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20#include <errno.h>
21#include <limits.h>
22#include <pthread.h>
23#include <stdio.h>
24#include <stdlib.h>
25#include <signal.h>
26#include <string.h>
27#include "atomic.h"
28#include "futextest.h"
29#include "logging.h"
30
31#define TEST_NAME "futex-requeue-pi"
32#define MAX_WAKE_ITERS 1000
33#define THREAD_MAX 10
34#define SIGNAL_PERIOD_US 100
35
36atomic_t waiters_blocked = ATOMIC_INITIALIZER;
37atomic_t waiters_woken = ATOMIC_INITIALIZER;
38
39futex_t f1 = FUTEX_INITIALIZER;
40futex_t f2 = FUTEX_INITIALIZER;
41futex_t wake_complete = FUTEX_INITIALIZER;
42
43
44static long timeout_ns;
45static int broadcast;
46static int owner;
47static int locked;
48
49struct thread_arg {
50 long id;
51 struct timespec *timeout;
52 int lock;
53 int ret;
54};
55#define THREAD_ARG_INITIALIZER { 0, NULL, 0, 0 }
56
57void usage(char *prog)
58{
59 printf("Usage: %s\n", prog);
60 printf(" -b Broadcast wakeup (all waiters)\n");
61 printf(" -c Use color\n");
62 printf(" -h Display this help message\n");
63 printf(" -l Lock the pi futex across requeue\n");
64 printf(" -o Use a third party pi futex owner during requeue (cancels -l)\n");
65 printf(" -t N Timeout in nanoseconds (default: 0)\n");
66 printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
67 VQUIET, VCRITICAL, VINFO);
68}
69
70int create_rt_thread(pthread_t *pth, void*(*func)(void *), void *arg,
71 int policy, int prio)
72{
73 int ret;
74 struct sched_param schedp;
75 pthread_attr_t attr;
76
77 pthread_attr_init(&attr);
78 memset(&schedp, 0, sizeof(schedp));
79
80 ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
81 if (ret) {
82 error("pthread_attr_setinheritsched\n", ret);
83 return -1;
84 }
85
86 ret = pthread_attr_setschedpolicy(&attr, policy);
87 if (ret) {
88 error("pthread_attr_setschedpolicy\n", ret);
89 return -1;
90 }
91
92 schedp.sched_priority = prio;
93 ret = pthread_attr_setschedparam(&attr, &schedp);
94 if (ret) {
95 error("pthread_attr_setschedparam\n", ret);
96 return -1;
97 }
98
99 ret = pthread_create(pth, &attr, func, arg);
100 if (ret) {
101 error("pthread_create\n", ret);
102 return -1;
103 }
104 return 0;
105}
106
107
108void *waiterfn(void *arg)
109{
110 struct thread_arg *args = (struct thread_arg *)arg;
111 futex_t old_val;
112
113 info("Waiter %ld: running\n", args->id);
114
115
116
117 usleep(1000 * (long)args->id);
118
119 old_val = f1;
120 atomic_inc(&waiters_blocked);
121 info("Calling futex_wait_requeue_pi: %p (%u) -> %p\n",
122 &f1, f1, &f2);
123 args->ret = futex_wait_requeue_pi(&f1, old_val, &f2, args->timeout,
124 FUTEX_PRIVATE_FLAG);
125
126 info("waiter %ld woke with %d %s\n", args->id, args->ret,
127 args->ret < 0 ? strerror(errno) : "");
128 atomic_inc(&waiters_woken);
129 if (args->ret < 0) {
130 if (args->timeout && errno == ETIMEDOUT)
131 args->ret = 0;
132 else {
133 args->ret = RET_ERROR;
134 error("futex_wait_requeue_pi\n", errno);
135 }
136 futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
137 }
138 futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
139
140 info("Waiter %ld: exiting with %d\n", args->id, args->ret);
141 pthread_exit((void *)&args->ret);
142}
143
144void *broadcast_wakerfn(void *arg)
145{
146 struct thread_arg *args = (struct thread_arg *)arg;
147 int nr_requeue = INT_MAX;
148 int task_count = 0;
149 futex_t old_val;
150 int nr_wake = 1;
