OMAP2xxx clock: fix broken cpu_mask code
[linux-ginger.git] / kernel / rcutorture.c
blob9b4a975a4b4afc1f1eba22c1cb30d21aef844959
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 char *torture_type = "rcu"; /* What RCU implementation to torture. */
66 module_param(nreaders, int, 0444);
67 MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
68 module_param(nfakewriters, int, 0444);
69 MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
70 module_param(stat_interval, int, 0444);
71 MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
72 module_param(verbose, bool, 0444);
73 MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
74 module_param(test_no_idle_hz, bool, 0444);
75 MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
76 module_param(shuffle_interval, int, 0444);
77 MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
78 module_param(stutter, int, 0444);
79 MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
80 module_param(irqreader, int, 0444);
81 MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
82 module_param(torture_type, charp, 0444);
83 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
85 #define TORTURE_FLAG "-torture:"
86 #define PRINTK_STRING(s) \
87 do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
88 #define VERBOSE_PRINTK_STRING(s) \
89 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
90 #define VERBOSE_PRINTK_ERRSTRING(s) \
91 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
93 static char printk_buf[4096];
95 static int nrealreaders;
96 static struct task_struct *writer_task;
97 static struct task_struct **fakewriter_tasks;
98 static struct task_struct **reader_tasks;
99 static struct task_struct *stats_task;
100 static struct task_struct *shuffler_task;
101 static struct task_struct *stutter_task;
103 #define RCU_TORTURE_PIPE_LEN 10
105 struct rcu_torture {
106 struct rcu_head rtort_rcu;
107 int rtort_pipe_count;
108 struct list_head rtort_free;
109 int rtort_mbtest;
112 static LIST_HEAD(rcu_torture_freelist);
113 static struct rcu_torture *rcu_torture_current = NULL;
114 static long rcu_torture_current_version = 0;
115 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
116 static DEFINE_SPINLOCK(rcu_torture_lock);
117 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
118 { 0 };
119 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
120 { 0 };
121 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
122 static atomic_t n_rcu_torture_alloc;
123 static atomic_t n_rcu_torture_alloc_fail;
124 static atomic_t n_rcu_torture_free;
125 static atomic_t n_rcu_torture_mberror;
126 static atomic_t n_rcu_torture_error;
127 static long n_rcu_torture_timers = 0;
128 static struct list_head rcu_torture_removed;
129 static cpumask_var_t shuffle_tmp_mask;
131 static int stutter_pause_test = 0;
133 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
134 #define RCUTORTURE_RUNNABLE_INIT 1
135 #else
136 #define RCUTORTURE_RUNNABLE_INIT 0
137 #endif
138 int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
140 /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
142 #define FULLSTOP_DONTSTOP 0 /* Normal operation. */
143 #define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */
144 #define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */
145 static int fullstop = FULLSTOP_RMMOD;
146 DEFINE_MUTEX(fullstop_mutex); /* Protect fullstop transitions and spawning */
147 /* of kthreads. */
150 * Detect and respond to a system shutdown.
152 static int
153 rcutorture_shutdown_notify(struct notifier_block *unused1,
154 unsigned long unused2, void *unused3)
156 mutex_lock(&fullstop_mutex);
157 if (fullstop == FULLSTOP_DONTSTOP)
158 fullstop = FULLSTOP_SHUTDOWN;
159 else
160 printk(KERN_WARNING /* but going down anyway, so... */
161 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
162 mutex_unlock(&fullstop_mutex);
163 return NOTIFY_DONE;
167 * Absorb kthreads into a kernel function that won't return, so that
168 * they won't ever access module text or data again.
170 static void rcutorture_shutdown_absorb(char *title)
172 if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
173 printk(KERN_NOTICE
174 "rcutorture thread %s parking due to system shutdown\n",
175 title);
176 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
181 * Allocate an element from the rcu_tortures pool.
183 static struct rcu_torture *
184 rcu_torture_alloc(void)
186 struct list_head *p;
188 spin_lock_bh(&rcu_torture_lock);
189 if (list_empty(&rcu_torture_freelist)) {
190 atomic_inc(&n_rcu_torture_alloc_fail);
191 spin_unlock_bh(&rcu_torture_lock);
192 return NULL;
194 atomic_inc(&n_rcu_torture_alloc);
195 p = rcu_torture_freelist.next;
196 list_del_init(p);
197 spin_unlock_bh(&rcu_torture_lock);
198 return container_of(p, struct rcu_torture, rtort_free);
202 * Free an element to the rcu_tortures pool.
