Re: [PATCH] trim memory not covered by WB MTRRs

From: Justin Piszcz
Date: Thu Jun 14 2007 - 17:21:42 EST

On Thu, 14 Jun 2007, Jesse Barnes wrote:

On Thursday, June 14, 2007 1:26:07 Justin Piszcz wrote:
On Thu, 14 Jun 2007, Pim Zandbergen wrote:
Thanks for this patch. I was having the exact same symptoms as
Justin Piszcz, on a different, but similar motherboard:

Motherboard: GigaByte GA-G33-DS3R
BIOS rev: F2
Chipset: Intel G33
Memory: 8GB
Distro: Fedora 7 x86_64
Kernel: kernel-2.6.21-1.3194.fc7

Building vanilla 2.6.22-rc4 with your patch solved the problem.

I'm now seeing this in the syslog

**** WARNING: likely BIOS bug
**** MTRRs don't cover all of memory, trimmed 196608 pages

leaving me 7416672 kB of usable memory.

If there's any way I can help with more info or testing,
then let me know.


Thanks for testing, Pim. Glad it works for you. Keep an eye out for
BIOS upgrades, the next version might fix it.

That's strange, I guess different chipsets 'chew' up different
amounts of memory OR you have your DVT(?) (video-card
memory/aperature) set to 256MB? I have mine set to 128MB, in top:

Mem: 8039576k total, 6187304k used, 1852272k free, 696k

What type of memory are you using and what is your DVT set to?

Different BIOSes will map things differently, so I'd expect differences
in the "trimmmed xxx pages" message across machines. But yeah, BIOS
config options can also affect things, in particular I've heard that
the fan control options change MTRR setup significantly.


To Intel,

When will HECI be supported via the kernel? When it becomes supported, would that alter the MTRR map at all?

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