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TOMOYO Linux Cross Reference
Linux/kernel/rcu/rcuperf.c

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  1 /*
  2  * Read-Copy Update module-based performance-test facility
  3  *
  4  * This program is free software; you can redistribute it and/or modify
  5  * it under the terms of the GNU General Public License as published by
  6  * the Free Software Foundation; either version 2 of the License, or
  7  * (at your option) any later version.
  8  *
  9  * This program is distributed in the hope that it will be useful,
 10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12  * GNU General Public License for more details.
 13  *
 14  * You should have received a copy of the GNU General Public License
 15  * along with this program; if not, you can access it online at
 16  * http://www.gnu.org/licenses/gpl-2.0.html.
 17  *
 18  * Copyright (C) IBM Corporation, 2015
 19  *
 20  * Authors: Paul E. McKenney <paulmck@us.ibm.com>
 21  */
 22 #include <linux/types.h>
 23 #include <linux/kernel.h>
 24 #include <linux/init.h>
 25 #include <linux/module.h>
 26 #include <linux/kthread.h>
 27 #include <linux/err.h>
 28 #include <linux/spinlock.h>
 29 #include <linux/smp.h>
 30 #include <linux/rcupdate.h>
 31 #include <linux/interrupt.h>
 32 #include <linux/sched.h>
 33 #include <uapi/linux/sched/types.h>
 34 #include <linux/atomic.h>
 35 #include <linux/bitops.h>
 36 #include <linux/completion.h>
 37 #include <linux/moduleparam.h>
 38 #include <linux/percpu.h>
 39 #include <linux/notifier.h>
 40 #include <linux/reboot.h>
 41 #include <linux/freezer.h>
 42 #include <linux/cpu.h>
 43 #include <linux/delay.h>
 44 #include <linux/stat.h>
 45 #include <linux/srcu.h>
 46 #include <linux/slab.h>
 47 #include <asm/byteorder.h>
 48 #include <linux/torture.h>
 49 #include <linux/vmalloc.h>
 50 
 51 #include "rcu.h"
 52 
 53 MODULE_LICENSE("GPL");
 54 MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.vnet.ibm.com>");
 55 
 56 #define PERF_FLAG "-perf:"
 57 #define PERFOUT_STRING(s) \
 58         pr_alert("%s" PERF_FLAG " %s\n", perf_type, s)
 59 #define VERBOSE_PERFOUT_STRING(s) \
 60         do { if (verbose) pr_alert("%s" PERF_FLAG " %s\n", perf_type, s); } while (0)
 61 #define VERBOSE_PERFOUT_ERRSTRING(s) \
 62         do { if (verbose) pr_alert("%s" PERF_FLAG "!!! %s\n", perf_type, s); } while (0)
 63 
 64 torture_param(bool, gp_async, false, "Use asynchronous GP wait primitives");
 65 torture_param(int, gp_async_max, 1000, "Max # outstanding waits per reader");
 66 torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
 67 torture_param(int, holdoff, 10, "Holdoff time before test start (s)");
 68 torture_param(int, nreaders, 0, "Number of RCU reader threads");
 69 torture_param(int, nwriters, -1, "Number of RCU updater threads");
 70 torture_param(bool, shutdown, !IS_ENABLED(MODULE),
 71               "Shutdown at end of performance tests.");
 72 torture_param(bool, verbose, true, "Enable verbose debugging printk()s");
 73 torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable");
 74 
 75 static char *perf_type = "rcu";
 76 module_param(perf_type, charp, 0444);
 77 MODULE_PARM_DESC(perf_type, "Type of RCU to performance-test (rcu, rcu_bh, ...)");
 78 
 79 static int nrealreaders;
 80 static int nrealwriters;
 81 static struct task_struct **writer_tasks;
 82 static struct task_struct **reader_tasks;
 83 static struct task_struct *shutdown_task;
 84 
 85 static u64 **writer_durations;
 86 static int *writer_n_durations;
 87 static atomic_t n_rcu_perf_reader_started;
 88 static atomic_t n_rcu_perf_writer_started;
