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freeze_bdev: grab active reference to frozen superblocks
[linux-2.6/linux-2.6-openrd.git] / kernel / lockdep_proc.c
blobd4aba4f3584c73c3faff6ff5a0b73e27f6a7c5fb
1 /*
2 * kernel/lockdep_proc.c
3 *
4 * Runtime locking correctness validator
5 *
6 * Started by Ingo Molnar:
7 *
8 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
9 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
10 *
11 * Code for /proc/lockdep and /proc/lockdep_stats:
12 *
13 */
14 #include <linux/module.h>
15 #include <linux/proc_fs.h>
16 #include <linux/seq_file.h>
17 #include <linux/kallsyms.h>
18 #include <linux/debug_locks.h>
19 #include <linux/vmalloc.h>
20 #include <linux/sort.h>
21 #include <asm/uaccess.h>
22 #include <asm/div64.h>
23
24 #include "lockdep_internals.h"
25
26 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
27 {
28 return seq_list_next(v, &all_lock_classes, pos);
29 }
30
31 static void *l_start(struct seq_file *m, loff_t *pos)
32 {
33 return seq_list_start_head(&all_lock_classes, *pos);
34 }
35
36 static void l_stop(struct seq_file *m, void *v)
37 {
38 }
39
40 static void print_name(struct seq_file *m, struct lock_class *class)
41 {
42 char str[128];
43 const char *name = class->name;
44
45 if (!name) {
46 name = __get_key_name(class->key, str);
47 seq_printf(m, "%s", name);
48 } else{
49 seq_printf(m, "%s", name);
50 if (class->name_version > 1)
51 seq_printf(m, "#%d", class->name_version);
52 if (class->subclass)
53 seq_printf(m, "/%d", class->subclass);
54 }
55 }
56
57 static int l_show(struct seq_file *m, void *v)
58 {
59 struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
60 struct lock_list *entry;
61 char usage[LOCK_USAGE_CHARS];
62
63 if (v == &all_lock_classes) {
64 seq_printf(m, "all lock classes:\n");
65 return 0;
66 }
67
68 seq_printf(m, "%p", class->key);
69 #ifdef CONFIG_DEBUG_LOCKDEP
70 seq_printf(m, " OPS:%8ld", class->ops);
71 #endif
72 #ifdef CONFIG_PROVE_LOCKING
73 seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
74 seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
75 #endif
76
77 get_usage_chars(class, usage);
78 seq_printf(m, " %s", usage);
79
80 seq_printf(m, ": ");
81 print_name(m, class);
82 seq_puts(m, "\n");
83
84 list_for_each_entry(entry, &class->locks_after, entry) {
85 if (entry->distance == 1) {
86 seq_printf(m, " -> [%p] ", entry->class->key);
87 print_name(m, entry->class);
88 seq_puts(m, "\n");
89 }
90 }
91 seq_puts(m, "\n");
92
93 return 0;
94 }
95
96 static const struct seq_operations lockdep_ops = {
97 .start = l_start,
98 .next = l_next,
99 .stop = l_stop,
100 .show = l_show,
101 };
102
103 static int lockdep_open(struct inode *inode, struct file *file)
104 {
105 return seq_open(file, &lockdep_ops);
106 }
107
108 static const struct file_operations proc_lockdep_operations = {
109 .open = lockdep_open,
110 .read = seq_read,
111 .llseek = seq_lseek,
112 .release = seq_release,
113 };
114
115 #ifdef CONFIG_PROVE_LOCKING
116 static void *lc_start(struct seq_file *m, loff_t *pos)
117 {
118 if (*pos == 0)
119 return SEQ_START_TOKEN;
120
121 if (*pos - 1 < nr_lock_chains)
122 return lock_chains + (*pos - 1);
123
124 return NULL;
125 }
126
127 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
128 {
129 (*pos)++;
130 return lc_start(m, pos);
131 }
132
133 static void lc_stop(struct seq_file *m, void *v)
134 {
135 }
136
137 static int lc_show(struct seq_file *m, void *v)
138 {
139 struct lock_chain *chain = v;
140 struct lock_class *class;
141 int i;
142
143 if (v == SEQ_START_TOKEN) {
144 seq_printf(m, "all lock chains:\n");
145 return 0;
146 }
147
148 seq_printf(m, "irq_context: %d\n", chain->irq_context);
149
150 for (i = 0; i < chain->depth; i++) {
151 class = lock_chain_get_class(chain, i);
152 if (!class->key)
153 continue;
