diff options
Diffstat (limited to 'linuxthreads/queue.h')
-rw-r--r-- | linuxthreads/queue.h | 57 |
1 files changed, 25 insertions, 32 deletions
diff --git a/linuxthreads/queue.h b/linuxthreads/queue.h index 60039cce6e..fa8c5d861d 100644 --- a/linuxthreads/queue.h +++ b/linuxthreads/queue.h @@ -14,49 +14,42 @@ /* Waiting queues */ -typedef struct _pthread_queue pthread_queue; +/* Waiting queues are represented by lists of thread descriptors + linked through their p_nextwaiting field. The lists are kept + sorted by decreasing priority, and then decreasing waiting time. */ -static inline void queue_init(pthread_queue * q) +static inline void enqueue(pthread_descr * q, pthread_descr th) { - q->head = q->tail = NULL; -} - -static inline void enqueue(pthread_queue * q, pthread_descr th) -{ - int prio; - pthread_descr * elt; - + int prio = th->p_priority; ASSERT(th->p_nextwaiting == NULL); - if (q->tail == NULL) { - q->head = th; - q->tail = th; - return; - } - prio = th->p_priority; - if (prio > 0) { - /* Insert in queue according to priority order */ - for (elt = &(q->head); *elt != NULL; elt = &((*elt)->p_nextwaiting)) { - if (prio > (*elt)->p_priority) { - th->p_nextwaiting = *elt; - *elt = th; - return; - } + for (; *q != NULL; q = &((*q)->p_nextwaiting)) { + if (prio > (*q)->p_priority) { + th->p_nextwaiting = *q; + *q = th; + return; } } - /* Priority is no greater than any thread in the queue. - Insert at end of queue */ - q->tail->p_nextwaiting = th; - q->tail = th; + *q = th; } -static inline pthread_descr dequeue(pthread_queue * q) +static inline pthread_descr dequeue(pthread_descr * q) { pthread_descr th; - th = q->head; + th = *q; if (th != NULL) { - q->head = th->p_nextwaiting; - if (q->head == NULL) q->tail = NULL; + *q = th->p_nextwaiting; th->p_nextwaiting = NULL; } return th; } + +static inline void remove_from_queue(pthread_descr * q, pthread_descr th) +{ + for (; *q != NULL; q = &((*q)->p_nextwaiting)) { + if (*q == th) { + *q = th->p_nextwaiting; + th->p_nextwaiting = NULL; + return; + } + } +} |