1 files changed, 771 insertions, 54 deletions

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 5b325749fc12..384935ef4e65 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -11,8 +11,10 @@
 #include <linux/delay.h>
 #include <linux/kthread.h>
 #include <linux/mm.h>
+#include <linux/psi.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/string_choices.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/damon.h>
@@ -265,7 +267,7 @@ int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
 }
 
 struct damos_filter *damos_new_filter(enum damos_filter_type type,
-		bool matching)
+		bool matching, bool allow)
 {
 	struct damos_filter *filter;
 
@@ -274,6 +276,7 @@ struct damos_filter *damos_new_filter(enum damos_filter_type type,
 		return NULL;
 	filter->type = type;
 	filter->matching = matching;
+	filter->allow = allow;
 	INIT_LIST_HEAD(&filter->list);
 	return filter;
 }
@@ -299,16 +302,53 @@ void damos_destroy_filter(struct damos_filter *f)
 	damos_free_filter(f);
 }
 
-/* initialize private fields of damos_quota and return the pointer */
-static struct damos_quota *damos_quota_init_priv(struct damos_quota *quota)
+struct damos_quota_goal *damos_new_quota_goal(
+		enum damos_quota_goal_metric metric,
+		unsigned long target_value)
 {
+	struct damos_quota_goal *goal;
+
+	goal = kmalloc(sizeof(*goal), GFP_KERNEL);
+	if (!goal)
+		return NULL;
+	goal->metric = metric;
+	goal->target_value = target_value;
+	INIT_LIST_HEAD(&goal->list);
+	return goal;
+}
+
+void damos_add_quota_goal(struct damos_quota *q, struct damos_quota_goal *g)
+{
+	list_add_tail(&g->list, &q->goals);
+}
+
+static void damos_del_quota_goal(struct damos_quota_goal *g)
+{
+	list_del(&g->list);
+}
+
+static void damos_free_quota_goal(struct damos_quota_goal *g)
+{
+	kfree(g);
+}
+
+void damos_destroy_quota_goal(struct damos_quota_goal *g)
+{
+	damos_del_quota_goal(g);
+	damos_free_quota_goal(g);
+}
+
+/* initialize fields of @quota that normally API users wouldn't set */
+static struct damos_quota *damos_quota_init(struct damos_quota *quota)
+{
+	quota->esz = 0;
 	quota->total_charged_sz = 0;
 	quota->total_charged_ns = 0;
-	quota->esz = 0;
 	quota->charged_sz = 0;
 	quota->charged_from = 0;
 	quota->charge_target_from = NULL;
 	quota->charge_addr_from = 0;
+	quota->esz_bp = 0;
 	return quota;
 }
 
@@ -316,7 +356,8 @@ struct damos *damon_new_scheme(struct damos_access_pattern *pattern,
 			enum damos_action action,
 			unsigned long apply_interval_us,
 			struct damos_quota *quota,
-			struct damos_watermarks *wmarks)
+			struct damos_watermarks *wmarks,
+			int target_nid)
 {
 	struct damos *scheme;
 
@@ -332,15 +373,20 @@ struct damos *damon_new_scheme(struct damos_access_pattern *pattern,
 	 * or damon_attrs are updated.
 	 */
 	scheme->next_apply_sis = 0;
+	scheme->walk_completed = false;
 	INIT_LIST_HEAD(&scheme->filters);
 	scheme->stat = (struct damos_stat){};
 	INIT_LIST_HEAD(&scheme->list);
 
-	scheme->quota = *(damos_quota_init_priv(quota));
+	scheme->quota = *(damos_quota_init(quota));
+	/* quota.goals should be separately set by caller */
+	INIT_LIST_HEAD(&scheme->quota.goals);
 
 	scheme->wmarks = *wmarks;
 	scheme->wmarks.activated = true;
 
+	scheme->target_nid = target_nid;
+
 	return scheme;
 }
 
@@ -373,8 +419,12 @@ static void damon_free_scheme(struct damos *s)
 
 void damon_destroy_scheme(struct damos *s)
 {
+	struct damos_quota_goal *g, *g_next;
 	struct damos_filter *f, *next;
 
+	damos_for_each_quota_goal_safe(g, g_next, &s->quota)
+		damos_destroy_quota_goal(g);
+
 	damos_for_each_filter_safe(f, next, s)
 		damos_destroy_filter(f);
 	damon_del_scheme(s);
@@ -457,6 +507,8 @@ struct damon_ctx *damon_new_ctx(void)
 	ctx->next_ops_update_sis = 0;
 
 	mutex_init(&ctx->kdamond_lock);
+	mutex_init(&ctx->call_control_lock);
+	mutex_init(&ctx->walk_control_lock);
 
 	ctx->attrs.min_nr_regions = 10;
 	ctx->attrs.max_nr_regions = 1000;
@@ -505,7 +557,13 @@ static unsigned int damon_accesses_bp_to_nr_accesses(
 	return accesses_bp * damon_max_nr_accesses(attrs) / 10000;
 }
 
