netfilter: complete the deprecation of CONFIG_NF_CT_ACCT
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / rcutorture.c
blob6535ac8bc6a5935ceebd05ea24390e25b13fba41
1 /*
2 * Read-Copy Update module-based torture test facility
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.
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.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 * Copyright (C) IBM Corporation, 2005, 2006
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Josh Triplett <josh@freedesktop.org>
23 * See also: Documentation/RCU/torture.txt
25 #include <linux/types.h>
26 #include <linux/kernel.h>
27 #include <linux/init.h>
28 #include <linux/module.h>
29 #include <linux/kthread.h>
30 #include <linux/err.h>
31 #include <linux/spinlock.h>
32 #include <linux/smp.h>
33 #include <linux/rcupdate.h>
34 #include <linux/interrupt.h>
35 #include <linux/sched.h>
36 #include <asm/atomic.h>
37 #include <linux/bitops.h>
38 #include <linux/completion.h>
39 #include <linux/moduleparam.h>
40 #include <linux/percpu.h>
41 #include <linux/notifier.h>
42 #include <linux/reboot.h>
43 #include <linux/freezer.h>
44 #include <linux/cpu.h>
45 #include <linux/delay.h>
46 #include <linux/stat.h>
47 #include <linux/srcu.h>
48 #include <linux/slab.h>
49 #include <asm/byteorder.h>
51 MODULE_LICENSE("GPL");
52 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and "
53 "Josh Triplett <josh@freedesktop.org>");
55 static int nreaders = -1; /* # reader threads, defaults to 2*ncpus */
56 static int nfakewriters = 4; /* # fake writer threads */
57 static int stat_interval; /* Interval between stats, in seconds. */
58 /* Defaults to "only at end of test". */
59 static int verbose; /* Print more debug info. */
60 static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */
61 static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/
62 static int stutter = 5; /* Start/stop testing interval (in sec) */
63 static int irqreader = 1; /* RCU readers from irq (timers). */
64 static int fqs_duration = 0; /* Duration of bursts (us), 0 to disable. */
65 static int fqs_holdoff = 0; /* Hold time within burst (us). */
66 static int fqs_stutter = 3; /* Wait time between bursts (s). */
67 static char *torture_type = "rcu"; /* What RCU implementation to torture. */
69 module_param(nreaders, int, 0444);
70 MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
71 module_param(nfakewriters, int, 0444);
72 MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
73 module_param(stat_interval, int, 0444);
74 MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
75 module_param(verbose, bool, 0444);
76 MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
77 module_param(test_no_idle_hz, bool, 0444);
78 MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
79 module_param(shuffle_interval, int, 0444);
80 MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
81 module_param(stutter, int, 0444);
82 MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
83 module_param(irqreader, int, 0444);
84 MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
85 module_param(fqs_duration, int, 0444);
86 MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us)");
87 module_param(fqs_holdoff, int, 0444);
88 MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)");
89 module_param(fqs_stutter, int, 0444);
90 MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
91 module_param(torture_type, charp, 0444);
92 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
94 #define TORTURE_FLAG "-torture:"
95 #define PRINTK_STRING(s) \
96 do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
97 #define VERBOSE_PRINTK_STRING(s) \
98 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
99 #define VERBOSE_PRINTK_ERRSTRING(s) \
100 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
102 static char printk_buf[4096];
104 static int nrealreaders;
105 static struct task_struct *writer_task;
106 static struct task_struct **fakewriter_tasks;
107 static struct task_struct **reader_tasks;
108 static struct task_struct *stats_task;
109 static struct task_struct *shuffler_task;
110 static struct task_struct *stutter_task;
111 static struct task_struct *fqs_task;
113 #define RCU_TORTURE_PIPE_LEN 10
115 struct rcu_torture {
116 struct rcu_head rtort_rcu;
117 int rtort_pipe_count;
118 struct list_head rtort_free;
119 int rtort_mbtest;
122 static LIST_HEAD(rcu_torture_freelist);
123 static struct rcu_torture *rcu_torture_current;
124 static long rcu_torture_current_version;
125 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
126 static DEFINE_SPINLOCK(rcu_torture_lock);
127 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
128 { 0 };
129 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
130 { 0 };
131 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
132 static atomic_t n_rcu_torture_alloc;
133 static atomic_t n_rcu_torture_alloc_fail;
134 static atomic_t n_rcu_torture_free;
135 static atomic_t n_rcu_torture_mberror;
136 static atomic_t n_rcu_torture_error;
137 static long n_rcu_torture_timers;
138 static struct list_head rcu_torture_removed;
139 static cpumask_var_t shuffle_tmp_mask;
141 static int stutter_pause_test;
143 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
144 #define RCUTORTURE_RUNNABLE_INIT 1
145 #else
146 #define RCUTORTURE_RUNNABLE_INIT 0
147 #endif
148 int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
150 /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
152 #define FULLSTOP_DONTSTOP 0 /* Normal operation. */
153 #define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */
154 #define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */
155 static int fullstop = FULLSTOP_RMMOD;
156 DEFINE_MUTEX(fullstop_mutex); /* Protect fullstop transitions and spawning */
157 /* of kthreads. */
160 * Detect and respond to a system shutdown.
