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
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
|
/* Copyright (c) 2000, 2014, Oracle and/or its affiliates.
Copyright (c) 2009, 2017, MariaDB Corporation.
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, Fifth Floor, Boston, MA 02110-1301, USA */
/* Defines to make different thread packages compatible */
#ifndef _my_pthread_h
#define _my_pthread_h
#include "my_global.h" /* myf */
#ifndef ETIME
#define ETIME ETIMEDOUT /* For FreeBSD */
#endif
#ifdef __cplusplus
#define EXTERNC extern "C"
extern "C" {
#else
#define EXTERNC
#endif /* __cplusplus */
#if defined(__WIN__)
typedef CRITICAL_SECTION pthread_mutex_t;
typedef DWORD pthread_t;
typedef struct thread_attr {
DWORD dwStackSize ;
DWORD dwCreatingFlag ;
} pthread_attr_t ;
typedef struct { int dummy; } pthread_condattr_t;
/* Implementation of posix conditions */
typedef struct st_pthread_link {
DWORD thread_id;
struct st_pthread_link *next;
} pthread_link;
/**
Implementation of Windows condition variables.
We use native conditions on Vista and later, and fallback to own
implementation on earlier OS version.
*/
typedef CONDITION_VARIABLE pthread_cond_t;
typedef int pthread_mutexattr_t;
#define pthread_self() GetCurrentThreadId()
#define pthread_handler_t EXTERNC void * __cdecl
typedef void * (__cdecl *pthread_handler)(void *);
typedef INIT_ONCE my_pthread_once_t;
#define MY_PTHREAD_ONCE_INIT INIT_ONCE_STATIC_INIT;
#if !STRUCT_TIMESPEC_HAS_TV_SEC || !STRUCT_TIMESPEC_HAS_TV_NSEC
struct timespec {
time_t tv_sec;
long tv_nsec;
};
#endif
int win_pthread_mutex_trylock(pthread_mutex_t *mutex);
int pthread_create(pthread_t *, const pthread_attr_t *, pthread_handler, void *);
int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr);
int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex);
int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
const struct timespec *abstime);
int pthread_cond_signal(pthread_cond_t *cond);
int pthread_cond_broadcast(pthread_cond_t *cond);
int pthread_cond_destroy(pthread_cond_t *cond);
int pthread_attr_init(pthread_attr_t *connect_att);
int pthread_attr_setstacksize(pthread_attr_t *connect_att,DWORD stack);
int pthread_attr_destroy(pthread_attr_t *connect_att);
int my_pthread_once(my_pthread_once_t *once_control,void (*init_routine)(void));
static inline struct tm *localtime_r(const time_t *timep, struct tm *tmp)
{
localtime_s(tmp, timep);
return tmp;
}
static inline struct tm *gmtime_r(const time_t *clock, struct tm *res)
{
gmtime_s(res, clock);
return res;
}
void pthread_exit(void *a);
int pthread_join(pthread_t thread, void **value_ptr);
int pthread_cancel(pthread_t thread);
#ifndef ETIMEDOUT
#define ETIMEDOUT 145 /* Win32 doesn't have this */
#endif
#define getpid() GetCurrentThreadId()
#define HAVE_LOCALTIME_R 1
#define _REENTRANT 1
#define HAVE_PTHREAD_ATTR_SETSTACKSIZE 1
#undef SAFE_MUTEX /* This will cause conflicts */
#define pthread_key(T,V) DWORD V
#define pthread_key_create(A,B) ((*A=TlsAlloc())==0xFFFFFFFF)
#define pthread_key_delete(A) TlsFree(A)
#define my_pthread_setspecific_ptr(T,V) (!TlsSetValue((T),(V)))
