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Diffstat (limited to 'storage/xtradb/include/os0sync.h')
| -rw-r--r-- | storage/xtradb/include/os0sync.h | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/storage/xtradb/include/os0sync.h b/storage/xtradb/include/os0sync.h new file mode 100644 index 00000000000..7e058266762 --- /dev/null +++ b/storage/xtradb/include/os0sync.h @@ -0,0 +1,309 @@ +/***************************************************************************** + +Copyright (c) 1995, 2009, Innobase Oy. All Rights Reserved. +Copyright (c) 2008, Google Inc. + +Portions of this file contain modifications contributed and copyrighted by +Google, Inc. Those modifications are gratefully acknowledged and are described +briefly in the InnoDB documentation. The contributions by Google are +incorporated with their permission, and subject to the conditions contained in +the file COPYING.Google. + +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., 59 Temple +Place, Suite 330, Boston, MA 02111-1307 USA + +*****************************************************************************/ + +/****************************************************** +The interface to the operating system +synchronization primitives. + +Created 9/6/1995 Heikki Tuuri +*******************************************************/ + +#ifndef os0sync_h +#define os0sync_h + +#include "univ.i" +#include "ut0lst.h" + +#ifdef __WIN__ + +#define os_fast_mutex_t CRITICAL_SECTION + +typedef HANDLE os_native_event_t; + +typedef struct os_event_struct os_event_struct_t; +typedef os_event_struct_t* os_event_t; + +struct os_event_struct { + os_native_event_t handle; + /* Windows event */ + UT_LIST_NODE_T(os_event_struct_t) os_event_list; + /* list of all created events */ +}; +#else +typedef pthread_mutex_t os_fast_mutex_t; + +typedef struct os_event_struct os_event_struct_t; +typedef os_event_struct_t* os_event_t; + +struct os_event_struct { + os_fast_mutex_t os_mutex; /* this mutex protects the next + fields */ + ibool is_set; /* this is TRUE when the event is + in the signaled state, i.e., a thread + does not stop if it tries to wait for + this event */ + ib_int64_t signal_count; /* this is incremented each time + the event becomes signaled */ + pthread_cond_t cond_var; /* condition variable is used in + waiting for the event */ + UT_LIST_NODE_T(os_event_struct_t) os_event_list; + /* list of all created events */ +}; +#endif + +typedef struct os_mutex_struct os_mutex_str_t; +typedef os_mutex_str_t* os_mutex_t; + +#define OS_SYNC_INFINITE_TIME ((ulint)(-1)) + +#define OS_SYNC_TIME_EXCEEDED 1 + +/* Mutex protecting counts and the event and OS 'slow' mutex lists */ +extern os_mutex_t os_sync_mutex; + +/* This is incremented by 1 in os_thread_create and decremented by 1 in +os_thread_exit */ +extern ulint os_thread_count; + +extern ulint os_event_count; +extern ulint os_mutex_count; +extern ulint os_fast_mutex_count; + +/************************************************************* +Initializes global event and OS 'slow' mutex lists. */ +UNIV_INTERN +void +os_sync_init(void); +/*==============*/ +/************************************************************* +Frees created events and OS 'slow' mutexes. */ +UNIV_INTERN +void +os_sync_free(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. */ +UNIV_INTERN +os_event_t +os_event_create( +/*============*/ + /* out: the event handle */ + const char* name); /* in: the name of the event, if NULL + the event is created without a name */ +#ifdef __WIN__ +/************************************************************* +Creates an auto-reset event semaphore, i.e., an event which is automatically +reset when a single thread is released. Works only in Windows. */ +UNIV_INTERN +os_event_t +os_event_create_auto( +/*=================*/ + /* out: the event handle */ + const char* name); /* in: the name of the event, if NULL + the event is created without a name */ +#endif +/************************************************************** +Sets an event semaphore to the signaled state: lets waiting threads +proceed. */ +UNIV_INTERN +void +os_event_set( +/*=========*/ + os_event_t event); /* in: event to set */ +/************************************************************** +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(). */ +UNIV_INTERN +ib_int64_t +os_event_reset( +/*===========*/ + os_event_t event); /* in: event to reset */ +/************************************************************** +Frees an event object. */ +UNIV_INTERN +void +os_event_free( +/*==========*/ + os_event_t event); /* in: event to free */ + +/************************************************************** +Waits for an event object until it is in the signaled state. If +srv_shutdown_state == SRV_SHUTDOWN_EXIT_THREADS this also exits the +waiting thread when the event becomes signaled (or immediately if the +event is already 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. */ +UNIV_INTERN +void +os_event_wait_low( +/*==============*/ + os_event_t event, /* in: event to wait */ + ib_int64_t reset_sig_count);/* in: zero or the value + returned by previous call of + os_event_reset(). */ + +#define os_event_wait(event) os_event_wait_low(event, 0) + +/************************************************************** +Waits for an event object until it is in the signaled state or +a timeout is exceeded. In Unix the timeout is always infinite. */ +UNIV_INTERN +ulint +os_event_wait_time( +/*===============*/ + /* out: 0 if success, + OS_SYNC_TIME_EXCEEDED if timeout + was exceeded */ + os_event_t event, /* in: event to wait */ + ulint time); /* in: timeout in microseconds, or + OS_SYNC_INFINITE_TIME */ +#ifdef __WIN__ +/************************************************************** +Waits for any event in an OS native event array. Returns if even a single +one is signaled or becomes signaled. */ +UNIV_INTERN +ulint +os_event_wait_multiple( +/*===================*/ + /* out: index of the event + which was signaled */ + ulint n, /* in: number of events in the + array */ + os_native_event_t* native_event_array); + /* in: pointer to an array of event + handles */ +#endif +/************************************************************* +Creates an operating system mutex semaphore. Because these are slow, the +mutex semaphore of InnoDB itself (mutex_t) should be used where possible. */ +UNIV_INTERN +os_mutex_t +os_mutex_create( +/*============*/ + /* out: the mutex handle */ + const char* name); /* in: the name of the mutex, if NULL + the mutex is created without a name */ +/************************************************************** +Acquires ownership of a mutex semaphore. */ +UNIV_INTERN +void +os_mutex_enter( +/*===========*/ + os_mutex_t mutex); /* in: mutex to acquire */ +/************************************************************** +Releases ownership of a mutex. */ +UNIV_INTERN +void +os_mutex_exit( +/*==========*/ + os_mutex_t mutex); /* in: mutex to release */ +/************************************************************** +Frees an mutex object. */ +UNIV_INTERN +void +os_mutex_free( +/*==========*/ + os_mutex_t mutex); /* in: mutex to free */ +/************************************************************** +Acquires ownership of a fast mutex. Currently in Windows this is the same +as os_fast_mutex_lock! */ +UNIV_INLINE +ulint +os_fast_mutex_trylock( +/*==================*/ + /* out: 0 if success, != 0 if + was reserved by another + thread */ + os_fast_mutex_t* fast_mutex); /* in: mutex to acquire */ +/************************************************************** +Releases ownership of a fast mutex. */ +UNIV_INTERN +void +os_fast_mutex_unlock( +/*=================*/ + os_fast_mutex_t* fast_mutex); /* in: mutex to release */ +/************************************************************* +Initializes an operating system fast mutex semaphore. */ +UNIV_INTERN +void +os_fast_mutex_init( +/*===============*/ + os_fast_mutex_t* fast_mutex); /* in: fast mutex */ +/************************************************************** +Acquires ownership of a fast mutex. */ +UNIV_INTERN +void +os_fast_mutex_lock( +/*===============*/ + os_fast_mutex_t* fast_mutex); /* in: mutex to acquire */ +/************************************************************** +Frees an mutex object. */ +UNIV_INTERN +void +os_fast_mutex_free( +/*===============*/ + os_fast_mutex_t* fast_mutex); /* in: mutex to free */ + +#ifdef HAVE_GCC_ATOMIC_BUILTINS +/************************************************************** +Atomic compare-and-swap for InnoDB. Currently requires GCC atomic builtins. +Returns true if swapped, ptr is pointer to target, old_val is value to +compare to, new_val is the value to swap in. */ +#define os_compare_and_swap(ptr, old_val, new_val) \ + __sync_bool_compare_and_swap(ptr, old_val, new_val) + +/************************************************************** +Atomic increment for InnoDB. Currently requires GCC atomic builtins. +Returns the resulting value, ptr is pointer to target, amount is the +amount of increment. */ +#define os_atomic_increment(ptr, amount) \ + __sync_add_and_fetch(ptr, amount) + +#endif /* HAVE_GCC_ATOMIC_BUILTINS */ + +#ifndef UNIV_NONINL +#include "os0sync.ic" +#endif + +#endif |