From 0d81f9d6452641f1f16b92dd95d756ed86862d80 Mon Sep 17 00:00:00 2001
From: Christian Haeubl <christian.haeubl@oracle.com>
Date: Tue, 30 Sep 2025 10:32:19 +0200
Subject: [PATCH] Only call updateSizeParameters() if DynamicCollectionPolicy
 is used.

---
 .../oracle/svm/core/genscavenge/CollectionPolicy.java  |  9 +++++++++
 .../svm/core/genscavenge/DynamicCollectionPolicy.java  | 10 ++++++++++
 .../src/com/oracle/svm/core/genscavenge/GCImpl.java    |  6 +-----
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/CollectionPolicy.java b/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/CollectionPolicy.java
index c9f79bd8ea72..4f446021466c 100644
--- a/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/CollectionPolicy.java
+++ b/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/CollectionPolicy.java
@@ -31,6 +31,7 @@
 import com.oracle.svm.core.SubstrateOptions;
 import com.oracle.svm.core.Uninterruptible;
 import com.oracle.svm.core.heap.GCCause;
+import com.oracle.svm.core.heap.OutOfMemoryUtil;
 import com.oracle.svm.core.heap.PhysicalMemory;
 import com.oracle.svm.core.util.UserError;
 import com.oracle.svm.util.ReflectionUtil;
@@ -217,4 +218,12 @@ static boolean shouldCollectYoungGenSeparately(boolean defaultValue) {
     default boolean isOutOfMemory(UnsignedWord usedBytes) {
         return usedBytes.aboveThan(getMaximumHeapSize());
     }
+
+    /**
+     * Invoked after a garbage collection when the maximum heap size has been exceeded. Can be
+     * overridden to recover from OOM.
+     */
+    default void onMaximumHeapSizeExceeded() {
+        throw OutOfMemoryUtil.heapSizeExceeded();
+    }
 }
diff --git a/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/DynamicCollectionPolicy.java b/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/DynamicCollectionPolicy.java
index 96ebd09d922f..b61c9418016f 100644
--- a/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/DynamicCollectionPolicy.java
+++ b/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/DynamicCollectionPolicy.java
@@ -58,4 +58,14 @@ public boolean isOutOfMemory(UnsignedWord usedBytes) {
 
         return super.isOutOfMemory(usedBytes);
     }
+
+    @Override
+    public void onMaximumHeapSizeExceeded() {
+        if (isOutOfMemory(HeapImpl.getAccounting().getUsedBytes())) {
+            super.onMaximumHeapSizeExceeded();
+        } else {
+            /* No longer out-of-memory - update the heap size parameters to reflect that. */
+            GCImpl.getPolicy().updateSizeParameters();
+        }
+    }
 }
diff --git a/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/GCImpl.java b/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/GCImpl.java
index c44a2cbe986d..412cc94e02dd 100644
--- a/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/GCImpl.java
+++ b/substratevm/src/com.oracle.svm.core.genscavenge/src/com/oracle/svm/core/genscavenge/GCImpl.java
@@ -190,11 +190,7 @@ private void collect(GCCause cause, boolean forceFullGC) {
         if (!hasNeverCollectPolicy()) {
             boolean outOfMemory = collectWithoutAllocating(cause, forceFullGC);
             if (outOfMemory) {
-                if (getPolicy().isOutOfMemory(HeapImpl.getAccounting().getUsedBytes())) {
-                    throw OutOfMemoryUtil.heapSizeExceeded();
-                } else {
-                    GCImpl.getPolicy().updateSizeParameters();
-                }
+                getPolicy().onMaximumHeapSizeExceeded();
             }
         }
     }