#define pthread_setspecific(A,B) (!TlsSetValue((A),(B)))
#define pthread_getspecific(A) (TlsGetValue(A))
#define my_pthread_getspecific(T,A) ((T) TlsGetValue(A))
#define my_pthread_getspecific_ptr(T,V) ((T) TlsGetValue(V))
#define pthread_equal(A,B) ((A) == (B))
#define pthread_mutex_init(A,B) (InitializeCriticalSection(A),0)
#define pthread_mutex_lock(A) (EnterCriticalSection(A),0)
#define pthread_mutex_trylock(A) win_pthread_mutex_trylock((A))
#define pthread_mutex_unlock(A) (LeaveCriticalSection(A), 0)
#define pthread_mutex_destroy(A) (DeleteCriticalSection(A), 0)
#define pthread_kill(A,B) pthread_dummy((A) ? 0 : ESRCH)
/* Dummy defines for easier code */
#define pthread_attr_setdetachstate(A,B) pthread_dummy(0)
#define pthread_attr_setscope(A,B)
#define pthread_detach_this_thread()
#define pthread_condattr_init(A)
#define pthread_condattr_destroy(A)
#define pthread_yield() SwitchToThread()
#define my_sigset(A,B) signal(A,B)
#else /* Normal threads */
#ifdef HAVE_rts_threads
#define sigwait org_sigwait
#include <signal.h>
#undef sigwait
#endif
#include <pthread.h>
#ifndef _REENTRANT
#define _REENTRANT
#endif
#ifdef HAVE_THR_SETCONCURRENCY
#include <thread.h> /* Probably solaris */
#endif
#ifdef HAVE_SCHED_H
#include <sched.h>
#endif
#ifdef HAVE_SYNCH_H
#include <synch.h>
#endif
#define pthread_key(T,V) pthread_key_t V
#define my_pthread_getspecific_ptr(T,V) my_pthread_getspecific(T,(V))
#define my_pthread_setspecific_ptr(T,V) pthread_setspecific(T,(void*) (V))
#define pthread_detach_this_thread() { pthread_t tmp=pthread_self() ; pthread_detach(tmp); }
#define pthread_handler_t EXTERNC void *
typedef void *(* pthread_handler)(void *);
#define my_pthread_once_t pthread_once_t
#if defined(PTHREAD_ONCE_INITIALIZER)
#define MY_PTHREAD_ONCE_INIT PTHREAD_ONCE_INITIALIZER
#else
#define MY_PTHREAD_ONCE_INIT PTHREAD_ONCE_INIT
#endif
#define my_pthread_once(C,F) pthread_once(C,F)
/* Test first for RTS or FSU threads */
#if defined(PTHREAD_SCOPE_GLOBAL) && !defined(PTHREAD_SCOPE_SYSTEM)
#define HAVE_rts_threads
extern int my_pthread_create_detached;
#define pthread_sigmask(A,B,C) sigprocmask((A),(B),(C))
#define PTHREAD_CREATE_DETACHED &my_pthread_create_detached
#define PTHREAD_SCOPE_SYSTEM PTHREAD_SCOPE_GLOBAL
#define PTHREAD_SCOPE_PROCESS PTHREAD_SCOPE_LOCAL
#define USE_ALARM_THREAD
#endif /* defined(PTHREAD_SCOPE_GLOBAL) && !defined(PTHREAD_SCOPE_SYSTEM) */
#if defined(_BSDI_VERSION) && _BSDI_VERSION < 199910
int sigwait(sigset_t *set, int *sig);
#endif
#define my_sigwait(A,B) sigwait((A),(B))
#if defined(HAVE_SIGTHREADMASK) && !defined(HAVE_PTHREAD_SIGMASK)
#define pthread_sigmask(A,B,C) sigthreadmask((A),(B),(C))
#endif
#if !defined(HAVE_SIGWAIT) && !defined(HAVE_rts_threads) && !defined(sigwait) && !defined(alpha_linux_port) && !defined(_AIX)
int sigwait(sigset_t *setp, int *sigp); /* Use our implemention */
#endif
/*
We define my_sigset() and use that instead of the system sigset() so that
we can favor an implementation based on sigaction(). On some systems, such
as Mac OS X, sigset() results in flags such as SA_RESTART being set, and
we want to make sure that no such flags are set.
