HazardPointer Class Reference

A "Hazard Pointer" class used to iterate over page lists inside the buffer pool. More...

#include <buf0buf.h>

Inheritance diagram for HazardPointer:

Public Member Functions
	HazardPointer (const buf_pool_t *buf_pool, const ib_mutex_t *mutex)
	Constructor. More...
virtual	~HazardPointer ()=default
	Destructor. More...
buf_page_t *	get () const
	Get current value. More...
void	set (buf_page_t *bpage)
	Set current value. More...
bool	is_hp (const buf_page_t *bpage)
	Checks if a bpage is the hp. More...
virtual void	adjust (const buf_page_t *bpage)=0
	Adjust the value of hp. More...
void	move (const buf_page_t *bpage, buf_page_t *dpage)
	Adjust the value of hp for moving. More...

Protected Member Functions
	HazardPointer (const HazardPointer &)
	Disable copying. More...
HazardPointer &	operator= (const HazardPointer &)

Protected Attributes
const buf_pool_t *	m_buf_pool
	Buffer pool instance. More...
const ib_mutex_t *	m_mutex
	mutex that protects access to the m_hp. More...
buf_page_t *	m_hp
	hazard pointer. More...

Detailed Description

A "Hazard Pointer" class used to iterate over page lists inside the buffer pool.

A hazard pointer is a buf_page_t pointer which we intend to iterate over next and we want it remain valid even after we release the buffer pool mutex.

Constructor & Destructor Documentation

HazardPointer() [1/2]

HazardPointer::HazardPointer ( const buf_pool_t *  buf_pool, const ib_mutex_t *  mutex  )

inline

Constructor.

Parameters

buf_pool	buffer pool instance
mutex	mutex that is protecting the hp.

~HazardPointer()

virtual HazardPointer::~HazardPointer ( )

virtualdefault

Destructor.

HazardPointer() [2/2]

HazardPointer::HazardPointer ( const HazardPointer &  )

protected

Disable copying.

Member Function Documentation

adjust()

virtual void HazardPointer::adjust ( const buf_page_t *  bpage )

pure virtual

Adjust the value of hp.

This happens when some other thread working on the same list attempts to remove the hp from the list. Must be implemented by the derived classes.

Parameters

bpage

buffer block to be compared

Implemented in FlushHp, and LRUHp.

get()

buf_page_t * HazardPointer::get ( ) const

inline

Get current value.

is_hp()

bool HazardPointer::is_hp

(

const buf_page_t *

bpage

)

Checks if a bpage is the hp.

Parameters

bpage

buffer block to be compared

Returns

true if it is hp

move()

void HazardPointer::move	(	const buf_page_t *	bpage,
		buf_page_t *	dpage
	)

Adjust the value of hp for moving.

This happens when some other thread working on the same list attempts to relocate the hp of the page.

Parameters

bpage	buffer block to be compared
dpage	buffer block to be moved to

operator=()

HazardPointer & HazardPointer::operator= ( const HazardPointer &  )

protected

set()

void HazardPointer::set

(

buf_page_t *

bpage

)

Set current value.

Parameters

bpage

buffer block to be set as hp

Member Data Documentation

m_buf_pool

const buf_pool_t* HazardPointer::m_buf_pool

protected

Buffer pool instance.

m_hp

buf_page_t* HazardPointer::m_hp

protected

hazard pointer.

m_mutex

const ib_mutex_t* HazardPointer::m_mutex

protected

mutex that protects access to the m_hp.

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The documentation for this class was generated from the following files:

• storage/innobase/include/buf0buf.h
• storage/innobase/buf/buf0buf.cc