Loading...
Note: File does not exist in v6.13.7.
1/*
2 * Read-Copy Update module-based torture test facility
3 *
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.
8 *
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.
13 *
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.
17 *
18 * Copyright (C) IBM Corporation, 2005, 2006
19 *
20 * Authors: Paul E. McKenney <paulmck@us.ibm.com>
21 * Josh Triplett <josh@freedesktop.org>
22 *
23 * See also: Documentation/RCU/torture.txt
24 */
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 <linux/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>
50
51MODULE_LICENSE("GPL");
52MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and "
53 "Josh Triplett <josh@freedesktop.org>");
54
55static int nreaders = -1; /* # reader threads, defaults to 2*ncpus */
56static int nfakewriters = 4; /* # fake writer threads */
57static int stat_interval; /* Interval between stats, in seconds. */
58 /* Defaults to "only at end of test". */
59static int verbose; /* Print more debug info. */
60static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */
61static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/
62static int stutter = 5; /* Start/stop testing interval (in sec) */
63static int irqreader = 1; /* RCU readers from irq (timers). */
64static int fqs_duration = 0; /* Duration of bursts (us), 0 to disable. */
65static int fqs_holdoff = 0; /* Hold time within burst (us). */
66static int fqs_stutter = 3; /* Wait time between bursts (s). */
67static int test_boost = 1; /* Test RCU prio boost: 0=no, 1=maybe, 2=yes. */
68static int test_boost_interval = 7; /* Interval between boost tests, seconds. */
69static int test_boost_duration = 4; /* Duration of each boost test, seconds. */
70static char *torture_type = "rcu"; /* What RCU implementation to torture. */
71
72module_param(nreaders, int, 0444);
73MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
74module_param(nfakewriters, int, 0444);
75MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
76module_param(stat_interval, int, 0444);
77MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
78module_param(verbose, bool, 0444);
79MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
80module_param(test_no_idle_hz, bool, 0444);
81MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
82module_param(shuffle_interval, int, 0444);
83MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
84module_param(stutter, int, 0444);
85MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
86module_param(irqreader, int, 0444);
87MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
88module_param(fqs_duration, int, 0444);
89MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us)");
90module_param(fqs_holdoff, int, 0444);
91MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)");
92module_param(fqs_stutter, int, 0444);
93MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
94module_param(test_boost, int, 0444);
95MODULE_PARM_DESC(test_boost, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
96module_param(test_boost_interval, int, 0444);
97MODULE_PARM_DESC(test_boost_interval, "Interval between boost tests, seconds.");
98module_param(test_boost_duration, int, 0444);
99MODULE_PARM_DESC(test_boost_duration, "Duration of each boost test, seconds.");
100module_param(torture_type, charp, 0444);
101MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
102
103#define TORTURE_FLAG "-torture:"
104#define PRINTK_STRING(s) \
105 do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
106#define VERBOSE_PRINTK_STRING(s) \
107 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
108#define VERBOSE_PRINTK_ERRSTRING(s) \
109 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
110
111static char printk_buf[4096];
112
113static int nrealreaders;
114static struct task_struct *writer_task;
115static struct task_struct **fakewriter_tasks;
116static struct task_struct **reader_tasks;
117static struct task_struct *stats_task;
118static struct task_struct *shuffler_task;
119static struct task_struct *stutter_task;
120static struct task_struct *fqs_task;
121static struct task_struct *boost_tasks[NR_CPUS];
122
123#define RCU_TORTURE_PIPE_LEN 10
124
125struct rcu_torture {
126 struct rcu_head rtort_rcu;
127 int rtort_pipe_count;
128 struct list_head rtort_free;
129 int rtort_mbtest;
130};
131
132static LIST_HEAD(rcu_torture_freelist);
133static struct rcu_torture __rcu *rcu_torture_current;
134static unsigned long rcu_torture_current_version;
135static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
136static DEFINE_SPINLOCK(rcu_torture_lock);
137static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
138 { 0 };
139static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
140 { 0 };
141static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
142static atomic_t n_rcu_torture_alloc;
143static atomic_t n_rcu_torture_alloc_fail;
144static atomic_t n_rcu_torture_free;
145static atomic_t n_rcu_torture_mberror;
146static atomic_t n_rcu_torture_error;
147static long n_rcu_torture_boost_ktrerror;
148static long n_rcu_torture_boost_rterror;
149static long n_rcu_torture_boost_failure;
150static long n_rcu_torture_boosts;
151static long n_rcu_torture_timers;
152static struct list_head rcu_torture_removed;
153static cpumask_var_t shuffle_tmp_mask;
154
155static int stutter_pause_test;
156
157#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
158#define RCUTORTURE_RUNNABLE_INIT 1
159#else
160#define RCUTORTURE_RUNNABLE_INIT 0
161#endif
162int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
163
164#if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
165#define rcu_can_boost() 1
166#else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
167#define rcu_can_boost() 0
168#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
169
170static unsigned long boost_starttime; /* jiffies of next boost test start. */
171DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
172 /* and boost task create/destroy. */
173
174/* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
175
176#define FULLSTOP_DONTSTOP 0 /* Normal operation. */
177#define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */
178#define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */
179static int fullstop = FULLSTOP_RMMOD;
180/*
181 * Protect fullstop transitions and spawning of kthreads.
182 */
183static DEFINE_MUTEX(fullstop_mutex);
184
185/*
186 * Detect and respond to a system shutdown.
187 */
188static int
189rcutorture_shutdown_notify(struct notifier_block *unused1,
190 unsigned long unused2, void *unused3)
191{
192 mutex_lock(&fullstop_mutex);
193 if (fullstop == FULLSTOP_DONTSTOP)
194 fullstop = FULLSTOP_SHUTDOWN;
195 else
196 printk(KERN_WARNING /* but going down anyway, so... */
197 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
198 mutex_unlock(&fullstop_mutex);
199 return NOTIFY_DONE;
200}
201
202/*
203 * Absorb kthreads into a kernel function that won't return, so that
204 * they won't ever access module text or data again.
205 */
206static void rcutorture_shutdown_absorb(char *title)
207{
208 if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
209 printk(KERN_NOTICE
210 "rcutorture thread %s parking due to system shutdown\n",
211 title);
212 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
213 }
214}
215
216/*
217 * Allocate an element from the rcu_tortures pool.
