Re: [PATCH v6 00/13] Add support for DAX vmemmap optimization for ppc64

On 7/26/23 12:59 AM, Andrew Morton wrote:

On Tue, 25 Jul 2023 00:37:46 +0530 "Aneesh Kumar K.V" [off-list ref] wrote:

quoted

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