selftests/damon/_damon_sysfs: support DAMOS apply interval

Update the test-purpose DAMON sysfs control Python module to support DAMOS
apply interval.

Link: https://lkml.kernel.org/r/20240207203134.69976-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/damon/_damon_sysfs: support DAMOS stats

Update the test-purpose DAMON sysfs control Python module to support DAMOS
stats.

Link: https://lkml.kernel.org/r/20240207203134.69976-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/damon/_damon_sysfs: support DAMOS quota

Patch series "selftests/damon: add more tests for core functionalities and
corner cases".

Continue DAMON selftests' test coverage improvement works with a trivial
improvement of the test code itself. The sequence of the patches in
patchset is as follows.

The first five patches add two DAMON core functionalities tests. Those
begins with three patches (patches 1-3) that update the test-purpose DAMON
sysfs interface wrapper to support DAMOS quota, stats, and apply interval
features, respectively. The fourth patch implements and adds a selftest
for DAMOS quota feature, using the DAMON sysfs interface wrapper's newly
added support of the quota and the stats feature. The fifth patch further
implements and adds a selftest for DAMOS apply interval using the DAMON
sysfs interface wrapper's newly added support of the apply interval and
the stats feature.

Two patches (patches 6 and 7) for implementing and adding two corner cases
handling selftests follow. Those try to avoid two previously fixed bugs
from recurring.

Finally, a patch for making DAMON debugfs selftests dependency checker to
use /proc/mounts instead of the hard-coded mount point assumption follows.


This patch (of 8):

Update the test-purpose DAMON sysfs control Python module to support DAMOS
quota.

Link: https://lkml.kernel.org/r/20240207203134.69976-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240207203134.69976-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/damon/_damon_sysfs: implement updat_schemes_tried_bytes command

Implement update_schemes_tried_bytes command of DAMON sysfs interface in
_damon_sysfs.py. It is not only making the update, but also read the
updated value from the sysfs interface and store it in the Kdamond python
objects so that the user of the module can easily get the value.

Link: https://lkml.kernel.org/r/20231212194810.54457-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/damon/_damon_sysfs: implement kdamonds start function

Extend the tests-writing-purpose DAMON sysfs control module to support the
kdamonds start functionality.

Link: https://lkml.kernel.org/r/20231212194810.54457-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/damon: implement a python module for test-purpose DAMON sysfs controls

Patch series "selftests/damon: add Python-written DAMON functionality
tests", v2.

DAMON exports most of its functionality via its sysfs interface. Hence
most DAMON functionality tests could be implemented using the interface.
However, because the interfaces require simple but multiple operations for
many controls, writing all such tests from the scratch could be repetitive
and time consuming.

Implement a minimum DAMON sysfs control module, and a couple of DAMON
functionality tests using the control module. The first test is for
ensuring minimum accuracy of data access monitoring, and the second test
is for finding if a previously found and fixed bug is introduced again.

Note that the DAMON sysfs control module is only for avoiding duplicating
code in tests. For convenient and general control of DAMON, users should
use DAMON user-space tools that developed for the purpose, such as
damo[1].

[1] https://github.com/damonitor/damo

Patches Sequence
----------------

This patchset is constructed with five patches. The first three patches
implement a Python-written test implementation-purpose DAMON sysfs control
module. The implementation is incrementally done in the sequence of the
basic data structure (first patch) first, kdamonds start command (second
patch) next, and finally DAMOS tried bytes update command (third patch).

Then two patches for implementing selftests using the module follows. The
fourth patch implements a basic functionality test of DAMON for working
set estimation accuracy. Finally, the fifth patch implements a corner
case test for a previously found bug.


This patch (of 5):

Implement a python module for DAMON sysfs controls. The module is aimed
to be useful for writing DAMON functionality tests in future.
Nonetheless, this module is only representing a subset of DAMON sysfs
files. Following commits will implement more DAMON sysfs controls.

Link: https://lkml.kernel.org/r/20231212194810.54457-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231212194810.54457-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>