[PATCH 0/9] mm/damon: make DAMON debugfs interface deprecation unignorable

[PATCH 0/9] mm/damon: make DAMON debugfs interface deprecation unignorable

[SeongJae Park]

DAMON debugfs interface is deprecated in February 2023, by commit
5445fcbc4cda ("Docs/admin-guide/mm/damon/usage: add DAMON debugfs
interface deprecation notice").  Make the fact unable to be easily
ignored by removing an example usage from the document (patch 1),
renaming the config (patch 2), adding a deprecation notice file to the
debugfs directory (patches 3-5), and renaming the debugfs file that
essnetial to be used for real use of DAMON (patches 6-9).

SeongJae Park (9):
  Docs/admin-guide/mm/damon/usage: use sysfs interface for tracepoints
    example
  mm/damon: rename CONFIG_DAMON_DBGFS to DAMON_DBGFS_DEPRECATED
  mm/damon/dbgfs: implement deprecation notice file
  mm/damon/dbgfs: make debugfs interface deprecation message a macro
  Docs/admin-guide/mm/damon/usage: document 'DEPRECATED' file of DAMON
    debugfs interface
  selftets/damon: prepare for monitor_on file renaming
  mm/damon/dbgfs: rename monitor_on file to monitor_on_DEPRECATED
  Docs/admin-guide/mm/damon/usage: update for monitor_on renaming
  Docs/translations/damon/usage: update for monitor_on renaming

 Documentation/admin-guide/mm/damon/usage.rst  | 42 +++++++++++--------
 .../zh_CN/admin-guide/mm/damon/usage.rst      | 20 ++++-----
 .../zh_TW/admin-guide/mm/damon/usage.rst      | 20 ++++-----
 mm/damon/Kconfig                              |  7 +++-
 mm/damon/dbgfs.c                              | 27 +++++++++---
 .../selftests/damon/_chk_dependency.sh        | 11 ++++-
 .../selftests/damon/_debugfs_common.sh        |  7 ++++
 .../selftests/damon/debugfs_empty_targets.sh  | 12 +++++-
 8 files changed, 98 insertions(+), 48 deletions(-)


base-commit: f1ab2f51e99ffb94ce127d132b24be00dc130e6c
-- 
2.39.2

[PATCH 1/9] Docs/admin-guide/mm/damon/usage: use sysfs interface for tracepoints example

[SeongJae Park]

DAMON tracepoints example on the DAMON usage document is using DAMON
debugfs interface, which is deprecated.  Use its alternative, DAMON
sysfs interface.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/usage.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index 9d23144bf985..f2feabb4bd35 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -579,11 +579,11 @@ monitoring results recording.
 While the monitoring is turned on, you could record the tracepoint events and
 show results using tracepoint supporting tools like ``perf``.  For example::
 
-    # echo on > monitor_on
+    # echo on > kdamonds/0/state
     # perf record -e damon:damon_aggregated &
     # sleep 5
     # kill 9 $(pidof perf)
-    # echo off > monitor_on
+    # echo off > kdamonds/0/state
     # perf script
     kdamond.0 46568 [027] 79357.842179: damon:damon_aggregated: target_id=0 nr_regions=11 122509119488-135708762112: 0 864
     [...]
-- 
2.39.2

[PATCH 5/9] Docs/admin-guide/mm/damon/usage: document 'DEPRECATED' file of DAMON debugfs interface

[SeongJae Park]

Document the newly added DAMON debugfs interface deprecation notice file
on the usage document.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/usage.rst | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index f2feabb4bd35..5d3df18dfb9f 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -628,9 +628,16 @@ debugfs Interface (DEPRECATED!)
   move, please report your usecase to damon@lists.linux.dev and
   linux-mm@kvack.org.
 
