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xen-ia64-devel

RE: [Xen-ia64-devel][PATCH][VTD] small patches for VTD

To: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
Subject: RE: [Xen-ia64-devel][PATCH][VTD] small patches for VTD
From: "Xu, Anthony" <anthony.xu@xxxxxxxxx>
Date: Wed, 22 Oct 2008 14:11:52 +0800
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Thread-topic: [Xen-ia64-devel][PATCH][VTD] small patches for VTD
Isaku Yamahata wrote:
> On Wed, Oct 22, 2008 at 01:56:05PM +0800, Xu, Anthony wrote:
>> Yes, it is not SMP-safe there is lock for p2m.
>> Modifying p2m is not a frequent operation, why not add a lock for it?
>
> It is frequent to read p2m table. So lockless approach was adopted
> for scalability.
> It doesn't make sense to lock around only writer side.
>

If only add write lock for p2m, is there any bad impact/senario?
Can you explain more details?

Thanks
Anthony

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