Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754770AbdDMRaz (ORCPT ); Thu, 13 Apr 2017 13:30:55 -0400 Received: from lelnx194.ext.ti.com ([198.47.27.80]:37623 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752537AbdDMRaw (ORCPT ); Thu, 13 Apr 2017 13:30:52 -0400 Subject: Re: [PATCH v2 1/2] thermal: core: Allow orderly_poweroff to be called only once To: Eduardo Valentin References: <1492070556-24660-1-git-send-email-j-keerthy@ti.com> <20170413151558.GA8412@localhost.localdomain> CC: , , , , , From: Keerthy Message-ID: Date: Thu, 13 Apr 2017 23:00:42 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <20170413151558.GA8412@localhost.localdomain> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3900 Lines: 131 On Thursday 13 April 2017 08:46 PM, Eduardo Valentin wrote: > Hey, > > On Thu, Apr 13, 2017 at 01:32:35PM +0530, Keerthy wrote: >> thermal_zone_device_check --> thermal_zone_device_update --> >> handle_thermal_trip --> handle_critical_trips --> orderly_poweroff >> >> The above sequence happens every 250/500 mS based on the configuration. >> The orderly_poweroff function is getting called every 250/500 mS. >> With a full fledged file system it takes at least 5-10 Seconds to >> power off gracefully. >> >> In that period due to the thermal_zone_device_check triggering >> periodically the thermal work queues bombard with >> orderly_poweroff calls multiple times eventually leading to >> failures in gracefully powering off the system. >> >> Make sure that orderly_poweroff is called only once. >> >> Reported-by: Nishanth Menon > > Was this reported by nm or found by you? Okay i found it when i was debugging the problem reported by nm :-). I will fix that. > >> Signed-off-by: Keerthy >> --- >> >> Changes in v2: >> >> * Added a global mutex to serialize poweroff code sequence. >> >> drivers/thermal/thermal_core.c | 9 ++++++++- >> 1 file changed, 8 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c >> index 11f0675..7462ae5 100644 >> --- a/drivers/thermal/thermal_core.c >> +++ b/drivers/thermal/thermal_core.c >> @@ -45,6 +45,7 @@ >> >> static DEFINE_MUTEX(thermal_list_lock); >> static DEFINE_MUTEX(thermal_governor_lock); >> +static DEFINE_MUTEX(poweroff_lock); >> >> static atomic_t in_suspend; >> >> @@ -326,6 +327,7 @@ static void handle_critical_trips(struct thermal_zone_device *tz, >> int trip, enum thermal_trip_type trip_type) >> { >> int trip_temp; >> + static bool power_off_triggered; >> >> tz->ops->get_trip_temp(tz, trip, &trip_temp); >> >> @@ -338,11 +340,14 @@ static void handle_critical_trips(struct thermal_zone_device *tz, >> if (tz->ops->notify) >> tz->ops->notify(tz, trip, trip_type); >> >> - if (trip_type == THERMAL_TRIP_CRITICAL) { >> + if (trip_type == THERMAL_TRIP_CRITICAL && !power_off_triggered) { >> dev_emerg(&tz->device, >> "critical temperature reached(%d C),shutting down\n", >> tz->temperature / 1000); >> + mutex_lock(&poweroff_lock); >> orderly_poweroff(true); >> + power_off_triggered = true; >> + mutex_unlock(&poweroff_lock); > > The above code does not fully prevent orderly_poweroff() to be called > only once, does it? > > - thermal zone 0 goes all the way in the critical path, but gets > preempted between orderly_poweroff(true)l and power_off_triggered = > true;, i.e., preempted right before setting to true, therefore, > power_off_triggered still 0. > - thermal zone 1 also enters critical path, but will sleep at the > power_off_lock, right? > - then thermal zone 0 gets the CPU again, finishes the critical path, > unlocks poweroff_lock. > - thermal zone 1 is unblocked, and call again orderly_poweroff(true); Oh yes! I will fix that if (trip_type == THERMAL_TRIP_CRITICAL) { dev_emerg(&tz->device, "critical temperature reached(%d C),shutting down\n",tz->temperature / 1000); mutex_lock(&poweroff_lock); if (!power_off_triggered) { orderly_poweroff(true); power_off_triggered = true; } mutex_unlock(&poweroff_lock); } The above should take care. > > > > BR, >> } >> } >> >> @@ -1463,6 +1468,7 @@ static int __init thermal_init(void) >> { >> int result; >> >> + mutex_init(&poweroff_lock); >> result = thermal_register_governors(); >> if (result) >> goto error; >> @@ -1497,6 +1503,7 @@ static int __init thermal_init(void) >> ida_destroy(&thermal_cdev_ida); >> mutex_destroy(&thermal_list_lock); >> mutex_destroy(&thermal_governor_lock); >> + mutex_destroy(&poweroff_lock); >> return result; >> } >> >> -- >> 1.9.1 >>