218 */
219static struct rcu_torture *
220rcu_torture_alloc(void)
221{
222 struct list_head *p;
223
224 spin_lock_bh(&rcu_torture_lock);
225 if (list_empty(&rcu_torture_freelist)) {
226 atomic_inc(&n_rcu_torture_alloc_fail);
227 spin_unlock_bh(&rcu_torture_lock);
228 return NULL;
229 }
230 atomic_inc(&n_rcu_torture_alloc);
231 p = rcu_torture_freelist.next;
232 list_del_init(p);
233 spin_unlock_bh(&rcu_torture_lock);
234 return container_of(p, struct rcu_torture, rtort_free);
235}
236
237/*
238 * Free an element to the rcu_tortures pool.
239 */
240static void
241rcu_torture_free(struct rcu_torture *p)
242{
243 atomic_inc(&n_rcu_torture_free);
244 spin_lock_bh(&rcu_torture_lock);
245 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
246 spin_unlock_bh(&rcu_torture_lock);
247}
248
249struct rcu_random_state {
250 unsigned long rrs_state;
251 long rrs_count;
252};
253
254#define RCU_RANDOM_MULT 39916801 /* prime */
255#define RCU_RANDOM_ADD 479001701 /* prime */
256#define RCU_RANDOM_REFRESH 10000
257
258#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
259
260/*
261 * Crude but fast random-number generator. Uses a linear congruential
262 * generator, with occasional help from cpu_clock().
263 */
264static unsigned long
265rcu_random(struct rcu_random_state *rrsp)
266{
267 if (--rrsp->rrs_count < 0) {
268 rrsp->rrs_state += (unsigned long)local_clock();
269 rrsp->rrs_count = RCU_RANDOM_REFRESH;
270 }
271 rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
272 return swahw32(rrsp->rrs_state);
273}
274
275static void
276rcu_stutter_wait(char *title)
277{
278 while (stutter_pause_test || !rcutorture_runnable) {
279 if (rcutorture_runnable)
280 schedule_timeout_interruptible(1);
281 else
282 schedule_timeout_interruptible(round_jiffies_relative(HZ));
283 rcutorture_shutdown_absorb(title);
284 }
285}
286
287/*
288 * Operations vector for selecting different types of tests.
289 */
290
291struct rcu_torture_ops {
292 void (*init)(void);
293 void (*cleanup)(void);
294 int (*readlock)(void);
295 void (*read_delay)(struct rcu_random_state *rrsp);
296 void (*readunlock)(int idx);
297 int (*completed)(void);
298 void (*deferred_free)(struct rcu_torture *p);
299 void (*sync)(void);
300 void (*cb_barrier)(void);
301 void (*fqs)(void);
302 int (*stats)(char *page);
303 int irq_capable;
304 int can_boost;
305 char *name;
306};
307
308static struct rcu_torture_ops *cur_ops;
309
310/*
311 * Definitions for rcu torture testing.
312 */
313
314static int rcu_torture_read_lock(void) __acquires(RCU)
315{
316 rcu_read_lock();
317 return 0;
318}
319
320static void rcu_read_delay(struct rcu_random_state *rrsp)
321{
322 const unsigned long shortdelay_us = 200;
323 const unsigned long longdelay_ms = 50;
324
325 /* We want a short delay sometimes to make a reader delay the grace
326 * period, and we want a long delay occasionally to trigger
327 * force_quiescent_state. */
328
329 if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
330 mdelay(longdelay_ms);
331 if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
332 udelay(shortdelay_us);
333#ifdef CONFIG_PREEMPT
334 if (!preempt_count() && !(rcu_random(rrsp) % (nrealreaders * 20000)))
335 preempt_schedule(); /* No QS if preempt_disable() in effect */
336#endif
337}
338
339static void rcu_torture_read_unlock(int idx) __releases(RCU)
340{
341 rcu_read_unlock();
342}
343
344static int rcu_torture_completed(void)
345{
346 return rcu_batches_completed();
347}
348
349static void
350rcu_torture_cb(struct rcu_head *p)
351{
352 int i;
353 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
354
355 if (fullstop != FULLSTOP_DONTSTOP) {
356 /* Test is ending, just drop callbacks on the floor. */
357 /* The next initialization will pick up the pieces. */
358 return;
359 }
360 i = rp->rtort_pipe_count;
361 if (i > RCU_TORTURE_PIPE_LEN)
362 i = RCU_TORTURE_PIPE_LEN;
363 atomic_inc(&rcu_torture_wcount[i]);
364 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
365 rp->rtort_mbtest = 0;
366 rcu_torture_free(rp);
367 } else
368 cur_ops->deferred_free(rp);
369}
370
371static int rcu_no_completed(void)
372{
373 return 0;
374}
375
376static void rcu_torture_deferred_free(struct rcu_torture *p)
377{
378 call_rcu(&p->rtort_rcu, rcu_torture_cb);
379}
380
381static struct rcu_torture_ops rcu_ops = {
382 .init = NULL,
383 .cleanup = NULL,
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_torture_deferred_free,
389 .sync = synchronize_rcu,
390 .cb_barrier = rcu_barrier,
391 .fqs = rcu_force_quiescent_state,
392 .stats = NULL,
393 .irq_capable = 1,
394 .can_boost = rcu_can_boost(),
395 .name = "rcu"
396};
397
398static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
399{
400 int i;
401 struct rcu_torture *rp;
402 struct rcu_torture *rp1;
403
404 cur_ops->sync();
405 list_add(&p->rtort_free, &rcu_torture_removed);
406 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
407 i = rp->rtort_pipe_count;
408 if (i > RCU_TORTURE_PIPE_LEN)
409 i = RCU_TORTURE_PIPE_LEN;
410 atomic_inc(&rcu_torture_wcount[i]);
411 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
412 rp->rtort_mbtest = 0;
413 list_del(&rp->rtort_free);
414 rcu_torture_free(rp);
415 }
416 }
417}
418
419static void rcu_sync_torture_init(void)
420{
421 INIT_LIST_HEAD(&rcu_torture_removed);
422}
423
424static struct rcu_torture_ops rcu_sync_ops = {
425 .init = rcu_sync_torture_init,
426 .cleanup = NULL,
427 .readlock = rcu_torture_read_lock,
428 .read_delay = rcu_read_delay,
429 .readunlock = rcu_torture_read_unlock,
430 .completed = rcu_torture_completed,
431 .deferred_free = rcu_sync_torture_deferred_free,
432 .sync = synchronize_rcu,
433 .cb_barrier = NULL,
434 .fqs = rcu_force_quiescent_state,
435 .stats = NULL,
436 .irq_capable = 1,
437 .can_boost = rcu_can_boost(),
438 .name = "rcu_sync"
439};
440
441static struct rcu_torture_ops rcu_expedited_ops = {
442 .init = rcu_sync_torture_init,
443 .cleanup = NULL,
444 .readlock = rcu_torture_read_lock,
445 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
446 .readunlock = rcu_torture_read_unlock,
447 .completed = rcu_no_completed,
448 .deferred_free = rcu_sync_torture_deferred_free,
449 .sync = synchronize_rcu_expedited,
450 .cb_barrier = NULL,
451 .fqs = rcu_force_quiescent_state,
452 .stats = NULL,
453 .irq_capable = 1,
454 .can_boost = rcu_can_boost(),
455 .name = "rcu_expedited"
456};
457
458/*
459 * Definitions for rcu_bh torture testing.
