Re: [RFC] hugetlb reservations -- MAP_PRIVATE fixes for split vmas

[Jon Tollefson <kniht-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>]

Andy Whitcroft wrote:
> As reported by Adam Litke and Jon Tollefson one of the libhugetlbfs
> regression tests triggers a negative overall reservation count.  When
> this occurs where there is no dynamic pool enabled tests will fail.
>
> Following this email are two patches to fix this issue:
>
> hugetlb reservations: move region tracking earlier -- simply moves the
>   region tracking code earlier so we do not have to supply prototypes, and
>
> hugetlb reservations: fix hugetlb MAP_PRIVATE reservations across vma
>   splits -- which moves us to tracking the consumed reservation so that
>   we can correctly calculate the remaining reservations at vma close time.
>
> This stack is against the top of v2.6.25-rc6-mm3, should this solution
> prove acceptable it would probabally need porting below Nicks multiple
> hugepage size patches and those updated; if so I would be happy to do
> that too.
>
> Jon could you have a test on this and see if it works out for you.
>
> -apw
>   
Looking good so far.
I am not seeing any of the tests push the reservation number negative -
with this patch set applied

Jon