151 int i = 0;
152
153 info("Waker: waiting for waiters to block\n");
154 while (waiters_blocked.val < THREAD_MAX)
155 usleep(1000);
156 usleep(1000);
157
158 info("Waker: Calling broadcast\n");
159 if (args->lock) {
160 info("Calling FUTEX_LOCK_PI on mutex=%x @ %p\n", f2, &f2);
161 futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
162 }
163 continue_requeue:
164 old_val = f1;
165 args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2, nr_wake, nr_requeue,
166 FUTEX_PRIVATE_FLAG);
167 if (args->ret < 0) {
168 args->ret = RET_ERROR;
169 error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
170 } else if (++i < MAX_WAKE_ITERS) {
171 task_count += args->ret;
172 if (task_count < THREAD_MAX - waiters_woken.val)
173 goto continue_requeue;
174 } else {
175 error("max broadcast iterations (%d) reached with %d/%d tasks woken or requeued\n",
176 0, MAX_WAKE_ITERS, task_count, THREAD_MAX);
177 args->ret = RET_ERROR;
178 }
179
180 futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
181
182 if (args->lock)
183 futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
184
185 if (args->ret > 0)
186 args->ret = task_count;
187
188 info("Waker: exiting with %d\n", args->ret);
189 pthread_exit((void *)&args->ret);
190}
191
192void *signal_wakerfn(void *arg)
193{
194 struct thread_arg *args = (struct thread_arg *)arg;
195 unsigned int old_val;
196 int nr_requeue = 0;
197 int task_count = 0;
198 int nr_wake = 1;
199 int i = 0;
200
201 info("Waker: waiting for waiters to block\n");
202 while (waiters_blocked.val < THREAD_MAX)
203 usleep(1000);
204 usleep(1000);
205
206 while (task_count < THREAD_MAX && waiters_woken.val < THREAD_MAX) {
207 info("task_count: %d, waiters_woken: %d\n",
208 task_count, waiters_woken.val);
209 if (args->lock) {
210 info("Calling FUTEX_LOCK_PI on mutex=%x @ %p\n",
211 f2, &f2);
212 futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
213 }
214 info("Waker: Calling signal\n");
215
216 old_val = f1;
217 args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2,
218 nr_wake, nr_requeue,
219 FUTEX_PRIVATE_FLAG);
220 if (args->ret < 0)
221 args->ret = -errno;
222 info("futex: %x\n", f2);
223 if (args->lock) {
224 info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n",
225 f2, &f2);
226 futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
227 }
228 info("futex: %x\n", f2);
229 if (args->ret < 0) {
230 error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
231 args->ret = RET_ERROR;
232 break;
233 }
234
235 task_count += args->ret;
236 usleep(SIGNAL_PERIOD_US);
237 i++;
238
239 if (i > MAX_WAKE_ITERS + THREAD_MAX) {
240 error("max signaling iterations (%d) reached, giving up on pending waiters.\n",
241 0, MAX_WAKE_ITERS + THREAD_MAX);
242 args->ret = RET_ERROR;
243 break;
244 }
245 }
246
247 futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
248
249 if (args->ret >= 0)
250 args->ret = task_count;
251
252 info("Waker: exiting with %d\n", args->ret);
253 info("Waker: waiters_woken: %d\n", waiters_woken.val);
254 pthread_exit((void *)&args->ret);
255}
256
257void *third_party_blocker(void *arg)
258{
259 struct thread_arg *args = (struct thread_arg *)arg;
260 int ret2 = 0;
261
262 args->ret = futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
263 if (args->ret)
264 goto out;
265 args->ret = futex_wait(&wake_complete, wake_complete, NULL,