460 */
461
462static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
463{
464 rcu_read_lock_bh();
465 return 0;
466}
467
468static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
469{
470 rcu_read_unlock_bh();
471}
472
473static int rcu_bh_torture_completed(void)
474{
475 return rcu_batches_completed_bh();
476}
477
478static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
479{
480 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
481}
482
483struct rcu_bh_torture_synchronize {
484 struct rcu_head head;
485 struct completion completion;
486};
487
488static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head)
489{
490 struct rcu_bh_torture_synchronize *rcu;
491
492 rcu = container_of(head, struct rcu_bh_torture_synchronize, head);
493 complete(&rcu->completion);
494}
495
496static void rcu_bh_torture_synchronize(void)
497{
498 struct rcu_bh_torture_synchronize rcu;
499
500 init_rcu_head_on_stack(&rcu.head);
501 init_completion(&rcu.completion);
502 call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
503 wait_for_completion(&rcu.completion);
504 destroy_rcu_head_on_stack(&rcu.head);
505}
506
507static struct rcu_torture_ops rcu_bh_ops = {
508 .init = NULL,
509 .cleanup = NULL,
510 .readlock = rcu_bh_torture_read_lock,
511 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
512 .readunlock = rcu_bh_torture_read_unlock,
513 .completed = rcu_bh_torture_completed,
514 .deferred_free = rcu_bh_torture_deferred_free,
515 .sync = rcu_bh_torture_synchronize,
516 .cb_barrier = rcu_barrier_bh,
517 .fqs = rcu_bh_force_quiescent_state,
518 .stats = NULL,
519 .irq_capable = 1,
520 .name = "rcu_bh"
521};
522
523static struct rcu_torture_ops rcu_bh_sync_ops = {
524 .init = rcu_sync_torture_init,
525 .cleanup = NULL,
526 .readlock = rcu_bh_torture_read_lock,
527 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
528 .readunlock = rcu_bh_torture_read_unlock,
529 .completed = rcu_bh_torture_completed,
530 .deferred_free = rcu_sync_torture_deferred_free,
531 .sync = rcu_bh_torture_synchronize,
532 .cb_barrier = NULL,
533 .fqs = rcu_bh_force_quiescent_state,
534 .stats = NULL,
535 .irq_capable = 1,
536 .name = "rcu_bh_sync"
537};
538
539/*
540 * Definitions for srcu torture testing.
541 */
542
543static struct srcu_struct srcu_ctl;
544
545static void srcu_torture_init(void)
546{
547 init_srcu_struct(&srcu_ctl);
548 rcu_sync_torture_init();
549}
550
551static void srcu_torture_cleanup(void)
552{
553 synchronize_srcu(&srcu_ctl);
554 cleanup_srcu_struct(&srcu_ctl);
555}
556
557static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
558{
559 return srcu_read_lock(&srcu_ctl);
560}
561
562static void srcu_read_delay(struct rcu_random_state *rrsp)
563{
564 long delay;
565 const long uspertick = 1000000 / HZ;
566 const long longdelay = 10;
567
568 /* We want there to be long-running readers, but not all the time. */
569
570 delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
571 if (!delay)
572 schedule_timeout_interruptible(longdelay);
573 else
574 rcu_read_delay(rrsp);
575}
576
577static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
578{
579 srcu_read_unlock(&srcu_ctl, idx);
580}
581
582static int srcu_torture_completed(void)
583{
584 return srcu_batches_completed(&srcu_ctl);
585}
586
587static void srcu_torture_synchronize(void)
588{
589 synchronize_srcu(&srcu_ctl);
590}
591
592static int srcu_torture_stats(char *page)
593{
594 int cnt = 0;
595 int cpu;
596 int idx = srcu_ctl.completed & 0x1;
597
598 cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
599 torture_type, TORTURE_FLAG, idx);
600 for_each_possible_cpu(cpu) {
601 cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu,
602 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
603 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
604 }
605 cnt += sprintf(&page[cnt], "\n");
606 return cnt;
607}
608
609static struct rcu_torture_ops srcu_ops = {
610 .init = srcu_torture_init,
611 .cleanup = srcu_torture_cleanup,
612 .readlock = srcu_torture_read_lock,
613 .read_delay = srcu_read_delay,
614 .readunlock = srcu_torture_read_unlock,
615 .completed = srcu_torture_completed,
616 .deferred_free = rcu_sync_torture_deferred_free,
617 .sync = srcu_torture_synchronize,
618 .cb_barrier = NULL,
619 .stats = srcu_torture_stats,
620 .name = "srcu"
621};
622
623static void srcu_torture_synchronize_expedited(void)
624{
625 synchronize_srcu_expedited(&srcu_ctl);
626}
627
628static struct rcu_torture_ops srcu_expedited_ops = {
629 .init = srcu_torture_init,
630 .cleanup = srcu_torture_cleanup,
631 .readlock = srcu_torture_read_lock,
632 .read_delay = srcu_read_delay,
633 .readunlock = srcu_torture_read_unlock,
634 .completed = srcu_torture_completed,
635 .deferred_free = rcu_sync_torture_deferred_free,
636 .sync = srcu_torture_synchronize_expedited,
637 .cb_barrier = NULL,
638 .stats = srcu_torture_stats,
639 .name = "srcu_expedited"
640};
641
642/*
643 * Definitions for sched torture testing.
