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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-02-04 18:51:41 -0500
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-02-23 12:04:29 -0500
commit0af3fe1efa534a43385fe2694c42ffec7a310e46 (patch)
tree32a167b7b5cae8a461569ca5b58433b1400ac5b8 /kernel/locking
parent2193e1604eac422df05f77b53667237fcf130bf5 (diff)
locktorture: Add a lock-torture kernel module
This commit adds the locking counterpart to rcutorture. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Make n_lock_torture_errors and torture_spinlock static as suggested by Fengguang Wu. ] Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/Makefile1
-rw-r--r--kernel/locking/locktorture.c421
2 files changed, 422 insertions, 0 deletions
diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index baab8e5e7f66..a28ea6d9e6e8 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -23,3 +23,4 @@ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
23obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o 23obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
24obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o 24obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
25obj-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o 25obj-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
26obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
new file mode 100644
index 000000000000..d69d20d9c9db
--- /dev/null
+++ b/kernel/locking/locktorture.c
@@ -0,0 +1,421 @@
1/*
2 * Module-based torture test facility for locking
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, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
17 *
18 * Copyright (C) IBM Corporation, 2014
19 *
20 * Author: Paul E. McKenney <paulmck@us.ibm.com>
21 * Based on kernel/rcu/torture.c.
22 */
23#include <linux/types.h>
24#include <linux/kernel.h>
25#include <linux/init.h>
26#include <linux/module.h>
27#include <linux/kthread.h>
28#include <linux/err.h>
29#include <linux/spinlock.h>
30#include <linux/smp.h>
31#include <linux/interrupt.h>
32#include <linux/sched.h>
33#include <linux/atomic.h>
34#include <linux/bitops.h>
35#include <linux/completion.h>
36#include <linux/moduleparam.h>
37#include <linux/percpu.h>
38#include <linux/notifier.h>
39#include <linux/reboot.h>
40#include <linux/freezer.h>
41#include <linux/cpu.h>
42#include <linux/delay.h>
43#include <linux/stat.h>
44#include <linux/slab.h>
45#include <linux/trace_clock.h>
46#include <asm/byteorder.h>
47#include <linux/torture.h>
48
49MODULE_LICENSE("GPL");
50MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");
51
52torture_param(int, nwriters_stress, -1,
53 "Number of write-locking stress-test threads");
54torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
55torture_param(int, onoff_interval, 0,
56 "Time between CPU hotplugs (s), 0=disable");
57torture_param(int, shuffle_interval, 3,
58 "Number of jiffies between shuffles, 0=disable");
59torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable.");
60torture_param(int, stat_interval, 60,
61 "Number of seconds between stats printk()s");
62torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
63torture_param(bool, verbose, true,
64 "Enable verbose debugging printk()s");
65
66static char *torture_type = "spin_lock";
67module_param(torture_type, charp, 0444);
68MODULE_PARM_DESC(torture_type,
69 "Type of lock to torture (spin_lock, spin_lock_irq, ...)");
70
71static atomic_t n_lock_torture_errors;
72
73static struct task_struct *stats_task;
74static struct task_struct **writer_tasks;
75
76static int nrealwriters_stress;
77static bool lock_is_write_held;
78
79struct lock_writer_stress_stats {
80 long n_write_lock_fail;
81 long n_write_lock_acquired;
82};
83static struct lock_writer_stress_stats *lwsa;
84
85#if defined(MODULE) || defined(CONFIG_LOCK_TORTURE_TEST_RUNNABLE)
86#define LOCKTORTURE_RUNNABLE_INIT 1
87#else
88#define LOCKTORTURE_RUNNABLE_INIT 0
89#endif
90int locktorture_runnable = LOCKTORTURE_RUNNABLE_INIT;
91module_param(locktorture_runnable, int, 0444);
92MODULE_PARM_DESC(locktorture_runnable, "Start locktorture at boot");
93
94/* Forward reference. */
95static void lock_torture_cleanup(void);
96
97/*
98 * Operations vector for selecting different types of tests.
99 */
100struct lock_torture_ops {
101 void (*init)(void);
102 int (*writelock)(void);
103 void (*write_delay)(struct torture_random_state *trsp);
104 void (*writeunlock)(void);
105 unsigned long flags;
106 const char *name;
107};
108
109static struct lock_torture_ops *cur_ops;
110
111/*
112 * Definitions for lock torture testing.
113 */
114
115static DEFINE_SPINLOCK(torture_spinlock);
116
117static int torture_spin_lock_write_lock(void) __acquires(torture_spinlock)
118{
119 spin_lock(&torture_spinlock);
120 return 0;
121}
122
123static void torture_spin_lock_write_delay(struct torture_random_state *trsp)
124{
125 const unsigned long shortdelay_us = 2;
126 const unsigned long longdelay_us = 100;
127
128 /* We want a short delay mostly to emulate likely code, and
129 * we want a long delay occasionally to force massive contention.
