Linux Threads Implementation Guide

In Linux, threads are implemented using the clone() system call. This system call can create a new process or thread and share resources with the caller, including memory space and file descriptors. Threads are lightweight processes, so the implementation of threads in Linux is very similar to processes, with the main difference being that when creating a thread, certain parameters are used to specify whether to share resources with the caller.

Specifically, the implementation of Linux threads is carried out through the following steps:

1. Thread creation: using the clone() system call to create a new thread, specifying shared resources with the caller. Common parameters include CLONE_VM (shared memory space), CLONE_FS (shared file system), CLONE_FILES (shared file descriptors), and so on.
2. Thread scheduling: The Linux kernel schedules the execution of threads based on their priority and the scheduling policy. The scheduler is responsible for thread scheduling, determining which thread should run based on specific policies.
3. Context switch of threads: When a thread is scheduled to run, the Linux kernel performs a context switch of threads, which involves saving the current thread’s state, loading the new thread’s state, and handing over control to the new thread.

Overall, the implementation of Linux threads is based on processes, utilizing resource sharing and scheduling to achieve concurrent execution of multiple threads. Threads are created using the clone() system call and their execution order is determined by the scheduler, enabling concurrent threading.