1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * 4 * A test for the patch "Allow compaction of unevictable pages". 5 * With this patch we should be able to allocate at least 1/4 6 * of RAM in huge pages. Without the patch much less is 7 * allocated. 8 */ 9 10 #include <stdio.h> 11 #include <stdlib.h> 12 #include <sys/mman.h> 13 #include <sys/resource.h> 14 #include <fcntl.h> 15 #include <errno.h> 16 #include <unistd.h> 17 #include <string.h> 18 19 #include "../kselftest.h" 20 21 #define MAP_SIZE_MB 100 22 #define MAP_SIZE (MAP_SIZE_MB * 1024 * 1024) 23 24 struct map_list { 25 void *map; 26 struct map_list *next; 27 }; 28 29 int read_memory_info(unsigned long *memfree, unsigned long *hugepagesize) 30 { 31 char buffer[256] = {0}; 32 char *cmd = "cat /proc/meminfo | grep -i memfree | grep -o '[0-9]*'"; 33 FILE *cmdfile = popen(cmd, "r"); 34 35 if (!(fgets(buffer, sizeof(buffer), cmdfile))) { 36 ksft_print_msg("Failed to read meminfo: %s\n", strerror(errno)); 37 return -1; 38 } 39 40 pclose(cmdfile); 41 42 *memfree = atoll(buffer); 43 cmd = "cat /proc/meminfo | grep -i hugepagesize | grep -o '[0-9]*'"; 44 cmdfile = popen(cmd, "r"); 45 46 if (!(fgets(buffer, sizeof(buffer), cmdfile))) { 47 ksft_print_msg("Failed to read meminfo: %s\n", strerror(errno)); 48 return -1; 49 } 50 51 pclose(cmdfile); 52 *hugepagesize = atoll(buffer); 53 54 return 0; 55 } 56 57 int prereq(void) 58 { 59 char allowed; 60 int fd; 61 62 fd = open("/proc/sys/vm/compact_unevictable_allowed", 63 O_RDONLY | O_NONBLOCK); 64 if (fd < 0) { 65 ksft_print_msg("Failed to open /proc/sys/vm/compact_unevictable_allowed: %s\n", 66 strerror(errno)); 67 return -1; 68 } 69 70 if (read(fd, &allowed, sizeof(char)) != sizeof(char)) { 71 ksft_print_msg("Failed to read from /proc/sys/vm/compact_unevictable_allowed: %s\n", 72 strerror(errno)); 73 close(fd); 74 return -1; 75 } 76 77 close(fd); 78 if (allowed == '1') 79 return 0; 80 81 ksft_print_msg("Compaction isn't allowed\n"); 82 return -1; 83 } 84 85 int check_compaction(unsigned long mem_free, unsigned long hugepage_size) 86 { 87 unsigned long nr_hugepages_ul; 88 int fd, ret = -1; 89 int compaction_index = 0; 90 char initial_nr_hugepages[20] = {0}; 91 char nr_hugepages[20] = {0}; 92 93 /* We want to test with 80% of available memory. Else, OOM killer comes 94 in to play */ 95 mem_free = mem_free * 0.8; 96 97 fd = open("/proc/sys/vm/nr_hugepages", O_RDWR | O_NONBLOCK); 98 if (fd < 0) { 99 ksft_print_msg("Failed to open /proc/sys/vm/nr_hugepages: %s\n", 100 strerror(errno)); 101 ret = -1; 102 goto out; 103 } 104 105 if (read(fd, initial_nr_hugepages, sizeof(initial_nr_hugepages)) <= 0) { 106 ksft_print_msg("Failed to read from /proc/sys/vm/nr_hugepages: %s\n", 107 strerror(errno)); 108 goto close_fd; 109 } 110 111 lseek(fd, 0, SEEK_SET); 112 113 /* Start with the initial condition of 0 huge pages*/ 114 if (write(fd, "0", sizeof(char)) != sizeof(char)) { 115 ksft_print_msg("Failed to write 0 to /proc/sys/vm/nr_hugepages: %s\n", 116 strerror(errno)); 117 goto close_fd; 118 } 119 120 lseek(fd, 0, SEEK_SET); 121 122 /* Request a large number of huge pages. The Kernel will allocate 123 as much