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 void rcu_torture_deferred_free(struct rcu_torture
*p
)
332 call_rcu(&p
->rtort_rcu
, rcu_torture_cb
);
335 static struct rcu_torture_ops rcu_ops
= {
338 .readlock
= rcu_torture_read_lock
,
339 .read_delay
= rcu_read_delay
,
340 .readunlock
= rcu_torture_read_unlock
,
341 .completed
= rcu_torture_completed
,
342 .deferred_free
= rcu_torture_deferred_free
,
343 .sync
= synchronize_rcu
,
344 .cb_barrier
= rcu_barrier
,
350 static void rcu_sync_torture_deferred_free(struct rcu_torture
*p
)
353 struct rcu_torture
*rp
;
354 struct rcu_torture
*rp1
;
357 list_add(&p
->rtort_free
, &rcu_torture_removed
);
358 list_for_each_entry_safe(rp
, rp1
, &rcu_torture_removed
, rtort_free
) {
359 i
= rp
->rtort_pipe_count
;
360 if (i
> RCU_TORTURE_PIPE_LEN
)
361 i
= RCU_TORTURE_PIPE_LEN
;
362 atomic_inc(&rcu_torture_wcount
[i
]);
363 if (++rp
->rtort_pipe_count
>= RCU_TORTURE_PIPE_LEN
) {
364 rp
->rtort_mbtest
= 0;
365 list_del(&rp
->rtort_free
);
366 rcu_torture_free(rp
);
371 static void rcu_sync_torture_init(void)
373 INIT_LIST_HEAD(&rcu_torture_removed
);
376 static struct rcu_torture_ops rcu_sync_ops
= {
377 .init
= rcu_sync_torture_init
,
379 .readlock
= rcu_torture_read_lock
,
380 .read_delay
= rcu_read_delay
,
381 .readunlock
= rcu_torture_read_unlock
,
382 .completed
= rcu_torture_completed
,
383 .deferred_free
= rcu_sync_torture_deferred_free
,
384 .sync
= synchronize_rcu
,
392 * Definitions for rcu_bh torture testing.
395 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH
)
401 static void rcu_bh_torture_read_unlock(int idx
) __releases(RCU_BH
)
403 rcu_read_unlock_bh();
406 static int rcu_bh_torture_completed(void)
408 return rcu_batches_completed_bh();
411 static void rcu_bh_torture_deferred_free(struct rcu_torture
*p
)
413 call_rcu_bh(&p
->rtort_rcu
, rcu_torture_cb
);
416 struct rcu_bh_torture_synchronize
{
417 struct rcu_head head
;
418 struct completion completion
;
421 static void rcu_bh_torture_wakeme_after_cb(struct rcu_head
*head
)
423 struct rcu_bh_torture_synchronize
*rcu
;
425 rcu
= container_of(head
, struct rcu_bh_torture_synchronize
, head
);
426 complete(&rcu
->completion
);
429 static void rcu_bh_torture_synchronize(void)
431 struct rcu_bh_torture_synchronize rcu
;
433 init_completion(&rcu
.completion
);
434 call_rcu_bh(&rcu
.head
, rcu_bh_torture_wakeme_after_cb
);
435 wait_for_completion(&rcu
.completion
);
438 static struct rcu_torture_ops rcu_bh_ops
= {
441 .readlock
= rcu_bh_torture_read_lock
,
442 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
443 .readunlock
= rcu_bh_torture_read_unlock
,
444 .completed
= rcu_bh_torture_completed
,
445 .deferred_free
= rcu_bh_torture_deferred_free
,
446 .sync
= rcu_bh_torture_synchronize
,
447 .cb_barrier
= rcu_barrier_bh
,
453 static struct rcu_torture_ops rcu_bh_sync_ops
= {
454 .init
= rcu_sync_torture_init
,
456 .readlock
= rcu_bh_torture_read_lock
,
457 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
458 .readunlock
= rcu_bh_torture_read_unlock
,
459 .completed
= rcu_bh_torture_completed
,
460 .deferred_free
= rcu_sync_torture_deferred_free
,
461 .sync
= rcu_bh_torture_synchronize
,
465 .name
= "rcu_bh_sync"
469 * Definitions for srcu torture testing.
