Re: [PATCH 1/3] hugetlb: Correct page count for surplus huge pages

[Dave Hansen <haveblue@us.ibm.com>]

Mon, 2008-02-25 at 14:01 -0800, Adam Litke wrote:
> 
>         spin_lock(&hugetlb_lock);
>         if (page) {
> +               /*
> +                * This page is now managed by the hugetlb allocator and has
> +                * no current users -- reset its reference count.
> +                */
> +               set_page_count(page, 0);

So, they come out of the allocator and have a refcount of 1, and you
want them to be consistent with the other huge pages that have a count
of 0?

I'd feel a lot better about this if you did a __put_page() then a
atomic_read() or equivalent to double-check what's going on.  (I
basically suggested the same thing to Jon Tollefson on the ginormous
page stuff).  It just forces the thing to be more consistent.

It also seems a bit goofy to me to zero the refcount here, then reset it
to one later on in update_and_free_page().

I dunno.  It just seems like every time something in here gets touched,
three other things break.  Makes me nervous. :(

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