Re: [PATCH] x86_32: trim memory by updating e820 v3

From: Gabriel C
Date: Mon Apr 28 2008 - 05:18:59 EST


Yinghai Lu wrote:
> On Sat, Apr 26, 2008 at 5:56 AM, Gabriel C <nix.or.die@xxxxxxxxxxxxxx> wrote:
>> Andrew Morton wrote:
>> > On Tue, 22 Jan 2008 16:23:20 -0800 Yinghai Lu <Yinghai.Lu@xxxxxxx> wrote:
>> >
>> >> [PATCH] x86_32: trim memory by updating e820 v3
>> >>
>> >> when mtrr is not covering all e820 table, need to trim the ram, need to update e820
>> >>
>> >> reuse some code for x86_64
>> >>
>> >> here need to add early_get_cap and use it in early_cpu_detect, and move mtrr_bp_init early
>> >>
>> >> need Justine to test with his special system with bug bios.
>> >>
>> >> Signed-off-by: Yinghai Lu <yinghai.lu@xxxxxxx>
>> >
>> > Speaking of mtrr and e820....
>> >
>> > Could someone please take a peek at
>> > http://bugzilla.kernel.org/show_bug.cgi?id=10508 ?
>> >
>> > For some reason we seem to have turned this:
>> >
>> > [ 0.000000] BIOS-e820: 0000000000000000 - 000000000009f800 (usable)
>> > [ 0.000000] BIOS-e820: 000000000009f800 - 00000000000a0000 (reserved)
>> > [ 0.000000] BIOS-e820: 00000000000dc000 - 0000000000100000 (reserved)
>> > [ 0.000000] BIOS-e820: 0000000000100000 - 00000000bf6d0000 (usable)
>> > [ 0.000000] BIOS-e820: 00000000bf6d0000 - 00000000bf6e3000 (ACPI NVS)
>> > [ 0.000000] BIOS-e820: 00000000bf6e3000 - 00000000c0000000 (reserved)
>> > [ 0.000000] BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
>> > [ 0.000000] BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
>> > [ 0.000000] BIOS-e820: 00000000fed00000 - 00000000fed00400 (reserved)
>> > [ 0.000000] BIOS-e820: 00000000fed14000 - 00000000fed1a000 (reserved)
>> > [ 0.000000] BIOS-e820: 00000000fed1c000 - 00000000fed90000 (reserved)
>> > [ 0.000000] BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
>> > [ 0.000000] BIOS-e820: 00000000ff000000 - 0000000100000000 (reserved)
>> > [ 0.000000] BIOS-e820: 0000000100000000 - 0000000140000000 (usable)
>> >
>> > into this:
>> >
>> > reg00: base=0xc0000000 (3072MB), size=1024MB: uncachable, count=1
>> > reg01: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1
>> > reg02: base=0x100000000 (4096MB), size=1024MB: write-back, count=1
>> > reg03: base=0xbf700000 (3063MB), size= 1MB: uncachable, count=1
>> > reg04: base=0xbf800000 (3064MB), size= 8MB: uncachable, count=1
>> >
>> > which screws up the X server's attempt to map the video memory at
>> > 0xd0000000.
>>
>> I see that on my box with ASUS P5E-VM DO and 4G RAM.
>> It has an Q35 intel chipset and the intel card is set to use 256MB in BIOS.
>>
>> I tested 2.6.{24*,25,25-next,25-latest-git} 32/64 bit.
>>
>> Also I get the mtrr type mismatch message on 32 and 64 bit kernels.
>>
>> ...
>>
>> [ 0.000000] BIOS-provided physical RAM map:
>> [ 0.000000] BIOS-e820: 0000000000000000 - 000000000009ec00 (usable)
>> [ 0.000000] BIOS-e820: 000000000009ec00 - 00000000000a0000 (reserved)
>> [ 0.000000] BIOS-e820: 00000000000e4000 - 0000000000100000 (reserved)
>> [ 0.000000] BIOS-e820: 0000000000100000 - 00000000cf550000 (usable)
>> [ 0.000000] BIOS-e820: 00000000cf550000 - 00000000cf55e000 (ACPI data)
>> [ 0.000000] BIOS-e820: 00000000cf55e000 - 00000000cf5e0000 (ACPI NVS)
>> [ 0.000000] BIOS-e820: 00000000cf5e0000 - 00000000cf600000 (reserved)
>>
>> [ 0.000000] BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
>> [ 0.000000] BIOS-e820: 00000000ffc00000 - 0000000100000000 (reserved)
>> [ 0.000000] BIOS-e820: 0000000100000000 - 000000012c000000 (usable)
>> ...
>>
>> cat /proc/mtrr :
>>
>> reg00: base=0xd0000000 (3328MB), size= 256MB: uncachable, count=1
>> reg01: base=0xe0000000 (3584MB), size= 512MB: uncachable, count=1
>> reg02: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1
>> reg03: base=0x100000000 (4096MB), size= 512MB: write-back, count=1
>> reg04: base=0x120000000 (4608MB), size= 128MB: write-back, count=1
>> reg05: base=0x128000000 (4736MB), size= 64MB: write-back, count=1
>> reg06: base=0xcf600000 (3318MB), size= 2MB: uncachable, count=1
>
> please try the patch at
>
> http://lkml.org/lkml/2008/4/28/52
>
> with mtrr_chunk_size=1g

