[RFC PATCH 0/8] DAMOS: Introduce Aim-oriented Feedback-driven Aggressiveness Auto Tuning

[RFC PATCH 0/8] DAMOS: Introduce Aim-oriented Feedback-driven Aggressiveness Auto Tuning

[SeongJae Park]

Another candidate of the subject was "Let users feed and tame DAMOS".

DAMOS Control Difficulty
========================

DAMOS helps users easily implementing effective access pattern aware
system operations.  However, controlling DAMOS in wild is not that easy.
The basic way to control DAMON is specifying the target access pattern.
Hence, the user is assumed to know the access pattern of the system and
the workloads well.  Though some good tools including DAMON can help
that, it requires time and resource, and the cost depends on the
complexity and the dynamicity of the system and workloads.  After all,
the access pattern consist of three ranges, namely ranges of access
rate, age, and size of the regions.  Tuning six parameters is already
complex.  It is not doable for everyone.

To ease the control, DAMOS allows users to set the upper-limit of the
schemes's aggressiveness, namely DAMOS quota.  Then DAMOS prioritizes
regions to apply the action under the limit based on the action and the
access pattern of the regions.  For example, use can ask DAMOS to page
out up to 100 MiB of memory regions per second.  Then DAMOS pages out
regions that not accessed for longer time first under the limit.  This
allows users to set access pattern bit more naively, and focus on only
the one parameter, the quota.  That is, the number of parameters to tune
with special care can be reduced from six to one.

Still, however, the optimal value for the quota depends on the system
and the workloads' characteristics, so not that simple.  The number of
parameters to tune can also increase again if the user needs to run
multiple schemes, e.g., collapsing hot pages into THP while splitting
cold pages into regular pages.

In short, the existing approach asks users to find the perfect or
adapted tuning and instruct DAMOS how to work.  It requires users to be
deligent.  That's not a virtue of human, but the machine.

Aim-oriented Feedback-driven DAMOS Quota Auto Tuning
====================================================

Most users would start using DAMOS since there is something they want to
achieve with DAMOS.  Having such goal metrics like SLO is common.
Hence, a better approach would be letting users inform DAMOS what they
aim to achieve, and how well DAMOS is doing that.  Then DAMOS can
somehow make it.  In detail, users provide feedback for each DAMOS
scheme.  DAMOS then tune the quota of each scheme based on the users'
feedback and the current quota values.

This patchset implements the idea.

Implementation
--------------

The core logic implementation is in the first patch.  In short, it uses
below simple feedback loop algorithm to get next aggressiveness from the
current aggressiveness and the feedback (target_core and current_score)
for the current aggressiveness.

    f(n, target_score, current_score) =
        max(f(n - 1) * ((target_score - current_score) / target_score + 1), 1)

Note that this algorithm assumes the aggressiveness and the score are
positively proportional.  Making it true is the feedback provider's
responsibility.

Test Results
------------

To show if this provides the expected benefit, we extend the performance
tests of damon-tests suite to support virtual address space-based
proactive reclamation scheme that aims 0.5% last 10 seconds some memory
PSI.  The test suite runs PARSEC3 and SPLASH-2X workloads with the
scheme and measure the runtime, the RSS, and the PSI for memory (some).
We do same with the same scheme but not having the goal, and yet another
variant of it that the target access patterns of the scheme is tuned for
each workload, in a offline-tuning approach named DAMOOS[1].

The results that normalized to the output that made without any scheme
are as below.  The PSI for original run (without any scheme) was zero.
To avoid divide-by-zero, we normalize the value to that of Not-tuned
scheme's result.

    xx      Not-tuned         Offline-tuned     Online-tuned
    RSS     0.622688178226118 0.787950678944904 0.740093483278979
    runtime 1.11767826657912  1.0564674983585   1.0910833880499
    PSI     1                 0.727521443794069 0.308498846350299

The not-tuned scheme acheives about 38.7% memory saving but incur about
11.7% runtime slowdown.  The offline-tuned scheme achieves about 22.2%
memory saving with about 5.5% runtiem slowdown.  It also achieves about
28.2% PSI saving.  The online-tuned scheme achieves about 26% memory
saving with about 9.1% runtime slowdown.  It also achieves about 69.1%
PSI saving.  Given the online-tuned version is using this RFC level
implementation and the goal (0.5% last-10 secs memory PSI) was made
after only a few experiments within a day, I think this results show
some potential of this feedback-driven auto tuning approach.

The test code is available[2], so you can reproduce on your system.


[1] https://www.amazon.science/publications/daos-data-access-aware-operating-system
[2] https://github.com/damonitor/damon-tests/commit/3f884e61193f0166b8724554b6d06b0c449a712d


Patches Sequence
================

The first four patches implement the core logic and user interfaces for
the auto tuning.  The first patch implements the core logic for the auto
tuning, and the API for DAMOS users in the kernel space.  The second
patch implements basic file operations of DAMON sysfs directories and
files that will be used for setting the goals and providing the
feedback.  The third patch connects the quota goals files inputs to the
DAMOS core logic.  Finally the fourth patch implements a dedicated DAMOS
sysfs command for efficiently committing the quota goals feedback.

Two patches for simple test of the logic and interfaces follow.  The
fifth patch implements the core logic unit test.  The sixth patch
implements a selftest for the DAMON Sysfs interface for the goals.

Finally, two patches for documentation follows.  The seventh patch
documents the design of the feature.  The final eighth patch updates the
usage document for the features.

SeongJae Park (8):
  mm/damon/core: implement goal-oriented feedback-driven quota
    auto-tuning
  mm/damon/sysfs-schemes: implement scheme quota goals directory
  mm/damon/sysfs-schemes: commit damos quota goals user input to DAMOS
    quota auto-tuning
  mm/damon/sysfs-schemes: implement a command for scheme quota goals
    only commit
  mm/damon/core-test: add a unit test for the feedback loop algorithm
  selftests/damon: test quota goals directory
  Docs/mm/damon/design: Document DAMOS quota auto tuning
  Docs/admin-guide/mm/damon/usage: update for quota goals

 Documentation/admin-guide/mm/damon/usage.rst |  25 +-
 Documentation/mm/damon/design.rst            |  11 +
 include/linux/damon.h                        |  19 ++
 mm/damon/core-test.h                         |  32 +++
 mm/damon/core.c                              |  65 ++++-
 mm/damon/sysfs-common.h                      |   3 +
 mm/damon/sysfs-schemes.c                     | 272 ++++++++++++++++++-
 mm/damon/sysfs.c                             |  27 ++
 tools/testing/selftests/damon/sysfs.sh       |  27 ++
 9 files changed, 463 insertions(+), 18 deletions(-)


base-commit: 4f26b84c39fbc6b03208674681bfde06e0bce25a
-- 
2.34.1

[RFC PATCH 0/8] DAMOS: Introduce Aim-oriented Feedback-driven Aggressiveness Auto Tuning

[SeongJae Park]

Another candidate of the subject was "Let users feed and tame DAMOS".

DAMOS Control Difficulty
========================

DAMOS helps users easily implementing effective access pattern aware
system operations.  However, controlling DAMOS in wild is not that easy.
The basic way to control DAMON is specifying the target access pattern.
Hence, the user is assumed to know the access pattern of the system and
the workloads well.  Though some good tools including DAMON can help
that, it requires time and resource, and the cost depends on the
complexity and the dynamicity of the system and workloads.  After all,
the access pattern consist of three ranges, namely ranges of access
rate, age, and size of the regions.  Tuning six parameters is already
complex.  It is not doable for everyone.

To ease the control, DAMOS allows users to set the upper-limit of the
schemes's aggressiveness, namely DAMOS quota.  Then DAMOS prioritizes
regions to apply the action under the limit based on the action and the
access pattern of the regions.  For example, use can ask DAMOS to page
out up to 100 MiB of memory regions per second.  Then DAMOS pages out
regions that not accessed for longer time first under the limit.  This
allows users to set access pattern bit more naively, and focus on only
the one parameter, the quota.  That is, the number of parameters to tune
with special care can be reduced from six to one.

Still, however, the optimal value for the quota depends on the system
and the workloads' characteristics, so not that simple.  The number of
parameters to tune can also increase again if the user needs to run
multiple schemes, e.g., collapsing hot pages into THP while splitting
cold pages into regular pages.

In short, the existing approach asks users to find the perfect or
adapted tuning and instruct DAMOS how to work.  It requires users to be
deligent.  That's not a virtue of human, but the machine.

Aim-oriented Feedback-driven DAMOS Quota Auto Tuning
====================================================

Most users would start using DAMOS since there is something they want to
achieve with DAMOS.  Having such goal metrics like SLO is common.
Hence, a better approach would be letting users inform DAMOS what they
aim to achieve, and how well DAMOS is doing that.  Then DAMOS can
somehow make it.  In detail, users provide feedback for each DAMOS
scheme.  DAMOS then tune the quota of each scheme based on the users'
feedback and the current quota values.

This patchset implements the idea.

Implementation
--------------

The core logic implementation is in the first patch.  In short, it uses
below simple feedback loop algorithm to get next aggressiveness from the
current aggressiveness and the feedback (target_core and current_score)
for the current aggressiveness.

    f(n, target_score, current_score) =
        max(f(n - 1) * ((target_score - current_score) / target_score + 1), 1)

Note that this algorithm assumes the aggressiveness and the score are
positively proportional.  Making it true is the feedback provider's
responsibility.

