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rcu: Fix code-style issues involving "else"
[deliverable/linux.git] / kernel / rcutorture.c
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
51 MODULE_LICENSE("GPL");
52 MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and "
53 "Josh Triplett <josh@freedesktop.org>");
54
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 bool verbose; /* Print more debug info. */
60 static bool 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 int fqs_duration; /* Duration of bursts (us), 0 to disable. */
65 static int fqs_holdoff; /* Hold time within burst (us). */
66 static int fqs_stutter = 3; /* Wait time between bursts (s). */
67 static int n_barrier_cbs; /* Number of callbacks to test RCU barriers. */
68 static int onoff_interval; /* Wait time between CPU hotplugs, 0=disable. */
69 static int onoff_holdoff; /* Seconds after boot before CPU hotplugs. */
70 static int shutdown_secs; /* Shutdown time (s). <=0 for no shutdown. */
71 static int stall_cpu; /* CPU-stall duration (s). 0 for no stall. */
72 static int stall_cpu_holdoff = 10; /* Time to wait until stall (s). */
73 static int test_boost = 1; /* Test RCU prio boost: 0=no, 1=maybe, 2=yes. */
74 static int test_boost_interval = 7; /* Interval between boost tests, seconds. */
75 static int test_boost_duration = 4; /* Duration of each boost test, seconds. */
76 static char *torture_type = "rcu"; /* What RCU implementation to torture. */
77
78 module_param(nreaders, int, 0444);
79 MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
80 module_param(nfakewriters, int, 0444);
81 MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads");
82 module_param(stat_interval, int, 0644);
83 MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
84 module_param(verbose, bool, 0444);
85 MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
86 module_param(test_no_idle_hz, bool, 0444);
87 MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
88 module_param(shuffle_interval, int, 0444);
89 MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
90 module_param(stutter, int, 0444);
91 MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
92 module_param(irqreader, int, 0444);
93 MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
94 module_param(fqs_duration, int, 0444);
95 MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us)");
96 module_param(fqs_holdoff, int, 0444);
97 MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)");
98 module_param(fqs_stutter, int, 0444);
99 MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
100 module_param(n_barrier_cbs, int, 0444);
101 MODULE_PARM_DESC(n_barrier_cbs, "# of callbacks/kthreads for barrier testing");
102 module_param(onoff_interval, int, 0444);
103 MODULE_PARM_DESC(onoff_interval, "Time between CPU hotplugs (s), 0=disable");
104 module_param(onoff_holdoff, int, 0444);
105 MODULE_PARM_DESC(onoff_holdoff, "Time after boot before CPU hotplugs (s)");
106 module_param(shutdown_secs, int, 0444);
107 MODULE_PARM_DESC(shutdown_secs, "Shutdown time (s), zero to disable.");
108 module_param(stall_cpu, int, 0444);
109 MODULE_PARM_DESC(stall_cpu, "Stall duration (s), zero to disable.");
110 module_param(stall_cpu_holdoff, int, 0444);
111 MODULE_PARM_DESC(stall_cpu_holdoff, "Time to wait before starting stall (s).");
112 module_param(test_boost, int, 0444);
113 MODULE_PARM_DESC(test_boost, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
114 module_param(test_boost_interval, int, 0444);
115 MODULE_PARM_DESC(test_boost_interval, "Interval between boost tests, seconds.");
116 module_param(test_boost_duration, int, 0444);
117 MODULE_PARM_DESC(test_boost_duration, "Duration of each boost test, seconds.");
118 module_param(torture_type, charp, 0444);
119 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
120
121 #define TORTURE_FLAG "-torture:"
122 #define PRINTK_STRING(s) \
123 do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
124 #define VERBOSE_PRINTK_STRING(s) \
125 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0)
126 #define VERBOSE_PRINTK_ERRSTRING(s) \
127 do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0)
128
129 static char printk_buf[4096];
130
131 static int nrealreaders;
132 static struct task_struct *writer_task;
133 static struct task_struct **fakewriter_tasks;
134 static struct task_struct **reader_tasks;
135 static struct task_struct *stats_task;
136 static struct task_struct *shuffler_task;
137 static struct task_struct *stutter_task;
138 static struct task_struct *fqs_task;
139 static struct task_struct *boost_tasks[NR_CPUS];
140 static struct task_struct *shutdown_task;
141 #ifdef CONFIG_HOTPLUG_CPU
142 static struct task_struct *onoff_task;
143 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
144 static struct task_struct *stall_task;
145 static struct task_struct **barrier_cbs_tasks;
146 static struct task_struct *barrier_task;
147
148 #define RCU_TORTURE_PIPE_LEN 10
149
150 struct rcu_torture {
151 struct rcu_head rtort_rcu;
152 int rtort_pipe_count;
153 struct list_head rtort_free;
154 int rtort_mbtest;
155 };
156
157 static LIST_HEAD(rcu_torture_freelist);
158 static struct rcu_torture __rcu *rcu_torture_current;
159 static unsigned long rcu_torture_current_version;
160 static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
161 static DEFINE_SPINLOCK(rcu_torture_lock);
162 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
163 { 0 };
164 static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
165 { 0 };
166 static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
167 static atomic_t n_rcu_torture_alloc;
168 static atomic_t n_rcu_torture_alloc_fail;
169 static atomic_t n_rcu_torture_free;
170 static atomic_t n_rcu_torture_mberror;
171 static atomic_t n_rcu_torture_error;
172 static long n_rcu_torture_barrier_error;
173 static long n_rcu_torture_boost_ktrerror;
174 static long n_rcu_torture_boost_rterror;
175 static long n_rcu_torture_boost_failure;
176 static long n_rcu_torture_boosts;
177 static long n_rcu_torture_timers;
178 static long n_offline_attempts;
179 static long n_offline_successes;
180 static long n_online_attempts;
181 static long n_online_successes;
182 static long n_barrier_attempts;
183 static long n_barrier_successes;
184 static struct list_head rcu_torture_removed;
185 static cpumask_var_t shuffle_tmp_mask;
186
187 static int stutter_pause_test;
188
189 #if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
190 #define RCUTORTURE_RUNNABLE_INIT 1
191 #else
192 #define RCUTORTURE_RUNNABLE_INIT 0
193 #endif
194 int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
195 module_param(rcutorture_runnable, int, 0444);
196 MODULE_PARM_DESC(rcutorture_runnable, "Start rcutorture at boot");
197
198 #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU)
199 #define rcu_can_boost() 1
200 #else /* #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
201 #define rcu_can_boost() 0
202 #endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
203
204 static unsigned long shutdown_time; /* jiffies to system shutdown. */
205 static unsigned long boost_starttime; /* jiffies of next boost test start. */
206 DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
207 /* and boost task create/destroy. */
208 static atomic_t barrier_cbs_count; /* Barrier callbacks registered. */
209 static bool barrier_phase; /* Test phase. */
210 static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
211 static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
212 static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
213
214 /* Mediate rmmod and system shutdown. Concurrent rmmod & shutdown illegal! */
215
216 #define FULLSTOP_DONTSTOP 0 /* Normal operation. */
217 #define FULLSTOP_SHUTDOWN 1 /* System shutdown with rcutorture running. */
218 #define FULLSTOP_RMMOD 2 /* Normal rmmod of rcutorture. */
219 static int fullstop = FULLSTOP_RMMOD;
220 /*
221 * Protect fullstop transitions and spawning of kthreads.
222 */
223 static DEFINE_MUTEX(fullstop_mutex);
224
225 /* Forward reference. */
226 static void rcu_torture_cleanup(void);
227
228 /*
229 * Detect and respond to a system shutdown.
230 */
231 static int
232 rcutorture_shutdown_notify(struct notifier_block *unused1,
233 unsigned long unused2, void *unused3)
234 {
235 mutex_lock(&fullstop_mutex);
236 if (fullstop == FULLSTOP_DONTSTOP)
237 fullstop = FULLSTOP_SHUTDOWN;
238 else
239 printk(KERN_WARNING /* but going down anyway, so... */
240 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
241 mutex_unlock(&fullstop_mutex);
242 return NOTIFY_DONE;
243 }
244
245 /*
246 * Absorb kthreads into a kernel function that won't return, so that
247 * they won't ever access module text or data again.
248 */
249 static void rcutorture_shutdown_absorb(char *title)
250 {
251 if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
252 printk(KERN_NOTICE
253 "rcutorture thread %s parking due to system shutdown\n",
254 title);
255 schedule_timeout_uninterruptible(MAX_SCHEDULE_TIMEOUT);
256 }
257 }
258
259 /*
260 * Allocate an element from the rcu_tortures pool.
261 */
262 static struct rcu_torture *
263 rcu_torture_alloc(void)
264 {
265 struct list_head *p;
266
267 spin_lock_bh(&rcu_torture_lock);
268 if (list_empty(&rcu_torture_freelist)) {
269 atomic_inc(&n_rcu_torture_alloc_fail);
270 spin_unlock_bh(&rcu_torture_lock);
271 return NULL;
272 }
273 atomic_inc(&n_rcu_torture_alloc);
274 p = rcu_torture_freelist.next;
275 list_del_init(p);
276 spin_unlock_bh(&rcu_torture_lock);
277 return container_of(p, struct rcu_torture, rtort_free);
278 }
279
280 /*
281 * Free an element to the rcu_tortures pool.
282 */
283 static void
284 rcu_torture_free(struct rcu_torture *p)
285 {
286 atomic_inc(&n_rcu_torture_free);
287 spin_lock_bh(&rcu_torture_lock);
288 list_add_tail(&p->rtort_free, &rcu_torture_freelist);
289 spin_unlock_bh(&rcu_torture_lock);
290 }
291
292 struct rcu_random_state {
293 unsigned long rrs_state;
294 long rrs_count;
295 };
296
297 #define RCU_RANDOM_MULT 39916801 /* prime */
298 #define RCU_RANDOM_ADD 479001701 /* prime */
299 #define RCU_RANDOM_REFRESH 10000
300
301 #define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
302
303 /*
304 * Crude but fast random-number generator. Uses a linear congruential
305 * generator, with occasional help from cpu_clock().
