root / prex-0.9.0 / usr / sample / mutex / mutex.c @ 03e9c04a
History | View | Annotate | Download (5.59 KB)
1 |
/*
|
---|---|
2 |
* Copyright (c) 2005, Kohsuke Ohtani
|
3 |
* All rights reserved.
|
4 |
*
|
5 |
* Redistribution and use in source and binary forms, with or without
|
6 |
* modification, are permitted provided that the following conditions
|
7 |
* are met:
|
8 |
* 1. Redistributions of source code must retain the above copyright
|
9 |
* notice, this list of conditions and the following disclaimer.
|
10 |
* 2. Redistributions in binary form must reproduce the above copyright
|
11 |
* notice, this list of conditions and the following disclaimer in the
|
12 |
* documentation and/or other materials provided with the distribution.
|
13 |
* 3. Neither the name of the author nor the names of any co-contributors
|
14 |
* may be used to endorse or promote products derived from this software
|
15 |
* without specific prior written permission.
|
16 |
*
|
17 |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
18 |
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
19 |
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
20 |
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
21 |
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
22 |
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
23 |
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
24 |
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
25 |
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
26 |
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
27 |
* SUCH DAMAGE.
|
28 |
*/
|
29 |
|
30 |
/*
|
31 |
* mutex.c - sample program for mutex with priority inheritance.
|
32 |
*/
|
33 |
|
34 |
/*
|
35 |
* Senario:
|
36 |
* This sample shows how the mutex priority is changed when three
|
37 |
* different threads lock two mutexes at same time.
|
38 |
*
|
39 |
* The priority of each thread are as follows.
|
40 |
* Thread1 - priority 100 (highest)
|
41 |
* Thread2 - priority 101
|
42 |
* Thread3 - priority 102
|
43 |
*
|
44 |
* Thread priority and state are changed as follows.
|
45 |
*
|
46 |
* Action Thread 1 Thread 2 Thread 3 Mutex A Mutex B
|
47 |
* ------------------------ -------- -------- -------- ------- -------
|
48 |
* 1) Thread 3 locks mutex A susp/100 susp/101 run /102 owner=3
|
49 |
* 2) Thread 2 locks mutex B susp/100 run /101 run /102 owner=3 owner=2
|
50 |
* 3) Thread 2 locks mutex A susp/100 wait/101 run /101* owner=3 owner=2
|
51 |
* 4) Thread 1 locks mutex B wait/100 wait/100* run /100* owner=3 owner=2
|
52 |
* 5) Thread 3 unlocks mutex A wait/100 run /100 run /102* owner=2* owner=2
|
53 |
* 6) Thread 2 unlocks mutex B run /100* run /100 run /102 owner=2 owner=1*
|
54 |
* 7) Thread 2 unlocks mutex A run /100 run /100 run /102 owner=1
|
55 |
* 8) Thread 1 unlocks mutex B wait/100 run /101 run /102
|
56 |
*
|
57 |
*/
|
58 |
|
59 |
#include <sys/prex.h> |
60 |
#include <stdio.h> |
61 |
|
62 |
static char stack[3][1024]; |
63 |
static thread_t th_1, th_2, th_3;
|
64 |
static mutex_t mtx_A, mtx_B;
|
65 |
|
66 |
static void |
67 |
dump_pri(void)
|
68 |
{ |
69 |
int pri;
|
70 |
|
71 |
if (thread_getpri(th_1, &pri) == 0) |
72 |
printf("th_1: pri=%d\n", pri);
|
73 |
|
74 |
if (thread_getpri(th_2, &pri) == 0) |
75 |
printf("th_2: pri=%d\n", pri);
|
76 |
|
77 |
if (thread_getpri(th_3, &pri) == 0) |
78 |
printf("th_3: pri=%d\n", pri);
|
79 |
} |
80 |
|
81 |
thread_t |
82 |
thread_run(void (*start)(void), void *stack) |
83 |
{ |
84 |
thread_t t; |
85 |
|
86 |
if (thread_create(task_self(), &t) != 0) |
87 |
panic("thread_create is failed");
|
88 |
|
