1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Read-Copy Update module-based scalability-test facility 4 * 5 * Copyright (C) IBM Corporation, 2015 6 * 7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com> 8 */ 9 10 #define pr_fmt(fmt) fmt 11 12 #include <linux/types.h> 13 #include <linux/kernel.h> 14 #include <linux/init.h> 15 #include <linux/mm.h> 16 #include <linux/module.h> 17 #include <linux/kthread.h> 18 #include <linux/err.h> 19 #include <linux/spinlock.h> 20 #include <linux/smp.h> 21 #include <linux/rcupdate.h> 22 #include <linux/interrupt.h> 23 #include <linux/sched.h> 24 #include <uapi/linux/sched/types.h> 25 #include <linux/atomic.h> 26 #include <linux/bitops.h> 27 #include <linux/completion.h> 28 #include <linux/moduleparam.h> 29 #include <linux/percpu.h> 30 #include <linux/notifier.h> 31 #include <linux/reboot.h> 32 #include <linux/freezer.h> 33 #include <linux/cpu.h> 34 #include <linux/delay.h> 35 #include <linux/stat.h> 36 #include <linux/srcu.h> 37 #include <linux/slab.h> 38 #include <asm/byteorder.h> 39 #include <linux/torture.h> 40 #include <linux/vmalloc.h> 41 #include <linux/rcupdate_trace.h> 42 43 #include "rcu.h" 44 45 MODULE_LICENSE("GPL"); 46 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>"); 47 48 #define SCALE_FLAG "-scale:" 49 #define SCALEOUT_STRING(s) \ 50 pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s) 51 #define VERBOSE_SCALEOUT_STRING(s) \ 52 do { if (verbose) pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s); } while (0) 53 #define VERBOSE_SCALEOUT_ERRSTRING(s) \ 54 do { if (verbose) pr_alert("%s" SCALE_FLAG "!!! %s\n", scale_type, s); } while (0) 55 56 /* 57 * The intended use cases for the nreaders and nwriters module parameters 58 * are as follows: 59 * 60 * 1. Specify only the nr_cpus kernel boot parameter. This will 61 * set both nreaders and nwriters to the value specified by 62 * nr_cpus for a mixed reader/writer test. 63 * 64 * 2. Specify the nr_cpus kernel boot parameter, but set 65 * rcuscale.nreaders to zero. This will set nwriters to the 66 * value specified by nr_cpus for an update-only test. 67 * 68 * 3. Specify the nr_cpus kernel boot parameter, but set 69 * rcuscale.nwriters to zero. This will set nreaders to the 70 * value specified by nr_cpus for a read-only test. 71 * 72 * Various other use cases may of course be specified. 73 * 74 * Note that this test's readers are intended only as a test load for 75 * the writers. The reader scalability statistics will be overly 76 * pessimistic due to the per-critical-section interrupt disabling, 77 * test-end checks, and the pair of calls through pointers. 78 */ 79 80 #ifdef MODULE 81 # define RCUSCALE_SHUTDOWN 0 82 #else 83 # define RCUSCALE_SHUTDOWN 1 84 #endif 85 86 torture_param(bool, gp_async, false, "Use asynchronous GP wait primitives"); 87 torture_param(int, gp_async_max, 1000, "Max # outstanding waits per reader"); 88 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives"); 89 torture_param(int, holdoff, 10, "Holdoff time before test start (s)"); 90 torture_param(int, nreaders, -1, "Number of RCU reader threads"); 91 torture_param(int, nwriters, -1, "Number