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a241ec65 | 1 | /* |
29766f1e | 2 | * Read-Copy Update module-based torture test facility |
a241ec65 PM |
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 | * | |
b772e1dd | 18 | * Copyright (C) IBM Corporation, 2005, 2006 |
a241ec65 PM |
19 | * |
20 | * Authors: Paul E. McKenney <paulmck@us.ibm.com> | |
b772e1dd | 21 | * Josh Triplett <josh@freedesktop.org> |
a241ec65 PM |
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 <asm/atomic.h> | |
37 | #include <linux/bitops.h> | |
38 | #include <linux/module.h> | |
39 | #include <linux/completion.h> | |
40 | #include <linux/moduleparam.h> | |
41 | #include <linux/percpu.h> | |
42 | #include <linux/notifier.h> | |
a241ec65 PM |
43 | #include <linux/cpu.h> |
44 | #include <linux/random.h> | |
45 | #include <linux/delay.h> | |
46 | #include <linux/byteorder/swabb.h> | |
47 | #include <linux/stat.h> | |
b2896d2e | 48 | #include <linux/srcu.h> |
a241ec65 PM |
49 | |
50 | MODULE_LICENSE("GPL"); | |
b772e1dd JT |
51 | MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com> and " |
52 | "Josh Triplett <josh@freedesktop.org>"); | |
a241ec65 | 53 | |
4802211c | 54 | static int nreaders = -1; /* # reader threads, defaults to 2*ncpus */ |
b772e1dd | 55 | static int nfakewriters = 4; /* # fake writer threads */ |
d84f5203 | 56 | static int stat_interval; /* Interval between stats, in seconds. */ |
a241ec65 | 57 | /* Defaults to "only at end of test". */ |
d84f5203 SV |
58 | static int verbose; /* Print more debug info. */ |
59 | static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */ | |
60 | static int shuffle_interval = 5; /* Interval between shuffles (in sec)*/ | |
3c29e03d | 61 | static char *torture_type = "rcu"; /* What to torture: rcu, rcu_bh, srcu. */ |
a241ec65 | 62 | |
8d3b33f6 | 63 | module_param(nreaders, int, 0); |
a241ec65 | 64 | MODULE_PARM_DESC(nreaders, "Number of RCU reader threads"); |
b772e1dd JT |
65 | module_param(nfakewriters, int, 0); |
66 | MODULE_PARM_DESC(nfakewriters, "Number of RCU fake writer threads"); | |
8d3b33f6 | 67 | module_param(stat_interval, int, 0); |
a241ec65 | 68 | MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s"); |
8d3b33f6 | 69 | module_param(verbose, bool, 0); |
a241ec65 | 70 | MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s"); |
8d3b33f6 | 71 | module_param(test_no_idle_hz, bool, 0); |
d84f5203 | 72 | MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs"); |
8d3b33f6 | 73 | module_param(shuffle_interval, int, 0); |
d84f5203 | 74 | MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles"); |
72e9bb54 | 75 | module_param(torture_type, charp, 0); |
b2896d2e | 76 | MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)"); |
72e9bb54 PM |
77 | |
78 | #define TORTURE_FLAG "-torture:" | |
a241ec65 | 79 | #define PRINTK_STRING(s) \ |
72e9bb54 | 80 | do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0) |
a241ec65 | 81 | #define VERBOSE_PRINTK_STRING(s) \ |
72e9bb54 | 82 | do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0) |
a241ec65 | 83 | #define VERBOSE_PRINTK_ERRSTRING(s) \ |
72e9bb54 | 84 | do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0) |
a241ec65 PM |
85 | |
86 | static char printk_buf[4096]; | |
87 | ||
88 | static int nrealreaders; | |
89 | static struct task_struct *writer_task; | |
b772e1dd | 90 | static struct task_struct **fakewriter_tasks; |
a241ec65 PM |
91 | static struct task_struct **reader_tasks; |
92 | static struct task_struct *stats_task; | |
d84f5203 | 93 | static struct task_struct *shuffler_task; |
a241ec65 PM |
94 | |
95 | #define RCU_TORTURE_PIPE_LEN 10 | |
96 | ||
97 | struct rcu_torture { | |
98 | struct rcu_head rtort_rcu; | |
99 | int rtort_pipe_count; | |
100 | struct list_head rtort_free; | |
996417d2 | 101 | int rtort_mbtest; |
a241ec65 PM |
102 | }; |
103 | ||
104 | static int fullstop = 0; /* stop generating callbacks at test end. */ | |
105 | static LIST_HEAD(rcu_torture_freelist); | |
106 | static struct rcu_torture *rcu_torture_current = NULL; | |
107 | static long rcu_torture_current_version = 0; | |
108 | static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; | |
109 | static DEFINE_SPINLOCK(rcu_torture_lock); | |
110 | static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) = | |
