linux-kernel - Re: [PATCH 2/2] x86: mtrr_cleanup try gran

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Message-ID: <20081003012036.28c00fd7@werewolf.home>
Date:	Fri, 3 Oct 2008 01:20:36 +0200
From:	"J.A. Magallón" <jamagallon@....com>
To:	Linux-Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] x86: mtrr_cleanup try gran_size to less than 1M

On Thu, 2 Oct 2008 15:39:34 -0700, "Yinghai Lu" <yinghai@...nel.org> wrote:

> On Thu, Oct 2, 2008 at 3:32 PM, J.A. Magallón <jamagallon@....com> wrote:
> > On Mon, 29 Sep 2008 18:54:12 -0700, Yinghai Lu <yhlu.kernel@...il.com> wrote:
> >
> > Also, on a 64 bit box with 4Gb, it gives this:
> >
> > cicely:~# cat /proc/mtrr
> > reg00: base=0x00000000 (   0MB), size=4096MB: write-back, count=1
> > reg01: base=0x100000000 (4096MB), size=1024MB: write-back, count=1
> > reg02: base=0x140000000 (5120MB), size= 512MB: write-back, count=1
> > reg03: base=0x160000000 (5632MB), size= 256MB: write-back, count=1
> > reg04: base=0x80000000 (2048MB), size=2048MB: uncachable, count=1
> >
> boundary handling may have problem...
> 
> should have
> > reg00: base=0x00000000 (   0MB), size=2048MB: write-back, count=1

should not this                           ^^^^^  be 4096MB ??

> > reg01: base=0x100000000 (4096MB), size=1024MB: write-back, count=1
> > reg02: base=0x140000000 (5120MB), size= 512MB: write-back, count=1
> > reg03: base=0x160000000 (5632MB), size= 256MB: write-back, count=1
> 
> can you post /proc/mtrr with disable_mtrr_cleanup?
> 

Oops, sorry, this is without cleanup. This is a distro kernel and is built
but not enable by deafult. As it is rc7, I will use 'enble_mtrr_cleanup' ;):

cicely:~# cat /proc/mtrr
reg00: base=0x00000000 (   0MB), size=2048MB: write-back, count=1
reg01: base=0x100000000 (4096MB), size=1024MB: write-back, count=1
reg02: base=0x140000000 (5120MB), size= 512MB: write-back, count=1
reg03: base=0x160000000 (5632MB), size= 256MB: write-back, count=1

I have lost 2Gb ?

cicely:~# free
             total       used       free     shared    buffers     cached
Mem:       3755568     182348    3573220          0      14024      72716
-/+ buffers/cache:      95608    3659960

I can't easily try your patch, this is a distro kernel.
I will get the src.rpm...

Ahhhhh....

This is a dual opteron board. dmidecode says:

Handle 0x0026, DMI type 16, 15 bytes
Physical Memory Array
    Location: System Board Or Motherboard
    Use: System Memory
    Error Correction Type: Single-bit ECC
    Maximum Capacity: 8 GB
    Error Information Handle: Not Provided
    Number Of Devices: 8

So it maps one Opteron memory in first 4Gb and the other on the second 4Gb.
So I should have 2Gb@0 and 2Gb@....
What I don't know is why the bios eats up 256Mb.

-- 
J.A. Magallon <jamagallon()ono!com>     \               Software is like sex:
                                         \         It's better when it's free
Mandriva Linux release 2009.0 (Cooker) for i586
Linux 2.6.25-jam18 (gcc 4.3.1 20080626 (GCC) #1 SMP
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