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

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 27/01/2009 11:22, "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx> wrote:

>> Makes page_unlock() more expensive on x64. Don't know how much that matters.
> 
> I think we could perhaps merge it into type_info and take/release it at the
> same time as get_page_type/put_page_type, to avoid extra atomic ops. I'll look
> into that.
> 
> For the cpumask, I have some ideas there too...

Jan,

I have a patch for the lock field. It doesn't work yet but I should have it
done quite soon. It cleans up various races at the same time. I will also
look into the cpumask (not so important right now, but I think it will be
quite easy to get rid of anyway).

So... For the rest I thought I would leave it in your court. Since you might
be looking into it already. :-) What I see needing still to be done:
 * Shrink list_head
 * Shrink u.inuse._domain
 * Also will need to shrink sh_page_info (currently 48 bytes). It contains a
few chain pointers which you could probably compress down like page_info's
list_head.

So, overall nothing very hard, but probably a bunch of code to have to
modify! But it should get us down to 32 bytes, I think.
 
 -- Keir



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