111 | { 0 }; | |
112 | static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) = | |
113 | { 0 }; | |
114 | static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; | |
b2896d2e PM |
115 | static atomic_t n_rcu_torture_alloc; |
116 | static atomic_t n_rcu_torture_alloc_fail; | |
117 | static atomic_t n_rcu_torture_free; | |
118 | static atomic_t n_rcu_torture_mberror; | |
119 | static atomic_t n_rcu_torture_error; | |
e3033736 | 120 | static struct list_head rcu_torture_removed; |
a241ec65 PM |
121 | |
122 | /* | |
123 | * Allocate an element from the rcu_tortures pool. | |
124 | */ | |
97a41e26 | 125 | static struct rcu_torture * |
a241ec65 PM |
126 | rcu_torture_alloc(void) |
127 | { | |
128 | struct list_head *p; | |
129 | ||
adac1665 | 130 | spin_lock_bh(&rcu_torture_lock); |
a241ec65 PM |
131 | if (list_empty(&rcu_torture_freelist)) { |
132 | atomic_inc(&n_rcu_torture_alloc_fail); | |
adac1665 | 133 | spin_unlock_bh(&rcu_torture_lock); |
a241ec65 PM |
134 | return NULL; |
135 | } | |
136 | atomic_inc(&n_rcu_torture_alloc); | |
137 | p = rcu_torture_freelist.next; | |
138 | list_del_init(p); | |
adac1665 | 139 | spin_unlock_bh(&rcu_torture_lock); |
a241ec65 PM |
140 | return container_of(p, struct rcu_torture, rtort_free); |
141 | } | |
142 | ||
143 | /* | |
144 | * Free an element to the rcu_tortures pool. | |
145 | */ | |
146 | static void | |
147 | rcu_torture_free(struct rcu_torture *p) | |
148 | { | |
149 | atomic_inc(&n_rcu_torture_free); | |
adac1665 | 150 | spin_lock_bh(&rcu_torture_lock); |
a241ec65 | 151 | list_add_tail(&p->rtort_free, &rcu_torture_freelist); |
adac1665 | 152 | spin_unlock_bh(&rcu_torture_lock); |
a241ec65 PM |
153 | } |
154 | ||
a241ec65 PM |
155 | struct rcu_random_state { |
156 | unsigned long rrs_state; | |
75cfef32 | 157 | long rrs_count; |
a241ec65 PM |
158 | }; |
159 | ||
160 | #define RCU_RANDOM_MULT 39916801 /* prime */ | |
161 | #define RCU_RANDOM_ADD 479001701 /* prime */ | |
162 | #define RCU_RANDOM_REFRESH 10000 | |
163 | ||
164 | #define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 } | |
165 | ||
166 | /* | |
167 | * Crude but fast random-number generator. Uses a linear congruential | |
168 | * generator, with occasional help from get_random_bytes(). | |
169 | */ | |
75cfef32 | 170 | static unsigned long |
a241ec65 PM |
171 | rcu_random(struct rcu_random_state *rrsp) |
172 | { | |
173 | long refresh; | |
174 | ||
175 | if (--rrsp->rrs_count < 0) { | |
176 | get_random_bytes(&refresh, sizeof(refresh)); | |
177 | rrsp->rrs_state += refresh; | |
178 | rrsp->rrs_count = RCU_RANDOM_REFRESH; | |
179 | } | |
180 | rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD; | |
181 | return swahw32(rrsp->rrs_state); | |
182 | } | |
183 | ||
72e9bb54 PM |
184 | /* |
185 | * Operations vector for selecting different types of tests. | |
186 | */ | |
187 | ||
188 | struct rcu_torture_ops { | |
189 | void (*init)(void); | |
190 | void (*cleanup)(void); | |
191 | int (*readlock)(void); | |
b2896d2e | 192 | void (*readdelay)(struct rcu_random_state *rrsp); |
72e9bb54 PM |
193 | void (*readunlock)(int idx); |
194 | int (*completed)(void); | |
195 | void (*deferredfree)(struct rcu_torture *p); | |
b772e1dd | 196 | void (*sync)(void); |
72e9bb54 PM |
197 | int (*stats)(char *page); |
198 | char *name; | |
199 | }; | |
200 | static struct rcu_torture_ops *cur_ops = NULL; | |
201 | ||
202 | /* | |
203 | * Definitions for rcu torture testing. | |
204 | */ | |
205 | ||
a49a4af7 | 206 | static int rcu_torture_read_lock(void) __acquires(RCU) |
72e9bb54 PM |
207 | { |
208 | rcu_read_lock(); | |
209 | return 0; | |
210 | } | |
211 | ||
b2896d2e PM |
212 | static void rcu_read_delay(struct rcu_random_state *rrsp) |
213 | { | |
214 | long delay; | |
215 | const long longdelay = 200; | |
216 | ||
217 | /* We want there to be long-running readers, but not all the time. */ | |
218 | ||
219 | delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay); | |
220 | if (!delay) | |
221 | udelay(longdelay); | |
222 | } | |
223 | ||
a49a4af7 | 224 | static void rcu_torture_read_unlock(int idx) __releases(RCU) |
72e9bb54 PM |
225 | { |
226 | rcu_read_unlock(); | |
227 | } | |
228 | ||
229 | static int rcu_torture_completed(void) | |
230 | { | |
231 | return rcu_batches_completed(); | |
232 | } | |
233 | ||
