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Add and use a special guard for cooling devices.
This allows quite a few error code paths to be simplified among
other things and brings in code size reduction for a good measure.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/5837621.DvuYhMxLoT@rjwysocki.net
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
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In almost all places where a thermal zone's list of thermal instances
is walked, there is a check to match a specific trip point and it is
walked in vain whenever there are no cooling devices associated with
the given trip.
To address this, store the lists of thermal instances in trip point
descriptors instead of storing them in thermal zones and adjust all
code using those lists accordingly.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/5522726.Sb9uPGUboI@rjwysocki.net
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
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Commit b6846826982b ("thermal: gov_step_wise: Restore passive polling
management") attempted to fix a Step-Wise thermal governor issue
introduced by commit 042a3d80f118 ("thermal: core: Move passive polling
management to the core"), which caused the governor to leave cooling
devices in high states, by partially reverting that commit.
However, this turns out to be insufficient on some systems due to
interactions between the governor code restored by commit b6846826982b
and the passive polling management in the thermal core.
For this reason, revert commit b6846826982b and make the governor set
the target cooling device state to the "lower" one as soon as the zone
temperature falls below the threshold of the trip point corresponding
to the given thermal instance, which means that thermal mitigation is
not necessary any more.
Before this change the "lower" cooling device state would be reached in
steps through the passive polling mechanism which was questionable for
three reasons: (1) cooling device were kept in high states when that was
not necessary (and it could adversely impact performance), (2) it only
worked for thermal zones with nonzero passive_delay_jiffies value, and
(3) passive polling belongs to the core and should not be hijacked by
governors for their internal purposes.
Fixes: b6846826982b ("thermal: gov_step_wise: Restore passive polling management")
Closes: https://lore.kernel.org/linux-pm/6759ce9f-281d-4fcd-bb4c-b784a1cc5f6e@oldschoolsolutions.biz
Reported-by: Jens Glathe <jens.glathe@oldschoolsolutions.biz>
Tested-by: Jens Glathe <jens.glathe@oldschoolsolutions.biz>
Link: https://patch.msgid.link/12464461.O9o76ZdvQC@rjwysocki.net
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Steev Klimaszewski <steev@kali.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
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Consider a thermal zone with one passive trip point, a cooling device
with 3 states (0, 1, 2) bound to it, passive polling enabled (nonzero
passive_delay_jiffies) and no regular polling (polling_delay_jiffies
equal to 0) that is managed by the Step-Wise governor. Suppose that
the initial state of the cooling device is 0 and the zone temperature
is below the trip point to start with.
When the trip point is crossed, tz->passive is incremented by the
thermal core and the governor's .manage() callback is invoked. It
sets 'throttle' to 'true' for the trip in question and
get_target_state() returns 1 for the instance corresponding to the
cooling device (say that 'upper' and 'lower' are set to 2 and 0 for
it, respectively), so its state changes to 1.
Passive polling is still active for the zone, so next time the
temperature is updated, the governor's .manage() callback will be
invoked again. If the temperature is still rising, it will change
the state of the cooling device to 2.
Now suppose that next time the zone temperature is updated, it falls
below the trip point, so tz->passive is decremented for the zone (say
it becomes 0 then) and the governor's .manage() callbacks runs.
It finds that the temperature trend for the zone is 'falling' and
'throttle' will be set to 'false' for the trip in question, so the
cooling device's state will be changed to 1. However, because
tz->polling is 0 for the zone, the governor's .manage() callback
may not be invoked again for a long time and the cooling device's
state will not be reset back to 0.
This can happen because commit 042a3d80f118 ("thermal: core: Move
passive polling management to the core") removed passive polling
management from the Step-Wise governor.
Before that change, thermal_zone_trip_update() would bump up
tz->passive when changing the target state for a thermal instance
from "no target" to a specific value and it would drop tz->passive
when changing it back to "no target" which would cause passive
polling to be active for the zone until the governor has reset the
states of all cooling devices. In particular, in the example above
tz->passive would be incremented when changing the state of the
cooling device from 0 to 1 and then it would be still nonzero when
the state of the cooling device was changed from 2 to 1.
