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

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Date:	Thu, 14 Jun 2007 17:21:16 -0400 (EDT)
From:	Justin Piszcz <jpiszcz@...idpixels.com>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>
cc:	Pim Zandbergen <P.Zandbergen@...roscoop.nl>,
	Andi Kleen <andi@...stfloor.org>, linux-kernel@...r.kernel.org,
	"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: [PATCH] trim memory not covered by WB MTRRs



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,
>>> Pim
>
> 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
>> buffers
>>
>> 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.
>
> Jesse
>

To Intel,

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

Justin.
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