The 64 megs at the top

The 64 megs at the top

[Jacob Gorm Hansen]

hi,

just a thought; the 64 megs of VA that Xen uses for its own purposes, 
how much of that is actually needed when shadow page tables are disabled?

And how much physical mem is Xen currently estimated to be using?

thanks,
Jacob


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RE: The 64 megs at the top

[Ling, Xiaofeng]

Some of my understanding, For ia32,  the VA address space really used will depned on the physical memory of the machine.
Like RO_MPT(4M),  RDWR_MPT(4M), FRAMETABLE(24M) will all depend on the whole machine memory.
the MPT need 4bytes for each page, so for 256M machine memory need 1M(both va and pa)
The pfn_info struct seems 24bytes,so each 4K page will need 24bytes, 256M memory will need 6M.(Both va and pa)
The linear page table will only occupy va address space, but always the whole 4M.
For other physical memory, the xen binary is only about 300K, others are for xen heap.




Jacob Gorm Hansen <> wrote:
> hi,
> 
> just a thought; the 64 megs of VA that Xen uses for its own purposes,
> how much of that is actually needed when shadow page tables are
> disabled? 
> 
> And how much physical mem is Xen currently estimated to be using?
> 
> thanks,
> Jacob
> 
> 
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real
> users. Discover which products truly live up to the hype. Start
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> Xen-devel mailing list
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