-/* convert nr_accesses to access ratio in bp (per 10,000) */
+/*
+ * Convert nr_accesses to access ratio in bp (per 10,000).
+ *
+ * Callers should ensure attrs.aggr_interval is not zero, like
+ * damon_update_monitoring_results() does .  Otherwise, divide-by-zero would
+ * happen.
+ */
 static unsigned int damon_nr_accesses_to_accesses_bp(
 		unsigned int nr_accesses, struct damon_attrs *attrs)
 {
@@ -619,6 +677,348 @@ void damon_set_schemes(struct damon_ctx *ctx, struct damos **schemes,
 		damon_add_scheme(ctx, schemes[i]);
 }
 
+static struct damos_quota_goal *damos_nth_quota_goal(
+		int n, struct damos_quota *q)
+{
+	struct damos_quota_goal *goal;
+	int i = 0;
+
+	damos_for_each_quota_goal(goal, q) {
+		if (i++ == n)
+			return goal;
+	}
+	return NULL;
+}
+
+static void damos_commit_quota_goal(
+		struct damos_quota_goal *dst, struct damos_quota_goal *src)
+{
+	dst->metric = src->metric;
+	dst->target_value = src->target_value;
+	if (dst->metric == DAMOS_QUOTA_USER_INPUT)
+		dst->current_value = src->current_value;
+	/* keep last_psi_total as is, since it will be updated in next cycle */
+}
+
+/**
+ * damos_commit_quota_goals() - Commit DAMOS quota goals to another quota.
+ * @dst:	The commit destination DAMOS quota.
+ * @src:	The commit source DAMOS quota.
+ *
+ * Copies user-specified parameters for quota goals from @src to @dst.  Users
+ * should use this function for quota goals-level parameters update of running
+ * DAMON contexts, instead of manual in-place updates.
+ *
+ * This function should be called from parameters-update safe context, like
+ * DAMON callbacks.
+ */
+int damos_commit_quota_goals(struct damos_quota *dst, struct damos_quota *src)
+{
+	struct damos_quota_goal *dst_goal, *next, *src_goal, *new_goal;
+	int i = 0, j = 0;
+
+	damos_for_each_quota_goal_safe(dst_goal, next, dst) {
+		src_goal = damos_nth_quota_goal(i++, src);
+		if (src_goal)
+			damos_commit_quota_goal(dst_goal, src_goal);
+		else
+			damos_destroy_quota_goal(dst_goal);
+	}
+	damos_for_each_quota_goal_safe(src_goal, next, src) {
+		if (j++ < i)
+			continue;
+		new_goal = damos_new_quota_goal(
+				src_goal->metric, src_goal->target_value);
+		if (!new_goal)
+			return -ENOMEM;
+		damos_add_quota_goal(dst, new_goal);
+	}
+	return 0;
+}
+
+static int damos_commit_quota(struct damos_quota *dst, struct damos_quota *src)
+{
+	int err;
+
+	dst->reset_interval = src->reset_interval;
+	dst->ms = src->ms;
+	dst->sz = src->sz;
+	err = damos_commit_quota_goals(dst, src);
+	if (err)
+		return err;
+	dst->weight_sz = src->weight_sz;
+	dst->weight_nr_accesses = src->weight_nr_accesses;
+	dst->weight_age = src->weight_age;
+	return 0;
+}
+
+static struct damos_filter *damos_nth_filter(int n, struct damos *s)
+{
+	struct damos_filter *filter;
+	int i = 0;
+
+	damos_for_each_filter(filter, s) {
+		if (i++ == n)
+			return filter;
+	}
+	return NULL;
+}
+
+static void damos_commit_filter_arg(
+		struct damos_filter *dst, struct damos_filter *src)
+{
+	switch (dst->type) {
+	case DAMOS_FILTER_TYPE_MEMCG:
+		dst->memcg_id = src->memcg_id;
+		break;
+	case DAMOS_FILTER_TYPE_ADDR:
+		dst->addr_range = src->addr_range;
+		break;
+	case DAMOS_FILTER_TYPE_TARGET:
+		dst->target_idx = src->target_idx;
+		break;
+	default:
+		break;
+	}
+}
+
+static void damos_commit_filter(
+		struct damos_filter *dst, struct damos_filter *src)
+{
+	dst->type = src->type;
+	dst->matching = src->matching;
+	damos_commit_filter_arg(dst, src);
+}
+
+static int damos_commit_filters(struct damos *dst, struct damos *src)
+{
+	struct damos_filter *dst_filter, *next, *src_filter, *new_filter;
+	int i = 0, j = 0;
+
+	damos_for_each_filter_safe(dst_filter, next, dst) {
+		src_filter = damos_nth_filter(i++, src);
+		if (src_filter)
+			damos_commit_filter(dst_filter, src_filter);
+		else
+			damos_destroy_filter(dst_filter);
+	}
+
+	damos_for_each_filter_safe(src_filter, next, src) {
+		if (j++ < i)
+			continue;
+
+		new_filter = damos_new_filter(
+				src_filter->type, src_filter->matching,
+				src_filter->allow);
+		if (!new_filter)
+			return -ENOMEM;
+		damos_commit_filter_arg(new_filter, src_filter);
+		damos_add_filter(dst, new_filter);
+	}
+	return 0;
+}
+
+static struct damos *damon_nth_scheme(int n, struct damon_ctx *ctx)
+{
+	struct damos *s;
+	int i = 0;
+
+	damon_for_each_scheme(s, ctx) {
+		if (i++ == n)
+			return s;
+	}
+	return NULL;
+}
+
+static int damos_commit(struct damos *dst, struct damos *src)
+{
+	int err;
+
+	dst->pattern = src->pattern;
+	dst->action = src->action;
+	dst->apply_interval_us = src->apply_interval_us;
+
+	err = damos_commit_quota(&dst->quota, &src->quota);
