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
106 struct rcu_head rtort_rcu;
107 int rtort_pipe_count;
108 struct list_head rtort_free;
112 static LIST_HEAD(rcu_torture_freelist);
113 static struct rcu_torture *rcu_torture_current;
114 static long rcu_torture_current_version;
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) =
119 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
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;
128 static struct list_head rcu_torture_removed;
129 static cpumask_var_t shuffle_tmp_mask;
131 static int stutter_pause_test;
133 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
134 #define RCUTORTURE_RUNNABLE_INIT 1
136 #define RCUTORTURE_RUNNABLE_INIT 0
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 */
150 * Detect and respond to a system shutdown.
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;
160 printk(KERN_WARNING /* but going down anyway, so... */
161 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
162 mutex_unlock(&fullstop_mutex);
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) {
174 "rcutorture thread %s parking due to system shutdown\n",
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)
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);
194 atomic_inc(&n_rcu_torture_alloc);
195 p = rcu_torture_freelist.next;
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.
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;
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().
229 rcu_random(struct rcu_random_state *rrsp)
231 if (--rrsp->rrs_count < 0) {
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);
241 rcu_stutter_wait(char *title)
243 while (stutter_pause_test || !rcutorture_runnable) {
244 if (rcutorture_runnable)
245 schedule_timeout_interruptible(1);
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 {
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);
265 void (*cb_barrier)(void);
266 int (*stats)(char *page);
271 static struct rcu_torture_ops *cur_ops;
274 * Definitions for rcu torture testing.
277 static int rcu_torture_read_lock(void) __acquires(RCU)
283 static void rcu_read_delay(struct rcu_random_state *rrsp)
285 const unsigned long shortdelay_us = 200;
286 const unsigned long longdelay_ms = 50;
288 /* We want a short delay sometimes to make a reader delay the grace
289 * period, and we want a long delay occasionally to trigger
290 * force_quiescent_state. */
292 if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
293 mdelay(longdelay_ms);
294 if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
295 udelay(shortdelay_us);
298 static void rcu_torture_read_unlock(int idx) __releases(RCU)
303 static int rcu_torture_completed(void)
305 return rcu_batches_completed();
309 rcu_torture_cb(struct rcu_head *p)
312 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
314 if (fullstop != FULLSTOP_DONTSTOP) {
315 /* Test is ending, just drop callbacks on the floor. */
316 /* The next initialization will pick up the pieces. */
319 i = rp->rtort_pipe_count;
320 if (i > RCU_TORTURE_PIPE_LEN)
321 i = RCU_TORTURE_PIPE_LEN;
322 atomic_inc(&rcu_torture_wcount[i]);
323 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
324 rp->rtort_mbtest = 0;
325 rcu_torture_free(rp);
327 cur_ops->deferred_free(rp);
330 static int rcu_no_completed(void)
335 static void rcu_torture_deferred_free(struct rcu_torture *p)
337 call_rcu(&p->rtort_rcu, rcu_torture_cb);
340 static struct rcu_torture_ops rcu_ops = {
343 .readlock = rcu_torture_read_lock,
344 .read_delay = rcu_read_delay,
345 .readunlock = rcu_torture_read_unlock,
346 .completed = rcu_torture_completed,
347 .deferred_free = rcu_torture_deferred_free,
348 .sync = synchronize_rcu,
349 .cb_barrier = rcu_barrier,
355 static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
358 struct rcu_torture *rp;
359 struct rcu_torture *rp1;
362 list_add(&p->rtort_free, &rcu_torture_removed);
363 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
364 i = rp->rtort_pipe_count;
365 if (i > RCU_TORTURE_PIPE_LEN)
366 i = RCU_TORTURE_PIPE_LEN;
367 atomic_inc(&rcu_torture_wcount[i]);
368 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
369 rp->rtort_mbtest = 0;
370 list_del(&rp->rtort_free);
371 rcu_torture_free(rp);
376 static void rcu_sync_torture_init(void)
378 INIT_LIST_HEAD(&rcu_torture_removed);
381 static struct rcu_torture_ops rcu_sync_ops = {
382 .init = rcu_sync_torture_init,
384 .readlock = rcu_torture_read_lock,
385 .read_delay = rcu_read_delay,
386 .readunlock = rcu_torture_read_unlock,
387 .completed = rcu_torture_completed,
388 .deferred_free = rcu_sync_torture_deferred_free,
389 .sync = synchronize_rcu,
396 static struct rcu_torture_ops rcu_expedited_ops = {
397 .init = rcu_sync_torture_init,
399 .readlock = rcu_torture_read_lock,
400 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
401 .readunlock = rcu_torture_read_unlock,
402 .completed = rcu_no_completed,
403 .deferred_free = rcu_sync_torture_deferred_free,
404 .sync = synchronize_rcu_expedited,
408 .name = "rcu_expedited"
412 * Definitions for rcu_bh torture testing.
