MySQL 8.4.3
Source Code Documentation
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The read-write lock (for threads, not for database transactions) More...
#include <atomic>
#include <cstdint>
#include "univ.i"
#include "os0event.h"
#include "ut0counter.h"
#include "ut0mutex.h"
#include "sync0rw.ic"
Go to the source code of this file.
Classes | |
struct | rw_lock_debug_t |
The structure for storing debug info of an rw-lock. More... | |
struct | rw_lock_t |
The structure used in the spin lock implementation of a read-write lock. More... | |
Macros | |
#define | rw_lock_create(K, L, ID) pfs_rw_lock_create_func((K), (L), (ID), UT_LOCATION_HERE) |
Enumerations | |
enum | rw_lock_type_t { RW_S_LATCH = 1 , RW_X_LATCH = 2 , RW_SX_LATCH = 4 , RW_NO_LATCH = 8 } |
Functions | |
void | rw_lock_create_func (rw_lock_t *lock, latch_id_t id, ut::Location clocation) |
Creates, or rather, initializes an rw-lock object in a specified memory location (which must be appropriately aligned). More... | |
void | rw_lock_free_func (rw_lock_t *lock) |
Calling this function is obligatory only if the memory buffer containing the rw-lock is freed. More... | |
bool | rw_lock_validate (const rw_lock_t *lock) |
Checks that the rw-lock has been initialized and that there are no simultaneous shared and exclusive locks. More... | |
static bool | rw_lock_s_lock_low (rw_lock_t *lock, ulint pass, ut::Location location) |
Low-level function which tries to lock an rw-lock in s-mode. More... | |
static void | rw_lock_s_lock_func (rw_lock_t *lock, ulint pass, ut::Location location) |
NOTE! Use the corresponding macro, not directly this function, except if you supply the file name and line number. More... | |
static bool | rw_lock_x_lock_func_nowait (rw_lock_t *lock, ut::Location location) |
NOTE! Use the corresponding macro, not directly this function! Lock an rw-lock in exclusive mode for the current thread if the lock can be obtained immediately. More... | |
static void | rw_lock_s_unlock_func (ulint pass, rw_lock_t *lock) |
Releases a shared mode lock. More... | |
void | rw_lock_x_lock_func (rw_lock_t *lock, ulint pass, ut::Location location) |
NOTE! Use the corresponding macro, not directly this function! Lock an rw-lock in exclusive mode for the current thread. More... | |
bool | rw_lock_sx_lock_low (rw_lock_t *lock, ulint pass, ut::Location location) |
Low-level function for acquiring an sx lock. More... | |
void | rw_lock_sx_lock_func (rw_lock_t *lock, ulint pass, ut::Location location) |
NOTE! Use the corresponding macro, not directly this function! Lock an rw-lock in SX mode for the current thread. More... | |
static void | rw_lock_x_unlock_func (ulint pass, rw_lock_t *lock) |
Releases an exclusive mode lock. More... | |
static void | rw_lock_sx_unlock_func (ulint pass, rw_lock_t *lock) |
Releases an sx mode lock. More... | |
void | rw_lock_x_lock_move_ownership (rw_lock_t *lock) |
This function is used in the insert buffer to move the ownership of an x-latch on a buffer frame to the current thread. More... | |
static ulint | rw_lock_get_x_lock_count (const rw_lock_t *lock) |
Returns the value of writer_count for the lock. More... | |
static ulint | rw_lock_get_sx_lock_count (const rw_lock_t *lock) |
Returns the number of sx-lock for the lock. More... | |
static bool | rw_lock_get_waiters (const rw_lock_t *lock) |
Check if there are threads waiting for the rw-lock. More... | |
static ulint | rw_lock_get_writer (const rw_lock_t *lock) |
Returns the write-status of the lock - this function made more sense with the old rw_lock implementation. More... | |
static ulint | rw_lock_get_reader_count (const rw_lock_t *lock) |
Returns the number of readers (s-locks). More... | |
static bool | rw_lock_lock_word_decr (rw_lock_t *lock, ulint amount, lint threshold) |
Decrements lock_word the specified amount if it is greater than 0. More... | |
static lint | rw_lock_lock_word_incr (rw_lock_t *lock, ulint amount) |
Increments lock_word the specified amount and returns new value. More... | |
static void | rw_lock_set_writer_id_and_recursion_flag (rw_lock_t *lock, bool recursive) |
This function sets the lock->writer_thread and lock->recursive fields. More... | |
