Re: [PATCH] cheat for support of more than 256MB memory

[Ralf Baechle <ralf@linux-mips.org>]

On Wed, Jun 06, 2007 at 08:38:18AM +0200, Franck Bui-Huu wrote:

> >diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> >index 4975da0..62ef100 100644
> >--- a/arch/mips/kernel/setup.c
> >+++ b/arch/mips/kernel/setup.c
> >@@ -509,6 +509,14 @@ static void __init resource_init(void)
> >                res->end = end;
> >
> >                res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> >+#if defined(CONFIG_LEMOTE_FULONG) && defined(CONFIG_64BIT)
> >+               /* to keep memory continous, we tell system 0x10000000 - 
> >0x20000000 is reserved
> >+                * for memory, in fact it is io region, don't occupy it
> >+                *
> >+                * SPARSEMEM?
> 
> Definetly yes ! It has been designed for such issue and it should save
> you some memory.

A hole of 256MB size in the memory address map will cost 3.5MB with a 64-bit
kernel.  The other reason why I don't like this patch is that it drags
platform specific code into the generic MIPS code.

  Ralf