Test Results
------------

To show if this provides the expected benefit, we extend the performance
tests of damon-tests suite to support virtual address space-based
proactive reclamation scheme that aims 0.5% last 10 seconds some memory
PSI.  The test suite runs PARSEC3 and SPLASH-2X workloads with the
scheme and measure the runtime, the RSS, and the PSI for memory (some).
We do same with the same scheme but not having the goal, and yet another
variant of it that the target access patterns of the scheme is tuned for
each workload, in a offline-tuning approach named DAMOOS[1].

The results that normalized to the output that made without any scheme
are as below.  The PSI for original run (without any scheme) was zero.
To avoid divide-by-zero, we normalize the value to that of Not-tuned
scheme's result.

    xx      Not-tuned         Offline-tuned     Online-tuned
    RSS     0.622688178226118 0.787950678944904 0.740093483278979
    runtime 1.11767826657912  1.0564674983585   1.0910833880499
    PSI     1                 0.727521443794069 0.308498846350299

The not-tuned scheme acheives about 38.7% memory saving but incur about
11.7% runtime slowdown.  The offline-tuned scheme achieves about 22.2%
memory saving with about 5.5% runtiem slowdown.  It also achieves about
28.2% PSI saving.  The online-tuned scheme achieves about 26% memory
saving with about 9.1% runtime slowdown.  It also achieves about 69.1%
PSI saving.  Given the online-tuned version is using this RFC level
implementation and the goal (0.5% last-10 secs memory PSI) was made
after only a few experiments within a day, I think this results show
some potential of this feedback-driven auto tuning approach.

The test code is available[2], so you can reproduce on your system.


[1] https://www.amazon.science/publications/daos-data-access-aware-operating-system
[2] https://github.com/damonitor/damon-tests/commit/3f884e61193f0166b8724554b6d06b0c449a712d


Patches Sequence
================

The first four patches implement the core logic and user interfaces for
the auto tuning.  The first patch implements the core logic for the auto
tuning, and the API for DAMOS users in the kernel space.  The second
patch implements basic file operations of DAMON sysfs directories and
files that will be used for setting the goals and providing the
feedback.  The third patch connects the quota goals files inputs to the
DAMOS core logic.  Finally the fourth patch implements a dedicated DAMOS
sysfs command for efficiently committing the quota goals feedback.

Two patches for simple test of the logic and interfaces follow.  The
fifth patch implements the core logic unit test.  The sixth patch
implements a selftest for the DAMON Sysfs interface for the goals.

Finally, two patches for documentation follows.  The seventh patch
documents the design of the feature.  The final eighth patch updates the
usage document for the features.

SeongJae Park (8):
  mm/damon/core: implement goal-oriented feedback-driven quota
    auto-tuning
  mm/damon/sysfs-schemes: implement scheme quota goals directory
  mm/damon/sysfs-schemes: commit damos quota goals user input to DAMOS
    quota auto-tuning
  mm/damon/sysfs-schemes: implement a command for scheme quota goals
    only commit
  mm/damon/core-test: add a unit test for the feedback loop algorithm
  selftests/damon: test quota goals directory
  Docs/mm/damon/design: Document DAMOS quota auto tuning
  Docs/admin-guide/mm/damon/usage: update for quota goals

 Documentation/admin-guide/mm/damon/usage.rst |  25 +-
 Documentation/mm/damon/design.rst            |  11 +
 include/linux/damon.h                        |  19 ++
 mm/damon/core-test.h                         |  32 +++
 mm/damon/core.c                              |  65 ++++-
 mm/damon/sysfs-common.h                      |   3 +
 mm/damon/sysfs-schemes.c                     | 272 ++++++++++++++++++-
 mm/damon/sysfs.c                             |  27 ++
 tools/testing/selftests/damon/sysfs.sh       |  27 ++
 9 files changed, 463 insertions(+), 18 deletions(-)


base-commit: 4f26b84c39fbc6b03208674681bfde06e0bce25a
-- 
2.34.1

[RFC PATCH 1/8] mm/damon/core: implement goal-oriented feedback-driven quota auto-tuning

[SeongJae Park]

Users can effectively control the upper-most aggressiveness of DAMOS
schemes using the quota feature.  The quota provides best result under
the aggressiveness limit since it prioritizes regions based on the
access pattern.  Finding the best value, which could depend on dynamic
characteristics of the system and the workloads, is still challenging,
though.

Implement a simple feedback-driven tuning mechanism and use it for
automatic tuning of DAMOS quota.  The implementation allows users to
provide the feedback by setting a feedback score returning callback
function.  Then DAMOS periodically adjusts the quota based on the return
value of the function calls.

Note that the absolute-value based time/size quotas still work as the
maximum hard limit of the scheme's aggressiveness.  The feedback-driven
auto-tuned quota is applied only if it is not exceeding the manually set
maximum limit.  Same for the scheme-target access pattern and filters
like other features.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/damon.h | 19 +++++++++++++
 mm/damon/core.c       | 65 +++++++++++++++++++++++++++++++++++++------
 2 files changed, 75 insertions(+), 9 deletions(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 89f5ca041848..9d46e0b39456 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -136,6 +136,8 @@ enum damos_action {
  * @weight_nr_accesses:	Weight of the region's nr_accesses for prioritization.
  * @weight_age:		Weight of the region's age for prioritization.
  *
+ * @get_score:		Feedback function for self-tuning quota.
+ *
  * To avoid consuming too much CPU time or IO resources for applying the
  * &struct damos->action to large memory, DAMON allows users to set time and/or
  * size quotas.  The quotas can be set by writing non-zero values to &ms and
@@ -153,6 +155,17 @@ enum damos_action {
  * You could customize the prioritization logic by setting &weight_sz,
  * &weight_nr_accesses, and &weight_age, because monitoring operations are
  * encouraged to respect those.
+ *
+ * If @get_score function pointer is set, DAMON calls it back and get the
+ * return value of it for every @reset_interval.  Then, DAMON adjusts the
+ * effective quota using the return value as a feedback score to the current
+ * quota, using its internal feedback loop algorithm.
+ *
+ * The feedback loop algorithem assumes the quota input and the feedback score
+ * output are in a positive proportional relationship, and the goal of the
+ * tuning is getting the feedback screo value of 10,000.  If @ms and/or @sz are
+ * set together, those work as a hard limit quota.  If neither @ms nor @sz are
+ * set, the mechanism starts from the quota of one byte.
  */
 struct damos_quota {
 	unsigned long ms;
@@ -163,6 +176,9 @@ struct damos_quota {
 	unsigned int weight_nr_accesses;
 	unsigned int weight_age;
 
+	unsigned long (*get_score)(void *arg);
+	void *get_score_arg;
+
 /* private: */
 	/* For throughput estimation */
 	unsigned long total_charged_sz;
@@ -179,6 +195,9 @@ struct damos_quota {
 	/* For prioritization */
 	unsigned long histogram[DAMOS_MAX_SCORE + 1];
 	unsigned int min_score;
+
+	/* For feedback loop */
+	unsigned long esz_bp;
 };
 
 /**
diff --git a/mm/damon/core.c b/mm/damon/core.c
index c451e7dfcd64..4d4e4ebbbb2a 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1086,26 +1086,73 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 	}
 }
 
-/* Shouldn't be called if quota->ms and quota->sz are zero */
+/*
+ * damon_feed_loop_next_input() - get next input to achieve a target score.
+ * @last_input	The last input.
+ * @score	Current score that made with @last_input.
+ *
+ * Calculate next input to achieve the target score, based on the last input
+ * and current score.  Assuming the input and the score are positively
+ * proportional, calculate how much compensation should be added to or
+ * subtracted from the last input as a proportion of the last input.  Avoid
+ * next input always being zero by setting it non-zero always.  In short form
+ * (assuming support of float and signed calculations), the algorithm is as
+ * below.
+ *
+ * next_input = max(last_input * ((goal - current) / goal + 1), 1)
+ *
+ * For simple implementation, we assume the target score is always 10,000.  The
+ * caller should adjust @score for this.
+ *
+ * Returns next input that assumed to achieve the target score.
+ */
+static unsigned long damon_feed_loop_next_input(unsigned long last_input,
+		unsigned long score)
+{
+	const unsigned long goal = 10000;
+	unsigned long score_goal_diff = max(goal, score) - min(goal, score);
+	unsigned long score_goal_diff_bp = score_goal_diff * 10000 / goal;
+	unsigned long compensation = last_input * score_goal_diff_bp / 10000;
+	/* Set minimum input as 10000 to avoid compensation be zero */
+	const unsigned long min_input = 10000;
+
+	if (goal > score)
+		return last_input + compensation;
+	if (last_input > compensation + min_input)
+		return last_input - compensation;
+	return min_input;
+}
+
+/* Shouldn't be called if quota->ms, quota->sz, and quota->get_score unset */
 static void damos_set_effective_quota(struct damos_quota *quota)
 {
 	unsigned long throughput;
 	unsigned long esz;
 
-	if (!quota->ms) {
+	if (!quota->ms && !quota->get_score) {
 		quota->esz = quota->sz;
 		return;
 	}
 
-	if (quota->total_charged_ns)
-		throughput = quota->total_charged_sz * 1000000 /
-			quota->total_charged_ns;
-	else
-		throughput = PAGE_SIZE * 1024;
-	esz = throughput * quota->ms;
+	if (quota->get_score) {
+		quota->esz_bp = damon_feed_loop_next_input(
+				max(quota->esz_bp, 10000UL),
+				quota->get_score(quota->get_score_arg));
+		esz = quota->esz_bp / 10000;
+	}
+
+	if (quota->ms) {
+		if (quota->total_charged_ns)
+			throughput = quota->total_charged_sz * 1000000 /
+				quota->total_charged_ns;
+		else
+			throughput = PAGE_SIZE * 1024;
+		esz = min(throughput * quota->ms, esz);
+	}
 
 	if (quota->sz && quota->sz < esz)
 		esz = quota->sz;
+
 	quota->esz = esz;
 }
 
@@ -1117,7 +1164,7 @@ static void damos_adjust_quota(struct damon_ctx *c, struct damos *s)
 	unsigned long cumulated_sz;
 	unsigned int score, max_score = 0;
 
-	if (!quota->ms && !quota->sz)
+	if (!quota->ms && !quota->sz && !quota->get_score)
 		return;
 
 	/* New charge window starts */
-- 
2.34.1

[RFC PATCH 1/8] mm/damon/core: implement goal-oriented feedback-driven quota auto-tuning

[SeongJae Park]

Users can effectively control the upper-most aggressiveness of DAMOS
schemes using the quota feature.  The quota provides best result under
the aggressiveness limit since it prioritizes regions based on the
access pattern.  Finding the best value, which could depend on dynamic
characteristics of the system and the workloads, is still challenging,
though.

