On Wed, Sep 17, 2025 at 12:18:39PM -0400, Pasha Tatashin wrote: > On Wed, Sep 17, 2025 at 8:22 AM Jason Gunthorpe <j...@nvidia.com> wrote: > > > > On Tue, Sep 16, 2025 at 07:50:16PM -0700, Jason Miu wrote: > > > + * kho_order_table > > > + * +-------------------------------+--------------------+ > > > + * | 0 order| 1 order| 2 order ... | HUGETLB_PAGE_ORDER | > > > + * ++------------------------------+--------------------+ > > > + * | > > > + * | > > > + * v > > > + * ++------+ > > > + * | Lv6 | kho_page_table > > > + * ++------+ > > > > I seem to remember suggesting this could be simplified without the > > special case 7h level table table for order. > > > > Encode the phys address as: > > > > (order << 51) | (phys >> (PAGE_SHIFT + order)) > > Why 51 and not 52, this limits to 63bit address space, is it not?
Yeah, might have got the math off > I like the idea, but I'm trying to find the benefits compared to the > current per-order tree approach. It is probably about half the code compared to what I see here because everything is agressively simplified. > 3. It slightly complicates the logic in the new kernel. Instead of > simply iterating a known tree for a specific order, the boot-time > walker would need to reconstruct the per-order subtrees, and walk > them. The core walker just runs over a range, it is easy to compute the range. Jason