472 static struct srcu_struct srcu_ctl
;
474 static void srcu_torture_init(void)
476 init_srcu_struct(&srcu_ctl
);
477 rcu_sync_torture_init();
480 static void srcu_torture_cleanup(void)
482 synchronize_srcu(&srcu_ctl
);
483 cleanup_srcu_struct(&srcu_ctl
);
486 static int srcu_torture_read_lock(void) __acquires(&srcu_ctl
)
488 return srcu_read_lock(&srcu_ctl
);
491 static void srcu_read_delay(struct rcu_random_state
*rrsp
)
494 const long uspertick
= 1000000 / HZ
;
495 const long longdelay
= 10;
497 /* We want there to be long-running readers, but not all the time. */
499 delay
= rcu_random(rrsp
) % (nrealreaders
* 2 * longdelay
* uspertick
);
501 schedule_timeout_interruptible(longdelay
);
504 static void srcu_torture_read_unlock(int idx
) __releases(&srcu_ctl
)
506 srcu_read_unlock(&srcu_ctl
, idx
);
509 static int srcu_torture_completed(void)
511 return srcu_batches_completed(&srcu_ctl
);
514 static void srcu_torture_synchronize(void)
516 synchronize_srcu(&srcu_ctl
);
519 static int srcu_torture_stats(char *page
)
523 int idx
= srcu_ctl
.completed
& 0x1;
525 cnt
+= sprintf(&page
[cnt
], "%s%s per-CPU(idx=%d):",
526 torture_type
, TORTURE_FLAG
, idx
);
527 for_each_possible_cpu(cpu
) {
528 cnt
+= sprintf(&page
[cnt
], " %d(%d,%d)", cpu
,
529 per_cpu_ptr(srcu_ctl
.per_cpu_ref
, cpu
)->c
[!idx
],
530 per_cpu_ptr(srcu_ctl
.per_cpu_ref
, cpu
)->c
[idx
]);
532 cnt
+= sprintf(&page
[cnt
], "\n");
536 static struct rcu_torture_ops srcu_ops
= {
537 .init
= srcu_torture_init
,
538 .cleanup
= srcu_torture_cleanup
,
539 .readlock
= srcu_torture_read_lock
,
540 .read_delay
= srcu_read_delay
,
541 .readunlock
= srcu_torture_read_unlock
,
542 .completed
= srcu_torture_completed
,
543 .deferred_free
= rcu_sync_torture_deferred_free
,
544 .sync
= srcu_torture_synchronize
,
546 .stats
= srcu_torture_stats
,
550 static void srcu_torture_synchronize_expedited(void)
552 synchronize_srcu_expedited(&srcu_ctl
);
555 static struct rcu_torture_ops srcu_expedited_ops
= {
556 .init
= srcu_torture_init
,
557 .cleanup
= srcu_torture_cleanup
,
558 .readlock
= srcu_torture_read_lock
,
559 .read_delay
= srcu_read_delay
,
560 .readunlock
= srcu_torture_read_unlock
,
561 .completed
= srcu_torture_completed
,
562 .deferred_free
= rcu_sync_torture_deferred_free
,
563 .sync
= srcu_torture_synchronize_expedited
,
565 .stats
= srcu_torture_stats
,
566 .name
= "srcu_expedited"
570 * Definitions for sched torture testing.
573 static int sched_torture_read_lock(void)
579 static void sched_torture_read_unlock(int idx
)
584 static int sched_torture_completed(void)
589 static void rcu_sched_torture_deferred_free(struct rcu_torture
*p
)
591 call_rcu_sched(&p
->rtort_rcu
, rcu_torture_cb
);
594 static void sched_torture_synchronize(void)
599 static struct rcu_torture_ops sched_ops
= {
600 .init
= rcu_sync_torture_init
,
602 .readlock
= sched_torture_read_lock
,
603 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
604 .readunlock
= sched_torture_read_unlock
,
605 .completed
= sched_torture_completed
,
606 .deferred_free
= rcu_sched_torture_deferred_free
,
607 .sync
= sched_torture_synchronize
,
608 .cb_barrier
= rcu_barrier_sched
,
614 static struct rcu_torture_ops sched_sync_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
= sched_torture_completed
,
621 .deferred_free
= rcu_sync_torture_deferred_free
,
622 .sync
= sched_torture_synchronize
,
628 static struct rcu_torture_ops sched_expedited_ops
= {
629 .init
= rcu_sync_torture_init
,
631 .readlock
= sched_torture_read_lock
,
632 .read_delay
= rcu_read_delay
, /* just reuse rcu's version. */
633 .readunlock
= sched_torture_read_unlock
,
634 .completed
= sched_torture_completed
,
635 .deferred_free
= rcu_sync_torture_deferred_free
,
636 .sync
= synchronize_sched_expedited
,
638 .stats
= rcu_expedited_torture_stats
,
640 .name
= "sched_expedited"
644 * RCU torture writer kthread. Repeatedly substitutes a new structure
645 * for that pointed to by rcu_torture_current, freeing the old structure
646 * after a series of grace periods (the "pipeline").
