Memory not being reported

Memory not being reported

[David Ronis]

I'm running 2.6.28.1 on an i686 (slackware-12.1 for the most part) box.
I recently added some extra memory, expanding from 2Gb to 4.  Everything
works as expected except that not all of the memory seems to be seen.

free returns:

             total       used       free     shared    buffers
cached
Mem:       3374860    2099504    1275356          0      86612
1032024
-/+ buffers/cache:     980868    2393992
Swap:       497972          0     497972


and cat /proc/meminfo gives:

MemTotal:        3374860 kB
MemFree:         1199184 kB
Buffers:           86816 kB
Cached:          1036240 kB
SwapCached:            0 kB
Active:          1375864 kB

etc.

On the other hand, user-space tools like lshw show the 4 1Gb DIMMS as
does the BIOS configuration boot menu.

One suspicion is that the configure option CONFIG_HIGHMEM4G=y
should be unset and the CONFIG_HIGHMEM64G  should be.

Any help would be appreciated, as would a separate CC since I don't
subscribe to the list.

Thanks in advance

David

Re: Memory not being reported

[Wakko Warner]

David Ronis wrote:
> I'm running 2.6.28.1 on an i686 (slackware-12.1 for the most part) box.
> I recently added some extra memory, expanding from 2Gb to 4.  Everything
> works as expected except that not all of the memory seems to be seen.

I'm running on 2.6.24.3 right now which is irrelevent.  Is your system
x86_64 capable?  This specific machine is not.  It's an older dual xeon 533mhz
fsb.

> free returns:
> 
>              total       used       free     shared    buffers
> cached
> Mem:       3374860    2099504    1275356          0      86612
> 1032024
> -/+ buffers/cache:     980868    2393992
> Swap:       497972          0     497972

             total       used       free     shared    buffers     cached
Mem:       4019196    1342956    2676240          0     405712     223672
-/+ buffers/cache:     713572    3305624
Swap:            0          0          0


> On the other hand, user-space tools like lshw show the 4 1Gb DIMMS as
> does the BIOS configuration boot menu.

lshw IIRC uses dmi information to obtain that information.

> One suspicion is that the configure option CONFIG_HIGHMEM4G=y
> should be unset and the CONFIG_HIGHMEM64G  should be.

# grep HIGH .config
# CONFIG_HIGH_RES_TIMERS is not set
# CONFIG_NOHIGHMEM is not set
# CONFIG_HIGHMEM4G is not set
CONFIG_HIGHMEM64G=y
CONFIG_HIGHMEM=y
# CONFIG_HIGHPTE is not set
# 

I see no reason not to use highmem 64gb  I've used it on several of my
systems, even ones that can't handle more than 2gb w/o problems.

One thing I have noticed (which is irrelevent to your question) is that I
see about 100mb less memory running a 64-bit kernel vs a 32-bit kernel on 2
systems (different brand of motherboard) and 4gb.  One was upgraded to 8gb;
32-bit shows about 8400000kb memory and running 64-bit shows about 8200000kb
memory.  Noone has answered my question as to why that is.

-- 
 Lab tests show that use of micro$oft causes cancer in lab animals
 Got Gas???

Re: Memory not being reported

[markus reichelt]

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* David Ronis <ronis@ronispc.chem.mcgill.ca> wrote:

> I'm running 2.6.28.1 on an i686 (slackware-12.1 for the most part)
> box. I recently added some extra memory, expanding from 2Gb to 4. 
> Everything works as expected except that not all of the memory
> seems to be seen.

I've got a comparable system, and could only see about 3G of the
installed 4G.


> One suspicion is that the configure option CONFIG_HIGHMEM4G=y
> should be unset and the CONFIG_HIGHMEM64G  should be.

Indeed, using CONFIG_HIGHMEM64G does the trick for me, 4G usuable.

(I've also CONFIG_RESOURCES_64BIT set, maybe that's needed as well)

-- 
left blank, right bald

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Re: Memory not being reported

[Robert Hancock]

David Ronis wrote:
> I'm running 2.6.28.1 on an i686 (slackware-12.1 for the most part) box.
> I recently added some extra memory, expanding from 2Gb to 4.  Everything
> works as expected except that not all of the memory seems to be seen.
> 
> free returns:
> 
>              total       used       free     shared    buffers
> cached
> Mem:       3374860    2099504    1275356          0      86612
> 1032024
> -/+ buffers/cache:     980868    2393992
> Swap:       497972          0     497972
> 
> 
> and cat /proc/meminfo gives:
> 
> MemTotal:        3374860 kB
> MemFree:         1199184 kB
> Buffers:           86816 kB
> Cached:          1036240 kB
> SwapCached:            0 kB
> Active:          1375864 kB
> 
> etc.
> 
> On the other hand, user-space tools like lshw show the 4 1Gb DIMMS as
> does the BIOS configuration boot menu.
> 
> One suspicion is that the configure option CONFIG_HIGHMEM4G=y
> should be unset and the CONFIG_HIGHMEM64G  should be.