162 static int
163 rcutorture_shutdown_notify(struct notifier_block *unused1,
164 unsigned long unused2, void *unused3)
166 mutex_lock(&fullstop_mutex);
167 if (fullstop == FULLSTOP_DONTSTOP)
168 fullstop = FULLSTOP_SHUTDOWN;
169 else
170 printk(KERN_WARNING /* but going down anyway, so... */
171 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
172 mutex_unlock(&fullstop_mutex);
173 return NOTIFY_DONE;
177 * Absorb kthreads into a kernel function that won't return, so that
178 * they won't ever access module text or data again.
180 static void rcutorture_shutdown_absorb(char *title)
182 if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
183 printk(KERN_NOTICE
184 "rcutorture thread %s parking due to system shutdown\n",
185 title);
186 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
191 * Allocate an element from the rcu_tortures pool.
193 static struct rcu_torture *
194 rcu_torture_alloc(void)
196 struct list_head *p;
198 spin_lock_bh(&rcu_torture_lock);
199 if (list_empty(&rcu_torture_freelist)) {
200 atomic_inc(&n_rcu_torture_alloc_fail);
201 spin_unlock_bh(&rcu_torture_lock);
202 return NULL;
204 atomic_inc(&n_rcu_torture_alloc);
205 p = rcu_torture_freelist.next;
206 list_del_init(p);
207 spin_unlock_bh(&rcu_torture_lock);
208 return container_of(p, struct rcu_torture, rtort_free);
212 * Free an element to the rcu_tortures pool.
214 static void
215 rcu_torture_free(struct rcu_torture *p)
217 atomic_inc(&n_rcu_torture_free);
218 spin_lock_bh(&rcu_torture_lock);
219 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
220 spin_unlock_bh(&rcu_torture_lock);
223 struct rcu_random_state {
224 unsigned long rrs_state;
225 long rrs_count;
228 #define RCU_RANDOM_MULT 39916801 /* prime */
229 #define RCU_RANDOM_ADD 479001701 /* prime */
230 #define RCU_RANDOM_REFRESH 10000
232 #define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
235 * Crude but fast random-number generator. Uses a linear congruential
236 * generator, with occasional help from cpu_clock().
238 static unsigned long
239 rcu_random(struct rcu_random_state *rrsp)
241 if (--rrsp->rrs_count < 0) {
242 rrsp->rrs_state +=
243 (unsigned long)cpu_clock(raw_smp_processor_id());
244 rrsp->rrs_count = RCU_RANDOM_REFRESH;
246 rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
247 return swahw32(rrsp->rrs_state);
250 static void
251 rcu_stutter_wait(char *title)
253 while (stutter_pause_test || !rcutorture_runnable) {
254 if (rcutorture_runnable)
255 schedule_timeout_interruptible(1);
256 else
257 schedule_timeout_interruptible(round_jiffies_relative(HZ));
258 rcutorture_shutdown_absorb(title);
263 * Operations vector for selecting different types of tests.
266 struct rcu_torture_ops {
267 void (*init)(void);
268 void (*cleanup)(void);
269 int (*readlock)(void);
270 void (*read_delay)(struct rcu_random_state *rrsp);
271 void (*readunlock)(int idx);
272 int (*completed)(void);
273 void (*deferred_free)(struct rcu_torture *p);
274 void (*sync)(void);
275 void (*cb_barrier)(void);
276 void (*fqs)(void);
277 int (*stats)(char *page);
278 int irq_capable;
279 char *name;
282 static struct rcu_torture_ops *cur_ops;
285 * Definitions for rcu torture testing.
288 static int rcu_torture_read_lock(void) __acquires(RCU)
290 rcu_read_lock();
291 return 0;
294 static void rcu_read_delay(struct rcu_random_state *rrsp)
296 const unsigned long shortdelay_us = 200;
297 const unsigned long longdelay_ms = 50;
299 /* We want a short delay sometimes to make a reader delay the grace
300 * period, and we want a long delay occasionally to trigger
301 * force_quiescent_state. */
303 if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
304 mdelay(longdelay_ms);
305 if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
306 udelay(shortdelay_us);
309 static void rcu_torture_read_unlock(int idx) __releases(RCU)
311 rcu_read_unlock();
314 static int rcu_torture_completed(void)
316 return rcu_batches_completed();
319 static void
320 rcu_torture_cb(struct rcu_head *p)
322 int i;
323 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
325 if (fullstop != FULLSTOP_DONTSTOP) {
326 /* Test is ending, just drop callbacks on the floor. */
327 /* The next initialization will pick up the pieces. */
328 return;
330 i = rp->rtort_pipe_count;
331 if (i > RCU_TORTURE_PIPE_LEN)
332 i = RCU_TORTURE_PIPE_LEN;
333 atomic_inc(&rcu_torture_wcount[i]);
334 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