Hi,

With mtrr_chunk_size=1g my box won't boot :( ( just tested 64bit kernel ).

It does without but I get a warning:

...


[ 0.000000] BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: 0000000000000000 - 000000000009cc00 (usable)
[ 0.000000] BIOS-e820: 000000000009cc00 - 00000000000a0000 (reserved)
[ 0.000000] BIOS-e820: 00000000000e4000 - 0000000000100000 (reserved)
[ 0.000000] BIOS-e820: 0000000000100000 - 00000000cf550000 (usable)
[ 0.000000] BIOS-e820: 00000000cf550000 - 00000000cf55e000 (ACPI data)
[ 0.000000] BIOS-e820: 00000000cf55e000 - 00000000cf5e0000 (ACPI NVS)
[ 0.000000] BIOS-e820: 00000000cf5e0000 - 00000000cf600000 (reserved)
[ 0.000000] BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
[ 0.000000] BIOS-e820: 00000000ffc00000 - 0000000100000000 (reserved)
[ 0.000000] BIOS-e820: 0000000100000000 - 000000012c000000 (usable)
[ 0.000000] Entering add_active_range(0, 0, 156) 0 entries of 256 used
[ 0.000000] Entering add_active_range(0, 256, 849232) 1 entries of 256 used
[ 0.000000] Entering add_active_range(0, 1048576, 1228800) 2 entries of 256 used
[ 0.000000] max_pfn_mapped = 1228800
[ 0.000000] x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
[ 0.000000] After WB checking
[ 0.000000] MTRR MAP PFN: 0000000000000000 - 0000000000100000
[ 0.000000] MTRR MAP PFN: 0000000000100000 - 0000000000120000
[ 0.000000] MTRR MAP PFN: 0000000000120000 - 0000000000128000
[ 0.000000] MTRR MAP PFN: 0000000000128000 - 000000000012c000
[ 0.000000] After UC checking
[ 0.000000] MTRR MAP PFN: 0000000000000000 - 00000000000cf600
[ 0.000000] MTRR MAP PFN: 0000000000100001 - 0000000000120000
[ 0.000000] MTRR MAP PFN: 0000000000120000 - 0000000000128000
[ 0.000000] MTRR MAP PFN: 0000000000128000 - 000000000012c000
[ 0.000000] MTRR MAP PFN: 00000000000cf801 - 00000000000d0000
[ 0.000000] After sorting
[ 0.000000] MTRR MAP PFN: 0000000000000000 - 00000000000cf600
[ 0.000000] MTRR MAP PFN: 00000000000cf801 - 00000000000d0000
[ 0.000000] MTRR MAP PFN: 0000000000100001 - 0000000000120000
[ 0.000000] MTRR MAP PFN: 0000000000120000 - 0000000000128000
[ 0.000000] MTRR MAP PFN: 0000000000128000 - 000000000012c000
[ 0.000000] rangeX: 0000000000000000 - 00000000d0000000
[ 0.000000] Setting variable MTRR 0, base: 0MB, range: 2048MB, type WB
[ 0.000000] Setting variable MTRR 1, base: 2048MB, range: 1024MB, type WB
[ 0.000000] Setting variable MTRR 2, base: 3072MB, range: 256MB, type WB
[ 0.000000] range0: 00000000cf801000 - 00000000cf801000
[ 0.000000] range: 00000000cf801000 - 00000000d0000000
[ 0.000000] Setting variable MTRR 3, base: 3320MB, range: 0MB, type WB
[ 0.000000] Setting variable MTRR 4, base: 3320MB, range: 0MB, type WB
[ 0.000000] Setting variable MTRR 5, base: 3320MB, range: 0MB, type WB
