TwoQPage Class Reference

Inheritance diagram for TwoQPage:

List of all members.

Public Types
enum	DataStatus {   DATA_INVALID, DATA_ERROR, DATA_CLEAN, DATA_DIRTY,   DATA_WRITE, DATA_READ }
	Enumeration of possible status of page data. More...
enum	PageState { PAGE_STATE_POPULAR_PINNED, PAGE_STATE_POPULAR_UNPINNED, PAGE_STATE_FRESHMAN, PAGE_STATE_FREE }
	Enumeration of possible state values for a page when used with TwoQVictimPolicy. More...
Public Member Functions
	TwoQPage (Cache &cache, PBuffer buffer)
Cache &	getCache ()
	Returns: the cache which manages this page
bool	isDirty () const
	Returns: are the in-memory page contents different from those in the corresponding block on disk?
bool	isTransferInProgress () const
	Returns: is I/O currently in progress on this page?
bool	isDataValid () const
	Returns: is the page data valid?
bool	isDataError () const
	Returns: did the read required for mapping fail?
BlockId	getBlockId () const
	Returns: the mapped BlockId
PConstBuffer	getReadableData () const
	Obtains a const pointer to the page contents.
PBuffer	getWritableData ()
	Obtains a writable pointer to the page contents, marking the page dirty.
bool	isScratchLocked () const
	Returns: true if page is currently locked as scratch memory
MappedPageListener *	getMappedPageListener () const
	Returns: the MappedPageListener associated with this page
bool	tryUpgrade (TxnId txnId)
	Attempts to upgrade from LOCKMODE_S (which caller must already have acquired) to LOCKMODE_X.
void	upgrade (TxnId txnId)
	Upgrades from LOCKMODE_S (which caller must already have acquired) to LOCKMODE_X.
void	swapBuffers (CachePage &other)
	Swaps this page's buffer with another page.
PageState	getState ()
	Returns: state of a page
void	setState (PageState newState)
	Sets a page's state.
TwoQDirtyPage &	getDirtyPageNode ()
	Returns: the dirty node corresponding to the page
IntrusiveDListNode *	getNext () const
IntrusiveDListNode *	getPrev () const
void	detach ()
void	insertBefore (IntrusiveDListNode &newNext)
void	insertAfter (IntrusiveDListNode &newPrev)

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Detailed Description

Definition at line 42 of file Cache.cpp.

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Member Enumeration Documentation

enum CachePage::DataStatus [inherited]

Enumeration of possible status of page data.

Order matters (valid data states are grouped together, as are I/O states).

Enumerator:

DATA_INVALID	The page contents are invalid (either unmapped or newly allocated).
DATA_ERROR	The last transfer failed (so the page contents are invalid).
DATA_CLEAN	No transfer is in progress, and the page contains valid, unmodified data.
DATA_DIRTY	No transfer is in progress, and the page contains valid, dirty data.
DATA_WRITE	A disk write is in progress (so the page contains valid data).
DATA_READ	A disk read is in progress (so the page does not yet contain valid data).

Definition at line 64 of file CachePage.h.

                    {
        DATA_INVALID,

        DATA_ERROR,

        DATA_CLEAN,

        DATA_DIRTY,

        DATA_WRITE,

        DATA_READ
    };

enum TwoQVictim::PageState [inherited]

Enumeration of possible state values for a page when used with TwoQVictimPolicy.

Enumerator:

PAGE_STATE_POPULAR_PINNED	Page is in the popular-pinned queue.
PAGE_STATE_POPULAR_UNPINNED	Page is in the popular-unpinned queue.
PAGE_STATE_FRESHMAN	Page is in the freshmen queue.
PAGE_STATE_FREE	Page is not currently in the cache.

Definition at line 294 of file TwoQVictimPolicy.h.

