xref: /linux/tools/testing/selftests/futex/functional/futex_requeue_pi.c (revision 6d9b262afe0ec1d6e0ef99321ca9d6b921310471)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /******************************************************************************
3  *
4  *   Copyright © International Business Machines  Corp., 2006-2008
5  *
6  * DESCRIPTION
7  *      This test excercises the futex syscall op codes needed for requeuing
8  *      priority inheritance aware POSIX condition variables and mutexes.
9  *
10  * AUTHORS
11  *      Sripathi Kodi <sripathik@in.ibm.com>
12  *      Darren Hart <dvhart@linux.intel.com>
13  *
14  * HISTORY
15  *      2008-Jan-13: Initial version by Sripathi Kodi <sripathik@in.ibm.com>
16  *      2009-Nov-6: futex test adaptation by Darren Hart <dvhart@linux.intel.com>
17  *
18  *****************************************************************************/
19 
20 #define _GNU_SOURCE
21 
22 #include <errno.h>
23 #include <limits.h>
24 #include <pthread.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <signal.h>
28 #include <string.h>
29 #include "atomic.h"
30 #include "futextest.h"
31 #include "logging.h"
32 
33 #define TEST_NAME "futex-requeue-pi"
34 #define MAX_WAKE_ITERS 1000
35 #define THREAD_MAX 10
36 #define SIGNAL_PERIOD_US 100
37 
38 atomic_t waiters_blocked = ATOMIC_INITIALIZER;
39 atomic_t waiters_woken = ATOMIC_INITIALIZER;
40 
41 futex_t f1 = FUTEX_INITIALIZER;
42 futex_t f2 = FUTEX_INITIALIZER;
43 futex_t wake_complete = FUTEX_INITIALIZER;
44 
45 /* Test option defaults */
46 static long timeout_ns;
47 static int broadcast;
48 static int owner;
49 static int locked;
50 
51 struct thread_arg {
52 	long id;
53 	struct timespec *timeout;
54 	int lock;
55 	int ret;
56 };
57 #define THREAD_ARG_INITIALIZER { 0, NULL, 0, 0 }
58 
59 void usage(char *prog)
60 {
61 	printf("Usage: %s\n", prog);
62 	printf("  -b	Broadcast wakeup (all waiters)\n");
63 	printf("  -c	Use color\n");
64 	printf("  -h	Display this help message\n");
65 	printf("  -l	Lock the pi futex across requeue\n");
66 	printf("  -o	Use a third party pi futex owner during requeue (cancels -l)\n");
67 	printf("  -t N	Timeout in nanoseconds (default: 0)\n");
68 	printf("  -v L	Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
69 	       VQUIET, VCRITICAL, VINFO);
70 }
71 
72 int create_rt_thread(pthread_t *pth, void*(*func)(void *), void *arg,
73 		     int policy, int prio)
74 {
75 	int ret;
76 	struct sched_param schedp;
77 	pthread_attr_t attr;
78 
79 	pthread_attr_init(&attr);
80 	memset(&schedp, 0, sizeof(schedp));
81 
82 	ret = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
83 	if (ret) {
84 		error("pthread_attr_setinheritsched\n", ret);
85 		return -1;
86 	}
87 
88 	ret = pthread_attr_setschedpolicy(&attr, policy);
89 	if (ret) {
90 		error("pthread_attr_setschedpolicy\n", ret);
91 		return -1;
92 	}
93 
94 	schedp.sched_priority = prio;
95 	ret = pthread_attr_setschedparam(&attr, &schedp);
96 	if (ret) {
97 		error("pthread_attr_setschedparam\n", ret);
98 		return -1;
99 	}
100 
101 	ret = pthread_create(pth, &attr, func, arg);
