Re: [patch] srat, x86_64: Add support for nodes spanning other nodes

[Chris Snook <csnook@redhat.com>]

Suresh Siddha wrote:
> For example, If the physical address layout on a two node system with 8 GB
> memory is something like:
> node 0: 0-2GB, 4-6GB
> node 1: 2-4GB, 6-8GB
> 
> Current kernels fail to boot/detect this NUMA topology.
> 
> ACPI SRAT tables can expose such a topology which needs to be supported.
> 
> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
> ---
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 227fdb0..99eb102 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -880,6 +880,15 @@ config X86_64_ACPI_NUMA
>  	help
>  	  Enable ACPI SRAT based node topology detection.
>  
> +# Some NUMA nodes have memory ranges that span
> +# other nodes.  Even though a pfn is valid and
> +# between a node's start and end pfns, it may not
> +# reside on that node.  See memmap_init_zone()
> +# for details.
> +config NODES_SPAN_OTHER_NODES
> +	def_bool y
> +	depends on X86_64_ACPI_NUMA
> +

Is this hunk a leftover from your testing?  You're not using the config option 
anywhere, and there isn't really anything in this patch that would justify 
making this a separate config option in mainline.

-- Chris