                   {
        PAGE_STATE_POPULAR_PINNED,
        PAGE_STATE_POPULAR_UNPINNED,
        PAGE_STATE_FRESHMAN,
        PAGE_STATE_FREE
    };

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Constructor & Destructor Documentation

TwoQPage::TwoQPage	(	Cache &	cache,
		PBuffer	buffer
	)			[inline]

Definition at line 45 of file Cache.cpp.

        : CachePage(cache,buffer)
    {
    }

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Member Function Documentation

Cache& CachePage::getCache

(

)

[inline, inherited]

Returns:

the cache which manages this page

Definition at line 206 of file CachePage.h.

Referenced by DoubleBufferExecStream::execute(), CachePage::notifyTransferCompletion(), FlatFileExecStreamImpl::open(), ScratchBufferExecStream::open(), and DoubleBufferExecStream::open().

    {
        return cache;
    }

bool CachePage::isDirty

(

)

const [inline, inherited]

Returns:

are the in-memory page contents different from those in the corresponding block on disk?

Definition at line 215 of file CachePage.h.

Referenced by WALSegment::notifyPageUnmap(), and FuzzyCheckpointSet::operator()().

    {
        return dataStatus == DATA_DIRTY;
    }

bool CachePage::isTransferInProgress

(

)

const [inline, inherited]

Returns:

is I/O currently in progress on this page?

Definition at line 223 of file CachePage.h.

    {
        return (dataStatus >= DATA_WRITE);
    }

bool CachePage::isDataValid

(

)

const [inline, inherited]

Returns:

is the page data valid?

Definition at line 231 of file CachePage.h.

Referenced by CrcSegInputStream::lockBufferParanoid(), and CacheImpl< PageT, VictimPolicyT >::markPageDirty().

    {
        return (dataStatus >= DATA_CLEAN) && (dataStatus <= DATA_WRITE);
    }

bool CachePage::isDataError

(

)

const [inline, inherited]

Returns:

did the read required for mapping fail?

Definition at line 239 of file CachePage.h.

    {
        return (dataStatus == DATA_ERROR);
    }

BlockId CachePage::getBlockId

(

)

const [inline, inherited]

Returns:

the mapped BlockId

Definition at line 247 of file CachePage.h.

Referenced by VersionedSegment::canFlushPage(), CachePage::isScratchLocked(), TracingSegment::notifyAfterPageCheckpointFlush(), WALSegment::notifyAfterPageFlush(), TracingSegment::notifyAfterPageFlush(), TracingSegment::notifyAfterPageRead(), TracingSegment::notifyBeforePageFlush(), WALSegment::notifyPageDirty(), VersionedSegment::notifyPageDirty(), TracingSegment::notifyPageDirty(), TracingSegment::notifyPageMap(), TracingSegment::notifyPageUnmap(), CacheImpl< PageT, VictimPolicyT >::notifyTransferCompletion(), and DeviceIdPagePredicate::operator()().

    {
        return blockId;
    }

PConstBuffer CachePage::getReadableData

(

)

const [inline, inherited]

Obtains a const pointer to the page contents.

The page must be locked in shared or exclusive mode first. The number of valid bytes returned depends on the page size.

Returns:

pointer to the page contents (const to prevent accidental modification)

Definition at line 260 of file CachePage.h.

References LOCKMODE_S.

Referenced by VersionedRandomAllocationSegment::backupAllocationNodes(), SegNodeLock< Node >::checkMagicNumber(), SpillOutputStream::getInputStream(), SegNodeLock< Node >::getNodeForRead(), Segment::getReadableFooter(), SegNodeLock< Node >::isMagicNumberValid(), VersionedRandomAllocationSegment::locateDataPages(), VersionedSegment::notifyPageDirty(), SpillOutputStream::spill(), and PagingTestBase::verifyPage().

    {
        assert(isDataValid());
        assert(lock.isLocked(LOCKMODE_S) || isExclusiveLockHeld());
        return pBuffer;
    }

PBuffer CachePage::getWritableData

(

)

[inline, inherited]

Obtains a writable pointer to the page contents, marking the page dirty.

