Re: [PATCH mm-unstable v18 07/14] mm/khugepaged: skip collapsing mTHP to smaller orders

From: David Hildenbrand (Arm)

Date: Fri May 22 2026 - 17:52:24 EST


On 5/22/26 17:00, Nico Pache wrote:
> khugepaged may try to collapse a mTHP to a smaller mTHP, resulting in
> some pages being unmapped.

The "some pages being unmapped" part is unclear.

I assume what you mean is "possibly resulting in a partially mapped source
folio, which is undesired."

But there is also the problem that we could try collapsing a folio to a
same-sized folio, which doesn't make sense (assuming the folio is fully mapped).

Clarify all that, please.

Acked-by: David Hildenbrand (arm) <david@xxxxxxxxxx>

--
Cheers,

David