WORKQUEUE(9)						   BSD Kernel Developer's Manual					      WORKQUEUE(9)

NAME

     workqueue -- simple do-it-in-thread-context framework

SYNOPSIS

     #include <sys/workqueue.h>

     int
     workqueue_create(struct workqueue **wqp, const char *name, void (*func)(struct work *, void *), void *arg, pri_t prio, int ipl, int flags);

     void
     workqueue_enqueue(struct workqueue *wq, struct work *wk, struct cpu_info *ci);

     void
     workqueue_destroy(struct workqueue *wq);

DESCRIPTION

     The workqueue utility routines are provided to defer work which is needed to be processed in a thread context.

     workqueue_create() creates a workqueue.  It takes the following arguments:

     wqp    Specify where to store the created workqueue.

     name   The name of the workqueue.

     func   The function to be called for each work.

     arg    An argument to be passed as a second argument of func.

     prio   The priority level for the worker threads.

     ipl    The highest IPL at which this workqueue is used.

     flags  The value of 0 indicates a standard create operation, however the following flags may be bitwise ORed together:

	    WQ_MPSAFE  Specifies that the workqueue is multiprocessor safe and does its own locking, otherwise the kernel lock will be held while
		       work will be processed.

	    WQ_PERCPU  Specifies that the workqueue should have a separate queue for each CPU, thus the work could be enqueued on concrete CPUs.

     workqueue_enqueue() enqueues the work wk into the workqueue wq.

     If the WQ_PERCPU flag was set on workqueue creation, the ci argument may be used to specify the CPU on which the work should be enqueued.
     Also it may be NULL, then work will be enqueued on the current CPU.  If WQ_PERCPU flag was not set, ci must be NULL.

     The enqueued work will be processed in a thread context.  A work must not be enqueued again until the callback is called by the workqueue
     framework.

     workqueue_destroy() destroys a workqueue and frees associated resources.  The caller should ensure that the workqueue has no work enqueued
     beforehand.

RETURN VALUES

     workqueue_create() returns 0 on success.  Otherwise, it returns an errno(2).

CODE REFERENCES

     The workqueue subsystem is implemented within the file sys/kern/subr_workqueue.c.

SEE ALSO

     callout(9), condvar(9), kthread(9), softint(9)

BSD
								 October 24, 2011							       BSD