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         pid_t free_pid;
  36         pid_t free_tgid;
  37 };
  38
  39 static bool page_owner_enabled __initdata;
  40 DEFINE_STATIC_KEY_FALSE(page_owner_inited);
  41
  42 static depot_stack_handle_t dummy_handle;
  43 static depot_stack_handle_t failure_handle;
  44 static depot_stack_handle_t early_handle;
  45
  46 static void init_early_allocated_pages(void);
  47
  48 static int __init early_page_owner_param(char *buf)
  49 {
  50         int ret = kstrtobool(buf, &page_owner_enabled);
  51
  52         if (page_owner_enabled)
  53                 stack_depot_request_early_init();
  54
  55         return ret;
  56 }
  57 early_param("page_owner", early_page_owner_param);
  58
  59 static __init bool need_page_owner(void)
  60 {
  61         return page_owner_enabled;
  62 }
  63
  64 static __always_inline depot_stack_handle_t create_dummy_stack(void)
  65 {
  66         unsigned long entries[4];
  67         unsigned int nr_entries;
  68
  69         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
  70         return stack_depot_save(entries, nr_entries, GFP_KERNEL);
  71 }
  72
  73 static noinline void register_dummy_stack(void)
  74 {
  75         dummy_handle = create_dummy_stack();
  76 }
  77
  78 static noinline void register_failure_stack(void)
  79 {
  80         failure_handle = create_dummy_stack();
  81 }
  82
  83 static noinline void register_early_stack(void)
  84 {
  85         early_handle = create_dummy_stack();
  86 }
  87
  88 static __init void init_page_owner(void)
  89 {
  90         if (!page_owner_enabled)
  91                 return;
  92
  93         register_dummy_stack();
  94         register_failure_stack();
  95         register_early_stack();
  96         static_branch_enable(&page_owner_inited);
  97         init_early_allocated_pages();
  98 }
  99
 100 struct page_ext_operations page_owner_ops = {
 101         .size = sizeof(struct page_owner),
 102         .need = need_page_owner,
 103         .init = init_page_owner,
 104         .need_shared_flags = true,
 105 };
 106
 107 static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
 108 {
 109         return page_ext_data(page_ext, &page_owner_ops);
 110 }
 111
 112 static noinline depot_stack_handle_t save_stack(gfp_t flags)
 113 {
 114         unsigned long entries[PAGE_OWNER_STACK_DEPTH];
 115         depot_stack_handle_t handle;
 116         unsigned int nr_entries;
 117
 118         /*
 119          * Avoid recursion.
 120          *
 121          * Sometimes page metadata allocation tracking requires more
 122          * memory to be allocated:
 123          * - when new stack trace is saved to stack depot
 124          */
 125         if (current->in_page_owner)
 126                 return dummy_handle;
 127         current->in_page_owner = 1;
 128
 129         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2);
 130         handle = stack_depot_save(entries, nr_entries, flags);
 131         if (!handle)
 132                 handle = failure_handle;
 133
 134         current->in_page_owner = 0;
 135         return handle;
 136 }
 137
 138 void __reset_page_owner(struct page *page, unsigned short order)
 139 {
 140         int i;
 141         struct page_ext *page_ext;
 142         depot_stack_handle_t handle;
 143         struct page_owner *page_owner;
 144         u64 free_ts_nsec = local_clock();
 145
 146         page_ext = page_ext_get(page);
 147         if (unlikely(!page_ext))
 148                 return;
 149
 150         handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
 151         for (i = 0; i < (1 << order); i++) {
 152                 __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
 153                 page_owner = get_page_owner(page_ext);
 154                 page_owner->free_handle = handle;
 155                 page_owner->free_ts_nsec = free_ts_nsec;
 156                 page_owner->free_pid = current->pid;
 157                 page_owner->free_tgid = current->tgid;
 158                 page_ext = page_ext_next(page_ext);
 159         }
 160         page_ext_put(page_ext);
 161 }
 162
 163 static inline void __set_page_owner_handle(struct page_ext *page_ext,
