org.jikesrvm.mm.mmtk

Class Memory

java.lang.Object

org.mmtk.vm.Memory

org.jikesrvm.mm.mmtk.Memory

public class Memory
extends Memory

Field Summary

Fields

Modifier and Type	Field and Description
private static int	BOOT_SEGMENT_MB
private static ImmortalSpace	bootSpace
private static int	LOG_BYTES_IN_PAGE_LIE A lie about the size of a virtual memory page.

Constructor Summary

Constructors

Constructor and Description
Memory()

Method Summary

Modifier and Type	Method and Description
void	collectorPrepareVMSpace() Per-collector preparation for a collection.
void	collectorReleaseVMSpace() Per-collector post-collection work.
void	dumpMemory(Address start, int beforeBytes, int afterBytes) Logs the contents of an address and the surrounding memory to the error output.
int	dzmmap(Address start, int size) Demand zero mmaps an area of virtual memory.
protected int	getAlignmentValueConstant()
protected Address	getAvailableEndConstant()
protected Address	getAvailableStartConstant()
protected Address	getHeapEndConstant()
protected Address	getHeapStartConstant()
protected byte	getLogBytesInAddressConstant()
protected byte	getLogBytesInPageConstant()
protected byte	getLogBytesInWordConstant()
protected byte	getLogMinAlignmentConstant()
protected byte	getMaxAlignmentShiftConstant() On Intel we align code to 16 bytes as recommended in the optimization manual.
protected int	getMaxBytesPaddingConstant()
ImmortalSpace	getVMSpace() Return the space associated with/reserved for the VM.
void	globalPrepareVMSpace() Global preparation for a collection.
void	globalReleaseVMSpace() Global post-collection work.
void	isync() Wait for all preceeding instructions to complete and discard any prefetched instructions on this processor.
boolean	mprotect(Address start, int size) Protects access to an area of virtual memory.
boolean	munprotect(Address start, int size) Allows access to an area of virtual memory.
void	setHeapRange(int id, Address start, Address end) Sets the range of addresses associated with a heap.
void	sync() Wait for preceeding cache flush/invalidate instructions to complete on all processors.
void	zero(boolean useNT, Address start, Extent len) Zero a region of memory.

Methods inherited from class java.lang.Object

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

Field Detail

LOG_BYTES_IN_PAGE_LIE

private static final int LOG_BYTES_IN_PAGE_LIE

A lie about the size of a virtual memory page. MMTk currently assumes that the page size is known at bootimage building time (see RVM-816), so we need to pass some kind of value.

See Also:

Constant Field Values

bootSpace

private static ImmortalSpace bootSpace

BOOT_SEGMENT_MB

private static final int BOOT_SEGMENT_MB

Constructor Detail

Memory

public Memory()

Method Detail

getHeapStartConstant

protected final Address getHeapStartConstant()

Specified by:

getHeapStartConstant in class Memory

Returns:

The lowest address in the virtual address space known to MMTk

getHeapEndConstant

protected final Address getHeapEndConstant()

Specified by:

getHeapEndConstant in class Memory

Returns:

The highest address in the virtual address space known to MMTk

getAvailableStartConstant

protected final Address getAvailableStartConstant()

Specified by:

getAvailableStartConstant in class Memory

Returns:

The lowest address in the contiguous address space available to MMTk

getAvailableEndConstant

protected final Address getAvailableEndConstant()

Specified by:

getAvailableEndConstant in class Memory

Returns:

The highest address in the contiguous address space available to MMTk

getLogBytesInAddressConstant

protected final byte getLogBytesInAddressConstant()

Specified by:

getLogBytesInAddressConstant in class Memory

Returns:

The log base two of the size of an address

getLogBytesInWordConstant

protected final byte getLogBytesInWordConstant()

Specified by:

getLogBytesInWordConstant in class Memory

Returns:

The log base two of the size of a word

getLogBytesInPageConstant

protected final byte getLogBytesInPageConstant()

Specified by:

getLogBytesInPageConstant in class Memory

Returns:

The log base two of the size of an OS page

getLogMinAlignmentConstant

protected final byte getLogMinAlignmentConstant()

Specified by:

getLogMinAlignmentConstant in class Memory

Returns:

The log base two of the minimum allocation alignment

getMaxBytesPaddingConstant

protected final int getMaxBytesPaddingConstant()

Specified by:

getMaxBytesPaddingConstant in class Memory

Returns:

The maximum number of bytes of padding to prepend to an object

getAlignmentValueConstant

protected final int getAlignmentValueConstant()

Specified by:

getAlignmentValueConstant in class Memory

Returns:

The value to store in alignment holes

getMaxAlignmentShiftConstant

protected final byte getMaxAlignmentShiftConstant()

On Intel we align code to 16 bytes as recommended in the optimization manual.

