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/module.h>
39 #include <linux/completion.h>
40 #include <linux/moduleparam.h>
41 #include <linux/percpu.h>
42 #include <linux/notifier.h>
43 #include <linux/cpu.h>
44 #include <linux/random.h>
45 #include <linux/delay.h>
46 #include <linux/byteorder/swabb.h>
47 #include <linux/stat.h>
48 #include <linux/srcu.h>
50 MODULE_LICENSE("GPL");
51 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and "
52 "Josh Triplett <josh@freedesktop.org>");
54 static int nreaders
= -1; /* # reader threads, defaults to 2*ncpus */
55 static int nfakewriters
= 4; /* # fake writer threads */
56 static int stat_interval
; /* Interval between stats, in seconds. */
57 /* Defaults to "only at end of test". */
58 static int verbose
; /* Print more debug info. */
59 static int test_no_idle_hz
; /* Test RCU's support for tickless idle CPUs. */
60 static int shuffle_interval
= 5; /* Interval between shuffles (in sec)*/
61 static char *torture_type
= "rcu"; /* What to torture: rcu, rcu_bh, srcu. */
63 module_param(nreaders
, int, 0);
64 MODULE_PARM_DESC(nreaders
, "Number of RCU reader threads");
65 module_param(nfakewriters
, int, 0);
66 MODULE_PARM_DESC(nfakewriters
, "Number of RCU fake writer threads");
67 module_param(stat_interval
, int, 0);
68 MODULE_PARM_DESC(stat_interval
, "Number of seconds between stats printk()s");
69 module_param(verbose
, bool, 0);
70 MODULE_PARM_DESC(verbose
, "Enable verbose debugging printk()s");
71 module_param(test_no_idle_hz
, bool, 0);
72 MODULE_PARM_DESC(test_no_idle_hz
, "Test support for tickless idle CPUs");
73 module_param(shuffle_interval
, int, 0);
74 MODULE_PARM_DESC(shuffle_interval
, "Number of seconds between shuffles");
75 module_param(torture_type
, charp
, 0);
76 MODULE_PARM_DESC(torture_type
, "Type of RCU to torture (rcu, rcu_bh, srcu)");
78 #define TORTURE_FLAG "-torture:"
79 #define PRINTK_STRING(s) \
80 do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
81 #define VERBOSE_PRINTK_STRING(s) \
82 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
83 #define VERBOSE_PRINTK_ERRSTRING(s) \
84 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
86 static char printk_buf
[4096];
88 static int nrealreaders
;
89 static struct task_struct
*writer_task
;
90 static struct task_struct
**fakewriter_tasks
;
91 static struct task_struct
**reader_tasks
;
92 static struct task_struct
*stats_task
;
93 static struct task_struct
*shuffler_task
;
95 #define RCU_TORTURE_PIPE_LEN 10
98 struct rcu_head rtort_rcu
;
100 struct list_head rtort_free
;
104 static int fullstop
= 0; /* stop generating callbacks at test end. */
105 static LIST_HEAD(rcu_torture_freelist
);
106 static struct rcu_torture
*rcu_torture_current
= NULL
;
107 static long rcu_torture_current_version
= 0;
108 static struct rcu_torture rcu_tortures
[10 * RCU_TORTURE_PIPE_LEN
];
109 static DEFINE_SPINLOCK(rcu_torture_lock
);
110 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN
+ 1], rcu_torture_count
) =
112 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN
+ 1], rcu_torture_batch
) =
114 static atomic_t rcu_torture_wcount
[RCU_TORTURE_PIPE_LEN
+ 1];
115 static atomic_t n_rcu_torture_alloc
;
116 static atomic_t n_rcu_torture_alloc_fail
;
117 static atomic_t n_rcu_torture_free
;
118 static atomic_t n_rcu_torture_mberror
;
119 static atomic_t n_rcu_torture_error
;
120 static struct list_head rcu_torture_removed
;
123 * Allocate an element from the rcu_tortures pool.