*/
#if defined(HAVE_SIGACTION) && !defined(my_sigset)
#define my_sigset(A,B) do { struct sigaction l_s; sigset_t l_set; \
DBUG_ASSERT((A) != 0); \
sigemptyset(&l_set); \
l_s.sa_handler = (B); \
l_s.sa_mask = l_set; \
l_s.sa_flags = 0; \
sigaction((A), &l_s, NULL); \
} while (0)
#elif defined(HAVE_SIGSET) && !defined(my_sigset)
#define my_sigset(A,B) sigset((A),(B))
#elif !defined(my_sigset)
#define my_sigset(A,B) signal((A),(B))
#endif
#if !defined(HAVE_PTHREAD_ATTR_SETSCOPE)
#define pthread_attr_setscope(A,B)
#undef HAVE_GETHOSTBYADDR_R /* No definition */
#endif
#define my_pthread_getspecific(A,B) ((A) pthread_getspecific(B))
#ifndef HAVE_LOCALTIME_R
struct tm *localtime_r(const time_t *clock, struct tm *res);
#endif
#ifndef HAVE_GMTIME_R
struct tm *gmtime_r(const time_t *clock, struct tm *res);
#endif
#ifdef HAVE_PTHREAD_CONDATTR_CREATE
/* DCE threads on HPUX 10.20 */
#define pthread_condattr_init pthread_condattr_create
#define pthread_condattr_destroy pthread_condattr_delete
#endif
/* FSU THREADS */
#if !defined(HAVE_PTHREAD_KEY_DELETE) && !defined(pthread_key_delete)
#define pthread_key_delete(A) pthread_dummy(0)
#endif
#if defined(HAVE_PTHREAD_ATTR_CREATE) && !defined(HAVE_SIGWAIT)
/* This is set on AIX_3_2 and Siemens unix (and DEC OSF/1 3.2 too) */
#define pthread_key_create(A,B) \
pthread_keycreate(A,(B) ?\
(pthread_destructor_t) (B) :\
(pthread_destructor_t) pthread_dummy)
#define pthread_attr_init(A) pthread_attr_create(A)
#define pthread_attr_destroy(A) pthread_attr_delete(A)
#define pthread_attr_setdetachstate(A,B) pthread_dummy(0)
#define pthread_create(A,B,C,D) pthread_create((A),*(B),(C),(D))
#ifndef pthread_sigmask
#define pthread_sigmask(A,B,C) sigprocmask((A),(B),(C))
#endif
#define pthread_kill(A,B) pthread_dummy((A) ? 0 : ESRCH)
#undef pthread_detach_this_thread
#define pthread_detach_this_thread() { pthread_t tmp=pthread_self() ; pthread_detach(&tmp); }
#else /* HAVE_PTHREAD_ATTR_CREATE && !HAVE_SIGWAIT */
#define HAVE_PTHREAD_KILL 1
#endif
#endif /* defined(__WIN__) */
#if defined(HPUX10) && !defined(DONT_REMAP_PTHREAD_FUNCTIONS)
#undef pthread_cond_timedwait
#define pthread_cond_timedwait(a,b,c) my_pthread_cond_timedwait((a),(b),(c))
int my_pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
struct timespec *abstime);
#endif
#if defined(HPUX10)
#define pthread_attr_getstacksize(A,B) my_pthread_attr_getstacksize(A,B)
void my_pthread_attr_getstacksize(pthread_attr_t *attrib, size_t *size);
#endif
#if defined(HAVE_POSIX1003_4a_MUTEX) && !defined(DONT_REMAP_PTHREAD_FUNCTIONS)
#undef pthread_mutex_trylock
#define pthread_mutex_trylock(a) my_pthread_mutex_trylock((a))
int my_pthread_mutex_trylock(pthread_mutex_t *mutex);
#endif
#if !defined(HAVE_PTHREAD_YIELD_ZERO_ARG)
/* no pthread_yield() available */
#ifdef HAVE_SCHED_YIELD
#define pthread_yield() sched_yield()
#elif defined(HAVE_PTHREAD_YIELD_NP) /* can be Mac OS X */
#define pthread_yield() pthread_yield_np()
#elif defined(HAVE_THR_YIELD)
#define pthread_yield() thr_yield()
#endif
#endif
/*
The defines set_timespec and set_timespec_nsec should be used
for calculating an absolute time at which
pthread_cond_timedwait should timeout
*/
#define set_timespec(ABSTIME,SEC) set_timespec_nsec((ABSTIME),(SEC)*1000000000ULL)
#ifndef set_timespec_nsec
#define set_timespec_nsec(ABSTIME,NSEC) \
set_timespec_time_nsec((ABSTIME), my_hrtime().val*1000 + (NSEC))
#endif /* !set_timespec_nsec */
/* adapt for two different flavors of struct timespec */
#ifdef HAVE_TIMESPEC_TS_SEC
#define MY_tv_sec ts_sec
#define MY_tv_nsec ts_nsec
#else
#define MY_tv_sec tv_sec
#define MY_tv_nsec tv_nsec
#endif /* HAVE_TIMESPEC_TS_SEC */
/**
Compare two timespec structs.