-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/``.
+DAMON exports nine files, ``DEPRECATED``, ``attrs``, ``target_ids``,
+``init_regions``, ``schemes``, ``monitor_on``, ``kdamond_pid``, ``mk_contexts``
+and ``rm_contexts`` under its debugfs directory, ``<debugfs>/damon/``.
+
+
+``DEPRECATED`` is a read-only file for the DAMON debugfs interface deprecation
+notice.  Reading it returns the deprecation notice, as below::
+
+    # cat DEPRECATED
+    DAMON debugfs interface is deprecated, so users should move to DAMON_SYSFS. If you cannot, please report your usecase to damon@lists.linux.dev and linux-mm@kvack.org.
 
 
 Attributes
-- 
2.39.2

[PATCH 8/9] Docs/admin-guide/mm/damon/usage: update for monitor_on renaming

[SeongJae Park]

Update DAMON debugfs interface sections on the usage document to reflect
the fact that 'monitor_on' file has renamed to 'monitor_on_DEPRECATED'.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/usage.rst | 29 ++++++++++----------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index 5d3df18dfb9f..58c34e66b31b 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -629,8 +629,9 @@ debugfs Interface (DEPRECATED!)
   linux-mm@kvack.org.
 
 DAMON exports nine files, ``DEPRECATED``, ``attrs``, ``target_ids``,
-``init_regions``, ``schemes``, ``monitor_on``, ``kdamond_pid``, ``mk_contexts``
-and ``rm_contexts`` under its debugfs directory, ``<debugfs>/damon/``.
+``init_regions``, ``schemes``, ``monitor_on_DEPRECATED``, ``kdamond_pid``,
+``mk_contexts`` and ``rm_contexts`` under its debugfs directory,
+``<debugfs>/damon/``.
 
 
 ``DEPRECATED`` is a read-only file for the DAMON debugfs interface deprecation
@@ -855,16 +856,16 @@ Turning On/Off
 
 Setting the files as described above doesn't incur effect unless you explicitly
 start the monitoring.  You can start, stop, and check the current status of the
-monitoring by writing to and reading from the ``monitor_on`` file.  Writing
-``on`` to the file starts the monitoring of the targets with the attributes.
-Writing ``off`` to the file stops those.  DAMON also stops if every target
-process is terminated.  Below example commands turn on, off, and check the
-status of DAMON::
+monitoring by writing to and reading from the ``monitor_on_DEPRECATED`` file.
+Writing ``on`` to the file starts the monitoring of the targets with the
+attributes.  Writing ``off`` to the file stops those.  DAMON also stops if
+every target process is terminated.  Below example commands turn on, off, and
+check the status of DAMON::
 
     # cd <debugfs>/damon
-    # echo on > monitor_on
-    # echo off > monitor_on
-    # cat monitor_on
+    # echo on > monitor_on_DEPRECATED
+    # echo off > monitor_on_DEPRECATED
+    # cat monitor_on_DEPRECATED
     off
 
 Please note that you cannot write to the above-mentioned debugfs files while
@@ -880,11 +881,11 @@ 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
+    # cat monitor_on_DEPRECATED
     off
     # cat kdamond_pid
     none
-    # echo on > monitor_on
+    # echo on > monitor_on_DEPRECATED
     # cat kdamond_pid
     18594
 
@@ -914,5 +915,5 @@ directory by putting the name of the context to the ``rm_contexts`` file. ::
     # 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.
+Note that ``mk_contexts``, ``rm_contexts``, and ``monitor_on_DEPRECATED`` files
+are in the root directory only.
-- 
2.39.2

[PATCH 9/9] Docs/translations/damon/usage: update for monitor_on renaming

[SeongJae Park]

Update DAMON debugfs interface sections on the translated usage
documents to reflect the fact that 'monitor_on' file has renamed to
'monitor_on_DEPRECATED'.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 .../zh_CN/admin-guide/mm/damon/usage.rst      | 20 +++++++++----------
 .../zh_TW/admin-guide/mm/damon/usage.rst      | 20 +++++++++----------
 2 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/Documentation/translations/zh_CN/admin-guide/mm/damon/usage.rst b/Documentation/translations/zh_CN/admin-guide/mm/damon/usage.rst
index 17b9949d9b43..da2745464ece 100644
--- a/Documentation/translations/zh_CN/admin-guide/mm/damon/usage.rst
+++ b/Documentation/translations/zh_CN/admin-guide/mm/damon/usage.rst
@@ -344,7 +344,7 @@ debugfs接口
   :ref:`sysfs接口<sysfs_interface>`。
 
