WORKQUEUE(9) BSD Kernel Developer's Manual WORKQUEUE(9)NAMEworkqueue — 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 argu‐
ments:
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 frame‐
work.
workqueue_destroy() destroys a workqueue and frees associated resources.
The caller should ensure that the workqueue has no work enqueued before‐
hand.
RETURN VALUESworkqueue_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 ALSOcallout(9), condvar(9), kthread(9), softint(9)BSD October 24, 2011 BSD
