| Message ID | 20241022155147.463475-1-daniel.lezcano@linaro.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | Add thermal user thresholds support | expand |
Please note, I did not fixed the locking issue assuming it will be fixed when the series is applied as stated in v5. As soon as the series is merged, I will send a couple of changes, one to fix the memory leak and the other one to fix the warning reported by syszbot Thanks -- D. On 22/10/2024 17:51, Daniel Lezcano wrote: > The trip points are a firmware description of the temperature limits > of a specific thermal zone where we associate an action which is done > by the kernel. The time resolution is low. > > The userspace has to deal with a more complex thermal management based > on heuristics from different information coming from different > places. The logic is much more complex but based on a bigger time > resolution, usually one second based. > > The purpose of the userspace is to monitor the temperatures from > different places and take actions. However, it can not be constantly > reading the temperature to detect when a temperature threshold has > been reached. This is especially bad for mobile or embedded system as > that will lead to an unacceptable number of wakeup to check the > temperature with nothing to do. > > On the other side, the sensors are now most of the time interrupt > driven. That means the thermal framework will use the temperature trip > points to program the sensor to trigger an interrupt when a > temperature limit is crossed. > > Unfortunately, the userspace can not benefit this feature and current > solutions found here and there, iow out-of-tree, are to add fake trip > points in the firmware and enable the writable trip points. > > This is bad for different reasons, the trip points are for in-kernel > actions, the semantic of their types is used by the thermal framework > and by adding trip points in the device tree is a way to overcome the > current limitation but tampering with how the thermal framework is > supposed to work. The writable trip points is a way to adjust a > temperature limit given a specific platform if the firmware is not > accurate enough and TBH it is more a debug feature from my POV. > > The user thresholds mechanism is a way to have the userspace to tell > thermal framework to send a notification when a temperature limit is > crossed. There is no id, no hysteresis, just the temperature and the > direction of the limit crossing. That means we can be notified when a > temperature threshold is crossed the way up only, or the way down only > or both ways. That allows to create hysteresis values if it is needed. > > Those thresholds are refered as user thresholds in order to do the > difference with the trip points which are similar. > > An user threshold can be added, deleted or flushed. The latter means > all user thresholds belonging to a thermal zone will be deleted. > > When one or several user thresholds are crossed, an event is sent to > the userspace. > > All aforementioned actions and events lead to a notification to the > userspace. > > Along with the kernel changes, the thermal library has been extended > to provide the different API to deal with the new user threshold > netlink events and commands. > > In addition, the thermal-engine skeleton uses these new API by > flushing and adding user thresholds as well as getting the > notification about these actions. > > Overall the series has been tested with the thermal-engine skeleton > and some selftests which are not part of this series. > > Changelog: > V6: > > - Added a comment in the parse_threshold_get() function to clarify > how the size is computed (Lukasz) > > - Changed comparison to check against non zero value in the > __thermal_zone_discover() function (Lukasz) > > V5: > - Added CAP_SYS_ADMIN needed capability when adding, deleting and > flushing a threshold (Rafael) > > - Remove the pid information to prevent leaking pid inside > containers. Also the information is not really needed (Rafael) > > - Renamed "THERMAL_GENL_ATTR_THRESHOLD_WAY" to > "THERMAL_GENL_ATTR_THRESHOLD_DIRECTION". Did not used '*_DIR' as > suggested initially because it can be ambiguous with 'directory' > (Rafael) > > - Renamed 'last_temp' to 'prev_temp' (Rafael) > > - Used CLASS constructor/destructor to get / put the thermal > zone's device refcount (Rafael) > > - Moved locking inside thermal_thresholds_for_each() (Rafael) > > - Reflected the changes above in the thermal library and the > thermal engine skeleton > > > V4: > - Fix missing stubs when THERMAL_NETLINK=n (kernel test robot) > > V3: > - the first patch of the v2 series has been merged > > - Modified the description to split the information between the > cover letter and the patch 1 description (Rafael) > > - Made the thresholds code as part of the core (Rafael) > > - Converted the thresholds into a list and directly declared in > the thermal zone device structure (Rafael) > > - Changed the name of the field in the thermal zone device > structure to user_thresholds (Rafael) > > - Added #include "thermal_thresholds.h" (Rafael) > > - Combined the conditions in the function > __thermal_threshold_is_crossed (Rafael) > > - Moved the function thermal_thresholds_flush() before > thermal_thresholds_exit() (Rafael) > > - Change thermal_thresholds_handle() to return void (Rafael) > > - Move the list field on top the of the structure threshold and > renamed it list_node (Rafael) > > - Changed THERMAL_THRESHOLD_* notifications to > THERMAL_TZ_THRESHOLD_* (Rafael) > > V2: > - Compute min and max in thermal_zone_device_update() but keep > the loop as it is (Rafael) > > - Include slab.h to fix compilation warnings on some architectures > with kmalloc and kfree (kernel test robot) > > Daniel Lezcano (5): > thermal: core: Connect the threshold with the core > thermal/netlink: Add the commands and the events for the thresholds > tools/lib/thermal: Make more generic the command encoding function > tools/lib/thermal: Add the threshold netlink ABI > tools/thermal/thermal-engine: Take into account the thresholds API > > drivers/thermal/thermal_core.c | 9 + > drivers/thermal/thermal_netlink.c | 236 +++++++++++++++++- > drivers/thermal/thermal_netlink.h | 34 +++ > drivers/thermal/thermal_thresholds.c | 36 +-- > drivers/thermal/thermal_thresholds.h | 2 +- > include/uapi/linux/thermal.h | 27 +- > tools/lib/thermal/commands.c | 177 ++++++++++++- > tools/lib/thermal/events.c | 55 +++- > tools/lib/thermal/include/thermal.h | 40 +++ > tools/lib/thermal/libthermal.map | 5 + > tools/lib/thermal/thermal.c | 17 ++ > tools/thermal/lib/Makefile | 2 +- > tools/thermal/thermal-engine/thermal-engine.c | 105 +++++++- > 13 files changed, 681 insertions(+), 64 deletions(-) >
On Tue, Oct 22, 2024 at 5:54 PM Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > > > Please note, I did not fixed the locking issue assuming it will be fixed > when the series is applied as stated in v5. Yes. Applied now. Note that I have skipped patch [1/5] because it has been applied already before. It is on my bleeding-edge branch ATM since the commit IDs may still change. > As soon as the series is merged, I will send a couple of changes, one to > fix the memory leak and the other one to fix the warning reported by syszbot It should get to linux-next and thermal in a couple of days. Thanks!
Great thanks ! On 23/10/2024 12:31, Rafael J. Wysocki wrote: > On Tue, Oct 22, 2024 at 5:54 PM Daniel Lezcano > <daniel.lezcano@linaro.org> wrote: >> >> >> Please note, I did not fixed the locking issue assuming it will be fixed >> when the series is applied as stated in v5. > > Yes. > > Applied now. Note that I have skipped patch [1/5] because it has been > applied already before. > > It is on my bleeding-edge branch ATM since the commit IDs may still change. > >> As soon as the series is merged, I will send a couple of changes, one to >> fix the memory leak and the other one to fix the warning reported by syszbot > > It should get to linux-next and thermal in a couple of days. > > Thanks!
