8354078: Implement JEP 521: Generational Shenandoah

Reviewed-by: ysr

Author: William Kemper

src/hotspot/share/gc/shenandoah/mode/shenandoahGenerationalMode.hpp

@@ -32,7 +32,7 @@ class ShenandoahGenerationalMode : public ShenandoahMode {
   virtual void initialize_flags() const;
   virtual const char* name()     { return "Generational"; }
   virtual bool is_diagnostic()   { return false; }
-  virtual bool is_experimental() { return true; }
+  virtual bool is_experimental() { return false; }
   virtual bool is_generational() { return true; }
 };
 

test/hotspot/jtreg/gc/shenandoah/options/TestModeUnlock.java

@@ -47,7 +47,7 @@ enum Mode {
     public static void main(String[] args) throws Exception {
         testWith("-XX:ShenandoahGCMode=satb",         Mode.PRODUCT);
         testWith("-XX:ShenandoahGCMode=passive",      Mode.DIAGNOSTIC);
-        testWith("-XX:ShenandoahGCMode=generational", Mode.EXPERIMENTAL);
+        testWith("-XX:ShenandoahGCMode=generational", Mode.PRODUCT);
     }
 
     private static void testWith(String h, Mode mode) throws Exception {