init_timer，初始化add_timer，启动mod_timer，修改del_timer，删除
timer_list结构function定时函数data定时函数所需的参数expires期望的定时时间如jiffies+xx*HZ表示几秒后
// declare timer_list, define functionstruct timer_list* ti;static void timer_handler(unsigned long l){// do something// then start timer againmod_timer((timer_list*)l, jiffers+2*HZ);}
// start timerti = kmalloc(sizeof(struct timer_list)), GFP_KERNEL);init_timer(ti);ti->expires = jiffers+2*HZ;ti->data = (unsigned long)ti;ti->function = &timer_handler;add_timer(ti);
