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b=nmhtcTjntOUk+GVd/GfKi40OpFXwJThGcv2dCmao/FoMUpdHYTbjgQuae+KDJgvsA 77ud0y9bYni6U61DzFx18SC7GA8e/ky8Oh5UxIKc3BxAIkCmrJNm7dlubHHrhngVih s9IlZ3GcPv765b5zQTMU9rWRamkTWFsc5/RE+EmiVfRhJoT44W+10eqhIPw8z4AQLa GKyHDB8CgjWrlLnto5JKzpONAw/WOI+v2SZ7oCa2pXEIVjStFMS644HFtrQzUVCtZk DVMRxlQ9DRh79hiqK4sA4/R9D/dMBiBjgNJhiY556tKOw8JZYjIKyTQDmtc82fCdKd luiK0uUG7Rgyw== From: SeongJae Park To: Cc: SeongJae Park , Andrew Morton , Brendan Higgins , David Gow , damon@lists.linux.dev, kunit-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v1.2 03/11] mm/damon/tests/core-kunit: test damon_rand() Date: Thu, 25 Jun 2026 07:23:48 -0700 Message-ID: <20260625142357.103500-4-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260625142357.103500-1-sj@kernel.org> References: <20260625142357.103500-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Stat-Signature: cagaobj6wmyifqz5cc3rz99x5ahhhu4g X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 22CD9160012 X-HE-Tag: 1782397482-838168 X-HE-Meta: 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 UyHYhelv AJmVPSYGAncUOos8ps80fRw9ZXjkCyp+qcejD8gWdhEHH4Jy7U6MQXVs/wNaD8+QJx0fX1gyslt3VVjdgxMp4cW4u63lvC0ZIv1vBFaVqdKPuc9jonUU2oW6OK8cvny+sZbJr3yPbxk8qyhm1bpPyBcbM+kvIiNcMik4B6tXvHhc2hk+miz1gnG/v/WzWzSYt/r9gtQSVCezsfGfyGPhfvO6zZruEoZBqtyS4GG1NLMJM3Mef0aikKA/m93lSARrn7nUUyGY3fNODy/mrai6RQD9+7w== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Commit 9012c4e647df ("mm/damon: replace damon_rand() with a per-ctx lockless PRNG") optimized DAMON for better performance. Add a kunit test for ensuring the bounds of the output. Signed-off-by: SeongJae Park --- mm/damon/tests/core-kunit.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h index 1cfb8c176b873..eec7cb325a431 100644 --- a/mm/damon/tests/core-kunit.h +++ b/mm/damon/tests/core-kunit.h @@ -1460,6 +1460,22 @@ static void damon_test_is_last_region(struct kunit *test) damon_free_target(t); } +static void damon_test_rand(struct kunit *test) +{ + struct damon_ctx ctx; + int counts[10] = {}; + int i; + + prandom_seed_state(&ctx.rnd_state, get_random_u64()); + for (i = 0; i < 10000; i++) { + unsigned long rnd = damon_rand(&ctx, 0, 10); + + KUNIT_EXPECT_GE(test, rnd, 0); + KUNIT_EXPECT_LE(test, rnd, 9); + counts[rnd]++; + } +} + static struct kunit_case damon_test_cases[] = { KUNIT_CASE(damon_test_target), KUNIT_CASE(damon_test_regions), @@ -1489,6 +1505,7 @@ static struct kunit_case damon_test_cases[] = { KUNIT_CASE(damon_test_set_filters_default_reject), KUNIT_CASE(damon_test_apply_min_nr_regions), KUNIT_CASE(damon_test_is_last_region), + KUNIT_CASE(damon_test_rand), {}, }; -- 2.47.3