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b=BrjNkbKTdGzq+yhUwe5axGBJFPzytHOMQFxyeAh0qSdkRKr0X4KexLPHlVpSXlAW1 MNDZfm/0LjewDrAXXM+OawQCbXuLMTUzYXbFUlxXgFuhjU5lIN+rbkac8HawPOJeAe j3cj2CQbZYUdrE3qihZeHzkQEu+PxWJl9+Dp8zQWJpi8QsQuvhq533W6iI7lO08wX2 QfccwoG0XrzSWFd+FaAJkRme+NbCw4B7fTLVNesAwZmN8LbMiSJmAZJZ1+xlOZNHLG ytGu37IMAkzbL2ijIsUyofz5pJyhr7k2bxsh638k6gQOXMuuKc/xoOgQeoxhDmRIwX aIWMzn5k066aA== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 4/7] mm/damon: document non-zero length damon_region assumption Date: Sat, 7 Mar 2026 11:53:52 -0800 Message-ID: <20260307195356.203753-5-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260307195356.203753-1-sj@kernel.org> References: <20260307195356.203753-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: edj3qu64piscz3x1trf5fo9myn9aibsb X-Rspamd-Server: rspam09 X-Rspam-User: X-Rspamd-Queue-Id: 466FD80004 X-HE-Tag: 1772913249-752274 X-HE-Meta: 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 ktGd3GkJ UFXjDAwUw3AWSbvZQ3538XAYBrbnBHGkmQxsP3UinOBDz0R3A52GWQweyEQF1vJnmVDdTtnwaQSOMIhSkUqQDKU1XwfMqbETpLA/8aqQ9ZID+QSE9Ef815K8Mi0TQpdv5ULyk4q6/q8wrqSPlcFKIErvdE77SrbH0dHzLgqDPp+qmloMjWj4d6LHWJahyERVu69wH5AhRIqF0BFPG7Qhvc/lgXBvghj2EYXCT/lmXR2UuK5jWriGU2wnA0fnfbRzfWqfPBqNIWoLKgPE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: DAMON regions are assumed to always be non-zero length. There was a confusion [1] about it, probably due to lack of the documentation. Document it. [1] https://lore.kernel.org/20251231070029.79682-1-sj@kernel.org/ Signed-off-by: SeongJae Park --- include/linux/damon.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/damon.h b/include/linux/damon.h index 9a88cf8d152d8..6bd71546f7b20 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -55,6 +55,8 @@ struct damon_size_range { * @list: List head for siblings. * @age: Age of this region. * + * For any use case, @ar should be non-zero positive size. + * * @nr_accesses is reset to zero for every &damon_attrs->aggr_interval and be * increased for every &damon_attrs->sample_interval if an access to the region * during the last sampling interval is found. The update of this field should -- 2.47.3