LXR linux/tools/testing/selftests/vm/transhuge-stress.c

   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
  28int pagemap_fd;
  29
  30int64_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
  58int 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}
 145