diff options
Diffstat (limited to 'storage/xtradb/sync/sync0arr.c')
| -rw-r--r-- | storage/xtradb/sync/sync0arr.c | 205 |
1 files changed, 104 insertions, 101 deletions
diff --git a/storage/xtradb/sync/sync0arr.c b/storage/xtradb/sync/sync0arr.c index 62165eefd46..0519e13dee0 100644 --- a/storage/xtradb/sync/sync0arr.c +++ b/storage/xtradb/sync/sync0arr.c @@ -23,7 +23,8 @@ Place, Suite 330, Boston, MA 02111-1307 USA *****************************************************************************/ -/****************************************************** +/**************************************************//** +@file sync/sync0arr.c The wait array used in synchronization primitives Created 9/5/1995 Heikki Tuuri @@ -73,27 +74,29 @@ wait array for the sake of diagnostics and also to avoid infinite wait The error_monitor thread scans the global wait array to signal any waiting threads who have missed the signal. */ -/* A cell where an individual thread may wait suspended +/** A cell where an individual thread may wait suspended until a resource is released. The suspending is implemented using an operating system event semaphore. */ struct sync_cell_struct { - void* wait_object; /* pointer to the object the + void* wait_object; /*!< pointer to the object the thread is waiting for; if NULL the cell is free for use */ - mutex_t* old_wait_mutex; /* the latest wait mutex in cell */ - rw_lock_t* old_wait_rw_lock;/* the latest wait rw-lock in cell */ - ulint request_type; /* lock type requested on the + mutex_t* old_wait_mutex; /*!< the latest wait mutex in cell */ + rw_lock_t* old_wait_rw_lock; + /*!< the latest wait rw-lock + in cell */ + ulint request_type; /*!< lock type requested on the object */ - const char* file; /* in debug version file where + const char* file; /*!< in debug version file where requested */ - ulint line; /* in debug version line where + ulint line; /*!< in debug version line where requested */ - os_thread_id_t thread; /* thread id of this waiting + os_thread_id_t thread; /*!< thread id of this waiting thread */ - ibool waiting; /* TRUE if the thread has already + ibool waiting; /*!< TRUE if the thread has already called sync_array_event_wait on this cell */ - ib_int64_t signal_count; /* We capture the signal_count + ib_int64_t signal_count; /*!< We capture the signal_count of the wait_object when we reset the event. This value is then passed on to os_event_wait @@ -101,7 +104,7 @@ struct sync_cell_struct { has not been signalled in the period between the reset and wait call. */ - time_t reservation_time;/* time when the thread reserved + time_t reservation_time;/*!< time when the thread reserved the wait cell */ }; @@ -110,54 +113,56 @@ for an event allocated for the array without owning the protecting mutex (depending on the case: OS or database mutex), but all changes (set or reset) to the state of the event must be made while owning the mutex. */ + +/** Synchronization array */ struct sync_array_struct { - ulint n_reserved; /* number of currently reserved + ulint n_reserved; /*!< number of currently reserved cells in the wait array */ - ulint n_cells; /* number of cells in the + ulint n_cells; /*!< number of cells in the wait array */ - sync_cell_t* array; /* pointer to wait array */ - ulint protection; /* this flag tells which + sync_cell_t* array; /*!< pointer to wait array */ + ulint protection; /*!< this flag tells which mutex protects the data */ - mutex_t mutex; /* possible database mutex + mutex_t mutex; /*!< possible database mutex protecting this data structure */ - os_mutex_t os_mutex; /* Possible operating system mutex + os_mutex_t os_mutex; /*!< Possible operating system mutex protecting the data structure. As this data structure is used in constructing the database mutex, to prevent infinite recursion in implementation, we fall back to an OS mutex. */ - ulint sg_count; /* count of how many times an + ulint sg_count; /*!< count of how many times an object has been signalled */ - ulint res_count; /* count of cell reservations + ulint res_count; /*!