of RCU updater threads"); 92 torture_param(bool, shutdown, RCUSCALE_SHUTDOWN, 93 "Shutdown at end of scalability tests."); 94 torture_param(int, verbose, 1, "Enable verbose debugging printk()s"); 95 torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable"); 96 torture_param(int, kfree_rcu_test, 0, "Do we run a kfree_rcu() scale test?"); 97 torture_param(int, kfree_mult, 1, "Multiple of kfree_obj size to allocate."); 98 99 static char *scale_type = "rcu"; 100 module_param(scale_type, charp, 0444); 101 MODULE_PARM_DESC(scale_type, "Type of RCU to scalability-test (rcu, srcu, ...)"); 102 103 static int nrealreaders; 104 static int nrealwriters; 105 static struct task_struct **writer_tasks; 106 static struct task_struct **reader_tasks; 107 static struct task_struct *shutdown_task; 108 109 static u64 **writer_durations; 110 static int *writer_n_durations; 111 static atomic_t n_rcu_scale_reader_started; 112 static atomic_t n_rcu_scale_writer_started; 113 static atomic_t n_rcu_scale_writer_finished; 114 static wait_queue_head_t shutdown_wq; 115 static u64 t_rcu_scale_writer_started; 116 static u64 t_rcu_scale_writer_finished; 117 static unsigned long b_rcu_gp_test_started; 118 static unsigned long b_rcu_gp_test_finished; 119 static DEFINE_PER_CPU(atomic_t, n_async_inflight); 120 121 #define MAX_MEAS 10000 122 #define MIN_MEAS 100 123 124 /* 125 * Operations vector for selecting different types of tests. 126 */ 127 128 struct rcu_scale_ops { 129 int ptype; 130 void (*init)(void); 131 void (*cleanup)(void); 132 int (*readlock)(void); 133 void (*readunlock)(int idx); 134 unsigned long (*get_gp_seq)(void); 135 unsigned long (*gp_diff)(unsigned long new, unsigned long old); 136 unsigned long (*exp_completed)(void); 137 void (*async)(struct rcu_head *head, rcu_callback_t func); 138 void (*gp_barrier)(void); 139 void (*sync)(void); 140 void (*exp_sync)(void); 141 const char *name; 142 }; 143 144 static struct rcu_scale_ops *cur_ops; 145 146 /* 147 * Definitions for rcu scalability testing. 148 */ 149 150 static int rcu_scale_read_lock(void) __acquires(RCU) 151 { 152 rcu_read_lock(); 153 return 0; 154 } 155 156 static void rcu_scale_read_unlock(int idx) __releases(RCU) 157 { 158 rcu_read_unlock(); 159 } 160 161 static unsigned long __maybe_unused rcu_no_completed(void) 162 { 163 return 0; 164 } 165 166 static void rcu_sync_scale_init(void) 167 { 168 } 169 170 static struct rcu_scale_ops rcu_ops = { 171 .ptype = RCU_FLAVOR, 172 .init = rcu_sync_scale_init, 173 .readlock = rcu_scale_read_lock, 174 .readunlock = rcu_scale_read_unlock, 175 .get_gp_seq = rcu_get_gp_seq, 176 .gp_diff = rcu_seq_diff, 177 .exp_completed = rcu_exp_batches_completed, 178 .async = call_rcu, 179 .gp_barrier = rcu_barrier, 180 .sync = synchronize_rcu, 181 .exp_sync = synchronize_rcu_expedited, 182 .name = "rcu" 183 }; 184 185 /* 186 * Definitions for srcu scalability testing. 