#include "univ.i"
#include "ut0lst.h"
#include "sync0types.h"
#include "os0sync.ic"

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Classes
struct	os_fast_mutex_t
struct	os_event

Macros
#define	OS_SYNC_INFINITE_TIME ULINT_UNDEFINED
#define	OS_SYNC_TIME_EXCEEDED 1
#define	os_event_wait(event) os_event_wait_low(event, 0)
#define	os_event_wait_time(event, t) os_event_wait_time_low(event, t, 0)
#define	os_fast_mutex_init(K, M) os_fast_mutex_init_func(&((os_fast_mutex_t*)(M))->mutex)
#define	os_fast_mutex_lock(M) os_fast_mutex_lock_func(&((os_fast_mutex_t*)(M))->mutex)
#define	os_fast_mutex_unlock(M) os_fast_mutex_unlock_func(&((os_fast_mutex_t*)(M))->mutex)
#define	os_fast_mutex_free(M) os_fast_mutex_free_func(&((os_fast_mutex_t*)(M))->mutex)
#define	IB_ATOMICS_STARTUP_MSG "Mutexes and rw_locks use InnoDB's own implementation"
#define	os_atomic_inc_ulint(m, v, d) os_atomic_inc_ulint_func(m, v, d)
#define	os_atomic_dec_ulint(m, v, d) os_atomic_dec_ulint_func(m, v, d)
#define	os_increment_counter_by_amount(mutex, counter, amount)
#define	os_decrement_counter_by_amount(mutex, counter, amount)
#define	os_inc_counter(mutex, counter) os_increment_counter_by_amount(mutex, counter, 1)
#define	os_dec_counter(mutex, counter)

Typedefs
typedef pthread_mutex_t	fast_mutex_t
typedef pthread_cond_t	os_cond_t
typedef struct os_event *	os_event_t
typedef struct os_mutex_t *	os_ib_mutex_t

Functions
UNIV_INTERN void	os_sync_init (void)
UNIV_INTERN void	os_sync_free (void)
UNIV_INTERN os_event_t	os_event_create (void)
UNIV_INTERN void	os_event_set (os_event_t event)
UNIV_INTERN ib_int64_t	os_event_reset (os_event_t event)
UNIV_INTERN void	os_event_free (os_event_t event)
UNIV_INTERN void	os_event_wait_low (os_event_t event, ib_int64_t reset_sig_count)
UNIV_INTERN ulint	os_event_wait_time_low (os_event_t event, ulint time_in_usec, ib_int64_t reset_sig_count)
UNIV_INTERN os_ib_mutex_t	os_mutex_create (void)
UNIV_INTERN void	os_mutex_enter (os_ib_mutex_t mutex)
UNIV_INTERN void	os_mutex_exit (os_ib_mutex_t mutex)
UNIV_INTERN void	os_mutex_free (os_ib_mutex_t mutex)
UNIV_INLINE ulint	os_fast_mutex_trylock (os_fast_mutex_t *fast_mutex)
UNIV_INTERN void	os_fast_mutex_unlock_func (fast_mutex_t *fast_mutex)
UNIV_INTERN void	os_fast_mutex_init_func (fast_mutex_t *fast_mutex)
UNIV_INTERN void	os_fast_mutex_lock_func (fast_mutex_t *fast_mutex)
UNIV_INTERN void	os_fast_mutex_free_func (fast_mutex_t *fast_mutex)

Variables
os_ib_mutex_t	os_sync_mutex
ulint	os_thread_count
ulint	os_event_count
ulint	os_mutex_count
ulint	os_fast_mutex_count

Detailed Description

The interface to the operating system synchronization primitives.

Created 9/6/1995 Heikki Tuuri

Definition in file os0sync.h.

Macro Definition Documentation

#define IB_ATOMICS_STARTUP_MSG "Mutexes and rw_locks use InnoDB's own implementation"

Atomic compare-and-swap and increment for InnoDB.

Definition at line 614 of file os0sync.h.

#define os_dec_counter	(	mutex,
		counter
	)

Value:

do {                                                    \
                os_decrement_counter_by_amount(mutex, counter, 1);\
        } while (0);

Definition at line 655 of file os0sync.h.

#define os_decrement_counter_by_amount	(	mutex,
		counter,
		amount
	)

Value:

do {                                                    \
                ut_a(counter >= amount);                        \
                mutex_enter(&(mutex));                          \
                (counter) -= (amount);                          \
                mutex_exit(&(mutex));                           \
        } while (0)

Definition at line 643 of file os0sync.h.