< count of cell reservations since creation of the array */ }; #ifdef UNIV_SYNC_DEBUG -/********************************************************************** +/******************************************************************//** This function is called only in the debug version. Detects a deadlock -of one or more threads because of waits of semaphores. */ +of one or more threads because of waits of semaphores. +@return TRUE if deadlock detected */ static ibool sync_array_detect_deadlock( /*=======================*/ - /* out: TRUE if deadlock detected */ - sync_array_t* arr, /* in: wait array; NOTE! the caller must + sync_array_t* arr, /*!< in: wait array; NOTE! the caller must own the mutex to array */ - sync_cell_t* start, /* in: cell where recursive search started */ - sync_cell_t* cell, /* in: cell to search */ - ulint depth); /* in: recursion depth */ + sync_cell_t* start, /*!< in: cell where recursive search started */ + sync_cell_t* cell, /*!< in: cell to search */ + ulint depth); /*!< in: recursion depth */ #endif /* UNIV_SYNC_DEBUG */ -/********************************************************************* -Gets the nth cell in array. */ +/*****************************************************************//** +Gets the nth cell in array. +@return cell */ static sync_cell_t* sync_array_get_nth_cell( /*====================*/ - /* out: cell */ - sync_array_t* arr, /* in: sync array */ - ulint n) /* in: index */ + sync_array_t* arr, /*!< in: sync array */ + ulint n) /*!< in: index */ { ut_a(arr); ut_a(n < arr->n_cells); @@ -165,13 +170,13 @@ sync_array_get_nth_cell( return(arr->array + n); } -/********************************************************************** +/******************************************************************//** Reserves the mutex semaphore protecting a sync array. */ static void sync_array_enter( /*=============*/ - sync_array_t* arr) /* in: sync wait array */ + sync_array_t* arr) /*!< in: sync wait array */ { ulint protection; @@ -186,13 +191,13 @@ sync_array_enter( } } -/********************************************************************** +/******************************************************************//** Releases the mutex semaphore protecting a sync array. */ static void sync_array_exit( /*============*/ - sync_array_t* arr) /* in: sync wait array */ + sync_array_t* arr) /*!< in: sync wait array */ { ulint protection; @@ -207,18 +212,18 @@ sync_array_exit( } } -/*********************************************************************** +/*******************************************************************//** Creates a synchronization wait array. It is protected by a mutex which is automatically reserved when the functions operating on it -are called. */ +are called. +@return own: created wait array */ UNIV_INTERN sync_array_t* sync_array_create( /*==============*/ - /* out, own: created wait array */ - ulint n_cells, /* in: number of cells in the array + ulint n_cells, /*!< in: number of cells in the array to create */ - ulint protection) /* in: either SYNC_ARRAY_OS_MUTEX or + ulint protection) /*!< in: either SYNC_ARRAY_OS_MUTEX or SYNC_ARRAY_MUTEX: determines the type of mutex protecting the data structure */ { @@ -260,13 +265,13 @@ sync_array_create( return(arr); } -/********************************************************************** +/******************************************************************//** Frees the resources in a wait array. */ UNIV_INTERN void sync_array_free( /*============*/ - sync_array_t* arr) /* in, own: sync wait array */ + sync_array_t* arr) /*!< in, own: sync wait array */ { ulint protection; @@ -290,14 +295,14 @@ sync_array_free( ut_free(arr); } -/************************************************************************ +/********************************************************************//** Validates the integrity of the wait array. Checks that the number of reserved cells equals the count variable. */ UNIV_INTERN void sync_array_validate( /*================*/ - sync_array_t* arr) /* in: sync wait array */ + sync_array_t* arr) /*!< in: sync wait array */ { ulint i; sync_cell_t* cell; @@ -317,13 +322,13 @@ sync_array_validate( sync_array_exit(arr); } -/*********************************************************************** +/*******************************************************************//** Returns the event that the thread owning the cell waits for. */ static os_event_t sync_cell_get_event( /*================*/ - sync_cell_t* cell) /* in: non-empty sync array cell */ + sync_cell_t* cell) /*!