 164                                         depot_stack_handle_t handle,
 165                                         unsigned short order, gfp_t gfp_mask)
 166 {
 167         struct page_owner *page_owner;
 168         int i;
 169         u64 ts_nsec = local_clock();
 170
 171         for (i = 0; i < (1 << order); i++) {
 172                 page_owner = get_page_owner(page_ext);
 173                 page_owner->handle = handle;
 174                 page_owner->order = order;
 175                 page_owner->gfp_mask = gfp_mask;
 176                 page_owner->last_migrate_reason = -1;
 177                 page_owner->pid = current->pid;
 178                 page_owner->tgid = current->tgid;
 179                 page_owner->ts_nsec = ts_nsec;
 180                 strscpy(page_owner->comm, current->comm,
 181                         sizeof(page_owner->comm));
 182                 __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
 183                 __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
 184
 185                 page_ext = page_ext_next(page_ext);
 186         }
 187 }
 188
 189 noinline void __set_page_owner(struct page *page, unsigned short order,
 190                                         gfp_t gfp_mask)
 191 {
 192         struct page_ext *page_ext;
 193         depot_stack_handle_t handle;
 194
 195         handle = save_stack(gfp_mask);
 196
 197         page_ext = page_ext_get(page);
 198         if (unlikely(!page_ext))
 199                 return;
 200         __set_page_owner_handle(page_ext, handle, order, gfp_mask);
 201         page_ext_put(page_ext);
 202 }
 203
 204 void __set_page_owner_migrate_reason(struct page *page, int reason)
 205 {
 206         struct page_ext *page_ext = page_ext_get(page);
 207         struct page_owner *page_owner;
 208
 209         if (unlikely(!page_ext))
 210                 return;
 211
 212         page_owner = get_page_owner(page_ext);
 213         page_owner->last_migrate_reason = reason;
 214         page_ext_put(page_ext);
 215 }
 216
 217 void __split_page_owner(struct page *page, unsigned int nr)
 218 {
 219         int i;
 220         struct page_ext *page_ext = page_ext_get(page);
 221         struct page_owner *page_owner;
 222
 223         if (unlikely(!page_ext))
 224                 return;
 225
 226         for (i = 0; i < nr; i++) {
 227                 page_owner = get_page_owner(page_ext);
 228                 page_owner->order = 0;
 229                 page_ext = page_ext_next(page_ext);
 230         }
 231         page_ext_put(page_ext);
 232 }
 233
 234 void __folio_copy_owner(struct folio *newfolio, struct folio *old)
 235 {
 236         struct page_ext *old_ext;
 237         struct page_ext *new_ext;
 238         struct page_owner *old_page_owner, *new_page_owner;
 239
 240         old_ext = page_ext_get(&old->page);
 241         if (unlikely(!old_ext))
 242                 return;
 243
 244         new_ext = page_ext_get(&newfolio->page);
 245         if (unlikely(!new_ext)) {
 246                 page_ext_put(old_ext);
 247                 return;
 248         }
 249
 250         old_page_owner = get_page_owner(old_ext);
 251         new_page_owner = get_page_owner(new_ext);
 252         new_page_owner->order = old_page_owner->order;
 253         new_page_owner->gfp_mask = old_page_owner->gfp_mask;
 254         new_page_owner->last_migrate_reason =
 255                 old_page_owner->last_migrate_reason;
 256         new_page_owner->handle = old_page_owner->handle;
 257         new_page_owner->pid = old_page_owner->pid;
 258         new_page_owner->tgid = old_page_owner->tgid;
 259         new_page_owner->free_pid = old_page_owner->free_pid;
 260         new_page_owner->free_tgid = old_page_owner->free_tgid;
 261         new_page_owner->ts_nsec = old_page_owner->ts_nsec;
 262         new_page_owner->free_ts_nsec = old_page_owner->ts_nsec;
 263         strcpy(new_page_owner->comm, old_page_owner->comm);
 264
 265         /*
 266          * We don't clear the bit on the old folio as it's going to be freed
 267          * after migration. Until then, the info can be useful in case of
 268          * a bug, and the overall stats will be off a bit only temporarily.
