tools/testing/selftests/vm/khugepaged.c

   1 #define _GNU_SOURCE
   2 #include <fcntl.h>
   3 #include <limits.h>
   4 #include <signal.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <stdbool.h>
   8 #include <string.h>
   9 #include <unistd.h>
  10
  11 #include <sys/mman.h>
  12 #include <sys/wait.h>
  13
  14 #ifndef MADV_PAGEOUT
  15 #define MADV_PAGEOUT 21
  16 #endif
  17
  18 #define BASE_ADDR ((void *)(1UL << 30))
  19 static unsigned long hpage_pmd_size;
  20 static unsigned long page_size;
  21 static int hpage_pmd_nr;
  22
  23 #define THP_SYSFS "/sys/kernel/mm/transparent_hugepage/"
  24 #define PID_SMAPS "/proc/self/smaps"
  25
  26 enum thp_enabled {
  27         THP_ALWAYS,
  28         THP_MADVISE,
  29         THP_NEVER,
  30 };
  31
  32 static const char *thp_enabled_strings[] = {
  33         "always",
  34         "madvise",
  35         "never",
  36         NULL
  37 };
  38
  39 enum thp_defrag {
  40         THP_DEFRAG_ALWAYS,
  41         THP_DEFRAG_DEFER,
  42         THP_DEFRAG_DEFER_MADVISE,
  43         THP_DEFRAG_MADVISE,
  44         THP_DEFRAG_NEVER,
  45 };
  46
  47 static const char *thp_defrag_strings[] = {
  48         "always",
  49         "defer",
  50         "defer+madvise",
  51         "madvise",
  52         "never",
  53         NULL
  54 };
  55
  56 enum shmem_enabled {
  57         SHMEM_ALWAYS,
  58         SHMEM_WITHIN_SIZE,
  59         SHMEM_ADVISE,
  60         SHMEM_NEVER,
  61         SHMEM_DENY,
  62         SHMEM_FORCE,
  63 };
  64
  65 static const char *shmem_enabled_strings[] = {
  66         "always",
  67         "within_size",
  68         "advise",
  69         "never",
  70         "deny",
  71         "force",
  72         NULL
  73 };
  74
  75 struct khugepaged_settings {
  76         bool defrag;
  77         unsigned int alloc_sleep_millisecs;
  78         unsigned int scan_sleep_millisecs;
  79         unsigned int max_ptes_none;
  80         unsigned int max_ptes_swap;
  81         unsigned int max_ptes_shared;
  82         unsigned long pages_to_scan;
  83 };
  84
  85 struct settings {
  86         enum thp_enabled thp_enabled;
  87         enum thp_defrag thp_defrag;
  88         enum shmem_enabled shmem_enabled;
  89         bool debug_cow;
  90         bool use_zero_page;
  91         struct khugepaged_settings khugepaged;
  92 };
  93
  94 static struct settings default_settings = {
  95         .thp_enabled = THP_MADVISE,
  96         .thp_defrag = THP_DEFRAG_ALWAYS,
  97         .shmem_enabled = SHMEM_NEVER,
  98         .debug_cow = 0,
  99         .use_zero_page = 0,
 100         .khugepaged = {
 101                 .defrag = 1,
 102                 .alloc_sleep_millisecs = 10,
 103                 .scan_sleep_millisecs = 10,
 104         },
 105 };
 106
 107 static struct settings saved_settings;
 108 static bool skip_settings_restore;
 109
 110 static int exit_status;
 111
 112 static void success(const char *msg)
 113 {
 114         printf(" \e[32m%s\e[0m\n", msg);
 115 }
 116
 117 static void fail(const char *msg)
 118 {
 119         printf(" \e[31m%s\e[0m\n", msg);
 120         exit_status++;
 121 }
 122
 123 static int read_file(const char *path, char *buf, size_t buflen)
 124 {
 125         int fd;
 126         ssize_t numread;
 127
 128         fd = open(path, O_RDONLY);
 129         if (fd == -1)
 130                 return 0;
 131
 132         numread = read(fd, buf, buflen - 1);
 133         if (numread < 1) {
 134                 close(fd);
 135                 return 0;
 136         }
 137
 138         buf[numread] = '\0';
 139         close(fd);
 140
 141         return (unsigned int) numread;
 142 }
 143
 144 static int write_file(const char *path, const char *buf, size_t buflen)
 145 {
 146         int fd;
 147         ssize_t numwritten;
 148
 149         fd = open(path, O_WRONLY);
 150         if (fd == -1)
 151                 return 0;
 152
 153         numwritten = write(fd, buf, buflen - 1);
 154         close(fd);
 155         if (numwritten < 1)