204 static void
205 rcu_torture_free(struct rcu_torture *p)
207 atomic_inc(&n_rcu_torture_free);
208 spin_lock_bh(&rcu_torture_lock);
209 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
210 spin_unlock_bh(&rcu_torture_lock);
213 struct rcu_random_state {
214 unsigned long rrs_state;
215 long rrs_count;
218 #define RCU_RANDOM_MULT 39916801 /* prime */
219 #define RCU_RANDOM_ADD 479001701 /* prime */
220 #define RCU_RANDOM_REFRESH 10000
222 #define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
225 * Crude but fast random-number generator. Uses a linear congruential
226 * generator, with occasional help from cpu_clock().
228 static unsigned long
229 rcu_random(struct rcu_random_state *rrsp)
231 if (--rrsp->rrs_count < 0) {
232 rrsp->rrs_state +=
233 (unsigned long)cpu_clock(raw_smp_processor_id());
234 rrsp->rrs_count = RCU_RANDOM_REFRESH;
236 rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
237 return swahw32(rrsp->rrs_state);
240 static void
241 rcu_stutter_wait(char *title)
243 while (stutter_pause_test || !rcutorture_runnable) {
244 if (rcutorture_runnable)
245 schedule_timeout_interruptible(1);
246 else
247 schedule_timeout_interruptible(round_jiffies_relative(HZ));
248 rcutorture_shutdown_absorb(title);
253 * Operations vector for selecting different types of tests.
256 struct rcu_torture_ops {
257 void (*init)(void);
258 void (*cleanup)(void);
259 int (*readlock)(void);
260 void (*readdelay)(struct rcu_random_state *rrsp);
261 void (*readunlock)(int idx);
262 int (*completed)(void);
263 void (*deferredfree)(struct rcu_torture *p);
264 void (*sync)(void);
265 void (*cb_barrier)(void);
266 int (*stats)(char *page);
267 int irqcapable;
268 char *name;
270 static struct rcu_torture_ops *cur_ops = NULL;
273 * Definitions for rcu torture testing.
276 static int rcu_torture_read_lock(void) __acquires(RCU)
278 rcu_read_lock();
279 return 0;
282 static void rcu_read_delay(struct rcu_random_state *rrsp)
284 long delay;
285 const long longdelay = 200;
287 /* We want there to be long-running readers, but not all the time. */
289 delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay);
290 if (!delay)
291 udelay(longdelay);
294 static void rcu_torture_read_unlock(int idx) __releases(RCU)
296 rcu_read_unlock();
299 static int rcu_torture_completed(void)
301 return rcu_batches_completed();
304 static void
305 rcu_torture_cb(struct rcu_head *p)
307 int i;
308 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
310 if (fullstop != FULLSTOP_DONTSTOP) {
311 /* Test is ending, just drop callbacks on the floor. */
312 /* The next initialization will pick up the pieces. */
313 return;
315 i = rp->rtort_pipe_count;
316 if (i > RCU_TORTURE_PIPE_LEN)
317 i = RCU_TORTURE_PIPE_LEN;
318 atomic_inc(&rcu_torture_wcount[i]);
319 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
320 rp->rtort_mbtest = 0;
321 rcu_torture_free(rp);
322 } else
323 cur_ops->deferredfree(rp);
326 static void rcu_torture_deferred_free(struct rcu_torture *p)
328 call_rcu(&p->rtort_rcu, rcu_torture_cb);
331 static struct rcu_torture_ops rcu_ops = {
332 .init = NULL,
333 .cleanup = NULL,
334 .readlock = rcu_torture_read_lock,
335 .readdelay = rcu_read_delay,
336 .readunlock = rcu_torture_read_unlock,
337 .completed = rcu_torture_completed,
338 .deferredfree = rcu_torture_deferred_free,
339 .sync = synchronize_rcu,
340 .cb_barrier = rcu_barrier,
341 .stats = NULL,
342 .irqcapable = 1,
343 .name = "rcu"
346 static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
348 int i;
349 struct rcu_torture *rp;
350 struct rcu_torture *rp1;
352 cur_ops->sync();
353 list_add(&p->rtort_free, &rcu_torture_removed);
354 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
355 i = rp->rtort_pipe_count;
356 if (i > RCU_TORTURE_PIPE_LEN)
357 i = RCU_TORTURE_PIPE_LEN;
358 atomic_inc(&rcu_torture_wcount[i]);
359 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
360 rp->rtort_mbtest = 0;
361 list_del(&rp->rtort_free);
362 rcu_torture_free(rp);
367 static void rcu_sync_torture_init(void)
369 INIT_LIST_HEAD(&rcu_torture_removed);
372 static struct rcu_torture_ops rcu_sync_ops = {
373 .init = rcu_sync_torture_init,
374 .cleanup = NULL,
375 .readlock = rcu_torture_read_lock,
376 .readdelay = rcu_read_delay,
377 .readunlock = rcu_torture_read_unlock,
378 .completed = rcu_torture_completed,
379 .deferredfree = rcu_sync_torture_deferred_free,
380 .sync = synchronize_rcu,
381 .cb_barrier = NULL,
382 .stats = NULL,
383 .irqcapable = 1,
384 .name = "rcu_sync"
388 * Definitions for rcu_bh torture testing.
