linux-kernel - Re: [PATCH v2 0/2] x86/mm: support memory-failure on 32-bits with SPARSEMEM

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Message-ID: <534dfba8-6222-4eea-aeb8-440d47c67f5b@kernel.org>
Date: Mon, 17 Nov 2025 14:03:46 +0100
From: "David Hildenbrand (Red Hat)" <david@...nel.org>
To: Xie Yuanbin <xieyuanbin1@...wei.com>, dave.hansen@...el.com
Cc: Liam.Howlett@...cle.com, akpm@...ux-foundation.org, bp@...en8.de,
 dave.hansen@...ux.intel.com, hpa@...or.com, liaohua4@...wei.com,
 lilinjie8@...wei.com, linmiaohe@...wei.com, linux-edac@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-mm@...ck.org,
 lorenzo.stoakes@...cle.com, luto@...nel.org, mhocko@...e.com,
 mingo@...hat.com, nao.horiguchi@...il.com, peterz@...radead.org,
 rppt@...nel.org, surenb@...gle.com, tglx@...utronix.de, tony.luck@...el.com,
 vbabka@...e.cz, will@...nel.org, x86@...nel.org
Subject: Re: [PATCH v2 0/2] x86/mm: support memory-failure on 32-bits with
 SPARSEMEM

On 17.11.25 03:09, Xie Yuanbin wrote:
> On Wed, 5 Nov 2025 17:05:36 +0800, Xie Yuanbin wrote:
>> On Wed, 5 Nov 2025 09:12:04 +0100, Dave Hansen wrote:
>>> Let me clarify what we need to know:
>>>
>>> Will you (or your employer) be running such updated 32bit kernels on
>>> hardware that supports MCEs.
>>>
>>> In other words: is this change driver by *real demand*
>>
>> Thanks! Asking like this, I completely understand now.
>>
>> We won't directly upgrade the kernel to 6.18.x (or later versions) to use
>> this feature, but if Linux community approves these patches, we will
>> backport it to 5.10.x and use it. I know that the page-flags in 5.10.x
>> have been exhausted, but we can work around them by adjusting
>> SECTION_SIZE_BITS/MAX_PHYSMEM_BITS to free up a page flag.
>> Another patch I submitted for arm32:
>> Link: https://lore.kernel.org/20250922021453.3939-1-xieyuanbin1@huawei.com
>> , follows the same logic.
>>
>> Currently, there is a clear demand for ARM32, while the demand for x86 is
>> still under discussion.
>>
>>> or just by "oh
>>> look, we can enable that now, I can come up with a theoretical use case
>>> but I don't know if anybody would actually care"?
>>
>> It can also be said that way. In fact, when developing the demand
>> "support MEMORY_FAILURE for 32-bit OS" in version 5.10.x, I found that the
>> latest version already supported this feature, so I submitted these
>> patches, and hope others can benefit from it as well.
> 
> Hello, David Hildenbrand and Dave Hansen!
> 
> Do you have any other comments on this patch? If you think that
> supporting memory-failure on x86_32 is meaningless, I will only submit
> patch 2 in the v3 patches.

I'd say, if nobody will really make use of that right now (customer 
request etc), just leave x86 alone for now.

-- 
Cheers

David