[PATCH 1/2 v2] memcg: add memcg flush tracepoint event

[JP Kobryn <inwardvessel@gmail.com>]

This is a tracepoint event that contains the memcg pointer and information
on whether the flush was forced, skipped, and the number of stats updated.

Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
---
 include/trace/events/memcg.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/include/trace/events/memcg.h b/include/trace/events/memcg.h
index 8667e57816d2..dfe2f51019b4 100644
--- a/include/trace/events/memcg.h
+++ b/include/trace/events/memcg.h
@@ -74,6 +74,31 @@ DEFINE_EVENT(memcg_rstat_events, count_memcg_events,
 	TP_ARGS(memcg, item, val)
 );
 
+TRACE_EVENT(memcg_flush_stats,
+
+	TP_PROTO(struct mem_cgroup *memcg, s64 stats_updates,
+		bool force, bool needs_flush),
+
+	TP_ARGS(memcg, stats_updates, force, needs_flush),
+
+	TP_STRUCT__entry(
+		__field(u64, id)
+		__field(s64, stats_updates)
+		__field(bool, force)
+		__field(bool, needs_flush)
+	),
+
+	TP_fast_assign(
+		__entry->id = cgroup_id(memcg->css.cgroup);
+		__entry->stats_updates = stats_updates;
+		__entry->force = force;
+		__entry->needs_flush = needs_flush;
+	),
+
+	TP_printk("memcg_id=%llu stats_updates=%lld force=%d needs_flush=%d",
+		__entry->id, __entry->stats_updates,
+		__entry->force, __entry->needs_flush)
+);
 
 #endif /* _TRACE_MEMCG_H */
 
-- 
2.47.0