Re: [RFC PATCH 00/15] Make MAX_ORDER adjustable as a kernel boot time parameter.

From: Vlastimil Babka
Date: Fri Aug 06 2021 - 11:39:14 EST

On 8/5/21 9:02 PM, Zi Yan wrote:
> From: Zi Yan <ziy@xxxxxxxxxx>

> Patch 3 restores the pfn_valid_within() check when buddy allocator can merge
> pages across memory sections. The check was removed when ARM64 gets rid of holes
> in zones, but holes can appear in zones again after this patchset.

To me that's most unwelcome resurrection. I kinda missed it was going away and
now I can't even rejoice? I assume the systems that will be bumping max_order
have a lot of memory. Are they going to have many holes? What if we just
sacrificed the memory that would have a hole and don't add it to buddy at all?