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 #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
  36 atomic_t waiters_blocked = ATOMIC_INITIALIZER;
  37 atomic_t waiters_woken = ATOMIC_INITIALIZER;
  38
  39 futex_t f1 = FUTEX_INITIALIZER;
  40 futex_t f2 = FUTEX_INITIALIZER;
  41 futex_t wake_complete = FUTEX_INITIALIZER;
  42
  43 /* Test option defaults */
  44 static long timeout_ns;
  45 static int broadcast;
  46 static int owner;
  47 static int locked;
  48
  49 struct 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
  57 void 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
  70 int 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
 108 void *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         /* Each thread sleeps for a different amount of time
 115          * This is to avoid races, because we don't lock the
 116          * external mutex here */
 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
 144 void *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
 192 void *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                 /* cond_signal */
 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                 /* we have to loop at least THREAD_MAX times */
 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
 257 void *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
 278 int 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         /* Wait for threads to finish */
 336         /* Store the first error or failure encountered in waiter_ret */
 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
 346 out:
 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
 359 int 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          * FIXME: unit_test is obsolete now that we parse options and the
 402          * various style of runs are done by run.sh - simplify the code and move
 403          * unit_test into main()
 404          */
 405         ret = unit_test(broadcast, locked, owner, timeout_ns);
 406
 407         print_result(TEST_NAME, ret);
 408         return ret;
 409 }