bool | rw_lock_own (const rw_lock_t *lock, ulint lock_type) |
Checks if the thread has locked the rw-lock in the specified mode, with the pass value == 0. More... | |
bool | rw_lock_own_flagged (const rw_lock_t *lock, rw_lock_flags_t flags) |
Checks if the thread has locked the rw-lock in the specified mode, with the pass value == 0. More... | |
bool | rw_lock_is_locked (rw_lock_t *lock, ulint lock_type) |
Checks if somebody has locked the rw-lock in the specified mode. More... | |
void | rw_lock_list_print_info (FILE *file) |
Prints debug info of currently locked rw-locks. More... | |
void | rw_lock_debug_print (FILE *f, const rw_lock_debug_t *info) |
Prints info of a debug struct. More... | |
static void | pfs_rw_lock_create_func (mysql_pfs_key_t key, rw_lock_t *lock, latch_id_t id, ut::Location clocation) |
Performance schema instrumented wrap function for rw_lock_create_func() NOTE! Please use the corresponding macro rw_lock_create(), not directly this function! More... | |
static void | pfs_rw_lock_x_lock_func (rw_lock_t *lock, ulint pass, ut::Location location) |
Performance schema instrumented wrap function for rw_lock_x_lock_func() NOTE! Please use the corresponding macro rw_lock_x_lock(), not directly this function! More... | |
static bool | pfs_rw_lock_x_lock_func_nowait (rw_lock_t *lock, ut::Location location) |
Performance schema instrumented wrap function for rw_lock_x_lock_func_nowait() NOTE! Please use the corresponding macro, not directly this function! More... | |
static void | pfs_rw_lock_s_lock_func (rw_lock_t *lock, ulint pass, ut::Location location) |
Performance schema instrumented wrap function for rw_lock_s_lock_func() NOTE! Please use the corresponding macro rw_lock_s_lock(), not directly this function! More... | |
static bool | pfs_rw_lock_s_lock_low (rw_lock_t *lock, ulint pass, ut::Location location) |
Performance schema instrumented wrap function for rw_lock_s_lock_func() NOTE! Please use the corresponding macro rw_lock_s_lock(), not directly this function! More... | |
static void | pfs_rw_lock_s_unlock_func (ulint pass, rw_lock_t *lock) |
Performance schema instrumented wrap function for rw_lock_s_unlock_func() NOTE! Please use the corresponding macro rw_lock_s_unlock(), not directly this function! More... | |
static void | pfs_rw_lock_x_unlock_func (ulint pass, rw_lock_t *lock) |
Performance schema instrumented wrap function for rw_lock_x_unlock_func() NOTE! Please use the corresponding macro rw_lock_x_unlock(), not directly this function! More... | |
static void | pfs_rw_lock_sx_lock_func (rw_lock_t *lock, ulint pass, ut::Location location) |
Performance schema instrumented wrap function for rw_lock_sx_lock_func() NOTE! Please use the corresponding macro rw_lock_sx_lock(), not directly this function! More... | |
static bool | pfs_rw_lock_sx_lock_low (rw_lock_t *lock, ulint pass, ut::Location location) |
Performance schema instrumented wrap function for rw_lock_sx_lock_nowait() NOTE! Please use the corresponding macro, not directly this function! More... | |
static void | pfs_rw_lock_sx_unlock_func (ulint pass, rw_lock_t *lock) |
Performance schema instrumented wrap function for rw_lock_sx_unlock_func() NOTE! Please use the corresponding macro rw_lock_sx_unlock(), not directly this function! More... | |
static void | pfs_rw_lock_free_func (rw_lock_t *lock) |
Performance schema instrumented wrap function for rw_lock_free_func() NOTE! Please use the corresponding macro rw_lock_free(), not directly this function! More... | |
static void | rw_lock_s_lock (rw_lock_t *M, ut::Location L) |
static void | rw_lock_s_lock_gen (rw_lock_t *M, ulint P, ut::Location L) |
static bool | rw_lock_s_lock_nowait (rw_lock_t *M, ut::Location L) |
static void | rw_lock_s_unlock_gen (rw_lock_t *L, ulint P) |
static void | rw_lock_sx_lock (rw_lock_t *M, ut::Location L) |
static void | rw_lock_sx_lock_gen (rw_lock_t *M, ulint P, ut::Location L) |
static bool | rw_lock_sx_lock_nowait (rw_lock_t *M, ulint P, ut::Location L) |
static void | rw_lock_sx_unlock (rw_lock_t *L) |
static void | rw_lock_sx_unlock_gen (rw_lock_t *L, ulint P) |
static void | rw_lock_x_lock (rw_lock_t *M, ut::Location L) |
static void | rw_lock_x_lock_gen (rw_lock_t *M, ulint P, ut::Location L) |