644 */
645
646static int sched_torture_read_lock(void)
647{
648 preempt_disable();
649 return 0;
650}
651
652static void sched_torture_read_unlock(int idx)
653{
654 preempt_enable();
655}
656
657static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
658{
659 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
660}
661
662static void sched_torture_synchronize(void)
663{
664 synchronize_sched();
665}
666
667static struct rcu_torture_ops sched_ops = {
668 .init = rcu_sync_torture_init,
669 .cleanup = NULL,
670 .readlock = sched_torture_read_lock,
671 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
672 .readunlock = sched_torture_read_unlock,
673 .completed = rcu_no_completed,
674 .deferred_free = rcu_sched_torture_deferred_free,
675 .sync = sched_torture_synchronize,
676 .cb_barrier = rcu_barrier_sched,
677 .fqs = rcu_sched_force_quiescent_state,
678 .stats = NULL,
679 .irq_capable = 1,
680 .name = "sched"
681};
682
683static struct rcu_torture_ops sched_sync_ops = {
684 .init = rcu_sync_torture_init,
685 .cleanup = NULL,
686 .readlock = sched_torture_read_lock,
687 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
688 .readunlock = sched_torture_read_unlock,
689 .completed = rcu_no_completed,
690 .deferred_free = rcu_sync_torture_deferred_free,
691 .sync = sched_torture_synchronize,
692 .cb_barrier = NULL,
693 .fqs = rcu_sched_force_quiescent_state,
694 .stats = NULL,
695 .name = "sched_sync"
696};
697
698static struct rcu_torture_ops sched_expedited_ops = {
699 .init = rcu_sync_torture_init,
700 .cleanup = NULL,
701 .readlock = sched_torture_read_lock,
702 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
703 .readunlock = sched_torture_read_unlock,
704 .completed = rcu_no_completed,
705 .deferred_free = rcu_sync_torture_deferred_free,
706 .sync = synchronize_sched_expedited,
707 .cb_barrier = NULL,
708 .fqs = rcu_sched_force_quiescent_state,
709 .stats = NULL,
710 .irq_capable = 1,
711 .name = "sched_expedited"
712};
713
714/*
715 * RCU torture priority-boost testing. Runs one real-time thread per
716 * CPU for moderate bursts, repeatedly registering RCU callbacks and
717 * spinning waiting for them to be invoked. If a given callback takes
718 * too long to be invoked, we assume that priority inversion has occurred.
719 */
720
721struct rcu_boost_inflight {
722 struct rcu_head rcu;
723 int inflight;
724};
725
726static void rcu_torture_boost_cb(struct rcu_head *head)
727{
728 struct rcu_boost_inflight *rbip =
729 container_of(head, struct rcu_boost_inflight, rcu);
730
731 smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
732 rbip->inflight = 0;
733}
734
735static int rcu_torture_boost(void *arg)
736{
737 unsigned long call_rcu_time;
738 unsigned long endtime;
739 unsigned long oldstarttime;
740 struct rcu_boost_inflight rbi = { .inflight = 0 };
741 struct sched_param sp;
742
743 VERBOSE_PRINTK_STRING("rcu_torture_boost started");
744
745 /* Set real-time priority. */
746 sp.sched_priority = 1;
747 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
748 VERBOSE_PRINTK_STRING("rcu_torture_boost RT prio failed!");
749 n_rcu_torture_boost_rterror++;
750 }
751
752 init_rcu_head_on_stack(&rbi.rcu);
753 /* Each pass through the following loop does one boost-test cycle. */
754 do {
755 /* Wait for the next test interval. */
756 oldstarttime = boost_starttime;
757 while (jiffies - oldstarttime > ULONG_MAX / 2) {
758 schedule_timeout_uninterruptible(1);
759 rcu_stutter_wait("rcu_torture_boost");
760 if (kthread_should_stop() ||
761 fullstop != FULLSTOP_DONTSTOP)
762 goto checkwait;
763 }
764
765 /* Do one boost-test interval. */
766 endtime = oldstarttime + test_boost_duration * HZ;
767 call_rcu_time = jiffies;
768 while (jiffies - endtime > ULONG_MAX / 2) {
769 /* If we don't have a callback in flight, post one. */
770 if (!rbi.inflight) {
771 smp_mb(); /* RCU core before ->inflight = 1. */
772 rbi.inflight = 1;
773 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
774 if (jiffies - call_rcu_time >
775 test_boost_duration * HZ - HZ / 2) {
776 VERBOSE_PRINTK_STRING("rcu_torture_boost boosting failed");
777 n_rcu_torture_boost_failure++;
778 }
779 call_rcu_time = jiffies;
780 }
781 cond_resched();
782 rcu_stutter_wait("rcu_torture_boost");
783 if (kthread_should_stop() ||
784 fullstop != FULLSTOP_DONTSTOP)
785 goto checkwait;
786 }
787
788 /*
789 * Set the start time of the next test interval.
790 * Yes, this is vulnerable to long delays, but such
791 * delays simply cause a false negative for the next
792 * interval. Besides, we are running at RT priority,
793 * so delays should be relatively rare.
794 */
795 while (oldstarttime == boost_starttime) {
796 if (mutex_trylock(&boost_mutex)) {
797 boost_starttime = jiffies +
798 test_boost_interval * HZ;
799 n_rcu_torture_boosts++;
800 mutex_unlock(&boost_mutex);
801 break;
802 }
803 schedule_timeout_uninterruptible(1);
804 }
805
806 /* Go do the stutter. */
807checkwait: rcu_stutter_wait("rcu_torture_boost");
808 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
809
810 /* Clean up and exit. */
811 VERBOSE_PRINTK_STRING("rcu_torture_boost task stopping");
812 destroy_rcu_head_on_stack(&rbi.rcu);
813 rcutorture_shutdown_absorb("rcu_torture_boost");
814 while (!kthread_should_stop() || rbi.inflight)
815 schedule_timeout_uninterruptible(1);
816 smp_mb(); /* order accesses to ->inflight before stack-frame death. */
817 return 0;
818}
819
820/*
821 * RCU torture force-quiescent-state kthread. Repeatedly induces
822 * bursts of calls to force_quiescent_state(), increasing the probability
823 * of occurrence of some important types of race conditions.
824 */
825static int
826rcu_torture_fqs(void *arg)
827{
828 unsigned long fqs_resume_time;
829 int fqs_burst_remaining;
830
831 VERBOSE_PRINTK_STRING("rcu_torture_fqs task started");
832 do {
833 fqs_resume_time = jiffies + fqs_stutter * HZ;
834 while (jiffies - fqs_resume_time > LONG_MAX) {
835 schedule_timeout_interruptible(1);
836 }
837 fqs_burst_remaining = fqs_duration;
838 while (fqs_burst_remaining > 0) {
839 cur_ops->fqs();
840 udelay(fqs_holdoff);
841 fqs_burst_remaining -= fqs_holdoff;
842 }
843 rcu_stutter_wait("rcu_torture_fqs");
844 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
845 VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping");
846 rcutorture_shutdown_absorb("rcu_torture_fqs");
847 while (!kthread_should_stop())
848 schedule_timeout_uninterruptible(1);
849 return 0;
850}
851
852/*
853 * RCU torture writer kthread. Repeatedly substitutes a new structure
854 * for that pointed to by rcu_torture_current, freeing the old structure
855 * after a series of grace periods (the "pipeline").