 269          * Also, migrate_misplaced_transhuge_page() can still fail the
 270          * migration and then we want the old folio to retain the info. But
 271          * in that case we also don't need to explicitly clear the info from
 272          * the new page, which will be freed.
 273          */
 274         __set_bit(PAGE_EXT_OWNER, &new_ext->flags);
 275         __set_bit(PAGE_EXT_OWNER_ALLOCATED, &new_ext->flags);
 276         page_ext_put(new_ext);
 277         page_ext_put(old_ext);
 278 }
 279
 280 void pagetypeinfo_showmixedcount_print(struct seq_file *m,
 281                                        pg_data_t *pgdat, struct zone *zone)
 282 {
 283         struct page *page;
 284         struct page_ext *page_ext;
 285         struct page_owner *page_owner;
 286         unsigned long pfn, block_end_pfn;
 287         unsigned long end_pfn = zone_end_pfn(zone);
 288         unsigned long count[MIGRATE_TYPES] = { 0, };
 289         int pageblock_mt, page_mt;
 290         int i;
 291
 292         /* Scan block by block. First and last block may be incomplete */
 293         pfn = zone->zone_start_pfn;
 294
 295         /*
 296          * Walk the zone in pageblock_nr_pages steps. If a page block spans
 297          * a zone boundary, it will be double counted between zones. This does
 298          * not matter as the mixed block count will still be correct
 299          */
 300         for (; pfn < end_pfn; ) {
 301                 page = pfn_to_online_page(pfn);
 302                 if (!page) {
 303                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
 304                         continue;
 305                 }
 306
 307                 block_end_pfn = pageblock_end_pfn(pfn);
 308                 block_end_pfn = min(block_end_pfn, end_pfn);
 309
 310                 pageblock_mt = get_pageblock_migratetype(page);
 311
 312                 for (; pfn < block_end_pfn; pfn++) {
 313                         /* The pageblock is online, no need to recheck. */
 314                         page = pfn_to_page(pfn);
 315
 316                         if (page_zone(page) != zone)
 317                                 continue;
 318
 319                         if (PageBuddy(page)) {
 320                                 unsigned long freepage_order;
 321
 322                                 freepage_order = buddy_order_unsafe(page);
 323                                 if (freepage_order <= MAX_PAGE_ORDER)
 324                                         pfn += (1UL << freepage_order) - 1;
 325                                 continue;
 326                         }
 327
 328                         if (PageReserved(page))
 329                                 continue;
 330
 331                         page_ext = page_ext_get(page);
 332                         if (unlikely(!page_ext))
 333                                 continue;
 334
 335                         if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
 336                                 goto ext_put_continue;
 337
 338                         page_owner = get_page_owner(page_ext);
 339                         page_mt = gfp_migratetype(page_owner->gfp_mask);
 340                         if (pageblock_mt != page_mt) {
 341                                 if (is_migrate_cma(pageblock_mt))
 342                                         count[MIGRATE_MOVABLE]++;
 343                                 else
 344                                         count[pageblock_mt]++;
 345
 346                                 pfn = block_end_pfn;
 347                                 page_ext_put(page_ext);
 348                                 break;
 349                         }
 350                         pfn += (1UL << page_owner->order) - 1;
 351 ext_put_continue:
 352                         page_ext_put(page_ext);
 353                 }
 354         }
 355
 356         /* Print counts */
 357         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 358         for (i = 0; i < MIGRATE_TYPES; i++)
 359                 seq_printf(m, "%12lu ", count[i]);
 360         seq_putc(m, '\n');
 361 }
 362
 363 /*
 364  * Looking for memcg information and print it out
 365  */
 366 static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret,
 367                                          struct page *page)
 368 {
 369 #ifdef CONFIG_MEMCG
 370         unsigned long memcg_data;
 371         struct mem_cgroup *memcg;
