linux-kernel - Re: [PATCH v2 2/8] thermal/debugfs: Do not extend mitigation episodes beyond system resume

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Date: Mon, 10 Jun 2024 13:29:27 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>, Linux PM <linux-pm@...r.kernel.org>, 
	LKML <linux-kernel@...r.kernel.org>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Lukasz Luba <lukasz.luba@....com>
Subject: Re: [PATCH v2 2/8] thermal/debugfs: Do not extend mitigation episodes
 beyond system resume

On Mon, Jun 10, 2024 at 10:28 AM Daniel Lezcano
<daniel.lezcano@...aro.org> wrote:
>
> On 28/05/2024 16:53, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >
> > Because thermal zone handling by the thermal core is started from
> > scratch during resume from system-wide suspend, prevent the debug
> > code from extending mitigation episodes beyond that point by ending
> > the mitigation episode currently in progress, if any, for each thermal
> > zone.
>
> Why it is done at resume time and not at suspend time ?

Because it is related to thermal_zone_device_init() which also runs at
the resume time, so IMV it's better to keep these two pieces together.

Why would it be better to run this during suspend?

> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > ---
> >
> > v1 -> v2: Rebase.
> >
> > ---
> >   drivers/thermal/thermal_core.c    |    1 +
> >   drivers/thermal/thermal_debugfs.c |   36 ++++++++++++++++++++++++++++++++++++
> >   drivers/thermal/thermal_debugfs.h |    2 ++
> >   3 files changed, 39 insertions(+)
> >
> > Index: linux-pm/drivers/thermal/thermal_core.c
> > ===================================================================
> > --- linux-pm.orig/drivers/thermal/thermal_core.c
> > +++ linux-pm/drivers/thermal/thermal_core.c
> > @@ -1641,6 +1641,7 @@ static void thermal_zone_device_resume(s
> >
> >       tz->suspended = false;
> >
> > +     thermal_debug_tz_resume(tz);
> >       thermal_zone_device_init(tz);
> >       __thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
> >
> > Index: linux-pm/drivers/thermal/thermal_debugfs.c
> > ===================================================================
> > --- linux-pm.orig/drivers/thermal/thermal_debugfs.c
> > +++ linux-pm/drivers/thermal/thermal_debugfs.c
> > @@ -926,3 +926,39 @@ void thermal_debug_tz_remove(struct ther
> >       thermal_debugfs_remove_id(thermal_dbg);
> >       kfree(trips_crossed);
> >   }
> > +
> > +void thermal_debug_tz_resume(struct thermal_zone_device *tz)
> > +{
> > +     struct thermal_debugfs *thermal_dbg = tz->debugfs;
> > +     ktime_t now = ktime_get();
> > +     struct tz_debugfs *tz_dbg;
> > +     struct tz_episode *tze;
> > +     int i;
> > +
> > +     if (!thermal_dbg)
> > +             return;
> > +
> > +     mutex_lock(&thermal_dbg->lock);
> > +
> > +     tz_dbg = &thermal_dbg->tz_dbg;
> > +
> > +     if (!tz_dbg->nr_trips)
> > +             goto out;
> > +
> > +     /*
> > +      * A mitigation episode was in progress before the preceding system
> > +      * suspend transition, so close it because the zone handling is starting
> > +      * over from scratch.
> > +      */
> > +     tze = list_first_entry(&tz_dbg->tz_episodes, struct tz_episode, node);
> > +
> > +     for (i = 0; i < tz_dbg->nr_trips; i++)
> > +             tz_episode_close_trip(tze, tz_dbg->trips_crossed[i], now);
> > +
> > +     tze->duration = ktime_sub(now, tze->timestamp);
> > +
> > +     tz_dbg->nr_trips = 0;
> > +
> > +out:
> > +     mutex_unlock(&thermal_dbg->lock);
> > +}
> > Index: linux-pm/drivers/thermal/thermal_debugfs.h
> > ===================================================================
> > --- linux-pm.orig/drivers/thermal/thermal_debugfs.h
> > +++ linux-pm/drivers/thermal/thermal_debugfs.h
> > @@ -7,6 +7,7 @@ void thermal_debug_cdev_remove(struct th
> >   void thermal_debug_cdev_state_update(const struct thermal_cooling_device *cdev, int state);
> >   void thermal_debug_tz_add(struct thermal_zone_device *tz);
> >   void thermal_debug_tz_remove(struct thermal_zone_device *tz);
> > +void thermal_debug_tz_resume(struct thermal_zone_device *tz);
> >   void thermal_debug_tz_trip_up(struct thermal_zone_device *tz,
> >                             const struct thermal_trip *trip);
> >   void thermal_debug_tz_trip_down(struct thermal_zone_device *tz,
> > @@ -20,6 +21,7 @@ static inline void thermal_debug_cdev_st
> >                                                  int state) {}
> >   static inline void thermal_debug_tz_add(struct thermal_zone_device *tz) {}
> >   static inline void thermal_debug_tz_remove(struct thermal_zone_device *tz) {}
> > +static inline void thermal_debug_tz_resume(struct thermal_zone_device *tz) {}
> >   static inline void thermal_debug_tz_trip_up(struct thermal_zone_device *tz,
> >                                           const struct thermal_trip *trip) {};
> >   static inline void thermal_debug_tz_trip_down(struct thermal_zone_device *tz,
> >
> >
> >
>
> --
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