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 SCALEOUT_ERRSTRING(s) \ 54 pr_alert("%s" SCALE_FLAG "!!! %s\n", scale_type, s) 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 writer"); 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, minruntime, 0, "Minimum run time (s)"); 91 torture_param(int, nreaders, -1, "Number of RCU reader threads"); 92 torture_param(int, nwriters, -1, "Number of RCU updater threads"); 93 torture_param(bool, shutdown, RCUSCALE_SHUTDOWN, 94 "Shutdown at end of scalability tests."); 95 torture_param(int, verbose, 1, "Enable verbose debugging printk()s"); 96 torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable"); 97 torture_param(int, writer_holdoff_jiffies, 0, "Holdoff (jiffies) between GPs, zero to disable"); 98 torture_param(int, kfree_rcu_test, 0, "Do we run a kfree_rcu() scale test?"); 99 torture_param(int, kfree_mult, 1, "Multiple of kfree_obj size to allocate."); 100 torture_param(int, kfree_by_call_rcu, 0, "Use call_rcu() to emulate kfree_rcu()?"); 101 102 static char *scale_type = "rcu"; 103 module_param(scale_type, charp, 0444); 104 MODULE_PARM_DESC(scale_type, "Type of RCU to scalability-test (rcu, srcu, ...)"); 105 106 static int nrealreaders; 107 static int nrealwriters; 108 static struct task_struct **writer_tasks; 109 static struct task_struct **reader_tasks; 110 static struct task_struct *shutdown_task; 111 112 static u64 **writer_durations; 113 static int *writer_n_durations; 114 static atomic_t n_rcu_scale_reader_started; 115 static atomic_t n_rcu_scale_writer_started; 116 static atomic_t n_rcu_scale_writer_finished; 117 static wait_queue_head_t shutdown_wq; 118 static u64 t_rcu_scale_writer_started; 119 static u64 t_rcu_scale_writer_finished; 120 static unsigned long b_rcu_gp_test_started; 121 static unsigned long b_rcu_gp_test_finished; 122 static DEFINE_PER_CPU(atomic_t, n_async_inflight); 123 124 #define MAX_MEAS 10000 125 #define MIN_MEAS 100 126 127 /* 128 * Operations vector for selecting different types of tests. 129 */ 130 131 struct rcu_scale_ops { 132 int ptype; 133 void (*init)(void); 134 void (*cleanup)(void); 135 int (*readlock)(void); 136 void (*readunlock)(int idx); 137 unsigned long (*get_gp_seq)(void); 138 unsigned long (*gp_diff)(unsigned long new, unsigned long old); 139 unsigned long (*exp_completed)(void); 140 void (*async)(struct rcu_head *head, rcu_callback_t func); 141 void (*gp_barrier)(void); 142 void (*sync)(void); 143 void (*exp_sync)(void); 144 struct task_struct *(*rso_gp_kthread)(void); 145 const char *name; 146 }; 147 148 static struct rcu_scale_ops *cur_ops; 149 150 /* 151 * Definitions for rcu scalability testing. 152 */ 153 154 static int rcu_scale_read_lock(void) __acquires(RCU) 155 { 156 rcu_read_lock(); 157 return 0; 158 } 159 160 static void rcu_scale_read_unlock(int idx) __releases(RCU) 161 { 162 rcu_read_unlock(); 163 } 164 165 static unsigned long __maybe_unused rcu_no_completed(void) 166 { 167 return 0; 168 } 169 170 static void rcu_sync_scale_init(void) 171 { 172 } 173 174 static struct rcu_scale_ops rcu_ops = { 175 .ptype = RCU_FLAVOR, 176 .init = rcu_sync_scale_init, 177 .readlock = rcu_scale_read_lock, 178 .readunlock = rcu_scale_read_unlock, 179 .get_gp_seq = rcu_get_gp_seq, 180 .gp_diff = rcu_seq_diff, 181 .exp_completed = rcu_exp_batches_completed, 182 .async = call_rcu_hurry, 183 .gp_barrier = rcu_barrier, 184 .sync = synchronize_rcu, 185 .exp_sync = synchronize_rcu_expedited, 186 .name = "rcu" 187 }; 188 189 /* 190 * Definitions for srcu scalability testing. 