1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
|
/*****************************************************************************
Copyright (c) 2013, 2015, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2017, MariaDB Corporation. All Rights Reserved.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
*****************************************************************************/
/******************************************************************//**
@file include/ib0mutex.h
Policy based mutexes.
Created 2013-03-26 Sunny Bains.
***********************************************************************/
#ifndef UNIV_INNOCHECKSUM
#ifndef ib0mutex_h
#define ib0mutex_h
#include "ut0ut.h"
#include "ut0rnd.h"
#include "os0event.h"
#include "sync0arr.h"
/** OS mutex for tracking lock/unlock for debugging */
template <template <typename> class Policy>
struct OSTrackMutex {
typedef Policy<OSTrackMutex> MutexPolicy;
explicit OSTrackMutex(bool destroy_mutex_at_exit = true)
UNIV_NOTHROW
{
ut_d(m_freed = true);
ut_d(m_locked = false);
ut_d(m_destroy_at_exit = destroy_mutex_at_exit);
}
~OSTrackMutex() UNIV_NOTHROW
{
ut_ad(!m_destroy_at_exit || !m_locked);
}
/** Initialise the mutex. */
void init(latch_id_t, const char*, uint32_t) UNIV_NOTHROW
{
ut_ad(m_freed);
ut_ad(!m_locked);
m_mutex.init();
ut_d(m_freed = false);
}
/** Destroy the mutex */
void destroy() UNIV_NOTHROW
{
ut_ad(!m_locked);
ut_ad(!m_freed);
m_mutex.destroy();
ut_d(m_freed = true);
}
/** Release the mutex. */
void exit() UNIV_NOTHROW
{
ut_ad(m_locked);
ut_d(m_locked = false);
ut_ad(!m_freed);
m_mutex.exit();
}
/** Acquire the mutex. */
void enter(uint32_t, uint32_t, const char*, uint32_t)
UNIV_NOTHROW
{
ut_ad(!m_freed);
m_mutex.enter();
ut_ad(!m_locked);
ut_d(m_locked = true);
}
/** @return true if locking succeeded */
bool try_lock() UNIV_NOTHROW
{
ut_ad(!m_freed);
bool locked = m_mutex.try_lock();
if (locked) {
ut_ad(!m_locked);
ut_d(m_locked = locked);
}
return(locked);
}
/** @return non-const version of the policy */
MutexPolicy& policy()
UNIV_NOTHROW
{
return(m_policy);
}
/** @return the const version of the policy */
const MutexPolicy& policy() const
UNIV_NOTHROW
{
return(m_policy);
}
private:
#ifdef UNIV_DEBUG
/** true if the mutex has not be initialized */
bool m_freed;
/** true if the mutex has been locked. */
bool m_locked;
/** Do/Dont destroy mutex at exit */
bool m_destroy_at_exit;
#endif /* UNIV_DEBUG */
/** OS Mutex instance */
OSMutex m_mutex;
/** Policy data */
MutexPolicy m_policy;
};
#ifdef HAVE_IB_LINUX_FUTEX
#include <linux/futex.h>
#include <sys/syscall.h>
/** Mutex implementation that used the Linux futex. */
template <template <typename> class Policy>
struct TTASFutexMutex {
typedef Policy<TTASFutexMutex> MutexPolicy;
TTASFutexMutex() UNIV_NOTHROW
:
m_lock_word(MUTEX_STATE_UNLOCKED)
{
/* Check that lock_word is aligned. */
ut_ad(!((ulint) &m_lock_word % sizeof(ulint)));
}
~TTASFutexMutex()
{
ut_ad(m_lock_word.load(std::memory_order_relaxed)
== MUTEX_STATE_UNLOCKED);
}
/** Called when the mutex is "created". Note: Not from the constructor
but when the mutex is initialised. */
void init(latch_id_t, const char*, uint32_t) UNIV_NOTHROW
{
ut_ad(m_lock_word.load(std::memory_order_relaxed)
== MUTEX_STATE_UNLOCKED);
}
/** Destroy the mutex. */
void destroy() UNIV_NOTHROW
{
/* The destructor can be called at shutdown. */
ut_ad(m_lock_word.load(std::memory_order_relaxed)
== MUTEX_STATE_UNLOCKED);
}
/** Acquire the mutex.