 156                 return 0;
 157
 158         return (unsigned int) numwritten;
 159 }
 160
 161 static int read_string(const char *name, const char *strings[])
 162 {
 163         char path[PATH_MAX];
 164         char buf[256];
 165         char *c;
 166         int ret;
 167
 168         ret = snprintf(path, PATH_MAX, THP_SYSFS "%s", name);
 169         if (ret >= PATH_MAX) {
 170                 printf("%s: Pathname is too long\n", __func__);
 171                 exit(EXIT_FAILURE);
 172         }
 173
 174         if (!read_file(path, buf, sizeof(buf))) {
 175                 perror(path);
 176                 exit(EXIT_FAILURE);
 177         }
 178
 179         c = strchr(buf, '[');
 180         if (!c) {
 181                 printf("%s: Parse failure\n", __func__);
 182                 exit(EXIT_FAILURE);
 183         }
 184
 185         c++;
 186         memmove(buf, c, sizeof(buf) - (c - buf));
 187
 188         c = strchr(buf, ']');
 189         if (!c) {
 190                 printf("%s: Parse failure\n", __func__);
 191                 exit(EXIT_FAILURE);
 192         }
 193         *c = '\0';
 194
 195         ret = 0;
 196         while (strings[ret]) {
 197                 if (!strcmp(strings[ret], buf))
 198                         return ret;
 199                 ret++;
 200         }
 201
 202         printf("Failed to parse %s\n", name);
 203         exit(EXIT_FAILURE);
 204 }
 205
 206 static void write_string(const char *name, const char *val)
 207 {
 208         char path[PATH_MAX];
 209         int ret;
 210
 211         ret = snprintf(path, PATH_MAX, THP_SYSFS "%s", name);
 212         if (ret >= PATH_MAX) {
 213                 printf("%s: Pathname is too long\n", __func__);
 214                 exit(EXIT_FAILURE);
 215         }
 216
 217         if (!write_file(path, val, strlen(val) + 1)) {
 218                 perror(path);
 219                 exit(EXIT_FAILURE);
 220         }
 221 }
 222
 223 static const unsigned long read_num(const char *name)
 224 {
 225         char path[PATH_MAX];
 226         char buf[21];
 227         int ret;
 228
 229         ret = snprintf(path, PATH_MAX, THP_SYSFS "%s", name);
 230         if (ret >= PATH_MAX) {
 231                 printf("%s: Pathname is too long\n", __func__);
 232                 exit(EXIT_FAILURE);
 233         }
 234
 235         ret = read_file(path, buf, sizeof(buf));
 236         if (ret < 0) {
 237                 perror("read_file(read_num)");
 238                 exit(EXIT_FAILURE);
 239         }
 240
 241         return strtoul(buf, NULL, 10);
 242 }
 243
 244 static void write_num(const char *name, unsigned long num)
 245 {
 246         char path[PATH_MAX];
 247         char buf[21];
 248         int ret;
 249
 250         ret = snprintf(path, PATH_MAX, THP_SYSFS "%s", name);
 251         if (ret >= PATH_MAX) {
 252                 printf("%s: Pathname is too long\n", __func__);
 253                 exit(EXIT_FAILURE);
 254         }
 255
 256         sprintf(buf, "%ld", num);
 257         if (!write_file(path, buf, strlen(buf) + 1)) {
 258                 perror(path);
 259                 exit(EXIT_FAILURE);
 260         }
 261 }
 262
 263 static void write_settings(struct settings *settings)
 264 {
 265         struct khugepaged_settings *khugepaged = &settings->khugepaged;
 266
 267         write_string("enabled", thp_enabled_strings[settings->thp_enabled]);
 268         write_string("defrag", thp_defrag_strings[settings->thp_defrag]);
 269         write_string("shmem_enabled",
 270                         shmem_enabled_strings[settings->shmem_enabled]);
 271         write_num("debug_cow", settings->debug_cow);
 272         write_num("use_zero_page", settings->use_zero_page);
 273
 274         write_num("khugepaged/defrag", khugepaged->defrag);
 275         write_num("khugepaged/alloc_sleep_millisecs",
 276                         khugepaged->alloc_sleep_millisecs);
 277         write_num("khugepaged/scan_sleep_millisecs",
 278                         khugepaged->scan_sleep_millisecs);
