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

From: Jesse Barnes
Date: Mon Apr 28 2008 - 12:56:39 EST


On Monday, April 28, 2008 9:31 am Mika Fischer wrote:
> Jesse Barnes schrieb:
> > On Monday, April 28, 2008 6:53 am Ingo Molnar 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.
>
> Do you happen to know if this new sysfs-way will work correctly in the
> case where the MTRRs explicitly say that the video-memory is uncachable?

It should, since we'll be using PAT to set the cache control in the sysfs
case.

Jesse
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/