Re: [Xen-devel] mem_sharing: summarized problems when domain is

To:	Jui-Hao Chiang <juihaochiang@xxxxxxxxx>
Subject:	Re: [Xen-devel] mem_sharing: summarized problems when domain is dying
From:	George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Date:	Fri, 21 Jan 2011 16:41:47 +0000
Cc:	MaoXiaoyun <tinnycloud@xxxxxxxxxxx>, xen devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Tim Deegan <Tim.Deegan@xxxxxxxxxx>
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Tim / Xiaoyun, do you think something like this might work?

 -George

On Fri, Jan 21, 2011 at 4:32 PM, George Dunlap <dunlapg@xxxxxxxxx> wrote:
> [sorry, accidentally sent too early]
>
> On Fri, Jan 21, 2011 at 4:29 PM, George Dunlap <dunlapg@xxxxxxxxx> wrote:
>> I'm not sure the exact rationale behind the "cannot fail" flag; but it
>> looks like in grant_table.c, both callers of gfn_to_mfn_unshare()
>> handle the case where the returned p2m entry is just
>
> ...invalid.  I wonder if "unsharing" the page, but marking the entry
> invalid during death would help.
>
> I suppose the problem there is that if you're keeping the VM around
> but paused for analysis, you'll have holes in your address space.  But
> just returning an invalid entry to the callers who try to unshare
> pages might work.
>
>  -George
>

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Re: [Xen-devel] mem_sharing: summarized problems when domain is dying