According to the C11 and C++11 memory models only a read-modify-write
operation guarantees that we read the last value written in modification
order. Avoid the sequential consistent thread fence and instead use the
inter-processor interrupt to set the thread dispatch necessary
indicator.
Move the writes to Thread_Control::current_priority and
Thread_Control::real_priority into _Thread_Change_priority() under the
protection of the thread lock. Add a filter function to
_Thread_Change_priority() to enable specialized variants.
Avoid race conditions during a thread priority restore with the new
Thread_Control::priority_restore_hint for an important average case
optimizations used by priority inheritance mutexes.
Update #2273.
Account for priority changes of threads executing in a foreign
partition. Exchange idle threads in case a victim node uses an idle
thread and the new scheduled node needs an idle thread.
Make <rtems/score/atomic.h> available for all RTEMS configurations. Use
inline functions instead of macros. Use ISR disable/enable on
uni-processor configurations to ensure atomicity.
Update #2273.
Do not supsend self while waiting for termination since the
rtems_task_delete() may take place while the rtems_task_suspend() waits
for the Giant lock preventing delivery of the inter-processor interrupt.
The result is a suspended and terminated thread (this is a valid state,
but leads in this case to a test failure).
The previous timeout handling was flawed. In case a waiting thread
helped out the owner could use the scheduler node indefinitely long.
Update the resource tree in _MRSP_Timeout() to avoid this issue.
Bug reported by Luca Bonato.
Ensure that scheduler nodes in the SCHEDULER_HELP_ACTIVE_OWNER or
SCHEDULER_HELP_ACTIVE_RIVAL helping state are always
SCHEDULER_SMP_NODE_READY or SCHEDULER_SMP_NODE_SCHEDULED to ensure the
MrsP protocol properties.
New test case for smptests/smpmrsp01.
Fix _Scheduler_Block_node() in case the node is in the
SCHEDULER_HELP_ACTIVE_RIVAL helping state. For example a
rtems_task_suspend() on a task waiting for a MrsP semaphore.
Fix _Scheduler_Unblock_node() in case the node is in the
SCHEDULER_SMP_NODE_READY state. For example a rtems_task_resume() on a
task owning or waiting for a MrsP semaphore.