+	if (err)
+		return err;
+
+	dst->wmarks = src->wmarks;
+
+	err = damos_commit_filters(dst, src);
+	return err;
+}
+
+static int damon_commit_schemes(struct damon_ctx *dst, struct damon_ctx *src)
+{
+	struct damos *dst_scheme, *next, *src_scheme, *new_scheme;
+	int i = 0, j = 0, err;
+
+	damon_for_each_scheme_safe(dst_scheme, next, dst) {
+		src_scheme = damon_nth_scheme(i++, src);
+		if (src_scheme) {
+			err = damos_commit(dst_scheme, src_scheme);
+			if (err)
+				return err;
+		} else {
+			damon_destroy_scheme(dst_scheme);
+		}
+	}
+
+	damon_for_each_scheme_safe(src_scheme, next, src) {
+		if (j++ < i)
+			continue;
+		new_scheme = damon_new_scheme(&src_scheme->pattern,
+				src_scheme->action,
+				src_scheme->apply_interval_us,
+				&src_scheme->quota, &src_scheme->wmarks,
+				NUMA_NO_NODE);
+		if (!new_scheme)
+			return -ENOMEM;
+		err = damos_commit(new_scheme, src_scheme);
+		if (err) {
+			damon_destroy_scheme(new_scheme);
+			return err;
+		}
+		damon_add_scheme(dst, new_scheme);
+	}
+	return 0;
+}
+
+static struct damon_target *damon_nth_target(int n, struct damon_ctx *ctx)
+{
+	struct damon_target *t;
+	int i = 0;
+
+	damon_for_each_target(t, ctx) {
+		if (i++ == n)
+			return t;
+	}
+	return NULL;
+}
+
+/*
+ * The caller should ensure the regions of @src are
+ * 1. valid (end >= src) and
+ * 2. sorted by starting address.
+ *
+ * If @src has no region, @dst keeps current regions.
+ */
+static int damon_commit_target_regions(
+		struct damon_target *dst, struct damon_target *src)
+{
+	struct damon_region *src_region;
+	struct damon_addr_range *ranges;
+	int i = 0, err;
+
+	damon_for_each_region(src_region, src)
+		i++;
+	if (!i)
+		return 0;
+
+	ranges = kmalloc_array(i, sizeof(*ranges), GFP_KERNEL | __GFP_NOWARN);
+	if (!ranges)
+		return -ENOMEM;
+	i = 0;
+	damon_for_each_region(src_region, src)
+		ranges[i++] = src_region->ar;
+	err = damon_set_regions(dst, ranges, i);
+	kfree(ranges);
+	return err;
+}
+
+static int damon_commit_target(
+		struct damon_target *dst, bool dst_has_pid,
+		struct damon_target *src, bool src_has_pid)
+{
+	int err;
+
+	err = damon_commit_target_regions(dst, src);
+	if (err)
+		return err;
+	if (dst_has_pid)
+		put_pid(dst->pid);
+	if (src_has_pid)
+		get_pid(src->pid);
+	dst->pid = src->pid;
+	return 0;
+}
+
+static int damon_commit_targets(
+		struct damon_ctx *dst, struct damon_ctx *src)
+{
+	struct damon_target *dst_target, *next, *src_target, *new_target;
+	int i = 0, j = 0, err;
+
+	damon_for_each_target_safe(dst_target, next, dst) {
+		src_target = damon_nth_target(i++, src);
+		if (src_target) {
+			err = damon_commit_target(
+					dst_target, damon_target_has_pid(dst),
+					src_target, damon_target_has_pid(src));
+			if (err)
+				return err;
+		} else {
+			if (damon_target_has_pid(dst))
+				put_pid(dst_target->pid);
+			damon_destroy_target(dst_target);
+		}
+	}
+
+	damon_for_each_target_safe(src_target, next, src) {
+		if (j++ < i)
+			continue;
+		new_target = damon_new_target();
+		if (!new_target)
+			return -ENOMEM;
+		err = damon_commit_target(new_target, false,
+				src_target, damon_target_has_pid(src));
+		if (err) {
+			damon_destroy_target(new_target);
+			return err;
+		}
+		damon_add_target(dst, new_target);
+	}
+	return 0;
+}
+
+/**
+ * damon_commit_ctx() - Commit parameters of a DAMON context to another.
+ * @dst:	The commit destination DAMON context.
+ * @src:	The commit source DAMON context.
+ *
+ * This function copies user-specified parameters from @src to @dst and update
+ * the internal status and results accordingly.  Users should use this function
+ * for context-level parameters update of running context, instead of manual
+ * in-place updates.
+ *
+ * This function should be called from parameters-update safe context, like
+ * DAMON callbacks.
+ */
+int damon_commit_ctx(struct damon_ctx *dst, struct damon_ctx *src)
+{
+	int err;
+
+	err = damon_commit_schemes(dst, src);
+	if (err)
+		return err;
+	err = damon_commit_targets(dst, src);
+	if (err)
+		return err;
+	/*
+	 * schemes and targets should be updated first, since
+	 * 1. damon_set_attrs() updates monitoring results of targets and
+	 * next_apply_sis of schemes, and
+	 * 2. ops update should be done after pid handling is done (target
+	 *    committing require putting pids).
+	 */
+	err = damon_set_attrs(dst, &src->attrs);
+	if (err)
+		return err;
+	dst->ops = src->ops;
+
+	return 0;
+}
+
 /**
  * damon_nr_running_ctxs() - Return number of currently running contexts.
  */
@@ -768,6 +1168,94 @@ int damon_stop(struct damon_ctx **ctxs, int nr_ctxs)
 	return err;
 }
 
