Add regression and new tests when hugepage has correctable memory
errors, and how userspace wants to deal with it:
* if enable_soft_offline=1, mapped hugepage is soft offlined
* if enable_soft_offline=0, mapped hugepage is intact
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@xxxxxxxxxx>
---
tools/testing/selftests/mm/.gitignore | 1 +
tools/testing/selftests/mm/Makefile | 1 +
.../selftests/mm/hugetlb-soft-offline.c | 228 ++++++++++++++++++
tools/testing/selftests/mm/run_vmtests.sh | 4 +
4 files changed, 234 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..cde82705499b
--- /dev/null
+++ b/tools/testing/selftests/mm/hugetlb-soft-offline.c
@@ -0,0 +1,228 @@
+// 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)) {
+ 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();
+}
diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index 3157204b9047..781117fac1ba 100755
--- a/tools/testing/selftests/mm/run_vmtests.sh
+++ b/tools/testing/selftests/mm/run_vmtests.sh
@@ -331,6 +331,10 @@ CATEGORY="hugetlb" run_test ./thuge-gen
CATEGORY="hugetlb" run_test ./charge_reserved_hugetlb.sh -cgroup-v2
CATEGORY="hugetlb" run_test ./hugetlb_reparenting_test.sh -cgroup-v2
if $RUN_DESTRUCTIVE; then
+nr_hugepages_tmp=$(cat /proc/sys/vm/nr_hugepages)
+echo 8 > /proc/sys/vm/nr_hugepages
+CATEGORY="hugetlb" run_test ./hugetlb-soft-offline
+echo "$nr_hugepages_tmp" > /proc/sys/vm/nr_hugepages
CATEGORY="hugetlb" run_test ./hugetlb-read-hwpoison
fi
--
2.45.2.741.gdbec12cfda-goog