@retval 1 If TS1 ends after TS2.
@retval 0 If TS1 is equal to TS2.
@retval -1 If TS1 ends before TS2.
*/
#ifndef cmp_timespec
#define cmp_timespec(TS1, TS2) \
((TS1.MY_tv_sec > TS2.MY_tv_sec || \
(TS1.MY_tv_sec == TS2.MY_tv_sec && TS1.MY_tv_nsec > TS2.MY_tv_nsec)) ? 1 : \
((TS1.MY_tv_sec < TS2.MY_tv_sec || \
(TS1.MY_tv_sec == TS2.MY_tv_sec && TS1.MY_tv_nsec < TS2.MY_tv_nsec)) ? -1 : 0))
#endif /* !cmp_timespec */
#ifndef set_timespec_time_nsec
#define set_timespec_time_nsec(ABSTIME,NSEC) do { \
ulonglong _now_= (NSEC); \
(ABSTIME).MY_tv_sec= (_now_ / 1000000000ULL); \
(ABSTIME).MY_tv_nsec= (_now_ % 1000000000ULL); \
} while(0)
#endif /* !set_timespec_time_nsec */
/* safe_mutex adds checking to mutex for easier debugging */
struct st_hash;
typedef struct st_safe_mutex_t
{
pthread_mutex_t global,mutex;
const char *file, *name;
uint line,count;
myf create_flags, active_flags;
ulong id;
pthread_t thread;
struct st_hash *locked_mutex, *used_mutex;
struct st_safe_mutex_t *prev, *next;
#ifdef SAFE_MUTEX_DETECT_DESTROY
struct st_safe_mutex_info_t *info; /* to track destroying of mutexes */
#endif
} safe_mutex_t;
typedef struct st_safe_mutex_deadlock_t
{
const char *file, *name;
safe_mutex_t *mutex;
uint line;
ulong count;
ulong id;
my_bool warning_only;
} safe_mutex_deadlock_t;
#ifdef SAFE_MUTEX_DETECT_DESTROY
/*
Used to track the destroying of mutexes. This needs to be a seperate
structure because the safe_mutex_t structure could be freed before
the mutexes are destroyed.