234 | static void | |
235 | rcu_torture_cb(struct rcu_head *p) | |
236 | { | |
237 | int i; | |
238 | struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); | |
239 | ||
240 | if (fullstop) { | |
241 | /* Test is ending, just drop callbacks on the floor. */ | |
242 | /* The next initialization will pick up the pieces. */ | |
243 | return; | |
244 | } | |
245 | i = rp->rtort_pipe_count; | |
246 | if (i > RCU_TORTURE_PIPE_LEN) | |
247 | i = RCU_TORTURE_PIPE_LEN; | |
248 | atomic_inc(&rcu_torture_wcount[i]); | |
249 | if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { | |
250 | rp->rtort_mbtest = 0; | |
251 | rcu_torture_free(rp); | |
252 | } else | |
253 | cur_ops->deferredfree(rp); | |
254 | } | |
255 | ||
256 | static void rcu_torture_deferred_free(struct rcu_torture *p) | |
257 | { | |
258 | call_rcu(&p->rtort_rcu, rcu_torture_cb); | |
259 | } | |
260 | ||
261 | static struct rcu_torture_ops rcu_ops = { | |
262 | .init = NULL, | |
263 | .cleanup = NULL, | |
264 | .readlock = rcu_torture_read_lock, | |
b2896d2e | 265 | .readdelay = rcu_read_delay, |
72e9bb54 PM |
266 | .readunlock = rcu_torture_read_unlock, |
267 | .completed = rcu_torture_completed, | |
268 | .deferredfree = rcu_torture_deferred_free, | |
b772e1dd | 269 | .sync = synchronize_rcu, |
72e9bb54 PM |
270 | .stats = NULL, |
271 | .name = "rcu" | |
272 | }; | |
273 | ||
e3033736 JT |
274 | static void rcu_sync_torture_deferred_free(struct rcu_torture *p) |
275 | { | |
276 | int i; | |
277 | struct rcu_torture *rp; | |
278 | struct rcu_torture *rp1; | |
279 | ||
280 | cur_ops->sync(); | |
281 | list_add(&p->rtort_free, &rcu_torture_removed); | |
282 | list_for_each_entry_safe(rp, rp1, &rcu_torture_removed, rtort_free) { | |
283 | i = rp->rtort_pipe_count; | |
284 | if (i > RCU_TORTURE_PIPE_LEN) | |
285 | i = RCU_TORTURE_PIPE_LEN; | |
286 | atomic_inc(&rcu_torture_wcount[i]); | |
287 | if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { | |
288 | rp->rtort_mbtest = 0; | |
289 | list_del(&rp->rtort_free); | |
290 | rcu_torture_free(rp); | |
291 | } | |
292 | } | |
293 | } | |
294 | ||
295 | static void rcu_sync_torture_init(void) | |
296 | { | |
297 | INIT_LIST_HEAD(&rcu_torture_removed); | |
298 | } | |
299 | ||
c32e0660 PM |
300 | /* |
301 | * Definitions for rcu_bh torture testing. | |
302 | */ | |
303 | ||
a49a4af7 | 304 | static int rcu_bh_torture_read_lock(void) __acquires(RCU_BH) |
c32e0660 PM |
305 | { |
306 | rcu_read_lock_bh(); | |
307 | return 0; | |
308 | } | |
309 | ||
a49a4af7 | 310 | static void rcu_bh_torture_read_unlock(int idx) __releases(RCU_BH) |
c32e0660 PM |
311 | { |
312 | rcu_read_unlock_bh(); | |
313 | } | |
314 | ||
315 | static int rcu_bh_torture_completed(void) | |
316 | { | |
317 | return rcu_batches_completed_bh(); | |
318 | } | |
319 | ||
320 | static void rcu_bh_torture_deferred_free(struct rcu_torture *p) | |
321 | { | |
322 | call_rcu_bh(&p->rtort_rcu, rcu_torture_cb); | |
323 | } | |
324 | ||
b772e1dd JT |
325 | struct rcu_bh_torture_synchronize { |
326 | struct rcu_head head; | |
327 | struct completion completion; | |
328 | }; | |
329 | ||
330 | static void rcu_bh_torture_wakeme_after_cb(struct rcu_head *head) | |
331 | { | |
332 | struct rcu_bh_torture_synchronize *rcu; | |
333 | ||
334 | rcu = container_of(head, struct rcu_bh_torture_synchronize, head); | |
335 | complete(&rcu->completion); | |
336 | } | |
337 | ||
338 | static void rcu_bh_torture_synchronize(void) | |
339 | { | |
340 | struct rcu_bh_torture_synchronize rcu; | |
341 | ||
342 | init_completion(&rcu.completion); | |
343 | call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb); | |
344 | wait_for_completion(&rcu.completion); | |
345 | } | |
346 | ||
c32e0660 PM |
347 | static struct rcu_torture_ops rcu_bh_ops = { |
348 | .init = NULL, | |
349 | .cleanup = NULL, | |
350 | .readlock = rcu_bh_torture_read_lock, | |
b2896d2e | 351 | .readdelay = rcu_read_delay, /* just reuse rcu's version. */ |
c32e0660 PM |
352 | .readunlock = rcu_bh_torture_read_unlock, |
353 | .completed = rcu_bh_torture_completed, | |
354 | .deferredfree = rcu_bh_torture_deferred_free, | |
b772e1dd | 355 | .sync = rcu_bh_torture_synchronize, |
c32e0660 PM |
356 | .stats = NULL, |
357 | .name = "rcu_bh" | |
358 | }; | |
359 | ||
b2896d2e PM |
360 | /* |
