[PATCH 0/8] mm/damon: trivial fixups

[PATCH 0/8] mm/damon: trivial fixups

[SeongJae Park]

This patchset contains patches for trivial fixups of DAMON's
documentation, MAINTAINERS section, and selftests.

SeongJae Park (8):
  mm/damon/core: update kernel-doc comments for DAMOS action supports of
    each DAMON operations set
  mm/damon/core: update kernel-doc comments for DAMOS filters supports
    of each DAMON operations set
  Docs/mm/damon/index: mention DAMOS on the intro
  Docs/admin-guide/mm/damon/usage: update DAMOS actions/filters supports
    of each DAMON operations set
  Docs/mm/damon: add a maintainer-profile for DAMON
  MAINTAINERS/DAMON: link maintainer profile, git trees, and website
  selftests/damon/sysfs: hide expected write failures
  selftests/damon/debugfs_rm_non_contexts: hide expected write error
    messages

 Documentation/admin-guide/mm/damon/usage.rst  | 41 ++++++++----
 Documentation/mm/damon/index.rst              | 22 ++++---
 Documentation/mm/damon/maintainer-profile.rst | 62 +++++++++++++++++++
 MAINTAINERS                                   |  5 ++
 include/linux/damon.h                         | 11 ++++
 .../damon/debugfs_rm_non_contexts.sh          |  2 +-
 tools/testing/selftests/damon/sysfs.sh        |  2 +-
 7 files changed, 122 insertions(+), 23 deletions(-)
 create mode 100644 Documentation/mm/damon/maintainer-profile.rst

-- 
2.25.1

[PATCH 3/8] Docs/mm/damon/index: mention DAMOS on the intro

[SeongJae Park]

What DAMON aims to do is not only access monitoring but efficient and
effective access-aware system operations.  And DAMon-based Operation
Schemes (DAMOS) is the important feature of DAMON for the goal.  Make
the intro of DAMON documentation to emphasize the goal and mention
DAMOS.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/mm/damon/index.rst | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/Documentation/mm/damon/index.rst b/Documentation/mm/damon/index.rst
index 48c0bbff98b2..2983699c12ea 100644
--- a/Documentation/mm/damon/index.rst
+++ b/Documentation/mm/damon/index.rst
@@ -4,8 +4,9 @@
 DAMON: Data Access MONitor
 ==========================
 
-DAMON is a data access monitoring framework subsystem for the Linux kernel.
-The core mechanisms of DAMON (refer to :doc:`design` for the detail) make it
+DAMON is a Linux kernel subsystem that provides a framework for data access
+monitoring and the monitoring results based system operations.  The core
+monitoring mechanisms of DAMON (refer to :doc:`design` for the detail) make it
 
  - *accurate* (the monitoring output is useful enough for DRAM level memory
    management; It might not appropriate for CPU Cache levels, though),
@@ -14,12 +15,16 @@ The core mechanisms of DAMON (refer to :doc:`design` for the detail) make it
  - *scalable* (the upper-bound of the overhead is in constant range regardless
    of the size of target workloads).
 
-Using this framework, therefore, the kernel's memory management mechanisms can
-make advanced decisions.  Experimental memory management optimization works
-that incurring high data accesses monitoring overhead could implemented again.
-In user space, meanwhile, users who have some special workloads can write
-personalized applications for better understanding and optimizations of their
-workloads and systems.
+Using this framework, therefore, the kernel can operate system in an
+access-aware fashion.  Because the features are also exposed to the user space,
+users who have special information about their workloads can write personalized
+applications for better understanding and optimizations of their workloads and
+systems.
+
+For easier development of such systems, DAMON provides a feature called DAMOS
+(DAMon-based Operation Schemes) in addition to the monitoring.  Using the
+feature, DAMON users in both kernel and user spaces can do access-aware system
+operations with no code but simple configurations.
 
 .. toctree::
    :maxdepth: 2
-- 
2.25.1

[PATCH 4/8] Docs/admin-guide/mm/damon/usage: update DAMOS actions/filters supports of each DAMON operations set

[SeongJae Park]

Supports of each DAMOS action and filters are up to DAMON operations set
implementation, but it's not mentioned in detail on the documentation.
Update the information on the usage document.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/usage.rst | 41 +++++++++++++-------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index 3d82ca6a17ff..9237d6a25897 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -279,14 +279,25 @@ 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
 that can be written to and read from the file and their meaning are as below.
 
- - ``willneed``: Call ``madvise()`` for the region with ``MADV_WILLNEED``
- - ``cold``: Call ``madvise()`` for the region with ``MADV_COLD``
- - ``pageout``: Call ``madvise()`` for the region with ``MADV_PAGEOUT``
- - ``hugepage``: Call ``madvise()`` for the region with ``MADV_HUGEPAGE``
- - ``nohugepage``: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE``
+Note that support of each action depends on the running DAMON operations set
+`implementation <sysfs_contexts>`.
+
+ - ``willneed``: Call ``madvise()`` for the region with ``MADV_WILLNEED``.
+   Supported by ``vaddr`` and ``fvaddr`` operations set.
+ - ``cold``: Call ``madvise()`` for the region with ``MADV_COLD``.
+   Supported by ``vaddr`` and ``fvaddr`` operations set.
+ - ``pageout``: Call ``madvise()`` for the region with ``MADV_PAGEOUT``.
+   Supported by ``vaddr``, ``fvaddr`` and ``paddr`` operations set.
+ - ``hugepage``: Call ``madvise()`` for the region with ``MADV_HUGEPAGE``.
+   Supported by ``vaddr`` and ``fvaddr`` operations set.
+ - ``nohugepage``: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE``.
+   Supported by ``vaddr`` and ``fvaddr`` operations set.
  - ``lru_prio``: Prioritize the region on its LRU lists.
+   Supported by ``paddr`` operations set.
  - ``lru_deprio``: Deprioritize the region on its LRU lists.
- - ``stat``: Do nothing but count the statistics
+   Supported by ``paddr`` operations set.
+ - ``stat``: Do nothing but count the statistics.
+   Supported by all operations sets.
 
 schemes/<N>/access_pattern/
 ---------------------------
@@ -388,8 +399,8 @@ pages of all memory cgroups except ``/having_care_already``.::
     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_contexts>`.
+Note that filters are currently supported only when ``paddr``
+`implementation <sysfs_contexts>` is being used.
 
