学步园

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/completion.h>

MODULE_LICENSE("Dual BSD/GPL");

#define PERIOD_THREAD_NUM 5

static int periods[PERIOD_THREAD_NUM] = 
	{ 1, 2, 4, 8, 16 };

static struct task_struct *period_tsks[PERIOD_THREAD_NUM];

static struct task_struct* watchdog_tsk;

static struct completion wakeups[PERIOD_THREAD_NUM];

static int exit_flag = 0;

static int period_thread(void *data)
{
	int k = (int)data;
	int count = -1;

	do{
		printk("thread%d: period=%ds, count=%d\n", k, periods[k], ++count);
		wait_for_completion(&wakeups[k]);
	}while(!exit_flag);
	return count;
}

static int watchdog_thread(void *data)
{
	int k;
	int count = 0;
	
	do{
		msleep(1000);
		count++;
		for(k=0; k<PERIOD_THREAD_NUM; k++){
			if (count%periods[k] == 0)
				complete(&wakeups[k]);
		}
	}while(!exit_flag);
	return count;
}

static int hello_init(void)
{
	int k;

	printk(KERN_INFO "Hello, world!\n");

	for(k=0; k<PERIOD_THREAD_NUM; k++){
		init_completion(&wakeups[k]);
	}

	watchdog_tsk = kthread_run(watchdog_thread, NULL, "watchdog_thread");

	if(IS_ERR(watchdog_tsk)){
		printk(KERN_INFO "create watchdog_thread failed!\n");
		return 1;
	}

	for(k=0; k<PERIOD_THREAD_NUM; k++){
		period_tsks[k] = kthread_run(period_thread, (void*)k, "period_thread%d", k);
		if(IS_ERR(period_tsks[k]))
			printk(KERN_INFO "create period_thread%d failed!\n", k);
	}
	return 0;
}

static void hello_exit(void)
{
	int k;
	int count[5], watchdog_count;

	printk(KERN_INFO "Hello, exit!\n");
	exit_flag = 1;
	for(k=0; k<PERIOD_THREAD_NUM]; k++)
		complete_all(&wakeups[k]);

	for(k=0; k<PERIOD_THREAD_NUM]; k++){
		count[k] = 0;
		if(!IS_ERR(period_tsks[k]))
			count[k] = kthread_stop(period_tsks[k]);
	}
	watchdog_count = 0;
	if(!IS_ERR(watchdog_tsk))
		watchdog_count = kthread_stop(watchdog_tsk);

	printk("running total time: %ds\n", watchdog_count);
	for(k=0; k<PERIOD_THREAD_NUM; k++)
		printk("thread%d: period %d, running %d times\n", k, periods[k], count[k]);
}

module_init(hello_init);
module_exit(hello_exit);