 DAMON导出了八个文件, ``attrs``, ``target_ids``, ``init_regions``,
-``schemes``, ``monitor_on``, ``kdamond_pid``, ``mk_contexts`` 和
+``schemes``, ``monitor_on_DEPRECATED``, ``kdamond_pid``, ``mk_contexts`` 和
 ``rm_contexts`` under its debugfs directory, ``<debugfs>/damon/``.
 
 
@@ -521,15 +521,15 @@ DAMON导出了八个文件, ``attrs``, ``target_ids``, ``init_regions``,
 开关
 ----
 
-除非你明确地启动监测，否则如上所述的文件设置不会产生效果。你可以通过写入和读取 ``monitor_on``
+除非你明确地启动监测，否则如上所述的文件设置不会产生效果。你可以通过写入和读取 ``monitor_on_DEPRECATED``
 文件来启动、停止和检查监测的当前状态。写入 ``on`` 该文件可以启动对有属性的目标的监测。写入
 ``off`` 该文件则停止这些目标。如果每个目标进程被终止，DAMON也会停止。下面的示例命令开启、关
 闭和检查DAMON的状态::
 
     # cd <debugfs>/damon
-    # echo on > monitor_on
-    # echo off > monitor_on
-    # cat monitor_on
+    # echo on > monitor_on_DEPRECATED
+    # echo off > monitor_on_DEPRECATED
+    # cat monitor_on_DEPRECATED
     off
 
 请注意，当监测开启时，你不能写到上述的debugfs文件。如果你在DAMON运行时写到这些文件，将会返
@@ -543,11 +543,11 @@ DAMON通过一个叫做kdamond的内核线程来进行请求监测。你可以
 得该线程的 ``pid`` 。当监测被 ``关闭`` 时，读取该文件不会返回任何信息::
 
     # cd <debugfs>/damon
-    # cat monitor_on
+    # cat monitor_on_DEPRECATED
     off
     # cat kdamond_pid
     none
-    # echo on > monitor_on
+    # echo on > monitor_on_DEPRECATED
     # cat kdamond_pid
     18594
 
@@ -574,7 +574,7 @@ DAMON通过一个叫做kdamond的内核线程来进行请求监测。你可以
     # ls foo
     # ls: cannot access 'foo': No such file or directory
 
-注意， ``mk_contexts`` 、 ``rm_contexts`` 和 ``monitor_on`` 文件只在根目录下。
+注意， ``mk_contexts`` 、 ``rm_contexts`` 和 ``monitor_on_DEPRECATED`` 文件只在根目录下。
 
 
 监测结果的监测点
@@ -583,9 +583,9 @@ DAMON通过一个叫做kdamond的内核线程来进行请求监测。你可以
 DAMON通过一个tracepoint ``damon:damon_aggregated`` 提供监测结果.  当监测开启时，你可
 以记录追踪点事件，并使用追踪点支持工具如perf显示结果。比如说::
 
-    # echo on > monitor_on
+    # echo on > monitor_on_DEPRECATED
     # perf record -e damon:damon_aggregated &
     # sleep 5
     # kill 9 $(pidof perf)
-    # echo off > monitor_on
+    # echo off > monitor_on_DEPRECATED
     # perf script
diff --git a/Documentation/translations/zh_TW/admin-guide/mm/damon/usage.rst b/Documentation/translations/zh_TW/admin-guide/mm/damon/usage.rst
index 6dee719a32ea..7464279f9b7d 100644
--- a/Documentation/translations/zh_TW/admin-guide/mm/damon/usage.rst
+++ b/Documentation/translations/zh_TW/admin-guide/mm/damon/usage.rst
@@ -344,7 +344,7 @@ debugfs接口
   :ref:`sysfs接口<sysfs_interface>`。
 
 DAMON導出了八個文件, ``attrs``, ``target_ids``, ``init_regions``,
-``schemes``, ``monitor_on``, ``kdamond_pid``, ``mk_contexts`` 和
+``schemes``, ``monitor_on_DEPRECATED``, ``kdamond_pid``, ``mk_contexts`` 和
 ``rm_contexts`` under its debugfs directory, ``<debugfs>/damon/``.
 