191 */ 192 193 DEFINE_STATIC_SRCU(srcu_ctl_scale); 194 static struct srcu_struct *srcu_ctlp = &srcu_ctl_scale; 195 196 static int srcu_scale_read_lock(void) __acquires(srcu_ctlp) 197 { 198 return srcu_read_lock(srcu_ctlp); 199 } 200 201 static void srcu_scale_read_unlock(int idx) __releases(srcu_ctlp) 202 { 203 srcu_read_unlock(srcu_ctlp, idx); 204 } 205 206 static unsigned long srcu_scale_completed(void) 207 { 208 return srcu_batches_completed(srcu_ctlp); 209 } 210 211 static void srcu_call_rcu(struct rcu_head *head, rcu_callback_t func) 212 { 213 call_srcu(srcu_ctlp, head, func); 214 } 215 216 static void srcu_rcu_barrier(void) 217 { 218 srcu_barrier(srcu_ctlp); 219 } 220 221 static void srcu_scale_synchronize(void) 222 { 223 synchronize_srcu(srcu_ctlp); 224 } 225 226 static void srcu_scale_synchronize_expedited(void) 227 { 228 synchronize_srcu_expedited(srcu_ctlp); 229 } 230 231 static struct rcu_scale_ops srcu_ops = { 232 .ptype = SRCU_FLAVOR, 233 .init = rcu_sync_scale_init, 234 .readlock = srcu_scale_read_lock, 235 .readunlock = srcu_scale_read_unlock, 236 .get_gp_seq = srcu_scale_completed, 237 .gp_diff = rcu_seq_diff, 238 .exp_completed = srcu_scale_completed, 239 .async = srcu_call_rcu, 240 .gp_barrier = srcu_rcu_barrier, 241 .sync = srcu_scale_synchronize, 242 .exp_sync = srcu_scale_synchronize_expedited, 243 .name = "srcu" 244 }; 245 246 static struct srcu_struct srcud; 247 248 static void srcu_sync_scale_init(void) 249 { 250 srcu_ctlp = &srcud; 251 init_srcu_struct(srcu_ctlp); 252 } 253 254 static void srcu_sync_scale_cleanup(void) 255 { 256 cleanup_srcu_struct(srcu_ctlp); 257 } 258 259 static struct rcu_scale_ops srcud_ops = { 260 .ptype = SRCU_FLAVOR, 261 .init = srcu_sync_scale_init, 262 .cleanup = srcu_sync_scale_cleanup, 263 .readlock = srcu_scale_read_lock, 264 .readunlock = srcu_scale_read_unlock, 265 .get_gp_seq = srcu_scale_completed, 266 .gp_diff = rcu_seq_diff, 267 .exp_completed = srcu_scale_completed, 268 .async = srcu_call_rcu, 269 .gp_barrier = srcu_rcu_barrier, 270 .sync = srcu_scale_synchronize, 271 .exp_sync = srcu_scale_synchronize_expedited, 272 .name = "srcud" 273 }; 274 275 #ifdef CONFIG_TASKS_RCU 276 277 /* 278 * Definitions for RCU-tasks scalability testing. 279 */ 280 281 static int tasks_scale_read_lock(void) 282 { 283 return 0; 284 } 285 286 static void tasks_scale_read_unlock(int idx) 287 { 288 } 289 290 static struct rcu_scale_ops tasks_ops = { 291 .ptype = RCU_TASKS_FLAVOR, 292 .init = rcu_sync_scale_init, 293 .readlock = tasks_scale_read_lock, 294 .readunlock = tasks_scale_read_unlock, 295 .get_gp_seq = rcu_no_completed, 296 .gp_diff = rcu_seq_diff, 297 .async = call_rcu_tasks, 298 .gp_barrier = rcu_barrier_tasks, 299 .sync = synchronize_rcu_tasks, 300 .exp_sync = synchronize_rcu_tasks, 301 .rso_gp_kthread = get_rcu_tasks_gp_kthread, 302 .name = "tasks" 303 }; 304 305 #define TASKS_OPS &tasks_ops, 306 307 #else // #ifdef CONFIG_TASKS_RCU 308 309 #define TASKS_OPS 310 311 #endif // #else // #ifdef CONFIG_TASKS_RCU 312 313 #ifdef CONFIG_TASKS_RUDE_RCU 314 315 /* 316 * Definitions for RCU-tasks-rude scalability testing. 