On Fri, 28 Jun 2019 10:50:31 +0530 Anshuman Khandual <anshuman.khandual@xxxxxxx> wrote: > Finishing up what the commit c2febafc67734a ("mm: convert generic code to > 5-level paging") started out while levelling up P4D huge mapping support > at par with PUD and PMD. A new arch call back arch_ioremap_p4d_supported() > is being added which just maintains status quo (P4D huge map not supported) > on x86, arm64 and powerpc. Does this have any runtime effects? If so, what are they and why? If not, what's the actual point?