[RFC PATCH 00/18] efficiently expose damos action tried regions information

[RFC PATCH 00/18] efficiently expose damos action tried regions information

[SeongJae Park]

DAMON users can retrieve the monitoring results via 'after_aggregation'
callbacks if the user is using the kernel API, or 'damon_aggregated'
tracepoint if the user is in the user space.  Those are useful if full
monitoring results are necessary.  However, if the user has interest in
only some regions having specific access pattern, the interfaces could
be inefficient.  For example, some DAMOS users might want to know
exactly what regions were identified as fulfilling the access pattern of
the scheme, for a debugging or a tuning.

This patchset implements DAMON kernel API callbacks and sysfs directory
for efficient exposure of the information.  The new callback will be
called for each region before specific DAMOS action is gonna tried to be
applied.  The sysfs directory will be called 'tried_regions' and placed
under each scheme sysfs directory.  User can write a special keyworkd,
'update_schemes_regions' to the 'state' file of a kdamond sysfs
directory.  Then, DAMON sysfs interface will fill the directory with the
information of regions that corresponding scheme action was tried to be
applied for one aggregation interval.

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

First five patches (1-5) clean up and refactor code that following patch
will touch, and the following one (patch 6) implements the DAMON
callback for DAMON kernel API users.

Following six patches (7-12) clean up and refactor the sysfs interface
before the new sysfs directory introduction.  Following two patches (13
and 14) implement the sysfs directories, and successing two patches (15
and 16) implement the special keyword for 'state' to fill and clean up
the directories.

Finally, two more patches (17 and 18) for the documentation of the usage
and ABI follow.

Assembled Tree
--------------

This patchset is based on the latest mm-unstable tree[1].  Assembled
tree is also available at the damon/next tree[2].

[1] https://git.kernel.org/akpm/mm/h/mm-unstable
[2] https://git.kernel.org/sj/h/damon/next

SeongJae Park (18):
  mm/damon/modules: deduplicate init steps for DAMON context setup
  mm/damon/core: split out DAMOS-charged region skip logic into a new
    function
  mm/damon/core: split damos application logic into a new function
  mm/damon/core: split out scheme stat update logic into a new function
  mm/damon/core: split out scheme quota adjustment logic into a new
    function
  mm/damon/core: add a DAMON callback for scheme target regions check
  mm/damon/sysfs: Use damon_addr_range for regions' start and end values
  mm/damon/sysfs: remove parameters of damon_sysfs_region_alloc()
  mm/damon/sysfs: move sysfs_lock to common module
  mm/damon/sysfs: move unsigned long range directory to common module
  mm/damon/sysfs: split out kdamond-independent schemes stats update
    logic into a new function
  mm/damon/sysfs: move schemes directory implementation to separate
    module
  mm/damon/sysfs-schemes: implement schemes/tried_regions directory
  mm/damon/sysfs-schemes: implement scheme region directory
  mm/damon/sysfs: implement DAMOS-tried regions update command
  mm/damon/sysfs-schemes: implement DAMOS tried regions clear command
  Docs/admin-guide/mm/damon/usage: document schemes/<s>/tried_regions
    directory
  Docs/ABI/damon: document 'schemes/<s>/tried_regions' directory

 .../ABI/testing/sysfs-kernel-mm-damon         |   32 +
 Documentation/admin-guide/mm/damon/usage.rst  |   44 +-
 include/linux/damon.h                         |    5 +
 mm/damon/Makefile                             |    6 +-
 mm/damon/core.c                               |  259 ++--
 mm/damon/lru_sort.c                           |   17 +-
 mm/damon/modules-common.c                     |   42 +
 mm/damon/modules-common.h                     |    3 +
 mm/damon/reclaim.c                            |   17 +-
 mm/damon/sysfs-common.c                       |  107 ++
 mm/damon/sysfs-common.h                       |   56 +
 mm/damon/sysfs-schemes.c                      | 1281 +++++++++++++++++
 mm/damon/sysfs.c                              | 1224 ++--------------
 13 files changed, 1813 insertions(+), 1280 deletions(-)
 create mode 100644 mm/damon/modules-common.c
 create mode 100644 mm/damon/sysfs-common.c
 create mode 100644 mm/damon/sysfs-common.h
 create mode 100644 mm/damon/sysfs-schemes.c

-- 
2.25.1

[RFC PATCH 01/18] mm/damon/modules: deduplicate init steps for DAMON context setup

[SeongJae Park]

DAMON_RECLAIM and DAMON_LRU_SORT has duplicated code for DAMON context
and target initializations.  Deduplicate the part by implementing a
function for the initialization in 'modules-common.c' and using it.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/Makefile         |  4 ++--
 mm/damon/lru_sort.c       | 17 +++-------------
 mm/damon/modules-common.c | 42 +++++++++++++++++++++++++++++++++++++++
 mm/damon/modules-common.h |  3 +++
 mm/damon/reclaim.c        | 17 +++-------------
 5 files changed, 53 insertions(+), 30 deletions(-)
 create mode 100644 mm/damon/modules-common.c

diff --git a/mm/damon/Makefile b/mm/damon/Makefile
index 3e6b8ad73858..a076ccd55d44 100644
--- a/mm/damon/Makefile
+++ b/mm/damon/Makefile
@@ -5,5 +5,5 @@ obj-$(CONFIG_DAMON_VADDR)	+= ops-common.o vaddr.o
 obj-$(CONFIG_DAMON_PADDR)	+= ops-common.o paddr.o
 obj-$(CONFIG_DAMON_SYSFS)	+= sysfs.o
 obj-$(CONFIG_DAMON_DBGFS)	+= dbgfs.o
-obj-$(CONFIG_DAMON_RECLAIM)	+= reclaim.o
-obj-$(CONFIG_DAMON_LRU_SORT)	+= lru_sort.o
+obj-$(CONFIG_DAMON_RECLAIM)	+= modules-common.o reclaim.o
+obj-$(CONFIG_DAMON_LRU_SORT)	+= modules-common.o lru_sort.o
diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c
index efbc2bda8b9c..a1896c5acfe9 100644
--- a/mm/damon/lru_sort.c
+++ b/mm/damon/lru_sort.c
@@ -314,25 +314,14 @@ static int damon_lru_sort_after_wmarks_check(struct damon_ctx *c)
 
 static int __init damon_lru_sort_init(void)
 {
-	ctx = damon_new_ctx();
-	if (!ctx)
-		return -ENOMEM;
+	int err = damon_modules_new_paddr_ctx_target(&ctx, &target);
 
-	if (damon_select_ops(ctx, DAMON_OPS_PADDR)) {
-		damon_destroy_ctx(ctx);
-		return -EINVAL;
-	}
+	if (err)
+		return err;
 
 	ctx->callback.after_wmarks_check = damon_lru_sort_after_wmarks_check;
 	ctx->callback.after_aggregation = damon_lru_sort_after_aggregation;
 
-	target = damon_new_target();
-	if (!target) {
-		damon_destroy_ctx(ctx);
-		return -ENOMEM;
-	}
-	damon_add_target(ctx, target);
-
 	schedule_delayed_work(&damon_lru_sort_timer, 0);
 
 	damon_lru_sort_initialized = true;
diff --git a/mm/damon/modules-common.c b/mm/damon/modules-common.c
new file mode 100644
index 000000000000..b2381a8466ec
--- /dev/null
+++ b/mm/damon/modules-common.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Common Primitives for DAMON Modules
+ *
+ * Author: SeongJae Park <sjpark@amazon.de>
+ */
+
+#include <linux/damon.h>
+
+#include "modules-common.h"
+
+/*
+ * Allocate, set, and return a DAMON context for the physical address space.
+ * @ctxp:	Pointer to save the point to the newly created context
+ * @targetp:	Pointer to save the point to the newly created target
+ */
+int damon_modules_new_paddr_ctx_target(struct damon_ctx **ctxp,
+		struct damon_target **targetp)
+{
+	struct damon_ctx *ctx;
+	struct damon_target *target;
+
+	ctx = damon_new_ctx();
+	if (!ctx)
+		return -ENOMEM;
+
+	if (damon_select_ops(ctx, DAMON_OPS_PADDR)) {
+		damon_destroy_ctx(ctx);
+		return -EINVAL;
+	}
+
+	target = damon_new_target();
+	if (!target) {
+		damon_destroy_ctx(ctx);
+		return -ENOMEM;
+	}
+	damon_add_target(ctx, target);
+
+	*ctxp = ctx;
+	*targetp = target;
+	return 0;
+}
diff --git a/mm/damon/modules-common.h b/mm/damon/modules-common.h
index 5a4921851d32..f49cdb417005 100644
--- a/mm/damon/modules-common.h
+++ b/mm/damon/modules-common.h
@@ -44,3 +44,6 @@
 			0400);						\
 	module_param_named(nr_##qt_exceed_name, stat.qt_exceeds, ulong,	\
 			0400);
+
+int damon_modules_new_paddr_ctx_target(struct damon_ctx **ctxp,
+		struct damon_target **targetp);
diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
index 162c9b1ca00f..3173f373435c 100644
--- a/mm/damon/reclaim.c
+++ b/mm/damon/reclaim.c
@@ -256,25 +256,14 @@ static int damon_reclaim_after_wmarks_check(struct damon_ctx *c)
 
 static int __init damon_reclaim_init(void)
 {
-	ctx = damon_new_ctx();
-	if (!ctx)
-		return -ENOMEM;
+	int err = damon_modules_new_paddr_ctx_target(&ctx, &target);
 
-	if (damon_select_ops(ctx, DAMON_OPS_PADDR)) {
-		damon_destroy_ctx(ctx);
-		return -EINVAL;
-	}
+	if (err)
+		return err;
 
 	ctx->callback.after_wmarks_check = damon_reclaim_after_wmarks_check;
 	ctx->callback.after_aggregation = damon_reclaim_after_aggregation;
 
-	target = damon_new_target();
-	if (!target) {
-		damon_destroy_ctx(ctx);
-		return -ENOMEM;
-	}
-	damon_add_target(ctx, target);
-
 	schedule_delayed_work(&damon_reclaim_timer, 0);
 
 	damon_reclaim_initialized = true;
-- 
2.25.1

[RFC PATCH 02/18] mm/damon/core: split out DAMOS-charged region skip logic into a new function

[SeongJae Park]

The DAMOS action applying function, 'damon_do_apply_schemes()', is quite
long and not easy to read.  Split out the already quota-charged region
skip code into a new function with some comments for better readability.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core.c | 89 ++++++++++++++++++++++++++++++++-----------------
 1 file changed, 58 insertions(+), 31 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 36d098d06c55..eec258b3e57b 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -694,6 +694,60 @@ static bool damos_valid_target(struct damon_ctx *c, struct damon_target *t,
 	return c->ops.get_scheme_score(c, t, r, s) >= s->quota.min_score;
 }
 
+/*
+ * damos_skip_charged_region() - Check if the given region or starting part of
+ * it is already charged for the DAMOS quota.
+ * @t:	The target of the region.
+ * @rp:	The pointer to the region.
+ * @s:	The scheme to be applied.
+ *
+ * If the scheme has applied to only a part of the memory regions fulfilling
+ * the access pattern due to the charge limit, we start from the memory region
+ * of the access pattern after already charged one.  For this, this function
+ * checks if current region should be skipped or not.  If only the starting
+ * part of the region is previously charged, this function splits the region
+ * into two, so that the second one can start DAMOS, and saves the second
+ * region in *rp.
+ */
+static bool damos_skip_charged_region(struct damon_target *t,
+		struct damon_region **rp, struct damos *s)
+{
+	struct damon_region *r = *rp;
+	struct damos_quota *quota = &s->quota;
+	unsigned long sz_to_skip;
+
+	/* Skip previously charged regions */
+	if (quota->charge_target_from) {
+		if (t != quota->charge_target_from)
+			return true;
+		if (r == damon_last_region(t)) {
+			quota->charge_target_from = NULL;
+			quota->charge_addr_from = 0;
+			return true;
+		}
+		if (quota->charge_addr_from &&
+				r->ar.end <= quota->charge_addr_from)
+			return true;
+
+		if (quota->charge_addr_from && r->ar.start <
+				quota->charge_addr_from) {
+			sz_to_skip = ALIGN_DOWN(quota->charge_addr_from -
+					r->ar.start, DAMON_MIN_REGION);
+			if (!sz_to_skip) {
+				if (damon_sz_region(r) <= DAMON_MIN_REGION)
+					return true;
+				sz_to_skip = DAMON_MIN_REGION;
+			}
+			damon_split_region_at(t, r, sz_to_skip);
+			r = damon_next_region(r);
+			*rp = r;
+		}
+		quota->charge_target_from = NULL;
+		quota->charge_addr_from = 0;
+	}
+	return false;
+}
+
 static void damon_do_apply_schemes(struct damon_ctx *c,
 				   struct damon_target *t,
 				   struct damon_region *r)
@@ -702,7 +756,7 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 
 	damon_for_each_scheme(s, c) {
 		struct damos_quota *quota = &s->quota;
-		unsigned long sz = damon_sz_region(r);
+		unsigned long sz;
 		struct timespec64 begin, end;
 		unsigned long sz_applied = 0;
 
@@ -713,41 +767,14 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 		if (quota->esz && quota->charged_sz >= quota->esz)
 			continue;
 
-		/* Skip previously charged regions */
-		if (quota->charge_target_from) {
-			if (t != quota->charge_target_from)
-				continue;
-			if (r == damon_last_region(t)) {
-				quota->charge_target_from = NULL;
-				quota->charge_addr_from = 0;
-				continue;
-			}
-			if (quota->charge_addr_from &&
-					r->ar.end <= quota->charge_addr_from)
-				continue;
-
-			if (quota->charge_addr_from && r->ar.start <
-					quota->charge_addr_from) {
-				sz = ALIGN_DOWN(quota->charge_addr_from -
-						r->ar.start, DAMON_MIN_REGION);
-				if (!sz) {
-					if (damon_sz_region(r) <=
-					    DAMON_MIN_REGION)
-						continue;
-					sz = DAMON_MIN_REGION;
-				}
-				damon_split_region_at(t, r, sz);
-				r = damon_next_region(r);
-				sz = damon_sz_region(r);
-			}
-			quota->charge_target_from = NULL;
-			quota->charge_addr_from = 0;
-		}
+		if (damos_skip_charged_region(t, &r, s))
+			continue;
 
 		if (!damos_valid_target(c, t, r, s))
 			continue;
 
 		/* Apply the scheme */
+		sz = damon_sz_region(r);
 		if (c->ops.apply_scheme) {
 			if (quota->esz &&
 					quota->charged_sz + sz > quota->esz) {
-- 
2.25.1

[RFC PATCH 03/18] mm/damon/core: split damos application logic into a new function

[SeongJae Park]

The DAMOS action applying function, 'damon_do_apply_schemes()', is still
long and not easy to read.  Split out the code for applying a single
action to a single region into a new function for better readability.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core.c | 72 ++++++++++++++++++++++++++-----------------------
 1 file changed, 39 insertions(+), 33 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index eec258b3e57b..e777a751295f 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -748,6 +748,44 @@ static bool damos_skip_charged_region(struct damon_target *t,
 	return false;
 }
 
+static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
+		struct damon_region *r, struct damos *s)
+{
+	struct damos_quota *quota = &s->quota;
+	unsigned long sz = damon_sz_region(r);
+	struct timespec64 begin, end;
+	unsigned long sz_applied = 0;
+
+	if (c->ops.apply_scheme) {
+		if (quota->esz && quota->charged_sz + sz > quota->esz) {
+			sz = ALIGN_DOWN(quota->esz - quota->charged_sz,
+					DAMON_MIN_REGION);
+			if (!sz)
+				goto update_stat;
+			damon_split_region_at(t, r, sz);
+		}
+		ktime_get_coarse_ts64(&begin);
+		sz_applied = c->ops.apply_scheme(c, t, r, s);
+		ktime_get_coarse_ts64(&end);
+		quota->total_charged_ns += timespec64_to_ns(&end) -
+			timespec64_to_ns(&begin);
+		quota->charged_sz += sz;
+		if (quota->esz && quota->charged_sz >= quota->esz) {
+			quota->charge_target_from = t;
+			quota->charge_addr_from = r->ar.end + 1;
+		}
+	}
+	if (s->action != DAMOS_STAT)
+		r->age = 0;
+
+update_stat:
+	s->stat.nr_tried++;
+	s->stat.sz_tried += sz;
+	if (sz_applied)
+		s->stat.nr_applied++;
+	s->stat.sz_applied += sz_applied;
+}
+
 static void damon_do_apply_schemes(struct damon_ctx *c,
 				   struct damon_target *t,
 				   struct damon_region *r)
@@ -756,9 +794,6 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 
 	damon_for_each_scheme(s, c) {
 		struct damos_quota *quota = &s->quota;
-		unsigned long sz;
-		struct timespec64 begin, end;
-		unsigned long sz_applied = 0;
 
 		if (!s->wmarks.activated)
 			continue;
@@ -774,36 +809,7 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 			continue;
 
 		/* Apply the scheme */
-		sz = damon_sz_region(r);
-		if (c->ops.apply_scheme) {
-			if (quota->esz &&
-					quota->charged_sz + sz > quota->esz) {
-				sz = ALIGN_DOWN(quota->esz - quota->charged_sz,
-						DAMON_MIN_REGION);
-				if (!sz)
-					goto update_stat;
-				damon_split_region_at(t, r, sz);
-			}
-			ktime_get_coarse_ts64(&begin);
-			sz_applied = c->ops.apply_scheme(c, t, r, s);
-			ktime_get_coarse_ts64(&end);
-			quota->total_charged_ns += timespec64_to_ns(&end) -
-				timespec64_to_ns(&begin);
-			quota->charged_sz += sz;
-			if (quota->esz && quota->charged_sz >= quota->esz) {
-				quota->charge_target_from = t;
-				quota->charge_addr_from = r->ar.end + 1;
-			}
-		}
-		if (s->action != DAMOS_STAT)
-			r->age = 0;
-
-update_stat:
-		s->stat.nr_tried++;
-		s->stat.sz_tried += sz;
-		if (sz_applied)
-			s->stat.nr_applied++;
-		s->stat.sz_applied += sz_applied;
+		damos_apply_scheme(c, t, r, s);
 	}
 }
 
