tools/testing/selftests/futex/functional/futex_requeue_pi.c

   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 <[email protected]>
  12  *      Darren Hart <[email protected]>
  13  *
  14  * HISTORY
  15  *      2008-Jan-13: Initial version by Sripathi Kodi <[email protected]>
  16  *      2009-Nov-6: futex test adaptation by Darren Hart <[email protected]>
  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         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 }