[PATCH v2 48/53] selftests/mm: uffd-unit-tests: add setup of HugeTLB pages

Mike Rapoport
2026-04-18T11:00:48Z

uffd-unit-tests skips HugeTLB tests if there are no free huge pages
prepared by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Replace exit() calls with _exit() to avoid restoring HugeTLB settings in
the middle of test.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
tools/testing/selftests/mm/uffd-unit-tests.c | 31 +++++++++++++++++---
1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c
index 1a33db281f8a..20e1829db91f 100644
--- a/tools/testing/selftests/mm/uffd-unit-tests.c
+++ b/tools/testing/selftests/mm/uffd-unit-tests.c
@@ -305,7 +305,7 @@ static int pagemap_test_fork(uffd_global_test_opts_t *gopts, bool with_event, bo
if (test_pin)
unpin_pages(&args);
/* Succeed */
- exit(0);
+ _exit(0);
}
waitpid(child, &result, 0);

@@ -773,7 +773,7 @@ static void uffd_sigbus_test_common(uffd_global_test_opts_t *gopts, bool wp)
err("fork");

if (!pid)
- exit(faulting_process(gopts, 2, wp));
+ _exit(faulting_process(gopts, 2, wp));

waitpid(pid, &err, 0);
if (err)
@@ -827,7 +827,7 @@ static void uffd_events_test_common(uffd_global_test_opts_t *gopts, bool wp)
err("fork");

if (!pid)
- exit(faulting_process(gopts, 0, wp));
+ _exit(faulting_process(gopts, 0, wp));

waitpid(pid, &err, 0);
if (err)
@@ -1706,11 +1706,32 @@ static int uffd_count_tests(int n_tests, int n_mems, const char *test_filter)
return count;
}

+static unsigned long uffd_setup_hugetlb(void)
+{
+ unsigned long nr_hugepages, hp_size;
+
+ hugetlb_save_settings();
+ hp_size = default_huge_page_size();
+
+ if (!hp_size)
+ return 0;
+
+ /* need twice UFFD_TEST_MEM_SIZE, one for src area and one for dst */
+ nr_hugepages = 2 * MAX(UFFD_TEST_MEM_SIZE, hp_size * 2) / hp_size;
+ hugetlb_set_nr_default_pages(nr_hugepages);
+
+ if (hugetlb_free_default_pages() < nr_hugepages)
+ return 0;
+
+ return hp_size;
+}
+
int main(int argc, char *argv[])
{
int n_tests = sizeof(uffd_tests) / sizeof(uffd_test_case_t);
int n_mems = sizeof(mem_types) / sizeof(mem_type_t);
const char *test_filter = NULL;
+ unsigned long hugepage_size;
bool list_only = false;
uffd_test_case_t *test;
mem_type_t *mem_type;
@@ -1745,6 +1766,8 @@ int main(int argc, char *argv[])
return KSFT_PASS;
}

+ hugepage_size = uffd_setup_hugetlb();
+
ksft_print_header();
ksft_set_plan(uffd_count_tests(n_tests, n_mems, test_filter));

@@ -1771,7 +1794,7 @@ int main(int argc, char *argv[])
uffd_test_case_ops = test->test_case_ops;

if (mem_type->mem_flag & (MEM_HUGETLB_PRIVATE | MEM_HUGETLB)) {
- gopts.page_size = default_huge_page_size();
+ gopts.page_size = hugepage_size;
if (gopts.page_size == 0) {
uffd_test_skip("huge page size is 0, feature missing?");
continue;
--
2.53.0