125 static struct rcu_torture
*
126 rcu_torture_alloc(void)
130 spin_lock_bh(&rcu_torture_lock
);
131 if (list_empty(&rcu_torture_freelist
)) {
132 atomic_inc(&n_rcu_torture_alloc_fail
);
133 spin_unlock_bh(&rcu_torture_lock
);
136 atomic_inc(&n_rcu_torture_alloc
);
137 p
= rcu_torture_freelist
.next
;
139 spin_unlock_bh(&rcu_torture_lock
);
140 return container_of(p
, struct rcu_torture
, rtort_free
);
144 * Free an element to the rcu_tortures pool.
147 rcu_torture_free(struct rcu_torture
*p
)
149 atomic_inc(&n_rcu_torture_free
);
150 spin_lock_bh(&rcu_torture_lock
);
151 list_add_tail(&p
->rtort_free
, &rcu_torture_freelist
);
152 spin_unlock_bh(&rcu_torture_lock
);
155 struct rcu_random_state
{
156 unsigned long rrs_state
;
160 #define RCU_RANDOM_MULT 39916801 /* prime */
161 #define RCU_RANDOM_ADD 479001701 /* prime */
162 #define RCU_RANDOM_REFRESH 10000
164 #define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
167 * Crude but fast random-number generator. Uses a linear congruential
168 * generator, with occasional help from get_random_bytes().
171 rcu_random(struct rcu_random_state
*rrsp
)
175 if (--rrsp
->rrs_count
< 0) {
176 get_random_bytes(&refresh
, sizeof(refresh
));
177 rrsp
->rrs_state
+= refresh
;
178 rrsp
->rrs_count
= RCU_RANDOM_REFRESH
;
180 rrsp
->rrs_state
= rrsp
->rrs_state
* RCU_RANDOM_MULT
+ RCU_RANDOM_ADD
;
181 return swahw32(rrsp
->rrs_state
);
185 * Operations vector for selecting different types of tests.
188 struct rcu_torture_ops
{
190 void (*cleanup
)(void);
191 int (*readlock
)(void);
192 void (*readdelay
)(struct rcu_random_state
*rrsp
);
193 void (*readunlock
)(int idx
);
194 int (*completed
)(void);
195 void (*deferredfree
)(struct rcu_torture
*p
);
197 int (*stats
)(char *page
);
200 static struct rcu_torture_ops
*cur_ops
= NULL
;
203 * Definitions for rcu torture testing.
206 static int rcu_torture_read_lock(void) __acquires(RCU
)
212 static void rcu_read_delay(struct rcu_random_state
*rrsp
)
215 const long longdelay
= 200;
217 /* We want there to be long-running readers, but not all the time. */
219 delay
= rcu_random(rrsp
) % (nrealreaders
* 2 * longdelay
);
224 static void rcu_torture_read_unlock(int idx
) __releases(RCU
)
229 static int rcu_torture_completed(void)
231 return rcu_batches_completed();
235 rcu_torture_cb(struct rcu_head
*p
)
238 struct rcu_torture
*rp
= container_of(p
, struct rcu_torture
, rtort_rcu
);
241 /* Test is ending, just drop callbacks on the floor. */
242 /* The next initialization will pick up the pieces. */
245 i
= rp
->rtort_pipe_count
;
246 if (i
> RCU_TORTURE_PIPE_LEN
)
247 i
= RCU_TORTURE_PIPE_LEN
;
248 atomic_inc(&rcu_torture_wcount
[i
]);
249 if (++rp
->rtort_pipe_count
>= RCU_TORTURE_PIPE_LEN
) {
250 rp
->rtort_mbtest
= 0;
251 rcu_torture_free(rp
);
253 cur_ops
->deferredfree(rp
);
256 static void rcu_torture_deferred_free(struct rcu_torture
*p
)
258 call_rcu(&p
->rtort_rcu
, rcu_torture_cb
);
261 static struct rcu_torture_ops rcu_ops
= {
264 .readlock
= rcu_torture_read_lock
,
265 .readdelay
= rcu_read_delay
,
266 .readunlock
= rcu_torture_read_unlock
,
267 .completed
= rcu_torture_completed
,
268 .deferredfree
= rcu_torture_deferred_free
,
269 .sync
= synchronize_rcu
,
274 static void rcu_sync_torture_deferred_free(struct rcu_torture
*p
)
277 struct rcu_torture
*rp
;
278 struct rcu_torture
*rp1
;
281 list_add(&p
->rtort_free
, &rcu_torture_removed
);
282 list_for_each_entry_safe(rp
, rp1
, &rcu_torture_removed
, rtort_free
) {
283 i
= rp
->rtort_pipe_count
;
284 if (i
> RCU_TORTURE_PIPE_LEN
)
285 i
= RCU_TORTURE_PIPE_LEN
;
286 atomic_inc(&rcu_torture_wcount
[i
]);
287 if (++rp
->rtort_pipe_count
>= RCU_TORTURE_PIPE_LEN
) {
288 rp
->rtort_mbtest
= 0;
289 list_del(&rp
->rtort_free
);
290 rcu_torture_free(rp
);
295 static void rcu_sync_torture_init(void)
297 INIT_LIST_HEAD(&rcu_torture_removed
);
301 * Definitions for rcu_bh torture testing.