130 */
131 if (!(torture_random(trsp) %
132 (nrealwriters_stress * 2000 * longdelay_us)))
133 mdelay(longdelay_us);
134 if (!(torture_random(trsp) %
135 (nrealwriters_stress * 2 * shortdelay_us)))
136 udelay(shortdelay_us);
137#ifdef CONFIG_PREEMPT
138 if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))
139 preempt_schedule(); /* Allow test to be preempted. */
140#endif
141}
142
143static void torture_spin_lock_write_unlock(void) __releases(torture_spinlock)
144{
145 spin_unlock(&torture_spinlock);
146}
147
148static struct lock_torture_ops spin_lock_ops = {
149 .writelock = torture_spin_lock_write_lock,
150 .write_delay = torture_spin_lock_write_delay,
151 .writeunlock = torture_spin_lock_write_unlock,
152 .name = "spin_lock"
153};
154
155static int torture_spin_lock_write_lock_irq(void)
156__acquires(torture_spinlock_irq)
157{
158 unsigned long flags;
159
160 spin_lock_irqsave(&torture_spinlock, flags);
161 cur_ops->flags = flags;
162 return 0;
163}
164
165static void torture_lock_spin_write_unlock_irq(void)
166__releases(torture_spinlock)
167{
168 spin_unlock_irqrestore(&torture_spinlock, cur_ops->flags);
169}
170
171static struct lock_torture_ops spin_lock_irq_ops = {
172 .writelock = torture_spin_lock_write_lock_irq,
173 .write_delay = torture_spin_lock_write_delay,
174 .writeunlock = torture_lock_spin_write_unlock_irq,
175 .name = "spin_lock_irq"
176};
177
178/*
179 * Lock torture writer kthread. Repeatedly acquires and releases
180 * the lock, checking for duplicate acquisitions.
181 */
182static int lock_torture_writer(void *arg)
183{
184 struct lock_writer_stress_stats *lwsp = arg;
185 static DEFINE_TORTURE_RANDOM(rand);
186
187 VERBOSE_TOROUT_STRING("lock_torture_writer task started");
188 set_user_nice(current, 19);
189
190 do {
191 schedule_timeout_uninterruptible(1);
192 cur_ops->writelock();
193 if (WARN_ON_ONCE(lock_is_write_held))
194 lwsp->n_write_lock_fail++;
195 lock_is_write_held = 1;
196 lwsp->n_write_lock_acquired++;
197 cur_ops->write_delay(&rand);
198 lock_is_write_held = 0;
199 cur_ops->writeunlock();
200 stutter_wait("lock_torture_writer");
201 } while (!torture_must_stop());
202 torture_kthread_stopping("lock_torture_writer");
203 return 0;
204}
205
206/*
207 * Create an lock-torture-statistics message in the specified buffer.
208 */
209static void lock_torture_printk(char *page)
210{
211 bool fail = 0;
212 int i;
213 long max = 0;
214 long min = lwsa[0].n_write_lock_acquired;
215 long long sum = 0;
216
217 for (i = 0; i < nrealwriters_stress; i++) {
218 if (lwsa[i].n_write_lock_fail)
219 fail = true;
220 sum += lwsa[i].n_write_lock_acquired;
221 if (max < lwsa[i].n_write_lock_fail)
222 max = lwsa[i].n_write_lock_fail;
223 if (min > lwsa[i].n_write_lock_fail)
224 min = lwsa[i].n_write_lock_fail;
225 }
226 page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
227 page += sprintf(page,
228 "Writes: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
229 sum, max, min, max / 2 > min ? "???" : "",
230 fail, fail ? "!!!" : "");
231 if (fail)
232 atomic_inc(&n_lock_torture_errors);
233}
234
235/*
236 * Print torture statistics. Caller must ensure that there is only one
237 * call to this function at a given time!!! This is normally accomplished
238 * by relying on the module system to only have one copy of the module
239 * loaded, and then by giving the lock_torture_stats kthread full control
240 * (or the init/cleanup functions when lock_torture_stats thread is not
241 * running).
242 */
243static void lock_torture_stats_print(void)
244{
245 int size = nrealwriters_stress * 200 + 8192;
246 char *buf;
247
248 buf = kmalloc(size, GFP_KERNEL);
249 if (!buf) {
250 pr_err("lock_torture_stats_print: Out of memory, need: %d",
251 size);
252 return;
253 }
254 lock_torture_printk(buf);
255 pr_alert("%s", buf);
256 kfree(buf);
257}
258
259/*
260 * Periodically prints torture statistics, if periodic statistics printing
261 * was specified via the stat_interval module parameter.
262 *
263 * No need to worry about fullstop here, since this one doesn't reference
264 * volatile state or register callbacks.
