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From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Lorenzo Stoakes <ljs@kernel.org>, Wei Yang <richard.weiyang@gmail.com>
Cc: akpm@linux-foundation.org, riel@surriel.com, liam@infradead.org,
	vbabka@kernel.org, harry@kernel.org, jannh@google.com,
	willy@infradead.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, lance.yang@linux.dev
Subject: Re: [PATCH] mm/page_vma_mapped: guard check_pmd() with CONFIG_TRANSPARENT_HUGEPAGE
Date: Thu, 25 Jun 2026 15:49:59 +0200	[thread overview]
Message-ID: <c66f4bec-0933-401b-bf2f-a1b2e256023f@kernel.org> (raw)
In-Reply-To: <aj0vjdBN-oNMI2yI@lucifer>

On 6/25/26 15:45, Lorenzo Stoakes wrote:
> On Wed, Jun 24, 2026 at 08:23:59AM +0000, Wei Yang wrote:
>> The kernel test robot reported a build failure on the parisc architecture
>> when expanding HPAGE_PMD_NR in check_pmd().
> 
> Let me first say that I absolutely hate that we continue to support museum
> piece architectures to the point that we have to make changes in core code
> to accommodate them.

I wonder why we shouldn't be able to trigger that on other archs with
!CONFIG_TRANSPARENT_HUGEPAGE ?

I think the code just relies on pmd_trans_huge() == false, and consequently
check_pmd will get compiled out completely.

Now, the report was against Wei's new patch.

There is *nothing* to be fixed for existing code.


Fixes: 2aff7a4755be ("mm: Convert page_vma_mapped_walk to work on PFNs")

is just wrong?

-- 
Cheers,

David


  reply	other threads:[~2026-06-25 13:50 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-24  8:23 [PATCH] mm/page_vma_mapped: guard check_pmd() with CONFIG_TRANSPARENT_HUGEPAGE Wei Yang
2026-06-24 20:14 ` Andrew Morton
2026-06-25  3:46   ` Wei Yang
2026-06-25  4:59     ` Andrew Morton
2026-06-25  6:41       ` Wei Yang
2026-06-25 13:51         ` Lorenzo Stoakes
2026-06-26  0:08         ` Balbir Singh
2026-06-25 13:45 ` Lorenzo Stoakes
2026-06-25 13:49   ` David Hildenbrand (Arm) [this message]
2026-06-25 14:02     ` Lorenzo Stoakes
2026-06-25 14:30       ` David Hildenbrand (Arm)
2026-06-25 16:18         ` Wei Yang
2026-06-25 23:13           ` Wei Yang

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