8349007: The jtreg test ResolvedMethodTableHash takes excessive time

Reviewed-by: lmesnik, matsaave

src/hotspot/share/prims/resolvedMethodTable.cpp

@@ -175,7 +175,13 @@ oop ResolvedMethodTable::find_method(const Method* method) {
 
   ResolvedMethodTableLookup lookup(thread, method_hash(method), method);
   ResolvedMethodGet rmg(thread, method);
-  _local_table->get(thread, lookup, rmg);
+  bool rehash_warning = false;
+  _local_table->get(thread, lookup, rmg, &rehash_warning);
+  if (rehash_warning) {
+    // if load factor is low but we need to rehash that's a problem with the hash function.
+    log_info(membername, table)("Rehash warning, load factor %g", get_load_factor());
+    trigger_concurrent_work();
+  }
 
   return rmg.get_res_oop();
 }

test/hotspot/jtreg/runtime/MemberName/ResolvedMethodTableHash.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,7 +25,11 @@
  * @test
  * @bug 8249719
  * @summary ResolvedMethodTable hash function should take method class into account
- * @run main/othervm/manual -Xmx256m -XX:MaxMetaspaceSize=256m ResolvedMethodTableHash 200000
+ * @requires vm.flagless
+ * @library /test/lib
+ * @modules java.base/jdk.internal.misc
+ *          java.management
+ * @run driver ResolvedMethodTableHash
  */
 
 import java.lang.invoke.MethodHandle;
@@ -35,11 +39,15 @@ import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.List;
 
-// The test generates thousands MethodHandles to the methods of the same name
+import jdk.test.lib.process.OutputAnalyzer;
-// and the same signature. This should not take too long, unless Method hash
+import jdk.test.lib.process.ProcessTools;
-// function takes only the name and the signature as an input.
-public class ResolvedMethodTableHash extends ClassLoader {
 
+// The test generates a thousand MethodHandles to the methods of the same name
+// and the same signature. The rehash warning shouldn't be returned, unless Method hash
+// function takes only the name and the signature as an input.
+public class ResolvedMethodTableHash {
+
+    public static class ResolvedMethodTableHashTest extends ClassLoader {
         // Generate a MethodHandle for ClassName.m()
         private MethodHandle generate(String className) throws ReflectiveOperationException {
             byte[] buf = new byte[100];
@@ -52,7 +60,7 @@ public class ResolvedMethodTableHash extends ClassLoader {
             byte[] buf = new byte[100];
             int size = writeClass(buf, "MH$$");
             // use different classloader instances to load the classes with the same name
-        Class<?> cls = new ResolvedMethodTableHash().defineClass(null, buf, 0, size);
+            Class<?> cls = new ResolvedMethodTableHashTest().defineClass(null, buf, 0, size);
             return MethodHandles.publicLookup().findStatic(cls, "m", MethodType.methodType(void.class));
         }
 
@@ -84,10 +92,11 @@ public class ResolvedMethodTableHash extends ClassLoader {
         }
 
         public static void main(String[] args) throws Exception {
-        ResolvedMethodTableHash generator = new ResolvedMethodTableHash();
+
+            ResolvedMethodTableHashTest generator = new ResolvedMethodTableHashTest();
             List<MethodHandle> handles = new ArrayList<>();
 
-        int count = args.length > 0 ? Integer.parseInt(args[0]) : 200000;
+            int count = 1001;
 
             for (int i = 0; i < count; i++) {
                 // prevents metaspace oom
@@ -104,3 +113,15 @@ public class ResolvedMethodTableHash extends ClassLoader {
             System.out.println("Test passed");
         }
     }
+
+    public static void main(String[] args) throws Exception {
+
+        // Running the table with only 1000 entries should not provoke a needs rehash warning, unless the hash code is bad.
+        ProcessBuilder pb = ProcessTools.createLimitedTestJavaProcessBuilder("-Xlog:membername+table",
+                                                                             ResolvedMethodTableHashTest.class.getName());
+        OutputAnalyzer output = new OutputAnalyzer(pb.start());
+        output.shouldNotContain("[membername,table] Rehash warning, load factor");
+        output.shouldContain("Generated 1000 handles");
+        output.shouldHaveExitValue(0);
+    }
+}