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Mon, 14 Sep 2026 08:36:26 -0700 (PDT) From: Liew Rui Yan To: SJ Park Cc: damon@lists.linux.dev, linux-mm@kvack.org Subject: [RFC/Discussion] mm/damon: Implementation for paused kdamond Date: Mon, 14 Sep 2026 23:35:10 +0800 Message-ID: <20260914153640.8481-1-aethernet65535@gmail.com> X-Mailer: git-send-email 2.55.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 622F440006 X-Rspam-User: X-Stat-Signature: urqdwpzg1n89af7xczq511dy3kmmpzge X-HE-Tag: 1789400188-980445 X-HE-Meta: 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 vXClhf2y O1Cz8DNU73qv+O/ZA5hFdDfGykIRlkrC8E+Ifb4h5oJ6GVcXuex2z3CIy3wfOLy5dQMUV3SfSE8nKKA84iQLzyzAo3cdnzBVRWzd2CQi2mZ3hB5J2sSlKshWFBqCp9LTr09ujNz5xqK8mAotIGLL4nCfjiBJYnjw1xigjw0DbQzdodHnV0Vk4gUBp1YV2iAGhm/kxxe3zHx3uimFBoJIFcToDpTo0Lh8JtchBq1gN9FZQuCbL56SynNVlJ6a0FfkKh6npJNLBAAeUOJzkohwZ3Ly2fXZSeJEfBsosSfCi37otmzA7vl58TlST24oH/c/gF2fyf8G5AIGo5LHHD16Cy+r94tN17EbA8Sb/ID8bsSxEY5pWOpT+vuZG10yMCZX0DLZrZXyJ1a6lduo1KPV4u+1Y7EdEtolLFwTvcbJ0u/C3/ORw40SsFXcdizH7lGZwO7VhVnsnuSYrZxs= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi SJ, I noticed that the current implementation for paused kdamond is periodically applies online parameter updates by kdamond_usleep(). I'd like to know if we should change it to waitqueue to achieve a lower power consumption? Previous Discussion =================== I noticed that when you introduced ctx->pause [1], Sashiko asked the same question, and your response at the time was: "sample internval is 5ms by default and recommended auto-tuning setup makes it hundreds of milliseconds. So I don't think such change is required." I'm curious that, did you think it wasn't neccessary to change it to waitqueue when it was introduced, or it wasn't neccessary to do so even after it had been introduced? Asussmption =========== This is just my assumption, not a real use case I knew: When 'pause' is set on an Android device, user might want DAMON to stop running completely when the screen is off, thereby reducing the load on the CPU without losing important information such as regions and age. The current polling may make it harder for the phone to enter idle mode, resulting in some unnecessary power consumption. However, pause feature is only present in the stable version v7.2 or higher, and since the latest Android kernel is 6.18, this highly unlikely will affect any Android users. [1] https://lore.kernel.org/damon/20260321202858.98091-1-sj@kernel.org Best regards, Rui Yan