-- 
2.25.1

[RFC PATCH 04/18] mm/damon/core: split out scheme stat update logic into a new function

[SeongJae Park]

The function for applying a given DAMON scheme action to a given DAMON
region, 'damos_apply_scheme()' is not quite short.  Make it better to
read by splitting out the stat update logic into a new function.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index e777a751295f..7fa88dda711d 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -748,6 +748,16 @@ static bool damos_skip_charged_region(struct damon_target *t,
 	return false;
 }
 
+static void damos_update_stat(struct damos *s,
+		unsigned long sz_tried, unsigned long sz_applied)
+{
+	s->stat.nr_tried++;
+	s->stat.sz_tried += sz_tried;
+	if (sz_applied)
+		s->stat.nr_applied++;
+	s->stat.sz_applied += sz_applied;
+}
+
 static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 		struct damon_region *r, struct damos *s)
 {
@@ -779,11 +789,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 		r->age = 0;
 
 update_stat:
-	s->stat.nr_tried++;
-	s->stat.sz_tried += sz;
-	if (sz_applied)
-		s->stat.nr_applied++;
-	s->stat.sz_applied += sz_applied;
+	damos_update_stat(s, sz, sz_applied);
 }
 
 static void damon_do_apply_schemes(struct damon_ctx *c,
@@ -808,7 +814,6 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 		if (!damos_valid_target(c, t, r, s))
 			continue;
 
-		/* Apply the scheme */
 		damos_apply_scheme(c, t, r, s);
 	}
 }
-- 
2.25.1

[RFC PATCH 05/18] mm/damon/core: split out scheme quota adjustment logic into a new function

[SeongJae Park]

DAMOS quota adjustment logic in 'kdamond_apply_schemes()', has some
amount of code, and the logic is not so straightforward.  Split it out
to a new function for better readability.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/core.c | 91 ++++++++++++++++++++++++++-----------------------
 1 file changed, 48 insertions(+), 43 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 7fa88dda711d..9ee9f752f6fc 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -841,59 +841,64 @@ static void damos_set_effective_quota(struct damos_quota *quota)
 	quota->esz = esz;
 }
 
-static void kdamond_apply_schemes(struct damon_ctx *c)
+static void damos_adjust_quota(struct damon_ctx *c, struct damos *s)
 {
+	struct damos_quota *quota = &s->quota;
 	struct damon_target *t;
-	struct damon_region *r, *next_r;
-	struct damos *s;
+	struct damon_region *r;
+	unsigned long cumulated_sz;
+	unsigned int score, max_score = 0;
 
-	damon_for_each_scheme(s, c) {
-		struct damos_quota *quota = &s->quota;
-		unsigned long cumulated_sz;
-		unsigned int score, max_score = 0;
+	if (!quota->ms && !quota->sz)
+		return;
 
-		if (!s->wmarks.activated)
-			continue;
+	/* New charge window starts */
+	if (time_after_eq(jiffies, quota->charged_from +
+				msecs_to_jiffies(quota->reset_interval))) {
+		if (quota->esz && quota->charged_sz >= quota->esz)
+			s->stat.qt_exceeds++;
+		quota->total_charged_sz += quota->charged_sz;
+		quota->charged_from = jiffies;
+		quota->charged_sz = 0;
+		damos_set_effective_quota(quota);
+	}
 
-		if (!quota->ms && !quota->sz)
-			continue;
+	if (!c->ops.get_scheme_score)
+		return;
 
-		/* New charge window starts */
-		if (time_after_eq(jiffies, quota->charged_from +
-					msecs_to_jiffies(
-						quota->reset_interval))) {
-			if (quota->esz && quota->charged_sz >= quota->esz)
-				s->stat.qt_exceeds++;
-			quota->total_charged_sz += quota->charged_sz;
-			quota->charged_from = jiffies;
-			quota->charged_sz = 0;
-			damos_set_effective_quota(quota);
+	/* Fill up the score histogram */
+	memset(quota->histogram, 0, sizeof(quota->histogram));
+	damon_for_each_target(t, c) {
+		damon_for_each_region(r, t) {
+			if (!__damos_valid_target(r, s))
+				continue;
+			score = c->ops.get_scheme_score(c, t, r, s);
+			quota->histogram[score] += damon_sz_region(r);
+			if (score > max_score)
+				max_score = score;
 		}
+	}
 
-		if (!c->ops.get_scheme_score)
-			continue;
+	/* Set the min score limit */
+	for (cumulated_sz = 0, score = max_score; ; score--) {
+		cumulated_sz += quota->histogram[score];
+		if (cumulated_sz >= quota->esz || !score)
+			break;
+	}
+	quota->min_score = score;
+}
 
-		/* Fill up the score histogram */
-		memset(quota->histogram, 0, sizeof(quota->histogram));
-		damon_for_each_target(t, c) {
-			damon_for_each_region(r, t) {
-				if (!__damos_valid_target(r, s))
-					continue;
-				score = c->ops.get_scheme_score(
-						c, t, r, s);
-				quota->histogram[score] += damon_sz_region(r);
-				if (score > max_score)
-					max_score = score;
-			}
-		}
+static void kdamond_apply_schemes(struct damon_ctx *c)
+{
+	struct damon_target *t;
+	struct damon_region *r, *next_r;
+	struct damos *s;
 
-		/* Set the min score limit */
-		for (cumulated_sz = 0, score = max_score; ; score--) {
-			cumulated_sz += quota->histogram[score];
-			if (cumulated_sz >= quota->esz || !score)
-				break;
-		}
-		quota->min_score = score;
+	damon_for_each_scheme(s, c) {
+		if (!s->wmarks.activated)
+			continue;
+
+		damos_adjust_quota(c, s);
 	}
 
 	damon_for_each_target(t, c) {
-- 
2.25.1

[RFC PATCH 06/18] mm/damon/core: add a DAMON callback for scheme target regions check

[SeongJae Park]

For deep level investigation of DAMON, knowing exactly to what regions
each DAMON-based operation scheme is applied is helpful.  It can also be
very helpful for efficient monitoring results passing when the user has
interest in regions of specific access patterns.  Add a new DAMON
callback that will be called before each scheme is applied to each
region, to provide the functionality to the kernel API users.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 include/linux/damon.h | 5 +++++
 mm/damon/core.c       | 6 +++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 620ada094c3b..35630634d790 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -357,6 +357,7 @@ struct damon_operations {
  * @after_wmarks_check:	Called after each schemes' watermarks check.
  * @after_sampling:	Called after each sampling.
  * @after_aggregation:	Called after each aggregation.
+ * @before_damos_apply:	Called before applying DAMOS action.
  * @before_terminate:	Called before terminating the monitoring.
  * @private:		User private data.
  *
@@ -385,6 +386,10 @@ struct damon_callback {
 	int (*after_wmarks_check)(struct damon_ctx *context);
 	int (*after_sampling)(struct damon_ctx *context);
 	int (*after_aggregation)(struct damon_ctx *context);
+	int (*before_damos_apply)(struct damon_ctx *context,
+			struct damon_target *target,
+			struct damon_region *region,
+			struct damos *scheme);
 	void (*before_terminate)(struct damon_ctx *context);
 };
 
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 9ee9f752f6fc..f196feed78c7 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -765,6 +765,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 	unsigned long sz = damon_sz_region(r);
 	struct timespec64 begin, end;
 	unsigned long sz_applied = 0;
+	int err = 0;
 
 	if (c->ops.apply_scheme) {
 		if (quota->esz && quota->charged_sz + sz > quota->esz) {
@@ -775,7 +776,10 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 			damon_split_region_at(t, r, sz);
 		}
 		ktime_get_coarse_ts64(&begin);
-		sz_applied = c->ops.apply_scheme(c, t, r, s);
+		if (c->callback.before_damos_apply)
+			err = c->callback.before_damos_apply(c, t, r, s);
+		if (!err)
+			sz_applied = c->ops.apply_scheme(c, t, r, s);
 		ktime_get_coarse_ts64(&end);
 		quota->total_charged_ns += timespec64_to_ns(&end) -
 			timespec64_to_ns(&begin);
-- 
2.25.1

[RFC PATCH 07/18] mm/damon/sysfs: Use damon_addr_range for regions' start and end values

[SeongJae Park]

DAMON has a struct for each address range but DAMON sysfs interface is
using the low type (unsigned long) for storing the start and end
addresses of regions.  Use the dedicated struct for better type safety.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 9f1219a67e3f..b9183063bfea 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1062,13 +1062,11 @@ static struct kobj_type damon_sysfs_schemes_ktype = {
 
 struct damon_sysfs_region {
 	struct kobject kobj;
-	unsigned long start;
-	unsigned long end;
+	struct damon_addr_range ar;
 };
 
 static struct damon_sysfs_region *damon_sysfs_region_alloc(
-		unsigned long start,
-		unsigned long end)
+		struct damon_addr_range ar)
 {
 	struct damon_sysfs_region *region = kmalloc(sizeof(*region),
 			GFP_KERNEL);
@@ -1076,8 +1074,7 @@ static struct damon_sysfs_region *damon_sysfs_region_alloc(
 	if (!region)
 		return NULL;
 	region->kobj = (struct kobject){};
-	region->start = start;
-	region->end = end;
+	region->ar = ar;
 	return region;
 }
 
@@ -1087,7 +1084,7 @@ static ssize_t start_show(struct kobject *kobj, struct kobj_attribute *attr,
 	struct damon_sysfs_region *region = container_of(kobj,
 			struct damon_sysfs_region, kobj);
 
-	return sysfs_emit(buf, "%lu\n", region->start);
+	return sysfs_emit(buf, "%lu\n", region->ar.start);
 }
 
 static ssize_t start_store(struct kobject *kobj, struct kobj_attribute *attr,
@@ -1095,7 +1092,7 @@ static ssize_t start_store(struct kobject *kobj, struct kobj_attribute *attr,
 {
 	struct damon_sysfs_region *region = container_of(kobj,
 			struct damon_sysfs_region, kobj);
-	int err = kstrtoul(buf, 0, &region->start);
+	int err = kstrtoul(buf, 0, &region->ar.start);
 
 	return err ? err : count;
 }
@@ -1106,7 +1103,7 @@ static ssize_t end_show(struct kobject *kobj, struct kobj_attribute *attr,
 	struct damon_sysfs_region *region = container_of(kobj,
 			struct damon_sysfs_region, kobj);
 
-	return sysfs_emit(buf, "%lu\n", region->end);
+	return sysfs_emit(buf, "%lu\n", region->ar.end);
 }
 
 static ssize_t end_store(struct kobject *kobj, struct kobj_attribute *attr,
@@ -1114,7 +1111,7 @@ static ssize_t end_store(struct kobject *kobj, struct kobj_attribute *attr,
 {
 	struct damon_sysfs_region *region = container_of(kobj,
 			struct damon_sysfs_region, kobj);
-	int err = kstrtoul(buf, 0, &region->end);
+	int err = kstrtoul(buf, 0, &region->ar.end);
 
 	return err ? err : count;
 }
@@ -1187,7 +1184,7 @@ static int damon_sysfs_regions_add_dirs(struct damon_sysfs_regions *regions,
 	regions->regions_arr = regions_arr;
 
 	for (i = 0; i < nr_regions; i++) {
-		region = damon_sysfs_region_alloc(0, 0);
+		region = damon_sysfs_region_alloc((struct damon_addr_range){});
 		if (!region) {
 			damon_sysfs_regions_rm_dirs(regions);
 			return -ENOMEM;
@@ -2147,11 +2144,11 @@ static int damon_sysfs_set_regions(struct damon_target *t,
 		struct damon_sysfs_region *sys_region =
 			sysfs_regions->regions_arr[i];
 
-		if (sys_region->start > sys_region->end)
+		if (sys_region->ar.start > sys_region->ar.end)
 			goto out;
 
-		ranges[i].start = sys_region->start;
-		ranges[i].end = sys_region->end;
+		ranges[i].start = sys_region->ar.start;
+		ranges[i].end = sys_region->ar.end;
 		if (i == 0)
 			continue;
 		if (ranges[i - 1].end > ranges[i].start)
-- 
2.25.1

[RFC PATCH 08/18] mm/damon/sysfs: remove parameters of damon_sysfs_region_alloc()

[SeongJae Park]

'damon_sysfs_region_alloc()' is always called with zero-filled 'struct
damon_addr_range', because the start and end addresses should set by
users.  Remove unnecessary parameters of the function and simplify the
body by using 'kzalloc()'.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index b9183063bfea..e8bd7367d15b 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1065,17 +1065,9 @@ struct damon_sysfs_region {
 	struct damon_addr_range ar;
 };
 
-static struct damon_sysfs_region *damon_sysfs_region_alloc(
-		struct damon_addr_range ar)
+static struct damon_sysfs_region *damon_sysfs_region_alloc(void)
 {
-	struct damon_sysfs_region *region = kmalloc(sizeof(*region),
-			GFP_KERNEL);
-
-	if (!region)
-		return NULL;
-	region->kobj = (struct kobject){};
-	region->ar = ar;
-	return region;
+	return kzalloc(sizeof(struct damon_sysfs_region), GFP_KERNEL);
 }
 
 static ssize_t start_show(struct kobject *kobj, struct kobj_attribute *attr,
@@ -1184,7 +1176,7 @@ static int damon_sysfs_regions_add_dirs(struct damon_sysfs_regions *regions,
 	regions->regions_arr = regions_arr;
 
 	for (i = 0; i < nr_regions; i++) {
-		region = damon_sysfs_region_alloc((struct damon_addr_range){});
+		region = damon_sysfs_region_alloc();
 		if (!region) {
 			damon_sysfs_regions_rm_dirs(regions);
 			return -ENOMEM;
-- 
2.25.1

[RFC PATCH 09/18] mm/damon/sysfs: move sysfs_lock to common module

[SeongJae Park]

DAMON sysfs interface is implemented in a single file, sysfs.c, which
has about 2,800 lines of code.  As the interface is hierarchical and
some of the code can be reused by different hierarchies, it would make
more sense to split the implementation into common parts and different
parts in multiple files.  As the beginning of the work, create files for
common code and move the global mutex for directories modifications
protection into the files.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/Makefile       |  2 +-
 mm/damon/sysfs-common.c | 11 +++++++++++
 mm/damon/sysfs-common.h | 11 +++++++++++
 mm/damon/sysfs.c        |  4 +---
 4 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 mm/damon/sysfs-common.c
 create mode 100644 mm/damon/sysfs-common.h

diff --git a/mm/damon/Makefile b/mm/damon/Makefile
index a076ccd55d44..50d6b2ab3956 100644
--- a/mm/damon/Makefile
+++ b/mm/damon/Makefile
@@ -3,7 +3,7 @@
 obj-y				:= core.o
 obj-$(CONFIG_DAMON_VADDR)	+= ops-common.o vaddr.o
 obj-$(CONFIG_DAMON_PADDR)	+= ops-common.o paddr.o
-obj-$(CONFIG_DAMON_SYSFS)	+= sysfs.o
+obj-$(CONFIG_DAMON_SYSFS)	+= sysfs-common.o sysfs.o
 obj-$(CONFIG_DAMON_DBGFS)	+= dbgfs.o
 obj-$(CONFIG_DAMON_RECLAIM)	+= modules-common.o reclaim.o
 obj-$(CONFIG_DAMON_LRU_SORT)	+= modules-common.o lru_sort.o
diff --git a/mm/damon/sysfs-common.c b/mm/damon/sysfs-common.c
new file mode 100644
index 000000000000..9dc743868d5b
--- /dev/null
+++ b/mm/damon/sysfs-common.c
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Common Primitives for DAMON Sysfs Interface
+ *
+ * Author: SeongJae Park <sj@kernel.org>
+ */
+
+#include "sysfs-common.h"
+
+DEFINE_MUTEX(damon_sysfs_lock);
+
diff --git a/mm/damon/sysfs-common.h b/mm/damon/sysfs-common.h
new file mode 100644
index 000000000000..745a918b94f5
--- /dev/null
+++ b/mm/damon/sysfs-common.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common Primitives for DAMON Sysfs Interface
+ *
+ * Author: SeongJae Park <sj@kernel.org>
+ */
+
+#include <linux/damon.h>
+#include <linux/kobject.h>
+
+extern struct mutex damon_sysfs_lock;
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index e8bd7367d15b..0f3f06d8dae7 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -5,13 +5,11 @@
  * Copyright (c) 2022 SeongJae Park <sj@kernel.org>
  */
 
-#include <linux/damon.h>
-#include <linux/kobject.h>
 #include <linux/pid.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 
-static DEFINE_MUTEX(damon_sysfs_lock);
+#include "sysfs-common.h"
 
 /*
  * unsigned long range directory
-- 
2.25.1

[RFC PATCH 10/18] mm/damon/sysfs: move unsigned long range directory to common module

[SeongJae Park]

