Re: Sparsemem on ep93xx

[Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx>]

On Tue, Nov 25, 2008 at 09:13:17AM +0100, Marco Stornelli wrote:
> Hi Russell,
> 
> thank you very much for your response. Only some comments about your
> response:
> 
> Yes, I agree, but (at least in 2.6.27.7) the file
> arm/include/asm/sparsemem.h is:
> 
> #ifndef ASMARM_SPARSEMEM_H
> #define ASMARM_SPARSEMEM_H
> 
> #include <asm/memory.h>
> 
> #define MAX_PHYSADDR_BITS	32
> #define MAX_PHYSMEM_BITS	32
> #define SECTION_SIZE_BITS	NODE_MEM_SIZE_BITS
> 
> #endif
> 
> It includes asm/memory.h that includes the memory.h in the mach folder.
> So if I want to modify *only* the memory.h in the mach folder, I have to
> use NODE_MEM_SIZE_BITS to assign the right value (24 in my case as you
> said) to SECTION_SIZE_BITS.

That means that the kernel version you're looking at is too old and
doesn't support sparsemem properly on ARM.  Looking at the git history,
it was merged in the post 2.6.27 merge window, so 2.6.28 will be the
first kernel which correctly supports sparsemem.

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