304 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH
)
310 static void rcu_bh_torture_read_unlock(int idx
) __releases(RCU_BH
)
312 rcu_read_unlock_bh();
315 static int rcu_bh_torture_completed(void)
317 return rcu_batches_completed_bh();
320 static void rcu_bh_torture_deferred_free(struct rcu_torture
*p
)
322 call_rcu_bh(&p
->rtort_rcu
, rcu_torture_cb
);
325 struct rcu_bh_torture_synchronize
{
326 struct rcu_head head
;
327 struct completion completion
;
330 static void rcu_bh_torture_wakeme_after_cb(struct rcu_head
*head
)
332 struct rcu_bh_torture_synchronize
*rcu
;
334 rcu
= container_of(head
, struct rcu_bh_torture_synchronize
, head
);
335 complete(&rcu
->completion
);
338 static void rcu_bh_torture_synchronize(void)
340 struct rcu_bh_torture_synchronize rcu
;
342 init_completion(&rcu
.completion
);
343 call_rcu_bh(&rcu
.head
, rcu_bh_torture_wakeme_after_cb
);
344 wait_for_completion(&rcu
.completion
);
347 static struct rcu_torture_ops rcu_bh_ops
= {
350 .readlock
= rcu_bh_torture_read_lock
,
351 .readdelay
= rcu_read_delay
, /* just reuse rcu's version. */
352 .readunlock
= rcu_bh_torture_read_unlock
,
353 .completed
= rcu_bh_torture_completed
,
354 .deferredfree
= rcu_bh_torture_deferred_free
,
355 .sync
= rcu_bh_torture_synchronize
,
361 * Definitions for srcu torture testing.
364 static struct srcu_struct srcu_ctl
;
366 static void srcu_torture_init(void)
368 init_srcu_struct(&srcu_ctl
);
369 rcu_sync_torture_init();
372 static void srcu_torture_cleanup(void)
374 synchronize_srcu(&srcu_ctl
);
375 cleanup_srcu_struct(&srcu_ctl
);
378 static int srcu_torture_read_lock(void)
380 return srcu_read_lock(&srcu_ctl
);
383 static void srcu_read_delay(struct rcu_random_state
*rrsp
)
386 const long uspertick
= 1000000 / HZ
;
387 const long longdelay
= 10;
389 /* We want there to be long-running readers, but not all the time. */
391 delay
= rcu_random(rrsp
) % (nrealreaders
* 2 * longdelay
* uspertick
);
393 schedule_timeout_interruptible(longdelay
);
396 static void srcu_torture_read_unlock(int idx
)
398 srcu_read_unlock(&srcu_ctl
, idx
);
401 static int srcu_torture_completed(void)
403 return srcu_batches_completed(&srcu_ctl
);
406 static void srcu_torture_synchronize(void)
408 synchronize_srcu(&srcu_ctl
);
411 static int srcu_torture_stats(char *page
)
415 int idx
= srcu_ctl
.completed
& 0x1;
417 cnt
+= sprintf(&page
[cnt
], "%s%s per-CPU(idx=%d):",
418 torture_type
, TORTURE_FLAG
, idx
);
419 for_each_possible_cpu(cpu
) {
420 cnt
+= sprintf(&page
[cnt
], " %d(%d,%d)", cpu
,
421 per_cpu_ptr(srcu_ctl
.per_cpu_ref
, cpu
)->c
[!idx
],
422 per_cpu_ptr(srcu_ctl
.per_cpu_ref
, cpu
)->c
[idx
]);
424 cnt
+= sprintf(&page
[cnt
], "\n");
428 static struct rcu_torture_ops srcu_ops
= {
429 .init
= srcu_torture_init
,
430 .cleanup
= srcu_torture_cleanup
,
431 .readlock
= srcu_torture_read_lock
,
432 .readdelay
= srcu_read_delay
,
433 .readunlock
= srcu_torture_read_unlock
,
434 .completed
= srcu_torture_completed
,
435 .deferredfree
= rcu_sync_torture_deferred_free
,
436 .sync
= srcu_torture_synchronize
,
437 .stats
= srcu_torture_stats
,
441 static struct rcu_torture_ops
*torture_ops
[] =
442 { &rcu_ops
, &rcu_bh_ops
, &srcu_ops
, NULL
};
445 * RCU torture writer kthread. Repeatedly substitutes a new structure
446 * for that pointed to by rcu_torture_current, freeing the old structure
447 * after a series of grace periods (the "pipeline").