 89 static atomic_t n_rcu_perf_writer_finished;
 90 static wait_queue_head_t shutdown_wq;
 91 static u64 t_rcu_perf_writer_started;
 92 static u64 t_rcu_perf_writer_finished;
 93 static unsigned long b_rcu_perf_writer_started;
 94 static unsigned long b_rcu_perf_writer_finished;
 95 static DEFINE_PER_CPU(atomic_t, n_async_inflight);
 96 
 97 static int rcu_perf_writer_state;
 98 #define RTWS_INIT               0
 99 #define RTWS_ASYNC              1
100 #define RTWS_BARRIER            2
101 #define RTWS_EXP_SYNC           3
102 #define RTWS_SYNC               4
103 #define RTWS_IDLE               5
104 #define RTWS_STOPPING           6
105 
106 #define MAX_MEAS 10000
107 #define MIN_MEAS 100
108 
109 static int perf_runnable = IS_ENABLED(MODULE);
110 module_param(perf_runnable, int, 0444);
111 MODULE_PARM_DESC(perf_runnable, "Start rcuperf at boot");
112 
113 /*
114  * Operations vector for selecting different types of tests.
115  */
116 
117 struct rcu_perf_ops {
118         int ptype;
119         void (*init)(void);
120         void (*cleanup)(void);
121         int (*readlock)(void);
122         void (*readunlock)(int idx);
123         unsigned long (*started)(void);
124         unsigned long (*completed)(void);
125         unsigned long (*exp_completed)(void);
126         void (*async)(struct rcu_head *head, rcu_callback_t func);
127         void (*gp_barrier)(void);
128         void (*sync)(void);
129         void (*exp_sync)(void);
130         const char *name;
131 };
132 
133 static struct rcu_perf_ops *cur_ops;
134 
135 /*
136  * Definitions for rcu perf testing.
137  */
138 
139 static int rcu_perf_read_lock(void) __acquires(RCU)
140 {
141         rcu_read_lock();
142         return 0;
143 }
144 
145 static void rcu_perf_read_unlock(int idx) __releases(RCU)
146 {
147         rcu_read_unlock();
148 }
149 
150 static unsigned long __maybe_unused rcu_no_completed(void)
151 {
152         return 0;
153 }
154 
155 static void rcu_sync_perf_init(void)
156 {
157 }
158 
159 static struct rcu_perf_ops rcu_ops = {
160         .ptype          = RCU_FLAVOR,
161         .init           = rcu_sync_perf_init,
162         .readlock       = rcu_perf_read_lock,
163         .readunlock     = rcu_perf_read_unlock,
164         .started        = rcu_batches_started,
165         .completed      = rcu_batches_completed,
166         .exp_completed  = rcu_exp_batches_completed,
167         .async          = call_rcu,
168         .gp_barrier     = rcu_barrier,
169         .sync           = synchronize_rcu,
170         .exp_sync       = synchronize_rcu_expedited,
171         .name           = "rcu"
172 };
173 
174 /*
175  * Definitions for rcu_bh perf testing.
176  */
177 
178 static int rcu_bh_perf_read_lock(void) __acquires(RCU_BH)
179 {
180         rcu_read_lock_bh();
181         return 0;
182 }
183 
184 static void rcu_bh_perf_read_unlock(int idx) __releases(RCU_BH)
185 {
186         rcu_read_unlock_bh();
187 }
188 
189 static struct rcu_perf_ops rcu_bh_ops = {
190         .ptype          = RCU_BH_FLAVOR,
191         .init           = rcu_sync_perf_init,
192         .readlock       = rcu_bh_perf_read_lock,
193         .readunlock     = rcu_bh_perf_read_unlock,
194         .started        = rcu_batches_started_bh,
195         .completed      = rcu_batches_completed_bh,
196         .exp_completed  = rcu_exp_batches_completed_sched,
197         .async          = call_rcu_bh,
198         .gp_barrier     = rcu_barrier_bh,
199         .sync           = synchronize_rcu_bh,
200         .exp_sync       = synchronize_rcu_bh_expedited,
201         .name           = "rcu_bh"
202 };
203 
204 /*
205  * Definitions for srcu perf testing.
