1 // SPDX-License-Identifier: GPL-2.0+ 2 // 3 // Torture test for smp_call_function() and friends. 4 // 5 // Copyright (C) Facebook, 2020. 6 // 7 // Author: Paul E. McKenney <paulmck@kernel.org> 8 9 #define pr_fmt(fmt) fmt 10 11 #include <linux/atomic.h> 12 #include <linux/bitops.h> 13 #include <linux/completion.h> 14 #include <linux/cpu.h> 15 #include <linux/delay.h> 16 #include <linux/err.h> 17 #include <linux/init.h> 18 #include <linux/interrupt.h> 19 #include <linux/kthread.h> 20 #include <linux/kernel.h> 21 #include <linux/mm.h> 22 #include <linux/module.h> 23 #include <linux/moduleparam.h> 24 #include <linux/notifier.h> 25 #include <linux/percpu.h> 26 #include <linux/rcupdate.h> 27 #include <linux/rcupdate_trace.h> 28 #include <linux/reboot.h> 29 #include <linux/sched.h> 30 #include <linux/spinlock.h> 31 #include <linux/smp.h> 32 #include <linux/stat.h> 33 #include <linux/srcu.h> 34 #include <linux/slab.h> 35 #include <linux/torture.h> 36 #include <linux/types.h> 37 38 #define SCFTORT_STRING "scftorture" 39 #define SCFTORT_FLAG SCFTORT_STRING ": " 40 41 #define SCFTORTOUT(s, x...) \ 42 pr_alert(SCFTORT_FLAG s, ## x) 43 44 #define VERBOSE_SCFTORTOUT(s, x...) \ 45 do { if (verbose) pr_alert(SCFTORT_FLAG s, ## x); } while (0) 46 47 #define VERBOSE_SCFTORTOUT_ERRSTRING(s, x...) \ 48 do { if (verbose) pr_alert(SCFTORT_FLAG "!!! " s, ## x); } while (0) 49 50 MODULE_LICENSE("GPL"); 51 MODULE_AUTHOR("Paul E. McKenney <paulmck@kernel.org>"); 52 53 // Wait until there are multiple CPUs before starting test. 54 torture_param(int, holdoff, IS_BUILTIN(CONFIG_SCF_TORTURE_TEST) ? 10 : 0, 55 "Holdoff time before test start (s)"); 56 torture_param(int, longwait, 0, "Include ridiculously long waits? (seconds)"); 57 torture_param(int, nthreads, -1, "# threads, defaults to -1 for all CPUs."); 58 torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)"); 59 torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable"); 60 torture_param(int, shutdown_secs, 0, "Shutdown time (ms), <= zero to disable."); 61 torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s."); 62 torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable"); 63 torture_param(bool, use_cpus_read_lock, 0, "Use cpus_read_lock() to exclude CPU hotplug."); 64 torture_param(int, verbose, 0, "Enable verbose debugging printk()s"); 65 torture_param(int, weight_resched, -1, "Testing weight for resched_cpu() operations."); 66 torture_param(int, weight_single, -1, "Testing weight for single-CPU no-wait operations."); 67 torture_param(int, weight_single_wait, -1, "Testing weight for single-CPU operations."); 68 torture_param(int, weight_many, -1, "Testing weight for multi-CPU no-wait operations."); 69 torture_param(int, weight_many_wait, -1, "Testing weight for multi-CPU operations."); 70 torture_param(int, weight_all, -1, "Testing weight for all-CPU no-wait operations."); 71 torture_param(int, weight_all_wait, -1, "Testing weight for all-CPU operations."); 72 73 char *torture_type = ""; 74 75 #ifdef MODULE 76 # define SCFTORT_SHUTDOWN 0 77 #else 78 # define SCFTORT_SHUTDOWN 1 79 #endif 80 81 torture_param(bool, shutdown, SCFTORT_SHUTDOWN, "Shutdown at end of torture test."); 82 83 struct scf_statistics { 84 struct task_struct *task; 85 int cpu; 86 long long n_resched; 87 long long n_single; 88 long long n_single_ofl; 