The implementation of unsigned long type range directories can be reused
by multiple DAMON sysfs directories including those for DAMON-based
Operation Schemes and the range of number of monitoring regions.  Move
the code into the files for DAMON sysfs common logics.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-common.c |  96 ++++++++++++++++++++++++++++++++++++++
 mm/damon/sysfs-common.h |  13 ++++++
 mm/damon/sysfs.c        | 100 ----------------------------------------
 3 files changed, 109 insertions(+), 100 deletions(-)

diff --git a/mm/damon/sysfs-common.c b/mm/damon/sysfs-common.c
index 9dc743868d5b..52bebf242f74 100644
--- a/mm/damon/sysfs-common.c
+++ b/mm/damon/sysfs-common.c
@@ -5,7 +5,103 @@
  * Author: SeongJae Park <sj@kernel.org>
  */
 
+#include <linux/slab.h>
+
 #include "sysfs-common.h"
 
 DEFINE_MUTEX(damon_sysfs_lock);
 
+/*
+ * unsigned long range directory
+ */
+
+struct damon_sysfs_ul_range *damon_sysfs_ul_range_alloc(
+		unsigned long min,
+		unsigned long max)
+{
+	struct damon_sysfs_ul_range *range = kmalloc(sizeof(*range),
+			GFP_KERNEL);
+
+	if (!range)
+		return NULL;
+	range->kobj = (struct kobject){};
+	range->min = min;
+	range->max = max;
+
+	return range;
+}
+
+static ssize_t min_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_ul_range *range = container_of(kobj,
+			struct damon_sysfs_ul_range, kobj);
+
+	return sysfs_emit(buf, "%lu\n", range->min);
+}
+
+static ssize_t min_store(struct kobject *kobj, struct kobj_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct damon_sysfs_ul_range *range = container_of(kobj,
+			struct damon_sysfs_ul_range, kobj);
+	unsigned long min;
+	int err;
+
+	err = kstrtoul(buf, 0, &min);
+	if (err)
+		return err;
+
+	range->min = min;
+	return count;
+}
+
+static ssize_t max_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_ul_range *range = container_of(kobj,
+			struct damon_sysfs_ul_range, kobj);
+
+	return sysfs_emit(buf, "%lu\n", range->max);
+}
+
+static ssize_t max_store(struct kobject *kobj, struct kobj_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct damon_sysfs_ul_range *range = container_of(kobj,
+			struct damon_sysfs_ul_range, kobj);
+	unsigned long max;
+	int err;
+
+	err = kstrtoul(buf, 0, &max);
+	if (err)
+		return err;
+
+	range->max = max;
+	return count;
+}
+
+void damon_sysfs_ul_range_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_ul_range, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_ul_range_min_attr =
+		__ATTR_RW_MODE(min, 0600);
+
+static struct kobj_attribute damon_sysfs_ul_range_max_attr =
+		__ATTR_RW_MODE(max, 0600);
+
+static struct attribute *damon_sysfs_ul_range_attrs[] = {
+	&damon_sysfs_ul_range_min_attr.attr,
+	&damon_sysfs_ul_range_max_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_ul_range);
+
+struct kobj_type damon_sysfs_ul_range_ktype = {
+	.release = damon_sysfs_ul_range_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_ul_range_groups,
+};
+
diff --git a/mm/damon/sysfs-common.h b/mm/damon/sysfs-common.h
index 745a918b94f5..56e6a99e353b 100644
--- a/mm/damon/sysfs-common.h
+++ b/mm/damon/sysfs-common.h
@@ -9,3 +9,16 @@
 #include <linux/kobject.h>
 
 extern struct mutex damon_sysfs_lock;
+
+struct damon_sysfs_ul_range {
+	struct kobject kobj;
+	unsigned long min;
+	unsigned long max;
+};
+
+struct damon_sysfs_ul_range *damon_sysfs_ul_range_alloc(
+		unsigned long min,
+		unsigned long max);
+void damon_sysfs_ul_range_release(struct kobject *kobj);
+
+extern struct kobj_type damon_sysfs_ul_range_ktype;
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 0f3f06d8dae7..129743292e17 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -11,106 +11,6 @@
 
 #include "sysfs-common.h"
 
-/*
- * unsigned long range directory
- */
-
-struct damon_sysfs_ul_range {
-	struct kobject kobj;
-	unsigned long min;
-	unsigned long max;
-};
-
-static struct damon_sysfs_ul_range *damon_sysfs_ul_range_alloc(
-		unsigned long min,
-		unsigned long max)
-{
-	struct damon_sysfs_ul_range *range = kmalloc(sizeof(*range),
-			GFP_KERNEL);
-
-	if (!range)
-		return NULL;
-	range->kobj = (struct kobject){};
-	range->min = min;
-	range->max = max;
-
-	return range;
-}
-
-static ssize_t min_show(struct kobject *kobj, struct kobj_attribute *attr,
-		char *buf)
-{
-	struct damon_sysfs_ul_range *range = container_of(kobj,
-			struct damon_sysfs_ul_range, kobj);
-
-	return sysfs_emit(buf, "%lu\n", range->min);
-}
-
-static ssize_t min_store(struct kobject *kobj, struct kobj_attribute *attr,
-		const char *buf, size_t count)
-{
-	struct damon_sysfs_ul_range *range = container_of(kobj,
-			struct damon_sysfs_ul_range, kobj);
-	unsigned long min;
-	int err;
-
-	err = kstrtoul(buf, 0, &min);
-	if (err)
-		return err;
-
-	range->min = min;
-	return count;
-}
-
-static ssize_t max_show(struct kobject *kobj, struct kobj_attribute *attr,
-		char *buf)
-{
-	struct damon_sysfs_ul_range *range = container_of(kobj,
-			struct damon_sysfs_ul_range, kobj);
-
-	return sysfs_emit(buf, "%lu\n", range->max);
-}
-
-static ssize_t max_store(struct kobject *kobj, struct kobj_attribute *attr,
-		const char *buf, size_t count)
-{
-	struct damon_sysfs_ul_range *range = container_of(kobj,
-			struct damon_sysfs_ul_range, kobj);
-	unsigned long max;
-	int err;
-
-	err = kstrtoul(buf, 0, &max);
-	if (err)
-		return err;
-
-	range->max = max;
-	return count;
-}
-
-static void damon_sysfs_ul_range_release(struct kobject *kobj)
-{
-	kfree(container_of(kobj, struct damon_sysfs_ul_range, kobj));
-}
-
-static struct kobj_attribute damon_sysfs_ul_range_min_attr =
-		__ATTR_RW_MODE(min, 0600);
-
-static struct kobj_attribute damon_sysfs_ul_range_max_attr =
-		__ATTR_RW_MODE(max, 0600);
-
-static struct attribute *damon_sysfs_ul_range_attrs[] = {
-	&damon_sysfs_ul_range_min_attr.attr,
-	&damon_sysfs_ul_range_max_attr.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(damon_sysfs_ul_range);
-
-static struct kobj_type damon_sysfs_ul_range_ktype = {
-	.release = damon_sysfs_ul_range_release,
-	.sysfs_ops = &kobj_sysfs_ops,
-	.default_groups = damon_sysfs_ul_range_groups,
-};
-
 /*
  * schemes/stats directory
  */
-- 
2.25.1

[RFC PATCH 11/18] mm/damon/sysfs: split out kdamond-independent schemes stats update logic into a new function

[SeongJae Park]

'damon_sysfs_schemes_update_stats()' is coupled with both
damon_sysfs_kdamond and damon_sysfs_schemes.  It's a wide range of types
dependency.  It makes splitting the logics a little bit distracting.
Split the function so that each function is coupled with smaller range
of types.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 35 +++++++++++++++++++++--------------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 129743292e17..082c55e68e0e 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -2204,6 +2204,25 @@ static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
 	mutex_unlock(&ctx->kdamond_lock);
 }
 
+static void damon_sysfs_schemes_update_stats(
+		struct damon_sysfs_schemes *sysfs_schemes,
+		struct damon_ctx *ctx)
+{
+	struct damos *scheme;
+	int schemes_idx = 0;
+
+	damon_for_each_scheme(scheme, ctx) {
+		struct damon_sysfs_stats *sysfs_stats;
+
+		sysfs_stats = sysfs_schemes->schemes_arr[schemes_idx++]->stats;
+		sysfs_stats->nr_tried = scheme->stat.nr_tried;
+		sysfs_stats->sz_tried = scheme->stat.sz_tried;
+		sysfs_stats->nr_applied = scheme->stat.nr_applied;
+		sysfs_stats->sz_applied = scheme->stat.sz_applied;
+		sysfs_stats->qt_exceeds = scheme->stat.qt_exceeds;
+	}
+}
+
 /*
  * damon_sysfs_upd_schemes_stats() - Update schemes stats sysfs files.
  * @kdamond:	The kobject wrapper that associated to the kdamond thread.
@@ -2216,23 +2235,11 @@ static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
 static int damon_sysfs_upd_schemes_stats(struct damon_sysfs_kdamond *kdamond)
 {
 	struct damon_ctx *ctx = kdamond->damon_ctx;
-	struct damon_sysfs_schemes *sysfs_schemes;
-	struct damos *scheme;
-	int schemes_idx = 0;
 
 	if (!ctx)
 		return -EINVAL;
-	sysfs_schemes = kdamond->contexts->contexts_arr[0]->schemes;
-	damon_for_each_scheme(scheme, ctx) {
-		struct damon_sysfs_stats *sysfs_stats;
-
-		sysfs_stats = sysfs_schemes->schemes_arr[schemes_idx++]->stats;
-		sysfs_stats->nr_tried = scheme->stat.nr_tried;
-		sysfs_stats->sz_tried = scheme->stat.sz_tried;
-		sysfs_stats->nr_applied = scheme->stat.nr_applied;
-		sysfs_stats->sz_applied = scheme->stat.sz_applied;
-		sysfs_stats->qt_exceeds = scheme->stat.qt_exceeds;
-	}
+	damon_sysfs_schemes_update_stats(
+			kdamond->contexts->contexts_arr[0]->schemes, ctx);
 	return 0;
 }
 
-- 
2.25.1

[RFC PATCH 12/18] mm/damon/sysfs: move schemes directory implementation to separate module

[SeongJae Park]

DAMON sysfs interface for 'schemes' directory is implemented using about
thousand lines of code.  It has no strong dependency with other parts of
its file, so split it out to another file for better code management.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/Makefile        |    2 +-
 mm/damon/sysfs-common.h  |   22 +
 mm/damon/sysfs-schemes.c | 1022 ++++++++++++++++++++++++++++++++++++++
 mm/damon/sysfs.c         | 1018 -------------------------------------
 4 files changed, 1045 insertions(+), 1019 deletions(-)
 create mode 100644 mm/damon/sysfs-schemes.c

diff --git a/mm/damon/Makefile b/mm/damon/Makefile
index 50d6b2ab3956..f7add3f4aa79 100644
--- a/mm/damon/Makefile
+++ b/mm/damon/Makefile
@@ -3,7 +3,7 @@
 obj-y				:= core.o
 obj-$(CONFIG_DAMON_VADDR)	+= ops-common.o vaddr.o
 obj-$(CONFIG_DAMON_PADDR)	+= ops-common.o paddr.o
-obj-$(CONFIG_DAMON_SYSFS)	+= sysfs-common.o sysfs.o
+obj-$(CONFIG_DAMON_SYSFS)	+= sysfs-common.o sysfs-schemes.o sysfs.o
 obj-$(CONFIG_DAMON_DBGFS)	+= dbgfs.o
 obj-$(CONFIG_DAMON_RECLAIM)	+= modules-common.o reclaim.o
 obj-$(CONFIG_DAMON_LRU_SORT)	+= modules-common.o lru_sort.o
diff --git a/mm/damon/sysfs-common.h b/mm/damon/sysfs-common.h
index 56e6a99e353b..4626b2784404 100644
--- a/mm/damon/sysfs-common.h
+++ b/mm/damon/sysfs-common.h
@@ -22,3 +22,25 @@ struct damon_sysfs_ul_range *damon_sysfs_ul_range_alloc(
 void damon_sysfs_ul_range_release(struct kobject *kobj);
 