The page must be locked in exclusive mode first. The number of valid bytes returned depends on the page size.

Returns:

pointer to the page contents

Definition at line 274 of file CachePage.h.

References Cache::getCache().

Referenced by LcsClusterNodeWriter::allocArrays(), LbmEntryTest::allocateBuf(), ExternalSortRunLoader::allocateBuffer(), BTreePrefetchSearchExecStream::allocateScratchPages(), LhxHashTable::allocBlock(), DoubleBufferExecStream::execute(), PagingTestBase::fillPage(), SegNodeLock< Node >::getNodeForWrite(), Segment::getWritableFooter(), LbmGeneratorExecStream::initBitmapTable(), LcsClusterAppendExecStream::initLoad(), SegPageBackupRestoreDevice::initScratchPages(), VersionedSegment::notifyPageDirty(), LbmUnionExecStream::open(), LbmChopperExecStream::open(), FlatFileExecStreamImpl::open(), ScratchBufferExecStream::open(), DoubleBufferExecStream::open(), VersionedSegment::recover(), SpillOutputStream::SpillOutputStream(), SegPageLock::swapBuffers(), and RandomAllocationSegmentTest::testAllocateAndDeallocate().

    {
        assert(isExclusiveLockHeld());
        assert(!isDataError());
        assert(!isTransferInProgress());
        // REVIEW:  is thread-safety ever an issue here?  If so, it's also an
        // issue for the previous assertions.
        if (!isDirty()) {
            getCache().markPageDirty(*this);
        }
        return pBuffer;
    }

bool CachePage::isScratchLocked

(

)

const [inherited]

Returns:

true if page is currently locked as scratch memory

Definition at line 72 of file CachePage.cpp.

References CachePage::getBlockId(), CompoundId::getDeviceId(), and Cache::NULL_DEVICE_ID.

{
    return CompoundId::getDeviceId(getBlockId()) == Cache::NULL_DEVICE_ID;
}

MappedPageListener* CachePage::getMappedPageListener

(

)

const [inline, inherited]

Returns:

the MappedPageListener associated with this page

Definition at line 295 of file CachePage.h.

Referenced by MappedPageListenerPredicate::operator()().

    {
        assert(hasBlockId());
        return pMappedPageListener;
    }

bool CachePage::tryUpgrade

(

TxnId

txnId

)

[inline, inherited]

Attempts to upgrade from LOCKMODE_S (which caller must already have acquired) to LOCKMODE_X.

This is a NOWAIT operation; it fails immediately if any other thread already holds a lock on the same page, or when a transfer is already in progress.

Returns:

true if upgrade succeeded

Definition at line 309 of file CachePage.h.

References CacheImpl< PageT, VictimPolicyT >::getAllocator(), Cache::getCache(), and Cache::getPageSize().

    {
        StrictMutexGuard pageGuard(mutex);
        if (isTransferInProgress()) {
            return false;
        }
#ifdef DEBUG
        int errorCode;
        if (getCache().getAllocator().setProtection(
                pBuffer, getCache().getPageSize(), false, &errorCode))
        {
            throw SysCallExcn("memory protection failed", errorCode);
        }
#endif
        return lock.tryUpgrade(txnId);
    }

void CachePage::upgrade

(

TxnId

txnId

)

[inline, inherited]

Upgrades from LOCKMODE_S (which caller must already have acquired) to LOCKMODE_X.

This is a WAIT operation if a page transfer is in progress. It's assumed that there are no other threads holding a lock on the same page.

Definition at line 332 of file CachePage.h.

References CacheImpl< PageT, VictimPolicyT >::getAllocator(), Cache::getCache(), and Cache::getPageSize().