649 rcu_torture_writer(void *arg
)
652 long oldbatch
= rcu_batches_completed();
653 struct rcu_torture
*rp
;
654 struct rcu_torture
*old_rp
;
655 static DEFINE_RCU_RANDOM(rand
);
657 VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
658 set_user_nice(current
, 19);
661 schedule_timeout_uninterruptible(1);
662 rp
= rcu_torture_alloc();
665 rp
->rtort_pipe_count
= 0;
666 udelay(rcu_random(&rand
) & 0x3ff);
667 old_rp
= rcu_torture_current
;
668 rp
->rtort_mbtest
= 1;
669 rcu_assign_pointer(rcu_torture_current
, rp
);
670 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
672 i
= old_rp
->rtort_pipe_count
;
673 if (i
> RCU_TORTURE_PIPE_LEN
)
674 i
= RCU_TORTURE_PIPE_LEN
;
675 atomic_inc(&rcu_torture_wcount
[i
]);
676 old_rp
->rtort_pipe_count
++;
677 cur_ops
->deferred_free(old_rp
);
679 rcu_torture_current_version
++;
680 oldbatch
= cur_ops
->completed();
681 rcu_stutter_wait("rcu_torture_writer");
682 } while (!kthread_should_stop() && fullstop
== FULLSTOP_DONTSTOP
);
683 VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
684 rcutorture_shutdown_absorb("rcu_torture_writer");
685 while (!kthread_should_stop())
686 schedule_timeout_uninterruptible(1);
691 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
692 * delay between calls.
695 rcu_torture_fakewriter(void *arg
)
697 DEFINE_RCU_RANDOM(rand
);
699 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
700 set_user_nice(current
, 19);
703 schedule_timeout_uninterruptible(1 + rcu_random(&rand
)%10);
704 udelay(rcu_random(&rand
) & 0x3ff);
706 rcu_stutter_wait("rcu_torture_fakewriter");
707 } while (!kthread_should_stop() && fullstop
== FULLSTOP_DONTSTOP
);
709 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
710 rcutorture_shutdown_absorb("rcu_torture_fakewriter");
711 while (!kthread_should_stop())
712 schedule_timeout_uninterruptible(1);
717 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
718 * incrementing the corresponding element of the pipeline array. The
719 * counter in the element should never be greater than 1, otherwise, the
720 * RCU implementation is broken.
722 static void rcu_torture_timer(unsigned long unused
)
726 static DEFINE_RCU_RANDOM(rand
);
727 static DEFINE_SPINLOCK(rand_lock
);
728 struct rcu_torture
*p
;
731 idx
= cur_ops
->readlock();
732 completed
= cur_ops
->completed();
733 p
= rcu_dereference(rcu_torture_current
);
735 /* Leave because rcu_torture_writer is not yet underway */
736 cur_ops
->readunlock(idx
);
739 if (p
->rtort_mbtest
== 0)
740 atomic_inc(&n_rcu_torture_mberror
);
741 spin_lock(&rand_lock
);
742 cur_ops
->read_delay(&rand
);
743 n_rcu_torture_timers
++;
744 spin_unlock(&rand_lock
);
746 pipe_count
= p
->rtort_pipe_count
;
747 if (pipe_count
> RCU_TORTURE_PIPE_LEN
) {
748 /* Should not happen, but... */
749 pipe_count
= RCU_TORTURE_PIPE_LEN
;
751 ++__get_cpu_var(rcu_torture_count
)[pipe_count
];
752 completed
= cur_ops
->completed() - completed
;
753 if (completed
> RCU_TORTURE_PIPE_LEN
) {
754 /* Should not happen, but... */
755 completed
= RCU_TORTURE_PIPE_LEN
;
757 ++__get_cpu_var(rcu_torture_batch
)[completed
];
759 cur_ops
->readunlock(idx
);
763 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
764 * incrementing the corresponding element of the pipeline array. The
765 * counter in the element should never be greater than 1, otherwise, the
766 * RCU implementation is broken.
