Xen devel - Jun 2006 - page table walk in xen_{create, destroy}_contiguous_region

Is there a particular reason why these functions need to walk the page table
rather than doing a much cheaper p2m
translation? vstart is assumed to be in the direct mapping area anyway
(otherwise the uses of __pa() in the same
functions wouldn''t be valid).

Thanks, Jan

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On 26 Jun 2006, at 14:53, Jan Beulich wrote:
> Is there a particular reason why these functions need to walk the page 
> table rather than doing a much cheaper p2m
> translation? vstart is assumed to be in the direct mapping area anyway 
> (otherwise the uses of __pa() in the same
> functions wouldn''t be valid).
>
> Thanks, Jan
Looks like the walks are not really needed.

  -- Keir


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>> Is there a particular reason why these functions need to walk the page 
>> table rather than doing a much cheaper p2m
>> translation? vstart is assumed to be in the direct mapping area anyway 
>> (otherwise the uses of __pa() in the same
>> functions wouldn''t be valid).
>>
>> Thanks, Jan
>
>Looks like the walks are not really needed.
Subject: Replace page table walks by simple address calculation
Signed-off-by: jbeulich@novell.com 

Makes the code both smaller and faster.




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