361 | * Definitions for srcu torture testing. | |
362 | */ | |
363 | ||
364 | static struct srcu_struct srcu_ctl; | |
b2896d2e PM |
365 | |
366 | static void srcu_torture_init(void) | |
367 | { | |
368 | init_srcu_struct(&srcu_ctl); | |
e3033736 | 369 | rcu_sync_torture_init(); |
b2896d2e PM |
370 | } |
371 | ||
372 | static void srcu_torture_cleanup(void) | |
373 | { | |
374 | synchronize_srcu(&srcu_ctl); | |
375 | cleanup_srcu_struct(&srcu_ctl); | |
376 | } | |
377 | ||
378 | static int srcu_torture_read_lock(void) | |
379 | { | |
380 | return srcu_read_lock(&srcu_ctl); | |
381 | } | |
382 | ||
383 | static void srcu_read_delay(struct rcu_random_state *rrsp) | |
384 | { | |
385 | long delay; | |
386 | const long uspertick = 1000000 / HZ; | |
387 | const long longdelay = 10; | |
388 | ||
389 | /* We want there to be long-running readers, but not all the time. */ | |
390 | ||
391 | delay = rcu_random(rrsp) % (nrealreaders * 2 * longdelay * uspertick); | |
392 | if (!delay) | |
393 | schedule_timeout_interruptible(longdelay); | |
394 | } | |
395 | ||
396 | static void srcu_torture_read_unlock(int idx) | |
397 | { | |
398 | srcu_read_unlock(&srcu_ctl, idx); | |
399 | } | |
400 | ||
401 | static int srcu_torture_completed(void) | |
402 | { | |
403 | return srcu_batches_completed(&srcu_ctl); | |
404 | } | |
405 | ||
b772e1dd JT |
406 | static void srcu_torture_synchronize(void) |
407 | { | |
408 | synchronize_srcu(&srcu_ctl); | |
409 | } | |
410 | ||
b2896d2e PM |
411 | static int srcu_torture_stats(char *page) |
412 | { | |
413 | int cnt = 0; | |
414 | int cpu; | |
415 | int idx = srcu_ctl.completed & 0x1; | |
416 | ||
417 | cnt += sprintf(&page[cnt], "%s%s per-CPU(idx=%d):", | |
418 | torture_type, TORTURE_FLAG, idx); | |
419 | for_each_possible_cpu(cpu) { | |
420 | cnt += sprintf(&page[cnt], " %d(%d,%d)", cpu, | |
421 | per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx], | |
422 | per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx]); | |
423 | } | |
424 | cnt += sprintf(&page[cnt], "\n"); | |
425 | return cnt; | |
426 | } | |
427 | ||
428 | static struct rcu_torture_ops srcu_ops = { | |
429 | .init = srcu_torture_init, | |
430 | .cleanup = srcu_torture_cleanup, | |
431 | .readlock = srcu_torture_read_lock, | |
432 | .readdelay = srcu_read_delay, | |
433 | .readunlock = srcu_torture_read_unlock, | |
434 | .completed = srcu_torture_completed, | |
e3033736 | 435 | .deferredfree = rcu_sync_torture_deferred_free, |
b772e1dd | 436 | .sync = srcu_torture_synchronize, |
b2896d2e PM |
437 | .stats = srcu_torture_stats, |
438 | .name = "srcu" | |
439 | }; | |
440 | ||
72e9bb54 | 441 | static struct rcu_torture_ops *torture_ops[] = |
b2896d2e | 442 | { &rcu_ops, &rcu_bh_ops, &srcu_ops, NULL }; |
72e9bb54 | 443 | |
a241ec65 PM |
444 | /* |
445 | * RCU torture writer kthread. Repeatedly substitutes a new structure | |
446 | * for that pointed to by rcu_torture_current, freeing the old structure | |
447 | * after a series of grace periods (the "pipeline"). | |
448 | */ | |
449 | static int | |
450 | rcu_torture_writer(void *arg) | |
451 | { | |
452 | int i; | |
453 | long oldbatch = rcu_batches_completed(); | |
454 | struct rcu_torture *rp; | |
455 | struct rcu_torture *old_rp; | |
456 | static DEFINE_RCU_RANDOM(rand); | |
457 | ||
458 | VERBOSE_PRINTK_STRING("rcu_torture_writer task started"); | |
dbdf65b1 IM |
459 | set_user_nice(current, 19); |
460 | ||
a241ec65 PM |
461 | do { |
462 | schedule_timeout_uninterruptible(1); | |
a241ec65 PM |
463 | if ((rp = rcu_torture_alloc()) == NULL) |
464 | continue; | |
465 | rp->rtort_pipe_count = 0; | |
466 | udelay(rcu_random(&rand) & 0x3ff); | |
467 | old_rp = rcu_torture_current; | |
996417d2 | 468 | rp->rtort_mbtest = 1; |
a241ec65 PM |
469 | rcu_assign_pointer(rcu_torture_current, rp); |
470 | smp_wmb(); | |
471 | if (old_rp != NULL) { | |
472 | i = old_rp->rtort_pipe_count; | |
473 | if (i > RCU_TORTURE_PIPE_LEN) | |
474 | i = RCU_TORTURE_PIPE_LEN; | |
475 | atomic_inc(&rcu_torture_wcount[i]); | |
476 | old_rp->rtort_pipe_count++; | |
72e9bb54 | 477 | cur_ops->deferredfree(old_rp); |
a241ec65 PM |
478 | } |
479 | rcu_torture_current_version++; | |
72e9bb54 | 480 | oldbatch = cur_ops->completed(); |
a241ec65 PM |
481 | } while (!kthread_should_stop() && !fullstop); |
