Re: [PATCH v7 02/12] mm/sparsemem: Introduce common definitions for the size and mask of a section

[Oscar Salvador]

On Wed, May 01, 2019 at 10:55:32PM -0700, Dan Williams wrote:
> Up-level the local section size and mask from kernel/memremap.c to
> global definitions.  These will be used by the new sub-section hotplug
> support.
> 
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Jérôme Glisse <jglisse@xxxxxxxxxx>
> Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> ---
>  include/linux/mmzone.h |    2 ++
>  kernel/memremap.c      |   10 ++++------
>  mm/hmm.c               |    2 --
>  3 files changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index f0bbd85dc19a..6726fc175b51 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -1134,6 +1134,8 @@ static inline unsigned long early_pfn_to_nid(unsigned long pfn)
>   * PFN_SECTION_SHIFT		pfn to/from section number
>   */
>  #define PA_SECTION_SHIFT	(SECTION_SIZE_BITS)
> +#define PA_SECTION_SIZE		(1UL << PA_SECTION_SHIFT)
> +#define PA_SECTION_MASK		(~(PA_SECTION_SIZE-1))

As discussed here [1], we do not need the new PA_SECTION_MASK if we work with
pfns/pages directly, so I'd drop it if you go that way.

Besides that:

Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>

[1] https://patchwork.kernel.org/patch/10926047/

-- 
Oscar Salvador
SUSE L3