 
@@ -521,15 +521,15 @@ DAMON導出了八個文件, ``attrs``, ``target_ids``, ``init_regions``,
 開關
 ----
 
-除非你明確地啓動監測，否則如上所述的文件設置不會產生效果。你可以通過寫入和讀取 ``monitor_on``
+除非你明確地啓動監測，否則如上所述的文件設置不會產生效果。你可以通過寫入和讀取 ``monitor_on_DEPRECATED``
 文件來啓動、停止和檢查監測的當前狀態。寫入 ``on`` 該文件可以啓動對有屬性的目標的監測。寫入
 ``off`` 該文件則停止這些目標。如果每個目標進程被終止，DAMON也會停止。下面的示例命令開啓、關
 閉和檢查DAMON的狀態::
 
     # cd <debugfs>/damon
-    # echo on > monitor_on
-    # echo off > monitor_on
-    # cat monitor_on
+    # echo on > monitor_on_DEPRECATED
+    # echo off > monitor_on_DEPRECATED
+    # cat monitor_on_DEPRECATED
     off
 
 請注意，當監測開啓時，你不能寫到上述的debugfs文件。如果你在DAMON運行時寫到這些文件，將會返
@@ -543,11 +543,11 @@ DAMON通過一個叫做kdamond的內核線程來進行請求監測。你可以
 得該線程的 ``pid`` 。當監測被 ``關閉`` 時，讀取該文件不會返回任何信息::
 
     # cd <debugfs>/damon
-    # cat monitor_on
+    # cat monitor_on_DEPRECATED
     off
     # cat kdamond_pid
     none
-    # echo on > monitor_on
+    # echo on > monitor_on_DEPRECATED
     # cat kdamond_pid
     18594
 
@@ -574,7 +574,7 @@ DAMON通過一個叫做kdamond的內核線程來進行請求監測。你可以
     # ls foo
     # ls: cannot access 'foo': No such file or directory
 
-注意， ``mk_contexts`` 、 ``rm_contexts`` 和 ``monitor_on`` 文件只在根目錄下。
+注意， ``mk_contexts`` 、 ``rm_contexts`` 和 ``monitor_on_DEPRECATED`` 文件只在根目錄下。
 
 
 監測結果的監測點
@@ -583,10 +583,10 @@ DAMON通過一個叫做kdamond的內核線程來進行請求監測。你可以
 DAMON通過一個tracepoint ``damon:damon_aggregated`` 提供監測結果.  當監測開啓時，你可
 以記錄追蹤點事件，並使用追蹤點支持工具如perf顯示結果。比如說::
 
-    # echo on > monitor_on
+    # echo on > monitor_on_DEPRECATED
     # perf record -e damon:damon_aggregated &
     # sleep 5
     # kill 9 $(pidof perf)
-    # echo off > monitor_on
+    # echo off > monitor_on_DEPRECATED
     # perf script
 
-- 
2.39.2

Re: [PATCH 9/9] Docs/translations/damon/usage: update for monitor_on renaming

[kuiliang Shi]