+static bool damon_is_running(struct damon_ctx *ctx)
+{
+	bool running;
+
+	mutex_lock(&ctx->kdamond_lock);
+	running = ctx->kdamond != NULL;
+	mutex_unlock(&ctx->kdamond_lock);
+	return running;
+}
+
+/**
+ * damon_call() - Invoke a given function on DAMON worker thread (kdamond).
+ * @ctx:	DAMON context to call the function for.
+ * @control:	Control variable of the call request.
+ *
+ * Ask DAMON worker thread (kdamond) of @ctx to call a function with an
+ * argument data that respectively passed via &damon_call_control->fn and
+ * &damon_call_control->data of @control, and wait until the kdamond finishes
+ * handling of the request.
+ *
+ * The kdamond executes the function with the argument in the main loop, just
+ * after a sampling of the iteration is finished.  The function can hence
+ * safely access the internal data of the &struct damon_ctx without additional
+ * synchronization.  The return value of the function will be saved in
+ * &damon_call_control->return_code.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int damon_call(struct damon_ctx *ctx, struct damon_call_control *control)
+{
+	init_completion(&control->completion);
+	control->canceled = false;
+
+	mutex_lock(&ctx->call_control_lock);
+	if (ctx->call_control) {
+		mutex_unlock(&ctx->call_control_lock);
+		return -EBUSY;
+	}
+	ctx->call_control = control;
+	mutex_unlock(&ctx->call_control_lock);
+	if (!damon_is_running(ctx))
+		return -EINVAL;
+	wait_for_completion(&control->completion);
+	if (control->canceled)
+		return -ECANCELED;
+	return 0;
+}
+
+/**
+ * damos_walk() - Invoke a given functions while DAMOS walk regions.
+ * @ctx:	DAMON context to call the functions for.
+ * @control:	Control variable of the walk request.
+ *
+ * Ask DAMON worker thread (kdamond) of @ctx to call a function for each region
+ * that the kdamond will apply DAMOS action to, and wait until the kdamond
+ * finishes handling of the request.
+ *
+ * The kdamond executes the given function in the main loop, for each region
+ * just after it applied any DAMOS actions of @ctx to it.  The invocation is
+ * made only within one &damos->apply_interval_us since damos_walk()
+ * invocation, for each scheme.  The given callback function can hence safely
+ * access the internal data of &struct damon_ctx and &struct damon_region that
+ * each of the scheme will apply the action for next interval, without
+ * additional synchronizations against the kdamond.  If every scheme of @ctx
+ * passed at least one &damos->apply_interval_us, kdamond marks the request as
+ * completed so that damos_walk() can wakeup and return.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int damos_walk(struct damon_ctx *ctx, struct damos_walk_control *control)
+{
+	init_completion(&control->completion);
+	control->canceled = false;
+	mutex_lock(&ctx->walk_control_lock);
+	if (ctx->walk_control) {
+		mutex_unlock(&ctx->walk_control_lock);
+		return -EBUSY;
+	}
+	ctx->walk_control = control;
+	mutex_unlock(&ctx->walk_control_lock);
+	if (!damon_is_running(ctx))
+		return -EINVAL;
+	wait_for_completion(&control->completion);
+	if (control->canceled)
+		return -ECANCELED;
+	return 0;
+}
+
 /*
  * Reset the aggregated monitoring results ('nr_accesses' of each region).
  */
@@ -878,16 +1366,18 @@ static bool damos_skip_charged_region(struct damon_target *t,
 }
 
 static void damos_update_stat(struct damos *s,
-		unsigned long sz_tried, unsigned long sz_applied)
+		unsigned long sz_tried, unsigned long sz_applied,
+		unsigned long sz_ops_filter_passed)
 {
 	s->stat.nr_tried++;
 	s->stat.sz_tried += sz_tried;
 	if (sz_applied)
 		s->stat.nr_applied++;
 	s->stat.sz_applied += sz_applied;
+	s->stat.sz_ops_filter_passed += sz_ops_filter_passed;
 }
 
-static bool __damos_filter_out(struct damon_ctx *ctx, struct damon_target *t,
+static bool damos_filter_match(struct damon_ctx *ctx, struct damon_target *t,
 		struct damon_region *r, struct damos_filter *filter)
 {
 	bool matched = false;
@@ -940,13 +1430,103 @@ static bool damos_filter_out(struct damon_ctx *ctx, struct damon_target *t,
 {
 	struct damos_filter *filter;
 