static bool | rw_lock_x_lock_nowait (rw_lock_t *M, ut::Location L) |
static void | rw_lock_x_unlock_gen (rw_lock_t *L, ulint P) |
static void | rw_lock_free (rw_lock_t *M) |
static void | rw_lock_s_unlock (rw_lock_t *L) |
static void | rw_lock_x_unlock (rw_lock_t *L) |
typedef | UT_LIST_BASE_NODE_T (rw_lock_t, list) rw_lock_list_t |
Variables | |
constexpr int32_t | X_LOCK_DECR = 0x20000000 |
constexpr int32_t | X_LOCK_HALF_DECR = 0x10000000 |
ib_mutex_t | rw_lock_list_mutex |
rw_lock_list_t | rw_lock_list |
The global list of rw-locks. More... | |
The read-write lock (for threads, not for database transactions)
Created 9/11/1995 Heikki Tuuri
#define rw_lock_create | ( | K, | |
L, | |||
ID | |||
) | pfs_rw_lock_create_func((K), (L), (ID), UT_LOCATION_HERE) |
enum rw_lock_type_t |
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inlinestatic |
Performance schema instrumented wrap function for rw_lock_create_func() NOTE! Please use the corresponding macro rw_lock_create(), not directly this function!
[in] | key | key registered with performance schema |
[in] | lock | rw lock |
[in] | id | latch_id |
[in] | clocation | location where created |
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inlinestatic |
Performance schema instrumented wrap function for rw_lock_free_func() NOTE! Please use the corresponding macro rw_lock_free(), not directly this function!
in: rw-lock
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inlinestatic |
Performance schema instrumented wrap function for rw_lock_s_lock_func() NOTE! Please use the corresponding macro rw_lock_s_lock(), not directly this function!
[in] | lock | pointer to rw-lock |
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in] | location | location where requested |
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inlinestatic |
Performance schema instrumented wrap function for rw_lock_s_lock_func() NOTE! Please use the corresponding macro rw_lock_s_lock(), not directly this function!
[in] | lock | pointer to rw-lock |
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in] | location | location where requested |
Performance schema instrumented wrap function for rw_lock_s_unlock_func() NOTE! Please use the corresponding macro rw_lock_s_unlock(), not directly this function!
[in] | pass | pass value; != 0, if the lock may have been passed to another thread to unlock |
[in,out] | lock | rw-lock |
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inlinestatic |
Performance schema instrumented wrap function for rw_lock_sx_lock_func() NOTE! Please use the corresponding macro rw_lock_sx_lock(), not directly this function!
[in] | lock | pointer to rw-lock |
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in] | location | location where requested |
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inlinestatic |
Performance schema instrumented wrap function for rw_lock_sx_lock_nowait() NOTE! Please use the corresponding macro, not directly this function!
[in] | lock | pointer to rw-lock |
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in] | location | location where requested |
Performance schema instrumented wrap function for rw_lock_sx_unlock_func() NOTE! Please use the corresponding macro rw_lock_sx_unlock(), not directly this function!
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in,out] | lock | pointer to rw-lock |
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inlinestatic |
Performance schema instrumented wrap function for rw_lock_x_lock_func() NOTE! Please use the corresponding macro rw_lock_x_lock(), not directly this function!
[in] | lock | pointer to rw-lock |
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in] | location | location where requested |
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inlinestatic |
Performance schema instrumented wrap function for rw_lock_x_lock_func_nowait() NOTE! Please use the corresponding macro, not directly this function!
[in] | lock | pointer to rw-lock |
[in] | location | location where requested |
Performance schema instrumented wrap function for rw_lock_x_unlock_func() NOTE! Please use the corresponding macro rw_lock_x_unlock(), not directly this function!
