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

From: Dave Hansen
Date: Tue May 09 2006 - 12:27:31 EST


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

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