+	s->core_filters_allowed = false;
 	damos_for_each_filter(filter, s) {
-		if (__damos_filter_out(ctx, t, r, filter))
-			return true;
+		if (damos_filter_match(ctx, t, r, filter)) {
+			if (filter->allow)
+				s->core_filters_allowed = true;
+			return !filter->allow;
+		}
 	}
 	return false;
 }
 
+/*
+ * damos_walk_call_walk() - Call &damos_walk_control->walk_fn.
+ * @ctx:	The context of &damon_ctx->walk_control.
+ * @t:		The monitoring target of @r that @s will be applied.
+ * @r:		The region of @t that @s will be applied.
+ * @s:		The scheme of @ctx that will be applied to @r.
+ *
+ * This function is called from kdamond whenever it asked the operation set to
+ * apply a DAMOS scheme action to a region.  If a DAMOS walk request is
+ * installed by damos_walk() and not yet uninstalled, invoke it.
+ */
+static void damos_walk_call_walk(struct damon_ctx *ctx, struct damon_target *t,
+		struct damon_region *r, struct damos *s,
+		unsigned long sz_filter_passed)
+{
+	struct damos_walk_control *control;
+
+	mutex_lock(&ctx->walk_control_lock);
+	control = ctx->walk_control;
+	mutex_unlock(&ctx->walk_control_lock);
+	if (!control)
+		return;
+	control->walk_fn(control->data, ctx, t, r, s, sz_filter_passed);
+}
+
+/*
+ * damos_walk_complete() - Complete DAMOS walk request if all walks are done.
+ * @ctx:	The context of &damon_ctx->walk_control.
+ * @s:		A scheme of @ctx that all walks are now done.
+ *
+ * This function is called when kdamond finished applying the action of a DAMOS
+ * scheme to all regions that eligible for the given &damos->apply_interval_us.
+ * If every scheme of @ctx including @s now finished walking for at least one
+ * &damos->apply_interval_us, this function makrs the handling of the given
+ * DAMOS walk request is done, so that damos_walk() can wake up and return.
+ */
+static void damos_walk_complete(struct damon_ctx *ctx, struct damos *s)
+{
+	struct damos *siter;
+	struct damos_walk_control *control;
+
+	mutex_lock(&ctx->walk_control_lock);
+	control = ctx->walk_control;
+	mutex_unlock(&ctx->walk_control_lock);
+	if (!control)
+		return;
+
+	s->walk_completed = true;
+	/* if all schemes completed, signal completion to walker */
+	damon_for_each_scheme(siter, ctx) {
+		if (!siter->walk_completed)
+			return;
+	}
+	complete(&control->completion);
+	mutex_lock(&ctx->walk_control_lock);
+	ctx->walk_control = NULL;
+	mutex_unlock(&ctx->walk_control_lock);
+}
+
+/*
+ * damos_walk_cancel() - Cancel the current DAMOS walk request.
+ * @ctx:	The context of &damon_ctx->walk_control.
+ *
+ * This function is called when @ctx is deactivated by DAMOS watermarks, DAMOS
+ * walk is requested but there is no DAMOS scheme to walk for, or the kdamond
+ * is already out of the main loop and therefore gonna be terminated, and hence
+ * cannot continue the walks.  This function therefore marks the walk request
+ * as canceled, so that damos_walk() can wake up and return.
+ */
+static void damos_walk_cancel(struct damon_ctx *ctx)
+{
+	struct damos_walk_control *control;
+
+	mutex_lock(&ctx->walk_control_lock);
+	control = ctx->walk_control;
+	mutex_unlock(&ctx->walk_control_lock);
+
+	if (!control)
+		return;
+	control->canceled = true;
+	complete(&control->completion);
+	mutex_lock(&ctx->walk_control_lock);
+	ctx->walk_control = NULL;
+	mutex_unlock(&ctx->walk_control_lock);
+}
+
 static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 		struct damon_region *r, struct damos *s)
 {
@@ -954,6 +1534,7 @@ 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;
+	unsigned long sz_ops_filter_passed = 0;
 	int err = 0;
 	/*
 	 * We plan to support multiple context per kdamond, as DAMON sysfs
@@ -999,8 +1580,10 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 		if (!err) {
 			trace_damos_before_apply(cidx, sidx, tidx, r,
 					damon_nr_regions(t), do_trace);
-			sz_applied = c->ops.apply_scheme(c, t, r, s);
+			sz_applied = c->ops.apply_scheme(c, t, r, s,
+					&sz_ops_filter_passed);
 		}
+		damos_walk_call_walk(c, t, r, s, sz_ops_filter_passed);
 		ktime_get_coarse_ts64(&end);
 		quota->total_charged_ns += timespec64_to_ns(&end) -
 			timespec64_to_ns(&begin);
@@ -1014,7 +1597,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
 		r->age = 0;
 
 update_stat:
-	damos_update_stat(s, sz, sz_applied);
+	damos_update_stat(s, sz, sz_applied, sz_ops_filter_passed);
 }
 
 static void damon_do_apply_schemes(struct damon_ctx *c,
@@ -1026,7 +1609,7 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
 	damon_for_each_scheme(s, c) {
 		struct damos_quota *quota = &s->quota;
 