482 | VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping"); | |
483 | while (!kthread_should_stop()) | |
484 | schedule_timeout_uninterruptible(1); | |
485 | return 0; | |
486 | } | |
487 | ||
b772e1dd JT |
488 | /* |
489 | * RCU torture fake writer kthread. Repeatedly calls sync, with a random | |
490 | * delay between calls. | |
491 | */ | |
492 | static int | |
493 | rcu_torture_fakewriter(void *arg) | |
494 | { | |
495 | DEFINE_RCU_RANDOM(rand); | |
496 | ||
497 | VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task started"); | |
498 | set_user_nice(current, 19); | |
499 | ||
500 | do { | |
501 | schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10); | |
502 | udelay(rcu_random(&rand) & 0x3ff); | |
503 | cur_ops->sync(); | |
504 | } while (!kthread_should_stop() && !fullstop); | |
505 | ||
506 | VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping"); | |
507 | while (!kthread_should_stop()) | |
508 | schedule_timeout_uninterruptible(1); | |
509 | return 0; | |
510 | } | |
511 | ||
a241ec65 PM |
512 | /* |
513 | * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, | |
514 | * incrementing the corresponding element of the pipeline array. The | |
515 | * counter in the element should never be greater than 1, otherwise, the | |
516 | * RCU implementation is broken. | |
517 | */ | |
518 | static int | |
519 | rcu_torture_reader(void *arg) | |
520 | { | |
521 | int completed; | |
72e9bb54 | 522 | int idx; |
a241ec65 PM |
523 | DEFINE_RCU_RANDOM(rand); |
524 | struct rcu_torture *p; | |
525 | int pipe_count; | |
526 | ||
527 | VERBOSE_PRINTK_STRING("rcu_torture_reader task started"); | |
dbdf65b1 IM |
528 | set_user_nice(current, 19); |
529 | ||
a241ec65 | 530 | do { |
72e9bb54 PM |
531 | idx = cur_ops->readlock(); |
532 | completed = cur_ops->completed(); | |
a241ec65 PM |
533 | p = rcu_dereference(rcu_torture_current); |
534 | if (p == NULL) { | |
535 | /* Wait for rcu_torture_writer to get underway */ | |
72e9bb54 | 536 | cur_ops->readunlock(idx); |
a241ec65 PM |
537 | schedule_timeout_interruptible(HZ); |
538 | continue; | |
539 | } | |
996417d2 PM |
540 | if (p->rtort_mbtest == 0) |
541 | atomic_inc(&n_rcu_torture_mberror); | |
b2896d2e | 542 | cur_ops->readdelay(&rand); |
a241ec65 PM |
543 | preempt_disable(); |
544 | pipe_count = p->rtort_pipe_count; | |
545 | if (pipe_count > RCU_TORTURE_PIPE_LEN) { | |
546 | /* Should not happen, but... */ | |
547 | pipe_count = RCU_TORTURE_PIPE_LEN; | |
548 | } | |
549 | ++__get_cpu_var(rcu_torture_count)[pipe_count]; | |
72e9bb54 | 550 | completed = cur_ops->completed() - completed; |
a241ec65 PM |
551 | if (completed > RCU_TORTURE_PIPE_LEN) { |
552 | /* Should not happen, but... */ | |
553 | completed = RCU_TORTURE_PIPE_LEN; | |
554 | } | |
555 | ++__get_cpu_var(rcu_torture_batch)[completed]; | |
556 | preempt_enable(); | |
72e9bb54 | 557 | cur_ops->readunlock(idx); |
a241ec65 PM |
558 | schedule(); |
559 | } while (!kthread_should_stop() && !fullstop); | |
560 | VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping"); | |
561 | while (!kthread_should_stop()) | |
562 | schedule_timeout_uninterruptible(1); | |
563 | return 0; | |
564 | } | |
565 | ||
566 | /* | |
567 | * Create an RCU-torture statistics message in the specified buffer. | |
568 | */ | |
569 | static int | |
570 | rcu_torture_printk(char *page) | |
571 | { | |
572 | int cnt = 0; | |
573 | int cpu; | |
574 | int i; | |
575 | long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; | |
576 | long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; | |
577 | ||
0a945022 | 578 | for_each_possible_cpu(cpu) { |
a241ec65 PM |
579 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { |
580 | pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i]; | |
581 | batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i]; | |
582 | } | |
583 | } | |
584 | for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { | |
585 | if (pipesummary[i] != 0) | |
586 | break; | |
587 | } | |
72e9bb54 | 588 | cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG); |
a241ec65 | 589 | cnt += sprintf(&page[cnt], |
996417d2 PM |
590 | "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d " |
591 | "rtmbe: %d", | |
a241ec65 PM |
592 | rcu_torture_current, |
593 | rcu_torture_current_version, | |
594 | list_empty(&rcu_torture_freelist), | |
