[gentoo-user] Only 4 of 8 GB usable

[gentoo-user] Only 4 of 8 GB usable

[Alex Schuster]

Hi there!

So I installed another 4 GiB RAM into a Gentoo amd64 system that had 4 GiB
already. But it still sees only 4 GiB, not 8 GiB:

leela ~ # uname -a
Linux leela 3.6.11-gentoo #3 SMP Mon Feb 4 15:37:48 CET 2013 x86_64 AMD
A6-3500 APU with Radeon(tm) HD Graphics AuthenticAMD GNU/Linux 

leela ~ #
free -m total       used       free     shared    buffers     cached
Mem:          3688       3269        419          0        108       1050
-/+ buffers/cache:       2110       1577
Swap:         2047         54       1993

Huh? Any idea why this is? The BIOS shows the full 8GiB, and lshw finds
it. dmidecode shows that 8G should work:

leela ~ # dmidecode -t 16
# dmidecode 2.11
SMBIOS 2.7 present.

Handle 0x0008, DMI type 16, 23 bytes
Physical Memory Array
        Location: System Board Or Motherboard
        Use: System Memory
        Error Correction Type: None
        Maximum Capacity: 8 GB
        Error Information Handle: Not Provided
        Number Of Devices: 2

In case this helps, I uploaded the outputs of dmesg [1], lshw -c memory
[2] and full dmidecode output [3]. The dmesg output is somewhat weird
though, it has several 'vmalloc: allocation failure: 0 bytes' entries. I
suspected those were causing the problem, but I found that I needed to
activate CONFIG_KALLSYMS=y, and they are gone. But still only 4 GiB RAM.
The system is using an old kernel right now, so I cannot get the current
dmesg, sorry for this.

Probably related: Since I inserted this 2nd RAM module, wakeup
from hibernate-ram does no longer work.

Does this ring any bells? I'm out of ideas. Except than pulling out the 4
GB, or trying another mainboard.

[1] http://www.wonkology.org/tmp/lshw.txt
[2] http://www.wonkology.org/tmp/dmesg.txt
[3] http://www.wonkology.org/tmp/dmidecode.txt

	Wonko

Re: [gentoo-user] Only 4 of 8 GB usable

[wraeth]

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On 22/05/14 07:37, Alex Schuster wrote:
> Does this ring any bells? I'm out of ideas. Except than pulling out the 4 
> GB, or trying another mainboard.

Just a quick suggestion to help rule it out: try booting a LiveCD or other
"one-size-fits-most" medium and seeing if your full memory is registering
there. If it is, then it's not a hardware malfunction; if it doesn't, then
either you've got bad hardware or a configuration issue in your BIOS.

cheers
wraeth
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Re: [gentoo-user] Only 4 of 8 GB usable

[Dale]

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wraeth wrote:
>
>
> On 22/05/14 07:37, Alex Schuster wrote:
> > Does this ring any bells? I'm out of ideas. Except than pulling out
the 4
> > GB, or trying another mainboard.
>
> Just a quick suggestion to help rule it out: try booting a LiveCD or other
> "one-size-fits-most" medium and seeing if your full memory is registering
> there. If it is, then it's not a hardware malfunction; if it doesn't, then
> either you've got bad hardware or a configuration issue in your BIOS.
>
> cheers
> wraeth


Isn't there a kernel setting that cuts off after 4GBs or something?  I
seem to recall having to turn that on at some point.  I would think this
would be on by default but . . . .

Dale

:-)  :-)

-- 
I am only responsible for what I said ... Not for what you understood or
how you interpreted my words!


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Re: [gentoo-user] Only 4 of 8 GB usable

[covici]

Dale <rdalek1967@gmail.com> wrote:

> wraeth wrote:
> >
> >
> > On 22/05/14 07:37, Alex Schuster wrote:
> > > Does this ring any bells? I'm out of ideas. Except than pulling out
> the 4
> > > GB, or trying another mainboard.
> >
> > Just a quick suggestion to help rule it out: try booting a LiveCD or other
> > "one-size-fits-most" medium and seeing if your full memory is registering
> > there. If it is, then it's not a hardware malfunction; if it doesn't, then
> > either you've got bad hardware or a configuration issue in your BIOS.
> >
> > cheers
> > wraeth
> 
> 
> Isn't there a kernel setting that cuts off after 4GBs or something?  I
> seem to recall having to turn that on at some point.  I would think this
> would be on by default but . . . .

