Undefined symbol "min_low_pfn"

Undefined symbol "min_low_pfn"

[Anupama Chandwani]

Hi,

I see min_low_pfn as an exported symbol so I am trying to print it
from a kernel module (also of GPL license), but I am getting a
undefined reference.
I want to know what pages (page frame numbers) are used by kernel
code/data/bss etc. min_low_pfn would have told me the lowest usable
pfn.
Is there another way of getting this information? Or printing the min_low_pfn?

--
Thanks,
Anupama Chandwani

Re: Undefined symbol "min_low_pfn"

[Valdis.Kletnieks]

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On Mon, 27 Jul 2009 11:17:20 PDT, Anupama Chandwani said:

> I want to know what pages (page frame numbers) are used by kernel
> code/data/bss etc. min_low_pfn would have told me the lowest usable
> pfn.
> Is there another way of getting this information? Or printing the min_low_pfn?

What are you trying to do with that number?  Perhaps if you explain the
problem you're trying to solve by looking at min_low_pfn, somebody will have
a better solution...


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Re: Undefined symbol "min_low_pfn"

[Anupama Chandwani]

Sure,

On Mon, Jul 27, 2009 at 11:45 AM, <Valdis.Kletnieks@vt.edu> wrote:
> On Mon, 27 Jul 2009 11:17:20 PDT, Anupama Chandwani said:
>
>> I want to know what pages (page frame numbers) are used by kernel
>> code/data/bss etc. min_low_pfn would have told me the lowest usable
>> pfn.
>> Is there another way of getting this information? Or printing the min_low_pfn?
>
> What are you trying to do with that number?  Perhaps if you explain the
> problem you're trying to solve by looking at min_low_pfn, somebody will have
> a better solution...
>

I am trying to find the pfns that belong to the kernel image in RAM.
It is a study project to learn the memory management of the linux
kernel, and perhaps suggest a few optimizations.
With min_low_pfn, I can claim that all pfns under it, belong to the
kernel image and hence cannot be used by others.

I have the pfns of other pools, like mapped, mlocked, etc.

Thanks,
Anupama