createworkqueue

Createworkqueue is a Linux kernel API function used to create a new workqueue, a pool of kernel worker threads that can execute deferred work items asynchronously. The function returns a pointer to a workqueue_struct on success or NULL on failure. The created queue is identified by the name passed as an argument, which helps with debugging and tracing.

The typical prototype is struct workqueue_struct *create_workqueue(const char *name); After creation, code can schedule work onto the queue using the standard work item interfaces, such as queue_work(struct workqueue_struct *wq, struct work_struct *work) for immediate execution or queue_delayed_work for delayed execution. Work items are defined with struct work_struct or delayed_work and are initialized with macros like INIT_WORK or INIT_DELAYED_WORK. When the work is complete, resources associated with the work item can be reclaimed, and synchronization can be performed by flushing the queue with functions like flush_workqueue or by awaiting completion of scheduled work.

Destroying the queue is done with destroy_workqueue(struct workqueue_struct *wq) to free resources when the queue is no longer needed. It is important to ensure that all queued work has completed or has been flushed before destroying the queue to avoid use-after-free problems.

In modern Linux kernels, alloc_workqueue is preferred for creating workqueues because it offers more control over the pool, including the number of active workers and various behavior flags. create_workqueue remains part of compatibility interfaces in some kernel trees, but developers are encouraged to migrate to alloc_workqueue for new code. Overall, create_workqueue provides a mechanism to defer work to kernel threads in a controlled, named pool, improving responsiveness by avoiding long-running work in immediate call contexts.