154
155 seq_printf(m, "[%p] ", class->key);
156 print_name(m, class);
157 seq_puts(m, "\n");
158 }
159 seq_puts(m, "\n");
160
161 return 0;
162 }
163
164 static const struct seq_operations lockdep_chains_ops = {
165 .start = lc_start,
166 .next = lc_next,
167 .stop = lc_stop,
168 .show = lc_show,
169 };
170
171 static int lockdep_chains_open(struct inode *inode, struct file *file)
172 {
173 return seq_open(file, &lockdep_chains_ops);
174 }
175
176 static const struct file_operations proc_lockdep_chains_operations = {
177 .open = lockdep_chains_open,
178 .read = seq_read,
179 .llseek = seq_lseek,
180 .release = seq_release,
181 };
182 #endif /* CONFIG_PROVE_LOCKING */
183
184 static void lockdep_stats_debug_show(struct seq_file *m)
185 {
186 #ifdef CONFIG_DEBUG_LOCKDEP
187 unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
188 hi2 = debug_atomic_read(&hardirqs_off_events),
189 hr1 = debug_atomic_read(&redundant_hardirqs_on),
190 hr2 = debug_atomic_read(&redundant_hardirqs_off),
191 si1 = debug_atomic_read(&softirqs_on_events),
192 si2 = debug_atomic_read(&softirqs_off_events),
193 sr1 = debug_atomic_read(&redundant_softirqs_on),
194 sr2 = debug_atomic_read(&redundant_softirqs_off);
195
196 seq_printf(m, " chain lookup misses: %11u\n",
197 debug_atomic_read(&chain_lookup_misses));
198 seq_printf(m, " chain lookup hits: %11u\n",
199 debug_atomic_read(&chain_lookup_hits));
200 seq_printf(m, " cyclic checks: %11u\n",
201 debug_atomic_read(&nr_cyclic_checks));
202 seq_printf(m, " find-mask forwards checks: %11u\n",
203 debug_atomic_read(&nr_find_usage_forwards_checks));
204 seq_printf(m, " find-mask backwards checks: %11u\n",
205 debug_atomic_read(&nr_find_usage_backwards_checks));
206
207 seq_printf(m, " hardirq on events: %11u\n", hi1);
208 seq_printf(m, " hardirq off events: %11u\n", hi2);
209 seq_printf(m, " redundant hardirq ons: %11u\n", hr1);
210 seq_printf(m, " redundant hardirq offs: %11u\n", hr2);
211 seq_printf(m, " softirq on events: %11u\n", si1);
212 seq_printf(m, " softirq off events: %11u\n", si2);
213 seq_printf(m, " redundant softirq ons: %11u\n", sr1);
214 seq_printf(m, " redundant softirq offs: %11u\n", sr2);
215 #endif
216 }
217
218 static int lockdep_stats_show(struct seq_file *m, void *v)
219 {
220 struct lock_class *class;
221 unsigned long nr_unused = 0, nr_uncategorized = 0,
222 nr_irq_safe = 0, nr_irq_unsafe = 0,
223 nr_softirq_safe = 0, nr_softirq_unsafe = 0,
224 nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
225 nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
226 nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
227 nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
228 sum_forward_deps = 0, factor = 0;
229
230 list_for_each_entry(class, &all_lock_classes, lock_entry) {
231
232 if (class->usage_mask == 0)
233 nr_unused++;
234 if (class->usage_mask == LOCKF_USED)
235 nr_uncategorized++;
236 if (class->usage_mask & LOCKF_USED_IN_IRQ)
237 nr_irq_safe++;
238 if (class->usage_mask & LOCKF_ENABLED_IRQ)
239 nr_irq_unsafe++;
240 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
241 nr_softirq_safe++;
242 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
243 nr_softirq_unsafe++;
244 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
245 nr_hardirq_safe++;
246 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
247 nr_hardirq_unsafe++;
248 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
249 nr_irq_read_safe++;
250 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
251 nr_irq_read_unsafe++;
252 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
253 nr_softirq_read_safe++;
254 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
255 nr_softirq_read_unsafe++;
256 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
257 nr_hardirq_read_safe++;
