source: rtems/cpukit/score/include/rtems/score/schedulerprioritysmp.h @ 864d3475

4.115
Last change on this file since 864d3475 was 5c3d250, checked in by Sebastian Huber <sebastian.huber@…>, on 07/04/14 at 12:34:23

score: Implement scheduler helping protocol

The following scheduler operations return a thread in need for help

  • 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.

Add a new ask for help scheduler operation. This operation is used by
_Scheduler_Ask_for_help() to help threads in need for help returned by
the operations mentioned above. This operation is also used by
_Scheduler_Thread_change_resource_root() in case the root of a resource
sub-tree changes. A use case is the ownership change of a resource.

In case it is not possible to schedule a thread in need for help, then
the corresponding scheduler node will be placed into the set of ready
scheduler nodes of the scheduler instance. Once a state change from
ready to scheduled happens for this scheduler node it may be used to
schedule the thread in need for help.

  • Property mode set to 100644
File size: 3.7 KB
Line 
1/**
2 * @file
3 *
4 * @ingroup ScoreSchedulerPrioritySMP
5 *
6 * @brief Deterministic Priority SMP Scheduler API
7 */
8
9/*
10 * Copyright (c) 2013-2014 embedded brains GmbH.  All rights reserved.
11 *
12 *  embedded brains GmbH
13 *  Dornierstr. 4
14 *  82178 Puchheim
15 *  Germany
16 *  <rtems@embedded-brains.de>
17 *
18 * The license and distribution terms for this file may be
19 * found in the file LICENSE in this distribution or at
20 * http://www.rtems.org/license/LICENSE.
21 */
22
23#ifndef _RTEMS_SCORE_SCHEDULERPRIORITYSMP_H
24#define _RTEMS_SCORE_SCHEDULERPRIORITYSMP_H
25
26#include <rtems/score/scheduler.h>
27#include <rtems/score/schedulerpriority.h>
28#include <rtems/score/schedulersmp.h>
29
30#ifdef __cplusplus
31extern "C" {
32#endif /* __cplusplus */
33
34/**
35 * @defgroup ScoreSchedulerPrioritySMP Deterministic Priority SMP Scheduler
36 *
37 * @ingroup ScoreSchedulerSMP
38 *
39 * This is an implementation of the global fixed priority scheduler (G-FP).  It
40 * uses one ready chain per priority to ensure constant time insert operations.
41 * The scheduled chain uses linear insert operations and has at most processor
42 * count entries.  Since the processor and priority count are constants all
43 * scheduler operations complete in a bounded execution time.
44 *
45 * The thread preempt mode will be ignored.
46 *
47 * @{
48 */
49
50/**
51 * @brief Scheduler context specialization for Deterministic Priority SMP
52 * schedulers.
53 */
54typedef struct {
55  Scheduler_SMP_Context    Base;
56  Priority_bit_map_Control Bit_map;
57  Chain_Control            Ready[ RTEMS_ZERO_LENGTH_ARRAY ];
58} Scheduler_priority_SMP_Context;
59
60/**
61 * @brief Scheduler node specialization for Deterministic Priority SMP
62 * schedulers.
63 */
64typedef struct {
65  /**
66   * @brief SMP scheduler node.
67   */
68  Scheduler_SMP_Node Base;
69
70  /**
71   * @brief The associated ready queue of this node.
72   */
73  Scheduler_priority_Ready_queue Ready_queue;
74} Scheduler_priority_SMP_Node;
75
76/**
77 * @brief Entry points for the Priority SMP Scheduler.
78 */
79#define SCHEDULER_PRIORITY_SMP_ENTRY_POINTS \
80  { \
81    _Scheduler_priority_SMP_Initialize, \
82    _Scheduler_default_Schedule, \
83    _Scheduler_priority_SMP_Yield, \
84    _Scheduler_priority_SMP_Block, \
85    _Scheduler_priority_SMP_Unblock, \
86    _Scheduler_priority_SMP_Change_priority, \
87    _Scheduler_priority_SMP_Ask_for_help, \
88    _Scheduler_priority_SMP_Node_initialize, \
89    _Scheduler_default_Node_destroy, \
90    _Scheduler_priority_SMP_Update_priority, \
91    _Scheduler_priority_Priority_compare, \
92    _Scheduler_default_Release_job, \
93    _Scheduler_default_Tick, \
94    _Scheduler_SMP_Start_idle \
95    SCHEDULER_OPERATION_DEFAULT_GET_SET_AFFINITY \
96  }
97
98void _Scheduler_priority_SMP_Initialize( const Scheduler_Control *scheduler );
99
100void _Scheduler_priority_SMP_Node_initialize(
101  const Scheduler_Control *scheduler,
102  Thread_Control *thread
103);
104
105void _Scheduler_priority_SMP_Block(
106  const Scheduler_Control *scheduler,
107  Thread_Control *thread
108);
109
110Thread_Control *_Scheduler_priority_SMP_Unblock(
111  const Scheduler_Control *scheduler,
112  Thread_Control *thread
113);
114
115Thread_Control *_Scheduler_priority_SMP_Change_priority(
116  const Scheduler_Control *scheduler,
117  Thread_Control          *the_thread,
118  Priority_Control         new_priority,
119  bool                     prepend_it
120);
121
122Thread_Control *_Scheduler_priority_SMP_Ask_for_help(
123  const Scheduler_Control *scheduler,
124  Thread_Control          *needs_help,
125  Thread_Control          *offers_help
126);
127
128void _Scheduler_priority_SMP_Update_priority(
129  const Scheduler_Control *scheduler,
130  Thread_Control *thread,
131  Priority_Control new_priority
132);
133
134Thread_Control *_Scheduler_priority_SMP_Yield(
135  const Scheduler_Control *scheduler,
136  Thread_Control *thread
137);
138
139/** @} */
140
141#ifdef __cplusplus
142}
143#endif /* __cplusplus */
144
145#endif /* _RTEMS_SCORE_SCHEDULERPRIORITYSMP_H */
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