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Re: [Xen-devel] Regarding page table management changes from Xen v1 to X

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] Regarding page table management changes from Xen v1 to Xen v2 (and v3)
From: Himanshu Raj <rhim@xxxxxxxxxxxxx>
Date: Wed, 26 Apr 2006 13:56:48 -0400
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Thanks Keir for your prompt reply. 

In another example, mmapped access to a file, the new approach will incur these
two extra faults for every page fault required to bring a file page to page 

Could you tell me another example other than fork when one can use batched PTE

Thanks and best regards,

On Wed, Apr 26, 2006 at 06:44:24PM +0100, Keir Fraser wrote:
> On 26 Apr 2006, at 18:40, Himanshu Raj wrote:
> >Although, same results can be obtained by doing the v1.2 way, i.e. 
> >making one
> >hypercall requesting these 1024 changes, no?
> >
> >-Himanshu
> You have to marshal/unmarshal the batched arguments, and insert flushes 
> all over the place to ensure the requests get flushed before Linux next 
> tries to read any of the ptes. So the new method is fewer changes to 
> the guest and no slower for reasonable-sized batches.
>  -- Keir

Himanshu Raj
PhD Student, GaTech (www.cc.gatech.edu/~rhim)
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