335 rp->rtort_mbtest = 0;
336 rcu_torture_free(rp);
337 } else
338 cur_ops->deferred_free(rp);
341 static int rcu_no_completed(void)
343 return 0;
346 static void rcu_torture_deferred_free(struct rcu_torture *p)
348 call_rcu(&p->rtort_rcu, rcu_torture_cb);
351 static struct rcu_torture_ops rcu_ops = {
352 .init = NULL,
353 .cleanup = NULL,
354 .readlock = rcu_torture_read_lock,
355 .read_delay = rcu_read_delay,
356 .readunlock = rcu_torture_read_unlock,
357 .completed = rcu_torture_completed,
358 .deferred_free = rcu_torture_deferred_free,
359 .sync = synchronize_rcu,
360 .cb_barrier = rcu_barrier,
361 .fqs = rcu_force_quiescent_state,
362 .stats = NULL,
363 .irq_capable = 1,
364 .name = "rcu"
367 static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
369 int i;
370 struct rcu_torture *rp;
371 struct rcu_torture *rp1;
373 cur_ops->sync();
374 list_add(&p->rtort_free, &rcu_torture_removed);
375 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
376 i = rp->rtort_pipe_count;
377 if (i > RCU_TORTURE_PIPE_LEN)
378 i = RCU_TORTURE_PIPE_LEN;
379 atomic_inc(&rcu_torture_wcount[i]);
380 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
381 rp->rtort_mbtest = 0;
382 list_del(&rp->rtort_free);
383 rcu_torture_free(rp);
388 static void rcu_sync_torture_init(void)
390 INIT_LIST_HEAD(&rcu_torture_removed);
393 static struct rcu_torture_ops rcu_sync_ops = {
394 .init = rcu_sync_torture_init,
395 .cleanup = NULL,
396 .readlock = rcu_torture_read_lock,
397 .read_delay = rcu_read_delay,
398 .readunlock = rcu_torture_read_unlock,
399 .completed = rcu_torture_completed,
400 .deferred_free = rcu_sync_torture_deferred_free,
401 .sync = synchronize_rcu,
402 .cb_barrier = NULL,
403 .fqs = rcu_force_quiescent_state,
404 .stats = NULL,
405 .irq_capable = 1,
406 .name = "rcu_sync"
409 static struct rcu_torture_ops rcu_expedited_ops = {
410 .init = rcu_sync_torture_init,
411 .cleanup = NULL,
412 .readlock = rcu_torture_read_lock,
413 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
414 .readunlock = rcu_torture_read_unlock,
415 .completed = rcu_no_completed,
416 .deferred_free = rcu_sync_torture_deferred_free,
417 .sync = synchronize_rcu_expedited,
418 .cb_barrier = NULL,
419 .fqs = rcu_force_quiescent_state,
420 .stats = NULL,
421 .irq_capable = 1,
422 .name = "rcu_expedited"
426 * Definitions for rcu_bh torture testing.
429 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
431 rcu_read_lock_bh();
432 return 0;
435 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
437 rcu_read_unlock_bh();
440 static int rcu_bh_torture_completed(void)
442 return rcu_batches_completed_bh();
445 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
447 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
450 struct rcu_bh_torture_synchronize {
451 struct rcu_head head;
452 struct completion completion;
455 static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head)
457 struct rcu_bh_torture_synchronize *rcu;
459 rcu = container_of(head, struct rcu_bh_torture_synchronize, head);
460 complete(&rcu->completion);
463 static void rcu_bh_torture_synchronize(void)
465 struct rcu_bh_torture_synchronize rcu;
467 init_rcu_head_on_stack(&rcu.head);
468 init_completion(&rcu.completion);
469 call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
470 wait_for_completion(&rcu.completion);
471 destroy_rcu_head_on_stack(&rcu.head);
474 static struct rcu_torture_ops rcu_bh_ops = {
475 .init = NULL,
476 .cleanup = NULL,
477 .readlock = rcu_bh_torture_read_lock,
478 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
479 .readunlock = rcu_bh_torture_read_unlock,
480 .completed = rcu_bh_torture_completed,
481 .deferred_free = rcu_bh_torture_deferred_free,
482 .sync = rcu_bh_torture_synchronize,
483 .cb_barrier = rcu_barrier_bh,
484 .fqs = rcu_bh_force_quiescent_state,
485 .stats = NULL,
486 .irq_capable = 1,
487 .name = "rcu_bh"
490 static struct rcu_torture_ops rcu_bh_sync_ops = {
491 .init = rcu_sync_torture_init,
492 .cleanup = NULL,
493 .readlock = rcu_bh_torture_read_lock,
494 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
495 .readunlock = rcu_bh_torture_read_unlock,
496 .completed = rcu_bh_torture_completed,
497 .deferred_free = rcu_sync_torture_deferred_free,
498 .sync = rcu_bh_torture_synchronize,
499 .cb_barrier = NULL,
500 .fqs = rcu_bh_force_quiescent_state,
501 .stats = NULL,
502 .irq_capable = 1,
503 .name = "rcu_bh_sync"
507 * Definitions for srcu torture testing.
