Re: [PATCH v2 1/3] mm: hugetlb: disable freeing vmemmap pages when struct page crosses page boundaries

[Luis Chamberlain]

On Wed, Mar 02, 2022 at 04:37:56PM +0800, Muchun Song wrote:
> If CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON is enabled and the size
> of "struct page" is not power of two, we cannot optimize vmemmap pages
> of HugeTLB pages. We should disable this feature in this case.

The commit log does not descrie what happens if this is left enabled in
that case? Is this a fix? Why would it be a fix? Was something failing?
How did you spot this issue? What are the consequences of not applying
this patch?

  Luis