Shulou(Shulou.com)06/01 Report--

This article mainly explains "what is the implementation principle of Linux mutex". Interested friends may wish to take a look at it. The method introduced in this paper is simple, fast and practical. Next, let the editor take you to learn "what is the implementation principle of Linux mutex lock"?

Mutex (Mutex) is a semaphore behavior based on atomic operation API. Mutex cannot be locked or unlocked recursively, can be used in interactive context but cannot be used in interrupt context, only one task can hold mutex at a time, and only this task can unlock mutex.

Introduction mutexes are most commonly used, but it takes a lot of work to understand how they work. Although we say that mutexes are used to protect a critical area, they actually protect the manipulated data in the critical area.

Mutexes are still divided into three categories: fast mutex / recursive mutex / detection mutex

For futex to understand the internal implementation of mutexes, first take a look at the role of futex (fast Userspace mutexes).

The hybrid mechanism of kernel state and user mode.

How does the kernel maintain synchronization and mutual exclusion without futex? The system kernel maintains an object that is visible to all processes, which is used to manage mutexes and notify blocked processes. If process A wants to enter the critical section, first go to the kernel to check the object, whether there are other processes occupying the critical area, when leaving the critical area, also go to the kernel to check this object, whether there are other processes waiting to enter the critical area.

Mutex 1. The structure of mutex?

In the futex based on the use of memory sharing variables to achieve.

2. How do you enter dormancy when you cannot lock it, and how do you wait to be awakened?

The shared variable is checked when the lock is entered, and if the lock cannot be acquired, it will go to sleep through the futex system call. If someone releases the lock, it will be awakened by futex.

3. The properties of mutexes?

Specifies the scope of the lock.

At this point, I believe you have a deeper understanding of "what is the implementation principle of Linux mutex lock". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.