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