On Mon, Feb 01, 2021 at 11:13:14AM -0800, Dave Hansen wrote:
> Sure. Were you thinking of a code comment, or enhanced changelog?
>
> Let's say there's a system with two sockets each with the same three
> classes of memory: fast, medium and slow. Each memory class is placed
> in its own NUMA node and the CPUs are attached to the fast memory. That
> leaves 6 NUMA nodes (0-5):
>
> Socket A: 0, 1, 2
> Socket B: 3, 4, 5
>
> The migration path for this configuration path would start on the nodes
> with the processors and fast memory, progress through medium and end
> with the slow memory:
>
> 0 -> 1 -> 2 -> stop
> 3 -> 4 -> 5 -> stop
>
> This is represented in the node_demotion[] like this:
>
> { 1, // Node 0 migrates to 1
> 2, // Node 1 migrates to 2
> -1, // Node 2 does not migrate
> 4, // Node 3 migrates to 1
> 5, // Node 4 migrates to 2
> -1} // Node 5 does not migrate
>
> Is that what you were thinking of?
I would not mind to have the above explanation in a comment somewhere
in the code.
--
Oscar Salvador
SUSE L3