595 | atomic_read(&n_rcu_torture_alloc), | |
596 | atomic_read(&n_rcu_torture_alloc_fail), | |
996417d2 PM |
597 | atomic_read(&n_rcu_torture_free), |
598 | atomic_read(&n_rcu_torture_mberror)); | |
599 | if (atomic_read(&n_rcu_torture_mberror) != 0) | |
600 | cnt += sprintf(&page[cnt], " !!!"); | |
72e9bb54 | 601 | cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); |
996417d2 | 602 | if (i > 1) { |
a241ec65 | 603 | cnt += sprintf(&page[cnt], "!!! "); |
996417d2 PM |
604 | atomic_inc(&n_rcu_torture_error); |
605 | } | |
a241ec65 PM |
606 | cnt += sprintf(&page[cnt], "Reader Pipe: "); |
607 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) | |
608 | cnt += sprintf(&page[cnt], " %ld", pipesummary[i]); | |
72e9bb54 | 609 | cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); |
a241ec65 | 610 | cnt += sprintf(&page[cnt], "Reader Batch: "); |
72e9bb54 | 611 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) |
a241ec65 | 612 | cnt += sprintf(&page[cnt], " %ld", batchsummary[i]); |
72e9bb54 | 613 | cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); |
a241ec65 PM |
614 | cnt += sprintf(&page[cnt], "Free-Block Circulation: "); |
615 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { | |
616 | cnt += sprintf(&page[cnt], " %d", | |
617 | atomic_read(&rcu_torture_wcount[i])); | |
618 | } | |
619 | cnt += sprintf(&page[cnt], "\n"); | |
72e9bb54 PM |
620 | if (cur_ops->stats != NULL) |
621 | cnt += cur_ops->stats(&page[cnt]); | |
a241ec65 PM |
622 | return cnt; |
623 | } | |
624 | ||
625 | /* | |
626 | * Print torture statistics. Caller must ensure that there is only | |
627 | * one call to this function at a given time!!! This is normally | |
628 | * accomplished by relying on the module system to only have one copy | |
629 | * of the module loaded, and then by giving the rcu_torture_stats | |
630 | * kthread full control (or the init/cleanup functions when rcu_torture_stats | |
631 | * thread is not running). | |
632 | */ | |
633 | static void | |
634 | rcu_torture_stats_print(void) | |
635 | { | |
636 | int cnt; | |
637 | ||
638 | cnt = rcu_torture_printk(printk_buf); | |
639 | printk(KERN_ALERT "%s", printk_buf); | |
640 | } | |
641 | ||
642 | /* | |
643 | * Periodically prints torture statistics, if periodic statistics printing | |
644 | * was specified via the stat_interval module parameter. | |
645 | * | |
646 | * No need to worry about fullstop here, since this one doesn't reference | |
647 | * volatile state or register callbacks. | |
648 | */ | |
649 | static int | |
650 | rcu_torture_stats(void *arg) | |
651 | { | |
652 | VERBOSE_PRINTK_STRING("rcu_torture_stats task started"); | |
653 | do { | |
654 | schedule_timeout_interruptible(stat_interval * HZ); | |
655 | rcu_torture_stats_print(); | |
656 | } while (!kthread_should_stop()); | |
657 | VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping"); | |
658 | return 0; | |
659 | } | |
660 | ||
d84f5203 SV |
661 | static int rcu_idle_cpu; /* Force all torture tasks off this CPU */ |
662 | ||
663 | /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case | |
664 | * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs. | |
665 | */ | |
b2896d2e | 666 | static void rcu_torture_shuffle_tasks(void) |
d84f5203 SV |
667 | { |
668 | cpumask_t tmp_mask = CPU_MASK_ALL; | |
669 | int i; | |
670 | ||
671 | lock_cpu_hotplug(); | |
672 | ||
673 | /* No point in shuffling if there is only one online CPU (ex: UP) */ | |
674 | if (num_online_cpus() == 1) { | |
675 | unlock_cpu_hotplug(); | |
676 | return; | |
677 | } | |
678 | ||
679 | if (rcu_idle_cpu != -1) | |
680 | cpu_clear(rcu_idle_cpu, tmp_mask); | |
681 | ||
682 | set_cpus_allowed(current, tmp_mask); | |
683 | ||
684 | if (reader_tasks != NULL) { | |
685 | for (i = 0; i < nrealreaders; i++) | |
686 | if (reader_tasks[i]) | |
687 | set_cpus_allowed(reader_tasks[i], tmp_mask); | |
688 | } | |
689 | ||
b772e1dd JT |
690 | if (fakewriter_tasks != NULL) { |
691 | for (i = 0; i < nfakewriters; i++) | |
692 | if (fakewriter_tasks[i]) | |
693 | set_cpus_allowed(fakewriter_tasks[i], tmp_mask); | |
694 | } | |
695 | ||
d84f5203 SV |
696 | if (writer_task) |
697 | set_cpus_allowed(writer_task, tmp_mask); | |
698 | ||
699 | if (stats_task) | |
700 | set_cpus_allowed(stats_task, tmp_mask); | |
701 | ||