[in] | pass | pass value; != 0, if the lock may have been passed to another thread to unlock |
[in,out] | lock | rw-lock |
void rw_lock_create_func | ( | rw_lock_t * | lock, |
latch_id_t | id, | ||
ut::Location | clocation | ||
) |
Creates, or rather, initializes an rw-lock object in a specified memory location (which must be appropriately aligned).
The rw-lock is initialized to the non-locked state. Explicit freeing of the rw-lock with rw_lock_free is necessary only if the memory block containing it is freed.
[in] | lock | pointer to memory |
[in] | id | latch_id |
[in] | clocation | location where created |
void rw_lock_debug_print | ( | FILE * | f, |
const rw_lock_debug_t * | info | ||
) |
Prints info of a debug struct.
[in] | f | Output stream |
[in] | info | Debug struct |
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inlinestatic |
void rw_lock_free_func | ( | rw_lock_t * | lock | ) |
Calling this function is obligatory only if the memory buffer containing the rw-lock is freed.
Removes an rw-lock object from the global list. The rw-lock is checked to be in the non-locked state. in/out: rw-lock
Removes an rw-lock object from the global list. The rw-lock is checked to be in the non-locked state.
lock | in/out: rw-lock |
Returns the number of readers (s-locks).
[in] | lock | rw-lock |
Returns the number of sx-lock for the lock.
Does not reserve the lock mutex, so the caller must be sure it is not changed during the call.
[in] | lock | rw-lock |
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inlinestatic |
Check if there are threads waiting for the rw-lock.
[in] | lock | rw-lock |
Returns the write-status of the lock - this function made more sense with the old rw_lock implementation.
[in] | lock | rw-lock |
Returns the value of writer_count for the lock.
Does not reserve the lock mutex, so the caller must be sure it is not changed during the call.
[in] | lock | rw-lock |
Checks if somebody has locked the rw-lock in the specified mode.
[in] | lock | the rw-lock |
[in] | lock_type | The exact lock type to check: RW_LOCK_S, RW_LOCK_SX or RW_LOCK_X |
lock | in: rw-lock |
lock_type | in: lock type: RW_LOCK_S, RW_LOCK_X or RW_LOCK_SX |
void rw_lock_list_print_info | ( | FILE * | file | ) |
Prints debug info of currently locked rw-locks.
[in] | file | file where to print |
file | in: file where to print |
Decrements lock_word the specified amount if it is greater than 0.
This is used by both s_lock and x_lock operations.
[in,out] | lock | rw-lock |
[in] | amount | amount to decrement |
[in] | threshold | threshold of judgement |
Decrements lock_word the specified amount if it is greater than 0.
This does does not support recursive x-locks: they should be handled by the caller and need not be atomic since they are performed by the current lock holder. Returns true if the decrement was made, false if not.
lock | in/out: rw-lock |
amount | in: amount to decrement |
threshold | in: threshold of judgement |
Increments lock_word the specified amount and returns new value.
[in,out] | lock | rw-lock |
[in] | amount | amount to decrement |
Checks if the thread has locked the rw-lock in the specified mode, with the pass value == 0.
Note that the mode is checked exactly, so if the thread owns RW_LOCK_X only, the rw_lock_own(..,RW_LOCK_S) will return false.
[in] | lock | the rw-lock |
[in] | lock_type | The exact lock type to check: RW_LOCK_S, RW_LOCK_SX or RW_LOCK_X |
bool rw_lock_own_flagged | ( | const rw_lock_t * | lock, |
rw_lock_flags_t | flags | ||
) |
Checks if the thread has locked the rw-lock in the specified mode, with the pass value == 0.
[in] | lock | rw-lock |
[in] | flags | specify lock types with OR of the rw_lock_flag_t values |
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inlinestatic |
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inlinestatic |
NOTE! Use the corresponding macro, not directly this function, except if you supply the file name and line number.
Lock an rw-lock in shared mode for the current thread. If the rw-lock is locked in exclusive mode, or there is an exclusive lock request waiting, the function spins a preset time (controlled by srv_n_spin_wait_rounds), waiting for the lock, before suspending the thread.
[in] | lock | pointer to rw-lock |
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in] | location | location where requested |
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inlinestatic |
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inlinestatic |
Low-level function which tries to lock an rw-lock in s-mode.
