[RFC PATCH 0/5] mm/damon: introduce pgidle_set probe filter type

[SJ Park <sj@kernel.org>]

Users can do effective access monitoring with DAMON, using set_pgidle
probe prep operation and pgidle_unset allowing probe filter.  In the
setup, high probe_hits means the region was accessed frequently.  Zero
probe_hits means the region was not accessed.  The filter, however,
matches only the memory that can show the idleness.  Regions of zero
probe_hits may contain memory that was just unable to show the idleness.
On virtual address space based monitoring, for example, non-present
pages are reported as cold.  It is truly cold, but if the purpose is to
make some operations like reclaiming or compressing the data, this is
not really useful.  Introduce a new probe filter type, pgidle_set, that
confirms the page is marked as idle.  Using it instead of pgidle_unset,
users can find cold pages that can effectively be processed.

Patch 1 introduces the pgidle_set probe filter type to DAMON kernel API.
Patches 2 and 3 add support for it on physical and virtual address space
operation sets, respectively.  Patch 4 adds support for it on the DAMON
sysfs interface.  Finally, patch 5 updates the documentation for the new
filter type.

SJ Park (5):
  mm/damon/api: introduce DAMON_FILTER_TYPE_PGIDLE_SET
  mm/damon/paddr: support DAMON_FILTER_TYPE_PGIDLE_SET
  mm/damon/vaddr: support DAMON_FILTER_TYPE_PGIDLE_SET
  mm/damon/sysfs: support DAMON_FILTER_TYPE_PGIDLE_SET
  Docs/mm/damon/design: update for pgidle_set probe filter

 Documentation/mm/damon/design.rst | 3 ++-
 include/linux/damon.h             | 2 ++
 mm/damon/paddr.c                  | 6 ++++++
 mm/damon/sysfs.c                  | 4 ++++
 mm/damon/vaddr.c                  | 7 +++++++
 5 files changed, 21 insertions(+), 1 deletion(-)


base-commit: 1c9ae14f592158ed68845f7552f582545cb95c9a
-- 
2.47.3