306 */
307 static unsigned long
308 rcu_random(struct rcu_random_state *rrsp)
309 {
310 if (--rrsp->rrs_count < 0) {
311 rrsp->rrs_state += (unsigned long)local_clock();
312 rrsp->rrs_count = RCU_RANDOM_REFRESH;
313 }
314 rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
315 return swahw32(rrsp->rrs_state);
316 }
317
318 static void
319 rcu_stutter_wait(char *title)
320 {
321 while (stutter_pause_test || !rcutorture_runnable) {
322 if (rcutorture_runnable)
323 schedule_timeout_interruptible(1);
324 else
325 schedule_timeout_interruptible(round_jiffies_relative(HZ));
326 rcutorture_shutdown_absorb(title);
327 }
328 }
329
330 /*
331 * Operations vector for selecting different types of tests.
332 */
333
334 struct rcu_torture_ops {
335 void (*init)(void);
336 void (*cleanup)(void);
337 int (*readlock)(void);
338 void (*read_delay)(struct rcu_random_state *rrsp);
339 void (*readunlock)(int idx);
340 int (*completed)(void);
341 void (*deferred_free)(struct rcu_torture *p);
342 void (*sync)(void);
343 void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
344 void (*cb_barrier)(void);
345 void (*fqs)(void);
346 int (*stats)(char *page);
347 int irq_capable;
348 int can_boost;
349 char *name;
350 };
351
352 static struct rcu_torture_ops *cur_ops;
353
354 /*
355 * Definitions for rcu torture testing.
356 */
357
358 static int rcu_torture_read_lock(void) __acquires(RCU)
359 {
360 rcu_read_lock();
361 return 0;
362 }
363
364 static void rcu_read_delay(struct rcu_random_state *rrsp)
365 {
366 const unsigned long shortdelay_us = 200;
367 const unsigned long longdelay_ms = 50;
368
369 /* We want a short delay sometimes to make a reader delay the grace
370 * period, and we want a long delay occasionally to trigger
371 * force_quiescent_state. */
372
373 if (!(rcu_random(rrsp) % (nrealreaders * 2000 * longdelay_ms)))
374 mdelay(longdelay_ms);
375 if (!(rcu_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
376 udelay(shortdelay_us);
377 #ifdef CONFIG_PREEMPT
378 if (!preempt_count() && !(rcu_random(rrsp) % (nrealreaders * 20000)))
379 preempt_schedule(); /* No QS if preempt_disable() in effect */
380 #endif
381 }
382
383 static void rcu_torture_read_unlock(int idx) __releases(RCU)
384 {
385 rcu_read_unlock();
386 }
387
388 static int rcu_torture_completed(void)
389 {
390 return rcu_batches_completed();
391 }
392
393 static void
394 rcu_torture_cb(struct rcu_head *p)
395 {
396 int i;
397 struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
398
399 if (fullstop != FULLSTOP_DONTSTOP) {
400 /* Test is ending, just drop callbacks on the floor. */
401 /* The next initialization will pick up the pieces. */
402 return;
403 }
404 i = rp->rtort_pipe_count;
405 if (i > RCU_TORTURE_PIPE_LEN)
406 i = RCU_TORTURE_PIPE_LEN;
407 atomic_inc(&rcu_torture_wcount[i]);
408 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
409 rp->rtort_mbtest = 0;
410 rcu_torture_free(rp);
411 } else {
412 cur_ops->deferred_free(rp);
413 }
414 }
415
416 static int rcu_no_completed(void)
417 {
418 return 0;
419 }
420
421 static void rcu_torture_deferred_free(struct rcu_torture *p)
422 {
423 call_rcu(&p->rtort_rcu, rcu_torture_cb);
424 }
425
426 static struct rcu_torture_ops rcu_ops = {
427 .init = NULL,
428 .cleanup = NULL,
429 .readlock = rcu_torture_read_lock,
430 .read_delay = rcu_read_delay,
431 .readunlock = rcu_torture_read_unlock,
432 .completed = rcu_torture_completed,
433 .deferred_free = rcu_torture_deferred_free,
434 .sync = synchronize_rcu,
435 .call = call_rcu,
436 .cb_barrier = rcu_barrier,
437 .fqs = rcu_force_quiescent_state,
438 .stats = NULL,
439 .irq_capable = 1,
440 .can_boost = rcu_can_boost(),
441 .name = "rcu"
442 };
443
444 static void rcu_sync_torture_deferred_free(struct rcu_torture *p)
445 {
446 int i;
447 struct rcu_torture *rp;
448 struct rcu_torture *rp1;
449
450 cur_ops->sync();
451 list_add(&p->rtort_free, &rcu_torture_removed);
452 list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) {
453 i = rp->rtort_pipe_count;
454 if (i > RCU_TORTURE_PIPE_LEN)
455 i = RCU_TORTURE_PIPE_LEN;
456 atomic_inc(&rcu_torture_wcount[i]);
457 if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
458 rp->rtort_mbtest = 0;
459 list_del(&rp->rtort_free);
460 rcu_torture_free(rp);
461 }
462 }
463 }
464
465 static void rcu_sync_torture_init(void)
466 {
467 INIT_LIST_HEAD(&rcu_torture_removed);
468 }
469
470 static struct rcu_torture_ops rcu_sync_ops = {
471 .init = rcu_sync_torture_init,
472 .cleanup = NULL,
473 .readlock = rcu_torture_read_lock,
474 .read_delay = rcu_read_delay,
475 .readunlock = rcu_torture_read_unlock,
476 .completed = rcu_torture_completed,
477 .deferred_free = rcu_sync_torture_deferred_free,
478 .sync = synchronize_rcu,
479 .call = NULL,
480 .cb_barrier = NULL,
481 .fqs = rcu_force_quiescent_state,
482 .stats = NULL,
483 .irq_capable = 1,
484 .can_boost = rcu_can_boost(),
485 .name = "rcu_sync"
486 };
487
488 static struct rcu_torture_ops rcu_expedited_ops = {
489 .init = rcu_sync_torture_init,
490 .cleanup = NULL,
491 .readlock = rcu_torture_read_lock,
492 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
493 .readunlock = rcu_torture_read_unlock,
494 .completed = rcu_no_completed,
495 .deferred_free = rcu_sync_torture_deferred_free,
496 .sync = synchronize_rcu_expedited,
497 .call = NULL,
498 .cb_barrier = NULL,
499 .fqs = rcu_force_quiescent_state,
500 .stats = NULL,
501 .irq_capable = 1,
502 .can_boost = rcu_can_boost(),
503 .name = "rcu_expedited"
504 };
505
506 /*
507 * Definitions for rcu_bh torture testing.
508 */
509
510 static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH)
511 {
512 rcu_read_lock_bh();
513 return 0;
514 }
515
516 static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH)
517 {
518 rcu_read_unlock_bh();
519 }
520
521 static int rcu_bh_torture_completed(void)
522 {
523 return rcu_batches_completed_bh();
524 }
525
526 static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
527 {
528 call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
529 }
530
531 static struct rcu_torture_ops rcu_bh_ops = {
532 .init = NULL,
533 .cleanup = NULL,
534 .readlock = rcu_bh_torture_read_lock,
535 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
536 .readunlock = rcu_bh_torture_read_unlock,
537 .completed = rcu_bh_torture_completed,
538 .deferred_free = rcu_bh_torture_deferred_free,
539 .sync = synchronize_rcu_bh,
540 .call = call_rcu_bh,
541 .cb_barrier = rcu_barrier_bh,
542 .fqs = rcu_bh_force_quiescent_state,
543 .stats = NULL,
544 .irq_capable = 1,
545 .name = "rcu_bh"
546 };
547
548 static struct rcu_torture_ops rcu_bh_sync_ops = {
549 .init = rcu_sync_torture_init,
550 .cleanup = NULL,
551 .readlock = rcu_bh_torture_read_lock,
552 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
553 .readunlock = rcu_bh_torture_read_unlock,
554 .completed = rcu_bh_torture_completed,
555 .deferred_free = rcu_sync_torture_deferred_free,
556 .sync = synchronize_rcu_bh,
557 .call = NULL,
558 .cb_barrier = NULL,
559 .fqs = rcu_bh_force_quiescent_state,
560 .stats = NULL,
561 .irq_capable = 1,
562 .name = "rcu_bh_sync"
563 };
564
565 static struct rcu_torture_ops rcu_bh_expedited_ops = {
566 .init = rcu_sync_torture_init,
567 .cleanup = NULL,
568 .readlock = rcu_bh_torture_read_lock,
569 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
570 .readunlock = rcu_bh_torture_read_unlock,
571 .completed = rcu_bh_torture_completed,
572 .deferred_free = rcu_sync_torture_deferred_free,
573 .sync = synchronize_rcu_bh_expedited,
574 .call = NULL,
575 .cb_barrier = NULL,
576 .fqs = rcu_bh_force_quiescent_state,
577 .stats = NULL,
578 .irq_capable = 1,
579 .name = "rcu_bh_expedited"
580 };
581
582 /*
583 * Definitions for srcu torture testing.
