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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 | * | |
18 | * Copyright (C) IBM Corporation, 2005 | |
19 | * | |
20 | * Authors: Paul E. McKenney <paulmck@us.ibm.com> | |
21 | * | |
22 | * See also: Documentation/RCU/torture.txt | |
23 | */ | |
24 | #include <linux/types.h> | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/module.h> | |
28 | #include <linux/kthread.h> | |
29 | #include <linux/err.h> | |
30 | #include <linux/spinlock.h> | |
31 | #include <linux/smp.h> | |
32 | #include <linux/rcupdate.h> | |
33 | #include <linux/interrupt.h> | |
34 | #include <linux/sched.h> | |
35 | #include <asm/atomic.h> | |
36 | #include <linux/bitops.h> | |
37 | #include <linux/module.h> | |
38 | #include <linux/completion.h> | |
39 | #include <linux/moduleparam.h> | |
40 | #include <linux/percpu.h> | |
41 | #include <linux/notifier.h> | |
a241ec65 PM |
42 | #include <linux/cpu.h> |
43 | #include <linux/random.h> | |
44 | #include <linux/delay.h> | |
45 | #include <linux/byteorder/swabb.h> | |
46 | #include <linux/stat.h> | |
47 | ||
48 | MODULE_LICENSE("GPL"); | |
49 | ||
50 | static int nreaders = -1; /* # reader threads, defaults to 4*ncpus */ | |
d84f5203 | 51 | static int stat_interval; /* Interval between stats, in seconds. */ |
a241ec65 | 52 | /* Defaults to "only at end of test". */ |
d84f5203 SV |
53 | static int verbose; /* Print more debug info. */ |
54 | static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */ | |
55 | static int shuffle_interval = 5; /* Interval between shuffles (in sec)*/ | |
72e9bb54 | 56 | static char *torture_type = "rcu"; /* What to torture. */ |
a241ec65 | 57 | |
8d3b33f6 | 58 | module_param(nreaders, int, 0); |
a241ec65 | 59 | MODULE_PARM_DESC(nreaders, "Number of RCU reader threads"); |
8d3b33f6 | 60 | module_param(stat_interval, int, 0); |
a241ec65 | 61 | MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s"); |
8d3b33f6 | 62 | module_param(verbose, bool, 0); |
a241ec65 | 63 | MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s"); |
8d3b33f6 | 64 | module_param(test_no_idle_hz, bool, 0); |
d84f5203 | 65 | MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs"); |
8d3b33f6 | 66 | module_param(shuffle_interval, int, 0); |
d84f5203 | 67 | MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles"); |
72e9bb54 PM |
68 | module_param(torture_type, charp, 0); |
69 | MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu)"); | |
70 | ||
71 | #define TORTURE_FLAG "-torture:" | |
a241ec65 | 72 | #define PRINTK_STRING(s) \ |
72e9bb54 | 73 | do { printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0) |
a241ec65 | 74 | #define VERBOSE_PRINTK_STRING(s) \ |
72e9bb54 | 75 | do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG s "\n", torture_type); } while (0) |
a241ec65 | 76 | #define VERBOSE_PRINTK_ERRSTRING(s) \ |
72e9bb54 | 77 | do { if (verbose) printk(KERN_ALERT "%s" TORTURE_FLAG "!!! " s "\n", torture_type); } while (0) |
a241ec65 PM |
78 | |
79 | static char printk_buf[4096]; | |
80 | ||
81 | static int nrealreaders; | |
82 | static struct task_struct *writer_task; | |
83 | static struct task_struct **reader_tasks; | |
