Re: [PATCH 2/2] powerpc/hotplug: Ensure nodes initialized for hotplug

[Michael Bringmann <mwb@linux.vnet.ibm.com>]

>>>
>>>> +	if ((NODE_DATA(nid) == NULL) ||
>>>> +	    (NODE_DATA(nid)->node_spanned_pages == 0)) {
>>>> +		if (try_online_node(nid))
>>>
>>> .. to do something like online a node.
>>
>> We have changed the function name to 'find_cpu_nid'.
> 
> Ok, but I would still not expect 'find_cpu_nid' to online the node.
> 

We would have to talk to the developer that created try_online_node()
which fully initializes the node and all of the related data structures.
A few of the APIs are external, and 'numa.c' knows how to allocate the
base 'pgdat' structure, but everything else that the kernel depends
upon for a node is handled in mm/page_alloc.c and mm/hotplug_memory.c.
I was trying to avoid piecemeal changes to that code -- avoid any changes
if it comes to it.

Even if it was not expected to put the node online, it is convenient,
as otherwise the patches to 'numa.c' would have to put the node online
-- that is expected for a CPU that is online.

Regards,

-- 
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line  363-5196
External: (512) 286-5196
Cell:       (512) 466-0650
mwb@linux.vnet.ibm.com