584 */
585
586 static struct srcu_struct srcu_ctl;
587
588 static void srcu_torture_init(void)
589 {
590 init_srcu_struct(&srcu_ctl);
591 rcu_sync_torture_init();
592 }
593
594 static void srcu_torture_cleanup(void)
595 {
596 synchronize_srcu(&srcu_ctl);
597 cleanup_srcu_struct(&srcu_ctl);
598 }
599
600 static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
601 {
602 return srcu_read_lock(&srcu_ctl);
603 }
604
605 static void srcu_read_delay(struct rcu_random_state *rrsp)
606 {
607 long delay;
608 const long uspertick = 1000000 / HZ;
609 const long longdelay = 10;
610
611 /* We want there to be long-running readers, but not all the time. */
612
613 delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick);
614 if (!delay)
615 schedule_timeout_interruptible(longdelay);
616 else
617 rcu_read_delay(rrsp);
618 }
619
620 static void srcu_torture_read_unlock(int idx) __releases(&srcu_ctl)
621 {
622 srcu_read_unlock(&srcu_ctl, idx);
623 }
624
625 static int srcu_torture_completed(void)
626 {
627 return srcu_batches_completed(&srcu_ctl);
628 }
629
630 static void srcu_torture_deferred_free(struct rcu_torture *rp)
631 {
632 call_srcu(&srcu_ctl, &rp->rtort_rcu, rcu_torture_cb);
633 }
634
635 static void srcu_torture_synchronize(void)
636 {
637 synchronize_srcu(&srcu_ctl);
638 }
639
640 static void srcu_torture_call(struct rcu_head *head,
641 void (*func)(struct rcu_head *head))
642 {
643 call_srcu(&srcu_ctl, head, func);
644 }
645
646 static void srcu_torture_barrier(void)
647 {
648 srcu_barrier(&srcu_ctl);
649 }
650
651 static int srcu_torture_stats(char *page)
652 {
653 int cnt = 0;
654 int cpu;
655 int idx = srcu_ctl.completed & 0x1;
656
657 cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):",
658 torture_type, TORTURE_FLAG, idx);
659 for_each_possible_cpu(cpu) {
660 cnt += sprintf(&page[cnt], " %d(%lu,%lu)", cpu,
661 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx],
662 per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]);
663 }
664 cnt += sprintf(&page[cnt], "\n");
665 return cnt;
666 }
667
668 static struct rcu_torture_ops srcu_ops = {
669 .init = srcu_torture_init,
670 .cleanup = srcu_torture_cleanup,
671 .readlock = srcu_torture_read_lock,
672 .read_delay = srcu_read_delay,
673 .readunlock = srcu_torture_read_unlock,
674 .completed = srcu_torture_completed,
675 .deferred_free = srcu_torture_deferred_free,
676 .sync = srcu_torture_synchronize,
677 .call = srcu_torture_call,
678 .cb_barrier = srcu_torture_barrier,
679 .stats = srcu_torture_stats,
680 .name = "srcu"
681 };
682
683 static struct rcu_torture_ops srcu_sync_ops = {
684 .init = srcu_torture_init,
685 .cleanup = srcu_torture_cleanup,
686 .readlock = srcu_torture_read_lock,
687 .read_delay = srcu_read_delay,
688 .readunlock = srcu_torture_read_unlock,
689 .completed = srcu_torture_completed,
690 .deferred_free = rcu_sync_torture_deferred_free,
691 .sync = srcu_torture_synchronize,
692 .call = NULL,
693 .cb_barrier = NULL,
694 .stats = srcu_torture_stats,
695 .name = "srcu_sync"
696 };
697
698 static int srcu_torture_read_lock_raw(void) __acquires(&srcu_ctl)
699 {
700 return srcu_read_lock_raw(&srcu_ctl);
701 }
702
703 static void srcu_torture_read_unlock_raw(int idx) __releases(&srcu_ctl)
704 {
705 srcu_read_unlock_raw(&srcu_ctl, idx);
706 }
707
708 static struct rcu_torture_ops srcu_raw_ops = {
709 .init = srcu_torture_init,
710 .cleanup = srcu_torture_cleanup,
711 .readlock = srcu_torture_read_lock_raw,
712 .read_delay = srcu_read_delay,
713 .readunlock = srcu_torture_read_unlock_raw,
714 .completed = srcu_torture_completed,
715 .deferred_free = srcu_torture_deferred_free,
716 .sync = srcu_torture_synchronize,
717 .call = NULL,
718 .cb_barrier = NULL,
719 .stats = srcu_torture_stats,
720 .name = "srcu_raw"
721 };
722
723 static struct rcu_torture_ops srcu_raw_sync_ops = {
724 .init = srcu_torture_init,
725 .cleanup = srcu_torture_cleanup,
726 .readlock = srcu_torture_read_lock_raw,
727 .read_delay = srcu_read_delay,
728 .readunlock = srcu_torture_read_unlock_raw,
729 .completed = srcu_torture_completed,
730 .deferred_free = rcu_sync_torture_deferred_free,
731 .sync = srcu_torture_synchronize,
732 .call = NULL,
733 .cb_barrier = NULL,
734 .stats = srcu_torture_stats,
735 .name = "srcu_raw_sync"
736 };
737
738 static void srcu_torture_synchronize_expedited(void)
739 {
740 synchronize_srcu_expedited(&srcu_ctl);
741 }
742
743 static struct rcu_torture_ops srcu_expedited_ops = {
744 .init = srcu_torture_init,
745 .cleanup = srcu_torture_cleanup,
746 .readlock = srcu_torture_read_lock,
747 .read_delay = srcu_read_delay,
748 .readunlock = srcu_torture_read_unlock,
749 .completed = srcu_torture_completed,
750 .deferred_free = rcu_sync_torture_deferred_free,
751 .sync = srcu_torture_synchronize_expedited,
752 .call = NULL,
753 .cb_barrier = NULL,
754 .stats = srcu_torture_stats,
755 .name = "srcu_expedited"
756 };
757
758 /*
759 * Definitions for sched torture testing.
760 */
761
762 static int sched_torture_read_lock(void)
763 {
764 preempt_disable();
765 return 0;
766 }
767
768 static void sched_torture_read_unlock(int idx)
769 {
770 preempt_enable();
771 }
772
773 static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
774 {
775 call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
776 }
777
778 static struct rcu_torture_ops sched_ops = {
779 .init = rcu_sync_torture_init,
780 .cleanup = NULL,
781 .readlock = sched_torture_read_lock,
782 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
783 .readunlock = sched_torture_read_unlock,
784 .completed = rcu_no_completed,
785 .deferred_free = rcu_sched_torture_deferred_free,
786 .sync = synchronize_sched,
787 .cb_barrier = rcu_barrier_sched,
788 .fqs = rcu_sched_force_quiescent_state,
789 .stats = NULL,
790 .irq_capable = 1,
791 .name = "sched"
792 };
793
794 static struct rcu_torture_ops sched_sync_ops = {
795 .init = rcu_sync_torture_init,
796 .cleanup = NULL,
797 .readlock = sched_torture_read_lock,
798 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
799 .readunlock = sched_torture_read_unlock,
800 .completed = rcu_no_completed,
801 .deferred_free = rcu_sync_torture_deferred_free,
802 .sync = synchronize_sched,
803 .cb_barrier = NULL,
804 .fqs = rcu_sched_force_quiescent_state,
805 .stats = NULL,
806 .name = "sched_sync"
807 };
808
809 static struct rcu_torture_ops sched_expedited_ops = {
810 .init = rcu_sync_torture_init,
811 .cleanup = NULL,
812 .readlock = sched_torture_read_lock,
813 .read_delay = rcu_read_delay, /* just reuse rcu's version. */
814 .readunlock = sched_torture_read_unlock,
815 .completed = rcu_no_completed,
816 .deferred_free = rcu_sync_torture_deferred_free,
817 .sync = synchronize_sched_expedited,
818 .cb_barrier = NULL,
819 .fqs = rcu_sched_force_quiescent_state,
820 .stats = NULL,
821 .irq_capable = 1,
822 .name = "sched_expedited"
823 };
824
825 /*
826 * RCU torture priority-boost testing. Runs one real-time thread per
827 * CPU for moderate bursts, repeatedly registering RCU callbacks and
828 * spinning waiting for them to be invoked. If a given callback takes
829 * too long to be invoked, we assume that priority inversion has occurred.
830 */
831
832 struct rcu_boost_inflight {
833 struct rcu_head rcu;
834 int inflight;
835 };
836
837 static void rcu_torture_boost_cb(struct rcu_head *head)
838 {
839 struct rcu_boost_inflight *rbip =
840 container_of(head, struct rcu_boost_inflight, rcu);
841
842 smp_mb(); /* Ensure RCU-core accesses precede clearing ->inflight */
843 rbip->inflight = 0;
844 }
845
846 static int rcu_torture_boost(void *arg)
847 {
848 unsigned long call_rcu_time;
849 unsigned long endtime;
850 unsigned long oldstarttime;
851 struct rcu_boost_inflight rbi = { .inflight = 0 };
852 struct sched_param sp;
853
854 VERBOSE_PRINTK_STRING("rcu_torture_boost started");
855
856 /* Set real-time priority. */
857 sp.sched_priority = 1;
858 if (sched_setscheduler(current, SCHED_FIFO, &sp) < 0) {
859 VERBOSE_PRINTK_STRING("rcu_torture_boost RT prio failed!");
860 n_rcu_torture_boost_rterror++;
861 }
862
863 init_rcu_head_on_stack(&rbi.rcu);
864 /* Each pass through the following loop does one boost-test cycle. */
865 do {
866 /* Wait for the next test interval. */
867 oldstarttime = boost_starttime;
868 while (ULONG_CMP_LT(jiffies, oldstarttime)) {
869 schedule_timeout_uninterruptible(1);
870 rcu_stutter_wait("rcu_torture_boost");
871 if (kthread_should_stop() ||
872 fullstop != FULLSTOP_DONTSTOP)
873 goto checkwait;
874 }
875
876 /* Do one boost-test interval. */
877 endtime = oldstarttime + test_boost_duration * HZ;
878 call_rcu_time = jiffies;
879 while (ULONG_CMP_LT(jiffies, endtime)) {
880 /* If we don't have a callback in flight, post one. */
881 if (!rbi.inflight) {
882 smp_mb(); /* RCU core before ->inflight = 1. */
883 rbi.inflight = 1;
884 call_rcu(&rbi.rcu, rcu_torture_boost_cb);
885 if (jiffies - call_rcu_time >
886 test_boost_duration * HZ - HZ / 2) {
887 VERBOSE_PRINTK_STRING("rcu_torture_boost boosting failed");
888 n_rcu_torture_boost_failure++;
889 }
890 call_rcu_time = jiffies;
891 }
892 cond_resched();
893 rcu_stutter_wait("rcu_torture_boost");
894 if (kthread_should_stop() ||
895 fullstop != FULLSTOP_DONTSTOP)
896 goto checkwait;
897 }
898
899 /*
900 * Set the start time of the next test interval.
