| Message ID | 20191113185419.13305-1-daniel.lezcano@linaro.org (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
| Series | [RFC,1/3] cpuidle: Replace use_deepest_state flag by use_latency | expand |
On Wed, Nov 13, 2019 at 7:54 PM Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > > We want to specify a latency constraint when choosing an idle state at > play_idle time. Instead of duplicating the information in the > structure or propagate the latency in the call stack, change the > use_deepest_state by use_latency to introduce this constraint. > > A zero latency constraint means "do not use the deepest idle state > path" as the 'use_deepest_state' boolean was used in the > cpuidle_idle_call. > > Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> > --- > drivers/cpuidle/cpuidle.c | 6 +++--- > include/linux/cpuidle.h | 6 +++--- > kernel/sched/idle.c | 6 +++--- > 3 files changed, 9 insertions(+), 9 deletions(-) > > diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c > index 44ae39f2b47a..f68a6c9e8482 100644 > --- a/drivers/cpuidle/cpuidle.c > +++ b/drivers/cpuidle/cpuidle.c > @@ -100,19 +100,19 @@ static int find_deepest_state(struct cpuidle_driver *drv, > > /** > * cpuidle_use_deepest_state - Set/clear governor override flag. > - * @enable: New value of the flag. > + * @latency: A latency constraint I would call this latency_limit. Maybe even latency_limit_ns (or us, whatever is more suitable), to make it clear which unit of time is used here. > * > * Set/unset the current CPU to use the deepest idle state (override governors > * going forward if set). I would update the comment too, something like: "Set/unset the current CPU to use the deepest idle state with the exit latency within @latency_limit" > */ > -void cpuidle_use_deepest_state(bool enable) > +void cpuidle_use_latency(unsigned int latency) I wouldn't change the name of the function (because why really?). > { > struct cpuidle_device *dev; > > preempt_disable(); > dev = cpuidle_get_device(); > if (dev) > - dev->use_deepest_state = enable; > + dev->use_latency = latency; > preempt_enable(); > } > > diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h > index d23a3b1ddcf6..32018704f4ea 100644 > --- a/include/linux/cpuidle.h > +++ b/include/linux/cpuidle.h > @@ -83,8 +83,8 @@ struct cpuidle_driver_kobj; > struct cpuidle_device { > unsigned int registered:1; > unsigned int enabled:1; > - unsigned int use_deepest_state:1; > unsigned int poll_time_limit:1; > + unsigned int use_latency; And maybe call this forced_idle_latency_limit or similar? The idea being that when it is set, idle is forced (i.e. no governors), but there is a latency limit for the state to use. > unsigned int cpu; > ktime_t next_hrtimer; > > @@ -210,7 +210,7 @@ extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv, > struct cpuidle_device *dev); > extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv, > struct cpuidle_device *dev); > -extern void cpuidle_use_deepest_state(bool enable); > +extern void cpuidle_use_latency(unsigned int latency); > #else > static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv, > struct cpuidle_device *dev) > @@ -218,7 +218,7 @@ static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv, > static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv, > struct cpuidle_device *dev) > {return -ENODEV; } > -static inline void cpuidle_use_deepest_state(bool enable) > +static inline void cpuidle_use_latency(unsigned int latency) > { > } > #endif > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c > index 8dad5aa600ea..00e064d3dfe1 100644 > --- a/kernel/sched/idle.c > +++ b/kernel/sched/idle.c > @@ -165,7 +165,7 @@ static void cpuidle_idle_call(void) > * until a proper wakeup interrupt happens. > */ > > - if (idle_should_enter_s2idle() || dev->use_deepest_state) { > + if (idle_should_enter_s2idle() || dev->use_latency) { > if (idle_should_enter_s2idle()) { > rcu_idle_enter(); > > @@ -328,7 +328,7 @@ void play_idle(unsigned long duration_us) > rcu_sleep_check(); > preempt_disable(); > current->flags |= PF_IDLE; > - cpuidle_use_deepest_state(true); > + cpuidle_use_latency(1); > > it.done = 0; > hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); > @@ -339,7 +339,7 @@ void play_idle(unsigned long duration_us) > while (!READ_ONCE(it.done)) > do_idle(); > > - cpuidle_use_deepest_state(false); > + cpuidle_use_latency(0); > current->flags &= ~PF_IDLE; > > preempt_fold_need_resched(); > --
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 44ae39f2b47a..f68a6c9e8482 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -100,19 +100,19 @@ static int find_deepest_state(struct cpuidle_driver *drv, /** * cpuidle_use_deepest_state - Set/clear governor override flag. - * @enable: New value of the flag. + * @latency: A latency constraint * * Set/unset the current CPU to use the deepest idle state (override governors * going forward if set). */ -void cpuidle_use_deepest_state(bool enable) +void cpuidle_use_latency(unsigned int latency) { struct cpuidle_device *dev; preempt_disable(); dev = cpuidle_get_device(); if (dev) - dev->use_deepest_state = enable; + dev->use_latency = latency; preempt_enable(); } diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index d23a3b1ddcf6..32018704f4ea 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -83,8 +83,8 @@ struct cpuidle_driver_kobj; struct cpuidle_device { unsigned int registered:1; unsigned int enabled:1; - unsigned int use_deepest_state:1; unsigned int poll_time_limit:1; + unsigned int use_latency; unsigned int cpu; ktime_t next_hrtimer; @@ -210,7 +210,7 @@ extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv, struct cpuidle_device *dev); extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv, struct cpuidle_device *dev); -extern void cpuidle_use_deepest_state(bool enable); +extern void cpuidle_use_latency(unsigned int latency); #else static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv, struct cpuidle_device *dev) @@ -218,7 +218,7 @@ static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv, static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv, struct cpuidle_device *dev) {return -ENODEV; } -static inline void cpuidle_use_deepest_state(bool enable) +static inline void cpuidle_use_latency(unsigned int latency) { } #endif diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 8dad5aa600ea..00e064d3dfe1 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -165,7 +165,7 @@ static void cpuidle_idle_call(void) * until a proper wakeup interrupt happens. */ - if (idle_should_enter_s2idle() || dev->use_deepest_state) { + if (idle_should_enter_s2idle() || dev->use_latency) { if (idle_should_enter_s2idle()) { rcu_idle_enter(); @@ -328,7 +328,7 @@ void play_idle(unsigned long duration_us) rcu_sleep_check(); preempt_disable(); current->flags |= PF_IDLE; - cpuidle_use_deepest_state(true); + cpuidle_use_latency(1); it.done = 0; hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); @@ -339,7 +339,7 @@ void play_idle(unsigned long duration_us) while (!READ_ONCE(it.done)) do_idle(); - cpuidle_use_deepest_state(false); + cpuidle_use_latency(0); current->flags &= ~PF_IDLE; preempt_fold_need_resched();
We want to specify a latency constraint when choosing an idle state at play_idle time. Instead of duplicating the information in the structure or propagate the latency in the call stack, change the use_deepest_state by use_latency to introduce this constraint. A zero latency constraint means "do not use the deepest idle state path" as the 'use_deepest_state' boolean was used in the cpuidle_idle_call. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> --- drivers/cpuidle/cpuidle.c | 6 +++--- include/linux/cpuidle.h | 6 +++--- kernel/sched/idle.c | 6 +++--- 3 files changed, 9 insertions(+), 9 deletions(-)