84 | static struct task_struct *stats_task; | |
d84f5203 | 85 | static struct task_struct *shuffler_task; |
a241ec65 PM |
86 | |
87 | #define RCU_TORTURE_PIPE_LEN 10 | |
88 | ||
89 | struct rcu_torture { | |
90 | struct rcu_head rtort_rcu; | |
91 | int rtort_pipe_count; | |
92 | struct list_head rtort_free; | |
996417d2 | 93 | int rtort_mbtest; |
a241ec65 PM |
94 | }; |
95 | ||
96 | static int fullstop = 0; /* stop generating callbacks at test end. */ | |
97 | static LIST_HEAD(rcu_torture_freelist); | |
98 | static struct rcu_torture *rcu_torture_current = NULL; | |
99 | static long rcu_torture_current_version = 0; | |
100 | static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN]; | |
101 | static DEFINE_SPINLOCK(rcu_torture_lock); | |
102 | static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) = | |
103 | { 0 }; | |
104 | static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) = | |
105 | { 0 }; | |
106 | static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1]; | |
107 | atomic_t n_rcu_torture_alloc; | |
108 | atomic_t n_rcu_torture_alloc_fail; | |
109 | atomic_t n_rcu_torture_free; | |
996417d2 PM |
110 | atomic_t n_rcu_torture_mberror; |
111 | atomic_t n_rcu_torture_error; | |
a241ec65 PM |
112 | |
113 | /* | |
114 | * Allocate an element from the rcu_tortures pool. | |
115 | */ | |
97a41e26 | 116 | static struct rcu_torture * |
a241ec65 PM |
117 | rcu_torture_alloc(void) |
118 | { | |
119 | struct list_head *p; | |
120 | ||
adac1665 | 121 | spin_lock_bh(&rcu_torture_lock); |
a241ec65 PM |
122 | if (list_empty(&rcu_torture_freelist)) { |
123 | atomic_inc(&n_rcu_torture_alloc_fail); | |
adac1665 | 124 | spin_unlock_bh(&rcu_torture_lock); |
a241ec65 PM |
125 | return NULL; |
126 | } | |
127 | atomic_inc(&n_rcu_torture_alloc); | |
128 | p = rcu_torture_freelist.next; | |
129 | list_del_init(p); | |
adac1665 | 130 | spin_unlock_bh(&rcu_torture_lock); |
a241ec65 PM |
131 | return container_of(p, struct rcu_torture, rtort_free); |
132 | } | |
133 | ||
134 | /* | |
135 | * Free an element to the rcu_tortures pool. | |
136 | */ | |
137 | static void | |
138 | rcu_torture_free(struct rcu_torture *p) | |
139 | { | |
140 | atomic_inc(&n_rcu_torture_free); | |
adac1665 | 141 | spin_lock_bh(&rcu_torture_lock); |
a241ec65 | 142 | list_add_tail(&p->rtort_free, &rcu_torture_freelist); |
adac1665 | 143 | spin_unlock_bh(&rcu_torture_lock); |
a241ec65 PM |
144 | } |
145 | ||
a241ec65 PM |
146 | struct rcu_random_state { |
147 | unsigned long rrs_state; | |
148 | unsigned long rrs_count; | |
149 | }; | |
150 | ||
151 | #define RCU_RANDOM_MULT 39916801 /* prime */ | |
152 | #define RCU_RANDOM_ADD 479001701 /* prime */ | |
153 | #define RCU_RANDOM_REFRESH 10000 | |
154 | ||
155 | #define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 } | |
156 | ||
157 | /* | |
158 | * Crude but fast random-number generator. Uses a linear congruential | |
159 | * generator, with occasional help from get_random_bytes(). | |
160 | */ | |
161 | static long | |
162 | rcu_random(struct rcu_random_state *rrsp) | |
163 | { | |
164 | long refresh; | |
165 | ||
166 | if (--rrsp->rrs_count < 0) { | |