901 * Yes, this is vulnerable to long delays, but such
902 * delays simply cause a false negative for the next
903 * interval. Besides, we are running at RT priority,
904 * so delays should be relatively rare.
905 */
906 while (oldstarttime == boost_starttime &&
907 !kthread_should_stop()) {
908 if (mutex_trylock(&boost_mutex)) {
909 boost_starttime = jiffies +
910 test_boost_interval * HZ;
911 n_rcu_torture_boosts++;
912 mutex_unlock(&boost_mutex);
913 break;
914 }
915 schedule_timeout_uninterruptible(1);
916 }
917
918 /* Go do the stutter. */
919 checkwait: rcu_stutter_wait("rcu_torture_boost");
920 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
921
922 /* Clean up and exit. */
923 VERBOSE_PRINTK_STRING("rcu_torture_boost task stopping");
924 rcutorture_shutdown_absorb("rcu_torture_boost");
925 while (!kthread_should_stop() || rbi.inflight)
926 schedule_timeout_uninterruptible(1);
927 smp_mb(); /* order accesses to ->inflight before stack-frame death. */
928 destroy_rcu_head_on_stack(&rbi.rcu);
929 return 0;
930 }
931
932 /*
933 * RCU torture force-quiescent-state kthread. Repeatedly induces
934 * bursts of calls to force_quiescent_state(), increasing the probability
935 * of occurrence of some important types of race conditions.
936 */
937 static int
938 rcu_torture_fqs(void *arg)
939 {
940 unsigned long fqs_resume_time;
941 int fqs_burst_remaining;
942
943 VERBOSE_PRINTK_STRING("rcu_torture_fqs task started");
944 do {
945 fqs_resume_time = jiffies + fqs_stutter * HZ;
946 while (ULONG_CMP_LT(jiffies, fqs_resume_time) &&
947 !kthread_should_stop()) {
948 schedule_timeout_interruptible(1);
949 }
950 fqs_burst_remaining = fqs_duration;
951 while (fqs_burst_remaining > 0 &&
952 !kthread_should_stop()) {
953 cur_ops->fqs();
954 udelay(fqs_holdoff);
955 fqs_burst_remaining -= fqs_holdoff;
956 }
957 rcu_stutter_wait("rcu_torture_fqs");
958 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
959 VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping");
960 rcutorture_shutdown_absorb("rcu_torture_fqs");
961 while (!kthread_should_stop())
962 schedule_timeout_uninterruptible(1);
963 return 0;
964 }
965
966 /*
967 * RCU torture writer kthread. Repeatedly substitutes a new structure
968 * for that pointed to by rcu_torture_current, freeing the old structure
969 * after a series of grace periods (the "pipeline").
970 */
971 static int
972 rcu_torture_writer(void *arg)
973 {
974 int i;
975 long oldbatch = rcu_batches_completed();
976 struct rcu_torture *rp;
977 struct rcu_torture *old_rp;
978 static DEFINE_RCU_RANDOM(rand);
979
980 VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
981 set_user_nice(current, 19);
982
983 do {
984 schedule_timeout_uninterruptible(1);
985 rp = rcu_torture_alloc();
986 if (rp == NULL)
987 continue;
988 rp->rtort_pipe_count = 0;
989 udelay(rcu_random(&rand) & 0x3ff);
990 old_rp = rcu_dereference_check(rcu_torture_current,
991 current == writer_task);
992 rp->rtort_mbtest = 1;
993 rcu_assign_pointer(rcu_torture_current, rp);
994 smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
995 if (old_rp) {
996 i = old_rp->rtort_pipe_count;
997 if (i > RCU_TORTURE_PIPE_LEN)
998 i = RCU_TORTURE_PIPE_LEN;
999 atomic_inc(&rcu_torture_wcount[i]);
1000 old_rp->rtort_pipe_count++;
1001 cur_ops->deferred_free(old_rp);
1002 }
1003 rcutorture_record_progress(++rcu_torture_current_version);
1004 oldbatch = cur_ops->completed();
1005 rcu_stutter_wait("rcu_torture_writer");
1006 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1007 VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
1008 rcutorture_shutdown_absorb("rcu_torture_writer");
1009 while (!kthread_should_stop())
1010 schedule_timeout_uninterruptible(1);
1011 return 0;
1012 }
1013
1014 /*
1015 * RCU torture fake writer kthread. Repeatedly calls sync, with a random
1016 * delay between calls.
1017 */
1018 static int
1019 rcu_torture_fakewriter(void *arg)
1020 {
1021 DEFINE_RCU_RANDOM(rand);
1022
1023 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started");
1024 set_user_nice(current, 19);
1025
1026 do {
1027 schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
1028 udelay(rcu_random(&rand) & 0x3ff);
1029 if (cur_ops->cb_barrier != NULL &&
1030 rcu_random(&rand) % (nfakewriters * 8) == 0)
1031 cur_ops->cb_barrier();
1032 else
1033 cur_ops->sync();
1034 rcu_stutter_wait("rcu_torture_fakewriter");
1035 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1036
1037 VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
1038 rcutorture_shutdown_absorb("rcu_torture_fakewriter");
1039 while (!kthread_should_stop())
1040 schedule_timeout_uninterruptible(1);
1041 return 0;
1042 }
1043
1044 void rcutorture_trace_dump(void)
1045 {
1046 static atomic_t beenhere = ATOMIC_INIT(0);
1047
1048 if (atomic_read(&beenhere))
1049 return;
1050 if (atomic_xchg(&beenhere, 1) != 0)
1051 return;
1052 do_trace_rcu_torture_read(cur_ops->name, (struct rcu_head *)~0UL);
1053 ftrace_dump(DUMP_ALL);
1054 }
1055
1056 /*
1057 * RCU torture reader from timer handler. Dereferences rcu_torture_current,
1058 * incrementing the corresponding element of the pipeline array. The
1059 * counter in the element should never be greater than 1, otherwise, the
1060 * RCU implementation is broken.
1061 */
1062 static void rcu_torture_timer(unsigned long unused)
1063 {
1064 int idx;
1065 int completed;
1066 static DEFINE_RCU_RANDOM(rand);
1067 static DEFINE_SPINLOCK(rand_lock);
1068 struct rcu_torture *p;
1069 int pipe_count;
1070
1071 idx = cur_ops->readlock();
1072 completed = cur_ops->completed();
1073 p = rcu_dereference_check(rcu_torture_current,
1074 rcu_read_lock_bh_held() ||
1075 rcu_read_lock_sched_held() ||
1076 srcu_read_lock_held(&srcu_ctl));
1077 if (p == NULL) {
1078 /* Leave because rcu_torture_writer is not yet underway */
1079 cur_ops->readunlock(idx);
1080 return;
1081 }
1082 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu);
1083 if (p->rtort_mbtest == 0)
1084 atomic_inc(&n_rcu_torture_mberror);
1085 spin_lock(&rand_lock);
1086 cur_ops->read_delay(&rand);
1087 n_rcu_torture_timers++;
1088 spin_unlock(&rand_lock);
1089 preempt_disable();
1090 pipe_count = p->rtort_pipe_count;
1091 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1092 /* Should not happen, but... */
1093 pipe_count = RCU_TORTURE_PIPE_LEN;
1094 }
1095 if (pipe_count > 1)
1096 rcutorture_trace_dump();
1097 __this_cpu_inc(rcu_torture_count[pipe_count]);
1098 completed = cur_ops->completed() - completed;
1099 if (completed > RCU_TORTURE_PIPE_LEN) {
1100 /* Should not happen, but... */
1101 completed = RCU_TORTURE_PIPE_LEN;
1102 }
1103 __this_cpu_inc(rcu_torture_batch[completed]);
1104 preempt_enable();
1105 cur_ops->readunlock(idx);
1106 }
1107
1108 /*
1109 * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
1110 * incrementing the corresponding element of the pipeline array. The
1111 * counter in the element should never be greater than 1, otherwise, the
1112 * RCU implementation is broken.