206  */
207 
208 DEFINE_STATIC_SRCU(srcu_ctl_perf);
209 static struct srcu_struct *srcu_ctlp = &srcu_ctl_perf;
210 
211 static int srcu_perf_read_lock(void) __acquires(srcu_ctlp)
212 {
213         return srcu_read_lock(srcu_ctlp);
214 }
215 
216 static void srcu_perf_read_unlock(int idx) __releases(srcu_ctlp)
217 {
218         srcu_read_unlock(srcu_ctlp, idx);
219 }
220 
221 static unsigned long srcu_perf_completed(void)
222 {
223         return srcu_batches_completed(srcu_ctlp);
224 }
225 
226 static void srcu_call_rcu(struct rcu_head *head, rcu_callback_t func)
227 {
228         call_srcu(srcu_ctlp, head, func);
229 }
230 
231 static void srcu_rcu_barrier(void)
232 {
233         srcu_barrier(srcu_ctlp);
234 }
235 
236 static void srcu_perf_synchronize(void)
237 {
238         synchronize_srcu(srcu_ctlp);
239 }
240 
241 static void srcu_perf_synchronize_expedited(void)
242 {
243         synchronize_srcu_expedited(srcu_ctlp);
244 }
245 
246 static struct rcu_perf_ops srcu_ops = {
247         .ptype          = SRCU_FLAVOR,
248         .init           = rcu_sync_perf_init,
249         .readlock       = srcu_perf_read_lock,
250         .readunlock     = srcu_perf_read_unlock,
251         .started        = NULL,
252         .completed      = srcu_perf_completed,
253         .exp_completed  = srcu_perf_completed,
254         .async          = srcu_call_rcu,
255         .gp_barrier     = srcu_rcu_barrier,
256         .sync           = srcu_perf_synchronize,
257         .exp_sync       = srcu_perf_synchronize_expedited,
258         .name           = "srcu"
259 };
260 
261 static struct srcu_struct srcud;
262 
263 static void srcu_sync_perf_init(void)
264 {
265         srcu_ctlp = &srcud;
266         init_srcu_struct(srcu_ctlp);
267 }
268 
269 static void srcu_sync_perf_cleanup(void)
270 {
271         cleanup_srcu_struct(srcu_ctlp);
272 }
273 
274 static struct rcu_perf_ops srcud_ops = {
275         .ptype          = SRCU_FLAVOR,
276         .init           = srcu_sync_perf_init,
277         .cleanup        = srcu_sync_perf_cleanup,
278         .readlock       = srcu_perf_read_lock,
279         .readunlock     = srcu_perf_read_unlock,
280         .started        = NULL,
281         .completed      = srcu_perf_completed,
282         .exp_completed  = srcu_perf_completed,
283         .async          = srcu_call_rcu,
284         .gp_barrier     = srcu_rcu_barrier,
285         .sync           = srcu_perf_synchronize,
286         .exp_sync       = srcu_perf_synchronize_expedited,
287         .name           = "srcud"
288 };
289 
290 /*
291  * Definitions for sched perf testing.
292  */
293 
294 static int sched_perf_read_lock(void)
295 {
296         preempt_disable();
297         return 0;
298 }
299 
300 static void sched_perf_read_unlock(int idx)
301 {
302         preempt_enable();
303 }
304 
305 static struct rcu_perf_ops sched_ops = {
306         .ptype          = RCU_SCHED_FLAVOR,
307         .init           = rcu_sync_perf_init,
308         .readlock       = sched_perf_read_lock,
309         .readunlock     = sched_perf_read_unlock,
310         .started        = rcu_batches_started_sched,
311         .completed      = rcu_batches_completed_sched,
312         .exp_completed  = rcu_exp_batches_completed_sched,
313         .async          = call_rcu_sched,
314         .gp_barrier     = rcu_barrier_sched,
315         .sync           = synchronize_sched,
316         .exp_sync       = synchronize_sched_expedited,
317         .name           = "sched"
318 };
319 
320 /*
321  * Definitions for RCU-tasks perf testing.