769 rcu_torture_reader(void *arg
)
773 DEFINE_RCU_RANDOM(rand
);
774 struct rcu_torture
*p
;
778 VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
779 set_user_nice(current
, 19);
780 if (irqreader
&& cur_ops
->irq_capable
)
781 setup_timer_on_stack(&t
, rcu_torture_timer
, 0);
784 if (irqreader
&& cur_ops
->irq_capable
) {
785 if (!timer_pending(&t
))
788 idx
= cur_ops
->readlock();
789 completed
= cur_ops
->completed();
790 p
= rcu_dereference(rcu_torture_current
);
792 /* Wait for rcu_torture_writer to get underway */
793 cur_ops
->readunlock(idx
);
794 schedule_timeout_interruptible(HZ
);
797 if (p
->rtort_mbtest
== 0)
798 atomic_inc(&n_rcu_torture_mberror
);
799 cur_ops
->read_delay(&rand
);
801 pipe_count
= p
->rtort_pipe_count
;
802 if (pipe_count
> RCU_TORTURE_PIPE_LEN
) {
803 /* Should not happen, but... */
804 pipe_count
= RCU_TORTURE_PIPE_LEN
;
806 ++__get_cpu_var(rcu_torture_count
)[pipe_count
];
807 completed
= cur_ops
->completed() - completed
;
808 if (completed
> RCU_TORTURE_PIPE_LEN
) {
809 /* Should not happen, but... */
810 completed
= RCU_TORTURE_PIPE_LEN
;
812 ++__get_cpu_var(rcu_torture_batch
)[completed
];
814 cur_ops
->readunlock(idx
);
816 rcu_stutter_wait("rcu_torture_reader");
817 } while (!kthread_should_stop() && fullstop
== FULLSTOP_DONTSTOP
);
818 VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
819 rcutorture_shutdown_absorb("rcu_torture_reader");
820 if (irqreader
&& cur_ops
->irq_capable
)
822 while (!kthread_should_stop())
823 schedule_timeout_uninterruptible(1);
828 * Create an RCU-torture statistics message in the specified buffer.
831 rcu_torture_printk(char *page
)
836 long pipesummary
[RCU_TORTURE_PIPE_LEN
+ 1] = { 0 };
837 long batchsummary
[RCU_TORTURE_PIPE_LEN
+ 1] = { 0 };
839 for_each_possible_cpu(cpu
) {
840 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
841 pipesummary
[i
] += per_cpu(rcu_torture_count
, cpu
)[i
];
842 batchsummary
[i
] += per_cpu(rcu_torture_batch
, cpu
)[i
];
845 for (i
= RCU_TORTURE_PIPE_LEN
- 1; i
>= 0; i
--) {
846 if (pipesummary
[i
] != 0)
849 cnt
+= sprintf(&page
[cnt
], "%s%s ", torture_type
, TORTURE_FLAG
);
850 cnt
+= sprintf(&page
[cnt
],
851 "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
854 rcu_torture_current_version
,
855 list_empty(&rcu_torture_freelist
),
856 atomic_read(&n_rcu_torture_alloc
),
857 atomic_read(&n_rcu_torture_alloc_fail
),
858 atomic_read(&n_rcu_torture_free
),
859 atomic_read(&n_rcu_torture_mberror
),
860 n_rcu_torture_timers
);
861 if (atomic_read(&n_rcu_torture_mberror
) != 0)
862 cnt
+= sprintf(&page
[cnt
], " !!!");
863 cnt
+= sprintf(&page
[cnt
], "\n%s%s ", torture_type
, TORTURE_FLAG
);
865 cnt
+= sprintf(&page
[cnt
], "!!! ");
866 atomic_inc(&n_rcu_torture_error
);
869 cnt
+= sprintf(&page
[cnt
], "Reader Pipe: ");
870 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
871 cnt
+= sprintf(&page
[cnt
], " %ld", pipesummary
[i
]);
872 cnt
+= sprintf(&page
[cnt
], "\n%s%s ", torture_type
, TORTURE_FLAG
);
873 cnt
+= sprintf(&page
[cnt
], "Reader Batch: ");
874 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
875 cnt
+= sprintf(&page
[cnt
], " %ld", batchsummary
[i
]);
876 cnt
+= sprintf(&page
[cnt
], "\n%s%s ", torture_type
, TORTURE_FLAG
);
877 cnt
+= sprintf(&page
[cnt
], "Free-Block Circulation: ");
878 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
879 cnt
+= sprintf(&page
[cnt
], " %d",
880 atomic_read(&rcu_torture_wcount
[i
]));
882 cnt
+= sprintf(&page
[cnt
], "\n");
884 cnt
+= cur_ops
->stats(&page
[cnt
]);
889 * Print torture statistics. Caller must ensure that there is only
890 * one call to this function at a given time!!! This is normally
891 * accomplished by relying on the module system to only have one copy
892 * of the module loaded, and then by giving the rcu_torture_stats
893 * kthread full control (or the init/cleanup functions when rcu_torture_stats
894 * thread is not running).
