| View previous topic :: View next topic |
| Author |
Message |
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
 Posted: Tue Nov 25, 2008 7:45 pm Post subject: Only seeing 3 out of 4GB on AMD64 system [SOLVED] |
 |
|
I just installed 4GB of RAM into my laptop, and the BIOS reports that I have 4GB, but if I run 'free', I see:
| Code: |
total used free shared buffers cached
Mem: 3019152 1384620 1634532 0 203372 536308
-/+ buffers/cache: 644940 2374212
Swap: 1048568 0 1048568
|
I've done a bit of research, and apparently there is no "high memory" option in 64 bit kernels, and that this usually boils down to a BIOS "memory hole" issue, however my BIOS does not allow me to configure any memory settings (or much of anything at all).
I'm going to try a few 64bit livecds of various distros to see if all of them have the same issue.
In the meantime, does anyone here have a suggestion?
Thanks.
_________________
Vermont Free PC
http://www.vtfreepc.org
Last edited by rev138 on Thu Jan 15, 2009 10:17 pm; edited 1 time in total |
|
| Back to top |
|
 |
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Tue Nov 25, 2008 8:16 pm Post subject: |
|
|
No luck with a CentOS 5 x86_64 CD. Same memory limit.
Back in gentoo, I see this in my dmesg output:
| Code: |
system 00:05: iomem range 0xfed00000-0xfed003ff could not be reserved
system 00:07: ioport range 0x480-0x48f has been reserved
system 00:07: ioport range 0xffff-0xffff has been reserved
system 00:07: ioport range 0xffff-0xffff has been reserved
system 00:07: ioport range 0x400-0x47f has been reserved
system 00:07: ioport range 0x1180-0x11ff has been reserved
system 00:07: ioport range 0xfe00-0xfe00 has been reserved
system 00:07: iomem range 0xff800000-0xff800fff could not be reserved
system 00:09: iomem range 0xfed1c000-0xfed1ffff could not be reserved
system 00:09: iomem range 0xfed10000-0xfed13fff could not be reserved
system 00:09: iomem range 0xfed18000-0xfed18fff could not be reserved
system 00:09: iomem range 0xfed19000-0xfed19fff could not be reserved
system 00:09: iomem range 0xe0000000-0xefffffff could not be reserved
system 00:09: iomem range 0xfed20000-0xfed3ffff could not be reserved
|
That seems relevant...
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
DaggyStyle
Watchman
Joined: 22 Mar 2006
Posts: 5916
|
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 2:50 am Post subject: |
|
|
Yeah. Saw that thread already.
Unless I missed something, the OP is only missing 128MB, not a whole gig.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
dmpogo
Advocate
Joined: 02 Sep 2004
Posts: 3286
Location: Canada
|
| Posted: Wed Nov 26, 2008 3:06 am Post subject: |
|
|
Your gig does not sound right. The memory hole that one deals with is usually 700 Mb. As well, as you have found, with proper BIOS, if this
memory hole is not needed, it can be remapped and reused, resulting in the loss of ~130 Mb.
On my 8 and 32 Gb opteron, where I found the issue first, the memory hole is that 700 Gb.
1)
BTW, on boot, if you enable memory scan in BIOS (disable fast boot or whatever), how much RAM does it show ? Memory hole is typically seen
during the scan (i.e it pauses on a boundary).
2) If it does scans to 4Gb, see what memory model your kernel options give, perhaps you have a choice (there can be flat, sparse, discontinous).
But it does look like 1Gb is not recongnized. |
|
| Back to top |
|
|
dmpogo
Advocate
Joined: 02 Sep 2004
Posts: 3286
Location: Canada
|
| Posted: Wed Nov 26, 2008 3:12 am Post subject: |
|
|
| BTW, how do your 4Gb look like ? Two sticks of 2Gb ? |
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 3:55 am Post subject: |
|
|
Yes. 2x2GB DDR2.
