void _Region_Process_queue(
Region_Control *the_region
)
{
Thread_Control *the_thread;
void *the_segment;
/*
* Switch from using the memory allocation mutex to using a
* dispatching disabled critical section. We have to do this
* because this thread may unblock one or more threads that were
* waiting on memory.
*
* NOTE: Be sure to disable dispatching before unlocking the mutex
* since we do not want to open a window where a context
* switch could occur.
*/
_Thread_Disable_dispatch();
_RTEMS_Unlock_allocator();
/*
* NOTE: The following loop is O(n) where n is the number of
* threads whose memory request is satisfied.
*/
for ( ; ; ) {
the_thread = _Thread_queue_First( &the_region->Wait_queue );
if ( the_thread == NULL )
break;
the_segment = (void **) _Region_Allocate_segment(
the_region,
the_thread->Wait.count
);
if ( the_segment == NULL )
break;
*(void **)the_thread->Wait.return_argument = the_segment;
the_region->number_of_used_blocks += 1;
_Thread_queue_Extract( &the_region->Wait_queue, the_thread );
the_thread->Wait.return_code = RTEMS_SUCCESSFUL;
}
_Thread_Enable_dispatch();
}
rtems_status_code rtems_region_get_segment(
rtems_id id,
uintptr_t size,
rtems_option option_set,
rtems_interval timeout,
void **segment
)
{
rtems_status_code status;
Region_Control *the_region;
if ( segment == NULL ) {
return RTEMS_INVALID_ADDRESS;
}
*segment = NULL;
if ( size == 0 ) {
return RTEMS_INVALID_SIZE;
}
the_region = _Region_Get_and_lock( id );
if ( the_region == NULL ) {
return RTEMS_INVALID_ID;
}
if ( size > the_region->maximum_segment_size ) {
status = RTEMS_INVALID_SIZE;
} else {
void *the_segment;
the_segment = _Region_Allocate_segment( the_region, size );
if ( the_segment != NULL ) {
*segment = the_segment;
status = RTEMS_SUCCESSFUL;
} else if ( _Options_Is_no_wait( option_set ) ) {
status = RTEMS_UNSATISFIED;
} else {
Thread_queue_Context queue_context;
Thread_Control *executing;
_Thread_queue_Context_initialize( &queue_context );
_Thread_queue_Acquire( &the_region->Wait_queue, &queue_context );
executing = _Thread_Executing;
executing->Wait.count = size;
executing->Wait.return_argument = segment;
/* FIXME: This is a home grown condition variable */
_Thread_queue_Context_set_thread_state(
&queue_context,
STATES_WAITING_FOR_SEGMENT
);
_Thread_queue_Context_set_timeout_ticks( &queue_context, timeout );
_Thread_queue_Context_set_enqueue_callout(
&queue_context,
_Region_Enqueue_callout
);
_Thread_queue_Enqueue(
&the_region->Wait_queue.Queue,
the_region->wait_operations,
executing,
&queue_context
);
return _Status_Get_after_wait( executing );
}
}
_Region_Unlock( the_region );
return status;
}
rtems_status_code rtems_region_get_segment(
rtems_id id,
uintptr_t size,
rtems_option option_set,
rtems_interval timeout,
void **segment
)
{
Thread_Control *executing;
Objects_Locations location;
rtems_status_code return_status;
Region_Control *the_region;
void *the_segment;
if ( !segment )
return RTEMS_INVALID_ADDRESS;
*segment = NULL;
if ( size == 0 )
return RTEMS_INVALID_SIZE;
_RTEMS_Lock_allocator();
executing = _Thread_Get_executing();
the_region = _Region_Get( id, &location );
switch ( location ) {
case OBJECTS_LOCAL:
if ( size > the_region->maximum_segment_size )
return_status = RTEMS_INVALID_SIZE;
else {
_Region_Debug_Walk( the_region, 1 );
the_segment = _Region_Allocate_segment( the_region, size );
_Region_Debug_Walk( the_region, 2 );
if ( the_segment ) {
the_region->number_of_used_blocks += 1;
*segment = the_segment;
return_status = RTEMS_SUCCESSFUL;
} else if ( _Options_Is_no_wait( option_set ) ) {
return_status = RTEMS_UNSATISFIED;
} else {
/*
* Switch from using the memory allocation mutex to using a
* dispatching disabled critical section. We have to do this
* because this thread is going to block.
*/
/* FIXME: Lock order reversal */
_Thread_Disable_dispatch();
_RTEMS_Unlock_allocator();
executing->Wait.queue = &the_region->Wait_queue;
executing->Wait.id = id;
executing->Wait.count = size;
executing->Wait.return_argument = segment;
_Thread_queue_Enter_critical_section( &the_region->Wait_queue );
_Thread_queue_Enqueue(
&the_region->Wait_queue,
executing,
timeout
);
_Objects_Put( &the_region->Object );
return (rtems_status_code) executing->Wait.return_code;
}
}
break;
#if defined(RTEMS_MULTIPROCESSING)
case OBJECTS_REMOTE: /* this error cannot be returned */
break;
#endif
case OBJECTS_ERROR:
default:
return_status = RTEMS_INVALID_ID;
break;
}
_RTEMS_Unlock_allocator();
return return_status;
}
rtems_status_code rtems_region_get_segment(
Objects_Id id,
uint32_t size,
rtems_option option_set,
rtems_interval timeout,
void **segment
)
{
register Region_Control *the_region;
Objects_Locations location;
Thread_Control *executing;
void *the_segment;
if ( !segment )
return RTEMS_INVALID_ADDRESS;
*segment = NULL;
if ( size == 0 )
return RTEMS_INVALID_SIZE;
_RTEMS_Lock_allocator();
executing = _Thread_Executing;
the_region = _Region_Get( id, &location );
switch ( location ) {
case OBJECTS_REMOTE: /* this error cannot be returned */
_RTEMS_Unlock_allocator();
return RTEMS_INTERNAL_ERROR;
case OBJECTS_ERROR:
_RTEMS_Unlock_allocator();
return RTEMS_INVALID_ID;
case OBJECTS_LOCAL:
if ( size > the_region->maximum_segment_size ) {
_RTEMS_Unlock_allocator();
return RTEMS_INVALID_SIZE;
}
_Region_Debug_Walk( the_region, 1 );
the_segment = _Region_Allocate_segment( the_region, size );
_Region_Debug_Walk( the_region, 2 );
if ( the_segment ) {
the_region->number_of_used_blocks += 1;
_RTEMS_Unlock_allocator();
*segment = the_segment;
return RTEMS_SUCCESSFUL;
}
if ( _Options_Is_no_wait( option_set ) ) {
_RTEMS_Unlock_allocator();
return RTEMS_UNSATISFIED;
}
/*
* Switch from using the memory allocation mutex to using a
* dispatching disabled critical section. We have to do this
* because this thread is going to block.
*/
_Thread_Disable_dispatch();
_RTEMS_Unlock_allocator();
executing->Wait.queue = &the_region->Wait_queue;
executing->Wait.id = id;
executing->Wait.count = size;
executing->Wait.return_argument = segment;
_Thread_queue_Enter_critical_section( &the_region->Wait_queue );
_Thread_queue_Enqueue( &the_region->Wait_queue, timeout );
_Thread_Enable_dispatch();
return (rtems_status_code) executing->Wait.return_code;
}
return RTEMS_INTERNAL_ERROR; /* unreached - only to remove warnings */
}