 279         write_num("khugepaged/max_ptes_none", khugepaged->max_ptes_none);
 280         write_num("khugepaged/max_ptes_swap", khugepaged->max_ptes_swap);
 281         write_num("khugepaged/max_ptes_shared", khugepaged->max_ptes_shared);
 282         write_num("khugepaged/pages_to_scan", khugepaged->pages_to_scan);
 283 }
 284
 285 static void restore_settings(int sig)
 286 {
 287         if (skip_settings_restore)
 288                 goto out;
 289
 290         printf("Restore THP and khugepaged settings...");
 291         write_settings(&saved_settings);
 292         success("OK");
 293         if (sig)
 294                 exit(EXIT_FAILURE);
 295 out:
 296         exit(exit_status);
 297 }
 298
 299 static void save_settings(void)
 300 {
 301         printf("Save THP and khugepaged settings...");
 302         saved_settings = (struct settings) {
 303                 .thp_enabled = read_string("enabled", thp_enabled_strings),
 304                 .thp_defrag = read_string("defrag", thp_defrag_strings),
 305                 .shmem_enabled =
 306                         read_string("shmem_enabled", shmem_enabled_strings),
 307                 .debug_cow = read_num("debug_cow"),
 308                 .use_zero_page = read_num("use_zero_page"),
 309         };
 310         saved_settings.khugepaged = (struct khugepaged_settings) {
 311                 .defrag = read_num("khugepaged/defrag"),
 312                 .alloc_sleep_millisecs =
 313                         read_num("khugepaged/alloc_sleep_millisecs"),
 314                 .scan_sleep_millisecs =
 315                         read_num("khugepaged/scan_sleep_millisecs"),
 316                 .max_ptes_none = read_num("khugepaged/max_ptes_none"),
 317                 .max_ptes_swap = read_num("khugepaged/max_ptes_swap"),
 318                 .max_ptes_shared = read_num("khugepaged/max_ptes_shared"),
 319                 .pages_to_scan = read_num("khugepaged/pages_to_scan"),
 320         };
 321         success("OK");
 322
 323         signal(SIGTERM, restore_settings);
 324         signal(SIGINT, restore_settings);
 325         signal(SIGHUP, restore_settings);
 326         signal(SIGQUIT, restore_settings);
 327 }
 328
 329 static void adjust_settings(void)
 330 {
 331
 332         printf("Adjust settings...");
 333         write_settings(&default_settings);
 334         success("OK");
 335 }
 336
 337 #define MAX_LINE_LENGTH 500
 338
 339 static bool check_for_pattern(FILE *fp, char *pattern, char *buf)
 340 {
 341         while (fgets(buf, MAX_LINE_LENGTH, fp) != NULL) {
 342                 if (!strncmp(buf, pattern, strlen(pattern)))
 343                         return true;
 344         }
 345         return false;
 346 }
 347
 348 static bool check_huge(void *addr)
 349 {
 350         bool thp = false;
 351         int ret;
 352         FILE *fp;
 353         char buffer[MAX_LINE_LENGTH];
 354         char addr_pattern[MAX_LINE_LENGTH];
 355
 356         ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
 357                        (unsigned long) addr);
 358         if (ret >= MAX_LINE_LENGTH) {
 359                 printf("%s: Pattern is too long\n", __func__);
 360                 exit(EXIT_FAILURE);
 361         }
 362
 363
 364         fp = fopen(PID_SMAPS, "r");
 365         if (!fp) {
 366                 printf("%s: Failed to open file %s\n", __func__, PID_SMAPS);
 367                 exit(EXIT_FAILURE);
 368         }
 369         if (!check_for_pattern(fp, addr_pattern, buffer))
 370                 goto err_out;
 371
 372         ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "AnonHugePages:%10ld kB",
 373                        hpage_pmd_size >> 10);
 374         if (ret >= MAX_LINE_LENGTH) {
 375                 printf("%s: Pattern is too long\n", __func__);
 376                 exit(EXIT_FAILURE);
 377         }
 378         /*
 379          * Fetch the AnonHugePages: in the same block and check whether it got
 380          * the expected number of hugeepages next.
