From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 90E3F1EF09B; Thu, 15 Jan 2026 18:18:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768501139; cv=none; b=Ykmk9jOl7va7Ru+eZWndSebJcD17gyje5zUNJWS5v+BsjGTH1eZG5rkKye1Ap2RRGX8CYBto6tTuO+IgTyxypKr4b8OYimn98NWDjCaPbPzCALmy4JsTOHDjGJARt8NNQeVj8c3Z6bJqoGSsKfygG6F3GEfy5KDlb9AdRx6pjxc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768501139; c=relaxed/simple; bh=OoxN+wiYLUXA84AAEzLFYI4Crg2HGDqLMAG7AyG/Wk0=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=p0dYQKRwDQ4+gbUgSfmfOH77iDNmBrHU5H3o6j791kgAeeHJGivaP6uRWr9wGT0lbTEjsb96BYgmbDlOWslH7SkeVHvJmLMtUfa0wR32qtHTZcEEXXMSeiFcNmTmydLJA+GoumIkmqz8oxMr7fTW6v74IEBGEIFSFVBwpertqqU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=e814AiMP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="e814AiMP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA2EDC116D0; Thu, 15 Jan 2026 18:18:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1768501139; bh=OoxN+wiYLUXA84AAEzLFYI4Crg2HGDqLMAG7AyG/Wk0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=e814AiMP04MGQQdvcF/eHiGR3mf/DMRLiaDPWrPEkG74cX3rRLhEga06ol//9OChC vkULXBUpl0DbaS8P8n8lV4PmH+yaM1LyzgRYvkc1THr/VqmymRuJ47mo/jn4h8uQVB 1kwCMTpAMOChF+x4dKZrsq1Dv3Akpd17X8oldoso= Date: Thu, 15 Jan 2026 10:18:58 -0800 From: Andrew Morton To: Cui Chao Cc: Jonathan Cameron , Mike Rapoport , Wang Yinfeng , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 1/1] mm: numa_memblks: Identify the accurate NUMA ID of CFMW Message-Id: <20260115101858.85fd7b8e837c1c92a4fdc5f0@linux-foundation.org> In-Reply-To: <9132054c-3017-4af0-84e0-e4359b0794a6@phytium.com.cn> References: <20260106031042.1606729-1-cuichao1753@phytium.com.cn> <20260106031042.1606729-2-cuichao1753@phytium.com.cn> <20260108094812.8757ce3ad8370668eaafb29c@linux-foundation.org> <9132054c-3017-4af0-84e0-e4359b0794a6@phytium.com.cn> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 15 Jan 2026 17:43:02 +0800 Cui Chao 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.