Make sure you are really running a 64-bit kernel!  Sure seems like you
are not to me, but there may be other things.


-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici
         covici@ccs.covici.com

Re: [gentoo-user] Only 4 of 8 GB usable

[Neil Bothwick]

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On Wed, 21 May 2014 20:38:15 -0500, Dale wrote:

> Isn't there a kernel setting that cuts off after 4GBs or something?  I
> seem to recall having to turn that on at some point.  I would think this
> would be on by default but . . . .

That's only in 32 bit kernels AFAIR. The live CD idea is a good one, also
run memtest86+ to make sure the RAM is not only seen but working.


-- 
Neil Bothwick

I have seen things you lusers would not believe.
I've seen Sun monitors on fire off the side of the multimedia lab.
I've seen NTU lights glitter in the dark near the Mail Gate.
All these things will be lost in time, like the root partition last week.
Time to die.

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Re: [gentoo-user] Only 4 of 8 GB usable

[Dale]

Neil Bothwick wrote:
> On Wed, 21 May 2014 20:38:15 -0500, Dale wrote:
>
>> Isn't there a kernel setting that cuts off after 4GBs or something?  I
>> seem to recall having to turn that on at some point.  I would think this
>> would be on by default but . . . .
> That's only in 32 bit kernels AFAIR. The live CD idea is a good one, also
> run memtest86+ to make sure the RAM is not only seen but working.
>
>


Could be.  I can't recall if it was on my new rig or my older rig that I
had to do that on.  Old age and got to much stuff going on. 

Dale

:-)  :-) 

-- 
I am only responsible for what I said ... Not for what you understood or how you interpreted my words!

Re: [gentoo-user] Only 4 of 8 GB usable

[wraeth]

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On 22/05/14 09:20, wraeth wrote:
> Just a quick suggestion to help rule it out: try booting a LiveCD or other 
> "one-size-fits-most" medium and seeing if your full memory is registering 
> there. If it is, then it's not a hardware malfunction; if it doesn't, then 
> either you've got bad hardware or a configuration issue in your BIOS.

Just had another thought, too: you could check what the BIOS reports either by
entering the BIOS configuration and going to the system information area, or
by inspecting your machines POST output (the diagnostic information that is
displayed during boot, sometimes hidden by a splash screen with "Press
[something] to show details".

cheers
wraeth
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Re: [gentoo-user] Only 4 of 8 GB usable

[Daniel Troeder]

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Am 21.05.2014 23:37, schrieb Alex Schuster:
> Hi there!
> 
> So I installed another 4 GiB RAM into a Gentoo amd64 system that had 4 GiB
> already. But it still sees only 4 GiB, not 8 GiB:
> 
> leela ~ # uname -a
> Linux leela 3.6.11-gentoo #3 SMP Mon Feb 4 15:37:48 CET 2013 x86_64 AMD
> A6-3500 APU with Radeon(tm) HD Graphics AuthenticAMD GNU/Linux 
> 
> leela ~ #
> free -m total       used       free     shared    buffers     cached
> Mem:          3688       3269        419          0        108       1050
> -/+ buffers/cache:       2110       1577
> Swap:         2047         54       1993
> 
> Huh? Any idea why this is? The BIOS shows the full 8GiB, and lshw finds
> it. dmidecode shows that 8G should work:
> 
> leela ~ # dmidecode -t 16
> # dmidecode 2.11
> SMBIOS 2.7 present.
> 
> Handle 0x0008, DMI type 16, 23 bytes
> Physical Memory Array
>         Location: System Board Or Motherboard
>         Use: System Memory
>         Error Correction Type: None
>         Maximum Capacity: 8 GB
>         Error Information Handle: Not Provided
>         Number Of Devices: 2
> 
> In case this helps, I uploaded the outputs of dmesg [1], lshw -c memory
> [2] and full dmidecode output [3]. The dmesg output is somewhat weird
> though, it has several 'vmalloc: allocation failure: 0 bytes' entries. I
> suspected those were causing the problem, but I found that I needed to
> activate CONFIG_KALLSYMS=y, and they are gone. But still only 4 GiB RAM.
> The system is using an old kernel right now, so I cannot get the current
> dmesg, sorry for this.
> 
> Probably related: Since I inserted this 2nd RAM module, wakeup
> from hibernate-ram does no longer work.
> 
> Does this ring any bells? I'm out of ideas. Except than pulling out the 4
> GB, or trying another mainboard.
> 
> [1] http://www.wonkology.org/tmp/lshw.txt
> [2] http://www.wonkology.org/tmp/dmesg.txt
> [3] http://www.wonkology.org/tmp/dmidecode.txt
> 
> 	Wonko
> 
To be sure, that the new RAM isn't broken, try booting with only the new
RAM inserted in the 1st slot. If it works, insert the old RAM into the
2nd slot and see if the problem persists.

