root/tools/testing/selftests/vm/transhuge-stress.c

DEFINITIONS

1. allocate_transhuge
2. main

   1 /*
   2  * Stress test for transparent huge pages, memory compaction and migration.
   3  *
   4  * Authors: Konstantin Khlebnikov <koct9i@gmail.com>
   5  *
   6  * This is free and unencumbered software released into the public domain.
   7  */
   8 
   9 #include <stdlib.h>
  10 #include <stdio.h>
  11 #include <stdint.h>
  12 #include <err.h>
  13 #include <time.h>
  14 #include <unistd.h>
  15 #include <fcntl.h>
  16 #include <string.h>
  17 #include <sys/mman.h>
  18 
  19 #define PAGE_SHIFT 12
  20 #define HPAGE_SHIFT 21
  21 
  22 #define PAGE_SIZE (1 << PAGE_SHIFT)
  23 #define HPAGE_SIZE (1 << HPAGE_SHIFT)
  24 
  25 #define PAGEMAP_PRESENT(ent)    (((ent) & (1ull << 63)) != 0)
  26 #define PAGEMAP_PFN(ent)        ((ent) & ((1ull << 55) - 1))
  27 
  28 int pagemap_fd;
  29 
  30 int64_t allocate_transhuge(void *ptr)
  31 {
  32         uint64_t ent[2];
  33 
  34         /* drop pmd */
  35         if (mmap(ptr, HPAGE_SIZE, PROT_READ | PROT_WRITE,
  36                                 MAP_FIXED | MAP_ANONYMOUS |
  37                                 MAP_NORESERVE | MAP_PRIVATE, -1, 0) != ptr)
  38                 errx(2, "mmap transhuge");
  39 
  40         if (madvise(ptr, HPAGE_SIZE, MADV_HUGEPAGE))
  41                 err(2, "MADV_HUGEPAGE");
  42 
  43         /* allocate transparent huge page */
  44         *(volatile void **)ptr = ptr;
  45 
  46         if (pread(pagemap_fd, ent, sizeof(ent),
  47                         (uintptr_t)ptr >> (PAGE_SHIFT - 3)) != sizeof(ent))
  48                 err(2, "read pagemap");
  49 
  50         if (PAGEMAP_PRESENT(ent[0]) && PAGEMAP_PRESENT(ent[1]) &&
  51             PAGEMAP_PFN(ent[0]) + 1 == PAGEMAP_PFN(ent[1]) &&
  52             !(PAGEMAP_PFN(ent[0]) & ((1 << (HPAGE_SHIFT - PAGE_SHIFT)) - 1)))
  53                 return PAGEMAP_PFN(ent[0]);
  54 
  55         return -1;
  56 }
  57 
  58 int main(int argc, char **argv)
  59 {
  60         size_t ram, len;
  61         void *ptr, *p;
  62         struct timespec a, b;
  63         double s;
  64         uint8_t *map;
  65         size_t map_len;
  66 
  67         ram = sysconf(_SC_PHYS_PAGES);
  68         if (ram > SIZE_MAX / sysconf(_SC_PAGESIZE) / 4)
  69                 ram = SIZE_MAX / 4;
  70         else
  71                 ram *= sysconf(_SC_PAGESIZE);
  72 
  73         if (argc == 1)
  74                 len = ram;
  75         else if (!strcmp(argv[1], "-h"))
  76                 errx(1, "usage: %s [size in MiB]", argv[0]);
  77         else
  78                 len = atoll(argv[1]) << 20;
  79 
  80         warnx("allocate %zd transhuge pages, using %zd MiB virtual memory"
  81               " and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20,
  82               len >> (20 + HPAGE_SHIFT - PAGE_SHIFT - 1));
  83 
  84         pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
  85         if (pagemap_fd < 0)
  86                 err(2, "open pagemap");
  87 
  88         len -= len % HPAGE_SIZE;
  89         ptr = mmap(NULL, len + HPAGE_SIZE, PROT_READ | PROT_WRITE,
  90                         MAP_ANONYMOUS | MAP_NORESERVE | MAP_PRIVATE, -1, 0);
  91         if (ptr == MAP_FAILED)
  92                 err(2, "initial mmap");
  93         ptr += HPAGE_SIZE - (uintptr_t)ptr % HPAGE_SIZE;
  94 
  95         if (madvise(ptr, len, MADV_HUGEPAGE))
  96                 err(2, "MADV_HUGEPAGE");
  97 
  98         map_len = ram >> (HPAGE_SHIFT - 1);
  99         map = malloc(map_len);
 100         if (!map)
 101                 errx(2, "map malloc");
 102 
 103         while (1) {
 104                 int nr_succeed = 0, nr_failed = 0, nr_pages = 0;
 105 
 106                 memset(map, 0, map_len);
 107 
 108                 clock_gettime(CLOCK_MONOTONIC, &a);
 109                 for (p = ptr; p < ptr + len; p += HPAGE_SIZE) {
 110                         int64_t pfn;
 111 
 112                         pfn = allocate_transhuge(p);
 113 
 114                         if (pfn < 0) {
 115                                 nr_failed++;
 116                         } else {
 117                                 size_t idx = pfn >> (HPAGE_SHIFT - PAGE_SHIFT);
 118 
 119                                 nr_succeed++;
 120                                 if (idx >= map_len) {
 121                                         map = realloc(map, idx + 1);
 122                                         if (!map)
 123                                                 errx(2, "map realloc");
 124                                         memset(map + map_len, 0, idx + 1 - map_len);
 125                                         map_len = idx + 1;
 126                                 }
 127                                 if (!map[idx])
 128                                         nr_pages++;
 129                                 map[idx] = 1;
 130                         }
 131 
 132                         /* split transhuge page, keep last page */
 133                         if (madvise(p, HPAGE_SIZE - PAGE_SIZE, MADV_DONTNEED))
 134                                 err(2, "MADV_DONTNEED");
 135                 }
 136                 clock_gettime(CLOCK_MONOTONIC, &b);
 137                 s = b.tv_sec - a.tv_sec + (b.tv_nsec - a.tv_nsec) / 1000000000.;
 138 
 139                 warnx("%.3f s/loop, %.3f ms/page, %10.3f MiB/s\t"
 140                       "%4d succeed, %4d failed, %4d different pages",
 141                       s, s * 1000 / (len >> HPAGE_SHIFT), len / s / (1 << 20),
 142                       nr_succeed, nr_failed, nr_pages);
 143         }
 144 }