1113 */
1114 static int
1115 rcu_torture_reader(void *arg)
1116 {
1117 int completed;
1118 int idx;
1119 DEFINE_RCU_RANDOM(rand);
1120 struct rcu_torture *p;
1121 int pipe_count;
1122 struct timer_list t;
1123
1124 VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
1125 set_user_nice(current, 19);
1126 if (irqreader && cur_ops->irq_capable)
1127 setup_timer_on_stack(&t, rcu_torture_timer, 0);
1128
1129 do {
1130 if (irqreader && cur_ops->irq_capable) {
1131 if (!timer_pending(&t))
1132 mod_timer(&t, jiffies + 1);
1133 }
1134 idx = cur_ops->readlock();
1135 completed = cur_ops->completed();
1136 p = rcu_dereference_check(rcu_torture_current,
1137 rcu_read_lock_bh_held() ||
1138 rcu_read_lock_sched_held() ||
1139 srcu_read_lock_held(&srcu_ctl));
1140 if (p == NULL) {
1141 /* Wait for rcu_torture_writer to get underway */
1142 cur_ops->readunlock(idx);
1143 schedule_timeout_interruptible(HZ);
1144 continue;
1145 }
1146 do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu);
1147 if (p->rtort_mbtest == 0)
1148 atomic_inc(&n_rcu_torture_mberror);
1149 cur_ops->read_delay(&rand);
1150 preempt_disable();
1151 pipe_count = p->rtort_pipe_count;
1152 if (pipe_count > RCU_TORTURE_PIPE_LEN) {
1153 /* Should not happen, but... */
1154 pipe_count = RCU_TORTURE_PIPE_LEN;
1155 }
1156 if (pipe_count > 1)
1157 rcutorture_trace_dump();
1158 __this_cpu_inc(rcu_torture_count[pipe_count]);
1159 completed = cur_ops->completed() - completed;
1160 if (completed > RCU_TORTURE_PIPE_LEN) {
1161 /* Should not happen, but... */
1162 completed = RCU_TORTURE_PIPE_LEN;
1163 }
1164 __this_cpu_inc(rcu_torture_batch[completed]);
1165 preempt_enable();
1166 cur_ops->readunlock(idx);
1167 schedule();
1168 rcu_stutter_wait("rcu_torture_reader");
1169 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1170 VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
1171 rcutorture_shutdown_absorb("rcu_torture_reader");
1172 if (irqreader && cur_ops->irq_capable)
1173 del_timer_sync(&t);
1174 while (!kthread_should_stop())
1175 schedule_timeout_uninterruptible(1);
1176 return 0;
1177 }
1178
1179 /*
1180 * Create an RCU-torture statistics message in the specified buffer.
1181 */
1182 static int
1183 rcu_torture_printk(char *page)
1184 {
1185 int cnt = 0;
1186 int cpu;
1187 int i;
1188 long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1189 long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
1190
1191 for_each_possible_cpu(cpu) {
1192 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1193 pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
1194 batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
1195 }
1196 }
1197 for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
1198 if (pipesummary[i] != 0)
1199 break;
1200 }
1201 cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG);
1202 cnt += sprintf(&page[cnt],
1203 "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d "
1204 "rtmbe: %d rtbke: %ld rtbre: %ld "
1205 "rtbf: %ld rtb: %ld nt: %ld "
1206 "onoff: %ld/%ld:%ld/%ld "
1207 "barrier: %ld/%ld:%ld",
1208 rcu_torture_current,
1209 rcu_torture_current_version,
1210 list_empty(&rcu_torture_freelist),
1211 atomic_read(&n_rcu_torture_alloc),
1212 atomic_read(&n_rcu_torture_alloc_fail),
1213 atomic_read(&n_rcu_torture_free),
1214 atomic_read(&n_rcu_torture_mberror),
1215 n_rcu_torture_boost_ktrerror,
1216 n_rcu_torture_boost_rterror,
1217 n_rcu_torture_boost_failure,
1218 n_rcu_torture_boosts,
1219 n_rcu_torture_timers,
1220 n_online_successes,
1221 n_online_attempts,
1222 n_offline_successes,
1223 n_offline_attempts,
1224 n_barrier_successes,
1225 n_barrier_attempts,
1226 n_rcu_torture_barrier_error);
1227 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1228 if (atomic_read(&n_rcu_torture_mberror) != 0 ||
1229 n_rcu_torture_barrier_error != 0 ||
1230 n_rcu_torture_boost_ktrerror != 0 ||
1231 n_rcu_torture_boost_rterror != 0 ||
1232 n_rcu_torture_boost_failure != 0 ||
1233 i > 1) {
1234 cnt += sprintf(&page[cnt], "!!! ");
1235 atomic_inc(&n_rcu_torture_error);
1236 WARN_ON_ONCE(1);
1237 }
1238 cnt += sprintf(&page[cnt], "Reader Pipe: ");
1239 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1240 cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
1241 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1242 cnt += sprintf(&page[cnt], "Reader Batch: ");
1243 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1244 cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
1245 cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG);
1246 cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
1247 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1248 cnt += sprintf(&page[cnt], " %d",
1249 atomic_read(&rcu_torture_wcount[i]));
1250 }
1251 cnt += sprintf(&page[cnt], "\n");
1252 if (cur_ops->stats)
1253 cnt += cur_ops->stats(&page[cnt]);
1254 return cnt;
1255 }
1256
1257 /*
1258 * Print torture statistics. Caller must ensure that there is only
1259 * one call to this function at a given time!!! This is normally
1260 * accomplished by relying on the module system to only have one copy
1261 * of the module loaded, and then by giving the rcu_torture_stats
1262 * kthread full control (or the init/cleanup functions when rcu_torture_stats
1263 * thread is not running).
1264 */
1265 static void
1266 rcu_torture_stats_print(void)
1267 {
1268 int cnt;
1269
1270 cnt = rcu_torture_printk(printk_buf);
1271 printk(KERN_ALERT "%s", printk_buf);
1272 }
1273
1274 /*
1275 * Periodically prints torture statistics, if periodic statistics printing
1276 * was specified via the stat_interval module parameter.
1277 *
1278 * No need to worry about fullstop here, since this one doesn't reference
1279 * volatile state or register callbacks.
1280 */
1281 static int
1282 rcu_torture_stats(void *arg)
1283 {
1284 VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
1285 do {
1286 schedule_timeout_interruptible(stat_interval * HZ);
1287 rcu_torture_stats_print();
1288 rcutorture_shutdown_absorb("rcu_torture_stats");
1289 } while (!kthread_should_stop());
1290 VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
1291 return 0;
1292 }
1293
1294 static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
1295
1296 /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
1297 * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
1298 */
1299 static void rcu_torture_shuffle_tasks(void)
1300 {
1301 int i;
1302
1303 cpumask_setall(shuffle_tmp_mask);
1304 get_online_cpus();
1305
1306 /* No point in shuffling if there is only one online CPU (ex: UP) */
1307 if (num_online_cpus() == 1) {
1308 put_online_cpus();
1309 return;
1310 }
1311
1312 if (rcu_idle_cpu != -1)
1313 cpumask_clear_cpu(rcu_idle_cpu, shuffle_tmp_mask);
1314
1315 set_cpus_allowed_ptr(current, shuffle_tmp_mask);
1316
1317 if (reader_tasks) {
1318 for (i = 0; i < nrealreaders; i++)
1319 if (reader_tasks[i])
1320 set_cpus_allowed_ptr(reader_tasks[i],
1321 shuffle_tmp_mask);
1322 }
1323
1324 if (fakewriter_tasks) {
1325 for (i = 0; i < nfakewriters; i++)
1326 if (fakewriter_tasks[i])
1327 set_cpus_allowed_ptr(fakewriter_tasks[i],
1328 shuffle_tmp_mask);
1329 }
1330
1331 if (writer_task)
1332 set_cpus_allowed_ptr(writer_task, shuffle_tmp_mask);
1333
1334 if (stats_task)
1335 set_cpus_allowed_ptr(stats_task, shuffle_tmp_mask);
1336
1337 if (rcu_idle_cpu == -1)
1338 rcu_idle_cpu = num_online_cpus() - 1;
1339 else
1340 rcu_idle_cpu--;
1341
1342 put_online_cpus();
1343 }
1344
1345 /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
1346 * system to become idle at a time and cut off its timer ticks. This is meant
1347 * to test the support for such tickless idle CPU in RCU.
1348 */
1349 static int
1350 rcu_torture_shuffle(void *arg)
1351 {
1352 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
1353 do {
1354 schedule_timeout_interruptible(shuffle_interval * HZ);
1355 rcu_torture_shuffle_tasks();
1356 rcutorture_shutdown_absorb("rcu_torture_shuffle");
1357 } while (!kthread_should_stop());
1358 VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
1359 return 0;
1360 }
1361
1362 /* Cause the rcutorture test to "stutter", starting and stopping all
1363 * threads periodically.
1364 */
1365 static int
1366 rcu_torture_stutter(void *arg)
1367 {
1368 VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
1369 do {
1370 schedule_timeout_interruptible(stutter * HZ);
1371 stutter_pause_test = 1;
1372 if (!kthread_should_stop())
1373 schedule_timeout_interruptible(stutter * HZ);
1374 stutter_pause_test = 0;
1375 rcutorture_shutdown_absorb("rcu_torture_stutter");
1376 } while (!kthread_should_stop());
1377 VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
1378 return 0;
1379 }
1380
1381 static inline void
1382 rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, char *tag)
1383 {
1384 printk(KERN_ALERT "%s" TORTURE_FLAG
1385 "--- %s: nreaders=%d nfakewriters=%d "
1386 "stat_interval=%d verbose=%d test_no_idle_hz=%d "
1387 "shuffle_interval=%d stutter=%d irqreader=%d "
1388 "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
1389 "test_boost=%d/%d test_boost_interval=%d "
1390 "test_boost_duration=%d shutdown_secs=%d "
1391 "onoff_interval=%d onoff_holdoff=%d\n",
1392 torture_type, tag, nrealreaders, nfakewriters,
1393 stat_interval, verbose, test_no_idle_hz, shuffle_interval,
1394 stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
1395 test_boost, cur_ops->can_boost,
1396 test_boost_interval, test_boost_duration, shutdown_secs,
1397 onoff_interval, onoff_holdoff);
1398 }
1399
1400 static struct notifier_block rcutorture_shutdown_nb = {
1401 .notifier_call = rcutorture_shutdown_notify,
1402 };
1403
1404 static void rcutorture_booster_cleanup(int cpu)
1405 {
1406 struct task_struct *t;
1407
1408 if (boost_tasks[cpu] == NULL)
1409 return;
1410 mutex_lock(&boost_mutex);
1411 VERBOSE_PRINTK_STRING("Stopping rcu_torture_boost task");
1412 t = boost_tasks[cpu];
1413 boost_tasks[cpu] = NULL;
1414 mutex_unlock(&boost_mutex);
1415
1416 /* This must be outside of the mutex, otherwise deadlock! */
1417 kthread_stop(t);
1418 boost_tasks[cpu] = NULL;
1419 }
1420
1421 static int rcutorture_booster_init(int cpu)
1422 {
1423 int retval;
1424
1425 if (boost_tasks[cpu] != NULL)
1426 return 0; /* Already created, nothing more to do. */
1427
1428 /* Don't allow time recalculation while creating a new task. */
1429 mutex_lock(&boost_mutex);
1430 VERBOSE_PRINTK_STRING("Creating rcu_torture_boost task");
1431 boost_tasks[cpu] = kthread_create_on_node(rcu_torture_boost, NULL,
1432 cpu_to_node(cpu),
1433 "rcu_torture_boost");
1434 if (IS_ERR(boost_tasks[cpu])) {
1435 retval = PTR_ERR(boost_tasks[cpu]);
1436 VERBOSE_PRINTK_STRING("rcu_torture_boost task create failed");
1437 n_rcu_torture_boost_ktrerror++;
1438 boost_tasks[cpu] = NULL;
1439 mutex_unlock(&boost_mutex);
1440 return retval;
1441 }
1442 kthread_bind(boost_tasks[cpu], cpu);
1443 wake_up_process(boost_tasks[cpu]);
1444 mutex_unlock(&boost_mutex);
1445 return 0;
1446 }
1447
1448 /*
1449 * Cause the rcutorture test to shutdown the system after the test has
1450 * run for the time specified by the shutdown_secs module parameter.