415 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
421 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
423 rcu_read_unlock_bh();
426 static int rcu_bh_torture_completed(void)
428 return rcu_batches_completed_bh();
431 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
433 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
436 struct rcu_bh_torture_synchronize {
437 struct rcu_head head;
438 struct completion completion;
441 static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head)
443 struct rcu_bh_torture_synchronize *rcu;
445 rcu = container_of(head, struct rcu_bh_torture_synchronize, head);
446 complete(&rcu->completion);
449 static void rcu_bh_torture_synchronize(void)
451 struct rcu_bh_torture_synchronize rcu;
453 init_completion(&rcu.completion);
454 call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
455 wait_for_completion(&rcu.completion);
458 static struct rcu_torture_ops rcu_bh_ops = {
461 .readlock = rcu_bh_torture_read_lock,
462 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
463 .readunlock = rcu_bh_torture_read_unlock,
464 .completed = rcu_bh_torture_completed,
465 .deferred_free = rcu_bh_torture_deferred_free,
466 .sync = rcu_bh_torture_synchronize,
467 .cb_barrier = rcu_barrier_bh,
473 static struct rcu_torture_ops rcu_bh_sync_ops = {
474 .init = rcu_sync_torture_init,
476 .readlock = rcu_bh_torture_read_lock,
477 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
478 .readunlock = rcu_bh_torture_read_unlock,
479 .completed = rcu_bh_torture_completed,
480 .deferred_free = rcu_sync_torture_deferred_free,
481 .sync = rcu_bh_torture_synchronize,
485 .name = "rcu_bh_sync"
489 * Definitions for srcu torture testing.
492 static struct srcu_struct srcu_ctl;
494 static void srcu_torture_init(void)
496 init_srcu_struct(&srcu_ctl);
497 rcu_sync_torture_init();
500 static void srcu_torture_cleanup(void)
502 synchronize_srcu(&srcu_ctl);
503 cleanup_srcu_struct(&srcu_ctl);
506 static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
508 return srcu_read_lock(&srcu_ctl);
511 static void srcu_read_delay(struct rcu_random_state *rrsp)
514 const long uspertick = 1000000 / HZ;
515 const long longdelay = 10;
517 /* We want there to be long-running readers, but not all the time. */
519 delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
521 schedule_timeout_interruptible(longdelay);
524 static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
526 srcu_read_unlock(&srcu_ctl, idx);
529 static int srcu_torture_completed(void)
531 return srcu_batches_completed(&srcu_ctl);
534 static void srcu_torture_synchronize(void)
536 synchronize_srcu(&srcu_ctl);
539 static int srcu_torture_stats(char *page)
543 int idx = srcu_ctl.completed & 0x1;
545 cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
546 torture_type, TORTURE_FLAG, idx);
547 for_each_possible_cpu(cpu) {
548 cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu,
549 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
550 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
552 cnt += sprintf(&page[cnt], "\n");
556 static struct rcu_torture_ops srcu_ops = {
557 .init = srcu_torture_init,
558 .cleanup = srcu_torture_cleanup,
559 .readlock = srcu_torture_read_lock,
560 .read_delay = srcu_read_delay,
561 .readunlock = srcu_torture_read_unlock,
562 .completed = srcu_torture_completed,
563 .deferred_free = rcu_sync_torture_deferred_free,
564 .sync = srcu_torture_synchronize,
566 .stats = srcu_torture_stats,
570 static void srcu_torture_synchronize_expedited(void)
572 synchronize_srcu_expedited(&srcu_ctl);
575 static struct rcu_torture_ops srcu_expedited_ops = {
576 .init = srcu_torture_init,
577 .cleanup = srcu_torture_cleanup,
578 .readlock = srcu_torture_read_lock,
579 .read_delay = srcu_read_delay,
580 .readunlock = srcu_torture_read_unlock,
581 .completed = srcu_torture_completed,
582 .deferred_free = rcu_sync_torture_deferred_free,
583 .sync = srcu_torture_synchronize_expedited,
585 .stats = srcu_torture_stats,
586 .name = "srcu_expedited"
590 * Definitions for sched torture testing.