856 */
857static int
858rcu_torture_writer(void *arg)
859{
860 int i;
861 long oldbatch = rcu_batches_completed();
862 struct rcu_torture *rp;
863 struct rcu_torture *old_rp;
864 static DEFINE_RCU_RANDOM(rand);
865
866 VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
867 set_user_nice(current, 19);
868
869 do {
870 schedule_timeout_uninterruptible(1);
871 rp = rcu_torture_alloc();
872 if (rp == NULL)
873 continue;
874 rp->rtort_pipe_count = 0;
875 udelay(rcu_random(&rand) & 0x3ff);
876 old_rp = rcu_dereference_check(rcu_torture_current,
877 current == writer_task);
878 rp->rtort_mbtest = 1;
879 rcu_assign_pointer(rcu_torture_current, rp);
880 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
881 if (old_rp) {
882 i = old_rp->rtort_pipe_count;
883 if (i > RCU_TORTURE_PIPE_LEN)
884 i = RCU_TORTURE_PIPE_LEN;
885 atomic_inc(&rcu_torture_wcount[i]);
886 old_rp->rtort_pipe_count++;
887 cur_ops->deferred_free(old_rp);
888 }
889 rcutorture_record_progress(++rcu_torture_current_version);
890 oldbatch = cur_ops->completed();
891 rcu_stutter_wait("rcu_torture_writer");
892 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
893 VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
894 rcutorture_shutdown_absorb("rcu_torture_writer");
895 while (!kthread_should_stop())
896 schedule_timeout_uninterruptible(1);
897 return 0;
898}
899
900/*
901 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
902 * delay between calls.
903 */
904static int
905rcu_torture_fakewriter(void *arg)
906{
907 DEFINE_RCU_RANDOM(rand);
908
909 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
910 set_user_nice(current, 19);
911
912 do {
913 schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
914 udelay(rcu_random(&rand) & 0x3ff);
915 cur_ops->sync();
916 rcu_stutter_wait("rcu_torture_fakewriter");
917 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
918
919 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
920 rcutorture_shutdown_absorb("rcu_torture_fakewriter");
921 while (!kthread_should_stop())
922 schedule_timeout_uninterruptible(1);
923 return 0;
924}
925
926/*
927 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
928 * incrementing the corresponding element of the pipeline array. The
929 * counter in the element should never be greater than 1, otherwise, the
930 * RCU implementation is broken.
931 */
932static void rcu_torture_timer(unsigned long unused)
933{
934 int idx;
935 int completed;
936 static DEFINE_RCU_RANDOM(rand);
937 static DEFINE_SPINLOCK(rand_lock);
938 struct rcu_torture *p;
939 int pipe_count;
940
941 idx = cur_ops->readlock();
942 completed = cur_ops->completed();
943 p = rcu_dereference_check(rcu_torture_current,
944 rcu_read_lock_bh_held() ||
945 rcu_read_lock_sched_held() ||
946 srcu_read_lock_held(&srcu_ctl));
947 if (p == NULL) {
948 /* Leave because rcu_torture_writer is not yet underway */
949 cur_ops->readunlock(idx);
950 return;
951 }
952 if (p->rtort_mbtest == 0)
953 atomic_inc(&n_rcu_torture_mberror);
954 spin_lock(&rand_lock);
955 cur_ops->read_delay(&rand);
956 n_rcu_torture_timers++;
957 spin_unlock(&rand_lock);
958 preempt_disable();
959 pipe_count = p->rtort_pipe_count;
960 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
961 /* Should not happen, but... */
962 pipe_count = RCU_TORTURE_PIPE_LEN;
963 }
964 __this_cpu_inc(rcu_torture_count[pipe_count]);
965 completed = cur_ops->completed() - completed;
966 if (completed > RCU_TORTURE_PIPE_LEN) {
967 /* Should not happen, but... */
968 completed = RCU_TORTURE_PIPE_LEN;
969 }
970 __this_cpu_inc(rcu_torture_batch[completed]);
971 preempt_enable();
972 cur_ops->readunlock(idx);
973}
974
975/*
976 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
977 * incrementing the corresponding element of the pipeline array. The
978 * counter in the element should never be greater than 1, otherwise, the
979 * RCU implementation is broken.
980 */
981static int
982rcu_torture_reader(void *arg)
983{
984 int completed;
985 int idx;
986 DEFINE_RCU_RANDOM(rand);
987 struct rcu_torture *p;
988 int pipe_count;
989 struct timer_list t;
990
991 VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
992 set_user_nice(current, 19);
993 if (irqreader && cur_ops->irq_capable)
994 setup_timer_on_stack(&t, rcu_torture_timer, 0);
995
996 do {
997 if (irqreader && cur_ops->irq_capable) {
998 if (!timer_pending(&t))
999 mod_timer(&t, jiffies + 1);
1000 }
1001 idx = cur_ops->readlock();
1002 completed = cur_ops->completed();
1003 p = rcu_dereference_check(rcu_torture_current,
1004 rcu_read_lock_bh_held() ||
1005 rcu_read_lock_sched_held() ||
1006 srcu_read_lock_held(&srcu_ctl));
1007 if (p == NULL) {
1008 /* Wait for rcu_torture_writer to get underway */
1009 cur_ops->readunlock(idx);
1010 schedule_timeout_interruptible(HZ);
1011 continue;
1012 }
1013 if (p->rtort_mbtest == 0)
1014 atomic_inc(&n_rcu_torture_mberror);
1015 cur_ops->read_delay(&rand);
1016 preempt_disable();
1017 pipe_count = p->rtort_pipe_count;
1018 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1019 /* Should not happen, but... */
1020 pipe_count = RCU_TORTURE_PIPE_LEN;
1021 }
1022 __this_cpu_inc(rcu_torture_count[pipe_count]);
1023 completed = cur_ops->completed() - completed;
1024 if (completed > RCU_TORTURE_PIPE_LEN) {
1025 /* Should not happen, but... */
1026 completed = RCU_TORTURE_PIPE_LEN;
1027 }
1028 __this_cpu_inc(rcu_torture_batch[completed]);
1029 preempt_enable();
1030 cur_ops->readunlock(idx);
1031 schedule();
1032 rcu_stutter_wait("rcu_torture_reader");
1033 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1034 VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
1035 rcutorture_shutdown_absorb("rcu_torture_reader");
1036 if (irqreader && cur_ops->irq_capable)
1037 del_timer_sync(&t);
1038 while (!kthread_should_stop())
1039 schedule_timeout_uninterruptible(1);
1040 return 0;
1041}
1042
1043/*
1044 * Create an RCU-torture statistics message in the specified buffer.
