Re: [PATCH v2 2/3] selftest/mm: test enable_soft_offline behaviors

On 2024/6/12 5:55, Jiaqi Yan wrote:

Add regression and new tests when hugepage has correctable memory errors, and how userspace wants to deal with it:

• if enable_soft_offline=0, mapped hugepage is soft offlined
• if enable_soft_offline=1, mapped hugepage is intact

This shoule be something like below ? if enable_soft_offline=0, mapped hugepage is intact if enable_soft_offline=1, mapped hugepage is soft offlined

Free hugepages case is not explicitly covered by the tests.

Hugepage having corrected memory errors is emulated with MADV_SOFT_OFFLINE.

Signed-off-by: Jiaqi Yan jiaqiyan@google.com

tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 1 + .../selftests/mm/hugetlb-soft-offline.c | 258 ++++++++++++++++++ tools/testing/selftests/mm/run_vmtests.sh | 4 + 4 files changed, 264 insertions(+) create mode 100644 tools/testing/selftests/mm/hugetlb-soft-offline.c

diff --git a/tools/testing/selftests/mm/.gitignore b/tools/testing/selftests/mm/.gitignore index 0b9ab987601c..064e7b125643 100644 --- a/tools/testing/selftests/mm/.gitignore +++ b/tools/testing/selftests/mm/.gitignore @@ -6,6 +6,7 @@ hugepage-shm hugepage-vmemmap hugetlb-madvise hugetlb-read-hwpoison +hugetlb-soft-offline khugepaged map_hugetlb map_populate diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index 3b49bc3d0a3b..d166067d75ef 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -42,6 +42,7 @@ TEST_GEN_FILES += gup_test TEST_GEN_FILES += hmm-tests TEST_GEN_FILES += hugetlb-madvise TEST_GEN_FILES += hugetlb-read-hwpoison +TEST_GEN_FILES += hugetlb-soft-offline TEST_GEN_FILES += hugepage-mmap TEST_GEN_FILES += hugepage-mremap TEST_GEN_FILES += hugepage-shm diff --git a/tools/testing/selftests/mm/hugetlb-soft-offline.c b/tools/testing/selftests/mm/hugetlb-soft-offline.c new file mode 100644 index 000000000000..d37d68a433e7 --- /dev/null +++ b/tools/testing/selftests/mm/hugetlb-soft-offline.c @@ -0,0 +1,258 @@ +// 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 EINVAL.
• • • 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>

+#ifndef MADV_SOFT_OFFLINE +#define MADV_SOFT_OFFLINE 101 +#endif

+#define PREFIX " ... " +#define EPREFIX " !!! "

+enum test_status {

• TEST_PASS = 0,
• TEST_FAILED = 1,
• // From ${ksft_skip} in run_vmtests.sh.
• TEST_SKIPPED = 4,

+};

+static enum test_status do_soft_offline(int fd, size_t len, int expect_ret) +{

• char *filemap = NULL;
• char *hwp_addr = NULL;
• const unsigned long pagesize = getpagesize();
• int ret = 0;
• enum test_status status = TEST_SKIPPED;
• if (ftruncate(fd, len) < 0) {

• perror(EPREFIX "ftruncate to len failed");
  

• return status;
  

• }
• filemap = mmap(NULL, len, PROT_READ | PROT_WRITE,

•        MAP_SHARED | MAP_POPULATE, fd, 0);
  

• if (filemap == MAP_FAILED) {

• perror(EPREFIX "mmap failed");
  

• goto untruncate;
  

• }
• memset(filemap, 0xab, len);
• printf(PREFIX "Allocated %#lx bytes of hugetlb pages\n", len);
• hwp_addr = filemap + len / 2;
• ret = madvise(hwp_addr, pagesize, MADV_SOFT_OFFLINE);
• printf(PREFIX "MADV_SOFT_OFFLINE %p ret=%d, errno=%d\n",

•       hwp_addr, ret, errno);
  

• if (ret != 0)

• perror(EPREFIX "madvise failed");
  

• if (errno == expect_ret)

• status = TEST_PASS;
  

• else {

• printf(EPREFIX "MADV_SOFT_OFFLINE should ret %d\n", expect_ret);
  

• status = TEST_FAILED;
  

• }
• munmap(filemap, len);

+untruncate:

• if (ftruncate(fd, 0) < 0)

• perror(EPREFIX "ftruncate back to 0 failed");
  

• return status;

+}

+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 == NULL)

• perror(EPREFIX "failed to set enable_soft_offline");
  

If fails to set enable_soft_offline, should we return errno here?