391 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
393 rcu_read_lock_bh();
394 return 0;
397 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
399 rcu_read_unlock_bh();
402 static int rcu_bh_torture_completed(void)
404 return rcu_batches_completed_bh();
407 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
409 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
412 struct rcu_bh_torture_synchronize {
413 struct rcu_head head;
414 struct completion completion;
417 static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head)
419 struct rcu_bh_torture_synchronize *rcu;
421 rcu = container_of(head, struct rcu_bh_torture_synchronize, head);
422 complete(&rcu->completion);
425 static void rcu_bh_torture_synchronize(void)
427 struct rcu_bh_torture_synchronize rcu;
429 init_completion(&rcu.completion);
430 call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
431 wait_for_completion(&rcu.completion);
434 static struct rcu_torture_ops rcu_bh_ops = {
435 .init = NULL,
436 .cleanup = NULL,
437 .readlock = rcu_bh_torture_read_lock,
438 .readdelay = rcu_read_delay, /* just reuse rcu's version. */
439 .readunlock = rcu_bh_torture_read_unlock,
440 .completed = rcu_bh_torture_completed,
441 .deferredfree = rcu_bh_torture_deferred_free,
442 .sync = rcu_bh_torture_synchronize,
443 .cb_barrier = rcu_barrier_bh,
444 .stats = NULL,
445 .irqcapable = 1,
446 .name = "rcu_bh"
449 static struct rcu_torture_ops rcu_bh_sync_ops = {
450 .init = rcu_sync_torture_init,
451 .cleanup = NULL,
452 .readlock = rcu_bh_torture_read_lock,
453 .readdelay = rcu_read_delay, /* just reuse rcu's version. */
454 .readunlock = rcu_bh_torture_read_unlock,
455 .completed = rcu_bh_torture_completed,
456 .deferredfree = rcu_sync_torture_deferred_free,
457 .sync = rcu_bh_torture_synchronize,
458 .cb_barrier = NULL,
459 .stats = NULL,
460 .irqcapable = 1,
461 .name = "rcu_bh_sync"
465 * Definitions for srcu torture testing.
468 static struct srcu_struct srcu_ctl;
470 static void srcu_torture_init(void)
472 init_srcu_struct(&srcu_ctl);
473 rcu_sync_torture_init();
476 static void srcu_torture_cleanup(void)
478 synchronize_srcu(&srcu_ctl);
479 cleanup_srcu_struct(&srcu_ctl);
482 static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
484 return srcu_read_lock(&srcu_ctl);
487 static void srcu_read_delay(struct rcu_random_state *rrsp)
489 long delay;
490 const long uspertick = 1000000 / HZ;
491 const long longdelay = 10;
493 /* We want there to be long-running readers, but not all the time. */
495 delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
496 if (!delay)
497 schedule_timeout_interruptible(longdelay);
500 static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
502 srcu_read_unlock(&srcu_ctl, idx);
505 static int srcu_torture_completed(void)
507 return srcu_batches_completed(&srcu_ctl);
510 static void srcu_torture_synchronize(void)
512 synchronize_srcu(&srcu_ctl);
515 static int srcu_torture_stats(char *page)
517 int cnt = 0;
518 int cpu;
519 int idx = srcu_ctl.completed & 0x1;
521 cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
522 torture_type, TORTURE_FLAG, idx);
523 for_each_possible_cpu(cpu) {
524 cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu,
525 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
526 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
528 cnt += sprintf(&page[cnt], "\n");
529 return cnt;
532 static struct rcu_torture_ops srcu_ops = {
533 .init = srcu_torture_init,
534 .cleanup = srcu_torture_cleanup,
535 .readlock = srcu_torture_read_lock,
536 .readdelay = srcu_read_delay,
537 .readunlock = srcu_torture_read_unlock,
538 .completed = srcu_torture_completed,
539 .deferredfree = rcu_sync_torture_deferred_free,
540 .sync = srcu_torture_synchronize,
541 .cb_barrier = NULL,
542 .stats = srcu_torture_stats,
543 .name = "srcu"
547 * Definitions for sched torture testing.
