Re: [PATCH] SPARSEMEM + NUMA can't handle unaligned memory regions?

[Dave Hansen <haveblue@us.ibm.com>]

On Tue, 2006-05-09 at 15:28 +0100, Andy Whitcroft wrote:		
> +/*
> + * During early boot we need to record the nid from which we will
> + * later allocate the section mem_map.  Encode this into the section
> + * pointer.  Overload the section_mem_map with this information.
> + */ 

Andy, this all looks pretty good.  Although, it might be nice to
document this a bit more. 

First, can you update the mem_section definition comment?  It has a nice
explanation of how we use section_mem_map, and it would be a shame to
miss this use.

Also, your comment says when we _record_ the nid information, but not
that it is only _used_ during early boot.  I think this is what Mike K.
missed, and it might be good to clarify.

How about something like this:

/*
 * During early boot, before section_mem_map is used for an actual
 * mem_map, we use section_mem_map to store the section's NUMA
 * node.  This keeps us from having to use another data structure.  The
 * node information is cleared just before we store the real mem_map.
 */

-- Dave