kernel/system can't see all 4G memory

[George R Goffe]

Hi,

My question is, am I missing something here?

I upgraded my lenovo 60t to 4G memory and don't seem to be able to see all 4G of the upgrade.

The hardware spec for this machine says it supports 4G memory.

Any hints/clues/tips would be GREATLY appreciated.

Thanks,

George...

uname says: 2.6.35.14-100.fc14.x86_64 #1 SMP Fri Oct 21 18:40:08 UTC 2011 x86_64 GNU/Linux

cat /proc/meminfo says:

MemTotal:        3090228 kB
MemFree:          531148 kB
Buffers:           66672 kB
Cached:           945684 kB
SwapCached:        58032 kB
Active:          1318288 kB
Inactive:         896312 kB
Active(anon):     915732 kB
Inactive(anon):   289888 kB
Active(file):     402556 kB
Inactive(file):   606424 kB
Unevictable:          68 kB
Mlocked:              68 kB
SwapTotal:       3145724 kB
SwapFree:        2751508 kB
Dirty:            143324 kB
Writeback:         15820 kB
AnonPages:       1183460 kB
Mapped:            76600 kB
Shmem:              3376 kB
Slab:             147820 kB
SReclaimable:      90724 kB
SUnreclaim:        57096 kB
KernelStack:        3600 kB
PageTables:        65096 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     4690836 kB
Committed_AS:    2884068 kB
VmallocTotal:   34359738367 kB
VmallocUsed:      113596 kB
VmallocChunk:   34359610520 kB
HardwareCorrupted:     0 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:     2843456 kB
DirectMap2M:      301056 kB

"It's not what you know that hurts you, It's what you know that ain't so." Wil Rogers... Wil would say, "STIFF THE FED"!!!

[Frank Elsner]

On Thu, 3 Nov 2011 00:46:15 -0700 (PDT) George R Goffe wrote:
> Hi,
>
> My question is, am I missing something here?
>
> I upgraded my lenovo 60t to 4G memory and don't seem to be able to see all 4G of the upgrade.
>
> The hardware spec for this machine says it supports 4G memory.
>
> Any hints/clues/tips would be GREATLY appreciated.

You should use the PAE version of the kernel.

--Frank Elsner

[Frank Murphy]

On 03/11/11 08:08, Frank Elsner wrote:
<snipped>
> > The hardware spec for this machine says it supports 4G memory.
> >
> > Any hints/clues/tips would be GREATLY appreciated.
>
> You should use the PAE version of the kernel.
>
> --Frank Elsner

He's on 64bit kernel-PAE is for 32bit.

[Frank Cox]

On Thu, 3 Nov 2011 00:46:15 -0700 (PDT)
George R Goffe wrote:
> I upgraded my lenovo 60t to 4G memory and don't seem to be able to see all 4G
> of the upgrade.

How much memory does your machine's bios screen tell you it has?

[George R Goffe]

Frank,

Thanks for your response.

The bios reports 4096MB.

George...

"It's not what you know that hurts you, It's what you know that ain't so." Wil Rogers... Wil would say, "STIFF THE FED"!!!

________________________________
From: Frank Cox 
To: [e-mail]
Cc: George R Goffe 
Sent: Thursday, November 3, 2011 1:16 AM
Subject: Re: kernel/system can't see all 4G memory

On Thu, 3 Nov 2011 00:46:15 -0700 (PDT)
George R Goffe wrote:
> I upgraded my lenovo 60t to 4G memory and don't seem to be able to see all 4G
> of the upgrade.

How much memory does your machine's bios screen tell you it has?

[DRSp.]