550 static int sched_torture_read_lock(void)
552 preempt_disable();
553 return 0;
556 static void sched_torture_read_unlock(int idx)
558 preempt_enable();
561 static int sched_torture_completed(void)
563 return 0;
566 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
568 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
571 static void sched_torture_synchronize(void)
573 synchronize_sched();
576 static struct rcu_torture_ops sched_ops = {
577 .init = rcu_sync_torture_init,
578 .cleanup = NULL,
579 .readlock = sched_torture_read_lock,
580 .readdelay = rcu_read_delay, /* just reuse rcu's version. */
581 .readunlock = sched_torture_read_unlock,
582 .completed = sched_torture_completed,
583 .deferredfree = rcu_sched_torture_deferred_free,
584 .sync = sched_torture_synchronize,
585 .cb_barrier = rcu_barrier_sched,
586 .stats = NULL,
587 .irqcapable = 1,
588 .name = "sched"
591 static struct rcu_torture_ops sched_ops_sync = {
592 .init = rcu_sync_torture_init,
593 .cleanup = NULL,
594 .readlock = sched_torture_read_lock,
595 .readdelay = rcu_read_delay, /* just reuse rcu's version. */
596 .readunlock = sched_torture_read_unlock,
597 .completed = sched_torture_completed,
598 .deferredfree = rcu_sync_torture_deferred_free,
599 .sync = sched_torture_synchronize,
600 .cb_barrier = NULL,
601 .stats = NULL,
602 .name = "sched_sync"
606 * RCU torture writer kthread. Repeatedly substitutes a new structure
607 * for that pointed to by rcu_torture_current, freeing the old structure
608 * after a series of grace periods (the "pipeline").
610 static int
611 rcu_torture_writer(void *arg)
613 int i;
614 long oldbatch = rcu_batches_completed();
615 struct rcu_torture *rp;
616 struct rcu_torture *old_rp;
617 static DEFINE_RCU_RANDOM(rand);
619 VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
620 set_user_nice(current, 19);
622 do {
623 schedule_timeout_uninterruptible(1);
624 if ((rp = rcu_torture_alloc()) == NULL)
625 continue;
626 rp->rtort_pipe_count = 0;
627 udelay(rcu_random(&rand) & 0x3ff);
628 old_rp = rcu_torture_current;
629 rp->rtort_mbtest = 1;
630 rcu_assign_pointer(rcu_torture_current, rp);
631 smp_wmb();
632 if (old_rp) {
633 i = old_rp->rtort_pipe_count;
634 if (i > RCU_TORTURE_PIPE_LEN)
635 i = RCU_TORTURE_PIPE_LEN;
636 atomic_inc(&rcu_torture_wcount[i]);
637 old_rp->rtort_pipe_count++;
638 cur_ops->deferredfree(old_rp);
640 rcu_torture_current_version++;
641 oldbatch = cur_ops->completed();
642 rcu_stutter_wait("rcu_torture_writer");
643 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
644 VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
645 rcutorture_shutdown_absorb("rcu_torture_writer");
646 while (!kthread_should_stop())
647 schedule_timeout_uninterruptible(1);
648 return 0;
652 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
653 * delay between calls.
655 static int
656 rcu_torture_fakewriter(void *arg)
658 DEFINE_RCU_RANDOM(rand);
660 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
661 set_user_nice(current, 19);
663 do {
664 schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
665 udelay(rcu_random(&rand) & 0x3ff);
666 cur_ops->sync();
667 rcu_stutter_wait("rcu_torture_fakewriter");
668 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
670 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
671 rcutorture_shutdown_absorb("rcu_torture_fakewriter");
672 while (!kthread_should_stop())
673 schedule_timeout_uninterruptible(1);
674 return 0;
678 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
679 * incrementing the corresponding element of the pipeline array. The
680 * counter in the element should never be greater than 1, otherwise, the
681 * RCU implementation is broken.
