tty: Fix a typo noted in passing
[linux-2.6/mini2440.git] / kernel / rcutorture.c
blobb33db539a8ad85037874c4505cf633cec450a394
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 (*read_delay)(struct rcu_random_state *rrsp);
261 void (*readunlock)(int idx);
262 int (*completed)(void);
263 void (*deferred_free)(struct rcu_torture *p);
264 void (*sync)(void);
265 void (*cb_barrier)(void);
266 int (*stats)(char *page);
267 int irq_capable;
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->deferred_free(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 .read_delay = rcu_read_delay,
336 .readunlock = rcu_torture_read_unlock,
337 .completed = rcu_torture_completed,
338 .deferred_free = rcu_torture_deferred_free,
339 .sync = synchronize_rcu,
340 .cb_barrier = rcu_barrier,
341 .stats = NULL,
342 .irq_capable = 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 .read_delay = rcu_read_delay,
377 .readunlock = rcu_torture_read_unlock,
378 .completed = rcu_torture_completed,
379 .deferred_free = rcu_sync_torture_deferred_free,
380 .sync = synchronize_rcu,
381 .cb_barrier = NULL,
382 .stats = NULL,
383 .irq_capable = 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 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
439 .readunlock = rcu_bh_torture_read_unlock,
440 .completed = rcu_bh_torture_completed,
441 .deferred_free = rcu_bh_torture_deferred_free,
442 .sync = rcu_bh_torture_synchronize,
443 .cb_barrier = rcu_barrier_bh,
444 .stats = NULL,
445 .irq_capable = 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 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
454 .readunlock = rcu_bh_torture_read_unlock,
455 .completed = rcu_bh_torture_completed,
456 .deferred_free = rcu_sync_torture_deferred_free,
457 .sync = rcu_bh_torture_synchronize,
458 .cb_barrier = NULL,
459 .stats = NULL,
460 .irq_capable = 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 .read_delay = srcu_read_delay,
537 .readunlock = srcu_torture_read_unlock,
538 .completed = srcu_torture_completed,
539 .deferred_free = 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 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
581 .readunlock = sched_torture_read_unlock,
582 .completed = sched_torture_completed,
583 .deferred_free = rcu_sched_torture_deferred_free,
584 .sync = sched_torture_synchronize,
585 .cb_barrier = rcu_barrier_sched,
586 .stats = NULL,
587 .irq_capable = 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 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
596 .readunlock = sched_torture_read_unlock,
597 .completed = sched_torture_completed,
598 .deferred_free = rcu_sync_torture_deferred_free,
599 .sync = sched_torture_synchronize,
600 .cb_barrier = NULL,
601 .stats = NULL,
602 .name = "sched_sync"
605 extern int rcu_expedited_torture_stats(char *page);
607 static struct rcu_torture_ops sched_expedited_ops = {
608 .init = rcu_sync_torture_init,
609 .cleanup = NULL,
610 .readlock = sched_torture_read_lock,
611 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
612 .readunlock = sched_torture_read_unlock,
613 .completed = sched_torture_completed,
614 .deferred_free = rcu_sync_torture_deferred_free,
615 .sync = synchronize_sched_expedited,
616 .cb_barrier = NULL,
617 .stats = rcu_expedited_torture_stats,
618 .irq_capable = 1,
619 .name = "sched_expedited"
623 * RCU torture writer kthread. Repeatedly substitutes a new structure
624 * for that pointed to by rcu_torture_current, freeing the old structure
625 * after a series of grace periods (the "pipeline").
627 static int
628 rcu_torture_writer(void *arg)
630 int i;
631 long oldbatch = rcu_batches_completed();
632 struct rcu_torture *rp;
633 struct rcu_torture *old_rp;
634 static DEFINE_RCU_RANDOM(rand);
636 VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
637 set_user_nice(current, 19);
639 do {
640 schedule_timeout_uninterruptible(1);
641 if ((rp = rcu_torture_alloc()) == NULL)
642 continue;
643 rp->rtort_pipe_count = 0;
644 udelay(rcu_random(&rand) & 0x3ff);
645 old_rp = rcu_torture_current;
646 rp->rtort_mbtest = 1;
647 rcu_assign_pointer(rcu_torture_current, rp);
648 smp_wmb();
649 if (old_rp) {
650 i = old_rp->rtort_pipe_count;
651 if (i > RCU_TORTURE_PIPE_LEN)
652 i = RCU_TORTURE_PIPE_LEN;
653 atomic_inc(&rcu_torture_wcount[i]);
654 old_rp->rtort_pipe_count++;
655 cur_ops->deferred_free(old_rp);
657 rcu_torture_current_version++;
658 oldbatch = cur_ops->completed();
659 rcu_stutter_wait("rcu_torture_writer");
660 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
661 VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
662 rcutorture_shutdown_absorb("rcu_torture_writer");
663 while (!kthread_should_stop())
664 schedule_timeout_uninterruptible(1);
665 return 0;
669 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
670 * delay between calls.
