source: rtems/cpukit/score/src/schedulerpriorityyield.c @ 8568341

4.115
Last change on this file since 8568341 was 8568341, checked in by Sebastian Huber <sebastian.huber@…>, on 06/11/14 at 12:31:03

score: Need for help indicator for scheduler ops

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.

  • Property mode set to 100644
File size: 1.2 KB
Line 
1/**
2 *  @file
3 *
4 *  @brief Scheduler Priority Yield
5 *  @ingroup ScoreScheduler
6 */
7
8/*
9 *  Copyright (C) 2010 Gedare Bloom.
10 *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
11 *
12 *  The license and distribution terms for this file may be
13 *  found in the file LICENSE in this distribution or at
14 *  http://www.rtems.org/license/LICENSE.
15 */
16
17#if HAVE_CONFIG_H
18#include "config.h"
19#endif
20
21#include <rtems/score/schedulerpriorityimpl.h>
22#include <rtems/score/threadimpl.h>
23
24Scheduler_Void_or_thread _Scheduler_priority_Yield(
25  const Scheduler_Control *scheduler,
26  Thread_Control          *the_thread
27)
28{
29  Scheduler_priority_Node *node = _Scheduler_priority_Thread_get_node( the_thread );
30  Chain_Control *ready_chain = node->Ready_queue.ready_chain;
31
32  (void) scheduler;
33
34  if ( !_Chain_Has_only_one_node( ready_chain ) ) {
35    _Chain_Extract_unprotected( &the_thread->Object.Node );
36    _Chain_Append_unprotected( ready_chain, &the_thread->Object.Node );
37
38    if ( _Thread_Is_heir( the_thread ) ) {
39      _Thread_Heir = (Thread_Control *) _Chain_First( ready_chain );
40    }
41
42    _Thread_Dispatch_necessary = true;
43  } else if ( !_Thread_Is_heir( the_thread ) ) {
44    _Thread_Dispatch_necessary = true;
45  }
46
47  SCHEDULER_RETURN_VOID_OR_NULL;
48}
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