317 */ 318 319 static int tasks_rude_scale_read_lock(void) 320 { 321 return 0; 322 } 323 324 static void tasks_rude_scale_read_unlock(int idx) 325 { 326 } 327 328 static struct rcu_scale_ops tasks_rude_ops = { 329 .ptype = RCU_TASKS_RUDE_FLAVOR, 330 .init = rcu_sync_scale_init, 331 .readlock = tasks_rude_scale_read_lock, 332 .readunlock = tasks_rude_scale_read_unlock, 333 .get_gp_seq = rcu_no_completed, 334 .gp_diff = rcu_seq_diff, 335 .async = call_rcu_tasks_rude, 336 .gp_barrier = rcu_barrier_tasks_rude, 337 .sync = synchronize_rcu_tasks_rude, 338 .exp_sync = synchronize_rcu_tasks_rude, 339 .rso_gp_kthread = get_rcu_tasks_rude_gp_kthread, 340 .name = "tasks-rude" 341 }; 342 343 #define TASKS_RUDE_OPS &tasks_rude_ops, 344 345 #else // #ifdef CONFIG_TASKS_RUDE_RCU 346 347 #define TASKS_RUDE_OPS 348 349 #endif // #else // #ifdef CONFIG_TASKS_RUDE_RCU 350 351 #ifdef CONFIG_TASKS_TRACE_RCU 352 353 /* 354 * Definitions for RCU-tasks-trace scalability testing. 355 */ 356 357 static int tasks_trace_scale_read_lock(void) 358 { 359 rcu_read_lock_trace(); 360 return 0; 361 } 362 363 static void tasks_trace_scale_read_unlock(int idx) 364 { 365 rcu_read_unlock_trace(); 366 } 367 368 static struct rcu_scale_ops tasks_tracing_ops = { 369 .ptype = RCU_TASKS_FLAVOR, 370 .init = rcu_sync_scale_init, 371 .readlock = tasks_trace_scale_read_lock, 372 .readunlock = tasks_trace_scale_read_unlock, 373 .get_gp_seq = rcu_no_completed, 374 .gp_diff = rcu_seq_diff, 375 .async = call_rcu_tasks_trace, 376 .gp_barrier = rcu_barrier_tasks_trace, 377 .sync = synchronize_rcu_tasks_trace, 378 .exp_sync = synchronize_rcu_tasks_trace, 379 .rso_gp_kthread = get_rcu_tasks_trace_gp_kthread, 380 .name = "tasks-tracing" 381 }; 382 383 #define TASKS_TRACING_OPS &tasks_tracing_ops, 384 385 #else // #ifdef CONFIG_TASKS_TRACE_RCU 386 387 #define TASKS_TRACING_OPS 388 389 #endif // #else // #ifdef CONFIG_TASKS_TRACE_RCU 390 391 static unsigned long rcuscale_seq_diff(unsigned long new, unsigned long old) 392 { 393 if (!cur_ops->gp_diff) 394 return new - old; 395 return cur_ops->gp_diff(new, old); 396 } 397 398 /* 399 * If scalability tests complete, wait for shutdown to commence. 400 */ 401 static void rcu_scale_wait_shutdown(void) 402 { 403 cond_resched_tasks_rcu_qs(); 404 if (atomic_read(&n_rcu_scale_writer_finished) < nrealwriters) 405 return; 406 while (!torture_must_stop()) 407 schedule_timeout_uninterruptible(1); 408 } 409 410 /* 411 * RCU scalability reader kthread. Repeatedly does empty RCU read-side 412 * critical section, minimizing update-side interference. However, the 413 * point of this test is not to evaluate reader scalability, but instead 414 * to serve as a test load for update-side scalability testing. 415 */ 416 static int 417 rcu_scale_reader(void *arg) 418 { 419 unsigned long flags; 420 int idx; 421 long me = (long)arg; 422 423 VERBOSE_SCALEOUT_STRING("rcu_scale_reader task started"); 424 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids)); 425 set_user_nice(current, MAX_NICE); 426 atomic_inc(&n_rcu_scale_reader_started); 427 428 do { 429 local_irq_save(flags); 430 idx = cur_ops->readlock(); 431 cur_ops->readunlock(idx); 432 local_irq_restore(flags); 433 rcu_scale_wait_shutdown(); 434 } while (!torture_must_stop()); 435 torture_kthread_stopping("rcu_scale_reader"); 436 return 0; 437 } 438 439 /* 440 * Callback function for asynchronous grace periods from rcu_scale_writer(). 