 381          */
 382         if (!check_for_pattern(fp, "AnonHugePages:", buffer))
 383                 goto err_out;
 384
 385         if (strncmp(buffer, addr_pattern, strlen(addr_pattern)))
 386                 goto err_out;
 387
 388         thp = true;
 389 err_out:
 390         fclose(fp);
 391         return thp;
 392 }
 393
 394
 395 static bool check_swap(void *addr, unsigned long size)
 396 {
 397         bool swap = false;
 398         int ret;
 399         FILE *fp;
 400         char buffer[MAX_LINE_LENGTH];
 401         char addr_pattern[MAX_LINE_LENGTH];
 402
 403         ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
 404                        (unsigned long) addr);
 405         if (ret >= MAX_LINE_LENGTH) {
 406                 printf("%s: Pattern is too long\n", __func__);
 407                 exit(EXIT_FAILURE);
 408         }
 409
 410
 411         fp = fopen(PID_SMAPS, "r");
 412         if (!fp) {
 413                 printf("%s: Failed to open file %s\n", __func__, PID_SMAPS);
 414                 exit(EXIT_FAILURE);
 415         }
 416         if (!check_for_pattern(fp, addr_pattern, buffer))
 417                 goto err_out;
 418
 419         ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "Swap:%19ld kB",
 420                        size >> 10);
 421         if (ret >= MAX_LINE_LENGTH) {
 422                 printf("%s: Pattern is too long\n", __func__);
 423                 exit(EXIT_FAILURE);
 424         }
 425         /*
 426          * Fetch the Swap: in the same block and check whether it got
 427          * the expected number of hugeepages next.
 428          */
 429         if (!check_for_pattern(fp, "Swap:", buffer))
 430                 goto err_out;
 431
 432         if (strncmp(buffer, addr_pattern, strlen(addr_pattern)))
 433                 goto err_out;
 434
 435         swap = true;
 436 err_out:
 437         fclose(fp);
 438         return swap;
 439 }
 440
 441 static void *alloc_mapping(void)
 442 {
 443         void *p;
 444
 445         p = mmap(BASE_ADDR, hpage_pmd_size, PROT_READ | PROT_WRITE,
 446                         MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
 447         if (p != BASE_ADDR) {
 448                 printf("Failed to allocate VMA at %p\n", BASE_ADDR);
 449                 exit(EXIT_FAILURE);
 450         }
 451
 452         return p;
 453 }
 454
 455 static void fill_memory(int *p, unsigned long start, unsigned long end)
 456 {
 457         int i;
 458
 459         for (i = start / page_size; i < end / page_size; i++)
 460                 p[i * page_size / sizeof(*p)] = i + 0xdead0000;
 461 }
 462
 463 static void validate_memory(int *p, unsigned long start, unsigned long end)
 464 {
 465         int i;
 466
 467         for (i = start / page_size; i < end / page_size; i++) {
 468                 if (p[i * page_size / sizeof(*p)] != i + 0xdead0000) {
 469                         printf("Page %d is corrupted: %#x\n",
 470                                         i, p[i * page_size / sizeof(*p)]);
 471                         exit(EXIT_FAILURE);
 472                 }
 473         }
 474 }
 475
 476 #define TICK 500000
 477 static bool wait_for_scan(const char *msg, char *p)
 478 {
 479         int full_scans;
 480         int timeout = 6; /* 3 seconds */
 481
 482         /* Sanity check */
 483         if (check_huge(p)) {
 484                 printf("Unexpected huge page\n");
 485                 exit(EXIT_FAILURE);
 486         }
 487
 488         madvise(p, hpage_pmd_size, MADV_HUGEPAGE);
 489
 490         /* Wait until the second full_scan completed */
 491         full_scans = read_num("khugepaged/full_scans") + 2;
 492
 493         printf("%s...", msg);
 494         while (timeout--) {
 495                 if (check_huge(p))
 496                         break;
 497                 if (read_num("khugepaged/full_scans") >= full_scans)
 498                         break;
 499                 printf(".");
 500                 usleep(TICK);
 501         }
 502
 503         madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);
 504
 505         return timeout == -1;
 506 }
 507
 508 static void alloc_at_fault(void)
 509 {
 510         struct settings settings = default_settings;
 511         char *p;
 512
 513         settings.thp_enabled = THP_ALWAYS;
 514         write_settings(&settings);
 515
 516         p = alloc_mapping();
 517         *p = 1;
 518         printf("Allocate huge page on fault...");
 519         if (check_huge(p))
 520                 success("OK");
 521         else
 522                 fail("Fail");
