// SPDX-License-Identifier: GPL-2.0
/*
* Test soft offline behavior for HugeTLB pages:
* - if enable_soft_offline = 0, hugepages should stay intact and soft
* offlining failed with EOPNOTSUPP.
* - if enable_soft_offline = 1, a hugepage should be dissolved and
* nr_hugepages/free_hugepages should be reduced by 1.
*
* Before running, make sure more than 2 hugepages of default_hugepagesz
* are allocated. For example, if /proc/meminfo/Hugepagesize is 2048kB:
* echo 8 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
*/
#define _GNU_SOURCE
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <linux/magic.h>
#include <linux/memfd.h>
#include <sys/mman.h>
#include <sys/statfs.h>
#include <sys/types.h>
#include "../kselftest.h"
#ifndef MADV_SOFT_OFFLINE
#define MADV_SOFT_OFFLINE 101
#endif
#define EPREFIX " !!! "
static int do_soft_offline(int fd, size_t len, int expect_errno)
{
char *filemap = NULL;
char *hwp_addr = NULL;
const unsigned long pagesize = getpagesize();
int ret = 0;
if (ftruncate(fd, len) < 0) {
ksft_perror(EPREFIX "ftruncate to len failed");
return -1;
}
filemap = mmap(NULL, len, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_POPULATE, fd, 0);
if (filemap == MAP_FAILED) {
ksft_perror(EPREFIX "mmap failed");
ret = -1;
goto untruncate;
}
memset(filemap, 0xab, len);
ksft_print_msg("Allocated %#lx bytes of hugetlb pages\n", len);
hwp_addr = filemap + len / 2;
ret = madvise(hwp_addr, pagesize, MADV_SOFT_OFFLINE);
ksft_print_msg("MADV_SOFT_OFFLINE %p ret=%d, errno=%d\n",
hwp_addr, ret, errno);
if (ret != 0)
ksft_perror(EPREFIX "madvise failed");
if (errno == expect_errno)
ret = 0;
else {
ksft_print_msg("MADV_SOFT_OFFLINE should ret %d\n",
expect_errno);
ret = -1;
}
munmap(filemap, len);
untruncate:
if (ftruncate(fd, 0) < 0)
ksft_perror(EPREFIX "ftruncate back to 0 failed");
return ret;
}
static int set_enable_soft_offline(int value)
{
char cmd[256] = {0};
FILE *cmdfile = NULL;
if (value != 0 && value != 1)
return -EINVAL;
sprintf(cmd, "echo %d > /proc/sys/vm/enable_soft_offline", value);
cmdfile = popen(cmd, "r");
if (cmdfile)
ksft_print_msg("enable_soft_offline => %d\n", value);
else {
ksft_perror(EPREFIX "failed to set enable_soft_offline");
return errno;
}
pclose(cmdfile);
return 0;
}
static int read_nr_hugepages(unsigned long hugepage_size,
unsigned long *nr_hugepages)
{
char buffer[256] = {0};
char cmd[256] = {0};
sprintf(cmd, "cat /sys/kernel/mm/hugepages/hugepages-%ldkB/nr_hugepages",
hugepage_size);
FILE *cmdfile = popen(cmd, "r");
if (cmdfile == NULL) {
ksft_perror(EPREFIX "failed to popen nr_hugepages");
return -1;
}
if (!fgets(buffer, sizeof(buffer), cmdfile)) {
ksft_perror(EPREFIX "failed to read nr_hugepages");
pclose(cmdfile);
return -1;
}
*nr_hugepages = atoll(buffer);
pclose(cmdfile);
return 0;
}
static int create_hugetlbfs_file(struct statfs *file_stat)
{
int fd;
fd = memfd_create("hugetlb_tmp", MFD_HUGETLB);
if (fd < 0) {
ksft_perror(EPREFIX "could not open hugetlbfs file");
return -1;
}
memset(file_stat, 0, sizeof(*file_stat));
if (fstatfs(fd, file_stat)) {
ksft_perror(EPREFIX "fstatfs failed");
goto close;
}
if (file_stat->f_type != HUGETLBFS_MAGIC) {
ksft_print_msg(EPREFIX "not hugetlbfs file\n");
goto close;
}
return fd;
close:
close(fd);
return -1;
}
static void test_soft_offline_common(int enable_soft_offline)
{
int fd;
int expect_errno = enable_soft_offline ? 0 : EOPNOTSUPP;
struct statfs file_stat;
unsigned long hugepagesize_kb = 0;
unsigned long nr_hugepages_before = 0;
unsigned long nr_hugepages_after = 0;
int ret;
ksft_print_msg("Test soft-offline when enabled_soft_offline=%d\n",
enable_soft_offline);
fd = create_hugetlbfs_file(&file_stat);
if (fd < 0)
ksft_exit_fail_msg("Failed to create hugetlbfs file\n");
hugepagesize_kb = file_stat.f_bsize / 1024;
ksft_print_msg("Hugepagesize is %ldkB\n", hugepagesize_kb);
if (set_enable_soft_offline(enable_soft_offline) != 0) {
close(fd);
ksft_exit_fail_msg("Failed to set enable_soft_offline\n");
}
if (read_nr_hugepages(hugepagesize_kb, &nr_hugepages_before) != 0) {
close(fd);
ksft_exit_fail_msg("Failed to read nr_hugepages\n");
}
ksft_print_msg("Before MADV_SOFT_OFFLINE nr_hugepages=%ld\n",
nr_hugepages_before);
ret = do_soft_offline(fd, 2 * file_stat.f_bsize, expect_errno);
if (read_nr_hugepages(hugepagesize_kb, &nr_hugepages_after) != 0) {
close(fd);
ksft_exit_fail_msg("Failed to read nr_hugepages\n");
}
ksft_print_msg("After MADV_SOFT_OFFLINE nr_hugepages=%ld\n",
nr_hugepages_after);
// No need for the hugetlbfs file from now on.
close(fd);
if (enable_soft_offline) {
if (nr_hugepages_before != nr_hugepages_after + 1) {
ksft_test_result_fail("MADV_SOFT_OFFLINE should reduced 1 hugepage\n");
return;
}
} else {
if (nr_hugepages_before != nr_hugepages_after) {
ksft_test_result_fail("MADV_SOFT_OFFLINE reduced %lu hugepages\n",
nr_hugepages_before - nr_hugepages_after);
return;
}
}
ksft_test_result(ret == 0,
"Test soft-offline when enabled_soft_offline=%d\n",
enable_soft_offline);
}
int main(int argc, char **argv)
{
ksft_print_header();
ksft_set_plan(2);
test_soft_offline_common(1);
test_soft_offline_common(0);
ksft_finished();
}
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