com.oracle.svm.core.thread

Class JavaVMOperation

java.lang.Object

com.oracle.svm.core.thread.VMOperation

com.oracle.svm.core.thread.JavaVMOperation

All Implemented Interfaces:

VMOperationControl.JavaAllocationFreeQueue.Element<JavaVMOperation>

Direct Known Subclasses:

HeapVerifierImpl.VerifyVMOperation, JavaVMOperation.ThunkOperation, MemoryWalkerImpl.MemoryWalkerVMOperation

public abstract class JavaVMOperation
extends VMOperation
implements VMOperationControl.JavaAllocationFreeQueue.Element<JavaVMOperation>

The abstract base class for all VM operations that are allocated on the Java heap. Allocating the VM operation on the Java heap is preferable but not always possible (see NativeVMOperation). JavaVMOperation objects should be short lived and only enqueued/executed once. For increased thread safety, it is prohibited to allocate JavaVMOperations that live in the image heap (see note below).

Note: the VM operation infrastructure supports that JavaVMOperations are reused and executed multiple times. However, extra care must be taken as each VM operation object can only be in the VM operation queue once. Therefore, it must be guaranteed that the VM operation is executed before it is enqueued again. Otherwise, this could result in various race conditions, especially if SubstrateOptions.UseDedicatedVMOperationThread is enabled.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JavaVMOperation.ThunkOperation A VMOperation that executes a thunk.

Nested classes/interfaces inherited from class com.oracle.svm.core.thread.VMOperation

VMOperation.SystemEffect

Field Summary

Fields

Modifier and Type	Field and Description
protected org.graalvm.nativeimage.IsolateThread	queuingThread

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	JavaVMOperation(String name, VMOperation.SystemEffect systemEffect)

Method Summary

Modifier and Type	Method and Description
void	enqueue()
static void	enqueueBlockingNoSafepoint(String name, SubstrateUtil.Thunk thunk) Convenience method for thunks that can be run by allocating a VMOperation.
static void	enqueueBlockingSafepoint(String name, SubstrateUtil.Thunk thunk) Convenience method for thunks that can be run by allocating a VMOperation.
JavaVMOperation	getNext()
protected org.graalvm.nativeimage.IsolateThread	getQueuingThread(NativeVMOperationData data)
protected boolean	hasWork()
protected boolean	hasWork(NativeVMOperationData data) Used to determine if a VM operation must be executed or if it can be skipped.
protected boolean	isFinished(NativeVMOperationData data)
protected abstract void	operate()
void	operate(NativeVMOperationData data)
protected void	setFinished(NativeVMOperationData data, boolean value)
void	setNext(JavaVMOperation value)
protected void	setQueuingThread(NativeVMOperationData data, org.graalvm.nativeimage.IsolateThread thread)

Methods inherited from class com.oracle.svm.core.thread.VMOperation

execute, getCausesSafepoint, getName, guaranteeGCInProgress, guaranteeInProgress, guaranteeInProgressAtSafepoint, guaranteeNotInProgress, isGC, isGCInProgress, isInProgress, isInProgressAtSafepoint

Methods inherited from class java.lang.Object

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

Field Detail

queuingThread

protected org.graalvm.nativeimage.IsolateThread queuingThread

Constructor Detail

JavaVMOperation

protected JavaVMOperation(String name,
                          VMOperation.SystemEffect systemEffect)

Method Detail

getNext

public JavaVMOperation getNext()

Specified by:

getNext in interface VMOperationControl.JavaAllocationFreeQueue.Element<JavaVMOperation>

setNext

public void setNext(JavaVMOperation value)

Specified by:

setNext in interface VMOperationControl.JavaAllocationFreeQueue.Element<JavaVMOperation>

enqueue

public void enqueue()

getQueuingThread

protected org.graalvm.nativeimage.IsolateThread getQueuingThread(NativeVMOperationData data)

Specified by:

getQueuingThread in class VMOperation

setQueuingThread

protected void setQueuingThread(NativeVMOperationData data,
                                org.graalvm.nativeimage.IsolateThread thread)

Specified by:

setQueuingThread in class VMOperation

isFinished

protected boolean isFinished(NativeVMOperationData data)

Specified by:

isFinished in class VMOperation

setFinished

protected void setFinished(NativeVMOperationData data,
                           boolean value)

Specified by:

setFinished in class VMOperation

hasWork

protected final boolean hasWork(NativeVMOperationData data)

Description copied from class: VMOperation

Used to determine if a VM operation must be executed or if it can be skipped. Regardless of the VMOperation.SystemEffect that was specified for the VM operation, this method might be called before or after a safepoint was initiated.

Overrides:

hasWork in class VMOperation

hasWork

protected boolean hasWork()

enqueueBlockingSafepoint

public static void enqueueBlockingSafepoint(String name,
                                            SubstrateUtil.Thunk thunk)

Convenience method for thunks that can be run by allocating a VMOperation.

enqueueBlockingNoSafepoint

public static void enqueueBlockingNoSafepoint(String name,
                                              SubstrateUtil.Thunk thunk)

Convenience method for thunks that can be run by allocating a VMOperation.

operate

public final void operate(NativeVMOperationData data)

Specified by:

operate in class VMOperation

operate

protected abstract void operate()