266 FUTEX_PRIVATE_FLAG);
267 ret2 = futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
268
269 out:
270 if (args->ret || ret2) {
271 error("third_party_blocker() futex error", 0);
272 args->ret = RET_ERROR;
273 }
274
275 pthread_exit((void *)&args->ret);
276}
277
278int unit_test(int broadcast, long lock, int third_party_owner, long timeout_ns)
279{
280 void *(*wakerfn)(void *) = signal_wakerfn;
281 struct thread_arg blocker_arg = THREAD_ARG_INITIALIZER;
282 struct thread_arg waker_arg = THREAD_ARG_INITIALIZER;
283 pthread_t waiter[THREAD_MAX], waker, blocker;
284 struct timespec ts, *tsp = NULL;
285 struct thread_arg args[THREAD_MAX];
286 int *waiter_ret;
287 int i, ret = RET_PASS;
288
289 if (timeout_ns) {
290 time_t secs;
291
292 info("timeout_ns = %ld\n", timeout_ns);
293 ret = clock_gettime(CLOCK_MONOTONIC, &ts);
294 secs = (ts.tv_nsec + timeout_ns) / 1000000000;
295 ts.tv_nsec = ((int64_t)ts.tv_nsec + timeout_ns) % 1000000000;
296 ts.tv_sec += secs;
297 info("ts.tv_sec = %ld\n", ts.tv_sec);
298 info("ts.tv_nsec = %ld\n", ts.tv_nsec);
299 tsp = &ts;
300 }
301
302 if (broadcast)
303 wakerfn = broadcast_wakerfn;
304
305 if (third_party_owner) {
306 if (create_rt_thread(&blocker, third_party_blocker,
307 (void *)&blocker_arg, SCHED_FIFO, 1)) {
308 error("Creating third party blocker thread failed\n",
309 errno);
310 ret = RET_ERROR;
311 goto out;
312 }
313 }
314
315 atomic_set(&waiters_woken, 0);
316 for (i = 0; i < THREAD_MAX; i++) {
317 args[i].id = i;
318 args[i].timeout = tsp;
319 info("Starting thread %d\n", i);
320 if (create_rt_thread(&waiter[i], waiterfn, (void *)&args[i],
321 SCHED_FIFO, 1)) {
322 error("Creating waiting thread failed\n", errno);
323 ret = RET_ERROR;
324 goto out;
325 }
326 }
327 waker_arg.lock = lock;
328 if (create_rt_thread(&waker, wakerfn, (void *)&waker_arg,
329 SCHED_FIFO, 1)) {
330 error("Creating waker thread failed\n", errno);
331 ret = RET_ERROR;
332 goto out;
333 }
334
335
336
337 waiter_ret = &args[0].ret;
338 for (i = 0; i < THREAD_MAX; i++)
339 pthread_join(waiter[i],
340 *waiter_ret ? NULL : (void **)&waiter_ret);
341
342 if (third_party_owner)
343 pthread_join(blocker, NULL);
344 pthread_join(waker, NULL);
345
346out:
347 if (!ret) {
348 if (*waiter_ret)
349 ret = *waiter_ret;
350 else if (waker_arg.ret < 0)
351 ret = waker_arg.ret;
352 else if (blocker_arg.ret)
353 ret = blocker_arg.ret;
354 }
355
356 return ret;
357}
358
359int main(int argc, char *argv[])
360{
361 int c, ret;
362
363 while ((c = getopt(argc, argv, "bchlot:v:")) != -1) {
364 switch (c) {
365 case 'b':
366 broadcast = 1;
367 break;
368 case 'c':
369 log_color(1);
370 break;
371 case 'h':
372 usage(basename(argv[0]));
373 exit(0);
374 case 'l':
375 locked = 1;
376 break;
377 case 'o':
378 owner = 1;
379 locked = 0;
380 break;
381 case 't':
382 timeout_ns = atoi(optarg);
383 break;
384 case 'v':
385 log_verbosity(atoi(optarg));
386 break;
387 default:
388 usage(basename(argv[0]));
389 exit(1);
390 }
391 }
392
393 ksft_print_header();
394 ksft_set_plan(1);
395 ksft_print_msg("%s: Test requeue functionality\n", basename(argv[0]));
396 ksft_print_msg(
397 "\tArguments: broadcast=%d locked=%d owner=%d timeout=%ldns\n",
398 broadcast, locked, owner, timeout_ns);
399
400
401
402
403
404
405 ret = unit_test(broadcast, locked, owner, timeout_ns);
406
407 print_result(TEST_NAME, ret);
408 return ret;
409}
410
