com.oracle.svm.core.os

Interface CommittedMemoryProvider

All Known Implementing Classes:

AbstractCommittedMemoryProvider, OSCommittedMemoryProvider

public interface CommittedMemoryProvider

A provider of ranges of committed memory, which is virtual memory that is backed by physical memory or swap space.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	CommittedMemoryProvider.Access

Field Summary

Fields

Modifier and Type	Field and Description
static org.graalvm.word.UnsignedWord	UNALIGNED Value for alignment parameters that indicates that no specific alignment is required (other than the granularity usually).

Method Summary

Modifier and Type	Method and Description
default void	afterGarbageCollection(boolean completeCollection) Called by the garbage collector after a collection has ended, as an opportunity to perform lazy operations, sanity checks or clean-ups.
org.graalvm.word.Pointer	allocate(org.graalvm.word.UnsignedWord nbytes, org.graalvm.word.UnsignedWord alignment, boolean executable) Allocate a block of committed memory.
default void	beforeGarbageCollection() Called by the garbage collector before a collection is started, as an opportunity to perform lazy operations, sanity checks or clean-ups.
boolean	free(org.graalvm.word.PointerBase start, org.graalvm.word.UnsignedWord nbytes, org.graalvm.word.UnsignedWord alignment, boolean executable) Release a block of committed memory that was allocated with CommittedMemoryProvider.allocate(org.graalvm.word.UnsignedWord, org.graalvm.word.UnsignedWord, boolean), requiring the exact same parameter values that were originally passed to CommittedMemoryProvider.allocate(org.graalvm.word.UnsignedWord, org.graalvm.word.UnsignedWord, boolean).
static CommittedMemoryProvider	get()
default org.graalvm.word.UnsignedWord	getGranularity() Returns the granularity of committed memory management, which is typically the same as that of virtual memory management.
boolean	guaranteesHeapPreferredAddressSpaceAlignment() Returns whether this provider will always guarantee a heap address space alignment of Heap.getPreferredAddressSpaceAlignment() at image runtime, which may also depend on ImageHeapProvider.guaranteesHeapPreferredAddressSpaceAlignment().
int	initialize(org.graalvm.nativeimage.c.type.WordPointer isolatePointer, CEntryPointCreateIsolateParameters parameters) Performs initializations for the current isolate, before any other methods of this interface may be called.
boolean	protect(org.graalvm.word.PointerBase start, org.graalvm.word.UnsignedWord nbytes, EnumSet<CommittedMemoryProvider.Access> access) Change access permissions for a block of committed memory that was allocated with CommittedMemoryProvider.allocate(org.graalvm.word.UnsignedWord, org.graalvm.word.UnsignedWord, boolean).
int	tearDown() Tear down for the current isolate.

Field Detail

UNALIGNED

static final org.graalvm.word.UnsignedWord UNALIGNED

Value for alignment parameters that indicates that no specific alignment is required (other than the granularity usually).

Method Detail

get

static CommittedMemoryProvider get()

guaranteesHeapPreferredAddressSpaceAlignment

boolean guaranteesHeapPreferredAddressSpaceAlignment()

Returns whether this provider will always guarantee a heap address space alignment of Heap.getPreferredAddressSpaceAlignment() at image runtime, which may also depend on ImageHeapProvider.guaranteesHeapPreferredAddressSpaceAlignment().

initialize

int initialize(org.graalvm.nativeimage.c.type.WordPointer isolatePointer,
               CEntryPointCreateIsolateParameters parameters)

Performs initializations for the current isolate, before any other methods of this interface may be called.

Returns:

zero in case of success, non-zero in case of an error.

tearDown

int tearDown()

Tear down for the current isolate. This must be the last method of this interface that is called in an isolate.

Returns:

zero in case of success, non-zero in case of an error.

getGranularity

default org.graalvm.word.UnsignedWord getGranularity()

Returns the granularity of committed memory management, which is typically the same as that of virtual memory management.

allocate

org.graalvm.word.Pointer allocate(org.graalvm.word.UnsignedWord nbytes,
                                  org.graalvm.word.UnsignedWord alignment,
                                  boolean executable)

Allocate a block of committed memory.

Parameters:

nbytes - The number of bytes to allocate, which is rounded up to the next multiple of the granularity if required.

alignment - The required alignment of the block start, or CommittedMemoryProvider.UNALIGNED.

executable - Whether the block must be executable.

Returns:

The start of the allocated block, or WordFactory.nullPointer() in case of an error.

free

boolean free(org.graalvm.word.PointerBase start,
             org.graalvm.word.UnsignedWord nbytes,
             org.graalvm.word.UnsignedWord alignment,
             boolean executable)

Release a block of committed memory that was allocated with CommittedMemoryProvider.allocate(org.graalvm.word.UnsignedWord, org.graalvm.word.UnsignedWord, boolean), requiring the exact same parameter values that were originally passed to CommittedMemoryProvider.allocate(org.graalvm.word.UnsignedWord, org.graalvm.word.UnsignedWord, boolean).

Parameters:

start - The start of the memory block, as returned by CommittedMemoryProvider.allocate(org.graalvm.word.UnsignedWord, org.graalvm.word.UnsignedWord, boolean).

nbytes - The originally requested size in bytes.

alignment - The originally requested alignment.

executable - Whether the block was requested to be executable.

Returns:

true on success, or false otherwise.

beforeGarbageCollection

default void beforeGarbageCollection()

Called by the garbage collector before a collection is started, as an opportunity to perform lazy operations, sanity checks or clean-ups.

afterGarbageCollection

default void afterGarbageCollection(boolean completeCollection)

Called by the garbage collector after a collection has ended, as an opportunity to perform lazy operations, sanity checks or clean-ups.

Parameters:

completeCollection - Whether the garbage collector has performed a full collection.

protect

boolean protect(org.graalvm.word.PointerBase start,
                org.graalvm.word.UnsignedWord nbytes,
                EnumSet<CommittedMemoryProvider.Access> access)

Change access permissions for a block of committed memory that was allocated with CommittedMemoryProvider.allocate(org.graalvm.word.UnsignedWord, org.graalvm.word.UnsignedWord, boolean).

Parameters:

start - The start of the address range to be protected, which must be a multiple of the granularity.

nbytes - The size in bytes of the address range to be protected, which will be rounded up to a multiple of the granularity.

access - The modes in which the memory is permitted to be accessed, see CommittedMemoryProvider.Access.

Returns:

true on success, or false otherwise.