510 static struct srcu_struct srcu_ctl;
512 static void srcu_torture_init(void)
514 init_srcu_struct(&srcu_ctl);
515 rcu_sync_torture_init();
518 static void srcu_torture_cleanup(void)
520 synchronize_srcu(&srcu_ctl);
521 cleanup_srcu_struct(&srcu_ctl);
524 static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
526 return srcu_read_lock(&srcu_ctl);
529 static void srcu_read_delay(struct rcu_random_state *rrsp)
531 long delay;
532 const long uspertick = 1000000 / HZ;
533 const long longdelay = 10;
535 /* We want there to be long-running readers, but not all the time. */
537 delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
538 if (!delay)
539 schedule_timeout_interruptible(longdelay);
542 static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
544 srcu_read_unlock(&srcu_ctl, idx);
547 static int srcu_torture_completed(void)
549 return srcu_batches_completed(&srcu_ctl);
552 static void srcu_torture_synchronize(void)
554 synchronize_srcu(&srcu_ctl);
557 static int srcu_torture_stats(char *page)
559 int cnt = 0;
560 int cpu;
561 int idx = srcu_ctl.completed & 0x1;
563 cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
564 torture_type, TORTURE_FLAG, idx);
565 for_each_possible_cpu(cpu) {
566 cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu,
567 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
568 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
570 cnt += sprintf(&page[cnt], "\n");
571 return cnt;
574 static struct rcu_torture_ops srcu_ops = {
575 .init = srcu_torture_init,
576 .cleanup = srcu_torture_cleanup,
577 .readlock = srcu_torture_read_lock,
578 .read_delay = srcu_read_delay,
579 .readunlock = srcu_torture_read_unlock,
580 .completed = srcu_torture_completed,
581 .deferred_free = rcu_sync_torture_deferred_free,
582 .sync = srcu_torture_synchronize,
583 .cb_barrier = NULL,
584 .stats = srcu_torture_stats,
585 .name = "srcu"
588 static void srcu_torture_synchronize_expedited(void)
590 synchronize_srcu_expedited(&srcu_ctl);
593 static struct rcu_torture_ops srcu_expedited_ops = {
594 .init = srcu_torture_init,
595 .cleanup = srcu_torture_cleanup,
596 .readlock = srcu_torture_read_lock,
597 .read_delay = srcu_read_delay,
598 .readunlock = srcu_torture_read_unlock,
599 .completed = srcu_torture_completed,
600 .deferred_free = rcu_sync_torture_deferred_free,
601 .sync = srcu_torture_synchronize_expedited,
602 .cb_barrier = NULL,
603 .stats = srcu_torture_stats,
604 .name = "srcu_expedited"
608 * Definitions for sched torture testing.
611 static int sched_torture_read_lock(void)
613 preempt_disable();
614 return 0;
617 static void sched_torture_read_unlock(int idx)
619 preempt_enable();
622 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
624 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
627 static void sched_torture_synchronize(void)
629 synchronize_sched();
632 static struct rcu_torture_ops sched_ops = {
633 .init = rcu_sync_torture_init,
634 .cleanup = NULL,
635 .readlock = sched_torture_read_lock,
636 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
637 .readunlock = sched_torture_read_unlock,
638 .completed = rcu_no_completed,
639 .deferred_free = rcu_sched_torture_deferred_free,
640 .sync = sched_torture_synchronize,
641 .cb_barrier = rcu_barrier_sched,
642 .fqs = rcu_sched_force_quiescent_state,
643 .stats = NULL,
644 .irq_capable = 1,
645 .name = "sched"
648 static struct rcu_torture_ops sched_sync_ops = {
649 .init = rcu_sync_torture_init,
650 .cleanup = NULL,
651 .readlock = sched_torture_read_lock,
652 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
653 .readunlock = sched_torture_read_unlock,
654 .completed = rcu_no_completed,
655 .deferred_free = rcu_sync_torture_deferred_free,
656 .sync = sched_torture_synchronize,
657 .cb_barrier = NULL,
658 .fqs = rcu_sched_force_quiescent_state,
659 .stats = NULL,
660 .name = "sched_sync"
663 static struct rcu_torture_ops sched_expedited_ops = {
664 .init = rcu_sync_torture_init,
665 .cleanup = NULL,
666 .readlock = sched_torture_read_lock,
667 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
668 .readunlock = sched_torture_read_unlock,
669 .completed = rcu_no_completed,
670 .deferred_free = rcu_sync_torture_deferred_free,
671 .sync = synchronize_sched_expedited,
672 .cb_barrier = NULL,
673 .fqs = rcu_sched_force_quiescent_state,
674 .stats = NULL,
675 .irq_capable = 1,
676 .name = "sched_expedited"
680 * RCU torture force-quiescent-state kthread. Repeatedly induces
681 * bursts of calls to force_quiescent_state(), increasing the probability
682 * of occurrence of some important types of race conditions.
684 static int
685 rcu_torture_fqs(void *arg)
687 unsigned long fqs_resume_time;
688 int fqs_burst_remaining;
690 VERBOSE_PRINTK_STRING("rcu_torture_fqs task started");
691 do {
692 fqs_resume_time = jiffies + fqs_stutter * HZ;
693 while (jiffies - fqs_resume_time > LONG_MAX) {
694 schedule_timeout_interruptible(1);
696 fqs_burst_remaining = fqs_duration;
697 while (fqs_burst_remaining > 0) {
698 cur_ops->fqs();
699 udelay(fqs_holdoff);
700 fqs_burst_remaining -= fqs_holdoff;
702 rcu_stutter_wait("rcu_torture_fqs");
703 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
704 VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping");
705 rcutorture_shutdown_absorb("rcu_torture_fqs");
706 while (!kthread_should_stop())
707 schedule_timeout_uninterruptible(1);
708 return 0;
712 * RCU torture writer kthread. Repeatedly substitutes a new structure
713 * for that pointed to by rcu_torture_current, freeing the old structure
714 * after a series of grace periods (the "pipeline").