450 rcu_torture_writer(void *arg
)
453 long oldbatch
= rcu_batches_completed();
454 struct rcu_torture
*rp
;
455 struct rcu_torture
*old_rp
;
456 static DEFINE_RCU_RANDOM(rand
);
458 VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
459 set_user_nice(current
, 19);
462 schedule_timeout_uninterruptible(1);
463 if ((rp
= rcu_torture_alloc()) == NULL
)
465 rp
->rtort_pipe_count
= 0;
466 udelay(rcu_random(&rand
) & 0x3ff);
467 old_rp
= rcu_torture_current
;
468 rp
->rtort_mbtest
= 1;
469 rcu_assign_pointer(rcu_torture_current
, rp
);
471 if (old_rp
!= NULL
) {
472 i
= old_rp
->rtort_pipe_count
;
473 if (i
> RCU_TORTURE_PIPE_LEN
)
474 i
= RCU_TORTURE_PIPE_LEN
;
475 atomic_inc(&rcu_torture_wcount
[i
]);
476 old_rp
->rtort_pipe_count
++;
477 cur_ops
->deferredfree(old_rp
);
479 rcu_torture_current_version
++;
480 oldbatch
= cur_ops
->completed();
481 } while (!kthread_should_stop() && !fullstop
);
482 VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
483 while (!kthread_should_stop())
484 schedule_timeout_uninterruptible(1);
489 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
490 * delay between calls.
493 rcu_torture_fakewriter(void *arg
)
495 DEFINE_RCU_RANDOM(rand
);
497 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
498 set_user_nice(current
, 19);
501 schedule_timeout_uninterruptible(1 + rcu_random(&rand
)%10);
502 udelay(rcu_random(&rand
) & 0x3ff);
504 } while (!kthread_should_stop() && !fullstop
);
506 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
507 while (!kthread_should_stop())
508 schedule_timeout_uninterruptible(1);
513 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
514 * incrementing the corresponding element of the pipeline array. The
515 * counter in the element should never be greater than 1, otherwise, the
516 * RCU implementation is broken.
519 rcu_torture_reader(void *arg
)
523 DEFINE_RCU_RANDOM(rand
);
524 struct rcu_torture
*p
;
527 VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
528 set_user_nice(current
, 19);
531 idx
= cur_ops
->readlock();
532 completed
= cur_ops
->completed();
533 p
= rcu_dereference(rcu_torture_current
);
535 /* Wait for rcu_torture_writer to get underway */
536 cur_ops
->readunlock(idx
);
537 schedule_timeout_interruptible(HZ
);
540 if (p
->rtort_mbtest
== 0)
541 atomic_inc(&n_rcu_torture_mberror
);
542 cur_ops
->readdelay(&rand
);
544 pipe_count
= p
->rtort_pipe_count
;
545 if (pipe_count
> RCU_TORTURE_PIPE_LEN
) {
546 /* Should not happen, but... */
547 pipe_count
= RCU_TORTURE_PIPE_LEN
;
549 ++__get_cpu_var(rcu_torture_count
)[pipe_count
];
550 completed
= cur_ops
->completed() - completed
;
551 if (completed
> RCU_TORTURE_PIPE_LEN
) {
552 /* Should not happen, but... */
553 completed
= RCU_TORTURE_PIPE_LEN
;
555 ++__get_cpu_var(rcu_torture_batch
)[completed
];
557 cur_ops
->readunlock(idx
);
559 } while (!kthread_should_stop() && !fullstop
);
560 VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
561 while (!kthread_should_stop())
562 schedule_timeout_uninterruptible(1);
567 * Create an RCU-torture statistics message in the specified buffer.