672 static int
673 rcu_torture_fakewriter(void *arg)
675 DEFINE_RCU_RANDOM(rand);
677 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
678 set_user_nice(current, 19);
680 do {
681 schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
682 udelay(rcu_random(&rand) & 0x3ff);
683 cur_ops->sync();
684 rcu_stutter_wait("rcu_torture_fakewriter");
685 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
687 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
688 rcutorture_shutdown_absorb("rcu_torture_fakewriter");
689 while (!kthread_should_stop())
690 schedule_timeout_uninterruptible(1);
691 return 0;
695 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
696 * incrementing the corresponding element of the pipeline array. The
697 * counter in the element should never be greater than 1, otherwise, the
698 * RCU implementation is broken.
700 static void rcu_torture_timer(unsigned long unused)
702 int idx;
703 int completed;
704 static DEFINE_RCU_RANDOM(rand);
705 static DEFINE_SPINLOCK(rand_lock);
706 struct rcu_torture *p;
707 int pipe_count;
709 idx = cur_ops->readlock();
710 completed = cur_ops->completed();
711 p = rcu_dereference(rcu_torture_current);
712 if (p == NULL) {
713 /* Leave because rcu_torture_writer is not yet underway */
714 cur_ops->readunlock(idx);
715 return;
717 if (p->rtort_mbtest == 0)
718 atomic_inc(&n_rcu_torture_mberror);
719 spin_lock(&rand_lock);
720 cur_ops->read_delay(&rand);
721 n_rcu_torture_timers++;
722 spin_unlock(&rand_lock);
723 preempt_disable();
724 pipe_count = p->rtort_pipe_count;
725 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
726 /* Should not happen, but... */
727 pipe_count = RCU_TORTURE_PIPE_LEN;
729 ++__get_cpu_var(rcu_torture_count)[pipe_count];
730 completed = cur_ops->completed() - completed;
731 if (completed > RCU_TORTURE_PIPE_LEN) {
732 /* Should not happen, but... */
733 completed = RCU_TORTURE_PIPE_LEN;
735 ++__get_cpu_var(rcu_torture_batch)[completed];
736 preempt_enable();
737 cur_ops->readunlock(idx);
741 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
742 * incrementing the corresponding element of the pipeline array. The
743 * counter in the element should never be greater than 1, otherwise, the
744 * RCU implementation is broken.
746 static int
747 rcu_torture_reader(void *arg)
749 int completed;
750 int idx;
751 DEFINE_RCU_RANDOM(rand);
752 struct rcu_torture *p;
753 int pipe_count;
754 struct timer_list t;
756 VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
757 set_user_nice(current, 19);
758 if (irqreader && cur_ops->irq_capable)
759 setup_timer_on_stack(&t, rcu_torture_timer, 0);
761 do {
762 if (irqreader && cur_ops->irq_capable) {
763 if (!timer_pending(&t))
764 mod_timer(&t, 1);
766 idx = cur_ops->readlock();
767 completed = cur_ops->completed();
768 p = rcu_dereference(rcu_torture_current);
769 if (p == NULL) {
770 /* Wait for rcu_torture_writer to get underway */
771 cur_ops->readunlock(idx);
772 schedule_timeout_interruptible(HZ);
773 continue;
775 if (p->rtort_mbtest == 0)
776 atomic_inc(&n_rcu_torture_mberror);
777 cur_ops->read_delay(&rand);
778 preempt_disable();
779 pipe_count = p->rtort_pipe_count;
780 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
781 /* Should not happen, but... */
782 pipe_count = RCU_TORTURE_PIPE_LEN;
784 ++__get_cpu_var(rcu_torture_count)[pipe_count];
785 completed = cur_ops->completed() - completed;
786 if (completed > RCU_TORTURE_PIPE_LEN) {
787 /* Should not happen, but... */
788 completed = RCU_TORTURE_PIPE_LEN;
790 ++__get_cpu_var(rcu_torture_batch)[completed];
791 preempt_enable();
792 cur_ops->readunlock(idx);
793 schedule();
794 rcu_stutter_wait("rcu_torture_reader");
795 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
796 VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
797 rcutorture_shutdown_absorb("rcu_torture_reader");
798 if (irqreader && cur_ops->irq_capable)
799 del_timer_sync(&t);
800 while (!kthread_should_stop())
801 schedule_timeout_uninterruptible(1);
802 return 0;
806 * Create an RCU-torture statistics message in the specified buffer.