#define os_increment_counter_by_amount	(	mutex,
		counter,
		amount
	)

Value:

do {                                                    \
                mutex_enter(&(mutex));                          \
                (counter) += (amount);                          \
                mutex_exit(&(mutex));                           \
        } while (0)

Following macros are used to update specified counter atomically if HAVE_ATOMIC_BUILTINS defined. Otherwise, use mutex passed in for synchronization

Definition at line 636 of file os0sync.h.

#define OS_SYNC_INFINITE_TIME ULINT_UNDEFINED

Denotes an infinite delay for os_event_wait_time()

Definition at line 89 of file os0sync.h.

#define OS_SYNC_TIME_EXCEEDED 1

Return value of os_event_wait_time() when the time is exceeded

Definition at line 92 of file os0sync.h.

Typedef Documentation

typedef pthread_mutex_t fast_mutex_t

Native mutex

Definition at line 50 of file os0sync.h.

typedef pthread_cond_t os_cond_t

Native condition variable

Definition at line 52 of file os0sync.h.

typedef struct os_event* os_event_t

Operating system event handle

Definition at line 66 of file os0sync.h.

typedef struct os_mutex_t* os_ib_mutex_t

Operating system mutex handle

Definition at line 95 of file os0sync.h.

Function Documentation

UNIV_INTERN os_event_t os_event_create ( void )

Creates an event semaphore, i.e., a semaphore which may just have two states: signaled and nonsignaled. The created event is manual reset: it must be reset explicitly by calling sync_os_reset_event.

Returns: the event handle

Definition at line 368 of file os0sync.cc.

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UNIV_INTERN void os_event_free ( os_event_t event )

Frees an event object. in: event to free

Frees an event object.

Parameters

event in: event to free

Definition at line 532 of file os0sync.cc.

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UNIV_INTERN ib_int64_t os_event_reset ( os_event_t event )

Resets an event semaphore to the nonsignaled state. Waiting threads will stop to wait for the event. The return value should be passed to os_even_wait_low() if it is desired that this thread should not wait in case of an intervening call to os_event_set() between this os_event_reset() and the os_event_wait_low() call. See comments for os_event_wait_low(). in: event to reset

Resets an event semaphore to the nonsignaled state. Waiting threads will stop to wait for the event. The return value should be passed to os_even_wait_low() if it is desired that this thread should not wait in case of an intervening call to os_event_set() between this os_event_reset() and the os_event_wait_low() call. See comments for os_event_wait_low().

Returns: current signal_count.

Parameters

event in: event to reset

Definition at line 469 of file os0sync.cc.

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UNIV_INTERN void os_event_set ( os_event_t event )

Sets an event semaphore to the signaled state: lets waiting threads proceed. in: event to set

Sets an event semaphore to the signaled state: lets waiting threads proceed.

Parameters

event in: event to set

Definition at line 433 of file os0sync.cc.

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UNIV_INTERN void os_event_wait_low	(	os_event_t	event,
		ib_int64_t	reset_sig_count
	)

Waits for an event object until it is in the signaled state.

Typically, if the event has been signalled after the os_event_reset() we'll return immediately because event->is_set == TRUE. There are, however, situations (e.g.: sync_array code) where we may lose this information. For example:

thread A calls os_event_reset() thread B calls os_event_set() [event->is_set == TRUE] thread C calls os_event_reset() [event->is_set == FALSE] thread A calls os_event_wait() [infinite wait!] thread C calls os_event_wait() [infinite wait!]

Where such a scenario is possible, to avoid infinite wait, the value returned by os_event_reset() should be passed in as reset_sig_count. in: zero or the value returned by previous call of os_event_reset().

Waits for an event object until it is in the signaled state.

Typically, if the event has been signalled after the os_event_reset() we'll return immediately because event->is_set == TRUE. There are, however, situations (e.g.: sync_array code) where we may lose this information. For example:

thread A calls os_event_reset() thread B calls os_event_set() [event->is_set == TRUE] thread C calls os_event_reset() [event->is_set == FALSE] thread A calls os_event_wait() [infinite wait!] thread C calls os_event_wait() [infinite wait!]

Where such a scenario is possible, to avoid infinite wait, the value returned by os_event_reset() should be passed in as reset_sig_count.