I have some new info. I was using gentoo-sources-2.6.27-r2, but I updated to -r3, and now 'free' is showing more memory than it did under the old kernel.
| Code: |
total used free shared buffers cached
Mem: 3025008 1495268 1529740 0 80744 1112568
-/+ buffers/cache: 301956 2723052
Swap: 1048568 0 1048568
|
This makes me think that perhaps it's still a kernel issue and not the BIOS.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 3:59 am Post subject: |
|
|
| dmpogo wrote: | 1) BTW, on boot, if you enable memory scan in BIOS (disable fast boot or whatever), how much RAM does it show ? Memory hole is typically seen
during the scan (i.e it pauses on a boundary). |
I'll check on that.
| dmpogo wrote: | | 2) If it does scans to 4Gb, see what memory model your kernel options give, perhaps you have a choice (there can be flat, sparse, discontinous). |
"Sparse" is the only choice available.
Thanks for the help so far.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
dmpogo
Advocate
Joined: 02 Sep 2004
Posts: 3286
Location: Canada
|
| Posted: Wed Nov 26, 2008 4:08 am Post subject: |
|
|
| rev138 wrote: | Yes. 2x2GB DDR2.
I have some new info. I was using gentoo-sources-2.6.27-r2, but I updated to -r3, and now 'free' is showing more memory than it did under the old kernel.
| Code: |
total used free shared buffers cached
Mem: 3025008 1495268 1529740 0 80744 1112568
-/+ buffers/cache: 301956 2723052
Swap: 1048568 0 1048568
|
This makes me think that perhaps it's still a kernel issue and not the BIOS. |
free is not important, it depends on current load (and kernel size, since kernel occupies some memory). Only important is 'total'
Could you try to reset the chips ? (although with 2Gb I would be suprised that 1Gb not registers).
Also, go to manufacturer website and look at BIOS upgrade. I have hard time to believe it has no memory related options while providing
possibility to have 4Gb. I suspect BIOS is just unable to handle > 3Gb. |
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 4:09 am Post subject: |
|
|
I turned off "quiet boot" but it doesn not do any actual memory count. It just flashes the POST screen for about 0.5 seconds. This BIOS sucks.
In any case, after ctrl-alt-del'ing about 6 times I was able to make out that it shows "4030MB" on the POST screen.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 4:11 am Post subject: |
|
|
| dmpogo wrote: | | free is not important, it depends on current load (and kernel size, since kernel occupies some memory). Only important is 'total' |
I was posting output from the command "free". The total memory is now slightly higher, if you check it against my original post.
| dmpogo wrote: | | Could you try to reset the chips ? (although with 2Gb I would be suprised that 1Gb not registers). |
I could, but I really doubt that's the problem. The BIOS thinks I have 4GB.
| dmpogo wrote: | | Also, go to manufacturer website and look at BIOS upgrade. I have hard time to believe it has no memory related options while providing possibility to have 4Gb. I suspect BIOS is just unable to handle > 3Gb. |
Tried that one too. No BIOS update available for download.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
dmpogo
Advocate
Joined: 02 Sep 2004
Posts: 3286
Location: Canada
|
| Posted: Wed Nov 26, 2008 4:24 am Post subject: |
|
|
| rev138 wrote: | | dmpogo wrote: | | free is not important, it depends on current load (and kernel size, since kernel occupies some memory). Only important is 'total' |
I was posting output from the command "free". The total memory is now slightly higher, if you check it against my original post.
| dmpogo wrote: | | Could you try to reset the chips ? (although with 2Gb I would be suprised that 1Gb not registers). |
I could, but I really doubt that's the problem. The BIOS thinks I have 4GB.
| dmpogo wrote: | | Also, go to manufacturer website and look at BIOS upgrade. I have hard time to believe it has no memory related options while providing possibility to have 4Gb. I suspect BIOS is just unable to handle > 3Gb. |
Tried that one too. No BIOS update available for download.
|
Ok, so what about kernel options for the memory model ? |
|
| Back to top |
|
|
swimmer
Veteran
Joined: 15 Jul 2002
Posts: 1330
Location: Netherlands
|
| Posted: Wed Nov 26, 2008 9:55 am Post subject: |
|
|
Try | Code: | CONFIG_HIGHMEM64G=y
CONFIG_HIGHMEM=y |
instead of ...