Am Donnerstag, den 03.11.2011, 00:46 -0700 schrieb George R Goffe:
> Hi,
>
> My question is, am I missing something here?
>
> I upgraded my lenovo 60t to 4G memory and don't seem to be able to see
> all 4G of the upgrade.
>
> The hardware spec for this machine says it supports 4G memory.
>
> Any hints/clues/tips would be GREATLY appreciated.
>
> Thanks,
>
> George...
>
> uname says: 2.6.35.14-100.fc14.x86_64 #1 SMP Fri Oct 21 18:40:08 UTC
> 2011 x86_64 GNU/Linux
>
> cat /proc/meminfo says:
>
> MemTotal:        3090228 kB
> MemFree:          531148 kB
> Buffers:           66672 kB
> Cached:           945684 kB
> SwapCached:        58032 kB
> Active:          1318288 kB
> Inactive:         896312 kB
> Active(anon):     915732 kB
> Inactive(anon):   289888 kB
> Active(file):     402556 kB
> Inactive(file):   606424 kB
> Unevictable:          68 kB
> Mlocked:              68 kB
> SwapTotal:       3145724 kB
> SwapFree:        2751508 kB
> Dirty:            143324 kB
> Writeback:         15820 kB
> AnonPages:       1183460 kB
> Mapped:            76600 kB
> Shmem:              3376 kB
> Slab:             147820 kB
> SReclaimable:      90724 kB
> SUnreclaim:        57096 kB
> KernelStack:        3600 kB
> PageTables:        65096 kB
> NFS_Unstable:          0 kB
> Bounce:                0 kB
> WritebackTmp:          0 kB
> CommitLimit:     4690836 kB
> Committed_AS:    2884068 kB
> VmallocTotal:   34359738367 kB
> VmallocUsed:      113596 kB
> VmallocChunk:   34359610520 kB
> HardwareCorrupted:     0 kB
> HugePages_Total:       0
> HugePages_Free:        0
> HugePages_Rsvd:        0
> HugePages_Surp:        0
> Hugepagesize:       2048 kB
> DirectMap4k:     2843456 kB
> DirectMap2M:      301056 kB
>
> "It's not what you know that hurts you, It's what you know that ain't
> so." Wil Rogers... Wil would say, "STIFF THE FED"!!!

shared grafic-card - perhaps? didn't google the specs of your
lenovo-t60...

[Roberto Ragusa]

On 11/03/2011 08:46 AM, George R Goffe wrote:
> Hi,
>
> My question is, am I missing something here?
>
> I upgraded my lenovo 60t to 4G memory and don't seem to be able to see all 4G of the upgrade.
>
> The hardware spec for this machine says it supports 4G memory.
>
> Any hints/clues/tips would be GREATLY appreciated.

x86_64, so something is happening at the hardware level (shared VGA?)
or BIOS level (wrong config, bugs).

What do you get with this command?

grep 'BIOS-e820' /var/log/dmesg

it will show how the memory areas have been described by the BIOS.

[Michael D. Setzer II]

On 3 Nov 2011 at 11:40, Roberto Ragusa wrote:

Date sent:      	Thu, 03 Nov 2011 11:40:44 +0100
From:           	Roberto Ragusa 
To:             	George R Goffe , 
    Community support for Fedora users 

Subject:        	Re: kernel/system can't see all 4G memory
Send reply to:  	Community support for Fedora users 

    

    
<mailto:[e-mail]?subject=subscribe
>
> On 11/03/2011 08:46 AM, George R Goffe wrote:
> > Hi,
> >
> > My question is, am I missing something here?
> >
> > I upgraded my lenovo 60t to 4G memory and don't seem to be able to
> > see all 4G of the upgrade.
> >
> > The hardware spec for this machine says it supports 4G memory.
> >
> > Any hints/clues/tips would be GREATLY appreciated.
>
> x86_64, so something is happening at the hardware level (shared VGA?)
> or BIOS level (wrong config, bugs).
>
> What do you get with this command?
>
> grep 'BIOS-e820' /var/log/dmesg
>
> it will show how the memory areas have been described by the BIOS.

Might be interesting to install memtest86+  and then run 
memtest-setup to add it as an option to grub.

Then restart the system, and select the memtest option.

Sometimes I've had to change the grub.conf lines for memtest, 
but don't recall what needed to be changed, but this is what I have 
in mine at the moment.

title Memtest86+ (4.20)
    root (hd0,0)
    kernel /memtest86+-4.20
> -- 
>    Roberto Ragusa    mail at robertoragusa.it
> -- 
> users mailing list
> [e-mail]
> To unsubscribe or change subscription options:
> https://admin.fedoraproject.org/mailman/listinfo/users
> Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines

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[George R Goffe]

Roberto,

I grasp the concept of reserved memory but do not understand what it's used for or what the ramifications are.