102 	if (ret) {
103 		error("pthread_create\n", ret);
104 		return -1;
105 	}
106 	return 0;
107 }
108 
109 
110 void *waiterfn(void *arg)
111 {
112 	struct thread_arg *args = (struct thread_arg *)arg;
113 	futex_t old_val;
114 
115 	info("Waiter %ld: running\n", args->id);
116 	/* Each thread sleeps for a different amount of time
117 	 * This is to avoid races, because we don't lock the
118 	 * external mutex here */
119 	usleep(1000 * (long)args->id);
120 
121 	old_val = f1;
122 	atomic_inc(&waiters_blocked);
123 	info("Calling futex_wait_requeue_pi: %p (%u) -> %p\n",
124 	     &f1, f1, &f2);
125 	args->ret = futex_wait_requeue_pi(&f1, old_val, &f2, args->timeout,
126 					  FUTEX_PRIVATE_FLAG);
127 
128 	info("waiter %ld woke with %d %s\n", args->id, args->ret,
129 	     args->ret < 0 ? strerror(errno) : "");
130 	atomic_inc(&waiters_woken);
131 	if (args->ret < 0) {
132 		if (args->timeout && errno == ETIMEDOUT)
133 			args->ret = 0;
134 		else {
135 			args->ret = RET_ERROR;
136 			error("futex_wait_requeue_pi\n", errno);
137 		}
138 		futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
139 	}
140 	futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
141 
142 	info("Waiter %ld: exiting with %d\n", args->id, args->ret);
143 	pthread_exit((void *)&args->ret);
144 }
145 
146 void *broadcast_wakerfn(void *arg)
147 {
148 	struct thread_arg *args = (struct thread_arg *)arg;
149 	int nr_requeue = INT_MAX;
150 	int task_count = 0;
151 	futex_t old_val;
152 	int nr_wake = 1;
153 	int i = 0;
154 
155 	info("Waker: waiting for waiters to block\n");
156 	while (waiters_blocked.val < THREAD_MAX)
157 		usleep(1000);
158 	usleep(1000);
159 
160 	info("Waker: Calling broadcast\n");
161 	if (args->lock) {
162 		info("Calling FUTEX_LOCK_PI on mutex=%x @ %p\n", f2, &f2);
163 		futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
164 	}
165  continue_requeue:
166 	old_val = f1;
167 	args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2, nr_wake, nr_requeue,
168 				   FUTEX_PRIVATE_FLAG);
169 	if (args->ret < 0) {
170 		args->ret = RET_ERROR;
171 		error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
172 	} else if (++i < MAX_WAKE_ITERS) {
173 		task_count += args->ret;
174 		if (task_count < THREAD_MAX - waiters_woken.val)
175 			goto continue_requeue;
176 	} else {
177 		error("max broadcast iterations (%d) reached with %d/%d tasks woken or requeued\n",
178 		       0, MAX_WAKE_ITERS, task_count, THREAD_MAX);
179 		args->ret = RET_ERROR;
180 	}
181 
182 	futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
183 
184 	if (args->lock)
185 		futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
186 
187 	if (args->ret > 0)
188 		args->ret = task_count;
189 
190 	info("Waker: exiting with %d\n", args->ret);
191 	pthread_exit((void *)&args->ret);
192 }
193 
194 void *signal_wakerfn(void *arg)
195 {
196 	struct thread_arg *args = (struct thread_arg *)arg;
197 	unsigned int old_val;
198 	int nr_requeue = 0;
199 	int task_count = 0;
200 	int nr_wake = 1;
201 	int i = 0;
202 
203 	info("Waker: waiting for waiters to block\n");