Implement a simple feedback-driven tuning mechanism and use it for
automatic tuning of DAMOS quota.  The implementation allows users to
provide the feedback by setting a feedback score returning callback
function.  Then DAMOS periodically adjusts the quota based on the return
value of the function calls.

Note that the absolute-value based time/size quotas still work as the
maximum hard limit of the scheme's aggressiveness.  The feedback-driven
auto-tuned quota is applied only if it is not exceeding the manually set
maximum limit.  Same for the scheme-target access pattern and filters
like other features.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/damon.h | 19 +++++++++++++
 mm/damon/core.c       | 65 +++++++++++++++++++++++++++++++++++++------
 2 files changed, 75 insertions(+), 9 deletions(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 89f5ca041848..9d46e0b39456 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -136,6 +136,8 @@ enum damos_action {
  * @weight_nr_accesses:	Weight of the region's nr_accesses for prioritization.
  * @weight_age:		Weight of the region's age for prioritization.
  *
+ * @get_score:		Feedback function for self-tuning quota.
+ *
  * To avoid consuming too much CPU time or IO resources for applying the
  * &struct damos->action to large memory, DAMON allows users to set time and/or
  * size quotas.  The quotas can be set by writing non-zero values to &ms and
@@ -153,6 +155,17 @@ enum damos_action {
  * You could customize the prioritization logic by setting &weight_sz,
  * &weight_nr_accesses, and &weight_age, because monitoring operations are
  * encouraged to respect those.
+ *
+ * If @get_score function pointer is set, DAMON calls it back and get the
+ * return value of it for every @reset_interval.  Then, DAMON adjusts the
+ * effective quota using the return value as a feedback score to the current
+ * quota, using its internal feedback loop algorithm.
+ *
+ * The feedback loop algorithem assumes the quota input and the feedback score
+ * output are in a positive proportional relationship, and the goal of the
+ * tuning is getting the feedback screo value of 10,000.  If @ms and/or @sz are
+ * set together, those work as a hard limit quota.  If neither @ms nor @sz are
+ * set, the mechanism starts from the quota of one byte.
  */
 struct damos_quota {
 	unsigned long ms;
@@ -163,6 +176,9 @@ struct damos_quota {
 	unsigned int weight_nr_accesses;
 	unsigned int weight_age;
 
+	unsigned long (*get_score)(void *arg);
+	void *get_score_arg;
+
 /* private: */
 	/* For throughput estimation */
 	unsigned long total_charged_sz;
@@ -179,6 +195,9 @@ struct damos_quota {
 	/* For prioritization */
 	unsigned long histogram[DAMOS_MAX_SCORE + 1];
 	unsigned int min_score;
+
+	/* For feedback loop */
+	unsigned long esz_bp;
 };
 
 /**
diff --git a/mm/damon/core.c b/mm/damon/core.c
index c451e7dfcd64..4d4e4ebbbb2a 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1086,26 +1086,73 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 	}
 }
 
-/* Shouldn't be called if quota->ms and quota->sz are zero */
+/*
+ * damon_feed_loop_next_input() - get next input to achieve a target score.
+ * @last_input	The last input.
+ * @score	Current score that made with @last_input.
+ *
+ * Calculate next input to achieve the target score, based on the last input
+ * and current score.  Assuming the input and the score are positively
+ * proportional, calculate how much compensation should be added to or
+ * subtracted from the last input as a proportion of the last input.  Avoid
+ * next input always being zero by setting it non-zero always.  In short form
+ * (assuming support of float and signed calculations), the algorithm is as
+ * below.
+ *
+ * next_input = max(last_input * ((goal - current) / goal + 1), 1)
+ *
+ * For simple implementation, we assume the target score is always 10,000.  The
+ * caller should adjust @score for this.
+ *
+ * Returns next input that assumed to achieve the target score.
+ */
+static unsigned long damon_feed_loop_next_input(unsigned long last_input,
+		unsigned long score)
+{
+	const unsigned long goal = 10000;
+	unsigned long score_goal_diff = max(goal, score) - min(goal, score);
+	unsigned long score_goal_diff_bp = score_goal_diff * 10000 / goal;
+	unsigned long compensation = last_input * score_goal_diff_bp / 10000;
+	/* Set minimum input as 10000 to avoid compensation be zero */
+	const unsigned long min_input = 10000;
+
+	if (goal > score)
+		return last_input + compensation;
+	if (last_input > compensation + min_input)
+		return last_input - compensation;
+	return min_input;
+}
+
+/* Shouldn't be called if quota->ms, quota->sz, and quota->get_score unset */
 static void damos_set_effective_quota(struct damos_quota *quota)
 {
 	unsigned long throughput;
 	unsigned long esz;
 
-	if (!quota->ms) {
+	if (!quota->ms && !quota->get_score) {
 		quota->esz = quota->sz;
 		return;
 	}
 
-	if (quota->total_charged_ns)
-		throughput = quota->total_charged_sz * 1000000 /
-			quota->total_charged_ns;
-	else
-		throughput = PAGE_SIZE * 1024;
-	esz = throughput * quota->ms;
+	if (quota->get_score) {
+		quota->esz_bp = damon_feed_loop_next_input(
+				max(quota->esz_bp, 10000UL),
+				quota->get_score(quota->get_score_arg));
+		esz = quota->esz_bp / 10000;
+	}
+
+	if (quota->ms) {
+		if (quota->total_charged_ns)
+			throughput = quota->total_charged_sz * 1000000 /
+				quota->total_charged_ns;
+		else
+			throughput = PAGE_SIZE * 1024;
+		esz = min(throughput * quota->ms, esz);
+	}
 
 	if (quota->sz && quota->sz < esz)
 		esz = quota->sz;
+
 	quota->esz = esz;
 }
 
@@ -1117,7 +1164,7 @@ static void damos_adjust_quota(struct damon_ctx *c, struct damos *s)
 	unsigned long cumulated_sz;
 	unsigned int score, max_score = 0;
 
-	if (!quota->ms && !quota->sz)
+	if (!quota->ms && !quota->sz && !quota->get_score)
 		return;
 
 	/* New charge window starts */
-- 
2.34.1

[RFC PATCH 2/8] mm/damon/sysfs-schemes: implement scheme quota goals directory

[SeongJae Park]

Implement DAMON sysfs directories and files for the goals of DAMOS
quota.  It allows users set multiple goals for their aim, with target
values.  It further allows users to enter the current score value as a
feedback for DAMOS.  Following commit will connect the user inputs to
DAMOS quota auto-tuning.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 224 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 221 insertions(+), 3 deletions(-)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index be667236b8e6..d3b57348f07b 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -812,6 +812,203 @@ static const struct kobj_type damon_sysfs_watermarks_ktype = {
 	.default_groups = damon_sysfs_watermarks_groups,
 };
 
