1 /*
2 * Copyright (C) 2010-2017 Red Hat, Inc.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
13 *
14 * Kernel Samepage Merging (KSM) for Memory Resource Controller
15 *
16 * Basic tests were to start several programs with same and different
17 * memory contents and ensure only to merge the ones with the same
18 * contents. When changed the content of one of merged pages in a
19 * process and to the mode "unmerging", it should discard all merged
20 * pages there. Also tested it is possible to disable KSM. There are
21 * also command-line options to specify the memory allocation size, and
22 * number of processes have same memory contents so it is possible to
23 * test more advanced things like KSM + OOM etc.
24 *
25 * Prerequisites:
26 *
27 * 1) ksm and ksmtuned daemons need to be disabled. Otherwise, it could
28 * distrub the testing as they also change some ksm tunables depends
29 * on current workloads.
30 *
31 * The test steps are:
32 * - Check ksm feature and backup current run setting.
33 * - Change run setting to 1 - merging.
34 * - 3 memory allocation programs have the memory contents that 2 of
35 * them are all 'a' and one is all 'b'.
36 * - Check ksm statistics and verify the content.
37 * - 1 program changes the memory content from all 'a' to all 'b'.
38 * - Check ksm statistics and verify the content.
39 * - All programs change the memory content to all 'd'.
40 * - Check ksm statistics and verify the content.
41 * - Change one page of a process.
42 * - Check ksm statistics and verify the content.
43 * - Change run setting to 2 - unmerging.
44 * - Check ksm statistics and verify the content.
45 * - Change run setting to 0 - stop.
46 */
47
48 #include <sys/types.h>
49 #include <sys/mman.h>
50 #include <sys/stat.h>
51 #include <sys/wait.h>
52 #include <errno.h>
53 #include <fcntl.h>
54 #include <signal.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <unistd.h>
59 #include "mem.h"
60 #include "ksm_common.h"
61
verify_ksm(void)62 static void verify_ksm(void)
63 {
64 write_memcg();
65 create_same_memory(size, num, unit);
66 }
67
setup(void)68 static void setup(void)
69 {
70 if (access(PATH_KSM, F_OK) == -1)
71 tst_brk(TCONF, "KSM configuration is not enabled");
72
73 if (access(PATH_KSM "merge_across_nodes", F_OK) == 0) {
74 SAFE_FILE_SCANF(PATH_KSM "merge_across_nodes",
75 "%d", &merge_across_nodes);
76 SAFE_FILE_PRINTF(PATH_KSM "merge_across_nodes", "1");
77 }
78
79 save_max_page_sharing();
80 parse_ksm_options(opt_sizestr, &size, opt_numstr, &num, opt_unitstr, &unit);
81 mount_mem("memcg", "cgroup", "memory", MEMCG_PATH, MEMCG_PATH_NEW);
82 }
83
cleanup(void)84 static void cleanup(void)
85 {
86 if (access(PATH_KSM "merge_across_nodes", F_OK) == 0)
87 FILE_PRINTF(PATH_KSM "merge_across_nodes",
88 "%d", merge_across_nodes);
89
90 restore_max_page_sharing();
91
92 umount_mem(MEMCG_PATH, MEMCG_PATH_NEW);
93 }
94
95 static struct tst_test test = {
96 .needs_root = 1,
97 .forks_child = 1,
98 .options = ksm_options,
99 .setup = setup,
100 .cleanup = cleanup,
101 .test_all = verify_ksm,
102 .min_kver = "2.6.32",
103 };
104