On Mon, 29 Jan 2024 14:42:03 -0800 Sourav Panda [off-list ref] wrote:

This patch adds two new per-node fields, namely nr_page_metadata and
nr_page_metadata_boot to /sys/devices/system/node/nodeN/vmstat and a
global PageMetadata field to /proc/meminfo. This information can be
used by users to see how much memory is being used by per-page
metadata, which can vary depending on build configuration, machine
architecture, and system use.

I'm not seeing why this is very useful.  OK, you look at it and it
tells you a number, but what action can a user take based upon that
number?

Please tell us more about the value of this, the use cases, what
prompted you to expend effort on this.