Parameters

event	in: event to wait
reset_sig_count	in: zero or the value returned by previous call of os_event_reset().

Definition at line 580 of file os0sync.cc.

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UNIV_INTERN ulint os_event_wait_time_low	(	os_event_t	event,
		ulint	time_in_usec,
		ib_int64_t	reset_sig_count
	)

Waits for an event object until it is in the signaled state or a timeout is exceeded. In Unix the timeout is always infinite.

Returns: 0 if success, OS_SYNC_TIME_EXCEEDED if timeout was exceeded in: zero or the value returned by previous call of os_event_reset().

Waits for an event object until it is in the signaled state or a timeout is exceeded.

Returns: 0 if success, OS_SYNC_TIME_EXCEEDED if timeout was exceeded

Parameters

event	in: event to wait
time_in_usec	in: timeout in microseconds, or OS_SYNC_INFINITE_TIME
reset_sig_count	in: zero or the value returned by previous call of os_event_reset().

Definition at line 626 of file os0sync.cc.

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UNIV_INTERN void os_fast_mutex_free_func ( fast_mutex_t * fast_mutex )

Frees an mutex object. in: mutex to free

Frees a mutex object.

Parameters

fast_mutex in: mutex to free

Definition at line 896 of file os0sync.cc.

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UNIV_INTERN void os_fast_mutex_init_func ( fast_mutex_t * fast_mutex )

Initializes an operating system fast mutex semaphore. in: fast mutex

Initializes an operating system fast mutex semaphore.

Parameters

fast_mutex in: fast mutex

Definition at line 837 of file os0sync.cc.

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UNIV_INTERN void os_fast_mutex_lock_func ( fast_mutex_t * fast_mutex )

Acquires ownership of a fast mutex. in: mutex to acquire

Acquires ownership of a fast mutex.

Parameters

fast_mutex in: mutex to acquire

Definition at line 866 of file os0sync.cc.

UNIV_INLINE ulint os_fast_mutex_trylock ( os_fast_mutex_t * fast_mutex )

Acquires ownership of a fast mutex. Currently in Windows this is the same as os_fast_mutex_lock!

Returns: 0 if success, != 0 if was reserved by another thread in: mutex to acquire

UNIV_INTERN void os_fast_mutex_unlock_func ( fast_mutex_t * fast_mutex )

Releases ownership of a fast mutex. in: mutex to release

Releases ownership of a fast mutex.

Parameters

fast_mutex in: mutex to release

Definition at line 881 of file os0sync.cc.

UNIV_INTERN os_ib_mutex_t os_mutex_create ( void )

Creates an operating system mutex semaphore. Because these are slow, the mutex semaphore of InnoDB itself (ib_mutex_t) should be used where possible.

Returns: the mutex handle

Definition at line 738 of file os0sync.cc.

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UNIV_INTERN void os_mutex_enter ( os_ib_mutex_t mutex )

Acquires ownership of a mutex semaphore. in: mutex to acquire

Acquires ownership of a mutex semaphore.

Parameters

mutex in: mutex to acquire

Definition at line 775 of file os0sync.cc.

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UNIV_INTERN void os_mutex_exit ( os_ib_mutex_t mutex )

Releases ownership of a mutex. in: mutex to release

Releases ownership of a mutex.

Parameters

mutex in: mutex to release

Definition at line 790 of file os0sync.cc.

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UNIV_INTERN void os_mutex_free ( os_ib_mutex_t mutex )

Frees an mutex object. in: mutex to free

Frees a mutex object.

Parameters

mutex in: mutex to free

Definition at line 806 of file os0sync.cc.

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UNIV_INTERN void os_sync_free ( void )

Frees created events and OS 'slow' mutexes.

Definition at line 328 of file os0sync.cc.

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UNIV_INTERN void os_sync_init ( void )

Initializes global event and OS 'slow' mutex lists.

Definition at line 307 of file os0sync.cc.

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Variable Documentation

os_ib_mutex_t os_sync_mutex

Mutex protecting counts and the event and OS 'slow' mutex lists

Mutex protecting counts and the lists of OS mutexes and events

Definition at line 55 of file os0sync.cc.

ulint os_thread_count

This is incremented by 1 in os_thread_create and decremented by 1 in

os_thread_exit

Definition at line 63 of file os0sync.cc.

Classes

Macros

Typedefs

Functions

Variables

Detailed Description

Macro Definition Documentation

Typedef Documentation

Function Documentation

Variable Documentation