808 static int
809 rcu_torture_printk(char *page)
811 int cnt = 0;
812 int cpu;
813 int i;
814 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
815 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
817 for_each_possible_cpu(cpu) {
818 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
819 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
820 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
823 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
824 if (pipesummary[i] != 0)
825 break;
827 cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
828 cnt += sprintf(&page[cnt],
829 "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
830 "rtmbe: %d nt: %ld",
831 rcu_torture_current,
832 rcu_torture_current_version,
833 list_empty(&rcu_torture_freelist),
834 atomic_read(&n_rcu_torture_alloc),
835 atomic_read(&n_rcu_torture_alloc_fail),
836 atomic_read(&n_rcu_torture_free),
837 atomic_read(&n_rcu_torture_mberror),
838 n_rcu_torture_timers);
839 if (atomic_read(&n_rcu_torture_mberror) != 0)
840 cnt += sprintf(&page[cnt], " !!!");
841 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
842 if (i > 1) {
843 cnt += sprintf(&page[cnt], "!!! ");
844 atomic_inc(&n_rcu_torture_error);
845 WARN_ON_ONCE(1);
847 cnt += sprintf(&page[cnt], "Reader Pipe: ");
848 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
849 cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
850 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
851 cnt += sprintf(&page[cnt], "Reader Batch: ");
852 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
853 cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
854 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
855 cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
856 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
857 cnt += sprintf(&page[cnt], " %d",
858 atomic_read(&rcu_torture_wcount[i]));
860 cnt += sprintf(&page[cnt], "\n");
861 if (cur_ops->stats)
862 cnt += cur_ops->stats(&page[cnt]);
863 return cnt;
867 * Print torture statistics. Caller must ensure that there is only
868 * one call to this function at a given time!!! This is normally
869 * accomplished by relying on the module system to only have one copy
870 * of the module loaded, and then by giving the rcu_torture_stats
871 * kthread full control (or the init/cleanup functions when rcu_torture_stats
872 * thread is not running).
874 static void
875 rcu_torture_stats_print(void)
877 int cnt;
879 cnt = rcu_torture_printk(printk_buf);
880 printk(KERN_ALERT "%s", printk_buf);
884 * Periodically prints torture statistics, if periodic statistics printing
885 * was specified via the stat_interval module parameter.
887 * No need to worry about fullstop here, since this one doesn't reference
888 * volatile state or register callbacks.
890 static int
891 rcu_torture_stats(void *arg)
893 VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
894 do {
895 schedule_timeout_interruptible(stat_interval * HZ);
896 rcu_torture_stats_print();
897 rcutorture_shutdown_absorb("rcu_torture_stats");
898 } while (!kthread_should_stop());
899 VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
900 return 0;
903 static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
905 /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
906 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
908 static void rcu_torture_shuffle_tasks(void)
910 int i;
912 cpumask_setall(shuffle_tmp_mask);
913 get_online_cpus();
915 /* No point in shuffling if there is only one online CPU (ex: UP) */
916 if (num_online_cpus() == 1) {
917 put_online_cpus();
918 return;
921 if (rcu_idle_cpu != -1)
922 cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
924 set_cpus_allowed_ptr(current, shuffle_tmp_mask);
926 if (reader_tasks) {
927 for (i = 0; i < nrealreaders; i++)
928 if (reader_tasks[i])
929 set_cpus_allowed_ptr(reader_tasks[i],
930 shuffle_tmp_mask);
933 if (fakewriter_tasks) {
934 for (i = 0; i < nfakewriters; i++)
935 if (fakewriter_tasks[i])
936 set_cpus_allowed_ptr(fakewriter_tasks[i],
937 shuffle_tmp_mask);
940 if (writer_task)
941 set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
943 if (stats_task)
944 set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
946 if (rcu_idle_cpu == -1)
947 rcu_idle_cpu = num_online_cpus() - 1;
948 else
949 rcu_idle_cpu--;
951 put_online_cpus();
954 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
955 * system to become idle at a time and cut off its timer ticks. This is meant
956 * to test the support for such tickless idle CPU in RCU.
958 static int
959 rcu_torture_shuffle(void *arg)
961 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
962 do {
963 schedule_timeout_interruptible(shuffle_interval * HZ);
964 rcu_torture_shuffle_tasks();
965 rcutorture_shutdown_absorb("rcu_torture_shuffle");
966 } while (!kthread_should_stop());
967 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
968 return 0;
971 /* Cause the rcutorture test to "stutter", starting and stopping all
972 * threads periodically.