265 */
266static int lock_torture_stats(void *arg)
267{
268 VERBOSE_TOROUT_STRING("lock_torture_stats task started");
269 do {
270 schedule_timeout_interruptible(stat_interval * HZ);
271 lock_torture_stats_print();
272 torture_shutdown_absorb("lock_torture_stats");
273 } while (!torture_must_stop());
274 torture_kthread_stopping("lock_torture_stats");
275 return 0;
276}
277
278static inline void
279lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
280 const char *tag)
281{
282 pr_alert("%s" TORTURE_FLAG
283 "--- %s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
284 torture_type, tag, nrealwriters_stress, stat_interval, verbose,
285 shuffle_interval, stutter, shutdown_secs,
286 onoff_interval, onoff_holdoff);
287}
288
289static void lock_torture_cleanup(void)
290{
291 int i;
292
293 if (torture_cleanup())
294 return;
295
296 if (writer_tasks) {
297 for (i = 0; i < nrealwriters_stress; i++)
298 torture_stop_kthread(lock_torture_writer,
299 writer_tasks[i]);
300 kfree(writer_tasks);
301 writer_tasks = NULL;
302 }
303
304 torture_stop_kthread(lock_torture_stats, stats_task);
305 lock_torture_stats_print(); /* -After- the stats thread is stopped! */
306
307 if (atomic_read(&n_lock_torture_errors))
308 lock_torture_print_module_parms(cur_ops,
309 "End of test: FAILURE");
310 else if (torture_onoff_failures())
311 lock_torture_print_module_parms(cur_ops,
312 "End of test: LOCK_HOTPLUG");
313 else
314 lock_torture_print_module_parms(cur_ops,
315 "End of test: SUCCESS");
316}
317
318static int __init lock_torture_init(void)
319{
320 int i;
321 int firsterr = 0;
322 static struct lock_torture_ops *torture_ops[] = {
323 &spin_lock_ops, &spin_lock_irq_ops,
324 };
325
326 torture_init_begin(torture_type, verbose, &locktorture_runnable);
327
328 /* Process args and tell the world that the torturer is on the job. */
329 for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
330 cur_ops = torture_ops[i];
331 if (strcmp(torture_type, cur_ops->name) == 0)
332 break;
333 }
334 if (i == ARRAY_SIZE(torture_ops)) {
335 pr_alert("lock-torture: invalid torture type: \"%s\"\n",
336 torture_type);
337 pr_alert("lock-torture types:");
338 for (i = 0; i < ARRAY_SIZE(torture_ops); i++)
339 pr_alert(" %s", torture_ops[i]->name);
340 pr_alert("\n");
341 torture_init_end();
342 return -EINVAL;
343 }
344 if (cur_ops->init)
345 cur_ops->init(); /* no "goto unwind" prior to this point!!! */
346
347 if (nwriters_stress >= 0)
348 nrealwriters_stress = nwriters_stress;
349 else
350 nrealwriters_stress = 2 * num_online_cpus();
351 lock_torture_print_module_parms(cur_ops, "Start of test");
352
353 /* Initialize the statistics so that each run gets its own numbers. */
354
355 lock_is_write_held = 0;
356 lwsa = kmalloc(sizeof(*lwsa) * nrealwriters_stress, GFP_KERNEL);
357 if (lwsa == NULL) {
358 VERBOSE_TOROUT_STRING("lwsa: Out of memory");
359 firsterr = -ENOMEM;
360 goto unwind;
361 }
362 for (i = 0; i < nrealwriters_stress; i++) {
363 lwsa[i].n_write_lock_fail = 0;
364 lwsa[i].n_write_lock_acquired = 0;
365 }
366
367 /* Start up the kthreads. */
368
369 if (onoff_interval > 0) {
370 firsterr = torture_onoff_init(onoff_holdoff * HZ,
371 onoff_interval * HZ);
372 if (firsterr)
373 goto unwind;
374 }
375 if (shuffle_interval > 0) {
376 firsterr = torture_shuffle_init(shuffle_interval);
377 if (firsterr)
378 goto unwind;
379 }
380 if (shutdown_secs > 0) {
381 firsterr = torture_shutdown_init(shutdown_secs,
382 lock_torture_cleanup);
383 if (firsterr)
384 goto unwind;
385 }
386 if (stutter > 0) {
387 firsterr = torture_stutter_init(stutter);
388 if (firsterr)
389 goto unwind;
390 }
391
392 writer_tasks = kzalloc(nrealwriters_stress * sizeof(writer_tasks[0]),
393 GFP_KERNEL);
394 if (writer_tasks == NULL) {
395 VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
396 firsterr = -ENOMEM;
397 goto unwind;
398 }
399 for (i = 0; i < nrealwriters_stress; i++) {
400 firsterr = torture_create_kthread(lock_torture_writer, &lwsa[i],
401 writer_tasks[i]);
402 if (firsterr)
403 goto unwind;
404 }
405 if (stat_interval > 0) {
406 firsterr = torture_create_kthread(lock_torture_stats, NULL,
407 stats_task);
408 if (firsterr)
409 goto unwind;
410 }
411 torture_init_end();
412 return 0;
413
414unwind:
415 torture_init_end();
416 lock_torture_cleanup();
417 return firsterr;
418}
419
420module_init(lock_torture_init);
421module_exit(lock_torture_cleanup);