linux-kernel - Re: [PATCH v2 1/1] mm: numa_memblks: Identify the accurate NUMA ID of CFMW

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20260115101858.85fd7b8e837c1c92a4fdc5f0@linux-foundation.org>
Date: Thu, 15 Jan 2026 10:18:58 -0800
From: Andrew Morton <akpm@...ux-foundation.org>
To: Cui Chao <cuichao1753@...tium.com.cn>
Cc: Jonathan Cameron <Jonathan.Cameron@...wei.com>, Mike Rapoport
 <rppt@...nel.org>, Wang Yinfeng <wangyinfeng@...tium.com.cn>,
 linux-cxl@...r.kernel.org, linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH v2 1/1] mm: numa_memblks: Identify the accurate NUMA ID
 of CFMW

On Thu, 15 Jan 2026 17:43:02 +0800 Cui Chao <cuichao1753@...tium.com.cn> wrote:

> When a CXL RAM region is created in userspace, the memory capacity of 
> the newly created region is not added to the CFMW-dedicated NUMA node. 
> Instead, it is accumulated into an existing NUMA node (e.g., NUMA0 
> containing RAM). This makes it impossible to clearly distinguish between 
> the two types of memory, which may affect memory-tiering applications.
> 

OK, thanks, I added this to the changelog.  Please retain it when
sending v3.

What I'm actually looking for here are answers to the questions

  Should we backport this into -stable kernels and if so, why?
  And if not, why not?

So a very complete description of the runtime effects really helps
myself and others to decide which kernels to patch.  And it helps
people to understand *why* we made that decision.

And sorry, but "may affect memory-tiering applications" isn't very
complete!

So please, tell us how much our users are hurting from this and please
make a recommendation on the backporting decision.