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Howlett" , Andrew Morton , David Hildenbrand , Jonathan Corbet , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Suren Baghdasaryan , Vlastimil Babka , damon@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 4/5] Docs/mm/damon/design: document the goal-based quota tuner selections Date: Wed, 11 Feb 2026 22:23:11 -0800 Message-ID: <20260212062314.69961-5-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260212062314.69961-1-sj@kernel.org> References: <20260212062314.69961-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: tobexmcft1suurkknxyg9py93xhj4898 X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 6C6BFA0009 X-HE-Tag: 1770877409-906633 X-HE-Meta: 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 3NUNC+tU 12p7F5zyrsvNjzTodAN9dxME2qlX3IFq8QlBRajRWYZw8TjapY9NcoW9b3kAndTCyRNl3Q85YxjSFM6+ev1lIocaBDeyFSmF2OhyV2TiT7Lff7PKVqdFrJKG3hMKT/ItsKrjO4x8ZDYxgsAHHzCXAQ0KyWchRnsI254dqUFSK7G6rK7MqO7TZVQoJfYgkxL0vwu0/dZQcIquf+0Xr53/+p31ylInxaejspSb3pYKp4fk7Kjg= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Document the newly added goal-based quota tuner selection feature. Provide the list of the available tuner with descriptions of their behaviors and when those can be used. Signed-off-by: SeongJae Park --- Documentation/mm/damon/design.rst | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst index dd64f5d7f3193..28d932ceaf7ed 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -564,6 +564,18 @@ aggressiveness (the quota) of the corresponding scheme. For example, if DAMOS is under achieving the goal, DAMOS automatically increases the quota. If DAMOS is over achieving the goal, it decreases the quota. +There are two such tuning algorithms that users can select as they need. + +- ``consist``: A proportional feedback loop based algorithm. Tries to find an + optimum quota that should be consistently kept, to keep achieving the goal. + Useful for kernel-only operation on dynamic and long-running environments. + This is the default selection. If unsure, use this. +- ``temporal``: More straightforward algorithm. Tries to achieve the goal as + fast as possible, using maximum allowed quota, but only for a temporal short + time. When the quota is under-achieved, this algorithm keeps tuning quota to + a maximum allowed one. Once the quota is [over]-achieved, this sets the + quota zero. Useful for deterministic control required environments. + The goal can be specified with five parameters, namely ``target_metric``, ``target_value``, ``current_value``, ``nid`` and ``path``. The auto-tuning mechanism tries to make ``current_value`` of ``target_metric`` be same to -- 2.47.3