HTH
swimmer |
|
| Back to top |
|
|
Naib
Watchman
Joined: 21 May 2004
Posts: 6053
Location: Removed by Neddy
|
| Posted: Wed Nov 26, 2008 9:59 am Post subject: |
|
|
| swimmer wrote: | Try | Code: | CONFIG_HIGHMEM64G=y
CONFIG_HIGHMEM=y |
instead of ...
HTH
swimmer |
not needed for 64bit kernel
_________________
| Quote: | | Removed by Chiitoo |
|
|
| Back to top |
|
|
swimmer
Veteran
Joined: 15 Jul 2002
Posts: 1330
Location: Netherlands
|
| Posted: Wed Nov 26, 2008 10:05 am Post subject: |
|
|
My apologies :-/
I should have read the start of the topic ... |
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 12:55 pm Post subject: |
|
|
| dmpogo wrote: | | Ok, so what about kernel options for the memory model ? |
Here is my entire "Processor type and features" subsection. If there are memory options elsewhere, I'm unaware of them:
| Code: |
│ │ [*] Tickless System (Dynamic Ticks) │ │
│ │ [*] High Resolution Timer Support │ │
│ │ [*] Symmetric multi-processing support │ │
│ │ [*] Enable MPS table │ │
│ │ Subarchitecture Type (PC-compatible) ---> │ │
│ │ [ ] Paravirtualized guest support ---> │ │
│ │ [ ] Memtest │ │
│ │ Processor family (Core 2/newer Xeon) ---> │ │
│ │ [*] Enable DMI scanning │ │
│ │ [*] GART IOMMU support │ │
│ │ [ ] IBM Calgary IOMMU support │ │
│ │ [ ] AMD IOMMU support │ │
│ │ (32) Maximum number of CPUs (2-512) │ │
│ │ [*] SMT (Hyperthreading) scheduler support │ │
│ │ [*] Multi-core scheduler support │ │
│ │ Preemption Model (Preemptible Kernel (Low-Latency Desktop)) ---> │ │
│ │ [ ] Preemptible RCU │ │
│ │ [*] Machine Check Exception │ │
│ │ [*] Intel MCE features │ │
│ │ [ ] AMD MCE features │ │
│ │ < > Dell laptop support │ │
│ │ <M> /dev/cpu/microcode - Intel IA32 CPU microcode support │ │
│ │ <M> /dev/cpu/*/msr - Model-specific register support │ │
│ │ <M> /dev/cpu/*/cpuid - CPU information support │ │
│ │ [*] Numa Memory Allocation and Scheduler Support (EXPERIMENTAL) │ │
│ │ [ ] Old style AMD Opteron NUMA detection │ │
│ │ [*] ACPI NUMA detection │ │
│ │ [ ] NUMA emulation │ │
│ │ (6) Maximum NUMA Nodes (as a power of 2) │ │
│ │ Memory model (Sparse Memory) ---> │ │
│ │ [*] Sparse Memory virtual memmap │ │
│ │ *** Memory hotplug is currently incompatible with Software Suspend *** │ │
│ │ [*] Page migration │ │
│ │ [*] Reserve low 64K of RAM on AMI/Phoenix BIOSen │ │
│ │ [*] MTRR (Memory Type Range Register) support │ │
│ │ [ ] MTRR cleanup support │ │
│ │ [ ] x86 PAT support │ │
│ │ [ ] EFI runtime service support │ │
│ │ [*] Enable seccomp to safely compute untrusted bytecode │ │
│ │ Timer frequency (1000 HZ) ---> │ │
│ │ [*] kexec system call │ │
│ │ [*] kernel crash dumps │ │
│ │ (0x200000) Physical address where the kernel is loaded │ │
│ │ [*] Build a relocatable kernel (EXPERIMENTAL) │ │
│ │ -*- Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL) │ │
│ │ [*] Compat VDSO support │ │
|
I enabled some stuff (such as NUMA) just to see if it would make a difference. I'm not sure if it's needed or even supported. Also, I deliberately deselected any AMD-specific stuff, as this is an Intel motherboard.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
BrummieJim
l33t
Joined: 22 Jul 2005
Posts: 683
|
| Posted: Wed Nov 26, 2008 1:10 pm Post subject: |
|
|
| Have you tried memtest86? |
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 1:42 pm Post subject: |
|
|
Yeah, it only sees 3GB, but then again, it's 32bit.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
bbgermany
Veteran
Joined: 21 Feb 2005
Posts: 1844
Location: Oranienburg/Germany
|
| Posted: Wed Nov 26, 2008 2:05 pm Post subject: |
|
|
Have you checked your BIOS for an option like "Memory Hole Remapping"?
