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Howlett" , 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: [PATCH 09/12] Docs/mm/damon/design: update for max_nr_snapshots Date: Tue, 16 Dec 2025 00:01:22 -0800 Message-ID: <20251216080128.42991-10-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251216080128.42991-1-sj@kernel.org> References: <20251216080128.42991-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: C498E14000F X-Stat-Signature: i85bo73ywkyyz1wzkezy3dnxyp1u4krr X-Rspam-User: X-HE-Tag: 1765872119-952896 X-HE-Meta: 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 gEjzxdEo 4fV0V5pbvcx+0RxZDYZdb3lS1XvMuWsMIsaGpgCwIuusEsv4iQrMf8D6d33Me5aUofT4OpybQH8bXAeCf2kp4doePfYFWI9PLWTxFKdsMtFHq1pOSXjBTsKs7LXCpANk82kVxX6fyS8QI0Sf2VNzCZ1+uOoBx7YyTSOr9KNmuhlMsR3+efRpOBrmTZ4q/xjvQukmBqdHwji/tQF4Ysoo5EKJ6/IuhWRpmHD5zRTtNUPH5SWgvJ/e1bZ32vTbH3LjOsxIcf9ye+fTxR4DaH23O/ph2ig== 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: Update DAMON design document for the newly added snapshot level DAMOS deactivation feature, max_nr_snapshots. Signed-off-by: SeongJae Park --- Documentation/mm/damon/design.rst | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst index 5cc7b7d662be..7fd819b8bbf7 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -720,6 +720,7 @@ scheme's execution. - ``qt_exceeds``: Total number of times the quota of the scheme has exceeded. - ``nr_snapshots``: Total number of DAMON snapshots that the scheme is tried to be applied. +- ``max_nr_snapshots``: Upper limit of ``nr_snapshots``. "A scheme is tried to be applied to a region" means DAMOS core logic determined the region is eligible to apply the scheme's :ref:`action @@ -741,6 +742,10 @@ to exclude anonymous pages and the region has only anonymous pages, or if the action is ``pageout`` while all pages of the region are unreclaimable, applying the action to the region will fail. +Unlike normal stats, ``max_nr_snapshots`` is set by users. If it is set as +non-zero and ``nr_snapshots`` be same to or greater than ``nr_snapshots``, the +scheme is deactivated. + To know how user-space can read the stats via :ref:`DAMON sysfs interface `, refer to :ref:s`stats ` part of the documentation. -- 2.47.3