diff mbox series

watchdog: Add tracing events for the most usual watchdog events

Message ID 20220930144935.3373366-1-u.kleine-koenig@pengutronix.de (mailing list archive)
State Superseded
Headers show
Series watchdog: Add tracing events for the most usual watchdog events | expand

Commit Message

Uwe Kleine-König Sept. 30, 2022, 2:49 p.m. UTC 
To simplify debugging which process touches a watchdog and when, add
tracing events for .start(), .set_timeout(), .ping() and .stop().

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 MAINTAINERS                      |  1 +
 drivers/watchdog/watchdog_core.c |  4 ++
 drivers/watchdog/watchdog_dev.c  | 12 ++++-
 include/trace/events/watchdog.h  | 92 ++++++++++++++++++++++++++++++++
 4 files changed, 107 insertions(+), 2 deletions(-)
 create mode 100644 include/trace/events/watchdog.h


base-commit: 568035b01cfb107af8d2e4bd2fb9aea22cf5b868

Comments

Steven Rostedt Oct. 3, 2022, 4:29 p.m. UTC | #1 
On Fri, 30 Sep 2022 16:49:35 +0200
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:


> --- /dev/null
> +++ b/include/trace/events/watchdog.h
> @@ -0,0 +1,92 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM watchdog
> +
> +#if !defined(_TRACE_WATCHDOG_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_WATCHDOG_H
> +
> +#include <linux/watchdog.h>
> +#include <linux/tracepoint.h>
> +
> +TRACE_EVENT(watchdog_start,
> +
> +	TP_PROTO(struct watchdog_device *wdd, int err),
> +
> +	TP_ARGS(wdd, err),
> +
> +	TP_STRUCT__entry(
> +		__field(int, id)
> +		__field(int, err)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->id = wdd->id;
> +		__entry->err = err;
> +	),
> +
> +	TP_printk("watchdog%d err=%d", __entry->id, __entry->err)
> +);
> +

[..]

> +
> +TRACE_EVENT(watchdog_ping,
> +
> +	TP_PROTO(struct watchdog_device *wdd, int err),
> +
> +	TP_ARGS(wdd, err),
> +
> +	TP_STRUCT__entry(
> +		__field(int, id)
> +		__field(int, err)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->id = wdd->id;
> +		__entry->err = err;
> +	),
> +
> +	TP_printk("watchdog%d err=%d", __entry->id, __entry->err)
> +);
> +
> +TRACE_EVENT(watchdog_stop,
> +
> +	TP_PROTO(struct watchdog_device *wdd, int err),
> +
> +	TP_ARGS(wdd, err),
> +
> +	TP_STRUCT__entry(
> +		__field(int, id)
> +		__field(int, err)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->id = wdd->id;
> +		__entry->err = err;
> +	),
> +
> +	TP_printk("watchdog%d err=%d", __entry->id, __entry->err)
> +);

These three events are identical. Please replace them with:

DECLARE_EVENT_CLASS(watchdog_template,

	TP_PROTO(struct watchdog_device *wdd, int err),

	TP_ARGS(wdd, err),

	TP_STRUCT__entry(
		__field(int, id)
		__field(int, err)
	),

	TP_fast_assign(
		__entry->id = wdd->id;
		__entry->err = err;
	),

	TP_printk("watchdog%d err=%d", __entry->id, __entry->err)
);

DEFINE_EVENT(watchdog_template, watchdog_start,
	TP_PROTO(struct watchdog_device *wdd, int err),
	TP_ARGS(wdd, err));

DEFINE_EVENT(watchdog_template, watchdog_ping,
	TP_PROTO(struct watchdog_device *wdd, int err),
	TP_ARGS(wdd, err));

DEFINE_EVENT(watchdog_template, watchdog_stop,
	TP_PROTO(struct watchdog_device *wdd, int err),
	TP_ARGS(wdd, err));


Each TRACE_EVENT() is defined as
  DECLARE_EVENT_CLASS(..)
  DEFINE_EVENT(..)

Where the DECLARE_EVENT_CLASS takes up most of the memory (5KB worth), and
each DEFINE_EVENT() takes up just around 500 bytes to implement.

Using multiple DEFINE_EVENTS() can save 10KB from the above.

-- Steve


> +
> +#endif /* !defined(_TRACE_WATCHDOG_H) || defined(TRACE_HEADER_MULTI_READ) */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
> 
> base-commit: 568035b01cfb107af8d2e4bd2fb9aea22cf5b868
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 8a5012ba6ff9..505b9f4843bd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21860,6 +21860,7 @@  F:	Documentation/watchdog/
 F:	drivers/watchdog/
 F:	include/linux/watchdog.h
 F:	include/uapi/linux/watchdog.h
+F:	include/trace/events/watchdog.h
 
 WHISKEYCOVE PMIC GPIO DRIVER
 M:	Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 3fe8a7edc252..c777a612d932 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -38,6 +38,9 @@ 
 
