Messages in this thread |  | | From | Vincent Guittot <> | Date | Fri, 23 Feb 2018 16:26:55 +0100 | Subject | Re: [PATCH V2 6/7] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver |
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Hi Daniel,
On 21 February 2018 at 16:29, Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > + > +/** > + * struct cpuidle_cooling_device - data for the idle cooling device > + * @cdev: a pointer to a struct thermal_cooling_device > + * @cpumask: a cpumask containing the CPU managed by the cooling device > + * @timer: a hrtimer giving the tempo for the idle injection cycles > + * @kref: a kernel refcount on this structure > + * @count: an atomic to keep track of the last task exiting the idle cycle > + * @idle_cycle: an integer defining the duration of the idle injection > + * @state: an normalized integer giving the state of the cooling device > + */ > +struct cpuidle_cooling_device { > + struct thermal_cooling_device *cdev; > + struct cpumask *cpumask; > + struct list_head node; > + struct hrtimer timer; > + struct kref kref; > + atomic_t count; > + unsigned int idle_cycle; > + unsigned int state; > +}; > + > +/** > + * @tsk: an array of pointer to the idle injection tasks > + * @waitq: the waiq for the idle injection tasks > + */ > +struct cpuidle_cooling_tsk { > + struct task_struct *tsk; > + wait_queue_head_t waitq;
Why are you creating one wait_queue_head_t per cpu instead of one per cooling device and then save a pointer in the per cpu struct cpuidle_cooling_tsk ? Then, you can use wake_up_interruptible_all() to wake up all threads instead of using for_each_cpu ... wake_up_process() loop in cpuidle_cooling_wakeup() ?
> +}; > + > +DEFINE_PER_CPU(struct cpuidle_cooling_tsk, cpuidle_cooling_tsk); > + > +static LIST_HEAD(cpuidle_cdev_list); > + > +/** > + * cpuidle_cooling_wakeup - Wake up all idle injection threads > + * @idle_cdev: the idle cooling device > + * > + * Every idle injection task belonging to the idle cooling device and > + * running on an online cpu will be wake up by this call. > + */ > +static void cpuidle_cooling_wakeup(struct cpuidle_cooling_device *idle_cdev) > +{ > + int cpu; > + struct cpuidle_cooling_tsk *cct; > + > + for_each_cpu_and(cpu, idle_cdev->cpumask, cpu_online_mask) { > + cct = per_cpu_ptr(&cpuidle_cooling_tsk, cpu); > + wake_up_process(cct->tsk); > + } > +} > + > +/** > + * cpuidle_cooling_wakeup_fn - Running cycle timer callback > + * @timer: a hrtimer structure > + * > + * When the mitigation is acting, the CPU is allowed to run an amount > + * of time, then the idle injection happens for the specified delay > + * and the idle task injection schedules itself until the timer event > + * wakes the idle injection tasks again for a new idle injection > + * cycle. The time between the end of the idle injection and the timer > + * expiration is the allocated running time for the CPU. > + * > + * Returns always HRTIMER_NORESTART > + */ > +static enum hrtimer_restart cpuidle_cooling_wakeup_fn(struct hrtimer *timer) > +{ > + struct cpuidle_cooling_device *idle_cdev = > + container_of(timer, struct cpuidle_cooling_device, timer); > + > + cpuidle_cooling_wakeup(idle_cdev); > + > + return HRTIMER_NORESTART; > +} > + > +/**
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