322  */
323 
324 static int tasks_perf_read_lock(void)
325 {
326         return 0;
327 }
328 
329 static void tasks_perf_read_unlock(int idx)
330 {
331 }
332 
333 static struct rcu_perf_ops tasks_ops = {
334         .ptype          = RCU_TASKS_FLAVOR,
335         .init           = rcu_sync_perf_init,
336         .readlock       = tasks_perf_read_lock,
337         .readunlock     = tasks_perf_read_unlock,
338         .started        = rcu_no_completed,
339         .completed      = rcu_no_completed,
340         .async          = call_rcu_tasks,
341         .gp_barrier     = rcu_barrier_tasks,
342         .sync           = synchronize_rcu_tasks,
343         .exp_sync       = synchronize_rcu_tasks,
344         .name           = "tasks"
345 };
346 
347 static bool __maybe_unused torturing_tasks(void)
348 {
349         return cur_ops == &tasks_ops;
350 }
351 
352 /*
353  * If performance tests complete, wait for shutdown to commence.
354  */
355 static void rcu_perf_wait_shutdown(void)
356 {
357         cond_resched_rcu_qs();
358         if (atomic_read(&n_rcu_perf_writer_finished) < nrealwriters)
359                 return;
360         while (!torture_must_stop())
361                 schedule_timeout_uninterruptible(1);
362 }
363 
364 /*
365  * RCU perf reader kthread.  Repeatedly does empty RCU read-side
366  * critical section, minimizing update-side interference.
367  */
368 static int
369 rcu_perf_reader(void *arg)
370 {
371         unsigned long flags;
372         int idx;
373         long me = (long)arg;
374 
375         VERBOSE_PERFOUT_STRING("rcu_perf_reader task started");
376         set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
377         set_user_nice(current, MAX_NICE);
378         atomic_inc(&n_rcu_perf_reader_started);
379 
380         do {
381                 local_irq_save(flags);
382                 idx = cur_ops->readlock();
383                 cur_ops->readunlock(idx);
384                 local_irq_restore(flags);
385                 rcu_perf_wait_shutdown();
386         } while (!torture_must_stop());
387         torture_kthread_stopping("rcu_perf_reader");
388         return 0;
389 }
390 
391 /*
392  * Callback function for asynchronous grace periods from rcu_perf_writer().
393  */
394 static void rcu_perf_async_cb(struct rcu_head *rhp)
395 {
396         atomic_dec(this_cpu_ptr(&n_async_inflight));
397         kfree(rhp);
398 }
399 
400 /*
401  * RCU perf writer kthread.  Repeatedly does a grace period.