258 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
259 nr_hardirq_read_unsafe++;
260
261 #ifdef CONFIG_PROVE_LOCKING
262 sum_forward_deps += lockdep_count_forward_deps(class);
263 #endif
264 }
265 #ifdef CONFIG_DEBUG_LOCKDEP
266 DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
267 #endif
268 seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
269 nr_lock_classes, MAX_LOCKDEP_KEYS);
270 seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
271 nr_list_entries, MAX_LOCKDEP_ENTRIES);
272 seq_printf(m, " indirect dependencies: %11lu\n",
273 sum_forward_deps);
274
275 /*
276 * Total number of dependencies:
277 *
278 * All irq-safe locks may nest inside irq-unsafe locks,
279 * plus all the other known dependencies:
280 */
281 seq_printf(m, " all direct dependencies: %11lu\n",
282 nr_irq_unsafe * nr_irq_safe +
283 nr_hardirq_unsafe * nr_hardirq_safe +
284 nr_list_entries);
285
286 /*
287 * Estimated factor between direct and indirect
288 * dependencies:
289 */
290 if (nr_list_entries)
291 factor = sum_forward_deps / nr_list_entries;
292
293 #ifdef CONFIG_PROVE_LOCKING
294 seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
295 nr_lock_chains, MAX_LOCKDEP_CHAINS);
296 seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n",
297 nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
298 #endif
299
300 #ifdef CONFIG_TRACE_IRQFLAGS
301 seq_printf(m, " in-hardirq chains: %11u\n",
302 nr_hardirq_chains);
303 seq_printf(m, " in-softirq chains: %11u\n",
304 nr_softirq_chains);
305 #endif
306 seq_printf(m, " in-process chains: %11u\n",
307 nr_process_chains);
308 seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
309 nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
310 seq_printf(m, " combined max dependencies: %11u\n",
311 (nr_hardirq_chains + 1) *
312 (nr_softirq_chains + 1) *
313 (nr_process_chains + 1)
314 );
315 seq_printf(m, " hardirq-safe locks: %11lu\n",
316 nr_hardirq_safe);
317 seq_printf(m, " hardirq-unsafe locks: %11lu\n",
318 nr_hardirq_unsafe);
319 seq_printf(m, " softirq-safe locks: %11lu\n",
320 nr_softirq_safe);
321 seq_printf(m, " softirq-unsafe locks: %11lu\n",
322 nr_softirq_unsafe);
323 seq_printf(m, " irq-safe locks: %11lu\n",
324 nr_irq_safe);
325 seq_printf(m, " irq-unsafe locks: %11lu\n",
326 nr_irq_unsafe);
327
328 seq_printf(m, " hardirq-read-safe locks: %11lu\n",
329 nr_hardirq_read_safe);
330 seq_printf(m, " hardirq-read-unsafe locks: %11lu\n",
331 nr_hardirq_read_unsafe);
332 seq_printf(m, " softirq-read-safe locks: %11lu\n",
333 nr_softirq_read_safe);
334 seq_printf(m, " softirq-read-unsafe locks: %11lu\n",
335 nr_softirq_read_unsafe);
336 seq_printf(m, " irq-read-safe locks: %11lu\n",
337 nr_irq_read_safe);
338 seq_printf(m, " irq-read-unsafe locks: %11lu\n",
339 nr_irq_read_unsafe);
340
341 seq_printf(m, " uncategorized locks: %11lu\n",
342 nr_uncategorized);
343 seq_printf(m, " unused locks: %11lu\n",
344 nr_unused);
345 seq_printf(m, " max locking depth: %11u\n",
346 max_lockdep_depth);
347 #ifdef CONFIG_PROVE_LOCKING
348 seq_printf(m, " max bfs queue depth: %11u\n",
349 max_bfs_queue_depth);
350 #endif
351 lockdep_stats_debug_show(m);
352 seq_printf(m, " debug_locks: %11u\n",
353 debug_locks);
354
355 return 0;
356 }
357
358 static int lockdep_stats_open(struct inode *inode, struct file *file)
359 {
360 return single_open(file, lockdep_stats_show, NULL);
361 }
362
363 static const struct file_operations proc_lockdep_stats_operations = {
364 .open = lockdep_stats_open,
365 .read = seq_read,
366 .llseek = seq_lseek,
367 .release = single_release,
368 };
369
370 #ifdef CONFIG_LOCK_STAT
371
372 struct lock_stat_data {
373 struct lock_class *class;
374 struct lock_class_stats stats;
375 };
376
377 struct lock_stat_seq {
378 struct lock_stat_data *iter_end;
379 struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