1451 */
1452 static int
1453 rcu_torture_shutdown(void *arg)
1454 {
1455 long delta;
1456 unsigned long jiffies_snap;
1457
1458 VERBOSE_PRINTK_STRING("rcu_torture_shutdown task started");
1459 jiffies_snap = ACCESS_ONCE(jiffies);
1460 while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
1461 !kthread_should_stop()) {
1462 delta = shutdown_time - jiffies_snap;
1463 if (verbose)
1464 printk(KERN_ALERT "%s" TORTURE_FLAG
1465 "rcu_torture_shutdown task: %lu "
1466 "jiffies remaining\n",
1467 torture_type, delta);
1468 schedule_timeout_interruptible(delta);
1469 jiffies_snap = ACCESS_ONCE(jiffies);
1470 }
1471 if (kthread_should_stop()) {
1472 VERBOSE_PRINTK_STRING("rcu_torture_shutdown task stopping");
1473 return 0;
1474 }
1475
1476 /* OK, shut down the system. */
1477
1478 VERBOSE_PRINTK_STRING("rcu_torture_shutdown task shutting down system");
1479 shutdown_task = NULL; /* Avoid self-kill deadlock. */
1480 rcu_torture_cleanup(); /* Get the success/failure message. */
1481 kernel_power_off(); /* Shut down the system. */
1482 return 0;
1483 }
1484
1485 #ifdef CONFIG_HOTPLUG_CPU
1486
1487 /*
1488 * Execute random CPU-hotplug operations at the interval specified
1489 * by the onoff_interval.
1490 */
1491 static int __cpuinit
1492 rcu_torture_onoff(void *arg)
1493 {
1494 int cpu;
1495 int maxcpu = -1;
1496 DEFINE_RCU_RANDOM(rand);
1497
1498 VERBOSE_PRINTK_STRING("rcu_torture_onoff task started");
1499 for_each_online_cpu(cpu)
1500 maxcpu = cpu;
1501 WARN_ON(maxcpu < 0);
1502 if (onoff_holdoff > 0) {
1503 VERBOSE_PRINTK_STRING("rcu_torture_onoff begin holdoff");
1504 schedule_timeout_interruptible(onoff_holdoff * HZ);
1505 VERBOSE_PRINTK_STRING("rcu_torture_onoff end holdoff");
1506 }
1507 while (!kthread_should_stop()) {
1508 cpu = (rcu_random(&rand) >> 4) % (maxcpu + 1);
1509 if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) {
1510 if (verbose)
1511 printk(KERN_ALERT "%s" TORTURE_FLAG
1512 "rcu_torture_onoff task: offlining %d\n",
1513 torture_type, cpu);
1514 n_offline_attempts++;
1515 if (cpu_down(cpu) == 0) {
1516 if (verbose)
1517 printk(KERN_ALERT "%s" TORTURE_FLAG
1518 "rcu_torture_onoff task: "
1519 "offlined %d\n",
1520 torture_type, cpu);
1521 n_offline_successes++;
1522 }
1523 } else if (cpu_is_hotpluggable(cpu)) {
1524 if (verbose)
1525 printk(KERN_ALERT "%s" TORTURE_FLAG
1526 "rcu_torture_onoff task: onlining %d\n",
1527 torture_type, cpu);
1528 n_online_attempts++;
1529 if (cpu_up(cpu) == 0) {
1530 if (verbose)
1531 printk(KERN_ALERT "%s" TORTURE_FLAG
1532 "rcu_torture_onoff task: "
1533 "onlined %d\n",
1534 torture_type, cpu);
1535 n_online_successes++;
1536 }
1537 }
1538 schedule_timeout_interruptible(onoff_interval * HZ);
1539 }
1540 VERBOSE_PRINTK_STRING("rcu_torture_onoff task stopping");
1541 return 0;
1542 }
1543
1544 static int __cpuinit
1545 rcu_torture_onoff_init(void)
1546 {
1547 int ret;
1548
1549 if (onoff_interval <= 0)
1550 return 0;
1551 onoff_task = kthread_run(rcu_torture_onoff, NULL, "rcu_torture_onoff");
1552 if (IS_ERR(onoff_task)) {
1553 ret = PTR_ERR(onoff_task);
1554 onoff_task = NULL;
1555 return ret;
1556 }
1557 return 0;
1558 }
1559
1560 static void rcu_torture_onoff_cleanup(void)
1561 {
1562 if (onoff_task == NULL)
1563 return;
1564 VERBOSE_PRINTK_STRING("Stopping rcu_torture_onoff task");
1565 kthread_stop(onoff_task);
1566 onoff_task = NULL;
1567 }
1568
1569 #else /* #ifdef CONFIG_HOTPLUG_CPU */
1570
1571 static int
1572 rcu_torture_onoff_init(void)
1573 {
1574 return 0;
1575 }
1576
1577 static void rcu_torture_onoff_cleanup(void)
1578 {
1579 }
1580
1581 #endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
1582
1583 /*
1584 * CPU-stall kthread. It waits as specified by stall_cpu_holdoff, then
1585 * induces a CPU stall for the time specified by stall_cpu.
1586 */
1587 static int __cpuinit rcu_torture_stall(void *args)
1588 {
1589 unsigned long stop_at;
1590
1591 VERBOSE_PRINTK_STRING("rcu_torture_stall task started");
1592 if (stall_cpu_holdoff > 0) {
1593 VERBOSE_PRINTK_STRING("rcu_torture_stall begin holdoff");
1594 schedule_timeout_interruptible(stall_cpu_holdoff * HZ);
1595 VERBOSE_PRINTK_STRING("rcu_torture_stall end holdoff");
1596 }
1597 if (!kthread_should_stop()) {
1598 stop_at = get_seconds() + stall_cpu;
1599 /* RCU CPU stall is expected behavior in following code. */
1600 printk(KERN_ALERT "rcu_torture_stall start.\n");
1601 rcu_read_lock();
1602 preempt_disable();
1603 while (ULONG_CMP_LT(get_seconds(), stop_at))
1604 continue; /* Induce RCU CPU stall warning. */
1605 preempt_enable();
1606 rcu_read_unlock();
1607 printk(KERN_ALERT "rcu_torture_stall end.\n");
1608 }
1609 rcutorture_shutdown_absorb("rcu_torture_stall");
1610 while (!kthread_should_stop())
1611 schedule_timeout_interruptible(10 * HZ);
1612 return 0;
1613 }
1614
1615 /* Spawn CPU-stall kthread, if stall_cpu specified. */
1616 static int __init rcu_torture_stall_init(void)
1617 {
1618 int ret;
1619
1620 if (stall_cpu <= 0)
1621 return 0;
1622 stall_task = kthread_run(rcu_torture_stall, NULL, "rcu_torture_stall");
1623 if (IS_ERR(stall_task)) {
1624 ret = PTR_ERR(stall_task);
1625 stall_task = NULL;
1626 return ret;
1627 }
1628 return 0;
1629 }
1630
1631 /* Clean up after the CPU-stall kthread, if one was spawned. */
1632 static void rcu_torture_stall_cleanup(void)
1633 {
1634 if (stall_task == NULL)
1635 return;
1636 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stall_task.");
1637 kthread_stop(stall_task);
1638 stall_task = NULL;
1639 }
1640
1641 /* Callback function for RCU barrier testing. */
1642 void rcu_torture_barrier_cbf(struct rcu_head *rcu)
1643 {
1644 atomic_inc(&barrier_cbs_invoked);
1645 }
1646
1647 /* kthread function to register callbacks used to test RCU barriers. */
1648 static int rcu_torture_barrier_cbs(void *arg)
1649 {
1650 long myid = (long)arg;
1651 bool lastphase = 0;
1652 struct rcu_head rcu;
1653
1654 init_rcu_head_on_stack(&rcu);
1655 VERBOSE_PRINTK_STRING("rcu_torture_barrier_cbs task started");
1656 set_user_nice(current, 19);
1657 do {
1658 wait_event(barrier_cbs_wq[myid],
1659 barrier_phase != lastphase ||
1660 kthread_should_stop() ||
1661 fullstop != FULLSTOP_DONTSTOP);
1662 lastphase = barrier_phase;
1663 smp_mb(); /* ensure barrier_phase load before ->call(). */
1664 if (kthread_should_stop() || fullstop != FULLSTOP_DONTSTOP)
1665 break;
1666 cur_ops->call(&rcu, rcu_torture_barrier_cbf);
1667 if (atomic_dec_and_test(&barrier_cbs_count))
1668 wake_up(&barrier_wq);
1669 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1670 VERBOSE_PRINTK_STRING("rcu_torture_barrier_cbs task stopping");
1671 rcutorture_shutdown_absorb("rcu_torture_barrier_cbs");
1672 while (!kthread_should_stop())
1673 schedule_timeout_interruptible(1);
1674 cur_ops->cb_barrier();
1675 destroy_rcu_head_on_stack(&rcu);
1676 return 0;
1677 }
1678
1679 /* kthread function to drive and coordinate RCU barrier testing. */
1680 static int rcu_torture_barrier(void *arg)
1681 {
1682 int i;
1683
1684 VERBOSE_PRINTK_STRING("rcu_torture_barrier task starting");
1685 do {
1686 atomic_set(&barrier_cbs_invoked, 0);
1687 atomic_set(&barrier_cbs_count, n_barrier_cbs);
1688 smp_mb(); /* Ensure barrier_phase after prior assignments. */
1689 barrier_phase = !barrier_phase;
1690 for (i = 0; i < n_barrier_cbs; i++)
