Re: BUG: using smp_processor_id() in preemptible

[Avi Kivity <avi@redhat.com>]

On 06/29/2009 01:18 PM, Johannes Berg wrote:
>>> If I boot with -m 512 I get this:
>>> root@(none):~# free
>>>                total       used       free     shared    buffers     cached
>>> Mem:        378608      25196     353412          0       1012       8692
>>> -/+ buffers/cache:      15492     363116
>>> Swap:            0          0          0
>>>
>>>
>>> so something is definitely eating a lot of memory (missing about 142M).
>>> Same guest kernel/fs in qemu gets:
>>> freeroot@(none):~# free
>>>                total       used       free     shared    buffers     cached
>>> Mem:        407080      23236     383844          0       1056       8692
>>> -/+ buffers/cache:      13488     393592
>>> Swap:            0          0          0
>>>
>>> so it's missing about 114M.
>>>
>>>        
>> I get 500MB with 2.6.31-rc1+.
>>      
>
> So even my qemu is missing a lot more than you are. But I guess my
> kernel might also be a lot larger.
>    

Aha.  Maybe paravirt patching allocates a lot of memory?  Otherwise 
there should be no difference between qemu-kvm and qemu.

Do you really have a 100MB kernel?

>> What does dmesg say about the e820 map?
>>      
>
> [    0.000000] BIOS-provided physical RAM map:
> [    0.000000]  BIOS-e820: 0000000000000000 - 000000000009f000 (usable)
> [    0.000000]  BIOS-e820: 000000000009f000 - 00000000000a0000 (reserved)
> [    0.000000]  BIOS-e820: 00000000000e8000 - 0000000000100000 (reserved)
> [    0.000000]  BIOS-e820: 0000000000100000 - 000000000fff0000 (usable)
> [    0.000000]  BIOS-e820: 000000000fff0000 - 0000000010000000 (ACPI data)
> [    0.000000]  BIOS-e820: 00000000fffbc000 - 0000000100000000 (reserved)
>    

That's only 256MB (0xfff0000).

-- 
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