Re: [PATCH v5] page_alloc: allow migration of smaller hugepages during contig_alloc

[Gregory Price]

On Thu, Dec 18, 2025 at 04:17:14PM -0500, Zi Yan wrote:
> On 18 Dec 2025, at 15:42, Gregory Price wrote:
> 
> OK, you assume hugetlb is harder to migrate compared to other movable pages.
> Considering the limited number of hugetlb pages, it is quite possible.
> Anyway, I will wait for your v6. Thank you for the explanation and the
> prototype below.
> 

They are harder - a migration starts with an allocation. Contiguous
allocations may then cause more migrations. We can end back up in similar
style search/migrate code.

Basically this can go some amount of recursive (though not much in practice).

We at least guarantee termination because we guarantee we won't attempt to
move pages of the same size or larger than the current allocation.

~Gregory