593 static int sched_torture_read_lock(void)
599 static void sched_torture_read_unlock(int idx)
604 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
606 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
609 static void sched_torture_synchronize(void)
614 static struct rcu_torture_ops sched_ops = {
615 .init = rcu_sync_torture_init,
617 .readlock = sched_torture_read_lock,
618 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
619 .readunlock = sched_torture_read_unlock,
620 .completed = rcu_no_completed,
621 .deferred_free = rcu_sched_torture_deferred_free,
622 .sync = sched_torture_synchronize,
623 .cb_barrier = rcu_barrier_sched,
629 static struct rcu_torture_ops sched_sync_ops = {
630 .init = rcu_sync_torture_init,
632 .readlock = sched_torture_read_lock,
633 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
634 .readunlock = sched_torture_read_unlock,
635 .completed = rcu_no_completed,
636 .deferred_free = rcu_sync_torture_deferred_free,
637 .sync = sched_torture_synchronize,
643 static struct rcu_torture_ops sched_expedited_ops = {
644 .init = rcu_sync_torture_init,
646 .readlock = sched_torture_read_lock,
647 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
648 .readunlock = sched_torture_read_unlock,
649 .completed = rcu_no_completed,
650 .deferred_free = rcu_sync_torture_deferred_free,
651 .sync = synchronize_sched_expedited,
653 .stats = rcu_expedited_torture_stats,
655 .name = "sched_expedited"
659 * RCU torture writer kthread. Repeatedly substitutes a new structure
660 * for that pointed to by rcu_torture_current, freeing the old structure
661 * after a series of grace periods (the "pipeline").
664 rcu_torture_writer(void *arg)
667 long oldbatch = rcu_batches_completed();
668 struct rcu_torture *rp;
669 struct rcu_torture *old_rp;
670 static DEFINE_RCU_RANDOM(rand);
672 VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
673 set_user_nice(current, 19);
676 schedule_timeout_uninterruptible(1);
677 rp = rcu_torture_alloc();
680 rp->rtort_pipe_count = 0;
681 udelay(rcu_random(&rand) & 0x3ff);
682 old_rp = rcu_torture_current;
683 rp->rtort_mbtest = 1;
684 rcu_assign_pointer(rcu_torture_current, rp);
685 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
687 i = old_rp->rtort_pipe_count;
688 if (i > RCU_TORTURE_PIPE_LEN)
689 i = RCU_TORTURE_PIPE_LEN;
690 atomic_inc(&rcu_torture_wcount[i]);
691 old_rp->rtort_pipe_count++;
692 cur_ops->deferred_free(old_rp);
694 rcu_torture_current_version++;
695 oldbatch = cur_ops->completed();
696 rcu_stutter_wait("rcu_torture_writer");
697 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
698 VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
699 rcutorture_shutdown_absorb("rcu_torture_writer");
700 while (!kthread_should_stop())
701 schedule_timeout_uninterruptible(1);
706 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
707 * delay between calls.