897 rcu_torture_stats_print(void)
901 cnt
= rcu_torture_printk(printk_buf
);
902 printk(KERN_ALERT
"%s", printk_buf
);
906 * Periodically prints torture statistics, if periodic statistics printing
907 * was specified via the stat_interval module parameter.
909 * No need to worry about fullstop here, since this one doesn't reference
910 * volatile state or register callbacks.
913 rcu_torture_stats(void *arg
)
915 VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
917 schedule_timeout_interruptible(stat_interval
* HZ
);
918 rcu_torture_stats_print();
919 rcutorture_shutdown_absorb("rcu_torture_stats");
920 } while (!kthread_should_stop());
921 VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
925 static int rcu_idle_cpu
; /* Force all torture tasks off this CPU */
927 /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
928 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
930 static void rcu_torture_shuffle_tasks(void)
934 cpumask_setall(shuffle_tmp_mask
);
937 /* No point in shuffling if there is only one online CPU (ex: UP) */
938 if (num_online_cpus() == 1) {
943 if (rcu_idle_cpu
!= -1)
944 cpumask_clear_cpu(rcu_idle_cpu
, shuffle_tmp_mask
);
946 set_cpus_allowed_ptr(current
, shuffle_tmp_mask
);
949 for (i
= 0; i
< nrealreaders
; i
++)
951 set_cpus_allowed_ptr(reader_tasks
[i
],
955 if (fakewriter_tasks
) {
956 for (i
= 0; i
< nfakewriters
; i
++)
957 if (fakewriter_tasks
[i
])
958 set_cpus_allowed_ptr(fakewriter_tasks
[i
],
963 set_cpus_allowed_ptr(writer_task
, shuffle_tmp_mask
);
966 set_cpus_allowed_ptr(stats_task
, shuffle_tmp_mask
);
968 if (rcu_idle_cpu
== -1)
969 rcu_idle_cpu
= num_online_cpus() - 1;
976 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
977 * system to become idle at a time and cut off its timer ticks. This is meant
978 * to test the support for such tickless idle CPU in RCU.
981 rcu_torture_shuffle(void *arg
)
983 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
985 schedule_timeout_interruptible(shuffle_interval
* HZ
);
986 rcu_torture_shuffle_tasks();
987 rcutorture_shutdown_absorb("rcu_torture_shuffle");
988 } while (!kthread_should_stop());
989 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
993 /* Cause the rcutorture test to "stutter", starting and stopping all
994 * threads periodically.
