The patch titled
Subject: Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
has been removed from the -mm tree. Its filename was
docs-admin-guide-mm-damon-usage-update-for-kdamond_pid-and-mkrm_contexts.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: SeongJae Park <sj@xxxxxxxxxx>
Subject: Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
The DAMON debugfs usage document is missing descriptions for
'kdamond_pid', 'mk_contexts', and 'rm_contexts' debugfs files. This
commit adds those.
Link: https://lkml.kernel.org/r/20211209131806.19317-6-sj@xxxxxxxxxx
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/mm/damon/usage.rst | 52 ++++++++++++++++-
1 file changed, 49 insertions(+), 3 deletions(-)
--- a/Documentation/admin-guide/mm/damon/usage.rst~docs-admin-guide-mm-damon-usage-update-for-kdamond_pid-and-mkrm_contexts
+++ a/Documentation/admin-guide/mm/damon/usage.rst
@@ -38,9 +38,9 @@ DAMON provides below three interfaces fo
debugfs Interface
=================
-DAMON exports five files, ``attrs``, ``target_ids``, ``init_regions``,
-``schemes`` and ``monitor_on`` under its debugfs directory,
-``<debugfs>/damon/``.
+DAMON exports eight files, ``attrs``, ``target_ids``, ``init_regions``,
+``schemes``, ``monitor_on``, ``kdamond_pid``, ``mk_contexts`` and
+``rm_contexts`` under its debugfs directory, ``<debugfs>/damon/``.
Attributes
@@ -273,6 +273,52 @@ the monitoring is turned on. If you wri
an error code such as ``-EBUSY`` will be returned.
+Monitoring Thread PID
+---------------------
+
+DAMON does requested monitoring with a kernel thread called ``kdamond``. You
+can get the pid of the thread by reading the ``kdamond_pid`` file. When the
+monitoring is turned off, reading the file returns ``none``. ::
+
+ # cd <debugfs>/damon
+ # cat monitor_on
+ off
+ # cat kdamond_pid
+ none
+ # echo on > monitor_on
+ # cat kdamond_pid
+ 18594
+
+
+Using Multiple Monitoring Threads
+---------------------------------
+
+One ``kdamond`` thread is created for each monitoring context. You can create
+and remove monitoring contexts for multiple ``kdamond`` required use case using
+the ``mk_contexts`` and ``rm_contexts`` files.
+
+Writing the name of the new context to the ``mk_contexts`` file creates a
+directory of the name on the DAMON debugfs directory. The directory will have
+DAMON debugfs files for the context. ::
+
+ # cd <debugfs>/damon
+ # ls foo
+ # ls: cannot access 'foo': No such file or directory
+ # echo foo > mk_contexts
+ # ls foo
+ # attrs init_regions kdamond_pid schemes target_ids
+
+If the context is not needed anymore, you can remove it and the corresponding
+directory by putting the name of the context to the ``rm_contexts`` file. ::
+
+ # echo foo > rm_contexts
+ # ls foo
+ # ls: cannot access 'foo': No such file or directory
+
+Note that ``mk_contexts``, ``rm_contexts``, and ``monitor_on`` files are in the
+root directory only.
+
+
.. _tracepoint:
Tracepoint for Monitoring Results
_
Patches currently in -mm which might be from sj@xxxxxxxxxx are