Memory reserved from 4g for the driver?

Hmmm. It looks like that last value at the bottom goes up to 4g. Is this the culprit?

I'm not doing anything special with graphics... that I know of.

Here's what I get from your command.

Regards,

George...

grep 'BIOS-e820' /var/log/dmesg
[    0.000000]  BIOS-e820: 0000000000000000 - 000000000009f000 (usable)
[    0.000000]  BIOS-e820: 000000000009f000 - 00000000000a0000 (reserved)
[    0.000000]  BIOS-e820: 00000000000d2000 - 00000000000d4000 (reserved)
[    0.000000]  BIOS-e820: 00000000000dc000 - 0000000000100000 (reserved)
[    0.000000]  BIOS-e820: 0000000000100000 - 00000000bfed0000 (usable)
[    0.000000]  BIOS-e820: 00000000bfed0000 - 00000000bfedf000 (ACPI data)
[    0.000000]  BIOS-e820: 00000000bfedf000 - 00000000bff00000 (ACPI NVS)
[    0.000000]  BIOS-e820: 00000000bff00000 - 00000000c0000000 (reserved)
[    0.000000]  BIOS-e820: 00000000f0000000 - 00000000f4000000 (reserved)
[    0.000000]  BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
[    0.000000]  BIOS-e820: 00000000fed00000 - 00000000fed00400 (reserved)
[    0.000000]  BIOS-e820: 00000000fed14000 - 00000000fed1a000 (reserved)
[    0.000000]  BIOS-e820: 00000000fed1c000 - 00000000fed90000 (reserved)
[    0.000000]  BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
[    0.000000]  BIOS-e820: 00000000ff800000 - 0000000100000000 (reserved)

"It's not what you know that hurts you, It's what you know that ain't so." Wil Rogers... Wil would say, "STIFF THE FED"!!!

________________________________
From: Roberto Ragusa 
To: George R Goffe ; Community support for Fedora users 
Sent: Thursday, November 3, 2011 3:40 AM
Subject: Re: kernel/system can't see all 4G memory

On 11/03/2011 08:46 AM, George R Goffe wrote:
> Hi,
>
> My question is, am I missing something here?
>
> I upgraded my lenovo 60t to 4G memory and don't seem to be able to see all 4G of the upgrade.
>
> The hardware spec for this machine says it supports 4G memory.
>
> Any hints/clues/tips would be GREATLY appreciated.

x86_64, so something is happening at the hardware level (shared VGA?)
or BIOS level (wrong config, bugs).

What do you get with this command?

grep 'BIOS-e820' /var/log/dmesg

it will show how the memory areas have been described by the BIOS.

[Lamar Owen]

On Nov 3, 2011, at 12:13 PM, George R Goffe wrote:
> grep 'BIOS-e820' /var/log/dmesg
> [    0.000000]  BIOS-e820: 0000000000000000 - 000000000009f000  
> (usable)

0009F000=636K; this is to the bottom of the UMB. ("640K should be  
enough for anyone")....
> [    0.000000]  BIOS-e820: 000000000009f000 - 00000000000a0000  
> (reserved)
> [    0.000000]  BIOS-e820: 00000000000d2000 - 00000000000d4000  
> (reserved)
> [    0.000000]  BIOS-e820: 00000000000dc000 - 0000000000100000  
> (reserved)

UMB/BIOS (Real mode) which is still 'reserved' in this x86_64 day....
> [    0.000000]  BIOS-e820: 0000000000100000 - 00000000bfed0000  
> (usable)