380 };
381
382 /*
383 * sort on absolute number of contentions
384 */
385 static int lock_stat_cmp(const void *l, const void *r)
386 {
387 const struct lock_stat_data *dl = l, *dr = r;
388 unsigned long nl, nr;
389
390 nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
391 nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
392
393 return nr - nl;
394 }
395
396 static void seq_line(struct seq_file *m, char c, int offset, int length)
397 {
398 int i;
399
400 for (i = 0; i < offset; i++)
401 seq_puts(m, " ");
402 for (i = 0; i < length; i++)
403 seq_printf(m, "%c", c);
404 seq_puts(m, "\n");
405 }
406
407 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
408 {
409 s64 div;
410 s32 rem;
411
412 nr += 5; /* for display rounding */
413 div = div_s64_rem(nr, 1000, &rem);
414 snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
415 }
416
417 static void seq_time(struct seq_file *m, s64 time)
418 {
419 char num[15];
420
421 snprint_time(num, sizeof(num), time);
422 seq_printf(m, " %14s", num);
423 }
424
425 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
426 {
427 seq_printf(m, "%14lu", lt->nr);
428 seq_time(m, lt->min);
429 seq_time(m, lt->max);
430 seq_time(m, lt->total);
431 }
432
433 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
434 {
435 char name[39];
436 struct lock_class *class;
437 struct lock_class_stats *stats;
438 int i, namelen;
439
440 class = data->class;
441 stats = &data->stats;
442
443 namelen = 38;
444 if (class->name_version > 1)
445 namelen -= 2; /* XXX truncates versions > 9 */
446 if (class->subclass)
447 namelen -= 2;
448
449 if (!class->name) {
450 char str[KSYM_NAME_LEN];
451 const char *key_name;
452
453 key_name = __get_key_name(class->key, str);
454 snprintf(name, namelen, "%s", key_name);
455 } else {
456 snprintf(name, namelen, "%s", class->name);
457 }
458 namelen = strlen(name);
459 if (class->name_version > 1) {
460 snprintf(name+namelen, 3, "#%d", class->name_version);
461 namelen += 2;
462 }
463 if (class->subclass) {
464 snprintf(name+namelen, 3, "/%d", class->subclass);
465 namelen += 2;
466 }
467
468 if (stats->write_holdtime.nr) {
469 if (stats->read_holdtime.nr)
470 seq_printf(m, "%38s-W:", name);
471 else
472 seq_printf(m, "%40s:", name);
473
474 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
475 seq_lock_time(m, &stats->write_waittime);
476 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
477 seq_lock_time(m, &stats->write_holdtime);
478 seq_puts(m, "\n");
479 }
480
481 if (stats->read_holdtime.nr) {
482 seq_printf(m, "%38s-R:", name);
483 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
484 seq_lock_time(m, &stats->read_waittime);
485 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
486 seq_lock_time(m, &stats->read_holdtime);
487 seq_puts(m, "\n");
488 }
489
490 if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
491 return;
492
493 if (stats->read_holdtime.nr)
494 namelen += 2;
495
496 for (i = 0; i < LOCKSTAT_POINTS; i++) {
497 char sym[KSYM_SYMBOL_LEN];
498 char ip[32];
499
500 if (class->contention_point[i] == 0)
501 break;
502
503 if (!i)
504 seq_line(m, '-', 40-namelen, namelen);
505
506 sprint_symbol(sym, class->contention_point[i]);
507 snprintf(ip, sizeof(ip), "[<%p>]",
508 (void *)class->contention_point[i]);
509 seq_printf(m, "%40s %14lu %29s %s\n", name,
510 stats->contention_point[i],
511 ip, sym);
512 }
513 for (i = 0; i < LOCKSTAT_POINTS; i++) {
514 char sym[KSYM_SYMBOL_LEN];
515 char ip[32];
516
517 if (class->contending_point[i] == 0)
518 break;
519
520 if (!i)
521 seq_line(m, '-', 40-namelen, namelen);
522
523 sprint_symbol(sym, class->contending_point[i]);
524 snprintf(ip, sizeof(ip), "[<%p>]",
525 (void *)class->contending_point[i]);
526 seq_printf(m, "%40s %14lu %29s %s\n", name,
