1 files changed, 160 insertions, 106 deletions

diff --git a/mm/damon/core.c b/mm/damon/core.c
index 36d098d06c55..ceec75b88ef9 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -694,6 +694,115 @@ 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 a quota of a scheme has exceeded in a quota charge window, the scheme's
+ * action would applied to only a part of the target access pattern fulfilling
+ * regions.  To avoid applying the scheme action to only already applied
+ * regions, DAMON skips applying the scheme action to the regions that charged
+ * in the previous charge window.
+ *
+ * This function checks if a given region should be skipped or not for the
+ * reason.  If only the starting part of the region has previously charged,
+ * this function splits the region into two so that the second one covers the
+ * area that not charged in the previous charge widnow and saves the second
+ * region in *rp and returns false, so that the caller can apply DAMON action
+ * to the second one.
+ *
+ * Return: true if the region should be entirely skipped, false otherwise.
+ */
+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 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)
+{
+	struct damos_quota *quota = &s->quota;
+	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) {
+			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);
+		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);
+		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:
+	damos_update_stat(s, sz, sz_applied);
+}
+
 static void damon_do_apply_schemes(struct damon_ctx *c,
 				   struct damon_target *t,
 				   struct damon_region *r)
@@ -702,9 +811,6 @@ 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 = damon_sz_region(r);
-		struct timespec64 begin, end;
-		unsigned long sz_applied = 0;
 
 		if (!s->wmarks.activated)
 			continue;
@@ -713,70 +819,13 @@ 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 */
-		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);
 	}
 }
 
@@ -803,59 +852,64 @@ 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) {