Re: [patch]VMSPLIT_2G conflicts with PAE

From: Jens Axboe
Date: Fri Dec 01 2006 - 02:56:18 EST


On Fri, Dec 01 2006, Shaohua Li wrote:
> PAGE_OFFSET is 0x78000000 with VMSPLIT_2G, this address is in the middle
> of the second pgd entry with pae enabled. This breaks assumptions
> (address is aligned to pgd entry's address) in a lot of places like
> pagetable_init. Fixing the assumptions is hard (eg, low mapping). SO I
> just changed the address to 0x80000000.
>
> Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
>
> diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
> index 8ff1c6f..fddfb26 100644
> --- a/arch/i386/Kconfig
> +++ b/arch/i386/Kconfig
> @@ -532,7 +532,7 @@ endchoice
> config PAGE_OFFSET
> hex
> default 0xB0000000 if VMSPLIT_3G_OPT
> - default 0x78000000 if VMSPLIT_2G
> + default 0x80000000 if VMSPLIT_2G
> default 0x40000000 if VMSPLIT_1G
> default 0xC0000000

0x78000000 was chosen since it gives you the full 2G as low memory, if
you mave it 0x80000000 then you still have a little highmem and need
that turned on.

--
Jens Axboe

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