feature flag

Author: jan-elastic

distribution/tools/server-cli/src/main/java/org/elasticsearch/server/cli/MachineDependentHeap.java

@@ -11,6 +11,7 @@
 
 import org.elasticsearch.cluster.node.DiscoveryNodeRole;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.util.FeatureFlag;
 import org.elasticsearch.node.NodeRoleSettings;
 
 import java.io.IOException;
@@ -37,6 +38,8 @@ public class MachineDependentHeap {
     protected static final long MAX_HEAP_SIZE = GB * 31; // 31GB
     protected static final long MIN_HEAP_SIZE = 1024 * 1024 * 128; // 128MB
 
+    private static final FeatureFlag KILL_NEW_ML_MEMORY_COMPUTATION_FEATURE_FLAG = new FeatureFlag("kill_new_ml_memory_computation");
+
     public MachineDependentHeap() {}
 
     /**
@@ -104,6 +107,10 @@ protected int getHeapSizeMb(Settings nodeSettings, MachineNodeRole role, long av
             case ML_ONLY -> {
                 double heapFractionBelow16GB = 0.4 / (1.0 + JvmErgonomics.DIRECT_MEMORY_TO_HEAP_FACTOR);
                 double heapFractionAbove16GB = 0.1 / (1.0 + JvmErgonomics.DIRECT_MEMORY_TO_HEAP_FACTOR);
+                if (KILL_NEW_ML_MEMORY_COMPUTATION_FEATURE_FLAG.isEnabled()) {
+                    heapFractionBelow16GB = 0.4;
+                    heapFractionAbove16GB = 0.1;
+                }
                 if (availableMemory <= GB * 16) {
                     yield mb((long) (availableMemory * heapFractionBelow16GB), 4);
                 } else {

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/MachineLearning.java

@@ -41,6 +41,7 @@
 import org.elasticsearch.common.settings.SettingsModule;
 import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.unit.Processors;
+import org.elasticsearch.common.util.FeatureFlag;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.env.Environment;
@@ -557,6 +558,8 @@ public class MachineLearning extends Plugin
         License.OperationMode.PLATINUM
     );
 
+    private static final FeatureFlag KILL_NEW_ML_MEMORY_COMPUTATION_FEATURE_FLAG = new FeatureFlag("kill_new_ml_memory_computation");
+
     @Override
     public Map<String, Processor.Factory> getProcessors(Processor.Parameters parameters) {
         if (this.enabled == false) {
@@ -846,7 +849,11 @@ public Settings additionalSettings() {
                 Long.toString(OsProbe.getInstance().osStats().getMem().getAdjustedTotal().getBytes())
             );
 
-            addMlNodeAttribute(additionalSettings, jvmSizeAttrName, Long.toString(JvmInfo.jvmInfo().getMem().getTotalMax().getBytes()));
+            long jvmSize = JvmInfo.jvmInfo().getMem().getTotalMax().getBytes();
+            if (KILL_NEW_ML_MEMORY_COMPUTATION_FEATURE_FLAG.isEnabled()) {
+                jvmSize = Runtime.getRuntime().maxMemory();
+            }
+            addMlNodeAttribute(additionalSettings, jvmSizeAttrName, Long.toString(jvmSize));
             addMlNodeAttribute(
                 additionalSettings,
                 deprecatedAllocatedProcessorsAttrName,