1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
|
/***************************************************************************
* Copyright (c) 2024 Microsoft Corporation
*
* This program and the accompanying materials are made available under the
* terms of the MIT License which is available at
* https://opensource.org/licenses/MIT.
*
* SPDX-License-Identifier: MIT
**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** ThreadX Component */
/** */
/** Thread */
/** */
/**************************************************************************/
/**************************************************************************/
#define TX_SOURCE_CODE
/* Include necessary system files. */
#include "tx_api.h"
#include "tx_trace.h"
#include "tx_thread.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_thread_priority_change PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function changes the priority of the specified thread. It */
/* also returns the old priority and handles preemption if the calling */
/* thread is currently executing and the priority change results in a */
/* higher priority thread ready for execution. */
/* */
/* Note: the preemption threshold is automatically changed to the new */
/* priority. */
/* */
/* INPUT */
/* */
/* thread_ptr Pointer to thread to suspend */
/* new_priority New thread priority */
/* old_priority Old thread priority */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _tx_thread_system_resume Resume thread */
/* _tx_thread_system_ni_resume Non-interruptable resume thread */
/* _tx_thread_system_suspend Suspend thread */
/* _tx_thread_system_ni_suspend Non-interruptable suspend thread */
/* _tx_thread_system_preempt_check Check for preemption */
/* */
/* CALLED BY */
/* */
/* Application Code */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 William E. Lamie Initial Version 6.0 */
/* 09-30-2020 William E. Lamie Modified comment(s), and */
/* change thread state from */
/* TX_SUSPENDED to */
/* TX_PRIORITY_CHANGE before */
/* calling */
/* _tx_thread_system_suspend, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
UINT _tx_thread_priority_change(TX_THREAD *thread_ptr, UINT new_priority, UINT *old_priority)
{
TX_INTERRUPT_SAVE_AREA
TX_THREAD *execute_ptr;
TX_THREAD *next_execute_ptr;
UINT original_priority;
/* Lockout interrupts while the thread is being suspended. */
TX_DISABLE
/* Save the previous priority. */
*old_priority = thread_ptr -> tx_thread_user_priority;
/* If trace is enabled, insert this event into the trace buffer. */
TX_TRACE_IN_LINE_INSERT(TX_TRACE_THREAD_PRIORITY_CHANGE, thread_ptr, new_priority, thread_ptr -> tx_thread_priority, thread_ptr -> tx_thread_state, TX_TRACE_THREAD_EVENTS)
/* Log this kernel call. */
TX_EL_THREAD_PRIORITY_CHANGE_INSERT
/* Determine if this thread is currently ready. */
if (thread_ptr -> tx_thread_state != TX_READY)
{
/* Setup the user priority and threshold in the thread's control
block. */
thread_ptr -> tx_thread_user_priority = new_priority;
thread_ptr -> tx_thread_user_preempt_threshold = new_priority;
/* Determine if the actual thread priority should be setup, which is the
case if the new priority is higher than the priority inheritance. */
if (new_priority < thread_ptr -> tx_thread_inherit_priority)
{
/* Change thread priority to the new user's priority. */
thread_ptr -> tx_thread_priority = new_priority;
thread_ptr -> tx_thread_preempt_threshold = new_priority;
}
else
{
/* Change thread priority to the priority inheritance. */
thread_ptr -> tx_thread_priority = thread_ptr -> tx_thread_inherit_priority;
thread_ptr -> tx_thread_preempt_threshold = thread_ptr -> tx_thread_inherit_priority;
}
/* Restore interrupts. */
TX_RESTORE
}
else
{
/* Set the state to priority change. */
thread_ptr -> tx_thread_state = TX_PRIORITY_CHANGE;
/* Pickup the next thread to execute. */
execute_ptr = _tx_thread_execute_ptr;
/* Save the original priority. */
original_priority = thread_ptr -> tx_thread_priority;
#ifdef TX_NOT_INTERRUPTABLE
/* Increment the preempt disable flag. */
_tx_thread_preempt_disable++;