441 */ 442 static void rcu_scale_async_cb(struct rcu_head *rhp) 443 { 444 atomic_dec(this_cpu_ptr(&n_async_inflight)); 445 kfree(rhp); 446 } 447 448 /* 449 * RCU scale writer kthread. Repeatedly does a grace period. 450 */ 451 static int 452 rcu_scale_writer(void *arg) 453 { 454 int i = 0; 455 int i_max; 456 unsigned long jdone; 457 long me = (long)arg; 458 struct rcu_head *rhp = NULL; 459 bool started = false, done = false, alldone = false; 460 u64 t; 461 DEFINE_TORTURE_RANDOM(tr); 462 u64 *wdp; 463 u64 *wdpp = writer_durations[me]; 464 465 VERBOSE_SCALEOUT_STRING("rcu_scale_writer task started"); 466 WARN_ON(!wdpp); 467 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids)); 468 current->flags |= PF_NO_SETAFFINITY; 469 sched_set_fifo_low(current); 470 471 if (holdoff) 472 schedule_timeout_idle(holdoff * HZ); 473 474 /* 475 * Wait until rcu_end_inkernel_boot() is called for normal GP tests 476 * so that RCU is not always expedited for normal GP tests. 477 * The system_state test is approximate, but works well in practice. 478 */ 479 while (!gp_exp && system_state != SYSTEM_RUNNING) 480 schedule_timeout_uninterruptible(1); 481 482 t = ktime_get_mono_fast_ns(); 483 if (atomic_inc_return(&n_rcu_scale_writer_started) >= nrealwriters) { 484 t_rcu_scale_writer_started = t; 485 if (gp_exp) { 486 b_rcu_gp_test_started = 487 cur_ops->exp_completed() / 2; 488 } else { 489 b_rcu_gp_test_started = cur_ops->get_gp_seq(); 490 } 491 } 492 493 jdone = jiffies + minruntime * HZ; 494 do { 495 if (writer_holdoff) 496 udelay(writer_holdoff); 497 if (writer_holdoff_jiffies) 498 schedule_timeout_idle(torture_random(&tr) % writer_holdoff_jiffies + 1); 499 wdp = &wdpp[i]; 500 *wdp = ktime_get_mono_fast_ns(); 501 if (gp_async) { 502 retry: 503 if (!rhp) 504 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL); 505 if (rhp && atomic_read(this_cpu_ptr(&n_async_inflight)) < gp_async_max) { 506 atomic_inc(this_cpu_ptr(&n_async_inflight)); 507 cur_ops->async(rhp, rcu_scale_async_cb); 508 rhp = NULL; 509 } else if (!kthread_should_stop()) { 510 cur_ops->gp_barrier(); 511 goto retry; 512 } else { 513 kfree(rhp); /* Because we are stopping. */ 514 } 515 } else if (gp_exp) { 516 cur_ops->exp_sync(); 517 } else { 518 cur_ops->sync(); 519 } 520 t = ktime_get_mono_fast_ns(); 521 *wdp = t - *wdp; 522 i_max = i; 523 if (!started && 524 atomic_read(&n_rcu_scale_writer_started) >= nrealwriters) 525 started = true; 526 if (!done && i >= MIN_MEAS && time_after(jiffies, jdone)) { 527 done = true; 528 sched_set_normal(current, 0); 529 pr_alert("%s%s rcu_scale_writer %ld has %d measurements\n", 530 scale_type, SCALE_FLAG, me, MIN_MEAS); 531 if (atomic_inc_return(&n_rcu_scale_writer_finished) >= 532 nrealwriters) { 533 schedule_timeout_interruptible(10); 534 rcu_ftrace_dump(DUMP_ALL); 535 SCALEOUT_STRING("Test complete"); 536 t_rcu_scale_writer_finished = t; 537 if (gp_exp) { 538 b_rcu_gp_test_finished = 539 cur_ops->exp_completed() / 2; 540 } else { 541 b_rcu_gp_test_finished = 542 cur_ops->get_gp_seq(); 543 } 544 if (shutdown) { 545 smp_mb(); /* Assign before wake. */ 546 wake_up(&shutdown_wq); 547 } 548 } 549 } 550 if (done && !alldone && 551 atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters) 552 alldone = true; 553 if (started && !alldone && i < MAX_MEAS - 1) 554 i++; 555 rcu_scale_wait_shutdown(); 556 } while (!torture_must_stop()); 