 372         bool online;
 373         char name[80];
 374
 375         rcu_read_lock();
 376         memcg_data = READ_ONCE(page->memcg_data);
 377         if (!memcg_data)
 378                 goto out_unlock;
 379
 380         if (memcg_data & MEMCG_DATA_OBJCGS)
 381                 ret += scnprintf(kbuf + ret, count - ret,
 382                                 "Slab cache page\n");
 383
 384         memcg = page_memcg_check(page);
 385         if (!memcg)
 386                 goto out_unlock;
 387
 388         online = (memcg->css.flags & CSS_ONLINE);
 389         cgroup_name(memcg->css.cgroup, name, sizeof(name));
 390         ret += scnprintf(kbuf + ret, count - ret,
 391                         "Charged %sto %smemcg %s\n",
 392                         PageMemcgKmem(page) ? "(via objcg) " : "",
 393                         online ? "" : "offline ",
 394                         name);
 395 out_unlock:
 396         rcu_read_unlock();
 397 #endif /* CONFIG_MEMCG */
 398
 399         return ret;
 400 }
 401
 402 static ssize_t
 403 print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 404                 struct page *page, struct page_owner *page_owner,
 405                 depot_stack_handle_t handle)
 406 {
 407         int ret, pageblock_mt, page_mt;
 408         char *kbuf;
 409
 410         count = min_t(size_t, count, PAGE_SIZE);
 411         kbuf = kmalloc(count, GFP_KERNEL);
 412         if (!kbuf)
 413                 return -ENOMEM;
 414
 415         ret = scnprintf(kbuf, count,
 416                         "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns\n",
 417                         page_owner->order, page_owner->gfp_mask,
 418                         &page_owner->gfp_mask, page_owner->pid,
 419                         page_owner->tgid, page_owner->comm,
 420                         page_owner->ts_nsec);
 421
 422         /* Print information relevant to grouping pages by mobility */
 423         pageblock_mt = get_pageblock_migratetype(page);
 424         page_mt  = gfp_migratetype(page_owner->gfp_mask);
 425         ret += scnprintf(kbuf + ret, count - ret,
 426                         "PFN 0x%lx type %s Block %lu type %s Flags %pGp\n",
 427                         pfn,
 428                         migratetype_names[page_mt],
 429                         pfn >> pageblock_order,
 430                         migratetype_names[pageblock_mt],
 431                         &page->flags);
 432
 433         ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0);
 434         if (ret >= count)
 435                 goto err;
 436
 437         if (page_owner->last_migrate_reason != -1) {
 438                 ret += scnprintf(kbuf + ret, count - ret,
 439                         "Page has been migrated, last migrate reason: %s\n",
 440                         migrate_reason_names[page_owner->last_migrate_reason]);
 441         }
 442
 443         ret = print_page_owner_memcg(kbuf, count, ret, page);
 444
 445         ret += snprintf(kbuf + ret, count - ret, "\n");
 446         if (ret >= count)
 447                 goto err;
 448
 449         if (copy_to_user(buf, kbuf, ret))
 450                 ret = -EFAULT;
 451
 452         kfree(kbuf);
 453         return ret;
 454
 455 err:
 456         kfree(kbuf);
 457         return -ENOMEM;
 458 }
 459
 460 void __dump_page_owner(const struct page *page)
 461 {
 462         struct page_ext *page_ext = page_ext_get((void *)page);
 463         struct page_owner *page_owner;
 464         depot_stack_handle_t handle;
 465         gfp_t gfp_mask;
 466         int mt;
 467
 468         if (unlikely(!page_ext)) {
 469                 pr_alert("There is not page extension available.\n");
 470                 return;
 471         }
 472
 473         page_owner = get_page_owner(page_ext);
 474         gfp_mask = page_owner->gfp_mask;
 475         mt = gfp_migratetype(gfp_mask);
 476
 477         if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
 478                 pr_alert("page_owner info is not present (never set?)\n");
 479                 page_ext_put(page_ext);
 480                 return;
 481         }
 482
 483         if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
 484                 pr_alert("page_owner tracks the page as allocated\n");
 485         else
 486                 pr_alert("page_owner tracks the page as freed\n");
 487
 488         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",
