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)
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 "config.h"
49 #include <sys/types.h>
50 #include <sys/stat.h>
51 #include <errno.h>
52 #include <fcntl.h>
53 #include <signal.h>
54 #include <stdio.h>
55 #include <unistd.h>
56 #include "mem.h"
57 #include "ksm_common.h"
58
59 #ifdef HAVE_NUMA_V2
60 #include <numaif.h>
61
62 static const struct tst_cgroup_group *cg;
63 static const struct tst_cgroup_group *cg_drain;
64
verify_ksm(void)65 static void verify_ksm(void)
66 {
67 unsigned long nmask[MAXNODES / BITS_PER_LONG] = { 0 };
68 unsigned int node;
69
70 node = get_a_numa_node();
71 set_node(nmask, node);
72
73 if (set_mempolicy(MPOL_BIND, nmask, MAXNODES) == -1) {
74 if (errno != ENOSYS)
75 tst_brk(TBROK | TERRNO, "set_mempolicy");
76 else
77 tst_brk(TCONF, "set_mempolicy syscall is not "
78 "implemented on your system.");
79 }
80 create_same_memory(size, num, unit);
81
82 write_cpusets(cg, node);
83 SAFE_CGROUP_PRINTF(cg, "cgroup.procs", "%d", getpid());
84 create_same_memory(size, num, unit);
85 SAFE_CGROUP_PRINTF(cg_drain, "cgroup.procs", "%d", getpid());
86 }
87
cleanup(void)88 static void cleanup(void)
89 {
90 if (access(PATH_KSM "merge_across_nodes", F_OK) == 0)
91 FILE_PRINTF(PATH_KSM "merge_across_nodes",
92 "%d", merge_across_nodes);
93
94 tst_cgroup_cleanup();
95 }
96
setup(void)97 static void setup(void)
98 {
99 if (access(PATH_KSM, F_OK) == -1)
100 tst_brk(TCONF, "KSM configuration is not enabled");
101
102 parse_ksm_options(opt_sizestr, &size, opt_numstr, &num, opt_unitstr, &unit);
103
104 if (access(PATH_KSM "merge_across_nodes", F_OK) == 0) {
105 SAFE_FILE_SCANF(PATH_KSM "merge_across_nodes",
106 "%d", &merge_across_nodes);
107 SAFE_FILE_PRINTF(PATH_KSM "merge_across_nodes", "1");
108 }
109
110 tst_cgroup_require("cpuset", NULL);
111 cg = tst_cgroup_get_test_group();
112 cg_drain = tst_cgroup_get_drain_group();
113 }
114
115 static struct tst_test test = {
116 .needs_root = 1,
117 .forks_child = 1,
118 .options = (struct tst_option[]) {
119 {"n:", &opt_numstr, "Number of processes"},
120 {"s:", &opt_sizestr, "Memory allocation size in MB"},
121 {"u:", &opt_unitstr, "Memory allocation unit in MB"},
122 {}
123 },
124 .setup = setup,
125 .cleanup = cleanup,
126 .save_restore = (const char * const[]) {
127 "?/sys/kernel/mm/ksm/max_page_sharing",
128 NULL,
129 },
130 .test_all = verify_ksm,
131 .min_kver = "2.6.32",
132 };
133
134 #else
135 TST_TEST_TCONF(NUMA_ERROR_MSG);
136 #endif
137