716 static int
717 rcu_torture_writer(void *arg)
719 int i;
720 long oldbatch = rcu_batches_completed();
721 struct rcu_torture *rp;
722 struct rcu_torture *old_rp;
723 static DEFINE_RCU_RANDOM(rand);
725 VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
726 set_user_nice(current, 19);
728 do {
729 schedule_timeout_uninterruptible(1);
730 rp = rcu_torture_alloc();
731 if (rp == NULL)
732 continue;
733 rp->rtort_pipe_count = 0;
734 udelay(rcu_random(&rand) & 0x3ff);
735 old_rp = rcu_torture_current;
736 rp->rtort_mbtest = 1;
737 rcu_assign_pointer(rcu_torture_current, rp);
738 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
739 if (old_rp) {
740 i = old_rp->rtort_pipe_count;
741 if (i > RCU_TORTURE_PIPE_LEN)
742 i = RCU_TORTURE_PIPE_LEN;
743 atomic_inc(&rcu_torture_wcount[i]);
744 old_rp->rtort_pipe_count++;
745 cur_ops->deferred_free(old_rp);
747 rcu_torture_current_version++;
748 oldbatch = cur_ops->completed();
749 rcu_stutter_wait("rcu_torture_writer");
750 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
751 VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
752 rcutorture_shutdown_absorb("rcu_torture_writer");
753 while (!kthread_should_stop())
754 schedule_timeout_uninterruptible(1);
755 return 0;
759 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
760 * delay between calls.
762 static int
763 rcu_torture_fakewriter(void *arg)
765 DEFINE_RCU_RANDOM(rand);
767 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
768 set_user_nice(current, 19);
770 do {
771 schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
772 udelay(rcu_random(&rand) & 0x3ff);
773 cur_ops->sync();
774 rcu_stutter_wait("rcu_torture_fakewriter");
775 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
777 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
778 rcutorture_shutdown_absorb("rcu_torture_fakewriter");
779 while (!kthread_should_stop())
780 schedule_timeout_uninterruptible(1);
781 return 0;
785 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
786 * incrementing the corresponding element of the pipeline array. The
787 * counter in the element should never be greater than 1, otherwise, the
788 * RCU implementation is broken.
790 static void rcu_torture_timer(unsigned long unused)
792 int idx;
793 int completed;
794 static DEFINE_RCU_RANDOM(rand);
795 static DEFINE_SPINLOCK(rand_lock);
796 struct rcu_torture *p;
797 int pipe_count;
799 idx = cur_ops->readlock();
800 completed = cur_ops->completed();
801 p = rcu_dereference_check(rcu_torture_current,
802 rcu_read_lock_held() ||
803 rcu_read_lock_bh_held() ||
804 rcu_read_lock_sched_held() ||
805 srcu_read_lock_held(&srcu_ctl));
806 if (p == NULL) {
807 /* Leave because rcu_torture_writer is not yet underway */
808 cur_ops->readunlock(idx);
809 return;
811 if (p->rtort_mbtest == 0)
812 atomic_inc(&n_rcu_torture_mberror);
813 spin_lock(&rand_lock);
814 cur_ops->read_delay(&rand);
815 n_rcu_torture_timers++;
816 spin_unlock(&rand_lock);
817 preempt_disable();
818 pipe_count = p->rtort_pipe_count;
819 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
820 /* Should not happen, but... */
821 pipe_count = RCU_TORTURE_PIPE_LEN;
823 __this_cpu_inc(rcu_torture_count[pipe_count]);
824 completed = cur_ops->completed() - completed;
825 if (completed > RCU_TORTURE_PIPE_LEN) {
826 /* Should not happen, but... */
827 completed = RCU_TORTURE_PIPE_LEN;
829 __this_cpu_inc(rcu_torture_batch[completed]);
830 preempt_enable();
831 cur_ops->readunlock(idx);
835 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
836 * incrementing the corresponding element of the pipeline array. The
837 * counter in the element should never be greater than 1, otherwise, the
838 * RCU implementation is broken.
840 static int
841 rcu_torture_reader(void *arg)
843 int completed;
844 int idx;
845 DEFINE_RCU_RANDOM(rand);
846 struct rcu_torture *p;
847 int pipe_count;
848 struct timer_list t;
850 VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
851 set_user_nice(current, 19);
852 if (irqreader && cur_ops->irq_capable)
853 setup_timer_on_stack(&t, rcu_torture_timer, 0);
855 do {
856 if (irqreader && cur_ops->irq_capable) {
857 if (!timer_pending(&t))
858 mod_timer(&t, jiffies + 1);
860 idx = cur_ops->readlock();
861 completed = cur_ops->completed();
862 p = rcu_dereference_check(rcu_torture_current,
863 rcu_read_lock_held() ||
864 rcu_read_lock_bh_held() ||
865 rcu_read_lock_sched_held() ||
866 srcu_read_lock_held(&srcu_ctl));
867 if (p == NULL) {
868 /* Wait for rcu_torture_writer to get underway */
869 cur_ops->readunlock(idx);
870 schedule_timeout_interruptible(HZ);
871 continue;
873 if (p->rtort_mbtest == 0)
874 atomic_inc(&n_rcu_torture_mberror);
875 cur_ops->read_delay(&rand);
876 preempt_disable();
877 pipe_count = p->rtort_pipe_count;
878 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
879 /* Should not happen, but... */
880 pipe_count = RCU_TORTURE_PIPE_LEN;
882 __this_cpu_inc(rcu_torture_count[pipe_count]);
883 completed = cur_ops->completed() - completed;
884 if (completed > RCU_TORTURE_PIPE_LEN) {
885 /* Should not happen, but... */
886 completed = RCU_TORTURE_PIPE_LEN;
888 __this_cpu_inc(rcu_torture_batch[completed]);
889 preempt_enable();
890 cur_ops->readunlock(idx);
891 schedule();
892 rcu_stutter_wait("rcu_torture_reader");
893 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
894 VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
895 rcutorture_shutdown_absorb("rcu_torture_reader");
896 if (irqreader && cur_ops->irq_capable)
897 del_timer_sync(&t);
898 while (!kthread_should_stop())
899 schedule_timeout_uninterruptible(1);
900 return 0;
904 * Create an RCU-torture statistics message in the specified buffer.