Specified by:

getMaxAlignmentShiftConstant in class Memory

Returns:

The log base two of (MAX_ALIGNMENT/MIN_ALIGNMENT)

getVMSpace

public final ImmortalSpace getVMSpace()

Return the space associated with/reserved for the VM. In the case of Jikes RVM this is the boot image space.

The boot image space must be mapped at the start of available virtual memory, hence we use the constructor that requests the lowest address in the address space. The address space awarded to this space depends on the order in which the request is made. If this request is not the first request for virtual memory then the Space allocator will die with an error stating that the request could not be satisfied. The remedy is to ensure it is initialized first.

Specified by:

getVMSpace in class Memory

Returns:

The space managed by the virtual machine. In this case, the boot image space is returned.

globalPrepareVMSpace

public final void globalPrepareVMSpace()

Description copied from class: Memory

Global preparation for a collection.

Specified by:

globalPrepareVMSpace in class Memory

collectorPrepareVMSpace

public final void collectorPrepareVMSpace()

Description copied from class: Memory

Per-collector preparation for a collection.

Specified by:

collectorPrepareVMSpace in class Memory

collectorReleaseVMSpace

public final void collectorReleaseVMSpace()

Description copied from class: Memory

Per-collector post-collection work.

Specified by:

collectorReleaseVMSpace in class Memory

globalReleaseVMSpace

public final void globalReleaseVMSpace()

Description copied from class: Memory

Global post-collection work.

Specified by:

globalReleaseVMSpace in class Memory

setHeapRange

public final void setHeapRange(int id,
                               Address start,
                               Address end)

Description copied from class: Memory

Sets the range of addresses associated with a heap.

Specified by:

setHeapRange in class Memory

Parameters:

id - the heap identifier

start - the address of the start of the heap

end - the address of the end of the heap

dzmmap

public final int dzmmap(Address start,
                        int size)

Description copied from class: Memory

Demand zero mmaps an area of virtual memory.

Specified by:

dzmmap in class Memory

Parameters:

start - the address of the start of the area to be mapped

size - the size, in bytes, of the area to be mapped

Returns:

0 if successful, otherwise the system errno

mprotect

public final boolean mprotect(Address start,
                              int size)

Description copied from class: Memory

Protects access to an area of virtual memory.

Specified by:

mprotect in class Memory

Parameters:

start - the address of the start of the area to be mapped

size - the size, in bytes, of the area to be mapped

Returns:

true if successful, otherwise false

munprotect

public final boolean munprotect(Address start,
                                int size)

Description copied from class: Memory

Allows access to an area of virtual memory.

Specified by:

munprotect in class Memory

Parameters:

start - the address of the start of the area to be mapped

size - the size, in bytes, of the area to be mapped

Returns:

true if successful, otherwise false

zero

public final void zero(boolean useNT,
                       Address start,
                       Extent len)

Description copied from class: Memory

Zero a region of memory.

Specified by:

zero in class Memory

Parameters:

useNT - Use non temporal instructions (if available)

start - Start of address range (inclusive)

len - Length in bytes of range to zero

dumpMemory

public final void dumpMemory(Address start,
                             int beforeBytes,
                             int afterBytes)

Description copied from class: Memory

Logs the contents of an address and the surrounding memory to the error output.

Specified by:

dumpMemory in class Memory

Parameters:

start - the address of the memory to be dumped

beforeBytes - the number of bytes before the address to be included

afterBytes - the number of bytes after the address to be included

sync

public final void sync()

Description copied from class: Memory

Wait for preceeding cache flush/invalidate instructions to complete on all processors. Ensures that all memory writes before this point are visible to all processors.

Specified by:

sync in class Memory

isync

public final void isync()

Description copied from class: Memory

Wait for all preceeding instructions to complete and discard any prefetched instructions on this processor. Also prevents the compiler from performing code motion across this point.

Specified by:

isync in class Memory