167 | get_random_bytes(&refresh, sizeof(refresh)); | |
168 | rrsp->rrs_state += refresh; | |
169 | rrsp->rrs_count = RCU_RANDOM_REFRESH; | |
170 | } | |
171 | rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD; | |
172 | return swahw32(rrsp->rrs_state); | |
173 | } | |
174 | ||
72e9bb54 PM |
175 | /* |
176 | * Operations vector for selecting different types of tests. | |
177 | */ | |
178 | ||
179 | struct rcu_torture_ops { | |
180 | void (*init)(void); | |
181 | void (*cleanup)(void); | |
182 | int (*readlock)(void); | |
183 | void (*readunlock)(int idx); | |
184 | int (*completed)(void); | |
185 | void (*deferredfree)(struct rcu_torture *p); | |
186 | int (*stats)(char *page); | |
187 | char *name; | |
188 | }; | |
189 | static struct rcu_torture_ops *cur_ops = NULL; | |
190 | ||
191 | /* | |
192 | * Definitions for rcu torture testing. | |
193 | */ | |
194 | ||
195 | static int rcu_torture_read_lock(void) | |
196 | { | |
197 | rcu_read_lock(); | |
198 | return 0; | |
199 | } | |
200 | ||
201 | static void rcu_torture_read_unlock(int idx) | |
202 | { | |
203 | rcu_read_unlock(); | |
204 | } | |
205 | ||
206 | static int rcu_torture_completed(void) | |
207 | { | |
208 | return rcu_batches_completed(); | |
209 | } | |
210 | ||
211 | static void | |
212 | rcu_torture_cb(struct rcu_head *p) | |
213 | { | |
214 | int i; | |
215 | struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu); | |
216 | ||
217 | if (fullstop) { | |
218 | /* Test is ending, just drop callbacks on the floor. */ | |
219 | /* The next initialization will pick up the pieces. */ | |
220 | return; | |
221 | } | |
222 | i = rp->rtort_pipe_count; | |
223 | if (i > RCU_TORTURE_PIPE_LEN) | |
224 | i = RCU_TORTURE_PIPE_LEN; | |
225 | atomic_inc(&rcu_torture_wcount[i]); | |
226 | if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) { | |
227 | rp->rtort_mbtest = 0; | |
228 | rcu_torture_free(rp); | |
229 | } else | |
230 | cur_ops->deferredfree(rp); | |
231 | } | |
232 | ||
233 | static void rcu_torture_deferred_free(struct rcu_torture *p) | |
234 | { | |
235 | call_rcu(&p->rtort_rcu, rcu_torture_cb); | |
236 | } | |
237 | ||
238 | static struct rcu_torture_ops rcu_ops = { | |
239 | .init = NULL, | |
240 | .cleanup = NULL, | |
241 | .readlock = rcu_torture_read_lock, | |
242 | .readunlock = rcu_torture_read_unlock, | |
243 | .completed = rcu_torture_completed, | |
244 | .deferredfree = rcu_torture_deferred_free, | |
245 | .stats = NULL, | |
246 | .name = "rcu" | |
247 | }; | |
248 | ||
249 | static struct rcu_torture_ops *torture_ops[] = | |
250 | { &rcu_ops, NULL }; | |
251 | ||
a241ec65 PM |
252 | /* |
253 | * RCU torture writer kthread. Repeatedly substitutes a new structure | |
254 | * for that pointed to by rcu_torture_current, freeing the old structure | |
255 | * after a series of grace periods (the "pipeline"). | |
256 | */ | |
257 | static int | |
258 | rcu_torture_writer(void *arg) | |
259 | { | |
260 | int i; | |
261 | long oldbatch = rcu_batches_completed(); | |
262 | struct rcu_torture *rp; | |
263 | struct rcu_torture *old_rp; | |
264 | static DEFINE_RCU_RANDOM(rand); | |
265 | ||
266 | VERBOSE_PRINTK_STRING("rcu_torture_writer task started"); | |
dbdf65b1 IM |
