Re: [PATCH v7 03/12] mm/sparsemem: Add helpers track active portions of a section at boot

[Pavel Tatashin]

On 19-05-01 22:55:37, Dan Williams wrote:
> Prepare for hot{plug,remove} of sub-ranges of a section by tracking a
> section active bitmask, each bit representing 2MB (SECTION_SIZE (128M) /
> map_active bitmask length (64)). If it turns out that 2MB is too large
> of an active tracking granularity it is trivial to increase the size of
> the map_active bitmap.
> 
> The implications of a partially populated section is that pfn_valid()
> needs to go beyond a valid_section() check and read the sub-section
> active ranges from the bitmask.
> 
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
> Tested-by: Jane Chu <jane.chu@xxxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>

Hi Dan,

I have sent comments to the previous version of this patch:
https://lore.kernel.org/lkml/CA+CK2bAfnCVYz956jPTNQ+AqHJs7uY1ZqWfL8fSUFWQOdKxHcg@xxxxxxxxxxxxxx/

I think they still apply to this one.

Thank you,
Pasha