89 long long n_single_wait; 90 long long n_single_wait_ofl; 91 long long n_many; 92 long long n_many_wait; 93 long long n_all; 94 long long n_all_wait; 95 }; 96 97 static struct scf_statistics *scf_stats_p; 98 static struct task_struct *scf_torture_stats_task; 99 static DEFINE_PER_CPU(long long, scf_invoked_count); 100 101 // Data for random primitive selection 102 #define SCF_PRIM_RESCHED 0 103 #define SCF_PRIM_SINGLE 1 104 #define SCF_PRIM_MANY 2 105 #define SCF_PRIM_ALL 3 106 #define SCF_NPRIMS 7 // Need wait and no-wait versions of each, 107 // except for SCF_PRIM_RESCHED. 108 109 static char *scf_prim_name[] = { 110 "resched_cpu", 111 "smp_call_function_single", 112 "smp_call_function_many", 113 "smp_call_function", 114 }; 115 116 struct scf_selector { 117 unsigned long scfs_weight; 118 int scfs_prim; 119 bool scfs_wait; 120 }; 121 static struct scf_selector scf_sel_array[SCF_NPRIMS]; 122 static int scf_sel_array_len; 123 static unsigned long scf_sel_totweight; 124 125 // Communicate between caller and handler. 126 struct scf_check { 127 bool scfc_in; 128 bool scfc_out; 129 int scfc_cpu; // -1 for not _single(). 130 bool scfc_wait; 131 }; 132 133 // Use to wait for all threads to start. 134 static atomic_t n_started; 135 static atomic_t n_errs; 136 static atomic_t n_mb_in_errs; 137 static atomic_t n_mb_out_errs; 138 static atomic_t n_alloc_errs; 139 static bool scfdone; 140 static char *bangstr = ""; 141 142 static DEFINE_TORTURE_RANDOM_PERCPU(scf_torture_rand); 143 144 extern void resched_cpu(int cpu); // An alternative IPI vector. 145 146 // Print torture statistics. Caller must ensure serialization. 147 static void scf_torture_stats_print(void) 148 { 149 int cpu; 150 int i; 151 long long invoked_count = 0; 152 bool isdone = READ_ONCE(scfdone); 153 struct scf_statistics scfs = {}; 154 155 for_each_possible_cpu(cpu) 156 invoked_count += data_race(per_cpu(scf_invoked_count, cpu)); 157 for (i = 0; i < nthreads; i++) { 158 scfs.n_resched += scf_stats_p[i].n_resched; 159 scfs.n_single += scf_stats_p[i].n_single; 160 scfs.n_single_ofl += scf_stats_p[i].n_single_ofl; 161 scfs.n_single_wait += scf_stats_p[i].n_single_wait; 162 scfs.n_single_wait_ofl += scf_stats_p[i].n_single_wait_ofl; 163 scfs.n_many += scf_stats_p[i].n_many; 164 scfs.n_many_wait += scf_stats_p[i].n_many_wait; 165 scfs.n_all += scf_stats_p[i].n_all; 166 scfs.n_all_wait += scf_stats_p[i].n_all_wait; 167 } 168 if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) || 169 atomic_read(&n_mb_out_errs) || atomic_read(&n_alloc_errs)) 170 bangstr = "!!! "; 171 pr_alert("%s %sscf_invoked_count %s: %lld resched: %lld single: %lld/%lld single_ofl: %lld/%lld many: %lld/%lld all: %lld/%lld ", 172 SCFTORT_FLAG, bangstr, isdone ? "VER" : "ver", invoked_count, scfs.n_resched, 173 scfs.n_single, scfs.n_single_wait, scfs.n_single_ofl, scfs.n_single_wait_ofl, 174 scfs.n_many, scfs.n_many_wait, scfs.n_all, scfs.n_all_wait); 175 torture_onoff_stats(); 176 pr_cont("ste: %d stnmie: %d stnmoe: %d staf: %d\n", atomic_read(&n_errs), 177 atomic_read(&n_mb_in_errs), atomic_read(&n_mb_out_errs), 178 atomic_read(&n_alloc_errs)); 179 } 180 181 // Periodically prints torture statistics, if periodic statistics printing 182 // was specified via the stat_interval module parameter. 