On Thu, Sep 10, 2026 at 01:09:00PM +0800, Baolin Wang wrote: > > > On 9/8/26 8:50 PM, Kiryl Shutsemau wrote: > > From: "Kiryl Shutsemau (Meta)" <[email protected]> > > > > collapse_order_mixed_sources() faults its region as order-2 folios and > > collapses them to the -c target. Order 2 is below the contpte size on > > every arm64 page size, so nothing in this suite collapses a contpte-mapped > > source on purpose. > > > > Let -s name the source order alongside -c. The case then faults at that > > order, keeping order 2 when -s is absent, and the source order has to be a > > supported mTHP order below the target. The other mTHP cases are > > unaffected: mthp_push_target_order() enables only the target order. > > > > "-s 5 -c 7" on arm64/64K then collapses contpte-mapped sources into a > > larger mTHP. > > Make sense. But we should validate invalid parameter combinations for '-s' > and '-c'. For example, when I set the following unreasonable parameters, > some test cases fail, so such invalid configurations should be rejected.
Patch 14 adds that check; with the whole series applied, "-s 7 -c 6 mthp_khugepaged:anon" stops before running anything: 1..0 # SKIP -c 6 needs a source order below it, -s says 7 So this is a minor bisectability issue: the check should have come with this patch rather than two later. I will move it here if the series gets respun. -- Kiryl Shutsemau / Kirill A. Shutemov
