linux kernel 内核定时器

1.涉及函数

// 1. 初始化定时器队列结构
init_timer(&buttons_timer);

// 2. 定时器超时函数
buttons_timer.function = buttons_timer_function;

// 3.或者初始化定时器和超时函数作为一步（data作为fn的参数）
setup_timer(timer, fn, data)

// 4. 添加定时器
add_timer(&buttons_timer);

// 5. 设置定时器超时时间 1\100 s（修改一次超时时间只会触发一次定时器）
mod_timer(&buttons_timer, jiffies+HZ/100);

// 6.删除定时器
del_timer(&timer);

2.demo

#include linux/init.h>
#include linux/module.h>
#include linux/moduleparam.h>
#include linux/time.h>
#include linux/timer.h>
#include linux/workqueue.h>
#include asm/atomic.h>
MODULE_AUTHOR("lcw");
MODULE_LICENSE("GPL");

struct timer_data {
struct timer_list timer;
struct workqueue_struct *work_queue;
unsigned long prev_jiffies;
unsigned int loops;
};

static struct timer_list timer1;
static struct timer_list timer2;

static void do_work(void *);
static DECLARE_WORK(test_work, do_work, NULL);
static DECLARE_WORK(test_work1, do_work, NULL);
static struct workqueue_struct *test_workqueue;
atomic_t wq_run_times;
unsigned int failed_cnt = 0;

// 定时器1超时函数
void test_timer_fn1(unsigned long arg)
{
struct timer_data *data = (struct timer_data *)arg;

mod_timer(&timer1, jiffies+HZ/100); // 设置超时时间 1\100s

if (queue_work(test_workqueue, &test_work)== 0) {
printk("Timer (0) add work queue failed\n");
(*(&failed_cnt))++;
}
data->loops++;
printk("timer-0 loops: %u\n", data->loops);
}

// 定时器2超时函数
void test_timer_fn2(unsigned long arg)
{
struct timer_data *data = (struct timer_data *)arg;

mod_timer(&timer2, jiffies+HZ/100); // 设置超时时间 1\100s

//if (queue_work(test_workqueue, &test_work)== 0) {
if (queue_work(test_workqueue, &test_work1)== 0) {
printk("Timer (1) add work queue failed\n");
(*(&failed_cnt))++;
}
data->loops++;
printk("timer-1 loops: %u\n", data->loops);
}

// work func
void do_work(void*arg)
{
//原子计数值加一
atomic_inc(&wq_run_times);
printk("====work queue run times: %u====\n", atomic_read(&wq_run_times));
printk("====failed count: %u====\n",*(&failed_cnt));
}

// init
int wq_init(void)
{

//原子计数值初始化
atomic_set(&wq_run_times, 0);

// work queue
test_workqueue = create_singlethread_workqueue("test-wq");

// timer1
init_timer(&timer1);
timer1.function= test_timer_fn1;
add_timer(&timer1);

// timer2
init_timer(&timer2);
timer2.function= test_timer_fn1;
add_timer(&timer2);

//设置超时时间，启动定时器
mod_timer(&timer1, jiffies+HZ/100); // 设置超时时间 1\100s
mod_timer(&timer2, jiffies+HZ/100); // 设置超时时间 1\100s

return 0;
}

void wq_exit(void)
{
del_timer(&test_data.timer);
del_timer(&test_data1.timer);
destroy_workqueue(test_workqueue);
printk("wq exit success\n");
}

module_init(wq_init);
module_exit(wq_exit)