 #include "watchdog_core.h"	/* For watchdog_dev_register/... */
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/watchdog.h>
+
 static DEFINE_IDA(watchdog_ida);
 
 static int stop_on_reboot = -1;
@@ -163,6 +166,7 @@  static int watchdog_reboot_notifier(struct notifier_block *nb,
 			int ret;
 
 			ret = wdd->ops->stop(wdd);
+			trace_watchdog_stop(wdd, ret);
 			if (ret)
 				return NOTIFY_BAD;
 		}
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 54903f3c851e..3323309c913c 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -47,6 +47,8 @@ 
 #include "watchdog_core.h"
 #include "watchdog_pretimeout.h"
 
+#include <trace/events/watchdog.h>
+
 /* the dev_t structure to store the dynamically allocated watchdog devices */
 static dev_t watchdog_devt;
 /* Reference to watchdog device behind /dev/watchdog */
@@ -157,10 +159,13 @@  static int __watchdog_ping(struct watchdog_device *wdd)
 
 	wd_data->last_hw_keepalive = now;
 
-	if (wdd->ops->ping)
+	if (wdd->ops->ping) {
 		err = wdd->ops->ping(wdd);  /* ping the watchdog */
-	else
+		trace_watchdog_ping(wdd, err);
+	} else {
 		err = wdd->ops->start(wdd); /* restart watchdog */
+		trace_watchdog_start(wdd, err);
+	}
 
 	if (err == 0)
 		watchdog_hrtimer_pretimeout_start(wdd);
@@ -259,6 +264,7 @@  static int watchdog_start(struct watchdog_device *wdd)
 		}
 	} else {
 		err = wdd->ops->start(wdd);
+		trace_watchdog_start(wdd, err);
 		if (err == 0) {
 			set_bit(WDOG_ACTIVE, &wdd->status);
 			wd_data->last_keepalive = started_at;
@@ -297,6 +303,7 @@  static int watchdog_stop(struct watchdog_device *wdd)
 	if (wdd->ops->stop) {
 		clear_bit(WDOG_HW_RUNNING, &wdd->status);
 		err = wdd->ops->stop(wdd);
+		trace_watchdog_stop(wdd, err);
 	} else {
 		set_bit(WDOG_HW_RUNNING, &wdd->status);
 	}
@@ -369,6 +376,7 @@  static int watchdog_set_timeout(struct watchdog_device *wdd,
 
 	if (wdd->ops->set_timeout) {
 		err = wdd->ops->set_timeout(wdd, timeout);
+		trace_watchdog_set_timeout(wdd, timeout, err);
 	} else {
 		wdd->timeout = timeout;
 		/* Disable pretimeout if it doesn't fit the new timeout */
diff --git a/include/trace/events/watchdog.h b/include/trace/events/watchdog.h
new file mode 100644
index 000000000000..b465353fe88f
--- /dev/null
+++ b/include/trace/events/watchdog.h
@@ -0,0 +1,92 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM watchdog
+
+#if !defined(_TRACE_WATCHDOG_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_WATCHDOG_H
+
+#include <linux/watchdog.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(watchdog_start,
+
+	TP_PROTO(struct watchdog_device *wdd, int err),
+
+	TP_ARGS(wdd, err),
+
+	TP_STRUCT__entry(
+		__field(int, id)
+		__field(int, err)
+	),
+
+	TP_fast_assign(
+		__entry->id = wdd->id;
+		__entry->err = err;
+	),
+
+	TP_printk("watchdog%d err=%d", __entry->id, __entry->err)
+);
+
+TRACE_EVENT(watchdog_set_timeout,
+
+	TP_PROTO(struct watchdog_device *wdd, unsigned int timeout, int err),
+
+	TP_ARGS(wdd, timeout, err),
+
+	TP_STRUCT__entry(
+		__field(int, id)
+		__field(unsigned int, timeout)
+		__field(int, err)
+	),
+
+	TP_fast_assign(
+		__entry->id = wdd->id;
+		__entry->timeout = timeout;
+		__entry->err = err;
+	),
+
+	TP_printk("watchdog%d timeout=%u err=%d", __entry->id, __entry->timeout, __entry->err)
+);
+
+TRACE_EVENT(watchdog_ping,
+
+	TP_PROTO(struct watchdog_device *wdd, int err),
+
+	TP_ARGS(wdd, err),
+
+	TP_STRUCT__entry(
+		__field(int, id)
+		__field(int, err)
+	),
+
+	TP_fast_assign(
+		__entry->id = wdd->id;
+		__entry->err = err;
+	),
+
+	TP_printk("watchdog%d err=%d", __entry->id, __entry->err)
+);
+
+TRACE_EVENT(watchdog_stop,
+
+	TP_PROTO(struct watchdog_device *wdd, int err),
+
+	TP_ARGS(wdd, err),
+
+	TP_STRUCT__entry(
+		__field(int, id)
+		__field(int, err)
+	),
+
+	TP_fast_assign(
+		__entry->id = wdd->id;
+		__entry->err = err;
+	),
+
+	TP_printk("watchdog%d err=%d", __entry->id, __entry->err)
+);
+
+#endif /* !defined(_TRACE_WATCHDOG_H) || defined(TRACE_HEADER_MULTI_READ) */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>