Chapter 33. Preventing resource overuse by using mutex

Mutual exclusion (mutex) algorithms are used to prevent processes simultaneously using a common resource. A fast user-space mutex (futex) is a tool that allows a user-space thread to claim a mutex without requiring a context switch to kernel space, provided the mutex is not already held by another thread.

When you initialize a pthread_mutex_t object with the standard attributes, a private, non-recursive, non-robust, and non-priority inheritance-capable mutex is created. This object does not provide any of the benfits provided by the pthreads API and the RHEL for Real Time kernel.

To benefit from the pthreads API and the RHEL for Real Time kernel, create a pthread_mutexattr_t object. This object stores the attributes defined for the futex.

To define any additional capabilities for the mutex, create a pthread_mutexattr_t object. This object stores the defined attributes for the futex. This is a basic safety procedure that you must always perform.

For more information about advanced mutex attributes, see Advanced mutex attributes.

When you initialize a pthread_mutex_t object with the standard attributes, a private, non-recursive, non-robust, and non-priority inheritance-capable mutex is created.

The following advanced mutex attributes can be stored in a mutex attribute object:

After the mutex has been created using the mutex attribute object, you can keep the attribute object to initialize more mutexes of the same type, or you can clean it up. The mutex is not affected in either case.