Re: where to get ZONE_MOVABLE pathces?

[Mel Gorman <mel@csn.ul.ie>]

On Wed, 2007-10-17 at 15:06 +0800, Jacky(GuangXiang Lee) wrote:

> Can I precisely make the RAM range of a specific DIMM to be a independent
> zone?

Technically, yes as nothing stops you. Again, look at what
mm/page_alloc.c#free_area_init_nodes() does to setup each of the zones
as they currently exist.

Also, to reiterate, using a zone is easiest for a prototype but it's
unlikely to be the final solution. You probably want to use page
migration and a page-allocation callback from your driver to move pages
you detect are read-only to flash.

> e.x., I have a machine with 2G RAM(in place of 2 DIMM socket , each socket
> is plugged with 1G RAM)
> then I divided in kernel startup:
>  ZONE_DMA: 0~16M
> ZONE_DMA32: 16M~1G
> ZONE_READONLY:1G~2G (supposing this is my new created zone)
> hence the third zone corresponds to a DIMM hardware.
> right?
> 

You cannot assume that PFN ranges correspond to DIMMs in the normal
case. However, in your specific case where you have a piece of flash
that you want to use as a DIMM, you know exactly what the PFN ranges
are.

-- 
Mel Gorman

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