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 <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 62 static void verify_ksm(void) 63 { 64 create_same_memory(size, num, unit); 65 } 66 67 static void setup(void) 68 { 69 if (access(PATH_KSM, F_OK) == -1) 70 tst_brk(TCONF, "KSM configuration is not enabled"); 71 72 save_max_page_sharing(); 73 74 parse_ksm_options(opt_sizestr, &size, opt_numstr, &num, opt_unitstr, &unit); 75 76 /* 77 * kernel commit 90bd6fd introduced a new KSM sysfs knob 78 * /sys/kernel/mm/ksm/merge_across_nodes, setting it to '0' 79 * will prevent KSM pages being merged across numa nodes, 80 * which will cause the case fail, so we need to make sure 81 * it is enabled before testing. 82 */ 83 if (access(PATH_KSM "merge_across_nodes", F_OK) == 0) { 84 SAFE_FILE_SCANF(PATH_KSM "merge_across_nodes", 85 "%d", &merge_across_nodes); 86 SAFE_FILE_PRINTF(PATH_KSM "merge_across_nodes", "1"); 87 } 88 } 89 90 static void cleanup(void) 91 { 92 if (access(PATH_KSM "merge_across_nodes", F_OK) == 0) 93 FILE_PRINTF(PATH_KSM "merge_across_nodes", 94 "%d", merge_across_nodes); 95 96 restore_max_page_sharing(); 97 } 98 99 static struct tst_test test = { 100 .needs_root = 1, 101 .forks_child = 1, 102 .options = ksm_options, 103 .setup = setup, 104 .cleanup = cleanup, 105 .test_all = verify_ksm, 106 .min_kver = "2.6.32", 107 }; 108