1691 wake_up(&barrier_cbs_wq[i]);
1692 wait_event(barrier_wq,
1693 atomic_read(&barrier_cbs_count) == 0 ||
1694 kthread_should_stop() ||
1695 fullstop != FULLSTOP_DONTSTOP);
1696 if (kthread_should_stop() || fullstop != FULLSTOP_DONTSTOP)
1697 break;
1698 n_barrier_attempts++;
1699 cur_ops->cb_barrier();
1700 if (atomic_read(&barrier_cbs_invoked) != n_barrier_cbs) {
1701 n_rcu_torture_barrier_error++;
1702 WARN_ON_ONCE(1);
1703 }
1704 n_barrier_successes++;
1705 schedule_timeout_interruptible(HZ / 10);
1706 } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
1707 VERBOSE_PRINTK_STRING("rcu_torture_barrier task stopping");
1708 rcutorture_shutdown_absorb("rcu_torture_barrier");
1709 while (!kthread_should_stop())
1710 schedule_timeout_interruptible(1);
1711 return 0;
1712 }
1713
1714 /* Initialize RCU barrier testing. */
1715 static int rcu_torture_barrier_init(void)
1716 {
1717 int i;
1718 int ret;
1719
1720 if (n_barrier_cbs == 0)
1721 return 0;
1722 if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {
1723 printk(KERN_ALERT "%s" TORTURE_FLAG
1724 " Call or barrier ops missing for %s,\n",
1725 torture_type, cur_ops->name);
1726 printk(KERN_ALERT "%s" TORTURE_FLAG
1727 " RCU barrier testing omitted from run.\n",
1728 torture_type);
1729 return 0;
1730 }
1731 atomic_set(&barrier_cbs_count, 0);
1732 atomic_set(&barrier_cbs_invoked, 0);
1733 barrier_cbs_tasks =
1734 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_tasks[0]),
1735 GFP_KERNEL);
1736 barrier_cbs_wq =
1737 kzalloc(n_barrier_cbs * sizeof(barrier_cbs_wq[0]),
1738 GFP_KERNEL);
1739 if (barrier_cbs_tasks == NULL || barrier_cbs_wq == 0)
1740 return -ENOMEM;
1741 for (i = 0; i < n_barrier_cbs; i++) {
1742 init_waitqueue_head(&barrier_cbs_wq[i]);
1743 barrier_cbs_tasks[i] = kthread_run(rcu_torture_barrier_cbs,
1744 (void *)(long)i,
1745 "rcu_torture_barrier_cbs");
1746 if (IS_ERR(barrier_cbs_tasks[i])) {
1747 ret = PTR_ERR(barrier_cbs_tasks[i]);
1748 VERBOSE_PRINTK_ERRSTRING("Failed to create rcu_torture_barrier_cbs");
1749 barrier_cbs_tasks[i] = NULL;
1750 return ret;
1751 }
1752 }
1753 barrier_task = kthread_run(rcu_torture_barrier, NULL,
1754 "rcu_torture_barrier");
1755 if (IS_ERR(barrier_task)) {
1756 ret = PTR_ERR(barrier_task);
1757 VERBOSE_PRINTK_ERRSTRING("Failed to create rcu_torture_barrier");
1758 barrier_task = NULL;
1759 }
1760 return 0;
1761 }
1762
1763 /* Clean up after RCU barrier testing. */
1764 static void rcu_torture_barrier_cleanup(void)
1765 {
1766 int i;
1767
1768 if (barrier_task != NULL) {
1769 VERBOSE_PRINTK_STRING("Stopping rcu_torture_barrier task");
1770 kthread_stop(barrier_task);
1771 barrier_task = NULL;
1772 }
1773 if (barrier_cbs_tasks != NULL) {
1774 for (i = 0; i < n_barrier_cbs; i++) {
1775 if (barrier_cbs_tasks[i] != NULL) {
1776 VERBOSE_PRINTK_STRING("Stopping rcu_torture_barrier_cbs task");
1777 kthread_stop(barrier_cbs_tasks[i]);
1778 barrier_cbs_tasks[i] = NULL;
1779 }
1780 }
1781 kfree(barrier_cbs_tasks);
1782 barrier_cbs_tasks = NULL;
1783 }
1784 if (barrier_cbs_wq != NULL) {
1785 kfree(barrier_cbs_wq);
1786 barrier_cbs_wq = NULL;
1787 }
1788 }
1789
1790 static int rcutorture_cpu_notify(struct notifier_block *self,
1791 unsigned long action, void *hcpu)
1792 {
1793 long cpu = (long)hcpu;
1794
1795 switch (action) {
1796 case CPU_ONLINE:
1797 case CPU_DOWN_FAILED:
1798 (void)rcutorture_booster_init(cpu);
1799 break;
1800 case CPU_DOWN_PREPARE:
1801 rcutorture_booster_cleanup(cpu);
1802 break;
1803 default:
1804 break;
1805 }
1806 return NOTIFY_OK;
1807 }
1808
1809 static struct notifier_block rcutorture_cpu_nb = {
1810 .notifier_call = rcutorture_cpu_notify,
1811 };
1812
1813 static void
1814 rcu_torture_cleanup(void)
1815 {
1816 int i;
1817
1818 mutex_lock(&fullstop_mutex);
1819 rcutorture_record_test_transition();
1820 if (fullstop == FULLSTOP_SHUTDOWN) {
1821 printk(KERN_WARNING /* but going down anyway, so... */
1822 "Concurrent 'rmmod rcutorture' and shutdown illegal!\n");
1823 mutex_unlock(&fullstop_mutex);
1824 schedule_timeout_uninterruptible(10);
1825 if (cur_ops->cb_barrier != NULL)
1826 cur_ops->cb_barrier();
1827 return;
1828 }
1829 fullstop = FULLSTOP_RMMOD;
1830 mutex_unlock(&fullstop_mutex);
1831 unregister_reboot_notifier(&rcutorture_shutdown_nb);
1832 rcu_torture_barrier_cleanup();
1833 rcu_torture_stall_cleanup();
1834 if (stutter_task) {
1835 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
1836 kthread_stop(stutter_task);
1837 }
1838 stutter_task = NULL;
1839 if (shuffler_task) {
1840 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
1841 kthread_stop(shuffler_task);
1842 free_cpumask_var(shuffle_tmp_mask);
1843 }
1844 shuffler_task = NULL;
1845
1846 if (writer_task) {
1847 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
1848 kthread_stop(writer_task);
1849 }
1850 writer_task = NULL;
1851
1852 if (reader_tasks) {
1853 for (i = 0; i < nrealreaders; i++) {
1854 if (reader_tasks[i]) {
1855 VERBOSE_PRINTK_STRING(
1856 "Stopping rcu_torture_reader task");
1857 kthread_stop(reader_tasks[i]);
1858 }
1859 reader_tasks[i] = NULL;
1860 }
1861 kfree(reader_tasks);
1862 reader_tasks = NULL;
1863 }
1864 rcu_torture_current = NULL;
1865
1866 if (fakewriter_tasks) {
1867 for (i = 0; i < nfakewriters; i++) {
1868 if (fakewriter_tasks[i]) {
1869 VERBOSE_PRINTK_STRING(
1870 "Stopping rcu_torture_fakewriter task");
1871 kthread_stop(fakewriter_tasks[i]);
1872 }
1873 fakewriter_tasks[i] = NULL;
1874 }
1875 kfree(fakewriter_tasks);
1876 fakewriter_tasks = NULL;
1877 }
1878
1879 if (stats_task) {
1880 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
1881 kthread_stop(stats_task);
1882 }
1883 stats_task = NULL;
1884
1885 if (fqs_task) {
1886 VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task");
1887 kthread_stop(fqs_task);
1888 }
1889 fqs_task = NULL;
1890 if ((test_boost == 1 && cur_ops->can_boost) ||
1891 test_boost == 2) {
1892 unregister_cpu_notifier(&rcutorture_cpu_nb);
1893 for_each_possible_cpu(i)
1894 rcutorture_booster_cleanup(i);
1895 }
1896 if (shutdown_task != NULL) {
1897 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shutdown task");
1898 kthread_stop(shutdown_task);
1899 }
1900 shutdown_task = NULL;
1901 rcu_torture_onoff_cleanup();
1902
1903 /* Wait for all RCU callbacks to fire. */
1904
1905 if (cur_ops->cb_barrier != NULL)
1906 cur_ops->cb_barrier();
1907
1908 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
1909
1910 if (cur_ops->cleanup)
1911 cur_ops->cleanup();
1912 if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
1913 rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
1914 else if (n_online_successes != n_online_attempts ||
1915 n_offline_successes != n_offline_attempts)
1916 rcu_torture_print_module_parms(cur_ops,
1917 "End of test: RCU_HOTPLUG");
1918 else
1919 rcu_torture_print_module_parms(cur_ops, "End of test: SUCCESS");
1920 }
1921
1922 static int __init
1923 rcu_torture_init(void)
1924 {
1925 int i;
1926 int cpu;
1927 int firsterr = 0;
1928 int retval;
1929 static struct rcu_torture_ops *torture_ops[] =
1930 { &rcu_ops, &rcu_sync_ops, &rcu_expedited_ops,
1931 &rcu_bh_ops, &rcu_bh_sync_ops, &rcu_bh_expedited_ops,
1932 &srcu_ops, &srcu_sync_ops, &srcu_expedited_ops,
1933 &srcu_raw_ops, &srcu_raw_sync_ops,