/* Call actual non-interruptable thread suspension routine. */
_tx_thread_system_ni_suspend(thread_ptr, ((ULONG) 0));
/* At this point, the preempt disable flag is still set, so we still have
protection against all preemption. */
/* Setup the new priority for this thread. */
thread_ptr -> tx_thread_user_priority = new_priority;
thread_ptr -> tx_thread_user_preempt_threshold = new_priority;
/* Determine if the actual thread priority should be setup, which is the
case if the new priority is higher than the priority inheritance. */
if (new_priority < thread_ptr -> tx_thread_inherit_priority)
{
/* Change thread priority to the new user's priority. */
thread_ptr -> tx_thread_priority = new_priority;
thread_ptr -> tx_thread_preempt_threshold = new_priority;
}
else
{
/* Change thread priority to the priority inheritance. */
thread_ptr -> tx_thread_priority = thread_ptr -> tx_thread_inherit_priority;
thread_ptr -> tx_thread_preempt_threshold = thread_ptr -> tx_thread_inherit_priority;
}
/* Resume the thread with the new priority. */
_tx_thread_system_ni_resume(thread_ptr);
#else
/* Increment the preempt disable flag by 2 to prevent system suspend from
returning to the system. */
_tx_thread_preempt_disable = _tx_thread_preempt_disable + ((UINT) 3);
/* Set the suspending flag. */
thread_ptr -> tx_thread_suspending = TX_TRUE;
/* Setup the timeout period. */
thread_ptr -> tx_thread_timer.tx_timer_internal_remaining_ticks = ((ULONG) 0);
/* Restore interrupts. */
TX_RESTORE
/* The thread is ready and must first be removed from the list. Call the
system suspend function to accomplish this. */
_tx_thread_system_suspend(thread_ptr);
/* At this point, the preempt disable flag is still set, so we still have
protection against all preemption. */
/* Setup the new priority for this thread. */
thread_ptr -> tx_thread_user_priority = new_priority;
thread_ptr -> tx_thread_user_preempt_threshold = new_priority;
/* Determine if the actual thread priority should be setup, which is the
case if the new priority is higher than the priority inheritance. */
if (new_priority < thread_ptr -> tx_thread_inherit_priority)
{
/* Change thread priority to the new user's priority. */
thread_ptr -> tx_thread_priority = new_priority;
thread_ptr -> tx_thread_preempt_threshold = new_priority;
}
else
{
/* Change thread priority to the priority inheritance. */
thread_ptr -> tx_thread_priority = thread_ptr -> tx_thread_inherit_priority;
thread_ptr -> tx_thread_preempt_threshold = thread_ptr -> tx_thread_inherit_priority;
}
/* Resume the thread with the new priority. */
_tx_thread_system_resume(thread_ptr);
/* Disable interrupts. */
TX_DISABLE
#endif
/* Decrement the preempt disable flag. */
_tx_thread_preempt_disable--;
/* Pickup the next thread to execute. */
next_execute_ptr = _tx_thread_execute_ptr;
/* Determine if this thread is not the next thread to execute. */
if (thread_ptr != next_execute_ptr)
{
/* Make sure the thread is still ready. */
if (thread_ptr -> tx_thread_state == TX_READY)
{
/* Now check and see if this thread has an equal or higher priority. */
if (thread_ptr -> tx_thread_priority <= next_execute_ptr -> tx_thread_priority)
{
/* Now determine if this thread was the previously executing thread. */
if (thread_ptr == execute_ptr)
{
/* Yes, this thread was previously executing before we temporarily suspended and resumed
it in order to change the priority. A lower or same priority thread cannot be the next thread
to execute in this case since this thread really didn't suspend. Simply reset the execute
pointer to this thread. */
_tx_thread_execute_ptr = thread_ptr;
/* Determine if we moved to a lower priority. If so, move the thread to the front of its priority list. */
if (original_priority < new_priority)
{
/* Ensure that this thread is placed at the front of the priority list. */
_tx_thread_priority_list[thread_ptr -> tx_thread_priority] = thread_ptr;
}
}
}
}
}
/* Restore interrupts. */
TX_RESTORE
/* Check for preemption. */
_tx_thread_system_preempt_check();
}
/* Return success if we get here! */
return(TX_SUCCESS);
}
|