 523
 524         write_settings(&default_settings);
 525
 526         madvise(p, page_size, MADV_DONTNEED);
 527         printf("Split huge PMD on MADV_DONTNEED...");
 528         if (!check_huge(p))
 529                 success("OK");
 530         else
 531                 fail("Fail");
 532         munmap(p, hpage_pmd_size);
 533 }
 534
 535 static void collapse_full(void)
 536 {
 537         void *p;
 538
 539         p = alloc_mapping();
 540         fill_memory(p, 0, hpage_pmd_size);
 541         if (wait_for_scan("Collapse fully populated PTE table", p))
 542                 fail("Timeout");
 543         else if (check_huge(p))
 544                 success("OK");
 545         else
 546                 fail("Fail");
 547         validate_memory(p, 0, hpage_pmd_size);
 548         munmap(p, hpage_pmd_size);
 549 }
 550
 551 static void collapse_empty(void)
 552 {
 553         void *p;
 554
 555         p = alloc_mapping();
 556         if (wait_for_scan("Do not collapse empty PTE table", p))
 557                 fail("Timeout");
 558         else if (check_huge(p))
 559                 fail("Fail");
 560         else
 561                 success("OK");
 562         munmap(p, hpage_pmd_size);
 563 }
 564
 565 static void collapse_single_pte_entry(void)
 566 {
 567         void *p;
 568
 569         p = alloc_mapping();
 570         fill_memory(p, 0, page_size);
 571         if (wait_for_scan("Collapse PTE table with single PTE entry present", p))
 572                 fail("Timeout");
 573         else if (check_huge(p))
 574                 success("OK");
 575         else
 576                 fail("Fail");
 577         validate_memory(p, 0, page_size);
 578         munmap(p, hpage_pmd_size);
 579 }
 580
 581 static void collapse_max_ptes_none(void)
 582 {
 583         int max_ptes_none = hpage_pmd_nr / 2;
 584         struct settings settings = default_settings;
 585         void *p;
 586
 587         settings.khugepaged.max_ptes_none = max_ptes_none;
 588         write_settings(&settings);
 589
 590         p = alloc_mapping();
 591
 592         fill_memory(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size);
 593         if (wait_for_scan("Do not collapse with max_ptes_none exceeded", p))
 594                 fail("Timeout");
 595         else if (check_huge(p))
 596                 fail("Fail");
 597         else
 598                 success("OK");
 599         validate_memory(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size);
 600
 601         fill_memory(p, 0, (hpage_pmd_nr - max_ptes_none) * page_size);
 602         if (wait_for_scan("Collapse with max_ptes_none PTEs empty", p))
 603                 fail("Timeout");
 604         else if (check_huge(p))
 605                 success("OK");
 606         else
 607                 fail("Fail");
 608         validate_memory(p, 0, (hpage_pmd_nr - max_ptes_none) * page_size);
 609
 610         munmap(p, hpage_pmd_size);
 611         write_settings(&default_settings);
 612 }
 613
 614 static void collapse_swapin_single_pte(void)
 615 {
 616         void *p;
 617         p = alloc_mapping();
 618         fill_memory(p, 0, hpage_pmd_size);
 619
 620         printf("Swapout one page...");
 621         if (madvise(p, page_size, MADV_PAGEOUT)) {
 622                 perror("madvise(MADV_PAGEOUT)");
 623                 exit(EXIT_FAILURE);
 624         }
 625         if (check_swap(p, page_size)) {
 626                 success("OK");
 627         } else {
 628                 fail("Fail");
 629                 goto out;
 630         }
 631
 632         if (wait_for_scan("Collapse with swapping in single PTE entry", p))
 633                 fail("Timeout");
 634         else if (check_huge(p))
 635                 success("OK");
 636         else
 637                 fail("Fail");
 638         validate_memory(p, 0, hpage_pmd_size);
 639 out:
 640         munmap(p, hpage_pmd_size);
 641 }
 642
 643 static void collapse_max_ptes_swap(void)
 644 {
 645         int max_ptes_swap = read_num("khugepaged/max_ptes_swap");
 646         void *p;
 647
 648         p = alloc_mapping();
 649
 650         fill_memory(p, 0, hpage_pmd_size);
 651         printf("Swapout %d of %d pages...", max_ptes_swap + 1, hpage_pmd_nr);
 652         if (madvise(p, (max_ptes_swap + 1) * page_size, MADV_PAGEOUT)) {
 653                 perror("madvise(MADV_PAGEOUT)");
 654                 exit(EXIT_FAILURE);
 655         }
 656         if (check_swap(p, (max_ptes_swap + 1) * page_size)) {
 657                 success("OK");
 658         } else {
 659                 fail("Fail");