@param[in] max_spins max number of spins
@param[in] max_delay max delay per spin */
void enter(uint32_t max_spins, uint32_t max_delay,
const char*, uint32_t) UNIV_NOTHROW
{
uint32_t n_spins, n_waits;
for (n_spins= 0; n_spins < max_spins; n_spins++) {
if (try_lock()) {
m_policy.add(n_spins, 0);
return;
}
ut_delay(max_delay);
}
for (n_waits= 0;; n_waits++) {
if (m_lock_word.exchange(MUTEX_STATE_WAITERS,
std::memory_order_acquire)
== MUTEX_STATE_UNLOCKED) {
break;
}
syscall(SYS_futex, &m_lock_word,
FUTEX_WAIT_PRIVATE, MUTEX_STATE_WAITERS,
0, 0, 0);
}
m_policy.add(n_spins, n_waits);
}
/** Release the mutex. */
void exit() UNIV_NOTHROW
{
if (m_lock_word.exchange(MUTEX_STATE_UNLOCKED,
std::memory_order_release)
== MUTEX_STATE_WAITERS) {
syscall(SYS_futex, &m_lock_word, FUTEX_WAKE_PRIVATE,
1, 0, 0, 0);
}
}
/** Try and lock the mutex.
@return true if successful */
bool try_lock() UNIV_NOTHROW
{
int32 oldval = MUTEX_STATE_UNLOCKED;
return m_lock_word.compare_exchange_strong(
oldval,
MUTEX_STATE_LOCKED,
std::memory_order_acquire,
std::memory_order_relaxed);
}
/** @return non-const version of the policy */
MutexPolicy& policy() UNIV_NOTHROW
{
return(m_policy);
}
/** @return const version of the policy */
const MutexPolicy& policy() const UNIV_NOTHROW
{
return(m_policy);
}
private:
/** Policy data */
MutexPolicy m_policy;
/** lock_word is the target of the atomic test-and-set instruction
when atomic operations are enabled. */
std::atomic<int32> m_lock_word;
};
#endif /* HAVE_IB_LINUX_FUTEX */
template <template <typename> class Policy>
struct TTASMutex {
typedef Policy<TTASMutex> MutexPolicy;
TTASMutex() UNIV_NOTHROW
:
m_lock_word(MUTEX_STATE_UNLOCKED)
{
/* Check that lock_word is aligned. */
ut_ad(!((ulint) &m_lock_word % sizeof(ulint)));
}
~TTASMutex()
{
ut_ad(m_lock_word.load(std::memory_order_relaxed)
== MUTEX_STATE_UNLOCKED);
}
/** Called when the mutex is "created". Note: Not from the constructor
but when the mutex is initialised. */
void init(latch_id_t) UNIV_NOTHROW
{
ut_ad(m_lock_word.load(std::memory_order_relaxed)
== MUTEX_STATE_UNLOCKED);
}
/** Destroy the mutex. */
void destroy() UNIV_NOTHROW
{
/* The destructor can be called at shutdown. */
ut_ad(m_lock_word.load(std::memory_order_relaxed)
== MUTEX_STATE_UNLOCKED);
}
/** Try and lock the mutex.
@return true on success */
bool try_lock() UNIV_NOTHROW
{
uint32_t oldval = MUTEX_STATE_UNLOCKED;
return m_lock_word.compare_exchange_strong(
oldval,
MUTEX_STATE_LOCKED,
std::memory_order_acquire,
std::memory_order_relaxed);
}
/** Release the mutex. */
void exit() UNIV_NOTHROW
{
ut_ad(m_lock_word.load(std::memory_order_relaxed)
== MUTEX_STATE_LOCKED);
m_lock_word.store(MUTEX_STATE_UNLOCKED,
std::memory_order_release);
}
/** Acquire the mutex.