*/
typedef struct st_safe_mutex_info_t
{
struct st_safe_mutex_info_t *next;
struct st_safe_mutex_info_t *prev;
const char *init_file;
uint32 init_line;
} safe_mutex_info_t;
#endif /* SAFE_MUTEX_DETECT_DESTROY */
int safe_mutex_init(safe_mutex_t *mp, const pthread_mutexattr_t *attr,
const char *name, const char *file, uint line);
int safe_mutex_lock(safe_mutex_t *mp, myf my_flags, const char *file,
uint line);
int safe_mutex_unlock(safe_mutex_t *mp,const char *file, uint line);
int safe_mutex_destroy(safe_mutex_t *mp,const char *file, uint line);
int safe_cond_wait(pthread_cond_t *cond, safe_mutex_t *mp,const char *file,
uint line);
int safe_cond_timedwait(pthread_cond_t *cond, safe_mutex_t *mp,
const struct timespec *abstime,
const char *file, uint line);
void safe_mutex_global_init(void);
void safe_mutex_end(FILE *file);
void safe_mutex_free_deadlock_data(safe_mutex_t *mp);
/* Wrappers if safe mutex is actually used */
#define MYF_TRY_LOCK 1
#define MYF_NO_DEADLOCK_DETECTION 2
#ifdef SAFE_MUTEX
#define safe_mutex_assert_owner(mp) \
DBUG_ASSERT((mp)->count > 0 && \
pthread_equal(pthread_self(), (mp)->thread))
#define safe_mutex_assert_not_owner(mp) \
DBUG_ASSERT(! (mp)->count || \
! pthread_equal(pthread_self(), (mp)->thread))
#define safe_mutex_setflags(mp, F) do { (mp)->create_flags|= (F); } while (0)
#define my_cond_timedwait(A,B,C) safe_cond_timedwait((A),(B),(C),__FILE__,__LINE__)
#define my_cond_wait(A,B) safe_cond_wait((A), (B), __FILE__, __LINE__)
#else
#define safe_mutex_assert_owner(mp) do {} while (0)
#define safe_mutex_assert_not_owner(mp) do {} while (0)
#define safe_mutex_setflags(mp, F) do {} while (0)
#define my_cond_timedwait(A,B,C) pthread_cond_timedwait((A),(B),(C))
#define my_cond_wait(A,B) pthread_cond_wait((A), (B))
#endif /* !SAFE_MUTEX */
/* READ-WRITE thread locking */
#if defined(USE_MUTEX_INSTEAD_OF_RW_LOCKS)
/* use these defs for simple mutex locking */
#define rw_lock_t pthread_mutex_t
#define my_rwlock_init(A,B) pthread_mutex_init((A),(B))
#define rw_rdlock(A) pthread_mutex_lock((A))
#define rw_wrlock(A) pthread_mutex_lock((A))
#define rw_tryrdlock(A) pthread_mutex_trylock((A))
#define rw_trywrlock(A) pthread_mutex_trylock((A))
#define rw_unlock(A) pthread_mutex_unlock((A))
#define rwlock_destroy(A) pthread_mutex_destroy((A))
#elif defined(HAVE_PTHREAD_RWLOCK_RDLOCK)
#define rw_lock_t pthread_rwlock_t
#define my_rwlock_init(A,B) pthread_rwlock_init((A),(B))
#define rw_rdlock(A) pthread_rwlock_rdlock(A)
#define rw_wrlock(A) pthread_rwlock_wrlock(A)
#define rw_tryrdlock(A) pthread_rwlock_tryrdlock((A))
#define rw_trywrlock(A) pthread_rwlock_trywrlock((A))
#define rw_unlock(A) pthread_rwlock_unlock(A)
#define rwlock_destroy(A) pthread_rwlock_destroy(A)
#elif defined(HAVE_RWLOCK_INIT)
#ifdef HAVE_RWLOCK_T /* For example Solaris 2.6-> */
#define rw_lock_t rwlock_t
#endif
#define my_rwlock_init(A,B) rwlock_init((A),USYNC_THREAD,0)
#else
/* Use our own version of read/write locks */
#define NEED_MY_RW_LOCK 1
#define rw_lock_t my_rw_lock_t
#define my_rwlock_init(A,B) my_rw_init((A))
#define rw_rdlock(A) my_rw_rdlock((A))
#define rw_wrlock(A) my_rw_wrlock((A))
#define rw_tryrdlock(A) my_rw_tryrdlock((A))
#define rw_trywrlock(A) my_rw_trywrlock((A))
#define rw_unlock(A) my_rw_unlock((A))
#define rwlock_destroy(A) my_rw_destroy((A))
#define rw_lock_assert_write_owner(A) my_rw_lock_assert_write_owner((A))
#define rw_lock_assert_not_write_owner(A) my_rw_lock_assert_not_write_owner((A))
#endif /* USE_MUTEX_INSTEAD_OF_RW_LOCKS */
/**
Portable implementation of special type of read-write locks.