 660                 goto out;
 661         }
 662
 663         if (wait_for_scan("Do not collapse with max_ptes_swap exceeded", p))
 664                 fail("Timeout");
 665         else if (check_huge(p))
 666                 fail("Fail");
 667         else
 668                 success("OK");
 669         validate_memory(p, 0, hpage_pmd_size);
 670
 671         fill_memory(p, 0, hpage_pmd_size);
 672         printf("Swapout %d of %d pages...", max_ptes_swap, hpage_pmd_nr);
 673         if (madvise(p, max_ptes_swap * page_size, MADV_PAGEOUT)) {
 674                 perror("madvise(MADV_PAGEOUT)");
 675                 exit(EXIT_FAILURE);
 676         }
 677         if (check_swap(p, max_ptes_swap * page_size)) {
 678                 success("OK");
 679         } else {
 680                 fail("Fail");
 681                 goto out;
 682         }
 683
 684         if (wait_for_scan("Collapse with max_ptes_swap pages swapped out", p))
 685                 fail("Timeout");
 686         else if (check_huge(p))
 687                 success("OK");
 688         else
 689                 fail("Fail");
 690         validate_memory(p, 0, hpage_pmd_size);
 691 out:
 692         munmap(p, hpage_pmd_size);
 693 }
 694
 695 static void collapse_single_pte_entry_compound(void)
 696 {
 697         void *p;
 698
 699         p = alloc_mapping();
 700
 701         printf("Allocate huge page...");
 702         madvise(p, hpage_pmd_size, MADV_HUGEPAGE);
 703         fill_memory(p, 0, hpage_pmd_size);
 704         if (check_huge(p))
 705                 success("OK");
 706         else
 707                 fail("Fail");
 708         madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);
 709
 710         printf("Split huge page leaving single PTE mapping compound page...");
 711         madvise(p + page_size, hpage_pmd_size - page_size, MADV_DONTNEED);
 712         if (!check_huge(p))
 713                 success("OK");
 714         else
 715                 fail("Fail");
 716
 717         if (wait_for_scan("Collapse PTE table with single PTE mapping compound page", p))
 718                 fail("Timeout");
 719         else if (check_huge(p))
 720                 success("OK");
 721         else
 722                 fail("Fail");
 723         validate_memory(p, 0, page_size);
 724         munmap(p, hpage_pmd_size);
 725 }
 726
 727 static void collapse_full_of_compound(void)
 728 {
 729         void *p;
 730
 731         p = alloc_mapping();
 732
 733         printf("Allocate huge page...");
 734         madvise(p, hpage_pmd_size, MADV_HUGEPAGE);
 735         fill_memory(p, 0, hpage_pmd_size);
 736         if (check_huge(p))
 737                 success("OK");
 738         else
 739                 fail("Fail");
 740
 741         printf("Split huge page leaving single PTE page table full of compound pages...");
 742         madvise(p, page_size, MADV_NOHUGEPAGE);
 743         madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);
 744         if (!check_huge(p))
 745                 success("OK");
 746         else
 747                 fail("Fail");
 748
 749         if (wait_for_scan("Collapse PTE table full of compound pages", p))
 750                 fail("Timeout");
 751         else if (check_huge(p))
 752                 success("OK");
 753         else
 754                 fail("Fail");
 755         validate_memory(p, 0, hpage_pmd_size);
 756         munmap(p, hpage_pmd_size);
 757 }
 758
 759 static void collapse_compound_extreme(void)
 760 {
 761         void *p;
 762         int i;
 763
 764         p = alloc_mapping();
 765         for (i = 0; i < hpage_pmd_nr; i++) {
 766                 printf("\rConstruct PTE page table full of different PTE-mapped compound pages %3d/%d...",
 767                                 i + 1, hpage_pmd_nr);
 768
 769                 madvise(BASE_ADDR, hpage_pmd_size, MADV_HUGEPAGE);
 770                 fill_memory(BASE_ADDR, 0, hpage_pmd_size);
 771                 if (!check_huge(BASE_ADDR)) {
 772                         printf("Failed to allocate huge page\n");
 773                         exit(EXIT_FAILURE);
 774                 }
 775                 madvise(BASE_ADDR, hpage_pmd_size, MADV_NOHUGEPAGE);
 776
 777                 p = mremap(BASE_ADDR - i * page_size,
 778                                 i * page_size + hpage_pmd_size,
 779                                 (i + 1) * page_size,
 780                                 MREMAP_MAYMOVE | MREMAP_FIXED,
 781                                 BASE_ADDR + 2 * hpage_pmd_size);
 782                 if (p == MAP_FAILED) {
