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Mon, 5 Dec 2022 23:08:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D54E3C433B5; Mon, 5 Dec 2022 23:08:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670281722; bh=r1rD9KyNMBqJg8aGe8o3Z8JXG+myDQ882BtgLSHPqNo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TpC/jo3FRVmu71R9MEs5kfN81AQUSgkCo1RtoY8sR8M5AhiTlSFop6eidAkEL500R 3WWeMUWcyVAticHGeqK/2aoP8zJ2gfXDWFu0DRK+hzXV2/39r+iQZYfw63lsFkytSN wOQZ5WYoYuankdXi/+EmB2YQYxAiySX71ZEFP5fi870/7LjhHr9MA18flwOrJ3jfAU deKq/xJ+DW/jCprrJLiuNPeBq/OuVw/y5UTtOZ6Q2bVccJDKKRGeXg5n55Rl2VfBSN 6Vb0MObMeDp4t09OaVDRWiRflX+wMpfxXXb6pqRqdmoXfABnsVMwFcPmCptnviYamo +bBIg9JrEMXgQ== From: SeongJae Park To: Andrew Morton , Jonathan Corbet Cc: damon@lists.linux.dev, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, SeongJae Park Subject: [PATCH 10/11] Docs/admin-guide/mm/damon/usage: document DAMOS filters of sysfs Date: Mon, 5 Dec 2022 23:08:29 +0000 Message-Id: <20221205230830.144349-11-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221205230830.144349-1-sj@kernel.org> References: <20221205230830.144349-1-sj@kernel.org> MIME-Version: 1.0 X-Spamd-Result: default: False [-2.90 / 9.00]; 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Signed-off-by: SeongJae Park --- Documentation/admin-guide/mm/damon/usage.rst | 48 +++++++++++++++++++- 1 file changed, 46 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index 1a5b6b71efa1..3d82ca6a17ff 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -87,6 +87,8 @@ comma (","). :: │ │ │ │ │ │ │ quotas/ms,bytes,reset_interval_ms │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil │ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low + │ │ │ │ │ │ │ filters/nr_filters + │ │ │ │ │ │ │ │ 0/type,matching,memcg_id │ │ │ │ │ │ │ stats/nr_tried,sz_tried,nr_applied,sz_applied,qt_exceeds │ │ │ │ │ │ │ tried_regions/ │ │ │ │ │ │ │ │ 0/start,end,nr_accesses,age @@ -151,6 +153,8 @@ number (``N``) to the file creates the number of child directories named as moment, only one context per kdamond is supported, so only ``0`` or ``1`` can be written to the file. +.. _sysfs_contexts: + contexts// ------------- @@ -268,8 +272,8 @@ schemes// ------------ In each scheme directory, five directories (``access_pattern``, ``quotas``, -``watermarks``, ``stats``, and ``tried_regions``) and one file (``action``) -exist. +``watermarks``, ``filters``, ``stats``, and ``tried_regions``) and one file +(``action``) exist. The ``action`` file is for setting and getting what action you want to apply to memory regions having specific access pattern of the interest. The keywords @@ -347,6 +351,46 @@ as below. The ``interval`` should written in microseconds unit. +schemes//filters/ +-------------------- + +Users could know something more than the kernel for specific types of memory. +In the case, users could do their own management for the memory and hence +doesn't want DAMOS bothers that. Users could limit DAMOS by setting the access +pattern of the scheme and/or the monitoring regions for the purpose, but that +can be inefficient in some cases. In such cases, users could set non-access +pattern driven filters using files in this directory. + +In the beginning, this directory has only one file, ``nr_filters``. Writing a +number (``N``) to the file creates the number of child directories named ``0`` +to ``N-1``. Each directory represents each filter. The filters are evaluated +in the numeric order. + +Each filter directory contains three files, namely ``type``, ``matcing``, and +``memcg_path``. You can write one of two special keywords, ``anon`` for +anonymous pages, or ``memcg`` for specific memory cgroup filtering. In case of +the memory cgroup filtering, you can specify the memory cgroup of the interest +by writing the path of the memory cgroup from the cgroups mount point to +``memcg_path`` file. You can write ``Y`` or ``N`` to ``matching`` file to +filter out pages that does or does not match to the type, respectively. Then, +the scheme's action will not be applied to the pages that specified to be +filtered out. + +For example, below restricts a DAMOS action to be applied to only non-anonymous +pages of all memory cgroups except ``/having_care_already``.:: + + # echo 2 > nr_filters + # # filter out anonymous pages + echo anon > 0/type + echo Y > 0/matching + # # further filter out all cgroups except one at '/having_care_already' + echo memcg > 1/type + echo /having_care_already > 1/memcg_path + echo N > 1/matching + +Note that filters could be ignored depend on the running DAMON operations set +`implementation `. + .. _sysfs_schemes_stats: schemes//stats/