This patchset uses kpageflags to get after-split folio orders for a better split_huge_page_test result check[1]. The added gather_folio_orders() scans through a VPN range and collects the numbers of folios at different orders. check_folio_orders() compares the result of gather_folio_orders() to a given list of numbers of different orders.
This patchset also added new order and in folio offset to the split huge page debugfs's pr_debug()s; Changelog === >From V2[3]: 1. Added two missing free()s in check_folio_orders(). 2. Reimplemented is_backed_by_thp() to use kpageflags to get precise folio order information and renamed it to is_backed_by_folio() in new Patch 3. 3. Renamed *_file to *_fd in Patch 2. 4. Indentation fixes. 5. Fixed vaddr stepping issue in gather_folio_orders() when a compound tail page is encountered. 6. Used pmd_order in place of max_order in split_huge_page_test.c. 7. Documented gather_folio_orders(). >From V1[2]: 1. Dropped split_huge_pages_pid() for loop step change to avoid messing up with PTE-mapped THP handling. split_huge_page_test.c is changed to perform split at [addr, addr + pagesize) range to limit one folio_split() per folio. 2. Moved pr_debug changes in Patch 2 to Patch 1. 3. Moved KPF_* to vm_util.h and used PAGEMAP_PFN instead of local PFN_MASK. 4. Used pagemap_get_pfn() helper. 5. Used char *vaddr and size_t len as inputs to gather_folio_orders() and check_folio_orders() instead of vpn and nr_pages. 6. Removed variable length variables and used malloc instead. [1] https://lore.kernel.org/linux-mm/e2f32bdb-e4a4-447c-867c-31405cbba...@redhat.com/ [2] https://lore.kernel.org/linux-mm/20250806022045.342824-1-...@nvidia.com/ [3] https://lore.kernel.org/linux-mm/20250808190144.797076-1-...@nvidia.com/ Zi Yan (4): mm/huge_memory: add new_order and offset to split_huge_pages*() pr_debug. selftests/mm: add check_folio_orders() helper. selftests/mm: reimplement is_backed_by_thp() with more precise check selftests/mm: check after-split folio orders in split_huge_page_test. mm/huge_memory.c | 8 +- .../selftests/mm/split_huge_page_test.c | 154 +++++++++++----- tools/testing/selftests/mm/vm_util.c | 173 ++++++++++++++++++ tools/testing/selftests/mm/vm_util.h | 8 + 4 files changed, 292 insertions(+), 51 deletions(-) -- 2.47.2