267 | set_user_nice(current, 19); |
268 | ||
a241ec65 PM |
269 | do { |
270 | schedule_timeout_uninterruptible(1); | |
a241ec65 PM |
271 | if ((rp = rcu_torture_alloc()) == NULL) |
272 | continue; | |
273 | rp->rtort_pipe_count = 0; | |
274 | udelay(rcu_random(&rand) & 0x3ff); | |
275 | old_rp = rcu_torture_current; | |
996417d2 | 276 | rp->rtort_mbtest = 1; |
a241ec65 PM |
277 | rcu_assign_pointer(rcu_torture_current, rp); |
278 | smp_wmb(); | |
279 | if (old_rp != NULL) { | |
280 | i = old_rp->rtort_pipe_count; | |
281 | if (i > RCU_TORTURE_PIPE_LEN) | |
282 | i = RCU_TORTURE_PIPE_LEN; | |
283 | atomic_inc(&rcu_torture_wcount[i]); | |
284 | old_rp->rtort_pipe_count++; | |
72e9bb54 | 285 | cur_ops->deferredfree(old_rp); |
a241ec65 PM |
286 | } |
287 | rcu_torture_current_version++; | |
72e9bb54 | 288 | oldbatch = cur_ops->completed(); |
a241ec65 PM |
289 | } while (!kthread_should_stop() && !fullstop); |
290 | VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping"); | |
291 | while (!kthread_should_stop()) | |
292 | schedule_timeout_uninterruptible(1); | |
293 | return 0; | |
294 | } | |
295 | ||
296 | /* | |
297 | * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current, | |
298 | * incrementing the corresponding element of the pipeline array. The | |
299 | * counter in the element should never be greater than 1, otherwise, the | |
300 | * RCU implementation is broken. | |
301 | */ | |
302 | static int | |
303 | rcu_torture_reader(void *arg) | |
304 | { | |
305 | int completed; | |
72e9bb54 | 306 | int idx; |
a241ec65 PM |
307 | DEFINE_RCU_RANDOM(rand); |
308 | struct rcu_torture *p; | |
309 | int pipe_count; | |
310 | ||
311 | VERBOSE_PRINTK_STRING("rcu_torture_reader task started"); | |
dbdf65b1 IM |
312 | set_user_nice(current, 19); |
313 | ||
a241ec65 | 314 | do { |
72e9bb54 PM |
315 | idx = cur_ops->readlock(); |
316 | completed = cur_ops->completed(); | |
a241ec65 PM |
317 | p = rcu_dereference(rcu_torture_current); |
318 | if (p == NULL) { | |
319 | /* Wait for rcu_torture_writer to get underway */ | |
72e9bb54 | 320 | cur_ops->readunlock(idx); |
a241ec65 PM |
321 | schedule_timeout_interruptible(HZ); |
322 | continue; | |
323 | } | |
996417d2 PM |
324 | if (p->rtort_mbtest == 0) |
325 | atomic_inc(&n_rcu_torture_mberror); | |
a241ec65 PM |
326 | udelay(rcu_random(&rand) & 0x7f); |
327 | preempt_disable(); | |
328 | pipe_count = p->rtort_pipe_count; | |
329 | if (pipe_count > RCU_TORTURE_PIPE_LEN) { | |
330 | /* Should not happen, but... */ | |
331 | pipe_count = RCU_TORTURE_PIPE_LEN; | |
332 | } | |
333 | ++__get_cpu_var(rcu_torture_count)[pipe_count]; | |
72e9bb54 | 334 | completed = cur_ops->completed() - completed; |
a241ec65 PM |
335 | if (completed > RCU_TORTURE_PIPE_LEN) { |
336 | /* Should not happen, but... */ | |
337 | completed = RCU_TORTURE_PIPE_LEN; | |
338 | } | |
339 | ++__get_cpu_var(rcu_torture_batch)[completed]; | |
340 | preempt_enable(); | |
72e9bb54 | 341 | cur_ops->readunlock(idx); |
a241ec65 PM |
342 | schedule(); |
343 | } while (!kthread_should_stop() && !fullstop); | |
344 | VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping"); | |
345 | while (!kthread_should_stop()) | |