187 */ 188 189 DEFINE_STATIC_SRCU(srcu_ctl_scale); 190 static struct srcu_struct *srcu_ctlp = &srcu_ctl_scale; 191 192 static int srcu_scale_read_lock(void) __acquires(srcu_ctlp) 193 { 194 return srcu_read_lock(srcu_ctlp); 195 } 196 197 static void srcu_scale_read_unlock(int idx) __releases(srcu_ctlp) 198 { 199 srcu_read_unlock(srcu_ctlp, idx); 200 } 201 202 static unsigned long srcu_scale_completed(void) 203 { 204 return srcu_batches_completed(srcu_ctlp); 205 } 206 207 static void srcu_call_rcu(struct rcu_head *head, rcu_callback_t func) 208 { 209 call_srcu(srcu_ctlp, head, func); 210 } 211 212 static void srcu_rcu_barrier(void) 213 { 214 srcu_barrier(srcu_ctlp); 215 } 216 217 static void srcu_scale_synchronize(void) 218 { 219 synchronize_srcu(srcu_ctlp); 220 } 221 222 static void srcu_scale_synchronize_expedited(void) 223 { 224 synchronize_srcu_expedited(srcu_ctlp); 225 } 226 227 static struct rcu_scale_ops srcu_ops = { 228 .ptype = SRCU_FLAVOR, 229 .init = rcu_sync_scale_init, 230 .readlock = srcu_scale_read_lock, 231 .readunlock = srcu_scale_read_unlock, 232 .get_gp_seq = srcu_scale_completed, 233 .gp_diff = rcu_seq_diff, 234 .exp_completed = srcu_scale_completed, 235 .async = srcu_call_rcu, 236 .gp_barrier = srcu_rcu_barrier, 237 .sync = srcu_scale_synchronize, 238 .exp_sync = srcu_scale_synchronize_expedited, 239 .name = "srcu" 240 }; 241 242 static struct srcu_struct srcud; 243 244 static void srcu_sync_scale_init(void) 245 { 246 srcu_ctlp = &srcud; 247 init_srcu_struct(srcu_ctlp); 248 } 249 250 static void srcu_sync_scale_cleanup(void) 251 { 252 cleanup_srcu_struct(srcu_ctlp); 253 } 254 255 static struct rcu_scale_ops srcud_ops = { 256 .ptype = SRCU_FLAVOR, 257 .init = srcu_sync_scale_init, 258 .cleanup = srcu_sync_scale_cleanup, 259 .readlock = srcu_scale_read_lock, 260 .readunlock = srcu_scale_read_unlock, 261 .get_gp_seq = srcu_scale_completed, 262 .gp_diff = rcu_seq_diff, 263 .exp_completed = srcu_scale_completed, 264 .async = srcu_call_rcu, 265 .gp_barrier = srcu_rcu_barrier, 266 .sync = srcu_scale_synchronize, 267 .exp_sync = srcu_scale_synchronize_expedited, 268 .name = "srcud" 269 }; 270 271 /* 272 * Definitions for RCU-tasks scalability testing. 273 */ 274 275 static int tasks_scale_read_lock(void) 276 { 277 return 0; 278 } 279 280 static void tasks_scale_read_unlock(int idx) 281 { 282 } 283 284 static struct rcu_scale_ops tasks_ops = { 285 .ptype = RCU_TASKS_FLAVOR, 286 .init = rcu_sync_scale_init, 287 .readlock = tasks_scale_read_lock, 288 .readunlock = tasks_scale_read_unlock, 289 .get_gp_seq = rcu_no_completed, 290 .gp_diff = rcu_seq_diff, 291 .async = call_rcu_tasks, 292 .gp_barrier = rcu_barrier_tasks, 293 .sync = synchronize_rcu_tasks, 294 .exp_sync = synchronize_rcu_tasks, 295 .name = "tasks" 296 }; 297 298 /* 299 * Definitions for RCU-tasks-trace scalability testing. 300 */ 301 302 static int tasks_trace_scale_read_lock(void) 303 { 304 rcu_read_lock_trace(); 305 return 0; 306 } 307 308 static void tasks_trace_scale_read_unlock(int idx) 309 { 310 rcu_read_unlock_trace(); 311 } 312 313 static struct rcu_scale_ops tasks_tracing_ops = { 314 .ptype = RCU_TASKS_FLAVOR, 315 .init = rcu_sync_scale_init, 316 .readlock = tasks_trace_scale_read_lock, 317 .readunlock = tasks_trace_scale_read_unlock, 318 .get_gp_seq = rcu_no_completed, 319 .gp_diff = rcu_seq_diff, 320 .async = call_rcu_tasks_trace, 321 .gp_barrier = rcu_barrier_tasks_trace, 322 .sync = synchronize_rcu_tasks_trace, 323 .exp_sync = synchronize_rcu_tasks_trace, 324 .name = "tasks-tracing" 325 }; 326 327 static unsigned long rcuscale_seq_diff(unsigned long new, unsigned long old) 328 { 329 if (!cur_ops->gp_diff) 330 return new - old; 331 return cur_ops->gp_diff(new, old); 332 } 333 334 /* 335 * If scalability tests complete, wait for shutdown to commence. 