respect non-reserved Memory in GenerationMemoryStrategy

and enable it again

source/net/yacy/kelondro/util/GenerationMemoryStrategy.java

@@ -94,6 +94,14 @@ public class GenerationMemoryStrategy extends MemoryStrategy {
 		return heap.getHeapMemoryUsage().getMax();
     }
     
+    /**
+     * currently not reserved memory
+     * @return bytes
+     */
+    private final long unreserved() {
+    	return Math.max(0, maxMemory() - total());
+    }
+
 	/**
      * checks if a specified amount of bytes are available
      * after the jvm recycled unused objects
@@ -124,7 +132,7 @@ public class GenerationMemoryStrategy extends MemoryStrategy {
      */
     private final long oldAvailable() {
     	final MemoryUsage usage = getUsage(old, true);
-    	return usage.getCommitted() - usage.getUsed();
+    	return unreserved() + usage.getCommitted() - usage.getUsed();
     }
     
     /**

source/net/yacy/kelondro/util/MemoryControl.java

@@ -37,6 +37,9 @@ public class MemoryControl {
     	if (strategy == null || strategy.hasError()) {
     		if (!usingStandardStrategy) {
     			strategy = new GenerationMemoryStrategy();
+//    			if (strategy.hasError()) { // perhaps we do have a G1
+//    				strategy = new G1MemoryStrategy();
+//    			}
     	    	// fall back if error detected
     	    	if (strategy.hasError()) {
     	    		usingStandardStrategy = true;
@@ -50,12 +53,10 @@ public class MemoryControl {
     }
 
     public final static void setStandardStrategy(final boolean std) {
-        /*
         if (usingStandardStrategy != std) {
     		usingStandardStrategy = std;
     		strategy = null;
     	}
-    	*/
     }
 
     /**