346 | schedule_timeout_uninterruptible(1); | |
347 | return 0; | |
348 | } | |
349 | ||
350 | /* | |
351 | * Create an RCU-torture statistics message in the specified buffer. | |
352 | */ | |
353 | static int | |
354 | rcu_torture_printk(char *page) | |
355 | { | |
356 | int cnt = 0; | |
357 | int cpu; | |
358 | int i; | |
359 | long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; | |
360 | long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 }; | |
361 | ||
0a945022 | 362 | for_each_possible_cpu(cpu) { |
a241ec65 PM |
363 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { |
364 | pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i]; | |
365 | batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i]; | |
366 | } | |
367 | } | |
368 | for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) { | |
369 | if (pipesummary[i] != 0) | |
370 | break; | |
371 | } | |
72e9bb54 | 372 | cnt += sprintf(&page[cnt], "%s%s ", torture_type, TORTURE_FLAG); |
a241ec65 | 373 | cnt += sprintf(&page[cnt], |
996417d2 PM |
374 | "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d " |
375 | "rtmbe: %d", | |
a241ec65 PM |
376 | rcu_torture_current, |
377 | rcu_torture_current_version, | |
378 | list_empty(&rcu_torture_freelist), | |
379 | atomic_read(&n_rcu_torture_alloc), | |
380 | atomic_read(&n_rcu_torture_alloc_fail), | |
996417d2 PM |
381 | atomic_read(&n_rcu_torture_free), |
382 | atomic_read(&n_rcu_torture_mberror)); | |
383 | if (atomic_read(&n_rcu_torture_mberror) != 0) | |
384 | cnt += sprintf(&page[cnt], " !!!"); | |
72e9bb54 | 385 | cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); |
996417d2 | 386 | if (i > 1) { |
a241ec65 | 387 | cnt += sprintf(&page[cnt], "!!! "); |
996417d2 PM |
388 | atomic_inc(&n_rcu_torture_error); |
389 | } | |
a241ec65 PM |
390 | cnt += sprintf(&page[cnt], "Reader Pipe: "); |
391 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) | |
392 | cnt += sprintf(&page[cnt], " %ld", pipesummary[i]); | |
72e9bb54 | 393 | cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); |
a241ec65 | 394 | cnt += sprintf(&page[cnt], "Reader Batch: "); |
72e9bb54 | 395 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) |
a241ec65 | 396 | cnt += sprintf(&page[cnt], " %ld", batchsummary[i]); |
72e9bb54 | 397 | cnt += sprintf(&page[cnt], "\n%s%s ", torture_type, TORTURE_FLAG); |
a241ec65 PM |
398 | cnt += sprintf(&page[cnt], "Free-Block Circulation: "); |
399 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { | |
400 | cnt += sprintf(&page[cnt], " %d", | |
401 | atomic_read(&rcu_torture_wcount[i])); | |
402 | } | |
403 | cnt += sprintf(&page[cnt], "\n"); | |
72e9bb54 PM |
404 | if (cur_ops->stats != NULL) |
405 | cnt += cur_ops->stats(&page[cnt]); | |
a241ec65 PM |
406 | return cnt; |
407 | } | |
408 | ||
409 | /* | |
410 | * Print torture statistics. Caller must ensure that there is only | |
411 | * one call to this function at a given time!!! This is normally | |
412 | * accomplished by relying on the module system to only have one copy | |
413 | * of the module loaded, and then by giving the rcu_torture_stats | |
414 | * kthread full control (or the init/cleanup functions when rcu_torture_stats | |
