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b=MljEHJLPdHlsbffSNnQPQqAl/ys71TtEecpF6sfGRJrYEPiXomGdTfS3q42D4sRTn VlaX6Sawr9YNeS/6jnCc1lDbUCj1dm8rt+NEr2W7/zQN0WoUX/D31yjMiIrrnVcGIz TNm1YW+rquPrFqUktF5qEoTca7UZjWIalqKArT1Usfca1FBP1wUQ8qDcnPNpkB4aKP wigTtk1u0z2M5bp3s935yV/68gr+GwcB07H2NbxCBRARW+xU9pg9p/Sl0PYMu0c6mw oLthl4minkCOPyQosegn/93FXSfId2/M08NvGpGmU1FFWE79BrfXpnTx4xVsO56Kzl U4IbFMbQsoJoQ== 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 v1.1 09/14] mm/damon/core: remove damon_verify_nr_regions() Date: Wed, 20 May 2026 20:53:43 -0700 Message-ID: <20260521035349.87565-10-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260521035349.87565-1-sj@kernel.org> References: <20260521035349.87565-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 0846840006 X-Stat-Signature: 7g8cozsuq6jaq4u4r1aijtkmamr97d1m X-HE-Tag: 1779335643-385427 X-HE-Meta: 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 r5EjFp+2 s+KEN7WUuYcCJhYguEQPHsZ48qlW3eWWA0idpDKTrLdXGwiIW7TzcwFy5F5xAbJsUUTbqgQlDuzf3VMTd6dg2myea2w+83RTFbYbOZ+Q3Z8Bg+d3rN/GbXEk1Md7dDqI0PHaTcR6kLwzQ+3d3TOgiOHPGZEbOhDqm7Y/9/Gc4X8UBa2ieR07/6+SRv07SizLSx8lZqBb/fSTSMdpMAHnv8iel/N5sCO6kVCQLm+PE4vjtMp92ZDj6KLVfU8GetyGPwWjieGdugh6WG5Wc8OuNJqKRAA== 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