Messages in this thread | | | Date | Sat, 18 Apr 2009 11:15:09 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 2/3] pci: don't assume pref memio are 64bit -v2 |
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* Yinghai Lu <yinghai@kernel.org> wrote:
> one system with 4g installed ( there is 1g hole) > > when 4G installed. > BIOS put ACPI etc need the hole > [ 0.000000] BIOS-provided physical RAM map: > [ 0.000000] BIOS-e820: 0000000000000000 - 000000000009bc00 (usable) > [ 0.000000] BIOS-e820: 000000000009bc00 - 00000000000a0000 (reserved) > [ 0.000000] BIOS-e820: 00000000000e3000 - 0000000000100000 (reserved) > [ 0.000000] BIOS-e820: 0000000000100000 - 00000000bffa0000 (usable) > [ 0.000000] BIOS-e820: 00000000bffa0000 - 00000000bffae000 (ACPI data) > [ 0.000000] BIOS-e820: 00000000bffae000 - 00000000bfff0000 (ACPI NVS) > [ 0.000000] BIOS-e820: 00000000bfff0000 - 00000000c0000000 (reserved) > [ 0.000000] BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved) > [ 0.000000] BIOS-e820: 00000000ffb00000 - 0000000100000000 (reserved) > [ 0.000000] BIOS-e820: 0000000100000000 - 0000000140000000 (usable) > so in kernel resource will be reserved for 0xbffa0000 - 0xbfff0000 for ACPI > 0x100000 - 0xbffa0000 for RAM...
btw., sidenote, it would be nice to enhance the e820 table printout with size and hole info as well. I did this manually yesterday in another mail:
BIOS-provided physical RAM map: BIOS-e820: 0000000000000000 - 000000000009fc00 (usable) 0.639 MB RAM BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved) 0.001 MB [ hole ] 0.250 MB BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved) 0.125 MB BIOS-e820: 0000000000100000 - 000000003ed94000 (usable) 1004.5 MB RAM BIOS-e820: 000000003ed94000 - 000000003ee4e000 (ACPI NVS) 0.7 MB BIOS-e820: 000000003ee4e000 - 000000003fea2000 (usable) 16.3 MB RAM BIOS-e820: 000000003fea2000 - 000000003fee9000 (ACPI NVS) 0.3 MB BIOS-e820: 000000003fee9000 - 000000003feed000 (usable) 0.15 MB RAM BIOS-e820: 000000003feed000 - 000000003feff000 (ACPI data 0.07 MB BIOS-e820: 000000003feff000 - 000000003ff00000 (usable) 0.004 MB RAM [ hole ] 1.0 MB [ hole ] 3072.0 MB
it would be extremely useful to have that in the printout, to see the physical address space layout at a glance. Small holes are easy to miss, and e820 entry sizes are hard to judge at a glance.
To make this fit well, i'd suggest to drop the 'BIOS-e820: ' prefix - it's redundant.
Ingo
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