415 | * thread is not running). | |
416 | */ | |
417 | static void | |
418 | rcu_torture_stats_print(void) | |
419 | { | |
420 | int cnt; | |
421 | ||
422 | cnt = rcu_torture_printk(printk_buf); | |
423 | printk(KERN_ALERT "%s", printk_buf); | |
424 | } | |
425 | ||
426 | /* | |
427 | * Periodically prints torture statistics, if periodic statistics printing | |
428 | * was specified via the stat_interval module parameter. | |
429 | * | |
430 | * No need to worry about fullstop here, since this one doesn't reference | |
431 | * volatile state or register callbacks. | |
432 | */ | |
433 | static int | |
434 | rcu_torture_stats(void *arg) | |
435 | { | |
436 | VERBOSE_PRINTK_STRING("rcu_torture_stats task started"); | |
437 | do { | |
438 | schedule_timeout_interruptible(stat_interval * HZ); | |
439 | rcu_torture_stats_print(); | |
440 | } while (!kthread_should_stop()); | |
441 | VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping"); | |
442 | return 0; | |
443 | } | |
444 | ||
d84f5203 SV |
445 | static int rcu_idle_cpu; /* Force all torture tasks off this CPU */ |
446 | ||
447 | /* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case | |
448 | * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs. | |
449 | */ | |
450 | void rcu_torture_shuffle_tasks(void) | |
451 | { | |
452 | cpumask_t tmp_mask = CPU_MASK_ALL; | |
453 | int i; | |
454 | ||
455 | lock_cpu_hotplug(); | |
456 | ||
457 | /* No point in shuffling if there is only one online CPU (ex: UP) */ | |
458 | if (num_online_cpus() == 1) { | |
459 | unlock_cpu_hotplug(); | |
460 | return; | |
461 | } | |
462 | ||
463 | if (rcu_idle_cpu != -1) | |
464 | cpu_clear(rcu_idle_cpu, tmp_mask); | |
465 | ||
466 | set_cpus_allowed(current, tmp_mask); | |
467 | ||
468 | if (reader_tasks != NULL) { | |
469 | for (i = 0; i < nrealreaders; i++) | |
470 | if (reader_tasks[i]) | |
471 | set_cpus_allowed(reader_tasks[i], tmp_mask); | |
472 | } | |
473 | ||
474 | if (writer_task) | |
475 | set_cpus_allowed(writer_task, tmp_mask); | |
476 | ||
477 | if (stats_task) | |
478 | set_cpus_allowed(stats_task, tmp_mask); | |
479 | ||
480 | if (rcu_idle_cpu == -1) | |
481 | rcu_idle_cpu = num_online_cpus() - 1; | |
482 | else | |
483 | rcu_idle_cpu--; | |
484 | ||
485 | unlock_cpu_hotplug(); | |
486 | } | |
487 | ||
488 | /* Shuffle tasks across CPUs, with the intent of allowing each CPU in the | |
489 | * system to become idle at a time and cut off its timer ticks. This is meant | |
490 | * to test the support for such tickless idle CPU in RCU. | |
491 | */ | |
492 | static int | |
493 | rcu_torture_shuffle(void *arg) | |
494 | { | |
495 | VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started"); | |
496 | do { | |
497 | schedule_timeout_interruptible(shuffle_interval * HZ); | |
498 | rcu_torture_shuffle_tasks(); | |
499 | } while (!kthread_should_stop()); | |
500 | VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping"); | |
501 | return 0; | |
502 | } | |
503 | ||
95c38322 PM |
504 | static inline void |
505 | rcu_torture_print_module_parms(char *tag) | |
506 | { | |
72e9bb54 | 507 | printk(KERN_ALERT "%s" TORTURE_FLAG "--- %s: nreaders=%d " |
