mm/damon/core: remove nr_accesses_bp setups and updates

DAMON core sets and updates nr_accesses_bp in multiple places.  It
explains how delicate it is.  The field is no more being used for any real
purpose, and replaced by a simpler function.  Remove the setups and
updates.

Link: https://lore.kernel.org/20260630040812.149729-14-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 2 insertions, 20 deletions

diff --git a/mm/damon/core.c b/mm/damon/core.c
index d2b7609dcf5a..ef0b87f2c035 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -302,7 +302,6 @@ struct damon_region *damon_new_region(unsigned long start, unsigned long end)
 	region->ar.start = start;
 	region->ar.end = end;
 	region->nr_accesses = 0;
-	region->nr_accesses_bp = 0;
 	for (i = 0; i < DAMON_MAX_PROBES; i++)
 		region->probe_hits[i] = 0;
 	INIT_LIST_HEAD(&region->list);
@@ -889,20 +888,17 @@ static void damon_update_monitoring_result(struct damon_region *r,
 {
 	r->last_nr_accesses = damon_nr_accesses_for_new_attrs(
 			r->last_nr_accesses, old_attrs, new_attrs);
-	if (!aggregating) {
+	if (!aggregating)
 		r->nr_accesses = damon_nr_accesses_for_new_attrs(
 				r->nr_accesses, old_attrs, new_attrs);
-		r->nr_accesses_bp = r->nr_accesses * 10000;
-	} else {
+	else
 		/*
 		 * if this is called in the middle of the aggregation, reset
 		 * the aggregations we made so far for this aggregation
 		 * interval.  In other words, make the status like
 		 * kdamond_reset_aggregated() is called.
 		 */
-		r->nr_accesses_bp = r->last_nr_accesses * 10000;
 		r->nr_accesses = 0;
-	}
 	r->age = damon_age_for_new_attrs(r->age, old_attrs, new_attrs);
 }
 
@@ -3129,7 +3125,6 @@ static void damon_merge_two_regions(struct damon_target *t,
 
 	l->nr_accesses = (l->nr_accesses * sz_l + r->nr_accesses * sz_r) /
 			(sz_l + sz_r);
-	l->nr_accesses_bp = l->nr_accesses * 10000;
 	l->age = (l->age * sz_l + r->age * sz_r) / (sz_l + sz_r);
 	l->ar.end = r->ar.end;
 	/* todo: do this for only installed probes */
@@ -3241,7 +3236,6 @@ static void damon_split_region_at(struct damon_target *t,
 
 	new->age = r->age;
 	new->last_nr_accesses = r->last_nr_accesses;
-	new->nr_accesses_bp = r->nr_accesses_bp;
 	new->nr_accesses = r->nr_accesses;
 	/* todo: do this for only installed probes */
 	memcpy(new->probe_hits, r->probe_hits, sizeof(r->probe_hits));
@@ -3849,18 +3843,6 @@ static unsigned int damon_moving_sum(unsigned int mvsum, unsigned int nomvsum,
 void damon_update_region_access_rate(struct damon_region *r, bool accessed,
 		struct damon_attrs *attrs)
 {
-	unsigned int len_window = 1;
-
-	/*
-	 * sample_interval can be zero, but cannot be larger than
-	 * aggr_interval, owing to validation of damon_set_attrs().
-	 */
-	if (attrs->sample_interval)
-		len_window = damon_max_nr_accesses(attrs);
-	r->nr_accesses_bp = damon_moving_sum(r->nr_accesses_bp,
-			r->last_nr_accesses * 10000, len_window,
-			accessed ? 10000 : 0);
-
 	if (accessed)
 		r->nr_accesses++;
 }