Re: Discontinuous memory!!

On Tue, Oct 30, 2001 at 06:11:43PM +0800, Green wrote:

I am porting Linux to R3912. 

There are two memory block on my target board. 

One is 16MB                  from 0x8000 0000 to 0x8100 0000.

The other one is 16MB   from 0x8200 0000 to 0x8300 0000.

But I found kernel just managed the first memory block.

How could I modify the kernel to support 32MB discontinuous memory?

Now I am trying to add entries to page table.
It will halt at decompressing ramdisk.

Has anyone resolve this kind of problem before?

The kernel support this type of memory architecture if you enable
CONFIG_DISCONTIGMEM.  One machine which uses this feature is the Origin,
grep in arch/mips64 for CONFIG_DISCONTIGMEM.  There are also several
ARM system using it.

As support for CONFIG_DISCONTIGMEM is less than perfect you should check
if your system allows for reconfiguration of memory as a single physically
contiguous chunk.

Don't use add_memory_region() in this case; that code only works well
for small holes in memory address space.  Your holes are fairly large
so memory management would waste about 2mb if you would not use
CONFIG_DISCONTIGMEM.

  Ralf