Re: [PATCH 0/2] mm/damon: introduce DAMOS filter type for unmapped pages

From: Honggyu Kim
Date: Thu Feb 20 2025 - 02:47:02 EST


Hi SeongJae,

On 2/20/2025 7:01 AM, SeongJae Park wrote:
User decides whether their memory will be mapped or unmapped. It
implies that the two types of memory can have different characteristics
and management requirements. Provide the DAMON-observaibility
DAMOS-operation capability for the different types by introducing a new
DAMOS filter type for unmapped pages.

I asked it before at https://github.com/damonitor/damo/issues/13 about
monitoring unused paddr area but I see this patch series is related to
applying DAMOS action.

Regarding that, do you think we can skip those unused memory area using
this filter before applying DAMOS action?

I'm not sure if the current DAMOS tries pageout/migrate action for those
unused area because they are detected as cold area although those will
be imediately skiped inside action scheme.

Thanks,
Honggyu


Changes from RFC
(https://lore.kernel.org/20241127205624.86986-1-sj@xxxxxxxxxx)
- Rebase on latest mm-unstable
- Wordsmith commit message
- Add documentation

SeongJae Park (2):
mm/damon: implement a new DAMOS filter type for unmapped pages
Docs/mm/damon/design: document unmapped DAMOS filter type

Documentation/mm/damon/design.rst | 2 ++
include/linux/damon.h | 2 ++
mm/damon/paddr.c | 3 +++
mm/damon/sysfs-schemes.c | 1 +
4 files changed, 8 insertions(+)


base-commit: a2130e89cbd08ddb6f023b0b10eb87ebbc67add1