 "Slab cache page\n");
 378
 379         memcg = page_memcg_check(page);
 380         if (!memcg)
 381                 goto out_unlock;
 382
 383         online = (memcg->css.flags & CSS_ONLINE);
 384         cgroup_name(memcg->css.cgroup, name, sizeof(name));
 385         ret += scnprintf(kbuf + ret, count - ret,
 386                         "Charged %sto %smemcg %s\n",
 387                         PageMemcgKmem(page) ? "(via objcg) " : "",
 388                         online ? "" : "offline ",
 389                         name);
 390 out_unlock:
 391         rcu_read_unlock();
 392 #endif /* CONFIG_MEMCG */
 393
 394         return ret;
 395 }
 396
 397 static ssize_t
 398 print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 399                 struct page *page, struct page_owner *page_owner,
 400                 depot_stack_handle_t handle)
 401 {
 402         int ret, pageblock_mt, page_mt;
 403         char *kbuf;
 404
 405         count = min_t(size_t, count, PAGE_SIZE);
 406         kbuf = kmalloc(count, GFP_KERNEL);
 407         if (!kbuf)
 408                 return -ENOMEM;
 409
 410         ret = scnprintf(kbuf, count,
 411                         "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns, free_ts %llu ns\n",
 412                         page_owner->order, page_owner->gfp_mask,
 413                         &page_owner->gfp_mask, page_owner->pid,
 414                         page_owner->tgid, page_owner->comm,
 415                         page_owner->ts_nsec, page_owner->free_ts_nsec);
 416
 417         /* Print information relevant to grouping pages by mobility */
 418         pageblock_mt = get_pageblock_migratetype(page);
 419         page_mt  = gfp_migratetype(page_owner->gfp_mask);
 420         ret += scnprintf(kbuf + ret, count - ret,
 421                         "PFN 0x%lx type %s Block %lu type %s Flags %pGp\n",
 422                         pfn,
 423                         migratetype_names[page_mt],
 424                         pfn >> pageblock_order,
 425                         migratetype_names[pageblock_mt],
 426                         &page->flags);
 427
 428         ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0);
 429         if (ret >= count)
 430                 goto err;
 431
 432         if (page_owner->last_migrate_reason != -1) {
 433                 ret += scnprintf(kbuf + ret, count - ret,
 434                         "Page has been migrated, last migrate reason: %s\n",
 435                         migrate_reason_names[page_owner->last_migrate_reason]);
 436         }
 437
 438         ret = print_page_owner_memcg(kbuf, count, ret, page);
 439
 440         ret += snprintf(kbuf + ret, count - ret, "\n");
 441         if (ret >= count)
 442                 goto err;
 443
 444         if (copy_to_user(buf, kbuf, ret))
 445                 ret = -EFAULT;
 446
 447         kfree(kbuf);
 448         return ret;
 449
 450 err:
 451         kfree(kbuf);
 452         return -ENOMEM;
 453 }
 454
 455 void __dump_page_owner(const struct page *page)
 456 {
 457         struct page_ext *page_ext = page_ext_get((void *)page);
 458         struct page_owner *page_owner;
 459         depot_stack_handle_t handle;
 460         gfp_t gfp_mask;
 461         int mt;
 462
 463         if (unlikely(!page_ext)) {
 464                 pr_alert("There is not page extension available.\n");
 465                 return;
 466         }
 467
 468         page_owner = get_page_owner(page_ext);
 469         gfp_mask = page_owner->gfp_mask;
 470         mt = gfp_migratetype(gfp_mask);
 471
 472         if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
 473                 pr_alert("page_owner info is not present (never set?)\n");
 474                 page_ext_put(page_ext);
 475                 return;
 476         }
 477
 478         if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
 479                 pr_alert("page_owner tracks the page as allocated\n");
 480         else
 481                 pr_alert("page_owner tracks the page as freed\n");
 482
 483         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",
 484                  page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask,
