From b8a5abf3fafa9df7cc0354c0ada6192c38e78354 Mon Sep 17 00:00:00 2001 From: Sebastian Huber Date: Thu, 26 Feb 2015 10:33:36 +0100 Subject: score: Update _Thread_Heir only if necessary 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. --- cpukit/score/include/rtems/score/schedulerimpl.h | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'cpukit/score/include') diff --git a/cpukit/score/include/rtems/score/schedulerimpl.h b/cpukit/score/include/rtems/score/schedulerimpl.h index 31ae6d184d..7bf4038b5e 100644 --- a/cpukit/score/include/rtems/score/schedulerimpl.h +++ b/cpukit/score/include/rtems/score/schedulerimpl.h @@ -314,6 +314,9 @@ RTEMS_INLINE_ROUTINE void _Scheduler_Unblock( Thread_Control *the_thread ) * must ensure that the priority value actually changed and is not equal to the * current priority value. * + * The operation must update the heir and thread dispatch necessary variables + * in case the set of scheduled threads changes. + * * @param[in] the_thread The thread changing its priority. * @param[in] new_priority The new thread priority. * @param[in] prepend_it In case this is true, then enqueue the thread as the @@ -630,16 +633,16 @@ bool _Scheduler_Set_affinity( #endif /* defined(__RTEMS_HAVE_SYS_CPUSET_H__) */ RTEMS_INLINE_ROUTINE void _Scheduler_Update_heir( - Thread_Control *heir, - bool force_dispatch + Thread_Control *new_heir, + bool force_dispatch ) { - Thread_Control *executing = _Thread_Executing; - - _Thread_Heir = heir; + Thread_Control *heir = _Thread_Heir; - if ( executing != heir && ( force_dispatch || executing->is_preemptible ) ) + if ( heir != new_heir && ( heir->is_preemptible || force_dispatch ) ) { + _Thread_Heir = new_heir; _Thread_Dispatch_necessary = true; + } } RTEMS_INLINE_ROUTINE void _Scheduler_Generic_block( -- cgit v1.2.3