Yes, it should be. However, if your chipset doesn't support remapping 
memory above the 4GB mark (some don't, and this is needed in this case 
because various IO areas use up some of the address space below 4GB) 
then it won't be possible to make use of any of that RAM.

Note that when running with more than 4GB of RAM it's generally 
preferable to run a 64-bit kernel if the machine supports it.

> 
> Any help would be appreciated, as would a separate CC since I don't
> subscribe to the list.
> 
> Thanks in advance
> 
> David
> 

Re: Memory not being reported

[David Ronis]

I don't think this is a 64bit capable box.  Nonetheless, there are only
4G of memory, not more, and I still see 3G of it.

David



On Sat, 2009-01-24 at 02:37 -0600, Robert Hancock wrote:
> David Ronis wrote:
> > I'm running 2.6.28.1 on an i686 (slackware-12.1 for the most part) box.
> > I recently added some extra memory, expanding from 2Gb to 4.  Everything
> > works as expected except that not all of the memory seems to be seen.
> > 
> > free returns:
> > 
> >              total       used       free     shared    buffers
> > cached
> > Mem:       3374860    2099504    1275356          0      86612
> > 1032024
> > -/+ buffers/cache:     980868    2393992
> > Swap:       497972          0     497972
> > 
> > 
> > and cat /proc/meminfo gives:
> > 
> > MemTotal:        3374860 kB
> > MemFree:         1199184 kB
> > Buffers:           86816 kB
> > Cached:          1036240 kB
> > SwapCached:            0 kB
> > Active:          1375864 kB
> > 
> > etc.
> > 
> > On the other hand, user-space tools like lshw show the 4 1Gb DIMMS as
> > does the BIOS configuration boot menu.
> > 
> > One suspicion is that the configure option CONFIG_HIGHMEM4G=y
> > should be unset and the CONFIG_HIGHMEM64G  should be.
> 
> Yes, it should be. However, if your chipset doesn't support remapping 
> memory above the 4GB mark (some don't, and this is needed in this case 
> because various IO areas use up some of the address space below 4GB) 
> then it won't be possible to make use of any of that RAM.
> 
> Note that when running with more than 4GB of RAM it's generally 
> preferable to run a 64-bit kernel if the machine supports it.
> 
> > 
> > Any help would be appreciated, as would a separate CC since I don't
> > subscribe to the list.
> > 
> > Thanks in advance
> > 
> > David
> > 
> 

Re: Memory not being reported

[Robert Hancock]

David Ronis wrote:
> I don't think this is a 64bit capable box.  Nonetheless, there are only
> 4G of memory, not more, and I still see 3G of it.

Can you post your dmesg output from bootup?

> 
> David
> 
> 
> 
> On Sat, 2009-01-24 at 02:37 -0600, Robert Hancock wrote:
>> David Ronis wrote:
>>> I'm running 2.6.28.1 on an i686 (slackware-12.1 for the most part) box.
>>> I recently added some extra memory, expanding from 2Gb to 4.  Everything
>>> works as expected except that not all of the memory seems to be seen.
>>>
>>> free returns:
>>>
>>>              total       used       free     shared    buffers
>>> cached
>>> Mem:       3374860    2099504    1275356          0      86612
>>> 1032024
>>> -/+ buffers/cache:     980868    2393992
>>> Swap:       497972          0     497972
>>>
>>>
>>> and cat /proc/meminfo gives:
>>>
>>> MemTotal:        3374860 kB
>>> MemFree:         1199184 kB
>>> Buffers:           86816 kB
>>> Cached:          1036240 kB
>>> SwapCached:            0 kB
>>> Active:          1375864 kB
>>>
>>> etc.
>>>
>>> On the other hand, user-space tools like lshw show the 4 1Gb DIMMS as
>>> does the BIOS configuration boot menu.
>>>
>>> One suspicion is that the configure option CONFIG_HIGHMEM4G=y
>>> should be unset and the CONFIG_HIGHMEM64G  should be.
>> Yes, it should be. However, if your chipset doesn't support remapping 
>> memory above the 4GB mark (some don't, and this is needed in this case 
>> because various IO areas use up some of the address space below 4GB) 
>> then it won't be possible to make use of any of that RAM.
>>
>> Note that when running with more than 4GB of RAM it's generally 
>> preferable to run a 64-bit kernel if the machine supports it.
>>
>>> Any help would be appreciated, as would a separate CC since I don't
>>> subscribe to the list.
>>>
>>> Thanks in advance
>>>
>>> David
>>>
>