To prevent this problem from occurring, restore the passive polling
management in the Step-Wise governor by partially reverting the
commit in question and update the comment in the restored code
to explain its role more clearly.
Fixes: 042a3d80f118 ("thermal: core: Move passive polling management to the core")
Closes: https://lore.kernel.org/linux-pm/ZmVfcEOxmjUHZTSX@hovoldconsulting.com
Reported-by: Johan Hovold <johan+linaro@kernel.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Passive polling is enabled by setting the 'passive' field in
struct thermal_zone_device to a positive value so long as the
'passive_delay_jiffies' field is greater than zero. It causes
the thermal core to actively check the thermal zone temperature
periodically which in theory should be done after crossing a
passive trip point on the way up in order to allow governors to
react more rapidly to temperature changes and adjust mitigation
more precisely.
However, the 'passive' field in struct thermal_zone_device is currently
managed by governors which is quite problematic. First of all, only
two governors, Step-Wise and Power Allocator, update that field at
all, so the other governors do not benefit from passive polling,
although in principle they should. Moreover, if the zone governor is
changed from, say, Step-Wise to Fair-Share after 'passive' has been
incremented by the former, it is not going to be reset back to zero by
the latter even if the zone temperature falls down below all passive
trip points.
For this reason, make handle_thermal_trip() increment 'passive'
to enable passive polling for the given thermal zone whenever a
passive trip point is crossed on the way up and decrement it
whenever a passive trip point is crossed on the way down. Also
remove the 'passive' field updates from governors and additionally
clear it in thermal_zone_device_init() to prevent passive polling
from being enabled after a system resume just beacuse it was enabled
before suspending the system.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
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Do some assorted cleanups in thermal_zone_trip_update():
* Compute the trend value upfront.
* Move old_target definition to the block where it is used.
* Adjust white space around diagnostic messages and locking.
* Use suitable field formatting in a message to avoid an explicit
cast to int.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
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In principle, the Step-Wise governor should take trip hysteresis into
account. After all, once a trip has been crossed on the way up,
mitigation is still needed until it is crossed on the way down.
For this reason, make it use trip thresholds that are computed by
the core when trips are crossed, so as to apply mitigations in the
hysteresis rages of trips that were crossed on the way up, but have
not been crossed on the way down yet.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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Make the Step-Wise governor use the new .manage() callback instead of
.throttle().
Even though using .throttle() is not particularly problematic for the
Step-Wise governor, using .manage() instead still allows it to reduce
overhead by updating all of the cooling devices once after setting
target values for all of the thermal instances.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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Make it more clear from the code flow that the passive polling status
updates only take place for passive trip points.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
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The step-wise governor's get_target_state() function contains redundant
braces, redundant parens and a redundant next_target local variable, so
get rid of all that stuff.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
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Modify the governor .throttle() callback definition so that it takes a
trip pointer instead of a trip index as its second argument, adjust the
governors accordingly and update the core code invoking .throttle().
This causes the governors to become independent of the representation
of the list of trips in the thermal zone structure.
This change is not expected to alter the general functionality.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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Fold update_passive_instance() into thermal_zone_trip_update() that is
its only caller so as to make the code in question easier to follow.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
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Replace the integer trip number stored in struct thermal_instance with
a pointer to the relevant trip and adjust the code using the structure
in question accordingly.
The main reason for making this change is to allow the trip point to
cooling device binding code more straightforward, as illustrated by
subsequent modifications of the ACPI thermal driver, but it also helps
to clarify the overall design and allows the governor code overhead to
be reduced (through subsequent modifications).
The only case in which it adds complexity is trip_point_show() that
needs to walk the trips[] table to find the index of the given trip
point, but this is not a critical path and the interface that
trip_point_show() belongs to is problematic anyway (for instance, it
doesn't cover the case when the same cooling devices is associated
with multiple trip points).