1045 */
1046static int
1047rcu_torture_printk(char *page)
1048{
1049 int cnt = 0;
1050 int cpu;
1051 int i;
1052 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1053 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1054
1055 for_each_possible_cpu(cpu) {
1056 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1057 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1058 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1059 }
1060 }
1061 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1062 if (pipesummary[i] != 0)
1063 break;
1064 }
1065 cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
1066 cnt += sprintf(&page[cnt],
1067 "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d "
1068 "rtmbe: %d rtbke: %ld rtbre: %ld "
1069 "rtbf: %ld rtb: %ld nt: %ld",
1070 rcu_torture_current,
1071 rcu_torture_current_version,
1072 list_empty(&rcu_torture_freelist),
1073 atomic_read(&n_rcu_torture_alloc),
1074 atomic_read(&n_rcu_torture_alloc_fail),
1075 atomic_read(&n_rcu_torture_free),
1076 atomic_read(&n_rcu_torture_mberror),
1077 n_rcu_torture_boost_ktrerror,
1078 n_rcu_torture_boost_rterror,
1079 n_rcu_torture_boost_failure,
1080 n_rcu_torture_boosts,
1081 n_rcu_torture_timers);
1082 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1083 n_rcu_torture_boost_ktrerror != 0 ||
1084 n_rcu_torture_boost_rterror != 0 ||
1085 n_rcu_torture_boost_failure != 0)
1086 cnt += sprintf(&page[cnt], " !!!");
1087 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1088 if (i > 1) {
1089 cnt += sprintf(&page[cnt], "!!! ");
1090 atomic_inc(&n_rcu_torture_error);
1091 WARN_ON_ONCE(1);
1092 }
1093 cnt += sprintf(&page[cnt], "Reader Pipe: ");
1094 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1095 cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
1096 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1097 cnt += sprintf(&page[cnt], "Reader Batch: ");
1098 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1099 cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
1100 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1101 cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
1102 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1103 cnt += sprintf(&page[cnt], " %d",
1104 atomic_read(&rcu_torture_wcount[i]));
1105 }
1106 cnt += sprintf(&page[cnt], "\n");
1107 if (cur_ops->stats)
1108 cnt += cur_ops->stats(&page[cnt]);
1109 return cnt;
1110}
1111
1112/*
1113 * Print torture statistics. Caller must ensure that there is only
1114 * one call to this function at a given time!!! This is normally
1115 * accomplished by relying on the module system to only have one copy
1116 * of the module loaded, and then by giving the rcu_torture_stats
1117 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1118 * thread is not running).
1119 */
1120static void
1121rcu_torture_stats_print(void)
1122{
1123 int cnt;
1124
1125 cnt = rcu_torture_printk(printk_buf);
1126 printk(KERN_ALERT "%s", printk_buf);
1127}
1128
1129/*
1130 * Periodically prints torture statistics, if periodic statistics printing
1131 * was specified via the stat_interval module parameter.
1132 *
1133 * No need to worry about fullstop here, since this one doesn't reference
1134 * volatile state or register callbacks.
1135 */
1136static int
1137rcu_torture_stats(void *arg)
1138{
1139 VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
1140 do {
1141 schedule_timeout_interruptible(stat_interval * HZ);
1142 rcu_torture_stats_print();
1143 rcutorture_shutdown_absorb("rcu_torture_stats");
1144 } while (!kthread_should_stop());
1145 VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
1146 return 0;
1147}
1148
1149static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
1150
1151/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
1152 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
1153 */
1154static void rcu_torture_shuffle_tasks(void)
1155{
1156 int i;
1157
1158 cpumask_setall(shuffle_tmp_mask);
1159 get_online_cpus();
1160
1161 /* No point in shuffling if there is only one online CPU (ex: UP) */
1162 if (num_online_cpus() == 1) {
1163 put_online_cpus();
1164 return;
1165 }
1166
1167 if (rcu_idle_cpu != -1)
1168 cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
1169
1170 set_cpus_allowed_ptr(current, shuffle_tmp_mask);
1171
1172 if (reader_tasks) {
1173 for (i = 0; i < nrealreaders; i++)
1174 if (reader_tasks[i])
1175 set_cpus_allowed_ptr(reader_tasks[i],
1176 shuffle_tmp_mask);
1177 }
1178
1179 if (fakewriter_tasks) {
1180 for (i = 0; i < nfakewriters; i++)
1181 if (fakewriter_tasks[i])
1182 set_cpus_allowed_ptr(fakewriter_tasks[i],
1183 shuffle_tmp_mask);
1184 }
1185
1186 if (writer_task)
1187 set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
1188
1189 if (stats_task)
1190 set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
1191
1192 if (rcu_idle_cpu == -1)
1193 rcu_idle_cpu = num_online_cpus() - 1;
1194 else
1195 rcu_idle_cpu--;
1196
1197 put_online_cpus();
1198}
1199
1200/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
1201 * system to become idle at a time and cut off its timer ticks. This is meant
1202 * to test the support for such tickless idle CPU in RCU.
1203 */
1204static int
1205rcu_torture_shuffle(void *arg)
1206{
1207 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
1208 do {
1209 schedule_timeout_interruptible(shuffle_interval * HZ);
1210 rcu_torture_shuffle_tasks();
1211 rcutorture_shutdown_absorb("rcu_torture_shuffle");
1212 } while (!kthread_should_stop());
1213 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
1214 return 0;
1215}
1216
1217/* Cause the rcutorture test to "stutter", starting and stopping all
1218 * threads periodically.
