diff options
Diffstat (limited to 'mysys')
| -rw-r--r-- | mysys/my_wincond.c | 232 | ||||
| -rw-r--r-- | mysys/my_winthread.c | 15 | ||||
| -rw-r--r-- | mysys/thr_rwlock.c | 160 |
3 files changed, 363 insertions, 44 deletions
diff --git a/mysys/my_wincond.c b/mysys/my_wincond.c index ad1636011db..58c09e332d6 100644 --- a/mysys/my_wincond.c +++ b/mysys/my_wincond.c @@ -24,7 +24,108 @@ #include <process.h> #include <sys/timeb.h> -int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr) + +/* + Windows native condition variables. We use runtime loading / function + pointers, because they are not available on XP +*/ + +/* Prototypes and function pointers for condition variable functions */ +typedef VOID (WINAPI * InitializeConditionVariableProc) + (PCONDITION_VARIABLE ConditionVariable); + +typedef BOOL (WINAPI * SleepConditionVariableCSProc) + (PCONDITION_VARIABLE ConditionVariable, + PCRITICAL_SECTION CriticalSection, + DWORD dwMilliseconds); + +typedef VOID (WINAPI * WakeAllConditionVariableProc) + (PCONDITION_VARIABLE ConditionVariable); + +typedef VOID (WINAPI * WakeConditionVariableProc) + (PCONDITION_VARIABLE ConditionVariable); + +static InitializeConditionVariableProc my_InitializeConditionVariable; +static SleepConditionVariableCSProc my_SleepConditionVariableCS; +static WakeAllConditionVariableProc my_WakeAllConditionVariable; +static WakeConditionVariableProc my_WakeConditionVariable; + + +/** + Indicates if we have native condition variables, + initialized first time pthread_cond_init is called. +*/ + +static BOOL have_native_conditions= FALSE; + + +/** + Check if native conditions can be used, load function pointers +*/ + +static void check_native_cond_availability(void) +{ + HMODULE module= GetModuleHandle("kernel32"); + + my_InitializeConditionVariable= (InitializeConditionVariableProc) + GetProcAddress(module, "InitializeConditionVariable"); + my_SleepConditionVariableCS= (SleepConditionVariableCSProc) + GetProcAddress(module, "SleepConditionVariableCS"); + my_WakeAllConditionVariable= (WakeAllConditionVariableProc) + GetProcAddress(module, "WakeAllConditionVariable"); + my_WakeConditionVariable= (WakeConditionVariableProc) + GetProcAddress(module, "WakeConditionVariable"); + + if (my_InitializeConditionVariable) + have_native_conditions= TRUE; +} + + + +/** + Convert abstime to milliseconds +*/ + +static DWORD get_milliseconds(const struct timespec *abstime) +{ + long long millis; + union ft64 now; + + if (abstime == NULL) + return INFINITE; + + GetSystemTimeAsFileTime(&now.ft); + + /* + Calculate time left to abstime + - subtract start time from current time(values are in 100ns units) + - convert to millisec by dividing with 10000 + */ + millis= (abstime->tv.i64 - now.i64) / 10000; + + /* Don't allow the timeout to be negative */ + if (millis < 0) + return 0; + + /* + Make sure the calculated timeout does not exceed original timeout + value which could cause "wait for ever" if system time changes + */ + if (millis > abstime->max_timeout_msec) + millis= abstime->max_timeout_msec; + + if (millis > UINT_MAX) + millis= UINT_MAX; + + return (DWORD)millis; +} + + +/* + Old (pre-vista) implementation using events +*/ + +static int legacy_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr) { cond->waiting= 0; InitializeCriticalSection(&cond->lock_waiting); @@ -53,7 +154,8 @@ int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr) return 0; } -int pthread_cond_destroy(pthread_cond_t *cond) + +static int legacy_cond_destroy(pthread_cond_t *cond) { DeleteCriticalSection(&cond->lock_waiting); @@ -65,48 +167,13 @@ int pthread_cond_destroy(pthread_cond_t *cond) } -int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) -{ - return pthread_cond_timedwait(cond,mutex,NULL); -} - - -int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, +static int legacy_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, struct timespec *abstime) { int result; - long timeout; - union ft64 now; - - if( abstime != NULL ) - { - GetSystemTimeAsFileTime(&now.ft); - - /* - Calculate time left to abstime - - subtract start time from current time(values are in 100ns units) - - convert to millisec by dividing with 10000 - */ - timeout= (long)((abstime->tv.i64 - now.i64) / 10000); - - /* Don't allow the timeout to be negative */ - if (timeout < 0) - timeout= 0L; - - /* - Make sure the calucated timeout does not exceed original timeout - value which could cause "wait for ever" if system time changes - */ - if (timeout > abstime->max_timeout_msec) - timeout= abstime->max_timeout_msec; - - } - else - { - /* No time specified; don't expire */ - timeout= INFINITE; - } + DWORD timeout; + timeout= get_milliseconds(abstime); /* Block access if previous broadcast hasn't finished. This is just for safety and should normally not @@ -142,7 +209,7 @@ int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, return result == WAIT_TIMEOUT ? ETIMEDOUT : 0; } -int pthread_cond_signal(pthread_cond_t *cond) +static int legacy_cond_signal(pthread_cond_t *cond) { EnterCriticalSection(&cond->lock_waiting); @@ -155,7 +222,7 @@ int pthread_cond_signal(pthread_cond_t *cond) } -int pthread_cond_broadcast(pthread_cond_t *cond) +static int legacy_cond_broadcast(pthread_cond_t *cond) { EnterCriticalSection(&cond->lock_waiting); /* @@ -177,6 +244,87 @@ int pthread_cond_broadcast(pthread_cond_t *cond) } +/* + Posix API functions. Just choose between native and legacy implementation. +*/ + +int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr) +{ + /* + Once initialization is used here rather than in my_init(), to + 1) avoid my_init() pitfalls- undefined order in which initialization should + run + 2) be potentially useful C++ (in static constructors that run before main()) + 3) just to simplify the API. + Also, the overhead of my_pthread_once is very small. + */ + static my_pthread_once_t once_control= MY_PTHREAD_ONCE_INIT; + my_pthread_once(&once_control, check_native_cond_availability); + + if (have_native_conditions) + { + my_InitializeConditionVariable(&cond->native_cond); + return 0; + } + else + return legacy_cond_init(cond, attr); +} + + +int pthread_cond_destroy(pthread_cond_t *cond) +{ + if (have_native_conditions) + return 0; /* no destroy function */ + else + return legacy_cond_destroy(cond); +} + + +int pthread_cond_broadcast(pthread_cond_t *cond) +{ + if (have_native_conditions) + { + my_WakeAllConditionVariable(&cond->native_cond); + return 0; + } + else + return legacy_cond_broadcast(cond); +} + + +int pthread_cond_signal(pthread_cond_t *cond) +{ + if (have_native_conditions) + { + my_WakeConditionVariable(&cond->native_cond); + return 0; + } + else + return legacy_cond_signal(cond); +} + + +int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, + struct