60 lines
2.1 KiB
C
60 lines
2.1 KiB
C
/*
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* workq.h
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*
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* This header file defines the interfaces for a "work queue"
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* manager. A "manager object" is created with several
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* parameters, including the required size of a work queue
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* entry, the maximum desired degree of parallelism (number of
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* threads to service the queue), and the address of an
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* execution engine routine.
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*
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* The application requests a work queue entry from the manager,
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* fills in the application-specific fields, and returns it to
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* the queue manager for processing. The manager will create a
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* new thread to service the queue if all current threads are
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* busy and the maximum level of parallelism has not yet been
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* reached.
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*
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* The manager will dequeue items and present them to the
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* processing engine until the queue is empty; at that point,
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* processing threads will begin to shut down. (They will be
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* restarted when work appears.)
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*/
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#include <pthread.h>
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/*
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* Structure to keep track of work queue requests.
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*/
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typedef struct workq_ele_tag {
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struct workq_ele_tag *next;
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void *data;
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} workq_ele_t;
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/*
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* Structure describing a work queue.
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*/
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typedef struct workq_tag {
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pthread_mutex_t mutex;
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pthread_cond_t cv; /* wait for work */
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pthread_attr_t attr; /* create detached threads */
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workq_ele_t *first, *last; /* work queue */
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int valid; /* set when valid */
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int quit; /* set when workq should quit */
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int parallelism; /* number of threads required */
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int counter; /* current number of threads */
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int idle; /* number of idle threads */
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void (*engine)(void *arg); /* user engine */
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} workq_t;
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#define WORKQ_VALID 0xdec1992
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/*
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* Define work queue functions
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*/
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extern int workq_init (
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workq_t *wq,
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int threads, /* maximum threads */
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void (*engine)(void *)); /* engine routine */
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extern int workq_destroy (workq_t *wq);
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extern int workq_add (workq_t *wq, void *data);
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