+/*
+ * quota goal directory
+ */
+
+struct damos_sysfs_quota_goal {
+	struct kobject kobj;
+	unsigned long target_value;
+	unsigned long current_value;
+};
+
+static struct damos_sysfs_quota_goal *damos_sysfs_quota_goal_alloc(void)
+{
+	return kzalloc(sizeof(struct damos_sysfs_quota_goal), GFP_KERNEL);
+}
+
+static ssize_t target_value_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damos_sysfs_quota_goal *goal = container_of(kobj, struct
+			damos_sysfs_quota_goal, kobj);
+
+	return sysfs_emit(buf, "%lu\n", goal->target_value);
+}
+
+static ssize_t target_value_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damos_sysfs_quota_goal *goal = container_of(kobj, struct
+			damos_sysfs_quota_goal, kobj);
+	int err = kstrtoul(buf, 0, &goal->target_value);
+
+	return err ? err : count;
+}
+
+static ssize_t current_value_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damos_sysfs_quota_goal *goal = container_of(kobj, struct
+			damos_sysfs_quota_goal, kobj);
+
+	return sysfs_emit(buf, "%lu\n", goal->current_value);
+}
+
+static ssize_t current_value_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damos_sysfs_quota_goal *goal = container_of(kobj, struct
+			damos_sysfs_quota_goal, kobj);
+	int err = kstrtoul(buf, 0, &goal->current_value);
+
+	/* feed callback should check existence of this file and read value */
+	return err ? err : count;
+}
+
+static void damos_sysfs_quota_goal_release(struct kobject *kobj)
+{
+	/* or, notify this release to the feed callback */
+	kfree(container_of(kobj, struct damos_sysfs_quota_goal, kobj));
+}
+
+static struct kobj_attribute damos_sysfs_quota_goal_target_value_attr =
+		__ATTR_RW_MODE(target_value, 0600);
+
+static struct kobj_attribute damos_sysfs_quota_goal_current_value_attr =
+		__ATTR_RW_MODE(current_value, 0600);
+
+static struct attribute *damos_sysfs_quota_goal_attrs[] = {
+	&damos_sysfs_quota_goal_target_value_attr.attr,
+	&damos_sysfs_quota_goal_current_value_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damos_sysfs_quota_goal);
+
+static const struct kobj_type damos_sysfs_quota_goal_ktype = {
+	.release = damos_sysfs_quota_goal_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damos_sysfs_quota_goal_groups,
+};
+
+/*
+ * quota goals directory
+ */
+
+struct damos_sysfs_quota_goals {
+	struct kobject kobj;
+	struct damos_sysfs_quota_goal **goals_arr;	/* counted by nr */
+	int nr;
+};
+
+static struct damos_sysfs_quota_goals *damos_sysfs_quota_goals_alloc(void)
+{
+	return kzalloc(sizeof(struct damos_sysfs_quota_goals), GFP_KERNEL);
+}
+
+static void damos_sysfs_quota_goals_rm_dirs(
+		struct damos_sysfs_quota_goals *goals)
+{
+	struct damos_sysfs_quota_goal **goals_arr = goals->goals_arr;
+	int i;
+
+	for (i = 0; i < goals->nr; i++)
+		kobject_put(&goals_arr[i]->kobj);
+	goals->nr = 0;
+	kfree(goals_arr);
+	goals->goals_arr = NULL;
+}
+
+static int damos_sysfs_quota_goals_add_dirs(
+		struct damos_sysfs_quota_goals *goals, int nr_goals)
+{
+	struct damos_sysfs_quota_goal **goals_arr, *goal;
+	int err, i;
+
+	damos_sysfs_quota_goals_rm_dirs(goals);
+	if (!nr_goals)
+		return 0;
+
+	goals_arr = kmalloc_array(nr_goals, sizeof(*goals_arr),
+			GFP_KERNEL | __GFP_NOWARN);
+	if (!goals_arr)
+		return -ENOMEM;
+	goals->goals_arr = goals_arr;
+
+	for (i = 0; i < nr_goals; i++) {
+		goal = damos_sysfs_quota_goal_alloc();
+		if (!goal) {
+			damos_sysfs_quota_goals_rm_dirs(goals);
+			return -ENOMEM;
+		}
+
+		err = kobject_init_and_add(&goal->kobj,
+				&damos_sysfs_quota_goal_ktype, &goals->kobj,
+				"%d", i);
+		if (err) {
+			kobject_put(&goal->kobj);
+			damos_sysfs_quota_goals_rm_dirs(goals);
+			return err;
+		}
+
+		goals_arr[i] = goal;
+		goals->nr++;
+	}
+	return 0;
+}
+
+static ssize_t nr_goals_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damos_sysfs_quota_goals *goals = container_of(kobj,
+			struct damos_sysfs_quota_goals, kobj);
+
+	return sysfs_emit(buf, "%d\n", goals->nr);
+}
+
+static ssize_t nr_goals_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damos_sysfs_quota_goals *goals;
+	int nr, err = kstrtoint(buf, 0, &nr);
+
+	if (err)
+		return err;
+	if (nr < 0)
+		return -EINVAL;
+
+	goals = container_of(kobj, struct damos_sysfs_quota_goals, kobj);
+
+	if (!mutex_trylock(&damon_sysfs_lock))
+		return -EBUSY;
+	err = damos_sysfs_quota_goals_add_dirs(goals, nr);
+	mutex_unlock(&damon_sysfs_lock);
+	if (err)
+		return err;
+
+	return count;
+}
+
+static void damos_sysfs_quota_goals_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damos_sysfs_quota_goals, kobj));
+}
+
+static struct kobj_attribute damos_sysfs_quota_goals_nr_attr =
+		__ATTR_RW_MODE(nr_goals, 0600);
+
+static struct attribute *damos_sysfs_quota_goals_attrs[] = {
+	&damos_sysfs_quota_goals_nr_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damos_sysfs_quota_goals);
+
+static const struct kobj_type damos_sysfs_quota_goals_ktype = {
+	.release = damos_sysfs_quota_goals_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damos_sysfs_quota_goals_groups,
+};
+
 /*
  * scheme/weights directory
  */
@@ -930,6 +1127,7 @@ static const struct kobj_type damon_sysfs_weights_ktype = {
 struct damon_sysfs_quotas {
 	struct kobject kobj;
 	struct damon_sysfs_weights *weights;
+	struct damos_sysfs_quota_goals *goals;
 	unsigned long ms;
 	unsigned long sz;
 	unsigned long reset_interval_ms;
@@ -943,6 +1141,7 @@ static struct damon_sysfs_quotas *damon_sysfs_quotas_alloc(void)
 static int damon_sysfs_quotas_add_dirs(struct damon_sysfs_quotas *quotas)
 {
 	struct damon_sysfs_weights *weights;
+	struct damos_sysfs_quota_goals *goals;
 	int err;
 
 	weights = damon_sysfs_weights_alloc(0, 0, 0);
@@ -951,16 +1150,35 @@ static int damon_sysfs_quotas_add_dirs(struct damon_sysfs_quotas *quotas)
 
 	err = kobject_init_and_add(&weights->kobj, &damon_sysfs_weights_ktype,
 			&quotas->kobj, "weights");
-	if (err)
+	if (err) {
 		kobject_put(&weights->kobj);
-	else
-		quotas->weights = weights;
+		return err;
+	}
+	quotas->weights = weights;
+
+	goals = damos_sysfs_quota_goals_alloc();
+	if (!goals) {
+		kobject_put(&weights->kobj);
+		return -ENOMEM;
+	}
+	err = kobject_init_and_add(&goals->kobj,
+			&damos_sysfs_quota_goals_ktype, &quotas->kobj,
+			"goals");
+	if (err) {
+		kobject_put(&weights->kobj);
+		kobject_put(&goals->kobj);
+	} else {
+		quotas->goals = goals;
+	}
+
 	return err;
 }
 
 static void damon_sysfs_quotas_rm_dirs(struct damon_sysfs_quotas *quotas)
 {
 	kobject_put(&quotas->weights->kobj);
+	damos_sysfs_quota_goals_rm_dirs(quotas->goals);
+	kobject_put(&quotas->goals->kobj);
 }
 
 static ssize_t ms_show(struct kobject *kobj, struct kobj_attribute *attr,
-- 
2.34.1

[RFC PATCH 2/8] mm/damon/sysfs-schemes: implement scheme quota goals directory

[SeongJae Park]

Implement DAMON sysfs directories and files for the goals of DAMOS
quota.  It allows users set multiple goals for their aim, with target
values.  It further allows users to enter the current score value as a
feedback for DAMOS.  Following commit will connect the user inputs to
DAMOS quota auto-tuning.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 224 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 221 insertions(+), 3 deletions(-)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index be667236b8e6..d3b57348f07b 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -812,6 +812,203 @@ static const struct kobj_type damon_sysfs_watermarks_ktype = {
 	.default_groups = damon_sysfs_watermarks_groups,
 };
 