 .. _sysfs_schemes_stats:
 
@@ -618,11 +629,15 @@ The ``<action>`` is a predefined integer for memory management actions, which
 DAMON will apply to the regions having the target access pattern.  The
 supported numbers and their meanings are as below.
 
- - 0: Call ``madvise()`` for the region with ``MADV_WILLNEED``
- - 1: Call ``madvise()`` for the region with ``MADV_COLD``
- - 2: Call ``madvise()`` for the region with ``MADV_PAGEOUT``
- - 3: Call ``madvise()`` for the region with ``MADV_HUGEPAGE``
- - 4: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE``
+ - 0: Call ``madvise()`` for the region with ``MADV_WILLNEED``.  Ignored if
+   ``target`` is ``paddr``.
+ - 1: Call ``madvise()`` for the region with ``MADV_COLD``.  Ignored if
+   ``target`` is ``paddr``.
+ - 2: Call ``madvise()`` for the region with ``MADV_PAGEOUT``.
+ - 3: Call ``madvise()`` for the region with ``MADV_HUGEPAGE``.  Ignored if
+   ``target`` is ``paddr``.
+ - 4: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE``.  Ignored if
+   ``target`` is ``paddr``.
  - 5: Do nothing but count the statistics
 
 Quota
-- 
2.25.1

[PATCH 5/8] Docs/mm/damon: add a maintainer-profile for DAMON

[SeongJae Park]

Document the basic policies and expectations for DAMON development.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/mm/damon/index.rst              |  1 +
 Documentation/mm/damon/maintainer-profile.rst | 62 +++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 Documentation/mm/damon/maintainer-profile.rst

diff --git a/Documentation/mm/damon/index.rst b/Documentation/mm/damon/index.rst
index 2983699c12ea..5e0a50583500 100644
--- a/Documentation/mm/damon/index.rst
+++ b/Documentation/mm/damon/index.rst
@@ -32,3 +32,4 @@ operations with no code but simple configurations.
    faq
    design
    api
+   maintainer-profile
diff --git a/Documentation/mm/damon/maintainer-profile.rst b/Documentation/mm/damon/maintainer-profile.rst
new file mode 100644
index 000000000000..24a202f03de8
--- /dev/null
+++ b/Documentation/mm/damon/maintainer-profile.rst
@@ -0,0 +1,62 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+DAMON Maintainer Entry Profile
+==============================
+
+The DAMON subsystem covers the files that listed in 'DATA ACCESS MONITOR'
+section of 'MAINTAINERS' file.
+
+The mailing lists for the subsystem are damon@lists.linux.dev and
+linux-mm@kvack.org.  Patches should be made against the mm-unstable tree [1]_
+whenever possible and posted to the mailing lists.
+
+SCM Trees
+---------
+
+There are multiple Linux trees for DAMON development.  Patches under
+development or testing are queued in damon/next [2]_ by the DAMON maintainer.
+Suffieicntly reviewed patches will be queued in mm-unstable [1]_ by the memory
+management subsystem maintainer.  After more sufficient tests, the patches will
+be queued in mm-stable [3]_ , and finally pull-requested to the mainline by the
+memory management subsystem maintainer.
+
+Note again the patches for review should be made against the mm-unstable
+tree[1] whenever possible.  damon/next is only for preview of others' works in
+progress.
+
+Submit checklist addendum
+-------------------------
+
+When making DAMON changes, you should do below.
+
+- Build changes related outputs including kernel and documents.
+- Ensure the builds introduce no new errors or warnings.
+- Run and ensure no new failures for DAMON selftests [4]_ and kunittests [5]_ .
+
+Further doing below and putting the results will be helpful.
+
+- Run damon-tests/corr [6]_ for normal changes.
+- Run damon-tests/perf [7]_ for performance changes.
+
+Key cycle dates
+---------------
+
+Patches can be sent anytime.  Key cycle dates of the mm-unstable[1] and
+mm-stable[3] trees depend on the memory management subsystem maintainer.
+
+Review cadence
+--------------
+
+The DAMON maintainer does the work on the usual work hour (09:00 to 17:00,
+Mon-Fri) in PST.  The response to patches will occasionally be slow.  Do not
+hesitate to send a ping if you have not heard back within a week of sending a
+patch.
+
+
+.. [1] https://git.kernel.org/akpm/mm/h/mm-unstable
+.. [2] https://git.kernel.org/sj/h/damon/next
+.. [3] https://git.kernel.org/akpm/mm/h/mm-stable
+.. [4] https://github.com/awslabs/damon-tests/blob/master/corr/run.sh#L49
+.. [5] https://github.com/awslabs/damon-tests/blob/master/corr/tests/kunit.sh
+.. [6] https://github.com/awslabs/damon-tests/tree/master/corr
+.. [7] https://github.com/awslabs/damon-tests/tree/master/perf
-- 
2.25.1