linux timer using example

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本文介绍了一个简单的Linux定时器模块实现案例，该模块通过初始化定时器并设置回调函数，在指定时间间隔触发自定义任务。文章展示了如何使用Linux内核API进行定时任务调度，并提供了完整的Makefile配置用于模块编译。

code:

#include <linux/init.h>
#include <linux/module.h>
#include <linux/hardirq.h>

MODULE_LICENSE("Dual BSD/GPL");



static struct timer_list timer_data;
static int counter = 0;
static void test_timer(unsigned long temp)
{
	int ret = 0;

	printk("test_timer()++\n");
	
	ret = in_interrupt();
	printk("in_interrupt ret = %d\n",ret);
	ret = in_atomic();
	printk("in_atomic ret = %d\n",ret);
	printk("counter = %d\n", counter++);
	mod_timer(&timer_data, jiffies + HZ);

	printk("test_timer()--\n");	
}
char *ptest_str = "Hello test_timer\n";
static int mmap_init(void)
{
	printk(KERN_ALERT"mmap_init()++\n");
	
	init_timer(&timer_data);
	timer_data.expires = jiffies + HZ;
	timer_data.data = (unsigned long) ptest_str;
	timer_data.function = test_timer;
	add_timer(&timer_data);
	
	printk(KERN_ALERT"mmap_init()--\n");
	
	return 0;
}

static void mmap_exit(void)
{
	printk(KERN_ALERT"mmap_exit()++\n");

	del_timer(&timer_data);
	
	printk(KERN_ALERT"mmap_exit()--\n");	
}

module_init(mmap_init);
module_exit(mmap_exit);

Makefile:

#obj-$(CONFIG_MMP_TEST)         += mmap.o

obj-m := helloworld.o
KERNELDR := /usr/src/linux-headers-2.6.32-38-generic/
PWD := $(shell pwd)
modules:
   $(MAKE) -C $(KERNELDR) M=$(PWD) modules
   echo "make modules"
moduels_install:
$(MAKE) -C $(KERNELDR) M=$(PWD) modules_install
clean:
   rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions

test enviroment: X86