+/*
+ * quota goal directory
+ */
+
+struct damos_sysfs_quota_goal {
+	struct kobject kobj;
+	unsigned long target_value;
+	unsigned long current_value;
+};
+
+static struct damos_sysfs_quota_goal *damos_sysfs_quota_goal_alloc(void)
+{
+	return kzalloc(sizeof(struct damos_sysfs_quota_goal), GFP_KERNEL);
+}
+
+static ssize_t target_value_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damos_sysfs_quota_goal *goal = container_of(kobj, struct
+			damos_sysfs_quota_goal, kobj);
+
+	return sysfs_emit(buf, "%lu\n", goal->target_value);
+}
+
+static ssize_t target_value_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damos_sysfs_quota_goal *goal = container_of(kobj, struct
+			damos_sysfs_quota_goal, kobj);
+	int err = kstrtoul(buf, 0, &goal->target_value);
+
+	return err ? err : count;
+}
+
+static ssize_t current_value_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damos_sysfs_quota_goal *goal = container_of(kobj, struct
+			damos_sysfs_quota_goal, kobj);
+
+	return sysfs_emit(buf, "%lu\n", goal->current_value);
+}
+
+static ssize_t current_value_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damos_sysfs_quota_goal *goal = container_of(kobj, struct
+			damos_sysfs_quota_goal, kobj);
+	int err = kstrtoul(buf, 0, &goal->current_value);
+
+	/* feed callback should check existence of this file and read value */
+	return err ? err : count;
+}
+
+static void damos_sysfs_quota_goal_release(struct kobject *kobj)
+{
+	/* or, notify this release to the feed callback */
+	kfree(container_of(kobj, struct damos_sysfs_quota_goal, kobj));
+}
+
+static struct kobj_attribute damos_sysfs_quota_goal_target_value_attr =
+		__ATTR_RW_MODE(target_value, 0600);
+
+static struct kobj_attribute damos_sysfs_quota_goal_current_value_attr =
+		__ATTR_RW_MODE(current_value, 0600);
+
+static struct attribute *damos_sysfs_quota_goal_attrs[] = {
+	&damos_sysfs_quota_goal_target_value_attr.attr,
+	&damos_sysfs_quota_goal_current_value_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damos_sysfs_quota_goal);
+
+static const struct kobj_type damos_sysfs_quota_goal_ktype = {
+	.release = damos_sysfs_quota_goal_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damos_sysfs_quota_goal_groups,
+};
+
+/*
+ * quota goals directory
+ */
+
+struct damos_sysfs_quota_goals {
+	struct kobject kobj;
+	struct damos_sysfs_quota_goal **goals_arr;	/* counted by nr */
+	int nr;
+};
+
+static struct damos_sysfs_quota_goals *damos_sysfs_quota_goals_alloc(void)
+{
+	return kzalloc(sizeof(struct damos_sysfs_quota_goals), GFP_KERNEL);
+}
+
+static void damos_sysfs_quota_goals_rm_dirs(
+		struct damos_sysfs_quota_goals *goals)
+{
+	struct damos_sysfs_quota_goal **goals_arr = goals->goals_arr;
+	int i;
+
+	for (i = 0; i < goals->nr; i++)
+		kobject_put(&goals_arr[i]->kobj);
+	goals->nr = 0;
+	kfree(goals_arr);
+	goals->goals_arr = NULL;
+}
+
+static int damos_sysfs_quota_goals_add_dirs(
+		struct damos_sysfs_quota_goals *goals, int nr_goals)
+{
+	struct damos_sysfs_quota_goal **goals_arr, *goal;
+	int err, i;
+
+	damos_sysfs_quota_goals_rm_dirs(goals);
+	if (!nr_goals)
+		return 0;
+
+	goals_arr = kmalloc_array(nr_goals, sizeof(*goals_arr),
+			GFP_KERNEL | __GFP_NOWARN);
+	if (!goals_arr)
+		return -ENOMEM;
+	goals->goals_arr = goals_arr;
+
+	for (i = 0; i < nr_goals; i++) {
+		goal = damos_sysfs_quota_goal_alloc();
+		if (!goal) {
+			damos_sysfs_quota_goals_rm_dirs(goals);
+			return -ENOMEM;
+		}
+
+		err = kobject_init_and_add(&goal->kobj,
+				&damos_sysfs_quota_goal_ktype, &goals->kobj,
+				"%d", i);
+		if (err) {
+			kobject_put(&goal->kobj);
+			damos_sysfs_quota_goals_rm_dirs(goals);
+			return err;
+		}
+
+		goals_arr[i] = goal;
+		goals->nr++;
+	}
+	return 0;
+}
+
+static ssize_t nr_goals_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damos_sysfs_quota_goals *goals = container_of(kobj,
+			struct damos_sysfs_quota_goals, kobj);
+
+	return sysfs_emit(buf, "%d\n", goals->nr);
+}
+
+static ssize_t nr_goals_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damos_sysfs_quota_goals *goals;
+	int nr, err = kstrtoint(buf, 0, &nr);
+
+	if (err)
+		return err;
+	if (nr < 0)
+		return -EINVAL;
+
+	goals = container_of(kobj, struct damos_sysfs_quota_goals, kobj);
+
+	if (!mutex_trylock(&damon_sysfs_lock))
+		return -EBUSY;
+	err = damos_sysfs_quota_goals_add_dirs(goals, nr);
+	mutex_unlock(&damon_sysfs_lock);
+	if (err)
+		return err;
+
+	return count;
+}
+
+static void damos_sysfs_quota_goals_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damos_sysfs_quota_goals, kobj));
+}
+
+static struct kobj_attribute damos_sysfs_quota_goals_nr_attr =
+		__ATTR_RW_MODE(nr_goals, 0600);
+
+static struct attribute *damos_sysfs_quota_goals_attrs[] = {
+	&damos_sysfs_quota_goals_nr_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damos_sysfs_quota_goals);
+
+static const struct kobj_type damos_sysfs_quota_goals_ktype = {
+	.release = damos_sysfs_quota_goals_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damos_sysfs_quota_goals_groups,
+};
+
 /*
  * scheme/weights directory
  */
@@ -930,6 +1127,7 @@ static const struct kobj_type damon_sysfs_weights_ktype = {
 struct damon_sysfs_quotas {
 	struct kobject kobj;
 	struct damon_sysfs_weights *weights;
+	struct damos_sysfs_quota_goals *goals;
 	unsigned long ms;
 	unsigned long sz;
 	unsigned long reset_interval_ms;
@@ -943,6 +1141,7 @@ static struct damon_sysfs_quotas *damon_sysfs_quotas_alloc(void)
 static int damon_sysfs_quotas_add_dirs(struct damon_sysfs_quotas *quotas)
 {
 	struct damon_sysfs_weights *weights;
+	struct damos_sysfs_quota_goals *goals;
 	int err;
 
 	weights = damon_sysfs_weights_alloc(0, 0, 0);
@@ -951,16 +1150,35 @@ static int damon_sysfs_quotas_add_dirs(struct damon_sysfs_quotas *quotas)
 
 	err = kobject_init_and_add(&weights->kobj, &damon_sysfs_weights_ktype,
 			&quotas->kobj, "weights");
-	if (err)
+	if (err) {
 		kobject_put(&weights->kobj);
-	else
-		quotas->weights = weights;
+		return err;
+	}
+	quotas->weights = weights;
+
+	goals = damos_sysfs_quota_goals_alloc();
+	if (!goals) {
+		kobject_put(&weights->kobj);
+		return -ENOMEM;
+	}
+	err = kobject_init_and_add(&goals->kobj,
+			&damos_sysfs_quota_goals_ktype, &quotas->kobj,
+			"goals");
+	if (err) {
+		kobject_put(&weights->kobj);
+		kobject_put(&goals->kobj);
+	} else {
+		quotas->goals = goals;
+	}
+
 	return err;
 }
 
 static void damon_sysfs_quotas_rm_dirs(struct damon_sysfs_quotas *quotas)
 {
 	kobject_put(&quotas->weights->kobj);
+	damos_sysfs_quota_goals_rm_dirs(quotas->goals);
+	kobject_put(&quotas->goals->kobj);
 }
 
 static ssize_t ms_show(struct kobject *kobj, struct kobj_attribute *attr,
-- 
2.34.1

[RFC PATCH 3/8] mm/damon/sysfs-schemes: commit damos quota goals user input to DAMOS quota auto-tuning

[SeongJae Park]

Make DAMON sysfs interface to read the DAMOS quota goals user input and
pass it to DAMOS so that the input can be used for the quota
auto-tuning.  The committing is made for initial starting of DAMON, and
online input updates that can be done via 'commit' input to the
kdamond's 'state' file.  That is, the user should periodically write
'current_value' files under goal directories and write 'commit' command
to the 'state' file.

Note that the interface is supporting multiple goals while the core
logic supports only one goal.  DAMON sysfs interface passes only best
feedback among the given inputs, to avoid making DAMOS too aggressive.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index d3b57348f07b..10d8678e48ea 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1860,6 +1860,34 @@ static int damon_sysfs_set_scheme_filters(struct damos *scheme,
 	return 0;
 }
 
+static unsigned long damos_sysfs_get_quota_score(void *arg)
+{
+	return (unsigned long)arg;
+}
+
+static void damos_sysfs_set_quota_score(
+		struct damos_sysfs_quota_goals *sysfs_goals,
+		struct damos_quota *quota)
+{
+	struct damos_sysfs_quota_goal *sysfs_goal;
+	int i;
+
+	quota->get_score = NULL;
+	quota->get_score_arg = (void *)0;
+	for (i = 0; i < sysfs_goals->nr; i++) {
+		sysfs_goal = sysfs_goals->goals_arr[i];
+		if (!sysfs_goal->target_value)
+			continue;
+
+		/* Higher score makes scheme less aggressive */
+		quota->get_score_arg = (void *)max(
+				(unsigned long)quota->get_score_arg,
+				sysfs_goal->current_value * 10000 /
+				sysfs_goal->target_value);
+		quota->get_score = damos_sysfs_get_quota_score;
+	}
+}
+
 static struct damos *damon_sysfs_mk_scheme(
 		struct damon_sysfs_scheme *sysfs_scheme)
 {
@@ -1897,6 +1925,8 @@ static struct damos *damon_sysfs_mk_scheme(
 		.low = sysfs_wmarks->low,
 	};
 
+	damos_sysfs_set_quota_score(sysfs_quotas->goals, &quota);
+
 	scheme = damon_new_scheme(&pattern, sysfs_scheme->action,
 			sysfs_scheme->apply_interval_us, &quota, &wmarks);
 	if (!scheme)
@@ -1937,6 +1967,8 @@ static void damon_sysfs_update_scheme(struct damos *scheme,
 	scheme->quota.weight_nr_accesses = sysfs_weights->nr_accesses;
 	scheme->quota.weight_age = sysfs_weights->age;
 
+	damos_sysfs_set_quota_score(sysfs_quotas->goals, &scheme->quota);
+
 	scheme->wmarks.metric = sysfs_wmarks->metric;
 	scheme->wmarks.interval = sysfs_wmarks->interval_us;
 	scheme->wmarks.high = sysfs_wmarks->high;
-- 
2.34.1

[RFC PATCH 3/8] mm/damon/sysfs-schemes: commit damos quota goals user input to DAMOS quota auto-tuning

[SeongJae Park]

Make DAMON sysfs interface to read the DAMOS quota goals user input and
pass it to DAMOS so that the input can be used for the quota
auto-tuning.  The committing is made for initial starting of DAMON, and
online input updates that can be done via 'commit' input to the
kdamond's 'state' file.  That is, the user should periodically write
'current_value' files under goal directories and write 'commit' command
to the 'state' file.

