Red Hat Bugzilla – Bug 65284
Bigmem kernel sees only 4.75 of 5GB on a slimmerlot
Last modified: 2007-04-18 12:42:41 EDT
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Description of problem:
On a slimmerlot with A02 Bios, 5GB ram, and 7.3 (2.4.18-3bigmem) installed.
/Proc/meminfo reports only 4.75GB. Machine bios reports 5.120GB.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1.Install 7.3 on a slimmerlot w/ 5GB ram
2.Note /proc/meminfo memory amount
Actual Results: 4.75 of 5GB shown
Expected Results: 5 of 5GB shown
Created attachment 58095 [details]
If you count the memory in the "usable" regions in the e820 table it adds up
to about 4669 Mb. I think you should ask your bios folks how this table says 5Gb
since it clearly doesn't.....
This is working as designed. The chipset cannot remap physical RAM out of
address space reserved for PCI devices into any other address space. This
means that PCI devices like PERC3 cards, which request 128MB of address space,
get it, and the system "loses" 128MB of RAM. This is a property of all
existing ServerWorks chipsets. Other platforms which use Intel chipsets may
not have this limitation.
*** Bug 62123 has been marked as a duplicate of this bug. ***