557 if (gp_async) { 558 cur_ops->gp_barrier(); 559 } 560 writer_n_durations[me] = i_max + 1; 561 torture_kthread_stopping("rcu_scale_writer"); 562 return 0; 563 } 564 565 static void 566 rcu_scale_print_module_parms(struct rcu_scale_ops *cur_ops, const char *tag) 567 { 568 pr_alert("%s" SCALE_FLAG 569 "--- %s: gp_async=%d gp_async_max=%d gp_exp=%d holdoff=%d minruntime=%d nreaders=%d nwriters=%d writer_holdoff=%d writer_holdoff_jiffies=%d verbose=%d shutdown=%d\n", 570 scale_type, tag, gp_async, gp_async_max, gp_exp, holdoff, minruntime, nrealreaders, nrealwriters, writer_holdoff, writer_holdoff_jiffies, verbose, shutdown); 571 } 572 573 /* 574 * Return the number if non-negative. If -1, the number of CPUs. 575 * If less than -1, that much less than the number of CPUs, but 576 * at least one. 577 */ 578 static int compute_real(int n) 579 { 580 int nr; 581 582 if (n >= 0) { 583 nr = n; 584 } else { 585 nr = num_online_cpus() + 1 + n; 586 if (nr <= 0) 587 nr = 1; 588 } 589 return nr; 590 } 591 592 /* 593 * kfree_rcu() scalability tests: Start a kfree_rcu() loop on all CPUs for number 594 * of iterations and measure total time and number of GP for all iterations to complete. 595 */ 596 597 torture_param(int, kfree_nthreads, -1, "Number of threads running loops of kfree_rcu()."); 598 torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees done in an iteration."); 599 torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num allocations and frees."); 600 torture_param(bool, kfree_rcu_test_double, false, "Do we run a kfree_rcu() double-argument scale test?"); 601 torture_param(bool, kfree_rcu_test_single, false, "Do we run a kfree_rcu() single-argument scale test?"); 602 603 static struct task_struct **kfree_reader_tasks; 604 static int kfree_nrealthreads; 605 static atomic_t n_kfree_scale_thread_started; 606 static atomic_t n_kfree_scale_thread_ended; 607 static struct task_struct *kthread_tp; 608 static u64 kthread_stime; 609 610 struct kfree_obj { 611 char kfree_obj[8]; 612 struct rcu_head rh; 613 }; 614 615 /* Used if doing RCU-kfree'ing via call_rcu(). */ 616 static void kfree_call_rcu(struct rcu_head *rh) 617 { 618 struct kfree_obj *obj = container_of(rh, struct kfree_obj, rh); 619 620 kfree(obj); 621 } 622 623 static int 624 kfree_scale_thread(void *arg) 625 { 626 int i, loop = 0; 627 long me = (long)arg; 628 struct kfree_obj *alloc_ptr; 629 u64 start_time, end_time; 630 long long mem_begin, mem_during = 0; 631 bool kfree_rcu_test_both; 632 DEFINE_TORTURE_RANDOM(tr); 633 634 VERBOSE_SCALEOUT_STRING("kfree_scale_thread task started"); 635 set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids)); 636 set_user_nice(current, MAX_NICE); 637 kfree_rcu_test_both = (kfree_rcu_test_single == kfree_rcu_test_double); 638 639 start_time = ktime_get_mono_fast_ns(); 640 641 if (atomic_inc_return(&n_kfree_scale_thread_started) >= kfree_nrealthreads) { 642 if (gp_exp) 643 b_rcu_gp_test_started = cur_ops->exp_completed() / 2; 644 else 645 b_rcu_gp_test_started = cur_ops->get_gp_seq(); 646 } 647 648 do { 649 if (!mem_during) { 650 mem_during = mem_begin = si_mem_available(); 651 } else if (loop % (kfree_loops / 4) == 0) { 652 mem_during = (mem_during + si_mem_available()) / 2; 653 } 654 655 for (i = 0; i < kfree_alloc_num; i++) { 656 alloc_ptr = kmalloc(kfree_mult * sizeof(struct kfree_obj), GFP_KERNEL); 657 if (!alloc_ptr) 658 return -ENOMEM; 659 660 if (kfree_by_call_rcu) { 661 call_rcu(&(alloc_ptr->rh), kfree_call_rcu); 662 continue; 663 } 664 665 // By default kfree_rcu_test_single and kfree_rcu_test_double are 666 // initialized to false. If both have the same value (false or true) 667 // both are randomly tested, otherwise only the one with value true 668 // is tested. 