Re: [PATCH] ppc32: fix CONFIG_TASK_SIZE handling on 44x

[Kumar Gala <kumar.gala@freescale.com>]

On May 18, 2005, at 9:14 AM, Dan Malek wrote:

>
>
> On May 18, 2005, at 6:21 AM, Eugene Surovegin wrote:
>
> > This patch fixed CONFIG_TASK_SIZE handling on 44x.
>
> Paul suggested to me and I've been contemplating changing
>  the page table management on PowerPC to something similar
>  to other platforms.=A0 At first, I was only going to do this on 8xx,
>  but I think I'll do it for PowerPC in general so all boards can
>  take advantage if they choose to do so.
>
> Other ports populate the user page tables with the kernel pmd
>  entries upon kernel faults, then we don't have to distinguish
>  among page tables during the TLB exceptions.=A0 I'm hoping we
>  can populate the init page table entries at boot time, and then
>  everyone will inherit them, eliminating all faults unless the kernel
>  vmalloc space grows to need a new pmd entry.

I'm a bit concerned about this in the future.  On Book-E parts we may=20
end up actually utilizing the address space bit to provide a true 4G/4G=20=

split.  I understand the current pain in doing this today.  I just want=20=

you to be aware of what the future might bring.

>  This would be a generic solution to selecting task size, among
>  other advanced memory mapping options.
>
> I'll keep you posted.

While we wait on this I think getting Eugene's patch is worth while.

- kumar