702 | if (rcu_idle_cpu == -1) | |
703 | rcu_idle_cpu = num_online_cpus() - 1; | |
704 | else | |
705 | rcu_idle_cpu--; | |
706 | ||
707 | unlock_cpu_hotplug(); | |
708 | } | |
709 | ||
710 | /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the | |
711 | * system to become idle at a time and cut off its timer ticks. This is meant | |
712 | * to test the support for such tickless idle CPU in RCU. | |
713 | */ | |
714 | static int | |
715 | rcu_torture_shuffle(void *arg) | |
716 | { | |
717 | VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started"); | |
718 | do { | |
719 | schedule_timeout_interruptible(shuffle_interval * HZ); | |
720 | rcu_torture_shuffle_tasks(); | |
721 | } while (!kthread_should_stop()); | |
722 | VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping"); | |
723 | return 0; | |
724 | } | |
725 | ||
95c38322 PM |
726 | static inline void |
727 | rcu_torture_print_module_parms(char *tag) | |
728 | { | |
b772e1dd JT |
729 | printk(KERN_ALERT "%s" TORTURE_FLAG |
730 | "--- %s: nreaders=%d nfakewriters=%d " | |
95c38322 PM |
731 | "stat_interval=%d verbose=%d test_no_idle_hz=%d " |
732 | "shuffle_interval = %d\n", | |
b772e1dd JT |
733 | torture_type, tag, nrealreaders, nfakewriters, |
734 | stat_interval, verbose, test_no_idle_hz, shuffle_interval); | |
95c38322 PM |
735 | } |
736 | ||
a241ec65 PM |
737 | static void |
738 | rcu_torture_cleanup(void) | |
739 | { | |
740 | int i; | |
741 | ||
742 | fullstop = 1; | |
d84f5203 SV |
743 | if (shuffler_task != NULL) { |
744 | VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task"); | |
745 | kthread_stop(shuffler_task); | |
746 | } | |
747 | shuffler_task = NULL; | |
748 | ||
a241ec65 PM |
749 | if (writer_task != NULL) { |
750 | VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task"); | |
751 | kthread_stop(writer_task); | |
752 | } | |
753 | writer_task = NULL; | |
754 | ||
755 | if (reader_tasks != NULL) { | |
756 | for (i = 0; i < nrealreaders; i++) { | |
757 | if (reader_tasks[i] != NULL) { | |
758 | VERBOSE_PRINTK_STRING( | |
759 | "Stopping rcu_torture_reader task"); | |
760 | kthread_stop(reader_tasks[i]); | |
761 | } | |
762 | reader_tasks[i] = NULL; | |
763 | } | |
764 | kfree(reader_tasks); | |
765 | reader_tasks = NULL; | |
766 | } | |
767 | rcu_torture_current = NULL; | |
768 | ||
b772e1dd JT |
769 | if (fakewriter_tasks != NULL) { |
770 | for (i = 0; i < nfakewriters; i++) { | |
771 | if (fakewriter_tasks[i] != NULL) { | |
772 | VERBOSE_PRINTK_STRING( | |
773 | "Stopping rcu_torture_fakewriter task"); | |
774 | kthread_stop(fakewriter_tasks[i]); | |
775 | } | |
776 | fakewriter_tasks[i] = NULL; | |
777 | } | |
778 | kfree(fakewriter_tasks); | |
779 | fakewriter_tasks = NULL; | |
780 | } | |
781 | ||
a241ec65 PM |
782 | if (stats_task != NULL) { |
783 | VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task"); | |
784 | kthread_stop(stats_task); | |
785 | } | |
786 | stats_task = NULL; | |
787 | ||
788 | /* Wait for all RCU callbacks to fire. */ | |
89d46b87 | 789 | rcu_barrier(); |
a241ec65 | 790 | |
a241ec65 | 791 | rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ |
72e9bb54 PM |
792 | |
793 | if (cur_ops->cleanup != NULL) | |
794 | cur_ops->cleanup(); | |
95c38322 PM |
795 | if (atomic_read(&n_rcu_torture_error)) |
796 | rcu_torture_print_module_parms("End of test: FAILURE"); | |
797 | else | |
798 | rcu_torture_print_module_parms("End of test: SUCCESS"); | |
a241ec65 PM |
799 | } |
800 | ||
801 | static int | |
802 | rcu_torture_init(void) | |
803 | { | |
804 | int i; | |
805 | int cpu; | |
806 | int firsterr = 0; | |
807 | ||
808 | /* Process args and tell the world that the torturer is on the job. */ | |
809 | ||
72e9bb54 PM |
810 | for (i = 0; cur_ops = torture_ops[i], cur_ops != NULL; i++) { |
811 | cur_ops = torture_ops[i]; | |
812 | if (strcmp(torture_type, cur_ops->name) == 0) { | |
813 | break; | |
814 | } | |
815 | } | |
816 | if (cur_ops == NULL) { | |
817 | printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n", | |
818 | torture_type); | |
819 | return (-EINVAL); | |
820 | } | |
821 | if (cur_ops->init != NULL) | |
822 | cur_ops->init(); /* no "goto unwind" prior to this point!!! */ | |
823 | ||
a241ec65 PM |
824 | if (nreaders >= 0) |
825 | nrealreaders = nreaders; | |
826 | else | |