402  */
403 static int
404 rcu_perf_writer(void *arg)
405 {
406         int i = 0;
407         int i_max;
408         long me = (long)arg;
409         struct rcu_head *rhp = NULL;
410         struct sched_param sp;
411         bool started = false, done = false, alldone = false;
412         u64 t;
413         u64 *wdp;
414         u64 *wdpp = writer_durations[me];
415 
416         VERBOSE_PERFOUT_STRING("rcu_perf_writer task started");
417         WARN_ON(!wdpp);
418         set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
419         sp.sched_priority = 1;
420         sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
421 
422         if (holdoff)
423                 schedule_timeout_uninterruptible(holdoff * HZ);
424 
425         t = ktime_get_mono_fast_ns();
426         if (atomic_inc_return(&n_rcu_perf_writer_started) >= nrealwriters) {
427                 t_rcu_perf_writer_started = t;
428                 if (gp_exp) {
429                         b_rcu_perf_writer_started =
430                                 cur_ops->exp_completed() / 2;
431                 } else {
432                         b_rcu_perf_writer_started =
433                                 cur_ops->completed();
434                 }
435         }
436 
437         do {
438                 if (writer_holdoff)
439                         udelay(writer_holdoff);
440                 wdp = &wdpp[i];
441                 *wdp = ktime_get_mono_fast_ns();
442                 if (gp_async) {
443 retry:
444                         if (!rhp)
445                                 rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
446                         if (rhp && atomic_read(this_cpu_ptr(&n_async_inflight)) < gp_async_max) {
447                                 rcu_perf_writer_state = RTWS_ASYNC;
448                                 atomic_inc(this_cpu_ptr(&n_async_inflight));
449                                 cur_ops->async(rhp, rcu_perf_async_cb);
450                                 rhp = NULL;
451                         } else if (!kthread_should_stop()) {
452                                 rcu_perf_writer_state = RTWS_BARRIER;
453                                 cur_ops->gp_barrier();
454                                 goto retry;
455                         } else {
456                                 kfree(rhp); /* Because we are stopping. */
457                         }
458                 } else if (gp_exp) {
459                         rcu_perf_writer_state = RTWS_EXP_SYNC;
460                         cur_ops->exp_sync();
461                 } else {
462                         rcu_perf_writer_state = RTWS_SYNC;
463                         cur_ops->sync();
464                 }
465                 rcu_perf_writer_state = RTWS_IDLE;
466                 t = ktime_get_mono_fast_ns();
467                 *wdp = t - *wdp;
468                 i_max = i;
469                 if (!started &&
470                     atomic_read(&n_rcu_perf_writer_started) >= nrealwriters)
471                         started = true;
472                 if (!done && i >= MIN_MEAS) {
473                         done = true;
474                         sp.sched_priority = 0;
475                         sched_setscheduler_nocheck(current,
476                                                    SCHED_NORMAL, &sp);
477                         pr_alert("%s%s rcu_perf_writer %ld has %d measurements\n",
478                                  perf_type, PERF_FLAG, me, MIN_MEAS);
479                         if (atomic_inc_return(&n_rcu_perf_writer_finished) >=
480                             nrealwriters) {
481                                 schedule_timeout_interruptible(10);
482                                 rcu_ftrace_dump(DUMP_ALL);
483                                 PERFOUT_STRING("Test complete");
484                                 t_rcu_perf_writer_finished = t;
485                                 if (gp_exp) {
486                                         b_rcu_perf_writer_finished =
487                                                 cur_ops->exp_completed() / 2;
488                                 } else {
489                                         b_rcu_perf_writer_finished =
490                                                 cur_ops->completed();
491                                 }
492                                 if (shutdown) {
493                                         smp_mb(); /* Assign before wake. */
494                                         wake_up(&shutdown_wq);
495                                 }
496                         }
497                 }
498                 if (done && !alldone &&
499                     atomic_read(&n_rcu_perf_writer_finished) >= nrealwriters)
500                         alldone = true;
501                 if (started && !alldone && i < MAX_MEAS - 1)
502                         i++;
503                 rcu_perf_wait_shutdown();
504         } while (!torture_must_stop());
505         if (gp_async) {
506                 rcu_perf_writer_state = RTWS_BARRIER;
507                 cur_ops->gp_barrier();
508         }
509         rcu_perf_writer_state = RTWS_STOPPING;
510         writer_n_durations[me] = i_max;
511         torture_kthread_stopping("rcu_perf_writer");
512         return 0;
513 }
514 
515 static inline void
516 rcu_perf_print_module_parms(struct rcu_perf_ops *cur_ops, const char *tag)
517 {
518         pr_alert("%s" PERF_FLAG
519                  "--- %s: nreaders=%d nwriters=%d verbose=%d shutdown=%d\n",
520                  perf_type, tag, nrealreaders, nrealwriters, verbose, shutdown);
521 }
522 
523 static void
524 rcu_perf_cleanup(void)
525 {
526         int i;
527         int j;
528         int ngps = 0;
529         u64 *wdp;
530         u64 *wdpp;
531 
532         /*
533          * Would like warning at start, but everything is expedited
534          * during the mid-boot phase, so have to wait till the end.
