Re: [PATCH 2/2] mm/hugetlb: pass correct order_per_bit to cma_declare_contiguous_nid

[Roman Gushchin]

On Thu, Apr 04, 2024 at 04:25:15PM +0000, Frank van der Linden wrote:
> The hugetlb_cma code passes 0 in the order_per_bit argument to
> cma_declare_contiguous_nid (the alignment, computed using the
> page order, is correctly passed in).
> 
> This causes a bit in the cma allocation bitmap to always represent
> a 4k page, making the bitmaps potentially very large, and slower.
> 
> So, correctly pass in the order instead.
> 
> Signed-off-by: Frank van der Linden <fvdl@xxxxxxxxxx>
> Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
> Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma")

Hi Frank,

there is a comment just above your changes which explains why order_per_bit is 0.
Is this not true anymore? If so, please, fix the comment too. Please, clarify.

Thanks!