570 rcu_torture_printk(char *page
)
575 long pipesummary
[RCU_TORTURE_PIPE_LEN
+ 1] = { 0 };
576 long batchsummary
[RCU_TORTURE_PIPE_LEN
+ 1] = { 0 };
578 for_each_possible_cpu(cpu
) {
579 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
580 pipesummary
[i
] += per_cpu(rcu_torture_count
, cpu
)[i
];
581 batchsummary
[i
] += per_cpu(rcu_torture_batch
, cpu
)[i
];
584 for (i
= RCU_TORTURE_PIPE_LEN
- 1; i
>= 0; i
--) {
585 if (pipesummary
[i
] != 0)
588 cnt
+= sprintf(&page
[cnt
], "%s%s ", torture_type
, TORTURE_FLAG
);
589 cnt
+= sprintf(&page
[cnt
],
590 "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
593 rcu_torture_current_version
,
594 list_empty(&rcu_torture_freelist
),
595 atomic_read(&n_rcu_torture_alloc
),
596 atomic_read(&n_rcu_torture_alloc_fail
),
597 atomic_read(&n_rcu_torture_free
),
598 atomic_read(&n_rcu_torture_mberror
));
599 if (atomic_read(&n_rcu_torture_mberror
) != 0)
600 cnt
+= sprintf(&page
[cnt
], " !!!");
601 cnt
+= sprintf(&page
[cnt
], "\n%s%s ", torture_type
, TORTURE_FLAG
);
603 cnt
+= sprintf(&page
[cnt
], "!!! ");
604 atomic_inc(&n_rcu_torture_error
);
606 cnt
+= sprintf(&page
[cnt
], "Reader Pipe: ");
607 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
608 cnt
+= sprintf(&page
[cnt
], " %ld", pipesummary
[i
]);
609 cnt
+= sprintf(&page
[cnt
], "\n%s%s ", torture_type
, TORTURE_FLAG
);
610 cnt
+= sprintf(&page
[cnt
], "Reader Batch: ");
611 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
612 cnt
+= sprintf(&page
[cnt
], " %ld", batchsummary
[i
]);
613 cnt
+= sprintf(&page
[cnt
], "\n%s%s ", torture_type
, TORTURE_FLAG
);
614 cnt
+= sprintf(&page
[cnt
], "Free-Block Circulation: ");
615 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
616 cnt
+= sprintf(&page
[cnt
], " %d",
617 atomic_read(&rcu_torture_wcount
[i
]));
619 cnt
+= sprintf(&page
[cnt
], "\n");
620 if (cur_ops
->stats
!= NULL
)
621 cnt
+= cur_ops
->stats(&page
[cnt
]);
626 * Print torture statistics. Caller must ensure that there is only
627 * one call to this function at a given time!!! This is normally
628 * accomplished by relying on the module system to only have one copy
629 * of the module loaded, and then by giving the rcu_torture_stats
630 * kthread full control (or the init/cleanup functions when rcu_torture_stats
631 * thread is not running).
634 rcu_torture_stats_print(void)
638 cnt
= rcu_torture_printk(printk_buf
);
639 printk(KERN_ALERT
"%s", printk_buf
);
643 * Periodically prints torture statistics, if periodic statistics printing
644 * was specified via the stat_interval module parameter.
646 * No need to worry about fullstop here, since this one doesn't reference
647 * volatile state or register callbacks.