336 */ 337 static void rcu_scale_wait_shutdown(void) 338 { 339 cond_resched_tasks_rcu_qs(); 340 if (atomic_read(&n_rcu_scale_writer_finished) < nrealwriters) 341 return; 342 while (!torture_must_stop()) 343 schedule_timeout_uninterruptible(1); 344 } 345 346 /* 347 * RCU scalability reader kthread. Repeatedly does empty RCU read-side 348 * critical section, minimizing update-side interference. However, the 349 * point of this test is not to evaluate reader scalability, but instead 350 * to serve as a test load for update-side scalability testing. 351 */ 352 static int 353 rcu_scale_reader(void *arg) 354 { 355 unsigned long flags; 356 int idx; 357 long me = (long)arg; 358 359 VERBOSE_SCALEOUT_STRING("rcu_scale_reader task started"); 360 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids)); 361 set_user_nice(current, MAX_NICE); 362 atomic_inc(&n_rcu_scale_reader_started); 363 364 do { 365 local_irq_save(flags); 366 idx = cur_ops->readlock(); 367 cur_ops->readunlock(idx); 368 local_irq_restore(flags); 369 rcu_scale_wait_shutdown(); 370 } while (!torture_must_stop()); 371 torture_kthread_stopping("rcu_scale_reader"); 372 return 0; 373 } 374 375 /* 376 * Callback function for asynchronous grace periods from rcu_scale_writer(). 377 */ 378 static void rcu_scale_async_cb(struct rcu_head *rhp) 379 { 380 atomic_dec(this_cpu_ptr(&n_async_inflight)); 381 kfree(rhp); 382 } 383 384 /* 385 * RCU scale writer kthread. Repeatedly does a grace period. 386 */ 387 static int 388 rcu_scale_writer(void *arg) 389 { 390 int i = 0; 391 int i_max; 392 long me = (long)arg; 393 struct rcu_head *rhp = NULL; 394 bool started = false, done = false, alldone = false; 395 u64 t; 396 u64 *wdp; 397 u64 *wdpp = writer_durations[me]; 398 399 VERBOSE_SCALEOUT_STRING("rcu_scale_writer task started"); 400 WARN_ON(!wdpp); 401 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids)); 402 sched_set_fifo_low(current); 403 404 if (holdoff) 405 schedule_timeout_uninterruptible(holdoff * HZ); 406 407 /* 408 * Wait until rcu_end_inkernel_boot() is called for normal GP tests 409 * so that RCU is not always expedited for normal GP tests. 410 * The system_state test is approximate, but works well in practice. 411 */ 412 while (!gp_exp && system_state != SYSTEM_RUNNING) 413 schedule_timeout_uninterruptible(1); 414 415 t = ktime_get_mono_fast_ns(); 416 if (atomic_inc_return(&n_rcu_scale_writer_started) >= nrealwriters) { 417 t_rcu_scale_writer_started = t; 418 if (gp_exp) { 419 b_rcu_gp_test_started = 420 cur_ops->exp_completed() / 2; 421 } else { 422 b_rcu_gp_test_started = cur_ops->get_gp_seq(); 423 } 424 } 425 426 do { 427 if (writer_holdoff) 428 udelay(writer_holdoff); 429 wdp = &wdpp[i]; 430 *wdp = ktime_get_mono_fast_ns(); 431 if (gp_async) { 432 retry: 433 if (!rhp) 434 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 435 if (rhp && atomic_read(this_cpu_ptr(&n_async_inflight)) < gp_async_max) { 436 atomic_inc(this_cpu_ptr(&n_async_inflight)); 437 cur_ops->async(rhp, rcu_scale_async_cb); 438 rhp = NULL; 439 } else if (!kthread_should_stop()) { 440 cur_ops->gp_barrier(); 441 goto retry; 442 } else { 443 kfree(rhp); /* Because we are stopping. */ 444 } 445 } else if (gp_exp) { 446 cur_ops->exp_sync(); 447 } else { 448 cur_ops->sync(); 449 } 450 t = ktime_get_mono_fast_ns(); 451 *wdp = t - *wdp; 452 i_max = i; 453 if (!started && 454 atomic_read(&n_rcu_scale_writer_started) >= nrealwriters) 455 started = true; 456 if (!done && i >= MIN_MEAS) { 457 done = true; 458 sched_set_normal(current, 0); 459 pr_alert("%s%s rcu_scale_writer %ld has %d measurements\n", 460 scale_type, SCALE_FLAG, me, MIN_MEAS); 461 if (atomic_inc_return(&n_rcu_scale_writer_finished) >= 462 nrealwriters) { 463 schedule_timeout_interruptible(10); 464 rcu_ftrace_dump(DUMP_ALL); 465 SCALEOUT_STRING("Test complete"); 466 t_rcu_scale_writer_finished = t; 467 if (gp_exp) { 468 b_rcu_gp_test_finished = 469 cur_ops->exp_completed() / 2; 470 } else { 471 b_rcu_gp_test_finished = 472 cur_ops->get_gp_seq(); 473 } 474 if (shutdown) { 475 smp_mb(); /* Assign before wake. */ 476 wake_up(&shutdown_wq); 477 } 478 } 479 } 480 if (done && !alldone && 481 atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters) 482 alldone = true; 483 if (started && !alldone && i < MAX_MEAS - 1) 484 i++; 485 rcu_scale_wait_shutdown(); 486 } while (!torture_must_stop()); 487 if (gp_async) { 488 cur_ops->gp_barrier(); 489 } 490 writer_n_durations[me] = i_max; 491 torture_kthread_stopping("rcu_scale_writer"); 492 return 0; 493 } 494 495 static void 496 rcu_scale_print_module_parms(struct rcu_scale_ops *cur_ops, const char *tag) 497 { 498 pr_alert("%s" SCALE_FLAG 499 "--- %s: nreaders=%d nwriters=%d verbose=%d shutdown=%d\n", 500 scale_type, tag, nrealreaders, nrealwriters, verbose, shutdown); 501 } 502 503 static void 504 rcu_scale_cleanup(void) 505 { 506 int i; 507 int j; 508 int ngps = 0; 509 u64 *wdp; 510 u64 *wdpp; 511 512 /* 513 * Would like warning at start, but everything is expedited 514 * during the mid-boot phase, so have to wait till the end. 515 */ 516 if (rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp) 517 VERBOSE_SCALEOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!"); 518 if (rcu_gp_is_normal() && gp_exp) 519 VERBOSE_SCALEOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!"); 520 if (gp_exp && gp_async) 521 VERBOSE_SCALEOUT_ERRSTRING("No expedited async GPs, so went with async!"); 522 523 if (torture_cleanup_begin()) 524 return; 525 if (!cur_ops) { 526 torture_cleanup_end(); 527 return; 528 } 529 530 if (reader_tasks) { 531 for (i = 0; i < nrealreaders; i++) 532 torture_stop_kthread(rcu_scale_reader, 533 reader_tasks[i]); 534 kfree(reader_tasks); 535 } 536 537 if (writer_tasks) { 538 for (i = 0; i < nrealwriters; i++) { 539 torture_stop_kthread(rcu_scale_writer, 540 writer_tasks[i]); 541 if (!writer_n_durations) 542 continue; 543 j = writer_n_durations[i]; 544 pr_alert("%s%s writer %d gps: %d\n", 545 scale_type, SCALE_FLAG, i, j); 546 ngps += j; 547 } 548 pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n", 549 scale_type, SCALE_FLAG, 550 t_rcu_scale_writer_started, t_rcu_scale_writer_finished, 551 t_rcu_scale_writer_finished - 552 t_rcu_scale_writer_started, 553 ngps, 554 rcuscale_seq_diff(b_rcu_gp_test_finished, 555 b_rcu_gp_test_started)); 556 for (i = 0; i < nrealwriters; i++) { 557 if (!writer_durations) 558 break; 559 if (!writer_n_durations) 560 continue; 561 wdpp = writer_durations[i]; 562 if (!wdpp) 563 continue; 564 for (j = 0; j <= writer_n_durations[i]; j++) { 565 wdp = &wdpp[j]; 566 pr_alert("%s%s %4d writer-duration: %5d %llu\n", 567 scale_type, SCALE_FLAG, 568 i, j, *wdp); 569 if (j % 100 == 0) 570 schedule_timeout_uninterruptible(1); 571 } 572 kfree(writer_durations[i]); 573 } 574 kfree(writer_tasks); 575 kfree(writer_durations); 576 kfree(writer_n_durations); 577 } 578 579 /* Do torture-type-specific cleanup operations. */ 580 if (cur_ops->cleanup != NULL) 581 cur_ops->cleanup(); 582 583 torture_cleanup_end(); 584 } 585 586 /* 587 * Return the number if non-negative. If -1, the number of CPUs. 588 * If less than -1, that much less than the number of CPUs, but 589 * at least one. 590 */ 591 static int compute_real(int n) 592 { 593 int nr; 594 595 if (n >= 0) { 596 nr = n; 597 } else { 598 nr = num_online_cpus() + 1 + n; 599 if (nr <= 0) 600 nr = 1; 601 } 602 return nr; 603 } 604 605 /* 606 * RCU scalability shutdown kthread. Just waits to be awakened, then shuts 607 * down system. 608 */ 609 static int 610 rcu_scale_shutdown(void *arg) 611 { 612 wait_event(shutdown_wq, 613 atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters); 614 smp_mb(); /* Wake before output. */ 615 rcu_scale_cleanup(); 616 kernel_power_off(); 617 return -EINVAL; 618 } 619 620 /* 621 * kfree_rcu() scalability tests: Start a kfree_rcu() loop on all CPUs for number 622 * of iterations and measure total time and number of GP for all iterations to complete. 623 */ 624 625 torture_param(int, kfree_nthreads, -1, "Number of threads running loops of kfree_rcu()."); 626 torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees done in an iteration."); 627 torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num allocations and frees."); 628 629 static struct task_struct **kfree_reader_tasks; 630 static int kfree_nrealthreads; 631 static atomic_t n_kfree_scale_thread_started; 632 static atomic_t n_kfree_scale_thread_ended; 633 634 struct kfree_obj { 635 char kfree_obj[8]; 636 struct rcu_head rh; 637 }; 638 639 static int 640 kfree_scale_thread(void *arg) 641 { 642 int i, loop = 0; 643 long me = (long)arg; 644 struct kfree_obj *alloc_ptr; 645 u64 start_time, end_time; 646 long long mem_begin, mem_during = 0; 647 648 VERBOSE_SCALEOUT_STRING("kfree_scale_thread task started"); 649 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids)); 650 set_user_nice(current, MAX_NICE); 651 652 start_time = ktime_get_mono_fast_ns(); 653 654 if (atomic_inc_return(&n_kfree_scale_thread_started) >= kfree_nrealthreads) { 