内核线程:kernel_thread

简单的介绍一下内核线程函数：kernel_thread:

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/pid.h>

MODULE_LICENSE("GPL");

int my_thread(void *);

static int __init kthread_init(void)
{
    int result;

    printk("into kenrnel thread init...\n");
    result = kernel_thread(my_thread, NULL, CLONE_KERNEL);
    printk("kernel thread result is: %d\n", result);
    printk("<0>0 current pid is: %d, tgid is: %d\n", current->pid, current->tgid);

    return 0;
}

int my_thread(void *arg)
{
    printk("in the kernel thread function...\n");
    printk("<1>1 current pid is: %d, tgid is: %d\n", current->pid, current->tgid);

    return 0;
}

static void __exit kthread_exit(void)
{
    printk("kernel thread quit...\n");
}

module_init(kthread_init);
module_exit(kthread_exit);

MODULE_AUTHOR("ZHAOQIAO");

下面是Makefile文件：

obj-m := kthread.o

CURRENT_PATH = $(shell pwd)
KERNEL_PATH = $(shell uname -r)

kernel_path = /usr/src/linux-headers-$(KERNEL_PATH)/

all:
    make -C $(kernel_path) M=$(CURRENT_PATH) modules
clean:
    make -C $(kernel_path) M=$(CURRENT_PATH) clean

这样运行后的结果为：

[16546.959065] into kenrnel thread init...

[16546.959086] kernel thread result is: 12107

[16546.959088] 0 current pid is: 12105, tgid is: 12105

[16546.959502] in the kernel thread function...

[16546.959504] 1 current pid is: 12107, tgid is: 12107

[16549.485885] kernel thread quit...

这里的0和1两个线程为什么他们的tgid不一样呢？（PS：正在查。。。）