204 	while (waiters_blocked.val < THREAD_MAX)
205 		usleep(1000);
206 	usleep(1000);
207 
208 	while (task_count < THREAD_MAX && waiters_woken.val < THREAD_MAX) {
209 		info("task_count: %d, waiters_woken: %d\n",
210 		     task_count, waiters_woken.val);
211 		if (args->lock) {
212 			info("Calling FUTEX_LOCK_PI on mutex=%x @ %p\n",
213 			     f2, &f2);
214 			futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
215 		}
216 		info("Waker: Calling signal\n");
217 		/* cond_signal */
218 		old_val = f1;
219 		args->ret = futex_cmp_requeue_pi(&f1, old_val, &f2,
220 						 nr_wake, nr_requeue,
221 						 FUTEX_PRIVATE_FLAG);
222 		if (args->ret < 0)
223 			args->ret = -errno;
224 		info("futex: %x\n", f2);
225 		if (args->lock) {
226 			info("Calling FUTEX_UNLOCK_PI on mutex=%x @ %p\n",
227 			     f2, &f2);
228 			futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
229 		}
230 		info("futex: %x\n", f2);
231 		if (args->ret < 0) {
232 			error("FUTEX_CMP_REQUEUE_PI failed\n", errno);
233 			args->ret = RET_ERROR;
234 			break;
235 		}
236 
237 		task_count += args->ret;
238 		usleep(SIGNAL_PERIOD_US);
239 		i++;
240 		/* we have to loop at least THREAD_MAX times */
241 		if (i > MAX_WAKE_ITERS + THREAD_MAX) {
242 			error("max signaling iterations (%d) reached, giving up on pending waiters.\n",
243 			      0, MAX_WAKE_ITERS + THREAD_MAX);
244 			args->ret = RET_ERROR;
245 			break;
246 		}
247 	}
248 
249 	futex_wake(&wake_complete, 1, FUTEX_PRIVATE_FLAG);
250 
251 	if (args->ret >= 0)
252 		args->ret = task_count;
253 
254 	info("Waker: exiting with %d\n", args->ret);
255 	info("Waker: waiters_woken: %d\n", waiters_woken.val);
256 	pthread_exit((void *)&args->ret);
257 }
258 
259 void *third_party_blocker(void *arg)
260 {
261 	struct thread_arg *args = (struct thread_arg *)arg;
262 	int ret2 = 0;
263 
264 	args->ret = futex_lock_pi(&f2, NULL, 0, FUTEX_PRIVATE_FLAG);
265 	if (args->ret)
266 		goto out;
267 	args->ret = futex_wait(&wake_complete, wake_complete, NULL,
268 			       FUTEX_PRIVATE_FLAG);
269 	ret2 = futex_unlock_pi(&f2, FUTEX_PRIVATE_FLAG);
270 
271  out:
272 	if (args->ret || ret2) {
273 		error("third_party_blocker() futex error", 0);
274 		args->ret = RET_ERROR;
275 	}
276 
277 	pthread_exit((void *)&args->ret);
278 }
279 
280 int unit_test(int broadcast, long lock, int third_party_owner, long timeout_ns)
281 {
282 	void *(*wakerfn)(void *) = signal_wakerfn;
283 	struct thread_arg blocker_arg = THREAD_ARG_INITIALIZER;
284 	struct thread_arg waker_arg = THREAD_ARG_INITIALIZER;
285 	pthread_t waiter[THREAD_MAX], waker, blocker;
286 	struct timespec ts, *tsp = NULL;
287 	struct thread_arg args[THREAD_MAX];
288 	int *waiter_ret;
289 	int i, ret = RET_PASS;
290 
291 	if (timeout_ns) {
292 		time_t secs;
293 
294 		info("timeout_ns = %ld\n", timeout_ns);
295 		ret = clock_gettime(CLOCK_MONOTONIC, &ts);
296 		secs = (ts.tv_nsec + timeout_ns) / 1000000000;
297 		ts.tv_nsec = ((int64_t)ts.tv_nsec + timeout_ns) % 1000000000;
298 		ts.tv_sec += secs;
299 		info("ts.tv_sec  = %ld\n", ts.tv_sec);
300 		info("ts.tv_nsec = %ld\n", ts.tv_nsec);
301 		tsp = &ts;
