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path: root/drivers/thermal/power_allocator.c
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2016-08-08thermal: fix race condition when updating cooling deviceMichele Di Giorgio
When multiple thermal zones are bound to the same cooling device, multiple kernel threads may want to update the cooling device state by calling thermal_cdev_update(). Having cdev not protected by a mutex can lead to a race condition. Consider the following situation with two kernel threads k1 and k2: Thread k1 Thread k2 || || call thermal_cdev_update() || ... || set_cur_state(cdev, target); call power_actor_set_power() || ... || instance->target = state; || cdev->updated = false; || || cdev->updated = true; || // completes execution call thermal_cdev_update() || // cdev->updated == true || return; || \/ time k2 has already looped through the thermal instances looking for the deepest cooling device state and is preempted right before setting cdev->updated to true. Now, k1 runs, modifies the thermal instance state and sets cdev->updated to false. Then, k1 is preempted and k2 continues the execution by setting cdev->updated to true, therefore preventing k1 from performing the update. Notice that this is not an issue if k2 looks at the instance->target modified by k1 "after" it is assigned by k1. In fact, in this case the update will happen anyway and k1 can safely return immediately from thermal_cdev_update(). This may lead to a situation where a thermal governor never updates the cooling device. For example, this is the case for the step_wise governor: when calling the function thermal_zone_trip_update(), the governor may always get a new state equal to the old one (which, however, wasn't notified to the cooling device) and will therefore skip the update. CC: Zhang Rui <rui.zhang@intel.com> CC: Eduardo Valentin <edubezval@gmail.com> CC: Peter Feuerer <peter@piie.net> Reported-by: Toby Huang <toby.huang@arm.com> Signed-off-by: Michele Di Giorgio <michele.digiorgio@arm.com> Reviewed-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2016-04-20thermal: power_allocator: req_range multiplication should be a 64 bit typeJavi Merino
req_range is declared as a u64 to cope with overflows in the multiplication of two u32. As both req_power and power_range are u32, we need to make sure the multiplication is done with u64 types. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-11-12thermal: power_allocator: Use temperature reading from tzKapileshwar Singh
All thermal governors use the temperature value stored in struct thermal_zone_device. thermal_zone_device->temperature power_allocator governor should not deviate from this and use the same. Cc: Javi Merino <javi.merino@arm.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: Daniel Kurtz <djkurtz@chromium.org> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Javi Merino <javi.merino@arm.com> Reported-by: Sugumar Natarajan <sugumar.natarajan@arm.com> Signed-off-by: Kapileshwar Singh <kapileshwar.singh@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-11-09remove abs64()Andrew Morton
Switch everything to the new and more capable implementation of abs(). Mainly to give the new abs() a bit of a workout. Cc: Michal Nazarewicz <mina86@mina86.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-01thermal: avoid division by zero in power allocatorAndrea Arcangeli
During boot I get a div by zero Oops regression starting in v4.3-rc3. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Javi Merino <javi.merino@arm.com> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: Daniel Kurtz <djkurtz@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-20thermal: power_allocator: exit early if there are no cooling devicesJavi Merino
Don't waste cycles in the power allocator governor's throttle function if there are no cooling devices and exit early. This commit doesn't change any functionality, but should provide better performance for the odd case of a thermal zone with trip points but without cooling devices. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-09-14thermal: power_allocator: don't require tzp to be present for the thermal zoneJavi Merino
Thermal zones created using thermal_zone_device_create() may not have tzp. As the governor gets its parameters from there, allocate it while the governor is bound to the thermal zone so that it can operate in it. In this case, tzp is freed when the thermal zone switches to another governor. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-09-14thermal: power_allocator: relax the requirement of two passive trip pointsJavi Merino
The power allocator governor currently requires that the thermal zone has at least two passive trip points. If there aren't, the governor refuses to bind to the thermal zone. This commit relaxes that requirement. Now the governor will bind to all thermal zones regardless of how many trip points they have. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-09-14thermal: power_allocator: relax the requirement of a sustainable_power in tzpJavi Merino