 485                  page_owner->pid, page_owner->tgid, page_owner->comm,
 486                  page_owner->ts_nsec, page_owner->free_ts_nsec);
 487
 488         handle = READ_ONCE(page_owner->handle);
 489         if (!handle)
 490                 pr_alert("page_owner allocation stack trace missing\n");
 491         else
 492                 stack_depot_print(handle);
 493
 494         handle = READ_ONCE(page_owner->free_handle);
 495         if (!handle) {
 496                 pr_alert("page_owner free stack trace missing\n");
 497         } else {
 498                 pr_alert("page last free stack trace:\n");
 499                 stack_depot_print(handle);
 500         }
 501
 502         if (page_owner->last_migrate_reason != -1)
 503                 pr_alert("page has been migrated, last migrate reason: %s\n",
 504                         migrate_reason_names[page_owner->last_migrate_reason]);
 505         page_ext_put(page_ext);
 506 }
 507
 508 static ssize_t
 509 read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 510 {
 511         unsigned long pfn;
 512         struct page *page;
 513         struct page_ext *page_ext;
 514         struct page_owner *page_owner;
 515         depot_stack_handle_t handle;
 516
 517         if (!static_branch_unlikely(&page_owner_inited))
 518                 return -EINVAL;
 519
 520         page = NULL;
 521         if (*ppos == 0)
 522                 pfn = min_low_pfn;
 523         else
 524                 pfn = *ppos;
 525         /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
 526         while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
 527                 pfn++;
 528
 529         /* Find an allocated page */
 530         for (; pfn < max_pfn; pfn++) {
 531                 /*
 532                  * This temporary page_owner is required so
 533                  * that we can avoid the context switches while holding
 534                  * the rcu lock and copying the page owner information to
 535                  * user through copy_to_user() or GFP_KERNEL allocations.
 536                  */
 537                 struct page_owner page_owner_tmp;
 538
 539                 /*
 540                  * If the new page is in a new MAX_ORDER_NR_PAGES area,
 541                  * validate the area as existing, skip it if not
 542                  */
 543                 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
 544                         pfn += MAX_ORDER_NR_PAGES - 1;
 545                         continue;
 546                 }
 547
 548                 page = pfn_to_page(pfn);
 549                 if (PageBuddy(page)) {
 550                         unsigned long freepage_order = buddy_order_unsafe(page);
 551
 552                         if (freepage_order <= MAX_ORDER)
 553                                 pfn += (1UL << freepage_order) - 1;
 554                         continue;
 555                 }
 556
 557                 page_ext = page_ext_get(page);
 558                 if (unlikely(!page_ext))
 559                         continue;
 560
 561                 /*
 562                  * Some pages could be missed by concurrent allocation or free,
 563                  * because we don't hold the zone lock.
 564                  */
 565                 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
 566                         goto ext_put_continue;
 567
 568                 /*
 569                  * Although we do have the info about past allocation of free
 570                  * pages, it's not relevant for current memory usage.
 571                  */
 572                 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
 573                         goto ext_put_continue;
 574
 575                 page_owner = get_page_owner(page_ext);
 576
 577                 /*
 578                  * Don't print "tail" pages of high-order allocations as that
 579                  * would inflate the stats.
 580                  */
 581                 if (!IS_ALIGNED(pfn, 1 << page_owner->order))
 582                         goto ext_put_continue;
 583
 584                 /*
 585                  * Access to page_ext->handle isn't synchronous so we should
 586                  * be careful to access it.