< in: non-empty sync array cell */ { ulint type = cell->request_type; @@ -336,19 +341,19 @@ sync_cell_get_event( } } -/********************************************************************** +/******************************************************************//** Reserves a wait array cell for waiting for an object. The event of the cell is reset to nonsignalled state. */ UNIV_INTERN void sync_array_reserve_cell( /*====================*/ - sync_array_t* arr, /* in: wait array */ - void* object, /* in: pointer to the object to wait for */ - ulint type, /* in: lock request type */ - const char* file, /* in: file where requested */ - ulint line, /* in: line where requested */ - ulint* index) /* out: index of the reserved cell */ + sync_array_t* arr, /*!< in: wait array */ + void* object, /*!< in: pointer to the object to wait for */ + ulint type, /*!< in: lock request type */ + const char* file, /*!< in: file where requested */ + ulint line, /*!< in: line where requested */ + ulint* index) /*!< out: index of the reserved cell */ { sync_cell_t* cell; os_event_t event; @@ -406,7 +411,7 @@ sync_array_reserve_cell( return; } -/********************************************************************** +/******************************************************************//** This function should be called when a thread starts to wait on a wait array cell. In the debug version this function checks if the wait for a semaphore will result in a deadlock, in which @@ -415,8 +420,8 @@ UNIV_INTERN void sync_array_wait_event( /*==================*/ - sync_array_t* arr, /* in: wait array */ - ulint index) /* in: index of the reserved cell */ + sync_array_t* arr, /*!< in: wait array */ + ulint index) /*!< in: index of the reserved cell */ { sync_cell_t* cell; os_event_t event; @@ -458,14 +463,14 @@ sync_array_wait_event( sync_array_free_cell(arr, index); } -/********************************************************************** +/******************************************************************//** Reports info of a wait array cell. */ static void sync_array_cell_print( /*==================*/ - FILE* file, /* in: file where to print */ - sync_cell_t* cell) /* in: sync cell */ + FILE* file, /*!< in: file where to print */ + sync_cell_t* cell) /*!< in: sync cell */ { mutex_t* mutex; rw_lock_t* rwlock; @@ -544,16 +549,15 @@ sync_array_cell_print( } #ifdef UNIV_SYNC_DEBUG -/********************************************************************** -Looks for a cell with the given thread id. */ +/******************************************************************//** +Looks for a cell with the given thread id. +@return pointer to cell or NULL if not found */ static sync_cell_t* sync_array_find_thread( /*===================*/ - /* out: pointer to cell or NULL - if not found */ - sync_array_t* arr, /* in: wait array */ - os_thread_id_t thread) /* in: thread id */ + sync_array_t* arr, /*!< in: wait array */ + os_thread_id_t thread) /*!< in: thread id */ { ulint i; sync_cell_t* cell; @@ -572,20 +576,20 @@ sync_array_find_thread( return(NULL); /* Not found */ } -/********************************************************************** -Recursion step for deadlock detection. */ +/******************************************************************//** +Recursion step for deadlock detection. +@return TRUE if deadlock detected */ static ibool sync_array_deadlock_step( /*=====================*/ - /* out: TRUE if deadlock detected */ - sync_array_t* arr, /* in: wait array; NOTE! the caller must + sync_array_t* arr, /*!< in: wait array; NOTE! the caller must own the mutex to array */ - sync_cell_t* start, /* in: cell where recursive search + sync_cell_t* start, /*!< in: cell where recursive search started */ - os_thread_id_t thread, /* in: thread to look at */ - ulint pass, /* in: pass value */ - ulint depth) /* in: recursion depth */ + os_thread_id_t thread, /*!< in: thread to look at */ + ulint pass, /*!< in: pass value */ + ulint depth) /*!< in: recursion depth */ { sync_cell_t* new; ibool ret; @@ -623,19 +627,19 @@ sync_array_deadlock_step( return(FALSE); } -/********************************************************************** +/******************************************************************//** This function is called only in the debug version. Detects a deadlock -of one or more threads because of waits of semaphores. */ +of one or more threads because of waits of semaphores. +@return TRUE if deadlock detected */ static ibool sync_array_detect_deadlock( /*=======================*/ - /* out: TRUE if deadlock detected */ - sync_array_t* arr, /* in: wait array; NOTE! the caller must + sync_array_t* arr, /*!