535          */
536         if (rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp)
537                 VERBOSE_PERFOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!");
538         if (rcu_gp_is_normal() && gp_exp)
539                 VERBOSE_PERFOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!");
540         if (gp_exp && gp_async)
541                 VERBOSE_PERFOUT_ERRSTRING("No expedited async GPs, so went with async!");
542 
543         if (torture_cleanup_begin())
544                 return;
545 
546         if (reader_tasks) {
547                 for (i = 0; i < nrealreaders; i++)
548                         torture_stop_kthread(rcu_perf_reader,
549                                              reader_tasks[i]);
550                 kfree(reader_tasks);
551         }
552 
553         if (writer_tasks) {
554                 for (i = 0; i < nrealwriters; i++) {
555                         torture_stop_kthread(rcu_perf_writer,
556                                              writer_tasks[i]);
557                         if (!writer_n_durations)
558                                 continue;
559                         j = writer_n_durations[i];
560                         pr_alert("%s%s writer %d gps: %d\n",
561                                  perf_type, PERF_FLAG, i, j);
562                         ngps += j;
563                 }
564                 pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n",
565                          perf_type, PERF_FLAG,
566                          t_rcu_perf_writer_started, t_rcu_perf_writer_finished,
567                          t_rcu_perf_writer_finished -
568                          t_rcu_perf_writer_started,
569                          ngps,
570                          b_rcu_perf_writer_finished -
571                          b_rcu_perf_writer_started);
572                 for (i = 0; i < nrealwriters; i++) {
573                         if (!writer_durations)
574                                 break;
575                         if (!writer_n_durations)
576                                 continue;
577                         wdpp = writer_durations[i];
578                         if (!wdpp)
579                                 continue;
580                         for (j = 0; j <= writer_n_durations[i]; j++) {
581                                 wdp = &wdpp[j];
582                                 pr_alert("%s%s %4d writer-duration: %5d %llu\n",
583                                         perf_type, PERF_FLAG,
584                                         i, j, *wdp);
585                                 if (j % 100 == 0)
586                                         schedule_timeout_uninterruptible(1);
587                         }
588                         kfree(writer_durations[i]);
589                 }
590                 kfree(writer_tasks);
591                 kfree(writer_durations);
592                 kfree(writer_n_durations);
593         }
594 
595         /* Do flavor-specific cleanup operations.  */
596         if (cur_ops->cleanup != NULL)
597                 cur_ops->cleanup();
598 
599         torture_cleanup_end();
600 }
601 
602 /*
603  * Return the number if non-negative.  If -1, the number of CPUs.
604  * If less than -1, that much less than the number of CPUs, but
605  * at least one.
606  */
607 static int compute_real(int n)
608 {
609         int nr;
610 
611         if (n >= 0) {
612                 nr = n;
613         } else {
614                 nr = num_online_cpus() + 1 + n;
615                 if (nr <= 0)
616                         nr = 1;
617         }
618         return nr;
619 }
620 
621 /*
622  * RCU perf shutdown kthread.  Just waits to be awakened, then shuts
623  * down system.
