4.12-rc ppc64 4k-page needs costly allocations

[Hugh Dickins]

On Thu, 1 Jun 2017, Christoph Lameter wrote:
> 
> Ok so debugging was off but the slab cache has a ctor callback which
> mandates that the free pointer cannot use the free object space when
> the object is not in use. Thus the size of the object must be increased to
> accomodate the freepointer.

Thanks a lot for working that out.  Makes sense, fully understood now,
nothing to worry about (though makes one wonder whether it's efficient
to use ctors on high-alignment caches; or whether an internal "zero-me"
ctor would be useful).

Hugh