timespec *abstime) +{ + if (have_native_conditions) + { + DWORD timeout= get_milliseconds(abstime); + if (!my_SleepConditionVariableCS(&cond->native_cond, mutex, timeout)) + return ETIMEDOUT; + return 0; + } + else + return legacy_cond_timedwait(cond, mutex, abstime); +} + + +int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) +{ + return pthread_cond_timedwait(cond, mutex, NULL); +} + + int pthread_attr_init(pthread_attr_t *connect_att) { connect_att->dwStackSize = 0; diff --git a/mysys/my_winthread.c b/mysys/my_winthread.c index aecb2f7cc78..49534370a2f 100644 --- a/mysys/my_winthread.c +++ b/mysys/my_winthread.c @@ -155,8 +155,19 @@ int pthread_cancel(pthread_t thread) int my_pthread_once(my_pthread_once_t *once_control, void (*init_routine)(void)) { - LONG state= InterlockedCompareExchange(once_control, MY_PTHREAD_ONCE_INPROGRESS, - MY_PTHREAD_ONCE_INIT); + LONG state; + + /* + Do "dirty" read to find out if initialization is already done, to + save an interlocked operation in common case. Memory barriers are ensured by + Visual C++ volatile implementation. + */ + if (*once_control == MY_PTHREAD_ONCE_DONE) + return 0; + + state= InterlockedCompareExchange(once_control, MY_PTHREAD_ONCE_INPROGRESS, + MY_PTHREAD_ONCE_INIT); + switch(state) { case MY_PTHREAD_ONCE_INIT: diff --git a/mysys/thr_rwlock.c b/mysys/thr_rwlock.c index 218cfb251c8..13651221d37 100644 --- a/mysys/thr_rwlock.c +++ b/mysys/thr_rwlock.c @@ -20,6 +20,119 @@ #if defined(NEED_MY_RW_LOCK) #include <errno.h> +#ifdef _WIN32 + +static BOOL have_srwlock= FALSE; +/* Prototypes and function pointers for windows functions */ +typedef VOID (WINAPI* srw_func) (PSRWLOCK SRWLock); +typedef BOOL (WINAPI* srw_bool_func) (PSRWLOCK SRWLock); + +static srw_func my_InitializeSRWLock; +static srw_func my_AcquireSRWLockExclusive; +static srw_func my_ReleaseSRWLockExclusive; +static srw_func my_AcquireSRWLockShared; +static srw_func my_ReleaseSRWLockShared; + +static srw_bool_func my_TryAcquireSRWLockExclusive; +static srw_bool_func my_TryAcquireSRWLockShared; + +/** + Check for presence of Windows slim reader writer lock function. + Load function pointers. +*/ + +static void check_srwlock_availability(void) +{ + HMODULE module= GetModuleHandle("kernel32"); + + my_InitializeSRWLock= (srw_func) GetProcAddress(module, + "InitializeSRWLock"); + my_AcquireSRWLockExclusive= (srw_func) GetProcAddress(module, + "AcquireSRWLockExclusive"); + my_AcquireSRWLockShared= (srw_func) GetProcAddress(module, + "AcquireSRWLockShared"); + my_ReleaseSRWLockExclusive= (srw_func) GetProcAddress(module, + "ReleaseSRWLockExclusive"); + my_ReleaseSRWLockShared= (srw_func) GetProcAddress(module, + "ReleaseSRWLockShared"); + my_TryAcquireSRWLockExclusive= (srw_bool_func) GetProcAddress(module, + "TryAcquireSRWLockExclusive"); + my_TryAcquireSRWLockShared= (srw_bool_func) GetProcAddress(module, + "TryAcquireSRWLockShared"); + + /* + We currently require TryAcquireSRWLockExclusive. This API is missing on + Vista, this means SRWLock are only used starting with Win7. + + If "trylock" usage for rwlocks is eliminated from server codebase (it is used + in a single place currently, in query cache), then SRWLock can be enabled on + Vista too. In this case condition below needs to be changed to e.g check + for my_InitializeSRWLock. + */ + + if (my_TryAcquireSRWLockExclusive) + have_srwlock= TRUE; + +} + + +static