906 static int
907 rcu_torture_printk(char *page)
909 int cnt = 0;
910 int cpu;
911 int i;
912 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
913 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
915 for_each_possible_cpu(cpu) {
916 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
917 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
918 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
921 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
922 if (pipesummary[i] != 0)
923 break;
925 cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
926 cnt += sprintf(&page[cnt],
927 "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
928 "rtmbe: %d nt: %ld",
929 rcu_torture_current,
930 rcu_torture_current_version,
931 list_empty(&rcu_torture_freelist),
932 atomic_read(&n_rcu_torture_alloc),
933 atomic_read(&n_rcu_torture_alloc_fail),
934 atomic_read(&n_rcu_torture_free),
935 atomic_read(&n_rcu_torture_mberror),
936 n_rcu_torture_timers);
937 if (atomic_read(&n_rcu_torture_mberror) != 0)
938 cnt += sprintf(&page[cnt], " !!!");
939 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
940 if (i > 1) {
941 cnt += sprintf(&page[cnt], "!!! ");
942 atomic_inc(&n_rcu_torture_error);
943 WARN_ON_ONCE(1);
945 cnt += sprintf(&page[cnt], "Reader Pipe: ");
946 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
947 cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
948 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
949 cnt += sprintf(&page[cnt], "Reader Batch: ");
950 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
951 cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
952 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
953 cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
954 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
955 cnt += sprintf(&page[cnt], " %d",
956 atomic_read(&rcu_torture_wcount[i]));
958 cnt += sprintf(&page[cnt], "\n");
959 if (cur_ops->stats)
960 cnt += cur_ops->stats(&page[cnt]);
961 return cnt;
965 * Print torture statistics. Caller must ensure that there is only
966 * one call to this function at a given time!!! This is normally
967 * accomplished by relying on the module system to only have one copy
968 * of the module loaded, and then by giving the rcu_torture_stats
969 * kthread full control (or the init/cleanup functions when rcu_torture_stats
970 * thread is not running).
972 static void
973 rcu_torture_stats_print(void)
975 int cnt;
977 cnt = rcu_torture_printk(printk_buf);
978 printk(KERN_ALERT "%s", printk_buf);
982 * Periodically prints torture statistics, if periodic statistics printing
983 * was specified via the stat_interval module parameter.
985 * No need to worry about fullstop here, since this one doesn't reference
986 * volatile state or register callbacks.
988 static int
989 rcu_torture_stats(void *arg)
991 VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
992 do {
993 schedule_timeout_interruptible(stat_interval * HZ);
994 rcu_torture_stats_print();
995 rcutorture_shutdown_absorb("rcu_torture_stats");
996 } while (!kthread_should_stop());
997 VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
998 return 0;
1001 static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
1003 /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
1004 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
1006 static void rcu_torture_shuffle_tasks(void)
1008 int i;
1010 cpumask_setall(shuffle_tmp_mask);
1011 get_online_cpus();
1013 /* No point in shuffling if there is only one online CPU (ex: UP) */
1014 if (num_online_cpus() == 1) {
1015 put_online_cpus();
1016 return;
1019 if (rcu_idle_cpu != -1)
1020 cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
1022 set_cpus_allowed_ptr(current, shuffle_tmp_mask);
1024 if (reader_tasks) {
1025 for (i = 0; i < nrealreaders; i++)
1026 if (reader_tasks[i])
1027 set_cpus_allowed_ptr(reader_tasks[i],
1028 shuffle_tmp_mask);
1031 if (fakewriter_tasks) {
1032 for (i = 0; i < nfakewriters; i++)
1033 if (fakewriter_tasks[i])
1034 set_cpus_allowed_ptr(fakewriter_tasks[i],
1035 shuffle_tmp_mask);
1038 if (writer_task)
1039 set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
1041 if (stats_task)
1042 set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
1044 if (rcu_idle_cpu == -1)
1045 rcu_idle_cpu = num_online_cpus() - 1;
1046 else
1047 rcu_idle_cpu--;
1049 put_online_cpus();
1052 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
1053 * system to become idle at a time and cut off its timer ticks. This is meant
1054 * to test the support for such tickless idle CPU in RCU.