LGTM

Reviewed-by: Alex Shi <alexs@kernel.org>

On 1/30/24 9:35 AM, SeongJae Park wrote:
> Update DAMON debugfs interface sections on the translated usage
> documents to reflect the fact that 'monitor_on' file has renamed to
> 'monitor_on_DEPRECATED'.
> 
> Signed-off-by: SeongJae Park <sj@kernel.org>
> ---
>  .../zh_CN/admin-guide/mm/damon/usage.rst      | 20 +++++++++----------
>  .../zh_TW/admin-guide/mm/damon/usage.rst      | 20 +++++++++----------
>  2 files changed, 20 insertions(+), 20 deletions(-)
> 
> diff --git a/Documentation/translations/zh_CN/admin-guide/mm/damon/usage.rst b/Documentation/translations/zh_CN/admin-guide/mm/damon/usage.rst
> index 17b9949d9b43..da2745464ece 100644
> --- a/Documentation/translations/zh_CN/admin-guide/mm/damon/usage.rst
> +++ b/Documentation/translations/zh_CN/admin-guide/mm/damon/usage.rst
> @@ -344,7 +344,7 @@ debugfs接口
>    :ref:`sysfs接口<sysfs_interface>`。
>  
>  DAMON导出了八个文件, ``attrs``, ``target_ids``, ``init_regions``,
> -``schemes``, ``monitor_on``, ``kdamond_pid``, ``mk_contexts`` 和
> +``schemes``, ``monitor_on_DEPRECATED``, ``kdamond_pid``, ``mk_contexts`` 和
>  ``rm_contexts`` under its debugfs directory, ``<debugfs>/damon/``.
>  
>  
> @@ -521,15 +521,15 @@ DAMON导出了八个文件, ``attrs``, ``target_ids``, ``init_regions``,
>  开关
>  ----
>  
> -除非你明确地启动监测，否则如上所述的文件设置不会产生效果。你可以通过写入和读取 ``monitor_on``
> +除非你明确地启动监测，否则如上所述的文件设置不会产生效果。你可以通过写入和读取 ``monitor_on_DEPRECATED``
>  文件来启动、停止和检查监测的当前状态。写入 ``on`` 该文件可以启动对有属性的目标的监测。写入
>  ``off`` 该文件则停止这些目标。如果每个目标进程被终止，DAMON也会停止。下面的示例命令开启、关
>  闭和检查DAMON的状态::
>  
>      # cd <debugfs>/damon
> -    # echo on > monitor_on
> -    # echo off > monitor_on
> -    # cat monitor_on
> +    # echo on > monitor_on_DEPRECATED
> +    # echo off > monitor_on_DEPRECATED
> +    # cat monitor_on_DEPRECATED
>      off
>  
>  请注意，当监测开启时，你不能写到上述的debugfs文件。如果你在DAMON运行时写到这些文件，将会返
> @@ -543,11 +543,11 @@ DAMON通过一个叫做kdamond的内核线程来进行请求监测。你可以
>  得该线程的 ``pid`` 。当监测被 ``关闭`` 时，读取该文件不会返回任何信息::
>  
>      # cd <debugfs>/damon
> -    # cat monitor_on
> +    # cat monitor_on_DEPRECATED
>      off
>      # cat kdamond_pid
>      none
> -    # echo on > monitor_on
> +    # echo on > monitor_on_DEPRECATED
>      # cat kdamond_pid
>      18594
>  
> @@ -574,7 +574,7 @@ DAMON通过一个叫做kdamond的内核线程来进行请求监测。你可以
>      # ls foo
>      # ls: cannot access 'foo': No such file or directory
>  
> -注意， ``mk_contexts`` 、 ``rm_contexts`` 和 ``monitor_on`` 文件只在根目录下。
> +注意， ``mk_contexts`` 、 ``rm_contexts`` 和 ``monitor_on_DEPRECATED`` 文件只在根目录下。
>  
>  
>  监测结果的监测点
> @@ -583,9 +583,9 @@ DAMON通过一个叫做kdamond的内核线程来进行请求监测。你可以
>  DAMON通过一个tracepoint ``damon:damon_aggregated`` 提供监测结果.  当监测开启时，你可
>  以记录追踪点事件，并使用追踪点支持工具如perf显示结果。比如说::
>  