683 static void rcu_torture_timer(unsigned long unused)
685 int idx;
686 int completed;
687 static DEFINE_RCU_RANDOM(rand);
688 static DEFINE_SPINLOCK(rand_lock);
689 struct rcu_torture *p;
690 int pipe_count;
692 idx = cur_ops->readlock();
693 completed = cur_ops->completed();
694 p = rcu_dereference(rcu_torture_current);
695 if (p == NULL) {
696 /* Leave because rcu_torture_writer is not yet underway */
697 cur_ops->readunlock(idx);
698 return;
700 if (p->rtort_mbtest == 0)
701 atomic_inc(&n_rcu_torture_mberror);
702 spin_lock(&rand_lock);
703 cur_ops->readdelay(&rand);
704 n_rcu_torture_timers++;
705 spin_unlock(&rand_lock);
706 preempt_disable();
707 pipe_count = p->rtort_pipe_count;
708 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
709 /* Should not happen, but... */
710 pipe_count = RCU_TORTURE_PIPE_LEN;
712 ++__get_cpu_var(rcu_torture_count)[pipe_count];
713 completed = cur_ops->completed() - completed;
714 if (completed > RCU_TORTURE_PIPE_LEN) {
715 /* Should not happen, but... */
716 completed = RCU_TORTURE_PIPE_LEN;
718 ++__get_cpu_var(rcu_torture_batch)[completed];
719 preempt_enable();
720 cur_ops->readunlock(idx);
724 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
725 * incrementing the corresponding element of the pipeline array. The
726 * counter in the element should never be greater than 1, otherwise, the
727 * RCU implementation is broken.
729 static int
730 rcu_torture_reader(void *arg)
732 int completed;
733 int idx;
734 DEFINE_RCU_RANDOM(rand);
735 struct rcu_torture *p;
736 int pipe_count;
737 struct timer_list t;
739 VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
740 set_user_nice(current, 19);
741 if (irqreader && cur_ops->irqcapable)
742 setup_timer_on_stack(&t, rcu_torture_timer, 0);
744 do {
745 if (irqreader && cur_ops->irqcapable) {
746 if (!timer_pending(&t))
747 mod_timer(&t, 1);
749 idx = cur_ops->readlock();
750 completed = cur_ops->completed();
751 p = rcu_dereference(rcu_torture_current);
752 if (p == NULL) {
753 /* Wait for rcu_torture_writer to get underway */
754 cur_ops->readunlock(idx);
755 schedule_timeout_interruptible(HZ);
756 continue;
758 if (p->rtort_mbtest == 0)
759 atomic_inc(&n_rcu_torture_mberror);
760 cur_ops->readdelay(&rand);
761 preempt_disable();
762 pipe_count = p->rtort_pipe_count;
763 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
764 /* Should not happen, but... */
765 pipe_count = RCU_TORTURE_PIPE_LEN;
767 ++__get_cpu_var(rcu_torture_count)[pipe_count];
768 completed = cur_ops->completed() - completed;
769 if (completed > RCU_TORTURE_PIPE_LEN) {
770 /* Should not happen, but... */
771 completed = RCU_TORTURE_PIPE_LEN;
773 ++__get_cpu_var(rcu_torture_batch)[completed];
774 preempt_enable();
775 cur_ops->readunlock(idx);
776 schedule();
777 rcu_stutter_wait("rcu_torture_reader");
778 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
779 VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
780 rcutorture_shutdown_absorb("rcu_torture_reader");
781 if (irqreader && cur_ops->irqcapable)
782 del_timer_sync(&t);
783 while (!kthread_should_stop())
784 schedule_timeout_uninterruptible(1);
785 return 0;
789 * Create an RCU-torture statistics message in the specified buffer.
