[PATCH v8 10/15] mm/damon: Add tracepoints

[SeongJae Park]

From: SeongJae Park <sjpark@xxxxxxxxx>

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 <sjpark@xxxxxxxxx>
---
 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..bec3501f2b05
--- /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(unsigned long 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(unsigned long, 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=%lu 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 1712ce8a88a5..eb0dca2c899c 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>
 
 #define damon_get_task_struct(t) \
 	(get_pid_task(find_vpid(t->pid), PIDTYPE_PID))
@@ -654,6 +657,8 @@ 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);
 			r->nr_accesses = 0;
 		}
 	}
-- 
2.17.1