[ 0.000000] Setting variable MTRR 6, base: 3320MB, range: 0MB, type WB
[ 0.000000] Setting variable MTRR 7, base: 3320MB, range: 0MB, type WB
[ 0.000000] range0: 0000000100001000 - 0000000110001000
[ 0.000000] range: 0000000110001000 - 0000000120001000
[ 0.000000] hole: 0000000120000000 - 0000000120001000
[ 0.000000] DONE variable MTRRs
[ 0.000000] x86 PAT enabled: cpu 0, old 0x7010600070106, new 0x7010600070106
[ 0.000000] WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 1472MB of RAM.
[ 0.000000] ------------[ cut here ]------------
[ 0.000000] WARNING: at arch/x86/kernel/cpu/mtrr/main.c:1049 mtrr_trim_uncached_memory+0x154/0x18d()
[ 0.000000] Modules linked in:
[ 0.000000] Pid: 0, comm: swapper Not tainted 2.6.25-05561-g064922a-dirty #797
[ 0.000000]
[ 0.000000] Call Trace:
[ 0.000000] [<ffffffff802374f4>] warn_on_slowpath+0x64/0xb0
[ 0.000000] [<ffffffff8074ac5b>] mtrr_trim_uncached_memory+0x154/0x18d
[ 0.000000] [<ffffffff80747a08>] setup_arch+0x356/0x599
[ 0.000000] [<ffffffff80740b6f>] start_kernel+0x5c/0x3b9
[ 0.000000] [<ffffffff80740425>] x86_64_start_kernel+0x225/0x270
[ 0.000000]
[ 0.000000] ---[ end trace ca143223eefdc828 ]---
[ 0.000000] update e820 for mtrr
[ 0.000000] modified physical RAM map:
[ 0.000000] modified: 0000000000000000 - 000000000009cc00 (usable)
[ 0.000000] modified: 000000000009cc00 - 00000000000a0000 (reserved)
[ 0.000000] modified: 00000000000e4000 - 0000000000100000 (reserved)
[ 0.000000] modified: 0000000000100000 - 00000000cf550000 (usable)
[ 0.000000] modified: 00000000cf550000 - 00000000cf55e000 (ACPI data)
[ 0.000000] modified: 00000000cf55e000 - 00000000cf5e0000 (ACPI NVS)
[ 0.000000] modified: 00000000cf5e0000 - 00000000cf600000 (reserved)
[ 0.000000] modified: 00000000fee00000 - 00000000fee01000 (reserved)
[ 0.000000] modified: 00000000ffc00000 - 000000012c000000 (reserved)
[ 0.000000] Entering add_active_range(0, 0, 156) 3 entries of 256 used
[ 0.000000] Entering add_active_range(0, 256, 849232) 3 entries of 256 used
[ 0.000000] max_pfn_mapped = 1228800
[ 0.000000] init_memory_mapping

...


--($:~)-- cat /proc/mtrr
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=0xcf801000 (3320MB), size= 4KB: write-back, count=1
reg04: base=0xcf802000 (3320MB), size= 8KB: write-back, count=1
reg05: base=0xcf804000 (3320MB), size= 16KB: write-back, count=1
reg06: base=0xcf808000 (3320MB), size= 32KB: write-back, count=1
reg07: base=0xcf810000 (3320MB), size= 64KB: write-back, count=1

--($:~)-- uname -a
Linux thor 2.6.25-05561-g064922a-dirty #797 SMP PREEMPT Mon Apr 28 10:30:06 CEST 2008 x86_64 GNU/Linux

Full dmesg can be found there :


http://frugalware.org/~crazy/mtrr/mtrr_dmesg


>
> YH
>

Gabriel
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