RAM installed vs reported

RAM installed vs reported

[Thanasis]

I have a netbook (Acer Aspire One A110L) and installed a 1GB DDR2 in the
available slot, for a total of 1.5GB or RAM.
The BIOS reports it as 1.5GB and so does grml linux (booting from usb),
but the installed gentoo linux reports only 904600 kB:

# free
             total       used       free     shared    buffers     cached
Mem:        904600      82316     822284          0       9752      37712
-/+ buffers/cache:      34852     869748
Swap:      1638588          0    1638588

# cat /proc/meminfo
MemTotal:         904600 kB
MemFree:          822284 kB
Buffers:            9752 kB
Cached:            37712 kB
SwapCached:            0 kB
Active:            32232 kB
Inactive:          28780 kB
Active(anon):      13848 kB
Inactive(anon):        0 kB
Active(file):      18384 kB
Inactive(file):    28780 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:       1638588 kB
SwapFree:        1638588 kB
Dirty:                 4 kB
Writeback:             0 kB
AnonPages:         13548 kB
Mapped:            11256 kB
Shmem:               300 kB
Slab:              10356 kB
SReclaimable:       6132 kB
SUnreclaim:         4224 kB
KernelStack:        1424 kB
PageTables:          892 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     2090888 kB
Committed_AS:      73552 kB
VmallocTotal:     122880 kB
VmallocUsed:        9688 kB
VmallocChunk:     109832 kB
DirectMap4k:       11832 kB
DirectMap4M:      905216 kB

I suspect it has to do with my kernel (2.6.32-gentoo-r1) configuration,
but do not know where to look.
Any suggestions ?

Re: [gentoo-user] RAM installed vs reported

[Thanasis]

on 12/30/2009 01:08 PM Dirk Heinrichs wrote the following:
> Am Mittwoch 30 Dezember 2009 11:49:39 schrieb Thanasis:
>> I have a netbook (Acer Aspire One A110L) and installed a 1GB DDR2 in the
>> available slot, for a total of 1.5GB or RAM.
>> The BIOS reports it as 1.5GB and so does grml linux (booting from usb),
>> but the installed gentoo linux reports only 904600 kB:
>
> With more than 1G of memory, you should set CONFIG_HIGHMEM4G=y.
> HTH...
> 	Dirk
I thought CONFIG_HIGHMEM4G had to do with more than 4GB of RAM.
Now I can see that the associated help says it is for an amount between
1 and 4GB.
That should be it. The option name confused me.
I will try it and report back.
Thanks :-)

Re: [gentoo-user] RAM installed vs reported

[Krzysztof Halasa]

Thanasis <thanasis@asyr.hopto.org> writes:

> I thought CONFIG_HIGHMEM4G had to do with more than 4GB of RAM.
> Now I can see that the associated help says it is for an amount between
> 1 and 4GB.

Depends on the "split" used. With 2 GB : 2 GB you can have all-lowmem
1.5 GB RAM, without CONFIG_HIGHMEM*. 2 GB of per-process address space
is usually not a problem.

x86-64 removes such limits.
-- 
Krzysztof Halasa

Re: [gentoo-user] RAM installed vs reported

[Thanasis]

on 12/31/2009 04:59 PM Krzysztof Halasa wrote the following:
> Thanasis <thanasis@asyr.hopto.org> writes:
>
>> I thought CONFIG_HIGHMEM4G had to do with more than 4GB of RAM.
>> Now I can see that the associated help says it is for an amount between
>> 1 and 4GB.
>
> Depends on the "split" used. With 2 GB : 2 GB you can have all-lowmem
> 1.5 GB RAM, without CONFIG_HIGHMEM*. 2 GB of per-process address space
> is usually not a problem.
How do you implement that? What do you mean 2GB:2GB split ?

Re: [gentoo-user] RAM installed vs reported

[Krzysztof Halasa]

Thanasis <thanasis@asyr.hopto.org> writes:

>> Depends on the "split" used. With 2 GB : 2 GB you can have all-lowmem
>> 1.5 GB RAM, without CONFIG_HIGHMEM*. 2 GB of per-process address space
>> is usually not a problem.
> How do you implement that? What do you mean 2GB:2GB split ?

See "make menuconfig", Processor type and features -> Memory split. You
need to select "EMBEDDED" and "EXPERIMENTAL" first. What you need for
1.5 GB RAM is VMSPLIT_2G.

The idea is that the CPU address space is divided: ca. 2 GB (in this
configuration) for user space (for each process - instead of 3 GB),
2 GB - 128 MB (or something like that, I don't remember exactly) for
physical RAM, and the last 128 MB or so for PCI devices and other
things.
-- 
Krzysztof Halasa

Re: [gentoo-user] RAM installed vs reported

[Thanasis]

on 01/01/2010 03:38 PM Krzysztof Halasa wrote the following:
> Thanasis <thanasis@asyr.hopto.org> writes:
>
>   
>>> Depends on the "split" used. With 2 GB : 2 GB you can have all-lowmem
>>> 1.5 GB RAM, without CONFIG_HIGHMEM*. 2 GB of per-process address space
>>> is usually not a problem.
>>>       
>> How do you implement that? What do you mean 2GB:2GB split ?
>>     
> See "make menuconfig", Processor type and features -> Memory split. You
> need to select "EMBEDDED" and "EXPERIMENTAL" first. What you need for
> 1.5 GB RAM is VMSPLIT_2G.
>
> The idea is that the CPU address space is divided: ca. 2 GB (in this
> configuration) for user space (for each process - instead of 3 GB),
> 2 GB - 128 MB (or something like that, I don't remember exactly) for
> physical RAM, and the last 128 MB or so for PCI devices and other
> things.
>   
Hmm..., but are EMBEDDED options suitable for a netbook like the A110L ?