Good luck
Daniel


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[gentoo-user] Re: Only 4 of 8 GB usable

[Nikos Chantziaras]

On 22/05/14 00:37, Alex Schuster wrote:
> So I installed another 4 GiB RAM into a Gentoo amd64 system that had 4 GiB
> already. But it still sees only 4 GiB, not 8 GiB:
>
> leela ~ # uname -a
> Linux leela 3.6.11-gentoo #3 SMP Mon Feb 4 15:37:48 CET 2013 x86_64 AMD
> A6-3500 APU with Radeon(tm) HD Graphics AuthenticAMD GNU/Linux

Emerge sys-apps/memtest86+ and boot it (it should create a Grub entry). 
How much memory does it see/test?

Are there any memory settings in your BIOS? (Possibly related to GPU 
memory.)

Re: [gentoo-user] Re: Only 4 of 8 GB usable

[ny6p01]

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On Mon, May 26, 2014 at 08:07:52AM +0300, Nikos Chantziaras wrote:
> On 22/05/14 00:37, Alex Schuster wrote:
> > So I installed another 4 GiB RAM into a Gentoo amd64 system that had 4 GiB
> > already. But it still sees only 4 GiB, not 8 GiB:
> >
> > leela ~ # uname -a
> > Linux leela 3.6.11-gentoo #3 SMP Mon Feb 4 15:37:48 CET 2013 x86_64 AMD
> > A6-3500 APU with Radeon(tm) HD Graphics AuthenticAMD GNU/Linux
> 
> Emerge sys-apps/memtest86+ and boot it (it should create a Grub entry). 
> How much memory does it see/test?
> 
> Are there any memory settings in your BIOS? (Possibly related to GPU 
> memory.)
> 
> 

Also, check how the mem card is seated. Remove, and reseat. Mem cards are
known to be very picky about how they are seated in their slots.  Also, it's
not all that uncommon for a particular mem chip (esp.  one purchased used)
to be defective. HTH.

Lee

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[gentoo-user] Re: Only 4 of 8 GB usable

[Kai Krakow]

Alex Schuster <wonko@wonkology.org> schrieb:

> So I installed another 4 GiB RAM into a Gentoo amd64 system that had 4 GiB
> already. But it still sees only 4 GiB, not 8 GiB:
> 
> leela ~ # uname -a
> Linux leela 3.6.11-gentoo #3 SMP Mon Feb 4 15:37:48 CET 2013 x86_64 AMD
> A6-3500 APU with Radeon(tm) HD Graphics AuthenticAMD GNU/Linux
> 
> leela ~ #
> free -m total       used       free     shared    buffers     cached
> Mem:          3688       3269        419          0        108       1050
> -/+ buffers/cache:       2110       1577
> Swap:         2047         54       1993
> 
> Huh? Any idea why this is? The BIOS shows the full 8GiB, and lshw finds
> it. dmidecode shows that 8G should work:

Two ideas:

An addon card is blocking the usage of RAM above 4 GB. See if your BIOS is 
enabled for 64 bit systems and if everything will map above 32 bit address 
space. Usually there are BIOS configuration sections like "resource 
allocation", "memory hole", "resource relocation", or similar - you get the 
idea.

My second idea is: Look at dmesg if there are errors from MTRR which allow 
the kernel to only make use of 4 GB of RAM. Usually, the kernel tries its 
best to adjust MTRR to make as much use of RAM as possible with lower 
priority to memory access performance. If you tuned MTRR manually before, 
you are likely to be running into memory issues. Also, check if there is a 
BIOS update available. Sometimes this is needed to correct MTRR settings so 
memory becomes avaiable to the OS. Also look at your kernel options 
regarding MTRR support / defaults.

These kernel options may help you: mtrr_gran_size, mtrr_chunk_size

E.g., I have 16 GB installed and adjusted MTRR settings to allow using write 
combining (which cannot be enabled by the kernel with the default MTRR 
settings from BIOS). But that came with the downside of loosing around 1 GB 
of usable RAM.

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