From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Thompson Subject: Re: [PATCH 5/8] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver Date: Mon, 5 Feb 2018 13:54:43 +0000 Message-ID: References: <1516721671-16360-1-git-send-email-daniel.lezcano@linaro.org> <1516721671-16360-6-git-send-email-daniel.lezcano@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wr0-f193.google.com ([209.85.128.193]:37762 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753037AbeBENys (ORCPT ); Mon, 5 Feb 2018 08:54:48 -0500 Received: by mail-wr0-f193.google.com with SMTP id a43so22101371wrc.4 for ; Mon, 05 Feb 2018 05:54:47 -0800 (PST) In-Reply-To: <1516721671-16360-6-git-send-email-daniel.lezcano@linaro.org> Content-Language: en-US Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Daniel Lezcano , edubezval@gmail.com Cc: kevin.wangtao@linaro.org, leo.yan@linaro.org, vincent.guittot@linaro.org, amit.kachhap@gmail.com, viresh.kumar@linaro.org, linux-kernel@vger.kernel.org, Zhang Rui , Javi Merino , "open list:THERMAL" On 23/01/18 15:34, Daniel Lezcano wrote: > +/** > + * cpuidle_cooling_get_max_state - Get the maximum state > + * @cdev : the thermal cooling device > + * @state : a pointer to the state variable to be filled > + * > + * The function gives always 100 as the injection ratio is percentile > + * based for consistency accros different platforms. > + * > + * The function can not fail, it returns always zero. > + */ > +static int cpuidle_cooling_get_max_state(struct thermal_cooling_device *cdev, > + unsigned long *state) > +{ > + /* > + * Depending on the configuration or the hardware, the running > + * cycle and the idle cycle could be different. We want unify > + * that to an 0..100 interval, so the set state interface will > + * be the same whatever the platform is. > + * > + * The state 100% will make the cluster 100% ... idle. A 0% > + * injection ratio means no idle injection at all and 50% > + * means for 10ms of idle injection, we have 10ms of running > + * time. > + */ > + *state = 100; Doesn't this requires DTs to be changed? Basically the existing bindings for cpu cooling dictate that cooling-max-levels == num OPPs - 1 . Likewise I think cooling-max-levels *defines* the scale used by the cooling maps in the DT. Introducing an alternative scale means that the OPP limits in the cooling-map will be misinterpreted when we bind the cooling device. Note that we get away with this on Hikey because its mainline cooling map is, AFAICT, deeply sub-optimal and doesn't set any cooling limits. If its cooling map has been tuned (as the Exynos ones are) then I suspect there could be overheating problems when the cpuidle (or combo) CPU coolers are enabled. Daniel. > + > + return 0; > +} > + > +/** > + * cpuidle_cooling_get_cur_state - Get the current cooling state > + * @cdev: the thermal cooling device > + * @state: a pointer to the state > + * > + * The function just copy the state value from the private thermal > + * cooling device structure, the mapping is 1 <-> 1. > + * > + * The function can not fail, it returns always zero. > + */ > +static int cpuidle_cooling_get_cur_state(struct thermal_cooling_device *cdev, > + unsigned long *state) > +{ > + struct cpuidle_cooling_device *idle_cdev = cdev->devdata; > + > + *state = idle_cdev->state; > + > + return 0; > +} > + > +/** > + * cpuidle_cooling_set_cur_state - Set the current cooling state > + * @cdev: the thermal cooling device > + * @state: the target state > + * > + * The function checks first if we are initiating the mitigation which > + * in turn wakes up all the idle injection tasks belonging to the idle > + * cooling device. In any case, it updates the internal state for the > + * cooling device. > + * > + * The function can not fail, it returns always zero. > + */ > +static int cpuidle_cooling_set_cur_state(struct thermal_cooling_device *cdev, > + unsigned long state) > +{ > + struct cpuidle_cooling_device *idle_cdev = cdev->devdata; > + unsigned long current_state = idle_cdev->state; > + > + idle_cdev->state = state; > + > + if (current_state == 0 && state > 0) { > + pr_debug("Starting cooling cpus '%*pbl'\n", > + cpumask_pr_args(idle_cdev->cpumask)); > + cpuidle_cooling_wakeup(idle_cdev); > + } else if (current_state > 0 && !state) { > + pr_debug("Stopping cooling cpus '%*pbl'\n", > + cpumask_pr_args(idle_cdev->cpumask)); > + } > + > + return 0; > +} > + > +/** > + * cpuidle_cooling_ops - thermal cooling device ops > + */ > +static struct thermal_cooling_device_ops cpuidle_cooling_ops = { > + .get_max_state = cpuidle_cooling_get_max_state, > + .get_cur_state = cpuidle_cooling_get_cur_state, > + .set_cur_state = cpuidle_cooling_set_cur_state, > +}; > + > +/** > + * cpuidle_cooling_release - Kref based release helper > + * @kref: a pointer to the kref structure > + * > + * This function is automatically called by the kref_put function when > + * the idle cooling device refcount reaches zero. At this point, we > + * have the guarantee the structure is no longer in use and we can > + * safely release all the ressources. > + */ > +static void __init cpuidle_cooling_release(struct kref *kref) > +{ > + struct cpuidle_cooling_device *idle_cdev = > + container_of(kref, struct cpuidle_cooling_device, kref); > + > + thermal_cooling_device_unregister(idle_cdev->cdev); > + kfree(idle_cdev->waitq); > + kfree(idle_cdev->tsk); > + kfree(idle_cdev); > +} > + > +/** > + * cpuidle_cooling_register - Idle cooling device initialization function > + * > + * This function is in charge of creating a cooling device per cluster > + * and register it to thermal framework. For this we rely on the > + * topology as there is nothing yet describing better the idle state > + * power domains. > + * > + * For each first CPU of the cluster's cpumask, we allocate the idle > + * cooling device, initialize the general fields and then we initialze > + * the rest in a per cpu basis. > + * > + * Returns zero on success, < 0 otherwise. > + */ > +int cpuidle_cooling_register(void) > +{ > + struct cpuidle_cooling_device *idle_cdev = NULL; > + struct thermal_cooling_device *cdev; > + struct task_struct *tsk; > + struct device_node *np; > + cpumask_t *cpumask; > + char dev_name[THERMAL_NAME_LENGTH]; > + int weight; > + int ret = -ENOMEM, cpu; > + int index = 0; > + > + for_each_possible_cpu(cpu) { > + > + cpumask = topology_core_cpumask(cpu); > + weight = cpumask_weight(cpumask); > + > + /* > + * This condition makes the first cpu belonging to the > + * cluster to create a cooling device and allocates > + * the structure. Others CPUs belonging to the same > + * cluster will just increment the refcount on the > + * cooling device structure and initialize it. > + */ > + if (cpu == cpumask_first(cpumask)) { > + > + np = of_cpu_device_node_get(cpu); > + > + idle_cdev = kzalloc(sizeof(*idle_cdev), GFP_KERNEL); > + if (!idle_cdev) > + goto out_fail; > + > + idle_cdev->tsk = kzalloc(sizeof(*idle_cdev->tsk) * > + weight, GFP_KERNEL); > + if (!idle_cdev->tsk) > + goto out_fail; > + > + idle_cdev->waitq = kzalloc(sizeof(*idle_cdev->waitq) * > + weight, GFP_KERNEL); > + if (!idle_cdev->waitq) > + goto out_fail; > + > + idle_cdev->idle_cycle = DEFAULT_IDLE_TIME_US; > + > + atomic_set(&idle_cdev->count, 0); > + > + kref_init(&idle_cdev->kref); > + > + /* > + * Initialize the timer to wakeup all the idle > + * injection tasks > + */ > + hrtimer_init(&idle_cdev->timer, > + CLOCK_MONOTONIC, HRTIMER_MODE_REL); > + > + /* > + * The wakeup function callback which is in > + * charge of waking up all CPUs belonging to > + * the same cluster > + */ > + idle_cdev->timer.function = cpuidle_cooling_wakeup_fn; > + > + /* > + * The thermal cooling device name > + */ > + snprintf(dev_name, sizeof(dev_name), "thermal-idle-%d", index++); > + cdev = thermal_of_cooling_device_register(np, dev_name, > + idle_cdev, > + &cpuidle_cooling_ops); > + if (IS_ERR(cdev)) { > + ret = PTR_ERR(cdev); > + goto out_fail; > + } > + > + idle_cdev->cdev = cdev; > + > + idle_cdev->cpumask = cpumask; > + > + list_add(&idle_cdev->node, &cpuidle_cdev_list); > + > + pr_info("Created idle cooling device for cpus '%*pbl'\n", > + cpumask_pr_args(cpumask)); > + } > + > + kref_get(&idle_cdev->kref); > + > + /* > + * Each cooling device is per package. Each package > + * has a set of cpus where the physical number is > + * duplicate in the kernel namespace. We need a way to > + * address the waitq[] and tsk[] arrays with index > + * which are not Linux cpu numbered. > + * > + * One solution is to use the > + * topology_core_id(cpu). Other solution is to use the > + * modulo. > + * > + * eg. 2 x cluster - 4 cores. > + * > + * Physical numbering -> Linux numbering -> % nr_cpus > + * > + * Pkg0 - Cpu0 -> 0 -> 0 > + * Pkg0 - Cpu1 -> 1 -> 1 > + * Pkg0 - Cpu2 -> 2 -> 2 > + * Pkg0 - Cpu3 -> 3 -> 3 > + * > + * Pkg1 - Cpu0 -> 4 -> 0 > + * Pkg1 - Cpu1 -> 5 -> 1 > + * Pkg1 - Cpu2 -> 6 -> 2 > + * Pkg1 - Cpu3 -> 7 -> 3 > + */ > + init_waitqueue_head(&idle_cdev->waitq[cpu % weight]); > + > + tsk = kthread_create_on_cpu(cpuidle_cooling_injection_thread, > + idle_cdev, cpu, "kidle_inject/%u"); > + if (IS_ERR(tsk)) { > + ret = PTR_ERR(tsk); > + goto out_fail; > + } > + > + idle_cdev->tsk[cpu % weight] = tsk; > + > + wake_up_process(tsk); > + } > + > + return 0; > + > +out_fail: > + list_for_each_entry(idle_cdev, &cpuidle_cdev_list, node) { > + > + for_each_cpu(cpu, idle_cdev->cpumask) { > + > + if (idle_cdev->tsk[cpu]) > + kthread_stop(idle_cdev->tsk[cpu]); > + > + kref_put(&idle_cdev->kref, cpuidle_cooling_release); > + } > + } > + > + pr_err("Failed to create idle cooling device (%d)\n", ret); > + > + return ret; > +} > +#endif > diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h > index d4292eb..2b5950b 100644 > --- a/include/linux/cpu_cooling.h > +++ b/include/linux/cpu_cooling.h > @@ -45,6 +45,7 @@ struct thermal_cooling_device * > cpufreq_power_cooling_register(struct cpufreq_policy *policy, > u32 capacitance, get_static_t plat_static_func); > > +extern int cpuidle_cooling_register(void); > /** > * of_cpufreq_cooling_register - create cpufreq cooling device based on DT. > * @np: a valid struct device_node to the cooling device device tree node. > @@ -118,6 +119,11 @@ void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev) > { > return; > } > + > +static inline int cpuidle_cooling_register(void) > +{ > + return 0; > +} > #endif /* CONFIG_CPU_THERMAL */ > > #endif /* __CPU_COOLING_H__ */ >