Re: [Xen-devel] [PATCH V3 8/8] xen: Speed up set_phys_to_machine() by using read-only mappings

From: David Vrabel
Date: Tue Nov 11 2014 - 12:48:53 EST


On 11/11/14 05:43, Juergen Gross wrote:
> Instead of checking at each call of set_phys_to_machine() whether a
> new p2m page has to be allocated due to writing an entry in a large
> invalid or identity area, just map those areas read only and react
> to a page fault on write by allocating the new page.
>
> This change will make the common path with no allocation much
> faster as it only requires a single write of the new mfn instead
> of walking the address translation tables and checking for the
> special cases.

Reviewed-by: David Vrabel <david.vrabel@xxxxxxxxxx>

David
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