All the different calls inside the thermal_zone_device_update()
function take the mutex.
The previous changes move the mutex out of the different functions,
like the throttling ops. Now that the mutexes are all at the same
level in the call stack for the thermal_zone_device_update() function,
they can be moved inside this one.
That has the benefit of:
1. Simplify the code by not having a plethora of places where the lock is taken
2. Probably closes more race windows because releasing the lock from
one line to another can give the opportunity to the thermal zone to change
its state in the meantime. For example, the thermal zone can be
enabled right after checking it is disabled.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20220805153834.2510142-5-daniel.lezcano@linaro.org
This extends the sysfs interface for thermal cooling devices and exposes
some pretty useful statistics. These statistics have proven to be quite
useful specially while doing benchmarks related to the task scheduler,
where we want to make sure that nothing has disrupted the test,
specially the cooling device which may have put constraints on the CPUs.
The information exposed here tells us to what extent the CPUs were
constrained by the thermal framework.
The write-only "reset" file is used to reset the statistics.
The read-only "time_in_state_ms" file shows the time (in msec) spent by the
device in the respective cooling states, and it prints one line per
cooling state.
The read-only "total_trans" file shows single positive integer value
showing the total number of cooling state transitions the device has
gone through since the time the cooling device is registered or the time
when statistics were reset last.
The read-only "trans_table" file shows a two dimensional matrix, where
an entry <i,j> (row i, column j) represents the number of transitions
from State_i to State_j.
This is how the directory structure looks like for a single cooling
device:
$ ls -R /sys/class/thermal/cooling_device0/
/sys/class/thermal/cooling_device0/:
cur_state max_state power stats subsystem type uevent
/sys/class/thermal/cooling_device0/power:
autosuspend_delay_ms runtime_active_time runtime_suspended_time
control runtime_status
/sys/class/thermal/cooling_device0/stats:
reset time_in_state_ms total_trans trans_table
This is tested on ARM 64-bit Hisilicon hikey620 board running Ubuntu and
ARM 64-bit Hisilicon hikey960 board running Android.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