Note that the interface is supporting multiple goals while the core
logic supports only one goal.  DAMON sysfs interface passes only best
feedback among the given inputs, to avoid making DAMOS too aggressive.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index d3b57348f07b..10d8678e48ea 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1860,6 +1860,34 @@ static int damon_sysfs_set_scheme_filters(struct damos *scheme,
 	return 0;
 }
 
+static unsigned long damos_sysfs_get_quota_score(void *arg)
+{
+	return (unsigned long)arg;
+}
+
+static void damos_sysfs_set_quota_score(
+		struct damos_sysfs_quota_goals *sysfs_goals,
+		struct damos_quota *quota)
+{
+	struct damos_sysfs_quota_goal *sysfs_goal;
+	int i;
+
+	quota->get_score = NULL;
+	quota->get_score_arg = (void *)0;
+	for (i = 0; i < sysfs_goals->nr; i++) {
+		sysfs_goal = sysfs_goals->goals_arr[i];
+		if (!sysfs_goal->target_value)
+			continue;
+
+		/* Higher score makes scheme less aggressive */
+		quota->get_score_arg = (void *)max(
+				(unsigned long)quota->get_score_arg,
+				sysfs_goal->current_value * 10000 /
+				sysfs_goal->target_value);
+		quota->get_score = damos_sysfs_get_quota_score;
+	}
+}
+
 static struct damos *damon_sysfs_mk_scheme(
 		struct damon_sysfs_scheme *sysfs_scheme)
 {
@@ -1897,6 +1925,8 @@ static struct damos *damon_sysfs_mk_scheme(
 		.low = sysfs_wmarks->low,
 	};
 
+	damos_sysfs_set_quota_score(sysfs_quotas->goals, &quota);
+
 	scheme = damon_new_scheme(&pattern, sysfs_scheme->action,
 			sysfs_scheme->apply_interval_us, &quota, &wmarks);
 	if (!scheme)
@@ -1937,6 +1967,8 @@ static void damon_sysfs_update_scheme(struct damos *scheme,
 	scheme->quota.weight_nr_accesses = sysfs_weights->nr_accesses;
 	scheme->quota.weight_age = sysfs_weights->age;
 
+	damos_sysfs_set_quota_score(sysfs_quotas->goals, &scheme->quota);
+
 	scheme->wmarks.metric = sysfs_wmarks->metric;
 	scheme->wmarks.interval = sysfs_wmarks->interval_us;
 	scheme->wmarks.high = sysfs_wmarks->high;
-- 
2.34.1

[RFC PATCH 4/8] mm/damon/sysfs-schemes: implement a command for scheme quota goals only commit

[SeongJae Park]

To update DAMOS quota goals, users need to enter 'commit' command to the
'state' file of the kdamond, which reads and commits not only the goals
but entire inputs.  It is inefficient.  Implement yet another 'state'
file input command for reading and committing only the scheme quota
goals, namely 'commit_schemes_quota_goals'.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-common.h  |  3 +++
 mm/damon/sysfs-schemes.c | 16 ++++++++++++++++
 mm/damon/sysfs.c         | 27 +++++++++++++++++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/mm/damon/sysfs-common.h b/mm/damon/sysfs-common.h
index 5ff081226e28..4c37a166eb81 100644
--- a/mm/damon/sysfs-common.h
+++ b/mm/damon/sysfs-common.h
@@ -56,3 +56,6 @@ int damon_sysfs_schemes_update_regions_stop(struct damon_ctx *ctx);
 int damon_sysfs_schemes_clear_regions(
 		struct damon_sysfs_schemes *sysfs_schemes,
 		struct damon_ctx *ctx);
+
+void damos_sysfs_set_quota_scores(struct damon_sysfs_schemes *sysfs_schemes,
+		struct damon_ctx *ctx);
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 10d8678e48ea..273fb7862fce 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1888,6 +1888,22 @@ static void damos_sysfs_set_quota_score(
 	}
 }
 
+void damos_sysfs_set_quota_scores(struct damon_sysfs_schemes *sysfs_schemes,
+		struct damon_ctx *ctx)
+{
+	struct damos *scheme;
+	int i = 0;
+
+	damon_for_each_scheme(scheme, ctx) {
+		struct damon_sysfs_scheme *sysfs_scheme;
+
+		sysfs_scheme = sysfs_schemes->schemes_arr[i];
+		damos_sysfs_set_quota_score(sysfs_scheme->quotas->goals,
+				&scheme->quota);
+		i++;
+	}
+}
+
 static struct damos *damon_sysfs_mk_scheme(
 		struct damon_sysfs_scheme *sysfs_scheme)
 {
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 2d31390edfc0..f6952cec9f19 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -994,6 +994,11 @@ enum damon_sysfs_cmd {
 	DAMON_SYSFS_CMD_OFF,
 	/* @DAMON_SYSFS_CMD_COMMIT: Update kdamond inputs. */
 	DAMON_SYSFS_CMD_COMMIT,
+	/*
+	 * @DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS: Commit the quota goals
+	 * to DAMON.
+	 */
+	DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS,
 	/*
 	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS: Update scheme stats sysfs
 	 * files.
@@ -1025,6 +1030,7 @@ static const char * const damon_sysfs_cmd_strs[] = {
 	"on",
 	"off",
 	"commit",
+	"commit_schemes_quota_goals",
 	"update_schemes_stats",
 	"update_schemes_tried_bytes",
 	"update_schemes_tried_regions",
@@ -1351,6 +1357,24 @@ static int damon_sysfs_commit_input(struct damon_sysfs_kdamond *kdamond)
 			kdamond->contexts->contexts_arr[0]);
 }
 
+static int damon_sysfs_commit_schemes_quota_goals(
+		struct damon_sysfs_kdamond *sysfs_kdamond)
+{
+	struct damon_ctx *ctx;
+	struct damon_sysfs_context *sysfs_ctx;
+
+	if (!damon_sysfs_kdamond_running(sysfs_kdamond))
+		return -EINVAL;
+	/* TODO: Support multiple contexts per kdamond */
+	if (sysfs_kdamond->contexts->nr != 1)
+		return -EINVAL;
+
+	ctx = sysfs_kdamond->damon_ctx;
+	sysfs_ctx = sysfs_kdamond->contexts->contexts_arr[0];
+	damos_sysfs_set_quota_scores(sysfs_ctx->schemes, ctx);
+	return 0;
+}
+
 /*
  * damon_sysfs_cmd_request_callback() - DAMON callback for handling requests.
  * @c:		The DAMON context of the callback.
@@ -1379,6 +1403,9 @@ static int damon_sysfs_cmd_request_callback(struct damon_ctx *c, bool active)
 	case DAMON_SYSFS_CMD_COMMIT:
 		err = damon_sysfs_commit_input(kdamond);
 		break;
+	case DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS:
+		err = damon_sysfs_commit_schemes_quota_goals(kdamond);
+		break;
 	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES:
 		total_bytes_only = true;
 		fallthrough;
-- 
2.34.1

[RFC PATCH 4/8] mm/damon/sysfs-schemes: implement a command for scheme quota goals only commit

[SeongJae Park]

To update DAMOS quota goals, users need to enter 'commit' command to the
'state' file of the kdamond, which reads and commits not only the goals
but entire inputs.  It is inefficient.  Implement yet another 'state'
file input command for reading and committing only the scheme quota
goals, namely 'commit_schemes_quota_goals'.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-common.h  |  3 +++
 mm/damon/sysfs-schemes.c | 16 ++++++++++++++++
 mm/damon/sysfs.c         | 27 +++++++++++++++++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/mm/damon/sysfs-common.h b/mm/damon/sysfs-common.h
index 5ff081226e28..4c37a166eb81 100644
--- a/mm/damon/sysfs-common.h
+++ b/mm/damon/sysfs-common.h
@@ -56,3 +56,6 @@ int damon_sysfs_schemes_update_regions_stop(struct damon_ctx *ctx);
 int damon_sysfs_schemes_clear_regions(
 		struct damon_sysfs_schemes *sysfs_schemes,
 		struct damon_ctx *ctx);
+
+void damos_sysfs_set_quota_scores(struct damon_sysfs_schemes *sysfs_schemes,
+		struct damon_ctx *ctx);
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 10d8678e48ea..273fb7862fce 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1888,6 +1888,22 @@ static void damos_sysfs_set_quota_score(
 	}
 }
 
+void damos_sysfs_set_quota_scores(struct damon_sysfs_schemes *sysfs_schemes,
+		struct damon_ctx *ctx)
+{
+	struct damos *scheme;
+	int i = 0;
+
+	damon_for_each_scheme(scheme, ctx) {
+		struct damon_sysfs_scheme *sysfs_scheme;
+
+		sysfs_scheme = sysfs_schemes->schemes_arr[i];
+		damos_sysfs_set_quota_score(sysfs_scheme->quotas->goals,
+				&scheme->quota);
+		i++;
+	}
+}
+
 static struct damos *damon_sysfs_mk_scheme(
 		struct damon_sysfs_scheme *sysfs_scheme)
 {
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 2d31390edfc0..f6952cec9f19 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -994,6 +994,11 @@ enum damon_sysfs_cmd {
 	DAMON_SYSFS_CMD_OFF,
 	/* @DAMON_SYSFS_CMD_COMMIT: Update kdamond inputs. */
 	DAMON_SYSFS_CMD_COMMIT,
+	/*
+	 * @DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS: Commit the quota goals
+	 * to DAMON.
+	 */
+	DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS,
 	/*
 	 * @DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS: Update scheme stats sysfs
 	 * files.
@@ -1025,6 +1030,7 @@ static const char * const damon_sysfs_cmd_strs[] = {
 	"on",
 	"off",
 	"commit",
+	"commit_schemes_quota_goals",
 	"update_schemes_stats",
 	"update_schemes_tried_bytes",
 	"update_schemes_tried_regions",
@@ -1351,6 +1357,24 @@ static int damon_sysfs_commit_input(struct damon_sysfs_kdamond *kdamond)
 			kdamond->contexts->contexts_arr[0]);
 }
 
