Re: [PATCH v8 1/7] x86, memhp, numa: Online memory-less nodes at boot time.

Dou Liyang <douly.fnst@xxxxxxxxxxxxxx> · Wed, 20 Jul 2016 09:52:56 +0800

    在 2016年07月20日 02:50, Tejun Heo 写道:

      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@xxxxxxxxxxxxxx>

    Thanks,

Dou