974 static int
975 rcu_torture_stutter(void *arg)
977 VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
978 do {
979 schedule_timeout_interruptible(stutter * HZ);
980 stutter_pause_test = 1;
981 if (!kthread_should_stop())
982 schedule_timeout_interruptible(stutter * HZ);
983 stutter_pause_test = 0;
984 rcutorture_shutdown_absorb("rcu_torture_stutter");
985 } while (!kthread_should_stop());
986 VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
987 return 0;
990 static inline void
991 rcu_torture_print_module_parms(char *tag)
993 printk(KERN_ALERT "%s" TORTURE_FLAG
994 "--- %s: nreaders=%d nfakewriters=%d "
995 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
996 "shuffle_interval=%d stutter=%d irqreader=%d\n",
997 torture_type, tag, nrealreaders, nfakewriters,
998 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
999 stutter, irqreader);
1002 static struct notifier_block rcutorture_nb = {
1003 .notifier_call = rcutorture_shutdown_notify,
1006 static void
1007 rcu_torture_cleanup(void)
1009 int i;
1011 mutex_lock(&fullstop_mutex);
1012 if (fullstop == FULLSTOP_SHUTDOWN) {
1013 printk(KERN_WARNING /* but going down anyway, so... */
1014 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
1015 mutex_unlock(&fullstop_mutex);
1016 schedule_timeout_uninterruptible(10);
1017 if (cur_ops->cb_barrier != NULL)
1018 cur_ops->cb_barrier();
1019 return;
1021 fullstop = FULLSTOP_RMMOD;
1022 mutex_unlock(&fullstop_mutex);
1023 unregister_reboot_notifier(&rcutorture_nb);
1024 if (stutter_task) {
1025 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1026 kthread_stop(stutter_task);
1028 stutter_task = NULL;
1029 if (shuffler_task) {
1030 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1031 kthread_stop(shuffler_task);
1032 free_cpumask_var(shuffle_tmp_mask);
1034 shuffler_task = NULL;
1036 if (writer_task) {
1037 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1038 kthread_stop(writer_task);
1040 writer_task = NULL;
1042 if (reader_tasks) {
1043 for (i = 0; i < nrealreaders; i++) {
1044 if (reader_tasks[i]) {
1045 VERBOSE_PRINTK_STRING(
1046 "Stopping rcu_torture_reader task");
1047 kthread_stop(reader_tasks[i]);
1049 reader_tasks[i] = NULL;
1051 kfree(reader_tasks);
1052 reader_tasks = NULL;
1054 rcu_torture_current = NULL;
1056 if (fakewriter_tasks) {
1057 for (i = 0; i < nfakewriters; i++) {
1058 if (fakewriter_tasks[i]) {
1059 VERBOSE_PRINTK_STRING(
1060 "Stopping rcu_torture_fakewriter task");
1061 kthread_stop(fakewriter_tasks[i]);
1063 fakewriter_tasks[i] = NULL;
1065 kfree(fakewriter_tasks);
1066 fakewriter_tasks = NULL;
1069 if (stats_task) {
1070 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1071 kthread_stop(stats_task);
1073 stats_task = NULL;
1075 /* Wait for all RCU callbacks to fire. */
1077 if (cur_ops->cb_barrier != NULL)
1078 cur_ops->cb_barrier();
1080 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1082 if (cur_ops->cleanup)
1083 cur_ops->cleanup();
1084 if (atomic_read(&n_rcu_torture_error))
1085 rcu_torture_print_module_parms("End of test: FAILURE");
1086 else
1087 rcu_torture_print_module_parms("End of test: SUCCESS");
1090 static int __init
1091 rcu_torture_init(void)
1093 int i;
1094 int cpu;
1095 int firsterr = 0;
1096 static struct rcu_torture_ops *torture_ops[] =
1097 { &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops,
1098 &sched_expedited_ops,
1099 &srcu_ops, &sched_ops, &sched_ops_sync, };
1101 mutex_lock(&fullstop_mutex);
1103 /* Process args and tell the world that the torturer is on the job. */
1104 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1105 cur_ops = torture_ops[i];
1106 if (strcmp(torture_type, cur_ops->name) == 0)
1107 break;
1109 if (i == ARRAY_SIZE(torture_ops)) {
1110 printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n",
1111 torture_type);
1112 mutex_unlock(&fullstop_mutex);
1113 return (-EINVAL);
1115 if (cur_ops->init)
1116 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1118 if (nreaders >= 0)
1119 nrealreaders = nreaders;
1120 else
1121 nrealreaders = 2 * num_online_cpus();
