Add test for partial mlock on THP which exercises walk_page_range() with a subset of the THP. This should trigger a PMD split since mlock operates at page granularity.
Signed-off-by: Usama Arif <[email protected]> --- .../testing/selftests/mm/thp_pmd_split_test.c | 26 +++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/tools/testing/selftests/mm/thp_pmd_split_test.c b/tools/testing/selftests/mm/thp_pmd_split_test.c index 4944a5a516da9..3c9f05457efec 100644 --- a/tools/testing/selftests/mm/thp_pmd_split_test.c +++ b/tools/testing/selftests/mm/thp_pmd_split_test.c @@ -177,4 +177,30 @@ TEST_F(thp_pmd_split, partial_mprotect) self->split_pmd_failed_before); } +/* + * Partial mlock triggering split (walk_page_range) + * + * Tests mlock on a partial THP region which should trigger a PMD split. + */ +TEST_F(thp_pmd_split, partial_mlock) +{ + int ret; + + ret = allocate_thp(self->aligned, self->pmdsize); + if (ret) + SKIP(return, "Failed to allocate THP"); + + /* Partial mlock - should trigger PMD split */ + ret = mlock((char *)self->aligned + self->pagesize, self->pagesize); + if (ret && errno == ENOMEM) + SKIP(return, "mlock failed with ENOMEM (resource limit)"); + ASSERT_EQ(ret, 0); + + /* Cleanup */ + munlock((char *)self->aligned + self->pagesize, self->pagesize); + + log_and_check_pmd_split(_metadata, self->split_pmd_before, + self->split_pmd_failed_before); +} + TEST_HARNESS_MAIN -- 2.47.3
