Add missed scan for modules in System and Application class loaders

GC scans System and Application class loaders seperately as permanent roots. Scanning of the modules has been missed for this path. related eclipse-openj9#18805 Signed-off-by: Dmitri Pivkine <[email protected]>
dmitripivkine · Feb 27, 2024 · 0e069b3 · 0e069b3
1 parent a78d091
commit 0e069b3
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Showing 2 changed files with 32 additions and 24 deletions.
diff --git a/runtime/gc_base/RootScanner.cpp b/runtime/gc_base/RootScanner.cpp
@@ -395,44 +395,44 @@ MM_RootScanner::scanPermanentClasses(MM_EnvironmentBase *env)
 {
 	reportScanningStarted(RootScannerEntity_PermanentClasses);
 
+	/* Do systemClassLoader */
+	scanClassloader(env, static_cast<J9JavaVM*>(_omrVM->_language_vm)->systemClassLoader);
+
+	/* Do applicationClassLoader */
+	scanClassloader(env, static_cast<J9JavaVM*>(_omrVM->_language_vm)->applicationClassLoader);
+
+	condYield();
+
+	reportScanningEnded(RootScannerEntity_PermanentClasses);
+}
+
+/**
+ * Scan all objects from class loader.
+ */
+void
+MM_RootScanner::scanClassloader(MM_EnvironmentBase *env, J9ClassLoader *classLoader)
+{
 	J9MemorySegment *segment = NULL;
 	J9Class *clazz = NULL;
 
-	/* Do systemClassLoader */
-	if (NULL != static_cast<J9JavaVM*>(_omrVM->_language_vm)->systemClassLoader) {
-		GC_ClassLoaderSegmentIterator segmentIterator(static_cast<J9JavaVM*>(_omrVM->_language_vm)->systemClassLoader, MEMORY_TYPE_RAM_CLASS);
-		while(NULL != (segment = segmentIterator.nextSegment())) {
-			if(_singleThread || J9MODRON_HANDLE_NEXT_WORK_UNIT(env)) {
+	if (NULL != classLoader) {
+		GC_ClassLoaderSegmentIterator segmentIterator(classLoader, MEMORY_TYPE_RAM_CLASS);
+		while (NULL != (segment = segmentIterator.nextSegment())) {
+			if (_singleThread || J9MODRON_HANDLE_NEXT_WORK_UNIT(env)) {
 				GC_ClassHeapIterator classHeapIterator(static_cast<J9JavaVM*>(_omrVM->_language_vm), segment);
-				while(NULL != (clazz = classHeapIterator.nextClass())) {
+				while (NULL != (clazz = classHeapIterator.nextClass())) {
 					doClass(clazz);
 					if (shouldYieldFromClassScan(100000)) {
 						yield();
 					}
 				}
 			}
 		}
-	}
 
-	/* Do applicationClassLoader */
-	if (NULL != static_cast<J9JavaVM*>(_omrVM->_language_vm)->applicationClassLoader) {
-		GC_ClassLoaderSegmentIterator segmentIterator(static_cast<J9JavaVM*>(_omrVM->_language_vm)->applicationClassLoader, MEMORY_TYPE_RAM_CLASS);
-		while(NULL != (segment = segmentIterator.nextSegment())) {
-			if(_singleThread || J9MODRON_HANDLE_NEXT_WORK_UNIT(env)) {
-				GC_ClassHeapIterator classHeapIterator(static_cast<J9JavaVM*>(_omrVM->_language_vm), segment);
-				while(NULL != (clazz = classHeapIterator.nextClass())) {
-					doClass(clazz);
-					if (shouldYieldFromClassScan(100000)) {
-						yield();
-					}
-				}
-			}
+		if (_singleThread || J9MODRON_HANDLE_NEXT_WORK_UNIT(env)) {
+			scanModularityObjects(classLoader);
 		}
 	}
-
-	condYield();
-
-	reportScanningEnded(RootScannerEntity_PermanentClasses);
 }
 #endif /* J9VM_GC_DYNAMIC_CLASS_UNLOADING */
 

diff --git a/runtime/gc_base/RootScanner.hpp b/runtime/gc_base/RootScanner.hpp
@@ -122,6 +122,14 @@ class MM_RootScanner : public MM_BaseVirtual
 	void scanArrayObject(MM_EnvironmentBase *env, J9Object *objectPtr, MM_MemoryPool *memoryPool, MM_HeapRegionManager *manager, uintptr_t memoryType);
 
 	bool isContinuationListEmpty(MM_EnvironmentBase *env);
+
+	/**
+	 * Scan all objects from class loader.
+	 * @param env thread GC environment
+	 * @param classLoader class loader address
+	 */
+	void scanClassloader(MM_EnvironmentBase *env, J9ClassLoader *classLoader);
+
 protected:
 	/* Family of yielding methods to be overridden by incremental scanners such
 	 * as the RealtimeRootScanner. The default implementations of these do