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}