On 5/30/07, Robert Hancock <[email protected]> wrote:
Justin Piszcz wrote:
> That output looked nasty, attaching entries from syslog.
>
> Justin.
Here's your E820 memory map, from dmesg:
BIOS-e820: 0000000000000000 - 000000000008f000 (usable)
BIOS-e820: 000000000008f000 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 00000000cf58f000 (usable)
BIOS-e820: 00000000cf58f000 - 00000000cf59c000 (reserved)
BIOS-e820: 00000000cf59c000 - 00000000cf653000 (usable)
BIOS-e820: 00000000cf653000 - 00000000cf6a5000 (ACPI NVS)
BIOS-e820: 00000000cf6a5000 - 00000000cf6a8000 (ACPI data)
BIOS-e820: 00000000cf6a8000 - 00000000cf6ef000 (ACPI NVS)
BIOS-e820: 00000000cf6ef000 - 00000000cf6f1000 (ACPI data)
BIOS-e820: 00000000cf6f1000 - 00000000cf6f2000 (usable)
BIOS-e820: 00000000cf6f2000 - 00000000cf6ff000 (ACPI data)
BIOS-e820: 00000000cf6ff000 - 00000000cf700000 (usable)
BIOS-e820: 00000000cf700000 - 00000000d0000000 (reserved)
BIOS-e820: 00000000fff00000 - 0000000100000000 (reserved)
BIOS-e820: 0000000100000000 - 000000022c000000 (usable)
so the usable memory ranges are:
0-572K
1MB-3317.55MB
3317.60MB-3317.75MB
3318.94MB-3318.945MB
3318.996MB-3319MB
4096MB-8896MB
and the MTRRs (from /proc/mtrr, from private email):
reg00: base=0x00000000 ( 0MB), size=2048MB: write-back, count=1
reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
reg02: base=0xc0000000 (3072MB), size= 256MB: write-back, count=1
reg03: base=0xcf800000 (3320MB), size= 8MB: uncachable, count=1
reg04: base=0xcf700000 (3319MB), size= 1MB: uncachable, count=1
reg05: base=0x100000000 (4096MB), size=4096MB: write-back, count=1
reg06: base=0x200000000 (8192MB), size= 512MB: write-back, count=1
reg07: base=0x220000000 (8704MB), size= 128MB: write-back, count=1
so the ranges mapped as cacheable are:
0-3319MB
4096-8832MB
leaving 64MB of memory at the top of RAM uncached. What do you want to
bet that something important (kernel code?) is getting loaded there..
So essentially it's a BIOS problem, it's not setting up the MTRRs
properly in order to map all of RAM as cacheable. As Andi says, complain
to Intel.
the BIOS used up of VAR MTRR ( = 8).
it supposed change to sth like
reg00: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1
reg01: base=, size=64MB: uncachable, count=1
reg02: base=, size=128MB: uncachable, count=1
reg03: base=, size=512MB: uncachable, count=1
reg04: base=0x100000000 (4096MB), size=4096MB: write-back, count=1
reg05: base=0x200000000 (8192MB), size= 512MB: write-back, count=1
reg06: base=0x220000000 (8704MB), size= 128MB: write-back, count=1
reg07: base=(8832MB), size= 64MB: write-back, count=1
or you can set var mtrr and then use kexec to load another kernel.
AMD Rev F later cpu, will assume 4G above is write back, and even
without var mtrr for it.
YH
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