650 rcu_torture_stats(void *arg
)
652 VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
654 schedule_timeout_interruptible(stat_interval
* HZ
);
655 rcu_torture_stats_print();
656 } while (!kthread_should_stop());
657 VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
661 static int rcu_idle_cpu
; /* Force all torture tasks off this CPU */
663 /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
664 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
666 static void rcu_torture_shuffle_tasks(void)
668 cpumask_t tmp_mask
= CPU_MASK_ALL
;
673 /* No point in shuffling if there is only one online CPU (ex: UP) */
674 if (num_online_cpus() == 1) {
675 unlock_cpu_hotplug();
679 if (rcu_idle_cpu
!= -1)
680 cpu_clear(rcu_idle_cpu
, tmp_mask
);
682 set_cpus_allowed(current
, tmp_mask
);
684 if (reader_tasks
!= NULL
) {
685 for (i
= 0; i
< nrealreaders
; i
++)
687 set_cpus_allowed(reader_tasks
[i
], tmp_mask
);
690 if (fakewriter_tasks
!= NULL
) {
691 for (i
= 0; i
< nfakewriters
; i
++)
692 if (fakewriter_tasks
[i
])
693 set_cpus_allowed(fakewriter_tasks
[i
], tmp_mask
);
697 set_cpus_allowed(writer_task
, tmp_mask
);
700 set_cpus_allowed(stats_task
, tmp_mask
);
702 if (rcu_idle_cpu
== -1)
703 rcu_idle_cpu
= num_online_cpus() - 1;
707 unlock_cpu_hotplug();
710 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
711 * system to become idle at a time and cut off its timer ticks. This is meant
712 * to test the support for such tickless idle CPU in RCU.
715 rcu_torture_shuffle(void *arg
)
717 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
719 schedule_timeout_interruptible(shuffle_interval
* HZ
);
720 rcu_torture_shuffle_tasks();
721 } while (!kthread_should_stop());
722 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
727 rcu_torture_print_module_parms(char *tag
)
729 printk(KERN_ALERT
"%s" TORTURE_FLAG
730 "--- %s: nreaders=%d nfakewriters=%d "
731 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
732 "shuffle_interval = %d\n",
733 torture_type
, tag
, nrealreaders
, nfakewriters
,
734 stat_interval
, verbose
, test_no_idle_hz
, shuffle_interval
);
738 rcu_torture_cleanup(void)
743 if (shuffler_task
!= NULL
) {
744 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
745 kthread_stop(shuffler_task
);
747 shuffler_task
= NULL
;
749 if (writer_task
!= NULL
) {
750 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
751 kthread_stop(writer_task
);
755 if (reader_tasks
!= NULL
) {
756 for (i
= 0; i
< nrealreaders
; i
++) {
757 if (reader_tasks
[i
] != NULL
) {
758 VERBOSE_PRINTK_STRING(
759 "Stopping rcu_torture_reader task");
760 kthread_stop(reader_tasks
[i
]);
762 reader_tasks
[i
] = NULL
;
767 rcu_torture_current
= NULL
;
769 if (fakewriter_tasks
!= NULL
) {
770 for (i
= 0; i
< nfakewriters
; i
++) {
771 if (fakewriter_tasks
[i
] != NULL
) {
772 VERBOSE_PRINTK_STRING(
773 "Stopping rcu_torture_fakewriter task");
774 kthread_stop(fakewriter_tasks
[i
]);
776 fakewriter_tasks
[i
] = NULL
;
778 kfree(fakewriter_tasks
);
779 fakewriter_tasks
= NULL
;
782 if (stats_task
!= NULL
) {
783 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
784 kthread_stop(stats_task
);
788 /* Wait for all RCU callbacks to fire. */
791 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
793 if (cur_ops
->cleanup
!= NULL
)
795 if (atomic_read(&n_rcu_torture_error
))
796 rcu_torture_print_module_parms("End of test: FAILURE");
798 rcu_torture_print_module_parms("End of test: SUCCESS");
802 rcu_torture_init(void)
808 /* Process args and tell the world that the torturer is on the job. */