95c38322 PM |
508 | "stat_interval=%d verbose=%d test_no_idle_hz=%d " |
509 | "shuffle_interval = %d\n", | |
72e9bb54 PM |
510 | torture_type, tag, nrealreaders, stat_interval, verbose, |
511 | test_no_idle_hz, shuffle_interval); | |
95c38322 PM |
512 | } |
513 | ||
a241ec65 PM |
514 | static void |
515 | rcu_torture_cleanup(void) | |
516 | { | |
517 | int i; | |
518 | ||
519 | fullstop = 1; | |
d84f5203 SV |
520 | if (shuffler_task != NULL) { |
521 | VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task"); | |
522 | kthread_stop(shuffler_task); | |
523 | } | |
524 | shuffler_task = NULL; | |
525 | ||
a241ec65 PM |
526 | if (writer_task != NULL) { |
527 | VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task"); | |
528 | kthread_stop(writer_task); | |
529 | } | |
530 | writer_task = NULL; | |
531 | ||
532 | if (reader_tasks != NULL) { | |
533 | for (i = 0; i < nrealreaders; i++) { | |
534 | if (reader_tasks[i] != NULL) { | |
535 | VERBOSE_PRINTK_STRING( | |
536 | "Stopping rcu_torture_reader task"); | |
537 | kthread_stop(reader_tasks[i]); | |
538 | } | |
539 | reader_tasks[i] = NULL; | |
540 | } | |
541 | kfree(reader_tasks); | |
542 | reader_tasks = NULL; | |
543 | } | |
544 | rcu_torture_current = NULL; | |
545 | ||
546 | if (stats_task != NULL) { | |
547 | VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task"); | |
548 | kthread_stop(stats_task); | |
549 | } | |
550 | stats_task = NULL; | |
551 | ||
552 | /* Wait for all RCU callbacks to fire. */ | |
89d46b87 | 553 | rcu_barrier(); |
a241ec65 | 554 | |
a241ec65 | 555 | rcu_torture_stats_print(); /* -After- the stats thread is stopped! */ |
72e9bb54 PM |
556 | |
557 | if (cur_ops->cleanup != NULL) | |
558 | cur_ops->cleanup(); | |
95c38322 PM |
559 | if (atomic_read(&n_rcu_torture_error)) |
560 | rcu_torture_print_module_parms("End of test: FAILURE"); | |
561 | else | |
562 | rcu_torture_print_module_parms("End of test: SUCCESS"); | |
a241ec65 PM |
563 | } |
564 | ||
565 | static int | |
566 | rcu_torture_init(void) | |
567 | { | |
568 | int i; | |
569 | int cpu; | |
570 | int firsterr = 0; | |
571 | ||
572 | /* Process args and tell the world that the torturer is on the job. */ | |
573 | ||
72e9bb54 PM |
574 | for (i = 0; cur_ops = torture_ops[i], cur_ops != NULL; i++) { |
575 | cur_ops = torture_ops[i]; | |
576 | if (strcmp(torture_type, cur_ops->name) == 0) { | |
577 | break; | |
578 | } | |
579 | } | |
580 | if (cur_ops == NULL) { | |
581 | printk(KERN_ALERT "rcutorture: invalid torture type: \"%s\"\n", | |
582 | torture_type); | |
583 | return (-EINVAL); | |
584 | } | |
585 | if (cur_ops->init != NULL) | |
586 | cur_ops->init(); /* no "goto unwind" prior to this point!!! */ | |
587 | ||
a241ec65 PM |
588 | if (nreaders >= 0) |
589 | nrealreaders = nreaders; | |
590 | else | |
591 | nrealreaders = 2 * num_online_cpus(); | |
95c38322 | 592 | rcu_torture_print_module_parms("Start of test"); |
a241ec65 PM |
593 | fullstop = 0; |
594 | ||
595 | /* Set up the freelist. */ | |
596 | ||
597 | INIT_LIST_HEAD(&rcu_torture_freelist); | |
598 | for (i = 0; i < sizeof(rcu_tortures) / sizeof(rcu_tortures[0]); i++) { | |
996417d2 | 599 | rcu_tortures[i].rtort_mbtest = 0; |