1219 */
1220static int
1221rcu_torture_stutter(void *arg)
1222{
1223 VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
1224 do {
1225 schedule_timeout_interruptible(stutter * HZ);
1226 stutter_pause_test = 1;
1227 if (!kthread_should_stop())
1228 schedule_timeout_interruptible(stutter * HZ);
1229 stutter_pause_test = 0;
1230 rcutorture_shutdown_absorb("rcu_torture_stutter");
1231 } while (!kthread_should_stop());
1232 VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
1233 return 0;
1234}
1235
1236static inline void
1237rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, char *tag)
1238{
1239 printk(KERN_ALERT "%s" TORTURE_FLAG
1240 "--- %s: nreaders=%d nfakewriters=%d "
1241 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1242 "shuffle_interval=%d stutter=%d irqreader=%d "
1243 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1244 "test_boost=%d/%d test_boost_interval=%d "
1245 "test_boost_duration=%d\n",
1246 torture_type, tag, nrealreaders, nfakewriters,
1247 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1248 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1249 test_boost, cur_ops->can_boost,
1250 test_boost_interval, test_boost_duration);
1251}
1252
1253static struct notifier_block rcutorture_shutdown_nb = {
1254 .notifier_call = rcutorture_shutdown_notify,
1255};
1256
1257static void rcutorture_booster_cleanup(int cpu)
1258{
1259 struct task_struct *t;
1260
1261 if (boost_tasks[cpu] == NULL)
1262 return;
1263 mutex_lock(&boost_mutex);
1264 VERBOSE_PRINTK_STRING("Stopping rcu_torture_boost task");
1265 t = boost_tasks[cpu];
1266 boost_tasks[cpu] = NULL;
1267 mutex_unlock(&boost_mutex);
1268
1269 /* This must be outside of the mutex, otherwise deadlock! */
1270 kthread_stop(t);
1271}
1272
1273static int rcutorture_booster_init(int cpu)
1274{
1275 int retval;
1276
1277 if (boost_tasks[cpu] != NULL)
1278 return 0; /* Already created, nothing more to do. */
1279
1280 /* Don't allow time recalculation while creating a new task. */
1281 mutex_lock(&boost_mutex);
1282 VERBOSE_PRINTK_STRING("Creating rcu_torture_boost task");
1283 boost_tasks[cpu] = kthread_create(rcu_torture_boost, NULL,
1284 "rcu_torture_boost");
1285 if (IS_ERR(boost_tasks[cpu])) {
1286 retval = PTR_ERR(boost_tasks[cpu]);
1287 VERBOSE_PRINTK_STRING("rcu_torture_boost task create failed");
1288 n_rcu_torture_boost_ktrerror++;
1289 boost_tasks[cpu] = NULL;
1290 mutex_unlock(&boost_mutex);
1291 return retval;
1292 }
1293 kthread_bind(boost_tasks[cpu], cpu);
1294 wake_up_process(boost_tasks[cpu]);
1295 mutex_unlock(&boost_mutex);
1296 return 0;
1297}
1298
1299static int rcutorture_cpu_notify(struct notifier_block *self,
1300 unsigned long action, void *hcpu)
1301{
1302 long cpu = (long)hcpu;
1303
1304 switch (action) {
1305 case CPU_ONLINE:
1306 case CPU_DOWN_FAILED:
1307 (void)rcutorture_booster_init(cpu);
1308 break;
1309 case CPU_DOWN_PREPARE:
1310 rcutorture_booster_cleanup(cpu);
1311 break;
1312 default:
1313 break;
1314 }
1315 return NOTIFY_OK;
1316}
1317
1318static struct notifier_block rcutorture_cpu_nb = {
1319 .notifier_call = rcutorture_cpu_notify,
1320};
1321
1322static void
1323rcu_torture_cleanup(void)
1324{
1325 int i;
1326
1327 mutex_lock(&fullstop_mutex);
1328 rcutorture_record_test_transition();
1329 if (fullstop == FULLSTOP_SHUTDOWN) {
1330 printk(KERN_WARNING /* but going down anyway, so... */
1331 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
1332 mutex_unlock(&fullstop_mutex);
1333 schedule_timeout_uninterruptible(10);
1334 if (cur_ops->cb_barrier != NULL)
1335 cur_ops->cb_barrier();
1336 return;
1337 }
1338 fullstop = FULLSTOP_RMMOD;
1339 mutex_unlock(&fullstop_mutex);
1340 unregister_reboot_notifier(&rcutorture_shutdown_nb);
1341 if (stutter_task) {
1342 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1343 kthread_stop(stutter_task);
1344 }
1345 stutter_task = NULL;
1346 if (shuffler_task) {
1347 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1348 kthread_stop(shuffler_task);
1349 free_cpumask_var(shuffle_tmp_mask);
1350 }
1351 shuffler_task = NULL;
1352
1353 if (writer_task) {
1354 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1355 kthread_stop(writer_task);
1356 }
1357 writer_task = NULL;
1358
1359 if (reader_tasks) {
1360 for (i = 0; i < nrealreaders; i++) {
1361 if (reader_tasks[i]) {
1362 VERBOSE_PRINTK_STRING(
1363 "Stopping rcu_torture_reader task");
1364 kthread_stop(reader_tasks[i]);
1365 }
1366 reader_tasks[i] = NULL;
1367 }
1368 kfree(reader_tasks);
1369 reader_tasks = NULL;
1370 }
1371 rcu_torture_current = NULL;
1372
1373 if (fakewriter_tasks) {
1374 for (i = 0; i < nfakewriters; i++) {
1375 if (fakewriter_tasks[i]) {
1376 VERBOSE_PRINTK_STRING(
1377 "Stopping rcu_torture_fakewriter task");
1378 kthread_stop(fakewriter_tasks[i]);
1379 }
1380 fakewriter_tasks[i] = NULL;
1381 }
1382 kfree(fakewriter_tasks);
1383 fakewriter_tasks = NULL;
1384 }
1385
1386 if (stats_task) {
1387 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1388 kthread_stop(stats_task);
1389 }
1390 stats_task = NULL;
1391
1392 if (fqs_task) {
1393 VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task");
1394 kthread_stop(fqs_task);
1395 }
1396 fqs_task = NULL;
1397 if ((test_boost == 1 && cur_ops->can_boost) ||
1398 test_boost == 2) {
1399 unregister_cpu_notifier(&rcutorture_cpu_nb);
1400 for_each_possible_cpu(i)
1401 rcutorture_booster_cleanup(i);
1402 }
1403
1404 /* Wait for all RCU callbacks to fire. */
1405
1406 if (cur_ops->cb_barrier != NULL)
1407 cur_ops->cb_barrier();
1408
1409 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1410
1411 if (cur_ops->cleanup)
1412 cur_ops->cleanup();
1413 if (atomic_read(&n_rcu_torture_error))
1414 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1415 else
1416 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1417}
1418
1419static int __init
1420rcu_torture_init(void)
1421{
1422 int i;
1423 int cpu;
1424 int firsterr = 0;
1425 static struct rcu_torture_ops *torture_ops[] =
1426 { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops,
1427 &rcu_bh_ops, &rcu_bh_sync_ops,
1428 &srcu_ops, &srcu_expedited_ops,
1429 &sched_ops, &sched_sync_ops, &sched_expedited_ops, };
1430
1431 mutex_lock(&fullstop_mutex);
1432
1433 /* Process args and tell the world that the torturer is on the job. */