bb
_________________
Desktop: Ryzen 5 5600G, 32GB, 2TB, RX7600
Notebook: Dell XPS 13 9370, 16GB, 1TB
Server #1: Ryzen 5 Pro 4650G, 64GB, 16.5TB
Server #2: Ryzen 4800H, 32GB, 22TB |
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 2:07 pm Post subject: |
|
|
Yes. Please read the thread.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
dmpogo
Advocate
Joined: 02 Sep 2004
Posts: 3286
Location: Canada
|
| Posted: Wed Nov 26, 2008 3:49 pm Post subject: |
|
|
| rev138 wrote: | | dmpogo wrote: | | Ok, so what about kernel options for the memory model ? |
Here is my entire "Processor type and features" subsection. If there are memory options elsewhere, I'm unaware of them:
| Code: |
│ │ [*] Tickless System (Dynamic Ticks) │ │
│ │ [*] High Resolution Timer Support │ │
│ │ [*] Symmetric multi-processing support │ │
│ │ [*] Enable MPS table │ │
│ │ Subarchitecture Type (PC-compatible) ---> │ │
│ │ [ ] Paravirtualized guest support ---> │ │
│ │ [ ] Memtest │ │
│ │ Processor family (Core 2/newer Xeon) ---> │ │
│ │ [*] Enable DMI scanning │ │
│ │ [*] GART IOMMU support │ │
│ │ [ ] IBM Calgary IOMMU support │ │
│ │ [ ] AMD IOMMU support │ │
│ │ (32) Maximum number of CPUs (2-512) │ │
│ │ [*] SMT (Hyperthreading) scheduler support │ │
│ │ [*] Multi-core scheduler support │ │
│ │ Preemption Model (Preemptible Kernel (Low-Latency Desktop)) ---> │ │
│ │ [ ] Preemptible RCU │ │
│ │ [*] Machine Check Exception │ │
│ │ [*] Intel MCE features │ │
│ │ [ ] AMD MCE features │ │
│ │ < > Dell laptop support │ │
│ │ <M> /dev/cpu/microcode - Intel IA32 CPU microcode support │ │
│ │ <M> /dev/cpu/*/msr - Model-specific register support │ │
│ │ <M> /dev/cpu/*/cpuid - CPU information support │ │
│ │ [*] Numa Memory Allocation and Scheduler Support (EXPERIMENTAL) │ │
│ │ [ ] Old style AMD Opteron NUMA detection │ │
│ │ [*] ACPI NUMA detection │ │
│ │ [ ] NUMA emulation │ │
│ │ (6) Maximum NUMA Nodes (as a power of 2) │ │
│ │ Memory model (Sparse Memory) ---> │ │
│ │ [*] Sparse Memory virtual memmap │ │
│ │ *** Memory hotplug is currently incompatible with Software Suspend *** │ │
│ │ [*] Page migration │ │
│ │ [*] Reserve low 64K of RAM on AMI/Phoenix BIOSen │ │
│ │ [*] MTRR (Memory Type Range Register) support │ │
│ │ [ ] MTRR cleanup support │ │
│ │ [ ] x86 PAT support │ │
│ │ [ ] EFI runtime service support │ │
│ │ [*] Enable seccomp to safely compute untrusted bytecode │ │
│ │ Timer frequency (1000 HZ) ---> │ │
│ │ [*] kexec system call │ │
│ │ [*] kernel crash dumps │ │
│ │ (0x200000) Physical address where the kernel is loaded │ │
│ │ [*] Build a relocatable kernel (EXPERIMENTAL) │ │
│ │ -*- Support for suspend on SMP and hot-pluggable CPUs (EXPERIMENTAL) │ │
│ │ [*] Compat VDSO support │ │
|
I enabled some stuff (such as NUMA) just to see if it would make a difference. I'm not sure if it's needed or even supported. Also, I deliberately deselected any AMD-specific stuff, as this is an Intel motherboard. |
There are possible options if you go INSIDE Memory Model (which is Sparse ) right now. See the arrow ?