791 static int
792 rcu_torture_printk(char *page)
794 int cnt = 0;
795 int cpu;
796 int i;
797 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
798 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
800 for_each_possible_cpu(cpu) {
801 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
802 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
803 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
806 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
807 if (pipesummary[i] != 0)
808 break;
810 cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
811 cnt += sprintf(&page[cnt],
812 "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
813 "rtmbe: %d nt: %ld",
814 rcu_torture_current,
815 rcu_torture_current_version,
816 list_empty(&rcu_torture_freelist),
817 atomic_read(&n_rcu_torture_alloc),
818 atomic_read(&n_rcu_torture_alloc_fail),
819 atomic_read(&n_rcu_torture_free),
820 atomic_read(&n_rcu_torture_mberror),
821 n_rcu_torture_timers);
822 if (atomic_read(&n_rcu_torture_mberror) != 0)
823 cnt += sprintf(&page[cnt], " !!!");
824 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
825 if (i > 1) {
826 cnt += sprintf(&page[cnt], "!!! ");
827 atomic_inc(&n_rcu_torture_error);
828 WARN_ON_ONCE(1);
830 cnt += sprintf(&page[cnt], "Reader Pipe: ");
831 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
832 cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
833 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
834 cnt += sprintf(&page[cnt], "Reader Batch: ");
835 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
836 cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
837 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
838 cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
839 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
840 cnt += sprintf(&page[cnt], " %d",
841 atomic_read(&rcu_torture_wcount[i]));
843 cnt += sprintf(&page[cnt], "\n");
844 if (cur_ops->stats)
845 cnt += cur_ops->stats(&page[cnt]);
846 return cnt;
850 * Print torture statistics. Caller must ensure that there is only
851 * one call to this function at a given time!!! This is normally
852 * accomplished by relying on the module system to only have one copy
853 * of the module loaded, and then by giving the rcu_torture_stats
854 * kthread full control (or the init/cleanup functions when rcu_torture_stats
855 * thread is not running).
857 static void
858 rcu_torture_stats_print(void)
860 int cnt;
862 cnt = rcu_torture_printk(printk_buf);
863 printk(KERN_ALERT "%s", printk_buf);
867 * Periodically prints torture statistics, if periodic statistics printing
868 * was specified via the stat_interval module parameter.
870 * No need to worry about fullstop here, since this one doesn't reference
871 * volatile state or register callbacks.
873 static int
874 rcu_torture_stats(void *arg)
876 VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
877 do {
878 schedule_timeout_interruptible(stat_interval * HZ);
879 rcu_torture_stats_print();
880 rcutorture_shutdown_absorb("rcu_torture_stats");
881 } while (!kthread_should_stop());
882 VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
883 return 0;
886 static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
888 /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
889 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
891 static void rcu_torture_shuffle_tasks(void)
893 int i;
895 cpumask_setall(shuffle_tmp_mask);
896 get_online_cpus();
898 /* No point in shuffling if there is only one online CPU (ex: UP) */
899 if (num_online_cpus() == 1) {
900 put_online_cpus();
901 return;
904 if (rcu_idle_cpu != -1)
905 cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
907 set_cpus_allowed_ptr(current, shuffle_tmp_mask);
909 if (reader_tasks) {
910 for (i = 0; i < nrealreaders; i++)
911 if (reader_tasks[i])
912 set_cpus_allowed_ptr(reader_tasks[i],
913 shuffle_tmp_mask);
916 if (fakewriter_tasks) {
917 for (i = 0; i < nfakewriters; i++)
918 if (fakewriter_tasks[i])
919 set_cpus_allowed_ptr(fakewriter_tasks[i],
920 shuffle_tmp_mask);
923 if (writer_task)
924 set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
926 if (stats_task)
927 set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
929 if (rcu_idle_cpu == -1)
930 rcu_idle_cpu = num_online_cpus() - 1;
931 else
932 rcu_idle_cpu--;
934 put_online_cpus();
937 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
938 * system to become idle at a time and cut off its timer ticks. This is meant
939 * to test the support for such tickless idle CPU in RCU.
941 static int
942 rcu_torture_shuffle(void *arg)
944 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
945 do {
946 schedule_timeout_interruptible(shuffle_interval * HZ);
947 rcu_torture_shuffle_tasks();
948 rcutorture_shutdown_absorb("rcu_torture_shuffle");
949 } while (!kthread_should_stop());
950 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
951 return 0;
954 /* Cause the rcutorture test to "stutter", starting and stopping all
955 * threads periodically.