827 | nrealreaders = 2 * num_online_cpus(); | |
95c38322 | 828 | rcu_torture_print_module_parms("Start of test"); |
a241ec65 PM |
829 | fullstop = 0; |
830 | ||
831 | /* Set up the freelist. */ | |
832 | ||
833 | INIT_LIST_HEAD(&rcu_torture_freelist); | |
834 | for (i = 0; i < sizeof(rcu_tortures) / sizeof(rcu_tortures[0]); i++) { | |
996417d2 | 835 | rcu_tortures[i].rtort_mbtest = 0; |
a241ec65 PM |
836 | list_add_tail(&rcu_tortures[i].rtort_free, |
837 | &rcu_torture_freelist); | |
838 | } | |
839 | ||
840 | /* Initialize the statistics so that each run gets its own numbers. */ | |
841 | ||
842 | rcu_torture_current = NULL; | |
843 | rcu_torture_current_version = 0; | |
844 | atomic_set(&n_rcu_torture_alloc, 0); | |
845 | atomic_set(&n_rcu_torture_alloc_fail, 0); | |
846 | atomic_set(&n_rcu_torture_free, 0); | |
996417d2 PM |
847 | atomic_set(&n_rcu_torture_mberror, 0); |
848 | atomic_set(&n_rcu_torture_error, 0); | |
a241ec65 PM |
849 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) |
850 | atomic_set(&rcu_torture_wcount[i], 0); | |
0a945022 | 851 | for_each_possible_cpu(cpu) { |
a241ec65 PM |
852 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { |
853 | per_cpu(rcu_torture_count, cpu)[i] = 0; | |
854 | per_cpu(rcu_torture_batch, cpu)[i] = 0; | |
855 | } | |
856 | } | |
857 | ||
858 | /* Start up the kthreads. */ | |
859 | ||
860 | VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task"); | |
861 | writer_task = kthread_run(rcu_torture_writer, NULL, | |
862 | "rcu_torture_writer"); | |
863 | if (IS_ERR(writer_task)) { | |
864 | firsterr = PTR_ERR(writer_task); | |
865 | VERBOSE_PRINTK_ERRSTRING("Failed to create writer"); | |
866 | writer_task = NULL; | |
867 | goto unwind; | |
868 | } | |
b772e1dd JT |
869 | fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]), |
870 | GFP_KERNEL); | |
871 | if (fakewriter_tasks == NULL) { | |
872 | VERBOSE_PRINTK_ERRSTRING("out of memory"); | |
873 | firsterr = -ENOMEM; | |
874 | goto unwind; | |
875 | } | |
876 | for (i = 0; i < nfakewriters; i++) { | |
877 | VERBOSE_PRINTK_STRING("Creating rcu_torture_fakewriter task"); | |
878 | fakewriter_tasks[i] = kthread_run(rcu_torture_fakewriter, NULL, | |
879 | "rcu_torture_fakewriter"); | |
880 | if (IS_ERR(fakewriter_tasks[i])) { | |
881 | firsterr = PTR_ERR(fakewriter_tasks[i]); | |
882 | VERBOSE_PRINTK_ERRSTRING("Failed to create fakewriter"); | |
883 | fakewriter_tasks[i] = NULL; | |
884 | goto unwind; | |
885 | } | |
886 | } | |
2860aaba | 887 | reader_tasks = kzalloc(nrealreaders * sizeof(reader_tasks[0]), |
a241ec65 PM |
888 | GFP_KERNEL); |
889 | if (reader_tasks == NULL) { | |
890 | VERBOSE_PRINTK_ERRSTRING("out of memory"); | |
891 | firsterr = -ENOMEM; | |
892 | goto unwind; | |
893 | } | |
894 | for (i = 0; i < nrealreaders; i++) { | |
895 | VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task"); | |
896 | reader_tasks[i] = kthread_run(rcu_torture_reader, NULL, | |
897 | "rcu_torture_reader"); | |
898 | if (IS_ERR(reader_tasks[i])) { | |
899 | firsterr = PTR_ERR(reader_tasks[i]); | |
900 | VERBOSE_PRINTK_ERRSTRING("Failed to create reader"); | |
901 | reader_tasks[i] = NULL; | |
902 | goto unwind; | |
903 | } | |
904 | } | |
905 | if (stat_interval > 0) { | |
906 | VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task"); | |
907 | stats_task = kthread_run(rcu_torture_stats, NULL, | |
908 | "rcu_torture_stats"); | |
909 | if (IS_ERR(stats_task)) { | |
910 | firsterr = PTR_ERR(stats_task); | |
911 | VERBOSE_PRINTK_ERRSTRING("Failed to create stats"); | |
912 | stats_task = NULL; | |
913 | goto unwind; | |
914 | } | |
915 | } | |
d84f5203 SV |
916 | if (test_no_idle_hz) { |
917 | rcu_idle_cpu = num_online_cpus() - 1; | |
918 | /* Create the shuffler thread */ | |
919 | shuffler_task = kthread_run(rcu_torture_shuffle, NULL, | |
920 | "rcu_torture_shuffle"); | |
921 | if (IS_ERR(shuffler_task)) { | |
922 | firsterr = PTR_ERR(shuffler_task); | |
923 | VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler"); | |
924 | shuffler_task = NULL; | |
925 | goto unwind; | |
926 | } | |
927 | } | |
a241ec65 PM |
928 | return 0; |
929 | ||
930 | unwind: | |
931 | rcu_torture_cleanup(); | |
932 | return firsterr; | |
933 | } | |
934 | ||
935 | module_init(rcu_torture_init); | |
936 | module_exit(rcu_torture_cleanup); |