1056 static int
1057 rcu_torture_shuffle(void *arg)
1059 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
1060 do {
1061 schedule_timeout_interruptible(shuffle_interval * HZ);
1062 rcu_torture_shuffle_tasks();
1063 rcutorture_shutdown_absorb("rcu_torture_shuffle");
1064 } while (!kthread_should_stop());
1065 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
1066 return 0;
1069 /* Cause the rcutorture test to "stutter", starting and stopping all
1070 * threads periodically.
1072 static int
1073 rcu_torture_stutter(void *arg)
1075 VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
1076 do {
1077 schedule_timeout_interruptible(stutter * HZ);
1078 stutter_pause_test = 1;
1079 if (!kthread_should_stop())
1080 schedule_timeout_interruptible(stutter * HZ);
1081 stutter_pause_test = 0;
1082 rcutorture_shutdown_absorb("rcu_torture_stutter");
1083 } while (!kthread_should_stop());
1084 VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
1085 return 0;
1088 static inline void
1089 rcu_torture_print_module_parms(char *tag)
1091 printk(KERN_ALERT "%s" TORTURE_FLAG
1092 "--- %s: nreaders=%d nfakewriters=%d "
1093 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1094 "shuffle_interval=%d stutter=%d irqreader=%d "
1095 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d\n",
1096 torture_type, tag, nrealreaders, nfakewriters,
1097 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1098 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter);
1101 static struct notifier_block rcutorture_nb = {
1102 .notifier_call = rcutorture_shutdown_notify,
1105 static void
1106 rcu_torture_cleanup(void)
1108 int i;
1110 mutex_lock(&fullstop_mutex);
1111 if (fullstop == FULLSTOP_SHUTDOWN) {
1112 printk(KERN_WARNING /* but going down anyway, so... */
1113 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
1114 mutex_unlock(&fullstop_mutex);
1115 schedule_timeout_uninterruptible(10);
1116 if (cur_ops->cb_barrier != NULL)
1117 cur_ops->cb_barrier();
1118 return;
1120 fullstop = FULLSTOP_RMMOD;
1121 mutex_unlock(&fullstop_mutex);
1122 unregister_reboot_notifier(&rcutorture_nb);
1123 if (stutter_task) {
1124 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1125 kthread_stop(stutter_task);
1127 stutter_task = NULL;
1128 if (shuffler_task) {
1129 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1130 kthread_stop(shuffler_task);
1131 free_cpumask_var(shuffle_tmp_mask);
1133 shuffler_task = NULL;
1135 if (writer_task) {
1136 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1137 kthread_stop(writer_task);
1139 writer_task = NULL;
1141 if (reader_tasks) {
1142 for (i = 0; i < nrealreaders; i++) {
1143 if (reader_tasks[i]) {
1144 VERBOSE_PRINTK_STRING(
1145 "Stopping rcu_torture_reader task");
1146 kthread_stop(reader_tasks[i]);
1148 reader_tasks[i] = NULL;
1150 kfree(reader_tasks);
1151 reader_tasks = NULL;
1153 rcu_torture_current = NULL;
1155 if (fakewriter_tasks) {
1156 for (i = 0; i < nfakewriters; i++) {
1157 if (fakewriter_tasks[i]) {
1158 VERBOSE_PRINTK_STRING(
1159 "Stopping rcu_torture_fakewriter task");
1160 kthread_stop(fakewriter_tasks[i]);
1162 fakewriter_tasks[i] = NULL;
1164 kfree(fakewriter_tasks);
1165 fakewriter_tasks = NULL;
1168 if (stats_task) {
1169 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1170 kthread_stop(stats_task);
1172 stats_task = NULL;
1174 if (fqs_task) {
1175 VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task");
1176 kthread_stop(fqs_task);
1178 fqs_task = NULL;
1180 /* Wait for all RCU callbacks to fire. */
1182 if (cur_ops->cb_barrier != NULL)
1183 cur_ops->cb_barrier();
1185 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1187 if (cur_ops->cleanup)
1188 cur_ops->cleanup();
1189 if (atomic_read(&n_rcu_torture_error))
1190 rcu_torture_print_module_parms("End of test: FAILURE");
1191 else
1192 rcu_torture_print_module_parms("End of test: SUCCESS");
1195 static int __init
1196 rcu_torture_init(void)
1198 int i;
1199 int cpu;
1200 int firsterr = 0;
1201 static struct rcu_torture_ops *torture_ops[] =
1202 { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops,
1203 &rcu_bh_ops, &rcu_bh_sync_ops,
1204 &srcu_ops, &srcu_expedited_ops,
1205 &sched_ops, &sched_sync_ops, &sched_expedited_ops, };
1207 mutex_lock(&fullstop_mutex);
1209 /* Process args and tell the world that the torturer is on the job. */
1210 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1211 cur_ops = torture_ops[i];
1212 if (strcmp(torture_type, cur_ops->name) == 0)
1213 break;
1215 if (i == ARRAY_SIZE(torture_ops)) {
1216 printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n",
1217 torture_type);
1218 printk(KERN_ALERT "rcu-torture types:");
1219 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1220 printk(KERN_ALERT " %s", torture_ops[i]->name);
1221 printk(KERN_ALERT "\n");
1222 mutex_unlock(&fullstop_mutex);