1MB and up to 3070MB, your 3GB of RAM.
> [    0.000000]  BIOS-e820: 00000000bfed0000 - 00000000bfedf000 (ACPI  
> data)
> [    0.000000]  BIOS-e820: 00000000bfedf000 - 00000000bff00000 (ACPI  
> NVS)
> [    0.000000]  BIOS-e820: 00000000bff00000 - 00000000c0000000  
> (reserved)
> [    0.000000]  BIOS-e820: 00000000f0000000 - 00000000f4000000  
> (reserved)
> [    0.000000]  BIOS-e820: 00000000fec00000 - 00000000fec10000  
> (reserved)
> [    0.000000]  BIOS-e820: 00000000fed00000 - 00000000fed00400  
> (reserved)
> [    0.000000]  BIOS-e820: 00000000fed14000 - 00000000fed1a000  
> (reserved)
> [    0.000000]  BIOS-e820: 00000000fed1c000 - 00000000fed90000  
> (reserved)
> [    0.000000]  BIOS-e820: 00000000fee00000 - 00000000fee01000  
> (reserved)
> [    0.000000]  BIOS-e820: 00000000ff800000 - 0000000100000000  
> (reserved)

PCI and PCI express mapping areas.  Your video (among other things)  
needs memory addresses; think of this as the 32-bit equivalent of the  
20-bit upper memory blocks.  In the case of 386 and up processors,  
hardware remapping of the reserved addresses was accomplished through  
virtual 8086 mode from 32-bit protect mode, and thus a 386 memory  
manager (QEMM, EMM386, etc) actually was a 32-bit 'kernel' that  
presented a single V86 'VM' and emulated real mode in that V86 VM, and  
set up the 386's MMU to map RAM into those holes.  Microsoft built  
upon this foundation the House of Windows/386, which morphed into the  
House of Windows 3.x (enhanced), which morphed into the House of Win9x/ 
ME.....

Many 386 motherboards from that era had '1MB' of RAM, but only 640K  
was usable without UMB mapping (and address line A20 'rollover' into  
the HMA, thanks to the segmented x86 architecture, for boards with  
more than 1MB).  The 32-bit boards have the same line, at 3GB, and for  
much the same reasons.

The BIOSs on Dells with 945 chipsets allow the ACPI business to move  
up, and thus frees up a few hundred MB of RAM address space.

The 965 chipset has hardware memory remapping, and can thus take the  
1GB of RAM 'lost' by the PCI hole and put it above the 4GB line, thus  
making the system need 33 bit or better hardware addressing (just  
because the CPU has more than 32-bit addressing doesn't mean those  
lines are connected to anything, after all.....)

[Lamar Owen]

On Nov 3, 2011, at 3:46 AM, George R Goffe wrote:
> I upgraded my lenovo 60t to 4G memory and don't seem to be able to  
> see all 4G of the upgrade.
>
> The hardware spec for this machine says it supports 4G memory.
>
> Any hints/clues/tips would be GREATLY appreciated.

It is a hardware limitation in the 945M chipset; the chipset  
physically only has 32 address lines, and the PCI/PCI-e memory map has  
to go somewhere.  That 'somewhere' is typically the top 1GB of address  
space, leaving 3GB (give or take) available for RAM.  If you don't  
have that 33rd address line, you can't go above the 32-bit barrier PAE  
or 64 bit regardless.

Same thing is true in my Dell Precision M65, although the Dell BIOS  
squeezes a little more out of it, 3.5GB or so is what I get with 4GB  
of RAM installed, and the 64-bit kernel, Fedora 14.

The 965 chipset fixes this by adding physical address lines to the  
chipset and adding remapping support in hardware.

In the Dell case, the Precision M65 is virtually the same machine as a  
Latitude D820; both have the 945; the Latitude D830 and equivalent  
Precision model have the 965, and can address all 4GB of RAM and can  
map the RAM that is displaced by the PCI/PCI-e address space above the  
4GB (32-bit) line. (If your BIOS has 'PCI Memory Hole Remapping'  
support you can try that; see http://en.wikipedia.org/wiki/PCI_hole  
for more information.  But this won't help go above the 32-bit  
addressing barrier if the chipset physically only has 32-bits of  
addressing capacity, regardless of processor installed.

Again, neither PAE nor 64-bit OS will help since the 945 chipset  
physically does not have a 33rd (and above) address line, so the PCI/ 
PCI-e memory map has to go somewhere in the 4GB (32-bit) address  
space, taking away from the 4GB of installed RAM.

Please also see http://www.dansdata.com/askdan00015.htm

and

http://www.linuxquestions.org/questions/linux-hardware-18/intel-945-chipset-...