Re: [PATCH] x86_32: trim memory by updating e820 v3

[Jesse Barnes]

On Tuesday, April 29, 2008 3:37 am Ingo Molnar wrote:
> * Jesse Barnes <jesse.barnes@xxxxxxxxx> wrote:
> > > i think we should still try to make this a non-default option
> > > because modern Xorg should not have any need to touch MTRRs. Perhaps
> > > a .config dependent on CONFIG_DANGEROUS ;-)
> >
> > Well, not quite... we're still waiting on some way of getting WC
> > semantics for sysfs PCI files.  Suresh tells me something like that is
> > queued up, but until that hits the mainline X will still need to bang
> > the MTRRs to get decent performance.
>
> yes, the patch below is queued up for an eventual v2.6.26 merge. If it
> looks fine to you, could you please ack it so that we can send it to
> Linus? I'd like to do this after some pending PAT fixes are upstream.
>
> 	Ingo
>
> ---------------->
> Subject: x86, PAT: export resource_wc in pci sysfs
> From: venkatesh.pallipadi@xxxxxxxxx
> Date: Tue, 18 Mar 2008 17:00:22 -0700
>
> For the ranges with IORESOURCE_PREFETCH, export a new resource_wc interface
> in pci /sysfs along with resource (which is uncached).
>
> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
> Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>

I really would have preferred a new mmap flag for this like ia64 used to have, 
but Suresh and Venki tell me that a flag doesn't map very well to what some 
architectures support, so I suppose a new file is the way to go.  Should work 
fine for X's needs.

Acked-by:  Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>

Thanks,
Jesse
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