These locks have two properties which are unusual for rwlocks:
1) They "prefer readers" in the sense that they do not allow
situations in which rwlock is rd-locked and there is a
pending rd-lock which is blocked (e.g. due to pending
request for wr-lock).
This is a stronger guarantee than one which is provided for
PTHREAD_RWLOCK_PREFER_READER_NP rwlocks in Linux.
MDL subsystem deadlock detector relies on this property for
its correctness.
2) They are optimized for uncontended wr-lock/unlock case.
This is scenario in which they are most oftenly used
within MDL subsystem. Optimizing for it gives significant
performance improvements in some of tests involving many
connections.
Another important requirement imposed on this type of rwlock
by the MDL subsystem is that it should be OK to destroy rwlock
object which is in unlocked state even though some threads might
have not yet fully left unlock operation for it (of course there
is an external guarantee that no thread will try to lock rwlock
which is destroyed).
Putting it another way the unlock operation should not access
rwlock data after changing its state to unlocked.
TODO/FIXME: We should consider alleviating this requirement as
it blocks us from doing certain performance optimizations.
*/
typedef struct st_rw_pr_lock_t {
/**
Lock which protects the structure.
Also held for the duration of wr-lock.
*/
pthread_mutex_t lock;
/**
Condition variable which is used to wake-up
writers waiting for readers to go away.
*/
pthread_cond_t no_active_readers;
/** Number of active readers. */
uint active_readers;
/** Number of writers waiting for readers to go away. */
uint writers_waiting_readers;
/** Indicates whether there is an active writer. */
my_bool active_writer;
#ifdef SAFE_MUTEX
/** Thread holding wr-lock (for debug purposes only). */
pthread_t writer_thread;
#endif
} rw_pr_lock_t;
extern int rw_pr_init(rw_pr_lock_t *);
extern int rw_pr_rdlock(rw_pr_lock_t *);
extern int rw_pr_wrlock(rw_pr_lock_t *);
extern int rw_pr_unlock(rw_pr_lock_t *);
extern int rw_pr_destroy(rw_pr_lock_t *);
#ifdef SAFE_MUTEX
#define rw_pr_lock_assert_write_owner(A) \
DBUG_ASSERT((A)->active_writer && pthread_equal(pthread_self(), \
(A)->writer_thread))
#define rw_pr_lock_assert_not_write_owner(A) \
DBUG_ASSERT(! (A)->active_writer || ! pthread_equal(pthread_self(), \
(A)->writer_thread))
#else
#define rw_pr_lock_assert_write_owner(A)
#define rw_pr_lock_assert_not_write_owner(A)
#endif /* SAFE_MUTEX */
#ifdef NEED_MY_RW_LOCK
#ifdef _WIN32
/**
Implementation of Windows rwlock.
We use native (slim) rwlocks on Win7 and later, and fallback to portable
implementation on earlier Windows.
slim rwlock are also available on Vista/WS2008, but we do not use it
("trylock" APIs are missing on Vista)
*/
typedef union
{
/* Native rwlock (is_srwlock == TRUE) */
struct
{
SRWLOCK srwlock; /* native reader writer lock */
BOOL have_exclusive_srwlock; /* used for unlock */
};
/*
Portable implementation (is_srwlock == FALSE)
Fields are identical with Unix my_rw_lock_t fields.
*/
struct
{
pthread_mutex_t lock; /* lock for structure */
pthread_cond_t readers; /* waiting readers */
pthread_cond_t writers; /* waiting writers */
int state; /* -1:writer,0:free,>0:readers */
int waiters; /* number of waiting writers */
#ifdef SAFE_MUTEX
pthread_t write_thread;
#endif
};
} my_rw_lock_t;
#else /* _WIN32 */
/*
On systems which don't support native read/write locks we have
to use own implementation.
