229 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Test soft offline behavior for HugeTLB pages:4 * - if enable_soft_offline = 0, hugepages should stay intact and soft5 * offlining failed with EOPNOTSUPP.6 * - if enable_soft_offline = 1, a hugepage should be dissolved and7 * nr_hugepages/free_hugepages should be reduced by 1.8 *9 * Before running, make sure more than 2 hugepages of default_hugepagesz10 * are allocated. For example, if /proc/meminfo/Hugepagesize is 2048kB:11 * echo 8 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages12 */13 14#define _GNU_SOURCE15#include <errno.h>16#include <stdlib.h>17#include <stdio.h>18#include <string.h>19#include <unistd.h>20 21#include <linux/magic.h>22#include <linux/memfd.h>23#include <sys/mman.h>24#include <sys/statfs.h>25#include <sys/types.h>26 27#include "../kselftest.h"28 29#ifndef MADV_SOFT_OFFLINE30#define MADV_SOFT_OFFLINE 10131#endif32 33#define EPREFIX " !!! "34 35static int do_soft_offline(int fd, size_t len, int expect_errno)36{37 char *filemap = NULL;38 char *hwp_addr = NULL;39 const unsigned long pagesize = getpagesize();40 int ret = 0;41 42 if (ftruncate(fd, len) < 0) {43 ksft_perror(EPREFIX "ftruncate to len failed");44 return -1;45 }46 47 filemap = mmap(NULL, len, PROT_READ | PROT_WRITE,48 MAP_SHARED | MAP_POPULATE, fd, 0);49 if (filemap == MAP_FAILED) {50 ksft_perror(EPREFIX "mmap failed");51 ret = -1;52 goto untruncate;53 }54 55 memset(filemap, 0xab, len);56 ksft_print_msg("Allocated %#lx bytes of hugetlb pages\n", len);57 58 hwp_addr = filemap + len / 2;59 ret = madvise(hwp_addr, pagesize, MADV_SOFT_OFFLINE);60 ksft_print_msg("MADV_SOFT_OFFLINE %p ret=%d, errno=%d\n",61 hwp_addr, ret, errno);62 if (ret != 0)63 ksft_perror(EPREFIX "madvise failed");64 65 if (errno == expect_errno)66 ret = 0;67 else {68 ksft_print_msg("MADV_SOFT_OFFLINE should ret %d\n",69 expect_errno);70 ret = -1;71 }72 73 munmap(filemap, len);74untruncate:75 if (ftruncate(fd, 0) < 0)76 ksft_perror(EPREFIX "ftruncate back to 0 failed");77 78 return ret;79}80 81static int set_enable_soft_offline(int value)82{83 char cmd[256] = {0};84 FILE *cmdfile = NULL;85 86 if (value != 0 && value != 1)87 return -EINVAL;88 89 sprintf(cmd, "echo %d > /proc/sys/vm/enable_soft_offline", value);90 cmdfile = popen(cmd, "r");91 92 if (cmdfile)93 ksft_print_msg("enable_soft_offline => %d\n", value);94 else {95 ksft_perror(EPREFIX "failed to set enable_soft_offline");96 return errno;97 }98 99 pclose(cmdfile);100 return 0;101}102 103static int read_nr_hugepages(unsigned long hugepage_size,104 unsigned long *nr_hugepages)105{106 char buffer[256] = {0};107 char cmd[256] = {0};108 109 sprintf(cmd, "cat /sys/kernel/mm/hugepages/hugepages-%ldkB/nr_hugepages",110 hugepage_size);111 FILE *cmdfile = popen(cmd, "r");112 113 if (cmdfile == NULL) {114 ksft_perror(EPREFIX "failed to popen nr_hugepages");115 return -1;116 }117 118 if (!fgets(buffer, sizeof(buffer), cmdfile)) {119 ksft_perror(EPREFIX "failed to read nr_hugepages");120 pclose(cmdfile);121 return -1;122 }123 124 *nr_hugepages = atoll(buffer);125 pclose(cmdfile);126 return 0;127}128 129static int create_hugetlbfs_file(struct statfs *file_stat)130{131 int fd;132 133 fd = memfd_create("hugetlb_tmp", MFD_HUGETLB);134 if (fd < 0) {135 ksft_perror(EPREFIX "could not open hugetlbfs file");136 return -1;137 }138 139 memset(file_stat, 0, sizeof(*file_stat));140 if (fstatfs(fd, file_stat)) {141 ksft_perror(EPREFIX "fstatfs failed");142 goto close;143 }144 if (file_stat->f_type != HUGETLBFS_MAGIC) {145 ksft_print_msg(EPREFIX "not hugetlbfs file\n");146 goto close;147 }148 149 return fd;150close:151 close(fd);152 return -1;153}154 155static void test_soft_offline_common(int enable_soft_offline)156{157 int fd;158 int expect_errno = enable_soft_offline ? 0 : EOPNOTSUPP;159 struct statfs file_stat;160 unsigned long hugepagesize_kb = 0;161 unsigned long nr_hugepages_before = 0;162 unsigned long nr_hugepages_after = 0;163 int ret;164 165 ksft_print_msg("Test soft-offline when enabled_soft_offline=%d\n",166 enable_soft_offline);167 168 fd = create_hugetlbfs_file(&file_stat);169 if (fd < 0)170 ksft_exit_fail_msg("Failed to create hugetlbfs file\n");171 172 hugepagesize_kb = file_stat.f_bsize / 1024;173 ksft_print_msg("Hugepagesize is %ldkB\n", hugepagesize_kb);174 175 if (set_enable_soft_offline(enable_soft_offline) != 0) {176 close(fd);177 ksft_exit_fail_msg("Failed to set enable_soft_offline\n");178 }179 180 if (read_nr_hugepages(hugepagesize_kb, &nr_hugepages_before) != 0) {181 close(fd);182 ksft_exit_fail_msg("Failed to read nr_hugepages\n");183 }184 185 ksft_print_msg("Before MADV_SOFT_OFFLINE nr_hugepages=%ld\n",186 nr_hugepages_before);187 188 ret = do_soft_offline(fd, 2 * file_stat.f_bsize, expect_errno);189 190 if (read_nr_hugepages(hugepagesize_kb, &nr_hugepages_after) != 0) {191 close(fd);192 ksft_exit_fail_msg("Failed to read nr_hugepages\n");193 }194 195 ksft_print_msg("After MADV_SOFT_OFFLINE nr_hugepages=%ld\n",196 nr_hugepages_after);197 198 // No need for the hugetlbfs file from now on.199 close(fd);200 201 if (enable_soft_offline) {202 if (nr_hugepages_before != nr_hugepages_after + 1) {203 ksft_test_result_fail("MADV_SOFT_OFFLINE should reduced 1 hugepage\n");204 return;205 }206 } else {207 if (nr_hugepages_before != nr_hugepages_after) {208 ksft_test_result_fail("MADV_SOFT_OFFLINE reduced %lu hugepages\n",209 nr_hugepages_before - nr_hugepages_after);210 return;211 }212 }213 214 ksft_test_result(ret == 0,215 "Test soft-offline when enabled_soft_offline=%d\n",216 enable_soft_offline);217}218 219int main(int argc, char **argv)220{221 ksft_print_header();222 ksft_set_plan(2);223 224 test_soft_offline_common(1);225 test_soft_offline_common(0);226 227 ksft_finished();228}229