On 9/19/26 8:24 AM, Kiryl Shutsemau wrote:
From: "Kiryl Shutsemau (Meta)" <[email protected]> The mthp_khugepaged context runs the generic cases at a sub-PMD order, which answers how many folios of that order a range ends up with. It cannot say which order-sized window they landed in, so "the populated window collapsed" and "the empty window next to it collapsed instead" look alike. Add four cases that check each window on its own, with the folio-order helpers in vm_util: - collapse_order_single_window(): only the populated window collapses; - collapse_order_partial_window(): the default max_ptes_none lets a window with one present PTE collapse; - collapse_order_max_ptes_none(): with max_ptes_none=0 a full window collapses and one missing a page does not; - collapse_order_mixed_sources(): sources that are already large folios of a smaller order collapse to the target. Each case faults its region before MADV_HUGEPAGE with only the target order enabled, so the sources are order 0 and the result can only come from khugepaged. They wait for a full pass rather than for the result to appear: without a completed pass, "not collapsed" and "not scanned yet" are the same thing. Assisted-by: LLM Tested-by: Muhammad Usama Anjum <[email protected]> Signed-off-by: Kiryl Shutsemau (Meta) <[email protected]> ---
Tested-by: Baolin Wang <[email protected]>
