On 7/26/23 12:59 AM, Andrew Morton wrote: > On Tue, 25 Jul 2023 00:37:46 +0530 "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> wrote: > >> This patch series implements changes required to support DAX vmemmap >> optimization for ppc64. > > Do we have any measurements to help us understand the magnitude > of this optimization? > > And any documentation which helps users understand whether and > why they should enable this feature? That is memory space optimization due to kernel reusing the tail page struct pages. The details of the optimization is documented in patch 11. We document there the impact with both 4k and 64K page size. -aneesh