On Tue, Jun 27, 2017 at 2:56 AM, Oliver O'Halloran <[email protected]> wrote:
> Currently libnvdimm uses HPAGE_SIZE as the default alignment for DAX and
> PFN devices. HPAGE_SIZE is the default hugetlbfs page size and when
> hugetlbfs is disabled it defaults to PAGE_SIZE. Given DAX has more
> in common with THP than hugetlbfs we should proably be using
> HPAGE_PMD_SIZE, but this is undefined when THP is disabled so lets just
> give it a new name.
>
> The other usage of HPAGE_SIZE in libnvdimm is when determining how large
> the altmap should be. For the reasons mentioned above it doesn't really
> make sense to use HPAGE_SIZE here either. PMD_SIZE seems to be safe to
> use in generic code and it happens to match the vmemmap allocation block
> on x86 and Power. It's still a hack, but it's a slightly nicer hack.

Looks ok, but I seem to remember some 0day kbuild robot reports the
last time I tried to use PMD_SIZE. I'll give this a spin in my tree
and see if that's the still the case or I'm mis-remembering.
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