*/
typedef struct st_my_rw_lock_t {
pthread_mutex_t lock; /* lock for structure */
pthread_cond_t readers; /* waiting readers */
pthread_cond_t writers; /* waiting writers */
int state; /* -1:writer,0:free,>0:readers */
int waiters; /* number of waiting writers */
#ifdef SAFE_MUTEX
pthread_t write_thread;
#endif
} my_rw_lock_t;
#endif /*! _WIN32 */
extern int my_rw_init(my_rw_lock_t *);
extern int my_rw_destroy(my_rw_lock_t *);
extern int my_rw_rdlock(my_rw_lock_t *);
extern int my_rw_wrlock(my_rw_lock_t *);
extern int my_rw_unlock(my_rw_lock_t *);
extern int my_rw_tryrdlock(my_rw_lock_t *);
extern int my_rw_trywrlock(my_rw_lock_t *);
#ifdef SAFE_MUTEX
#define my_rw_lock_assert_write_owner(A) \
DBUG_ASSERT((A)->state == -1 && pthread_equal(pthread_self(), \
(A)->write_thread))
#define my_rw_lock_assert_not_write_owner(A) \
DBUG_ASSERT((A)->state >= 0 || ! pthread_equal(pthread_self(), \
(A)->write_thread))
#else
#define my_rw_lock_assert_write_owner(A)
#define my_rw_lock_assert_not_write_owner(A)
#endif
#endif /* NEED_MY_RW_LOCK */
#define GETHOSTBYADDR_BUFF_SIZE 2048
#ifndef HAVE_THR_SETCONCURRENCY
#define thr_setconcurrency(A) pthread_dummy(0)
#endif
#if !defined(HAVE_PTHREAD_ATTR_SETSTACKSIZE) && ! defined(pthread_attr_setstacksize)
#define pthread_attr_setstacksize(A,B) pthread_dummy(0)
#endif
/* Define mutex types, see my_thr_init.c */
#define MY_MUTEX_INIT_SLOW NULL
#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
extern pthread_mutexattr_t my_fast_mutexattr;
#define MY_MUTEX_INIT_FAST &my_fast_mutexattr
#else
#define MY_MUTEX_INIT_FAST NULL
#endif
#ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
extern pthread_mutexattr_t my_errorcheck_mutexattr;
#define MY_MUTEX_INIT_ERRCHK &my_errorcheck_mutexattr
#else
#define MY_MUTEX_INIT_ERRCHK NULL
#endif
#ifndef ESRCH
/* Define it to something */
#define ESRCH 1
#endif
typedef uint64 my_thread_id;
extern void my_threadattr_global_init(void);
extern my_bool my_thread_global_init(void);
extern void my_thread_global_reinit(void);
extern void my_thread_global_end(void);
extern my_bool my_thread_init(void);
extern void my_thread_end(void);
extern const char *my_thread_name(void);
extern my_thread_id my_thread_dbug_id(void);
extern int pthread_dummy(int);
extern void my_mutex_init(void);
extern void my_mutex_end(void);
/* All thread specific variables are in the following struct */
#define THREAD_NAME_SIZE 10
#ifndef DEFAULT_THREAD_STACK
/*
We need to have at least 256K stack to handle calls to myisamchk_init()
with the current number of keys and key parts.