I am suprised what you said about memtest86 - I was happily checking 8 Gb with it.
Can you enable memtest that comes with the kernel now (see the option in your config !) and boot into it ?
Another things that is strange in your config, is that you have GART IOMMU option. Usually it appears only if EMBEDDED option is chosen
(orresponding Kconfig statement has IF EMBEDDED clause)
Did you choose somewhere that your system is EMBEDDED ? Do 'grep EMBEDDED .config', see that you have
# CONFIG_EMBEDDED is not set |
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 4:24 pm Post subject: |
|
|
| dmpogo wrote: | | There are possible options if you go INSIDE Memory Model (which is Sparse ) right now. See the arrow ? |
No, it just lets me select "Sparse" inside that menu. There are no other options. I see the FLAT and DISCONTIGUOUS options "not set" in the .config, but I assume that menuconfig is concealing these for a reason.
| dmpogo wrote: | I am suprised what you said about memtest86 - I was happily checking 8 Gb with it.
Can you enable memtest that comes with the kernel now (see the option in your config !) and boot into it ? |
I'll try it.
| dmpogo wrote: | Another things that is strange in your config, is that you have GART IOMMU option. Usually it appears only if EMBEDDED option is chosen
(orresponding Kconfig statement has IF EMBEDDED clause)
Did you choose somewhere that your system is EMBEDDED ? Do 'grep EMBEDDED .config', see that you have
# CONFIG_EMBEDDED is not set |
Yeah. Looks like that was something genkernel did that I missed when I pruned it. I disabled the embedded option and now GART IOMMU is gone.
I am trying the -r4 kernel to see if there is yet another slight change in memory totals with that one.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 4:40 pm Post subject: |
|
|
I ran memtest86 and memtest86+. Both report "3001 MB".
I then booted into the 2.6.27-r4 kernel and now 'free' shows:
| Code: |
total used free shared buffers cached
Mem: 3024688 672736 2351952 0 73480 248580
-/+ buffers/cache: 350676 2674012
Swap: 1048568 0 1048568
|
This is a little bit LESS than -r3, but MORE than -r2
To be fair, I've been tweaking the kernel config between versions, but it still seems that the kernel does have some effect on how much memory it sees.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
dmpogo
Advocate
Joined: 02 Sep 2004
Posts: 3286
Location: Canada
|
| Posted: Wed Nov 26, 2008 7:05 pm Post subject: |
|
|
| rev138 wrote: | I ran memtest86 and memtest86+. Both report "3001 MB".
I then booted into the 2.6.27-r4 kernel and now 'free' shows:
| Code: |
total used free shared buffers cached
Mem: 3024688 672736 2351952 0 73480 248580
-/+ buffers/cache: 350676 2674012
Swap: 1048568 0 1048568
|
This is a little bit LESS than -r3, but MORE than -r2
To be fair, I've been tweaking the kernel config between versions, but it still seems that the kernel does have some effect on how much memory it sees. |
I don't think this minute kernel dependence matter (of course I can be wrong). As you may notice, 3 GB=3145728 KB,
so from the output of free, there are ~120 MB are reserved for something even from 3GB. Perhaps memory used by kernel is among these anyway, so some variations are possible from kernel to kernel. |
|
| Back to top |
|
|
rev138
l33t
Joined: 19 Jun 2003
Posts: 848
Location: Vermont, USA
|
| Posted: Wed Nov 26, 2008 8:12 pm Post subject: |
|
|
Just to be extra anal, I removed one of the chips, booted into the BIOS, and confirmed that it has 2GB, then I did the same with the other chip, and finally put them both back in, swapping their original position in the slots. No change.
_________________
Vermont Free PC
http://www.vtfreepc.org |
|
| Back to top |
|
|
|
Kernel & Hardware