 587                  */
 588                 handle = READ_ONCE(page_owner->handle);
 589                 if (!handle)
 590                         goto ext_put_continue;
 591
 592                 /* Record the next PFN to read in the file offset */
 593                 *ppos = pfn + 1;
 594
 595                 page_owner_tmp = *page_owner;
 596                 page_ext_put(page_ext);
 597                 return print_page_owner(buf, count, pfn, page,
 598                                 &page_owner_tmp, handle);
 599 ext_put_continue:
 600                 page_ext_put(page_ext);
 601         }
 602
 603         return 0;
 604 }
 605
 606 static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig)
 607 {
 608         switch (orig) {
 609         case SEEK_SET:
 610                 file->f_pos = offset;
 611                 break;
 612         case SEEK_CUR:
 613                 file->f_pos += offset;
 614                 break;
 615         default:
 616                 return -EINVAL;
 617         }
 618         return file->f_pos;
 619 }
 620
 621 static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
 622 {
 623         unsigned long pfn = zone->zone_start_pfn;
 624         unsigned long end_pfn = zone_end_pfn(zone);
 625         unsigned long count = 0;
 626
 627         /*
 628          * Walk the zone in pageblock_nr_pages steps. If a page block spans
 629          * a zone boundary, it will be double counted between zones. This does
 630          * not matter as the mixed block count will still be correct
 631          */
 632         for (; pfn < end_pfn; ) {
 633                 unsigned long block_end_pfn;
 634
 635                 if (!pfn_valid(pfn)) {
 636                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
 637                         continue;
 638                 }
 639
 640                 block_end_pfn = pageblock_end_pfn(pfn);
 641                 block_end_pfn = min(block_end_pfn, end_pfn);
 642
 643                 for (; pfn < block_end_pfn; pfn++) {
 644                         struct page *page = pfn_to_page(pfn);
 645                         struct page_ext *page_ext;
 646
 647                         if (page_zone(page) != zone)
 648                                 continue;
 649
 650                         /*
 651                          * To avoid having to grab zone->lock, be a little
 652                          * careful when reading buddy page order. The only
 653                          * danger is that we skip too much and potentially miss
 654                          * some early allocated pages, which is better than
 655                          * heavy lock contention.
 656                          */
 657                         if (PageBuddy(page)) {
 658                                 unsigned long order = buddy_order_unsafe(page);
 659
 660                                 if (order > 0 && order <= MAX_ORDER)
 661                                         pfn += (1UL << order) - 1;
 662                                 continue;
 663                         }
 664
 665                         if (PageReserved(page))
 666                                 continue;
 667
 668                         page_ext = page_ext_get(page);
 669                         if (unlikely(!page_ext))
 670                                 continue;
 671
 672                         /* Maybe overlapping zone */
 673                         if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
 674                                 goto ext_put_continue;
 675
 676                         /* Found early allocated page */
 677                         __set_page_owner_handle(page_ext, early_handle,
 678                                                 0, 0);
 679                         count++;
 680 ext_put_continue:
 681                         page_ext_put(page_ext);
 682                 }
 683                 cond_resched();
 684         }
 685
 686         pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
 687                 pgdat->node_id, zone->name, count);
 688 }
 689
 690 static void init_zones_in_node(pg_data_t *pgdat)
 691 {
 692         struct zone *zone;
 693         struct zone *node_zones = pgdat->node_zones;
 694
 695         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 696                 if (!populated_zone(zone))
 697                         continue;
 698
 699                 init_pages_in_zone(pgdat, zone);
 700         }
 701 }
 702
 703 static void init_early_allocated_pages(void)
 704 {
 705         pg_data_t *pgdat;
 706
 707         for_each_online_pgdat(pgdat)
 708                 init_zones_in_node(pgdat);
 709 }
 710
 711 static const struct file_operations proc_page_owner_operations = {
 712         .read           = read_page_owner,
 713         .llseek         = lseek_page_owner,
 714 };
 715
 716 static int __init pageowner_init(void)
 717 {
 718         if (!static_branch_unlikely(&page_owner_inited)) {
 719                 pr_info("page_owner is disabled\n");
 720                 return 0;
 721         }
 722
 723         debugfs_create_file("page_owner", 0400, NULL, NULL,
 724                             &proc_page_owner_operations);
 725
 726         return 0;
 727 }
 728 late_initcall(pageowner_init)