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Re: [Xen-devel] page ref/type count overflows

To: "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] page ref/type count overflows
From: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Date: Mon, 26 Jan 2009 16:15:32 +0000
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>>> Keir Fraser <keir.fraser@xxxxxxxxxxxxx> 26.01.09 15:54 >>>
>On 26/01/2009 14:38, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:
>
>>> I'm having at the cmpxchg8b right now. I'll also widen the fields I guess,
>>> since that's pretty easy.
>> 
>> The count_info one only, or are you also intending to change _domain?
>> With struct page_info pretty large already, I'd want to avoid growing it
>> needlessly.
>
>I'm going to change both and do it the easy way, growing the structure from
>40 to 48 bytes. You can shrink it again with the tricks you describe if
>you're keen. I'm not sure how ugly the list stuff would end up, which would
>be my main concern, but I suppose you can hide it behind list.h-style
>macros. I don't see there's much duplication of effort to phase the work
>like this.

No word on the question regarding the below-4G restriction of the Xen heap?
Also, what's the purpose of those (_domain & 1) checks in unpickle_domptr()?

Jan


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