From: "Kiryl Shutsemau (Meta)" <[email protected]> The mm selftests had two ways to check that a range came out as folios of a given order. check_huge_anon() and check_huge_file() counted folios of the order in the range. is_range_backed_by_order() checked each window for a folio with its head at the window start. Baolin found the two sets in khugepaged.c confusing [1], and the answer at the time was to merge them once Yeoreum's rewrite of check_huge_*() on top of pagemap and kpageflags landed. It is in mm-new now.
Make check_huge() check windows below the PMD size, route every caller through it, and make is_range_backed_by_order() an internal of vm_util.c. The split test's count-based check goes the same way, which also makes it notice a split at the wrong offset. On the way check_huge() stops reopening pagemap and kpageflags on every call, which was the other reason the separate helper existed. Tested on mm-new 2589c5593c20 with KASAN, in 16G guests, x86-64/4K under KVM and arm64/64K under TCG: the khugepaged matrix at every order, split_huge_page_test, pagemap_ioctl and khugepaged all:all on tmpfs pass with the same counts as before. [1] https://lore.kernel.org/all/[email protected]/ Kiryl Shutsemau (Meta) (4): selftests/mm: open pagemap and kpageflags once for check_huge() selftests/mm: check sub-PMD ranges window by window in check_huge() selftests/mm: check collapse results through check_huge() only selftests/mm: check split results by position, drop gather_folio_orders() .../testing/selftests/mm/folio_order_check.c | 28 +- tools/testing/selftests/mm/khugepaged.c | 47 ++- .../selftests/mm/khugepaged_sync_check.c | 7 +- .../selftests/mm/split_huge_page_test.c | 104 +++--- tools/testing/selftests/mm/vm_util.c | 320 ++++++------------ tools/testing/selftests/mm/vm_util.h | 7 +- 6 files changed, 176 insertions(+), 337 deletions(-) base-commit: 2589c5593c200e5146db848730baa1d7dd0c9f4e -- 2.54.0
