* [PATCH v2 2/2] mm/damon/tests/core-kunit: test the size charged for a filter-trimmed region
2026-09-21 15:24 [PATCH v2 0/2] mm/damon/core: fix the size charged for a filter-trimmed region SJ Park
2026-09-21 15:24 ` [PATCH v2 1/2] mm/damon/core: charge only the part of a region the filter left SJ Park
@ 2026-09-21 15:24 ` SJ Park
1 sibling, 0 replies; 3+ messages in thread
From: SJ Park @ 2026-09-21 15:24 UTC (permalink / raw)
To: Andrew Morton
Cc: Donggeun Yoo, Brendan Higgins, David Gow, SJ Park, damon,
kunit-dev, linux-kernel, linux-kselftest, linux-mm
From: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
damos_test_filter_out() checks that an address range filter splits a
region at the filter boundary, and stops there. Nothing checks what
damos_apply_scheme() then charges to the quota and reports as tried.
damos_test_apply_scheme_filtered_sz() covers the two ways such a filter
trims a region: one that starts before the filter's range, and one that
starts inside it.
damos_test_apply_scheme_filter_sz_unchanged() and
damos_test_apply_scheme_quota_sz() cover the cases whose accounting must
not change: a region wholly inside a reject range, one wholly inside an
allow range, two filters trimming in a single call, a filter type that
never splits, no filter at all, a region the quota trims, and a quota
remainder too small for one region.
Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com>
Reviewed-by: SJ Park <sj@kernel.org>
Signed-off-by: SJ Park <sj@kernel.org>
---
mm/damon/tests/core-kunit.h | 316 ++++++++++++++++++++++++++++++++++++
1 file changed, 316 insertions(+)
diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 5ff0436c5844..df84d9cc7d20 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -1706,6 +1706,319 @@ static void damos_test_filter_out(struct kunit *test)
damos_free_filter(f);
}
+static unsigned long damos_test_apply_scheme_stub(struct damon_ctx *c,
+ struct damon_target *t, struct damon_region *r,
+ struct damos *s, unsigned long *sz_filter_passed)
+{
+ return 0;
+}
+
+static void damos_test_apply_scheme_filtered_sz(struct kunit *test)
+{
+ struct damos_access_pattern pattern = {
+ .min_sz_region = 0,
+ .max_sz_region = ULONG_MAX,
+ .min_nr_accesses = 0,
+ .max_nr_accesses = UINT_MAX,
+ .min_age_region = 0,
+ .max_age_region = UINT_MAX,
+ };
+ unsigned long min_sz = DAMON_MIN_REGION_SZ;
+ struct damos_watermarks wmarks = {};
+ struct damos_quota quota = {};
+ struct damon_ctx *c;
+ struct damon_target *t;
+ struct damon_region *r;
+ struct damos_filter *f;
+ struct damos *s;
+
+ c = damon_new_ctx();
+ if (!c)
+ kunit_skip(test, "ctx alloc fail");
+ c->ops.apply_scheme = damos_test_apply_scheme_stub;
+
+ s = damon_new_scheme(&pattern, DAMOS_STAT, 0, "a, &wmarks,
+ NUMA_NO_NODE);
+ if (!s) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "scheme alloc fail");
+ }
+ damon_add_scheme(c, s);
+
+ t = damon_new_target();
+ if (!t) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "target alloc fail");
+ }
+ damon_add_target(c, t);
+
+ f = damos_new_filter(DAMOS_FILTER_TYPE_ADDR, true, false);
+ if (!f) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "filter alloc fail");
+ }
+ f->addr_range = (struct damon_addr_range){
+ .start = 2 * min_sz,
+ .end = 8 * min_sz
+ };
+ damos_add_filter(s, f);
+ damos_set_filters_default_reject(s);
+
+ /* reject filter, region starting before the range */
+ r = damon_new_region(0, 4 * min_sz);
+ if (!r) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "region alloc fail");
+ }
+ damon_add_region(r, t);
+
+ damos_apply_scheme(c, t, r, s);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 2);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 2 * min_sz);
+ KUNIT_EXPECT_EQ(test, s->stat.sz_tried, 2 * min_sz);
+
+ if (damon_nr_regions(t) != 2)
