On 6/16/22 15:44, Guenter Roeck wrote:
> On 6/16/22 01:44, Daniel Bristot de Oliveira wrote:
>> Add a set of tracepoints, enabling the observability of the watchdog
>> device interactions with user-space.
>>
>> The events are:
>> watchdog:watchdog_open
>> watchdog:watchdog_close
>> watchdog:watchdog_start
>> watchdog:watchdog_stop
>> watchdog:watchdog_set_timeout
>> watchdog:watchdog_ping
>> watchdog:watchdog_nowayout
>> watchdog:watchdog_set_keep_alive
>> watchdog:watchdog_keep_alive
>> watchdog:watchdog_set_pretimeout
>> watchdog:watchdog_pretimeout
>>
>> Cc: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>
>> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
>> Cc: Jonathan Corbet <corbet@xxxxxxx>
>> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>> Cc: Will Deacon <will@xxxxxxxxxx>
>> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
>> Cc: Marco Elver <elver@xxxxxxxxxx>
>> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
>> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
>> Cc: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
>> Cc: Gabriele Paoloni <gpaoloni@xxxxxxxxxx>
>> Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
>> Cc: Clark Williams <williams@xxxxxxxxxx>
>> Cc: linux-doc@xxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Cc: linux-trace-devel@xxxxxxxxxxxxxxx
>> Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
>> ---
>> drivers/watchdog/watchdog_dev.c | 43 ++++++++++-
>> drivers/watchdog/watchdog_pretimeout.c | 2 +
>> include/linux/watchdog.h | 7 +-
>> include/trace/events/watchdog.h | 101 +++++++++++++++++++++++++
>> 4 files changed, 143 insertions(+), 10 deletions(-)
>> create mode 100644 include/trace/events/watchdog.h
>>
>> diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
>> index 54903f3c851e..2f28dc5ab763 100644
>> --- a/drivers/watchdog/watchdog_dev.c
>> +++ b/drivers/watchdog/watchdog_dev.c
>> @@ -44,6 +44,9 @@
>> #include <linux/watchdog.h> /* For watchdog specific items */
>> #include <linux/uaccess.h> /* For copy_to_user/put_user/... */
>> +#define CREATE_TRACE_POINTS
>> +#include <trace/events/watchdog.h>
>> +
>> #include "watchdog_core.h"
>> #include "watchdog_pretimeout.h"
>> @@ -130,9 +133,11 @@ static inline void watchdog_update_worker(struct
>> watchdog_device *wdd)
>> if (watchdog_need_worker(wdd)) {
>> ktime_t t = watchdog_next_keepalive(wdd);
>> - if (t > 0)
>> + if (t > 0) {
>> hrtimer_start(&wd_data->timer, t,
>> HRTIMER_MODE_REL_HARD);
>> + trace_watchdog_set_keep_alive(wdd, ktime_to_ms(t));
>> + }
>> } else {
>> hrtimer_cancel(&wd_data->timer);
>> }
>> @@ -141,7 +146,7 @@ static inline void watchdog_update_worker(struct
>> watchdog_device *wdd)
>> static int __watchdog_ping(struct watchdog_device *wdd)
>> {
>> struct watchdog_core_data *wd_data = wdd->wd_data;
>> - ktime_t earliest_keepalive, now;
>> + ktime_t earliest_keepalive, now, next_keepalive;
>> int err;
>> earliest_keepalive = ktime_add(wd_data->last_hw_keepalive,
>> @@ -149,14 +154,16 @@ static int __watchdog_ping(struct watchdog_device *wdd)
>> now = ktime_get();
>> if (ktime_after(earliest_keepalive, now)) {
>> - hrtimer_start(&wd_data->timer,
>> - ktime_sub(earliest_keepalive, now),
>> + next_keepalive = ktime_sub(earliest_keepalive, now);
>> + hrtimer_start(&wd_data->timer, next_keepalive,
>> HRTIMER_MODE_REL_HARD);
>> + trace_watchdog_set_keep_alive(wdd, ktime_to_ms(next_keepalive));
>> return 0;
>> }
>> wd_data->last_hw_keepalive = now;
>> + trace_watchdog_ping(wdd);
>> if (wdd->ops->ping)
>> err = wdd->ops->ping(wdd); /* ping the watchdog */
>> else
>> @@ -215,6 +222,7 @@ static void watchdog_ping_work(struct kthread_work *work)
>> wd_data = container_of(work, struct watchdog_core_data, work);
>> mutex_lock(&wd_data->lock);
>> + trace_watchdog_keep_alive(wd_data->wdd);
>> if (watchdog_worker_should_ping(wd_data))
>> __watchdog_ping(wd_data->wdd);
>> mutex_unlock(&wd_data->lock);
>> @@ -250,6 +258,8 @@ static int watchdog_start(struct watchdog_device *wdd)
>> set_bit(_WDOG_KEEPALIVE, &wd_data->status);
>> + trace_watchdog_start(wdd);
>> +
>> started_at = ktime_get();
>> if (watchdog_hw_running(wdd) && wdd->ops->ping) {
>> err = __watchdog_ping(wdd);
>> @@ -294,6 +304,7 @@ static int watchdog_stop(struct watchdog_device *wdd)
>> return -EBUSY;
>> }
>> + trace_watchdog_stop(wdd);
>> if (wdd->ops->stop) {
>> clear_bit(WDOG_HW_RUNNING, &wdd->status);
>> err = wdd->ops->stop(wdd);
>> @@ -367,6 +378,7 @@ static int watchdog_set_timeout(struct watchdog_device *wdd,
>> if (watchdog_timeout_invalid(wdd, timeout))
>> return -EINVAL;
>> + trace_watchdog_set_timeout(wdd, timeout);
>
> The driver has no obligation to set the timeout to the
> requested value. It might be more valuable to report both
> the requested and the actual values.