 489                  page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask,
 490                  page_owner->pid, page_owner->tgid, page_owner->comm,
 491                  page_owner->ts_nsec, page_owner->free_ts_nsec);
 492
 493         handle = READ_ONCE(page_owner->handle);
 494         if (!handle)
 495                 pr_alert("page_owner allocation stack trace missing\n");
 496         else
 497                 stack_depot_print(handle);
 498
 499         handle = READ_ONCE(page_owner->free_handle);
 500         if (!handle) {
 501                 pr_alert("page_owner free stack trace missing\n");
 502         } else {
 503                 pr_alert("page last free pid %d tgid %d stack trace:\n",
 504                           page_owner->free_pid, page_owner->free_tgid);
 505                 stack_depot_print(handle);
 506         }
 507
 508         if (page_owner->last_migrate_reason != -1)
 509                 pr_alert("page has been migrated, last migrate reason: %s\n",
 510                         migrate_reason_names[page_owner->last_migrate_reason]);
 511         page_ext_put(page_ext);
 512 }
 513
 514 static ssize_t
 515 read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 516 {
 517         unsigned long pfn;
 518         struct page *page;
 519         struct page_ext *page_ext;
 520         struct page_owner *page_owner;
 521         depot_stack_handle_t handle;
 522
 523         if (!static_branch_unlikely(&page_owner_inited))
 524                 return -EINVAL;
 525
 526         page = NULL;
 527         if (*ppos == 0)
 528                 pfn = min_low_pfn;
 529         else
 530                 pfn = *ppos;
 531         /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
 532         while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
 533                 pfn++;
 534
 535         /* Find an allocated page */
 536         for (; pfn < max_pfn; pfn++) {
 537                 /*
 538                  * This temporary page_owner is required so
 539                  * that we can avoid the context switches while holding
 540                  * the rcu lock and copying the page owner information to
 541                  * user through copy_to_user() or GFP_KERNEL allocations.
 542                  */
 543                 struct page_owner page_owner_tmp;
 544
 545                 /*
 546                  * If the new page is in a new MAX_ORDER_NR_PAGES area,
 547                  * validate the area as existing, skip it if not
 548                  */
 549                 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
 550                         pfn += MAX_ORDER_NR_PAGES - 1;
 551                         continue;
 552                 }
 553
 554                 page = pfn_to_page(pfn);
 555                 if (PageBuddy(page)) {
 556                         unsigned long freepage_order = buddy_order_unsafe(page);
 557
 558                         if (freepage_order <= MAX_PAGE_ORDER)
 559                                 pfn += (1UL << freepage_order) - 1;
 560                         continue;
 561                 }
 562
 563                 page_ext = page_ext_get(page);
 564                 if (unlikely(!page_ext))
 565                         continue;
 566
 567                 /*
 568                  * Some pages could be missed by concurrent allocation or free,
 569                  * because we don't hold the zone lock.
 570                  */
 571                 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
 572                         goto ext_put_continue;
 573
 574                 /*
 575                  * Although we do have the info about past allocation of free
 576                  * pages, it's not relevant for current memory usage.
 577                  */
 578                 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
 579                         goto ext_put_continue;
 580
 581                 page_owner = get_page_owner(page_ext);
 582
 583                 /*
 584                  * Don't print "tail" pages of high-order allocations as that
 585                  * would inflate the stats.
 586                  */
 587                 if (!IS_ALIGNED(pfn, 1 << page_owner->order))
 588                         goto ext_put_continue;
 589
 590                 /*
 591                  * Access to page_ext->handle isn't synchronous so we should
 592                  * be careful to access it.
