Messages in this thread | | | Subject | Re: [PATCH V6 2/3] cpuidle: play_idle: Specify play_idle with an idle state | From | Daniel Lezcano <> | Date | Fri, 8 Nov 2019 14:32:59 +0100 |
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On 08/11/2019 11:56, Rafael J. Wysocki wrote: > On Fri, Nov 8, 2019 at 11:47 AM Daniel Lezcano > <daniel.lezcano@linaro.org> wrote: >> >> On 08/11/2019 02:20, Rafael J. Wysocki wrote: >>> On Wednesday, October 30, 2019 8:51:40 AM CET Daniel Lezcano wrote: >>>> Currently, the play_idle function does not allow to tell which idle >>>> state we want to go. Improve this by passing the idle state as >>>> parameter to the function. >>>> >>>> Export cpuidle_find_deepest_state() symbol as it is used from the >>>> intel_powerclamp driver as a module. >>>> >>>> There is no functional changes, the cpuidle state is the deepest one. >>>> >>>> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> >>>> Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org> >>>> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> >>>> --- >>>> V6: >>>> - Change variable name 'state' -> 'index': >>>> https://lkml.org/lkml/2019/10/28/874 >>>> V4: >>>> - Add EXPORT_SYMBOL_GPL(cpuidle_find_deepest_state) for the >>>> intel_powerclamp driver when this one is compiled as a module >>>> V3: >>>> - Add missing cpuidle.h header >>>> --- >>>> drivers/cpuidle/cpuidle.c | 1 + >>>> drivers/powercap/idle_inject.c | 4 +++- >>>> drivers/thermal/intel/intel_powerclamp.c | 4 +++- >>>> include/linux/cpu.h | 2 +- >>>> kernel/sched/idle.c | 4 ++-- >>>> 5 files changed, 10 insertions(+), 5 deletions(-) >>>> >>>> diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c >>>> index 18523ea6b11b..b871fc2e8e67 100644 >>>> --- a/drivers/cpuidle/cpuidle.c >>>> +++ b/drivers/cpuidle/cpuidle.c >>>> @@ -126,6 +126,7 @@ int cpuidle_find_deepest_state(void) >>>> >>>> return find_deepest_state(drv, dev, UINT_MAX, 0, false); >>>> } >>>> +EXPORT_SYMBOL_GPL(cpuidle_find_deepest_state); >>> >>> That doesn't appear to be really necessary to me. >>> >>>> >>>> #ifdef CONFIG_SUSPEND >>>> static void enter_s2idle_proper(struct cpuidle_driver *drv, >>>> diff --git a/drivers/powercap/idle_inject.c b/drivers/powercap/idle_inject.c >>>> index cd1270614cc6..233c878cbf46 100644 >>>> --- a/drivers/powercap/idle_inject.c >>>> +++ b/drivers/powercap/idle_inject.c >>>> @@ -38,6 +38,7 @@ >>>> #define pr_fmt(fmt) "ii_dev: " fmt >>>> >>>> #include <linux/cpu.h> >>>> +#include <linux/cpuidle.h> >>>> #include <linux/hrtimer.h> >>>> #include <linux/kthread.h> >>>> #include <linux/sched.h> >>>> @@ -138,7 +139,8 @@ static void idle_inject_fn(unsigned int cpu) >>>> */ >>>> iit->should_run = 0; >>>> >>>> - play_idle(READ_ONCE(ii_dev->idle_duration_us)); >>>> + play_idle(READ_ONCE(ii_dev->idle_duration_us), >>>> + cpuidle_find_deepest_state()); >>> >>> The next patch changes this again and I'm not sure why this intermediate >>> change is useful. >>> >>>> } >>>> >>>> /** >>>> diff --git a/drivers/thermal/intel/intel_powerclamp.c b/drivers/thermal/intel/intel_powerclamp.c >>>> index 53216dcbe173..b55786c169ae 100644 >>>> --- a/drivers/thermal/intel/intel_powerclamp.c >>>> +++ b/drivers/thermal/intel/intel_powerclamp.c >>>> @@ -29,6 +29,7 @@ >>>> #include <linux/delay.h> >>>> #include <linux/kthread.h> >>>> #include <linux/cpu.h> >>>> +#include <linux/cpuidle.h> >>>> #include <linux/thermal.h> >>>> #include <linux/slab.h> >>>> #include <linux/tick.h> >>>> @@ -430,7 +431,8 @@ static void clamp_idle_injection_func(struct kthread_work *work) >>>> if (should_skip) >>>> goto balance; >>>> >>>> - play_idle(jiffies_to_usecs(w_data->duration_jiffies)); >>>> + play_idle(jiffies_to_usecs(w_data->duration_jiffies), >>>> + cpuidle_find_deepest_state()); >>> >>> I don't see a reason for changing the code here like this. >>> >>> What you really need is to have a way to set a limit on the idle >>> state exit latency for idle injection on ARM. >> >> Mmh, yes you are right. The idle state number is part of the internals >> of the cpuidle framework while the exit latency is an input (from user >> or kernel). >> >>> For that you can pass the exit latency limit to play_idle(), but then >>> you need to change powerclamp to pass UNIT_MAX or similar which is >>> ugly, or you can redefine cpuidle_use_deepest_state() to take the >>> exit latency limit as the arg (with 0 meaning use_deepest_state == false). >> >> Should it make sense to just get the resume latency in >> cpuidle_use_deepest_state() and pass the value to find_deepest_state()? > > Yes, I would change cpuidle_use_deepest_state() to take the max exit > latency as the arg (maybe with 0 meaning "don't use the deepest state > only any more").
Why not simply ?
int cpuidle_find_deepest_state(struct cpuidle_driver *drv, struct cpuidle_device *dev) { int latency = cpuidle_governor_latency_req(dev->cpu);
return find_deepest_state(drv, dev, latency_req, 0, false); }
>> It is the only code path where the constraint is not taken into account >> AFAICT. >> >> With this simple change, we can manage everything from the pm_qos API >> then and this series is no longer needed. > > OK >
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