Debug checks for latches. More...

#include "sync0debug.h"
#include <stddef.h>
#include <algorithm>
#include <atomic>
#include <iostream>
#include <map>
#include <string>
#include <vector>
#include "sync0rw.h"
#include "ut0mutex.h"
#include <scope_guard.h>
#include "srv0start.h"
#include "ut0new.h"
#include <current_thd.h>

Classes
struct	Latched
	The latch held by a thread. More...

struct	LatchDebug
	The deadlock detector. More...

struct	LatchDebug::latch_level_less
	Comparator for the Levels . More...

struct	CreateTracker
	Track mutex file creation name and line number. More...

struct	CreateTracker::File
	For tracking the filename and line number. More...

Macros
#define	LEVEL_MAP_INSERT(T)

Typedefs
typedef std::vector< Latched, ut::allocator< Latched > >	Latches
	Thread specific latches. More...

Functions
void	sync_check_lock_validate (const latch_t *latch)
	Check if it is OK to acquire the latch. More...

void	sync_check_lock_granted (const latch_t *latch)
	Note that the lock has been granted. More...

void	sync_check_lock (const latch_t *latch, latch_level_t level)
	Check if it is OK to acquire the latch. More...

void	sync_check_relock (const latch_t *latch)
	Check if it is OK to re-acquire the lock. More...

void	sync_check_unlock (const latch_t *latch)
	Removes a latch from the thread level array if it is found there. More...

const latch_t *	sync_check_find (latch_level_t level)
	Checks if the level array for the current thread contains a mutex or rw-latch at the specified level. More...

bool	sync_check_iterate (sync_check_functor_t &functor)
	Checks that the level array for the current thread is empty. More...

void	sync_check_enable ()
	Enable sync order checking. More...

void	rw_lock_debug_mutex_enter ()
	Acquires the debug mutex. More...

void	rw_lock_debug_mutex_exit ()
	Releases the debug mutex. More...

static void	sync_latch_meta_init () 1
	Load the latch meta data. More...

static void	sync_latch_meta_destroy ()
	Destroy the latch meta data. More...

void	sync_file_created_register (const void ptr, const char filename, uint16_t line)
	Register a latch, called when it is created. More...

void	sync_file_created_deregister (const void *ptr)
	Deregister a latch, called when it is destroyed. More...

std::string	sync_file_created_get (const void *ptr)
	Get the string where the file was created. More...

void	sync_check_init (size_t max_threads)
	Initializes the synchronization data structures. More...

void	sync_check_close ()
	Frees the resources in InnoDB's own synchronization data structures. More...

Variables
bool	srv_sync_debug

static ib_mutex_t	rw_lock_debug_mutex
	The global mutex which protects debug info lists of all rw-locks. More...

static os_event_t	rw_lock_debug_event
	If deadlock detection does not get immediately the mutex, it may wait for this event. More...

static std::atomic< bool >	rw_lock_debug_waiters {false}
	This is set to true, if there may be waiters for the event. More...

LatchMetaData	latch_meta
	Note: This is accessed without any mutex protection. More...

static CreateTracker *	create_tracker
	Track latch creation location. More...

Detailed Description

Debug checks for latches.

Created 2012-08-21 Sunny Bains

Macro Definition Documentation

◆ LEVEL_MAP_INSERT

#define LEVEL_MAP_INSERT ( T )

Value:

  do {                                              \
    std::pair<Levels::iterator, bool> result =      \
        m_levels.insert(Levels::value_type(T, #T)); \
    ut_ad(result.second);                           \
  } while (0)

Typedef Documentation

◆ Latches

typedef std::vector<Latched, ut::allocator<Latched> > Latches

Thread specific latches.

This is ordered on level in descending order.

Function Documentation

◆ rw_lock_debug_mutex_enter()

void rw_lock_debug_mutex_enter ( )

Acquires the debug mutex.

We cannot use the mutex defined in sync0sync, because the debug mutex is also acquired in sync0arr while holding the OS mutex protecting the sync array, and the ordinary mutex_enter might recursively call routines in sync0arr, leading to a deadlock on the OS mutex.

◆ rw_lock_debug_mutex_exit()

void rw_lock_debug_mutex_exit ( )

Releases the debug mutex.

◆ sync_check_close()

void sync_check_close ( )

Frees the resources in InnoDB's own synchronization data structures.

Frees the resources in synchronization data structures.

Use os_sync_free() after calling this.

◆ sync_check_enable()

void sync_check_enable ( )

Enable sync order checking.

