mm/damon/test/core-kunit: add damon_apply_min_nr_regions() test

Add a kunit test for the functionality of damon_apply_min_nr_regions().

Link: https://lkml.kernel.org/r/20260228222831.7232-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 596f33ec2d810f5dfc80d03482cb5e34113b988c..fcc1336b234c0b2ca1c27a2050a5b164790798b9 100644 (file)
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -1239,6 +1239,57 @@ static void damon_test_set_filters_default_reject(struct kunit *test)
        damos_free_filter(target_filter);
 }
 
+static void damon_test_apply_min_nr_regions_for(struct kunit *test,
+               unsigned long sz_regions, unsigned long min_region_sz,
+               unsigned long min_nr_regions,
+               unsigned long max_region_sz_expect,
+               unsigned long nr_regions_expect)
+{
+       struct damon_ctx *ctx;
+       struct damon_target *t;
+       struct damon_region *r;
+       unsigned long max_region_size;
+
+       ctx = damon_new_ctx();
+       if (!ctx)
+               kunit_skip(test, "ctx alloc fail\n");
+       t = damon_new_target();
+       if (!t) {
+               damon_destroy_ctx(ctx);
+               kunit_skip(test, "target alloc fail\n");
+       }
+       damon_add_target(ctx, t);
+       r = damon_new_region(0, sz_regions);
+       if (!r) {
+               damon_destroy_ctx(ctx);
+               kunit_skip(test, "region alloc fail\n");
+       }
+       damon_add_region(r, t);
+
+       ctx->min_region_sz = min_region_sz;
+       ctx->attrs.min_nr_regions = min_nr_regions;
+       max_region_size = damon_apply_min_nr_regions(ctx);
+
+       KUNIT_EXPECT_EQ(test, max_region_size, max_region_sz_expect);
+       KUNIT_EXPECT_EQ(test, damon_nr_regions(t), nr_regions_expect);
+
+       damon_destroy_ctx(ctx);
+}
+
+static void damon_test_apply_min_nr_regions(struct kunit *test)
+{
+       /* common, expected setup */
+       damon_test_apply_min_nr_regions_for(test, 10, 1, 10, 1, 10);
+       /* no zero size limit */
+       damon_test_apply_min_nr_regions_for(test, 10, 1, 15, 1, 10);
+       /* max size should be aligned by min_region_sz */
+       damon_test_apply_min_nr_regions_for(test, 10, 2, 2, 6, 2);
+       /*
+        * when min_nr_regions and min_region_sz conflicts, min_region_sz wins.
+        */
+       damon_test_apply_min_nr_regions_for(test, 10, 2, 10, 2, 5);
+}
+
 static struct kunit_case damon_test_cases[] = {
        KUNIT_CASE(damon_test_target),
        KUNIT_CASE(damon_test_regions),
@@ -1265,6 +1316,7 @@ static struct kunit_case damon_test_cases[] = {
        KUNIT_CASE(damos_test_filter_out),
        KUNIT_CASE(damon_test_feed_loop_next_input),
        KUNIT_CASE(damon_test_set_filters_default_reject),
+       KUNIT_CASE(damon_test_apply_min_nr_regions),
        {},
 };