710 rcu_torture_fakewriter(void *arg)
712 DEFINE_RCU_RANDOM(rand);
714 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
715 set_user_nice(current, 19);
718 schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
719 udelay(rcu_random(&rand) & 0x3ff);
721 rcu_stutter_wait("rcu_torture_fakewriter");
722 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
724 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
725 rcutorture_shutdown_absorb("rcu_torture_fakewriter");
726 while (!kthread_should_stop())
727 schedule_timeout_uninterruptible(1);
732 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
733 * incrementing the corresponding element of the pipeline array. The
734 * counter in the element should never be greater than 1, otherwise, the
735 * RCU implementation is broken.
737 static void rcu_torture_timer(unsigned long unused)
741 static DEFINE_RCU_RANDOM(rand);
742 static DEFINE_SPINLOCK(rand_lock);
743 struct rcu_torture *p;
746 idx = cur_ops->readlock();
747 completed = cur_ops->completed();
748 p = rcu_dereference(rcu_torture_current);
750 /* Leave because rcu_torture_writer is not yet underway */
751 cur_ops->readunlock(idx);
754 if (p->rtort_mbtest == 0)
755 atomic_inc(&n_rcu_torture_mberror);
756 spin_lock(&rand_lock);
757 cur_ops->read_delay(&rand);
758 n_rcu_torture_timers++;
759 spin_unlock(&rand_lock);
761 pipe_count = p->rtort_pipe_count;
762 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
763 /* Should not happen, but... */
764 pipe_count = RCU_TORTURE_PIPE_LEN;
766 ++__get_cpu_var(rcu_torture_count)[pipe_count];
767 completed = cur_ops->completed() - completed;
768 if (completed > RCU_TORTURE_PIPE_LEN) {
769 /* Should not happen, but... */
770 completed = RCU_TORTURE_PIPE_LEN;
772 ++__get_cpu_var(rcu_torture_batch)[completed];
774 cur_ops->readunlock(idx);
778 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
779 * incrementing the corresponding element of the pipeline array. The
780 * counter in the element should never be greater than 1, otherwise, the
781 * RCU implementation is broken.
784 rcu_torture_reader(void *arg)
788 DEFINE_RCU_RANDOM(rand);
789 struct rcu_torture *p;
793 VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
794 set_user_nice(current, 19);
795 if (irqreader && cur_ops->irq_capable)
796 setup_timer_on_stack(&t, rcu_torture_timer, 0);
799 if (irqreader && cur_ops->irq_capable) {
800 if (!timer_pending(&t))
803 idx = cur_ops->readlock();
804 completed = cur_ops->completed();
805 p = rcu_dereference(rcu_torture_current);
807 /* Wait for rcu_torture_writer to get underway */
808 cur_ops->readunlock(idx);
809 schedule_timeout_interruptible(HZ);
812 if (p->rtort_mbtest == 0)
813 atomic_inc(&n_rcu_torture_mberror);
814 cur_ops->read_delay(&rand);
816 pipe_count = p->rtort_pipe_count;
817 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
818 /* Should not happen, but... */
819 pipe_count = RCU_TORTURE_PIPE_LEN;
821 ++__get_cpu_var(rcu_torture_count)[pipe_count];
822 completed = cur_ops->completed() - completed;
823 if (completed > RCU_TORTURE_PIPE_LEN) {
824 /* Should not happen, but... */
825 completed = RCU_TORTURE_PIPE_LEN;
827 ++__get_cpu_var(rcu_torture_batch)[completed];
829 cur_ops->readunlock(idx);
831 rcu_stutter_wait("rcu_torture_reader");
832 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
833 VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
834 rcutorture_shutdown_absorb("rcu_torture_reader");
835 if (irqreader && cur_ops->irq_capable)
837 while (!kthread_should_stop())
838 schedule_timeout_uninterruptible(1);
843 * Create an RCU-torture statistics message in the specified buffer.