>
>
Ack! how do I get the actual value?
>> if (wdd->ops->set_timeout) {
>> err = wdd->ops->set_timeout(wdd, timeout);
>> } else {
>> @@ -399,6 +411,8 @@ static int watchdog_set_pretimeout(struct watchdog_device
>> *wdd,
>> if (watchdog_pretimeout_invalid(wdd, timeout))
>> return -EINVAL;
>> + trace_watchdog_set_pretimeout(wdd, timeout);
>> +
>
> Again, the driver has no obligation to set the timeout to the
> requested value.
/me takes note.
>
>> if (wdd->ops->set_pretimeout && (wdd->info->options & WDIOF_PRETIMEOUT))
>> err = wdd->ops->set_pretimeout(wdd, timeout);
>> else
>> @@ -430,6 +444,23 @@ static int watchdog_get_timeleft(struct watchdog_device
>> *wdd,
>> return 0;
>> }
>> +/**
>> + * watchdog_set_nowayout - set nowaout bit
>> + * @wdd: The watchdog device to set nowayoutbit
>> + * @nowayout A boolean on/off switcher
>> + *
>> + * If nowayout boolean is true, the nowayout option is set. No action is
>> + * taken if nowayout is false.
>> + */
>> +void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
>> +{
>> + if (nowayout) {
>> + set_bit(WDOG_NO_WAY_OUT, &wdd->status);
>> + trace_watchdog_nowayout(wdd);
>> + }
>> +}
>> +EXPORT_SYMBOL(watchdog_set_nowayout);
>> +
>> #ifdef CONFIG_WATCHDOG_SYSFS
>> static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr,
>> char *buf)
>> @@ -861,6 +892,8 @@ static int watchdog_open(struct inode *inode, struct file
>> *file)
>> goto out_clear;
>> }
>> + trace_watchdog_open(wdd);
>> +
>> err = watchdog_start(wdd);
>> if (err < 0)
>> goto out_mod;
>> @@ -883,6 +916,7 @@ static int watchdog_open(struct inode *inode, struct file
>> *file)
>> return stream_open(inode, file);
>> out_mod:
>> + trace_watchdog_close(wdd);
>> module_put(wd_data->wdd->ops->owner);
>> out_clear:
>> clear_bit(_WDOG_DEV_OPEN, &wd_data->status);
>> @@ -944,6 +978,7 @@ static int watchdog_release(struct inode *inode, struct
>> file *file)
>> /* make sure that /dev/watchdog can be re-opened */
>> clear_bit(_WDOG_DEV_OPEN, &wd_data->status);
>> + trace_watchdog_close(wdd);
>> done:
>> running = wdd && watchdog_hw_running(wdd);
>> mutex_unlock(&wd_data->lock);
>> diff --git a/drivers/watchdog/watchdog_pretimeout.c
>> b/drivers/watchdog/watchdog_pretimeout.c
>> index 376a495ab80c..58c391ed2205 100644
>> --- a/drivers/watchdog/watchdog_pretimeout.c
>> +++ b/drivers/watchdog/watchdog_pretimeout.c
>> @@ -8,6 +8,7 @@
>> #include <linux/spinlock.h>
>> #include <linux/string.h>
>> #include <linux/watchdog.h>
>> +#include <trace/events/watchdog.h>
>> #include "watchdog_core.h"
>> #include "watchdog_pretimeout.h"
>> @@ -107,6 +108,7 @@ void watchdog_notify_pretimeout(struct watchdog_device *wdd)
>> return;
>> }
>> + trace_watchdog_pretimeout(wdd);
>> wdd->gov->pretimeout(wdd);
>> spin_unlock_irqrestore(&pretimeout_lock, flags);
>> }
>> diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
>> index 99660197a36c..11d93407e492 100644
>> --- a/include/linux/watchdog.h
