/****************************************************** Mutex, the basic synchronization primitive (c) 1995 Innobase Oy Created 9/5/1995 Heikki Tuuri *******************************************************/ #ifndef sync0sync_h #define sync0sync_h #include "univ.i" #include "sync0types.h" #include "ut0lst.h" #include "ut0mem.h" #include "os0thread.h" #include "os0sync.h" #include "sync0arr.h" #ifndef UNIV_HOTBACKUP extern bool timed_mutexes; #endif /* UNIV_HOTBACKUP */ /********************************************************************** Initializes the synchronization data structures. */ void sync_init(void); /*===========*/ /********************************************************************** Frees the resources in synchronization data structures. */ void sync_close(void); /*===========*/ /********************************************************************** Creates, or rather, initializes a mutex object to a specified memory location (which must be appropriately aligned). The mutex is initialized in the reset state. Explicit freeing of the mutex with mutex_free is necessary only if the memory block containing it is freed. */ #ifdef UNIV_DEBUG # ifdef UNIV_SYNC_DEBUG # define mutex_create(M, level) \ mutex_create_func((M), #M, (level), __FILE__, __LINE__) # else # define mutex_create(M, level) \ mutex_create_func((M), #M, __FILE__, __LINE__) # endif #else # define mutex_create(M, level) \ mutex_create_func((M), __FILE__, __LINE__) #endif /********************************************************************** Creates, or rather, initializes a mutex object in a specified memory location (which must be appropriately aligned). The mutex is initialized in the reset state. Explicit freeing of the mutex with mutex_free is necessary only if the memory block containing it is freed. */ void mutex_create_func( /*==============*/ mutex_t* mutex, /* in: pointer to memory */ #ifdef UNIV_DEBUG const char* cmutex_name, /* in: mutex name */ # ifdef UNIV_SYNC_DEBUG ulint level, /* in: level */ # endif /* UNIV_SYNC_DEBUG */ #endif /* UNIV_DEBUG */ const char* cfile_name, /* in: file name where created */ ulint cline); /* in: file line where created */ /********************************************************************** Calling this function is obligatory only if the memory buffer containing the mutex is freed. Removes a mutex object from the mutex list. The mutex is checked to be in the reset state. */ #undef mutex_free /* Fix for MacOS X */ void mutex_free( /*=======*/ mutex_t* mutex); /* in: mutex */ /****************************************************************** NOTE! The following macro should be used in mutex locking, not the corresponding function. */ #define mutex_enter(M) mutex_enter_func((M), __FILE__, __LINE__) /********************************************************************** A noninlined function that reserves a mutex. In ha_innodb.cc we have disabled inlining of InnoDB functions, and no inlined functions should be called from there. That is why we need to duplicate the inlined function here. */ void mutex_enter_noninline( /*==================*/ mutex_t* mutex); /* in: mutex */ /****************************************************************** NOTE! The following macro should be used in mutex locking, not the corresponding function. */ /* NOTE! currently same as mutex_enter! */ #define mutex_enter_fast(M) mutex_enter_func((M), __FILE__, __LINE__) #define mutex_enter_fast_func mutex_enter_func; /********************************************************************** NOTE! Use the corresponding macro in the header file, not this function directly. Locks a mutex for the current thread. If the mutex is reserved the function spins a preset time (controlled by SYNC_SPIN_ROUNDS) waiting for the mutex before suspending the thread. */ UNIV_INLINE void mutex_enter_func( /*=============*/ mutex_t* mutex, /* in: pointer to mutex */ const char* file_name, /* in: file name where locked */ ulint line); /* in: line where locked */ /****************************************************************** NOTE! The following macro should be used in mutex locking, not the corresponding function. */ #define mutex_enter_nowait(M) \ mutex_enter_nowait_func((M), __FILE__, __LINE__) /************************************************************************ NOTE! Use the corresponding macro in the header file, not this function directly. Tries to lock the mutex for the current thread. If the lock is