source: rtems/cpukit/score/src/schedulersimplechangepriority.c @ 99fc1d1d

5
Last change on this file since 99fc1d1d was b8a5abf, checked in by Sebastian Huber <sebastian.huber@…>, on 02/26/15 at 09:33:36

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.

  • Property mode set to 100644
File size: 1.1 KB
Line 
1/**
2 * @file
3 *
4 * @brief Removes a Thread from the Simple Queue
5 *
6 * @ingroup ScoreScheduler
7 */
8
9/*
10 *  COPYRIGHT (c) 2011.
11 *  On-Line Applications Research Corporation (OAR).
12 *
13 *  The license and distribution terms for this file may be
14 *  found in the file LICENSE in this distribution or at
15 *  http://www.rtems.org/license/LICENSE.
16 */
17
18#if HAVE_CONFIG_H
19#include "config.h"
20#endif
21
22#include <rtems/score/schedulersimpleimpl.h>
23
24Scheduler_Void_or_thread _Scheduler_simple_Change_priority(
25  const Scheduler_Control *scheduler,
26  Thread_Control          *the_thread,
27  Priority_Control         new_priority,
28  bool                     prepend_it
29)
30{
31  Scheduler_simple_Context *context =
32    _Scheduler_simple_Get_context( scheduler );
33
34  _Scheduler_simple_Extract( scheduler, the_thread );
35
36  if ( prepend_it ) {
37    _Scheduler_simple_Insert_priority_lifo( &context->Ready, the_thread );
38  } else {
39    _Scheduler_simple_Insert_priority_fifo( &context->Ready, the_thread );
40  }
41
42  _Scheduler_simple_Schedule_body( scheduler, the_thread, false );
43
44  SCHEDULER_RETURN_VOID_OR_NULL;
45}
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