Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Fri, 8 Nov 2019 11:56:43 +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 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").
> 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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