Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Sun, 10 Nov 2019 17:49:10 +0100 | Subject | Re: [PATCH V6 2/3] cpuidle: play_idle: Specify play_idle with an idle state |
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On Fri, Nov 8, 2019 at 2:33 PM Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > > 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); > }
Because, AFAICS, that doesn't work for powerclamp.
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