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score: Fix blocking message queue receive

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In order to ensure FIFO fairness across schedulers, the thread queue
surrender operation must be used to dequeue a thread from the thread
queue.  The thread queue extract operation is intended for timeouts.

Add _Thread_queue_Resume() which may be used to make extracted or
surrendered threads ready again.

Remove the now unused _Thread_queue_Extract_critical() function.

Close #4509.
This commit is contained in:
Sebastian Huber
2021-09-01 20:24:57 +02:00
parent 9c0591f12d
commit d9249c9bff
4 changed files with 62 additions and 82 deletions
Download Patch File Download Diff File Expand all files Collapse all files
cpukit/include/rtems/score/coremsgimpl.h
+12 -8
View File
@@ -616,7 +616,8 @@ RTEMS_INLINE_ROUTINE Thread_Control *_CORE_message_queue_Dequeue_receiver(
Thread_queue_Context *queue_context
)
{
Thread_Control *the_thread;
Thread_queue_Heads *heads;
Thread_Control *the_thread;
/*
* If there are pending messages, then there can't be threads
@@ -634,14 +635,18 @@ RTEMS_INLINE_ROUTINE Thread_Control *_CORE_message_queue_Dequeue_receiver(
* There must be no pending messages if there is a thread waiting to
* receive a message.
*/
the_thread = _Thread_queue_First_locked(
&the_message_queue->Wait_queue,
the_message_queue->operations
);
if ( the_thread == NULL ) {
heads = the_message_queue->Wait_queue.Queue.heads;
if ( heads == NULL ) {
return NULL;
}
the_thread = ( *the_message_queue->operations->surrender )(
&the_message_queue->Wait_queue.Queue,
heads,
NULL,
queue_context
);
*(size_t *) the_thread->Wait.return_argument = size;
the_thread->Wait.count = (uint32_t) submit_type;
@@ -651,9 +656,8 @@ RTEMS_INLINE_ROUTINE Thread_Control *_CORE_message_queue_Dequeue_receiver(
size
);
_Thread_queue_Extract_critical(
_Thread_queue_Resume(
&the_message_queue->Wait_queue.Queue,
the_message_queue->operations,
the_thread,
queue_context
);
cpukit/include/rtems/score/threadqimpl.h
+13 -46
View File
@@ -975,56 +975,23 @@ void _Thread_queue_Unblock_critical(
);
/**
* @brief Extracts the thread from the thread queue and unblocks it.
* @brief Resumes the extracted or surrendered thread.
*
* The caller must be the owner of the thread queue lock. This function will
* release the thread queue lock and restore the default thread lock. Thread
* dispatching is disabled before the thread queue lock is released and an
* unblock is necessary. Thread dispatching is enabled once the sequence to
* unblock the thread is complete. This makes it possible to use the thread
* queue lock to protect the state of objects embedding the thread queue and
* directly enter _Thread_queue_Extract_critical() to finalize an operation in
* case a waiting thread exists.
* This function makes the thread ready again. If necessary, the thread is
* unblocked and its thread timer removed.
*
* @code
* #include <rtems/score/threadqimpl.h>
* The thread shall have been extracted from the thread queue or surrendered by
* the thread queue right before the call to this function. The caller shall
* be the owner of the thread queue lock.
*
* typedef struct {
* Thread_queue_Control Queue;
* Thread_Control *owner;
* } Mutex;
*
* void _Mutex_Release( Mutex *mutex )
* {
* Thread_queue_Context queue_context;
* Thread_Control *first;
*
* _Thread_queue_Context_initialize( &queue_context, NULL );
* _Thread_queue_Acquire( &mutex->Queue, queue_context );
*
* first = _Thread_queue_First_locked( &mutex->Queue );
* mutex->owner = first;
*
* if ( first != NULL ) {
* _Thread_queue_Extract_critical(
* &mutex->Queue.Queue,
* mutex->Queue.operations,
* first,
* &queue_context
* );
* }
* @endcode
*
* @param queue The actual thread queue.