+ goto out;
+ damon_destroy_region(damon_next_region(r), t);
+ damon_destroy_region(r, t);
+ s->stat = (struct damos_stat){};
+
+ /* allow filter, region starting inside the range */
+ f->allow = true;
+ damos_set_filters_default_reject(s);
+ r = damon_new_region(2 * min_sz, 10 * min_sz);
+ if (!r) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "region alloc fail");
+ }
+ damon_add_region(r, t);
+
+ damos_apply_scheme(c, t, r, s);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 2);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 8 * min_sz);
+ KUNIT_EXPECT_EQ(test, s->stat.sz_tried, 6 * min_sz);
+
+out:
+ damon_destroy_ctx(c);
+}
+
+static void damos_test_apply_scheme_filter_sz_unchanged(struct kunit *test)
+{
+ struct damos_access_pattern pattern = {
+ .min_sz_region = 0,
+ .max_sz_region = ULONG_MAX,
+ .min_nr_accesses = 0,
+ .max_nr_accesses = UINT_MAX,
+ .min_age_region = 0,
+ .max_age_region = UINT_MAX,
+ };
+ unsigned long min_sz = DAMON_MIN_REGION_SZ;
+ struct damos_watermarks wmarks = {};
+ struct damos_quota quota = {};
+ struct damos_filter *f, *f2;
+ struct damon_ctx *c;
+ struct damon_target *t;
+ struct damon_region *r;
+ struct damos *s;
+
+ c = damon_new_ctx();
+ if (!c)
+ kunit_skip(test, "ctx alloc fail");
+ c->ops.apply_scheme = damos_test_apply_scheme_stub;
+
+ s = damon_new_scheme(&pattern, DAMOS_STAT, 0, "a, &wmarks,
+ NUMA_NO_NODE);
+ if (!s) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "scheme alloc fail");
+ }
+ damon_add_scheme(c, s);
+
+ t = damon_new_target();
+ if (!t) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "target alloc fail");
+ }
+ damon_add_target(c, t);
+
+ f = damos_new_filter(DAMOS_FILTER_TYPE_ADDR, true, false);
+ if (!f) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "filter alloc fail");
+ }
+ f->addr_range = (struct damon_addr_range){
+ .start = 2 * min_sz, .end = 8 * min_sz};
+ damos_add_filter(s, f);
+ damos_set_filters_default_reject(s);
+
+ /* wholly inside a reject range: not counted at all */
+ r = damon_new_region(4 * min_sz, 6 * min_sz);
+ if (!r) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "region alloc fail");
+ }
+ damon_add_region(r, t);
+
+ damos_apply_scheme(c, t, r, s);
+ KUNIT_EXPECT_EQ(test, s->stat.nr_tried, 0);
+ KUNIT_EXPECT_EQ(test, s->stat.sz_tried, 0);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
+
+ /* wholly inside an allow range: counted whole, not split */
+ f->allow = true;
+ damos_set_filters_default_reject(s);
+
+ damos_apply_scheme(c, t, r, s);
+ KUNIT_EXPECT_EQ(test, s->stat.sz_tried, 2 * min_sz);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
+
+ /* two filters, each trimming: the size left after both is counted */
+ damon_destroy_region(r, t);
+ s->stat = (struct damos_stat){};
+ f->allow = false;
+ f->addr_range = (struct damon_addr_range){
+ .start = 4 * min_sz, .end = 12 * min_sz};
+ f2 = damos_new_filter(DAMOS_FILTER_TYPE_ADDR, true, false);
+ if (!f2) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "filter alloc fail");
+ }
+ f2->addr_range = (struct damon_addr_range){
+ .start = 2 * min_sz, .end = 3 * min_sz};
+ damos_add_filter(s, f2);
+ damos_set_filters_default_reject(s);
+
+ r = damon_new_region(0, 8 * min_sz);
+ if (!r) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "region alloc fail");
+ }
+ damon_add_region(r, t);
+
+ damos_apply_scheme(c, t, r, s);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 3);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 2 * min_sz);
+ KUNIT_EXPECT_EQ(test, s->stat.sz_tried, 2 * min_sz);
+
+ /* a core filter that never splits: counted whole */
+ damos_destroy_filter(f2);
+ damos_destroy_filter(f);
+ f = damos_new_filter(DAMOS_FILTER_TYPE_TARGET, true, true);
+ if (!f) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "filter alloc fail");
