On 29/10/2018 23:25, Dan Williams wrote: > I'm wondering if we're adding an explicit is_zone_device_page() check > in this path to determine the page mapping size if that can be a > replacement for the kvm_is_reserved_pfn() check. In other words, the > goal of fixing up PageReserved() was to preclude the need for DAX-page > special casing in KVM, but if we already need add some special casing > for page size determination, might as well bypass the > kvm_is_reserved_pfn() dependency as well. No, please don't. The kvm_is_reserved_pfn() check is for correctness, the page-size check is for optimization. In theory you could have a ZONE_DEVICE area that is smaller than 2MB and thus does not use huge pages. Paolo