1434 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1435 cur_ops = torture_ops[i];
1436 if (strcmp(torture_type, cur_ops->name) == 0)
1437 break;
1438 }
1439 if (i == ARRAY_SIZE(torture_ops)) {
1440 printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n",
1441 torture_type);
1442 printk(KERN_ALERT "rcu-torture types:");
1443 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1444 printk(KERN_ALERT " %s", torture_ops[i]->name);
1445 printk(KERN_ALERT "\n");
1446 mutex_unlock(&fullstop_mutex);
1447 return -EINVAL;
1448 }
1449 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1450 printk(KERN_ALERT "rcu-torture: ->fqs NULL and non-zero "
1451 "fqs_duration, fqs disabled.\n");
1452 fqs_duration = 0;
1453 }
1454 if (cur_ops->init)
1455 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1456
1457 if (nreaders >= 0)
1458 nrealreaders = nreaders;
1459 else
1460 nrealreaders = 2 * num_online_cpus();
1461 rcu_torture_print_module_parms(cur_ops, "Start of test");
1462 fullstop = FULLSTOP_DONTSTOP;
1463
1464 /* Set up the freelist. */
1465
1466 INIT_LIST_HEAD(&rcu_torture_freelist);
1467 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1468 rcu_tortures[i].rtort_mbtest = 0;
1469 list_add_tail(&rcu_tortures[i].rtort_free,
1470 &rcu_torture_freelist);
1471 }
1472
1473 /* Initialize the statistics so that each run gets its own numbers. */
1474
1475 rcu_torture_current = NULL;
1476 rcu_torture_current_version = 0;
1477 atomic_set(&n_rcu_torture_alloc, 0);
1478 atomic_set(&n_rcu_torture_alloc_fail, 0);
1479 atomic_set(&n_rcu_torture_free, 0);
1480 atomic_set(&n_rcu_torture_mberror, 0);
1481 atomic_set(&n_rcu_torture_error, 0);
1482 n_rcu_torture_boost_ktrerror = 0;
1483 n_rcu_torture_boost_rterror = 0;
1484 n_rcu_torture_boost_failure = 0;
1485 n_rcu_torture_boosts = 0;
1486 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1487 atomic_set(&rcu_torture_wcount[i], 0);
1488 for_each_possible_cpu(cpu) {
1489 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1490 per_cpu(rcu_torture_count, cpu)[i] = 0;
1491 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1492 }
1493 }
1494
1495 /* Start up the kthreads. */
1496
1497 VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
1498 writer_task = kthread_run(rcu_torture_writer, NULL,
1499 "rcu_torture_writer");
1500 if (IS_ERR(writer_task)) {
1501 firsterr = PTR_ERR(writer_task);
1502 VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
1503 writer_task = NULL;
1504 goto unwind;
1505 }
1506 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
1507 GFP_KERNEL);
1508 if (fakewriter_tasks == NULL) {
1509 VERBOSE_PRINTK_ERRSTRING("out of memory");
1510 firsterr = -ENOMEM;
1511 goto unwind;
1512 }
1513 for (i = 0; i < nfakewriters; i++) {
1514 VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
1515 fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
1516 "rcu_torture_fakewriter");
1517 if (IS_ERR(fakewriter_tasks[i])) {
1518 firsterr = PTR_ERR(fakewriter_tasks[i]);
1519 VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
1520 fakewriter_tasks[i] = NULL;
1521 goto unwind;
1522 }
1523 }
1524 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
1525 GFP_KERNEL);
1526 if (reader_tasks == NULL) {
1527 VERBOSE_PRINTK_ERRSTRING("out of memory");
1528 firsterr = -ENOMEM;
1529 goto unwind;
1530 }
1531 for (i = 0; i < nrealreaders; i++) {
1532 VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
1533 reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
1534 "rcu_torture_reader");
1535 if (IS_ERR(reader_tasks[i])) {
1536 firsterr = PTR_ERR(reader_tasks[i]);
1537 VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
1538 reader_tasks[i] = NULL;
1539 goto unwind;
1540 }
1541 }
1542 if (stat_interval > 0) {
1543 VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
1544 stats_task = kthread_run(rcu_torture_stats, NULL,
1545 "rcu_torture_stats");
1546 if (IS_ERR(stats_task)) {
1547 firsterr = PTR_ERR(stats_task);
1548 VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
1549 stats_task = NULL;
1550 goto unwind;
1551 }
1552 }
1553 if (test_no_idle_hz) {
1554 rcu_idle_cpu = num_online_cpus() - 1;
1555
1556 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
1557 firsterr = -ENOMEM;
1558 VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
1559 goto unwind;
1560 }
1561
1562 /* Create the shuffler thread */
1563 shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
1564 "rcu_torture_shuffle");
1565 if (IS_ERR(shuffler_task)) {
1566 free_cpumask_var(shuffle_tmp_mask);
1567 firsterr = PTR_ERR(shuffler_task);
1568 VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
1569 shuffler_task = NULL;
1570 goto unwind;
1571 }
1572 }
1573 if (stutter < 0)
1574 stutter = 0;
1575 if (stutter) {
1576 /* Create the stutter thread */
1577 stutter_task = kthread_run(rcu_torture_stutter, NULL,
1578 "rcu_torture_stutter");
1579 if (IS_ERR(stutter_task)) {
1580 firsterr = PTR_ERR(stutter_task);
1581 VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
1582 stutter_task = NULL;
1583 goto unwind;
1584 }
1585 }
1586 if (fqs_duration < 0)
1587 fqs_duration = 0;
1588 if (fqs_duration) {
1589 /* Create the stutter thread */
1590 fqs_task = kthread_run(rcu_torture_fqs, NULL,
1591 "rcu_torture_fqs");
1592 if (IS_ERR(fqs_task)) {
1593 firsterr = PTR_ERR(fqs_task);
1594 VERBOSE_PRINTK_ERRSTRING("Failed to create fqs");
1595 fqs_task = NULL;
1596 goto unwind;
1597 }
1598 }
1599 if (test_boost_interval < 1)
1600 test_boost_interval = 1;
1601 if (test_boost_duration < 2)
1602 test_boost_duration = 2;
1603 if ((test_boost == 1 && cur_ops->can_boost) ||
1604 test_boost == 2) {
1605 int retval;
1606
1607 boost_starttime = jiffies + test_boost_interval * HZ;
1608 register_cpu_notifier(&rcutorture_cpu_nb);
1609 for_each_possible_cpu(i) {
1610 if (cpu_is_offline(i))
1611 continue; /* Heuristic: CPU can go offline. */
1612 retval = rcutorture_booster_init(i);
1613 if (retval < 0) {
1614 firsterr = retval;
1615 goto unwind;
1616 }
1617 }
1618 }
1619 register_reboot_notifier(&rcutorture_shutdown_nb);
1620 rcutorture_record_test_transition();
1621 mutex_unlock(&fullstop_mutex);
1622 return 0;
1623
1624unwind:
1625 mutex_unlock(&fullstop_mutex);
1626 rcu_torture_cleanup();
1627 return firsterr;
1628}
1629
1630module_init(rcu_torture_init);
1631module_exit(rcu_torture_cleanup);