846 rcu_torture_printk(char *page)
851 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
852 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
854 for_each_possible_cpu(cpu) {
855 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
856 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
857 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
860 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
861 if (pipesummary[i] != 0)
864 cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
865 cnt += sprintf(&page[cnt],
866 "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
869 rcu_torture_current_version,
870 list_empty(&rcu_torture_freelist),
871 atomic_read(&n_rcu_torture_alloc),
872 atomic_read(&n_rcu_torture_alloc_fail),
873 atomic_read(&n_rcu_torture_free),
874 atomic_read(&n_rcu_torture_mberror),
875 n_rcu_torture_timers);
876 if (atomic_read(&n_rcu_torture_mberror) != 0)
877 cnt += sprintf(&page[cnt], " !!!");
878 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
880 cnt += sprintf(&page[cnt], "!!! ");
881 atomic_inc(&n_rcu_torture_error);
884 cnt += sprintf(&page[cnt], "Reader Pipe: ");
885 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
886 cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
887 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
888 cnt += sprintf(&page[cnt], "Reader Batch: ");
889 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
890 cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
891 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
892 cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
893 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
894 cnt += sprintf(&page[cnt], " %d",
895 atomic_read(&rcu_torture_wcount[i]));
897 cnt += sprintf(&page[cnt], "\n");
899 cnt += cur_ops->stats(&page[cnt]);
904 * Print torture statistics. Caller must ensure that there is only
905 * one call to this function at a given time!!! This is normally
906 * accomplished by relying on the module system to only have one copy
907 * of the module loaded, and then by giving the rcu_torture_stats
908 * kthread full control (or the init/cleanup functions when rcu_torture_stats
909 * thread is not running).
912 rcu_torture_stats_print(void)
916 cnt = rcu_torture_printk(printk_buf);
917 printk(KERN_ALERT "%s", printk_buf);
921 * Periodically prints torture statistics, if periodic statistics printing
922 * was specified via the stat_interval module parameter.
924 * No need to worry about fullstop here, since this one doesn't reference
925 * volatile state or register callbacks.
928 rcu_torture_stats(void *arg)
930 VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
932 schedule_timeout_interruptible(stat_interval * HZ);
933 rcu_torture_stats_print();
934 rcutorture_shutdown_absorb("rcu_torture_stats");
935 } while (!kthread_should_stop());
936 VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
940 static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
942 /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
943 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
945 static void rcu_torture_shuffle_tasks(void)
949 cpumask_setall(shuffle_tmp_mask);
952 /* No point in shuffling if there is only one online CPU (ex: UP) */
953 if (num_online_cpus() == 1) {
958 if (rcu_idle_cpu != -1)
959 cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
961 set_cpus_allowed_ptr(current, shuffle_tmp_mask);
964 for (i = 0; i < nrealreaders; i++)
966 set_cpus_allowed_ptr(reader_tasks[i],
970 if (fakewriter_tasks) {
971 for (i = 0; i < nfakewriters; i++)
972 if (fakewriter_tasks[i])
973 set_cpus_allowed_ptr(fakewriter_tasks[i],
978 set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
981 set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
983 if (rcu_idle_cpu == -1)
984 rcu_idle_cpu = num_online_cpus() - 1;
991 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
992 * system to become idle at a time and cut off its timer ticks. This is meant
993 * to test the support for such tickless idle CPU in RCU.
996 rcu_torture_shuffle(void *arg)
998 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
1000 schedule_timeout_interruptible(shuffle_interval * HZ);
1001 rcu_torture_shuffle_tasks();
1002 rcutorture_shutdown_absorb("rcu_torture_shuffle");
1003 } while (!kthread_should_stop());
1004 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
1008 /* Cause the rcutorture test to "stutter", starting and stopping all
1009 * threads periodically.