@param max_spins max number of spins
@param max_delay max delay per spin */
void enter(uint32_t max_spins, uint32_t max_delay,
const char*, uint32_t) UNIV_NOTHROW
{
const uint32_t step = max_spins;
uint32_t n_spins = 0;
while (!try_lock()) {
ut_delay(max_delay);
if (++n_spins == max_spins) {
os_thread_yield();
max_spins+= step;
}
}
m_policy.add(n_spins, 0);
}
/** @return non-const version of the policy */
MutexPolicy& policy() UNIV_NOTHROW
{
return(m_policy);
}
/** @return const version of the policy */
const MutexPolicy& policy() const UNIV_NOTHROW
{
return(m_policy);
}
private:
// Disable copying
TTASMutex(const TTASMutex&);
TTASMutex& operator=(const TTASMutex&);
/** Policy data */
MutexPolicy m_policy;
/** mutex state */
std::atomic<uint32_t> m_lock_word;
};
template <template <typename> class Policy>
struct TTASEventMutex {
typedef Policy<TTASEventMutex> MutexPolicy;
TTASEventMutex()
UNIV_NOTHROW
:
m_lock_word(MUTEX_STATE_UNLOCKED),
m_event()
{
/* Check that lock_word is aligned. */
ut_ad(!((ulint) &m_lock_word % sizeof(ulint)));
}
~TTASEventMutex()
UNIV_NOTHROW
{
ut_ad(state() == MUTEX_STATE_UNLOCKED);
}
/** Called when the mutex is "created". Note: Not from the constructor
but when the mutex is initialised.
@param[in] id Mutex ID */
void init(latch_id_t id, const char*, uint32_t) UNIV_NOTHROW
{
ut_a(m_event == 0);
ut_ad(state() == MUTEX_STATE_UNLOCKED);
m_event = os_event_create(sync_latch_get_name(id));
}
/** This is the real desctructor. This mutex can be created in BSS and
its desctructor will be called on exit(). We can't call
os_event_destroy() at that stage. */
void destroy()
UNIV_NOTHROW
{
ut_ad(state() == MUTEX_STATE_UNLOCKED);
/* We have to free the event before InnoDB shuts down. */
os_event_destroy(m_event);
m_event = 0;
}
/** Try and lock the mutex. Note: POSIX returns 0 on success.
@return true on success */
bool try_lock()
UNIV_NOTHROW
{
uint32_t oldval = MUTEX_STATE_UNLOCKED;
return m_lock_word.compare_exchange_strong(
oldval,
MUTEX_STATE_LOCKED,
std::memory_order_acquire,
std::memory_order_relaxed);
}
/** Release the mutex. */
void exit()
UNIV_NOTHROW
{
if (m_lock_word.exchange(MUTEX_STATE_UNLOCKED,
std::memory_order_release)
== MUTEX_STATE_WAITERS) {
os_event_set(m_event);
sync_array_object_signalled();
}
}
/** Acquire the mutex.
