From: SeongJae Park Date: Wed, 29 Apr 2026 15:03:05 +0000 (-0700) Subject: Docs/admin-guide/mm/damon/usage: mark scheme filters sysfs dir as deprecated X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=7e6cc9f954aa3455cd6ef4dfcbd4102265c30884;p=thirdparty%2Flinux.git Docs/admin-guide/mm/damon/usage: mark scheme filters sysfs dir as deprecated Patch series "mm/damon/sysfs: document filters/ directory as deprecated". Commit ab71d2d30121 ("mm/damon/sysfs-schemes: let damon_sysfs_scheme_set_filters() be used for different named directories") introduced alternatives of 'filters' directory, namely core_filters/ and 'ops_filters/ directories. Now the alternatives are well stabilized and ready for all users. All filters/ directory use cases are expected to be able to be migrated to the alternatives. An LTS kernel having the alternatives, namely 6.18.y, is also released. Existence of filters/ directory is only confusing. It would be better not immediately removing the directory, though. There could be users that need time before migrating to the alternatives. There might be unexpected use cases that the alternatives cannot support. Doing the deprecation step by step across multiple years like DAMON debugfs deprecation would be safer. Start the deprecation changes by announcing the deprecation on the documents. Every year, one more action for completely removing the directory will be followed, like DAMON debugfs deprecation did. Following yearly actions are currently expected. In 2027, deprecation warning kernel messages will be printed once, for use of filters/ directory. In 2028, filters/ directory will be renamed to filters_DEPRECATED/. In 2029, filters_DEPRECATED/ directory will be removed. This patch (of 2): The alternatives of 'filters/' directory, namely 'core_filters/' and 'ops_filters/', can fully support all the features 'filters/' directory can do, and provide better user experience. Having 'filters/' directory is only confusing to users. Announce it as deprecated on the usage document. Link: https://lore.kernel.org/20260429150309.82282-1-sj@kernel.org Link: https://lore.kernel.org/20260429150309.82282-2-sj@kernel.org Signed-off-by: SeongJae Park Cc: David Hildenbrand Cc: Jonathan Corbet Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index d5548e460857..11c75a598393 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -485,10 +485,10 @@ directory can be used for installing filters regardless of their handled layers. Filters that requested by ``core_filters`` and ``ops_filters`` will be installed before those of ``filters``. All three directories have same files. -Use of ``filters`` directory can make expecting evaluation orders of given -filters with the files under directory bit confusing. Users are hence -recommended to use ``core_filters`` and ``ops_filters`` directories. The -``filters`` directory could be deprecated in future. +Use of ``filters`` directory can make filters evaluation orders confusing to +expect. For this reason, ``filters`` directory is deprecated. It is still +functioning, but is scheduled for removal in the near future. Users should use +``core_filters`` and ``ops_filters`` directories instead. In the beginning, the directory has only one file, ``nr_filters``. Writing a number (``N``) to the file creates the number of child directories named ``0``