957 static int
958 rcu_torture_stutter(void *arg)
960 VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
961 do {
962 schedule_timeout_interruptible(stutter * HZ);
963 stutter_pause_test = 1;
964 if (!kthread_should_stop())
965 schedule_timeout_interruptible(stutter * HZ);
966 stutter_pause_test = 0;
967 rcutorture_shutdown_absorb("rcu_torture_stutter");
968 } while (!kthread_should_stop());
969 VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
970 return 0;
973 static inline void
974 rcu_torture_print_module_parms(char *tag)
976 printk(KERN_ALERT "%s" TORTURE_FLAG
977 "--- %s: nreaders=%d nfakewriters=%d "
978 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
979 "shuffle_interval=%d stutter=%d irqreader=%d\n",
980 torture_type, tag, nrealreaders, nfakewriters,
981 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
982 stutter, irqreader);
985 static struct notifier_block rcutorture_nb = {
986 .notifier_call = rcutorture_shutdown_notify,
989 static void
990 rcu_torture_cleanup(void)
992 int i;
994 mutex_lock(&fullstop_mutex);
995 if (fullstop == FULLSTOP_SHUTDOWN) {
996 printk(KERN_WARNING /* but going down anyway, so... */
997 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
998 mutex_unlock(&fullstop_mutex);
999 schedule_timeout_uninterruptible(10);
1000 if (cur_ops->cb_barrier != NULL)
1001 cur_ops->cb_barrier();
1002 return;
1004 fullstop = FULLSTOP_RMMOD;
1005 mutex_unlock(&fullstop_mutex);
1006 unregister_reboot_notifier(&rcutorture_nb);
1007 if (stutter_task) {
1008 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1009 kthread_stop(stutter_task);
1011 stutter_task = NULL;
1012 if (shuffler_task) {
1013 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1014 kthread_stop(shuffler_task);
1015 free_cpumask_var(shuffle_tmp_mask);
1017 shuffler_task = NULL;
1019 if (writer_task) {
1020 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1021 kthread_stop(writer_task);
1023 writer_task = NULL;
1025 if (reader_tasks) {
1026 for (i = 0; i < nrealreaders; i++) {
1027 if (reader_tasks[i]) {
1028 VERBOSE_PRINTK_STRING(
1029 "Stopping rcu_torture_reader task");
1030 kthread_stop(reader_tasks[i]);
1032 reader_tasks[i] = NULL;
1034 kfree(reader_tasks);
1035 reader_tasks = NULL;
1037 rcu_torture_current = NULL;
1039 if (fakewriter_tasks) {
1040 for (i = 0; i < nfakewriters; i++) {
1041 if (fakewriter_tasks[i]) {
1042 VERBOSE_PRINTK_STRING(
1043 "Stopping rcu_torture_fakewriter task");
1044 kthread_stop(fakewriter_tasks[i]);
1046 fakewriter_tasks[i] = NULL;
1048 kfree(fakewriter_tasks);
1049 fakewriter_tasks = NULL;
1052 if (stats_task) {
1053 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1054 kthread_stop(stats_task);
1056 stats_task = NULL;
1058 /* Wait for all RCU callbacks to fire. */
1060 if (cur_ops->cb_barrier != NULL)
1061 cur_ops->cb_barrier();
1063 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1065 if (cur_ops->cleanup)
1066 cur_ops->cleanup();
1067 if (atomic_read(&n_rcu_torture_error))
1068 rcu_torture_print_module_parms("End of test: FAILURE");
1069 else
1070 rcu_torture_print_module_parms("End of test: SUCCESS");
1073 static int __init
1074 rcu_torture_init(void)
1076 int i;
1077 int cpu;
1078 int firsterr = 0;
1079 static struct rcu_torture_ops *torture_ops[] =
1080 { &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops,
1081 &srcu_ops, &sched_ops, &sched_ops_sync, };
1083 mutex_lock(&fullstop_mutex);
1085 /* Process args and tell the world that the torturer is on the job. */
1086 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1087 cur_ops = torture_ops[i];
1088 if (strcmp(torture_type, cur_ops->name) == 0)
1089 break;
1091 if (i == ARRAY_SIZE(torture_ops)) {
1092 printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n",
1093 torture_type);
1094 mutex_unlock(&fullstop_mutex);
1095 return (-EINVAL);
1097 if (cur_ops->init)
1098 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1100 if (nreaders >= 0)
1101 nrealreaders = nreaders;
1102 else
1103 nrealreaders = 2 * num_online_cpus();
1104 rcu_torture_print_module_parms("Start of test");
