On Wed, Feb 22, 2023 at 04:55:20PM -0700, Yu Zhao wrote:
> Currently anonymous folios only support two orders: 0 and the PMD
> order. Flexible orders for anonymous folios can resist both internal
> or external fragmentations when the PMD order is too underutilized or
> costly to allocate. Flexible orders can also leverage the TLB
> coalescing feature, .e.g., order 3 for AMD and order 4 for ARM CPUs.
>
> Discussion points:
> 1. The page fault path: determining the best order and the fallback policy.
> 2. The reclaim path: detecting the utilization and the splitting policy.
> 3. The refcount and the mapcount models, e.g., reuse the PMD-mapped
> THP model or not.
> 4. The splitting, and the collapsing if needed.
> 5. Other paths: COW, GUP, madvise(), mprotect(), page migration, etc.
6. Given the number of TLB is farrr less than the number of pages,
what workload prefers MADV_ORDER6 over MADV_HUGEPAGE for instance?
