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b=Unnq69QlXqH2oNBMdgOndbbuJ58+x6JSFqTk9uQ5zb89qOF3njkhcNNjP9kWH+4ld ER+pquzrTBUyXfL0XtbdK23k4XZTfLw24qqTlJVWB3tqgpoju6RRUjjCqibSy59Rv+ RoyH+sof7UukWsTxLUa0g7CCu7l2aq28AjIYyWoiIyI78nl0f0/Hyj0i4rYd5ytL/K DBzQhCHFIaHNo7MZgs+d5R6PTQDNd5Bh2Zn/G1sG439Lt2cAnZjXSOXc/eGI0DbhWw Pjy+kLZcHDB/+ij0Cba1zBo7wMa+UDIViAFIYfDbWPmw87NL7A/gBWJcz/wzjFkelD UIJFloVOLqhqw== From: SeongJae Park To: Liew Rui Yan Cc: SeongJae Park , linux-mm@kvack.org, damon@lists.linux.dev, linux-doc@vger.kernel.org, Andrew Morton Subject: Re: [PATCH] Docs/mm/damon: document min_nr_regions constraint and rationale Date: Fri, 20 Mar 2026 07:45:29 -0700 Message-ID: <20260320144530.91737-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260320052428.213230-1-aethernet65535@gmail.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 39D2A12000D X-Stat-Signature: 3c8fj14fwm1qhtspxrpegrmd317b34uc X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1774017934-167336 X-HE-Meta: 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 y+vfoJSF /ERx7EP5nBBLx32PjQeX9v1G09I+Yh9Y22HgwMAuCM17/IU9D7ZoIGhe2gV0L187ePi5ob7AqxMQj29jvwX/QEDX9ClHjWd0gSYncz+nUVXxq0ZJryMfaqRynGJvbVwzFY98/2QSkBJFA1pibnIgIe35SnLcm4SCULxZJA7g0SlHmRyB2dtfS/oXEJRULSE+tnRo4ToMAWD9xiKN2YSdjNLDLqTplRZI/62q3Wz8OtOqOPbuniLc7+nDrIzdNai12TkRqR70uW5Ifq9oNOeWLk/I1HudYWgYjAeZ3OVUa4QgS5Ww= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hello Liew, Thank you for this patch! On Fri, 20 Mar 2026 13:24:28 +0800 Liew Rui Yan wrote: > The current DAMON implementation requires 'min_nr_regions' to be at > least 3. However, this constraint is not explicitly documented in the > admin-guide documents, nor is its design rationale explained in the > design document. > > Add a section in design.rst to explain the rationale: the virtual > address space monitoring design needs to handle at least three regions > to accommodate two large unmapped areas. While this is specific to > 'vaddr', DAMON currently enforces it across all operation sets for > consistency. > > Also update reclaim.rst and lru_sort.rst by adding cross-references to > this constraint within their respective 'min_nr_regions' parameter > description sections, ensuring users are aware of the lower bound. > > This change is motivated from a recent discussion [1]. > > [1] https://lore.kernel.org/damon/20260319151528.86490-1-sj@kernel.org/T/#t > > Signed-off-by: Liew Rui Yan Reviewed-by: SeongJae Park Thanks, SJ [...]