> -    # echo on > monitor_on
> +    # echo on > monitor_on_DEPRECATED
>      # perf record -e damon:damon_aggregated &
>      # sleep 5
>      # kill 9 $(pidof perf)
> -    # echo off > monitor_on
> +    # echo off > monitor_on_DEPRECATED
>      # perf script
> diff --git a/Documentation/translations/zh_TW/admin-guide/mm/damon/usage.rst b/Documentation/translations/zh_TW/admin-guide/mm/damon/usage.rst
> index 6dee719a32ea..7464279f9b7d 100644
> --- a/Documentation/translations/zh_TW/admin-guide/mm/damon/usage.rst
> +++ b/Documentation/translations/zh_TW/admin-guide/mm/damon/usage.rst
> @@ -344,7 +344,7 @@ debugfs接口
>    :ref:`sysfs接口<sysfs_interface>`。
>  
>  DAMON導出了八個文件, ``attrs``, ``target_ids``, ``init_regions``,
> -``schemes``, ``monitor_on``, ``kdamond_pid``, ``mk_contexts`` 和
> +``schemes``, ``monitor_on_DEPRECATED``, ``kdamond_pid``, ``mk_contexts`` 和
>  ``rm_contexts`` under its debugfs directory, ``<debugfs>/damon/``.
>  
>  
> @@ -521,15 +521,15 @@ DAMON導出了八個文件, ``attrs``, ``target_ids``, ``init_regions``,
>  開關
>  ----
>  
> -除非你明確地啓動監測，否則如上所述的文件設置不會產生效果。你可以通過寫入和讀取 ``monitor_on``
> +除非你明確地啓動監測，否則如上所述的文件設置不會產生效果。你可以通過寫入和讀取 ``monitor_on_DEPRECATED``
>  文件來啓動、停止和檢查監測的當前狀態。寫入 ``on`` 該文件可以啓動對有屬性的目標的監測。寫入
>  ``off`` 該文件則停止這些目標。如果每個目標進程被終止，DAMON也會停止。下面的示例命令開啓、關
>  閉和檢查DAMON的狀態::
>  
>      # cd <debugfs>/damon
> -    # echo on > monitor_on
> -    # echo off > monitor_on
> -    # cat monitor_on
> +    # echo on > monitor_on_DEPRECATED
> +    # echo off > monitor_on_DEPRECATED
> +    # cat monitor_on_DEPRECATED
>      off
>  
>  請注意，當監測開啓時，你不能寫到上述的debugfs文件。如果你在DAMON運行時寫到這些文件，將會返
> @@ -543,11 +543,11 @@ DAMON通過一個叫做kdamond的內核線程來進行請求監測。你可以
>  得該線程的 ``pid`` 。當監測被 ``關閉`` 時，讀取該文件不會返回任何信息::
>  
>      # cd <debugfs>/damon
> -    # cat monitor_on
> +    # cat monitor_on_DEPRECATED
>      off
>      # cat kdamond_pid
>      none
> -    # echo on > monitor_on
> +    # echo on > monitor_on_DEPRECATED
>      # cat kdamond_pid
>      18594
>  
> @@ -574,7 +574,7 @@ DAMON通過一個叫做kdamond的內核線程來進行請求監測。你可以
>      # ls foo
>      # ls: cannot access 'foo': No such file or directory
>  
> -注意， ``mk_contexts`` 、 ``rm_contexts`` 和 ``monitor_on`` 文件只在根目錄下。
> +注意， ``mk_contexts`` 、 ``rm_contexts`` 和 ``monitor_on_DEPRECATED`` 文件只在根目錄下。
>  
>  
>  監測結果的監測點
> @@ -583,10 +583,10 @@ DAMON通過一個叫做kdamond的內核線程來進行請求監測。你可以
>  DAMON通過一個tracepoint ``damon:damon_aggregated`` 提供監測結果.  當監測開啓時，你可
>  以記錄追蹤點事件，並使用追蹤點支持工具如perf顯示結果。比如說::
>  
> -    # echo on > monitor_on
> +    # echo on > monitor_on_DEPRECATED
>      # perf record -e damon:damon_aggregated &
>      # sleep 5
>      # kill 9 $(pidof perf)
> -    # echo off > monitor_on
> +    # echo off > monitor_on_DEPRECATED
>      # perf script
>