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