 783                         perror("mremap+unmap");
 784                         exit(EXIT_FAILURE);
 785                 }
 786
 787                 p = mremap(BASE_ADDR + 2 * hpage_pmd_size,
 788                                 (i + 1) * page_size,
 789                                 (i + 1) * page_size + hpage_pmd_size,
 790                                 MREMAP_MAYMOVE | MREMAP_FIXED,
 791                                 BASE_ADDR - (i + 1) * page_size);
 792                 if (p == MAP_FAILED) {
 793                         perror("mremap+alloc");
 794                         exit(EXIT_FAILURE);
 795                 }
 796         }
 797
 798         munmap(BASE_ADDR, hpage_pmd_size);
 799         fill_memory(p, 0, hpage_pmd_size);
 800         if (!check_huge(p))
 801                 success("OK");
 802         else
 803                 fail("Fail");
 804
 805         if (wait_for_scan("Collapse PTE table full of different compound pages", p))
 806                 fail("Timeout");
 807         else if (check_huge(p))
 808                 success("OK");
 809         else
 810                 fail("Fail");
 811
 812         validate_memory(p, 0, hpage_pmd_size);
 813         munmap(p, hpage_pmd_size);
 814 }
 815
 816 static void collapse_fork(void)
 817 {
 818         int wstatus;
 819         void *p;
 820
 821         p = alloc_mapping();
 822
 823         printf("Allocate small page...");
 824         fill_memory(p, 0, page_size);
 825         if (!check_huge(p))
 826                 success("OK");
 827         else
 828                 fail("Fail");
 829
 830         printf("Share small page over fork()...");
 831         if (!fork()) {
 832                 /* Do not touch settings on child exit */
 833                 skip_settings_restore = true;
 834                 exit_status = 0;
 835
 836                 if (!check_huge(p))
 837                         success("OK");
 838                 else
 839                         fail("Fail");
 840
 841                 fill_memory(p, page_size, 2 * page_size);
 842
 843                 if (wait_for_scan("Collapse PTE table with single page shared with parent process", p))
 844                         fail("Timeout");
 845                 else if (check_huge(p))
 846                         success("OK");
 847                 else
 848                         fail("Fail");
 849
 850                 validate_memory(p, 0, page_size);
 851                 munmap(p, hpage_pmd_size);
 852                 exit(exit_status);
 853         }
 854
 855         wait(&wstatus);
 856         exit_status += WEXITSTATUS(wstatus);
 857
 858         printf("Check if parent still has small page...");
 859         if (!check_huge(p))
 860                 success("OK");
 861         else
 862                 fail("Fail");
 863         validate_memory(p, 0, page_size);
 864         munmap(p, hpage_pmd_size);
 865 }
 866
 867 static void collapse_fork_compound(void)
 868 {
 869         int wstatus;
 870         void *p;
 871
 872         p = alloc_mapping();
 873
 874         printf("Allocate huge page...");
 875         madvise(p, hpage_pmd_size, MADV_HUGEPAGE);
 876         fill_memory(p, 0, hpage_pmd_size);
 877         if (check_huge(p))
 878                 success("OK");
 879         else
 880                 fail("Fail");
 881
 882         printf("Share huge page over fork()...");
 883         if (!fork()) {
 884                 /* Do not touch settings on child exit */
 885                 skip_settings_restore = true;
 886                 exit_status = 0;
 887
 888                 if (check_huge(p))
 889                         success("OK");
 890                 else
 891                         fail("Fail");
 892
 893                 printf("Split huge page PMD in child process...");
 894                 madvise(p, page_size, MADV_NOHUGEPAGE);
 895                 madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);
 896                 if (!check_huge(p))
 897                         success("OK");
 898                 else
 899                         fail("Fail");
 900                 fill_memory(p, 0, page_size);
 901
 902                 write_num("khugepaged/max_ptes_shared", hpage_pmd_nr - 1);
 903                 if (wait_for_scan("Collapse PTE table full of compound pages in child", p))
 904                         fail("Timeout");
 905                 else if (check_huge(p))
 906                         success("OK");
 907                 else
 908                         fail("Fail");
 909                 write_num("khugepaged/max_ptes_shared",