810 for (i
= 0; cur_ops
= torture_ops
[i
], cur_ops
!= NULL
; i
++) {
811 cur_ops
= torture_ops
[i
];
812 if (strcmp(torture_type
, cur_ops
->name
) == 0) {
816 if (cur_ops
== NULL
) {
817 printk(KERN_ALERT
"rcutorture: invalid torture type: \"%s\"\n",
821 if (cur_ops
->init
!= NULL
)
822 cur_ops
->init(); /* no "goto unwind" prior to this point!!! */
825 nrealreaders
= nreaders
;
827 nrealreaders
= 2 * num_online_cpus();
828 rcu_torture_print_module_parms("Start of test");
831 /* Set up the freelist. */
833 INIT_LIST_HEAD(&rcu_torture_freelist
);
834 for (i
= 0; i
< sizeof(rcu_tortures
) / sizeof(rcu_tortures
[0]); i
++) {
835 rcu_tortures
[i
].rtort_mbtest
= 0;
836 list_add_tail(&rcu_tortures
[i
].rtort_free
,
837 &rcu_torture_freelist
);
840 /* Initialize the statistics so that each run gets its own numbers. */
842 rcu_torture_current
= NULL
;
843 rcu_torture_current_version
= 0;
844 atomic_set(&n_rcu_torture_alloc
, 0);
845 atomic_set(&n_rcu_torture_alloc_fail
, 0);
846 atomic_set(&n_rcu_torture_free
, 0);
847 atomic_set(&n_rcu_torture_mberror
, 0);
848 atomic_set(&n_rcu_torture_error
, 0);
849 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++)
850 atomic_set(&rcu_torture_wcount
[i
], 0);
851 for_each_possible_cpu(cpu
) {
852 for (i
= 0; i
< RCU_TORTURE_PIPE_LEN
+ 1; i
++) {
853 per_cpu(rcu_torture_count
, cpu
)[i
] = 0;
854 per_cpu(rcu_torture_batch
, cpu
)[i
] = 0;
858 /* Start up the kthreads. */
860 VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
861 writer_task
= kthread_run(rcu_torture_writer
, NULL
,
862 "rcu_torture_writer");
863 if (IS_ERR(writer_task
)) {
864 firsterr
= PTR_ERR(writer_task
);
865 VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
869 fakewriter_tasks
= kzalloc(nfakewriters
* sizeof(fakewriter_tasks
[0]),
871 if (fakewriter_tasks
== NULL
) {
872 VERBOSE_PRINTK_ERRSTRING("out of memory");
876 for (i
= 0; i
< nfakewriters
; i
++) {
877 VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
878 fakewriter_tasks
[i
] = kthread_run(rcu_torture_fakewriter
, NULL
,
879 "rcu_torture_fakewriter");
880 if (IS_ERR(fakewriter_tasks
[i
])) {
881 firsterr
= PTR_ERR(fakewriter_tasks
[i
]);
882 VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
883 fakewriter_tasks
[i
] = NULL
;
887 reader_tasks
= kzalloc(nrealreaders
* sizeof(reader_tasks
[0]),
889 if (reader_tasks
== NULL
) {
890 VERBOSE_PRINTK_ERRSTRING("out of memory");
894 for (i
= 0; i
< nrealreaders
; i
++) {
895 VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
896 reader_tasks
[i
] = kthread_run(rcu_torture_reader
, NULL
,
897 "rcu_torture_reader");
898 if (IS_ERR(reader_tasks
[i
])) {
899 firsterr
= PTR_ERR(reader_tasks
[i
]);
900 VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
901 reader_tasks
[i
] = NULL
;
905 if (stat_interval
> 0) {
906 VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
907 stats_task
= kthread_run(rcu_torture_stats
, NULL
,
908 "rcu_torture_stats");
909 if (IS_ERR(stats_task
)) {
910 firsterr
= PTR_ERR(stats_task
);
911 VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
916 if (test_no_idle_hz
) {
917 rcu_idle_cpu
= num_online_cpus() - 1;
918 /* Create the shuffler thread */
919 shuffler_task
= kthread_run(rcu_torture_shuffle
, NULL
,
920 "rcu_torture_shuffle");
921 if (IS_ERR(shuffler_task
)) {
922 firsterr
= PTR_ERR(shuffler_task
);
923 VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
924 shuffler_task
= NULL
;
931 rcu_torture_cleanup();
935 module_init(rcu_torture_init
);
936 module_exit(rcu_torture_cleanup
);