Hello,

On Tue, Jul 19, 2016 at 03:28:02PM +0800, Dou Liyang wrote:

In this series of patches, we are going to construct cpu <-> node mapping
for all possible cpus at boot time, which is a 1-1 mapping. It means the

1-1 mapping means that each cpu is mapped to its own private node
which isn't the case.  Just call it a persistent mapping?

Yes, each cpu is just in a persistent node.
However, the opposite is not true. 

I will modify it.

cpu will be mapped to the node it belongs to, and will never be changed.
If a node has only cpus but no memory, the cpus on it will be mapped to
a memory-less node. And the memory-less node should be onlined.

This patch allocate pgdats for all memory-less nodes and online them at
boot time. Then build zonelists for these nodes. As a result, when cpus
on these memory-less nodes try to allocate memory from local node, it
will automatically fall back to the proper zones in the zonelists.

Yeah, I think this is an a lot better approach for memory-less nodes.

Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>

Thanks,

Dou