 extern struct kobj_type damon_sysfs_ul_range_ktype;
+
+/*
+ * schemes directory
+ */
+
+struct damon_sysfs_schemes {
+	struct kobject kobj;
+	struct damon_sysfs_scheme **schemes_arr;
+	int nr;
+};
+
+struct damon_sysfs_schemes *damon_sysfs_schemes_alloc(void);
+void damon_sysfs_schemes_rm_dirs(struct damon_sysfs_schemes *schemes);
+
+extern struct kobj_type damon_sysfs_schemes_ktype;
+
+int damon_sysfs_set_schemes(struct damon_ctx *ctx,
+		struct damon_sysfs_schemes *sysfs_schemes);
+
+void damon_sysfs_schemes_update_stats(
+		struct damon_sysfs_schemes *sysfs_schemes,
+		struct damon_ctx *ctx);
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
new file mode 100644
index 000000000000..7ea4bcce90cb
--- /dev/null
+++ b/mm/damon/sysfs-schemes.c
@@ -0,0 +1,1022 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DAMON sysfs Interface
+ *
+ * Copyright (c) 2022 SeongJae Park <sj@kernel.org>
+ */
+
+#include <linux/slab.h>
+
+#include "sysfs-common.h"
+
+/*
+ * schemes/stats directory
+ */
+
+struct damon_sysfs_stats {
+	struct kobject kobj;
+	unsigned long nr_tried;
+	unsigned long sz_tried;
+	unsigned long nr_applied;
+	unsigned long sz_applied;
+	unsigned long qt_exceeds;
+};
+
+static struct damon_sysfs_stats *damon_sysfs_stats_alloc(void)
+{
+	return kzalloc(sizeof(struct damon_sysfs_stats), GFP_KERNEL);
+}
+
+static ssize_t nr_tried_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_stats *stats = container_of(kobj,
+			struct damon_sysfs_stats, kobj);
+
+	return sysfs_emit(buf, "%lu\n", stats->nr_tried);
+}
+
+static ssize_t sz_tried_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_stats *stats = container_of(kobj,
+			struct damon_sysfs_stats, kobj);
+
+	return sysfs_emit(buf, "%lu\n", stats->sz_tried);
+}
+
+static ssize_t nr_applied_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_stats *stats = container_of(kobj,
+			struct damon_sysfs_stats, kobj);
+
+	return sysfs_emit(buf, "%lu\n", stats->nr_applied);
+}
+
+static ssize_t sz_applied_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_stats *stats = container_of(kobj,
+			struct damon_sysfs_stats, kobj);
+
+	return sysfs_emit(buf, "%lu\n", stats->sz_applied);
+}
+
+static ssize_t qt_exceeds_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_stats *stats = container_of(kobj,
+			struct damon_sysfs_stats, kobj);
+
+	return sysfs_emit(buf, "%lu\n", stats->qt_exceeds);
+}
+
+static void damon_sysfs_stats_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_stats, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_stats_nr_tried_attr =
+		__ATTR_RO_MODE(nr_tried, 0400);
+
+static struct kobj_attribute damon_sysfs_stats_sz_tried_attr =
+		__ATTR_RO_MODE(sz_tried, 0400);
+
+static struct kobj_attribute damon_sysfs_stats_nr_applied_attr =
+		__ATTR_RO_MODE(nr_applied, 0400);
+
+static struct kobj_attribute damon_sysfs_stats_sz_applied_attr =
+		__ATTR_RO_MODE(sz_applied, 0400);
+
+static struct kobj_attribute damon_sysfs_stats_qt_exceeds_attr =
+		__ATTR_RO_MODE(qt_exceeds, 0400);
+
+static struct attribute *damon_sysfs_stats_attrs[] = {
+	&damon_sysfs_stats_nr_tried_attr.attr,
+	&damon_sysfs_stats_sz_tried_attr.attr,
+	&damon_sysfs_stats_nr_applied_attr.attr,
+	&damon_sysfs_stats_sz_applied_attr.attr,
+	&damon_sysfs_stats_qt_exceeds_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_stats);
+
+static struct kobj_type damon_sysfs_stats_ktype = {
+	.release = damon_sysfs_stats_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_stats_groups,
+};
+
+/*
+ * watermarks directory
+ */
+
+struct damon_sysfs_watermarks {
+	struct kobject kobj;
+	enum damos_wmark_metric metric;
+	unsigned long interval_us;
+	unsigned long high;
+	unsigned long mid;
+	unsigned long low;
+};
+
+static struct damon_sysfs_watermarks *damon_sysfs_watermarks_alloc(
+		enum damos_wmark_metric metric, unsigned long interval_us,
+		unsigned long high, unsigned long mid, unsigned long low)
+{
+	struct damon_sysfs_watermarks *watermarks = kmalloc(
+			sizeof(*watermarks), GFP_KERNEL);
+
+	if (!watermarks)
+		return NULL;
+	watermarks->kobj = (struct kobject){};
+	watermarks->metric = metric;
+	watermarks->interval_us = interval_us;
+	watermarks->high = high;
+	watermarks->mid = mid;
+	watermarks->low = low;
+	return watermarks;
+}
+
+/* Should match with enum damos_wmark_metric */
+static const char * const damon_sysfs_wmark_metric_strs[] = {
+	"none",
+	"free_mem_rate",
+};
+
+static ssize_t metric_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+
+	return sysfs_emit(buf, "%s\n",
+			damon_sysfs_wmark_metric_strs[watermarks->metric]);
+}
+
+static ssize_t metric_store(struct kobject *kobj, struct kobj_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+	enum damos_wmark_metric metric;
+
+	for (metric = 0; metric < NR_DAMOS_WMARK_METRICS; metric++) {
+		if (sysfs_streq(buf, damon_sysfs_wmark_metric_strs[metric])) {
+			watermarks->metric = metric;
+			return count;
+		}
+	}
+	return -EINVAL;
+}
+
+static ssize_t interval_us_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+
+	return sysfs_emit(buf, "%lu\n", watermarks->interval_us);
+}
+
+static ssize_t interval_us_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+	int err = kstrtoul(buf, 0, &watermarks->interval_us);
+
+	return err ? err : count;
+}
+
+static ssize_t high_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+
+	return sysfs_emit(buf, "%lu\n", watermarks->high);
+}
+
+static ssize_t high_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+	int err = kstrtoul(buf, 0, &watermarks->high);
+
+	return err ? err : count;
+}
+
+static ssize_t mid_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+
+	return sysfs_emit(buf, "%lu\n", watermarks->mid);
+}
+
+static ssize_t mid_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+	int err = kstrtoul(buf, 0, &watermarks->mid);
+
+	return err ? err : count;
+}
+
+static ssize_t low_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+
+	return sysfs_emit(buf, "%lu\n", watermarks->low);
+}
+
+static ssize_t low_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
+			struct damon_sysfs_watermarks, kobj);
+	int err = kstrtoul(buf, 0, &watermarks->low);
+
+	return err ? err : count;
+}
+
+static void damon_sysfs_watermarks_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_watermarks, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_watermarks_metric_attr =
+		__ATTR_RW_MODE(metric, 0600);
+
+static struct kobj_attribute damon_sysfs_watermarks_interval_us_attr =
+		__ATTR_RW_MODE(interval_us, 0600);
+
+static struct kobj_attribute damon_sysfs_watermarks_high_attr =
+		__ATTR_RW_MODE(high, 0600);
+
+static struct kobj_attribute damon_sysfs_watermarks_mid_attr =
+		__ATTR_RW_MODE(mid, 0600);
+
+static struct kobj_attribute damon_sysfs_watermarks_low_attr =
+		__ATTR_RW_MODE(low, 0600);
+
+static struct attribute *damon_sysfs_watermarks_attrs[] = {
+	&damon_sysfs_watermarks_metric_attr.attr,
+	&damon_sysfs_watermarks_interval_us_attr.attr,
+	&damon_sysfs_watermarks_high_attr.attr,
+	&damon_sysfs_watermarks_mid_attr.attr,
+	&damon_sysfs_watermarks_low_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_watermarks);
+
+static struct kobj_type damon_sysfs_watermarks_ktype = {
+	.release = damon_sysfs_watermarks_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_watermarks_groups,
+};
+
+/*
+ * scheme/weights directory
+ */
+
+struct damon_sysfs_weights {
+	struct kobject kobj;
+	unsigned int sz;
+	unsigned int nr_accesses;
+	unsigned int age;
+};
+
+static struct damon_sysfs_weights *damon_sysfs_weights_alloc(unsigned int sz,
+		unsigned int nr_accesses, unsigned int age)
+{
+	struct damon_sysfs_weights *weights = kmalloc(sizeof(*weights),
+			GFP_KERNEL);
+
+	if (!weights)
+		return NULL;
+	weights->kobj = (struct kobject){};
+	weights->sz = sz;
+	weights->nr_accesses = nr_accesses;
+	weights->age = age;
+	return weights;
+}
+
+static ssize_t sz_permil_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_weights *weights = container_of(kobj,
+			struct damon_sysfs_weights, kobj);
+
+	return sysfs_emit(buf, "%u\n", weights->sz);
+}
+
+static ssize_t sz_permil_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_weights *weights = container_of(kobj,
+			struct damon_sysfs_weights, kobj);
+	int err = kstrtouint(buf, 0, &weights->sz);
+
+	return err ? err : count;
+}
+
+static ssize_t nr_accesses_permil_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_weights *weights = container_of(kobj,
+			struct damon_sysfs_weights, kobj);
+
+	return sysfs_emit(buf, "%u\n", weights->nr_accesses);
+}
+
+static ssize_t nr_accesses_permil_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_weights *weights = container_of(kobj,
+			struct damon_sysfs_weights, kobj);
+	int err = kstrtouint(buf, 0, &weights->nr_accesses);
+
+	return err ? err : count;
+}
+
+static ssize_t age_permil_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_weights *weights = container_of(kobj,
+			struct damon_sysfs_weights, kobj);
+
+	return sysfs_emit(buf, "%u\n", weights->age);
+}
+
+static ssize_t age_permil_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_weights *weights = container_of(kobj,
+			struct damon_sysfs_weights, kobj);
+	int err = kstrtouint(buf, 0, &weights->age);
+
+	return err ? err : count;
+}
+
+static void damon_sysfs_weights_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_weights, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_weights_sz_attr =
+		__ATTR_RW_MODE(sz_permil, 0600);
+
+static struct kobj_attribute damon_sysfs_weights_nr_accesses_attr =
+		__ATTR_RW_MODE(nr_accesses_permil, 0600);
+
+static struct kobj_attribute damon_sysfs_weights_age_attr =
+		__ATTR_RW_MODE(age_permil, 0600);
+
+static struct attribute *damon_sysfs_weights_attrs[] = {
+	&damon_sysfs_weights_sz_attr.attr,
+	&damon_sysfs_weights_nr_accesses_attr.attr,
+	&damon_sysfs_weights_age_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_weights);
+
+static struct kobj_type damon_sysfs_weights_ktype = {
+	.release = damon_sysfs_weights_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_weights_groups,
+};
+
+/*
+ * quotas directory
+ */
+
+struct damon_sysfs_quotas {
+	struct kobject kobj;
+	struct damon_sysfs_weights *weights;
+	unsigned long ms;
+	unsigned long sz;
+	unsigned long reset_interval_ms;
+};
+
+static struct damon_sysfs_quotas *damon_sysfs_quotas_alloc(void)
+{
+	return kzalloc(sizeof(struct damon_sysfs_quotas), GFP_KERNEL);
+}
+
+static int damon_sysfs_quotas_add_dirs(struct damon_sysfs_quotas *quotas)
+{
+	struct damon_sysfs_weights *weights;
+	int err;
+
+	weights = damon_sysfs_weights_alloc(0, 0, 0);
+	if (!weights)
+		return -ENOMEM;
+
+	err = kobject_init_and_add(&weights->kobj, &damon_sysfs_weights_ktype,
+			&quotas->kobj, "weights");
+	if (err)
+		kobject_put(&weights->kobj);
+	else
+		quotas->weights = weights;
+	return err;
+}
+
+static void damon_sysfs_quotas_rm_dirs(struct damon_sysfs_quotas *quotas)
+{
+	kobject_put(&quotas->weights->kobj);
+}
+
+static ssize_t ms_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+
+	return sysfs_emit(buf, "%lu\n", quotas->ms);
+}
+
+static ssize_t ms_store(struct kobject *kobj, struct kobj_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+	int err = kstrtoul(buf, 0, &quotas->ms);
+
+	if (err)
+		return -EINVAL;
+	return count;
+}
+
+static ssize_t bytes_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+
+	return sysfs_emit(buf, "%lu\n", quotas->sz);
+}
+
+static ssize_t bytes_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+	int err = kstrtoul(buf, 0, &quotas->sz);
+
+	if (err)
+		return -EINVAL;
+	return count;
+}
+
+static ssize_t reset_interval_ms_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+
+	return sysfs_emit(buf, "%lu\n", quotas->reset_interval_ms);
+}
+
+static ssize_t reset_interval_ms_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+	int err = kstrtoul(buf, 0, &quotas->reset_interval_ms);
+
+	if (err)
+		return -EINVAL;
+	return count;
+}
+
+static void damon_sysfs_quotas_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_quotas, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_quotas_ms_attr =
+		__ATTR_RW_MODE(ms, 0600);
+
+static struct kobj_attribute damon_sysfs_quotas_sz_attr =
+		__ATTR_RW_MODE(bytes, 0600);
+
+static struct kobj_attribute damon_sysfs_quotas_reset_interval_ms_attr =
+		__ATTR_RW_MODE(reset_interval_ms, 0600);
+
+static struct attribute *damon_sysfs_quotas_attrs[] = {
+	&damon_sysfs_quotas_ms_attr.attr,
+	&damon_sysfs_quotas_sz_attr.attr,
+	&damon_sysfs_quotas_reset_interval_ms_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_quotas);
+
+static struct kobj_type damon_sysfs_quotas_ktype = {
+	.release = damon_sysfs_quotas_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_quotas_groups,
+};
+
+/*
+ * access_pattern directory
+ */
+
+struct damon_sysfs_access_pattern {
+	struct kobject kobj;
+	struct damon_sysfs_ul_range *sz;
+	struct damon_sysfs_ul_range *nr_accesses;
+	struct damon_sysfs_ul_range *age;
+};
+
+static
+struct damon_sysfs_access_pattern *damon_sysfs_access_pattern_alloc(void)
+{
+	struct damon_sysfs_access_pattern *access_pattern =
+		kmalloc(sizeof(*access_pattern), GFP_KERNEL);
+
+	if (!access_pattern)
+		return NULL;
+	access_pattern->kobj = (struct kobject){};
+	return access_pattern;
+}
+
+static int damon_sysfs_access_pattern_add_range_dir(
+		struct damon_sysfs_access_pattern *access_pattern,
+		struct damon_sysfs_ul_range **range_dir_ptr,
+		char *name)
+{
+	struct damon_sysfs_ul_range *range = damon_sysfs_ul_range_alloc(0, 0);
+	int err;
+
+	if (!range)
+		return -ENOMEM;
+	err = kobject_init_and_add(&range->kobj, &damon_sysfs_ul_range_ktype,
+			&access_pattern->kobj, name);
+	if (err)
+		kobject_put(&range->kobj);
+	else
+		*range_dir_ptr = range;
+	return err;
+}
+
+static int damon_sysfs_access_pattern_add_dirs(
+		struct damon_sysfs_access_pattern *access_pattern)
+{
+	int err;
+
+	err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
+			&access_pattern->sz, "sz");
+	if (err)
+		goto put_sz_out;
+
+	err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
+			&access_pattern->nr_accesses, "nr_accesses");
+	if (err)
+		goto put_nr_accesses_sz_out;
+
+	err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
+			&access_pattern->age, "age");
+	if (err)
+		goto put_age_nr_accesses_sz_out;
+	return 0;
+
+put_age_nr_accesses_sz_out:
+	kobject_put(&access_pattern->age->kobj);
+	access_pattern->age = NULL;
+put_nr_accesses_sz_out:
+	kobject_put(&access_pattern->nr_accesses->kobj);
+	access_pattern->nr_accesses = NULL;
+put_sz_out:
+	kobject_put(&access_pattern->sz->kobj);
+	access_pattern->sz = NULL;
+	return err;
+}
+
+static void damon_sysfs_access_pattern_rm_dirs(
+		struct damon_sysfs_access_pattern *access_pattern)
+{
+	kobject_put(&access_pattern->sz->kobj);
+	kobject_put(&access_pattern->nr_accesses->kobj);
+	kobject_put(&access_pattern->age->kobj);
+}
+
+static void damon_sysfs_access_pattern_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_access_pattern, kobj));
+}
+
+static struct attribute *damon_sysfs_access_pattern_attrs[] = {
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_access_pattern);
+
+static struct kobj_type damon_sysfs_access_pattern_ktype = {
+	.release = damon_sysfs_access_pattern_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_access_pattern_groups,
+};
+
+/*
+ * scheme directory
+ */
+
+struct damon_sysfs_scheme {
+	struct kobject kobj;
+	enum damos_action action;
+	struct damon_sysfs_access_pattern *access_pattern;
+	struct damon_sysfs_quotas *quotas;
+	struct damon_sysfs_watermarks *watermarks;
+	struct damon_sysfs_stats *stats;
+};
+
+/* This should match with enum damos_action */
+static const char * const damon_sysfs_damos_action_strs[] = {
+	"willneed",
+	"cold",
+	"pageout",
+	"hugepage",
+	"nohugepage",
+	"lru_prio",
+	"lru_deprio",
+	"stat",
+};
+
+static struct damon_sysfs_scheme *damon_sysfs_scheme_alloc(
+		enum damos_action action)
+{
+	struct damon_sysfs_scheme *scheme = kmalloc(sizeof(*scheme),
+				GFP_KERNEL);
+
+	if (!scheme)
+		return NULL;
+	scheme->kobj = (struct kobject){};
+	scheme->action = action;
+	return scheme;
+}
+
+static int damon_sysfs_scheme_set_access_pattern(
+		struct damon_sysfs_scheme *scheme)
+{
+	struct damon_sysfs_access_pattern *access_pattern;
+	int err;
+
+	access_pattern = damon_sysfs_access_pattern_alloc();
+	if (!access_pattern)
+		return -ENOMEM;
+	err = kobject_init_and_add(&access_pattern->kobj,
+			&damon_sysfs_access_pattern_ktype, &scheme->kobj,
+			"access_pattern");
+	if (err)
+		goto out;
+	err = damon_sysfs_access_pattern_add_dirs(access_pattern);
+	if (err)
+		goto out;
+	scheme->access_pattern = access_pattern;
+	return 0;
+
+out:
+	kobject_put(&access_pattern->kobj);
+	return err;
+}
+
+static int damon_sysfs_scheme_set_quotas(struct damon_sysfs_scheme *scheme)
+{
+	struct damon_sysfs_quotas *quotas = damon_sysfs_quotas_alloc();
+	int err;
+
+	if (!quotas)
+		return -ENOMEM;
+	err = kobject_init_and_add(&quotas->kobj, &damon_sysfs_quotas_ktype,
+			&scheme->kobj, "quotas");
+	if (err)
+		goto out;
+	err = damon_sysfs_quotas_add_dirs(quotas);
+	if (err)
+		goto out;
+	scheme->quotas = quotas;
+	return 0;
+
+out:
+	kobject_put(&quotas->kobj);
+	return err;
+}
+
+static int damon_sysfs_scheme_set_watermarks(struct damon_sysfs_scheme *scheme)
+{
+	struct damon_sysfs_watermarks *watermarks =
+		damon_sysfs_watermarks_alloc(DAMOS_WMARK_NONE, 0, 0, 0, 0);
+	int err;
+
+	if (!watermarks)
+		return -ENOMEM;
+	err = kobject_init_and_add(&watermarks->kobj,
+			&damon_sysfs_watermarks_ktype, &scheme->kobj,
+			"watermarks");
+	if (err)
+		kobject_put(&watermarks->kobj);
+	else
+		scheme->watermarks = watermarks;
+	return err;
+}
+
+static int damon_sysfs_scheme_set_stats(struct damon_sysfs_scheme *scheme)
+{
+	struct damon_sysfs_stats *stats = damon_sysfs_stats_alloc();
+	int err;
+
+	if (!stats)
+		return -ENOMEM;
+	err = kobject_init_and_add(&stats->kobj, &damon_sysfs_stats_ktype,
+			&scheme->kobj, "stats");
+	if (err)
+		kobject_put(&stats->kobj);
+	else
+		scheme->stats = stats;
+	return err;
+}
+
+static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
+{
+	int err;
+
+	err = damon_sysfs_scheme_set_access_pattern(scheme);
+	if (err)
+		return err;
+	err = damon_sysfs_scheme_set_quotas(scheme);
+	if (err)
+		goto put_access_pattern_out;
+	err = damon_sysfs_scheme_set_watermarks(scheme);
+	if (err)
+		goto put_quotas_access_pattern_out;
+	err = damon_sysfs_scheme_set_stats(scheme);
+	if (err)
+		goto put_watermarks_quotas_access_pattern_out;
+	return 0;
+
+put_watermarks_quotas_access_pattern_out:
+	kobject_put(&scheme->watermarks->kobj);
+	scheme->watermarks = NULL;
+put_quotas_access_pattern_out:
+	kobject_put(&scheme->quotas->kobj);
+	scheme->quotas = NULL;
+put_access_pattern_out:
+	kobject_put(&scheme->access_pattern->kobj);
+	scheme->access_pattern = NULL;
+	return err;
+}
+
+static void damon_sysfs_scheme_rm_dirs(struct damon_sysfs_scheme *scheme)
+{
+	damon_sysfs_access_pattern_rm_dirs(scheme->access_pattern);
+	kobject_put(&scheme->access_pattern->kobj);
+	damon_sysfs_quotas_rm_dirs(scheme->quotas);
+	kobject_put(&scheme->quotas->kobj);
+	kobject_put(&scheme->watermarks->kobj);
+	kobject_put(&scheme->stats->kobj);
+}
+
+static ssize_t action_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_scheme *scheme = container_of(kobj,
+			struct damon_sysfs_scheme, kobj);
+
+	return sysfs_emit(buf, "%s\n",
+			damon_sysfs_damos_action_strs[scheme->action]);
+}
+
+static ssize_t action_store(struct kobject *kobj, struct kobj_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct damon_sysfs_scheme *scheme = container_of(kobj,
+			struct damon_sysfs_scheme, kobj);
+	enum damos_action action;
+
+	for (action = 0; action < NR_DAMOS_ACTIONS; action++) {
+		if (sysfs_streq(buf, damon_sysfs_damos_action_strs[action])) {
+			scheme->action = action;
+			return count;
+		}
+	}
+	return -EINVAL;
+}
+
+static void damon_sysfs_scheme_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_scheme, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_scheme_action_attr =
+		__ATTR_RW_MODE(action, 0600);
+
+static struct attribute *damon_sysfs_scheme_attrs[] = {
+	&damon_sysfs_scheme_action_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_scheme);
+
+static struct kobj_type damon_sysfs_scheme_ktype = {
+	.release = damon_sysfs_scheme_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_scheme_groups,
+};
+
+/*
+ * schemes directory
+ */
+
+struct damon_sysfs_schemes *damon_sysfs_schemes_alloc(void)
+{
+	return kzalloc(sizeof(struct damon_sysfs_schemes), GFP_KERNEL);
+}
+
+void damon_sysfs_schemes_rm_dirs(struct damon_sysfs_schemes *schemes)
+{
+	struct damon_sysfs_scheme **schemes_arr = schemes->schemes_arr;
+	int i;
+
+	for (i = 0; i < schemes->nr; i++) {
+		damon_sysfs_scheme_rm_dirs(schemes_arr[i]);
+		kobject_put(&schemes_arr[i]->kobj);
+	}
+	schemes->nr = 0;
+	kfree(schemes_arr);
+	schemes->schemes_arr = NULL;
+}
+
+static int damon_sysfs_schemes_add_dirs(struct damon_sysfs_schemes *schemes,
+		int nr_schemes)
+{
+	struct damon_sysfs_scheme **schemes_arr, *scheme;
+	int err, i;
+
+	damon_sysfs_schemes_rm_dirs(schemes);
+	if (!nr_schemes)
+		return 0;
+
+	schemes_arr = kmalloc_array(nr_schemes, sizeof(*schemes_arr),
+			GFP_KERNEL | __GFP_NOWARN);
+	if (!schemes_arr)
+		return -ENOMEM;
+	schemes->schemes_arr = schemes_arr;
+
+	for (i = 0; i < nr_schemes; i++) {
+		scheme = damon_sysfs_scheme_alloc(DAMOS_STAT);
+		if (!scheme) {
+			damon_sysfs_schemes_rm_dirs(schemes);
+			return -ENOMEM;
+		}
+
+		err = kobject_init_and_add(&scheme->kobj,
+				&damon_sysfs_scheme_ktype, &schemes->kobj,
+				"%d", i);
+		if (err)
+			goto out;
+		err = damon_sysfs_scheme_add_dirs(scheme);
+		if (err)
+			goto out;
+
+		schemes_arr[i] = scheme;
+		schemes->nr++;
+	}
+	return 0;
+
+out:
+	damon_sysfs_schemes_rm_dirs(schemes);
+	kobject_put(&scheme->kobj);
+	return err;
+}
+
+static ssize_t nr_schemes_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_schemes *schemes = container_of(kobj,
+			struct damon_sysfs_schemes, kobj);
+
+	return sysfs_emit(buf, "%d\n", schemes->nr);
+}
+
+static ssize_t nr_schemes_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_schemes *schemes;
+	int nr, err = kstrtoint(buf, 0, &nr);
+
+	if (err)
+		return err;
+	if (nr < 0)
+		return -EINVAL;
+
+	schemes = container_of(kobj, struct damon_sysfs_schemes, kobj);
+
+	if (!mutex_trylock(&damon_sysfs_lock))
+		return -EBUSY;
+	err = damon_sysfs_schemes_add_dirs(schemes, nr);
+	mutex_unlock(&damon_sysfs_lock);
+	if (err)
+		return err;
+	return count;
+}
+
+static void damon_sysfs_schemes_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_schemes, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_schemes_nr_attr =
+		__ATTR_RW_MODE(nr_schemes, 0600);
+
+static struct attribute *damon_sysfs_schemes_attrs[] = {
+	&damon_sysfs_schemes_nr_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_schemes);
+
+struct kobj_type damon_sysfs_schemes_ktype = {
+	.release = damon_sysfs_schemes_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_schemes_groups,
+};
+
+static struct damos *damon_sysfs_mk_scheme(
+		struct damon_sysfs_scheme *sysfs_scheme)
+{
+	struct damon_sysfs_access_pattern *access_pattern =
+		sysfs_scheme->access_pattern;
+	struct damon_sysfs_quotas *sysfs_quotas = sysfs_scheme->quotas;
+	struct damon_sysfs_weights *sysfs_weights = sysfs_quotas->weights;
+	struct damon_sysfs_watermarks *sysfs_wmarks = sysfs_scheme->watermarks;
+
+	struct damos_access_pattern pattern = {
+		.min_sz_region = access_pattern->sz->min,
+		.max_sz_region = access_pattern->sz->max,
+		.min_nr_accesses = access_pattern->nr_accesses->min,
+		.max_nr_accesses = access_pattern->nr_accesses->max,
+		.min_age_region = access_pattern->age->min,
+		.max_age_region = access_pattern->age->max,
+	};
+	struct damos_quota quota = {
+		.ms = sysfs_quotas->ms,
+		.sz = sysfs_quotas->sz,
+		.reset_interval = sysfs_quotas->reset_interval_ms,
+		.weight_sz = sysfs_weights->sz,
+		.weight_nr_accesses = sysfs_weights->nr_accesses,
+		.weight_age = sysfs_weights->age,
+	};
+	struct damos_watermarks wmarks = {
+		.metric = sysfs_wmarks->metric,
+		.interval = sysfs_wmarks->interval_us,
+		.high = sysfs_wmarks->high,
+		.mid = sysfs_wmarks->mid,
+		.low = sysfs_wmarks->low,
+	};
+
+	return damon_new_scheme(&pattern, sysfs_scheme->action, &quota,
+			&wmarks);
+}
+
+int damon_sysfs_set_schemes(struct damon_ctx *ctx,
+		struct damon_sysfs_schemes *sysfs_schemes)
+{
+	int i;
+
+	for (i = 0; i < sysfs_schemes->nr; i++) {
+		struct damos *scheme, *next;
+
+		scheme = damon_sysfs_mk_scheme(sysfs_schemes->schemes_arr[i]);
+		if (!scheme) {
+			damon_for_each_scheme_safe(scheme, next, ctx)
+				damon_destroy_scheme(scheme);
+			return -ENOMEM;
+		}
+		damon_add_scheme(ctx, scheme);
+	}
+	return 0;
+}
+
+void damon_sysfs_schemes_update_stats(
+		struct damon_sysfs_schemes *sysfs_schemes,
+		struct damon_ctx *ctx)
+{
+	struct damos *scheme;
+	int schemes_idx = 0;
+
+	damon_for_each_scheme(scheme, ctx) {
+		struct damon_sysfs_stats *sysfs_stats;
+
+		sysfs_stats = sysfs_schemes->schemes_arr[schemes_idx++]->stats;
+		sysfs_stats->nr_tried = scheme->stat.nr_tried;
+		sysfs_stats->sz_tried = scheme->stat.sz_tried;
+		sysfs_stats->nr_applied = scheme->stat.nr_applied;
+		sysfs_stats->sz_applied = scheme->stat.sz_applied;
+		sysfs_stats->qt_exceeds = scheme->stat.qt_exceeds;
+	}
+}
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 082c55e68e0e..284daf274b3e 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -11,949 +11,6 @@
 