527 stats->contending_point[i],
528 ip, sym);
529 }
530 if (i) {
531 seq_puts(m, "\n");
532 seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
533 seq_puts(m, "\n");
534 }
535 }
536
537 static void seq_header(struct seq_file *m)
538 {
539 seq_printf(m, "lock_stat version 0.3\n");
540
541 if (unlikely(!debug_locks))
542 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
543
544 seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
545 seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
546 "%14s %14s\n",
547 "class name",
548 "con-bounces",
549 "contentions",
550 "waittime-min",
551 "waittime-max",
552 "waittime-total",
553 "acq-bounces",
554 "acquisitions",
555 "holdtime-min",
556 "holdtime-max",
557 "holdtime-total");
558 seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
559 seq_printf(m, "\n");
560 }
561
562 static void *ls_start(struct seq_file *m, loff_t *pos)
563 {
564 struct lock_stat_seq *data = m->private;
565 struct lock_stat_data *iter;
566
567 if (*pos == 0)
568 return SEQ_START_TOKEN;
569
570 iter = data->stats + (*pos - 1);
571 if (iter >= data->iter_end)
572 iter = NULL;
573
574 return iter;
575 }
576
577 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
578 {
579 (*pos)++;
580 return ls_start(m, pos);
581 }
582
583 static void ls_stop(struct seq_file *m, void *v)
584 {
585 }
586
587 static int ls_show(struct seq_file *m, void *v)
588 {
589 if (v == SEQ_START_TOKEN)
590 seq_header(m);
591 else
592 seq_stats(m, v);
593
594 return 0;
595 }
596
597 static const struct seq_operations lockstat_ops = {
598 .start = ls_start,
599 .next = ls_next,
600 .stop = ls_stop,
601 .show = ls_show,
602 };
603
604 static int lock_stat_open(struct inode *inode, struct file *file)
605 {
606 int res;
607 struct lock_class *class;
608 struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
609
610 if (!data)
611 return -ENOMEM;
612
613 res = seq_open(file, &lockstat_ops);
614 if (!res) {
615 struct lock_stat_data *iter = data->stats;
616 struct seq_file *m = file->private_data;
617
618 list_for_each_entry(class, &all_lock_classes, lock_entry) {
619 iter->class = class;
620 iter->stats = lock_stats(class);
621 iter++;
622 }
623 data->iter_end = iter;
624
625 sort(data->stats, data->iter_end - data->stats,
626 sizeof(struct lock_stat_data),
627 lock_stat_cmp, NULL);
628
629 m->private = data;
630 } else
631 vfree(data);
632
633 return res;
634 }
635
636 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
637 size_t count, loff_t *ppos)
638 {
639 struct lock_class *class;
640 char c;
641
642 if (count) {
643 if (get_user(c, buf))
644 return -EFAULT;
645
646 if (c != '0')
647 return count;
648
649 list_for_each_entry(class, &all_lock_classes, lock_entry)
650 clear_lock_stats(class);
651 }
652 return count;
653 }
654
655 static int lock_stat_release(struct inode *inode, struct file *file)
656 {
657 struct seq_file *seq = file->private_data;
658
659 vfree(seq->private);
660 return seq_release(inode, file);
661 }
662
663 static const struct file_operations proc_lock_stat_operations = {
664 .open = lock_stat_open,
665 .write = lock_stat_write,
666 .read = seq_read,
667 .llseek = seq_lseek,
668 .release = lock_stat_release,
669 };
670 #endif /* CONFIG_LOCK_STAT */
671
672 static int __init lockdep_proc_init(void)
673 {
674 proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
675 #ifdef CONFIG_PROVE_LOCKING
676 proc_create("lockdep_chains", S_IRUSR, NULL,
677 &proc_lockdep_chains_operations);
678 #endif
679 proc_create("lockdep_stats", S_IRUSR, NULL,
680 &proc_lockdep_stats_operations);
681
682 #ifdef CONFIG_LOCK_STAT
683 proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
684 &proc_lock_stat_operations);
685 #endif
686
687 return 0;
688 }
689
690 __initcall(lockdep_proc_init);
691
linux 2.6 git repository for openrd