1223 return -EINVAL;
1225 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1226 printk(KERN_ALERT "rcu-torture: ->fqs NULL and non-zero "
1227 "fqs_duration, fqs disabled.\n");
1228 fqs_duration = 0;
1230 if (cur_ops->init)
1231 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1233 if (nreaders >= 0)
1234 nrealreaders = nreaders;
1235 else
1236 nrealreaders = 2 * num_online_cpus();
1237 rcu_torture_print_module_parms("Start of test");
1238 fullstop = FULLSTOP_DONTSTOP;
1240 /* Set up the freelist. */
1242 INIT_LIST_HEAD(&rcu_torture_freelist);
1243 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1244 rcu_tortures[i].rtort_mbtest = 0;
1245 list_add_tail(&rcu_tortures[i].rtort_free,
1246 &rcu_torture_freelist);
1249 /* Initialize the statistics so that each run gets its own numbers. */
1251 rcu_torture_current = NULL;
1252 rcu_torture_current_version = 0;
1253 atomic_set(&n_rcu_torture_alloc, 0);
1254 atomic_set(&n_rcu_torture_alloc_fail, 0);
1255 atomic_set(&n_rcu_torture_free, 0);
1256 atomic_set(&n_rcu_torture_mberror, 0);
1257 atomic_set(&n_rcu_torture_error, 0);
1258 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1259 atomic_set(&rcu_torture_wcount[i], 0);
1260 for_each_possible_cpu(cpu) {
1261 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1262 per_cpu(rcu_torture_count, cpu)[i] = 0;
1263 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1267 /* Start up the kthreads. */
1269 VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
1270 writer_task = kthread_run(rcu_torture_writer, NULL,
1271 "rcu_torture_writer");
1272 if (IS_ERR(writer_task)) {
1273 firsterr = PTR_ERR(writer_task);
1274 VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
1275 writer_task = NULL;
1276 goto unwind;
1278 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1279 GFP_KERNEL);
1280 if (fakewriter_tasks == NULL) {
1281 VERBOSE_PRINTK_ERRSTRING("out of memory");
1282 firsterr = -ENOMEM;
1283 goto unwind;
1285 for (i = 0; i < nfakewriters; i++) {
1286 VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
1287 fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
1288 "rcu_torture_fakewriter");
1289 if (IS_ERR(fakewriter_tasks[i])) {
1290 firsterr = PTR_ERR(fakewriter_tasks[i]);
1291 VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
1292 fakewriter_tasks[i] = NULL;
1293 goto unwind;
1296 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1297 GFP_KERNEL);
1298 if (reader_tasks == NULL) {
1299 VERBOSE_PRINTK_ERRSTRING("out of memory");
1300 firsterr = -ENOMEM;
1301 goto unwind;
1303 for (i = 0; i < nrealreaders; i++) {
1304 VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
1305 reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
1306 "rcu_torture_reader");
1307 if (IS_ERR(reader_tasks[i])) {
1308 firsterr = PTR_ERR(reader_tasks[i]);
1309 VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
1310 reader_tasks[i] = NULL;
1311 goto unwind;
1314 if (stat_interval > 0) {
1315 VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
1316 stats_task = kthread_run(rcu_torture_stats, NULL,
1317 "rcu_torture_stats");
1318 if (IS_ERR(stats_task)) {
1319 firsterr = PTR_ERR(stats_task);
1320 VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
1321 stats_task = NULL;
1322 goto unwind;
1325 if (test_no_idle_hz) {
1326 rcu_idle_cpu = num_online_cpus() - 1;
1328 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
1329 firsterr = -ENOMEM;
1330 VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
1331 goto unwind;
1334 /* Create the shuffler thread */
1335 shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
1336 "rcu_torture_shuffle");
1337 if (IS_ERR(shuffler_task)) {
1338 free_cpumask_var(shuffle_tmp_mask);
1339 firsterr = PTR_ERR(shuffler_task);
1340 VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
1341 shuffler_task = NULL;
1342 goto unwind;
1345 if (stutter < 0)
1346 stutter = 0;
1347 if (stutter) {
1348 /* Create the stutter thread */
1349 stutter_task = kthread_run(rcu_torture_stutter, NULL,
1350 "rcu_torture_stutter");
1351 if (IS_ERR(stutter_task)) {
1352 firsterr = PTR_ERR(stutter_task);
1353 VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
1354 stutter_task = NULL;
1355 goto unwind;
1358 if (fqs_duration < 0)
1359 fqs_duration = 0;
1360 if (fqs_duration) {
1361 /* Create the stutter thread */
1362 fqs_task = kthread_run(rcu_torture_fqs, NULL,
1363 "rcu_torture_fqs");
1364 if (IS_ERR(fqs_task)) {
1365 firsterr = PTR_ERR(fqs_task);
1366 VERBOSE_PRINTK_ERRSTRING("Failed to create fqs");
1367 fqs_task = NULL;
1368 goto unwind;
1371 register_reboot_notifier(&rcutorture_nb);
1372 mutex_unlock(&fullstop_mutex);
1373 return 0;
1375 unwind:
1376 mutex_unlock(&fullstop_mutex);
1377 rcu_torture_cleanup();
1378 return firsterr;
1381 module_init(rcu_torture_init);
1382 module_exit(rcu_torture_cleanup);