 #include "sysfs-common.h"
 
-/*
- * schemes/stats directory
- */
-
-struct damon_sysfs_stats {
-	struct kobject kobj;
-	unsigned long nr_tried;
-	unsigned long sz_tried;
-	unsigned long nr_applied;
-	unsigned long sz_applied;
-	unsigned long qt_exceeds;
-};
-
-static struct damon_sysfs_stats *damon_sysfs_stats_alloc(void)
-{
-	return kzalloc(sizeof(struct damon_sysfs_stats), GFP_KERNEL);
-}
-
-static ssize_t nr_tried_show(struct kobject *kobj, struct kobj_attribute *attr,
-		char *buf)
-{
-	struct damon_sysfs_stats *stats = container_of(kobj,
-			struct damon_sysfs_stats, kobj);
-
-	return sysfs_emit(buf, "%lu\n", stats->nr_tried);
-}
-
-static ssize_t sz_tried_show(struct kobject *kobj, struct kobj_attribute *attr,
-		char *buf)
-{
-	struct damon_sysfs_stats *stats = container_of(kobj,
-			struct damon_sysfs_stats, kobj);
-
-	return sysfs_emit(buf, "%lu\n", stats->sz_tried);
-}
-
-static ssize_t nr_applied_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_stats *stats = container_of(kobj,
-			struct damon_sysfs_stats, kobj);
-
-	return sysfs_emit(buf, "%lu\n", stats->nr_applied);
-}
-
-static ssize_t sz_applied_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_stats *stats = container_of(kobj,
-			struct damon_sysfs_stats, kobj);
-
-	return sysfs_emit(buf, "%lu\n", stats->sz_applied);
-}
-
-static ssize_t qt_exceeds_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_stats *stats = container_of(kobj,
-			struct damon_sysfs_stats, kobj);
-
-	return sysfs_emit(buf, "%lu\n", stats->qt_exceeds);
-}
-
-static void damon_sysfs_stats_release(struct kobject *kobj)
-{
-	kfree(container_of(kobj, struct damon_sysfs_stats, kobj));
-}
-
-static struct kobj_attribute damon_sysfs_stats_nr_tried_attr =
-		__ATTR_RO_MODE(nr_tried, 0400);
-
-static struct kobj_attribute damon_sysfs_stats_sz_tried_attr =
-		__ATTR_RO_MODE(sz_tried, 0400);
-
-static struct kobj_attribute damon_sysfs_stats_nr_applied_attr =
-		__ATTR_RO_MODE(nr_applied, 0400);
-
-static struct kobj_attribute damon_sysfs_stats_sz_applied_attr =
-		__ATTR_RO_MODE(sz_applied, 0400);
-
-static struct kobj_attribute damon_sysfs_stats_qt_exceeds_attr =
-		__ATTR_RO_MODE(qt_exceeds, 0400);
-
-static struct attribute *damon_sysfs_stats_attrs[] = {
-	&damon_sysfs_stats_nr_tried_attr.attr,
-	&damon_sysfs_stats_sz_tried_attr.attr,
-	&damon_sysfs_stats_nr_applied_attr.attr,
-	&damon_sysfs_stats_sz_applied_attr.attr,
-	&damon_sysfs_stats_qt_exceeds_attr.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(damon_sysfs_stats);
-
-static struct kobj_type damon_sysfs_stats_ktype = {
-	.release = damon_sysfs_stats_release,
-	.sysfs_ops = &kobj_sysfs_ops,
-	.default_groups = damon_sysfs_stats_groups,
-};
-
-/*
- * watermarks directory
- */
-
-struct damon_sysfs_watermarks {
-	struct kobject kobj;
-	enum damos_wmark_metric metric;
-	unsigned long interval_us;
-	unsigned long high;
-	unsigned long mid;
-	unsigned long low;
-};
-
-static struct damon_sysfs_watermarks *damon_sysfs_watermarks_alloc(
-		enum damos_wmark_metric metric, unsigned long interval_us,
-		unsigned long high, unsigned long mid, unsigned long low)
-{
-	struct damon_sysfs_watermarks *watermarks = kmalloc(
-			sizeof(*watermarks), GFP_KERNEL);
-
-	if (!watermarks)
-		return NULL;
-	watermarks->kobj = (struct kobject){};
-	watermarks->metric = metric;
-	watermarks->interval_us = interval_us;
-	watermarks->high = high;
-	watermarks->mid = mid;
-	watermarks->low = low;
-	return watermarks;
-}
-
-/* Should match with enum damos_wmark_metric */
-static const char * const damon_sysfs_wmark_metric_strs[] = {
-	"none",
-	"free_mem_rate",
-};
-
-static ssize_t metric_show(struct kobject *kobj, struct kobj_attribute *attr,
-		char *buf)
-{
-	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
-			struct damon_sysfs_watermarks, kobj);
-
-	return sysfs_emit(buf, "%s\n",
-			damon_sysfs_wmark_metric_strs[watermarks->metric]);
-}
-
-static ssize_t metric_store(struct kobject *kobj, struct kobj_attribute *attr,
-		const char *buf, size_t count)
-{
-	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
-			struct damon_sysfs_watermarks, kobj);
-	enum damos_wmark_metric metric;
-
-	for (metric = 0; metric < NR_DAMOS_WMARK_METRICS; metric++) {
-		if (sysfs_streq(buf, damon_sysfs_wmark_metric_strs[metric])) {
-			watermarks->metric = metric;
-			return count;
-		}
-	}
-	return -EINVAL;
-}
-
-static ssize_t interval_us_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
-			struct damon_sysfs_watermarks, kobj);
-
-	return sysfs_emit(buf, "%lu\n", watermarks->interval_us);
-}
-
-static ssize_t interval_us_store(struct kobject *kobj,
-		struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
-			struct damon_sysfs_watermarks, kobj);
-	int err = kstrtoul(buf, 0, &watermarks->interval_us);
-
-	return err ? err : count;
-}
-
-static ssize_t high_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
-			struct damon_sysfs_watermarks, kobj);
-
-	return sysfs_emit(buf, "%lu\n", watermarks->high);
-}
-
-static ssize_t high_store(struct kobject *kobj,
-		struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
-			struct damon_sysfs_watermarks, kobj);
-	int err = kstrtoul(buf, 0, &watermarks->high);
-
-	return err ? err : count;
-}
-
-static ssize_t mid_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
-			struct damon_sysfs_watermarks, kobj);
-
-	return sysfs_emit(buf, "%lu\n", watermarks->mid);
-}
-
-static ssize_t mid_store(struct kobject *kobj,
-		struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
-			struct damon_sysfs_watermarks, kobj);
-	int err = kstrtoul(buf, 0, &watermarks->mid);
-
-	return err ? err : count;
-}
-
-static ssize_t low_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
-			struct damon_sysfs_watermarks, kobj);
-
-	return sysfs_emit(buf, "%lu\n", watermarks->low);
-}
-
-static ssize_t low_store(struct kobject *kobj,
-		struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	struct damon_sysfs_watermarks *watermarks = container_of(kobj,
-			struct damon_sysfs_watermarks, kobj);
-	int err = kstrtoul(buf, 0, &watermarks->low);
-
-	return err ? err : count;
-}
-
-static void damon_sysfs_watermarks_release(struct kobject *kobj)
-{
-	kfree(container_of(kobj, struct damon_sysfs_watermarks, kobj));
-}
-
-static struct kobj_attribute damon_sysfs_watermarks_metric_attr =
-		__ATTR_RW_MODE(metric, 0600);
-
-static struct kobj_attribute damon_sysfs_watermarks_interval_us_attr =
-		__ATTR_RW_MODE(interval_us, 0600);
-
-static struct kobj_attribute damon_sysfs_watermarks_high_attr =
-		__ATTR_RW_MODE(high, 0600);
-
-static struct kobj_attribute damon_sysfs_watermarks_mid_attr =
-		__ATTR_RW_MODE(mid, 0600);
-
-static struct kobj_attribute damon_sysfs_watermarks_low_attr =
-		__ATTR_RW_MODE(low, 0600);
-
-static struct attribute *damon_sysfs_watermarks_attrs[] = {
-	&damon_sysfs_watermarks_metric_attr.attr,
-	&damon_sysfs_watermarks_interval_us_attr.attr,
-	&damon_sysfs_watermarks_high_attr.attr,
-	&damon_sysfs_watermarks_mid_attr.attr,
-	&damon_sysfs_watermarks_low_attr.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(damon_sysfs_watermarks);
-
-static struct kobj_type damon_sysfs_watermarks_ktype = {
-	.release = damon_sysfs_watermarks_release,
-	.sysfs_ops = &kobj_sysfs_ops,
-	.default_groups = damon_sysfs_watermarks_groups,
-};
-
-/*
- * scheme/weights directory
- */
-
-struct damon_sysfs_weights {
-	struct kobject kobj;
-	unsigned int sz;
-	unsigned int nr_accesses;
-	unsigned int age;
-};
-
-static struct damon_sysfs_weights *damon_sysfs_weights_alloc(unsigned int sz,
-		unsigned int nr_accesses, unsigned int age)
-{
-	struct damon_sysfs_weights *weights = kmalloc(sizeof(*weights),
-			GFP_KERNEL);
-
-	if (!weights)
-		return NULL;
-	weights->kobj = (struct kobject){};
-	weights->sz = sz;
-	weights->nr_accesses = nr_accesses;
-	weights->age = age;
-	return weights;
-}
-
-static ssize_t sz_permil_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_weights *weights = container_of(kobj,
-			struct damon_sysfs_weights, kobj);
-
-	return sysfs_emit(buf, "%u\n", weights->sz);
-}
-
-static ssize_t sz_permil_store(struct kobject *kobj,
-		struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	struct damon_sysfs_weights *weights = container_of(kobj,
-			struct damon_sysfs_weights, kobj);
-	int err = kstrtouint(buf, 0, &weights->sz);
-
-	return err ? err : count;
-}
-
-static ssize_t nr_accesses_permil_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_weights *weights = container_of(kobj,
-			struct damon_sysfs_weights, kobj);
-
-	return sysfs_emit(buf, "%u\n", weights->nr_accesses);
-}
-
-static ssize_t nr_accesses_permil_store(struct kobject *kobj,
-		struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	struct damon_sysfs_weights *weights = container_of(kobj,
-			struct damon_sysfs_weights, kobj);
-	int err = kstrtouint(buf, 0, &weights->nr_accesses);
-
-	return err ? err : count;
-}
-
-static ssize_t age_permil_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_weights *weights = container_of(kobj,
-			struct damon_sysfs_weights, kobj);
-
-	return sysfs_emit(buf, "%u\n", weights->age);
-}
-
-static ssize_t age_permil_store(struct kobject *kobj,
-		struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	struct damon_sysfs_weights *weights = container_of(kobj,
-			struct damon_sysfs_weights, kobj);
-	int err = kstrtouint(buf, 0, &weights->age);
-
-	return err ? err : count;
-}
-
-static void damon_sysfs_weights_release(struct kobject *kobj)
-{
-	kfree(container_of(kobj, struct damon_sysfs_weights, kobj));
-}
-
-static struct kobj_attribute damon_sysfs_weights_sz_attr =
-		__ATTR_RW_MODE(sz_permil, 0600);
-
-static struct kobj_attribute damon_sysfs_weights_nr_accesses_attr =
-		__ATTR_RW_MODE(nr_accesses_permil, 0600);
-
-static struct kobj_attribute damon_sysfs_weights_age_attr =
-		__ATTR_RW_MODE(age_permil, 0600);
-
-static struct attribute *damon_sysfs_weights_attrs[] = {
-	&damon_sysfs_weights_sz_attr.attr,
-	&damon_sysfs_weights_nr_accesses_attr.attr,
-	&damon_sysfs_weights_age_attr.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(damon_sysfs_weights);
-
-static struct kobj_type damon_sysfs_weights_ktype = {
-	.release = damon_sysfs_weights_release,
-	.sysfs_ops = &kobj_sysfs_ops,
-	.default_groups = damon_sysfs_weights_groups,
-};
-
-/*
- * quotas directory
- */
-
-struct damon_sysfs_quotas {
-	struct kobject kobj;
-	struct damon_sysfs_weights *weights;
-	unsigned long ms;
-	unsigned long sz;
-	unsigned long reset_interval_ms;
-};
-
-static struct damon_sysfs_quotas *damon_sysfs_quotas_alloc(void)
-{
-	return kzalloc(sizeof(struct damon_sysfs_quotas), GFP_KERNEL);
-}
-
-static int damon_sysfs_quotas_add_dirs(struct damon_sysfs_quotas *quotas)
-{
-	struct damon_sysfs_weights *weights;
-	int err;
-
-	weights = damon_sysfs_weights_alloc(0, 0, 0);
-	if (!weights)
-		return -ENOMEM;
-
-	err = kobject_init_and_add(&weights->kobj, &damon_sysfs_weights_ktype,
-			&quotas->kobj, "weights");
-	if (err)
-		kobject_put(&weights->kobj);
-	else
-		quotas->weights = weights;
-	return err;
-}
-
-static void damon_sysfs_quotas_rm_dirs(struct damon_sysfs_quotas *quotas)
-{
-	kobject_put(&quotas->weights->kobj);
-}
-
-static ssize_t ms_show(struct kobject *kobj, struct kobj_attribute *attr,
-		char *buf)
-{
-	struct damon_sysfs_quotas *quotas = container_of(kobj,
-			struct damon_sysfs_quotas, kobj);
-
-	return sysfs_emit(buf, "%lu\n", quotas->ms);
-}
-
-static ssize_t ms_store(struct kobject *kobj, struct kobj_attribute *attr,
-		const char *buf, size_t count)
-{
-	struct damon_sysfs_quotas *quotas = container_of(kobj,
-			struct damon_sysfs_quotas, kobj);
-	int err = kstrtoul(buf, 0, &quotas->ms);
-
-	if (err)
-		return -EINVAL;
-	return count;
-}
-
-static ssize_t bytes_show(struct kobject *kobj, struct kobj_attribute *attr,
-		char *buf)
-{
-	struct damon_sysfs_quotas *quotas = container_of(kobj,
-			struct damon_sysfs_quotas, kobj);
-
-	return sysfs_emit(buf, "%lu\n", quotas->sz);
-}
-
-static ssize_t bytes_store(struct kobject *kobj,
-		struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	struct damon_sysfs_quotas *quotas = container_of(kobj,
-			struct damon_sysfs_quotas, kobj);
-	int err = kstrtoul(buf, 0, &quotas->sz);
-
-	if (err)
-		return -EINVAL;
-	return count;
-}
-
