[RFC PATCH 16/19] mm/damon: trace probe_hits

SeongJae Park
2026-04-26T20:52:40Z

Introduce a new tracepoint for exposing the per-region per-probe
positive sample count via tracefs.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
include/trace/events/damon.h | 41 ++++++++++++++++++++++++++++++++++++
mm/damon/core.c | 1 +
2 files changed, 42 insertions(+)

diff --git a/include/trace/events/damon.h b/include/trace/events/damon.h
index 7e25f4469b81b..121d7bc3a2c27 100644
--- a/include/trace/events/damon.h
+++ b/include/trace/events/damon.h
@@ -130,6 +130,47 @@ TRACE_EVENT(damon_monitor_intervals_tune,
TP_printk("sample_us=%lu", __entry->sample_us)
);

+TRACE_EVENT(damon_aggregated_v2,
+
+ TP_PROTO(unsigned int target_id, struct damon_region *r,
+ unsigned int nr_regions),
+
+ TP_ARGS(target_id, r, nr_regions),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, target_id)
+ __field(unsigned int, nr_regions)
+ __field(unsigned long, start)
+ __field(unsigned long, end)
+ __field(unsigned int, nr_accesses)
+ __field(unsigned int, age)
+ __field(unsigned char, probe_hit0)
+ __field(unsigned char, probe_hit1)
+ __field(unsigned char, probe_hit2)
+ __field(unsigned char, probe_hit3)
+ ),
+
+ TP_fast_assign(
+ __entry->target_id = target_id;
+ __entry->nr_regions = nr_regions;
+ __entry->start = r->ar.start;
+ __entry->end = r->ar.end;
+ __entry->nr_accesses = r->nr_accesses;
+ __entry->age = r->age;
+ __entry->probe_hit0 = r->probe_hits[0];
+ __entry->probe_hit1 = r->probe_hits[1];
+ __entry->probe_hit2 = r->probe_hits[2];
+ __entry->probe_hit3 = r->probe_hits[3];
+ ),
+
+ TP_printk("target_id=%lu nr_regions=%u %lu-%lu: %u %u %hhu %hhu %hhu %hhu",
+ __entry->target_id, __entry->nr_regions,
+ __entry->start, __entry->end,
+ __entry->nr_accesses, __entry->age,
+ __entry->probe_hit0, __entry->probe_hit1,
+ __entry->probe_hit2, __entry->probe_hit3)
+);
+
TRACE_EVENT(damon_aggregated,

TP_PROTO(unsigned int target_id, struct damon_region *r,
diff --git a/mm/damon/core.c b/mm/damon/core.c
index fe14971d72747..54834b74efef4 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1924,6 +1924,7 @@ static void kdamond_reset_aggregated(struct damon_ctx *c)
int i;

trace_damon_aggregated(ti, r, damon_nr_regions(t));
+ trace_damon_aggregated_v2(ti, r, damon_nr_regions(t));
damon_warn_fix_nr_accesses_corruption(r);
r->last_nr_accesses = r->nr_accesses;
r->nr_accesses = 0;
--
2.47.3