-		if (c->passed_sample_intervals != s->next_apply_sis)
+		if (c->passed_sample_intervals < s->next_apply_sis)
 			continue;
 
 		if (!s->wmarks.activated)
@@ -1070,34 +1653,105 @@ static unsigned long damon_feed_loop_next_input(unsigned long last_input,
 		unsigned long score)
 {
 	const unsigned long goal = 10000;
-	unsigned long score_goal_diff = max(goal, score) - min(goal, score);
-	unsigned long score_goal_diff_bp = score_goal_diff * 10000 / goal;
-	unsigned long compensation = last_input * score_goal_diff_bp / 10000;
 	/* Set minimum input as 10000 to avoid compensation be zero */
 	const unsigned long min_input = 10000;
+	unsigned long score_goal_diff, compensation;
+	bool over_achieving = score > goal;
 
-	if (goal > score)
+	if (score == goal)
+		return last_input;
+	if (score >= goal * 2)
+		return min_input;
+
+	if (over_achieving)
+		score_goal_diff = score - goal;
+	else
+		score_goal_diff = goal - score;
+
+	if (last_input < ULONG_MAX / score_goal_diff)
+		compensation = last_input * score_goal_diff / goal;
+	else
+		compensation = last_input / goal * score_goal_diff;
+
+	if (over_achieving)
+		return max(last_input - compensation, min_input);
+	if (last_input < ULONG_MAX - compensation)
 		return last_input + compensation;
-	if (last_input > compensation + min_input)
-		return last_input - compensation;
-	return min_input;
+	return ULONG_MAX;
 }
 
-/* Shouldn't be called if quota->ms, quota->sz, and quota->get_score unset */
+#ifdef CONFIG_PSI
+
+static u64 damos_get_some_mem_psi_total(void)
+{
+	if (static_branch_likely(&psi_disabled))
+		return 0;
+	return div_u64(psi_system.total[PSI_AVGS][PSI_MEM * 2],
+			NSEC_PER_USEC);
+}
+
+#else	/* CONFIG_PSI */
+
+static inline u64 damos_get_some_mem_psi_total(void)
+{
+	return 0;
+};
+
+#endif	/* CONFIG_PSI */
+
+static void damos_set_quota_goal_current_value(struct damos_quota_goal *goal)
+{
+	u64 now_psi_total;
+
+	switch (goal->metric) {
+	case DAMOS_QUOTA_USER_INPUT:
+		/* User should already set goal->current_value */
+		break;
+	case DAMOS_QUOTA_SOME_MEM_PSI_US:
+		now_psi_total = damos_get_some_mem_psi_total();
+		goal->current_value = now_psi_total - goal->last_psi_total;
+		goal->last_psi_total = now_psi_total;
+		break;
+	default:
+		break;
+	}
+}
+
+/* Return the highest score since it makes schemes least aggressive */
+static unsigned long damos_quota_score(struct damos_quota *quota)
+{
+	struct damos_quota_goal *goal;
+	unsigned long highest_score = 0;
+
+	damos_for_each_quota_goal(goal, quota) {
+		damos_set_quota_goal_current_value(goal);
+		highest_score = max(highest_score,
+				goal->current_value * 10000 /
+				goal->target_value);
+	}
+
+	return highest_score;
+}
+
+/*
+ * Called only if quota->ms, or quota->sz are set, or quota->goals is not empty
+ */
 static void damos_set_effective_quota(struct damos_quota *quota)
 {
 	unsigned long throughput;
-	unsigned long esz;
+	unsigned long esz = ULONG_MAX;
 
-	if (!quota->ms && !quota->get_score) {
+	if (!quota->ms && list_empty(&quota->goals)) {
 		quota->esz = quota->sz;
 		return;
 	}
 
-	if (quota->get_score) {
+	if (!list_empty(&quota->goals)) {
+		unsigned long score = damos_quota_score(quota);
+
 		quota->esz_bp = damon_feed_loop_next_input(
 				max(quota->esz_bp, 10000UL),
-				quota->get_score(quota->get_score_arg));
+				score);
 		esz = quota->esz_bp / 10000;
 	}
 
@@ -1107,10 +1761,7 @@ static void damos_set_effective_quota(struct damos_quota *quota)
 				quota->total_charged_ns;
 		else
 			throughput = PAGE_SIZE * 1024;
-		if (quota->get_score)
-			esz = min(throughput * quota->ms, esz);
-		else
-			esz = throughput * quota->ms;
+		esz = min(throughput * quota->ms, esz);
 	}
 
 	if (quota->sz && quota->sz < esz)
@@ -1127,7 +1778,7 @@ static void damos_adjust_quota(struct damon_ctx *c, struct damos *s)
 	unsigned long cumulated_sz;
 	unsigned int score, max_score = 0;
 
-	if (!quota->ms && !quota->sz && !quota->get_score)
+	if (!quota->ms && !quota->sz && list_empty(&quota->goals))
 		return;
 
 	/* New charge window starts */
@@ -1145,13 +1796,16 @@ static void damos_adjust_quota(struct damon_ctx *c, struct damos *s)
 		return;
 
