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* score: Update _Thread_Heir only if necessarySebastian Huber2015-03-051-0/+2
| | | | | | | | | | | | | | | | | | | | Previously, the _Thread_Heir was updated unconditionally in case a new heir was determined. The _Thread_Dispatch_necessary was only updated in case the executing thread was preemptible or an internal thread was unblocked. Change this to update the _Thread_Heir and _Thread_Dispatch_necessary only in case the currently selected heir thread is preemptible or a dispatch is forced. Move the schedule decision into the change priority operation and use the schedule operation only in rtems_task_mode() in case preemption is enabled or an ASR dispatch is necessary. This is a behaviour change. Previously, the RTEMS_NO_PREEMPT also prevented signal delivery in certain cases (not always). Now, signal delivery is no longer influenced by RTEMS_NO_PREEMPT. Since the currently selected heir thread is used to determine if a new heir is chosen, non-preemptible heir threads currently not executing now prevent a new heir. This may have an application impact, see change test tm04. Document this change in sp04. Update #2273.
* rbtree: Reduce RBTree_Control sizeSebastian Huber2014-07-151-1/+6
| | | | | | | | | | | | Remove compare function and is unique indicator from the control structure. Rename RBTree_Compare_function to RBTree_Compare. Rename rtems_rbtree_compare_function to rtems_rbtree_compare. Provide C++ compatible initializers. Add compare function and is unique indicator to _RBTree_Find(), _RBTree_Insert(), rtems_rbtree_find() and rtems_rbtree_insert(). Remove _RBTree_Is_unique() and rtems_rbtree_is_unique(). Remove compare function and is unique indicator from _RBTree_Initialize_empty() and rtems_rbtree_initialize_empty().
* score: Need for help indicator for scheduler opsSebastian Huber2014-07-081-1/+3
| | | | | | | | | | | | | Return a thread in need for help for the following scheduler operations - unblock, - change priority, and - yield. A thread in need for help is a thread that encounters a scheduler state change from scheduled to ready or a thread that cannot be scheduled in an unblock operation. Such a thread can ask threads which depend on resources owned by this thread for help.
* score: Rename *_Node_get() to *_Thread_get_node()Sebastian Huber2014-07-081-1/+1
| | | | | | This emphasizes that the scheduler node of a thread is returned and this is not a function working with scheduler nodes like the other *_Node_*() functions.
* score: Simplify _Thread_Change_priority()Sebastian Huber2014-05-151-0/+36
The function to change a thread priority was too complex. Simplify it with a new scheduler operation. This increases the average case performance due to the simplified logic. The interrupt disabled critical section is a bit prolonged since now the extract, update and enqueue steps are executed atomically. This should however not impact the worst-case interrupt latency since at least for the Deterministic Priority Scheduler this sequence can be carried out with a wee bit of instructions and no loops. Add _Scheduler_Change_priority() to replace the sequence of - _Thread_Set_transient(), - _Scheduler_Extract(), - _Scheduler_Enqueue(), and - _Scheduler_Enqueue_first(). Delete STATES_TRANSIENT, _States_Is_transient() and _Thread_Set_transient() since this state is now superfluous. With this change it is possible to get rid of the SCHEDULER_SMP_NODE_IN_THE_AIR state. This considerably simplifies the implementation of the new SMP locking protocols.