Re: [PATCH v1 08/36] mm/hugetlb: check for unreasonable folio sizes when registering hstate
David Hildenbrand <[email protected]>
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On 28.08.25 16:45, Lorenzo Stoakes wrote: > On Thu, Aug 28, 2025 at 12:01:12AM +0200, David Hildenbrand wrote: >> Let's check that no hstate that corresponds to an unreasonable folio size >> is registered by an architecture. If we were to succeed registering, we >> could later try allocating an unsupported gigantic folio size. >> >> Further, let's add a BUILD_BUG_ON() for checking that HUGETLB_PAGE_ORDER >> is sane at build time. As HUGETLB_PAGE_ORDER is dynamic on powerpc, we have >> to use a BUILD_BUG_ON_INVALID() to make it compile. >> >> No existing kernel configuration should be able to trigger this check: >> either SPARSEMEM without SPARSEMEM_VMEMMAP cannot be configured or >> gigantic folios will not exceed a memory section (the case on sparse). > > I am guessing it's implicit that MAX_FOLIO_ORDER <= section size? Yes, we have a build-time bug that somewhere. -- Cheers David / dhildenb