Note: We don't enforce any synchronisation checks. The caller must ensure that no races can occur

◆ sync_check_find()

const latch_t * sync_check_find ( latch_level_t level )

Checks if the level array for the current thread contains a mutex or rw-latch at the specified level.

Parameters

[in] level to find

Returns: a matching latch, or NULL if not found

◆ sync_check_init()

void sync_check_init ( size_t max_threads )

Initializes the synchronization data structures.

Parameters

[in] max_threads Maximum threads that can be created.

For collecting latch statistic - SHOW ... MUTEX

For trcking mutex creation location

◆ sync_check_iterate()

bool sync_check_iterate ( sync_check_functor_t & functor )

Checks that the level array for the current thread is empty.

Terminate iteration if the functor returns true.

Parameters

[in,out] functor called for each element.

Returns: true if the functor returns true

◆ sync_check_lock()

void sync_check_lock	(	const latch_t *	latch,
		latch_level_t	level
	)

Check if it is OK to acquire the latch.

Parameters

[in]	latch	latch type
[in]	level	the level of the mutex

◆ sync_check_lock_granted()

void sync_check_lock_granted ( const latch_t * latch )

Note that the lock has been granted.

Parameters

[in] latch latch type

◆ sync_check_lock_validate()

void sync_check_lock_validate ( const latch_t * latch )

Check if it is OK to acquire the latch.

Parameters

[in] latch latch type

◆ sync_check_relock()

void sync_check_relock ( const latch_t * latch )

Check if it is OK to re-acquire the lock.

Parameters

[in] latch RW-LOCK to relock (recursive X locks)

◆ sync_check_unlock()

void sync_check_unlock ( const latch_t * latch )

Removes a latch from the thread level array if it is found there.

Parameters

[in] latch The latch to unlock

◆ sync_file_created_deregister()

void sync_file_created_deregister ( const void * ptr )

Deregister a latch, called when it is destroyed.

Parameters

[in] ptr Latch to be destroyed

◆ sync_file_created_get()

std::string sync_file_created_get ( const void * ptr )

Get the string where the file was created.

Its format is "name:line"

Parameters

[in] ptr Latch instance

Returns: created information or "" if can't be found

◆ sync_file_created_register()

void sync_file_created_register	(	const void *	ptr,
		const char *	filename,
		uint16_t	line
	)

Register a latch, called when it is created.

Parameters

[in]	ptr	Latch instance that was created
[in]	filename	Filename where it was created
[in]	line	Line number in filename

◆ sync_latch_meta_destroy()

static void sync_latch_meta_destroy ( )

static

Destroy the latch meta data.

◆ sync_latch_meta_init()

static void sync_latch_meta_init ( )

static

Load the latch meta data.

Variable Documentation

◆ create_tracker

CreateTracker* create_tracker

static

Track latch creation location.

For reducing the size of the latches

◆ latch_meta

LatchMetaData latch_meta

Note: This is accessed without any mutex protection.

It is initialised at startup and elements should not be added to or removed from it after that. See sync_latch_meta_init()

◆ rw_lock_debug_event

os_event_t rw_lock_debug_event

static

If deadlock detection does not get immediately the mutex, it may wait for this event.

◆ rw_lock_debug_mutex

ib_mutex_t rw_lock_debug_mutex

static

The global mutex which protects debug info lists of all rw-locks.

To modify the debug info list of an rw-lock, this mutex has to be acquired in addition to the mutex protecting the lock.

◆ rw_lock_debug_waiters

std::atomic<bool> rw_lock_debug_waiters {false}

static

This is set to true, if there may be waiters for the event.

◆ srv_sync_debug

bool srv_sync_debug

Classes

Macros

Typedefs

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ LEVEL_MAP_INSERT

Typedef Documentation

◆ Latches

Function Documentation

◆ rw_lock_debug_mutex_enter()

◆ rw_lock_debug_mutex_exit()

◆ sync_check_close()

◆ sync_check_enable()

◆ sync_check_find()

◆ sync_check_init()

◆ sync_check_iterate()

◆ sync_check_lock()

◆ sync_check_lock_granted()

◆ sync_check_lock_validate()

◆ sync_check_relock()

◆ sync_check_unlock()

◆ sync_file_created_deregister()

◆ sync_file_created_get()

◆ sync_file_created_register()

◆ sync_latch_meta_destroy()

◆ sync_latch_meta_init()

Variable Documentation

◆ create_tracker

◆ latch_meta

◆ rw_lock_debug_event

◆ rw_lock_debug_mutex

◆ rw_lock_debug_waiters

◆ srv_sync_debug