• else

• printf(PREFIX "enable_soft_offline => %d\n", value);
  

• 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");

Check cmdfile against NULL?

• if (!fgets(buffer, sizeof(buffer), cmdfile)) {

• 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) {

• perror(EPREFIX "could not open hugetlbfs file");
  

• return -1;
  

• }
• memset(file_stat, 0, sizeof(*file_stat));
• if (fstatfs(fd, file_stat)) {

• perror(EPREFIX "fstatfs failed");
  

• goto close;
  

• }
• if (file_stat->f_type != HUGETLBFS_MAGIC) {

• printf(EPREFIX "not hugetlbfs file\n");
  

• goto close;
  

• }
• return fd;

+close:

• close(fd);
• return -1;

+}

+static enum test_status test_soft_offline(void) +{

• int fd;
• struct statfs file_stat;
• unsigned long hugepagesize_kb = 0;
• unsigned long nr_hugepages_before = 0;
• unsigned long nr_hugepages_after = 0;
• enum test_status status = TEST_SKIPPED;
• printf("Test Soft Offline When softoffline_corrected_errors=1\n");
• fd = create_hugetlbfs_file(&file_stat);
• if (fd < 0) {

• printf(EPREFIX "Failed to create hugetlbfs file\n");
  

• return status;
  

• }
• hugepagesize_kb = file_stat.f_bsize / 1024;
• printf(PREFIX "Hugepagesize is %ldkB\n", hugepagesize_kb);
• if (set_enable_soft_offline(1))

• return TEST_FAILED;
  

• if (read_nr_hugepages(hugepagesize_kb, &nr_hugepages_before) != 0)

• return TEST_FAILED;
  

• printf(PREFIX "Before MADV_SOFT_OFFLINE nr_hugepages=%ld\n",

• nr_hugepages_before);
  

• status = do_soft_offline(fd, 2 * file_stat.f_bsize, /*expect_ret=*/0);
• if (read_nr_hugepages(hugepagesize_kb, &nr_hugepages_after) != 0)

• return TEST_FAILED;
  

• printf(PREFIX "After MADV_SOFT_OFFLINE nr_hugepages=%ld\n",

• nr_hugepages_after);
  

• if (nr_hugepages_before != nr_hugepages_after + 1) {

• printf(EPREFIX "MADV_SOFT_OFFLINE should reduced 1 hugepage\n");
  

• return TEST_FAILED;
  

• }
• return status;

+}

+static enum test_status test_disable_soft_offline(void) +{

• int fd;
• struct statfs file_stat;
• unsigned long hugepagesize_kb = 0;
• unsigned long nr_hugepages_before = 0;
• unsigned long nr_hugepages_after = 0;
• enum test_status status = TEST_SKIPPED;
• printf("Test Soft Offline When softoffline_corrected_errors=0\n");
• fd = create_hugetlbfs_file(&file_stat);
• if (fd < 0) {

• printf(EPREFIX "Failed to create hugetlbfs file\n");
  

• return status;
  

• }
• hugepagesize_kb = file_stat.f_bsize / 1024;
• printf(PREFIX "Hugepagesize is %ldkB\n", hugepagesize_kb);
• if (set_enable_soft_offline(0))

• return TEST_FAILED;
  

• if (read_nr_hugepages(hugepagesize_kb, &nr_hugepages_before) != 0)

• return TEST_FAILED;
  

• printf(PREFIX "Before MADV_SOFT_OFFLINE nr_hugepages=%ld\n",

• nr_hugepages_before);
  

• status = do_soft_offline(fd, 2 * file_stat.f_bsize, /*expect_ret=*/EINVAL);
• if (read_nr_hugepages(hugepagesize_kb, &nr_hugepages_after) != 0)

• return TEST_FAILED;
  

• printf(PREFIX "After MADV_SOFT_OFFLINE nr_hugepages=%ld\n",

• nr_hugepages_after);
  

• if (nr_hugepages_before != nr_hugepages_after) {

• printf(EPREFIX "MADV_SOFT_OFFLINE reduced %lu hugepages\n",
  

• 	nr_hugepages_before - nr_hugepages_after);
  

• return TEST_FAILED;
  

• }
• return status;

+}

test_disable_soft_offline is almost same with test_soft_offline. Shall we extract the common pattern?

Thanks. .