RE: [Xen-devel] Different: nr_pages vs. max_pfn

["Jayaraman, Bhaskar" <Bhaskar.Jayaraman@xxxxxxx>]

Keir, does Dom0 Linux do this for each Mini-OS instance that is spawned? If so 
then shouldn't the memory usage value in xm list for each PV guest take into 
account this additional usage of memory? i.e. 32MB + 8MB?

Bhaskar.

-----Original Message-----
From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Keir Fraser
Sent: Wednesday, November 19, 2008 3:24 PM
To: Y. D.; xen-devel
Subject: Re: [Xen-devel] Different: nr_pages vs. max_pfn

The shared_info value is set up by the guest itself during boot. It's larger
because Linux adds extra space at the end of its p2m map for backend
drivers.

 -- Keir

On 19/11/08 09:45, "Y. D." <duyuyang@xxxxxxxxx> wrote:

> Hi,
>
> In start_info, there is a field nr_pages definig how much memory is allocated
> to the domain, which is obvious.
> While in shared_info, there is a field max_pfn. I don't know why max_pfn is
> not equal to nr_pages.
> Say for 32MB memory, nr_pages = 8192, while max_pfn = 10240 (may vary?), of
> which 2048 pfn's have invalid mfn.
> Can anybody explain that why max_pfn is larger? Is it static or dynamic?
> Furture, does pfn to mfn frame mapping ever change? Hopefully not.
>
> Thanks,
> Shawn
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel



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