< in: wait array; NOTE! the caller must own the mutex to array */ - sync_cell_t* start, /* in: cell where recursive search started */ - sync_cell_t* cell, /* in: cell to search */ - ulint depth) /* in: recursion depth */ + sync_cell_t* start, /*!< in: cell where recursive search started */ + sync_cell_t* cell, /*!< in: cell to search */ + ulint depth) /*!< in: recursion depth */ { mutex_t* mutex; rw_lock_t* lock; @@ -768,13 +772,13 @@ print: } #endif /* UNIV_SYNC_DEBUG */ -/********************************************************************** +/******************************************************************//** Determines if we can wake up the thread waiting for a sempahore. */ static ibool sync_arr_cell_can_wake_up( /*======================*/ - sync_cell_t* cell) /* in: cell to search */ + sync_cell_t* cell) /*!< in: cell to search */ { mutex_t* mutex; rw_lock_t* lock; @@ -820,15 +824,15 @@ sync_arr_cell_can_wake_up( return(FALSE); } -/********************************************************************** +/******************************************************************//** Frees the cell. NOTE! sync_array_wait_event frees the cell automatically! */ UNIV_INTERN void sync_array_free_cell( /*=================*/ - sync_array_t* arr, /* in: wait array */ - ulint index) /* in: index of the cell in array */ + sync_array_t* arr, /*!< in: wait array */ + ulint index) /*!< in: index of the cell in array */ { sync_cell_t* cell; @@ -848,16 +852,16 @@ sync_array_free_cell( sync_array_exit(arr); } -/************************************************************************** +/**********************************************************************//** Increments the signalled count. */ UNIV_INTERN void sync_array_object_signalled( /*========================*/ - sync_array_t* arr) /* in: wait array */ + sync_array_t* arr) /*!< in: wait array */ { -#ifdef HAVE_GCC_ATOMIC_BUILTINS - (void) os_atomic_increment(&arr->sg_count, 1); +#ifdef HAVE_ATOMIC_BUILTINS + (void) os_atomic_increment_ulint(&arr->sg_count, 1); #else sync_array_enter(arr); @@ -867,7 +871,7 @@ sync_array_object_signalled( #endif } -/************************************************************************** +/**********************************************************************//** If the wakeup algorithm does not work perfectly at semaphore relases, this function will do the waking (see the comment in mutex_exit). This function should be called about every 1 second in the server. @@ -913,14 +917,13 @@ sync_arr_wake_threads_if_sema_free(void) sync_array_exit(arr); } -/************************************************************************** -Prints warnings of long semaphore waits to stderr. */ +/**********************************************************************//** +Prints warnings of long semaphore waits to stderr. +@return TRUE if fatal semaphore wait threshold was exceeded */ UNIV_INTERN ibool sync_array_print_long_waits(void) /*=============================*/ - /* out: TRUE if fatal semaphore wait threshold - was exceeded */ { sync_cell_t* cell; ibool old_val; @@ -979,14 +982,14 @@ sync_array_print_long_waits(void) return(fatal); } -/************************************************************************** +/**********************************************************************//** Prints info of the wait array. */ static void sync_array_output_info( /*===================*/ - FILE* file, /* in: file where to print */ - sync_array_t* arr) /* in: wait array; NOTE! caller must own the + FILE* file, /*!< in: file where to print */ + sync_array_t* arr) /*!< in: wait array; NOTE! caller must own the mutex */ { sync_cell_t* cell; @@ -1012,14 +1015,14 @@ sync_array_output_info( } } -/************************************************************************** +/**********************************************************************//** Prints info of the wait array. */ UNIV_INTERN void sync_array_print_info( /*==================*/ - FILE* file, /* in: file where to print */ - sync_array_t* arr) /* in: wait array */ + FILE* file, /*!< in: file where to print */ + sync_array_t* arr) /*!< in: wait array */ { sync_array_enter(arr); |