[PATCH v2 0/2] mm/damon/core: fix the size charged for a filter-trimmed region

[SJ Park <sj@kernel.org>]

From: Donggeun Yoo <donggeunyoo.kernel@gmail.com>

An address range DAMOS filter that partially overlaps a monitoring region
splits it, so the scheme action reaches only one side of the boundary.
damos_apply_scheme() reads the region size before that split and never
re-reads it, so the quota charge and schemes/<S>/stats/sz_tried account for
the whole original region.

Patch 1 re-reads the size after the core filters have run.  Patch 2 adds
KUnit coverage for what the function charges and reports, for the trimmed
cases and for the cases that must not change.

Changes from v1
- v1: https://lore.kernel.org/20260917003553.2465523-1-donggeunyoo.kernel@gmail.com
- Add user impact clarification to patch 1.
- Collec R-b: from SJ.
- Rebase to the latest mm-new.

Donggeun Yoo (2):
  mm/damon/core: charge only the part of a region the filter left
  mm/damon/tests/core-kunit: test the size charged for a filter-trimmed
    region

 mm/damon/core.c             |   1 +
 mm/damon/tests/core-kunit.h | 316 ++++++++++++++++++++++++++++++++++++
 2 files changed, 317 insertions(+)


base-commit: 99528f68cc4066167e5e7135c1172be1e6315102
-- 
2.47.3