Re: [PATCH v4 3/6] mm/sparse-vmemmap: drop Device DAX-specific population path

On Oct 10, 2026, at 15:57, Muchun Song [off-list ref] wrote:

The common vmemmap path selects the shared page for optimized mappings
itself, so Device DAX no longer needs vmemmap_populate_compound_pages()
to find a shared tail page and pass its backing PFN through the generic
population helpers.

Remove the Device DAX-specific population path and let section memmap
population always use vmemmap_populate(). The powerpc retains an
architecture-specific compound-page implementation, so select it directly
from radix__vmemmap_populate() for optimizable sections.

Regarding the issue mentioned by Sashiko [1], it does exist, but it
was not introduced by this series. I have already fixed it in another
series [2], but it has not been merged yet.

[1] https://sashiko.dev/#/patchset/20261010075755.83339-1-songmuchun%40bytedance.com?part=3
[2] https://lore.kernel.org/all/20260924025035.1265035-1-songmuchun@bytedance.com/ (local)

Thanks.