Package org.apache.ignite.internal.pagemem

Class PagePool

java.lang.Object

org.apache.ignite.internal.pagemem.PagePool

public class PagePool
extends Object

Field Summary

Fields

Modifier and Type	Field	Description
protected long	freePageListPtr	Pointer to the address of the free page list.
static final long	INVALID_REL_PTR	Relative null pointer
protected long	lastAllocatedIdxPtr
protected long	pagesBase	Pages base.
protected final AtomicInteger	pagesCntr	Pool pages counter.
protected final DirectMemoryRegion	region	Direct memory region.
static final long	REL_PTR_MASK	Relative pointer mask
static final int	REL_PTR_NUM_BITS	Number of lower bits which a relative page address may occupy.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	PagePool(DirectMemoryRegion region, int sysPageSize, OffheapReadWriteLock rwLock)

Method Summary

Modifier and Type	Method	Description
long	borrowOrAllocateFreePage(int tag)	Allocates a new free page.
static int	estimateNumberOfPages(long memory, int sysPageSize)	Returns upper bound for total number of pages in pool with the given parameters.
static long	estimateRequiredMemory(int numPages, int sysPageSize)	Returns required memory in bytes to accommodate the given number of pages.
DirectMemoryRegion	getMemoryRegion()
int	pages()
int	releaseFreePage(long relPtr)
int	size()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

REL_PTR_NUM_BITS

public static final int REL_PTR_NUM_BITS

Number of lower bits which a relative page address may occupy. Must be less than or equal to 32.

See Also:

• Constant Field Values

REL_PTR_MASK

public static final long REL_PTR_MASK

Relative pointer mask

See Also:

• Constant Field Values

INVALID_REL_PTR

public static final long INVALID_REL_PTR

Relative null pointer

See Also:

• Constant Field Values

region

protected final DirectMemoryRegion region

Direct memory region.

pagesCntr

protected final AtomicInteger pagesCntr

Pool pages counter.

lastAllocatedIdxPtr

protected long lastAllocatedIdxPtr

freePageListPtr

protected long freePageListPtr

Pointer to the address of the free page list.

pagesBase

protected long pagesBase

Pages base.

Constructor Details

PagePool

protected PagePool(DirectMemoryRegion region,
 int sysPageSize,
 OffheapReadWriteLock rwLock)

Parameters:

idx - Index.

region - Region

Method Details

borrowOrAllocateFreePage

public long borrowOrAllocateFreePage(int tag)
                              throws GridOffHeapOutOfMemoryException

Allocates a new free page.

Parameters:

tag - Tag to initialize page RW lock.

Returns:

Relative pointer to the allocated page.

Throws:

GridOffHeapOutOfMemoryException - If failed to allocate new free page.

releaseFreePage

public int releaseFreePage(long relPtr)

Parameters:

relPtr - Relative pointer to free.

Returns:

Resulting number of pages in pool if pages counter is enabled, 0 otherwise.

pages

public int pages()

Returns:

Max number of pages in the pool.

size

public int size()

Returns:

Number of pages in the list.

getMemoryRegion

public DirectMemoryRegion getMemoryRegion()

Returns:

direct memory region used by the pool

estimateNumberOfPages

public static int estimateNumberOfPages(long memory,
 int sysPageSize)

Returns upper bound for total number of pages in pool with the given parameters.

Parameters:

memory - total memory in bytes

sysPageSize - pages size in bytes

Returns:

upper bound for total number of pages in pool with the given parameters

estimateRequiredMemory

public static long estimateRequiredMemory(int numPages,
 int sysPageSize)

Returns required memory in bytes to accommodate the given number of pages.

Parameters:

numPages - number of pages

sysPageSize - pages size in bytes

Returns:

required memory in bytes to accommodate the given number of pages