 	/* Fill up the score histogram */
-	memset(quota->histogram, 0, sizeof(quota->histogram));
+	memset(c->regions_score_histogram, 0,
+			sizeof(*c->regions_score_histogram) *
+			(DAMOS_MAX_SCORE + 1));
 	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);
+			c->regions_score_histogram[score] +=
+				damon_sz_region(r);
 			if (score > max_score)
 				max_score = score;
 		}
@@ -1159,7 +1813,7 @@ static void damos_adjust_quota(struct damon_ctx *c, struct damos *s)
 
 	/* Set the min score limit */
 	for (cumulated_sz = 0, score = max_score; ; score--) {
-		cumulated_sz += quota->histogram[score];
+		cumulated_sz += c->regions_score_histogram[score];
 		if (cumulated_sz >= quota->esz || !score)
 			break;
 	}
@@ -1176,7 +1830,7 @@ static void kdamond_apply_schemes(struct damon_ctx *c)
 	bool has_schemes_to_apply = false;
 
 	damon_for_each_scheme(s, c) {
-		if (c->passed_sample_intervals != s->next_apply_sis)
+		if (c->passed_sample_intervals < s->next_apply_sis)
 			continue;
 
 		if (!s->wmarks.activated)
@@ -1196,9 +1850,10 @@ static void kdamond_apply_schemes(struct damon_ctx *c)
 	}
 
 	damon_for_each_scheme(s, c) {
-		if (c->passed_sample_intervals != s->next_apply_sis)
+		if (c->passed_sample_intervals < s->next_apply_sis)
 			continue;
-		s->next_apply_sis +=
+		damos_walk_complete(c, s);
+		s->next_apply_sis = c->passed_sample_intervals +
 			(s->apply_interval_us ? s->apply_interval_us :
 			 c->attrs.aggr_interval) / sample_interval;
 	}
@@ -1257,14 +1912,31 @@ static void damon_merge_regions_of(struct damon_target *t, unsigned int thres,
  * access frequencies are similar.  This is for minimizing the monitoring
  * overhead under the dynamically changeable access pattern.  If a merge was
  * unnecessarily made, later 'kdamond_split_regions()' will revert it.
+ *
+ * The total number of regions could be higher than the user-defined limit,
+ * max_nr_regions for some cases.  For example, the user can update
+ * max_nr_regions to a number that lower than the current number of regions
+ * while DAMON is running.  For such a case, repeat merging until the limit is
+ * met while increasing @threshold up to possible maximum level.
  */
 static void kdamond_merge_regions(struct damon_ctx *c, unsigned int threshold,
 				  unsigned long sz_limit)
 {
 	struct damon_target *t;
-
-	damon_for_each_target(t, c)
-		damon_merge_regions_of(t, threshold, sz_limit);
+	unsigned int nr_regions;
+	unsigned int max_thres;
+
+	max_thres = c->attrs.aggr_interval /
+		(c->attrs.sample_interval ?  c->attrs.sample_interval : 1);
+	do {
+		nr_regions = 0;
+		damon_for_each_target(t, c) {
+			damon_merge_regions_of(t, threshold, sz_limit);
+			nr_regions += damon_nr_regions(t);
+		}
+		threshold = max(1, threshold * 2);
+	} while (nr_regions > c->attrs.max_nr_regions &&
+			threshold / 2 < max_thres);
 }
 
 /*
@@ -1380,12 +2052,14 @@ static bool kdamond_need_stop(struct damon_ctx *ctx)
 	return true;
 }
 
-static unsigned long damos_wmark_metric_value(enum damos_wmark_metric metric)
+static int damos_get_wmark_metric_value(enum damos_wmark_metric metric,
+					unsigned long *metric_value)
 {
 	switch (metric) {
 	case DAMOS_WMARK_FREE_MEM_RATE:
-		return global_zone_page_state(NR_FREE_PAGES) * 1000 /
+		*metric_value = global_zone_page_state(NR_FREE_PAGES) * 1000 /
 		       totalram_pages();
+		return 0;
 	default:
 		break;
 	}
@@ -1400,17 +2074,15 @@ static unsigned long damos_wmark_wait_us(struct damos *scheme)
 {
 	unsigned long metric;
 
-	if (scheme->wmarks.metric == DAMOS_WMARK_NONE)
+	if (damos_get_wmark_metric_value(scheme->wmarks.metric, &metric))
 		return 0;
 
-	metric = damos_wmark_metric_value(scheme->wmarks.metric);
 	/* higher than high watermark or lower than low watermark */
 	if (metric > scheme->wmarks.high || scheme->wmarks.low > metric) {
 		if (scheme->wmarks.activated)
 			pr_debug("deactivate a scheme (%d) for %s wmark\n",
-					scheme->action,
-					metric > scheme->wmarks.high ?
-					"high" : "low");
+				 scheme->action,
+				 str_high_low(metric > scheme->wmarks.high));
 		scheme->wmarks.activated = false;
 		return scheme->wmarks.interval;
 	}
@@ -1428,11 +2100,43 @@ static unsigned long damos_wmark_wait_us(struct damos *scheme)
 