183 static int 184 scf_torture_stats(void *arg) 185 { 186 VERBOSE_TOROUT_STRING("scf_torture_stats task started"); 187 do { 188 schedule_timeout_interruptible(stat_interval * HZ); 189 scf_torture_stats_print(); 190 torture_shutdown_absorb("scf_torture_stats"); 191 } while (!torture_must_stop()); 192 torture_kthread_stopping("scf_torture_stats"); 193 return 0; 194 } 195 196 // Add a primitive to the scf_sel_array[]. 197 static void scf_sel_add(unsigned long weight, int prim, bool wait) 198 { 199 struct scf_selector *scfsp = &scf_sel_array[scf_sel_array_len]; 200 201 // If no weight, if array would overflow, if computing three-place 202 // percentages would overflow, or if the scf_prim_name[] array would 203 // overflow, don't bother. In the last three two cases, complain. 204 if (!weight || 205 WARN_ON_ONCE(scf_sel_array_len >= ARRAY_SIZE(scf_sel_array)) || 206 WARN_ON_ONCE(0 - 100000 * weight <= 100000 * scf_sel_totweight) || 207 WARN_ON_ONCE(prim >= ARRAY_SIZE(scf_prim_name))) 208 return; 209 scf_sel_totweight += weight; 210 scfsp->scfs_weight = scf_sel_totweight; 211 scfsp->scfs_prim = prim; 212 scfsp->scfs_wait = wait; 213 scf_sel_array_len++; 214 } 215 216 // Dump out weighting percentages for scf_prim_name[] array. 217 static void scf_sel_dump(void) 218 { 219 int i; 220 unsigned long oldw = 0; 221 struct scf_selector *scfsp; 222 unsigned long w; 223 224 for (i = 0; i < scf_sel_array_len; i++) { 225 scfsp = &scf_sel_array[i]; 226 w = (scfsp->scfs_weight - oldw) * 100000 / scf_sel_totweight; 227 pr_info("%s: %3lu.%03lu %s(%s)\n", __func__, w / 1000, w % 1000, 228 scf_prim_name[scfsp->scfs_prim], 229 scfsp->scfs_wait ? "wait" : "nowait"); 230 oldw = scfsp->scfs_weight; 231 } 232 } 233 234 // Randomly pick a primitive and wait/nowait, based on weightings. 235 static struct scf_selector *scf_sel_rand(struct torture_random_state *trsp) 236 { 237 int i; 238 unsigned long w = torture_random(trsp) % (scf_sel_totweight + 1); 239 240 for (i = 0; i < scf_sel_array_len; i++) 241 if (scf_sel_array[i].scfs_weight >= w) 242 return &scf_sel_array[i]; 243 WARN_ON_ONCE(1); 244 return &scf_sel_array[0]; 245 } 246 247 // Update statistics and occasionally burn up mass quantities of CPU time, 248 // if told to do so via scftorture.longwait. Otherwise, occasionally burn 249 // a little bit. 250 static void scf_handler(void *scfc_in) 251 { 252 int i; 253 int j; 254 unsigned long r = torture_random(this_cpu_ptr(&scf_torture_rand)); 255 struct scf_check *scfcp = scfc_in; 256 257 if (likely(scfcp)) { 258 WRITE_ONCE(scfcp->scfc_out, false); // For multiple receivers. 259 if (WARN_ON_ONCE(unlikely(!READ_ONCE(scfcp->scfc_in)))) 260 atomic_inc(&n_mb_in_errs); 261 } 262 this_cpu_inc(scf_invoked_count); 263 if (longwait <= 0) { 264 if (!(r & 0xffc0)) 265 udelay(r & 0x3f); 266 goto out; 267 } 268 if (r & 0xfff) 269 goto out; 270 r = (r >> 12); 271 if (longwait <= 0) { 272 udelay((r & 0xff) + 1); 273 goto out; 274 } 275 r = r % longwait + 1; 276 for (i = 0; i < r; i++) { 277 for (j = 0; j < 1000; j++) { 278 udelay(1000); 279 cpu_relax(); 280 } 281 } 282 out: 283 if (unlikely(!scfcp)) 284 return; 285 if (scfcp->scfc_wait) 286 WRITE_ONCE(scfcp->scfc_out, true); 287 else 288 kfree(scfcp); 289 } 290 291 // As above, but check for correct CPU. 292 static void scf_handler_1(void *scfc_in) 293 { 294 struct scf_check *scfcp = scfc_in; 295 296 if (likely(scfcp) && WARN_ONCE(smp_processor_id() != scfcp->scfc_cpu, "%s: Wanted CPU %d got CPU %d\n", __func__, scfcp->scfc_cpu, smp_processor_id())) { 297 atomic_inc(&n_errs); 298 } 299 scf_handler(scfcp); 300 } 301 302 // Randomly do an smp_call_function*() invocation. 