From nobody Sun Feb 8 09:10:16 2026 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 47BDF58ABE; Mon, 19 Feb 2024 19:44:47 +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=1708371888; cv=none; b=NdWgradMnkSZpbcJ1n/LaJ8cg0viuIkhMat+PscEV7XqUEtNH5ilHmSfJYXxw0JbaqFIxthemUL5xMEiRJgTQG13eYyOAaLoC4uCph2kBd3rcOebOWIpnx6ph+sXD8bIIeBgtrLTSq/FOZP3i2G3IgDDVV+AcpVlQKo30H+YCqE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708371888; c=relaxed/simple; bh=dE+jqLZYW9QB5NiFklbDnZHaYSFDuOnT6wibaYvQ7fQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=V6CSpID45oPoL3UOUAIop8LyyzyOjdCMwgItGP8u7CaMmoh/AOBivPmYqFPOydJRZovqLJhcOuFR8Odon7OzQhsCKst0S4YELVZcGULNKASK1/ByvfMuwtSm0rYxEHou4bJVqgTLIeBhyeUnlPUyCc5REKIjnSJdgEmjQURtwgE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rN+wAd4r; 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="rN+wAd4r" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A133C43399; Mon, 19 Feb 2024 19:44:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708371887; bh=dE+jqLZYW9QB5NiFklbDnZHaYSFDuOnT6wibaYvQ7fQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rN+wAd4rUpHbmoSCSt+/pVijeH1M2J+z3ioq9IiqpMA7SQFSRjct47t4BrxCbYLzm g+NTWKrJdapNMH3m9ClPNCicsC8FXavIYUJ+PTZpM3XOUKOjufVIRPa+f6MVCL8FKx mnvvP4UR8ztDA3EZAIC758uAZSZn6xL0EAMZAUfFtGXapQSihyvtpmetzNaC/Kghcx UNloo8Ow4xzXJiJmt/6CbhAsy17pIVqzgkj0XUIKlijM/hF+Tkk2+/az2jLdwG67tG ZGw7C9Tdx2lPuF00Kfz/OfYDrG79xQFFIGBkn/Tpc1eB2mhLP1THJX3eXJLAQ/kPEA eQzcGIUVQS9rA== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , Jonathan Corbet , damon@lists.linux.dev, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 15/20] Docs/mm/damon/design: document quota goal self-tuning Date: Mon, 19 Feb 2024 11:44:26 -0800 Message-Id: <20240219194431.159606-16-sj@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240219194431.159606-1-sj@kernel.org> References: <20240219194431.159606-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" update DAMON design doc to explain the quota goal self-tuning, which can be used by setting the goal's metric to metrics that kernel can self-retrieve. Signed-off-by: SeongJae Park --- Documentation/mm/damon/design.rst | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/des= ign.rst index 2bd0c203dcfb..8c89d26f0baa 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -398,12 +398,28 @@ Aim-oriented Feedback-driven Auto-tuning ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ =20 Automatic feedback-driven quota tuning. Instead of setting the absolute q= uota -value, users can repeatedly provide numbers representing how much of their= goal -for the scheme is achieved as feedback. DAMOS then automatically tunes the +value, users can specify the metric of their interest, and what target val= ue +they want the metric value to be. DAMOS then automatically tunes the aggressiveness (the quota) of the corresponding scheme. For example, if D= AMOS is under achieving the goal, DAMOS automatically increases the quota. If = DAMOS is over achieving the goal, it decreases the quota. =20 +The goal can be specified with three parameters, namely ``target_metric``, +``target_value``, and ``current_value``. The auto-tuning mechanism tries = to +make ``current_value`` of ``target_metric`` be same to ``target_value``. +Currently, two ``target_metric`` are provided. + +- ``user_input``: User-provided value. Users could use any metric that th= ey + has interest in for the value. Use space main workload's latency or + throughput, system metrics like free memory ratio or memory pressure sta= ll + time (PSI) could be examples. Note that users should explicitly set + ``current_value`` on their own in this case. In other words, users shou= ld + repeatedly provide the feedback. +- ``some_mem_psi_us``: System-wide ``some`` memory pressure stall informat= ion + in microseconds that measured from last quota reset to next quota reset. + DAMOS does the measurement on its own, so only ``target_value`` need to = be + set by users at the initial time. In other words, DAMOS does self-feedb= ack. + =20 .. _damon_design_damos_watermarks: =20 --=20 2.39.2