997 rcu_torture_stutter(void *arg
)
999 VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
1001 schedule_timeout_interruptible(stutter
* HZ
);
1002 stutter_pause_test
= 1;
1003 if (!kthread_should_stop())
1004 schedule_timeout_interruptible(stutter
* HZ
);
1005 stutter_pause_test
= 0;
1006 rcutorture_shutdown_absorb("rcu_torture_stutter");
1007 } while (!kthread_should_stop());
1008 VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
1013 rcu_torture_print_module_parms(char *tag
)
1015 printk(KERN_ALERT
"%s" TORTURE_FLAG
1016 "--- %s: nreaders=%d nfakewriters=%d "
1017 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1018 "shuffle_interval=%d stutter=%d irqreader=%d\n",
1019 torture_type
, tag
, nrealreaders
, nfakewriters
,
1020 stat_interval
, verbose
, test_no_idle_hz
, shuffle_interval
,
1021 stutter
, irqreader
);
1024 static struct notifier_block rcutorture_nb
= {
1025 .notifier_call
= rcutorture_shutdown_notify
,
1029 rcu_torture_cleanup(void)
1033 mutex_lock(&fullstop_mutex
);
1034 if (fullstop
== FULLSTOP_SHUTDOWN
) {
1035 printk(KERN_WARNING
/* but going down anyway, so... */
1036 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
1037 mutex_unlock(&fullstop_mutex
);
1038 schedule_timeout_uninterruptible(10);
1039 if (cur_ops
->cb_barrier
!= NULL
)
1040 cur_ops
->cb_barrier();
1043 fullstop
= FULLSTOP_RMMOD
;
1044 mutex_unlock(&fullstop_mutex
);
1045 unregister_reboot_notifier(&rcutorture_nb
);
1047 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1048 kthread_stop(stutter_task
);
1050 stutter_task
= NULL
;
1051 if (shuffler_task
) {
1052 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1053 kthread_stop(shuffler_task
);
1054 free_cpumask_var(shuffle_tmp_mask
);
1056 shuffler_task
= NULL
;
1059 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1060 kthread_stop(writer_task
);
1065 for (i
= 0; i
< nrealreaders
; i
++) {
1066 if (reader_tasks
[i
]) {
1067 VERBOSE_PRINTK_STRING(
1068 "Stopping rcu_torture_reader task");
1069 kthread_stop(reader_tasks
[i
]);
1071 reader_tasks
[i
] = NULL
;
1073 kfree(reader_tasks
);
1074 reader_tasks
= NULL
;
1076 rcu_torture_current
= NULL
;
1078 if (fakewriter_tasks
) {
1079 for (i
= 0; i
< nfakewriters
; i
++) {
1080 if (fakewriter_tasks
[i
]) {
1081 VERBOSE_PRINTK_STRING(
1082 "Stopping rcu_torture_fakewriter task");
1083 kthread_stop(fakewriter_tasks
[i
]);
1085 fakewriter_tasks
[i
] = NULL
;
1087 kfree(fakewriter_tasks
);
1088 fakewriter_tasks
= NULL
;
1092 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1093 kthread_stop(stats_task
);
1097 /* Wait for all RCU callbacks to fire. */
1099 if (cur_ops
->cb_barrier
!= NULL
)
1100 cur_ops
->cb_barrier();
1102 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1104 if (cur_ops
->cleanup
)
1106 if (atomic_read(&n_rcu_torture_error
))
1107 rcu_torture_print_module_parms("End of test: FAILURE");
1109 rcu_torture_print_module_parms("End of test: SUCCESS");
1113 rcu_torture_init(void)
1118 static struct rcu_torture_ops
*torture_ops
[] =
1119 { &rcu_ops
, &rcu_sync_ops
, &rcu_bh_ops
, &rcu_bh_sync_ops
,
1120 &srcu_ops
, &srcu_expedited_ops
,
1121 &sched_ops
, &sched_sync_ops
, &sched_expedited_ops
, };
1123 mutex_lock(&fullstop_mutex
);
1125 /* Process args and tell the world that the torturer is on the job. */
1126 for (i
= 0; i
< ARRAY_SIZE(torture_ops
); i
++) {
1127 cur_ops
= torture_ops
[i
];
1128 if (strcmp(torture_type
, cur_ops
->name
) == 0)
1131 if (i
== ARRAY_SIZE(torture_ops
)) {
1132 printk(KERN_ALERT
"rcu-torture: invalid torture type: \"%s\"\n",
1134 printk(KERN_ALERT
"rcu-torture types:");
1135 for (i
= 0; i
< ARRAY_SIZE(torture_ops
); i
++)
1136 printk(KERN_ALERT
" %s", torture_ops
[i
]->name
);
1137 printk(KERN_ALERT
"\n");
1138 mutex_unlock(&fullstop_mutex
);
1142 cur_ops
->init(); /* no "goto unwind" prior to this point!!! */
