On Thu, 30 Dec 2021 10:07:19 +0000 SeongJae Park [off-list ref] wrote:

DAMON asks each monitoring target ('struct damon_target') to have one
'unsigned long' integer called 'id', which should be unique among the
targets of same monitoring context.  Meaning of it is, however, totally
up to the monitoring primitives that registered to the monitoring
context.  For example, the virtual address spaces monitoring primitives
treats the id as a 'struct pid' pointer.

This makes the code flexible but ugly, not well-documented, and
type-unsafe[1].  Also, identification of each target can be done via its
index.  For the reason, this patchset removes the concept and uses clear
type definition.

Thanks.  This doesn't appear to be urgent, so I'll park it until after 5.17-rc1.