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b=pmUnRFIChWDWwhJxLVO7VzYaEr21cBFNt5vFZXdhn4hObmhuEZeGNgIE2xBQtHO7Y d5ZZJ7TXwa7VPq234F5zPHdhKgUlTj0F+0IB6tVM5myIW687yeM9UYiF/m32ANpAEP i+RYt6T6RcWdWDvIexlbj83YEY+wcLLYzL3yzOtv+U3B0xbla+LlXYGAaZmdpplDyS z3qmrmg1fjO0e5X3z3s4NyZEP6dff+b6jLa6wJBKD1rm5QpzIqap+czcoXm6ESQXFa k1SFj6BWJjtYmzDUEuDMdL2RlDRBGJxjVAB8h1wYuR/HiksHxVR0twjwIrzLcIrIcj L2J4bDpA4UaYw== From: SeongJae Park To: SeongJae Park Cc: Ravi Jonnalagadda , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, akpm@linux-foundation.org, corbet@lwn.net, bijan311@gmail.com, ajayjoshi@micron.com, honggyu.kim@sk.com, yunjeong.mun@sk.com Subject: Re: [RFC PATCH v2 0/3] mm/damon: Introduce node_target_mem_bp Quota Goal Metric Date: Sat, 31 Jan 2026 11:54:07 -0800 Message-ID: <20260131195408.66514-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260130014807.51302-1-sj@kernel.org> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: e3hgq1sfzhyj4gqah1w4c5yaaystrw7x X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: D7A3F180006 X-HE-Tag: 1769889259-723205 X-HE-Meta: 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 tqrqpxn2 dIAUu9xjWaiENu+ycBX2rZnMiP6t1/nBRiJQlI7gBQy7xv96GwvLWHzvucatdOHMY1i4wkJxpfMB6amMCQeoQHvBOSVr81m8oO/jeXe1B0ohbT+xg53MOfpiidSWwmKTypWsmXdp1Tw3oapOD9JtCyot86Y4HPqSEF/s1V5vTJ3RZjI5s9Mepg46CQoS3UHqN8oIP4zB3oOt5dAE/6WXvQQuyN9aOOD2GGVVAnR4z0PvcZ/WmPEBzpLUUmLLGoCchCR+Q36cRthu8rGjITz/TC9FenpkaU+L0w3siXYe46vQbNuTngpeOD9ZTanF5TzfFklzSk/X0Txk1qXusLzxAzz7DNmvuKy9kuT/CuRdZ7SdAL6hZmhGWXrFBMQ== 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: On Thu, 29 Jan 2026 17:48:06 -0800 SeongJae Park wrote: > On Thu, 29 Jan 2026 13:58:11 -0800 Ravi Jonnalagadda wrote: > > > This series introduces a new DAMON quota goal metric, `node_target_mem_bp`, > > designed for controlling memory migration in heterogeneous memory systems > > (e.g., DRAM and CXL memory tiering). > > > > v1: https://lore.kernel.org/linux-mm/20260123045733.6954-1-ravis.opensrc@gmail.com/T/#u [...] > Context 0: monitors node 0, migrate_hot -> node 1 > goal: node_ineligible_mem_bp, nid=0, target=4000 > > Context 1: monitors node 1, migrate_hot -> node 0 > goal: node_target_mem_bp, nid=0, target=6000 In offline, Ravi enlightened me that using a single context with two schemes instead of the above two contexts setup can be more efficienct and useful. I agree that. It will be able to only single kdamond, and there could be more flexible use cases that can use the whole-memory access pattern. That is, we can use single context with the two schemes, but adding a core layer DAMOS filters for applying the schemes to only memory of node 0 and node 1, respectively. Similar for memory tiering use cases. But I was recommending the multi contexts approach to people because the current implementation of DAMOS is not efficient when both quota and core layer filters are used. I was actually working on making it improved, and just posted an RFC patch series [1]. After the patches are merged, hopefully the single context approach will be useful and effcient enough for varying use cases including the memory tiering. [1] https://lore.kernel.org/20260131194145.66286-1-sj@kernel.org Thanks, SJ [...]