 593                  */
 594                 handle = READ_ONCE(page_owner->handle);
 595                 if (!handle)
 596                         goto ext_put_continue;
 597
 598                 /* Record the next PFN to read in the file offset */
 599                 *ppos = pfn + 1;
 600
 601                 page_owner_tmp = *page_owner;
 602                 page_ext_put(page_ext);
 603                 return print_page_owner(buf, count, pfn, page,
 604                                 &page_owner_tmp, handle);
 605 ext_put_continue:
 606                 page_ext_put(page_ext);
 607         }
 608
 609         return 0;
 610 }
 611
 612 static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig)
 613 {
 614         switch (orig) {
 615         case SEEK_SET:
 616                 file->f_pos = offset;
 617                 break;
 618         case SEEK_CUR:
 619                 file->f_pos += offset;
 620                 break;
 621         default:
 622                 return -EINVAL;
 623         }
 624         return file->f_pos;
 625 }
 626
 627 static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
 628 {
 629         unsigned long pfn = zone->zone_start_pfn;
 630         unsigned long end_pfn = zone_end_pfn(zone);
 631         unsigned long count = 0;
 632
 633         /*
 634          * Walk the zone in pageblock_nr_pages steps. If a page block spans
 635          * a zone boundary, it will be double counted between zones. This does
 636          * not matter as the mixed block count will still be correct
 637          */
 638         for (; pfn < end_pfn; ) {
 639                 unsigned long block_end_pfn;
 640
 641                 if (!pfn_valid(pfn)) {
 642                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
 643                         continue;
 644                 }
 645
 646                 block_end_pfn = pageblock_end_pfn(pfn);
 647                 block_end_pfn = min(block_end_pfn, end_pfn);
 648
 649                 for (; pfn < block_end_pfn; pfn++) {
 650                         struct page *page = pfn_to_page(pfn);
 651                         struct page_ext *page_ext;
 652
 653                         if (page_zone(page) != zone)
 654                                 continue;
 655
 656                         /*
 657                          * To avoid having to grab zone->lock, be a little
 658                          * careful when reading buddy page order. The only
 659                          * danger is that we skip too much and potentially miss
 660                          * some early allocated pages, which is better than
 661                          * heavy lock contention.
 662                          */
 663                         if (PageBuddy(page)) {
 664                                 unsigned long order = buddy_order_unsafe(page);
 665
 666                                 if (order > 0 && order <= MAX_PAGE_ORDER)
 667                                         pfn += (1UL << order) - 1;
 668                                 continue;
 669                         }
 670
 671                         if (PageReserved(page))
 672                                 continue;
 673
 674                         page_ext = page_ext_get(page);
 675                         if (unlikely(!page_ext))
 676                                 continue;
 677
 678                         /* Maybe overlapping zone */
 679                         if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
 680                                 goto ext_put_continue;
 681
 682                         /* Found early allocated page */
 683                         __set_page_owner_handle(page_ext, early_handle,
 684                                                 0, 0);
 685                         count++;
 686 ext_put_continue:
 687                         page_ext_put(page_ext);
 688                 }
 689                 cond_resched();
 690         }
 691
 692         pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
 693                 pgdat->node_id, zone->name, count);
 694 }
 695
 696 static void init_zones_in_node(pg_data_t *pgdat)
 697 {
 698         struct zone *zone;
 699         struct zone *node_zones = pgdat->node_zones;
 700
 701         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 702                 if (!populated_zone(zone))
 703                         continue;
 704
 705                 init_pages_in_zone(pgdat, zone);
 706         }
 707 }
 708
 709 static void init_early_allocated_pages(void)
 710 {
 711         pg_data_t *pgdat;
 712
 713         for_each_online_pgdat(pgdat)
 714                 init_zones_in_node(pgdat);
 715 }
 716
 717 static const struct file_operations proc_page_owner_operations = {
 718         .read           = read_page_owner,
 719         .llseek         = lseek_page_owner,
 720 };
 721
 722 static int __init pageowner_init(void)
 723 {
 724         if (!static_branch_unlikely(&page_owner_inited)) {
 725                 pr_info("page_owner is disabled\n");
 726                 return 0;
 727         }
 728
 729         debugfs_create_file("page_owner", 0400, NULL, NULL,
 730                             &proc_page_owner_operations);
 731
 732         return 0;
 733 }
 734 late_initcall(pageowner_init)