1012 rcu_torture_stutter(void *arg)
1014 VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
1016 schedule_timeout_interruptible(stutter * HZ);
1017 stutter_pause_test = 1;
1018 if (!kthread_should_stop())
1019 schedule_timeout_interruptible(stutter * HZ);
1020 stutter_pause_test = 0;
1021 rcutorture_shutdown_absorb("rcu_torture_stutter");
1022 } while (!kthread_should_stop());
1023 VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
1028 rcu_torture_print_module_parms(char *tag)
1030 printk(KERN_ALERT "%s" TORTURE_FLAG
1031 "--- %s: nreaders=%d nfakewriters=%d "
1032 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1033 "shuffle_interval=%d stutter=%d irqreader=%d\n",
1034 torture_type, tag, nrealreaders, nfakewriters,
1035 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1036 stutter, irqreader);
1039 static struct notifier_block rcutorture_nb = {
1040 .notifier_call = rcutorture_shutdown_notify,
1044 rcu_torture_cleanup(void)
1048 mutex_lock(&fullstop_mutex);
1049 if (fullstop == FULLSTOP_SHUTDOWN) {
1050 printk(KERN_WARNING /* but going down anyway, so... */
1051 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
1052 mutex_unlock(&fullstop_mutex);
1053 schedule_timeout_uninterruptible(10);
1054 if (cur_ops->cb_barrier != NULL)
1055 cur_ops->cb_barrier();
1058 fullstop = FULLSTOP_RMMOD;
1059 mutex_unlock(&fullstop_mutex);
1060 unregister_reboot_notifier(&rcutorture_nb);
1062 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1063 kthread_stop(stutter_task);
1065 stutter_task = NULL;
1066 if (shuffler_task) {
1067 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1068 kthread_stop(shuffler_task);
1069 free_cpumask_var(shuffle_tmp_mask);
1071 shuffler_task = NULL;
1074 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1075 kthread_stop(writer_task);
1080 for (i = 0; i < nrealreaders; i++) {
1081 if (reader_tasks[i]) {
1082 VERBOSE_PRINTK_STRING(
1083 "Stopping rcu_torture_reader task");
1084 kthread_stop(reader_tasks[i]);
1086 reader_tasks[i] = NULL;
1088 kfree(reader_tasks);
1089 reader_tasks = NULL;
1091 rcu_torture_current = NULL;
1093 if (fakewriter_tasks) {
1094 for (i = 0; i < nfakewriters; i++) {
1095 if (fakewriter_tasks[i]) {
1096 VERBOSE_PRINTK_STRING(
1097 "Stopping rcu_torture_fakewriter task");
1098 kthread_stop(fakewriter_tasks[i]);
1100 fakewriter_tasks[i] = NULL;
1102 kfree(fakewriter_tasks);
1103 fakewriter_tasks = NULL;
1107 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1108 kthread_stop(stats_task);
1112 /* Wait for all RCU callbacks to fire. */
1114 if (cur_ops->cb_barrier != NULL)
1115 cur_ops->cb_barrier();
1117 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1119 if (cur_ops->cleanup)
1121 if (atomic_read(&n_rcu_torture_error))
1122 rcu_torture_print_module_parms("End of test: FAILURE");
1124 rcu_torture_print_module_parms("End of test: SUCCESS");
1128 rcu_torture_init(void)
1133 static struct rcu_torture_ops *torture_ops[] =
1134 { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops,
1135 &rcu_bh_ops, &rcu_bh_sync_ops,
1136 &srcu_ops, &srcu_expedited_ops,
1137 &sched_ops, &sched_sync_ops, &sched_expedited_ops, };
1139 mutex_lock(&fullstop_mutex);
1141 /* Process args and tell the world that the torturer is on the job. */
1142 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1143 cur_ops = torture_ops[i];
1144 if (strcmp(torture_type, cur_ops->name) == 0)
1147 if (i == ARRAY_SIZE(torture_ops)) {
1148 printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n",
1150 printk(KERN_ALERT "rcu-torture types:");
1151 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1152 printk(KERN_ALERT " %s", torture_ops[i]->name);
1153 printk(KERN_ALERT "\n");
1154 mutex_unlock(&fullstop_mutex);
