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Subject: Re: [PATCH v4] Documentation, dt, numa: Add note to empty NUMA node
To:     Gavin Shan <gshan@redhat.com>, devicetree@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, robh+dt@kernel.org,
        drjones@redhat.com, shan.gavin@gmail.com
References: <20210625052338.4875-1-gshan@redhat.com>
From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <7cdbafb8-4c38-1aac-5362-25e27e1d13e4@infradead.org>
Date:   Thu, 24 Jun 2021 22:29:22 -0700
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On 6/24/21 10:23 PM, Gavin Shan wrote:
> The empty memory nodes, where no memory resides in, are allowed.
> For these empty memory nodes, the 'len' of 'reg' property is zero.
> The NUMA node IDs are still valid and parsed, but memory can be
> added to them through hotplug afterwards. I finds difficulty to
> get where it's properly documented.
> 
> So lets add note to empty memory nodes in the NUMA binding doc.
> 
> Signed-off-by: Gavin Shan <gshan@redhat.com>

Acked-by: Randy Dunlap <rdunlap@infradead.org>

Thanks.

> ---
>  Documentation/devicetree/bindings/numa.txt | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/numa.txt b/Documentation/devicetree/bindings/numa.txt
> index 21b35053ca5a..0fc882e44270 100644
> --- a/Documentation/devicetree/bindings/numa.txt
> +++ b/Documentation/devicetree/bindings/numa.txt
> @@ -109,6 +109,10 @@ Example:
>  Dual socket system consists of 2 boards connected through ccn bus and
>  each board having one socket/soc of 8 cpus, memory and pci bus.
>  
> +Note that empty memory nodes, which no memory resides in, are allowed.
> +The NUMA node IDs in these empty memory nodes are still valid, but
> +memory can be added into them through hotplug afterwards.
> +
>  	memory@c00000 {
>  		device_type = "memory";
>  		reg = <0x0 0xc00000 0x0 0x80000000>;
>