Performs no spinning.
[in] | lock | pointer to rw-lock |
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in] | location | location where requested |
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inlinestatic |
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inlinestatic |
Releases a shared mode lock.
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in,out] | lock | rw-lock |
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inlinestatic |
This function sets the lock->writer_thread and lock->recursive fields.
Sets lock->recursive field using atomic release after setting lock->writer thread to ensure proper memory ordering of the two. Note that it is assumed that the caller of this function effectively owns the lock i.e.: nobody else is allowed to modify lock->writer_thread at this point in time. The protocol is that lock->writer_thread MUST be updated BEFORE the lock->recursive flag is set.
[in,out] | lock | lock to work on |
[in] | recursive | true if recursion allowed |
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inlinestatic |
void rw_lock_sx_lock_func | ( | rw_lock_t * | lock, |
ulint | pass, | ||
ut::Location | location | ||
) |
NOTE! Use the corresponding macro, not directly this function! Lock an rw-lock in SX mode for the current thread.
If the rw-lock is locked in exclusive mode, or there is an exclusive lock request waiting, the function spins a preset time (controlled by SYNC_SPIN_ROUNDS), waiting for the lock, before suspending the thread. If the same thread has an x-lock on the rw-lock, locking succeed, with the following exception: if pass != 0, only a single sx-lock may be taken on the lock. NOTE: If the same thread has an s-lock, locking does not succeed!
[in] | lock | pointer to rw-lock |
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in] | location | location where requested |
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inlinestatic |
bool rw_lock_sx_lock_low | ( | rw_lock_t * | lock, |
ulint | pass, | ||
ut::Location | location | ||
) |
Low-level function for acquiring an sx lock.
[in] | lock | pointer to rw-lock |
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in] | location | location where requested |
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inlinestatic |
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inlinestatic |
Releases an sx mode lock.
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in,out] | lock | rw-lock |
bool rw_lock_validate | ( | const rw_lock_t * | lock | ) |
Checks that the rw-lock has been initialized and that there are no simultaneous shared and exclusive locks.
lock | in: rw-lock |
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inlinestatic |
void rw_lock_x_lock_func | ( | rw_lock_t * | lock, |
ulint | pass, | ||
ut::Location | location | ||
) |
NOTE! Use the corresponding macro, not directly this function! Lock an rw-lock in exclusive mode for the current thread.
If the rw-lock is locked in shared or exclusive mode, or there is an exclusive lock request waiting, the function spins a preset time (controlled by srv_n_spin_wait_rounds), waiting for the lock, before suspending the thread. If the same thread has an x-lock on the rw-lock, locking succeed, with the following exception: if pass != 0, only a single x-lock may be taken on the lock. NOTE: If the same thread has an s-lock, locking does not succeed!
[in] | lock | pointer to rw-lock |
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in] | location | location where requested |
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inlinestatic |
NOTE! Use the corresponding macro, not directly this function! Lock an rw-lock in exclusive mode for the current thread if the lock can be obtained immediately.
[in] | lock | pointer to rw-lock |
[in] | location | location where requested |
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inlinestatic |
void rw_lock_x_lock_move_ownership | ( | rw_lock_t * | lock | ) |
This function is used in the insert buffer to move the ownership of an x-latch on a buffer frame to the current thread.
The x-latch was set by the buffer read operation and it protected the buffer frame while the read was done. The ownership is moved because we want that the current thread is able to acquire a second x-latch which is stored in an mtr. This, in turn, is needed to pass the debug checks of index page operations.
[in] | lock | lock which was x-locked in the buffer read. |
The x-latch was set by the buffer read operation and it protected the buffer frame while the read was done. The ownership is moved because we want that the current thread is able to acquire a second x-latch which is stored in an mtr. This, in turn, is needed to pass the debug checks of index page operations.
lock | in: lock which was x-locked in the buffer read |
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inlinestatic |
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inlinestatic |
Releases an exclusive mode lock.
[in] | pass | pass value; != 0, if the lock will be passed to another thread to unlock |
[in,out] | lock | rw-lock |
typedef UT_LIST_BASE_NODE_T | ( | rw_lock_t | , |
list | |||
) |
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extern |
The global list of rw-locks.
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extern |
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constexpr |
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constexpr |