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

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