    {
        StrictMutexGuard pageGuard(mutex);
        while (isTransferInProgress()) {
            waitForPendingIO(pageGuard);
        }
#ifdef DEBUG
        int errorCode;
        if (getCache().getAllocator().setProtection(
                pBuffer, getCache().getPageSize(), false, &errorCode))
        {
            throw SysCallExcn("memory protection failed", errorCode);
        }
#endif
        bool rc = lock.tryUpgrade(txnId);
        assert(rc);
    }

void CachePage::swapBuffers

(

CachePage &

other

)

[inherited]

Swaps this page's buffer with another page.

You almost certainly shouldn't be calling this directly (see SegPageLock::swapBuffers).

Parameters:

other

page to swap with

Definition at line 65 of file CachePage.cpp.

References CachePage::isExclusiveLockHeld(), and CachePage::pBuffer.

{
    assert(isExclusiveLockHeld());
    assert(other.isExclusiveLockHeld());
    std::swap(pBuffer,other.pBuffer);
}

PageState TwoQVictim::getState

(

)

[inline, inherited]

Returns:

state of a page

Definition at line 335 of file TwoQVictimPolicy.h.

    {
        return state;
    }

void TwoQVictim::setState

(

PageState

newState

)

[inline, inherited]

Sets a page's state.

Parameters:

newState

the new state value for a page

Definition at line 345 of file TwoQVictimPolicy.h.

    {
        state = newState;
    }

TwoQDirtyPage& TwoQVictim::getDirtyPageNode

(

)

[inline, inherited]

Returns:

the dirty node corresponding to the page

Definition at line 353 of file TwoQVictimPolicy.h.

    {
        return dirtyPageNode;
    }

IntrusiveDListNode* IntrusiveDListNode::getNext

(

)

const [inline, inherited]

Definition at line 45 of file IntrusiveDList.h.

Referenced by TwoQPageQueue::moveToTail(), TwoQPageQueue::remove(), and TwoQPageQueue::validateQueue().

    {
        return pNext;
    }

IntrusiveDListNode* IntrusiveDListNode::getPrev

(

)

const [inline, inherited]

Definition at line 50 of file IntrusiveDList.h.

Referenced by TwoQPageQueue::moveToHead(), TwoQPageQueue::remove(), and TwoQPageQueue::validateQueue().

    {
        return pPrev;
    }

void IntrusiveDListNode::detach

(

)

[inline, inherited]

Definition at line 55 of file IntrusiveDList.h.

Referenced by TwoQPageQueue::moveToHead(), TwoQPageQueue::moveToTail(), and TwoQPageQueue::remove().

    {
        if (pNext) {
            pNext->pPrev = pPrev;
        }
        if (pPrev) {
            pPrev->pNext = pNext;
        }
        pPrev = pNext = NULL;
    }

void IntrusiveDListNode::insertBefore

(

IntrusiveDListNode &

newNext

)

[inline, inherited]

Definition at line 66 of file IntrusiveDList.h.

References IntrusiveDListNode::pNext, and IntrusiveDListNode::pPrev.

Referenced by TwoQPageQueue::insertAtHead(), and TwoQPageQueue::moveToHead().

    {
        pNext = &newNext;
        pPrev = pNext->pPrev;
        pNext->pPrev = this;
        if (pPrev) {
            pPrev->pNext = this;
        }
    }

void IntrusiveDListNode::insertAfter

(

IntrusiveDListNode &

newPrev

)

[inline, inherited]

Definition at line 76 of file IntrusiveDList.h.

References IntrusiveDListNode::pNext, and IntrusiveDListNode::pPrev.

Referenced by TwoQPageQueue::insertAtTail(), and TwoQPageQueue::moveToTail().

    {
        pPrev = &newPrev;
        pNext = pPrev->pNext;
        pPrev->pNext = this;
        if (pNext) {
            pNext->pPrev = this;
        }
    }

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

• /home/pub/open/dev/fennel/cache/Cache.cpp

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