624  */
625 static int
626 rcu_perf_shutdown(void *arg)
627 {
628         do {
629                 wait_event(shutdown_wq,
630                            atomic_read(&n_rcu_perf_writer_finished) >=
631                            nrealwriters);
632         } while (atomic_read(&n_rcu_perf_writer_finished) < nrealwriters);
633         smp_mb(); /* Wake before output. */
634         rcu_perf_cleanup();
635         kernel_power_off();
636         return -EINVAL;
637 }
638 
639 static int __init
640 rcu_perf_init(void)
641 {
642         long i;
643         int firsterr = 0;
644         static struct rcu_perf_ops *perf_ops[] = {
645                 &rcu_ops, &rcu_bh_ops, &srcu_ops, &srcud_ops, &sched_ops,
646                 &tasks_ops,
647         };
648 
649         if (!torture_init_begin(perf_type, verbose, &perf_runnable))
650                 return -EBUSY;
651 
652         /* Process args and tell the world that the perf'er is on the job. */
653         for (i = 0; i < ARRAY_SIZE(perf_ops); i++) {
654                 cur_ops = perf_ops[i];
655                 if (strcmp(perf_type, cur_ops->name) == 0)
656                         break;
657         }
658         if (i == ARRAY_SIZE(perf_ops)) {
659                 pr_alert("rcu-perf: invalid perf type: \"%s\"\n",
660                          perf_type);
661                 pr_alert("rcu-perf types:");
662                 for (i = 0; i < ARRAY_SIZE(perf_ops); i++)
663                         pr_alert(" %s", perf_ops[i]->name);
664                 pr_alert("\n");
665                 firsterr = -EINVAL;
666                 goto unwind;
667         }
668         if (cur_ops->init)
669                 cur_ops->init();
670 
671         nrealwriters = compute_real(nwriters);
672         nrealreaders = compute_real(nreaders);
673         atomic_set(&n_rcu_perf_reader_started, 0);
674         atomic_set(&n_rcu_perf_writer_started, 0);
675         atomic_set(&n_rcu_perf_writer_finished, 0);
676         rcu_perf_print_module_parms(cur_ops, "Start of test");
677 
678         /* Start up the kthreads. */
679 
680         if (shutdown) {
681                 init_waitqueue_head(&shutdown_wq);
682                 firsterr = torture_create_kthread(rcu_perf_shutdown, NULL,
683                                                   shutdown_task);
684                 if (firsterr)
685                         goto unwind;
686                 schedule_timeout_uninterruptible(1);
687         }
688         reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
689                                GFP_KERNEL);
690         if (reader_tasks == NULL) {
691                 VERBOSE_PERFOUT_ERRSTRING("out of memory");
692                 firsterr = -ENOMEM;
693                 goto unwind;
694         }
695         for (i = 0; i < nrealreaders; i++) {
696                 firsterr = torture_create_kthread(rcu_perf_reader, (void *)i,
697                                                   reader_tasks[i]);
698                 if (firsterr)
699                         goto unwind;
700         }
701         while (atomic_read(&n_rcu_perf_reader_started) < nrealreaders)
702                 schedule_timeout_uninterruptible(1);
703         writer_tasks = kcalloc(nrealwriters, sizeof(reader_tasks[0]),
704                                GFP_KERNEL);
705         writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations),
706                                    GFP_KERNEL);
707         writer_n_durations =
708                 kcalloc(nrealwriters, sizeof(*writer_n_durations),
709                         GFP_KERNEL);
710         if (!writer_tasks || !writer_durations || !writer_n_durations) {
711                 VERBOSE_PERFOUT_ERRSTRING("out of memory");
712                 firsterr = -ENOMEM;
713                 goto unwind;
714         }
715         for (i = 0; i < nrealwriters; i++) {
716                 writer_durations[i] =
717                         kcalloc(MAX_MEAS, sizeof(*writer_durations[i]),
718                                 GFP_KERNEL);
719                 if (!writer_durations[i]) {
720                         firsterr = -ENOMEM;
721                         goto unwind;
722                 }
723                 firsterr = torture_create_kthread(rcu_perf_writer, (void *)i,
724                                                   writer_tasks[i]);
725                 if (firsterr)
726                         goto unwind;
727         }
728         torture_init_end();
729         return 0;
730 
731 unwind:
732         torture_init_end();
733         rcu_perf_cleanup();
734         return firsterr;
735 }
736 
737 module_init(rcu_perf_init);
738 module_exit(rcu_perf_cleanup);
739 

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