1145 nrealreaders
= nreaders
;
1147 nrealreaders
= 2 * num_online_cpus();
1148 rcu_torture_print_module_parms("Start of test");
1149 fullstop
= FULLSTOP_DONTSTOP
;
1151 /* Set up the freelist. */
1153 INIT_LIST_HEAD(&rcu_torture_freelist
);
1154 for (i
= 0; i
< ARRAY_SIZE(rcu_tortures
); i
++) {
1155 rcu_tortures
[i
].rtort_mbtest
= 0;
1156 list_add_tail(&rcu_tortures
[i
].rtort_free
,
1157 &rcu_torture_freelist
);
1160 /* Initialize the statistics so that each run gets its own numbers. */
1162 rcu_torture_current
= NULL
;
1163 rcu_torture_current_version
= 0;
1164 atomic_set(&n_rcu_torture_alloc
, 0);
1165 atomic_set(&n_rcu_torture_alloc_fail
, 0);
1166 atomic_set(&n_rcu_torture_free
, 0);
1167 atomic_set(&n_rcu_torture_mberror
, 0);
1168 atomic_set(&n_rcu_torture_error
, 0);
1169 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
1170 atomic_set(&rcu_torture_wcount
[i
], 0);
1171 for_each_possible_cpu(cpu
) {
1172 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
1173 per_cpu(rcu_torture_count
, cpu
)[i
] = 0;
1174 per_cpu(rcu_torture_batch
, cpu
)[i
] = 0;
1178 /* Start up the kthreads. */
1180 VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
1181 writer_task
= kthread_run(rcu_torture_writer
, NULL
,
1182 "rcu_torture_writer");
1183 if (IS_ERR(writer_task
)) {
1184 firsterr
= PTR_ERR(writer_task
);
1185 VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
1189 fakewriter_tasks
= kzalloc(nfakewriters
* sizeof(fakewriter_tasks
[0]),
1191 if (fakewriter_tasks
== NULL
) {
1192 VERBOSE_PRINTK_ERRSTRING("out of memory");
1196 for (i
= 0; i
< nfakewriters
; i
++) {
1197 VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
1198 fakewriter_tasks
[i
] = kthread_run(rcu_torture_fakewriter
, NULL
,
1199 "rcu_torture_fakewriter");
1200 if (IS_ERR(fakewriter_tasks
[i
])) {
1201 firsterr
= PTR_ERR(fakewriter_tasks
[i
]);
1202 VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
1203 fakewriter_tasks
[i
] = NULL
;
1207 reader_tasks
= kzalloc(nrealreaders
* sizeof(reader_tasks
[0]),
1209 if (reader_tasks
== NULL
) {
1210 VERBOSE_PRINTK_ERRSTRING("out of memory");
1214 for (i
= 0; i
< nrealreaders
; i
++) {
1215 VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
1216 reader_tasks
[i
] = kthread_run(rcu_torture_reader
, NULL
,
1217 "rcu_torture_reader");
1218 if (IS_ERR(reader_tasks
[i
])) {
1219 firsterr
= PTR_ERR(reader_tasks
[i
]);
1220 VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
1221 reader_tasks
[i
] = NULL
;
1225 if (stat_interval
> 0) {
1226 VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
1227 stats_task
= kthread_run(rcu_torture_stats
, NULL
,
1228 "rcu_torture_stats");
1229 if (IS_ERR(stats_task
)) {
1230 firsterr
= PTR_ERR(stats_task
);
1231 VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
1236 if (test_no_idle_hz
) {
1237 rcu_idle_cpu
= num_online_cpus() - 1;
1239 if (!alloc_cpumask_var(&shuffle_tmp_mask
, GFP_KERNEL
)) {
1241 VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
1245 /* Create the shuffler thread */
1246 shuffler_task
= kthread_run(rcu_torture_shuffle
, NULL
,
1247 "rcu_torture_shuffle");
1248 if (IS_ERR(shuffler_task
)) {
1249 free_cpumask_var(shuffle_tmp_mask
);
1250 firsterr
= PTR_ERR(shuffler_task
);
1251 VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
1252 shuffler_task
= NULL
;
1259 /* Create the stutter thread */
1260 stutter_task
= kthread_run(rcu_torture_stutter
, NULL
,
1261 "rcu_torture_stutter");
1262 if (IS_ERR(stutter_task
)) {
1263 firsterr
= PTR_ERR(stutter_task
);
1264 VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
1265 stutter_task
= NULL
;
1269 register_reboot_notifier(&rcutorture_nb
);
1270 mutex_unlock(&fullstop_mutex
);
1274 mutex_unlock(&fullstop_mutex
);
1275 rcu_torture_cleanup();
1279 module_init(rcu_torture_init
);
1280 module_exit(rcu_torture_cleanup
);