[RFC PATCH 05/16] mm/damon/core: implement damon_probe_hits_wsum()

[SJ Park <sj@kernel.org>]

When damon_probe->weight is set, the weighted sum of probe hits will be
useful.  It will be useful for not only the users but also DAMON
internal logics like regions merging.  Implement a function for
calculating it.

Signed-off-by: SJ Park <sj@kernel.org>
---
 include/linux/damon.h |  2 ++
 mm/damon/core.c       | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 62caa67a3c40c..c43986a3aa16c 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -1011,6 +1011,8 @@ unsigned int damon_nr_accesses_mvsum(struct damon_region *r,
 		struct damon_ctx *ctx);
 unsigned char damon_probe_hits_mvsum(int probe_idx, struct damon_region *r,
 		struct damon_ctx *ctx);
+unsigned int damon_probe_hits_wsum(struct damon_region *r, bool last,
+		struct damon_ctx *ctx);
 
 int damon_set_regions(struct damon_target *t, struct damon_addr_range *ranges,
 		unsigned int nr_ranges, unsigned long min_region_sz);
diff --git a/mm/damon/core.c b/mm/damon/core.c
index e42f512d87a11..d7d1e27d767eb 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -390,6 +390,30 @@ static bool damon_is_last_region(struct damon_region *r,
 	return list_is_last(&r->list, &t->regions_list);
 }
 
+/**
+ * damon_probe_hits_wsum() - Returns probe hits weighted sum of a region.
+ * @r:		region to get the weigted sum of.
+ * @last:	if the request is for last-window agggregated probe hits.
+ * @ctx:	context of &r.
+ *
+ * Return: the weighted sum of probe hits of the region.
+ */
+unsigned int damon_probe_hits_wsum(struct damon_region *r, bool last,
+		struct damon_ctx *ctx)
+{
+	struct damon_probe *probe;
+	unsigned int sum = 0;
+	int i = 0;
+
+	damon_for_each_probe(probe, ctx) {
+		if (last)
+			sum += r->last_probe_hits[i++] * probe->weight;
+		else
+			sum += r->probe_hits[i++] * probe->weight;
+	}
+	return sum;
+}
+
 /*
  * Check whether a region is intersecting an address range
  *
-- 
2.47.3