1 // SPDX-License-Identifier: GPL-2.0
8  * states for a specified fraction of time over a specified period.
13  * All of the kthreads used for idle injection are created at init time.
19  * The idle + run duration is specified via separate helpers and that allows
34  * It is up to the user of this framework to provide a lock for higher-level
50  * struct idle_inject_thread - task on/off switch structure
52  * @should_run: whether or not to run the task (for the smpboot kthread API)
60  * struct idle_inject_device - idle injection data
62  * @idle_duration_ms: duration of CPU idle time to inject
63  * @run_duration_ms: duration of CPU run time to allow
77  * idle_inject_wakeup - Wake up idle injection threads
88 	for_each_cpu_and(cpu, to_cpumask(ii_dev->cpumask), cpu_online_mask) {  in idle_inject_wakeup()
90 		iit->should_run = 1;  in idle_inject_wakeup()
91 		wake_up_process(iit->tsk);  in idle_inject_wakeup()
96  * idle_inject_timer_fn - idle injection timer function
101  * play_idle() to inject a specified amount of CPU idle time.
111 	duration_ms = READ_ONCE(ii_dev->run_duration_ms);  in idle_inject_timer_fn()
112 	duration_ms += READ_ONCE(ii_dev->idle_duration_ms);  in idle_inject_timer_fn()
122  * idle_inject_fn - idle injection work function
126  * time.
137 	 * Let the smpboot main loop know that the task should not run again.  in idle_inject_fn()
139 	iit->should_run = 0;  in idle_inject_fn()
141 	play_idle(READ_ONCE(ii_dev->idle_duration_ms));  in idle_inject_fn()
145  * idle_inject_set_duration - idle and run duration update helper
146  * @run_duration_ms: CPU run time to allow in milliseconds
147  * @idle_duration_ms: CPU idle time to inject in milliseconds
154 		WRITE_ONCE(ii_dev->run_duration_ms, run_duration_ms);  in idle_inject_set_duration()
155 		WRITE_ONCE(ii_dev->idle_duration_ms, idle_duration_ms);  in idle_inject_set_duration()
160  * idle_inject_get_duration - idle and run duration retrieval helper
161  * @run_duration_ms: memory location to store the current CPU run time
162  * @idle_duration_ms: memory location to store the current CPU idle time
168 	*run_duration_ms = READ_ONCE(ii_dev->run_duration_ms);  in idle_inject_get_duration()
169 	*idle_duration_ms = READ_ONCE(ii_dev->idle_duration_ms);  in idle_inject_get_duration()
173  * idle_inject_start - start idle injections
177  * injection kthreads associated with @ii_dev to let them inject CPU idle time
180  * Return: -EINVAL if the CPU idle or CPU run time is not set or 0 on success.
184 	unsigned int idle_duration_ms = READ_ONCE(ii_dev->idle_duration_ms);  in idle_inject_start()
185 	unsigned int run_duration_ms = READ_ONCE(ii_dev->run_duration_ms);  in idle_inject_start()
188 		return -EINVAL;  in idle_inject_start()
191 		 cpumask_pr_args(to_cpumask(ii_dev->cpumask)));  in idle_inject_start()
195 	hrtimer_start(&ii_dev->timer,  in idle_inject_start()
203  * idle_inject_stop - stops idle injections
207  * If CPU idle time is being injected when this function runs, then it will
219 		 cpumask_pr_args(to_cpumask(ii_dev->cpumask)));  in idle_inject_stop()
221 	hrtimer_cancel(&ii_dev->timer);  in idle_inject_stop()
238 	for_each_cpu(cpu, to_cpumask(ii_dev->cpumask)) {  in idle_inject_stop()
240 		iit->should_run = 0;  in idle_inject_stop()
242 		wait_task_inactive(iit->tsk, 0);  in idle_inject_stop()
249  * idle_inject_setup - prepare the current task for idle injection
263  * idle_inject_should_run - function helper for the smpboot API
266  * Return: whether or not the thread can run.
273 	return iit->should_run;  in idle_inject_should_run()
277  * idle_inject_register - initialize idle injection on a set of CPUs
296 	cpumask_copy(to_cpumask(ii_dev->cpumask), cpumask);  in idle_inject_register()
297 	hrtimer_init(&ii_dev->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);  in idle_inject_register()
298 	ii_dev->timer.function = idle_inject_timer_fn;  in idle_inject_register()
300 	for_each_cpu(cpu, to_cpumask(ii_dev->cpumask)) {  in idle_inject_register()
313 	for_each_cpu(cpu_rb, to_cpumask(ii_dev->cpumask)) {  in idle_inject_register()
325  * idle_inject_unregister - unregister idle injection control device
338 	for_each_cpu(cpu, to_cpumask(ii_dev->cpumask))  in idle_inject_unregister()