Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751823AbdDMFRY (ORCPT ); Thu, 13 Apr 2017 01:17:24 -0400 Received: from lelnx193.ext.ti.com ([198.47.27.77]:29966 "EHLO lelnx193.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751375AbdDMFRW (ORCPT ); Thu, 13 Apr 2017 01:17:22 -0400 Subject: Re: [PATCH] thermal: core: Allow orderly_poweroff to be called only once To: Eduardo Valentin References: <1491988332-13398-1-git-send-email-j-keerthy@ti.com> <20170413050637.GA7816@localhost.localdomain> CC: , , , , , From: Keerthy Message-ID: Date: Thu, 13 Apr 2017 10:47:14 +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: <20170413050637.GA7816@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: 2804 Lines: 82 On Thursday 13 April 2017 10:36 AM, Eduardo Valentin wrote: > Hey, > > On Wed, Apr 12, 2017 at 02:42:12PM +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. >> >> Fixes: 0c01ebbfd3caf1d ("Thermal: Remove throttling logic out of thermal_sys.c") > > Why? how the above commit introduced this issue? git blame showed me that. I can remove this. Let me know if you have the right commit that introduced this. > >> Reported-by: Nishanth Menon >> Signed-off-by: Keerthy >> --- >> drivers/thermal/thermal_core.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c >> index 11f0675..4e68ce0 100644 >> --- a/drivers/thermal/thermal_core.c >> +++ b/drivers/thermal/thermal_core.c >> @@ -326,6 +326,7 @@ 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; >> > > I am not convinced this change does what you say it does.. > >> tz->ops->get_trip_temp(tz, trip, &trip_temp); >> >> @@ -338,11 +339,12 @@ 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); >> orderly_poweroff(true); > > Imagine you have two zones about to enter critical path. thermal zone 0 > first gets into critical, and at this line (btween orderly_poweroff() > and you set your flag), it gets preempted. Then thermal zone 1 also > enters the critical path, then happens to be scheduled, you essentially > end up still calling orderly_poweroff() twice, which is what this patch > is supposed to avoid. > > You better simply use a lock to serialize code execution. Okay understood. Will do it in the next version. > > BR, > >> + power_off_triggered = true; >> } >> } >> >> -- >> 1.9.1 >>