From nobody Sun Feb 8 06:05:44 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 E97F82EF65C; Sun, 26 Oct 2025 18:22:24 +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=1761502945; cv=none; b=Q9BpqUipz2BjI3jU0vXHFYED/whav1gEFfSd2a/z/mWBkcW5f7UCfPwUfJ7Bpmg5Z+MTiQGxdZ0Mz5VGPgr1vj4gVtqy+nKgpjkI0CtqrdLpLekOFIQHx2Zf1FiXKxwEz5jRoNhk7GmePeIh6AvjiZTvhfRKwGtmmMczCH11HnE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761502945; c=relaxed/simple; bh=6KFGqHMIsMqbpZ/3NGUtXQIvFV13533Rw2CJqlg7hEo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aE0WWVkcJOtQTQfz/6HIyY717LGdQyixy/8JFVt9YTF9apuwmBaG1q/+2ko/N9uAj/+ULWOXFdTldAw6MeQR8noKjzVlTdhocObtTmt/NNBUAv1YaXWfpU6oXxMCgsxAiZaw1Z7zrkYbnns/PNYaaMM+9Ch6+K7dcR/J4wrHaPI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RTAlIaFC; 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="RTAlIaFC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F52AC113D0; Sun, 26 Oct 2025 18:22:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761502944; bh=6KFGqHMIsMqbpZ/3NGUtXQIvFV13533Rw2CJqlg7hEo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RTAlIaFCfytgwXs9ORvXAod3Fz7oB58hyIdfeAIeJu5EwMeMSDUqlhKhIkn5ODmpD qp7P/wbYITc5L5MWvAoJnSeUPat0zM69YQPvRvVJHIh3iRW1gO8iM1jdMybEKeUtUF uaPhIU4SK+a2NMrYjjOml5gi38w+Rh3Mo5J67ZjMuwAp3STSGZdIGW96vhjbVADBKu 29sb9E46HBaFw7M9kUd+hByxhqalpWUuBNk/w85RVclxBwSAxyMml/gIWSt8AaflKf JtMnsBeUFq9z0L5nNLX7vgz0fJRbkdv6hu4qgskZXaUHt1GmXtTGBQn6NLEiUVumBt M1F+k6de/VBew== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , "Liam R. Howlett" , David Hildenbrand , Jonathan Corbet , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , Suren Baghdasaryan , Vlastimil Babka , damon@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 4/8] Docs/admin-guide/mm/damon/usage: document empty target regions commit behavior Date: Sun, 26 Oct 2025 11:22:09 -0700 Message-ID: <20251026182216.118200-5-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251026182216.118200-1-sj@kernel.org> References: <20251026182216.118200-1-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" Committing a monitoring target with empty target regions is for keeping the current monitoring results. This behavior was introduced by commit 973233600676 ("mm/damon/sysfs: update monitoring target regions for online input commit"). The behavior is not documented, though. Update the usage document for clarifying this behavior. Signed-off-by: SeongJae Park --- Documentation/admin-guide/mm/damon/usage.rst | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/a= dmin-guide/mm/damon/usage.rst index d8a3d6e740b3..9991dad60fcf 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -134,7 +134,8 @@ Users can write below commands for the kdamond to the `= `state`` file. - ``on``: Start running. - ``off``: Stop running. - ``commit``: Read the user inputs in the sysfs files except ``state`` file - again. + again. Monitoring :ref:`target region ` inputs are also = be + ignored if no target region is specified. - ``update_tuned_intervals``: Update the contents of ``sample_us`` and ``aggr_us`` files of the kdamond with the auto-tuning applied ``sampling interval`` and ``aggregation interval`` for the files. Please refer to @@ -296,6 +297,11 @@ In the beginning, this directory has only one file, ``= nr_regions``. Writing a number (``N``) to the file creates the number of child directories named `= `0`` to ``N-1``. Each directory represents each initial monitoring target regi= on. =20 +If ``nr_regions`` is zero when committing new DAMON parameters online (wri= ting +``commit`` to ``state`` file of :ref:`kdamond `), the commit +logic ignores the target regions. In other words, the current monitoring +results for the target are preserved. + .. _sysfs_region: =20 regions// --=20 2.47.3