mm-damon-core-charge-only-the-part-of-a-region-the-filter-left.patch removed from -mm tree

The quilt patch titled
Subject: mm/damon/core: charge only the part of a region the filter left
has been removed from the -mm tree. Its filename was
mm-damon-core-charge-only-the-part-of-a-region-the-filter-left.patch

This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Donggeun Yoo <[email protected]>
Subject: mm/damon/core: charge only the part of a region the filter left
Date: Mon, 21 Sep 2026 08:24:41 -0700

Patch series "mm/damon/core: fix the size charged for a filter-trimmed region", v2.

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.

This patch (of 2):

An address range DAMOS filter that partially overlaps a monitoring region splits the region at the filter boundary, so the scheme action is applied to only one side of it. damos_apply_scheme() reads the region size once on entry, before damos_core_filter_out() performs that split.

The quota charge and the statistics update therefore account for the region as it was before the trim. schemes/<S>/stats/sz_tried counts memory the filter excluded, which Documentation/mm/damon/design.rst says is not counted as tried, and with quotas/bytes set the excluded part is charged against the budget, throttling the scheme to a fraction of what was configured.

User impact is that DAMOS could unexpectedly slowly run, due to over-charged quota. DAMOS stat could also be confusing. No critical events such as crashes or leask happen.

Re-read the region size after the core filters have run.

---

 mm/damon/core.c |    1 +
 1 file changed, 1 insertion(+)

@@ -2784,6 +2784,7 @@ static void damos_apply_scheme(struct da
 		}
 		if (damos_core_filter_out(c, t, r, s))
 			return;
+		sz = damon_sz_region(r);
 		ktime_get_coarse_ts64(&begin);
 		trace_damos_before_apply(cidx, sidx, tidx, r, nr_accesses,
 				damon_nr_regions(t), do_trace);

_

Patches currently in -mm which might be from [email protected] are

userfaultfd-clear-the-inherited-uffd-bit-in-move_swap_pte.patch mm-damon-core-prevent-size-quota-overflow-in-the-temporal-goal-tuner.patch mm-damon-tests-core-kunit-test-the-temporal-tuners-size-quota-conversion.patch