as it can */ 124 if (write(fd, "100000", (6*sizeof(char))) != (6*sizeof(char))) { 125 ksft_print_msg("Failed to write 100000 to /proc/sys/vm/nr_hugepages: %s\n", 126 strerror(errno)); 127 goto close_fd; 128 } 129 130 lseek(fd, 0, SEEK_SET); 131 132 if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) { 133 ksft_print_msg("Failed to re-read from /proc/sys/vm/nr_hugepages: %s\n", 134 strerror(errno)); 135 goto close_fd; 136 } 137 138 /* We should have been able to request at least 1/3 rd of the memory in 139 huge pages */ 140 nr_hugepages_ul = strtoul(nr_hugepages, NULL, 10); 141 if (!nr_hugepages_ul) { 142 ksft_print_msg("ERROR: No memory is available as huge pages\n"); 143 goto close_fd; 144 } 145 compaction_index = mem_free/(nr_hugepages_ul * hugepage_size); 146 147 lseek(fd, 0, SEEK_SET); 148 149 if (write(fd, initial_nr_hugepages, strlen(initial_nr_hugepages)) 150 != strlen(initial_nr_hugepages)) { 151 ksft_print_msg("Failed to write value to /proc/sys/vm/nr_hugepages: %s\n", 152 strerror(errno)); 153 goto close_fd; 154 } 155 156 ksft_print_msg("Number of huge pages allocated = %lu\n", 157 nr_hugepages_ul); 158 159 if (compaction_index > 3) { 160 ksft_print_msg("ERROR: Less than 1/%d of memory is available\n" 161 "as huge pages\n", compaction_index); 162 goto close_fd; 163 } 164 165 ret = 0; 166 167 close_fd: 168 close(fd); 169 out: 170 ksft_test_result(ret == 0, "check_compaction\n"); 171 return ret; 172 } 173 174 175 int main(int argc, char **argv) 176 { 177 struct rlimit lim; 178 struct map_list *list = NULL, *entry; 179 size_t page_size, i; 180 void *map = NULL; 181 unsigned long mem_free = 0; 182 unsigned long hugepage_size = 0; 183 long mem_fragmentable_MB = 0; 184 185 ksft_print_header(); 186 187 if (prereq() != 0) 188 return ksft_exit_pass(); 189 190 ksft_set_plan(1); 191 192 lim.rlim_cur = RLIM_INFINITY; 193 lim.rlim_max = RLIM_INFINITY; 194 if (setrlimit(RLIMIT_MEMLOCK, &lim)) 195 ksft_exit_fail_msg("Failed to set rlimit: %s\n", strerror(errno)); 196 197 page_size = getpagesize(); 198 199 if (read_memory_info(&mem_free, &hugepage_size) != 0) 200 ksft_exit_fail_msg("Failed to get meminfo\n"); 201 202 mem_fragmentable_MB = mem_free * 0.8 / 1024; 203 204 while (mem_fragmentable_MB > 0) { 205 map = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE, 206 MAP_ANONYMOUS | MAP_PRIVATE | MAP_LOCKED, -1, 0); 207 if (map == MAP_FAILED) 208 break; 209 210 entry = malloc(sizeof(struct map_list)); 211 if (!entry) { 212 munmap(map, MAP_SIZE); 213 break; 214 } 215 entry->map = map; 216 entry->next = list; 217 list = entry; 218 219 /* Write something (in this case the address of the map) to 220 * ensure that KSM can't merge the mapped pages 221 */ 222 for (i = 0; i < MAP_SIZE; i += page_size) 223 *(unsigned long *)(map + i) = (unsigned long)map + i; 224 225 mem_fragmentable_MB -= MAP_SIZE_MB; 226 } 227 228 for (entry = list; entry != NULL; entry = entry->next) { 229 munmap(entry->map, MAP_SIZE); 230 if (!entry->next) 231 break; 232 entry = entry->next; 233 } 234 235 if (check_compaction(mem_free, hugepage_size) == 0) 236 return ksft_exit_pass(); 237 238 return ksft_exit_fail(); 239 } 240