int srw_init(my_rw_lock_t *rwp) +{ + my_InitializeSRWLock(&rwp->srwlock); + rwp->have_exclusive_srwlock = FALSE; + return 0; +} + + +static int srw_rdlock(my_rw_lock_t *rwp) +{ + my_AcquireSRWLockShared(&rwp->srwlock); + return 0; +} + + +static int srw_tryrdlock(my_rw_lock_t *rwp) +{ + + if (!my_TryAcquireSRWLockShared(&rwp->srwlock)) + return EBUSY; + return 0; +} + + +static int srw_wrlock(my_rw_lock_t *rwp) +{ + my_AcquireSRWLockExclusive(&rwp->srwlock); + rwp->have_exclusive_srwlock= TRUE; + return 0; +} + + +static int srw_trywrlock(my_rw_lock_t *rwp) +{ + if (!my_TryAcquireSRWLockExclusive(&rwp->srwlock)) + return EBUSY; + rwp->have_exclusive_srwlock= TRUE; + return 0; +} + + +static int srw_unlock(my_rw_lock_t *rwp) +{ + if (rwp->have_exclusive_srwlock) + { + rwp->have_exclusive_srwlock= FALSE; + my_ReleaseSRWLockExclusive(&rwp->srwlock); + } + else + { + my_ReleaseSRWLockShared(&rwp->srwlock); + } + return 0; +} + +#endif /*_WIN32 */ + /* Source base from Sun Microsystems SPILT, simplified for MySQL use -- Joshua Chamas @@ -63,6 +176,22 @@ int my_rw_init(my_rw_lock_t *rwp) { pthread_condattr_t cond_attr; +#ifdef _WIN32 + /* + Once initialization is used here rather than in my_init(), in order to + - avoid my_init() pitfalls- (undefined order in which initialization should + run) + - be potentially useful C++ (static constructors) + - just to simplify the API. + Also, the overhead is of my_pthread_once is very small. + */ + static my_pthread_once_t once_control= MY_PTHREAD_ONCE_INIT; + my_pthread_once(&once_control, check_srwlock_availability); + + if (have_srwlock) + return srw_init(rwp); +#endif + pthread_mutex_init( &rwp->lock, MY_MUTEX_INIT_FAST); pthread_condattr_init( &cond_attr ); pthread_cond_init( &rwp->readers, &cond_attr ); @@ -81,6 +210,10 @@ int my_rw_init(my_rw_lock_t *rwp) int my_rw_destroy(my_rw_lock_t *rwp) { +#ifdef _WIN32 + if (have_srwlock) + return 0; /* no destroy function */ +#endif DBUG_ASSERT(rwp->state == 0); pthread_mutex_destroy( &rwp->lock ); pthread_cond_destroy( &rwp->readers ); @@ -91,6 +224,11 @@ int my_rw_destroy(my_rw_lock_t *rwp) int my_rw_rdlock(my_rw_lock_t *rwp) { +#ifdef _WIN32 + if (have_srwlock) + return srw_rdlock(rwp); +#endif + pthread_mutex_lock(&rwp->lock); /* active or queued writers */ @@ -105,6 +243,12 @@ int my_rw_rdlock(my_rw_lock_t *rwp) int my_rw_tryrdlock(my_rw_lock_t *rwp) { int res; + +#ifdef _WIN32 + if (have_srwlock) + return srw_tryrdlock(rwp); +#endif + pthread_mutex_lock(&rwp->lock); if ((rwp->state < 0 ) || rwp->waiters) res= EBUSY; /* Can't get lock */ @@ -120,6 +264,11 @@ int my_rw_tryrdlock(my_rw_lock_t *rwp) int my_rw_wrlock(my_rw_lock_t *rwp) { +#ifdef _WIN32 + if (have_srwlock) + return srw_wrlock(rwp); +#endif + pthread_mutex_lock(&rwp->lock); rwp->waiters++; /* another writer queued */ @@ -140,6 +289,12 @@ int my_rw_wrlock(my_rw_lock_t *rwp) int my_rw_trywrlock(my_rw_lock_t *rwp) { int res; + +#ifdef _WIN32 + if (have_srwlock) + return srw_trywrlock(rwp); +#endif + pthread_mutex_lock(&rwp->lock); if (rwp->state) res= EBUSY; /* Can't get lock */ @@ -158,6 +313,11 @@ int my_rw_trywrlock(my_rw_lock_t *rwp) int my_rw_unlock(my_rw_lock_t *rwp) { +#ifdef _WIN32 + if (have_srwlock) + return srw_unlock(rwp); +#endif + DBUG_PRINT("rw_unlock", ("state: %d waiters: %d", rwp->state, rwp->waiters)); pthread_mutex_lock(&rwp->lock); |