The power allocator governor currently requires that a sustainable power is passed as part of the thermal zone's thermal zone parameters. If that parameter is not provided, it doesn't register with the thermal zone. While this parameter is strongly recommended for optimal performance, it doesn't need to be mandatory. Relax the requirement and allow the governor to bind to thermal zones that don't provide it by estimating it from the cooling devices' power model. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-09-02Merge branches 'thermal-core' and 'thermal-intel' of .git into nextZhang Rui
2015-08-29thermal: power_allocator: allocate with kcalloc what you free with kfreeJavi Merino
Commit cf736ea6f902 ("thermal: power_allocator: do not use devm* interfaces") forgot to change a devm_kcalloc() to just kcalloc(), but it's corresponding devm_kfree() was changed to kfree(). Allocate with kcalloc() to match the kfree(). Fixes: cf736ea6f902 ("thermal: power_allocator: do not use devm* interfaces") Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-08-13thermal: power_allocator: do not use devm* interfacesDmitry Torokhov
The code in question is called outside of standard driver probe()/remove() callbacks and thus will not benefit from use of devm* infrastructure. Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-08-03thermal: consistently use int for temperaturesSascha Hauer
The thermal code uses int, long and unsigned long for temperatures in different places. Using an unsigned type limits the thermal framework to positive temperatures without need. Also several drivers currently will report temperatures near UINT_MAX for temperatures below 0°C. This will probably immediately shut the machine down due to overtemperature if started below 0°C. 'long' is 64bit on several architectures. This is not needed since INT_MAX °mC is above the melting point of all known materials. Consistently use a plain 'int' for temperatures throughout the thermal code and the drivers. This only changes the places in the drivers where the temperature is passed around as pointer, when drivers internally use another type this is not changed. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Jean Delvare <jdelvare@suse.de> Reviewed-by: Lukasz Majewski <l.majewski@samsung.com> Reviewed-by: Darren Hart <dvhart@linux.intel.com> Reviewed-by: Heiko Stuebner <heiko@sntech.de> Reviewed-by: Peter Feuerer <peter@piie.net> Cc: Punit Agrawal <punit.agrawal@arm.com> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Jean Delvare <jdelvare@suse.de> Cc: Peter Feuerer <peter@piie.net> Cc: Heiko Stuebner <heiko@sntech.de> Cc: Lukasz Majewski <l.majewski@samsung.com> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: linux-acpi@vger.kernel.org Cc: platform-driver-x86@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-omap@vger.kernel.org Cc: linux-samsung-soc@vger.kernel.org Cc: Guenter Roeck <linux@roeck-us.net> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Maxime Ripard <maxime.ripard@free-electrons.com> Cc: Darren Hart <dvhart@infradead.org> Cc: lm-sensors@lm-sensors.org Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2015-08-02thermal: power_allocator: trace the real requested powerJavi Merino
The power allocator governor uses ftrace to output a bunch of internal data for debugging and tuning. Currently, the requested power it outputs is the "weighted" requested power, that is, what each cooling device has requested multiplied by the cooling device weight. It is more useful to trace the real request, without any weight being applied. This commit only affects the data traced, there is no functional change. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-05-11thermal: power_allocator: round the division when divvying up powerJavi Merino
In situations where there is an uneven number of cooling devices, the division of power among them can lead to a milliwatt being dropped on the floor due to rounding errors. This doesn't sound like a lot, but some devices only grant the lowest cooling device state for their maximum power. So for instance, if the granted_power is the maximum power and all devices are getting their maximum power, one would get max_power - 1, making it choose cooling device state 1, instead of 0. Round the division to make the calculation more accurate. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-05-04thermal: add trace events to the power allocator governorJavi Merino
Add trace events for the power allocator governor and the power actor interface of the cpu cooling device. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-05-04thermal: introduce the Power Allocator governorJavi Merino
The power allocator governor is a thermal governor that controls system and device power allocation to control temperature. Conceptually, the implementation divides the sustainable power of a thermal zone among all the heat sources in that zone. This governor relies on "power actors", entities that represent heat sources. They can report current and maximum power consumption and can set a given maximum power consumption, usually via a cooling device. The governor uses a Proportional Integral Derivative (PID) controller driven by the temperature of the thermal zone. The output of the controller is a power budget that is then allocated to each power actor that can have bearing on the temperature we are trying to control. It decides how much power to give each cooling device based on the performance they are requesting. The PID controller ensures that the total power budget does not exceed the control temperature. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>