-static ssize_t reset_interval_ms_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_quotas *quotas = container_of(kobj,
-			struct damon_sysfs_quotas, kobj);
-
-	return sysfs_emit(buf, "%lu\n", quotas->reset_interval_ms);
-}
-
-static ssize_t reset_interval_ms_store(struct kobject *kobj,
-		struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	struct damon_sysfs_quotas *quotas = container_of(kobj,
-			struct damon_sysfs_quotas, kobj);
-	int err = kstrtoul(buf, 0, &quotas->reset_interval_ms);
-
-	if (err)
-		return -EINVAL;
-	return count;
-}
-
-static void damon_sysfs_quotas_release(struct kobject *kobj)
-{
-	kfree(container_of(kobj, struct damon_sysfs_quotas, kobj));
-}
-
-static struct kobj_attribute damon_sysfs_quotas_ms_attr =
-		__ATTR_RW_MODE(ms, 0600);
-
-static struct kobj_attribute damon_sysfs_quotas_sz_attr =
-		__ATTR_RW_MODE(bytes, 0600);
-
-static struct kobj_attribute damon_sysfs_quotas_reset_interval_ms_attr =
-		__ATTR_RW_MODE(reset_interval_ms, 0600);
-
-static struct attribute *damon_sysfs_quotas_attrs[] = {
-	&damon_sysfs_quotas_ms_attr.attr,
-	&damon_sysfs_quotas_sz_attr.attr,
-	&damon_sysfs_quotas_reset_interval_ms_attr.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(damon_sysfs_quotas);
-
-static struct kobj_type damon_sysfs_quotas_ktype = {
-	.release = damon_sysfs_quotas_release,
-	.sysfs_ops = &kobj_sysfs_ops,
-	.default_groups = damon_sysfs_quotas_groups,
-};
-
-/*
- * access_pattern directory
- */
-
-struct damon_sysfs_access_pattern {
-	struct kobject kobj;
-	struct damon_sysfs_ul_range *sz;
-	struct damon_sysfs_ul_range *nr_accesses;
-	struct damon_sysfs_ul_range *age;
-};
-
-static
-struct damon_sysfs_access_pattern *damon_sysfs_access_pattern_alloc(void)
-{
-	struct damon_sysfs_access_pattern *access_pattern =
-		kmalloc(sizeof(*access_pattern), GFP_KERNEL);
-
-	if (!access_pattern)
-		return NULL;
-	access_pattern->kobj = (struct kobject){};
-	return access_pattern;
-}
-
-static int damon_sysfs_access_pattern_add_range_dir(
-		struct damon_sysfs_access_pattern *access_pattern,
-		struct damon_sysfs_ul_range **range_dir_ptr,
-		char *name)
-{
-	struct damon_sysfs_ul_range *range = damon_sysfs_ul_range_alloc(0, 0);
-	int err;
-
-	if (!range)
-		return -ENOMEM;
-	err = kobject_init_and_add(&range->kobj, &damon_sysfs_ul_range_ktype,
-			&access_pattern->kobj, name);
-	if (err)
-		kobject_put(&range->kobj);
-	else
-		*range_dir_ptr = range;
-	return err;
-}
-
-static int damon_sysfs_access_pattern_add_dirs(
-		struct damon_sysfs_access_pattern *access_pattern)
-{
-	int err;
-
-	err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
-			&access_pattern->sz, "sz");
-	if (err)
-		goto put_sz_out;
-
-	err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
-			&access_pattern->nr_accesses, "nr_accesses");
-	if (err)
-		goto put_nr_accesses_sz_out;
-
-	err = damon_sysfs_access_pattern_add_range_dir(access_pattern,
-			&access_pattern->age, "age");
-	if (err)
-		goto put_age_nr_accesses_sz_out;
-	return 0;
-
-put_age_nr_accesses_sz_out:
-	kobject_put(&access_pattern->age->kobj);
-	access_pattern->age = NULL;
-put_nr_accesses_sz_out:
-	kobject_put(&access_pattern->nr_accesses->kobj);
-	access_pattern->nr_accesses = NULL;
-put_sz_out:
-	kobject_put(&access_pattern->sz->kobj);
-	access_pattern->sz = NULL;
-	return err;
-}
-
-static void damon_sysfs_access_pattern_rm_dirs(
-		struct damon_sysfs_access_pattern *access_pattern)
-{
-	kobject_put(&access_pattern->sz->kobj);
-	kobject_put(&access_pattern->nr_accesses->kobj);
-	kobject_put(&access_pattern->age->kobj);
-}
-
-static void damon_sysfs_access_pattern_release(struct kobject *kobj)
-{
-	kfree(container_of(kobj, struct damon_sysfs_access_pattern, kobj));
-}
-
-static struct attribute *damon_sysfs_access_pattern_attrs[] = {
-	NULL,
-};
-ATTRIBUTE_GROUPS(damon_sysfs_access_pattern);
-
-static struct kobj_type damon_sysfs_access_pattern_ktype = {
-	.release = damon_sysfs_access_pattern_release,
-	.sysfs_ops = &kobj_sysfs_ops,
-	.default_groups = damon_sysfs_access_pattern_groups,
-};
-
-/*
- * scheme directory
- */
-
-struct damon_sysfs_scheme {
-	struct kobject kobj;
-	enum damos_action action;
-	struct damon_sysfs_access_pattern *access_pattern;
-	struct damon_sysfs_quotas *quotas;
-	struct damon_sysfs_watermarks *watermarks;
-	struct damon_sysfs_stats *stats;
-};
-
-/* This should match with enum damos_action */
-static const char * const damon_sysfs_damos_action_strs[] = {
-	"willneed",
-	"cold",
-	"pageout",
-	"hugepage",
-	"nohugepage",
-	"lru_prio",
-	"lru_deprio",
-	"stat",
-};
-
-static struct damon_sysfs_scheme *damon_sysfs_scheme_alloc(
-		enum damos_action action)
-{
-	struct damon_sysfs_scheme *scheme = kmalloc(sizeof(*scheme),
-				GFP_KERNEL);
-
-	if (!scheme)
-		return NULL;
-	scheme->kobj = (struct kobject){};
-	scheme->action = action;
-	return scheme;
-}
-
-static int damon_sysfs_scheme_set_access_pattern(
-		struct damon_sysfs_scheme *scheme)
-{
-	struct damon_sysfs_access_pattern *access_pattern;
-	int err;
-
-	access_pattern = damon_sysfs_access_pattern_alloc();
-	if (!access_pattern)
-		return -ENOMEM;
-	err = kobject_init_and_add(&access_pattern->kobj,
-			&damon_sysfs_access_pattern_ktype, &scheme->kobj,
-			"access_pattern");
-	if (err)
-		goto out;
-	err = damon_sysfs_access_pattern_add_dirs(access_pattern);
-	if (err)
-		goto out;
-	scheme->access_pattern = access_pattern;
-	return 0;
-
-out:
-	kobject_put(&access_pattern->kobj);
-	return err;
-}
-
-static int damon_sysfs_scheme_set_quotas(struct damon_sysfs_scheme *scheme)
-{
-	struct damon_sysfs_quotas *quotas = damon_sysfs_quotas_alloc();
-	int err;
-
-	if (!quotas)
-		return -ENOMEM;
-	err = kobject_init_and_add(&quotas->kobj, &damon_sysfs_quotas_ktype,
-			&scheme->kobj, "quotas");
-	if (err)
-		goto out;
-	err = damon_sysfs_quotas_add_dirs(quotas);
-	if (err)
-		goto out;
-	scheme->quotas = quotas;
-	return 0;
-
-out:
-	kobject_put(&quotas->kobj);
-	return err;
-}
-
-static int damon_sysfs_scheme_set_watermarks(struct damon_sysfs_scheme *scheme)
-{
-	struct damon_sysfs_watermarks *watermarks =
-		damon_sysfs_watermarks_alloc(DAMOS_WMARK_NONE, 0, 0, 0, 0);
-	int err;
-
-	if (!watermarks)
-		return -ENOMEM;
-	err = kobject_init_and_add(&watermarks->kobj,
-			&damon_sysfs_watermarks_ktype, &scheme->kobj,
-			"watermarks");
-	if (err)
-		kobject_put(&watermarks->kobj);
-	else
-		scheme->watermarks = watermarks;
-	return err;
-}
-
-static int damon_sysfs_scheme_set_stats(struct damon_sysfs_scheme *scheme)
-{
-	struct damon_sysfs_stats *stats = damon_sysfs_stats_alloc();
-	int err;
-
-	if (!stats)
-		return -ENOMEM;
-	err = kobject_init_and_add(&stats->kobj, &damon_sysfs_stats_ktype,
-			&scheme->kobj, "stats");
-	if (err)
-		kobject_put(&stats->kobj);
-	else
-		scheme->stats = stats;
-	return err;
-}
-
-static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
-{
-	int err;
-
-	err = damon_sysfs_scheme_set_access_pattern(scheme);
-	if (err)
-		return err;
-	err = damon_sysfs_scheme_set_quotas(scheme);
-	if (err)
-		goto put_access_pattern_out;
-	err = damon_sysfs_scheme_set_watermarks(scheme);
-	if (err)
-		goto put_quotas_access_pattern_out;
-	err = damon_sysfs_scheme_set_stats(scheme);
-	if (err)
-		goto put_watermarks_quotas_access_pattern_out;
-	return 0;
-
-put_watermarks_quotas_access_pattern_out:
-	kobject_put(&scheme->watermarks->kobj);
-	scheme->watermarks = NULL;
-put_quotas_access_pattern_out:
-	kobject_put(&scheme->quotas->kobj);
-	scheme->quotas = NULL;
-put_access_pattern_out:
-	kobject_put(&scheme->access_pattern->kobj);
-	scheme->access_pattern = NULL;
-	return err;
-}
-
-static void damon_sysfs_scheme_rm_dirs(struct damon_sysfs_scheme *scheme)
-{
-	damon_sysfs_access_pattern_rm_dirs(scheme->access_pattern);
-	kobject_put(&scheme->access_pattern->kobj);
-	damon_sysfs_quotas_rm_dirs(scheme->quotas);
-	kobject_put(&scheme->quotas->kobj);
-	kobject_put(&scheme->watermarks->kobj);
-	kobject_put(&scheme->stats->kobj);
-}
-
-static ssize_t action_show(struct kobject *kobj, struct kobj_attribute *attr,
-		char *buf)
-{
-	struct damon_sysfs_scheme *scheme = container_of(kobj,
-			struct damon_sysfs_scheme, kobj);
-
-	return sysfs_emit(buf, "%s\n",
-			damon_sysfs_damos_action_strs[scheme->action]);
-}
-
-static ssize_t action_store(struct kobject *kobj, struct kobj_attribute *attr,
-		const char *buf, size_t count)
-{
-	struct damon_sysfs_scheme *scheme = container_of(kobj,
-			struct damon_sysfs_scheme, kobj);
-	enum damos_action action;
-
-	for (action = 0; action < NR_DAMOS_ACTIONS; action++) {
-		if (sysfs_streq(buf, damon_sysfs_damos_action_strs[action])) {
-			scheme->action = action;
-			return count;
-		}
-	}
-	return -EINVAL;
-}
-
-static void damon_sysfs_scheme_release(struct kobject *kobj)
-{
-	kfree(container_of(kobj, struct damon_sysfs_scheme, kobj));
-}
-
-static struct kobj_attribute damon_sysfs_scheme_action_attr =
-		__ATTR_RW_MODE(action, 0600);
-
-static struct attribute *damon_sysfs_scheme_attrs[] = {
-	&damon_sysfs_scheme_action_attr.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(damon_sysfs_scheme);
-
-static struct kobj_type damon_sysfs_scheme_ktype = {
-	.release = damon_sysfs_scheme_release,
-	.sysfs_ops = &kobj_sysfs_ops,
-	.default_groups = damon_sysfs_scheme_groups,
-};
-
-/*
- * schemes directory
- */
-
-struct damon_sysfs_schemes {
-	struct kobject kobj;
-	struct damon_sysfs_scheme **schemes_arr;
-	int nr;
-};
-
-static struct damon_sysfs_schemes *damon_sysfs_schemes_alloc(void)
-{
-	return kzalloc(sizeof(struct damon_sysfs_schemes), GFP_KERNEL);
-}
-
-static void damon_sysfs_schemes_rm_dirs(struct damon_sysfs_schemes *schemes)
-{
-	struct damon_sysfs_scheme **schemes_arr = schemes->schemes_arr;
-	int i;
-
-	for (i = 0; i < schemes->nr; i++) {
-		damon_sysfs_scheme_rm_dirs(schemes_arr[i]);
-		kobject_put(&schemes_arr[i]->kobj);
-	}
-	schemes->nr = 0;
-	kfree(schemes_arr);
-	schemes->schemes_arr = NULL;
-}
-
-static int damon_sysfs_schemes_add_dirs(struct damon_sysfs_schemes *schemes,
-		int nr_schemes)
-{
-	struct damon_sysfs_scheme **schemes_arr, *scheme;
-	int err, i;
-
-	damon_sysfs_schemes_rm_dirs(schemes);
-	if (!nr_schemes)
-		return 0;
-
-	schemes_arr = kmalloc_array(nr_schemes, sizeof(*schemes_arr),
-			GFP_KERNEL | __GFP_NOWARN);
-	if (!schemes_arr)
-		return -ENOMEM;
-	schemes->schemes_arr = schemes_arr;
-
-	for (i = 0; i < nr_schemes; i++) {
-		scheme = damon_sysfs_scheme_alloc(DAMOS_STAT);
-		if (!scheme) {
-			damon_sysfs_schemes_rm_dirs(schemes);
-			return -ENOMEM;
-		}
-
-		err = kobject_init_and_add(&scheme->kobj,
-				&damon_sysfs_scheme_ktype, &schemes->kobj,
-				"%d", i);
-		if (err)
-			goto out;
-		err = damon_sysfs_scheme_add_dirs(scheme);
-		if (err)
-			goto out;
-
-		schemes_arr[i] = scheme;
-		schemes->nr++;
-	}
-	return 0;
-
-out:
-	damon_sysfs_schemes_rm_dirs(schemes);
-	kobject_put(&scheme->kobj);
-	return err;
-}
-
-static ssize_t nr_schemes_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
-{
-	struct damon_sysfs_schemes *schemes = container_of(kobj,
-			struct damon_sysfs_schemes, kobj);
-
-	return sysfs_emit(buf, "%d\n", schemes->nr);
-}
-
-static ssize_t nr_schemes_store(struct kobject *kobj,
-		struct kobj_attribute *attr, const char *buf, size_t count)
-{
-	struct damon_sysfs_schemes *schemes;
-	int nr, err = kstrtoint(buf, 0, &nr);
-
-	if (err)
-		return err;
-	if (nr < 0)
-		return -EINVAL;
-
-	schemes = container_of(kobj, struct damon_sysfs_schemes, kobj);
-
-	if (!mutex_trylock(&damon_sysfs_lock))
-		return -EBUSY;
-	err = damon_sysfs_schemes_add_dirs(schemes, nr);
-	mutex_unlock(&damon_sysfs_lock);
-	if (err)
-		return err;
-	return count;
-}
-
-static void damon_sysfs_schemes_release(struct kobject *kobj)
-{
-	kfree(container_of(kobj, struct damon_sysfs_schemes, kobj));
-}
-
-static struct kobj_attribute damon_sysfs_schemes_nr_attr =
-		__ATTR_RW_MODE(nr_schemes, 0600);
-
-static struct attribute *damon_sysfs_schemes_attrs[] = {
-	&damon_sysfs_schemes_nr_attr.attr,
-	NULL,
-};
-ATTRIBUTE_GROUPS(damon_sysfs_schemes);
-
-static struct kobj_type damon_sysfs_schemes_ktype = {
-	.release = damon_sysfs_schemes_release,
-	.sysfs_ops = &kobj_sysfs_ops,
-	.default_groups = damon_sysfs_schemes_groups,
-};
-
 /*
  * init region directory
  */
@@ -2133,62 +1190,6 @@ static int damon_sysfs_set_targets(struct damon_ctx *ctx,
 	return 0;
 }
 
