On 07.11.25 09:00, Sourabh Jain wrote:

On 06/11/25 20:32, David Hildenbrand (Red Hat) wrote:

quoted

quoted

quoted

Yes, we discussed that in [1].

We'll have to set ARCH_HAS_GIGANTIC_PAGE on ppc and increase
MAX_FOLIO_ORDER, because apparently, there might be ppc configs that
have even larger hugetlb sizes than PUDs.

@Cristophe, I was under the impression that you would send a fix. Do
you
want me to prepare something and send it out?

Indeed I would have liked to better understand the implications of all
this, but I didn't have the time.

Indeed, too me longer than it should to understand and make up my mind
as well.

quoted

By the way, you would describe the fix better than me so yes if you can
prepare and send a fix please do.

I just crafted the following. I yet have to test it more, some early
feedback+testing would be appreciated!

 From 274928854644c49c92515f8675c090dba15a0db6 Mon Sep 17 00:00:00 2001
From: "David Hildenbrand (Red Hat)" <david@kernel.org>
Date: Thu, 6 Nov 2025 11:31:45 +0100
Subject: [PATCH] mm: fix MAX_FOLIO_ORDER on some ppc64 configs with
hugetlb

b4 did not detect this patch, and manually copying the patch text from this
reply also did not apply cleanly on upstream master and linuxppc
master/next.

I have it on a branch here:

https://github.com/davidhildenbrand/linux/commit/274928854644c49c92515f8675c090dba15a0db6

https://github.com/davidhildenbrand/linux.git max_folio_order

-- 
Cheers

David