From: SeongJae Park <redacted>

This commit adds a tracepoint for DAMON.  It traces the monitoring
results of each region for each aggregation interval.  Using this, DAMON
will be easily integrated with any tracepoints supporting tools such as
perf.

Signed-off-by: SeongJae Park <redacted>
Reviewed-by: Leonard Foerster <redacted>
---
 include/trace/events/damon.h | 43 ++++++++++++++++++++++++++++++++++++
 mm/damon.c                   |  5 +++++
 2 files changed, 48 insertions(+)
 create mode 100644 include/trace/events/damon.h

diff --git a/include/trace/events/damon.h b/include/trace/events/damon.h
new file mode 100644
index 000000000000..22236642d366
--- /dev/null
+++ b/include/trace/events/damon.h

@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM damon
+
+#if !defined(_TRACE_DAMON_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_DAMON_H
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(damon_aggregated,
+
+	TP_PROTO(int pid, unsigned int nr_regions,
+		unsigned long vm_start, unsigned long vm_end,
+		unsigned int nr_accesses),
+
+	TP_ARGS(pid, nr_regions, vm_start, vm_end, nr_accesses),
+
+	TP_STRUCT__entry(
+		__field(int, pid)
+		__field(unsigned int, nr_regions)
+		__field(unsigned long, vm_start)
+		__field(unsigned long, vm_end)
+		__field(unsigned int, nr_accesses)
+	),
+
+	TP_fast_assign(
+		__entry->pid = pid;
+		__entry->nr_regions = nr_regions;
+		__entry->vm_start = vm_start;
+		__entry->vm_end = vm_end;
+		__entry->nr_accesses = nr_accesses;
+	),
+
+	TP_printk("pid=%d nr_regions=%u %lu-%lu: %u", __entry->pid,
+			__entry->nr_regions, __entry->vm_start,
+			__entry->vm_end, __entry->nr_accesses)
+);
+
+#endif /* _TRACE_DAMON_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

diff --git a/mm/damon.c b/mm/damon.c
index 6b0b8f21a6c6..af6f395fe06c 100644
--- a/mm/damon.c
+++ b/mm/damon.c

@@ -9,6 +9,8 @@
 
 #define pr_fmt(fmt) "damon: " fmt
 
+#define CREATE_TRACE_POINTS
+
 #include <linux/damon.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>

@@ -20,6 +22,7 @@
 #include <linux/sched/mm.h>
 #include <linux/sched/task.h>
 #include <linux/slab.h>
+#include <trace/events/damon.h>
 
 /* Minimal region size.  Every damon_region is aligned by this. */
 #define MIN_REGION PAGE_SIZE

@@ -650,6 +653,8 @@ static void kdamond_reset_aggregated(struct damon_ctx *c)
 			damon_write_rbuf(c, &r->vm_end, sizeof(r->vm_end));
 			damon_write_rbuf(c, &r->nr_accesses,
 					sizeof(r->nr_accesses));
+			trace_damon_aggregated(t->pid, nr,
+					r->vm_start, r->vm_end, r->nr_accesses);