-static struct damos *damon_sysfs_mk_scheme(
-		struct damon_sysfs_scheme *sysfs_scheme)
-{
-	struct damon_sysfs_access_pattern *access_pattern =
-		sysfs_scheme->access_pattern;
-	struct damon_sysfs_quotas *sysfs_quotas = sysfs_scheme->quotas;
-	struct damon_sysfs_weights *sysfs_weights = sysfs_quotas->weights;
-	struct damon_sysfs_watermarks *sysfs_wmarks = sysfs_scheme->watermarks;
-
-	struct damos_access_pattern pattern = {
-		.min_sz_region = access_pattern->sz->min,
-		.max_sz_region = access_pattern->sz->max,
-		.min_nr_accesses = access_pattern->nr_accesses->min,
-		.max_nr_accesses = access_pattern->nr_accesses->max,
-		.min_age_region = access_pattern->age->min,
-		.max_age_region = access_pattern->age->max,
-	};
-	struct damos_quota quota = {
-		.ms = sysfs_quotas->ms,
-		.sz = sysfs_quotas->sz,
-		.reset_interval = sysfs_quotas->reset_interval_ms,
-		.weight_sz = sysfs_weights->sz,
-		.weight_nr_accesses = sysfs_weights->nr_accesses,
-		.weight_age = sysfs_weights->age,
-	};
-	struct damos_watermarks wmarks = {
-		.metric = sysfs_wmarks->metric,
-		.interval = sysfs_wmarks->interval_us,
-		.high = sysfs_wmarks->high,
-		.mid = sysfs_wmarks->mid,
-		.low = sysfs_wmarks->low,
-	};
-
-	return damon_new_scheme(&pattern, sysfs_scheme->action, &quota,
-			&wmarks);
-}
-
-static int damon_sysfs_set_schemes(struct damon_ctx *ctx,
-		struct damon_sysfs_schemes *sysfs_schemes)
-{
-	int i;
-
-	for (i = 0; i < sysfs_schemes->nr; i++) {
-		struct damos *scheme, *next;
-
-		scheme = damon_sysfs_mk_scheme(sysfs_schemes->schemes_arr[i]);
-		if (!scheme) {
-			damon_for_each_scheme_safe(scheme, next, ctx)
-				damon_destroy_scheme(scheme);
-			return -ENOMEM;
-		}
-		damon_add_scheme(ctx, scheme);
-	}
-	return 0;
-}
-
 static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
 {
 	struct damon_target *t, *next;
@@ -2204,25 +1205,6 @@ static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
 	mutex_unlock(&ctx->kdamond_lock);
 }
 
-static void damon_sysfs_schemes_update_stats(
-		struct damon_sysfs_schemes *sysfs_schemes,
-		struct damon_ctx *ctx)
-{
-	struct damos *scheme;
-	int schemes_idx = 0;
-
-	damon_for_each_scheme(scheme, ctx) {
-		struct damon_sysfs_stats *sysfs_stats;
-
-		sysfs_stats = sysfs_schemes->schemes_arr[schemes_idx++]->stats;
-		sysfs_stats->nr_tried = scheme->stat.nr_tried;
-		sysfs_stats->sz_tried = scheme->stat.sz_tried;
-		sysfs_stats->nr_applied = scheme->stat.nr_applied;
-		sysfs_stats->sz_applied = scheme->stat.sz_applied;
-		sysfs_stats->qt_exceeds = scheme->stat.qt_exceeds;
-	}
-}
-
 /*
  * damon_sysfs_upd_schemes_stats() - Update schemes stats sysfs files.
  * @kdamond:	The kobject wrapper that associated to the kdamond thread.
-- 
2.25.1

[RFC PATCH 13/18] mm/damon/sysfs-schemes: implement schemes/tried_regions directory

[SeongJae Park]

For deep level investigation of DAMON and efficient query-like
monitoring results reading, DAMON kernel API (include/linux/damon.h)
users can use 'before_damos_apply' DAMON callback.  However, DAMON sysfs
interface users don't have such option.  Add a directory, namely
'tried_regions', under each scheme directory to use it as the interface
for the purpose.  That is, users will be able to signal DAMON to fill
the directory with the regions that corresponding scheme has tried to be
applied.  By setting the access pattern of the scheme, users could do the
efficient query-like monitoring.  Note that this commit is implementing
only the directory but the data filling.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 57 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 7ea4bcce90cb..f9714ac62565 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -9,6 +9,36 @@
 
 #include "sysfs-common.h"
 
+/*
+ * scheme regions directory
+ */
+
+struct damon_sysfs_scheme_regions {
+	struct kobject kobj;
+};
+
+static struct damon_sysfs_scheme_regions *
+damon_sysfs_scheme_regions_alloc(void)
+{
+	return kzalloc(sizeof(struct damon_sysfs_scheme_regions), GFP_KERNEL);
+}
+
+static void damon_sysfs_scheme_regions_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_scheme_regions, kobj));
+}
+
+static struct attribute *damon_sysfs_scheme_regions_attrs[] = {
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_scheme_regions);
+
+static struct kobj_type damon_sysfs_scheme_regions_ktype = {
+	.release = damon_sysfs_scheme_regions_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_scheme_regions_groups,
+};
+
 /*
  * schemes/stats directory
  */
@@ -635,6 +665,7 @@ struct damon_sysfs_scheme {
 	struct damon_sysfs_quotas *quotas;
 	struct damon_sysfs_watermarks *watermarks;
 	struct damon_sysfs_stats *stats;
+	struct damon_sysfs_scheme_regions *tried_regions;
 };
 
 /* This should match with enum damos_action */
@@ -743,6 +774,25 @@ static int damon_sysfs_scheme_set_stats(struct damon_sysfs_scheme *scheme)
 	return err;
 }
 
+static int damon_sysfs_scheme_set_tried_regions(
+		struct damon_sysfs_scheme *scheme)
+{
+	struct damon_sysfs_scheme_regions *tried_regions =
+		damon_sysfs_scheme_regions_alloc();
+	int err;
+
+	if (!tried_regions)
+		return -ENOMEM;
+	err = kobject_init_and_add(&tried_regions->kobj,
+			&damon_sysfs_scheme_regions_ktype, &scheme->kobj,
+			"tried_regions");
+	if (err)
+		kobject_put(&tried_regions->kobj);
+	else
+		scheme->tried_regions = tried_regions;
+	return err;
+}
+
 static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
 {
 	int err;
@@ -759,8 +809,14 @@ static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
 	err = damon_sysfs_scheme_set_stats(scheme);
 	if (err)
 		goto put_watermarks_quotas_access_pattern_out;
+	err = damon_sysfs_scheme_set_tried_regions(scheme);
+	if (err)
+		goto put_tried_regions_out;
 	return 0;
 
+put_tried_regions_out:
+	kobject_put(&scheme->tried_regions->kobj);
+	scheme->tried_regions = NULL;
 put_watermarks_quotas_access_pattern_out:
 	kobject_put(&scheme->watermarks->kobj);
 	scheme->watermarks = NULL;
@@ -781,6 +837,7 @@ static void damon_sysfs_scheme_rm_dirs(struct damon_sysfs_scheme *scheme)
 	kobject_put(&scheme->quotas->kobj);
 	kobject_put(&scheme->watermarks->kobj);
 	kobject_put(&scheme->stats->kobj);
+	kobject_put(&scheme->tried_regions->kobj);
 }
 
 static ssize_t action_show(struct kobject *kobj, struct kobj_attribute *attr,
-- 
2.25.1

[RFC PATCH 14/18] mm/damon/sysfs-schemes: implement scheme region directory

[SeongJae Park]

Implement code for each region directory under 'tried_regions' directory
of each scheme directory.  This directory will provide the address
range, the monitored access frequency ('nr_accesses'), and the age of
each DAMON region that corresponding DAMON-based operation scheme has
tried to be applied.  Note that this commit doesn't implement the code
for filling the data but the sysfs directory.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-schemes.c | 123 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 122 insertions(+), 1 deletion(-)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index f9714ac62565..1a8ab6341bf1 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -9,18 +9,138 @@
 
 #include "sysfs-common.h"
 
+/*
+ * scheme region directory
+ */
+
+struct damon_sysfs_scheme_region {
+	struct kobject kobj;
+	struct damon_addr_range ar;
+	unsigned int nr_accesses;
+	unsigned int age;
+	struct list_head list;
+};
+
+static struct damon_sysfs_scheme_region *damon_sysfs_scheme_region_alloc(
+		struct damon_region *region)
+{
+	struct damon_sysfs_scheme_region *sysfs_region = kmalloc(
+			sizeof(*sysfs_region), GFP_KERNEL);
+
+	if (!sysfs_region)
+		return NULL;
+	sysfs_region->kobj = (struct kobject){};
+	sysfs_region->ar = region->ar;
+	sysfs_region->nr_accesses = region->nr_accesses;
+	sysfs_region->age = region->age;
+	INIT_LIST_HEAD(&sysfs_region->list);
+	return sysfs_region;
+}
+
+static ssize_t start_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_scheme_region *region = container_of(kobj,
+			struct damon_sysfs_scheme_region, kobj);
+
+	return sysfs_emit(buf, "%lu\n", region->ar.start);
+}
+
+static ssize_t end_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_scheme_region *region = container_of(kobj,
+			struct damon_sysfs_scheme_region, kobj);
+
+	return sysfs_emit(buf, "%lu\n", region->ar.end);
+}
+
+static ssize_t nr_accesses_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_scheme_region *region = container_of(kobj,
+			struct damon_sysfs_scheme_region, kobj);
+
+	return sysfs_emit(buf, "%u\n", region->nr_accesses);
+}
+
+static ssize_t age_show(struct kobject *kobj, struct kobj_attribute *attr,
+		char *buf)
+{
+	struct damon_sysfs_scheme_region *region = container_of(kobj,
+			struct damon_sysfs_scheme_region, kobj);
+
+	return sysfs_emit(buf, "%u\n", region->age);
+}
+
+static void damon_sysfs_scheme_region_release(struct kobject *kobj)
+{
+	struct damon_sysfs_scheme_region *region = container_of(kobj,
+			struct damon_sysfs_scheme_region, kobj);
+
+	list_del(&region->list);
+	kfree(region);
+}
+
+static struct kobj_attribute damon_sysfs_scheme_region_start_attr =
+		__ATTR_RO_MODE(start, 0400);
+
+static struct kobj_attribute damon_sysfs_scheme_region_end_attr =
+		__ATTR_RO_MODE(end, 0400);
+
+static struct kobj_attribute damon_sysfs_scheme_region_nr_accesses_attr =
+		__ATTR_RO_MODE(nr_accesses, 0400);
+
+static struct kobj_attribute damon_sysfs_scheme_region_age_attr =
+		__ATTR_RO_MODE(age, 0400);
+
+static struct attribute *damon_sysfs_scheme_region_attrs[] = {
+	&damon_sysfs_scheme_region_start_attr.attr,
+	&damon_sysfs_scheme_region_end_attr.attr,
+	&damon_sysfs_scheme_region_nr_accesses_attr.attr,
+	&damon_sysfs_scheme_region_age_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_scheme_region);
+
+static struct kobj_type damon_sysfs_scheme_region_ktype = {
+	.release = damon_sysfs_scheme_region_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_scheme_region_groups,
+};
+
 /*
  * scheme regions directory
  */
 
 struct damon_sysfs_scheme_regions {
 	struct kobject kobj;
+	struct list_head regions_list;
+	int nr_regions;
 };
 
 static struct damon_sysfs_scheme_regions *
 damon_sysfs_scheme_regions_alloc(void)
 {
-	return kzalloc(sizeof(struct damon_sysfs_scheme_regions), GFP_KERNEL);
+	struct damon_sysfs_scheme_regions *regions = kmalloc(sizeof(*regions),
+			GFP_KERNEL);
+
+	regions->kobj = (struct kobject){};
+	INIT_LIST_HEAD(&regions->regions_list);
+	regions->nr_regions = 0;
+	return regions;
+}
+
+static void damon_sysfs_scheme_regions_rm_dirs(
+		struct damon_sysfs_scheme_regions *regions)
+{
+	struct damon_sysfs_scheme_region *r, *next;
+
+	list_for_each_entry_safe(r, next, &regions->regions_list, list) {
+		/* release function deletes it from the list */
+		kobject_put(&r->kobj);
+		regions->nr_regions--;
+	}
 }
 
 static void damon_sysfs_scheme_regions_release(struct kobject *kobj)
@@ -837,6 +957,7 @@ static void damon_sysfs_scheme_rm_dirs(struct damon_sysfs_scheme *scheme)
 	kobject_put(&scheme->quotas->kobj);
 	kobject_put(&scheme->watermarks->kobj);
 	kobject_put(&scheme->stats->kobj);
+	damon_sysfs_scheme_regions_rm_dirs(scheme->tried_regions);
 	kobject_put(&scheme->tried_regions->kobj);
 }
 
-- 
2.25.1

[RFC PATCH 15/18] mm/damon/sysfs: implement DAMOS-tried regions update command

[SeongJae Park]

Implement filling of the data for 'tried_regions' directory of
DAMON-based operation schemes for specific kdamond.  With this commit,
DAMON sysfs interface users can write a special keyword,
'update_schemes_regions' to the 'state' file of the kdamond directory to
signal DAMON to fill the relevant 'tried_regions' directories.  In
detail, once the keyword is written, DAMON sysfs interface will collect
the information using the 'before_damos_apply()' callback for one
aggregation interval and populate scheme region directories with the
values.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-common.h  |  6 ++++
 mm/damon/sysfs-schemes.c | 64 ++++++++++++++++++++++++++++++++++++++++
 mm/damon/sysfs.c         | 54 +++++++++++++++++++++++++++++++--
 3 files changed, 122 insertions(+), 2 deletions(-)

diff --git a/mm/damon/sysfs-common.h b/mm/damon/sysfs-common.h
index 4626b2784404..634a6e7fca78 100644
--- a/mm/damon/sysfs-common.h
+++ b/mm/damon/sysfs-common.h
@@ -44,3 +44,9 @@ int damon_sysfs_set_schemes(struct damon_ctx *ctx,
 void damon_sysfs_schemes_update_stats(
 		struct damon_sysfs_schemes *sysfs_schemes,
 		struct damon_ctx *ctx);
+
+int damon_sysfs_schemes_update_regions_start(
+		struct damon_sysfs_schemes *sysfs_schemes,
+		struct damon_ctx *ctx);
+
+int damon_sysfs_schemes_update_regions_stop(struct damon_ctx *ctx);
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 1a8ab6341bf1..2cea58e49d8d 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1198,3 +1198,67 @@ void damon_sysfs_schemes_update_stats(
 		sysfs_stats->qt_exceeds = scheme->stat.qt_exceeds;
 	}
 }
+
+/*
+ * damon_sysfs_schemes that need to update its schemes regions dir.  Protected
+ * by damon_sysfs_lock
+ */
+static struct damon_sysfs_schemes *damon_sysfs_schemes_for_damos_callback;
+static int damon_sysfs_schemes_region_idx;
+
+/*
+ * DAMON callback that called before damos apply.  While this callback is
+ * registered, damon_sysfs_lock should be held to ensure the regions
+ * directories exist.
+ */
+static int damon_sysfs_before_damos_apply(struct damon_ctx *ctx,
+		struct damon_target *t, struct damon_region *r,
+		struct damos *s)
+{
+	struct damos *scheme;
+	struct damon_sysfs_scheme_regions *sysfs_regions;
+	struct damon_sysfs_scheme_region *region;
+	struct damon_sysfs_schemes *sysfs_schemes =
+		damon_sysfs_schemes_for_damos_callback;
+	int schemes_idx = 0;
+
+	damon_for_each_scheme(scheme, ctx) {
+		if (scheme == s)
+			break;
+		schemes_idx++;
+	}
+	sysfs_regions = sysfs_schemes->schemes_arr[schemes_idx]->tried_regions;
+	region = damon_sysfs_scheme_region_alloc(r);
+	list_add_tail(&region->list, &sysfs_regions->regions_list);
+	sysfs_regions->nr_regions++;
+	if (kobject_init_and_add(&region->kobj,
+				&damon_sysfs_scheme_region_ktype,
+				&sysfs_regions->kobj, "%d",
+				damon_sysfs_schemes_region_idx++)) {
+		kobject_put(&region->kobj);
+	}
+	return 0;
+}
+
+/* Called from damon_sysfs_cmd_request_callback under damon_sysfs_lock */
+int damon_sysfs_schemes_update_regions_start(
+		struct damon_sysfs_schemes *sysfs_schemes,
+		struct damon_ctx *ctx)
+{
+	damon_sysfs_schemes_for_damos_callback = sysfs_schemes;
+	ctx->callback.before_damos_apply = damon_sysfs_before_damos_apply;
+	return 0;
+}
+
+/*
+ * Called from damon_sysfs_cmd_request_callback under damon_sysfs_lock.  Caller
+ * should unlock damon_sysfs_lock which held before
+ * damon_sysfs_schemes_update_regions_start()
+ */
+int damon_sysfs_schemes_update_regions_stop(struct damon_ctx *ctx)
+{
+	damon_sysfs_schemes_for_damos_callback = NULL;
+	ctx->callback.before_damos_apply = NULL;
+	damon_sysfs_schemes_region_idx = 0;
+	return 0;
+}
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 284daf274b3e..6d26ae6052b6 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -999,6 +999,8 @@ enum damon_sysfs_cmd {
 	 * files.
 	 */
 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS,
+	/* @DAMON_SYSFS_CMD_UPDATE_SCHEMES_REGIONS: Update scheme regions */
+	DAMON_SYSFS_CMD_UPDATE_SCHEMES_REGIONS,
 	/*
 	 * @NR_DAMON_SYSFS_CMDS: Total number of DAMON sysfs commands.
 	 */
@@ -1011,6 +1013,7 @@ static const char * const damon_sysfs_cmd_strs[] = {
 	"off",
 	"commit",
 	"update_schemes_stats",
+	"update_schemes_regions",
 };
 
