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	int ret;
38
39	before = read_rss();
40	p = mmap(NULL, length, PROT_READ | PROT_WRITE, flags, fd, 0);
41	assert(p != MAP_FAILED ||
42			!"mmap returned an unexpected error");
43	after = read_rss();
44	assert(llabs(after - before - length) < 0x40000 ||
45			!"rss didn't grow as expected");
46	if (!unmap)
47		return;
48	ret = munmap(p, length);
49	assert(!ret || !"munmap returned an unexpected error");
50	after = read_rss();
51	assert(llabs(after - before) < 0x40000 ||
52			!"rss didn't shrink as expected");
53}
54
55static int open_file(const char *path)
56{
57	int fd, err;
58
59	unlink(path);
60	fd = open(path, O_CREAT | O_RDWR | O_TRUNC | O_EXCL
61			| O_LARGEFILE | O_CLOEXEC, 0600);
62	assert(fd > 2);
63	unlink(path);
64	err = ftruncate(fd, length);
65	assert(!err);
66	return fd;
67}
68
69int main(void)
70{
71	int hugefd, fd;
72
73	fd = open_file("/dev/shm/hugetlbhog");
74	hugefd = open_file("/hugepages/hugetlbhog");
75
76	system("echo 100 > /proc/sys/vm/nr_hugepages");
77	do_mmap(-1, MAP_ANONYMOUS, 1);
78	do_mmap(fd, 0, 1);
79	do_mmap(-1, MAP_ANONYMOUS | MAP_HUGETLB, 1);
80	do_mmap(hugefd, 0, 1);
81	do_mmap(hugefd, MAP_HUGETLB, 1);
82	/* Leak the last one to test do_exit() */
83	do_mmap(-1, MAP_ANONYMOUS | MAP_HUGETLB, 0);
84	printf("oll korrekt.\n");
85	return 0;
86}
87