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From:   Junwen Wu <wudaemon@163.com>
To:     rostedt@goodmis.org, mingo@redhat.com, tglx@linutronix.de,
        frederic@kernel.org, tannerlove@google.com, wudaemon@163.com
Cc:     linux-kernel@vger.kernel.org
Subject: [PATCH v1] softirq: Add tracepoint for tasklet_entry/exit
Date:   Sun,  8 May 2022 16:06:24 +0000
Message-Id: <20220508160624.48643-1-wudaemon@163.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Usually softirq handler is pre-defined,only tasklet can be register by
driver.We expand tracepoint for tasklet_entry/exit to trace
tasklet handler.

Signed-off-by: Junwen Wu <wudaemon@163.com>
---
 include/trace/events/irq.h | 32 ++++++++++++++++++++++++++++++++
 kernel/softirq.c           |  4 ++++
 2 files changed, 36 insertions(+)

diff --git a/include/trace/events/irq.h b/include/trace/events/irq.h
index eeceafaaea4c..d3e922dcd475 100644
--- a/include/trace/events/irq.h
+++ b/include/trace/events/irq.h
@@ -160,6 +160,38 @@ DEFINE_EVENT(softirq, softirq_raise,
 	TP_ARGS(vec_nr)
 );
 
+TRACE_EVENT(tasklet_entry,
+
+	TP_PROTO(void *func),
+
+	TP_ARGS(func),
+
+	TP_STRUCT__entry(
+		__field(        void *,    func          )
+	),
+
+	TP_fast_assign(
+	__entry->func = func;
+	),
+
+	TP_printk("function=%ps", __entry->func)
+);
+TRACE_EVENT(tasklet_exit,
+
+	TP_PROTO(void *func),
+
+	TP_ARGS(func),
+
+	TP_STRUCT__entry(
+		__field(        void *,    func          )
+	),
+
+	TP_fast_assign(
+		__entry->func = func;
+	),
+
+	TP_printk("function=%ps", __entry->func)
+);
 #endif /*  _TRACE_IRQ_H */
 
 /* This part must be outside protection */
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 41f470929e99..b3bce2b3b655 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -780,10 +780,14 @@ static void tasklet_action_common(struct softirq_action *a,
 		if (tasklet_trylock(t)) {
 			if (!atomic_read(&t->count)) {
 				if (tasklet_clear_sched(t)) {
+					trace_tasklet_entry(t->use_callback ? (void *)t->callback 
+							: (void *)t->func);
 					if (t->use_callback)
 						t->callback(t);
 					else
 						t->func(t->data);
+					trace_tasklet_exit(t->use_callback ? (void *)t->callback
+							: (void *)t->func);
 				}
 				tasklet_unlock(t);
 				continue;
-- 
2.25.1