Re: Missing RAM on x86_64

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Mike Richards a écrit :
Hi, I appear to be missing quite a bit of RAM on an x86_64 system. I
have 1GB installed, but 'free' only shows 878MB:

pokey$ free -m
            total       used       free     shared    buffers     cached
Mem:           878        571        306          0         52        332
-/+ buffers/cache:        186        691
Swap:         1023          0       1023

I'm used to seeing a little bit of RAM missing with 32bit systems, but
146MB seems a bit much. The part of dmesg that concerns the RAM is
shown below. Anyone know what's up here? Is this normal for an x86_64
system?

Linux version 2.6.20.11 (root@pokey) (gcc version 4.1.2) #1 SMP Thu
May 24 18:29:52 GMT 2007
Command line: auto BOOT_IMAGE=2.6.20.11 rw root=801
BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 0000000037fd0000 (usable)
BIOS-e820: 0000000037fd0000 - 0000000037fde000 (ACPI data)
BIOS-e820: 0000000037fde000 - 0000000038000000 (ACPI NVS)
BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved)
BIOS-e820: 00000000fee00000 - 00000000fef00000 (reserved)
BIOS-e820: 00000000ff780000 - 0000000100000000 (reserved)


I would say your BIOS needs an update or some tweakings.

The (usable) parts that it gives to the OS (linux) are :

0000000000000000 - 000000000009fc00
0000000000100000 - 0000000037fd0000

Thats not 1024 MB, but 892 MB

Here is the output on a 16 GB x86_64 machine

BIOS-provided physical RAM map:
 BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
 BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
 BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
 BIOS-e820: 0000000000100000 - 000000007fff0000 (usable)
 BIOS-e820: 000000007fff0000 - 000000007ffff000 (ACPI data)
 BIOS-e820: 000000007ffff000 - 0000000080000000 (ACPI NVS)
 BIOS-e820: 00000000ff780000 - 0000000100000000 (reserved)
 BIOS-e820: 0000000100000000 - 0000000480000000 (usable)

On node 0 totalpages: 2097039
On node 1 totalpages: 2097152

total of 4194078 pages (while exact 16GB should be 4194304 pages)


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux