Commit 77ff5599e0 introduced a change in
the rtems_semaphore_create() behaviour for MrsP semaphores. The ceiling
priorities for all schedulers except the scheduler of the executing
thread are initialized to zero.
The thread priority is manifest in two independent areas. One area is
the user visible thread priority along with a potential thread queue.
The other is the scheduler. Currently, a thread priority update via
_Thread_Change_priority() first updates the user visble thread priority
and the thread queue, then the scheduler is notified if necessary. The
priority is passed to the scheduler via a local variable. A generation
counter ensures that the scheduler discards out-of-date priorities.
This use of a local variable ties the update in these two areas close
together. For later enhancements and the OMIP locking protocol
implementation we need more flexibility. Add a thread priority
information block to Scheduler_Node and synchronize priority value
updates via a sequence lock on SMP configurations.
Update #2556.
The _RBTree_Find() is no longer used in the score. Move it to sapi and
make it rtems_rbtree_find(). Move corresponding types and support
functions to sapi.
Use inline red-black tree insert. Do not use shifting priorities since
this is not supported by the thread queues. Due to the 32-bit
Priority_Control this currently limits the uptime to 49days with a 1ms
clock tick.
Update #2173.
Introduce map/unmap priority scheduler operations to map thread priority
values from/to the user domain to/from the scheduler domain. Use the
map priority operation to validate the thread priority. The EDF
schedulers use this new operation to distinguish between normal
priorities and priorities obtain through a job release.
Update #2173.
Update #2556.
Instead of lowering the priority in case the initial budget is consumed
raise the priority for each new period. Restore the normal priority
once the initial budget is consumed. This makes it later easier to
combine the high priority phase with temporary priority boosts (e.g. via
priority ceiling and inheritance).
Use the thread lock to protect the POSIX thread attributes instead of
the thread state lock. This makes it easier to change the thread
priority and keep the POSIX attributes consistent.
Fixes a false positive use of uninitialized variable warning.
Accept all priority values in pthread_mutexattr_setprioceiling(). This
is in line with POSIX and FreeBSD. The priority is validated in
pthread_mutex_init(). Validate the priority only for priority ceiling
mutexes.
The RTEMS print user need to know nothing about a particular printer
implementation. In particular get rid of the <stdio.h> include which
would be visible via <rtems.h>.
