/*
doc: <routine name="rt_processor_new_private_queue" return_type="int" export="shared">
doc: <summary> Create a new private queue whose supplier is this processor. </summary>
doc: <param name="self" type="struct rt_processor*"> The processor object. Must not be NULL. </param>
doc: <param name="result" type="struct rt_private_queue**"> A pointer to the location where the result shall be stored. Must not be NULL. </param>
doc: <return> T_OK on success. T_NO_MORE_MEMORY or a mutex creation error code when a resource could not be allocated. </return>
doc: <thread_safety> Safe. </thread_safety>
doc: <synchronization> None required. </synchronization>
doc: </routine>
*/
int rt_processor_new_private_queue (struct rt_processor* self, struct rt_private_queue** result)
{
int error = T_OK;
struct rt_private_queue* l_queue = NULL;
REQUIRE ("self_not_nul", self);
REQUIRE ("result_not_null", result);
l_queue = (struct rt_private_queue*) malloc (sizeof (struct rt_private_queue));
if (l_queue) {
error = rt_private_queue_init (l_queue, self);
if (T_OK == error) {
RT_TRACE (eif_pthread_mutex_lock (self->generated_private_queues_mutex));
error = private_queue_list_t_extend (&self->generated_private_queues, l_queue);
RT_TRACE (eif_pthread_mutex_unlock (self->generated_private_queues_mutex));
}
if (T_OK == error) {
*result = l_queue;
} else {
/* An error occured. Free allocated resources and return. */
rt_private_queue_deinit (l_queue);
free (l_queue);
}
} else {
error = T_NO_MORE_MEMORY;
}
return error;
}
/*
doc: <routine name="rt_processor_publish_wait_condition" return_type="void" export="shared">
doc: <summary> Notify all processors in the 'self->wait_condition_subscribers' vector that a wait condition has changed. </summary>
doc: <param name="self" type="struct rt_processor*"> The processor with the subscribers list. Must not be NULL. </param>
doc: <thread_safety> Not safe. </thread_safety>
doc: <synchronization> The feature rt_processor_subscribe_wait_condition must only be called when the thread executing 'self' is synchronized with a client.
doc: This ensures that rt_publish_wait_condition cannot be executed at the same time. </synchronization>
doc: </routine>
*/
rt_shared void rt_processor_publish_wait_condition (struct rt_processor* self)
{
struct subscriber_list_t* subscribers = NULL;
REQUIRE ("self_not_null", self);
subscribers = &self->wait_condition_subscribers;
while (0 != subscriber_list_t_count(subscribers)) {
struct rt_processor* item = subscriber_list_t_last (subscribers);
subscriber_list_t_remove_last (subscribers);
if (item) {
/* Lock the registered processor's condition variable mutex. */
RT_TRACE (eif_pthread_mutex_lock (item->wait_condition_mutex));
/* Send a signal. */
RT_TRACE (eif_pthread_cond_signal (item->wait_condition));
/* Release the lock. */
RT_TRACE (eif_pthread_mutex_unlock (item->wait_condition_mutex));
}
}
}
/*
doc: <routine name="rt_request_group_lock" return_type="void" export="shared">
doc: <summary> Lock all processors in the request group. </summary>
doc: <param name="self" type="struct rt_request_group*"> The request group struct. Must not be NULL. </param>
doc: <thread_safety> Not safe. </thread_safety>
doc: <synchronization> None. </synchronization>
doc: </routine>
*/
rt_shared void rt_request_group_lock (struct rt_request_group* self)
{
size_t i, l_count = rt_request_group_count (self);
REQUIRE ("self_not_null", self);
REQUIRE ("not_locked", !self->is_locked);
/* We first need to sort the array based on the ID of the processor.
* At a global scale, this avoids deadlocks and enables the
* "atomic locking" guarantee of multiple arguments. */
if (!self->is_sorted) {
/* The array is usually very small (1 to 5 items), so having
* lightweight bubblesort algorithm is probably most efficient. */
bubble_sort (self->area, self->count);
self->is_sorted = 1;
}
/* Temporarily lock the queue-of-queue of all suppliers. */
for (i = 0; i < l_count; ++i) {
struct rt_processor* l_supplier = rt_request_group_item (self, i)->supplier;
RT_TRACE (eif_pthread_mutex_lock (l_supplier->queue_of_queues_mutex));
}
/* Add all private queues to the queue-of-queues */
for (i = 0; i < l_count; ++i) {
rt_private_queue_lock (rt_request_group_item (self, i), self->client);
}
/* Release the queue-of-queue locks. */
for (i = 0; i < l_count; ++i) {
struct rt_processor* l_supplier = rt_request_group_item (self, i)->supplier;
RT_TRACE (eif_pthread_mutex_unlock (l_supplier->queue_of_queues_mutex));
}
/* Synchronize with all passive processors. */
for (i=0; i < l_count; ++i) {
struct rt_private_queue* l_queue = rt_request_group_item (self, i);
if (l_queue->supplier->is_passive_region) {
rt_private_queue_synchronize (l_queue, self->client);
}
}
self->is_locked = 1;
ENSURE ("sorted", self->is_sorted);
ENSURE ("locked", self->is_locked);
}
int print_err_msg (FILE *err, char *StrFmt, ...)
{
va_list ap;
int r;
FILE *exception_saved;
char saved_cwd [PATH_MAX + 1];
eif_show_console ();
/* Write error to `err'. */
va_start (ap, StrFmt);
r = vfprintf (err, StrFmt, ap);
va_end (ap);
/* Now try to write error into `exception_trace.log' file */
#ifdef EIF_THREADS
/* FIXME: This is not thread safe at all. */
if (!eif_exception_trace_mutex) {
RT_TRACE(eif_pthread_mutex_create(&eif_exception_trace_mutex));
}
if (eif_exception_trace_mutex) {
RT_TRACE(eif_pthread_mutex_lock(eif_exception_trace_mutex));
}
#endif
getcwd(saved_cwd, PATH_MAX);
chdir (starting_working_directory);
/* If we are not allowed to write the exception, we don't do it */
if ((exception_saved = fopen( "exception_trace.log", "at" )) != NULL) {
va_start (ap, StrFmt);
r = vfprintf (exception_saved, StrFmt, ap);
va_end (ap);
fclose (exception_saved);
}
chdir (saved_cwd);
#ifdef EIF_THREADS
if (eif_exception_trace_mutex) {
RT_TRACE(eif_pthread_mutex_unlock(eif_exception_trace_mutex));
}
#endif
return r;
}
/*
doc: <routine name="rt_request_group_wait" return_type="int" export="shared">
doc: <summary>
doc: Release all locks and wait for a change notification from any processor in the group.
doc: This feature is usually called after a wait condition fails.
doc: It can only be called when the request group is locked.
doc: Note: The wait() operation is blocking! </summary>
doc: <param name="self" type="struct rt_request_group*"> The request group struct. Must not be NULL. </param>
doc: <return> T_OK on success. T_NO_MORE_MEMORY if memory allocation fails, in which case the request group remains locked. </return>
doc: <thread_safety> Not safe. </thread_safety>
doc: <synchronization> None. </synchronization>
doc: <fixme> Instead of unlocking normally after the wait condition, we could have a special 'unlock-after-wait-condition-failure'.
doc: That way we can avoid sending unnecessary notifications after the evaluation of a wait condition. </fixme>
doc: </routine>
*/
rt_shared int rt_request_group_wait (struct rt_request_group* self)
{
size_t i, l_count = rt_request_group_count (self);
struct rt_processor* l_client = self->client;
int error = T_OK;
REQUIRE ("self_not_null", self);
REQUIRE ("sorted", self->is_sorted);
REQUIRE ("locked", self->is_locked);
/* Register the current client with the suppliers, such that we
* can later get a notification if a wait condition may have changed. */
for (i = 0; i < l_count; ++i) {
struct rt_private_queue* l_queue = rt_request_group_item (self, i);
/* We only register on queues which are currently synchronized.
* Those are the ones that have executed a query during the wait
* condition, and thus the only ones that matter.
* Moreover, because the suppliers are currently synchronized, we
* know that they cannot access their notification queue at the
* moment, so we can safely modify the list from this thread. */
if (rt_private_queue_is_synchronized (l_queue)) {
error = rt_private_queue_register_wait (l_queue, l_client);
/* We bail out if we can't register for a wait condition change. */
if (error != T_OK) {
return error;
}
}
}
/* Inform the GC that we're about to be blocked. */
EIF_ENTER_C;
/* Before we unlock the synchronized queues, we have to acquire the
* lock to our condition variable mutex. This has to happen before
* rt_request_group_unlock to avoid missed signals. */
RT_TRACE (eif_pthread_mutex_lock (l_client->wait_condition_mutex));
/* Release the locks on the suppliers. After this statement they can
* execute calls from other processors and signal back a wait condition
* change. If we wouldn't hold the lock acquired in the previous step,
* we might miss those signals and thus remain stuck in a wait condition
* forever. */
rt_request_group_unlock (self);
/* Now we perform the blocking wait on our condition.
* This also releases the mutex, such that our suppliers may send signals to it.
* Note: Usually these wait operations are performed inside a loop that checks whether
* the wait condition became true. Our loop is compiler-generated however,
* that's why we don't see it here. */
RT_TRACE (eif_pthread_cond_wait (l_client->wait_condition, l_client->wait_condition_mutex));
/* After the wakeup signal, we can release the mutex.
* We're not interested in any further signals, as we re-register anyway if the
* wait condition fails again. */
RT_TRACE (eif_pthread_mutex_unlock (l_client->wait_condition_mutex));
/* Synchronize with the GC again. */
EIF_EXIT_C;
RTGC;
/* Note: We do not clean up the registrations here, because it would involve
* unnecessary locking and a risk of deadlocks. Instead, the suppliers delete
* our registration during notification, and the GC will clean up any leftover registrations. */
ENSURE ("not_locked", !self->is_locked);
return error;
}