303 static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_random_state *trsp) 304 { 305 uintptr_t cpu; 306 int ret = 0; 307 struct scf_check *scfcp = NULL; 308 struct scf_selector *scfsp = scf_sel_rand(trsp); 309 310 if (use_cpus_read_lock) 311 cpus_read_lock(); 312 else 313 preempt_disable(); 314 if (scfsp->scfs_prim == SCF_PRIM_SINGLE || scfsp->scfs_wait) { 315 scfcp = kmalloc(sizeof(*scfcp), GFP_ATOMIC); 316 if (WARN_ON_ONCE(!scfcp)) { 317 atomic_inc(&n_alloc_errs); 318 } else { 319 scfcp->scfc_cpu = -1; 320 scfcp->scfc_wait = scfsp->scfs_wait; 321 scfcp->scfc_out = false; 322 } 323 } 324 switch (scfsp->scfs_prim) { 325 case SCF_PRIM_RESCHED: 326 if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST)) { 327 cpu = torture_random(trsp) % nr_cpu_ids; 328 scfp->n_resched++; 329 resched_cpu(cpu); 330 } 331 break; 332 case SCF_PRIM_SINGLE: 333 cpu = torture_random(trsp) % nr_cpu_ids; 334 if (scfsp->scfs_wait) 335 scfp->n_single_wait++; 336 else 337 scfp->n_single++; 338 if (scfcp) { 339 scfcp->scfc_cpu = cpu; 340 barrier(); // Prevent race-reduction compiler optimizations. 341 scfcp->scfc_in = true; 342 } 343 ret = smp_call_function_single(cpu, scf_handler_1, (void *)scfcp, scfsp->scfs_wait); 344 if (ret) { 345 if (scfsp->scfs_wait) 346 scfp->n_single_wait_ofl++; 347 else 348 scfp->n_single_ofl++; 349 kfree(scfcp); 350 scfcp = NULL; 351 } 352 break; 353 case SCF_PRIM_MANY: 354 if (scfsp->scfs_wait) 355 scfp->n_many_wait++; 356 else 357 scfp->n_many++; 358 if (scfcp) { 359 barrier(); // Prevent race-reduction compiler optimizations. 360 scfcp->scfc_in = true; 361 } 362 smp_call_function_many(cpu_online_mask, scf_handler, scfcp, scfsp->scfs_wait); 363 break; 364 case SCF_PRIM_ALL: 365 if (scfsp->scfs_wait) 366 scfp->n_all_wait++; 367 else 368 scfp->n_all++; 369 if (scfcp) { 370 barrier(); // Prevent race-reduction compiler optimizations. 371 scfcp->scfc_in = true; 372 } 373 smp_call_function(scf_handler, scfcp, scfsp->scfs_wait); 374 break; 375 default: 376 WARN_ON_ONCE(1); 377 if (scfcp) 378 scfcp->scfc_out = true; 379 } 380 if (scfcp && scfsp->scfs_wait) { 381 if (WARN_ON_ONCE((num_online_cpus() > 1 || scfsp->scfs_prim == SCF_PRIM_SINGLE) && 382 !scfcp->scfc_out)) 383 atomic_inc(&n_mb_out_errs); // Leak rather than trash! 384 else 385 kfree(scfcp); 386 barrier(); // Prevent race-reduction compiler optimizations. 387 } 388 if (use_cpus_read_lock) 389 cpus_read_unlock(); 390 else 391 preempt_enable(); 392 if (!(torture_random(trsp) & 0xfff)) 393 schedule_timeout_uninterruptible(1); 394 } 395 396 // SCF test kthread. Repeatedly does calls to members of the 397 // smp_call_function() family of functions. 398 static int scftorture_invoker(void *arg) 399 { 400 int cpu; 401 int curcpu; 402 DEFINE_TORTURE_RANDOM(rand); 403 struct scf_statistics *scfp = (struct scf_statistics *)arg; 404 bool was_offline = false; 405 406 VERBOSE_SCFTORTOUT("scftorture_invoker %d: task started", scfp->cpu); 407 cpu = scfp->cpu % nr_cpu_ids; 408 WARN_ON_ONCE(set_cpus_allowed_ptr(current, cpumask_of(cpu))); 409 set_user_nice(current, MAX_NICE); 410 if (holdoff) 411 schedule_timeout_interruptible(holdoff * HZ); 412 413 VERBOSE_SCFTORTOUT("scftorture_invoker %d: Waiting for all SCF torturers from cpu %d", scfp->cpu, raw_smp_processor_id()); 414 415 // Make sure that the CPU is affinitized appropriately during testing. 