--- cpukit/include/rtems/score/threadq.h | 44 ++++++++++++++++++------ cpukit/include/rtems/score/threadqimpl.h | 17 +++++++++ 2 files changed, 51 insertions(+), 10 deletions(-)
diff --git a/cpukit/include/rtems/score/threadq.h b/cpukit/include/rtems/score/threadq.h index 10476888d4..0362f84c98 100644 --- a/cpukit/include/rtems/score/threadq.h +++ b/cpukit/include/rtems/score/threadq.h @@ -406,6 +406,7 @@ typedef struct _Thread_queue_Heads { } Thread_queue_Heads; struct Thread_queue_Queue { +#if defined(RTEMS_SMP) /** * @brief Lock to protect this thread queue. * @@ -418,7 +419,6 @@ struct Thread_queue_Queue { * @see _Thread_queue_Acquire(), _Thread_queue_Acquire_critical() and * _Thread_queue_Release(). */ -#if defined(RTEMS_SMP) SMP_ticket_lock_Control Lock; #endif @@ -517,37 +517,61 @@ typedef Thread_Control *( *Thread_queue_First_operation )( ); /** - * @brief Thread queue operations. + * @brief The thread queue operations are used to implement the addition and + * removal of threads to and from a thread queue and related tasks. + * + * The standard thread queue operation variants are: + * + * * ::_Thread_queue_Operations_default + * + * * ::_Thread_queue_Operations_FIFO + * + * * ::_Thread_queue_Operations_priority + * + * * ::_Thread_queue_Operations_priority_inherit * * @see _Thread_wait_Set_operations(). */ struct Thread_queue_Operations { /** - * @brief Thread queue priority actions operation. + * @brief This operation performs the thread queue priority actions. + * + * Priority actions are produced and processed during enqueue, extract, and + * surrender operations. */ Thread_queue_Priority_actions_operation priority_actions; /** - * @brief Thread queue enqueue operation. - * - * Called by object routines to enqueue the thread. + * @brief This operation is used to enqueue the thread on the thread queue. */ Thread_queue_Enqueue_operation enqueue; /** - * @brief Thread queue extract operation. + * @brief This operation is used to extract the thread from the thread queue. * - * Called by object routines to extract a thread from a thread queue. + * The extract operation is intended for timeouts, thread restarts, and + * thread cancellation. The surrender operation should be used to dequeue a + * thread from the thread queue. */ Thread_queue_Extract_operation extract; /** - * @brief Thread queue surrender operation. + * @brief This operation is used to dequeue the thread from the thread queue + * and optionally surrender the thread queue from a previous owner. + * + * In addition to the optional surrender, there is a subtle difference + * between the extract and dequeue of a thread from a thread queue. In SMP + * configurations, FIFO fairness across schedulers for priority queues is + * only ensured for the dequeue operation and not for the extract operation. */ Thread_queue_Surrender_operation surrender; /** - * @brief Thread queue first operation. + * @brief This operation returns the first thread on the thread queue. + * + * This operation shall be called only when the thread queue contains at + * least one thread. Use ::Thread_queue_Queue::heads to determine if a + * thread queue is empty. */ Thread_queue_First_operation first; }; diff --git a/cpukit/include/rtems/score/threadqimpl.h b/cpukit/include/rtems/score/threadqimpl.h index 33cdb3058d..5d3edaf9e0 100644 --- a/cpukit/include/rtems/score/threadqimpl.h +++ b/cpukit/include/rtems/score/threadqimpl.h @@ -1396,12 +1396,29 @@ typedef struct { Wait_queue.Queue \ ) +/** + * @brief The default thread queue operations are used when a thread is not + * enqueued on a thread queue. + */ extern const Thread_queue_Operations _Thread_queue_Operations_default; +/** + * @brief The FIFO thread queue operations are used when a thread is enqueued + * on a thread queue and provide FIFO ordering of enqueued threads. + */ extern const Thread_queue_Operations _Thread_queue_Operations_FIFO; +/** + * @brief The FIFO thread queue operations are used when a thread is enqueued + * on a thread queue and provide priority ordering of enqueued threads. + */ extern const Thread_queue_Operations _Thread_queue_Operations_priority; +/** + * @brief The FIFO thread queue operations are used when a thread is enqueued + * on a thread queue and provide priority ordering of enqueued threads with + * support for priority inheritance. + */ extern const Thread_queue_Operations _Thread_queue_Operations_priority_inherit; /** -- 2.26.2 _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel