Re: [PATCH mm-unstable v19 05/14] mm/khugepaged: require collapse_huge_page to enter/exit with the lock dropped

[Lance Yang]

On Fri, Jun 05, 2026 at 10:14:12AM -0600, Nico Pache wrote:
>Currently the collapse_huge_page function requires the mmap_read_lock to
>enter with it held, and exit with it dropped. This function moves the
>unlock into its parent caller, and changes this semantic to requiring it
>to enter/exit with it always unlocked.
>
>In future patches, we need this expectation, as for in mTHP collapse, we
>may have already dropped the lock, and do not want to conditionally
>check for this by passing through the lock_dropped variable.
>
>No functional change is expected as one of the first things the
>collapse_huge_page function does is drop this lock before allocating the
>hugepage.
>
>Reviewed-by: Lorenzo Stoakes <ljs@xxxxxxxxxx>
>Acked-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
>Signed-off-by: Nico Pache <npache@xxxxxxxxxx>
>---

Reviewed-by: Lance Yang <lance.yang@xxxxxxxxx>