not acquired immediately, returns with return value 1. */ ulint mutex_enter_nowait_func( /*====================*/ /* out: 0 if succeed, 1 if not */ mutex_t* mutex, /* in: pointer to mutex */ const char* file_name, /* in: file name where mutex requested */ ulint line); /* in: line where requested */ /********************************************************************** Unlocks a mutex owned by the current thread. */ UNIV_INLINE void mutex_exit( /*=======*/ mutex_t* mutex); /* in: pointer to mutex */ /********************************************************************** Releases a mutex. */ void mutex_exit_noninline( /*=================*/ mutex_t* mutex); /* in: mutex */ /********************************************************************** Returns TRUE if no mutex or rw-lock is currently locked. Works only in the debug version. */ ibool sync_all_freed(void); /*================*/ /*##################################################################### FUNCTION PROTOTYPES FOR DEBUGGING */ /*********************************************************************** Prints wait info of the sync system. */ void sync_print_wait_info( /*=================*/ FILE* file); /* in: file where to print */ /*********************************************************************** Prints info of the sync system. */ void sync_print( /*=======*/ FILE* file); /* in: file where to print */ #ifdef UNIV_DEBUG /********************************************************************** Checks that the mutex has been initialized. */ ibool mutex_validate( /*===========*/ const mutex_t* mutex); /********************************************************************** Checks that the current thread owns the mutex. Works only in the debug version. */ ibool mutex_own( /*======*/ /* out: TRUE if owns */ const mutex_t* mutex); /* in: mutex */ #endif /* UNIV_DEBUG */ #ifdef UNIV_SYNC_DEBUG /********************************************************************** Adds a latch and its level in the thread level array. Allocates the memory for the array if called first time for this OS thread. Makes the checks against other latch levels stored in the array for this thread. */ void sync_thread_add_level( /*==================*/ void* latch, /* in: pointer to a mutex or an rw-lock */ ulint level); /* in: level in the latching order; if SYNC_LEVEL_VARYING, nothing is done */ /********************************************************************** Removes a latch from the thread level array if it is found there. */ ibool sync_thread_reset_level( /*====================*/ /* out: TRUE if found from the array; it is no error if the latch is not found, as we presently are not able to determine the level for every latch reservation the program does */ void* latch); /* in: pointer to a mutex or an rw-lock */ /********************************************************************** Checks that the level array for the current thread is empty. */ ibool sync_thread_levels_empty(void); /*==========================*/ /* out: TRUE if empty */ /********************************************************************** Checks that the level array for the current thread is empty. */ ibool sync_thread_levels_empty_gen( /*=========================*/ /* out: TRUE if empty except the exceptions specified below */ ibool dict_mutex_allowed); /* in: TRUE if dictionary mutex is allowed to be owned by the thread, also purge_is_running mutex is allowed */ /********************************************************************** Gets the debug information for a reserved mutex. */ void mutex_get_debug_info( /*=================*/ mutex_t* mutex, /* in: mutex */ const char** file_name, /* out: file where requested */ ulint* line, /* out: line where requested */ os_thread_id_t* thread_id); /* out: id of the thread which owns the mutex */ /********************************************************************** Counts currently reserved mutexes. Works only in the debug version. */ ulint mutex_n_reserved(void); /*==================*/ #endif /* UNIV_SYNC_DEBUG */ /********************************************************************** NOT to be used outside this module except in debugging! Gets the value of the lock word. */ UNIV_INLINE ulint mutex_get_lock_word( /*================*/ const mutex_t* mutex); /* in: mutex */ #ifdef UNIV_SYNC_DEBUG /********************************************************************** NOT to be used outside this module except in debugging! Gets the