1158 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1161 nrealreaders = nreaders;
1163 nrealreaders = 2 * num_online_cpus();
1164 rcu_torture_print_module_parms("Start of test");
1165 fullstop = FULLSTOP_DONTSTOP;
1167 /* Set up the freelist. */
1169 INIT_LIST_HEAD(&rcu_torture_freelist);
1170 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1171 rcu_tortures[i].rtort_mbtest = 0;
1172 list_add_tail(&rcu_tortures[i].rtort_free,
1173 &rcu_torture_freelist);
1176 /* Initialize the statistics so that each run gets its own numbers. */
1178 rcu_torture_current = NULL;
1179 rcu_torture_current_version = 0;
1180 atomic_set(&n_rcu_torture_alloc, 0);
1181 atomic_set(&n_rcu_torture_alloc_fail, 0);
1182 atomic_set(&n_rcu_torture_free, 0);
1183 atomic_set(&n_rcu_torture_mberror, 0);
1184 atomic_set(&n_rcu_torture_error, 0);
1185 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1186 atomic_set(&rcu_torture_wcount[i], 0);
1187 for_each_possible_cpu(cpu) {
1188 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1189 per_cpu(rcu_torture_count, cpu)[i] = 0;
1190 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1194 /* Start up the kthreads. */
1196 VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
1197 writer_task = kthread_run(rcu_torture_writer, NULL,
1198 "rcu_torture_writer");
1199 if (IS_ERR(writer_task)) {
1200 firsterr = PTR_ERR(writer_task);
1201 VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
1205 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1207 if (fakewriter_tasks == NULL) {
1208 VERBOSE_PRINTK_ERRSTRING("out of memory");
1212 for (i = 0; i < nfakewriters; i++) {
1213 VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
1214 fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
1215 "rcu_torture_fakewriter");
1216 if (IS_ERR(fakewriter_tasks[i])) {
1217 firsterr = PTR_ERR(fakewriter_tasks[i]);
1218 VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
1219 fakewriter_tasks[i] = NULL;
1223 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1225 if (reader_tasks == NULL) {
1226 VERBOSE_PRINTK_ERRSTRING("out of memory");
1230 for (i = 0; i < nrealreaders; i++) {
1231 VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
1232 reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
1233 "rcu_torture_reader");
1234 if (IS_ERR(reader_tasks[i])) {
1235 firsterr = PTR_ERR(reader_tasks[i]);
1236 VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
1237 reader_tasks[i] = NULL;
1241 if (stat_interval > 0) {
1242 VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
1243 stats_task = kthread_run(rcu_torture_stats, NULL,
1244 "rcu_torture_stats");
1245 if (IS_ERR(stats_task)) {
1246 firsterr = PTR_ERR(stats_task);
1247 VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
1252 if (test_no_idle_hz) {
1253 rcu_idle_cpu = num_online_cpus() - 1;
1255 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
1257 VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
1261 /* Create the shuffler thread */
1262 shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
1263 "rcu_torture_shuffle");
1264 if (IS_ERR(shuffler_task)) {
1265 free_cpumask_var(shuffle_tmp_mask);
1266 firsterr = PTR_ERR(shuffler_task);
1267 VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
1268 shuffler_task = NULL;
1275 /* Create the stutter thread */
1276 stutter_task = kthread_run(rcu_torture_stutter, NULL,
1277 "rcu_torture_stutter");
1278 if (IS_ERR(stutter_task)) {
1279 firsterr = PTR_ERR(stutter_task);
1280 VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
1281 stutter_task = NULL;
1285 register_reboot_notifier(&rcutorture_nb);
1286 mutex_unlock(&fullstop_mutex);
1290 mutex_unlock(&fullstop_mutex);
1291 rcu_torture_cleanup();
1295 module_init(rcu_torture_init);
1296 module_exit(rcu_torture_cleanup);