302 	}
303 
304 	if (broadcast)
305 		wakerfn = broadcast_wakerfn;
306 
307 	if (third_party_owner) {
308 		if (create_rt_thread(&blocker, third_party_blocker,
309 				     (void *)&blocker_arg, SCHED_FIFO, 1)) {
310 			error("Creating third party blocker thread failed\n",
311 			      errno);
312 			ret = RET_ERROR;
313 			goto out;
314 		}
315 	}
316 
317 	atomic_set(&waiters_woken, 0);
318 	for (i = 0; i < THREAD_MAX; i++) {
319 		args[i].id = i;
320 		args[i].timeout = tsp;
321 		info("Starting thread %d\n", i);
322 		if (create_rt_thread(&waiter[i], waiterfn, (void *)&args[i],
323 				     SCHED_FIFO, 1)) {
324 			error("Creating waiting thread failed\n", errno);
325 			ret = RET_ERROR;
326 			goto out;
327 		}
328 	}
329 	waker_arg.lock = lock;
330 	if (create_rt_thread(&waker, wakerfn, (void *)&waker_arg,
331 			     SCHED_FIFO, 1)) {
332 		error("Creating waker thread failed\n", errno);
333 		ret = RET_ERROR;
334 		goto out;
335 	}
336 
337 	/* Wait for threads to finish */
338 	/* Store the first error or failure encountered in waiter_ret */
339 	waiter_ret = &args[0].ret;
340 	for (i = 0; i < THREAD_MAX; i++)
341 		pthread_join(waiter[i],
342 			     *waiter_ret ? NULL : (void **)&waiter_ret);
343 
344 	if (third_party_owner)
345 		pthread_join(blocker, NULL);
346 	pthread_join(waker, NULL);
347 
348 out:
349 	if (!ret) {
350 		if (*waiter_ret)
351 			ret = *waiter_ret;
352 		else if (waker_arg.ret < 0)
353 			ret = waker_arg.ret;
354 		else if (blocker_arg.ret)
355 			ret = blocker_arg.ret;
356 	}
357 
358 	return ret;
359 }
360 
361 int main(int argc, char *argv[])
362 {
363 	const char *test_name;
364 	int c, ret;
365 
366 	while ((c = getopt(argc, argv, "bchlot:v:")) != -1) {
367 		switch (c) {
368 		case 'b':
369 			broadcast = 1;
370 			break;
371 		case 'c':
372 			log_color(1);
373 			break;
374 		case 'h':
375 			usage(basename(argv[0]));
376 			exit(0);
377 		case 'l':
378 			locked = 1;
379 			break;
380 		case 'o':
381 			owner = 1;
382 			locked = 0;
383 			break;
384 		case 't':
385 			timeout_ns = atoi(optarg);
386 			break;
387 		case 'v':
388 			log_verbosity(atoi(optarg));
389 			break;
390 		default:
391 			usage(basename(argv[0]));
392 			exit(1);
393 		}
394 	}
395 
396 	ksft_print_header();
397 	ksft_set_plan(1);
398 	ksft_print_msg("%s: Test requeue functionality\n", basename(argv[0]));
399 	ksft_print_msg(
400 		"\tArguments: broadcast=%d locked=%d owner=%d timeout=%ldns\n",
401 		broadcast, locked, owner, timeout_ns);
402 
403 	ret = asprintf(&test_name,
404 		       "%s broadcast=%d locked=%d owner=%d timeout=%ldns",
405 		       TEST_NAME, broadcast, locked, owner, timeout_ns);
406 	if (ret < 0) {
407 		ksft_print_msg("Failed to generate test name\n");
408 		test_name = TEST_NAME;
409 	}
410 
411 	/*
412 	 * FIXME: unit_test is obsolete now that we parse options and the
413 	 * various style of runs are done by run.sh - simplify the code and move
414 	 * unit_test into main()
415 	 */
416 	ret = unit_test(broadcast, locked, owner, timeout_ns);
417 
418 	print_result(test_name, ret);
419 	return ret;
420 }
421