Re: [PATCH v3 2/6] mm/sparse-vmemmap: support device DAX in common vmemmap path

[Lance Yang]

On Tue, Sep 29, 2026 at 01:32:27PM +0800, Muchun Song wrote:
>The common vmemmap population path cannot yet handle optimized Device DAX
>mappings on its own. It uses pfn_to_zone() to find the shared tail page,
>but Device DAX populates its vmemmap at runtime before the ZONE_DEVICE span
>is initialized.
>
>Teach the common path to use device_zone() for runtime optimized vmemmap
>population while retaining pfn_to_zone() for early boot. This allows the
>same path to support both early boot mappings and Device DAX.
>
>The backing PFN supplied by the Device DAX-specific population path is no
>longer used, allowing the redundant lookup and population code to be
>removed later.
>
>Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
>Acked-by: Qi Zheng <qi.zheng@xxxxxxxxx>
>---

Nothing jumped out at me, feel free to add:

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