* @param operations The thread queue operations.
* @param[in, out] the_thread The thread to extract.
* @param[in, out] queue_context The thread queue context of the lock acquire.
* @param queue is the actual thread queue.
* @param[in, out] the_thread is the thread to make ready and unblock.
* @param[in, out] queue_context is the thread queue context.
*/
void _Thread_queue_Extract_critical(
Thread_queue_Queue *queue,
const Thread_queue_Operations *operations,
Thread_Control *the_thread,
Thread_queue_Context *queue_context
void _Thread_queue_Resume(
Thread_queue_Queue *queue,
Thread_Control *the_thread,
Thread_queue_Context *queue_context
);
/**
cpukit/score/src/coremsgseize.c
+12 -8
View File
@@ -56,7 +56,8 @@ Status_Control _CORE_message_queue_Seize(
return STATUS_SUCCESSFUL;
#else
{
Thread_Control *the_thread;
Thread_queue_Heads *heads;
Thread_Control *the_thread;
/*
* There could be a thread waiting to send a message. If there
@@ -65,11 +66,8 @@ Status_Control _CORE_message_queue_Seize(
* NOTE: If we note that the queue was not full before this receive,
* then we can avoid this dequeue.
*/
the_thread = _Thread_queue_First_locked(
&the_message_queue->Wait_queue,
the_message_queue->operations
);
if ( the_thread == NULL ) {
heads = the_message_queue->Wait_queue.Queue.heads;
if ( heads == NULL ) {
_CORE_message_queue_Free_message_buffer(
the_message_queue,
the_message
@@ -78,6 +76,13 @@ Status_Control _CORE_message_queue_Seize(
return STATUS_SUCCESSFUL;
}
the_thread = ( *the_message_queue->operations->surrender )(
&the_message_queue->Wait_queue.Queue,
heads,
NULL,
queue_context
);
/*
* There was a thread waiting to send a message. This code
* puts the messages in the message queue on behalf of the
@@ -90,9 +95,8 @@ Status_Control _CORE_message_queue_Seize(
(size_t) the_thread->Wait.option,
(CORE_message_queue_Submit_types) the_thread->Wait.count
);
_Thread_queue_Extract_critical(
_Thread_queue_Resume(
&the_message_queue->Wait_queue.Queue,
the_message_queue->operations,
the_thread,
queue_context
);
cpukit/score/src/threadqenqueue.c
+25 -20
View File
@@ -7,9 +7,10 @@
* _Thread_queue_Deadlock_fatal(), _Thread_queue_Deadlock_status(),
* _Thread_queue_Do_dequeue(), _Thread_queue_Enqueue(),
* _Thread_queue_Enqueue_do_nothing_extra(), _Thread_queue_Enqueue_sticky(),
* _Thread_queue_Extract(), _Thread_queue_Extract_critical(),
* _Thread_queue_Extract_locked(), _Thread_queue_Path_acquire_critical(),
* _Thread_queue_Path_release_critical(), _Thread_queue_Surrender(),
* _Thread_queue_Extract(), _Thread_queue_Extract_locked(),
* _Thread_queue_Path_acquire_critical(),
* _Thread_queue_Path_release_critical(),
* _Thread_queue_Resume(),_Thread_queue_Surrender(),
* _Thread_queue_Surrender_sticky(), and _Thread_queue_Unblock_critical().
*/
@@ -604,28 +605,32 @@ void _Thread_queue_Unblock_critical(
}
}
void _Thread_queue_Extract_critical(
Thread_queue_Queue *queue,
const Thread_queue_Operations *operations,
Thread_Control *the_thread,
Thread_queue_Context *queue_context
void _Thread_queue_Resume(
Thread_queue_Queue *queue,
Thread_Control *the_thread,
Thread_queue_Context *queue_context
)
{
bool unblock;
unblock = _Thread_queue_Extract_locked(
queue,
operations,
the_thread,
queue_context
);
unblock = _Thread_queue_Make_ready_again( the_thread );
_Thread_queue_Unblock_critical(
unblock,
queue,
the_thread,
&queue_context->Lock_context.Lock_context
);
if ( unblock ) {
Per_CPU_Control *cpu_self;
cpu_self = _Thread_queue_Dispatch_disable( queue_context );
_Thread_queue_Queue_release(
queue, &queue_context->Lock_context.Lock_context
);
_Thread_Remove_timer_and_unblock( the_thread, queue );
_Thread_Dispatch_enable( cpu_self );
} else {
_Thread_queue_Queue_release(
queue, &queue_context->Lock_context.Lock_context
);
}
}
void _Thread_queue_Extract( Thread_Control *the_thread )