Re: [Xen-devel] [PATCH] x86: simplify page reference handling for partially (in-)validated pages

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 3/11/08 07:42, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:

> As suggested by Keir, simplify general page reference management for
> preempted (partiall [in-]validated) pages: Reserve on reference that
> can be acquired without the risk of overflowing the reference count,
> thus allowing to have a simplified get_page() equivalent that cannot
> fail (but must be used with care).
> 
> Doing this conversion pointed out a latent issue in the changes done
> previously in this area: The extra reference must be acquired before
> the 'normal' reference gets dropped, so the patch fixes this at once
> in both the alloc_page_type() and free_page_type() paths (it's really
> only the latter that failed to work with the change described above).

Yes, that makes the *_page_type() functions quite a bit clearer. Thanks!

 -- Keir



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