 static void kdamond_usleep(unsigned long usecs)
 {
-	/* See Documentation/timers/timers-howto.rst for the thresholds */
-	if (usecs > 20 * USEC_PER_MSEC)
+	if (usecs >= USLEEP_RANGE_UPPER_BOUND)
 		schedule_timeout_idle(usecs_to_jiffies(usecs));
 	else
-		usleep_idle_range(usecs, usecs + 1);
+		usleep_range_idle(usecs, usecs + 1);
+}
+
+/*
+ * kdamond_call() - handle damon_call_control.
+ * @ctx:	The &struct damon_ctx of the kdamond.
+ * @cancel:	Whether to cancel the invocation of the function.
+ *
+ * If there is a &struct damon_call_control request that registered via
+ * &damon_call() on @ctx, do or cancel the invocation of the function depending
+ * on @cancel.  @cancel is set when the kdamond is deactivated by DAMOS
+ * watermarks, or the kdamond is already out of the main loop and therefore
+ * will be terminated.
+ */
+static void kdamond_call(struct damon_ctx *ctx, bool cancel)
+{
+	struct damon_call_control *control;
+	int ret = 0;
+
+	mutex_lock(&ctx->call_control_lock);
+	control = ctx->call_control;
+	mutex_unlock(&ctx->call_control_lock);
+	if (!control)
+		return;
+	if (cancel) {
+		control->canceled = true;
+	} else {
+		ret = control->fn(control->data);
+		control->return_code = ret;
+	}
+	complete(&control->completion);
+	mutex_lock(&ctx->call_control_lock);
+	ctx->call_control = NULL;
+	mutex_unlock(&ctx->call_control_lock);
 }
 
 /* Returns negative error code if it's not activated but should return */
@@ -1459,6 +2163,8 @@ static int kdamond_wait_activation(struct damon_ctx *ctx)
 		if (ctx->callback.after_wmarks_check &&
 				ctx->callback.after_wmarks_check(ctx))
 			break;
+		kdamond_call(ctx, true);
+		damos_walk_cancel(ctx);
 	}
 	return -EBUSY;
 }
@@ -1502,6 +2208,10 @@ static int kdamond_fn(void *data)
 		ctx->ops.init(ctx);
 	if (ctx->callback.before_start && ctx->callback.before_start(ctx))
 		goto done;
+	ctx->regions_score_histogram = kmalloc_array(DAMOS_MAX_SCORE + 1,
+			sizeof(*ctx->regions_score_histogram), GFP_KERNEL);
+	if (!ctx->regions_score_histogram)
+		goto done;
 
 	sz_limit = damon_region_sz_limit(ctx);
 
@@ -1525,6 +2235,7 @@ static int kdamond_fn(void *data)
 		if (ctx->callback.after_sampling &&
 				ctx->callback.after_sampling(ctx))
 			break;
+		kdamond_call(ctx, false);
 
 		kdamond_usleep(sample_interval);
 		ctx->passed_sample_intervals++;
@@ -1532,7 +2243,7 @@ static int kdamond_fn(void *data)
 		if (ctx->ops.check_accesses)
 			max_nr_accesses = ctx->ops.check_accesses(ctx);
 
-		if (ctx->passed_sample_intervals == next_aggregation_sis) {
+		if (ctx->passed_sample_intervals >= next_aggregation_sis) {
 			kdamond_merge_regions(ctx,
 					max_nr_accesses / 10,
 					sz_limit);
@@ -1547,10 +2258,12 @@ static int kdamond_fn(void *data)
 		 */
 		if (!list_empty(&ctx->schemes))
 			kdamond_apply_schemes(ctx);
+		else
+			damos_walk_cancel(ctx);
 
 		sample_interval = ctx->attrs.sample_interval ?
 			ctx->attrs.sample_interval : 1;
-		if (ctx->passed_sample_intervals == next_aggregation_sis) {
+		if (ctx->passed_sample_intervals >= next_aggregation_sis) {
 			ctx->next_aggregation_sis = next_aggregation_sis +
 				ctx->attrs.aggr_interval / sample_interval;
 
@@ -1560,7 +2273,7 @@ static int kdamond_fn(void *data)
 				ctx->ops.reset_aggregated(ctx);
 		}
 
-		if (ctx->passed_sample_intervals == next_ops_update_sis) {
+		if (ctx->passed_sample_intervals >= next_ops_update_sis) {
 			ctx->next_ops_update_sis = next_ops_update_sis +
 				ctx->attrs.ops_update_interval /
 				sample_interval;
@@ -1579,12 +2292,16 @@ done:
 		ctx->callback.before_terminate(ctx);
 	if (ctx->ops.cleanup)
 		ctx->ops.cleanup(ctx);
+	kfree(ctx->regions_score_histogram);
 
 	pr_debug("kdamond (%d) finishes\n", current->pid);
 	mutex_lock(&ctx->kdamond_lock);
 	ctx->kdamond = NULL;
 	mutex_unlock(&ctx->kdamond_lock);
 
+	kdamond_call(ctx, true);
+	damos_walk_cancel(ctx);
+
 	mutex_lock(&damon_lock);
 	nr_running_ctxs--;
 	if (!nr_running_ctxs && running_exclusive_ctxs)
@@ -1750,4 +2467,4 @@ static int __init damon_init(void)
 
 subsys_initcall(damon_init);
 
-#include "core-test.h"
+#include "tests/core-kunit.h"