1934 &sched_ops, &sched_sync_ops, &sched_expedited_ops, };
1935
1936 mutex_lock(&fullstop_mutex);
1937
1938 /* Process args and tell the world that the torturer is on the job. */
1939 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
1940 cur_ops = torture_ops[i];
1941 if (strcmp(torture_type, cur_ops->name) == 0)
1942 break;
1943 }
1944 if (i == ARRAY_SIZE(torture_ops)) {
1945 printk(KERN_ALERT "rcu-torture: invalid torture type: \"%s\"\n",
1946 torture_type);
1947 printk(KERN_ALERT "rcu-torture types:");
1948 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
1949 printk(KERN_ALERT " %s", torture_ops[i]->name);
1950 printk(KERN_ALERT "\n");
1951 mutex_unlock(&fullstop_mutex);
1952 return -EINVAL;
1953 }
1954 if (cur_ops->fqs == NULL && fqs_duration != 0) {
1955 printk(KERN_ALERT "rcu-torture: ->fqs NULL and non-zero "
1956 "fqs_duration, fqs disabled.\n");
1957 fqs_duration = 0;
1958 }
1959 if (cur_ops->init)
1960 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
1961
1962 if (nreaders >= 0)
1963 nrealreaders = nreaders;
1964 else
1965 nrealreaders = 2 * num_online_cpus();
1966 rcu_torture_print_module_parms(cur_ops, "Start of test");
1967 fullstop = FULLSTOP_DONTSTOP;
1968
1969 /* Set up the freelist. */
1970
1971 INIT_LIST_HEAD(&rcu_torture_freelist);
1972 for (i = 0; i < ARRAY_SIZE(rcu_tortures); i++) {
1973 rcu_tortures[i].rtort_mbtest = 0;
1974 list_add_tail(&rcu_tortures[i].rtort_free,
1975 &rcu_torture_freelist);
1976 }
1977
1978 /* Initialize the statistics so that each run gets its own numbers. */
1979
1980 rcu_torture_current = NULL;
1981 rcu_torture_current_version = 0;
1982 atomic_set(&n_rcu_torture_alloc, 0);
1983 atomic_set(&n_rcu_torture_alloc_fail, 0);
1984 atomic_set(&n_rcu_torture_free, 0);
1985 atomic_set(&n_rcu_torture_mberror, 0);
1986 atomic_set(&n_rcu_torture_error, 0);
1987 n_rcu_torture_barrier_error = 0;
1988 n_rcu_torture_boost_ktrerror = 0;
1989 n_rcu_torture_boost_rterror = 0;
1990 n_rcu_torture_boost_failure = 0;
1991 n_rcu_torture_boosts = 0;
1992 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
1993 atomic_set(&rcu_torture_wcount[i], 0);
1994 for_each_possible_cpu(cpu) {
1995 for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
1996 per_cpu(rcu_torture_count, cpu)[i] = 0;
1997 per_cpu(rcu_torture_batch, cpu)[i] = 0;
1998 }
1999 }
2000
2001 /* Start up the kthreads. */
2002
2003 VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
2004 writer_task = kthread_run(rcu_torture_writer, NULL,
2005 "rcu_torture_writer");
2006 if (IS_ERR(writer_task)) {
2007 firsterr = PTR_ERR(writer_task);
2008 VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
2009 writer_task = NULL;
2010 goto unwind;
2011 }
2012 fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),
2013 GFP_KERNEL);
2014 if (fakewriter_tasks == NULL) {
2015 VERBOSE_PRINTK_ERRSTRING("out of memory");
2016 firsterr = -ENOMEM;
2017 goto unwind;
2018 }
2019 for (i = 0; i < nfakewriters; i++) {
2020 VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task");
2021 fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL,
2022 "rcu_torture_fakewriter");
2023 if (IS_ERR(fakewriter_tasks[i])) {
2024 firsterr = PTR_ERR(fakewriter_tasks[i]);
2025 VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter");
2026 fakewriter_tasks[i] = NULL;
2027 goto unwind;
2028 }
2029 }
2030 reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]),
2031 GFP_KERNEL);
2032 if (reader_tasks == NULL) {
2033 VERBOSE_PRINTK_ERRSTRING("out of memory");
2034 firsterr = -ENOMEM;
2035 goto unwind;
2036 }
2037 for (i = 0; i < nrealreaders; i++) {
2038 VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
2039 reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
2040 "rcu_torture_reader");
2041 if (IS_ERR(reader_tasks[i])) {
2042 firsterr = PTR_ERR(reader_tasks[i]);
2043 VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
2044 reader_tasks[i] = NULL;
2045 goto unwind;
2046 }
2047 }
2048 if (stat_interval > 0) {
2049 VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
2050 stats_task = kthread_run(rcu_torture_stats, NULL,
2051 "rcu_torture_stats");
2052 if (IS_ERR(stats_task)) {
2053 firsterr = PTR_ERR(stats_task);
2054 VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
2055 stats_task = NULL;
2056 goto unwind;
2057 }
2058 }
2059 if (test_no_idle_hz) {
2060 rcu_idle_cpu = num_online_cpus() - 1;
2061
2062 if (!alloc_cpumask_var(&shuffle_tmp_mask, GFP_KERNEL)) {
2063 firsterr = -ENOMEM;
2064 VERBOSE_PRINTK_ERRSTRING("Failed to alloc mask");
2065 goto unwind;
2066 }
2067
2068 /* Create the shuffler thread */
2069 shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
2070 "rcu_torture_shuffle");
2071 if (IS_ERR(shuffler_task)) {
2072 free_cpumask_var(shuffle_tmp_mask);
2073 firsterr = PTR_ERR(shuffler_task);
2074 VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
2075 shuffler_task = NULL;
2076 goto unwind;
2077 }
2078 }
2079 if (stutter < 0)
2080 stutter = 0;
2081 if (stutter) {
2082 /* Create the stutter thread */
2083 stutter_task = kthread_run(rcu_torture_stutter, NULL,
2084 "rcu_torture_stutter");
2085 if (IS_ERR(stutter_task)) {
2086 firsterr = PTR_ERR(stutter_task);
2087 VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
2088 stutter_task = NULL;
2089 goto unwind;
2090 }
2091 }
2092 if (fqs_duration < 0)
2093 fqs_duration = 0;
2094 if (fqs_duration) {
2095 /* Create the stutter thread */
2096 fqs_task = kthread_run(rcu_torture_fqs, NULL,
2097 "rcu_torture_fqs");
2098 if (IS_ERR(fqs_task)) {
2099 firsterr = PTR_ERR(fqs_task);
2100 VERBOSE_PRINTK_ERRSTRING("Failed to create fqs");
2101 fqs_task = NULL;
2102 goto unwind;
2103 }
2104 }
2105 if (test_boost_interval < 1)
2106 test_boost_interval = 1;
2107 if (test_boost_duration < 2)
2108 test_boost_duration = 2;
2109 if ((test_boost == 1 && cur_ops->can_boost) ||
2110 test_boost == 2) {
2111
2112 boost_starttime = jiffies + test_boost_interval * HZ;
2113 register_cpu_notifier(&rcutorture_cpu_nb);
2114 for_each_possible_cpu(i) {
2115 if (cpu_is_offline(i))
2116 continue; /* Heuristic: CPU can go offline. */
2117 retval = rcutorture_booster_init(i);
2118 if (retval < 0) {
2119 firsterr = retval;
2120 goto unwind;
2121 }
2122 }
2123 }
2124 if (shutdown_secs > 0) {
2125 shutdown_time = jiffies + shutdown_secs * HZ;
2126 shutdown_task = kthread_run(rcu_torture_shutdown, NULL,
2127 "rcu_torture_shutdown");
2128 if (IS_ERR(shutdown_task)) {
2129 firsterr = PTR_ERR(shutdown_task);
2130 VERBOSE_PRINTK_ERRSTRING("Failed to create shutdown");
2131 shutdown_task = NULL;
2132 goto unwind;
2133 }
2134 }
2135 i = rcu_torture_onoff_init();
2136 if (i != 0) {
2137 firsterr = i;
2138 goto unwind;
2139 }
2140 register_reboot_notifier(&rcutorture_shutdown_nb);
2141 i = rcu_torture_stall_init();
2142 if (i != 0) {
2143 firsterr = i;
2144 goto unwind;
2145 }
2146 retval = rcu_torture_barrier_init();
2147 if (retval != 0) {
2148 firsterr = retval;
2149 goto unwind;
2150 }
2151 rcutorture_record_test_transition();
2152 mutex_unlock(&fullstop_mutex);
2153 return 0;
2154
2155 unwind:
2156 mutex_unlock(&fullstop_mutex);
2157 rcu_torture_cleanup();
2158 return firsterr;
2159 }
2160
2161 module_init(rcu_torture_init);
2162 module_exit(rcu_torture_cleanup);
Linux kernel - Deliverables
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