waiters field in a mutex. */ UNIV_INLINE ulint mutex_get_waiters( /*==============*/ /* out: value to set */ const mutex_t* mutex); /* in: mutex */ #endif /* UNIV_SYNC_DEBUG */ /* LATCHING ORDER WITHIN THE DATABASE ================================== The mutex or latch in the central memory object, for instance, a rollback segment object, must be acquired before acquiring the latch or latches to the corresponding file data structure. In the latching order below, these file page object latches are placed immediately below the corresponding central memory object latch or mutex. Synchronization object Notes ---------------------- ----- Dictionary mutex If we have a pointer to a dictionary | object, e.g., a table, it can be | accessed without reserving the | dictionary mutex. We must have a | reservation, a memoryfix, to the | appropriate table object in this case, | and the table must be explicitly | released later. V Dictionary header | V Secondary index tree latch The tree latch protects also all | the B-tree non-leaf pages. These V can be read with the page only Secondary index non-leaf bufferfixed to save CPU time, | no s-latch is needed on the page. | Modification of a page requires an | x-latch on the page, however. If a | thread owns an x-latch to the tree, | it is allowed to latch non-leaf pages | even after it has acquired the fsp | latch. V Secondary index leaf The latch on the secondary index leaf | can be kept while accessing the | clustered index, to save CPU time. V Clustered index tree latch To increase concurrency, the tree | latch is usually released when the | leaf page latch has been acquired. V Clustered index non-leaf | V Clustered index leaf | V Transaction system header | V Transaction undo mutex The undo log entry must be written | before any index page is modified. | Transaction undo mutex is for the undo | logs the analogue of the tree latch | for a B-tree. If a thread has the | trx undo mutex reserved, it is allowed | to latch the undo log pages in any | order, and also after it has acquired | the fsp latch. V Rollback segment mutex The rollback segment mutex must be | reserved, if, e.g., a new page must | be added to an undo log. The rollback | segment and the undo logs in its | history list can be seen as an | analogue of a B-tree, and the latches | reserved similarly, using a version of | lock-coupling. If an undo log must be | extended by a page when inserting an | undo log record, this corresponds to | a pessimistic insert in a B-tree. V Rollback segment header | V Purge system latch | V Undo log pages If a thread owns the trx undo mutex, | or for a log in the history list, the | rseg mutex, it is allowed to latch | undo log pages in any order, and even | after it has acquired the fsp latch. | If a thread does not have the | appropriate mutex, it is allowed to | latch only a single undo log page in | a mini-transaction. V File space management latch If a mini-transaction must allocate | several file pages, it can do that, | because it keeps the x-latch to the | file space management in its memo. V File system pages | V Kernel mutex If a kernel operation needs a file | page allocation, it must reserve the | fsp x-latch before acquiring the kernel | mutex. V Search system mutex | V Buffer pool mutex | V Log mutex | Any other latch | V Memory pool mutex */ /* Latching order levels */ /* User transaction locks are higher than any of the latch levels below: no latches are allowed when a thread goes to wait for a normal table or row lock! */ #define SYNC_USER_TRX_LOCK 9999 #define SYNC_NO_ORDER_CHECK 3000 /* this can be used to suppress latching order checking */ #define SYNC_LEVEL_VARYING 2000 /* Level is varying. Only used with buffer pool page locks, which do not have a fixed level, but instead have their level set after the page is locked; see e.g. ibuf_bitmap_get_map_page(). */ #define SYNC_DICT_OPERATION 1001 /* table create, drop, etc. reserve this in X-mode, implicit or backround operations purge, rollback, foreign key checks reserve this in S-mode */ #define SYNC_DICT 1000 #define SYNC_DICT_AUTOINC_MUTEX 999 #define SYNC_DICT_HEADER 995 #define SYNC_IBUF_HEADER 914 #define SYNC_IBUF_PESS_INSERT_MUTEX 912 #define SYNC_IBUF_MUTEX 910 /* ibuf mutex is really below SYNC_FSP_PAGE: we assign a value this high only to make the program to pass the debug checks */ /*-------------------------------*/ #define SYNC_INDEX_TREE 900 #define SYNC_TREE_NODE_NEW 892 #define SYNC_TREE_NODE_FROM_HASH 891 #define SYNC_TREE_NODE 890 #define SYNC_PURGE_SYS 810 #define SYNC_PURGE_LATCH 800 #define SYNC_TRX_UNDO 700 #define SYNC_RSEG 600 #define SYNC_RSEG_HEADER_NEW 591 #define SYNC_RSEG_HEADER 590 #define SYNC_TRX_UNDO_PAGE 570 #define SYNC_EXTERN_STORAGE 500 #define SYNC_FSP 400 #define SYNC_FSP_PAGE 395 /*------------------------------------- Insert buffer headers */ /*------------------------------------- ibuf_mutex */ /*------------------------------------- Insert buffer tree */ #define SYNC_IBUF_BITMAP_MUTEX 351 #define SYNC_IBUF_BITMAP 350 /*------------------------------------- MySQL query cache mutex */ /*------------------------------------- MySQL binlog mutex */ /*-------------------------------*/ #define SYNC_KERNEL 300 #define SYNC_REC_LOCK 299 #define SYNC_TRX_LOCK_HEAP 298 #define SYNC_TRX_SYS_HEADER 290 #define SYNC_LOG 170 #define SYNC_RECV 168 #define SYNC_WORK_QUEUE 161 #define SYNC_SEARCH_SYS 160 /* NOTE that if we have a memory heap that can be extended to the buffer pool, its logical level is SYNC_SEARCH_SYS, as memory allocation can call routines there! Otherwise the level is SYNC_MEM_HASH. */ #define SYNC_BUF_POOL 150 #define SYNC_BUF_BLOCK 149 #define SYNC_DOUBLEWRITE 140 #define SYNC_ANY_LATCH 135 #define SYNC_THR_LOCAL 133 #define SYNC_MEM_HASH 131 #define SYNC_MEM_POOL 130 /* Codes used to designate lock operations */ #define RW_LOCK_NOT_LOCKED 350 #define RW_LOCK_EX 351 #define RW_LOCK_EXCLUSIVE 351 #define RW_LOCK_SHARED 352 #define RW_LOCK_WAIT_EX 353 #define SYNC_MUTEX 354 /* NOTE! The structure appears here only for the compiler to know its size. Do not use its fields directly! The structure used in the spin lock implementation of a mutual exclusion semaphore. */ struct mutex_struct { ulint lock_word; /* This ulint is the target of the atomic test-and-set instruction in Win32 */ #if !defined(_WIN32) || !defined(UNIV_CAN_USE_X86_ASSEMBLER) os_fast_mutex_t os_fast_mutex; /* In other systems we use this OS mutex in place of lock_word */ #endif ulint waiters; /* This ulint is set to 1 if there are (or may be) threads waiting in the global wait array for this mutex to be released. Otherwise, this is 0. */ UT_LIST_NODE_T(mutex_t) list; /* All allocated mutexes are put into a list. Pointers to the next and prev. */ #ifdef UNIV_SYNC_DEBUG const char* file_name; /* File where the mutex was locked */ ulint line; /* Line where the mutex was locked */ ulint level; /* Level in the global latching order */ #endif /* UNIV_SYNC_DEBUG */ const char* cfile_name;/* File name where mutex created */ ulint cline; /* Line where created */ #ifdef UNIV_DEBUG os_thread_id_t thread_id; /* The thread id of the thread which locked the mutex. */ ulint magic_n; # define MUTEX_MAGIC_N (ulint)979585 #endif /* UNIV_DEBUG */ #ifndef UNIV_HOTBACKUP ulong count_os_wait; /* count of os_wait */ # ifdef UNIV_DEBUG ulong count_using; /* count of times mutex used */ ulong count_spin_loop; /* count of spin loops */ ulong count_spin_rounds; /* count of spin rounds */ ulong count_os_yield; /* count of os_wait */ uint64_t lspent_time; /* mutex os_wait timer msec */ uint64_t lmax_spent_time; /* mutex os_wait timer msec */ const char* cmutex_name;/* mutex name */ ulint mutex_type;/* 0 - usual mutex 1 - rw_lock mutex */ # endif /* UNIV_DEBUG */ #endif /* !UNIV_HOTBACKUP */ }; /* The global array of wait cells for implementation of the databases own mutexes and read-write locks. Appears here for debugging purposes only! */ extern sync_array_t* sync_primary_wait_array; /* Constant determining how long spin wait is continued before suspending the thread. A value 600 rounds on a 1995 100 MHz Pentium seems to correspond to 20 microseconds. */ #define SYNC_SPIN_ROUNDS srv_n_spin_wait_rounds /* The number of system calls made in this module. Intended for performance monitoring. */ extern ulint mutex_system_call_count; extern ulint mutex_exit_count; #ifdef UNIV_SYNC_DEBUG /* Latching order checks start when this is set TRUE */ extern ibool sync_order_checks_on; #endif /* UNIV_SYNC_DEBUG */ /* This variable is set to TRUE when sync_init is called */ extern ibool sync_initialized; /* Global list of database mutexes (not OS mutexes) created. */ typedef UT_LIST_BASE_NODE_T(mutex_t) ut_list_base_node_t; extern ut_list_base_node_t mutex_list; /* Mutex protecting the mutex_list variable */ extern mutex_t mutex_list_mutex; #ifndef UNIV_NONINL #include "sync0sync.ic" #endif #endif