LXR linux/tools/testing/selftests/vm/hugetlbfstest.c

   1#define _GNU_SOURCE
   2#include <assert.h>
   3#include <fcntl.h>
   4#include <stdio.h>
   5#include <stdlib.h>
   6#include <string.h>
   7#include <sys/mman.h>
   8#include <sys/stat.h>
   9#include <sys/types.h>
  10#include <unistd.h>
  11
  12typedef unsigned long long u64;
  13
  14static size_t length = 1 << 24;
  15
  16static u64 read_rss(void)
  17{
  18        char buf[4096], *s = buf;
  19        int i, fd;
  20        u64 rss;
  21
  22        fd = open("/proc/self/statm", O_RDONLY);
  23        assert(fd > 2);
  24        memset(buf, 0, sizeof(buf));
  25        read(fd, buf, sizeof(buf) - 1);
  26        for (i = 0; i < 1; i++)
  27                s = strchr(s, ' ') + 1;
  28        rss = strtoull(s, NULL, 10);
  29        return rss << 12; /* assumes 4k pagesize */
  30}
  31
  32static void do_mmap(int fd, int extra_flags, int unmap)
  33{
  34        int *p;
  35        int flags = MAP_PRIVATE | MAP_POPULATE | extra_flags;
  36        u64 before, after;
  37
  38        before = read_rss();
  39        p = mmap(NULL, length, PROT_READ | PROT_WRITE, flags, fd, 0);
  40        assert(p != MAP_FAILED ||
  41                        !"mmap returned an unexpected error");
  42        after = read_rss();
  43        assert(llabs(after - before - length) < 0x40000 ||
  44                        !"rss didn't grow as expected");
  45        if (!unmap)
  46                return;
  47        munmap(p, length);
  48        after = read_rss();
  49        assert(llabs(after - before) < 0x40000 ||
  50                        !"rss didn't shrink as expected");
  51}
  52
  53static int open_file(const char *path)
  54{
  55        int fd, err;
  56
  57        unlink(path);
  58        fd = open(path, O_CREAT | O_RDWR | O_TRUNC | O_EXCL
  59                        | O_LARGEFILE | O_CLOEXEC, 0600);
  60        assert(fd > 2);
  61        unlink(path);
  62        err = ftruncate(fd, length);
  63        assert(!err);
  64        return fd;
  65}
  66
  67int main(void)
  68{
  69        int hugefd, fd;
  70
  71        fd = open_file("/dev/shm/hugetlbhog");
  72        hugefd = open_file("/hugepages/hugetlbhog");
  73
  74        system("echo 100 > /proc/sys/vm/nr_hugepages");
  75        do_mmap(-1, MAP_ANONYMOUS, 1);
  76        do_mmap(fd, 0, 1);
  77        do_mmap(-1, MAP_ANONYMOUS | MAP_HUGETLB, 1);
  78        do_mmap(hugefd, 0, 1);
  79        do_mmap(hugefd, MAP_HUGETLB, 1);
  80        /* Leak the last one to test do_exit() */
  81        do_mmap(-1, MAP_ANONYMOUS | MAP_HUGETLB, 0);
  82        printf("oll korrekt.\n");
  83        return 0;
  84}
  85