655 if (gp_exp) 656 b_rcu_gp_test_started = cur_ops->exp_completed() / 2; 657 else 658 b_rcu_gp_test_started = cur_ops->get_gp_seq(); 659 } 660 661 do { 662 if (!mem_during) { 663 mem_during = mem_begin = si_mem_available(); 664 } else if (loop % (kfree_loops / 4) == 0) { 665 mem_during = (mem_during + si_mem_available()) / 2; 666 } 667 668 for (i = 0; i < kfree_alloc_num; i++) { 669 alloc_ptr = kmalloc(kfree_mult * sizeof(struct kfree_obj), GFP_KERNEL); 670 if (!alloc_ptr) 671 return -ENOMEM; 672 673 kfree_rcu(alloc_ptr, rh); 674 } 675 676 cond_resched(); 677 } while (!torture_must_stop() && ++loop < kfree_loops); 678 679 if (atomic_inc_return(&n_kfree_scale_thread_ended) >= kfree_nrealthreads) { 680 end_time = ktime_get_mono_fast_ns(); 681 682 if (gp_exp) 683 b_rcu_gp_test_finished = cur_ops->exp_completed() / 2; 684 else 685 b_rcu_gp_test_finished = cur_ops->get_gp_seq(); 686 687 pr_alert("Total time taken by all kfree'ers: %llu ns, loops: %d, batches: %ld, memory footprint: %lldMB\n", 688 (unsigned long long)(end_time - start_time), kfree_loops, 689 rcuscale_seq_diff(b_rcu_gp_test_finished, b_rcu_gp_test_started), 690 (mem_begin - mem_during) >> (20 - PAGE_SHIFT)); 691 692 if (shutdown) { 693 smp_mb(); /* Assign before wake. */ 694 wake_up(&shutdown_wq); 695 } 696 } 697 698 torture_kthread_stopping("kfree_scale_thread"); 699 return 0; 700 } 701 702 static void 703 kfree_scale_cleanup(void) 704 { 705 int i; 706 707 if (torture_cleanup_begin()) 708 return; 709 710 if (kfree_reader_tasks) { 711 for (i = 0; i < kfree_nrealthreads; i++) 712 torture_stop_kthread(kfree_scale_thread, 713 kfree_reader_tasks[i]); 714 kfree(kfree_reader_tasks); 715 } 716 717 torture_cleanup_end(); 718 } 719 720 /* 721 * shutdown kthread. Just waits to be awakened, then shuts down system. 722 */ 723 static int 724 kfree_scale_shutdown(void *arg) 725 { 726 wait_event(shutdown_wq, 727 atomic_read(&n_kfree_scale_thread_ended) >= kfree_nrealthreads); 728 729 smp_mb(); /* Wake before output. */ 730 731 kfree_scale_cleanup(); 732 kernel_power_off(); 733 return -EINVAL; 734 } 735 736 static int __init 737 kfree_scale_init(void) 738 { 739 long i; 740 int firsterr = 0; 741 742 kfree_nrealthreads = compute_real(kfree_nthreads); 743 /* Start up the kthreads. */ 744 if (shutdown) { 745 init_waitqueue_head(&shutdown_wq); 746 firsterr = torture_create_kthread(kfree_scale_shutdown, NULL, 747 shutdown_task); 748 if (firsterr) 749 goto unwind; 750 schedule_timeout_uninterruptible(1); 751 } 752 753 pr_alert("kfree object size=%zu\n", kfree_mult * sizeof(struct kfree_obj)); 754 755 kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]), 756 GFP_KERNEL); 757 if (kfree_reader_tasks == NULL) { 758 firsterr = -ENOMEM; 759 goto unwind; 760 } 761 762 for (i = 0; i < kfree_nrealthreads; i++) { 763 firsterr = torture_create_kthread(kfree_scale_thread, (void *)i, 764 kfree_reader_tasks[i]); 765 if (firsterr) 766 goto unwind; 767 } 768 769 while (atomic_read(&n_kfree_scale_thread_started) < kfree_nrealthreads) 770 schedule_timeout_uninterruptible(1); 771 772 torture_init_end(); 773 return 0; 774 775 unwind: 