hrtimer: Add hrtimer_rearm tracepoint

Analyzing the reprogramming of the clock event device is essential to debug
the behaviour of the hrtimer subsystem especially with the upcoming
deferred rearming scheme.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260224163430.803669745@kernel.org

include/trace/events/timer.h

@@ -324,6 +324,30 @@ DEFINE_EVENT(hrtimer_class, hrtimer_cancel,
 	TP_ARGS(hrtimer)
 );
 
+/**
+ * hrtimer_rearm - Invoked when the clockevent device is rearmed
+ * @next_event:	The next expiry time (CLOCK_MONOTONIC)
+ */
+TRACE_EVENT(hrtimer_rearm,
+
+	TP_PROTO(ktime_t next_event, bool deferred),
+
+	TP_ARGS(next_event, deferred),
+
+	TP_STRUCT__entry(
+		__field( s64,		next_event	)
+		__field( bool,		deferred	)
+	),
+
+	TP_fast_assign(
+		__entry->next_event	= next_event;
+		__entry->deferred	= deferred;
+	),
+
+	TP_printk("next_event=%llu deferred=%d",
+		  (unsigned long long) __entry->next_event, __entry->deferred)
+);
+
 /**
  * itimer_state - called when itimer is started or canceled
  * @which:	name of the interval timer