HIGHMEM

[Nagy Tibor]

Hi,

We have two Dell Poweredge servers, an older one (PowerEdge 6300) and a 
newer one (PowerEdge 6400). Both servers have 4GB RAM, but the Linux 
kernel uses about 500MB less memory in the newer machine.

See /var/log/boot.msg on the old one:

<4>Linux version 2.4.20 (root@dell632) (gcc version 2.95.3 20010315
(SuSE)) #4 SMP Fri Jan 10 12:07:00 CET 2003
<6>BIOS-provided physical RAM map:
<4> BIOS-e820: 0000000000000000 - 00000000000a0000 (usable)
<4> BIOS-e820: 0000000000100000 - 00000000fbffe000 (usable)
<4> BIOS-e820: 00000000fbffe000 - 00000000fc000000 (reserved)
<4> BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
<4> BIOS-e820: 00000000fee00000 - 00000000fee10000 (reserved)
<4> BIOS-e820: 00000000fff80000 - 0000000100000000 (reserved)
<5>3135MB HIGHMEM available.
<5>896MB LOWMEM available.

and on the new one:

<4>Linux version 2.4.20 (root@alfa) (gcc version 2.95.3 20010315 (SuSE))
#10 SMP Fri Mar 28 15:40:45 CET 2003
<6>BIOS-provided physical RAM map:
<4> BIOS-e820: 0000000000000000 - 00000000000a0000 (usable)
<4> BIOS-e820: 0000000000100000 - 00000000dfff0000 (usable)
<4> BIOS-e820: 00000000dfff0000 - 00000000dfffec00 (ACPI data)
<4> BIOS-e820: 00000000dfffec00 - 00000000dffff000 (reserved)
<4> BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
<4> BIOS-e820: 00000000fee00000 - 00000000fee10000 (reserved)
<4> BIOS-e820: 00000000fff80000 - 0000000100000000 (reserved)
<5>2687MB HIGHMEM available.
<5>896MB LOWMEM available.

There is a big hole between 00000000dffff000 and 00000000fec00000, which
is not used on the new machine. What can I do?

Thanks for your help.

Tibor

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Tibor Nagy
E-mail: [e-mail]
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