@param[in] max_spins max number of spins
@param[in] max_delay max delay per spin
@param[in] filename from where called
@param[in] line within filename */
void enter(
uint32_t max_spins,
uint32_t max_delay,
const char* filename,
uint32_t line)
UNIV_NOTHROW
{
uint32_t n_spins = 0;
uint32_t n_waits = 0;
const uint32_t step = max_spins;
while (!try_lock()) {
if (n_spins++ == max_spins) {
max_spins += step;
n_waits++;
os_thread_yield();
sync_cell_t* cell;
sync_array_t *sync_arr = sync_array_get_and_reserve_cell(
this,
(m_policy.get_id() == LATCH_ID_BUF_BLOCK_MUTEX
|| m_policy.get_id() == LATCH_ID_BUF_POOL_ZIP)
? SYNC_BUF_BLOCK
: SYNC_MUTEX,
filename, line, &cell);
uint32_t oldval = MUTEX_STATE_LOCKED;
m_lock_word.compare_exchange_strong(
oldval,
MUTEX_STATE_WAITERS,
std::memory_order_relaxed,
std::memory_order_relaxed);
if (oldval == MUTEX_STATE_UNLOCKED) {
sync_array_free_cell(sync_arr, cell);
} else {
sync_array_wait_event(sync_arr, cell);
}
} else {
ut_delay(max_delay);
}
}
m_policy.add(n_spins, n_waits);
}
/** @return the lock state. */
int32 state() const
UNIV_NOTHROW
{
return m_lock_word.load(std::memory_order_relaxed);
}
/** The event that the mutex will wait in sync0arr.cc
@return even instance */
os_event_t event()
UNIV_NOTHROW
{
return(m_event);
}
/** @return non-const version of the policy */
MutexPolicy& policy()
UNIV_NOTHROW
{
return(m_policy);
}
/** @return const version of the policy */
const MutexPolicy& policy() const
UNIV_NOTHROW
{
return(m_policy);
}
private:
/** Disable copying */
TTASEventMutex(const TTASEventMutex&);
TTASEventMutex& operator=(const TTASEventMutex&);
/** mutex state */
std::atomic<uint32_t> m_lock_word;
/** Used by sync0arr.cc for the wait queue */
os_event_t m_event;
/** Policy data */
MutexPolicy m_policy;
};
/** Mutex interface for all policy mutexes. This class handles the interfacing
with the Performance Schema instrumentation. */
template <typename MutexImpl>
struct PolicyMutex
{
typedef typename MutexImpl::MutexPolicy Policy;
PolicyMutex() UNIV_NOTHROW : m_impl()
{
#ifdef UNIV_PFS_MUTEX
m_ptr = 0;
#endif /* UNIV_PFS_MUTEX */
}
~PolicyMutex() { }
/** @return non-const version of the policy */
Policy& policy() UNIV_NOTHROW
{
return(m_impl.policy());
}
/** @return const version of the policy */
const Policy& policy() const UNIV_NOTHROW
{
return(m_impl.policy());
}
/** Release the mutex. */
void exit() UNIV_NOTHROW
{
#ifdef UNIV_PFS_MUTEX
pfs_exit();
#endif /* UNIV_PFS_MUTEX */
ut_d(policy().context.release(m_impl));
m_impl.exit();
}
/** Acquire the mutex.
@param n_spins max number of spins
@param n_delay max delay per spin
@param name filename where locked
@param line line number where locked */
void enter(
uint32_t n_spins,
uint32_t n_delay,
const char* name,
uint32_t line) UNIV_NOTHROW
{
#ifdef UNIV_PFS_MUTEX
/* Note: locker is really an alias for state. That's why
it has to be in the same scope during pfs_end(). */
PSI_mutex_locker_state state;
PSI_mutex_locker* locker;
locker = pfs_begin_lock(&state, name, line);
#endif /* UNIV_PFS_MUTEX */
ut_d(policy().context.enter(m_impl, name, line));
m_impl.enter(n_spins, n_delay, name, line);
ut_d(policy().context.locked(m_impl, name, line));
#ifdef UNIV_PFS_MUTEX
pfs_end(locker, 0);
#endif /* UNIV_PFS_MUTEX */
}
/** Try and lock the mutex, return 0 on SUCCESS and 1 otherwise.
@param name filename where locked
@param line line number where locked */
int trylock(const char* name, uint32_t line) UNIV_NOTHROW
{
#ifdef UNIV_PFS_MUTEX
/* Note: locker is really an alias for state. That's why
it has to be in the same scope during pfs_end(). */
PSI_mutex_locker_state state;
PSI_mutex_locker* locker;
locker = pfs_begin_trylock(&state, name, line);
#endif /* UNIV_PFS_MUTEX */
/* There is a subtlety here, we check the mutex ordering
after locking here. This is only done to avoid add and
then remove if the trylock was unsuccesful. */
int ret = m_impl.try_lock() ? 0 : 1;
if (ret == 0) {
ut_d(policy().context.enter(m_impl, name, line));
ut_d(policy().context.locked(m_impl, name, line));
}
#ifdef UNIV_PFS_MUTEX
pfs_end(locker, 0);
#endif /* UNIV_PFS_MUTEX */
return(ret);
}
#ifdef UNIV_DEBUG
/** @return true if the thread owns the mutex. */
bool is_owned() const UNIV_NOTHROW
{
return(policy().context.is_owned());
}
#endif /* UNIV_DEBUG */
/**
Initialise the mutex.
