From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6EBE551AFD2 for ; Wed, 30 Sep 2026 17:43:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790790199; cv=none; b=Cx4WsTmQcg3XXTNg+/b3IlwGO3ST6U/PnRS0D8kAD/uMEBpz59Bve4jiyPf7G5BmX3AHjXt4nzPj420z3q/Kub9SNEtWSdFEgDCyOJj4asW5rhjgRefJlVM/dcueMEvxQxd+A76di/DkSx4e61yWxfSDDk9zlB5CXO7HVwXDdiU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790790199; c=relaxed/simple; bh=8gKn6EkV4vIpOc/qmqduu9W314kO3+alMIfob4Lzf84=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Vy9eGWhhvIUhOqRBdfpfRtpkQK6HRFkAjYu2eSno7FihhtVTpgc96qOShkZkoDCyb4PzANpbVAbF/M07hXLq4qtsEMpg/urI+JzsYFkU2280ohiJR9zc7RosjXhZ6JMMx8qp3hBqyz7tt3BDbUkOYqSG4xpO8uCiI8dHSKjYm00= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cTzJiMFC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cTzJiMFC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E7C01F000FF; Wed, 30 Sep 2026 17:43:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790790198; bh=xTW9Cw+ZcS12jO83YnXP1st5xk5mD5xflpHpBRWXLhg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cTzJiMFCXlMtSVTF0o7CZqPCq72Q2YjB3KjJ8OGNYN3Np1u/OveVfqLR7fRWI41I1 wvFWMI7QpDBb0wpyDwVtuIFQkBC8G7/BqnnI1R7K2+gdgwB46T+Fp+/zZ08IML/LQj 1Y8UuTu3YZvqxfdMTHtHE8H/NW339WyAIJLWopQpHfj3qsUHulXGxwFVyQZ9dPgSpg 1ur/YQrWQIO/QRAIfrHT/BrQrvaUz3W8MQ79cqXd+cxlEACEjqQU/FuJi9kyXFusS3 EV6Q2qfS4bDniEvIMEtGAwthUZV/+pMRFJfE15mWWTvuk/6xXWZeY9tdOsm1YsErJQ NS5kQorJ018zA== From: SJ Park To: Anton Gavriliuk Cc: SJ Park , damon@lists.linux.dev Subject: Re: Memory tiering with DAMON/DAMOS auto-tuning Date: Wed, 30 Sep 2026 10:43:13 -0700 Message-ID: <20260930174314.60183-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Wed, 30 Sep 2026 19:26:31 +0300 Anton Gavriliuk wrote: > I would go back to memory tiering VCF9.1-like behavior you helped me > configure, for new few questions: > > 1. It works with the goal of 50% free memory for numa node 0, but > when I tried to set 25% free memory, it didn't do anything... > > [root@localhost ~]# COLUMNS=500 numastat -p $(pgrep valkey-server) | cat > > Per-node process memory usage (in MBs) for PID 3808 (valkey-server) > Node 0 Node 1 Node 2 > Node 3 Total > --------------- --------------- --------------- > --------------- --------------- > Huge 0.00 0.00 0.00 > 0.00 0.00 > Heap 0.11 0.00 0.00 > 0.00 0.11 > Stack 0.03 0.00 0.00 > 0.00 0.03 > Private 238356.25 2.19 3.42 > 0.00 238361.86 > ---------------- --------------- --------------- --------------- > --------------- --------------- > Total 238356.39 2.19 3.42 > 0.00 238362.00 > [root@localhost ~]# So, your workload is using ~232 GiB of node 0 memory and no demotion of it is occurred. According to your original mail [1], the node 0 has ~377 GiB memory. If we make 25% of it free, it means it should have 75% of it (~282 GiB) be utilized. If the node0 has only your workload, it means node 0 memory utilization is still only ~61%. In other words, 25% free memory goal is already achieved. Than DAMON wouldn't do any demotion. Does the theory makes sense? Maybe you can confirm by checking the free memory ratio of node 0. [...] > 2. If there are no un-accessed pages to demote for achieving a defined > goal, damon will demote pages with the most rare access ? No. Because you set '--access_rate 0% 0%' for the demotion scheme, it will do no demotion in the scenario. You could try '--access_rate 0% max' if you want. You may also need to remove '--damos_filter reject young' option from the command if that is really what you want to do. [1] https://lore.kernel.org/CAAiJnjp5F8ZuPG1gEsD_Wgs7Z+GToz67nzjr0490sz9y328=dg@mail.gmail.com Thanks, SJ [...]