Re: [gentoo-user] RAM installed vs reported

[Krzysztof Halasa]

Thanasis <thanasis@asyr.hopto.org> writes:

> Hmm..., but are EMBEDDED options suitable for a netbook like the A110L ?

This "EMBEDDED" just means "don't touch these unless you really know
what you're doing".

BTW I remember using VMSPLIT 2 GB : 2 GB on server-class machines,
before they were upgraded to x86-64.
-- 
Krzysztof Halasa

Re: [gentoo-user] RAM installed vs reported

[Thanasis]

on 01/04/2010 01:10 AM Krzysztof Halasa wrote the following:
> Thanasis <thanasis@asyr.hopto.org> writes:
>
>   
>> Hmm..., but are EMBEDDED options suitable for a netbook like the A110L ?
>>     
> This "EMBEDDED" just means "don't touch these unless you really know
> what you're doing".
>
> BTW I remember using VMSPLIT 2 GB : 2 GB on server-class machines,
> before they were upgraded to x86-64.
>   
Do you mean that I should try it? Is there any gain over using
CONFIG_HIGHMEM4G ?

Re: [gentoo-user] RAM installed vs reported

[Krzysztof Halasa]

Thanasis <thanasis@asyr.hopto.org> writes:

> Do you mean that I should try it? Is there any gain over using
> CONFIG_HIGHMEM4G ?

You may want to try, HIGHMEM4G is (may be) slower, depending on load.
Google should find something about that.
-- 
Krzysztof Halasa

Re: [gentoo-user] RAM installed vs reported

[Thanasis]

on 01/04/2010 07:51 PM Thanasis wrote the following:
> on 01/04/2010 04:51 PM Joshua Murphy wrote the following:
>> 2010/1/3 Thanasis <thanasis@asyr.hopto.org>:
>>   
>>> on 01/04/2010 01:10 AM Krzysztof Halasa wrote the following:
>>>     
>>>> Thanasis <thanasis@asyr.hopto.org> writes:
>>>>
>>>>       
>>>>> Hmm..., but are EMBEDDED options suitable for a netbook like the A110L ?
>>>>>
>>>> This "EMBEDDED" just means "don't touch these unless you really know
>>>> what you're doing".
>>>>
>>>> BTW I remember using VMSPLIT 2 GB : 2 GB on server-class machines,
>>>> before they were upgraded to x86-64.
>>>>
>>>>       
>>> Do you mean that I should try it? Is there any gain over using
>>> CONFIG_HIGHMEM4G ?
>>>     
>> Likely nothing noticeable, but here's a bit of a good coverage of the topic:
>>
>> http://kerneltrap.org/node/6067
>>
> Thanks, I think I'll give it a try. :-)
I tried option: 2G/2G user/kernel split (for full 2G low memory), but X
would not start. So i reverted back to CONFIG_HIGHMEM4G.

Re: [gentoo-user] RAM installed vs reported

[Krzysztof Halasa]

Thanasis <thanasis@asyr.hopto.org> writes:

> I tried option: 2G/2G user/kernel split (for full 2G low memory), but X
> would not start. So i reverted back to CONFIG_HIGHMEM4G.

Binary proprietary module maybe?
-- 
Krzysztof Halasa

Re: [SOLVED] RAM installed vs reported

[Thanasis]

on 12/30/2009 01:08 PM Dirk Heinrichs wrote the following:
> Am Mittwoch 30 Dezember 2009 11:49:39 schrieb Thanasis:
>
>> I have a netbook (Acer Aspire One A110L) and installed a 1GB DDR2 in the
>> available slot, for a total of 1.5GB or RAM.
>> The BIOS reports it as 1.5GB and so does grml linux (booting from usb),
>> but the installed gentoo linux reports only 904600 kB:
>
> With more than 1G of memory, you should set CONFIG_HIGHMEM4G=y.
>
> HTH...
>
> 	Dirk
That did it !
Thanks again.
:-)

Re: [SOLVED] RAM installed vs reported

[Bill Davidsen]

Thanasis wrote:
> on 12/30/2009 01:08 PM Dirk Heinrichs wrote the following:
>> Am Mittwoch 30 Dezember 2009 11:49:39 schrieb Thanasis:
>>
>>> I have a netbook (Acer Aspire One A110L) and installed a 1GB DDR2 in the
>>> available slot, for a total of 1.5GB or RAM.
>>> The BIOS reports it as 1.5GB and so does grml linux (booting from usb),
>>> but the installed gentoo linux reports only 904600 kB:
>> With more than 1G of memory, you should set CONFIG_HIGHMEM4G=y.
>>
Another benefit with PAE is that you get the benefit of the nx bit being 
available to eliminate several classes to deliberate and unintentional misbehavior.

-- 
Bill Davidsen <davidsen@tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot