From: Shivam Kalra <[email protected]> Add focused coverage for the folio_check_splittable() eligibility checks. Verify that an ordinary mappingless folio is rejected, a mappingless swapcache folio is accepted, and unsupported target orders and split types remain rejected.
Build the test only when KUnit is built in because folio_check_splittable() is intentionally not exported. Signed-off-by: Shivam Kalra <[email protected]> --- mm/Kconfig | 14 ++++++++++++ mm/Makefile | 1 + mm/tests/folio_split_kunit.c | 52 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 67 insertions(+) diff --git a/mm/Kconfig b/mm/Kconfig index 331daf7fcfab..164dc1438900 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1503,6 +1503,20 @@ config LAZY_MMU_MODE_KUNIT_TEST If unsure, say N. +config FOLIO_SPLIT_KUNIT_TEST + bool "KUnit tests for folio splitting" if !KUNIT_ALL_TESTS + depends on KUNIT=y + depends on TRANSPARENT_HUGEPAGE + depends on SWAP + default KUNIT_ALL_TESTS + help + Enable this option to test folio split eligibility checks. The tests + verify support for mappingless folios in the swap cache and ensure + that unsupported target orders and split types are still rejected. + The tests are built into the kernel and run during KUnit execution. + + If unsure, say N. + source "mm/damon/Kconfig" endmenu diff --git a/mm/Makefile b/mm/Makefile index ab37ef428d98..f09057b40e1a 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -146,4 +146,5 @@ obj-$(CONFIG_SHRINKER_DEBUG) += shrinker_debug.o obj-$(CONFIG_EXECMEM) += execmem.o obj-$(CONFIG_TMPFS_QUOTA) += shmem_quota.o obj-$(CONFIG_LAZY_MMU_MODE_KUNIT_TEST) += tests/lazy_mmu_mode_kunit.o +obj-$(CONFIG_FOLIO_SPLIT_KUNIT_TEST) += tests/folio_split_kunit.o obj-$(CONFIG_MEM_ALLOC_PROFILING) += alloc_tag.o diff --git a/mm/tests/folio_split_kunit.c b/mm/tests/folio_split_kunit.c new file mode 100644 index 000000000000..f91c1a320bbf --- /dev/null +++ b/mm/tests/folio_split_kunit.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <kunit/test.h> +#include <linux/errno.h> +#include <linux/mm.h> +#include <linux/huge_mm.h> +#include <linux/module.h> +#include <linux/pagemap.h> + +static void folio_check_splittable_mappingless_swapcache(struct kunit *test) +{ + struct folio *folio; + int ret; + + folio = folio_alloc(GFP_KERNEL, 2); + KUNIT_ASSERT_NOT_NULL(test, folio); + folio_lock(folio); + + KUNIT_EXPECT_PTR_EQ(test, folio->mapping, NULL); + ret = folio_check_splittable(folio, 0, SPLIT_TYPE_UNIFORM); + KUNIT_EXPECT_EQ(test, ret, -EBUSY); + + /* Only the eligibility check is exercised here. */ + folio_set_swapbacked(folio); + folio_set_swapcache(folio); + + ret = folio_check_splittable(folio, 0, SPLIT_TYPE_UNIFORM); + KUNIT_EXPECT_EQ(test, ret, 0); + ret = folio_check_splittable(folio, 1, SPLIT_TYPE_UNIFORM); + KUNIT_EXPECT_EQ(test, ret, -EINVAL); + ret = folio_check_splittable(folio, 0, SPLIT_TYPE_NON_UNIFORM); + KUNIT_EXPECT_EQ(test, ret, -EINVAL); + + folio_clear_swapcache(folio); + folio_clear_swapbacked(folio); + folio_unlock(folio); + folio_put(folio); +} + +static struct kunit_case folio_split_test_cases[] = { + KUNIT_CASE(folio_check_splittable_mappingless_swapcache), + {} +}; + +static struct kunit_suite folio_split_test_suite = { + .name = "folio_split", + .test_cases = folio_split_test_cases, +}; + +kunit_test_suite(folio_split_test_suite); + +MODULE_DESCRIPTION("Tests for folio splitting"); +MODULE_LICENSE("GPL"); -- 2.43.0