>> +++ b/include/linux/watchdog.h
>> @@ -139,12 +139,7 @@ static inline bool watchdog_hw_running(struct
>> watchdog_device *wdd)
>> return test_bit(WDOG_HW_RUNNING, &wdd->status);
>> }
>> -/* Use the following function to set the nowayout feature */
>> -static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool
>> nowayout)
>> -{
>> - if (nowayout)
>> - set_bit(WDOG_NO_WAY_OUT, &wdd->status);
>> -}
>> +void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout);
>> /* Use the following function to stop the watchdog on reboot */
>> static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
>> diff --git a/include/trace/events/watchdog.h b/include/trace/events/watchdog.h
>> new file mode 100644
>> index 000000000000..145cd6cfaa02
>> --- /dev/null
>> +++ b/include/trace/events/watchdog.h
>> @@ -0,0 +1,101 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +#undef TRACE_SYSTEM
>> +#define TRACE_SYSTEM watchdog
>> +
>> +#if !defined(_TRACE_WATCHDOG_H) || defined(TRACE_HEADER_MULTI_READ)
>> +#define _TRACE_WATCHDOG_H
>> +
>> +#include <linux/tracepoint.h>
>> +
>> +/*
>> + * These are all events whose sole argument is the watchdog id.
>> + */
>> +DECLARE_EVENT_CLASS(dev_operations_template,
>> +
>> + TP_PROTO(struct watchdog_device *wdd),
>> +
>> + TP_ARGS(wdd),
>> +
>> + TP_STRUCT__entry(
>> + __field(__u32, id)
>> + ),
>> +
>> + TP_fast_assign(
>> + __entry->id = wdd->id;
>> + ),
>> +
>> + TP_printk("id=%d",
>> + __entry->id)
>> +);
>> +
>> +DEFINE_EVENT(dev_operations_template, watchdog_open,
>> + TP_PROTO(struct watchdog_device *wdd),
>> + TP_ARGS(wdd));
>> +
>> +DEFINE_EVENT(dev_operations_template, watchdog_close,
>> + TP_PROTO(struct watchdog_device *wdd),
>> + TP_ARGS(wdd));
>> +
>> +DEFINE_EVENT(dev_operations_template, watchdog_start,
>> + TP_PROTO(struct watchdog_device *wdd),
>> + TP_ARGS(wdd));
>> +
>> +DEFINE_EVENT(dev_operations_template, watchdog_stop,
>> + TP_PROTO(struct watchdog_device *wdd),
>> + TP_ARGS(wdd));
>> +
>> +DEFINE_EVENT(dev_operations_template, watchdog_ping,
>> + TP_PROTO(struct watchdog_device *wdd),
>> + TP_ARGS(wdd));
>> +
>> +DEFINE_EVENT(dev_operations_template, watchdog_nowayout,
>> + TP_PROTO(struct watchdog_device *wdd),
>> + TP_ARGS(wdd));
>> +
>> +DEFINE_EVENT(dev_operations_template, watchdog_keep_alive,
>> + TP_PROTO(struct watchdog_device *wdd),
>> + TP_ARGS(wdd));
>> +
>> +DEFINE_EVENT(dev_operations_template, watchdog_pretimeout,
>> + TP_PROTO(struct watchdog_device *wdd),
>> + TP_ARGS(wdd));
>> +
>> +/*
>> + * These are all events with a device ID and a given timeout.
>> + */
>> +DECLARE_EVENT_CLASS(watchdog_timeout_template,
>> +
>> + TP_PROTO(struct watchdog_device *wdd, u64 timeout),
>> +
>> + TP_ARGS(wdd, timeout),
>> +
>> + TP_STRUCT__entry(
>> + __field(__u32, id)
>> + __field(__u64, timeout)
>
>
> Why u64 ? timeout is unsigned long.
ack! I will change it. (I am seeing unsigned int, am I missing something?).
Thanks!
-- Daniel