1105 fullstop = FULLSTOP_DONTSTOP;
1107 /* Set up the freelist. */
1109 INIT_LIST_HEAD(&rcu_torture_freelist);
1110 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1111 rcu_tortures[i].rtort_mbtest = 0;
1112 list_add_tail(&rcu_tortures[i].rtort_free,
1113 &rcu_torture_freelist);
1116 /* Initialize the statistics so that each run gets its own numbers. */
1118 rcu_torture_current = NULL;
1119 rcu_torture_current_version = 0;
1120 atomic_set(&n_rcu_torture_alloc, 0);
1121 atomic_set(&n_rcu_torture_alloc_fail, 0);
1122 atomic_set(&n_rcu_torture_free, 0);
1123 atomic_set(&n_rcu_torture_mberror, 0);
1124 atomic_set(&n_rcu_torture_error, 0);
1125 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1126 atomic_set(&rcu_torture_wcount[i], 0);
1127 for_each_possible_cpu(cpu) {
1128 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1129 per_cpu(rcu_torture_count, cpu)[i] = 0;
1130 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1134 /* Start up the kthreads. */
1136 VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
1137 writer_task = kthread_run(rcu_torture_writer, NULL,
1138 "rcu_torture_writer");
1139 if (IS_ERR(writer_task)) {
1140 firsterr = PTR_ERR(writer_task);
1141 VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
1142 writer_task = NULL;
1143 goto unwind;
1145 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1146 GFP_KERNEL);
1147 if (fakewriter_tasks == NULL) {
1148 VERBOSE_PRINTK_ERRSTRING("out of memory");
1149 firsterr = -ENOMEM;
1150 goto unwind;
1152 for (i = 0; i < nfakewriters; i++) {
1153 VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
1154 fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
1155 "rcu_torture_fakewriter");
1156 if (IS_ERR(fakewriter_tasks[i])) {
1157 firsterr = PTR_ERR(fakewriter_tasks[i]);
1158 VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
1159 fakewriter_tasks[i] = NULL;
1160 goto unwind;
1163 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1164 GFP_KERNEL);
1165 if (reader_tasks == NULL) {
1166 VERBOSE_PRINTK_ERRSTRING("out of memory");
1167 firsterr = -ENOMEM;
1168 goto unwind;
1170 for (i = 0; i < nrealreaders; i++) {
1171 VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
1172 reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
1173 "rcu_torture_reader");
1174 if (IS_ERR(reader_tasks[i])) {
1175 firsterr = PTR_ERR(reader_tasks[i]);
1176 VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
1177 reader_tasks[i] = NULL;
1178 goto unwind;
1181 if (stat_interval > 0) {
1182 VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
1183 stats_task = kthread_run(rcu_torture_stats, NULL,
1184 "rcu_torture_stats");
1185 if (IS_ERR(stats_task)) {
1186 firsterr = PTR_ERR(stats_task);
1187 VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
1188 stats_task = NULL;
1189 goto unwind;
1192 if (test_no_idle_hz) {
1193 rcu_idle_cpu = num_online_cpus() - 1;
1195 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
1196 firsterr = -ENOMEM;
1197 VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
1198 goto unwind;
1201 /* Create the shuffler thread */
1202 shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
1203 "rcu_torture_shuffle");
1204 if (IS_ERR(shuffler_task)) {
1205 free_cpumask_var(shuffle_tmp_mask);
1206 firsterr = PTR_ERR(shuffler_task);
1207 VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
1208 shuffler_task = NULL;
1209 goto unwind;
1212 if (stutter < 0)
1213 stutter = 0;
1214 if (stutter) {
1215 /* Create the stutter thread */
1216 stutter_task = kthread_run(rcu_torture_stutter, NULL,
1217 "rcu_torture_stutter");
1218 if (IS_ERR(stutter_task)) {
1219 firsterr = PTR_ERR(stutter_task);
1220 VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
1221 stutter_task = NULL;
1222 goto unwind;
1225 register_reboot_notifier(&rcutorture_nb);
1226 mutex_unlock(&fullstop_mutex);
1227 return 0;
1229 unwind:
1230 mutex_unlock(&fullstop_mutex);
1231 rcu_torture_cleanup();
1232 return firsterr;
1235 module_init(rcu_torture_init);
1236 module_exit(rcu_torture_cleanup);