+ }
+ f->target_idx = 0;
+ damos_add_filter(s, f);
+ damos_set_filters_default_reject(s);
+ s->stat = (struct damos_stat){};
+
+ damos_apply_scheme(c, t, r, s);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 3);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 2 * min_sz);
+ KUNIT_EXPECT_EQ(test, s->stat.sz_tried, 2 * min_sz);
+
+ damon_destroy_ctx(c);
+}
+
+static void damos_test_apply_scheme_quota_sz(struct kunit *test)
+{
+ struct damos_access_pattern pattern = {
+ .min_sz_region = 0,
+ .max_sz_region = ULONG_MAX,
+ .min_nr_accesses = 0,
+ .max_nr_accesses = UINT_MAX,
+ .min_age_region = 0,
+ .max_age_region = UINT_MAX,
+ };
+ unsigned long min_sz = DAMON_MIN_REGION_SZ;
+ struct damos_watermarks wmarks = {};
+ struct damos_quota quota = {};
+ struct damon_region *r, *next;
+ struct damon_ctx *c;
+ struct damon_target *t;
+ struct damos *s;
+
+ c = damon_new_ctx();
+ if (!c)
+ kunit_skip(test, "ctx alloc fail");
+
+ s = damon_new_scheme(&pattern, DAMOS_STAT, 0, "a, &wmarks,
+ NUMA_NO_NODE);
+ if (!s) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "scheme alloc fail");
+ }
+ damon_add_scheme(c, s);
+ damos_set_filters_default_reject(s);
+
+ t = damon_new_target();
+ if (!t) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "target alloc fail");
+ }
+ damon_add_target(c, t);
+
+ /* no apply_scheme operation: the whole region is counted */
+ r = damon_new_region(0, 4 * min_sz);
+ if (!r) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "region alloc fail");
+ }
+ damon_add_region(r, t);
+
+ damos_apply_scheme(c, t, r, s);
+ KUNIT_EXPECT_EQ(test, s->stat.sz_tried, 4 * min_sz);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
+
+ /* no filter and no quota: the whole region is counted */
+ c->ops.apply_scheme = damos_test_apply_scheme_stub;
+ s->stat = (struct damos_stat){};
+
+ damos_apply_scheme(c, t, r, s);
+ KUNIT_EXPECT_EQ(test, s->stat.sz_tried, 4 * min_sz);
+ KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 1);
+
+ /* the quota trims the region: the trimmed size is counted */
+ damon_for_each_region_safe(r, next, t)
+ damon_destroy_region(r, t);
+ s->stat = (struct damos_stat){};
+ s->quota.esz = 2 * min_sz;
+ s->quota.charged_sz = 0;
+
+ r = damon_new_region(0, 8 * min_sz);
+ if (!r) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "region alloc fail");
+ }
+ damon_add_region(r, t);
+
+ damos_apply_scheme(c, t, r, s);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 2 * min_sz);
+ KUNIT_EXPECT_EQ(test, s->stat.sz_tried, 2 * min_sz);
+
+ /* quota remainder below one region: tried, but nothing counted */
+ damon_for_each_region_safe(r, next, t)
+ damon_destroy_region(r, t);
+ s->stat = (struct damos_stat){};
+ s->quota.esz = 1;
+ s->quota.charged_sz = 0;
+
+ r = damon_new_region(0, 4 * min_sz);
+ if (!r) {
+ damon_destroy_ctx(c);
+ kunit_skip(test, "region alloc fail");
+ }
+ damon_add_region(r, t);
+
+ damos_apply_scheme(c, t, r, s);
+ KUNIT_EXPECT_EQ(test, s->stat.nr_tried, 1);
+ KUNIT_EXPECT_EQ(test, s->stat.sz_tried, 0);
+ KUNIT_EXPECT_EQ(test, r->ar.end, 4 * min_sz);
+
+ damon_destroy_ctx(c);
+}
+
static void damon_test_feed_loop_next_input(struct kunit *test)
{
unsigned long last_input = 900000, current_score = 200;
@@ -1959,6 +2272,9 @@ static struct kunit_case damon_test_cases[] = {
KUNIT_CASE(damon_test_commit_ctx),
KUNIT_CASE(damon_test_valid_probe_params),
KUNIT_CASE(damos_test_filter_out),
+ KUNIT_CASE(damos_test_apply_scheme_filtered_sz),
+ KUNIT_CASE(damos_test_apply_scheme_filter_sz_unchanged),
+ KUNIT_CASE(damos_test_apply_scheme_quota_sz),
KUNIT_CASE(damon_test_feed_loop_next_input),
KUNIT_CASE(damon_test_set_filters_default_reject),
KUNIT_CASE(damon_test_apply_min_nr_regions),
--
2.47.3
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