From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 376962D063E; Sat, 31 Jan 2026 19:54:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769889259; cv=none; b=f95hX2xnxe677cqNjfvG5BL7P1BlmJgMhpA5zn5X0pNh7rBKPIFQ/V/lt2U6JTltkohR03NO478YuciiSu5i08Rgp7IodppO4OEAvqlh3fawDO14X8SMGHJ8fE0TT/tGtys8MyFvdd7Dccmh0CIgOpm+SbLRFhe7a3NVtt+4wIM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769889259; c=relaxed/simple; bh=N8vKGMyccUxrYrqp4qY0jWMxA5NCQ/73rs9xDcCS5Y4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mA/hULdMYD7gjHs2TaxInNlkp2snC7M86O5D9Vx4HPwbgb+bn685SzTqAGs/Ho95+Dh0BKYgyNGzEbbElURY89utKTribttm7kKn7TaTZ/l1mC7Z3n0qiSNJmXc1gaf4sdlj1yrQ7ReXm/oM8gNmsTT+U+rpJ6hi+5wpri4rvLs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pmUnRFIC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pmUnRFIC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84E10C4CEF1; Sat, 31 Jan 2026 19:54:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769889258; bh=N8vKGMyccUxrYrqp4qY0jWMxA5NCQ/73rs9xDcCS5Y4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; 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: Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 [...]