1122 rcu_torture_print_module_parms("Start of test");
1123 fullstop = FULLSTOP_DONTSTOP;
1125 /* Set up the freelist. */
1127 INIT_LIST_HEAD(&rcu_torture_freelist);
1128 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1129 rcu_tortures[i].rtort_mbtest = 0;
1130 list_add_tail(&rcu_tortures[i].rtort_free,
1131 &rcu_torture_freelist);
1134 /* Initialize the statistics so that each run gets its own numbers. */
1136 rcu_torture_current = NULL;
1137 rcu_torture_current_version = 0;
1138 atomic_set(&n_rcu_torture_alloc, 0);
1139 atomic_set(&n_rcu_torture_alloc_fail, 0);
1140 atomic_set(&n_rcu_torture_free, 0);
1141 atomic_set(&n_rcu_torture_mberror, 0);
1142 atomic_set(&n_rcu_torture_error, 0);
1143 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1144 atomic_set(&rcu_torture_wcount[i], 0);
1145 for_each_possible_cpu(cpu) {
1146 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1147 per_cpu(rcu_torture_count, cpu)[i] = 0;
1148 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1152 /* Start up the kthreads. */
1154 VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
1155 writer_task = kthread_run(rcu_torture_writer, NULL,
1156 "rcu_torture_writer");
1157 if (IS_ERR(writer_task)) {
1158 firsterr = PTR_ERR(writer_task);
1159 VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
1160 writer_task = NULL;
1161 goto unwind;
1163 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1164 GFP_KERNEL);
1165 if (fakewriter_tasks == NULL) {
1166 VERBOSE_PRINTK_ERRSTRING("out of memory");
1167 firsterr = -ENOMEM;
1168 goto unwind;
1170 for (i = 0; i < nfakewriters; i++) {
1171 VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
1172 fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
1173 "rcu_torture_fakewriter");
1174 if (IS_ERR(fakewriter_tasks[i])) {
1175 firsterr = PTR_ERR(fakewriter_tasks[i]);
1176 VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
1177 fakewriter_tasks[i] = NULL;
1178 goto unwind;
1181 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1182 GFP_KERNEL);
1183 if (reader_tasks == NULL) {
1184 VERBOSE_PRINTK_ERRSTRING("out of memory");
1185 firsterr = -ENOMEM;
1186 goto unwind;
1188 for (i = 0; i < nrealreaders; i++) {
1189 VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
1190 reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
1191 "rcu_torture_reader");
1192 if (IS_ERR(reader_tasks[i])) {
1193 firsterr = PTR_ERR(reader_tasks[i]);
1194 VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
1195 reader_tasks[i] = NULL;
1196 goto unwind;
1199 if (stat_interval > 0) {
1200 VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
1201 stats_task = kthread_run(rcu_torture_stats, NULL,
1202 "rcu_torture_stats");
1203 if (IS_ERR(stats_task)) {
1204 firsterr = PTR_ERR(stats_task);
1205 VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
1206 stats_task = NULL;
1207 goto unwind;
1210 if (test_no_idle_hz) {
1211 rcu_idle_cpu = num_online_cpus() - 1;
1213 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
1214 firsterr = -ENOMEM;
1215 VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
1216 goto unwind;
1219 /* Create the shuffler thread */
1220 shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
1221 "rcu_torture_shuffle");
1222 if (IS_ERR(shuffler_task)) {
1223 free_cpumask_var(shuffle_tmp_mask);
1224 firsterr = PTR_ERR(shuffler_task);
1225 VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
1226 shuffler_task = NULL;
1227 goto unwind;
1230 if (stutter < 0)
1231 stutter = 0;
1232 if (stutter) {
1233 /* Create the stutter thread */
1234 stutter_task = kthread_run(rcu_torture_stutter, NULL,
1235 "rcu_torture_stutter");
1236 if (IS_ERR(stutter_task)) {
1237 firsterr = PTR_ERR(stutter_task);
1238 VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
1239 stutter_task = NULL;
1240 goto unwind;
1243 register_reboot_notifier(&rcutorture_nb);
1244 mutex_unlock(&fullstop_mutex);
1245 return 0;
1247 unwind:
1248 mutex_unlock(&fullstop_mutex);
1249 rcu_torture_cleanup();
1250 return firsterr;
1253 module_init(rcu_torture_init);
1254 module_exit(rcu_torture_cleanup);