PAE-kernel?

[Johann Spies <jspies@xxxxxxxxx>]

In dmesg on a server with 4Gb Ram I read:

BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 00000000000a0000 (usable)
 BIOS-e820: 0000000000100000 - 00000000bffc0000 (usable)
 BIOS-e820: 00000000bffc0000 - 00000000bffcfc00 (ACPI data)
 BIOS-e820: 00000000bffcfc00 - 00000000bffff000 (reserved)
 BIOS-e820: 00000000e0000000 - 00000000fec90000 (reserved)
 BIOS-e820: 00000000fed00000 - 00000000fed00400 (reserved)
 BIOS-e820: 00000000fee00000 - 00000000fee10000 (reserved)
 BIOS-e820: 00000000ffb00000 - 0000000100000000 (reserved)
 BIOS-e820: 0000000100000000 - 0000000140000000 (usable)
Warning only 4GB will be used.
Use a PAE enabled kernel.
3200MB HIGHMEM available.
896MB LOWMEM available.

Top reports:

Mem:   3105844k total

and free -m:

$ free -m
         total       used       free     shared    buffers  cached
Mem:      3033       2853        179          0        407   2132

I have search Google about this and according to an answer of Alan Cox
a memory map like this will case the last part 
( BIOS-e820: 0000000100000000 - 0000000140000000 (usable))  not to be
used.   It also seems that PAE-enabled kernels are a bit slower than
the others if I understand it correctly.

I am using a 2.6.12 kernel here and could not find anything in the
kernel documentation about how to enable a PAE kernel.  In the menu
(from make menuconfig)  there was no menu-option about PAE.  When I
search for PAE I found:  "Symbol: X86_PAE [=n] ".  So I put
CONFIG_X86_PAE=y in .config but it was removed when I built the
kernel.


There are references to using the kernel parameter mem=  in
conjunction with mmap= but I am not sure how to use it in this case.

I have also come across a kernel patch
"kernel-patch-lkcd_7.0.5.1_all.deb" but I am not sure how trustworthy
it is.
 
Any ideas on how to get my kernel to use the full memory?


Regards
Johann
-- 
Johann Spies          Telefoon: 021-808 4036
Informasietegnologie, Universiteit van Stellenbosch

     "Trust in the Lord with all your heart, and do not
      lean on your own understanding."
                                        Proverbs 3:5


Vrywaring:  Jy hoef eintlik net die e-pos self te gelees het. :)
Disclaimer: If you are reading this you are wasting your time :)
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