 910                                 default_settings.khugepaged.max_ptes_shared);
 911
 912                 validate_memory(p, 0, hpage_pmd_size);
 913                 munmap(p, hpage_pmd_size);
 914                 exit(exit_status);
 915         }
 916
 917         wait(&wstatus);
 918         exit_status += WEXITSTATUS(wstatus);
 919
 920         printf("Check if parent still has huge page...");
 921         if (check_huge(p))
 922                 success("OK");
 923         else
 924                 fail("Fail");
 925         validate_memory(p, 0, hpage_pmd_size);
 926         munmap(p, hpage_pmd_size);
 927 }
 928
 929 static void collapse_max_ptes_shared()
 930 {
 931         int max_ptes_shared = read_num("khugepaged/max_ptes_shared");
 932         int wstatus;
 933         void *p;
 934
 935         p = alloc_mapping();
 936
 937         printf("Allocate huge page...");
 938         madvise(p, hpage_pmd_size, MADV_HUGEPAGE);
 939         fill_memory(p, 0, hpage_pmd_size);
 940         if (check_huge(p))
 941                 success("OK");
 942         else
 943                 fail("Fail");
 944
 945         printf("Share huge page over fork()...");
 946         if (!fork()) {
 947                 /* Do not touch settings on child exit */
 948                 skip_settings_restore = true;
 949                 exit_status = 0;
 950
 951                 if (check_huge(p))
 952                         success("OK");
 953                 else
 954                         fail("Fail");
 955
 956                 printf("Trigger CoW on page %d of %d...",
 957                                 hpage_pmd_nr - max_ptes_shared - 1, hpage_pmd_nr);
 958                 fill_memory(p, 0, (hpage_pmd_nr - max_ptes_shared - 1) * page_size);
 959                 if (!check_huge(p))
 960                         success("OK");
 961                 else
 962                         fail("Fail");
 963
 964                 if (wait_for_scan("Do not collapse with max_ptes_shared exceeded", p))
 965                         fail("Timeout");
 966                 else if (!check_huge(p))
 967                         success("OK");
 968                 else
 969                         fail("Fail");
 970
 971                 printf("Trigger CoW on page %d of %d...",
 972                                 hpage_pmd_nr - max_ptes_shared, hpage_pmd_nr);
 973                 fill_memory(p, 0, (hpage_pmd_nr - max_ptes_shared) * page_size);
 974                 if (!check_huge(p))
 975                         success("OK");
 976                 else
 977                         fail("Fail");
 978
 979
 980                 if (wait_for_scan("Collapse with max_ptes_shared PTEs shared", p))
 981                         fail("Timeout");
 982                 else if (check_huge(p))
 983                         success("OK");
 984                 else
 985                         fail("Fail");
 986
 987                 validate_memory(p, 0, hpage_pmd_size);
 988                 munmap(p, hpage_pmd_size);
 989                 exit(exit_status);
 990         }
 991
 992         wait(&wstatus);
 993         exit_status += WEXITSTATUS(wstatus);
 994
 995         printf("Check if parent still has huge page...");
 996         if (check_huge(p))
 997                 success("OK");
 998         else
 999                 fail("Fail");
1000         validate_memory(p, 0, hpage_pmd_size);
1001         munmap(p, hpage_pmd_size);
1002 }
1003
1004 int main(void)
1005 {
1006         setbuf(stdout, NULL);
1007
1008         page_size = getpagesize();
1009         hpage_pmd_size = read_num("hpage_pmd_size");
1010         hpage_pmd_nr = hpage_pmd_size / page_size;
1011
1012         default_settings.khugepaged.max_ptes_none = hpage_pmd_nr - 1;
1013         default_settings.khugepaged.max_ptes_swap = hpage_pmd_nr / 8;
1014         default_settings.khugepaged.max_ptes_shared = hpage_pmd_nr / 2;
1015         default_settings.khugepaged.pages_to_scan = hpage_pmd_nr * 8;
1016
1017         save_settings();
1018         adjust_settings();
1019
1020         alloc_at_fault();
1021         collapse_full();
1022         collapse_empty();
1023         collapse_single_pte_entry();
1024         collapse_max_ptes_none();
1025         collapse_swapin_single_pte();
1026         collapse_max_ptes_swap();
1027         collapse_single_pte_entry_compound();
1028         collapse_full_of_compound();
1029         collapse_compound_extreme();
1030         collapse_fork();
1031         collapse_fork_compound();
1032         collapse_max_ptes_shared();
1033
1034         restore_settings(0);
1035 }