+static int damon_sysfs_commit_schemes_quota_goals(
+		struct damon_sysfs_kdamond *sysfs_kdamond)
+{
+	struct damon_ctx *ctx;
+	struct damon_sysfs_context *sysfs_ctx;
+
+	if (!damon_sysfs_kdamond_running(sysfs_kdamond))
+		return -EINVAL;
+	/* TODO: Support multiple contexts per kdamond */
+	if (sysfs_kdamond->contexts->nr != 1)
+		return -EINVAL;
+
+	ctx = sysfs_kdamond->damon_ctx;
+	sysfs_ctx = sysfs_kdamond->contexts->contexts_arr[0];
+	damos_sysfs_set_quota_scores(sysfs_ctx->schemes, ctx);
+	return 0;
+}
+
 /*
  * damon_sysfs_cmd_request_callback() - DAMON callback for handling requests.
  * @c:		The DAMON context of the callback.
@@ -1379,6 +1403,9 @@ static int damon_sysfs_cmd_request_callback(struct damon_ctx *c, bool active)
 	case DAMON_SYSFS_CMD_COMMIT:
 		err = damon_sysfs_commit_input(kdamond);
 		break;
+	case DAMON_SYSFS_CMD_COMMIT_SCHEMES_QUOTA_GOALS:
+		err = damon_sysfs_commit_schemes_quota_goals(kdamond);
+		break;
 	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES:
 		total_bytes_only = true;
 		fallthrough;
-- 
2.34.1

[RFC PATCH 5/8] mm/damon/core-test: add a unit test for the feedback loop algorithm

[SeongJae Park]

Implement a simple kunit test for testing the behavior of the core logic
of the goal-oriented feedback-driven DAMOS quota auto-tuning.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core-test.h | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h
index f405d79dc623..c2b8cb25a195 100644
--- a/mm/damon/core-test.h
+++ b/mm/damon/core-test.h
@@ -447,6 +447,37 @@ static void damos_test_filter_out(struct kunit *test)
 	damos_free_filter(f);
 }
 
+static void damon_test_feed_loop_next_input(struct kunit *test)
+{
+	unsigned long last_input = 900000, current_score = 200;
+
+	/*
+	 * If current score is lower than the goal, which is always 10,000
+	 * (read the comment on damon_feed_loop_next_input()'s comment), next
+	 * input should be higher than the last input.
+	 */
+	KUNIT_EXPECT_GT(test,
+			damon_feed_loop_next_input(last_input, current_score),
+			last_input);
+
+	/*
+	 * If current score is higher than the goal, next input should be lower
+	 * than the last input.
+	 */
+	current_score = 250000000;
+	KUNIT_EXPECT_LT(test,
+			damon_feed_loop_next_input(last_input, current_score),
+			last_input);
+
+	/*
+	 * The next input depends on the distance between the current score and
+	 * the goal
+	 */
+	KUNIT_EXPECT_GT(test,
+			damon_feed_loop_next_input(last_input, 200),
+			damon_feed_loop_next_input(last_input, 2000));
+}
+
 static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damon_test_target),
 	KUNIT_CASE(damon_test_regions),
@@ -463,6 +494,7 @@ static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damon_test_moving_sum),
 	KUNIT_CASE(damos_test_new_filter),
 	KUNIT_CASE(damos_test_filter_out),
+	KUNIT_CASE(damon_test_feed_loop_next_input),
 	{},
 };
 
-- 
2.34.1

[RFC PATCH 5/8] mm/damon/core-test: add a unit test for the feedback loop algorithm

[SeongJae Park]

Implement a simple kunit test for testing the behavior of the core logic
of the goal-oriented feedback-driven DAMOS quota auto-tuning.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core-test.h | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h
index f405d79dc623..c2b8cb25a195 100644
--- a/mm/damon/core-test.h
+++ b/mm/damon/core-test.h
@@ -447,6 +447,37 @@ static void damos_test_filter_out(struct kunit *test)
 	damos_free_filter(f);
 }
 
+static void damon_test_feed_loop_next_input(struct kunit *test)
+{
+	unsigned long last_input = 900000, current_score = 200;
+
+	/*
+	 * If current score is lower than the goal, which is always 10,000
+	 * (read the comment on damon_feed_loop_next_input()'s comment), next
+	 * input should be higher than the last input.
+	 */
+	KUNIT_EXPECT_GT(test,
+			damon_feed_loop_next_input(last_input, current_score),
+			last_input);
+
+	/*
+	 * If current score is higher than the goal, next input should be lower
+	 * than the last input.
+	 */
+	current_score = 250000000;
+	KUNIT_EXPECT_LT(test,
+			damon_feed_loop_next_input(last_input, current_score),
+			last_input);
+
+	/*
+	 * The next input depends on the distance between the current score and
+	 * the goal
+	 */
+	KUNIT_EXPECT_GT(test,
+			damon_feed_loop_next_input(last_input, 200),
+			damon_feed_loop_next_input(last_input, 2000));
+}
+
 static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damon_test_target),
 	KUNIT_CASE(damon_test_regions),
@@ -463,6 +494,7 @@ static struct kunit_case damon_test_cases[] = {
 	KUNIT_CASE(damon_test_moving_sum),
 	KUNIT_CASE(damos_test_new_filter),
 	KUNIT_CASE(damos_test_filter_out),
+	KUNIT_CASE(damon_test_feed_loop_next_input),
 	{},
 };
 
-- 
2.34.1

[RFC PATCH 6/8] selftests/damon: test quota goals directory

[SeongJae Park]

Add DAMON selftests for testing creation/existence of quota goals
directories and files, and simple valid input writes.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 tools/testing/selftests/damon/sysfs.sh | 27 ++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
index 56f0230a8b92..e9a976d296e2 100755
--- a/tools/testing/selftests/damon/sysfs.sh
+++ b/tools/testing/selftests/damon/sysfs.sh
@@ -150,6 +150,32 @@ test_weights()
 	ensure_file "$weights_dir/age_permil" "exist" "600"
 }
 
+test_goal()
+{
+	goal_dir=$1
+	ensure_dir "$goal_dir" "exist"
+	ensure_file "$goal_dir/target_value" "exist" "600"
+	ensure_file "$goal_dir/current_value" "exist" "600"
+}
+
+test_goals()
+{
+	goals_dir=$1
+	ensure_dir "$goals_dir" "exist"
+	ensure_file "$goals_dir/nr_goals" "exist" "600"
+
+	ensure_write_succ  "$goals_dir/nr_goals" "1" "valid input"
+	test_goal "$goals_dir/0"
+
+	ensure_write_succ  "$goals_dir/nr_goals" "2" "valid input"
+	test_goal "$goals_dir/0"
+	test_goal "$goals_dir/1"
+
+	ensure_write_succ  "$goals_dir/nr_goals" "0" "valid input"
+	ensure_dir "$goals_dir/0" "not_exist"
+	ensure_dir "$goals_dir/1" "not_exist"
+}
+
 test_quotas()
 {
 	quotas_dir=$1
@@ -158,6 +184,7 @@ test_quotas()
 	ensure_file "$quotas_dir/bytes" "exist" 600
 	ensure_file "$quotas_dir/reset_interval_ms" "exist" 600
 	test_weights "$quotas_dir/weights"
+	test_goals "$quotas_dir/goals"
 }
 
 test_access_pattern()
-- 
2.34.1

[RFC PATCH 6/8] selftests/damon: test quota goals directory

[SeongJae Park]

Add DAMON selftests for testing creation/existence of quota goals
directories and files, and simple valid input writes.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 tools/testing/selftests/damon/sysfs.sh | 27 ++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tools/testing/selftests/damon/sysfs.sh b/tools/testing/selftests/damon/sysfs.sh
index 56f0230a8b92..e9a976d296e2 100755
--- a/tools/testing/selftests/damon/sysfs.sh
+++ b/tools/testing/selftests/damon/sysfs.sh
@@ -150,6 +150,32 @@ test_weights()
 	ensure_file "$weights_dir/age_permil" "exist" "600"
 }
 
+test_goal()
+{
+	goal_dir=$1
+	ensure_dir "$goal_dir" "exist"
+	ensure_file "$goal_dir/target_value" "exist" "600"
+	ensure_file "$goal_dir/current_value" "exist" "600"
+}
+
+test_goals()
+{
+	goals_dir=$1
+	ensure_dir "$goals_dir" "exist"
+	ensure_file "$goals_dir/nr_goals" "exist" "600"
+
+	ensure_write_succ  "$goals_dir/nr_goals" "1" "valid input"
+	test_goal "$goals_dir/0"
+
+	ensure_write_succ  "$goals_dir/nr_goals" "2" "valid input"
+	test_goal "$goals_dir/0"
+	test_goal "$goals_dir/1"
+
+	ensure_write_succ  "$goals_dir/nr_goals" "0" "valid input"
+	ensure_dir "$goals_dir/0" "not_exist"
+	ensure_dir "$goals_dir/1" "not_exist"
+}
+
 test_quotas()
 {
 	quotas_dir=$1
@@ -158,6 +184,7 @@ test_quotas()
 	ensure_file "$quotas_dir/bytes" "exist" 600
 	ensure_file "$quotas_dir/reset_interval_ms" "exist" 600
 	test_weights "$quotas_dir/weights"
+	test_goals "$quotas_dir/goals"
 }
 
 test_access_pattern()
-- 
2.34.1

[RFC PATCH 7/8] Docs/mm/damon/design: Document DAMOS quota auto tuning

[SeongJae Park]

Document the DAMOS quota auto tuning feature on the design document.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/mm/damon/design.rst | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst
index 1f7e0586b5fa..3e1b34f55bb8 100644
--- a/Documentation/mm/damon/design.rst
+++ b/Documentation/mm/damon/design.rst
@@ -346,6 +346,17 @@ the weight will be respected are up to the underlying prioritization mechanism
 implementation.
 
