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b=JtY5kwgF4NwiR351gN+IX2c7r/wJR+0aeF7H+sK8LicM/7/DxyiXigb0TCZ1ozEla 0RsIyyO4Lbz+bYSE71gTiHiEncqPdNwEjAwFHjE9PFGwQXfptpQx8MVzKARWNuF4j5 bUXioO3JgTlq0Qggl4aqdkeJUsipCmLdCYQHj4ztcuCwMGAMYvGS+k9HedAVX2vIkx qOG7euYJG+CuXuKHcsz+GPig1oDr2n1hMWQtC59Y1CNr0J8yBnRu1umoNlKsHJFzM/ SbfuvdcQFxDNkXl7ogp47u87t/ROI5Loqe5V7v/dmaWoOgz8drDrXyVXyc35TDD/p0 JUEYKQKQluElw== 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 v1.2 09/14] mm/damon/core: remove damon_verify_nr_regions() Date: Thu, 21 May 2026 07:34:19 -0700 Message-ID: <20260521143428.83157-10-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260521143428.83157-1-sj@kernel.org> References: <20260521143428.83157-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: A2C36A0013 X-Stat-Signature: j4op3pbpkkkirdsqdnjg1jx1uorsi5bd X-HE-Tag: 1779374081-996944 X-HE-Meta: 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 Xx99LWje eZppvlMdgt/kYde3kmj43+Z5LgV9dhJZavDQZIUF+IguKU3TPGr7j4B+hOBFFplIwnMUqW1KHx+tSx5pEjILhnYAbChv9FL2CF+nd23s7XXnAXi0gou1MN4qHHWSLAFnE9TssISuOQp219qfpLXNCTI96vasz8bsNiVplwJC/dC0w132oUSbr9JSmCQ4MGKcuJ61X4sJDNLD3UeMoKVpf4TSC+ngpdEbChjpjOWBxgZFQ6EzgR1MYsb7pWNGX9NLrYSpmGkktuihS5xvXaNiOzb4OPA== 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