@param[in] id Mutex ID
@param[in] filename file where created
@param[in] line line number in file where created */
void init(
latch_id_t id,
const char* filename,
uint32_t line)
UNIV_NOTHROW
{
#ifdef UNIV_PFS_MUTEX
pfs_add(sync_latch_get_pfs_key(id));
#endif /* UNIV_PFS_MUTEX */
m_impl.init(id, filename, line);
policy().init(m_impl, id, filename, line);
ut_d(policy().context.init(id));
}
/** Free resources (if any) */
void destroy() UNIV_NOTHROW
{
#ifdef UNIV_PFS_MUTEX
pfs_del();
#endif /* UNIV_PFS_MUTEX */
m_impl.destroy();
policy().destroy();
ut_d(policy().context.destroy());
}
/** Required for os_event_t */
operator sys_mutex_t*() UNIV_NOTHROW
{
return(m_impl.operator sys_mutex_t*());
}
#ifdef UNIV_PFS_MUTEX
/** Performance schema monitoring - register mutex with PFS.
Note: This is public only because we want to get around an issue
with registering a subset of buffer pool pages with PFS when
PFS_GROUP_BUFFER_SYNC is defined. Therefore this has to then
be called by external code (see buf0buf.cc).
@param key - Performance Schema key. */
void pfs_add(mysql_pfs_key_t key) UNIV_NOTHROW
{
ut_ad(m_ptr == 0);
m_ptr = PSI_MUTEX_CALL(init_mutex)(key, this);
}
private:
/** Performance schema monitoring.
@param state - PFS locker state
@param name - file name where locked
@param line - line number in file where locked */
PSI_mutex_locker* pfs_begin_lock(
PSI_mutex_locker_state* state,
const char* name,
uint32_t line) UNIV_NOTHROW
{
if (m_ptr != 0) {
return(PSI_MUTEX_CALL(start_mutex_wait)(
state, m_ptr,
PSI_MUTEX_LOCK, name, (uint) line));
}
return(0);
}
/** Performance schema monitoring.
@param state - PFS locker state
@param name - file name where locked
@param line - line number in file where locked */
PSI_mutex_locker* pfs_begin_trylock(
PSI_mutex_locker_state* state,
const char* name,
uint32_t line) UNIV_NOTHROW
{
if (m_ptr != 0) {
return(PSI_MUTEX_CALL(start_mutex_wait)(
state, m_ptr,
PSI_MUTEX_TRYLOCK, name, (uint) line));
}
return(0);
}
/** Performance schema monitoring
@param locker - PFS identifier
@param ret - 0 for success and 1 for failure */
void pfs_end(PSI_mutex_locker* locker, int ret) UNIV_NOTHROW
{
if (locker != 0) {
PSI_MUTEX_CALL(end_mutex_wait)(locker, ret);
}
}
/** Performance schema monitoring - register mutex release */
void pfs_exit()
{
if (m_ptr != 0) {
PSI_MUTEX_CALL(unlock_mutex)(m_ptr);
}
}
/** Performance schema monitoring - deregister */
void pfs_del()
{
if (m_ptr != 0) {
PSI_MUTEX_CALL(destroy_mutex)(m_ptr);
m_ptr = 0;
}
}
#endif /* UNIV_PFS_MUTEX */
private:
/** The mutex implementation */
MutexImpl m_impl;
#ifdef UNIV_PFS_MUTEX
/** The performance schema instrumentation hook. */
PSI_mutex* m_ptr;
#endif /* UNIV_PFS_MUTEX */
};
#endif /* ib0mutex_h */
#endif /* !UNIV_INNOCHECKSUM */
|