a241ec65 PM |
600 | list_add_tail(&rcu_tortures[i].rtort_free, |
601 | &rcu_torture_freelist); | |
602 | } | |
603 | ||
604 | /* Initialize the statistics so that each run gets its own numbers. */ | |
605 | ||
606 | rcu_torture_current = NULL; | |
607 | rcu_torture_current_version = 0; | |
608 | atomic_set(&n_rcu_torture_alloc, 0); | |
609 | atomic_set(&n_rcu_torture_alloc_fail, 0); | |
610 | atomic_set(&n_rcu_torture_free, 0); | |
996417d2 PM |
611 | atomic_set(&n_rcu_torture_mberror, 0); |
612 | atomic_set(&n_rcu_torture_error, 0); | |
a241ec65 PM |
613 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) |
614 | atomic_set(&rcu_torture_wcount[i], 0); | |
0a945022 | 615 | for_each_possible_cpu(cpu) { |
a241ec65 PM |
616 | for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) { |
617 | per_cpu(rcu_torture_count, cpu)[i] = 0; | |
618 | per_cpu(rcu_torture_batch, cpu)[i] = 0; | |
619 | } | |
620 | } | |
621 | ||
622 | /* Start up the kthreads. */ | |
623 | ||
624 | VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task"); | |
625 | writer_task = kthread_run(rcu_torture_writer, NULL, | |
626 | "rcu_torture_writer"); | |
627 | if (IS_ERR(writer_task)) { | |
628 | firsterr = PTR_ERR(writer_task); | |
629 | VERBOSE_PRINTK_ERRSTRING("Failed to create writer"); | |
630 | writer_task = NULL; | |
631 | goto unwind; | |
632 | } | |
633 | reader_tasks = kmalloc(nrealreaders * sizeof(reader_tasks[0]), | |
634 | GFP_KERNEL); | |
635 | if (reader_tasks == NULL) { | |
636 | VERBOSE_PRINTK_ERRSTRING("out of memory"); | |
637 | firsterr = -ENOMEM; | |
638 | goto unwind; | |
639 | } | |
640 | for (i = 0; i < nrealreaders; i++) { | |
641 | VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task"); | |
642 | reader_tasks[i] = kthread_run(rcu_torture_reader, NULL, | |
643 | "rcu_torture_reader"); | |
644 | if (IS_ERR(reader_tasks[i])) { | |
645 | firsterr = PTR_ERR(reader_tasks[i]); | |
646 | VERBOSE_PRINTK_ERRSTRING("Failed to create reader"); | |
647 | reader_tasks[i] = NULL; | |
648 | goto unwind; | |
649 | } | |
650 | } | |
651 | if (stat_interval > 0) { | |
652 | VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task"); | |
653 | stats_task = kthread_run(rcu_torture_stats, NULL, | |
654 | "rcu_torture_stats"); | |
655 | if (IS_ERR(stats_task)) { | |
656 | firsterr = PTR_ERR(stats_task); | |
657 | VERBOSE_PRINTK_ERRSTRING("Failed to create stats"); | |
658 | stats_task = NULL; | |
659 | goto unwind; | |
660 | } | |
661 | } | |
d84f5203 SV |
662 | if (test_no_idle_hz) { |
663 | rcu_idle_cpu = num_online_cpus() - 1; | |
664 | /* Create the shuffler thread */ | |
665 | shuffler_task = kthread_run(rcu_torture_shuffle, NULL, | |
666 | "rcu_torture_shuffle"); | |
667 | if (IS_ERR(shuffler_task)) { | |
668 | firsterr = PTR_ERR(shuffler_task); | |
669 | VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler"); | |
670 | shuffler_task = NULL; | |
671 | goto unwind; | |
672 | } | |
673 | } | |
a241ec65 PM |
674 | return 0; |
675 | ||
676 | unwind: | |
677 | rcu_torture_cleanup(); | |
678 | return firsterr; | |
679 | } | |
680 | ||
681 | module_init(rcu_torture_init); | |
682 | module_exit(rcu_torture_cleanup); |