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b=PRCm+J+mZl77Sc1wSkhjFvMo6gfXN2YkuIeCJ2pHOE8X0WlwQ5pbBuOyF3jt4nZRH ben/v8RpD9Pd9a0vOPWvv/7KDogs4XMbaVgxOaUBnBEBsAYLYfxu2ZzvDwzz7gPfgB Wbemfq7GP0Zvv9mudLM58kVzCVUJrZfRXcwA+KgZCQ8VNMS6PcrhiKXoF7eEDdnZh3 KeDyvyuO1x6tv8oXAa9KaW+Ju/0vxydczqLPpjzU9kn60SWU1dqC2p1uaRNfbQG9EU Hgo8plxdJhtTC3ANO7HrR39qRyGH9uagAnkV304IxGfM7N2D6x1iSepAYmeWRyflMy p0Of15I8kFNig== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 09/14] mm/damon/core: remove damon_verify_nr_regions() Date: Fri, 22 May 2026 08:40:20 -0700 Message-ID: <20260522154026.80546-10-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260522154026.80546-1-sj@kernel.org> References: <20260522154026.80546-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: nbtd89mhjws7ebexaekhm3ezji7aqwi7 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 6241816000A X-Rspam-User: X-HE-Tag: 1779464438-430771 X-HE-Meta: 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 WnbuCF+q Y+0V3DqplDap2Rw0wvnU76kDeKm4f2qixg0bckrYKwfLZKXP9M8JlI+zI/5ugSevjP4uPdGz2FOTogx9jgHzE/NF6feiS9K+lBfyE3z9t23lY3ZmEHCO8T+BVPplvdef/7l0gq5MSSzRnXGVQ/OIvxXHY8uPHjY5Aj2ZuC6fN+LoGW1B2QNP7DCiN2N5Afb0jaecirxTMggYtVkg636O4JOaobGfgIQEOWE0S/s0uKLo8FCRQtU9MJ/821QthY0HquCGLcir8fPuOluNwCj/7d+Qf8Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: When CONFIG_DAMON_DEBUG_SANITY is enabled, damon_verify_nr_regions() is called for each damon_nr_regions() invocation. damon_veify_nr_regions() iterates all regions. damon_nr_regions() is called for each region in kdamond_reset_aggregated() and damos_apply_scheme(). Hence it imposes O(n**2) overhead where n is the number of regions. Though the verification is enabled only under DAMON_DEBUG_SANITY, which is not for production use cases, it could be too high overhead. Meanwhile, damon_verify_ctx() is doing the damon_nr_regions() test. Because damon_verify_ctx() is called for each kdamond_call(), the test coverage from damon_verify_ctx() could be sufficient. Remove damon_nr_regions() verification. Signed-off-by: SeongJae Park --- mm/damon/core.c | 19 ------------------- 1 file changed, 19 deletions(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index 9cde5b47b9585..265d51ade25bf 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -686,27 +686,8 @@ void damon_destroy_target(struct damon_target *t, struct damon_ctx *ctx) damon_free_target(t); } -#ifdef CONFIG_DAMON_DEBUG_SANITY -static void damon_verify_nr_regions(struct damon_target *t) -{ - struct damon_region *r; - unsigned int count = 0; - - damon_for_each_region(r, t) - count++; - WARN_ONCE(count != t->nr_regions, "t->nr_regions (%u) != count (%u)\n", - t->nr_regions, count); -} -#else -static void damon_verify_nr_regions(struct damon_target *t) -{ -} -#endif - unsigned int damon_nr_regions(struct damon_target *t) { - damon_verify_nr_regions(t); - return t->nr_regions; } -- 2.47.3