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b=PuffpziAWFwnPx+GwTm5I81IktL90Ytz6cqBL47N2tAApCaD1794IXBGY0MSedK1C rw9QV5bzVvjay2UlCCZh7TRIgnnQK2fbmRifTouq2ueSu7LbHv9LpVsigyUKmgTC3F 0qGGzoyErrEbYAcD9JwZvu8YzEgjED1gTzEwTy6Z6ir7jFizIMgUpQGricmQ7asNhx R1OdbxXr1HAzcDYFQi6MxHFUFU9NOfNhWKFX9qS153UpEoNweD36vEjhxg47gsv2Q8 qLDyDmf471SMXGT3UL9iSD7QkAUxAxP+hZrJyjlxHi9K4QDMODlGE91820cxFthxKP Z3YKcpdKviQJA== From: SeongJae Park To: Cc: SeongJae Park , Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 09/14] mm/damon/core: remove damon_verify_nr_regions() Date: Tue, 19 May 2026 23:28:41 -0700 Message-ID: <20260520062858.167011-10-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260520062858.167011-1-sj@kernel.org> References: <20260520062858.167011-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 7566440002 X-Stat-Signature: q543dnz9m1zr7uha8cij5f5pjchazw4r X-Rspam-User: X-HE-Tag: 1779258551-862925 X-HE-Meta: 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 cRwzbPGa N1lWfExxXSWczhoMsnSwQWRmaUCNeLweQBBUmBQrbAfqKkR/1X+FLvxUSqJ3GjMScKlX1LVM5RZhfMSKImhTcJ4I63wcuw7isBTv/qoaKNyqwmVhQOpJmvI5ebIYWmklIUWPjOR4sRJ7Vm9sScweoi4XQVIxqW6NwndSVhk+F2tnRLJz05v4ljR6yxEo3trMWd4yUIfqQuTQFqXqUOJejUdBxvTs/1wk2N9Tf7SiA44ga9l2Uz8ldmo7xOJlqAXKiS3zOp9C1GqQaFFHWHJq+4V3WTA== 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 22327a23c7e57..b2d268c4102db 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