776 torture_init_end(); 777 kfree_scale_cleanup(); 778 return firsterr; 779 } 780 781 static int __init 782 rcu_scale_init(void) 783 { 784 long i; 785 int firsterr = 0; 786 static struct rcu_scale_ops *scale_ops[] = { 787 &rcu_ops, &srcu_ops, &srcud_ops, &tasks_ops, &tasks_tracing_ops 788 }; 789 790 if (!torture_init_begin(scale_type, verbose)) 791 return -EBUSY; 792 793 /* Process args and announce that the scalability'er is on the job. */ 794 for (i = 0; i < ARRAY_SIZE(scale_ops); i++) { 795 cur_ops = scale_ops[i]; 796 if (strcmp(scale_type, cur_ops->name) == 0) 797 break; 798 } 799 if (i == ARRAY_SIZE(scale_ops)) { 800 pr_alert("rcu-scale: invalid scale type: \"%s\"\n", scale_type); 801 pr_alert("rcu-scale types:"); 802 for (i = 0; i < ARRAY_SIZE(scale_ops); i++) 803 pr_cont(" %s", scale_ops[i]->name); 804 pr_cont("\n"); 805 firsterr = -EINVAL; 806 cur_ops = NULL; 807 goto unwind; 808 } 809 if (cur_ops->init) 810 cur_ops->init(); 811 812 if (kfree_rcu_test) 813 return kfree_scale_init(); 814 815 nrealwriters = compute_real(nwriters); 816 nrealreaders = compute_real(nreaders); 817 atomic_set(&n_rcu_scale_reader_started, 0); 818 atomic_set(&n_rcu_scale_writer_started, 0); 819 atomic_set(&n_rcu_scale_writer_finished, 0); 820 rcu_scale_print_module_parms(cur_ops, "Start of test"); 821 822 /* Start up the kthreads. */ 823 824 if (shutdown) { 825 init_waitqueue_head(&shutdown_wq); 826 firsterr = torture_create_kthread(rcu_scale_shutdown, NULL, 827 shutdown_task); 828 if (firsterr) 829 goto unwind; 830 schedule_timeout_uninterruptible(1); 831 } 832 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), 833 GFP_KERNEL); 834 if (reader_tasks == NULL) { 835 VERBOSE_SCALEOUT_ERRSTRING("out of memory"); 836 firsterr = -ENOMEM; 837 goto unwind; 838 } 839 for (i = 0; i < nrealreaders; i++) { 840 firsterr = torture_create_kthread(rcu_scale_reader, (void *)i, 841 reader_tasks[i]); 842 if (firsterr) 843 goto unwind; 844 } 845 while (atomic_read(&n_rcu_scale_reader_started) < nrealreaders) 846 schedule_timeout_uninterruptible(1); 847 writer_tasks = kcalloc(nrealwriters, sizeof(reader_tasks[0]), 848 GFP_KERNEL); 849 writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations), 850 GFP_KERNEL); 851 writer_n_durations = 852 kcalloc(nrealwriters, sizeof(*writer_n_durations), 853 GFP_KERNEL); 854 if (!writer_tasks || !writer_durations || !writer_n_durations) { 855 VERBOSE_SCALEOUT_ERRSTRING("out of memory"); 856 firsterr = -ENOMEM; 857 goto unwind; 858 } 859 for (i = 0; i < nrealwriters; i++) { 860 writer_durations[i] = 861 kcalloc(MAX_MEAS, sizeof(*writer_durations[i]), 862 GFP_KERNEL); 863 if (!writer_durations[i]) { 864 firsterr = -ENOMEM; 865 goto unwind; 866 } 867 firsterr = torture_create_kthread(rcu_scale_writer, (void *)i, 868 writer_tasks[i]); 869 if (firsterr) 870 goto unwind; 871 } 872 torture_init_end(); 873 return 0; 874 875 unwind: 876 torture_init_end(); 877 rcu_scale_cleanup(); 878 if (shutdown) { 879 WARN_ON(!IS_MODULE(CONFIG_RCU_SCALE_TEST)); 880 kernel_power_off(); 881 } 882 return firsterr; 883 } 884 885 module_init(rcu_scale_init); 886 module_exit(rcu_scale_cleanup); 887