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 E41462F1FC7; Sun, 12 Apr 2026 16:20:03 +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=1776010804; cv=none; b=B/0GKh6XwcHWbm9XjiRhzST3VmLBuJ77NNs6JT70VfEf8ib3gRsM6CFohIa32y0tRtxkHkOTCtbsm9aHhPnicuG8t4Jjhsj8p9pVXGmO+NGHcMZ8aPeS1cf4VSRt3f5m9egM0TUCJwCoyM8UGe4kUGvKErL4C4FlKhOFODM8ZKQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776010804; c=relaxed/simple; bh=x42u0yyujS0MNNJ5zIzlJ5WzcqjchBB5xjDhcoIlpNo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IGIeRRBGMLDNiydWs1FidVmLhVhpmghPs8TXNcNIdynojXUYti5O6Akh1C5JyG+uaN2hqVbp7F5euGUWkdTgk2fMaIPUjhcbbvSFzTNdZtdSIxbOYT79IbmztA8P9eie0bT/JnlsZG5FXMAOrU0aeadFTjLnkufbPDTSNwUg1A8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AaBgWyNs; 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="AaBgWyNs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40374C2BCB0; Sun, 12 Apr 2026 16:20:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776010803; bh=x42u0yyujS0MNNJ5zIzlJ5WzcqjchBB5xjDhcoIlpNo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AaBgWyNs0nJ4v872EAZLuHaG0uWbUqGvdCTMDz0tlV8ECu0fvS1XnSqClMa706SpE 1cR0AWCe0uig23iWzz2L20aqpH5+1z6OIbv3sfdNHaEkL/V/0R3lsWcLAq1EqLXA5x sour1JLGYxaOHd3Vd8IE23KNf7XjfXdSr7LibcwEaK2p48Aq9ZD7SER0DL14Cpz8EZ UbMq+K0aCzQGGAsvyXFP5nf3X8CjMyVMGayNQBxfo7BetPG1VGWYJpGayNfOzPbwba 6VdMzOYS9oEx9bQ4nsP/lgQ2os9Yf0XvTHymFcDpOP3Q43EhUNFoURtYTt/TUik8zP XEwX/G9+ult1A== From: SeongJae Park To: Cc: SeongJae Park , "Liam R. Howlett" , Andrew Morton , David Hildenbrand , Jonathan Corbet , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , damon@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v5.2 05/11] Docs/mm/damon/design: document fail_charge_{num,denom} Date: Sun, 12 Apr 2026 09:19:48 -0700 Message-ID: <20260412161957.82835-6-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260412161957.82835-1-sj@kernel.org> References: <20260412161957.82835-1-sj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Update DAMON design document for the DAMOS action failed region quota charge ratio. Signed-off-by: SeongJae Park --- Documentation/mm/damon/design.rst | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst index 622d24e35961e..fa7392b5a331d 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -576,6 +576,28 @@ interface `, refer to :ref:`weights ` part of the documentation. +.. _damon_design_damos_quotas_failed_memory_charging_ratio: + +Action-failed Memory Charging Ratio +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +DAMOS action to a given region can fail for some subsets of the memory of the +region. For example, if the action is ``pageout`` and the region has some +unreclaimable pages, applying the action to the pages will fail. The amount of +system resource that is taken for such failed action applications is usually +different from that for successful action applications. For such cases, users +can set different charging ratio for such failed memory. The ratio can be +specified using ``fail_charge_num`` and ``fail_charge_denom`` parameters. The +two parameters represent the numerator and denominator of the ratio. The +feature is enabled only if ``fail_charge_denom`` is not zero. + +For example, let's suppose a DAMOS action is applied to a region of 1,000 MiB +size. The action is successfully applied to only 700 MiB of the region. +``fail_charge_num`` and ``fail_charge_denom`` are set to ``1`` and ``1024``, +respectively. Then only 700 MiB and 300 KiB of size (``700 MiB + 300 MiB * 1 / +1024``) will be charged. + + .. _damon_design_damos_quotas_auto_tuning: Aim-oriented Feedback-driven Auto-tuning -- 2.47.3