 
+.. _damon_design_damos_quotas_auto_tuning:
+
+Aim-oriented Feedback-driven Quotas Auto-tuning
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Automatic feedback-driven quota tuning.  Instead of setting the absolute quota
+value, users can provide feedback about how well DAMOS is achieving their goal.
+If the feedback says DAMOS is still not achieving the goal, DAMOS increases the
+quota.  If DAMOS is over-achieving the goal, DAMOS decreases the quota.
+
+
 .. _damon_design_damos_watermarks:
 
 Watermarks
-- 
2.34.1

[RFC PATCH 7/8] Docs/mm/damon/design: Document DAMOS quota auto tuning

[SeongJae Park]

Document the DAMOS quota auto tuning feature on the design document.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/mm/damon/design.rst | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst
index 1f7e0586b5fa..3e1b34f55bb8 100644
--- a/Documentation/mm/damon/design.rst
+++ b/Documentation/mm/damon/design.rst
@@ -346,6 +346,17 @@ the weight will be respected are up to the underlying prioritization mechanism
 implementation.
 
 
+.. _damon_design_damos_quotas_auto_tuning:
+
+Aim-oriented Feedback-driven Quotas Auto-tuning
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Automatic feedback-driven quota tuning.  Instead of setting the absolute quota
+value, users can provide feedback about how well DAMOS is achieving their goal.
+If the feedback says DAMOS is still not achieving the goal, DAMOS increases the
+quota.  If DAMOS is over-achieving the goal, DAMOS decreases the quota.
+
+
 .. _damon_design_damos_watermarks:
 
 Watermarks
-- 
2.34.1

[RFC PATCH 8/8] Docs/admin-guide/mm/damon/usage: update for quota goals

[SeongJae Park]

Update DAMON sysfs usage for newly added DAMOS quota goals interface.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/usage.rst | 25 +++++++++++++++-----
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index da94feb97ed1..3a2d308ca1e1 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -83,6 +83,8 @@ comma (","). ::
     │ │ │ │ │ │ │ │ age/min,max
     │ │ │ │ │ │ │ quotas/ms,bytes,reset_interval_ms
     │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil
+    │ │ │ │ │ │ │ │ goals/nr_goals
+    │ │ │ │ │ │ │ │ │ 0/target_value,current_value
     │ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low
     │ │ │ │ │ │ │ filters/nr_filters
     │ │ │ │ │ │ │ │ 0/type,matching,memcg_id
@@ -123,9 +125,12 @@ Reading ``state`` returns ``on`` if the kdamond is currently running, or
 ``off`` if it is not running.  Writing ``on`` or ``off`` makes the kdamond be
 in the state.  Writing ``commit`` to the ``state`` file makes kdamond reads the
 user inputs in the sysfs files except ``state`` file again.  Writing
-``update_schemes_stats`` to ``state`` file updates the contents of stats files
-for each DAMON-based operation scheme of the kdamond.  For details of the
-stats, please refer to :ref:`stats section <sysfs_schemes_stats>`.
+``commit_schemes_quota_goals`` to the ``state`` file makes kdamond reads the
+DAMON-based operation schemes' :ref:`quota goals <sysfs_schemes_quota_goals>`
+of the kdamond.  Writing ``update_schemes_stats`` to ``state`` file updates the
+contents of stats files for each DAMON-based operation scheme of the kdamond.
+For details of the stats, please refer to :ref:`stats section
+<sysfs_schemes_stats>`.
 
 Writing ``update_schemes_tried_regions`` to ``state`` file updates the
 DAMON-based operation scheme action tried regions directory for each
@@ -319,8 +324,7 @@ The directory for the :ref:`quotas <damon_design_damos_quotas>` of the given
 DAMON-based operation scheme.
 
 Under ``quotas`` directory, three files (``ms``, ``bytes``,
-``reset_interval_ms``) and one directory (``weights``) having three files
-(``sz_permil``, ``nr_accesses_permil``, and ``age_permil``) in it exist.
+``reset_interval_ms``) and two directores (``weights`` and ``goals``) exist.
 
 You can set the ``time quota`` in milliseconds, ``size quota`` in bytes, and
 ``reset interval`` in milliseconds by writing the values to the three files,
@@ -330,11 +334,20 @@ apply the action to only up to ``bytes`` bytes of memory regions within the
 ``reset_interval_ms``.  Setting both ``ms`` and ``bytes`` zero disables the
 quota limits.
 
-You can also set the :ref:`prioritization weights
+Under ``weights`` directory, three files (``sz_permil``,
+``nr_accesses_permil``, and ``age_permil``) exist.
+You can set the :ref:`prioritization weights
 <damon_design_damos_quotas_prioritization>` for size, access frequency, and age
 in per-thousand unit by writing the values to the three files under the
 ``weights`` directory.
 
+.. sysfs_schemes_quota_goals
+
+schemes/<N>/quotas/goals/
+-------------------------
+
+The directory for the DAMOS goals.
+
 schemes/<N>/watermarks/
 -----------------------
 
-- 
2.34.1

[RFC PATCH 8/8] Docs/admin-guide/mm/damon/usage: update for quota goals

[SeongJae Park]

Update DAMON sysfs usage for newly added DAMOS quota goals interface.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/usage.rst | 25 +++++++++++++++-----
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index da94feb97ed1..3a2d308ca1e1 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -83,6 +83,8 @@ comma (","). ::
     │ │ │ │ │ │ │ │ age/min,max
     │ │ │ │ │ │ │ quotas/ms,bytes,reset_interval_ms
     │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil
+    │ │ │ │ │ │ │ │ goals/nr_goals
+    │ │ │ │ │ │ │ │ │ 0/target_value,current_value
     │ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low
     │ │ │ │ │ │ │ filters/nr_filters
     │ │ │ │ │ │ │ │ 0/type,matching,memcg_id
@@ -123,9 +125,12 @@ Reading ``state`` returns ``on`` if the kdamond is currently running, or
 ``off`` if it is not running.  Writing ``on`` or ``off`` makes the kdamond be
 in the state.  Writing ``commit`` to the ``state`` file makes kdamond reads the
 user inputs in the sysfs files except ``state`` file again.  Writing
-``update_schemes_stats`` to ``state`` file updates the contents of stats files
-for each DAMON-based operation scheme of the kdamond.  For details of the
-stats, please refer to :ref:`stats section <sysfs_schemes_stats>`.
+``commit_schemes_quota_goals`` to the ``state`` file makes kdamond reads the
+DAMON-based operation schemes' :ref:`quota goals <sysfs_schemes_quota_goals>`
+of the kdamond.  Writing ``update_schemes_stats`` to ``state`` file updates the
+contents of stats files for each DAMON-based operation scheme of the kdamond.
+For details of the stats, please refer to :ref:`stats section
+<sysfs_schemes_stats>`.
 
 Writing ``update_schemes_tried_regions`` to ``state`` file updates the
 DAMON-based operation scheme action tried regions directory for each
@@ -319,8 +324,7 @@ The directory for the :ref:`quotas <damon_design_damos_quotas>` of the given
 DAMON-based operation scheme.
 
 Under ``quotas`` directory, three files (``ms``, ``bytes``,
-``reset_interval_ms``) and one directory (``weights``) having three files
-(``sz_permil``, ``nr_accesses_permil``, and ``age_permil``) in it exist.
+``reset_interval_ms``) and two directores (``weights`` and ``goals``) exist.
 
 You can set the ``time quota`` in milliseconds, ``size quota`` in bytes, and
 ``reset interval`` in milliseconds by writing the values to the three files,
@@ -330,11 +334,20 @@ apply the action to only up to ``bytes`` bytes of memory regions within the
 ``reset_interval_ms``.  Setting both ``ms`` and ``bytes`` zero disables the
 quota limits.
 
-You can also set the :ref:`prioritization weights
+Under ``weights`` directory, three files (``sz_permil``,
+``nr_accesses_permil``, and ``age_permil``) exist.
+You can set the :ref:`prioritization weights
 <damon_design_damos_quotas_prioritization>` for size, access frequency, and age
 in per-thousand unit by writing the values to the three files under the
 ``weights`` directory.
 
+.. sysfs_schemes_quota_goals
+
+schemes/<N>/quotas/goals/
+-------------------------
+
+The directory for the DAMOS goals.
+
 schemes/<N>/watermarks/
 -----------------------
 
-- 
2.34.1