linux-kernel - Re: [Xen-devel] [PATCH V3 8/8] xen: Speed up set_phys_to

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Date:	Tue, 11 Nov 2014 17:48:44 +0000
From:	David Vrabel <david.vrabel@...rix.com>
To:	Juergen Gross <jgross@...e.com>, <linux-kernel@...r.kernel.org>,
	<xen-devel@...ts.xensource.com>, <konrad.wilk@...cle.com>,
	<david.vrabel@...rix.com>, <boris.ostrovsky@...cle.com>,
	<x86@...nel.org>, <tglx@...utronix.de>, <mingo@...hat.com>,
	<hpa@...or.com>
Subject: Re: [Xen-devel] [PATCH V3 8/8] xen: Speed up set_phys_to_machine()
 by using read-only mappings

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@...rix.com>

David
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