669 if ((kfree_rcu_test_single && !kfree_rcu_test_double) || 670 (kfree_rcu_test_both && torture_random(&tr) & 0x800)) 671 kfree_rcu_mightsleep(alloc_ptr); 672 else 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_idle(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 // Used if doing RCU-kfree'ing via call_rcu(). 737 static unsigned long jiffies_at_lazy_cb; 738 static struct rcu_head lazy_test1_rh; 739 static int rcu_lazy_test1_cb_called; 740 static void call_rcu_lazy_test1(struct rcu_head *rh) 741 { 742 jiffies_at_lazy_cb = jiffies; 743 WRITE_ONCE(rcu_lazy_test1_cb_called, 1); 744 } 745 746 static int __init 747 kfree_scale_init(void) 748 { 749 int firsterr = 0; 750 long i; 751 unsigned long jif_start; 752 unsigned long orig_jif; 753 754 pr_alert("%s" SCALE_FLAG 755 "--- kfree_rcu_test: kfree_mult=%d kfree_by_call_rcu=%d kfree_nthreads=%d kfree_alloc_num=%d kfree_loops=%d kfree_rcu_test_double=%d kfree_rcu_test_single=%d\n", 756 scale_type, kfree_mult, kfree_by_call_rcu, kfree_nthreads, kfree_alloc_num, kfree_loops, kfree_rcu_test_double, kfree_rcu_test_single); 757 758 // Also, do a quick self-test to ensure laziness is as much as 759 // expected. 760 if (kfree_by_call_rcu && !IS_ENABLED(CONFIG_RCU_LAZY)) { 761 pr_alert("CONFIG_RCU_LAZY is disabled, falling back to kfree_rcu() for delayed RCU kfree'ing\n"); 762 kfree_by_call_rcu = 0; 763 } 764 765 if (kfree_by_call_rcu) { 766 /* do a test to check the timeout. */ 767 orig_jif = rcu_lazy_get_jiffies_till_flush(); 768 769 rcu_lazy_set_jiffies_till_flush(2 * HZ); 770 rcu_barrier(); 771 772 jif_start = jiffies; 773 jiffies_at_lazy_cb = 0; 774 call_rcu(&lazy_test1_rh, call_rcu_lazy_test1); 775 776 smp_cond_load_relaxed(&rcu_lazy_test1_cb_called, VAL == 1); 777 778 rcu_lazy_set_jiffies_till_flush(orig_jif); 779 780 if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start < 2 * HZ)) { 781 pr_alert("ERROR: call_rcu() CBs are not being lazy as expected!\n"); 782 WARN_ON_ONCE(1); 783 return -1; 784 } 785 786 if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start > 3 * HZ)) { 787 pr_alert("ERROR: call_rcu() CBs are being too lazy!\n"); 788 WARN_ON_ONCE(1); 789 return -1; 790 } 791 } 792 793 kfree_nrealthreads = compute_real(kfree_nthreads); 794 /* Start up the kthreads. */ 795 if (shutdown) { 796 init_waitqueue_head(&shutdown_wq); 797 firsterr = torture_create_kthread(kfree_scale_shutdown, NULL, 798 shutdown_task); 799 if (torture_init_error(firsterr)) 800 goto unwind; 801 schedule_timeout_uninterruptible(1); 802 } 803 804 pr_alert("kfree object size=%zu, kfree_by_call_rcu=%d\n", 805 kfree_mult * sizeof(struct kfree_obj), 806 kfree_by_call_rcu); 807 808 kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]), 809 GFP_KERNEL); 810 if (kfree_reader_tasks == NULL) { 811 firsterr = -ENOMEM; 812 goto unwind; 813 } 814 815 for (i = 0; i < kfree_nrealthreads; i++) { 816 firsterr = torture_create_kthread(kfree_scale_thread, (void *)i, 817 kfree_reader_tasks[i]); 818 if (torture_init_error(firsterr)) 819 goto unwind; 820 } 821 822 while (atomic_read(&n_kfree_scale_thread_started) < kfree_nrealthreads) 823 schedule_timeout_uninterruptible(1); 824 825 torture_init_end(); 826 return 0; 827 828 unwind: 829 torture_init_end(); 830 kfree_scale_cleanup(); 831 return firsterr; 832 } 833 834 static void 835 rcu_scale_cleanup(void) 836 { 837 int i; 838 int j; 839 int ngps = 0; 840 u64 *wdp; 841 u64 *wdpp; 842 843 /* 844 * Would like warning at start, but everything is expedited 845 * during the mid-boot phase, so have to wait till the end. 846 */ 847 if (rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp) 848 SCALEOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!"); 849 if (rcu_gp_is_normal() && gp_exp) 850 SCALEOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!"); 851 if (gp_exp && gp_async) 852 SCALEOUT_ERRSTRING("No expedited async GPs, so went with async!"); 853 854 // If built-in, just report all of the GP kthread's CPU time. 855 if (IS_BUILTIN(CONFIG_RCU_SCALE_TEST) && !kthread_tp && cur_ops->rso_gp_kthread) 856 kthread_tp = cur_ops->rso_gp_kthread(); 857 if (kthread_tp) { 858 u32 ns; 859 u64 us; 860 861 kthread_stime = kthread_tp->stime - kthread_stime; 862 us = div_u64_rem(kthread_stime, 1000, &ns); 863 pr_info("rcu_scale: Grace-period kthread CPU time: %llu.%03u us\n", us, ns); 864 show_rcu_gp_kthreads(); 865 } 866 if (kfree_rcu_test) { 867 kfree_scale_cleanup(); 868 return; 869 } 870 871 if (torture_cleanup_begin()) 872 return; 873 if (!cur_ops) { 874 torture_cleanup_end(); 875 return; 876 } 877 878 if (reader_tasks) { 879 for (i = 0; i < nrealreaders; i++) 880 torture_stop_kthread(rcu_scale_reader, 881 reader_tasks[i]); 882 kfree(reader_tasks); 883 } 884 885 if (writer_tasks) { 886 for (i = 0; i < nrealwriters; i++) { 887 torture_stop_kthread(rcu_scale_writer, 888 writer_tasks[i]); 889 if (!writer_n_durations) 890 continue; 891 j = writer_n_durations[i]; 892 pr_alert("%s%s writer %d gps: %d\n", 893 scale_type, SCALE_FLAG, i, j); 894 ngps += j; 895 } 896 pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n", 897 scale_type, SCALE_FLAG, 898 t_rcu_scale_writer_started, t_rcu_scale_writer_finished, 899 t_rcu_scale_writer_finished - 900 t_rcu_scale_writer_started, 901 ngps, 902 rcuscale_seq_diff(b_rcu_gp_test_finished, 903 b_rcu_gp_test_started)); 904 for (i = 0; i < nrealwriters; i++) { 905 if (!writer_durations) 906 break; 907 if (!writer_n_durations) 908 continue; 909 wdpp = writer_durations[i]; 910 if (!wdpp) 911 continue; 912 for (j = 0; j < writer_n_durations[i]; j++) { 913 wdp = &wdpp[j]; 914 pr_alert("%s%s %4d writer-duration: %5d %llu\n", 915 scale_type, SCALE_FLAG, 916 i, j, *wdp); 917 if (j % 100 == 0) 918 schedule_timeout_uninterruptible(1); 919 } 920 kfree(writer_durations[i]); 921 } 922 kfree(writer_tasks); 923 kfree(writer_durations); 924 kfree(writer_n_durations); 925 } 926 927 /* Do torture-type-specific cleanup operations. */ 928 if (cur_ops->cleanup != NULL) 929 cur_ops->cleanup(); 930 931 torture_cleanup_end(); 932 } 933 934 /* 935 * RCU scalability shutdown kthread. Just waits to be awakened, then shuts 936 * down system. 