 /*
@@ -1193,6 +1196,16 @@ static int damon_sysfs_set_targets(struct damon_ctx *ctx,
 static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
 {
 	struct damon_target *t, *next;
+	struct damon_sysfs_kdamond *kdamond;
+
+	/* damon_sysfs_schemes_update_regions_stop() might not yet called */
+	kdamond = damon_sysfs_cmd_request.kdamond;
+	if (kdamond && damon_sysfs_cmd_request.cmd ==
+			DAMON_SYSFS_CMD_UPDATE_SCHEMES_REGIONS &&
+			ctx == kdamond->damon_ctx) {
+		damon_sysfs_schemes_update_regions_stop(ctx);
+		mutex_unlock(&damon_sysfs_lock);
+	}
 
 	if (!damon_target_has_pid(ctx))
 		return;
@@ -1225,6 +1238,27 @@ static int damon_sysfs_upd_schemes_stats(struct damon_sysfs_kdamond *kdamond)
 	return 0;
 }
 
+static int damon_sysfs_upd_schemes_regions_start(
+		struct damon_sysfs_kdamond *kdamond)
+{
+	struct damon_ctx *ctx = kdamond->damon_ctx;
+
+	if (!ctx)
+		return -EINVAL;
+	return damon_sysfs_schemes_update_regions_start(
+			kdamond->contexts->contexts_arr[0]->schemes, ctx);
+}
+
+static int damon_sysfs_upd_schemes_regions_stop(
+		struct damon_sysfs_kdamond *kdamond)
+{
+	struct damon_ctx *ctx = kdamond->damon_ctx;
+
+	if (!ctx)
+		return -EINVAL;
+	return damon_sysfs_schemes_update_regions_stop(ctx);
+}
+
 static inline bool damon_sysfs_kdamond_running(
 		struct damon_sysfs_kdamond *kdamond)
 {
@@ -1277,10 +1311,12 @@ static int damon_sysfs_commit_input(struct damon_sysfs_kdamond *kdamond)
 static int damon_sysfs_cmd_request_callback(struct damon_ctx *c)
 {
 	struct damon_sysfs_kdamond *kdamond;
+	static bool damon_sysfs_schemes_regions_updating;
 	int err = 0;
 
 	/* avoid deadlock due to concurrent state_store('off') */
-	if (!mutex_trylock(&damon_sysfs_lock))
+	if (!damon_sysfs_schemes_regions_updating &&
+			!mutex_trylock(&damon_sysfs_lock))
 		return 0;
 	kdamond = damon_sysfs_cmd_request.kdamond;
 	if (!kdamond || kdamond->damon_ctx != c)
@@ -1292,13 +1328,27 @@ static int damon_sysfs_cmd_request_callback(struct damon_ctx *c)
 	case DAMON_SYSFS_CMD_COMMIT:
 		err = damon_sysfs_commit_input(kdamond);
 		break;
+	case DAMON_SYSFS_CMD_UPDATE_SCHEMES_REGIONS:
+		if (!damon_sysfs_schemes_regions_updating) {
+			err = damon_sysfs_upd_schemes_regions_start(kdamond);
+			if (!err) {
+				damon_sysfs_schemes_regions_updating = true;
+				goto keep_lock_out;
+			}
+		} else {
+			err = damon_sysfs_upd_schemes_regions_stop(kdamond);
+			damon_sysfs_schemes_regions_updating = false;
+		}
+		break;
 	default:
 		break;
 	}
 	/* Mark the request as invalid now. */
 	damon_sysfs_cmd_request.kdamond = NULL;
 out:
-	mutex_unlock(&damon_sysfs_lock);
+	if (!damon_sysfs_schemes_regions_updating)
+		mutex_unlock(&damon_sysfs_lock);
+keep_lock_out:
 	return err;
 }
 
-- 
2.25.1

[RFC PATCH 16/18] mm/damon/sysfs-schemes: implement DAMOS tried regions clear command

[SeongJae Park]

When there are huge number of DAMON regions that specific scheme actions
are tried to be applied, directories and files under 'tried_regions'
scheme directory could waste some memory.  Add another special input
keyword for 'state' file of each kdamond sysfs directory that can be
used for cleanup of the 'tried_regions' sub-directories.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs-common.h  |  4 ++++
 mm/damon/sysfs-schemes.c | 17 +++++++++++++++++
 mm/damon/sysfs.c         | 18 ++++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/mm/damon/sysfs-common.h b/mm/damon/sysfs-common.h
index 634a6e7fca78..604a6cbc3ede 100644
--- a/mm/damon/sysfs-common.h
+++ b/mm/damon/sysfs-common.h
@@ -50,3 +50,7 @@ int damon_sysfs_schemes_update_regions_start(
 		struct damon_ctx *ctx);
 
 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);
diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index 2cea58e49d8d..223de1d06740 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -1262,3 +1262,20 @@ int damon_sysfs_schemes_update_regions_stop(struct damon_ctx *ctx)
 	damon_sysfs_schemes_region_idx = 0;
 	return 0;
 }
+
+int damon_sysfs_schemes_clear_regions(
+		struct damon_sysfs_schemes *sysfs_schemes,
+		struct damon_ctx *ctx)
+{
+	struct damos *scheme;
+	int schemes_idx = 0;
+
+	damon_for_each_scheme(scheme, ctx) {
+		struct damon_sysfs_scheme *sysfs_scheme;
+
+		sysfs_scheme = sysfs_schemes->schemes_arr[schemes_idx++];
+		damon_sysfs_scheme_regions_rm_dirs(
+				sysfs_scheme->tried_regions);
+	}
+	return 0;
+}
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 6d26ae6052b6..acc16473f6fd 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1001,6 +1001,9 @@ enum damon_sysfs_cmd {
 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_STATS,
 	/* @DAMON_SYSFS_CMD_UPDATE_SCHEMES_REGIONS: Update scheme regions */
 	DAMON_SYSFS_CMD_UPDATE_SCHEMES_REGIONS,
+	/* @DAMON_SYSFS_CMD_CLEAR_SCHEMES_REGIONS: Clear scheme regions */
+	DAMON_SYSFS_CMD_CLEAR_SCHEMES_REGIONS,
+
 	/*
 	 * @NR_DAMON_SYSFS_CMDS: Total number of DAMON sysfs commands.
 	 */
@@ -1014,6 +1017,7 @@ static const char * const damon_sysfs_cmd_strs[] = {
 	"commit",
 	"update_schemes_stats",
 	"update_schemes_regions",
+	"clear_schemes_regions",
 };
 
 /*
@@ -1259,6 +1263,17 @@ static int damon_sysfs_upd_schemes_regions_stop(
 	return damon_sysfs_schemes_update_regions_stop(ctx);
 }
 
+static int damon_sysfs_clear_schemes_regions(
+		struct damon_sysfs_kdamond *kdamond)
+{
+	struct damon_ctx *ctx = kdamond->damon_ctx;
+
+	if (!ctx)
+		return -EINVAL;
+	return damon_sysfs_schemes_clear_regions(
+			kdamond->contexts->contexts_arr[0]->schemes, ctx);
+}
+
 static inline bool damon_sysfs_kdamond_running(
 		struct damon_sysfs_kdamond *kdamond)
 {
@@ -1340,6 +1355,9 @@ static int damon_sysfs_cmd_request_callback(struct damon_ctx *c)
 			damon_sysfs_schemes_regions_updating = false;
 		}
 		break;
+	case DAMON_SYSFS_CMD_CLEAR_SCHEMES_REGIONS:
+		err = damon_sysfs_clear_schemes_regions(kdamond);
+		break;
 	default:
 		break;
 	}
-- 
2.25.1

[RFC PATCH 17/18] Docs/admin-guide/mm/damon/usage: document schemes/<s>/tried_regions directory

[SeongJae Park]

Document 'tried_regions' directory in DAMON sysfs interface usage in the
administrator guide.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/usage.rst | 44 ++++++++++++++++++--
 1 file changed, 41 insertions(+), 3 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index b47b0cbbd491..649d63ecf67f 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -88,6 +88,9 @@ comma (","). ::
     │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil
     │ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low
     │ │ │ │ │ │ │ stats/nr_tried,sz_tried,nr_applied,sz_applied,qt_exceeds
+    │ │ │ │ │ │ │ tried_regions/
+    │ │ │ │ │ │ │ │ 0/start,end,nr_accesses,age
+    │ │ │ │ │ │ │ │ ...
     │ │ │ │ │ │ ...
     │ │ │ │ ...
     │ │ ...
@@ -125,7 +128,14 @@ 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>`.
+stats, please refer to :ref:`stats section <sysfs_schemes_stats>`.  Writing
+``update_schemes_regions`` to ``state`` file updates the DAMON-based operation
+scheme action tried regions directory for each DAMON-based operation scheme of
+the kdamond.  Writing ``clear_schemes_regions`` to ``state`` file clears the
+DAMON-based operating scheme action tried regions directory for each
+DAMON-based operation scheme of the kdamond.  For details of the DAMON-based
+operation scheme action tried regions directory, please refer to
+:ref:tried_regions section <sysfs_schemes_tried_regions>`.
 
 If the state is ``on``, reading ``pid`` shows the pid of the kdamond thread.
 
@@ -166,6 +176,8 @@ You can set and get what type of monitoring operations DAMON will use for the
 context by writing one of the keywords listed in ``avail_operations`` file and
 reading from the ``operations`` file.
 
+.. _sysfs_monitoring_attrs:
+
 contexts/<N>/monitoring_attrs/
 ------------------------------
 
@@ -252,8 +264,9 @@ to ``N-1``.  Each directory represents each DAMON-based operation scheme.
 schemes/<N>/
 ------------
 
-In each scheme directory, four directories (``access_pattern``, ``quotas``,
-``watermarks``, and ``stats``) and one file (``action``) exist.
+In each scheme directory, five directories (``access_pattern``, ``quotas``,
+``watermarks``, ``stats``, and ``tried_regions``) and one file (``action``)
+exist.
 
 The ``action`` file is for setting and getting what action you want to apply to
 memory regions having specific access pattern of the interest.  The keywords
@@ -348,6 +361,31 @@ should ask DAMON sysfs interface to updte the content of the files for the
 stats by writing a special keyword, ``update_schemes_stats`` to the relevant
 ``kdamonds/<N>/state`` file.
 
+.. _sysfs_schemes_tried_regions:
+
+schemes/<N>/tried_regions/
+--------------------------
+
+When a special keyword, ``update_schemes_regions``, is written to the relevant
+``kdamonds/<N>/state`` file, DAMON creates directories named integer starting
+from ``0`` under this directory.  Each directory contains files exposing
+detailed information about each of the memory region that the corresponding
+scheme's ``action`` has tried to be applied under this directory, during next
+:ref:`aggregation interval <sysfs_monitoring_attrs>`.  The information includes
+address range, ``nr_accesses``, , and ``age`` of the region.
+
+The directories will be removed when another special keyword,
+``clear_schemes_regions``, is written to the relevant ``kdamonds/<N>/state``
+file.
+
+tried_regions/<N>/
+------------------
+
+In each region directory, you will find four files (``start``, ``end``,
+``nr_accesses``, and ``age``).  Reading the files will show the start and end
+addresses, ``nr_accesses``, and ``age`` of the region that corresponding
+DAMON-based operation scheme ``action`` has tried to be applied.
+
 Example
 ~~~~~~~
 
-- 
2.25.1

[RFC PATCH 18/18] Docs/ABI/damon: document 'schemes/<s>/tried_regions' directory

[SeongJae Park]

Update DAMON ABI document for added 'tried_regions' directory of DAMON
sysfs interface.

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

diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-damon b/Documentation/ABI/testing/sysfs-kernel-mm-damon
index 08b9df323560..7ba95e35b427 100644
--- a/Documentation/ABI/testing/sysfs-kernel-mm-damon
+++ b/Documentation/ABI/testing/sysfs-kernel-mm-damon
@@ -27,6 +27,10 @@ Description:	Writing 'on' or 'off' to this file makes the kdamond starts or
 		makes the kdamond reads the user inputs in the sysfs files
 		except 'state' again.  Writing 'update_schemes_stats' to the
 		file updates contents of schemes stats files of the kdamond.
+		Writing 'update_schemes_regions' to the file updates contents
+		of 'tried_regions' directory of every scheme directory of this
+		kdamond.  Writing 'clear_schemes_regions' to the file removes
+		contents of the 'tried_regions' directory.
 
 What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/pid
 Date:		Mar 2022
@@ -283,3 +287,31 @@ Date:		Mar 2022
 Contact:	SeongJae Park <sj@kernel.org>
 Description:	Reading this file returns the number of the exceed events of
 		the scheme's quotas.
+
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/start
+Date:		Oct 2022
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	Reading this file returns the start address of a memory region
+		that corresponding DAMON-based Operation Scheme's action has
+		tried to be applied.
+
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/end
+Date:		Oct 2022
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	Reading this file returns the end address of a memory region
+		that corresponding DAMON-based Operation Scheme's action has
+		tried to be applied.
+
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/nr_accesses
+Date:		Oct 2022
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	Reading this file returns the 'nr_accesses' of a memory region
+		that corresponding DAMON-based Operation Scheme's action has
+		tried to be applied.
+
+What:		/sys/kernel/mm/damon/admin/kdamonds/<K>/contexts/<C>/schemes/<S>/tried_regions/<R>/age
+Date:		Oct 2022
+Contact:	SeongJae Park <sj@kernel.org>
+Description:	Reading this file returns the 'age' of a memory region that
+		corresponding DAMON-based Operation Scheme's action has tried
+		to be applied.
-- 
2.25.1

Re: [RFC PATCH 00/18] efficiently expose damos action tried regions information

[SeongJae Park]

On Wed, 19 Oct 2022 00:12:59 +0000 SeongJae Park <sj@kernel.org> wrote:

> DAMON users can retrieve the monitoring results via 'after_aggregation'
> callbacks if the user is using the kernel API, or 'damon_aggregated'
> tracepoint if the user is in the user space.  Those are useful if full
> monitoring results are necessary.  However, if the user has interest in
> only some regions having specific access pattern, the interfaces could
> be inefficient.  For example, some DAMOS users might want to know
> exactly what regions were identified as fulfilling the access pattern of
> the scheme, for a debugging or a tuning.
> 
> This patchset implements DAMON kernel API callbacks and sysfs directory
> for efficient exposure of the information.  The new callback will be
> called for each region before specific DAMOS action is gonna tried to be
> applied.  The sysfs directory will be called 'tried_regions' and placed
> under each scheme sysfs directory.  User can write a special keyworkd,
> 'update_schemes_regions' to the 'state' file of a kdamond sysfs
> directory.  Then, DAMON sysfs interface will fill the directory with the
> information of regions that corresponding scheme action was tried to be
> applied for one aggregation interval.
> 
> Patches Sequence
> ----------------
> 
> First five patches (1-5) clean up and refactor code that following patch
> will touch, and the following one (patch 6) implements the DAMON
> callback for DAMON kernel API users.
> 
> Following six patches (7-12) clean up and refactor the sysfs interface
> before the new sysfs directory introduction.  Following two patches (13
> and 14) implement the sysfs directories, and successing two patches (15
> and 16) implement the special keyword for 'state' to fill and clean up
> the directories.
> 
> Finally, two more patches (17 and 18) for the documentation of the usage
> and ABI follow.

I think this patchset is unnecessarily big due to the cleanups and
refactorings.  I added them in this patchset mainly because I found the messy
code while working for the feature.  However, now it looks like it would make
more sense to split them out into separate patchsets.

Just thinking loudly, but any input is welcome.


Thanks,
SJ
[...]