Re: [PATCH 1/5] resources: add arch hook for preventing allocation in reserved areas

Jesse Barnes
2010-12-10T20:36:09Z

[Actually cc'ing Matthew this time]

On Fri, 10 Dec 2010 12:30:08 -0800
Jesse Barnes <jbarnes@virtuousgeek.org> wrote:

> On Wed, 08 Dec 2010 14:36:06 -0700
> Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:
>
> >
> > This adds arch_remove_reservations(), which an arch can implement if it
> > needs to protect part of the address space from allocation.
> >
> > Sometimes that can be done by just requesting a resource. This hook is to
> > cover cases where protected area doesn't fit well in the hierarchical
> > resource tree. For example, x86 BIOS E820 reservations are not related
> > to devices, so they may overlap part of, all of, or more than a device
> > resource.
> >
> > Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
> > ---
>
> Hm, this is bigger than the simple change of just avoiding the high 2M;
> Linus have you checked it out yet? It's nicer than simply adjusting
> PCIBIOS_MAX_MEM since it will affect all resource callers rather than
> just PCI, but it's definitely bigger.
>
> If you want just the simple change for 2.6.37 I can push that, but
> we'll need to get a tested-by from Matthew:
>
> diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
> index ca0437c..aef9f77 100644
> --- a/arch/x86/include/asm/pci.h
> +++ b/arch/x86/include/asm/pci.h
> @@ -141,7 +141,7 @@ void dma32_reserve_bootmem(void);
>
> /* generic pci stuff */
> #include <asm-generic/pci.h>
> -#define PCIBIOS_MAX_MEM_32 0xffffffff
> +#define PCIBIOS_MAX_MEM_32 0xfff00000
>
> #ifdef CONFIG_NUMA
> /* Returns the node based on pci bus */
>
> and I'll queue up this set for 2.6.38.
>
> Thanks,

--
Jesse Barnes, Intel Open Source Technology Center