89 |
if (thread_load(t, start, stack) != 0) |
90 |
panic("thread_load is failed");
|
91 |
|
92 |
return t;
|
93 |
} |
94 |
|
95 |
/*
|
96 |
* Thread 1 - Priority = 100
|
97 |
*/
|
98 |
static void |
99 |
thread_1(void)
|
100 |
{ |
101 |
printf("thread_1: starting\n");
|
102 |
|
103 |
/*
|
104 |
* 4) Lock mutex B
|
105 |
*
|
106 |
* Priority inheritance:
|
107 |
* Thread 2... Pri 101 -> 100
|
108 |
* Thread 3... Pri 101 -> 100
|
109 |
*/
|
110 |
printf("thread_1: 4) lock B\n");
|
111 |
mutex_lock(&mtx_B); |
112 |
|
113 |
printf("thread_1: running\n");
|
114 |
dump_pri(); |
115 |
|
116 |
/*
|
117 |
* 8) Unlock mutex B
|
118 |
*/
|
119 |
printf("thread_1: 7) unlock B\n");
|
120 |
mutex_unlock(&mtx_B); |
121 |
|
122 |
dump_pri(); |
123 |
printf("thread_1: exit\n");
|
124 |
thread_terminate(th_1); |
125 |
} |
126 |
|
127 |
/*
|
128 |
* Thread 2 - Priority = 101
|
129 |
*/
|
130 |
static void |
131 |
thread_2(void)
|
132 |
{ |
133 |
printf("thread_2: starting\n");
|
134 |
|
135 |
/*
|
136 |
* 2) Lock mutex B
|
137 |
*/
|
138 |
printf("thread_2: 2) lock B\n");
|
139 |
mutex_lock(&mtx_B); |
140 |
dump_pri(); |
141 |
|
142 |
/*
|
143 |
* 3) Lock mutex A (Switch to thread 3)
|
144 |
*
|
145 |
* Priority inheritance:
|
146 |
* Thread 3... Pri 102 -> 101
|
147 |
*/
|
148 |
printf("thread_2: 3) lock A\n");
|
149 |
mutex_lock(&mtx_A); |
150 |
|
151 |
printf("thread_2: running\n");
|
152 |
dump_pri(); |
153 |
|
154 |
/*
|
155 |
* 6) Unlock mutex B
|
156 |
*/
|
157 |
printf("thread_2: 6) unlock B\n");
|
158 |
mutex_unlock(&mtx_B); |
159 |
|
160 |
dump_pri(); |
161 |
|
162 |
/*
|
163 |
* 7) Unlock mutex A
|
164 |
*/
|
165 |
printf("thread_2: 8) unlock A\n");
|
166 |
mutex_unlock(&mtx_A); |
167 |
|
168 |
printf("thread_2: exit\n");
|
169 |
thread_terminate(th_2); |
170 |
} |
171 |
|
172 |
|
173 |
/*
|
174 |
* Thread 3 - Priority = 102
|
175 |
*/
|
176 |
static void |
177 |
thread_3(void)
|
178 |
{ |
179 |
printf("thread_3: start\n");
|
180 |
|
181 |
/*
|
182 |
* 1) Lock mutex A
|
183 |
*/
|
184 |
printf("thread_3: 1) lock A\n");
|
185 |
mutex_lock(&mtx_A); |
186 |
dump_pri(); |
187 |
|
188 |
/*
|
189 |
* Start thread 2
|
190 |
*/
|
191 |
thread_resume(th_2); |
192 |
|
193 |
/*
|
194 |
* Check priority
|
195 |
*/
|
196 |
printf("thread_3: running-1\n");
|
197 |
dump_pri(); |
198 |
|
199 |
/*
|
200 |
* Start thread 1
|
201 |
*/
|
202 |
thread_resume(th_1); |
203 |
printf("thread_3: running-2\n");
|
204 |
dump_pri(); |
205 |
|
206 |
/*
|
207 |
* 5) Unlock mutex A
|
208 |
*/
|
209 |
printf("thread_3: 5) unlock A\n");
|
210 |
mutex_unlock(&mtx_A); |
211 |
|
212 |
dump_pri(); |
213 |
printf("thread_3: exit\n");
|
214 |
thread_terminate(th_3); |
215 |
} |
216 |
|
217 |
int
|
218 |
main(int argc, char *argv[]) |
219 |
{ |
220 |
printf("Mutex sample program\n");
|
221 |
|
222 |
/*
|
223 |
* Boost priority of this thread
|
224 |
*/
|
225 |
thread_setpri(thread_self(), 90);
|
226 |
|
227 |
/*
|
228 |
* Initialize mutexes.
|
229 |
*/
|
230 |
mutex_init(&mtx_A); |
231 |
mutex_init(&mtx_B); |
232 |
|
233 |
/*
|
234 |
* Create new threads
|
235 |
*/
|
236 |
th_1 = thread_run(thread_1, stack[0]+1024); |
237 |
thread_setpri(th_1, 100);
|
238 |
|
239 |
th_2 = thread_run(thread_2, stack[1]+1024); |
240 |
thread_setpri(th_2, 101);
|
241 |
|
242 |
th_3 = thread_run(thread_3, stack[2]+1024); |
243 |
thread_setpri(th_3, 102);
|
244 |
|
245 |
dump_pri(); |
246 |
|
247 |
/*
|
248 |
* Start lowest priority thread
|
249 |
*/
|
250 |
thread_resume(th_3); |
251 |
|
252 |
/*
|
253 |
* Wait...
|
254 |
*/
|
255 |
thread_suspend(thread_self()); |
256 |
|
257 |
return 0; |
258 |
} |