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From: Gregory Price <gourry@gourry.net>
To: Kai Huang <kai.huang@intel.com>
Cc: rafael@kernel.org, lenb@kernel.org, dan.j.williams@intel.com,
	alison.schofield@intel.com, akpm@linux-foundation.org,
	nunodasneves@linux.microsoft.com, xueshuai@linux.alibaba.com,
	thorsten.blum@linux.dev, wangyuquan1236@phytium.com.cn,
	linux-acpi@vger.kernel.org, linux-cxl@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ACPI: NUMA: Only parse CFMWS at boot when CXL_ACPI is on
Date: Wed, 4 Mar 2026 17:33:26 -0500	[thread overview]
Message-ID: <aaizNh-0LEvRQMCy@gourry-fedora-PF4VCD3F> (raw)
In-Reply-To: <20260304213342.5776-1-kai.huang@intel.com>

On Thu, Mar 05, 2026 at 10:33:42AM +1300, Kai Huang wrote:
> Increasing the 'nr_node_ids' has side effects.  For instance, it is
> widely used by the kernel for "highest possible NUMA node" based memory
> allocations.  It also impacts userspace ABIs, e.g., some NUMA memory
> related system calls such as 'get_mempolicy' which requires 'maxnode'
> not being smaller than the 'nr_node_ids'.
> 

Is this a Linux issue or a Firmware issue?

Is GNR exporting more CFMWS than it should?

Is your SRAT missing entries for CFMWS that are otherwise present?

Are the CFMWS empty? (is that even valid)

> E.g., on the aforementioned GNR platform, the "Slab" in /proc/meminfo is
> reduced with this change (when CXL_ACPI is off):
> 
> 	w/ this change		w/o
> 
> Slab	900488 kB		923660 kB
> 

This is a good effect, but I still question the premise.

We don't usually want #ifdef's inside of .c files if we can avoid it.

~Gregory

  reply	other threads:[~2026-03-04 22:33 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-04 21:33 [PATCH] ACPI: NUMA: Only parse CFMWS at boot when CXL_ACPI is on Kai Huang
2026-03-04 22:33 ` Gregory Price [this message]
2026-03-04 23:20   ` Alison Schofield
2026-03-04 23:56     ` Gregory Price
2026-03-05  0:14       ` Huang, Kai
2026-03-05  0:29         ` Gregory Price
2026-03-05  0:45           ` Huang, Kai
2026-03-05  1:05             ` Gregory Price
2026-03-05  1:29             ` dan.j.williams
2026-03-05  1:51               ` Huang, Kai
2026-03-05  2:08                 ` dan.j.williams
2026-03-05  2:22                   ` Gregory Price
2026-03-05  3:01                     ` dan.j.williams
2026-03-05 10:24                       ` Huang, Kai
2026-03-05  8:11         ` Haifeng Xu
2026-03-05 10:25           ` Huang, Kai
2026-03-05 11:26             ` Haifeng Xu
2026-03-05  0:04     ` Huang, Kai
2026-03-05  0:44       ` Alison Schofield
2026-03-05  1:12         ` Huang, Kai

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