This is a preliminary change and the affected code will be refined by
a series of subsequent modifications of thermal governors, the core and
the ACPI thermal driver.
The general functionality is not expected to be affected by this change.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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For the algorithm of choosing the next target state in step_wise
governor, the code does the right thing but is implemented in a
way different from what the comment describes. And this hurts the code
readability.
As the logic in the comment is simpler, adjust the code logic to align
with the comment.
No functional change.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
[ rjw: Subject edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Commit 4102c4042a33 ("thermal/core: Remove DROP_FULL and RAISE_FULL")
removes support for THERMAL_TREND_RAISE_FULL/DROP_FULL but leaves the
comment unchanged.
Delete the obsolte comment about THERMAL_TREND_RAISE_FULL/DROP_FULL.
Fixes: 4102c4042a33 ("thermal/core: Remove DROP_FULL and RAISE_FULL")
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The traces are exported but only local to the thermal core code. On
the other side, the traces take the thermal zone device structure as
argument, thus they have to rely on the exported thermal.h header
file. As we want to move the structure to the private thermal core
header, first we have to relocate those traces to the same place as
many drivers do.
Cc: Steven Rostedt <rostedt@goodmis.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20230307133735.90772-2-daniel.lezcano@linaro.org
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The governors are using the ops->get_trip_* functions, Replace these
calls with thermal_zone_get_trip().
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> # IPA
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20221003092602.1323944-5-daniel.lezcano@linaro.org
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All the governors throttling ops are taking/releasing the lock at the
beginning and the end of the function.
We can move the mutex to the throttling call site instead.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20220805153834.2510142-4-daniel.lezcano@linaro.org
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The thermal zone lock is taken in the different places in the
throttling path.
At the first glance it does not hurt to move them at the beginning and
the end of the 'throttle' function. That will allow a consolidation of
the lock in the next following changes.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20220805153834.2510142-3-daniel.lezcano@linaro.org
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The trends DROP_FULL and RAISE_FULL are not used and were never used
in the past AFAICT. Remove these conditions as they seems to not be
handled anywhere.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20220629151012.3115773-2-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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The code is actually clampling the next cooling device state using the
lowest and highest states of the thermal instance.
That code can be replaced by the clamp() macro which does exactly the
same. It results in a simpler routine to read.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20220629151012.3115773-1-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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The code was reorganized in 2012 with the commit 0c01ebbfd3caf1.
The main change is a loop on the trip points array and a unconditional
call to the throttle() ops of the governors for each of them even if
the trip temperature is not reached yet.
With this change, the 'forced_passive' is no longer checked in the
thermal_zone_device_update() function but in the step wise governor's
throttle() callback.
As the force_passive does no belong to the trip point array, the
thermal_zone_device_update() can not compare with the specified
passive temperature, thus does not detect the passive limit has been
crossed. Consequently, throttle() is never called and the
'forced_passive' branch is unreached.
In addition, the default processor cooling device is not automatically
bound to the thermal zone if there is not passive trip point, thus the
'forced_passive' can not operate.
If there is an active trip point, then the throttle function will be
called to mitigate at this temperature and the 'forced_passive' will
override the mitigation of the active trip point in this case but with
the default cooling device bound to the thermal zone, so usually a
fan, and that is not a passive cooling effect.
Given the regression exists since more than 8 years, nobody complained
and at the best of my knowledge there is no bug open in
https://bugzilla.kernel.org, it is reasonable to say it is unused.
Remove the 'forced_passive' related code.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Thara Gopinath <thara.gopinath@linaro.org>
Link: https://lore.kernel.org/r/20201214233811.485669-1-daniel.lezcano@linaro.org
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Bang-bang governor source file is prefixed with gov_. Do the same for
other governors for consistency so they're easy to find in the sources.
Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/b9a85d3204712f14e320504948c12712dc0b291b.1589199124.git.amit.kucheria@linaro.org
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