Merge pull request #18060 from babsingh/fix_scopedvaluecache

Store J9VMThread->scopedValueCache in the Continuation object
eclipse-openj9 · Sep 1, 2023 · 2cbea41 · 2cbea41
2 parents 2b34667 + 92cb9c9
commit 2cbea41
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Showing 4 changed files with 15 additions and 3 deletions.
diff --git a/jcl/src/java.base/share/classes/jdk/internal/vm/Continuation.java b/jcl/src/java.base/share/classes/jdk/internal/vm/Continuation.java
@@ -37,6 +37,13 @@ public class Continuation {
 	private long vmRef; /* J9VMContinuation */
 	protected Thread vthread; /* Parent VirtualThread */
 
+	/* The live thread's scopedValueCache is always kept in J9VMThread->scopedValueCache
+	 * whereas the unmounted thread's scopedValueCache is stored in this field. This
+	 * field is modified in ContinuationHelpers.hpp::swapFieldsWithContinuation. This
+	 * assures a one to one mapping between a java.lang.Thread and scopedValueCache.
+	 */
+	private Object[] scopedValueCache;
+
 	private final ContinuationScope scope;
 	private final Runnable runnable;
 	private Continuation parent;

diff --git a/runtime/oti/ContinuationHelpers.hpp b/runtime/oti/ContinuationHelpers.hpp
@@ -51,7 +51,7 @@ class VM_ContinuationHelpers {
 public:
 
 	static VMINLINE void
-	swapFieldsWithContinuation(J9VMThread *vmThread, J9VMContinuation *continuation, bool swapJ9VMthreadSavedRegisters = true)
+	swapFieldsWithContinuation(J9VMThread *vmThread, J9VMContinuation *continuation, j9object_t continuationObject, bool swapJ9VMthreadSavedRegisters = true)
 	{
 	/* Helper macro to swap fields between the two J9Class structs. */
 #define SWAP_MEMBER(fieldName, fieldType, class1, class2) \
@@ -84,6 +84,10 @@ class VM_ContinuationHelpers {
 		}
 		threadELS->i2jState = tempI2J;
 		SWAP_MEMBER(oldEntryLocalStorage, J9VMEntryLocalStorage*, threadELS, continuation);
+
+		j9object_t scopedValueCache = J9VMJDKINTERNALVMCONTINUATION_SCOPEDVALUECACHE(vmThread, continuationObject);
+		J9VMJDKINTERNALVMCONTINUATION_SET_SCOPEDVALUECACHE(vmThread, continuationObject, vmThread->scopedValueCache);
+		vmThread->scopedValueCache = scopedValueCache;
 	}
 
 	static VMINLINE ContinuationState volatile *

diff --git a/runtime/oti/vmconstantpool.xml b/runtime/oti/vmconstantpool.xml
@@ -413,6 +413,7 @@ SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0-only WITH Classpath-ex
 	<fieldref class="jdk/internal/vm/Continuation" name="state" signature="J" versions="19-"/>
 	<fieldref class="jdk/internal/vm/Continuation" name="parent" signature="Ljdk/internal/vm/Continuation;" versions="19-"/>
 	<fieldref class="jdk/internal/vm/Continuation" name="vthread" signature="Ljava/lang/Thread;" versions="19-"/>
+	<fieldref class="jdk/internal/vm/Continuation" name="scopedValueCache" signature="[Ljava/lang/Object;" versions="19-"/>
 
 	<!-- Field references needed to support Foreign Linker API. -->
 	<fieldref class="openj9/internal/foreign/abi/InternalDowncallHandler" name="cifNativeThunkAddr" signature="J" flags="opt_openjdkFfi" versions="17-"/>

diff --git a/runtime/vm/ContinuationHelpers.cpp b/runtime/vm/ContinuationHelpers.cpp
@@ -233,7 +233,7 @@ enterContinuation(J9VMThread *currentThread, j9object_t continuationObject)
 		currentThread->javaVM->memoryManagerFunctions->preMountContinuation(currentThread, continuationObject);
 	}
 
-	VM_ContinuationHelpers::swapFieldsWithContinuation(currentThread, continuation, started);
+	VM_ContinuationHelpers::swapFieldsWithContinuation(currentThread, continuation, continuationObject, started);
 
 	currentThread->currentContinuation = continuation;
 	/* Reset counters which determine if the current continuation is pinned. */
@@ -285,7 +285,7 @@ yieldContinuation(J9VMThread *currentThread, BOOLEAN isFinished)
 	}
 
 	currentThread->currentContinuation = NULL;
-	VM_ContinuationHelpers::swapFieldsWithContinuation(currentThread, continuation);
+	VM_ContinuationHelpers::swapFieldsWithContinuation(currentThread, continuation, continuationObject);
 
 	/* We need a full fence here to preserve happens-before relationship on PPC and other weakly
 	 * ordered architectures since learning/reservation is turned on by default. Since we have the