416 curcpu = raw_smp_processor_id(); 417 WARN_ONCE(curcpu != scfp->cpu % nr_cpu_ids, 418 "%s: Wanted CPU %d, running on %d, nr_cpu_ids = %d\n", 419 __func__, scfp->cpu, curcpu, nr_cpu_ids); 420 421 if (!atomic_dec_return(&n_started)) 422 while (atomic_read_acquire(&n_started)) { 423 if (torture_must_stop()) { 424 VERBOSE_SCFTORTOUT("scftorture_invoker %d ended before starting", scfp->cpu); 425 goto end; 426 } 427 schedule_timeout_uninterruptible(1); 428 } 429 430 VERBOSE_SCFTORTOUT("scftorture_invoker %d started", scfp->cpu); 431 432 do { 433 scftorture_invoke_one(scfp, &rand); 434 while (cpu_is_offline(cpu) && !torture_must_stop()) { 435 schedule_timeout_interruptible(HZ / 5); 436 was_offline = true; 437 } 438 if (was_offline) { 439 set_cpus_allowed_ptr(current, cpumask_of(cpu)); 440 was_offline = false; 441 } 442 cond_resched(); 443 stutter_wait("scftorture_invoker"); 444 } while (!torture_must_stop()); 445 446 VERBOSE_SCFTORTOUT("scftorture_invoker %d ended", scfp->cpu); 447 end: 448 torture_kthread_stopping("scftorture_invoker"); 449 return 0; 450 } 451 452 static void 453 scftorture_print_module_parms(const char *tag) 454 { 455 pr_alert(SCFTORT_FLAG 456 "--- %s: verbose=%d holdoff=%d longwait=%d nthreads=%d onoff_holdoff=%d onoff_interval=%d shutdown_secs=%d stat_interval=%d stutter=%d use_cpus_read_lock=%d, weight_resched=%d, weight_single=%d, weight_single_wait=%d, weight_many=%d, weight_many_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag, 457 verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter, use_cpus_read_lock, weight_resched, weight_single, weight_single_wait, weight_many, weight_many_wait, weight_all, weight_all_wait); 458 } 459 460 static void scf_cleanup_handler(void *unused) 461 { 462 } 463 464 static void scf_torture_cleanup(void) 465 { 466 int i; 467 468 if (torture_cleanup_begin()) 469 return; 470 471 WRITE_ONCE(scfdone, true); 472 if (nthreads) 473 for (i = 0; i < nthreads; i++) 474 torture_stop_kthread("scftorture_invoker", scf_stats_p[i].task); 475 else 476 goto end; 477 smp_call_function(scf_cleanup_handler, NULL, 0); 478 torture_stop_kthread(scf_torture_stats, scf_torture_stats_task); 479 scf_torture_stats_print(); // -After- the stats thread is stopped! 480 kfree(scf_stats_p); // -After- the last stats print has completed! 481 scf_stats_p = NULL; 482 483 if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) || atomic_read(&n_mb_out_errs)) 484 scftorture_print_module_parms("End of test: FAILURE"); 485 else if (torture_onoff_failures()) 486 scftorture_print_module_parms("End of test: LOCK_HOTPLUG"); 487 else 488 scftorture_print_module_parms("End of test: SUCCESS"); 489 490 end: 491 torture_cleanup_end(); 492 } 493 494 static int __init scf_torture_init(void) 495 { 496 long i; 497 int firsterr = 0; 498 unsigned long weight_resched1 = weight_resched; 499 unsigned long weight_single1 = weight_single; 500 unsigned long weight_single_wait1 = weight_single_wait; 501 unsigned long weight_many1 = weight_many; 502 unsigned long weight_many_wait1 = weight_many_wait; 503 unsigned long weight_all1 = weight_all; 504 unsigned long weight_all_wait1 = weight_all_wait; 505 506 if (!torture_init_begin(SCFTORT_STRING, verbose)) 507 return -EBUSY; 508 509 scftorture_print_module_parms("Start of test"); 510 511 if (weight_resched == -1 && weight_single == -1 && weight_single_wait == -1 && 512 weight_many == -1 && weight_many_wait == -1 && 513 weight_all == -1 && weight_all_wait == -1) { 514 weight_resched1 = 2 * nr_cpu_ids; 515 weight_single1 = 2 * nr_cpu_ids; 516 weight_single_wait1 = 2 * nr_cpu_ids; 517 weight_many1 = 2; 518 weight_many_wait1 = 2; 519 weight_all1 = 1; 520 weight_all_wait1 = 1; 521 } else { 522 if (weight_resched == -1) 523 weight_resched1 = 0; 524 if (weight_single == -1) 525 weight_single1 = 0; 526 if (weight_single_wait == -1) 527 weight_single_wait1 = 0; 528 if (weight_many == -1) 529 weight_many1 = 0; 530 if (weight_many_wait == -1) 531 weight_many_wait1 = 0; 532 if (weight_all == -1) 533 weight_all1 = 0; 534 if (weight_all_wait == -1) 535 weight_all_wait1 = 0; 536 } 537 if (weight_single1 == 0 && weight_single_wait1 == 0 && 538 weight_many1 == 0 && weight_many_wait1 == 0 && 539 weight_all1 == 0 && weight_all_wait1 == 0) { 540 VERBOSE_SCFTORTOUT_ERRSTRING("all zero weights makes no sense"); 541 firsterr = -EINVAL; 542 goto unwind; 543 } 544 if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST)) 545 scf_sel_add(weight_resched1, SCF_PRIM_RESCHED, false); 546 else if (weight_resched1) 547 VERBOSE_SCFTORTOUT_ERRSTRING("built as module, weight_resched ignored"); 548 scf_sel_add(weight_single1, SCF_PRIM_SINGLE, false); 549 scf_sel_add(weight_single_wait1, SCF_PRIM_SINGLE, true); 550 scf_sel_add(weight_many1, SCF_PRIM_MANY, false); 551 scf_sel_add(weight_many_wait1, SCF_PRIM_MANY, true); 552 scf_sel_add(weight_all1, SCF_PRIM_ALL, false); 553 scf_sel_add(weight_all_wait1, SCF_PRIM_ALL, true); 554 scf_sel_dump(); 555 556 if (onoff_interval > 0) { 557 firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, NULL); 558 if (firsterr) 559 goto unwind; 560 } 561 if (shutdown_secs > 0) { 562 firsterr = torture_shutdown_init(shutdown_secs, scf_torture_cleanup); 563 if (firsterr) 564 goto unwind; 565 } 566 if (stutter > 0) { 567 firsterr = torture_stutter_init(stutter, stutter); 568 if (firsterr) 569 goto unwind; 570 } 571 572 // Worker tasks invoking smp_call_function(). 573 if (nthreads < 0) 574 nthreads = num_online_cpus(); 575 scf_stats_p = kcalloc(nthreads, sizeof(scf_stats_p[0]), GFP_KERNEL); 576 if (!scf_stats_p) { 577 VERBOSE_SCFTORTOUT_ERRSTRING("out of memory"); 578 firsterr = -ENOMEM; 579 goto unwind; 580 } 581 582 VERBOSE_SCFTORTOUT("Starting %d smp_call_function() threads\n", nthreads); 583 584 atomic_set(&n_started, nthreads); 585 for (i = 0; i < nthreads; i++) { 586 scf_stats_p[i].cpu = i; 587 firsterr = torture_create_kthread(scftorture_invoker, (void *)&scf_stats_p[i], 588 scf_stats_p[i].task); 589 if (firsterr) 590 goto unwind; 591 } 592 if (stat_interval > 0) { 593 firsterr = torture_create_kthread(scf_torture_stats, NULL, scf_torture_stats_task); 594 if (firsterr) 595 goto unwind; 596 } 597 598 torture_init_end(); 599 return 0; 600 601 unwind: 602 torture_init_end(); 603 scf_torture_cleanup(); 604 return firsterr; 605 } 606 607 module_init(scf_torture_init); 608 module_exit(scf_torture_cleanup); 609