937 */ 938 static int 939 rcu_scale_shutdown(void *arg) 940 { 941 wait_event_idle(shutdown_wq, atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters); 942 smp_mb(); /* Wake before output. */ 943 rcu_scale_cleanup(); 944 kernel_power_off(); 945 return -EINVAL; 946 } 947 948 static int __init 949 rcu_scale_init(void) 950 { 951 long i; 952 int firsterr = 0; 953 static struct rcu_scale_ops *scale_ops[] = { 954 &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS 955 }; 956 957 if (!torture_init_begin(scale_type, verbose)) 958 return -EBUSY; 959 960 /* Process args and announce that the scalability'er is on the job. */ 961 for (i = 0; i < ARRAY_SIZE(scale_ops); i++) { 962 cur_ops = scale_ops[i]; 963 if (strcmp(scale_type, cur_ops->name) == 0) 964 break; 965 } 966 if (i == ARRAY_SIZE(scale_ops)) { 967 pr_alert("rcu-scale: invalid scale type: \"%s\"\n", scale_type); 968 pr_alert("rcu-scale types:"); 969 for (i = 0; i < ARRAY_SIZE(scale_ops); i++) 970 pr_cont(" %s", scale_ops[i]->name); 971 pr_cont("\n"); 972 firsterr = -EINVAL; 973 cur_ops = NULL; 974 goto unwind; 975 } 976 if (cur_ops->init) 977 cur_ops->init(); 978 979 if (cur_ops->rso_gp_kthread) { 980 kthread_tp = cur_ops->rso_gp_kthread(); 981 if (kthread_tp) 982 kthread_stime = kthread_tp->stime; 983 } 984 if (kfree_rcu_test) 985 return kfree_scale_init(); 986 987 nrealwriters = compute_real(nwriters); 988 nrealreaders = compute_real(nreaders); 989 atomic_set(&n_rcu_scale_reader_started, 0); 990 atomic_set(&n_rcu_scale_writer_started, 0); 991 atomic_set(&n_rcu_scale_writer_finished, 0); 992 rcu_scale_print_module_parms(cur_ops, "Start of test"); 993 994 /* Start up the kthreads. */ 995 996 if (shutdown) { 997 init_waitqueue_head(&shutdown_wq); 998 firsterr = torture_create_kthread(rcu_scale_shutdown, NULL, 999 shutdown_task); 1000 if (torture_init_error(firsterr)) 1001 goto unwind; 1002 schedule_timeout_uninterruptible(1); 1003 } 1004 reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]), 1005 GFP_KERNEL); 1006 if (reader_tasks == NULL) { 1007 SCALEOUT_ERRSTRING("out of memory"); 1008 firsterr = -ENOMEM; 1009 goto unwind; 1010 } 1011 for (i = 0; i < nrealreaders; i++) { 1012 firsterr = torture_create_kthread(rcu_scale_reader, (void *)i, 1013 reader_tasks[i]); 1014 if (torture_init_error(firsterr)) 1015 goto unwind; 1016 } 1017 while (atomic_read(&n_rcu_scale_reader_started) < nrealreaders) 1018 schedule_timeout_uninterruptible(1); 1019 writer_tasks = kcalloc(nrealwriters, sizeof(reader_tasks[0]), 1020 GFP_KERNEL); 1021 writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations), 1022 GFP_KERNEL); 1023 writer_n_durations = 1024 kcalloc(nrealwriters, sizeof(*writer_n_durations), 1025 GFP_KERNEL); 1026 if (!writer_tasks || !writer_durations || !writer_n_durations) { 1027 SCALEOUT_ERRSTRING("out of memory"); 1028 firsterr = -ENOMEM; 1029 goto unwind; 1030 } 1031 for (i = 0; i < nrealwriters; i++) { 1032 writer_durations[i] = 1033 kcalloc(MAX_MEAS, sizeof(*writer_durations[i]), 1034 GFP_KERNEL); 1035 if (!writer_durations[i]) { 1036 firsterr = -ENOMEM; 1037 goto unwind; 1038 } 1039 firsterr = torture_create_kthread(rcu_scale_writer, (void *)i, 1040 writer_tasks[i]); 1041 if (torture_init_error(firsterr)) 1042 goto unwind; 1043 } 1044 torture_init_end(); 1045 return 0; 1046 1047 unwind: 1048 torture_init_end(); 1049 rcu_scale_cleanup(); 1050 if (shutdown) { 1051 WARN_ON(!IS_MODULE(CONFIG_RCU_SCALE_TEST)); 1052 kernel_power_off(); 1053 } 1054 return firsterr; 1055 } 1056 1057 module_init(rcu_scale_init); 1058 module_exit(rcu_scale_cleanup); 1059