*/
#define DEFAULT_THREAD_STACK (292*1024L)
#endif
#define MY_PTHREAD_LOCK_READ 0
#define MY_PTHREAD_LOCK_WRITE 1
#include <mysql/psi/mysql_thread.h>
#define INSTRUMENT_ME 0
struct st_my_thread_var
{
int thr_errno;
mysql_cond_t suspend;
mysql_mutex_t mutex;
mysql_mutex_t * volatile current_mutex;
mysql_cond_t * volatile current_cond;
pthread_t pthread_self;
my_thread_id id, dbug_id;
int volatile abort;
my_bool init;
struct st_my_thread_var *next,**prev;
void *keycache_link;
uint lock_type; /* used by conditional release the queue */
void *stack_ends_here;
safe_mutex_t *mutex_in_use;
#ifndef DBUG_OFF
void *dbug;
char name[THREAD_NAME_SIZE+1];
#endif
};
extern struct st_my_thread_var *_my_thread_var(void) __attribute__ ((const));
extern void **my_thread_var_dbug(void);
extern safe_mutex_t **my_thread_var_mutex_in_use(void);
extern uint my_thread_end_wait_time;
extern my_bool safe_mutex_deadlock_detector;
#define my_thread_var (_my_thread_var())
#define my_errno my_thread_var->thr_errno
/*
Keep track of shutdown,signal, and main threads so that my_end() will not
report errors with them
*/
/* Which kind of thread library is in use */
#define THD_LIB_OTHER 1
#define THD_LIB_NPTL 2
#define THD_LIB_LT 4
extern uint thd_lib_detected;
/*
thread_safe_xxx functions are for critical statistic or counters.
The implementation is guaranteed to be thread safe, on all platforms.
Note that the calling code should *not* assume the counter is protected
by the mutex given, as the implementation of these helpers may change
to use my_atomic operations instead.
*/
#ifndef thread_safe_increment
#ifdef _WIN32
#define thread_safe_increment(V,L) InterlockedIncrement((long*) &(V))
#define thread_safe_decrement(V,L) InterlockedDecrement((long*) &(V))
#else
#define thread_safe_increment(V,L) \
(mysql_mutex_lock((L)), (V)++, mysql_mutex_unlock((L)))
#define thread_safe_decrement(V,L) \
(mysql_mutex_lock((L)), (V)--, mysql_mutex_unlock((L)))
#endif
#endif
#ifndef thread_safe_add
#ifdef _WIN32
#define thread_safe_add(V,C,L) InterlockedExchangeAdd((long*) &(V),(C))
#define thread_safe_sub(V,C,L) InterlockedExchangeAdd((long*) &(V),-(long) (C))
#else
#define thread_safe_add(V,C,L) \
(mysql_mutex_lock((L)), (V)+=(C), mysql_mutex_unlock((L)))
#define thread_safe_sub(V,C,L) \
(mysql_mutex_lock((L)), (V)-=(C), mysql_mutex_unlock((L)))
#endif
#endif
/*
statistics_xxx functions are for non critical statistic,
maintained in global variables.
When compiling with SAFE_STATISTICS:
- race conditions can not occur.
- some locking occurs, which may cause performance degradation.
When compiling without SAFE_STATISTICS:
- race conditions can occur, making the result slightly inaccurate.
- the lock given is not honored.
*/
#ifdef SAFE_STATISTICS
#define statistic_increment(V,L) thread_safe_increment((V),(L))
#define statistic_decrement(V,L) thread_safe_decrement((V),(L))
#define statistic_add(V,C,L) thread_safe_add((V),(C),(L))
#define statistic_sub(V,C,L) thread_safe_sub((V),(C),(L))
#else
#define statistic_decrement(V,L) (V)--
#define statistic_increment(V,L) (V)++
#define statistic_add(V,C,L) (V)+=(C)
#define statistic_sub(V,C,L) (V)-=(C)
#endif /* SAFE_STATISTICS */
/*
No locking needed, the counter is owned by the thread
*/
#define status_var_increment(V) (V)++
#define status_var_decrement(V) (V)--
#define status_var_add(V,C) (V)+=(C)
#define status_var_sub(V,C) (V)-=(C)
#ifdef SAFE_MUTEX
#define mysql_mutex_record_order(A,B) \
do { \
mysql_mutex_lock(A); mysql_mutex_lock(B); \
mysql_mutex_unlock(B); mysql_mutex_unlock(A); \
} while(0)
#else
#define mysql_mutex_record_order(A,B) do { } while(0)
#endif
/* At least Windows and NetBSD do not have this definition */
#ifndef PTHREAD_STACK_MIN
#define PTHREAD_STACK_MIN 65536
#endif
#ifdef __cplusplus
}
#endif
#endif /* _my_ptread_h */
|