numa: update Documentation/vm/numa, add memoryless node info

numa: update Documentation/vm/numa, add memoryless node info

Kamezawa Hiroyuki requested documentation for the numa_mem_id() and slab
related changes.  He suggested Documentation/vm/numa for this
documentation.  Looking at this file, it seems to me to be hopelessly out
of date relative to current Linux NUMA support.  At the risk of going down
a rathole, I have made an attempt to rewrite the doc at a slightly higher
level [I think] and provide pointers to other in-tree documents and
out-of-tree man pages that cover the details.

Let the games begin.

Signed-off-by: Lee Schermerhorn <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Eric Whitney <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: "Luck, Tony" <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>