The trip points are a firmware description of the temperature limits of a specific thermal zone where we associate an action which is done by the kernel. The time resolution is low. The userspace has to deal with a more complex thermal management based on heuristics from different information coming from different places. The logic is much more complex but based on a bigger time resolution, usually one second based. The purpose of the userspace is to monitor the temperatures from different places and take actions. However, it can not be constantly reading the temperature to detect when a temperature threshold has been reached. This is especially bad for mobile or embedded system as that will lead to an unacceptable number of wakeup to check the temperature with nothing to do. On the other side, the sensors are now most of the time interrupt driven. That means the thermal framework will use the temperature trip points to program the sensor to trigger an interrupt when a temperature limit is crossed. Unfortunately, the userspace can not benefit this feature and current solutions found here and there, iow out-of-tree, are to add fake trip points in the firmware and enable the writable trip points. This is bad for different reasons, the trip points are for in-kernel actions, the semantic of their types is used by the thermal framework and by adding trip points in the device tree is a way to overcome the current limitation but tampering with how the thermal framework is supposed to work. The writable trip points is a way to adjust a temperature limit given a specific platform if the firmware is not accurate enough and TBH it is more a debug feature from my POV. The user thresholds mechanism is a way to have the userspace to tell thermal framework to send a notification when a temperature limit is crossed. There is no id, no hysteresis, just the temperature and the direction of the limit crossing. That means we can be notified when a temperature threshold is crossed the way up only, or the way down only or both ways. That allows to create hysteresis values if it is needed. Those thresholds are refered as user thresholds in order to do the difference with the trip points which are similar. An user threshold can be added, deleted or flushed. The latter means all user thresholds belonging to a thermal zone will be deleted. When one or several user thresholds are crossed, an event is sent to the userspace. All aforementioned actions and events lead to a notification to the userspace. Along with the kernel changes, the thermal library has been extended to provide the different API to deal with the new user threshold netlink events and commands. In addition, the thermal-engine skeleton uses these new API by flushing and adding user thresholds as well as getting the notification about these actions. Overall the series has been tested with the thermal-engine skeleton and some selftests which are not part of this series. Changelog: V6: - Added a comment in the parse_threshold_get() function to clarify how the size is computed (Lukasz) - Changed comparison to check against non zero value in the __thermal_zone_discover() function (Lukasz) V5: - Added CAP_SYS_ADMIN needed capability when adding, deleting and flushing a threshold (Rafael) - Remove the pid information to prevent leaking pid inside containers. Also the information is not really needed (Rafael) - Renamed "THERMAL_GENL_ATTR_THRESHOLD_WAY" to "THERMAL_GENL_ATTR_THRESHOLD_DIRECTION". Did not used '*_DIR' as suggested initially because it can be ambiguous with 'directory' (Rafael) - Renamed 'last_temp' to 'prev_temp' (Rafael) - Used CLASS constructor/destructor to get / put the thermal zone's device refcount (Rafael) - Moved locking inside thermal_thresholds_for_each() (Rafael) - Reflected the changes above in the thermal library and the thermal engine skeleton V4: - Fix missing stubs when THERMAL_NETLINK=n (kernel test robot) V3: - the first patch of the v2 series has been merged - Modified the description to split the information between the cover letter and the patch 1 description (Rafael) - Made the thresholds code as part of the core (Rafael) - Converted the thresholds into a list and directly declared in the thermal zone device structure (Rafael) - Changed the name of the field in the thermal zone device structure to user_thresholds (Rafael) - Added #include "thermal_thresholds.h" (Rafael) - Combined the conditions in the function __thermal_threshold_is_crossed (Rafael) - Moved the function thermal_thresholds_flush() before thermal_thresholds_exit() (Rafael) - Change thermal_thresholds_handle() to return void (Rafael) - Move the list field on top the of the structure threshold and renamed it list_node (Rafael) - Changed THERMAL_THRESHOLD_* notifications to THERMAL_TZ_THRESHOLD_* (Rafael) V2: - Compute min and max in thermal_zone_device_update() but keep the loop as it is (Rafael) - Include slab.h to fix compilation warnings on some architectures with kmalloc and kfree (kernel test robot) Daniel Lezcano (5): thermal: core: Connect the threshold with the core thermal/netlink: Add the commands and the events for the thresholds tools/lib/thermal: Make more generic the command encoding function tools/lib/thermal: Add the threshold netlink ABI tools/thermal/thermal-engine: Take into account the thresholds API drivers/thermal/thermal_core.c | 9 + drivers/thermal/thermal_netlink.c | 236 +++++++++++++++++- drivers/thermal/thermal_netlink.h | 34 +++ drivers/thermal/thermal_thresholds.c | 36 +-- drivers/thermal/thermal_thresholds.h | 2 +- include/uapi/linux/thermal.h | 27 +- tools/lib/thermal/commands.c | 177 ++++++++++++- tools/lib/thermal/events.c | 55 +++- tools/lib/thermal/include/thermal.h | 40 +++ tools/lib/thermal/libthermal.map | 5 + tools/lib/thermal/thermal.c | 17 ++ tools/thermal/lib/Makefile | 2 +- tools/thermal/thermal-engine/thermal-engine.c | 105 +++++++- 13 files changed, 681 insertions(+), 64 deletions(-)